Split (3)

train · 130k rows

description stringlengths 2.98k 3.35M	abstract stringlengths 94 10.6k	cpc int64 0 8
BACKGROUND OF THE INVENTION Conventional dental amalgams are among the most widely used restorative materials employed in dentistry. These amalgams are made by mixing a dental amalgam alloy with mercury, the amount of mercury varying from 40% to 60% by weight of the alloy, to obtain the necessary and desirable working quality or plasticity required, in accordance with the manufacturer's recommendations. The standard or conventional amalgam alloy composition as currently certified by the American Dental Association (ADA) comprises: Silver 65.0% minimumTin 29.0% maximumCopper 6.0% maximumZinc 2.0% maximum An amalgam alloy of the above composition containing mercury up to 3.0% maximum in addition, is reportedly used extensively in European countries but is not very popular in the United States. Such alloys are described as "preamalgamated" alloys. Metallurgically, the principal component of the standard or conventional amalgam alloy is the gamma phase, Ag 3 Sn. The amalgamation reaction involves the solution of Ag 3 Sn in mercury (Hg), from which a precipitation of silver-mercury (Ag 2 Hg 3 , gamma-1 phase) and tin-mercury (Sn 7 Hg, gamma-2 phase) takes place. The setting or hardening of the amalgam, which occurs in the tooth cavity, is associated with and responsive to these metallurgical changes. The amount of tin-mercury (gamma-2) phase and the silver-mercury (gamma-1) phase increases with the amount of mercury added to the silver-tin (gamma) phase. In current clinical practice, wherein the mercury content ranges between 40-60% by weight of the amalgam alloy to which it is added, a major portion of the conventional alloy, in particulate form, will react with the mercury. Thus, in a hardened or set amalgam structure, one finds some unreacted silver-tin particles bonded or cemented together in a matrix of sliver-mercury and tin-mercury compounds. Trace amounts of a copper-tin complex have also been detected in the microstructure of a set amalgam. The tin-mercury (gamma-2) phase has been held responsible for the tarnish and corrosion failure of the conventional dental amalgam. It has been recognized that this is due to an electrochemical polarization, resulting in the deterioration of the tin-mercury (gamma-2) phase and an eventual weakening of the physical structure. It has also been found that the tarnish of such dental amalgams results from the attack on the silver-mercury (gamma-1) phase by sulfide ions generated from ingested food materials. It has further been observed and recognized that both the tin-mercury (gamma-2) and the silver-mercury (gamma-1) phases are relatively weak, and the brittle failure of amalgam restorations is believed to occur through the initiation of cracks in the tin-mercury phase and the inter-granular fracture of the silver-mercury phase. Moreover, it has been found that the silver-mercury phase is responsible for the creep of dental amalgams which in turn is related to marginal fracture. These defects of conventional dental amalgams account for the principal limitations of amalgam restorations. A relatively new amalgam alloy is one disclosed in Youdelis U.S. Pat. No. 3,305,356 issued Feb. 21, 1967 for "Dental Amalgam". An alloy marketed under this patent has attracted widespread attention in view of the reportedly improved clinical behavior of the amalgams. One of these alloys as marketed consists of a mechanical mixture of two silver-rich alloys or components. The first of these is a conventional amalgam alloy of the silver-tin (copper-zinc) type. The second component is a silver-copper (AgCu) eutectic alloy, combined with the conventional alloy in a ratio of two parts of the conventional alloy to one part of the eutectic, by weight. The amalgam made by these components, when combined with mercury in the 40-60% proportions, is reported to contain very little or no tin-mercury (gamma-2) phase, but the amount of silver-mercury phase produced is not any less than that which is observed in a conventional amalgam for equivalent mercury content. Other microstructural constituents believed to be present in this amalgam include copper-tin complex, and unreacted silver-tin (gamma) phase and silver-copper (AgCu) eutectic particles. According to the Youdelis patent disclosure and as expected, any significant oxidation of the silver-copper eutectic tends to retard amalgamation and unduly increase the setting time of the amalgam. Further, it has been reported that if the copper concentration in the conventional dental alloy exceeds a maximum of 6.0%, as stated in the ADA specification, the resultant amalgam exhibits excessive expansion and a greater tendency to tarnish. These undesirable qualities or characteristics, based upon a copper content of greater than 6.0%, appear to be due, at least metallurgically, to the presence of Ag 5 Sn (beta phase) in the alloy microstructure. A correlation has been found to exist between the presence of such a beta phase and an uncontrollable (i.e., unrestricted) expansion of the amalgam. Further, the Ag 3 Sn (gamma) phase has a sulfide tarnish resistance greater than that found in silver-tin alloys containing higher amounts of silver (Ag 5 Sn-beta phase is such an alloy). Moreover, the basic silver-tin (gamma) phase has the highest physical strength properties of all the major components of the standard or conventional ADA dental amalgam, including the silver-mercury and tin-mercury, gamma-1 and gamma-2, phases. BRIEF DESCRIPTION OF THE INVENTION This invention relates to dental amalgams having improved resistance to corrosion, tarnish and inter-granular fracture. These desirable and beneficial results are achieved through the design of a two-component amalgam alloy system which, when the two components are combined and amalgamated with mercury, leads to the elimination of the corrodible tin-mercury (gamma-2) phase with a simultaneous reduction in the deleterious silver-mercury (gamma-1)phase. The improved dental amalgam system of this invention has as a further object and purpose the maintenance of an increased amount of the silver-tin (gamma) phase constituent in the microstructure of the standard or conventional dental alloy, in order to secure the benefit of its singularly excellent resistance to tarnish and corrosion and its superior physical properties, in the resultant amalgam restoration. At the same time the amalgam of this invention is free of the undesirable and highly corrodible tin-mercury (gamma-2) phase. Another object of the invention is to provide a second component alloy which readily amalgamates with mercury to provide the desired working quality or plasticity, and when combined and amalgamated with the cnventional first component silver-tin (Ag 3 Sn) alloy acts as an effective "getter" for the corrodible tin in the tin-mercury (gamma-2) phase. Yet another object of the invention is to provide a second component alloy for a dental amalgam having a sufficient oxidation resistance so that its exposure to ambient atmospheric conditions does not retard its amalgamation with the mercury. Still a further object of the invention is the reduction in the amount of silver required for the amalgam, presently relatively expensive, whereby the dental amalgam of this invention has considerable economic importance and advantage. DESCRIPTION OF PREFERRED EMBODIMENTS A dental amalgam of this invention is fabricated by trituration of a combination of two metallic components in particulate form with mercury, wherein the mercury content comprises from about 40 to 60% by weight of the combined two components. I The first of the component alloys of this mixture comprises the standard or conventional dental amalgam alloy, formulated within the composition limits stated by the current American Dental Association Specification No. 1, which makes up 70 to 90% of the mixture. Such alloy component, identified as the first component alloy, comprises, by weight: Silver 65.0% minimumTin 29.0% maximumCopper 6.0% maximumZinc 2.0% maximum According to European practice, mercury to 3.0% maximum may be added to the foregoing composition alloy. The remaining 10-30% of the mixture comprises one of the following copperbase alloys, as the second component alloy, preferably of but not necessarily limited to a particle size of 30 microns or less. a. The second component alloy is one of the coppersilver alloys containing more than 50% copper. These alloys will meet and satisfy the objectives of the present invention. However, to maintain the silver-mercury phase in the amalgam to a low level, the second component alloys should preferably contain not more than 20.00% silver. Again, these alloys are subject to oxidation under ambient conditions and may hinder amalgamation. However, it has been found that if the particle size of these alloys is maintained below 15 microns, such oxidation as may be present will not adversely affect the dental amalgam and the purposes and advantages for which the alloy is designed. b. Another second component alloy is one taken from the ternary and quaternary copper-base alloys containing silver, and/or tin, and/or zinc within the following composition limits (by weight): Copper more than 50.00%Silver 0 - 49.00%Tin 0 - 10.00%Zinc 0 - 5.00% The above broad range of composition includes the following alloy systems: b-1. Alloys comprising essentially copper-silver-tin in proportions of Silver up to and including 49.00% maximumTin up to and including 10.00% maximumCopper balance Preferred composition limits for these alloys are Silver up to and including 20.00% maximumTin up to and including 10.00% maximumCopper balance and a preferred example of such an alloy comprises essentially Silver 8.0% Tin 5.0% Copper Balance b-2. Alloys comprising essentially copper-silver-zinc in proportions of Silver up to and including 49% maximumZinc up to and including 5% maximumCopper balance and preferred composition limits for these alloys are Silver up to and including 20.0% maximumZinc up to and including 5.0% maximumCopper balance A preferred example of such an alloy comprises essentially Copper 93% Silver 5% Zinc 2% b-3. Alloys comprising essentially copper-tin-zinc in proportions of Zinc up to and including 5% maximumTin up to and including 10% maximumCopper balance A preferred range of composition for these alloys is Zinc up to and including 5% maximumTin up to and including 10% maximumCopper balance A preferred example of such an alloy is Copper 93% Tin 5% Zinc 2% b-4. Alloys containing copper-silver-tin-zinc in which the broad range of the elements is as follows: Copper more than 50.0%Silver up to and including 49.0% maximumTin up to and including 10.0% maximumZinc up to and including 5.0% maximum A preferred range for this combination of elements is Silver up to and including 20.0% maximumTin up to and including 10.0% maximumZinc up to and including 5.0% maximumCopper balance A preferred example of this quaternary alloy is Silver 5% Tin 3% Zinc 2% Copper 90% The presence of silver, tin and zinc in the above alloy systems described in sections (b) through (b-4) above facilitate the amalgamation of the second component which is required for the handling characteristics or workability of the amalgam. Furthermore, these elements impart corrosion resistance to the second component alloy to improve the corrosion resistance of the amalgam, since the set amalgam will always contain some unreacted second component alloy. Again, in view of their greater solubility (than that of copper) in mercury, these elements counteract such limiting effects as may be due to oxidation of the second component alloy that hinders amalgamation. c. An amalgamated second component alloy is one taken from the copper-base alloys containing silver, tin, zinc and mercury within the following broad range of composition: Copper more than 50%Silver 0 - 49%Tin 0 - 10%Zinc 0 - 5%, andMercury up to and including 20% maximum The above broad range of composition includes the following alloy systems: c-1. Alloys of copper-mercury containing at least 80% copper. An example of such an alloy contains 90% copper and 10% mercury. c-2. Alloys of copper-silver-mercury within the following broad composition limits: Silver up to and including 49% maximumMercury up to and including 20% maximumCopper balance Preferred composition limits for these alloys are Silver up to and including 20% maximumMercury up to and including 10% maximumCopper balance and a preferred example is Copper 90.0% Silver 5.0% Mercury 5.0% c-3. Alloys of copper, tin and mercury in the following broad composition limits Tin up to and including 10.0% maximumMercury up to and including 20.0% maximumCopper balance Preferred composition limits for these alloys are Tin up to and including 10.0% maximumMercury up to and including 10.0% maximumCopper balance A preferred example: Copper 90% Tin 5% Mercury 5% c-4. Alloys of copper, zinc and mercury within the following broad composition limits Zinc up to and including 5% maximumMercury up to and including 20% maximumCopper balance Preferred composition limits for these alloys are Zinc up to and including 5% maximumMercury up to and including 10% maximumCopper balance A preferred example of such alloy is Copper 93.0% Zinc 2.0% Mercury 5.0% c-5. Alloys of copper, silver, tin and mercury within the broad composition limits - Silver up to and including 49% maximumTin up to and including 10% maximumMercury up to and including 20% maximumCopper balance Preferred composition limits for these alloys are Silver up to and including 20% maximumTin up to and including 10% maximumMercury up to and including 10% maximumCopper balance A preferred example of such alloy is Copper 90.0% Silver 3.0% Tin 2.0% Mercury 5.0% c-6. Alloys of copper, silver, zinc and mercury within the broad composition limits Silver up to and including 49% maximumZinc up to and including 5% maximumMercury up to and including 20% maximumCopper balance Preferred composition limits for these alloys are Silver up to and including 20% maximumZinc up to and including 5% maximumMercury up to and including 10% maximumCopper balance A preferred example of such alloy is Copper 90.00% Silver 3.00% Zinc 2.00% Mercury 5.00% c-7. Alloys of copper, tin, zinc and mercury within the broad composition limits Tin up to and including 10% maximumZinc up to and including 5% maximumMercury up to and including 20% maximumCopper balance Preferred composition limits for such alloys are Tin up to and including 10% maximumZinc up to and including 5% maximumMercury up to and including 10% maximumCopper balance A preferred example of such alloy is Copper 90.0% Tin 3.0% Zinc 2.0% Mercury 5.0% c-8. Alloys of copper, silver, tin, zinc and mercury within the broad composition limits Silver up to and including 49% maximumTin up to and including 10% maximumZinc up to and including 5% maximumMercury up to and including 20% maximumCopper balance Preferred composition limits of such alloys are Silver up to and including 20% maximumTin up to and including 10% maximumZinc up to and including 5% maximumMercury up to and including 10% maximumCopper balance A preferred example of such alloy is Copper 90.0% Silver 3.0% Tin 1.0% Zinc 1.0% Mercury 5.0% Such preamalgamated alloys included in the systems described in (C) through (C-8) above, in addition to having the advantages and benefits of the unamalgamated second component alloys of the systems described in (b) through (b-4) above, offer the further advantage of ease and speed in amalgamation of the mixture with mercury. An alloy formulated within the limits of the compositions described in (a), (b) through (b-4) and (c) through (c-8) above for the second component alloy, will satisfy the objectives and purposes for which the invention is designed. However, for the silver-containing second component alloys in (a), (b) through (b-4) and (c) through (c-8) above, the silver content is preferred on the low side rather than the high side of the range in order that the amount of the silvermercury (gamma-1) phase in the microstructure be held to a low level. The preferred silver content should not exceed 20.0% as has been indicated in the preferred ranges of compositions for those alloys which contain silver. In the context of the disclosure in this application, the term "copper-base alloy" is to be understood to mean an alloy containing more than 50.0% copper by weight. Both the first and second component alloys of the present invention may be supplied in the form of atomized powders, lathe-cut particles, filings, or tablets made therefrom. Although particular embodiments of the invention have been disclosed herein for purposes of explanation, further modifications or variations thereof, after study of this specification, will or may become apparent to those skilled in the art to which the invention pertains. Reference should be had to the appended claims in determining the scope of the invention.	A two-component amalgam alloy system comprises as a first component a standard silver-tin amalgam alloy, and as a second component a copper base alloy. The two components are intermixed and amalgamated with mercury to form a dental amalgam from which the highly corrodible tin-mercury (gamma-2) phase has been removed and the readily tarnishable and inter-granular fracturable (brittle) silver-mercury (gamma-1) phase can be reduced.	2
FIELD OF THE DISCLOSURE The present disclosure relates generally to systems for transporting articles in an industrial setting. More particularly, the present disclosure is directed toward a self-lubricating, overhead conveyor system and the component parts thereof. BACKGROUND It is common in industrial settings to employ overhead conveyor systems to move articles from point to point, as may be required in many industrial applications. These overhead conveyor systems typically include an overhead track system, several trolley assemblies, a conveyor chain to join and drive the trolley assemblies along the track and turn wheel assemblies to guide the conveyor chain. The trolley assemblies have attached hangers which extend below the track to transport the desired articles along the track. The typical overhead conveyor systems described above, while useful, suffer from several disadvantages. First, the various components of the trolley wheel systems require significant amounts of maintenance. If the components of the trolley wheel systems are not maintained properly, the system will not operate at optimal levels. As one example of required maintenance, most trolley wheel assemblies require that additional lubrication be added from time to time (the additional lubrication itself presents some problems as discussed below). The lubricant helps decrease component part wear, at least partially, by decreasing the coefficient of friction associated with the operation on the conveyor system. If the addition of lubrication is ignored, the coefficient of friction will increase, placing increased stress on the component parts, which may lead to system failure. For example, if lubrication maintenance is not performed, the friction generated by the trolley assemblies will increase. This increases the resistance the conveyor system encounters and places stress on the components of the conveyor system, as well as increasing the energy required to operate the conveyor system. Likely results will be an increase in the chain pitch (or chain length) and/or premature chain failure. If the chain pitch is increased enough, the timing of the system may be impacted, causing defects in the associated industrial processes. In either case, the conveyor system and its associated industrial process must be stopped so that sections of chain can be removed to restore the original pitch to the chain or a new chain installed. The maintenance problems are exacerbated when the trolley wheel systems are required to function in harsh environments. In these situations, the maintenance requirements for trolley wheel systems may be further increased. As stated above, adding additional lubricants to overhead conveyor systems presents significant problems. The additional lubrication will drop from the trolley wheel system during operation, and potentially contaminate the articles carried by the trolley wheel system. The added lubricant may mix with rust that has developed on the components of the conveyor system as well, bringing additional contaminates into contact with the articles carried by the system. This phenomenon is so common in some industries (such as the poultry processing industry), it is known as “rail dust,” which is sometimes referred to as “black rain.” Finally, the individual components of the conveyor systems are not engineered as a unit to maximize the operation and longevity of the system. As discussed above, increased friction, caused by the design of the individual components and inadequate lubrication, may cause changes in the chain pitch. Solutions to this problem have been to design trolley wheel assemblies with improved lubrication properties. However, these solutions only address part of the underlying issue. For example, a conveyor chain with improved resistance to changes in pitch could be combined with a trolley wheel assembly with improved properties, to improve the operation of the conveyor system as a whole. Such a synergistic approach has been lacking. The present disclosure provides such an approach to describe an improved overhead conveyor system and the component parts thereof. SUMMARY The present disclosure describes a self-lubricating, overhead conveyor system and the component parts thereof. The conveyor system has a primary application in the manufacturing and food processing fields, but is suitable for use in any application that requires the movement of articles from point to point. The overhead conveyor system comprises three main components, a trolley assembly, a conveyor chain and a turn wheel assembly. In one embodiment, all three components are integrated to provide an improved overhead conveyor system. In an alternate embodiment, individual components as described, alone or in various combinations, are used to retrofit conventional overhead conveyor systems to increase the performance of these systems. In operation, a plurality of trolley assemblies are configured to be removably coupled to a track system, such as an I-beam track, suspended above the ground. The individual trolley assemblies are joined together by the conveyor chain. The conveyor chain is propelled down the track by a drive means, such as a conventional drive assembly, or other device. A conventional drive assembly comprises a drive motor a reducer and drive sprockets to engage the conveyor chain. Typically, several drive assemblies are used per conveyor system. The turn wheel assemblies are located at predetermined locations along the suspended track and are configured to engage the conveyor chain. The turn wheel assemblies function to maintain the trolley assemblies and the conveyor chain in the correct orientation when the conveyor system changes direction, and to provide lubrication to the conveyor chains and to clean the conveyor chains. In one embodiment, the trolley assemblies are self-lubricating, thereby eliminating the need for additional lubrication. The trolley assemblies are joined together by a surface hardened conveyor chain internally treated to resist corrosion and eliminate flaking. The turn wheel assemblies are configured to engage the conveyor chain and provide continuous lubrication and cleaning to the conveyor chain, eliminating the need for added lubrication. All components of the conveyor system of the present disclosure meet criteria established by the United States Department of Agriculture (USDA) for use in food processing applications. Therefore, it is an object of the disclosure to provide a self-lubricating conveyor system. The self-lubricating conveyor system reduces drag and the coefficient of friction of the conveyor system, reducing the wear to the components of the conveyor system and increasing the life of the conveyor system. It is a further object of the disclosure to provide a trolley assembly comprising a lubricating element to eliminate the need for added lubrication to the trolley assembly. An additional object of the disclosure is to provide a trolley wheel where the lubricating element provides a barrier to reduce contamination of the trolley assembly. An additional object of the invention is to provide a conveyor system that reduces potential contamination caused by added lubricants, sometimes referred to as “rail dust.” It is a further object of the disclosure to provide a conveyor system that has an increased useful life and requires less maintenance than conventional conveyor systems. An additional object is to provide a trolley assembly that eliminates the possibility of pre-loading the trolley wheel assembly. It is a further object of the invention to provide a conveyor system that meets all applicable U.S.D.A. regulations and requirements and is suitable for use in food processing operations. The above stated objects of the invention are alternative and exemplary objects only, and should not be read such that all objects and advantages are required for the practice of the invention in every embodiment described. The above objects and advantages are neither exhaustive nor individually critical to the spirit and practice of the invention. Other or alternative objects and advantages of the present invention will become apparent to those skilled in the art from the following description of the invention. BRIEF DESCRIPTION OF THE FIGURES FIG. 1 shows one embodiment of the overhead conveyor system of the present invention, illustrating the interaction of the trolley wheel assembly with an I-beam track; FIG. 2A shows a front view of one embodiment of the trolley wheel; FIG. 2B shows a side view of one embodiment of the trolley wheel; FIG. 3 shows a partially exploded side view of the trolley wheel assembly detailing the interaction of the fastening means with the trolley wheel; FIG. 4A shows a cutaway view of one embodiment of the ball bearing assembly; FIG. 4B shows the interaction of the fastening means with the trolley wheel and the ball bearing assembly; FIG. 5 shows a partially exploded side view of one embodiment of the conveyor chain; FIG. 6 shows a side view of one embodiment of the conveyor chain interacting with the trolley wheel assembly; FIG. 7 shows a partially exploded side view of one embodiment of the turn wheel assembly; FIG. 8A shows one embodiment of the tooth profile of the individual teeth comprising the tooth segments of the turn wheel assembly; and FIG. 8B shows an alternate embodiment of the tooth profile of the individual teeth comprising the tooth segments of the turn wheel assembly. DETAILED DESCRIPTION Trolley Assembly The trolley assembly 10 of the present disclosure is adapted for use with an I-beam track 50 of conventional design as shown in FIG. 1 . The track 50 comprises a support 52 with two laterally inclined flanges 54 to support and guide a plurality of trolley assemblies 10 . In one embodiment, each trolley assembly 10 comprises a pair of trolley wheels 100 , each wheel 100 removably coupled to a trolley bracket 150 by a fastening means, illustrated in FIG. 1 as bolt 180 and bushing 182 . Each trolley wheel 100 further comprises a self-contained ball bearing element 200 . The trolley brackets 150 are of standard design and comprise an angular upper portion 152 and a depending flanged portion 154 . The angular upper portion 152 forms a recess to receive the trolley wheels 100 in a manner so that trolley wheels 100 can engage the lateral flanges 54 of the track 50 . Two trolley brackets 150 are removably secured together at apertures 154 at 156 and 158 by bolts or other means. Flanges 154 comprise a notched portion 160 between 156 and 158 to receive the conveyor chain 300 (as described below). Sandwiched between the flanges 154 is a hanger bracket 162 to receive a hook 164 to support the load carried by the trolley wheel assemblies 10 . The trolley wheel 100 comprises a front side 102 , a back side 104 and an outer peripheral surface 106 adapted to engage the track 50 (see FIG. 2 A and FIG. 2 B). The peripheral surface 106 joins the front side 102 and back side 104 of wheel 100 . The rear side 104 contains a chamber 110 adapted to receive the bearing element 200 . The chamber 110 is of sufficient dimensions to receive the bearing element 200 , with the exact dimensions depending on the configuration of bearing element 200 and the material composition of the trolley wheel 100 . In one embodiment, the radius of the chamber 110 is in the range of 39.5 to 41.5 millimeters. A radius of 40.0 millimeters will receive a bearing element 200 such that the bearing element 200 will not separate from the trolley wheel 100 (when the trolley wheel 100 is manufactured from Delrin® and assembled as discussed below). In addition, a cover 185 may be sonically welded over the chamber 110 to further prevent separation of the bearing assembly 200 from the trolley wheel 100 . The cover 185 also serves as a barrier to prevent against contamination of the trolley wheel 100 and the bearing assembly 200 . The front side 102 contains an opening 108 to receive the fastening means (bolt 180 and bushing 182 ). The outer peripheral surface 106 may be designed to incorporate an angle (as shown in FIG. 2 B). The angle functions to improves transit of the trolley wheel 100 along the track 50 by reducing drag, and allows the trolley wheel 100 negotiate turns in the track 50 more efficiently. In one embodiment the angle of the outer peripheral surface ranges from 5 to 15 degrees as measured from the back side 104 to the front side 102 . In an alternate embodiment, this angle is 7 degrees. The width of the trolley wheel 100 is less than conventional trolley wheels. In one embodiment, the width of the outer peripheral surface 106 of the trolley wheel 100 is approximately 19 millimeters (FIG. 2 B). The decreased width of trolley wheel 100 further decreases the coefficient of friction of the trolley wheels 100 against the track 50 . Conventional trolley wheels were designed with increased width in order to increase the load bearing capacity of the trolley wheel. As discussed below, due to the novel bearing assembly 200 and fastening means incorporated into trolley wheels 100 , load capacities can be increased without increasing the width of the trolley wheels 100 . The trolley wheel 100 is manufactured from a polymer material. In one embodiment, any resin marketed under the Delrin® series trade name (Delrin® trademark registered to E. I. du Pont de Nemours and Company; properties of Delrin® are described in technical literature accessible at www.dupont.com:8501/custom/plastics1/) is used as the polymer. One example is the acetyl homo-polymer form of Delrin® is used as the polymer. However, other polymers can be used, including, but not limited to, ultra-high molecular weight (UHMW), polypropylene, polyethylene or Teflon. Suitable polymers may exhibit resistance to compression, low drag characteristics and be able to function efficiently in a wide range of environmental conditions, as well be resistant to chemical reagents used in cleaning and maintenance of conveyor systems. The design of the trolley wheel 100 (in combination with the bushing 182 and cover 185 ) is designed to act as a protective shield against contamination of the ball bearing assembly 200 . The fastening means comprises a bolt 180 and bushing 182 . The bushing 182 is manufactured from a polymer material to resist compression. The polymer material may be the same polymer material used in the construction of the trolley wheels 100 , although other polymer materials may also be used. The bushing may be glass fibre filled to further resist compression. In one embodiment, the bushing is in the range of 15-35% glass fibre filled. The bushing 182 is configured with a crown 184 adapted to interact with opening 109 of the cover 185 and opening 214 of the bearing assembly 200 to allow self-adjustment of the trolley wheel 100 (FIG. 3 ). This self-adjustment allows the trolley wheel assemblies 10 to negotiate turns in track 50 without undergoing compression or impinging on track 50 , which can lead to increased friction and drag, thereby reducing the efficiency of the conveyor system and increasing the stress applied to the components of the conveyor system. In addition, the bushing 182 has a back portion 186 . One function of the back portion 186 is to provide separation of the back side 104 of the trolley wheel 100 with the trolley bracket 150 . If the length of the back portion 186 is not sufficient, then trolley bracket 150 will impact the back side 104 of the trolley wheel 100 , damaging the wheel. In one embodiment, the length of the back portion 186 is in the range of 8-12 millimetres. A length of 10.5 millimetres for back portion 186 is sufficient to allow for compression caused by the tightening of bolt 180 and prevent trolley bracket 150 from contacting the back side 104 . Bolt 182 can be manufactured from a variety of materials, including stainless steel and carbon steel. In one embodiment, the bolt 182 is manufactured from carbon steel that is treated to resist corrosion (as described below for the conveyor chain). Bolt 182 has a bolt head 190 . The bolt 182 is placed through opening 108 of the trolley wheel 100 , opening 214 of the bearing assembly 200 and opening X of the trolley bracket 150 . The bolt head 190 rests against the inner race 202 of the bearing assembly 200 . The bolt 182 is secured by a nut 192 . As the nut 192 is secured on bolt 182 , the bushing 180 is compressed and bolt head 192 is tightened against the inner race 202 . In this manner, bolt head 190 clamps inner race 202 in place, preventing the inner race 202 from free rotation about the axis of bolt 182 . The bolt head 190 is designed so that it does not extend past the plane formed by the front side 102 . In one embodiment, the bolt head 190 is not greater than ⅛ inch thick. If the bolt head 190 does extend beyond the plane formed by the front side 102 , the bolt head 190 may contact the support 52 or flanges 54 of track 50 , created metal to metal contact. This contact increases the coefficient of friction and creates contamination. The ball bearing assembly 200 comprises an inner race 202 and an outer race 204 joined together by a floor 206 (FIG. 4 A). The inner race 202 , outer race 204 and floor 206 define a raceway 208 to receive the balls 210 . The floor 206 may contain a channel to provide a groove in the raceway 208 through which the balls 210 may travel. The bearing assembly 200 is a self contained unit that is incorporated into the trolley wheels 100 at cavity 110 . The inner race 202 and the outer race 204 are of unitary construction. Conventional trolley wheel assemblies traditionally utilize a two piece inner race assembly. The inner race serves several purposes in the trolley wheel. First, the inner race provides a shoulder for the fastening means that couples the trolley wheel to the trolley bracket. Second, the inner race defines a portion of the raceway for the rotation of the balls in the bearing assembly. By increasing or decreasing the torque applied to the fastening means, the internal clearance of the raceway in a two-piece inner race assembly can be altered (as the relative positions of the components of the 2-piece inner race are changed) to the point that the balls no longer have a free rotation in the raceway. This creates what is known as a pre-loading condition. The pre-loading condition affects the inertia of movement of the trolley wheel, requiring additional torque to rotate the trolley wheel (this condition is referred to as drag). In the present disclosure, the trolley wheels 100 are secured to the trolley brackets 150 by a fastening means, illustrated in FIGS. 1 and 4B as bolt 180 and bushing 182 . The bolt 180 is designed such that the head 190 and the crown 184 of the bushing 182 contacts only the inner race 202 of the bearing assembly 200 (FIG. 4 B). Since the inner race 202 is of unitary construction, altering the torque of the fastening means will not result in a pre-load condition. In addition, in conventional trolley wheels, the outer race is often an integral portion of the trolley wheel itself, comprising a stainless steel band attached directly to the inner portion of the trolley wheel. Since the outer race is an integral part of the trolley wheel, movement of the trolley wheel could also alter the internal clearance of the raceway, leading to the problems described above. As a result, conventional trolley wheels have a measured inertia of approximately 0.014 Vs. Due to the self-contained nature of the bearing assembly 200 and the self-lubricating properties of the trolley wheels 100 , the trolley wheels 100 of the present disclosure have a measured inertia of approximately 0.001 Vs. In one embodiment, the bearing assembly 200 is not fully loaded, meaning that the balls 210 are separated by bearing cages (sometimes referred to as spacers) 212 (FIG. 4 A). Conventional trolley wheel assemblies generally incorporate full complement, non-precision balls. The full complement state, while decreasing the cost of the bearing assembly and increasing the load the bearing assembly can support, leads to increased friction being generated as the balls interact with one another and decreased speeds of travel for the trolley wheel assemblies. The use of a non-full complement state in bearing assembly 200 eliminates these difficulties. A further improvement is directed towards the balls 210 of the bearing assembly 200 . The bearing assembly 200 incorporates precision ground balls. In one embodiment, ABEC 1 standard precision ground stainless steel balls are used. The used of precision ground balls 210 leads to the elimination of the increased friction and drag created when non-precision ground balls are used (as in conventional trolley wheel assemblies). In addition, bearing assembly 200 may incorporate a groove to guide the balls 210 in raceway 208 . The use of a non-full complement state combined with the use of precision ground balls 210 and groove in bearing assemblies 200 increases the performance of the trolley assemblies 10 over conventional trolley wheel assemblies. The trolley wheel assemblies 10 of the present disclosure also comprise a self-lubricating means, shown as cured graphite mixture 24 in FIG. 4 A. As a result, the trolley wheel assemblies 10 do not require additional lubrication over their lifetime. In one embodiment, a mixture of liquid graphite is poured into the raceway 208 of the bearing assembly 200 . The graphite mixture encapsulates the balls 210 and the bearing cages 212 , filling substantially all of the raceway 208 (FIG. 4 A). The liquid graphite material comprises a mixture of graphite and phenolic resin, although other mixtures can be used, including but not limited to, graphite and MOS. The bearing assembly 200 with the added liquid graphite is then heated in a furnace to cure the liquid graphite. Typical temperature ranges for heating are from about 250 degrees Fahrenheit to about 650 degrees Fahrenheit. The curing time for the liquid graphite is about 1-6 hours. The tumbling of the balls 210 against the cured graphite 24 or other lubricating means allows lubricant to leach out over time, continuously lubricating the balls 210 . Once cured, the graphite 24 becomes a permanent part of the bearing assembly 200 and provides permanent lubrication to the bearing assembly, obviating the need for added lubricants. The cured graphite 24 is inherently more stable than petroleum lubricants and has a much lower coefficient of friction. The reduced coefficient of friction is due in large part to the reduction in inertia drag created the bearing assembly 200 begins to rotate. When petroleum based lubricants are used in conventional bearing, the inertia drag is created by the channelling effect as the balls must create a path through the petroleum lubricant. In the current disclosure, the cured graphite moves with the balls 210 , virtually eliminating inertia drag and reducing the coefficient of friction. In the bearing assembly 200 of the present disclosure, increased loads can be tolerated because of the reduced coefficient of friction created by the design of the bearing assemblies 200 as discussed above. Due to the fact that the bearing assembly 200 can sustain increased loads, the width of the trolley wheel 100 can also be decreased, as discussed above. Conventional trolley assemblies generally incorporate oil or grease lubricants which, after time, loose their effectiveness requiring that additional lubricants be added. The added lubricants are liquids which escape from the trolley wheels and accumulate on the track and the trolley brackets, where the added lubricants mix with rust and other contaminants. This mixture of added lubricants and contaminates then drops onto the articles carried by the overhead conveyor system. In the poultry industry, this phenomenon is referred to as “rail dust.” In addition to providing a lubricating function, the cured graphite 24 forms a seal, preventing dust, powders, and micro-particle contaminant from entering the bearing assembly 200 and clogging the raceway 208 . In addition, the seal prevents corrosion of the balls 210 and bearing cages 212 that may be caused by cleaning solutions and contaminants. Unlike commonly used petroleum based lubricants, the cured graphite 24 will not be washed out of the bearing assembly 200 by steam, solvents, acids or alkalis used to clean the overhead conveyor systems. In addition, the cured graphite 24 exhibits virtually no out gassing when used in vacuum applications. The cured graphite 24 functions in a wide range of operating conditions without significant changes in starting torque or lubricity (as described above). The cured graphite has an operating range of about −250 degrees Fahrenheit to about 650 degrees Fahrenheit. The trolley assemblies 10 represent a significant advance over conventional trolley assemblies for use on overhead conveyor systems by virtue of the design of trolley wheels 100 , the use of self-lubricating bearing assembly 200 and the fastening means (bolt 180 and bushing 182 ). First, the trolley assemblies 10 obviate the need for additional lubrication. This decreases the maintenance time and cost associated with currently available overhead conveyor systems. In addition, the trolley wheels 100 of the present disclosure reduce the coefficient of friction by approximately 50%. Existing trolley wheels using the currently available forms of lubrication have a coefficient of friction in the range of 0.049. However, the trolley wheels 100 of the present disclosure have a coefficient of friction in the range of 0.026. As a result of decreasing the coefficient of friction of the trolley wheels 100 , the stress applied to the components of the overhead conveyor system is decreased, thereby increasing the life of the components of the system. For example, the life of the conveyor chain 300 is increased by decreasing the stress placed on the conveyor chain 300 as a result of the reduced coefficient of friction applied by the trolley wheel assemblies 10 . Conveyor Chain The conveyor chain 300 comprises a series of split halves 302 A and 302 B, the split halves being joined together by a fastening means, illustrated as I-pin connector 304 to form links 306 (FIG. 6 ). The split halves 302 A and 302 B and the I-pin connector 304 define at least one cavity 307 in each link 306 . The links 306 of chain 300 are separated by center link 308 , which is sandwiched between the split halves 302 A and 302 B and is also secured to the split halves 302 A and 302 B by I-pin connector 304 as illustrated in FIGS. 5 and 6 . The distance between the centers of adjacent cavities 307 is referred to as the chain pitch. The chain pitch for most chains used in industrial processes (such as the poultry industry) is 76.5 millimetres. Central link 308 of chain 300 engages the trolley brackets 150 at notch 160 on flanges 154 (see FIG. 1 and FIG. 5 ). In this manner, a plurality of trolley wheel assemblies can be joined together by chain 300 to drivingly engage the trolley wheel assemblies 10 down the track 50 of the overhead conveyor system. The chain 300 may be constructed from a variety of materials. In one embodiment, chain 300 is manufactured from cold haul quality (CHQ) steel, however other materials can be used, including, but not limited to micro-alloy steel. The I-pin connector 304 can also be made from CHQ steel. The chain 300 and I-pin connector 304 is surface hardened to about 75 Rockwell to resist stretching/changes in chain pitch, which can lead to timing errors in the conveyor system. In addition, the chain is impregnated with silicon nitride to resist corrosion and to prevent flaking that occurs in conventional chains that are simply plated with anticorrosion materials, such as zinc. The flaking off of plating materials can contaminate the environment, including the articles transported by the overhead conveyor system. In addition, areas where the plating material has been removed can provide unprotected areas that may lead to rust, corrosion and deterioration, providing a further source of contamination and decreasing chain life. In the treatment process, the components of the chain 300 are hardened at approximately 1600 degrees F. and quenched in oil to temper. The parts of chain 300 are then placed in a furnace and covered with sand. The parts of chain 300 are heated to slightly below the tempered heat (ranging from 25-50 degrees F. below the tempered heat), which is approximately 1050-1150 degrees F. The sand bed is then injected with gasses containing silicon nitride and subject to vibration. As a result, the chain components pass through the sand bed. During this process two layers are formed, a first inner layer termed the white layer and a second outer layer which is ceramic in nature. The second layer is supported by a chemically enhanced diffusion zone and is ceramic in nature. During this process, the chain is also “lapped” which removes burrs and rough edges. This reduces the knifing effect often seen in conveyor chains as the rough edges of the chain components interact with one another. The second outer layer reaches a hardness of approximately 75 Rockwell and exhibits a microporosity that when quenched in H1 or H2 oil further protects the components of chain 300 and increases their lubricity during the chain wear in. The strength of chain 300 , in addition to resisting changes in pitch and the problems associated therewith, allows the conveyor system to operate at an increased tension. As a result, trolley wheel assemblies 10 can be placed on 12 inch centers, rather than 6 inch centers. In conventional conveyor systems, when trolley wheel assemblies were placed on 12 inch centers, the conveyor chain sagged in the middle, causing problems with chain timing and the industrial processes associated therewith. Conventional chains lacked the strength to be placed under sufficient tension to make the use of 12 inch centers feasible. By using 12 inch centers, the number of trolley wheel assemblies can be reduced by half, decreasing the cost of the system and simplifying operation. Turn Wheel Assembly The turn wheel assembly 400 functions to guide the conveyor chain 300 by maintaining the chain 300 in the vertical plane when the overhead conveyor system changes direction (FIG. 7 ). In one embodiment, the turn wheel assembly 400 a solid disk of material, such as UHMW. A groove 402 is machined in the disk of material, creating an upper shelf 404 A above the groove 402 and a lower shelf 404 B below the groove 402 (FIG. 7 ). The groove 402 is created such that the internal arc has an internal dimension to receive a plurality of tooth segments 406 such that the tooth segments 406 can interact with the links 306 of chain 300 . The internal dimension of the arc 402 will vary depending on the diameter of the turn wheel 401 . In one embodiment, the turn wheel 401 has a diameter of 19 inches and the internal arc of groove 402 has a diameter of 13.125 inches (334.4 millimetres). When the turn wheel 401 has a diameter of 24 inches, the internal arc of groove 402 has a diameter of 14.750 inches (374.7 millimetres). The exact dimensions of the groove 402 will depend on the configuration of the tooth segments 406 , and such modifications are within the ordinary skill in the art. The tooth segments 406 are removably secured in place by a securing means, illustrated as bolt 408 A and nut 408 B. The securing means pass through the upper shelf 404 A, the tooth segments 406 and the lower shelf 404 B. The securing means exert a clamping effect on tooth segments 406 such that a force is applied to the tooth segments 406 that push the tooth segments outward. This force combats the force that will be applied to the tooth segments 406 as they interact with chain 300 , which is typically in the range of 30 ft/lbs. Each tooth segment 406 comprises at least one tooth. In one embodiment illustrated in FIG. 7 , each tooth segment 406 comprises 2 teeth 410 A and 410 B. The individual teeth are spaced a distance apart so that each tooth on tooth segment 406 engages each link 306 of chain 300 so that each tooth is inserted in a cavity 307 . In the embodiment illustrated in FIGS. 6-8 , the individual teeth 410 A and 410 B are spaced approximately 76.5 millimetres apart, with the same spacing being maintained between individual teeth on adjacent tooth segments 406 . This distance corresponds with the chain pitch of the conveyor chain 300 described herein. The distance between teeth can be varied to adapt to chains with different pitches, with such modification being within the ordinary skill in the art. Each tooth segment 406 may comprise a greater or lesser number of individual teeth, so long as the spacing of the individual teeth is such that each tooth on tooth segment 406 engages each link 306 of chain 300 so that each tooth is inserted in a cavity 307 . The number of tooth segments 406 per turn wheel assembly 400 can also be varied, depending on the diameter of the turn wheel 400 . In the embodiment illustrated in FIG. 7 , the turn wheel assembly can accommodate 5 tooth segments 406 . The number of individual tooth segment 406 per turn wheel 400 can be varied as long as the spacing of the individual teeth is such that each tooth on tooth segment 406 engages each link 306 of chain 300 so that each tooth is inserted in a cavity 307 . The individual teeth comprising the tooth segments 406 are designed with a profile to maximize the insertion of the individual teeth into cavity 307 of the links 306 . In one embodiment, the individual teeth 410 A and 410 B are rounded at their periphery 412 , to produce stub tooth design (FIG. 8 A). The stub tooth design interacts with cavity 307 of link 306 in a fluid fashion and minimizes the contact of the outer periphery 412 of the individual teeth with the components of the chain 300 , which can result in cupping of the individual teeth. The cupping effect is the result of the links 306 of the conveyor chain 300 contacting the teeth in a manner so that the individual teeth do not cleanly engage cavity 307 of link 306 , but instead contact the components of the chain 300 , such as the split halves 302 A and 302 B, as they are inserted into cavity 307 . Such a situation can occur when slack is introduced in the chain 300 (effectively changing the chain pitch), or when the conveyor chain timing is not in register with the turn wheel. Although the chain 300 eliminates almost all stretching of chain 300 , when turn wheel assemblies of existing overhead conveyor systems that do not use chain 300 are retrofitted with tooth segments 406 of the present disclosure (as discussed below), such stretching of the conveyor chains may, and often does, occur. The stub tooth design eliminates the cupping problems caused by chain stretching and incorrect timing, as the components of the conveyor chain slide against the rounded outer periphery 412 of the individual teeth with less contact than when the individual teeth incorporate a drive tooth design (FIG. 8 B). In addition, since the outer periphery 412 of the individual teeth 410 A and 410 B is symmetrical, when one face of the outer periphery of the individual teeth becomes worn, the tooth segment can be removed and orientation of the tooth segments 400 in the turn wheel assembly can be reversed, extending the useful life of the tooth segments 406 . Although the stub tooth design described above offers certain advantages, other configurations of the individual teeth may be employed in the present disclosure. An alternate embodiment of the design of the individual teeth comprising the tooth segments 406 is shown in FIG. 8 B. In this embodiment, the individual teeth 410 C and 410 D of tooth segment 406 have a roughly triangular, or drive tooth, design. The teeth 410 C and 410 D are spaced as described above for teeth 410 A and 410 B, and the same variations described above apply. The tooth segments 406 (regardless of the design of the individual teeth) are formed from a capillary polymer material. The capillary polymer material is extruded and then molded into the desired tooth segment configuration (described above). The polymer material has an internal honeycomb structure that is impregnated with an USDA approved lubricant. In one embodiment, this lubricant is H2 oil, however other lubricants may be used, including, but not limited to H1 oil. The lubricant is introduced into the polymer mixture before it is extruded so that the lubricant is substantially uniformly incorporated into the structure of the polymer material. In one embodiment, the method for producing the polymer material comprises hand-packing the polymer material (with added lubricant) into an appropriate mold. Once the mold is secured the polymer material is baked in an oven at approximately 350 degrees F. to cure. The polymer is removed from the mold and allowed to air cool. In one embodiment, the polymer is cast into blocks for each tooth segment. The blocks are then machined to produce the desired configuration for the individual teeth to produce the finished tooth segment 406 . In another embodiment, the individual teeth can be molded in their desired configuration to produce the finished tooth segment 406 . As the individual teeth of the tooth segments 406 interact with the chain 300 , heat is generated as a result of friction between the teeth and components of chain 300 . As a result of the design of the individual teeth and the chain 300 , the outer periphery of the individual teeth contact the interior of the cavity 307 (composed of split halves 302 A and 302 B) and the base of the tooth segment contacts the sides of the chain (as illustrated in FIG. 8 for teeth incorporating the stub tooth design). If desired, turn wheel assemblies 400 can be placed on opposite side of the chain 300 to ensure that the tooth segments 400 contacts the maximum area of chain 300 . The change in temperature causes the lubricant trapped inside the honeycomb structure of the polymer to be released during use. As a result, the tooth segments 406 of turn wheel assembly 400 apply a constant light film of lubricant to the chain 300 , especially the components of the links 306 . This makes the turn wheel assembly 400 an automatic lubricating device in addition to its other functions. The stub tooth design of the individual teeth assures that the lubricant is applied to a substantial portion of the chain 300 . This coating of lubricant deters rusting or corrosion and provides a protective barrier to chain 300 . In addition, the insertion of the individual teeth of the tooth segments 406 into cavity 307 removes any existing rust and corrosion that may be present on the chain 300 . As a result, the useful life of the chain 300 is increased and the maintenance required is reduced. Since the chain 300 is constantly lubricated, the need for additional chain lubrication is obviated, reducing the possibility that lubricant will come into contact with the items carried by the conveyor system and reducing the occurrence of “rail dust” and similar phenomenon. When the lubricant is released from one or more honeycomb structures, the honeycomb structure collapses, and the residual polymer is removed by the friction between the chain 300 and the individual teeth on the tooth segments 406 . Since the polymer material is comprised of an essentially homogenous honeycomb structure, lubricant continues to be release from successive honeycomb structures. As a result of continuous lubrication, the tooth segments 406 have a finite service life. In prototypes used by Applicant, the tooth segments 406 have a life of approximately 7 months. The life to the tooth segments 400 is dependent on line tension and line speed, with the 7 month life based on an average chain speed of 78 RPM. The turn wheel assembly 400 is designed so that individual tooth segments 406 may be easily replaced as desired without removing the entire turn wheel assembly 400 , and without replacing the entire turn wheel assembly 400 . For replacement, the securing means, in this embodiment bolt 408 A and nut 408 B, a removed, a new tooth segment 406 inserted and the securing means reinserted. Conventional turn wheel assemblies generally do not employ tooth segments as does the turn wheel 400 of the present disclosure. Instead, conventional turn wheel assemblies employ a smooth material on the surface of the turn wheel assembly that contacts the chain. In other words, conventional turn wheel assemblies function only to keep the chain in the correct plane. Tooth segments 406 are designed so that conventional turn wheel assemblies may be retrofitted with the tooth segments 406 of the present disclosure. Through such retrofitting, the conventional turn wheel assemblies are converted into automatic lubricator, with the advantages discussed above. Advantages The components of the overhead conveyor system of the present disclosure offer maximal benefit when all the components described, the trolley assembly 10 , the conveyor chain 300 and turn wheel assembly 400 , are incorporated. However, it is within the scope of this disclosure that the individual components may be incorporated (either alone or in various combinations) into existing overhead conveyor systems, thereby improving the performance and extending the life of the existing overhead conveyor systems. As one example, and not meaning to exclude additional examples, the tooth segments 406 may be solely incorporated into existing turn wheel assemblies as discussed above. As discussed in this specification the use of the conveyor system of the present disclosure significantly extends the overall life of the conveyor system and decreases the maintenance costs associated with the system. These factors result in significant costs savings to the operator of the overhead conveyor system. An example of the cost savings using the overhead conveyor system of the present disclosure makes this point. The following example uses USDA average numbers for existing overhead conveyor systems. A typical conveyor system has a chain length of 600 feet. The average life of a chain is approximately 14 months, with the cost of the chain being $20 per foot, plus $2,400 for installation of the track (based on 30 man hours/installation at $80/man hour). Under normal operating conditions, an average overhead conveyor system processes 91 birds per minute. The cost/foot of conveyor chain 300 is $59.95. In order to compare the cost of the conveyor chain 300 to the average cost of conventional conveyor chains, the increased life and decreased maintenance cost of the conveyor chain of the present disclosure must be taken into account. The conveyor chain 300 has an estimated life of approximately 42 months, or 3 times the average life of conventional conveyor chains. Taking into account the fact that three conventional chains (at $20/foot) must be used to equal the expected life of chain 300 , the base cost of conventional conveyor chains is $60/foot. Adding the manpower cost to replace the conveyora chain 2 times ($4,800, at a cost of $2,400/installation) the cost of the average 600 foot conveyor chain increases another $8/foot. The increased maintenance costs of conventional conveyor chains must also be taken into account. As discussed above, on average 15 minutes/day is spent lubricating and cleaning conventional conveyor chains. Based on a 5 day work week, 52 weeks/year, an average of 65 hours per year is spent on this type of maintenance. At $30/man hour, this is $1,950/year. Since the conveyor chain 300 does not require lubrication or cleaning when used in conjunction with turn wheel assembly 400 , this maintenance cost is not incurred. Over the 42 month life of the conveyor chain 300 , this amounts to a total savings of $6,825. For a typical 600 foot chain, this adds an additional $11.38/foot costs to the use of conventional conveyor chains. Finally, the conveyor chain 300 , because of its superior properties, allows overhead conveyor systems to operate more efficiently, resulting in savings in energy cost of the life of conveyor chain 300 . An average conveyor line utilizing convention conveyor chains draws an average of 12.7 Amps 460 volts, which is equal to 5.8 Kilowatts (kw)/hr. At an average cost of $0.04 per kw/hr and assuming 16 hours of operation/day, the total energy cost is $3.68/day for a conveyor system utilizing conventional conveyor chains. Operating 5 days/week, 52 weeks/year, this amounts to a total energy cost of $956.80/year. The use of the conveyor chain 300 reduces the energy consumption of an overhead conveyor system by 30%, a savings of $287.04/year. Over the 3.5 year (42 month) life of conveyor chain 300 , this amounts to a total savings of $1007.80. For a typical 600 foot chain, the additional energy cost in using conventional conveyor chains adds an addition cost of $1.68/foot. Adding these costs together, the total cost for the use of conventional conveyor chains is $81.06/foot. The cost of using conveyor chain 300 is $59.95/foot. Therefore, the use of conveyor chain 300 results is a savings of $21.11/foot, a 26% cost savings over the life of the conveyor chain 300 . In addition to the cost savings associated with the procurement and maintenance of the conveyor chain 300 , cost savings are also realized when lost production issues are considered. On average, 7 minutes/day production time is lost due to problems with conventional conveyor chains. These problems require the entire conveyor system be shut down, and are generally caused by removing chain slack from the conveyor chain (caused by increases in chain length/pitch), or dealing with problems associated with chain slack. Assuming a 5 day work week, 52 weeks/year, this amounts to 1,820 minutes/year. As a cost of $660 per lost minute of production, this amounts to a cost of $1,202,200/year. As discussed in detail above, the conveyor chain 300 is specially designed to virtually eliminate chain slack when used in the overhead conveyor system of the present disclosure. Therefore, the lost production costs are avoided when conveyor chain 300 is used. Over the 3.5 year life of the conveyor chain 300 , the total savings realized is $4,202,200. Production loss must also be considered when calculating total cost savings. One of the most common causes of lost production is chain stretch. The more a chain stretches, the more links of chain must be removed in order to ensure the overall chain length remains constant. If chain length does not remain constant, then the timing of the conveyor system may be adversely impacted, with adverse impact on the associated industrial process. An average conveyor chain will stretch 2 inches per 10 feet of chain, with 70% of this stretch occurring in the first 5 weeks of use. This chain stretch of 2 inches per 10 feet will result in a loss of capacity equal to one bird for every 30 feet of chain (based on 6 inch centers). For a 600 foot chain, this is a loss of capacity equal to 20 birds per conveyor system complete revolution. A conveyor system with a 600 foot chain processing 91 birds/minute will make a complete revolution every 13.18 minutes. In a 16 hour operating day, a conveyor system makes 72 complete revolutions. At a loss of 20 birds per revolution, a total capacity of 1,440 birds is lost per day. Assuming a 5 day work week, 52 weeks per year, a capacity of 374,400 birds is lost per year. Over the 3.5 year (42 month) life of conveyor chain 300 , a total capacity of 1,310,400 birds is lost. Assuming an average 5 pound bird at $0.50 per pound, each bird lost represents a loss of $2.50. Multiplied by the total number of birds lost, the total cost for the lost capacity over the life of conveyor chain 300 is $3,276,000. The total cost due to production lost due to downtime and production lost due to lost capacity (chain stretch) is $7,478,200 when using conventional overhead conveyor systems. As discussed in detail above, the conveyor chain 300 is specially designed to virtually eliminate chain slack when used in the overhead conveyor system of the present disclosure, thereby eliminating the costs attributable to lost production.	Described are a self-lubricating, overhead conveyor system and the component parts thereof. The self-lubricating overhead conveyor system obviates the need for added lubricants, and comprises three main components: a trolley assembly, a conveyor chain and a turn wheel assembly. In one embodiment, all three components are integrated to provide an improved overhead conveyor system; however, individual components may be used to retrofit conventional overhead conveyor systems. The trolley assemblies contain a self-lubricating precision ball bearing assembly, and are joined together by a surface hardened conveyor chain internally treated to resist corrosion and eliminate flaking. The turn wheel assemblies are configured to engage the conveyor chain and provide continuous lubrication and cleaning to the conveyor chain. All components of the conveyor system of the present disclosure meet criteria established by the United States Department of Agriculture (USDA) for use in food processing applications.	5
FIELD OF THE INVENTION The present invention is related to an oil sleeve bearing, and more particularly to an oil sleeve bearing adapted to be used in a brush-free direct-current fan, which has an oil-storing room to supply oil and is easy to be combined with a shaft of the fan. BACKGROUND OF THE INVENTION In the earlier stage, the bearing used in a motor for holding a shaft is a ball bearing. As known to those skilled in the art, the cost of ball bearings is relatively high. Consequently, an oil sleeve bearing is developed to reduce the cost. Oil sleeve bearings are generally made of copper-based material which has tiny pores inside so that oil can be contained therein and introduced to the shaft owing to a capillary effect to lubricate the shaft. Attributed to low cost, oil sleeve bearings are popularly used in small motors. As interpreted literally, an oil sleeve bearing holds the shaft around, and facilitates the smooth revolving of the shaft by lubrication with oil. If the oil contained in the bearing is inefficient for lubrication, the bearing cannot work any more. Unfortunately, oil is subject to evaporation and leakage so as to adversely effect the lifespans of conventional oil sleeve bearings. In addition, complicated steps are generally required for combining the shafts of the motors with the conventional oil sleeve bearings. One of the examples is shown in FIG. 1 which is a schematic diagram of a conventional brush-free DC fan. The fan shown in FIG. 1 includes a vane portion 1 having a shaft 13 centrally located, an oil sleeve bearing 3 engaged with the shaft 13 for holding it and allowing the shaft 13 to smoothly revolve therein, and a base 5 for stabilizing the entire fan structure. When assembled, the sleeve bearing 3 is mounted into the base 5 from an opening 53 of the base 5, and the shaft 13 enters the base 5 and penetrates through a central hollow portion 31 of the sleeve bearing 3. Subsequently, a fixing ring 6 is engaged with the threaded end portion 14 of the shaft 13 through the opening 53 to secure the entire structure. SUMMARY OF THE INVENTION An object of the present invention is to provide an oil sleeve bearing device, which includes an oil-storing room to supply oil for the bearing wall in contact with the shaft so as to lengthen its lifespan. Another object of the present invention is to provide an oil sleeve bearing device, which is easy to be combined with the shaft by buckling means. The present invention is related to an oil sleeve bearing device for holding a shaft of a motor in a motor base and permitting smooth revolving of the shaft therein. According to a first aspect of the present invention, the oil sleeve bearing device includes a sleeve bearing having a first hollow portion for allowing the shaft to penetrate therethrough, wherein a first lower portion of the sleeve bearing has a first outer diameter, and a first upper portion of the sleeve bearing has a second outer diameter greater than the first outer diameter; and a bearing holder having a second hollow portion for receiving the sleeve bearing and the shaft, and engaged with the motor base so as to hold the shaft in the motor base, wherein a second lower portion of the bearing holder has a first inner diameter greater than the first outer diameter so as to form a space between an outer surface of the sleeve bearing and an inner surface of the bearing holder for storing oil, and a second upper portion of the bearing holder has a second inner diameter approximately equal to the second outer diameter so as to form sealing for the space to prevent oil stored therein from leakage. The bearing holder preferably includes a securing member mounted in the second lower portion thereof, and engaged with a first end portion of the sleeve bearing settled in the bearing holder for holding the sleeve bearing in the bearing holder, and positioning a second end portion of the shaft protruding from the first hollow portion of the sleeve bearing. In an embodiment, the securing member includes a plurality of plastic pieces separately arranged on the inner surface of the bearing holder under the sleeve bearing, so that the second end portion of the shaft is buckled in the oil sleeve bearing device by sliding downwards through the plastic pieces. Alternatively, the securing member includes a flexible ring which is contractible to allow the second end portion of the shaft to pass therethrough, and expandable to allow the second end portion to be positioned in the bearing holder. Preferably, the bearing holder includes a plurality of rib elements separately arranged on the inner surface thereof, located in the second lower portion above the securing member, and having slant surfaces for guiding the sleeve bearing and the shaft to be engaged with the securing member. More preferably, a partition member, e.g. a ring seal, is provided above the sleeve bearing to isolate the sleeve bearing from the external for further preventing oil stored in the bearing holder from leakage. In an embodiment, the ring seal is made of rubber, and has teeth on both an outer surface and an inner surface thereof for buffering oil leakage over the sleeve bearing from the space and the first hollow portion, respectively. The bearing holder can be made of plastic. According to a second aspect of the present invention, the oil sleeve bearing device includes a sleeve bearing having a first hollow portion for allowing the shaft to penetrate therethrough; a bearing holder having a second hollow portion for receiving the sleeve bearing and the shaft, and engaged with the motor base so as to hold the shaft in the motor base; and a securing member mounted in the second hollow portion under the sleeve bearing for holding the sleeve bearing in the bearing holder, and positioning an end portion of the shaft protruding from the first hollow portion; wherein there is a space among the sleeve bearing, the bearing holder, and the securing member for storing oil. The oil sleeve bearing device preferably further includes a ring seal allowing the shaft to pass therethrough, and located above the sleeve bearing in the bearing holder for preventing oil stored in the bearing holder from leakage. The ring seal preferably has teeth on an outer surface thereof for buffering oil leakage over the sleeve bearing from the space. According to a third aspect of the present invention, the shaft has a bullet-shaped head portion, and a recessed neck portion, and the oil sleeve bearing device includes a sleeve bearing having a first hollow portion for allowing the shaft to penetrate therethrough; a bearing holder having a second hollow portion for receiving the sleeve bearing and the shaft; and a plurality of elastic pieces located under the sleeve bearing and separately attached onto an inner surface of the bearing holder, so that the bullet-shaped head portion of the shaft is allowed to easily slide downwards through the elastic pieces so as to be buckled owing to the engagement of the recessed neck portion with the elastic pieces. In a preferred embodiment, the bearing holder includes a plurality of rib elements separately arranged on the inner surface thereof, located above the elastic pieces, and having slant surfaces for guiding the shaft to pass through the elastic pieces. According to a fourth aspect of the present invention, the shaft has a bullet-shaped head portion, and a recessed neck portion, and the oil sleeve bearing device includes a sleeve bearing having a first hollow portion for allowing the shaft to penetrate therethrough; a bearing holder having a second hollow portion for receiving the sleeve bearing and the shaft; and a flexible ring attached to an inner surface of the bearing holder, contractible to allow the bullet-shaped head portion of the shaft to pass therethrough, and expandable to fit the neck portion of the shaft so as to position the shaft in the bearing holder. BRIEF DESCRIPTION OF THE DRAWING The present invention may best be understood through the following description with reference to the accompanying drawings, in which: FIG. 1 is a schematic cross-sectional view of a conventional brush-free DC fan; FIG. 2 is a disassembled cross-sectional view schematically showing diagram showing a preferred embodiment of an oil sleeve bearing device according to the present invention; FIG. 3 is a schematic cross-sectional view showing an assembly of the oil sleeve bearing device of FIG. 2; and FIG. 4 is a schematic cross-sectional view showing another embodiment of the bearing holder according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for purpose of illustration and description only; it is not intended to be exhaustive or to be limited to the precise form disclosed. Please refer to FIGS. 2 and 3 which are schematic disassembled and assembled cross-sectional views of a preferred embodiment of an oil sleeve bearing device according to the present invention with a vane structure and a motor base of a DC fan. The oil sleeve bearing device includes a cylindrical bearing holder 92, a sleeve bearing 93, and a ring seal 94. When assembled, the bearing holder 92 is incorporated into the motor base 95, the sleeve bearing 93 is placed into the bearing holder 92, the ring seal 94 is also placed into the bearing holder 92 and located above the sleeve bearing 93, and then the shaft 16 of the vane portion 91 penetrates through the ring seal 93 and the sleeve bearing 93 and enters the bearing holder 92 to be positioned in the bearing holder 92. The structures of the above mentioned parts are respectively described as follows with reference to FIG. 2. Vane Portion and Shaft The shaft 16 extends from the vane portion 91, and has a bullet-shaped head 15 and a recessed neck 17. In the vane portion 91 near the shaft 16, a plurality of small trenches 11 are created. Ring Seal The ring seal 94 is made of rubber, and has a hollow cylindrical portion 43. The inner surface and the outer surface of the ring seal 94 both have a plurality of teeth 42 and 41, respectively. Sleeve Bearing The sleeve bearing 93 is made of copper-based material which has tiny pores inside, and can be formed by a powder sintering technique. The sleeve bearing 93 has a hollow cylindrical portion 31, and is divided into an upper portion 32, a lower portion 33, and an end portion 34. The outer diameter of the upper portion 32 is greater than that of the lower portion 33, and even greater than that of the end portion 34. Bearing Holder The bearing holder 92, preferably made of plastic, has a hollow cylindrical portion 25, and are divided into three portions, an upper portion 28, a lower portion 27 and an end portion 26. The upper portion 28 has an inner diameter approximately equal to the outer diameter of the upper portion 32 of the sleeve bearing 93. The lower portion 27 has an inner diameter greater than the outer diameter of the lower portion 33 of the sleeve bearing 93. In the end portion 26, a securing member 24 including a plurality of elastic pieces 21 is mounted on the inner surface of the bearing holder 92, and after installed therein the securing member 24, the residual inner diameter of a part of the end portion above the elastic pieces 21 is approximately equal to the outer diameter of the end portion 34 of the sleeve bearing 93. As for the smallest space 29 remained among the elastic pieces 21 should be slightly smaller than the size of the bullet-shaped head 15 of the shaft 16, and approximately equal to the size of the neck 17 of the shaft 16. In addition, a plurality of rib elements 22 having slant surfaces 221 are separately attached onto the inner surface of the bearing holder 92 in the lower portion 27. Base The base 95 has a hollow cylindrical portion 52 approximately equal to the outer diameter of the bearing holder 92, and it has a sealed bottom 53. The assembling details are now illustrated with reference to FIGS. 2 and 3. When the bearing holder 92 is incorporated into the base 95, the bearing holder 92 is placed into the hollow portion 52 of the base 95, and the approximate equality of the diameters of the bearing holder 92 and the hollow portion 52 ensures the stability of the bearing holder 92 in the base 95. When the sleeve bearing 93 is combined with the bearing holder 92, the sleeve bearing 93 is placed into the hollow portion 25 of the bearing holder 92, and positioned under the guidance of the rib elements 22. The end portion 34 of the sleeve bearing 93 slides downwards along the slant surfaces 221 of the rib elements 22, and is stopped by the securing member 24. The end portion 34 is closely engaged into the end portion 26 of the bearing holder 92 owing to the approximate equality of diameters. The upper portion 32 of the sleeve bearing 93 is in extremely close contact with the upper portion 28 of the bearing holder 92 owing to the approximate equality of diameters. The outer diameter of the lower portion 33 of the sleeve bearing 93 is less than the inner diameter of the lower portion 27 of the bearing holder 92 so that there is a space 6 existent between the sleeve bearing 93 and the bearing holder 92. The space 6 can be used to store oil which is supplied to the sleeve bearing 93 for maintaining durable lubrication for the revolution of the shaft 16. In addition, the space between every two rib elements which are separately arranged can also store oil therein. Subsequently, the ring seal 94, preferably made of rubber, is placed into the bearing holder 92, and located immediately above the sleeve bearing 93. It can be seen from FIG. 3 that there is small vacant space 43 existent between the teeth 41 and the inner surface of the bearing holder 92. If oil leaks out from the room 6 and oozes out of the sleeve bearing 93, the vacant space 43 can buffer the oil leakage out of the oil sleeve bearing device. Afterwards, the shaft 16 of the vane portion 91 penetrates through the hollow portions 43 and 31 of the ring seal 94 and the sleeve bearing 93, and enters the hollow portion 25 of the bearing holder 92. The shaft 16 slides downwards, and the bullet-shaped head 15 slightly pushes away the elastic pieces 21 so as to pass through the space 29. The neck 17 of the shaft 16 is then fitted with the elastic pieces 21 and positioned in the space 29. By the way, there is also small vacant space 44 existent between the teeth 42 and the outer surface of the shaft 16 so as to buffer oil leakage from the hollow portion 25 of the bearing holder 92. Although the close contact between the upper portions 32 and 28 of the sleeve bearing 93 and bearing holder 92 and the arrangement of the ring seal 94 have provided excellent oil seal for the present oil sleeve bearing device, additional design in the vane portion 91 around the shaft 16 for further oil leakage prevention is suggested here. Trenches 11 as shown in FIG. 3 are provided so that leaking oil can be buffered by the alternately arranged trenches 11 and posts 12. It is understood that the numbers of the elastic pieces and the rib elements can be selected as required. Alternatively, the elastic pieces can be substituted by a flexible ring 23 which can contract owing to the squeezing of the bullet-shaped head 15 of the shaft 16, and then recover to original size to fit the neck 17 of the shaft 16, as shown in FIG. 4. After the oil sleeve bearing device is assembled and combined with the vane portion, an oil-rinsing procedure under vacuum is performed to make oil introduced into the tiny pores of the sleeve bearing for lubrication and the room among the sleeve bearing, the bearing holder and the securing member for storing. While the invention has been described in terms of what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention need not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.	An oil sleeve bearing device for holding a shaft of a motor in a motor base and permitting smooth revolving of the shaft therein is disclosed. The oil sleeve bearing device includes a sleeve bearing for holding the shaft, a bearing holder for supporting the sleeve bearing, and a securing member for positioning the sleeve bearing and the shaft in the bearing holder, and there exists a room among the sleeve bearing, the bearing holder, and the securing member for storing oil which can be supplied to the sleeve bearing for lubrication. A buckle structure of the securing member is also disclosed so as to allow the sleeve bearing and the shaft to be easily secured to the bearing holder.	5
TECHNICAL FIELD The present invention relates to a catalyst, which is suitable for use in the process where oxygenates, i.e. chemical compounds containing oxygen as part of their structure (e.g. alcohols or ethers) are converted to olefins. A method for the formation of the catalyst is also provided. More specifically the invention concerns a catalyst for the conversion of oxygenates to olefins, said catalyst being based on SUZ-4 zeolite. The SUZ-4 zeolite is modified in a number of ways with the purpose to yield a catalyst with improved properties for the conversion of oxygenates to olefins. BACKGROUND TO THE INVENTION SUZ-4 zeolite has been given the three-letter IUPAC designation code SZR. The framework of the SUZ-4 zeolite consists of 4-, 5-, 6-, 8- and 10-membered rings of 3-dimensional channel systems. It has an ortho-rhombic unit cell with dimensions of a=18.8696, b=14.4008 and c=7.5140 Å, respectively. The 10-membered ring channels of the SUZ-4 zeolite are the main straight channels in the framework, and they are interconnected by zig-zag 8-ring channels. The 10-ring straight channels of the SUZ-4 zeolite have dimensions of 4.6×5.2 Å, i.e. notably smaller than the 10-ring channels found in the ZSM-5 zeolite (5.3×5.5 and 5.4>5.6 Å). Within the catalyst area, the SUZ-4 zeolite is known to be a selective and stable dehydration catalyst in the process for producing dimethyl ether from methanol (Jiang, S. et al., Chemistry Letters 33, no. 8, 1048 (2004)). According to U.S. Pat. No. 6,936,562 B2 (General Motors Corp.), certain metal-exchanged SUZ-4 zeolites have been prepared which have catalytic activity in the reduction of NO x in the exhaust gas from a hydrocarbon or alcohol fuelled engine. Similar hydrothermally-stable catalysts based on substituted SUZ-4 zeolites are described in the related U.S. Pat. No. 6,645,448 B2 (General Motors Corp.), and in U.S. Pat. No. 5,118,483 B2 (British Petroleum Co.) various crystalline forms of the SUZ-4 zeolite based on crystalline (metallo) silicates are described. It should be noted that—with reference to e.g. U.S. Pat. No. 5,118,483—the standard methods for forming SUZ-4 zeolites will usually provide thermochemically-preferred Si/Al stoichiometries, regardless of the molar ratios of the Si and Al components in the starting materials. EP 0 706 984 A1 (BP Chemicals Ltd.) discloses the catalytic use of SUZ-4 zeolite for the isomerisation of hydrocarbons, and in U.S. Pat. No. 6,514,470 B2 (University of California) a large number of aluminium-silicate materials, including SUZ-4 zeolite, are used as catalysts for lean burn exhaust abatement. JP 2009-233620 A (Tosoh Corp.) describes the use of SUZ-4 zeolite in an SCR catalyst with the objective to give the catalyst improved hydrothermal durability. Most recently, variants of the methanol to olefins (MTO) process have been disclosed in EP 1 963 241 A2 and in WO 2008/042616 A2 (both to UOP LLC). One of the main challenges within the field of MTO catalysis is that the known catalysts have a very limited life span, requiring continuous regeneration at elevated temperature which eventually lead to irreversible damage to the catalyst. According to the inventors, this is also the case with the SUZ-4 zeolite-based catalysts, because the life span of the current SUZ-4 zeolite-based catalyst prepared using the standard methods in the MTO catalysis field does not exceed that of other catalysts such as silicoaluminophosphate molecular sieves (e.g. SAPO-34). However, it has now surprisingly been found that the life span of the SUZ-4 zeolite-based catalyst for MTO use can be markedly improved by either modification of the zeolite acidity (i.e. by increasing the Si/Al ratio, partial ion-exchange of alkali counter-ions) SUMMARY OF THE INVENTION The invention concerns a catalyst for the conversion of oxygenates to olefins, said catalyst consisting essentially of a selected SUZ-4 zeolite. The catalyst according to the invention is characterised in that the zeolite has a Si/Al ratio of at least 20, preferably between 20 and 500. The most preferred Si/Al ratio in the zeolite is between 20 and 100. Furthermore, the invention concerns a process for the preparation of the catalyst, said method comprising the steps of: (a) providing a conventional/standard SUZ-4 zeolite having a Si/Al ratio of less than 20, and (b) increasing the Si/Al ratio to 20 or above by contacting the product of step (a) with water vapour at elevated temperatures. In the above process, step (b) is preferably performed at a temperature of 400-700° C. Furthermore it is preferred to perform step (b) for 1-12 hours by feeding 1-20 g H 2 O per g of catalyst per hour. The SUZ-4 catalyst resulting from step (b) of the process is preferably washed with an aqueous acid solution. The catalyst according to the invention is used for the conversion of oxygenates to olefins. The oxygenates to be converted to olefins are preferably selected from the group consisting of C1 to C4 alcohols. The most preferred oxygenate to be converted to an olefin is methanol. BRIEF DESCRIPTION OF THE FIGURES FIG. 1 shows the XRD diffraction profile of SUZ-4 having gel Si/Al=8 and 13. FIG. 2 shows an SEM image of SUZ-4 having Si/Al=8 in the synthesis gel. FIG. 3 shows a TEM image of an SUZ-4 zeolite-based catalyst having Si/Al=8 in the synthesis gel. FIG. 4 shows the BET isotherm of SUZ-4 having gel Si/Al=8 in the synthesis gel. FIG. 5 shows GC-MS chromatograms of SAPO-34, SUZ-4, and ZSM-5 catalysts tested under identical reaction conditions after 5 minutes on stream. NB: C1 is not included in the chromatogram. (400° C. and WHSV=2.05 gg −1 h −1 ) DETAILED DESCRIPTION OF THE INVENTION According to the invention the selected SUZ-4 zeolite has a Si/Al ratio of at least 20, preferably between 20 and 500 as determined using SEM-EDX, ICP and ammonia TPD. A more preferred Si/Al ratio is between 20 and 100. The SUZ-4 zeolite-based catalyst is synthesized in a manner known per se by preparing (i) a solution of Al-wire in aqueous MOH, where M is an alkali metal, (ii) a 25 wt % solution of tetraethylammonium hydroxide (TEAOH) and (iii) a 40 wt % solution of Ludox-AS 40, mixing the solutions (i)-(iii) at 60° C. and crystallizing the resultant gel at 160° C. with stirring, followed by (iv) ion-exchange to remove the M ions completely from the material and (v) calcination to obtain the zeolite in hydrogen form. According to the invention, this standard method gives a H-SUZ-4 catalyst with high density of acid sites, and it deactivates very rapidly during oxygenate (methanol) conversion to olefins. It should be noted that the conversion of methanol to olefins is novel in this work, the drawback is the rapid deactivation. Thus, the Si/Al ratio is then adjusted to the desired value by changing the amount of Al-wire dissolved in the aqueous MOH solution (i). The Si/Al ratio can also be adjusted to the desired value another way, i.e. by contacting the product with water vapour at elevated temperatures (so-called “steaming”). The steaming is preferably performed for a period of 1-12 hours by feeding 1-20 g H 2 O per g of catalyst per hour at a temperature of 400-700° C. After the steaming the resulting SUZ-4 catalyst is washed with an aqueous acid solution. While it is known from the above citations that SUZ-4 zeolites may be used as catalysts in various contexts, the specific use of SUZ-4 zeolite materials as catalysts in the conversion of oxygenates to olefins is novel. Thus, the present invention is related to the use of the above-mentioned SUZ-4 zeolite material in the conversion of oxygenates, especially methanol/dimethyl ether (DME), to olefins. Due to the unique topology (SZR topology), consisting of a 3-dimensional channel system of straight 10-rings and zig-zag 8-rings, a surprisingly high selectivity (60-70%) to light olefins (ethylene and propylene) is observed. As a by-product (approximately 10-20%), olefins with a hydrocarbon chain length in the gasoline range are obtained. The selectivity to aromatic hydrocarbons is typically below 2%. As a consequence of the selectivities observed, the catalyst has a high potential to be used as a catalyst for the production of light olefins (ethylene and propylene) with a gasoline fraction having a low content of aromatic compounds as a co-product. Methane, which is also regarded as co-product during olefin production, could be used as a source for the necessary external thermal energy for the MTO process. The present invention will now be illustrated further in the following examples. EXAMPLE 1 (A) Synthesis of SUZ-4 Zeolite Using the Standard Method An SUZ-4 zeolite was synthesized according to the procedure published by S. Jiang et al., Chemistry Letters 33, no. 8, 1048 (2004). The following solutions were prepared: (a) 0.4 g Al-wire dissolved in a KOH solution (3.3 g KOH in 50.6 g H 2 O) (b) 7.93 g TEAOH (25 wt %) (c) 18.23 g LUDOX AS-40 (40 wt %). To the clear solution (a), solution (b) and solution (c) were added successively while stirring at 60° C. The batch composition of the synthesis mixture was 7.92 K 2 O:Al 2 O 3 :16.21 SiO 2 :1.83 TEAOH:507 H 2 O. The gel was transferred to 40 ml Teflon lined stainless steel autoclaves. The Si/Al ratio was varied by changing the amount of Al-wire dissolved in KOH solution. Crystallization of the gel was carried out under horizontal stirring conditions using a Teflon coated bar magnet at 160° C. for 2 to 5 days. When the crystallization was complete, the reaction mixture was washed with distilled water, and the product was recovered by filtration. The calcined material as prepared was subjected to ion-exchange three times with an aqueous 1N NH 4 NO 3 solution under reflux, washed with deionized water, dried at 120° C. for 3 hours and then calcined at 550° C. for 12 hours. The synthesis conditions used are summarized in table 1 below. TABLE 1 Synthesis conditions used in the crystallization of SUZ-4 zeolite Synth. Si/Al Cryst. Cryst. No. gel time conditions* Result* SUZ4-1 8 2 days H.S. SUZ-4a SUZ4-2 8 5 days H.S. SUZ-4 SUZ4-3 13 3 days H.S. SUZ-4 SUZ4-4 17 2 days H.S. Amorph. *In the above table, H.S. means horizontal stirring, and SUZ-4a means SUZ-4 + amorphous. (B) Characterization and Catalyst Tests X-Ray Diffraction The purity and crystallinity of the products were identified using X-ray diffraction on a Siemens D-5000 diffractometer with Bragg-Brentano geometry, position sensitive detector and CuKα1 radiation (λ=1.5406 Å). X-ray diffraction (XRD) data were analyzed using EVA 8.0, developed by SOCABIM. The diffraction pattern was compared with the data in the powder diffraction file (PDF) database compiled and revised by Joint Committee on Powder Diffraction Standards International Centre. Surface Area The BET surface area of the SUZ-4 catalysts was determined by nitrogen adsorption at a temperature of 77 K using a BELSORP-mini II instrument. Prior to the measurement the catalyst was pretreated for 5 hours (out-gassing for 1 hour at 80° C. and for 4 hours at 300° C.). Scanning and Transmission Electron Microscopy SUZ-4 crystals were sprinkled on a carbon tape mounted on a copper grid. The crystal size and shape were investigated using Scanning Electron Microscopy, Quanta 200 F (FEI). Similarly TEM images were taken and electron diffraction revealed unit cell parameters and orientation of the 8- and 10-ring channels within the crystal. The template was removed by calcination under static air at 550° C. for 6 hours. The calcined samples were ion-exchanged for 3×2 hours with 1M NH 4 NO 3 in a 70° C. water bath. The ion-exchanged catalysts were calcined at 550° C. for 2 hours in static air, for 1 hour ex situ in a flow of pure oxygen, and for 1 hour in situ in the fixed bed reactor in a flow of pure oxygen prior to each catalytic experiment to desorb ammonia. The calcined SUZ-4 catalysts were tested for the MTH reaction using a fixed bed reactor. 50 mg of catalysts and temperatures between 350 and 450° C. were used. The catalysts were pressed, gently crushed and sieved to a particle size of 0.25-0.42 mm. Before each test, the catalysts were calcined in situ at 550° C. (see above) under a flow of oxygen for 1 hour. Helium was used as a carrier gas and methanol was fed using a bubble saturator placed in a water bath at 20° C. A methanol feed rate (expressed as WHSV, i.e. weight hourly space velocity, which is defined as the weight of feed flowing per unit weight of the catalyst per hour) of 2.05 gg −1 h −1 was used. The reaction products were analyzed by GC and GC-MS. The GC analyses were performed using an on-line gas chromatograph (Agilent 6890 A with FID) using a Supelco SPB-5 capillary column (60 m, 0.530 mm i.d., stationary phase thickness 3 μm). The temperature was programmed between 45 and 260° C. with a heating rate of 25° C. min −1 (hold time 5 min at 45° C. and 16 min at the final temperature). GC-MS analyses were performed using a HP 6890 gas chromatograph equipped with a GS-GASPRO column (60 m, 0.32 mm) and a HP-5973 Mass Selective Detector. Each analysis took 40 minutes, and the temperature was programmed between 100 and 250° C. with a heating rate of 10° C. min −1 (hold time 10 min at 100° C. and 15 min at 250° C.) (C) Results FIG. 1 displays the XRD profiles of SUZ-4 having Si/Al ratios of 8 and 13 in the synthesis gel. By comparing the observed diffraction profile with a theoretically calculated diffraction profile ( FIG. 1 bottom), it was observed that the product was free from structural impurities. FIG. 2 and FIG. 3 respectively displays the SEM and TEM image of an SUZ-4 zeolite-based catalyst having Si/Al=8 in the synthesis gel. The crystals were needle-shaped and ˜2-3 μm in length. FIG. 3 displays (a) TEM overview micrograph. (b) Micrograph and diffraction image (insert) of random crystallite. FIG. 4 displays the BET isotherm for the SUZ-4 catalyst having Si/Al=8. The isotherm is typical for a microporous material. The surface area of the catalyst was found to be 346 m 2 /g. FIG. 5 displays GC-MS chromatograms of the methanol to hydrocarbon reaction over different zeolites, reaction carried out under identical conditions. EXAMPLE 2 Determination of Methanol Conversion Table 2 below shows the percentage methanol conversion and the product selectivities at different reaction temperatures; WHSV=2.05 gg −1 h −1 was used. At 350° C. the initial conversion of the catalyst was 83%, and the catalyst showed a very high selectivity for C1 (21%, second most abundant species). Increasing the temperature to 400 and 450° C. improved the initial conversion by the catalyst to ˜100%, the selectivity for C1 was decreased by approximately a factor of 2. At these reaction temperatures, C2 and C3 were the most abundant species (C2+C3>60%). TABLE 2 Methanol conversion, product selectivity and C4 hydrogen transfer index of SUZ-4 catalyst for the MTH reaction at different reaction temperatures after 3 minutes on stream, Si/Al = 8. (WHSV = 2.05 gg −1 h −1 ) Temp. Conversion C1 C2 C3 C4alkene 350° C. 83.0% 21.34 13.56 37.48 13.04 400° C. 99.7% 10.24 24.35 37.71 14.11 450° C. 99.7% 11.92 35.79 30.74 12.48 Temp. C4alkane C5 C6+ C4HTI 350° C. 1.85 7.04 5.68 0.12 400° C. 2.60 7.78 3.20 0.16 450° C. 1.36 5.19 2.53 0.10 It is firmly believed that the high selectivity towards C2 and C3 is caused by the needle-like morphology of the catalyst crystals, as seen by SEM. A simulation of crystal growth indicates that the 10-ring channels run in the direction of the needles. If these needles are described as cylinders, the simulation result means that only the two bases of each cylinder serve as exits through 10-ring channels. The major part of the external crystal surface will serve as exits through 8-rings, which are orthogonal to the 10-rings. This gives rise to a product shape selectivity dominated by 8-rings, leading to high selectivities towards C2 and C3. The SUZ-4 sample tested deactivates very fast. After 43 minutes (the effluent is sampled every 40 minutes), the conversion was negligible. This is consistent with the relatively high selectivity towards C1 (and also propane), which is inherently linked to formation of aromatics and coke. This rapid deactivation may well be attributed to the very high Al content in the sample, which means that the density of acid sites is untypically high for methanol conversion catalysts. EXAMPLE 3 Comparison of SUZ-4 to ZSM-5 and SAPO-34 For the sake of comparison, ZSM-5 and SAPO-34 were tested for the MTH reaction under identical reaction conditions as those of SUZ-4, and the results are presented in FIG. 5 and Table 3. Note that SAPO-34 is currently used as a commercial MTO catalyst. Table 3 displays the product selectivities for the three different zeolites at 400° C. The GC analyses were performed after 3 minutes on stream, and the catalysts displayed approximately 100% conversion. ZSM-5 catalyst has high selectivity for heavier hydrocarbons than SUZ-4 and SAPO-34 catalysts (see FIG. 5 and Table 3). TABLE 3 Product selectivity of the MTH reaction over ZSM-5, SAPO-34, and SUZ-4 catalysts, WHSV = 2, 400° C., and full conversion of methanol Catalyst C1 C2 C3 C4alkene ZSM-5 0.28 7.58 21.20 8.77 SUZ-4 10.24 24.35 37.71 14.11 SAPO-34 0.56 29.65 42.59 16.70 Catalyst C4alkane C5 C6+ C4HTI ZSM-5 18.15 13.19 30.83 0.67 SUZ-4 2.60 7.78 3.20 0.16 SAPO-34 1.15 7.43 1.91 0.06 The C4 alkane selectivity of the ZSM-5 catalyst is notably higher than both that of the inventive SUZ-4 catalyst and that of the SAPO-34 catalyst, giving rise to a higher C4 hydrogen transfer index. Except for the selectivity for methane (C1), the SAPO-34 and SUZ-4 catalysts showed comparable product selectivities for all the other hydrocarbons. For both materials C2 and C3 were the most abundant species (SAPO-34 C2+C3=72.3 and SUZ-4 C2+C3=61.1). The inventive SUZ-4 catalyst showed a much higher selectivity for methane (approximately 10%) than SAPO-34 (>1%).	A catalyst for the conversion of oxygenates, such as alcohols or ethers, to olefins consists essentially of a selected SUZ-4 zeolite that has a Si/Al ratio of at least 20, preferably between 20 and 500, especially between 20 and 100. The basic SUZ-4 zeolite is prepared in a manner known per se, whereafter the Si/Al ratio is increased to the desired value. The selected SUZ-4 zeolite catalyst of the invention has a longer life time and a better product selectivity than the conventional/standard SUZ-4 zeolite catalysts.	1
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] Not applicable. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] Not Applicable. BACKGROUND OF THE INVENTION [0003] (1) Field of the Invention [0004] The present invention relates to a method and apparatus for identifying a work object and, more particularly, to a method and apparatus which are operable to permit similar work objects readily to be distinguished from one another. [0005] (2) Description of the Prior Art [0006] A wide variety of environments exist in which items may be misplaced due to a mutiplicity of similar, or identical, items which have been placed in the general vicinity. Simply stated, the items are substantially indistinguishable from each other and/or are in such proximity to each other that identification of a given item from among the many is very difficult, if not impossible. [0007] Some of the environments in which this experience may be present include, for example, any event at which there are a multiplicity of similar items and the nature of the event is such that the items involved are frequently, though, temporarily, set down. They may be set down for many reasons. For example, at athletic events, concerts, other social events, schools and other situations in which a considerable number of people congregate, the misplacement of bottles, cups, glasses and the like is a frequent occurrence. The items effectively become intermixed so as to be lost in the conglomeration. [0008] This fact may lead to other consequences. The very fact that a person cannot be, or may not be, certain of the owner of the item, may create an uncomfortable lack of confidence. The item may effectively be contaminated in some respect. There may be a reticence because of the risk of the communication of unsanitary or otherwise unhealthful conditions. Real, or imagined, risk of such exposure is frequently enough for individuals not to assume the risk. The discomfort of knowing that you might drink from someone else's container frequently causes people not to take that chance, but rather to get a new drink in a new container. This, of course, causes waste, unnecessary expense, the proliferation of unfinished drinks, the spilling of abandoned drinks, and, more broadly, waste of natural resources. [0009] There are many other environments in which such risks may be greater. For example, healthcare facilities such as hospitals, doctor's offices, nursing homes and the like may exacerbate these conditions. Knowledge that there actually are unhealthful conditions present intensifies these concerns among patients, nurses, doctors and other healthcare workers. Greater certainty as to the physical conditions to which they are exposed, or might be exposed, would be comforting as well as a useful tool in avoiding the spread of disease and the like as a result of mistake. [0010] As a hedge against the intermixing of containers, it has been known for people to place their names on their containers using labels, or by marking directly on the container. However, in both such circumstances, it is common for condensation, contact, or other conditions to cause these identifiers to smear or otherwise come off. In other cases, containers of different, colors, shapes, sizes, or the like may be selected as a means for more certain identification. Of course, there are not enough distinguishing features available for this to serve the desired purpose. [0011] Therefore, it has long been known that it would be of considerable advantage to have a method and apparatus which could be employed dependably to distinguish from among a plurality of substantially identical items; which could immediately afford the means for certain identification; which could operate with a dependability not heretofore achievable; which could rapidly be operated and without the disclosure to others of which may be, or be perceived to be, confidential information; which had application to a host of different types of work objects and environments; which reduced substantially the possibility of the communication of diseases, unhealthy conditions, or the like; and which would otherwise be entirely successful in achieving its operational objectives. BRIEF SUMMARY OF THE INVENTION [0012] Therefore, it is an object of the present invention to provide an improved method and apparatus for identifying a work object. [0013] Another object is to provide such a method and apparatus which can be employed in a wide variety of operative environments to permit work objects to be distinguishable one from another. [0014] Another object is to provide such a method and apparatus which can be employed to achieve absolute certainty in identifying a specific work object. [0015] Another object is to provide such a method and apparatus which have particular utility when used on containers for substances which may be consumed. [0016] Another object is to provide such a method and apparatus which can be employed with a precision not heretofore achieved in the art. [0017] Another object is to provide such a method and apparatus which can be used by people regardless of their visual acuity in identifying a specific work object rapidly and dependably. [0018] Another object is to provide such a method and apparatus which can be employed without the dependence upon having access to any other items such as tools, markers, or the like. [0019] Another object is to provide such a method and apparatus which have particular utility in large social gatherings, schools, hospitals, other healthcare facilities and the like. [0020] Another object is to provide such a method and apparatus which have particular utility in providing a means for avoiding the spread of communicable diseases or otherwise unhealthful conditions, help to avoid waste, are of minimal cost and simplicity of use to a degree not heretofore available in the prior art. [0021] Further objects and advantages are to provide improved elements and arrangements thereof in an apparatus for the purpose described which is dependable, economical, durable and fully effective in accomplishing its intended purposes. [0022] These and other objects and advantages are achieved, in the preferred embodiment of the present invention, in a method and apparatus for identifying a work object from among a plurality of work objects, the apparatus including a plurality of identifiers mounted on the work object in a position to be visible; a plurality of different symbols individually borne by the identifiers; and a method for selecting one or more symbols borne by the identifiers to distinguish the work object from the plurality of work objects. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS [0023] FIG. 1 is a perspective view of a work object, in this case a disposable water bottle, employing the method and having apparatus of the present invention. [0024] FIG. 2 is a side elevation of the bottle of FIG. 1 . [0025] FIG. 3 is a transverse vertical section of the bottle of FIG. 1 taken on line 3 - 3 in FIG. 2 . [0026] FIG. 4 is a fragmentary side elevation of the bottle of FIG. 1 showing the method and apparatus of the present invention thereon. [0027] FIG. 5 is a perspective view of a second embodiment of the method and apparatus of the present invention. [0028] FIG. 6 is an enlarged fragmentary transverse horizontal section of the bottle of FIG. 1 showing several portions of the method and apparatus of the present invention employed in the practice thereof. DETAILED DESCRIPTION OF THE INVENTION [0029] Referring more particularly to the drawings, the apparatus of the present invention is generally indicated by the numeral 10 in FIG. 1 . As shown in FIG. 1 and the subsequent views, the apparatus is borne by, and the method is practiced with respect to, a work object 20 which, in this case and for illustrative convenience, is a plastic water bottle. It will be understood that virtually any type of work objects can be the subject of the method and apparatus of the present invention, whether they hold liquid for drinking or another type of consumable, or are used for entirely different purposes. [0030] The work object or water bottle 20 has a bottom wall 21 and a top wall 22 at the opposite end thereof. The water bottle has a side wall 23 , which interconnects the bottom wall and top wall, and a cap or lid assembly 24 . The water bottle has an interior 25 containing a consumable. In this case, of course, the consumable is drinking water. For purposes of illustrative convenience, the water bottle can be viewed as having an identifier zone 26 which is preferably, although not necessarily, on the side wall 23 on the upper portion of the water bottle adjacent to the top wall 22 and extending entirely about the water bottle. [0031] A plurality of indicators, identifiers, or protrusions 35 are mounted in spaced relation to each other on the water bottle in the identifier zone 26 of the side wall 23 . In the illustrative embodiment hereof, the protrusions are arranged in ten vertical rows 36 and three horizontal rows 37 , as best shown in FIG. 2 . Each of the protrusions has an outer convex surface 38 and an inner concave surface 39 . The operation of the method and apparatus of the present invention encompasses depression of selected protrusions which converts each such protrusion so that it inverts inwardly to protrude toward the interior 25 of the water bottle. Each such protrusion is thus caused to have an outer inverted concave surface 40 and an inner inverted convex surface 41 . It will be understood that the thickness and composition of the plastic material from which the water bottle is made is such that a certain amount of flexing of the side wall 23 takes place upon the application of pressure thereto. The opposite convex and concave surfaces 38 and 39 respectively of the protrusions 35 are hemispheres. Each protrusion can be flexed upon the application of individual pressure thereto such as with the thumb of the person using it. Such flexing causes the convex surface to flex inwardly to form a concave surface facing outwardly. This occurs without bending, or denting the sidewall. [0032] A symbol 42 is printed, or otherwise formed, on the outer surface of each protrusion, as best shown in FIG. 1 . In the illustrative example hereof, the symbols are identified by numerals 42 . As shown in FIG. 1 , in the illustrative example, the protrusions form a vertical row having the same numeral thereon while each of the three horizontal rows has numerals in sequence from “0” to “9”. It will be understood that other symbols can alternatively be employed, such as alphabetical letters, geometric symbols, other types of symbols, or the like. [0033] It will be seen in FIGS. 2 , 3 and 5 that none of the protrusions have yet been depressed to cause them to invert. Conversely, in FIGS. 1 and 6 protrusions “ 6 ”, “ 7 ”, “ 8 ” and “ 9 ” in a single horizontal row 37 have been depressed to cause them to invert thereby creating an identifying code. The illustrative identifying code is thus “6789” which could, for example, correspond to a person's street address. Alternatively, the inverted protrusions can be selected in ten different vertical rows, or any other combination thereof. [0034] FIG. 5 shows a second embodiment of the method and apparatus of the present invention. FIG. 5 shows an attachment plate 50 of the second embodiment. The attachment plate can be constructed of any suitable material, such as a plastic and has a front surface 51 and an opposite back surface 52 . The back surface preferably bears an adhesive which permits it to be adhesively attached to any type of work object, such as a water bottle. Since the attachment plate is plastic, it has flexibility allowing it to be adhesively attached to a work object of any size. The front surface 51 mounts the protrusions 35 which are used in the same manner and for the same purpose as the protrusions of the first embodiment of the subject invention heretofore set forth. OPERATION [0035] The operation of the described embodiment of the subject invention is believed to be clearly apparent and is briefly summarized at this point. [0036] Operation of the method and apparatus of the subject invention can, perhaps, best be illustrated using a representative environment of usage. For this purpose, it will be understood that the environment of use is a social event at which there are many people drinking consumables from bottles, cups and the like. In this illustrative example, the bottles, cups and the like are all equipped so as to be operable in accordance with the method and apparatus of the present invention. [0037] In this environment, each person with such a bottle, cup, or the like can press inwardly of the side wall 23 selected protrusions 35 so as, in effect, to create a code to identify that bottle, cup, or the like. Pressure toward the interior 25 , by for example using the thumb, causes the selected protrusion to invert, or in other words to become recessed, or concave. This concave configuration, in effect, appears to circle the number selected. Once a code is so formulated, it has the general appearance shown in FIGS. 1 and 6 . The specific code selected could, or course, be any combination of numbers such as, for example, the telephone number or street address of the person whose bottle, cup or other vessel is being used. Alternatively, as another example, the specific code could be entirely randomly selected. [0038] In any case, all of the work objects so designated are rapidly distinguishable from each other with absolute certainty. Accordingly, all of the problems experienced in conventional situations are avoided. Furthermore, in view of there being three rows of ten choices each, the number of choices is so large as to make it virtually impossible that two or more people could by chance choose to select the same code. [0039] In addition, since the protrusions in both their respective convex and concave forms extend out of the plane defined by the side wall 23 , there is a distinguishable tactile sensation by running one's fingers over them. Accordingly, a person with limited or otherwise compromised eyesight, knowing the arrangement of the protrusions and the numerals thereon, can use the method and apparatus of the present invention for its intended purpose relying entirely on the sense of touch. [0040] Therefore, the method and apparatus of the present invention can be employed to distinguish an item from a plurality of substantially identical items; can immediately provide certain identification of the item; is entirely dependable in use and not subject to failure; can be used in such a way as to maintain confidentiality if desired; has application to a multiplicity of different environments of use; can be employed so as to avoid the possibility of the communicable diseases; and is otherwise entirely successful in achieving its operational objectives. [0041] Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention which is not to be limited to the illustrative details disclosed.	A method for identifying a work object from among a plurality of work objects, the method including the steps of applying indicators to the work object which are individually selectable; and activating the indicators so as to indicate the work object with an identifying code. An apparatus for practicing the method using a plurality of protrusions each bearing a symbol and which can individually selectively be inverted to display an identifying code.	6
BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates generally to optical devices (elements) and, more specifically, to the design of devices based on low-dimensional semiconductor structures. [0003] 2. Description of the Prior Art [0004] Typically, quantum wells, quantum wires, and quantum dots (confined semiconductor structures) have abrupt interfaces that confine the electron and holes within. This abrupt confinement contributes to non-radiative Auger processes that severely limit the quantum efficiency of quantum well based devices (e.g., semiconductor lasers, light emitting diodes, semiconductor optical amplifiers, biological markers, etc.). [0005] In the early sixties, the one-dimensional carrier confinement achieved in semiconductor quantum wells and superlattices brought about a revolution in solid-state device technology. To fulfill the requirements of miniaturization, low power consumption, and fast operational speed, further efforts of carrier confinement in two and in three dimensions were realized with the advent of quantum wires and quantum dots. However, the application of nanostructures to real world devices has been strongly curtailed by the enhancement of dissipative Auger processes which undergird all aspects of carrier relaxation and recombination. In particular, Auger processes have been attributed to the decrease of the photoluminescence quantum efficiency in light emitting diodes, an increase in the stimulated emission threshold in lasers, and the photoluminescence degradation and photoluminescence blinking in nanocrystal (NC) quantum dots. These detrimental effects were initially explained through other mechanisms since bulk wide-gap semiconductors have negligible Auger rates due to a temperature threshold proportional to their energy gap. Eventually, it was realized that the temperature threshold was not present because, unlike the requirement in the bulk case, Auger recombination in confined structures does not require a carrier with kinetic energy comparable to the energy gap. This explained why Auger processes are very efficient in confined structures, even those fabricated from wide-gap semiconductors. [0006] Most impressively, Auger processes are visually manifest in the random intermittency observed in studies of the photoluminescence (PL) intensity emitted from a single NC. Even under constant illumination, all colloidal nanocrystals grown today exhibit this emission intermittency which has consequently been dubbed “photoluminescence blinking.” First observed about twelve years ago, the intermittency of the photoluminescence intensity came as a complete surprise in a study of a single CdSe under steady-state excitation conditions. Since then, many others have observed this effect at various temperatures in many other types of nanocrystals and nanowires. Today, the consensus is that the blinking occurs because, when illuminated, NCs can be charged (or ionized), and subsequently neutralized. Optical excitation of a neutral NC excites an electron-hole pair, which then recombines giving rise to the PL. However, if the NC is charged, the extra carrier triggers a process known as non-radiative Auger recombination during which the exciton energy is acquired by the extra charging electron or hole (see FIG. 1 ). Because the rate of Auger recombination is orders of magnitude faster than the rate of radiative recombination, photoluminescence is completely suppressed, or “quenched,” in charged NCs. BRIEF SUMMARY OF THE INVENTION [0007] The aforementioned problems are overcome in the present invention which provides a method to suppress the Auger rate in confined structures of optical devices, comprising replacing an abrupt hole confinement potential with either a smooth confinement profile or a confinement profile of a certain size found by increasing the confinement potential width until the Auger recombination rate undergoes strong oscillations and establishes a periodic minima. In addition, the present invention provides for the design of structures with high quantum efficiency. [0008] Current methods pertain to abruptly confined structures that have a large Auger rate rendering them relatively inefficient light sources (i.e., they have a relatively low ratio of output energy to pump energy). In the present invention, smoothly confined structures have reduced Auger rates, making them much more efficient than the sharply confined structures. An object of this invention is to increase the photoluminescent efficiency of active optical elements. Possible applications include, but are not limited to, designing efficient semiconductor lasers (decreasing the lasing threshold), light emitting diodes, semiconductor optical amplifiers, and the design of non-blinking biological markers. An example of non-blinking semiconductor nanocrystals can be found in Wang et al., “Non-blinking Semiconductor Nanocrystals,” Nature, 459, 686-689 (2009), the entire contents of which are incorporated herein by reference. [0009] These and other features and advantages of the invention, as well as the invention itself, will become better understood by reference to the following detailed description, appended claims, and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0010] FIG. 1 is a schematic diagram of various recombination processes of photo-excited electron-hold pairs. FIG. 1( a ) depicts a neutral structure in which photo-excited electron-hole pair recombines then radiatively emits light. If the structure acquires a positive charge, for example, then the excitation energy of the electron-hole pair is transferred to the extra hole. In this nonradiative Auger recombination process, the remnant hole will either be ejected into the continuum (shown as a sinusoidal wave) ( FIG. 1( b )) or it will remain bound inside the nanostructure should the confinement be sufficiently deep ( FIG. 1( c )). Analogously, Auger processes lead to carrier excitation in the continuum ( FIG. 1( d )) or a bound level ( FIG. 1( e )) even in the case of multiple excitons. Similar figures can be displayed for the case where the extra charge is an electron instead of a hole. [0011] FIG. 2( a ) is a semilog plot of the Auger recombination rate as a function of the confinement potential width, 2 a, for the case where the hole is ejected into the continuum (upper left). As shown in the inset, the three traces correspond to three confinement profiles, each with a fixed height of 300 meV. Accompanying dashed lines are best fits to the dependencies in the least squares sense. The Auger rate displays a successive reduction as the confinement profile is smoothed. FIG. 2( b ) is a semilog plot of the Auger recombination rate versus the confinement height calculated for the same confinement profiles, all having a fixed width of 2 a =3 nm. All quantities used are typical for AlGaInAs/InP quantum wells. [0012] FIG. 3 is a scheme for Auger rate reduction using multiple abrupt transitions in the carrier confinement potentials. FIG. 3( a ) is a confinement profile having a 1 nm core, a shell width of w 1 and a shell depth h 1 . FIGS. 3( b )-( g ) are a series of plots of the Auger rate dependence on shell thickness in decreasing increments of h 1 : in FIG. 3( b ), h 1 =150 meV; in FIG. 3( c ), h 1 =140 meV; in FIG. 3( d ), h 1 =130 meV; in FIG. 3( e ), h 1 =120 meV; in FIG. 3( f ), h 1 =110 meV; and in FIG. 3( g ), h 1 =100 meV. The general trend indicates that adding an outer shell effectively suppresses the even peaks in the Auger rate. Maximal suppression of the second peak occurs for h 1 =110 to 120 meV and an outer shell thickness of approximately 0.7 nm. DETAILED DESCRIPTION OF THE INVENTION [0013] The present invention generally relates to suppressing the nonradiative Auger decay rate in confined structures. By calculating the efficiency of Auger processes in low dimensional heterostructures that confine the free motion of the carriers, it is shown that the enhanced efficiency of Auger processes is due to the abruptness of the heterointerfaces or bounding surfaces. Therefore, the present invention discloses suppressing Auger efficiency by creating structures with a soft confinement potential. Calculations conducted in the two-band, effective mass Kane model show that smoothing out the confinement potential may reduce the rate by at least three orders of magnitude relative to the rate in structures with abruptly terminating boundaries. [0014] The rate of noradative Auger recombination can be calculated using Fermi's Golden Rule. Because highly excited final states are short-lived relative to the Auger transition time, Fermi's Rule provides a valid description of the Auger rate for a final hole state that either is bound or that resides in the continuum. [0015] When calculating the Auger rate, a major problem is encountered when obtaining an accurate estimation of the transition matrix element. After the Auger process, the extra carrier acquires a large momentum as a result of the transfer of the photoexcitation energy. Consequently, the corresponding wave function becomes rapidly oscillating within the confined volume, resulting in a matrix element that is much smaller than the average Coulomb interaction energy. Integration of the smooth ground state with the rapidly oscillating final state causes the relative diminution in the transition matrix element. [0016] From the Fourier expansion of the ground state, the leading contribution to the transition matrix element is given by the spatial frequency component, which matches the large momentum of electrons or holes in the excited final state, kF≈kf . In heterostructures, the large kF is usually generated by abrupt interfaces or surfaces. At large kF=kf 1/a, the Fourier component corresponding to the abrupt confinement potential is exponentially larger than that associated with a smooth parabolic profile. Hence, the abruptness of a confinement potential significantly increases the transition matrix element, thus accelerating the rate of Auger processes. This qualitative analysis suggests that Auger processes can be significantly suppressed in low-dimensional structures with a soft confinement potential. [0017] Moreover, Auger processes become quenched at certain sizes of the confinement potential width due to destructive interference between the initial and the final states. As the confinement potential width is increased, the calculated rate decreases overall, exhibiting very deep minima at regular widths. Such minima suggest the size of nanocrystals for which nonradiative Auger processes are strongly suppressed. [0018] In Cragg et al., “Suppression of Auger Processes in Confined Structures,” Nano Letters, Dec. 2009, the entire contents of which are incorporated by reference, the inventors investigated how confinement potential shape affects the rate of nonradiative Auger processes. If the excited carrier has sufficient energy to enter the continuum, the Auger rate is proportional to the square of Fourier amplitude of the initial, ground state evaluated at the spatial frequency of the final, excited state. Reducing the high spatial frequency components in the ground states by smoothing out the confinement decreases the Auger rate by about three orders of magnitude in comparison to an abrupt potential. [0019] In addition to smooth profiles, it may be possible to exploit the periodic nature of the Auger rate as the well width is increased. The periodic minima shown in FIG. 2( d ) may be enhanced by using a core-shell type structure as shown in FIG. 3 . As described in Cragg et al., “Suppression of Auger Processes in Confined Structures,” Nano Letters, Dec. 2009, the Auger recombination rate undergoes strong oscillations as the confinement width is increased. This can allow fabrication of NC having certain sizes that exhibit significant Auger recombination rate suppression. Such approaches can be utilized in engineering non-blinking nanocrystals for use in biological and optoelectronic applications requiring high quantum efficiency. Softening the confinement potential can also be used for engineering tunable, low threshold lasers and LEDs with high quantum yields based on quantum wells and quantum wires of wide gap semiconductors. [0020] The above descriptions are those of the preferred embodiments of the invention. Various modifications and variations are possible in light of the above teachings without departing from the spirit and broader aspects of the invention. It is therefore to be understood that the claimed invention may be practiced otherwise than as specifically described. Any references to claim elements in the singular, for example, using the articles “a,” “an,” “the,” or “said,” is not to be construed as limiting the element to the singular.	The present invention is generally directed to a method of suppressing the Auger rate in confined structures, comprising replacing an abrupt confinement potential with either a smooth confinement potential or a confinement potential of a certain size found by increasing the confinement potential width until the Auger recombination rate undergoes strong oscillations and establishes a periodic minima. In addition, the present invention provides for the design of structures with high quantum efficiency.	7
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical mechanical polishing (CMP) apparatus used for manufacturing a semiconductor device and a polishing cloth for use with the apparatus. The invention relates particularly to a CMP apparatus for minimizing deterioration in the polishing performance of the polishing cloth and allows easy detection of its useful operational limit. 2. Description of the Related Art Today as the number of layers of large scale integrated circuits (LSI) and the density of such circuits increases, the use and development of improved polishing and smoothing techniques for interlayer insulation films becomes critically important. At present, chemical mechanical polishing (CMP) is widely recognized for smoothing and final preparation of a semiconductor wafer. FIG. 5 shows the general configuration of a CMP apparatus. This apparatus comprises at least a rotatable ring 3 for fixing and rotating a semiconductor substrate 1, a polishing cloth 5 for polishing the surface of the semiconductor substrate 1 and a turntable 7 for fixing and rotating the polishing cloth 5. During the formation of a semiconductor substrate, surface irregularities are usually created which need to be removed. After semiconductor substrate 1 is received, rotatable ring 3 forces surface 1 against cloth 5 and ring 3; turntable 7 is then rotated and abrasive fluid 9 is supplied. As a result, the surface of the semiconductor substrate 1 is smoothed by mechanical polishing and chemical reactions. For effective polishing, the cloth must have an abrasive quality. The CMP apparatus utilizes a process called dressing to maintain the polishing performance of the polishing cloth. Dressing restores the abrasiveness of a dull polishing cloth. The cloth becomes dull as it is used; its dullness is proportional to the number of times it is used on semiconductor substrates. FIG. 6 shows the operation of a dresser during the dressing process. Dresser 11, containing a diamond granular surface, is pressed against the surface of the polishing cloth 5 fixed to turntable 7; dresser 11 and polishing cloth 5 respectively rotate during the dressing operation. Alternatively, the dresser 11 itself may be moved horizontally in order to completely cover the surface of the polishing cloth. FIG. 7 is an enlarged view of dresser 11. An abrasive diamond granular surface 13 is formed by a mixture of abrasive diamond grains on an annular region of dresser 11. Diamond grain surface 13 is pressed against the surface of the polishing cloth during the dressing. In accordance with the invention described below, dressing may be performed simultaneously during the semiconductor substrate polishing. Alternatively, it may be performed before or after the substrate polishing. FIG. 8 is a diagram showing the practical configuration of a general CMP apparatus. The surface of polishing cloth 5 has an abrasive surface comprising, for example, dimples or lattice grooves for distributing an abrasive fluid 9 along the entire surface of polishing cloth 5. As the polishing cloth processes more and more area of substrate 1, the cloth becomes worn and thin. When the wear on the polishing cloth 5 exceeds a particular limit, both the polishing speed and the uniformity of the polishing will deteriorate. Therefore, a test board, made of a sample semiconductor substrate, has been used in the prior art to detect the wear of the cloth; it assists in determining whether it has reached a use limit indicating the cloth is no longer effective for polishing. The polishing speed and the surface polishing uniformity are calculated during this inspection process; accordingly, it can be determined whether the polishing cloth 5 has exceeded its use limit. Upon determining that the cloth has not reached the use limit, the CMP apparatus can then be used to polish substrate 1; polishing cloth 5 is replaced, however, upon exceeding its use limit. During dressing, abrasive diamond grains may fall off the diamond surface and onto the cloth; as a result, the fallen grains may damage the surface of the semiconductor substrate during subsequent polishing operations. FIGS. 9 is a cross section of the abrasive diamond granular surface 13 shown in FIG. 7. As shown in FIG. 9(a), diamond grains 17 are embedded in a nickel layer 19 of surface 13 for dressing the polishing cloth. As shown in FIG. 9(b), friction created by the contact of surface 13 and the polishing cloth 5 during dressing causes diamond grains 17 to fall off nickel layer 19 and drop onto cloth 5. As shown, nickel layer 19 becomes thinner as it is scoured during dressing and grains 17 fall from the surface. Some diamonds are more susceptible to loosening and falling because their area contacting nickel layer 19 is small and thereby may be more easily removed during the dressing operation. As a result, diamond grains 17 fall off continuously. The presence of extraneous fallen diamond grains on the polishing cloth will potentially destroy the substrate during the polishing step. In addition, the use of a test board has associated problems. First, the use of test boards necessarily results in a waste of semiconductor substrates since they must be abandoned after their temporary use. Second, since the size of the test board substrate must be commensurate with the semiconductor substrate used in production, the subsequent discarding of the board results in further waste and costs. Further, the time required for test board processing and evaluation is problematic counterproductive in attempting to improve manufacturing efficiency in a production line. SUMMARY OF THE INVENTION An object of the present invention is to provide a CMP apparatus which avoids damage to the surface of a semiconductor substrate by removing abrasive grains which have fallen onto the surface of the polishing cloth before actual polishing begins. Another object of the invention is to provide a CMP apparatus and polishing cloth which readily identifies the use limit of a polishing cloth without the need for a test board. The present invention provides a dresser in a chemical mechanical polishing apparatus comprising a surface facing a semiconductor substrate, an annular abrasive grain surface on the periphery of the surface, and a particle remover located within an area surrounded by the annular abrasive grain surface. The present invention provides a chemical mechanical polishing apparatus comprising a rotatable ring for holding a semiconductor substrate, a polishing cloth on a turntable, facing the semiconductor substrate, a dresser adjacent the rotatable ring and the facing polishing cloth. The dresser also includes an abrasive grain annulus; and a particle remover surrounded by the abrasive grain annulus. The present invention provides a method for removing abrasive grains on a polishing cloth in a CMP apparatus having a rotatable ring for receiving a semiconductor substrate, a polishing cloth on a turntable facing the rotatable ring, a dresser adjacent the rotatable ring and facing the polishing cloth; the dresser having an abrasive grain annular surface and a particle remover surrounded by the abrasive grain annular surface. The method comprising the steps of dressing the polishing cloth, and removing abrasive grains on the polishing cloth while performing the dressing step. The present invention provides a polishing cloth for a CMP apparatus comprising a polishing cloth and a concavity on the polishing cloth for holding a use limit indicator. The present invention provides a CMP apparatus comprising a rotatable ring for receiving a semiconductor substrate, a polishing cloth on a turntable facing the rotatable ring, and a concavity on the polishing cloth for holding a use limit indicator. The present invention provides a method for detecting a use limit of the polishing cloth in a CMP apparatus, comprising the step of detecting a use limit indicator embedded in a concavity on a polishing cloth. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a general configuration of a CMP apparatus according to an embodiment according to the present invention. FIG. 2 is an enlarged view of the diamond dresser shown in FIG. 1. FIGS. 3(a) and 3(b) are enlarged views of the polishing cloth shown in FIG. 1. FIGS. 4(a) and 4(b) are diagrams showing the results of actual polishing using the polishing cloth of FIG. 3. FIG. 5 shows the configuration of a general CMP apparatus. FIG. 6 shows the diamond dresser and the polishing cloth during a dressing operation. FIG. 7 is an enlarged view of the diamond dresser shown in FIG. 6. FIG. 8 shows the configuration of another general CMP apparatus. FIGS. 9(a) and 9(b) are cross sectional views of the abrasive grain surface shown in FIG. 7. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a general configuration of a CMP apparatus according to the present invention. The components shown in FIGS. 5-9 are provided with the same reference numerals. The CMP apparatus comprises a rotatable ring 3 which receives, holds and rotates a semiconductor substrate 1; facing substrate 1 is a polishing cloth 5 for polishing the surface of semiconductor substrate 1 and a turntable 7 which receives, holds and rotates polishing cloth 5. The surface of semiconductor substrate 1, which has surface irregularities after the manufacturing processes, is pressed against polishing cloth 5. Ring 3 and turntable 7 are rotated while being supplied with abrasive fluid 9. The surface of semiconductor substrate 1 is thereby smoothed due to the mechanical polishing and the concomitant chemical reactions. Positioned adjacent semiconductor substrate 1 is a diamond dresser 11. Diamond dresser 11 is pressed against the surface of polishing cloth 5, and is rotated for restoring the abrasiveness of polishing cloth 5 during rotation of polishing cloth 5. This restoring step is needed to maintain the polishing performance of cloth 5 since it will become dull as a number of semiconductor substrates are treated over time. FIG. 2 is an enlarged view of the diamond dresser 11 shown in FIG. 1. The components shown in FIGS. 5-9 are provided with the same reference numerals. Diamond dresser 11 according to the present invention comprises an abrasive annulus 13 (e.g., diamond granular) and a particle remover 15 comprising material for mechanically removing particles, such as abrasive diamond grains that fall onto the polishing cloth. Particle remover 15 comprises a nylon brush positioned concentrically within the abrasive annular surface 13. Since particle remover 15 removes the abrasive grains that have fallen onto the polishing cloth during dressing or moves them to an area not used for polishing, the semiconductor surface can be kept free from flaws caused by loose abrasive grains. Alternatively, some abrasive grains are removed from the surface of the cloth because they adhere to the brush. Since the diamond dresser incorporates a remover, diamond grains can be removed at the same time as dressing is performed. Therefore, remover 15 can reduce the total processing time because no additional time is required to remove any loose grains. Remover 15 may also comprise a sponge or a mohair brush. When using a mohair brush good particular removal can be obtained since no additional pressure is required; a mohair brush is softer than using a nylon brush. It is desirable that the remover have a diameter at least as large as the diameter of semiconductor substrate 1. When diamond dresser 11 is swung into position during the dressing process, the remover needs to have at least a diameter which is sufficient for contacting the entire area used for polishing. This will allow more effective removal of the loose abrasive grains. According to the present invention, dresser 11 can remove the abrasive grains that have fallen onto the polishing cloth 5 at the same time as the dressing operation is performed. This reduces both processing time and cost. FIG. 3 is an enlarged view of the polishing cloth 5 of FIG. 1. FIG. 3(a) is a plan view and FIG. 3(b) is a partial cross sectional view taken along line A-A'. The parts contained in the FIGS. 5-9 are provided with the same reference numerals. Polishing cloth 5, according to the present invention, has concavities on the surface, such as dimples or lattice grooves. In addition to its uniform standard concavities, polishing cloth 5 has at least one shallow concavity. This shallow concavity is used as a use limit indicator 21. As cloth 5 becomes thinner while treating more and more semiconductor substrates 1, use limit indicator 21 gradually appears to approach the surface. By visually checking this indicator, the use limit of the polishing cloth 5 can be easily detected. Therefore, the need for the prior art test polishing process and test boards become unnecessary. Consequently, both processing time and cost are reduced. Use limit indicator 21 can be easily fabricated since it is made, in part, from the same material as polishing cloth 5. For example, indicator 21 may be provided by embedding a different material in a shallow concavity of polishing cloth 5. FIG. 4 are diagrams showing the actual polishing results of the semiconductor substrate using the polishing cloth 5 of FIG. 3. FIG. 4(a) shows the polishing results of a semiconductor substrate deposited with an oxide film having a thickness of 0.6 μm and FIG. 4(b) shows the polishing results of a semiconductor substrate deposited with a polysilicon film having a thickness of 0.5 μm. In FIGS. 4(a) and 4(b), the horizontal axis indicates the number of polished semiconductor substrates and the vertical axis shows the polishing speed and the surface polishing uniformity. Polishing cloth 5 is made of polyurethane with a thickness of about 1.3 μm and use limit indicator 21 has a thickness of 0.5 μm. As shown in FIG. 4(a), when a silicon substrate has a 0.6 μm thick oxide film, the polishing speed declines and the surface polishing uniformity deteriorates rapidly after the polishing cloth 5 has polished approximately 600 substrates. At this time, the use limit indicator 21 can be used (as shown) to easily detect that the polishing cloth 5 must be replaced. And, as shown in FIG. 4(b), when a silicon substrate has a 0.5 μm thick polysilicon film, the polishing speed declines and the surface polishing uniformity deteriorates rapidly when the cloth has polished approximately 900 semiconductor substrates. At this time, the use limit indicator 21 can also be used (as shown) to detect that the polishing cloth 5 must be replaced. As described, the use limit indicator on polishing cloth 5 can be easily detected without the need for conventional test polishing steps. Therefore, the use of test boards which are later discarded become unnecessary and a shorter processing time is obtained while reducing overall processing costs. In the above description, the material of the polishing cloth 5 is described to be polyurethane, however, the present invention can be applied to all polishing cloth materials used for polishing semiconductor substrates. For example, nylon or rayon can also be used. The use limit indicator 21 is designed to have a thickness so that it visually appears on the polishing cloth surface at the point when the polishing speed and/or the surface polishing uniformity deteriorates. In the above description, the use of silicon substrates deposited with an oxide film and/or polysilicon film has been described, the present invention may also be applied to the polishing of film forming materials generally used in the LSI processes such as high melting point metals (including for example, Si, Mo, W, Ti, and Ta) and their oxides, nitrides and suicides, as well as metal wiring materials (including for example, Al, Cu, Al--Si--Cu and Al--Cu). While a presently preferred embodiment of the invention has been described, those of ordinary skill in the art will be enabled to contemplate variations from the information given in the disclosure. Such variations are intended to fall within the scope of the present invention. Such variations may be made in the structure of the various parts and methods without functionally departing from the spirit of the invention. For example, the dressing and polishing steps can be carried out simultaneously. In addition, while the dresser and particle remover are shown on one integral structure,they may be separated. In that case, the particle removing operation can be performed during or after the dressing operation. Further, while the dresser has an annular shape and operates with circular motion, other shapes are contemplated with other motions such as, for example, a series of horizontal movements. In that case, the particular remover will then brush the surface in one of a number of pattern movements to cleanse abrasive particles from the polishing cloth.	The present invention provides a CMP apparatus for minimizing the deterioration of the polishing performance and allows easy detection of the its useful operational limit. The CMP apparatus for polishing of the semiconductor substrate is provided with a dresser for removing abrasive grains which have fallen onto the polishing cloth. A particle remover is provided for easily removing abrasive grains at approximately the same time or at a different time as the dressing process. The polishing cloth includes a use limit indicator formed in a concavity of the cloth. Upon the exposure of the use limit indicator, the limit of the polishing cloth can be easily detected.	1
FIELD OF THE INVENTION [0001] The invention relates to electrical cabling. More particularly, the invention relates to reducing crosstalk in electrical cabling by effectively increasing the spacing for optimum pair separation. Moreover, pair separation is achieved by inducing a corrugated configuration into a bisector tape. BACKGROUND OF THE INVENTION [0002] In the communication industry, the reduction of crosstalk in electrical cables is an ongoing problem. Often an electrical cable will contain a plurality of twisted pairs of individually insulated conductors. In the past, many configurations and techniques have been implemented to reduce crosstalk between the respective electrically conducting pairs. [0003] For example, one of the most useful techniques for reducing crosstalk within electrical cabling includes physically separating the twisted pairs within the cable. In this manner, numerous components such as spacer elements, flat bisector tapes, convex tapes, crosswebs or other filler elements have been used to increase pair separation and improve crosstalk. See, e.g., U.S. Pat. Nos. 4,920,234 and 5,149,915. Because typical communications industry electrical cables include four twisted pairs, many spacer element configurations comprise one or more centrally-located spacer elements, such as a dielectric flute, with the twisted pairs arranged in various configurations therearound. See, e.g., U.S. Pat. Nos. 5,132,488 and 5,519,173. [0004] However, these methods and cable arrangements aimed at reducing crosstalk are often burdened with other problems. For example, existing spacer elements are relatively inflexible and thus restrict movement of the twisted pairs within the electrical cable. Also, existing spacer elements are relatively expensive and difficult to handle and manipulate during the electrical cable manufacturing process. [0005] One simple way in which the spacing can easily be increased between twisted pairs is the addition of more material. In this regard, the thickness of the tape is increased to a desired thickness and/or stiffness. However, simply increasing the thickness of the tape often has negative implications, such as over-stiffening the tape, degrading the burn performance of the cables by the addition of too much material, or significantly increasing the cost of manufacturing the cables. [0006] Efforts to improve the crosstalk performance of cables have generally involved incorporating additional separation between pair units. This additional separation is achieved and maintained with the use of flat, cross-shaped or semi-circled tape or flutes between or around the twisted pair units. Some manufacturers may also jacket one or more of the pair cables and then surround the jacketed cables with another jacket in particularly large cables, such as 25 pair LAN cables. These methods of inducing increased separation between pair units introduce an additional cost factor, inflexibility and manufacturing complexity into the electrical cables. [0007] Thus, a heretofore unaddressed need exists in the industry to have electrical cabling that addresses the aforementioned deficiencies and inadequacies. SUMMARY OF THE INVENTION [0008] The present invention is embodied in an electrical cable having a plurality of twisted pairs. In one example embodiment, the cable has four ( 4 ) twisted pairs, although it is to be understood that the invention can be used with other numbers of twisted pairs. The cable is configured to have four twisted pairs with a corrugated tape separating at least two of the twisted pairs from the other twisted pairs. The corrugation of the tape comprises shaping the tape into folds of parallel and alternating ridges and grooves. A longitudinal tape runs the length of the cable so as to separate and maintain at least one or more of the twisted pairs from the remaining twisted pairs that are adjacent thereto. [0009] The tapes may be comprised of, for example, polypropylene (PP), fire retardant polypropylene (FRPP), or low-smoke polypropylene (LSPP), or any other suitable material and may be comprised of varying thicknesses. In one example embodiment, the corrugated tape is comprised of LSPP having a thickness of approximately 8 to approximately 12 mils and a width of approximately 0.12 to approximately 0.40 inches. However, other suitable materials, thicknesses and widths may also be used. Along the longitudinal direction of the tape, corrugating of the tape is provided to increase the spacing and stiffness properties of the tape without substantially increasing the amount of material used in the manufacture of the tape. In one embodiment, the length of the corrugation from ridge peak to ridge peak along the longitudinal direction of the tape should be less than approximately 0.12 inches. In this manner, the effective spacing between the twisted pairs is optimized for improved crosstalk performance and satisfaction of fire safety requirements. [0010] In another example embodiment of the invention, the tape is corrugated across its width such that the spacing and stiffness properties of the tape are increased without increasing the linear amount of material used in the manufacture of the tape. For one embodiment of the tape corrugated across its width, an initial sufficient width of tape should be used, such that once corrugated, the width corrugated tape has a final width of approximately 0.12 to approximately 0.40 inches. In one embodiment, the length of the corrugation from ridge peak to ridge peak for corrugation across the width of the tape should be less than approximately 0.06 inches. In this manner, the effective spacing between the twisted pairs is optimized for improved crosstalk performance and satisfaction of fire safety requirements. [0011] In all of the embodiments of the present invention, the flexibility of the cable is maintained with the corrugated tape in place, and substantial improvement in the minimum power sum crosstalk margin is realized. The corrugated separator tape can be made of various materials so long as appropriate care in the selection thereof is taken. In the case where a fire retardant cable is desired, the use of a corrugated tape can provide a sufficient mil spacing so as to meet certain electrical requirements, while simultaneously reducing the amount of tape material normally required by a flat tape to achieve equivalent electrical specifications. In this regard, the amount of tape material is sufficiently reduced so that the bum test of the cable is satisfied by using a corrugated tape of a smaller mil than would be satisfied by using a flat tape equivalent to the thickness of the dimensions of the corrugated tape. [0012] Other systems, methods, features, and advantages of the present invention will become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be within the scope of the present invention, and be protected by the claims. BRIEF DESCRIPTION OF THE DRAWINGS [0013] Many aspects of the invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. [0014] [0014]FIG. 1 is a cross-sectional view of a prior art four pair cable with a cross shaped spacer; [0015] [0015]FIG. 2 is a cross-sectional view of a prior art four pair cable with a semi-circled shaped spacer; [0016] [0016]FIG. 3 is a side view of a length of corrugated tape; [0017] [0017]FIG. 4 is a cross-sectional view of a cable incorporating the corrugated tape as a spacer between twisted pairs; [0018] [0018]FIG. 5 is a perspective, break out view showing the longitudinal corrugation of the tape in an electrical cable; [0019] [0019]FIG. 6 is a cross-sectional view of a cable showing another embodiment of the invention in which the tape is corrugated along its width; and [0020] [0020]FIG. 7 is a perspective, break out view showing the width corrugation of the tape in an electrical cable. DETAILED DESCRIPTION [0021] Electrical cabling such as that used in communication networks continues to suffer adversely from the reactive effects of parallel and adjacent conductors, i.e., inductive and capacitive coupling, also known as “crosstalk.” Typically, electrical cabling includes a jacket containing a plurality of twisted pairs of individually insulated conductors. As the number of twisted pairs within an electrical cable increases and/or the twisted pairs are placed closer together, the potential for crosstalk interference increases. [0022] Crosstalk becomes more severe at higher frequencies, at higher data rates, and over longer distances. Thus, crosstalk effectively limits the useful frequency range, bit rate, cable length, signal to noise (S/N) ratio and number of conductor pairs within a single electrical cable for signal transmission. Additionally, crosstalk is often more pronounced in bidirectional transmission cables. Such effect is known as “near end crosstalk” (NEXT), and is particularly noticeable at either end of the cable where signals returning from the opposite end are weak and easily masked by interference. [0023] In general, crosstalk is better controlled by separating parallel and adjacent transmission lines or by transposing the signals along the cable to minimize the proximity of any two signals. However, one of the easiest ways to reduce crosstalk involves increasing the amount of space or separation between the twisted pairs in the cable. As the spacing increases, the severity of the crosstalk decreases a calculable amount. [0024] Accordingly, as shown and discussed herein, many electrical cable arrangements exist that include spacer elements for maintaining sufficient separation between the conducting pairs and thus reducing crosstalk therebetween. [0025] Referring now to FIG. 1, shown is a prior art electrical cable 20 having an arrangement aimed at reducing crosstalk. The electrical cable 20 comprises a jacket 12 , made of a suitable polymeric material, surrounding four pairs of individually insulated conductors or conductive elements 14 separated by a spacer 16 . The individually insulated conductor pairs 14 are typically comprised of twisted pairs of copper wire or fiber optic material, and the spacer 16 is typically comprised of a suitable dielectric material such as polyvinyl chloride (PVC). [0026] In operation, the spacer means 16 separates the conductor pair 14 and maintains substantially constant spacing between the conductor pairs 14 along the length of the electrical cable 20 . In this manner, the separation of the conductor pairs 14 results in increased crosstalk performance. [0027] Although conventional spacer 16 and conductor pairs 14 arrangements may reduce crosstalk to a certain degree, many of these conventional cable arrangements are often burdened with other problems, as discussed previously herein. For example, many spacers 16 are relatively inflexible and thus restrict movement of the conductor pairs 14 within the electrical cable 20 . Also, the inflexibility of the spacer 16 makes it difficult to handle and incorporate into electrical cables 20 during manufacturing. Furthermore, many spacers 16 are relatively expensive and contribute significantly to the overall cost of the cable 20 . The expense of the spacer 16 is particularly important when, in order to satisfy certain electrical requirements, the thickness of the spacer 16 must be increased to provide sufficient separation between the conductor pairs 14 . Additionally, the increase in the thickness or amount of material in the spacer 16 may cause the cable 20 to fail fire safety requirements. This is particularly applicable for cables that must meet plenum (CMP) and/or Nonhalogen IEC 60332 Part 3C fire safety ratings. [0028] Referring now to FIG. 2, a prior art electrical cable 20 is shown in which the electrical cable 20 includes a jacket 12 formed around a plurality of pairs of individually insulated conductors or conductive elements 14 , typically four pairs, as shown. The jacket 12 is made of any suitable flexible, electrically insulating material, e.g., a fluoropolymer, polyvinyl chloride (PVC), a polymer alloy or other suitable polymeric material. The conductor pairs 14 , which are typically twisted pairs of copper wire or fiber optic material, are individually insulated with a suitable polymeric material, e.g., polyolefin, flame retardant polyolefin, fluoropolymer, PVC or a polymer alloy. [0029] As shown in FIG. 2, it is known in the prior art to maintain the spacing between the conductor pairs 14 by a dielectric film or tape 22 advantageously positioned around particular conductor pairs 14 . The dielectric film 22 is comprised of a suitable electrically insulating material, such as Kapton® film (polyamide) woven glass yarn tape, ethylchlorotrifluoroethylene (ECTFE or Halar®), polyvinyl chloride (PVC), polyolefins and fluoropolymers including fluorinated ethylene-propylene (FEP or Teflon®), perfluoroalkoxy polymers of tetrafluoroethylene and either perfluoropropyl ether (PFA) or perfluoromethylvinyl ether (MFA). The thin dielectric film 22 has a flexible construction that does not significantly affect the flexibility of the electrical cable 20 . However, the placement of the semi-circular configured dielectric film 22 around alternating conductor pairs 14 (e.g. the first and third pairs) is advantageous in that it reduces crosstalk by maintaining separation between the conductor pairs 14 . In this manner, the spacing between adjacent conductor pairs 14 is substantially constant along the length of the cable and the conductor pairs 14 are separated to the extent that the conductor pairs generally occupy separate quadrants within the electrical cable 20 . [0030] [0030]FIG. 3 depicts a side view of a corrugated tape 30 in accordance with a first example embodiment of the present invention. In this regard, it is shown that a bisector tape 30 is corrugated as opposed to being a flat tape. The bisector tape 30 preferably is comprised of a material that is amenable to corrugation, i.e., shaping into folds of parallel and alternating ridges and grooves. The corrugation length 31 is defined as the distance from ridge peak to ridge peak. In this manner, the corrugated tape 30 achieves an effective thickness 32 that exceeds the actual thickness 34 of the tape material itself. This effective thickness 32 allows a manufacturer to use a smaller mil of tape material and still achieve a degree of separation that would have been achieved using a thicker mil tape. The ability to use a smaller mil tape to achieve a larger effective thickness 32 is beneficial in that it utilizes significantly less material than achieving the same thickness by increasing the actual thickness 34 of the tape. The use of less material to achieve the same separation of the conductor pairs 14 results in savings in manufacturing costs and does not degrade the burn performance of the cable 20 . [0031] For example, if the electrical requirements of an electrical cable 20 require a 15 mil spacing between the conductor pairs 14 , but the cable 20 is failing the fire safety burn test because of the thickness of the bisector tape, the corrugated tape 30 may be used. In this respect, a 10 mil tape, which would pass the burn test, is corrugated to a 15 mil specification or effective thickness 32 . Thus, a corrugated 10 mil tape can be used in place of the 15 mil tape, thereby saving material costs and satisfying the fire safety bum tests. [0032] As shown in FIG. 4, in cross-section, the longitudinally corrugated bisector tape 30 appears as a separator, spacing two conductor pairs 14 in a typical four pair cable 20 from the other two conductor pairs 14 in this example. In FIG. 5, the perspective view of an electrical cable containing a longitudinally corrugated bisector tape 30 is shown. The corrugation extending along the length of the bisector tape 30 increases the actual thickness 34 of the bisector tape 30 to an effective thickness 32 in order to separate and maintain two pairs of conductors 14 from the remaining two pairs of conductors 14 . Additionally, the corrugation increases the stiffness across the tape 30 , adding to the stability of the tape and the maintenance of the degree of separation of the pairs of conductors 14 . It is anticipated, however, that the stiffness of the corrugated tape 30 is such that the tape 30 is capable of bending or flexing along either its length or width, thus permitting the tape 30 and the electrical cable into which it is incorporated to be bent or flexed if desired. In this manner, the spacing of the conductor pairs 14 effectively reduces crosstalk and increases crosstalk performance as measured on a decibel (db) per dollar basis for the costs associated with the tape. [0033] The corrugated bisector tape 30 preferably extends the length of the conductor pair units 14 in the length of the electric cable 20 . The tape 30 may include any of a number of materials such as flexible, dielectric materials (including, for example, polypropylene tape, a polyimide woven glass yarn tape, such as Kapton®, polyvinyl chloride, or any of several polyolefins and/or fluoropolymers, or any of several other insulating materials, including fire retardant materials, such as fire retardant polypropylene), or any other suitable material. In a preferred embodiment, the corrugated tape 30 is comprised of LSPP having a thickness of approximately 8 to approximately 12 mils, a width of approximately 0.12 to approximately 0.40 inches, and a corrugation length 31 of approximately 0.12 inches from ridge peak to ridge peak. [0034] The corrugated tape 30 , by maintaining the separation between adjacent twisted pairs 14 , has been found to be an economically advantageous mechanism of reducing crosstalk in a cable structure. Additionally, the suppleness of the tape 30 allows it to flex easily when, for example, the cable 20 is bent or twisted. However, the corrugation also provides stiffness across the tape 30 such that its strength properties are increased, which, in turn, increases the strength properties of the cable. Furthermore, if increased separation between adjacent pairs 14 is desired, more than one corrugated tape 30 may be used in the cable 20 . For instance, two corrugated tapes 30 may be used to achieve separation between each of a four, twisted pair cable 20 . Additionally, one or more corrugated tapes 30 may be used in a cable 20 in combination with other types of tapes or separating devices as are known and used in the art, in order to achieve desired electrical performance and characteristics. It has further been found that the electrical performance of the cables of the invention, as depicted in FIGS. 4 - 7 , compares favorably with electrical cables of the type shown in FIGS. 1 and 2, as well as others, with the added advantages of flexibility and economy of fabrication. [0035] In accordance with another example embodiment of the invention shown in FIGS. 6 - 7 , the corrugation of the bisector tape 36 is configured across the width of the tape. In this respect, the corrugated tape 36 still maintains the increased effective thickness 32 without increasing the actual thickness 34 of the tape 36 , thus resulting in an overall reduction in the amount of spacing materials necessary to achieve certain electrical requirements. This width corrugating embodiment also maintains the strength and stiffness properties that were discussed above with respect to the longitudinal corrugation. In addition to the overall reduction of spacing materials, the width corrugated tape 36 offers the added benefit of manufacturing ease, because the length of tape 36 necessary to run the length of the conductive pairs 14 of the cable 20 does not require adjustment for the loss of length due to longitudinal corrugation. [0036] The embodiment of the invention depicted in FIGS. 6 - 7 is, except for the direction of corrugation of the bisector tapes 30 and 36 and a corrugation length 31 of approximately 0.06 inches from ridge peak to ridge peak, substantially similar to that shown in FIGS. 4 - 5 . More particularly, the operative results are substantially the same, i.e., advantageously providing economics of manufacture, greater flexibility in spacing design, and optimization of separation and maintenance of spacing between conductor pairs 14 for increased crosstalk performance. [0037] It should be emphasized that the above-described embodiments of the present invention, are only possible examples of implementations, merely set forth for a clear understanding of the principles of the invention. Many variations and modifications may be made to the above-described embodiment of the invention without departing substantially from the spirit and principles of the invention. All such modifications and variations are within the scope and the present invention.	An electrical cable having a plurality of twisted pairs of conductors therein and a corrugated tape member that separates and maintains spacing of said twisted pairs from adjacent twisted pairs. The corrugated tape member is preferably comprised of a dielectric material and said corrugation may be longitudinal or across the width of said tape member. The corrugated tape member permits the use of a thinner mil tape while achieving sufficient spacing between the twisted pairs and maintaining cable flexibility so as to significantly improve crosstalk and reduce manufacturing costs and difficulties associated with thicker mil flat tape or fluting.	7
CROSS-REFERENCE TO RELATED APPLICATION This is a continuing application, under 35 U.S.C. § 120, of copending international application No. PCT/EP2003/007722, filed Jul. 16, 2003, which designated the United States; this application also claims the priorities, under 35 U.S.C. § 119, of German patent application No. 102 37 512.7, filed Aug. 16, 2002, German patent application No. 102 50 894.1, filed Oct. 31, 2002, and German patent application No. 103 14 085.9, filed Mar. 28, 2003; the prior applications are herewith incorporated by reference in their entirety. BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a metallic honeycomb body, in particular to a honeycomb body for an exhaust system of an internal combustion engine. Such honeycomb bodies are used as carriers for catalytically active material and/or for adsorber material and similar applications. Metallic honeycomb bodies which are used in particular for the purification of exhaust gases in internal combustion engines have to satisfy very different demands, and in some cases compromises have to be made between contradictory requirements. First of all, honeycomb bodies of that type should provide the maximum possible surface area at which the desired catalytic reactions or adsorption processes can take place. In many applications, a low heat capacity is desired, so that the honeycomb body is either quickly heated to its desired operating temperature or should also have a high heat capacity, so that it can remain at operating temperature for a longer time but cannot be heated to excessively high temperatures too quickly. Of course, a configuration of that type must in general terms be mechanically stable, i.e. must be able to withstand a pulsating gas flow as well as mechanical loads caused by movement of the vehicle. The material of the honeycomb bodies must be resistant to high-temperature corrosion and it must also be possible to machine the material in such a way that the desired honeycomb structures can be produced easily and at low cost. In many cases, particular structures are also required within the honeycomb body in order to influence flow, for example to improve contact with the surface or to effect cross-mixing. Finally, it must be possible for a suitable honeycomb body to be produced at low cost in mass production. Individual aspects of the above-mentioned problems have been described extensively in numerous documents which form part of the prior art. A distinction is drawn in particular between two typical forms of metallic honeycomb bodies. An early form, of which German Published, Non-Prosecuted Patent Application DE 29 02 779 A1, corresponding to U.S. Pat. No. 4,273,681, shows typical examples, is the helical form in which substantially one smooth and one corrugated sheet-metal layer are laid on top of one another and are wound helically. In another form, the honeycomb body is composed of a multiplicity of alternately disposed smooth and corrugated or differently corrugated sheet-metal layers, with the sheet-metal layers initially forming one or more stacks which are wrapped together. In that case, the ends of all of the sheet-metal layers come to lie on the outside and can be connected to a housing or tubular casing, resulting in numerous connections, which increase the durability of the honeycomb body. Typical examples of those forms are described in European Patent 0 245 737 B1, corresponding to U.S. Pat. No. 4,832,998, or International Publication No. WO 90/03220, corresponding to U.S. Pat. No. 5,105,539. It has also long been known to equip the sheet-metal layers with additional structures in order to influence the flow and/or to achieve cross-mixing between the individual flow passages. Typical examples of configurations of that type are International Publication Nos. WO 91/01178, corresponding to U.S. Pat. No. 5,403,559; WO 91/01807, corresponding to U.S. Pat. No. 5,045,403; and WO 90/08249, corresponding to U.S. Pat. No. 5,157,010. Finally, there are also honeycomb bodies in conical form, if appropriate, which include further additional structures for influencing flow. A honeycomb body of that type is described, for example, in International Publication No. WO 97/49905, corresponding to U.S. Pat. No. 6,190,784 B1. Furthermore, it is also known to form a recess for a sensor, in particular for accommodating a lambda sensor, in a honeycomb body. One example thereof is described in German Utility Model DE 88 16 154 U1. It has also long been known to use slotted metal sheets, in particular expanded metal and similar slot structures, for honeycomb bodies. An overview of various forms and configurations of openings in sheet-metal layers of catalyst carrier bodies is given in U.S. Pat. No. 5,599,509 together with the prior art cited therein. That device makes targeted use of openings to reduce heat capacity in a front region of a honeycomb body as compared to a rear region. Although the extensive prior art allows many different directions to be pursued in development, some further development trends have emerged. One of those trends is the development toward ever thinner metal foils in order to be able to provide a large surface area while using small amounts of material and achieving a low heat capacity. A clear drawback of that development trend is that the thin foils become increasingly mechanically sensitive and the honeycomb bodies produced therefrom are less durable. At the same time, a trend has evolved toward ever higher cell densities, which to a certain extent is caused by the ever thinner foils being used. In order to improve mass transfer with the surfaces of a honeycomb body, structures for influencing flow were introduced into the surfaces, in particular what are known as transverse structures, or flow-guiding surfaces or additional inflow edges were created in the interior of a honeycomb body. Although the advantages of openings in the sheet-metal layers for cross-mixing are known, the systematic provision of openings through which a fluid can freely pass in the majority of the catalytic converter volume has not heretofore been considered in practice, since that runs contrary to the trend toward providing ever greater surface areas within increasingly small volumes. While slots and/or flow-guiding surfaces and similar structures do not reduce the surface area in a honeycomb body, the use of a large number of holes does considerably reduce the surface area and, moreover, at least if the holes are formed by removing material, means an increased consumption of starting material without a corresponding increase in surface area, which likewise runs contrary to prevailing trends. Therefore, holes have only been considered if they are supposed to have a specific function at a certain location in the honeycomb body, for example the function of cross-mixing or reducing the heat capacity compared to other regions. Although that consideration, when seen in isolation, was certainly applicable to a metallic honeycomb body, one should not lose sight of the fact that a metallic honeycomb body is subsequently coated with a coating material, which in many cases also contains expensive precious metals as a catalytically active component. Consequently, a large surface area always also means a large quantity of expensive coating material. Surprisingly, tests have shown that for certain dimensions of size, distribution and density of a large number of holes over a honeycomb body, the catalytic conversion properties can be as good, with a smaller surface area, as in a honeycomb body without holes and with a larger quantity of coating material. SUMMARY OF THE INVENTION It is accordingly an object of the invention to provide a metallic honeycomb body having at least partially perforated sheet-metal layers, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and which, by virtue of having a suitable number, dimensions and distribution of holes, is particularly suitable as a carrier for a coating, in particular for economical deployment of a coating material. With the foregoing and other objects in view there is provided, in accordance with the invention, a metallic honeycomb body, comprising an axial length, a partial volume covering at least 55% of the axial length, a radial dimension of at least 20 mm, an inflow end side and an outflow end side. Sheet-metal layers are structured to permit a fluid, in particular the exhaust gas from an internal combustion engine, to flow through the honeycomb body in a flow direction from the inflow end side to the outflow end side. The sheet-metal layers each have a surface area, partial regions and edges at the end sides. Each of the sheet-metal layers has a multiplicity of holes formed at least in the partial regions in the partial volume. Each of the holes has a hole surface area of between 1 and 120 mm 2 . The sheet-metal layer surface area in the partial volume is reduced by 10 to 80%, preferably 35 to 60%, by the holes as compared to a sheet-metal layer without holes. The partial volume is disposed at a distance from each of the end sides, preventing the holes from touching and from cutting through the edges of the end sides of the sheet-metal layers. Tests have shown that a honeycomb body with holes according to the invention, due to the improved flow properties in its interior and the resultant improved mass transfer properties between flow and surface, has an effectiveness which is comparable to and under certain circumstances even superior to a honeycomb body without holes, even though less coating material is used. The holes are so large that firstly they are not closed up by coating material during coating and secondly they also do not become blocked by particles in a fluid which is to be purified. Therefore, these are not holes similar to those used in a filter for retaining particles, but rather openings through which a fluid that is to be purified, in particular an exhaust gas from an internal combustion engine, can flow freely. It is important for the end-side edges not to be eaten into by holes or parts of holes, and consequently the holes should be at a distance from the end sides, for manufacture and technology reasons and with a view to subsequent durability. In accordance with another feature of the invention, as has already been stated, the holes have more advantages than disadvantages, and consequently the partial volume provided with holes should amount to more than 60%, preferably more than 90%, of the total honeycomb body volume. This makes it possible to exploit the positive effect to its maximum extent. In accordance with a further feature of the invention, the holes each have a surface area of from 5 to 60 mm 2 , for mechanical and fluid dynamic reasons. With a size of this type, they are easy to produce, do not disrupt a coating process and bring about the above-mentioned advantages of improved mass transfer. Holes of this size allow good cross-mixing and also allow dissipation of heat from the interior of the honeycomb body outward, not only by thermal conduction but also by thermal radiation, which passes through the holes into regions laying further toward the outside. Of course, the larger the total area of the holes compared to the total area of the sheet-metal layers which remain, the stronger these effects become. For comparable applications, the prior art has almost exclusively described openings in the sheet-metal layers which have polygonal contours. From a mechanical point of view, this is not advantageous under high and fluctuating loads, since cracks can form starting from the corners of the holes. Consequently, in accordance with an added feature of the invention, it is preferable to use rounded contours of the holes, so that the boundary lines of the holes do not have any corners, in particular do not have any acute angles. The holes should particularly preferably be round, oval or elliptical, in which case it is recommended, in the case of shapes which are not round, not to exceed a maximum diameter to minimum diameter ratio of two. In accordance with an additional feature of the invention, the holes of this type cannot be produced in a material-saving manner, as is possible, for example, with expanded metal, but rather have to be produced by removal of the material from a full-area sheet-metal layer. However, the material, which is preferably removed by stamping or cutting, can be reused to produce new sheet-metal layers. In accordance with yet another feature of the invention, depending on the way in which the sheet-metal layer is produced, the holes may also be removed as early as during the production process, an option which is suitable in particular for materials produced by galvanoplastic measures. In the case of a production process in which first of all an inexpensive material is produced and the quality of this material is subsequently improved by coating, e.g. with aluminum and/or chromium, it is recommended to produce the holes before the material is improved with these further materials. A further advantage of the invention is that the heat capacity of a honeycomb body with holes is, of course, lower than the heat capacity of a honeycomb body without holes. On the other hand, this enables honeycomb bodies according to the invention to be produced from thicker sheet-metal layers without the heat capacity increasing as compared to honeycomb bodies made from unperforated, thinner sheet-metal layers. In accordance with yet a further feature of the invention, the thickness of the sheet-metal layers may be between 20 and 80 μm, but a thickness of from 40 to 60 μm is preferred. The preferred range leads to improved mechanical stability, in particular at the end sides of a honeycomb body, and makes it possible to use tried-and-tested production processes which can no longer readily be applied to very thin foils. Nevertheless, the heat capacity of the honeycomb bodies which form is less than or equal to that of honeycomb bodies made from thinner foils without holes. In accordance with yet an added feature of the invention, in order to ensure mechanical stability of a honeycomb body according to the invention, the holes should have a minimum spacing of 0.5 mm, with the distances between the holes preferably in each case being approximately equal, so that no mechanical weak points are formed. Foils configured in this way can be corrugated without problems and then used in the remaining working steps for production of helical or coated and wrapped honeycomb bodies. In accordance with yet an additional feature of the invention, the honeycomb body according to the invention, like most which are known in the prior art, particularly preferably includes alternately disposed smooth and corrugated sheet-metal layers or includes alternating differently corrugated sheet-metal layers. Structures of this type produce the typical flow passages in a honeycomb body. Due to the positive effects of the holes, for the catalytic converters which are subsequently produced from the honeycomb bodies to have good conversion properties, it is not necessary for honeycomb bodies according to the invention to have an extremely high cell density. In accordance with again another feature of the invention, cell densities of between 200 and 1000 cpsi (cells per square inch), in particular cell densities of from 400 to 800 cpsi, are preferred. The inventive use of holes in the sheet-metal layers does not adversely affect the usability of the sheet-metal layers for most previously disclosed additional structures for influencing flow as have been mentioned in the description of the prior art. In particular, in accordance with again a further feature of the invention, the perforated sheet-metal layers can also be provided with transverse structures, with projections and/or with flow-guiding surfaces. In general, the holes even assist the action of structures of this type, since any pressure differences which occur in the passages can be compensated for by the openings, additional turbulence is generated and the flow profile within the honeycomb body is made more uniform. In accordance with again an added feature of the invention, the configuration of a honeycomb body according to the invention has particularly positive effects when a sensor, in particular a lambda sensor, which has been introduced into a cavity in a honeycomb body is used as proposed in the prior art. Since a measurement sensor, in particular an oxygen measurement sensor, is intended to measure a value for the fluid flowing in the honeycomb body which is as representative as possible, cross-mixing upstream of the sensor is highly advantageous. Therefore, honeycomb bodies according to the invention are particularly suitable for applications in which a lambda sensor is to be introduced into a cavity in the honeycomb body. In manufacturing technology terms, this requires a certain level of outlay in production of the sheet-metal layers, so that after assembly they subsequently form a suitable cavity. However, nowadays this outlay is manageable by using NC (numerically controlled) manufacturing installations. This at the same time makes it possible not to position any holes close to the edges of the sheet-metal layers which delimit the cavity, in order to prevent the edges from being attacked at this location too. Therefore, in accordance with again an additional feature of the invention, it is particularly preferable for there to be no holes in a region of from 1 to 5mm around the cavity for a measurement sensor. In accordance with still another feature of the invention, it is advantageous for the durability of a honeycomb body if the individual sheet-metal layers are connected to one another by joining, preferably by brazing, which typically takes place at the end sides of a honeycomb body. This is also a reason why no holes should intersect the end-side edge regions of the sheet-metal layers. On the other hand, the holes can also very deliberately prevent adhesive which has been applied to the end sides or brazing material which has been applied to the end sides from penetrating into the interior of the honeycomb body along the contact lines between the sheet-metal layers, which is often undesirable for mechanical reasons. In this case, holes end the capillary effect, so that the distance between the holes and the end sides of a honeycomb body can also be used very deliberately to limit a region which is connected by brazing. In accordance with another feature of the invention, a similar statement also applies to the attachment of the sheet-metal layers to a tubular casing. In this case too, due to the very stable connection to the tubular casing which is desired, it is more favorable if the edge regions are not intersected by holes. Furthermore, in this case too, the holes ensure that the brazing material cannot penetrate too far into the interior of the honeycomb body through the use of capillary action, but rather remains precisely where it is used to secure the sheet-metal layers. The size of the honeycomb body volume in catalytic converters (the sum of the volumes of the sheet-metal layers as well as the passages, openings, holes, etc. which are formed or enclosed) is dependent, for example, on the positioning in the exhaust section: if it is disposed in the engine compartment or in the immediate vicinity of the engine (within a distance of up to 0.5 m), this size is usually less than the capacity of the engine, e.g. less than 50% of the capacity, in particular less than 1 liter or 0.5 liters. If it is disposed in the underbody of a passenger car, the honeycomb body volume may also be greater than the capacity of the engine, preferably between 1 and 5 liters. Different sizes may also result in other applications such as, for example, for use in trucks, motorcycles, lawnmowers, hand-held appliances (hedge clippers, power saws, etc.) or the like, in which case the corresponding person skilled in the art can make suitable modifications. A similar statement is true for honeycomb bodies which are used as heat exchangers, flow mixers, adsorbers, particle traps, particulate filters and electrical heaters in exhaust systems. In these cases too, the person skilled in the art is aware of a range of tests which allow the honeycomb body volume to be suitably adapted. When constructing or configuring the pattern of holes in the sheet-metal layer, the desired application of the honeycomb bodies should also be taken into account. Since in this context it has not been possible to make use of knowledge gained from experience, tests have shown that the effects of the mixing or catalytic conversion combined, at the same time, with a considerably reduced deployment of catalytic material, were surprisingly good in sheet-metal foils with holes having a maximum extent which was greater than the structure width of the corrugation, in particular with holes in which even the shortest distance between opposite contours of the holes was still greater than the structure width. This preferably applies to the holes in the at least partially structured sheet-metal layers, so that the holes are superimposed on the corrugation or structure. In accordance with a further feature of the invention, it is particularly advantageous for all of the holes in the at least one partial volume to have an extent which is greater than the structure width. In accordance with an added feature of the invention, surprisingly good results can be achieved with a honeycomb body having sheet-metal foils in which the size of the hole is at least twice, preferably four times, in particular six times, as great as the structure width. In accordance with an added feature of the invention, at least some of the holes are constructed as slots having a maximum extent in each case which extends in the direction of a dedicated main axis. The holes constructed as slots are disposed in such a way that the honeycomb body has zones of different rigidities. In this context, a slot is understood as meaning in particular a hole which has two opposite rounded, preferably semicircle-like tip regions, the maxima or turning points of which define the main axis. The slot preferably has edges which run parallel to one another between these tip regions. The maximum extent in the direction of the main axis is preferably greater by at least a factor of two than the extent perpendicular to the main axis. The result of this is that webs are formed between adjacent slots. In this context, it is now proposed for these slots to be oriented in such a way with respect to the direction of the circumference, the radius, the center axis of the honeycomb body or of the sheet-metal layer or at least two of these directions in such a way that the rigidity of the honeycomb body differs in a plurality of zones. In this context, the term rigidity is to be understood as meaning the extent to which the zones yield to external forces in at least one of the above-mentioned directions. This means, for example, that in a first (in particular gas entry side) and if appropriate also in a third (in particular gas exit side) zone, the slots are disposed in such a way that the honeycomb body has a very low rigidity, while in a second (in particular inner) zone the honeycomb body is constructed to be relatively rigid. By way of example, if the thermal expansion characteristics of honeycomb bodies of this type in the exhaust system of an automobile are considered, it is established that the end sides expand and contract to a considerably greater extent due to the fluctuating thermal loads than central regions of the honeycomb body. The different zones make it possible to compensate for or interrupt differential thermal expansions of this type or different levels of forces introduced (e.g. as a result of pulses in the exhaust gas flow). In accordance with a concomitant feature of the invention, in this context, it is preferable for the holes which are constructed as slots to be at least partially offset with respect to one another in the direction of a circumference and/or a radius and/or a center axis and/or to be disposed at an angle in terms of their main axes. This means, for example, that: the holes are disposed in lines or rows parallel to the edge region, and that the lines or rows (or groups of adjacent lines or rows) which are adjacent in the direction parallel to the attachment region are offset with respect to one another in the direction of the edge region (with an identical or variable spacing between one another); the holes are disposed in lines or rows parallel to the attachment region, and that the lines or rows (or groups of adjacent lines or rows) which adjoin one another in the direction parallel to the edge region are offset with respect to one another in the direction of the attachment region (with an identical or variable distance between one another); the holes are oriented obliquely with respect to one another, in particular with main axes which are not at a right angle with respect to the orientation of the edge or attachment regions; at least in partial regions of the zones, the holes form a type of latticework; the holes generate different thicknesses of webs and/or different orientations of the webs with respect to the honeycomb body; or the holes are disposed in accordance with partial combinations as mentioned herein, in order to produce differing rigidities of the honeycomb body over its axial extent and/or its radius and/or its circumference. Other features which are considered as characteristic for the invention are set forth in the appended claims. Although the invention is illustrated and described herein as embodied in a metallic honeycomb body having at least partially perforated sheet-metal layers, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary, diagrammatic, plan view of a sheet-metal layer for the production of a honeycomb body according to the invention; FIG. 2 is a partly broken-away and sectional perspective view of a honeycomb body according to the invention; FIG. 3 is a partly broken-away and sectional side-elevational view of a catalytic converter having a honeycomb body according to the invention and a cavity for a lambda sensor; FIG. 4 is a perspective view of a corrugated sheet-metal layer with holes; FIG. 5 includes a series of views illustrating a sequence of a process for producing a honeycomb body according to the invention; FIG. 6 is a plan view of a configuration of a sheet-metal layer with slots; and FIG. 7 is a perspective view of a honeycomb body with a plurality of zones of different rigidity. DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the figures of the drawings in detail and first, particularly, to FIG. 1 thereof, there is seen a sheet-metal layer 1 , which may be either smooth or corrugated. Such a sheet-metal layer 1 is used to construct a honeycomb body 15 according to the invention, as is seen in FIG. 2 . This sheet-metal layer 1 has a width L which subsequently determines an axial length L of the honeycomb body 15 produced therefrom, as is seen in FIG. 3 . The size of the sheet-metal layer 1 in the other direction is dependent on the type of construction of the honeycomb body 15 which is to be produced. The size in the other direction may be very long if a helically wound honeycomb body 15 is to be produced therefrom or relatively short if it forms part of a stack of a plurality of sheet-metal layers 1 of this type which is subsequently wrapped to form a honeycomb body 15 . The sheet-metal layer 1 has a thickness 26 , shown in FIG. 4 , which may be between 20 and 80 μm, preferably between 40 and 60 μm. In a partial region (in this case illustrated as a section 29 ), the sheet-metal layer 1 has a large number of holes 6 , each of which has a hole surface area 23 of between 1 and 120 mm 2 , as is shown in FIG. 4 The holes 6 preferably have a diameter of between 3 and 8 mm and preferably between 4 and 6 mm. At least in regions, these holes 6 are disposed in a regular pattern and are preferably at identical distances D 7 from one another. However, it is also possible to vary the pattern from an inflow end side 12 to an outflow end side 13 , in which case, by way of example, the number of holes, the diameter of the holes and/or the distances D 7 are increased. This increase may take place continuously or in steps. It is also advantageous, after these values have been increased in a central region, for them to be reduced again toward the outflow end side 13 for certain applications. It is preferable for the holes 6 to be round or elliptical or oval with a maximum diameter R 6 of up to 8 mm. The distances D 7 between the holes 6 are selected in such a way that a sheet-metal layer surface area 24 , indicated in FIG. 5 , is reduced by from 10 to 80%, preferably 30 to 60%, as compared to an unperforated surface. The sheet-metal layer 1 has an inflow-side edge region 2 which is free of holes 6 . It is preferable for an outflow-side edge region 3 likewise to be free of holes 6 . This simplifies processing of the sheet-metal layer 1 , makes it possible to connect sheet-metal layers to one another in this edge region and prevents irregularly shaped (jagged) inflow end sides 12 or outflow end sides 13 from being formed during construction of a honeycomb body 15 . The inflow-side edge region has a width R 2 of from 1 to 5 mm, and the outflow-side edge region 3 has a width R 3 of from 1 to 5 mm. Moreover, the sheet-metal layer 1 has at least one first attachment region 4 , through the use of which the sheet-metal layer 1 can be subsequently secured to a tubular casing 14 shown in FIGS. 2 and 3 . This attachment region 4 , having a width R 4 , is preferably also free of holes 6 . A second attachment region 5 with a width R 5 is also free of holes 6 for configurations of honeycomb bodies 15 in which the sheet-metal layers 1 are secured to a tubular casing 14 at both ends. If the sheet-metal layer 1 is to be used to produce a honeycomb body 15 which has a cavity 7 for accommodating a measurement sensor 9 shown in FIG. 3 , a corresponding cavity 7 is to be provided in the sheet-metal layer 1 . According to the invention, this cavity is surrounded by a hole-free edge 8 , which is once again used to make the sheet-metal layer 1 easier to process and to facilitate production of a uniform cavity 7 . A flow direction S of a fluid which can subsequently flow through the honeycomb body 15 is indicated by arrows in the figures. A path length B of the hole-free edge 8 is preferably at least 1 mm over the entire circumference of the cavity. FIG. 2 shows a perspective view of a honeycomb body 15 according to the invention in which a dimension 22 of a perforated partial volume T is diagrammatically indicated. In this case, the dimension 22 starts from the center of the cross section of the honeycomb body, but it is also possible for the partial volume T to be formed as a type of inner, annular hollow cylinder in which the dimension 22 forms any desired part of the diameter or radius of the cross section. The honeycomb body 15 , which is shown by way of example, is wound helically from a smooth sheet-metal layer 10 and a corrugated sheet-metal layer 11 , which are connected to a tubular casing 14 in an attachment region 4 . FIG. 3 diagrammatically depicts a partially cut-away side view of a catalytic converter 28 with a cavity 7 for receiving a lambda sensor 9 . An exhaust gas can flow through the catalytic converter 28 in the flow direction S starting from the inflow end side 12 and leading to the outflow end side 13 . There is a hole-free edge region 2 at the inflow end side 12 and a hole-free edge region 3 at the outflow end side 13 . The perforated partial volume T is disposed between these edge regions and therefore extends over virtually the entire axial length L of the honeycomb body 15 . The cavity 7 in the honeycomb body 15 was produced either after the honeycomb body 15 had been completed or before it had been completed by suitable positioning of cavities 7 in the individual sheet-metal layers 10 , 11 . The measurement sensor 9 , in particular an oxygen measurement sensor 9 , can be introduced into this cavity 7 . In order to ensure uniform edges of the cavity 7 , the hole-free edge 8 , in which the sheet-metal layers 10 , 11 do not have any holes 6 , surrounds the cavity 7 . The combination of a honeycomb body 15 with holes 6 and a cavity 7 for a measurement sensor 9 which is illustrated herein is particularly advantageous because the holes 6 upstream of the measurement sensor 9 allow cross-mixing in the honeycomb body 15 and consequently the measurement sensor 9 can measure a representative measured value for the composition of the fluid in the honeycomb body 15 as a whole. FIG. 4 shows a diagrammatic and perspective illustration of a corrugated sheet-metal layer 1 with holes 6 . The corrugations or structure of the sheet-metal layer 1 can be described, for example, by a structure height H and a structure width A, as seen in FIGS. 4 and 5 . The above-mentioned advantages, in particular with regard to the cross-mixing of the exhaust-gas stream and the inexpensive production of a honeycomb body 15 of this type, can be achieved particularly successfully if the maximum extent R 6 of a hole 6 is greater than the structure width A. In the illustrated exemplary embodiment, the holes 6 have an extent or diameter R 6 which corresponds to approximately three times the structure width A of the sinusoidal corrugation of the sheet-metal layer 1 . In this case, the holes 6 are disposed in such a way that there is a regular pattern in which each corrugation peak or corrugation valley is interrupted at least by one hole 6 over the axial length within the section 29 which is delimited by the unperforated edges R 3 , R 2 , R 5 (and the non-illustrated edge R 4 ) of the sheet-metal layer 1 and forms the partial volume T in the honeycomb body 15 . With regard to the proportion of the sheet-metal layer surface area 24 which is taken up by the holes 6 , it should be noted that in particular the sheet-metal layer surface area 24 within the section 29 is reduced by 30–60%, and preferably the overall sheet-metal layer surface area 24 (i.e. including the edges) is reduced by 20–40%. In order to achieve the maximum possible amount of perforation in the section 29 , it is advantageous, as illustrated in FIG. 4 , for the distances D 7 between the holes to be selected to be no greater than a few structure widths A, in particular less than 5 structure widths A and preferably less than 3 structure widths A, of the sheet-metal layer 1 . For stability reasons, for particular applications of the honeycomb body 15 , it is also possible under certain circumstances for the distances D 7 in different directions (e.g. in the longitudinal and transverse directions) to be constructed to differ from one another in terms of their size, in which case it is preferable for a uniform distance D 7 between the holes 6 to be maintained in one direction. Moreover, in the vicinity of the edge R 2 , FIG. 4 shows a microstructure 27 , the height of which is considerably less than the structure height H. The microstructure 27 is used, for example, to delimit the attachment region, since in this way a small gap is formed between the sheet-metal layers 1 disposed adjacent one another. During a brazing process, this gap prevents liquid brazing material from accumulating in the section 29 as a result of capillary effects, where it may produce undesirable connections. FIG. 5 diagrammatically depicts a possible particularly suitable process for producing a catalytic converter. In a first step 1 , the holes 6 are introduced into the sheet-metal layer 1 . In this case, step 1 is carried out mechanically through the use of a stamping device 16 . In the next step 2 , the structures are produced in the perforated sheet-metal layer 1 through the use of two meshing profiling tools 17 , so that corrugated sheet-metal layers 11 with a structure height H and a structure width A are formed. These corrugated, at least partially perforated sheet-metal layers 11 are then stacked with smooth sheet-metal layers 10 (perforated or unperforated) to form a honeycomb body 15 in a step 3 . These sheet-metal layers 10 , 11 are then wound together and introduced into a tubular casing 14 in a step 4 . After the sheet-metal layers 10 , 11 have been stacked and/or wound, the way in which the holes 6 in the adjacent sheet-metal layers 10 , 11 are disposed with respect to one another may be of importance. In principle, it is possible for the holes to be oriented with respect to one another in such a way that they (almost completely) overlap one another. This may be advantageous, for example, if high levels of pressure losses (as may occur with a very turbulent flow) are to be avoided. On the other hand, if the flow is substantially uniform when it enters the honeycomb body 15 , it is advantageous for the maximum possible number of inflow edges which lead to swirling to be provided in the interior of the honeycomb body 15 . It is therefore expedient in the latter case for the holes 6 in the adjacent sheet-metal layers 10 , 11 to be offset with respect to one another. In addition to the possible variations with regard to the relative position of the holes 6 with respect to one another, it is also advantageous to consider using different forms of holes 6 even when the holes 6 are superimposed or overlap. For example, different distances D 7 between the holes, different maximum extents R 6 or different contours 25 of the holes 6 themselves as seen in FIG. 4 , as well as their relative position with respect to one another in the sheet-metal layers 10 , 11 disposed adjacent one another can be combined with one another. After a brazing process in which, in particular, the unperforated regions or edges R 1 , R 2 , R 3 , R 4 are provided with non-illustrated brazing material, the sheet-metal layers are subjected to a heat treatment with one another and also with the tubular casing 14 in a furnace 18 in a step 5 . In particular, they are subjected to high-temperature brazing in vacuo and/or under a shielding gas atmosphere. A support body 19 produced in this way can then also be provided with a catalytically active coating 20 in order to enable it to be ultimately used as a catalytic converter in the exhaust system of a motor vehicle. The support body 19 is coated with what is known as a washcoat, which has a very rugged surface. This rugged surface firstly ensures that sufficient space is available for fixing a catalyst (e.g. platinum, rhodium, etc.) and secondly is used to swirl up the exhaust gas flowing through, producing particularly intensive contact with the catalyst. The washcoat usually is formed of a mixture of an aluminum oxide from the transition series and at least one promoter oxide such as, for example, rare earth oxides, zirconium oxide, nickel oxide, iron oxide, germanium oxide and barium oxide. The washcoat layer having a large surface area which promotes catalysis is applied in a known way by immersing the honeycomb body 15 or the support body 19 in or spraying it with, a liquid washcoat dispersion. However, particularly in the case of the perforated sheet-metal layers 11 , there is a risk of the washcoat dispersion covering and closing up the holes 6 . This would lead to the level of perforation in the partial volume T of the honeycomb body 15 being lower than desired, with the result that firstly the cross-mixing between the exhaust-gas partial streams which are formed as a result of the exhaust gas coming into contact with the honeycomb-like form of the end side 12 of the honeycomb body 15 being reduced and secondly too much washcoat dispersion being required. For this reason, the coating operation is carried out in a step 6 by using a vibratory installation 21 , which generates relative motion between the washcoat dispersion and the support body 19 . This relative motion includes, in particular, continuous and/or discontinuous vibration, pulsed excitation (e.g. similar to a hammer blow) or similar stimulation of the support body 19 , which may also be combined with one another in any desired sequence and/or in different directions. If the washcoat dispersion is to be excited directly, a frequency in the ultrasound range, for example, has proven particularly advantageous. The excitation took place in a frequency range from 20 kHz to 10 MHz. In particular, in the case of indirect excitation, i.e. for example, brought about by vibration of the support body 19 , frequencies in the audible range have proven appropriate, in which case in particular excitation at a frequency of between 20 Hz and 15 kHz has ensured a drop in the viscosity of the washcoat dispersion over a very prolonged period. The result of this is that a uniform distribution of the dispersion is ensured. Furthermore, it has proven particularly advantageous for the support body 19 to be excited one final time in a pulse-like manner, in particular after it has emerged from the coating bath, in order to ensure that there are no longer any holes 6 covered over by the washcoat dispersion. After the excess washcoat dispersion has been removed, the washcoat is dried in the honeycomb body and finally calcined at temperatures which are generally above 450° C. During the calcining, the volatile constituents of the washcoat dispersion are forced out, so that a temperature-resistant, catalysis-promoting layer with a high specific surface area is produced. If appropriate, this operation may be repeated a number of times in order to achieve a desired layer thickness. FIG. 6 diagrammatically depicts a configuration of a sheet-metal layer 1 with holes 6 which are formed as slots. This figure illustrates the sheet-metal layer 1 including its attachment regions 4 , 5 and its edge regions 2 , 3 . In this context, it should be noted that the holes 6 do not have to extend over the entire length and/or width of the sheet-metal layer 1 . The sheet-metal layer 1 is diagrammatically divided into four sectors (denoted by numerals I, II, III and IV). The holes 6 which are constructed as slots and the maximum extent R 6 of which in each case extends in the direction of a dedicated main axis 30 are disposed differently with respect to one another in the sectors. The holes 6 which are constructed as slots are at least in some cases offset with respect to one another in the direction of a circumference 37 and/or a radius 36 and/or a center axis 35 seen in FIG. 7 and/or are disposed at an angle 31 seen in FIG. 6 in terms of their main axes 30 . In the first sector I, the main axes 30 of the holes 6 have the same orientation, and accordingly they are parallel to one another. The illustrated lines or rows of holes 6 may be repeated constantly within a zone 32 , 33 , 34 seen in FIG. 7 , but it is also possible for the lines or rows to be disposed obliquely with respect to one another and/or for the holes 6 in the lines or rows to be offset with respect to one another. In the second sector II, the slots are illustrated with a different orientation from those in the first sector I, in such a way that the lines or rows within the second sector are offset with respect to one another. In the third sector III, it can be seen that combinations of the configurations of these slots described above are also possible. The fourth sector IV illustrates a relatively rigid configuration of the slots, that is a latticework. The main axes 30 of the adjacent holes 6 are at an angle 31 with respect to one another. This angle preferably lies in a range of from 30° to 60 20 . A latticework of this type can also be formed by the holes 6 which are constructed as slots being oriented in lines or rows and, in terms of their main axes 30 , obliquely with respect to the edge regions 2 , 3 . In that case all of the slots within the line or row have the same orientation, while the adjacent lines or rows running parallel are disposed offset, with the slots at a different angle with respect to the edge regions 2 , 3 . It is preferable for the slots of the adjacent lines or rows to be disposed in such a way that the main axes of the holes 6 in a first line are oriented perpendicular with respect to the main axes of the slots disposed in the adjacent lines or rows and/or the main axes of the slots in the first line or row intersect the center of the slots of the adjacent lines or rows. The configuration of the holes 6 means that the sheet-metal layer 1 reacts to external forces with different levels of sensitivity in the sectors. In the first sector, it is relatively rigid with respect to forces from the direction of the attachment regions 5 , 4 but more elastic with regard to forces perpendicular thereto. The exact opposite is true of sector II. Accordingly, the rigidity characteristics of the honeycomb body 15 can be set in a zoned manner in the zones 32 , 33 , 34 according to the orientation of the holes 6 . The zones 32 , 33 , 34 can divide the honeycomb body in the direction of the axial length L, the circumference 37 or the radius 36 . Although FIG. 7 shows only three zones, under certain circumstances it is also possible to provide two or more zones. The present invention allows a high coating effectiveness for the treatment of a fluid to be achieved in most known forms of honeycomb bodies, with a reduced usage of coating material, while nevertheless enabling properties relating to mechanical stability, heat capacity, thermal conductivity and the like of a honeycomb body to be specifically matched to the requirements of individual applications.	A metallic honeycomb body has an axial length, a partial volume covering at least 55% of the axial length, a radial dimension of at least 20 mm, an inflow end side and an outflow end side. The honeycomb body includes sheet-metal layers structured to permit a fluid to flow through the honeycomb body in a flow direction from the inflow end side to the outflow end side. The sheet-metal layers each have a surface area, partial regions and edges at the end sides. Each of the sheet-metal layers have a multiplicity of holes formed at least in the partial regions in the partial volume. Each of the holes have a hole surface area of between 1 and 120 mm 2 . The sheet-metal layer surface area in the partial volume is reduced by 10 to 80% by the holes as compared to a sheet-metal layer without holes. The partial volume is disposed at a distance from each of the end sides, preventing the holes from touching and from cutting through the edges of the end sides of the sheet-metal layers.	8
FIELD OF THE INVENTION [0001] The present invention generally relates to fuel processors and, more particularly, relates to a fuel processor system having gas recirculation for improved startup, shut down, turn down, and transient operation. BACKGROUND OF THE INVENTION [0002] As is well known to those skilled in the art, in order to heat rapidly the mass of a fuel processor to its proper operating temperature during a startup cycle, it is preferable to provide the largest possible heating gas flow therethrough. However, using fuel rich-combustion gas flow may exceed the temperature limits in the earlier stages of the fuel processor, thereby requiring additional stages to fully heat the remaining stages of the fuel processor. [0003] During a shut down cycle, it is desirable to remove water from the fuel processor so that the water does not condense onto the catalysts when the fuel processor completely cools, which may damage the catalysts. Furthermore, it is also desirable to stop the fuel processor in a pressurized state so that when the fuel processor cools and the gases contract, the pressure the fuel processor remains above atmospheric pressure so that air is not drawn into the fuel processor. Conventional shut down methods cannot continue operating without water injection, as the ATR catalyst would get too hot. [0004] During a turn down cycle, it is preferable to circulate a larger flow so that the residence times within the reactors are more constant. However, in conventional fuel processors, as the power level is turned down the flow is thus reduced and the residence times in each reactor increases. This increase in residence times may lead to auto-ignition in the inlet, reverse water gas shift in the PrOx, cell reversal in fuel cell stack due to non-uniform flow distribution of hydrogen containing reformate, and water collection in fuel cell stack. [0005] During a transient cycle, it is preferable to have a constant flow through the reactors such that the pressure in the reactors remains generally constant, thereby minimizing the lag in transient response associated with filling or venting volumes of the fuel processor. [0006] Accordingly, there exists a need in the relevant art to provide a fuel processor that is capable of rapid thermal start without the complexity of multiple stages or risk of oxygen exposure. Furthermore, there exists a need in the relevant art to provide a fuel processor that, during shut down, is capable of minimizing water in the reformate and be shut down at an elevated pressure to minimize condensation on the catalyst and air ingestion upon cooling. Still further, there exists a need in the relevant art to provide a fuel processor that, during turn down, is capable of minimizing auto-ignition in the inlet, reverse water gas shift in the PrOx, cell reversal in fuel cell stack due to non-uniform flow distribution of hydrogen containing reformate, and water collection in fuel cell stack. Yet further, there exists a need in the relevant art to provide a fuel processor that, during transient operation, is capable of maintaining a generally constant flow rate through to the fuel processor to minimize the lag time associated with filling or venting volumes of the fuel processor. Still further, there exists a need in the relevant art to provide a fuel processor that is capable of operating without water injection. SUMMARY OF THE INVENTION [0007] A fuel processor system capable of recirculating fuel processor system gases, such as reformate, anode exhaust, and/or combustor exhaust, through the fuel processor to provide a number of distinct advantages is provided. A fuel processor is also provided for converting a hydrogen-containing fuel to H 2 -containing reformate. The fuel processor system may also include a plurality of fuel cells discharging an H 2 -containing anode effluent and an O 2 -containing cathode effluent. A catalytic combustor is positioned in series downstream from the plurality of fuel cells and a vaporizer reactor is coupled to the catalytic combustor. A bypass passage interconnects an outlet of at least one of the group consisting of the fuel processor, the fuel cell, the catalytic combustor, and the vaporizer reactor to the inlet of the fuel processor. The bypass passage is operable to recirculate a fuel processor system gas to the inlet of the fuel processor. [0008] Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS [0009] The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: [0010] [0010]FIG. 1 is a schematic view illustrating a fuel processor system according to a first embodiment of the present invention; [0011] [0011]FIG. 2 is a schematic view illustrating a fuel processor system according to a second embodiment of the present invention; [0012] [0012]FIG. 3 is a schematic view illustrating a fuel processor system according to a third embodiment of the present invention; and [0013] [0013]FIG. 4 is a schematic view illustrating a fuel processor system according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0014] The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. For example, the present invention is hereafter described in the context of a fuel cell fueled by reformed gasoline. However, it is to be understood that the principles embodied herein are equally applicable to fuel cells fueled by other reformable fuels. Furthermore, the present invention hereafter described in the context of a self contained fuel cell system having a reforming system and a fuel cell system. However, it is to be understood that the principles embodied herein are equally applicable to a reforming system only. [0015] Referring to FIG. 1, a fuel processor system, generally indicated as 10 , according to a first embodiment of the present invention is illustrated, which provides rapid startup capabilities. Fuel processor system 10 generally includes a fuel processor 12 , a fuel cell stack 14 , a catalytic combustor reactor 16 , and a vaporizer reactor 18 . Fuel processor 12 would typically include a primary reactor 12 . 2 such as a steam reformer or an autothermal reformer, a water gas shift (WGS) reactor 12 . 4 and a preferential oxidation (PrOx) reactor 12 . 6 . [0016] Fuel processor system 10 is arranged such that a first fuel inlet stream 20 and a first water inlet stream 22 are introduced into fuel processor 12 to produce a reformate stream 24 according to conventional principles. During a startup cycle, an anode bypass valve 26 directs reformate stream 24 to an anode bypass passage 28 . It is necessary to initially bypass fuel cell stack 14 until “stack grade” (having CO content less than about 100 ppm) reformate is produced. In order to produce such stack grade reformate, it is necessary to heat the various components of fuel processor system 10 to their respective operating temperatures. Recirculated reformate in passage 30 from anode bypass passage 28 is drawn into a recirculation compressor 32 together with a first inlet air stream 34 . [0017] First fuel inlet stream 20 is then introduced into fuel processor 12 . Reactions may be initiated in fuel processor 12 via a spark lit burner or by an electrically heated catalyst section (not shown). Heat produced by the reaction of first fuel inlet stream 20 and first inlet air stream 34 warms fuel processor 12 . First fuel inlet stream 20 and first inlet air stream 34 are introduced in proportions slightly rich of stoichiometric. This ensures that there is no excess oxygen, which could damage the catalysts within fuel processor 12 . Ordinarily, reactions near stoichiometric conditions produce damagingly high temperatures; however, with a large excess of recirculated reformate 30 acting as a diluent, the gas temperature within fuel processor 12 is maintained at an appropriate level. [0018] A portion, generally indicated at 36 , of the flow through anode bypass passage 28 is exhausted to catalytic combustor reactor 16 . Under steady flow, this exhausted reformate 36 is equal to the total mass flow of first fuel inlet stream 20 , first inlet air stream 34 , first water inlet stream 22 and vaporizer steam 38 that passes through fuel processor 12 . This exhausted reformate 36 is reacted with a second inlet air stream 40 in catalytic combustor reactor 16 . Second inlet air stream 40 is directed to catalytic combustor reactor 16 via a stack air compressor 42 , a cathode bypass valve 44 , a cathode bypass passage 46 , and an exhaust passage 48 . Second inlet air stream 40 is bypassed around fuel cell stack 14 during startup to prevent drying of the membranes within fuel cell stack 14 . Heat from the reaction in catalytic combustor reactor 16 is integrated back into fuel processor 12 by vaporizing second water inlet stream 50 in vaporizer reactor 18 to produce vaporizer steam 38 , which typically is delivered to the PrOx-vaporizer or steam lines within fuel processor 12 . Exhaust gases from combustor 16 exits vaporizer reactor 18 through exhaust outlet 66 . [0019] During the startup cycle, the fuel and air are completely consumed (stoichiometric conditions) for maximum heat release within fuel processor system 12 for rapid heating without excessively high temperatures. However, it is important to note that the temperature within the PrOx 12 . 6 may initially be relatively high at about 357° C. However, once the PrOx is heated, normal operation is such that cooling of the PrOx according to conventional methods can be used. [0020] Referring again to FIG. 1, once the various reactors within fuel processor 12 are warmed to their operating temperature, anode bypass valve 26 routes reformate stream 24 to fuel cell stack 14 via passage 52 . Second inlet air stream 40 is then directed by cathode bypass valve 44 to the cathode side of fuel cell stack 14 via passage 54 . The hydrogen from reformate stream 24 reacts with the oxygen from second air inlet stream 40 across a membrane electrode assembly within fuel cell stack 14 to produce electricity. Anode exhaust or stack effluent 56 from the anode side of fuel cell stack 14 includes a portion of hydrogen that is directed back to catalytic combustor reactor 16 to provide heat recovered in vaporizer 18 . Cathode exhaust 58 from the cathode side of fuel cell stack 14 includes oxygen also for use in catalytic combustor reactor 16 . Anode exhaust 56 and cathode exhaust 58 are combined in exhaust passage 48 and react in catalytic combustor reactor 16 . Vaporizer reactor 18 continues to provide vaporizer steam 38 to fuel processor 12 . Note that the PrOx air, within fuel processor 12 , is drawn from recirculation compressor 32 which contains only first inlet air stream 34 when anode bypass valve 26 directs reformate stream 24 to fuel cell stack 14 . Preferably, a reformate check valve 60 is disposed in exhausted reformate passage 36 to ensure that anode exhaust 56 and cathode exhaust 58 in exhaust passage 48 are not drawn into fuel processor 12 by recirculation compressor 32 . [0021] As is well known in the art, catalysts, such as that which is often used in water gas shift reactors (i.e. CuZn), are often sensitive to oxygen and condensed water. Therefore, this is particularly important after shut down when the fuel processor cools and any water vapor condenses. That is, the reformate gases within fuel processors often have a very high water (steam) content (typically 30%), which condense when the fuel processor cools after shut down. Additionally, as the fuel processor cools the condensation of water and the cooling of gases within the fuel processor may cause a reduction in gas pressure sufficient to pull a vacuum even if valves at the inlet and exit seal a fuel processor. At this point, any leaks present in the various valves, fittings, or flanges may allow air into the fuel processor and potentially damage the water gas shift catalyst. Therefore, additional features are illustrated in FIG. 2 to address these shut down issues. [0022] The fuel processor system 10 ′, shown in FIG. 2, is the same as that described in reference to FIG. 1, where like reference numerals are used to indicate like components. Referring to FIG. 2, a recirculation valve 102 is positioned in recirculated reformate passage 30 and an exhaust valve 104 is positioned in exhaust reformate passage 36 . Recirculation valve 102 and exhaust valve 104 are used in conjunction to control the recirculation ratio (i.e., the ratio of recirculated reformate stream to the total reformate stream). That is, by opening recirculation valve 102 the flow of recirculated reformate 30 is increased, while opening exhaust valve 104 the flow of recirculated reformate 30 is decreased. Furthermore, opening both valves 102 , 104 decreases the pressure within fuel processor 12 . Recirculation valve 102 and/or exhaust valve 104 may be closed to prevent anode exhaust 56 and cathode exhaust 58 from being drawn into fuel processor 12 by recirculation compressor 32 . [0023] The transition to normal operation for fuel processor system 10 ′, shown in FIG. 2, is the same as described in reference to FIG. 1. [0024] Fuel processor system 10 ′, shown in FIG. 2, further provide a means to shut down fuel processor 12 without water condensation or air ingestion. For shut down, reformate stream 24 is circulated to anode bypass passage 28 via anode bypass valve 26 . Exhaust valve 104 remains closed to cause higher pressures within fuel processor 12 . Recirculation valve 102 is then slightly opened to maximize pressure within the capacity of recirculation compressor 32 . During shut down, water is condensed and separated from reformate stream 24 in a condenser 106 , which is connected to the system coolant loop (not shown). In normal operation, condenser 106 is used as an anode pre-cooler before fuel cell stack 14 . [0025] To further increase the pressure within fuel processor 12 during shut down, recirculation compressor 32 draws in first inlet air stream 34 . Preferably, the inlet to recirculation compressor 32 and the downstream side of circulation valve 102 are small in volume such that after recirculation compressor 32 is stopped, the pressure will remain high. Subsequently, the oxygen within first inlet air stream 34 will react with the hydrogen in recirculated reformate 30 within fuel processor 12 to produce additional heat, thereby increasing the pressure within fuel processor 12 . However, if necessary, additional fuel from first fuel inlet stream 20 may be added during shut down to consume the oxygen in first inlet air stream 34 in order to provide sufficient reactants (H 2 and CO) within fuel processor 12 . An oxygen sensor 108 is used in the fuel processor 12 as feedback to ensure that excess oxygen is not present. If the pressure within fuel processor 12 is higher than a predetermined level, exhaust valve 104 may be opened to reduce such pressure. [0026] Once the water has been condensed from reformate stream 24 and a high pressure condition has been achieved within fuel processor 12 , fuel processor air mass flow controller 62 is closed to seal the inlet, anode bypass valve 26 remains in the bypass position, and exhaust valve 104 remains closed to seal the exit. Recirculation compressor 32 is then stopped. The resident gases within fuel processor 12 are dry and at an elevated pressure, which is desired for shut down condition, particularly with a CuZn water gas shift catalyst. [0027] During the shut down cycle, the fuel and air are completely consumed (stoichiometric conditions) without water injection and without excessively high reactor temperatures to allow the gases to be dried by condenser 106 . [0028] As is well known in the art, conventional fuel processors suffer from various disadvantages when operating at reduce power and reduced flow, such as auto-ignition in the inlet, reverse water gas shift in the PrOx, cell reversal in the fuel cell stack, and water collection in the fuel cell stack. Furthermore, the transition between power levels are often slow to react due to the time necessary to pressurize or vent reactor volumes so as to achieve steady flow conditions at the new power level. [0029] Within the primary reactor temperatures in the inlet region increase such that there is a limited amount of time before undesirable auto-ignition of the fuel will occur. As the flow through the fuel processor is reduced at low power, the residence time within the inlet is increased. Thus, the rate of reduction in flow and power is limited by the auto-ignition condition in the inlet. [0030] Within the PrOx reactor, after the oxygen is consumed, reformate that is exposed to catalyst will undergo reverse water gas shift reactions, thereby consuming desirable H 2 and creating undesirable CO. At reduced flow, the oxygen is consumed earlier in the PrOx reactor, thereby leaving a larger section of catalyst and a longer residence time for reverse water gas shift reactions to occur. [0031] Within the fuel cell stack, the current flow through each fuel cell is limited by the fuel cell provided the lowest quantity of H 2 . That is, the fuel cell with the lowest H 2 flow limits the current through all of the remaining fuel cells. Therefore, a portion of the available quantity of H 2 (typically 10 to 20%) leaves the fuel cell stack unused. At reduced flows, the portion of H 2 leaving the fuel cell stack needs to be higher for stable operation, which is likely the result of less uniform flow distribution at reduced flows. Also contributing to the minimum flow for stable fuel cell stack operation is the need to clear condensed water to prevent it from collecting in and blocking passages within the gas distribution plates. [0032] In conventional systems, the flow rate through the fuel processor system varies with power level, thus the associated pressure drop necessitates a change in reactor pressure between power levels. However, a change in reactor pressure requires time for flow to fill or vent to the downstream reactors in order to achieve the steady pressure at the new power level. The numerous aforementioned disadvantages are overcome in the present invention by maintaining a higher flow rate, even during low power operation, by recirculating gases through the fuel processor and stack. [0033] Fuel processor system 10 ″, shown in FIG. 3, illustrates a system having reformate circulation through the fuel processor for startup, means for water condensation and pressurization for shut down, and circulation through the fuel processor and anode for turn down and transients. The fuel processor system 10 ″, shown in FIG. 3, is the same as that described in reference to FIGS. 1 and 2, where like reference numerals are used to indicate like components. [0034] More particularly, for startup, anode bypass valve 26 directs reformate stream 24 to anode bypass passage 28 . First fuel inlet stream 20 is introduced into fuel processor 12 . First inlet air stream 34 is delivered to fuel processor 12 by a fuel processor air compressor 202 . FIG. 3 shows first inlet air stream 34 being delivered to three locations in fuel processor 12 in the form of POx air stream 204 , start air stream 206 and PrOx air stream 208 . POx and PrOx air streams 204 , 208 would normally be part of fuel processor 12 . Heat produced by the reactions of fuel inlet stream 20 and inlet air stream 34 warms fuel processor 12 . By staging the inlet air to provide multiple heating locations, the startup time is reduced by improving heat distribution within fuel processor 12 . [0035] To initiate reactions in each of these locations, a spark lit burner or an electrically heated catalyst section (not shown) is used. The overall oxygen to carbon (o/c) ratio (i.e. ratio of first inlet air stream 34 to first fuel inlet stream 20 ) is introduced in proportions slightly rich of stoichiometric to ensure that no excess oxygen is present, which could damage the catalyst within fuel processor 12 . The recirculated reformate 30 acts as a diluent so that all the available first inlet air stream 34 is reacted without excessively high temperatures within fuel processor 12 . [0036] Exhaust reformate passage 36 is employed to exhaust excess reformate to catalytic combustor reactor 16 . Under steady flow, this exhausted reformate in passage 36 is equal to the total mass flow of first fuel inlet stream 20 , first inlet air stream 34 , first water inlet stream 22 and vaporizer steam 38 that passes through fuel processor 12 . This exhausted reformate in passage 36 is reacted with second inlet air stream 40 in catalytic combustor reactor 16 . Second inlet air stream 40 is directed to catalytic combustor reactor 16 via stack air compressor 42 , cathode bypass valve 44 , cathode bypass passage 46 , and exhaust passage 48 . Second inlet air stream 40 is bypassed around fuel cell stack 14 during startup to prevent drying of the membranes within fuel cell stack 14 . Heat from the reaction in catalytic combustor reactor 16 is integrated back into fuel processor 12 by vaporizing second water inlet stream 50 in vaporizer reactor 18 to produce vaporizer steam 38 , which typically is delivered to the PrOx-vaporizer or steam lines within fuel processor 12 . An anode check valve 210 and a cathode check valve 212 are shown to prevent back flow of reformate exhaust 48 into fuel cell stack 14 . Preferably, a reformate check valve 60 is also disposed in exhausted reformate passage 36 to ensure that anode exhaust 56 and cathode exhaust 58 in exhaust passage 48 are not drawn into fuel processor 12 by recirculation compressor 32 . [0037] Once the various reactors within fuel processor 12 are warmed to their operating temperature, anode bypass valve 26 routes reformate stream 24 to fuel cell stack 14 via anode inlet passage 52 . Second inlet air stream 40 is then directed by cathode bypass valve 44 to the cathode side of fuel cell stack 14 via cathode inlet passage 54 . The hydrogen from reformate stream 24 reacts with the oxygen from second air inlet stream 40 across a membrane electrode assembly within fuel cell stack 14 to produce electricity. Anode exhaust or stack effluent 56 from the anode side of fuel cell stack 14 includes a portion of hydrogen that is directed back to catalytic combustor reactor 16 where it is oxidized to provide heat. Cathode exhaust 58 from the cathode side of fuel cell stack 14 includes oxygen which may also be used in catalytic combustor reactor 16 . Anode exhaust 56 and cathode exhaust 58 are combined in exhaust passage 48 and react in catalytic combustor reactor 16 . Vaporizer reactor 18 continues to provide vaporizer steam 38 to fuel processor 12 . [0038] A back pressure regulator 214 is used to set the pressure within fuel processor system 10 ″, while recirculation compressor 32 determines the amount of reformate recirculated. As additional flow from first fuel inlet stream 20 , first inlet air stream 34 , first water inlet stream 22 , and vaporizer steam 38 is added to fuel processor 12 , additional reformate flow will split to exhausted reformate passage 36 to maintain the system pressure. Therefore, at high power, the system 10 ″ operates at a low recirculation ratio, whereby a larger portion of reformate stream 24 is “fresh” having a relatively high H 2 content. At low power, the system 10 ″ operates at a high recirculation ratio, whereby a larger portion of reformate stream 24 is re-circulated and having a relatively low H 2 content. It is important to note that recirculation compressor 32 according to the present embodiment need only overcome the pressure drop through fuel processor 12 and fuel cell stack 14 during normal operation, unlike the system shown in FIG. 2 where the pressure would drop to atmospheric pressure downstream of recirculation valve 102 to allow first inlet air stream 34 to be drawn in. To this end, fuel processor system 10 ″ illustrated in FIG. 3 requires an additional fuel processor air compressor 202 . Alternatively, stack air compressor 42 can be used to deliver air to fuel processor 12 . [0039] As best seen in FIG. 3, fuel processor system 10 ″ maintains a flow rate that is approximately equal to a fuel processor system operating at an optimum power level. This higher flow rate helps overcome many of the disadvantages described above. [0040] During the shut down cycle of fuel processor system 10 ″, anode bypass valve 26 routes reformate stream 24 to anode bypass passage 28 . Second inlet air stream 40 is then directed by cathode bypass valve 44 through cathode bypass passage 46 to catalytic combustor reactor 16 . This will provide air to catalytic combustor reactor 16 to react with any exhausted reformate in passage 36 from the recirculation loop. [0041] Backpressure regulator 214 is adjusted to indirectly produce the highest possible pressure within the capacity of recirculation compressor 32 . As reformate stream 24 recirculates through fuel processor 12 , water is condensed and separated in condenser 106 . [0042] To further increase the pressure within fuel processor 12 prior to shut down, fuel processor air compressor 202 draws in first inlet air stream 34 . Subsequently, the oxygen within first inlet air stream 34 will react with the hydrogen in circulated reformate 30 within fuel processor 12 to produce additional heat, thereby increasing the pressure within fuel processor 12 . However, if necessary, additional fuel from first fuel inlet stream 20 may be added during shut down to consume the oxygen in first inlet air stream 34 in order to provide sufficient reactants (H 2 and CO) within fuel processor 12 . An O 2 sensor 108 is used in fuel processor 12 as feedback to ensure that excess oxygen is not present. [0043] Once the water has been condensed from reformate stream 24 and a high pressure condition has been achieved within fuel processor 12 , fuel processor air mass flow controllers 216 , 218 , 220 and stack air mass flow controller 64 are closed to seal the inlets, anode bypass valve 26 and cathode bypass valve 44 remain in the bypass position, and back pressure regulator 214 remains closed to seal the exit. Recirculation compressor 32 , fuel processor air compressor 202 , and stack air compressor 42 are stopped. The resident gases within fuel processor 12 are dry and at an elevated pressure, which is desired for shut down condition, particularly with a CuZn water gas shift catalyst. [0044] Yet another alternative system is illustrated in FIG. 4 wherein a compressor may be eliminated from the fuel processor system, generally indicated at 10 ″′. Fuel processor system 10 ″′ is operated at sub-atmospheric pressures such that potential for air ingestion exists. Otherwise, the startup, shut down, turn down and transient operation are similar to fuel processor system 10 ″ illustrated in FIG. 3. An additional benefit of fuel processor system 10 ″′ is that a recirculated exhaust 302 can be made inert by providing just enough cathode exhaust 58 to catalytic combustor reactor 16 using a combustor air mass flow controller 304 for stoichiometric operation in catalytic combustor reactor 16 . [0045] A cathode back pressure regulator 306 is needed to match the pressure set by a back pressure regulator 308 downstream of catalytic combustor reactor 16 to ensure cathode exhaust 58 can be directed to catalytic combustor reactor 16 . An O 2 sensor 310 may be used in exhaust 312 to ensure stoichiometric operation. [0046] A unique capability of the aforementioned systems is the potential to operate without water addition. This is an advantage for a system that is to be started in ambient temperatures below 0° C., where water is not available. Because the system 10 ″′ operates at a high recirculation, this mode of operation is relatively inefficient at about 62%, however it may be used for short duration. [0047] It should be understood that features of the fuel processor systems illustrated in FIGS. 1 - 4 can be combined as needed for system requirements. For example, PrOx air 208 may preferably be delivered from stack air compressor 42 . That is, various combinations of the various systems described herein might be made depending upon the specific application. [0048] As should be appreciated from the foregoing discussion, the fuel processor systems of the present invention all include recirculation of fuel processor gases, such as reformate, anode exhaust, or combustor exhaust. This feature provides numerous advantages that are not present in conventional fuel processor systems. For example, the fuel processor systems of the present invention are capable of providing a large mass flow rate through the fuel processor to aid in heating the fuel processor components to the proper operating temperatures during startup. Moreover, during shut down, the fuel processor systems of the present invention enable the fuel processor to run dry and condense water from the reformate to avoid condensation on the catalysts and subsequently be shut down at an elevated pressure to prevent air ingestion upon cooling of the fuel processor. Still further, during turn down, the fuel processor systems of the present invention enable higher flow rates through the fuel processor and fuel cell stack to avoid auto-ignition in the inlet, reverse water gas shift in the PrOx, cell reversal in the fuel cell stack, and water collection in the fuel cell stack, all of which occur at reduced flow rates. During transient response, the fuel processor systems of the present invention, by circulating gases, enables the flow rate and pressure in the fuel processor to remain nearly constant, thereby minimizing the lag in transient response associated with filling or venting volumes in the fuel processor system. The ability to use recirculated gases, which contain water vapor as a product of reaction, enables the fuel processor to run without water injection. The fuel processor systems of the present invention enable rapid thermal start of the fuel processor without the complexity of multiple stages or risk of oxygen exposure. [0049] The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.	A fuel processor system capable of circulating fuel processor system gases, such as reformate, anode exhaust, and/or combustor exhaust, through the fuel processor to provide a number of distinct advantages. The fuel processor system having a plurality of fuel cells discharging an H 2 -containing anode effluent and an O 2 -containing cathode effluent. A fuel processor is also provided for converting a hydrogen-containing fuel to H 2 -containing reformate for fueling the plurality of fuel cells. A catalytic combustor is positioned in series downstream from the plurality of fuel cells and a vaporizer reactor is coupled to the catalytic combustor. A bypass passage is finally provided that interconnects an outlet of at least one of the group consisting of the fuel processor, the plurality of fuel cells, the catalytic combustor, and the vaporizer reactor to the inlet of the fuel processor. The bypass passage is operable to circulate a fuel processor system gas to the inlet of the fuel processor.	8
BACKGROUND OF THE INVENTION This invention relates generally to building construction, and more particularly to construction utilizing a reusable, inflatable form upon which there is applied a cementitious material to form a structure which may be a building or a part thereof. In the past building construction, utilizing inflatable forms over which a cementitious material is applied, had predominantly been of circular cross section, domed or of a generally spherical configurations. These limitations were imposed partially to take advantage of the structural integrity of the shapes, and also because of the ease of construction of the inflatable form and the resultant structure. Variations in dimensional integrity were offset by the lowered construction costs; however, the avoidance of conventional construction building designs was dictated by the unavailability of inflatable forms which could maintain straight sided walls, where desired. When inflation pressures were required to support a heavy load of the cementitious material, the wall and/or ceiling areas would bow. For multistoried buildings domed construction inhibited the effectiveness of a straight structure to define both the ceiling of the lower story and the floor of the upper story. Public acceptance of igloo type structures, curved outer walls of a building and other shapes that diverge from the conventional square or rectangular configurations has been dismal. However, there is a dire need for the economical, quick, efficient, structurally sound type of construction afforded by structures using inflatable forms in order to accomodate the world-wide population shifts and the attendant increased housing and industrial construction requirements. None of the prior art proposals have enabled the production of conventionally shaped buildings with the inflatable form technique, because of the failure of the industry to produce low cost forms of conventionally acceptable design with structural and dimensional integrity. SUMMARY OF THE INVENTION The invention comprises a novel, inflatable form that maintains dimensional integrity in a construction milieu to allow the production of buildings and/or modules having straight, substantially orthogonally related surfaces, thereby overcoming the deficiencies of the prior art. Accordingly, it is a primary object of this invention to produce an inflatable form for a building of cementitious material applied over the form, the form having straight sides, where desired, that maintain their dimensional stability under pressures required to support the said material. It is another object of this invention to provide a novel, inflatable construction form that utilizes a modular construction for the form, while the form itself can form a module of a structure to enable versatility in building design. It is still another object of this invention to provide an inflatable, reuseable form for building construction that allows for the preplacement of reinforcement, electricity, plumbing and communication equipment, etc. within the walls of the structure to provide for economical access for the installation of the devices to be attached thereto. It is a further object of this invention to provide an inflatable, reusable form for modular construction of a building that enables the joinder of separate modules to form separate rooms using doors to communicate one room with another wherein the door frames or frames of other communicating openings can be integrated into the resultant structure during the application of the cementitious material that forms the walls of the rooms. It is a still further object of this invention to provide an inflatable, reusable module for application of a cementitious material thereto to provide the walls and ceiling of the resultant structure, wherein window and door frames can be included in the construction by their application to the form prior to the application of said cementitious material. Another object of this invention involves the provision of a novel, inflatable modular form for building construction utilizing a cementitious material applied to the module for forming the walls and ceiling of the resultant structure, the module utilizing internal strapping to maintain the dimensional integrity of the module and resulting structure. Still another object of this invention involves a modular construction method and apparatus which enables the use of structural members at the periphery to assure right angled corners, the members being either fixed in or removable from the resultant structure. An additional object of this invention involves the use of a number of modules of different shapes capable of being secured one to another to produce a composite building module. A still additional object of this invention involves the provision of a building module capable of having a cementitious material applied thereto, comprising a three dimensional, hollow, structure of flexible material adapted to be collapsed and inflated, the shape of said module being maintained by internal means located and connected between internal surfaces of said structure and being of lengths calculated to maintain the geometric relationship of a desired shape, thereby preventing undesired distortion of the module when it is inflated. A further object of this invention involves providing an inflatable, six walled, parallelepiped building module comprising, a series of elongated, generally cruciform shaped members, each having a longitudinal axis substantially parallel with the others and lying in the same plane, each of said members being constrained to form a generally U-shaped channel of a supple material, impervious to air and water; means for joining adjacent sides of said channels together, to form a wall of said parallelepiped having four sides and edges, each of said walls of said parallelepiped being substantially identical to the wall opposite; means for sealing adjacent wall edges forming said parallelepiped together for rendering said parallelepiped air and watertight; and, means integral with said sides of said channels of one wall of a predetermined length and connecting with the channel sides opposite for maintaining the dimensional integrity of the parallelepiped when it is under pressure. A still further object of this invention involves providing a generally water and airtight, six sided, closed building module comprising, top, bottom and four side walls to form a closed module, each of said walls being a parallelogram formed of a series of elongated, coplanar, generally U-shaped channels adjacent one another, walls opposite one another being substantially identical; means for sealing each of said channels to its adjacent channels; means for sealing the sides of said parallelogram walls to walls adjacent thereto; and, means for maintaining a predetermined distance between opposite walls of said module. Another object of this invention is to produce an inflatable form for building construction that is easy and economical to produce of conventional, currently available materials that lend themselves to standard mass production manufacturing techniques. These and other advantages, features and objects of this invention will become more apparent from the following description taken in connection with the illustrative embodiments in the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS An inflatable form for buildings of a cementitious material in accordance with the present invention will be described infra, with reference to the accompanying drawings, which are not drawn to scale, and wherein like numerals denote like parts, of which FIG. 1 is a plan view of the material used as a modular unit for construction of a building module form; FIG. 2 is a schematic pictorial representation of the modular unit of FIG. 1 shown in the shape it assumes in the building module; FIG. 3 is a schematic representation of multiple units connected for forming a wall of a modular building form; FIG. 4 is an exploded view of a building module form for a parallelepiped structure; FIG. 5 is an axonometric view of a modular building form of the prior art when inflated to support a cementitious material to be applied thereto; FIG. 6 is an illustration of a method and apparatus for obtaining dimensional stability according to the present invention; FIGS. 7 and 8 are isometric views, partly in section, of alternative modes for obtaining dimensional stability; FIG. 9a is an isometric view of the inside of a wall section illustrating a smooth, straight, outer surface for cementitious material application; and apparatus at the periphery to assure right angled corners. FIG. 9b is an axonometric view of a portion of a building module utilizing a stretchable cover. The module having apparatus at the periphery to assure right angled corners; FIGS. 10 and 11 are isometric representations of a parallelepiped building module form readied for cementitious material application and as a completed building of multiple modules, respectively; and FIGS. 12 through 14 illustrate the possibilities of producing other shaped structures using the concepts of this invention. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2, there is shown a modular unit 10 of a building module comprising a rectangular piece of material 12 with a perimeter A,B,C,D,A, which has material at each corner of the rectangle cut and removed to form the generally cruciform shape as defined by the solid lines. The material 12 now has two end flaps 14 and a pair of side flaps 16 with a quarter round fillet 18 being provided to change the direction of curvature to allow for the downward slope of end flaps 14 at the intersection 19 of each end flap 14 with its adjacent side flaps 16. The material 12 should be supple and impervious to air and water as well as having ultra violet ray resistance. Stretch, tear and abrasion resistance are also desirable traits as is the ability of the material to be joined to others by standard techniques, such as by utilizing high frequency equipment, conventional thermal means, sewing or chemical adhesive gluing. Also shown in FIG. 1 is a dotted line indicating the joinder line for assembling other, substantially duplicate modular units 10 by one of the standard methods. FIG. 2 illustrates the modular unit in the configuration it normally assumes in the construction of a building module. FIG. 3 illustrates schematically a series of modular units 10 joined along the dotted lines illustrated in the previously described FIGS. 1 and 2. The series of modular units 10 could be used to form one wall or side 20 of a parallelepiped as is illustrated in FIG. 4. The fluted surface of the assembled modular units 10 might not conform to the desired motif of a wall formed over the surface. Accordingly, to achieve a smooth, straight surface a sheet of material, which could be similar to 12 of the modular unit, would be applied over the assembly of FIG. 3, as will be described later relative to FIGS. 9a and 9b. In FIG. 4 an inlet pipe or hose 22 to deliver pressurized air is provided through one of the walls 20 in a conventional manner. Each wall 20 is connected to its adjacent walls by securing and sealing together the adjacent end flaps 14 and also the wall side flaps 17 to form the corners. End flaps 14 adjacent a side flap 17 would be joined thereto. The wall side flaps 17 at the wall edges may be cut and reformed, as shown at 17 on FIG. 3, to avoid an excess of material, to form the corners of the parallelepiped. The arrows illustrate the wall portions and direction that they are to be moved to be joined. Spherical pieces of material 24 at the upper and lower corners at the joinder point of three walls are provided to seal the like shapes openings in the form so that it can be inflated. The axonometric view of FIG. 5 illustrates the problem of bowing of the walls of the parallelepiped when the form is inflated with sufficient pressure to support the cementitious material to be applied to the form. The dimensional integrity of the resultant structure is lost and the curvature would not be architecturally acceptable to the consumer. This invention rectifies the problem and provides standard shaped structures with orthogonally related walls, while allowing for curved and domed arrangements or portions thereof, only where desired. FIG. 6 illustrates a portion of a system for keeping the dimensional integrity of the module. In this Figure the side flaps 16, pairs of which have been joined together as illustrated in FIG. 3, have continuations from top to bottom opposed walls forming straps 26 for maintaining dimensional stability of the opposed walls 20, as shown. This would eliminate bowing when the surfaces 20 are under pressure. The strapping 26 could be separate strips of material sealed to opposed side flaps 16 or formed as part of extensions of some of all of the side flaps and joined to the opposite flap or an extension thereof. Although the straps 26 are shown predominantly emanating from straight edged side flaps, the flaps could preferably be fluted, as shown at 28, so that arcuate portions between the straps would avoid concentration of stress. It should be noted that the strap system and seals would be under tension, to take advantage of the maximum strength of the sealing or bonding of the materials. FIG. 7 illustrates by way of example sheets 30 instead of separate straps. With the building module in the position illustrated, this is, but does not have to be, vertically oriented. The sheets or side flap extensions 30 have holes 32 therethrough to accommodate straps 26, orthogonally oriented with respect to the sheets 30 and the opposed wall 20 when the parallelepiped module is inflated. Thus, the sheets 30 and straps 26 have dimensionally stabilized opposite walls 20 dimensionally. FIG. 8 is a view, partly in section, of an alternative embodiment utilizing straps 26 from each wall 20 to its opposite wall to accomplish the same effect as the embodiment of FIG. 7 in that the building module is dimensionally stabilized in all directions in which bowing may be expected. Since the embodiments thus far described show straight sided walls and ceilings, it might be considered desirable to avoid the fluting caused by the rounded portions of the modular units 10, as illustrated in FIGS. 2 and 3. One way of achieving this is to provide an unstretchable sheet 40, as illustrated in FIG. 9a. A series of modular units 10 would be assembled as in FIG. 3; however, the modular units 10 would be modified to eliminate that part of the end flaps 14, beyond the arcuate portions 18, having straight sides parallel with the side flap edges. The side of the sheet 40 would make up for the shortened portion by extending the appropriate distance beyond the new edge 15 of the end flaps to provide the edges to be joined to form the parallelepiped. Likewise, the wall side flaps 17 could be adjusted to allow sheet 40 to extend beyond to the appropriate length to provide for the sealing at the corners. The sealing of the spherical caps 24 to the matching openings, as illustrated in FIG. 4, would complete the external sealing procedure. Internally, the wall 20 would be sealed to sheet 40 along the line of tangency of sheet 40 and the modular unit 10 ending wall 20, and along the new edges 15 of the shortened end flaps 14. The result is now a channel with a substantially flat bottom portion between the side flaps 16. The cover or sheet 40 would now provide a smooth, flat surface to which the cementitious material is applied. In FIG. 9b there is provided a system and apparatus for not only providing a flat, non-fluted surface, for cementitious material application, but also apparatus for avoiding the rounds at all of the corners. The right angle elements 64 are used at the base (one of which is shown in its operative position and the other in a position of readiness to be slid onto a foundation or slab end against the building module) and at the vertical corners. Elements 64 may be of metal or plastic and either can be arranged to be a permanent part of the structure or can be removed for reuse. Instead of being right angled pieces, they could be any type of profile. In this instance the sheet 40 is made of a stretchable material, such as Tricot, thereby allowing the channels to take their normal, rounded shape. In both of FIGS. 9a and 9b the edge for joinder of two adjacent sheets 40 at a corner is notched to provide a sleeve 53 with openings, when desired, to enable access to the angle member 64. In FIG. 9b the assembly of module units 10 are sealed to the cover or sheet 40 along a line of tangency of sheet 40 with the corner channel portions at 41. Referring to FIG. 10, there is shown a room module 50 which may be used as a single structure or may be combined with other modules 70 to be interconnected to form a unitary structure of many rooms or assembled vertically for other building stories. After the room module 50 is attached in a conventional manner to a previously prepared base or foundation 51, it is inflated by known, conventional means, such as inlet hose 22 connected to the module 50 and a source of pressurized air 23 to at least partially inflate the module. Partial inflation would allow for easier installation of some panels. The module would then be ready for accommodating doors, windows, electric and plumbing accessories, air conditioning ducts, etc. As shown, there is a door frame 52, window frame 54, electric outlet 56, ceiling light 58, a skylight 60, and other connections for utilities which are common for the purposes for which the structure is built. The roof of the structure, to which a ceiling light 58 and skylight 60 are to be made integral may include a series of ceiling panels 62, which may have acoustic deadening properties, to which the accessories are fixed. Since there are gently rounded corners naturally occurring at the juncture of walls and ceiling of the building form module, corner angle beading or molding 64 of either plastic or metal is provided at both the top and bottom perimeters of the wall and may also be used at the internal or external corners within a room to be formed by the building module. Where the items 64 are not needed or required in the building structure, they could be made removable for reuse. For example, vertical corner angles are shown, inserted in a sleeve 53 formed as part of the building module, When the module is collapsed, the corner angles are laid on the diagonal of the parallelogram of the base or ceiling for storing and porterage to the building site for inflation. The bottom angle member may be a part of the base or slab on which the collapsed building module is to be erected. As shown, the angle members are perforated and, wire or clips may be used in conjunction therewith to place in a desired position the items to be included within or on the wall to be formed. If desired, wall paneling or gypsum board or any texturizing material may be utilized to provide an interior finished wall within the completed structure. The accessories and elements that are illustrated may be applied directly to the module by means of removable adhesive. Note that closets, kitchen cabinets, shower stalls, etc. may be provided with building modules made to size and attached to the room or building sized building modules to allow for built-in features where the external shape added on to the basic straight wall structure would be architecturally and esthetically pleasing. FIG. 11 illustrates the building module with the various stages for completing the building represented. For example, the build up of the exterior walls illustrates the possibility of using gypsum board 66, reinforcement rods or wire 77, cementitious material 74, insulation 76 (may be foamed in place) and a building finish 78. Additional storeys may be added as schematically illustrated in phantom. FIGS. 12 through 14 illustrate different shaped modules 80 utilizing the concepts of this invention. FIGS. 12 and 13 illustrate structures having a modified gambrel and a peaked roof, respectively, while FIG. 14 portrays a generally triangular floor plan. With structures that deviate from rectangular or square floor plans there are two preferred modes of attack. One is to produce an unitary module where, for the examples shown in FIGS. 12 and 13, the longitudinal straps would all be of the same length, while the vertical strapping would vary in accordance with the location of the straps to provide the straight slopes of the roofs. With regard to FIG. 14 a curved or toric roof formed by incurvated base modules 82 would have the vertically oriented straps vary in length to constrain the roof material of the module to conform to the desired curvature. If the end 82 of the module is to be curved or bowed, the horizontal strapping would also vary to obtain the desired curvature. An alternative to the above described, separate, unitary modules of FIGS. 12 through 14 contemplated by this invention is to separate the composite modules into, for example, modules of parallelepipeds that could be joined together to form polygonal structures of different sizes and modules that are triangular, domed, pyramidal, curved, or unitary combinations, where economy dictates, etc., that could be secured to the main module to produce a resultant composite module for any of the various building shapes desired. OPERATION The building module of this invention is brought in a collapsed condition to the building site, which has been prepared with a foundation or slab with appropriate means, which do not form a part of this invention, for fastening the building module thereto. A source of pressurized air is applied to the interior of the building module and the pressure is adjusted to acommodate the weight of the requisite amount of cementitious material to be applied to the module. Additional building modules may be applied to the same slab and module for other features, such as angled roofs, curved walls or roofs, closets, showers, cabinets, etc., would also be secured to the base and/or building module, where required. Frames for opeings between connecting modules are placed to be between and in contact with each of the adjacent modules, and utility structures, may be adhesively taped or otherwise releasably applied to the appropriate building modules as well as other reinforcing means or corner angle members to become integrated into the structure. At this point a cementitious material, commercially available, is applied to complete the external walls and roof of one story buildings or the ceiling of the first story and the floor of the second, etc, When two building modules form interconnecting rooms with a common wall, the common wall is usually formed between the two building modules after application of the cementitious material forming the exterior of the structure. A bridging member may be used to provide a base for the cementitious material at the space at the juncture of the modules. The resultant structure would conform to conventional architectural designs and would lend itself to the inclusion of parapets, domed sections and other modernistic shapes not easily fabricated by construction techniques other than by the use of inflatable building modules. The versatility of the concept of this invention also includes polygonal floor plans and polyhedron structures. The utilization of the building modules of this invention enable the economical, architecturally handsome, speedy construction of structures not capable previously of being accomplished. Although the invention has been illustrated in the accompanying drawings and described in the foregoing specification in terms of preferred embodiments, the invention is not limited thereto. It will be apparent to those skilled in this art that certain changes, modifications, and substitutions can be made without departing from the spirit and scope of the appended claims.	Inflatable formwork mould for supporting one or more applications of hardening building materials, applied while still in a plastic state. The formwork mould is characterized in that at least two of its sides (20) consist of elongate, cross-shaped, modular base element (10), each having a longitudinal axis parallel to the one adjacent thereto; each base element (10) is made to conform to the shape of a U-shaped groove (12), and is produced from an airtight, flexible material impermeable to water and assembled by welding, stitching, bonding and the like. A link system (26) joins a number of base elements constituting one side to a corresponding number of base elements opposite forming the opposite side (20). The links (26) of a predefined length, preserve the entire geometrical relationship between the two opposing sides (20) of the inflatable formwork mould. An external envelope optionally made from an extensible material produces a smooth, plane or curved moulding surface. The invention adapts the technique of inflatable formwork to all kinds of architectural forms.	4
CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of U.S. patent application Ser. No. 608,604 filed Aug. 28, 1975 and now abandoned. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention is concerned with an improved catalytic process for the demetalation and desulfurization of petroleum oils, preferably those residual fractions with undesirably high metals and/or sulfur contents. More particularly, the invention utilizes a demetalation-desulfurization catalyst characterized by novel specifications including pore size distribution. Additionally, this invention involves a method for the preparation of a demetalation-desulfurization catalyst comprising a Group VIB metal and an iron group metal composited with a gamma alumina that contains dispersed Delta and/or Theta phase alumina, said catalyst having a specific pore size distribution, and other specified characteristics described hereinbelow. 2. Description of the Prior Art Residual petroleum oil fractions produced by atmospheric or vacuum distillation of crude petroleum are characterized by relatively high metals and sulfur content. This comes about because practically all of the metals present in the original crude remain in the residual fraction, and a disproportionate amount of sulfur in the original crude oil also remains in that fraction. Principal metal contaminants are nickel and vanadium, with iron and small amounts of copper also sometimes present. Additionally, trace amounts of zinc and sodium are found in some feedstocks. The high metals content of the residual fractions generally preclude their effective use as charge stocks for subsequent catalytic processing such as catalytic cracking and hydrocracking. This is so because the metal contaminants deposit on the special catalysts for these processes and cause the premature aging of the catalyst and/or formation of inordinate amounts of coke, dry gas and hydrogen. It is current practice to upgrade certain residual fractions by a pyrolitic operation known as coking. In this operation the residuum is destructively distilled to produce distillates of low metals content and leave behind a solid coke fraction that contains most of the metals. Coking is typically carried out in a reactor or drum operated at about 800° to 1100° F temperature and a pressure of one to ten atmospheres. The economic value of the coke by-product is determined by its quality, especially its sulfur and metals content. Excessively high levels of these contaminants makes the coke useful only as low-valued fuel. In contrast, cokes of low metals content, for example up to about 100 p.p.m. (parts-per-million by weight) of nickel and vanadium, and containing less than about 2 weight percent sulfur may be used in high valued metallurgical, electrical, and mechanical applications. Certain residual fractions are currently subjected to visbreaking, which is a heat treatment of milder conditions than used in coking, in order to reduce their viscosity and make them more suitable as fuels. Again, excessive sulfur content sometimes limits the value of the product. Residual fractions are sometimes used directly as fuels. For this use, a high sulfur content in many cases is unacceptable for ecological reasons. At present, catalytic cracking is generally done utilizing hydrocarbon chargestocks lighter than residual fractions which generally have an API gravity less than 20. Typical cracking chargestocks are coker and/or crude unit gas oils, vacuum tower overhead, etc., the feedstock having an API gravity from about 15 to about 45. Since these cracking chargestocks are distillates, they do not contain significant proportions of the large molecules in which the metals are concentrated. Such cracking is commonly carried out in a reactor operated at a temperature of about 800° to 1500° F, a pressure of about 1 to 5 atmospheres, and a space velocity of about 1 to 1000 WHSV. The amount of metals present in a given hydrocarbon stream is often expressed as a chargestock's "metals factor". This factor is equal to the sum of the metals concentrations, in parts per million, of iron and vanadium plus ten times the concentration of nickel and copper in parts per million, and is expressed in equation form as follows: F.sub. m = Fe + V + 10 (Ni + Cu) Conventionally, a chargestock having a metals factor Of 2.5 or less is considered particularly suitable for catalytic cracking. Nonetheless, streams with a metals factor of 2.5 to 25, or even 2.5 to 50, may be used to blend with or as all of the feedstock to a catalytic cracker, since chargestocks with metals factors greater than 2.5 in some circumstances may be used to advantage, for instance with the newer fluid cracking techniques. In any case, the residual fractions of typical crudes will require treatment to reduce the metals factor. As an example, a typical Kuwait crude, considered of average metals content, has a metals factor of about 75 to about 100. As almost all of the metals are combined with the residual fraction of a crude stock, it is clear that at least about 80% of the metals and preferably at least 90% needs to be removed to produce fractions (having a metals factor of about 2.5 to 50) suitable for cracking chargestocks. Metals and sulfur contaminants would present similar problems with regard to hydrocracking operations which are typically carried out on chargestocks even lighter than those charged to a cracking unit. Typical hydrocracking reactor conditions consist of a temperature of 400° to 1000° F and a pressure of 100 to 3500 p.s.i.g. It is evident that there is considerable need for an efficient method to reduce the metals and/or sulfur content of petroleum oils, and particularly of residual fractions of these oils. While the technology to accomplish this for distillate fractions has been advanced considerably, attempts to apply this technology to residual fractions generally fail due to very rapid deactivation of the catalyst, presumably by metals contaminants. U.S. Pat. No. 3,770,617 issued Nov. 6, 1973 describes a hydrodesulfurization process that employs a catalyst having an oxide or sulfide of a Group VIB and/or Group VIII metal on an alumina support characterized by a bimodal pore size range. SUMMARY OF THE INVENTION It has now been found that hydrocarbon oils containing both metals and sulfur contaminants may be very effectively demetalized and desulfurized, with only moderate change in selectivity as the catalyst ages, by contact in the presence of hydrogen under hydrotreating conditions with a catalyst more fully described hereinbelow, comprising a hydrogenation component composited with a substantially non-acidic alumina support consisting essentially of a mixture of gamma alumina with Delta and/or Theta phase alumina, the catalyst being further characterized by a particular pore size distribution. In particular, the catalyst has at least 45% of its pore volume in pores 30 to 150A diameter, at least 10% of its pore volume in pores less than 30A diameter, at least 15% of its pore volume in pores greater than 300A diameter, and a surface area of 125 to about 210 m 2 /g (square meters per gram). The hydrogenation component preferably comprises the oxides or sulfides of a Group VIB metal and an iron group metal, as more fully described hereinbelow. For best results in the process of this invention, the catalyst has a total pore volume of 0.4 to 0.65 cc/gm (cubic centimeters per gram of catalyst), and has at least about 10% of its pore volume in pores greater than 150 up to 300A diameter. The pore volumes referred to herein, with the exception for pores less than 30A diameter, are those volumes determined by mercury porosimeter using techniques well known to those skilled in the art of catalyst preparation. Pore volume in pores less than 30A is determined by subtracting the pore volume accessible to mercury from the total pore volume determined independently. With the specified catalyst, and under the reaction conditions hereinafter to be described, high efficiency for both demetalation and desulfurization are achieved with unusually slow aging, in balanced fashion, of both these conversions. The catalyst of this invention is prepared by a sequence of calcining procedures, more fully described hereinafter, that induces the formation of Delta and/or Theta phase alumina. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a set of aging curves. FIG. 2 is a set of curves showing changes in selectivity with days on stream. FIG. 3 is an alumina phase transformation diagram. BRIEF DESCRIPTION OF THE INVENTION The catalyst of this invention is prepared by precalcining a high-porosity gamma type alumina, or an alumina hydrate such as boehmite, at a sufficiently high temperature, as hereinafter described, to induce the formation of Delta and/or Theta phase alumina; intimately mixing this precalcined alumina with a boehmite type alumina hydrate; and, recalcining the mixed aluminas to dehydrate the boehmite and convert it to gamma alumina. The hydrogenation component is introduced at one or more appropriate stages during or after the preparation of the alumina support, as will be illustrated hereinafter. FIG. 3 of the drawing illustrates the temperatures at which suitable forms of alumina are transformed to the Delta and/or Theta phase, or to the gamma phase, as described by Newsome et al. in "Alumina Properties" published by Alcoa Research Laboratories, 1960. As a result of the particular calcination and mixing sequences utilized in this invention, an alumina support is formed that consists essentially of an intimate mixture of gamma alumina with Delta and/or Theta phase alumina. The Delta and Theta alumina phases are formed at high temperatures, as shown in FIG. 3. The expression "Delta and/or Theta phase", as used herein, signifies either phase alone or both phases together. Thus, the intimate mixture contemplated include gamma with Theta, gamma with Delta, and gamma with both Delta and Theta phases. DETAILED DESCRIPTION OF THE INVENTION The hydrocarbon feed to the process of this invention can be a whole crude. However, since the high metal and sulfur components of a crude oil tend to be concentrated in the higher boiling fractions, the present process more commonly will be applied to a bottoms fraction of a petroleum oil, i.e., one which is obtained by atmospheric distillation of a crude petroleum oil to remove lower boiling materials such as naphtha and furnace oil, or by vacuum distillation of an atmospheric residue to remove gas oil. Typical residues to which the present invention is applicable will normally be substantially composed of residual hydrocarbons boiling above 650° F and containing a substantial quantity of asphaltic materials. Thus, the chargestock can be one having an initial or 5 percent boiling point somewhat below 650° F, provided that a substantial proportion, for example, about 70 or 80 percent by volume, or its hydrocarbon components boil above 650° F. A hydrocarbon stock having a 50 percent boiling point of about 900° F and which contains asphaltic materials, 4% by weight sulfur and 51 ppm nickel and vanadium is illustrative of such chargestock. Typical process conditions may be defined as contacting a metal and/or sulfur contaminant containing chargestock with this invention's catalyst under a hydrogen pressure of about 500 to 3000 p.s.i.g., at 600° to 850° F temperature, and 0.1 to 5 LHSV (i.e. 0.1 to 5 volumes of charge-stock per volume of catalyst per hour). The hydrogen gas which is used during the hydrodemetalation-hydrodesulfurization is circulated at a rate between about 1,000 and 15,000 s.c.f./bbl. of feed and preferably between about 3,000 and 8,000 s.c.f./bbl. The hydrogen purity may vary from about 60 to 100 percent. If the hydrogen is recycled, which is customary, it is desirable to provide for bleeding off a portion of the recycle gas and to add makeup hydrogen in order to maintain the hydrogen purity within the range specified. The recycled gas is usually washed with a chemical absorbent for hydrogen sulfide or otherwise treated in known manner to reduce the hydrogen sulfide content thereof prior to recycling. For the purpose of this invention, it is preferred to operate with catalyst particles such as 1/32 inch extrudate or the equivalent disposed in one or more fixed beds. Furthermore, the catalyst described herein may be effectively used as the sole catalyst in the process of this invention. Alternatively, a dual bed arrangement such as described in U.S. Pat. No. 4,016,067 issued Apr. 5, 1977 may be used. The catalyst may be presulfided, if desired, by any of the techniques known to those skilled in the art. The process of this invention is illustrated by aging tests using an atmospheric residual oil from Light Arabian crude. Each of the aging runs was performed at 2000 psi hydrogen pressure, 0.4-0.5 L.H.S.V. space velocity and 5000 SCF/B hydrogen circulation. Temperatures were initially set at 725° F, and then adjusted to maintain below 2 ppm metals (nickel + vanadium) and below 0.5% at sulfur in the hydrotreated products. The Light Arabian chargestock contained 25 ppm metals and 2.7 wt.% sulfur. The properties of the catalysts used in the tests are summarized in Table 1. Catalysts A and B are illustrative of the present invention. Catalyst C is a prior art catalyst of the type described in U.S. Pat. No. 3,876,523 issued Apr. 8, 1975 and characterized by good initial activity for both demetalation and desulfurization. Catalyst D is a commercial hydrodesulfurization catalyst with too low a demetalation activity to be useful in the process of this invention. Table 1______________________________________Catalyst Properties Prior Art A B C D______________________________________Catalyst (SMO (SMO 8112) 8114)CoO, wt. % 3.5 3.5 3.4 3.4MoO.sub.3, wt. % 9.7 9.7 10.6 13.4Surface Area, m.sup.2 /g 196 144 104 286Real Density, g/cc 3.32 3.41 3.64 3.33Particle Density, g/cc 1.22 1.28 1.31 1.15Pore Volume, cc/g .52 .49 .49 .49% of pore volume inpores with diameters (A) 0-30 13 12 4 730-50 15 5 2 28 50-100 40 29 8 62100-200 7 23 67 1200-300 7 12 10 0 300+ 17 19 9 2 100 100 100 100______________________________________ The results of the aging tests are summarized in FIGS. 1 and 2 of the drawing. The improved aging behavior of the process of this invention and the initially good balance of desulfurization and demetalation activities, which allow a low start-of-run temperature, are shown in FIG. 1. FIG. 2 of the drawing shows the improved maintenance of the initial balance of activities with the process of this invention as compared with Catalyst C which has an initially good balance. Catalyst D maintains its initial balance with aging, but has little or no useful life because of its very limited demetalation activity. The catalyst useful in this invention comprises a hydrogenation component composited with a support consisting essentially of an intimate mixture of gamma alumina with Delta and/or Theta phase alumina. The hydrogenation component can be any known material or combination thereof effective to demetalize and desulfurize the chargestock under the reaction conditions described herein. The preferred and commonly used hydrogenation component comprises the oxides or sulfides of an iron group metal and a Group VIB metal. The iron group metals as used herein include iron, cobalt, and nickel, of which cobalt and nickel are particularly preferred; and the Group VIB metals include chromium, molybdenum, and tungsten, of which molybdenum and tungsten are particularly preferred. Particularly preferred combinations include cobalt and molybdenum or nickel and molybdenum. The catalyst compositions contain the preferred combinations of metals, computed as oxide and based on total weight of catalyst, in amounts of about 2 wt.% to about 6 wt.% cobalt oxide (CoO) or nickel oxide (NiO) and from about 8 wt.% to about 16 wt.% molybdenum trioxide (MoO 3 ), the remainder being the alumina support. Compositing the hydrogenation component with the alumina may be done by any of the impregnation or other compositing techniques known in the art. The alumina support preferably is of the non-acidic type, and in particular should contain less than 0.5 wt.% silica. Catalysts having the pore size distribution of this invention are prepared by calcining preferably a low density gamma alumina at a temperature of 1600° to 2000° F for 0.25 to 10 hours to induce the formation of some high temperature Delta or Theta phase alumina. The preferred low density alumina has at least 35% of its pore volume in pores greater than 100A diameter. The product is ground, if necessary, to pass a standard 100 mesh Tyler sieve. This powder is then mixed with 40% to 125% of its own weight, on an anhydrous basis, of alpha-alumina monohydrate powder, sometimes known as technical grade Boehmite, sold commercially as Catapal SB. The composite is pelleted or extruded and recalcined 1 to 20 hours at a temperature 900° to 1400° F to convert the alpha-alumina monohydrate to the gamma form alumina. This procedure, involving a first calcination, mixing, and a second calcination, as prescribed, forms the support which consists essentially of an intimate mixture of gamma alumina Delta and/or Theta phase alumina. Impregnation with salts of the hereinabove described metals may be done at various stages in the preparation. The catalysts of this invention also may be prepared by calcining technical grade Boehmite at 1600° to 2000° F for 0.25 to 10 hours to induce the formation of an alumina comprising Delta and/or Theta phase alumina, compositing the calcined product with 40% to 125% of its own weight, on an anhydrous basis, of alpha-alumina monohydrate, pelleting or extruding the composite, and calcining the pellets or extrudate for 1 to 20 hours at 900° to 1400° F. Preparation of the catalysts of this invention are described in the examples which follow, it being understood that these are illustrative and no way restricting on the scope of this invention. Parts are by weight on an anhydrous basis unless specified to be otherwise. EXAMPLE I (SMO-8112) The following example illustrates the preparation of one catalyst of this invention. Nine-hundred grams of a high porosity, low density gamma alumina is placed in a shallow dish, rapidly brought to 1950° F, and held at that temperature for 2 hours to induce formation of Delta and/or Theta phase alumina. The following Table A shows the changes in physical characteristics that occurred in the calcining procedure. TABLE A______________________________________ Calcined Gamma Alumina Gamma AluminaPore Volume in Pores of cc/g % cc/g %______________________________________0-30A diameter (0.126) 13.0 0.128 17.730-50 diameter 0.035 3.6 0.011 1.550-80 diameter 0.165 17.2 0.005 0.780-100 diameter 0.138 14.3 0.005 0.7100-150 diameter 0.287 29.9 0.024 3.3150-200 diameter 0.105 10.9 0.108 14.9200-300 diameter 0.034 3.5 0.187 25.9300+ diameter 0.073 7.6 0.255 35.3 (0.966) 100.0 0.723 100.0______________________________________ The calcined product was milled and screened to pass through a 100 mesh Tyler standard sieve. 250 grams of the powder was placed in a laboratory mixer, and 138 milliliters of solution containing 37.1 grams of ammonium molybdate (para) (NH 4 ) 6 Mo 7 O 24 .4H 2 O. was added and allowed to mix for one quarter hour. To the material in the mixer was then added 501 grams (on an anhydrous basis) of Boehmite, (Continental Oil Company, Catapal SB) which is an alpha alumina monohydrate. 477 milliliters of a solution that contained 74.2 grams of ammonium molybdate was then added to the contents of the mixer and allowed to mix for an additional one quarter of an hour. The material was then extruded to form 1/32 inch diameter pellets in an auger extruder. The extrudate was dried at 250° and the temperature was then raised to 1000° at 5° F per minute and held at that temperature for three hours. The material at this point had a packed density of 0.62 g/cc and a water capacity (to incipient wetness) of 0.54 cc/g. To 450 g. of the material was added 242 milliliters of solution containing 63.4 grams of cobalt nitrate hexahydrate, which impregnated the pellets to incipient wetness. This material was then dried at 250°. The dried pellets were heated at 5° per minute to 1000° F and calcined at this temperature for 10 hours. The properties of the catalyst and the pore size distribution were as follows: ______________________________________Surface Area 196 m.sup.2 /gReal Density 3.32 g/ccParticle density 1.22 g/ccPore volume 0.519 cc/gPore diameter (Av.) 106APacked density 0.69 g/cc______________________________________ The pore size distribution, determined by mercury porosimeter was as follows: ______________________________________Pore Volume inPores of cc/g %______________________________________ 0-30A diameter 0.068 13.130-50 diameter 0.080 15.450-80 diameter 0.179 34.5 80-100 diameter 0.028 5.4100-150 diameter 0.015 2.9150-200 diameter 0.023 4.4200-300 diameter 0.036 6.9 300+ diameter 0.090 17.4 0.575 100.0______________________________________ EXAMPLE II (SMO-8114) High temperature calcined gamma alumina powder was prepared as in Example I. To 502 grams of this material was added 326 milliliters of solution containing 74.2 grams of ammonium molybdate. This material was blended in a Lancaster mixer for one-quarter hour. 336 grams (about 250 grams on an anhydrous basis) of alpha alumina monohydrate powder (Catapal SB, manufactured by Continental Oil Company) was added to the mixer followed by 213 milliliters of solution containing 37.1 grams of ammonium molybdate. After mixing for one-quarter hour, the blend was extruded as in Example I and dried and calcined at 1000° F for 3 hours. This intermediate material had a packed density of 0.68 g/cc and a water capacity of 0.49 cc/g. To 450 grams of this intermediate product was added 223 milliliters of solution containing 63.4 grams of cobalt nitrate, CO(NO 3 ) 2 .6H 2 O. The impregnated intermediate was dried at 250° F, and calcined for 10 hours at 1000° F. The catalyst thus formed had the following properties: ______________________________________Packed density 0.75 g/ccReal density 3.41 g/ccParticle density 1.28 g/ccPore volume 0.490 cc/gPore diameter 136ASurface area 144 m.sup.2 /g______________________________________ The pore size distribution by mercury porosimeter was found to be: ______________________________________Pore Volume inPores of cc/g %______________________________________0-30A diameter 0.059 12.030-50 diameter 0.027 5.550-80 diameter .074 15.180-100 diameter 0.068 13.9100-150 diameter 0.068 13.9150-200 diameter 0.043 8.8200-300 diameter 0.059 12.0300 diameter 0.092 18.8 0.530 100.0______________________________________ EXAMPLE III (SMO-8454) 1800 grams of alpha alumina monohydrate powder (Catapal SB) was calcined at 1700° F for 15 minutes. 300 grams of the calcined product were blended in a mixer with 812 grams (600 g anhydrous basis) of uncalcined alpha alumina monohydrate powder. To the mixer was added 800 milliliters of solution containing 44.1 grams of aluminum nitrate nonahydrate and the blend allowed to mix for 10 minutes. The resultant blend was extruded as in Example I, and the extrudate dried at 250 F. The dried extrudate was calcined in flowing air for 4 hours at 1000° F, after heating up to temperature at 5° per minute. The resultant intermediate had the following properties: ______________________________________Real Density 3.38 g/ccParticle Density 1.06 g/ccPore volume 0.648 cc/gPore diameter 123ASurface Area 211 m.sup.2 /g______________________________________ To one hundred grams of this intermediate was added 65 milliliters of solution containing 13.9 grams of ammonium molybdate. The product was dried at 250° F. To this dried product was added 58 milliliters of solution containing 15.7 grams of cobalt nitrate crystals, Co(NO 3 ) 2 .6H 2 O. The cobalt impregnated material was dried at 250° F, heated to 1000° F at the rate of 5° F per minute, and calcined for 10 hours at 1000° F. This final catalyst had the following properties: ______________________________________Packed Density 0.71 g/ccReal Density 3.39 g/ccParticle Density 1.21 g/ccPore Volume 0.531 cc/gSurface Area 186 m.sup.2 /gPore Diameter 114 A______________________________________ The distribution of pore diameters was as follows: ______________________________________Pore Volume inPores of cc/g %______________________________________ 0-30A diameter 0.072 13.6 30-50 diameter 0.020 3.8 50-80 diameter 0.207 39.0 80-100 diameter 0.047 8.9100-150 diameter 0.091 17.0150-200 diameter 0.005 0.9200-300 diameter 0.000 0.0300+ 0.089 16.8 0.531 100.0______________________________________	This invention is concerned with removing metal and sulfur contaminants from residual oil fractions by catalytic contact with an improved catalyst comprising the oxides or sulfides of a Group VIB metal and an iron group metal supported on an alumina that contains dispersed Delta and/or Theta phase alumina, the catalyst having at least 45% of its pore volume in pores 30 to 150A diameter, at least 10% of its pore volume in pores less than 30A diameter, and at least 15% of its pore volume in pores greater than 300A diameter. The process can be used to prepare feedstock for catalytic cracking.	1
BACKGROUND OF THE INVENTION The present invention relates to a method and apparatus for reducing the rate of loss of a sacrificial protective anode in a water storage tank as a result of undesirable cathodic reactions and, more particularly, to a method and apparatus for reducing the protective anode current and dissolution of the anode as a result of the cathodic effect of the metal-jacketed heating element in an electric water heater. A typical water heater includes a storage tank made of ferrous metal and lined internally with a glass-like porcelain enamel to protect the metal from corrosion. Nevertheless, the protective lining may have imperfections or, of necessity, not entirely cover the ferrous metal interior, such that an electrolytic corrosion cell may be established as a result of dissolved solids in the stored water leading to corrosion of the exposed ferrous metal and substantial reduced service life of the water heater. The water in the tank may be heated by gas or electric power and it is well known that uninhibited corrosion is substantially enhanced in the presence of hot water. It is also well known in the art to utilize a sacrificial anode within the tank to protect against corrosion of the ferrous metal tank interior. The sacrificial anode is selected from a material which is electronegative with respect to the tank and by galvanic reaction maintains the tank metal in a passive and non-corrosive state. Alternatively, a protective anode may be powered by providing a source of electrical potential to establish a positive voltage differential between the anode and the tank. In an electric water heater, an electric heating element is attached to the tank wall and extends into the tank to provide direct heating of the water. The heating element typically includes an internal high resistance heating element wire surrounded by a suitable insulating material and enclosed in a metal jacket such that the jacket is completely insulated from the internal heating element. Power for the heating element is typically supplied from a conventional 110 or 220 volt AC source. When the exterior metal jacket of the heating element is immersed in the water in the tank, it imposes an electrical load on the protective anode in the same manner as the exposed ferrous metal interior of the tank. As a result, the protective anode current is increased and the anode is subject to more rapid dissolution. Therefore, the life of the anode and thus the water heater are substantially shortened. In a typical electric water heater, less than half the protective anode current is needed to protect the tank interior with the remaining current resulting from the additional load imposed by the heating element jacket. However, the heating element jacket typically comprises or is plated with a metal more electropositive than the tank metal and thus does not require the same level of cathodic protection. In addition, heating elements are relatively inexpensive and easy to replace. In addition to the large current draw imposed on the protective anode by the heating element jacket, the heating element also creates a "shadowing" effect on any exposed interior portions of the tank in the vicinity of the heating element. As a result, anode current which might otherwise protect these areas of the tank flows instead to the heating element jacket and leaves the metal tank wall portions in this area with inadequate protection. It would be most desirable, therefore, to reduce the electrical load which the heating element jacket imposes on the protective anode in an electric hot water heater. One way would be to simply electrically insulate the heating element jacket from the tank. However, the metal tank is typically grounded and, for safety reasons, a conductive path must be provided between the heating element jacket and the tank to provide a shunt for an overvoltage condition, such as would occur if damage to the heating element resulted in a short between the interior element wire and the metal jacket. Another solution to the problem would be to provide a resistance connection between the heating element jacket and the tank wall to reduce the anode current. However, to effectively reduce the anode current draw, the resistance would be too great to provide an adequate ground path in the event of an overload condition. It would also be possible to establish an impressed voltage differential between the heating element jacket and the tank wall, with the former maintained positive with respect to the latter. However, with the heating element jacket otherwise electrically insulated from the tank to allow maintenance of the potential difference, a conductive path for an overvoltage condition would not be available. Thus, there remains a need for a practical solution to the excessive current draw and shadowing effect which an electric heating element jacket causes in an anodically protected electric water heater. SUMMARY OF THE INVENTION In accordance with the present invention, the increase in protective anode current and the shadowing effect created by the metal jacket of an electric heating element in a water heater are eliminated or substantially reduced with a system that imposes a low voltage differential between the heating element jacket and the tank and includes a relatively low resistance current path which will provide a direct conductive path between the jacket and the tank wall in the event of an overvoltage condition, such as a short circuit between the internal high voltage heating element wire and the heating element jacket. The method and apparatus of the present invention require that the normally direct conductive connection provided by mounting the heating element directly to the tank wall be eliminated and an electrically insulating separation be inserted therebetween. An external source of direct current potential is provided and an appropriate circuit is utilized to apply a potential from the source between the jacket and the tank such that the jacket is maintained positive with respect to the tank. The circuit also provides an overvoltage current path between the jacket and the tank wall. The overvoltage current path preferably comprises a resistance connection between the jacket and the tank wall. The circuit also preferably includes a potentiometric control with a variable resistance operable to simultaneously vary the applied potential between the jacket and the tank and the resistance of the overvoltage current path between the jacket and tank. The method of the present invention broadly comprises the steps of insulating the heating element jacket from the tank wall, imposing a low voltage differential between the jacket and the tank maintaining the former positive with respect to the latter, and providing a separate relatively low resistance path between the jacket and the tank which is conducting under high overvoltage conditions. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representation of an electrically heated water heater in which the tank is provided with a protective anode and the heating element is provided with the protective circuit of the present invention. FIG. 2 is an enlarged detail of a section through the tank wall of a water heater showing the heating element and tank connected to the protective bias circuit of the present invention. FIG. 3 is a schematic of an alternate embodiment of the protective circuit of the present invention utilizing the power source for the heating element to provide the power for the protective circuit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIGS. 1 and 2, an electric water heater 10 includes a tank 11 made of a ferrous metal, i.e. steel, in which water is stored and heated. The tank includes a cold water inlet 12 and heated water outlet 13, both of a conventional construction. To provide corrosion protection to the interior of the tank, a glass or ceramic lining 14 covers substantially the entire interior of the tank. However, as is well known in the art, minute cracks or other imperfections may develop in the lining 14 or certain portions of the metal tank may not be covered by the lining 14, such that the metal is exposed to the water in the tank. As a result of the usual dissolved minerals and other solids in the water, electrolytic corrosion of the exposed tank will occur absent appropriate protection. A protective anode 15 is mounted on and extends into the interior of the tank 11 to provide corrosion protection in a known manner. The anode 15 may be of a passive type, as shown, wherein it is constructed of a metal more electronegative than the tank metal to establish an electrochemical couple with the anode 15 acting as a sacrificial electrode to protect the interior tank wall. Alternately, the anode 15 could be externally powered to provide a positive potential difference between the anode and the tank wall without regard to the type of metal from which the anode is constructed. In either case, oxidative dissolution of the anode over time protects the exposed interior metal portions of the tank. In the electric water heater 10, an electric heating element 16 is mounted in the wall of the tank 11 and extends into the tank interior to contact and heat the water stored therein. In accordance with conventional construction, the heating element 16 includes a high resistance element wire 17 disposed within a U-shaped metal jacket 18 and insulated therefrom by an interior layer of a granular refractory material 19, such as magnesium oxide. The opposite ends of the heating element wire 17 are typically attached to a source of alternating current at 220 or 10 volts. The heating element jacket 18 is typically made of copper and may additionally be tin or zinc plated. The outer end of the heating element 16 includes a mounting plug 20 for supporting the heating element jacket and attaching the heating element to the tank wall 11. The legs of the heating element jacket extend through the mounting plug 20 and are electrically insulated from the conductive metal plug 0 by insulating sleeves 21. The ends of the heating element wire 17 also extend through the mounting plug to an insulating terminal mount 22 on the outside thereof for connection to a pair of terminals 23 from the AC power source. The mounting plug 20 is provided with exterior threads 24 for attachment to an internally threaded spud or mounting ring 25 which is welded or otherwise attached directly to the tank wall 11. It should be pointed out that, in conventional construction, the insulating sleeves 21 between the heating element jacket 18 and the mounting plug 20 are eliminated, such that there is a direct conductive connection between the jacket and the tank wall. In addition, the tank wall is typically grounded, as at 26. Should damage to or a defect in the heating element result in the wire 17 coming in direct contact with the jacket 18, the prior art construction allows the high voltage current imposed on the heating element jacket to be shunted directly to ground via the conductive connection to the tank wall. The exposed metal jacket 18 which extends into the water in the tank 11 provides a substantial bare metal surface area which, if conductively connected to the tank, induces a substantially higher current in the protective anode 15 resulting in more rapid dissolution thereof. As previously indicated, merely insulating the element jacket 18 from the tank wall, as with the insulating sleeves 21, would substantially reduce or eliminate the current drain by the heating element on the anode. However, the conductive path between the heating element and ground in the event of an overvoltage condition would be lost. In the preferred embodiment of the present invention, a source of controlled DC potential 27 is operatively attached to the heating element jacket and the tank wall via protective circuit 28 to simultaneously provide both an imposed positive potential on the heating element jacket 18 and an overvoltage current path between the jacket and the tank wall. The combined effect is to eliminate or substantially limit the unnecessary current drain by the heating element on the sacrificial anode 15 and protect against the potential electrical hazard resulting from a short circuit between the heating element wire 17 and the jacket 18. In particular, the DC power supply 27 may comprise a conventional 6 volt battery 30, the positive terminal of which is connected directly to the heating element jacket 18 via positive lead 29 and a jacket terminal 31 on the exterior terminal mount 22. The remainder of the circuit 28 comprises a potentiometer 32 including a variable resistance element 33 having a variable contact 34 connected directly to the tank wall 11. The first fixed leg 35 of the variable resistance 33 is connected to the positive lead between the battery terminal and the element jacket. The second fixed leg 36 of the variable resistor is connected to the negative terminal lead of the battery 30. The battery 30 causes a voltage potential to be impressed between the heating element jacket and the tank wall through the water in the tank. The heating element jacket is maintained positive as a result of its direct connection to the positive terminal of the battery 30 and the value of the potential difference will depend upon the position of the variable contact 34 and the conductivity of the water in the tank. In the circuit 28 shown in the drawing, a 6 volt battery 30 having a nominal six amp-hour rating is connected as shown to the potentiometer 32 having a variable resistance ranging from 0 to 50 ohms. The variable contact 34 is adjusted until the current flow between anode 15 and tank wall 11 is reduced by approximately one-half. As indicated previously, the impressed potential difference between the heating element jacket and the tank wall will vary depending upon the conductivity of the water varying with the temperature thereof, and other environmental factors. For example, a balanced condition as described above and a potential difference of 0.1 to 0.7 volts results from varying the resistance in the leg 35 in the range of between six ohms and 32 ohms. The indicated potential difference is adequate to effectively eliminate the excessive current drain by the heating element jacket on the anode 15. However, should an overvoltage condition occur in the heating element jacket, a relatively low resistance current path to ground 26 is provided via the first leg 35 of the variable resistance, the variable contact 34 and the tank wall 11. Referring also to FIG. 3, the DC power source for the protective circuit 28 may be provided by the AC power source for the heating element (or elements 16 and 16' in the case of a two element system as shown). A conventional two wire circuit for non-simultaneous operation of the heating elements 16 and 16' includes connection to an AC power source 37 via a conventional junction box 38 and a protective high limit switch 40. Direct control of heating element 16 is provided by a double throw thermostat 41 and, similarly, control of heating element 16' is effected by single throw thermostat 42, all in a conventional manner well known in the art. A transformer 43 is connected by suitable primary leads 44 to the AC power source. Secondary leads 45 from the step down transformer 43 are connected via a conventional four diode bridge 46 to provide a rectified DC current to the circuit 28 which is identical to that shown in FIGS. 1 and 2. Various modes of carrying out the present invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.	The adverse effects of the exposed metal jacket on a heating element in an electric water heater on the life and performance of a protective anode are eliminated or substantially reduced with the system that imposes a low voltage differential between the heating element jacket and the tank wall while simultaneously providing a low resistance current path which will provide a direct coductive path between the jacket and tank wall (at ground) in the event of an overvoltage condition. The system includes a potentiometer control which may be adjusted to provide the appropriate low voltage differential sufficient to substantially reduce the anode current. The relatively low resistance path allows an overvoltage current to pass readily to ground.	2
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrophobic cationic dye suitable for image formation by sublimation thermal transfer recording and a thermal transfer ink ribbon using the same. 2. Description of the Prior Art Hitherto, sublimation thermal transfer recording has been carried out to obtain high gradation full color hard copies from image information such as video or computer graphics. In the sublimation thermal transfer recording, the image recording has been performed by using a thermal transfer ink ribbon in which an ink layer having a sublimation dye or thermal diffusion dye dispersed in a hydrophobic polymer binder is formed on a polyester substrate, and a photographic paper in which a dye receiving layer comprising a hydrophobic polymer is formed on a synthetic paper substrate. More specifically, the ink layer of the ink ribbon is superimposed on the dye receiving layer of the photographic paper, and heat is applied on the polyester substrate of the ink ribbon by a thermal head or the like in accordance with an image signal, whereby migrating the dye in the ink layer to the dye receiving layer of the photographic paper to form an image. As the dye used in thermal transfer ink ribbons for such sublimation thermal transfer recording, disperse dyes have generally been used taking the dispersibility in the hydrophobic polymer binder in the ink layer; however, it has recently been proposed to employ hydrophobic cationic dyes having more excellent sensitivity in the transfer, hue of images and light resistance than the disperse dyes (Japanese Patent Application Laying-open No. 6-40172). In the patent application, it has been proposed to use diazacarbocyanine hydrophobic cationic dyes for yellow color, oxazine hydrophobic cationic dyes for cyan color, and hemicyanine hydrophobic cationic dyes for magenta color (Japanese Patent Application Laying-open No. 6-40172). However, the hemicyanine hydrophobic cationic dyes for magenta color have a problem of insufficient light resistance and transfer concentration. An attempt has been done to use a laurylsulfate salt of C.I. Basic Red 22 represented by the formula (2): which is one of diazahemicyanine hydrophobic cationic dyes having more excellent properties such as light resistance and transfer concentration than hemicyanine hydrophobic cationic dyes, as a dye for magenta color. OBJECT AND SUMMARY OF THE INVENTION However, when full color sublimation thermal transfer recording is effected with a thermal transfer ink ribbon using the laurylsulfate salt of C.I. Basic Red 22 represented by the formula (2) as a dye for magenta color, there is a problem of color reproducibility. Thus, the resulting image has a different color tone from the intended full color image since the dye of formula (2) has a yellowish red hue, that is, maximum absorption wave length (λmax) being 520 nm. The present invention will solve such problems of prior art and has an object of providing a novel diazahemicyanine hydrophobic cationic dye having a good light resistance and a good reddish purple (magenta) hue with a low proportion of other colors mixed. The present inventor has found that a diazahemicyanine hydrophobic cationic dye having a specific combination of substituents exhibits a better reddish purple (magenta) color hue and more excellent light resistance as compared with the laurylsulfate salt of C.I. Basic Red 22 and completed the present invention. Thus, the present invention provides a diazahemicyanine hydrophobic cationic dye represented by the formula (1): wherein R 1 , R 2 , R 3 and R 4 are lower alkyl groups, such as those having not more than 5 carbon atoms, R 5 is a lower alkyl group, such as one having not more than 5 carbon atoms, or a lower alkoxy lower alkyl group, such as one having not more than 6 carbon atoms, and Z - is a counter ion having a hydrophobic organic group. The present invention also provides a thermal transfer ink ribbon having a substrate and an ink layer laminated thereon wherein said ink layer contains the diazahemicyanine hydrophobic cationic dye represented by the formula (1). The diazahemicyanine hydrophobic cationic dyes of the present invention will be hereinafter described in detail. The diazahemicyanine hydrophobic cationic dyes of the present invention have a maximum absorption wave length near 540 nm and a purer reddish purple (magenta) color hue than the yellowish red hue of the laurylsulfate salt of C.I. Basic Red 22. Accordingly, the use of these hydrophobic cationic dyes in sublimation thermal transfer recording enables the formation of full color images with good color reproducibility. Further, the hydrophobic cationic dyes have a lower alkyl group linked to the phenylene group and, therefore, have an improved light resistance. In the formula (1), a preferred combination of R 1 , R 2 , R 3 , R 4 and R 5 may be such that R 1 , R 2 and R 3 are methyl groups, R 4 is an ethyl or butyl group, and R 5 is an ethyl, ethoxyethyl or butoxyethyl group. The hydrophobic organic groups of the counter ions having a hydrophobic organic group, Z - in the formula (1), may include higher alkyl groups, such as lauryl group, and aralkyl or alkylaryl groups such as dodecylphenyl group. The ion sites of the counter ions may include sulfate, sulphonate and succinate anions. Preferred examples of the counter ions having a hydrophobic organic group, Z - , include lauryl sulfate, dodecylbenzene sulphonate, diethylhexyl sulphosuccinate and dodecylsulphonate anions. In the formula (1), R 1 and R 2 are linked to the triazole ring at 1- and 4-positions, 2- and 4-positions, or 1- and 4-positions, preferably at 2- and 4-positions since light absorption of the dye can be shifted to longer wave lengths. Methods for the preparation of the diazahemicyanine hydrophobic cationic dyes of the present invention will be described with reference to the reaction scheme as shown below wherein R 1 , R 2 , R 3 , R 4 , R 5 and Z - are defined above for the formula (1). 3-Aminotriazole of the formula (a) is diazotized to prepare the diazonium salt of the formula (b). The diazotization may be carried out in a conventional manner. For example, sodium nitrite may be reacted with the 3-aminotriazole of the formula (2) under ice cooling in an aqueous sulfuric acid solution. The diazonium salt of the formula (b) is then coupled with an aniline derivative of the formula (c) under ice cooling. After the reaction, the reaction mixture is poured into water and the pH of the aqueous phase is neutralized, yielding an azo dye of the formula (d). The azo dye of the formula (d) is fractionated and dried, and then alkylated with a lower alkyl sulfate ((R 1 ) 2 SO 4 and (R 2 ) 2 SO 4 ) in a non-aqueous solvent to yield a diazahemicyanine hydrophilic cationic dye of the formula (e). R 1 and R 2 herein may be same or different. Finally, the diazahemicyanine hydrophilic cationic dye of the formula (e) is reacted with a salt Z - M + wherein M is preferably an alkali metal such as sodium to replace the counter ion with the hydrophobic Z - . Thus, there is obtained a diazahemicyanine hydrophobic cationic dye of the formula (1). The thermal transfer ink ribbon using the diazahemicyanine hydrophilic cationic dye according to the present invention will be described. The thermal transfer ink ribbon of the present invention is composed of a substrate 1 and an ink layer 2 laminated thereon as shown in FIG. 1. A heat resistant lubricating layer 3 may be provided on the back side of the substrate 1 (FIG. 2). The ink layer 2 contains a diazahemicyanine hydrophobic cationic dye of the formula (1) having good light resistance and hue. Therefore, the resulting image using the ink ribbon has an improved light resistance. Further, color reproducibility will be good. In the thermal transfer ink ribbon of the present invention, the substrate 1 may be any one for conventional thermal transfer ink sheets and may include, for example, resin sheets such as polyester films (e.g., PET etc.), polyimide films and polyamide films (e.g., nylons etc.); and papers such as condenser and glassine papers. Usually, the thickness of the substrate may preferably be 3 to 20 μm. The ink layer comprises the diazahemicyanine hydrophobic cationic dye of the formula (1) dispersed in a binder resin. Too low contents thereof in the ink layer 2 can not result in sufficient image concentrations while too much reduces the film forming property of the ink layer 2. Usually, the content is preferably 1 to 70% by weight of the ink layer 2. The binder in the ink layer 2 may be any of binders conventionally used in ink layers of sublimation thermal transfer ink ribbons and may include, for example, butyral resins, polyvinyl alkyl acetal resins, cellulose ester resins, cellulose ether resins, urethane resins, polyester resins and polyvinyl acetate resins. Usually, the thickness of the ink layer 2 is preferably 0.5 to 5.0 μm. Further, the ink layer 2 may optionally contain, for example, a plasticizer, solvent, caking agent. The heat resistant lubricating layer 3 may be the same as one used in conventional sublimation thermal transfer ink ribbons. The thermal transfer ink ribbon of the present invention may be prepared in any conventional manner. For example, the ink ribbon of FIG. 2 may be prepared by coating a heat resistant lubricating layer-forming coating material on the back side of the substrate to form a heat resistant lubricating layer, coating an ink layer-forming coating material containing the diazahemicyanine hydrophobic cationic dye on the opposite side of the substrate, and drying to form an ink layer. The thus obtained thermal transfer ink ribbon can be well applied to the conventional sublimation thermal transfer recording devices. The diazahemicyanine hydrophobic cationic dyes of the present invention exhibit a good light resistance and color hue. Accordingly, a thermal transfer ink ribbon using the dye as a magenta dye can form an image having a good light resistance and color reproducibility. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross sectional view of the thermal transfer ink ribbon of the present invention. FIG. 2 is a cross sectional view of the thermal transfer ink ribbon of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be illustrated by way of examples. Inventive Example 1 In a solution of 20 g of sulfuric acid in 50 ml of water, 8.4 g of 3-amino-1,2,4-triazole was dissolved. While the solution was maintained at -2° to 0° C., 8.5 g of sodium nitrite was added thereinto. Diazotization reaction was effected for 3 hours. After the diazotization reaction was completed, 16 g of N,N-diethyl-m-toluidine was added to the reaction mixture at the same temperature and coupling reaction was effected for 6 hours. After the reaction was completed, the reaction mixture was poured into 500 g of ice and the pH of the aqueous phase was adjusted with an aqueous sodium hydroxide solution to 6 to 7 to precipitate an azo dye. The precipitated azo dye was filtered out and dried. The dye was dissolved in 300 ml of monochlorobenzene. To this solution 40 g of dimethyl sulfuric acid was dropwise added at a reaction temperature of 90° to 95° C. to dimethylate and cationize the azo dye. The released resulting cationic dye was fractionated by decantation and washed with a small amount of toluene to yield 36 g of a diazahemicyanine hydrophilic cationic dye. The resultant cationic dye was dissolved in 700 ml of water and an aqueous solution of 36 g of sodium lauryl sulfate in 300 ml of water was added. Thus, the cationic dye was hydrophobitized to precipitate and the resulting dye was fractionated and dried to yield 48 g of a diazahemicyanine hydrophobic cationic dye represented by the formula (3): The hydrophobic cationic dye had a maximum absorption wave length (λmax) of 538.6 nm (methanol) and exhibited a good reddish purple (magenta) hue. Inventive Example 2 The procedures of Inventive Example 1 were repeated except that N,N-diethyl-m-toluidine was replaced with 20.7 g of N-ethoxyethyl-N-ethyl-m-toluidine to yield 53 g of a diazahemicyanine hydrophobic cationic dye represented by the formula (4): The hydrophobic cationic dye had a maximum absorption wave length (λmax) of 540 nm (methanol) and exhibited a good reddish purple (magenta) hue. Inventive Example 3 The procedures of Inventive Example 1 were repeated except that N,N-diethyl-m-toluidine was replaced with 23.5 g of N-ethoxyethyl-N-butyl-m-toluidine and 36 g of sodium lauryl sulfate was replaced with 35 g of sodium dodecyl benzene sulphonate to yield 61 g of a diazahemicyanine hydrophobic cationic dye represented by the formula (5): The hydrophobic cationic dye had a maximum absorption wave length (λmax) of 539.4 nm (methanol) and exhibited a good reddish purple (magenta) hue. Inventive Example 4 The procedures of Inventive Example 1 were repeated except that N,N-diethyl-m-toluidine was replaced with 23.5 g of N-butoxyethyl-N-ethyl-m-toluidine to yield 56 g of a diazahemicyanine hydrophobic cationic dye represented by the formula (6): The hydrophobic cationic dye had a maximum absorption wave length (λmax) of 540.3 nm (methanol) and exhibited a good reddish purple (magenta) hue. Inventive Examples 5 to 8 and Comparative Example 1 The hydrophobic cationic dyes of the formulas (3) to (6) obtained in Inventive Examples 1 to 4 were used to prepare thermal transfer ink ribbons in the following manner. In Comparative Example 1, the hydrophobic cationic dye used was the lauryl sulfate salt of C.I. Basic Red 22 of the formula (2). (Preparation of thermal transfer ink ribbons) Thermal transfer ink ribbons were prepared by coating a composition for forming an ink layer as shown in Table 1 with a wire bar coater on one side of a polyethylene terephthalate (PET) film substrate of 6 μm in thickness having a heat resistant lubricating layer provided on the opposite side so that the dry thickness of the ink layer was 1 μm. TABLE 1______________________________________Composition for forming ink layer Amount formulatedComponent (part by weight)______________________________________Hydrophobic cationic dye 2Inventive Example 5 Dye of formula (3)Inventive Example 6 Dye of formula (4)Inventive Example 7 Dye of formula (5)Inventive Example 8 Dye of formula (6)Comparative Example 1 Dye of formula (2)Polyvinyl butyral 2(6000-CS, DENKI KAGAKU KOGYO K.K.)Toluene 25Methyl ethyl ketone 25______________________________________ (Preparation of photographic paper) In order to test and evaluate the light resistance of images obtained by using the thermal transfer ink ribbons, photographic papers were prepared in the following manner. Photographic papers were prepared by coating a composition for forming a dye receiving layer as shown in Table 2 with a wire bar coater on the surface of a synthetic paper of 150 μm in thickness (FPG-150, Oji Yuka Gosei-shi) so that the dry thickness of the layer was 8 μm and drying at 100° C. for 60 minutes. TABLE 2______________________________________Composition for forming dye receiving layer Amount formulatedComponent (part by weight)______________________________________Vinyl chloride/vinyl acetate copolymer 100(Denka Vinyl #1000GK,DENKI KAGAKU KOGYO K.K.)Mold releasing agent 4(SF8427, TORAY DOW-CORNING CO., LTD.)Cross linking agent 5(Takenate D-110N,TAKEDA CHEMICAL INDUSTRIES LTD.)Toluene 200Methyl ethyl ketone 200______________________________________ (Evaluation) The thus obtained ink ribbon and photographic paper were applied to a color video printer (Tradename: UP-3000, Sony Corporation) and four kinds of rush printing were carried out so that an initial image density (Do) was 0.5, 1.0, 1.5 or 2.0, respectively. The ink ribbons of Inventive Examples 5 to 8 gave rush prints with a good magenta hue while an image with a yellowish red hue was obtained in Comparative Example 1. The obtained images were irradiated with a xenon arc lamp at 90,000 kJ/m 2 and the light, resistance was evaluated by calculating a percent of image remaining after irradiation. The results are shown in Table 3. The percent of remaining image was defined as a ratio of an image density (Dt) measured after the irradiation to the initial image density (Do); i.e., percent of remaining image (%)=100 Dt/Do. The higher the percent of remaining image, the better the light resistance. TABLE 3______________________________________Remaining image (%)Initial image Comparativedensity Inventive Example Example 1(Do) 5 6 7 8 1______________________________________2.0 85 85 88 85 611.5 79 83 83 83 571.0 65 82 83 74 540.5 60 70 77 77 45______________________________________ As seen from Table 3, the thermal transfer ink ribbons using the diazahemicyanine hydrophobic cationic dyes according to the present invention gave images with a better light resistance than the ink ribbon of Comparative Example 1. ##STR2##	Disclosed are diazahemicyanine hydrophobic cationic dyes represented by the formula (1): ##STR1## wherein R 1 , R 2 , R 3 and R 4 are lower alkyl groups having not more than 5 carbon atoms, R 5 is a lower alkyl group having not more than 5 carbon atoms or a lower alkoxy lower alkyl group having not more than 6 carbon atoms, and Z - is a counter ion having a hydrophobic organic group, and a thermal transfer ink ribbon having a substrate and and ink layer laminated thereon containing said cationic dye.	8
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to systems for providing indications of hazardous conditions to aircraft and, more particularly but not by way of limitation, to systems that provide indications of the proximity of helicopters to obstructions. 2. Brief Description of the Prior Art. In recent years, helicopters have increasingly come to be used in circumstances in which a helicopter is flown near an obstruction under conditions that provide the pilot with only limited visibility. For example, hovering helicopters have been used to rescue people from roofs of burning buildings so that visibility can be limited by smoke while the helicopter is flown near air conditioning and elevator equipment that is often located on a rooftop. Similarly, and again in rescue situations, a helicopter might be flown near buildings, cliffs and the like under inclement weather conditions. Additionally, dust can be thrown up by the downdraft of a helicopter's rotors while the helicopter is maneuvering near objects on the ground. In these circumstances, a severe hazard exists that the helicopter rotors, which, because of their rotation, are difficult to see, will contact the obstruction to cause the helicopter to crash. Nor are such hazards limited to helicopters. Vertical take off and lift aircraft experience similar hazards when operated from, for example, the deck of an aircraft carrier. In this case, the wings of the aircraft may contact the carrier's island to similarly result in a crash. Unfortunately, little has been done to provide a helicopter pilot with a system that will enable him to accurately gauge the location of the rotors with respect to obstructions near which he might be maneuvering and, especially, near which he might be maneuvering under conditions of limited visibility. While it is known to mount lights in the tips of rotors, as disclosed in U.S. Pat. No. 4,066,890, so that the pilot can see the arc along which the rotor tips are moving under conditions of good visibility, no system has heretofore been developed which will enable the pilot of a helicopter not only to accurately judge the location of the rotor arc under limited visibility conditions but also provide him with a clear indication of his freedom to maneuver while he is flying near obstructions. SUMMARY OF THE INVENTION The present invention exploits the scattering of light by a cause of limited visibility, smoke, dust, rain or the like, to provide the pilot of a helicopter with an obstruction proximity indication system that indicates to the pilot not only an absolute minimum safe flying distance from the obstruction but, additionally, the distance between the minimum and nearby obstructions. To this end, the system of the present invention is comprised of at least one first light source that provides a collimated beam extending past the rotor arc and a second light source that provides a collimated beam that similarly extends past the rotor arc to intersect the light beam from the first light source at a proximity limit location that can be selected to be on a level with the rotors and displaced a selected distance radially therefrom. Since the beams are collimated, little loss of intensity will occur between the light sources and the proximity limit location so that light scattered from the cause of limited visibility will mark both the beams and their intersection to provide the pilot with the location of the limit locations at a glance from the aircraft. Additionally, the collimation of the beams serves to limit the volume of space in which the beams intersect to, consequently, restrict the sizes of the proximity limit locations and thereby enhance the definition of the aircraft location relative to obstructions. Moreover, since both beams will continue radially outwardly from the aircraft to impinge on any nearby obstruction, the pilot is further provided with the distance between the proximity limit locations and the obstructions so that he is in a position to gauge the rapidity with which a maneuver on the part of his aircraft may be safely undertaken. An important object of the present invention is to provide the pilot of an aircraft with an indication of the proximity of the aircraft to obstructions near which he may be flying. Another object of the invention is to provide a hazard warning to the pilot of an aircraft that will enable the pilot to accurately judge the freedom with which he may safely maneuver his aircraft about obstructions near which he is flying. Still another object of the invention is to provide a system that will enable a helicopter pilot to safely maneuver his aircraft near obstructions under conditions of limited visibility. A further object of the invention is to provide an obstruction proximity indicator for helicopter pilots that is reliable, economical to manufacture and economical to install. Other objects, features and advantages of the present invention will become apparent from the following detailed description when read in conjunction with the drawings and appended claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of an aircraft; specifically, a helicopter equipped with a proximity indication system constructed in accordance with the present invention. FIG. 2 is an isometric view, in partial cross-section, of a first light source used in the proximity indication system. FIG. 3 is an isometric view, in partial cross-section, of a second light source used in the proximity indication system. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings in general, and more particularly to FIG. 1, shown therein and designated by the general reference numeral 10 is an aircraft equipped with an obstruction proximity indication system (not generally designated in the drawings) constructed in accordance with the present invention. For purposes of this disclosure, the aircraft 10 has been illustrated as a helicopter but no limitation as to particular aircraft type is intended by such illustration. Rather, the invention can be used with any type of aircraft; for example, a vertical takeoff and land aircraft, that can be expected to be operated near stationary objects, as indicated at 12 in FIG. 1, in carrying out normal functions of the aircraft. In general, the obstruction proximity indication system is comprised of a plurality of first light sources 14 that are mounted on a fuselage 16 of the aircraft 10 to project collimated beams of light 17, as will be discussed below, outwardly of the aircraft 10 to pass through selected proximity limit locations 18 that are disposed exteriorly to all portions of the aircraft. In particular, in the case in which the aircraft 10 is a helicopter, the first light sources 14 are preferably mounted on upper portions of the fuselage 16 and angled slightly upwardly to place the proximity limit locations on a level with a path of travel 20 of a helicopter rotor 22 and a selected distance 24 radially outwardly of the path 20 to indicate, as will be discussed below, a minimum clearance between the rotors 22 and obstructions, such as the obstruction 12, at which the aircraft 10 can be safely operated. A typical value for the distance 24 that will provide a suitable safety factor against drift of the aircraft and movement caused by winds is approximately five feet. In addition to the first light sources 14, the obstruction proximity indication system is further comprised of a plurality of second light sources 26, equal in number to the first light sources 14, that are mounted on lower portions of the fuselage 16 and aimed thereon to project collimated beams of light 28 through the proximity limit locations 18. As indicated in FIG. 1, each second light source 26 is paired with a selected first light source 14, which is located directly above the second light source 26, so that two collimated light beams, one from upper portions of the fuselage 16 and one from lower portions of the fuselage 16, intersect at each proximity limit location 18. The manner in which the first light sources 14 are constructed to provide the collimated beams 17 has been illustrated in FIG. 2 to which attention is now invited. As shown therein, each first light source 14 is comprised of a concave reflector 30 having a flange 32 by means of which the light source 14 can be secured within a well in the aircraft fuselage 16 or a suitable housing mounted on the fuselage 16 in a conventional manner. Within the reflector 30, and at the focal point thereof, the light source 14 is further comprised of a conventionally mounted lamp 33 so that light emitted by the lamp 33 and reflected from the reflector 30 emerges as a collimated beam as indicated at 17 in FIG. 2. A hemispherical shield 36, constructed of a plastic material, is mounted over the open end of the reflector 30 and held in place by a guard ring 38 that is secured to the flange 32 in any convenient manner. In the preferred form of the invention, the first light sources 14 are constructed to provide, in addition to the collimated beams 17, diverging beams of light 40, indicated in dot-dash lines in FIGS. 1 and 2, that are coaxial to the collimated beams 17. To this end, a concavity 42 is formed in central portions of the shield 36 to provide a negative lens that is aligned with the axis of the collimated beam 17. As shown in FIG. 2, the concavity 42 has a small diameter compared to the diameter of the reflector 30 so that, in combination with the divergence of the beam 40, the intensity of the beam 40 in the vicinity of the proximity limit locations will be considerably lower than the intensity of the collimated beams 17 and 28 of the first and second light sources 14 and 26 so that the beams 40 will not interfere with the visibility of light scattered from the proximity limit locations by; for example, dust thrown up by the downwash of the rotor 22. As shown in FIG. 1, the divergent beam 40 illuminates a large area of the obstruction 12 to permit the pilot of the aircraft to accurately determine the separation between the obstruction 12 and the safe limit of approach defined by the proximity limit location so that he can adjust the degree and rate of maneuvers he performs to insure that the rotor 22 always remains separated from the obstruction 12. The second light sources 26 (see FIG. 3) are constructed similarly to the first light sources 14. As shown therein, each second light source 28 comprises a concave reflector 44, having a mounting flange 46 used to mount the reflector 44 on the aircraft 10, a lamp 48 at the focus of the reflector 44, and a transparent shield 50. The transparent shield 50 extends over the open end of the reflector 44 and is held in place by a guard ring 52. In the light source 26, the reflector 44 is positioned to have an axis of cylindrical symmetry that is directed toward the proximity limit location corresponded to be defined by the second light source 26 and its associated first light source 14 so that the reflector 44 directs the collimated light beam 28 through the shield 50 toward such proximity limit location. In the second light source 26, the shield 50 has the form of a plate with an axially extending flange cut at an angle to the plate and, like the shield 36, is preferably constructed of a plastic material. As in the case of the shield 36 of the first light source 14, the shield 50 is provided with a small central concavity 56 that provides a low intensity diverging beam 58 (shown in dotdash lines in FIG. 1) coaxial to the collimated beam 28. As will be clear from the above description of the first and second light sources 14 and 26, the collimation of the light beams 17 and 28 will limit losses in intensity for such beams from the first and second light sources 14 and 26 to the proximity limit locations to enhance the visibility of light scattered from such locations. Such visibility can be further enhanced by selecting high intensity halogen lamps for the lamps 33 and 48 and the geometric limits of the proximity limit locations are, in the preferred embodiment of the invention, distinguished from the collimated beams 17 and 28 by projecting the beams 17 and 28 in different colors; that is, the use of different colors for the beams 17 and 28 will give rise to qualitative differences across the boundaries between each beam 17 and 28 and the sum of the two beams. Thus, the pilot of the aircraft will be able to determine the positions of the proximity limit locations 18 by merely glancing through the windshields of the aircraft. The difference in colors can be conveniently effected by using lamps 33 and 48 of different colors or by tinting the shields 36 and 50. Operation of the Preferred Embodiment In use, the obstruction proximity indication system is mounted on an aircraft such as the helicopter 10 shown in FIG. 1 and discussed above. The first and second light sources 14 and 26 of the obstruction proximity indication system are connected, via suitable switches, to the helicopter electrical system, preferably in a circuit separate from other lighting systems of the aircraft to prevent mishaps to one light system from affecting the other system. Thus, should either the conventional lighting system of the aircraft or the obstruction proximity indication system malfunction during an operation in which the aircraft is operating near a stationary object, the other system can, in many cases, be used to gauge the position of the object sufficiently to remove the aircraft from the scene. The separate wiring of the obstruction proximity indication system provides an additional safety factor for the pilot of the aircraft. When the aircraft is called upon to perform some operation near a stationary object, for example the rescue of persons from a burning building, the first and second light sources 14 and 26 are activated as the aircraft nears the stationary object so that the pilot can observe the minimum distance that he can approach the object. At times when the pilot is a large distance from the object, he will observe a large distance between the proximity limit locations and the object and can, accordingly, engage in maneuvers that will rapidly bring him to a desired location with respect to stationary objects with which the operation is concerned. On the other hand, should the positioning of the aircraft bring him near a stationary object, the pilot can readily gauge the distance between the object and the proximity limit locations and utilize appropriately small corrections to his position that will eliminate any possibility of inadvertently making a large shift in position that might bring a portion of the aircraft, such as the rotors 22 of the helicopter 10, into contact with the stationary object 12. It will be clear that the present invention is well adapted to carry out the objects and attain the ends and advantages mentioned as well as those inherent therein. While a presently preferred embodiment has been described for purposes of this disclosure, numerous changes may be made which will readily suggest themselves to those skilled in the art and which are encompassed in the spirit of the invention disclosed and as defined in the appended claims.	Visually observable safe limits for the proximity of an aircraft, such as a helicopter, to obstructions are provided by pairs of lights which provide collimated beams intersecting at limit points located radially outwardly of the arc of the helicopter rotor blades so that light scattered from the intersecting beams at the limit points provides the helicopter pilot with visual references of the rotor arc. Each light of each pair has a concave reflector and a lamp at the focal point of the reflector to provide the collimated beams and transparent plastic shields over the open ends of the reflectors have concavities in central portions to provide diverging beams that illuminate the obstructions.	1
TECHNICAL FIELD This invention relates to a surgical trocar and more particularly to a safety trocar in which the sharp cutting tip retracts into the cannula so as to minimize the likelihood of inadvertent injury to viscera and other internal tissue. DESCRIPTION OF THE PRIOR ART Trocars are sharp pointed surgical instruments used to puncture a body cavity. Trocars are generally adapted to be used together with a tubular trocar sleeve or cannula. Once the body cavity has been punctured by the trocar, the sharp trocar is removed from the cannula, thereby leaving the cannula extending into the body cavity. Endoscopic surgical procedures are then performed through the cannula with accessory instrumentation such as laparoscopes, dissectors, graspers, etc. Commercially available safety trocars include a spring-loaded safety shield which is adapted to cover the trocars tip once the body cavity has been entered so as to provide an increased level of protection to internal structures from puncture of laceration. For example, U.S. Pat. No. 4,601,710 to Moll describes a trocar assembly which consists of two subassemblies: a trocar subassembly which includes a sharp-tipped trocar and a spring-loaded tubular safety shield positioned therearound, and a cannula subassembly. When ready for use, the trocar and safety shield of the trocar subassembly are inserted through the cannula. The safety shield is initially in its distal-most position covering the trocar tip. Exertion of pressure against the skin with the trocar causes the shield to be pushed rearwardly against the spring to expose the piercing tip of the trocar. The tip penetrates the skin and underlying tissue with continued pressure. Once the tip has penetrated through the wall and has entered the cavity, the force against the front end of the shield ceases and the shield is automatically moved back to its distally extended position. Viscera and other internal tissue are thus protected from contact with the sharp piercing tip and potential damage therefrom. An article entitled "Needle for the Puncture and Lavage of the Abdominal Cavity" authored by F. S. Subairov discloses a safety device for puncturing the abdominal cavity which consists of a hollow tube, a stylet and a spring. The spring is soldered to the stylet and threaded into the rear of the hollow tube. The distal end of the stylet is exposed from the hollow tube by pressing the stylet toward the tube, thereby compressing the spring. Once the stylet and tube enter a body cavity, the tube is advanced under spring force to cover the distal end of the stylet. A similar device is disclosed in EP 350,291 (see FIGS. 1-4). U.S. Pat. No. 4,535,773 to Yoon suggests several alternative safety trocar designs. In one embodiment (see FIGS. 22-28), a spring-loaded blunt probe is provided within the trocar shaft, as with conventional Verres needles. The blunt probe is adapted to reciprocally slide through an aperture in the trocar tip such that when the trocar tip enters a body cavity, the blunt probe springs distally forward through the aperture to prevent contact between the trocar tip and body organs. In a second embodiment (see FIGS. 33-36), pressure sensors or transducers are fitted into the trocar blade surfaces and the distal end of the cannula. Sets of electrical leads run through the trocar shaft and communicate with an alarm network in the proximal portion of the device. A further modification is suggested in which the trocar shaft is initially manually extended and maintained in its extended position by a detent which protrudes through a hole in the surrounding tubular structure. The hole aligns with a solenoid socket. When the instrument is fully assembled and the trocar tip is forced through a body wall, the electrical leads running through the trocar shaft send electrical signals to the solenoid which, at the appropriate instant, forces the detent from the hole, allowing the trocar tip to withdraw into the cannula. Additional mechanisms for effecting withdrawal of cutting implements are also known. See, e.g., U.S. Pat. Nos. 4,375,815 to Burns; 3,657,812 to Lee; and 3,030,959 to Grunert. SUMMARY OF THE INVENTION It has now been found that an improved safety trocar may be provided which includes: (a) a cannula assembly comprising a cannula and a cannula housing; (b) a trocar assembly comprising a sharp trocar tip, an obturator shaft, and a trocar housing; (c) means associated with the obturator shaft which releasably maintains the trocar tip in an extended position; (d) means associated with the cannula assembly for releasing the releasable obturator means; and (e) biasing means for retracting the trocar tip from the extended position to a retracted position in response to release of the releasable obturator means. The safety trocar of the present invention is adapted to be armed by the surgeon immediately prior to use. Arming may be accomplished by advancing a button which extends through the trocar housing, by compressing the trocar housing toward the cannula housing, or by like means. Once armed, the trocar tip releasably protrudes beyond the distal end of the cannula. As the surgeon presses the trocar, and more particularly the trocar tip, against the body wall of a patient, an incision into and through the body wall is begun. With continued pressure by the surgeon, the distal end of the cannula comes into contact with the body wall. The initial counterforce exerted by the body wall against the cannula causes a mechanism associated with the cannula to position the obturator shaft (together with the cutting tip) for immediate retraction upon entry of distal end of the cannula into the body cavity. Thus, removal of the counterforce from the distal end of the cannula, e.g., upon entering the body cavity, results in immediate and automatic withdrawal of the trocar tip into the cannula under the force of a biasing means, e.g., a spring. In a preferred embodiment of the trocar, a latch is associated with the obturator shaft to which the trocar tip is mounted, the latch being biased radially outward and being adapted to engage an internal shelf formed in the cannula when the trocar is armed. The cannula is reciprocally mounted to the cannula housing and biased, e.g., by a compression spring, distally relative to the cannula housing. As the trocar tip enters the body cavity and the body wall exerts force on the distal end of the cannula, the cannula reciprocates proximally into the cannula housing. This cannula reciprocation repositions the cannula's internal shelf relative to the latch such that, upon distal movement of the cannula upon entry into the body cavity, the latch is released from engagement with the internal shelf. A spring which was loaded upon arming the trocar is thus free to immediately retract the trocar tip into the cannula. In a particularly preferred trocar embodiment, abutment means are provided on the exterior of the cannula toward its distal end to facilitate reciprocation thereof through contact with the body wall. The trocar of the invention is also designed to permit manual retraction or disarming of the cutting tip, if so desired. This is accomplished by manually reciprocating the cannula housing and releasing, thereby disengaging the latch from the internal shelf. The trocar is also typically provided with an indicator which signals the surgeon as to whether the trocar is armed or disarmed. For example, the relative position of the button used to arm the trocar may be calibrated or indexed to communicate the trocar tip position or a window may be provided through which a trocar tip position indicator is visible. The trocar of the present invention provides a safe and efficacious means for gaining access to body cavities to permit minimally-invasive diagnostic and surgical procedures to be accomplished. The trocar is equipped with a reliable mechanism for effectuating immediate, automatic retraction of the cutting tip into the cannula. Penetration force is kept to a minimum through the unique internal mechanism for releasably maintaining the trocar tip in the armed position. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings in which: FIG. 1 is a side view of a trocar of the present invention in an armed configuration; FIG. 2 is a top view of the trocar assembly of FIG. 1, partially in cross section; FIG. 3 is an exploded view of a spring assembly; FIG. 4 is a front view of a top trocar housing; FIGS. 5 and 6 are plan and side views, respectively, of a spring-retaining plate; FIGS. 7 and 8 are partial side views of the cannula; FIG. 9 is a plan view of a lower cannula housing; FIG. 10 is a sectional side view of the cannula housing of FIG. 9 taken along line 10--10; FIG. 11 is a bottom view of a trocar housing; FIG. 12 is a side view of a shelf insert; FIG. 13 is a front view of the shelf insert of FIG. 12; FIG. 14 is a side view of a latch; FIG. 15 is a side view of a latch release finger; FIG. 16 is a side view, partially in section, of a portion of a cannula; FIG. 17 is a side view of a latch subassembly. FIG. 18 is a top view, partially in section, of the proximal end of an unarmed trocar of the present invention; and FIGS. 19-21 are top views, partially in section, of the proximal end of an armed trocar of the present invention showing a sequence of positions which culminate in retraction of the trocar tip. DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 1, trocar 10 is shown in its fully assembled condition with cutting tip 12 extending from cannula 14. Trocar 10 includes a trocar assembly 16 and a cannula assembly 18. The longitudinally extending or endoscopic portion of trocar assembly 16 which extends from trocar housing 20 is shielded from view in FIG. 1 by cannula housing 21 and cannula 14, except for extended cutting tip 12. A circumferential abutment surface 15 is provided toward the distal end of cannula 14. Referring now to FIGS. 2 and 3, pyramidal cutting tip 12 is rotatably mounted to obturator shaft 22 at swivel joint 24. A cylindrical channel 26 is formed in the proximal end of obturator shaft 22. A tension spring 28 (see FIGS. 1 and 3) is positioned within channel 26 and anchored to obturator shaft 22 at distal extension 30 by pin 32. An anchor pin 34 which is adapted to mount to rear wall 36 of trocar housing 20 includes an aperture 35 which cooperates with proximal arm 37 to anchor tension spring 28 to trocar housing 20. A flange 38 is formed at the proximal end of obturator shaft 22 encircling tension spring 28. Flange 38 forms a half-moon shaped button 40 which slides within slot 42 in the upper face 44 of trocar housing 20. Movement of button 40 within slot 42 moves obturator shaft 22 and cutting tip 12 relative to trocar housing 20. Tension spring 28 biases obturator shaft 22 and its accompanying structure proximally, such that flange 38 rests against rear face 46 of slot 42 absent external influences. Referring to FIG. 4, top housing 48 of trocar housing 20 is shown. Top housing 48 includes mounting legs 50 for attachment to a bottom housing 90 (FIG. 11). Upper face 44 includes a concave region 52 in the base of which is formed slot 42. As most clearly seen in FIG. 1, button 40 is sized and dimensioned to conform to and slide within concave region 52 while extending slightly above upper face 44 of trocar housing 20. The cooperation between concave region 52 and button 40 facilitates unimpeded movement of button 40, particularly upon retraction of trocar tip 12 as discussed below, without sacrificing convenient thumb access to button 40 for arming of trocar 10 by the surgeon. Turning to cannula assembly 18, cannula 14 defines a tubular lumen and is reciprocally mounted to cannula housing 21. Referring to FIGS. 2 and 5-8, a spring-retaining plate 54 is mounted to flange 56 at the proximal end of cannula 14, e.g., by adhesive or welding, with central aperture 58 in plate 54 aligned with the lumen through cannula 14. Aperture 58 is sized to accommodate unencumbered passage of obturator shaft 22 and includes oppositely directed extension arms 62, each arm 62 having an aperture 64. Apertures 64 receive and frictionally engage cylindrical pins 66. Aperture extension 60 is formed in one extension arm 62 allowing passage of latch subassembly 147 therethrough, as described below. Referring again to FIG. 2, cannula housing 21 receives spring-retaining plate 54 with cylindrical pins 66 facing proximally. Compression springs 68 are positioned against extension arms 62 and around pins 66. Pins 66 thus act to position and support springs 68. Chambers 70 are formed in cannula housing 21 to receive and capture the opposite ends of compression springs 68. Reciprocation of cannula 14 into cannula housing 21 causes proximal movement of plate 54 which compresses springs 68 within chambers 70, thereby biasing cannula 14 in the distal direction. Returning to FIGS. 7 and 8, the proximal end of cannula 14 includes two slots 72 and 74, preferably separated by at least 90°. Alignment slot 72 serves to maintain rotational alignment of cannula 14 with respect to cannula housing 21. Referring additionally to FIGS. 9 and 10, alignment pin 76 is fixedly secured within aperture 78 in lower cannula housing 80 and, when fully inserted into housing 80, extends into lumen 82. In assembling cannula 14 within lower cannula housing 80, alignment pin 76 is positioned within alignment slot 72, thereby preventing rotation of cannula 14 yet permitting axial movement of cannula 14 relative to cannula housing 21. Additionally, inwardly directed orientation pin 84 on proximal housing extension face 86 cooperates with an orientation slot 88 in bottom housing 90 (see FIG. 11) to ensure proper alignment between cannula housing 21 and trocar housing 20. A gasket 92 and stabilizer plate 96 are positioned within flange 94 in lower cannula housing 80 to provide a gas seal with inserted instrumentation, and to cooperate with an internal flapper valve, as is known in the art. Slot 74 in cannula 14 forms an internal shelf 98 with which latch 100 (see FIG. 14) is adapted to engage. Internal shelf insert 102 (FIGS. 12 and 13) is positional within cavity 104 in lower cannula housing. Shelf insert 102 comprises angled latching faces 106, bridging arm 108 and longitudinal slot 110. Shelf insert 102 is positioned within cavity 104 such that angled latching faces 106 are directed distally and edges 112 are substantially aligned with internal shelf 98 of cannula 14. Bridging arm 108 abuts outer wall 114 of cavity 104 and is typically secured thereto, e.g., by an adhesive. Latch 100 has a body 116 which forms a latch finger 118 which includes an outer camming face 120 and an inner latching face 122. Aperture 124 is located in mid-region 117 of body 116 and permits latch 100 to be movably joined to latch release finger 126 (see FIGS. 15 and 17). Mid-region 117 is of reduced thickness relative to the remainder of body 116 to accommodate latch release finger 126. Aperture 128 is formed in the region of body 116 distant from latch finger 118. Latch release finger 126 includes a substantially triangularly-shaped extension 138 having distal and proximal cam faces 140 and 142, respectively. Latch release finger 126 also includes an aperture 144 and a spring abutment region 145. As shown in FIG. 16, latch release finger 126 is movably mounted to latch 100 by means of a pin (not pictured) which passes through apertures 144 and 124 to form a latch subassembly 147. When release finger 126 is positioned such that extension 138 is directed toward aperture 128, abutment region 145 extends below latch wall 148. Latch subassembly 147 is pivotally joined to obturator shaft 22 by a pin (not pictured) which passes through aperture 128 in latch body 116 and aperture 132 in hollow region 130 of shaft 22. As shown in FIG. 16, a leaf spring 134 is mounted to shelf 136 in hollow region 130, e.g., by an adhesive. The proximal region 146 of leaf spring 134 biases latch 100 clockwise around aperture 128 and biases release finger 126 counter-clockwise relative to aperture 144. Hollow region 130 is sized and dimensioned to permit latch subassembly 147 to be fully recessed therewithin (against the bias of leaf spring 134). Inasmuch as release finger 126 is restricted in its counter-clockwise rotation by latch finger 118 and/or abutment with wall 119, and in its clockwise rotation by engagement between spring abutment region 145 and leaf spring 134, the full range of rotation of release finger 126 is approximately 90°. In use, and referring generally to FIGS. 18-21 cutting tip 12 and obturator shaft 22 are introduced through cannula housing 21 and into cannula 14. When obturator shaft 22 is fully inserted, trocar housing 16 abuts cannula housing 21. However, cutting tip 21 remains within cannula 14 until trocar 10 is armed by the surgeon. To arm the instrument, the surgeon advances button 40 within channel 42 which distally advances obturator shaft 22 and causes cutting tip 12 to extend beyond cannula 14. Distal movement of obturator shaft 22 also results in distal movement of latch subassembly 147. Leaf spring 134 biases latch subassembly 147 outward from hollow region 130. As obturator shaft 22 moves distally, outwardly biased latch subassembly 147 passes through aperture extension 60 in spring-retaining plate 54. Outer camming face 120 of latch 100 then contacts flange 56 at the proximal end of cannula 14, causing counterclockwise rotation of latch subassembly 147 relative to aperture 128 (see FIG. 17). This counterclockwise rotation recesses latch subassembly 147 within hollow region 130 against the bias of leaf spring 134. As cutting tip 12 approaches its fully armed position, latch subassembly 147 comes into alignment with slot 74 in cannula 14. Outer camming face 120 is thus freed from contact with the inner surface of cannula 14, and leaf spring 134 causes latch subassembly 147 to rotate clockwise such that latch finger 118 extends radially outward from hollow region 130. However, latch release finger 126 remains positioned such that extension 138 is directed substantially toward aperture 128, with abutment region 145 resting against leaf spring 134. The freeing of camming face 120 from contact with cannula 14 is generally accompanied by an audible click, signalling the surgeon that trocar 10 is armed and further distal movement of button 40 is unnecessary. When the surgeon releases button 40, tension spring 38 draws obturator shaft 22 proximally until inner latching face 122 of latch 100 engages internal shelf 98 and shelf insert 102. Latch release finger 126 passes back within cannula 14 proximal of slot 74, thereby pressing abutment region 145 against the bias of leaf spring 134. In this fully armed position of FIGS. 1 and 2, cutting tip 12 extends beyond cannula 14 and button 40 is distally located within slot 42. The surgeon presses armed trocar 10 against the body wall of a patient, thus causing piercing tip 12 to incise the tissue. As cutting tip 12 passes through the body wall, the distal end of cannula 14 is brought into engagement with tissue. The counterforce exerted by the body wall against cannula 14 and abutment surface 15 causes cannula 14 to move proximally against the bias of compression springs 68. This proximal movement of cannula 14 release latch release finger 126 to enter slot 74. Latch release finger 126 rotates counterclockwise relative to aperture 144 within longitudinal slot 110 in shelf insert 102. As the surgeon continues to press trocar 10 against the body wall, piercing tip 12 enters the body cavity. Continued pressure by the surgeon advances cannula 14 into the body cavity as well. As soon as the counterforce of the body wall against the distal end of the cannula 14 and abutment surface 15 is surpassed by the distally-directed force of compression springs 68 against spring-retaining plate 54, cannula 14 is driven distally relative to cannula housing 18. As cannula 14 moves distally, internal shelf 98 contacts proximal cam face 142 of latch release finger 126. Latch release finger 126 is thus driven counterclockwise such that extension 138 abuts latch finger 118 and/or the body of latch release finger 126 abuts wall 119 of latch 100. In this position, latch release finger 126 prevents engagement between internal shelf 98 and latch finger 118. As cannula 14 continues to move distally, internal shelf 98 cams latch subassembly 147 counterclockwise relative to aperture 128 against the bias of leaf spring 134, thus freeing latch finger 118 from engagement with shelf insert 102. As soon as the tip of latch finger 118 rotates out of engagement with shelf insert 102, tension spring 28 draws obturator shaft 22 and cutting tip 12 proximally such that cutting tip 12 is positioned within cannula 14. Button 40 is also drawn proximally within slot 42 and is once again positioned to allow the surgeon to arm trocar 10, if so desired. If, after arming trocar 10, the surgeon determines that it is desirable to manually retract cutting tip 12 into cannula 14, the surgeon simply moves cannula 14 proximally with respect to cannula housing 18 and releases. Cannula 14 will then move distally under the bias of compression springs 68 rotating latch subassembly 147 counterclockwise. Latch finger 118 is thus moved out of engagement with shelf insert 102, allowing tension spring 28 to withdraw cutting tip 12 into cannula 14. The position of button 40 within slot 42 provides the surgeon with a visual indication of the position of cutting tip 12 relative to cannula 14. The audible click associated with the movement of latch 100 during the arming of trocar 10 also provides an aural signal to the surgeon. Many structures may be included toward the distal end of cannula 14 to facilitate the sensing of body wall counterforce to effectuate reciprocation of cannula 14, abutment surface 15 being but one example. Exemplary structures include radially spaced, outwardly directed protuberances, inflatable means of the type known in the art for fixedly positioning catheters and like devices, and flange means of varying geometries. Such structures may be fixedly secured to cannula 14 or repositionable along the longitudinal axis of cannula based on such factors as patient size and weight. While the above description contains many specific details, these details should not be construed as limitations on the scope of the invention, but merely as examples of preferred embodiments thereof. Those skilled in the art will envision many other possible variations that are within the scope and spirit of the invention as defined by the claims appended hereto.	A safety trocar is provided in which the cannula is reciprocally mounted to the cannula housing and reciprocates into the cannula housing when a proximally directed force is applied thereto. The piercing tip is maintained in the exposed position by a latching mechanism associated with the obturator shaft, and is automatically withdrawn into the cannula under the force of a spring when the proximal force is removed from the cannula, the cannula thus advancing distally and releasing the latching mechanism. Penetration force is maintained at a minimum, and safe and efficacious trocar entry is facilitated.	0
CONTRACTUAL ORIGIN OF THE INVENTION The United States Government has rights in this invention due to the Employer/Employee relationship of the inventor to the U.S. Department of Energy at the Pittsburgh Energy Research and Technology Center. BACKGROUND OF THE INVENTION This invention relates to a method for conditioning coal or other carbonaceous material prior to physical separation. In particular, the pretreatment involves the use of supercritical fluids in conditioning the carbonaceous material. Several factors limit the increased efficient utilization of coal. The gaseous release of the sulfur and nitrogen species in coal upon combustion has been and remains one of the most important limitations to increased utilization. Also the presence of high levels of mineral matter prohibit the use of coal, especially in markets traditionally dominated by petroleum products and natural gas. Commercial approaches to coal cleaning rely on differences in the physical properties of the coal and mineral matter to reject the undesirable portion of the coal. Many coals are known to be unresponsive to such techniques due to a variety of reasons, one of which is the incomplete segregation of mineral matter from the organic matrix of the coal. Chemical treatment of coal after physical beneficiation has been used in coal cleaning. Size reduction and classification in the physical process steps improve the activity of any chemical treatment that is later used. Recently, however, there have been suggestions to reverse this order of treatment to improve grindability, increase coal/ash fusion temperatures and preserve combustable volatiles. In one instance, a carbon dioxide and water mixture was used for the pretreatment of coal prior to its physical benefication. The coal was treated substantially below supercritical density and there was no significant extraction of soluble components into the carbon dioxide and water. It is known that certain gas phases maintained near to supercritical conditions are capable of taking up large amounts of solutes from liquid or solid materials. When conditions such as temperature or pressure are reduced to below critical, a substantial decrease in solubility results. Also increases, particularly in temperature, to well above critical likewise reduce solubility in the supercritical gas. For purposes of this application, the terms "supercritical solvent", "supercritical phase", or "supercritical fluid" refer to a gas or gas mixture, in some instances with solute, at or above critical temperature and critical pressure. There is increasing interest in the identification, development, and characterization of new coal derived fuels. Not only is there interest in beneficiating coal by the removal of ash and sulfur but also there is interest in beneficiating various char products from pyrolysis and gasification processes. Since a large portion of the calorific value of the coal ends up in the char, the benefication of this material can produce an important fuel. Removing the ash from char can produce serious difficulties in that char formation may fuse the organic and mineral matter and retard separation. Therefore, in view of the above, it is an object of the present invention to provide an improved method of beneficiating carbonaceous material. It is a further object to provide a method of reducing the ash content of a coal or char. It is a further object of the invention to provide a method of removing ash and sulfur from carbonaceous material without comminution to fine particles. It is also an object to provide a premium ash-free fraction in a process for the reduction of ash in a carbonaceous material. SUMMARY OF THE INVENTION In accordance with the present invention, a method of beneficiating carbonaceous material is provided. The method involves contacting the carbonaceous material with a supercritical fluid to extract a solute into supercritical phase leaving a solid residuum of the material. The solid residuum is subjected to a physical separation to provide a major fraction with reduced ash content and a minor portion of the residuum with high ash content. In other aspects of the invention, the solute is released from the supercritical phase to provide a premium fraction of reduced ash. This solute can be recovered by reducing the pressure of the supercritical fluid to below its critical pressure. The solute is at least one percent and advantageously is in the range of 1-15% by weight of the carbonaceous material. In more specific aspects, the supercritical fluid is an organic material having a critical temperature in the range of about 180° C. to 300° C. The fluid is selected from various materials capable of dissolving organic material from coal or coal char at a temperature near to but slightly above its critical temperature. By skillful selection of the supercritical fluid, sufficiently low process temperatures can be employed to avoid softening of the carbonaceous material. Advantageous selections of the supercritical fluid include cyclohexane and methanol. The use of methanol has been found to reduce sulfur content in the clean coal following physical processing. DETAILED DESCRIPTION OF THE DRAWINGS The present invention is illustrated in the accompanying drawings wherein; FIG. 1 is a schematic flow diagram illustrating a process for the benefication of carbonaceous material. FIG. 2 is a graph illustrating yield versus ash content in specific gravity, sink-float tests for raw coal and coal treated with various supercritical fluids. FIG. 3 is a graph of yield versus sulfur content in the specific gravity tests of FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The benefication process of the the present invention is decribed with reference to FIG. 1. Coal or other carbonaceous material 11 is contacted with a supercritical fluid 15 within vessel 13 and the products separated into a supercritical phase at 17 and residual solids at 19. Supercritical phase 17 includes a solute of soluble organic materials, up to about 15 weight percent of the carbonaceous material 11. The solute is released from supercritical phase such as by pressure reduction in vessel 21 from which a premium ash-free product 23 and a gas flow 25 are removed. As is well understood, the reduction of pressure below the critical pressure greatly reduces the solubility of many organic solutes in supercritical fluids. The resulting gas 25 is recompressed in recompression device 27 and cooled for recycle as supercritical fluid 15 into contact with the carbonaceous material 11. Ash-free product 23 can be recovered as a premium product 29 or combined at 31 with the clean carbonaceous material. Only a small portion of the carbonaceous material 11 is removed with the solute 17. The solute should be at least one percent and advantageously in the range of 1-15% by weight of the carbonaceous material. The greater portion of the material 11 is withdrawn from the supercritical treatment as solids 19 and is subjected to a physical separation process 33. Separation process 33 can be one of various physical separation methods based on specific gravity or froth flotation. In specific gravity separations, the ash and pyrite fractions settle in a liquid of selected specific gravity while a clean fraction 37 floats in the liquid for withdrawal. The separation based on specific gravity can be implemented by use of commercially available settling tanks or centrifugal equipment. Physical separation 33 also may be carried out as a froth flotation process. One particularly, advantageous process for separating pyrite from coal is described in U.S. Pat. No. 3,807,557 to Miller. This patent is incorporated by reference for this purpose. In this two-stage froth flotation process, coal is aerated to produce a froth product which is separated by conventional means such as froth scrapers or paddles. Coarse pyrite is removed as underflow. In the second stage of the process, the froth product from the first stage is subjected again to froth floatation using a coal floatation depressant and a pyrite floatation collector to remove a substantial portion of the remaining pyrite. The clean coal product is recovered with the underflow. Vessel 13 in which the supercritical treatment is performed can be any of the various types of gas-liquid-solid contacting devices. For instance, a column of liquid and solid through which a supercritical fluid is passed can be employed in a similar manner to that described in the assignee's copending patent application, Ser. No. 863,494, by Warzinski, entitled "Step-wise Supercritical Extraction of Carbonaceous Residua", filed 5/15/1986, Ser. No. 863,494. This application is incorporated by reference herein to describe means for contacting liquids and solids with supercritical fluids or solvents. Various organic solvents can be selected for use as a supercritical fluid in the present process. In order to enhance the solubility of the organic solute from the carbonaceous material into the supercritical solvent, the process is operated, above but near to, critical conditions. Advantageously, the process is operated at about 1.0 to 1.1 of the absolute critical temperature (Tc) and at about one to four times the absolute critical pressure (Pc). In these ranges solubility of the organic compounds of coal and char are greatly enhanced for extraction into the supercritical phase. It is of considerable importance that the supercritical fluid be selected to have critical temperatures within a range to permit solute dissolution without adversely affecting the subsequent ash separation. In general, critical temperatures of 180° C. to 300° C. (453-573 K) are contemplated for use. Temperatures much above this range can soften the coal or char causing it to flow around and more firmly entrap the ash and mineral matter into the matrix. Too low a critical and operating temperature will not permit the extraction of a premium ash-free product from the coal. The extraction of solute is of importance, not only to allow recovery of the premium product, but also to open the carbonaceous material matrix for subsequent separation of ash. Table 1 given below lists several solvents with their critical constants contemplated for the present process. TABLE 1______________________________________Critical ConstantsSolvent Tc °K. Pc Atm______________________________________2 Methylbutane 461 32.9N--Pentane 470 33.1Hexane 508 29.92 Methylpentane 498 29.95 Methylpentane 505 30.82,2-Dimethylbutane 489 30.72,3-Dimethylbutane 500 31Methanol 512 79.2Cyclohexane 553 40.1Benzene 562 49______________________________________ EXAMPLE 1 Illinois No. 6 coal is ground to pass about 1.5 millimeter screen apertures (14 mesh) and placed in a reaction vessel for contact with a flow of cyclohexane at a temperature of about 1.02 Tc and a pressure of about 2 Pc. The flow of cyclohexane is continued until about 10% by weight of the coal is extracted into supercritical phase. The solute is recovered as an ashfree, coal liquid by reducing the pressure to atmospheric, well below the critical pressure for cyclohexane. The residual solid coal is subjected to a specific gravity separation to recover the clean coal from the ash. EXAMPLE 2 The process of Example 1 is performed except that methanol, at 250° C. and at 325° C., is used as the supercritical solvent with other conditions substantially the same. EXAMPLE 3 As a comparision with the results obtained in the performance of the present invention, toluene having a critical temperature outside the preferred range, e.g. 320.4° C. is employed in a procedure similar to that of Example 1. The separation of ash in a specific gravity separation is clearly less effective than when cyclohexane or methanol are used as the critical solvent. Table 2 below gives the analyses of the untreated Illinois No. 6 coal used in the above Examples along with the various extracts obtained with the supercritical fluids. Extracts of about 9, 12, and 23% by weight were obtained for methanol, cyclohexane, and toluene respectively. TABLE 2______________________________________Analyses of Coals and Coal ExtractsCoalTreatment C H O N S ASH H/C --Mw______________________________________Illinois No. 6 62.92 4.68 12.40 0.86 4.80 14.34 0.886 --No TreatmentCyclohexane 83.45 6.75 6.51 1.01 2.30 0.12 0.964 460Toluene 82.65 6.21 7.91 1.05 2.35 0.05 0.895 579(Replicate) 82.08 6.23 7.97 1.19 2.64 0.02 0.904 531Methanol, 79.91 6.74 9.44 1.27 2.61 0.51 1.005 515250° C.Methanol, 81.13 6.91 8.55 1.14 2.20 0.15 1.015 434325° C.______________________________________ In order to determine the appropriate liquid specific gravity for use in the physical separations and to determine the effectiveness of the several supercritical solvents, a series of sink-float separations were conducted. Liquids of 1.25, 1.28, 1.30, 1.40, and 1.60 were used in these separation tests. For comparison the sink-float separations also were performed on raw coal. In each separation the yield, ash content and sulfur content of both the sink and float fractions were determined. The results of these tests are shown in FIGS. 2 and 3. In FIG. 2, the yield of clean coal that can be obtained at the various ash levels in specific gravity separations is shown. It is clearly seen that the treatment with supercritical toluene hinders the separation of ash by specific gravity methods while both cyclohexane and methanol provide improvement. FIG. 3 shows the yield of clean coal plotted against the total sulfur appearing in the coal. It is seen that treatment with supercritical methanol enhances the removal of sulfur in the performance of the present process. Treatment with supercritical cyclohexane or toluene result in a slight increase in sulfur content over that of coal without supercritical treatment. It is therefore seen that through use of the present invention, significant reduction in ash content can be obtained in a specific gravity-type separation following a supercritical extraction. Through selection of supercritical solvents of appropriate critical temperatures, the matrix of the coal or other carbonaceous material can be opened to facilitate ash separation in a specific gravity-type process. Although it has not been tried, it also is expected that such supercritical treatment will likewise enhance ash removal in froth flotation processes. These advantages can be obtained without resorting to ultrafine grinding and comminution of the carbonaceous material. In addition to the enhanced ash separation, the selection of methanol as the supercritical solvent provides some measure of sulfur removal with specific gravity-type separations. It is also seen that the present process provides a small fraction of substantially ash-free, premium coal product with reduced sulfur content. Although the present invention is described in terms of specific embodiments, it will be clear that various changes in the materials, processing conditions, and details of the invention can be made by one skilled in the art within the scope of the following claims.	A carbonaceous material such as coal is conditioned by contact with a supercritical fluid prior to physical beneficiation. The solid feed material is contacted with an organic supercritical fluid such as cyclohexane or methanol at temperatures slightly above the critical temperature and pressures of 1 to 4 times the critical pressure. A minor solute fraction is extracted into critical phase and separated from the solid residuum. The residuum is then processed by physical separation such as by froth flotation or specific gravity separation to recover a substantial fraction thereof with reduced ash content. The solute in supercritical phase can be released by pressure reduction and recombined with the low-ash, carbonaceous material.	8
DESCRIPTION OF THE INVENTION This invention relates to the field of mechanical arts. More specific ally, it relates to the field of tools used in the coal mining industry. Finally, this invention can best be described as a tool for removing and inserting the retaining clips that hold coal mining drill bits in the holders of rotating mining drums. A typical drill bit is a short lance-shaped piece of steel 16 cm long which fits into an irregular shaped metal holder. Several of such holders are welded to a rotating coal mining drum which moves the drill bits around in a circular motion against the surface of a coal seam to knock chunks of coal out of the seam during a mining operation. The drill bits are freely rotatable within the drill bit holders but prevented from coming out of the holders by omega-shaped metal retaining clips. When a bit finally becomes worn out from too much use and must be replaced. The retaining clip must be removed, the old bit discarded, a new bit put in the holder, and the retaining clip inserted onto the new drill bit. A problem occurs because the retaining clip is too strong to be removed with a person's fingers and it is not easy to reach inside the drill bit holder. So users generally try to pry off the retaining clip with a screw driver but this usually does not work very well and the screw driver usually has to be of just the right size to work. In the insertion of the retaining clip on a newly installed drill bit, the problem is even worse. It is extremely awkward to hold onto the retaining clip at just the right orientation inside the opening of the bit holder and to apply enough force to get the retaining clip to snap onto the drill bit. To do this people often try pliers, screw drivers, and hammers, but often get their finger nails chewed up in the process. Consequently, it is an object of the present invention to allow a user of the device to easily and conveniently remove a retaining clip from a drill bit. It is another object of the present invention to allow a retaining clip to be inserted onto a drill bit. The nature of the present invention is shown in the accompanying drawings. FIG. 1 shows a typical drill bit holder with a typical drill bit installed in the holder. FIG. 2 shows a standard drill bit retaining clip. FIG. 3 shows an exploded view of the five different parts which are assembled to make the present invention. FIG. 4 shows the assembled invention itself. Finally, FIG. 5 shows the present invention with the retaining clip held in it as it would be when the device is used to either remove or insert the retaining clip of a drill bit. Although all parts shown in these drawings are made of metal, they are depicted in the drawings as if they were transparent for the sake of clarity. More particularly, in FIG. 1 is shown a drill bit holder 1 which has an interior space 2 running through it. The drill bit holder has a cylindrical hole 3 also. The drill bit 4 sits in the hole 3 and protrudes all the way through the hole 3. On the portion of the drill bit which protrudes through the hole 3 there is an annular groove 5 in which groove is place a retaining clip to keep the drill bit 4 from coming out of the hole 3 during coal mining operations. In FIG. 2 is shown the retaining clip 6 which fits into the annular groove 5 of the drill bit 4 shown in the previous drawing. The retaining clip 6 is roughly shaped like the Greek letter omega but with the top part of the letter omega pulled up a bit. In FIG. 3 is shown an exploded view of the five different parts which are assembled to make the present invention, a device for removing and inserting the retaining clip from a drill bit. The first part of the device shown is a solid rectangular piston 7 which has a triangular prism shaped top 9 from which extends a cylindrical nib 10. The piston 7 also has a threaded screw hole 11 extending part way into it and the piston 7 also has a flat square surface 8. The present device possesses a hollow rectangular casing 12 with an upper lip 13 and a bottom lip 14. The hollow casing 12 also possesses an oblong hole 15. The present invention also has a cylindrical handle 16 with a screw threaded end 17. The device also has a spring 18. Finally, the invention also has a rectangular base plate 19. The way in which the parts of the invention are put together to form a functional device is shown in FIG. 4. The hollow rectangular casing 12 is welded to the rectangular base plate 19 where the bottom lip 14 of the casing meets the flat surface of the base plate 19 at one end of the base plate. The spring 18 is then dropped into the hollow casing 12 so that the bottom surface of the spring rests against the top surface of the base plate. Then the rectangular piston 7 is dropped into the hollow casing 12 so that the bottom surface 8 of the piston rests on the top surface of the spring 18. The cylindrical handle 16 is then attached to the piston 7 by screwing the threaded end 17 of the handle through the oblong hole 15 into the threaded hole 11 of the piston 17. The assembled device then looks as it is shown in the drawing, ready for use. In FIG. 5 is shown the device as it is used to remove or insert a retaining clip. The nib 10 of the piston 7 has been placed on the inside of the top portion of the omega-shaped retaining clip 6, while the user has squeezed the handle 16 toward the base plate 19, thus securing the outer edges of the retaining clip 6 against the upper end 13 of the casing 12. With the retaining clip 6 secured to the device in this position as shown in FIG. 5, the retaining clip can be easily removed from or inserted onto the annular groove of a drill bit. When the user relaxes his grip from squeezing the handle 16 toward the base plate 19, the spring 18 then pushes the piston 7 upward in the casing 12 so that the nib 10 does not press the edges of the retaining clip 6 against the upper edge 13 of the casing 12 so that the grip of the device on the retaining clip is released. Typical dimensions involved in the best mode practice of this invention are as follows (referring to FIGS. 1-5): A standard drill bit 4 has a length of 16.0 cm. The hole 3 in the drill bit holder 1 through which the drill bit fits has a diameter of 3.0 cm. The retaining clip 6 is made from a steel strip with a cross section of 0.4 cm by 0.2 cm bent roughly in the shape of the Greek letter omega. On the device itself, the base plate 19 is 12.5 cm long, 2.5 cm wide, and 0.3 cm thick. The casing 12, which is welded to the base plate, is 7.5 cm long, measures 1.5 cm on each side and is made of metal which is 0.1 cm thick. The spring 18 is made of coiled steel with a 0.1 cm cross section diameter. The outer diameter of the coil itself is 1.2 cm. The rectangular piston 7 has a total length of 6.3 cm from nib 10 to the bottom surface 8. The piston 7 measures 1.3 cm on each side. The threaded screw hole 11 has a diameter of 0.9 cm. The cylindrical nib 10 is 0.5 cm long and possesses a diameter of 0.5 cm. The handle 16 is 13.0 cm long and has a diameter of 0.9 cm. The oblong hole 15 in the casing 12 through which the handle 16 fits has a length of 2.2 cm and a width of 1.0 cm. All parts of this invention are preferably made out of steel. It should also be apparent that the above dimensions are given by way of the best mode example contemplated by the inventor and that the said dimensions may be varied without departing from the scope of this invention as claimed by the Inventor.	A device for removing and inserting drill bit retaining clips. The device having a casing rigidly connected to a base plate, the casing containing a piston, one end of the piston contacting a spring against the base plate, the other end of the piston having a nib, the piston also includes a handle, wherein the piston may be pressed toward the base plate allowing the nip to grip a retaining clip against the casing, so that the retaining clip can be removed or inserted while being held.	4
CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims priority on Canadian Patent Application No. 2,438,096, filed on Aug. 22, 2003, by the present applicant. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to the field of disc filters used in the pulp and paper industry for processing paper machine white water. [0004] 2. Background Art [0005] A disc filter machine used in the pulp and paper industry is comprised of a hollow central rotating shaft with approximately twenty radially symmetrical sectors connected thereon, and a vat enclosing the sectors and extending along the length of the shaft. The central rotating shaft comprises axial filtrate channels and is connected to a filtrate valve. The filtrate, which is drained via the sectors into the corresponding filtrate channels of the shaft, is vacuumed therein by way of barometric legs. [0006] The sectors are accessible from a platform through hood doors of the disc filter machine. A sector can be described as a plane figure bounded by two radial edges and an outer arcuate edge therebetween. The radial edges converge to form a neck on the sector. Furthermore, the sector is defined by an arrangement of flow paths for directing filtrate which terminate at an exit opening at the neck of the sector and are connected to corresponding channel openings on the central rotating shaft. The neck of the sector is joined to an arcuate base plate which acts as a means of attachment for the sector onto the shaft. The curvature of the arcuate base plate is identical to the curvature of the shaft, thus enabling the base plate to be superimposed thereon. Further, the arcuate base plate of the sector is bolted onto the shaft at two opposing locations. [0007] The working principle of the disc filter consists of the sectors rotating by way of the hollow central shaft, thus dipping into a slurry or white water bath in the vat. The slurry or white water consists of a mixture of water, fibre particles and other impurities. As the sectors rotate out of the slurry bath, a fibre residue starts to form under gravity as the sectors are dewatered. The filtrate is drained via the sectors to the corresponding filtrate channels in the central shaft and is directed to a drainage opening where it is removed. Thus, in order to seal the passageway of the filtrate from the sector to the shaft, a gasket is required therebetween. [0008] The conventional gaskets presently utilized are manually glued onto the arcuate base plate at the end of the neck portion of the sectors to act as a sealing means for the channel connection between the shaft and the sector. In order to replace a used gasket, the sector must be manually unbolted from a distance by way of a pneumatic fastening device. Then, the gasket must be forcibly removed with scraping tools, and finally the concave contact surface of the sector must be thoroughly cleaned to ensure that no fibre particles from the slurry bath or the filtrate remain thereon. The washing is essential because the glue must be applied to a very clean surface in order for it to stick well. Once the glue has been applied and the conventional gasket has been stuck onto the cleaned surface, a curing period is required for the adhesive. During the time the sector is detached, the disc filter machine is not in operation. Thus, the production of quality filtrate from white water only commences when the sector is reattached. In the event that a number of gaskets need to be manually replaced by a single worker, the production downtime is considerable. Furthermore, the additional labour will be expensive. [0009] Consequently, it is desirable to simplify the method in order to maximize productivity of the disc filter. machine. What is needed is a flexible gasket, propitiously suited for sectors, that is easily applied, easily removed and easily reapplied with the stability required to make an efficient gasket seal. SUMMARY OF INVENTION [0010] It is therefore an aim of the present invention to provide a method of replacing a gasket on a sector of a disc, filter which substantially overcomes the disadvantages of the prior art. [0011] It is another aim of the present invention to provide a gasket adapted to be easily installed on an arcuate base plate of a sector. [0012] It is yet another aim of the present invention to provide a sealing gasket device substantially retaining its structural integrity to remain properly oriented on an arcuate base plate surface between a sector and a corresponding shaft, thus optimising the seal and minimizing deformation and improper orientation of the gasket during installation. [0013] Therefore, in accordance with the present invention, there is provided an adhesive-free gasket for use on a sector of a disc filter wherein the sector includes a base plate having an opening, the gasket comprising a first surface and a second surface, an inner edge on the first surface and the second surface defining at least one aperture therethrough, at least a first mechanical attachment on a periphery of the gasket, the first mechanical attachment being adapted to engage an edge of the base plate, and at least a second mechanical attachment on the periphery of the gasket, the second mechanical attachment adapted to engage an opposite edge of the base plate, wherein the first and second mechanical attachments are suitable to engage the gasket onto the base plate of the sector without adhesive, and whereby the aperture in the gasket will coincide with the opening in the base plate. [0014] Further in accordance with the present invention, there is provided a method for replacing a gasket on a sector of a disk filter wherein the sector includes an arcuate base plate having an opening, the method comprising the steps of providing an adhesive-free gasket having a first surface, a second surface, a first mechanical attachment and at least a second mechanical attachment on a periphery of the gasket, the first and second attachments being adapted to engage edges of the arcuate base plate of the sector, and an inner edge on the first surface and the second surface defining at least one aperture therethrough, removing a used gasket from the arcuate base plate of the sector, aligning the inner edge of the gasket with edges of the opening in the arcuate base plate of the sector by superimposing the first surface of the gasket thereon, and engaging the first mechanical attachment onto one of the edges of the arcuate base plate of the sector and engaging the second mechanical attachment onto another one of the edges of the base plate of the sector, wherein the gasket is adapted to be engaged onto the arcuate base plate without adhesive. [0015] These and other objects and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0016] Having thus generally described the nature of the invention, reference will now be made to the accompanying drawings, showing by way of illustration a preferred embodiment thereof and in which: [0017] FIG. 1 is a perspective view of a gasket in accordance with a preferred embodiment of the present invention; [0018] FIG. 2 is a top plan view of the gasket according to the present invention; [0019] FIG. 3 is a perspective view of a sector according to the prior art; [0020] FIG. 4 is a perspective view of an arcuate base plate of a sector with a conventional gasket glued thereon, according to the prior art; and [0021] FIG. 5 is a perspective view of a gasket in accordance with an alternative embodiment of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS [0022] Referring now to FIG. 4 of the drawings, a sector used on a disc filter machine commonly employed today is illustrated. The sector 10 is defined by two radial edges 12 and an outer arcuate edge 14 . The radial edges 12 converge to form a neck 16 on the sector 10 whereupon an arcuate base plate 18 is joined. In FIG. 3 , the arcuate base plate 18 of the sector 10 , which acts as a means of attachment for the sector 10 onto the central shaft, is shown with the conventional gasket presently utilized glued onto the contact surface 19 thereof. Further an exit channel aperture 20 of the sector 10 wherethrough filtrate passes is centrally located in the arcuate base plate 18 . [0023] With concurrent reference to FIGS. 1, 2 and 3 , a gasket in accordance with the present invention is shown at 22 . The gasket 22 is generally defined by a flexible portion 24 , which is preferably resilient. Referring concurrently to FIGS. 1, 2 and 4 , the flexible portion 24 comprises inner edges 25 , 26 , 27 , and 28 defining a central aperture 29 preferably of similar shape and size as the exit channel aperture 20 of a sector 10 . A raised sealing portion 30 with semi-circular cross-section located on the flexible portion 24 of the gasket 22 , contours the central aperture 29 . The gasket 22 also comprises protruding tabs 32 and hooks 34 on its periphery adapted to be used on the edges of an arcuate base plate 36 of a sector 10 . Furthermore, bands 38 are positioned parallel and adjacent to longitudinal inner edges 27 and 28 of the central aperture 29 , and are provided for maintaining the structural integrity of the gasket 22 . [0024] Referring more particularly to FIG. 1 , the flexible portion 24 defines a front surface 40 and a rear surface 42 , both sharing exterior edges 44 , 45 , 46 , and 57 . The edges 46 and 47 comprise U-shaped edges 48 , as a preferred embodiment of this invention, positioned at the half way mark. The U-shaped edges 48 ensure proper alignment of the gasket 22 on the connecting arcuate base plate 18 ( FIG. 4 ) of the sector 10 with respect to the attachment bolts, as will be described hereinafter. [0025] The inner edges 25 , 26 , 27 , and 28 defining the central aperture 29 of the flexible portion 24 are parallel to the related exterior edges 44 , 45 , 46 , and 47 of the gasket 22 . The central aperture 29 acts as a trough for filtrate passing from the sector 10 ( FIG. 3 ) to the central rotating disc shaft by way of corresponding filtrate channels. [0026] Referring concurrently to FIGS. 1, 2 and 4 , both the flexible portion 24 and the central aperture 29 may vary in size depending on the size of the arcuate base plate 18 of the sector 10 and on the size of the exit channel aperture 20 therein. Preferably, flexible portion 24 is designed to cover the entire arcuate base plate 18 surface area of the sector 10 , thus ensuring the most effective seal by reducing the risk of fibre build-up which tends to form along the exterior edges of conventional sealing gaskets. This fibre build-up could develop between the contact surface 19 of the sector 10 and that of the shaft. Advantageously, the present invention is characterized by matching the surface area of the flexible portion 24 with that of the arcuate base plate 18 , consequently reducing the possibility of fibre deposition therebetween. [0027] Particularly, the flexible portion 24 is preferably made of rubber, or rubber-like material resistant to oil and fluid, such as pellethane 2363-80A. The aforementioned material will compress slightly under pressure, but offers sufficient firmness so as to become firmly seated and form a tight seal between the arcuate base plate 18 and the shaft. [0028] Furthermore, in a preferred embodiment of the present invention, the gasket 22 comprises protruding tabs 32 as a means of attaching the gasket 22 to the arcuate base plate 18 of the sector 10 , as shown concurrently in FIGS. 1, 2 and 4 . Due to the fact that the thickness of the arcuate base plate 18 may vary with respect to the type of sector utilized, it is preferable that the tabs 32 be pliable and also variable in length in order to adapt to the thickness of the arcuate base plate 18 . Ideally, the tabs 32 are made of a malleable metallic element such as aluminum, stainless steel or the like. [0029] In another embodiment of the present invention best illustrated in FIG. 1 , bands 38 extend parallel to the exterior edges 46 and 47 of the flexible portion 24 of the gasket 22 , and perpendicularly intersect and surpass the opposing exterior edges 44 and 45 to yield the aforementioned protruding tabs 32 . In this embodiment, the bands 38 are integrally joined to the tabs 32 and are also integrally moulded into the flexible portion 24 along a flat plane between the front surface 40 and the rear surface 42 . The bands 38 are preferably made of a malleable metallic element. Further, the bands 38 are adjacent to inner edges 27 and 28 defining the central aperture 29 , extending on both sides thereof to maintain the structural integrity of the gasket 22 . It should be noted that although the bands 38 and the tabs 32 are described as integrally joined and metallic, other alternatives can also readily be used. [0030] Referring concurrently to FIGS. 1, 2 and 4 , when the reinforced sealing gasket 22 is positioned on the arcuate base plate 18 of the sector 10 around the exit channel aperture 20 therein, and attached by way of the tabs 32 onto the edges of the arcuate base plate 36 , the bands 38 can be shaped into the curvature of the arcuate base plate 18 to ensure a proper seal. The bands 38 optimize the seal by having the gasket 22 pressed up against the arcuate base plate 18 before the sector 10 is reinstalled onto the cylindrical shaft. Considering that the worker installing the sector 10 on the central rotating disc shaft is positioned away from the arcuate base plate 18 , the bands 38 ensure that the gasket 22 stays in position on the arcuate base plate 18 . Moreover, the risk of an obstruction or any fibres getting between the arcuate base plate 18 and the gasket 22 is reduced. In addition, gasket displacement is avoided during sector reattachment because the bands 38 register the gasket 22 into place at the onset of the installation procedure. The bands 38 act as reinforcing members, minimizing deformation due to friction and compressive forces as well. Thus, the bands 38 help optimize the seal, ensuring that the gasket 22 is fully effective for sealing the sector 10 onto the shaft. [0031] Moreover, as best seen in FIG. 2 , the central aperture 29 is outlined by the raised sealing portion 30 with semi-circular cross-section located on the front surface 40 of the flexible portion 24 , whose purpose is to optimize the seal between the sector 10 and the shaft. The raised sealing portion 30 is preferably resilient and accordingly shaped to surround the central aperture 29 as well as the adjacent bands 38 . In FIGS. 1 and 2 , the raised sealing portion 30 is illustrated in a rectangular formation with rounded corners. The raised sealing portion 30 is an elastomeric liner seal, which when compressed against the arcuate base plate 18 of the sector 10 acts as an added barrier reducing leakage between the arcuate base plate 18 and the gasket 22 . [0032] In addition, referring concurrently to FIGS. 1, 2 and 4 , the gasket 22 encompasses pairs of hooks 34 protruding from the exterior edges 46 and 47 of the flexible portion 24 , preferably in juxtaposition with the U-shaped edges 48 thereon. The hooks 34 , symmetrically located on opposing sides of the U-shaped edges 48 , are means of attachment and alignment for the gasket 22 onto the arcuate base plate 18 of the sector 10 . The hooks 34 oppose the tabs 32 on the flexible portion 24 , but essentially have the same function which consists of attaching the gasket 22 to the arcuate base plate 18 of the sector 10 . Advantageously, the hooks 34 ensure that the U-shaped edges 48 are properly aligned with, and centered on the bolt holes 50 ( FIG. 4 ) on the arcuate base plate 18 . [0033] In another embodiment of the present invention, the gasket 22 is provided with crenellated portions 52 which are best illustrated in FIG. 1 . More distinctively, the whole crenellated portion 52 can be described as having two merlons 54 and one crenel 56 , and is shown as integrally moulded within the flexible portion 24 and integrally connected to the aforementioned hooks 34 . [0034] It is pointed out that an alternative configuration can also be effectively employed whereby the crenellated portions 52 are integrally connected to the aforesaid bands 38 and hooks 34 . As shown in FIG. 5 , the integrally moulded piece 58 is a combination of the crenellated portions 52 connected to the hooks 34 and to the bands 38 which are integrally joined to the tabs 32 . Preferably, the crenellated portions 52 are at right angles with the bands 38 . [0035] Referring concurrently to FIGS. 1, 2 , 4 and 5 , it is preferred that the crenellated portions 52 are in juxtaposition with the U-shaped edges 48 because the crenellated portions 52 act as spacers between the arcuate base plate 18 and the cylindrical shaft. Thus, they protect against over compression of the flexible portion 24 , particularly at the area surrounding the U-shaped edges 48 , whereupon the exerted bolt force is strongest. Due to the fact that the sector 10 is manually reattached from a distance by way of a pneumatic fastening device, it is difficult for a worker to determine the magnitude of the torque applied onto the gasket 22 through the bolts inserted therein. It is important that the compressive force applied to the gasket 22 be of comparable magnitude on both sides to ensure a proper seal. Thus, without the spacers and in the event that one side of the flexible portion 24 is over compressed once the first of two bolts is inserted, the gasket 22 will have a tendency not to adhere as well to the arcuate base plate 18 on the opposing side whereat the bolt has not yet been installed. As a result, this occurrence creates a problem with the seal when the remaining bolt is put into place. This is largely due to the unequal distribution of compressive forces on the bolted sides of the gasket 22 . [0036] Advantageously, the crenellated portions 52 of the present invention, which are preferably made out of a metallic element, act to oppose the applied bolt force. Hence, a worker can more accurately determine the magnitude of torque needed when using a pneumatic fastening device to render an even distribution of pressure on the gasket 22 . [0037] Due to the abovementioned embodiments described hereof, the effectiveness of the seal between the arcuate base plate 18 and the cylindrical shaft is thereby optimized. The tabs 32 and hooks 34 are means of attachment and alignment of the gasket 22 onto the arcuate base plate 18 . The bands 38 maintain the structural integrity of the gasket 22 , while the raised sealing portion 30 ensures the integrity of the seal. Finally, the crenellated portions 52 in juxtaposition with the U-shaped edges 48 ensure that the compressive force on both sides of the gasket 22 be of comparable magnitude. [0038] With concurrent reference to FIGS. 1, 2 and 4 , the gasket 22 depicted above will now be incorporated into the method proposed in an embodiment of the present invention. With the foregoing arrangement, the gasket 22 is manually attached to the relatively clean arcuate base plate 18 of the sector 10 by way of the following methodical steps. In carrying out this method, the gasket 22 is hooked onto the peripheral edges of the arcuate base plate 36 by way of the hooks 34 , while ensuring that the U-shaped edges 48 are aligned with, and centered around the bolt holes 50 on the arcuate base plate 18 . Thus, the proper positioning of the gasket 22 thereby registers the inner edges 25 - 28 of the flexible portion 24 defining the central aperture 29 with the perimeter of the exit channel aperture 20 of the arcuate base plate 18 . [0039] Next, the tabs 32 are folded over the opposing exterior edges 44 and 45 to secure and stabilize the gasket 22 into place. Due to the fact that the arcuate base plate 18 is a concave surface, the bands 38 need to be manually form fitted by simply applying pressure so that the gasket 22 takes the shape of the surface. Once the gasket 22 is fixed onto the sector 10 , the latter is reattached to the rotating cylindrical shaft and bolted thereon. The bolts further pin down the gasket 22 , keeping it tightly pressed between the respective surfaces. [0040] The foregoing description of the preferred embodiments is considered as illustrative only of the principles of the invention. Further, changes and variations which are obvious to those skilled in the art are also included in the scope of this invention because it is not desired to limit the invention to the exact construction and method shown and described.	An adhesive-free gasket for use on a sector of a disc filter. The gasket comprising a first surface and a second surface. An inner edge on the first and second surface defining at least one aperture therethrough. Two tabs on the periphery of the gasket are suitable to engage an edge of the base plate of the sector without adhesive, whereby the aperture in the gasket will coincide with the opening in the base plate.	3
This is a continuation of application Ser. No. 125,534, filed 11/25/87. BACKGROUND OF THE INVENTION The present invention relates to an improved endoscope construction and more particularly to an endoscope construction including means for controlling the flexure of an endoscope tube especially the rigidity and curvature of the endoscope tube. The use of an endoscope for diagnostic investigation or other medical intrusion of various body cavities has become an important procedure for physicians. Endoscope devices are known under various medical instrument names; including, flexible cystoscope, flexible neproscope, flexible gastroscope, flexible bronchoscope, flexible choledochoscope, sigmoidoscope, arthroscope, laparoscope and flexible utererscope. Most of the identified endoscopes have a flexible probe or tube which is designed to pass into a curved body passage. The tube typically incorporates a diagnostic or surgical instrument for observation or operation within the body through the tube from outside the body. In recent years many patents have issued for various types of endoscopes. These patents disclose, for example, use of optical lens or, in recent years, fiber optics to provide for visual diagnosis. Boebel in U.S. Pat. No. 4,503,843 is typical and discloses a device which utilizes a telescope. Seike in U.S. Pat. No. 4,607,619 discloses an endoscope device utilizing a fiber optic or light guide technique. More recently, Arakawa in U.S. Pat. No. 4,651,202 discloses a video endoscope system wherein the diagnostic information is transmitted from the distal end of an endoscope tube via fiber optic fibers to a proximal end where it is transmitted to a cathode ray tube or television. Endoscopes are also used for performing surgical procedures. A series of patents teach this use of an endoscope including the following: ______________________________________U.S. Pat. No. Inventor Title Issue Date______________________________________4,137,920 Bonnet Endoscopes 2/6/794,607,620 Storz Medical Gripping 8/26/86 Instrument4,625,713 Hiraoka Instrument Incorporated 12/2/86 in a Resectoscope4,641,634 Storz One-Hand Hysteroscope 2/10/874,653,476 Bonnet Instrument Insert for a 3/31/87 Uretero-Renoscope______________________________________ There are additional patents relating to the construction and use of the endoscope instruments including the following: ______________________________________U.S. Pat. No. Inventor Title Issue Date______________________________________4,569,333 Bel, et al Optical Instrument 2/11/86 Including a Focusing Eyepiece and an Endoscope4,576,435 Nishioka Endoscope Including a 3/18/86 Reflector Related by an Inequality for Uniform 3/18/86 Light Distribution4,587,972 Morantte, Device for Diagnostic 5/13/867 Jr. and Therapeutic Intravascular Intervention4,633,855 Baba Endoscope Apparatus 1/6/87______________________________________ Generally it is desirable that the endoscope have a flexible tube in order to permit the instrument to follow the circuitous canals and paths defined by body cavities and canals. Many of the prior art references listed above disclose flexible endoscopes. However, there has remained a need to provide an improved mechanism for controlling the flexure of an endoscope tube in order to more efficiently guide the endoscope through a body cavity. As part of flexure control, there has developed a need to accurately and precisely control the stiffness or rigidity of an endoscope tube. Control of rigidity of the tube is especially critical to facilitate insertion of the tube into a curved body tube or cavity. If the tube is too rigid, insertion may damage the body. If it is too flexible, the tube cannot be properly inserted into the body. As a further part of flexure control, precise control of curvature of the endoscope is desired. These considerations inspired the development of the present invention. SUMMARY OF THE INVENTION In a principal aspect, the present invention comprises an improved flexible endoscope of the type which includes a hollow, elongate, flexible tube having a distal end which is inserted into a body cavity and a proximal end which is utilized as a viewing or control end. A sensor system typically extends through the flexible tube from the distal end to the proximal end. The sensor system is capable of transmitting diagnostic information from the distal end to a sensor or observation system at the proximal end. The invention relates particularly to the means for controlling the flexure (i.e. rigidity and curvature) of the tube. The means for controlling flexure comprises at least one hollow, longitudinal, flexible and optionally expandible conduit incorporated within the endoscope tube and extending longitudinally through the tube. The conduit is preferably positioned radially with respect to the center line axis of a segment of the flexible tube. In a preferred embodiment, there are a plurality of such conduits. Pressure means is also provided to pressurize the conduits and thereby control the rigidity of the associated tube segment. Pressure means also is effective to elastically expand one or more of the conduits longitudinally and sequentially in order to vary the curvature of the tube. Thus, it is an object of the invention to provide an improved flexible endoscope construction. Yet a further object of the invention is to provide a flexible endoscope construction which is comprised of a tube having a series of flexible segments, each segment being independently controllable to vary the rigidity and curvature. A further object of the invention is to provide an endoscope which is flexible and wherein the flexure is controllable by means of fluid pressurizable and elastically expandible conduits parallel to the longitudinal axis of the endoscope and spaced from the centerline axis thereof. Yet a further object of the present invention is to provide a construction for controlling the rigidity or curvature of segments of an endoscope which system may be incorporated in or with instruments and sensors associated with prior art endoscopes. Yet a further object of the present invention is to provide a mechanism for controlling the rigidity or curvature of an endoscope which is economical and which is not overly cumbersome or burdensome and therefore may be incorporated efficiently with or as part of existing endoscopes. A further object of the invention is to provide a construction for independently controlling the rigidity and curvature of at least a segment of a flexible endoscope tube. Another object of the invention is to provide a construction for controlling the rigidity or curvature or both of a series of segments forming at least part of a flexible endoscope tube. These and other objects, advantages and features of the invention will be set forth in the detailed description which follows. BRIEF DESCRIPTION OF THE DRAWING In the detailed description which follows, reference will be made to the drawing comprised of the following figures: FIG. 1 is a perspective view of the flexible tube portion of the endoscope of the present invention including the distal end and an intermediate section; FIG. 2 is a perspective view similar to FIG. 1 wherein the endoscope has been made rigid and curved by operation of the control mechanism for the endoscope; FIG. 3 is an enlarged cut-away perspective view of the distal end and flexible end segment of the endoscope shown in FIG. 1; FIG. 4 is a cross sectional view of the flexible end segment of the endoscope shown in FIG. 3 taken along the line 4--4; FIG. 5 is a cross sectional view along the longitudinal axis of the endoscope shown in FIG. 2 taken along the line 5--5. FIG. 6 is a perspective view of a control mechanism for the endoscope of the invention; FIG. 7 is a schematic, cross sectional view of a check valve associated with the control mechanism; FIG. 8 is a cross sectional schematic view of the control mechanism of FIG. 6; and FIG. 9 is yet another cross sectional view of the control mechanism of FIG. 6 similar to FIG. 8. DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates, in a perspective view, a flexible tube 10 near the distal end 12 of an endoscope device incorporating the invention. The tube 10 may be curved in a desired direction or made rigid when appropriate. The construction thus permits adjustment of rigidity as well as curvature. That is, if the tube is too flexible, then it cannot be easily guided into a body cavity. If it is too stiff, then it cannot comfortably be directed through curved body cavities or canals. Thus, the present invention seeks to provide an endoscope tube wherein the stiffness of the tube is adjustable, and the curvature is also adjustable in order to most efficiently guide the tube through curved cavities or canals. In the drawings, therefore, the flexible tube 10 of the endoscope is depicted. The instrument or proximal end of the endoscope is not depicted but may be of any construction known to those of ordinary skill in the art depending upon the particular medical or diagnostic instrument involved. Typically, the endoscope tube 10 has a hollow elongate passage 22 including, for example, a fiber optic member which extends the length of the tube 10 to provide not only a light source path but also a transmission lens. The fiber optic element thus connects with appropriate instruments at the proximal end of the instrument, as shown in the prior art references previously identified, for the purpose of permitting a visual diagnosis. In some instances, medical instruments are inserted into the passage 22 of tube 10 to provide for the taking of a biopsy, for example, or for other surgical or diagnostic purposes. The tube 10 is preferably elastic. The flexible tube 10 is comprised of a series of connected segments 14. Each segment 14 has approximately the same dimensions in length and diameter and constitutes a continuous portion of the tube 10, although the dimensions of each segment 14 need not be identical. Each segment 14 is independently controlled insofar as stiffness and curvature by separate control means in the manner to be described below. FIG. 2 illustrates a benefit that results from having each of the segments 14 independently controlled to provide, for example, a controlled amount of stiffness as well as curvature. Thus, the ultimate end segment 14A may be curved upwardly. The next adjacent segment 14B may be rigid and straight, and the next segment 14C may be curved downwardly. Referring to FIG. 3 and subsequent figures, the construction and operation of the individual segments 14 is described by reference to the end segment 14A near the distal end 12 of the endoscope. Segment 14A has a centerline axis 16. A plurality of four specially constructed conduits 18, 19, 20 and 21 extend parallel to the longitudinal axis 16 within segment 14A. Each conduit 18, 19, 20, 21 is positioned at an equal radial distance from the axis 16 and is equally spaced on a cylindrical locus from one of the other conduits 18, 19, 20, 21. The interior part of the segment 14A is, in the preferred embodiment, hollow defining the hollow tubular passage 22 for receipt of an instrument or a fiber optic package as previously described. The instrument package or fiber optic package or the like, which is retained within the passage 22, is plastic, i.e. it assumes the curvature of segment 14A. Each of the conduits 18, 19, 20 and 21 has a similar construction. That is, each conduit 18, 19, 20, 21 is generally tubular and is comprised of an elastic material having an accordion configuration or cross section, as depicted in FIG. 5, when the segment 14 is in a relaxed condition. That is, the cross sectional configuration of the conduit 21 is such that folds 23, defining the conduit 21, are not extended or elongated when the conduit 21 is not elastically stressed or is relaxed. Further, each of the conduits 18, 19, 20 and 21 is closed or sealed at its distal end, e.g. end 19B. The opposite end, e.g. end 19C, is connected to a pressure source, for example, a gas or liquid pressure source. Admission of pressurized gas to a first pressure level within the conduits 18, 19, 20 and 21 will tend to cause the conduits 18, 19, 20, 21 to become rigid. This, in turn, will make the segment 14A rigid inasmuch as it is reinforced by the four parallel, inflated conduits 18, 19, 20, 21. In order to make the segment 14A rigid. the pressure in each of the conduits 18, 19, 20 and 21 should be maintained equal. Further, in such instance the pressure in each of the conduits 18, 19, 20, 21 should preferably be at a level which will not cause the conduits 18, 19, 20, 21 to expand in the direction of the longitudinal axis 16. In order to effect curvature of the segment 14A, differential pressures are provided to the conduits 18, 19, 20 and 21. For example, referring to FIG. 5, pressure in the conduit 19 is increased and pressure in the conduit 21 is maintained at an ambient pressure or decreased relative that in conduit 19 in order to cause curvature of the segment 14A. Thus, the conduit 19 is pressurized a sufficient amount to cause the conduit 19 to, in essence, elastically elongate or extend axially. Simultaneously the pressure in the conduit 21 may be maintained at an ambient level. Alternatively, a vacuum or a partial vacuum may be provided within the conduit 21. This will cause the segment 14A, which receives the conduit 21, to assume an arcuate or curved shape as depicted. Curvature of segment 14A results since the conduit 19 becomes elongated and the conduit 21 remains the same length or foreshortens. To insure such curvature, the opposite ends of each conduit 18, 19, 20, 21 are preferably fixed to the segment 14A whereas the portion of the conduits 18-21 intermediate the ends is not fixed to the segment 14A, but rather rides in a passage in segment 14A. For example, conduit 19 is fixed to segment 14A at conduit ends 19B and 19C. Intermediate the ends 19B and 19C, the conduit 19 is slidable in a passage in segment 14A. The conduit 19, when initially inflated will thus become rigid and maintain a length equal to the original spacing of ends 19A and 19B. As the pressure in conduit 19 increases beyond a threshold elastic pressure limit, the conduit 19 elongates thereby elongating one side of the segment 14A. Segment 14A is thus somewhat elastic so as to respond to the elongation resulting when the conduit 19 is inflated and elongated. Curvature in any direction can be effected by increasing the pressure in the manner described in any one or two of the four conduits, 18, 19, 20 or 21. By providing variable increased pressure to combinations of adjacent conduits, it is possible to effect highly controlled curvature of the segment 14A. Note that each of the conduits 18, 19, 20 and 21 is elastic. Thus, when pressure that causes elastic elongation of a conduit 18-21 is removed from the conduit 18, 19, 20 or 21, the conduit 18, 19, 20 or 21 will resume its original shape. The segment 14A thus, being slightly elastic, responds to the pressure pattern imparted by the elastic conduits 18, 19, 20 and 21. In practice, four conduits 18, 19, 20, 21 provide sufficient means for control of curvature of each segment 14. However, additional conduits may be provided in a radially spaced pattern about the centerline axis 16 in order to further enhance the control of the endoscope segment 14. Further, in practice each endoscope segment 14 includes its own separate set of conduits which are elastic and expandible in the manner described. In this manner each segment 14 of the endoscope is separately controllable in terms of rigidity as well as curvature. FIGS. 6, 7, 8 and 9 illustrate a type of pressure control device which may be used to control pressure in conduits 18-21 and thus the rigidity and curvature of the segment 14. As shown in FIGS. 6 and 7, the conduits 18, 19, 20 and 21 connect to a control box 28 having a control lever 30 pivotally mounted on a bearing 32 in a seat 34 in a throughbore in a plate 33 within the housing 28. Plate 33 separates the housing 28 into a high pressure chamber 62 and a low pressure chamber 64. Suitable, variable pressure sources 61, 63 are attached to chambers 62, 64, respectively. The lever 30 includes a rigid, hollow cylindrical rod 36 which supports a valve actuator 38. The end of the rod 36 is connected with the bearing 32. In this manner the rod 36 is pivotal so as to permit the actuator 38 to engage either valve 40 or 42, for example, associated with conduits 18 and 20, respectively. The valves 40 and 42 are spring biased by associated springs 44 and 46 to the closed position until one of them is actuated by the actuator 38 due to pivoting of the rod 36. When in the closed position, valves 40, 42 are positioned to vent associated conduits 18, 20 to atmosphere via vent passages 41, 43. The hollow rod 36 includes a telescopically received, flexible rod 48 supporting a second actuator 50. The rod 48 may be telescopically extended to the position shown in FIG. 9 by means of a lever 52 which can be positioned in a lower notch 53 rather than an upper notch 55 defined in hollow rod 36. Thus, the actuator 50 may be positioned for simultaneous engagement or disengagement with valves 54 and 56 which are normally closed due to actuation of associated springs 58 and 60. The valves 54 and 56 are associated respectively with the conduits 18A and 20A in FIG. 6. Conduits 18A, 20A are vented to atmosphere via vents 55, 57 when valves 54, 56 are closed. The operation of the controls will be described with respect to the conduits 18 and 20. To control rigidity only, pressure from chamber 64 is provided via all conduits 18A, 20A (also 19A, 21A) simultaneously. Thus, the lever 52 is in the position illustrated in FIG. 9 in a lower notch 53 rather than an upper notch 55 of rod 36. The actuator 50 thus will simultaneously engage the ball valves 54, 56 thereby providing low pressure through conduits 18A, 20A through check valves 70 to the conduits 18, 20. When controlling rigidity in this manner, the lever 30 is maintained in a neutral or center rest position. To control curvature, the control lever 30 may be actuated by movement in any direction to thereby effect high pressure flow to any of the conduits 18, 19, 20 or 21. Thus, in order to effect curvature associated with elastic pressurization of the conduits 18, the lever assembly 30 is pivoted in a counterclockwise sense as illustrated in FIG. 9 to open ball valve 42. This closes vent 43 and imparts high pressure from the chamber 62 through the valve 42 to the line 20. No simultaneous pressure is provided to the conduit 18. The high pressure in conduit 20 actuates check valve 70 in FIG. 7 to permit fluid flow to the conduit 20 in segment 14. This results since pressure in chamber 62 exceeds pressure in chamber 64 causing valve 70 to switch to the high pressure source. To effect the opposite curvature, the lever assembly 30 is pivoted in the clockwise direction. This actuates the ball valve 40 and closes vent 41. Valve 42 closes and vent 43 opens. Conduits 19 and 21 are similarly controlled with respect to the use of ball valves and the like. In this manner it is possible to effect complete control of the rigidity and curvature of a segment of the endoscope tube 10. Such a lever assembly is typically provided for each segment 14 of the endoscope. In practice, only one or two lever assemblies need to be utilized inasmuch as only one or two segments 14 will be needed in order to guide an endoscope tube 10 appropriately into position. The pressure in the chamber 64 is also preferably variable in order to adjust the rigidity of the segments 14 as determined by the pressure within each of the separate conduits 18-21. In sum, lever 30 controls curvature. Flexible rod 52 controls rigidity. Rigidity requires low pressure relative to the higher pressure curvature control. It is possible to vary the construction of the invention in numerous ways. For example, each of the separate segments 14A, 14B and 14C may be connected to a separate control mechanism for purposes of controlling rigidity. Each of the separate control mechanisms can be adjustable to provide various levels of pressurization of that separate segment. With increased pressurization of a segment, there is increased rigidity. It is also possible to interconnect the conduits 18-21 of separate segments 14A-14C by means of threshold check valves. Thus, the segments 14A-14C will be sequentially pressurized as increasing thresholds of pressure are reached. Yet a further alternative construction would provide for use of a single control mechanism which could connect to any one of the separate segments 14A, 14B, 14C, etc. The connection to each of the separate segments 14A, 14B, 14C, etc. is controlled by a selector switch. As a further feature of the invention, an elastic distal end segment may connect to one or more of the conduits 18-21. The distal end segment can then be inflated and function as a dilator to help advance movement of the endoscope into a body canal or cavity. Further, the invention can be constructed so that the conduits 18-21 are always equally pressurized to merely provide a means to render the segments 14 rigid. Also, separate means such as known to those of ordinary skill in the art can be used to control the curvature of the segments 14 or tube 10. For example, it is known to use various wire control systems which mechanically operate to curve the tube 10. Such a mechanical system can be used in combination with the conduit system of the present invention. Yet another option is to provide alternate means for venting the conduits 18-21 whenever the associated valve connecting that conduit to a pressure source is released. It is also possible to vary the construction of the conduits. That is, an accordion-type cross section has been disclosed. However, the cross sectional shape, size and configuration of the conduits, for example conduit 18, may be varied in accord with desires to achieve various types of control upon inflation as well as upon the elastic deformation. Further, the number of conduits used in each segment may be varied. The number of control segments can be varied. The particular arrangement of the conduits relative to the center line axis of the tube can be varied. The choice of materials can be varied. The interconnection or interrelationship of the conduits 18-21 to the tube 10 can be varied. The conduits may be, for example, integrally molded or formed in the tube 10. Alternatively, the conduits may be made of a separate material having distinct elastic and plastic characteristics relative to the material used to form the tube 10. Though a toggle stick or joy stick mechanism for controlling pressure to each of the separate conduits is disclosed, numerous other types of control mechanisms are possible to vary the pressure to each of the separate conduits in each of the separate segments. Thus, while there has been set forth a preferred embodiment of the invention, it is to be understood that the invention is to be limited only by the following claims and their equivalents.	An improved flexible endoscope of the type which includes a hollow elongate flexible tube having a distal end which is inserted into a body cavity and a proximal end which is external the body. A sensor system extends through the flexible tube from the proximal end to the distal end. The sensor system is capable of transmitting diagnostic information from the distal end to a sensor system at the proximal end. Means for controlling the flexure of each tube comprises at least one longitudinal expandible conduit positioned radially with respect to the center line axis of the segment. In a preferred embodiment a plurality of inflatable and expandible conduits are provided and pressure means is also provided to inflate the conduits to control rigidity or to expand the conduits longitudinally and sequentially in order to vary the curvature of the tube.	0
SUMMARY OF THE INVENTION The present invention relates generally to a method and apparatus for removing feathers and down from a fowl and more specificaly to a rotating drum of flailing members positioned within a venturishaped housing containing a means for generating an air flow within the housing and exhausting such flow and removed feathers and down out the smaller end of the venturi housing in response to the pressure differential and air flow velocity differential created within the venturi. The housing is enclosed such that the removed feathers and down are not strewn about, and such that the odor of fowl feathers does not permeate the operator's work area. The use of a rotating drum having radially extending rubber fingers is not new to the art, as is shown by Campbell U.S. Pat. No. 2,376,120, Zebarth U.S. Pat. No. 2,908,033 and Pitts U.S. Pat. No. 2,777,159. Each of the aforementioned devices incorporates no adequate means of collecting the feathers once removed from the fowl. Other devices incorporate suctions fans or the like for this purpose with the effect of unnecessarily channelling removed feathers through the suction mechanism or fan. None of the prior art devices incorporate a means whereby an operator could manually position the bird adjacent the feather removing device in order to observe and more effectively perform the feather removing operation, and also a means for exhausting the removed feathers, and the odor therefrom, away from the operator and into a suitable receptacle. It is therefore an object of the present invention to provide a device which permits the operator to manually hold a fowl during the feather plucking operation, thereby obtaining optimum cleaning thereof. It is a further object of the present invention to provide an enclosed housing which precludes loose feathers, and the odor therefrom, from being strewn about and permeating the air around the operator. It is a further object of the present invention to utilize a venturi-shaped housing and a blower to create an air flow to collect removed feathers and exhaust them, and the odor therefrom, into a suitable receptacle without passing the feathers through the suction mechanism or fan. BRIEF DESCRIPTION OF THE DRAWING Other objects and advantages of the invention will become apparent upon a careful reading of the following detailed description of the invention, the claims and the drawing, in which like reference characters are used throughout to denote like parts, wherein: FIG. 1 is an isometric view of the feather plucking device. While the invention will be described in connection with a preferred embodiment, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims. DETAILED DESCRIPTION OF THE INVENTION Turning now to the drawing, the feather plucking device is shown generally illustrated at 10, comprising a housing 12, an internal rotatable means or drum 30 for removing feathers from a fowl, and an air flow generator 42 for directing the removed feathers out of the housing. The housing 12 comprises a large section 14 and a small section 16 formed by a right tapered side wall 18, a left tapered side wall 20, a tapered top 22 and a tapered bottom 24. Located at the end of the small section 16 is discharge orifice 28 through which removed feathers are ejected into an appropriate receptacle (not shown). The air flow generator 42 comprises an internal curved deflector or direction tunnel 44, an external cylinder fan 46 and an electric motor 48. As shown in the drawing, the curved deflector 44 directs the air flow from the fan 46 to the discharge orifice 28, and works with the housing 12 to create a flow of air from the larger section 14 to the smaller section 16 thereof. The preferred embodiment of the housing 12 comprises 4 tapered walls 18, 20, 22 and 24, that form a venturi-shape to the housing 12. The venturi housing 12 works with the air flow generator 42 to create a flow of air from within the large section 14 through the small section 16 and out the exit discharge orifice 28 at the smaller end thereof. From a simple knowledge of fluid flow through a venturi-shaped tunnel, it is readily appreciated that this flow of air at a given initial velocity is accompanied by a decrease in static pressure proportional to the increase in fluid velocity through the venturi. Air flow through the large section 14 of the housing 12 is at a substantially lower initial velocity, thereby giving rise to a higher pressure differential between the large and small sections, 14 and 16, respectfully. This higher velocity and corresponding lower pressure through the small section 16 combine to draw loose feathers removed in the large section 14 through the small section and out the discharge orifice 28 into a bag or other suitable receptacle (not shown) for collection. Means is provided for removing the feathers and down from a duck or other fowl, comprising a rotatable means or drum 30 positioned within the large section 14 of the housing 12 and adapted to rotate along its center cylindrical axis transverse to the flow of air within the housing. This rotatable means 30 includes a plurality of flailing members or fingers 32 extending radially outwardly therefrom for removing feathers from the bird. These flailing fingers 32 are sufficiently resilient to support their own weight and remove feathers and down from a fowl held in close proximity therewith as the rotating drum 30 rotates about its axis, yet are sufficiently flexible to yield to the body of the fowl to prevent bruising or scratching the body as the feathers are being removed. In the preferred embodiment, these flailing fingers 32 are constructed of a soft rubber having a significant friction effect upon the bird feathers in order to "grasp" and "jerk" the feathers straight out from the bird, as opposed to bending, and chance breaking, the feathers during removal. The rotatable drum 30 is driven by an electric motor 40 at a rate to sufficiently remove all feathers and down from the fowl without bruising the bird or injuring the operator's hand, should it come in contact with the rotating flailing fingers 32. The venturi-shaped housing 12 includes a large section end or door 26 that prevents feathers and down from flying about in the room as the operator de-feathers his catch. It will also be appreciated that the closed housing 12 restricts, if not totally precludes, the foul odor of fowl and feathers from permeating the operator's work area. This large section end 26 includes access passageways 50 covered by restrictive means 52 which permit air to flow into the large section 14 around the operator's forearms and elbows, but is so designed to prevent feathers and down from escaping through the access passageways 50. In the preferred embodiment, this restrictive means 52 is in the form of a rubber sleeve which gives the operator sufficient freedom of movement to manipulate a duck or fowl inside the housing 12 from without the housing in order to more efficiently remove feathers and down from the bird. The preferred embodiment includes a window 54 mounted with the large section end door 26 permitting the operator to observe the fowl as he manipulates same within the feather plucking housing 12 to de-feather the bird. The door is mounted by hinges 56 or any other suitable means permitting the operator to open the door and insert a fowl in the housing 12 and then close the door while holding the fowl in one of his hands extended through an access passageway 50 into the large section 14 of the housing. The preferred embodiment also includes a light 56 located in a manner so as to illuminate the interior of the large section 14 to permit the operator to more easily observe the bird held within. In operation, the operator opens the large section end door 26 slightly while inserting one hand and forearm through an access passageway 50 therein. He next places the bird to be de-feathered in the hand within the housing 12 and closes the door. By activating a switch, he simultaneously supplies electric current to the air flow generator motor 48, the rotatable drum motor 40 and the interior light 58 to turn the system 10 on. As the drum 30 rotates, the flailing fingers 32 slap at the bird held within the housing to remove the feathers and down from the bird and initially direct them toward the smaller section 16 of the housing. The air flow generator 42 creates a pressure differential between the large and small sections 14 and 16 so that the lower pressure and increased air flow velocity within the smaller section operate to suck loose feathers and down from the large section, through the small section and out the discharge orifice 28. The window 54 permits the operator to observe the fowl within and to use human judgement and dexterity to manually, by mechanical assistance, remove the feathers and down from the bird without bruising or otherwise injuring the meat on the bird. When the operator determines that the bird has been sufficiently cleaned, he turns off the electric power to the device, opens the door 26 and removes the bird therefrom. Alternatively, the operator can open the door 26 first and remove the bird while the air flow generator 42 continues to evacuate the interior of the housing 12. The blast of air through the housing caused by the sudden opening of the door 26 collects any loose feathers and down within the housing and blows them out the discharge orifice 28 into a suitable receptacle for collection. From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the apparatus. It will be understood that certain features and subcombinations are of utility and may be employed with reference to other features and subcombinations. This is contemplated by and is within the scope of the claims. As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.	A device for removing feathers from a fowl utilizing a rotating drum having radially extending flailing members, enclosed within a venturi-shaped housing having a fan for creating a flow of air to collect and exhaust the removed feathers out the smaller end thereof. The device permits the operator to manually position the fowl against the feather removing means from outside the device, thereby precluding removed feathers, and the odor therefrom, from permeating the air about the operator.	0
RELATED APPLICATION DATA This application claims the benefit, pursuant to 35 U.S.C. §119(e), of U.S. provisional application Ser. No. 60/918,632, filed Mar. 19, 2007. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to anti-suicide articles of clothing and relates particularly to an anti-suicide article of clothing that is comfortable to wear, yet prevents a user from using the article to commit suicide. 2. Description of Related Art In prisons and jails there is always a percentage of inmates that need to be kept isolated from other inmates (e.g., solitary confinement) for a variety of reasons such as punishment for certain types of crimes, bad behavior, contagious illness, the tendency to fight with other inmates, etc. Similarly, patients of mental health facilities may be dangerous to themselves and other patients or the facility staff and need to be kept in isolation for extended periods of time. In these scenarios, there exists the possibility that inmates and patients, respectively, may have severe anxiety, depression, or even suicidal tendencies. In such cases, these individuals may attempt to make use of their clothing (or parts thereof) to hang themselves. 2004 statistics show that in the U.S., death by hanging, strangulation, or suffocation is the second most common method (after firearms) for a person to commit suicide, with 22.4% of suicide victims having committed suicide by the former method. In an effort to prevent a user (e.g., inmate, patient, etc.) from using his clothing to hang himself, the users are issued special protective clothing (e.g., clothing that is tear resistant). A current fabric used to manufacture protective clothing consists of a high strength nylon shell sewn together with nylon thread. A drawback of items made from this material is that they feel rough against the skin of the wearer and are thus extremely uncomfortable for the inmate or patient. When articles of clothing constructed from this material are worn for relatively long periods of time, the discomfort caused by the use of these items often increases the agitation of the at-risk individual, potentially further compromising the mental state of the inmate or patient. One type of existing clothing available for wear by individuals with suicidal tendencies is an isolation smock or safety smock. These garments are sometimes constructed of material of a one-piece design with no sleeves. This is because sleeves can either be tied together to create a rope or used individually as a noose. To prevent tearing, the smocks often are made of a material that is tear-resistant, such as nylon or polyester. Because the smocks are manufactured for strength, not comfort against the user's skin, the wearer of such a smock will often complain to medical personnel, prison guards, or facility staff, as appropriate. Accordingly, there is a need for an anti-suicide article of clothing that overcomes the aforementioned drawback, that is comfortable to wear, and cannot be used to commit suicide. SUMMARY OF THE INVENTION The present invention provides a comfortable article of clothing that can be worn by inmates and medical patients, wherein there is a danger of suicide or self-injury by such persons. In one embodiment, the article of clothing is comprised of a high-strength fabric consisting of an outer layer of tear-proof, high strength natural or synthetic material and an inner layer of soft natural or synthetic material. Between the inner and outer layers of material is sandwiched a third layer of insulating material to provide warmth and additional bulk to the fabric. The three materials are joined together with a nylon thread stitched in a pattern. In one embodiment of the present invention, the article of clothing is a smock. The smock provides strength, warmth and comfort for suicidal inmates and patients. The smock further comprises at least one sleeve section that is removably attached to a torso section, wherein at least one sleeve section breaks away or detaches from the torso section at least in part when a user pulls at least one sleeve section away from the torso section. For example, in one embodiment of the present invention, at least one sleeve section can be completely removed from the torso section when a user pulls the at least one sleeve section away from the torso section. In another embodiment of the present invention, the at least one sleeve section only partially breaks away (or detaches) from the torso section. In another embodiment of the present invention, the article of clothing is comprised of a material that has less than a few ounces of tensile strength, thereby preventing the user from injuring or killing himself with the article of clothing. In one embodiment of the present invention, the article of clothing is an undergarment. In this embodiment, the undergarment further comprises at least one layer of synthetic or cellulose material with waist and leg openings and is disposable. The undergarment can utilize a single-strand of elastic thread around the waist and leg openings for a snug fit around the user's body. In a variation of this embodiment, the undergarment is comprised of at least one layer of the synthetic or cellulose material in an approximately rectangular shape having no openings. The undergarment is folded around the portion of the body of the user, wherein a first side and a second side of the material are fastened together by a plurality of removable fastening devices. In another embodiment of the present invention, there is provided an article of clothing for suicide prevention, comprised of an outer layer, an inner layer, a middle layer between the inner and outer layers, and a nylon thread material for holding the outer, inner and middle layers together. The outer layer consists of a polyester material that has a weight of greater than 300 denier and is tear-resistant, thereby preventing the user from tearing the outer layer into strips and using the strips to construct a rope for committing suicide. In contrast, the inner layer consists of a cotton material that is greater than 7.2 ounces, while the middle layer consists of polyester fiberfill material that is greater than 2 ounces. In another embodiment of the present invention, there is provided an article of clothing for suicide prevention, comprised of a torso section, at least one sleeve section, and a plurality of relatively short-length removable fastening devices connecting at least in part the at least one sleeve section to the torso section. The torso section covers at least a portion of the user, while the at least one sleeve section covers at least a portion of at least one arm of the user. A plurality of relatively short-length removable fastening devices are preferably used instead of a single relatively long removable fastening device. This is because a single relatively long removable fastening device can be used (itself) to form a rope for committing suicide. In another embodiment of the present invention, there is provided an article of clothing for suicide prevention. The article of clothing includes a plurality of openings and consists of a non-woven material, nylon thread for stitching the non-woven material together into a shape and a single elastic thread attached to the non-woven material at each one of the plurality of openings. The non-woven material is relatively weak, thereby allowing a user to tear the non-woven material into strips and to use the strips to construct a rope, but preventing the user from using the rope to commit suicide (due to the strength (or lack thereof) of the non-woven material). The shape of the non-woven material allows the article of clothing to cover a portion of a body of the user. The single elastic thread is adapted to prevent the non-woven material from falling off of the portion of the body of the user. In yet another embodiment of the present invention there is provided an article of clothing for suicide prevention. The article of clothing consists of a non-woven cellulose material, nylon thread for stitching the non-woven cellulose material together into a shape, and a plurality of removable attachment devices at a plurality of opposing ends of the article of clothing. The non-woven cellulose material is relatively weak, thereby allowing a user to tear the non-woven cellulose material into strips and to use the strips to construct a rope, but preventing the user from using the rope to commit suicide. The shape of the non-woven material allows the article of clothing to cover a portion of a body of the user. The plurality of removable attachment devices are adapted to affix a plurality of opposing end portions of the article of clothing around the portion of the body of the user. A more complete understanding of the anti-suicide garment will be afforded to those of skill in the art, as well as a realization of additional advantages and objectives thereof, by a consideration of the following detailed description of a preferred embodiment. Reference will be made to the appended sheets of drawings which will first be described briefly. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front perspective view of an anti-suicide smock with break-away sleeves in accordance with one embodiment of the present invention, when viewed from the front. FIG. 2 is a side perspective view of a multi-layered swatch of fabric used to construct the smock illustrated in FIG. 1 in accordance with one embodiment of the present invention. FIG. 3 is a front perspective view of an article of clothing for suicide prevention in the form of an undergarment in accordance with one embodiment of the present invention. FIG. 4 is top perspective view of an article of clothing for suicide prevention in the form of an adult diaper in the open position in accordance with one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention provides a comfortable article of clothing that can be worn by inmates and medical patients, wherein there is a danger of suicide or self-injury by such persons. One advantage of such an article of clothing is that the wearer is kept warm and maintains some dignity by being covered with a fair amount of comfortable clothing, but is unable to destruct the clothing in such a way as to be used to construct a rope or a noose. The invention thereby overcomes the drawbacks of the prior art. The following embodiments of the invention describe elements comprised of particular materials, as well as describing particular types of fastenings that are illustrative only. These embodiments are not to be considered limiting in any respect. In the detailed description that follows, like element numerals are used to indicate like elements appearing in one or more of the figures. FIG. 1 is a front perspective view of an anti-suicide smock 100 with break-away sleeves or sleeve sections 112 and 114 in accordance with one embodiment of the present invention, when viewed from the front. The smock 100 provides warmth and dignity to a user and can easily be manufactured in different sizes to fit users of differing heights and girth. The smock 100 is comprised of a torso section 110 that covers at least a portion of a torso of a user, at least one sleeve section 112 or 114 , and a plurality of interlocking removable fastener devices 120 - 142 . In a preferred embodiment, the smock 100 contains both sleeve sections 112 and 114 ; however, the smock 100 can be constructed with just one of sleeve sections 112 and 114 , for situations such as a one-armed user or where the user currently has one arm in a splint or cast. The smock 100 is further comprised of a left portion 150 , a right portion 152 , a neck opening 105 , a torso flap 144 , sleeve flaps 116 and 118 , as well as sleeve flaps 156 and 158 . The removable fastener devices 120 - 142 each are comprised of at least two of a plurality of interlocking components that are placed on opposing sides of the portion of the smock 100 . In a variation of this embodiment, the removable fastener devices 120 - 142 are each comprised of a single interlocking component that is adapted to be placed on a single side of the smock 100 , wherein the interlocking component directly adheres or mates with the surface of the material that comprises the smock 100 . The removable fastener devices 120 - 142 serve several purposes. First, the removable fastener devices 136 - 142 that are placed along the torso flap 144 connect the left portion 150 to the right portion 152 . Second, the removable fastener devices 120 - 124 connect the sleeve flap 156 to the left portion 150 and similarly, the removable fastener devices 128 - 132 connect the sleeve flap 158 to the right portion 152 . The removable fastener device 126 connects the sleeve flap 116 attached to a front portion of the sleeve section 112 to a back portion of the sleeve section 112 . Similarly, the removable fastener device 134 connects the sleeve flap 118 attached to a front portion of the sleeve section 114 to a back portion of the sleeve section 114 . A key use of the plurality of interlocking removable fastening devices 120 - 142 versus having a single removable fastening device along the entire length of each removably attached portion of the smock 100 is to prevent the user from separating such a relatively long removable fastening device from the smock 100 and fashioning the removable fastening device into a rope or a noose to hang himself. For example, if removable fastening devices 128 , 130 , and 132 were combined into one long fastening device (not shown) to effectively join the entire first portion of the sleeve flap 158 to the right portion 152 , the user could possibly tear away the one long fastening device from the first portion of the sleeve flap 158 and use the device to construct a rope or a noose. Another key use of devices 120 - 134 , however, is to provide break-away sleeve functionality to prevent the user from forcing his head into the sleeve section 112 or 114 in an attempt to hang himself. Other anti-suicide smocks in existence specifically do not have sleeves (let alone break-away sleeves) to prevent the user from attempting to injure himself in this manner. More specifically, if existing anti-suicide smocks had large diameter rigidly attached sleeves, the user could attempt to hang himself with such a smock by tying a portion of such a smock to a relatively fixed or heavy article of furniture or a sturdy fixture in the user's cell or room, putting his head in one of the sleeve openings, and using his own body weight to hang himself. The break-away sleeve sections 112 and 114 of the present invention prevent the user from hanging himself in such a manner. That is, the sleeve sections 112 and 114 can partially break-away from the left portion 150 and the right portion 152 , respectively. In particular, the sleeve flaps 156 and 158 will open and unroll away from the torso section 110 when a user attempts to injure himself in by pushing his head into the proximal ends of the sleeve sections 112 or 114 via the interior side of the torso section 110 , causing removable fastener devices 120 - 124 and 128 - 132 , respectively, to release a first portion of the sleeve flaps 156 and 158 . In a variation of this embodiment, the sleeve sections 112 and 114 can have relatively large diameters that allow the user to easily place his head inside the interior of the sleeve sections 112 or 114 . If the user ties off a portion of the smock 100 to a relatively fixed article of furniture or a fixture in his cell or room and then attempts to apply his own body weight against the smock 100 in an effort to hang himself, the removable fastener devices 120 - 124 and 128 - 132 , respectively, will release the first portion of the sleeve flaps 156 and 158 . Similarly, if the user attempts to push his head into either of the open ends of the sleeve sections 112 or 114 that are distal from the torso section 110 , removable fastener devices 126 and 134 , respectively, will release a second portion of the sleeve flaps 156 and 158 . As the user proceeds to push his head deeper into the opening in the sleeve sections 112 or 114 , additional removable fastener devices 120 - 124 and 128 - 132 , respectively, will release the first portions of the sleeve flaps 156 and 158 . The sleeve sections 112 and 114 are illustrated as being relatively short, like a short-sleeve t-shirt, to prevent the user from tying the sleeves 112 and 114 together to form a rope that can be used to injure or kill the user. One of skill in the art will appreciate that the sleeve sections 112 and 114 can also comprise longer length sleeves. In a variation of this embodiment, there are additional removable fastening devices (not shown) attached to the rear portion of the sleeve sections 112 and 114 so that the entire sleeve sections 112 and 114 can be completely removed from the torso section 110 when the user pushes his head into the opening of the sleeve sections 112 or 114 . In a preferred embodiment, the removable fastener devices 120 - 142 are comprised of hook-and-loop fasteners (e.g., Velcro™ fasteners, licensed or manufactured by Velcro Industries B.V. Ltd. Liability Co., Netherlands). Hook-and-loop-type fastener systems are comprised of a pair of complementary surfaces, generally available in strip or pad form. One of the strips or pads is provided with a hooked surface, and the mated strip or pad is provided with a looped surface. Once the complementary strips or pads are placed in mated juxtaposition and a light pressure is applied, they form a mechanical bond and provide a strong, semi-permanent closure which may be opened by removing, in sequence, a small portion of the hook and loop bond, preserving the system for reuse. One of skill in the art will appreciate that other types of removable fastener devices 120 - 142 such as the use of snap fasteners that are comprised of a pair of interlocking discs or the use of buttons and opposing buttonholes or reinforced slits that utilize thin breakable thread are also within the spirit and scope of the present invention. FIG. 2 is a side perspective view of a multi-layered swatch of fabric 200 used to construct the smock 100 in accordance with one embodiment of the present invention. The fabric 200 is similar to a quilt. The fabric 200 is comprised of an outer layer 205 , a middle layer 210 , an inner layer 220 , and thread 225 that holds together the outer layer 205 , the middle layer 210 , and the inner layer 220 . The outer layer 205 is comprised of highly tear-resistant woven materials like polyester or nylon. The outer layer 205 can also be comprised of other materials such as those commonly used to construct parachutes and can include a low-stretch Dacron™ or zero-stretch Spectra™, Kevlar™, Vectran™, as well as high-modulus aramids. The tear-resistant property of the outer layer 205 prevents the user from tearing the outer layer 205 into strips and using the strips to construct a rope for committing suicide. In a preferred embodiment, the outer layer 205 is comprised of a polyester material that is greater than 300 denier in weight; preferably 600 denier, though one of skill in the art will recognize that different weights and types of materials can be utilized within the spirit and scope of the present invention. Due to the need for the outer layer 205 to be comprised of a strong tear-resistant material, the outer layer 205 is generally sensed as being hard and uncomfortable against the skin by the user, possibly causing chafing and rashes if the inner layer 220 were composed of the same material. The inner layer 220 is comprised of a soft material that is comfortable against the skin. In a preferred embodiment, the inner layer 220 is comprised of cotton material that in turn can contain 100% cotton material or a cotton blend material. In order to provide adequate strength and softness against the skin of the user, the cotton material 1 is of a weight of greater than 7.2 ounces and in a preferred embodiment weighs 8.5 ounces. One of skill in the art will recognize that the inner layer 220 can also be comprised of other weights and types of natural and synthetic materials and still remain within the spirit and scope of the present invention. The middle layer 210 serves as batting or an insulating material that adds bulk to the fabric 200 and allows the smock 100 to provide warmth to the user. To adequately accomplish this function, in a preferred embodiment, the middle layer 210 is comprised of polyester fiberfill of a weight greater than 2 ounces, though other weights and types of natural or synthetic fill materials can also be effectively utilized within the spirit and scope of the present invention. In a preferred embodiment, the middle layer is comprised of 4 ounce polyester fiberfill. The inner layer 220 , the middle layer 210 , and the outer layer 205 are fastened together by the thread 225 . The thread 225 is sewn into a pattern that for ease of manufacturing repeats and can form a multitude of particular shapes and patterns. Perhaps one of the easier to manufacture patterns is the diamond-like pattern illustrated in FIG. 2 , though of course other such patterns as squares or rectangles can be utilized as well. Further, the size of each recurring pattern section (e.g., the dimensions of each diamond) can vary. To provide durability and washability by commercial laundering methods, as well as to prevent the user from being able to tear apart the fabric 200 , a fairly heavy nylon thread of greater than 33 denier is utilized, and in a preferred embodiment, 69 denier nylon thread is utilized, though one of skill in the art will recognize that other weights and thread materials can also be effectively utilized within the spirit and scope of the present invention. FIG. 3 is a front perspective view of an article of clothing for suicide prevention in the form of an undergarment 300 in accordance with one embodiment of the present invention. The undergarment 300 is comprised of a crotch portion 344 , a left portion 340 , a right portion 342 , and a plurality of opening that comprise torso opening 330 and leg opening 320 and 310 . While conventional undergarments are comprised of natural or synthetic material such as cotton and can be laundered and re-used, the undergarment 300 is comprised of a thin, easily tearable, non-woven synthetic or natural material such as cellulose or, in a preferred embodiment, natural vegetable fiber that is comfortable for the user to wear and enables the undergarment 300 to be flushed down a municipal toilet for disposal after use. The body of the undergarment 300 can be made of a single layer of material or may be comprised of a plurality of layers in strategic areas such as the crotch portion 344 to prevent leakage. One of the physical properties of the undergarment 300 that is comprised of a single layer of non-woven cellulose material is that the material is relatively weak, thereby allowing the user to tear the undergarment 300 into strips and to use the strips to construct a rope or noose, but preventing the user from using the rope to commit suicide, since such a rope will tear when tensile stress is applied by the user. Thread (not shown) is utilized for stitching to form the material into the shape of the undergarment 300 that can cover a portion of the body of the user, though the undergarment 300 can have different shapes to accommodate users of differing size and weight. In a preferred embodiment, the thread is comprised of nylon thread. Stitched areas 346 and 348 located on the left portion 340 and the right portion 342 , respectively, connect a second layer of material that is attached to the undergarment 300 to form the crotch portion 344 that helps prevent leakage. Unlike conventional undergarments, there is no fly area that opens to allow the user to urinate without removing the undergarment 300 from the user's torso. This is to prevent the user from being able to tear away the material that would form a fly area and fashioning a rope. In another embodiment (not shown), there is no second layer of material connected to the left portion 340 and the right portion 342 , and thus no stitching 346 and 348 utilized in the undergarment 300 . The edges of the undergarment 300 surrounding the plurality of openings 330 , 320 , and 310 are comprised of a single elastic thread attached to the non-woven material at each of openings 330 , 320 , and 310 . The single elastic thread at openings 330 , 320 , and 310 is fashioned into elastic edges 332 , 336 , and 334 , respectively. Elastic edges 332 , 336 , and 334 prevent the non-woven material from falling off the appropriate portions of the body in contact with the undergarment 300 (i.e., the waist area and the tops of the user's legs). The elastic edges 336 and 334 also form a loose seal against the user's upper legs that help to prevent any leakage that might otherwise occur from an accidental urination or bowel movement for a short period of time. Unlike conventional undergarments, the elastic edges 332 , 336 , and 334 are very thin and small and the undergarment 300 does not have a waistband in the conventional sense. This serves to prevent the user from tearing the elastic edges 336 , 334 , and 332 away from the undergarment 300 and fashioning them into a rope with sufficient tensile strength for the user to form a noose or asphyxiate himself using the single elastic thread that comprises the elastic edges 336 , 334 , and 332 . One of skill in the art will recognize that the elastic edges 336 , 334 , and 332 can be comprised of a variety of types of elastomeric material other than natural or synthetic rubber. In a variation of the embodiment (not shown), the undergarment 300 has pleats or folds of the cellulose material that attaches to the elastic edges 336 , 334 , and 332 to help form the thin weak single layer of material into the shape of the undergarment 300 . FIG. 4 is top perspective view of an article of clothing for suicide prevention in the form of an adult diaper 400 in the open position in accordance with one embodiment of the present invention. The diaper 400 is comprised of a body 405 , a front section 410 , and a rear section 412 . Conventional diapers are primarily worn for incontinence reasons and/or uncontrollable bowels and are comprised of thick absorbent materials. The purpose of a conventional diaper is to absorb moisture and contain mess so that the user can remain dry and comfortable after wetting or soiling himself through a bowel movement or urination. Conventional diapers include cloth diapers that are comprised of layers of fabric such as terry toweling and can be washed and reused multiple times, as well as disposable diapers that contain absorbent chemicals and can be thrown away after use. Often, to avoid leakage of liquid or solid waste, plastic pants or other forms of diaper covers are worn externally over the conventional diaper by the user. In contrast, the diaper 400 is intended to be worn by a user that is capable of utilizing a toilet or restroom and does not require the bulk, level of absorbency and anti-leakage properties of the conventional diaper or plastic pants. The body 405 is comprised of a thin, easily tearable, non-woven synthetic or natural material such as cellulose, or in a preferred embodiment, natural vegetable fiber that is comfortable for the user to wear and enables the diaper 400 to be flushed down a municipal toilet for disposal after use. The body 405 can be made of a single layer of material or may be comprised of a plurality of layers in strategic areas such as the crotch area to prevent leakage. One of the physical properties of the diaper 400 that is comprised of a single layer of non-woven cellulose material is that the material being relatively weak, allows the user to tear the diaper 400 into strips and to use the strips to construct a rope or noose, but prevents the user from using the rope to commit suicide, since such a rope will tear when tensile stress is applied by the user. Thread (not shown) may be utilized for stitching to form the material into the shape of the body 405 that can cover a portion of the body of the user, though the body 405 can from different shapes to accommodate users of differing size and weight. In a preferred embodiment, the thread is comprised of nylon thread. In order to enable the diaper 400 to be worn around the portion of the body of the user, the diaper 400 contains a plurality of interlocking removable attachment devices affixed to front corners 414 and 416 with opposing interlocking components affixed to rear corners 420 and 418 , respectively. The removable fastener devices 422 - 428 each are comprised of at least two of a plurality of interlocking components that are placed on opposing sides of the front corner 414 and the rear corner 420 and the front corner 416 and the rear corner 418 , respectively. The removable fastening devices can be comprised of hook-and-loop fasteners (e.g., Velcro™), snaps, tape, stiff foldable tabs, or the like. Having thus described a preferred embodiment of anti-suicide articles of clothing, it should be apparent to those skilled in the art that certain advantages of the invention have been achieved. For example, the anti-suicide smock with break-away sleeves that prevent the user from forcing his head into one of the plurality of sleeve sections to suffocate himself has been illustrated, but it should also be appreciated that various modifications, adaptations, and alternative embodiments thereof may be made within the scope and spirit of the present invention. The invention is further defined by the following claims.	An article of clothing that can be worn by suicidal inmates and medical patients is provided. In one embodiment, the article of clothing is comprised of a high-strength fabric consisting of an outer layer of tear-proof material, an inner layer of soft material, and a third layer of insulating material between the outer and inner layers that provides warmth and bulk to the fabric. The three layers are joined together with a nylon thread. The article of clothing is further comprised of at least one sleeve section that is removably attached to at least in part to a torso section, wherein the at least one sleeve section detaches from the torso section to prevent a user from injuring or killing himself. In another embodiment, the article of clothing is comprised of a non-woven cellular material with very low tensile strength that cannot effectively be fashioned into a rope or noose.	0
FIELD OF THE INVENTION [0001] The present invention pertains generally to security systems for processing large numbers of people in which the people are given an opportunity to self-organize into various different risk categories. BACKGROUND OF THE INVENTION [0002] Terrorism has become a recent concern, such as suicide hijackers who might use commercial aircraft to deliberately crash into civilian targets. The damage that can be done by a person taking control of a commercial aircraft is immense not just because the kinetic energy of a modern commercial aircraft can be on the order of 2.5 Giga joules, but, that the aircraft might have large quantities of fuel on board, essentially turning it into a life threatening missile. [0003] While metal detectors may be used to detect weapons such as guns and small knives, terrorists will likely find ways to circumvent these measures, especially if they are on a suicide mission. [0004] For example, with the advent of bioterror, the possibilities of smuggling anthrax, or disease onboard an aircraft is not checked by metal detectors. The attacker could even deliberately infect himself or herself with a serious disease, and travel to the target country. In this instance the terrorist carries the disease within his or her body. [0005] Increasing the mandatory screening of passengers simply increases the delay, and at the same time, passengers often feel indignant to mandatory scrutiny. SUMMARY OF THE INVENTION [0006] There are many activities and experiences that persons are willing or even eager to undergo by their own free will, but unwilling (and even horrified) to undergo by force. One example of such an experience is sexual intercourse. Persons are horrified at being forced to undergo such an experience to the extent that severe penalties are imposed on the perpetrators of such force. It is not the activity itself (e.g. sexual intercourse) that is horrible, but, rather, it is the loss of control that the individual experiences over their own personal dignity and personal space. [0007] When the control over someone's personal space is violated, the results are often devastating by way of a psychological trauma that far exceeds the actual physical damage. [0008] Even an unsuccessful or incomplete rape, such as when a victim's clothing is stripped away, but nothing more is done to the victim, can have lasting psychological damage to the victim. [0009] Strip searches often fall into this category, in the sense that they often result in severe psychological damage. Indeed strip searches are often used as part of the torture that political prisoners are subjected to. [0010] Mandatory strip searches at airports are often the cause of major lawsuits in the millions of dollars. However, the same people filing such lawsuits have most likely, at some time in their life, voluntarily undressed in the presence of other people. Communal showers are quite common in athletic facilities, health clubs, and municipal swimming baths. Moreover, many people are willing to pay to use a facility where they are required to undress in the presence of others. For example, while using a luxury spa facility having steam rooms, saunas, whirlpool baths, and the like, users voluntarily remove their clothing. [0011] A person may also be willing to undress in order to undergo a medical examination. The subject of such an examination may also be willing to undergo blood tests, and other invasive tests that reveal personal information and confirm the absence of a disease. Being free of disease and being willing to prove that one is free of disease (or at least being willing to submit to screening) is of great value to society as a whole. Thus, by willingly making a bodily information, disclosure, the subject has bestowed a benefit upon society. Therefore, a method of doing business in such disclosure may include a method of allowing the subject (the disclosee) to benefit, at least partially, from making the disclosure. For example, the costs of the medical examination could be reduced or the medical examination could even be provided free of cost, in return for the benefits derived from knowing that the subject is disease free. Thus a passenger willing to submit to a quick and efficient medical screening exam could be provided with that exam free of cost, and could also be granted expedited boarding of the aircraft. Thus those willing to undergo such an exam could, for example, bypass the lineup at Customs and Immigration, or could receive non-suspiciousness index (NSI) points for the disclosure. Those formerly suspected of possibly carrying disease into a country could therefore voluntarily remove themselves from such suspicion, or at least reduce their level of suspicion, by submitting to a bodily information disclosure coupled to a suspicion decrementer. [0012] A person undergoing a medical exam will often undress to do so. If a person had explosives taped to his or her body, or was carrying a concealed handgun, or other contraband, it is less likely that such a person would take advantage of an offer for a free medical exam. Thus offering a free medical exam, a free checkup, or even a free body scan, could allow persons to self-organize into a low risk category and an unknown-risk category. If there was a free medical exam booth, and a person could skip the long lineup, or at the very least, hold their place in line but get a free medical exam during the time they would otherwise spend waiting in line, at least some persons would take advantage of such a program. The program could also be offered at very minimal cost, by using an automated “digitizing” scanning booth. At the same time as a person is examined, their clothing could be scanned or inspected. It is not necessary to examine the clothing of every volunteer subject, but only that there be the possibility that the clothing might be inspected. This possibility would keep terrorists from deciding to be subjects. [0013] When participating in activities, such as the use of a municipal swimming bath, that involve the removal of clothing, users get to maintain control over their clothing through the use of personal locks that the users bring to a locker room facility. However, in other situations, users are quite willing to lock their clothes into a locker that can obviously be opened by an attendent. For example, a sign in the men's locker room of the Alumni Pool at the Massachusetts Institute of Technology (MIT) reads “All non MIT locks will be cut off”. Students, staff, and faculty willingly strip naked in view of others, and then lock their clothes into lockers that have the potential to be inspected. In a sense these persons are willingly leaving themselves vulnerable to an inspection of their clothing and personal effects in their absence (e.g. while they are using the pool). [0014] MIT like many of the so-called “ivy league” colleges has a mandatory swim requirement in which a swim test must be completed in order to receive a graduation diploma. Although the swim test is trivial in difficulty, it does require the following: [0015] undressing in the presence of others; [0016] showering while completely naked, in the presence of others (a sign in the MIT alumni pool shower room reads “A thorough soap shower, without suit, must be taken prior to entering pool area”); [0017] being supervised while in a state of partial undress (e.g. wearing only “proper bathing attire”) by a person administrating the swim test; [0018] showering again; [0019] getting dressed in the presence of others. [0020] Ordinarily the swim test is administred over a two day period for most of the incoming freshmen, such that the above undressing and being naked in the presence of others takes place in a very crowded environment. [0021] When the applicant raised a privacy concern of the above procedure with MIT's student privacy representative (Amy Bruckman), the representative dismissed the concern as unfounded. [0022] It is possible that an organization such as the American Civil Liberties Union (ACLU) could address mandatory swim tests, in the manner in which mandatory showers in high school gym classes had been addressed by the ACLU: [0023] Students who dreaded showering at school got a lift two years ago after the American Civil Liberties Union threatened to file a lawsuit in Federal court over a mandatory shower policy in Hollidaysburg, Pennsylvania, the Times said. “Unless a student is drawing flies,” said David Millstein, the lawyer in the case, who represented a shy, overweight girl who felt humiliated in the showers, “It's none of the school's business.” The school district dropped its policy. But in the meantime, Mr. Millstein was deluged with calls and letters of support from people who remembered their own feelings of shame and embarrassment in the public showers. “In 25 years of doing ACLU work—cases on prayer in the school, you name it I had never had any response like this,” he said. [0024] Referenced New York Times, Jul. 25, 1998, cached in http://wearcam. org/envirotech/aclu_gym_showers2.htm [0025] Thus it appears that mandatory stripdown requirements of any sort are likely to come under attack, and are not likely to be well received. Thus mandatory stripdown situations appear to be declining. [0026] However, voluntary stripdowns appear to be on the rise, with growing numbers of persons joining athletic clubs, using communal spa facilities, and with increased body acceptance. While previously bombarded with television and advertising images of perfect bodies, we are now beginning to see a more typical “person next door” kind of look, that suggests an increased degree of body acceptance among a wider variety of members of the population. The proliferation of waterparks and leisure centers suggests that in the near future, ordinary people will feel comfortable in a bathing suit, while it is likely that terrorists trying to hide guns and knives in their loose (“baggy”) gang-style clothing will likely feel a little out of place in a waterpark, leisure center, or spa, especially if clothing storage means such as lockers have a key escrow feature. [0027] Many establishments reserve the right to inspect lockers, and., in that setting, users are still willing to use these facilities. Some waterparks, such as “Schwaben Quellen” (a member of European Waterparks Association) in Stuttgart require users to be completely naked except for a wristband which is a transponder that trackes the user's whereabouts throughout the park. [0028] Users do not appear to object to the idea of being required to be completely naked to use the spa facility, nor do they object to the idea of being required to wear a tracking device. They also do not object to the fact that their clothes are in a space that could be opened by waterpark officials without their knowledge. [0029] Moreover, users pay a fairly high user fee to use these facilities, and it is considered a luxury to have the privilege to strip naked and splash around in various baths, or the like. Many fine spa facilities have a locker room attendant who handles and keeps the clothing of spa visitors in a clothing check area. The tradition of having a human attendant hold onto the clothing and personal effects of bathers dates back to Roman times., and is often seen as a feature of a very upscale spa facility. [0030] To prevent the theft of clothing by staff, or by bath thieves, video surveillance is sometimes used. For example, the lockers at Blizzard Beach (a large waterpark in Florida) are overlooked by large video surveillance cameras. No effort has been made to hide the cameras, and it appears that such cameras make waterpark uses feel safe. Additional surveillance cameras throughout the facility capture images of bathers in a state of partial undress (e.g. wearing only a bathing suit) which does not appear to upset the bathers. Bathers continue to actually pay money for the privilege of stripping down and splashing around in the facility while being videotaped by security staff. [0031] It is doubtful that a terrorist with weapons and explosives taped to his or her body would use a waterpark, spa facility, or the like. [0032] Therefore, providing an opportunity to use some form of waterpark, spa, or other voluntary stripdown facility at a high security area such as an airport, would split the user population into two groups: [0033] personal disclosure participants who are very unlikely to be terrorists; [0034] personal disclosure nonparticipants who may or may not be terrorists. [0035] Those in the “personal disclosure nonparticipants” category are not necessarily terrorists. They might, for example, be “cyborgs” wearing a medical or prosthetic apparatus, wearable computer, or the like, or they could simply be persons who are adverse to getting wet. For example, a person who has spent a great deal of effort in terms of hair styling and makeup might not wish to get wet. [0036] Nonparticipants numbering N, together with M participants (men and women) will comprise a total population of M+N persons entering a secure area. The fraction M/(M+N) will comprise persons having a reduced need for suspicion and scrutiny because it is likely that this fraction of the population will represent a reduced risk. [0037] Risk costs. Processing a high number of high risk persons costs more, because additional security staff is required, further screening is needed, and there may be delays in lineup which cause further indirect costs. Such indirect costs include reputation costs, and goodwill costs, in terms of user satisfaction. [0038] The cost of reducing the security risk of a nonparticipant down to the same level as a participant can be quite high. For example, requiring a nonparticipant to undergo a strip search may give rise to an expensive lawsuit, and to a large delay. For example, suppose that participants have willingly stripped down, and are relaxing in a spa. Because the spa is an enjoyable experience that they wish to participate in, they strip down willingly, quickly, and without any problems. Nonparticipants selected for a strip search will present delays (undressing slowly and being uncooperative), and further costs later (lawsuits later on, bad feelings, bad publicity, etc.). [0039] Obviously not every nonparticipant will need to be strip searched, but consider some probability of strip search p for the total population. Without the use of the spa facility we would have p(M+N) strip searches to perform, at a cost of cp(M+N) where c is the cost per strip search. The cost c includes indirect costs, such as the cost of bad publicity, the cost of defending lawsuits, and other costs, as well as the actual cost of hiring staff to carry out the strip searches and to perform the screening necessary to decide who to strip search. In times of crisis consequence management, or in times of heightened security, it is quite possible that: cp ( M+N )> sM+cpN (1) [0040] or equivalently: cpM>sM (2) [0041] where s is the per-person cost of running the spa or other voluntary personal disclosure facility. In situations where Equation 1 is true, the costs of providing a spa for M people is less than the costs of providing strip searches for the fraction p of that same number of people. The cost savings, sM−cpM can be given back to the participants, in the form of subsidizing the spa treatments. [0042] In one embodiment a spa facility adjacent to or near to the airport is run by a private organization working together with the customs service, government, customs officials, and airlines, etc. Costs of spa treatments are subsidized by the savings to the airlines, and to the government, etc., in terms of reduction in costs resulting from the personal disclosures made by those using the spa. [0043] Spa users are pampered, and all the details are taken care of for them. Their luggage, and personal effects may be carefully and skillfully handled for them, and they may be taken directly onto the plane, in an express shuttle, so that they can board before any of the other passengers. Their carry on bags may be loaded onto the plane for them, so that they experience a nice service gesture in exchange for allowing a search of their carry on bags to take place while they are relaxing in the spa. In effect, they are pampered and cared for in return for submitting ot search. [0044] Participants receive a non-removable wristband as a status symbol to indicate their special status, and to track them while they are in a state of being partially or wholly undressed. Their ticket information, seat number, etc., with resect to the wristband, appears thereon, is encoded therein, or the like. [0045] It is quite possible that the cost savings are, or become, significant, in which case the use of the spa could actually be offered free of charge. Perhaps then, it would make sense to build the spa directly into the airport. A good place to build it would be a central place, such as where persons enter to clear customs. In this way, the voluntary disclosures made by participants could speed the participants through customs, as well as through airport security. [0046] The wristbands can encode and keep track of what facilities are used by the participant. As the participant uses more and more of the facilities, a “suspiciousness index” can be decremented. For example, suppose a participant strips naked, puts his clothes into a metal basket and hands the basked together with his luggage to a locker room attendant. That act alone reduces his suspiciousness index. The attendant can also gauge, based on personal experience, the demeanour and actions of the participant and award a certain number of points to the participant based on the facial expressions, and behaviour of the participant. Preferably the locker room attendant is a skilled customs official with many years experience in “reading” facial expressions. Stripped of clothing, eyeglasses, wearable computers, and other visual detritus, the participant is visible to the attendant, in a manner in which the attendant can see the true nature of the subject, the naked truth, and can make this truth of record. [0047] This record can be made by way of a wristband issuing station, in which, at this point, while the participant is standing naked at the clothing check-in area, the attendant issues a wristband. The act of entering a suspiciousness coefficient can be made covert by simply having the attendant hand the participant a wristband selected from several piles of wristbands, each pile having a certain suspiciousness coefficient already associated with it. BRIEF DESCRIPTION OF THE DRAWINGS [0048] The invention will now be described in more detail, by way of examples which in no way are meant to limit the scope of the invention, but, rather, these examples will serve to illustrate the invention with reference to the accompanying drawings, in which: [0049] [0049]FIG. 1 depicts an a disclosure pavillion sending data to a remote facility garden. [0050] [0050]FIG. 2 depicts a system with airport spa facility. [0051] [0051]FIG. 3 shows a wristband for use in an airport spa. [0052] [0052]FIG. 4 depicts an examination facility for allowing persons suspected of carrying disease to reduce their suspicion of being disease carrying or verminous persons. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0053] While the invention shall now be described with reference to the preferred embodiments shown in the drawings, it should be understood that the intention is not to limit the invention only to the particular embodiments shown but rather to cover all alterations, modifications and equivalent arrangements possible within the scope of appended claims. [0054] [0054]FIG. 1 is a diagram showing the operation of a disclosure pavillion having various exhibits. Each exhibit allows a person to choose to make a disclosure, if they wish to make such a disclosure. Rather than the specific lineup at an airport, or the like, the facility has a much more free atmosphere, in which persons can enjoy various exhibits in the disclosure pavillion. The exhibits can be visited in any order, and can be visited any number of times, including zero times for some of the exhibits if desired. [0055] The flowchart of FIG. 1 illustrates a particular ordering, which is in no way meant to limit the scope of the invention. An unknown participant who has never participated in any of the exhibits is said to have a Non-Suspiciousness Index (NSI) of zero, e.g. NSI=0. Initially, at the start 100 , such a person may choose to insert his or her ID card into a disclosure station. The station might offer free services, such as free Internet access, so that the person just uses their driver's license, or even a credit card, for identification purposes only, in order to “log on” to a computer terminal and to “surf” the world wide web for free. Preferably the participant is videotaped or video captured while doing this activity so that a remote facility garden can associate the name (on the ID card) with a face. The facility garden need not be located right at the disclosure pavillion, and in fact a single facility garden at a remote site, such as in the Far East, can monitor numerous disclosure pavillions. [0056] When the participant volunteers to be carded (e.g. uses an ID card to take advantage of a free service), the participant can receive targeted advertising tailored to their specific profile and interests. Thus at least a portion of the facility garden can be paid for by corporate sponsors who can run the exhibit that might, for example, preferentially direct users to their corporate web sites. A testing unit 101 checks to see if the user has volunteered, and if so, an NSI retriever 102 gets the previous NSI from the facility garden, and an NSI awarder 103 updates the participant's NSI. Now the participant has a higher NSI (e.g. a reduced suspicion), simply because he or she is no longer a stranger. [0057] Various exhibits in the pavillion have pushbuttons that are really also fingerprint scanners. For example, a pinball machine having two flipper buttons that are fingerprint scanners allows a participant to play a free game of pinball, while being fingerprinted many times. A videoorbits image consolidator makes a superresolution image of the subject's fingers over the course of the game. Cameras inside the pinball machine also scan the face of the player, so that the garden can match the print to the face. [0058] An automatcher 111 checks to see if a person is already in the garden; if the garden receives a print that is thus far unknown to it, an awarder 114 awards points to the subject as a first time enrollee. [0059] The public safety value in a person volunteering to be fingerprinted is, at least, in part, returned to the participant, by way of a free game, by way of expedited boarding, or a combination of these. Thus a person waiting to board an airplane can make a choice between, for example, a one hour wait in line, or a half hour game of pinball. Those choosing the half hour game of pinball board faster, and also enjoy the shorter waiting time because they can pass away this shorter time period playing a game of pinball. When a person plays, everyone benefits: the public benefit because the person has undergone a background check; the individual person benefits because at least some of the benefits to the public are reflected back to the individual player. Those who play the game are rewarded with faster boarding of the aircraft. [0060] Unlike traditional background checks, the garden adds a fun element to being fingerprinted. Although such a system could be used to conceal the fingerprinting (e.g. it could operate covertly), rather than conceal this operation, it is preferable that participants know that they are being fingerprinted, but be left with the ability to sustain an at least illusory notion of freewill. Thus rather than merely offer a person a chance to be fingerprinted to board the aircraft sooner, the person is offered a sweeter deal in which the fingerprinting is buried into something that is at least allegedly recreational or fun in some way. [0061] While it is true that a person could be offered a free cup of tea with sugar, as well as expedited boarding, for being fingerprinted, so that the cup of tea would take the role of this deal sweetener, the cup of tea is no more directly attached to the fingerprinting than is faster boarding of the airplane. Thus the pinball game is a deal sweetener that makes the being fingerprinted a concomitant activity. [0062] By making the fingerprinting concomitant to a recreational or leisure activity, the fingerprinting is made less confrontational to the subject. [0063] Moreover, the entire pavillion, that includes fingerprinting, as one possible choice, further makes the situation less confrontational. Thus in addition to sweetening the deal, the invention softens the deal, to make it less confrontational, and less regimented. [0064] Thus it no longer becomes a simple deal like “if you submit to being fingerprinted we will let you board 30 minutes sooner”, or the converse: “if you don't let us fingerprint you, we will make you wait 30 minutes longer and you might miss your flight”. [0065] Instead it becomes a softer deal like “let us get to know you and we'll quite likely get you on your flight sooner and reduce your chances of missing your flight”. [0066] If the automatcher 111 finds that a player is already in the garden, and in particular, if criminals are also in the garden (e.g. if the facility garden has a database of known criminals or terrorist suspects), a crime-matcher 112 checks for criminal match. [0067] If a criminal match is found, the player may be detained by way of detainer 113 such as foot brackets that quickly clamp around the player's feet to detain the player for police questioning. In the rare occurrence of such detention, the penalty is reduced. For example, the player can still continue to play while police arrive, such that the detention is not quite so boring as being hog tied or handcuffed. Additionally further reductions in penalty may be afforded by virtue of the voluntary disclosure that led to the detention. [0068] Since detentions are a rare occurrence, most of the participants are left free to wander around the pavillion and keep feeding information about themselves back to the garden. Those who are known to the garden but are free of criminal matches, are logged in by retriever 115 to their previous NSI rating, and awarder 116 provides them with extra points for their subsequent play. [0069] In no particular order, participants may wander around the pavillion and, for example, play a virtual reality game with goggles that contain a retinal or iris scanner. Those who thus volunteer for a retinal scan with scanner 120 are tested by automatcher 121 and receive points by awarder 124 for allowing the garden to get to know them, if they are previously unknown to the garden. Those who have an automatch as found by automatcher 121 are tested for criminal match by matcher 122 and detained by detainer 123 . Detainer 123 may include a head vice comprised of the virtual reality goggles, such that the goggles lock onto the player's head so that he or she cannot get them off. Thus the player is detained by way of the cord connecting the goggles to the game console. [0070] As a reduced penalty for submitting to the voluntary disclosure, the player may be allowed to continue to play a few free games while police are on their way. [0071] Assuming no criminal match in matcher 122 , a player's previous NSI is retrieved by retriever 125 , and an awarder 126 provides extra points for subsequent disclosure. Other activities in the garden may include waterplay activities, spray games, or water leisure activities such as a hot tub, jacuzzi, or the like. [0072] A participant enters to a locker room 130 to undress and submit clothing to a locker room attendant for storage. Implicit in this submission is a possibility that the locker room attendant may inspect the clothing. Preferably a video surveillance camera ensures that the locker room attendant does not steal items from the clothing. Because there may be jewellery, cash, and other valuables left with the attendant, there is preferably a security system to ensure that the attendant does no steal items from those left for safe keeping. [0073] Preferably there are dual separate tracks in locker room 130 for men and women to undress separately and each submit their personal effects to a separate locker room attendant of the same gender. [0074] Instead of a locker room attendant there may be lockers that have the possibility of scanning clothing, with a scanner 131 and the possibility of detention with detainer 132 in which a participant is detained or locked in the locker room until police arrive, should contraband be found in the clothing. [0075] However, it is expected that contraband will not be found, and that a participant will be awarded NSI points by awarder 133 for submitting to clothing inspection, and NSI points by awarder 134 for submitting to bodily inspection. [0076] Participants are free to use various spa facilities such as steam rooms, saunas, whirlpools, and the like. Participants receive a wristband and are served by an attendant who comes around and offers a free fruit platter, a free beverage, or the like, while asking questions such as “did you pack your bags yourself prior to depositing with us?” and “do you have anything to declare . . . have you been on a farm in the past 14 days . . . ”. In this way, both Customs and Immigration as well as airport security screening are combined with spa relaxation. [0077] Rather than waiting in line to answer these questions, participants simply enjoy a bath while the attendant comes around and asks questions. The attendant wears a computer system to record the answers from the participant. A waterproof wearable computer is used to capture these answers from each participant, while also identifying the participant by face recognition, biometrics, or by way of scanning the wristbands, or a combination thereof. [0078] Participants are informed of their time to board the aircraft, and the attendant ensures that participants who are in the spa do not miss their flights. Although nonparticipants (those outside the spa) could miss their flights because of delays, lineups, and background checks, the attendants ensure that those in the spa are pampered and cared for, and do not miss their flights. [0079] Thus nonterrorists can choose to enjoy a utopian airport lounge in which they obey all orders, relax, and have everything done for them. [0080] Suspicion costs everyone. When a person is suspicious, more checking is needed, and more risk is encountered. Risk costs. Thus when even a small number of people choose to opt for a suspicion reduction, there is a cost savings. The cost of the spa can be covered by this reduction in suspiciousness. [0081] Moreover, terrorism causes longer delays which result in more “air rage”. Air rage is a new epidemic where weary travellers become violent after being delayed in the long lines that are necessary in times of heightened security. However, rather than spending that time in line, where tension runs high, the time can be spent relaxing in a spa, where calming music and the thereputic baths help travellers relax. The reduction in air rage could save airports billions of dollars a year. The invention allows some of this savings to be passed to the users, by providing more calming lounge areas. [0082] [0082]FIG. 2 shows a system for allowing passengers to self organize into three classes, Antiterrorist (A) class, Business (B) class, and Coach (C) class. Incoming passengers VIP are those who have already chosen the spa experience. Passengers B.CLASS and C.CLASS lining up for business and coach class respectively, are informed of the VIP passengers and are given the option of joining the participants in the passenger line VIP. [0083] At any time they are free to enter in a line formed for VIP passengers, and then split off into a Men's Locker Room MLR, and a Women's Locker Room WLR. These passengers emerge each wearing a recyclable bathingsuit which has a barcode or other electronic code number encoded into the bathingsuit so that they can be tracked and pampered by spa facility staff. Passengers emerging from locker rooms MLR and WLR join up as A.CLASS passengers wearing their bathingsuits and ready to enjoy their waiting time soaking in a tub made of acrylic or polycarbonate optics 210 . [0084] Bath tubs and shower enclosures are often made of acrylic, or of polycarbonate. In a preferred embodiment the tub is made of smoked polycarbonate, or smoked acrylic, so that it forms optics 210 . Such a tub will have a black appearance to a user of the tub, but image sensors 203 and 204 concealed under the tub will be able to see the user of the tub. Additional image sensors 201 and 202 may also be concealed behind the dark transparent bath tub material in such a way that they provide a field of view 222 of the bather above the waterline 250 during typical usage. [0085] The intelligent bath tub has no knobs, or other adjustments, and is therefore much easier to use. The user simply strips down, and sits in the tub. and then the tub fills with water by way of activation of an actuator. [0086] Sensors 201 and 202 also monitor the amount of water in the tub, and as the tub gets close to full, the water flow is gradually reduced. A sophisticated control system is possible without much cost, since the sensors and processors and controllers are already present for security reasons. [0087] In some embodiments, a single image sensor 200 is sufficient to see into the entire tub, as well as up and out of the tub when the water is still, up to and including a critical angle of approximately 41.81 degrees (an angle of approximately 0.73). [0088] Thus the intelligent bath tub serves users of the tub by way of control of an actuator in response to user activity. [0089] The explanation of this tub has assumed that there is only one user, but the invention can also be applied to multi user baths such as whirlpools, jacuzzis, steam rooms, and other bathing environments as may be found in the airport waiting room spa of the invention. For example., a bath can begin to fill when a user sits in the tub, and then jets can massage the user's body. If another user enters the tub, other jets can be activated for that other user. A pattern of jets can operate for optimal user satisfaction, given the distribution of users in the bath. [0090] In a sauna bath, heat flow can be directed in response to the occupants of the sauna, so that the majority of users experience the best sauna bath that the bathroom environment can provide, through intelligent control of air jets, heaters, and ventilation systems. [0091] The optics 210 allows bathers to be visible from the garden, so that computer vision systems in the garden can track bathers by way of the barcodes on their bathingsuits, or other indicia. The bathingsuit barcodes can be invisible to human users, but visible only to the machines, by way of infrared or ultraviolet markings, or by way of other electronic detection means. [0092] Additionally, the computer vision systems in the facility garden can scan for suspicious activity, and scan faces of participants to ensure no suspected terrorists are present. [0093] Moreover, the computer vision systems can have other concomitant uses such as remote lifeguarding, and ensuring safety in the event of any slip-and-fall accidents, as well as keeping recordings of such incidents for insurance purposes. [0094] Preferably the bathing or spa facilities are visible to passengers in B.CLASS and C.CLASS. Thus those in the long lines for B.CLASS and C.CLASS might consider spending the time that they would be just simply standing in line, instead soaking in the spa. [0095] While bathers are relaxing in the bath, attendants can use a questioner 270 to ask questions from the users. Thus user 260 can soak in the bath and relax while answering questions like “anything to declare?”. [0096] The questioner 270 can be a videophone to a customs official, or a wearable computer attached to a spa attendant and possibly linked remotely to a Customs and Immigration office, or for recording data for being queued and reviewed by a customs official or security official. [0097] By working together, Customs, the police and security staff, the airlines, and the spa can reduce terrorism. Government and industry can work together to pamper passengers while they merely relax and obey. [0098] Passengers are helpless to produce their own tickets because they are in the bath, so as a result they are pampered and assisted in various ways. Their clothing, jewellery, and personal effects are moved forward along clothing transfer path WCT, so that these items arrive into the respective Men's Dressing Room MDR and Women's Dressing Room WDR. Thus by the time the passengers are prompted by staff to head to the MDR and WDR their clothes have been potentially examined or spot-checked and are ready. [0099] An airplane is sectioned off into three compartments, a pilot's cockpit 299 P, a class A section 299 A, and a class BC section 299 BC. A pilot P is protected by a barrier from class A passengers in section 299 A. A very strong and impermeable barrier divides class B and class C from the pilot and class A. Class A boards at the front of the plane with the pilot, because we know that class A is free of terrorists. [0100] Class B and C board behind a heavy re-enforced barrier that could contain an explosion. Preferably the barrier is behind the wings, so that in the event of an explosion in section 299 BC the aircraft would remain operational. [0101] Optionally, Class A may be split into two classes: Antiterrorist Business class AB and Antiterrorist Coach class AC. Class AB can thus board separate from class AC so that class distinction is possible within the Class A passengers. [0102] [0102]FIG. 3 shows a wristband that can be worn in an airport spa, airport lounge, or other area such as a place where NSI points can be incremented or decremented. A fastener 340 brings band 300 together. Band 300 has outside wiring 310 and inside wiring 320 . The inside wiring 320 is shown as hidden lines (dotted lines). The wiring is preferably in a lattice so that tampering with the wristband (e.g. trying to swap with someone else) would break at least some wires and de-activate the authentication loaded into core 330 . [0103] Core 330 is connected to the wiring, and when the fastener 340 joins to the other side of band 300 , core 330 can be programmed with this joining information. The joining will connect essentially random connections of the wiring, so that core 330 can be programmed with a key that is responsive to the essentially random connections. Opening the wristband will open these random connections. Re-closing the wristband (e.g. on someone else's wrist) will cause different random connections to be made, so that the key will be lost. [0104] The wristband can be re-used, but it must be re-programmed once it is disconnected and reconnected. [0105] An important aspect of the wristband is the use of sloppy connections that connect different sets of wires each time it is closed. A tolerance on the flex and differentness of the wires may also be incorporated so that a small amount of wear is acceptable but a larger difference in connectivity will be flagged as a change. [0106] Additionally, core 330 is programmed so that any disconnection will clear the key. [0107] [0107]FIG. 4 shows an examination surface for use in an examination booth. The surface is curved, preferably saddle shaped with downward pointing sides 410 and a stirrup 440 allowing a subject to be seated onto the surface. Stirrup 440 has a footprint scanner to scan the barefoot pattern of a subject and thus contribute more personal information to the garden. Additionally an interface panel 430 includes a fingerprint scanner that the user can press on, by pressing different “buttons” that are actually fingerprint scanners. Each button is labelled, allowing the user to select different tests. [0108] The surface has upward pointing front and back 400 , so that the subject can sit with legs on either side, and be examined by the contoured surface. The surface is preferably made of vitreous china or other glasslike material that is partially transparent. Sensors such as video cameras and infrared scanners behind the partially transparent surface material capture information about the subject that determine if the subject is disease carrying and also provide information about identifying aspects of the subject such as identifying scars, marks, and tattoos on the subject's body. In this way, the apparatus can also be used as a police booking station to capture information about a suspect's body. [0109] Preferably cameras or other instruments scan the subject's body in a first scanning stage to automatically determine the location of any identifying scars, marks, tattoos, or the like, and then a second scanning stage captures close-up images of these identifying features of the subject's body. [0110] The subject may volunteer to provide various samples for a free medical examination. A blood tester is included in interface panel 430 so that the subject an leave a blood sample. The surface is also curved in such a manner that it can carry away bodily wastes, so that the subject can leave behind waste matter for collection into a waste analysis bowl. The subject can defecate to surface 420 leaving a sample for medical analysis or the subjects can provide a urine sample, sperm sample, saliva sample, or the like, or other samples such as skin and hair samples for DNA analysis. [0111] Appropriate openings in the vitreous material receive samples. Sensors such as video capture devices document the collection of the samples, and provide additional data to the remote facility garden for possible later analysis by medical experts and epidemiologists. [0112] Such a disclosure booth can be used to allow persons to clear Customs and Immigration, or to clear security checkpoints quickly. For example, passengers can arrive late, e.g. perhaps only ten minutes before and international flight departs, and still board the flight through voluntary disclosure. The speed of boarding is limited only only by how fast the patient can undress himself or herself and get inspected. Because this procedure is voluntary, it allows persons to choose disclosure as a way of saving everyone, including themselves, time and effort. [0113] In all aspects of the present invention, references to “camera” mean any device or collection of devices capable of simultaneously determining a quantity of light arriving from a plurality of directions and or at a plurality of locations, or determining some other attribute of light arriving from a plurality of directions and or at a plurality of locations. [0114] References to “processor”, or “computer” shall include sequential instruction, parallel instruction, and special purpose architectures such as digital signal processing hardware, Field Programmable Gate Arrays (FPGAs), programmable logic devices, as well as analog signal processing devices. [0115] From the foregoing description, it will thus be evident that the present invention provides a design for a voluntary disclosure means, apparatus, or method of providing enhanced safety or security in proportion to the decrease in suspiciousness of the disclosee, along with means., apparatus, or method of allowing the disclosee to share in the benefits of his or her disclosure. As various changes can be made in the above embodiments and operating methods without departing from the spirit or scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings should be interpreted as illustrative and not in a limiting sense. [0116] Variations or modifications to the design and construction of this invention, within the scope of the invention, may occur to those skilled in the art upon reviewing the disclosure herein. Such variations or modifications, if within the spirit of this invention, are intended to be encompassed within the scope of any claims to patent protection issuing upon this invention. [0117] The embodiments of the invention in which I claim an exclusive property or privilege are defined as follows:	Persons such as travellers in an airport are given an opportunity to remove themselves from being under suspicion of terrorism or the like. Persons are provided with one or more opportunities to reveal information about themselves by way of a personal disclosure that would normally be unacceptably invasive if such disclosure were mandatory. The nature of the personal disclosure is such that almost all persons frequently choose to make such a disclosure in their ordinary day-to-day lives, but would be offended if required to make the same disclosure. In one embodiment, persons are given an opportunity to use an airport lounge spa facility with separate showers, saunas, steam rooms, and whirlpool baths, for men and women. Clothing is safely held (and possibly inspected) by locker room attendants while patrons are using the spa. A method of cost management is provided, whereby the reduction in suspicion (by way of the personal disclosure) of the large numbers of people using the spa is translated into a cost savings in terms of underwriting insurance, or the like, whereby this cost savings funds the construction of the voluntary personal disclosure facility. In another embodiment patrons are offered a free medical exam or health diagnostic that includes a personal disclosure, such as undressing, being scanned, or the like. Other embodiments include an opportunity to play a free Virtual Reality (VR) game using VR goggles having a retinal scanner, or an opportunity to play a free video game by pressing a fingerprint scanner to generate a virtual world from a magnified video image of the participant's thumb.	4
FIELD OF THE INVENTION This invention relates generally to the compilation of functions. More specifically, this invention relates to efficient compilation of a family of related functions. BACKGROUND OF THE INVENTION In computer programming, certain sets of functions are related. In other words, for a given set of functions, the calculation of each member function is almost identical. A common example is the set of trigonometric functions, i.e. sine, cosine, tangent, cotangent, secant, and cosecant. Each trigonometric function may be computed by first performing an argument reduction and some preliminary calculations. The argument reduction and the preliminary calculations are identical for all trigonometric functions within the set. A few unique instructions are performed at the end for each member trigonometric function. Normally, when a conventional compiler encounters a trigonometric function in a program, a separate function call is made for each. Thus, for example, even if calls to sin(theta) and cos(theta) appear in close proximity, two calls are made, each of which executes all of the common instructions, and then the few unique instructions are executed to complete the computation of the desired function. As an illustration, assume that the following statements appear in a computer program: X=sin(theta); Y=cos(theta); The conventional compiler typically makes the following calls: R 1 =call _sin(theta); R 2 =call _cos(theta); As noted above, much of the instructions to perform sine and cosine calculations are identical. For example, on the assignee's IA-64 computer architecture, each trigonometric function may take about 50 instructions to complete. Of these, about 48 instructions may be identical for sine and cosine functions (the tangent function may also have the identical 48 instructions). This indicates that only about the last two instructions are unique for the sine and cosine functions (tangent may require about 12 unique instructions). With the conventional compiler, as many as 100 instructions may be performed to calculate the sine and cosine values. However, as many as 48 instructions are performed twice, which lengthens the actual execution time and perhaps the compiled program size. Such penalty is multiplied as more member functions from a family of functions are called and the full price of executing each member function is paid by the running program. Alternatively, special functions, which return all the members (or the most commonly called members) of a related family of functions, are available. However, these function names are non-standard and the user (the programmer) must know the names of the non-standard functions to invoke it and extract values of interest from the resultant structure. While such special function calls may help to speed up the execution, programs written with such special function calls suffer from non-portability, i.e. become architecture specific, and may also become operating system specific, when more than one operating system exists for a specific architecture. SUMMARY OF THE INVENTION In one respect, an embodiment of a compiler to optimize compiling a family of related functions may include a member recognizer configured to recognize a member function from the family of related functions. The compiler may also include a family start caller configured to make a family-start function call for the family of functions related to the member function. The compiler may further include a member finish caller to make a member-finish function call for the recognized member function. Any combination of the member recognizer, family start caller, and member finish caller may be incorporated into a front end of the compiler. In another respect, an embodiment of a method to optimize compiling a family of related functions may include recognizing a member function from said family of related functions. The method may also include making a family-start call for the family of related functions and making a member-finish call for the recognized member function. Further, the method may include optimizing resulting function calls. The above disclosed embodiments may be capable achieving certain aspects. For example, no special action may be required from the programmer. Also, the portability of the original source code (or program) may be maintained. In addition, the source of identification for the family of related functions may be easily modified. Further, the resulting program may execute faster. Still further, standard compiler optimization techniques may be used to achieve these efficiency improvements. BRIEF DESCRIPTION OF THE DRAWINGS Features of the present invention will become apparent to those skilled in the art from the following description with reference to the drawings, in which: FIG. 1 illustrates a flow chart of an exemplary method for optimizing a set of function calls within a family of related functions. DETAILED DESCRIPTION For simplicity and illustrative purposes, the principles of the present invention are described by referring mainly to exemplary embodiments thereof. However, one of ordinary skill in the art would readily recognize that the same principles are equally applicable to many situations where a family of related function calls may be optimized. As described in the Background section, a family of related functions is typified in that some part of the instructions performed are identical for each member function of the family. While not exhaustive, families of related functions include trigonometric functions (sin, cos, tan, etc), hyperbolic functions (sin h, cos h, tan h, etc), square root (sqrt, reciprocal sqrt), and the like. For example, when calculating trigonometric functions, each member function (sin, cos, tan) may be computed by first performing an argument reduction and some preliminary calculations. These computations are typically identical for all member functions. Then computation for each member function may be completed by performing a few unique instructions at the end. Thus, if the compiler recognizes sin( ), cos( ), and tan( ) as belonging to a family of trigonometric functions, then significant savings in execution time may be realized by eliminating execution of duplicate instructions. Using the IA-64 computer architecture given above as an example (see the Background section), it is seen that 48 instructions may be eliminated when computing both sin(theta) and cos(theta). Thus instead of executing 100 instructions, only 52 instructions may need to be executed. If tan(theta) is also needed, the savings becomes that much greater (64 instructions versus 160—tangent may require more unique instructions). FIG. 1 illustrates a flow chart of an exemplary method for optimizing a set of function calls within a family of related functions. As shown, the method starts at step 110 . At step 120 , a function call is parsed. At step 130 , it is determined whether the function is a member of a known family of related functions. If the function is not a member of a known family of related functions, then the method proceeds to step 160 . If the function is a member of a known family, then the method proceeds to step 140 where a family-start function call is made. After the family-start call is made, this is followed in step 150 by a member-finish function call. Afterwards, in step 160 , whether or not the end of the program has been reached is determined. If not, then the method iterates from step 120 to parse more function calls. If the end of the program has been reached, then the method proceeds to step 170 where the resulting function calls are optimized. As an illustration, again assume that the following statements appear in a computer program: X=sin(theta); Y=cos(theta); According to the exemplary method, in step 130 , the statement X=sin(theta) would be recognized as being a member of a known family of related functions, namely the trigonometric family of functions. Thus after performing steps 140 and 150 , the result may look like the following: R 1 =call _trig start(theta); R 2 =call _sin finish(R 1 ); The program statement Y=cos(theta) would be treated in a similar manner and the result may look like the following: R 3 =call _trig start(theta); R 4 =call _cos finish(R 3 ); Thus prior to entering step 170 for optimization, the program statements may be translated as follows: R 1 =call _trig start(theta); R 2 =call _sin finish(R 1 ); R 3 =call _trig start(theta); R 4 =call _cos finish(R 3 ); It is seen that the exemplary method entails steps of recognizing member functions, and simply replacing them with appropriate family-start and member-finish function calls. The end result of this process may seem to result in a code that appears to be inefficient at a first glance. Looking at the example given above, the result is that _trig start( ) is called twice with the same argument theta. This occurs because the exemplary method calls for replacing the program statement cos(theta) with the family-start function _trig start( ), followed by the unique member-finish function _cos finish( ), even though the same family-start function was called previously due to the presence of the program statement sin(theta). However, after this replacement process is completed, all instructions, including the family-start calls, may be treated as ordinary instructions during the optimization step 170 . Thus, the family-start functions may be subject to all optimization techniques. These techniques may include common subexpression elimination, code motion, and dead-code elimination. In this instance, during optimization performed at step 170 , a standard common elimination routine, which is employed by most standard optimizing compilers, would recognize that R 1 and R 3 are identical because they both result from calling _trig start( ) with the same argument. The elimination routine would typically automatically transform the above code and the result may look like the following: R 1 =call _trig start(theta); R 2 =call _sin finish(R 1 ); R 4 =call _cos finish(R 1 ) When optimization is completed, the total number of instructions is reduced since the second call to _trig start( ), taking up to 48 instructions to complete for the IA-64 architecture, has been eliminated. The method may be relatively simple to implement in compilers. Mainly, a compiler may include a member recognizer configured to recognize a member function from a family of related functions. The compiler may also include a family start caller configured to make a family-start function call for the family of related functions and a member finish caller to make a member-finish function call for said member function. In this manner, the original function call is replaced the appropriate family start and member finish calls to compute the desired value. Afterwards, the standard optimizer may be used to optimize the program. Any combination of the member recognizer, family start caller, and the member finish caller may be incorporated into a front end of the compiler. Also, any of them may be incorporated into other phases of the compiling. For example, the transformation of the original function calls to the family start and member finish calls may be performed during a prepass phase of the compilation. Note that the family-start and member-finish calls may be made to appear as primitive instructions in an intermediate language, i.e. a language independent of specific architectures and independent of specific operating systems. Because these calls have been made to appear as primitive instructions, the optimizer may also perform optimization on the calls made in the same intermediate language. The intermediate language code, whether optimized at the intermediate language level or not, may undergo an architecture specific optimization. For example, the compiler may in-line expand one or both the family-start and member-finish functions to take advantage of hardware parallelism that a particular architecture provides. The code may also undergo an operating system specific optimization. In these instances, certain operating system calls may allow access to the hardware resources faster than other operating system calls. In one implementation, the call to the family-start function may return a structure of values. For example, in an implementation of the trigonometric family of functions, the angular argument theta may be broken into two angles A and B, wherein sin(A) and cos(A) are obtained quickly from a look-up table and sin(B) and cos(B) are quickly computed by a short polynomial. The final result may be then computed from well-known trigonometry identities: sin(theta)=sin( A+B )=sin( A )cos( B )+cos( A )sin( B ); cos(theta)=cos( A+B )=cos( A )cos( B )−sin( A )sin( B ); Then, it may be convenient to have _trig start ( ) return four values, corresponding to sin(A), cos(A), sin(B), and cos(B), as shown by the following declaration in the C programming language: typedef struct { double sina; double cosa; double sinb; double cosb; } trigreturn; Then the functions _sin finish( ) and _cos finish( ) can be described in the C programming language as follows: _sinfinish(trigreturn x) { double temp; temp = x.sina * x.cosb; return fma(x.cosb, x.sina, temp); } and _cosfinish(trigreturn x) { double temp; temp = x.cosa * x.cosb return fma(-x.sina, x.sinb, temp); } For informational purposes, fma( ) is an function introduced into the C99 standard for the C language. Thus using the fma( ) function does not destroy portability. A call to fma(a, b, c) computes ab+c with only one rounding, after the sum has been computed. On architectures such as IA-64, Power PC™, and PA-RISC™, fma( ) is available as a single machine-language instruction. Also, many architectures such as IA-64, Power PC™, and PA-RISC™ contain variants of fma( ) to compute ab−c (often called fms( )) and −ab+c (often called fnma( )). With these architectures, the compiler can replace an fma( ) call with one of its arguments negated with one of the alternate instructions, which avoids an extra operation to actually negate that argument. When compiling for architectures lacking the fma( ) instruction, the finish routines may be rewritten in terms of simple addition and multiplication, with a slight loss of accuracy, but retaining relatively high performance. Examples of such architectures are IA-32™ and Sparc™. In another implementation of the trigonometric functions, the completely evaluated approximating polynomials for sin(B) and cos(B) are not returned. Instead, the value B itself is returned, as well as approximations to sin(B)/B, and (cos(B)−1)/B. While these quantities may appear to be complicated, the sin(B)/B results from omitting the final multiplication of an approximating polynomial to sin(B) by B. Likewise, (cos(B)−1)/B results from omitting the final constant term 1 from the cosine approximation, as well as omitting a multiplication by B. This seemingly more complicated approach leads to slightly better accuracy, at no cost in additional computation. The _trig start( ) routines may be shorter, and the member-finish function routines may be slightly longer. For this implementation, the defining structure may look like the following: typedef struct { double b; double sina; double cosa; double sseriesb; double cseriesb; } trigreturn2; The finishing member functions may become one instruction longer each as shown below: _sinfinish(trigreturn2 x) { double temps; temps = x.sina x.cseriesb; temps = fma(x.sseriesb, x.cosa, temps); return fma(temps, x.b, x.sina); } and _cosfinish(trigreturn2 x) { double tempc; tempc = x.cosa * x.cseriesb; tempc = fma(-x.sina, x.sseriesb, tempc); return fma(tempc, x.b, x.cosa); } In yet another implementation of the trigonometric functions, the call to the family-start function returns a structure with resultant values of all member functions. In this instance, the defining structure may look like the following: typedef struct { double sinresult; double cosresult; } trigreturn3; For this implementation, the _sin finish(x) and cos finish(x) may simply refer to the x. sin result and x. cos result quantities, respectively. However, this is not preferred since it occasionally sets spurious exception bits. Also, it may be that not all member functions are called in the source code resulting in unnecessary calculations being performed. Hyperbolic functions lend themselves to a substantially similar treatment to the trigonometric functions. The details of the implementation should be obvious to one of ordinary skill. Square root and reciprocal square root also lend themselves to this exemplary methodology. Often, to calculate the square root, the reciprocal square root is calculated first, and then the square root is derived from the reciprocal square root. Using the exemplary methodology outlined, the family-start function, perhaps named _rsqrt( ) may return the reciprocal square root itself. In this instance, because only a single value is returned, a structure associated with the result may not be necessary. The finishing routine, perhaps named _sqrt finish( ), using the result named recip from _rsqrt(x), may look like the following: double _sqrtfinish(double x, double recip) { double root, d; root = x * recip; //stopping here may leave rounding error d = fma (root, root, -x); return fma (d, 0.5 * recip, root); // correctly rounded } Thus when the compiler encounters a sqrt(x), the compiler may simply insert recip=_rsqrt(x) followed by a call to _sqrt finish(x, recip). However, if the compiler encounters sqrt(x) as a denominator of an expression, for example 1/sqrt(x), it may simply insert recip=_rsqrt(x) and use the value recip as the result of 1/sqrt(x), and the finishing routine can be empty. This technique for square roots is of particular importance in graphic rendering where the reciprocal square root is used more frequently than the square root itself. Again, it bears repeating that the invention is not limited to trigonometric, hyperbolic, and square root functions. The scope of the invention includes any family of related functions. Note that the knowledge of these families of related functions need not be encoded in the compiler itself. It may be preferred that the definitions for function families are contained in a separate look-up table or other data store. For example, data store may include ascii files, binary data files, database files, and more. The benefit of this implementation is that defining new families does not require changes to the actual compiler executable; the compiler may continue to work in the same manner regardless of the information in the data store. Another benefit from such an implementation is that it may be possible to add custom families to the data store and receive the same efficiency improvements from custom defined families as from common sets of functions like the trigonometric or hyperbolic functions discussed above. Also, it is seen that no special knowledge is required on the part of the programmer. The programmer writes code in a standard language (C, C++, J++, Fortran, etc). Thus, portability of the source code is maintained. While the invention has been described with reference to the exemplary embodiments thereof, those skilled in the art will be able to make various modifications to the described embodiments of the invention without departing from the true spirit and scope of the invention. The terms and descriptions used herein are set forth by way of illustration only and are not meant as limitations. In particular, although the method of the present invention has been described by examples, the steps of the method may be performed in a different order than illustrated or simultaneously. Those skilled in the art will recognize that these and other variations are possible within the spirit and scope of the invention as defined in the following claims and their equivalents.	Consider a set of functions, each of whose calculations are almost identical. A common example is the set of trigonometric functions sine, cosine, and tangent. Each of these functions is computed by first performing argument reduction and some preliminary calculations, which are identical for all members of the set. A few unique instructions are performed at the end for each of the functions in the set. Normally, when such functions are encountered, a separate sequence of instructions is called for each function even if the functions appear in close proximity. This results in duplicate instructions being performed which increases execution time and length of compiled program. Specialized functions exists to minimize execution, but programs with such specialized function calls suffer from non-portability. The present invention includes a method and a system to optimize function calls for faster execution while maintaining portability. The present invention requires no specialized knowledge on the part of the programmer and also utilizes standard compiler optimization techniques.	6
BACKGROUND OF THE INVENTION This invention relates, in general, to a waste pickup device, and, in particular, to a waste pickup device that has a bag into which the waste can be placed. DESCRIPTION OF THE PRIOR ART In the prior art various types of pickup devices have been proposed. For example, U.S. Pat. No. 5,382,063 to Wesener et al discloses a waste collector having a container with a handle and a pivoted lid to contain the waste. U.S. Pat. No. 4,896,912 to Parnell discloses a waste collector in which a plastic bag is tied around the entire collector. U.S. Pat. No. 6,439,627 to Devane discloses a waste collector in which a plastic bag is placed within a container and is secured with tape and a relief notch in the back of the container. U.S. Pat. No. 5,564,762 to Ring discloses a waste collector having a container with an open end a bag which completely surrounds the container and a pusher member for pushing waste into the collector. SUMMARY OF THE INVENTION The present invention is directed to a pickup device that has a scoop for picking up waste and the device has a plastic bag lining the device which can be used to dispose of the waste. It is an object of the present invention to provide a new and improved pickup device for collecting and disposing of waste. It is an object of the present invention to provide a new and improved pickup device which incorporates a plastic bag to handle the waste. It is an object of the present invention to provide a new and improved pickup device which is easy to use and inexpensive to manufacture. These and other objects and advantages of the present invention will be fully apparent from the following description, when taken in connection with the annexed drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of the present invention. FIG. 2 is a bottom view of the present invention. FIG. 3 is a side view of the present invention and a plastic bag about to be inserted into the present invention. FIG. 4 is a side view of the present invention and a plastic bag inserted into the present invention. FIG. 5 is a side view of the present invention and a plastic bag inserted into the present invention and a partial view of a user's hand holding the invention and the bag. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings in greater detail, FIG. 1 shows a side view of the present invention 1 . The scoop 1 is essentially funnel shaped and has a top surface 2 , an open front 3 , a handle 4 at the back of the scoop, and an aperture 5 in the bottom of the scoop. The aperture 5 can be more clearly seen in FIG. 2 . The aperture 5 communicates with the open front end 3 of the scoop 1 , and allows an ordinary plastic grocery bag 6 (shown in FIGS. 3-5 ) to be inserted into the front end of the scoop and out through the aperture 5 in the bottom of the scoop. FIG. 3 shows an ordinary plastic grocery bag 6 about to be inserted through the open front end 3 of the scoop. The plastic bag has a rear end 8 which is inserted first through the front end of the scoop. The handles 7 of the bag are located at the front ends of the bag and are furthest away from the open end 3 of the scoop. As seen in FIG. 4 , once the bottom 8 of the bag 6 is inserted into the scoop, it is drawn through the aperture 5 until the bottom 8 protrudes from the bottom of the scoop. With the bottom 8 protruding from the aperture 5 , the handles 7 and a good portion of the front of the bag 6 still protrudes from the front of the scoop. Once the bag 6 and the scoop 1 are in the relative position shown in FIG. 4 , the handles 7 and the remaining front end of the bag 6 can be passed over the outside surface of the scoop 1 . A user can then grasp the handles 7 with the thumb and fore finger of one hand 9 and hold them against the handle 4 . This allows the leading edge of the opening 3 of the scoop to be covered by the bag 6 . When a user scoops waste with the leading edge of the scoop, the bag 6 will prevent the scoop from being soiled. The interior surfaces of the scoop will not be soiled since they are also covered by the bag. In fact, the interior surfaces of the bag 6 are the only surfaces that will contact the waste and be soiled by the waste. This eliminates the need to clean the scoop and discourages unsanitary conditions. In order to use the present invention 1 , a conventional plastic bag 1 is inserted into the open end 3 of the scoop with the bottom 8 of the bag being closest to the scoop and the handles 7 and the open end of the bag being remote from the open end 3 . The bottom 8 of the bag is passed through the scoop and brought out through the aperture 5 in the bottom of the scoop, as shown in FIGS. 4 and 5 . The user would then fold the bag over the outside of the scoop until the handles 7 are adjacent the handle 4 of the scoop. The user would then pinch the handles 7 against the handle 4 of the scoop using his/her thumb and fore finger. The user would then be ready to scoop up waste by using the front edge of the scoop. As the waste is brought into the scoop, the user could tilt the scoop so the waste would fall into the portion of the bag 6 that protrudes from the aperture 5 and the bottom of the scoop 1 . With the waste in the protruding portion of the bag, it cannot fall out accidentally, and the user can scoop additional waste without the danger of the waste, already scooped, falling out. Once scooping is complete, the user releases the handles 7 of the bag 6 , and the filled bag falls out through the bottom opening 5 and into a container for disposal. During the entire scooping process the waste will only make contact with the interior portion of the bag 6 . It should be noted that the present invention has been described as using a conventional plastic grocery bag, however, it should be understood that any container that can serve the intended purpose can be used without departing from the scope of the invention. Although the Poop Scoop & Bagger and the method of using the same according to the present invention has been described in the foregoing specification with considerable details, it is to be understood that modifications may be made to the invention which do not exceed the scope of the appended claims and modified forms of the present invention done by others skilled in the art to which the invention pertains will be considered infringements of this invention when those modified forms fall within the claimed scope of this invention.	A pickup device that has a scoop for picking up waste and the device has a plastic bag lining the device which can be used to dispose of the waste.	4
CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of U.S. Provisional Patent Application No. 60/674,075 filed Apr. 22, 2005. BACKGROUND OF THE INVENTION [0002] This invention relates to medical procedures carried out without the formation of an incision in a skin surface of the patient. [0003] Such procedures are described in U.S. Pat. Nos. 5,297,536 and 5,458,131. [0004] As described in those patents, a method for use in intra-abdominal surgery comprises the steps of (a) inserting an incising instrument with an elongate shaft through a natural body opening into a natural body cavity of a patient, (b) manipulating the incising instrument from outside the patient to form a perforation in an internal wall of the natural internal body cavity, and (c) inserting a distal end of an elongate surgical instrument through the natural body opening, the natural body cavity and the perforation into an abdominal cavity of the patient upon formation of the perforation. Further steps of the method include (d) inserting a distal end of an endoscope into the abdominal cavity, (e) operating the surgical instrument to perform a surgical operation on an organ in the abdominal cavity, (f) viewing the surgical operation via the endoscope, (g) withdrawing the surgical instrument and the endoscope from the abdominal cavity upon completion of the surgical operation, and (h) closing the perforation. [0005] Visual feedback may be obtained as to position of a distal end of the incising instrument prior to the manipulating thereof to form the perforation. That visual feedback may be obtained via the endoscope or, alternatively, via radiographic or X-ray equipment. [0006] The abdominal cavity may be insufflated prior to the insertion of the distal end of the endoscope into the abdominal cavity. Insufflation may be implemented via a Veress needle inserted through the abdominal wall or through another perforation in the internal wall of the natural body cavity. That other perforation is formed by the Veress needle itself. U.S. Pat. No. 5,209,721 discloses a Veress needle that utilizes ultrasound to detect the presence of an organ along an inner surface of the abdominal wall. [0007] A method in accordance with the disclosures of U.S. Pat. Nos. 5,297,536 and 5,458,131 comprises the steps of (i) inserting an endoscope through a natural body opening into a natural body cavity of a patient, (ii) inserting an endoscopic type incising instrument through the natural body opening into the natural body cavity, (iii) manipulating the incising instrument from outside the patient to form a perforation in an internal wall of the natural internal body cavity, (iv) moving a distal end of the endoscope through the perforation, (v) using the endoscope to visually inspect internal body tissues in an abdominal cavity of the patient, (vi) inserting a distal end of an elongate surgical instrument into the abdominal cavity of the patient, (vii) executing a surgical operation on the internal body tissues by manipulating the surgical instrument from outside the patient, (viii) upon completion of the surgical operation, withdrawing the surgical instrument and the endoscope from the abdominal cavity, (ix) closing the perforation, and (x) withdrawing the endoscope from the natural body cavity. [0008] The surgical procedures of U.S. Pat. Nos. 5,297,536 and 5,458,131 reduce trauma to the individual even more than laparoscopic procedures. Hospital convalescence stays are even shorter. There are some potential problems with the procedures, such as trauma to the hollow internal organs through which the endoscopic instruments are passed to the target surgical site, generally but not exclusively within the abdominal cavity. [0009] The procedures of U.S. Pat. Nos. 5,297,536 and 5,458,131 may be termed trans-organ procedures insofar as surgical operations are conducted via organs that are otherwise not implicated in the procedures. OBJECTS OF THE INVENTION [0010] It is an object of the present invention to provide improvements on the afore-described surgical procedures. [0011] It is another object of the present invention to provide a method and/or an associated device for protecting a passageway in an internal hollow organ during a trans-organ procedure. [0012] These and other objects of the present invention will be apparent from the drawings and detailed descriptions herein. While every object of the invention is believed to be attained in at least one embodiment of the invention, there is not necessarily any single embodiment that achieves all of the objects of the invention. SUMMARY OF THE INVENTION [0013] A medical method comprises, in accordance with the present invention, providing a tubular member, inserting the tubular member through a patient's mouth into the patient's esophagus so that at least a portion of the tubular member is disposed in the patient's esophagus as a liner, and subsequently inserting flexible endoscopic surgical or diagnostic instruments through the patient's mouth and the tubular member in the esophagus into the patient's stomach. The tubular member is removed from the patient's esophagus after termination of the procedure. [0014] Pursuant to another feature of the present invention, the inserting of the tubular member into the patient's esophagus includes providing a flexible deployment tube containing the tubular member in a collapsed configuration, inserting at least a distal end portion of the deployment tube through the patient's mouth into the patient's esophagus, ejecting the tubular member from a distal end of the deployment tube, and subsequently expanding the tubular member from the collapsed configuration to an expanded configuration inside the patient's esophagus. [0015] The tubular member may include a frame made of a shape-memory material; the expanding of the tubular member then occurs automatically upon ejecting of the tubular member from the deployment tube. [0016] Typically, the method further comprises removing the deployment tube from the patient's esophagus after the ejecting of the tubular member and prior to the inserting of the endoscopic instruments. [0017] In a trans-organ surgical procedure, distal end portions of the surgical instruments are moved through at least one incision or perforation formed in a digestive tract of the patient. [0018] A surgical kit in accordance with the present invention comprises at least one surgical instrument having an elongate flexible shaft having a length longer than a human adult esophagus, and a tubular member insertable through a patient's mouth so as to be disposed at least partially as a liner in the patient's esophagus. The tubular member has an expanded configuration and an at least partially collapsed insertion configuration, the expanded configuration having an inner diameter larger than an outer diameter of the flexible shaft so as to enable passage of a distal end portion of the shaft through the tubular member in the expanded configuration. [0019] Pursuant to another feature of the present invention, the surgical kit further comprises a flexible deployment tube containing the tubular member in the collapsed configuration. At least a distal end portion of the deployment tube is insertable through the patient's mouth into the patient's esophagus. An ejector is disposable at least partially inside the deployment tube for ejecting the tubular member from a distal end of the deployment tube. The tubular member is expandable from the collapsed configuration to the expanded configuration inside the patient's esophagus. [0020] The tubular member may include a frame made of a shape-memory material, so that the tubular member expands automatically upon ejection from the deployment tube. [0021] A surgical tool may be provided having an elongate flexible shaft with an operative tip for forming at least one incision or perforation in a digestive tract of the patient. This tool is used after deployment of the esophageal liner. [0022] An esophageal liner in accordance with the present invention comprises a tubular member having an expandable frame covered with a protective web material. The web material may include wire mesh and/or a film material. BRIEF DESCRIPTION OF THE DRAWINGS [0023] FIG. 1 is a schematic perspective view of an esophageal liner in accordance with the present invention. [0024] FIG. 2 is a partial cross-sectional view of the esophageal liner of FIG. 1 . [0025] FIG. 3 is a schematic cross-sectional view of a person's upper digestive tract. [0026] FIG. 4 is a schematic cross-sectional view similar to FIG. 3 , showing endoscopic instruments inserted in a trans-organ procedure pursuant to the teachings of U.S. Pat. Nos. 5,297,536 and 5,458,131. [0027] FIGS. 5A-5D are schematic cross-sectional views of a person's upper digestive tract, showing successive steps in an endoscopic procedure utilizing the esophageal liner of FIG. 1 , in accordance with the present invention. [0028] FIGS. 6A and 6B are schematic perspective views of an endoscope provided with an inflatable sheath for protecting the esophagus during an endoscopic procedure, respectively showing the sheath in a deflated and an expanded configuration. [0029] FIG. 7 is a schematic perspective view of the endoscope and the expanded sheath of FIG. 6B , showing the endoscope and sheath disposed in or traversing a person's esophagus. [0030] FIGS. 8A-8C are schematic perspective views showing successive steps in the utilization of an esophageal liner in the form of an inflatable balloon, pursuant to the present invention. DETAILED DESCRIPTION [0031] As illustrated in FIGS. 1 and 2 , an esophageal liner 10 comprises a tubular member having an expandable frame 12 covered with a protective web material 14 . The web material 14 may include wire mesh 16 and/or a film or fabric material 18 . The web material may be disposed along an inner side as well as an outer side of frame 12 . [0032] Frame 12 is made at least in part of a shape-memory material such as Nitinol that is deformable to a collapsed configuration so that liner 10 may be disposed in a collapsed configuration 20 inside a flexible deployment tube 22 ( FIG. 5A ). [0033] In a trans-organ procedure as described in U.S. Pat. Nos. 5,297,536 and 5,458,131, flexible endoscopic instruments 24 are inserted through a patient's mouth MT, past the soft tissues 26 and possible varices 28 of a patient's esophagus ES and into the patient's stomach ST ( FIG. 3 ). As illustrated in FIG. 4 , the stomach wall 30 is incised to form a perforation 32 , which is provided with a port element 34 . Distal end portions of the instruments 24 are then passed through the port element 34 and consequently the perforation 32 into the abdominal cavity AC. [0034] Instruments 24 can damage the soft tissues 26 and varices 28 of the esophagus ES during this procedure. However, this damage can be obviated or reduced through the use of the liner 10 of FIG. 1 . At the onset of a trans-organ procedure through a patient's upper GI tract, as described in U.S. Pat. Nos. 5,297,536 and 5,458,131, deployment tube 22 is inserted into a patient's esophagus ES ( FIG. 5A ). Liner 10 is then ejected from tube 22 into the esophagus ES by a forward or distally directed movement of a plunger or pusher member 23 and permitted to expand from the collapsed configuration 20 to the expanded use configuration. Owing to the shape-memory material (e.g., Nitinol), the tubular frame 12 automatically expands upon ejecting of the collapsed liner 20 from deployment tube 22 . In the expanded configuration ( FIG. 5B ), liner 10 protects the esophagus ES from being damaged by endoscopic instruments 24 inserted through the esophagus and stomach ST during a trans-organ procedure wherein distal end portions of the instruments 24 are passed through an incision or perforation 32 formed in the stomach wall 30 . [0035] Deployment tube 22 is removed from esophagus after the ejection of liner 10 and prior to the insertion of instruments 24 . At the end of the procedure, perforation 32 is closed as indicated at 38 in FIGS. 5C and 5D . The liner 10 is removed from the patient's esophagus ES. As illustrated in FIG. 5C , a grasper 36 may be used to pull the liner 10 from the esophagus ES through the mouth MT. [0036] As depicted in FIGS. 6A, 6B and 7 , an upper GI endoscope 40 with a hand piece 42 having directional control knobs 44 has a flexible insertion member 46 to which a sheath 48 is removably attachable. Sheath 48 particularly takes the form of an elongate annular balloon with a deflated configuration shown in FIG. 6A and an expanded configuration shown in FIGS. 6B and 7 . After attachment of sheath 48 to insertion member 46 , the insertion member and the sheath, in a deflated configuration, are inserted into the esophagus ES of a patient. Upon a sufficient degree of insertion, a pressure source such as a liquid-filled syringe 50 is operated to pressurize and inflate the balloon 48 to an expanded configuration ( FIGS. 6B and 7 ). An incising instrument (not shown) may be inserted through a biopsy or working channel of endoscope 40 and manipulated from outside the patient to form an opening 52 in a wall 54 of the patient's stomach ST. Thereupon, the distal end portion (not separately enumerated) of endoscope insertion member 46 is passed through opening 52 to view organs in the patient's abdominal cavity (not illustrated). It may be necessary in some cases to deflate balloon sheath 48 to permit a repositioning of endoscope insertion member 46 . After completion of a trans-gastric procedure, opening 52 is closed (see FIGS. 5C, 5D ) and balloon sheath 48 is deflated and withdrawn from the esophagus ES, together with endoscope insertion member 46 . [0037] As depicted in FIG. 8A , an esophageal liner may take the form of a balloon 56 initially disposed in a collapsed configuration inside a distal end portion of a flexible deployment tube 58 . Upon insertion of the distal end portion of the deployment tube 58 into an esophagus ES, a plunger or push rod 60 is moved in the distal direction to eject the deflated balloon 56 from the deployment tube and into the esophagus ES. Then deployment tube 58 is withdrawn from the patient and a pressure source such as a liquid-filled syringe 62 is actuated to inflate the balloon 56 into an expanded annular configuration shown in FIG. 8B . An insertion member 64 of an endoscope 66 is then passed through a lumen 68 of the inflated balloon liner member 58 , as shown in FIG. 8C . Lumen 68 may be coated with a lubricant to facilitate sliding of the endoscope insertion member 64 in alternate directions along the esophagus ES [0038] Various instruments and devices disclosed herein may be packaged as surgical kits that facilitate the delivery, organization and use of the instruments and devices. Such kits may comprise at least one surgical instrument 24 ( FIG. 4 ) having an elongate flexible shaft with a length longer than a human adult esophagus ES, as sell as esophageal liner 10 or 56 or sheath 48 . Liner 10 or 58 or sheath 48 has an expanded configuration and an at least partially collapsed insertion configuration, the expanded configuration having an inner diameter sufficiently large as to enable passage of a distal end portion of the shaft through the liner or sheath in the expanded configuration thereof. The surgical kits may further comprise flexible deployment tube 22 or 58 , including ejector rod 23 or 60 , respectively. A surgical tool such as a scalpel may be provided having an elongate flexible shaft with an operative tip in the form of a cutting blade or incising element for forming at least one incision or perforation in a digestive tract of the patient. This tool is used after deployment of the esophageal liner. [0039] Although the invention has been described in terms of particular embodiments and applications, one of ordinary skill in the art, in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding the scope of the claimed invention. Accordingly, it is to be understood that the drawings and descriptions herein are profferred by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof.	A medical method utilizes a tubular member. The method comprises inserting the tubular member through a patient's mouth into the patient's esophagus so that at least a portion of the tubular member is disposed in the patient's esophagus as a liner, and subsequently inserting flexible endoscopic surgical or diagnostic instruments through the patient's mouth and the tubular member in the esophagus into the patient's stomach. The tubular member is removed from the patient's esophagus after termination of the procedure.	0
FIELD OF THE INVENTION The present invention relates to a device for controlling the electrical activity of the heart. More particularly, the invention relates to a device and a method for the cessation and/or prevention of malignant cardiac arrhythmias. BACKGROUND OF THE INVENTION Sudden cardiac death is heralded by the abrupt loss of consciousness within a short period of time (usually not more than one hour) after the onset of acute symptoms. Estimates indicate nearly 400,000 sudden cardiac deaths annually for the USA only. Malignant cardiac arrhythmias such as Ventricular Tachycardia (VT) and Ventricular Fibrillation/Flutter (VF) are included in one category that is a major cause of sudden death usually associated with a diseased human heart. When VT/VF occurs, the patient may die within a few minutes without immediate intensive care. The conventional treatment which is normally given to the patient in the hospital is delivering a high energy electrical shock to the heart, usually from 200-400 Joules (J). The shock is applied between two electrodes (paddles) of an external defibrillator attached to the patient's chest. This shock resets the electrical activity of the heart, so as to enable a new natural initiation of normal electrical activity. However, these relatively high energy levels may cause heart tissue damage, especially in cases of multiple shocks, and in the long run may be dangerous, particularly in patients with a diseased heart. In addition, due to the severe pain caused by high energy impulses plus possible harm by severe contraction of the body musculature, high energy cardiac shocks are usually administered to unconscious or anesthetized patients. The most effective method for appropriate management of patients who suffer from VT/VF is by employing an implantable cardiovertor defibrillator (ICD) device. This ICD applies electrical shocks directly to the heart when the device itself diagnoses VT/VF. These directly applied shocks are of much lower energy than those of the external defibrillator (normally ranging between 10 and 30 J), but, even this relatively low-energy application is very painful and may be harmful to the heart muscle in the long run. Normal heart activity is controlled by impulses, which are generated at the sino-atrial node, and propagate from cell to cell through the special conduction system and myocardium, thereby causing an ordered contraction. Excitation in normal heart tissue is followed and terminated by refractoriness. This important feature of the heart provides it with electrical stability, so that abnormal excitation waves cannot propagate during the refractory period. The exact mechanisms of malignant cardiac arrhythmias are not completely clear. In most cases it is assumed that they result from a “source” in the heart, around which a closed electrical circuit is generated, thereby forming a “reentry” path in the myocardium. There are two main approaches for management of malignant cardiac arrhythmia: pharmacological and non-pharmacological. The former generally can prevent and treat malignant cardiac arrhythmias, however its clinical effect for preventing sudden cardiac death is relatively low. In the non-pharmacological approach, malignant arrhythmias such as VT or VF may be treated by electrical shock (defibrillation/cardioversion) and can be prevented by ablation (annihilation) of part of the re-entry pathway or of the “source” of abnormal electrical activity. All the methods described above have not yet provided complete satisfactory solutions to the appropriate overall management of malignant cardiac arrhythmias. It is an object of the present invention to provide a method and a device for the management of malignant cardiac arrhythmia, which overcomes the drawbacks of the prior art. It is another object of the present invention to provide a method and a device for the management of malignant arrhythmia, using very low energy impulses. It is still another object of the present invention to provide a method and a device for the management of malignant arrhythmia without immediate or delayed negative effects on the patient's myocardium. It is still another object of the present invention to provide a method and a device for the management of VT/VF, the use of which is not painful. Other objects and advantages of the invention will become apparent as the description proceeds. SUMMARY OF THE INVENTION While the device of the invention is designated herein as a “device for the cancellation of unwanted excitation waves”, it should be understood that the “unwanted excitation waves” are those causing cardiac tachyarrhythmias, and the use of the device to prevent or terminate these waves or other related pathological phenomena is included in the invention. The device of this invention comprises the means for canceling unwanted excitation waves that propagate in an excitable tissue, by generating an excitation wave that spreads preferentially in a desirable direction. The excitation wave, also termed Device-Generated Excitation Wave (DGEW) may be directed opposite to that of the unwanted excitation wave and could cancel it or reduce it to such a magnitude that it ceases to propagate and decays. Said means for controlling the spread of the DGEW comprises two bipolar stimulating electrodes, which are adapted to be inserted into the excitable tissue at two different locations. Each stimulation electrode is fed by a power supply. Each stimulation electrode preferably comprises a pair of conducting needles, each of which comprises a relatively sharp tip at its distal end, and the proximal end of each such needle is connected to the contact of said power supply. When in use, each needle of the pair has an opposite polarity and they form a closed conducting current path through the underlying excitable tissue. The proximal end of each opposite-polarity needle is connected to a different contact of the corresponding power supply. When reference is made herein to a first and a second power supply, one for each pair of opposite-polarity stimulation electrodes, this should be understood to signify that the means for independently feeding power to each needle pair is provided, whether through two separate power sources or through a single power source with two separately controllable outputs. The device further comprises a first and second control circuitry, respectively, for generating the required amplitude and duration of the voltage applied between the respective needles. This forces a clamped current impulse to flow between the needles of each stimulation electrode. While reference is made to a first and second control circuitry, they can and generally are included in a single electronic circuit. The first power supply, which drives the first stimulation electrode, is set to generate a first current stimulus, S 1 , with magnitude that is lower than the threshold level of the excitable tissue. Hereinafter, the term “threshold lever” is used to describe the current stimulus magnitude, at which the tissue becomes excited and the DGEW starts to propagate actively throughout the tissue. Stimuli below the threshold level cannot elicit an actively propagating wave along the tissue and decays over space and time. The second power supply, which drives the second stimulation electrode, is set to generate a second current stimulus, S 2 , with magnitude that is higher than the threshold level of the excitable tissue. The terms “first and second” current stimuli do not indicate timing, but indicate that the stimuli are delivered by the first and the second stimulating electrode, respectively. The combination of S 1 and S 2 generates a DGEW, which spreads preferentially in one direction, that is controllable and can be made to be opposing to the unwanted wave. The delay between S 1 and S 2 is set by a timing circuitry to compensate for any change in the relative location between the two stimulation electrodes that may be desired. Preferably, the distance between the two stimulating electrodes is adjusted to be approximately between 0.1 and 1.5 mm. Preferably, the distal end of the needle of each stimulating electrode consists of a 100 82 m long exposed metal cone, with a 10 μm diameter tip. The needle segment connecting between its proximal end and its distal end is insulated, so as to limit current impulse generation to the vicinity of the distal end. Preferably, the magnitude of the second current impulse, S 2 , is between 1.25 and 1.5 times the threshold level of the excitable tissue. Preferably, the delay between the two impulses (which is equal to timing of S 2 minus timing of S 1 ) is between −10 mSec and +5 mSec, and the duration of each current impulse is approximately 100 μs. The propagation direction of the remaining DGEW can be switched by increasing the magnitude of the first stimulus, S 1 , above the threshold level of the excitable tissue, and decreasing the magnitude of the second stimulus, S 2 , below the threshold level of the excitable tissue. The distance between the two stimulating electrodes is set so that the two impulses interact with each other only in one desired direction, while preventing interaction in the opposite direction. Preferably, the device comprises a detector circuitry, linked to the aforesaid first and second control circuits of each stimulation electrode and to the timing circuitry, for detecting unwanted excitation waves in the excitable tissue which are above the threshold level. The device is operated automatically whenever an unwanted wave is detected. In response, an opposing impulse wave is generated. Said wave interferes with the unwanted one and reduces its magnitude below the threshold level, thereby causing the unwanted wave to decay. The device can reside outside of the excitable tissue with only the electrodes implanted within the tissue. Alternatively, the whole device can be implanted in the excitable tissue. The invention further comprises the use of the aforesaid device for suppressing malignant cardiac arrhythmias. The present invention is also directed to a method for medical treatment and suppression of malignant cardiac arrhythmias in patients, resulting from unwanted excitation waves generated and sustained in closed re-entry conductive paths in the heart of the patient, by generating unidirectional excitation waves for interacting with the unwanted excitation waves and canceling them. The method enables medical treatment and suppression of malignant cardiac arrhythmias in patients, resulting from unwanted excitation wave. Low-energy, asymmetrical excitation impulses are generated in two different locations in the myocardium. The first impulse has a magnitude below the threshold level of the myocardium tissue, and the second impulse has magnitude above the threshold level. The distance between the two locations, and the time of the generation of the impulses is determined, so that the passive electric depolarization generated by the first excitation impulse interacts with the propagating action potential generated by the second excitation impulse, thereby preventing the spreading of excitation wave in an undesirable directions. The remaining unidirectional excitation wave cancels the unwanted wave in its re-entry path. Preferably, one excitation impulse is generated with a delay in respect to the other excitation impulse. Both excitation impulses may also be generated concurrently. Let us call the impulses that travel in one direction “d impulses” and those that travel in the opposite direction “s impulses” and let us say that the unwanted impulse is a “d impulse”. Then one applies two electrodes A and B, wherein electrode A generates two impulses Ad and As above the threshold and B generates two impulses Bd and Bs below the threshold. Impulse As will interact with the unwanted impulse and these two impulses will cancel each other. Impulse Bd will decay. The distance between the electrodes and the timing of impulse generation are either such that impulse Ad interacts with impulse Bs before this decays, and the interaction generates a residual impulse that is below the threshold and therefore decays. However, alternatively, if the two electrodes are sufficiently close to one another, no impulses are generated between them, viz. there are no impulses Ad and Bs. In either case, no impulse thus remains to propagate through the heart tissue. Therefore, the method comprises: a—generating, by means of a first electrode, a first impulse above the threshold that propagates opposite to the unwanted impulse, whereby when it meets said unwanted impulse, the two impulses cancel one another; b—generating, by means of a second electrode a second impulse below the threshold, that propagates in the same direction as the unwanted impulse and decays; and c—choosing the distance between said electrodes and the timing of the impulse generation in such a way that the first electrode generates a third impulse above the threshold that propagates in a direction opposite to that of said first impulse threshold, while the second electrode generates a fourth impulse below the threshold that propagates in a direction opposite to that of said second impulse, whereby said third and fourth impulse meet and their interaction generates a residual impulse that is below the threshold and decays; d—provided that if said distance is small enough, no third and no fourth impulse are generated. The present invention also provides a method for localizing the pathological tissue (or pathways) that are responsible for arrhythmias. The location of the re-entry path of the unwanted excitation wave are identified from the direction of the remaining sub-impulse when this latter cancels the unwanted excitation wave, and destructive energy is delivered to the identified location. In the following description, it is assumed that the stimulation electrodes are positive; however, this is not to be construed as an absolute, and they could be negative. BRIEF DESCRIPTION OF THE DRAWINGS The above and other characteristics and advantages of the invention will be better understood through the following illustrative and non-limitative detailed description of preferred embodiments thereof, with reference to the appended drawings, wherein: FIG. 1 schematically illustrates an asymmetrical impulse shape employed according to a preferred embodiment of the invention; FIGS. 2A to 2 F schematically illustrate the initiation and development of a one-dimensional unidirectional DGEW in response to input excitation impulses, according to a preferred embodiment of the invention; FIG. 3 is a spatial illustration of the initiation and development of a two-dimensional unidirectional DGEW propagating in a ring-type path, according to a preferred embodiment of the invention; FIG. 4 schematically illustrates that in a two-dimensional excitable medium, under certain conditions, the unidirectional DGEW initiates, develops, and decays, according to a preferred embodiment of the invention; FIG. 5 schematically illustrates that, under different conditions, the unidirectional DGEW initiates, develops, and spreads, according to a preferred embodiment of the invention; FIG. 6 schematically illustrates the range of several tissue and environmental parameters, for which a unidirectional DGEW may be obtained, according to a preferred embodiment of the invention; FIG. 7 schematically illustrates a re-entry path in myocardium tissue; FIG. 8 schematically illustrates that unidirectional DGEWs could be obtained for several conditions, including those typical to an ischemic heart tissue; FIG. 9 schematically illustrates a typical prior art electrode arrangement for generating impulses in excitable tissues; FIG. 10 schematically illustrates the structure of a device for generating unidirectional DGEWs, propagating in an excitable tissue, according to a preferred embodiment of the invention; FIG. 11 schematically illustrates a typical structure of a stimulating needle, according to a preferred embodiment of the invention; FIG. 12 schematically illustrates the recording at two different locations of a DGEW propagating in heart tissue, in response to a single stimulation; and FIG. 13 schematically illustrates the generation of a unidirectional DGEW by the interference of the S 1 and S 2 stimuli, according to a preferred embodiment of the invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The functionality of excitable systems may be controlled and improved by applying electrical impulses of particular parameters at specific locations. By controlling the stimulating impulse characteristics and location, several desired responses may be obtained. One of these characteristics is the direction along which the DGEW propagates. Generating a unidirectional DGEW in an excitable medium, such as cardiac tissue, is carried out by exploiting an electrode, which is immersed in the excitable medium and excited with electrical energy delivered from a voltage or current source. Generally, an excitable medium is able to sustain electrical DGEWs generated in response to electrical stimuli. The feasibility and the shape of the generated, unidirectional DGEW are mainly affected by the characteristics of the excitable medium, as well as the structure of the stimulating electrode. For a better understanding of the present invention, an example (prior art) of a device for generating stimuli is shown in FIG. 9 . An electrical signal source 110 is connected to two insulated conductive needles 111 and 112 of the bipolar stimulating electrode 116 . Every conductive needle 111 and 112 consists of a metal tip 114 at its distal end, through which an excitation impulse is delivered. The rest of the conductive needle is insulated; and the two needles are covered by the insulating sleeve 113 . Electrode 116 is inserted into an excitable medium, until both the tips 114 are in electrical contact with the tissue. Since the tissue is electrically conductive, voltage applied between needles 111 and 112 causes a current to flow between tips 114 , which function as the two electric contacts of the electrode 116 . The current flows via the excitable medium, and its magnitude is determined by the impedance of the excitable medium and the contacts. Knowing the impedance, the current magnitude may be controlled by varying the applied voltage. Alternatively, the current can be “clamped” to a given value by usage of very low internal impedance current source. The current excites the excitable medium and a resulting response DGEW is generated. FIG. 10 schematically illustrates the structure of a device for generating a unidirectional DGEW, propagating in excitable tissue, according to a preferred embodiment of the invention. The device 130 comprises two positive conductive needles, 131 and 131 a (shown in FIG. 11 ), which are inserted into the excitable tissue at two different locations. Each positive conductive needle comprises a relatively sharp tip 134 at its distal end. The proximal end of the needle is connected to the positive contact of a power supply 135 by a suitable flexible insulated wire 136 . A negative conductive needle 137 forms a closed conducting current path through the excitable tissue, which is stimulated by the power supply 135 . The distal end 138 of the negative needle is implanted in a predetermined location in the excitable tissue. The proximal end of the negative electrode is connected to the negative contact of the power supply 135 . Each power supply 135 comprises a suitable control circuitry 139 for determining the required amplitude and duration of the voltage applied between the positive and negative electrodes, so as to force a current impulse to flow between each positive needle and its corresponding negative needle through the excitable tissue. According to a preferred embodiment of the invention, the control circuitry of the first power supply 135 a , which drives the first bipolar electrode 136 a , is set to generate a first current impulse S 1 with a magnitude that is lower than the threshold level of the excitable tissue. The threshold level (which can be found experimentally) is the current impulse magnitude, above which the tissue is excited and the impulse continuously propagates from cell to cell, each time exciting the next cell. Impulses below the threshold level cannot cause the continuously propagating DGEW along the tissue and these decay with time. The typical value of threshold level is approximately 7 Volts or 0.5 mA for 100 sec duration impulse. S 1 is below the threshold level and spreads electronically along the excitable tissue in all directions. The control circuitry 139 b of the second power supply 135 b , which drives the second bipolar electrode 131 b , is set to generate a second current impulse S 2 with a magnitude that is higher than the threshold level of the excitable tissue. The resulting DGEW initiates at the site where S 2 is located. According to a preferred embodiment of the invention, the first and second current impulses are generated with a predetermined delay in respect to each other. The required delay is determined in combination with the distance between the two electrodes, and is set by a timing circuitry 132 which is linked to both control circuits 139 a and 139 b , so that the wave initiated by S 2 cannot propagate actively towards S 1 and decays with time. However, it propagates freely in other directions. FIG. 11 schematically illustrates a typical structure of a conductive needle, according to a preferred embodiment of the invention. It consists of insulated part 133 , connecting between its distal and proximal ends. The distal end consists of a 100 μm long exposed metal cone 140 , ending with a 10 μm diameter tip 141 . The segment 133 connecting between its proximal end and its distal end is insulated, so as to limit impulse generation to the vicinity of the distal end. According to a preferred embodiment of the invention, the magnitude of the second current impulse provided by the second power supply 135 b is set to be between 1.25 and 1.5 times the threshold level of the excitable tissue. The time delay between the two stimuli is set by the timing circuitry 132 to values between −10 and +5 mSec (relative to the supra-threshold stimulus), and the duration of each impulse is set by the control circuitry 139 b to approximately 100 μsec. Of course, the propagation direction of the DGEW created by S 2 can be switched by increasing the magnitude of the first impulse above the threshold level of the excitable tissue, and decreasing the magnitude of the second impulse below the threshold level of the excitable tissue. According to a preferred embodiment of the invention, the device 130 may comprise a detector circuitry, linked to the control circuitry of each stimulating electrode and to the timing circuitry. This circuitry detects unwanted excitation waves in the excitable tissue which are above the threshold level. The detector circuitry detects unwanted waves through one or more sensing electrodes, which are implanted in predetermined locations in the excitable tissue. The device 130 is operated automatically whenever an unwanted excitation wave is detected by the detector circuitry. In response, a unidirectional DGEW of magnitude above the threshold level is generated by the device 130 and propagates in the excitable tissue. The generated unidirectional wave interferes with the unwanted wave and reduces its magnitude below the threshold level, thereby causing the unwanted excitation wave to decay. The device 130 may be located outside the excitable tissue and only the electrodes (i.e., the positive/negative and the sensing electrodes) implanted inside therein, or alternatively, the whole device 130 may be implanted in the excitable tissue. For instance, integrated circuit implementation technology can be used to obtain a miniature device. FIG. 12 schematically illustrates the recording of a DGEW propagating in the heart tissue at two different locations, in response to a single stimulus. The simulation impulse S is applied at point a in the excitable tissue 150 by a simulation electrode. The stimulation impulse S is a rectangular current impulse of 100 sec duration and approximately 10 mV amplitude (i.e., 1.5 times above the threshold level of the excitable tissue). The response DGEW propagates along the excitable tissue 150 from the stimulation point a, to the first recording point b, located 2.6 mm apart from point a, and then to the second recording point c, located 6.1 mm apart from point a. The response wave is sampled at points b and c, shown by the lower and upper traces, respectively. Both traces indicate normal propagation in clockwise direction along the excitable tissue 150 . FIG. 13 schematically illustrates the generation of a unidirectional DGEW by interference of a wave propagating in one direction in an excitable tissue, in response to stimulation, and additional stimulation at a different location, according to a preferred embodiment of the invention. Two stimulation impulses, S 1 and S 2 are applied at points d and e, respectively, in the excitable tissue 150 by two simulating electrodes, located at a distance greater than 1.5 mm between them. The stimulation impulse S 2 , which is above the threshold level, is first applied alone. The two upper traces (solid lines) show the response. The response wave is split into two similar waves: one that propagates along the excitable tissue 150 from the first stimulation point d, to the recording point b, and the other one that propagates along the excitable tissue 150 in the opposite direction from the first stimulation point d, to the other recording point c. The right “dip” in each trace indicates that the response wave propagates in the excitable tissue 150 in both directions. The stimulation impulse S 1 , which is below the threshold level is applied at a predetermined delay, which is longer than the refractory period of the excitable tissue 150 following the first stimulation impulse S 2 . The two lower traces (dashed lines) show the response to the first stimulation signal S 2 that propagates in both directions. Delivery of the second stimulation impulse S 1 prevents a wave initiated by the second S 2 to propagate in one direction. Apparently, the local electronic response to S 1 creates an obstacle. The result is that the impulse which has been split from S 2 and propagated toward point b, is canceled by S 1 , since no “dip” in the trace recorded at point b. On the other hand, a “dip” appears in the trace recorded at point c, which indicates that there is propagation in this direction in response to S 2 . In fact, S 1 “canceled” the propagation of the wave elicited by S 2 in one direction, and enabled the propagation of the wave elicited by S 2 in the opposite direction. Hence, a unidirectional impulse is obtained by setting the distance and timing of the stimuli S 1 and S 2 . According to a preferred embodiment of the invention, a unidirectional DGEW is generated by using the electrodes immersed in excitable tissue, with a specific spatially and temporary asymmetrical current application. The generated unidirectional wave is sustained by the excitable tissue and propagates along the conduction path. Excitable systems may be described by FitzHugh-Nagumo set of differential equations (FitzHugh-Nagumo model is disclosed, for example, in “Biological Engineering, R. FitzHuge, H. P. Schwan et al eds., McGraw Hill, N.Y. 1969”): {dot over (v)}=D∇ 2 ·v+f(v,w)+I(t,{right arrow over (r)}) {dot over (w)}=g(v,w) wherein v represents the potential, D is the diffusion constant, w represents the refractivity and I(t,{right arrow over (r)}) is the input current. The functions f(v,w) and g(v,w) are given by: f=v (v−a)(1−v) g=c (v−dw) wherein α is an excitability parameter, c represents the ratio between fast and slow time constants and d represents the resistivity of the cell. Spatial propagation basically depends on the value of the diffusion constant D and on the input current, I. In the model of a preferred embodiment of the invention, the parameters D=1 and d=3 are held constant, and all other parameters may be varied. Therefore, it is desired that the main effect will be controlled mainly by the input current. The input current is given by: I (t,{right arrow over (r)})= I 1 (t)· I 2 ({right arrow over (r)}) ps wherein I 1 (t) is a short time dependent component and I 2 ({right arrow over (r)}) is the spatial component, which depends on the shape of the stimulating electrode. The optimal form of I 1 (t) has been obtained for prior art external pacing and defibrillation techniques. Therefore, in the present invention the optimal shape of I 2 ({right arrow over (r)})is sought. Since a symmetrical form of I 2 ({right arrow over (r)}) leads to an (ineffective) bi-directional impulse, an asymmetrical form should be exploited to obtain the desired unidirectional DGEW. FIG. 1 schematically illustrates an asymmetrical impulse shape I 2 ({right arrow over (r)}) employed according to the model of a preferred embodiment of the invention. Each part of the asymmetrical input impulse (of the pair) is used to excite a corresponding contact of a dual needle electrode, with different excitation current at each needle. The magnitude and duration of each part of the asymmetrical pair, as well as the timing between S 1 and S 2 , are appropriately controlled to obtain a unidirectional DGEW in response to this type of stimulation. The S 1 component may be a short spatial square wave or an impulse (δ function). The response wave shape depends on the magnitude of the S 2 component and on the ratio between the magnitudes of S 2 and S 1 . Input impulses of very small magnitude will not cause any propagating wave response. Above a predetermined threshold, a unidirectional DGEW or a bi-directional wave is elicited, according to the ratio between the magnitudes of S 1 and S 2 . In the model of a preferred embodiment of the invention (FIG. 1 ), the input impulse consists of two square impulses, of magnitudes h 1 and h 2 and widths l 1 and l 2 , respectively, spaced apart by a distance l 3 . In the following calculation we assumed that l 3 =0 and that A 1 =h 1 l 1 <A th , and l 2 may vary. According to this model of a preferred embodiment of the invention, two constants, α and β which determine the response impulse resulting from an input impulse, may be defined. For an input impulse for which 0<h 2 <α, no propagating response impulse is obtained. For α<h 2 <β, the response impulse is a unidirectional DGEW, and for h 2 >β, the response impulse is a bi-directional impulse. For example, if l 1 =12, l 2 =4 and h 1 =0.16, values of α=0.353 and β=0.403. On the other hand, if l 1 =l 2 =8 and h 1 =0.16, values of α=0.252 and β=0.262. Therefore, the range of h 2 for which the response impulse is a unidirectional DGEW increases with increasing l1/l2 ratio. The required A 1 (=h 1 l 1 ) values for generating a unidirectional DGEW are smaller for l 1 /l 2 =3 than for l 1 /l 2 =1. Hence, by using asymmetrical input impulse (i.e., l 1 >l 2 ), a unidirectional DGEW response is more easily obtained. FIGS. 2A to 2 F schematically illustrate the initiation and development of a one dimensional unidirectional DGEW response to a pair of input excitation impulses as a function of distance for several time points, according to the model of a preferred embodiment of the invention. At t=0, two input rectangular impulses are initiated, with almost no spacing distance (l 3 =0). FIG. 3 is a spatial illustration of the initiation and development of a two dimensional unidirectional DGEW response propagating in a ring-type path, to a pair of input excitation impulses in two dimensional (x-y) plane for several time points, according to the model of a preferred embodiment of the invention. Periodic boundary conditions exist only in x direction. Finite (un-periodic) boundary conditions, v=w=0, exist in y direction. The resulting response impulse shape is a “band” in the x-y plane. The input impulse has a finite width in the y direction and asymmetrical shape in x direction. The response in the x direction is similar to the one-dimensional response of FIG. 2 . FIG. 4 schematically illustrates the initiation, development and decay of a two-dimensional, unidirectional DGEW response propagating in a two-dimensional excitable medium, to a pair of input excitation impulses in two dimensional (x-y) plane, according to the model of a preferred embodiment of the invention. Here, the ratio c between fast and slow time constants is relatively high, and hence, unidirectional DGEWs, as well as bi-directional response waves, shrink and decay. The larger c is, the closer is the tissue to the pathological state, like ischemia (as will be described below). FIG. 5 schematically illustrates the initiation, development and spread of a two-dimensional, unidirectional DGEW response propagating in a two-dimensional medium, to a pair of input excitation impulses in two dimensional (x-y) plane, according to the model of a preferred embodiment of the invention. Here, tissue properties are different than those of FIG. 5 . The envelope of this “plane-wave” propagating response impulse is a slowly increasing monotonic function. FIG. 6 schematically illustrates the range of several refractory period parameters, for which a unidirectional DGEW response may be obtained, according to the model of a preferred embodiment of the invention. The unidirectional DGEW response region is plotted in the a-c plane, for fixed values of the parameters d, h 1 and h 2 , and for l 1 =l 2 =25 (solid line). The upper boundary of the obtained region coincides with a portion of the boundary of the excitable region (i.e., no impulses can propagate for higher values of the parameter c). The unidirectional DGEW response region is further expanded (dashed line) by changing the values of l 1 and l 2 to 15 and 35, respectively. FIG. 7 schematically illustrates a re-entry path in myocardium tissue. Note that in a case when a unidirectional DGEW, generated in accordance with the present invention, could interrupt the re-entry loop, it would provide information about the exact location of the latter. FIG. 8 schematically illustrates the regions where unidirectional DGEWs are obtained for several conditions, which resemble ischemia. The results are shown in the l 1 -h 1 domain for three different values of c, with other parameters held fixed: α=0.139, d=2.54, D=1, l 2 =25 and h 2 =0.4. From the figure, it is clear that obtaining unidirectional DGEWs becomes easier with increasing value of c (i.e., the unidirectional DGEW region increases at more ischemic conditions). According to a preferred embodiment of the invention, an easy and accurate localization for a re-entry path in an excitable tissue is found by using an invasive dual contact electrode, penetrate into the likely tissue, with the contacts spaced by the distance l 3 . An asymmetric input impulse, such as the one shown in FIG. 1 above, is applied at the needles of the electrode and a corresponding unidirectional DGEW is generated. The generated unidirectional DGEW totally nulls the unwanted excitation wave oscillating in the re-entry path, if the unidirectional DGEW is generated and propagates in the main track of the re-entry path. If the unidirectional DGEW is generated and propagates in a secondary (or an auxiliary) track of the re-entry path, only temporary cancellation is achieved, followed by an eventual reset. In both cases, the total amount of energy delivered to the heart tissue is small (on the order of 10 mJ) and both pain and damage to the heart are avoided. Therefore, locations for re-entry paths are pinpointed whenever cancellation is obtained. Hence, after the re-entry path is identified and located, the re-entry region may be accurately ablated using any known technique, such as Radio-Frequency (RF) ablation. According to a preferred embodiment of the invention, after identifying and locating re-entry paths in a patient's heart, such dual contact electrode is implanted in the patient's heart at that location. A unidirectional DGEW is generated by applying an input asymmetrical stimulus to the needles of the implanted electrode from an external or implanted circuitry, whenever actual or impending malignant cardiac arrhythmia is identified. The above examples and descriptions have of course been provided only for the purpose of illustrations, and are not intended to limit the invention in any way. As will be appreciated by the skilled professional, the invention can be carried out in a great variety of ways, such as using non-rectangular excitation impulses, employing more than one technique than those described above, treating cardiac arrhythmias, all without exceeding the scope of the invention.	A device for canceling unwanted excitation waves in an excitable tissue, particularly those causing cardiac tachyarrhythmias, which comprises circuitry for generating a unidirectional Device-Generated Excitation Wave (DGEW) in the tissue. The device comprises first and second stimulation electrodes, each fed by a power supply, which generate current impulses having magnitudes respectively lower and higher than the threshold level of the excitable tissue. The positions and activation timing of the electrodes are set so that the two impulses interact with each other only in one desired direction and every impulse except the desired DGEW decays. A method is also provided for suppressing malignant cardiac arrhythmias, caused by an unwanted excitation wave, which comprises generating in two different locations of the myocardium two excitation impulses having magnitudes respectively lower and higher than the threshold level of the excitable tissue, determining the distance between said locations and the time of the generation of the impulses so that a unidirectional DGEW is generated, and applying the DGEW to the myocardial tissue to cancel the uwanted excitation wave in its re-entry path.	0
CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the priority, under 35 U.S.C. § 119, of German Patent Application DE 10 2007 034 880.2, filed Jul. 24, 2007; the prior application is herewith incorporated by reference in its entirety. BACKGROUND OF THE INVENTION Field of the Invention [0002] The present invention relates to a method for developing printing plates in a printing press having at least one printing unit. The invention also relates to a printing press for carrying out the method. [0003] In offset printing presses, printing plates which carry a printing image for a color separation are each situated in an individual printing unit. The printing plates are written in accordance with the color separations in order to apply the printing image to the printing plates. This writing of the printing plates takes place during the exposing process which can be performed, for example, through the use of a laser. Either the regions which print later or the regions which do not print later are modified by the exposure of the printing plate. The regions which are in each case not exposed and not written then have to be treated in a developing step, as a result of which finally the different surface quality of unwritten and written regions is set. In this case, the surface of the unwritten regions after the developing process usually has the property that those regions are ink-repelling, while the written regions of the printing plates are ink-accepting. Due to the supply of ink in the printing unit, the printing plates are then loaded in each case with the corresponding ink and transfer the printing image onto the blanket cylinder in a manner which is inked in this way. The blanket cylinder in turn interacts with an impression cylinder in the press nip. In this press nip, the ink is then transferred onto sheets or webs which are to be printed. [0004] The printing plates are usually exposed outside the printing press in printing plate exposers. However, there are also printing presses which operate according to the principle of direct imaging (DI technology), in which the exposing device is situated in the printing unit in the immediate vicinity of the plate cylinder having the printing plate. In that case, the printing original is transmitted digitally in color separations to the printing plate exposer in the printing unit and is usually written there onto the printing plates of the printing plate cylinders through the use of a laser on site. Since the printing plates are not written until they are in the machine, as a consequence in those machines the printing plate also has to be developed in the machine. In the case of printing plates which are exposed outside the printing press, the printing plates can in turn be developed outside the printing press, or in the printing press. If the printing plates are developed in the printing press, that takes place by the application of the ink and dampening solution. Printing plates of that type which are to be developed in the machine are also called processless printing plates. [0005] A printing press of that type for image setting in the machine is known from U.S. Patent Application Publication No. US 2007/0095232 A1. In that case, each printing unit has a laser image setting unit which is disposed in the region of the plate cylinder. The printing plates which are clamped on the plate cylinder can be written by way of the laser image setting device. Those regions of the printing plates which are written by way of the laser harden, while the unwritten regions are made blank and ink-repelling by a developing process in the machine through the use of ink and dampening solution. In order to improve the image setting through the use of laser, the printing units are covered with respect to incident light. That ensures that no light or only a little light having a wavelength which is shorter than 450 nanometers reaches the printing plates. Undesired reactions of the printing plate surface with incident daylight are therefore avoided. [0006] However, during the developing of printing plates in the printing press through the use of the application of dampening solutions and ink, problems frequently result in reality, since either insufficient dampening solution or too much ink is applied. The application of dampening solution and ink usually takes place simply by the startup of the printing press for printing operation. As a result, however, the surface of the printing plate is often not developed in an optimum manner in the printing press, as a result of which the printing image later does not correspond to quality requirements. For that reason, many printing companies are very skeptical of the technology of developing in the printing press known as DoP (development on press). A solution to that problem cannot be gathered from U.S. Patent Application Publication No. US 2007/0095232 A1. SUMMARY OF THE INVENTION [0007] It is accordingly an object of the invention to provide a method for developing printing plates in an offset printing press and a printing press for carrying out the method, which overcome the hereinafore-mentioned disadvantages of the heretofore-known methods and printing presses of this general type and which make it possible to develop a surface of the printing plate in the printing press in a manner which is reliable and reproducible for a printer. [0008] With the foregoing and other objects in view there is provided, in accordance with the invention, a method for developing printing plates in a printing press having at least one printing unit. The method comprises loading an imaged, undeveloped printing plate with dampening solution before a start of printing for dampening in at least one printing unit of the printing press for an active duration corresponding at least to one and one half times a time duration or number of machine revolutions provided before a start of printing when using an already developed printing plate in the same printing press. Although particular printing speeds are mentioned below, in order to obtain the time or speed in revolutions per minute, the printing speed and the format of the press, that is the concrete length of the sheet and the printing speed, must be considered. Since this is format-dependent, a particular time cannot be given as an example. [0009] With the objects of the invention in view, there is also provided a printing press, comprising at least one printing unit, a plate cylinder in the printing unit for receiving a printing plate, an inking unit in the printing unit, a dampening unit in the printing unit, and a control computer acting on a setting of the inking unit and the dampening unit and selectively carrying out a special program for dampening and developing exposed printing plates to be developed for an operating state before continuous printing. The special program for developing exposed printing plates is switched off automatically at a start of continuous printing. [0010] The printing press according to the invention and the method according to the invention are suitable for use in all offset printing presses which make it possible to use printing plates that are to be developed in the printing press. This extends both to sheet-fed offset printing presses as well as to web-fed offset printing presses. While the normal print setup procedure which leads to the known problem is performed in the conventional DoP method for developing the exposed printing plates in the machine, the processes before preprinting operation are adapted and predefined specifically to the developing of the exposed printing plates in the printing press according to the present invention. If a newly imaged processless printing plate is inserted into the printing press or imaged in the machine in the case of a printing press having DI technology, the printing plate is thus provided first of all with dampening solution before the start of printing during an active duration which is at least one and one half times the time duration or number of machine revolutions more than the time duration for dampening when an already developed printing plate is used in the same printing press. A distinction is therefore made for the first time during startup of the printing press, in relation to the dampening, between the use of a newly imaged and not yet developed printing plate and an already developed printing plate. As a result of the time duration which is at least one and one half times as long or a corresponding number of machine revolutions, the dampening solution can act on the printing plate for a longer time than is possible during the conventional startup of the printing press. As a result, the upper plate layer which is to be removed during the developing process in the printing or nonprinting regions can swell in an improved manner, as a result of which reliable removal of the layer is ensured. In principle, in DoP technology, the surface of the plate layer is made to swell through the use of dampening solution, while the swollen plate layer is removed through the use of printing ink which is applied and the swollen plate layer is pulled off by adjacent rolls or cylinders. As a result of the thorough and considerably longer action of the dampening solution on the printing plate, however, the removal of the uppermost plate layer is improved enormously, as a result of which the print quality at the beginning of continuous printing is not substantially poorer than printing plates which have been developed conventionally outside the printing press. [0011] In accordance with another mode of the invention, the active duration of the dampening solution for dampening the printing plate is divided into one or more separate dampening phases and into dampening before the start of continuous printing. The only important aspect is that the dampening overall takes a considerably longer time in the case of an undeveloped printing plate than in the case of an already developed printing plate. [0012] In accordance with a further mode or first refinement of the invention, a small amount of ink is added to the dampening solution during developing of the printing plates in the printing press for an emulsion including ink and dampening solution. The use of an emulsion including ink and dampening solution proves advantageous, in particular, when the printing unit having an inking unit and a dampening unit has been washed previously after a print job change. As a result of the washing of the printing unit, there is then no longer any printing ink in the inking and dampening unit. It has proven favorable, however, for the developing process, if a small amount of ink is mixed with the dampening solution. If the inking and dampening unit has been washed, an input of ink has to be carried out before printing. Toward the end of the ink input, the dampening unit is also switched on and the printing plate is dampened by throwing on the dampening solution applicator roll. The processless plate comes into contact for the first time with dampening solution and the nonprinting points of the printing plate swell under the influence of the dampening solution and the dampening solution applicator roll. In order to obtain a favorable emulsion for improving the swelling process for the further developing process, the inking unit can be brought into connection with the dampening unit for a brief time, as a result of which a small amount of ink passes into the dampening unit, which is required for the formation of the emulsion including dampening solution and ink. Subsequent further dampening of the printing plate with the ink/dampening solution emulsion, which includes predominantly dampening solution, favors the further swelling of the plate. When the ink applicator rolls are thrown on, the swollen nonprinting image regions are removed from the printing plate relatively quickly by the ink and the plate runs free. [0013] If the printing unit is not washed, a small amount of ink is automatically in the dampening unit, as a result of which the same conditions result by the addition of pure dampening solution. As a result of the introduction of an emulsion including ink and dampening solution into the washed printing unit, only the same state is therefore produced, as would also be produced in the case of an unwashed printing unit. However, it is very important in this case that the amount of ink remains very small, as a result of which the amount of dampening solution predominates considerably in every case. [0014] In accordance with an added mode of the invention, in order to produce the emulsion including ink and dampening solution in the case of a washed printing unit, the inking unit can be thrown on briefly for a fraction of a revolution during the developing of the printing plate before the start of continuous printing, as a result of which the emulsion including a little ink and a large amount of dampening solution can be produced easily on the printing plate. The inking unit is thrown on briefly in this way during the swelling process and is not to be confused with the ink application which takes place after the swelling process in order to remove the layer which is to be pulled off from the printing plate. The process of swelling is to be carried out for such a long time that the printing plate is not clogged later by the application of ink during removal of the layer. This can be ensured only by sufficiently long dampening with a sufficient amount of dampening solution. [0015] In accordance with an additional mode of the invention, ink is introduced for pulling off the developed plate layer before the start of continuous printing by throwing the inking unit onto the printing plate. In order to remove the swollen layer, the inking unit is thrown on temporally very closely to the start of continuous printing, so that an ink layer results on the sufficiently damp printing plate. As a result of the contact of the ink layer with the adjacent rolls of the inking and dampening unit or of the blanket cylinder, the uppermost swollen plate layer is then removed and the actual developing process is completed. The ink layer is required, in order to produce the corresponding pulling action on the swollen surface by the adjacent rolls and cylinders. As a result of the sufficiently long predampening process, the removal of the layer can be concluded after a few revolutions of the plate cylinder. In this case, as a rule, the printing plate is inked for three machine revolutions, before continuous printing begins. For continuous printing, the plate cylinder is then thrown onto the blanket cylinder, the paper run of sheet or web is switched on and the blanket cylinder is connected to the print medium. [0016] In accordance with yet another mode of the invention, advantageously the dampening for developing the printing plate is performed at the maximum possible or an increased application of dampening solution of the dampening unit. In order to make the swelling process as short and effective as possible, regulators for the application of dampening solution are to be set to the maximum possible amount of dampening solution during developing of the printing plate. This ensures that sufficient dampening solution is applied in as short a time as possible to the printing plate which is to be developed. [0017] In accordance with yet a further mode of the invention, a further advantage results by virtue of the fact that the dampening for developing the printing plate is performed with a quantity of dampening solution which is variable over time or as a function of the machine revolutions. The amount of dampening solution can therefore be adapted by the control computer of the printing press in an optimum manner to the developing process through the use of characteristic curves and as a function of the machine speed. [0018] In accordance with yet an added mode of the invention, a further advantage results by virtue of the fact that the application of dampening solution takes place at relatively low printing speeds, in particular between 2,000 and 9,500 sheets per hour in sheet-fed printing presses. An operating speed of the printing press which is considerably slower than continuous printing speeds of over 18,000 sheets per hour has improved the application of dampening solution further in tests. The same reduced speed has also proven favorable during the short application of ink for pulling the layer off of the printing plate. The pulling off of the layer by the ink applicator rolls which are thrown onto the plate cylinder preferably takes place without paper running being switched on, as a result of which no unnecessary waste paper is produced. [0019] In accordance with yet an additional mode of the invention, after developing of the printing plates, all of the printing units of the printing press are switched over to continuous printing at the same printing speed. Since, in this case, all of the printing units are switched over to continuous printing at the same printing speed, the same states also result on all of the printing units during removal of the layer after the application of ink. In the same way that the application of dampening solution or the application of the emulsion including dampening solution and ink also takes place if possible at low printing speeds between 2,000 and 9,500 sheets per hour in sheet-fed printing presses, the switchover to continuous printing operation should also take place at a relatively low printing speed between 2,000 and 9,500 sheets per hour in sheet-fed printing presses. The removal of the layer during switchover to continuous printing operation is more successful at this relatively low printing speed. [0020] In accordance with again another mode or particularly advantageous refinement of the invention, the printing press has a control computer and the control computer acts on the settings of the inking unit and the dampening unit in the printing press, and the control computer has the selection possibility of a special program for dampening and developing exposed printing plates for the operating state before continuous printing. This ensures that the developing of the exposed printing plates in the machine does not take place with the amount of dampening solution and ink which is required during normal startup, but rather that sufficient time is given for the required swelling process for correct removal of the layer in the unexposed or exposed regions of the printing plate which is to be developed. When the printer has inserted a new exposed printing plate into the printing press, he or she can select the program “DoP” which automatically makes the corresponding steps possible for optimum swelling and subsequent removal of the layer. This has the great advantage that this program is reproducible and the printer does not himself or herself have to set a halfway suitable application of dampening solution and ink for developing the printing plate from the innumerable number of settings for the inking and dampening unit. This avoids a developing process of the printing plate which is set incorrectly and is affected by faults with immanent quality problems, and makes the use of the DoP printing plates interesting for the first time for most printers. [0021] In accordance with again a further mode of the invention, a sensor is provided in the printing press for distinguishing between a developed and an undeveloped printing plate in at least one printing unit. A sensor of this type can sense the surface of the inserted printing plate and determine whether or not there are regions on the printing plate which have already been removed. In this case, the sensor would detect an already developed printing plate, as a result of which the special program for developing the printing plate does not need to be used. If, however, the sensor cannot detect a removed layer on the printing plate, it is to be assumed that it is a new exposed but not yet developed printing plate, for the developing of which the special program for dampening and developing has to be used. The special program for developing the printing plate automatically in the printing press can be carried out as a function of the detection results of the sensor. As an alternative, there can also be provision for the printer to be given the indication first of all on a display screen optically, or acoustically in another embodiment, that a new printing plate which has not yet been developed has been inserted and the selection of the special program for developing is offered to the printer. The printer can then start the special DoP program by inputting an acknowledgement. It goes without saying that a purely manual selection of printing units by the operating staff is also conceivable, with the special DoP program then being carried out in the manually selected printing units. However, this process is not protected against false inputs by the printer. [0022] In accordance with again an added mode of the invention, the special program for developing the exposed printing plate is switched off automatically with the start of continuous printing. Since the special program is appropriate only in the case of new printing plates which have not yet been developed, the automatic switching off after the start of continuous printing can ensure that the special program for developing is not started accidentally and unnecessarily in the case of a new print start with the same printing plate or another printing plate which has already been developed. Even if the printer forgets that he or she does not need the special program in the case of an already developed printing plate, this embodiment ensures automatically that the special program is not accidentally used in the case of a developed printing plate. [0023] In accordance with again an additional mode of the invention, the printing press has a plurality of printing units for receiving printing plates which have been developed outside and inside the printing press, and the special DoP program for developing the printing plate in the printing press is selected by the control computer through the use of the sensors in the printing units, only in each case for printing units having inserted printing plates which are to be developed. Printing plates which are to be developed both outside and inside the printing press can be used in a printing press of this type with high operational security. Since the sensor can distinguish between developed and undeveloped printing plates, the printer does not have to worry about the correct treatment of the printing plates. The special DoP program for developing printing plates is started as a function of the plate which is detected by the sensors only in the respectively relevant printing unit, automatically or after an indication to the printer in the case of the printing plates which have not yet been developed. However, the special program is not required and is also not used in the printing units having printing plates which have been developed outside the printing press. Operating errors by the printer are therefore reduced to a minimum and the reliable operation of different printing plates in a printing press is also ensured. [0024] In accordance with a concomitant mode of the invention, the sensor or an additional camera can also be used for monitoring a coat removal process during developing of the printing plate. If insufficient coat removal is determined, the control computer can add more dampening solution in the future or slow down the pulling off of the layer, until the printing plate is clean, and thus intervene in the developing process in an optimizing manner. [0025] Other features which are considered as characteristic for the invention are set forth in the appended claims. [0026] Although the invention is illustrated and described herein as embodied in a method for developing printing plates in an offset printing press and a printing press for carrying out the method, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. [0027] The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING [0028] FIG. 1 is a diagrammatic, longitudinal-sectional view of a multiple color sheet-fed offset printing press, a perspective view of a control computer and a side-elevational view of a connected printing plate exposer; [0029] FIG. 2 is a flow chart showing a selection possibility of a special DoP program for developing printing plates in the printing press; [0030] FIG. 3 is a flow chart showing operations during developing of a printing plate in the printing press; [0031] FIG. 4 is a diagram of a first variant of a special DoP program for developing printing plates in the printing press with extended predampening; [0032] FIG. 5 is a diagram of a second variant of a special DoP program for developing printing plates in the printing press with separate dampening and extended predampening; and [0033] FIG. 6 is a diagram of a third variant of a special DoP program for developing printing plates in the printing press with separate plate dampening and coat removal. DETAILED DESCRIPTION OF THE INVENTION [0034] Referring now to the figures of the drawings in detail and first, particularly, to FIG. 1 thereof, there is seen a sheet-fed offset printing press 1 having four printing units 2 . Each of the four printing units 2 has an inking unit FAW and a dampening unit 14 . Plate cylinders 5 in the printing units 2 are loaded with printing ink during printing operation from the inking unit FAW through inking unit rolls 16 . Moreover, each of the printing units has a dampening unit 14 in order for it to be possible to influence the consistency of the printing ink in the inking unit FAW. The dampening unit 14 dispenses dampening solution to the inking unit FAW, in order for it thus to be possible to change the consistency of the ink. The inking unit FAW and the dampening unit 14 can be thrown separately onto the plate cylinder 5 , and the dampening unit 14 and the inking unit FAW can also be thrown off one another. The plate cylinder 5 carries a printing plate 10 which contains the color separation for the respective printing unit 2 . The color separations on the printing plates 10 of the printing units 2 are produced in a prepress stage by breaking the printing original down into individual printing colors. There is a printing plate exposer 12 in the prepress stage for exposing the printing plate 10 with the respective color separation. Printing regions of the printing plate 10 are written through the use of a laser in this printing plate exposer 12 , as a result of which the properties of the surface in the printing regions change. After writing in the printing plate exposer 12 , the printing plates 10 can be clamped onto the plate cylinders 5 in the printing press. In the case of processless printing plates according to the DoP principle, developing, that is to say removal of the upper layer of the printing plate 10 in the nonprinting regions, takes place in the printing press 1 . [0035] In order to remove the layer in the nonprinting regions on the printing plate 10 , the printing plate 10 is dampened with dampening solution from the dampening unit 14 . This takes place for at least one and one half times as long as the time duration or as high a number of revolutions in the printing press 1 as is the case in printing plates 10 which have already been developed fully. As a result of this considerably extended dampening which can certainly also be carried out for four to five times as long as in the case of the developed plates 10 , the surface of the printing plate 10 swells in the unexposed regions. The surface which is swollen in this way can be removed from the printing plate 10 by an application of ink from the inking unit FAW. As a result of the adhesion of the ink on the uppermost layer of the processless plate 10 and in turn the adhesion of the ink on a blanket cylinder GT, the swollen up layer of the printing plate 10 is torn off and thus removed after a few revolutions of the printing press 1 . As a rule, three machine revolutions are sufficient before continuous printing operation begins. In continuous printing operation, the printing plate 10 on the plate cylinder 5 is supplied with sufficient printing ink from the inking unit FAW. This printing ink is transferred onto the surface of the blanket cylinder GT when the blanket cylinder GT is thrown on. The blanket cylinder GT is in turn thrown onto an impression cylinder 3 during printing operation, as a result of which the ink from the blanket cylinder GT can be transferred onto printing material 7 in a press nip 11 between the impression cylinder 3 and the blanket cylinder GT. [0036] In the sheet-fed printing press 1 , the printing materials 7 are removed from a feeder 6 and are transported over cylinders through the individual printing units 2 . The sheet-fed printing press 1 has a delivery 4 , located after the last printing unit 2 , in which the finished printed sheets 7 are deposited. A drive motor for the sheet-fed printing press 1 and actuating motors in the dampening unit 14 and the inking unit FAW can be actuated through an operating desk 9 having a control computer. The control computer in the operating desk 9 is configured in such a way that it can perform the necessary regulating operations largely automatically, in particular on the dampening unit 14 and the inking unit FAW. The operating staff can perform settings on the printing press 1 and read off the operating state through a display screen. To this end, the operating desk 9 is connected to the electronic control devices of the printing press 1 through a communications link 8 . Furthermore, the operating desk 9 is connected to the printing plate exposer 12 in the prepress stage through a communications link 8 . In this way, the printing press 1 can also exchange data with the prepress stage through the use of the operating desk 9 . Moreover, the control computer in the operating desk 9 contains a special control program for removing the unexposed layer on processless printing plates 10 . The printer may initiate this special DoP program manually on the operating desk 9 if he or she has inserted an exposed but not yet developed printing plate 10 into one of the printing units 2 . Alternatively, there is a sensor 15 in each of the printing units 2 , which senses the inserted printing plates 10 optically and detects an exposed but not yet developed printing plate 10 due to changed surface properties. If the sensor 15 reports a printing plate 10 of this type to the operating desk 9 , the operator receives an indication on a display screen on the operating desk 9 that he or she should start the special DoP program for removing the layer in the unexposed regions for this printing unit 2 . The computer in the operating desk 9 can also be configured in such a way that the special DoP program for removing the layer in the unexposed regions is carried out automatically when a not yet developed printing plate 10 is detected by the sensor 15 in the relevant printing unit 2 . Furthermore, there is a camera 13 in the printing unit 2 in FIG. 1 . The camera 13 is connected to the operating desk 9 having the control computer. This camera 13 monitors the removal of the developed layer from the printing plate 10 , as a result of which the control computer in the operating desk 9 can optimize the various parameters using the data of the camera 13 during dampening, developing and pulling off of the layer from the printing plate 10 through the use of printing ink. [0037] FIG. 2 indicates the operation during the selection of the special DoP program for removing the layer and for developing the plate 10 . Either the printer informs the control computer in the operating desk 9 manually that he or she has inserted a new undeveloped printing plate 10 into one of the printing units 2 , or the insertion of a plate of this type is detected automatically by the sensor 15 in the printing unit 2 . If a printing plate 10 of this type is detected, the special DoP program for removing the layer is used. A plurality of variants of this program will be described in greater detail with the aid of the other figures. If, however, there are only printing plates 10 which have already been developed in the printing units 2 of the printing press 1 , the normal standard program starts, by way of which the sheet-fed printing-press 1 is started. [0038] According to FIG. 3 , the special DoP program for removing the layer includes a plurality of processes. In contrast to normal startup of the printing press 1 with developed printing plates 10 , an adapted input of ink and an adapted ink presetting are performed in the case of undeveloped processless printing plates 10 . As its core, the DoP program includes a special predampening process which lasts a relatively long time and by way of which the swelling of the surface of the printing plate 10 is ensured sufficiently. In order to remove the swollen layer in the unexposed regions on the printing plate 10 , the surface of the printing plate 10 is inked briefly, as a result of which the inked swollen regions come into contact with the ink applicator rolls 16 of the inking unit FAW and the layer of the printing plate 10 can be pulled off and the printing plate is thus developed. After developing of the plate 10 on the plate cylinder 5 in the printing units 2 , the plate cylinder 5 is brought into contact with the blanket cylinder GT and the blanket cylinder GT is thrown onto the impression cylinder 3 . Before this, paper running is switched on, as a result of which the first printing sheets 7 reach the press nip 11 in the printing units 2 before the impression cylinder 3 and the blanket cylinder GT are thrown onto one another. Continuous printing operation is therefore achieved and the production of the printing materials 7 can begin. [0039] A first variant of a program for removing the unexposed upper layer of the printing plate 10 can be gathered from FIG. 4 . As is also the case in the following variants, a time axis t extends from the left to the right in the developing phase of the printing plate 10 and the start of continuous printing. The dampening unit 14 and the ink rolls 16 of the inking unit FAW in a printing unit 2 which are switched on and off from time to time during developing of the printing plate 10 are listed from top to bottom. Settings of the amount of dampening solution in the dampening unit 14 are performed through the use of a potentiometer Poti on the operating desk 9 of the printing press 1 . In the first variant 1 in FIG. 4 , first of all dampening is carried out with the maximum application of dampening solution for a relatively long time duration or a relatively high number of machine revolutions, which is also called predampening, in order to make the nonprinting layer of the plate 10 swell. To this end, the setting of the potentiometer Poti on the dampening unit 14 is 100%. Directly thereafter, the setting of the potentiometer Poti is reduced and the swollen plate layer is pulled off when the ink applicator rolls 16 are thrown on. The printing emulsion including dampening solution and ink is then set for continuous printing operation. Continuous printing then begins after a few revolutions of the plate 10 on the plate cylinder 5 . [0040] In the second variant in FIG. 5 , first of all predampening is carried out with the maximum application of dampening solution. To this end, the setting of the potentiometer on the dampening unit 14 is 100%. After a relatively short time, the application of dampening solution is reduced to approximately 50% for the continuous printing setting of the potentiometer Poti. Subsequently, the normal program for preparing continuous printing operation starts, in which first of all the developed printing plate 10 is predampened with an extended predampening duration and maximum dampening solution and then the swollen plate layer is pulled off with a reduced setting on the potentiometer Poti and by throwing the ink applicator roll 16 onto the printing plate 10 . Subsequently, the printing emulsion including dampening solution and ink is set. Continuous printing begins after a few revolutions of the plate 10 on the plate cylinder 5 . [0041] In the third variant 3 according to FIG. 6 , first of all predampening is carried out with the maximum application of dampening solution for a relatively long time duration or a relatively high number of machine revolutions, in order to make the nonprinting layer of the plate 10 swell. To this end, the setting of the potentiometer on the dampening unit 14 is 100%. Directly thereafter, the setting of the potentiometer Poti is reduced and the swollen plate layer is pulled off when the ink applicator rolls 16 are thrown on. In contrast to the first variant in FIG. 4 , continuous printing does not then begin, but rather the process is ended after a few revolutions of the plate 10 on the plate cylinder 5 . The plate 10 has then been developed fully and can remain in the machine 1 until the printer desires to activate continuous printing. With the activation of continuous printing, the normal starting program including predampening and subsequent throwing on of the ink applicator roll 16 for setting the printing emulsion including ink and dampening solution is executed, before actual printing begins. [0042] A common feature of the variants 1 to 3 is that the total of plate dampening and predampening takes at least one and one half times as long as in print preparation in the case of printing plates 10 which have already been developed. This ensures that the surface of the printing plate which has not yet been developed can swell sufficiently, as a result of which the nonimaged regions of the printing plate 10 can be removed quickly and cleanly within a few revolutions of the printing press 1 when the ink applicator rolls 16 are thrown on.	A method for developing printing plates in a printing press having at least one printing unit includes loading an imaged, undeveloped printing plate with dampening solution before a start of printing for dampening in at least one printing unit of the printing press for an active duration corresponding at least to one and one half times a time duration or number of machine revolutions provided before a start of printing when an already developed printing plate is used in the same printing press. A printing press for carrying out the method is also provided.	6
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to an electric strike for assembly in a door frame with a pivotal keeper being oriented in position for engagement by a door lock bolt for retaining a door in locked position with the keeper being solenoid controlled and releasably locked in place by a pivotal locking lever and pivotal locking cam with the lever and cam having curved engaging surfaces and the locking cam being operated by movement of a solenoid core with various optional arrangements being provided to enable the strike to satisfy various installational requirements. 2. Description of the Prior Art Electric strikes mounted on door frames and associated with lock bolts on doors are well known with the strikes being provided with a solenoid actuated mechanism in order to selectively release the keeper for pivotal movement so that the door can be released from a remote location by releasing the keeper rather than moving the door lock bolt. U.S. Pat. No. 3,211,850 discloses such an electric strike and the assignee of this application has been actively engaged in the manufacture of electric strikes in accordance with the aforementioned patent for a number of years. U.S. Pat. No. 3,910,617 discloses several embodiments of an electric strike with both patents disclosing arrangements for releasing or actuating the pivotal keeper so that it can selectively retain a door or the like in closed position. While previously known strikes have been used extensively, certain components thereof are subject to wear and, in some instances, the locking components have been disengaged by exerting pressure against the pivotal keeper while impacting or tapping on adjacent surfaces with the vibrations sometimes causing the locking surface to move in relation to each other or "walk" in relation to each other sufficiently to become disengaged thus enabling the keeper to pivot and thus release the door. SUMMARY OF THE INVENTION An object of the present invention is to provide an electric strike adapted to be mounted in various types of door frames, stiles, and the like, for association with a door lock bolt, catch, or the like, in which the strike is provided with a pivotal keeper releasably secured in locked position by a solenoid controlled, pivotally mounted locking lever and locking cam assembly having arcuately curved engaging surfaces. Another object of the invention is to provide an electric strike in which the solenoid for controlling the pivotal keeper is disposed externally of a one-piece cast housing or casing in various orientations to render the strike capable of installation in various space limitations and enabling installation of the strike in door frames or stiles having a standard cut out provided therein. A further object of the invention is to provide an electric strike in accordance with the preceding objects including an insert providing a strain relief for electric wires associated with the strike. Still another object of the present invention is to provide an electric strike having optical fail-safe arrangements. A still further important feature of the present invention is to provide an electric strike in accordance with the preceding objects in which the arcuately curved surfaces generally coincide with the arcuate path of movement of the portion of the locking cam which engages the locking lever, thereby reducing wear of the engaging surfaces with the arcuate surface on the locking lever including an inner end disposed closer to the longitudinal center line of the locking lever as compared with the outer end of the arcuate surface thereby preventing the arcuate surfaces from being disengaged by "walking" movement of the surfaces in relation to each other which sometimes can be accomplished by exerting pressure on the pivotal keeper and thus on the locking lever while tapping or otherwise impacting adjacent surfaces of the door, door frame, and the like. These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part thereof, wherein like numerals refer to like parts throughout. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of the electric strike illustrating the specific structure of the locking lever and locking cam when in their engaged position with the locking lever blocking movement of the pivotal keeper. FIG. 2 is a view similar to FIG. 1 but illustrating the locking cam in the released position and the locking lever disengaged from the pivotal keeper. FIG. 3 is a side elevational view of the electric strike illustrating the reverse side of the strike as compared to FIG. 1 with the strain relief insert illustrated in operative association with the electric wires. FIG. 4 is a fragmental elevational view illustrating an optional association of the blocking cam in which the solenoid, when energized, retains the locking cam in engagement with the locking lever. FIG. 5 is a side elevational view of an embodiment of the invention in which the solenoid is oriented in horizontal position and disengages the locking cam upon energization. FIG. 6 is a side elevational view of the embodiment of the invention illustrated in FIG. 5 illustrating the reverse side thereof as compared with FIG. 5. FIG. 7 is a fragmental elevational view illustrating an optional arrangement in which the locking cam is retained in engaged relation with the locking lever when the solenoid is energized. DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now specifically to FIGS. 1-3, the electric strike of the present invention is generally designated by numeral 10 and which includes a casing 12 of one-piece, cast construction which includes an outer wall 14, an inner wall 16, a bottom wall 18 and a top wall 20 with the front wall 14 including an opening 22 through which projects a pivotal keeper 24 mounted on a vertically extending latch keeper pin 25. An axial keeper spring 26 encircles the pin 25 with one end engaging the casing 12 and the other end engaging the keeper 24 to spring bias the keeper 24 to an outwardly projected position so that it projects through the front wall 14 and a face plate (not shown) attached to the front wall 14 by suitable screw threaded fasteners so that a lock bolt, latch bolt, or the like, on a door will engage the convex surface of the keeper 24 which faces the normally inclined surface on a latch bolt or lock bolt as the door swings to a closed position for operation in the usual manner, so that the lock bolt or latch bolt will engage the generally flat surface 28 of the keeper 24. The keeper 24 is provided with a projection 30 disposed interiorly of the casing 12 and extending to the opposite side of the keeper pin 25 with the projection 30 defining an abutment engaged by or blocked by a locking lever 32 which is pivotally mounted at the upper end portion of the casing 12 by a locking lever pin 34 which is perpendicular to the keeper pin 25 and located above the projection 30 so that the locking lever 32 may pivot to a position out of blocking relationship to the projection 30 as illustrated in FIG. 2, thereby permitting the keeper 24 to pivot about the keeper pin 25 against the resilient bias of the keeper spring 26. This enables the keeper 24 to pivot about the keeper pin 25 when opening force is exerted on the door, thus releasing the lock bolt or latch bolt since the keeper spring 26 will normally keep the keeper in extended position but will enable it to swing to a retracted position when lateral force is exerted on the surface 28. A bushing, such as a brass bushing, or the like, 36 is provided on the locking lever pin 34 to provide for long wearing characteristics and accurate positioning characteristics for the locking lever 32. The projection 30 is generally in the form of a cam surface so that it will tend to pivot the locking lever to an out-of-the-way position against the spring bias of locking lever spring 38 when the lower end of the locking lever is free to swing. To lock the lower end of the locking lever 32 in blocking position in relation to the projection 30 on the keeper 24, a locking cam 40 is pivotally mounted on the lower front portion of the casing 12 by a locking cam pin 42 which is parallel to the locking lever pin 34 and perpendicular to the keeper pin 25. The locking cam 40 includes an upwardly projecting, generally hook-shaped end portion 44 having a concave, arcuately curved inner surface 46 which engages a similarly curved convex arcuate surface 48 on the lower end of the locking lever 32. The upper end edge of the hook-shaped end 44 is generally flat and is received in a notched lower end 50 on the lower end of the locking lever 32 as illustrated in FIGS. 1 and 2. The locking cam 40 is spring biased so that the free hook-shaped end 44 thereof is biased upwardly by an axial coil spring 52 encircling the locking cam pin 42 with one end engaged with the locking cam 40 and the other end engaged with the interior of the casing 12, as illustrated in FIG. 1, thereby spring biasing the locking cam 40 into locking engagement with the locking lever 32 thereby releasably retaining the locking lever in blocking relationship to the projection 30 thereby preventing pivotal movement of the keeper 24 toward a position which would release a lock bolt, latch bolt, or the like. The lower portion of the locking cam 40 is provided with a plate 54 having a roll pin 56 extending therethrough with the roll pin 56 being generally parallel to the locking cam pin 42. The roll pin 56 is received in a horizontally disposed slot 58 formed in the upper end portion of a yoke 60 mounted on the upper end of a reciprocal solenoid core 62 which extends into a threaded mounting sleeve 64 and into a solenoid 66 which is rigidly affixed to the threaded sleeve 64 and is attached to and through the lower end wall 18 of the casing 12 by a screw threaded connection with a lock nut 68 being mounted on the sleeve 64 exteriorly of the casing 12 so that the position of the solenoid can be adjusted by loosening the nut 68 and subsequently tightening it in adjusted position. The roll pin 56 can move in the elongated horizontal slot 58 so that as the core 62 is retracted toward the position illustrated in FIG. 2, the downward force exerted on the roll pin 56 will cause the locking cam 40 to pivot downwardly about locking cam pin 42 to its released position as illustrated in FIG. 2 in which position the roll pin 56 is in the inner, closed end of the slot 58, the other end of the slot being open as illustrated. This structure enables remote energization of the solenoid 66 for disengaging the curved surface 46 on the locking cam 40 from the curved surface 48 on the locking lever 32. This enables the keeper 24 to pivot to a lock bolt releasing position when a force is exerted on the door and door bolt against the keeper 24 with the projecting portion of the keeper 24 pivoting inwardly so that it generally becomes aligned with the front wall 14 or a face plate attached to the front wall 14 of the casing 12. FIG. 4 illustrates a fail-safe arrangement in which the strike enables opening of the door in the event of loss of electrical power. In this embodiment, the locking cam 40' is spring biased to locking engagement with the locking lever 32' since the locking cam 40' is spring biased by a spring 52' which is associated with the locking cam pin 42' and the casing in such a manner to spring bias the outer end of the locking cam 40' downwardly or in a clockwise direction as observed in FIG. 4 thereby releasing the locking cam 40' from the locking lever 32' unless it is retained in the operative position as illustrated in FIG. 4. The bottom edge 70 which is relatively straight on the plate 54' is engaged by the rounded upper end 72 of the solenoid core 62' and as long as the solenoid 66' is energized and the core 62' is extended, it will retain the locking cam 40' in locking engagement with the locking lever 32', but when the solenoid 66' is deenergized for any reason whatsoever, the core 62' will be retracted since it is spring biased inwardly in relation to the solenoid, thus enabling the locking cam 40' to move to a disengaged position. Thus, even if power supply to the solenoid is interrupted inadvertently or due to power failure for any reason whatsoever, the strike will be unlocked so that the keeper can be retracted when opening forces are exerted against a door or the like. FIGS. 5 and 6 illustrate another embodiment of the electric strike in which all of the components are the same as in FIGS. 1-3, except for the locking cam and the solenoid and plunger arrangement. In this embodiment, the locking cam 140 is provided with a plate 154 which has a greater vertical dimension than plate 54 and is generally triangular in shape with the roll pin 156 being adjacent the lower end thereof and the edge of the plate 154 opposite to the locking cam pin 142 is elongated and straight as indicated by numeral 155. The locking cam 140 pivots about the pin 142 and is biased by the spring 152 to an engaged position with the locking lever 132 performing in exactly the same manner as the locking lever 32 in FIGS. 1-3 and the remainder of the structure associated with the keeper, locking lever and casing remain the same. The solenoid 166 is oriented in perpendicular relation to the longitudinal axis of the casing and is attached to the wall 116 in the same manner that the solenoid 66 is attached to the wall 18. The solenoid 166 includes a plunger or core 162 having a rounded end 160 thereon which is engaged with the vertical edge 155 of the cam plate 154 at a point below the pin 142 so that when the core 162 is moved or pushed outwardly of the solenoid 166 when the solenoid is energized, the locking cam 140 will be pivoted downwardly or in a clockwise direction about the pin 142 thus releasing the locking cam 140 from the locking lever 132 in the same manner as the operation of the structure illustrated in FIGS. 1-3. FIG. 7 illustrates a fail-safe embodiment of the invention illustrated in FIGS. 5 and 6 in which all of the structure is identical, except for the plunger 162' having a yoke 160' with a slot or notch 158' therein positioned over and receiving the roll pin 156' with the core 162' being pulled inwardly in relation to the solenoid when energized so that the locking cam 140' will be retained in engagement with the locking lever 132' against the bias of the fail-safe locking cam spring 152' which is associated with the pin 142' in a manner to bias the locking cam 140' to its released, broken line position illustrated in FIG. 7. Thus, if the power supply to the solenoid in the embodiment of FIG. 6 is interrupted for any reason, the electric strike will be released or unlocked by the spring 152' moving the locking cam 140' to a position disengaged from the locking lever 132'. Both embodiments of the invention are provided with a latch bolt monitor switch 74 mounted on a switch mounting plate 76 and an insulating pad 78 with the switch 74 including a finger or actuator 79 engaged by the switch tripper 80 pivotally mounted on the keeper pin 25 and biased to a position out of engagement with the finger 79 by switch tripper spring 82. The signal switch tripper 80 is disposed adjacent the flat surface 28 of the keeper 24 in a position for engagement by the door lock bolt thereby monitoring and indicating at a remote location the position of the position of the door lock bolt. Also, the lower end of the electric strike is provided with a monitoring switch 84 indicating the position of the locking cam 40 with the switch 84 including a finger or actuator 86 extending alongside of the cam plate 54 and in a position for engagement by the roll pin 56, so that as the roll pin is reciprocated between its two extreme positions, it will actuate the switch 84 in order to monitor and indicate at a remote location the specific orientation of the locking cam 40 thereby indicating the condition of the electric strike. Also, both embodiments of the invention include insulated electrical wires 88 connected with the switches 74 and 84 and the solenoid 66 and extending from the upper end of the casing 12. In order to secure the electric wires 88 in relation to the casing 12, an insert 90 of plastic material, such as nylon, is provided in the upper end of the casing immediately below the top wall 20 with the insert 90 gripping the wires 88 in a manner to relieve any strain or force exerted on the electric wires, so that such force will not be exerted on the connections between the wires and the terminals on the switches and solenoids thereby providing for more dependable operation and less chance of inadvertent disconnection of an electric wire from a terminal which can occur when bending or tension forces are exerted on the electric wires, such as when the wires extend directly to the switches and frequently are subjected to bending, twisting, and tension forces during installation and during normal use. The optional orientation of the solenoids illustrated in the embodiment of FIGS. 1-4 and 5-7, respectively, enable the electric strike to be installed in metal jamb door frames or wood jamb door frames, and enable the strike to be installed in standard size cut outs provided in the door frame. The optional fail-safe arrangements illustrated in FIGS. 4 and 7, respectively, enable installation of the strike in orientations where it is necessary or desired for the electric strike to be released upon deenergization of the solenoids either deliberately or by power supply failure. The matching arcuate curvature and the inclination of the surfaces 46 and 48 reduce wear as the curvature of the surfaces generally coincide with the path of movement of the end of the locking cam 40 and the inclination of the surfaces prevents "walking" disengagement of these surfaces by exerting pressure on the keeper and thus on the locking lever while tapping, striking or banging the strike, door, door frame, or adjacent surfaces, thereby providing a dependable and secure electric strike. The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.	An electric strike having a pivotally mounted keeper for engagement by a door lock bolt or the like having a solenoid control, pivotally mounted locking lever and a pivotally mounted locking cam associated with the lever for releasably retaining the lever in blocking relationship to an abutment on the keeper for releasably retaining the keeper in position for engagement by the door lock bolt, thereby enabling the electric strike to be remotely controlled and operated. The locking lever and locking cam are provided with arcuately curved engaging surfaces which precludes the possibility of the locking cam surface being "walked" off of the locking lever by exerting pressure on the keeper while tapping or otherwise impacting the adjacent structure. The curved engaging surfaces of the locking cam and locking lever reduces wear. The solenoid is oriented externally of the casing and can be oriented in different relationships to the casing for installation in various types of doorjambs. Also, the solenoids may be oriented optionally to provide optional failsafe arrangements and the casing is provided with a plastic insert, such as nylon, which serves as a strain relief for the electric wires extending to the solenoid, signal switches, and the like.	4
FIELD OF THE INVENTION The field of art to which this invention pertains is the solid bed adsorptive separation of citric acid from fermentation broths containing citric acid, carbohydrates, amino acids, proteins and salts. More specifically, the invention relates to a process for separating citric acid which process employs an adsorbent comprising particular polymers which selectively adsorb citric acid from a fermentation mixture containing citric acid. BACKGROUND OF THE INVENTION Citric acid is used as a food acidulant, and in pharmaceutical, industrial and detergent formulations. The increased popularity of liquid detergents formulated with citric acid has been primarily responsible for growth of worldwide production of citric acid to about 700 million pounds per year which is expected to continue in the future. Citric acid is produced by a submerged culture fermentation process which employs molasses as feed and the microorganism, Aspergillus Niger. The fermentation product will contain carbohydrates, amino acids, proteins and salts as well as citric acid, which must be separated from the fermentation broth. There are two technologies currently employed for the separation of citric acid. The first involves calcium salt precipitation of citric acid. The resulting calcium citrate is acidified with sulfuric acid. In the second process, citric acid is extracted from the fermentation broth with a mixture of trilaurylamine, n-octanol and a C 10 or C 11 isoparaffin. Citric acid is reextracted from the solvent phase into water with the addition of heat. Both techniques, however, are complex, expensive and they generate a substantial amount of waste for disposal. The patent literature has suggested a possible third method for separating citric acid from the fermentation broth, which involves membrane filtration to remove raw materials or high molecular weight impurities and then adsorption of contaminants onto a nonionic resin based on polystyrene or polyacrylic resins and collection of the citric acid in the rejected phase or raffinate and crystallization of the citric acid after concentrating the solution, or by precipitating the citric acid as the calcium salts then acidifying with H 2 SO 4 , separating the CaSO 4 and contacting cation- and anion-exchangers. This method, disclosed in European Published Application No. 151,470, Aug. 14, 1985, is also a rather complex and lengthy method for separating the citric acid. In contrast, my method makes it possible to separate the citric acid in a single step and to adsorb the citric acid by the adsorbent and obtain the purified citric acid in the desorbent. SUMMARY OF THE INVENTION This invention relates to a process for adsorbing citric acid from a fermentation broth onto a neutral polymeric adsorbent such as nonionogenic, macroreticular, water-insoluble, crosslinked styrenepoly(vinyl)benzene copolymers and copolymers thereof with polymerizable ethylenically unsaturated monomers other than poly(vinyl)benzenes and recovering the citric acid by desorption thereof with a desorbent under desorption conditions. One aspect of the invention is in the discovery that complete separation of citric acid from salts and carbohydrates is only achieved by adjusting and maintaining the pH of the feed solution lower than the first ionization constant (pKa 1 ) of citric acid (3.13). The degree to which the pH must be lowered to maintain adequate selectivity appears to be interdependent on the concentration of citric acid in the feed mixture; the pH is inversely dependent on the concentration. As concentrations are decreased below 13% to very low concentrations, the pH may be near the pKa 1 of citric acid of 3.13; at 13%, the pH may range from 0.9 to 1.7; however, at 40% citric acid feed concentration, the pH must be lowered to at least about 1.2 or lower. At higher concentrations, the pH must be even lower; for example, at 50% citric acid, the pH must be at or below 1.0. Another aspect of the invention is the discovery that the temperature of separation can be reduced by the addition of acetone, or other low molecular weight ketone, to the desorbent; the higher temperatures associated with adsorbent breakdown can thus be avoided. Other aspects of the invention encompass details of feed mixtures, adsorbents, desorbents and operating conditions which are hereinafter disclosed. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plot of concentration of various citric acid species versus the pH of citric acid dissociation which shows the shifting of the equilibrium point of the citric acid dissociation by varying the concentration of citric acid, citrate anions and the hydrogen ion. FIG. 2 is a static plot to determine the effect of pH on amount of citric acid that can be adsorbed by the adsorbent. FIGS. 3A-C are the plots of the pulse tests in Example I using XAD-4 to separate citric acid from a feed containing 13% citric acid at pHs of 2.4, 1.7 and 0.9, respectively. FIGS. 4A-E are plots of the pulse tests of Example II at pHs of 2.4, 1.7, 0.9, 2.8 and 1.4, respectively, run on different adsorbent samples. FIGS. 5A and B are plots of the pulse tests of Example III at pHs of 2.8 and 1.4, respectively, and temperatures of 93°. FIGS. 6A-C are plots of the pulse tests of Example IV at pHs of 1.94, 1.13 and 0.5, respectively. FIGS. 7A-C are plots of the pulse tests of Example V at pHs of 1.82, 0.5 and 0.3, respectively. FIGS. 8A and B are plots of the pulse tests of Example VI at pHs of 1.5 and 1.0, respectively. FIG. 9 is a plot of the pulse test in Example VII showing the adsorption achieved at lower temperatures (93° C. versus 45° C.) through the incorporation of 10% acetone in the desorbent water. DESCRIPTION OF THE INVENTION At the outset the definitions of various terms used throughout the specification will be useful in making clear the operation, objects and advantages of my process. A "feed mixture" is a mixture containing one or more extract components and one or more raffinate components to be separated by my process. The term "feed stream" indicates a stream of a feed mixture which passes to the adsorbent used in the process. An "extract component" is a compound or type of compound that is more selectively adsorbed by the adsorbent while a "raffinate component" is a compound or type of compound that is less selectively adsorbed. In this process, citric acid is an extract component and salts and carbohydrates are raffinate components. The term "desorbent material" shall mean generally a material capable of desorbing an extract component. The term "desorbent stream" or "desorbent input stream" indicates the stream through which desorbent material passes to the adsorbent. The term "raffinate stream" or "raffinate output stream" means a stream through which a raffinate component is removed from the adsorbent. The composition of the raffinate stream can vary from essentially 100% desorbent material to essentially 100% raffinate components. The term "extract stream" or "extract output stream" shall mean a stream through which an extract material which has been desorbed by a desorbent material is removed from the adsorbent. The composition of the extract stream, likewise, can vary from essentially 100% desorbent material to essentially 100% extract components. At least a portion of the extract stream and preferably at least a portion of the raffinate stream from the separation process are passed to separation means, typically fractionators, where at least a portion of desorbent material is separated to produce an extract product and a raffinate product. The terms "extract product" and "raffinate product" mean products produced by the process containing, respectively, an extract component and a raffinate component in higher concentrations than those found in the extract stream and the raffinate stream. Although it is possible by the process of this invention to produce a high purity, citric acid product at high recoveries, it will be appreciated that an extract component is never completely adsorbed by the adsorbent. Likewise, a raffinate component is completely nonadsorbed by the adsorbent. Therefore, varying amounts of a raffinate component can appear in the extract stream and, likewise, varying amounts of an extract component can appear in the raffinate stream. The extract and raffinate streams then are further distinguished from each other and from the feed mixture by the ratio of the concentrations of an extract component and a raffinate component appearing in the particular stream. More specifically, the ratio of the concentration of citric acid to that of the less selectively adsorbed components will be lowest in the raffinate stream, next highest in the feed mixture, and the highest in the extract stream. Likewise, the ratio of the concentration of the less selectively adsorbed components to that of the more selectively adsorbed citric acid will be highest in the raffinate stream, next highest in the feed mixture, and the lowest in the extract stream. The term "selective pore volume" of the adsorbent is defined as the volume of the adsorbent which selectively adsorbs an extract component from the feed mixture. The term "nonselective void volume" of the adsorbent is the volume of the adsorbent which does not selectively retain an extract component from the feed mixture. This volume includes the cavities of the adsorbent which contain no adsorptive sites and the interstitial void spaces between adsorbent particles. The selective pore volume and the nonselective void volume are generally expressed in volumetric quantities and are of importance in determining the proper flow rates of fluid required to be passed into an operational zone for efficient operations to take place for a given quantity of adsorbent. When adsorbent "passes" into an operational zone (hereinafter defined and described) employed in one embodiment of this process its nonselective void volume together with its selective pore volume carries fluid into that zone. The nonselective void volume is utilized in determining the amount of fluid which should pass into the same zone in a countercurrent direction to the adsorbent to displace the fluid present in the nonselective void volume. If the fluid flow rate passing into a zone is smaller than the nonselective void volume rate of adsorbent material passing into that zone, there is a net entrainment of liquid into the zone by the adsorbent. Since this net entrainment is a fluid present in nonselective void volume of the adsorbent, it in most instances comprises less selectively retained feed components. The selective pore volume of an adsorbent can in certain instances adsorb portions of raffinate material from the fluid surrounding the adsorbent since in certain instances there is competition between extract material and raffinate material for adsorptive sites within the selective pore volume. If a large quantity of raffinate material with respect to extract material surrounds the adsorbent, raffinate material can be competitive enough to be adsorbed by the adsorbent. The feed material contemplated in this invention is the fermentation product obtained from the submerged culture fermentation of molasses by the microorganism, Aspergillus Niger. The fermentation product will have a composition exemplified by the following: ______________________________________Citric acid 12.9% ± 3%Salts 6,000 ppmCarbohydrates (sugars) 1%Others (proteins and amino acids) 5%______________________________________ The salts will be K, Na, Ca, Mg and Fe. The carbohydrates are sugars including glucose, xylose, mannose, oligosaccharides of DP2 and DP3 plus as many as 12 or more unidentified saccharides. The composition of the feedstock may vary from that given above and still be used in the invention. However, juices such as citrus fruit juices, are not acceptable or contemplated because other materials contained therein will be adsorbed at the same time rather than citric acid alone. Johson, J. Sci. Food Agric., Vol 33 (3) pp 287-93. I have discovered that the separation of citric acid can be enhanced significantly by adjusting the pH of the feed to a level below the first ionization constant of citric acid. The first ionization constant (pKa 1 ) of citric acid is 3.13, Handbook of Chemistry & Physics, 53rd Edition, 1972-3, CRC Press, and therefore, the pH of the citric acid feed should be below 3.13. When the pH for a 13% concentrated solution of citric acid is 2.4 or greater, for example, as in FIG. 3A (Example I), citric acid "breaks through" (is desorbed) with the salts and carbohydrates at the beginning of the cycle, indicating that all the citric acid is not adsorbed. In contrast, less "break through" of citric acid is observed when the pH is 1.7 and no "break through" when the pH is 0.9 at the 13% level, for example as in Examples 3B and 3C, respectively. I cannot state the reasons for this effect, but, without being bound by my theory, I believe that the following explanation may be correct: The polymeric adsorbents of the invention are nonionic and hydrophobic and, therefore, will selectively adsorb nonionic species compared to ionic species. Thus, I have applied this knowledge to the separation of the nonionic citric acid species from the ionic species. In aqueous solution, unionized citric acid exists in equilibrium with the several citrate anions and hydrogen ions. This is shown in the following equations, where the acid dissociation constants, pKa 1 , pKa 2 and pKa 3 of citric acid at 25° C. are 3.13, 4.74 and 5.40, respectively: ##STR1## The equilibrium point of citric acid dissociation can be shifted by varying the concentrations of citric acid, the citrate anion or the hydrogen ion. This is demonstrated in FIG. 1, for the concentration of the several citric acid species in solution versus pH at 90° C. The result shows a higher percent of nonionized citric acid (H 3 CA) at a higher hydrogen ion concentration (lower pH). Decreasing the pH (raising the H + ion concentration) will introduce more nonionized citric acid while reducing the citrate anionic species (H 2 CA -1 , HCA -2 and CA -3 ) in the solution. Based on the citric acid equilibrium and the resin properties mentioned above, nonionized citric acid will be separated from other ionic species (including citrate anions) in the fermentation broths using the resin adsorbents described. However, for a higher citric acid recovery, a lower pH solution is required. The static adsorption isotherm of a particular resin falling within the invention, Amberlite XAD-4, for citric acid was carried out at room temperature about 25° C., as a function of feed pH. FIG. 2 shows the results of the study. The results show adsorption of the nonionic citric acid as the pH is lowered. This agrees well with my concept mentioned earlier that XAD-4 will selectively adsorb the nonionic species compared to the ionic ones, and that nonionized citric acid is the predominant species at lower pH. Further verification will be presented in the Examples given hereinafter. Desorbent materials used in various prior art adsorptive separation processes vary depending upon such factors as the type of operation employed. In the swing bed system, in which the selectively adsorbed feed component is removed from the adsorbent by a purge stream, desorbent selection is not as critical and desorbent materials comprising gaseous hydrocarbons such as methane, ethane, etc., or other types of gases such as nitrogen or hydrogen may be used at elevated temperatures or reduced pressures or both to effectively purge the adsorbed feed component from the adsorbent. However, in adsorptive separation processes which are generally operated continuously at substantially constant pressures and temperatures to insure liquid phase, the desorbent material must be judiciously selected to satisfy many criteria. First, the desorbent material should displace an extract component from the adsorbent with reasonable mass flow rates without itself being so strongly adsorbed as to unduly prevent an extract component from displacing the desorbent material in a following adsorption cycle. Expressed in terms of the selectivity (hereinafter discussed in more detail), it is preferred that the adsorbent be more selective for all of the extract components with respect to a raffinate component than it is for the desorbent material with respect to a raffinate component. Secondly, desorbent materials must be compatible with the particular adsorbent and the particular feed mixture. More specifically, they must not reduce or destroy the critical selectivity of the adsorbent for an extract component with respect to a raffinate component. Desorbent materials should additionally be substances which are easily separable from the feed mixture that is passed into the process. Both the raffinate stream and the extract stream are removed from the adsorbent in admixture with desorbent material and without a method of separating at least a portion of the desorbent material the purity of the extract product and the raffinate product would not be very high, nor would the desorbent material be available for reuse in the process. It is therefore contemplated that any desorbent material used in this process will preferably have a substantially different average boiling point than that of the feed mixture to allow separation of at least a portion of the desorbent material from feed components in the extract and raffinate streams by simple fractional distillation thereby permitting reuse of desorbent material in the process. The term "substantially different" as used herein shall mean that the difference between the average boiling points between the desorbent material and the feed mixture shall be at least about 5° C. The boiling range of the desorbent material may be higher or lower than that of the feed mixture. Finally, desorbent materials should also be materials which are readily available and therefore reasonable in cost. In the preferred isothermal, isobaric, liquid phase operation of the process of my invention, I have found water a particularly effective desorbent material. Also, for certain reasons, I have found acetone and other low molecular weight ketones, such as methylethyl ketone and diethyl ketone to be effective in admixture with water in small amounts, up to 15%. The key to their usefulness lies in their solubility in water. Their advantage, however, lies in their ability to reduce the temperature at which the desorption can take place. With some adsorbates and water as desorbent, the temperature must be raised to aid the desorption step. Increased temperatures can cause premature deactivation of the adsorbent. A solution to that problem in this particular separation is to add acetone in the amount of 1% to 15% of the desorbent, preferably, 1% to 10% with the most preferred range of 5-10%. The low molecular weight ketone may also affect the adsorbent stability in possibly two ways, by removing solubilizing components which cause deactivation or by effecting regeneration, i.e., by removing the deactivating agent or reversing its effect. I have demonstrated the reduction of the desorption temperature of this separation by approximately 50° C. by adding 10% acetone to the desorbent. A reduction of from about 5° C. to about 70° C. can be achieved by the addition of 1% to 15% acetone to the water desorbent. The prior art has also recognized that certain characteristics of adsorbents are highly desirable, if not absolutely necessary, to the successful operation of a selective adsorption process. Such characteristics are equally important to this process. Among such characteristics are: (1) adsorptive capacity for some volume of an extract component per volume of adsorbent; (2) the selective adsorption of an extract component with respect to a raffinate component and the desorbent material; and (3) sufficiently fast rates of adsorption and desorption of an extract component to and from the adsorbent. Capacity of the adsorbent for adsorbing a specific volume of an extract component is, of course, a necessity; without such capacity the adsorbent is useless for adsorptive separation. Furthermore, the higher the adsorbent's capacity for an extract component the better is the adsorbent. Increased capacity of a particular adsorbent makes it possible to reduce the amount of adsorbent needed to separate an extract component of known concentration contained in a particular charge rate of feed mixture. A reduction in the amount of adsorbent required for a specific adsorptive separation reduces the cost of the separation process. It is important that the good initial capacity of the adsorbent be maintained during actual use in the separation process over some economically desirable life. The second necessary adsorbent characteristic is the ability of the adsorbent to separate components of the feed; or, in other words, that the adsorbent possess adsorptive selectivity, (B), for one component as compared to another component. Relative selectivity can be expressed not only for one feed component as compared to another but can also be expressed between any feed mixture component and the desorbent material. The selectivity, (B), as used throughout this specification is defined as the ratio of the two components of the adsorbed phase over the ratio of the same two components in the unadsorbed phase at equilibrium conditions. Relative selectivity is shown as Equation 1 below: ##EQU1## where C and D are two components of the feed represented in volume percent and the subscripts A and U represent the adsorbed and unadsorbed phases respectively. The equilibrium conditions were determined when the feed passing over a bed of adsorbent did not change composition after contacting the bed of adsorbent. In other words, there was no net transfer of material occurring between the unadsorbed and adsorbed phases. Where selectivity of two components approaches 1.0 there is no preferential adsorption of one component by the adsorbent with respect to the other; they are both adsorbed (or nonadsorbed) to about the same degree with respect to each other. As the (B) becomes less than or greater than 1.0 there is a preferential adsorption by the adsorbent for one component with respect to the other. When comparing the selectivity by the adsorbent of one component C over component D, a (B) larger than 1.0 indicates preferential adsorption of component C within the adsorbent. A (B) less than 1.0 would indicate that component D is preferentially adsorbed leaving an unadsorbed phase richer in component C and an adsorbed phase richer in component D. Ideally desorbent materials should have a selectivity equal to about 1 or slightly less than 1 with respect to all extract components so that all of the extract components can be desorbed as a class with reasonable flow rates of desorbent material and so that extract components can displace desorbent material in a subsequent adsorption step. While separation of an extract component from a raffinate component is theoretically possible when the selectivity of the adsorbent for the extract component with respect to the raffinate component is greater than 1, it is preferred that such selectivity approach a value of 2. Like relative volatility, the higher the selectivity, the easier the separation is to perform. Higher selectivities permit a smaller amount of adsorbent to be used. The third important characteristic is the rate of exchange of the extract component of the feed mixture material or, in other words, the relative rate of desorption of the extract component. This characteristic relates directly to the amount of desorbent material that must be employed in the process to recover the extract component from the adsorbent; faster rates of exchange reduce the amount of desorbent material needed to remove the extract component and therefore permit a reduction in the operating cost of the process. With faster rates of exchange, less desorbent material has to be pumped through the process and separated from the extract stream for reuse in the process. Resolution is a measure of the degree of separation of a two-component system, and can assist in quantifying the effectiveness of a particular combination of adsorbent, desorbent, conditions, etc. for a particular separation. Resolution for purposes of this application is defined as the distance between the two peak centers divided by the average width of the peaks at 1/2 the peak height as determined by the pulse tests described hereinafter. The equation for calculating resolution is thus: ##EQU2## where L 1 and L 2 are the distance, in ml, respectively, from a reference point, e.g., zero to the centers of the peaks and W 1 and W 2 are the widths of the peaks at 1/2 the height of the peaks. A dynamic testing apparatus is employed to test various adsorbents with a particular feed mixture and desorbent material to measure the adsorbent characteristics of adsorptive capacity, selectivity and exchange rate. The apparatus consists of an adsorbent chamber comprising a helical column of approximately 70 cc volume having inlet and outlet portions at opposite ends of the chamber. The chamber is contained within a temperature control means and, in addition, pressure control equipment is used to operate the chamber at a constant predetermined pressure. Quantitative and qualitative analytical equipment such as refractometers, polarimeters and chromatographs can be attached to the outlet line of the chamber and used to detect quantitatively or determine qualitatively one or more components in the effluent stream leaving the adsorbent chamber. A pulse test, performed using this apparatus and the following general procedure, is used to determine selectivities and other data for various adsorbent systems. The adsorbent is filled to equilibrium with a particular desorbent material by passing the desorbent material through the adsorbent chamber. At a convenient time, a pulse of feed containing known concentrations of a tracer and of a particular extract component or of a raffinate component or both, all diluted in desorbent, is injected for a duration of several minutes. Desorbent flow is resumed, and the tracer and the extract component or the raffinate component (or both) are eluted as in a liquid-solid chromatographic operation. The effluent can be analyzed onstream or, alternatively, effluent samples can be collected periodically and later analyzed separately by analytical equipment and traces of the envelopes of corresponding component peaks developed. From information derived from the test adsorbent, performance can be in terms of void volume, retention volume for an extract or a raffinate component, selectivity for one component with respect to the other, and the rate of desorption of an extract component by the desorbent. The retention volume of an extract or a raffinate component may be characterized by the distance between the center of the peak envelope of an extract or a raffinate component and the peak envelope of the tracer component or some other known reference point. It is expressed in terms of the volume in cubic centimeters of desorbent pumped during this time interval represented by the distance between the peak envelopes. Selectivity, (B), for an extract component with respect to a raffinate component may be characterized by the ratio of the distance between the center of the extract component peak envelope and the tracer peak envelope (or other reference point) to the corresponding distance between the center of the raffinate component peak envelope and the tracer peak envelope. The rate of exchange of an extract component with the desorbent can generally be characterized by the width of the peak envelopes at half intensity. The narrower the peak width, the faster the desorption rate. The desorption rate can also be characterized by the distance between the center of the tracer peak envelope and the disappearance of an extract component which has just been desorbed. This distance is again the volume of desorbent pumped during this time interval. To further evaluate promising adsorbent systems and to translate this type of data into a practical separation process requires actual testing of the best system in a continuous countercurrent liquid-solid contacting device. The general operating principles of such a device have been previously described and are found in Broughton U.S. Pat. No. 2,985,589. A specific laboratory size apparatus utilizing these principles is described in deRosset et al., U.S. Pat. No. 3,706,812. The equipment comprises multiple adsorbent beds with a number of access lines attached to distributors within the beds and terminating at a rotary distributing valve. At a given valve position, feed and desorbent are being introduced through two of the lines and the raffinate and extract streams are being withdrawn through two more. All remaining access lines are inactive and when the position of the distributing valve is advanced by one index, all active positions will be advanced by one bed. This simulates a condition in which the adsorbent physically moves in a direction countercurrent to the liquid flow. Additional details on the abovementioned nonionic adsorbent testing apparatus and adsorbent evaluation techniques may be found in the paper "Separation of C 8 Aromatics by Adsorption" by A. J. deRosset, R. W. Neuzil, D. J. Korous, and D. H. Rosback presented at the American Chemical Society, Los Angeles, Calif., Mar. 28 through Apr. 2, 1971. Adsorbents to be used in the process of this invention will comprise nonionogenic, hydrophobic, water-insoluble, crosslinked styrene-poly(vinyl)benzene copolymers and copolymers thereof with monoethylenically unsaturated compounds or polyethylenically unsaturated monomers other than poly(vinyl)benzenes, including the acrylic esters, such as those described in Gustafson U.S. Pat. Nos. 3,531,463 and 3,663,467, both incorporated herein by reference, although not limited thereto. As stated in U.S. Pat. No. 3,531,463, the polymers may be made by techniques disclosed in U.S. Ser. No. 749,526, filed July 18, 1958, now U.S. Pat. Nos. 4,221,871; 4,224,415; 4,256,840; 4,297,220; 4,382,124 and 4,501,826 to Meitzner et al., all of which are incorporated herein by reference. Adsorbents such as just described are manufactured by the Rohm and Haas Company, and sold under the trade name "Amberlite." The types of Amberlite polymers known to be effective for use by this invention are referred to in Rohm and Haas Company literature as Amberlite adsorbents XAD-1, XAD-2, XAD-4, XAD-7 and XAD-8, and described in the literature as "hard, insoluble spheres of high surface, porous polymer." The various types of Amberlite polymeric adsorbents differ somewhat in physical properties such as porosity volume percent, skeletal density and nominal mesh sizes, but more so in surface area, average pore diameter and dipole moment. The preferred adsorbents will have a surface area of 10-2000 square meters per gram and preferably from 100-1000 m 2 /g. These properties are listed in the following table: TABLE 1__________________________________________________________________________Properties of Amberlite Polymeric Adsorbents XAD-7 XAD-8 XAD-1 XAD-2 XAD-4 Acrylic AcrylicChemical Nature Polystyrene Polystyrene Polystyrene Ester Ester__________________________________________________________________________Porosity 37 42 51 55 52Volume %True Wet Density 1.02 1.02 1.02 1.05 1.09grams/ccSurface Area 100 300 780 450 160M.sup.2 /gramAverage Pore Diameter 200 90 50 90 225AngstromsSkeletal Density 1.07 1.07 1.08 1.24 1.23grams/ccNominal Mesh Size 20-50 20-50 20-50 20-50 25-50Dipole Moment of 0.3 0.3 0.3 1.8 1.8Functional Groups__________________________________________________________________________ Applications for Amberlite polymeric adsorbents suggested in the Rohm and Haas Company literature include decolorizing pulp mill bleaching effluent, decolorizing dye wastes and removing pesticides from waste effluent. There is, of course, no hint in the literature of my surprising discovery of the effectiveness of Amberlite polymeric adsorbents in the separation of citric acid from Aspergillus-Niger fermentation broths. The adsorbent may be employed in the form of a dense compact fixed bed which is alternatively contacted with the feed mixture and desorbent materials. In the simplest embodiment of the invention the adsorbent is employed in the form of a single static bed in which case the process is only semicontinuous. In another embodiment a set of two or more static beds may be employed in fixed bed contacting with appropriate valving so that the feed mixture is passed through one or more adsorbent beds while the desorbent materials can be passed through one or more of the other beds in the set. The flow of feed mixture and desorbent materials may be either up or down through the desorbent. Any of the conventional apparatus employed in static bed fluid-solid contacting may be used. Countercurrent moving bed or simulated moving bed countercurrent flow systems, however, have a much greater separation efficiency than fixed adsorbent bed systems and are therefore preferred. In the moving bed or simulated moving bed processes the adsorption and desorption operations are continuously taking place which allows both continuous production of an extract and a raffinate stream and the continual use of feed and desorbent streams. One preferred embodiment of this process utilizes what is known in the art as the simulated moving bed countercurrent flow system. The operating principles and sequence of such a flow system are described in U.S. Pat. No. 2,985,589 incorporated herein by reference thereto. In such a system it is the progressive movement of multiple liquid access points down an adsorbent chamber that simulates the upward movement of adsorbent contained in the chamber. Only four of the access lines are active at any one time; the feed input stream, desorbent inlet stream, raffinate outlet stream, and extract outlet stream access lines. Coincident with this simulated upward movement of the solid adsorbent is the movement of the liquid occupying the void volume of the packed bed of adsorbent. So that countercurrent contact is maintained, a liquid flow down the adsorbent chamber may be provided by a pump. As an active liquid access point moves through a cycle, that is, from the top of the chamber to the bottom, the chamber circulation pump moves through different zones which require different flow rates. A programmed flow controller may be provided to set and regulate these flow rates. The active liquid access points effectively divided the adsorbent chamber into separate zones, each of which has a different function. In this embodiment of my process it is generally necessary that three separate operational zones be present in order for the process to take place although in some instances an optional fourth zone may be used. The adsorption zone, zone 1, is defined as the adsorbent located between the feed inlet stream and the raffinate outlet stream. In this zone, the feedstock contacts the adsorbent, extract component is adsorbed, and a raffinate stream is withdrawn. Since the general flow through zone 1 is from the feed stream which passes into the zone to the raffinate stream which passes out of the zone, the flow in this zone is considered to be a downstream direction when proceeding from the feed inlet to the raffinate outlet streams. Immediately upstream with respect to fluid flow in zone 1 is the purification zone, zone 2. The purification zone is defined as the adsorbent between the extract outlet stream and the feed inlet stream. The basic operations taking place in zone 2 are the displacement from the nonselective void volume of the adsorbent of any raffinate material carried into zone 2 by shifting of adsorbent into this zone and the desorption of any raffinate material adsorbed within the selective pore volume of the adsorbent or adsorbed on the surfaces of the adsorbent particles. Purification is achieved by passing a portion of extract stream material leaving zone 3 into zone 2 at zone 2's upstream boundary, the extract outlet stream, to effect the displacement of raffinate material. The flow of material in zone 2 is in a downstream direction from the extract outlet stream to the feed inlet stream. Immediately upstream of zone 2 with respect to the fluid flowing in zone 2 is the desorption zone or zone 3. The desorption zone is defined as the adsorbent between the desorbent inlet and the extract outlet stream. The function of the desorption zone is to allow a desorbent material which passes into this zone to displace the extract component which was adsorbed upon the adsorbent during a previous contact with feed in zone 1 in a prior cycle of operation. The flow of fluid in zone 3 is essentially in the same direction as that of zones 1 and 2. In some instances an optional buffer zone, zone 4, may be utilized. This zone, defined as the adsorbent between the raffinate outlet stream and the desorbent inlet stream, if used, is located immediately upstream with respect to the fluid flow to zone 3. Zone 4 would be utilized to conserve the amount of desorbent utilized in the desorption step since a portion of the raffinate stream which is removed from zone 1 can be passed into zone 4 to displace desorbent material present in that zone out of that zone into the desorption zone. Zone 4 will contain enough adsorbent so that raffinate material present in the raffinate stream passing out of zone 1 and into zone 4 can be prevented from passing into zone 3 thereby contaminating extract stream removed from zone 3. In the instances which the fourth operational zone is not utilized the raffinate stream passed from zone 1 to zone 4 must be carefully monitored in order that the flow directly from zone 1 to zone 3 can be stopped when there is an appreciable quantity of raffinate material present in the raffinate stream passing from zone 1 into zone 3 so that the extract outlet stream is not contaminated. A cyclic advancement of the input and output streams through the fixed bed of adsorbent can be accomplished by utilizing a manifold system in which the valves in the manifold are operated in a sequential manner to effect the shifting of the input and output streams thereby allowing a flow of fluid with respect to solid adsorbent in a countercurrent manner. Another mode of operation which can effect the countercurrent flow of solid adsorbent with respect to fluid involves the use of a rotating disc valve in which the input and output streams are connected to the valve and the lines through which feed input, extract output, desorbent input and raffinate output streams pass are advanced in the same direction through the adsorbent bed. Both the manifold arrangement and disc valve are known in the art. Specifically rotary disc valves which can be utilized in this operation can be found in U.S. Pat. Nos. 3,040,777 and 3,422,848. Both of the aforementioned patents disclose a rotary type connection valve in which the suitable advancement of the various input and output streams from fixed sources can be achieved without difficulty. In many instances, one operational zone will contain a much larger quantity of adsorbent than some other operational zone. For instance, in some operations the buffer zone can contain a minor amount of adsorbent as compared to the adsorbent required for the adsorption and purification zones. It can also be seen that in instances in which desorbent is used which can easily desorb extract material from the adsorbent that a relatively small amount of adsorbent will be needed in a desorption zone as compared to the adsorbent needed in the buffer zone or adsorption zone or purification zone or all of them. Since it is not required that the adsorbent be located in a single column, the use of multiple chambers or a series of columns is within the scope of the invention. It is not necessary that all of the input or output streams be simultaneously used, and in fact, in many instances one of the streams can be shut off while others effect an input or output of material. The apparatus which can be utilized to effect the process of this invention can also contain a series of individual beds connected by connecting conduits upon which are placed input or output taps to which the various input or output streams can be attached and alternately and periodically shifted to effect continuous operation. In some instances, the connecting conduits can be connected to transfer taps which during the normal operations do not function as a conduit through which material passes into or out of the process. It is contemplated that at least a portion of the extract output stream will pass into a separation means wherein at least a portion of the desorbent material can be separated to produce an extract product containing a reduced concentration of desorbent material. Preferably, but not necessary to the operation of the process, at least a portion of the raffinate output stream will also be passed to a separation means wherein at least a portion of the desorbent material can be separated to produce a desorbent stream which can be reused in the process and a raffinate product containing a reduced concentration of desorbent material. The separation means will typically be a fractionation column, the design and operation of which is well-known to the separation art. Reference can be made to D. B. Broughton U.S. Pat. No. 2,985,589, and to a paper entitled "Continuous Adsorptive Processing--A New Separation Technique" by D. B. Broughton presented at the 34th Annual Meeting of the Society of Chemical Engineers at Tokyo, Japan on Apr. 2, 1969, both incorporated herein by reference, for further explanation of the simulated moving bed countercurrent process flow scheme. Although both liquid and vapor phase operations can be used in many adsorptive separation processes, liquid-phase operation is preferred for this purpose because of the lower temperature requirements and because of the higher yields of extract product than can be obtained with liquid-phase operation over those obtained with vapor-phase operation. Absorption conditions will include a temperature range of from about 20° C. to about 200° C. with about 65° C. to about 100° C. being more preferred and a pressure range of from about atmospheric to about 500 psig (3450 kPa gauge) being more preferred to ensure liquid phase. Desorption conditions will include the same range of temperatures and pressures as used for adsorption conditions. The size of the units which can utilize the process of this invention can vary anywhere from those of pilot plant scale (see for example our assignee's U.S. Pat. No. 3,706,812, incorporated herein by reference) to those of commerical scale and can range in flow rates from as little as a few cc an hour up to many thousands of gallons per hour. The following examples are presented to illustrate the selectivity relationship that makes the process of my invention possible. The example is not intended to unduly restrict the scope and spirit of claims attached hereto. EXAMPLE I In this example, three pulse tests were run with a neutral styrene divinylbenzene polymeric adsorbent (XAD-4 made by Rohm & Haas Company) to determine the ability of the adsorbent to separate citric acid, at different pHs, from its fermentation mixture of carbohydrates (DP1, DP2, DP3, including glucose, xylose, arabinose and raffinose) and ions of salts, including Na + , K + , Mg ++ , Ca ++ , Fe +++ , Cl - , SO 4 = , PO 4 .sup.═ and NO 3 - , amino acids and proteins. The first test was run at a pH of 2.4 and 45° C. Two further tests were run at a pH of 1.7 and 0.9. Citric acid was desorbed with water. The fermentation feed mixture had the following composition: ______________________________________Feed Composition Amount______________________________________Citric Acid 12.9%Salts (K.sup.+, Na.sup.+, Ca.sup.++, Mg.sup.++ Fe.sup.+++) 0.60% (6000 ppm)Carbohydrates (Sugars) 1%Others (SO.sub.4.sup.=, Cl.sup.-, PO.sub.4.sup.≡, 5%.sub.3.sup.-,proteins and amino acids)Water 81.5%______________________________________ Retention volumes and resolution were obtained using the pulse test apparatus and procedure previously described. Specifically, the adsorbent was tested in a 70 cc straight column using the following sequence of operations for the pulse test. Desorbent material was continuously run upwardly through the column containing the adsorbent at a nominal liquid hourly space velocity (LHSV) of about 1.0. A void volume was determined by observing the volume of desorbent required to fill the packed dry column. At a convenient time the flow of desorbent material was stopped, and a 10 cc sample of feed mixture was injected into the column via a sample loop and the flow of desorbent material was resumed. Samples of the effluent were automatically collected in an automatic sample collector and later analyzed for salts and citric acid by chromatographic analysis. Some later samples were also analyzed for carbohydrates, but since they were eluted at approximately the same rate as the carbohydrates, they were not analyzed in these examples nor were other minor ingredients, amino acids and proteins. From the analysis of these samples, peak envelope concentrations were developed for the feed mixture components. The retention volume for the citric acid was calculated by measuring the distance from the midpoint of the net retention volume of the salt envelope as the reference point to the midpoint of the citric acid envelope. The resolution, R, is calculated from Equation 2, given earlier. The results for these pulse tests are shown in the following table. TABLE 2______________________________________ Net retention Peak Width ResolutionComponent Volume at 0.5 Height (0.5 Height)______________________________________Test A - pH - 2.4Salts 0 14.4 1.39Citric acid 44.4 49.5 ReferenceTest B - pH - 1.7Salts 0 11.6 1.49Citric acid 42.2 45.1 ReferenceTest C - pH - 0.9Salts 0 13.3 1.4Citric acid 40.9 45.1 Reference______________________________________ The results are also shown in FIG. 3A in which it is clear that while citric acid is more strongly adsorbed than the other components, there is a substantial loss of citric acid which is unadsorbed and removed with the salts and carbohydrates (not shown). Citric acid is satisfactorily separated in the process in FIG. 3B where the results are judged good and in FIG. 3C where the results were judged excellent. The process clearly will have commercial feasibility at a pH of 1.7 and lower. At a pH of 2.4 (FIG. 3A), however, it is noted that a substantial amount of the citric acid will be recovered, I theorize, as the citrate, H 2 CA -1 , in the raffinate with the salts and carbohydrates. From this, I conclude that the ionized, soluble species should be reduced, as explained previously, by maintaining a lower pH in the feed, thereby driving the equilibrium in Equation 1 to the left. EXAMPLE II This example presents the results of using a neutral crosslinked styrene divinylbenzene (XAD-4) and a neutral crosslinked polyacrylic ester copolymer (XAD-8) with the same separation feed mixture as Example I at different pHs to demonstrate the poor separation when the pH is 2.4 or higher, or above the first ionization constant, pKa 1 =3.13, of citric acid. The same procedure and apparatus previously described in Example I were used in the separation, except the temperature was 60° C. and 5 ml of feed mixture was used. FIGS. 4A, 4B and 4C are, respectively, graphical presentations of the results of the pulse tests using XAD-4 at pHs, respectively, of 2.4, 1.7 and 0.9. FIG. 4A shows that citric acid "breaks through" with the salts (and carbohydrates). This problem can be partially alleviated by lowering the pH to 1.7 as in FIG. 4B. An excellent separation can be achieved by lowering the pH further to 0.9 as in FIG. 4C. This separation, with adjustments of the pH, again, clearly has commercial utility. FIGS. 4D and 4E are, respectively, graphical representations of the results of pulse tests, run under the same conditions as above, using XAD-8 at pHs of 2.8 and 1.4 and temperatures of 65° C. FIG. 4D, which was made at a pH of 2.8, shows no separation, but rather the salts, carbohydrates and citric acid eluting together initially. After about 67 ml, after most of the carbohydrates and salts and some of the citric acid have been recovered, some relatively pure citric acid can be obtained, but recovery is low. FIG. 4E, which was made at a pH of 1.4, shows a selectivity between citric acid and carbohydrates and salts which results in a satisfactory separation and recovery of the citric acid. EXAMPLE III This example presents the results of using a neutral crosslinked styrene divinylbenzene copolymer (XAD-4) with the same separation feed mixture as Example I at two different pHs to demonstrate the poor separation when the pH is 2.4 or higher. The same procedure and apparatus previously described in Example I were used, except the temperature was 93° C. in FIGS. 5A and 5B and the amount of feed mixture was 10 ml. FIGS. 5A and 5B are, respectively, graphical presentations of the results of pulse tests using XAD-4 at pHs, respectively, of 2.8 and 1.4. FIG. 5A shows that citric acid "breaks through" with the salts and carbohydrates. This problem can be alleviated by lowering the pH to 1.4 as in FIG. 5B. This separation, with adjustment of the pH, again, clearly has commercial utility. EXAMPLE IV The procedure and apparatus previously described in Example I was used on the samples of this example. The temperature was 60° C. and 5 ml of feed mixture was used. The feed composition was similar to that previously used except that citric acid has been concentrated to 40% in the feed mixture. The effect of concentration on the pH will be seen. In FIG. 6A, even with the temperature at 60° C., the pH of 1.9 is too high to separate the citric acid at 40% concentration. By adjusting the pH downward as in FIGS. 6B and 6C, the citric acid is preferentially adsorbed and excellent separation is achieved at a pH of 0.5. In each of these samples, carbohydrates were not analyzed, but it can be assumed that the carbohydrates closely followed the salts in the separation. EXAMPLE V The procedure and apparatus previously described in Example I was used on the three samples of this example. The temperature was 93° C. and the amount of feed mixture was 5 ml. The feed composition was similar to that previously used except that citric acid has been concentrated to 40% in the feed mixture to demonstrate the further effect of concentration on the pH. In FIG. 7A, even with the temperature at 93° C., the pH of 1.8 is too high to separate the citric acid at 40% concentration. By adjusting the pH downward as in FIGS. 7B and 7C, the citric acid is preferentially adsorbed and excellent separation is achieved. Again, carbohydrates were not analyzed, but it can be assumed that the carbohydrates closely followed the salts in the separation. EXAMPLE VI The pulse test of Example I was repeated on two 50% citric acid samples using XAD-4 adsorbent. The desorbent in both cases was water. The composition of the feed used was the same as used in Example I except that citric acid has been concentrated to 50%. The temperature was 93° C. In the first sample, the pH was 1.5. As shown in FIG. 8A, citric acid was not separated. After reducing the pH to 1.0 in the second sample, citric acid was readily separated as seen in FIG. 8B. Again, carbohydrates were not analyzed, but assumed to closely follow the salts. The separation in FIG. 8B was judged good. EXAMPLE VII The separation example represented by FIGS. 7B and 7C required high temperatures, e.g., 93° C. to achieve the separation of 40% citric acid due to the difficulty in desorbing citric acid from the XAD-4 adsorbent. In this example, high temperatures, which adversely affect the adsorbent life and the cost to operate, are eliminated and the separation is readily achieved at 45° C. through the use of a desorbent mixture of 10% (by wt.) acetone and 90% water. Referring to FIG. 9, a feed comprising 40% (wt.) citric acid, 4% carbohydrates and 2% salts of the following elements: K + , Na + , Mg ++ , Fe +++ , Ca ++ plus proteins and amino acids, was introduced into the pulse test apparatus as set forth previously and the test ran as before except that the temperature was 45° C. In this test, the pH was maintained at 0.5, but the desorbent contained acetone as mentioned above. The net retention volume for citric acid was 10.7 ml, and the resolution was 0.61 and, therefore, the separation was easily made.	Citric acid is separated from a fermentation broth by using an adsorbent comprising a neutral, noniogenic, macroreticular, water-insoluble, crosslinked styrene-poly(vinyl)benzene and a desorbent comprising water and, optionally, acetone with the water. The pH of the feed is adjusted and maintained below the first ionization constant (pKa 1 ) of citric acid to maintain selectivity.	2
CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. patent application 60/888,069, filed on Feb. 2, 2007, which is incorporated herein by reference. FIELD OF THE INVENTION The invention relates to attachments for power assisted lifting devices capable of rigidly positioning an object in three-dimensional space, for example pneumatically assisted manually operated mechanical arm manipulators, wherein the attachment is capable of securing an object for remote positioning thereof. More particularly, the invention relates to an end effector for a pneumatic manipulator that is capable of both passively following the motion of a secured object and actively adjusting the position of the secured object in an arcuate direction relative to the attachment of the end effector to the manipulator. The end effector is particularly useful in the bending of metallic sheets or plates using a conventional sheet metal brake, as the end effector is capable of both positioning heavy sheets in the brake and following the movement of the sheet as it is being bent. Also disclosed are pneumatic manipulators including the end effector and methods of bending plates using the end effector. BACKGROUND Certain types of lifting devices are capable of both lifting heavy objects and rigidly positioning objects in three-dimensional space. For example, pneumatically assisted manually operated manipulators have found widespread use. These manipulators typically consist of an arm that extends outwardly in a generally horizontal direction from a mast about which it is permitted to rotate and from which it is also permitted to pivot arcuately in a generally vertical direction in a pneumatically assisted manner. The arm may include one or more extension members serially disposed from an end of the arm distal from the mast that are similarly permitted to rotate and/or pivot. This arrangement permits the positioning of the distal end of the arm or extension member at a desired location in three dimensional space. An end effector is an attachment coupled to the distal end of the arm or extension member and adapted for the manipulation of a desired object or for the conduct of a particular task. For example, an end effector may include clamping means, pincer means, magnetic means or the like that are shaped and/or sized for the securement of a desired object to be positioned. The manipulator normally includes a pneumatic cylinder adjusted to a pre-determined pressure selected so that the weight of the object is just balanced by the cylinder. In this manner, the object becomes weightless with respect to the operator, who is then able to manually position the object in three dimensional space. When bending a sheet of steel using a conventional sheet metal brake, a portion of the sheet is placed within the brake and another portion of the sheet extends outwardly therefrom. The brake includes a hydraulically operated edge that fits within a complementary die located on the press. When the edge is engaged with the sheet to effect the bend, the outwardly extending portion of the sheet moves arcuately in response to bending of the sheet within the die. Conventionally, human operators hold the sheet during the bending operation and are required to follow the arcuate movement of the sheet with their arms, often ending with the operator's arms in an overhead position. This repetitive arm movement can lead to occupational strain injuries that are particularly exacerbated when heavy sheets are being bent. There is also a risk of limb loss or other accidental injury due to the proximity of the operators to the press and the potential for the operators to drop the sheet. Although it would be desirable to utilize a pneumatically assisted manually operated manipulator in this application, currently no end effector exists that is capable of both positioning the sheet within the brake and following the arcuate movement of the sheet during the bending operation. Conventional passive end effectors are not capable of rotating or otherwise actively re-positioning the angular orientation of the sheet in order to permit successive bending operations to take place on the same sheet. What is needed is an end effector for a manipulator that is capable of both passively following the movement of the sheet and actively re-positioning the sheet. It would be desirable is this end effector were provided in combination with a suitable manipulator for working with heavy sheets. Although conventional manipulators make the object being lifted essentially weightless, the manipulator itself requires a certain amount of human power to adjust its position. In order to manipulate heavy objects, the size of the manipulator increases as well as the size of the pneumatic cylinders. Operators are required to overcome both the inertia of the manipulator and to aid in the expression of air from the cylinders during re-positioning of the object. It would therefore be desirable to have a power assisted lifting feature on manipulators to selectively reduce the amount of manual effort required by the operator during re-positioning operations. It would be further desirable to include this power assisted lifting feature in conjunction with end effectors suitable for sheet bending operations. SUMMARY OF THE INVENTION According to the present invention, there is provided an attachment for a lifting device capable of positioning an object in three-dimensional space, the attachment comprising: a selectively engageable securement means for selectively securing the object to the attachment and selectively releasing the object from the attachment; a pivot for permitting arcuate movement of the attachment relative to the lifting device; a resilient biasing means for providing a biasing force sufficient to offset the weight of the object, the biasing means permitting externally induced movement of the attachment means about the pivot; and, an adjustment means for selectively providing an adjustment force for changing an angular orientation of the attachment relative to the pivot. According to another aspect of the present invention, there is provided a pneumatically assisted manually operated manipulator comprising: a rotatable vertical extension member manually positionable in three-dimensional space; an end-effector attached to the vertical extension member comprising, a selectively engageable securement means for selectively securing the object to the attachment and selectively releasing the object from the attachment, a pivot for permitting arcuate movement of the attachment relative to the lifting device, a resilient biasing means for providing a biasing force sufficient to offset the weight of the object, the biasing means permitting externally induced movement of the attachment means about the pivot, and, an adjustment means for selectively providing an adjustment force for changing an angular orientation of the attachment relative to the pivot; an operator control center on the vertical extension member operatively interconnected with the end effector; and, at least a handle for use by an operator in manually positioning the end-effector. According to yet another aspect of the present invention, there is provided a method of bending an object comprising a sheet of material using a press, the method comprising: providing a lifting device capable of manually positioning the object in three-dimensional space; providing an attachment on the lifting device having securement means for securing the object, the attachment able to passively move in response to externally induced movement of the object and able to actively change the angular orientation of the object; manually positioning the attachment adjacent the object and securing the object with the securement means; manually positioning the object within the press using the lifting device; bending the object using the press, thereby creating externally induced movement of the object; allowing the attachment to passively move in response to the externally induced movement; manually removing the object from the press using the lifting device; and, actively changing the angular orientation of the object using the attachment. BRIEF DESCRIPTION OF THE DRAWINGS Having summarized the invention, preferred embodiments thereof will now be described with reference to the accompanying figures, in which: FIG. 1 a shows a manipulator according to an embodiment of the present invention with a sheet of steel being bent into a first position by a sheet metal press; FIG. 1 b shows the manipulator of FIG. 1 a with the sheet of steel being bent into a second position; FIG. 2 a shows an attachment of the manipulator of FIG. 1 a in side view with a sheet of steel in the first position; FIG. 2 b shows the attachment of FIG. 2 a in side view with a sheet of steel in the second position; FIG. 2 c shows the attachment of FIG. 2 a in end view with a sheet of steel in the second position; FIG. 3 a shows the attachment of FIG. 2 a in perspective view along with a portion of an embodiment of a manipulator having a sliding shuttle; FIG. 3 b shows the attachment of FIG. 2 b in perspective view along with a portion of the embodiment of a manipulator depicted in FIG. 3 a; FIG. 4 a shows the manipulator of FIG. 1 a in side view bending the sheet of steel into the first position; FIG. 4 b is an enlarged side view of the attachment depicted in FIG. 4 a; FIG. 4 c shows the manipulator of FIG. 1 b in side view bending the sheet of steel into the second position; and, FIG. 4 d is an enlarged side view of the attachment depicted in FIG. 4 c. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIG. 1 a , a pneumatically assisted manually operated manipulator, generally denoted as 1 , comprises a vertical mast 2 with an arm 3 extending outwardly therefrom. The arm 3 is rotatably attached to the mast 2 by a first rotation means 4 that permits rotation of the arm about a first vertical axis 5 passing through the mast 2 . The proximal end of the arm 3 is mounted to the first rotation means 4 by way of a pivot assembly 6 that permits the arm 3 to arcuately move as well as rotate. A second rotation means 7 is provided at the distal end of the arm 3 and is mounted in a manner that permits a second rotation axis 8 to remain vertical at all times, irrespective of the angular orientation of the arm 3 . In the embodiment shown, the vertical orientation of the rotation means 7 is maintained using a parallelogram linkage 9 , although other means, for example trunnion mounts or gimbals, could also be used. One end of a horizontal extension member 10 is attached to the second rotation means 7 at the distal end of the arm 3 . The opposite end of the horizontal extension member 10 includes a third rotation means 11 to which is mounted a vertical extension member 12 . The length of both the horizontal and vertical extension members 10 , 12 is chosen based on the intended application of the manipulator 1 . Additional extension members, either horizontal or vertical, may be added depending on the range and degree of motion required for a particular application. A pneumatic lift cylinder (not shown) connects the arm 3 to the mast 2 via a linkage located near the proximal end of the arm and is operable to resiliently bias the arm against the weight of an object being carried by the manipulator. In operation, the pneumatic lift cylinder normally has at least two operating pressures: a first (lower) pressure chosen to offset the weight of the arm and extension members so that the position of the manipulator may be manually adjusted; and, a second (higher) pressure chosen to offset the weight of the object as well as the arm and extension members. Switching from the first to the second pressures occurs when an operator attempts to manually lift the object with the manipulator and switching from the second to the first pressure occurs when the object is released. In this manner, the manipulator appears to the operator to remain neutrally buoyant, irrespective of whether or not an object is being carried. The pneumatically assisted manually operated manipulator shown here is but one embodiment of such a device. Persons skilled in the art will realize that variations on such manipulators may also be used in the same way to achieve the same function. In fact, any lifting device that permits an object to be positioned at a selected location in three-dimensional space may be used. For example, an overhead gantry crane comprising an extendable downwardly depending mast may be used in place of the embodiment of a manipulator pictured herein to similar effect. However, it is preferable that the lifting device or manipulator permits passive or externally induced movement in at least the vertical direction, for example in response to the bending of a sheet of steel 13 . An attachment 14 is provided on the vertical extension member 12 . The attachment 14 , also known as an end-effector, is permitted to arcuately move in the vertical direction in response to bending of the sheet of steel 13 . This externally induced bending movement also causes the vertical extension member 12 to move downwardly. The attachment 14 will be described in greater detail hereinafter. A sheet metal brake or press 15 comprises a movable edge (not shown) that fits within a complementary die 16 . The angle of the die is selected so as to create the desired bend. In FIG. 1 a , it can be seen that the sheet 13 has an outwardly extending tab 17 on the left side of the sheet as viewed by the operator 18 and the bend passes through this tab. Often, a single sheet of steel 13 requires multiple bends that may need to occur in one or both sides of the sheet to achieve the desired shape. It is therefore advantageous not only to follow the externally induced movement of a sheet as it is being bent, but also to remove the sheet after a particular bend has been made and re-position and/or flip the sheet for the next required bend. Referring to FIG. 1 b , it can be seen that, in order to achieve the desired shape, it was necessary to flip the sheet, as evidenced by the location of the tab 17 on the right side of the sheet as viewed by the operator 18 . After flipping, the sheet 13 was repositioned in the press 15 so that the next bend was in the desired location. This re-positioning necessitated both the partial withdrawal of the sheet from the press 15 and the creation of a different angular orientation of the attachment 14 relative to the vertical extension 12 . The creation of a different angular orientation is effected by an active re-positioning of the attachment 14 that will be described in greater detail hereinafter. Referring to FIGS. 2 a , 2 b and 2 c , the attachment 14 is pivotally attached to the vertical extension member 12 by a pivot 19 . The pivot 19 permits the attachment 14 to move arcuately in response to externally induced bending movement of the sheet 13 , as can be seen by comparing FIGS. 2 a and 2 b . A pneumatic tilt cylinder 20 is provided on the vertical extension member 12 and pivotally attached to a rearwardly extending lever portion 21 of the attachment 14 anterior of the pivot 19 . The pneumatic tilt cylinder 20 functions in a manner similar to the previously described pneumatic lift cylinder, with first and second pressures selected to offset the moment created by the weight of the attachment means by itself and the attachment means plus the object (sheet 13 ), respectively. Those skilled in the art will recognize that, since the required cylinder pressure depends on the moment exerted on the pivot 19 by the tilting of an object, and since the moment is a function of both the weight of the object and the length of the object relative to the attachment 14 , therefore more than one second pressure set point may be required for lifting the same object from different locations on the object. The pneumatic tilt cylinder 20 may be operated using any number of pre-determined pressure set points in order to allow the lifting of a variety of objects and/or to allow lifting from a variety of positions on the same object. Alternatively, the second pressure set point may be operator adjustable in order to provide maximum flexibility in lifting location. During the passive mode of operation, the pneumatic tilt cylinder 20 plus the lever portion 21 function as a resilient biasing means that permits arcuate movement of the attachment means in response to externally induced bending movement of the sheet 13 . After the bending operation is completed and the sheet 13 is removed from the press 14 using the manipulator, the angular position of the sheet may have to be actively adjusted in order that the sheet enters the press at an appropriate angle. This is accomplished by injecting air into or exhausting air from the pneumatic tilt cylinder 20 in order that the second pressure is slightly elevated or slightly reduced, respectively, relative to its setpoint. This has the effect of upwardly or downwardly arcuately moving the attachment means about pivot 19 . However, since a regulator is employed to constantly maintain the second pressure, this active tilting operation is continuously resisted by the regulator as it tries to maintain the second pressure setpoint. The active tilting operation is activated using switches on the operator control center 22 and, when the switches are released, the regulator returns the pressure in the tilt cylinder 20 to the second pressure set point and the arcuate movement of the attachment 14 stops. Since only a slight increase or decrease in the cylinder pressure occurs, the active mode of operation is quite safe and any inadvertent impact between the object 13 and an obstacle immediately halts the arcuate movement without risk of injury or property damage. In the active mode, the pneumatic tilt cylinder 20 and the lever 21 together function as an adjustment means for selectively provided the force required to change the angular orientation of the sheet 13 . Although the biasing means and the adjustment means share common components of the attachment 14 , they utilize those components at different times during different modes of operation and therefore tend to function in a mutually exclusive manner. The attachment 14 is also provided with securement means 24 for securing the sheet 13 to the attachment. In the embodiment shown, the securement means 24 comprises a pair of pneumatically actuated clamps; however, it will be evident to persons skilled in the art that the securement means may comprise any suitable selectively actuated gripping element, for example a pincer, an electro-magnet, a vacuum powered suction cup, or the like. The securement means 24 is selectively actuated using the operator controls 22 . The gripping force is normally pre-determined based upon the characteristics of the object being lifted, but also may be user adjustable to suit the gripping of different objects. Since it is often necessary to flip the sheet 13 to achieve the desired shape, the attachment 14 preferably further includes a rotation means 25 . The rotation means 25 is mounted on a shaft 26 extending from the pivot 19 and through which a rotation axis passes. The securement means 24 is mounted on the rotation means 25 and the sheet 13 therefore also rotates about the rotation axis in response to operation of the rotation means. The rotation axis preferably lies on a plane formed between the securement means 14 and the pivot 19 . In this manner, the object (sheet 13 ) rotates about an axis passing through at least the portion of the object that is secured by the securement means 24 . A first sprocket (not shown) is fixed to the shaft 26 and a second sprocket 28 is located outwardly of the first sprocket and rotatably attached to the rotation means 25 . The second sprocket 28 includes a radially extending dog 27 to which a pneumatic rotation cylinder 29 is attached so that extension or retraction of the cylinder causes rotational movement of the second sprocket 28 . The second sprocket 28 is linked to the first sprocket by an endless chain drive and, upon rotation, moves orbitally about the shaft 26 . This in turn causes the rotation means 25 to turn about the rotation axis. The relative size of the first and second sprockets and the stroke length of the pneumatic rotation cylinder 29 are selected so as to allow the rotation means 25 to turn a full 180°. This allows the sheet 13 to be flipped as needed for bending from either side. Since the shaft 26 is aligned with the pivot 19 , the rotation axis moves arcuately with the attachment 14 and rotation of the sheet 13 can be accomplished at any angular orientation. Persons skilled in the art will realize that this is but one embodiment of a rotation means that might be used in accordance with the present invention and that other variants might be used or the rotation means 25 might be omitted entirely. Referring to FIGS. 3 a and 3 b , the various parts of the attachment and manipulator apparatus that were previously described are shown in perspective view, with like parts being indicated by like reference numerals. This embodiment of the manipulator includes a sliding shuttle 30 to which the handles 23 are mounted. The sliding shuttle 30 is resiliently biased toward a neutral medial position and permits temporary upward and downward movement therefrom in response to operator movement of the handles 23 . At the upper and lower limits of travel of the shuttle 30 , a switch is engaged that actuates a slight increase or decrease in pressure, respectively, of the pneumatic lift cylinder. The pressure increase has the effect of gently boosting the manual raising of the object (sheet 13 ) to assist the operator in overcoming the inertia, friction and air flow restrictions of the manipulator system. A similar effect is observed upon pressure decrease when lowering the object. The need for boosting the otherwise neutrally buoyant object is exacerbated when particularly heavy objects are manipulated, as the components of the manipulator system increase in size to the point that inertia, friction and air flow restrictions become more significant relative to the strength of the operator. Referring to FIGS. 4 a and 4 b , a method of bending a sheet using the attachment 14 comprises first positioning the attachment adjacent the object (sheet 13 ) using the handles 23 and actuating the securement means 24 using the operator controls 22 . Once the sheet 13 is secured, the operator 18 lifts upwardly on the handles 23 , which in turn slides the shuttle 30 to its upper position and activates a pressure boost in the pneumatic lift cylinder to aid the operator 18 in manually lifting the sheet 13 . Once the sheet 13 is raised to its desired position, the operator stops lifting and the shuttle 30 naturally returns to its medial position, returning the lift cylinder to the second pressure. The sheet 13 is then neutrally buoyant and can be positioned within the press 15 . Upon activating the press 15 and bending the sheet, movement of the sheet is externally induced by the press and the attachment 14 passively moves arcuately about the pivot 19 in response to sheet bending. The vertical extension member 12 also moves vertically, causing an arcuate movement of the arm 3 relative to the mast 2 . Referring to FIGS. 4 c and 4 d , the sheet 13 is then removed from the press and the angular orientation of the sheet is actively adjusted by the operator 18 using the controls 22 to temporarily alter the pressure in the pneumatic tilt cylinder 20 in order to upwardly or downwardly tilt the sheet until the desired angular orientation is reached. The sheet 13 may be optionally rotated about the rotation axis in order to bend the sheet from the opposite side, if required. The rotation of the sheet 13 may be accomplished before, during or after active angular adjustment of the sheet. The sheet may then be re-inserted within the press 15 to make the next successive bend and this series of operations may be repeated as many times as necessary. Although the attachment 14 is depicted throughout the figures secured to an end of the sheet 13 for direct insertion into the press 15 , the attachment 14 could readily be secured to a side of the sheet 13 . In this case, the externally induced bending movement of the sheet 13 causes a passive rotation of the rotation means 25 in conjunction with vertical adjustment of the vertical extension member 12 . Similar considerations apply upon removal of the sheet 13 from the press, in that the rotation means 25 and/or the angular orientation may be actively adjusted to attain the desired orientation for the next successive bend. The foregoing describes preferred embodiments of the invention and other features and embodiments of the invention will be evident to persons skilled in the art. The following claims are to be construed broadly with reference to the foregoing and are intended by the inventor to include other variations and sub-combinations of the invention, even if not explicitly claimed.	Attachments for power assisted lifting devices capable of rigidly positioning an object in three-dimensional space, for example pneumatically assisted manually operated mechanical arm manipulators, wherein the attachment is capable of securing an object for remote positioning thereof. More particularly, an end effector for a pneumatic manipulator that is capable of both passively following the motion of a secured object and actively adjusting the position of the secured object in an arcuate direction relative to the attachment of the end effector to the manipulator. The end effector is able to rotate the object about an axis passing through the end effector that also moves arcuately with the end effector. The end effector is particularly useful in the bending of metallic sheets or plates using a conventional sheet metal brake, as the end effector is capable of both positioning heavy sheets in the brake and following the movement of the sheet as it is being bent. The end effector may be used in conjunction with the manipulator to remove the sheet from the brake, flip the sheet using the rotation feature, then re-position the sheet within the brake for making successive bends on the same sheet without necessitating release by the end effector.	1
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prefabricated formwork for concrete and more particularly to a collapsible prefabricated formwork for concrete walls. 2. Description of Prior Art The time-tested method of constructing concrete walls for buildings include the pouring of concrete into a formwork set up, in situ. This operation includes the erection of the formwork which includes a pair of vertical sheathing panels in a spaced relationship by means of connecting elements. Such formwork is either of the removable and thus reusable type or is of a lost form type wherein the formwork becomes part of the structure after the concrete is cured. A lost form of formwork utilizing sheathing panels of insulating material is called generally an insulating formwork. All known insulating formwork comprise a connecting element which connects the two sheathing panels. This type of formwork can be devided into two main categories depending on the arrangement between the connecting elements and the sheathing panels. The first category may be referred to as a hollow parallelepiped blocks. In this category, one can find a connecting element which is molded with the sheathing at the factory site and is sometimes referred to by the trademarks ARGISOL and MARENGO. The advantages of this first category is that it is not necessary to install the connecting elements at the building site since they are already molded at the plant or factory with the two sheathing panels. On the other hand, this type of formwork has serious disadvantages in terms of storage or transportation given the rather high volume/surface-of-formwork ratio. The second category is referred to as the planar solid slab formwork. In this category the connecting elements are normally rigid and are supplied separately from the sheathing panels which are in the form of the planar solid slabs. Examples of this category is shown in U.S. Pat. Nos. 4,604,843 and 4,888,931 and Canadian Patent 1,233,042. The disadvantages of this category of formwork is that the connecting elements must be assembled at the building site which increases the installation cost of the formwork. The formwork of both of these categories is subject to other disadvantages at the on-site installation, and that is the relative small dimensions of the modules. For example in order to erect a 10 m 2 formwork one must assemble 10 to 40 modules on site, depending on the type of formwork used, which increases the number of joints and the cost of installation. As far as the fabrication of these modules is concerned, various elaborate machining or molding procedures are required in order that the edges of the modules form proper joints on assembly. Attempts to overcome these disadvantages have been made wherein the smaller modules are assembled at the factory site to form larger formwork sections and transporting these to the building site. In such a case one encounters transportation problems in view of the high volume to formwork surface ratio. That is a large volume of forms must be carried for a relatively small formwork surface. Each of the forms are of course spaced apart and held there by the rigid ties such that one lands up transporting a great deal of air. On the other hand, once insulating formwork is being utilized, other tasks must be added such as the installation of reinforcement rods, vapor barrier, water proofing membranes, or filler strips. These additional tasks increase the installation costs and construction delays. 3. Summary of the Invention It is an aim of the present invention to provide formwork which can be rapidly installed and which takes the advantages of the above mentioned two categories of insulating formworks without the disadvantages. It is a further aim of the present invention to provide a prefabricated collapsible formwork which will reduce the amount of space required for storage or transportation as compared with the above prefabricated formwork. It is further aim of the present invention to provide a prefabricated formwork which includes vapor barriers, waterproof membranes, insulation, reinforcement and filler strips already included at the factory site, thereby reducing the installation costs and construction delays at the building site. It is a further aim of the present invention to provide prefabricated formwork modules which are of a greater size than those considered in the above two categories. It is a further aim of the present invention to provide a prefabricated or preassembled collapsible formwork which one assembles at the building site and readies to receive concrete as well as the outside finish covering and the interior finish covering. The construction in accordance with the present invention comprises a formwork for a vertical wall including a prefabricated formwork module for a vertical wall including a first sheathing panel, a second sheathing panel and a plurality of collapsible connecting elements anchored to each of the first and second sheathing panels and extending at least partially therebetween in a spaced apart relationship, the first and second sheathing panels including edges having joint means on edge areas for permitting the modules to be erected one to the other in edge to edge relationship, the formwork module and connecting elements being constructed such that during storage or transportation of the formwork modules, each formwork module is collapsed such that the first and second sheathing panel are adjacent one another with the connecting element collapsed and at the building site during assembly the first and second sheathing panels are spaced apart to the full extent of the connecting elements. A method in accordance with the present invention comprises the steps of selecting a first sheathing panel having edges, selecting a second sheathing panel with edges to form a formwork module, attaching the first ends of a plurality of collapsible connecting elements to the first sheathing panel in a spaced apart relationship such that the connecting elements have opposite ends extending from the interior face of the first panel, connecting the opposite ends of the collapsible connecting elements to the second sheathing panel such that the interior face of the second panel faces the interior face of the first panel and collapsing the first and second sheathing panels against each other for storage and transportation while separating the first and second panels to the full extent of the connecting elements during assembly thereof at a building site. More particularly the method includes assembling a plurality of formwork modules, including providing joint means at the edge areas of contiguous sheathing panels of adjacent formwork modules. In a more specific embodiment of the present invention there are provided bearing devices on the exterior of the first and second sheathing panels respectively and the connecting elements pass through the panels and abut the bearing devices. In a still more specific construction, the bearing devices are in the form of a filler strip and the sheathing panels are insulating panels. In a further specific embodiment, a concrete reinforcement in he form of a grid is assembled between the first and second sheathing panels at the factory site. Further, the vapor barrier and the waterproof membrane can be installed on the insulating sheathing panels at the factory site such that all of the component parts of the formwork can be preassembled at the factory site and the form can be collapsed for storage and transportation. The erection of the formwork at the building site consists of separating the first ad second sheathing panels and by maintaining the separation by inserting spacers therebetween and connecting the joints at the edge areas of the panels with adjacent panels. In a more specific embodiment the spacers could be collapsible spacers which are preassembled at the factory site and which can be deployed at the building site when separating the first and second sheathing panels. The invention is especially concerned with the preassembling of as many building components as possible on the formwork, at the factory site, and to use as much as possible, conventional building materials in order to avoid the necessity of molding processes such as for molding expandable polystyrene. It is an aim therefore to render the form construction as universal as possible. Certain advantages which can be noted from the present invention include: Reduced storage and transportation costs since the formwork utilizes collapsible connecting elements allowing the formwork to be collapsed, thereby reducing their respective volume to formwork surface ratio; A rapid and simple assembly of the prefabricated panels, and in particular a larger size module when using insulating sheathing panels, thereby reducing the number of assembling steps on the building site and the number of joints for a given formwork surface. For example to erect 10 m 2 of formwork only three modules are required under the present invention instead of the current 10 to 40 modules. The prefabrication of the sheathing panels is simple since no molding or machining of the panels is required. All that is required is to form holes through the sheathing panels. A new form mating joint is described which offers resistance to traction and compression and this in two or three perpendicular directions. The system allows for rapid assembling and in case of errors an equally rapid disassembling of the modules. Preassembling the vapor barriers, the waterproof membrane and the filler strips, both interior and exterior, as well as the concrete reinforcement at the factory site, eliminates having to provide for these steps at the building site, thereby reducing costs BRIEF DESCRIPTION OF THE DRAWINGS Having thus generally described the nature of the invention, reference will now be made to the accompanying drawings, showing by way of illustration, preferred embodiments thereof, and in which: FIG. 1 is a fragmentary vertical cross-section of a formwork for a concrete frame building having a wooden exterior facing and a gypsum panel interior facing in accordance with the present invention; FIG. 2 is a fragmentary vertical cross-section of another embodiment of the present invention and showing a metallic exterior facing and a gypsum panel interior facing; FIG. 3 is a fragmentary vertical cross-section of still another embodiment of the present invention and showing a metallic exterior facing and a wood panel interior facing; FIG. 4 is a fragmentary vertical cross-section of still another embodiment of the present invention and showing an exterior stucco facing and an interior ceramic tile facing; FIG. 5 is a fragmentary vertical cross-section of the present invention and showing yet another embodiment thereof and illustrating a brick exterior facing and an interior concrete facing; FIG. 6 is a fragmentary vertical cross-section of still another embodiment of the present invention and showing an exterior brick facing and an interior gyspsum panel facing; FIG. 7 is a vertical cross-section of still another embodiment of the present invention and having a stucco facing on one side thereof and a ceramic tile facing on the other side thereof; FIG. 8 is a fragmentary elevational showing a joint between two adjacent formwork modules of the present invention; FIG. 8A is a fragmentary enlarged vertical cross-section taken along lines A--A of FIG. 8; FIG. 8B is a view partly broken away of a detail shown in FIG. 8; FIG. 9 is a fragmentary elevational view of another embodiment of a joint between two adjacent formwork modules; FIG. 9A is an enlarged vertical cross-section taken along lines B--B of FIG. 9; FIG. 9B is a view partly broken away of a detail shown in FIG. 9; FIG. 10 is a fragmentary elevational view of another embodiment of a joint between two adjacent formwork modules; FIG. 10A is an enlarged fragmentary vertical cross-section taken along lines C--C of FIG. 10; FIG. 10B is a view partly broken away of a detail shown in FIG. 10; FIG. 11 is a fragmentary elevational view of still another embodiment of a joint between two adjacent formwork modules; FIG. 11A is an enlarged fragmentary vertical cross-section taken along lines D--D of FIG. 11; FIG. 11B is a view partly broken away of the detail of FIG. 11; FIG. 12 is a fragmentary elevational view of a joint between two formwork modules; FIG. 12A is a view partly broken away of a detail of FIG. 12; FIG. 12B is an exploded view in cross-section of the joint shown in FIG. 12; FIG. 13 is a vertical exploded cross-sectional view, partly broken away, and showing a joint in accordance with an embodiment of the present invention; FIG. 14 is an enlarged exploded cross-sectional view similar to FIG. 13 but showing another embodiment thereof; FIG. 15 is a fragmentary elevational view showing a joint of another embodiment of the sheathing panels of adjacent formwork modules; FIG. 15A is a fragmentary enlarged vertical cross-section taken along lines E--E of FIG. 15; FIG. 16 is an elevational fragmentary view of a corner module for the formwork of the present invention; FIG. 16A is a horizontal cross-section taken along lines F--F of FIG. 16; FIG. 17 is a fragmentary elevational view of a joint in accordance with a further embodiment of the present invention; FIG. 17A is a fragmentary vertical cross-section taken along lines G--G of FIG. 17; FIG. 17B is a view partly broken away of a detail of FIG. 17; FIG. 17C is a view of a further detail of an element shown in FIG. 17; FIG. 18 is a fragmentary elevational view of a further embodiment of the joint between two formwork modules; FIG. 18A is a horizontal cross-section taken along lines H--H of FIG. 18; FIG. 18B is a fragmentary vertical cross-section taken along lines I--I of FIGS. 18 and 18A; FIG. 18C is a view showing a detail of FIG. 18; FIG. 19 is a fragmentary elevational view of still a further embodiment of a joint between two formwork modules in accordance with the present invention; FIG. 19A is a fragmentary enlarged horizontal cross-sectional view taken along lines J--J of FIG. 19; FIG. 19B is a fragmentary enlarged vertical cross-sectional view taken along lines K--K of FIGS. 19 and 19A; FIG. 19C is a view showing a further detail of an element in FIG. 19; FIG. 20 is a fragmentary elevational view of a further embodiment of the joint between two formwork modules; FIG. 20A is a fragmentary horizontal cross-section taken along lines L--L of FIG. 20; FIG. 20B is a fragmentary enlarged vertical cross-section taken along lines M--M of FIG. 20; FIG. 20C is a view of a further detail of an element in FIG. 20; FIG. 21 is a fragmentary cross-sectional view taken through a typical form of the present invention showing an embodiment of the connecting element; FIG. 21A is an enlarged fragmentary cross-sectional view taken at right angles to the view in FIG. 21; FIG. 22 is a cross-sectional view similar to FIG. 21 showing another embodiment of the connecting element of the present invention; FIG. 22A is a cross-sectional view taken along lines N--N of FIG. 22; FIG. 23 is a fragmentary cross-sectional view similar to FIG. 21 showing still a further embodiment of a connecting element in accordance with the present invention; FIG. 23A is a cross-sectional view similar to FIG. 23 showing the form in a different operative position; FIG. 23B is a fragmentary enlarged cross-sectional view taken along lines O--O of FIG. 23A; FIG. 24 is a fragmentary cross-sectional view similar to FIG. 21 showing a further embodiment of the connecting element of the present invention; FIG. 24A is a fragmentary elevational view taken along lines P--P of FIG. 24; FIG. 25 is a fragmentary cross-sectional view similar to FIG. 21 showing still a further embodiment of the connecting element of the present invention; FIG. 25A is a fragmentary elevational view taken along lines Q--Q of FIG. 25; FIG. 26 is a fragmentary enlarged cross-sectional view similar to FIG. 21 but showing a still further embodiment of the connecting element of the present invention; FIG. 26A is a fragmentary enlarged elevational view taken along lines R--R of FIG. 26; FIG. 27 is a fragmentary cross-sectional view similar to FIG. 21 showing a still further embodiment of the connecting element of the present invention; and FIG. 27A is a cross-sectional view taken along lines S--S of FIG. 27. DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings and in particular to FIG. 1, fragments of two formwork joined together at a building site are illustrated wherein each formwork has an exterior sheathing panel 1 made of expanded polystyrene (EPS). An opposite interior sheathing panel 2 of similar insulating material is also shown. The exterior panel 1 and interior panel 2 are held together by flexible connecting elements 3. These flexible connecting elements 3 illustrated in the embodiment of FIG. 1 are made from multi strand metal cable. It is understood that the connecting elements can be made of other types of materials such as plastic. The connecting element 3 is meant to abut the exterior of sheathing panel 1 against a bearing block 4 and sheathing panel 2, against a bearing block 5. These bearing blocks 4 and 5 can be fabricated out of wood having square outline and dimensions of 89 mm×89 mm by 19 mm. It is understood that these bearing blocks can also be made of metal, plastic, or other material having the necessary structural resistance and the shapes and dimensions could be different. The connecting elements 3 are passed through the panels 1 and 2 to abut in the bearing blocks 4 and 5 as shown in the drawings. These are assembled at the factory site so that the formwork is prefabricated before shipping It is important that the connecting elements 3 be at least foldable so that the panel 2 can be collapsed onto the panel 1 for instance in the storage or transportation condition and then be expanded to the full extent of the connecting member 3 at the building site when it is being assembled. Another embodiment of the connecting elements is illustrated in FIG. 1 and this includes connecting elements 6 which are made up of a plurality of metallic monofilaments grouped together but spaced apart one from the other. These connecting elements retain the respective sheathing panels 1 and 2 by means of bearing blocks 7 and 8 respectively, also illustrated in FIG. 1. The bearing blocks 7 and 8 as illustrated are made of wood as are the bearing blocks 4 and 5. However the bearing blocks 7 and 8 are much thinner than the blocks 4 and 5 in view of the fact that the connecting elements 6 include several spaced monofilaments located at different locations on the bearing blocks 7 and 8. In the case of connecting elements 3, they are located at one location and either of blocks 4 and 5. These bearing blocks 4 and 5, and 7 and 8 are considered discontinuous blocks. On the other hand, the exterior surfaces of the sheathing panels 1 are provided with continuous all-purpose filler strips 9. These blocks are strips 9 having in the present embodiment a thickness of 19 mm and a width of 89 mm. The filler strip 9 is used for nailing the exterior wooden facing 10 and has a support for the sheathing panel and referred to as a continuous bearing strip A similar multi- purpose filler strip 11 is provided on the interior sheathing panel 2 and a connecting element 3 is connected to both filler strips 9 and 11. The filler strip 11 is used as a base for receiving screw-type fasteners for the interior gypsum panels 12 and for retaining the vapor barrier 13 which is mounted to the panel 2 at the factory site. Respective formwork modules are connected together at joint 24, that is at the edges of the respective sheathing panels 1 and 2. In the embodiment of FIG. 1 a male joint member 14 and female joint member 15 help to locate the panels at the joint 24. These elements 14 and 15 clearly can be made of wood as shown in the drawings or of metal or plastic or other combination of materials. The two sheathing panels 1 and 2 making up the formwork are held at a spaced-apart position against the connecting elements 3 by means of spacers. In FIG. 1, spacer 16 is placed therein at the building site during assembly. A string 17 is provided to remove the spacer 16 when it is no longer required. Spacer 18 is a permanent spacer installed in the form at the building site. The spacer 18 is shown with two notches for receiving reinforcement rods 19, and this combination is allowed to be lost in the concrete when it is poured. Another embodiment of the spacer is illustrated by the numeral 20. The spacer 20 includes a hinge 21 and a locking device 22 which locks the spacer 20 in its extended position when the formwork is installed at the building site. Spacers 18 and 20 are provided with plates 23 which are in contact with the interior faces of the sheathing panels 1 and 2. The concrete 25 is poured into place between sheathing panels 1 and 2. All of the components are pre-assembled at the factory site with the exception of spacers 16, 18 and 20 which are installed at the building site. The reinforcement rods 19, the concrete 25 and the gypsum panels 12, as well as the exterior wood facing 10 are installed at the building site. Referring now to FIG. 2 the external metallic facing 37 is fixed to metal filler strip 26. The filler strip 26 is a multi-purpose bearing strip that helps to support the exterior sheathing panel 27. The interior gypsum panels 28 are fixed to metallic filler strip 29 which is also a multi-purpose bearing strip which helps to support the interior sheathing panel 30 and which holds the vapor barrier 31 to the panel 30. The sheathing panels 27 and 30 are also held by the discontinuous bearing members 32 and 33. The bearing members 26, 29, 32 and 33 are connected by means of connecting elements 38 which are cables. The bearing blocks 39 and 40 are connected by connecting element 41 which is made up of a number of spaced-apart mono-filaments wires. The bearing elements can be made out of metal as shown in FIG. 2 or can be made out of other materials. The joints 34 are in the form of rabbet joints and the male joint elements also are bearing blocks as are the joint elements 36 to which a connecting element 38 is associated. Prefabricated temporary spacers 42 which are installed at the building site are provided to maintain the two sheathing panels 27 and 30 in their spaced extended position at the building site. Spacer 42 is provided with a wire 43 for the purpose of removing the spacer when it is no longer required The spacer is provided with a notch 44 to facilitate the installation thereof at the building site. The spacers 45 which also serves to separate the sheathing panels 27 and 30 are installed at the factory site and are deployed at the building site. The spacer 45 includes a mechanism provided with three hinges 46 and is provided with a blocking device 47. The concrete reinforcing structure 48 is assembled at the factory site in the form of a metallic trellis or grid. This grid 48 is parallel to the sheathing panels 27 and 30 and can be conveniently collapsed for storage and transportation when the panels 27 and 30 are collapsed against each other with the metallic grid work 48 sandwiched therebetween. When the formwork are being assembled at the building site the reinforcing grid 48 is properly located in a spaced relationship with the help of the notches 49 provided in the spacers. At the joints of the various formwork modules, the metallic reinforcing grid is overlapped as shown at 50. FIG. 3 shows a similar formwork with an exterior sheathing panel 51 made up of a rigid insulating material, i.e. expanded polystyrene (EPS) as a core 52 sandwiched between reinforcement coatings 53 which can be a wood chip sheet on the exterior face and a polymeric reinforcement coating 54 on the interior surface of the panel 51. These coatings are of course provided at the factory site. The interior sheathing panel 55 is made up of a composite material including a core 56 and coatings 57 and 58 which are held together by a chemical adhesive or by mechanical fasteners. For example the core 56 can be an extruded polystyrene material while the coating 57 is a pressed wood fiber glued to the core 56 and the coating 58 is a two-ply plywood glued to the core 56. The external sheathing panel 51 and the internal sheathing panel 55 are connected by means of collapsible connecting elements 59 which are rigid links connected by means of three hinges 60. The connecting element 59 is mounted to the sheathing panels 51 and 55 at the factory site along with the discontinuous bearing blocks 61 made out of plastic and the bearing blocks 62 made out of wood. The plastic bearing block 63 is connected to the wooden bearing block 64 by means of a flexible connecting element 65. The flexible connecting element 65 in this embodiment is made of a chain with metal chain links. The multi-purpose filler strips 66 serve as bearing blocks for the connecting elements 69 and also serve to receive screws for mounting the outer metallic facing 67. The filler strip 66 is attached to the filler/bearing block 68 by a collapsible connecting element 69 which is made up of a metallic chain 70 and several metal cables 71 in spaced apart relationship. The interior facing can be in form of a stained wood panel 72 fixed to the wooden filler strip 68 which is also a bearing block for the internal sheathing panel 55. The formwork joints are shown as rabbet joints at the edges of the panels 51 and 55 and are provided with bearing block 73 made out of plastic which also serve as the male joint elements. The bearing block 74 also serves as the female joint element and this is made out of wood and mounted to the panel 55. The elements 62, 64, 68 and 74 also retain the vapor barrier 81. The spacing of the panels 51 and 55 is provided by a link-spacer 75 having hinges and blocking mechanisms. The link-spacer 75 can also serve as a connecting element and is connected to filler members acting as bearing blocks as shown in the drawings. This link-spacer 75 is mounted at the factory site and deployed at the building site. The concrete reinforcing grid is installed at the factory site and includes a grid pattern of rods welded at 78 or by mechanical fasteners 79. The joints of the reinforcing grid is formed at the factory site by providing hooks 80. All of the components are preassembled at the factory site with the exception of the metallic exterior facing 67, the stained wood finishing facing 72 and the concrete 82 which is poured in situ. Referring now to FIG. 4 the exterior sheathing panel 83 is composed of an insulating material such as expanded polystyrene (EPS) 84 and a reinforcement grid 85. The reinforcement grid 85 is attached to the insulating panel 84 by mechanical fasteners or by chemical adhesives and the assembly thereof is done at the factory site. The internal sheathing panel 87 is composed of a rigid insulating panel 86 attached to a wood-chip panel 89 by means of mechanical fasteners 88. The vapor barrier 90 is installed at the factory between the layers 87 and 89. The two sheathing panels 83 and 86 are connected together by means of collapsible connecting members such as chain 91. Connecting element 92 is in the form of rigid links articulated at hinges. The length of the flexible elements 91 or 92 can be adjusted. For instance the chain 91 or member 92 is coupled through a discontinuous retaining member having a deformable opening in one direction. The numeral 93 represents this device and allows the possibility of adjusting the distance between the two sheathing panels of this formwork The connecting element 92 includes rigid links with hinges and has graduations 94 with weak points 96 in order to break off the length at predetermined lengths. The graduations 94 on the connecting element 92 can be coupled to a retaining device 95 having a deformable opening in one direction allowing the possibility of adjusting the length of the connecting element 92. The interior ceramic tiles facing 97 can be applied directly to the wood chip panel 89 with suitable glue or a mortar coating 98. The exterior facing 99 is made out of stucco reinforced with metallic slats 100. Spacing between the sheathing panels 83 and 86 is provided by means of the hinged spacer member 101 which is mounted at the building site. The concrete reinforcement is in the form of a metallic grid 102 maintained in place by means of the notches 103 on spacer 101. The joint of the grid is provided at the building site by allowing the overlapping of the grids at 104. The concrete is poured between the sheathing panels 83 and 86. As in other embodiments, all of the elements are preassembled at the factory site with the exception of the exterior and interior facings. FIG. 5 illustrates another embodiment of the formwork wherein exterior sheathing panels 106 comprises a rigid insulating panel of expanded polystyrene (EPS) 107 and a layer of wood chips 108 on the exterior surface thereof as well as on the interior surface 109. The exterior facing 110 is of brick and is connected to the bearing blocks 111 by conventional masonry connecters 121. The interior facing in this embodiment is the concrete wall. In order to obtain this interior facing, the interior sheathing panel 112 can be a new panel with a smooth interior surface in contact with the concrete. In order to reduce the purchase costs of a new panel 112 the bearing blocks 113 can be increased in size in order to allow for the reduction of the thickness of the sheathing panel 112 which is disposable. The sheathing panel 112 in this embodiment can be made of composite sheets such as MASONITE (trademark) or other similar material. The vapor barrier 114 is fixed to the sheathing panel 106 at the factory site. The concrete reinforcement structure 115 is assembled at the factory site in the form of a grid. The spacing between the sheathing panels 106 and 112 is provided by means of a link-spacer 116 which is collapsible and includes three hinges. The bearing blocks 111 and 113 are connected by means of connecting element 117 which is a collapsible link structure having hinges. After the concrete has been poured and the minimum curing time has passed, the temporary sheathing panel 112 as well as the bearing blocks 113 are removed. The connecting elements 117 and spacer 116 are provided with cones 119 and a weak point 120 allowing the devices to be broken off at a predetermined distance from the surface of the concrete. Reference will now be made to FIG. 6 which shows an exterior sheathing panel 131 connected to the interior sheathing panel 122 by collapsible connecting elements 123 which are of the flexible type. The sheathing panel 122 comprises a expanded polystyrene material (EPS) providing an insulated panel 124 covered with reinforcement coatings 125 and 126. The sheathing panel 131 is supported by two dimensional continuous support panel 127. This panel 127 can be made of a thin wood chip material or other similar material. The connecting element 123 is anchored to continuous bearing device 127 by mechanical anchors 128. The interior sheathing panel 122 is supported by a two dimensional continuous bearing panel 129. The vapor barrier 130 is retained by the panel 129. The interior facing is a gypsum panel and is fixed by means of a metal filler strip attached to the panel 129 at the factory site. The sheathing panel 131 and 122 are spaced apart by means of link-spacers 136. The exterior facing 134 is of brick and is connected to the continuous support device 127 by means of masonry connectors. The concrete is poured in situ and is reinforced by means of the metal grid 135 which is preassembled at the factory site. FIG. 7 shows a sheathing panel 137 composed of a plastic grid 138, a wood chip panel 139 and a fiber board 140. The panel 137 is connected to the sheathing panel 141 by means of collapsible connecting elements 142. The sheathing panel 141 is composed of a wood grid 143, a gypsum panel 144, and a rigid insulating panel 145. The grids 138 and 143 are assembled at the factory site with the connecting elements 142 and the link-spacers 146. The other components are assembled at the building site according to specific requirements of each project and depending on the availability of the materials. The grids 138 and 143 are the primary bearing elements. These primary elements 138 and 143 can be of plastic or wood, such as indicated, or can be made of metal or other suitable material. The stucco 147 is reinforced by metal slats mounted to the sheathing panel 137. The ceramic tiles 149 are applied to the panel 141. The concrete is poured in situ and is identified by the numeral 150. The concrete is reinforced by means of reinforcement rods 151. FIGS. 8, 8A, 8B, 9, 9A, 9B, 10, 10A, 10B, 11, 11A, 11B illustrate the joints between the various formwork modules at the building site. Longitudinal movement at the joint of the respective modules is prevented by means of male joint members 152A, 152B, 152C and 152D which are coupled with the female joint members 153A, 153B, 153C and 153D. These devices are also bearing blocks for the sheathing panels. The bearing devices are connected to the other sheathing panel by connecting elements 154A, 154B, 154C and 154D. The movement of the joint in the two transversal directions is prevented by female joint members 155A, 155B, 155C and 155D which are coupled with the male joint devices 156A, 156B, 156C and 156D. These male joint devices with respect to the transversal joint have an opening and closing feature which is based on deformation of the materials 157A, 157B, 157C and 157D. These components can all be composed of wood, plastic, metal, or other materials. In the drawings, for example, the components 152A, 153A, 152B and 152D are made of wood. Components 156B, 157B, 152C, 153C, 155C, 156C, 157C and 153D are plastic and components 155A, 156A, 157A, 154A, 153B, 155B, 154B, 154C, 154D, 156D, 157D are metal. FIGS. 12, 12A and 12B show a male longitudinal joint device 158 coupled with female joint device 159. The female transverse joint device 160 is fixed to the male device 158. Under a small amount of pressure, the device 160 opens and closes the male transverse joint device 161. Reference to FIGS. 13, 14, 15 and 15A. The vapor barriers or the waterproof membrane 162A, 162B and 162C are glued to the panels 163A, 163B and 163C through the thickness of the joint. An adhesive 164A and 164B is applied at the factory site. This adhesive is protected by a protecting paper 165A and 165B which is removed at the building site. An insulating device 166A and 166B breaks the thermal bridge with the connecting elements 167A and 167B which is made out of metal. Referring to FIGS. 16 and 16A. The corner hinges 168 are mounted at the factory site with panels 169 to form the exterior wall of the corner and the interior wall of the corner. These are connected by link-spacer elements 170 of the collapsible type which are connected to the hinged shaft 171. This assembly provides a variable angled module 172 which can be connected to contiguous modules, including sheathing panels 173 by joints 174. Referring now to FIGS. 17, 17A, 17B and 17C, the joints are shown as permitting longitudinal movement along the axis of the joint for a predetermined distance. This limited distance is as defined between the bearing devices 175 and 176. This provides for adjustment in case of imperfections in regard to the adjacent surfaces due for instance to the footings which might not be at level. The bearing devices 175 and 176 are connected from one sheathing panel to the other by means of a flexible connecting element 177. The movement of the joints in the transverse direction at the joint is prevented by the transverse female member 178 of the joint which are coupled with the male transverse joint device 179. A waterproof membrane 180 is applied at the factory site on all the exterior surfaces of the sheathing panels which are not in contact with the concrete. The membrane 180 can be in asphaltic emulsion or it can be of some other similar material. After the modules, including the sheathing panels, are assembled and adjusted the panels are fixed together by means of fasteners 181 as shown in FIG. 17C, by means of a hammer. FIGS. 18, 18A, 18B and 18C show a joint which provides for unlimited longitudinal movement along the axis of the joint because the bearing device 190 and the retaining member 182 extend along the length of the axis of the joint. The bearing device 183 is provided with a retaining means 184 which is coupled with the retaining device 182 to prevent against movement in the two transverse directions. With only light pressure, the retaining device 184 is opened and can be closed on the retaining member 182. The bearing devices 190 and 183 are connected to similar bearing devices on the other opposed sheathing panel forming the formwork by means of collapsible connecting elements 185. After the sheathing panels 186 and 187 of the respective modules have been adjusted in the longitudinal direction any further movement is prevented by applying fastener 188 by use of a hammer, at the building site. The fastener 188 is applied to the bearing devices 190 and 183 respectively. The fastener is illustrated in FIG. 18C. The waterproof membrane 189 is made of asphaltic emulsion and is applied at the factory site on all of the exterior surfaces of the sheathing panels which are not in contact with the concrete. The insulating sheathing panel 186 and 187 are reinforced by means of a reinforcement layer 191. The reinforcement layer has adequate properties to receive the waterproof membrane of asphaltic emulsion. Referring now to FIGS. 19, 19A, 19B and 19C. The fasteners 192 are movable. This permits the assembling of the modules from the exterior of the panel, thus following the normal surface direction of the formwork. Once the insulating sheathing panels 193 and 194 are in place, the fastener 192 is placed in the retaining devices 195 (which are preassembled at the factory site) located on the bearing devices 196 and 197. The retaining devices 195 can be opened and closed over the fastener 192 with a slight force. In the event that an adjustment is made, certain of the retaining devices 195 on the bearing device 196 are no longer usable and they must be replaced by fasteners 198 installed at the building site by use of a hammer. For further precaution, more fasteners 181 (shown in FIG. 17C) can be used to reinforce the joint. The bearing device 197 is connected to a similar bearing device on the other sheathing panel by means of a collapsible connecting element 199. The collapsible property of the connecting element 199 is made possible by using a flexible cable 200. The bearing device 196 is connected to a bearing device on the opposite sheathing panel by foldable connecting members 201. These connecting members 201 comprise rigid sections and hinges 202 to ensure the collapsible characteristic of the connecting element. The insulating sheathing panels 193 and 194 are provided with a reinforcement layer 203. The waterproof membrane is an asphaltic emulsion 204 and is applied at the factory site on all the surfaces that are exposed and not in contact with the concrete. With reference to FIGS. 20, 20A, 20B and 20C, the joint devices 205 and 206 are aligned with the ends of the sheathing panels 207 and 208. The device 209 is pivotable about the device 210 by removing the pin 211 from the two retaining devices 212. These two possibilities permit the assembling of the modules from the exterior and from the interior of the modules by following the normal direction of the surfaces of formwork. The assembling of the sheathing panels following the parallel direction of the formwork surfaces is always maintained since the device 209 opens and closes the device 213 under slight force. Adjustment along the joint is unlimited since the retaining piece 213 is in the direction of the length of the joint. After the assembling and adjustment of the panels of the module is completed, fasteners 214, shown in FIG. 20C, are added by means of a hammer in order to prevent movement in any direction. The bearing device 205 is connected with a similar bearing device on an opposite sheathing panel by means of a collapsible connecting element 215. This connecting element 215 is composed by a chain section 216 and a rigid link section 217. The bearing device 206 is connected to a similar bearing device on the other sheathing panel by means of collapsible connecting elements 218. The connecting elements 218 comprise flexible cable portions 219 and rigid links 220. The insulating sheathing panels 207 and 208 are reinforced on the exterior surfaces as well as on the interior surfaces by means of layers of reinforcement material 221. The waterproofing membrane is provided in sheets 222 which are installed on the panel at the factory site. The thermal bridge of the connecting element is broken by means of the layer of insulating material 223. Referring now to FIGS. 21 and 21A, the insulating sheathing panel 224 is connected to the insulating sheathing panel 225 by a collapsible connecting element 226. The connecting element 226 comprises two rigid links 227 articulated by means of three hinge means 228. The collapsible characteristic of the connecting element 226 is obtained by means of the three hinges 228. The configuration of the hinges 228 is in the form of two eyelets as shown. The connecting element 226 is fabricated from a cylindrical metal rod as shown or can be made from plastic or other material having a different shape. The insulating sheathing panel 224 is held by the bearing blocks 229. The thermal bridge of the connecting element 226, if metallic, is broken by means of a layer of insulation material 230 which forms the thermal break. Referring now to FIGS. 22 and 22A, the insulating sheathing panel 231 is connected to the insulating sheathing panel 232 by means of a collapsible connecting element 233. The connecting element 233 comprises rigid link parts 234 articulated by means of hinge means 235. Configuration of the hinges 235 can include a shaft which is common to the two rigid parts which turn about the common shaft as shown. The connecting element 233 can be fabricated from a metal plate such as shown. The connecting element 233 includes notches 236 to support the rods of the concrete reinforcement grid. The insulating sheathing panel 231 is supported by the bearing block 237. The thermal break is provided by means of an insulating layer 238 preventing a thermal bridge to the metal connecting element 233. Referring now to FIGS. 23, 23A and 23B, the insulating sheathing panel 239 is connected to a similar insulating sheathing panel 240 by means of a collapsible connecting element 241 which is somewhat telescopic. The collapsible connecting element 241 comprises a number of rigid elements of which one element can slide relative to the other. For example element 242 slides on element 243 by means of an eyelet 244 on the link 242. The course of movement is limited by the stop 245. The telescopic mechanism can be obtained by sliding one rigid element with respect to another as shown or it can be a mechanism which permits extension and contraction movement between the elements. The collapsible connecting element 241 can be fabricated from a cylindrical metal rod such as shown. In its collapsed position the connecting element 241, in its telescopic mode as shown in FIG. 23A, is contained within cavities 246. These cavities permit the formwork to be collapsed and occupy the minimum of volume during storage and transportation. Insulating sheathing panel 239 is retained by bearing blocks 247. A thermal break is provided by a layer of insulating material 248 provided over the end of the connecting element 241, thereby preventing a thermal bridge. Referring now to FIGS. 24 and 24A, the insulating sheathing panel 249 is connected to the insulating sheathing panel 250 by means of a collapsible connecting element having an adjustable length. The connecting element 251 is comprised of three rigid sections, namely section 252, section 253 and section 254, as well as to flexible sections, namely section 255 and section 256. The collapsible property of the connecting element 251 is provided by means of the two flexible sections, namely section 255 which is in the form of a chain and section 256 which is a cable. The configuration of the flexible sections can be a chain or a cable as shown. The length of the connecting element 251 is adjustable by means of an element 254 coupled to a retaining bracket 258. If it is required to have a connecting element of fixed length, that is non adjustable, sections 254 and 258 can be replaced by a section similar to section 252 during the fabrication thereof. Section 254 has several notches 257 which permit its coupling with the retaining bracket 258. The bracket 258 includes an opening having weakening slits. Thus, the opening will be enlarged only in the direction of forward movement of the section 254, that is from the concrete side to the bracket side by means of deforming the material forming the bracket surrounding the slits. In order to reduce the thickness of the required concrete wall, it is necessary to reduce the length of the connecting element by means of pulling on the section 254 in the forward direction. The retaining bracket 258 is fixed to the bearing block 259 which will supply the support for the insulating panel 250. The insulating sheathing panels 249 and 250 are of the same insulating material. However, the insulating panel 249 as shown is thinner than panel 250 as it is reinforced by a reinforcement layer 260 made up of a panel of chip board. The bearing block 261 is shown smaller than the bearing block 259 since the reinforcement layer 260 has a better resistance to compression than the insulating panel 250. A thermal break is provided for the connecting element 251 by means of an insulating layer 262. Referring now to the embodiment shown in FIGS. 25 and 25A, the insulating sheathing panel 263 and the insulating sheathing panel 264 are both connected together by means of a collapsible connecting element 265. The connecting element 265 comprises a foldable section 266 made of a metal cable attached to a plug device 267 made of insulating rigid plastic and a metal device 268. The foldable section 266 is preferably a metal cable as shown. The insulating sheathing panel 263 is supported by a lost bearing device 269. The bearing device 269 can be fixed to the sheathing panel 263 by means of an adhesive coating 270 as shown or by other mechanical fasteners. The plug 267 is fixed to the bearing block 269. The insulating sheathing panel 264 is retained by the temporary bearing strip 271. The bearing strip 271 is called temporary since it can be removed and recuperated after the concrete has been cured. This element 271 can be utilized in other similar construction projects. The temporary bearing strip 271 can be a piece of wood 19 mm×89 mm as shown or by other shape and material which is suitable. The element 271 will remain in good condition since no other work will be applied to this part. This is possible because the bearing strip 271 is maintained in place by the simple squeezing pressure exerted by the socket 268. The element 268 includes a jaw 272 which can be subjected to elastic deformation within a suitable limit. During the fabrication at the factory site, the jaw 272 is opened under pressure to introduce the bearing strip 271. After the pressure has been released the jaw 272 tightens against the block 271. The element 268 is retained in place by means of a bracket 273 and the configuration of the jaw 272. After the concrete has hardened the block 271 is removed from the jaw 272 by means of a hammer and can be reused. The use of the connecting element with the possibility of removing the bearing block will be very useful in many types of applications, especially where the concrete surface of the wall is to be decorative and including brick construction etc. Referring now to FIGS. 26 and 26A, the insulating sheathing panel 274 and insulating sheathing panel 275 are retained together by means of a collapsible connecting element 276. The connecting element 276 comprises a foldable section 277 which is connected to rod 278 and element 279. The foldable element 277 has the same configuration and characteristics as foldable element 266 in FIG. 25. The insulating sheathing panel 274 is supported by a lost bearing block 280 which is glued to the panel 274 by an adhesive coating 281. The collapsible connecting element 277 can be connected to element 278 by means of welding as shown or by other means. The thermal break for the metal connecting element 276 is provided by means of an insulating layer 282. The element 278 can be a metal rod. Insulating sheathing panel 275 is retained by means of temporary bearing strip 283. The temporary bearing strip 283 can have the same shape and configuration as element 271 shown in FIGS. 25 and 25A. If desired, temporary structural elements to erect the formwork, that is to align and rearrange the formwork before and during the pouring of the concrete, can be used as element 283. The element 283 can be a 89 mm×89 mm piece of wood having any useful length. Element 283 is installed at the building site by means of a hammer. In effect, the element 283 is introduced under pressure into the opening formed by the sheathing panel 275 and the retaining member 284. The retaining member 284 is recuperable after the concrete has been cured. The element 284 is provided with slot 285 and notches 286. During the erection of the formwork at the building site, element 284 is slipped into the space between the elements 287 and 288 of the device 279. During the fitting thereof the groove 285 is enlarged elastically on contact with the element 289 of element 279. The element 284 is blocked in its final position by means of the coupling of the notches 286 and the blocking element 289. The bracket element 279 is retained in place by means of collars 290 and 288. Referring now to FIGS. 27 and 27A, insulating sheathing panel 291 and insulating sheathing panel 292 are maintained in spaced apart position by means of a link-spacer 293 which is assembled at the factory site. The link spacer 293 is an articulated connecting element which is provided with retaining means 294 and a blocking mechanism which includes a female element 295 and a male blocking element 296. The link-spacer 293 includes all the usual articulated link elements such as rigid sections 297, 298, 299, 300 and hinges 301. The sheathing panel 291 is retained by bearing block 302. The panel 292 is retained by the bearing block 303. The thermal break of the metalic parts is provided by means of insulating layers 304. The connecting element function can be removed and the spacer function of the piece 293 retained by eliminating elements 297 and 300 and the bearing blocks 302 and 303. The spacer can have the retaining element 294 which exert a pressure on the insulating panel during the deployment at the building site as shown. The connecting function can be provided by an anchor mechanism or by chemical adhesive or a combination of the two. The blocking mechanism of the spacer can be provided by a female blocking element 295 fixed on a rigid element and the blocking male element 296 fixed on another element as shown. Any other anti-rotation devices can also be used. To facilitate the deployment of the spacer with a rod, section 299 is provided with a notch 305. The section 293 of the spacer can be fabricated from a metal plate as shown.	A prefabricated collapsible formwork module is assembled at a factory site, including the provision of a pair of sheathing panels which can be made of insulating material, as well as the mounting of the vapor barrier, the filler strips, bearing blocks, and flexible or collapsible connecting elements extending between the panels extending between the panels to retain the panels when they are being erected. The sheathing panels may also have a waterproof membrane applied thereto, and the concrete reinforcement is assembled between the sheathing panels at the factory site. When the formwork module is fully assembled, it is then collapsed, that is, by moving one sheathing panel against the other including collapsing the collapsible connecting elements and sandwiching the concrete reinforcement which is preferably in the form of a grid, and the formwork module can then be stored and transported to a building site. At the building site, the formwork module is spread apart to the full extent of the connecting elements and spacers are provided between the sheathing panels for maintaining the panels apart. Typical joint mating means are installed at the edge area of the sheathing panels to form joints with adjacent panels.	4
FIELD OF THE INVENTION This invention relates to shelving systems, and more specifically, to a shelving system that enables quick installation while at the same time providing features that hide edge and wall defects in the attachment surfaces and the shelving boards. BACKGROUND OF THE INVENTION Shelving systems are generally installed either by placing stringers along the wall surfaces and then attaching shelf boards or surfaces atop them, or by installing pre-fabricated systems such vinyl coated wire shelving systems, or laminated board shelving systems. All three of these shelving systems have drawbacks, however. The placement of stringers with boards atop them requires that the surfaces to which the stringers and shelves will be attached be relatively true, i.e., that they be relatively flat and straight. Additionally, as the stringers and shelf boards are cut to fit, the edges must be finished in order to ensure a professional appearance. The finishing process is time-consuming and adds to the cost of installing the shelving. Vinyl coated wire shelving systems, on the other hand, have an institutional look to them that many find unattractive. Also, the wide spaces between the individual vinyl coated wires allow small objects to drop through, a feature that is plainly inconvenient. Laminated board shelving systems possess many of the same drawbacks as stringer and board shelving systems. Furthermore, laminate board shelving systems are prone to chipping of the laminate surface during cutting and installation. Chipping of the laminate surface results in wasted materials and increased installation time. Therefore, a need existed for a shelving system having a well-finished professional look that would provide support for small items. A further need existed for a shelving system that would conceal the effects of out of true wall surfaces and edge irregularities or chips in the shelves from cutting. Yet a further need existed for a shelving system that would provide for a fast and efficient installation process while being very cost effective. SUMMARY OF THE INVENTION It is an object of the present invention to provide a shelving system having a well finished professional look that would provide support for small items. It is another object of the present invention to provide a shelving system that will conceal the effects of out of true wall surfaces and edge irregularities or chips in the shelves from cutting. It is a further object of the invention to provide a shelving system that would facilitate a fast and efficient shelving installation while being very cost effective. The foregoing and other objects, features, and advantages of the invention will be apparent from the following, more particular, description of the preferred embodiment of the invention, as illustrated in the accompanying drawings. BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS According to one aspect of the invention, a shelving system is disclosed. The shelving system, comprises: a shelf; a substantially U-shaped rear channel frictionally coupled to a rear edge of the shelf; a first shelf bracket having a plurality of wall attachment channels coupled to a first end edge of the shelf; a second shelf bracket having a plurality of wall attachment channels coupled to a second end edge of the shelf; and a center support member having a rotatable locking engagement member coupled below the shelf proximate a middle front underside portion of the shelf. According to another aspect of the invention, a method for providing a shelving system is disclosed. The method comprises the steps of: providing a shelf; providing a substantially U-shaped rear channel frictionally coupled to a rear edge of the shelf; providing a first shelf bracket having a plurality of wall attachment channels coupled to a first end edge of the shelf; providing a second shelf bracket having a plurality of wall attachment channels coupled to a second end edge of the shelf; and providing a center support member having a rotatable locking engagement member coupled below the shelf proximate a middle front underside portion of the shelf. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 a is a front side perspective view of a preferred embodiment of the shelving system of the present invention. FIG. 1 b is a back side perspective view of the shelving system of FIG. 1 a. FIGS. 2 a-f are overhead, inner side, bottom, outer side, front end, and rear end views, respectively, of a left hand shelf bracket of a preferred embodiment of the shelving system of the present invention. FIGS. 3 a-f are overhead, inner side, bottom, outer side, front end, and rear end views, respectively, of a right hand shelf bracket of a preferred embodiment of the shelving system of the present invention. FIGS. 4 a-d are overhead, side, bottom, and end views, respectively, of a shelf bracket cap of the shelving system of the present invention. FIG. 4 e is a close-up front elevation view of a shelf bracket cap of the shelving system of the present invention shown in FIG. 4 d. FIG. 4 f is a close-up side elevation view of a locking tab of a shelf bracket cap of the shelving system of the present invention shown in FIG. 4 b. FIGS. 5 a-f are overhead, bottom, back end, front end, right side, and left side views, respectively, of a center support shelf bracket of a preferred embodiment of the shelving system of the present invention. FIGS. 6 a-d are overhead, front end, side and back end views, respectively, of a center support strut of the shelving system of the present invention. FIGS. 7 a-f are top and bottom, side, front end, back end, and two perspective views, respectively of a shelving attachment anchor used in the shelving system of the present invention. FIG. 8 is a close-up perspective view of a right rear corner of a preferred embodiment of the shelving system of the present invention. FIG. 9 is a close-up perspective view of the rotatable locking engagement of the center support shelf bracket and center support strut of the shelving system of the present invention. FIG. 10 is a close-up side view of the center support strut locking member end and its engagement tab of the shelving system of the present invention. FIG. 11 is a close-up perspective view of the engagement of a shelf bracket cap locking tab engaged to the receiving slot of a shelf bracket of the shelving system of the present invention. FIG. 12 is a close-up side view of a U-shaped rear channel of the shelving system of the present invention. FIGS. 13 a-f are overhead, bottom, back end, front end, right side, and left side views, respectively, of a center support shelf bracket of an alternate embodiment of the shelving system of the present invention. FIGS. 14 a-f are overhead, inner side, bottom, outer side, front end, and rear end views, respectively, of a shelf bracket of an alternate embodiment of the shelving system of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the embodiment of FIGS. 1 a- 1 b, reference number 100 refers generally to the shelving system of the present invention. FIGS. 1 a- 1 b show the general configuration of one embodiment of the shelving system 100 . Thus, the components of the shelving system 10 include a shelf 120 , a right hand shelf bracket 122 , a left hand shelf bracket 124 , a center support strut 128 , a center support shelf bracket 130 , and a rear channel 132 . As will be explained in more detail below, the shelf 120 is bound on either short side by the shelf brackets 122 and 124 , is bound on the rear by the rear channel 132 , and is supported in a horizontal position both by the shelf brackets 122 and 124 , which are secured to opposing walls (not shown) and by the center support shelf bracket 130 , which abuts a bottom surface of the shelf 120 and which receives the center support strut 128 . The center support strut 128 is, in turn, secured to a wall (not shown) abutting the rear channel 132 . Moreover, in the embodiment shown in FIGS. 1 a- 1 b , the shelving system 100 additionally comprises a hanger bar 126 , coupled to the shelf brackets 122 and 124 and to the center support shelf bracket 130 . Referring now additionally to FIGS. 2 a-f and 3 a-f , the shelf brackets 122 and 124 are shown in detail. The shelf brackets 122 and 124 are mirror images of each other, with each comprising the same individual features. For this reason and for the sake of clarity, the features of the brackets 122 and 124 have been assigned identical reference numbers, and the discussion herein is intended to apply equally to both brackets 122 and 124 (referred to in this section as the “bracket 122 / 124 ”). It can be seen that the bracket 122 / 124 is substantially L-shaped in configuration when viewed from the side (see particularly FIGS. 2 b and 2 d and 3 b and 3 d ). The short side of the bracket 122 / 124 is the hangar bar support 152 which, as shown in FIGS. 1 a, 1 b, 2 b and 3 b, projects at an essentially ninety degree angle below the long side of the bracket 122 / 124 and the shelf 120 . The hangar bar support 152 comprises a walled hangar bar receiver 142 , which is configured to conform to the shape of and matably receive an end portion of the hangar bar 126 as shown in FIGS. 1 a- 1 b . For greater strength, a screw or bolt (not shown) may be inserted into each end of the hangar bar 126 through the opening 144 in the hangar bar support 152 . Attention is now given to the long side of the bracket 122 / 124 , which itself, when seen in cross-section from the end (see FIGS. 2 f and 3 f ), is itself substantially L-shaped. The bracket 122 / 124 is dimensioned to be attached to a wall (not shown) through elongated channels 140 , which channels 140 are located in a side wall 141 . When attached, the bracket 122 / 124 is oriented as shown in FIGS. 1 a- 1 b , with the hangar bar support 152 extending downward at an essentially ninety degree angle. In this configuration, the bracket 122 / 124 has a support surface 148 a projecting at an essentially ninety degree angle from the wall (not shown) to which the bracket 122 / 124 is attached. After attachment of the bracket 122 / 124 , a portion of the bottom of the shelf 120 will sit on the support surface 148 a , with the exposed side of the shelf 120 abutting the side wall 141 . The portion of the bracket 122 / 124 opposite the support surface 148 a is open, as is the portion opposite the side wall 141 , giving the bracket 122 / 124 its substantially L-shaped cross-section. This configuration allows the shelf 120 to be lowered onto the bracket 122 / 124 following attachment of the bracket 122 / 124 to a wall (not shown). During lowering of the shelf 120 on the bracket 122 / 124 , the exposed front side of the shelf 120 is sized and positioned to a front cap 150 located on the bracket 122 / 124 at the end thereof above the hangar bar support 152 (see FIGS. 2 a , 2 b , 2 e , 3 a , 3 b , and 3 e ). The front cap 150 prevents the shelf 120 from sliding forward off the bracket 122 / 124 . Referring additionally now to FIGS. 4 a-f , 8 and 11 , the shelf bracket cap 160 , which couples to the bracket 122 / 124 and locks the shelf 120 into position, is shown. The bracket cap 160 comprises a sheet 161 , which substantially corresponds in length and width to the support surface 148 a . The bracket cap 160 further comprises two locking tab assemblies 146 b , which are dimensioned to snap into corresponding receivers 146 a in the bracket 122 / 124 (see also FIGS. 2 a , 2 d, 3 a , 3 d ). FIG. 12 is a side view of the substantially U-shaped rear channel 132 . The rear channel is dimensioned to be friction fit over the rear edge of the shelf 120 , with projection 134 within the rear channel 132 causing the rear channel 132 to be relatively strongly retained relative to the shelf 120 . The rear channel 132 should preferably be positioned so as to conform to the shape of the wall (not shown) lying behind the shelf 120 , which wall may not be perfectly straight. Thus, the inside surface 131 of the rear channel 132 need not be flush with the rear edge of the 120 throughout its length, as necessary to give the appearance that the shelf 120 /rear channel 132 combination is flush with the rear wall (not shown). To accomplish its purpose of making the shelf 120 appear flush with the rear wall (not shown) by adapting to irregularities in the wall surface, the rear channel 132 should be made of a malleable, at least partially flexible material. Referring now to FIGS. 5 a- 5 f, the center support shelf bracket 130 is shown. The center support shelf bracket 130 , when coupled to the center support strut 128 (see FIGS. 6 a- 6 d ), provides additional support to the shelf 120 and, further, in one embodiment, additionally supports the hangar bar 126 (see FIG. 1 a ). The center support shelf bracket 130 generally comprises a plate 176 , which is dimensioned to be positioned flush against the bottom of the shelf 120 , and secured to the shelf 120 with a screw, nail, or appropriate anchor (not shown) through opening 178 . A main support arm 171 is connected at one end to the plate 176 , and at a second end to a substantially J-shaped hanger bar receiver 170 . (One advantage of the J-shape of the hangar bar receiver 170 is that it allows a user of the hangar bar 126 to slide hangars all the way along the length of the hangar 126 , without any impedance by the hangar bar receiver 170 , which does not extend over a top portion of the hangar bar 126 .) The center support shelf bracket 130 further comprises a center support strut receiver 172 , which is dimensioned to receive and lock the center support strut 128 (see FIG. 9 ). (Preferably, the center support shelf bracket 130 , including the main support arm 171 , plate 176 , hangar bar receiver 170 , and center support strut receiver 172 , comprises a single piece of molded plastic.). FIGS. 6 a- 6 d show the center support strut 128 . It comprises a main support 129 , which at its first end projects at an acute angle from a wall plate 182 , which wall plate 182 is anchored to a wall (not shown) through opening 184 , preferably using an anchor 500 of the type shown in FIGS. 7 a- 7 f. Referring additionally to FIGS. 9 and 10, there is located at the second end of the main support 129 is a male locking member 180 , which is dimensioned to mate with the center support strut receiver 172 . This mating is accomplished through the positioning of a nub 175 projecting outward from the male locking member into a conforming horizontal channel 174 a within the center support strut receiver 172 . The nub 175 is then moved along the horizontal channel 174 a to its end, and then the main support 129 is rotated upward, causing the nub 175 to enter a conforming vertical channel 175 , thus locking the center support strut 128 in position relative to the shelf 120 . It is following this locking step that the wall plate 182 and anchor 500 are finally positioned. Referring now to FIGS. 7 a- 7 f , an anchor 500 of the type preferably used in the installation of the shelving system 100 to a wall is shown. The anchor 500 comprises a main shaft 510 , head 516 , a lip 520 (having an external diameter greater than that of the channels 140 and the opening 184 ), a hollow receiver 512 (having an external diameter less than that of the channels 140 and the opening 184 and a length slightly greater than the thickness of standard sheetrock), and two ribbed anchor members 514 a and 514 b . During installation, a hole is drilled in the desired location having the diameter of the hollow receiver 512 . The anchor 500 is then inserted into the channel 140 or opening 184 until the lip 520 causes the anchor 500 to stop. At that point, securing may be completed by hammering the head 516 , causing the main shaft 516 to penetrate into the hollow receiver 512 , further causing the spreading of the two ribbed anchors 514 a and 514 b on the opposite side of the sheetrock. This spreading should prevent the anchor 500 from becoming dislodged during use of the shelving system 100 . In the preferred embodiment of the shelving system 100 , as shown in perspective in FIGS. 1 a- 1 b , the system includes a hangar bar 126 , as well as the hangar bar supports 152 (see FIGS. 2 b, d, e and f and 3 b, d, e, and f ) and the substantially J-shaped hanger bar receiver 170 necessary to support the hangar bar 126 . However, it may be desirable to install a shelving system 100 without the hangar bar 126 and associated support structure, for example where the shelving system 100 is not to be used in a closet environment. Thus, referring to FIGS. 13 a-f, center support shelf bracket 230 takes the place of the center support shelf bracket 130 described above. The center support shelf bracket 230 is identical to the center support shelf bracket 130 , with the exception that the center support shelf bracket 230 lacks a hanger bar receiver 170 and, correspondingly, has a shorter main support arm 271 . To illustrate that the other components of the center support shelf bracket 230 conform to those of the center support shelf bracket 130 , they have been given the same reference numbers. Referring now to FIGS. 14 a- 14 f, in the embodiment of the shelving system 100 lacking a hangar bar 126 , the bracket 122 / 124 is replaced by a single bracket 222 , useable on either side of the shelf 120 . The single bracket 222 is identical to the bracket 122 / 124 described above, with the exception that the hangar bar supports 152 (see, e.g., FIGS. 2 b , 2 d, 3 b , and 3 d ) are omitted. To illustrate that the other components of the single bracket 222 conform to those of the bracket 122 / 124 , they have been given the same reference numbers. Statement of Operation Installation of the shelving system 100 begins with a measuring of the space to be occupied, either a closet or another space bounded on three sides by walls or similar structures. The shelf 120 is then cut to fit the length of the space and the size of the bracket 122 / 124 (which bracket 122 / 124 can be manufactured in different sizes as needed). The left hand shelf bracket 124 and the right hand shelf bracket 122 are installed, preferably by positioning the anchors 500 within the channels 140 . (The channels 140 are preferably elongated for ease of installation, to allow for precise positioning of the bracket 122 / 124 during installation while the anchors 500 are being inserted but before they have fully locked the bracket 122 / 124 into position.) However, prior to positioning the left hand shelf bracket 124 and the right hand shelf bracket 122 into the space, it is first necessary to place the hangar bar 126 into position in the two hangar bar receivers 142 and, if desired, to anchor the hangar bar 126 into place through the openings 144 . The rear channel 132 is positioned onto the rear exposed side of the shelf 120 , with the projections 134 holding the rear channel 132 into position. At this point, the shelf 120 is lowered onto the bracket 122 / 124 , and the precise position of the rear channel 132 relative to the rear side of the shelf 120 may be adjusted to conform to the surface of the wall (not shown) lying behind the shelf 120 . Once the shelf 120 is in position, it may be locked into place with the shelf bracket cap 160 , which couples to the bracket 122 / 124 when the locking tab assemblies 146 b snap into corresponding receivers 146 a. At this juncture, or even at an earlier stage, the plate 176 of the center support shelf bracket 130 is attached to the bottom of the shelf 120 , preferably at substantially a middle portion thereof, and with the hanger bar receiver 170 engaging the hanging bar 126 . Next, the male locking member 180 is mated with the center support strut receiver 172 , by positioning the nub 175 into the horizontal channel 174 a within the center support strut receiver 172 . The nub 175 is then moved along the horizontal channel 174 a to its end, and then the main support 129 of the center support strut 128 is rotated upward, causing the nub 175 to enter a conforming vertical channel 175 , thus locking the center support strut 128 in position relative to the shelf 120 . The center support strut 128 is then anchored to the rear wall (not shown) through wall plate 182 , preferably using an anchor 500 . For the embodiment of the shelving system 100 lacking the hanging bar 126 , installation is the same, except that the brackets 122 and 124 are replaced with two brackets 222 , and the center support shelf bracket 230 replaces the center support shelf bracket 130 . While the invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form, and details may be made therein without departing from the spirit and scope of the invention.	A shelving system adapted to be quickly installed in a closet or similar space with a relative minimum of labor and finishing. The system includes a shelf, side brackets which are anchored to the side walls of the closet space, end caps adapted to lock into the side brackets and to securely retain the shelf in position, a U-shaped rear channel to cover the back of the shelf and to conform to irregularities in the rear wall surface, and a center shelf support having a rotating locking mechanism. In one embodiment, the shelving system includes a hangar bar, which is held in position by the side brackets and the center shelf support.	0
BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a hotplate intended to equip a cooker such as a hob comprising at least one gas burner. According to the invention, the hotplate is made of vitreous ceramic or of another material resistant to high temperatures and having a low coefficient of expansion. In order to simplify its explanation, the invention will be described with reference to vitreous ceramic plates. Such an explanation of the invention must not in any way lead to the invention being interpreted as being restricted to this material. 2. Description of the Related Art Gas cookers or hobs with gas burners, the top plate being made of vitreous ceramic, are known in the prior art. Such gas burners are, in the usual way, arranged in a structure, usually made of metal, known as the carcass and covered with a vitreous ceramic plate equipped with a surround which closes the structure. The objective in designing these cookers has been for them to be substitutes for more conventional cookers usually consisting of an enamelled sheet on which the gas burners are positioned and of a metal grating which covers them. This substitution has allowed this type of cooker to reach new aesthetic heights. Furthermore, the use of a vitreous ceramic plate makes cleaning easier. Thus, document EP-A 879 797, for example, discloses a device for mounting gas burners in holes made in a vitreous ceramic plate forming the upper part of a cooker. Document DE-U 298 05 620 describes such a cooker and, more particularly, mounting means that allow the gas burners to be attached to the vitreous ceramic plate with seals to make the connection between the vitreous ceramic plate and the gas burner. Again, document W097/00407 describes such a cooker in which the gas burners are surrounded by elements to support cooking utensils used for cooking food. Patent FR-B-2 735 562 describes cookers comprising a vitreous ceramic plate supporting the gas burners and also fulfilling the function of supporting the cooking utensils. It is also known practice for such cookers to be produced in which the cooking utensils are supported by the upper part of the gas burner. These various types of embodiment of cooker have gas burners associated with a vitreous ceramic plate which forms the main upper part of the cooker and have in common the ease of cleaning the upper surface, the latter being formed of a vitreous ceramic plate. The only zones of the cooker which remain difficult for the user in terms of upkeep are the zones containing the gas burners; specifically, these burners have to be at least partially dismantled then refitted in order to be cleaned satisfactorily. SUMMARY OF THE INVENTION The inventors have therefore set themselves the task of offering the possibility of providing a cooker comprising at least one gas burner and the upper part of which is formed of a hotplate, such as a vitreous ceramic plate, for which cleaning is made even simpler than is allowed by the currently known products. This objective has been achieved, according to the invention, by a hotplate, such as a plate of vitreous ceramic, intended to equip a cooker comprising at least one gas burner, the said vitreous ceramic hotplate comprising a zone intended to cover the gas burner and the said zone having orifices, designed, in particular, to form an air inlet to the gas burner and to allow the flames out. According to the invention, the gas burner is completely concealed by the hotplate and is therefore invisible to the user; such a design provides a twofold simplification to the cleaning of the cooker. Specifically, first of all, the gas burner, which is concealed, is protected from mess and therefore less likely to become soiled. Furthermore, when the user cleans the visible part of the cooker, he has simply to clean the hotplate, this considerably simplifying the operation by comparison with the cleaning of the cookers currently available. Furthermore, such a design of the cooker gives a new aesthetic appearance which follows the recent trends, namely a clean look with the least possible number of visible functional elements. Specifically, the cooker which has a gas burner shows only the orifices which, as already stated, are designed on the one hand to allow air to the burner and, on the other hand, to allow flames to be formed and to exit at the upper surface of the hotplate so as to heat the cooking utensils. Advantageously according to the invention, the orifices are holes and/or slots. Such orifices may be made by techniques known to those skilled in the art such as, in particular, laser cutting or waterjet cutting techniques. According to the various types of design, the orifices may either act simultaneously as air inlets and as flame outlets, or be split into two categories, the first forming the air inlet and the second the flame outlet. According to a preferred embodiment of the invention, the hotplate is capable directly, that is to say without intermediate elements, of supporting cooking vessels or utensils over the gas burner. A first variant of the invention makes provision for the zone covering the gas burner to be capable of contributing to supporting the cooking utensils. In this variant, this zone covering the gas burner may have at least one raised part on which a cooking utensil can rest, at least in part. A second variant makes provision for the hotplate to comprise bosses distributed at the periphery of the zone covering the gas burner. Thus, cooking utensils can rest on these bosses of which, for the cooking utensils to be properly stable, there are preferably at least three. According to a third variant, the invention makes provision for a combination of the first two variants, namely for the zone covering the gas burner to be designed to support cooking utensils in association with bosses distributed at its periphery. A first design of the invention consists in producing the hotplate in at least two separate elements, a first, essentially flat, element comprising at least one opening, in which the gas burner will be housed, and a second element intended to close off the said opening and forming at least part of the zone covering the gas burner. The second element may have the shape of a cap, the geometry of which remains arbitrary and chosen particularly for aesthetic considerations; the overall shape of this element may, for example, be circular, parallelepipidal, star-shaped, etc. This cap may be formed of an essentially flat upper part which is raised with respect to the plane of the first element, able in particular to at least contribute to supporting the cooking utensils, and of vertical or slightly inclined side walls. The upper part of the cap which may contribute to supporting the cooking utensils may be either smooth or may have a relief making it possible, for example, to avoid slippage. As a preference, the orifices are formed in the second element which may have the shape of a cap and more particularly in the side walls thereof. This assembly formed by the two elements that make up the hotplate needs to be correctly sealed where the two elements meet so that water, for example used to clean the visible surface of the hotplate, cannot penetrate inside. Furthermore, from a hygienic point of view, as such a plate is used for the preparation of food, it is necessary to avoid any risk of soiling so that germs will not proliferate. Provision is thus advantageously made for the two elements to be assembled via a seal, for example made of silicone, placed on the first, essentially flat, element, the second element coming into contact with this seal which is crushed under the weight of the said second element, sealing thus being achieved. Furthermore, one element may advantageously be fixed with respect to the other simply under the weight of the second element, and by indexing the latter with respect to the first element. It is thus possible to form a barrier, particularly against water, and as the attachment is simple, the two elements can be separated at any time for more intense cleaning and, in particular, to avoid the proliferation of germs at the seal. According to a second preferred design of the invention, the hotplate is essentially flat and has at least one deformed zone which has the orifices and which covers the gas burner. Also as a preference, the deformed zone represents, with respect to the main plane of the plate, at least one boss and/or one recess. This deformation of the plate advantageously includes an essentially flat part raised up with respect to the main plane of the plate. Advantageously also, it has roughly vertical or inclined side walls in which the orifices are made. Like the second element in the case of the two-element embodiment, the deformed zone may have an overall shape which is independent of its function and which may be chosen arbitrarily. The upper part which may advantageously be flat and at least partially contribute to supporting cooking utensils, may be either smooth or have a relief. This embodiment of the invention made as a single element with at least one deformed zone can be achieved according to the teaching of document FR-B-2 735 562. Whatever the embodiment of the hotplate according to the invention, it is clear that the said hotplate, associated with a gas burner, now leaves only orifices still showing. Specifically, according to the invention, there is now no burner emerging through the plate and possibly supported thereby, the burner being wholly located under the hotplate. A gas burner more particularly suited to this design is a burner with a high primary ventilation rate. The inventors have also envisaged simplifying the gas burner by using the zone that covers it to form part of the combustion chamber thereof. Specifically, for example the deformed zone of the hotplate may constitute the upper part of the combustion chamber. It is also possible, according to another advantageous embodiment, for this deformed zone also to substitute for the part of the burner which has orifices where the flames are formed, it being possible according to certain embodiments of the invention for the said deformed zone to itself have orifices designed for the passage of the flames. According to other embodiments, the inventors also make provision for electrical heating elements such as radiant elements to be associated with this design, these other elements being inserted between the gas burner and the hotplate. According to such embodiments, the electric heating element may be fixed, for example, to the upper part of the combustion chamber of the gas burner. This type of embodiment may allow electrical heating to be substituted for gas heating, for example for warming a dish. The invention also makes provision for making hotplates designed to equip hybrid cookers, that is to say ones which may have gas rings associated with radiant electrical, halogen and/or induction rings. For this type of hotplate, the inventors advantageously envisage producing all the zones intended to cover a cooking ring in the same way, that is to say in accordance with what has just been described, so as to offer a cooker with a uniform appearance. BRIEF DESCRIPTION OF THE DRAWINGS Other details and advantageous features of the invention will emerge hereinafter from the description of one exemplary embodiment of the invention with reference to FIGS. 1 and 2, which depict: FIG. 1, a schematic perspective view of a vitreous ceramic plate produced according to the invention, FIG. 2, an enlarged view of part of FIG. 1 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT To assist with their understanding, the figures are not to scale. FIG. 1 depicts a vitreous ceramic plate 1 made as a single piece and designed to form four gas rings at the four locations 2 which are in relief on the plate. The vitreous ceramic plate 1 also comprises four holes 3 which are designed for the spindles of the gas burner controls to pass through. The presence of the holes 3 and their location must not lead to the invention being interpreted in a restrictive way; they may indeed not be present, for example when the controls are installed independently of the plate or in the case of sensitive controls, and when they are present, their distribution may be different. The four locations 2 are produced according to the technique taught by patent FR-B-2 735 562 which describes a method for producing bosses by deformation forming an integral part of the vitreous ceramic plate. It is therefore apparent that, according to the invention, the vitreous ceramic plate will wholly cover the gas burners, which are fitted in a support carcass or surround not depicted in the figures, to form a cooker. According to variants of the invention and as explained hereinabove, it is possible to associate this type of vitreous ceramic plate with gas burners, the manufacture of which is simplified or at least scaled down; specifically, it is possible to make provision for a deformed part 2 of the vitreous ceramic plate to constitute at least the upper part of the combustion chamber of the gas burner. In the embodiment set out in the figures, the deformations 2 made have also the function of supporting the cooking utensils such as saucepans. The diameters likely to contribute to supporting are designed to have diameters that vary from one location 2 to another, as is the case in more conventional cookers; specifically, the diameters of the support elements or, more precisely, the diameters of the gas burners, are usually designed with dimensions which vary on one and the same cooker so as to be suited to cooking utensils or saucepans of different sizes. Thus, the upper surfaces 4 of the deformations 2 intended to cover the gas burners have been made flat to offer stable support to utensils such as saucepans. According to other embodiments, the surface of a deformation may itself have a more or less pronounced relief either to form a roughness and prevent slippage or to constitute point supports between which the air or the combustion gases can flow under the bottom of the cooking utensil. Better depicted in FIG. 2, which is an enlarged view of region A in FIG. 1, the deformations 2 according to this embodiment of the invention consist of an upper part 4 and of a side part 5 which forms an inclined plane. This inclined plane also has slots 6 distributed about the periphery of the deformation 2 . These slots 6 are produced after the plate has been deformed by any means known to those skilled in the art, such as waterjet cutting or laser cutting. The invention also makes provision, according to other embodiment variants, for the orifices or slots 6 to be produced before the plate is deformed. These slots 6 are designed, on the one hand, to form the output orifices for the flames and, on the other hand, to allow air to the gas burner. These slots 6 , as far as flame outlet is concerned, are superposed on or substituted for, particularly when the vitreous ceramic plate constitutes the top part of the combustion chamber, the flame outlet orifices of the burner. Specifically, and at least as far as appearances go, the flames, as far as an external observer, and particularly the user, is concerned, originate from these slots. This novel design of a cooker with gas burners therefore truly offers a new appearance, and does so also when using the burners because the flames seem to take shape on the vitreous ceramic plate. According to other embodiments, it is possible to separate the functions of supplying air to the burner and of letting the flames out, for example by forming two levels of orifices on the periphery of the deformation 2 . For example, it is possible to provide a lower level consisting of slots for the air inlet and an upper level allowing the flames out and consisting of holes also distributed around the entire periphery. It is also possible according to the invention to make provision for for all of these orifices 6 formed on the lateral part 5 of the deformations 2 to have an internal shape, not depicted in the figures, for example provided on the lower zone 7 , which forms a barrier against the ingress of liquid into the gas burner. Such an internal shape may be a simple inclined plane or a more complex shape defined particularly according to the shape of the orifices 6 , to their positions and to the inclination of the side wall 5 . This internal shape of the orifices 6 may be obtained directly during the stage of cutting the orifices 6 , or by later shaping. Such an embodiment of the vitreous ceramic plate 1 according to the invention therefore offers a surface consisting of a simple material and, according to this embodiment, made of a single element which, aside from having an appearance which is novel for cookers with gas burners, will very advantageously allow the upkeep of such a device to be simplified by comparison with the products which currently exist. As regards the upkeep or repair of the gas burners, and more generally of all the elements located under the vitreous ceramic plate when the cooker is produced, the inventors have advantageously envisaged an assembly with the carcass which allows easy access to the burners; such an assembly for example envisages a device of the hinge type which allows the vitreous ceramic plate 1 to be lifted up completely without fully detaching it from the carcass and therefore without any problem of refitting or repositioning it. Such a device is naturally accompanied by suitable seals around the entire periphery so as to provide sealing when the vitreous ceramic plate 1 is in the functional position. The vitreous ceramic plate 1 depicted in the figures must not lead to the invention being interpreted in a restrictive manner; specifically, the invention is aimed at any type of vitreous ceramic plate intended to cover at least one gas burner. Such a plate may therefore have one single location 2 or several depending on the cooker that is to be produced, the four-location embodiment being merely one example. Furthermore, the vitreous ceramic plate may also be intended to cover, in addition to one or more gas burners, other types of cooking element such as radiant electric, halogen and/or induction elements. The inventors have also envisaged keeping such a vitreous ceramic plate 1 , that is to say one with four deformed locations 2 , when, for example, two gas burners are associated with two radiant electric, halogen and/or induction heating elements, possibly without forming the orifices over the electrical elements. Such an embodiment makes it possible to maintain a uniform overall appearance of the vitreous ceramic plate. It is also possible to make such deformations 2 only over the gas burners and to keep the plate flat when it covers electrical elements, to guarantee that the various zones can be recognized.	A hotplate, such as a plate of vitreous ceramic, intended to equip a cooker having at least one gas burner, includes a raised zone intended to cover the gas burner. The raised zone includes orifices.	5
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of, claims priority to and the benefit of, U.S. Ser. No. 14/059,313 filed Oct. 21, 2013 and entitled “SYSTEM AND METHOD OF ADVERTISING FOR USE ON INTERNET AND/OR DIGITAL NETWORKING CAPABLE DEVICES.” The '313 application is a Continuation-In-Part Application of and claims priority to U.S. patent application Ser. No. 12/828,830, filed Jul. 1, 2010, and now issued as U.S. Pat. No. 8,566,817, which claims priority to and the benefit of U.S. Provisional Patent Application No. 61/309,690, filed Mar. 2, 2010, each of which are incorporated herein by reference in their entirety. FIELD [0002] This invention relates generally to methods of advertising, and more particularly to a system and method of advertising preferably for use with internet and/or digital networking capable devices (“IDNCD”). BACKGROUND [0003] It has been estimated that six out of every ten people worldwide have access to high speed internet with over four billion internet and/or digital networking capable devices in existence. Furthermore, over half a billion people worldwide have been able to access the internet through a mobile web device as of the year 2009 and that number continues to grow. However, even with the increase in users of both internet capable devices and those who have been able to access the internet through such a device, the current methods of sharing digital information simply have not been able to keep up with the times. Presently, both the manner and mode of advertising and delivering information to INDCD's has remained unchanged, and been provided to individual user's of these devices in the same format that has been in use for many years on websites and other digital media. [0004] Initially, screens on smaller web capable devices pose a problem when trying to share media content or advertising. In the often strained relationship between media content sharing and internet and/or digital networking capable devices, advertising must be agreeable to the user. When using an internet and/or digital networking capable device that has limited visual space, the less intrusive the advertising is to the user, the better the user's experience. Internet and/or digital networking capable device users are usually working on essential tasks or using a specific program to accomplish a task, and therefore, intruding with an advertisement during this time can be annoying and potentially aggravating to a user. [0005] Currently, internet and/or digital networking capable devices are untapped resources for advertising. For example, in India, mobile devices accounted for nearly ninety percent of all internet users in 2008. As such, brands are able to pinpoint and profile users much more efficiently on an internet and/or digital networking capable device. Additionally, advertising on an internet and/or digital networking capable device provides advertisers a much more intimate exposure to users. [0006] There are multiple reasons why mobile web advertising is increasing in popularity with large companies including that, mobile phones are highly personal and are always with the user, along with the most direct way an advertiser can connect with the public is through their mobile phone. [0007] The lack of competition on a mobile web page is one of the best aspects of mobile advertisement, since due to the small space a displayed advertisement will not have to share the page with other advertisers. While banner ads and pop-ups saturate websites, through a mobile interface, these advertisements may be displayed in a more user friendly and personal manner that is easy to read. [0008] Therefore, this small space for advertising gives a unique opportunity to advertisers, but is currently thought of as a detriment to this medium. There needs to be a unobtrusive way to use this mobile space to connect users and brands. SUMMARY [0009] The present invention allows for advertising to be displayed on internet and/or digital networking capable devices in a novel and unique manner. Advertisers will be able to display content and/or media on the screen of the device during the time between when a program or web page is requested and when it actually loads. In one embodiment, the system employs a plurality of internet connections, as well as servers, databases and other mediums employed by networks. The media content may be downloaded and/or cached on a device prior to display or it may be accessed in real time depending on the device and/or individual preferences of a user. The content or media will be triggered to display when a process occurs on the device which necessitates a pause while content or media is loaded or retrieved. [0010] Currently, this space is underutilized and is often populated by a simple phrase such as “loading . . . ”; the instant system is disposed to utilize this space. The method of the present invention is meant not to interfere with the process necessitating the loading or retrieving, but may continue after the process has finished if the programmer so wishes. The content or media that was originally requested, which necessitated the loading or retrieval process, is then delivered after the advertising ceases to display. [0011] The primary innovation of the present invention is the use of the underutilized “loading space”. Advertisers will be able to seamlessly integrate media into processes that are already necessary and occurring on internet and/or digital networking capable devices. The instant system and method creates a highly visible media space that will be more agreeable to the users of these devices than current methods. [0012] Instead of advertising above, below, to the sides, in the middle, on top, or using any of the current banner and pop-up methods, the present invention alters the delivery method. The present invention puts the advertising between the content and/or media during necessary functional delays such as loading new pages. The present invention is a response to the need for a more visible and at the same time less intrusive form of advertising on and/or digital networking capable devices. [0013] There has thus been outlined, rather broadly, the more important features of the system and method of advertising for internet and network capable devices in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto. [0014] In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. [0015] These together with other objects of the invention, along with the various features of novelty, which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS [0016] FIG. 1 is a block diagram illustrating a method for receiving multimedia/advertisement on an internet and/or digital wherein by selected/flagged displayed multimedia/advertisement is recorded. [0017] FIG. 2 is a block diagram illustrating a method for receiving multimedia/advertisement on an internet and/or digital networking capable device (IDNCD) wherein the content may be selected/flagged by a user initiated process and redirected. [0018] FIG. 3 is a block diagram illustrating a method for delivering multimedia/advertising content to an internet and/or digital networking capable device (IDNCD) wherein a system within the IDNCD or the device itself is disposed to manage a cache of multimedia/advertising content that is updated as necessary through a plurality of available digital networks. [0019] FIG. 4 is a block diagram illustrating a method for delivering multimedia/advertising content to an internet and/or digital networking capable device (IDNCD) wherein a multimedia/advertising content server is disposed to manage a cache of multimedia/advertising content on an IDNCD that is updated as necessary through a plurality of available digital networks. [0020] FIG. 5 is a block diagram illustrating a method for displaying multimedia/advertising content on an internet and/or digital networking capable device (IDNCD) wherein the content is retrieved by the device in real-time. [0021] FIG. 6 is a block diagram illustrating a method for updating the cache of multimedia/advertising content on an internet and/or digital networking capable device (IDNCD) wherein the cache of advertising content is updated on the device in the event that additional software, programs, apps, firmware is downloaded or installed. [0022] FIG. 7 is a block diagram illustrating a method for updating the cache of multimedia/advertising content on an internet and/or digital networking capable device wherein a server is disposed to transmit updated content directly to the device. [0023] FIG. 8 is a block diagram illustrating a method for receiving multimedia/advertisement on an internet and/or digital wherein the displayed multimedia/advertisement is interactive and the interaction can be recorded. DETAILED DESCRIPTION [0024] In the following descriptions, the present invention will be explained with reference to various example embodiments; nevertheless, these embodiments are not intended to limit the present invention to any specific example, environment, application, or particular implementation described herein. Therefore, descriptions of these example embodiments are only provided for purpose of illustration rather than to limit the present invention. [0025] The acts, modules, logic and method steps discussed herein below, according to certain embodiments of the present invention, may take the form of a computer program or software code stored on a tangible or non-transitive machine-readable medium (or memory) in communication with a control device, comprising a processor and memory, which executes the code to perform the described behavior, function, features and methods. It will be recognized by one skilled in the art that these operations, structural devices, acts, logic, method steps and modules may be implemented in software, in firmware, in special purpose digital logic, and any combination thereof without deviating from the spirit and scope of the present invention as recited within the claims attached hereto. The software or method steps can be performed on, and certain steps or processes displayed on, mobile devices (e.g., smartphones, tablets, etc.), desktop computers, laptops, etc., or a combination thereof, as understood by those of ordinary skill in the art. [0026] FIG. 1 illustrates a block diagram of a preferred embodiment of the instant invention 10 for a system and method of advertising for use on internet and/or digital networking capable devices. In this embodiment, a method for receiving multimedia/advertisement on an internet and/or digital networking capable device (“IDNCD”) is shown, wherein a selection and/or flagging of displayed multimedia and/or advertisement by either the system or an individual user is recorded. At step 100 an individual user of the system initiates the process by interacting with an IDNCD. At step 110 , the user initiates a process on the IDNCD, wherein the process includes a loading or scheduled time delay; in one embodiment, the process may include starting a software application on the IDNCD. At step 120 , a background or similar appearance is displayed on a screen of the IDNCD during the loading and/or scheduled delay upon initiation of the process in step 110 . At step 160 , the IDNCD redirects the user to the process that was initiated in step 110 once the loading and/or scheduled delay is complete; in this embodiment, the user is redirected to the software application that was loaded to begin to utilize the application. In conjunction with the user initiating the loading process at step 110 and the background being displayed at step 120 , a quantity of multimedia/advertisement content is disposed to load on the IDNCD at step 130 during a predetermined time period for the loading of the application. At step 140 , a quantity of multimedia/advertisement content is displayed on the screen of the IDNCD. At step 150 , the user is provided with an option to either select and/or flag the multimedia/advertisement content previously displayed on the IDNCD. Upon selection/flagging of the multimedia/advertisement content at step 170 , then a record of the selected multimedia/advertisement is kept for later use by the user of IDNCD. Conversely, if the user of the IDNCD makes a decision not to select and/or flag any of the multimedia/advertisement content, then the user is ultimately redirected to the completed process which was previously initiated by the user at step 160 . [0027] FIG. 2 illustrates a block diagram of a method for receiving multimedia/advertisement on an internet and/or digital networking capable device (“IDNCD”) wherein the content may be selected/flagged by a user initiated process and subsequently redirected. At step 200 an individual user of the system initiates the process by interacting with an IDNCD. At step 210 , the user initiates a process on the IDNCD, wherein the process includes a loading or scheduled time delay; in one embodiment, the process may include starting a software application on the IDNCD. At step 220 , a background or similar appearance is displayed on a screen of the IDNCD during the loading and/or scheduled delay upon initiation of the process in step 210 . At step 260 , the IDNCD redirects the user to the process that was initiated in step 210 once the loading and/or scheduled delay is complete; in this embodiment, the user is redirected to the software application that was loaded to begin to utilize the application. In conjunction with the user initiating the loading process at step 210 and the background being displayed at step 220 , a quantity of multimedia/advertisement content is disposed to load on the IDNCD at step 230 during a predetermined time period for the loading of the application. At step 240 , a quantity of multimedia/advertisement content is displayed on the screen of the IDNCD. At step 250 , the user is provided with an option to either select and/or flag the multimedia/advertisement content previously displayed on the IDNCD. Upon selection/flagging of a quantity of multimedia/advertisement content by the user, then at step 270 , there is an interruption in the user initiated process previously started at step 210 . Following interruption of the initiated process, the user of the IDNCD is redirected to the website or URL of the selected advertisement/multimedia content at step 280 . Conversely, if the user of the IDNCD makes a decision not to select and/or flag any of the multimedia/advertisement content, then the user is ultimately redirected to the completed process which was previously initiated by the user at step 260 . [0028] FIG. 3 illustrates a block diagram of a method for delivering multimedia/advertising content to an internet and/or digital networking capable device (“IDNCD”) wherein a system located within the IDNCD is disposed to manage a cache of multimedia/advertising content and wherein the system automatically updates the content as necessary through a plurality of available digital networks. At step 300 a user of the IDNCD may either initiate or conclude a multimedia/advertisement content display thereby prompting a cache management system at step 310 to initiate a process of determining whether it is necessary to provide an update to the multimedia/advertising content cache. At step 320 , the management system checks the cache of the multimedia/advertisement content. If the event that the system determines that no new content is needed then the system cycles back to the start at step 310 and awaits for further initiation. Conversely, when the system determines that an update is necessary then a request is sent at step 330 through a plurality of available digital networks to a multimedia/advertising content server in step 340 . At step 350 , the server is disposed to create an update for the IDNCD device cache or an entirely new packet of multimedia/advertising content that is sent back to the device through a plurality of available digital networks. At step 360 , the cache of the IDNCD is then updated with the updated or new digital multimedia/advertising content created in step 350 at which point the system cycles back to step 310 and awaits further requests. [0029] FIG. 4 illustrates a block diagram of a method for delivering multimedia/advertising content to an internet and/or digital networking capable device (“IDNCD”) wherein a multimedia/advertising content server is disposed to manage a cache of multimedia/advertising content on an IDNCD, wherein the cache is updated as required by the system through a plurality of available digital networks. At step 400 , the server initiates a notification to be transmitted to the IDNCD. At step 410 , the notification from the server is triggered, and subsequently transmitted through a plurality of available digital networks to the IDNCD in step 420 . At step 430 , the IDNCD or the user of the device responds to the notification initiated by the server and allows for the updates to be delivered to the IDNCD. At step 440 , the notification is transmitted back from the IDNCD to the multimedia/advertising content server through a plurality of available digital networks. At step 450 , the server is disposed to create an update for the IDNCD device cache or an entirely new packet of multimedia/advertising content that is transmitted to the device through a plurality of available digital networks. At step 460 , once the content reaches the IDNCD, the cache of the IDNCD is then updated in step 470 with the updated or new digital multimedia/advertising content. [0030] FIG. 5 illustrates a block diagram of a method for displaying multimedia/advertising content on an internet and/or digital networking capable device (“IDNCD”) wherein the content is retrieved by the device in real-time. This embodiment is preferably utilized when the network/internet connection available to the IDNCD possesses very high speed and has very small latency, reducing the overall time for this process to complete. At step 500 a user of the IDNCD determines that content is need, and initiates a request for content at step 510 . The content request from the IDNCD is in the form of a message sent through a plurality of available digital networks at step 515 , wherein the message is received by a multimedia/advertising content server, at step 520 . Upon receiving the message, the server creates a reply message containing all the data and content requested by the IDNCD at step 530 . The replay message prepared at 530 is transmitted from the server to IDNCD at step 535 , thereby completing the original request for content. [0031] FIG. 6 illustrates a block diagram of a method for updating the cache of multimedia/advertising content on an internet and/or digital networking capable device (“IDNCD”) wherein the cache of advertising content is updated on the device when additional software, programs, apps, firmware is either downloaded or installed. This embodiment may be utilized in conjunction with other methods of content delivery or when users are expected to download or update programs on their devices frequently. At step 600 , a user of the IDNCD or the device itself, requests a software update/download from a software repository available through a plurality of available digital networks at step 605 . At step 610 , the software repository prepares the software or update request and bundles the software with updated multimedia/advertising content at step 620 . The bundled software/multimedia content is transmitted to the device (or is made available to be downloaded directly from the device) through a plurality of available digital networks at step 625 . The IDNCD then installs or updates the software from the bundle and updates the devices multimedia/advertising content cache with the update at step 630 . [0032] FIG. 7 illustrates a block diagram of a method for updating a cache of multimedia/advertising content on an internet and/or digital networking capable device (“IDNCD”) wherein a server is disposed to transmit updated content directly to the device. At step 700 , the server possesses a quantity of multimedia/advertising content. At step 710 , the server prepares the updated content for the cache on the IDNCD. At step 715 , the prepared content by the server is transmitted through a plurality of available digital networks to the IDNCD. In this embodiment, the message transmitted to the device may be the content itself, or the universal resource indicator of the content to allow the device to initiate the actual download. Once the IDNCD receives the updated content at step 720 , the device uses the downloaded content to update the cache on the device, 730 . [0033] FIG. 8 illustrates a block diagram of a preferred embodiment of the instant invention 10 for a system and method of advertising for use on internet and/or digital networking capable devices. In this embodiment, a method for receiving multimedia/advertisement on an internet and/or digital networking capable device (“IDNCD”) is shown, wherein a user is provided with an option to interact with, select and/or flag multimedia/advertisement content being displayed, and record the user interaction. At step 800 an individual user of the system initiates the process by interacting with an IDNCD. At step 805 , the user initiates a process on the IDNCD, wherein the process includes a loading or scheduled time delay; in one embodiment, the process may include starting a software application on the IDNCD. At step 815 , a background or similar appearance is displayed on a screen of the IDNCD during the loading and/or scheduled delay upon initiation of the process in step 805 . At step 835 , the IDNCD redirects the user to the process that was initiated in step 805 once the loading and/or scheduled delay is complete; in this embodiment, the user is redirected to the software application that was loaded to begin to utilize the application. In conjunction with the user initiating the loading process at step 805 and the background being displayed at step 815 , a quantity of multimedia/advertisement content is disposed to load on the IDNCD at step 810 during the loading of the application. At step 820 , a quantity of multimedia/advertisement content is displayed on the screen of the IDNCD. At step 825 , the user is provided with an option to interact with the multimedia/advertisement content previously displayed on the IDNCD. Multimedia or interactive advertising content can include audio, video, image, or haptic content displayed or presented from an internet or digital network capable device where the user can interact with the content via the available input methods provided with the device, including keyboard or mouse input, touch or swipe input, location tracking, a microphone, an accelerometer, a gyroscope, and the like. This interaction can include playing a game (e.g., maze, puzzle, drawing, etc.), taking a survey, selecting or providing input in response to displayed questions, or selecting and/or flagging the multimedia/advertisement content previously displayed. Upon interaction with, or selection/flagging of, the multimedia/advertisement content at step 825 , then the interaction data or information can be recorded and kept for later use by the user of the IDNCD, or other users or server administrators, and the user is redirected at step 835 to the completed process initiated by the user. If the user of the IDNCD makes a decision not to select and/or flag any of the multimedia/advertisement content, then the user is ultimately redirected to the completed process which was previously initiated by the user at step 835 . [0034] The system and methods disclosed herein can include providing advertising for use on internet and/or digital networking capable devices via computer software, an internet website, a device application (or “app”), and the like. The multimedia or advertisement displayed can be interactive or non-interactive, and can be directed to services, promotions, or goods related to the software, website or app with which it is being displayed, or directed to unrelated third party services, promotions, or goods. The advertisements can be displayed in a limited display window or section, or as a full screen advertisement. [0035] For certain embodiments, the multimedia or advertising can be displayed as partially transparent or translucent (e.g., ghosted) such that the user initiated process (such as the loading process) is at least partially visible to the user in the background (full screen or limited window display). Moreover, for various embodiments, the displayed multimedia or advertising can be displayed even after the loading process is complete, for a predetermined time, until the user selects or provides an input to remove the advertisement, or until the user makes an input selection to proceed to the completed process. [0036] Further, the multimedia or advertising can be initiated simultaneously with the loading process or some time before or after the loading begins. Similarly, the multimedia or advertising can be stopped, e.g., cease displaying, before the loading process is complete, at the same time the loading process is complete, or a period of time after the loading process is complete. [0037] While the invention has been described in connection with what is presently considered to be the most practical and preferred example embodiments, it will be apparent to those of ordinary skill in the art that the invention is not to be limited to the disclosed example embodiments. It will be readily apparent to those of ordinary skill in the art that many modifications and equivalent arrangements can be made thereof without departing from the spirit and scope of the present disclosure, such scope to be accorded the broadest interpretation of the appended claims so as to encompass all equivalent structures and products. [0038] For purposes of interpreting the claims for the present invention, it is expressly intended that the provisions of Section 112, sixth paragraph of 35 U.S.C. are not to be invoked unless the specific terms “means for” or “step for” are recited in a claim.	A system and method of advertising for use on an internet and/or digital networking capable device, wherein the system allows advertisers to use a loading space generated during the initiation of a process on the device to post any media and/or advertising content during the time between when a program or web page is requested and when it actually loads.	6
FIELD OF THE INVENTION [0001] The present invention relates to self-centering rotating endodontic files for dental root canal procedures. BACKGROUND OF THE INVENTION [0002] When a root canal procedure is being performed, the pulp tissue and bacteria must be removed from the root canal of the tooth. Often the canals are curved, thus necessitating a cleaning file, which can bend as it negotiates further into the canal. [0003] Traditionally, files were hand held instruments having spiral fluting with triangular or square cross sections. [0004] The file was inserted into the canal and moved between the thumb and forefinger in incremental, reciprocating movements. [0005] Later, reciprocating machines, which mimic that hand motion, were used. Now, fully rotational driven hand pieces are used. [0006] Tapered rotating dental endodontic files are used to clean the inside of a root canal in endodontic procedures. Typically these files are tapered fluted bodies, with spiral fluted cutting surfaces providing a working surface for cleaning the conical interior of a root canal. [0007] Also traditionally, the files are twisted or ground before use to create the fluting. Generally, stainless steel files are twisted and nickel titanium files are ground (while clamped), because nickel titanium is superelastic with corresponding shape memory of the alloy, which makes a permanent twist difficult to achieve. [0008] The nomenclature for sets of files is based upon the geometry of the taper of the fluted files. The tapers are defined by the change in width of the fluted cone defining the file. For example, tapers usually vary in increments of the width in parts of millimeters per each increase in lengthwise length of the file. [0009] For example, an “02” file means that for every lengthwise millimeter change in length the width changes 0.02 millimeter. An “04” file means that for every lengthwise millimeter change in length the width changes 0.04 millimeter. An “06” file means that for every lengthwise millimeter change in length the width changes 0.06 millimeter. An “08” file means that for every lengthwise millimeter change in length the width changes 0.08 millimeter. [0010] In the past, the files have been made from stainless steel. Stainless steel files are easy to twist into a fluted configuration and honed to a point. However, the problem with stainless steel is that it lacks shape memory and superelasticity. That is, if bent out of shape, like a paper clip it remains in the bent shape. [0011] More recently, rotary endodontic files are made of nickel titanium, a metal alloy that has shape memory and superelasticity. However, nickel titanium files are hard to twist like stainless steel, because like a rubber band they tend to return to their original shape, and will “untwist.” Therefore, production of nickel titanium files involves isolating the pre-fluted file in a stationary position, where grinding wheels are applied to the file, such as CNC (computer numerically controlled) ROLLAMATIC machines. [0012] Moreover, U.S. Pat. Nos. 5,984,679 and 6,315,558 B1, both of Farzin-Nia et al, describe a new procedure, in which nickel titanium can now be twisted. [0013] A major problem with mechanically rotated endodontic files is that unless there is a non-cutting surface touching opposite portions of the inside of the canal being routed and cleaned by the rotating file, the file will erratically deviate off center within the canal, sometimes damaging or even perforating through the root canal wall, rendering root canal therapy impossible to achieve and the necessity for extraction of the tooth. [0014] For example, if the diameter of the tapered rotating file is less than the diameter of the portion of the tapered root canal where the working surface of the rotating file is being applied, the file may tend to erratically deflect and cause damage to the root canal wall, possibly permanently damaging the tooth. [0015] Attempts to solve this problem include providing rotating endodontic files with a “radial land” following the fluted cutting edge of the endodontic file. [0016] For example, the convex area following the cutting edge is known as the “radial land”, which is defined as a curved surface portion of a file behind the cutting edge, which extends out radially as far as the cutting edge. Variations of radial lands have the trailing end of the land cut back and recessed, hence they are called recessed radial lands. [0017] When viewed in crossection, these radial lands define a sector of a circle, i.e. a portion of the cross sectional circumference, which is the “radial land” or a “circumferential land.” The “land” is followed by a gap, and then there is provided another cutting surface followed by a trailing radial land. [0018] By contacting the previously cut wall of the root canal, these radial lands keep the rotating file centered while the cutting edges engage the dentin on the inside conical surface of the root canal. [0019] If one does not use radial lands, then there is a possibility that the diameter of the fluted file is less distinct than that of the root canal, which will cause sudden erratic movements of the rotating file bit, possibly damaging a tooth. [0020] Because of the consistent intermittent contact of opposite portions of the inner tapered root canal by the file, the file is “centered” in a proper orientation within the canal. [0021] Among related patents defining radial lands include U.S. Pat. Nos. 6,074,209 and 6,106,296, both of Johnson. Johnson '209 further attempts to reduce the locking and abrupt movement of the rotating endodontic file by providing zones of smaller diameters on a fluted working portion of the file, thereby reducing the total contact surface and hopefully reducing the stalling lock and jerking problems associated with torque. [0022] Among related patents include U.S. Pat. No. 4,850,867 and 6,261,099, both of Senia and Wildey. The Senia '867 patent has a non-cutting tip and a non-cutting segment at the opposite end of the tapered fluted working portion, but the non-cutting segment has a smaller diameter than the tapered fluted working portion. [0023] A cylindrical non-cutting shaft is shown in U.S. Pat. 5,762,497 of Heath. It acts solely as a shaft, does not engage the canal wall and therefore cannot help in self centering the file. In contrast to the present invention, Heath '497 requires radial lands for centering the file within the root canal. [0024] However, as noted before, if the diameter of an active cutting region is less than the inner diameter of a root canal being filed by a rotating endodontic file and the non-cutting portion is less than the cutting portion diameter, these files have a tendency to bounce off the inside of the canal and jerk erratically and suddenly sideways, causing trauma and deviating from the path of the root canal itself. [0025] Moreover, U.S. Pat. No. 5,947,730 of Kaldestad also describes a cylindrical non-cutting shaft at the proximal, non-tip end of the file above the fluted working portion therein. Kaldestad '730 also discusses the use of an annular stop in FIG. 3 therein to stop penetration. Furthermore, Kaldestad '730 discusses using a set of three files of sequential taper for preparation of a root canal. [0026] Unlike the present invention, Kaldestad '730 needs radial lands for self centering a file and does not disclose the use of governor collar to self center a file, and as well the fact that all of the files of Kaldestad '730 have a taper greater than 0.06 mm for larger apical preparations. [0027] Furthermore, Kaldestad '730 does not disclose use of a particular set of three files including a first file for opening a root canal, a second file for negotiating and cleaning the root canal and a third shaping file that provides the final taper to the root canal. OBJECTS OF THE INVENTION [0028] It is therefore an object of the present invention to provide a self-centering endodontic file, which does not require the use of trailing radial lands following respective cutting edges. [0029] It is also an object of the present invention to provide a set of files which minimizes the number of files needed by a dentist, wherein the files are sequentially organized depending upon the canal size of the patient. [0030] Other objects which become apparent from the following description of the present invention. SUMMARY OF THE INVENTION [0031] In keeping with these objects and others which may become apparent, the present invention is a tapered self-centering rotating endodontic file having three contact points, including one non cutting tip at the distal end and two contact points at the top above the fluted cutting file. The top portion is in the form of an annular governor collar, such as, for example, a truncated cone or cylinder, which merges into the handle. [0032] The annular governor collar has a limited height, of between about 1.0 mm to 2.0 mm, to allow a space above the cutting portion for accumulation of debris, which would not be possible with a continuous collar extending up to the handle. [0033] The self-centering endodontic dental file is superelastic for curved tapered intra-canal filing, and it does not require the use of a “radially extending” radial land trailing a cutting edge of the file. Hence, the rotating file of the present invention does not allow abrupt transverse movement of file against the inner wall of the canal. [0034] This self-centering feature is accomplished by providing the smooth, non-cutting annular governor portion on the file, away from the fluted cutting edges of the file. The governor is preferably a small, smooth, truncated cone portion or alternatively a smooth cylinder, which is provided on the file above the fluted portion, so that the governor can contact the inner walls of the canal as the cutting edges are cleaning and shaping internal dentinal walls of the canal. [0035] Unlike the generally triangular cross section of the fluted portion of the file, the smooth governor portion is circular in cross section. [0036] In certain embodiments for a truncated cone or a cylinder, the axis of the governor portion is parallel to and coextensive with the axis of the tapered fluted portion. [0037] In another embodiment, the truncated conical governor collar or the cylindrical collar may be oriented with an axis, which is not coextensive and parallel with the axis of the fluted portion, so that its axis is tilted, i.e., oriented at an angle off of the major axis of the fluted file. [0038] In addition, the self-centering tapered endodontic file is provided with a smooth non-cutting apex, so that during rotation, the file is self centered by the contact of the governor against the two opposite sides of the inner wall of the tapered root canal and thirdly by the contact of the smooth apex of the file with the converged bottom of the root canal. [0039] The invention also includes a color and numerically coordinated visually ergonomic set of groups of three files each for small, medium and large root canals provided with it. [0040] The reason for minimizing the number of files is because each root canal size needs only sequentially a first file for initially drilling into and opening the root canal, a second file for routing out most of the interior of the tapered root canal and a third file for finishing the shaping and cleaning of the root canal. [0041] The proximal tops of the files are identified with indicia such as “A”, “B” or “C” or “1”, “2” or “3”, such as, for a first file A for first enlarging the root canal orifice, a second file B for cleaning most of the interior of the tapered root canal and a third file C for finishing the shaping and cleaning of the root canal. [0042] The files are further color coordinated by aligned, slanted bands at the proximal non-cutting cylindrical ends of the files, wherein further the position of the band upon the top, middle or lower portion of the proximal non-cutting cylindrical ends of the file further defines the applicable order of the file to be used with a predetermined determination that the root canal is small, medium or large. BRIEF DESCRIPTION OF THE DRAWINGS [0043] The present invention can best be understood in connection with the accompanying drawings. It is noted that the invention is not limited to the precise embodiments shown in drawings, in which: [0044] [0044]FIG. 1 is a side elevation view of a prior art endodontic rotary file; [0045] [0045]FIG. 2 is a side elevation view of an endodontic rotary file of this invention (with the apical distal end tip shown separately for convenience) FIG. 3 is a horizontal crossectional sagital view of a non-cutting governor collar thereof, taken along view arrow lines “ 2 - 2 ” of FIG. 2; [0046] [0046]FIG. 4 is a horizontal crossectional sagital view of an active cutting region thereof, taken along view arrow lines “ 3 - 3 ” of FIG. 2; [0047] [0047]FIG. 5 is a side elevational view of an alternate embodiment of for a rotary endodontic file of this invention ( with the apical distal end tip shown separately for convenience); [0048] [0048]FIG. 6 is a tilted crossectional sagital view of a tilted non-cutting governor collar for the rotary endodontic file shown in FIG. 5, taken along view arrow lines “ 6 - 6 ” of FIG. 5; [0049] [0049]FIG. 7 is a horizontal crossectional sagital view of the tilted governor collar of the alternate embodiment shown in FIGS. 5 and 6, taken along view arrow lines “ 7 - 7 ” of FIG. 5; [0050] [0050]FIG. 8 is a partial side crossectional view of a tooth showing the loose fit of a prior art rotary endodontic file in a root canal thereof; [0051] [0051]FIG. 8A is a partial side crossectional view of a tooth showing a tight close fit of a prior art rotary endodontic file, shown working in a root canal; [0052] [0052]FIG. 9 is a partial side crossectional view of a tooth showing the tight close fit of the rotary endodontic file of this invention, shown working in a root canal; [0053] [0053]FIGS. 10A, 10B and 10 C are side elevation views of three different variations of shaft designs as used with endodontic files of this invention; [0054] [0054]FIG. 11 is a side elevation detail of an alternate embodiment of the file shown in FIG. 2, wherein the governor is a cylindrical section with non-tapered sides; [0055] [0055]FIG. 12 is a side elevation detail of an alternate embodiment of the file shown in FIG. 5 wherein the tilted governor is a cylindrical section with non-tapered sides; [0056] [0056]FIG. 13 is a top plan view of a holder annotated with a diagram showing a coordinated organization of sets of files into sets of files organized in overlapping inverted “Y” configurations for enlarging, cleaning and finishing the cleaning of respective root canals; [0057] [0057]FIG. 13A is a front elevational view in partial crossection of the area shown in the ellipse “13A” of FIG. 13; [0058] [0058]FIG. 14 is a side elevational view of a set of three files for enlarging, cleaning and finishing the cleaning and shaping of respective root canals of a specified size. DETAILED DESCRIPTION OF THE INVENTION [0059] [0059]FIG. 1 shows a prior art rotary endodontic file 101 having handle 102 , a short cylindrical non-cutting shank 103 and a tapered active cutting region 104 having a length La (typically 16 mm under International Standards Organization (ISO) standards). The combined length of cylindrical non-cutting shank 103 and a tapered active cutting region 104 is shown as length Lt. A cutting or non-cutting tip 105 may also be provided. It is further noted that the diameter Ds is equal to or less than the diameter D h of active cutting region 104 , so that the diameter D h of the widest portion of active cutting region 104 is not less than D S . [0060] Therefore, if the diameter D h of the active cutting region 104 is less than the inner diameter of a tooth canal being filed by rotating endodontic file 101 , the rotating endodontic file has a tendency to abruptly engage the side of the canal and move erratically and suddenly sideways, causing trauma to the tooth and deviating from the path of the root canal itself. [0061] Some prior art rotary endodontic files are provided with smooth, non-cutting radial land sections following a fluted cutting surface of active cutting region 104 to reduce the tendency to grab in the side of the canal and move erratically and suddenly sideways. However, providing trailing radial land sections upon a fluted cutting surface is difficult to configure and manufacture, as well as reducing overall efficiency of the file. [0062] In contrast, the rotary endodontic file 1 of this invention shown in FIG. 2 has simplified features to minimize or eliminate this problem of the tendency of rotating endodontic files to overly engage the side of the canal and move erratically and suddenly sideways. To solve this problem, a short non-cutting governor collar 3 has been added atop active region 4 and below shaft 2 . The governor collar is a tapered or non-tapered collar with respect to the axis of file. It is called a “governor” since it automatically positions the rotary file 1 in the center of the canal in a fashion analogous to the manner in which an engine governor automatically regulates the speed of an engine. A non-cutting tip 5 is also used. [0063] Use of a governor collar applies to a file length where the length of the working surface, (cutting region) is less than that of a standard file having a cutting region length L a of less than 16 mm because the governor collar 3 will keep a shorter file centered better. [0064] Furthermore, while shaft 2 of FIG. 2 is shown merging with the governor collar 3 , wherein shaft 2 has a diameter less than the diameter of the governor collar 3 , it is known that other configurations can be provided, wherein the diameter of the shaft is equal to the diameter of collar 3 (not shown). [0065] [0065]FIG. 3 shows a smooth circular crossection sagital cut of governor collar 2 . [0066] [0066]FIG. 4 shows a crossection sagital cut of the spiral twisted triangular active cutting region 4 . [0067] [0067]FIG. 5 shows an alternate embodiment of rotary file 10 of this invention. It differs from that shown in FIG. 2 by virtue of using a tapered but tilted non-cutting governor collar 12 between active region 13 and shaft 11 . A non-cutting tip 14 is also used here. [0068] [0068]FIG. 6 is a tilted sagital cut view in crossection perpendicular to the axis of collar 12 ; it is circular. [0069] [0069]FIG. 7 is a horizontal sagital cut view in crossection at the junction of shaft 11 and collar 12 . [0070] In addition, while shaft 11 is shown merging seamless with governor collar 12 , wherein shaft 11 has a diameter less than the diameter of governor collar 12 , it is known that other configurations can be provided, wherein the diameter of the shaft 11 is equal to the diameter of collar 12 (not shown), and wherein a distinct seam may be provided between shaft 11 and governor collar 12 (not shown). [0071] [0071]FIGS. 8, 8A and 9 contrast the fit of a prior art endodontic rotary file 22 within root canal 21 of tooth 20 with that of rotary file 1 of this invention. For example, FIG. 8 shows that prior art file 22 has annular space 23 between the top of the root canal and the active fluted region. This is a potential problematic area, which can lead to erratic engagement and eccentric movement of the fluted working surface of rotating endodontic file 22 . An unguided lateral (non-centered) movement of endodontic file 22 can cause damage to the wall of tooth 20 , possibly perforating tooth 20 . [0072] Also, FIG. 8A shows that the tip of file 22 will have difficulty following the distal curvature of canal 21 , and therefore file 22 will tend to deviate sideways into the wall of canal 21 . [0073] In contrast, according to the present invention shown in FIG. 9, endodontic file 1 has a more conformal tight close fit to canal 21 . Governor collar 3 , being the widest part above the cutting region smoothly and closely contacts two points of the continuous inner wall of canal 21 , which prevents cutting into the side of the top of root canal 21 as opposed to region 23 in FIG. 8. Also, non-cutting tip 5 will more easily follow distal curvature by not cutting into the wall of canal 21 . [0074] The combination of governor collar 3 contacting the wall of canal 21 at two points, plus the contact of non cutting tip 5 at the apical end of canal 21 , provides a three-point contact of non cutting surfaces of endodontic drill 1 with root canal 21 , thereby minimizing the risk of damage to tooth 20 due to lateral non-centered movement of rotating endodontic file 1 against the inner wall of canal 21 of tooth 20 . [0075] [0075]FIGS. 10A, 10B and 10 C show three different variations of shaft designs useful with any of the governor files of this invention. In addition, governor collars are short members wherein length L g is typically 1.0 to 2.0 mm. Just as shaft diameter D s is smaller than maximum active diameter D h in FIG. 1 to promote removal of debris from the root canal, the three shaft variations all have a diameter less than D m which is the maximum diameter of the governor. [0076] In FIG. 10A, shaft diameter D 1 is only slightly smaller than D m . [0077] In FIG. 10B, shaft diameter D 2 is significantly smaller than D m (and therefore more flexible). [0078] In FIG. 10C, shaft diameter D 3 is similar to D 2 , but it increases to D m more gradually. [0079] [0079]FIG. 11 shows an alternate embodiment using governor 53 which is comparable to governor 3 of FIG. 2 with the exception that governor 53 is now a parallel (cylindrical) section instead of a tapered (conical) section as is governor 3 . [0080] Similarly, FIG. 12 shows an alternate embodiment comparable to governor 12 in FIG. 5 wherein tilted governor 62 is now a parallel (cylindrical) section instead of the tapered (conical) section as in governor 12 . [0081] [0081]FIG. 13 shows a color and numerically coordinated visually ergonomic grouping of sets of three files, which are provided for each size canal of small, medium and large. [0082] The overlapping inverted “Y” configuration of FIG. 13 refers to the fact that files are either 21 or 25 mm in length. The left most inverted “Y” refers to the 21 mm length files and the right side inverted “Y” refers to the 25 mm length files. The three sets of overlapping inverted “Y”s refer to double sets of small, medium and large canal sizes in terms of width, wherein each set includes alternatively sets of files of 21 or 25 mm in length. [0083] [0083]FIG. 13 is actually a top plan view of a holder and organizer 70 for the endodontic files of this invention. It includes an annotated top sheet bonded to a substrate formed of a semi-rigid foam sponge block approximately 30 mm thick. [0084] [0084]FIG. 13A is a front crossectional view of a portion of large file set 74 in holder and organizer 70 , as depicted in ellipse “13A” of FIG. 13. [0085] The actual files are stored in the foam sponge block by driving the shafts through holes in the top sheet shown as dots in the three inverted “Y” displays marked “SMALL” set 72 , “MEDIUM” set 73 , and “LARGE” set 74 . The millimeter scales 71 are used as a measuring convenience. [0086] [0086]FIG. 14 shows a typical set 80 of three files with indicia “A”, “B” and “C”. The reason for minimizing the number of files to sets of three files A, B and C for a respective root canal is because each root canal size needs only sequentially a first file A for first enlarging the root canal orifice, a second file B for cleaning most of the interior of the tapered root canal and a third file C for finishing the shaping and last cleaning of the root canal. [0087] The proximal tops 82 , 84 and 86 of the files are identified with “A”, “B” or “C”. [0088] The preferred taper of the initial file 81 is about 0.05 mm while the preferred length of the active region Le is approximately 8 mm. [0089] The preferred taper for the second file 83 is about 0.04 mm while the length L n of the active region is dependent on the tip as shown in the table in FIG. 14, such as for example, between about 8 to 10 mm. [0090] The preferred taper of the third file 87 is about 0.06 mm while the length of the active region L f is approximately 14 to 16 mm. [0091] As further shown in FIG. 14, endodontic files A, B and C are further color coordinated by slanted, aligned bands B e , B n and B f at the proximal non-cutting cylindrical ends of the respective files 81 , 83 and 87 , wherein further the position of the respective band B e , B n or B f upon the top, middle or lower portion of the proximal non-cutting cylindrical ends of the respective files 82 (A), 83 (B) or 87 (C) further defines the order of use of each file A, B or C to be used with a predetermined determination that the root canal is small, medium or large. [0092] In the foregoing description, certain terms and visual depictions are used to illustrate the preferred embodiment. However, no unnecessary limitations are to be construed by the terms used or illustrations depicted, beyond what is shown in the prior art, since the terms and illustrations are exemplary only, and are not meant to limit the scope of the present invention. [0093] It is further known that other modifications may be made to the present invention, without departing the scope of the invention.	A tapered self-centering rotating endodontic file includes an annular governor collar, such as, for example, a truncated cone or cylinder, which merges into the handle. The file does not require the use of a radial land trailing a cutting edge of the file. Hence, the rotating file prevents damage from eccentric non-centered movement of file against the inner wall of the canal. The smooth, non-cutting annular governor portion is provided on the file, away from the fluted cutting edges of the file, so that the governor can contact the inner walls of the canal as the cutting edges are cleaning and shaping internal dentinal walls of the canal. Optionally, a set of files includes a first file for initially opening the canal, a second file for canal and a third file for finishing, shaping and cleaning the canal.	0
FIELD OF THE INVENTION The present invention relates generally to the purification of aqueous solutions, and more specifically, to electrochemical methods and more efficient and safer electrolytic apparatus for the destruction of pollutants in drinking water, industrial waste waters and contaminated ground water. BACKGROUND OF THE INVENTION Wastewater can be a valuable resource in cities and towns where population is growing and water supplies are limited. In addition to easing the strain on limited fresh water supplies, the reuse of wastewater can improve the quality of streams and lakes by reducing the effluent discharges they receive. Wastewater may be reclaimed and reused for crop and landscape irrigation, groundwater recharge, or recreational purposes. The provision of water suitable for drinking is another essential of life. The quality of naturally available water varies from location-to-location, and frequently it is necessary to remove microorganisms, such as bacteria, fungi, spores and other organisms like crypto sporidium; salts, heavy metal ions, organics and combinations of such contaminants. Over the past several years, numerous primary, secondary and tertiary processes have been employed for the decontamination of industrial wastewater, the purification of ground water and treatment of municipal water supplies rendering them safer for drinking. They include principally combinations of mechanical and biological processes, like comminution, sedimentation, sludge digestion, activated sludge filtration, biological oxidation, nitrification, and so on. Physical and chemical processes have also been widely used, such as flocculation and coagulation with chemical additives, precipitation, filtration, treatment with chlorine, ozone, Fenton's reagent, reverse osmosis, UV sterilization, to name but a few. Numerous electrochemical technologies have also been proposed for the decontamination of industrial wastewater and ground water, including treatment of municipal water supplies for consumption. While growing in popularity, the role of electrochemistry in water and effluent treatment heretofore has been relatively small compared to some of the mechanical, biological and chemical processes previously mentioned. In some instances, alternative technologies were found to be more economic in terms of initial capital costs, and in the consumption of energy. Too often, earlier electrochemical methods were not cost competitive, both in initial capital costs and operating costs with more traditional methods like chlorination, ozonation, coagulation, and the like. Earlier electrochemical processes required the introduction of supporting electrolytes as conductivity modifiers which adds to operating costs, and can create further problems with the disposal of by-products. Electrochemical processes in some instances have been ineffective in treating solutions by reducing concentrations of contaminants to levels permitted under government regulations. Heretofore, such electrochemical processes have often lacked sufficient reliability for consistently achieving substantially complete mineralization of organic contaminants, as well as the ability to remove sufficient color from industrial waste waters in compliance with government regulations. Notwithstanding the foregoing shortcomings associated with earlier electrochemical technologies, electrochemistry is still viewed quite favorably as a primary technology in the decontamination of aqueous solutions. Accordingly, there is a need for more efficient and safer electrochemical cell configurations and processes for more economic treatment of large volumes of industrial waste waters, effluent streams and contaminated ground water, including the decontamination of municipal water supplies making them suitable for drinking. SUMMARY OF THE INVENTION The present invention relates to improved means for electropurification of aqueous solutions, particularly effluent streams comprising waste waters polluted with a broad spectrum of chemical and biological contaminants, including members from such representative groups as organic and certain inorganic chemical compounds. Representative susceptible inorganic pollutants include ammonia, hydrazine, sulfides, sulfites, nitrites, nitrates, phosphites, and so on. Included as organic contaminants are organometallic compounds; dyes from textile mills; carbohydrates, fats and proteinaceous substances from food processing plants; effluent streams, such as black liquor from pulp and paper mills containing lignins and other color bodies; general types of water pollutants, including pathogenic microorganisms, i.e., bacteria, fungi, molds, spores, cysts, protozoa and other infectious agents like viruses; oxygendemanding wastes, and so on. While it is impractical to specifically identify by name all possible contaminants which may be treated successfully according to the claimed methods, it will be understood that language appearing in the claims, namely “contaminated aqueous electrolyte solution”, or variations thereof is intended to encompass all susceptible pollutants whether organic, inorganic or biological. The electropurification methods and apparatus for practicing this invention are particularly noteworthy in their ability to effectively purify virtually any aqueous solution comprising one or more organic, certain inorganic and biological contaminants present in concentrations ranging from as low as <1 ppm to as high as >300,000 ppm. Only electricity is required to achieve the desired chemical change in the composition of the contaminant(s), in most cases. The conductivity of tap water is sufficient for operation of the improved cell design. Hence, it is neither required, nor necessarily desirable to incorporate additives into the contaminated aqueous solutions to modify the conductivity of the solution being treated to achieve the desired decomposition of the pollutant/contaminant. Advantageously, in most instances solid by-products are not produced in the electropurification reactions as to create costly disposal problems. The improved electrochemical processes of the invention are able to achieve complete or virtually complete color removal; complete mineralization of organic contaminants and total destruction of biological pollutants even in the presence of mixed contaminants, and at a cost which is competitive with traditional non-electrochemical methods, such as chlorination, ozonation and coagulation, and thereby meet or exceed government regulations. Accordingly, it is a principal object of the invention to provide an electrolysis cell which comprises at least one anode and at least one cathode as electrodes positioned in an electrolyzer zone. The electrodes are preferably spaced sufficiently close as to provide an interelectrode gap capable of minimizing cell voltage and IR loss. Means are provided for directly feeding the contaminated aqueous electrolyte solution to the electrodes for distribution through the interelectrode gap(s). Means are provided for regulating the residency time of the aqueous electrolyte solution in the electrolyzer zone for modification of contaminants ether electrochemically by direct means and/or by chemical modification of contaminants to less hazardous substances during residency in the cell. Additional means are provided for collecting decontaminated aqueous electrolyte solution descending from the electrolyzer zone. It is also significant, the electrolysis cell according to the invention has an “configuration”. In addition to the electrochemical cell of this invention, further means are provided for practical and efficient operation, directly feeding contaminated aqueous electrolyte solution to the cell by pump means or by gravity; pretreatment means for the contaminated aqueous electrolyte solutions, for example, means for aeration, pH adjustment, heating, filtering of larger particulates; as well as means for post-treatment, for example, pH adjustment and cooling, or chlorination to provide residual kill for drinking water applications. In addition, the invention contemplates in-line monitoring with sensors and microprocessors for automatic computer-assisted process control, such as pH sensors, UV and visible light, sensors for biological contaminants, temperature, etc. It is still a further object of the invention to provide a system for purification of aqueous solutions, which comprises: (i) an electrolysis cell comprising at least one anode and at least one cathode as electrodes positioned in an electrolyzer zone. The electrodes are spaced sufficiently close to one another to provide an interelectrode gap capable of minimizing cell voltage and IR loss. Also included is a conduit means for directly feeding a contaminated aqueous electrolyte solution to the electrodes in the electrolyzer zone. The electrolysis cell is characterized by an open configuration. (ii) A control valve means for regulating the flow of contaminated aqueous-electrolyte solution to the electrodes directly via the conduit means of (i) above. (iii) Means are included for pumping contaminated aqueous electrolyte solution through the conduit means, and then (iv) rectifier means are included for providing a DC power supply to the electrolysis cell. The purification system may also include sensor means and computerized means for receiving input from the sensor means and providing output for controlling at least one operating condition of the system selected from the group consisting of current density, flow rate of contaminated aqueous solution to the electrolysis cell, temperature and pH of the contaminated aqueous electrolyte solution. Optional components include exhaust means for further handling of electrochemically produced gaseous by-products; means for pretreatment of the contaminated aqueous electrolyte solution selected from the group consisting of filtration, pH adjustment and temperature adjustment. As previously discussed, the electrochemical cells of this invention are especially novel in their “open configuration.” As appearing in the specification and claims, the expression “open configuration” or variations thereof are defined as electrochemical cell designs adapted for controlled leakage or discharge of treated and decontaminated aqueous electrolyte solution and gaseous or volatile by-products. The above definition is also intended to mean the elimination or exclusion of conventional closed electrochemical cells and tank type cell designs utilizing conventional indirect means for feeding electrolyte to electrodes. Closed flow type electrochemical cells, for example, are often fabricated from a plurality of machined and injection molded cell frames which are typically joined together under pressure into a non-leaking sealed stack with gaskets and O-rings to avoid any leakage of electrolyte from the cell. This type of sealed electrochemical cell is typically found in closed plate and frame type cells. Very close fitting tolerances for cell components are required in order to seal the cell and avoid leakage of electrolyte and gases to the atmosphere. Consequently, initial capital costs of such electrochemical cells, refurbishment costs, including replacement costs for damaged cell frames and gasketing from disassembly of closed plate and frame type cells are high. Because the configuration of the electrochemical cells of this invention is “open”, and not sealed, allowing for controlled leakage of aqueous electrolyte solution and gaseous by-products, sealed cell designs, including gaskets, O-rings and other sealing devices are eliminated. Instead, cell component parts are retained together in close proximity by various mechanical means when needed, including, for instance, clamps, bolts, ties, straps, or fittings which interact by snapping together, and so on. As a result, with the novel open cell concept of this invention initial cell costs, renewal and maintenance costs are minimized. In the open configuration cells of this invention, electrolyte is fed directly to the electrodes in the electrolyzer zone from a feeder which may be positioned centrally relative to the face of the electrodes, for example, where the contaminated solution engages with the electrodes by flowing through very narrow interelectrode gaps or spaces between the electrodes. During this period the contaminants in the aqueous solution are either directly converted at the electrodes to less hazardous substances and/or through the autogenous generation of chemical oxidants or reductants, such as chlorine, bleach, i.e., hypochlorite; hydrogen, oxygen, or reactive oxygen species, like ozone, peroxide, e.g., hydrogen peroxide, hydroxy radicals, and so on, chemically modified to substances of lesser toxicity, like carbon dioxide, sulfate, hydrogen, oxygen and nitrogen. In some instances, depending on the compositional make-up of pollutants in the solution being treated, it may be desirable to add certain salts like sodium chloride at low concentration to the solution before treatment in the cell. For example, this could be used to generate some active chlorine to provide a residual level of sterilant in the treated water. Likewise, oxygen or air may be introduced into the feed stream to enhance peroxide generation. Because electrolyte is fed directly to the electrode stack usually under positive pressure, gases such as hydrogen and oxygen generated during electrolysis are less prone to accumulate over electrode surfaces by forming insulative blankets or pockets of bubbles. Gas blinding of electrodes produces greater internal resistance to the flow of electricity resulting in higher cell voltages and greater power consumption. However, with direct flow of electrolyte to the cell, the dynamic flow of solution in interelectrode gaps, according to this invention, minimizes gas blanketing, and therefore, minimizes cell voltages. The aqueous solution entering the cell by means of pumping or gravity feed, cascades over and through available interelectrode gaps, and on exiting the electrolyzer zone of the cell through gravitational forces, descends downwardly into a reservoir, for post treatment, for example, or discharged, such as into a natural waterway. Any undissolved gases generated by electrolysis, in contrast, are vented upwardly from the cell to the atmosphere or may be drawn into a fume collector or hood, if necessary, for collection or further processing. While the direct feed “open configuration” electrochemical cells, as described herein, preferably provide for the elimination of conventional cell housings or tanks, as will be described in greater detail below, the expression “open configuration” as appearing in the specification and claims, in addition to the foregoing definition, is also intended to include electrochemical cell designs wherein the directly fed electrodes are disposed in the interior region of an open tank or open cell housing. A representative example of an open tank electrochemical cell is that disclosed by U.S. Pat. No. 4,179,347 (Krause et al) used in a continuous system for disinfecting wastewater streams. The cell tank has an open top, a bottom wall, sidewalls and spaced electrodes positioned in the tank interior. Instead of feeding the contaminated aqueous solution directly to the electrodes positioned in the tank the electrolyte, according to Krause et al, is initially fed to a first end of the tank where interior baffles generate currents in the wastewater causing it to circulate upwardly and downwardly through and between the parallel electrodes. Hence, instead of delivering electrolyte directly to the electrode stack where under pressure it is forced through interelectrode gaps between adjacent anodes and cathodes according to the present invention, the electrolyte in the open tank cell of Krause et al indirectly engages with the electrodes through a flooding effect by virtue of the positioning of the electrodes in the lower region of the tank where the aqueous solution resides. This passive, flooding effect is insufficient to achieve the mass transport conditions necessary for efficient destruction particularly of contaminants when present in low concentrations. Consequently, gaseous by-products of the electrolysis reaction can and often do result in the development of a blanket of gas bubbles on electrode surfaces. This generates elevated cell voltages and greater power consumption due to higher internal resistances. Accordingly, for purposes of this invention the expression “open configuration” as appearing in the specification and claims is also intended to include open tank type electrochemical cells wherein the electrode stack is positioned in the interior of an open tank/housing and includes means for directly feeding contaminated aqueous solutions to the electrodes. With direct feeding the housing does not serve as a reservoir for the contaminated aqueous solution which otherwise would passively engage the electrodes indirectly by a flooding effect. For purposes of this invention, it is to be understood the expression “open configuration” is also intended to allow for safety devices positioned adjacent to the electrochemical cells and purification systems, such as splash guards, shields and cages installed for minimizing the potential for injuries to operators. Hence, the confinement of the electrolysis cells or an entire water purification system of this invention inside a small room, for example, is also intended to be within the meaning of “open configuration” as appearing in the specification and claims. A further type of electrochemical cell design is disclosed by Beck et al in U.S. Pat. No. 4,048,047. The Beck et al cell design comprises a bipolar stack of circular electrode plates separated by spacers to provide interelectrode gaps ranging from 0.05 to 2.0 mm. Liquid electrolyte is fed directly to the electrode plates through a pipeline into a central opening in the electrode stack and then outwardly so it runs down the outside of the stack. However, the electrode stack is placed in a conjoint closed housing with a covering hood to avoid loss of gaseous reactants, vapors or reaction products. Thus, the closed configuration of the Beck et al cell does not meet the criteria of an “open configuration” cell according to this invention. While it has been pointed out the “open configuration” of the improved, highly economic electrochemical cell designs of this invention are based on the elimination of traditional closed cell designs, including plate and frame type cells and conventional tank type cells, as well as traditional partially open tank type cell designs, whether batch or continuous, it is to be understood, the expression “open configuration”, as appearing in the specification and claims, also contemplates electrochemical cells which may be modified with various inserts, barriers, partitions, baffles, and the like, in some instances positioned adjacent to cell electrodes, or their peripheral edges. Such modifications can have the effect of altering electrolyte circulation and direction, and increase residency/retention time, and therefore, affect the residency time and rate of discharge of electrolyte from the cell. Notwithstanding, such modified electrochemical cells which are made partially open fall within the intended meaning of “open configuration” when the electrodes per se remain substantially accessible. Representative modified electrochemical cell designs with electrodes which remain substantially accessible that are included within the definition for “open configuration” as appearing in the claims include modified, so called “Swiss roll cell” designs wherein, for example, the closed tubular containment for the electrodes, which are superimposed onto one another and rolled up concentrically, is removed, thereby forming an “open type Swiss roll cell”. It is yet a further object of the invention to provide a more efficient electrochemical cell design which can be used in effectively treating a wide spectrum of both chemical and biological contaminants in aqueous media, but also of varying concentration (from less than a few ppm to several thousand ppm) which is both economically competitive in capital costs and power consumption to more conventional water purification systems. The electrochemical systems and methods of the invention have such significantly improved economics, as to be readily adaptable to treating via continuous processes, large volumes of industrial waste waters from manufacturing facilities, such as chemical plants, textile plants, paper mills, food processing plants, and so on. Lower cell voltages and higher current densities are achieved with the highly economic, open configuration, especially when configured as monopolar electrochemical cells equipped with electrodes having narrow capillary interelectrode gaps. Generally, the width of the gap between electrodes is sufficiently narrow to achieve conductivity without extra supporting electrolytes or current carriers being added to the contaminated aqueous solutions. Thus, the need for adding supporting electrolyte to the contaminated aqueous electrolyte solution as supporting current carrier can be avoided. Because of the open configuration, as defined herein, the electrochemical cells of this invention can be readily configured to a monopolar design. This is especially advantageous since higher current densities would be desirable ih electrolyzing contaminated aqueous solutions having relatively low conductivities while still also maintaining low cell voltages. Likewise, the improved electrochemical cells of this invention may have a bipolar configuration, especially for large installations to minimize busbar and rectifier costs. It is thus a further object of the invention to provide for improved, more economic and safer continuous, semi-continuous or batch methods for electropurification of contaminated aqueous solutions by the steps of: (i) providing an electrolysis cell comprising at least one anode and at least one cathode as electrodes positioned in an electrolyzer zone. The electrodes are spaced sufficiently close to one another to provide an interelectrode gap capable of minimizing cell voltage and IR loss. Means are provided for direct feeding a contaminated aqueous solution to the electrodes in the electrolyzer zone. Means are provided for regulating the residency time of the electrolyte solution in the electrolyzer zone during electrolysis for modification of the contaminants. The electrolysis cell is characterized by “open configuration” as previously described; (ii) directly feeding into the electrolyzer zone of the electrolysis cell a contaminated aqueous electrolyte solution, and (iii) imposing a voltage across the electrodes of the electrolysis cell to modify, and preferably destroy the contaminants in the aqueous electrolyte solution. It will be understood that generally the process will include the step of recovering a purified electrolyte solution from the electrolysis cell. However, the invention contemplates direct delivery of purified aqueous solutions to a watershed, for example, or optionally to other post-treatment stations. As previously mentioned, the methods is performed in an open configuration electrolysis cell which may be either monopolar or bipolar configuration. BRIEF DESCRIPTION OF THE DRAWINGS For a further understanding of the invention and its characterizing features reference should now be made to the accompanying drawings wherein: FIG. 1 is a side elevational view illustrating a first embodiment of a direct feed, open configuration, controlled leakage electrochemical cell of the invention wherein the electrodes are positioned above a water collection vessel in a horizontal orientation; FIG. 2 is a side elevational view of the electrochemical cell of FIG. 1 except the electrodes are in a vertical orientation; FIG. 3 is a side elevational view illustrating a second embodiment of a direct feed, open configuration, controlled leakage electrochemical cell of the invention wherein the electrodes are positioned in the interior of an open cell housing; FIG. 4 is an exploded view of the electrode cell stack of FIG. 1 . FIG. 5 is a side elevational view of an electrode stack of the invention connected in a monopolar configuration; FIG. 6 is a side elevational view of an electrode stack of the invention connected in a bipolar configuration; FIG. 7 is an elevational view of an electrode stack compartmentalized with a separator, and FIG. 8 illustrates the results of electropurification of an aqueous solution of phenol decontaminated according to the methods of the invention, as performed in Example I DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning first to FIG. 1 there is illustrated an electrochemical cell 10 for purification of contaminated aqueous solutions, as previously discussed, represented by contaminated water 12 passing through inlet 22 . The contaminated water 12 is treated in the electrolyzer zone 14 of cell 10 which is illustrated in a fully open configuration allowing gaseous by-products of the electrolysis reaction, such as oxygen and hydrogen 16 to be released to the atmosphere. It may be desirable in some instances to collect certain potentially hazardous gases generated during the electrolysis reaction to avoid discharging to the atmosphere. Chlorine, for example, may be generated at the anode during electrolysis of aqueous effluent streams containing brine or sea water. Such gases can be recovered, for instance, by a vacuum powered hood device of conventional design (not shown) positioned adjacent to electrochemical cell 10 . The electrolyzer zone 14 includes an electrode stack 17 shown in a horizontal orientation in FIGS. 1 and 4, and comprises at least one cathode 18 and at least one anode 20 . Anodes 20 , for example, may also serve as end plates 21 for holding an assembly of electrodes, spacers, and separators, whenever used, into an assembled electrode stack 17 . Non-conductive electrode spacers 23 positioned between electrodes provide the desired interelectrode gap or spacing between adjacent anodes and cathodes. While FIGS. 1 & 4 of the drawings may be shown with only a central cathode with anodes on opposite sides of cathode 18 , for example, it is to be understood the electrode stacks may be formed from several alternating anodes, spacers, cathodes, and so on, with bolting means 25 running through the stack and end plates for maintaining the components in a structurally stable assembly. The end plates, electrodes and spacers may have a generally rectangular geometry. However, any number of possible alternative geometrical shapes and sizes are within the purview of the invention, including square, round or circular configurations, to name but a few. Contaminated aqueous electrolyte solutions are fed directly to the electrodes in electrolyzer zone 14 via supply line 22 . Supply line 22 is shown centrally positioned relative to anode/end plate 21 . The electrodes, which may be solid and planar, are preferably mesh/screen-type materials. This enables the aqueous electrolyte solutions entering the electrode stack to directly engage with the electrodes, and in so doing flow radially across the face of the individual electrode surfaces within the stack toward their peripheral edges. In addition, the entering solution usually flows axially, or normal to the longitudinal axis of the plane of the electrodes, so the contaminated aqueous solution simultaneously cascades over and through the electrode stack in a fountain-like effect to maximize contact with electrode surfaces in the process. Purified water 24 , free or virtually free of contaminants exiting electrolyzer zone 14 , can be collected in an open tank 26 , or funneled into a discharge line (not shown) for emptying into a natural watershed, etc. It will be understood the direct feed of contaminated aqueous solutions to the electrolyzer zone need not be centrally positioned relative to the electrode stack, as illustrated in FIGS. 1-4. Alternative direct feed routes include inverting the point of feed, so that contaminated aqueous solutions are fed from the bottom of the electrode stack, or at an oblique or obtuse angle to the planar surface of the electrodes. In addition, the direct feed entry point may also be axial with the edge of the planar surface of the electrodes wherein contaminated solution is delivered to the peripheral edge of an electrode stack. A convenient means for regulating the residency time of the contaminated aqueous solution in electrolyzer zone 14 and for controlling leakage of decontaminated and purified water 24 therefrom can be through valve 28 and/or pumping means of conventional design (not shown). The flow rate of contaminated water directly entering the electrode stack and exiting the stack as decontaminated water can be regulated through manual or automated flow control valve 28 of standard design. The flow rate (liters/minute)is adjusted, so it is sufficient to provide effective destruction of pollutants by the time the treated solution exits the electrolyzer zone. Persons of ordinary skill in the art having the benefit of this disclosure will also recognize the performance of the electrochemical cells of this invention may be optimized by alternative means, such as increasing the path of the solution in the electrolyzer zone. The installation of baffles, for instance, can increase the dwell time of the solution in the electrolyzer zone. Alternative means include enlarging the surface area of the electrodes for reducing the residency time in the electrolysis zone. In practice, electrochemists skilled in the art will also recognize the performance of the cell can be increased with higher current densities. Because of cell geometry, and the ability to conveniently use both monopolar and bipolar configurations, practically any electrode material can be employed, including metals in the form of flat sheet, mesh; foam or other materials, such as graphite, vitreous carbon, reticulated vitreous carbon and particulate carbons. This also includes combinations of electrode materials, such as bilayer structures comprising two metal layers separated by appropriate insulating or conductive materials, and so on. Representative examples of useful anodes would include those generally known as, noble metal anodes, dimensionally stable anodes, carbon, vitreous carbon and graphite-containing anodes, doped diamond anodes, substoichiometric titanium oxide-containing anodes and lead oxide-containing anodes. More specific representative examples include platinized titanium noble metal anodes; anodes available under the trademark DSA-O 2 , and other anodes, such as high surface area type anodes like felts, foams, screens, and the like available from The Electrosynthesis Co, Inc., Lancaster, N.Y. Other anode materials comprise ruthenium oxide on titanium, platinum/iridium on titanium, iridium oxide on titanium, silver oxide on silver metal, tin oxide on titanium, nickel III oxide on nickel, gold, substoichiometric titanium oxides, and particularly the so called Magneli phase titanium oxides having the formula TiO x wherein x ranges from about 1.67 to about 1.9. A preferred specie of substoichiometric titanium oxide is Ti 4 O 7 . Magneli phase titanium oxides and methods of manufacture are described in U.S. Pat. No. 4,422,917 (Hayfield) which teachings are incorporated-by-reference herein. They are also commercially available under the trademark Ebonex®. Where electrocatalytic metal oxides, like PbO 2 , RuO 2 , IrO 2 , SnO 2 , Ag 2 O, Ti 4 O 7 and others are used as anodes, doping such oxides with various cations or anions has been found to further increase the electrocatalytic oxidation behavior, stability, or conductivity of the decontamination reactions of this invention. The selection of appropriate anode materials is made by considering such factors as cost, stability of the anode material in the solutions being treated and its electrocatalytic properties for achieving high efficiencies. Suitable cathode materials include metals, such as lead, silver, steel, nickel, copper, platinum, zinc, tin, etc., as well as carbon, graphite, Ebonex, various alloys, and so on. Gas diffusion electrodes are also useful in the methods of this invention. In this regard, they may be used as cathodes in converting oxygen or air to useful amounts of peroxide, minimizing hydrogen evolution and/or for lowering cell voltages. The electrode material, whether anode or cathode, may be coated with an electrocatalyst, either low or high surface area. Higher surface area electrodes, for example, expanded metal screens, metal or graphite beads, carbon felts, or reticulated vitreous carbon are especially useful in achieving higher efficiencies for destruction of toxic or hazardous substances when present at low concentrations in the aqueous electrolyte. Specific anode and cathode materials are selected on the basis of cost, stability and electrocatalytic properties. For example, persons of ordinary skill in the art of electrochemistry will recognize which electrode material to select when it is desired to convert chloride to chlorine; water to ozone, hydroxyl radicals or other reactive oxygen species; oxygen or air to hydrogen peroxide or hydroxyl radicals via electrochemically generated Fenton's reagent using for instance, a slowly dissolving iron-containing_metal anode; and catalytic reduction of nitrate to nitrogen or of_organohalogen compounds to halide ions and organic moieties of lesser toxicity. Of special importance in the selection of electrocatalytic anode and cathode materials occurs when treating aqueous solutions comprising complex mixtures of pollutants wherein electrode materials may be selected for paired destruction of pollutants. For example, an aqueous stream contaminated with organics, microorganisms and nitrate pollutants may be treated simultaneously in the same electrochemical cell using paired destruction methods with a reactive oxygen species generating anode, such as platinum on niobium or Ebonex for destruction of microorganism and oxidation of organics. In addition, the same. cell could also be equipped with a lead cathode for nitrate destruction. As previously mentioned, non-conductive electrode spacers 23 provide the desired interelectrode gap or spacing between adjacent anodes and cathodes. The thickness of spacers 23 , which are non-conductive, insulative porous mesh screens fabricated from polymeric materials, such as polyolefins, like polypropylene and polyethylene, determines the width of the interelectrode gap. Alternatively, it is permissible to employ ionic polymer spacers which can effectively increase the ionic conductivity of the cell, so as to reduce cell voltage and operating costs further. Ion-exchange resins of suitable dimensions, like cation and anion exchange resin beads are held immobile within the gap between electrodes. For most applications, the interelectrode gap ranges from near zero gap, to avoid electrode shorting, to about 2 mm. More specifically, this very small capillary size gap is preferably less than a millimeter, ranging from 0.1 to <1.0 mm. The very small interelectrode gap makes possible the passage of current through relatively non-conductive media. This is the case, for example, in water contaminated with organic compounds. Thus, with the present invention it is now possible to destroy contaminants in solution without adding any current carrying inorganic salts to increase the ionic conductivity of the aqueous media. Furthermore, the very narrow interelectrode gap provides the important advantage of lower cell voltages which translates into reduced power consumption and lower operating costs. Hence, the combination of open configuration electrochemical cells and very narrow interelectrode gaps of this invention provide for both lower initial capital costs, as well as lower operating costs. This achievement is especially important in large volume applications, as in the purification of drinking water, and wastewater, according to the claimed processes. FIG. 2 represents a further embodiment of the electrochemical cells of this invention wherein the electrolyzer zone 30 is also in an open configuration. The electrolyte 32 is fed directly to the electrode stack 34 which is in a vertical orientation. As a result, treated aqueous solution 36 is shown exiting mainly from both the top and bottom peripheral edges of electrode stack 34 . This may be altered further depending on the use of baffles, for instance, in controlling residency time for the solution being treated. Purified solution is collected in vessel 38 below electrolyzer zone 30 . FIG. 3 represents still a: third embodiment of the invention wherein the electrolyzer zone 40 comprises an electrode stack 42 , as discussed above, positioned in the interior of an open housing/tank 44 . Housing 44 is open at the top allowing gaseous by-products of the electrolysis reaction, like hydrogen and oxygen, for instance, to be readily discharged into the atmosphere or collected through aid of an appropriate device, such as a hood (not shown). Aqueous contaminated electrolyte solution 46 is fed directly to electrode stack 42 positioned in open housing 44 , unlike other tank cells wherein the electrodes receive solution indirectly as a result of their immersion in the solution delivered to the tank. Purified water 48 cascading downwardly as a result of gravitational forces collects at the bottom of the interior of housing 44 , and is withdrawn. An important advantage of the open configuration electrochemical cells of this invention resides in their ability to be readily adaptable to either a monopolar or bipolar configuration. In this regard, FIG. 5 illustrates a monopolar open configuration electrochemical cell. In the monopolar cell of FIG. 5, anodes 52 , 54 and 56 each require an electrical connector as a current supply, in this case through a bus 58 as a common “external” supply line similarly, cathodes 60 and 62 each require an electrical connection shown through a common bus 64 . It is also characteristic of the monopolar cell design that both faces of each electrode are active, with the same polarity. Because water purification for a municipality, in general, is a large volume application, lowest possible cell voltages are essential in order to minimize power consumption. The open configuration, monopolar cell design of the present invention in combination with very narrow interelectrode gaps offers not only the benefits of lower initial capital costs, but also low operating costs, due to lower internal resistances, lower cell voltages and higher current densities. This combination is especially desirable when treating contaminated aqueous media of relatively low conductivity without the addition of inorganic salts as current carriers in accordance with certain embodiments of this invention, e.g., aqueous solutions contaminated with non-polar, organic solvents. The open configuration, monopolar, controlled leakage electrochemical cells with very narrow interelectrode gaps of this invention are particularly unique in light of the Beck et al cells of U.S. Pat. No. 4,048,047. The closed configuration of the electrochemical cells of Beck et al make it very difficult and costly to achieve a monopolar connection with high current densities associated with external electrical contacts to each electrode. By contrast, with the open configuration of the electrochemical cells of this invention electrical connections to individual electrodes are facilitated, irrespective of whether the cell is a monopolar or bipolar design. Thus, the closed, bipolar electrochemical cell configuration of Beck et al would not be economic and cost competitive with the improved electrochemical cells of the present invention, or with other non-electrochemical technologies used in high volume water purification processes. As previously indicated, the open configuration, controlled leakage electrochemical cells of this invention having very narrow capillary interelectrode gaps are also readily adaptable to bipolar configuration. FIG. 6 illustrates open configuration bipolar cell 70 , according to the present invention, requiring only two “external” electrical contacts 72 and 74 through two end electrodes/end plates 76 and 78 . Each of inner electrodes 80 , 82 and 84 of the bipolar cell has a different polarity on opposite sides. While the bipolar cell can be quite economic in effectively utilizing the same current in each cell of the electrode stack, one important aspect of the invention relates to treating solutions by passing a current through relatively non-conductive media using very narrow interelectrode gaps. That is, the contaminated aqueous solutions can have relatively low conductivities, about equivalent to that of tap water. In order to efficiently treat such solutions it would be desirable to operate at higher current densities. The monopolar cell configurations of the invention enable operating at desired low cell voltages and high current density. While not specifically illustrated, it will be understood standard power supplies are utilized in the electrolysis cells of the invention, including DC power supply, AC power supply, pulsed power supply and battery power supply. The invention also contemplates open configuration electrochemical cells with distributor means for contaminated aqueous electrolyte solutions, such as a length of pipe 81 with multiple openings or pores, or a feeder tube extending from the contaminated aqueous electrolyte feed inlet through the depth of the electrode stack in the electrolyzer zone. This can provide more uniform flow of solution to the electrode elements. Especially useful for stacks containing many electrode elements, these porous tubes of metal or plastic material, of sufficient porosity, diameter and length, are applicable to monopolar, bipolar, and for example, Swiss roll cells of open configuration. For deep cell stacks with electrode elements, each of larger surface area, more than one porous feeder tube may be provided, manifolded together with the feed inlet conduit. The open configuration, bipolar type, controlled leakage electrochemical cells of the present invention can be most effectively used in the purification of aqueous solutions possessing greater ionic conductivities than those previously discussed, allowing for economical operation at lower current densities. In each instance, the open configuration of the electrochemical cells of this invention facilitates their electrical connection, whether the cell is a monopolar or bipolar design. Most desirably, large volume applications like water purification require low capital and operating costs in order to be economically attractive. These inventors found that capital costs are largely reduced by eliminating the need for precision machined components, gasketing, costly membranes and cell separators. Lower operating costs can be achieved through lower cell voltages from narrow interelectrode gaps and lower IR from elimination of cell membranes and separators, i.e., undivided electrochemical cells. The smaller interelectrode gap, however, also makes possible the operation of the cells of this invention in an organic media, for example, containing low concentrations of supporting electrolyte, with a variety of electrode, insulator materials, and so on. Many of such applications would be readily adaptable to the open cell configuration of this invention, but with use of a cell divider forming anolyte and catholyte compartments, such as membranes or cell separators. Examples of useful processes for the electrochemical cells of this invention would include mediated reactions in electrochemical synthesis in which the objective of the membrane or separator would be to prevent reduction of anodically produced species at the cathode, and/or oxidation of cathodically produced species at the anode. FIG. 7 is a representative example of an open configuration electrochemical 90 having anode/end plates 92 and 94 with central cathode 96 and cation exchange membranes 98 and 100 positioned between the electrodes. Membranes 98 and 100 prevent mixing of the anolyte and catholyte in the cell while the solution is allowed to flow through opening 102 in the center of the membrane. Those embodiments of the electrochemical cells employing a diaphragm or separator are preferably equipped with ion-exchange membranes, although porous diaphragm type separators can be used. A broad range of inert materials are commercially available based on microporous thin films of polyethylene, polypropylene, polyvinylidene-difluoride, polyvinyl chloride, polytetrafluoro-ethylene (PTFE), polymer-asbestos blends and so on, are useful as porous diaphragms or separators. Useful cationic and anionic type permselective membranes are commercially available from many manufacturers and suppliers, including such companies as RAI Research Corp., Hauppauge, N.Y., under the trademark Raipore; E.I. DuPont, Tokuyama Soda, Asahi Glass, and others. Generally, those membranes which are fluorinated are most preferred because of their overall stability. An especially useful class of permselective ion exchange membranes are the perfluorosulfonic acid membranes, such as those available from E.I. DuPont under the Nafion® trademark. The present invention also contemplates membranes and electrodes formed into solid polymer electrolyte composites. That is, at least one of the electrodes, either anode or cathode or both anode and cathode, are bonded to the ion exchange membrane forming an integral component. In the purification of solutions the invention provides for the treatment of low conductivity media. However, it may be necessary to add very low concentrations of inert, soluble salts, such as alkali metal salts, e.g. sodium or potassium sulfate, chloride, phosphate, to name but a few. Stable quaternary ammonium salts may also be employed. As previously mentioned, ion exchange resin beads of appropriate size can be inserted in the spaces between the electrodes to increase conductivity. This will provide further reductions in cell voltage and total operating costs. Contaminated solutions entering the cell can range in temperature from near freezing to about boiling, and more specifically from about 40° to about 90° C. Higher temperatures can be beneficial in lowering cell voltages and increase rates of contaminant destruction. Such higher temperatures can be achieved, if needed, by preheating the incoming solution, or through IR heating in the cell, especially when solution conductivities are low, as for example in purification of drinking water. By suitably adjusting the cell voltage and residence time in the cell, beneficial temperatures in the above ranges are possible. As a preferred embodiment of the invention, as an undivided cell, for the purification of contaminated aqueous solutions a variety of useful anode and cathode species can be generated during electrolysis which in turn aid in the chemical destruction of contaminants and the purification of the aqueous solutions. They include such species as oxygen, ozone, hydrogen peroxide, hydroxyl radical, and other reactive oxygen species. Less preferred species, although useful in the process include the generation of chlorine or hypochlorite (bleach) through the electrolysis of brine or sea water. While not wishing to be held to any specific mechanism of action for the success of the processes in the decontamination, decolorization and sterilization of aqueous solutions contaminated with toxic organics and microorganisms, several processes, including those previously mentioned, may be occurring simultaneously. They include, but are not limited to the direct oxidation of contaminants at the anode; destruction of contaminants by direct reduction at the cathode; oxygenation of the feed stream by micro bubbles of oxygen produced at the anode; degasification of volatiles in the feed stream by oxygen and hydrogen micro bubbles; IR heating in the cell; aeration of the water stream exiting the open cell, and so on. A broad range of compounds, microorganisms and other hazardous substances as previously discussed are successfully destroyed in the open cell configuration of the invention employing the processes as described herein. Representative examples include aliphatic alcohols, phenols, nitrated or halogenated aromatic compounds, and so on. Color reduction or complete elimination of color can also be achieved, along with disinfection, including the destruction of viruses. The following specific examples demonstrate the various embodiments of the invention, however, it is to be understood they are for illustrative purposes only and do not purport to be wholly definitive as to conditions and scope. EXAMPLE I A monopolar electrochemical cell having an open configuration was set up with an electrode stack comprising 316 stainless steel end plates each with a diameter of 12.065 centimeters and a thickness of 0.95 centimeters. The end plates were connected as cathodes. A central cathode was also assembled into the stack and consisted of 316 stainless steel mesh with 7.8×7.8 openings/linear centimeter, 0.046 centimeter wire diameter, 0.081 centimeter opening width and 41 percent open area. The anodes consisted of two platinum clad niobium electrodes manufactured by Blake Vincent Metals Corp. of Rhode Island. The anodes which were clad on both sides of the niobium substrate had a thickness of 635 micrometers, were expanded into a mesh with a thickness of about 0.051 centimeters, with 0.159 centimeter diamond shaped interstices. The spacers positioned between adjacent electrodes were fabricated from polypropylene mesh with 8.27×8.27 openings/linear centimeter, 0.0398 centimeter thread diameter, 0.084 centimeter opening and a 46 percent open area was supplied by McMaster-Carr of Cleveland, Ohio. The gap between the electrodes was approximately 0.04 centimeters, determined by the thickness of the polypropylene mesh. A schematic of the electrochemical cell corresponds to FIG. 1 of the drawings, except a hood was omitted. Recirculation of the aqueous solution between the glass collection tank and the cell was effected by means of an AC-3C-MD March centrifugal pump at a flow rate of about 1 liter/minute. A Sorensen DCR 60-45B power supply was used to generate the necessary voltage drop across the cell. A test solution was prepared containing 1 g of phenol in 1 liter of tap water. The solution was recirculated through the cell while a constant current of 25 amps was passed. The solution which was initially clear turned red after about 2-3 minutes into the treatment process, possibly indicating the presence of quinone-type intermediates. The initial cell voltage of 35 V decreased rapidly to 8-9 V, and the temperature of the solution stabilized at about 56-58° C. Samples taken were analyzed periodically for total organic carbon (TOC). The results, which are shown in FIG. 8, appear to suggest the decrease in TOC is from the phenol probably undergoing complete oxidation to carbon dioxide which is then eliminated as gas from the solution. EXAMPLE II In order to demonstrate color reduction in a textile effluent 1 liter of solution was prepared with tap water containing 0.1 g of the textile dye Remazol™ Black B (Hoechst Celanese), 0.1 g of the surfactant Tergitol™ 15-S-5 (Union Carbide) and 1 g of NaCl. The composition of the test solution was similar to that of typical effluents produced in textile dyeing processes where even very low concentrations of Remazol Black impart very strong coloration to solutions. Remazol Black is a particularly difficult to treat textile dye. Heretofore, other methods used to treat Remazol Black, such as by ozonation or with hypochlorite bleach have failed to produce satisfactory color reduction. The above solution containing Remazol Black was electrolyzed in the monopolar cell set up of Example I above, at a constant current of 25 amps. The cell voltage was about 25 V, and the temperature of the solution reached 52° C. The initial color of the solution was dark blue. After 10 minutes of electrolysis the color of the solution turned to pink, and after 30 minutes the solution was virtually colorless. EXAMPLE III A further experiment was conducted in order to demonstrate the decontamination of ground water. Humic acids are typical contaminants of ground water, produced by the decomposition of vegetable matter. Water containing humic acids is strongly colored even at low concentrations, and the elimination of the color can be difficult. A dark brown solution in tap water was prepared containing 30 ppm of the sodium salt of humic acid (Aldrich) without any additives to increase the electrical conductivity of the solution. The solution was recirculated through a monopolar electrochemical cell similar to that used in Example I, but equipped with only one anode and two cathodes. A constant current of 10 amps was passed for 2.5 hours. The cell voltage was 24-25 volts, and the temperature reached 58° C. At the end of the experiment the solution was completely clear, demonstrating the effective destruction of humic acid. EXAMPLE IV A further experiment was conducted to demonstrate the effectiveness of the electrolysis cells and methods of this invention in the sterilization and chemical oxygen demand (COD) reduction in effluents from food processing plants. 250 ml of wastewater from a Mexican malt manufacturing company was treated using a monopolar, open electrochemical cell similar to that employed in Example I, except the total anode area of 6 cm 2 . The objectives were to reduce the COD, partial or total reduction of the color, elimination of microorganisms and odor. A current of 1 amp was passed for 150 minutes; the initial cell voltage of 22 V dropped to 17.5 V, and the temperature of the solution reached 44° C. The results are shown in the following Table: TABLE Initial Final COD 1700 ppm 27 ppm Color Yellow-Orange Clear Microorganisms Active Sterilized Odor Yes No EXAMPLE V A further experiment was conducted to demonstrate the effectiveness of the electrolysis cells and methods of this invention in the removal of color in a single-pass configuration. A dark purple solution containing methyl violet dye in tap water at a concentration of 15 ppm was circulated through a monopolar, open electrochemical cell similar to that employed in Example 1, in single-pass mode, at a flow rate of 250 ml/minute. The objective was to achieve total reduction of the color. A current of 25 amp was passed; the cell voltage was 25 V, and the temperature of the solution reached 65° C. After a single pass through the cell a clear solution was obtained. EXAMPLE VI An experiment can be conducted to demonstrate the utility of the open configuration electrochemical cell in the electrosynthesis of chemicals, in this instance sodium hypochlorite. The electrochemical cell of Example I is modified by replacing the anodes with catalytic chlorine evolving anodes, such as DSA® anodes manufactured by Eltech Systems. A solution of brine containing 10 g of sodium chloride per liter is introduced into the electrolyzer zone wherein chlorine is generated at the anode and sodium hydroxide is produced at the cathode. The chlorine and caustic soda are allowed to react in the cell to produce a dilute aqueous solution of sodium hypochlorite bleach. While the invention has been described in conjunction with various embodiments, they are illustrative only. Accordingly, many alternatives, modifications and variations will be apparent to persons skilled in the art in light of the foregoing going detailed description, and it is therefore intended to embrace all such alternatives and variations as to fall within the spirit and broad scope of the appended claims.	Electropurification of contaminated aqueous media, such as ground water and wastewater from industrial manufacturing facilities like paper mills, food processing plants and textile mills, is readily purified, decolorized and sterilized by improved, more economic open configuration electrolysis cell designs, which may be divided or undivided, allowing connection as monopolar or bipolar cells. When coupled with very narrow capillary gap electrodes more economic operation particular when treating solutions of relatively low conductivity is assured. The novel cell design is also useful in the electrosynthesis of chemicals, such as hypochlorite bleaches and other oxygenated species.	2
CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is the US National Stage of International Application No. PCT/EP2014/072703 filed Oct. 23, 2014, and claims the benefit thereof. The International Application claims the benefit of European Application No. EP13190849 filed Oct. 30, 2013. All of the applications are incorporated by reference herein in their entirety. FIELD OF INVENTION [0002] The present invention relates to a method for operating at partial load a gas turbine which comprises a compressor for providing compressor air, a combustion chamber provided with a burner, and an expansion turbine, a bypass flow channel furthermore being provided, which is configured in order to deliver compressor air past the burner and to a hot gas flow generated in the combustion chamber during gas turbine operation. The present invention also relates to such a gas turbine. BACKGROUND OF INVENTION [0003] Gas turbines can typically be operated only in a restricted way in their power range toward the lower partial load ranges because of limit value requirements for the CO emission quantities. This is because, when the partial load operation is reduced to lower powers, the primary zone temperature of the combustion typically decreases continuously. When this primary zone temperature falls below a temperature limit value typical of a gas turbine, the amount of CO emission increases, sometimes exponentially, since the combustion of CO to form CO 2 can no longer take place to a sufficient extent. When predetermined limit values are reached, the partial load operation must therefore be restricted to lower powers in order not to violate the CO emission limit values. Such a restriction likewise has an effect on the operation of a steam turbine system coupled to such a gas turbine (in the sense of a Combined Cycle Power Plant, CCPP), since a power reduction possibly desired by the operator is not to be reached below a limit value. [0004] Because of compliance with predetermined CO emission limit values, a power plant operator is thus obliged to periodically turn off the gas turbine, or a steam power plant system coupled to this gas turbine, or remain in a partial load range which lies above the technically possible minimum power. [0005] There is consequently a technical requirement to provide a gas turbine, or a method for operating such a gas turbine, making it possible to reduce the partial load range further without simultaneously exceeding CO emission limit values. In other words, the partial load range of the gas turbine is intended in particular to be extended downward while complying with CO emission limit values. Above all, this partial load range should be provided below the otherwise technically available load range which can be achieved by suitable guide vane adjustment (so-called guide vane adjustment range). [0006] One solution approach for these technical requirements may be specified by the publications US 2010/0175387 A1 and U.S. Pat. No. 5,537,864. In these documents, it is proposed to adjust the amount of air blown out from the compressor by suitable control by means of a bypass flow channel, in such a way that the primary zone temperature does not change substantially. Since the primary zone temperature itself cannot be measured directly, however, these controls always rely on predetermined assumptions, or estimates. [0007] At this point, it should be pointed out that the primary zone temperature (TPZ) is an average temperature determined from the energy balance around the burner and flame, which describes the thermodynamic state of the hot gas after completed chemical reaction. The TPZ therefore correlates with the proportion of CO in the combustion gases. [0008] It is therefore desirable to provide a more highly developed method which can avoid the above-mentioned problems of the prior art, and at the same time can provide reference quantities that can be metrologically recorded better. SUMMARY OF INVENTION [0009] Objects of the invention are achieved by a method as claimed , as described above and below, for operating such a gas turbine, and by a gas turbine as claimed as described below. [0010] In particular, these objects of the invention are achieved by a method for operating at partial load a gas turbine which comprises a compressor for providing compressor air, a combustion chamber provided with a burner, and an expansion turbine, a bypass flow channel furthermore being provided, which is configured in order to deliver compressor air past the burner and to a hot gas flow generated in the combustion chamber during gas turbine operation, and the opening cross section of the bypass flow channel furthermore being adjustable by a setting means, which comprises the following steps:—operating the gas turbine at partial load;—adjusting the opening cross section of the bypass flow channel so that the variation rate of the opening cross section is selected in such a way that the relative combustion chamber pressure loss or a material temperature of the combustion chamber is essentially constant, in particular that the relative combustion chamber pressure loss or the material temperature of the combustion chamber does not vary by more than 10%. [0011] Objects of the invention are furthermore achieved by a gas turbine suitable for carrying out a method as presented above and below, which comprises a compressor for providing compressor air, a combustion chamber provided with a burner, and an expansion turbine, a bypass flow channel furthermore being provided, which is configured in order to deliver compressor air past the burner and to a hot gas flow generated in the combustion chamber during gas turbine operation, and the opening cross section of the bypass flow channel furthermore being adjustable by a setting means, which furthermore comprises an adjustment unit, which is configured in order to adjust the opening cross section of the bypass flow channel in such a way that the variation rate of the opening cross section is selected in such a way that the relative combustion chamber pressure loss or a material temperature of the combustion chamber is essentially constant, in particular that the relative combustion chamber pressure loss does not vary by more than 10%. [0012] The adjustment unit is in this case advantageously configured as a regulating unit, although it may also be configured as a control unit. The adjustment unit in this case allows automatic adjustment of the variation rate of the opening cross section, or of the opening cross section. [0013] It should be pointed out that the relative combustion chamber pressure loss can be determined as the ratio of the combustion chamber differential pressure and the compressor final pressure. In this case, the combustion chamber differential pressure is given by a difference of two static pressures, which are determined at different measurement positions on or in the combustion chamber. Typically, one pressure determination is determined before the burner, or in the region of the burner, and one pressure value inside the combustion chamber, for instance at the end of the combustion zone. The pressure difference of the two pressure values determined is related by taking the ratio to the compressor final pressure, which, as the name already says, describes the static pressure at the end of the compressor and can likewise be recorded metrologically. [0014] It should likewise be pointed out that that the combustion chamber material temperature according to the invention relates to a material temperature which can be recorded metrologically directly or indirectly. Such a temperature is, in particular, a temperature of the combustion chamber wall, a temperature of the combustion chamber tiles, or for instance a temperature of a flame tube component which the combustion chamber also comprises. [0015] The provision of a bypass flow channel as described above in a gas turbine is already known from the prior art. For example, DE 43 39 724 C1 describes a gas fitting which has a common wall between a compressor outlet and a turbine outlet. This wall has a slider which covers corresponding slots in this wall. The slots are in this case to be understood in the sense of a bypass flow channel. The slots can be adjusted variably in terms of their opening cross section by actuating the slider. According to the teaching of DE 43 39 724 C1, provision is made to adjust the slots according to the gas turbine power, so as to keep the mass flow rate in the turbine at a suitable order of magnitude. In the event of load shedding, in order to avoid automatic acceleration of the gas turbine, the slots can be moved approximately immediately into a final position, for instance by suitable actuation, so as to avoid bypassing of the burner by the compressor air. The operating mode described in DE 43 39 724 C1, however, is intended exclusively for power regulation and therefore does not allow operation which is carried out in accordance with CO emission limit values. [0016] At this point, it should be pointed out that the disclosure of DE 43 39 724 C1 is incorporated into the present application by explicit reference. [0017] Adjustment of the opening cross section of the bypass flow channel can now ensure that an operating mode complying with CO emission limit values can be achieved in the event of partial load operation. In this case, for instance, the opening cross section of the bypass flow channel may be varied as a function of time so that the variation rate of the opening cross section is selected in such a way that the primary zone temperature is essentially constant. Advantageously, the primary zone temperature in this case remains essentially constant below the gas turbine power range determined by the guide vane adjustment range. When the minimum guide vane adjustment range is reached, the primary zone temperature thus typically still lies above a temperature below which a significant increase in the CO emission values is to be expected. Suitable estimates of this temperature are known from the prior art. [0018] On the basis of such thermal estimates, or suitable calculation methods, the opening cross section of the bypass flow channel can also be calculated in the event of partial load powers which lie in particular below the gas turbine power range determined by the guide vane adjustment range, in which case an essentially constant primary zone temperature may for instance be ensured as a boundary condition. Such estimates or calculation methods may sometimes also be based on test measurements. If partial load operation is now reduced to lower values, according to the invention a continuous adjustment of the opening cross section of the bypass flow channel to larger values is carried out, so that an increasing pressure equalization between the downstream region of the bypass flow channel (combustion chamber) and the upstream region of the bypass flow channel (compressor air plenum) results. [0019] As a consequence of this, the pressure difference which determines the flow rate of the compressor air through the burner is also reduced. At the same time—varying depending on the embodiment of the gas turbine—it is also possible to modify the cooling power for the combustion chamber cooling, which results for instance because of the flow of compressor air into cooling channels of the combustion chamber for cooling hot gas parts in the combustion chamber. At this point, the gas turbine of the type SGT X-200E of the Applicant is to be mentioned in particular, in which such cooling channels are provided as cooling air bores for cooling the flame tube bottoms by impact cooling (see also, for instance, DE 43 39 724 C1). [0020] Because of the reduction of the pressure of the compressor air flow delivered to the combustion chamber, there is also a reduction in the cooling power of the hot gas parts in the combustion chamber. If the thermal loads for the hot gas parts of the combustion chamber now become too great because of the reduced cooling, material damage and failure of individual components is to be expected. In order to anticipate such a development, it is now proposed according to the invention to carry out an adaptation of the variation rate of the opening cross section of the bypass flow channel, specifically in such a way that the relative combustion chamber pressure loss or a material temperature of the combustion chamber is used as an adjustment quantity. By an essentially constant relative combustion chamber pressure loss, the flow rate of the compressor air for cooling the hot gas parts in the combustion chamber is likewise kept essentially constant. This results in an essentially constant cooling rate, so that it is possible to avoid an increase of the temperatures to which the hot gas parts in the combustion chamber are exposed. [0021] According to one embodiment, it is proposed to operate a gas turbine by a method for operating the gas turbine at partial load with the following steps:—operating the gas turbine ( 100 ) at partial load;—adjusting the opening cross section (Q) of the bypass flow channel ( 10 ) so that the variation rate (V) of the opening cross section (Q) is selected in such a way that the primary zone temperature (TPZ) is essentially constant, and in particular does not vary by more than 10%. This is intended in particular to be carried out in the event of a reduction of the partial load, and specifically initially until the thermal loads for the hot gas parts of the combustion chamber become too great. Subsequently, provision may be made to operate the gas turbine by a method as claimed, so that the resulting cooling power in the combustion chamber, or at the hot gas parts in the combustion chamber, is essentially constant. According to this embodiment, the primary zone temperature is thus initially used as a suitable adjustment quantity, the relative combustion chamber pressure loss or the material temperature of the combustion chamber being used as a further adjustment quantity after reaching a temperature limit value not further to be exceeded. By the combined mode of operation, or the respective individual modes of operation, it is ensured that the CO emission values can be kept essentially constant, or lie below predetermined CO limit values. [0022] The variation rate of the opening cross section of the bypass flow channel is thus adapted in the course of the partial load operation in such a way that a reduction of the partial load below system-specific limit values (for instance determined by the guide vane adjustment range) can be made possible. [0023] According to the invention, it is possible to carry out the variation of the opening cross section of the bypass flow channel as a continuous and/or stepwise variation over time, the respective variations being carried out in such a way that the underlying adjustment quantities (for instance relative combustion chamber pressure loss) remain essentially constant, but in particular do not vary by more than 10%. The respective variations to be carried out may, in the case of a discrete variation, be stored in the scope of interpolation points in an adjustment unit, which then if need be cause a suitable variation of the opening cross section. The variation rate of the opening cross section is in this case to be understood as a time average over the individual discrete interpolation points. [0024] According to a first embodiment of the invention, a first method for operating the gas turbine at partial load with the following steps is carried out during a first time period:—operating the gas turbine ( 100 ) at partial load;—adjusting the opening cross section (Q) of the bypass flow channel ( 10 ) so that the variation rate (V) of the opening cross section (Q) is selected in such a way that the primary zone temperature (TPZ) is essentially constant, and in particular does not vary by more than 10%. The method as claimed is carried out during a second time period, in particular with the second time period directly following the first time period. As already explained above in detail, in this way it is possible to achieve a particularly efficient operating mode of the gas turbine at partial load, which allows CO-compliant operation even in very low partial load ranges. According to one embodiment, it is particularly advantageous for the partial load to be reduced in this case over the time periods, and in particular reduced over the two time periods. [0025] According to another embodiment of the method according to the invention, the method for operating the gas turbine at partial load with the following steps:—operating the gas turbine ( 100 ) at partial load;—adjusting the opening cross section (Q) of the bypass flow channel ( 10 ) so that the variation rate (V) of the opening cross section (Q) is selected in such a way that the primary zone temperature (TPZ) is essentially constant, and in particular does not vary by more than 10%, is carried out during a first time period until a first thermal characteristic reaches a predetermined first limit value, in particular with this being followed by a second time period during which a method as claimed is carried out. The first thermal characteristic is in this case, in particular, a measure of the cooling power at hot gas parts of the combustion chamber. To this extent, when a thermal limit value (first limit value) is exceeded, more reliable operation of the gas turbine is achieved even with still low partial load powers than during the first time period, without exceeding CO emission limit values. [0026] According to another method, the method as claimed is carried out with a partial load reduction until a second thermal characteristic reaches a predetermined second limit value, in particular with the variation of the opening cross section then being selected in such a way that the opening cross section is reduced, in particular reduced stepwise. Such a method-technology precaution may sometimes be necessary since the relative combustion chamber pressure loss is dependent on the ambient conditions, and a sufficient cooling power of the hot gas parts of the combustion chamber cannot therefore always be ensured, for instance when the ambient temperatures are very high. If a sufficient cooling power is not then provided despite a continuous or stepwise increase of the opening cross section of the bypass flow channel, a second limit value of a second thermal characteristic may be exceeded. The thermal characteristic is in particular a suitable adjustment quantity which records the thermal loading the combustion chamber, and therefore ensures thermally reliable operation of the gas turbine. A suitable characteristic quantity for this thermal load may, for example, be a measured material temperature (advantageously in the combustion chamber), which has been recorded directly or indirectly by means of a thermocouple, or a substitute characteristic, for example the relative combustion chamber pressure loss or another suitable thermal quantity. [0027] If the second limit value is now reached by the second thermal characteristic, the opening cross section of the bypass flow channel is reduced. This reduction is advantageously carried out in steps of about 10% of the overall range. As a result of this, the cooling air flow rate increases again and the hot gas parts of the combustion chamber are supplied with more cooling power. According to one embodiment, this process with a stepwise variation may in particular be repeated until the second thermal characteristic reaches a value above a further third thermal limit value. [0028] According to one refinement of the method according to this embodiment, in the event of a reduction of the opening cross section and when a third thermal predetermined limit value is reached by the second thermal characteristic, the variation of the opening cross section is selected in such a way that the opening cross section is increased again, in particular increased again stepwise. A stepwise increase may in this case advantageously be carried out in steps of about 10% of the overall range. Owing to the hysteresis thus carried out of initially a reduction and then subsequently an increase of the opening cross section of the bypass flow channel again, stable regulation of the gas turbine operation can be achieved. [0029] According to one embodiment of the method according to the invention, the method is carried out below the guide vane adjustment range. As a result of this, as explained above, the partial load power range can be reduced further, but without the risk of exceeding CO limit values. In this way, the flexibilizaton of the gas turbine operation can be improved significantly. [0030] According to a first embodiment of the gas turbine according to the invention, it furthermore comprises a regulating circuit and a measurement probe, the measurement probe being configured in order to record a thermal characteristic and the regulating circuit being configured in order, in the event of a partial load reduction and when a predetermined limit value (second limit value) of the thermal characteristic (second thermal characteristic) is reached, the variation of the opening cross section is selected in such a way that the opening cross section is reduced again, in particular reduced stepwise. [0031] As already mentioned above, stable regulation of the gas turbine can be achieved in this way, and at the same time the dependency of the relative combustion chamber pressure loss on the ambient conditions can be taken into account. Likewise, protection of hot gas parts of the combustion chamber by sufficient cooling can be ensured at the same time. [0032] According to another embodiment of the gas turbine according to the invention, the gas turbine is configured in such a way that the compressor air delivered to the burner is provided at least partially in order to cool hot gas parts of the combustion chamber, in particular flame tube bottoms, by means of feeding through cooling channels in the combustion chamber. By the provision of cooling channels in the combustion chamber, particularly when carrying out the method as claimed, a sufficient cooling power can be ensured. Overheating and consequent damage to hot parts of the combustion chamber can therefore be prevented. [0033] The invention will be described in detail below with the aid of individual figures. In this case, technical features which have the same references have the same technical effects. [0034] It should likewise be pointed out that the following figures are to be interpreted merely schematically, and no restriction in respect of the implementability of the invention may be based thereon. [0035] It should likewise be pointed out that the technical features explained below are claimed in any combination with one another so long as the combination can achieve the object of the invention. BRIEF DESCRIPTION OF THE DRAWINGS [0036] FIG. 1 shows a schematic representation of the variation of the primary zone temperature (TPZ) as a function of the relative gas turbine power (AGTP) with a fully closed and open opening cross section of the bypass flow channel; [0037] FIG. 2 shows a diagrammatic representation of the relative opening cross section (RQ) as a function of the corrected turbine output temperature (OTC) below the guide vane adjustment range (LSVB) corresponding to suitable embodiments of the operating mode according to the invention at partial load; [0038] FIG. 3 shows a functional profile of the second thermal characteristic (TK 2 ) as a function of time (t) during operation to reduce the partial load power when reaching a second limit value (GW 2 ) and a third limit value (GW 3 ); [0039] FIG. 4 shows an embodiment of the method according to the invention as claimed in a flowchart representation; [0040] FIG. 5 shows an embodiment of a gas turbine according to the invention in perspective lateral sectional view; [0041] FIG. 6 shows a simplified schematic partial sectional view of the gas turbine shown in FIG. 5 . DETAILED DESCRIPTION OF INVENTION [0042] FIG. 1 shows a diagrammatic representation of the profile of the primary zone temperature TPZ (in ° C.) as a function of the relative gas turbine power AGTP (in %). In this case, two fundamentally different modes of operation of the gas turbine are represented, namely one with a fully closed bypass flow channel (operating mode 200 ) and one with a fully open bypass flow channel (operating mode 210 ). A flatter profile in the region of the guide vane adjustment range LSVB over which the gas turbine can be operated with conventional partial load operation by suitable adjustment of the guide vanes in the guide vane adjustment range LSVB at different partial load powers, can be seen clearly for the two operating modes 200 and 210 . Support of the partial load operation below this guide vane adjustment range LSVB by adjusting the guide vanes is, however, no longer possible. The ranges available to the invention preferably relate to these ranges lying below. They consequently lie between the range 200 with a closed bypass flow channel and the range 210 which represents an operating mode with an open bypass flow channel. [0043] For example, FIG. 1 represents two points 220 , 230 which are used to illustrate further operating points. The operating point 220 represents an operating state with a minimum guide vane guide vane adjustment range, which, with a partially open bypass flow channel, reaches the primary zone temperature TPZ as exists for instance with a basic load. In contrast thereto, the operating point 230 represents an operating state which likewise reaches the primary zone temperature TPZ for a basic load, but does so with a fully open bypass flow channel. The operating point 230 is, however, significantly below the technically possible minimum guide vane adjustment range LSVB in terms of the relative gas turbine power. [0044] FIG. 2 represents the functional profile of the relative opening cross section RQ as a function of the corrected turbine output temperature OTC. The relative opening cross section RQ relates to the ratio of the existing, i.e. adjusted, opening cross section Q to the maximum possible opening cross section. In this case, the operating mode represented has, below the guide vane adjustment range LSVB, a control curve which has a plurality of interpolation points. With a decreasing corrected turbine output pressure OTC, i.e. with a decreasing partial load power, during a first time period ZA 1 an operating mode is initially selected which requires the adjustment of the opening cross section Q of the bypass flow channel 10 to be carried out in such a way that the variation rate V of the opening cross section Q is selected so that the primary zone temperature TPZ is essentially constant, and in particular does not vary by more than 10%. During this first time period ZA 1 , an essentially constant primary zone temperature TPZ can therefore be ensured, so that the CO emission values can be kept above particular limit values not to be exceeded. [0045] During a second time period ZA 2 , which directly follows the first time period ZA 1 , the operating mode is modified in such a way that it is now carried out according to an embodiment as claimed. In this case, for the gas turbine, the adjustment of the opening cross section Q of the bypass flow channel 10 is carried out in such a way that the variation rate V of the opening cross section Q is selected so that the relative combustion chamber pressure loss ABDV or the material temperature MT of the combustion chamber 4 is essentially constant, and in particular so that the relative combustion chamber pressure loss ABDV or the material temperature MT does not vary by more than 10%. According to this operating mode, it is possible to ensure that a sufficient cooling power for hot gas parts in the combustion chamber is still available, and thermal damage to these components can thus be prevented, while complying with the CO emission limit values. [0046] The further interpolation points, or operating states, shown in the representation respectively relate to interpolation points, or operating states, respectively known from the prior art, and not to be explained further. [0047] The corrected turbine output temperature OTC given in FIG. 2 corresponds to the turbine output temperature corrected in relation to the air temperature, as is explained in detail for example in EP 1 462 633 A1. [0048] FIG. 3 shows a variation, carried out in the event of partial load reduction, of the second thermal characteristic TK 2 as a function of time. In this case, it is shown that initially at small times the partial load reduction also entails a reduction of the second thermal characteristic TK 2 . When a predetermined second limit value GW 2 is exceeded, however, the variation of the cross section Q of the bypass flow channel 10 is selected in such a way that the opening cross section Q is now reduced, in particular reduced stepwise. The stepwise reduction is in this case indicated by the variation profile AQ of the opening cross section Q. Thus, a reduction of the opening cross section Q by two steps is initially carried out, so that the profile of the thermal characteristic TK 2 is again raised above the second limit value GW 2 . After two stepwise reductions of the opening cross section Q, the profile of the second thermal characteristic TW 2 reaches a third predetermined limit value GW 3 , which now requires the opening cross section Q to be increased again, in particular increased again stepwise. In the present case, the increase of the opening cross section Q again takes place in two steps of comparable size to the previous two steps, so that the resulting opening cross section Q corresponds to the opening cross section Q which there was before initiation of the stepwise variations. This leads to a stabilization of the strongly decreasing thermal characteristic and therefore a stabilization of the operation of the gas turbine 100 at partial load. The variations of the opening cross section Q according to the variation profile AQ are in this case carried out by an adjustment unit 20 , which instigates the corresponding adaptations. [0049] FIG. 4 shows an embodiment of the method according to the invention as claimed, which comprises the following steps:—operating the gas turbine 100 at partial load (first method step 400 );—adjusting the opening cross section Q of the bypass flow channel 10 so that the variation rate V of the opening cross section Q is selected in such a way that the relative combustion chamber pressure loss ABDV or the material temperature MT of the combustion chamber 4 is essentially constant, in particular that the relative combustion chamber pressure loss ABDV or the material temperature MT of the combustion chamber 4 does not vary by more than 10% (second method step 410 ). [0050] FIG. 5 shows a perspective partial sectional view through a gas turbine 100 according to the invention, which essentially corresponds to the model SGT5-2000E sold by the Applicant. Besides a compressor 1 and an expansion turbine 5 , the gas turbine 100 in this case comprises a combustion chamber 4 provided with a plurality of burners 3 . During operation of the gas turbine 100 , compressor air 2 is delivered laterally from the compressor 1 on the outside of the combustion chamber 4 to the burners 3 . Because of the static pressure difference between the combustion chamber 4 and the pressure of the compressor air 2 fed to the outside of the combustion chamber 4 , cooling air taken from this compressor air 2 flows through cooling channels 7 into the combustion chamber 4 . The rest of the compressor air 2 is then fed to the burners 3 and burnt with a suitable fuel. The combustion products are discharged from the combustion chamber 4 as a hot gas flow 6 and fed to the expansion turbine 5 to perform mechanical work. [0051] The gas turbine 100 represented has a bypass flow channel 10 (not further shown in detail), which is configured in order, during operation of the gas turbine 100 , to deliver compressor air 2 past the burner 3 and to a hot gas flow 6 generated in the combustion chamber 4 , in which case the opening cross section Q of the bypass flow channel 10 can furthermore be adjusted by a setting means 11 . This setting means 11 is also not shown in detail here. [0052] FIG. 6 shows a schematic side view through the embodiment of the gas turbine 100 as shown in FIG. 5 , which represents both the bypass flow channel 10 and the setting means 11 for adjusting the opening cross section Q of the bypass flow channel 10 . During operation of the gas turbine 100 , compressor air 2 is initially delivered from a compressor 1 (not further shown) to the combustion chamber 4 . The compressor air 2 is in this case fed to the burners 3 through a volume between the combustion chamber 4 and an outer wall 8 . In this case, the compressor air 2 flows past the bypass flow channel 10 , which has an opening cross section Q and fluidically connects the region between the combustion chamber 4 and the outer wall 8 to the combustion chamber 4 itself. The opening cross section Q can be adjusted by a slider configured as a setting means 11 (more detailed remarks about this technology may be found in DE 43 39 724 C1). The flow of the compressor air 2 is consequently divided at the opening cross section Q, one part flowing further to the burners 3 of the combustion chamber 4 , but another part flowing through the opening cross section Q into the combustion chamber 4 for pressure equalization. [0053] The flow of compressor air 2 fed to the burners 3 is furthermore reduced in that a part of this compressor air 2 can flow through cooling channels 7 (not further shown) into the combustion chamber 4 and in this case cool hot gas components (not further shown), in particular flame tube bottoms, of the combustion chamber 4 . The cooling power is in this case proportional to the static pressure difference existing at the cooling channels. [0054] The gas turbine 100 furthermore has an adjustment unit 20 , which comprises a regulating circuit 30 that is configured for suitable adjustment of the opening cross section Q of the bypass flow channel 10 . The gas turbine 100 likewise has a measurement probe 40 , which records a thermal characteristic (for example the turbine output temperature) and communicates the measurement value to the adjustment unit 20 , or the regulating circuit 30 . The gas turbine 100 likewise has a second measurement probe 50 arranged in the combustion chamber 4 , which is configured in order to metrologically record the material temperature MT of the combustion chamber 4 and to communicate the measurement value to the adjustment unit 20 , or the regulating circuit 30 . The adjustment unit 20 ensures that the opening cross section Q of the bypass flow channel 10 is adjusted in such a way that the variation rate V of the opening cross section Q is selected so that the primary zone temperature TPZ is essentially constant, and in particular does not vary by more than 10%, or that the variation rate V of the opening cross section Q is selected so that the relative combustion chamber pressure loss ABDV of the material temperature MT of the combustion chamber 4 is essentially constant, in particular so that the material temperature MT of the combustion chamber 4 does not vary by more than 10%. [0055] Further embodiments may be found in the dependent claims.	A gas turbine has a compressor providing compressed air, a combustion chamber provided with a burner, and an expansion turbine, wherein a bypass flow channel is also provided designed to supply compressed air past the burner and to supply a hot gas flow generated in the combustion chamber during operation of the gas turbine. The opening cross section of the bypass flow channel can be adjusted, and an adjustment unit is designed to adjust the opening cross section of the bypass flow channel such that the modification speed of the opening cross section is selected such that the relative combustion chamber pressure drop or a material temperature of the combustion chamber is substantially constant, in particular that the relative combustion chamber pressure drop or the material temperature of the combustion chamber does not vary by more than 10%.	8
FIELD OF THE INVENTION The present invention relates to data compression and particularly relates to a data compression method for voice data that may be efficiently utilized on a small computer. BACKGROUND AND SUMMARY OF INVENTION One purpose of the present invention is to enable small children in the age range of about 3-7 to communicate and interact with a computer under a substantially nonstructured format. The child is not given detailed instructions on using the computer but, instead, he or she is allowed to explore and discover how to operate it. For a young child to receive an appropriate level of feedback from the computer, the computer should talk to the child and provide it with spoken feedback as well as the usual visual output of the computer. The types of computers that are typically available to small children are small computers with limited memory. Thus, in order to store the needed voice responses in a small computer memory, a simple and efficient voice compression method is needed. For this particular application, so long as the quality of the voice reproduction is good, the primary consideration for this application is efficient processing and utilization of a minimum amount of memory for storing both the program and the data. The present invention takes advantage of the smooth transitions and repetitive nature of most speech. The rate of change of most speech is relatively slow so that when it is sampled at a frequency of 10,000 samples per second, the difference jumps between each of the samples are relatively small. In most cases, the voice data may be sampled and desensitized until the majority of the jumps have an absolute value of two or less, and yet the quality of the data will remain sufficiently high so that the voice may be reconstructed and easily understood by a child. By measuring and storing the jumps between data points, the voice may be compressed. In the preferred embodiment, a single byte is used to store three jumps by calculating a single compression number from the three jumps. In the decompression mode, the single compression number is used to reconstruct the value of the three jumps and they are used to reconstruct the voice. In order for a single compression number to represent three jumps, each jump must be within a set range. In a group of three, if one or two jumps falls outside the range, the compression number when decoded (decompressed) will reflect which of the jumps were out of range. The values of these jumps are then stored immediately after the compression number in the compressed data. If all three jumps in a group fall outside a first selected range but within a second selected range, a special code number is stored to indicate this fact, but instead of storing three numbers after the code number which would reflect the actual value of the three jumps, a two byte compression word is stored after the compression number. This compression word requires two bytes, but jumps outside of the first selected range may be coded into this word. For example, compression numbers can identify three jumps that fall within a range of +2 to -2, while a compression word can identify three jumps that fall within a range of +22 to +3 and -3 to -22. The range of +2 to -2 is not identified by the compression words since this range is covered by compression numbers. After compression, using compression numbers and compression words, the compressed data is again compressed by looking for periods of time in which there was no change in the voice signal. In such cases, the jumps would equal zero and a compression number of "56 H" (H indicates hexadecimal) would indicate three zero jumps. If two or more compression numbers of "56 H" are found, they are replaced by the code value "DA H" to indicate the repetition of the number "56 H" and data following "DA H" would indicate how many compression numbers of a value "56 H" were found in the compressed data string. BRIEF DESCRIPTION OF THE DRAWINGS The attached Figures are briefly described as follows: FIG. 1 is a block diagram of a computer system for receiving and transmitting voice data in which the computer stores the data in compressed form; FIG. 2 is a chart showing a signal being sampled by an A/D converter; FIG. 3 is a table showing the samples taken from the signal shown in FIG. 2 and illustrating compression of the data; FIG. 4 is a table showing another set of sample data and illustrating an alternate compression scheme; FIG. 5 is a table illustrating a second compression occurring after the first compression; and FIG. 6 is a flow chart illustrating the operation of one embodiment of the method of the present invention. DETAILED DESCRIPTION In accordance with the method of the present invention, in order to compress and store a voice signal, it is first sampled at a frequency of 10,000 times per second and the amplitude of each sample is recorded as an 8-bit number. This string of digital numbers then represents the voice data and to play back the voice, the digital numbers are converted back to an analog signal. FIG. 1 illustrates a computer system 10 that includes a microphone 12 that transmits voice data to an analog to digital converter 14 and then to computer 16. The computer 16 also transmits recorded voice data through digital to analog converter 18 and amplifier 20 to a speaker 22. The computer system 10 is well known in the art and the choice of computer system used to implement the invention is not considered to be a part of the invention. Those skilled in the art will also be familiar with how to input, store, transfer, manipulate and output data with a computer. These details are considered well known and are not set forth herein. Once the digital numbers are determined, compression begins. The first step of the compression method is to desensitize the data. This is done by dividing all of the numbers by some power of two, usually the second or first power. The amount of decompression is chosen so that most of the samples create jumps within a range of +2 to -2 from adjacent samples and, usually, the second or first power of two is sufficient to achieve the desired amount of decompression. The value of the first number in the digital voice data string is stored in the compressed data to provide a beginning point, and the difference between the first number and the second number is measured. A code is normally assigned to this "jump" between the first and second numbers, and, then, the next two jumps are determined by measuring the difference between the second and third number and between the third and fourth number, respectively. If any one of these three jumps is within the range of +2 to -2, a first compression option is performed in the following manner. If the first jump is "-2", a code "0" is assigned. If the jump is "-1", the code is "1". If the jump is "0", the code is "2". If the jump is "+1", the code is "3", and if the jump is "2", the code is "4". For any jumps of less than negative two or greater than plus two, the jump is assigned a code value of "5". After three successive jumps and codes are determined, a formula is used to develop a single number (herein referred to as a compression number or a compression byte) which can be used to determine the identity of the three codes. The formula is as follows: Compressed byte=[(6×Code 3+Code 2)×6]+Code 1. FIGS. 2 and 3 illustrates the sampling and compression described above. FIG. 2 is a graph of a signal, such as a voice analog signal, that is sampled 19 times. FIG. 3, column 2, shows the samples as a binary number and column 3 shows the jumps between samples. Column 4 shows the codes assigned to the samples and then Columns 5 and 6 show the compressed bytes that are generated from the codes. Columns 5 and 6 are identical except Column 5 shows hexadecimal numbers (base 16) and column 6 shows base 10 numbers. In order to decompress the compressed byte and determine from the compressed byte what the original three codes are, the compressed byte is first divided by six. The division will produce a quotient plus a remainder, and the remainder will be code 1. The whole number quotient that is found by the first division (without the remainder) is divided again by six which will result in a second whole quotient plus a remainder. The second remainder will be code 2. The second whole quotient is code 3. Thus, the decompression will produce all three original codes. In the discussion above, there is an explanation of how codes are generated from jumps, how a compressed byte is generated from three codes, and how the compressed byte is decompressed to regenerate the three codes. It will be appreciated that if all three codes were less than five, then the compressed byte contains all of the information necessary to regenerate the original jumps and the original signal. That is, since the value of the first digital number is stored and since all three codes may be determined from the compressed byte, the value of the first three numbers in the original digital voice data string may be determined by first determining the value of the three jumps corresponding to the three codes and adding these jumps to the first number in the compressed data to determine the next three numbers in the data string. All successive numbers in the digital voice data could be determined in the same manner provided all jumps are within the range of +2 to -2 meaning that no code 5's are encountered. However, if any of the codes are five, more information will be needed in order to determine the value of the original number in the digital voice data. Thus, in accordance with the first compression option of the present invention, if one or more of the three codes is "five" the actual value of the jump associated with the particular code five is stored immediately behind the compressed byte. When decompression is performed and a compressed byte is determined to include a "code five", it is known that the next number in the compressed data will represent the actual value of the jump corresponding to the particular code five position. If two of the codes are "five" it will be known that the next two numbers in the compressed data represent the actual value of the two jumps corresponding to the code fives, and if all three of the codes are "five", it will be known that the next three numbers correspond to the actual values of all three jumps of the group. These actual values of jumps are stored behind the compressed byte in the same order as the code. For example, if code 1 and code 3 have a value of "five", then the actual value of these two jumps will be stored in the same order (1 then 3) after the compressed byte so that the next number will correspond to code 1 and the following number will correspond to code 3. From the discussion above, it will be appreciated that if all three codes were "five" then the first compression option will actually result in an expansion of the data rather than a compression of the data. In other words, if all three codes are "five" this first compression option will replace three bytes in the digital voice data with four bytes in the compressed data. In one embodiment, this expansion is simply tolerated since it occurs infrequently, but in another embodiment, a second compression option is used to eliminate the expansion. In accordance with this latter embodiment, when three jumps of a group are outside of the range of +2 to -2, the digital voice data is checked to see if all three of the jumps are between +22 and 22. If they are, the code value of "DA H" (H means hexadecimal) is stored in the compressed data to indicate that the next two bytes represent a sixteen bit word which is coded with the formula: Compressed word=[(40×Code 3+Code 2)×40]+Code 1. Each of the three codes above are determined using the formula: Code=Data+17 for positive data. Code=Data+22 for negative data. When it is desired to decompress the compressed data created by the second compression option, the number "DA H" indicates that the compression was achieved by the second compression option using a multiplier of forty and that the next two bytes represent a sixteen bit word. That word is divided by forty and the remainder of the division is recognized as code 1. The whole quotient of the first division is divided by forty again, and the second remainder of the second division is recognized as code 2 while this second whole quotient derived from the second division is recognized as code 3. If the code value is nineteen or less, twenty-two is subtracted from the code value to determine the jump value. If the code value is twenty or more, seventeen is subtracted from the code value to determine the jump value. If any one of the three jumps in a group falls outside the range of +22 to -22, the first compression option is used and the resultant expansion is tolerated since it occurs very infrequently. FIG. 4 illustrates ten samples and compression by both options described above. Samples 2, 3 and 4 are compressed according to the first described option and samples 5, 6 and 7 are compressed using the second described option. Samples 8, 9 and 10 are compressed using the first option. After all of the digital voice data has been converted to compressed data as described above, another compression is performed. The data is scanned looking for a byte having the number "56 H". "56 H" is the number that will be generated by the first compression option when all of the codes are "two" indicating that all jump values were "zero". If two "56 H's" are found, the first one is replaced with "D8 H" and a count is begun of the number of "56 H's". This count is placed in the byte following "D8 H". If the count is less than "FF H", the grouping is finished and the remainder of the compressed data is scanned for "56 H's". However, if the count is more than "FF H", the byte after "D8 H" is filled with "FF H" and the count is continued. The bytes following "D8 H" are repetitively filled with "FF H" as is necessary to indicate the correct number of repetitive "56 H's". After a string of "FF H's", the next following byte will indicate the last number in a count of "56 H's". For example, during decompression, when a "D8 H" is encountered, and a "FF H" follows "D8 H", it is known that the number of "56 H's" is greater than "FF H" and the next byte will indicate the number of "56 H's" in excess of "FF H" that are encountered in the original compressed data. If another "FF H" is encountered, it is known that the number of "56 H's" was greater than "FF H" plus "FF H" and so on until the number of "56 H's" has been determined. For example, if 514 bytes have a value of "56 H" in a row, the codes which would appear in the compressed data are as follows: "D8 H", "FF H", "FF H", "04 H", [next code]. FIG. 5 illustrates this second compression. Four 56 H numbers were crested during the first compression as shown in column 1, and these four numbers are replaced with D8 H and 04 H as shown in column 2. FIG. 6 is a flow chart illustrating an embodiment of the invention selectively utilizing three compression options as described above In the discussion above, after each major compression step was explained, the corresponding decompression method was also discussed. This order was chosen to facilitate understanding of the compression method, but it will be understood, however, that all compression steps take place before any decompression is performed, and the overall preferred method of the invention may be summarized as stated below. The analog voice data is converted to digital voice data and is desensitized. The first number of the digital voice data is stored and the jumps between all remaining numbers in the digital voice data are determined. The data is analyzed in groups of three and, in a group of three jumps, if any one jump falls within the range of +2 to -2 or if any one of the three jumps are outside of the range of +22 to -22, the first compression option is used to generate codes, compression bytes and compression data. If all three jumps are outside the range +2 to -2 but within the range of +22 to -22, the second compression option is performed to determine the codes and a compressed word. After all of the digital voice data has been operated on by the first or second compression options, the compressed data is further compressed by substituting repetitive "56 H's", which indicate that all three jumps in a group are "zero", with the number "D8 H" followed by data indicating the number of times that "56 H" has been repeated in the original compressed data. To decompress, it is recognized that the first number in the compressed data represents the magnitude of the first sample of the voice data, and this magnitude value provides a starting place. If the next number encountered in the compressed data is less than "D8 H", then the data has been compressed using the first compression option, and it will be decompressed accordingly. If a "D8 H" is encountered at a position where a compressed byte would normally appear, the numbers following "D8 H" are known to indicate the number of times "56 H" has been encountered in the compressed data and, thus, indicates the number of zero jumps in the voice data. If the number "DA H" is encountered at a position where a compression byte would normally appear, it is known that the data has been compressed using the second compression option, and it is decompressed accordingly. In another embodiment of the invention, it may be desired to eliminate the second compression option, and in such case the first compression option is always used even when it results in expansion rather than compression. When decompressing, the same method as described above is used except that all decompression is conducted as described with respect to the first compression option. Since the second compression option is not used, the number "DA H" will never be encountered. Although the above two described embodiments are preferred, it will be understood that the invention is capable of modifications and substitutions without departing from the scope of the invention as defined by the appended claims.	A method for compressing and decompressing voice data enables efficient voice storage on small computers. Analog voice data is converted to digital voice data and the difference jumps between adjacent numbers in the digital voice data are measured. In the preferred embodiment, if the value of the jump is within the range +2 to -2, then a code value is assigned to that jump from zero to four where the code value equals the jump value plus two. If the jump value is outside the range, a jump is normally assigned a code value of five. Three adjacent codes are compressed to one code using the formula: Compression number=6×[6×(code 3)+ code 2] +code 1 and at least this compression number is stored. If one or two of the code values in a group of three code values has a value of five, the actual jump value is stored after the compression number. However, if all jumps in a group of three have an absolute value of greater than two and less than twenty-three, then a second compression option is chosen in which a compression word is generated that will identify the three jump values, and the compression word is stored as part of the compressed data. After the aforementioned compression steps, further compression is performed to eliminate repetitious zeroed jumps. Decompression is accomplished by reading the compressed data, recognizing the compression numbers and compression words and determining the codes and jumps from the compression numbers, the compression words, and the compressed data itself.	7
BACKGROUND [0001] This disclosure relates to additive manufacturing of aluminum articles. [0002] Additive manufacturing technologies have been used and proposed for use for fabricating various types of articles from various types of materials. Broadly viewed, additive manufacturing can include any manufacturing process that incrementally adds material to an assembly during fabrication, and has been around in one form or another for many years. Modern additive manufacturing techniques, however, have been blended with three-dimensional computer imaging and modeling in various types to produce shapes and physical features on articles that are not readily produced with conventional molding, shaping, or machining techniques. Such techniques were initially developed using polymer compositions that are fusible or polymerizable in response to a controllable source of light or radiation such as a laser. Three-dimensional articles can be fabricated a layer at a time based on data from a corresponding layer of a three-dimensional computer model, which are generally as stereolithography. With these techniques, a polymer powder or polymerizable liquid polymer composition is exposed to a source of energy such as a laser to fuse a thermoplastic polymer powder by heating it to a fluid state or by initiating a reaction between components in a powder or polymerizable liquid composition. The powder or liquid can be applied a layer at a time by any known mechanism such as by spray or other application, but is often maintained in a bed where the article being fabricated is formed. After each layer is fused and solidified, the article is lowered in the bed or the level of the bed is raised so that a layer of powder or liquid covers the previously-formed layer of the article, and another layer of the powder or liquid is fused and solidified by selective exposure to the energy source based on data from another corresponding layer of the computer model. [0003] Additive manufacturing techniques have also been used for the fabrication of metal articles. Metal thermal spray and other additive manufacturing techniques for metals have of course been known for some time. The application of stereolithographic manufacturing techniques to metals has led to significant advancements in the fabrication of three-dimensional metal articles. Using such techniques, a metal article being manufactured is maintained in a bed of metal powder, with the surface of the article below the surface of the powder in the bed so that there is a layer of metal powder over the surface of the article. Metal powder in this layer is selectively fused such as by selective exposure to an energy source such as a laser or electron beam, according to data from a corresponding layer of a three-dimensional computer model of the article. After each layer is fused and solidified, the article is lowered in the bed or the level of the bed is raised so that a layer of metal powder covers the previously-formed layer of the article, and another layer of the powder is fused and solidified by selective exposure to the energy source based on data from another corresponding layer of the computer model. The resulting can be relatively complex, compared to structures obtainable by conventional metal fabrication techniques such as casting, forging, and mechanical deformation. [0004] Attempts to fabricate aluminum and aluminum alloy articles using additive manufacturing techniques have met with limited success. Aluminum alloys used for casting have been proposed or tried for powder casting or additive manufacturing. However, many such alloys have limitations on strength or other physical properties that renders them unsuitable for many applications, including but not limited to aerospace and other applications requiring strength. For example, the alloy AlSi10Mg has been evaluated for additive manufacturing, but exhibits poor ductility and fracture toughness. High-strength aluminum alloys are also known. For example aluminum alloys 6061 and 7075 are well-known for their high strength in wrought aluminum articles. However, articles formed from these alloys using additive manufacturing techniques are susceptible to crack formation. BRIEF DESCRIPTION [0005] According to some aspects of the disclosure, a method for making an article comprises first generating a digital model of the article. The digital model is inputted into an additive manufacturing apparatus comprising an energy source. The additive manufacturing apparatus applies energy from the energy source to successively applied incremental quantities of a powder to fuse the powder to form the article corresponding to the digital model. As described herein, the powder comprises an aluminum alloy comprising 85.20-96.40 wt. % aluminum, 2.50-4.00 wt. % magnesium, 0.10-0.50 wt. % copper, 0.50-1.00 wt. % nickel, 0.50-5.50 wt. % zinc, 0-0.15 wt. % chromium, 0-3.00 wt. % titanium, 0-0.50 wt. % boron, and 0-0.15 wt. % other alloying elements, based on the total weight of the aluminum alloy. [0006] In some aspects of the disclosure, the method also comprises selectively exposing incremental quantities of aluminum alloy powder in a layer of a powder bed over a support with a laser or electron beam to fuse the selectively exposed aluminum alloy powder in a pattern over the support corresponding to a layer of the digital model of the article. Then, the method repeatedly: provides a layer of the powder over the selectively exposed layer and selectively exposes incremental quantities of aluminum alloy powder in the layer to fuse the selectively exposed aluminum alloy powder in a pattern corresponding to another layer of the digital model of the article. [0007] In some aspects of the disclosure, an aluminum alloy comprises 85.20-96.40 wt. % aluminum, 2.50-4.00 wt. % magnesium, 0.10-0.50 wt. % copper, 0.50-1.00 wt. % nickel, 0.50-5.50 wt. % zinc, 0-0.15 wt. % chromium, 0-3.00 wt. % titanium, 0-0.50 wt. % boron, and 0-0.15 wt. % other alloying elements s, based on the total weight of the aluminum alloy. BRIEF DESCRIPTION OF THE DRAWINGS [0008] The subject matter which is regarded as the disclosure is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the disclosure are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: [0009] The FIGURE is a schematic depiction of an apparatus for making an article according to the methods described herein. DETAILED DESCRIPTION [0010] Referring now to the FIGURE, an example of an additive manufacturing system or apparatus 10 includes energy source 12 that generates an energy beam 14 , a first mirror or other optical guide 16 , a second mirror or optical guide 18 , a frame 20 , a powder supply 22 , a powder processing bed 24 , sintered powder material 26 , a spreader 28 , a powder supply support 30 , and a stack support 32 . Of course, the illustration in the FIGURE is schematic in nature, and many alternative designs of additive manufacturing devices are possible. Various types of additive manufacturing materials, energy sources, and processes can be used to fabricate the air temperature sensor housing and the individual features thereof that are described herein. The type of additive manufacturing process used depends in part on the type of material out of which it is desired to manufacture the sensor housing. In some embodiments, the sensor housing is made of metal, and a metal-forming additive manufacturing process can be used. Such processes can include selective laser sintering (SLS) or direct metal laser sintering (DMLS), in which a layer of metal or metal alloy powder is applied to the workpiece being fabricated and selectively sintered according to the digital model with heat energy from a directed laser beam. Another type of metal-forming process includes selective laser melting (SLM) or electron beam melting (EBM), in which heat energy provided by a directed laser or electron beam is used to selectively melt (instead of sinter) the metal powder so that it fuses as it cools and solidifies. The FIGURE merely illustrates one potential additive manufacturing system for creating an additively manufactured article. [0011] Energy source 12 can be any source capable of creating focused energy. For example, energy source 12 can be a laser or an electron beam generator. Energy source 12 generates an energy beam 14 , which is a beam of focused or focusable energy, such as a laser beam or an electron beam. Optical guide 16 such as a mirror is present in some embodiments to deflect radiation in a desired direction. A second optical guide 18 , such as an optical head is present in some embodiments, and also directs energy in a desired direction. For example, optical guide 18 can include a mirror and be attached to an x-y positioning device. Frame 20 is used to contain powder material in powder supply 22 and in powder processing bed 24 . Powder supply 22 and powder processing bed 24 include powder material, such as or powdered metals. Powder processing bed 24 further includes fused powder 26 . Fused powder 26 is powder contained within powder processing bed 24 that has been at least partially sintered or melted. Spreader 28 is a spreading device such as an air knife using an inert gas instead of air, which can transfer powder material from powder supply 22 to powder processing bed 24 . Powder supply support 30 and stack support 32 are used to raise and/or lower material thereon during additive manufacturing. [0012] During operation, energy source 12 generates energy beam 14 , which is directed by the optical guides 16 and 18 to the powder processing bed 24 . The energy intensity and scanning rate and pattern of the energy beam 14 can be controlled to produce a desired result in the powder processing bed. In some aspects, the result can be partial melting of powder particles resulting in a fused structure after solidification such as a sintered powder metal structure having some degree of porosity derived from the gap spaces between fused powder particles. In some aspects, the result from exposure to the energy beam 14 can be complete localized melting and fluidization of the powder particles producing a metal article having a density approaching or equal to that of a cast metal article. In some aspects, the energy beam provides homogeneous melting such that an examination of the manufactured articles can detect no particle pattern from the original particles. After each layer of the additively manufactured article is completed, powder supply support 30 is moved to raise the height of powder material supply 22 with respect to frame. Similarly, stack support 32 is moved to lower the height of article with respect to frame 20 . Spreader 28 transfers a layer of powder from powder supply 22 to powder processing bed 24 . By repeating the process several times, an object may be constructed layer by layer. Components manufactured in this manner may be made as a single, solid component, and are generally stronger if they contain a smaller percentage of oxygen, hydrogen, or carbonaceous gases. Embodiments of the present invention reduce the quantity of impurities of, for example, oxygen, to less than 50 ppm, or even less than 20 ppm. [0013] The digital models used in the practice of the disclosure are well-known in the art, and do not require further detailed description here. The digital model can be generated from various types of computer aided design (CAD) software, and various formats are known, including but not limited to SLT (standard tessellation language) files, AMF (additive manufacturing format) files, PLY files, wavefront (.obj) files, and others that can be open source or proprietary file formats. [0014] As mentioned above, the powder used in the methods described herein comprises an aluminum alloy. Aluminum alloys and techniques for preparing them are well-known in the art as described, for example, in Aluminum and Aluminum Alloys, ASM Specialty Handbook, J. R. Davis, ASM International, the disclosure of which is incorporated herein by reference in its entirety. Alloys can be formed by melting the base alloy elements in a crucible curing with rapid solidification, followed by cutting and grinding operations to form a metal powder. Particle sizes for the aluminum alloy powder can range from 10 μm to 100 μm. In some aspects, the alloy elements can be combined together before forming a powder having a homogeneous composition. In some aspects, such as particles will fully melt, one or more of the individual alloy elements can have its own powder particles that are mixed with particles of other elements in the alloy mixture, with formation of the actual alloy to occur during the fusion step of the additive manufacturing process. In some aspects, the powder is “neat”, i.e., it includes only particles of the alloy or alloy elements. In other aspects, the powder can include other components such as polymer powder particles. In selective sintering, polymer particles can help to temporarily bind metal powder particles together during processing, to be later removed by pyrolysis caused by the energy source or post-fabrication thermal processing. [0015] As mentioned above, the aluminum alloy described herein comprises 85.20-96.40 wt. % aluminum, 2.50-4.00 wt. % magnesium, 0.10-0.50 wt. % copper, 0.50-1.00 wt. % nickel, 0.50-5.50 wt. % zinc, 0-0.15 wt. % chromium, 0-3.00 wt. % titanium, 0-0.50 wt. % boron, and 0-0.15 wt. % other alloying elements, based on the total weight of the aluminum alloy. The other alloying elements can be selected among those known in the art for use in aluminum alloys. In some embodiments, aluminum alloy elements form an intermetallic phase comprising magnesium, zinc, and copper. Silicon should be avoided or kept to levels under 0.25 wt. % to avoid formation of excessive amounts of Mg 2 Si intermetallic phase. In some embodiments, the alloy comprises from 1.50-3.00 wt. % titanium and 0.25-0.5 wt. % boron, based on the total weight of the aluminum alloy. In some aspects, the titanium:boron molar ratio is maintained in a range of from 3:1 to 9:1 to promote the formation of titanium diboride, which can help restrict grain growth in the microstructure. [0016] In some, more specific, embodiments, the alloy can comprise ranges of elements as specified below. In some embodiments, the alloy can comprise from 0.50-1.00 wt. % titanium and 0.10-0.25 wt. % boron, based on the total weight of the aluminum alloy. In some embodiments, the alloy can comprise from 0.10-0.50 wt. % copper. In some embodiments, the alloy can comprise 2.50-3.50 wt. % magnesium. In some embodiments, the alloy can comprise 0.50-5.50 wt. % zinc. In some embodiments, the alloy can comprise 0.50-1.50 wt. % zinc. In some embodiments, the alloy can comprise 4.50-5.50 wt. % zinc. As disclosed above, chromium can optionally be included in specified amounts. When chromium is present, the alloy can comprise chromium in an amount greater than 0 and less than or equal to 0.15 wt. %, based on the total alloy weight. In some embodiments, the alloy can comprise from 0.05-0.15 wt. % chromium. As mentioned above, other alloying elements can be present in amounts of up to 0.15 wt. %, which can be any known in the art to be present in aluminum alloys. Examples of other optional alloying or trace elements include, but not limited to, manganese, zirconium, vanadium, and nitrogen. [0017] Examples of aluminum alloys according to the description herein include those set forth in the Table below, with values provided as weight percent: [0000] TABLE Others Alloy # Cu Mg Cr Ni Zn Ti B Each Total 1 0.1-0.5 3-4 0.15 Max 0.5-1.0 0.5-1.5 2 0.1-0.5 2.5-3.5 0.15 Max 0.5-1.0 4.5-5.5 0.5-1.0 0.1-0.25 0.05 0.15 3 0.1-0.5 2.5-3.5 0.15 Max 0.5-1.0 4.5-5.5 1.5-3 0.25-0.5 0.05 0.15 4 0.1-0.5 2.5-3.5 0.15 Max 0.5-1.0 4.5-5.5 0.2 Zr 0.2 V 5 0.1-0.5 3-4 0.15 Max 0.5-1.0 0.5-1.5 0.2 Zr 0.2 V [0018] While the present disclosure has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the present disclosure is not limited to such disclosed embodiments. Rather, the present disclosure can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the present disclosure. Additionally, while various embodiments of the present disclosure have been described, it is to be understood that aspects of the present disclosure may include only some of the described embodiments. Accordingly, the present disclosure is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.	A method for making an article is disclosed. The method involves first generating a digital model of the article. The digital model is inputted into an additive manufacturing apparatus comprising an energy source. The additive manufacturing apparatus applies energy from the energy source to successively applied incremental quantities of a powder to fuse the powder to form the article corresponding to the digital model. The powder includes an aluminum alloy having 85.20-96.40 wt. % aluminum, 2.50-4.00 wt. % magnesium, 0.10-0.50 wt. % copper, 0.50-1.00 wt. % nickel, 0.50-5.50 wt. % zinc, 0-0.15 wt. % chromium, 0-3.00 wt. % titanium, 0-0.50 wt. % boron, and 0-0.15 wt. % other alloying elements, based on the total weight of the aluminum alloy.	2
FIELD [0001] The present disclosure relates to a vehicular windshield wiper de-icing apparatus and method, and more specifically, to a windshield wiper de-icing apparatus and method based in part upon a wiper blade second park position, a heating, ventilating and air-conditioning (HVAC) system, a windshield wiper de-ice switch and associated controllers. BACKGROUND [0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. Modern automotive vehicles typically have a pair of windshield wiper blades that retract to a substantially horizontal, stowed or park position when the wiper motor is turned off. During periods of freezing temperatures, the wiper blades are normally retracted to a position on or below the windshield such that the wiper blades do not benefit from heat emitting from an interior defroster outlet when heat is directed through the defroster outlet inside the vehicle cabin. The low wiper blade park position normally results in frozen wiper blades regardless of whether the blades are operating in an intermittent mode, as an example, or if they are turned off. When the wiper blades are operating in freezing temperatures, the frozen blades, normally made of rubber, accumulate ice and snow and do not properly seat against the windshield, thereby causing windshield streaks of water and ice. Additionally, contact noise results with the windshield due to the frozen, hardened wiper blades. Finally, when the wiper blades are turned on and operating, the wiper blades do not reside in a single position long enough to absorb heat emitting from the defroster vent, thereby resulting in frozen wiper blades. [0003] Accordingly, a need exists for a windshield wiping apparatus and method of operation that efficiently and effectively heats wiper blades so that the blades remain pliable, do not accumulate ice and snow and seat properly against the windshield when off or in use in freezing temperatures. SUMMARY [0004] An apparatus and method for efficiently and effectively heating windshield wiper blades so that the blades remain pliable and seat properly against the windshield when in use in freezing temperatures is disclosed. Such an apparatus and method of operation prevents windshield streaks caused by ice and snow on the wiper blades, prevents ice and snow from accumulating on the blades, and prevents contact noise of the frozen wiper blades against the windshield. Such a windshield wiping apparatus may entail a wiper motor, wiper blades attached to wiper arms and together driven by the wiper motor to position the wiper blades in a first park position, and a wiper position switch having a first switch position and a second switch position. The second switch position corresponds to a second park position of the wiper blades, different from the first park position of the wiper blades, which corresponds to a first switch position. [0005] Alternatively or additionally, a windshield wiping apparatus for a vehicle may utilize components for use in an automatic wiper de-icing mode. The components utilized may be a temperature sensor for sensing temperatures outside of the vehicle, a humidity sensor for sensing a moisture level outside of the vehicle, windshield wipers, an HVAC control module for directing air toward a designated windshield area, and a wiper control module for activating the windshield wipers when a humidity level is at or below a threshold value while the temperature sensor senses a temperature at or below a threshold value. A second wiper blade park position ensures that the wiper blades are heated and remain above freezing temperatures. [0006] A method of controlling a wiper system may entail verifying that an outside temperature is less than or equal to a threshold temperature, verifying that a moisture level is greater than or equal to a threshold moisture level, actuating an HVAC mode motor so that air is directed to a specific windshield area of the vehicle, and actuating a wiper motor such that the windshield wipers are positioned in a specific, heated windshield area of the windshield. There may be two separate and distinct park positions of the windshield wipers on the windshield. A higher second park position on the windshield ensures that enough heat will penetrate the windshield and be absorbed by the wiper blades to prevent freezing of the wiper blades. [0007] Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. DRAWINGS [0008] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. [0009] FIG. 1 is a perspective view of an automobile depicting the location of wiper blades in a low, horizontal park position; [0010] FIG. 2 is a front view of a vehicle depicting a windshield in which the wiper blades are parked at an angle P relative to the horizontal position of FIG. 1 ; [0011] FIG. 3 is an interior perspective view of a vehicular dash depicting HVAC controls, a defroster outlet, and a wiper stalk; [0012] FIG. 4 is an enlarged view of a windshield wiper stalk depicting a de-ice button; [0013] FIG. 5 is an enlarged view of the heating, ventilating and air-conditioning controls of FIG. 3 ; [0014] FIG. 6 is an exemplary view of a wiper motor depicting two motor shaft stop positions; [0015] FIG. 7 is a diagram depicting the connection scheme of the various components of a wiper control system; and [0016] FIG. 8 is a flowchart depicting operational flow of the wiper control system when in manual or automatic mode. DETAILED DESCRIPTION [0017] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. [0018] FIG. 1 is a perspective view of a vehicle 10 , such as an automobile, depicting the location of a pair of wiper blades 14 , 16 in a low park position 12 . Each individual wiper, a driver wiper 14 and a passenger wiper 16 , rests against a vehicle windshield 18 . Additionally, an outside moisture or humidity sensor 20 and an outside ambient temperature sensor 22 are depicted. While the humidity sensor 20 is depicted at a position adjacent the windshield 18 , its location is not restricted to such; likewise, while the temperature sensor 22 is depicted at the front of the vehicle 10 , it may be located elsewhere about the vehicle exterior. FIG. 1 depicts the windshield wipers 14 , 16 in a horizontal, first park position, below a heated windshield area 17 ( FIG. 2 ). The heated windshield area 17 is an interior area of the windshield where an interior windshield defroster outlet 20 ( FIG. 3 ) discharges warm air toward and against the vehicle windshield 18 . More specifically, the warm air is discharged against the interior surface of the windshield 18 at area 17 , which is above the low, horizontal park position 12 of the wiper blades 14 , 16 . [0019] FIG. 2 is a front view of a vehicle 10 . FIG. 2 depicts, the wiper blades 14 , 16 parked at an angle β relative to the horizontal wiper blades 14 , 16 depicted in FIG. 1 . When the wiper blades 14 , 16 are parked at angle β, the position or state of the blades 14 , 16 will be referred to as the heated park position 22 or angled park position. The heated park position 22 is opposed to the horizontal park position 12 , which is also referred to as the traditional or low park position. [0020] FIG. 3 is an interior perspective view of a vehicular dash depicting a heating, ventilating and air-conditioning (“HVAC”) control panel 24 . An enlarged view of the control panel is depicted in FIG. 5 . By adjusting the HVAC control panel 24 , a user may govern whether air is discharged from the windshield defroster outlet 20 , face outlet 26 , foot outlet 28 , or some combination thereof. More specifically, and with further reference to FIG. 5 , the HVAC control panel 24 has a temperature adjustment 30 , a fan speed adjustment 32 , and an outlet selector 34 . More specifically, the temperature adjustment 30 may be a knob that may be rotated to increase or decrease the temperature of the water circulated to a heating system heater core of the HVAC system. Additionally, the fan speed adjustment 32 may be a knob that may be rotated to select a speed of the blower (fan). The fan speed governs the rate at which the heated air is blown from each of the windshield defroster outlet 20 , face outlet 26 , or foot outlet 28 if such vents are selected using the outlet selector 34 . The outlet selector 34 may be a knob that may be rotated to select windshield “W.” floor “FL,” face “FA,” or face/floor “FA/FL” as air discharge options. Although specific vents and combinations of vents are depicted, still other combinations are possible. [0021] Further elaborating on the selectable outlets/vents from which heated air may be discharged, when the fan speed selector 32 is rotated to any of positions “1” through “5,” air will be blown by a fan such that the air will discharge from either the windshield defroster outlet 20 , face outlet 26 , or foot/floor outlet 28 , depending upon where the outlet selector 34 is positioned. Elaborating, the outlet selector 34 may be positioned at any of the windshield “W,” floor “FL,” face “FA,” or face/floor “FA/FL” positions. When the “W” position is selected, air will be discharged only from the windshield defroster outlet 20 . When the outlet selector 34 is positioned at the “FA” position, air is discharged only from the face vents 26 . There may be additional face vents in the dash of the vehicle, other than the three depicted in FIG. 3 . When the “FL” position is selected, air will be discharged from the floor outlet 28 . Finally when the “FA/FL” position is selected, air will be discharged from both, the face vents 26 and the floor outlet 28 . Of course air will not be forcefully discharge from any vents unless the fan speed selector knob is positioned at one of positions “1” through “5.” The fan speed selector 32 may be rotated from a fan position of “0” corresponding to an off position, to a maximum blowing volume flow rate of “5.” [0022] The temperature adjustment 30 may be rotated to adjust the temperature of air that is blown from an outlet 20 , 26 , 28 . The temperature adjustment 30 may be rotated from a cold or “C” position to an increasingly warmer position that concludes at hot or “H.” FIG. 5 also depicts a fan speed selector position of “A,” which represents an “automatic” position setting, which will be described in detail, later. [0023] FIG. 4 is an enlarged view of a windshield wiper stalk or arm that depicts a button known as a de-ice button 36 . The de-ice button 36 may be depressed to place the wiper control system into a manual wiper de-ice mode, which will be described in detail, later. [0024] FIG. 6 depicts a wiper motor 56 having a shaft 58 . Depending upon the mode of the wiper motor 56 , the shaft 58 may stop in either a first stop position 60 or a second stop position 62 . The stop positions 60 , 62 of the wiper motor govern the stop position of the wiper blades 14 , 16 on the windshield 18 . When the de-ice button 36 is not depressed, the shaft 58 of the motor 56 will stop rotation of the motor at position 60 , which corresponds to the horizontal position of the wipers 14 , 16 , as depicted in FIG. 1 . When the de-ice button 36 is depressed, the shaft 58 of the motor 54 will stop rotation of the motor at position 62 , which corresponds to the heated park position 22 . [0025] FIG. 7 depicts a wiper control system 39 that details a connection and communication scheme of the various wiper control system components. Generally, the wiper control system utilizes an HVAC control module 38 and a wiper control module 40 . The HVAC control module 38 communicates with the wiper control module 40 through a network line 42 . The HVAC control module 38 reads the ambient temperature sensor 48 such that the ambient temperature sensor inputs temperature information to the HVAC control module 38 . The HVAC control module 38 outputs control signals to the HVAC mode motor 50 , which controls the mode of an HVAC case 52 . That is, the HVAC mode motor 50 controls the position of air passage doors that govern where air is discharged inside a vehicle cabin. Although only shown in phantom, the HVAC case 52 contains the air switching doors that move in order to govern from which outlet(s) air is discharged into the vehicle cabin. Depending upon the configuration inside the HVAC case 52 , air may be directed from the defroster outlet 20 , the face outlet 26 , or the foot outlet 28 . Alternatively, air may be directed to a combination of the face outlet 26 and foot outlet 28 . [0026] Continuing with FIG. 7 , the wiper control module 40 , in addition to communicating with the network line 42 , receives input from the de-ice button 36 , also referred to as the stalk switch, and the humidity sensor 20 , also referred to as a moisture sensor. The wiper control module 40 then outputs information to the wiper blade motor 56 . While the wiper blade motor 56 is linked to the wiper blades 14 , 16 to control positioning and movement of the wiper blades 14 , 16 on the windshield 18 , details of the linkage connecting the wiper motor 56 and the wiper blades 14 , 16 are not depicted in the Figures. Operations of the automatic windshield wiper de-ice system, and manual de-ice mode, will now be described. [0027] To invoke the manual de-ice mode of the wiper blades 14 , 16 , the de-ice button 36 on the stalk 35 must be depressed. Upon depressing the de-ice button 36 , the wiper blades 14 , 16 will move from their normal, low-stowed, horizontal position, to their heated park position 22 . Manually depressing the de-ice button 36 causes the movement of the wiper blades, 14 , 16 by the wiper blade motor 56 after receiving input by the wiper control module 40 ( FIG. 7 ). The user must then manually adjust the temperature adjustment 30 , fan speed adjustment 32 , and outlet selector 34 . The temperature adjustment 30 will have to be turned toward the “H” side of the dial, as depicted in FIG. 5 , such that the blown air will permit the wiper blades 14 , 16 to maintain at least 32 degrees Fahrenheit. Additionally, the fan speed selector 32 must be turned to one of “1” through “4,” and the outlet selector 34 must be turned to “W” so that warm air is directed to windshield area 17 . When warm air is directed against the inside surface of windshield area 17 , the windshield 18 will conduct heat through the windshield, which will then transfer into the parked blades 14 , 16 . [0028] In the event that the wiper blades 14 , 16 are being utilized to wipe the windshield surface, the blades will not pass lower than an angular position, as depicted in FIG. 2 . As such, the blades 14 , 16 will momentarily stop and reverse direction at windshield area 17 . When the de-ice button is pressed, the wiper motor 56 will utilize the second stop position 62 of shaft 58 , which represents the position necessary to cause the blades to park in the heated park position 22 at angle β, relative to a lower, horizontal park position 12 that utilizes the first stop position 60 of shaft 58 . [0029] Contrary to manual activation of the wiper de-ice system, utilization of the automatic windshield wiper de-ice system does not involve invocation of the de-ice button 36 . The automatic wiper de-ice system will now be explained. FIG. 8 is a flowchart depicting an operational flow of a wiper control algorithm 70 that is utilized when the wiper control system 39 ( FIG. 7 ) is placed into automatic or “auto” mode by turning the fan speed selector 32 to “A” ( FIG. 5 ). From “start” at step 72 , the logic flow moves to step 74 at which a determination is made as to whether the de-ice button 36 on the stalk 35 is activated (depressed). If the de-ice switch 36 is activated, then the logic moves to step 80 , which activates the de-ice mode of the system. In such a situation, “activated” of step 74 means depressing a button 36 , or moving a linear switch on the stalk 35 , which may protrude from the steering column 37 . If the de-ice switch is activated, then the wiper blades 14 , 16 will move from their low park position 12 , which is essentially horizontal and below the windshield area 17 , to the designated windshield area 17 of the windshield 18 ( FIG. 2 ). When in windshield area 17 of the windshield 18 , the wiper blades 14 , 16 are in the heated park position 22 , also known as an angled park position. When in the heated park position 22 , as depicted in FIG. 2 , the wiper blades 14 , 16 will benefit from heat convection currents 21 and forced, blown heat that ultimately transfer through the windshield 18 and into the wiper blades 14 , 16 to maintain the wiper blades 14 , 16 in a non-frozen state. [0030] Regarding the transfer of heat, a blower 53 within the HVAC case 52 blows heat-laden air from the windshield defroster outlet 20 when the temperature adjustment 30 is adjusted toward the “H” side of the scale. The heat-laden forced air is directed at and contacts the interior of windshield 18 in windshield area 17 . Heat-laden air also may contact windshield area 17 by convection currents, which may run parallel to and within air currents 21 . The heat warms the interior portion of the windshield 18 at area 17 . The heat is then able to transfer through the windshield glass by conduction and subsequently warm the wiper blades 14 , 16 by conduction because the wiper blades 14 , 16 contact the windshield 18 at windshield area 17 . Because the heat contacting the wiper blades 14 , 16 causes the wiper blades to rise above freezing temperatures, that is, rise above the freezing point temperature of 32 degrees F., or 0 degrees C., the wiper blades 14 , 16 will not freeze. Furthermore, because wiper blades 14 , 16 are normally made from a material that softens with the application of heat, such as rubber, the wiper blades will wipe more effectively because they will not become frozen, and thus not become hard, and will more effectively conform to the surface of the windshield 18 . The result of non-frozen wiper blades is that streaks from ice on the wiper blades 14 , 16 will not occur. Pressing the button 36 is a manual activation of the wiper de-ice function. If the de-ice switch 36 is activated, then to deactivate the de-ice function, the de-ice switch 36 may be moved to the “OFF” position. [0031] Continuing with the flow logic of FIG. 8 , if the de-ice switch 36 on the stalk 35 is not activated, then the flow proceeds from step 74 to step 75 , where the system determines if the fan speed selector is on automatic or “A.” If the fan speed selector 32 is not turned to “A,” then because of the evaluations at step 74 and step 75 , neither the manual (de-ice button 36 ) or automatic (“A” of the fan speed selector 32 ) modes have been selected, respectively. As a result, the wiper blades 14 , 16 stay in their horizontal position 12 . The logic flow proceeds to step 86 , which ends the routine; however, the logic flow then returns to step 72 , start. [0032] If the fan speed selector 32 has been turned to “A” then the logic proceeds to step 76 where the ambient temperature, sensed by the ambient temperature sensor 22 ( FIG. 1 ) is read and compared to a value K_DE-ICE_TRHD 1 . K_DE-ICE_TRHD 1 is a threshold temperature that corresponds to a preset temperature, such as 28 degrees Fahrenheit, which is minus 2.2 (−2.2) degrees Celsius, which will be used as an example temperature. Assuming that K_DE-ICE_TRHD 1 is set at 28 degrees Fahrenheit, if the ambient temperature is greater than K_DE-ICE_TRHD 1 , then the logic flow moves to step 86 , which exits and ends the de-ice mode and returns the logic flow to step 72 , start. Alternatively, if the outside ambient temperature is less than or equal to K_DE-ICE_TRHD 1 , which for the present example is set at 28 degrees Fahrenheit, then the logic flow proceeds to step 78 where another evaluation is made. [0033] Step 78 evaluates whether an outside humidity value is greater than a preset, predetermined humidity value, referred to as K_HUMIDITY_TRHD 1 ? If the outside humidity value is not greater than K_HUMIDITY_TRHD 1 , then the logic flows to step 86 , which causes the routine to exit and end the de-ice mode, and then directs the logic to step 72 , start. K_HUMIDITY_TRHD 1 is a relative humidity threshold such as 80%, as an example. Continuing with the logic flow, if the outside humidity value is greater than K_HUMIDITY_TRHD 1 , then the logic proceeds to step 80 , and the de-ice mode is activated. Again, the de-ice mode is activated because the fan speed adjustment 32 is on “A,” and the requisite outside temperature and humidity requirements have been met. The temperature sensor 22 reads the outside temperature, while the humidity sensor 20 reads the outside humidity. While the de-ice mode is activated, as described above, the logic continues to flow to step 82 , at which an evaluation is made. [0034] Step 82 evaluates whether the outside ambient temperature is greater than K_DE-ICE_TRHD 2 . K_DE-ICE_TRHD 2 is a value that is utilized after the de-ice mode is activated. As an example, if K_DE-ICE_TRHD 1 is 28 degrees Fahrenheit, then K_DE-ICE_TRHD 2 must be greater than K_DE-ICE_TRHD 1 . K_DE-ICE_TRHD 2 may be 30 degrees Fahrenheit, or higher, for explanatory purposes of this flow logic. The outside ambient temperature must be above K_DE-ICE_TRHD 2 in order for the de-ice mode to exit and end at step 86 (turn off the de-ice function); such is the result when the step 82 evaluation is “Yes.” The logic flow ends and then immediately returns to step 72 , start. [0035] If the result of the step 82 determination is “No,” then the logic proceeds to step 84 . At step 84 , an evaluation is made as to whether the outside humidity value is less than K_HUMIDITY_TRHD 2 . If the result of this evaluation is “No” then the logic returns to step 80 to cause the wiper system to remain in de-ice mode. If the result of this determination is “Yes,” then the logic flows to step 86 , which causes the logic to exit, end and then return to begin again at step 72 . [0036] K_HUMIDITY_TRHD 2 is a value that is compared to the outside humidity value. As an example, if K_HUMIDITY_TRHD 1 is 80%, as used above, then K_HUMIDITY_TRHD 2 may be 70%. Therefore, when the outside humidity value is less than K_HUMIDITY_TRHD 2 (70% as an example), the flow logic will proceed to step 86 which exits and ends the routine, and then returns it to start 72 . However, if the outside humidity value is not less than K_HUMIDITY_TRHD 2 (70%), then the routine returns to step 80 , and the de-ice function continues with the wiper blades 14 , 16 in the heated park position 22 ( FIG. 2 ). Generally, steps 82 and 84 govern whether the ambient conditions are such to warrant continuation or exit from the automatic de-ice function. Generally, if the ambient temperature is above freezing and/or the ambient humidity is below a specific value, then the automatic de-ice function will stop. However, even if the fan speed adjustment 32 is set to “A,” automatic, if ambient conditions are not within the prescribed parameters of K_DE-ICE_TRHD 2 and K_HUMIDITY_TRHD 2 according to the flow logic, then the de-ice mode will end and exit. [0037] When in the heated park position 22 and when the fan speed selector is at the “A” position, the HVAC control module 38 automatically selects a fan speed. As an example, “2” or “3” may be selected, or the speed may vary with the outside ambient temperature. Likewise, the heated air temperature may automatically be adjusted by the HVAC control module 38 depending upon the temperature of the outside ambient air. The driver may control the speed at which the wiper arms move. In the event that the user desires a different fan speed, then the system can be turned off of the “A” setting and the stalk switch 36 can be manually switched to de-ice mode. This will permit the user to manually select any fan speed, and similarly, any forced air temperature. [0038] The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.	A vehicular windshield wiping apparatus has a temperature sensor for sensing temperatures outside of the vehicle, a humidity sensor for sensing humidity outside of the vehicle, windshield wipers moved by a motor, an HVAC control module, and a wiper control module. The wiper control module activates the windshield wipers when the moisture level is at or above a threshold value and the temperature sensor senses a temperature at or below a threshold value. The wiper motor has a first wiper park position and a second wiper park position. The first wiper park position is approximately horizontal and the second wiper park position is at an angle to the first wiper park position, in a heated windshield zone. The second wiper park position allows the wipers to remain free of ice and snow when the outside temperature and moisture levels are beyond specific thresholds or a wiper stalk switch is activated.	1
This is a continuation, of application Ser. No. 727,126 filed Sept. 27, 1976, now abandoned. BACKGROUND OF THE INVENTION This invention relates to high strength, low alloy (HSLA) steels, having low carbon content and having good mechanical properties, i.e., by tensile and toughnes measurements, and likewise in respect to ductility and formability, for instance in exhibiting the ductility required for bending. The invention is particularly concerned with steel products which can be of the nature of sheet or the like, achieved by hot deformation; the contemplated products are thus made by hot rolling to desired thicknesses and shapes, notably strip, which can be used as so produced or as subsequently further reduced by cold rolling to sheet form, i.e., strip or the like, of thinner gauge. The present improvements are notably designed to afford a steel of very low carbon content, with excellent properties in both longitudinal and transverse directions in reference to hot rolling. The steels are in the broad category defined by yield strengths of 60 ksi (60,000 pounds per square inch) and above, and for convenience of subclassification can be designated as steel products in the several respective ranges of 60-70 ksi, 70-80 ksi, and 80 ksi and higher. Indeed, a special aspect of the present invention resides in the provision of new and improved high strength low alloy steels, particularly as hot rolled strip, having yield strength of 80 ksi or better, preferably up to 85 ksi. The demand for steel products of the nature described above rests to a considerable extent on increasing need for high strength in steel strip, sheet and the like, with a minimum of weight and, understandably, at as little cost as possible. For example, steels of this nature have many uses in vehicle constructions, particularly in the automotive area where for fuel economy it is desirable to reduce the weight of the structure, yet without impairing strength. A basic purpose of HSLA steels of this class is therefore to achieve high strength properties, with a minimum of alloying elements and a minimum of processing expense. At the same time, however, it has been difficult to obtain satisfactory products in a variety of respects without employing a number of special elements for different purposes. Thus, high tensile properties and toughness can be obtained with additions of certain elements to steels of moderate to high manganese content and moderately low carbon, but avoidance of directionality in some of these properties, such as toughness and bendability, has usually required further additions, exemplified by rare earth elements, as well (in some cases) as special desulfurization. Not only have the further additions, just mentioned, contributed to the cost of the described steels, but there appears to have been room for improvement in cost reduction even as to the quantity of other elements included. With previous efforts toward economy, useful HSLA steels have been difficult to attain at the higher strength levels and with realization of practical characteristics, e.g. such as non-directionality, good toughness, and good weldability of the ultimate products. Attention is also needed to the problem of convenience in processing these steels, in hot rolling operations. In many cases of previous lower-cost HSLA compositions, very careful control has been required for finishing temperatures, coiling temperatures, and the like, within narrow ranges. Likewise, it has appeared that hot rollability is not always as good as might be desired, particularly in that some strength-promoting or other elements of the composition are believed to stiffen the hot band during hot rolling; if possible, there has been a need to reduce the hardness factor, as explained below, exhibited by the higher strength steels in such rolling operations. SUMMARY OF THE INVENTION For the above and other purposes, and notably for attainment of high strength low alloy steel products having superior properties and yet characterized by economy of cost and ease of processing, the invention, in an important aspect, consists of steel characterized by additions of the microalloying elements columbium and vanadium in low to moderate amounts, with critical, very low content of carbon the above elements and also maximum values for normal minor elements such as sulfur, nitrogen, phosphorus and aluminum being as given hereinbelow, a paramount feature of the invention is the attainment of desired strength and toughness in an unusually lean alloy, with respect both to the so-called microalloying metals and to elements such as manganese and silicon. In the new compositions, a first significant discovery is that the microalloying elements Cb and V can be employed with unusual effectiveness in a composition having a very low carbon content, e.g. not more than 0.06% (all percentages herein being by weight), and a low manganese content, being not above 0.6%, preferably not more than 0.5% and very preferably less than 0.5%. At these levels of carbon and manganese, it has been found that unusually high yield strengths are attainable with relatively moderate additions of columbium and vanadium. In particular, it is found that the effectiveness of vanadium as a strengthening agent can be greatly enhanced in the presence of a minimum amount of columbium, even at low levels of nitrogen, such as less than 0.005% (weight percent). In other words, the strengthening effect of vanadium is greater than might be expected on the basis of much of the prior art. A more specific finding is that in the new compositions, the yield strength is directly related to the sum of the percentages of these two elements Cb and V. Thus in the stated compositions, with the total of columbium and vanadium at minimum percentages of 0.07, 0.13, 0.17 and 0.22, it is possible to obtain minimum yield strengths (e.g. in both directions) of 60, 70, 80 and 90 ksi, respectively, in the hot rolled products. Moreover, there appears to be a maximum columbium level above which no further increase in strength occurs. This Cb level is related to the solubility of Cb (C, N) in austenite. Although reduction of the carbon content to levels herein contemplated, as for example to about 0.04%, does increase the solubility of Cb, the maximum useful Cb level is indicated to be about 0.15%. A second important aspect of the invention is that with the stated microalloyed compositions, especially having the prescribed or preferred levels of carbon and manganese, and with very little silicon, the rolled products are found to exhibit outstanding transverse formability and toughness without special additions or processing. Heretofore in high strength low alloy steels, such properties have been markedly less satisfactory in the transverse direction (crosswise of the direction of rolling) than in the longitudinal or lengthwise direction of the rolling path. To correct such disparity, especially in strip materials having yield strengths of 60 ksi and over, so-called sulfide shape control additives exemplified by rare earths or zirconium, which increase the cost, have been used, and alternatively or in addition, the molten steel has been subjected to desulfurization, another item of expense. In the present steels, all of such expedients can be avoided, with consequent savings of cost, and the omission of the shape control agents greatly enhances the surface quality of the strip product. It does not necessarily appear that there is a specific control of sulfide inclusions (in the sense of providing inclusions which are essentially nonplastic in rolling), as that there is an effective improvement in transverse toughness and formability without need to be concerned about inclusions. One test of bendability is by press-brake forming to a sharp internal angle such as 60°, for determining the minimum inside radius of bend attainable without cracking, for example without edge cracking of cold-sheared specimens. The radius can be determined as a function or multiple of the specimen thickness T, such as 1T, 2T, 3T, etc. The products of this invention achieved a bend at least as sharp as a radius of 1T (both directions) at the 70 ksi strength level and 2T at the 85 ksi strength level. Toughness is determinable with suitable Charpy V-notch (CVN) tests, conveniently using half-size CVN samples. With such tests, the so-called shelf energy ratio of the transverse-to-longitudinal directions for the higher strength materials of low alloy type heretofore available is normally less than 0.30 in the absence of sulfide shape control agents, but in all of the steels of this invention, such ratio is greater than 0.45. This advantage of improved transverse properties is effectively attained in steels up to 0.06% carbon -- e.g. in the range 0.04 to 0.06%, with manganese not over and indeed specifically below 0.5% (e.g. 0.3 to 0.45%); it also appears to be realized at somewhat higher levels of Mn, up to 0.6%, if carbon is kept quite low, e.g. 0.03 to 0.04%, preferably below 0.04%. As indicated above, a third attribute of the invention, notably in its preferred embodiments, is a very low total alloying content, with correspondingly lower overall cost of the final product in comparison with prior, formable steels of like high stength and so-called low alloy type. Thus, for example, advantageous ranges of total alloy elements (Mn, Si, Cb and V) in the present, relatively lean steels are 0.40 to 0.79% for 60 ksi minimum, 0.45 to 0.83% for 70 ksi minimum, and 0.51 to 0.90% for 85 ksi minimum, whereas a number of prior HSLA steels have required substantially higher totals, e.g. 1.0 to 2.0% or more for 80 to 85 ksi minimum products. A fourth aspect of these improved steels, partly indicated above in reference to transverse properties, is a significant improvement in toughness and bendability, e.g. in both directions, in comparison to various prior 60 to 80 ksi HSLA steels that have been regarded as normal, especially in the lower strength levels. This comparison is of special significance in view of the commonly much higher contents of C (e.g. approaching or at 0.10%) and Mn (as from 0.9 to 1.5%). Moreover, as above stated, the shelf energy anisotropy CVN t /CVN 1 , being the transverse-to-longitudinal ratio, is significantly greater than 0.4; for example, such ratio is 0.62 for a steel of this invention having 0.044% C and 0.30% Mn (with 0.02-0.07% Cb and 0.02-0.05% V) that attains 60 ksi yield strength and minimum bend of 1/2 T, and has a transverse CVN impact test of 28 ft.-lbs. at 70° F. on half-size specimens. In contrast with prior use of higher carbon and especially, higher manganese levels in HSLA steels, it is now found that neither C nor Mn is needed, at such levels, either for solid solution strengthening or for lowering the transformation temperature to promote fine ferrite grain size. The steels of the invention are found to have considerably better hot rollability than usual 60 to 80 ksi HSLA strip products, allowing better gauge control and attainment of thinner gauges. This property is conveniently represented by the hardness factor, being the stiffness of the hot strip during rolling relative to plain carbon steel; a lower hardness factor thus indicates improved hot rollability. Although it is known that columbium additions (while of advantage in improving grain refinement) stiffen the hot band during hot rolling, and there might be slightly better rollability with lower Cb, it has now been found that a very significant reduction in hardness factor is obtainable with the low-C, low-Mn, Cb-and-V steels of this invention, as compared with prior 60 to 85 ksi products -- indeed reaching hardness factors about as low as previous 50 ksi steels. Finally, the new products as defined are found to permit a broad range of processing conditions, i.e., as to finish temperature for the hot rolling sequence, and as to coiling temperature for the completed strip. Whereas many steels of this class have been highly sensitive to finishing and coiling temperatures when it is sought to process them to a selected, specific, high yield strength, the present steels achieve target values (or better) in yield strength over a wide range of finishing temperature, e.g. 1550° to 1750° F. and coiling temperature, e.g. 1100° to 1350° F. In consequence, practical production of these alloys on a hot strip mill is facilitated, especially through a wide range of thicknesses, as from 0.07 inch to 0.5 inch. Attainment of uniform properties throughout each coil is also greatly enhanced. Briefly summarized so to broader ranges of composition, the new products contemplate a hot rolled steel product, e.g. so reduced by at least about 50%, which contains: over 0.02% to 0.06% carbon, advantageously 0.03 to 0.06% C; 0.3 to 0.6% Mn, preferably below 0.5%, unless carbon is very low, e.g. below 0.04%; silicon less than 0.2%, very preferably 0 to 0.1% Si; 0.02 to 0.15% Cb, preferably not more than 0.12%, and very advantageously not above 0.10% Cb; 0.02 to 0.20% V, conveniently not higher than 0.17% V; and total Cb + V, 0.07% and above, depending on required yield strength, but usually not more than about 0.25% even for 85 ksi. The steels also preferably contain not more or less than certain amounts of minor elements, as for example 0.01% min. Al, 0.03 max. sulfur, and 0.03 max. phosphorus. Ordinarily, sulfur can be not less than 0.025% (a preferable maximum) without special de-sulfurization, and as indicated, such treatment is not ordinarily required for achieving nondirectionality in the present steels. In practice, it appears that sulfur content may conveniently range from 0.008 (or less) to 0.02%, aluminum from 0.02 to 0.07%, or up to 0.09%, and phosphorus from less than 0.01 to 0.015%. While nitrogen content may range as high as 0.025%, an advantage of the invention is that ordinarily, special provision for nitrogen need not be made, and full advantages can be expected with nitrogen in the range of 0.007% and below, e.g. to 0.003%. The steel is very preferably aluminum-killed -- such operation being performed in conventional manner and for conventional purposes. DETAILED DESCRIPTION The steels of the invention having compositions within the ranges stated above, or indeed within more specific ranges related to particular and notably advantageous aspects of the invention, are prepared in an essentially conventional way, e.g. for making a very low carbon, low alloy steel, following known practices for producing a clean ingot product, with good control of desired contents of small percentages of alloying elements. Thus the basic melt is achieved in a customary manner, as in a standard electric or basic oxygen furnace, appropriate attention being paid to the desired low carbon content. It is understood that carbon levels as low as 0.03% or slightly lower are effectively obtainable without special treatment of the melt after tapping, and indeed the carbon ranges contemplated as preferred for the present steels appear to pose no special problem in melting practice. Additions of the several required elements to the basic charge of scrap, iron and the like are made in the manner appropriate for such materials. To the extent that the desired low level of manganese is not inherently present in the charge, this element may be added in the furnace and/or ladle, e.g. as ferromanganese. Very preferably the minor, i.e., microalloy additions, Cb and V, are effected by adding appropriate material, for example as ferroalloys, to the melt in the ladle after tapping. There is ordinarily no need to add silicon or, as explained above, to introduce additional nitrogen into the melt. It is greatly preferred that the steel compositions of the invention be fully de-oxidized; although other de-oxidation practice may be used, satisfactory results are achieved by the usual killing with aluminum. Thus aluminum can be added to the ladle for de-oxidizing so that oxygen is reduced to values, for example, less than 0.005%. After pouring the steel of the melt, which has been suitably controlled as to content of the several required elements, the resulting ingots are handled in conventional way, being reduced to slab or the like for final reduction by hot deformation. For most purposes, this is effected by hot rolling, for example through the requisite number of passes, to a selected finish temperature. A special advantage of the invention is that this finish temperature may be chosen over a wide range, for example from 1550° to 1750° F. (or conceivably as high as 1800° F.) without particular regard to the precise composition as to microalloy elements or as to the precise minimum yield strength desired. It appears that increase of yield strength with increase of finish temperature is not of great or practical significance over the stated range. The product delivered by the hot mill at the selected or determined temperature within the above range, being strip or other shape as sheet or the like, is appropriately cooled to a selected temperature. Such cooling may be at a rate of 15° to 135° F. per second (with air, or with water spray or jet if needed), in accordance with known procedure for these types of steel. The selected temperature to be reached thus for coiling or other collecting of the hot-rolled material (including piling of sheets) may be in the range of 1100° to 1350°, or even up to 1400° F. After such collection, e.g. after the coiling of strip, the product can be allowed, in usual fashion, to cool very slowly. As in the case of the finish temperature, this coiling temperature may vary within the range (especially above 1100° F. and below 1350° F.) without substantial effect upon, or other than very minor relation to, the desired yield strength of the product; strength properties are thus determinable essentially wholly by the elemental composition. In fact, a valuable aspect of the invention is that at prescribed levels of carbon and manganese, and with both elements Cb and V present, in amounts of at least 0.02% of each, the strength properties of the product are primarily determined by the total quantity of these microalloying elements. The improved high strength, low alloy steels can be produced, as hot rolled product, in a usefully wide variety of gauges, for instance from about 0.05 to 0.5 inch. Although the middle part of the range, say from about 0.1 to about 0.25 inch, may have considerable utility, a feature of the invention is the availability of the product to be hot rolled to a very reduced thickness in the above broad range, particularly including the very thin gauges. It is conceived that some adjustment of composition, in the sense of less percentages of columbium and correspondingly greater percentages of vanadium, nevertheless within the individual and total ranges for these elements, may be useful for best rolling results at lower, and perhaps also at upper, values of thickness in the above-described total range. Thus, at the very thin gauges, the increase of vanadium relative to columbium provides better rollability, with less stiffening and particularly with lower rolling load requirement. Indeed the availability of such compositions is a feature of the present invention, affording extension of feasible thickness range for the products. At the very heavy gauges, it may also sometimes be desirable to decrease the proportion of columbium and increase that of vanadium so as to avoid excessive stiffness of the produced hot band and thus facilitate coiling and uniformity of gauge. The products have been extensively tested throughout a significant range of compositions, with experimental results fully supporting the properties and characteristics described herein. A considerable number of tests involved heats in an induction heated furnace suitable for pouring 100-pound ingots, under laboratory operation. The base chemistry of the material produced was about that of SAE 1006-grade steel with very low phosphorus and sulfur levels, the specific content of elements being as indicated below. These laboratory heats were air-induction melted and were fully de-oxidized with aluminum prior to pouring into the 100-pound ingots. The ingots were hot reduced and ultimately processed by hot mill rolling, in the manner of hot strip production, i.e., yielding, after a series of passes, a product of thickness of the order of 0.1 inch. Finish temperatures for the hot rolling were varied between 1550° and 1750° F. Although somewhat higher strength properties were achieved at the higher finish temperatures, the difference was generally small, to the extent that in most cases, values throughout the range can be used as may be convenient, without failing to achieve a selected minimum target strength in a practical sense. In these tests, the strip samples were cooled at a rate of about 40° to 50° F. per second to a selected coiling temperature, and were thereafter collected at such temperature, by coiling or in a manner to simulate coiling. These collecting temperatures were varied over a range of 1000° to 1340° F., it being found that variation in properties was relatively small over a wide range, e.g. approximately 1100° to 1350° F. Specimens from the several experimental products, i.e., after the completed strip had cooled to room temperature, were subjected to tests of mechanical properties, as will be understood from reports of such tests herein. Unless otherwise indicated, it will be noted that in all cases, yield strength was tested as the conventional 0.2% offset determination, in the longitudinal direction of the sample. Inasmuch as yield strength is almost invariably lower in the longitudinal than in the transverse direction, the determinations of yield strength can be considered to represent values at least as high as are found in both directions of the rolled product. Tests of impact strength and of bendability were made in conventional ways as elsewhere herein explained. A number of steel compositions were produced in the foregoing manner, of which significant examples are set forth in the following table I: TABLE I______________________________________(values in weight percent)SteelNo. C Mn Si Cb V Al Cb+ V______________________________________1 0.04 0.38 0.06 0.035 0.06 0.01 0.0952 0.04 0.39 0.05 0.03 0.09 0.01 0.123 0.045 0.40 0.06 0.04 0.11 0.02 0.154 0.046 0.40 0.06 0.038 0.15 0.01 0.1885 0.049 0.41 0.06 0.071 0.15 0.02 0.2216 0.046 0.40 0.05 0.10 0.15 0.01 0.257 0.04 0.37 0.05 0.09 0.06 0.01 0.15______________________________________ These have been identified, solely for reference herein, by the consecutive numbers in the left-hand column. In all cases, the content of phosphorus was less than 0.008%, the sulfur content was about 0.008%, and nitrogen was about 0.005%; as will be understood, the balance of the compositions consisted of iron and incidental impurities. These steels were all, of course, aluminum killed. Other tests demonstrated that the sulfur content was not critical in most cases and could go up to 0.02% or in some cases even 0.025% without introducing undesired directionality in the properties of toughness and formability. Although phosphorus and nitrogen contents up to 0.03% of each could be tolerated, good practice and emminently satisfactory results were had with low values of each of these elements, i.e. a maximum P of about 0.015% and of N about 0.01%. The total of columbium and vanadium for each of the above heats is also listed, and it was found that the strength category, i.e., in yield strength, of the several heats could be directly correlated with the microalloy total. Thus heat No. 1 afforded yield strength above 60 ksi, while heats Nos. 2, 3 and 7, being upwards of 0.12% total microalloy elements, exhibited yield strengths of 70 ksi and above, i.e., in the range below 80. Finally, heat No. 4 afforded 80 ksi yield strength or better, while heats Nos. 5 and 6 exhibited strengths in a higher part of the range above 80 ksi, specifically values of 85 or more. All of these steels showed good properties of toughness and formability, with a high ratio of transverse-to-longitudinal toughness measurement. The measured properties were essentially as indicated elsewhere herein for these products, the actual toughness values being at least comparable to those of prior HSLA steels and the above-mentioned ratio being substantially over 0.4, and indeed commonly at least 0.6. Transverse bendability was very good, ranging from 1/2 T for 60 ksi product, through 1T for 70 ksi material, going no higher than 2T for 85 ksi steel. Other examples of steels embodying the present invention are set forth in the following table, it being understood that the content of silicon was very low, e.g. not more than 0.05%. In each case, maximum values were 0.009% P, 0.020% S, and 0.06% Al. TABLE II______________________________________SteelNo. C Mn Cb V N(approx.) Cb + V______________________________________8 0.05 0.40 0.10 0.12 0.006 0.229 0.05 0.40 0.02 0.10 0.006 0.12______________________________________ In these steels of Table II, No. 8 represents a product exhibiting yield strength over 80 ksi, with good toughness and bendability in both directions, while steel No. 9 is a product of 70 ksi category, especially designed for rolling to very light gauge, e.g. below 0.09 inch. As will be noted, the relative proportion of vanadium to columbium is greatly increased, with corresponding, greater ease of rolling, to justify the slightly greater cost. As has been explained, the total of the microalloying elements columbium and vanadium governs the strength properties of the product, and there appears to be some synergism between these elements in these particular steels, in that increments of vanadium exhibit greater increments of yield strength when columbium is present, than in corresponding steel compositions lacking columbium. Hence there is unusual advantage to the combination of these elements in the present alloys, with carbon and manganese in extremely low amounts. As indicated, manganese is commonly kept below 0.5% in order to achieve the improvement in transverse properties, especially if carbon is 0.04% or higher, i.e., to 0.06%. Indeed, it is preferred that manganese be kept no higher than 0.45% under these circumstances. On the other hand, if carbon is reduced below 0.04%, it appears that amounts of manganese can be used, e.g. above 0.5% and even to 0.6%, preferably with some assurance that sulfur is relatively low, e.g. below 0.02%. Thus good transverse properties are indicated to be attainable with carbon at 0.03% and manganese at 0.6%. The minimum totals of columbium and vanadium for obtaining at least 60 ksi yield strength are about 0.07%, for 70 ksi at least about 0.12% (preferably 0.13%), and for 80 ksi, the total should be at least 0.17% and preferably a little higher, e.g. 0.18%. The alloys attain unusual advantages, particularly in mechanical properties and lack of directionality, with notably low expense and ease of processing. The products, moreover, have good surface properties and are capable of satisfactory welding, e.g. by spot welding and in other ways. Yield strengths above 80 ksi are readily attainable; indeed, the compositions disclosed herein for such purpose can be considered as a special area of the invention. For such products, it is preferable, especially to reach 85 ksi or better, that the carbon content be at least about 0.045%, or even 0.05%, in order to assure availability of conversion to carbides of columbium and vanadium, as may be desired for realizing the strength characteristics of these elements. As indicated, the silicon content of all the above examples of the invention is very advantageously quite low, but it is conceived that some high strength products in the 60-ksi and 70-ksi categories may constitute new and useful compositions even with silicon up to 0.4%. Although the steels are conveniently defined by their properties as produced by the hot rolling, coiling and cooling procedure, it will be understood that an ultimate product embodying a steel of the invention may have had further processing that affects the value of a property, for example decrease in yield strength upon cold rolling and annealing. It is to be understood that the invention is not limited to the specific features herein set forth for example but may be carried out in other ways without departing from its spirit.	High strength low alloy steels, produced as strip or the like by hot rolling, permit unusual economy of alloying ingredients while achieving superior mechanical properties. With a composition containing specifically low carbon and low manganese, and moderate proportions of both columbium and vanadium, preferably with no requirement of silicon. Yield strengths in a range to and above 80 ksi are attainable depending on the total of columbium and vanadium, and excellent properties of toughness and formability are exhibited in transverse as well as longitudinal directions without adding special sulfide shape control agents. Processing conditions, for hot rolling and coiling, can be selected over wide temperature ranges, for convenience of control, e.g. to achieve product uniformity. Rolling load requirements are acceptable and can be reduced to facilitate production of thin strip by reducing the ratio of columbium to vanadium, without impairing the way in which columbium appears to effectuate superior realization of the strengthening effect of vanadium in those compositions.	2
This application is a continuation of application Ser. No. 08/258,469, filed Jun. 10, 1994, now abandoned. BACKGROUND OF THE INVENTION The present invention relates to the area of devices which protect neon border lights. Neon border lights are frequently damaged or destroyed due to their location in relatively high traffic display windows. As display windows, retail and otherwise, are removed and updated or as maintenance persons access the area around the neon border lights, the resultant damage and destruction to the neon border lights requires repair and/or replacement of the neon border lights with significant, but unnecessary, attendant costs to the owner of the display borders. Previous solutions which addressed the problems concerning the rigidity of neon or fluorescent light structures and the dangers and costs generated by their destruction have included complex encasement devices such as plastic coatings or sleeves, or structurally inappropriate mounting accessories which were not originally developed to protect an entire length of a neon border light. In U.S. Pat. No. 3,576,304 granted to Gillemot on Apr. 27, 1971, a mounting accessory is disclosed for securing and detachably mounting flexible cable, i.e. interior telephone cables. The accessory comprises C-clips made from resilient elastomeric material, sized to receive and grip cables provides deep V-notches within the lateral walls of the C-clip to facilitate insertion and flexing of the C-clip. The C-clips have a planar surface posteriorly located from the C-clip opening and utilize interlocking barb and fiber separable strips. The '304 patent does not disclose a mounting accessory intended to run the length of the mounted item, addresses concerns more appropriate to flexible telephone cables than to rigid neon tubing and has the distinctive structural profile of a C-clip with V-notches. In U.S. Pat. No. 4,924,368 granted to Northrup on May 28, 1990, a protective containment sleeve for a fluorescent lamp is disclosed in which the sleeve is attached to the circumference of the end of a fluorescent tube by adhesive and completely encases the lamp providing a sleeve to withstand mechanical stresses to the fluorescent lamp and to protectively contain a damaged fluorescent lamp should it explode. The approach of the '368 patent is to protect against minimal mechanical stresses to the lamp and to contain an exploded lamp after it has been destroyed. The present invention has a preventative focus in that it allows for easy removal of the protected light thus avoiding much of the dangers associated with display changes or display maintenance while still allowing for the protective and containment features of other devices. SUMMARY OF THE INVENTION The present invention is directed to devices which are capable of mounting and protecting elongate lighting devices and more particularly, neon lighting for store window borders. The focus of the present invention is to provide an easy and cost effective method for detachably mounting a neon light border while incorporating the aspects of protecting the light from mechanical stresses and providing for the safe containment of a damaged light. The invention is comprised of a transparent elongate protective tube having two parallel interior channels with cross sectional areas which are adapted to fit the light emitting and terminal bent end portions of a neon border light. In one embodiment of the present invention, the center of the light emitting tube is placed in a channel close to the window, while the bent blackened (non-light emitting portion) ends are placed in a channel away from the window. As a variation, both the center of the light emitting tube and the bent blackened (non-light emitting portion) ends may run next to the window in two parallel channels. In a preferred embodiment, the protective tubing is constructed from flexible, yet semi-rigid polymers. The protective elastomeric tubing has an elongated planar mounting surface which may be used for attaching hook and loop type fastener strips, commonly referred to as Velcro brand fasteners, or for utilizing any other type of mounting apparatus, such as a screw and eyelet system. The planar mounting surface also allows for a maximum transmittal of light due to the proximity to the channel which seats the light emitting portion of the neon border light to the window upon which the light will be mounted. Upon inserting a neon border light into the protective tubing, the entire assembly can then be secured to the interior of a window surface. Thus, the entire neon border light is thereby protected as it can be easily removed or quickly reattached to any store window. It also entirely surrounds and protects a neon border light from bumps and abuse occurring during cleaning or display work which can otherwise cause severe damage or destruction to a neon border light. Further, in the event of breakage of the neon border light this invention provides for a safe containment of the broken light thus reducing the dangers involved during or after that sort of mishap. OBJECTS OF THE INVENTION It is therefore an object of the invention to provide a cost efficient and easy to use protective mounting device for neon light borders. A further object of the invention is to provide the easy removal and reinstallation of the protectively mounted neon light border for access to the display area by personnel changing the display or providing maintenance to the display area. Another object of the invention is to reduce the damage or destruction of lighting structures in display areas. Yet another object of the invention is provide a protective mounting device running the entire length of a neon border light structure. A still further object of the invention is to provide for the safe containment of a damaged light structure. A further object of the present invention is to provide a protective mounting device which can use a variety of fasteners to attach the mounting device to a window or window frame, such as Velcro, plastic tang rivets, screws, etc., that are all simple and inexpensive to use. Still another object of the invention is to prevent transmittal of externally applied mechanical stresses to the light structure resulting in damage or destruction. BRIEF DESCRIPTION OF THE DRAWINGS Other objects and advantages of the present invention will become more apparent upon reference to the following specification and annexed drawings in which: FIG. 1 is a cross sectional cut away perspective view of line 1--1 of FIG. 4 of a preferred embodiment of the invention; FIG. 2 is an end perspective cut away view of a second preferred embodiment of the protective mounting device showing a neon light border tube being inserted lengthwise; FIG. 3 is a cross sectional cut away perspective view of a third preferred embodiment of the invention; and FIG. 4 is a top view of a protective mounting device shown containing an elongate neon light emitting device. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings in detail, FIG. 1 shows a neon lighting protective mounting device 10 comprising a transparent elongate tube 20 containing an interior chamber 38. The interior chamber 38 includes a first parallel interior channel 22 and a second parallel interior channel 24. The interior chamber 38 houses an elongate light emitting device 12. The elongate light emitting device 12 includes a central light emitting portion 14, a first terminal portion 16, and a second terminal portion 18 (shown in FIG. 4). The central light emitting portion 14 rests in the first parallel interior channel 22, and the first terminal portion 16 and second terminal portion 18 (shown in FIG. 4) rest in the second parallel interior channel 24. The transparent elongate tube 20 incorporates an elongate planar mounting surface 26. In this preferred embodiment of the invention, a hook or loop type fastener strip 28, commonly known as VELCRO®, is attached to the elongate planar mounting surface 26. In this preferred embodiment of the invention, the transparent elongate tube 20 is constructed as a unitary, extruded material. Suitable materials must be flexible, semi-rigid, resilient, relatively impervious to the degrading effects of heat and ultraviolet radiation and have appropriate light transmitting qualities for effective transparency. Suitable materials include, but are not limited to, polyvinyl resins and nylon. The external structure of the transparent elongate tube 20 in this preferred embodiment is "D" shaped in cross-section as shown in FIG. 1 and is "keyhole" shaped in cross-section as shown in FIG. 2; however, the invention is known to include a range of cross-sectional configurations in other preferred embodiments. The invention may also consist of tubing of various appropriate lengths. In one preferred embodiment of the invention, the interior chamber 38 is shaped like an ellipse as shown in cross-section in FIG. 1. The combination of the first parallel interior channel 22 and the second parallel interior channel 24 comprises a spatial majority of the interior chamber 38 in the elliptical embodiment of the invention as shown in FIG. 1. In another embodiment of the invention, the interior chamber 40 is shaped like a pinched ellipse as shown in cross section in FIG. 2. Here again the first parallel interior channel 22 and the second parallel interior channel 24 comprise a spatial majority of the interior chamber 40. Referring back to FIG. 1, the first parallel interior channel 22 accepts the central light emitting portion 14 of the elongate light emitting device 12 and seats the same upon insertion of the elongate light emitting device 12 into the interior chamber 38. The central light emitting portion 14 of the elongate light emitting device 12 is the portion responsible for emitting light. In a preferred embodiment, the first parallel interior channel 22 is distal to the elongated planar mounting surface 26 such that upon insertion and seating of the central light emitting portion 14 of the elongate light emitting device 12, there is relatively little distance from the elongate light emitting device 12 to a store window, allowing for maximum illumination by the light emitting device 12. FIG. 2 shows the neon lighting protective mounting device 110 which shows the elongate light emitting device 12 being slidably inserted therein. FIG. 2 also demonstrates how the second parallel interior channel 24 accepts the first terminal portion 16 of the elongate light emitting device 12 and seats the same upon the insertion described above. The first terminal portion 16 of the elongate light emitting device 12 is a non-illuminating portion of the elongate light emitting device 12 and is generally painted or coated black. Upon complete insertion of the elongate light emitting device 12 into the transparent elongate tube 80, the first terminal portion 16 of the elongate light emitting device 12 becomes protectively encased within the second parallel interior channel 24. Structurally, the first parallel interior channel 22 is located proximal to a store window to provide maximum light transmission. FIG. 3 shows neon lighting protective mounting device 120. The parallel interior channels 22 and 24 of the previous preferred embodiment become separate channels 44 and 46 and are intersected by a fissure 42. The fissure 42 extends perpendicularly across the transparent elongate tube 100. The fissure 42 extends from a distal exterior surface 50 through the first and second parallel interior channels, 44 and 46, and up to but not including the elongated planar mounting surface 26. This embodiment of the invention has the advantages of more securely seating and separating the central light emitting portion 14 of the elongate light emitting device 12 from the first terminal portion 16 and second terminal portion 18 of the elongate light emitting device 12. This embodiment further allows the invention to be used with elongate light emitting devices 12 where lengthwise insertion of a elongate light emitting device 12 into the protective mounting device 10 is not feasible. The fissure 42 is separable, providing for a jaw-like opening of the transparent elongate tube 100 to expose both parallel interior channels 44 and 46. In this position, the central light emitting portion 14 and the terminal portions 16 and 18 of the elongate light emitting device 12 can be seated directly into the first and second interior channels, 44 and 46. Closure of the transparent elongate tube 100 is achieved by allowing the transparent elongate tube 100 to elastically resume its original shape. The transparent elongate tube 100 may further be secured into the closed position by a first closure element 52 removably engaging a second closure element 56. The first closure element 52 is located on the first marginal portion 54 of the distal exterior surface 50, and the second closure element 56 is located on the second marginal portion 58 of the distal exterior surface 50. In another preferred embodiment of the invention, once the elongate light emitting device 12 is inserted or seated into the protective mounting device 10, the now protected elongate light emitting device 12 may be mounted in any place desirable to have an elongate light emitting device 12 by attaching any means of fastening the protected elongate light emitting device 12 to an elongate planar mounting surface 26. Although a variety of mounting methods are contemplated for this purpose, including adhesives, clips or hooks, and screws, a preferred embodiment utilizes hook or loop type fastener strips 28 as shown in FIGS. 1, 3, and 4. Hook strops 28 are shown in FIGS. 1 and 3, while the corresponding loop strips 29 are shown in FIG. 4, A hook or loop type fastener strip is preferred because hook or loop type fastener strips allow for the easy detachable mounting and securing of the protected elongate light emitting device 12 whereas other mounting devices and schemes are not easily detachable. Further, other mounting devices tend to be permanent and may damage the elongate planar mounting surface 26. In the preferred embodiment shown in FIGS. 1 and 3, a first hook strip 28 is attached to the elongate planar mounting surface 26 of the transparent elongate tube 20 and a corresponding loop strip is anchored to an external mounting surface such as the interior glass or frame of a store window. FIG. 2 also shows a preferred embodiment of the invention where the elongate planar mounting surface 26 can be extended beyond the edge of the transparent elongate tube 80, becoming mounting flange 82. The mounting flange 82 is provided with a plurality of apertures 84. Screws 86 may be driven through apertures 84 into a nearby window frame, wall, etc. to secure the neon lighting protective mounting device 110. In this fashion, the neon lighting protective mounting device 110 may be attached to a fixed surface permanently through the use of screws, nails, bolts, etc. The neon lighting protective mounting device 110 could be fixed to a horizontal window frame or wall ledge so that the first and second parallel channels 22 and 24, as shown in the embodiment of FIG. 2, or 44 and 46, as shown in the embodiment of FIG. 3, are aligned parallel to the window pane, wall, etc. Likewise, the neon lighting protective mounting device 110 could be fixed to a vertical surface so the parallel channels 22 and 24, or 44 and 46 are aligned perpendicular to a window surface or wall, ceiling, etc. FIG. 4 shows one preferred embodiment of the neon lighting protective mounting device 140 in top view, although other preferred embodiments could similarly be used. The elongate light emitting device 12 is secured within the within the transparent elongate tube 130. The loop type fasteners 29 can be seen attached to the elongate planar mounting surface 26. An electrical connecting line 60 extends from the elongate light emitting device 12 and runs along a length of the second parallel interior channel 24 or 46, typically exiting to engage with a transformer connected to an electrical power source (not shown). While the invention has been described in connection with preferred embodiments, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the spirit or scope of the invention and all reasonable equivalents are intended to be covered by the appended claims.	A novel neon lighting protective mounting device comprised of a transparent elongated elastomeric tubing or sleeve having two parallel interior channels which are able to seat both the central light emitting portion of a neon border light as well as the terminal blackened bent portions of a neon border light. The protective tube further has a flat surface extending its length which allows maximum illumination of the central light emitting portion of the neon border light through the transparent tube and which also allows the protective tubing to be removably mounted to the interior surface of a store window by using Velcro strips, screw and eyelet mounts or other type of attachment device.	5
FIELD OF THE INVENTION [0001] This invention relates to motor vehicles, especially large trucks, and in particular it relates to a modular rear axle assembly of such a vehicle. BACKGROUND OF THE INVENTION [0002] A typical construction for a large truck is based on a steel chassis frame. A cab for the driver is mounted atop the frame. An engine is mounted on the frame in front of the cab. Various components of a drivetrain that couples the engine to driven wheels of a rear axle assembly are supported on the frame, as are components of various other systems such as brake and steering systems. In the case of a highway tractor, a fifth wheel is mounted atop the rear of the frame. [0003] One or more rear drive axles are suspended from the chassis frame by a suspension system that comprises various components that provide resiliency in conjunction with damping. The spring/damping characteristic of a suspension system is typically selected to provide desired ride and handling for a particular vehicle use vocation, and is based on the mass of the truck and the maximum load that the truck carries. Truck suspension systems often include components whose characteristics are adjustable in order to better adapt the truck to different load masses. [0004] Assembly of axles, especially tandem axles, to chassis frames requires manufacturing processes that can assure proper alignment. In an assembly line process, some trucks will have more precise alignment than others due to tolerance variations. Imprecise alignment of the rear axle of a tandem axle can create an off-center thrust angle, a condition sometimes referred to as “dog tracking”, that a driver corrects by turning the steering wheel off-center. This contributes to steering wheel misalignment and leads to accelerated tire wear. The presence of a scrub angle between front and rear axles of a tandem axle is another undesired condition. [0005] Trucks are typically manufactured by fastening individual components to a chassis frame using various brackets, cross members, and fasteners. Large numbers of holes have to be drilled in side rails of the chassis frame. Such a manufacturing process is typically part- and labor-intensive. It also requires a number of different assembly stations for which ample floor space in an assembly plant is required. [0006] Certain trailers of the type that are hauled by highway tractors have rear axle modules, sometimes referred to as bogies, or sliders, that contain multiple axles and various suspension components that mount the axle(s) on a structure that is itself fastened to the underside of the trailer body. The use of a modular axle assembly in trailer manufacture can provide certain manufacturing efficiencies because of fewer operations and the ability to better align each axle to the other in the module, and they are assembled in significantly smaller main line workstations that are 12′×12′, more or less, rather than 12′×50′, more or less, often found in conventional highway tractor main line workstations. This results in considerable manufacturing labor and floor space savings. SUMMARY OF THE INVENTION [0007] The inventors believe that a truck manufacturing process can be improved by designing a truck to have a rear axle module that is assembled as a unit to a chassis frame. Such a module can be designed to provide desired characteristics, such as strength, alignment consistent with those of the chassis frame, while using fewer parts and fewer main line assembly stations in the overall highway tractor manufacturing process. [0008] A smaller amount of floor space and fewer assembly operations are needed in a truck manufacturing plant for assembling a rear axle assembly to a chassis frame when the assembly embodies principles of the present invention. Because of the ability to align the axles in the module away from the truck into which the module is to be assembled, not only can the axle-to-axle alignment be more precise than if individual axles and their suspensions are installed on a chassis frame, but less complicated alignment procedures are required in the truck assembly plant because the axles are already pre-aligned in the module. These factors can significantly improve manufacturing efficiency and product quality while reducing in-plant manufacturing costs. [0009] The replacement of multiple-part and shim-adjusted rear suspension systems currently seen in trucks by the new modular rear axle assembly embodying fixed length tie rods on one side and threaded lockable turnbuckles on the other side can provide a precisely aligned, sturdier chassis construction that possesses better steering wheel and tire alignment and delivers better road handling performance. Because a truck that embodies principles of the invention is expected to incur fewer alignment and suspension issues, manufacturer warranty costs should be less and customer satisfaction should be enhanced. [0010] Furthermore, the inventive module can be implemented in existing commercial truck and bus product offerings without major chassis modifications. It can also be produced in various models that differ in types of suspension and/or in the axles themselves to accommodate various highway tractor vocations. Such models can be designed to fit various truck chassis frames if those frames have the same size right and left frame rails and the same width. [0011] While the ability to efficiently assemble such a module to a chassis frame also provides for efficient disassembly for service when needed, it also provides module interchangeability. As such it affords truck manufacturers and truck dealers a new business opportunity by enabling an existing truck that would be meet a prospective customer's need except for its particular drive axle(s) to be quickly adapted to meet the customer's requirement by replacing the rear axle module on the truck with one that the customer needs. By stocking different rear drive module models in inventory, a manufacturer or dealer can quickly adapt an already manufactured truck and make an immediate sale or lease that otherwise might not be made. [0012] Accordingly, one generic aspect of the invention relates to a chassis frame and rear axle module combination. [0013] The chassis frame comprises right and left side rails often referred to as frame rails that run lengthwise of the chassis frame and that comprise respective channels each of which has an interior bounded by a vertical wall and horizontal top and bottom flanges that extend from top and bottom of the vertical wall toward corresponding flanges of the opposite side rail. [0014] The rear axle module comprises right and left channels each of which has an interior bounded by a horizontal wall that is disposed against the bottom flange of a respective one of the right and left side rails and inner and outer vertical flanges that extend from the respective horizontal wall and are disposed respectively against free ends of the flanges of the respective side rail and the vertical wall of the respective side rail. [0015] Right and left fillers respectively fill the interior of the respective side frame rail between the inner vertical flange of the respective module channel and the vertical wall of the respective side rail. [0016] At least four fasteners fasten each rear module channel to the respective side rail channel to place the respective side rail channel and filler in horizontal compression. [0017] A further generic aspect of the invention relates to a method of assembling an axle module to a chassis frame that has right and left side rail channels running lengthwise of the chassis frame, each channel having an interior bounded by a vertical wall and horizontal top and bottom flanges that extend from top and bottom of the vertical wall toward corresponding flanges of the opposite side rail. [0018] The method comprises filling the interiors of the side rails with fillers and positioning right and left channels of the axle module below the right and left side rails respectively and relatively moving the module and frame toward each other to cause an interior of each channel of the module that is bounded by a bottom wall and inner and outer upright flanges to fit to the corresponding side rail with the bottom wall of each module channel being disposed against the bottom flange of the corresponding side rail and with the inner flange of each module channel disposed against free ends of the flanges of the respective side rail and the corresponding filler and with the outer flange of each module channel disposed against the vertical wall of the respective side rail. [0019] The method further comprises fastening each module channel to the respective side frame rail channel to place the respective side rail channel and filler in horizontal compression. [0020] Another aspect of the invention relates to a method of re-equipping a truck that has one particular model of rear drive axle and suspension module with a different model. The highway tractor is designed in such a way that it facilitates quick disconnection from the rear axle module. This includes and is not limited to electrical, pneumatic and hydraulic logic and control circuits. [0021] The foregoing, along with further features and advantages of the invention, will be seen in the following disclosure of a presently preferred embodiment of the invention depicting the best mode contemplated at this time for carrying out the invention. This specification includes drawings, now briefly described as follows. BRIEF DESCRIPTION OF THE DRAWINGS [0022] FIG. 1 is a top plan diagrammatic view of a chassis frame showing a non-zero thrust angle. [0023] FIG. 2 is a top plan diagrammatic view of a chassis frame showing a scrub angle for a tandem axle. [0024] FIG. 3 is a top plan view a chassis frame with a modular rear axle assembly in accordance with principles of the present invention. [0025] FIG. 4 is an end view in the direction of arrows 4 - 4 in FIG. 3 . DESCRIPTION OF THE PREFERRED EMBODIMENT [0026] FIG. 1 shows a truck chassis 10 having steered wheels 12 at the front and tandem drive axles 14 , 16 at the rear. The drawing shows the rear tandem axle 16 in a condition of misalignment relative to axle 14 creating a non-zero, or off-center, thrust angle, that causes the condition referred to as “dog tracking”. As discussed earlier, this condition contributes to steering wheel misalignment because the driver must over- or under-steer to correct for it, and the condition leads to accelerated tire wear. [0027] FIG. 2 shows the presence of a scrub angle (marked as such) between the front and rear tandem drive axles due to axle 14 being misaligned toward the left of the chassis frame centerline and axle 16 being misaligned toward the right. This condition also creates drivability and wear issues. [0028] The inventive drive axle module 18 and its association with chassis frame 10 are presented in FIG. 3 (top view) and FIG. 4 (end view). [0029] Frame 10 comprises right and left side rails 22 , 24 running lengthwise of the frame and comprising respective steel channels. As particularly seen in FIG. 4 , each channel has an interior bounded by a respective vertical wall 26 R, 26 L, a respective horizontal top flange 28 R, 28 L, and a respective horizontal bottom flange 30 R, 30 L. The channel interiors confront each other across the width of the frame, with the flanges of each extending from the top and bottom of the respective vertical wall 26 R, 26 L toward corresponding flanges of the opposite channel. Frame 10 comprises one or more cross members (not shown) at other locations along the frame length. [0030] Module 18 comprises a sub-frame structure for association with side rails 22 , 24 , and suspension components that couple tandem drive axles (not shown) to that structure. When the sub-frame structure is associated with and fastened to frame 10 , the tandem drive axles are inherently placed in proper alignment with the chassis. [0031] The sub-frame structure that associates with frame 10 comprises right and left channels 40 R, 40 L. Each channel has an interior bounded by a respective horizontal wall 42 R, 42 L that is disposed against the respective bottom flange 30 R, 30 L of the respective side rail 22 , 24 . Each channel 40 R, 40 L further comprises a respective inner vertical flange 44 R, 44 L and a respective outer vertical flange 46 R, 46 L. Each inner and outer flange pair extend upward from the respective horizontal wall 42 R, 42 L. The inner flanges are disposed against free ends of the flanges of the side rails, and the outer flanges are disposed against the outer faces of the vertical walls of the side rails. [0032] A pair of substantially incompressible fillers 48 R, 50 R fill the channel interior of frame side rail 22 at opposite ends of module channel 40 R. The fillers are disposed between the inner vertical flange of the respective module channel and the vertical wall of the respective side rail. A pair of substantially incompressible fillers 48 L, 50 L fill the channel interior of frame side rail 24 at opposite ends of module channel 40 L. They too are disposed between the inner vertical flange of the respective module channel 40 L and the vertical wall of the respective side rail 24 . [0033] At lengthwise ends of the module, two bridges 52 , 54 span the space between the axle module channels 40 R, 40 L to join those channels together. Each bridge comprises a respective flat horizontal wall 52 H, 54 H and a respective flat vertical wall, 52 V, 54 V. Each horizontal wall 52 H, 54 H joins with each module channel at the junction of the channel's inner vertical flange and the channel's horizontal bottom wall. Each vertical wall 52 V, 54 V joins with the module channels and with the corresponding horizontal wall. The joints are made by welding each horizontal/vertical wall pair together and to the inner vertical flanges of the module channels. [0034] At the location of each filler, a respective fastener comprising a bolt 56 , a steel spacer 57 , and a nut 58 fastens the module to the frame. Spacer 57 has an outer perimeter, preferably circular, that fits as closely as manufacturing tolerances will allow, to a circular through-hole 59 in the respective inner vertical flange, 44 R, 44 L. At its center, spacer 57 has a circular through-hole 61 . [0035] The threaded shank of each bolt 56 passes through through-hole 61 and aligned horizontal through-holes 63 , 65 , and 67 respectively in the respective filler, in the vertical wall of the respective side rail, and in the outer vertical flange of the respective module channel to protrude beyond the latter. A nut 58 is threaded onto the protruding end of the bolt shank and tightened to cause the fastener to fasten the module channel, the side rail channel, and the filler together in horizontal compression. [0036] Spacer 57 has two important structural functions: 1) it allows the fastener (nut and bolt) to horizontally compress the filler, the vertical wall of the frame rail and the outer vertical flange of the module channel; while 2) constraining the fastener against two dimensional motion in a vertical plane parallel to the lengths of the side rails because it is dimensioned to have as close a fit as possible in hole 59 . These functions allow the frame rails to be forced against the outer flanges of the module channels free of interference by the inner flanges of the module, while the close fit of the spacer outer perimeters to the through-holes in the inner flanges constrains the inner flanges from movement in the planes of the spacers. It is to be appreciated that the fastening could be reversed by providing the through-holes to which the spacers fit in the outer flanges of the module channels and forcing the side rails and fillers against the inner vertical flanges of the module channels. [0037] The module channels, the frame side rails, and the fillers are dimensioned to have close fits that are as close as tolerances will allow, thereby creating what is essentially immovable attachment of the module to the frame with the module properly aligned to the centerline of the frame. Because the axles are pre-aligned with the module channels during fabrication of the module, the association of the module channels with the side rails and their subsequent fastening secures proper axle alignment in the vehicle chassis. [0038] Apart from securing desired axle alignment to the frame, the sub-frame also functions as a cross member of the frame, imparting rigidity to the frame with a significantly smaller number of parts and fastening operations when compared with commonly manufactured frames. Only four fasteners are used in the illustrated embodiment. [0039] Fillers 48 R, 48 L have through-holes 60 running lengthwise of the frame side rails to provide passage for one or more of electrical, fluid, and pneumatic lines through them. [0040] While the relationship of the modular axle assembly to the frame provides efficient assembly of the module to a truck chassis, it also provides for efficient disassembly of electrical, fluid, and pneumatic lines for service when needed. The invention permits rapid rear module changes by authorized service centers, interested in offering rebuilt rear module cores. The inventors have further recognized that this capability also provides module interchangeability, and as such can offer new business opportunities to truck manufacturers and truck dealers as explained by the following example. [0041] If a manufacturer or dealer has an existing truck in its inventory that would meet a prospective customer's need except for its particular drive axle, the truck can be quickly adapted to meet the customer's requirement by replacing the rear drive axle module with one that does meet the customer's needs. To accomplish this, different module models are stocked in inventory, either on a manufacturer's or dealer's premises or in a warehouse from which the appropriate module can be quickly delivered to the manufacturer or dealer. [0042] An existing module on a truck is removed simply by elevating the rear end of the chassis, disconnecting the drive shaft coming from the transmission, disconnecting various lines, conduits, etc. so that they do not interfere with the module, removing the fasteners while supporting the module, and then lowering module so that the module channels 40 R, 40 L are clear of the frame side rails 22 , 24 . The module is then moved out of the way. [0043] The replacement module is positioned underneath the elevated rear of the chassis, and from there it is elevated to fit its channels to the frame side rails, or else the chassis is lowered onto the module. The fasteners are re-installed, the driveshaft is re-connected, and other connections made as necessary. With the replacement module installed, the rear of the truck is lowered, and the truck is ready to be driven. [0044] Consequently, the ability to quickly adapt a truck in this way can enable a manufacturer or dealer to make a sale or lease that it otherwise would not. The customer benefits by not having to wait for a new truck to be built at an assembly plant. Customers may wish to purchase more than one rear axle module when investing in a highway tractor. This will permit them to accommodate various work tasks with the same tractor by changing modules. [0045] While a presently preferred embodiment of the invention has been illustrated and described, it should be appreciated that principles of the invention apply to all embodiments falling within the scope of the following claims.	A rear axle/suspension module ( 18 ) is associated with a chassis frame ( 10 ) in a way that facilitates installation and removal to provide more efficient assembly plant operations with fewer parts and less floor space. Also provided is a method of re-equipping a truck that has one particular model of drive axle and suspension module with a different model.	8
BACKGROUND OF THE INVENTION 1. Field of the Invention The subject matter of the present invention pertains to a joystick apparatus for developing electrical signals representative of the location of a point in a two-dimensional coordinate system. 2. Description of the Prior Art A joystick apparatus develops a first and a second electrical signal indicative of the location of a point in a two-dimensional coordinate system. The joystick apparatus includes a movable joystick fixed at one end and angularly movable with respect to said one end thereof, the angular position of the joystick with respect to a vertical line defining the point in the two-dimensional coordinate system, the joystick apparatus developing the electrical signals representative thereof. The joystick apparatus is typically used in conjunction with a cathode-ray tube (CRT) display and a digital computer to enter graphic data displayed on the CRT into the digital computer. The joystick apparatus of the prior art contained an excessively high number of component parts. In addition, the joystick apparatus was non-rebuildable. As a result, a high number of rejects resulted. Furthermore, when the joystick is parallel to the vertical line, the first and second electrical signals generated from the joystick apparatus should be zero, and the point should represent the origin of the two-dimensional coordinate system. However, when the joystick of the prior art was approximately parallel to the vertical line, non-zero electrical signals were developed. Therefore, the resultant point did not represent the origin of the two-dimensional coordinate system. In response to the non-zero electrical signals, the resultant point drifted in the two-dimensional coordinate system. SUMMARY OF THE INVENTION It is a primary object of the present invention to provide a joystick apparatus devoid of the discrepancies and the disadvantages associated with the joystick apparatus of the prior art. It is another object of the present invention to provide a joystick apparatus having a minimum number of component parts associated therewith. It is still another object of the present invention to provide a joystick apparatus including a compensating apparatus designed to compensate for, and thereby eliminate, the drift problem associated with the joystick apparatus of the prior art. These and other objects of the present invention are accomplished by developing a joystick apparatus comprising a first potentiometer and a second potentiometer for developing said first and second electrical signals therefrom, a single bracket interconnected between the first and second potentiometers, and a joystick connected to the base of one potentiometer. The single bracket is interconnected between the first and second potentiometers in a unique manner such that movement of the joystick along one axis will impart a rotational movement to the shaft of one potentiometer but will not impart a rotational movement to the shaft of the other potentiometer. Similarly, movement of the joystick along an axis orthogonal to said one axis will impart a rotational movement to the shaft of the other potentiometer but will not impart a rotational movement to the shaft of said one potentiometer. As a result, the shafts of the potentiometers are used as bearings for the joystick apparatus. The number of component parts have therefore been reduced. In addition, the joystick apparatus further comprises a compensating apparatus for receiving said non-zero electrical signals from the potentiometers when the joystick is approximately parallel to the vertical line, and for developing electrical signals therefrom which are approximately equal to zero. As a result, said resultant point no longer drifts in the two-dimensional coordinate system. Further scope of applicability of the present invention will become apparent from the description given hereinafter. However, it should be understood that the details of the description and the specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from the detailed description. BRIEF DESCRIPTION OF THE DRAWINGS A full understanding of the present invention will be obtained from the detailed description given hereinbelow and the accompanying drawings, which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: FIGS. 1-2 illustrate the prior art joystick apparatus; FIGS. 3A-3B illustrate the joystick apparatus of the present invention; FIG. 4 illustrates a return spring mechanism utilized in conjunction with the joystick apparatus of the present invention to maintain the joystick at an angular position approximately parallel to the vertical line in order to minimize the drift problem associated with the joystick apparatus of the prior art; FIG. 5 illustrates an electrical circuit apparatus designed to cancel the non-zero electrical signals generated from the first and second potentiometers thereby eliminating the drift problem associated with the joystick apparatus of the prior art; and FIG. 6 illustrates an alternative embodiment of the invention relative to FIG. 3A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, a joystick apparatus of the prior art is illustrated. In FIG. 1, a pair of potentiometers 10 and 12 are mounted on a common frame 14 and a common control stick 16 (a joystick) controls both potentiometers 10, 12. One end of the control stick 16 is mounted on a stationary member by a universal joint, thereby allowing the other end of the control stick 16 to rotate in both the X and the Y directions. The control shafts of the potentiometers 10 and 12 are coupled to the control stick 16 by respective arm members 18 and 20, the arm members including elongated opening 22 and 24, respectively. Potentiometer 10 is controlled by rotating the control stick 16 in the X direction. Control stick 16 may be rotated in any desired direction to control both potentiometers, 10 and 12, simultaneously. The operation of the joystick shown in FIG. 1 may be illustrated, electrically, in FIG. 2. In FIG. 2, the fixed terminals of each potentiometer 10, 12 are connected between positive and negative voltage sources, e.g., between ±12 volts. The output voltages on the sliders are connected to output terminals 30, 32 via respective voltage followers 26, 28. The output voltages present at output terminals 30, 32 are supplied to both orthogonal deflection means of a cathode-ray tube (CRT) for deflecting the electron beam generated within said tube to a selected coordinate on the CRT screen, the selected coordinate being defined by the angular position of the control stick 16 (the joystick) shown in FIG. 1. One of the major disadvantages of the joystick apparatus shown in FIG. 1 is the large number of component parts associated therewith. As a result, the overall size of the joystick apparatus was excessively large. This disadvantage has been eliminated by virtue of the joystick apparatus of the present invention, shown in FIG. 3A. In FIG. 3A, a joystick apparatus of simple construction and small size is illustrated, having a low number of component parts associated therewith. FIGS. 3A and 3B illustrate, respectively, top and front views of the joystick apparatus of the present invention. A first potentiometer 34 includes a control shaft 36 mounted on a frame 38. An L-shaped arm 40, the single bracket, is mounted on the control shaft 36 at the short leg portion thereof. A second potentiometer 42 includes a control shaft 44 mounted near the free end of L-shaped arm 40. The second potentiometer 42 includes a stick base 46 extending from and being connected to the body of the second potentiometer 42. A control stick 48 is mounted on said stick base 46. Return spring mechanisms RS1 and RS2 are mounted on shafts 36 and 44 in order to return the control stick 48 to a perpendicular, center position when the control stick 48 is released. One example of a return spring mechanism (RS1 or RS2) is shown in detail in FIG. 4. In FIG. 4, a pair of return leaves 50, 50' are mounted on a potentiometer shaft (either 36 or 44), the return leaves 50 and 50' functioning as a pair of scissors. Return spring 52 is connected between the end portions of return leaves 50, 50'. A pair of fixed projections 54 and 56 are mounted, respectively, on the L-shaped arm 40 and on the frame 38, at different radial distances from potentiometer shaft (36 or 44). Fixed projections may also be mounted on the stick base 46 in lieu of the free end of arm 40. The joystick apparatus shown in FIGS. 3A, 3B and 4 operates in the following manner: when the control stick 48 is rotated in the vertical (Y) direction, the body of the second potentiometer 42 rotates with respect to its shaft 44. The shaft 36 of the first potentiometer 34 does not rotate. The angle between the two projections 54 and 56 increases as control stick 48 is rotated from the perpendicular, center position in either direction. An increase in said angle between the two projections increases the angle between the return leaves 50, 50' associated with spring mechanism RS2, to thereby stretch return spring 52. It is, therefore, understood that control stick 48 returns to the perpendicular center position when control stick 48 is released. On the other hand, when the control stick 48 is rotated in the horizontal (X) direction, L-shaped arm 40 and the second potentiometer 42 will rotate as an integral part thereof. A rotation of the control stick 48 in the horizontal (X) direction will rotate the shaft 36 of the first potentiometer 34. The return spring mechanism RS1 operates to stretch its spring 52. The second potentiometer 42 in respect to its shaft 44 remains unrotated in this condition. When the control stick 48 is released, the L-shaped arm 40 and the second potentiometer 42 are returned to their original position. The control stick 48 therefore returns to its perpendicular, center position. It should be understood that control stick 48 may be rotated freely in any desired direction, other than the X or Y direction. In such a case, the return springs 52 associated with both return spring mechanisms RS1 and RS2 are stretched. As a result, when the control stick 48 is released, the stretched return springs 52 associated with return spring mechanisms RS1 and RS2 force the control stick 48 to return to the perpendicular, center position. When the control stick 48 is released, it should return to the perpendicular center position. Zero volts should appear on the slider of potentiometers 34 and 42. However, when the control stick 48 is released, the return spring mechanisms RS1 and RS2 may not always return the control stick 48 to exactly its perpendicular, center position. Therefore, a non-zero voltage may appear on the slider of potentiometers 34 and 42, and, as a result, a position error may result. This position error causes the drift problem associated with the joystick apparatus of the prior art. FIG. 5 illustrates electrical means for effectively compensating for and thereby eliminating such position error. In FIG. 5. the output potential from each of the first and second potentiometers 34 and 42 are applied to the non-inverting input terminal of an operational amplifier 58 and 58'. A controllable potential from an additional compensation potentiometer 62 and 62' is supplied through resistors R 1 and R 1 ' to the inverting input terminal of amplifier 58 and 58' including feedback resistors R 2 and R 2 ' between the output and inverting input terminals thereof. In operation, assume that the joystick (control stick) 48 is in the perpendicular, center position, and, an error voltage lying in a range between ±300 mV and ±12 volts is applied to the non-inverting terminal of amplifiers 58 and 58'. R 1 and R 2 may be chosen to be 40K and 1K, respectively. For example, an error voltage approximately equal to ±300 mV may appear at the non-inverting input terminal of amplifiers 58 and 58'. As a result, the error voltage will appear at the inverting input terminal of amplifiers 58 and 58' because of attenuation by the resistive divider network R 1 -R 2 (or R 1 '-R 2 '). The voltage gain of the amplifiers 58 and 58' is 1.025 or essentially equal to unity. By adjusting potentiometers 62 and 62', the output voltage appearing at the output terminal of amplifiers 58 and 58' may be adjusted to be approximately equal to zero. Referring to FIG. 6, a further refinement to the embodiment of invention shown in FIG. 3A is illustrated. In FIG. 6, the L-shaped arm 40 shown in FIG. 3A has been extended to include an additional L-shaped arm 40A. The short leg portion 40A1 of the additional L-shaped arm 40A is pivotally secured to an additional frame 38A via an additional shaft 36A. This construction of the joystick apparatus shown in FIG. 6 provides said apparatus with a greater rigidity and reliability when the joystick 48 of said apparatus is rotated in the horizontal (X) direction. As is understood from the foregoing description, the joystick apparatus according to the present invention features a very simple mechanical construction. This is mainly due to the fact that the shafts 36 and 44 of the first and second potentiometers 34 and 42 function as the bearings of the joystick apparatus. This use of the shafts as bearings reduces the mechanical tolerance of the joystick apparatus. Furthermore, the conventional complicated mechanical mechanism associated with the joystick apparatus of the prior art has been replaced by a simple electrical circuit. This permits the use of a low cost, simple, joystick apparatus, the joystick apparatus of the present invention. The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spririt and scope of the invention and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.	A joystick apparatus is disclosed having a minimum number of component parts associated therewith. The joystick apparatus comprises a first potentiometer, a second potentiometer, a bracket interconnected between the shafts of said first and second potentiometers, and a joystick connected to the base of one of the potentiometers. The bracket is interconnected between the shafts of the first and second potentiometers in a manner such that a movement of the joystick along one axis will impart a rotational movement to the shaft of one potentiometer, but will not impart a rotational movement to the shaft of the other potentiometer.	8
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reversible plow that can be pivotally shifted to selectively provide furrows that have the loosened earth deposited on either the right side or the left side of the center of the furrow. More particularly, the invention relates to a reversible plow that is vertically adjustable, relative to the plow draw beam, to permit variation of the angle that the plow structure makes relative to the ground, in order to selectively permit deep, medium deep, normal, and shallow plow depths. 2. Description of the Related Art Various types of reversible plow structures have been developed over the years. Two examples of such structures are shown in U.S. Pat. No. 90,895, which issued Jun. 1, 1869, to W. H. Tyler, and in U.S. Pat. No. 291,503, which issued Jan. 4, 1884, to H. Gates. Each of the Tyler and Gates patents shows a reversible plow in which the reversible plow support structure is fixed in position relative to the draw beam, and the pivot axis of the plow remains fixed in a substantially horizontal position. Consequently, control of the depth of the plowing operation is achieved by upward or downward pressure applied to the plow handles by the operator. Structures for permitting changing the angle of the plow structure relative to the plow draw beam are shown in U.S. Pat. No. 490,276, which issued Jan. 24, 1893, to D. B. English; U.S. Pat. No. 1,105,264, which issued Jul. 28, 1914, to D. H. Floyd; and U.S. Pat. No. 1,157,399, which issued Oct. 19, 1915, to W. A. Kimbell. Although patents directed to plow structures have issued since the mid-19th century, it is believed that the combination of a reversible plow with plow support structure to permit selective vertical adjustment of the plow angle relative to the ground, is novel. Such a structural arrangement is highly advantageous in that the ability to vertically adjust the plow to change the angle at which the plow passes through the earth permits the plow orientation to be adapted to the extent of compaction and density of the soil, thereby providing a more versatile plow. It is therefore an object of the present invention to overcome the shortcomings of the prior art structures and to provide an improved plow that provides in a unitary structure both reversible operation as well as vertical adjustment. SUMMARY OF THE INVENTION Briefly stated, in accordance with one aspect of the present invention, a reversible plow is provided that is carried by a plow beam having a beam longitudinal axis, the beam connected with a suitable traction means for pulling the plow, which normally would be one or more draft animals. The plow includes a plow frame, and a plow assembly having a pair of first and second plow share and mold board assemblies pivotally carried on a plow pivot axis extending from and supported by the frame. The pivotal arrangement of the plow share and mold board assemblies permits selective presentation in an operative position of one of the first and second plow share assemblies, as selected by the operator. A pivoting means is provided for pivoting the plow share and mold board assemblies about the pivot axis, and stop means are carried by the plow frame for limiting pivotal movement of the plow share and mold board assemblies between first and second positions that are substantially 180° apart. The plow frame is connected with the plow beam by a connecting means that includes a plow frame pivot axis positioned above the beam longitudinal axis and extending in a generally horizontal direction. A plow frame positioning means is positioned above the beam longitudinal axis and forwardly of the plow frame pivot axis for positioning the plow frame at one of a plurality of positions above the plow beam, the positioning means permitting the forward end of the plow frame to be secured at a desired position above the plow beam to vary the angle and depth of penetration of the plow share relative to the ground, and thereby the depth of the resulting furrow. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side perspective view of a reversible plow in accordance with the present invention, showing in dashed lines the several positions at which the plow can be oriented relative to the beam. FIG. 2 is a side view of the plow shown in FIG. 1, after the plow has been rotated 180° and with the plow shares and mold boards shown in dashed lines. DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, and particularly to FIG. 1 thereof, there is shown a plow 10 that is connected with a plow draw beam 12, only a portion of which is shown in the drawings. As will be appreciated by those skilled in the art, the beam extends in a forward direction to a yoke (not shown) or the like, to permit draw beam 12 to be carried by one or more draft animals (not shown) that provide the pulling power for drawing the plow through the soil. Plow 10 is a reversible structure that is pivotally carried by a plow frame 14, which includes a sharpened forward edge to cut through sod and earth, and which also includes a plow pivot axis 16 that extends in a rearward direction relative to draw beam 12. Pivot axis 16 supports a first plow assembly 17 that includes a moldboard 18 that is curved in order to cause loosened earth or sod to be lifted and turned over the adjacent earth during the plowing operation. Moldboard 18 extends upwardly and downwardly from pivot axis 16 and is connected to and terminates in a pair of spaced plow shares 20, such as by means of bolts 22, or the like. Plow shares 20 each include a lip 21 that extends forward of plow share edge 23, and is bent inwardly, to deflect any grass from sod that tends to creep along edge 23, to prevent formation of a gap between moldboard 18 and plow frame 14, and also reduce the drag that would otherwise be imposed by any grass or sod that tends to collect there. Adjacent the lowermost plow share 20 is positioned a penetrator 24 that is carried in a penetrator sleeve 25 (see FIG. 2) that is welded to plow frame 14. Penetrator 24 includes a forwardly extending pointed end 26 for penetrating the earth to facilitate the plowing operation. Additionally, penetrator 24 also includes an upwardly facing surface 27 that is inclined to the longitudinal axis of the penetrator to cause a downwardly directed force to be continuously applied to penetrator 24 as it is drawn through the earth, to keep the penetrator from riding upwardly during a plowing operation. Positioned on the opposite side of plow pivot axis 16 from first plow assembly 17 is a second plow assembly 28 that is similarly structured and configured. However, plow assembly 28 is adapted to deposit the earth and sod on the right side of the plow structure during plowing operations, whereas first plow assembly 17 is adapted to deposit the earth and sod on the left side of the plow structure during plowing operations. A stop means 30 is carried on and extends upwardly from plow frame 14 for limiting rotational movement of plow assemblies 17 and 28 relative to plow frame 14. As shown in FIG. 1, stop means 30 includes a stop ring 32 and an upwardly extending stop arm 34, the stop ring and arm being adapted to be pivoted as an assembly about a substantially horizontally extending pivot axis defined by stop ring connecting bolt 36 that passes through both a lateral extension forming part of stop ring 32 and an aperture (not shown) in plow frame 14. A coulter 38 is provided at a point forward of plow pivot axis 16 and below stop means 30. Coulter 38 is carried by plow frame 14 and is secured thereto by means of a coulter clamp 40, which is connected to plow frame 14 by bolt 36. Coulter 38 is a wheel that is rotatably carried by coulter spring 42 and includes a plurality of spaced, sharpened peripheral edges 44 and a series of intermediate scalloped recesses 46 which permit edges 44 to cut into the earth ahead of the plow, as will be appreciated by those skilled in the art. Plow frame 14 includes a curved section 48 extending from pivot axis 16 in a generally forward direction, a first linear portion 50 extending forwardly of curved portion 48, and a second linear portion 52 extending forwardly of first linear portion 50. Linear portions 50 and 52 are not coaxial and their longitudinal axes are positioned to define an included angle of about 175°. Adjacent the rearmost end of linear portion 52 is an aperture (not shown) through which a carrier pivot pin 54 extends to define a generally horizontal pivot axis about which plow frame 14 is pivotable. Carrier pivot pin 54 is spaced above the upper surface of draw beam 12 and is carried in a U-shaped pivot support 56 that includes a pair of horizontally opposed openings (not shown) to receive carrier pivot pin 54. Support 56 is secured to a base plate 58, such as by welding, and base plate 58 is, in turn, secured to draw beam 12, such as by bolts 60, or the like. Positioned on base plate 58 forwardly of carrier pivot pin 54 is adjustment support 62, which is also a U-shaped member that is secured to base plate 58, such as by welding. Adjustment support 62 includes a pair of spaced, parallel legs that extend generally vertically, relative to draw beam 12, and that each include respective pairs of opposed openings 64 to receive a carrier position bolt 66. As shown, four such openings 64 are provided in each leg of adjustment support 62, although more or fewer such openings can be provided, if desired. The purpose of the several openings 64 in adjustment support 62 is to permit vertical adjustment of plow 10, relative to draw beam 12, as will be hereinafter described in greater detail. Referring now to FIG. 2, plow pivot axis 16 includes a pair of spaced saddles 70 that are positioned on either side of a sleeve 71 that is secured to moldboard support rib 73 and that permits plow 10 to pivot about pivot axis 16. Support rib 73 is positioned on the outside surface of the moldboard and extends between the respective plow shares 20. Extending from pivot axis 16 in a generally upward and rearward direction is a handle arrangement 72. Pivot axis 16 also carries a pivotable locking bar 74 that extends substantially parallel with handle 72. Locking bar 74 includes a leg 76 that extends in a generally downward direction to pivotally support a lock bolt 78 that is slidably received in a pair of lock bolt guide channels 80 and a locking clip 82. Locking bar 74 is pivotable about a locking bar pivot axis 84, and when locking bar 74 is moved in an upward direction shown by arrow A, leg 76 causes lock bolt 78 to be drawn in a rearward direction as generally illustrated by arrow B. When lock bolt 78 is fully withdrawn from locking clip 82 rearwardly to the forwardmost of guide channels 80, plow 10 can be pivoted about plow pivot axis 16 to present the opposite plow share and moldboard structure 28 for the next plowing operation. As also seen in FIG. 2, penetrator 24 is slidably carried in a penetrator housing 25, to permit penetrator 24 to be removably carried by the plow structure. As shown, penetrator 24 includes forwardly facing pointed end 26 and also a rearwardly facing pointed end 90. Housing 25 is a tapered structure having a narrowed forward end to slidably receive penetrator 24, and a diverging rearward end. Adjacent the rearward end of housing 25 and offset from each other are a pair of penetrator support plates 89 and 91 that extend inwardly toward the penetrator to contact the upper and lower surfaces, respectively, of penetrator 24. Preferably, support plates 89 and 91 are not secured along each of their edges to penetrator housing 25 so that they have a slight amount of flexibility to permit penetrator 24 to be securely gripped. A wedge member 92 is provided to fit between the upper surface of penetrator 24 and the lowermost edge of support plate 89 to securely retain the penetrator in position. A retaining chain 94 extends from wedge member 92 and is connected with a retaining link 96 carried by plow frame 14. Consequently, the penetrator can be removed and reinserted in the opposite direction to present a new penetrator tip when the original one becomes dull. Penetrator housing 25 includes a lower surface that carries a sole plate 95 that is riveted to housing 25 by rivets 97. When sole plate 95 is eroded away by the earth, rivets 97 can be removed to permit a new sole plate to be attached. The plow is operable in the usual manner, except that the vertical adjustment of the plow body 10 can be changed by selecting the desired positioning openings 64 in adjustment support 62. Preferably, openings 64 on each side of adjustment support 62 are spaced from each other to provide carrier beam angles between second linear portion 52 and draw beam 12 of from about 21° to about 34°. By virtue of the adjustment provided, the angular orientation of the plow body relative to the ground can change, to selectively provide four plowing depths: deep, medium deep, normal, and shallow. However, regardless of the angular position of second linear portion 52, the pulling line of the plow beam is maintained constant and is substantially centered relative to the center of the moldboard, which is always the center of load, whether plowing deep or shallow. By maintaining the pulling power line of the draft beam constant, there is little or no change in the power demand, regardless of the angular orientation of the plow. It can therefore be seen that the present invention provides distinct advantages over the prior art plow structures. Although particular embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit of the present invention. It is therefore intended to encompass within the appended claims all such changes and modifications.	A rotatable plow that includes a pair of oppositely disposed plow members carried on a plow carrier pivotally carried by a draft beam. The draft beam includes a plow carrier adjustment yoke for changing the angular orientation of the plow frame relative to the ground, and thereby also the plow members. A locking arrangement is provided to permit the plow frame to be locked in a predetermined position to selectively present one of a first and a second second plow and moldboard assembly for conducting plowing operations.	0
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] Not Applicable STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH [0002] Not Applicable BACKGROUND OF THE INVENTION [0003] The use of stents, and other implantable medical devices such as grafts, stent-grafts, vena cava filters, etc, hereinafter referred to cumulatively as stents, to maintain the patency of bodily lumens is well known. [0004] Stents are typically delivered via a catheter in an unexpanded configuration to a desired bodily location. Once at the desired bodily location, the stent is expanded and implanted in the bodily lumen. [0005] Typically, a stent will have an unexpanded (closed) diameter for placement and an expanded (opened) diameter after placement in the vessel or the duct. Some stents are self-expanding; some stents are expanded mechanically with radial outward force from within the stent, as by inflation of a balloon; and some stents, known as hybrid stents, have one or more characteristics common to both self-expanding and mechanically expandable stents. [0006] An example of a mechanically expandable stent and associated delivery system is shown in U.S. Pat. No. 4,733,665 to Palmaz, which issued Mar. 29, 1988, and discloses a number of stent configurations for implantation with the aid of a catheter. The catheter includes an arrangement wherein a balloon inside the stent is inflated to expand the stent by plastically deforming it, after positioning it within a blood vessel. [0007] A type of self-expanding stent is described in U.S. Pat. No. 4,503,569 to Dotter which issued Mar. 12, 1985, and discloses a shape memory stent which expands to an implanted configuration with a change in temperature. Self-expanding stents are constructed from a wide variety of materials including nitinol, spring steel, shape-memory polymers, etc. [0008] In many stent delivery systems, particularly those used to deliver a self-expanding stent, the stent is typically retained on the catheter via a retention device such as a sheath. The stent may be deployed by retracting the sheath from over the stent. To prevent the stent from being drawn longitudinally with the retracting sheath, many delivery systems provide the catheter shaft with one or more bumpers or hubs. [0009] However it is known that in many cases when a sheath is withdrawn from a stent, particularly a self-expanding stent constructed of shape memory material, the stent may be displaced longitudinally relative to the catheter shaft as a result of so-called “stent jumping,” wherein when a sleeve or sheath is withdrawn from the stent during delivery the stent frictional forces and stent constrainment forces exerted by the retracting sleeve on the stent are less than those of the stent expansion force at an angle exiting the stent delivery system. As a result, in some instances, as the sheath is withdrawn from about the stent, the stent will tend to migrate or “jump” longitudinally relative to the stent mounting region of the catheter resulting in the imprecise delivery of the stent and/or distortion of the stent body. Because a portion of the stent is already expanding beyond the diameter of the catheter when stent jumping typically occurs, the presence of one or more hubs on the catheter shaft will typically not prevent stent jumping. [0010] It would thus be desirable to provide a stent delivery system and/or one or more components thereof which may reduce or eliminate occurrences of stent jumping in order to improve the accuracy of stent placement within a vessel or other body space. [0011] All US patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety. [0012] Without limiting the scope of the invention a brief summary of some of the claimed embodiments of the invention is set forth below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below. [0013] A brief abstract of the technical disclosure in the specification is provided as well only for the purposes of complying with 37 C.F.R. 1.72. The abstract is not intended to be used for interpreting the scope of the claims. BRIEF SUMMARY OF THE INVENTION [0014] The present invention is directed to several embodiments which seek to improve the accuracy of stent placement and reduce the occurrence and severity of stent jumping. [0015] For example, in at least one embodiment, the invention is directed to a stent delivery system that reduces the potential for stent jumping by providing one or more protrusions to which the stent, or one or more portions thereof, may be temporarily engaged during retraction of a stent retaining sleeve or sheath. The protrusions do not interfere with the radial expansion of the stent but will prevent the stent from moving longitudinally relative to the catheter. [0016] In some embodiments, the invention is directed to one or more bands or collars, that may be disposed about the catheter under the stent. Bands may be provided with a variety of surface features such as bumps, flaps, tabs, fins or other protrusions or surface features, against or about which a portion of the stent may be temporarily engaged. In at least one embodiment the bands are radiopaque. In some embodiments the a band is positioned adjacent to or at least partially under an end of the stent to allow the surface features of the band to engage the end affects of the stent while the remaining portion of the stent is freed to expand. In at least one embodiment, a stent is provided with one or more end regions which define a relatively large opening or gap in the stent structure to engage the surface features of an engagement band catheter shaft. [0017] These and other embodiments which characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages and objectives obtained by its use, reference should be made to the drawings which form a further part hereof and the accompanying descriptive matter, in which there is illustrated and described embodiments of the invention. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) [0018] A detailed description of the invention is hereafter described with specific reference being made to the drawings. [0019] [0019]FIG. 1 is a perspective view of an embodiment of the invention. [0020] [0020]FIG. 2 is a perspective view of the embodiment shown in FIG. 1 wherein the band defines an alternative pattern of surface features. [0021] [0021]FIG. 3 is a partial side view of a stent retaining region of a stent delivery catheter with the band of FIG. 1 positioned thereon and engaged to a portion of a stent. [0022] [0022]FIG. 4 is a perspective view of the band of FIG. 1 wherein the surface features are provided by cutting and folding selected portions of the band. [0023] [0023]FIG. 5 is a perspective view of the embodiment of FIG. 1 wherein the surface features are tabs. [0024] [0024]FIG. 6 is a cross-sectional view of the embodiment of FIG. 1 wherein the surface features are substantially fin shaped. [0025] [0025]FIG. 7 is a partial side view of the embodiment shown in FIG. 2 wherein at least a portion of the stent defines an enlarged opening for engaging the band. [0026] [0026]FIG. 8 is a cross-sectional side view of an embodiment of the invention. [0027] [0027]FIG. 9 is a cross sectional side view of the embodiment of FIG. 8 shown during stent delivery. [0028] [0028]FIG. 10 is a cross sectional side view of the embodiment of FIGS. 8 and 9 shown after the stent is fully deployed. DETAILED DESCRIPTION OF THE INVENTION [0029] While this invention may be embodied in many different forms, there are described in detail herein specific preferred embodiments of the invention. This description is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiments illustrated. [0030] For the purposes of this disclosure, like reference numerals in the figures shall refer to like features unless otherwise indicated. [0031] As mentioned above the present invention is embodied in a variety of forms. For example, in the embodiment shown in FIG. 1 the invention is embodied in a stent retaining band or collar, indicated generally at 10 , which has an outer surface 12 comprising one or more protrusions 14 . As illustrated by FIGS. 1 and 2 the protrusions 14 may have similar or differing dimensions and orientations relative to one another. In addition, the protrusions 14 may be arranged or positioned on the outer surface 12 by columns, rows, or any other pattern desired. [0032] As is shown in FIG. 3, the pattern of protrusions 14 is determined, at least in part, based on the geometry of the stent 26 to which the protrusions 14 are designed to engage. As is shown, band 10 is constructed and arranged to be mounted on the shaft 16 of a catheter 18 . The band is positioned on a stent retaining portion 20 of the shaft 16 . Typically the band 10 is positioned such that one or more of the protrusions 14 pass at least partially through one or more of the openings 22 defined by the tubular wall 24 of a stent, stent-graft, graft, filter or other implantable medical device, hereinafter referred to collectively as a stent 26 or stents. [0033] A band 10 may be positioned underneath one or both ends 30 of the stent 26 , or any other portion of the stent desired. In some embodiments the band 10 may have a length equal to or greater than the length of the stent 26 . [0034] The protrusions 14 extend at least partially through the openings 22 to engage the portions or struts 28 of the stent 26 immediately adjacent thereto. In addition to, or as an alternative to positioning the protrusions 14 through one or more of the stent openings 22 , in some embodiments the protrusions 14 may be positioned adjacent to one or both of the ends 30 of the stent 26 . [0035] In some embodiments of the invention, a stent 26 is provided with ends 30 whose struts 28 have been constructed to provide openings 22 which are enlarged or otherwise modified in order to more readily accommodate the positioning of the protrusions 14 therein. [0036] In the various embodiments shown and described herein, the band 10 may be at least partially radiopaque so that the band 10 may be utilized as a marker band on a stent delivery catheter 18 such as is shown in FIGS. 3 and 8- 10 . [0037] Band 10 may be constructed of a wide variety of materials including but not limited to metals, plastic, rubber, silicone, polymers, etc. Where the band 10 is at least partially constructed of metal, in at least one embodiment the metal is a radiopaque metal such as platinum, gold, iridium, etc. In at least on embodiment the metal is a biocompatible metal such as including but not limited to stainless steel, nitinol, cobalt and alloys thereof. Some polymer materials suitable for use in construction of the band 10 include one or more polyetheramide block copolymers, such as the ester linked polyetheramides sold under the trade mark PEBAX®; polyetherester block copolymer such as sold under the ARNITEL® and HYTREL®; nylon, polyethylene, etc. [0038] The protrusions 14 may be constructed of the same or different material as the rest of the band or band body 15 . [0039] As indicated above the protrusions 14 may be of any shape or configuration. For example in the embodiments shown in FIGS. 1-2 the protrusions are raised portions or bumps on the surface 12 of the band and may be formed by a variety of forming mechanisms including for example molding the band and protrusions into the shape shown. In some embodiments the protrusions 14 may be made from altering the inner shaft 16 to homogeneous with the material of the band 10 . Protrusions 14 may also be separate elements which are welded, stamped, punched, adhesively engaged, injection molded, melted or otherwise positioned and/or engaged onto the surface 12 of the band 10 . However, as is shown in FIG, 4 , protrusions 14 may also be formed by cutting out one or more openings 40 into the band 10 . The material or flap 42 cut from the tube 10 remains integral and engaged to the tube 10 along at least one line or point of engagement 44 . The resulting flap 42 of tube material is oriented to extend at least partially outward from the tube surface 12 to act as a protrusion 14 . Where multiple flaps 42 are provided for, flaps 42 may be of any shape desired and may be of a uniform or different configuration relative to one another. [0040] Alternatively, the band 10 may be provided with one or more flaps 42 to act as protrusions 14 without cutting or otherwise providing the band 10 with openings flaps or slots 40 from the band 10 by molding or otherwise shaping the band 10 to include flap style protrusions 14 such as are shown in FIG. 5. [0041] As a result of the plastic or deformable nature of the material of the band 10 , in some cases one or more protrusions 14 may be provided by pinching and or pulling selected portions of the band 10 together and radially outward in order to form one or more substantially fin shaped protrusions 14 such as is shown in FIG. 6. A band 10 may be provided with substantially fin shaped protrusions by manipulating a band 10 in the manner described or by molding or other wise forming the tube 10 with the protrusions already in place. [0042] As indicated above, the shape, size and arrangement of the protrusions of the band are selected in order to temporarily engage at least a portion of a stent when the stent is engaged to the stent retaining area 20 of a delivery catheter. As is shown in FIG. 7, where the band 10 employs flap, fin or other somewhat elongated protrusions 14 , the protrusions are designed to be positioned within the spaces or openings 22 between adjacent struts 28 of the stent 26 . [0043] When a stent delivery catheter 18 , such as is shown in FIG. 8 being advanced through a vessel 50 , is equipped with one or more bands 10 , the one or more protrusions 14 of the bands 10 will engage the stent 26 in the manner described above. [0044] As is shown in FIG. 9, when the catheter 18 has been positioned within the vessel 50 at a desired location, the stent retaining sheath 52 is retracted from the stent retaining area 20 to expose the stent 26 for delivery. In the embodiment shown, the protrusions 14 on the band 10 positioned adjacent to the distal end 56 of the stent 26 , will continue to engage the stent 26 until the sleeve 52 is fully retracted off of the stent 26 , such as is shown in FIG. 10. As a result of the engagement between the protrusions 14 and the stent 26 , the band 10 acts to anchor the stent 26 to the shaft 16 thereby preventing longitudinal jump of the stent 26 relative to the catheter 18 . Thus the stent 26 is deployed from the catheter 18 and into the intended area of the vessel 50 with improved precision and reliability. [0045] The above disclosure is intended to be illustrative and not exhaustive. This description will suggest many variations and alternatives to one of ordinary skill in this art. All these alternatives and variations are intended to be included within the scope of the claims where the term “comprising” means “including, but not limited to”. Those familiar with the art may recognize other equivalents to the specific embodiments described herein which equivalents are also intended to be encompassed by the claims. [0046] Further, the particular features presented in the dependent claims can be combined with each other in other manners within the scope of the invention such that the invention should be recognized as also specifically directed to other embodiments having any other possible combination of the features of the dependent claims. For instance, for purposes of claim publication, any dependent claim which follows should be taken as alternatively written in a multiple dependent form from all prior claims which possess all antecedents referenced in such dependent claim if such multiple dependent format is an accepted format within the jurisdiction (e.g. each claim depending directly from claim 1 should be alternatively taken as depending from all previous claims). In jurisdictions where multiple dependent claim formats are restricted, the following dependent claims should each be also taken as alternatively written in each singly dependent claim format which creates a dependency from a prior antecedent-possessing claim other than the specific claim listed in such dependent claim below. [0047] This completes the description of the preferred and alternate embodiments of the invention. Those skilled in the art may recognize other equivalents to the specific embodiment described herein which equivalents are intended to be encompassed by the claims attached hereto.	A method and apparatus for reducing the longitudinal aspect of the catheter to stent force comprises at least one grip member for use with a stent delivery system. The grip engages a stent in the unexpanded state prior to delivery of the stent by retracting a stent retaining sheath. The grip comprises a body region having an outer diameter, a first end and a second end. The outer diameter of the first end is greater than the outer diameter of the second end. The grip is at least partially constructed from a polymeric material.	0
BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The present invention relates to an anti-pollution structure with a fuel economizing fuel feed and exhaust system for an internal combustion engine. SUMMARY OF THE INVENTION Air from a fan pulley driven air blower is fed to a heat exchanger where a portion of the air is fed to an exhaust burner system and another portion of the air is fed to the air cleaner of the engine carburetor. A third portion of the air is fed to an air injector between the carburetor and the intake manifold so that heated air is supplied to both the air cleaner and to the intake manifold. Venting connections for the engine entrain pollutants in conduits extending to the air injector. The primary object of the invention is to provide an anti-pollution structure with a fuel economizing fuel feed and exhaust system for an internal combustion engine. Other objects and advantages will become apparent in the following specification when considered in light of the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of an engine incorporating the invention; FIG. 2 is a front elevation of the engine of FIG. 1; FIG. 3 is an enlarged fragmentary vertical sectional view, taken along the line 3--3 of FIG. 1 looking in the direction of the arrows; FIG. 4 is a fragmentary horizontal sectional view, taken along the line 4--4 of FIG. 3, looking in the direction of the arrows; FIG. 5 is an enlarged fragmentary vertical sectional view, taken along the line 5--5 of FIG. 1, looking in the direction of the arrows; FIG. 6 is a fragmentary horizontal sectional view, taken along the line 6--6 of FIG. 5, looking in the direction of the arrows; FIG. 7 is a sectional view through a modified valve system used with the invention; FIG. 8 is a top plan view of another engine incorporating the invention; FIG. 9 is an enlarged fragmentary vertical sectional view, taken along the line 9--9 of FIG. 8, looking in the direction of the arrows; FIG. 10 is a fragmentary vertical sectional view, taken along the line 10--10 of FIG. 9, looking in the direction of the arrows; FIG. 11 is an enlarged fragmentary vertical sectional view, taken along the line 11--11 of FIG. 8, looking in the direction of the arrows; FIG. 12 is an enlarged fragmentary vertical sectional view, taken along the line 12--12 of FIG. 8 and of FIG. 13; and FIG. 13 is a vertical sectional view, taken along the line 13--13 of FIG. 12, looking in the direction of the arrows. DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings in detail, wherein like reference characters indicate like parts throughout the several figures, the reference numeral 20 indicates generally an anti-pollution structure with a fuel economizing fuel feed and exhaust system for an internal combustion engine shown generally at 21. The engine 21 is of conventional internal design and includes a combined integral heat exchanger and exhaust manifold 22 having an exhaust burner 23 of the type illustrated in detail in my Patent Number 3,630,031 entitled Anti-Pollution System for Internal Combustion Engines. A blower 24 is mounted on the front of the engine 21 and is driven by fan pulley 25 so as to provide a flow of air under pressure when the engine 21 is operational. An air conduit 26 extends from the blower 24 to the heat exchanger 22 providing a supply of air thereto which is heated therein by exhaust gas flow. The air supplied to the heat exchanger 22 provides the supply of air for the exhaust burners 23 and additionally provides the supply of heated air which flows from the heat exchanger 22 through a conduit 27. The conduit 27 extends to the air cleaner 28 of a carburetor 29 as can be seen in FIGS. 1 and 2. A branch conduit 30 extends from the conduit 27 to a venting air injector 31 positioned between the carburetor 29 and the intake manifold 32. A thermostat control valve 33 is mounted in the line 30 to provide heat control for the air flowing from the heat exchanger 22. A filter 34 in the line 30 prevents dirt from reaching the venting air injector 31. A first throttle valve 35 is mounted in the conduit 30 and has an arm 36 connected to the throttle linkage 37. A vacuum control valve 38 is also positioned in the conduit 30 to regulate the flow of air through the conduit 30 by the vacuum in the intake manifold 32. A conduit 39 extends from the valve chamber 40 through a PCV valve 41 to the conduit 30 to vent the valve chamber 40 and eliminate oil and gas fumes therefrom. A conduit 42 extends from the crank case of the engine 21 through a PCV valve 43 and is connected to the conduit 30 to vent the crank case and eliminate oil fumes therefrom. A conduit 44 extends from the blower 24 to the air cleaner 28 and a branch conduit 45 extends from the conduit 44 to the venting air injector 31. A thermostat valve 33 is positioned in the conduit 45 and a filter 34 filters the air flowing therethrough. A throttle valve 35a is positioned in the conduit 45 and has an idle adjustment screw 35b mounted thereon to maintain an idle adjustment of air flowing through the conduit 45. Linkage 35c is connected to the throttle valve 35a and extends to a piston 35d mounted in a hollow cylinder 35e. The hollow cylinder 35e controls the carburetor throttle valve 35f when the piston 35d has moved to contact the end of hollow cylinder 35e. A vacuum actuated valve 38 is also positioned in the conduit 45 to regulate the flow of air therethrough by the vacuum of the intake manifold 32. A conduit 46 extends from the carburetor bowl of the carburetor 29 to the conduit 45 to vent the carburetor bowl to eliminate gasoline fumes therefrom. The air cleaner 28 includes an inner conduit 47 which communicates with the carburetor 29 and is secured thereto by a clamp 48. A sleeve 49 is mounted in the air cleaner 28 surrounding the conduit 47 and has a body of filtering material 50 contained therein. The sleeve 49 has a plurality of apertures 51 in the bottom thereof to permit a flow of air upwardly through the filtering material 50. A chamber 52 is formed on the conduit 47 outwardly thereof to contain a body of oil 53 to provide an oil bath air cleaning action. An outer shell 54 of generally cylindrical form extends downwardly over the chamber 52 and engages an O-ring seal 55 to seal the shell 54 to the chamber 52. A conical cover 56 is secured to the top of the shell 54 by means of a threaded shaft 57 and nut 58. The conduits 27, 44 are joined to the shell 54 to supply the desired air to the air cleaner 28. The venting air injector 31 includes an adaptor block 59 which is secured between the carburetor 29 and the intake manifold 32 by a pair of bolts 60. The adaptor block 59 has a central vertical bore 61 surrounded by a circular manifold 62. A plurality of downwardly and tangentially sloping jet apertures 63 extend from the manifold 62 into the bore 61. The conduit 30 extends tangentially into the manifold 62 on one side and the conduit 45 extends tangentially into the manifold 62 on the opposite side to supply air in a swirling motion through the manifold 62 which enters the bore 61 through the jet apertures 63 to provide a swirling motion of air therein as well as the venting products and the fuel mixture from the carburetor. Exhaust gases flow rearwardly from the combined integral heat exchanger and exhaust manifold 22 through a conventional exhaust system 64. In FIG. 7 a modified one-way air control valve useful with the present invention is illustrated in section. A conduit 65 extends from the intake manifold to a chamber 66 having a diaphragm 67 mounted therein. The chamber 66 has a threaded collar 68 forming part thereof and an actuating rod 69 extends therethrough from the diaphragm 67. A fitting 70 is threaded into the collar 68 and is secured therein by a jam nut 71. The fitting 70 has a valve plate 72 secured to one end thereof to cooperate with a valve 73 secured to the end of the rod 69 opposite the diaphragm 67. A fitting 74 is secured to the valve plate 72 by a plurality of bolts 75 and has an air filter 76 mounted therein. Air normally flows through the fitting 74 and through the valve plate 72 when the valve 73 is in open position. The air then flows into fittings 70 and outwardly through conduits 77, 78 to the point of use. In the use and operation of the invention air under pressure is supplied to a heat exchanger 22 which is heated by the exhaust manifold and the heated air is fed underpressure to the air cleaner 28 and to the venting air injector 31. With heated air supplied both to the air cleaner 28 and to the venting air injector 31 the air, fuel ratio is changed radically to decrease the fuel use while increasing the engine speed and power. The linkage 37 controls the flow of air to the venting air injector 31 conversant with the foot pedal position in controlling the speed of the motor vehicle. The first throttle valve 35 is actuated by the conventional accelerator foot pedal before the carburetor throttle valve moves off of idling position. First throttle valve 35 serves to control the power and speed during normal cruising speed and in restricted speed areas, then if additional power and speed are needed the foot pedal will open the carburetor throttle valve. The valve 35 is free to operate independently of the carburetor throttle valve. The engine 21 illustrated in FIGS. 1 through 6 is of a four or six cylinder variety but could be of any number of cylinders desired. In FIGS. 8 through 13 the anti-pollution structure with a fuel economizing fuel feed and exhaust system indicated generally at 80 is shown applied to a V8 engine indicated generally at 81. The V8 engine 81 is of conventional internal design and includes a block 82 having a water pump 83 mounted on the forward end thereof. The water pump shaft 84 is mounted in a bearing 85 in a housing 86. A fan 87 is mounted on the forward end of the shaft 84 and has a pulley 88 secured thereto. An air blower impeller 89 is secured to the pulley 88 so that rotation of the fan pulley 88 causes a flow of air underpressure in conduits 90, 91 which extends from the blower 92. The conduit 90 extends to a heat exchanger 93 and the conduit 91 extends to a heat exchanger 94. The heat exchangers 93, 94 are identical for opposite banks of the V8 engine 81. The heat exchanger 94 is an integral part of the exhaust manifold 95 which contains exhaust burners from my U.S. Pat. No. 3,630,031 patented Dec. 28, 1971 and entitled Anti-Pollution System for Internal Combustion Engines. The exhaust manifold 95 has a plurality of ports 96 formed therein so that air flowing into the heat exchanger 94 from the conduits 90, 91 can flow into the exhaust burners mentioned above. A portion of the air heated in the heat exchanger 94 flows outwardly through a conduit 97 to the air cleaner 98 of a carburetor 99. A conduit 100 extends from the heat exchanger 93 to the opposite side of the air cleaner 98. A conduit 101 extends from the conduit 97 to a venting air injector 102 with the air first passing through a filter 103. A conduit 104 extends from the conduit 100 through a filter 105 to the venting air injector 102. A conduit 106 extends from the valve cover 107 and are connected through a PCV valve P to the conduit 101 so as to vent oil and fuel fumes from the valve chambers enclosed by the valve covers 107. A conduit 108 extends from the crank case of the engine 81 to a PCV valve 109 to the conduit 101 so as to vent the crank case of fumes. A conduit 110 extends from the carburetor bowl of the carburetor 99 through a PCV valve 111 to eliminate gasoline fumes from the carburetor bowl. The venting air injector 102 while similar in function to the venting air injector 59 of the engine 21 is modified to provide for the throats of the carburetor 99 and includes tangential venting air injector apertures 112, 113 connected to the conduit 101 and identical apertures on the opposite side connected to the conduit 104. The air cleaner 98 includes an outer shell 114 of generally cylindrical form connected to the conduits 97, 100 and an inner cage 115 having a dry filter 116 contained therein. The cage 115 with filter 116 can be interchanged as needed. A cover 117 is secured to the air cleaner 98 by means of a threaded shaft 118 and a removeable nut 119. Exhaust gases from the exhaust manifold 95 flow outwardly through exhaust conduits 120 in a conventional manner. The use and operation of the invention illustrated in FIGS. 8 through 13 is identical to that of the invention illustrated in FIGS. 1 through 6. The specific valving system illustrated in FIGS. 1 through 6 has not been illustrated in FIGS. 8 through 13 but would be used therewith to provide adequate and complete control of the engine 81. Having thus described the preferred embodiments of the invention it should be understood that numerous structural modifications and adaptations may be resorted to without departing from the spirit of the invention.	In the anti-pollution structure with a fuel economizing fuel feed and exhaust system for an internal combustion engine of the present invention an air blower is positively driven from the fan pulley and provides a supply of air to an exhaust heated heat exchanger with a portion of the air flowing into a plurality of exhaust burners and a portion of the air being fed to the air cleaner of the carburetor. Another portion of the air is fed into an air injector between the carburetor and the intake manifold to provide an extra supply of air at a relatively high velocity. The invention is illustrated as applied to both a V-8 engine and a 4 cylinder engine.	5
BACKGROUND OF THE INVENTION This invention relates to electrical switches that are useful for switching electrical power and for switching electrical signals at very low energy levels. In many types of switching requirements the contacts must open and close with a positive snap action in which the snap motion is independent of the speed at which the switch actuator is moved by its operator. Further, these snap type switches must be constructed so that the moving contact will come to rest in the fully ON or fully OFF positions, and not at some intermediate position. Further, when the actuator is released by the operator selected contacts must remain in the ON or OFF position to which they were last moved by the operator. In the past, the above desired properties were provided primarily by what are known as precision snap switches. These switches often are expensive to manufacture. The snap action slide switch of this invention achieves the above described operating objectives and is relatively simple and inexpensive to manufacture. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described by referring to the accompanying drawings wherein: FIG. 1 is a side view showing various internal features of the switch of this invention; FIG. 2 is a view taken substantially at section 2--2 of FIG. 1 and shows in detail the contacts of the switch; FIG. 3 is a view taken substantially at section 3--3 of FIG. 1 and shows in detail the spring detent means on the contact carrier and their relationship with the detent means on the housing; and FIG. 4 is a perspective view, in section, showing the detent spring means of this invention. DESCRIPTION OF PREFERRED EMBODIMENT The switch is comprised of a box-like molded plastic housing 10 that has an open bottom 11. The top of the housing is closed except for an elongated aperture 14 that permits the handle 16 of an actuator member 20 to extend therethrough. Actuator member 20 is slidable back and forth between respective extreme positions wherein the opposite end surfaces of handle 16 are in contact with opposite ends of aperture 14. Mounting tabs 22 and 24 having respective mounting holes 26, 28 therein extend outwardly from opposite sides of the top of housing 10. As seen in FIGS. 1 and 2, the bottom portions of opposite interior side walls of housing 10 have integrally molded therein six pairs of facing parallel slots 32a, 32b-42a, 42b that are adapted to slidingly receive respective stationary contacts 32, 34, 36, 38, 40 and 42. The pairs of facing slots extend to the open bottom of housing 10 and terminate somewhere around the mid region on the side walls. The stationary contacts are identical and have terminals 32c-42c that extend through a rigid insulating terminal board 48. The top portions of the stationary contacts are broad and are shaped to form edge tabs, such as 32t, FIG. 2, that are slidably engaged in a pair of facing slots 32a, 32b so as to be firmly retained in housing 10. The slots terminate at their top ends at a thickened portion 50 of the housing, thus blocking further insertion of the contacts. The central portion of each contact, between tabs 32t for example, bows outwardly to be engagable by the sliding contact, as will be explained. As is well understood in the art, the portions of the stationary contacts between the bottom ends of the terminals and the broad top portions may be bent and shaped in any manner to achieve desired spacings between adjacent contacts, and between parallel rows of the terminals. Terminal mounting board 48 is provided on opposite side edges with protruding tabs that fit into complementarily shaped apertures at the bottoms of the side walls of housing 10, thereby to secure the terminal board to the housing. The plastic side walls are sufficiently flexible to permit easy assembly and disassembly of the terminal board and housing. Other suitable fastening means may be provided if desired. For example, the interiors of the flexible side walls of housing 10 may be provided with detents or barbs that releasably engage straight edges of the terminal board so as to hold the board in the housing. A molded plastic contact carrier 60 is positioned between the side walls of hollow rectangularly shaped housing 10 and is adapted to slide on the top surface of terminal mounting board 48. As seen in FIGS. 1 and 2, the lower portions of the opposite side walls of contact carrier 60 have respective pairs of facing slots 62, 64 and 66, 68 molded therein. Elongated, rectangularly shaped sliding contacts 74 and 76 have their ends fashioned to form tabs that are insertable into the slots 62, 64 and 66, 68. Helical springs 78 and 80 are received within the centrally positioned apertures 78a and 80a and spring bias the respective sliding contacts 74 and 76 outwardly into sliding contact with selected ones of the stationary contacts. As seen in FIGS. 1 and 3, two pairs of molded posts or fins 82, 84 and 86, 88 are located near opposite ends of contact carrier 60 and extend upwardly from the top surface of the contact carrier. The tops of posts 82, 84, 86 and 88 are in sliding contact with the bottom surface of actuator 20. Posts 82, 84, 86 and 88 thus properly position contact carrier 60 within housing 10 and prevent the contact carrier from becoming cocked during its sliding movement. A molded plastic spring detent member 100 also is placed on top of contact carrier 60. Spring detent member 100 desirably is molded as an integral unit and includes a closed loop or band of generally rectangular shape that forms a base detenting member 102. Two outwardly projecting detents 104 and 106 are located at the mid regions on the opposite long side legs of base detenting member 102. A shaped central web or strap 110 has a central apex 112 that extends between the two ends of base member 102 and serves as a spring member, as will be explained below. As seen in FIGS. 1 and 3, small rectangularly shaped keys 114 and 116 are integrally molded at the center on each end of the top surface of contact carrier 60. Respective rectangular notches 120, 122 in the bottom center at each end of base detenting member 102 fit over the keys 114 and 116 and aid in positioning spring detent member 100. Posts 82, 84, 86 and 88 also are shaped and positioned to receive the ends of center web 110 and the inside of the end legs of base detent 102 and maintain it in its desired fixed position on contact carrier 60. Each of the opposite interior side walls of housing 10 have vertically extending rounded detents 126, 128 molded therein and projecting inwardly toward the center of the housing. The detents 104 and 106 on the side legs of base detenting member 102 are positioned at a height to register with the respective detents 126 and 128 on housing 10. The thin plastic side legs of base detent member 102 are flexible and spring-like and will yield to permit their detents 104 and 106 to pass over detents 126 and 128 on the interior side walls of housing 10. The bottom surface of switch actuator 20, FIG. 1, has a V-shaped notch member 140 with two inclined cam surfaces 142 and 144 integrally molded thereon. V-shaped notch member 140 is wide enough to intercept a pair of the posts 82, 84 or 86, 88, as will be explained. The apex 112 of the center web or strap 119 of spring detent member 100 is adapted to fit in the base of the V-shaped notch between the inclined cam surfaces 142 and 144. Web 110 is of thin plastic material and is flexible and spring-like. As best seen in FIG. 4, web 110 has two curved portions 110a and 110b for storing energy therein when the apex 112 is pushed downwardly. Although not presently desired, web 110 may be molded independently of detent base member 102. In operation, assuming that the component parts are in the positions illustrated in FIG. 1, it is seen that the apex 112 of center web 110 of spring detent member 100 is centered in the V-shaped notch member 140. Further, as seen in FIG. 3, detents 104 and 106 on the side legs of the base detent member 102 are on the right side of housing detents 126 and 128. Actuator 20 is at its extreme right position. With these assumed positions, sliding contacts 74 and 76 establish electrical continuity between the center terminals and the respective terminals on the right end of the switch. To change the switching condition of the switch the operator pushes actuator 20 to the left. As the actuator first begins to move the apex 112 on the center web or strap 110 begins to move down the inclined cam surface 144, causing web 110 to begin to flex downwardly and store energy. During the initial movement of actuator 20, the contact carrier 60 will not move because of the frictional forces between the stationary and sliding contacts and the resistive forces produced as a result of detents 104 and 106 on spring detent member 100 interfering with projecting housing detents 126 and 128. As actuator 20 continues to move to the left web 110 will be deflected more as apex 112 slides further down cam surface 144. This will continue until the left edge 154 of the V-shaped notch member 140 contacts the right edges 156 of posts 82 and 84 on the top of contact carrier 60. Firm contact now having been made, contact carrier 60 will move to the left as actuator 20 continues to move to the left. Base detent member 102 now moves relative to housing 10 and the detents 104 and 106 now begin to move up the right sides of housing detents 126 and 128. The flexible side legs of base detent 102 begin to flex inwardly, thus storing energy. The apex 112 of flexible center web 110 still is somewhere on the inclined cam surface 144 of V-shaped notch member 140 as actuator 20 and contact carrier 60 first begin to move together. Thus, web 110 continues to store energy at this time. It is to be noted that the notches 120 and 122, FIGS. 3 and 4, on the undersides of the end legs of base detent means 102 are seated on the respective protruding keys 114 and 116 on contact carrier 60, thus preventing the end legs from flexing. This fixes the ends of web 110 and assures that the energy is stored in the flexed web 110 rather than the end legs. As detents 104 and 106 on base detent member 102 continue to move up the curved surface of housing detents 126 and 128 the side legs of the base member 102 flex more and store additional energy. At some point in the movement of contact carrier 60 the contact angle between detents 104, 106 and housing detents 126 and 128 reaches a predetermined low angle at which the resistive force therebetween decreases to a predetermined magnitude. At this point the energy stored in flexed web 110 is greater than the combined resistive forces between the contacts and between the detents 104, 106 and 126, 128. When this condition is reached the contact carrier 60 will accelerate and snap to the left at a greater speed than the moving actuator 20. Detents 104 and 106 pass over the center high points of housing detents (or cams) 126 and 128 (if they have not already arrived there) and move down the opposite sides thereof as stored energy in the side legs of base member 102 is released. Similarly, the apex 112 of center web 110 slides up the inclined cam surface 144 to the base, or high point, of V-shaped notch member 140 and releases its stored energy as it unflexes. In the manner described, contact carrier 60 snaps to its extreme left position at which its left end is in substantial contact with the left end of housing 10 and/or the left side of actuator handle 16 is in contact with the left edge of aperture 14. The snapping action of contact carrier 60 carries actuator 20 with it since there is but small frictional force between the actuator and housing 10. When actuator 10 and contact carrier 60 come to rest the apex 112 of web 110 is centered in the V-shaped notch member 140 in the relationship illustrated in FIG. 1. Further, detents 104 and 106 of base detent member 102 are now on the far left sides of housing detents 126 and 128. This positions contact carrier 60 so that sliding contacts 74 and 76 are bridging the center and left-most stationary contacts. Contact carrier 60 will remain in this position and it will require a substantial force to move it back to the right in view of the combined resistive forces provided by the stationary and sliding contacts, the detents 104, 106 and 126, 128 and web 110 in engagement with cam surfaces 142 and 144 of V-shaped notch member 140. Consequently, the switch is "tease proof" in that it will take more than a casual, small, force to move contact carrier 60 away from the extreme position it was last switched to. Although the switch described herein is a double pole, double throw switch, the principles of the invention are equally applicable to other switch forms. In its broader aspects, this invention is not limited to the specific embodiment illustrated and described. Various changes and modifications may be made without departing from the inventive principles herein disclosed.	A snap action slide switch concludes an improved spring detent means including resilient spring means on the contact carrier which stores energy and releases the energy at such position of the contact carrier to enhance rapid movement of the contact carrier to its different switching position.	7
FIELD OF THE INVENTION This invention relates to the field of bioelectric detection generally and more specifically to low-noise, interference-resistant amplifiers adapted for accepting the signals from such electrodes and delivering amplified output signals to equipment for analyzing such signals. BACKGROUND OF THE INVENTION Unlike conventional hearing testing techniques which require the cooperation and participation of the subject or patient, Auditory Brainstem Response (ABR) testing senses the patient's hearing response automatically through the direct measurement of bioelectrical activity at the subject's brainstem. The use of Auditory Brainstem Response recordings has now become routine in the evaluation of hearing. They are particularly useful where difficulty would be encountered in conventional testing or where additional information is required beyond that available from conventional testing. Examples include infants who are uncooperative or are too young to respond consistently, foreign-language speaking adults, and suspected 8th nerve tumor patients. The ABR instrument provides an objective measure of the operation of the auditory system by using computer averaging to detect the small electrical potentials (typically less than a microvolt) generated on the scalp and near the ear when a click or tone pip at the ear causes a sequence of more or less synchronized volleys of neural firings along the auditory pathway. Computer averaging has long been used for stimulus/response measurement in patients. The technique involves a) the repetitive stimulus of the patient through one or more of his nerve systems (i.e., eye, ear, touch, etc.), b) the detection of the body's response through remotely located electrodes contacting or penetrating the skin and c) the repetitive sampling or "averaging" of the detected signal in synchronism with the stimulus so as to remove the background noise that is typically many dB greater than each detected signal. Several years ago, the applicant and others saw three unsolved problems in ABR instrumentation: 1. The electromagnetic output of traditional supra aural input headphones such as the Telephonics TDH-39 introduced an artifact into the output recording that was often impossible to separate from a real response. 2. Patient preparation included vigorous scrubbing (often resulting in lacerations) of the skin. The ABR pickup typically employed EEG electrode cups filled with silver-chloride paste, taped down over the scrubbed skin area. Several minutes were often required to prepare and apply the electrodes in order to keep the contact resistance below 5000 ohms, as was typically required in these tests. 3. Even with low-impedance electrode preparations, electrical interference from radio stations, fluorescent lights, diathermy machines and the like sometimes made it completely impossible to obtain useful ABR recordings. The applicant has previously described insert earphones which successfully solved the first problem, specifically in U.S. Pat. No. 4,677,679 dated July 5, 1984 and U.S. Pat. No. 4,766,753 dated Oct. 4, 1985, and a low-cost earcanal electrode that has simplified the electrode preparation in many cases due to the increased signal levels resulting from electrical pickup closer to the cochlea as described in U.S. Pat. No. 4,781,196 dated Nov. 1, 1988. These patents are incorporated herein by reference and form a part of the present disclosure. A solution to the interference problem was initially approached by attempting to locate a high-input-impedance amplifier close to the electrodes, in the belief that a lower output impedance driving the cables connecting the electrodes to the ABR equipment would alleviate the problem. After continuing failures with this approach, we built an electrically-quiet "BATMAN" (Brainstem Amplifier Test MANikin) with salty jello for brains. Tests with this manikin convinced us that our high-input-impedance electrode amplifier only indirectly tackled the real nemesis of clean bioelectric recordings: The human body acts as an efficient antenna for pickup of extraneous electromagnetic interference signals (EMI), some of which can amount to tens of volts in magnitude. Measures taken in good ABR equipment include the use of differential input amplifiers to obtain extraordinarily high common-mode-rejection ratios and large common-mode-input voltage ranges at high frequencies. These have been brute force (and in some environments regularly unsuccessful) attempts to avoid the contamination of the averaged signal from EMI pickup. The use of light-coupled isolation amplifiers to solve this and similar problems is well known, and light-coupled amplifier-transmitter-receiver-demodulator systems are commonly available. But their power consumption and cost has hitherto prevented their common use in ABR and similar equipment. SUMMARY OF THE INVENTION The present invention has as its principal object the provision of an electrode amplifier that is more resistant to interference from electromagnetic noise sources. It is a more specific object to provide an electrode amplifier that is resistant to interference from electromagnetic noise sources while being economical to manufacture and package. It is a further object to provide an electrode amplifier that operates efficiently from a low voltage power source such as a single electrochemical cell. It is still a further object to provide a local shielding configuration for the electrode amplifier that additionally minimizes the interference from electromagnetic noise sources. It is also an object of the present invention to provide an electrode amplifier that is effectively transparent to existing bioelectric signal analysis equipment, so that the interference problem may be solved without requiring reprogramming or other equipment modifications. Finally, it is a more general object of the invention to provide an improved and more economical light-coupled transmission system using pulse duration modulation. These and other objects and advantages are provided through a system for detecting and transmitting body electrical signals in the presence of ambient electrical interference that uses a transmitter circuit including an amplifier coupled to and in close proximity to two or more body electrodes, a light pulse generator that receives its input from that amplifier and provides a pulse-duration-modulated series of light pulses, and a remote receiver including a transducer which demodulates the transmitted light pulses into electrical pulses of corresponding duration and frequency and a demodulator which accepts electrical pulses and produces an amplified replica of the original signal developed between the body electrodes, thereby effectively providing complete electrical isolation of the electrode amplifier from the remaining bioelectrical signal analysis equipment. More specifically, these objects are accomplished in the present invention through the use of a version of the low-voltage, low-power Class D integrated circuit amplifier originally developed by the applicant for hearing aid applications (U.S. Pat. No. 4,592,087 dated May 27, 1986 and U.S. Pat. No. 4,689,819 dated Aug. 25, 1987, incorporated herein by reference to form a part of the present disclosure), in conjunction with a new voltage-doubler circuit and the unusual combination of a high-light-output fiber optic transmitter with a low-noise, low-battery-drain fiber optic receiver, and with the switching frequency of the Class D amplifier chosen so high that a four-stage passive R-C filter provides adequate filtering of the switching frequency in order to prevent unwanted interactions between it and the analog-to-digital converter in the input of the bioelectric signal equipment. A valuable additional feature of the invention is a complete electrostatic shield around the amplifier-transmitter as well as the electrode leads, so that the small amount of residual capacitive coupling to the amplifier circuit itself is effectively shunted to the same average (body) potential as that of the electrodes. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of the transmitter and receiver system of the present invention connected between bioelectric-pickup electrodes and conventional equipment that has been designed for bioelectrical signal analysis. FIG. 2 is a block diagram of an embodiment of the present invention that uses a fiber optic light pipe to carry the signal. FIG. 3 is a more detailed block diagram of a portion of the transmitter shown in FIG. 1. FIG. 4 is a more detailed schematic diagram of a portion of the transmitter shown in FIGS. 1 and 3. FIG. 5 is a schematic diagram of the receiver shown in FIG. 1, showing the regulator, fiber optic receiver, low pass filter, and gain selection circuit. FIG. 6 is a sketch of a "BATMAN" manikin, showing the location of three of the electrodes used in the development experiments. FIG. 7 is a diagram, partially in schematic form, illustrating the common-mode signal path for interfering electrostatic pickup found in conventional ABR equipment. FIG. 8A is a diagram, partially in schematic form, illustrating the radically reduced common-mode signal developed at the input to the system of the present invention. FIG. 8B is further circuit diagram, in simplified form, illustrating the nature of the residual common-mode signal developed at the input to the present invention. FIG. 9 is a sketch of a patient under test with a doubly-shielded isolation amplifier configuration. DESCRIPTION OF THE PREFERRED EMBODIMENT Turning now to the drawings, FIG. 1 illustrates the operation of the complete inventive electrode isolation amplifier system connected to a conventional bioelectric signal analyzer. A transmitter 10 contains an electronic amplifier 11 powered by a power source 12 and having a first input 13 adapted for coupling to a first scalp-mounted electrode 14 and a second input 15 adapted for coupling to a second scalp-mounted electrode 16, and a single output 17 whose voltage amplitude is a multiple of the difference in voltage between the signals at the two electrodes 14 and 16. Electrostatic shield 19 surrounds inputs 13 and 15 and encloses the amplifier 11, power source 12 and a light pulse generator 30, and is connected to an input terminal 18 which is, in turn, connected to a "ground" electrode 20 mounted on the scalp at a distance from the two electrodes 14 and 16. The light pulse generator 30 receives at its input 31 the output of the electronic amplifier 11 and provides at its output 32 a pulsatile light whose pulse period is relatively fixed and whose pulse duration is proportional to the voltage amplitude of the output signal generated by the electronic amplifier. Both the amplifier 11 and the light pulse generator 30 are powered by the power source 12 having a positive terminal connected to a supply buss 33 and a negative terminal connected to a common buss 34. Also shown in FIG. 1 is a receiver 60 which contains a light pulse transducer 70 with an input 71 configured to accept the transmitted light pulses from the transmitter 10 and convert them into electrical pulses at an output 72. The receiver 60 also contains a low-pass filter 80 which accepts the electrical pulses from the transducer 70 and effectively demodulates them into an amplified and isolated replica of the original voltage difference between the first and second scalp electrodes 14 and 16, which amplified replica is delivered via an active output 82 and reference output 83 to an input terminal box 90 of a bioelectric signal analysis system 100. The bioelectric signal analysis system 100 contains a differential amplifier 95 whose non-inverting input 97 is shown connected to an input terminal 92 and whose inverting input 98 is shown connected to a reference terminal 93. A shield 61 surrounds the receiver 60 and is connected to the ground terminal 94 of the input amplifier 95, whose output 96 provides a signal to an analog-to-digital converter 101. A computer averager circuit 102 accepts the output of an A-D converter 101 and drives a suitable display 103 and/or printout. The average circuit 102 is well-known in the art and provides an output which is the averaged sum of repetitively received signals such that a principal desired pulse is amplified while surrounding noise is effectively cancelled. It is interconnected with and operates in conjunction with, and typically in synchronism with, a stimulus generator (not shown) which provides the aural input to the ear through speakers, headphones or insert earphones as described above. In FIG. 1 light transmission from the output 32 to the receiver input 71 is through open space. FIG. 2 illustrates an alternative and preferred embodiment, in which a light pipe 50 connects transmitter 10 and receiver 60. FIG. 3 shows a more detailed block diagram of light pulse generator 30, with an input 31 coupled through a capacitor 37 to a class D amplifier 40 whose output 42 is a square wave with duty cycle proportional to the voltage appearing between the input terminal 31 and a common terminal 34 as described in the aforementioned U.S. Pat. Nos. 4,592,087 and 4,689,819 incorporated herein by reference. The output 42 of class D amplifier 40 drives a voltage doubler 50 whose output 52 provides the greater-than-1.5 volt square wave drive required by the light-emitting diode (shown below in FIG. 4) in the preferred embodiment of the light source 60. FIG. 4 shows a schematic diagram of a preferred embodiment of parts of generator 30, where a pair of output transistors P27 and N27, as shown in FIG. 4 of and described in U.S. Pat. No. 4,689,819, supply current through a current-limiting resistor R50 to drive PNP transistor Q50 into conduction during the low-voltage output portion of the duty cycle of the Class D amplifier, thereupon charging a storage capacitor C50 to approximately 1.5 volts. On the high-voltage-output portion of the duty cycle of Class D amplifier, a voltage roughly double the supply voltage between buss 33 and common bus 34 is supplied to light source 60. The light source 60 is preferably a Thomas and Betts Model 92915-T-DD fiber optic transmitter. FIG. 5 shows a simplified schematic of the receiver 60, in which a supply 62, which may be a 9 Volt transistor radio battery, drives a regulator 72 providing 5 volts DC to the fiber optic receiver 73. Alternately, the supply 62 may be obtained from the ABR equipment itself. The fiber optic receiver 73 is preferably an hp Model 2521, whose input 71 accepts the receiver end of the fiber optic cable 50 and whose output 72 supplies an input to the low pass filter 80. By choosing the operating frequency of the class D amplifier 40 of FIG. 3 to be in the neighborhood of 300 kHz, four stages of passive R-C filtering can provide 90 dB of attenuation at the switching frequency (without significant attenuation to the desired signal in the 100 to 5000 Hz passband used for most ABR measurements). This avoids any interference with the operation of subsequent signal processing means (in the aforementioned bioelectric signal system) that might otherwise occur due to the pulsatile nature of the transmitted and received signal. A gain selection network 68 consisting of fixed resistors 68a, 68b, 68c and 68d and a selection switch 68e is provided, permitting manually selectable overall system gains between 1× and 100×. A system gain of 1× is particularly convenient so that the operation of the inventive system appears transparent to existing sensory-electrode signal-analysis equipment except for the desired increase in resistance to disturbance from electromagnetic interference. In some situations, however, additional noise rejection can be obtained with a system gain of 2× or more. FIG. 6 shows a sketch of "BATMAN," a test "manikin" with electrodes 14A, 16A, and 20A formed from conventional electrode plug jacks but with a small wad of copper "Chore Girl" scrub brush on the inside of the manikin's head imbedded in a salty jello solution used to simulate an electrically quiet but normally conductive brain. FIG. 7 is an equivalent circuit that illustrates the most important interference problem normally encountered, with somewhat arbitrary values of 5000 ohms shown for each electrode impedance. As is well understood, the actual impedance of a surface electrode on the skin varies with both preparation and test frequency, and only rarely do even two of the three electrodes exhibit the same impedance. The values shown are adequate for our purposes however, since only the existence of an appreciable impedance between each electrode and the "body" is required for the present explanation. Assuming an electrostatically-coupled source of noise having open circuit potential of NOISE, and taking a commonly measured capacitance from a body to "space" of about 800 pF and the assumed value of 5000 Ohms for the impedance of each electrode, it can be readily calculated that above about 40 kHz the common mode signal impressed on the inputs 91 and 92 of the conventional differential amplifier 95 is unattenuated, but equal to the open circuit value of eNOISE. When eNOISE exceeds the typical 10 volts common-mode input range of the typical operational amplifier, overload occurs and the operation of the signal averager is severely compromised. Even in the laboratory, several miles from the nearest radio stations (at 670 kHz and 720 kHz), open circuit voltages of several volts at 670 and 720 kHz were measured, indicating the severity of the problem for someone closer to such interference sources. FIG. 8A shows the dramatically improved situation in which the input amplifier is mounted on or near the head in a small electrostatically shielded box, as in the present invention. Taking the surface area of a typical human as roughly 2000 square inches, and the prototype box surface area of about 10 square inches, the total coupling of roughly 800 pF is now divided into 796 pF to the head and body and 4 pF to the electrostatic shield of the transmitter box 10. If there is no capacitive coupling from the body to earth ground, there is no common mode signal developed at inputs 13 and 15 of transmitter 10, since eBODY and e18 are the same voltage. In practice, a few hundred pF of capacitance to the couch or chair in which the patient is relaxing may be expected. FIG. 8B illustrates a further simplified circuit for the purpose of calculating the residual common mode signal when 200 pF of capacitance exists between the patient and earth ground. Even here, the common mode signal is attenuated 60 dB (0.001x) at 40 kHz and 40 dB 0.01x) at 400 kHz compared to that present at the input of differential amplifiers used in conventional ABR and other bioelectric signal equipment. FIG. 9 shows the use of an additional electrostatic shield 150, connected to a fourth electrode 151 in such a way that the primary electrostatic coupling from the source of noise voltage eNOISE is intercepted and shunted through the assumed 5 kOhm electrode impedance of electrode 151 to the patient's body. Shield 150 may take the form of a large bowl-shaped conductive shield around the head similar in shape and appearance to a hair dryer found in beauty shops. Alternately, shield 150 may be made in the form of a scarf or "babushka" woven at least partially of conductive thread such as carbonized nylon or interwoven with fine metallic strands, connected in either case to a new body electrode which may conveniently be in the form of a wrist strap. When made in the form of a scarf, shield 150 is tied around the head so that it covers the electrodes 14, 16, and 20 and the transmitter 10. (With appropriate choice of colors, these electrostatic shields might even become important fashion statements among chronic ABR patients, but no such claim is made here.) It is readily seen that with the shield 150 in place, the majority of the capacitively induced current that would otherwise develop a common mode voltage at terminal 18 is shunted to the body through electrode 151, providing a further 20 to 40 dB improvement in interference rejection. The dramatic reduction in common mode voltage provided by the shielding configuration of FIGS. 8a and 8b permits a simple "single-ended" input design for the input amplifier 11 of FIG. 1, provided that a balance in circuit-to-shield capacitance is maintained for inputs 13 and 15. In particular, a simple "single-ended input" amplifier effectively becomes, in this light-coupled, electrostatically-shielded configuration, a differential amplifier with extraordinarily high common mode rejection ratio: A measured improvement of some 26 dB in interference rejection is obtained over the best-quality conventional bioelectric-pickup differential amplifiers. Indeed, clean ABR recordings can be achieved with the inventive amplifier even while the patient under test is grasping an active desk-type fluorescent light fixture and bulb: a source of interference that typically overloads the high-quality conventional ABR equipment by a factor of 10 to 20 times, preventing any interpretable readout. Since interference pickup is proportional to the size of the surface area of the transmitter assembly and its optional electrostatic shield, operation is enhanced in the present embodiment by the availability of the aforementioned self-contained class D amplifier integrated circuit chip measuring approximately 2 mm by 1 mm by 0.3 mm thick (the light emitting diode element in the transmitter can be of similar dimensions), which permits an unusually small size for such a transmitter package. Similarly, the high efficiency of that class D amplifier and its proper operation with supply voltages as low as 1.1 volts means that a miniature hearing-aid size single-cell "battery" can provide adequate power while maintaining a small size for the overall package. The complete transmitter can be operated from a single-cell "675" size hearing aid battery with a current drain of only 5-10 mA, permitting 40 hours or more of operation before battery replacement is required, at a cost of only a few cents per hour of operation: a trivial cost when compared to the typically $100 to $200 per hour that is charged for ABR measurements. One successful measurement that would otherwise have been lost to interference would pay for batteries for several thousand complete ABR measurements.	A system for detecting and transmitting body electrical signals in the presence of ambient electrical interference that uses a transmiter circuit including an amplifier coupled to and in close proximity to two or more body electrodes, a light pulse generator that receives its input from that amplifier and provides a pulse-duration-modulated series of light pulses, and a remote receiver including a transducer which demodulates the transmitted light pulses into electrical pulses of corresponding duration and frequency and a demodulator which accepts those electrical pulses and produces an amplified replica of the original signal developed between the body electrodes, thereby effectively providing complete electrical isolation of the electrode amplifier from the remaining bioelectrical signal analysis equipment. A valuable additional feature of the invention is a complete electrostatic shield around the amplifier-transmitter as well as the electode leads, so that the small amount of residual capacitive coupling to the amplifier circuit itself is effectively shunted to the same average (body) potential as that of the electrodes.	0
This application is a continuation-in-part of our copending application, Ser. No. 267,048, filed June 28, 1972, now U.S. Pat. No. 3,862,981. BACKGROUND OF THE INVENTION The present invention relates to new lubricating oil additives which impart to lubricating oils good detergent, dispersing and anti-rust properties. This invention relates also to lubricating oils and to fuels and carburants containing said additives. There are known to the prior art, additives for lubricating oils which consist of derivatives of carboxylic acids substituted with slightly unsaturated hydrocarbons. This class of additives, which has been known for some years, was an important development to the lubricating oil art. They consist mainly of reaction products of carboxylic acid acylating agents, substituted with a fairly saturated hydrocarbon radical containing an aliphatic chain of at least 30 carbon atoms, preferably 50 carbon atoms, with amines or alcohols. Lubricating oil additives in the nature of acylated amines produced from the reaction of substituted carboxylic acid acylation agents with amines, such as disclosed in U.S. Pat. No. 3,172,892, granted Mar. 9, 1965, are known for their desirable dispersing properties, especially with regard to sludge. A "sludge" is the product formed in a motor crank case when the temperature of the lubricating agent in the crank case is alternately low and high or maintained at a low temperature in a continuous way. This last condition frequently occurs in urban traffic in what is frequently referred to as "door to door" travel at low speeds. Low operating temperatures favor water formation and accumulation within the lubricating agent. The combination of condensed water, of curburant and lubricating agent, decomposition products, and of oil forms the sludge. This sludge, which is not readily dispersed, may be damaging to the operation of a motor. Lubricating agent additives in the form of esters resulting from the reaction of the same foregoing acylation agents with alcohols or phenols are efficient anti-rust agents and reasonably good detergents. Products of this nature are disclosed in U.S. Pat. No. 3,381,022, granted Apr. 30, 1968. The dispersing action of these additives is, however, limited by their relatively low thermal stability, by their lack of resistance to hydrolysis, and by their acidity. It is an object of the present invention to provide a lubricating oil additive which does not have the shortcomings of the prior art additives. It is also an object of the present invention to provide lubricating oils containing the new additives and which oils have improved dispersing, detergent and anti-rust properties. Another object of the present invention is the provision of a lubricating oil additive having improved properties over those of the prior art alkyl substituted carboxylic acid esters described, for example, in U.S. Pat. No. 3,381,022, and also with regard to the amide derivatives described in the U.S. Pat. No. 3,172,892. Other objects of the invention will be apparent to those skilled in the art from the present description. GENERAL DESCRIPTION OF THE INVENTION The lubricating oil additives of the present invention comprise reaction products of an alcohol or hydroxyaromatic compound with a hydrocarbon chain substituted carboxylic acid, anhydride, chloride or ester, which hydrocarbon chain substituent is substantially saturated and contains at least 30, and preferably at least 50, carbon atoms, said resulting product being then neutralized with an ashless basic compound to provide in the final reaction product at least about 0.9% by weight of nitrogen. After an extensive research investigation it has been found that these additives impart improved detergency, dispersing and anti-rust properties to lubricating oils, fuel oils and carburants. These novel additives and products of the invention are produced in the form of a complex mixture, rather than a precise chemical compound, of which it is difficult to determine the exact chemical composition and the relative proportions present of the various constituents. It is for this reason that the products must be described in terms of the process of manufacturing them. The presence of the ester grouping resulting from the reaction of the alcohol or hydroxyaromatic compound and the substituted carboxylic acid, anhydride, chloride or ester has been confirmed by infra-red analysis. The esterification reaction between the substituted carboxylic acid, anhydride, etc., acylating agent and the alcohol or hydroxyaromatic compound results in an equilibrium difficult to displace; the resulting product contains in solution a variable proportion of the unreacted acylating agent and, as a dispersion in said solution, unreacted alcohol or hydroxyaromatic compound. It is essential, in order to obtain good dispersing properties when employing the product as a lubricating oil additive, to neutralize completely the complex reaction mixture with an ashless basic nitrogen compound. The content of this reaction mixture in residual acid compounds, acid and/or anhydride functional groups, is evaluated by methods conventional for each type of acylating agent. For example, a simple potentiometric titration may be concerned in the case when acylation agent is a monocarboxylic acid or a determination by infrared spectroscopy in the case where the acylation agent is a substituted cyclic anhydride, or any other suitable method taken separately or in combination may be employed. In fact, the content of residual acid components must have a determined value if it is desired to obtain, after neutralization by an ashless basic compound, a product possessing good dispersing properties with regard to sludge. It has appeared more practical to express the content of residual acid components in terms of a minimal nitrogen content in the final product. This minimal nitrogen content, which determines the quantity of ashless basic nitrogen compound necessary for neutralizing the residual acid components (acid and/or anhydride functional groups) expresses the basicity degree to be introduced in the medium for obtaining a product having good dispersing power. This minimal content in nitrogen is about 0.9% by weight. It is comprised in the final complex mixture between about 0.9 and 2.5%. This amount is important if satisfactory results are to be obtained. Consideration has been given to neutralizing the complex mixture by means of a metal base compound such as barium, magnesium or calcium oxides. However, the resulting final products, if they are good detergents possessing anti-rust properties, are poor dispersing agents. However, if the complex mixtures are neutralized, in accordance with the present invention, with an ashless basic nitrogen compound, such as an aminated compound, and among this class of compounds more especially polyamines, the resulting complex products are good dispersing agents, the anti-rust efficiency of which depends upon ester quantity present in the final compound. It has been tried to reconstitute artificially the invention complex product by mixing a neutral ester and succinimide, but it has been found that the dispersing power was clearly lower and unsatisfactory. It is, therefore, obvious that the products of the invention are not simple mixtures of esters and succinimides. Carboxylic acids substituted with a fairly saturated hydrocarbon chain containing at least 30 carbon atoms, and preferably at least about 50 carbon atoms, or their substituted derivatives such as anhydrides, acid chlorides, esters, are the preferred acylation agents of the present invention. They are prepared in reacting an ethylenically unsaturated carboxylic acid, or an anhydride, an halide, or an alkyl ester of the acid, with an unsaturated polyolefin or an halogenated polyolefin of high molecular weight, having at least about 30 carbon atoms, and preferably about 50 carbons, on the chain. Reaction consists only of heating the two bodies in reaction at a temperature comprised between 150° and 250°C. Those products, of high molecular weight, may contain polar substituted groups or lateral hydrocarbon substitution groups. As the carboxylic acid moiety, ethylenically unsaturated carboxylic compounds, may be employed including monoacids, such as acrylic acid, methacrylic acid; diacids, such as maleic, fumaric, itaconic acids, their anhydrides or their chlorinated derivatives, ethylenic acids of C 5 , C 6 , etc. Succinic anhydride and succinic acid both substituted by a fairly saturated hydrocarbon group containing at least 50 carbon atoms, are the preferred acylation agents. They are easily obtained by reaction of maleic acid or anhydride with a polyolefin, such as polyethylene, polypropylene polybutylene, polyisobutylene, polypentene, etc., or a chlorinated polyolefin, such as chlorinated polypropylene. Those products have a molecular weight sufficient for reaching a condensation product of about 50 molecular units. Practically speaking, the molecular weight is at least about 700. Suitable esterification agents for the substituted carboxylic acids defined hereinabove, may vary greatly. These may include aliphatic monoalcohols, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, hexyl, heptyl, octyl, isooctyl, nonyl, decyl alcohols, fatty alcohols, etc.; aromatic or cycloaliphatic monoalcohols, such as benzyl alcohol, cyclohexanol, etc.; polyalcohols, such as ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, glycerol, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, mannitol, etc.; and partially esterified esters of those polyols. It is also possible to use unsaturated alcohols, such as allyl alcohol, unsaturated polyols, substituted alcohols such as the amino-alcohols. Hydroxyaromatic compounds, such as the phenolic compounds, may be employed to esterify the substituted carboxylic acid, anhydride, etc. These include phenol, the cresols, naphthols, alkylphenols, such as amylphenol, nonylphenol, dodecylphenol, halogenated phenols, diphenols, such as p,p'-dihydroxydiphenol, resorcinol, pyrocatechol, hydroquinone, diphenylolmethane, diphenylolpropane, etc. Esterification, the time of which is comprised between 1 and 10 hours at a temperature of between about 50° and 300°C., preferably between about 100° to 200°C., may take place at atmospheric pressure, under pressure, at reduced pressure, or under nitrogen atmosphere, in the presence or in the absence of carrier solvent such as xylene, toluene, etc., this solvent facilitating both temperature control and water removal from the reaction mixture, by azeotrope formation. The esterification reaction may take place in the presence of a classical esterification catalyst, such as pyridine or its hydrochloride, sulfuric acid, para-toluene sulfonic acid and resins having a strongly or moderately acid character. It may also be achieved in the absence of any catalyst. The relative proportions of the two constituents, alcohol or phenolic compound and aliphatic substituted carboxylic acid or anhydride, may vary within large limits. But in any event, since esterification is usually not complete, the remaining substituted acid or anhydride must afterwards be neutralized with an ashless basic nitrogen compound. Such neutralization is an important feature of the invention, as stated hereinabove, as it is necessary to obtain good dispersing properties. The unreacted alcohol or phenolic compound, finely dispersed in the product resulting from the esterification reaction, may be removed if it is in a substantial quantity. Otherwise it may remain in the product in a divided form without involving any disadvantage or incompatibility. Suitable ashless basic compounds include ammonia, aliphatic, aromatic, or heterocyclic mono-amines, such as ethylamine, butylamine, aniline, pyridine, quinoline, etc., amines having polar groups, such as hydroxypropylene, nitroaniline, etc., alkylsubstituted amines, hydroxylated amines. Preferably polyamines shall be employed such as alkylidene diamines, triamines, tetramines, pentamines, hexamines; ethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine, polypropylene polyamide - polybutylene polyamines. Ureas, thioureas, hydrazines, cyanamides, etc., may be employed. This neutralization is accomplished by heating the reaction mixture and ashless basic compound at a temperature of about 100° to 250°C. for a period of 1 to 6 hours, preferably 1 to 3 hours, under light vacuum, or by any other method known in the art of facilitating removal of water formed by a reaction. The molar ratio when a polyamine is employed and the residual acid compounds present in esterification mixture is desirably between about 0.25 and 2, preferably between 0.4 and 1.5. The complex mixture resulting from neutralization is difficult to analyze. Therefore, the industrial new products obtained after this final stage, having excellent dispersing power, will be defined by their general process of manufacture. DETAILED DESCRIPTION OF THE INVENTION In order to disclose more clearly the nature of the present invention, the following examples illustrating the invention are given. It should be understood, however, that this is done solely by way of example and is intended neither to delineate the scope of the invention nor limit the ambit of the appended claims. In the examples which follow, and through the specification, the quantities of material are expressed in terms of parts by weight, unless otherwise specified. The acylation agent used in the Examples 1 through 12 was the reaction product of 350 grams of maleic anhydride with 2500 grams of a polyisobutene having a molecular weight equal to about 1000, heated at a temperature of between 190° and 240°C. for 10 hours. The resulting product is a polyisobutylene substituted-succinic anhydride. EXAMPLE 1 a. 1258 grams of polyisobutylene substituted succinic anhydride, prepared as hereinabove, having a Pibsa index = 62.5 [Pibsa index (for polyisobutenylsuccinic anhydride) is the number of potash milligrams necessary to neutralize 1 gram of the product] were reacted with 11.9 grams of pentaerythritol for 3 hours, 50 minutes at a temperature of 140°-150°C., then for 2 hours at 180°-190°C. b. 200 grams of the product prepared hereinabove in part a) were reacted with 6.8 grams of tetraethylenepentamine at a temperature of 155°C. for 2 hours under a partial vacuum (about 400 mm. Hg. pressure). The vacuum treatment was continued providing evaporation at a pressure of 20 mm. Hg. for 30 minutes. This vacuum treatment facilitated removal of water formed during the reaction. The resulting product had a nitrogen weight percentage of 1.21%. EXAMPLE 2 a. 898 grams of polyisobutylene substituted-succinic anhydride, produced as hereinabove, having a Pibsa index = 62.5, were reacted with 12 grams of glycerol for 3 hours at a temperature of 150°C., followed by 3 hours at 190°C. b. 300 grams of the product of part a) hereinabove were reacted with 9.6 grams of triethylenetetramine under the same reaction conditions as in Example 1b). Nitrogen weight percentage in the final product was 1.17%. EXAMPLE 3 a. 1258 grams of polyisobutylene substituted-succinic anhydride, produced as hereinabove, having a Pibsa index = 62.5, were reacted with 19 grams of pentaerythritol for 4 hours at a temperature of 150°C., then for 2 hours at 190°C. b. 150 grams of the product prepared in part a) were reacted with 4.9 grams of tetraethylenepentamine under the same reaction conditions as in Examples 1b). Nitrogen weight percentage of the final product was 1.11%. EXAMPLE 4 a. 1796 grams of polyisobutylene substituted-succinic anhydride, produced as hereinabove, having a Pibsa index = 62.5, were reacted with 94 grams of phenol in the presence of 280 grams of xylene for 1.5 hours at a temperature of 160°C. Then 9 grams of p-toluene sulfonic acid were added and reaction continued for 2 hours at 160°C. Water formed during the reaction was removed by means of a Dean-Starck apparatus. Afterwards distillation was conducted under reduced pressure (20 mm. Hg.) for 1 hour at 160°C. b. 200 grams of the product prepared in part a) were reacted with 6 grams of tetraethylene pentamine under the reaction conditions of Example 1b). Nitrogen weight percentage of the final product was 1.08%. EXAMPLE 5 a. 898 grams of polyisobutylene substituted-succinic anhydride, produced as hereinabove, having a Pibsa index = 56, were reacted with 94 grams of phenol in the presence of 150 grams of xylene for 2 hours at a temperature of 160°C. Then 5 grams of p-toluene sulfonic acid were added and reaction continued for another hour at 160°C. Water formed during the reaction was removed by means of a Dean-Starck apparatus. Reaction was concluded under reduced pressure (20 mm. Hg.) for 1.5 hours at 160°C. b. 200 grams of the product prepared in part a) were reacted with 6.8 grams of triethylenetetramine under the same reaction conditions as in Example 1b). Nitrogen weight percentage of the final product was 1.25%. EXAMPLE 6 200 grams of the product prepared in Example 4, part a), were reacted with 8.81 grams of tetraethylenepentamine under the same reaction conditions as in Example 1b). Nitrogen weight percentage in the final product was 1.55%. EXAMPLE 7 2 kilograms of polyisobutylene substituted-succinic anhydride, prepared as hereinabove [Pibsa index = 53] were reacted with 107 grams of diphenylol propane in the presence of 21 grams of p-toluenesulfonic acid catalyst for 4 hours at a temperature of 160°C. The product was then vaporized under vacuum at 160°C. for 1 hour, and neutralized with 82 grams of tetraethylenepentamine at 155°C. for 2 hours, under a partial vacuum (400 mm. Hg. pressure, approximately). This treatment was followed with a vaporization at 20 mm. Hg. pressure for 30 minutes. Nitrogen content in the final product was 1.29%. EXAMPLE 8 62.5 grams of diphenylolpropane were heated at 170°C. 484 grams of polyisobutylene substituted-succinic acid prepared as hereinabove (Pibsa Index = 63.5) were introduced over 15 minutes at 170°C. under 400 mm. Hg. pressure. The reaction proceeded for 4 hours (170°C. under partial vacuum). 543 grams of the resulting product were treated afterwards with 21.5 grams of tetraethylenepentamine under the same conditions as in Example 7. Nitrogen content in final product was 1.40%. EXAMPLE 9 64 grams of diphenylolpropane were heated in the presence of 472 grams of xylene at 110°-115°C. Then 1257 grams of polyisobutylene substituted-succinic anhydride prepared as hereinabove, (Pibsa Index = 62.5), were introduced over a period of 25 minutes. After 1 hour of reaction at 110°-115°C., 13.2 grams of pyridine were added. A second addition of an equal amount of pyridine was made after 2 hours of reaction. After 3.5 hours of reaction, the product is vapourized at 140°C. under 20 mm. Hg. pressure for 30 minutes. EXAMPLE 10 200 grams of the product of Example 9 were neutralized with 5.6 grams of tetraethylenepentamine under the same conditions as in Example 7. Nitrogen content of the final product was 1%. EXAMPLE 11 200 grams of the product of Example 9 were neutralized with 7.7 grams of triethylenetetramine under the same conditions as in Example 7. Nitrogen content of the final product was 1.42% EXAMPLE 12 6640 grams of polyisobutylene substituted-succinic anhydride (Pibsa Index = 76.3) were reacted with 465 grams of diphenylolpropane in the presence of 53 grams of para-toluene sulfonic acid for 2.5 hours at 162.5°C. Then the product was vapourized under vacuum for 1.5 hours. 667 grams of the resulting product were neutralized with 23.1 grams of tetraethylenepentamine under the same conditions as in Example 7. Nitrogen content of the final product obtained in this way was 1.23%. EXAMPLE 13 The acylating agent employed in this example was the reaction product of maleic anhydride with a polyisobutene having a molecular weight equal to about 455, heated at a temperature between 190° and 240°C. for 10 hours. 200 grams of the resulting polyisobutylene substituted-succinic anhydride (Pibsa Index = 81) were reacted with 16.46 grams of diphenylolpropane and 2.1 grams of p-toluene-sulfonic acid over 4 hours at 170°C. and for 30 minutes under vacuum at 170°C. 201 grams of the resulting product were reacted with 9 grams of tetraethylenepentamine at 155°C. for 2 hours under partial vacuum (about 400 mm. Hg. pressure). Treatment was completed under vacuum of 20 mm. Hg. pressure for 30 minutes. Nitrogen content of the final product was 1.44%. The acylation agent used in Examples 14 and 15 below, was the reaction product of acrylic acid with a chlorinated polyisobutene, heated at temperature of 180°-190°C. during 10 hours. The obtained chlorinated polyisobutenylpropionic acid had an acid index of 31 potash milligrams per gram. EXAMPLE 14 a. 138 grams of chlorinated polyisobutenylpropionic acid, prepared as hereinabove, were reacted at a temperature of 140°C. with 2.13 grams of pentaerythritol in the presence of 150 grams of xylene and 1.4 grams of paratoluene-sulfonic acid. The reaction was ended when the stoichiometric amount of water was collected. The unreacted pentaerythritol was removed by filtration. The remaining mixture was treated in a rotary evaporator at 130°C. under reduced pressure of 1 mm. Hg. for 30 minutes. The final product had an acid index of 17.25 potash milligrams per gram. b. 110 grams of the product obtained in part a) were reacted with 4.3 grams of tetraethylene pentamine in 50 grams heptane for 1.5 hours at 150°C. The product was then filtered and evaporated at 120°C. under 5 mm. Hg. for 30 minutes. Nitrogen weight percentage in the final product was 1.35%. EXAMPLE 15 a. 200 grams of chlorinated polyisobutenylpropionic acid, produced as hereinabove, were reacted with 10.38 grams of diphenylolpropane in the presence of 150 grams of xylene and 2.1 grams of para-toluene sulfonic acid in accordance with the reaction conditions of Example 14a). b. 142 grams of the product prepared in part a) were reacted with 6.4 grams of tetraethylenepentamine in 50 grams of heptane in accordance with the reaction conditions of Example 14b). Nitrogen weight percentage in the final product was 1.43%. It will be apparent that in the foregoing examples other polyolefin substituted-acid anhydrides, -carboxylic acids, -acid halides, -esters, and the like may be employed, such as polyethylene-, polypropylene- or polypentene-substituted-acid anhydrides, carboxylic acids, acid halides and esters. Other alcohols or hydroxy-aromatic compounds may be employed such as those listed hereinabove in the present specification. Similarly, other ashless or organic bases may be employed, including those listed hereinabove in the present specification. The additive products of the present invention, including the products of the foregoing examples, are desirably employed in lubricating oils, fuel oils and carburants, in amounts of between about 0.01% and 10%, preferably between about 0.1% and 3%, by weight of final product. The foregoing products according to the present invention have been tested with regard to anti-rust and dispersing properties in lubricants. The tests of the dispersing power were conducted according to the stain or spot method described in Volume 1 of A. Schilling's book "Les huiles pour moteurs et le graissage des moteurs" (Oils for motors and motor greasing), edition of 1962, pages 89-90. Stains or spots were achieved with the additive dissolved in a lubricating oil of SAE 30. Sludge was added in order to obtain a content of carbonaceous substances of 0.36%. There are five stains or spots obtained: 1. after heating at 200°C. for 10 minutes 2. after heating at 250°C. for 10 minutes 3. after heating at 200°C. for 10 minutes (at the outset 1% of water was added) 4. after heating at 200°C. during 1 minute (initially 1% of water was added) 5. After adding of 1% of water, in the cold state Readings were made after 48 hours. For every stain or spot, the dispersed sludge percentage is expressed with regard to the oil stain and calculated from the respective diameters. The higher the percentages of dispersed product; the better is the dispersion with regard to sludge. For the products of the foregoing examples the following values were obtained: Example 1 product = 308 Example 2 product = 304 Example 3 product = 312 Example 4 product = 306 Example 5 product = 303 Example 6 product = 308 Example 7 product = 308 Example 8 product = 306 Example 10 product = 301 Example 11 product = 312 Example 14 product = 298 Example 15 product = 308 A comparison was made of the dispersing values obtained by the same test method with other products such as a non-neutralized ester and prior art products commonly used, considered as typical of the present state of the art. Listed below are the values obtained:Product of Example 9 (non-neutralized product < 200Monosuccinimide (Product of ComparativeExample 16, below) 268Bis-succinimide (Product of ComparativeExample 17, below) 274Ester of substituted succinic acid andpentaerythritol (Comparative Example18, below) 265Ester of substituted succinic acid andglycerol (Comparative Example 19, below) 250Ester of substituted succinic acid andphenol (Comparative Example 20, below) < 200Polyisobutenylpropionamide (ComparativeExample 21, below) 263 The mono and bis-succinimides and polyisobutenylpropionamide were tested, on the basis of the same nitrogen content as the products of Examples 1 through 8, 10, 11, 14 and 15 (reference: 1% monosuccinimide in SAE 30 oil). The various prior art succinimide esters listed in the above table were synthesized according to classical esterification processes described hereinbelow and tested, for the same weight as the products of Examples 1 through 8, 10, 11, 14 and 15 (1.8% in SAE 30 oil). COMPARATIVE EXAMPLE 16 -- MONOSUCCINIMIDE PREPARATION 250 grams of polyisobutylene substituted-succinic anhydride having a Pibsa index = 53 were reacted with 18 grams of tetraethylenepentamine at 155°C. for 2 hours, under partial vacuum (about 400 mm. Hg. pressure). Treatment was followed with a vapourization under 20 mm. Hg. pressure for 30 minutes. Nitrogen content of the final product was 2.46%. COMPARATIVE EXAMPLE 17 -- BIS-SUCCINIMIDE PREPARATION 250 Grams of polyisobutylene substituted-succinic anhydride having a Pibsa index = 55 were reacted with 8.6 grams of triethylenetetramine at 155°C. for 2 hours, under a partial vacuum (about 400 mm. Hg. pressure). Treatment was followed by a vapourization under 20 mm. Hg. pressure for 30 minutes. Nitrogen content of the final product was 1.32%. COMPARATIVE EXAMPLE 18 -- PREPARATION OF SUBSTITUTED SUCCINIC ACID AND PENTAERYTHRITOL ESTER 1258 grams of polyisobutylene substituted-succinic anhydride (Pibsa index = 62.5) were reacted with 94 grams of pentaerythritol for 3.5 hours at 135°-145°C. then for 2 hours at 175°-185°C. Unreacted pentaerythritol was removed by filtration. The filtrate constituted ester. COMPARATIVE EXAMPLE 19 -- PREPARATION OF GLYCEROL AND SUBSTITUTED SUCCINIC ANHYDRIDE ESTER 898 grams of polyisobutylene substituted-succinic anhydride with a Pibsa Index = 62.5 were reacted with 46 grams of glycerol for 3 hours at 150°C., then for 3 hours at 190°C. The reaction product was the desired ester. COMPARATIVE EXAMPLE 20 -- PREPARATION OF PHENOL AND SUBSTITUTED SUCCINIC ACID ESTER 898 grams of polyisobutylene substituted-succinic anhydride with a Pibsa index = 62.5 were reacted with 376 grams of phenol in the presence of 190 grams of xylene for 1 hour at 160°-165°C. Afterwards 12.7 grams of p-toluene sulfonic acid were added. The reaction proceeded for 30 minutes at 160°-165°C. This operation was repeated twice. Finally, xylene, residual phenol and catalyst were removed under vacuum (160°-165°C. during 30 minutes -- 10 to 20 mm. Hg. pressure). The final product was the ester. COMPARATIVE EXAMPLE 21 -- POLYISOBUTENYLPROPIONAMIDE 200 grams of polyisobutenylpropionic acid were reacted with 14.55 grams of tetraethylenepentamine in 200 grams of heptane at 160°C. under reflux for 3 hours. After cooling, 100 grams of heptane were added. The mixture was filtered. Heptane was eliminated at 120°C. under 1 mm. Hg. with a rotary evaporator. Nitrogen content of final product was 2.32%. As will be shown below, residual acidity in the lubrication additives of the present invention must be reduced to a minimum, otherwise poor dispersion qualities will result. It has been discovered that sufficient ashless basic compound must be introduced into the product after esterification to impart a nitrogen content of at least about 0.9% in the additive product. For the demonstration which follows there was synthesized a range of products representing various quantities of free acidity in the reaction product at the end of the esterification reaction. Various molar ratios of substituted carboxylic acid or anhydride with respect to hydroxy compound were employed as well as various quantities of catalyst and various ratios of the ashless basic compound. In the tables hereinbelow, residual acidity is represented by free anhydride groups, the same as by groups of free acids. The estimation of this acidity was made in the cases which follow by determination of free anhydride function by means of infrared spectroscopy. First case: ester based on substituted succinic anhydride and pentaerythritol. ______________________________________ Weight percentage ofWeight percentage of free corresponding nitrogenanhydride neutralized by in the final complex Spot testtetraethylene pentamine mixture value______________________________________ 0 0 265 6 0.27 < 20024 0.82 < 20030 1 29535 1.11 31247 1.56 30354 1.65 30565 2.11 309______________________________________ As is seen from the above table, a minimal basicity degree of 0.9% of nitrogen, in the neutralized mixture is necessary to provide good dispersion. This corresponds to a weight percentage of about 30% of residual acid compounds in the mixture resulting from esterification before neutralization. Second case: ester based on substituted succinic anhydride and phenol. ______________________________________Weight percentage of freeanhydride neutralized bytriethylenetetramine or Weight percentage oftetraethylene pentamine with corresponding nitrogen Spotdifferent molar ratios in the final complex testamine/anhydride mixture value______________________________________47 0.71 26547 0.88 27347 1.26 30347 1.56 308______________________________________ Third case: ester based on polyisobutenylpropionic acid and pentaerythritol. ______________________________________ Weight percentage ofWeight percentage of corresponding nitrogenfree acid neutralized by in the final complex Spot testtetraethylenepentamine mixture value______________________________________40 0.85 26965 1.35 308______________________________________ As is shown, it is necessary to have a nitrogen percentage of at least 0.9% by weight in the final complex mixture to obtain good dispersing properties. Finally, for comparison purposes, spot test values achieved with products produced artificially by mixing a neutral ester with a succinimide, a bis-succinimide or a propionamide will be shown below. Numbers 0 -- 20 -- 50 -- 80 -- 100 express weight percentages in mixture. __________________________________________________________________________ Ester of neutral pentaerythri- tol and substituted suc- 0 20 50 80 100 cinic anhydrideMono-succinimide__________________________________________________________________________100 27080 29350 27020 221 0 265__________________________________________________________________________ Ester of neutral pentaerythri- tol and substituted suc- 0 20 50 80 100 cinic anhydrideBis-succinimide__________________________________________________________________________100 28080 25950 21620 227 0 265__________________________________________________________________________ Equal parts by weight of ester of pentaerythritol and polyisobutenylpropionic acid and polyisobutenylpropionamide gave a spot test value of 270. The numbers which are to be compared specially with the ones of Examples 1, 3, 6, 7 and 11 show the superiority of dispersion characteristics of the products according to the invention, which are 308 or 312. The anti-rust characteristics of the products according to the invention have been tested in the laboratory with favorable results. The general tendency has been confirmed by motor tests (sequence II B, gasoline motor V-8 of a 1967 Oldsmobile). The basic information to which the additive was added was composed of a calcium sulfonate, a calcium phenate and a zinc dithiophosphate. The following values expressing average engine rust (AER), were obtained (ideal value 10): Basic formula plus Example 7 product -- AER 8.6 Basic formula plus Example 11 product -- AER 7.9 As a comparison of the prior art, the following value was obtained: Basic formula plus bis-succinimide -- AER 7.2 The entirety of the test results set forth hereinabove shows quite well the important improvement provided by the additives for lubricating oils produced according to the invention and characterizes the technical progress that such new products have achieved. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed.	New lubricating oil additives are provided comprising the reaction product of a hydroxy compound, such as an alcohol or hydroxyaromatic compound, with an aliphatic chain substituted-carboxylic anhydride, acid, chloride, or ester, which aliphatic chain substituent is substantially saturated and contains at least about 30 carbon atoms, said reaction product being neutralized with an ashless basic compound, so that the final product or additive contains at least about 0.9%, up to about 2.5%, by weight of nitrogen. Lubricating oils, fuel oils, and carburants containing the new additives have excellent detergent, dispersing and anti-rust properties.	2
This is a continuation of application Ser. No. 274,127, filed June 16, 1981, which is a continuation of application Ser. No. 183,526 filed Sept. 2, 1980, both abandoned. FIELD OF THE INVENTION The invention relates to the field of liquid chromatography and, more particularly, to an improved method and apparatus by which acid or base reagent is added to chromatographic column effluent to practice separation and detection at distinct and optimized pH conditions. BACKGROUND OF THE INVENTION The very significant potential of using post-column reactors to improve detection in modern liquid chromatography (HPLC) has long been recognized, but little applied. For example, in the publication by Gfeller et al., "Post-Column Derivatization in High-Performance Liquid Chromatography Using the Air Segmentation Principle: Application to Digitalis Glycosides," Journal of Chromatography 142 (1977), pp. 271-281, the authors state: "Although the use of such reaction techniques after column chromatographic separation has been known for more than a decade with classical column techniques (e.g., amino acid analyzers), little has appeared in relation to modern HPLC. One reason is the many technical problems [ ] that still have to be solved." Among specific difficulties that are described in the literature are problems directly involved with state of the the art post-column reactor designs. Thus, Snyder et al., "Introduction to Modern Liquid Chromatography", 2nd Ed. (1979), p. 740, state: "The adaptation of reaction detection to modern LC columns requires careful attention to [] the design of equipment, because extra column effects can be serious. For these reasons reaction detectors have so far found rather limited use in modern LC." Equivalent conclusions are also expressed by Frei et al., "Reaction Detectors in HPLC", Journal of Chromatographic Science, Vol. 17, March 1979, pp. 152-159, wherein the authors state: "the construction of proper reaction detectors comprises a constant struggle against band broadening." In still another recent publication by Jupille, "UV--Visible Absorption Derivatization in Liquid Chromatography", Journal of Chromatographic Science, Vol. 17, March, 1979, pp. 160-167, the author listed among disadvantages of the design or state of the reactors: "a need for hardware modification (with attendant loss in flexibility); and [ ] a risk of band broadening due to post-column mixing volume resulting in loss of resolution." By way of further explanation, the often mentioned problem of avoiding band spreading is interrelated to various factors, among which is the mode for metering reagent. Any lack in consistency of metering produces fluctuations in reagent concentration in the effluent, which shows up as "noise" in the chromatograph developed by the detector. The problem is especially severe where highly concentrated reagent is used, since minute fluctuations can produce high background "noise" levels that severely hamper the sensitivity of detection. While one of the choices of the prior art is to use concentrated reagent to avoid band spreading by sample dilution, the gain may, nevertheless, be offset at least partially by increased background noise levels. Band spreading is also caused by diffusion of sample bands into one another as a function of time. Prior devices inherently appear to obtain poor reagent/effluent mixing, hence, extending the time factor. The deficiency is particularly shown by the description in the literature of reagent/effluent mixing devices as means for promoting faster reactions. Prior solutions to these and other related problems can thus be said to often involve serious drawbacks, e.g., increased "noise", or may be equally as objectionable on the basis of adding too much complexity, e.g., air segmentation methods, to apparatus which has been characterized as already involving inherently disadvantageous "hardware modifications" and "attendant loss of flexibility". An objective of the invention is accordingly to provide an improved liquid chromatographic method and apparatus characterized by the development of an improved post-column reactor for pH adjustment which requires little in the way of hardware modifications. It is particularly an objective hereof to provide such improved method and apparatus which achieve essentially constant "pulseless" metering of acid or base reagent, and, in addition, significantly improved diffusion of the reagent into the chromatographic column effluent. It is still a further objective hereof to provide such apparatus and method wherein sample dilution is minimized without need for resorting to the addition of highly concentrated forms of reagent as a means or requirement, or resorting to other objectionable process or apparatus restrictions. Still a further objective hereof is to provide such method and apparatus, which in contrast with prior art methods and apparatus, are of significantly less cost to use and to maintain. Terms The term "hollow fiber membrane" means an extremely small tube or fiber having an internal diameter of between about 2-1,000 microns, and most preferably, about 50-500 microns, and which has the property to transport mobile reagent in permeation contact with the exterior wall portion of the fiber (or saturated within the fiber wall matrix), while rejecting from transport, at least a detectable amount of a sample species of interest, or a derivative proportional thereto, flowing as a component of liquid chromatographic effluent through the internal bore of the hollow fiber membrane. "Reagent" means a chemical species or combination of species essentially the sole purpose of which, when introduced through the hollow fiber membrane into chromatographic column effluent, is to react chemically, directly or indirectly, with a sample species of interest or an interfering sample species less than perfectly resolved with respect to a sample species of interest, to produce measurable enhancement in the detection of said species of interest, or a monitored proportional derivative thereof, compared to the absence of the hollow fiber membrane/reagent combination. "Mobile" refers to reagent in a state by which it may be permeated or transported through the wall or a wall portion of the hollow fiber membrane. The Invention The above-stated objectives of the invention are achieved by liquid chromatographic apparatus comprising a chromatographic column means, means to add sample to the chromatographic column means, means to add eluent to the chromatographic column means, whereby the sample is eluted through the chromatographic column means, and component species thereof appear in chromatographically displaced form in the effluent of the chromatographic column means, the improvement which comprises, a post-column reactor comprising a hollow fiber membrane through which the effluent of the chromatographic column means is fed to a liquid chromatographic detector, a pH modifying mobile reagent, said hollow fiber being in permeation contact with the mobile reagent for permeation transfer of the reagent into the effluent of the chromatographic column means. A further aspect of the invention is the improved method of analyzing samples by liquid chromatography comprising adding sample to a chromatographic column means, adding eluent to the chromatographic column means effective to chromatographically displace species of the sample from the chromatographic column means, whereby chromatographically displaced sample species appear ultimately in the effluent of the chromatographic column means, the improvement which comprises, feeding the effluent of the chromatographic column means through the internal bore of a hollow fiber membrane, ultimately to a liquid chromatographic detector, and prior to detection, using the hollow fiber membrane for permeation transfer of a mobile reagent into the effluent of the chromatographic column means to enhance the sensitivity of detection of the method by effecting a pH change in the effluent. An essential feature of the invention is the use of single or multiple hollow fiber membranes in conjunction with prior developed liquid chromatographic methods and apparatus. In the preferred device, multiple fibers are potted at each end into a tube sheet for purposes of isolating the inner portion or inner bore of the fibers and also to provide means for connecting the inner portion of the fibers to standard liquid chromatographic fittings. The center section of the hollow fiber "bundle", which may be coiled to conserve space, is immersed within mobile reagent. As such, the device is readily combined with standard and commercial forms of liquid chromatographic apparatus with minimal need for basic modification in the hardware. Hollow fiber membranes useful in the practice of the invention are characterized by a molecularly porous wall structure obtained as an inherent property of the material used to make the fiber, or obtained as product of the manufacturing process, or a combination of both. The invention makes no claim, as such, to inventing the hollow fiber membrane structure per se. Typically used in practicing the method and apparatus of the invention are thus commercial hollow fiber membranes developed for other applications, and which are adaptable to the invention. Among properties desired of the hollow fiber membrane, in addition to the ability to contain and transport reagent, and resist transport of at least part of the sample, is tolerance to contact with the various liquids to which the membrane is exposed. Particularly useful in this respect are porous cellulose membranes prepared such as by the method of U.S. Pat. No. 3,546,209. Such membranes may be either isotropic or anisotropic in structure. The transport properties of this type of membrane are produced typically by fabricating discretely sized pores piercing the fiber wall, e.g., by "pushing aside" the membrane material to form the pore structure. As such, the permeation characteristics are basically that of size selection and may be broadly applied to permeate widely diverse reagent species. Synthetic polymeric membranes, such as produced typically from polyolefins and also silicone rubber, as well as a considerable group of other polymeric materials, may be adapted for use in the invention. Particularly useful are charged ion-exchange hollow fiber membranes produced by sulfonation or amination processes in order to obtain "Donnan exclusion" rejection properties of ionic species. Permeation through such membranes is often typically through a "tortuous" path defined in the molecular spaces between polymer molecules. The transport and selective properties of the solid matrix polymeric hollow fiber is thus often very specific and thus requires careful selection with reagent and sample in mind. Specific examples of this type of the membrane are detailed below with respect to some of the very important reagents. The "leakage" characteristics of hollow fiber membranes used in the invention are oftentimes not highly critical. For example, leakage through the fiber wall of other than sample is often, if not inconsequential, not a phenomenon that will severely hamper the analysis. Thus, eluents used in the invention are generally characterized as noninterfering or substantially noninterfering. Reagent diluents, where used, may be selected for the same properties. Accordingly, leakage of these characterized components, assuming there is a net transfer one way or the other, may, at most, produce a dilution on the sample in the chromatographic effluent. Assuming a net loss of chromatographic effluent through any such transfer, a desirable concentration of the sample may in fact result from beneficial leakage phenomena producing higher detection sensitivity. In addition, while it would be desired to have a hollow fiber membrane that rejected sample in the perfect sense, such is neither an absolute or essential requirement. While too much loss of sample can be consequential to the sensitivity of the analysis, substantial loss of sample does not necessarily mean severely detrimental results will occur. Thus, for illustrative example, 90 percent leakage of sample would not necessarily preclude highly sensitive analysis from being performed where the gain of sensitivity by the method is on the order of a thousandfold, which is not an unusual result possible with reagent addition methods. Since the amount of reagent necessary to achieve highly dramatic improvement in detection sensitivity can be very small, the selective transport properties of the membrane may in fact favor transport of the sample. That is, a greater leakage of sample than premeation of reagent may be experienced by use of a particular membrane, while at the same time obtaining enhancement in sensitivity of detection. Thus, selective transport properties of the hollow fiber membrane, favoring the reagent, is not an essential requirement of the invention in its broadest sense. In respect to band spreading produced by dilution factors, or adding liquid volume to the chromatographic effluent, the invention has a very important advantage over prior art reagent addition methods. Thus, while it is contemplated that there is often a significant leakage of the nonactive component of the reagent into the chromatographic effluent, since other than perfect permselective qualities are present in hollow fibers, there is at the same time the mentioned ability of the fiber to extract fluid from the effluent, so that a net exchange of fluid volume is involved. For membranes which possess good sample rejection properties, it is thus possible to minimize dilution volume without resorting to difficult procedures that severely restrict the method. In order to minimize band spreading due to geometry and flow pattern factors using the method and apparatus of the invention, it is desirable that if multiple hollow fibers be used, they each produce the same resistance to flow and, consequently, as the effluent stream is divided and flows in the multiple passages of the individual fibers, flow proceeds at a uniform rate. Thus, with flow dwell time in the individual fibers being substantially constant, tendency for band spreading is greatly reduced. This is typically achieved by using multiple fibers of the same internal diameter and length. Obviously, to overcome the effect entirely, fibers could be matched to produce exactly equivalent flow characteristics. Also as a general rule, other considerations aside, the larger the fiber, the greater the tendency to produce band spreading by inherent fluid drag at the fiber wall/flow interface, hence producing an effect that if accentuated enough, or prolonged for long enough, can cause loss of resolution. The effect is minimized by using multiple fibers of extremely small diameters, and, which by means of larger surface area can pass reagent more quickly, frequently permitting the use of a shorter path of travel, and hence minimal band spreading based on diffusion of sample bands into one another as a factor of time. The rate of diffusion of the reagent in the chromatographic effluent is also effectively improved using small multiple hollow fiber membranes. Hence, very significant advantage in critical parameters is often achieved by the use of a post-column reactor design based on the use of multiple hollow fibers having satisfactory sample rejection properties, and connected in parallel between the chromatographic column means and detector. Highly suited for use in the multiple fiber device are fibers of between about 100-300 microns in internal diameter for use in conventional bore liquid chromatography. In conjunction with microbore liquid chromatography such as described by Scott et al., Journal of Chromatography, Vol. 169, pg. 51 (1979) incorporated herein by reference, extremely small fibers in the range as low as the current manufacturing limit of about 20 microns I.D. would be usable. The wall thickness of the fibers is not always highly critical to rate of permeability as explained in U.S. Pat. No. 3,808,267, incorporated herein by reference. Generally, the wall thickness of fibers as used in the invention will be between about 5-250 microns. The length of the fibers can additionally vary depending on permeation and/or diffusion rates through the fiber wall. Generally, it is contemplated to use fibers of from about 10 centimeters to 200 centimeters in length, as a nonlimiting illustration. The restriction on length (and minimum I.D.) is ultimately a function of pressure drop through the fibers and back pressure on the fibers. Too much back pressure can rupture the fibers, thus limiting the pumping pressure. This can be compensated for, however, by equilibrating the pressure about the fibers with the internal pressure, such as by maintaining the fibers in a pressurized vessel. By taking the latter precautions, the length of the fibers may be increased to the point that resolution of the chromatographically displaced species is not too adversely affected. The fibers or a portion thereof are in permeation contact with mobile reagent, the temperature, differential pressure with chromatographic effluent, and concentration of which significantly affect premeation rates in accordance with known membrane transfer phenomena. The reagent comprises, e.g., a pure liquid, pure gas or solution of reagent in a diluent or carrier whereby the reagent is mobile and may thus permeate the fiber wall. In some cases, an inert diluent such as methylene chloride is used which modifies the membrane such as by diffusion into the membrane to increase the rate of permeation of the reagent, also in accordance with known membrane phenomena. Other types of liquids, such as water or acetonitrile, are typically used as the reagent diluent. In addition, it is also possible to use reagent, particularly ionic species, attached to active ion exchange sites of solutions or gels of ion-exchange resin, or agitated ion exchanged beads, in order to produce mobile reagent. This embodiment may be used, for example, with a charged ion-exchange hollow fiber membrane, whereby the reagent ion is exchanged with the exchangeable ion of the membrane and, thus, ultimately diffuses into the chromatographic column effluent. The embodiment is particularly useful wherever it would be desired that the ions similarly extracted from the chromatographic effluent, by the charged hollow fiber membrane, would be detrimental to detection. A means would thus be provided for minimizing return leakage. In addition, the embodiment can be used to prevent transfer of the relatively large polymeric counter ion of a given ionic reagent particularly where the counter ion would interfere or otherwise be detrimental to the analysis. Two forms of reagent reservoirs or containers are particularly contemplated. The preferred form is generally described as a static reservoir, although the reagent may be agitated or stirred in order to prevent a concentration differential from occurring. Alternatively, a dynamic flow of the reagent, wherein continuously fresh reagent is pumped into contact with the fibers, may be used. The latter embodiment has advantages where contamination of the reservoir by leaking chromatographic effluent would be detrimental to the analysis. In such an embodiment, the fibers are placed, e.g., co-axially within a preferably flexible tube container to define an annular space between the fiber and inner wall of the tube. The fibers are potted at each end to isolate the inner bores of the fibers for connection to chromatographic fittings similarly as with respect to a static reservoir. Spaced tees are connected at the end of the tube container and reagent is continuously pumped into the annular space, most effectively in counter flow to the flow of the chromatographic effluent. Because of less complexity, and typically very comparable performance to the dynamic reservoir embodiment, the static reservoir is to be preferred. Because the dilution of leaking sample into the relatively large reservoir of reagent produces an extremely dilute solution of a possible interfering species, the effect at most may be reflected as a slightly varying base line over a period of use. Ordinarily such would thus not justify the additional complexity associated with a dynamic reservoir embodiment. The reaction kinetics of reagent addition methods, as well as prior developed reagents, are considered background technology to the invention and useful in its practice. Thus, the specific reagents and reactions developed for detection purposes and used in the invention are drawn from prior art sources. A fairly detailed listing of reactions considered suitable for use in post-column effluent reaction procedures is given by Snyder et al., supra, pages 740-746, herein incorporated by reference. Also incorporated by reference are the similar teachings of the prior cited references by Gfeller et al.; Frei et al.; and Jupille, together with a publication by Vance Nau et al., "Application of Microporous Membranes to Chemiluminescence", Analytical Chemistry, Vol. 51, No. 3, March 1979, pp. 424-428. Favorable reaction condition necessary to promote the reaction must of course be present with this invention as with other reagent addition modes. Thus, reactions which require a major proportion of water in the final reaction mixture will generally require that aqueous eluents be used. The latter requirement is generally met with respect to ion-exchange and reverse-phase liquid chromatographic separation methods, or similar liquid chromatographic methods which employ an aqueous eluent or mobile phase in which the reagent is at least partially miscible. Similarly, for liquid chromatographic techniques such as normal phase chromatography, the invention is typically limited to the selection of reagents that can proceed in or require an organic solution in which the reagent is at least partially miscible. For slow reactions, elevated temperatures are imparted to the reaction mixture such as by means of a heated reaction delay loop which provides added residence time. Liquid chromatographic detectors useful in the practice of the invention are particularly advantageously photometers, spectrophotometers and fluorometers used together with reagents which alter or produce light absorbance of sample species in the chromatographic effluent or which produce fluorescing derivative products. Among other liquid chromatographic detectors beneficially used in the mode of the invention are differential refractormeters, electrochemical detectors, radioactive detectors, and conductivity detectors, given for illustrative example only. THE DRAWING Yet further objects and advantages of the invention will, in part, be pointed out, and, in part, be apparent from the following detailed description taken together with the accompanying Drawing wherein: FIG. 1 is an elevational view of apparatus for performing liquid chromatography using post-column reagent addition in accordance with the principles and teachings of the present invention. FIG. 2 is an enlarged cross-sectional view showing additional detail of the post-column reactor used in the FIG. 1 apparatus; and FIG. 3 is a view like FIG. 2 showing a modified form of the post-column reactor. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIG. 1, there is shown a schematic view of liquid chromatographic apparatus which is desirably used in practicing the invention, and which comprises a chromatographic column or column means 10. The chromatographic column comprises a housed separating means typically in the form of a particulate packing or gel through which sample is eluted to separate the sample into component species. Diverse types of separating means may be used to construct a suitable chromatographic column, as described extensively, e.g., by Snyder et al., incorporated herein by reference. Preferred means to add eluent or mobile phase to chromatographic column 10 comprises an eluent reservoir 12 containing eluent solution 14, the latter which is withdrawn from the reservoir by a chromatographic pump 16 equipped with an optional pulse damping coil 18. Preferred means for adding sample comprise, e.g., a syringe loadable sample injection valve 20. Sample added to the system at valve 20 is swept through the apparatus by the pumped eluent solution through an optional guard column 22 to chromatographic column 10. The sample is eluted through column 10, and component species thereof thus ultimately appear chromatographically displaced in the chromatographic column effluent which is delivered to the reagent addition device or post-column reactor 24, described in further detail below. The reagent addition device or reactor is optionally followed by a reaction delay coil or functionally equivalent element used whenever necessary to provide added reaction time vis-a-vis the species to be derivatized. Optionally, both or either the reagent solution or delay coil is maintained at a controlled temperature by suitable temperature control means, most simply, a temperature controlled plate which heats solution or fluid in which the delay coil is immersed; and/or which heats the reagent solution. The delay coil is ultimately followed by a detector 26 of a type suited for liquid chromatography. In the detector, the effluent produces an electrical signal proportional to the property monitored such as light absorbance, fluorescence, etc., and which is directed from the detector ultimately to a suitable visual recorder 28 such as strip chart recorder, integrator, and the like, well-known to the art field. Referring to FIG. 2, a preferred form of reagent addition device, based on a simplicity factor, and acceptable performance for a great number of reagent addition reactions, is the design shown here. This is the "static" reservoir design which comprises basically a reservoir or reagent container or container means 30 preferably of glass or similarly inert material. Contained in the reservoir is mobile reagent 32. Reagent is periodically changed through a screw-cap or other suitable closure 34. Hollow fibers 36 are suspended in the reagent, between the points of an effluent in feed connection 38 and out feed connection 40. Each such connection is manufactured as follows: Openings 42 are drilled or otherwise formed in the cap, to which is attached a chromatographic adapter 44. The attachment is made by use of general purpose epoxy glue shown at 46. Chromatographic tubing 48 bringing chromatographic column effluent in is attached to the threaded nipple 50 of adapter 44, using a standard liquid chromatographic connecting nut and ferrule 52, 54. The out feed similarly connects to chromatographic tubing 56 leading to detector 28 through a similarly designated connecting nut 52 and ferrule 54. A preferred form of fixing the fiber ends into the female part of adapter 44 is to mold a fitting 58 about the end portions 60 of the fibers. This fitting is made by using a RTV compound, e.g., Silastic brand mold making rubber J-RTV, to make a mold, using as the form for the mold, the commercial fitting which is to be duplicated. For an epoxy system, the fibers are threaded through the mold by drilling a small diameter hole for the threading purpose. The epoxy, e.g., Dow 331 Epoxy Resin/Ancamine LT Hardener, is poured into the mold and cured, with the fibers "wetted", or dry depending whether fiber swelling is expected in the end use application. After removal from the mold, the fiber ends are trimmed as required. A fiber coating layer 62, e.g., Silastic 730 RTV Fluorosilicone Sealant (from Dow Corning Corp.) is preferably applied in the area immediately adjacent the fitting to avoid fiber point stress, and thus minimize damage as may occur such as in the physical handling of the fibers. The epoxy resin system is useful for aqueous reagent and eluent systems, certain aromatic solvents, and some hydrocarbons. For reagent solution or eluents which chemically attack epoxies, there is used in preference and for longer life, a Silastic Brand J-RTV material for constructing fitting 58 which otherwise is manufactured similar to the epoxy fitting. Fitting 58 is also suitably manufactured using a hollow commercial fitting through which the fibers are passed and which is filled with a RTV material, e.g., 730 RTV sealant, and the fill cured. The latter thus basically consists of the commercial chromatographic fitting with the ends of the fibers potted inside the hollow portion of the fitting by the in situ curing process using the described RTV material, or a substitute in situ curable substance. A preferred embodiment of the construction of a reagent addition device having the fibers immersed in counter flowing mobile reagent is illustrated in FIG. 3. This device is constructed of a center section of stainless steel tubing or tube container means or jacket means 68 through which a bundle of hollow fibers is inserted by suction or by gluing the end of a length of thread to a fiber bundle and pulling the fibers through the jacket means using water as the lubricant. A tee or tee fitting 70 is affixed to opposite ends, respectively, of the jacket means 68 using tube nuts 72 with ferrules 74 to make the attachment. Exposed portions of the hollow fibers (outwardly of each tee) are dried and inserted into sealing tubes or tube elements 76, respectively, also preferably of stainless steel. A section of about six inches of fibers is left exposed between the sealing tube elements and tees 70 and the exposed fiber sections are coated with a suitable sealant, e.g., Silastic 732 RTV silicone rubber as indicated at areas 66, after which the sealing tubes are pushed down and coupled to the tees using tube nuts 78 and ferrules 80. Additional RTV sealant is injected into the sealing tubes using a blunt 20 gauge needle to completely fill each sealing tube but taking care not to force excess rubber into the tees. The RTV sealant is allowed to cure for 10 minutes to promote initial bonding and curing is completed with the fiber "wetted" or dry as the end-use application demands, and a razor blade used to cut the fiber bundle off flush with the end of the sealing tube. The device may then be coupled into the apparatus of FIG. 1, e.g., using reducing union assemblies 82, similarly is connected to a reservoir and pump means for supplying reagent, supplied through chromatographic tubing 84 and 86, respectively. These latter connections may be of the same type described, supra, using a tube element 88 joined at one end to tees 70 through tube nuts 90 and ferrules 92; and at the opposite end joined, respectively, to the reagent inlet and outlet 84, 86 through reducing union assemblies 94. The device as assembled defines contiguous flow channels comprising, respectively, the collective bores of the hollow fibers, and the spaces exterior of the fibers within jacket means 68 and which communicate, respectively, with chromatographic column 10 and the reagent supply source (not shown). The described reagent addition devices operate by receiving the effluent of the chromatographic column which is thus routed internally through the hollow fibers. Simultaneously, solution containing mobile reagent (static or in the dynamic form) is contacted with the exterior surface of the hollow fibers, thus causing permeation of the reagent into the chromatographic effluent. The invention is still further illustrated by reference to the specific teaching examples below. EXAMPLE 1--HOLLOW FIBER MEMBRANES Various hollow fiber membranes are used to construct reagent addition devices for use in the invention using the preferred static reservoir design. These include: Device (A) A device constructed of hollow fiber strands initially (prior to sulfonation) of 380 μO.D. and 300 μI.D., prepared by extrusion through a spinverette in the known manner. The fiber is formed of Product Code No. 4005 low density polyethylene, commercially available from The Dow Chemical Company. The fibers for purposes of sulfonation are wound on a glass mandrel (cage) and secured with Teflon tape. Since sulfonation weakens the fibers, it is desired that portions of the fibers where the fittings are to be attached are not subject to the sulfonating process. This is accomplished by looping discrete sections at a 90° angle to the circumferentially wound fiber sections to form a loop offset from the mandrel end. Using a Teflon cord attached to the loop, the fibers are suspended in a 3-neck/one liter flask equipped with a condenser and heating mandrel. A sufficient volume of a 10% solution (v/v) of chlorosulfonic acid in methylene chloride is added to the flask to immerse the fibers (but not the looped end) and the solution is heated to reflux conditions (42° C.) and sulfonated for approximately 30 minutes. The fibers are retrieved and placed in methylene chloride and soaked for 1/2 hour followed by washing with deionized water. The loops are cut to provide unsulfonated ends for potting in fittings 58. Capacity is approximately 1 meg/gm. The device as constructed uses preferably 7 sulfonated fiber strands each 8 inches long. Device (B) A device constucted using 4 hollow fiber strands 8 inches long, 300 microns O.D., 230 microns I.D., obtained under the trade designation SR-α/751-7010 from Bio-Rad Laboratories. The fibers are believed to comprise a copolymer of 40% α-methylstyrene/60% polymethyl siloxane. Device (C) A device prepared using the basic sulfonation procedure and material of Device (A), supra, prepared using 16 fiber strands each 8 inches long, with a capacity of about 0.5 meg/gm, and final dimensions of approximately 375 micron O.D., 300 micron I.D. Device (D) Similar fibers to Device (A) are used in this device using 9 fiber strands, each about 10 inches long, sulfonated to achieve a capacity of about 0.7 meg/gm. Device (E) A device prepared from microporous cellulose hollow fibers, obtained commercially as a product of Spectrum Medical Industries, Inc., designated by Manufacturers Order No. 132272, and sold under the trademark SPECTRA/POR hollow fibre (HF) membrane. The device consists of 10 fiber strands, each 6 inches long, described as having a molecular weight cutoff in the range of 500-2000. EXAMPLE 2--NITROPHENOL DETECTION Separation of various nitrophenols using a silica based column, requires acid eluent pH conditions (about pH 6) for acceptable component resolution and/or for reason of column pH limitations. While the nitrophenols absorb at 280 nm, organic interferences in the sample matrix produce poor detection sensitivity. This experiment illustrates an excellent solution to this analysis problem is available by producing a pH change through treating the chromatographic column effluent with NH 3 reagent, in order to produce derivative sample species which will absorb at a distinct wavelength that avoids matrix interferences. The experiment uses Device (A), and as the reagent, a solution of 30% ammonium hydroxide in water. The experiment is conducted under the further conditions as follows: Aqueous eluent of 12 volume percent methanol, 0.08 M sodium perchlorate, 0.04 M ammonium acetate, adjusted to pH 6.1 with glacial acetic acid is pumped at 1.8 ml/min using a Milton Roy mini-pump through a Rheodyne 7120 sample injection valve with a 100 μl sample loop. The sample consisting of an identified organic matrix spiked with nitrophenols of interest is added to a Whatman Partisil Sax 10/25 chromatographic column, and detected using a LDC 1203 (Laboratory Data Control) photometer at 410 nm detection wavelength. A Spectro-Physics SP-4100 computing integrator is used for signal processing and computation. Typical nitrophenols detectable by the system include 2,4,6-trinitrophenol, 2-sec butyl-4-6-dinitrophenol, 3-sec buty-2-hydroxy 5 nitrobenzene sulfonic acid and 3-sec butyl-4 hydroxy 5 nitrobenzene sulfonic acid. Detection limits for these compounds are at sub-ppm levels with no sample preparation. At this detection wavelength and pH change, the system is found to be very selective. In a similar experiment to the above, 2,4,6-trinitrophenol species of interest is detected in admixture with co-eluting 2-sec-butyl-4,6-dinitrophenol, using as the reagent 2 M HCl in water. The chromatographic eluent is modified to a pH of about 2 (eluent pH 6.1). The pH adjustment selectively attenuates the dinitrophenol peak, to produce resolution and detection of the trinitrophenol species of interest in the sub-ppm range. EXAMPLE 3--FLUORESCAMINE ADDITION The fluorescamine reaction is a particularly important reagent addition reaction used, e.g., in the detection of primary amines. This experiment illustrates a specific example of the fluorescamine reaction as used in the mode of the invention. The experiment is conducted using as the reagent additive device, Device (B), and as the reagent in which the fibers are immersed, a 2 mg/ml solution of fluorescamine in acetonitrile. A Varian 8500 chromatographic pump is used to pump 30 volume percent acetonitrile in water eluent solution containing 0.01 M ammonium acetate at 1 ml/min. A Rheodyne 7120 Injector (20 μl loop) is used to add a sample standard (1 ppm α-amino toluene in water) to a Waters μ-C-18 analytical HPLC column. The sample is detected using a duPont 836 fluorescence detector operated at 390 nm, 475 nm, excitation and emission wavelengths, respectively. A strong peak (offscale) is obtained at the ppm sample concentration level. EXAMPLE 4--NINHYDRIN REACTION The ninhydrin reaction is an excellent tool used in the detection, e.g., of amino acids, and is commonly utilized in commercial amino acid analyzers to develop blue color species derivatives which may be detected by a visible light photometer. The reaction can be beneficially utilized in the mode of the invention as illustrated in this Example. Under the conditions of this experiment, eluent of 0.02 M citric acid in water adjusted to pH 4.0 with NaOH, is pumped by a Milton-Roy minipump at 0.52 ml/min through a Rheodyne 7120 injection valve equipped with a 200 μl loop where periodic injections of 50 ppm glycine are made to simulate peaks coming off of an analytical separation column. Device (C) is employed for the reagent addition purpose, using as the reagent, 100 ml of 10% ninhydrin solution in water. A hot plate is used to maintain the reagent at a temperature of 90° C.±5°. The ninhydrin treated solution is subsequently passed through a heated delay coil (2 meter, coiled Teflon tubing maintained at 90° C.) to provide a 3-minute delay for the reaction to occur. The reactor effluent is monitored using a Perkin-Elmer LC-55 UV/VIS absorption photometer operated at 600 nm. The peak of blue absorbance due to the ninhydrin-amino acid reaction product is recorded on a Sargent Welch Model SG Recorder. Excellent peaks are produced showing detection limits at the ppm level. Approximately 75% of the amino acid is estimated to have reacted under the conditions employed. No discoloration of the ninhydrin reagent solution is noted during the course of consecutive injections of sample. EXAMPLE 5--IODIDE REACTION Peroxides and other relatively strong oxidants will oxidize I - to I 2 to form highly colored I 3 - in the presence of excess I - . The reaction is useful, e.g., to determine the presence of peroxides or other strong oxidants in industrial process streams and products. As an illustration of the use of this reaction in the inventive mode, eluent of 100 mg/liter (NH 4 ) 2 MoO 4 in water, pH 5, is pumped at 1 ml/min into reagent additive Device (D), using as the reagent, stirred 1.0 M potassium iodide in water maintained at 54° C.+0.2° C. Repeated injections of aqueous hydrogen peroxide samples are made using a Rheodyne sample injection valve, 50 μl sample loop size (a separating column is not used in this experiment). The sample is detected using a duPont 837 Visible UV photometer set at 375 nm. The recorded data is shown in the following Table. TABLE______________________________________Sample Size Attenuation Peak Height Att'n × Peak______________________________________H.sub.2 O.sub.231.6 ppm 32× 208 6650100 ppm 128× 126 16130316 ppm 256× 108 2765010 ppm 32× 70 224010 ppm 16× 139 22243.1 ppm 16× 49 7843.1 ppm 8× 98.5 7883.1 ppm 4× 197.5 7901.0 ppm 4× 62.5 2500.3 ppm 4× 19.5 78______________________________________ The detection limit, calculated from the data, is estimated to be about 0.1 ppm. The method is considered to show linearity up to about 50 ppm hydrogen peroxide. EXAMPLE 6--CELLULOSE FIBERS The iodide reaction may similarly be applied to detect species e.g., NO 2 - , ClO 3 - , bleach and Cl 2 . This example illustrates the detection of sodium nitrite, using the cellulose hollow fiber (Device (E), and using as the reagent, 0.1 N potassium iodide in water. In order to demonstrate the feasibility of the reactor-detector combination, sample standards of 100 to 1000 ppm, 20 μl sample injection size, are injected into pumped water eluent flowing at 1 ml/min, fed through Device (E), and the effluent of the Device monitored by a Perkin-Elmer LC-55 photometer set at 360 nm. Although not considered optimized, excellent detector sensitivity response is achieved, producing an estimated detection sensitivity comparable to that of hydrogen peroxide in the preceding example.	Reagent is added to liquid chromatographic effluent to increase detection sensitivity of sample bands, or to enhance sensitivity with respect to interfering bands which overlap sample bands of interest, using one or more hollow fibers immersed within mobile reagent which is permeated through the walls of the fibers and, thus, ultimately diffused into the column effluent.	6
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a branching apparatus for a paper-web threading guide disposed in a threading path in a paper-web threading apparatus of a rotary press, through which a paper web is passed for printing. 2. Discussion of the Related Art Conventional branching apparatuses disposed in a paper-web threading guide of a rotary press are disclosed in, for example, Japanese Patent Publication (kokoku) No. 6-88695 and Japanese Patent Application Laid-Open (kokai) No. 5-77390. In these apparatuses, a branching block having a plurality of branching paths and serving as a branching apparatus, a stationary threading guide having a guide groove and located on the upstream side of the branching block, and a stationary threading guide having a plurality of guide grooves and located on the downstream side of the branching block are disposed along a threading path in a separated manner. The branching block having a plurality of branching paths is connected to drive means composed of a single-or double-acting type fluid cylinder. The branching block is moved to a plurality of positions through operation of the fluid cylinder so as to cause a desired one of the plurality of branching paths to communicate with the guide groove of the upstream stationary threading guide. With this operation, the guide groove of the upstream stationary threading guide communicates with a selected desired one of the plurality of guide grooves of the downstream stationary threading guide via the branching path. The branching block may be in the form of a linear motion type or a rotary type. In the former case, the branching block is moved along a straight line through operation of the fluid cylinder. In the latter case, the branching block is rotated through operation of the fluid cylinder. Upon operation of the branching apparatus of the threading guide, a threading member is caused to travel from the guide groove of the upstream stationary threading guide to the selected groove of the downstream stationary threading guide, so that the threading member guides a paper web to travel along a selected predetermined threading path. In the above-described conventional branching apparatus for a threading guide, the branching block having a plurality of branching paths and serving as the branching apparatus is disposed movably between the upstream and the downstream stationary threading guides such that it is in contact with both stationary threading guides. Therefore, in order to allow the threading member to travel smoothly through the guide groove of the upstream stationary threading guide, the branching path of the branching block, and the guide groove of the downstream stationary threading guide, the end surfaces of the branching block must be movable relative to and in close contact with the end surfaces of the upstream and downstream stationary threading guides. Moreover, at each of the plurality of positions to which the branching block is moved, the selected branching path must correspond accurately, at its opposite ends, to the respective guide grooves of the upstream and downstream stationary threading guides. If the above-described requirements are not satisfied, the tip end of the traveling threading member is caught by slight steps formed between the end surfaces of the upstream and downstream stationary threading guides and the end surfaces of the branching block, so that the traveling of the threading member is hindered. However, in order to ensure that the end surfaces of the branching block are movable relative to the end surfaces of the upstream and downstream stationary threading guides in a closely contacted manner and that each selected branching path corresponds accurately, at its opposite ends, to the guide grooves of the upstream and downstream stationary threading guides, considerably high accuracy is needed in machining and assembly of the above-described components and in movement of the branching block provided by the drive means composed of the fluid cylinder. The realization of such high accuracy is very difficult, partially because of the small widths of the guide grooves and the branching paths. This also increases production costs of the apparatus. When the number of branches increases, the number of the branching paths of the branching block and the size of the branching block also increase, so that the branching apparatus for the threading guide must move the branching block having an increased size. Accordingly, the branching apparatus inevitably becomes bigger. Accordingly, there arises an additional problem that a larger space is required in order to install the branching apparatus in the threading guide. SUMMARY OF THE INVENTION An object of the present invention is to completely solve the above-described problems involved in the conventional branching apparatus for a threading guide. Another object of the present invention is to provide a branching apparatus for a threading guide of a rotary press, which ensures smooth traveling of a threading member and which is simple and compact. In order to achieve the above objects, the present invention provides an improved branching apparatus for a threading guide of a rotary press. The branching apparatus is provided in a paper-web threading apparatus in which, in order to thread a paper web into a threading path of the rotary press, threading guides are disposed at side portions of the threading path to extend therealong, thereby forming a threading-member traveling path through which a threading member can travel. The branching apparatus includes a branch threading guide in which a plurality of downstream threading-member traveling paths are formed such that they communicate with a single upstream threading-member traveling path via respective branching points, shifters disposed in the vicinity of the branch threading guide and having guide edges which operate at the branching points of the branch threading guide so as to guide the threading member to a selected downstream threading-member traveling path while closing the unselected downstream threading-member traveling path or paths, and drive means for moving the shifters so as to selectively open and close the downstream threading-member traveling paths. Preferably, on the upstream introduction side, the guide edge of each shifter has a slanted or arcuate shape so that the distance between the guide edge and the threading-member traveling path increases toward upstream side. Preferably, two pairs of shifters are disposed along two parallel planes so as to restrict the widthwise sides of the forward end portion of the threading member, thereby introducing the threading member into a selected downstream threading-member traveling path. Alternatively, a single pair of shifters are disposed along a single plane such that they penetrate the branch threading guide, the shifters restricting the widthwise center portion of the forward end portion of the threading ember, thereby introducing the threading member into a selected downstream threading-member traveling path. In the above-described branching apparatus for a threading guide of a rotary press, in the middle of a threading path starting from an upstream paper feed section and ending at a downstream folding section, a threading member bonded to the forward end of each transversal edge of a paper web travels along a predetermined threading-member traveling path while being guided by the threading guides. As a result, the paper web is threaded along a predetermined threading path. At a branching point of the threading path, i.e., at a branching point of the threading-member traveling path, the threading member travels toward a threading-member traveling path selected by the branching apparatus, so that the paper web is threaded along a selected threading path. The selection of a threading-member traveling path at the branching point is performed through movement of the shifters to a desired position by the drive means. The threading member that had traveled along the upstream threading-member traveling path while having been guided by the threading guide and that has reached the branching portion of the threading guide is prevented from entering the unselected downstream threading-member traveling path or paths that are closed by the guide edge of the shifter, but is allowed to enter the selected downstream threading-member traveling path into which the threading member is guided by the guide edge of the shifter, so that the threading member travels along the selected downstream threading-member traveling path. On the upstream introduction side, the guide edge of the shifter has a slanted or arcuate shape so that the distance between the guide edge and the threading-member traveling path increases toward the upstream side. Therefore, the tip end of the traveling threading member engages smoothly with the guide edge of the shifter when the threading member is guided by the guide edge of the shifter. In the branching apparatus for a paper-web threading apparatus of a rotary press according to the present invention, a threading guide in a single path region and a plurality of threading guides in branching regions are continuously formed to have simple shapes and no steps are formed in the threading guide. Accordingly, no difficulty arises in manufacture, and there is no possibility that the tip end of a traveling threading member becomes caught due to a step in the threading guide. Moreover, selection of a threading-member traveling path at the branching point is carried out by means of a small shifter, which is disposed in the vicinity of the branching point, as a part different from the threading guide. Accordingly, it is sufficient for the shifter to be position-adjusted with relatively low accuracy, thus facilitating assembly of the apparatus. In addition, since the selection of a threading-member traveling path is not performed through movement of the threading guide but is performed through movement of the shifters, the branching apparatus itself can be made compact so as to reduce the installation space. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Various other objects, features and many of the attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description of the preferred embodiments when considered in connection with the accompanying drawings, in which: FIGS. 1A and 1B each show a front view of a threading branching apparatus according to a first embodiment of the present invention; FIG. 2A is a sectional view taken along line IIA--IIA in FIG. 1A; FIG. 2B is a sectional view taken along line IIB--IIB in FIG. 1B; FIG. 3 is a sectional view taken along line III--III in FIG. 1A; FIG. 4 is a sectional view taken along line IIA--IIA in FIG. 1A showing a first modification (A) of the first embodiment of the present invention; FIG. 5 is a sectional view taken along line IIA--IIA in FIG. 1A showing a second modification (B) of the first embodiment of the present invention; FIG. 6 shows a front view of a threading branching apparatus according to a second embodiment of the present invention; FIG. 7 is a sectional view taken along line V--V in FIG. 6; FIG. 8 is a sectioned partial view taken along line V--V in FIG. 6 showing a modification of the second embodiment of the present invention; FIG. 9 is a front view showing an example in which the threading branching apparatus according to the first or second embodiment of the present invention is applied to multiple branching; FIG. 10 is a front view of a threading branching apparatus according to a third embodiment of the present invention; and FIG. 11 is a perspective view of a threading member used in the embodiments of the present invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Branching apparatuses for a threading guide of a rotary press according to embodiments of the present invention will now be described with reference to the drawings. First, a description will be given of a branching apparatus for a threading guide of a rotary press according to a first embodiment of the present invention. It is to be noted that, in the descriptions, directions (upward, downward, rightward, and leftward) denote directions in FIGS. 1A and 1B, and that in each drawing the direction of a threading-member traveling path after a branching point represents an exemplary direction. A threading guide is disposed on the inner surface of a frame of the rotary press along a threading path that extends in a range from an upstream paper feed section to a downstream folding section. As shown in FIGS. 1A, 1B, 2A, and 2B, a long bracket 2 having an inverted-L-shaped cross section is attached to each inner surface of the frame 1 of the rotary press such that the bracket 2 extends in the direction of the threading path. That is, the edge of one side portion of the bracket 2 is fixed to the corresponding inner surface of the frame 1, while the other side portion of the bracket 2 forms a vertical portion 2a having a flat surface separated from the corresponding inner surface of the frame. In the threading guide, there exists an upstream (left side) single path region 31 and a downstream (right side) branch region 32, which is connected to the single path region 31 and in which a single threading path is branched into a plurality of threading paths. A plurality of single path regions follow the branch region 32, and a different branch region 32 is connected to each single path region 31, as shown in FIG. 9, thereby increasing the number of branches. Each single path region 31 of the threading guide is supported by guide support brackets 4 disposed at proper intervals in the threading direction, so that the entire threading guide is mounted to the bracket 2, i.e., the frame 1. In the single path region 31, long threading guide members 5 and 6 are disposed in parallel to each other with a predetermined clearance, which is greater than the thickness of a later-described threading member 20, in the direction perpendicular to a paper web, thereby forming a threading-member traveling path 40 through which the threading member 20 can travel. At locations where the guide support brackets 4 are disposed, the two parallel threading guide members 5 and 6 are fixed to the tip ends of both legs of each guide support bracket 4, which has a C-shaped cross section. The base portion of each guide support bracket 4 is fixed to the lower end of the vertical portion 2a of the bracket 2. In this way, the threading guide members 5 and 6 are attached to the frame 1 such that they are properly separated from the inner surface of the frame 1 in the widthwise direction of the paper web. Drive rollers (not shown) are disposed along the threading paths at a pitch smaller than the length of the threading member 20, and are driven by unillustrated drive means. The threading guide 20, which is nipped by the paired drive rollers and is fed thereby, travels through the threading-member traveling path 40 while being guided. As shown in FIG. 11, the threading member 20 is a flexible strip having a predetermined length. A paper-web bonding portion 20a projects sidewise from the forward end portion of the threading member 20. The threading member 20 is inserted between the upper and lower threading guides 5 and 6 and is forced to travel. A plurality of guide pins 21 and 22 are disposed in line at opposite transverse sides of the threading member 20 such that they project from the top and bottom surfaces of the threading member 20. The array of guide pins 21 and the array of guide pins 22 are disposed on opposite sides of the threading guide members 5 and 6. Accordingly, during traveling, the threading member 20 is guided by the threading guide members 5 and 6, and is prevented, by the array of guide pins 21 and the array of guide pins 22, from moving in the widthwise direction of the paper web W with respect to the threading guide members 5 and 6. The threading member 20 is inserted such that the paper-web bonding portion 20a projects from the threading member 20 in the direction opposite to the bracket 2. The forward end portion of each side edge of the paper web W is bonded to the paper-web bonding portion 20a. Lower and upper threading guide members 7 and 8 of the branch region 32 follow the threading guide members 5 and 6 of the single path region 31. Among the threading guide members 7 and 8, the lower threading guide member 7 extends straight even after passing through the branching point and becomes a threading guide member 7a, while the upper guide member 8 bends at a predetermined angle at the branching point so as to branch obliquely and then becomes a threading guide member 8a. The threading guide member 8a bends again so as to be parallel to the threading guide member 7a. There is further disposed a branch threading guide member having a V-shaped end portion and composed of threading guide members 9 and 10, which are parallel to the threading guide members 7a and 8a, respectively. As a result, the threading-member traveling path 40 branches into a straight threading-member traveling path 41 and a slanted threading-member traveling path 42. At the branching point in the branch region 32 is disposed a threading path switching apparatus A. The threading path switching apparatus A has four shifters 11a, 11b, 12a, and 12b, each formed of a quadrilateral plate. These shifters 11a, 11b, 12a, and 12b are disposed in two parallel planes that are perpendicular to the paper web W and parallel to the threading-member traveling path 40. In detail, the shifters 11a and 12a are disposed in one of the parallel planes such that they face each other with a predetermined clearance and are located on the upper and lower sides of the threading-member traveling path 40. The shifters 11b and 12b are disposed in the other parallel plane such that they face each other with a predetermined clearance and are located on the upper and lower sides of the threading-member traveling path 40. As will be described later, the shifters 11a and 11b respectively face the shifters 12a and 12b with predetermined vertical clearances therebetween through which the guide pins 21 and 22 pass. The plane in which the shifters 11a and 12a are located and the plane in which the shifters 11b and 12b are located are determined such that they are located on either side of the guide members 7, 7a, 8, 8a, 9 and 10 so as to correspond to the positions of the array of guide pins 21 and the array of guide pins 22 of the threading member 20. The shifters 11a and 11b respectively have guide edges 13a and 13b, which respectively face the shifters 12a and 12b. These guide edges 13a and 13b are substantially parallel to the threading guide member 7. The shifters 12a and 12b respectively have guide edges 14a and 14b, which respectively face the shifters 11a and 11b. These guide edges 14a and 14b are substantially parallel to that portion of the threading guide member 8a, which extends obliquely. The length of the shifters 11a and 11b in the direction of the threading path is determined such that their guide edges 13a and 13b become longer than the horizontal component of the clearance of the threading-member traveling path 42 at the branching point in the branching region 32; i.e., such that they have a sufficient length to close the threading path 42. The length of the shifters 12a and 12b in the direction of the threading path is determined such that the vertical component of the slanted guide edges 14a and 14b becomes larger than the clearance of the straight threading-member traveling path 41; i.e., such that they have a sufficient length to close the straight threading path 41 at the branching point in the branch region 32. When the shifters 11a and 11b are positioned to close the slanted threading-member traveling path 42, the guide edges 13a and 13b of the shifters 11a and 11b engage with the array of guide pins 21 and 22. In this state, the guide edges 13a and 13b are spaced from the guide surfaces of the threading guide members 8 and 9 to such an extent as to allow the threading member 20 to pass through the straight threading-member traveling path 41. When the shifters 12a and 12b are positioned to close the straight threading-member traveling path 41, the guide edges 14a and 14b of the shifters 12a and 12b engage with the arrays of guide pins 21 and 22. In this state, the guide edges 14a and 14b are raised from the guide surface of the threading guide member 10 to such an extent as to allow the threading member 20 to pass through the slanted threading-member traveling path 42. The guide edges 13a and 13b of the shifters 11a and 11b each have a slanted or arcuate shape in an upstream introduction zone or over the entire length, so that the distance between the guide edges 13a and 13b and the threading-member traveling path 40 increases toward the upstream side. As a result, when the tip ends of the arrays of guide pins 21 and 22 of the threading member 20 contact the guide edges 13a and 13b, they are smoothly guided by the guide edges 13a and 13b. In the above-described first embodiment, the shifters 11a and 12a guide the array of guide pins 22, while the shifters 11b and 12b guide the array of guide pins 21. However, these shifters 11a, 11b, 12a, and 12b may be modified such that they guide the threading member 20 itself. In this case as well, the above-described structure is employed. However, the shifters 11a, 11b, 12a, and 12b are designed such that when the shifters 11a and 11b are positioned to close the slanted threading-member traveling path 42, the guide edges 13a and 13b of the shifters 11a and 11b become substantially flush with the guide surfaces of the threading guide members 8 and 9, while the guide edges 14a and 14b of the shifters 12a and 12b become substantially flush with the guide surface of the threading guide member 10. More specifically, the guide edges 13a and 13b of the shifters 11a and 11b each have a slanted or arcuate shape in an upstream introduction zone or over the entire length, so that the distance between the guide edges 13a and 13b and the threading-member traveling path 40 increases toward the upstream side. This ensures that the threading member 20 is smoothly introduced to the branching point while being prevented from engaging with the upstream introduction ends of the guide edges 13a and 13b. Moreover, in order to ensure smooth introduction of the threading member 20 into the straight threading-member traveling path 41, the downstream exit ends of the guide edges 13a and 13b are flush with the guide surface of the threading member 9 or slightly project therefrom. In a first modification (A) shown in FIG. 4, the shifters 11a and 12a and the shifters 11b and 12b are respectively disposed at positions that are inwardly offset in the widthwise direction from the positions corresponding to the arrays of guide pins 21 and 22. In the branch region 32, through depressions are formed on both side surfaces of the guide members 7, 7a, 8, 8a, 9, and 10 so as to allow the shifters 11a and 12a and the shifters 11b and 12b to enter the depressions in the vertical direction. In a second modification (A) shown in FIG. 5, the shifters 11a and 12a and the shifters 11b and 12b are disposed in a same manner as in the first embodiment. However, a single array of guide pins 21 are embedded into the threading member 20 at the substantially center position in the widthwise direction. Guide grooves 19, into which the upper and lower ends of the guide pins 21 are inserted, are formed in the opposite guide surfaces of all the threading guide members such that the guide grooves 19 are located at the substantially center position in the widthwise direction. Each of the threading guide members may be composed of two parallel members that are assembled such that a clearance serving as the guide groove 19 is formed therebetween. The widthwise movement of the paper web W relative to the threading guide members 5 and 6 is prevented by the engagement between the array of guide pins 21 and the guide grooves 19. Next, a description will be given of a threading path switching apparatus B used in a branching apparatus for a threading guide of a rotary press according to a second embodiment of the present invention. It is to be noted that in the description directions (upward, downward, rightward, and leftward) denote directions in FIG. 6, and that in each drawing the direction of a threading-member traveling path after a branching point represents an exemplary direction. As shown in FIGS. 6-8, two paired shifters are disposed on the upward side and the downward side so as to face each other. This structure reduces the number of components and the size of the apparatus as compared to the threading path switching apparatus A. That is, in the branch region 32, the paired shifters 11 and 12 facing each other are disposed at a predetermined position in the widthwise direction of the guide members 7, 7a, 8, 8a, 9, and 10. As shown in FIG. 7, through-clearances into which the shifters 11 and 12 move are formed in the guide members 7, 7a, 8, 8a, 9, and 10 at a widthwise position corresponding to the position of the shifters 11 and 12. The guide edges 13 and 14 of the shifters 11 and 12 faces the opposite surfaces of the threading member 20. Each of the threading guide members may be composed of two parallel members that are assembled such that a through-clearances is formed therebetween. The guide edge 13 of the shifter 11 and the guide edge 14 of the shifter 12 have shapes identical to those of the shifters according to the first embodiment. The array of guide pins 21 and the array of guide pins 22 are disposed on the opposite sides of all the threading guide members. Accordingly, during traveling, the threading member 20 is prevented, by the array of guide pins 21 and the array of guide pins 22, from moving in the widthwise direction of the paper web W with respect to the threading guide members 5 and 6. In a modification shown in FIG. 8, like the modification shown in FIG. 5, a single array of guide pins 21 are embedded into the threading member 20 at the substantially center position in the widthwise direction. Longitudinally extending guide grooves into which the upper and lower ends of the guide pins 21 are inserted are formed in the opposite guide surfaces of all the threading guide members. Each of the threading guide members is composed of two separated parallel members so as to form a clearance serving as the guide groove. The shifters 11 and 12 also enter the guide grooves. The guide edge 13 of the shifter 11 and the guide edge 14 of the shifter 12 have shapes identical to those of the shifters used in the first embodiment. At the branching point, the shifters 11 and 12 guide the array of guide pins 21 and the widthwise movement of the paper web W relative to all the threading guide members is prevented by the engagement between the array of guide pins 21 and the guide grooves. In the above-described first and second embodiments (see FIGS. 2 and 7), at a position corresponding to the branching point in the branch region 32, an air cylinder 15 for vertical movement is disposed between the vertical portion 2aof the bracket 2 and the inner surface of the frame 1 and is attached to the vertical portion 2a. The air cylinder 15 is controlled by an unillustrated outside controller. To lower end of a downwardly projecting piston rod 15a of the air cylinder 15, the edge portion of one side of a shifter mounting bracket 16 having an L-shaped cross section is attached via an adjustable mechanism. This makes it possible to adjust the position of the shifter mounting bracket 16 in the operation direction. The other side of the shifter mounting bracket 16 forms a vertical portion 16a having a flat surface separated from the vertical portion 2a of the bracket 2. The end portions of the shifters 11a and 11b opposite the guide edges 13a and 13b (or the end portion of the shifter 11 opposite the guide edge 13) are attached to the vertical portion 16a of the shifter mounting bracket 16 via parallel mounting pins 17. The end portions of the shifters 12a and 12b opposite the guide edges 14a and 14b (or the end portion of the shifter 12 opposite the guide edge 14) are attached to the vertical portion 16a of the shifter mounting bracket 16 via parallel mounting pins 18. The reference positions of the shifters 11a, 11b, 12a, and 12b (or the shifters 11 and 12) are adjusted by the adjusting mechanism. When the piston rod 15a is projected as a result of operation of the air cylinder 15, the shifter mounting bracket 16, i.e., the shifters 11a, 11b, 12a, and 12b (or the shifters 11 and 12) are located at the lowered position. When the piston rod 15a is retracted as a result of operation of the air cylinder 15, the shifter mounting bracket 16, i.e., the shifters 11a, 11b, 12a, and 12b (or shifters 11 and 12) are located at the elevated position. As shown in FIG. 2A, when the shifter mounting bracket 16 is located at the lowered position, the guide edges 14a and 14b of the shifters 12a and 12b (the guide edge 14 of the shifter 12) are separated away from the threading-member traveling path 40, while the guide edges 13a and 13b of the shifters 11a and 11b (the guide edge 13 of the shifter 11) are located at a guide pin engagement/guidance position or a threading member engagement/guidance position at which the slanted threading-member traveling path 42 is closed at the branching point and the threading guides 8 and 9 are connected. As a result, the threading-member traveling path 40 communicates with the straight threading-member traveling path 41. As shown in FIG. 2B, when the shifter mounting bracket 16 is located at the elevated position, the guide edges 13a and 13b of the shifters 11a and 11b (the guide edge 13 of the shifter 11) are separated away from the threading-member traveling path 40, while the guide edges 14a and 14b of the shifters 12a and 12b (the guide edge 14 of the shifter 12) are located at a guide pin engagement/guidance position or a threading member engagement/guidance position at which the straight threading-member traveling path 41 is closed at the branching point and the threading-member traveling path 40 is connected to the slanted threading-member traveling path 42. Next, a description will be given of a branching apparatus for a threading guide of a rotary press according to a third embodiment of the present invention. It is to be noted that in the description directions (upward, downward, rightward, and leftward) denote directions in FIG. 10, and that in each drawing the direction of a threading-member traveling path after a branching point represents an exemplary direction. The mutual mounting structure among the frame 1 of the rotary press, the bracket 2, the threading guide member, and the threading path switching apparatus C is the substantially the same as that of the first embodiment. In the third embodiment shown in FIG. 10, there is provided a complex branch region 33 which is connected to the single path region 31 of the threading-member traveling path and in which the traveling-member traveling path is branched into three paths. In the complex branch region 33, there are provided lower and upper straight threading guide members 7 and 8 that follow the threading guide members of the single path region 31. Among the threading guide members 7 and 8, the lower threading guide member 7 extends straight even after passing through a first branching point and becomes a threading guide member 7a, while the upper guide member 8 bends at a predetermined angle at the first branching point so as to branch obliquely and then becomes a threading guide member 8a. The threading guide member 8a bends again so as to be parallel to the threading guide member 7a. There is further disposed a branch threading guide member having a V-shaped end portion and composed of guide members 9 and 10, which are parallel to the threading guide members 7a and 8a, respectively. As a result, the threading-member traveling path 40 branches into a straight threading-member traveling path 41 and a slanted threading-member traveling path 42. Moreover, among the lower threading guide member 7a and the upper threading guide member 9 that extend straight at the first branching point, the lower threading guide member 7a extends straight even after passing through a second branching point and becomes a threading guide member 7b, while the upper guide member 9 bends at a predetermined angle at the second branching point at the same angle as that of the threading guide member 8. The upper guide member 9 thus branches obliquely and then becomes a threading guide member 9a. The threading guide member 9a bends again so as to be parallel to the threading guide member 7b. There is further disposed a branch threading guide member having a V-shaped end portion and composed of guide members 7c and 9b, which are parallel to the threading guide members 7b and 9a, respectively. As a result, the threading-member traveling path 40 branches into a straight threading-member traveling path 41 and a slanted threading-member traveling path 43. A threading path switching apparatus C is disposed along the first and second branching points in the complex branching region 33. The threading path switching apparatus C has a pair of shifters 51 each formed of a quadrilateral plate, and another pair of shifters 52 each formed of a trapezoidal plate. These shifters 51 and 52 are disposed in two parallel planes that are perpendicular to the paper web W and parallel to the threading-member traveling path 41, such that they are located on the opposite sides of the threading guide members 7, 7a, 7b, 7c, 8, 8a, 9, 9a, 9b, and 10 so as to sandwich them in the widthwise direction of the paper web. In detail, the shifters 51 and 52 are disposed in each of the parallel planes such that they face each other with a predetermined clearance and are located on the upper and lower sides of the threading-member traveling path 41. As will be described later, the shifter 52 is offset from the shifter 51 by a predetermined amount in the direction of the threading path 41. As in the first and second embodiments of the present invention, the guide edge 53 (the lower edge in FIG. 10) of the shifter 51 and the guide edge 54 (the upper slanted edge) of the shifter 52 may be located such that they face the arrays of guide pins 21 and 22 of the threading member 20 or such that they face opposite surfaces of the threading member 20 itself. The guide edge 53 of the shifter 51 is substantially parallel to the threading guide members 7 and 7a, while the guide edge 54 of the shifter 52, which faces the shifter 51, is substantially parallel to the slanted threading guide members 8a and 9a. The length of the shifter 51 in the direction of the threading path is determined such that the guide edge 53 has a sufficient length so as to simultaneously close the slanted threading-member traveling path 42 at the first branching point and the slanted threading-member traveling path 43 at the second branching point. The length of the shifter 52 in the direction of the threading path is determined such that the guide edge 54 has a sufficient length so as to simultaneously close the straight threading-member traveling path 41 at the first and second branching points. The positions of the guide edges for the case where the guide edges of the shifters face the arrays of guide pins and for the case where the shifters face the opposite surfaces of the threading member 20 are identical to those in the first embodiment. When the shifter 51 is positioned to close the slanted threading-member traveling paths 42 and 43, the guide edge 53 of the shifter 51 becomes substantially flat with the guide surfaces of the threading guide members 8, 9, and 7c. When the shifter 52 is positioned to close the straight threading-member traveling path 41, the guide edge 54 of the shifter 52 becomes substantially flat with the guide surfaces of the threading guide members 10 and 9b. In detail, the guide edge 53 of the shifter 51 has a slanted or arcuate shape in an upstream introduction zone or over the entire length, so that the distance between the guide edge 53 and the threading-member traveling path 41 increases toward the upstream side. This ensures smooth introduction of the threading member 20 into the branching point without causing engagement between the upstream introduction end of the guide edge 53 and the traveling threading member 20. Further, in order to ensure smooth introduction of the threading member 20 into the straight threading-member traveling path 41, the downstream exit end of the guide edge 53 is flush with the guide surfaces of the threading members 9 and 7c or slightly projects therefrom. In the above-described embodiment, two pairs of shifters are used. However, as in the second embodiment of the present invention, a single pair of shifters, i.e., a shifter 51 formed of a quadrilateral plate and a shifter 52 formed of a trapezoidal plate may be used. The paired shifters 51 and 52 facing each other are disposed at a predetermined position in the widthwise direction of the guide members 7, 7a, 7b, 7c, 8, 8a, 9, 9a, 9b, and 10. Through clearances into which the shifters 51 and 52 move are formed in the guide members 7, 7a, 7b, 7c, 8, 8a, 9, 9a, 9b, and 10 at a widthwise position corresponding to the position of the shifters 51 and 52. This structure is substantially the same as that disclosed in FIGS. 6, 7, and 8. In the complex branch region 33, a double-acting air cylinder 56 is attached to the inner surface of the frame of the rotary press via a proper bracket 55. The double-acting air cylinder 56 is controlled by an unillustrated outside controller. To the lower end of a horizontally projecting piston rod 56a of the double-acting air cylinder 56, a shifter mounting bracket 57 is attached via an adjustable mechanism, which makes it possible to adjust the position of the shifter mounting bracket 57 in the operation direction. The shifter mounting bracket 57 has a sufficient length in the direction of the threading path to cover the first and second branching points of the complex branch region 33 and is parallel to the inner surface of the frame. The based end portions (left end portions in the example shown in FIG. 10) of the shifters 51 are attached to the shifter mounting bracket 57 via parallel mounting pins 17, while the end portions of the shifters 52 opposite the guide edges 54 are attached to the shifter mounting bracket 57 via parallel mounting pins 18. The reference positions of the shifters 51 and 52 are adjusted by the adjusting mechanism. When the piston rod 56a is retracted as a result of operation of the double-acting air cylinder 56, the shifter mounting bracket 57, i.e., the shifters 51 and 52 are located at the leftward end position in FIG. 10. When the piston rod 56a is located at an intermediate position as a result of operation of the double-acting air cylinder 56, the shifter mounting bracket 57, i.e., the shifters 51 and 52 are located at the intermediate position. When the piston rod 56a is projected as a result of operation of the double-acting air cylinder 56, the shifter mounting bracket 57, i.e., the shifters 51 and 52 are located at rightward end position in FIG. 10. The mutual positional relationship between shifters 51 and 52 and the positional relationship with respect to the threading-member traveling path 41 are determined as follows. As shown in FIG. 10, when the shifter mounting bracket 57 is moved to the leftward end position, the guide edges 53 of the shifters 51 are positioned at positions located away from the first and second branching points, while the guide edges 54 of the shifters 52 are located at a guide pin engagement/guidance position or a threading member engagement/guidance position at which the straight threading-member traveling path 41 is closed at the first branching point and the threading guides 7 and 10 are connected. As a result, the threading-member traveling path 40 communicates with the slanted threading-member traveling path 42. When the shifter mounting bracket 57 is moved to the intermediate position, the guide edges 53 of the shifters 51 are located at a guide pin engagement/guidance position or a threading member engagement/guidance position at which only the slanted threading-member traveling path 42 is closed and the threading guides 8 and 9 are connected. At this time, the guide edges 54 of the shifters 52 are located at a guide pin engagement/guidance position or a threading member engagement/guidance position at which the straight threading-member traveling path 41 is closed at the second branching point and the threading guides 7a and 9b are connected. As a result, the threading-member traveling path 40 communicates with the slanted threading-member traveling path 43. When the shifter mounting bracket 57 is located at the rightward end position, the guide edges 54 of the shifters 52 are positioned at position located away from the second branching point as well as the first branching point. The guide edges 53 of the shifter 51 are located at a guide pin engagement/guidance position or a threading member engagement/guidance position at which the slanted threading-member traveling path 42 and the slanted threading-member traveling path 43 are simultaneously closed at the first and second branching points and the threading guide members 8, 9 and 7c are connected. As a result, the threading-member traveling path 41 is maintained opened over the entire region of the branching apparatus section of the threading guide of the rotary press. In the above-described embodiments, instead of the air cylinders 15 and 56, a hydraulic cylinder or an electromagnetic drive apparatus may be used as means for vertically moving the shifter mounting bracket 16 or as means for horizontally moving the shifter mounting bracket 57. Next, a description will be given of the operations of the branching apparatuses for the threading guide of the rotary press. For the first embodiment, the operation of the branching apparatus shown in FIGS. 1-4 will be described. In the threading path from the upstream paper feed section to the downstream folding section, the threading member 20 having a paper-web bonding portion 20a, to which the forward end of each transverse edge of the paper web W is attached, is caused to travel along a predetermined threading-member traveling path while being guided by the threading guide. As a result, the paper web W is threaded along a predetermined threading path. At the branching point of the threading path, the threading member 20 travels toward the threading-member traveling path selected by the threading path switching apparatus, so that the paper web W is also threaded toward a predetermined threading path selected accordingly. In detail, the threading member 20 travels along the threading-member traveling path 40, while being guided by the threading guide members 5 and 6 in the single path region 31, and then reaches the branch region 32 of the threading guide in which the threading member 20 is guided by the threading guide members 7 and 8 to the branching point. When it is desired to allow the threading member 20 to travel in straight from the threading-member traveling path 40 to the threading-member traveling path 41, the air cylinder 15 is operated such that the shifter mounting bracket 16, i.e., the shifters 11a, 11b, 12a, and 12b are moved to the lowered position via the piston rod 15a. With this operation, the guide edges 14a and 14b of the shifters 12a and 12b are separated away from the threading-member traveling path 40, while the guide edges 13a and 13b of the shifters 11a and 11b are located at a guide pin engagement/guidance position or a threading member engagement/guidance position at which the threading-member traveling path 42 is closed at the branching point and the threading guide members 8 and 9 are connected. As a result, the threading member 20 travels into the threading-member traveling path 41 formed by the guide members 9 and 7a in a state in which the upper ends of the guide pins 21 and 22 of the threading member 20 are guided by the guide edges 13a and 13b of the shifters 11a and 11b, or in a state in which the threading member 20 itself is guided by the guide edges 13a and 13b of the shifters 11a and 11b and the threading guide members 7 and 7a. When it is desired to allow the threading member 20 to travel from the threading-member traveling path 40 to the slanted threading-member traveling path 42, the air cylinder 15 is operated such that the shifter mounting bracket 16, i.e., the shifters 11a, 11b, 12a, and 12b are moved to the elevated position via the piston rod 15a. With this operation, the guide edges 13a and 13b of the shifters 11a and 11b are separated away from the threading-member traveling path 40, while the guide edges 14a and 14b of the shifters 12a and 12b are located at a guide pin engagement/guidance position or a threading member engagement/guidance position at which the straight threading-member traveling path 41 is closed at the branching point and the threading guide members 7 and 10 are connected. As a result, the threading member 20 travels into the threading-member traveling path 42 formed by the guide members 8a and 10 in a state in which the lower ends of the guide pins 21 and 22 of the threading member 20 are guided by the guide edges 14a and 14b of the shifters 12a and 12b, or in a state in which the threading member 20 itself is guided by the guide edges 14a and 14b of the shifters 12a and 12b and the threading guide members 7 and 10. The operation of the branching apparatus according to the second embodiment (which has a single pair of shifters) is substantially the same as that of the branching apparatus according to the first embodiment. At the branching point, the guide edges 13 and 14 of the shifters 11 and 12 close the corresponding threading-member traveling path or are located at the guide pin engagement/guidance position or threading member engagement/guidance position for connecting the threading guide members that form a threading-member traveling path to which the threading member is to be guided. As a result, the arrays of guide pins 21 and 22 or the threading member 20 itself is allowed to travel to a predetermined threading-member traveling path selected by the shifters 11 and 12. In the third embodiment shown in FIG. 10, at each of the plurality of branching points, the threading member 20 is caused to travel to a predetermined threading-member traveling path selected by the threading path switching apparatus. Consequently, the paper web W is threaded along a predetermined threading path selected accordingly. In the complex branch region 33, the threading member 20 is caused to travel to one of the three threading-member traveling paths 41, 42 and 43 by operating the threading path switching apparatus C as follows. When the shifter mounting bracket 57, i.e., the shifters 51 and 52 are located at the rightward end position by the double-acting air cylinder 56 via the piston rod 56a, the guide edges 54 of the shifters 52 are positioned at position located away from the second branching point as well as the first branching point, while the guide edges 53 of the shifter 51 are located at a guide pin engagement/guidance position or a threading member engagement/guidance position at which the slanted threading-member traveling paths 42 and 43 are closed at the first and second branching points and the threading guide members 8, 9 and 7c are connected. As a result, the threading member 20 travels into the threading-member traveling path 41 formed by the guide members 7b and 7c in a state in which the upper ends of the guide pins 21 and 22 of the threading member 20 are guided by the guide edges 53 of the shifters 51, or in a state in which the threading member 20 itself is guided by the guide edges 53 of the shifters 51 and the threading guide members 7, 7a and 7b. When the shifter mounting bracket 57, i.e., the shifters 51 and 52 are located at the intermediate position by the double air cylinder 56 via the piston rod 56a, the guide edges 53 of the shifters 51 are located at a guide pin engagement/guidance position or a threading member engagement/guidance position at which the slanted threading-member traveling path 42 is closed at the first branching point and the threading guide members 8 and 9 are connected. Also, the guide edges 53 of the shifters 51 open the slanted threading-member traveling path 43 at the second branching point. The guide edges 54 of the shifters 52 are located at a guide pin engagement/guidance position or a threading member engagement/guidance position at which the straight threading-member traveling path 41 is closed at the second branching point and the threading guide members 7a and 9b are connected. As a result, the threading-member traveling path 40 communicates with the slanted threading-member path 43. Accordingly, the threading member 20 travels into the threading-member traveling path 43 formed by the guide members 9b and 9b in a state in which the upper ends of the guide pins 21 and 22 of the threading member 20 are guided by the guide edges 53 of the shifters 51 and the lower ends of the guide pins 21 and 22 are guided by the guide edges 54 of the shifters 52, or in a state in which the threading member 20 itself is guided by the guide edges 53 of the shifters 51 and the threading guide members 7 and 7a and also guided by the threading guide member 9a and the guide edge 54 of the shifter 52. When the shifter mounting bracket 57, i.e., the shifters 51 and 52 are located at the leftward end position by the double air cylinder 56 via the piston rod 56a, the guide edges 53 of the shifters 51 are positioned at position located away from the second branching point as well as the first branching point, while the guide edges 54 of the shifter 52 are located at a guide pin engagement/guidance position or a threading member engagement/guidance position at which the straight threading-member traveling path 41 is closed at the first branching point and the threading guide members 7 and 10 are connected, so that the threading-member traveling path 40 communicates with the slanted threading-member traveling path 42. As a result, the threading member 20 travels into the threading-member traveling path 42 formed by the guide members 8a and 10 in a state in which the lower ends of the guide pins 21 and 22 of the threading member 20 are guided by the guide edges 54 of the shifters 52, or in a state in which the threading member 20 itself is guided by the guide edges 54 of the shifters 52 and the threading guide members 8a. In the above-described branching apparatuses for threading according to the respective embodiments, a single threading-member traveling path is formed on the upstream side and is then branched into a plurality of threading-member traveling paths on the downstream side, and the threading member travels from the upstream single threading-member traveling path to the downstream plurality of threading-member traveling paths. However, the branching apparatuses for threading according to the above-described embodiments can be applied to the type in which a plurality of threading-member traveling paths are provided on the upstream side and they are merged into a single threading-member traveling path on the downstream side, and in which a paper-web bonding member is bonded to the edge portion of a threading strip serving as the threading member is threaded over the entire area of the threading path from the upstream side to the downstream side and is caused to travel for performing threading. That is, the above-described type can be used in the case where the threading member is caused to travel along selected threading-member traveling path from the upstream side to the lower stream side for forming a threading path. It is easily understood that in this case as well, the guide edges of the shifters are formed such that they do not hinder smooth travel of the threading member, including the guide pins, from the downstream side to the upstream side. Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein.	A branching apparatus is provided in a paper-web threading apparatus of a rotary press in which, in order to thread a paper web into a threading path of the rotary press, threading guides are disposed at side portions of the threading path to extend therealong, thereby forming a threading-member traveling path through which a threading member can travel. The branching apparatus includes a branch threading guide in which a plurality of downstream threading-member traveling paths are formed such that they communicate with a single upstream threading-member traveling path via respective branching points, shifters disposed in the vicinity of the branch threading guide and having guide edges which operates at the branching points of the branch threading guide so as to guide the threading member to a selected downstream threading-member traveling path while closing the unselected downstream threading-member traveling path, and a drive for moving the shifter so as to selectively open and close the downstream threading-member traveling paths. It is possible to allow smooth traveling of the threading member. In addition, the branching apparatus can be simplified and be made compact.	1
RELATED APPLICATION This application is a continuation-in-part of copending application Ser. No. 07/859,158, filed Mar. 27, 1992. FIELD OF THE INVENTION The present invention relates to systems used in the practice of dentistry, and more particularly, to systems for cutting, excavating and etching teeth or associated tooth structure by means of finely divided abrasive materials carried in a fluid stream. BACKGROUND OF THE INVENTION The use of abrasive-laden fluid streams to treat teeth has long been known. For example, U.S. Pat. No. 2,661,537 to Angell describes equipment for treating teeth with a relatively high-pressure stream laden with abrasive particles. While the use of such equipment has gained a significant degree of success in connection with the cleaning of teeth, there has heretofore been an overall lack of success in the dental industry with respect to the use of such equipment for cutting, excavating or etching teeth. Applicant has found that this lack of success can be attributed to several heretofore unrecognized disadvantages associated with equipment of the type described in Angell. For example, cutting or etching of teeth with gas/abrasive streams frequently requires a source of fluid at pressures of at least about 120 psig. Unfortunately, however, compressed air in the range of about 60 to 80 psig is generally the highest pressure available in dental operatories. In order to overcome this limitation, the Angell patent describes the use cylinders containing CO 2 gas at a pressure of about 800 psig as a source of pressurized fluid. Applicant has found that there are numerous disadvantages associated with the use of pressurized gas in this form. For example, applicant has found that one important factor in successfully achieving cutting, etching and/or excavating tooth enamel is proper regulation and control of the pressure at which such operations are carried out. Such precise control and regulation is difficult to achieve in the system described in Angel. One reason for this difficulty is the very large pressure differentials between the pressure needed to operate the system (e.g. 100 to 120 psig) and the pressure at which the gas is delivered (800 psig). In particular, the accuracy of pressure regulation equipment is frequently inversely proportional to the pressure differential across the regulating device. Thus, the precision of the regulated pressure frequently decreases as the pressure differential increases. Another disadvantage of the equipment described in Angell is that it is capable of providing only two pressure levels for the fluid utilized to operate the system. Applicant has found that this is another reason for the lack of success achieved by prior devices. It is highly desirable to operate at more than two distinct and different pressure levels because of the multiplicity of dental procedures performed by the dentist. The equipment described in Angell, however, is capable of supplying fluid at only two distinct pressure levels. As a result, the required precision in operating the dental instrument is deficient. Another disadvantage arises on account of the provision for the supply of gas in compressed form in cylinders. In view of the considerable volume of gas being used, cylinder replacement becomes a severe inconvenience. Thus, applicant has found that the use of equipment as described in Angell is a disadvantage in treatment operations involving the use of abrasive-laden fluid streams. The prior art use of abrasive-laden fluid streams for treatment of teeth has also suffered from the disadvantageous of having significant excess and/or post-use abrasive particles in the area of the mouth during operation. The presence of such abrasive particles is not only uncomfortable to the patient being treated, but it may also constitute a hinderance to the dentist conducting the operation. This disadvantage is particularly relevant for cutting and abrading of teeth since the relatively high pressures required for such operations sometimes result in a cloud or mist of excess or post-use abrasive particles which make it difficult for the dentist to see the area being treated. This difficulty has heretofore not been fully overcome. OBJECTS AND SUMMARY OF THE INVENTION In view of the deficiencies of the prior art, it is thus an object of the present invention to provide improved dental systems which utilize pressurized fluid streams containing abrasive particles for effectively and efficiently abrading, etching and cutting teeth or associated tooth structure. As used herein, by associated tooth structure is meant fillings, composites, facings, crowns, caps, amalgam and the like. It is a further object of the invention to bring together the components needed to produce a novel and effective dental tool capable of overcoming past deficiencies of systems using abrasive-laden fluid streams. It is a further object of this invention to provide dental apparatus for treating teeth via an abrasive-laden stream of high pressure fluid, such as air, in which the disadvantages associated with the presence of excess abrasive particles are eliminated or substantially reduced. It is a further object of the present invention to provide dental apparatus which utilize pressurized fluid streams containing abrasive particles wherein the apparatus is capable of operating selectively at two or more precisely controlled pressure levels. Yet another object of the invention is the use of a common suction system for purging the equipment of excess abrasive particles and collection of post-use abrasive particles. The common suction system may include connection means for connection to the office suction and waste collection systems pre-existing within the dental office. Advantageously, suction may be provided by a water venturi which draws off abrasive particles and debris into the water stream passing through the venturi. These and other objects are satisfied by the preferred system aspects of the present invention. The present system is directed to the treatment of teeth by means of abrasive particles carried by a gas stream. According to one preferred embodiment, the system comprises, in combination with a source of air: means for increasing the pressure of said air to an initial pressure; a pressure selection means for selectively providing said air at least a first or a second pressure, each of said first and second pressures being less than about said initial pressure; an abrasive delivery means for combining the abrasive particles with said air at one of said first or second pressures to provide an abrasive-laden air stream; and nozzle means for delivering said abrasive-laden air stream to the teeth to be treated. According to another preferred embodiment, the system comprises, in combination with a source of air at an initial pressure: a pressure selection means for selectively providing said fluid at least a first, a second, or a third pressure, each of said first, second and third pressures being less than about said initial pressure; an abrasive delivery means for combining finely divided abrasive particles with said air at one of said pressures to provide an abrasive-laden air stream; and nozzle means for delivering said abrasive-laden air stream to the teeth to be treated. Another aspect of the present invention, which is preferably used in combination with the treatment system aspects hereof, is directed to evacuation systems especially well adapted for removing excess and/or post-use abrasive particles from in and around the area of the mouth during dental operations- Such systems preferably comprise a vacuum conduit having a first, relatively large diameter outer conduit member and a second, relatively small diameter inner conduit member, wherein said first and second members are moveable in a longitudinal direction with respect to one another. In this configuration, the outer conduit member may be placed adjacent to the chin, cheek, or lips of the patient receiving treatment while the inner conduit member may be selectively positioned within the mouth of the patient being treated. The evacuation system may include integral vacuum means and may optionally and additionally include means for connection to the dental office suction system for the evacuation of particulate debris and abrasive. Another aspect of the present invention, which is optionally but not necessarily used in combination with one or more of the other aspects hereof, is directed to a system for controlling the pressure of the abrasive/air mixture leaving the delivery nozzle means. Such control systems preferably include pneumatic control means, such as fluid discharge ports on the handle of the dental apparatus for activating or deactivating the flow of pressurized fluid therein. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing the elements of one embodiment of the delivery system of the present invention. FIG. 2 is a block diagram showing one embodiment of the pressure selector means 11 illustrated in FIG. 1. FIG. 3 is a block diagram showing one embodiment of one aspect of the pressure selector means shown in FIG. 2. FIG. 4 is a block diagram showing a second embodiment of one aspect of the pressure selecting means illustrated in FIG. 2. FIGS. 5 and 5A are block diagrams showing a preferred embodiment of the treatment systems of the present invention, including the control systems therefor. FIG. 5B is a view showing the abrasive delivery system with attendant controls. FIG. 6 is a block diagram illustrating one embodiment of the treatment system of the present invention in combination with one embodiment of the evacuation system of the present invention. FIG. 6A is a block diagram illustrating a second embodiment of an evacuation system of the present invention. FIG. 7 is a cross-sectional view of a two--stage evacuation nozzle according to one embodiment of the present invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The present invention is directed generally to dental treatment systems and dental components adapted for use in connection with such systems. As the term is used herein, "treatment" refers to any operation for altering the physical condition of the teeth or gums by impacting same with an abrasive-laden fluid stream. As the term is used herein, "teeth" refers to teeth in their natural state as well as teeth that have been filled or otherwise modified by earlier dental treatment. FIG. 1 is a schematic representation of a system embodying the present invention and utilizing a stream of operating fluid delivered through a conduit 100. The illustrated system comprises the following components: fluid supply means 101 connected to the conduit 100 for providing a stream of said fluid in a second conduit 102 at an initial pressure; pressure selection means 103 connected to the stream within conduit 102 for selectively providing a fluid stream within a conduit 104 at least at a first or second pressure, each of said pressures being less than about the initial pressure of the stream in conduit 102; means 105 connected to conduit 104 for combining said fluid stream within conduit 104 with abrasive particles to produce an abrasive-laden fluid stream within a delivery conduit 106; and handpiece means 107 connected to conduit 106 for discharging or delivering a stream or fluid jet 108 against the tooth or tooth structure of the patient to be treated. Preferably, pressure selection means 103 also comprises means for selectively providing a substantially abrasive-free stream of pressurized fluid to said handpiece means 107 by means of a conduit 109. Thus, preferred systems of the type disclosed in FIG. 1 may alternatively and selectively be operated in a first mode wherein the abrasive-laden stream is provided to handpiece means 107 or a second mode wherein a substantially abrasive-free stream is provided to the handpiece. Applicant has discovered that highly desirable and beneficial characteristics are associated with dental treatment systems having such a pressure selection means. For example, the systems of the present invention are designed to provide abrasive-laden fluid streams for cutting of teeth, such as is required in preparation for filling of cavities with amalgam or the like. As the cavity is expanded by the abrasive-laden stream, the abrasive particles may sometimes tend to settle or collect in the cavity and produce a layer of abrasive particles in the cavity. The presence of this layer, in turn, may reduce the effectiveness of the cutting operation under certain conditions. Accordingly, it is a highly desirable aspect of the present invention that the dental treatment system of the present type be selectively operable between an abrasive-laden mode and an abrasive-free mode so that such layer can be readily removed by blowing with a stream of air. It has been found that the use of abrasive-free air acts to dry the tooth undergoing treatment which allows for better cutting and abrading efficiency. As described above, an important consideration in achieving successful operation of dental treatment systems is the degree to which the system permits precise control and regulation of the fluid operating pressure. This consideration is important because the regulation of fluid pressure helps to control the action of the abrasive-laden stream on the tooth. However, the rate at which abrasive particles are delivered to the fluid stream is also frequently an important variable in achieving successful system operation. That is, fluid pressure and abrasive delivery rate each have an influence upon the cutting or abrading characteristics of the fluid stream. Moreover, it has been discovered that a specific correspondence or relationship between fluid pressure and abrasive delivery rate should exist in order to achieve results which are consistently commercially acceptable. Improper matching of these two operating parameters can preclude effective operation of the dental system. The pressure selection means 103 of the present invention preferably includes means for providing a control signal 110 for controlling the rate at which abrasive delivery means 105 provides abrasive to the fluid stream within conduit 104. The present system preferably operates such that the control signal 110 be modulated according to the pressure selected. In this way, the systems of the present invention are capable of producing an abrasive delivery rate which is precisely matched to the pressure selected and hence to the desired operation. In general, it can be said that at relatively low pressures, abrasive powder tends to accumulate at relatively low points in the system, whereas by moving air at a faster rate, higher pressures above a given pressure, depending upon the design of the systems, will be effective to move all of the powder available. The present system optionally includes means 112 (illustrated in FIGS. 6 and 7) in juxtaposition to the mouth of the person being treated for removing excess and/or post-use abrasive particles from in and around the mouth. The present systems also optionally may include or are associated with a dental laser of the type described, for example, in U.S. Pat. Nos. 5,055,048, issued Oct. 8, 1991 and 4,940,411, issued Jul. 10, 1990. According to such preferred embodiments, the present treatment systems further include means for directing a beam of laser light toward the teeth of the patient being treated. In this way, the dentist or other dental professional may utilize the present system to alternatively and selectively treat the teeth of the patient with an abrasive-laden fluid stream or a dental laser. The components of the present systems may be housed, either together or separately, in one or more suitable housings. In certain embodiments, however, it is preferred that the dental treatment systems be incorporated into a stand-alone, portable unit which can be transported to numerous locations and connected to the appropriate local power supply and fluid source. In such embodiments, it is preferred that the components are housed together on or in a relatively compact housing. A. Fluid Supply Means The nature and character of the fluid supply means 101 of the present invention may vary widely, depending upon numerous factors, such as the particular operating fluid being used. The material which comprises the fluid stream supplied through conduit 100 may also vary widely within the scope hereof, depending upon such factors as cost and availability, and the use of a wide variety of materials are within the scope hereof. It is preferred, however, that the fluid of the present invention comprise a gaseous material, and even more preferably air. It will be also appreciated that the construction of fluid supply means 101 may vary depending upon factors such as the pressure of the operating fluid being used. For example, it is contemplated that in certain embodiments the fluid source within conduit 100 is provided at a pressure which is sufficiently high to operate the dental systems of the present invention without further compression. In such embodiments, the fluid supply means 101 may simply comprise, for example, a supply conduit for transporting the fluid from its source to the pressure selection means 103. As mentioned above, however, the preferred fluid, i.e., air, is generally only available in dental operatories at pressures limited to about 60 to at most about 90 psig. This source of operating fluid is preferred because of its ready availability and low cost. While air at such pressures may be acceptable for numerous dental applications, applicant has found that such pressures are insufficient to perform the preferred etching and cutting operations for which the present system is especially well adapted. In particular, applicant has found that successful cutting, abrading and etching operations require a source of gas at a pressure of from about 80 to 200 psig. According to preferred embodiments, therefore, the preferred fluid source comprises operatory air at a pressure of less than about 80 to about 90 psig and the fluid supply means 101 comprises means for increasing the pressure of the operatory air to greater than about 80 psig, and even more preferably to a pressure of from about 80 to about 200 psig. The pressure increasing means of the present invention may comprise any one of several well known structures for increasing the pressure of the selected fluid medium. The selection of any particular pressure increasing means will depend upon numerous factors such as flow rate, pressure differentials, sealing methods, methods of lubrication, power consumption, serviceability and cost. It is contemplated, therefore, that the pressure increasing means may take numerous forms within the scope hereof. For embodiments in which the operating fluid is a gas, it is contemplated that the pressure increasing means may comprise, for example: fans, both axial and centrifugal; compressors, both axial and centrifugal; rotary blowers; reciprocating compressors, both single stage and two stage; and ejectors. For embodiments in which the preferred fluid is air, the preferred means for increasing the fluid pressure comprises an air pressure intensifier of the type sold, for example, by Haskel Incorporated of Burbank, Calif. 97502, under Model No. MAA-2.5. The fluid supply means 101 according to preferred embodiments also includes means for storing the pressurized fluid. The fluid supply means 101 also preferably includes means for stabilizing the pressure of fluid stream within conduit 102. According to simple and effective embodiments of the present invention, the means for storing the pressurized fluid also acts as the means for stabilizing the pressure of fluid stream 102. For example, the air exiting the pressure increasing means in the preferred embodiment is transported to a fluid supply tank adapted to maintain a reservoir of the pressurized air. This fluid supply tank not only provides a high pressure reservoir, it also serves to buffer or dampen the pressure spikes or fluctuations frequently encountered with dental operatory air. For preferred embodiments, especially those in which the present system is a substantially portable system, the fluid supply tank comprises an air storage bottle capable of maintaining at least one cubic feet of air at a pressure of about 250 psi. In this way, fluctuations in the pressure of the fluid exiting the fluid supply means is minimized. B. Means For Selectively Reducing the Fluid Pressure With reference to FIG. 2, an important aspect of the present dental treatment systems resides in the provision of means 103 for selectively reducing the pressure of the fluid stream within conduit 102. In particular, means 103 makes the operating fluid selectively available at least at two and preferably at least three discrete pressure levels, said discrete pressure levels each preferably being less than about the initial pressure level of the fluid provided by the fluid supply means 101 but substantially above atmospheric. While it is contemplated that numerous structures may be adaptable for use as the pressure selection means, it is preferred that the pressure selection means 103 comprise inlet manifold means 114 connected to said fluid supply means 101 for providing at least first and second flow paths 116 and 117 for the operating fluid. Each of said first and second flow paths 116 and 117 preferably include pressure regulating means 118 and 119 for precisely regulating the pressure in a downstream portion of the flow path. Unless the context clearly indicates otherwise, the term "downstream" refers to that region of the flow path downstream of the pressure regulating means and "upstream" refers to that region of the flow path upstream of the pressure regulating means. Each flow path is thus divided by its respective pressure regulating means into a high pressure upstream portion and a low pressure downstream portion. According to highly preferred embodiments, the flow paths are connected in parallel configuration. That is, the manifold means 114 is configured such that the upstream pressure in said first flow path 116 is substantially equivalent to about the upstream pressure in said second flow path 117. The preferred selective pressure reduction means 103 is readily adaptable and well suited for selectively providing the operating fluid at three or more pressure levels, with each of said pressure levels being less than about the initial pressure of the fluid provided by the fluid supply means. Applicant has found that such an embodiment is especially beneficial for the provision of a dental treatment system well adapted for use in each of the following three dental operations: cutting, etching and abrading. Thus, it is highly preferred that the inlet manifold means 114 include means for providing a first flow path, a second flow path and a third flow path, each of said flow paths being connected in a parallel configuration. The use of such a configuration according to the preferred aspects of the present invention permits the utilization of three distinct, precisely controllable operating pressures for the dental instrument. Applicant has found that this is an important feature of such preferred embodiments since it allows flexibility of use while simultaneously preserving precise control and regulation of the necessary fluid stream. For use in applications where the cleaning of the teeth is contemplated, a fourth parallel flow path may be provided with pressure in the fourth flow path being regulated to a level which is lower than the other pressure levels. With particular reference now to FIG. 3, the selective pressure reduction means 103 of the present invention also preferably includes selective valve means 120 and 121 in a portion, and preferably a downstream portion, of each of the flow paths 116 and 117 for selectively blocking and unblocking the flow of fluid through the respective flow paths. It is contemplated that numerous valves of the type known and available in the industry are adaptable for use for this purpose, and all such valves are within the scope of the present invention. According to preferred embodiments hereof, as disclosed more fully hereinafter, the valves of the present invention are preferably high pressure solenoid operated valves of a type well known in the art. Each of the flow paths also preferably includes in a downstream portion thereof, means 124 and 125 for preventing back flow of said pressurized fluid. The back-flow prevention means are preferably located in a portion of said flow path which is downstream of said valve means 120 and 121. In a typical arrangement, means 124 and 125 each comprise a check valve in the flow path immediately downstream of valve means 120 and 121, respectively, each such check valve being of any type and construction well known in the art. Additionally, a filters 122 for removing unwanted debris or particles from the fluid should be included in a downstream portion of the flow paths. The filters are of particular importance in the prevention of the migration of abrasive back into the solenoid operated valves and the check valves, thus avoiding equipment failure. Another aspect of the invention illustrated in FIG. 1 involves the supply of gas at a pressure close to but somewhat below the lower of any of the operating pressures established by the selective pressure reduction means, directly to the inlet of the abrasive particle delivery system. For reasons which will become apparent in the following, it is of importance that at start up, prior to the selection of any particular operating pressure level, the abrasive particle delivery system be immediately activated by the supply of regulated air under pressure. For this purpose, in systems where operatory air at pressures of about 80 psig is available in conduit 100, a branch conduit 123 delivers regulated air directly from line 100 to air/abrasive unit 105. In order to regulate the pressure of this air supply, a pressure regulator 126 is provided which maintains the pressure in line 123 at a preset limit, for example, between about 60 and about 80 psig. The selective pressure reducing means 103 preferably comprises control means 127 for providing a control signal (indicated by dashed lines) to the valve means 120 and 121, thereby selectively opening and/or closing the valve means. In the preferred embodiments in which the valve means is a solenoid operated valve, the control means comprises a solenoid for each of said valves and an electrically operated circuit for opening and closing the solenoid valve, as more fully described hereinafter. The pressure reducing means 103 also preferably includes an exit manifold means 128 connected to flow paths 116 and 117. The function of the exit manifold means 28 is to provide a source of fluid 104 at the selected pressure to the air/abrasive means 105. Thus, the exit manifold means 128 preferably comprises a conduit connected between a downstream portion of each of said flow paths 116 and 117 and said abrasive delivery means. The selective pressure reduction means 103 also preferably includes pressure relief means for relieving fluid pressure in excess of that selected for the particular operation. Important functions of the pressure relief means are to ensure that pressure of the fluid is immediately adjusted to the selected pressure and, in addition, that it does not unexpectedly and unwantedly rise, because of a malfunction in the system, substantially beyond that pressure selected by the dentist or other dental professional. Control means is also preferably provided for selectively controlling the relief means such that the activating pressure of the relief means corresponds to or is slightly greater than the maximum pressure in the pressure range selected by the dentists. As the term is used herein, "activating pressure" refers to the pressure at which the pressure relief system relieves the build-up of pressure in the system. It will be appreciated that the provision of such pressure relief means according to the present invention constitutes an important aspect of certain embodiments hereof. For example, the relief means provides a way of immediately establishing a selected pressure and gives the health professional a confidence that the desired pressure level is reliably at the pressure selected. In addition, it would be undesirable and potentially detrimental to the patient if the operating pressure in the dental treatment system was suddenly and unintentionally raised above the selected operating pressure. If such were to occur, the rate of flow and the pressure of the jet stream leaving the dental handpiece would unexpectedly increase beyond the desired pressure range. This unexpected and undesired increase may not only reduce the efficacy of the desired dental treatment, it may also, depending upon the extent of the pressure increase, cause harm and injury to the patient being treated. Accordingly, it is important and highly desirable that the dental treatment systems of the present invention include mechanisms for ensuring that desired pressure is reliably established and that such an unexpected pressure increase does not occur. An preferred configuration of the downstream portion of pressure selection means 103 is illustrated in FIG. 4. According to the embodiment of FIG. 4 and also indicated in FIG. 1, the system includes means for providing a substantially abrasive-free stream 109 to handpiece 107. Applicant has found that the provision of such means, particularly when such means is operable separately and independently of remaining portions of the pressure selection means, is highly desirable, as described hereinbefore. Accordingly, with reference to FIG. 4, the substantially abrasive-free delivery means comprises, for example, conduit 129 leading from a downstream portion of flow path 116 and selective valve means 131 in the flow path for selectively blocking and unblocking the flow of fluid therethrough. The conduit 129 also contains a pressure regulator 130 to regulate the pressure of the abrasive-free air flowing to the nozzle. Control means 127 is connected to valve means 131 for selectively and independently operating the valve means 131. A check valve 132 and filter 133 are preferably located downstream of valve means 131 for preventing the back flow of fluid or contaminants and abrasives therethrough. As further illustrated in FIG. 4, the pressure relief means comprises a pressure relief means associated with each selectable pressure range. For example, relief means 134 and 135 are connected to exit manifold means 128 for relieving fluid pressure in the exit manifold to the extent such pressure is in excess of the fluid pressure selected. The exit manifold 128 will, depending upon the operating pressure selected, be subject to at least a relatively high pressure and a relatively low pressure. When the relatively low pressure is selected, no difficulty is presented. On the other hand, the presence of the low pressure relief means in fluid communication with the exit manifold would, in the absence of the pressure relief blocking means of the present invention, prevent operation in the relatively high pressure mode. Accordingly, each pressure relief means 134 and 135 is preferably connected to control means 127 such that the relief means is operative when the pressure range of its associated flow path is selected and inoperative when a higher pressure range is selected. Thus, each pressure relief means 134 and 135 preferably includes a valve means connected to control means 127 for selectively blocking and unblocking flow of pressurized fluid to the respective pressure relief mechanism, depending upon the pressure selected for operating the system. In operation, therefore, the valve means for each relief mechanism is activated to the unblocked position when the operating pressure range associated with that relief means is selected. Conversely, the valve means remains in the unactivated, blocked position when all higher pressure ranges are selected, thus assuring that the desired pressure will be immediately and reliably available to the operator. C. Control System, Abrasive Delivery and Pressure Relief Means With reference now to FIGS. 5 and 5A, a preferred embodiment showing details of the selective pressure reducing means, including control systems and pressure relief means thereof is disclosed. As fully explained hereinafter, the system illustrated provides for selective delivery of air and abrasive at three discrete pressure levels or a supply of air free of abrasive. Turning first to FIG. 5, the illustrated system includes a source of fluid, preferably air, at a pressure of about 60 to about 90 psig and air supply means 101 which includes means for increasing the pressure of the air so as to supply a stream of air through line 102 at a pressure of from about 80 to about 200 psig. A valve 138 operated by a solenoid 139 is positioned upstream from the supply means 101. Valve 138 is a normally closed valve (hereinafter an NC valve) which is actuated to the opened position by the solenoid 139 upon the closing of a main switch 140. The opening of valve 138 allows the flow of air to a pressure regulator 141 in conduit 123 and to supply means 101 and conduit 102, a check valve 142 to an inlet manifold means comprising the common manifold conduit 143 which corresponds to manifold 20 in FIG. 2 and manifold branch conduits 144 through 146 and the connections therefor. Each branch conduit 144 through 146 comprises a flow path for the pressurized air and includes therein pressure regulators 148 through 150 for regulating the pressure in a downstream portion of the respective conduit. Although the downstream pressures in conduits 144 through 146 may vary depending upon the particular operations contemplated, it is preferred that they be regulated to a pressure within a high pressure range, a mid pressure range and a low pressure range, respectively. More particularly, a high pressure range of about 160 to 180 psig is preferred for cutting and excavating of tooth enamel, a mid pressure range of about 120 to 140 psig is preferred for etching tooth enamel and a low pressure range of about 80 to 100 psig is preferred for cleaning teeth. In addition, manifold branch line 152, in which a pressure regulator 153 is located, provides for delivery of a supply of regulated air free of abrasives and a manifold branch line 154 in which a regulator 155 is located, provides for delivery of air free of abrasive to the teeth or for the evacuation of abrasive from the system downstream from the abrasive unit, as will be explained hereinafter. Immediately downstream of the pressure regulators 148 through 150 and 153 are NC valves 148A through 150A operated by solenoids 148B through 150B, respectively. Downstream of the valves 148A through 150A are found check valves 156 through 158, respectively. Exit manifold means comprising manifold conduit 160 and pressure gauge 161 is connected to and in fluid communication with a downstream portion of each of the conduits 144 through 146. Also connected to and in fluid communication with manifold conduit 160 is a pressure relief means comprising three relief valves 162 through 164 protected by NC valves 166 through 168 operated by solenoids 169 through 171, respectively. Exit manifold conduit 160 leads from each of conduits 144 through 146 to abrasive delivery means 105 for producing a stream of abrasive-laden gas at the desired pressure to a handpiece 107 through a conduit 172. From the foregoing, it can be seen that upon closure of main switch 140, NC valve 138 is opened. This allows operatory air to flow through pressure regulator 141 directly to manifold 160 to pressurize the air abrasive delivery system which is preferably of the kind illustrated and claimed in U.S. Pat. No. 4,708,534 and as generally disclosed in FIG. 5B. The system may further be provided with a switch 101A located in conjunction with the air reservoir within fluid supply means 101. Switch 101A prevents operation of the system, except when there is an adequate pressure level within the reservoir. With particular reference to FIG. 5B, the preferred form of abrasive delivery system 105 will be described briefly. The system includes a sealed lower chamber 175 mounted on a base 176 and an abrasive powder supply vessel 177 which is bolted or otherwise fastened to the top of chamber 175. Located within chamber 175 is an upwardly open cylindrical particle feed receptacle 178 which is mounted on a vibratory device 179, as particularly described in the aforesaid U.S. Pat. No. 4,708,534. Cylindrical feed receptacle 178 is provided on its inner surface with a helical feed groove 180, the lower end of which communicates with the bottom of the cylinder and the top of which is in communication with a feed tube 181 which delivers the particulate material through a section of resilient, flexible tubing 182 to an exit tube 183 which passes through the wall of vessel 175. Joined to tube 183 is a second section of resilient flexible tubing 184 which is in turn connected to a duct 172 which leads to handpiece 107, as is illustrated in FIG. 5. Powder supply receptacle 177 is adapted to receive and contain a supply of particulate abrasive matter, generally indicated by the reference character P and to supply the same in a uniform manner to the bottom of cylindrical feed device 178 through a feed tube 186 in a manner more particularly described in U.S. Pat. No. 4,708,534. In order to bring the powder delivery system up to a pressure at which it is primed for operation, air under pressure, for example, of about 80 psi, is delivered to chamber 175 by way of a connection 187 which is connected to line 160 which is pressurized upon closure of valve 138 when main control switch 140 is closed. A branch conduit 188 also supplies air at the same pressure to the powder supply chamber 177 by means of a connection 189 which communicates with the interior of the supply chamber 177. Vibratory device 179 is an electrically operated device which is preferably activated off handpiece 107 by means to be described hereinafter. In general, the rate of vibratory feed is controlled by way of a preset adjustable control device 190 mounted on the equipment control panel in a convenient location. Device 190 may be set manually by the operator to a desired vibratory rate or optionally may be a pressure responsive device which automatically adjusts through connections to switch 191 so that an appropriate rate is provided for the operating pressure level as selected on switch 191. The abrasive delivery system is also preferably provided with a normally closed valve 192 which is preferably a pinch valve of the kind illustrated more particularly in FIG. 10 of the aforesaid U.S. Pat. No. 4,708,534. Pinch valve 192 is controlled by a solenoid 193 either directly or through a fluid pressure device. The solenoid 193 is preferably energized upon closure of a switch activated off the handpiece to maintain pinch valve 192 in the open position whenever vibrator 179 is in operation. In summary, when the main switch 140 is closed, chambers 175 and 177 are immediately pressurized at the low end of the operating pressure range so that the abrasive delivery system is readied for the delivery of a particulate-laden air stream through resilient tube 184 to conduit 185 when desired by the operator. Upon activation of the vibrator and opening of pinch valve 192 by the control circuitry, described hereinafter, particulate material advances upwardly within spiral groove 180 through duct 181 where it enters resilient, flexible tubing 182 and exit tube 183, where it exits container 175 and passes through tube 184 to join conduit 185. It will be appreciated by those skilled in the art that it may be desirable to use different abrasives and/or different particle size abrasives for different dental operations. For example, it may be desirable to utilize abrasive particles having one set of characteristics for a first dental operation and a second set of characteristics for a second dental operation. While it is possible to manually change the type of abrasive being used, it is preferred that the abrasive delivery system of the present invention include means for selectively providing either a first abrasive particle or a second abrasive particle for mixing with the fluid stream. One apparatus capable of achieving this result is disclosed in U.S. Pat. No. 2,661,537 to Angell, which is incorporated herein by reference. As explained above, closure of main switch 140 also allows the operatory air to be delivered to the air pressure intensifier 101 which preferably increases the pressure of the available air to be supplied to a level of approximately 200 psig. Air at this pressure is then delivered through conduit 143. FIG. 5 further illustrates the system provided for controlling the selective pressure reduction means and for selective delivery to the handpiece of pure air under pressure or a pressurized air and abrasive mix as required. The control system preferably involves the use of separate pressure selector switch 191 and additionally includes controls on the dental handpiece 107, operation of the selective pressure reduction means being described first. The pressure selector switch 191 is located in any convenient position on the control panel or optionally and/or additionally may be incorporated in a foot actuated switching device of a type well known in the art. As is illustrated in FIG. 5, when switch 191 is in the open position (as shown), the NC valves 148A through 150A remain closed and the flow of operating fluid through any one of valves 148A through 150A is thus blocked. With switch 191 in any one of the closed positions, the appropriate solenoid 148B through 150B is energized, thereby allowing fluid to flow through the appropriate conduit 144 through 146. As seen in FIGS. 5 and 5A, conduit 144 through 146 deliver air to manifold 160 at a pressure established by the respective pressure regulator 148 through 150. Since the pressure in conduit 160 can be within any one of the three above described pressure ranges, the pressure relief means includes first, second and third relief valves for relieving pressure in excess of said first, second and third pressure ranges, respectively. The first relief valve 162 is calibrated with an activation pressure which corresponds to or is slightly greater than the maximum operating pressure in the downstream portion of flow path 144, while relief valves 163 and 164 are calibrated to have activation pressures which correspond to or are slightly greater than the maximum operating pressure in the downstream portions of flow paths 145 and 146, respectively. When a control signal is transmitted to solenoid 148 to open valve 148A, solenoid 169 is activated by the same control signal, thereby opening blocking valve means 166. However, blocking valves 167 and 168 remain closed, thereby isolating the relief valves 163 and 164 from the operating fluid when the system is operated in the high pressure mode. It will be understood that similar operation occurs in the mid- or low-pressure modes. As indicated above, means are provided to deliver air at relatively low pressure as established by pressure regulator 153 through the conduit 152. This conduit bypasses the abrasive supply unit 105, delivering a regulated supply of air at a relatively low pressure directly to the inlet of the handpiece 107 to provide the operator with a stream of abrasive-free air useful for drying the region of the tooth as is frequently desired. For this purpose, normally closed valve 151A in line 152 is opened by energization of a solenoid 151B which is preferably controlled by a pressure operated switch activated by closure of one of a group of control ports on handpiece 107, as described below. Line 152 is further provided with a filter 152A and check valve 159 to isolate the valve components from the air and abrasive mixture. In one condition of operation of the system, as will be described subsequently, the air delivered through line 152 may also be used to create a vacuum downstream from the abrasive delivery system so as to effect removal of the mixture of abrasive and/or debris from the interior of the handpiece. As indicated just above, a plurality of control ports provided on the handpiece 107 enable certain functions of the system of the present invention. According to the preferred embodiment of the invention, shown in FIG. 5, the handpiece is preferably provided with four fluid control ports 194 through 197, each of which is conveniently located to be closed by a finger of the operator. Ports 194 through 197 are located in series-circuit relationship with a relatively low pressure supply of air, supplied for example, through branching conduit 154 and regulated by pressure regulator 155 (FIG. 5). The ports 194 through 197 control three normally open diaphragm operated pressure switches 198, 199 and 201 and one diaphragm operated latching switch 200, each of which receives pressurized air from conduit 154. So long as handpiece ports 194 through 197 are uncovered, air at a relatively low pressure passes through the diaphragm chamber of each of the switches 198 through 201 and exits through the ports. However, upon closure of a selected one of ports 194, 195 and 197, one or more of the normally open switches 198, 199 and 201 will be closed on account of the increase in pressure to which the diaphragm in the switch is subjected. In the case of latching switch 200, momentary closure of port 196 is effective to latch switch 200 in the closed position if initially opened and to return it to the open position if closed. As illustrated in FIG. 5A, port 194 is a lamp activation port which communicates with the diaphragm chamber of switch 198 which, when closed, energizes a circuit which lights a lamp 202 (which may include a fiber optic device) which casts a beam of light through an opening in the distal end of handpiece 107 for the purpose of illuminating the area of a tooth or related tooth structure being worked on by the operator. So long as port 194 is closed, the lamp 202 remains illuminated. Port 195 is a light and air activation port which is in communication with normally open lamp switch 198 through a conduit 204 and 205 and in communication with the diaphragm chamber of normally open diaphragm operated switch 198 by means of conduits 204 and 205 so as to effect closure of switches 198 and 199 when port 195 is closed, thus turning on lamp 202 and activating solenoid 212 so as to close valve 213 to deliver air free of abrasive from conduit 152 to the handpiece. Port 196 is a powder evacuation activator port which is in communication with latching switch 200 by means of conduit 206 and may also be in communication with the light switch 199 by means of a branch conduit 207. Upon closure of port 196, the light will be turned on and switch 200 closed to energize a solenoid 191A which activates switch 191 to turn on vacuum 221, as described hereinafter in reference of FIG. 6. Port 197 is the port for activation of the powder delivery system and is in communication with normally open diaphragm operated switch 201 via lines 208 and 211. Closure of switch 201 by placing a finger over port 197 energizes solenoid 193 to open pinch valve 192 and turns on vibrator 179. Simultaneously, solenoid 212 is energized to close normally opened purge valve 213. The relatively high pressure air abrasive mixture is directed through conduit 172 and out through nozzle 107A. Since the pressure of the air and abrasive mix is high relative to the pressure of the air in line 152, check valve 159 blocks flow of pure air through line 152. However, as soon as the user removes his finger from port 197 to terminate the delivery of the air and abrasive mix, pure air again flows past the check valve 159. Opening of the switch deenergizes solenoid 212 to open pinch valve 214 so that air flows out through purge line 214. Because there is a small orifice in the tip of handpiece 107 relative to the cross-section of the purge line, the rush of air creates a vacuum. As indicated in FIGS. 5 and 5A, the various branch circuits are provided with check valves to insure that closure of a particular port activates only through switches which are required to perform the functions indicated. In addition, filters 152A and 217 provided in lines 152 and 160 insure that abrasive does not enter the manifold system. Although the use of the above-described fluid ports constitute a preferred method of control, it should be understood that electrically operated switches positioned on the handpiece and utilizing a low voltage power source could be employed without departing from the scope of the invention. D. Dental Handpiece Means It will be appreciated by those skilled in the art that the particular form of the handpiece 107 may vary widely, depending upon factors such as cost and portability. In general, it is preferred that the handpiece be adapted to be carried and manipulated by the dentist or other dental professional. For this reason, handpiece 107 is generally formed in the shape of an elongate cylinder connected to the abrasive/fluid delivery means 105 by way of the conduit 172 (see FIG. 5), which conduit should be flexible for ease of manipulation. A central bore in the handpiece transports the abrasive-laden fluid to a nozzle means 107A disposed at the distal end thereof. In addition, the handpiece is provided with a fiber optic channel to accommodate lamp 202 and a fiber optic device which terminates at the distal end of portion 107A for the purpose of directing light in the area of impact of the abrasive particles. The nozzle means 107A may be, for example, frusto-conically shaped, thereby providing a cross-sectional flow area which reduces gradually from that of about the central bore to a relatively small opening in the end of the nozzle. This reduction in flow area results in a concomitant increase in fluid velocity, thereby producing a stream or jet of abrasive-laden fluid 108 which is effective for cutting, etching or cleaning teeth or related tooth structure, depending upon the operating pressure of the system. The particular configuration and construction of such handpieces is generally well known, and all such constructions are within the scope of the present invention. One such handpiece is shown in U.S. Pat. No. 2,696,049, which is incorporated herein by reference. As illustrated in the '049 patent, the nozzle portion of the delivery means is preferably readily removably attached to the handpiece. Such removability is beneficial in several respects. First, it will be appreciated that the flow of high velocity abrasives through the nozzle 107A of the present dental treatment systems will tend to cause wear and abrasion of the internal channel of the nozzle. This could, in turn, reduce the efficacy of the system. Accordingly, the provision of a removable nozzle permits replacement of the nozzle as needed to maintain the efficacy of the system. In addition, applicant contemplates that the nozzle 107A may, in certain embodiments, be comprised of a relatively inexpensive material, such as plastic. In such embodiments, it is expected that the nozzle would be discarded after each use. The provision of such a low cost, inexpensive replaceable nozzle has the obvious advantage of reducing a likelihood of the spread of infectious disease from one patient to the next. It is contemplated that the removability of the present nozzle may be achieved by providing the nozzle with a threaded portion, as disclosed in the '049 patent, or other means, such as providing a bayonet type attachment between the nozzle and the remainder of the handle portion. In addition, the entire handpiece should be separable from conduit 172 and from its associated control lines to permit autoclaving. According to another preferred embodiment of the present invention, the portion of the nozzle which comes in contact with the abrasive-laden fluid stream may be formed of a hard, abrasion-resistant material, such as carbide. Thus, the nozzle itself can be formed of such carbide material, or formed of less expensive materials which are lined with carbide or similar abrasion-resistant materials. E. System for Evacuating Abrasive Material In its preferred form, the dental treatment system of the present invention includes the provision of means for effectively and efficiently evacuating excess abrasive particles from the area of the mouth after treatment. As noted, above, the failure of prior art dental treatment systems to effectively deal with the continued removal of abrasive particles from the mouth has contributed to the lack of acceptance of the systems. With particular reference to FIGS. 6, 6A and 7, the invention preferably includes a two-piece vacuum nozzle means, generally indicated at 220, adapted to be placed in the mouth of a patient and a means for creating a vacuum within the nozzle means so as to draw away the abrasive particles and debris. According to FIG. 7, nozzle means 220 preferably includes an outer tubular housing section 222 and an inner tubular section 223 co-axially mounted within section 222 by means such as a support plate 224. Preferably, inner tubular member 223 has an outwardly flared portion 225 which is intended to be positioned adjacent to the region of the patient's mouth during treatment. A plurality of spaced apart openings 226 are located in a plate 224. Preferably, inner tubular conduit section 223 is frictionally fitted within a sleeve or collar 227 which is joined to support plate 224. The frictionally interfitting portions provide a means permitting longitudinal adjustment of inner tubular member relative to the outer section 222 so as to permit movement of the flared portion 225 to accommodate patients having different sized mouths and/or to allow for adjustment to bring the flare portion into different areas of the mouth. Evacuator nozzle 220 is connected to a flexible hose 230 which is coupled onto the end of the outer tubular housing section 222. Preferably, the cross-sectional area of the openings 226 and the cross-sectional area of the inner tubular section 223 should roughly equal the cross-sectional area of tube 230 so as to avoid an unwanted choking down of the air drawn from the patient's mouth. As indicated in FIG. 6, conduit 230 preferably is connected to the vacuum means 221 which comprises a conventional electric motor operated vacuum system which, in one embodiment, includes a rigid, removable disposable container 232 within which the used abrasive and debris is collected. A valve 233 within conduit 230 blocks flow through the conduit. As indicated in FIG. 6, valve 233 is manually operated. In addition, pressure selector switch 191 operates electric motor for vacuum 221 so as to draw air from the nozzle 107A and the patient's mouth area as soon as a particular pressure is selected, thereby avoiding the possibility of excess abrasive escaping to the atmosphere. With the system described, substantially all abrasive delivered to the patient's mouth, as well as the debris created by the cleaning, abrading and cutting operations, is captured by the vacuum system and delivered to the rigid disposable container 232 which is preferably readily sealable for separate handling and disposable at a medical disposal waste site, if necessary. FIG. 6 also illustrates purge line 214 which, as explained above, is opened so as to convey away abrasive from the system downstream from the air abrasive means 105 when the operator removes his finger from handpiece port 197. Desirably, a filter 233 filters out any abrasive drawn through conduits 230 or 214 by vacuum means 221. FIG. 6A illustrates an alternative form of means for creating a vacuum. According to FIG. 6A, the vacuum means comprises a water venturi shown at 221. Both conduits 214 and 230 are connected to the throat of the venturi. The flow of water through the venturi creates a subatmospheric pressure in the throat drawing excess abrasive from evacuator nozzle 220 and purge line 214. With reference back to FIG. 6, the system may also comprise a branch passage 234 which has a connector 235 which permits connection to the standard suction system 236 available in most dental offices. The operation of the illustrative embodiment of the invention will now be briefly summarized with particular reference to FIGS. 5A and 5B. When main power switch 140 is turned on, solenoid 139 effects the opening of valve 138 delivering air under pressure of between about 60 and 90 psig to the pressure intensifier 101. Simultaneously, a regulated supply of air is delivered through conduits 123 and 160 to the air abrasive delivery unit priming this unit by pressurizing chamber 175 and powder supply 177. The operator chooses the particular operating pressure for delivery of the air-abrasive mixture through use of selector switch 191 which may be conveniently located on the instrument panel or, alternatively, through a four-position foot activated switch, not shown, having four actuating positions which are connected in parallel with the contacts of switch 191. At this point, the device is fully primed for operation which is achieved through selective control by closure of an appropriate port on the dental handpiece 107. If the operator wishes to only illuminate the tooth or related tooth structure to be worked on, he closes finger port 194 which effects closure of the lamp circuit to light lamp 202. If the operator then wishes to direct a jet of drying air to the tooth or tooth structure, finger port 195 is closed which effects energization of the lamp circuit and a closure of purge valve 213. Closure of port 196 latches switch 200 in the closed position which activates the vacuum system of FIG. 6. Finally, when the operator is ready to apply the air abrasive mix to the tooth or tooth region, the covers port 197 which energizes solenoid 193 to open pinch valve 192, turns on vibrator 179 and closes normally open purge valve 213. When port 197 uncovered, the flow of air and abrasives stops, the purge valve 213 is opened and air through line 152 purges portions of the system downstream of abrasive unit 105 of abrasive materials. In the illustrative embodiment, the vacuum system is activated whenever pressure selection switch 191 is turned on with the result that abrasive particles and tooth debris are drawn from the region of the patient's mouth whenever an air/abrasive mixture is delivered by the handpiece as well as when drying air alone is delivered and when the operator is merely inspecting the area being treated. Through the unique combination of pressure relief valves 162 through 164 and blocking valves 166 through 168, the pressure chosen for use in the treatment of teeth may be readily and rapidly changed by use of selector switch 191. When switching from a higher to a lower operating pressure, the change occurs immediately, enabling the operator to work confidently and without delay. Still further, switch over from cutting and abrading to the use of air only for cleaning and drying the tooth region being worked on or the use of the light only can be readily and rapidly accomplished by controls conveniently located on the dental handpiece.	A system of treating teeth or associated tooth structure using an abrasive-laden fluid stream provides fluid at high pressure to a manifold with selectively operable valves to deliver fluid at a selected pressure to a mixer for the fluid and abrasive and delivery to a device for application to a patient's mouth. Priming air at low pressure pressurizes the mixer. An alternate air path bypasses the mixer. A selective control delivers a stream of fluid or fluid and abrasive to the tooth or tooth structure. Upon termination of treatment, pure air is diverted through a purge line to purge the system of abrasive. A vacuum is selectively operable to remove abrasive and debris from the mouth during and after the abrasive treatment. The abrasive delivery device includes a hand-held nozzle having ports operable by the fingers for control. The vacuum includes a rigid, disposable collection chamber for sterile disposal of the abrasive and debris and has a common filter for the purge circuit and for removal of abrasive and debris from the mouth. Connection to the dental office suction system or a water powered venturi provides suction. Pressure regulation and relief insures instantaneous change from one pressure level to the next.	1
TECHNICAL FIELD OF THE INVENTION This invention relates to aligning pipe sections for welding, and particularly to welding using copper back-up shoes. BACKGROUND OF THE INVENTION In assembling a pipeline, it is common to align the abutting ends of two pipe sections together with a line-up clamp positioned within the pipe sections at the joint to be welded. Once aligned, a more effective weld can be performed by use of back-up shoes, particularly made of copper, at the joint to be welded which engage the inside surface of both pipe sections at the joint. Devices such as shown in U.S. Pat. No. 5,356,067 to Leduc, U.S. Pat. No. 5,110,031 to Rinaldi, U.S. Pat. No. 4,556,162 to Gwin, et. al., and U.S. Pat. No. 3,937,382 to Cunningham, et. al., disclose devices with back-up shoes and discuss the advantages thereof. Smaller diameter pipe cannot accept the typical line-up pipe clamp as discussed in the patents noted above. For smaller pipe, a technique has been developed, as disclosed in U.S. Pat. No. 5,090,608 to Jones, for providing a line-up clamp using expandable disks, made of polyurethane, to clamp against the inside surfaces of the pipe sections to be welded. In smaller pipe, no effective back-up shoe mechanism has yet been developed. SUMMARY OF THE INVENTION A line-up clamp is provided for clamping first and second pipe sections in alignment for welding. The line-up clamp includes a guide assembly with a fluid cylinder mounted to the guide assembly and having an elongate rod movable between a first position and a second position relative the fluid cylinder. The elongate rod has a distal end. A first plurality of expandable disks are concentric with a first portion of the elongate rod while a second plurality of expandable disks are concentric with a second portion of the elongate rod. A center member is concentric with the elongate rod between the first and second plurality of expandable disks. An end member is rigidly mounted on the elongate rod at the distal end thereof. The elongate rod in the first position expands the first and second plurality of disks between the end member, center member and guide assembly to clamp the first and second pipe sections in alignment for welding. At least one back-up shoe is mounted at the center member. The back-up shoe moves against the inside surfaces of the aligned pipe sections when the elongate rod is in the first position and moves to a release position spaced from the interior surfaces when the elongate rod is in the second position. In accordance with another aspect of the present invention, a first tube is slidable along the first portion of the elongate rod and concentric therewith. A first actuator body is operationally coupled to the first tube at an end of the first tube proximate the center member. The back-up shoe is pivotally mounted to the actuator body. In accordance with another aspect of the present invention, the first tube is operably coupled to the first actuator body by a coil spring. In accordance with another aspect of the present invention, a second tube is slidable along the second portion of the elongate rod and concentric therewith and a second actuator body is operationally coupled to the second tube at an end of the second tube proximate the center member. A second back-up shoe is pivotally mounted to the second actuator body. Movement of the elongate rod to the first position causes the first and second actuator bodies to move along the elongate rod with the first and second back-up shoes contacting and pivoting against the interior surfaces of the aligned first and second pipe sections. BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings, in which: FIG. 1 is a side view in partial cross section of a plug style line-up clamp forming a first embodiment of the present invention; FIG. 2 is an illustrative side view of the center member of the line-up clamp with the back-up shoes retracted; FIG. 3 is a cross-sectional view taken along line A--A in FIG. 2; FIG. 4 is an illustrative side view of the center member of the line-up clamp with the clamping shoes expanded; FIG. 5 is a cross-sectional view taken along line B--B in FIG. 4; FIG. 6 is a cross-sectional view of the center member; FIG. 7 is a top view of the back-up shoe; FIG. 8 is a side view of the back-up shoe; FIG. 9 is an inside view of the back-up shoe; FIG. 10 is a top view of the back-up shoe journal; FIG. 11 is an end view of the back-up shoe journal; FIG. 12 is a side view of the back-up shoe journal; FIG. 13 is a top view of the back-up shoe mount; FIG. 14 is a side view of the back-up shoe mount; FIG. 15 is an inside view of the back-up shoe mount; FIG. 16 is an inside view of the back-up shoe assembly; FIG. 17 is a top view of the back-up shoe assembly; FIG. 18 is a side view of the back-up shoe assembly; FIG. 19 is a cross-sectional view of the back-up shoe assembly taken along A--A in FIG. 16; FIG. 20 is a side view of a plug style line-up clamp forming a second embodiment of the present invention; FIG. 21 is an illustrative side view of the clamp of FIG. 20; and FIG. 22 is an illustrative side view of the clamp of FIG. 20. DETAILED DESCRIPTION With reference now to the accompanying drawings, a plug style line-up clamp 10 constructed in accordance with the teachings of the present invention is illustrated. As seen in FIG. 1, the line-up clamp 10 includes a guide assembly 12 mounting a hydraulic cylinder 14. The piston 16 of the hydraulic cylinder extends to a threaded end 18. The hydraulic cylinder 14 is connected to a source of hydraulic pressure, not shown, to move the piston 16 between a retracted position and an extended position. An end frame 20 is mounted to the guide assembly 12 and includes an end member 21. A center shaft 24 is threadedly coupled to the threaded end of piston 16 by a connector nut 26 and extends to a distal end 28 along axis 56. A plurality of first resilient disks 30 are positioned concentric with sliding tube 68, which, in turn, is concentric with a first portion 32 of the center shaft 24. The disk 34 at one end abuts an end plate 22 free floating on sliding tube 68. End plate 22 also abuts the end member 21. A center member 36 is free floating on the center shaft 24 and abuts disk 38 of the first plurality of disks 30. A second plurality of resilient disks 40 are concentric with sliding tube 90, which, in turn, is concentric with a second portion 42 of the center shaft, with disk 44 abutting the center member 36. An end frame 46 is mounted at the distal end 28 of the center shaft 24. An end plate 48 is free floating on sliding tube 90 and is positioned between end frame 46 and disk 50. As can be understood, hydraulic pressure entering hydraulic cylinder 14 to cause the piston 16 to retract into the cylinder will draw center shaft 24 toward the right, as seen in FIG. 1, to compress the first and second plurality of resilient disks 30 and 40 between end frames 20 and 46 and center member 36 to expand the disks 30 and 40 outward to clamp against the interior surface of adjacent first and second pipe sections 52 and 54. A mechanism of this type is disclosed in U.S. Pat. No. 5,090,608 issued on Feb. 25, 1992 which patent is incorporated herein by reference in its entirety. Mounted within the center member 36 for limited movement along axis 56 is a first actuator body 58. Mounted on the body 58 are first and second positioning links 60 and 62, each ending in a roller 64. Rollers 64 are guided within grooves 66 formed in the center member that allow the actuator body 58 to move along the axis 56, but prevent the actuator body 58 from rotating about the axis 56. First sliding tube 68 is mounted concentric with the center shaft 24 along the first portion 32 thereof. One end of the first sliding tube 68 ends in a head 70 within the center member 36. A coil spring 72 extends between the head 70 and the actuator body 58 concentric with center shaft 24. Slotted links 74 and 76 also extend between the head 70 and the actuator body 58 and engage shoulder screws 78 mounted on the actuator body 58 and head 70. The slotted links have elongated slots 80 engaging each of the shoulder screws 78 to permit limited motion of the first sliding tube 68 toward the actuator body 58 but limiting the separation between the actuator body 58 and first sliding tube 68. The opposite end of the first sliding tube 68 extends into the end member 21. A body 84 is secured on the opposite end of tube 68 with the body 84 concentric with the center shaft 24. A coil spring 82 extends between end plate 22 and body 84. Body 84 is limited from moving too far to the right as seen in FIG. 1 within end member 21 by a series of adjustable bolts 86. Bolts 86 can be adjusted to limit rightward movement of the body 84 at a selected position along the axis 56 relative to the end frame 20 and end member 21. Second actuator body 88 is also slidable along center shaft 24 within the center member 36. Actuator body 88 is substantially identical to actuator body 58 and is positioned to face body 58 as seen in FIG. 6. A second sliding tube 90 is concentric with the center shaft 24 along the second portion 42 thereof. An end of the second sliding tube 90 extends within the center member and ends in a head 92 which is connected to the second actuator body 88 by slotted links 74 and 76 and shoulder screws 78. A coil spring 98 is positioned between the head 92 and the second actuator body 88. The opposite end of the second sliding tube 90 extends into end frame 46. A body 102 is secured to the opposite end of tube 90 within end frame 46. A coil spring 100 extends between the end plate 48 and body 102. End plate 48 is free floating on sliding tube 90 relative to end frame 46. Bolts 104 can be adjusted to limit the leftward motion of body 102 along axis 56 relative to end frame 46 as seen in FIG. 1. With reference now to FIGS. 2-19, each of the actuator bodies can be seen to mount a pair of back-up shoe assemblies 106. Each back-up shoe assembly includes a back-up shoe 110, preferably formed of copper, as illustrated in FIGS. 7-9. The back-up shoe 110 can be seen to be curved to form part of an arc of a circle, with tapered ends 112 so that a first side 114 of the shoe extends only about 60 degrees of arc while the second side 116 extends about 120 degrees of arc. The outer surface 117 of the shoe 110 is curved to match the radius of the inner surface of the pipe sections to be welded, for example 3 and 11/16 inches. A series of countersunk holes 118 are formed through the shoe. Back-up shoe 110 is bolted to a back-up shoe mount 120, as illustrated in FIGS. 13-15. The mount 120 is of similar configuration to the shoe 110, including tapered ends 122, a first side 124 that extends an arc of about 60 degrees and a second side 126 which extends an arc of about 120 degrees. The outer surface 128 of the mount 120 has a series of threaded apertures 130 to receive bolts to bolt the shoe 110 thereon. At the inner surface 131, a notch 132 is formed in the middle thereof and elongate slots 134 are formed therein. The mount 120 is, in turn, secured to a back-up shoe journal 136 illustrated in FIGS. 10-12. The journal 136 has a curved portion 138 to fit within the mount 120 and bolt holes 140 to receive bolts to secure the mount 120 on the journal 136. A slot 142 is formed in the journal and a pivot pin aperture 144 extends through the journal opening into the slot 142. A link 146, seen in FIGS. 16, 18 and 19, is pivotally secured by a pivot pin 148 fit within the aperture 144. The end of link 146 opposite pin 148 is similarly pinned to the actuator body by a pivot pin 150 as seen in FIGS. 2 and 4. As best seen in FIGS. 1-5, the back-up shoe assemblies are linked to the actuator bodies 58 and 88 by links 146 with the first sides of smaller arc facing each other. The shoe assemblies on the actuator body 58 are positioned to mesh within the gaps between the back-up shoe assemblies on the actuator body 88, as seen in FIG. 2. As the hydraulic cylinder is actuated to compress the resilient disks along axis 56 and thereby expand the resilient disks into contact with the interior surface of the pipe sections being clamped, the end member 21 contacts first sliding tube 68 through bolts 86 and body 84, end frame 46 contacts second sliding tube 90 through bolts 104 and body 102 and coil springs 72, 82, 98 and 100 are compressed to urge the actuator bodies 58 and 88 toward each other. As they move toward each other, the tapered ends of each of the components of the back-up shoe assemblies engage each other and pivot the back-up shoe assemblies radially outward from axis 56 and into engagement with the interior surfaces 151 and 153 of the pipe sections 52 and 54 at the abutting ends of the pipeline to back up the weld to be performed. This motion is guided by guide rods 180 and springs 182 passing through aligned slots 134 in facing shoe assemblies. The amount of travel and force exerted by the back-up shoes on the interior surfaces of the pipe sections is controlled by the initial positioning of the bodies 84 and 102 which, in turn, are controlled by adjustment of the adjustable bolts 86 and 104. This permits screw adjustments to be made to correct for any variation in disk compression so that the back-up shoes are not overstressed against the interior surface of the pipe sections. After welding has been completed, the hydraulic pressure in cylinder 14 is relieved, permitting the disks 30 and 40 to relax to their natural state. As this occurs, the coil springs 72, 82, 98 and 100 expand as well. The springs 82 and 100 and links 74 and 76 provide a positive mechanical action to pull the actuator bodies 58 and 88 apart and pivot the back-up shoe assemblies away from the interior surfaces of the pipeline once the sliding tubes 68 and 90 move a sufficient distance away from the respective actuator bodies to take up the slack in the elongated slots 80 for the shoulder screws 78 to engage the ends of the slots. With reference now to FIGS. 20-22, a second embodiment of the invention, line up clamp 200, is illustrated. Many of the components of line up clamp 200 are identical to those in line up clamp 10, and are identified by the same reference numerals. However, push rods 202, four each per clamp half, replace tubes 68 and 90 in line up clamp 200. These push rods 202 would pass through holes in the disks 30 and 40 on the clamp halves at approximately the same bolt circle as the adjustable bolts 86 and 104. Tubes 68 and 90 would be relatively expensive and complicated to produce as compared to rods 202, and therefore use of the rods 202 can reduce the cost and complexity of the clamp. The heads 70 and 92 can be mounted in threaded inner ends 204 of the rods 202, as seen in FIG. 22. The bodies 84 and 102 are secured to the outer ends 206 of the rods 202 as seen in FIG. 21. It can be seen that the line-up clamp 10 of the present invention provides not only a mechanism for clamping pipe sections in alignment for welding, but as well provides for back-up shoes to engage the interior surfaces of the pipe sections at the weld location to enhance the weld. The clamp provides for a positive withdrawal of the back-up shoes away from the interior surfaces of the pipe sections. This positive force permits the back-up shoes to be withdrawn from the pipe sections even if some welding of the back-up shoes to the pipe sections has occurred. Although a single embodiment of the invention has been illustrated in the accompanying drawings, and described in the foregoing Detailed Description, it will be understood that the invention is not limited to the embodiment disclosed, but is capable of numerous rearrangements, modifications and substitutions of parts and elements without departing from the scope and spirit of the invention.	A line-up clamp (10) is disclosed for clamping small diameter pipe sections together for welding. The line-up clamp includes back-up shoe assemblies (106) which are pivoted into engagement with the interior surfaces of the pipe sections adjacent the weld as the clamp clamps the pipe sections. As the hydraulic cylinder (14) compresses the resilient disks, expanding the disks into clamping contact with the pipe sections, actuator bodies (58, 88) are urged together, with tapered surfaces on facing back-up shoe assemblies moving into contact and driving the back-up shoe assemblies into contact with the interior surfaces of the pipe sections at the point of welding.	1
RELATED APPLICATIONS This application is a continuation of U.S. patent application Ser. No. 13/011,776, filed on Jan. 21, 2011, which is a continuation of U.S. patent application Ser. No. 12/251,404, filed on Oct. 14, 2008, now U.S. Pat. No. 7,917,645, which is a continuation of U.S. patent application Ser. No. 10/955,841, filed Sep. 29, 2004, now U.S. Pat. No. 7,500,007, which is a continuation of U.S. patent application Ser. No. 09/511,632, filed on Feb. 17, 2000, now U.S. Pat. No. 6,834,308. U.S. patent application Ser. No. 13/011,776, U.S. Pat. No. 7,917,645, U.S. Pat. No. 7,500,007, and U.S. Pat. No. 6,834,308 are hereby incorporated by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention pertains generally to media content identification methods. More particularly, the invention is an apparatus and method for identifying media content presented on a media playing device and presenting media-content related information and/or action to the user of the media playing device. 2. The Prior Art The use of a data processing means, such as a computer or personal digital assistant (PDA), for playing works is well known. For purposes of the present discussion, a work is anything that is fixed in a tangible medium. Some examples of works include, but are not limited to, audio renderings, video renderings, images, video/audio renderings, and software. An example of an audio rendering is a song or other audio track. Examples of video renderings include animation or video sequence. Examples of an image include photographs and paintings. Examples of audio/video renderings include movies, television shows, and cartoons. Examples of software include word processing programs and video games. Some examples of playing a work include using a personal computer (PC) to play songs from audio compact disks (CD), normally with the use of a CD-ROM drive, a sound card, and speakers. Other types of media, including various formats of audio and video, are also commonly played using a PC. With the increasing popularity of the global information network commonly known as the “Internet”, various audio and video formats have been introduced to provide live (as well as archived) broadcasts of works over the Internet. These broadcasts may be viewed by users connected to the Internet with the use of a PC and the proper client application. For example, Real Networks™ provides Real Player™ (a client application) for playing streaming audio and video works (in Realm™ format) which is broadcast over the Internet, Various servers (also connected to the Internet) carry out the operation of making such works available and streaming data for the appropriate works to users upon request. In this way, Real™ media content of the work may be played by a user using Real Player™ on the user's PC. Like other media client applications, Real Player™ plays audio content of a work via the user's sound card and speakers and video content of a work via the user's video card and monitor (or other viewing device). Internet radio broadcasts (or webcasts) are also known in the art. In general, Internet radio broadcasts are provided over the Internet by one or more server computers equipped to provide streaming audio works, much like traditional AM or FM radio broadcast. A user that would like to listen to an Internet radio broadcast would use a client application (such as Real Player™, Microsoft™ media player, or Apple QuickTime™ viewer, for example) and direct the client application to the appropriate server computer. The server computer then transmits the media content of a work to the client application via the Internet. The client application receives the media content of the work transmitted from the server computer and plays the content of the work using the user's sound card and speaker. Internet video broadcasts (another form of webcast) are carried out in a similar fashion to that of Internet radio broadcasts, except video broadcasts typically contain both audio and video content of a work. As such, the audio component of the work is played to the user via a sound card and speakers, while the video component of the work is displayed usinz a video card and a monitor. In many cases, webcasts will not provide content identifying information, such as song title, artist name or album name, as part of a broadcast work. Other information, such as where the content of the work can be purchased in the form of a CD, DVD (digital video disk) or VHS (video home system) tape, for example, are also typically not included. The primary reason a webcast provider (station) fails to provide such content-related information of the work is that the station does not have real-time access to accurate playlists. For example, it is common for a station disk jockey to make real-time adjustments to the playlist order and timing. Thus current radio station systems do not transmit or attach identification data of a work with the broadcast. In addition to webcasts, many Internet sites provide archived or pre-recorded works for download and playback on a user's PC. Examples of such content of works include “way”, “mp3”, “mov”, and “midi” files, among others. Once these files have been downloaded from the Internet site to the user's PC, the user is able to play back the audio or video content of a work using an appropriate client application. Many of these media files, like webcasts, also fail to provide identifying data or other information for a work. Additionally, PCs often have the ability to play other forms of media content for other works via PC sound card and speakers and/or PC video card and monitor. For example, tuner expansion cards (tuners) which may be inserted into (or interfaced with) a user's PC are presently available (some computers already include such tuners). In either case, “television” (TV) tuners allow a user of the PC to view conventional television, cable or satellite transmissions on the PC monitor and hear the audio via the PC speaker. “Radio” tuners allow a user to hear conventional (FM or AM) radio broadcast using the PC speaker. Conventional TV and radio broadcast also fail to provide rich content-related information of a work to the user. Other media playing devices such as televisions, radio/stereo systems, and portable audio devices also typically do not provide content-related information of a work on demand for the user. For example, in automobiles, current car stereo systems fail to provide a system and method for identifying a song being played on the stereo. Typically a user would either rely on the disk jockey to identify the artist and song title or call the radio station to ascertain the information. Users may also read and/or store media content of works from storage mediums such as compact disk and magnetic tapes. Sometimes these copies of works do not include metadata or the metadata for the work may be incorrect. Furthermore, there may be no proper way to identify the work. Accordingly, there is a need for an apparatus and method which provides real-time media content-related information of a work and context specific action choices to users viewing and/or listening to media content of the work over media playing devices. The present invention satisfies these needs, as well as others, and generally overcomes the deficiencies found in the background art. BRIEF DESCRIPTION OF THE INVENTION The present invention is a system and method for identifying a work from media content presented over a media playing device, such as a computer. The system generates a media sample or analytical representation from the media content of the work, such as audio and/or video, played on the media player. The media sample or representation is compared to a database of samples of media content or representations of known works to query and ascertain content-related information related to the work. This media content-related information of the work is then displayed on the media player. The invention further relates to machine readable media which are stored embodiments of the present invention. It is contemplated that any media suitable for retrieving instructions is within the scope of the present invention. By way of example, such media may take the form of magnetic, optical, or semiconductor media. The invention also relates to data structures that contain embodiments of the present invention, and to the transmission of data structures containing embodiments of the present invention. By way of example only, and not of limitation, the media player may comprise any data processing means or computer executing the present invention including devices carrying out the invention via an embedded system. For example, the media player may comprise cellular or mobile phones, portable media players, and fixed media players including analog broadcast receivers (such as car stereo, home stereos, and televisions, for example). In a first embodiment, the database of media content samples of known works resides on a “lookup server” which carries out the database query described above. In general, the lookup server is operatively coupled for communication to one or more media players (client) via the Internet as is known in the art. Under this arrangement, media samples of works are first communicated from the client to the lookup server before the media samples are compared to the database. Then after the database query is carried out on the lookup server, the content-related information of the work is transmitted to the client for presentation thereon. According to this embodiment, the system of the present invention generally includes one or more client media players, each operatively coupled for communication to a lookup server. As noted above, the lookup server is generally connected to the client media players via an Internet connection, although any suitable network (including wired or wireless) connection may also be used. For example, the client media player may comprise a computer. The client computer typically plays audio files via a sound card and speakers. Video files are played via a video card and a monitor. The client computer has executing thereon a “client engine” software application comprising a sampling unit, a media intercept unit (intercept unit), and a user-interface. By way of example, and not of limitation, the intercept unit carries out the operation of monitoring the client computer for media content of a work presented thereon. In general, the intercept unit carries out the operation of monitoring audio signals transmitted to the sound card and/or video signals transmitted to the video card. The intercept unit may also monitor the operations of other hardware suitable for communicating audio and/or video signals, such as USB (universal serial bus) and IEEE (Institute of Electrical and Electronics Engineers) standard 1394 connections, for example. Preferably, the intercept unit maintains a FIFO (first in first out) buffer of fixed size (150 seconds, for example) containing media content played on the client. The sampling unit carries out the operation of creating a media sample from the media content of a work played on the client computer in order to represent and identify the work. In general, the sampling unit creates a sample of the work from the FIFO buffer maintained by the intercept unit. The sampling unit may create media samples from the media content of a work according to a predetermined or user-defined interval or upon the request of the user of the client computer. A user request may be received via commands issued using the user-interface. In general, the media sample created by the sampling unit comprises a “digital fingerprint” or “digital signature” using conventional digital signal processing known in the art. For example, a sound file may be sampled according to its acoustic/perceptual features over time. It is noted that “media sample” is defined herein to include actual recordings of the media content and/or analytical representations of the media content of the work. One example of such a digital signal processing technique for creating a media sample is described in U.S. Pat. No. 5,918,223 issued to Blum which is hereby incorporated by reference as if set forth in its entirety. Other examples of methods for creating media samples are given in PCT application number WO200444820 having inventors Jin S. Seo, hap A. Haitsma and Antonius A. C. M. Kalker and assigned to Koninklijke Philips Electronics and PCT application number WO03091990 having inventors Daniel Culbert and Avery Li-Chun Wang and assigned to Shazam Entertainment, Ltd. The media sample is then transmitted to the lookup server for further processing, as described in further detail below. The user interface carries out the operation of receiving commands from a user of the client computer, and displaying content-related information to the user. As noted above, a user may issue a request for content-related information via the user-interface. This request is communicated to the sampling unit for further processing. As described above, in response to this request, the sampling unit creates a sample of the media content being played on the client computer and transmits the sample to the lookup server for further processing. In response, the lookup server provides the information related to the media sample to the client computer. This content-related information is received by the user interface which then displays the received information to the user of the client computer. The content-related information for the work returned from the lookup server may also be used for a plurality of purposes including, for example, generating a log of the user activity, providing an option to purchase media to the user, and displaying the content-related information on the media playing device, among others. The lookup server has executing thereon a “server engine” software application comprising a lookup unit, and a log unit. The lookup unit is further coupled to a media database, and the log, unit is coupled to a log database. While the present invention describes the lookup server as a single machine, a group or cluster of server machines may be used to carry out the tasks of the lookup server described herein to thereby balance the load between several machines as is known in the art. The lookup unit carries out the operation of receiving media samples of the work from client computers and performing database queries on the media database to ascertain content information related to the media sample provided. This content-related information of the work may include such information as song title, artist, and album name, for example. The content-related information of the work may also include product fulfillment information, such as how and where to purchase media containing the work, advertising banners, and/or promotional offers, for example. This content-related information of the work is transmitted back to the client computer for further processing thereon. The log unit caries out the operation of tracking media requests made by the users of the client computers to the lookup server. The log unit maintains a plurality of information related to the requests made by the user including, for example, media type, genre or category. This user information is maintained in the log database. The source of the media content of the work played on the client computer includes conventional media sources such as Internet sources or webcasts, including streaming media and archived media. The media content source may also be audio CDs, DVD, or other formats suitable for presentation on media playing, devices, such as the client computer. In a second embodiment of the present invention, the database of sampled media content resides within the client computer. The database resides on conventional storage medium, such as a computer memory, a hard drive, CD-ROM, or other appropriate storage medium. Under this arrangement, the database query is carried out “locally” on the computer playing the media content. It will be readily apparent to those skilled in the art that various other topological arrangements of the system elements (including the location of the database) may be used with the invention without departing from the scope and spirit of the invention. An object of the invention is to provide an apparatus and method for identifying media content presented over a media playing device which overcomes the deficiencies of the prior art. Another object of the invention is to provide an apparatus and method for identifying media content presented over a media playing device which does not require the media content provider to provide content-related information. Further objects and advantages of the invention will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing the preferred embodiment of the invention without placing limitations thereon. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be more fully understood by reference to the following drawings, which are for illustrative purposes only. FIG. 1 is a functional block diagram of a media content identifying system in accordance with the invention. FIG. 2 is a functional block diagram of a media content identifying system having a plurality of client nodes in accordance with the invention. FIG. 3 is a flow chart showing generally the processes associated with the client engine in accordance with the invention. FIG. 4 is flow chart showing generally the processes associated with the media intercept unit in accordance with the invention. FIG. 5 is flow chart showing generally the processes associated with the server engine in accordance with the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Persons of ordinary skill in the art will realize that the following description of the present invention is illustrative only and not in any way limiting. Other embodiments of the invention will readily suggest themselves to such skilled persons having the benefit of this disclosure. Referring more specifically to the drawimzs, for illustrative purposes the present invention is embodied in the apparatus shown FIG. 1 and FIG. 2 and the method outlined in FIG. 3 through FIG. 5 . It will be appreciated that the apparatus may vary as to configuration and as to details of the parts, and that the method may vary as to details and the order of the acts, without departing from the basic concepts as disclosed herein. The invention is disclosed generally in terms of an apparatus and method for identification of a work on a personal computer, although numerous other uses for the invention will suggest themselves to persons of ordinary skill in the art. Referring first to FIG. 1 , there is generally shown a functional block diagram of a media content identifying system 10 in accordance with the invention. The system 10 comprises a lookup server 12 and at least one client media player 14 . The lookup server 12 can be any standard data processing means or computer, including a minicomputer, a microcomputer, a UNIX® machine, a mainframe machine, a personal computer (PC) such as INTEL® based processing computer or clone thereof, an APPLE® computer or clone thereof or, a SUN® workstation, or other appropriate computer. Lookup server 12 generally includes conventional computer components (not shown), such as a motherboard, central processing unit (CPU), random access memory (RAM), hard disk drive, display adapter, other storage media such as diskette drive, CD-ROM, flash-ROM, tape drive, PCMCIA cards and/or other removable media, a monitor, keyboard, mouse and/or other user interface means, a modern, and/or other conventional input/output devices. Lookup server 12 also includes a Network Interface 17 for communication with other computers using an appropriate network protocol. Lookup server 12 has loaded in its RAM a conventional server operating system (not shown) such as UNIX®, WINDOWS® NT, NOVELL®, SOLARIS®, or other server operating system. Lookup server 12 also has loaded in its RAM server engine software 16 , which is discussed in more detail below. Client media player 14 , may comprise a standard computer such as a minicomputer, a microcomputer, a UNIX® machine, mainframe machine, personal computer (PC) such as INTEL®, APPLE®, or SUN® based processing computer or clone thereof, or other appropriate computer. As such, client media player 14 is normally embodied in a conventional desktop or “tower” machine, but can alternatively be embodied in a portable or “laptop” computer, a handheld personal digital assistant (PDA), a cellular phone capable of playing media content, a dumb terminal playing media content, a specialized device such as Tivo® player, or an internet terminal playing media content such as WEBTV®, among others. As described above, client media player 14 may also comprise other media playing devices such as a portable stereo system, fixed stereo systems, and televisions suitable for use with embedded systems carrying out the operations of the client engine as described further below. Client media player 14 also includes typical computer components (not shown), such as a motherboard, central processing unit (CPU), random access memory (RAM), hard disk drive, other storage media such as diskette drive, CD-ROM, flash-ROM, tape drive, PCMCIA cards and/or other removable media, keyboard, mouse and/or other user interface means, a modem, and/or other conventional inputroutput devices. Client media player 14 also has loaded in RAM an operating system (not shown) such as UNIX®, WINDOWS® XP or the like. Client media player 14 further has loaded in RAM a media client application program 18 such as Real Player™, Windows™ Media Player, Apple Quicktime™ Player, or other appropriate media client application for playing audio and/or video via client media player 14 . Client media player 14 also has loaded in its RAM client engine software 30 , which is discussed in more detail below. Client media player 14 further includes a conventional sound card 20 connected to speakers 22 . As is known in the art, the media client application 18 will generally play audio signals through the sound card device 20 and speakers 22 . For example, audio streams, audio files, audio CDs, and other audio sources are communicated from the client application 18 to the sound card 20 for output. The sound card 18 then produces the audio signal via speakers 22 . Client media player 14 also includes a conventional video card 24 connected to a display means 26 . As is known in the art, the media client 18 will generally play video content through the video card 24 , which then produces an appropriate video signal suitable for display on the display means 26 . The display means 26 may be a standard monitor, LCD, or other appropriate display apparatus. Client media player 14 also includes a Network Interface 28 for communication with other computers using an appropriate network protocol. The network interface 28 may comprise a network interface card (NIC), a modem, ISDN (Integrated Services Digital Network) adapter, ADSL (Asynchronous digital subscriber line) adapter or other suitable network interface. Client media player 14 is networked for communication with lookup server 12 . Typically, client media player 14 is operatively coupled to communicate with lookup server 12 via an Internet connection 32 through a phone connection using a modem and telephone line (not shown), in a standard fashion. The user of client media player 14 will typically dial the user's Internet service provider (ISP) (not shown) through the modem and phone line to establish a connection between the client media player 14 and the ISP, thereby establishing a connection between the client media player 14 and the Internet 32 . Generally, lookup server 12 is also connected to the Internet 32 via a second ISP (not shown), typically by using a fast data connection such as T1, T3, multiple T1, multiple T3, or other conventional data connection means (not shown). Since computers connected to the Internet are themselves connected to each other, the Internet 32 establishes a network communication between client media player 14 and server 12 . One skilled in the art will recognize that a client may be connected to any type of network including but not limited to a wireless network or a cellular network. Generally, client media player 14 and lookup server 12 communicate using the IP (internet protocol). However, other protocols for communication may also be utilized, including PPTP, NetBEUI over TCP/IP, and other appropriate network protocols. Client media player 14 and server 12 can alternatively connect to the Internet 32 using, a network means, wireless means, satellite means, cable means, infrared means or other means for establishing a connection to the Internet, as alternatives to telephone line connection. Alternative means for networking client media player 14 and server 12 may also be utilized, such as a direct point to point connection using modems, a local area network (LAN), a wide area network (WAN), wireless connection, satellite connection, direct port to port connection utilizing infrared, serial, parallel, USB, FireWire/IEEE-1394, ISDN, DSL and other means known in the art. In general, client engine 30 is a software application executing within the client media player 14 . However, client engine 30 may also be an embedded system carrying out the functions described herein and suitable for use with various media player platforms. Client engine 30 comprises a sampling unit 34 , an intercept unit 36 , and a user interface 38 . The intercept unit 36 carries out the operation of monitoring the client media player 14 for media content of a work presented thereon, typically by media client application 18 , but may be from any media source. In operation, the intercept unit 36 monitors audio signals transmitted from the media client 18 to the sound card 20 and/or video signals transmitted from the media client 18 to the video card 24 . The intercept unit 36 may also monitor the operations of other hardware (not shown) suitable for communicating audio and/or video signals, such as USB, IEEE standard 1394 connections, and analog input devices (such as microphones). For example, in a media player comprising a mobile stereo system, the intercept unit 36 intercepts the audio signal played on thereon. Preferably, the intercept unit 36 maintains a FIFO (first in first out) buffer 40 of fixed size (150 seconds, for example) for storing media content of a work played on the client media player 14 , and from which media samples of the work are created by sampling unit 34 . The operation of the intercept unit is further described below in conjunction with FIG. 4 . The sampling unit 34 carries out the operation of creating a media sample from the media content of a work played on the client media player 14 . In operation, the sampling unit 34 creates a media sample from the FIFO buffer 40 maintained by the intercept unit 36 . The sampling unit 34 may create media samples according to a predetermined or user-defined interval or upon the request of user of the client media player 14 . For example, user requests may be received via commands issued using the user-interface 38 . As noted above, the media sample created by the sampling unit 34 typically comprises a “digital fingerprint” using conventional digital signal processing known in the art. For example, a sound file may be sampled according to its acoustic/perceptual features over time. One example of such a digital signal processing technique is described in U.S. Pat. No. 5,918,223 issued to Blum which is hereby incorporated by reference as if set forth in its entirety. Other examples are described in PCT application number WO200444820 having inventors Jin S. Seo, Lap A. Haitsma and Antonius A. C. M. Kalker and assigned to Koninklijke Philips Electronics and PCT application number WO03091990 having inventors Daniel Culbert and Avery Li-Chun Wang and assigned to Shazam Entertainment, Ltd. The media sample generated by sampling unit 34 is then transmitted to the lookup server 12 for further processing, as described in further detail below. The user interface 38 carries out the operation of receiving commands from a user of the client media player 14 , and displaying content-related information to the user. The user interface 38 may be any conventional interfaces including, for example, a graphical user interface (GUI), a command line user interface (CLUI), a voice recognition interface, a touch screen interface, a momentary contact switch on a stereo system, or other appropriate user interface. In operation, a user may issue a request for content-related information via the user-interface 38 . This request is communicated to the sampling unit 34 for further processing. As described above, in response to such a request, the sampling unit 34 creates a media sample from the media content of a work being played on the client media player 14 and transmits the sample to the lookup server 12 for further processing. In response, the lookup server 12 provides the information related to the work, if available, to the client media player. This content-related information of the work is received by the user interface 38 which then displays the received information to the user of the client media player 14 . The server engine 16 is a software application executing within the lookup server 12 . Server engine 16 comprises a lookup unit 42 and a log unit 44 . Lookup unit 42 is operatively coupled for communication with a media database 46 . Log unit 44 is operatively coupled for communication with a log database 48 . The lookup unit 42 carries out the operation of receiving media samples from the client media player 14 and comparing the media samples to a collection of samples of the media content of known works (reference samples). The collection of reference samples of known works will typically reside in an in-memory structure (designated 47 ). Upon initialization of the lookup unit 42 , the collection of reference samples of known works from the media database 46 is stored in the in-memory structure 47 . The lookup unit 42 sequentially compares each reference sample of known works in structure 47 to the media sample provided by the media player 14 . The lookup unit will cut a media sample of the received work into a series of overlapping frames, each frame the exact size of the particular reference sample under examination. The lookup unit 42 will then compare the reference sample to every possible “frame” of information within the media samples of the known works and compute a “distance” between each frame and the reference sample. This process repeats for each reference sample. The reference sample which has the smallest distance to any frame in the sample is considered for a match. If this distance is below a predefined threshold, a match is considered to be found. When a match is determined, the information related to the matching record of the known work is returned to the client media player for presentation thereon. This content-related information of a work may include such information as song title, artist, and album name, for example. The content-related information may also include product fulfillment information, such as how and where to purchase media containing the media sample, advertising banners, and/or promotional offers, for example. This content-related information of the work is transmitted back to the client media player 14 for further processing thereon. The log unit 44 caries out the operation of tracking media requests made by the users of the client media player 14 to the lookup server 12 . The log unit 44 maintains a plurality of information related to the requests made by the user including, for example, media type, genre or category. This user information is maintained in the log database 48 Media database 46 and log database 48 comprise conventional relational database storage facilities. Thus, media database 46 may comprise one or more tables (not shown) for storing data associated with the media content samples of known works and related content-specific information (song name, title, album name, etc.) of the known works. In general, another computer (not shown) may be connected to the lookup server 12 for entering the content-specific media information into the media database 46 . Log database 46 may comprise one or more tables (not shown) for storing data associated with users and the user's related media content requests. Referring now to FIG. 2 , there is generally shown a functional block diagram of a media content identifying system 50 having a plurality of client nodes in accordance with the invention. System 50 comprises a lookup server 54 operatively coupled for communication with a plurality of client media players 52 a through 52 n via Internet connection 32 . System 50 operates in substantially the same manner as system 10 described above. That is, lookup server 54 operates in the same manner as lookup server 12 , and clients 52 a through 52 n operate in the same manner as client media player 14 . However, in system 50 , lookup server 12 handles a plurality of media sample identification requests from the client 52 a through 52 n. As depicted in FIG. 2 , clients 52 a through 52 n communicate with lookup server 54 using the HTTP (hypertext transfer protocol) over IP. Although http is used in the example, one skilled in the art will recognize that any suitable protocol may be used. More particularly, the media sample signal generated by each client 52 a through 52 n is wrapped using a transport protocol before being transmitted over HTTP to lookup server 54 for processing. When lookup server 54 receives the HTTP transmission from the client media player, a transport protocol converts (“unwraps”) the signal for processing therein by the server engine. Likewise, before transmitting content-related information retrieved from the media database to the appropriate client media player, the information is first wrapped using the transport protocol. The content-related information may be communicated using “XML” tags, or other appropriate programming, scripting, or markup language. The appropriate client media player upon receiving the transmission from the lookup server 54 unwraps the signal for processing therein by the client engine. The method and operation of the invention will be more fully understood by reference to the flow charts of FIG. 3 through FIG. 5 . The order of acts as shown in FIG. 3 through FIG. 5 and described below are only exemplary, and should not be considered limiting. Referring now to FIG. 3 , as well as FIG. 1 and FIG. 2 , there is shown the processes associated with the client engine 30 in accordance with the invention. As described above, the client engine 30 is a software application or embedded system operating within a client media player for identifying media content played via the client media player. At process 100 , the client engine 30 is initiated. The client engine 30 may be initiated by the user of client media player 14 or may initiate automatically upon the recognition of media content being played via the sound card 20 and/or the video card 24 . Box 110 is then carried out. At box 110 , the intercept unit 36 is initiated. As described above, the intercept unit 36 carries out the operation of monitoring media content of a work played on client media player 14 (typically via sound card 20 and/or video card 24 ). The processes of the intercept unit 36 are described more fully below in conjunction with FIG. 4 . After the intercept unit 36 is initiated, box 120 is then carried out. At box 120 , a user request for media information is received via user interface 38 . This request is communicated from the user interface 38 to the sampling unit 34 for further processing. Box 130 is then carried out. At box 130 , the sampling unit 34 creates a media sample from the media data of a work contained in the FIFO buffer 40 . The media sample created by the sampling unit 34 comprises a “digital fingerprint” using conventional digital signal processing known in the art. As noted above, a sound file may be sampled according to its acoustic/perceptual features over time. Box 14 is then carried out. At box 140 , the sampling unit 34 transmits the media sample created from box 130 to the lookup server 12 for content identification and content-related information. In the illustrative system depicted in FIG. 1 and FIG. 2 , the media sample is first wrapped in a transport protocol and then communicated over IP (HTTP) via network interface 28 . Box 150 is then carried out. At box 150 , the client media player 14 receives from the lookup server 12 the content-related information of the work requested in box 140 . The process for generating the content-related information by the lookup server 12 is described in further detail below in conjunction with FIG. 5 . This content data is first received via the network interface 28 , unwrapped using the appropriate transport protocol and then communicated to the client engine 30 . In the client engine 30 , the user interface 38 receives the content-related information, and parses the data according to the appropriate format (XML tags, for example) transmitted by the lookup server 12 . Box 160 is then carried out. At box 160 , the user interface 38 presents the content-related information of the work to the user via video card 24 and display 26 , or other display device such as an LCD screen, or standard broadcast television. As described above, this content-related information of the work may include such information as song title, artist, and album name, for example. The content-related information of the work may also include product fulfillment information, such as how and where to purchase media containing the media sample, advertising banners, and/or promotional offers, for example. Referring now to FIG. 4 , there is generally shown the processes associated with the media intercept unit 36 in accordance with the invention. In general, the media intercept unit 36 maintains a FIFO buffer of predetermined size (150 seconds, for example) of media content played via client media player 14 , 52 a through 52 n. At process 200 , the intercept unit 36 is initiated. This is carried out from box 110 of FIG. 3 , during the start up of the client engine software 30 . Box 210 is then carried out. At box 210 , the intercept unit 36 monitors the media hardware devices of the client media player 14 . As described above, the media hardware devices may comprise a sound card 20 and/or a video card 24 . Other hardware devices suitable for playing media content are also monitored by the intercept unit 36 . Diamond 220 is then carried out. At diamond 220 , the intercept unit 36 determines whether any media hardware devices are playing media content of a work. If the intercept unit 36 determines that media content is currently being played, diamond 230 is carried out. Otherwise box 210 is repeated. At diamond 230 , the intercept unit 36 determines whether the FIFO buffer 40 is currently full. If the buffer is determined to be full, box 240 is carried out. Otherwise, box 250 is carried out. At box 240 , the intercept unit 36 has determined that all the buffer 40 is full and deletes the older sample in the buffer. As noted above, the FIFO buffer 40 is commonly configured with a predetermined size. For example, if the sampling rate is 22 KHz (HiloHertz), the oldest 1122000 th of a second sample would be deleted, and the newest 1/22,000 th of a second sample would be added to the buffer. Using this method, the intercept unit 36 is able to maintain the most recent one hundred fifty (150) seconds of media content of a work played via client media player 14 . Box 250 is then carried out. At box 250 , the intercept unit 36 stores the media content of the work currently being played on client media player 14 into the FIFO buffer 40 . Box 210 is then repeated to continue monitoring media hardware devices. Referring now to FIG. 5 , there is generally shown the processes associated with the server engine 16 and the lookup server 12 in accordance with the invention. It is noted that the lookup server 12 is structured and configured to handle a plurality of requests from a plurality of client media players as depicted in FIG. 2 above. Prior to box 300 as described below, the in-memory structure 47 is populated with reference media samples of known works. Upon initialization of the lookup unit 42 , the collection of reference samples from the media database 46 is stored in the in-memory structure 47 . At box 300 , the lookup server 12 receives a media sample request from one of the client media players 14 , 52 a through 52 n . As described above, such requests are generally communicated over an Internet connection 32 , although any suitable network connection may also be used. The request is first received via network interface 17 via the IP (HTTP) protocol or other suitable protocol. An appropriate transport protocol unwraps the message and communicates the request to the server engine 16 for processing. Box 310 is then carried out. At box 310 , the lookup unit 42 sequentially compares each reference sample of the known works in structure 47 to the media sample of the work provided by the media player 14 , 52 a through 52 n , as described above. The lookup unit will cut the media sample into a series of overlapping frames, each frame the exact size of the particular reference sample under examination. The lookup unit 42 will then compare the reference sample to every possible “frame” of information within the media sample and compute a “distance” between each frame and the reference sample. This process repeats for each reference sample. Diamond 320 is then carried out. At diamond 320 , the lookup unit 42 determines whether a match was obtained. As noted above, the reference sample of the known work which has the smallest distance to any frame in the sample is considered for a match. If the distance is below a predefined threshold, a match is considered to be found. If a match is determined, box 330 is then carried out. Otherwise box 350 is carried out. At box 330 , the media sample from box 300 matches a corresponding record in the media database 46 , and the lookup unit 42 retrieves the content-related information of the known work associated with the matching record in the media database 46 . As noted above, this content-related information may include such information as song title, artist, album name, for example as well as other information such as product fulfillment information such as a sponsor or an advertiser. Box 340 is then carried out. At box 340 , the content-related information of the known work obtained in box 330 is transmitted to the client media player submitting the media sample request in box 300 . In the preferred embodiment, this transmission is carried out over the Internet using the IP (HTTP) protocol or other suitable protocol. Box 370 is then carried out to generate a log. At box 350 , the lookup unit 42 has determined that the media sample of the work from box 300 does not match any reference sample in the in-memory structure 47 . Box 360 is then carried out. At box 360 , a notice indicating that the requested information is not available is transmitted to the requesting client media player of box 300 . Box 370 is then carried out. At box 370 the log process is initiated. This log process involves tracking the user and related-media information associated with the request of box 300 . The log unit 44 maintains a plurality of information related to the requests made by the user including, for example, media type, genre or category. This user information is maintained in the log database 48 and may be used for various marketing strategies, including analyzing user behavior, for example. Accordingly, it will be seen that this invention provides an apparatus and method which provides real-time media content-related information to users viewing media content over a personal computer, or other data processing means. Although the description above contains many specificities, these should not be construed as limiting the scope of the invention but as merely providing an illustration of the presently preferred embodiment of the invention. Thus the scope of this invention should be determined by the appended claims and their legal equivalents.	A computing device executing a server engine receives a digital fingerprint created from a segment of a work, the work being a single rendering, the segment being less than an entirety of the work, and the digital fingerprint being based on perceptual features of the segment. The computing device compares the digital fingerprint to a plurality of digital fingerprints from a plurality of known works to identify a known work of the plurality of known works that corresponds to the work. The computing device transmits content-related data associated with the known work to a client device.	6
BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a voltage control device for controlling a voltage used for driving, for example, a motor operated with a high internal impedance battery employed as a power source. 2. Description of the Related Art Generally, the devices of the above-stated kind have been arranged to operate in one of two different modes, one mode when the motor is rotated and in another mode when the motor is in repose. Some of them are arranged to have the motor driven at a high voltage when the motor is rotating and to have a weak current continuously applied at such a low voltage that never causes any phase deviation of the motor when the motor is in repose. In cases where a battery is used as a power source, the method of continuously applying a weak current when the motor is in repose has not been adopted for the purpose of saving the electrical energy of the battery from being wasted. In this case, the above-stated method is replaced with a method, wherein, before rotating the motor, a phase at which the motor is brought to a stop at the end of a previous operation is excited for a given period of time T0, as shown in FIG. 8 of the accompanying drawings, in such a way as to adjust the phase of control to the actual phase of the motor. This method prevents the motor from going out of control due to any slight phase deviation that occurs when the motor is previously brought to a stop. An example of this method has been disclosed, as a stepping motor control method, for example, in Japanese Lid-Open Patent Application NO. SHO 59-201885. Further, in a case where the motor is to be driven at a low voltage by means of a battery, the battery consumption can be lessened by preventing the current from being wasted in the following manner. In some cases, not much current is required in obtaining a required amount of torque, while a relatively greater amount of current is required in other cases. Therefore, the battery consumption can be lessened by varying the required amount of driving voltage stepwise, to several values. In FIG. 8, a reference symbol ΔVB3 denotes a fluctuating range of the power supply voltage. In such a case, as shown in FIG. 8, a stop-phase exciting action for phase adjustment is carried out after the driving voltage is changed to a value between a voltage VM0 and VM1. (In the case of FIG. 8, a rush current preventing capacitor which will be described later herein is not inserted.) However, in driving the motor after changing the driving voltage from a low voltage VM0 to a high voltage VM2 as shown in FIG. 8, the conventional device presents the following problems. (1) With the driving voltage values (VM0 to VM2) arranged stepwise, the battery voltage drops when the motor phase adjustment is performed at a high voltage. As a result, a conversion efficiency of a voltage converter which converts the battery voltage to the motor driving voltage or that of some other voltage converter disposed within the same apparatus might be lowered. This eventually shortens the life of the battery. (2) If the motor is caused to rotate immediately after adjustment of the stop phase thereof, a large power supply is required from the battery because of a large load. In that case, as shown in FIG. 8, the battery voltage VB is dropped by the phase adjustment and also gradually drops after the start of the motor rotation. Therefore, this brings about the same result as in the case of the problem (1) above. SUMMARY OF THE INVENTION This invention is directed to the solution of the above-stated problems. It is, therefore, an object of the invention to provide a motor driving voltage control device which is arranged to prevent the battery voltage from dropping to an excessive degree. It is another object of the invention to provide a motor driving voltage control device which is capable of preventing a motor driving voltage from being lowered by a drop in the battery voltage. These and further objects and features of the invention will become apparent from the following detailed description of embodiments thereof taken in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing the arrangement of a first embodiment of the invention. FIG. 2 shows a relation obtained between voltage values and excitation by the first embodiment. FIG. 3 is a flow chart showing the motor control operation of the first embodiment. FIG. 4 is a block diagram showing the arrangement of a second embodiment of the invention. FIG. 5 shows a relation obtained between voltages and excitation by the second embodiment. FIG. 6 is a flow chart showing the motor control operation of the second embodiment. FIG. 7 shows a voltage-to-excitation relation obtained by a third embodiment of the invention. FIG. 8 shows a voltage-to-excitation relation obtained by a conventional device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Below is described in detail preferred embodiments of the invention with reference to the accompanying drawings: First Embodiment A first embodiment of the invention is arranged as follows. FIG. 1 shows in a block diagram the arrangement of the first embodiment. Referring to FIG. 1, a CPU 1 is arranged to control the entire device. A timer 25 is arranged within the CPU 1 to control the timing of various processes to be performed within the device. A ROM 2 is arranged to store a control program, an error processing program and a program shown in a flow chart by FIG. 3 as will be described later herein. A RAM 3 serves as a work area for the various programs and a temporary shelter area for error processing. Further, the CPU 1 is arranged to send out data, an address signal and a read/write (hereinafter referred to as R/W) signal via bus lines. A control port 4 is arranged to produce signals L1 and L2 for designating a motor driving voltage, motor exciting signals M0 to M3 for driving a stepping motor 21 and a signal EN for designating strong excitation or weak excitation according to data obtained from the CPU 1. A battery 5 is employed as a power source for the device. A voltage converter 6 is arranged to convert the voltage VB of the battery 5 into a motor driving voltage VM. Voltage dividing resistors 7, 8, 9 and 10 are arranged to determine the voltage levels of the motor driving voltage VM (VM0 to VM2). A Zener diode 14 is arranged to produce reference voltages for the divided voltage values of the voltage dividing resistors 7, 8, 9 and 10. A transistor 13 is arranged to cause a Zener voltage to be reflected on the divided voltages obtained by the resistors by applying a Zener current to the Zener diode 14. Inverters 11 and 12 serve as open collectors for selecting the voltage dividing resistors 8 and 9. A capacitor 15 is arranged to gradually change the motor driving voltage by preventing a rush current which takes place when the motor driving voltage VM is changed from a low voltage to a high voltage by means of the voltage dividing resistors 7 to 10. A capacitor 16 is provided for stabilizing the motor driving voltage VM. The stepping motor 21 has four phases. A motor driver. 22 is arranged to drive each phase of the stepping motor 21. A transistor 19 is provided for selection of a driving voltage to be applied to the stepping motor 21 between a driving voltage for strong excitation and a holding voltage for weak excitation. An inverter 20 which is an open collector is provided for turning on and off the transistor 19. A resistor 18 is provided for limiting the base current of the transistor 19. A resistor 17 is provided for firmly setting the level of the transistor 19. A resistor 23 is arranged to limit a current for holding the stepping motor 21. A diode 24 is arranged to prevent any flow of a current from the motor driving voltage VM to the battery 5. The CPU 1 is arranged to operate in accordance with each of the programs of varied kinds stored in the ROM 2. The operation of the CPU 1 can be roughly divided into the following actions. One is performed to change stepwise the motor driving voltage VM from one voltage value over to another. Another action is performed to change the stepping motor driving mode between a strong exciting mode and a weak exciting mode. The third action is performed to rotate the stepping motor 21. These three actions of the CPU 1 are described in detail below. The stepwise changing action of the motor driving voltage VM is first described. This action is performed by the signals L1 and L2 of the control port 4. In the case of L1=L2="L" (a low level), for example, the outputs of both the inverters 11 and 12 which are open collectors are open. Therefore, the driving voltage VM is determined by a voltage value VR which is divided by the resistors 7 and 10. The voltage value VR is determined by the value of the Zener diode 14. The driving voltage VM may be expressed by the following formula (1): ##EQU1## Then, the motor driving voltage thus obtained in this instance is assumed to be VM0. Next, in the case of L1="H" (high level) and L2="L", the output of the inverter 12 is grounded. The driving voltage VM is then expressed as follows: ##EQU2## The motor driving voltage thus obtained is assumed to be VM1. Further, in the event of L1="L" and L2="H", the output of the other inverter 11 is grounded. Therefore, the driving voltage VM is expressed as follows: ##EQU3## The value thus obtained is assumed to be VM2. In Formula (3) above, (RA // RB) represents parallel resistance values RA and RB. In accordance with Formulas (1) to (3), the driving voltage VM can be set at a desired value by selecting the resistance values R, R0, R1 and R2 as desired. This permits selection of a relation VM0<VM1<VM2. The capacitor 15 is used for the purpose of mitigating any rush current flowing to another capacitor 16 as a result of a low input impedance obtained at the voltage converter 6 when, for example, a low driving voltage, such as the voltage VM0, changes to a higher driving voltage, such as the voltage VM1. In this case, the driving voltage VM can be gradually changed by virtue of the capacitor 15. The second action for change-over between the strong excitation and the weak excitation is performed as follows: The second action is performed by means of the signal EN of the control port 4. In the case of EN="H" (when the signal EN is at a high level), the output of the inverter 20 which is an open collector is grounded. Therefore, a base current flows via the resistor 18 to the transistor 19 to turn on the transistor 19. As a result, the driving voltage VM is supplied to the common terminal of the stepping motor 21. In this case, if any of the motor phase terminals of the motor driver 22 is turned on by the motor exciting signals M0 to M3 from the control port 4, (the number of phases to be turned on varies with the driving method), a current flows to the stepping motor 21. This brings the motor into a strongly excited state. In the event of EN="L" (when the signal EN is at a low level), the output terminal of the inverter 20 is opened to turn off the transistor 19. In that case, a voltage is supplied from the battery 5 to the common terminal of the stepping motor 21 via the resistor 23 and the diode 24. If any of the phase terminals of the motor driver 22 have been turned on by the signals M0 to M3 under this condition, there flows a current which does not give any sufficient torque for rotating the stepping motor 21 but gives a torque large enough for holding the rotor of the stepping motor 21. In that instance, there obtains a weak exciting state. Further, in the case of the first embodiment, the value of the current obtained when the battery 5 is in the initial service stage differs from the current value obtainable in the last service stage of the battery 5. In view of this, this embodiment is preferably applied to an apparatus which allows a certain amount of margin to the range of the holding torque values. The third action of rotating the stepping motor 21 is performed in the following manner. In the case of this action, the embodiment is set in a strong exciting mode, that is, EN="H". The motor exciting signals M0, M1, M2 and M3 are serially changed from one over to another by turns. By this, the stepping motor 21 is rotated by repeatedly turning on and off each phase part of the motor driver 22. The timing for this action is determined by the timer 25 which is disposed within the CPU 1. The first embodiment which is arranged as described above operates in the following manner. FIG. 2 shows a relation obtained between the voltage and the exciting action of the first embodiment. FIG. 3 shows in a flow chart the motor control operation of the first embodiment. A phase adjusting action for adjusting the actual stop phase of the stepping motor 21 to the current stop phase of the stepping motor 21 stored in the RAM 3 is performed by strongly exciting the stop phase of the motor 21 for a given period of time T0. This period of time T0 is a strong excitation time necessary for stop-phase excitation. In this instance, the motor driving voltage VM is set at the lowest voltage value VM0 for the purpose of minimizing the consumption of the battery 5. For this purpose, both the signals L1 and L2 are set at a low level "L", at a step S1 in the flow of the motor control operation. At a step S2 the signal EN is set at a high level "H" to turn on the transistor 19 in order to start the strong exciting operation. At a step S3 the stepping motor exciting signals M0 to M3 are produced in such a way as to turn on the current stop phase stored at the RAM 3. At a step S4, to set the strong stop-phase exciting time T0, the timer value T of the timer 25 is set at a value T0 for time measurement. At a step S5: an ensuing action is held in abeyance until the timer 25 counts the time T from the value T0 down to zero. This allows the strong stop-phase excitation to be carried out over the length of time T0. While the stop phase of the motor is thus strongly excited, the battery voltage VB gradually drops as shown in FIG. 2. Following this, the driving voltage of the stepping motor 21 is changed according to the action of the apparatus. In that instance, if the driving voltage necessary for the next action is the voltage VM1 or VM2, the driving voltage changes from the voltage VM0 to the voltage VM1 or VM2. In this case, the capacitor 15 acts to cause the voltage to gradually rise as mentioned in the foregoing and, therefore, some period of time is required for the change. As shown in FIG. 2, the greater potential difference from the motor driving voltage VM0 to the voltage VM2 requires a longer period of time. If a strong exciting action is carried out during this changing period of time, the voltage VB would drop as the current flowing to the stepping motor 21 increases, and thus the life of the battery would eventually be affected by this. To avoid the adverse effect of this on the battery, the first embodiment is arranged to perform a weak exciting action during the above-stated changing period. At a step S6, for the above-stated purpose of weakly exciting the stop phase, the signal EN is set at a low level to turn off the transistor 19. Then, a weak exciting current is supplied from the battery 5 through the resistor 23 and the diode 24. At a step S7 a check is made for a driving voltage VM required for a next action. If the driving voltage required is found to be the voltage VM0, the flow of operation comes to a step S13. If the voltage required is VM1, the flow proceeds to a step S8. At a step S8 the signal L1 is set at a high level and the signal L2 at a low level to cause the motor driving voltage VM to be set at the voltage value VM1. At a step S9, after the step S8, a period of time T1 for a change from the voltage value VM0 to the voltage value VM1 is set at the timer 25. At a step S12 the flow of the operation waits till the value T of the timer 25 is counted down from a value T1 to zero. If the driving voltage required for the next action is found to be the voltage value VM2 at the step S7, the flow comes to a step S10. At the step S10 the motor driving voltage VM is set at the voltage value VM2. At a step S11 a period of time T2 required for the change from the voltage value VM0 to the voltage value VM2 is set at the timer 25. The flow then comes to the step S12 to wait till the timer 25 counts down from the time T2 to zero. The time values T1 and T2 are set to allow ample margins over and above an actual build-up time for a possible error in the capacity of the capacitor 15. With the stop phase weakly excited in this manner, the voltage VB at first somewhat drops because of the change in the motor driving voltage VM. After that, a load obtained during the period of time T0 decreases. Therefore, the voltage VB is brought back to its original value by setting the resistor 23 at a desired value as shown in FIG. 2. At steps S13 and S14 the motor driving voltage VM is considered to have reached the set voltage value and the stepping motor 21 begins to actually rotate. More specifically, the signal EN which has been set on the side of weak excitation is again set at a high level for strong excitation at the step S13. After that, at the step S14, the stepping motor 21 is caused to actually rotate from a step next to the stop phase thereof to the extent of a necessary number of steps of the motor by the motor exciting signals M0 to M3. At a step S15: The signal EN is set at a low level for weak excitation for the purpose of bringing all the four phases of the stepping motor 21 to a stop. At a step S16: The motor exciting signals M0 to M3 are turned off. With the stepping motor 21 rotated in this manner, the battery voltage VB drops as shown in FIG. 2. After that, the level of the voltage VB varies up and down according to the mode of driving the stepping motor 21. The voltage VB again comes back to the original level thereof when the motor 21 is turned off. In changing the motor driving voltage VM from the voltage value VM1 to the voltage value VM2, the motor driving voltage VM is at first lowered to the lowest voltage value VM0 for the strong stop-phase excitation. The strong stop-phase exciting action is performed under this condition. Therefore, in this instance, the battery voltage VB drops in the same manner as during the period of time T provided for changing the motor driving voltage VM from the voltage value VM0 to the voltage value VM1. Further, the potential difference is larger for changing the motor driving voltage VM from the voltage value VM0 to the voltage value VM2 than for changing it from the voltage value VM0 to the voltage value VM1. Therefore, the battery voltage VB drops to a little greater degree within the period of time T2 than within the period of time T1. After this change, the battery voltage VB changes for the weak excitation as shown in FIG. 2. The changing degree of the battery voltage VB fluctuates according to the size of the load on the stepping motor 21, the size of the input impedance of the voltage converter 6, the efficiency of the voltage converter 6, etc. The width ΔVB1 of the changes in the battery voltage VB is less than the width ΔVB3 of the battery voltage changes as shown in FIG. 8. This indicates that the change width of the battery voltage VB is effectively suppressed by the arrangement of the first embodiment. As described above, the first embodiment is arranged to prevent the battery voltage from excessively dropping and is thus capable of preventing the stepping motor driving voltage, etc. from being lowered by the drop of the battery voltage. Therefore, the life of the battery can be lengthened. Second Embodiment Next, a second embodiment of the invention is described as follows. FIG. 4 shows in a block diagram the arrangement of the second embodiment. In FIG. 4, the parts of the second embodiment which are indicated by the same reference numerals as in FIG. 1 are arranged to act in the same manner as in the case of the first embodiment. Therefore, the details of them are omitted from the following description. A reference voltage generator 38 is arranged to generate a voltage which is to be used as a reference for voltage conversion. Comparators 39 and 45 are arranged to compare voltages obtained by dividing a voltage by means of resistors with the reference voltage VREF generated by the reference voltage generator 24 for determining voltages VH and VM and to turn on and off voltage converters 34 and 44 according to the results of comparison. Voltage dividing resistors 40 and 41 are provided for determining the voltage VH which is to be used for holding (weakly exciting) the stepping motor 21. A capacitor 42 is arranged to stabilize the holding voltage VH. A diode 43 is provided for cutting off a current flow from the motor driving voltage VM to the holding voltage VH. The motor driving voltage VM is higher than the motor holding voltage VH in the same manner as in the case of the first embodiment. A CPU 31 is arranged to control the whole device of the second embodiment. A ROM 32 is arranged to store therein a control program, an error processing program and a program which is arranged according to a flow chart shown in FIG. 6. A RAM 33 is arranged to serve as work areas for various programs and a temporary shelter area in the case of error processing. A voltage detector 35 includes a timer 36 which is arranged to function in the same manner as the timer 25 of the first embodiment and a status register 37 which is provided for setting interruption information as will be described later herein. In performing the roughly divided three actions stated in the foregoing description of the first embodiment, the second embodiment operates as follows. The first action of changing stepwise the motor driving voltage VM is performed by means of the signals L1 and L2 of the control port 4 in the same manner as in the case of the first embodiment. However, the voltage values VM0, VM1 and VM2 of the motor driving voltage VM are expressed according to the levels of the signals L1 and L2 in the following manner: In the case of L1=L2="L", the driving voltage value VM0 is obtained as expressed below: ##EQU4## In the case of L1="H" and L2="L", the driving voltage value VM1 is obtained as expressed below: ##EQU5## In the case of L1="L" and L2="H", the driving voltage value VM2 is obtained as expressed below: ##EQU6## The motor driving voltage values can be obtained in a relation of VM0<VM1<VM2 according to the above formulas (4), (5) and (6) by suitably selecting resistance values R, R0, R1 and R2. Meanwhile, the holding voltage VH is expressed as follows: ##EQU7## The voltage values can be obtained in a relation of VH<VM0<VM1<VM2 according to the formulas (4) to (7) by suitably selecting resistance values R3 and R4. The second action of changing the motor driving mode between strong and weak exciting actions is performed by means of the transistor 19. In the case of the second embodiment, the strong exciting action is performed by driving the motor with the motor driving voltage VM while the weak exciting action is performed by driving the motor with the holding voltage VH. The first embodiment is arranged to perform the weak exciting action by directly driving the motor with the power supply effected from the battery 5 via the resistor and the diode. This has caused a holding current to fluctuate according to the level of the life of the battery. Although this arrangement of the first embodiment presents no problem depending on the kind of the apparatus to which the invention is applied, the second embodiment is arranged with importance attached to the holding current. In other words, in the case of the second embodiment, the stepping motor 21 is held by the holding voltage VH which is stabilized by means of the voltage converter 34. Further, the arrangement of the second embodiment differs from that of the first embodiment with respect of the provision of the voltage detector 35. The voltage detector 35 is arranged to permit an interrupt signal INT to be applied to the CPU 31 when the data for a voltage value written and obtained from the CPU 31 comes to coincide with the motor driving voltage VM. The signal INT is used for the purpose of confirming that the motor driving signal VM has reached a given value during its changing process. This arrangement prevents the voltage varying time from being wasted due to an error in the capacity of the capacitor 15 as mentioned in the foregoing description of the first embodiment. At this voltage detector 35, detection voltage values VM1' and VM2' are set as shown in FIG. 5. These voltage setting values must be arranged to differ from the actual motor driving voltage values VM1 and VM2 only as much as ΔVM which permits the stepping motor 21 to be adequately driven. Further, at the voltage detector 35, a setting time T is measured by the timer 36. Upon the lapse of a time T0 or a detection time Tx, for example, the signal INT is supplied to the CPU 31. The signal INT is supplied to the CPU 31 also when the detection voltage value VM1' or VM2' is detected while the motor is rotating. Upon detection of the signal INT while the motor is rotating, the CPU 31 reads and takes in the contents of the status register 37 disposed within the voltage detector 35. This enables the CPU 31 to make a discrimination between an interruption resulting from detection of the voltage value and an interruption resulting from the lapse of the detection time Tx as measured by the timer 36. The operation of the second embodiment is further described as follows. FIG. 5 shows a relation obtained between the voltage and excitation according to the arrangement of the second embodiment. FIG. 6 shows in a flow chart the motor control operation of the second embodiment. The second embodiment as a whole performs the motor control operation approximately in the same manner as the first embodiment. A difference between them lies in that either the operation is furthered or an error processing action is performed according to the signal INT detected by the voltage detector 35. Referring to the flow chart, the motor control operation is described as follows: At steps S20 to S22 the motor is driven at the current stop phase in the strong excitation mode in the same manner as in the case of the first embodiment. After that, the flow comes to a step S23. At the step S23 the timer 36 of the voltage detector 35 is set at a strong exciting time T0 for the stop-phase exiting action. At a step S24 the CPU 31 makes a check for the signal INT received from the voltage detector 35. If the signal INT is found to have been received, the flow of operation comes to a step S25. At the step S25 it is assumed that the period of time T0 necessary for the strong exciting action has elapsed and the stop-phase exciting action is shifted to the weak exciting mode. At a step S26 a check is made for the next value of the motor driving voltage VM. If the next voltage value of the motor driving voltage VM is found to be the voltage value VM0, the flow of operation comes to a step S36. At the step S36 the stop-phase exciting mode for the stepping motor 21 is changed to the strong exciting mode for rotating the motor in the same manner as in the case of the first embodiment. In steps S37 and S38 when the stepping motor 21 which is at the stop phase is rotated to an extent of a given number of steps from the stop phase, the motor driving action is changed over to the weak exciting mode. At a step S39 all the four phases of the stepping motor 21 are turned off. If the next voltage value of the motor driving voltage VM is found to be the voltage value VM1 or VM2 at the step S26, the flow of operation comes to a step S27 or S30. At the step S27 or S30 the motor driving voltage VM is set at the voltage value VM1 or VM2. At a step S28 or S31 at the voltage detector 35, the detection voltage VM1' or VM2' is set accordingly. At a step S29 the timer 36 is set at the detection time Tx for the purpose of detecting whether or not the above-stated detection voltage value VM1' or VM2' is detected by the voltage detector 35 within a given period of time. Then, the flow comes to a step S32. At the step S32 the flow waits for the generation of the interrupt signal INT. Upon receipt of the signal INT, the flow comes to a step S33. At the step S33: The CPU 31 reads and takes in the contents of the status register 37 of the voltage detector 35. The contents of the register 37 is checked for the reason why the interruption (by the signal INT) is made. If the reason for the interruption is found to be the detection of voltage VM1' or VM2', the flow comes to a step S35. At the step S35 the value of the timer 36 is cleared to zero to prevent the occurrence of any timer interruption during the ensuing process of the operation. The ensuing steps S36 to S39 are executed as described above. Further, if the interruption is found at the step S33 to be the timer interruption which has resulted from the lapse of the detection time Tx before the motor driving voltage VM reaches the detection voltage VM1' or VM2', the flow comes to a step S34 to perform an error processing action and the flow of operation comes to an end. Next, the relation which obtains among voltage values when the motor driving voltage VM varies from the voltage value VM0 to the voltage value VM1 and from VM1 to VM2 is described in detail below along with a difference of the second embodiment from the first embodiment. The difference from the first embodiment lies in the period of time for weakly exciting the current stop phase of the motor. In a case where the motor driving voltage VM changes from the voltage value VM0 to the voltage value VM1, the weak exciting period is determined by the time T1' required before the motor driving voltage VM reaches the detection voltage VM1' set at the voltage detector 35 as shown in FIG. 5. The time T1' is shorter than the time T1 of the first embodiment. Therefore, in the case of the second embodiment, the period of time required before the stepping motor 21 begins to rotate is shorter than the first embodiment. In this instance, however, the detection voltage VM1' must be set at a value which is sufficiently large for driving the stepping motor 21 to rotate. If the detection time T1' comes to exceed the detection time Tx, the flow of operation proceeds to the step S37 for error processing according to the result of check made at the step S35. Further, in this instance, the voltage VB of the battery 5 is considered to be somewhat lower than in the case of the first embodiment at the start of motor driving after a drop in the battery voltage VB because of a shorter time allowed for voltage recovery during the time T1'. When the motor driving voltage VM changes from the voltage value VM1 to the voltage value VM2, the motor driving voltage VM is at first changed to the lowest motor driving voltage value VM0, and the stop phase is adjusted by a strong exciting action in the same manner as in the case of the first embodiment. After that, the stop phase is weakly excited until the motor driving voltage VM reaches the detection voltage VM2' set at the voltage detector 35. In a case where the motor driving voltage VM changes from the voltage value VM1 to the voltage value VM2, the period of time of the weak exciting action is determined by a period of time T2' required before the motor driving voltage VM reaches the detection voltage VM2' set at the voltage detector 35. This period of time T2' is shorter than the corresponding period of time T2 of the first embodiment. In the case of the second embodiment, the period of time required before the stepping motor 21 comes to rotate is thus shortened. However, since the period of time allowed for the recovery of the battery voltage VB becomes shorter, the battery voltage VB drops to a little greater degree in the case of the second embodiment than in the case of the first embodiment. As described above, the second embodiment is not only capable of giving about the same advantageous effect as the first embodiment but also is capable of shortening the whole operation time by virtue of the arrangement that permits the motor driving voltage changing time to be set at an optimum value as desired. Third Embodiment The following describes a third embodiment of the invention. The arrangement of the third embodiment is similar to that of the first embodiment described in the foregoing and is, therefore, omitted from description. The following description is thus limited to the functions of the third embodiment. In each of the first and second embodiments described in the foregoing, the stop phase of the motor is adjusted by shifting the motor driving voltage VM to its lowest value VM0. However, this invention is not limited to this arrangement. In cases where the motor driving voltage VM is stepwise divided into several values, the strong stop-phase exciting action does not have to be always performed at the lowest level of the motor driving voltage VM. The stop-phase exciting action may be arranged to be performed at a motor driving voltage value which is only one step lower than a voltage value at which the motor is to be driven next time. FIG. 7 shows a relation obtained by the third embodiment between the motor driving voltage value and the exciting action. Referring to FIG. 7, the motor driving voltage VM does not have to be changed from the voltage value VM1 to the voltage value VM2 during a period of time T3 which is provided for strongly exciting the stop phase of the motor, because: The motor driving voltage value VM0 differs to a much less degree from the motor driving voltage VM1 than in the case of the time T0 shown in FIG. 2. The third embodiment is, therefore, arranged to strongly excite the stop phase at the motor driving voltage value VM1. With the third embodiment arranged as mentioned above, although the battery voltage drops once for phase adjustment, a load of waiting time is lessened to enable the battery voltage to recover. This allows the stepping motor to begin to rotate after the recovery of the battery voltage. The battery voltage, therefore, can be prevented from continuously dropping. In accordance with this invention, as described in the foregoing, the battery voltage can be prevented from dropping to an excessive degree. The motor driving voltage also can be prevented from being lowered by the drop of battery voltage. The invented arrangement, therefore, ensures a longer life of the battery in use.	A voltage control device for controlling a driving voltage applied to a motor having a plurality of phases is provided with a switching circuit for changing the motor driving voltage from one voltage value over to another among a plurality of voltage values. The switching circuit is arranged to have a stop phase of the motor excited by a lower driving voltage than a rotation driving voltage in adjusting the stop phase at which the motor has been stopped.	7
FIELD OF THE INVENTION The invention relates to the inspection of insulated objects, more specifically to inspection ports that provide permanent access through a layer of insulation. BACKGROUND OF THE INVENTION Periodic inspection of process equipment such as reactors, heat exchangers, distillation towers, storage tanks, and pipelines is typically performed to measure the effects of corrosion or erosion using non-destructive test methods. The inspection process is more difficult for insulated equipment and typically requires numerous inspection ports cut through the insulation material and any metal jacket at locations most susceptible to corrosion and erosion. Depending on the equipment and the insulation material, inspection ports range from open holes in the insulation material and metal jackets to access plates that are fastened over a hole in the metal jacket to contain a removable section of insulation. U.S. Pat. No. 5,014,866 describes an inspection port which includes an elastomeric, flanged tube and a metal, flanged cap for sealing a hole in a metal jacket containing a layer of insulation around process equipment. The elastomeric tube has a cylindrical body that has a relaxed outside diameter larger than the hole in the metal jacket in order to grip the jacket. The metal cap fits tightly within the elastomeric tube and assists in sealing the tube within the hole in the metal jacket. The tube has a length sufficient to contact the edges of holes through flat or corrugated metals. Both the tube and the cap are flanged to prevent over insertion and the flange of the cap is sized to protect the flange of the tube. Inspections are conducted by removing the cap and any exposed insulation. However, the tube frequently falls out after the cap is removed, especially when installed in corrugated metal jackets. SUMMARY OF THE INVENTION The present invention is an inspection port that is self-locking and self-sealing when inserted in smooth, embossed, or corrugated metal jackets which contain an insulation layer around process equipment such as reactors, heat exchangers, distillation towers, storage tanks, and pipelines. The inspection port is made from an elastomeric material and includes a tubular body having an outer flange and two locking ridges which are positioned to form a short section for gripping non-corrugated metal and a long section for gripping corrugated metal. The inspection port can be used with a metal or elastomeric polymer cap which is securely attached to the inspection port. An optional extension tube can be inserted into the inspection port to retain insulation. BRIEF DESCRIPTION OF THE DRAWINGS So that the manner in which the above recited features, advantages and objects of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. FIGS. 1 and 2 are isometric and side views of an inspection port of the present invention showing a tubular body having an outer flange formed on one end, the tubular body having two locking ridges on a cylindrical outer surface of the tubular body; FIG. 3 shows the inspection port of FIGS. 1 and 2 and an optional extension tube inserted into a non-corrugated metal jacket containing an insulation material around a surface to be inspected; FIG. 4 shows the inspection port of FIGS. 1 and 2 and an optional extension tube inserted into a corrugated metal jacket containing an insulation material around a surface to be inspected; FIGS. 5 and 6 show isometric and sectional views of the inspection port of FIGS. 1 and 2 along with a metal cap inserted into the tubular body and securely attached to the outer flange of the tubular body; and FIGS. 7 and 8 show isometric and sectional views of the inspection port of FIGS. 1 and 2 along with an elastomeric cap inserted into the tubular body and securely attached to the outer flange of the tubular body. DETAILED DESCRIPTION OF THE INVENTION The invention is a self-locking, self-sealing inspection port for insertion into a hole in a metal jacket which contains an insulation material next to a surface to be inspected using non-destructive test methods such as ultrasound. The surface can be a wall of a reactor, heat exchanger, distillation tower, storage tank, pipeline, or other unit having an insulation layer. The inspection port is self-sealing because it is made from an elastomeric polymer and is sized to fit snugly into a hole in the metal jacket. The inspection port can be cylindrical or rectangular, preferably cylindrical. The inspection port is self-locking because it has at least two locking ridges formed on an outer surface for holding the port in the hole in the metal jacket. Referring to a preferred embodiment shown in FIGS. 1-8, an inspection port 10 has a tubular body 12 and an outer flange 14 both preferably formed of an elastomeric polymer having excellent resistance to low and high temperatures such as a silicone rubber or a terpolymer of ethylene, propylene, and diene monomers (EPDM). The tubular body 12 has a first inner cylindrical surface 16 and a second inner cylindrical surface 18. The tubular body 12 further has a first locking ridge 20 and a second locking ridge 22 formed of the elastomeric polymer on the outer surface 24 of the tubular member 12. The locking ridges 20 and 22 divide the outer surface 24 of the tubular member 12 into a short cylindrical section 26 and a long cylindrical section 28. The short cylindrical section 26 has a length corresponding to the thickness of a smooth metal jacket 30 for containing an insulation layer 32 next to a wall to be inspected 34 and the long cylindrical section 28 has a length corresponding to the apparent thickness of a corrugated metal jacket 36 for containing an insulation layer 38 next to a wall to be inspected 34. The inspection port 10 is designed for use without additional mechanical or chemical fasteners or sealants, although such materials can be used if desired. Inspection ports have been made as shown in the drawings from a silicone rubber having a temperature resistance from minus 130° F. to 500° F. and from an EPDM polymer having a temperature resistance from minus 67° F. to 340° F. The EPDM rubber has significantly higher tensile strength and elongation than the silicone rubber and both have excellent UV and ozone resistance. The inspection port 10 can be used with a metal cap 40 having an outer flange 42 or a polymer cap 44 having an outer flange 46. The metal cap 40 or polymer cap 44 fit snugly into the first inner cylindrical surface 16 of the tubular body 12. The caps 40 and 44 are attached to the outer flange 14 of the tubular body 12 by a lanyard 48 as shown in FIGS. 5 and 7, respectively. The lanyard 48 is preferably a braided or twisted cable of small diameter, stainless steel wires. The metal cap 40 or polymer cap 44 fit snugly to form a water-tight seal but are not oversized to expand the tubular body 12. The inspection port 10 has the second inner cylindrical surface 18 in the tubular body 12 for receiving an optional metal extension tube 50. The second cylindrical inner surface 18 has a larger diameter than the first cylindrical inner surface 16 so that the extension tube 50 will have an inside surface 52 that is flush with the first cylindrical inner surface 16 to limit insertion of the extension tube 50. The extension tube 50 extends into the insulation material 32 or 38 as far as the wall to be inspected 34 or any desired distance. The extension tube 50 keeps the insulation material in place if the insulation is not a solid layer. Insulation material may be placed inside the extension tube 50 when the inspection port 10 is capped and may be any suitable insulation material, preferably a cylinder of a solid material. The extension tube 50 thus isolates the test operator from the insulation material 32 or 38 below the metal jacket 30 or 36. The metal cap 40 includes a handle 54 formed of bent metal and attached to the outer flange 52 by mechanical means, which may include but are not limited to, riveting or resistance welding. The lanyard 48 is looped around the handle 54 and through a tab 56 on the outer flange 14 of the inspection port 10. For the polymer cap 44, the lanyard 48 is looped through a tab 58 on the outer flange 46 of the polymer cap 44 and the tab 56 on the outer flange 14 of the inspection port 10. The inspection port 10 is readily installed by drilling a hole in a non-corrugated metal jacket 30 or a corrugated metal jacket 36 and removing the underlying insulation material 32 or 38. The inspection port 10 is then inserted to position a non-corrugated jacket 30 between the outer flange 14 and the first locking ridge 20 or to position a corrugated jacket 36 between the first locking ridge 20 and the second locking ridge 22. When used, the extension tube 50 must be inserted into the tubular body 12 prior to insertion of the inspection port 10 in the metal jacket 30 or 36. The inspection port 10 can be inserted with or without the cap 40 or 44 in place and is most conveniently inserted with the cap removed. Inspections are readily conducted by removing the cap 40 or 44 and any insulation material placed back in the hole in the jacket or within the extension tube 50. The lanyard 48 prevents loss of the cap 40 or 44 prior to re-insertion after inspection. The invention has been described by reference to specific embodiments which teach and support a broader concept of the invention as defined by the following claims. While the foregoing is directed to the preferred embodiment of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims which follow.	The present invention is an inspection port that is self-locking and self-sealing when inserted in smooth, embossed, or corrugated metal jackets which contain an insulation layer around process equipment such as reactors, heat exchangers, distillation towers, storage tanks, and pipelines. The inspection port is made from an elastomeric material and includes a tubular body having an outer flange and two locking ridges which are positioned to form a short section for gripping non-corrugated metal and a long section for gripping corrugated metal.	1
BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a connecting arrangement comprising end sections of two fluid conduits to be connected to one another and comprising a coupling element having an outer side extending about an axis and an inner side extending about the axis. First securing ribs extend in the circumferential direction about the circumference of the end sections; second securing ribs extend in the circumferential direction on the inner side of the coupling element in the vicinity of each axial end of the coupling element. The coupling element is coaxially coupled by being elastically widened to the end sections and one end section is seal-tightly coupled coaxially to the other end section, wherein the second securing ribs are locked behind the first securing ribs in the coupled position. 2. Description of the Related Art In a connecting arrangement of this kind disclosed in European patent application 1 378 701 A1, the coupling element is made from an elastic plastic material and is comprised of two oval rings connected to one another by two diametrically opposed stays. The rings are provided internally with securing ribs in the form of locking noses. Upon insertion of the end sections of the fluid conduits into the rings, the rings are elastically widened by means of the securing ribs provided on the end sections until the locking noses of the rings lock behind the securing ribs of the end sections. In the coupled state, there is play between the ring areas having the smaller radius of curvature and the end sections; the play enables radial compression of the rings for decoupling. Because of the wide intermediate spaces between the stays and the play for decoupling between the rings and the end sections, there is the risk that the end sections of the fluid conduits inserted into the coupling element become soiled. This can cause difficulties for repeated coupling and decoupling. Moreover, there is the risk that the connection will become detached when transverse forces in opposite directions are exerted onto the end sections. SUMMARY OF THE INVENTION It is an object of the present invention to provide a connecting arrangement of the aforementioned kind that prevents the risk of soiling of the connecting location of the end sections and also prevents accidental decoupling. In accordance with the present invention, this is achieved in that the coupling element is a circumferentially closed circular cylindrical sleeve. With this configuration, the sleeve provides an additional sealing action of the connecting location of the end sections in regard to soiling as well as for additional reinforcement of this connecting location in regard to transverse forces. Preferably, it is provided that the sleeve has bending-resistant sleeve segments that extend about at least 80° and less than 180° in the circumferential direction and have neighboring edges that are connected, respectively, by elastic sleeve segments comprising elastically expandable material by being fused thereto or by forming a monolithic part. The bending-resistant sleeve segments contribute an additional reinforcement of the sleeve and thus of the connecting location of the end sections. The elastic sleeve segments can overlap the bending-resistant sleeve segments in their circumferential direction with lateral projections, and the projections can be connected by fusing to the bending-resistant sleeve segments. These projections increase the stiffness or strength of the connection between the sleeve segments and enhance grip of the sleeve when handling the sleeve. On the inner side of the sleeve, a stop rib providing an insertion limitation for the end sections can be arranged circumferentially; one end section rests against the stop rib with its free end and the other end section has a shoulder that rests against the stop rib. The stop rib increases additionally the transverse stiffness of the sleeve and contributes also to the seal-tightness at the connecting location. Preferably, the stop rib is comprised of rib segments that are formed as monolithic parts of the bending-resistant sleeve segments and monolithic parts of the elastic sleeve segments. At least the rib segments that are monolithic parts of the elastic sleeve segments increase as a result of their elasticity the seal-tightness of the connection. When the stop rib comprises an elastically expandable material and forms a monolithic part of the elastic sleeve segments, the stop rib increases the seal-tightness of the connection about its entire circumference. The bending-stiff sleeve segments can have recesses in their exterior side in which recesses an elastically expandable material is embedded. The elastic material embedded in the recesses enhances additionally grip on the sleeve when handling the sleeve. Also, it can be provided that the stop rib comprising an elastically expandable material is monolithically connected to the elastically expandable material in the recesses through openings provided in the bending-stiff sleeve segments. In this configuration, the stop rib and the elastic expandable material in the recesses can be produced in a single injection molding process. Alternatively, it can be provided that the sleeve is a monolithic part made from hard rubber or a reinforced and/or crosslinked elastomer. The sleeve can then also be produced in a single injection molding process and is elastic as well as sufficiently bending-resistant. Instead, it is also possible that the sleeve, including the second securing ribs, comprises an elastically expandable material, that the second securing ribs are spaced apart in the circumferential direction, and that, about the circumferential area of the second securing ribs, cylinder parts made from metal or hard-elastic plastic material and having at their circumferential edges radially inwardly projecting legs are embedded in the elastically expandable material of the sleeve in such a way that the legs project into the second securing ribs. In this configuration of the sleeve, in the area of the cylinder parts comprised of metal or hard-elastic plastic material there are also bending-resistant sleeve segments and between them there are elastic sleeve segments that enable widening of the sleeve for coupling and decoupling the end sections. In the last embodiment it can also be provided that on the inner side of the sleeve a stop rib for insertion limitation of the end sections extends circumferentially wherein the stop rib comprises the elastically expandable material of the sleeve. The stop rib is then suitable also at the same time for sealing the connecting location of the end sections. The second securing ribs of the sleeve can extend about at least 80 E and less than 180 E of the sleeve circumference. Moreover, behind the first securing ribs grooves can be provided in the circumferential direction of the end sections; the axial width of the grooves corresponds to the axial width of the first securing ribs. These grooves enable an insertion limitation of the end sections even when the sleeve has no stop rip and the end section onto which the other end section is pushed when coupling the end section has no stop shoulder. Also, the sleeve can be pre-mounted on one of the end sections in a non-slidable and captive way. Preferably, it is also provided that behind one of the first securing ribs of one end section on its end facing away from the end of this end section inserted into the sleeve two radially projecting cams are provided diametrically opposite one another relative to the longitudinal center axis of this end section, wherein the two cams project by a radial height that matches a radial height of said first securing rib. These cams enable removal of the end section provided with the cams by manually rotating the sleeve until the securing ribs of this end section of the sleeve are seated on the cams and subsequently pulling this end section out of the sleeve. In this connection, the first securing ribs should extend about the entire circumference of the end sections. BRIEF DESCRIPTION OF THE DRAWING In the drawing: FIG. 1 is a perspective illustration of an embodiment of a connecting arrangement according to the invention in axial section in the coupled state; FIG. 2 shows the connecting arrangement according to FIG. 1 in the decoupled state; FIG. 3 is a modification of a sleeve of the connecting arrangement according to FIG. 1 in a perspective illustration; FIG. 4 a side view of the sleeve according to FIG. 3 on a smaller scale; FIG. 5 shows the section V-V of FIG. 4 ; FIG. 6 shows the section VI-VI of FIG. 5 ; FIG. 7 shows the section VII-VII of FIG. 5 ; FIG. 8 is a perspective illustration of another modification of the sleeve according to FIG. 1 ; FIG. 9 is a side view of the sleeve according to FIG. 8 on a smaller scale; FIG. 10 shows the section X-X of FIG. 9 ; FIG. 11 shows the section XI-XI of FIG. 10 ; FIG. 12 is another side view of the sleeve according to FIG. 8 ; FIG. 13 is a perspective view of another modification of the sleeve according to FIG. 1 ; FIG. 14 is an axial view of the sleeve according to FIG. 13 ; FIG. 15 shows the section XV-XV of FIG. 14 ; FIG. 16 shows the section XVI-XVI of FIG. 14 ; FIG. 17 is a perspective view of another modification of sleeve according to FIG. 1 ; FIG. 18 is a side view of the sleeve according to FIG. 17 on a smaller scale; and FIG. 19 shows the section IXX-IXX of FIG. 18 . DESCRIPTION OF THE PREFERRED EMBODIMENTS The connecting arrangement according to FIG. 1 and FIG. 2 is comprised of two fluid conduits 1 and 2 (the illustrated embodiment shows conduits in the form of hoses) with end sections 3 and 4 ; two union nuts 5 , 6 connecting the fluid conduits 1 , 2 with one of the end sections 3 , 4 , respectively; a coupling element in the form of a circumferentially closed circular cylindrical sleeve 7 ; and a sealing ring 8 . All parts are comprised of plastic material. However, the end sections 3 , 4 and the union nuts 5 , 6 can also be made from metal. Instead of connecting the end sections 3 , 4 and the fluid conduits 1 , 2 to one another by union nuts 5 , 6 , these parts can also be configured as monolithic parts made of plastic material. Moreover, at least one of the two end sections 3 , 4 can be a pipe socket, for example, the pipe socket connector of a radiator of a motor vehicle that is then connected to a cooling water line in the form of a cooling coil in the interior of the radiator. In this case, the corresponding end section would however be made from metal. The sleeve 7 is comprised of two sleeve segments that are diametrically opposed to one another relative to the longitudinal axis of the sleeve and made from hard-elastic thermoplastic material, for example, one of the plastic materials polypropylene (PP), polyethylene (PE), polyamide (PA), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polybutylene naphthalate (PBN), polyethylene naphthalate (PEN), polyoxymethylene (POM), polyethylene sulfide (PPS), polyphenylene amide (PPA), and thermosetting plastic material so that the sleeve segments 9 are bending-resistant. Inserts 10 of elastomer material are injection-molded into the outer side of the sleeve segments 9 . The inserts 10 are provided with recesses 11 in order to enhance grip on the sleeve 7 . However, the inserts are not mandatory. Instead, the sleeve segments 9 can be corrugated on the outer side. Between the sleeve segments 9 and the inserts 10 , elastic sleeve segments 12 made from thermoplastic elastically expandable material can be injection-molded onto the sleeve segments 9 and their inserts 10 so that the sleeve segments 9 and their inserts 10 are connected to the sleeve segments 12 by being fused thereto and the sleeve 7 can be radially widened. The thermoplastic elastically expandable material of the sleeve segments 12 is, for example, one of the plastic materials of thermoplastic elastomer (TPE), vulcanized thermoplastic elastomer (TPV), thermoplastic polyurethane (TPU), thermoplastic ether ester elastomer (TEEE), ethylene propylene (EPDM), fluorinated rubber (FKM), fluorosilicone, liquid silicone rubber (LSR), and ethylene vinyl acetate (EVA). The sleeve segments 9 extend therefore across a circumferential are of the sleeve 7 of less than 180° but more than 80°, preferably about an area of approximately 140° and 160°. The bending-resistant sleeve segments 9 are provided on their inner side in the vicinity of their ends with securing ribs 13 extending in the circumferential direction and provided on their circumferential ends with slanted flanks 14 ( FIG. 2 ). The elastic sleeve segments 12 are provided externally with an axially extending projection 15 that has centrally a circular arc shaped double arrow 16 indicating the rotatability of the sleeve 7 . The interior of the sleeve 7 at its axial center is provided with a circumferentially extending stop rib 17 ( FIG. 1 ) whose segments are identified in the area of the elastic sleeve segments 12 by reference numeral 17 a and in the area of the hard-elastic sleeve segments 9 by reference numeral 17 b . The stop rib segments 17 a are comprised therefore of the same material as the elastic sleeve segments 12 and the stop rib segments 17 b are comprised of the same material as the hard-elastic sleeve segments 9 . The end sections 3 , 4 are provided with circumferentially extending securing ribs 18 about their circumference. For connecting the fluid conduits 1 , 2 , the end sections 3 , 4 are inserted axially into the sleeve 7 and coupled after the sealing ring 8 has been inserted into an annular groove of the end section 3 that is inserted into the end section 4 . Upon insertion of the end sections 3 , 4 into the sleeve 7 in a predetermined relative angular position relative to the end section 4 , the sleeve 7 is radially elastically widened as the securing ribs 13 of the sleeve 7 pass across the securing ribs 18 of the end sections 3 , 4 until the securing ribs 13 of the sleeve 7 lock behind the securing ribs 18 of the end sections 3 , 4 in a groove 19 or 20 adjoining the securing ribs 18 and extending in the circumferentially direction, respectively. At the same time, the end sections 3 , 4 come to rest against the stop rib 17 . In order to enable contact of the end section 3 at the stop rib 17 , the end section 3 is provided with a shoulder 21 . The groove 19 in the end section 3 is a circumferential annular groove. In contrast, the groove 20 in the end section 4 does not extend completely about the circumference but is interrupted by two cams 22 that project by a radial height matching the radial height of the securing rib 18 of the end section 4 . The two cams 22 are positioned diametrically opposed to one another relative to the longitudinal center axis of the end section 4 and are provided with slanted flanks. The axial width of the securing ribs 13 of the sleeve 7 corresponds to the axial width of the grooves 19 and 20 . Upon insertion of the end sections 3 , 4 into the sleeve 7 , the securing ribs 13 of the sleeve 7 can therefore also contact the flanges 23 , 24 delimiting the grooves 19 and 20 of the end sections 3 , 4 , respectively. In the coupled state of the connecting arrangement according to FIG. 1 , the sleeve segments 12 rest with their ends against the cams 23 . For releasing the connection, the sleeve 7 is rotated. When doing so, the securing ribs 13 move with their slanted flanks 14 onto correspondingly slanted flanks of the cams 22 at one end of the bending-resistant sleeve segments 9 and widen the sleeve 7 . In this rotational angle position, the sleeve 7 together with the end section 3 and the flexible fluid conduit 1 can be removed from the end section 4 . The sleeve 7 can also be pre-mounted on the end section 3 in the position illustrated in FIG. 1 and, finally, can be coupled with the end section 4 and the fluid conduit 2 connected thereto in an angular position in which the elastic sleeve segments 12 are aligned with the cams 25 in order to connect the fluid conduits 1 , 2 with one another. The stop rib 17 not only provides a limitation for the insertion depth of the end sections 3 , 4 into the sleeve 7 but also a sealing action at the connecting location of the end sections 3 , 4 in addition to the sealing action of the sealing ring 8 . The flanges 23 , 24 are provided with ribs so that they provide enhanced grip in order to be able to hold the end sections 3 , 4 safely when rotating the sleeve 7 . FIGS. 3 to 7 represent a sleeve 27 that is modified somewhat relative to the sleeve 7 according to FIG. 1 and FIG. 2 . The parts of the sleeve 27 that resemble those of the sleeve 7 are identified by reference numerals increased by 20 relative to the corresponding parts of the sleeve 7 ; the same parts have the same reference numerals. A circumferentially extending stop rib 37 of the same thermoplastic elastic material as that used for the elastic sleeve segments 32 is injection-molded onto the inner side of the bending-resistant sleeve segments 9 and the elastic sleeve segments 32 . At the same time, the elastic material of the stop rib 37 is injection-molded through openings 30 provided in the bending-resistant sleeve segments 29 into recesses 31 provided in the bending-resistant sleeve segments 29 so that the exterior side of the sleeve segments 29 provide grip-enhancing surfaces 23 for facilitating manual rotation of the sleeve 27 . The circumferentially extending elastic stop rib 37 has the advantage that it better seals the connecting location of the end sections 3 , 4 than the sections of the stop rib 17 provided in the area of the bending resistant sleeve segments 9 of the sleeve 7 and made of the same harder material as the sleeve segments 9 ; the stop rib 17 is comprised only in the area of the elastic sleeve segments 12 of the same elastic material as the sleeve segments 12 . FIGS. 8 to 12 show a sleeve 47 that is another modification of the sleeve 7 according to FIGS. 1 and 2 . The parts of the sleeve 47 that resemble those of the sleeve 7 are identified by reference numerals increased by 30 relative to the corresponding parts of sleeve 7 ; the same parts have the same reference numerals. In deviation from the sleeve 7 according to FIGS. 1 and 2 , the elastic sleeve segments 42 are provided with lateral projections 43 that are injection-molded into recesses of the hard-elastic sleeve segments 39 and are fused to the sleeve segments 39 . The projections 43 increase the strength of the connection of the elastic sleeve segments 42 with the hard-elastic sleeve segments 39 . The projection 15 of elastic sleeve segments 12 of the sleeve 7 according to FIGS. 1 and 2 has been omitted because the elastic material of the sleeve segments 42 can be selected such that it enhances grip sufficiently. For example, silicone rubber can be used. In FIGS. 13 to 16 a sleeve 57 modified relative to sleeve 7 according to FIG. 1 and FIG. 2 is illustrated. The parts of the sleeve 57 that resemble those of the sleeve 7 are identified by reference numerals increased by 50 relative to the corresponding parts of sleeve 7 ; the same parts have the same reference numerals. Sleeve 57 is comprised about its entire circumference of a monolithic part of hard-elastic material, for example, hard rubber or reinforced and/or vulcanized thermoplastic elastomer. The securing ribs 18 of the sleeve segments 9 (the latter are monolithic parts of the sleeve segments 12 ) extends across approximately 80 E to 100 E in the circumferentially direction of the sleeve 57 , preferably about approximately 90 E. Accordingly, the sleeve segments 9 are less elastically expandable then the thinner sleeve segments 12 so that the sleeve 57 can still be expanded or widened. In addition to the projection 15 , the sleeve 57 is provided with axial ribs 56 that are distributed about the circumference in order to enhance grip on the sleeve 57 . FIGS. 17 to 19 represent another sleeve 67 as a modification of the sleeve 7 according to FIG. 1 and FIG. 2 . The parts of the sleeve 67 that resemble those of the sleeve 7 are identified by reference numerals increased by 60 relative to the corresponding parts of sleeve 7 ; the same parts have the same reference numerals. The sleeve 67 , including its securing ribs 13 and stop rib 17 has about its entire circumference the same elastically expandable material as the sleeve segments 12 of the sleeve 7 according to FIGS. 1 and 2 . In the circumferential area of the securing ribs 13 , however, a cylindrical part 68 made of metal or the same hard-elastic plastic material as the sleeve segments 9 according to FIG. 1 and FIG. 2 is embedded. The cylinder parts 68 have at their circumferential edges inwardly projecting legs 69 that project into the securing rib 73 . The legs 69 can also be interrupted in the circumferential direction. While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.	A connecting arrangement has end sections of two fluid conduits to be connected to one another and a coupling element having an axis and an outer side surrounding the axis and an inner side surrounding the axis. On the circumference of the end sections first securing ribs extend in the circumferential direction. On the inner side of the coupling element second securing ribs extending in the circumferential direction are provided proximal to each axial end of the coupling element. The coupling element is coaxially coupled to the end sections in the coupled state of the connecting arrangement by being elastically expanded, wherein the second securing ribs lock behind the first securing ribs and the end sections are coupled seal-tightly with one another. The coupling element is a circular cylindrical sleeve that is closed circumferentially.	5
FIELD OF THE INVENTION The invention relates to improved wind turbine control methods and systems and in particular to improved wind turbine control methods and systems for limiting over speeds due to wind gusts. BACKGROUND The damaging effects of wind gusts in wind turbines are well known in the art. If the wind speed increases in a small interval of time the generator speed may exceed its allowed limits because the WT controller is not able to generate a fast enough reaction, and this can cause potential damaging effects for the generator and other wind turbine components. In the case of an extreme operating gust which also produces extreme loads on main structural components such as the blade root and the tower bottom a typical solution is shutting down the wind turbine. In this respect WO 2004/077068 describes the use of lidar means for detecting gusts well before the wind change reaches the turbine tower so that the blades could be feathered using the pitch control means. A known approach for coping with wind gusts is using the generator torque control means for avoiding over-speed problems. However this technique involves risks of causing huge loads in several wind turbine components. Another approach disclosed for example in U.S. Pat. No. 7,342,323 is based in sensing the wind speed at a desired distance from the wind turbine generator and controlling the pitch of the blades of the wind turbine using said “advanced” information of the wind speed. However the complexity and the lack of robustness of this technique raise reliability problems. WO 2007/138138 in the name of the applicant discloses a solution for an extreme operating gust that keeps the wind turbine in operation and minimizes the bending moments carrying out a sudden increase of the pitch angle by saturating the minimum pitch rate value when the extreme operating gust is detected. This technique is applicable to a very particular case of wind gust. The present invention focuses on finding a solution for these drawbacks. SUMMARY OF THE INVENTION It is an object of the present invention to provide reliable wind turbine control methods and systems for limiting over speeds due to wind gusts. It is another object of the present invention to provide wind turbine control methods and systems for limiting over speeds due to wind gusts able to react quickly to them without a wind speed measure in advanced and keeping the windturbine producing. In one aspect these and another objects are met by a method for the operation of a variable speed wind turbine having pitch and torque control means that include additional steps for providing to the pitch control means in case of a wind gust a pitch angle reference increment Δθ ref in the amount needed for avoiding that the aerodynamic torque added by the wind gust exceeds a predetermined limit and increases the rotor speed and so the generator speed. In embodiments of the present invention said pitch angle reference increment Δθ ref is provided/removed to/from the pitch control means depending on the value of a switch indicating the presence/absence of a wind gust depending on at least the values of the generator acceleration A and the generator speed Ω. Therefore the method includes separated steps for calculating the pitch angle reference increment Δθ ref needed for counteracting an aerodynamic torque excess due to a “possible” wind gust and for detecting the presence/absence of a wind gust according to predefined conditions of generator acceleration and generator velocity (and even an additional user-defined condition) so that said the calculated pitch angle reference increment Δθ ref is only applied when said switch is On. This allows on one side a fast reaction to wind gusts and on the other side avoids unnecessary reactions in certain wind turbulent conditions. In embodiments of the present invention said pitch angle reference increment Δθ ref is determined as a function of at least the aerodynamic torque excess T exc due to the wind gust (the product of the generator acceleration and the total moment of inertia) and the torque sensitivity to the pitch angle T sens (calculated from a given table obtained from static simulation because it is a variable depending on many physical features of the wind turbine). Therefore the pitching action for reacting to wind gusts is made dependant not only on a wind gust depending variable (the generator acceleration) but also on physical features of the wind turbine so that a more controlled reaction to wind gusts can be achieved. In embodiments of the present invention said pitch angle reference increment Δθ ref is also determined taking into account the expected generator speed increment ΔΩ due to the wind gust and the closeness of the generator speed Ω to a predetermined threshold value. Therefore additional variables are used for controlling the pitching action reaction to those wind gusts that can lead the wind turbine close to its operating limits. In another aspect, the above mentioned objects are met by a wind turbine comprising: a tower and a nacelle housing, a generator driven by a wind rotor formed by a rotor hub and one or more blades; measuring devices of at least the generator speed Ω and the pitch angle θ of each blade; a control system connected to said measuring devices and to at least pitch and torque control actuators, the control system being arranged for performing a regulation of the wind turbine according to a predetermined power curve for wind speeds below the cut-out wind speed V out ; the control system being also arranged for performing an additional regulation for wind gusts events providing to the pitch control means a pitch angle reference increment Δθ ref in the amount needed for avoiding that the aerodynamic torque added by a wind gust exceeds a predetermined limit, said additional regulation being enabled when a wind gust according to predefined conditions takes place and disabled when said wind gust ends. In embodiments of the present invention the control system arrangement for performing said additional regulation comprises a module for obtaining said pitch angle reference increment Δθ ref and a switch Sw for enabling/disabling said additional regulation having: a first sub-module for calculating the generator acceleration A and the generator acceleration reference A ref depending respectively on the filtered generator speed Ω and the generator speed reference Ω ref used by the wind turbine pitch control means; a second sub-module for calculating the excess of aerodynamic torque T exc added by the wind gust and the required pitch angle reference increment Δθ req to overcome said excess depending on at least the mean value of the measured pitch angles θ mean and the wind turbine inertia; a third sub-module for calculating the expected generator speed increment ΔΩ assuming that the blades will pitch at the maximum allowable speed; a fourth sub-module for calculating a weighting factor G to be applied to the required pitch angle reference increment Δθ req depending on the expected generator speed increment ΔΩ and the closeness of the generator speed Ω to a threshold value; a fifth sub-module for calculating the enabling/disabling switch depending on at least the generator speed Ω and the generator acceleration A; a sixth sub-module for calculating the pitch angle reference increment Δθ ref to be provided to the pitch control means. Therefore the implementation of the additional regulation according to the present invention is done using, on the one side, available signals at the wind turbine control system and, on the other side, dependant variables of said signals easy to obtain and configuration parameters regarding relevant physical features of the wind turbine. This allows a simple and robust implementation of said additional regulation. Other features and advantages of the present invention will be understood from the following detailed description of illustrative and by no means limiting embodiments of its object in relation with the enclosed drawings. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic section side view of a wind turbine. FIG. 2 shows a typical power curve of a wind turbine. FIG. 3 is a schematic block diagram of the additional regulation according to the present invention. FIGS. 4-9 are detailed block diagrams of an embodiment of the additional regulation according to the present invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS A typical wind turbine 11 comprises a tower 13 supporting a nacelle 21 housing a generator 19 for converting the rotational energy of the wind turbine rotor into electrical energy. The wind turbine rotor comprises a rotor hub 15 and, typically, three blades 17 . The rotor hub 15 is connected either directly or through a gearbox to the generator 19 of the wind turbine for transferring the torque generated by the rotor 15 to the generator 19 and increase the shaft speed in order to achieve a suitable rotational speed of the generator rotor. The wind turbine power output is typically controlled by means of a control system for regulating the pitch angle of the rotor blades and the generator torque. The rotor rotational speed and power output of the wind turbine can hereby be initially controlled. Below the cut-out wind speed V out the wind turbine control system is arranged to regulate the power production according to a curve which defines the desired functional relationship between power and speed to achieve ideal output. A curve of this type is curve 25 in FIG. 2 showing that the power production P increases from a minimum wind speed V min to the nominal wind speed V n and then remain constant in the nominal power value P n up to the cut-out wind speed V out where decreases up to 0. For implementing said regulation a control unit receives input data such as wind speed V, generator speed Ω, pitch angle θ, power P from well known measuring devices and send output data θ ref , T ref to, respectively, the pitch actuator system for changing the angular position of the blades 17 and to a generator command unit for changing the reference for the power production. According to the present invention the control system is also arranged for performing an additional regulation in case of wind gusts (i.e. a regulation that is enabled when a wind gust is detected and that is disabled when the wind gust ends) that increases the pitch angle reference θ ref to be provided to the pitch actuator of the blades in the amount needed for avoiding that the aerodynamic torque added by the wind gust exceeds a predetermined limit. As shown in FIG. 3 the basic inputs to the control unit 31 that implements said additional regulation are the following ones: the generator speed Ω, the filtered generator speed Ω fil used in the pitch controller, the generator speed reference Ω ref generated by the pitch controller and the mean pitch angle θ mean (a non filtered mean value of the measured blade pitch angles). The outputs are the increment of the pitch angle reference Δθ ref to be provided to the pitch actuator system and a switch Sw for enabling/disabling the additional pitch angle regulation. Said control unit 31 comprises a module implementing a suitable algorithm for determining the increment of the pitch angle reference Δθ ref in the amount needed for avoiding that the aerodynamic torque added by the wind gust exceeds a predetermined limit. In a preferred embodiment said algorithm is implemented by means of the sub-modules shown in FIGS. 4 to 9 . In the first sub-module shown in FIG. 4 the generator acceleration A is calculated in block 33 as the derivative of the generator speed Ω fil . The generator acceleration reference A ref is also calculated in block 35 as the derivative of the generator speed reference Ω ref . In the second sub-module shown in FIG. 5 the excess of aerodynamic torque T exc and the required pitch angle increment Δθ req for limiting said excess are calculated. The excess of aerodynamic torque T exc is calculated (block 43 ) as the product of the rotor acceleration A rot and the total moment of inertia P 2 . The rotor acceleration A rot is calculated (block 41 ) from the generator acceleration A and the drive train multiplication ratio P 1 . A torque sensitivity T sens for the mean value of the measured pitch angles θ mean is calculated (block 47 ) from a reference sensitivity parameter P 3 and an additional factor (block 45 ) depending of θ mean that corrects the non linear sensitivity of torque to pitch angle. From the excess of aerodynamic torque T exc and the torque sensitivity T sens the required increment of the pitch angle increment Δθ req is derived (block 49 ). This is, then, the necessary pitch increment in order to maintain the current aerodynamic torque. In the third sub-module shown in FIG. 6 the rotor and generator over-speed increments ΔV rot , ΔΩ due to the wind gust are calculated assuming that the blades will pitch at the maximum allowable speed P 4 . Said increments are calculated (blocks 53 , 55 ) from the rotor acceleration A rot and the deceleration derivative imposed by the maximum allowable speed P 4 which value (block 51 ) is directly proportional to the torque sensitivity T sens , to the maximum allowable speed P 4 and inversely proportional to the total moment of inertia of the rotor P 2 . In the fourth sub-module shown in FIG. 7 is calculated a weighting factor G of the required increment of the pitch angle increment Δθ req depending on the expected generator over-speed increment ΔΩ due to the wind gust and to the generator speed Ω closeness to a generator over-speed shut-down threshold P 4 (blocks 61 , 63 , 65 ). The weighting factor G is greater the higher the expected generator over-speed increment ΔΩ is. The weighting factor G is also greater the closer the generator speed Ω is from generator over-speed shut-down threshold P 4 . In the fifth sub-module shown in FIG. 8 is calculated (block 75 ) a switch for enabling/disabling the algorithm in order to limit its actuation. In this respect three conditions are taken into account. The first condition (block 71 ) is that the generator speed Ω is higher than a threshold value P 6 below the rated generator speed value P 5 for enabling the algorithm. The second condition (block 73 ) is that the generator acceleration A is higher than a threshold value P 7 for avoid enabling the algorithm at start-up processes. The generator acceleration reference A ref is also considered. The third condition is a user defined parameter P 8 for enabling/disabling the algorithm. Finally in the sixth sub-module shown in FIG. 8 the pitch angle increment Δθ ref is calculated (block 81 ) applying the weighting factor G and a user defined factor P 9 to the required pitch angle increment Δθ req . If the switch for enabling/disabling the algorithm is On, then the pitch angle increment Δθ ref is provided to the pitch controller (block 83 ). The main distinguishing features of the wind gust regulation according to present invention with respect to the prior art are the following: It only uses measured values of the generator speed Ω and blade pitch angle θ which are reliable signals available at the wind turbine. It does not use wind measures provided by the wind turbine anemometer or by other devices placed in the wind turbine or outside the wind turbine for measuring the wind because they provide delayed measures or measures lacking robustness. It takes into account the wind turbine physics, i.e. the wind turbine aerodynamics and mechanics. Aerodynamic torque received by the wind turbine depends on rotor aerodynamics. Similarly, the wind turbine acceleration and hence the over-speed is inversely proportional to the wind turbine inertia. It allows that the control means can react quickly to wind gusts and keep the wind turbine producing energy in a safe mode. Although the present invention has been fully described in connection with preferred embodiments, it is evident that modifications may be introduced within the scope thereof, not considering this as limited by these embodiments, but by the contents of the following claims.	Improved wind turbine control methods and systems. The invention relates to a method for the operation of a variable speed wind turbine having pitch and torque control means that include additional steps for providing to the pitch control means in case of a wind gust a pitch angle reference increment Dθref in the amount needed for avoiding that the aerodynamic torque added by the wind gust exceeds a predetermined limit. The present invention also relates to a wind turbine comprising a control system arranged for performing an additional regulation in case of wind gust.	5
CROSS REFERENCE TO RELATED APPLICATION This application is a divisional of commonly owned application Ser. No. 09/698,322 filed Oct. 27, 2000 now U.S. Pat. No. 6,543,545, entitled “Expandable Sand-control device and Specialized Completion System and Method,” the disclosure of which is incorporated herein by reference in its entirety. FIELD OF INVENTION The present invention relates to sand-control apparatus and methods in a subterranean hydrocarbon well. More particularly, the present invention relates to methods and apparatus for using an expandable sand control device in conjunction with a specialized gravel pack fluid system. BACKGROUND The control of the movement of sand and gravel into a wellbore and production string has been the subject of much importance in the oil production industry. Gravel pack operations are typically performed in subterranean wells to prevent fine particles of sand or other debris from being produced along with valuable fluids extracted from a geological formation. If produced, the fine sand tends to erode production equipment, clog filters, and present disposal problems. It is therefore economically and environmentally advantageous to ensure that the fine sand is not produced. During gravel packing, the annulus between the well bore wall and the production tubing, which can include a screen or slotted liner assembly, is filled with selected natural or man-made packing material, or “gravel.” Such packing materials can include naturally occurring or man-made materials such as sand, gravel, glass, metal or ceramic beads, sintered bauxite and other packing materials known in the art. The gravel prevents the fine sand from the formation from packing off around the production tubing and screen, and the screen prevents the large grain sand from entering the production tubing. One difficulty in packing operations, especially in open-hole wellbores, is completely filling the often irregular annular space between the production tubing and the wellbore wall. Where packing is incomplete, “voids” are left around the production tubing. These voids, or areas which are incompletely packed with gravel, allow sand fines to be produced along the area of sand screen or slotted liner. The fines can clog the production assembly or erode production equipment. Consequently, a more effective method of packing a wellbore is needed. SUMMARY In general, a method is provided for completing a subterranean wellbore, and an apparatus for using the method. The method comprises positioning an expandable sand-control device in the wellbore thereby forming an annulus between the sand-control device and the wellbore; depositing a filter media in the annulus; and after the depositing step, radially expanding the sand-control device to decrease the volume of the annulus. The sand-control device can be a sand screen or slotted or perforated liner having radially extending passageways in the walls thereof, the passageways designed to substantially prevent movement of the particulate material through the passageways and into the sand-control device. Where a slotted liner is desired, the passageways can be plugged during positioning and later unplugged for production. The filter media is typically a particulate material and can be deposited as a slurry comprising liquid material and particulate material, or as a cement slurry. The step of expanding the sand-control device further includes squeezing at least a portion of the liquid of the slurry through the sand-control device passageways thereby forming a pack in the wellbore annulus. The liquid material can be water-based, oil-based or emulsified and can include gelling agents. Further, the particulate can be resin coated with a delayed form system. The form system can include particulate material. The foam can also include decomposable material which can be decomposed after placement of the form in the annulus. Another embodiment of the method and apparatus presented herein comprises positioning a well-completion device into the wellbore, thereby forming an annulus between the well-completion device and the wellbore, the well-completion device having a flexible, permeable membrane sleeve surrounding an expandable sand-control device; and thereafter radially expanding the sand-control device to decrease the volume of the annulus, thereby also expanding the membrane sleeve. The well-completion device can further include a layer of filter media encased between the membrane sleeve and the sand-control device. The filter media may be of any type known in the industry. Preferably, the membrane sleeve, when expanded, substantially fills the annular space extending between the wellbore and the sand-control device by deforming to substantially contour the wellbore. BRIEF DESCRIPTION OF THE DRAWINGS Drawings of the preferred embodiment of the invention are attached hereto, so that the invention may be better and more fully understood, in which: FIG. 1 is a schematic elevational cross-sectional view of a typical subterranean well and tool string utilizing the invention; FIG. 2 is a schematic elevational detail, in cross-section, of the depositing the filter media and expanding the expandable sand-control device of the invention; FIG. 3 is a detail of a slotted or perforated liner which can be used with the invention; and; FIGS. 4A and 4B are views of alternate embodiments of the invention. Numeral references are employed to designate like parts throughout the various figures of the drawing. Terms such as “left,” “right,” “clockwise,” “counterclockwise,” “horizontal,” “vertical,” “up” and “down” when used in reference to the drawings, generally refer to orientation of the parts in the illustrated embodiment and not necessarily during use. The terms used herein are meant only to refer to the relative positions and/or orientations, for convenience, and are not meant to be understood to be in any manner otherwise limiting. Further, dimensions specified herein are intended to provide examples and should not be considered limiting. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, a tubing string 10 is shown run in well 16 at least to the zone of interest 12 of the formation 14 . The well 16 can be on-shore or offshore, vertical or horizontal, consolidated or unconsolidated and can be cased or an open-hole. It is expected that the invention will be primarily utilized in open-hole horizontal wells, but it is not limited to such use. The tubing string 10 extends from the well surface 18 into the well bore 20 . The well bore 20 extends from the surface 18 into the subterranean formation 14 . The well bore 20 , having well bore wall 26 , extends through a cased portion 22 and into an un-cased open-hole portion 24 which includes the zone of interest 12 which is to be produced. In the cased portion 22 of the well, the well bore 20 is supported by a casing 26 . The well bore typically is cased, as shown, continuously from the well surface but can also be intermittently cased as circumstances require, including casing portions of the wellbore downhole from the zone of interest 12 . The well is illustrated for convenience as vertical, but as explained above, it is anticipated that the invention may be utilized in a horizontal well. The tubing string 10 extends longitudinally into the well bore 20 and through the cased portion 22 . The tubing string can carry packers, tester, circulating and multi-position valves, cross-over assemblies, centralizers and the like to control the flow of fluids through the tubing string and placement of the string in the well bore. Adjacent the lower end 28 of the tubing string 10 a sand control device 30 is connected. The sand control device 30 can be of many types which are generally known in the art, including one or more sand screens. Preferably POROPLUS (a trademark) sand screens are used and reusable, retrievable screens are preferred. Apparatus and methods for constructing and deploying screens are used in conjunction with the invention. Exemplary sand-control screens and methods of deployment are disclosed in U.S. Pat. Nos. 5,931,232 and 5,850,875, and in U.S. Patent Application Ser. No. 09/627,196 filed Jul. 27, 2000, all of which are assigned to the assignee of this application and are incorporated herein by reference for all purposes. The sand control device 30 can also be a slotted or perforated liner or sleeve, such as seen in FIG. 3, and such as are known in the art, having radially extending passageways 31 to fluidly connect the interior of the slotted liner 30 with the formation. In the case of a slotted or perforated liner it may be desirable to plug the passageways 31 in the liner with plugs 33 during run-in of the tools and completion of the packing procedure. The passageways 31 can later be unplugged, or the plugs 33 removed, to allow fluid flow into the tubing string. Removal of the plugs 33 can be accomplished mechanically or chemically as is known in the art. Mounted on the tubing string 10 are a hanger 32 and an open-hole packer 34 . The packers are shown in their expanded or “set” positions. The packers are run into the hole in a retracted or unexpanded condition. The hanger 32 engages the casing 26 of the cased portion 22 of the well and typically provides a seal through which fluids and particulate cannot pass. The hanger 32 can be a retrievable direct hydraulic hanger with a control line access feature 36 . The hanger can be of any type generally known in the art and can be an inflatable, compression or other type of hanger, and can be actuated hydraulically, by wireline or otherwise as will be evident to those of ordinary skill in the art. Similarly, the open-hole packer 34 may be of any type known in the art such as a “hook wall” packer or a non-rotating inflatable packer. The packer can be retrievable if desired. Additional or fewer packers and hangers can be employed without departing from the spirit of the invention. A lower packer 34 may only be necessary when it is desired to seal off a non-producing zone downhole from the zone of interest 12 . The tubing string 10 , as shown in FIG. 1, can additionally carry other drill string tools for controlling and measuring fluid flow and well characteristics and for manipulating the tubing string. Illustrated are a valve 40 , a cross-over kit 42 having a control line 36 , and disconnects 44 . These tools are generally known in the art and additional tools, such as collars, measuring devices, and samplers can be added to the tool string as desired. The tubing string 10 or work string 50 also carries an expansion tool assembly 52 . The expansion tool assembly is run into the well in a retracted position so as not to interfere with movement of the tubing and work strings, as seen in FIG. 1 . The expansion tool is activated to an expanded position 54 , as seen in FIG. 2, and drawn through the expandable sand-control device 30 . The expansion cone, or other expansion device, such as is known in the art, can be hydraulically actuated by a downhole force generator or can be forced along the tubing string by weight applied to the work string. The expansion of the expandable sand-control device can occur from top-down or from bottom-up, as desired. Preferably the expansion tool assembly is retrievable. The tubing string preferably carries centralizers 48 which act to maintain the tubing string in a spaced relation with the well bore wall 26 . This is of particular importance where the well bore is horizontal. The details of construction of the centralizers 48 varies according to the requirements of the application and include segmented “fin” devices, round disks as well as the centralizers shown. The centralizers aid in cuttings removal and protect the expandable sand-control device 30 during run-in and drilling operations, as well. A working string 50 can be deployed interior of the tubing string 10 and sand-control device 30 . Working string 50 can carry a plurality of well tools as are known in the art. Such tools can include a measuring while drilling assembly 62 , a shoe 64 , a downhole motor 66 , a drill bit 68 and a receptacle 70 for the downhole motor and bit, as shown. Preferably these tools are retrievable. Additional tools and types of tools can be utilized as well without departing from the spirit of the invention. Those skilled in the art will recognize a vast choice of tool combinations depending on the requirements of the formation and desires of the practitioner. The measuring while drilling assembly 62 preferably includes a logging while drilling function and may include an acoustic telemetry system to provide real-time data acquisition of well characteristics. Other data acquisition instruments can also be employed. Disconnects 44 allow sections of the tubing and work strings to be released for retrieval to the surface for reuse. Additionally the disconnects can allow portions of the strings, such as downhole motor 66 and drill bit assembly 68 to be retracted into receptacle 70 used for that purpose. Disconnects 44 are of types generally known in the art and may be mechanically, hydraulically or explosively actuated. A tool assembly, such as the one shown in FIGS. 1 and 2, is drilled into place in formation 14 using a downhole motor 66 and drill bit 68 assembly. The tool assembly can include a downhole motor 66 with bit 68 , a measuring while drilling tool assembly 62 , a receptacle housing 70 , an expanding screen or slotted liner device 30 , blank tubing 72 and an expansion tool assembly 52 . Depending on the tool assembly configuration, the expansion tool 52 can be run-in as part of the assembly or on a separate trip. Also depending on the configuration, an inner tubing string, or work string 50 or the tubing string 10 with expandable sand-control device 30 can be used as the fluid conduit during drilling, wellbore fluid and filter media placement. The bottom hole assembly is made up and run in the wellbore 20 . The open-hole portion 24 will be drilled with the downhole motor 66 and drill bit 68 assembly along the desired well bore trajectory and to the desired depth. Once the zone of interest 12 is passed or reached, the wellbore can be cleaned to remove cuttings, as is known in the art. Once cleaned, a wellbore fluid can be placed in the well bore annulus 72 between the tubing string 10 and the well bore wall 26 . The use of well bore fluids is well known in the art. Preferably the hanger 32 is set in the cased portion 22 of the well, as shown. Alternately, a packer may be used. The hanger anchors the sand-control device 30 in place. The work string 50 can be released at disconnect 44 to allow recovery of the measurement while drilling tool 62 and latching of the downhole motor 66 and drill bit 68 assembly into the receptacle housing 70 . The receptacle housing 70 seals the motor 66 from the sand-control device 30 if desired. The recovery of the work string may occur before or after insertion of the filter media 74 into the annulus 72 depending on the system configuration. The filter media 74 is placed across the annulus 72 , particularly along the length of the annulus surrounding the sand-control device 30 . The filter media 72 can be inserted into the annulus 72 by any method known in the art, such as pumping the filter media 74 from the surface 18 through the annulus 76 between the work string 50 and the tubing string 10 and thereafter through ports 80 into annulus 72 . The ports may be located at various places along the tubing string. Alternately, the filter media can be pumped out of the shoe 64 at the lower end of the hole. In such a case, the lower isolation packer 34 would be unnecessary. In cases where the tubing string 10 is run in on a separate trip from the drilling string 30 , the filter media 74 can be pumped into the annulus 72 during running of the tubing string 10 or after the desired depth is reached by the string. Further, the filter media 74 can be pumped in as the welbore fluid is removed. The method and direction of pumping, or inserting, the filter media 74 is not critical to the invention. Various methods of placing the filter media 74 into the annulus 72 will be readily apparent to those of skill in the art. Preferably, the drilling operation, filter pumping operation and sand-control device expansion operation can be accomplished with a single trip of the combined tubing string and concentric work string. However, multiple trips may be necessary or desired depending on the configuration employed. The filter media 74 of the process can take several forms. Some of the fluids covered by the invention are a suspension of particulates in fluid, a particulate slurry and foamed systems. The filter media 74 can be a suspension of particulates in fluid. The particulates in this application could be of any size appropriate for controlling sand production from the reservoir. In addition, the proppant, or particulate, specific gravity preferably ranges from 1.1 to 2.8. The specific gravity and other characteristics of the particulate will vary, however, and are determined by the required downhole hydrostatic pressure. The use of lightweight particulate is preferable where the major mechanism for inducing a squeezing of the ‘void filling fluid’, or filter media, is caused by expansion of the sand-control device. Particulate, or proppant, loading preferably ranges between 0.1 to 20 ppg, but is not limited to this range. The carrier fluid for the particulate can be water-based, hydrocarbon-based, or an emulsified system. Examples of water based system include, but are not limited to, clear brines or those that include the use of gelling agents such as HEC, xanthan, viscous surfactant gel or synthetic polymers. In addition, the water-based system bay be weighted by the addition of salts such as calcium chloride or other conventional brines as used in the oil field. Examples of hydrocarbon based systems include, but are not limited to, the use of gelled oils and drill-in fluids. Emulsified systems (water external or oil external) can also be used. Another filter media system 74 can be applied is a solid particulate/cement slurry mixture that after liquid removal by the squeezing action of the expansion of the sand-control device, and after the passage of time, creates a porous media through which hydrocarbons and other fluids can be produced while controlling fines migration. Particulate concentrations can range from 5 to 22 ppg, but will vary based on application conditions. The density of the particulates can range from 1.1 to 2.8, but may also vary. Testing with such a system containing 20/40 sized sand indicated that a permeability of 40 Darcy and an unconfined compressive strength of 900 psi could be developed with this system. Such a system, with these permeability and strength factors, is desirable in most well formations. A system in which a particulate coated with a resin material is also covered by this invention. The resin material may be activated by well temperature, time, stress induced by liquid removal, or through the use of an activator that is injected after the liquid removal process. Resins and activators are well known in the art. The filter media can be a foamed system, with or without particulates, that creates an open-faced permeable foam after liquid removal. A chemical treatment, after dehydration, may be necessary to enhance the permeability of the foam. A typical system for this application could be a foamed cement to which a mixture of crosslinked-gel particulate and carbonate particles of appropriate size have been added to the slurry. The crosslinked gel particles have a chemical breaker added to them. After liquid removal the crosslinked gel particles are broken by the in-situ breaker leading to the creation of a porous media. The permeability of the porous media can be further enhanced by pumping an acid to dissolve the crosslinked gel and the calcium carbonate particles. This invention also covers the use of alternative materials that can decompose by contact with conventional brines or oil soluble systems such as oil soluble resin or gilsonite that can be dissolved by contact with hydrocarbons. Degradable semi-solid gel particulate material can also be used in the filter system to act as a means to increase the porosity of the filter media after the carrier fluid is removed by squeezing. This will enhance the permeability and prevent excessive losses in permeability caused by the dehydration process. Various types of foam and particulate mixtures, and methods for improving permeability and porosity, will be recognized by those of skill in the art. Surface modifying agents can be added to the solid material in the filtration media. These surface modifying agents can improve the filtration properties of the particulate material by stopping fines migration at the open hole, filter interface and prevent plugging of the filter media itself. Surface modifying agents can also be added to the particulate material in the filtration media to provide cohesive bonds between particles when the suspending fluid is at least partially removed by the squeezing effect of the sand-control device expansion. The cohesive strength in the pack will prevent movement of particles in the pack during production operations which will reduce any chance for well tool erosion. Alternately, the permeable filter media is placed external of the sand-control device 30 prior to running and expanding in the subterranean wellbore. An open-cell, permeable, expandable, foamed material is molded or cast into a cylinder shape 90 , sleeve or jacket. This foamed sleeve 90 is then slid over the expandable sand-control device 30 to encapsulate its outer wall before its downhole placement. The wall thickness of the sleeve is preferably from ¼ inch to 1 inch, depending on the diameters of the screen and wellbore. The permeable sleeve 90 can be tightly fit or glued to the device surface to prevent it from sliding off of the device during operation. The outer surface of the foamed sleeve 90 can be coated with high tensile strength “film” 92 or material to protect the sleeve from tearing or ripping during handling and installation of the expandable screen downhole. The deformability of the foam allows it to fill up the void space or gaps between the screen and the formation as the screen is expanded against the open-hole wall 26 . The foamed sleeve 90 can also be impregnated with synthetic beads, sands or proppant, to maintain permeability of the porous medium under compression. The foamed sleeve 90 can also be impregnated with treatment chemical that can be slowly released, such as a breaker that can break up or dissolve the filter cake remaining after drilling operation. The treatment chemical can be mud breakers, such as oxidizers, enzymes or hydrolysable esters that are capable of producing a pH change in the fluid, scale inhibitors, biocides, corrosion inhibitors, and paraffin inhibitors that can be slowly released during production. Another concept includes the use of a flexible, expandable, and permeable membrane 94 , which is prepared in the shape of a sleeve or jacket to provide similar function as described in the above concept. The permeable sleeve, which can be pulled over the expandable screen covering its outer wall, acts as pouch containing the filter medium 74 (i.e. lightweight beads, sands, proppant, etc.). As the screen is expanded, the filter medium in the deformable membrane fills up the annulus space 72 . This permeable membrane can be prepared from materials such as metals, polymers, or composites, so that it can tolerate both physical and chemical requirements of downhole conditions. After placement of the filter media 74 in the wellbore annulus 72 , the sand-control device 30 is expanded. As shown in FIG. 2, wherein the work string 50 has already been retrieved, the sand-control device 30 can be expanded from bottom-up. The expansion can occur top-down as well depending on the well tool configuration. The sand-control device 30 is adjacent the zone of interest 12 . The retractable expansion tool 52 is activated to its expanded position, as seen in FIG. 2, to expand the sand-control device. The sand-control device 30 is radially expanded from its unexpanded, or initial position or radial size 80 , to its expanded position 82 . During expansion, liquid L from the filter media 74 flows along lines F into the sand-control device 30 and then into the tubing string 10 . If the expansion assembly is operated from the top-down, it may be desirable for the expansion assembly to have a bypass port 81 through which the fluid F may travel up into the tubing string 10 . As at least a portion of the fluid F is squeezed from the filter media 74 , the particulate material P is tightly packed into the annulus 72 . The filter media particulate P cannot flow into the sand-control device 30 . The screen or slotted holes of the sand-control device 30 are selectively sized and shaped to prevent migration of the particulate P into the device 30 . The filter media particulate P remaining in the annulus 72 acts as a filter during production of hydrocarbons H from the well formation 14 . Fines, or small sand particles S, are trapped or filtered by the remaining media and prevented from flowing into the sand-control device 30 . The filter media is pumped into the annulus 72 to fill up the annular space. However, conventional methods of packing often leave undesirable voids, or areas which are not filled with packing media. Preferably, in the current invention, as the filter media is squeezed between the wellbore wall 26 and the tubing string 10 during expansion of the sand-control device 30 , any voids not previously filled are eliminated and filled-in with the filter media. The filter media can prevent fines from migrating to the sand-control device, thereby preventing clogging and erosion of the well tools and sand-control device, and can prevent the formation from collapsing thereby reducing the production of fines. The tight packing of the media against the wellbore wall can also prevent shale spalling. Shale spalling could result in plugging of the media and sand-control device. Preferably, when the filter media 74 is pumped into the annulus 72 , the filter media fills the annulus at least a set distance into the cased portion 22 of the well as shown. It will be seen therefore, that the apparatus and method addressed herein are well-adapted for use in flow testing an unconsolidated well formation. After careful consideration of the specific and exemplary embodiments of the present invention described herein, a person of skill in the art will appreciate that certain modifications, substitutions and other changes may be made without substantially deviating from the principles of the present invention. The detailed description is illustrative, the spirit and scope of the invention being limited only by the appended claims.	In general, a method is provided for completing a subterranean wellbore, and an apparatus for using the method. The method comprises positioning an expandable sand-control device in the wellbore thereby forming an annulus between the sand-control device and the wellbore; depositing a filter media in the annulus; and after the depositing step, radially expanding the sand-control device to decrease the volume of the annulus. The sand-control device can be a sand screen or slotted or perforated liner having radially extending passageways in the walls thereof, the passageways designed to substantially prevent movement of the particulate material through the passageways and into the sand-control device. Where a slotted liner is desired, the passageways can be plugged during positioning and later unplugged for production. Another embodiment of the method and apparatus presented herein comprises positioning a well-completion device into the wellbore, thereby forming an annulus between the well-completion device and the wellbore, the well-completion device having a flexible, permeable membrane sleeve surrounding an expandable sand-control device; and thereafter radially expanding the sand-control device to decrease the volume of the annulus, thereby also expanding the membrane sleeve. The well-completion device can further include a layer of filter media encased between the membrane sleeve and the sand-control device. The filter media may be of any type known in the industry. Preferably, the membrane sleeve, when expanded, substantially fills the annular space extending between the wellbore and the sand-control device by deforming to substantially contour the wellbore.	4
[0001] This application claims priority from U.S. Provisional Patent App. No. 60/447,107 filed Feb. 12, 2003. BACKGROUND OF THE INVENTION [0002] The technology of autostereoscopic electronic displays, usually involving flat panels, has advanced to the point where it is now viable for many applications. Dedicated autostereoscopic displays are available, but there are computer users who wish to have the ability to move between word processing and stereoscopic visualization applications, for example. These users require a display that can provide a clear image for both autostereoscopic and planar applications. For displays using a lenticular selection device, the problem is that the refractive properties of the lens sheet fragments distorts small type and fine detail in the planar mode. Therefore, with the lens sheet remaining in place, the display cannot be used for important applications such as e-mail, spreadsheets and word processing. [0003] Many approaches have been previously considered to address this problem. For example, a display utilizing an overlay such as a lenticular screen has been described in co-pending U.S. patent application Ser. No. 09/943,890, entitled AUTOSTEREOSCOIC LENTICULAR SCREEN. With the lenticular ridges facing inward towards the flat panel surface, a chamber is created between the flat panel surface and the lenticular ridges to hold a liquid that is emptied to provide 3-D viewing and filled to defeat the refractive properties of the screen. [0004] U.S. Pat. No. 5,500,765, entitled CONVERTIBLE 2D/3D AUTOSTEREOSCOPIC DISPLAY, discloses a display having a lenticular overlay in close contact with the flat panel front surface, but with the ridges facing outward. To defeat the lenticular refractive characteristics, a mating inverse lenticular screen is placed atop the lenticular screen in proper alignment so that the second screen negates the refraction of the original. [0005] Another approach is to fabricate a removable lenticular screen that is held firmly in precision alignment when placed in juxtaposition with the flat panel in close contact with the display surface. [0006] The method we describe here is one in which the lenticular sheet does not need to be physically removed from the display, thus promoting convenience of operation and relieving the user from the requirement of finding a safe place to store the lenticular sheet. In addition, extreme precision of alignment is achieved because of the special orientation of the lenticules, as will be described below. SUMMARY OF THE INVENTION [0007] A dual mode autostereoscopic display is disclosed. A lenticular sheet having a thickness which is less than its focal length is coupled to a display surface by a mechanical mechanism. The mechanism raises and lowers the lenticular sheet over a fixed distance between a raised position and a lowered position. In the raised position, the lenticular sheet is parallel to and separated from the display surface and the user observes stereoscopic content. In the lowered position, the lenticular sheet is parallel and close to the display surface, and the user observes planar content. BRIEF DESCRIPTION OF THE DRAWINGS [0008] [0008]FIG. 1 is a perspective view of an adjustable lens sheet in accord with the present invention. [0009] [0009]FIG. 2 a is a ray diagram of the lens sheet of FIG. 1 when the rays come to a focal point at the plane of the display. [0010] [0010]FIG. 2 b is a ray diagram of the lens sheet of FIG. 1 when the rays come to a focal point that is plane of the display. [0011] [0011]FIG. 3 a is a schematic representation of the lenticular orientation of a conventional lenticular sheet. [0012] [0012]FIG. 3 b is a schematic representation of the lenticular orientation of a lenticular sheet in accord with the teachings of Winnek. [0013] [0013]FIG. 4 is a cross section of the lenticular surface showing how various rays contribute to antireflection properties. [0014] [0014]FIG. 5 is a side view of the elevator mechanism used to raise or lower the lens sheet. DETAILED DESCRIPTION OF THE INVENTION [0015] A lenticular screen of the kind first described by Hess in U.S. Pat. No. 1,128,979, includes a series of parallel, semi-cylindrical sections or lenticules 103 , as shown in FIG. 1. These lenticules garble or distort fine type or alphanumerics and icons when used in association with a computer graphics display. Thus, while this type of lens sheet is perfectly fine for autostereoscopic content, it destroys the ability to read small point size text. We have discovered that when such a lens sheet is moved closer to the display so that, in effect, it focuses behind the display, its refractive properties are such that the fine text and alphanumerics can now be read. [0016] As shown in FIG. 3 a, Hess employs a lens sheet in which the boundary 109 of the lenticules, defined as lines formed by the intersection of individual lenticules with each other, are parallel to each other. In addition, the boundaries 303 of lens sheet 301 are mutually parallel and parallel to the vertical edges 305 of the lenticular sheet 307 . The sheet is assumed to be a rectangle so that horizontal edge 307 is perpendicular to vertical edge 305 . It is also assumed that the edges 305 and 307 are parallel to the vertical and horizontal edges of the rectangular display screen 104 with which they are associated. [0017] When the orientation of the lenticules is angled as described in U.S. Pat. No. 3,409,351 to Winnek, the crucial ability to align such a moveable lenticular sheet in its autostereoscopic position is much improved compared with the Hess arrangment. The Winnek orientation provides significant advantages when used in our embodiment because it provides superior images with elimination of optical moiré and pattern noise, and as a great benefit, it suppresses reflection in both planar and autostereo modes. [0018] It is possible to switch between planar and autostereo modes. Referring to FIG. 1, the lens sheet 102 is fabricated so that its thickness 106 is relatively thin compared with its focal length. Such lenticules can be produced on a substrate with a casting or lamination process, or the lens sheet can be an integral unit that was created in plastic material with a hot press or by similar means. The means of fabrication is irrelevant for our purposes; it doesn't matter whether the lens sheet is of integral construction or produced by means of lenticules coated or cast on a substrate. The important point is that the focal length of the lens sheet be appreciably longer than its thickness 106 . [0019] Readers who are skilled in the art will realize that such a lens sheet has a focal length in one direction only because the optics are cylindrical, rather than spherical as is usually employed in imaging optics. In addition, persons familiar with the art will recognize that higher power curves, rather than sections of cylinders, may also be employed without a loss of generality. [0020] The display screen 107 can be any kind of a flat-panel display, such as a liquid crystal display (LCD) device or a plasma panel. Its front surface 104 , wherein the pixel array is to be found, must be parallel to the rear surface 110 of the lens sheet 102 . The distance from the rear surface 110 of the lens sheet 102 to the front surface 104 of the display screen 107 is represented by dotted lines 105 . The dotted lines are also exhibited in other portions of the drawing and are not labeled, but are meant to be equal in distance to 105 . [0021] A Cartesian grid 108 is included on FIG. 1, using the standard that the horizontal direction is x, the vertical direction is y and the z direction is perpendicular to y and x. Thus, the vertical and horizontal edges of the display and lenticular sheet are oriented in the y direction and the x direction, respectively. The lenticular sheet is adapted to move up and down in a direction that is parallel to the z-axis by a distance 105 . [0022] Before describing the mechanism for accomplishing movement of the lenticular sheet, we refer to FIGS. 2 a and 2 b, which are simply ray diagrams showing the lenticular sheet in two positions. In FIG. 2 a, the lenticular sheet 209 has individual lenticules 202 , and a typical lenticule has an optical center 207 . The incoming parallel rays 201 are refracted by the lenticule, as shown by rays 204 which converge or come into focus at point 203 at or near the surface of display screen 205 . The distance 208 from the optical center 207 to the plane of the display screen is the focal length. The rear surface of the lens sheet is 110 . [0023] For clarity, note that FIGS. 2 a and 2 b correspond closely with the perspective drawing of FIG. 1, except that FIGS. 2 a and 2 b are cross-sectional drawings showing the refraction of rays to make an important point about this optical system. [0024] In FIG. 2 b, the optical system is virtually identical, but the rear surface 110 of the lens sheet is in intimate juxtaposition with the front surface 104 of the display screen 107 . This is shown with a small gap for purposes of illustration so that we may distinguish one surface from the other. Such a gap may or may not be required depending upon the optical properties of the lens sheet 209 and the focal length 208 . In the case of FIG. 2 b, the focal point 203 is now well within the surface of the display; that is to say, behind the surface of display 205 . One could consider the lens sheet as being out of focus with respect to the individual picture elements of display 107 . It is in this position of close proximity that the alphanumerics, fine text, or icons are legible. [0025] Our experiments have shown that a lens sheet placed in the position indicated by FIG. 2 a provides a good autostereoscopic image, whereas a lens sheet placed in the position indicated by FIG. 2 b, in which the focal point is well behind the surface of the display, provides alphanumerics that are clear and visible. In fact, it is as if the lens sheet no longer existed, and the viewing of information with fine detail such as text is now perfectly acceptable. By translating the lens sheet between the positions indicated in FIGS. 2 a and 2 b, we can have a dual-purpose display: a display that works autostereoscopically, as shown in FIG. 2 a, or a display that works in the planar mode where fine text and detail are legible, as shown in FIG. 2 b. [0026] [0026]FIG. 1 shows the lens sheet 102 held above the display 107 and display surface 104 by a distance 105 . It is well known from geometry that three points determine a plane, so that the lens sheet can be accurately located so that its inner surface 109 is parallel to the front surface 104 of display 107 . We are making the assumption that the lens sheet 102 and its individual lenticules 103 are evenly spaced, and that there are no irregularities in the distance 106 . Hence, we can use as a reference the inside surface 109 of the lens sheet. Therefore, plane surface 109 must be parallel to plane surface 104 for proper functioning of the lens sheet in the autostereoscopic mode when the lens sheet is held at distance 105 . The assumption here is that sharp focus is obtained, as shown in FIG. 2 a, so that focal length 208 corresponds to the approximate distance from the optical center 207 to the surface of the display 205 . Therefore, distance 208 is not equal to distance 105 , because the optical center of the individual lenticule 103 in FIG. 1 may or may not be within the physical extent of the lens sheet. In any event, when the lens sheet is held at distance 105 , the lens sheet is functioning in an autostereoscopic mode. When distance 105 is reduced, then we have the condition which is shown in FIG. 2 b, namely that the focal length of the lens sheet 208 and the point of sharp focus is actually behind or within the display at point 203 , in which case the display now functions in the planar mode. [0027] Our device functions at two distances—close to the surface of the display, and further away from the surface of the display. In both cases, it is highly desirable that the inside plane surface of the lenticular screen be parallel to the front surface of the display. It is especially critical that this occur when the lens sheet is in its extended position, because in that position it functions autostereoscopically. In the collapsed position, when the lens sheet is closest to the display screen, this is not critical, and the parallelism between the inside surface of the lens sheet and the front surface of the display screen may be approximate. [0028] Therefore, some mechanical means must be provided for translating lens sheet 102 along axis z so that the distance 105 changes, and such a means will be described below. Also, when the lens sheet is in its extended position so that it functions as an autostereoscopic display, it must always return to the same location so that there is no movement in the x or y direction. That is because individual lenticules 103 must be in proper juxtaposition with picture elements or pixels of the display screen surface 104 . What is contemplated here is that the lens sheet is moved along the z-axis. One might describe it as being “up and down,” and because three points determine a plane, it is critical that when it is in autostereoscopic mode and distance 105 must be achieved, that the lens sheet is located at three points in the z plane, and also properly located in the y and x planes. If the z condition is not fulfilled, the lens sheet will not achieve even focus over the surface of the display, and if the y and x conditions are not fulfilled, then the proper juxtaposition of a lenticule and pixel will not be achieved, and there will possibly be shifting of the image so that central viewing zones will not remain in a constant location, or possibly that portions of the display screen will be in pseudoscopic rather than the stereoscopic mode when the observer is at a particular location. [0029] In order to overcome such limitations with regard to accurate positioning of the lenticular sheet, the preferred embodiment is the Winnek configuration 302 shown in FIG. 3 b rather than the Hess configuration 301 shown in FIG. 3 a. [0030] In looking at the registration precision requirements for the two approaches, we find that vertical alignment of the Hess configuration 301 demands that the pixel pitch and the lenticular pitch be aligned so precisely that no moiré pattern is generated. The generation of a moiré pattern, for one simple case, is seen when two or more patterns consisting of parallel linear segments are rotated (misaligned) by some amount. It has been found that the moiré pattern can be seen with as little as 0.01° rotation. The amount and severity of the moiré pattern seen depends to a great extent on the ratio of the pitch and contrast levels of the patterns that are generating the effect. If the lenticular screen and display matrix are to be matched, one must take this into account in the making of the initial lenticular tooling and the making of the lenticular array, and allowing for any difference in the coefficient of thermal expansion between the display screen Cartesian matrix and the lens sheet. The matching of the two patterns requires not only thermal stability, but also precision of less than 0.001 parts per pixel pitch of the display matrix for the lenticular screen pitch. In a display with a pixel width of 0.125 mm, this is a precision of less than one micron! Another difficulty precluding this approach is that there is poor image quality found for the various color element transitions and where the black interstices between display pixels are found there is an added beat pattern further exacerbating the difficulty of making precise registration between the lens sheet and the display pixel matrix. [0031] This significant spurious pattern generation does not consist of a single set of lines rotating through the image, but since we have a pixel matrix to deal with, pattern components are generated from the horizontal as well as the vertical interstices. In addition, secondary and tertiary patterns are generated once the primary patterns are cleared up by means of varying lens sheet pitch and alteration of the Winnek angle, probably because of interaction with their predecessors. We believe that the cascading patterns diminish in contrast and amplitude because each offspring is of lesser contrast that its source. If one could perceive extremely low contrast objects within the range of human acuity, one could then perceive fourth and fifth generation patterns as well. [0032] Thus, we intentionally rotate the optical array of FIG. 3 b to avoid the stringent requirements of precision alignment of the pattern sources, namely, the display matrix and the lenticular screen. If one intentionally rotates the lenticular screen through some arbitrary angle and thus generates the numerous moiré patterns resultant from that action, one can also find a point where the myriad of patterns are subtle and less obvious to the casual observer. This angle setting (which we call angulation) is thus the configuration of choice for that display. This approach to marrying the lenticular array to the display relieves the manufacturing constraints that have plagued approaches attempting to match precision parallel lenticules to the matrix of the display. [0033] There is a secondary benefit which is brought about by this rotation. It can be shown that the lenticular array, when so rotated (see FIG. 4), acts through optical means to significantly disperse reflections of ambient light sources 401 , which would otherwise cause substantial degradation to the image being viewed. This mechanism is the simple dispersion of an illumination onto a convex optical surface 404 , wherein the only portion seen by an observer 402 looking at the optic would be a small spot at the lens. The dispersion efficiency is then known to be equivalent to a specular reflection spread through the optical range of the lens front surface 403 . If the lens dispersion moves through a 100° angle, then the observer will see {fraction (1/100)} th of the reflective illumination as compared to the “flat” specular surface. It is important to note that this benefit is observed in both the planar and autostereo modes. In other words, this antireflection property is not dependent upon the distance from the lens sheet to the surface of the display. [0034] Given the practicality of fabricating such lenticular arrays, one is limited in manufacturing perfectly formed lenticular ridges. Given this, it is seen that if the lenticular array is not rotated, an additional reflection may be seen along the troughs between the lenticules providing additional reflections toward the observer. This can be on the order of 4% of the total reflections seen and is certainly observable with a vertical orientation. With the rotation of the array, this trough reflection becomes insignificant, on the order of greater than 1% of the total reflection observed. These values will vary with different manufacturing techniques. Higher quality and better precision will act to reduce these secondary “trough” reflections. [0035] We shall now describe the elevator mechanism that is our preferred embodiment for raising and lowering the lens sheet to switch between planar and autostereoscopic modes. The operation of the elevator mechanism is best understood with reference to FIG. 5. Although the following description is the preferred embodiment of the elevator mechanism, it does not presume to define the various mechanisms that might be employed to provide this function. Therefore, a person skilled in the art will be able to devise means to replicate the function of what we are describing here without adding any inventive novelty. [0036] In this embodiment, shown in FIG. 5, the monitor 501 has the LCD module 502 on top, which is fixed in position and height. The lenticular screen 503 , mounted within a frame for robustness, has a multiplicity of small followers 504 . These followers 504 are engaged by the movement of a multiplicity of ramps 505 , which are moved laterally thereby pushing the lenticular screen-in-frame to move upwards away from the LCD outer surface. The ramps are fabricated of a spring-like material sufficient in strength to apply firm pressure upward when engaged on the ramps, but flexible enough to allow adjustable screws 507 to define the upper limit of travel for the lenticular screen mounted in its frame. The lenticular screen-in-frame is constrained both in the x and y directions by adjustable guides 506 , which are mounted on the display module body. The adjustable guides also act to define the upper limit of travel of the lenticular screen-in-frame, which also defines the desired focus position of the lenticular screen. This focus adjustment is accomplished by turning the adjustment screws 507 , with the lenticular screen being pressed firmly in the up position until the correct focus is attained. [0037] We have described a system for viewing autostereoscopic images with a flat panel display, and the ability to covert the display to a functioning planar display without the removal of the lens sheet. A translation of the screen forward or backward, with respect to the plane of the display surface, is all that is required. In addition, the lenticules used in our embodiment have their boundary intersections tipped to the vertical, or with some degree of angulation, as described in the Winnek patent. In this orientation, the lens sheet surface functions as an antireflection device in both planar and autostereo modes.	A dual mode autostereoscopic display. A lenticular sheet is coupled to a display surface by a mechanical mechanism. The lenticular sheet has a thickness which is less than the focal length. The mechanism is used to raise and lower the lenticular sheet over a fixed distance between a raised position, wherein the lenticular sheet is parallel to and separated from the display surface, and a lowered position, wherein the lenticular sheet is parallel and close to the display surface. In the raised position, a user observes stereoscopic content. In the lowered position, the user observes planar content.	6
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The present invention is a continuation-in-part application of U.S. patent application Ser. No. 10/920,593 entitled “Circular Saw with Laser and Protractor” filed on Aug. 18, 2004, the specification and drawings of which are hereby expressly incorporated by reference. BACKGROUND OF THE INVENTION [0002] The present invention relates to a measuring kit and, more specifically, to a measuring kit that includes a laser, framing square, protractor and their combinations. [0003] In the construction industry, as well as other industries, laser markers are becoming commonly used throughout the industry. Laser beams can serve as a line mark for use in diverse processes such as guiding, aligning, and locating. The laser markers can be used to lay out and determine the configuration of a construction project. [0004] Ordinarily, in forming various types of elements which require various angles, cuts and the like, it is desirable to utilize a tool which will enable the project to be level and square. In order to accomplish leveling and squareness, the workman must perform various measurements in order to obtain the desired results. Often times, it is difficult to accurately perform these measurements. Thus, it would be desirable to have tools which enhance the workman's ability to provide accurate and precise measurements as well as accurate and precise leveling and squareness. [0005] The present invention provides the user with a kit which enables accurate measurement. The kit provides a laser marker which can be angularly adjusted along a protractor. Also, the present invention provides a squaring feature wherein the laser beam can be squared onto the workpiece and provide a straight and accurate marking. The present invention provides a squaring device which enables precise layout of a project. [0006] According to a first aspect of the invention, a laser square protractor kit comprises a laser having a housing with a first positioning member coupled with the housing. The protractor has a base with a second positioning member. The first and second positioning members cooperate with one another to position the housing with the protractor base. The protractor base includes a third positioning member. A framing square is adapted to couple with the base in the third positioning member. The base further includes a reference edge to square the protractor on a workpiece. The reference edge is pivotable from a first extending position projecting from the base, to provide squareness, to a retracted position where it is flush with the base. The base also includes a second reference member to reference the framing square with the protractor base. The second reference edge projects from the base. The base also includes a projecting support member which, with the reference edge, forms a channel to receive the framing square. The base includes registration members to position the laser housing about a plurality of predetermined angled positions on the protractor. Also, the laser housing is adjusted to any angle of the protractor. [0007] In accordance with the second embodiment of the invention, a laser protractor kit comprises a laser having a housing and a first positioning member coupled with the housing. The protractor has a base with a second positioning member. The first and second positioning members cooperate with one another to position the housing with the protractor base. The base includes a reference edge member to square the protractor on a workpiece. The edge member is pivotable from an extended position, projecting from the base for squaring, to a retracted position flush with the base. The base also includes registration members to position the laser about a plurality of predetermined angled positions on the protractor. [0008] According to a third aspect of the invention, a laser and framing square kit comprises a laser having a housing with at least one positioning member extending from the housing. A framing square has at least one edge. The at least one edge cooperates with the at least one positioning member to position the laser housing with the framing square. The laser housing ordinarily includes a pair of positioning members projecting from the housing. The pair of members are spaced with respect to one another to contact the at least one edge of the framing square. The framing square has at least two edges spaced and parallel from one another. The pair of positioning members on the housing may be positioned such that each member cooperates with one of the two edges of the framing square. [0009] From the following detailed description taken in conjunction with the accompanying drawings and claims, other objects and advantages of the present invention will become apparent to those skilled in the art. BRIEF DESCRIPTION OF THE DRAWINGS [0010] The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: [0011] FIG. 1 is a perspective view of the laser protractor framing square kit in an assembled position. [0012] FIG. 2 is a bottom perspective view of the laser generator. [0013] FIG. 3 is a side elevation view of the laser generator of FIG. 2 . [0014] FIG. 4 is a detailed perspective view of a reference member of the protractor. [0015] FIG. 5 is a perspective view of the bottom of the protractor base. [0016] FIG. 6 is a perspective top view of the protractor base. [0017] FIG. 7 is a perspective view of the laser and protractor. [0018] FIG. 8 is a top plan view of the laser on the protractor in the desired position. [0019] FIG. 9 is a view like FIG. 8 with the laser generator in a second desired position. [0020] FIG. 10 is a perspective view of the protractor and framing square. [0021] FIG. 11 is a perspective view of the bottom of the protractor. [0022] FIG. 12 is a perspective view of the laser generator and the framing square. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0023] The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. [0024] Turning to the figures, particularly FIG. 1 , the laser beam generator, protractor and framing square kit is illustrated and designated with the reference numeral 20 . The kit 20 includes a laser generator 22 , a protractor mechanism 24 , and a framing square 26 . As seen in FIG. 1 , the laser generating member 22 removably nests on the protractor 24 . Also, the framing square 26 removably nests underneath the protractor 24 . [0025] The laser generator or marker 22 is like that described in U.S. application Ser. No. 10/920,593 entitled “Circular Saw with Laser and Protractor”, filed on Aug. 18, 2004 and assigned to the same assignee as the present invention, the specification and drawings of which are herein expressly incorporated by reference. The laser generator includes a housing 28 which is formed from a pair of shell-like sections 32 , 34 . A window 36 is formed generally centrally between the two shell-like sections 32 , 34 . The window 36 enables the laser to project from the window 36 . The rear wall of the housing includes two shelves 40 , 42 each of which extends perpendicular from the wall. Each of the shelves 40 , 42 is formed with a tapered section which tapers inward from the outboard ends to a slot between respective inboard ends. A marking notch 46 with an alignment mark is located within the slot. The notch 46 is in alignment with the window 36 and a laser beam which is eventually projected through the window 36 . This arrangement facilitates the locating of the laser housing on a surface of a workpiece with respect to a reference point on the surface. An undersurface of the rear wall is flush with an external surface of the housing base with the undersurface and the external surface being located in a common external plane. The wall is formed with a first reference or support leg 52 and a second reference or support leg 54 . The first and second support legs 52 , 54 are spaced with respect to one another. Each of the spaced first and second legs 52 , 54 extend perpendicular and outward from the base by a prescribed extension distance from the undersurface of the wall section. Also, the legs 52 , 54 may be used to align the laser marker 22 on the edge of a workpiece to project a line perpendicular to the edge. [0026] A nest 60 is formed in a central location of the base to receive a magnet 62 . The magnet 62 has a disk shape. The nest 60 includes the passage 64 of a desired diameter, which extends through the base from a generally central portion of the external surface and inward of the laser housing. A ledge (not shown) is formed about an inboard portion of the passage at a diameter larger than the prescribed diameter of the passage. The magnet 62 is formed with a diameter which is approximately the same as the diameter of the ledge. Thus, when the magnet 62 is placed on the ledge, the ledge forms a mechanism to locate the magnet 62 within the laser housing to preclude movement of the magnet 62 out of the nest in the direction outward of the laser housing. One side of the magnet is exposed externally out of the housing. The externally exposed outward portion of the passage 64 and the external exposed portion of the magnet 62 form a circular recess 66 which extends inward from the base 68 the desired distance. This receives the protractor boss as will be explained herein. [0027] The protractor 24 includes a base 102 which includes a semi-circular portion 104 and a rear rectangular portion 106 . The semi-circular portion 104 may include a scale with numeral 0-180 identifying the various degree angles. The rectangular portion 106 is continuous with the semi-circular portion 104 . The semi-circular portion 104 may also include raised radiants 105 which illustrate various common degrees such as 0, 30, 45, 60, 90, 120, 135, 150 and 180. Also, a circular boss 108 and groove 110 may be positioned between the semi-circular portion 104 and the rectangular portion 106 . The boss 108 includes at its center, a central disk 112 which receives the magnet 62 of the laser marker 20 . The circular member 112 is centered on the protractor baseline and includes a raised metallic portion which fits into the recess of the housing. Alternatively, a friction fit mechanism, which provides the rotation feature, could be used. The boss 108 includes a plurality of apertures 113 to receive the legs 64 , 66 of the housing as illustrated in FIGS. 7-9 . The apertures 113 are positioned such that the laser marker is positioned at the desired identified radiant. Thus, by moving the laser housing pins 52 , 54 from hole to hole 113 , a different angular position can be determined. Also, due to the circular recess 66 and boss 108 , the laser marker 22 may be rotated to any desired degree angle. [0028] The rectangular backing member 106 includes a pair of reference members 114 , 116 . The reference members are pivotally secured to the backing member 106 . The reference members 114 , 116 enable the protractor 24 to be referenced onto a workpiece. Likewise, when the protractor 24 is to be positioned in a non-reference point, the reference members 114 , 116 are pivoted so that they are flush with the protractor and therefore do not extend from the bottom of the protractor as illustrated in FIG. 5 . Thus, the reference members can be pivoted from a first to a second position to align and enable the protractor to be positioned against the edge of a workpiece. Also, the protractor includes stops 118 , 120 which stop the travel of the reference members 114 , 116 . The stops position the reference members 114 , 116 perpendicular to the rectangular portion of the base 106 . [0029] The protractor base 102 includes a bottom surface 130 . The bottom surface 130 includes a leg 132 on the front semi-circular portion 104 . Also, the bottom 130 includes a reference edge 134 . The reference edge 134 can be a metallic member which extends from the bottom 130 . The reference edge 134 is positioned along the zero baseline of the protractor. The reference edge 134 and the leg 132 form a channel 136 which receives the framing square 26 . Thus, the framing square 26 can be slid longitudinally in the channel 136 . Also, when the reference members 114 , 116 are in their flush position, as illustrated in FIGS. 4 and 11 , the framing square 26 can be positioned on either side of the reference edge 134 . The framing square 26 can be positioned under the rectangular portion 106 for measurement on either side of the protractor. Further, the reference edge 134 can abut the edge of a workpiece or wall to align the protractor. [0030] The framing square 26 is generally formed from a metallic material and includes two leg portions perpendicular to one another forming an L-shape. The framing square 26 has a thickness conventional in the art which can easily slide into, or enable the protractor 24 to slide on via, the channel 136 between the reference edge 134 and leg 132 of the protractor 24 . Also, the edge is such that the framing square can slide underneath the rectangular base portion 106 . [0031] Turning to FIG. 12 , the framing square 26 can be used with the laser marker 22 . As seen, the legs 52 , 54 are positioned against the edge of the framing square 26 . The laser marker 22 can be moved into any desired position along the framing square 26 . Thus, the laser marker 22 projects a line which is perpendicular to the edge of the framing square 26 . The laser marker's magnet 62 holds the laser marker in position on the square. Also, the laser marker 22 could be positioned transverse to the square so that the housing legs could be riding along parallel edges of the framing square. [0032] The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.	A laser, square, protractor kit has a laser marker with a housing. The housing has a first positioning member. The protractor has a base with a second positioning member which cooperates with the first positioning member to position the housing on the protractor base. The protractor base also includes a third positioning member. A framing square is coupled with the third positioning member enabling the protractor to be positioned on the framing square.	6
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to holsters and, more specifically, to a holster having a reinforced frontal lip, providing the necessary rigidity for one-hand reholstering while preserving the thinness and concealability of the holster. 2. Description of the Related Art Holsters intended for discreetly carrying a defensive handgun have been in existence since guns were first made small enough for concealed carry. Today, such holsters are used both by plainclothes or off duty police officers and by an increasing number of private citizens who have felt a need to take precautions to ensure their safety. Most people who carry a handgun prefer to carry it at belt level, positioned on or slightly behind the strong side hip. A few prefer to carry the gun on or slightly in front of the weak side hip, commonly known as crossdraw carry. One of the most popular styles of concealment holsters is the inside waistband holster. Such holsters are worn inside the waistband of the wearer's pants, slightly behind the strong side hip, with only the upper lip of the holster and grip of the gun protruding from the pants. A belt clip or loop secures the holster to the wearer's belt. The top of the holster is covered by a jacket, sweater, or untucked shirt. This type of holster is especially popular with police, because the draw from this type of holster is very similar to the draw from a duty holster, providing for simplified training and practice. To be truly useful, such a holster must be able to perform several functions well. First, it must be easily concealed to avoid unnecessarily alarming casual observers, which is accomplished in part by keeping the thickness of the holster's leather to a minimum. Second, it must be comfortable to wear for long periods of time. Third, it must hold the gun securely in place. Fourth, it must provide quick access to the gun so that the wearer can respond properly to unexpected emergencies. Fifth, it should ideally allow for reholstering the gun using only one hand. This last function is particularly important for police, who must frequently control a suspect with one hand while reholstering a gun with the other. Current inside waistband holsters come in two basic types. The first type is constructed of flexible, unmolded leather or nylon. This construction has several disadvantages. These holsters are not sufficiently snug fitting to hold a gun in place, and usually require the use of a safety strap passing over the gun's hammer. Even with safety straps equipped with thumb breaks, access to the gun is slowed. When the gun is drawn, belt pressure on the holster immediately causes it to collapse, requiring the wearer to use two hands in reholstering the gun. The second type of inside waistband holster is made from rigid leather, molded in the shape of the specific gun to be used with the holster. This type of holster usually has an additional molded leather reinforcement around the front and sides of the gun pocket, and frequently includes a metal reinforcement between the holster body and leather reinforcement. The molded leather fits the gun very closely, providing a high degree of friction between the holster and gun. This friction is sufficient to hold a gun in place without the need for a safety strap, providing the fastest possible access to the gun. These holsters will remain open when the gun is drawn, allowing a the wearer to reholster the gun with one hand, without looking at the holster. However, the total thickness which must be concealed includes the gun, two layers of holster body (one on each side of the gun), two additional layers of leather reinforcement, and possible two layers of metal. All of this added thickness can create a noticeable bulge in the wearer's clothing, revealing the presence of the gun. Additionally, the holster takes up more room inside the wearer's waistband, decreasing comfort, and requiring the purchase of larger size pants. The same considerations are also important for strong side and crossdraw holsters worn outside the belt. They must hold the gun discreetly, securely, and comfortably, and they must provide immediate access to the gun when needed. They should allow for reholstering with one hand, in case only one hand is available for the task. Ideally, they should be reinforced at the lip sufficiently so that the holster retains it's shape regardless of whether or not it contains the gun, but the holster should not add significantly to the total thickness which must be concealed. Some holster makers have proposed the use of plastic instead of leather for holster construction, thereby providing rigidity without the necessity of using thick reinforcements. Such plastics, however, lack the aesthetic qualities of a molded leather holster. The best examples of current holsters and reinforcement methods are shown in the catalogs of several holster manufacturers. For example, a catalog for Bianchi International from 1996 shows an inside waistband holster having a swivel mounted belt loop, and two unreinforced inside waistband holsters. Second, a catalog for Milt Sparks Holsters, Inc. from 1996 shows several inside waistband holsters having metal reinforced front and sides, and interchangeable belt loops. One of these holsters has leather panels in front of and behind the gun pocket to enhance comfort, and another includes a waterproof membrane between layers of leather. Third, a catalog from Galco from 1997 shows an inside waistband holster positioned behind the small of the back for a cavalry-style twist draw, two inside waistband holsters having frontal and side reinforcement and interchangeable belt loops, one of which has a rear mounted belt loop, an inside waistband magazine pouch, a pair of unreinforced holsters, an inside waistband holster intended to fit totally below the waistband, and a holster having the belt clip attached to a leather flange protruding from the bottom of the holster, allowing the wearer to tuck in his shirt around the holster. Fourth, a catalog for Mitch Rosen from 1997 shows a variety of inside waistband holsters, all of which have front and side reinforcement. Most of them have rear mounted belt loops. One has a rear mounted belt loop in conjunction with a centrally mounted belt loop. Another has a leather panel extending below the barrel. One has its belt loop attached to a leather flange so that the wearer can tuck in his shirt around the holster. A catalog from Michaels of Oregon from 1997 shows an unreinforced nylon inside waistband holster, and a nylon police duty holster having a thermoplastic exoskeleton along the front, sides, and rear for reinforcement. Additionally, several patents show various proposed holster designs. For example, U.S. Pat. No. Des. 324,773, issued to Alan Baruch on Mar. 24, 1992, shows a design for a strong side belt holster having a thumb break safety strap with an additional safety strap securing the thumb break. U.S. Pat. No. 1,827,182, issued to Manuel M. Arias on Oct. 13, 1931, describes a revolver holster having a pair of loops on either side of the inside of the holster top. When the revolver is withdrawn, the cylinder catches on the loops, requiring a slight effort to withdraw the revolver. The loops thereby prevent loss of the revolver without the need for a safety strap. U.S. Pat. No. 4,303,185, issued to Loren R. Shoemaker on Dec. 1, 1981, describes a strong side belt holster having a vertical opening down the front of the holster, a pivot between the grip and trigger guard, and a thumb break safety strap. Drawing the pistol is accomplished by rotating the muzzle through the front opening and grip downward, bringing the pistol horizontal. U.S. Pat. No. 4,325,506, issued to James W. Lindell and Arthur F. Barnett on Apr. 20, 1982, describes a reinforcement for a holster. The reinforcement is a pliable material along the top of the outer and rear portions of the holster, and a rivet passing through both the pliable material on either side of the rear of the holster. U.S. Pat. No. 4,463,884, issued to Henry J. Parlante on Aug. 7, 1984, describes a security holster for a revolver. The holster has a W-shaped spring in front, pulling the two sides of the holster together, and the rear portion of the top, covering the trigger guard, is closed. This pushes the revolver rearward so that the revolver's trigger guard is underneath the closed portion of the holster top, preventing a person from removing the revolver by pulling it rearward. U.S. Pat. No. 4,645,103, issued to John E. Bianchi, Wayne B. Gregory, and Richard D. E. Nichols on Feb. 24, 1987, describes a holster having a body constructed from closed cell foam surrounded by nylon, a stiffening member forming a front sight channel, and a safety strap secured to the back of the holster by hook and loop fasteners, allowing the length and position of the safety strap to be adjusted to accommodate different handguns. This design, while good for its intended purpose as a belt holster, will not function as an inside waistband holster. A front stiffening member, by itself, will be insufficient to keep such a holster open when the gun is drawn, because the closed cell foam and nylon construction has insufficient rigidity to be held open merely by frontal reinforcement. U.S. Pat. No. 5,199,620, issued to Robert J. Beletsky on Apr. 6, 1993, describes a security holster. The holster has a safety strap with a thumb break. The thumb break rotates from a vertical position wherein it is used in the conventional manner to release the safety strap, and a horizontal position wherein it locks the safety strap in place. U.S. Pat. No. 5,201,447, issued to George Bumb and Gerald L. Campagna on Apr. 13, 1993, describes a holster having a paddle attached to the inside surface for holding the holster on the waistband of a wearer's pants, and a safety strap having two portions attaching to the holster using hook and loop fasteners. U.S. Pat. No. 5,209,383, issued to Paris Theodore on May 11, 1993, describes an upside-down shoulder holster, a belt holster, and a pocket holster, all having holster bodies constructed from one piece of material. U.S. Pat. No. 5,251,798, issued to Paris Theodore on Oct. 12, 1993, describes an upside-down shoulder holster, a belt holster, and a pocket holster, all having holster bodies constructed from one piece of material. U.S. Pat. No. 5,501,380, issued to Kuang-Li Wu on Mar. 26, 1996, describes a holster having a safety strap or flap secured around the handgun therein by a combination lock. U.S. Pat. No. 5,570,830, issued to Richard E. D. Nichols on Nov. 5, 1996, describes a holster having a rigid spine with vertical grooves on either side, and side panels fastened within those grooves. European Pat. App. No. 0,312,521, published on Apr. 19, 1989, appears to describe a strong side belt holster. Despite the wide variety of inside waistband holsters developed by other inventors, the vast majority are either totally unreinforced, allowing them to collapse when the gun is drawn so that two hands are required for reholstering, or have reinforcing which adversely affects the bulkiness and concealability of the holster. None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus a holster solving the aforementioned problems is desired. SUMMARY OF THE INVENTION The present invention is a molded leather holster having a reinforcement located at the front of the pocket's lip, with unreinforced sides. Such a reinforcement is particularly desirable with inside waistband holsters, and is also very useful for strong side belt holsters, crossdraw holsters, and other styles of holster. This frontal reinforcement is sufficient to keep the holster's pocket open under pressure, while placing all reinforcing material where it will not adversely affect the holster's concealability. The frontal reinforcement may be constructed in different ways. One preferred method is to construct a holster having a leather tongue extending from the front of the holster's top. Folding this tongue over the front of the holster, and gluing and stitching it in place, creates a particularly rigid reinforcement. Collapsing the pocket of such a holster would require folding the leather reinforcement perpendicular to the original fold, which is extremely difficult to accomplish. A second reinforcement is constructed by attaching a metal or plastic plate to the front of the holster. Either metal or plastic may be attached to the holster by stitching the plate between the holster's front and a leather reinforcement. Alternatively, a plastic plate may be stitched directly to the holster. One preferred style of an inside waistband holster using the current reinforcement attaches to the wearer's belt by means of a rear-mounted belt loop, attached to a flange extending beyond the rear of the holster. Mounting the belt loop to the rear of the holster pocket, instead of directly on it, decreases the overall thickness which must be concealed. Additionally, the belt loop may be positioned to hold the gun at any desired angle from vertical for maximum concealment or comfort, or exchanged for a belt loop of a different size to correspond to the size of the belt. The reinforcement may also be used with inside waistband holsters having centrally mounted belt loops. Such belt loops typically attach to the holster in the same manner as a rear mounted belt loop, with the only difference being the position of the belt loop. The centrally mounted loop has the advantage of more securely fixing the angle of the holster, and is more effective at holding the holster in position during a draw. The holster may include a rear flange to increase the bearing surface against the wearer, decreasing pressure points, or may omit this flap, decreasing the size of the holster which must fit within a wearer's waistband. Additionally, a second belt loop may be attached to a front flange, attaching to the front reinforcement. The front belt loop, like the rear belt loop, can be reversed for right or left side wear, or exchanged for a belt loop of a different size to correspond to the wearer's belt. The front flange may be permanently attached to the holster, or may be removably attached by means of a snap fastener on the reinforcement. The reinforcement may also be used for belt holsters, and works particularly well with a holster fastening to a belt using a loop and tunnel system. The weight of the gun and holster is supported by a tunnel mounted centrally on the holster body, and a belt loop cut through a rear flange serves to pull the gun's handgrip close to the body, maximizing concealment. With no belt loops attaching to the front of the holster, this holster design provides sufficient surface area for attaching the reinforcement. This holster design works well for both strong side and crossdraw holsters, the only difference between the two being the positioning of the belt loops so that the gun's muzzle points either straight down or slightly rearward for strong side hip holsters, or angled in the opposite direction for a crossdraw holster. Accordingly, it is a principal object of the invention to provide a holster which will not collapse when the gun is drawn, allowing for one-hand reholstering. It is another object of the invention to provide a holster having thin sides, so that it adds very little to the total thickness which must be concealed by the wearer. It is a further object of the invention to provide a holster which may be quickly configured for a right handed or left handed individual. Still another object of the invention is to provide a holster which allows the wearer to adjust the angle from vertical at which the gun is carried. It is an object of the invention to provide improved elements and arrangements thereof for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes. These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a first embodiment of an inside waistband holster according to the present invention, having a rear belt loop. FIG. 2 is an exploded view of a first embodiment of an inside waistband holster according to the present invention. FIG. 3 is a perspective view of a second embodiment of an inside waistband holster according to the present invention, having both front and rear belt loops. FIG. 4 is an exploded view of a second embodiment of an inside waistband holster according to the present invention. FIG. 5 is an exploded view of a second embodiment of an inside waistband holster according to the present invention, showing an alternative means of construction. FIG. 6 is an environmental, perspective view of a first embodiment of an inside waistband holster according to the present invention. FIG. 7 is a perspective view of a second embodiment of an inside waistband holster according to the present invention, showing the holster assembled for left-hand use. FIG. 8A is a top perspective view of a prior art holster. FIG. 8B is a top perspective view of a holster according to the present invention. FIG. 9 is a perspective view of a strong side belt holster according to the present invention, showing the side attaching to the wearer's belt. FIG. 10 is a perspective view of a strong side belt holster according to the present invention, showing the side away from the wearer's body. FIG. 11 is a perspective view of a crossdraw holster according to the present invention. FIG. 12 is a perspective view of an inside waistband holster according to the present invention, showing a holster having centrally mounted belt loops. FIG. 13 is a perspective view of an inside waistband holster according to the present invention, showing a holster having centrally mounted belt loops, and omitting the rear flange. Similar reference characters denote corresponding features consistently throughout the attached drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is a holster having a reinforced front and unreinforced sides. Such reinforcement is particularly suited to inside waistband holsters, but is also very helpful with strong side belt and crossdraw holsters. Referring to FIG. 1, a preferred style of inside waistband holster is illustrated. The holster 10 comprises gun pocket 12, having front 14, and sides 16,18. Ideally, holster pocket 12 will be made from rigid leather, molded to the size and shape of the gun to be carried. At the rear of gun pocket 12, sides 16 and 18 are joined together, and continue rearward to form rear flange 20. Rear belt loop 22a is secured in a closed position by snap 24a. Front reinforcement 26 is attached to the front 14 of pocket 12, but not to sides 16,18. Referring to FIG. 2, the individual components of holster 10 are illustrated. Reinforcement 26 is a tongue extending from the front 14 of holster 10, made from the same piece of leather. Reinforcement 26 is folded towards front 14, and glued and stitched into place. The snap 24a includes male snap component 28a, located at one end of belt loop 22a, and female snap component 30a, located at the opposite end of belt loop 22a. Belt loop 22a is attached to rear flange 20 by screw 32a, passing through male snap component 28a, through one of the two holes 44a, and into the internally threaded shaft 40a. Washer 34a, fitting between belt loop 22a and rear flange 20, has diagonally-oriented edges 36 to prevent belt loop 22a from spinning relative to rear flange 20. Washer 38a fits between screw 32a and male snap component 28a. Referring to FIG. 3, holster 10 may optionally include front belt loop 22b, attached to front flange 42. FIGS. 4 and 5 show alternative means of attachment for front flange 42, along with alternative methods of reinforcement, with FIG. 4 showing a detachable front flange 42 and FIG. 5 showing a permanently attached front flange 42. Referring to FIG. 4, belt loop 22b is attached to front flange 42 in a manner identical to the attachment of rear belt loop 22a to rear flange 20. Specifically, front belt loop 22b is attached to front flange 42 by screw 32b, passing through male snap component 28b, hole 44b, and into the internally threaded shaft 40b. Washer 34b, fitting between belt loop 22b and front flange 42, has diagonally-oriented edges 36 to prevent belt loop 22b from spinning relative to front flange 42. Washer 38b fits between screw 32b and male snap component 28b. Female snap component 46, located at one end of belt loops 22a and 22b, attaches to mating member 48 through hole 50. The front 14 of holster 10 includes reinforcement plate 52, made from plastic or metal, under reinforcement panel 54, made from leather. Reinforcement panel 54 is stitched to holster front 14, with the stitching surrounding plate 52. Male snap component 28 is attached to reinforcement plate 52, and mates with female snap component 56, attached to flange 42. Female snap component 56 attaches to mating member 57, joining through hole 58 in flange 42. Alternatively, reinforcement plate 52 may be stitched directly to holster 10, without the use of panel 54, if reinforcement plate 52 is made from leather instead of plastic. FIG. 5 illustrates an embodiment wherein front flange 42 is permanently stitched to the front 14 of holster 10. As in the previous embodiment, belt loop 22b is attached to front flange 42 in a manner identical to the attachment of rear belt loop 22a to rear flange 20. Specifically, front belt loop 22b is attached to front flange 42 by screw 32b, passing through male snap component 28b, hole 44b, and into the internally threaded shaft 40b. Washer 34b, fitting between belt loop 22b and front flange 42, has diagonally-oriented edges 36 to prevent belt loop 22b from spinning relative to front flange 42. Washer 38b fits between screw 32b and male snap component 28b. The front 14 of holster 10 includes reinforcement plate 52, made from plastic or metal, under reinforcement panel 54, made from leather. Reinforcement panel 54 is stitched to holster front 14, with the stitching surrounding plate 52. Front flange 42 is then stitched over panel 54. Alternatively, if plate 52 is made from plastic, it may be stitched directly to the holster 10 without the use of reinforcement panel 54. Front flange 42 is then stitched over plate 52. Referring to FIG. 7, any embodiments of this holster described above may be configured for right or left hand use. FIG. 7 illustrates the embodiment having a removably attached front flange, because it best illustrates the method of configuring all embodiments for weak hand use. Referring to FIGS. 4 and 7, snap 24a is unsnapped, and screw 32a is unscrewed. Belt loop 22a, along with washer 38a, male snap portion 28a, washer 34a, and threaded shaft 40a are removed from hole 44a in rear flange 20. If the width of the wearer's belt does not correspond with the opening in belt loop 22a, a different belt loop 22a may be substituted. The belt loop 22a, washers 38a and 34a, and male snap portion 28a are then moved from the side of flange 20 formed by holster side 16 to the side of flange 20 corresponding to holster side 18, while threaded shaft 40a is moved towards side 16. Threaded shaft 40a is inserted into one of the two holes 44a. If the wearer wants holster 10 to ride higher on the hip, the lower of the 2 holes 44a is used. If the wearer prefers that the holster ride lower, the higher of the two holes 44a is used. Washer 34a is placed over shaft 40a, followed by belt loop 22a, male snap portion 28a, washer 38a, and screw 32a. Screw 32a is tightened most of the way, and then the wearer rotates belt loop 22a around shaft 40a until the belt loop is properly angled relative to the vertical. The proper angle will depend entirely on the wearer's preference, and may be chosen to position the barrel vertical, to position the grips forward, or to position the muzzle forward. Screw 32a is tightened, causing edges 36 of washer 34a to bear against belt loop 22a and flange 20, holding the belt loop in the proper position. Likewise, front belt loop 22b may be positioned for right or left hand use. Front flange 42 is attached to the front 14 of holster 10 using mating snap portions 28c, 56. Snap 24b is unsnapped, and screw 32b is unscrewed. Belt loop 22b, along with washer 38b, male snap portion 28b, washer 34b, and threaded shaft 40b are removed from hole 44b in front flange 42. If the width of the wearer's belt does not correspond with the opening in belt loop 22b, a different belt loop 22b may be substituted. The belt loop 22b, washers 38b and 34b, and male snap portion 28b are then moved from the side of flange 42 corresponding to holster side 16 to the side of flange 20 corresponding to holster side 18, while threaded shaft 40b is moved towards side 16. Threaded shaft 40b is inserted into hole 44b. Washer 34b is placed over shaft 40b, followed by belt loop 22b, male snap portion 28b, washer 38b, and screw 32b. Screw 32b is tightened most of the way, and then the wearer rotates belt loop 22b around shaft 40b until the belt loop is properly angled relative to the vertical. The proper angle will depend entirely on the wearer's preference, and may be chosen to position the barrel vertical, to position the grips forward, or to position the muzzle forward. Screw 32b is tightened, causing edges 36 of washer 34b to bear against belt loop 22b and flange 20, holding the belt loop in the proper position. Referring to FIG. 6, the usual method of wearing an inside waistband holster is illustrated. Holster 10 is inside pants waistband 60, with belt loop 22a extending over the top of waistband 60, surrounding belt 62. The holster is thereby precluded from slipping further down within waistband 60, or from rising out of waistband 60. Holster 10 is preferably made from rigid leather molded to the shape of the specific handgun 64 for which the holster 10 was designed. Such a holster construction allows the holster to fit very tightly around the handgun 64, creating a high degree of friction between holster 10 and handgun 64, preventing the handgun from leaving the holster until the wearer pulls it out. With the holster worn in such a manner, FIGS. 8A and 8B illustrate how the present invention has a clear advantage over a prior art holster 68. As can be seen, the prior art holster reinforcement 66, illustrated in FIG. 8A, doubles the thickness of leather surrounding the handgun 64 as compared to the reinforcement 26 of the present invention, shown in FIG. 8B. The extra thickness which must fit within a pants waistband 60 while using a prior art holster creates a larger bulge, making concealment more difficult, and also takes up more space within the waistband, decreasing comfort. The reinforcement is not limited to inside waistband holsters, but is also useful for a wide variety of other styles of holster, such as strong side belt and crossdraw holsters. FIGS. 9 and 10 illustrate strong side belt holsters using the frontal reinforcement, while FIG. 11 illustrates a crossdraw holster using the reinforcement. The strong side belt holster of FIGS. 9 and 10 differs from the crossdraw holster of FIG. 11 only in the angle and positioning of the belt loop and tunnel, so these figures are best described together. Holster 70 has a gun pocket 12, having front 14 and sides 16,18. Ideally, gun pocket 12 will be made from rigid leather, molded to fit the gun to be carried. At the rear of gun pocket 12, sides 16 and 18 are joined together, and continue rearward to form rear flange 20. Rear belt loop 72 is cut through flange 20. Tunnel 74 is secured to side 18. Referring to FIGS. 9 and 10, a vertical rear belt loop 72 and tunnel 74 is a preferred configuration for a strong side belt holster. Referring to FIG. 11, a slanted belt loop 72, and a tunnel 74 positioned closer to muzzle portion 76 of side 18 and also slanted, will position gun pocket 12 diagonally across the wearer's body. This configuration is desirable for a crossdraw holster. Referring back to FIGS. 911, it is apparent that there are no obstructions on holster front 14 to preclude placement of reinforcement 26 at this location, as might exist with a pancake style holster. Front reinforcement 26 is attached to the front 14 of pocket 12, but not to sides 16,18. Front reinforcement 26 may be constructed exactly as shown in either FIG. 2 or FIG. 4. Referring to FIG. 2, reinforcement 26 is a tongue extending from the front 14 of holster 10, made from the same piece of leather. Reinforcement 26 is folded towards front 14, and glued and stitched into place. Alternatively, referring to FIG. 4, the front 14 of holster 10 includes reinforcement plate 52, made from plastic or metal, under reinforcement panel 54, made from leather. Reinforcement panel 54 is stitched to holster front 14, with the stitching surrounding plate 52. Reinforcement plate 52 may also be stitched directly to holster 10, without the use of panel 54, if reinforcement plate 52 is made from leather instead of plastic. FIGS. 12 and 13 show a different style of inside waistband holster which also benefits from the use of frontal reinforcement. Holster 78 has a gun pocket 12, having front 14 and sides 16,18. Ideally, gun pocket 12 will be made from rigid leather, molded to fit the gun to be carried. At the rear of gun pocket 12, sides 16 and 18 are joined together, and continue rearward to form rear flange 20. Rear flange 20 increases the surface area bearing against the wearer, decreasing the pressure. Alternatively, some users will prefer to omit rear flange 20 as shown in FIG. 13, reducing the size holster which must be worn within the waistband. Referring back to FIGS. 12-13, a pair of belt loops 80 are attached to side 16 at the point of snaps 82, in a conventional manner. Front reinforcement 26 is attached to the front 14 of pocket 12, but not to sides 16,18. Front reinforcement 26 may be constructed exactly as shown in either FIG. 2 or FIG. 4. Referring to FIG. 2, reinforcement 26 is a tongue extending from the front 14 of holster 10, made from the same piece of leather. Reinforcement 26 is folded towards front 14, and glued and stitched into place. Alternatively, referring to FIG. 4, the front 14 of holster 10 includes reinforcement plate 52, made from plastic or metal, under reinforcement panel 54, made from leather. Reinforcement panel 54 is stitched to holster front 14, with the stitching surrounding plate 52. Reinforcement plate 52 may also be stitched directly to holster 10, without the use of panel 54, if reinforcement plate 52 is made from leather instead of plastic. It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.	A holster having a reinforced front portion to prevent the holster from collapsing under pressure from the wearer's belt when the gun is drawn. The holster is preferably made from rigid leather, molded to conform to the specific gun intended to be carried. A rigid leather reinforcement, which may also include a metal or plastic plate, along only the front portion of the holster is sufficient to keep the holster open when the gun is drawn, without increasing the thickness of the holster, thereby maintaining concealability. This reinforcement is particularly desirable for inside waistband holsters. Such an inside waistband holster may have a single central or rearward belt loop, or a pair of belt loops, with one mounted in front and the other at the rear. The belt loops may be reversible for weak side wear. Additionally, the reinforcement may be used with strong side or crossdraw belt holsters.	5
BACKGROUND OF THE INVENTION [0001] This invention relates to excess flow valves for controlling flow through a conduit and more particularly to an excess flow valve that minimizes pressure drops within the valve through a simplified valve construction. [0002] Excess flow valves are utilized to limit the amount of fluid flow through a conduit. Generally, some way of holding the valve in a generally open position maintains the valve in an open position, allowing flow through the conduit if the flow rate through the conduit is below a predetermined limit. If the flow rate increases causing the pressure drop across the valve to exceed a certain value, then the valve is moved to a closed position restricting flow through the conduit. [0003] One type of excess flow valve uses a magnet to hold the valve at a generally open position. The typical prior art magnetic excess flow valve has been incorporated into a capsule, wherein the entire structure for providing a valve seat, a valve guide, and a magnet holder are all incorporated as a single capsule item. Ideally, any pressure drops across the valve will help close the valve. Prior art valve structures are inefficient, however, because the structures often interfere with fluid flow through the valve, causing excessive pressure drops that do not aid in closing the valve. Further, even though magnets should have sufficient force to re-open a closed valve, current magnet structures may not always have force characteristics that also allow the attractive force to be minimized in the open position to improve the sensitivity of the valve plate for valve closing. [0004] In addition, prior art valves have had non-symmetric structures, making valve operation dependent on the orientation between valve components. This causes the pressure drop required to close the valve to be, undesirably, a function of both the valve's component orientation and the flow rate rather than a function of the flow rate alone. When fluid pressure drops are a function of the orientation of components within the valve as well as fluid flow, the valve operation becomes unpredictable. [0005] There is a desire for an excess flow valve structure that does not interfere with fluid flow and responds accurately and consistently to fluid pressure drops in a conduit. [0006] There is also a desire for an excess flow valve structure that optimizes pressure drops to maximum valve efficiency while still maintaining a desired valve closure flow rate. SUMMARY OF THE INVENTION [0007] Accordingly, one embodiment of the invention is directed to a simplified excess flow valve structure that improves the efficiency of valve operation by ensuring that any pressure drops across the valve aid closing of the valve. This is achieved by reducing the number of valve parts, minimizing flow restrictions through the conduit due to the valve assembly to the extent possible when the valve is open. In one embodiment, a valve body portion incorporating a valve guide and a magnet holder is separate from the valve seat. In some embodiments the valve seat may be provided by a separate valve seat component, and in other embodiments the valve seat is integrated into a conduit structure. [0008] In another embodiment, the valve is mounted at an interface between two conduit portions. In this embodiment, there is less structure at the outer periphery of the valve to disrupt or otherwise restrict fluid flow. The excess flow valve allows fluid to flow around the outer periphery of the valve plate when the valve plate in the valve is in its open position. The inventive structure therefore avoids fluid flow obstacles that cause unnecessary pressure drops in the valve. In a further embodiment, the valve has a disk-shaped magnet rather than a cylindrical magnet, improving the force characteristics of the magnet and minimizing the attractive force in the open position to improve the sensitivity of the valve plate for valve closing. [0009] By minimizing undesirable flow restrictions in the valve, the inventive structure improves valve efficiency, allowing a minimal valve size for a desired flow rate. The inventive structure also eliminates orientation-specific flow restrictions, ensuring that fluid pressure drops through the valve are caused only by the flow rate and not component orientation, thereby providing consistent efficiency and valve closure flow rates. BRIEF DESCRIPTION OF THE DRAWINGS [0010] [0010]FIG. 1 is a section view taken along line 1 - 1 ′ of one embodiment of the inventive valve as shown in FIG. 4. [0011] [0011]FIG. 2 is a compound section view taken along line 2 - 2 ′ in FIG. 4. [0012] [0012]FIG. 3 is a perspective view of the valve shown in FIG. 1. [0013] [0013]FIG. 4 is plan view of the valve shown in FIGS. 1 and 2. [0014] [0014]FIG. 5 illustrates another embodiment of the invention having a valve seating structure integrated into a conduit. [0015] [0015]FIG. 6 is a sectional view of the invention shown in FIG. 5. [0016] [0016]FIG. 7 is a sectional view of yet another embodiment of the present invention. [0017] [0017]FIG. 8 is a representative diagram of a magnet according to one embodiment of the invention. DETAILED DESCRIPTION OF THE EMBODIMENTS [0018] Referring to FIGS. 1 through 4, an excess flow valve 20 is positioned within a conduit 22 . In this embodiment, a valve seat component 26 is provided as a separate element from a valve body 27 in the excess flow valve 20 . The valve seat 26 may be made of a resilient material to create a fluid-tight seal. An outer surface 28 of the valve seat 26 engages the inner surface of the conduit 22 . An outer peripheral portion 30 of the valve body 27 is ring-shaped and also engages the inner surface of the conduit 22 . The valve body 27 in this embodiment also includes an inner hub 32 supported by a first set of arms 33 extending between the outer peripheral portion 30 and the inner hub 32 . In one embodiment, the arms have a axial portion 33 a and a radial portion 33 b. Guide protrusions 35 on the arms 33 form a magnet retention structure to hold a magnet 34 , preferably a disk-shaped magnet. Note that the inner hub 32 is an optional structure; if the inner hub 32 is eliminated, the arms 33 may intersect somewhere inside the boundaries of the outer peripheral portion 30 at a central point. Alternatively, the arms 33 may be linked to each other in some other fashion. The arms 33 may also not contact each other at all and be attached only to the outer peripheral portion 30 . The arms 33 may also be configured so that they cannot open out in a radial direction, ensuring that the magnet 34 is retained firmly in the valve 20 . [0019] A disk-shaped valve plate 40 is movable between an open position, where the valve plate 40 moves toward the magnet 34 , and a closed position, where the valve plate moves toward the valve seat 26 to close the conduit 22 . FIGS. 1 through 3 show the valve plate 40 in an open position. The circumferential edge of the valve plate 40 and the inside surface of the conduit 30 form a fluid path (shown in FIG. 1 by arrow A) that is unobstructed by any portion of the valve body 27 when the valve plate 40 is in the open position. As shown in the Figures, the plate 40 sits slightly upstream of the outer peripheral portion 30 while still being guided by the axial portion 33 a of the arms 33 when in the open position, leaving a gap 41 through which fluid can flow easily between the plate 40 and the conduit 22 . Although the arms 33 do act as a minor obstacle in the fluid path, the effect of the arms 33 on fluid flow is minimal because the circumference of the valve plate 40 is otherwise free, without any portion of the valve body 27 surrounding the plate 40 when the plate 40 is in the open position. [0020] The disk-shaped valve plate 40 is preferably symmetrical so that the valve plate's 40 orientation with respect to the hub 32 and arms 33 does not affect the fluid flow through the conduit 22 . In one embodiment, the arms 33 act as a guide for the valve plate 40 as well as a magnet holder, eliminating the need for separate guiding structures on the valve plate 40 itself. [0021] As noted above, the first set of arms 33 connect the outer peripheral portion 30 of the valve 20 with the inner hub 32 . One embodiment of the inventive valve structure 20 may also include an optional second set of arms 42 that extend outwardly and radially from the inner hub 32 and end between the inner hub 32 and the outer peripheral portion 30 . The additional arms 42 distribute additional contact points to guide the valve plate 40 while still minimizing the total contact surface between the plate 40 and the arms 33 , 42 , preventing the plate 40 from being stuck in a tilted position (e.g., with one portion of the plate 40 lying farther upstream than other portions of the plate 40 ) within the valve body 27 . In one embodiment, the first and second arms 33 , 42 alternate around the inner hub 32 to distribute the contact points evenly on the plate 40 . Further, because the arms 33 , 42 are arranged to minimize the area of the plate 40 contacting the arms 33 , 42 , the inventive structure maximizes the area of the plate 40 facing the upstream side of the conduit 22 . [0022] To minimize the contact between the valve plate 40 and the arms 33 , 42 , contact pads 43 may be formed in either or both sets of arms 33 , 42 . The pads 43 extend slightly from the arms 33 , 42 and act as point contacts on the plate 40 surface. Alternatively, the arms 33 themselves may extend upstream and emanate inwardly from the outer peripheral portion 30 of the valve body 27 to form contact pads 43 at the point where the outer peripheral portion 30 and the arms 33 join. Regardless of the pad 43 structure, the pads 43 minimize contact between the plate 40 and the arms 33 , 42 or any other portion of the valve body 27 . In one embodiment, the pads 43 contact less than 10%, and preferably around 2%, of the plate 40 surface. [0023] To hold the magnet 34 more securely, the valve body 27 may include a magnet retention structure that positions the magnet 34 upstream of the valve plate 40 . In one embodiment, one or more of the arms 33 , 42 may include a clip portion 44 to form the magnet retention structure. The magnet 34 may then be engaged with the clip portions 44 during valve assembly. The thin profile of the disk-shaped magnet 34 allows it to be held firmly in the valve 20 without requiring bulky attachment structures that would interfere with fluid flow. In the illustrated embodiments, the clip portions 44 are placed on the second set of arms 42 , but they may also be formed on first set of arms 33 instead of or in addition to the guide protrusions 35 . [0024] Shaping the magnet 34 into a disk rather than a cylinder further reduces the amount of space that the valve 20 occupies in the conduit 22 . The clip portions 44 create a positive engagement between the arms 33 , 42 and the magnet 34 , ensuring that the magnet 34 will not be partially inserted or jarred out of position during shipping. [0025] The magnet 34 is preferably magnetized across a face surface 46 of the magnet 34 (i.e., wherein the poles lie radially opposite each other), as shown in FIG. 8, rather than magnetized parallel to the fluid flow because the thin profile of the magnet 34 makes magnetizing in the axial direction impractical. In other words, the north and south poles of the magnet 34 would each be on the outer perimeter of the face surface 46 across from each other. In one embodiment, the center of the face surface 46 is left unmagnetized, acting as a transition zone between the north and south poles of the magnet 34 . A disk-shaped magnet has a more desirable force characteristic than a cylindrical magnet due to the disk-shaped magnet's greater diameter-to-thickness ratio. This improved force characteristic provides a more constant magnet force attracting the valve plate 40 as it travels between the open and closed positions. To control the overall magnet strength after selecting the optimal magnet shape, inert material may be added into the magnet 34 . [0026] Note that the magnet 34 does not necessarily have to be disk-shaped; any magnet 34 having radially opposed poles will have characteristics that are advantageous in the inventive structure. For example, the magnet 34 may be shaped as a cylinder, but magnetized with radially opposed poles. The magnet 34 may also be formed in an annular shape, with a hole in the center of the magnet 34 that can provide an additional fluid flow path through the middle of the valve 20 . Regardless of the actual magnet shape, the radially opposed poles provide improved force characteristics over magnets that are magnetized parallel to fluid flow. [0027] [0027]FIG. 5 is an exploded view illustrating one embodiment of the excess flow valve 20 incorporated into a two-piece conduit, while FIG. 6 is a section view taken along line 6 - 6 ′ of FIG. 5. First and second conduit portions 50 , 52 are coupled together via a threaded connection 60 and a valve seat 64 is formed as an integral part of the conduit 22 rather than a separate component. An opposed end surface 66 of the second conduit portion 52 captures the valve body 27 . While the valve 20 is shown axially captured in the figure, the outer periphery of the valve body 27 could also be formed to be an interference fit within the conduit 22 . [0028] The valve body 27 holds the magnet 34 adjacent the valve plate 40 . As shown in FIG. 6, the valve body 27 does not have material disposed around its entire circumference to hold the magnet 34 and guide the valve plate 40 . Instead, as noted above, the first and second sets of arms 33 , 42 are circumferentially spaced to reduce resistance to fluid flow past the valve 20 . [0029] [0029]FIG. 7 illustrates another embodiment of the present invention. In this embodiment, the excess flow valve 20 is designed to fit inside a conduit 70 having a threaded area 72 at the end of the conduit 70 such that the valve seat 26 terminates at or near the end of the threaded area 72 . [0030] Although the valve structure focuses on guiding the valve plate 40 and supporting the magnet 34 with arms, other valve plate guide and/or support structures may be incorporated into the valve body 27 without departing from the scope of the invention. [0031] As a result, the inventive structure improves valve operation by incorporating a disk-shaped magnet in the valve and a disk-shaped valve plate that is guided by the valve body instead of protrusions on the valve plate itself. Further, the outer peripheral portion is formed on the valve body so that the circumference of the valve plate is not enclosed by the outer peripheral portion when the valve plate is in the open position, leaving the valve plate edge exposed to form a fluid path defined by the valve plate and the inside surface of the fluid conduit instead of the valve plate and the valve body. By minimizing fluid path obstructions, minimizing contact between the valve plate and the valve body, and taking advantage of the force characteristics of the disk-shaped magnet, the inventive excess flow valve offers improved valve efficiency. [0032] It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that the method and apparatus within the scope of these claims and their equivalents be covered thereby.	A number of improved excess flow valves are disclosed wherein pressure drop is optimized through the device to maximize efficiency while minimizing shut-off flow rates. Flow restrictions are minimized throughout the valve structure and maximized across a valve closure plate, eliminating flow restriction variations caused by orientation of the valve components. A magnet having radially opposing poles optimizes the magnet's attractive force relationship with the valve plate.	8
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This is a divisional application of U.S. patent application Ser. No. 11/845,683, filed Aug. 27, 2007, which claims priority to U.S. Provisional Application Ser. No. 60/840,467, filed on Aug. 28, 2006, the entire disclosures of which are hereby incorporated by reference. FIELD OF THE INVENTION [0002] The present invention relates to high strength surgical suture materials, and more particularly to braided suture blends of ultrahigh molecular weight polyethylene coated with RGD peptide. DESCRIPTION OF THE RELATED ART [0003] Suture strength is an important consideration in any surgical suture material. One of the strongest materials currently formed into elongated strands is an ultrahigh molecular weight long chain polyethylene, typically used for fishing line and the like, which is sold under the trade names Dyneema or Spectra. This material is much stronger than ordinary surgical suture, however, it does not have acceptable knot tie down characteristics for use in surgical applications. BRIEF SUMMARY OF THE INVENTION [0004] The present invention advantageously provides a high strength surgical suture material with improved tie down characteristics. The suture features a braided jacket made of ultrahigh molecular weight fibers. The suture is coated with arginine-glycine-aspartate (RGD) peptide. The ultrahigh molecular weight polyethylene provides strength. Polyester fibers woven with the high molecular weight polyethylene provide improved tie down properties. RGD peptide promotes cell adhesion to substrates in vivo by interacting with receptors, integrins, on cell surface proteins. Further, RGD peptides also increase the permeability of endothelial monolayers and therefore may aid in surgical applications. [0005] In a preferred embodiment, the suture includes a multifilament jacket formed of ultrahigh molecular weight polyethylene fibers braided with polyester. The jacket surrounds a fiber core made substantially or entirely of ultrahigh molecular weight polyethylene. The core preferably includes three strands of ultrahigh molecular weight polyethylene, twisted at about three to six twists per inch. [0006] The jacket preferably comprises eight strands of ultrahigh molecular weight polyethylene braided with six strands of polyester. The tinted strands can be included in black or some other contrasting color. [0007] Ultrahigh molecular weight polyethylene fibers suitable for use in the present invention are marketed under the Dyneema trademark by Toyo Boseki Kabushiki Kaisha, and are produced in the U.S. by Honeywell under the trademark Spectra. [0008] The suture of the present invention advantageously has the strength of Ethibond No. 5 suture, yet has the diameter, feel and tie-ability of No. 2 suture. As a result, the suture of the present invention is ideal for most orthopedic procedures such as rotator cuff repair, Achilles tendon repair, patellar tendon repair, ACL/PCL reconstruction, hip and shoulder reconstruction procedures, and replacement for suture used in or with suture anchors. [0009] The suture is coated with RGD peptide. RGD peptide suitable for use in the present invention is marketed under PCI-36xx-PI by Peptides International, and under GRADSP peptide and GRGDSP peptide by Calbiochem. Other products suitable for use in the present invention marketed by Pierce are: (i) Product #28390—BupH MES Buffered Saline Packs to make a 500 ml of 0.1 M 2-[morpholino]ethanesulfonic acid, 0.9% NaCl, pH 4.7 when dissolved in 500 ml deionized water (5 liters total); (ii) Product #22980—1-Ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride (EDC or EDAC), a zero-length crosslinking agent used to couple carboxyl groups to primary amines and a water-soluble carbodiimide for rapid preparation of peptide conjugates; (iii) Product #24510—N-hydroxysulfosuccinimide (Sulfo-NHS), a product useful in improving the efficiency of EDC coupling. [0010] A trace thread or two in the suture jacket aids surgeons in identifying the travel direction of the suture during surgery, particularly during operations viewed arthroscopically or remotely. Providing the trace threads in a regularly repeating pattern is particularly useful, allowing the surgeon to decode different ends of a length of suture, and to determine the direction of travel of a moving length of suture. The trace threads preferably are provided uniquely on each half of a length of suture to allow for tracing and identification of each end of the suture, such as when the suture is threaded through an eyelet of a suture anchor. [0011] Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0012] FIG. 1 is a copy of a scanning electron micrograph of a length of suture according to the present invention. [0013] FIG. 2 is a schematic cross section of a length of suture according to the present invention. [0014] FIG. 3 is an illustration of the suture of the present invention attached to a suture anchor loaded onto a driver. [0015] FIG. 4A and 4B show the suture of the present invention attached to a half round, tapered needle. DETAILED DESCRIPTION OF THE INVENTION [0016] The term “yarn(s),” as used herein, is to be understood as including fiber(s), filament(s), and the like used to make a suture of the present invention. Typically, though, yarns are comprised of fibers and/or filaments. [0017] Referring to FIG. 1 , a scanning electron micrograph of a length of suture 2 according to the present invention is shown. Suture 2 is made up of a jacket 4 and a core 6 surrounded by the jacket 4 . See FIG. 2 . Strands of ultrahigh molecular weight polyethylene (UHMWPE) 8 , such as that sold under the tradenames Spectra and Dyneema, strands of polyester 10 , and tinted strands 12 are braided together to form the jacket 4 . Core 6 is formed of twisted strands of UHMWPE. [0018] UHMWPE, used for strands 8 , is substantially translucent or colorless. The polyester strands 10 are white (undyed). Due to the transparent nature of the UHMWPE, the suture takes on the color of strands 10 and 12 , and thus appears to be white with a trace in the contrasting color. [0019] In accordance with the present invention, trace strands 12 are preferably provided in black. The black trace assists surgeons in distinguishing between suture lengths with the trace and suture lengths without the trace. Traces also assist the surgeon in identifying whether the suture is moving. The trace can extend the entire length of the suture or only on half of a length of suture, the other half of the suture length remaining plain (white). Alternatively, the traces can form visibly distinct coding patterns on each half of the suture length. As a result, when the suture is threaded through the eyelet of a suture anchor, for example, the two legs (halves) of the length of suture are easily distinguished, and their direction of travel will be readily evident when the suture is pulled during surgery. [0020] Details of the present invention will be described further below in connection with the following examples: Example USP Size 5 (EP size 7) [0021] Made on a 16 carrier Hobourns machine, the yarns used in the braided jacket are Honeywell Spectra 2000, polyester type 712, and nylon. The jacket is formed using eight strands of 144 decitex Spectra per carrier, braided with six strands of 100 decitex polyester, and two strands of tinted nylon. The core is formed of three carriers of 144 decitex Spectra braided at three to six twists per inch. A No. 5 suture is produced. [0022] To make various sizes of the inventive suture, different decitex values and different PPI settings can be used to achieve the required size and strength needed. In addition, smaller sizes may require manufacture on 12 carrier machines, for example. The very smallest sizes can be made without a core. Overall, the suture may range from 5% to 90% ultrahigh molecular weight polymer (preferably at least 40% of the fibers are ultrahigh molecular weight polymer), with the balance formed of polyester and/or nylon. The core preferably comprises 18% or greater of the total amount of filament. [0023] The suture is coated with RGD peptide (PCI-36xx-PI). The RGD peptide-coating increases permeability of endothelial monolayers, thereby resulting in a decrease in abrasion resistance to the suture. RGD peptides promote cell adhesion to substrates in vivo by interacting with receptors, integrins, on cell surface proteins and thus, RGD peptide-coated sutures perform better than other sutures in surgical applications. [0024] Peptides may be coupled to or adsorbed to the suture. Typically, about 500 ml of coupling buffer, e.g., about 0.1M MES buffer, is prepared and a base, for example NaOH, is used to lower the acidity of the coupling buffer to a pH value of about 6.0. [0025] In one embodiment of the present invention, peptides are coupled to a suture. For coupling peptides to a suture, the suture is cut into 6 inch strips and soaked into an MES buffer for at least 30 minutes. Later, acid hydrolysis is performed, i.e., the suture is taken from the MES buffer and quickly dipped into an acid medium, for example, about 15 ml of 6N HCl and about 200 ul of H 2 O 2 . Thereafter, the suture is immediately put back into the MES buffer and washed several times. EDC and sulfo-NHS buffers are added to the MES buffer, for example, about 36 mg of EDC and about 99 mg of sulfo-NHS is added to about 90 ml of MES buffer. [0026] The suture is removed from the MES buffer and placed into the EDC buffer for about 15 minutes. The suture is then washed three times with the MES buffer. About 2 ml of peptide solution is immediately prepared and the suture immersed in the peptide solution. The peptide is allowed to react on the suture at 4° C. The suture is then washed about five times with MES buffer and then allowed to air dry under a hood. [0027] In another embodiment of the present invention, peptides are adsorbed to a suture. For adsorbing peptides to a suture, the suture is cut into 6 inch strips and soaked in a MES buffer for at least 30 minutes. Later, the suture is taken out and immediately placed back into the MES buffer and washed about three times. About 2 ml of peptide solution is immediately prepared and the suture immersed in the peptide solution. The peptide is allowed to react on the suture at 4° C. The suture is then washed about five times with MES buffer and then allowed to air dry under the hood. [0028] In an alternative embodiment of the present invention, a partially bioabsorbable suture is provided by blending a high strength material, such as UHMWPE fibers, with a bioabsorbable material, such as PLLA or collagen, for example. Accordingly, a suture made with about 10% Spectra or Dyneema blended with absorbable fibers would provide greater strength and with less stretch. Over time, 90% or more of the suture would absorb, leaving only a very small remnant of the knot. The absorbable suture can include coatings, for example collagen. [0029] The ultra high molecular weight (UHMW) polymer component of the present invention provides strength, and the polyester component is provided to improve tie ability and tie down characteristics. However, it has been found that the UHMW polymer provides an unexpected advantage of acting as a cushion for the polyester fibers, which are relatively hard and tend to damage each other. The UHMW polymer prevents breakage by reducing damage to the polyester when the suture is subjected to stress. [0030] In one method of using the suture of the present invention, the suture 2 is attached to a suture anchor 14 as shown in FIG. 3 (prepackaged sterile with an inserter 16 ), or is attached at one or both ends to a half round, tapered needle 18 as shown in FIGS. 4A and 4B . FIG. 4A also illustrates a length of suture having regularly repeating pattern of trace threads according to the present invention. Sections of the length of suture 2 have tinted tracing threads woven in. The alternating patterned and plain sections aid the surgeon in determining the direction of suture travel when pulling the suture, for example. [0031] Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art.	A high strength surgical suture material with improved tie down characteristics and tissue compliance formed of ultrahigh molecular weight polyethylene (UHMWPE) yarns, the suture being coated with arginine-glycine-aspartate (RGD) peptide. The suture has exceptional strength, is ideally suited for most orthopedic procedures, and can be attached to a suture anchor or a curved needle.	3
CROSS REFERENCE TO RELATED APPLICATIONS This application claims benefit to provisional application No. 61/673,040, filed on Jul. 18, 2012, which is incorporated by reference herein in its entirety. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OF DEVELOPMENT (Not Applicable) THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT (Not Applicable). INCORPORATION-BY-REFERENCE OF MATERIAL (Not Applicable). STATEMENT REGARDING PRIOR DISCLOSURES BY THE INVENTOR (Not Applicable). BACKGROUND OF THE INVENTION The present invention relates to a tethered helicopter surveillance system, and more particularly, to a system with a helicopter tethered by cable for data transfer. In the past, it has been proposed to mount a camera on helicopters and to control the position and attitude of the helicopters so that the line of sight of the camera, usually a television camera, is accurately positioned in space. This prior proposal suffers from the disadvantage that it is virtually impossible to angularly stabilize a rotating helicopter sufficiently to meet the image clarity and resolution requirements of a camera mounted thereon. Applicants have overcome these disadvantages by isolating the camera from the helicopter and mounting the camera on a gyroscopically stabilized platform whilst permitting the helicopter to move in angular attitude relatively thereto. In this invention, the surveillance system is generally equipped with a helicopter with at least one propeller or rotor allowing vertical takeoff and hovering; a camera or sensor system for gaining useful information relative to the helicopter's immediate surroundings as well as the land, sea and sky area within sight of the aircraft; and a tethered cable for transferring information to the ground station. Such a system is useful where it is desirable to observe surrounding areas, such as in reconnaissance by field troops, or in civilian work that requires observation from a distance. BRIEF SUMMARY OF THE INVENTION The invention aims to transfer a substantial volume of high-quality, high-volume real-time digital data, between a mobile airborne observation platform with a media converter, which is gyroscopically stabilized in a helicopter, and the ground control station via a tethered fiber connection and a fiber optic rotary joint between said platform and said ground station. The fiber-optic rotary joints allow for free rotation of fiber while maintaining excellent coupling efficiency. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING FIG. 1 : A schematic representation depicting certain principles of operation of the present invention. DETAILED DESCRIPTION OF THE INVENTION The helicopter may take a variety of shapes and sizes. A single main rotor shape such as is shown in FIG. 1 is quite suitable, although helicopters having other configurations (such as tandem rotor helicopters, Quadrotor helicopters, and other types of multicopter) could be utilized. The power sources of the helicopter include battery, solar, line power, gen-set, and gas. The tethered cable includes an optical fiber, an electrical wire (if needed), and/or other media transfer wires. FIG. 1 illustrates, schematically, the surveillance helicopter ( 5 ) being utilized. A gyroscopically stabilized platform ( 4 ) is attached underneath of the helicopter ( 5 ). The camera and/or sensor system with media converters is located within the gyroscopically stabilized platform ( 4 ). A cable ( 2 ) connects the gyroscopically stabilized platform ( 4 ) to the ground station ( 1 ) for data and/or power transfer, which is supported by way of harness lines ( 3 ). The cables ( 2 ) do not produce any force on the helicopter ( 5 ) The ground station may include a fiber rotary joint, an electrical slip ring, a cable reel, media converters, control system, and any number of additional equipment needed for the safe and effective control of the helicopter, the camera and any other sensors. The fiber optic rotary joint IS a mean to pass signals across rotating interfaces, particularly when transmitting large amounts of data. These signals can carry video, audio, data, control, power, or other information. Fiber rotary joint allows for free rotation of fiber while maintaining excellent coupling efficiency, because no physical contact occurs between two aligned fibers. Media converters are also called fiber links, fiber modems, fiber transmitters/receivers, or transceivers. They convert video, audio, data, or control signals (analog or digital) into optical signals, which are then converted back to electrical signals at the remote end. In operation, the helicopter ( 5 ) lifts up all the components of the invention, except the ground station ( 1 ), to a certain altitude while the cable ( 2 ) is connected to the ground station ( 1 ). The camera and/or sensor system, locating within the gyroscopically stabilized platform ( 4 ) captures useful information relative to the helicopter's immediate surroundings. All the information is converted by media converters and transferred from the camera and/or sensor system to the ground station ( 1 ) through the cable ( 2 ) in real time. Furthermore, the transitional terms “comprising”, “consisting essentially of” and “consisting of”, when used in the appended claims, in original and amended form, define the claim scope with respect to what unrecited additional claim elements or steps, if any, are excluded from the scope of the claim(s). The term “comprising” is intended to be inclusive or open-ended and does not exclude any additional, unrecited element, method, step or material. The term “consisting of” excludes any element, step or material other than those specified in the claim and, in the latter instance, impurities ordinary associated with the specified material(s). The term “consisting essentially of” limits the scope of a claim to the specified elements, steps or material(s) and those that do not materially affect the basic and novel characteristic(s) of the claimed invention. The supported, mixed metal oxide catalyst, its methods of preparation and use can in alternate embodiments, be more specifically defined by any of the transitional terms comprising”, “consisting essentially of” and “consisting of”.	The invention aims to transfer a substantial volume of high-quality, high-volume real-time data, which currently cannot be achieved by wireless techniques, between a mobile airborne observation platform and the ground station via a tethered fiber connection between said platform and said ground station.	1
BACKGROUND OF INVENTION [0001] The present invention relates to the balancing of fuel among tanks in a circulating fuel system mounted on a vehicle or other fuel consuming systems with multiple tanks. More specifically flow restriction devices on the fuel flow out of and into each tank are used to balance stored fuel among a number of tanks. The level of fuel in a tank controls the flow restriction devices. PRIOR ART [0002] Circulating fuel supply systems that include multiple fuel tanks are known and are typically used with vehicles. When applied to a vehicle the typical circulating fuel system includes at least two fuel tanks, a fuel pump, and an engine with a fuel supply rail. In operation, the fuel pump draws fuel from the tanks, and pumps the fuel to the fuel supply rail of the engine. The engine consumes some of the fuel. Unconsumed fuel leaves the engine and is returned to the fuel tanks. Thus, fuel is in constant circulation out of and back into the fuel tanks. [0003] As typically used with vehicles the tanks of a circulating fuel system are initially full of fuel. As the vehicle operates, fuel is drawn from the tanks. An engine consumes some of the fuel and any unconsumed fuel is returned to the tanks. Overall stored fuel decreases; however, if the fuel draw and return are not equal for each tank, then the quantity of fuel in the tanks will vary over time. Geometric or mechanical layout differences in tank, draw conduit, and return conduit, or changes in grade during vehicle operation make equal fuel draw and return practically unrealistic. Premature depletion of fuel in a tank relative to other tanks typically results in fuel starvation and engine operational problems. [0004] Unequal fuel draw and return results in the problem of one tank emptying before the others. This unequal depletion of fuel in the various tanks leads to erratic engine operation or fuel starvation. Various solutions have been proposed to balance the fuel in the tanks and to avoid the problems associated by unequal depletion of fuel from the multiple tanks. The known solutions in the prior art include the use of equal tank and conduit geometry, the use of one or more crossover lines, a venturi device, multiple pumps, special flow dividers, shuttle valves, a priming fuel line, or a complicated computer control system which requires an on-board computer and a electrical system for operation. The applications of these various solutions are described in a number of patents. [0005] The present invention balances the fuel in multiple fuel tanks through the use of flow restriction devices in both the draw and return conduits in each tank. As compared with prior inventions, the present invention eliminates the need for similar geometry of the tanks and conduits and their physical layout, crossover lines, more than one fuel pump, a venturi device, special flow dividers, shuttle valves, a priming fuel line, a computer, or an electrical system as needed to operate the computer. SUMMARY OF INVENTION [0006] An object of the present invention is to provide an apparatus and a method for the balancing of fuel between the various tanks in a multiple tank circulating fuel system. The present invention as applied to vehicles is a circulating fuel system, which includes at least two tanks, a pump which draws fuel from the tank, and an engine which receives fuel from the pump and consumes part of the fuel. Unconsumed fuel is returned to the tanks. The invention satisfies the objective by having a fuel level detection system, a draw conduit restriction device, and a return restriction device for each tank. [0007] In the method of the present invention, the level of fuel in each tank is balanced by detecting the level of fuel in the tank, and then restricting the flow of fuel out of the tank through the draw conduit and restricting the flow of fuel into the tank through the return conduit based on the detected fuel level. DRAWINGS [0008] [0008]FIG. 1 illustrates a circulating fuel system with flow restriction devices in both the draw and return conduits. [0009] [0009]FIG. 2 illustrates a float and a float arm mechanism for the control of both the draw and return flow restriction devices. [0010] [0010]FIG. 3 illustrates a float and a twisted guide mechanism to control gates which restrict both the draw and return fuel flow. [0011] [0011]FIG. 4 illustrated the use of a caged floatball device on the draw conduit and a caged floatball device on the return conduit to restrict the fuel draw and fuel return respectively. [0012] [0012]FIG. 5 illustrates a float and a gear mechanism to control gates which restrict both the draw and return fuel flow. [0013] [0013]FIG. 6 illustrates a vehicle with dual fuel tanks of a circulating fuel system mounted to the main rail of the chassis. DETAILED DESCRIPTION OF THE INVENTION [0014] The present invention uses flow restriction devices attached to both the draw and the return conduits of individual fuel tanks to balance the quantity of fuel in the fuel tanks of a circulating fuel system. The explanation of this invention begins with a description of the circulating fuel system with multiple fuel tanks. As shown in FIG. 1, a typical circulating fuel system includes a first tank 30 and a second tank 31 . The first and second tanks 30 and 31 contain draw conduits 40 and 41 , respectively. The draw conduits 40 and 41 combine into an inlet 42 of the fuel pump 20 . The fuel pump discharge 15 connects the fuel pump 20 to the engine 10 . In a typical engine the fuel flows through a fuel rail (not shown). A fuel conduit 52 connected to the engine 10 splits into return conduits 50 and 51 which in turn are connected to tanks 30 and 31 , respectively. [0015] The draw conduit 40 in the first tank 30 contains a draw restriction device 90 . Similarly, the return conduit 50 in the first tank 30 contains a return restriction device 100 . Restriction devices, 90 and 100 , connect to a float 70 through a float arm mechanism 60 . Similarly, the draw conduit 41 and the return conduit 51 in the second tank 31 contain corresponding restriction devices 91 and 101 . These flow restriction devices are connected to a float 71 through a float arm mechanism 61 . [0016] In operation, fuel in tanks 30 and 31 is drawn into the draw conduits 50 and 51 , respectively. The fuel flows past the draw restriction devices, 90 and 91 , which control the relative, flow of fuel out of fuel tanks 30 and 31 , respectively. The draw restriction devices 90 and 91 are controlled based on fuel levels 80 and 81 through respective float arm mechanisms 60 and 61 and floats 70 and 71 . At a low fuel level in either tank 30 or 31 the draw restriction devices 90 or 91 , which are respectively controlled through float arm mechanisms 60 and 61 , restrict the flow of fuel from the corresponding fuel tank 30 or 31 . The restriction of fuel flow from tanks 30 and 31 decreases as the fuel level in the tank increases. [0017] Once past the draw restriction devices 90 and 91 , the fuel flows out of the draw conduits 50 and 51 and combines in the fuel pump inlet 42 . The combined fuel is drawn into the fuel pump 20 , which provides the suction to draw the fuel from the fuel tanks 30 and 31 . From the fuel pump 20 the fuel flows under pressure to the engine 10 via the fuel pump discharge 15 . In a typical vehicle engine the fuel flows through a fuel rail in the engine from which some of the fuel is consumed by the engine 10 . Fuel that is not consumed exits the engine 10 , and flows into a fuel return conduit 52 . From the fuel return conduit 52 , the return fuel splits between the return conduits 50 and 51 . [0018] The return fuel in return conduits 50 and 51 flows past the return restriction devices 100 and 101 which control the relative flow of return fuel into fuel tanks 30 and 31 , respectively. The return restriction devices 100 and 101 are controlled based on fuel levels 80 and 81 through the respective float arm mechanisms 60 and 61 and floats 70 and 71 . At a high fuel level in a tank, the return restriction devices 100 or 101 , which are respectively controlled through float arm mechanisms 60 and 61 , restrict the flow of return fuel into the corresponding fuel tanks 30 or 31 . The restriction of return fuel flow into tanks 30 and 31 decreases as the fuel level in the tank decreases. [0019] The restriction devices 90 , 91 , 100 , and 101 operate to balance fuel among tanks 30 and 31 by providing a varying degrees of restriction to fuel flow from and into tanks 30 and 31 based on the relative fuel levels 80 and 81 . For example, if the fuel level in tank 30 is greater than the fuel in tank 31 , then the draw restriction device 90 will be open to a greater degree than the draw restriction device 91 . This allows fuel to be preferentially drawn from tank 30 as opposed to tank 31 . Similarly, if the fuel level in tank 30 is greater than the fuel level in tank 31 , then the return restriction device 100 will close to a greater degree than the return restriction device 101 . Thus, fuel preferentially returns to tank 31 as opposed to tank 30 . With more fuel being drawn from and less fuel being returned to tank 30 relative to tank 31 , the fuel quantities in tanks 30 and 31 eventually become equal and the tanks are considered balanced. [0020] In an embodiment of the invention as shown in FIG. 2, the flow restriction devices are butterfly valve 150 , which is mounted inside draw conduit 40 , and butterfly valve 160 , which is mounted inside return conduit 50 . The butterfly valves 150 and 160 are supported on opposite ends of a shaft 110 . The shaft 110 is moveable mounted through both a draw conduit hole 120 in the draw conduit 40 and a return conduit hole 130 in the return conduit 50 . The butterfly valves 150 and 160 are supported perpendicular to each other when viewed form either end of the shaft 110 . The float arm mechanism 60 is attached to the support shaft 110 , and is designed to move the support shaft 110 through a 90-degree rotation from the full tank position to the empty tank position. [0021] In the operation of this embodiment, the draw butterfly valve 150 in the draw conduit 40 is fully open and the return butterfly valve 160 in the return conduit 50 is fully closed when the fuel level in the tank is high. Conversely, the draw butterfly valve 150 in the draw conduit 40 is fully closed and the return butterfly valve 160 in the return conduit 50 is fully open when the fuel level in the tank is low. [0022] The embodiment shown in FIG. 2 directly connects the float arm mechanism to the flow restriction devices. However, the float arm mechanism may also be indirectly connected to the float restriction devices through a gear mechanism, as shown in FIG. 5. In this variation a gear device 480 indirectly connects the float arm 60 to the restriction devices, draw gate 450 and return gate 460 . One skilled in the art would further recognize that restriction devices are not limited to butterfly valves but may be blades, balls, other types of valves or gates, etc. In addition, the restriction devices may be located inside the draw and return conduits or proximately close to the respective open ends of the conduits. [0023] Another embodiment of the present invention as shown in FIG. 3 includes a float 200 slideably mounted to a twisted guide 210 and the draw conduit 40 . A first end 260 and a second end 270 of the twisted guide 210 are rotatably mounted to a support structure 290 , which is mounted inside the tank (not shown). Alternatively, the first and second ends of the twisted guide 210 may be rotatably mounted to the draw conduit 40 , or an inside surface of the tank 30 . The draw restriction device is a draw gate 220 , which is mounted on the twisted guide 210 and is proximately close to the draw conduit inlet 230 . The return restriction device is a return gate 240 , which is mounted to the twisted guide 210 and is proximately close to the return conduit outlet 250 . [0024] For this embodiment the up and down movement of the float 200 in response to fuel level in the tank causes the twisted guide 210 to rotate around its longitudinal axis. The draw conduit 40 acts to prevent rotation of the float 200 , thus giving rise to rotation of the twisted guide 210 as the float 200 move up and down. The rotation of the twisted guide 210 results in the movement of draw gate 220 and return gate 240 . The draw gate 220 moves to restrict fuel flow into the draw conduit inlet 230 as the fuel level in the tank decreases. Conversely, the return gate 240 moves to restrict fuel flow out of the return conduit outlet 250 as the fuel level increases. Another embodiment of the present invention as shown in FIG. 4 includes a draw floatball 300 contained in a draw cage 310 , and a return floatball 320 contained in a return cage 330 . The draw cage 310 is attached to an end of a draw conduit extension 340 , which is U-shaped and is in close proximity to the bottom of the tank 30 . The second end of the draw conduit extension 340 is attached to the draw conduit 40 . A weep hole 350 in the draw conduit extension is optional. The return cage 330 is attached to the outlet of the return conduit 50 . [0025] In this embodiment, the return floatball 320 restricts fuel flow out of the return conduit 50 when the tank fuel level is high. When the level of fuel in the tank is low the draw floatball 300 restricts the flow of fuel out of the tank and into the draw conduit 40 . An optional weep hole 350 in the draw conduit extension 340 allows residual fuel in the very bottom of the fuel tank to be drawn into the draw conduit 40 . [0026] Another embodiment of this invention is a vehicle 500 with chassis 510 to which is mounted a circulating fuel system with at least two tanks. FIG. 6 specifically shows a truck with two tanks, 30 and 31 , mounted to a frame rail 520 of chassis 510 by a number of attachment devices 530 . Although not shown the rest of the circulating system, which includes an engine, a pump, a draw conduit, and a return conduit, are mounted to the vehicle chassis 510 or cab 505 . [0027] The embodiments disclosed above describe a variety of flow restriction devices which include butterfly valves, gates, and caged floatballs. Flow restriction devices may also include different types of valves such as ball valves, globe valves, check valves, flapper valves, etc. In addition, flow restriction devices may also include a venturi, an orifice, etc. including variations such as a variable venturi, a variable orifice, etc. One skilled in the art would understand that there are many types of flow restriction devices which may be used and the devices are not limited to those in the embodiments or examples given in this disclosure. [0028] In addition, a fuel level sending device may be provided for use in monitoring the fuel level in an individual tank. The fuel level sending device may be a mechanical device as the sight gauge 125 in FIG. 1 for the monitoring of the fuel level in close proximity to the tank, or an electric rheostat (not shown) connected to either a float or float arm for use in displaying the fuel level inside the cab of a vehicle. [0029] The present invention is also a method for detecting a fuel level in a tank and controlling both the draw of fuel out of and the return of fuel into a tank based on the detected fuel level. The method also includes the comparing of fuel levels in at least two tanks and determining a differential level which is used to control the fuel drawn and returned to each fuel tank. While the present invention is shown in several embodiments, it is not limited but susceptible to various changes and modifications without departing from the spirit and scope of the invention.	An apparatus and method for the balancing of fuel among tanks in a circulating fuel system. The tanks in the system have both a draw conduit and a return conduit mounted to and extending into the tank. Flow restriction devices are mounted in both the draw and the return conduits and are controlled by a fuel level detection system, which detects the fuel in the tank.	8
This is a divisional of U.S. Ser. No. 08/975,886, filed Nov. 21, 1997, now U.S. Pat. No. 5,808,103, which is a divisional of U.S. Ser. No. 08/682,497, filed Jul. 17, 1996, now U.S. Pat. No. 5,772,894. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to Rhodamine B which is modified to contain a vinyl group and its incorporation into radically polymerized compounds such as diallyldimenthyammonium chloride (DADMAC) polymers. 2. Description of the Prior Art Technological advances have made it economically practical to monitor the residual level of polymeric coagulants in wastewater effluents. Knowledge of the fate of coagulants has several advantages: 1) monitor treated water residuals, 2) control coagulant addition, and 3) elucidate coagulation mechanisms. This allows better control of dosage levels of these coagulants and to minimize these polymers contributing to pollution. A common approach to monitoring the level of water soluble polymer coagulants has been, to blend fluorescent dyes in small amounts and to use fluorescence of the mixture to determine the concentration of the polymer in aqueous systems. This approach has met with some success but it has limitations. In using simple blends of fluorescent dyes with polymeric coagulants there is the problem that the dye associates itself with other components, such as particulates. Subsequent fluorescent detection of the dye does not provide the location of the polymeric coagulant. A more recent approach has been to covalantly modify the dye so that it might be incorporated by means of chemical reaction into the polymer. Since the dye and the coagulant are physically attached, detection of the dye also detects the coagulant polymer. While this approach has met with some success, it is economically important that the dye be readily detected at low concentrations. Particularly there is not presently available a DADMAC polymer which contains chemically combined therewith a fluorescent dye suitable for monitoring these polymers when they are used in aqueous systems. If it were possible to modify polymers with a highly fluorescent dye, so that the dye became a part of the molecule and that the so modified polymer could be readily detected in the part per billion (ppb) range using existing fluorescent detection techniques, an advance in the art would be afforded. Also of importance would be, to use in the modification of the polymers, a dye which was easily synthesized from available chemicals, was stable and retained a high degree of fluorescence. Finally, the modified polymer should have activity as a water treating chemical corresponding to the activity of a similar unmodified polymer. SUMMARY OF THE INVENTION The invention comprises the Rhodamine B ester of a hydroxy C 2 -C 6 lower alkyl acrylate. The hydroxy lower alkyl radical preferably, is a linear hydroxy lower alkyl radical having the hydroxy group attached to the terminal carbon atom. In another preferred embodiment, the Rhodamine B ester is a hydroxy lower alkyl radical is a C 2 -C 4 radical, an example of which is the Rhodamine B ester of 4-hydroxybutyl acrylate. The important point is that the hydrocarbon linkage contain a hydroxy group and an acrylate group. The hydroxy group for modification of Rhodamine B, and the acrylate group for free radical polymeric incorporation. The invention also comprises copolymers of diallyldimetyl ammonium chloride which contains from 0.01-2 mole percent of the Rhodamine B esters of the types described above. It is noted that any free radical polymerization process could incorporate the invention as long as the dye's fluorescent properties were retained. The invention further contemplates using these polymers in water treating applications such as, but not limited to, coagulation. This allows the dosage and residual quantities of the polymers to be controlled and monitored using conventional fluorescence detecting equipment even though the polymers are present in the ppb range. THE DRAWINGS FIG. 1 shows a scheme for reacting Rhodamine B with 4-hydroxy butyl acrylate. FIG. 2 illustrates the polymerization of DADMAC with the modified Rhodamine B of FIG. 1. FIG. 3 demonstrates the ability of a DADMAC-Rhodamine B copolymer to act as a coagulant and be easily detectable at low dosages. DESCRIPTION OF THE PREFERRED EMBODIMENTS Modified Rhodamine B and its DADMAC Copolymers Rhodamine B is a well known fluorescent dye with its structure being shown in FIG. 1. 4-hydroxy butyl acrylate is a well known acrylate ester and is commercially available. While this ester is preferred other acrylate esters that may be used in the practice of the invention are 2-hydroxy ethyl acrylate and 6-hydroxy hexyl acrylate and the like. The hydroxy acrylate esters are desirably reacted with the carboxylic acid group of the Rhodamine B at low temperatures such at about room temperature ±24 degrees C. using the synthetic methods generally described in the publications: Tetrahedron Letters No. 46 pp 4775-8, Pergamon Press, 1978 and Euro Polymer J. Vol. 27 No. 10 pp 1045 and 1048. The disclosures of these references are incorporated herein by reference. The DADMAC polymers modified by the acrylate ester modified Rhodamine B may be synthesized using known free radical polymerization techniques. These copolymers may contain between 0.01 to 2 mole percent of the modified Rhodamine B monomer based on DADMAC. Of course, the invention is in and or itself, a monomer and potentially could be incorporated at higher levels. Preferably the amount of the fluorescent monomer is within the range of 0.1 to 1 mole percent. The modified or tagged DADMAC polymers have an intrinsic viscosity, as measured in 1M NaNo 3 at 30 degrees C., of at least 0.3. For most water treating applications such as coagulation the intrinsic viscosity should be within the range of 0.3 to 0.9. For some applications the intrinsic viscosity may be 1.6 or greater. When used to treat industrial waters the dosage of the modified polymers would usually vary from a few parts per million up to several hundred depending on the system treated and the intrinsic viscosity of the polymer used. When used as a coagulant the dosage would typically be between a few ppm up to ca. 100 ppm. EVALUATION OF THE INVENTION Synthetic Procedure: 4-Hydroxybutylacrylate/Rhodamine B Ester The following procedure was used to prepare this material in the laboratory and is shown in FIG. 1. To a 100 mL round bottom flask, equipped with a magnetic stirring bar, was added 3.00 g (6.26 mole) of Rhodamine B (97%) and 40 mL of anhydrous methylene chloride solvent. The mixture was stirred, under nitrogen, until the Rhodamine reagent was dissolved. An amount (0.08 g, 0.65 mole) of 4-dimethylaminopyridine (DMAP) was then added to the flask, along with 1.5 mL (1.6 equivalents) of 4-hydroxybutylacrylate (HBA, 96%). The mixture was then cooled to 0 degrees C., and 6.26 mL of 1,3-dicyclohexylcarbodiimide (DCC, 1.0 M solution in methylene chloride, 1 equivalent) was injected into the reaction flask with stirring. The reaction was held at 0 degrees C. for 1/2 hour, then the reaction was allowed to slowly warm to room temperature, and then stirred under nitrogen overnight. It was noted that the reaction by-product dicyclohexylurea (DCU) began to precipitate from solution shortly (approximately 3 minutes) after the addition of the DCC. At the end of the reaction period the methylene chloride solvent was removed via rotary evaporation, and the reaction mixture re-dissolved in 50 mL of acetonitrile. The insoluble DCU was filtered off and the solvent removed and the product dried under a vacuum, leaving an amorphous solid, that is soluble in water and most polar organic solvents. The product also has the characteristic of an extremely powerful dye. Some impurities were removed by passing the material through a silica gel plug (70-270 mesh) using an acetonitrile mobile phase. In this way 1.6 g of the dye was isolated (molecular wt.=605.19 amu). Thin layer chromatography (TLC) showed the presence of three spots, two are weak and one is strong. The strong spot corresponds to the product. A weak spot below the product spot corresponds to unreacted Rhodamine B. A weak spot above the product spot is unknown, it may be due to dimerized product. All the spots seemed to be fluorescent. The TLC solvent that gave the best separation was isopropyl alcohol. NMR analysis gave rise to complex spectra that indicated that the ester product was formed. The purity was approximately 90%. The major impurities were approximately 5% unreacted Rhodamine B reagent and 5% of an unknown compound. Synthetic Procedure: Tagged DADMAC Polymer The following laboratory method was used to prepare a DADMAC polymer containing the above Rhodamine acrylate dye monomer and is shown in FIG. 2. Into a 250 mL reaction kettle equipped with a stirring shaft, thermocouple, condenser, nitrogen inlet, and an addition port, was added 0.28 g (0.13 mole percent based on monomer) of the dye monomer (approximately 90% pure) and 5.16 g D.I. water. To this was added 80.64 g of a 62.0% DADMAC monomer solution. The mixture was stirred and purged with nitrogen. A quantity of 18.0 g of NaCl was added to the mixture and the reaction mixture heated to 58 degrees C. in a water bath. An initiator solution was prepared by dissolving 0.50 g of V-50 initiator into 5.00 g of D.I. water. One mL of this initiator solution was then injected into the reactor, and a timer was started. After one hour another 1 mL portion of the initiator solution was added to the reactor, and again at the two hour and three hour mark. At this point the mixture was a very thick paste. After 4.5 hours the polymer began to climb up the stirring shaft. When the timer reached 5 hours, 40 mL of D.I. water was added to the mixture, then an additional 17 mL of water was added at 5.25 hours. The reaction temperature was then raised to 80 degrees C., and the remaining 1 mL of the initiator solution was injected into the reactor. The mixture was then held at 80 degrees C. with stirring for one hour. The reactor was removed from the water bath and 83 g of D.I. water was added with stirring. The mixture was allowed to cool and another 83 g of water was added to the reactor to give a 15% polymer solution. The product produced was a viscous dark pink material. The following procedures were used to characterize the polymer. The Brookfield viscosity was obtained using a #2 spindle at a speed of 12. The intrinsic viscosity (I.V.) was taken on a 1% polymer solution prepared from 6.67 g of polymer product, 50 mL of 2M NaNO3, 1 mL of 1M sodium acetate solution, and diluted to 100 mL with D.I. water. Dialysis experiments were performed using a 12,000-14,000 MW cut-off membrane. Standard techniques were employed. The polymer product was precipitated and isolated by adding a small amount of the product to a large volume of acetone. The resulting gel was isolated and dissolved in a small amount of methanol. Any insoluble solids were filtered off, and the methanol polymer solution added to a large volume of acetone. The precipitated polymer was collected, washed, and dried under a vacuum. The dye monomer was incorporated into the dye at 0.13 mole percent (based on DADMAC monomer, assuming a dye monomer purity of 90%), or 0.08% by weight of product. About 99% incorporation of the dye into the polymer was achieved. Total polymer solids of the tagged polyDADMAC was measured at 15%. The synthesized tagged polymer had the following characteristics setforth in Table I. TABLE I______________________________________ Tagged pDADMAC pDADMAC______________________________________Appearance: Deep Red/Pink Color Clear White Brookfield Viscosity: 1363 cps 990 cps I.V.: 1.0 dL/g 1.03 dL/g pH: 4.85 4.68 Wt. Average MW: 890,000 475,000 Number Average MW: 70,000 32,000 Polydispersity: 12.7 14.8 Polymer Solids: 15% (theo.) 14.97______________________________________ Except for the color, tagged pDADMAC has similar characteristics to un-tagged pDADMAC. PolyDADMAC dye incorporation was determined analytically. The polymer remained colored after precipitation and washing. The polymer was also placed in a 12,000-14,000 dialysis membrane and dialyzed with D.I. water for 48 hours. Only a small amount of color was observer to pass out of the membrane. The material in the membrane was bright pink. A control experiment was done, in which, the dye monomer was blended with a sample of un-tagged pDADMAC. In this case practically all of the dye seemed to pass through the membrane leaving the un-tagged polymer behind. Analysis indicated that there were about 9 ppm of residual tagged monomer in the tagged polymer. Detection Limits Lower detection limits are desirable for several reasons. Lower detection limits allows formulators to use lower dye levels in new products. For control purposes, a dye-tagged molecule requires detection without changing product properties. Finally, for tagged polymer detection, the higher the dye molecule fluorescence sensitivity, the lower the detection limit. This last point is important for answering the question of polymer residuals in treated waters. Fluorescence sensitivity is defined as: Fluorescence Sensitivity=extinction coefficient×Quantum Yield From Table II it is shown the modified Rhodamine has a higher Fluorescence Sensitivity than Rhodamine B. By modifying Rhodamine B we get two distinct advantages over Rhodamine B: high fluorencence sensitivity and the ability to incorporate the dye into free-radical polymerization reactions. For tagged pDADMAC, the detection limit was determined to be 50 ppb using standard fluorometry techniques. It could be as low as 10 ppb. TABLE II______________________________________ Extinction Absorption Coefficient Relative Quantum Peak (nm) (1-mol/cm) Yield______________________________________Rhodamine B 555 110,000 0.62 (absolute) Modified 560 88,500 0.96 Rhodamine B Tagged 585 181 0.425 polyDADMAC______________________________________ Rhodamine B has an absolute Quantum yield of 0.62. Stability Since the Rhodamine B modified polymers is formed by free radical polymerization via chemical reaction of an acrylate onto the carboxphenyl moiety, the reverse hydrolysis reaction would remove the dye moiety. Consequently, the acrylate group's stability to hydrolysis is important. The modified Rhodamine B-acrylate monomer was subjected to potential hydrolysis conditions and using chromatography to determine the free Rhodamine B (residual and from hydrolysis), the monomer, and any other hydrolysis products. Results showed that at pH 7 and low monomer concentration (1-20 ppm), about 15-20% of the tagged monomer were hydrolyzed after 28 days at room temperature without exposure to light. However, high monomer concentration (800 ppm) solution appeared to be stable up to 4 weeks at room temperature without exposure to light. It is predicted that the dye monomer's hydrolysis rate will be slower when it is attached to a polymer, due to possible steric constraints. Tagged Polymer Activity Aeration Basin effluent wastewater from a refinery was used for activity testing. FIG. 3 shows that tagged polyDADMAC has activity. This result proves that chemically tagging pDADMAC does not inhibit coagulation power. Activity was measured in NTUs (Nephrolytic Turbidity Units).	Disclosed are the Rhodamine B esters of hydroxy C 2 -C 6 lower alkyl acrylates. Specifically, the hydroxy lower alkyl radical is a linear hydroxy lower alkyl radical having the hydroxy group attached to the terminal carbon atom. Also shown are copolymers of diallyldimetyl ammonium chloride which contains from 0.01-2 mole percent of these Rhodamine B esters and their use in treating industrial waters.	2
CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation application of U.S. patent application Ser. No. 12/709,220 filed Feb. 19, 2010, now U.S. Pat. No. 8,968,338, which is a divisional application of U.S. patent application Ser. No. 11/813,695, filed Jul. 11, 2007, now U.S. Pat. No. 8,465,500, which is a 371 of PCT/US06/01699 filed Jan. 19, 2006, which claims the benefit of U.S. Provisional Patent Application No. 60/645,677 filed Jan. 21, 2005. BACKGROUND OF THE INVENTION Various types of surgical procedures are currently performed to investigate, diagnose, and treat diseases of the heart and the great vessels of the thorax. Such procedures include repair and replacement of mitral, aortic, and other heart valves, repair of atrial and ventricular septal defects, pulmonary thrombectomy, treatment of aneurysms, electrophysiological mapping and ablation of the myocardium, and other procedures in which interventional devices are introduced into the interior of the heart or a great vessel. Using current techniques, many of these procedures require a gross thoracotomy, usually in the form of a median sternotomy, to gain access into the patient's thoracic cavity. A saw or other cutting instrument is used to cut the sternum longitudinally, allowing two opposing halves of the anterior or ventral portion of the rib cage to be spread apart. A large opening into the thoracic cavity is thus created, through which the surgical team may directly visualize and operate upon the heart and other thoracic contents. Surgical intervention within the heart generally requires isolation of the heart and coronary blood vessels from the remainder of the arterial system, and arrest of cardiac function. Usually, the heart is isolated from the arterial system by introducing an external aortic cross-clamp through a sternotomy and applying it to the aorta between the brachiocephalic artery and the coronary ostia. Cardioplegic fluid is then injected into the coronary arteries, either directly into the coronary ostia or through a puncture in the aortic root, so as to arrest cardiac function. In some cases, cardioplegic fluid is injected into the coronary sinus for retrograde perfusion of the myocardium. The patient is placed on cardiopulmonary bypass to maintain peripheral circulation of oxygenated blood. Of particular interest to the present invention are intracardiac procedures for surgical treatment of heart valves, especially the mitral and aortic valves. According to recent estimates, more than 79,000 patients are diagnosed with aortic and mitral valve disease in U.S. hospitals each year. More than 49,000 mitral valve or aortic valve replacement procedures are performed annually in the U.S., along with a significant number of heart valve repair procedures. Various surgical techniques may be used to repair a diseased or damaged valve, including annuloplasty (contracting the valve annulus), quadrangular resection (narrowing the valve leaflets), commissurotomy (cutting the valve commissures to separate the valve leaflets), shortening mitral or tricuspid valve chordae tendonae, reattachment of severed mitral or tricuspid valve chordae tendonae or papillary muscle tissue, and decalcification of valve and annulus tissue. Alternatively, the valve may be replaced, by excising the valve leaflets of the natural valve, and securing a replacement valve in the valve position, usually by suturing the replacement valve to the natural valve annulus. Various types of replacement valves are in current use, including mechanical and biological prostheses, homografts, and allografts, as described in Bodnar and Frater, Replacement Cardiac Valves 1-357 (1991), which is incorporated herein by reference. A comprehensive discussion of heart valve diseases and the surgical treatment thereof is found in Kirklin and Barratt-Boyes, Cardiac Surgery 323-459 (1986), the complete disclosure of which is incorporated herein by reference. The mitral valve, located between the left atrium and left ventricle of the heart, is most easily reached through the wall of the left atrium, which normally resides on the posterior side of the heart, opposite the side of the heart that is exposed by a median sternotomy. Therefore, to access the mitral valve via a sternotomy, the heart is rotated to bring the left atrium into a position accessible through the sternotomy. An opening, or atriotomy, is then made in the left atrium, anterior to the right pulmonary veins. The atriotomy is retracted by means of sutures or a retraction device, exposing the mitral valve directly posterior to the atriotomy. One of the fore mentioned techniques may then be used to repair or replace the valve. An alternative technique for mitral valve access may be used when a median sternotomy and/or rotational manipulation of the heart are undesirable. In this technique, a large incision is made in the right lateral side of the chest, usually in the region of the fifth intercostal space. One or more ribs may be removed from the patient, and other ribs near the incision are retracted outward to create a large opening into the thoracic cavity. The left atrium is then exposed on the posterior side of the heart, and an atriotomy is formed in the wall of the left atrium, through which the mitral valve may be accessed for repair or replacement. Using such open-chest techniques, the large opening provided by a median sternotomy or right thoracotomy enables the surgeon to see the mitral valve directly through the left atriotomy, and to position his or her hands within the thoracic cavity in close proximity to the exterior of the heart for manipulation of surgical instruments, removal of excised tissue, and/or introduction of a replacement valve through the atriotomy for attachment within the heart. However, these invasive, open-chest procedures produce a high degree of trauma, a significant risk of complications, an extended hospital stay, and a painful recovery period for the patient. Moreover, while heart valve surgery produces beneficial results for many patients, numerous others who might benefit from such surgery are unable or unwilling to undergo the trauma and risks of current techniques. The mitral and tricuspid valves inside the human heart include an orifice (annulus), two (for the mitral) or three (for the tricuspid) leaflets and a subvalvular apparatus. The subvalvular apparatus includes multiple chordae tendinae, which connect the mobile valve leaflets to muscular structures (papillary muscles) inside the ventricles. Rupture or elongation of the chordae tendinae result in partial or generalized leaflet prolapse, which causes mitral (or tricuspid) valve regurgitation. A commonly used technique to surgically correct mitral valve regurgitation is the implantation of artificial chordae (usually 4-0 or 5-0 Gore-Tex sutures) between the prolapsing segment of the valve and the papillary muscle. This operation is generally carried out through a median sternotomy and requires cardiopulmonary bypass with aortic cross-clamp and cardioplegic arrest of the heart. SUMMARY OF THE INVENTION The present invention is a method and apparatus for performing a minimally invasive thoracoscopic repair of heart valves while the heart is beating. More specifically the method includes inserting an instrument through the subject's chest wall and through the heart wall. The instrument carries on its distal end a movable element which is manipulated to grasp a valve leaflet and hold it while a needle mechanism punctures the valve leaflet and loops a suture around a portion of the valve leaflet. The instrument is withdrawn from the heart along with the suture and the suture is tied off at the apex of the heart after adjusting its tension for optimal valve operation as observed with an ultrasonic imaging system. In addition to grasping and needle mechanisms, the instrument includes fiber optics which provide direct visual indication that the valve leaflet is properly grasped. A set of illuminating fibers terminate at the distal end of the instrument around the needle mechanism in close proximity to a set of sensor fibers. The sensor fibers convey light from the distal end of the instrument to produce an image for the operator. When a valve leaflet is properly grasped, light from the illuminating fibers is reflected off the leaflet surface back through the sensor fibers. On the other hand, if the valve leaflet is not properly grasped the sensor fibers see blood. A general object of the invention is to provide an instrument and procedure which enables heart valves to be repaired without the need for open heart surgery. The instrument is inserted through an opening in the chest wall and into a heart chamber while the heart is beating. The instrument enables repair of a heart valve, after which it is withdrawn from the heart and the chest. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cut-out view of a patient's chest showing an instrument embodying the invention being inserted into a patient's chest cavity through a thorascopic port that is inserted into the patient's chest. FIG. 2 is a cut-out view of a patient's chest showing an instrument embodying the invention grasping a prolapsing segment of the mitral valve inside the patient's chest cavity and securing an artificial chorda to the free edge of the prolapsing segment of the mitral valve. FIG. 3 is a cut-out view of a patient's chest cavity showing an instrument embodying the invention tensioning the neo-implanted chorda. FIG. 4 is an isometric view of an instrument embodying the invention. FIG. 5 is a detailed isometric view of the distal end of an instrument embodying the invention. FIG. 6A is a detailed side elevation view of the distal end of an instrument embodying the invention showing the tip in a closed position. FIG. 6B is a detailed side elevation view of the distal end of an instrument embodying the invention showing rods inside the instrument that are capable of sliding to move the tip to an open position. FIG. 7 is a detailed isometric view of the distal end of an instrument embodying the invention showing the needle lumen and four fiberoptic channels that are disposed around the needle lumen. FIG. 8A is a detailed isometric view of the preferred embodiment of the suture deployment system showing the positioning of a heart valve leaflet with respect to the instrument. FIG. 8B is a detailed isometric view of the preferred embodiment of the suture deployment system showing the tip of the distal end of the instrument closing on the leaflet to grasp the leaflet such that the needle can puncture and push the suture through the leaflet. FIG. 8C is a detailed isometric view of the preferred embodiment of the suture deployment system showing the needle retracting back through the leaflet to pull the suture loop back through the puncture opening in the leaflet. FIG. 8D is a detailed isometric view of the preferred embodiment of the suture deployment system showing the distal end of the instrument releasing the leaflet and pulling both ends and the midpoint of the suture as the instrument withdraws from the patient's heart. FIG. 8E is a detailed side elevation view of the preferred embodiment of the suture deployment where the suture is released from the instrument and the two suture ends are inserted through the loop. FIG. 8F is a detailed side elevation view of the preferred embodiment of the suture deployment system wherein the ends of the suture are pulled and the loop of the suture slides back along the suture to form a Larks head around the edge of the valve leaflet. FIG. 9A is a detailed isometric view of a second embodiment of the suture deployment system showing the tip of the distal end of the instrument grasping the heart valve leaflet and showing a suture that is a closed loop with one end of the loop disposed in the tip of the instrument and the other end disposed in the lumen and wrapped around the needle. FIG. 9B is a detailed isometric view of a second embodiment of the suture deployment system showing the needle puncturing the leaflet and pushing the suture through the leaflet. FIG. 9C is a detailed isometric view of a second embodiment of the suture deployment system showing the needle retracting back through the leaflet to pull the looped suture back through the opening in the leaflet and showing the instrument releasing the leaflet. FIG. 9D is a detailed isometric view of a second embodiment of the suture deployment system showing the instrument withdrawing to slide the unhooked end of the suture along the length of the needle towards the leaflet to form a Larks head around the leaflet's edge. FIG. 10A is a detailed isometric view of a third embodiment of the suture deployment system showing the tip of the distal end of the instrument grasping the heart valve leaflet and showing the midpoint of the suture being looped around the lumen and the two loose ends of the suture being coiled up in the tip of the distal end of the instrument. FIG. 10B is a detailed isometric view of a third embodiment of the suture deployment system showing the needle puncture and push the suture through the leaflet and through the loop of the free ends of the suture wherein the needle then hooks the free ends of the suture. FIG. 10C is a detailed isometric view of a third embodiment of the suture deployment system showing the needle retracting back through the leaflet and showing the instrument releasing the leaflet. FIG. 10D is a detailed isometric view of a third embodiment of the suture deployment system showing the instrument withdrawing from the heart to pull the free ends of the suture back through the valve leaflet and forming a Larks head around the leaflet's edge by the midpoint of the suture. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Under general anesthesia and double-lumen ventilation, the patient is prepped and draped so as to allow ample surgical access to the right lateral, anterior and left lateral chest wall (from the posterior axillary line on one side to the posterior axillary line on the other side). As shown in FIG. 1 , one or more thoracoscopic ports are inserted in the left chest through the intercostal spaces and an instrument 10 is inserted through one of these ports into the chest cavity. Alternatively, a small (3-5 cm) left thoracotomy is performed in the fifth or sixth intercostals space on the anterior axillary line. The patient is fully heparinized. After collapsing the left lung, the pericardium overlying the apex 12 of the left ventricle 14 is opened and its edges are suspended to the skin incision line. This provides close access to the apex of the heart. Guidance of the intracardiac procedure is provided by a combination of transesophageal or intravascular echocardiography (not shown in the drawings) and with direct visualization through a fiber-optical system built into the instrument 10 as will be described in detail below. A double-pledgeted purse-string suture is placed on the apex of the left ventricle 12 and a stab incision is made at that location. The surgical instrument 10 is inserted through this incision, into the left ventricular chamber 14 of the beating heart. Referring particularly to FIG. 2 , the instrument 10 may be used to grasp a prolapsing segment of the mitral valve 16 and an artificial chorda 18 may be secured to its free edge. Accurate positioning of the implanted artificial chorda 18 is guaranteed by both echo and direct fiberoptic visualization as will be described in detail below. The instrument 10 is then withdrawn from the left ventricle chamber 14 pulling the unattached end of the neo-implanted chorda 18 with it. Hemostasis is achieved by tying the purse-string suture around the incision in the left ventricular apex 12 after the instrument 10 and chorda 18 are withdrawn. As shown in FIG. 3 , the neo-implanted chorda 18 is appropriately tensioned under direct echo-Doppler visualization and secured outside the apex 12 of the heart. That is, a tension is placed on the neo-implanted chorda 18 and the operation of the repaired valve 16 is observed on the ultrasound image. The tension is adjusted until regurgitation is minimized. While a single chorda 18 is implanted in the above description, additional chorda, or sutures, can be implanted and attached to the apex 12 of the heart wall with optimal tension. In this case the tensions in all the neo-implanted chorda 18 are adjusted until optimal valve operation is achieved. As shown in FIGS. 4 and 5 , the instrument 10 used to perform the above procedure includes a rigid metal shaft 100 having a handle 120 at its extrathoracic (proximal) end which enables the instrument to be manipulated and guided into position. Actuating mechanisms for controlling the grasping mechanism and needle mechanism located at the distal end 140 of the instrument are also mounted near the handle 120 . As will be described below, the grasping mechanism is operated by squeezing the scissor-grip handle 120 , and the needle mechanism is operated by moving an up-turned control shaft 122 . Located on the distal, intracardiac end 140 of the instrument 10 is a grasping mechanism which can be operated to hold a prolapsing valve leaflet. As shown in FIGS. 6 and 7 , in the preferred embodiment this mechanism is a tip 160 which is supported on the distal end of the shaft 100 by a set of rods 162 . The rods 162 slide within the shaft 100 to move the tip 160 between an open position as shown in FIGS. 6B and 7 and a closed position as shown in FIG. 6A when the scissor-grip handle 120 is operated. As will be explained below, a mitral valve leaflet is located in the gap between the open tip 160 and the distal end of shaft 100 and it is captured by closing the tip 160 to pinch the valve leaflet therebetween. Disposed in a needle lumen 164 formed in the shaft 100 is a needle 180 which connects to the control shaft 122 at the proximal end of shaft 100 . Needle mechanism 180 slides between a retracted position in which it is housed in the lumen 164 near the distal end of the shaft 100 and an extended position in which it extends into the sliding tip 160 when the tip is in its closed position. As a result, if a valve leaflet has been captured between the tip 160 and the distal end of shaft 100 the needle may be extended from the lumen 164 by moving control shaft 122 to puncture the captured leaflet and pass completely through it. The distal end of the shaft 100 also contains an artificial chorda, or suture 18 that is to be deployed in the patient's heart. The suture 18 is typically a 4-0 or 5-0 suture manufactured by a company such as Gore-Tex. This suture 18 is deployed by the operation of the grasping mechanism and the needle mechanism 180 as described in more detail below. The shaft 100 has a size and shape suitable to be inserted into the patient's chest and through the left ventricle cardiac wall and form a water-tight seal with the heart muscle. It has a circular or ellipsoidal cross-section and it houses the control links between the handle end and the intracardiac end of the instrument as well as a fiber optic visualization system described in more detail below. As shown in FIGS. 8A-8F , the preferred embodiment of the suture deployment system at the distal end of the instrument 10 is positioned around a valve leaflet 16 to be repaired as shown in FIG. 8A . The suture 18 is folded at the middle to form a loop 19 that is positioned in the tip 160 . Both ends of the suture 18 are disposed in a suture lumen 165 formed in the shaft 100 beneath the rods 162 . As shown in FIG. 8B , the valve leaflet 16 is grasped by closing the tip 160 , and the needle 180 is extended to puncture the leaflet 16 and extend into the tip 160 . A notch 166 formed on one side of the needle 180 hooks the suture loop 19 . The needle 180 is then retracted back through the leaflet 16 to pull the suture loop 19 through the puncture opening as shown in FIG. 8C . The leaflet 16 is then released and the instrument 10 is withdrawn from the heart as shown in FIG. 8D pulling both ends and the midpoint of the suture 18 with it. As shown in FIG. 8E , the suture 18 is released by the instrument 10 and the surgeon inserts the two suture ends 21 through the loop 19 at its midpoint. The ends 21 are then pulled and the loop 19 slides along the suture 18 back into the heart chamber 14 where it forms a Larks head around the edge of the valve leaflet as shown in FIG. 8F . Multiple sutures 18 may be implanted in this manner until a satisfactory result is obtained. After deployment of the sutures 18 , the heart wall incision is repaired by either a pre-positioned purse-string suture or by any kind of appropriate hemostatic device or technique. Hemostasis is checked, appropriate chest drainage tubes are positioned and secured, and all incisions are closed. As shown in FIGS. 9A-9D , a second embodiment of the suture deployment system at the distal end of the instrument 10 is positioned around a valve leaflet 16 to be repaired as shown in FIG. 9A . The suture 18 in this embodiment is a closed loop with one end of the loop disposed in the tip 160 and its other end disposed in the lumen 164 and wrapped around the needle 180 . The needle 180 is extended through the grasped valve leaflet 16 into the instrument tip 160 where it hooks one end of the looped suture 18 in a notch 166 formed on one side of the needle as shown in FIG. 9B . The needle 180 is then retracted to pull the looped suture 18 through the puncture opening in the leaflet 16 . The leaflet is then released as shown in FIG. 9C by sliding the tip 160 to its open position. The instrument 10 is then withdrawn as shown in FIG. 9D to slide the unhooked end of the looped suture 18 along the length of the needle toward the leaflet 16 where it forms a Larks head around the leaflet edge. The instrument 10 is then withdrawing from the heart chamber 14 pulling the hooked end of the suture 18 through the heart wall. The suture 18 is secured to the outside of the heart apex. As shown in FIGS. 10A-10D , a third embodiment of the suture deployment system at the distal end of the instrument 10 is positioned around a valve leaflet 16 to be repaired as shown in FIG. 10A . The midpoint 17 of the suture 18 is looped around the lumen 164 and its two loose ends 20 are coiled up in the tip 160 . After the tip 160 is closed to capture the valve leaflet 16 , the needle 180 is extended through the grasped valve leaflet 16 into the instrument tip 160 . The free ends 20 of the suture 18 are positioned in the tip 160 to form a loop 19 and a notch 166 formed on one side of the needle extends through this loop 19 and “hooks” the free ends of the suture 18 as shown in FIG. 10B . The needle 180 is then retracted back into the lumen 164 to pull the hooked ends of the suture 18 through the puncture opening in the leaflet 16 . The leaflet is then released as shown in FIG. 10C by sliding the tip 160 to its open position. The instrument 10 is then withdrawn from the heart as shown in FIG. 10D to pull the free ends 20 back through the valve leaflet 16 and a Larks head is formed around the leaflet edge by the midpoint 17 of the suture 18 . The instrument 10 is then withdrawn from the heart chamber 14 pulling the free ends 20 of the suture 18 through the heart wall. The free ends 20 of the suture 18 are secured to the outside of the heart apex. Other suture deployment systems are possible where, for example, the needle may penetrate through the leaflet and link up with a snap fitting device that is attached to one end of the looped suture 18 in the instrument tip 160 . The needle then withdraws pulling the device and looped suture back through the penetration opening in the leaflet as described above. As shown in FIG. 7 to enhance visibility during this procedure, four fiberoptic channels 170 extend along the length of the instrument shaft 100 and terminate at its distal end. Each channel 170 contains at least one illuminating fiber which connects at its extrathoracic end to a white light source (not shown in the drawings). Each channel 170 also contains at least one sensor fiber which conveys reflected light from the distal end back to a visualization monitor (not shown in the drawings) connected to its extrathoracic end. In the preferred embodiment each channel 170 includes two illuminating fibers and two sensor fibers. The four fiberoptic channels 170 are disposed around the needle lumen 164 such that when a valve leaflet 16 is properly grasped, the valve leaflet tissue 16 rests against the distal end of all the fibers 170 . As a result, light is reflected off the tissue back into the sensor fibers and four white circles are displayed on the visualization monitor. When the leaflet 16 is not properly pressed against the distal end of a channel 170 , light is not reflected from the leaflet 16 and the visualization monitor displays the red color reflected from blood. When no valve tissue is captured, the monitor shows four red dots and when valve tissue is captured, the dots corresponding to the fiberoptic channels 170 contacting the tissue turn white. If the monitor shows all four dots as white, it means that the valve tissue capture is optimal. If only the upper two dots turn white and the bottom dots remain red, the “bite” on the valve leaflet 16 is too shallow for a proper attachment of the suture 18 . In addition to the fiberoptic visualization system that insures that a valve leaflet is properly captured, other real-time visualization systems are employed to help guide the instrument 10 to the valve leaflet 16 . Preferably a transesophageal or intravascular color-Doppler echocardiography system is used for this purpose. As explained above, this imaging system is also used to determine the length of the neo-implanted artificial chordae in real-time by observing reduction or disappearance of regurgitation by transesophageal or intravascular color-Doppler echocardiography.	An instrument for performing thorascopic repair of heart valves includes a shaft for extending through the chest cavity and into a heart chamber providing access to a valve needing repair. A movable tip on the shaft is operable to capture a valve leaflet and a needle is operable to penetrate a capture valve leaflet and draw the suture therethrough. The suture is thus fastened to the valve leaflet and the instrument is withdrawn from the heart chamber transporting the suture outside the heart chamber. The suture is anchored to the heart wall with proper tension as determined by observing valve operation with an ultrasonic imaging system.	0
BACKGROUND OF THE INVENTION [0001] This invention relates generally to imaging systems using pixilated detectors, and more particularly to pixilated semiconductor detectors in imaging systems. [0002] Imaging devices, such as gamma cameras and computed tomography (CT) imaging systems, are used in the medical field to detect radioactive emission events emanating from a subject, such as a patient and to detect transmission x-rays attenuated by the subject, respectively. An output, typically in the form of an image that graphically illustrates the distribution of the sources of the emissions within the object and/or the distribution of attenuation of the object is formed from these detections. An imaging device may have one or more detectors that detect the number of emissions, for example, gamma rays in the range of 140 keV, and may have one or more detectors to detect x-rays that have passed through the object. Each of the detected emissions and x-rays is typically referred to as a “count,” but may also be counted together as a ‘signal current’ and the detector determines the number of counts received at different spatial positions. The imager then uses the count tallies to determine the distribution of the gamma sources and x-ray attenuator, typically in the form of a graphical image having different colors or shadings that represent the processed count tallies. [0003] A pixilated semiconductor detector, for example, a detector fabricated from cadmium zinc telluride (CZT), may provide an economical method of detecting the gamma rays and x-rays. However, a low energy tail on the energy spectrum resulting from the CZT interaction with the radiation may interfere with the ability to distinguish direct gamma rays and x-rays from scattered gamma rays and x-rays. The tail may result from a different response of the semiconductor material in the regions between the pixels compared to the response from within the pixels. [0004] Another problem that may be associated with using a pixilated semiconductor detector is a loss of potential detector spatial resolution due to a gap between a detector collimator and the active detector surface. The gap is a result of known mounting technology that makes collimator exchange easier. The divergence of the gamma and x-ray photons in the gap may contribute to a degradation of a spatial resolution realizable from the detector. At least some known imaging devices use a variety of interchangeable collimators for respective different applications. Each collimator may differ in length and bore of the holes, and the weight of the collimators necessitates special handling equipment and procedures. This further increases the likelihood of a degradation of spatial resolution of the detector. [0005] Furthermore, due to the fine tolerances needed to achieve accurate resolution of detector images, producing collimators having holes that are substantially aligned with each detector pixel is difficult, thus affecting image resolution. BRIEF DESCRIPTION OF THE INVENTION [0006] In one embodiment, a method of detecting ionizing radiation is provided. The method includes pixelating a semiconductor substrate such that each pixel comprises a central region and a region of variable response, substantially blocking the ionizing radiation from reaching the region of variable response, and receiving the ionizing radiation with the central region. [0007] In another embodiment, an imaging system that includes a semiconductor detector is provided. The imaging system includes a pixilated semiconductor substrate that is responsive to ionizing radiation, the substrate including a first surface in a direction of a source of ionizing radiation, and a collimating mask covering the substrate surface, the collimating mask including a plurality of mask openings exposing a central region of a pixel of the semiconductor detector substrate to the ionizing radiation, the collimating mask including mask septa that facilitate substantially blocking the incident ionizing radiation from a region of variable response associated with the pixel. [0008] In yet another embodiment, a collimating mask for a pixilated radiation detector is provided. The collimating mask includes a mask portion formed generally in a grid arrangement wherein the grid is configured to expose a central region of a pixel defined in a detector substrate of the detector, and to overlay a region surrounding the central region. [0009] In still another embodiment, a detector assembly for an imaging system is provided. The detector assembly includes a radiation detector having a pixilated semiconductor substrate that includes a pixel electrode coupled to a first surface of the substrate wherein the pixel electrode defines a pixel region of the substrate, a cathode covering a second surface of the substrate, a dielectric layer covering the cathode, a collimating mask that includes a mask portion that has openings therethrough surrounded by a mask septa wherein the mask portion is configured to expose a central region of the pixel, and to overlay a region surrounding the central region. The detector assembly also includes a collimator removably couplable to the radiation detector wherein the collimator has apertures therethrough, and the apertures are configured to substantially align with the collimating mask openings. The collimator is further configured to receive another collimator such that apertures of each collimator substantially align with respect to each other. BRIEF DESCRIPTION OF THE DRAWINGS [0010] FIG. 1 is a graph that illustrates an exemplary energy spectrum of a single pixel of a pixilated CZT detector exposed to substantially unscattered 140 keV gamma rays; [0011] FIG. 2 is a cross-sectional elevation view of an exemplary imaging device detector having a plurality of pixilated semiconductor detector elements according to an embodiment of the present invention; [0012] FIG. 3 is a perspective view of the imaging device detector shown in FIG. 2 ; [0013] FIG. 4 is a schematic side elevation view of a portion of the imaging device detector shown in FIG. 2 ; and [0014] FIG. 5 is a schematic illustration of an exemplary array of imaging device detectors configured to couple to an arcuate base according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION [0015] FIG. 1 is a graph 50 that illustrates an exemplary energy spectrum of a single pixel of a pixilated CZT detector exposed to substantially unscattered 140 keV gamma rays. Graph 50 includes an x-axis graduated in units of keV and a y-axis representative of an amount of total counts or count rate observed at each keV level. An energy spectrum peak 52 centered about 140 keV represents the gamma rays that have been absorbed substantially within a central region portion of the single pixel. The distribution of signal amplitudes of these events is approximately Gaussian. However, a significant number of gamma rays are also detected in the portion of the energy response spectrum that tails toward the lower energies. This tail effect is caused, in part, by Compton scattering, by gamma ray absorption events that do not confine all charge creation to within a single pixel and by non-ideal charge collection. Because the illustrated response function represents the distribution of measured signals from only a single pixel, charge that is lost from the pixel and shared with adjacent pixels is not included in the response fuinction. As a result, gamma ray absorption events in which the charge collection is incomplete due to charge sharing with other pixels are lost from the peak region and contribute to the low energy tailing. [0016] FIG. 2 is a cross-sectional elevation view of an exemplary imaging device detector 100 in accordance with one embodiment of the present invention and includes a plurality of pixilated semiconductor detector elements 102 that may be used in connection with, for example, localizing a radiation interaction event in the detector. In the exemplary embodiment, detector 100 includes a detector substrate 104 and a collimator 106 . Detector 100 may be formed of a radiation responsive semiconductor material, for example, cadmium zinc telluride (CZT) crystals. Detector elements 102 may be formed of the substrate 104 by pixelating a corresponding plurality of pixel electrodes 108 coupled to a first surface 110 of detector substrate 104 (shown as a lower surface). A cross-sectional size and shape of pixel electrodes 108 and a spacing between each of the pixel electrodes 108 facilitates determining a location and size of each pixilated detector element 102 . Specifically, each pixilated detector element 102 is located proximate a second surface 112 (shown as an upper surface) of detector substrate 104 in substantial alignment with a longitudinal axis 114 of a corresponding pixel electrode 108 . Each pixilated detector element 102 includes a central region 116 , bounded by useful limits 118 , defining an operating portion, and a region of variable response 119 . Within central region 116 , pixilated detector element 102 has a substantially uniform and repeatable response characteristic to radiation incident on second surface 112 . Detector substrate 104 in areas outside central region 116 has a response characteristic to radiation incident on second surface 112 that may be variable. An intrinsic spatial resolution of detector 100 may be defined by the size of and the spacing between each pixilated detector element 102 . Because, pixilated detector elements 102 may be non-homogeneous in response and because central region 116 has a substantially uniform and repeatable response characteristic, collimator 106 may be formed to allow gamma and x-ray photons to interact with central region 116 and to block gamma and x-ray photons from reaching region of variable response 119 . [0017] Collimator 106 includes septa 120 that define apertures 122 through the collimator. A degree of collimation may be defined by a length 124 of collimator 106 , a diameter 126 of apertures 122 , a thickness 128 of apertures 122 , and an absorption coefficient of the material collimator 106 from which collimator 106 is fabricated. A surface 130 of collimator 106 that is proximate second surface 112 defines a gap 132 between detector substrate 104 and collimator 106 . A collimating mask 134 may abut and/or be coupled to second surface 112 and cover region of variable response 119 . In one embodiment, collimating mask 134 is adhered to second surface 112 . In another embodiment, collimating mask 134 is deposited on second surface 112 for example by using a vapor deposition process. A thickness 136 of collimating mask 134 may be determined based on an energy level of photons that may be incident on collimating mask 134 in operation, and an absorption coefficient of the material from which collimating mask 134 is fabricated. For example, collimating mask 134 may be fabricated from a relatively high atomic number material (e.g., an atomic number of about seventy-two or greater) that can absorb radiation of the type intended to be employed in imaging device detector 100 , such as, for examples, lead and tungsten or alloys or conglomerates thereof. [0018] In operation, photons, for example emission gammas and transmission x-rays, from a source 140 are directed towards second surface 112 . A first portion 144 of the photons may arrive at an incident surface 142 of collimator 106 substantially parallel with septa 120 and in alignment with apertures 122 , and pass through collimator 106 without substantial interaction with collimator 106 . A second portion 146 of the photons may arrive at incident surface 142 of collimator 106 substantially parallel and in alignment with septa 120 and may interact with collimator 106 by absorption or scattering. A third portion 148 of the photons may arrive at incident surface 142 of collimator 106 at an angle 150 with respect to a longitudinal axis 152 of aperture 122 . If angle 150 is greater than an angle determined by length 124 and diameter 126 , a photon entering aperture 122 will interact with collimator 106 before exiting aperture 122 . If angle 150 is less than the angle determined by length 124 and diameter 126 , the photon may exit aperture 122 so as to interact with collimating mask 134 covering region of variable response 119 . Accordingly, collimating mask 134 facilitates preventing photons, that would otherwise interact with region of variable response 119 , from doing so. [0019] Second surface 112 may be substantially covered by a single cathode electrode 154 . First surface 110 has a rectangular array of small, for example between about one millimeters squared (mm 2 ) and about ten mm 2 , generally square pixel electrodes 108 configured as anodes. A voltage difference applied between pixel electrodes 108 and cathode 154 during operation generates an electric field (detector field) in substrate 104 . The detector field may be, for example, about one kilovolts per centimeter to three kilovolts per centimeter. Although pixel electrodes 108 are described in the exemplary embodiment as being generally square, this shape should not be understood to be limiting, in that other shapes of pixel electrodes 108 are contemplated. [0020] When a photon is incident on substrate 104 , it generally loses all its energy in substrate 104 by ionization and leaves pairs of mobile electrons 156 and holes 158 in a small localized region of substrate 104 . As a result of the detector field, holes 158 drift toward cathode 154 and electrons 156 drift toward pixel electrodes 108 , thereby inducing charges on pixel electrodes 108 and cathode 154 . The induced charges on pixel electrodes 108 are detected and identify the time at which a photon was detected, how much energy the detected photon deposited in the substrate 104 and where in the substrate 104 the photon interaction occurred. [0021] To facilitate optimum detection of gamma and x-ray photons, central region 116 should be in substantial alignment with apertures 122 , collimating mask 134 should be in substantial alignment with septa 120 , and the relative dimensions of gap 132 , length 124 , diameter 126 and thickness 128 should be determined such that photons arriving at incident surface 142 are absorbed in collimator 106 , collimating mask 134 , or central region 116 . [0022] FIG. 3 is a perspective view of imaging device detector 100 (shown in FIG. 2 ). Imaging device detector 100 includes detector substrate 104 with high voltage cathode 154 covering substantially the entire second surface 112 . A dielectric layer 302 is positioned over high voltage cathode 154 to insulate the high voltage applied to high voltage cathode 154 during operation from electrical and/or other components of imaging device detector 100 . In the exemplary embodiment, dielectric layer 302 comprises Kapton™ film of about 0.01 mm to about 0.5 mm in thickness. In an alternative embodiment, other thin film dielectrics may be used, such as, but not limited to, Mylar™. Collimating mask 134 is applied to dielectric layer 302 . Collimating mask 134 includes a plurality of mask openings 304 separated by mask septa 306 . Mask openings 304 are shown, generally, as square openings, but may be fabricated as other shapes, such as hexagonal and round to meet specific requirements. Collimating mask thickness 136 may be selected to substantially reduce incident photons from interacting with region of variable response 119 and may be, for example, about one mm to six mm. If collimating mask 134 is fabricated from lead or tungsten, a typical collimating mask thickness 136 may be three mm to five mm. Thickness 136 may also be selected such that collimating mask 136 acts as a general purpose collimator, allowing imaging without using collimator 106 for certain scans, and allowing use with collimator 106 for relatively higher resolution scans. In various exemplary embodiments, a width 308 of mask septa 306 may be, for example, about 0.1 mm to about 0.5 mm. [0023] In another embodiment, dielectric layer 302 may be removed, in which case, collimating mask 134 is held at a high voltage cathode voltage and insulated from surrounding low voltage components by, for example, an airgap, a dielectric coating, a dielectric layer, and/or dielectric components, such as paint, tape, and plastic parts. [0024] Collimator 106 includes the plurality of apertures 122 separated by collimator septa 120 . In the exemplary embodiment, a pitch 310 of mask openings 304 and septa 306 of collimating mask 134 is substantially equal to a pitch (not shown) of central region 116 and region of variable response 119 (both shown in FIG. 2 ). As used herein, pitch refers to a distance between identical features of a recurring pattern, for example, a distance between adjacent apertures 122 measured from a center of a first aperture 122 to a center of an adjacent aperture 122 . In various exemplary embodiments, a pitch of apertures 122 and collimator septa 120 is about equal to the pitch of collimating mask 134 . Due to a close coupling of collimating mask 134 to detector substrate 104 , the pitch of collimator 106 may deviate from the pitch of collimating mask 134 without substantially affecting the performance of imaging device detector 100 . [0025] FIG. 4 is a schematic side elevation of a portion of imaging device detector 100 (shown in FIG. 2 ). FIG. 4 illustrates alignment tolerances between collimator 106 and collimating mask 134 . Collimating mask septa 306 are fabricated such that they are positioned adjacent region of variable response 119 and may be fabricated to a width 402 that is wider than a width 404 of region of variable response 119 and collimating mask septa 306 . Accordingly, this accommodates when collimator septa 306 may be offset a distance 403 , due to lateral misalignment of collimator 106 with respect to detector substrate 104 , a variation in collimator pitch from that of collimating mask 134 , or other reason. The amount of offset, variation, or tolerance provided is determined by width 402 , width 404 , width 128 , and gap 132 . To improve the spatial resolution of imaging device detector 100 , one or more additional stacking collimators (not shown) may be stacked on incident surface 142 of collimator 106 to effectively increase length 124 . Accordingly, system 100 including collimating mask 134 may be supplied with a factory-determined sensitivity map. Using the various exemplary embodiments described herein, collimator 106 and other additional collimators may be added without substantially changing the sensitivity map. [0026] FIG. 5 is a schematic illustration of an exemplary array 500 of imaging device detectors 100 configured to couple to an arcuate base. Each imaging device detector 100 may be staggered or vertically incremented relative to each adjacent imaging device detector 100 to accommodate various mounting configuration requirements. Alternately, imaging device detectors 100 may be aligned with each adjacent imaging device detector 100 to accommodate mounting in a flat panel configuration. [0027] The above-described imaging device detectors provide a cost-effective and reliable means for examining a patient. More specifically, the imaging system includes a collimating mask that is closely coupled to the surface of a planar pixilated semiconductor detector to facilitate reducing photon interaction in a region of variable response of the detector pixels. Coupling a collimating mask directly to the surface of the detector also facilitates improving the semiconductor (e.g., CZT) detector response energy spectrum, for example, reducing the characteristic tail, increasing detector imaging efficiency or the ability to tradeoff detector efficiency for higher spatial resolution, reducing response to scatter relative to direct photons (e.g., gammas and x-rays), reducing collimator handling, facilitating and simplifying collimator exchange, permitting “turn key” operation, and allowing for pre-calibration of the detector system at the factory before delivery to a customer. [0028] Exemplary embodiments of pixilated photon detector methods and apparatus are described above in detail. The pixilated photon detector components illustrated are not limited to the specific embodiments described herein, but rather, components of each pixilated photon detector may be utilized independently and separately from other components described herein. For example, the pixilated photon detector components described above may also be used in combination with different imaging systems. A technical effect of the various embodiments of the systems and methods described herein include at least one of improving the semiconductor detector response energy spectrum by reducing the characteristic tail of the response and permitting simpler and easier exchange of collimators. [0029] While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.	A method of detecting ionizing radiation is provided. The method includes pixelating a semiconductor substrate such that each pixel comprises a central region and a region of variable response, substantially blocking the ionizing radiation from reaching the region of variable response, and receiving the ionizing radiation with the central region.	6
BACKGROUND OF THE INVENTION The present invention relates to ferroelectric memories, and, more particularly, to self-referencing schemes for a 1T/1C ferroelectric memory in which the memory cell itself serves as a reference for determining the stored memory state. Nonvolatile ferroelectric random access memories (FRAM®— trademark of Ramtron International Corporation of Colorado Springs, Colo.) realize the memory function by the use of two different polarization states (generally referred to as “up” and “down” polarizations) in the ferroelectric cell capacitors, which are used to distinguish between a logic zero and a logic one data state. It has long been a key issue to build reliable memory references that can be used to distinguish between the two polarization states in a 1T/1C cell structure. There are two existing types of “stand-alone” memory references: voltage references and capacitance references. Both of these types of references are susceptible to the variations in the quality, the dimensions, and the remanent polarizations of the ferroelectric films used in the memory cells. Even for an initially uniform memory array, non-uniform operations on the memory cells introduce substantial fluctuations in the ferroelectric properties of the ferroelectric films in the memory cells, due to uncontrollable effects such as polarization imprint and fatigue in the ferroelectric films. In addition, if the reference cells are built with the same ferroelectric materials, the reference cells will suffer much more imprint and fatigue than memory cells since the reference cells experience many more accesses. This therefore limits the reliability and endurance of the FRAM memory. In a 1T/1C ferroelectric memory with stand-alone reference cells, one reference is shared by memory cells in a segment or a section. The reference level must be always between the minimum of the bit line voltages corresponding to the logic one data state and the maximum of the bit line voltages corresponding to the logic zero data state among these memory cells. However, both the minimum and the maximum changes with processing variations, temperature, and time. Even for an originally uniform array, the array will lose its uniformity during real operations since cells usually experience different access frequencies. Furthermore, the reference level also shifts with time and temperature. Because of these uncontrollable and unpredictable variations, it is extremely difficult to build a reference that works reliably for all the specified time and temperature ranges. What is desired, therefore, is a robust self-referencing circuit and method for a 1T/1C ferroelectric memory array that overcomes the inherent performance limitations of the existing stand-alone voltage and capacitive references. SUMMARY OF THE INVENTION According to the present invention, a circuit and method is disclosed for reading data from a 1T/1C nonvolatile ferroelectric random access memory without using any stand-alone reference circuits. The polarization state in a given 1T/1C memory cell in an array is determined by applying two consecutive plate pulses on the ferroelectric capacitor in the memory cell, preamplifying the bit line voltages corresponding to these two plate pulses, and comparing the preamplified voltages. The two consecutive plate pulses have the same polarity. The storage information in a ferroelectric memory cell is read out by comparing the responses of the same cell to two consecutive plate line pulses. The self-reference scheme of-the present invention substantially reduces the requirement on the uniformity of the ferroelectric films in the memory cells. All the reliability issues related to stand-alone reference cells are eliminated because no stand-alone reference is used. Thus, the reliability of the memory is substantially enhanced. In addition, the worst case condition in a 1T/1 C FRAM memory with stand-alone reference cells is when an opposite “P” term and an opposite “U” term exist in an array because the margin between “P” and “U” terms becomes minimal in this case. This situation will not be an issue in the self-referencing scheme of the present invention because these two terms are not compared when the ferroelectric capacitor in a memory cell is driven by two plate pulses in the same direction. Although the self-referencing scheme eliminates the problems mentioned above, the signal margin on the bit lines are as small as those in 1T/1C FRAM memories using stand-alone reference cells. The signal margin on the bit lines decreases as the bit-line-to-cell ratio increases. This puts a limitation on the density of the FRAM memories. However, the present invention provides a way to greatly increase the signal margin by combining the self-referencing scheme with preamplifiers. There is only one signal path per bit line with the self-referencing scheme of the present invention while there are two signal paths per bit line in a 1T/1C FRAM memory using stand-alone reference cells (one from the bit line and the other from the reference). Thus, a preamplifier can be safely used only with the self-referencing scheme. Using preamplifiers to increase the signal margin is an advantage that uniquely belongs to the self-referencing scheme. The area efficiency of the memory layout is increased by using the self-referencing scheme and preamplifiers. Firstly, the bit line can be built much longer because of the increased signal margin. Secondly, there are no reference cells with associated control circuits, which add substantial area in a 1T/1C FRAM memory layout. Operating speed is not reduced when compared to that of an equivalent 1T/1C FRAM memory using stand-alone reference cells. In the self-referencing scheme of the present invention, two plate line pulses are applied to the ferroelectric cell capacitors during a reading operation. In a 1T/1C FRAM memory using stand-alone reference cells, one plate line pulse is applied. However, the time required to pre-charge the reference cells and the reference bit lines plus the time taken by the control circuits for the reference cells may even take longer time than an extra plate pulse. The foregoing and other objects, features and advantages of the invention will become more readily apparent from the following detailed description of a preferred embodiment of the invention, which proceeds with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of the self-referencing memory of the present invention; FIG. 2 is an illustration of reading a ferroelectric memory cell having downward polarization with reference to a section of a hysteresis loop; FIG. 3 is an illustration of reading a ferroelectric memory cell having upward polarization with reference to a section of a hysteresis loop; FIG. 4 is a timing diagram with simulated voltage and control waveforms for reading a logic “one” data state from a 1T/1C ferroelectric memory cell; FIG. 5 is a timing diagram with simulated voltage waveforms for reading a logic “zero” data state from a 1T/1C ferroelectric memory cell; and FIG. 6 is an illustration of a full 1T/1C memory array structure using the self-referencing scheme and preamplifiers of the present invention. DETAILED DESCRIPTION Referring now to FIG. 1, a 1T/1C self-referencing FRAM memory 10 , an associated preamplifier 12 , and an associated sense amplifier 14 are shown. A ferroelectric capacitor CF and a MOSFET transistor MO comprise a ferroelectric memory cell. The gate of transistor MO is connected to a word line WL, which controls the access to the memory cell. A plate line PL is connected to one of the electrodes of the ferroelectric capacitor CF. Capacitor CL represents the bit line capacitance. Capacitor CADD is a capacitor which is connected to the bit line through transistor M 3 during the first plate line pulse in a reading operation. The bit line is connected to the input of a voltage preamplifier 12 . The preamplifier is an analogue amplifier with a single ended input and a single-ended output, while the “sense amplifier” 14 has two input terminals VOUT 1 and VOUT 2 and its output voltages are digital signals VDD and GROUND. The bit line is connected to a voltage preamplifier 12 , which is to be distinguished from “sense amplifier” 14 for comparing voltages VOUT 1 and VOUT 2 . There are two capacitors C 1 and C 2 with the same capacitance, which are connected to the output of the preamplifier through two transistors M 1 and M 2 . In a writing operation, the bit line BL is pulled up to the source voltage and the plate line PL is connected to ground to program the polarization in the ferroelectric capacitor downward. The plate line PL is pulled up to the source voltage and the bit line BL is connected to ground to program the polarization upward. In a reading operation, the plate line PL is driven by two consecutive positive voltage pulses. Before each of the plate line pulses is applied, the bit line BL is discharged to ground and then floated. During the first plate line pulse, transistors Ml and M 3 are turned on and transistor M 2 is turned off. During the second plate line pulse, transistors Ml and M 3 are off and transistor M 2 is on. The bit line voltage VBL is amplified by preamplifier 12 and the output voltages during the two plate line pulses are sampled into capacitors Cl and C 2 , respectively. The voltages on capacitors Cl and C 2 are fed into sense amplifier 14 after the two plate line pulses to resolve a valid data state. FIGS. 2 and 3 illustrate the charge changes on the ferroelectric capacitor CF under the two plate line pulses for initially downward and upward polarizations, respectively. Partial hysteresis loops are used to show the change in charge. In FIG. 2, the polarization is initially downward at point A. The charge change on the ferroelectric capacitor CF is designated Q 1 (Q 1 is conventionally called the “P” term) during the first plate line pulse and designated Q 2 during the second plate line pulse. For the downward polarization case, Q 1 is much larger than Q 2 . Thus, the bit line voltage VBL during the first plate line pulse is higher than the bit line voltage VBL during the second plate line pulse, although the load capacitor CADD is added to the bit line BL only during the first plate line pulse. This difference is increased after the bit line voltages are amplified by preamplifier 12 . The amplified voltages are sampled into capacitors C 1 and C 2 as previously explained. The voltages on capacitors C 1 and C 2 are then fed into sense amplifier 14 for further amplification and to resolve a valid data state. In FIG. 3, the polarization is initially upward at point A. In this case, the Q 1 and Q 2 charges after each plate line pulse are close in value (Q 1 is conventionally called the “U” term). However, the load capacitor CADD is connected to the bit line only during the first plate line pulse. Capacitor CADD is chosen in such a way that the bit line voltage VBL during the first plate line pulse is lower than the bit line voltage during the second plate line pulse for this case. As in the previous case, the two VBL voltages are amplified by preamplifier 12 , sampled into capacitors C 1 and C 2 , and fed into sense amplifier 14 . The ratio of CADD/CL is chosen to optimize the signal margins for both cases. In the following two tables, Vb 11 is the bit line voltage after the first plate line pulse is administered and Vb 12 is the bit line voltage after the second plate line pulse is administered. The next voltage term, ΔVb 1 , is the signal margin on the bit line, i.e. (Vb 11 −Vb 12 ). Vout 1 is the output voltage from preamplifier 12 input to sense amplifier 14 on the first plate line pulse. Vout 2 is the output voltage from preamplifier 12 to sense amplifier 14 on the second plate line pulse. The final voltage term, ΔVout, is the signal margin to sense amplifier, i.e. (Vout 2 −Vout 1 ). The terms normal, weak, and strong refer to normal, poor, and good processing on silicon, respectively. The voltages given refer to the power source voltages to the circuit, i.e. VDD or VCC in the conventional notations. The temperatures listed are the simulated operating temperature in degrees Centigrade. The voltages and voltage differences in the tables are measured in millivolts. Table I shows the simulation results for a ferroelectric memory with 512 word lines connected to each bit line for a read operation of a data one logic state: Read “1” Vb11 Vb12 ΔVb1 Vout1 Vout2 ΔVout 27 C., Normal, 1.3 V 212 120 92 51 289 238 105 C., Weak, 207 119 88 54 406 352 1.235 V −45 C., Strong, 213 124 89 64 363 299 1.365 V −45 C., Normal, 206 120 86 64 318 254 1.235 V 105 C., Strong, 213 123 90 213 722 509 1.365 V Table II shows the simulation results for a ferroelectric memory with 512 word lines connected to each bit line for a read operation of a data zero logic state: Read “0” Vb11 Vb12 ΔVb1 Vout1 Vout2 ΔVout 27 C., Normal, 1.3 V 84 117 −33 542 308 −234 105 C., Weak, 83 112 −29 545 344 −201 1.235 V −45 C., Strong, 87 121 −34 598 377 −221 1.365 V −45 C., Normal, 82 114 −32 457 318 −139 1.235 V 105 C., Strong, 85 120 −35 917 731 −186 1.365 V A self-referencing ferroelectric memory has been shown for use with a 1T/1C memory cell structure. Two pulses are applied to the same plate line and the corresponding charges are transferred to the same bit line. In the pulsing scheme of the present invention, the opposite “P” term will never be compared with the opposite “U” term since the two pulses are applied on the ferroelectric capacitor in the same direction. There is only one signal path in the self-referencing memory of the present—the bit line BL. The use of only one signal path is critically important to making the self-referencing scheme work because the preamplifier can be safely used only with one signal path. The difference between the bit line voltages during the two pulses is about 90 mV for reading a logic one and about 30 mV for reading a logic zero. These margins decrease with time. However, after being pre-amplified, the differential signals to the sense amplifier are at least 238 mv and 139 mV for reading logic one and zero, respectively. Referring now to FIGS. 4 and 5, a memory access starts with address decoding. After a word line WL is selected from address decoding, the word line WL is pulled high at about 5 ns. The bit line is floated by pulling the bit line pre-charge control signal BLPRC low. (See FIG. 6 for the location of the BLPRC signal line 26 in a memory array.) After the bit line is floated, the plate line PL is pulled high to apply the first plate line pulse to the ferroelectric capacitor in the memory cell, and READ 1 is pulled high to sample the output voltage VOUT 1 from the preamplifier during the first plate line pulse. During the first plate line pulse, CTL is high to add the load capacitor CADD to the bit line. READ 1 is pulled low to shut down the transistor Ml before the plate line PL becomes low. Then, BLPRC becomes high to pre-charge the bit line to ground and CTL becomes low to disconnect the load capacitor CADD from the bit line. Then, BLPRC is low to float the bit line and the plate line PL is high again to apply the second plate pulse to the ferroelectric capacitor in the memory cell. At almost the same time, READ 2 is pulled high to sample the output voltage VOUT 2 from the preamplifier during the second plate pulse. Finally, VOUT 1 and VOUT 2 are fed into a sense amplifier to resolve the data state. The simulation results shown in FIGS. 4 and 5 are for a design in which CL is about 0.42 pF, CADD is 60% of CL, C 1 and C 2 are 0.04 pF, CF is about 0.28 μm 2 , and the W/L of MO is 0.4/0.15 μm. For our ferroelectric thin films, 60% of CL is the optimum value for CADD. The waveforms VOUT 1 , VOUT 2 , and VBL shown in FIGS. 4 and 5 are the outputs from the preamplifier and the bit line voltage for reading a stored “one” and “zero”, respectively. The control signals are the same for both cases. Referring now to FIG. 6 the structure of a 1T/1C ferroelectric memory array 20 with the self-referencing scheme and preamplifiers 12 of the present invention is shown. At the top of the array 20 are sense amplifiers 14 . The sampling capacitors and their control signals READ 1 and READ 2 are right under the sense amplifiers 14 . Under these cells are preamplifiers 12 , and the load capacitors added to the bit lines controlled by CTL. The bit line pre-charge line 26 is at the bottom of array 20 . Between CTL and BLPRC is the actual 1T/1C memory cell array. Each memory cell is constructed by one ferroelectric capacitor and one transistor. The gate of the transistor is connected to a world line WL 0 -WL 511 . One of the electrodes of the ferroelectric capacitor is connected to a plate line PL 0 -PL 512 and the other is connected to the source of the transistor. World lines WL 0 -WL 512 are controlled by word line decoders and drivers 24 and the plate lines are controlled by plate line controllers and drivers 22 . The controllers for other signals are omitted for simplicity. In operation, the load CADD capacitor is added to the BL bit line only during the first plate line pulse. There are three purposes in doing this. First, recall that in the self-referencing scheme of the present invention that the charge transferred onto the bit line BL for an original downward polarization, i.e. a P term, is always larger than that for an original upward polarization, i.e. a U term. Thus, the voltage applied to the ferroelectric memory cell capacitor CF for a data one state is smaller than that for a data zero state during the first plate line pulse. This data-dependent voltage applied on the ferroelectric capacitor is not desirable. The addition of a load capacitor to the bit line BL during the first plate line pulse reduces this difference. Second, the margins between reading a logic one and a logic zero can be optimized by adjusting the capacitance of the load capacitor. Third, by adding a capacitor to a bit line, the self-referencing scheme is realized before the preamplifier. The feeding circuit to the sense amplifier is therefore balanced between its two sides. The load on the two sides of the sense amplifier can be well balanced since a threshold on the inputs to the sense amplifier is not needed and the preamplifier isolates the sense amplifier from the bit line. By using the preamplifiers, the signal margins are significantly increased. The self-referencing scheme without the preamplifiers has small signal margins, especially when the bit-line-to-cell ratios are high, and thus is not suitable for high-density memories. The self-referencing scheme combined with preamplifiers provides a reliable and robust way to implement high density ferroelectric memories. Having described and illustrated the principle of the invention in a preferred embodiment thereof, it is appreciated by those having skill in the art that the invention can be modified in arrangement and detail without departing from such principles. For example, while a 512×64 memory array has been shown, it is apparent to those skilled in the art that other density memory arrays can be used. I therefore claim all modifications and variations coming within the spirit and scope of the following claims.	An implementation of 1T/1C nonvolatile ferroelectric RAMS without using any reference cells—the polarization state in a memory cell is determined by applying two consecutive plate pulses on the ferroelectric capacitor in the memory cell, preamplifying the bit line voltages corresponding to these two plate pulses, and comparing the preamplified voltages. The two consecutive plate pulses have the same polarity.	6
BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a gain control circuit and method in which parallel-arranged differential pairs are unbalanced as a function of a gain control signal. The invention also relates to receivers which incorporate such a gain control circuit. 2. Description of the Related Art International Application PCT/IB95/00848, corresponding to U.S. patent application Ser. No. 08/543,731, filed Oct. 16, 1995 (attorney docket PHN 15,068), now U.S. Pat. No. 5,742,203, describes a prior-art gain control circuit of the above type. In the prior-art gain control circuit, a number (N) of parallel arranged differential pairs constitutes a transadmittance stage. This means that an input voltage is commonly applied between the bases of the differential pairs, and an output current is taken from mutually coupled collectors of these differential pairs. The gain of this transadmittance stage is varied by unbalancing the differential pairs to a larger or smaller extent. For a maximum gain, all of the differential pairs are balanced in such a way that their transfer characteristics overlap. In that case, the gain of the transadmittance stage is equal to the gain of each individual differential pair multiplied by the number (N) of differential pairs. For a minimum gain, the differential pairs are unbalanced in such a way that the transfer characteristics do not substantially overlap. In that case, the gain of the transadmittance stage is approximately equal to the gain of an individual differential pair. For a certain gain between maximum and minimum, the differential pairs are unbalanced in such a way that their transfer characteristics overlap to a certain extent. The prior-art gain control circuit can be used to bring the amplitude of an input signal to a desired level. The gain is relatively high when the input signal amplitude is relatively low, and vice versa. The linear range of the prior-art gain control circuit changes with the gain in a desired fashion. When the gain is relatively high, the linear range seen at the input is smallest. This is in accordance with the relatively low input signal amplitude. Conversely, when the gain is relatively low, the linear range seen at the input is relatively wide, such that it is accommodated to the relatively high amplitude input signal. Thus, the linear range of the prior-art gain control circuit changes in accordance with the input signal amplitude. This helps to keep the distortion relatively low throughout the gain control range of the gain control circuit. SUMMARY OF THE INVENTION It is an object of the invention to provide a gain control which, with respect to the prior-art, is even more favorable in terms of both distortion and noise. To this end, a first aspect of the invention provides a gain control circuit comprising a plurality of parallel-arranged differential pairs which have mutually coupled control terminals for receiving an input signal, and mutually coupled main current terminals for furnishing an output signal, and means for unbalancing the differential pairs as a function of a gain control signal, characterized in that the unbalancing means are arranged to increase or decrease the gain of individual differential pairs when the unbalance of these pairs is decreased or increased, respectively, and characterized in that the gain control circuit forms part of a semiconductor body and that the mutually coupled control terminals of the plurality of differential pairs form part of a base region having two connections for supplying a current thereto for unbalancing the differential pairs as a function of the gain control signal from which the current is derived by the unbalancing means. A second aspect of the invention provides a gain control method employing a plurality of parallel-arranged differential pairs which have mutually coupled control terminals for receiving an input signal and mutually coupled main current terminals for furnishing an output signal, the method comprising the step of unbalancing the differential pairs as a function of a gain control signal, characterized by the step of increasing or decreasing the gain of individual differential pairs when the unbalance of these pairs is decreased or increased, respectively. A third aspect of the invention provides a receiver having an amplification circuit for amplifying a reception signal, the amplification circuit comprising a gain control circuit as defined above. The invention takes the following aspects into consideration. There is an optimal state of unbalance for each particular input signal amplitude, in terms of noise and distortion. If the unbalance is too large, the input signal will not sufficiently drive each differential pair and, consequently, the noise will be unnecessarily high. However, if the unbalance is too small, the input signal will no longer fit in the linear range seen at the input and, consequently, the distortion will be unnecessarily high. In many applications, the gain control circuit is part of a gain control loop which seeks to bring the output signal amplitude to a desired level. Consequently, the input signal amplitude is inversly proportional to the gain. Thus, the noise and distortion behavior of the gain control circuit depend on the relation between the gain and the state of unbalance of the differential pairs. In accordance with the invention, the gain of individual differential pairs is reduced when the unbalance is increased, and vice versa. Thus, the gain is reduced or increased not only by a respective increase or reduction of the unbalance of the differential pairs, but also by a respective reduction or increase of the gain of the differential pairs individually. Accordingly, compared to the prior-art, the unbalance varies to a smaller extent with the gain. Furthermore, the extent of variation can be adjusted, whereas in the prior art the relation between linear range width and gain is fully fixed. Compared with the prior art the aforementioned two aspects allow a significantly better approximation of the optimal linear range throughout the gain control range, and thus, a significantly better performance in terms of noise and distortion. In addition to a favorable noise and distortion behavior, some further advantages of the invention are as follows. One further advantage is that the relation between gain and gain control signal is more or less logarithmic. Another further advantage is that the gain control range is relatively large. The invention also provides a receiver in which a reception signal is amplified by means of the above-identified gain control circuit. The favorable noise and distortion behavior of the gain control circuit promotes a good reception quality. The invention and additional features, which may be optionally used to implement the invention to advantage, are apparent from and will be elucidated with reference to the examples described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: FIG. 1 shows, in a circuit diagram form, an example of a gain control circuit in accordance with the invention; FIG. 2 shows, in a single graph, the gain control and distortion characteristic of an implementation of the FIG. 1 gain control circuit; FIG. 3 shows, in the form of a lay-out sketch, an example of an integrated circuit implementation of the FIG. 1 gain control circuit; and FIG. 4 shows, in a block diagram form, a receiver in accordance with the invention. Like elements have like reference signs throughout the drawings. DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of a gain control circuit GCC in accordance with the invention. The FIG. 1 gain control circuit amplifies a differential input signal Vin to produce a differential output signal Vout. The amount of amplification is controlled by a gain control voltage Vagc. The FIG. 1 gain control circuit can be functionally divided into two parts: a signal-handling part SHP and a bias control part BCP. The core of the signal-handling part SHP is formed by a number N of differential pairs DP1,DP2 . . . DPN which are arranged in parallel. The differential pairs DP1,DP2 . . . DPN receive the differential input signal Vin between their bases via buffer transistors Tb and Tb'. The output signal Vout is taken from the collectors of the differential pair DP1,DP2 . . . DPN. Two DC biasing parameters are adjusted to set the gain at a certain level: an offset voltage Vdelta between two consecutive differential pairs and tail currents I1,12 . . . IN supplied to the common emitters of the differential pairs DP1,DP2 . . . DPN. The offset voltage Vdelta is the result of two offset currents Idelta and Idelta' which flow through two strings of base interconnection resistances Rb1 . . . RbN and Rb1' . . . RbN', respectively. The bias control part BCP effectively translates the gain control voltage Vagc into the two offset currents Idelta and Idelta' and the tail currents I1,I2 . . . IN. In the bias control part BCP, a differential pair DC divides a current ISagc into two portions. The magnitudes of these portions depend on the value of the gain control voltage Vagc with respect to a reference voltage Vref. A first current mirror CM1 derives the offset currents Idelta and Idelta' from one portion, and a second current mirror CM2 derives the tail currents I1,I2 . . . IN from the other portion. If the gain control voltage Vagc is substantially higher than the reference voltage Vref, almost the entire current ISagc will be used for the tail currents I1,I2 . . . IN, whereas the offset currents Idelta and Idelta' and, consequently, the offset voltage Vdelta will be practically nil. In that case, each individual differential pair DP1,DP2 . . . DPN in the signal-handling part will have a maximal gain and the transfer characteristics of the differential pairs DP1,DP2 . . . DPN will substantially overlap. Accordingly this setting, the signal-handling part SHP has a maximal gain. If, starting from the above condition, the gain control voltage Vagc is reduced, the following effects will occur. Below a certain gain control voltage Vagc (H), the magnitude of the tail currents I1,I2 . . . IN will start to be less than ISagc, and the offset currents Idelta and Idelta' will start to be different from zero. The gain control voltage Vagc(H) marks the high gain boundary of the gain control range. If the gain control voltage is further reduced, the tail currents I1,12 . . . IN will decrease, whereas the offset currents Idelta and Idelta' and, consequently, the offset voltage Vdelta, will increase. A decrease of the tail current reduces the gain of the individual differential pairs DP1,DP2 . . . DPN and, consequently, reduces the gain of the signal handling part SHP as a whole. An increase of the offset voltage Vdelta reduces overlap between transfer characteristics of the differential pairs DP1,DP2 . . . DPN. This has a twofold effect on the signal-handling part SHP: it widens the linear range width seen at the input and further reduces the gain in addition to gain reduction due to the decrease of the tail currents I1,12 . . . IN. Thus, in the FIG. 1 gain control circuit, the gain is reduced by increasing the unbalance between the differential pairs DP1,DP2 . . . DPN and by decreasing the gain of the individual differential pairs. The linear range width is affected by the unbalance between the differential pairs only. Accordingly, a relation between gain and linear range width can be obtained which is favorable in terms of noise and distortion. FIG. 2 shows gain control and distortion characteristics of the FIG. 1 gain control circuit. The gain control voltage Vagc is plotted on the horizontal axis. The gain--or amplification factor--G is plotted on the left-hand vertical axis which has a logarithmic scale. The gain-versus-control voltage characteristic is shown as curve G. The third-order intercept point at the output (IP3out) is plotted on the right-hand vertical axis in decibel-microvolt (dBuV). The distortion-versus-control voltage characteristic is shown as curve D. Arrows indicate to which vertical axis, left or right, a curve refers. FIG. 2 shows that the gain-versus-control voltage characteristic is essentially logarithmic, which is advantageous in many applications. For example, if the gain-versus-control voltage is more or less logarithmic, it will be possible to achieve a gain control of a substantially constant bandwidth with relatively simple circuitry. FIG. 2 further shows that the third-order distortion is relatively low throughout the gain control range and only varies to a little extent. FIG. 3 shows an example of an integrated circuit implementation of the FIG. 1 gain control circuit. In a semiconductor body, two relatively large base regions BR and BR', respectively, are formed. Each base region BR and BR' comprises the following elements: collector contacts C and C', first base contacts BX and BX', second base contacts BY and BY', and a number of N emitter contacts E1,E2 . . . EN and E1',E2' . . . EN', respectively. The emitter, base and collector connections in the FIG. 1 circuit diagram, which correspond to the aforementioned contacts in the FIG. 3 lay-out sketch, have been denoted by the same reference signs. Furthermore, signals which are supplied to these connections in the FIG. 1 circuit diagram are also indicated in FIG. 3. If one compares the FIG. 1 circuit diagram with the FIG. 3 lay-out sketch, the following may be noted. One transistor of each differential pair DP1,DP2 . . . DPN in FIG. 1, is implemented in the base region BR, shown in FIG. 3, by means of emitter contacts E1 . . . EN, respectively, whereas the other transistor is implemented in the base region BR' by means of emitter contacts E1' . . . E2', respectively. Furthermore, the base interconnection resistances Rb1 . . . RbN and Rb1' . . . RbN', shown in FIG. 1, are formed by the semiconductor material in the base regions BR and BR', respectively. In the FIG. 3 implementation, the offset current Idelta flows from the base contact BX to the base contact region BY, and the offset current Idelta' flows from the base contact BY' to the base contact BX'. The offset currents Idelta and Idelta' flowing through the semiconductor base material in the base regions BR and BR', respectively, cause a voltage gradient between the base contacts of each base region. Accordingly, an offset voltage is obtained between locations in the semiconductor base material near two consecutive emitter contacts, which offset voltage corresponds to the offset voltage Vdelta indicated in FIG. 1. FIG. 3 further shows some implementation details of the current mirror CM2 in the FIG. 1 circuit diagram. In the FIG. 3 implementation, the current mirror CM2 is formed by a gate strip GS, a source strip SS and a plurality of drain regions D1 . . . DN which provide tail currents I1,12 . . . IN, respectively. The electrical equivalent of this implementation of current mirror CM2 is an assembly of N MOS-transistors which have mutually coupled gate and source connections, as illustrated in FIG. 1. FIG. 4 shows an example of a receiver incorporating three gain control circuits GCC1, GCC2 and GCC3 of the type shown in FIG. 1. The FIG. 4 receiver comprises two main parts: a tuner TUN and an intermediate-frequency (IF) and demodulation part IFD. The tuner TUN selects and frequency-converts a desired reception signal RF to obtain an intermediate-frequency signal IFS. The intermediate-frequency and demodulation part IFD derives a baseband signal BB from the intermediate-frequency signal IFS. The intermediate frequency and demodulation part IFD may be formed, for example, by one or more integrated circuits in combination with suitably chosen external components. In the intermediate-frequency and demodulation part IFD, the intermediate-frequency signal IFS is brought to a desired level for further processing. To this end, the gain control circuits GCC1, GCC2 and GCC3 are used. The gain control circuits GCC1, GCC2 and GCC3 are arranged in cascade to obtain a sufficiently large gain control range combined with a satisfactory noise and distortion. For example, if each gain control circuit GCC1, GCC2 and GCC3 has a gain control range of 20 dB, within which the noise and distortion are satisfactory, the cascade will have a gain control range of 60 dB. For reasons of conciseness, the manner in which the gain control circuits GCC1, GCC2 and GCC3 are cascaded is not shown in FIG. 4. Those skilled in the art may readily conceive many suitable manners of cascading. For example, suitable buffer and DC level shift circuitry may be coupled between two consecutive gain control circuits. Furthermore, the reference voltage Vref for each gain control circuit GCC1, GCC2 and GCC3 may be chosen to be such that a smooth transition between the gain control ranges of the individual gain control circuits is obtained. It should be noted that the above-mentioned examples illustrate rather than limit the invention, and that those skilled in the art will be able to design may alternative embodiments without departing from the scope of the appended claims.	In a gain control circuit (GCC), a plurality of parallel-arranged differential pairs (DP1,DP2 . . . DPN) is unbalanced as a function of a gain control signal (Vagc). Furthermore, the gain of individual differential pairs (DP1,DP2 . . . DPN) is reduced when the unbalance is increased, and vice versa. Accordingly, a favorable performance in terms of noise and distortion can be obtained.	7
FIELD OF THE INVENTION The present invention relates to a method and apparatus for signal regeneration and a system incorporating the same. BACKGROUND TO THE INVENTION Digital communication equipment is used in a wide variety of devices for the transmission of digital information. Such information includes numerical data in computers and digital encodings of voice in telecommunications systems. In the course of transmission of digital signals from a transmitter to a receiver, the digital signals tend to become degraded. Degradation may involve loss of overall strength of the signal, and loss of definition of the pulse edges: at the time of sending, the pulse edges typically rise and fall sharply with respect to the overall pulse length giving a cleanly defined shape to the pulse whilst, at the receiver, the rate of rise and fall of the pulses tends to decrease resulting in less sharply defined pulses. In order to correct for these degradations, it is common practice to regenerate the original digital signal from the distorted one at the receiving end of a digital communication link. The regenerated signal may then be retransmitted along a further transmission link or be further processed locally. To regenerate a received signal, typically, the receiver must ensure that the received data signal (the data signal) is processed synchronously relative to a local clock signal (the clock signal). It is also necessary to ensure that the amplitude of the data signal is not sampled near the degraded edges of the received data pulses which would lead to incorrect interpretation of the signal. Not only can the data arrive significantly out of phase with the local clock, but minor variations in the frequency of the clock and of the data mean that the phase difference may vary over time. This means that it is necessary not only to identify the phase difference between clock signal and data signal when the data signal is first detected, but also to monitor the phase difference continually while the data signal is being received. By continually monitoring the difference in phase between the data and the clock, it is possible to adjust the arrival time of either the data or the clock (or both) in order to keep the phase difference within acceptable limits. One means of achieving this effect is to incorporate a variable-delay buffer in the data path or clock path (or both) and adjust the buffer length by means of a feedback circuit dependent upon the perceived phase difference between the two signals at a later point in the circuit. For example, if the data appears to lag behind the clock, either the delay in the clock signal path may be increased or that in the data signal path may be decreased. A clock-to-data phase detector is a device which takes as two of its inputs a data signal and a clock signal and generates signals giving information about the phase difference between the data signal and clock signal. A known means of representing the phase difference information is by means of a pair of signals: the first signal (the phase signal) comprises a component which represents the phase difference and a further component which represents the variations in the number of edges occurring in the data; the second signal (the reference signal) represents only the latter variation. Subsequent subtraction of the reference signal from the phase signal gives a signal (the phase difference signal) representing only the difference in phase. Typical existing clock-to-data phase detectors generate a phase difference signal whose pulse duration varies between 0 and 1 clock periods. A problem with existing clock-to-data phase detectors is that non-linearities in the generated phase difference signal occur when the bit rise and fall intervals of the phase difference signal are large relative to the bit period of said data signal. Pulse rise and fall durations are determined by the silicon components used to output the signal. Pulse durations in excess of 0.5 clock periods typically vary linearly with the phase difference of the received data signal. However, as the duration of pulses in the phase difference signal approaches zero so the proportion of the pulse length affected by the rise and fall intervals increases until the rise and fall intervals dominate. Where the rise and fall intervals dominate, pulse durations in the phase difference signal cease to vary linearly with the phase difference of the received data signal. This problem is serious where the data signal bit rate is high relative to the speed at which the phase detector can operate. At high bit rates, for example 110 Gbit/s, the phase detector speed can be constrained by current silicon fabrication technology limits. A further problem arises in phase detectors employing bistables, since each bistable device introduces a propagation delay to the signal passing through it and this delay may vary according to ambient temperature and power supply voltage. Differences in the total delay introduced along distinct paths within a detector can give rise to variations in the relative phase of signals arriving at each subsequent component within the detector. It is known [from C. R. Hogge, "A Self Correcting Clock Recovery Circuit", Journal of Lightwave Technology, Vol. LT-3, No. 6, December 1985] to generate a phase difference signal employing circuitry constructed using silicon components, whilst at the same time generating a reference signal by employing a fixed delay introduced by means of a delay line implemented by means of, for example, a fixed length of coaxial cable or printed circuit board track. However such delay lines do not exhibit the same characteristics with respect to temperature and power supply voltage as do the silicon components and this leads to variations in the relative phase between the phase signal and the reference signal. Whilst it is known to construct a clock-to-clock phase detector which provides a linear phase signal, such a mechanism relies on the regular arrival of pulses in both clock signals. In the case of a clock-to-data phase detector, pulses in the data generally arrive at variable intervals so that such clock-to-clock phase detector methods are not applicable. Regeneration can be achieved by applying threshholding and limiting to the received signal, followed by retiming. Where the data signal arrives at high frequencies or over long distances, it is conventionally retimed using a clock recovered from the data signal. Where the data arrives continuously from a single transmitter, the threshold and phase values can vary over time, but such variation is generally, but not always, gradual. In cases where data arrives in bursts however and particularly, but not exclusively, where successive bursts originate from distinct transmitters, the threshold and phase values can vary enormously between bursts. This in addition to the variation over time within each burst. Where the maximum burst length and frequency deviation within a burst can be limited, it is known [from Wong & Sitch: "A 10 Gb/s ATM Data Synchronizer", IEEE Journal of Solid State Circuits, Vol. 31 No. 109, October 1996] to construct a data synchroniser to resynchronise the received data with the receiver's clock: data transitions of the incoming signal are compared with clock transitions and an error signal is generated if rising and falling transition edges of the data are either both late or both early with respect to the receiver's clock; the error signal so generated is used to adjust the length of a variable length delay buffer present in the data path or clock signal path, thereby effectively bringing the two signals back into alignment. Existing systems minimise modification of the data signal by adjusting the receiver's clock signal to match the data instead. It is also known to construct a re-timing circuit taking as input a data signal to be retimed and a clock signal, and providing as output a retimed copy of the received data signal. This circuit may be constructed, for example, using a single D-type bistable. OBJECT OF THE INVENTION The invention seeks to provide an improved, bandwidth-efficient method and apparatus for acquiring and tracking bursts of data, or continuous data, of varying and unpredictable amplitude, extinction ratio, and phase. SUMMARY OF THE INVENTION According to a first aspect of the present invention, digital signal regenerator is provided, comprising: a threshold adjustment circuit adapted to provide an amplitude-limited data signal upon receipt of a data input signal, a mode input signal, and two phase input signals; a phase adjustment circuit adapted to provide, a first phase output signal derived from the rising edges of the amplitude-limited data signal, a second phase output signal derived from the falling edges of the amplitude-limited data signal, and a delayed data signal, upon receipt of the amplitude-limited data output signal, a mode input signal, and a clock input signal, said phase signals being provided as the phase signals to the threshold adjustment circuit; and a re-timing circuit adapted to provide a retimed data output signal upon receipt of the delayed data signal and a clock input signal. In a preferred embodiment, the threshold adjustment circuit comprises: a first amplifier adapted to provide an amplified data output signal upon receipt of a threshold adjustment input signal and the data input signal; a second amplifier adapted to provide the amplitude-limited data signal upon receipt of the amplified data signal; a subtractor adapted to provide a phase difference output signal representing the difference between the first and second phase output signals; a threshold loop filter adapted to provide a threshold adjustment signal upon receipt of the amplified data output signal, the amplitude-limited output signal, the phase difference output signal, and the mode input signal. Advantageously, the system avoids the use of digital signal processing which is not practical at high data signal rates, for example 10 Gbit/s. According to a further aspect of the present invention, a digital signal regenerator is provided, adapted to receive a continuous digital signal characterised in that both the wander and jitter, measured relative to the clock signal, are within known finite bounds and to regenerate said signal. Advantageously, a system adapted to regenerate a continuous digital signal may be used to receive data signals in accordance with, for example, SONET and/or SDH standards. According to a further aspect of the present invention, a digital signal regenerator is provided, adapted to receive a digital signal consisting of separated bursts of data and to regenerate said signal. Advantageously, the system can acquire the threshold and phase characteristics of a signal very rapidly, and hence is suitable for burst mode data. According to a further aspect of the present invention, a digital signal regenerator is provided, adapted to receive a weak digital signal and to regenerate said signal. According to a further aspect of the present invention, a digital signal regenerator is provided, adapted to receive a weak digital signal consisting of separated bursts of data and to regenerate said signal. According to a further aspect of the present invention, a digital signal regenerator is provided, adapted to receive a data signal having a poor extinction ratio. Advantageously, a system adapted to receive a data signal having a poor extinction ratio, may be employed where the data signal transmitter is a laser or lasers. According to a further aspect of the present invention, a digital signal regenerator is provided, adapted to receive a data signal exhibiting large variations in signal level. According to a further aspect of the present invention, a digital signal regenerator is provided, adapted to obviate extraction of a clock signal from the received data. Advantageously, the number of expensive clock generators required by a signal regenerator is reduced by obviating extraction of a clock signal from the received data. According to a further aspect of the present invention, a digital signal regenerator is provided, adapted to obviate encoding of the data signal using a line code. Advantageously, it thereby extends the existing technology to give a significant increase in data throughput for the same available bandwidth: for example, approximately 33% increase in effective bandwidth is achieved as compared to systems using a 6B8B line code. According to a further aspect of the present invention, a digital signal regenerator is provided, adapted to obviate exercising the data signal channel to track slow drifts. Advantageously, the system may treat each data burst ab initio: it imposes no constraints on the order of bursts, and so there is no need to exercise channels to track slow drifts. According to a further aspect of the present invention, a digital signal regenerator system is provided, additionally comprising a signal format comprising alternate synchronisation parts and data parts. According to a further aspect of the present invention, a digital signal regenerator system is provided, additionally comprising a signal format comprising alternate synchronisation parts and data parts wherein each synchronisation part comprises a period of no signal followed by a period of training pattern. According to a further aspect of the present invention, a digital signal regenerator system is provided, additionally comprising a signal format comprising alternate synchronisation parts and data parts wherein each synchronisation part comprises a period of no signal followed by a period of training pattern exhibiting a high rate of occurrence of rising and falling pulse edges. According to a further aspect of the present invention, a digital signal regenerator system is provided, additionally comprising a signal format comprising alternate synchronisation parts and data parts wherein each synchronisation burst comprises a period of no signal followed by a period of training pattern comprising alternate 1's and 0's. The invention also provides for a system for the purposes of digital signal processing which comprises one or more instances of apparatus embodying the present invention. Advantageously, the system can organise itself without receipt of control signals. The invention is also directed to a method by which the described apparatus operates and including method steps for carrying out every function of the apparatus. Preferrably, a method for digital signal regeneration is provided comprising the steps of: threshold adjustment to provide an amplitude-limited data signal upon receipt of a data input signal, a mode input signal, and two phase input signals; phase adjustment to provide a first phase output signal derived from the rising edges of the amplitude-limited data signal, a second phase output signal derived from the falling edges of the amplitude-limited data signal, and a delayed data signal, upon receipt of the amplitude-limited data output signal, a mode input signal, and a clock input signal, said phase signals being provided as the phase signals to the threshold adjustment step; re-timing to provide a retimed data output signal upon receipt of the delayed data signal and a clock input signal. The invention also provides for a system for the purposes of digital signal processing which comprises one or more instances of apparatus embodying the present invention, together with additional unspecified apparatus. BRIEF DESCRIPTION OF THE DRAWINGS In order to show how the invention may be carried into effect, embodiments of the invention are now described below by way of example only and with reference to the accompanying figures in which: FIG. 1 shows a block diagram of a signal regenerator in accordance with the present invention. FIG. 2 shows a burst data format in accordance with the present invention. FIG. 3 shows a phase detector circuit diagram in accordance with the current invention; FIG. 4 shows a further phase detector circuit diagram in accordance with the current invention; FIG. 5 shows examples of data signals at specific points in the circuit depicted in FIG. 4; FIG. 6 shows an embodiment of phase detector in accordance with the current invention; FIG. 7 shows examples of data signals at specific points in the circuit depicted in FIG. 6; FIG. 8 shows a circuit diagram of another embodiment of a phase detector in accordance with the current invention; FIG. 9 shows examples of data signals at specific points in the circuit depicted in FIG. 8; FIG. 10 shows a block diagram of a further embodiment of a phase detector in accordance with the current invention; FIG. 11 shows a block diagram of a further embodiment of a phase detector in accordance with the current invention; FIG. 12 shows a block diagram of a still further embodiment of a phase detector in accordance with the current invention. FIG. 13 shows an example of an ideal data signal exhibiting neither threshold error nor phase error; FIG. 14 shows an example of a data signal exhibiting a threshold error but no phase error; FIG. 15 shows an example of a data signal exhibiting a phase error but no threshold error; FIG. 16 shows an example of a data signal exhibiting both a threshold error and a phase error; FIG. 17 shows a block diagram of a threshold detector in accordance with the present invention; FIG. 18 shows a block diagram of a combined threshold and phase detector in accordance with the present invention; FIG. 19 shows a block diagram of a threshold tracking system in accordance with the present invention; and FIG. 20 shows a block diagram of a combined threshold and phase tracking system in accordance with the present invention. DETAILED DESCRIPTION OF INVENTION A first embodiment of a signal generator, shown in FIG. 1, comprises a threshold adjustment circuit (1), a phase adjustment circuit (2), and a re-timing circuit (3). The threshold adjustment circuit (1) takes as inputs a data signal, a mode signal, and two phase signals, and provides as outputs an amplitude-limited data signal. The phase adjustment circuit (2) receives as inputs the amplitude-limited data signal output from the threshold adjustment circuit (1), a mode signal, and a clock signal, and provides as outputs a first phase signal derived from the rising edges of the amplitude-limited data signal, a second phase signal derived from the falling edges of the amplitude-limited data signal, and a delayed data signal, said phase signals being provided as the phase signals to the threshold adjustment circuit (1). The re-timing circuit (3) receives as inputs the data signal output from the phase adjustment circuit (2) and a clock signal, and provides as output a retimed data signal. The threshold adjustment circuit (1) itself comprises two amplifiers (10, 11), a subtractor (12), and a threshold loop filter (13). The first amplifier (10) takes as inputs a threshold adjustment signal and the data signal input by the phase adjustment circuit (1) and provides as output an amplified signal. The second amplifier (11) takes as input the signal output required by the first amplifier (10) and provides as output the amplitude-limited data signal output by the phase adjustment circuit (1). The subtractor takes as inputs the phase signals output from the phase adjustment circuit (2), and outputs a signal representing their difference. The threshold loop filter (13) takes as inputs the signal output from the first amplifier (10), the amplitude-limited signal output from the second amplifier (11), the difference signal output from the subtractor (12), and the mode signal input by the threshold adjustment circuit, and outputs the threshold value signal. The phase adjustment circuit (2) comprises a rising edge phase detector (4), a falling edge phase detector (5), a summer (7), a phase loop filter (8), and an adjustable delay (6). The adjustable delay (6) receives the amplitude-limited data signal and a delay-adjustment signal as input and provides a delayed amplitude-limited data signal as output. Both the rising edge phase detector (4) and the falling edge phase detector (5) take both the delayed amplitude-limited data signal and a clock signal as inputs, and provide a phase error signal derived from the rising and falling edges of the delayed amplitude-limited data signal respectively. The summer (7) receives the phase error signals as inputs and provides their sum as an output signal. The phase loop filter (8) may receive a mode signal along with the sum of the phase error signals as inputs, and provides the delay-adjustment signal (input by the adjustable delay) as output. The phase adjustment circuit (2) is described in detail below. The retiming circuit (3) may be implemented using a single D-type bistable (15) receiving the delayed amplitude-limited data signal on its input D15, a clock signal on input C15, and providing the retimed data signal on output Q15. The signal regenerator is adapted to receive a weak (including noisy and/or intermittent) electrical signal consisting of separated bursts of data, to amplify this and, using a clock input, to regenerate the data and output it. Control loops with switched time constants are used to learn the amplitude and phase of each burst of data. Transmitter and receiver are assumed to be synchronised. Each burst of data is encoded as a synchronisation part followed by a data part, illustrated in FIG. 2, which shows the end (51) of a data burst followed by the beginning (52, 53, 54) of a second burst. In the example shown, the first data burst is a stronger signal than is the second burst. The synchronisation part comprises a period of no signal (52) followed by a training period (53) comprising a bit pattern exhibiting a high occurrence of state changes, ideally containing a period in the form of a strictly alternating pattern of 1's and 0's. Where a pattern having a lower frequency of state changes is employed, the training pattern may have to be longer than that required in the ideal case. The data part of each burst (54, 51) may be of arbitrary length, though this may be constrained by the characteristics of the phase adjustment circuit as described in more detail below. A nominal threshold value as it might be set as the illustrated signal is received is shown as a dashed line (55). The threshold adjustment system operates in multiple modes. A "learn" mode is intended for use during receipt of the synchronisation part of each burst; a "slow" mode is intended for use during receipt of the data part of each burst. In "learn" mode a time-average of the signal received from the amplifier (11) is created by the threshold loop filter (13). The revised threshold signal is fed back to an input of the first amplifier (1). Where the signal contains a high frequency of rising and falling pulse edges (53), this feedback may bring the threshold (55) roughly to the correct value (i.e. the middle of the eye of the data signal) during receipt of, for example, a few tens of bits. This threshold acquisition process is started from the no-light side of the eye in order to achieve a quicker response where the signal strengths of successive bursts may vary widely. At data speeds of, for example, 6-10 Gbit/s, the threshold value may be determined within a few tens of nanoseconds. Once the approximate threshold value has been found during "learn" mode, the threshold adjustment subsystem switches, or is switched, to "slow" mode. In this mode, further adjustment to the threshold value is determined based upon threshold error signals received from the phase adjustment circuit. Alternatively, in "slow" mode, further adjustment to the threshold value may be determined using a time-average of the data stream, but with a time constant typically longer than that used in "learn" mode. The data part of each burst may contain information relating to changing the operating mode of the signal generator, and from which the mode input signals may be derived by means of a suitable feedback loop. For example, the data part may include, inter alia, a header identifying the beginning of the data part, the length of the data part, or a special bit pattern indicating the end of the data part. Such mode-related information may be extracted from the re-timed data signal and fed back to the mode inputs of the signal regenerator. Alternatively, the mode signals may be derived either locally or from information derived from a distinct signalling channel associated with the data signal. The mode input to the phase loop filter (8) may include modes to set the adjustable delay to an initial (typically mid-range) value, or to vary the filter characteristics (for example, the cut-off frequency). The range of modes may be either discrete or continuous according to the application. The decision threshold adjustment system can cope with very large changes in signal level. Where peak to peak wander and jitter in the data signal can be kept within known finite limits, and the phase adjustment subsystem (2) adapted accordingly, the receiver will also work with continuous data, for example SONET and SDH. The receiver may be used in a cell-based (for example ATM) switch to receive successive bursts of, for example, one or more ATM cells, each successive burst potentially coming from a distinct signal source and therefore potentially varying widely both in signal strength and in phase. A circuit diagram of a first embodiment of a phase detector (100) in accordance with the present invention is shown in FIG. 3, comprising: a data reduction circuit (101), a resynchronisation circuit (102), a first shift register circuit (103), a second shift register circuit (104), and first and second Exclusive OR (XOR) gates (105, 106). The data reduction circuit (101) takes as input a data signal. The resynchronisation circuit (102) takes as inputs the output from the data reduction circuit (101) and a clock signal. The first shift register circuit (103) takes as inputs the output from the resynchronisation circuit (102) and a clock signal phase-shifted by an amount A. The second shift register circuit (104) takes as inputs the output from the first shift register circuit (103) and a clock signal phase-shifted by an amount A+B. The first XOR gate (105) takes as inputs the output from the data reduction circuit (101) and the output from the first shift register circuit (103). The second XOR gate (106) takes as inputs the output from the resynchronisation circuit (102) and the output from the second shift register circuit (104). The data-reduction circuit (101) is operable to produce a reduced data digital output signal which changes state responsive only to the receipt of positive-going state changes or only to the receipt of negative going state changes in the data signal. This reduces the speed requirements of subsequent parts of the apparatus since the frequency of state changes in the output signal is at most half that of the received data signal. Where the output signal does not change state upon receipt of every positive-going or negative-going state change, the frequency of state changes in the output signal will be reduced still further. The resynchronisation circuit (102) is operable to receive a clock signal at a first input and, at a second input, an output from the data-reduction circuit and to provide a resynchronised reduced data signal. The first shift register circuit (103) is operable to receive a clock signal phase shifted by an amount A at a first input and, at a second input, an output from the second circuit and to provide a resynchronised reduced data signal delayed by an amount A. The second shift register circuit (104) is operable to receive a clock signal phase shifted by an amount A+B at a first input and, at a second input, an output from the third circuit (103) and to provide a resynchronised reduced data signal delayed by an amount A+B. The first XOR gate (105) is operable to generate a phase difference signal between the reduced data signal and the delayed resynchronised reduced data signal. The second XOR gate (106) is operable to generate a reference signal being the difference between the resynchronised reduced data signal and the resynchronised reduced data signal delayed an amount A+B. The difference between the phase difference signal and the reference signal varies linearly with the phase difference between the data signal and the clock signal. XOR gate (106) compares the edges of the signals output from the resynchronisation circuit (102) and the second shift register (104) respectively, to give a signal the duration of whose pulses is dependant only on the clock period. Pulse durations are as measured between the half-height points of the pulses. The frequency with which these pulses occur is dependent on the frequency of occurrence of rising edges in the data signal received by the data-reduction circuit (101). XOR gate (105) compares the edges of signals output from the data reduction circuit (101) and the first shift register (103) respectively, giving rise to a signal having pulse widths dependant both on the clock period and on the difference in phase between the clock signal and the data signal received by the data reduction circuit (101). The use of the shift register to phase-shift the signal to one of the inputs of XOR gate (105) by an amount A means that the pulses in the signal output from XOR gate (105) vary in duration from A to A+1 clock cycles. In existing detectors, pulse durations in the phase signal vary between 0 and 1 clock cycles but, where the pulse durations of the phase signal fall below 0.5 clock cycles, the pulse duration does not vary linearly with the phase difference. By extending each pulse by a known amount and thereby ensuring that no pulse in the phase signal is narrow enough to fall in the range where the non-linearity occurs, the present invention avoids that source of non-linearity. By comparing the pulse durations at the outputs of the two XOR gates (105, 106) it is possible to measure the phase difference between the clock signal and the data signal. This comparison may be done by integrating and subtracting the two signals to give a phase difference signal. A phase difference signal so generated varies linearly with the phase difference between clock and data. Use of such a phase difference signal may permit construction of simpler and faster control loop mechanisms for the purpose of adjusting the phase difference between the clock signal and the data signal. A circuit diagram of a further embodiment of a phase detector in accordance with the present invention is shown in FIG. 4, comprising: first and second D-Type bistables (201, 202), first and second Latches (203, 204), and first and second Exclusive OR gates (XOR gates) (105, 106). D- Type (201) implements the data reduction circuit (101) of the first embodiment, D-Type (202) implements the resynchronisation circuit (102), latch (203) implements the first shift register (103), and latch (204) implements the second shift register (104). D-Type (201) receives a data signal on input C201 and receives output from its own Q201 output on input D201. D-Type (202) receives, on input D202, the signal from output Q201 of D-Type (201), and receives a clock signal on input C201. Latch (203) receives, on input D203, the signal from output Q202 of D-type (202) and receives a clock signal on input C203. Latch (204) receives, on input D204, the signal from output Q3 of the first latch (203) and receives a clock signal on input C204. XOR gate (105) receives, as inputs, signals from output Q201 of D-Type (201) and output Q203 of latch (203) respectively. XOR gate (106) receives, as inputs, signals from output Q202 of D-Type (202) and output Q204 of latch (204) respectively. The output signal states of D-Type (201) change only on rising edges of the data signal arriving on input C201. Edges occur in the signal on output Q201 of D-Type (201) at a half the frequency of edges in the data signal (that is, the frequency of edges is reduced by a factor of two). D-Type (201) could also be arranged so that it changes state on the falling edges of the data signal. One means of achieving this is to invert the data signal before it arrives at D-Type (201). D-Type (201) would then operate upon rising edges in the inverted data signal. Rising edges in inverted data signal correspond to falling edges in the data signal and so the desired effect would be achieved. The D-Types employed in this embodiment are positive edge triggered. Each rising edge in the data signal therefore causes a change on the Q201 output signal of D-type (201) (the reduced data signal) with edge timing that depends on the data signal. This change propagates through D-type (202) and latches (203) and (204) with edge timing determined by the clock or clock. Hence the signal output from D-type (202) (the synchronised reduced data signal) is identical to that output from D-type (201) except in that the synchronised reduced data signal is further phase-shifted so as to bring it into synchronisation with the clock. The latches are transparent when the clock is high: output signals change state in response to changes in state in the D input signal only when the clock signal is high; when the clock signal is low, the output state remains unchanged. Each latch introduces a phase shift of 0.5 clock cycles. In this embodiment, pulses in the signal output by XOR gate (106) have a nominal duration of one clock period. Pulses output by XOR gate (105) vary in duration from 0.5 to 1.5 clock cycles. Advantageously, critical timing paths through the circuit exhibit similar propagation delays. This is achieved by ensuring that signals pass through the same number of bistable devices. The circuit is therefore largely insensitive to changes in the characteristics of the components so long as they all move together, as they would in an integrated circuit implementation. Using bistables or other components having characteristic properties similar to those required of latches in this construction in place of the latches would achieve a similar purpose, but at the possible cost of occupying a greater surface area in an integrated chip implementation. Similar replacement of the D-type bistables by circuits having the requisite characteristics would be evident to a person skilled in the art. Example signals at selected points in the circuit shown in FIG. 4 are shown in FIG. 5. The signals shown are (a) an example clock signal and (b) an example data signal, followed by (c) the Q201 output signal from D-Type (201), (d) the Q202 output of D-Type (202), (e) the Q3 output of latch (203), (f) the Q204 output of latch (204), (g) the phase signal output from XOR (105), and (h) the reference signal output from XOR (106). FIG. 5(i) shows the difference between the phase signal (FIG. 5(g)) output from the first XOR (105), and the reference signal (FIG. 5(h)) output from the second XOR (106). A further embodiment of a phase detector in accordance with the present invention, shown in FIG. 6, is similar to the second embodiment in FIG. 4, except in the implementation of the data-reduction circuit (101) and the first shift register (103). The data-reduction circuit in this embodiment comprises two D-types (301, 302); the first shift register comprises two latches (303, 304). D-type (301) receives a data signal on input C301 and the output from Q302 on input D301. D-type (302) receives the data signal on input C302 and the output from Q301 on input D302. A reduced data signal is output from Q302. Latch (303) receives a resynchronised reduced data signal on input D303 and a clock signal on input C303. Latch (304) receives output from Q303 on input D304, and a clock signal on input C304. Latch (204) receives on input D204 the output signal from Q304 and receives a clock signal on input C204. The synchronised reduced data signal output at Q304 is phase-shifted by one clock cycle with respect to the reduced data signal input at D303. The signal output at Q204 is further phase-shifted by 0.5 clock cycles. In this embodiment, pulses in the signal output by the XOR gate (106) have a nominal duration of 1.5 clock periods. Pulses output by XOR gate (105) vary in duration from 1.0 to 2.0 clock periods In this embodiment, the signal on the Q output of D-Type (302) changes state only on every second rising edge of the data signal (that is, the frequency of edges is reduced by a factor of four) and pulses in the signal representing the phase difference vary in duration between 1.0 and 2.0 clock periods. Example signals at selected points in the circuit shown in FIG. 6 are shown in FIG. 7. The signals shown are (a) an example clock signal and (b) an example data signal, followed in turn by the resultant output from (c) the Q output of D-Type (302), (d) the Q output of D-Type (202), (e) the Q output of latch (303), (f) the Q output of latch (304), (g) the Q output of latch (204), (h) the phase signal output from the first XOR (105), and (i) the reference signal output from the second XOR (106). FIG. 7(j) shows the difference between (h) the phase signal output from the first XOR (105), and (i) the reference signal output from the second XOR (106). It would be possible to further vary the range of the phase difference signal pulse durations by addition to the circuit of further D-types and latches in an obvious way. It is also possible to employ a poly-phase clock rather than a two-phase clock, and FIG. 8 shows a third embodiment of a phase detector as an example. The circuit of FIG. 8 employs a four-phase clock signal and outputs a phase signal having pulse durations in the range from 0.75 and 1.75 clock periods. In this embodiment, both shift registers (103, 104) in the first embodiment are implemented by D-types (401, 402). Furthermore, D-types (401) receives on input C401 a signal being the second phase of the clock, whilst the second replacement D-type (402) receives on input C402 a signal being the fourth phase of the clock. Example signals at selected points in the circuit shown in FIG. 8 are shown in FIG. 9. The signals shown are (a-d) example signals of representative phases of a four-phase clock and (e) an example data signal, (f) the resultant outputs from Q 201 of the first D-Type (201), (g) output Q 202 of D-Type (202), (h) outputs Q 401 of D-Type (401), (i) output Q 402 of D-Type (402), (j) the phase signal output from the first XOR (105), and (k) the reference signal output from the second XOR (106). FIG. 9(l) shows the difference between (j) the phase signal output from the first XOR (105), and (k) the reference signal output from the second XOR (106). As in the second embodiment, it would be possible to vary the range of the phase difference signal pulse durations by extension of the data-reduction circuit (101) and the first shift register (103). In a further embodiment of a phase detector, illustrated in FIG. 10, additional circuitry provides an integrated analogue output signal as the phase difference signal. In addition to the first embodiment of a phase detector (100), the circuitry comprises: three resistors (501, 502, 503), two capacitors (504, 505) and an amplifier (506). The phase detector (100) receives as inputs a data signal and one or more clock signals. The phase signal output from the phase detector (100) is provided as input to the first resistor (501), whilst the reference output signal from the phase detector (100) is provided as input to the second resistor (502). Output from the first resistor (501) is connected both to the positive input line of the amplifier (506) and to one side of the first capacitor (504); output from the second resistor (502) is connected both to the negative input line of the amplifier (506) and to the other side of the first capacitor (504). The remaining resistor (503) and capacitor (505) are connected in parallel between the output from the second resistor (502) and the output from the amplifier (506). The additional circuitry is provided both to subtract the reference signal from the phase signal and to smooth the resultant phase difference signal. The amplitude of the resulting integrated analogue signal is linearly related to the difference in phase between the data signal and the clock signal. The phase difference indicated by the circuit is dependent on the transition density of the incoming data signal, however the midpoint (the balanced condition where the reference signal is a time shifted version of the phase signal) is not affected. A phase detector can be provided, in a further embodiment, as part of a phase locked loop circuit as shown in FIG. 11, comprising a phase detector (601), a subtractor (602), a loop filter (603), an adjustable oscillator (604) (for example a voltage controlled oscillator), and a re-timing circuit (3). A data signal is provided as input both to the phase detector (601) and as the data input to the re-timing circuit (3). The phase signal and reference signal output from the phase detector (601) are provided as inputs to the subtractor (602). The output signal from the subtractor (602) is provided as input to the loop filter (603); output from the loop filter is provided as input to the adjustable oscillator (604). Output from the adjustable oscillator (604) is provided both to the clock input of the phase detector (601) and to the clock input of the re-timing circuit (3). The output signal from output Q 602 of D-Type (602) is a re-timed data signal. The subtractor (602) and loop filter (603) use the phase difference information provided from the phase detector output signals to vary the frequency of the clock signal generated by the adjustable oscillator so as to reduce the phase difference between the clock signal and the data signal. The D-type acts to regenerate the data signal retimed in synchronisation with the clock signal. In a still further embodiment, a phase detector is provided as part of a circuit to control data delay to re-time a data signal. An example of such a circuit is shown in FIG. 12, comprising: an adjustable delay (6) (for example, a voltage controlled delay), a re-timing circuit (3), a phase detector (601), a subtractor (602), and a loop filter (603). A free running clock signal is provided as input to both the phase detector (601) and as the clock input to re-timing circuit (3). In addition, a data signal output from the adjustable delay (6) is provided as input both to the phase detector (601) and to the data input of re-timing circuit (3). The phase signal and reference signal output from the phase detector (601) are provided as inputs to the subtractor (602). The output signal from the subtractor (602) is provided as input to the loop filter (603); output from the loop filter is provided as input to the adjustable data delay (6), which also receives a data signal as input. The signal output from re-timing circuit (3) is the re-timed data signal. The subtractor (602) and loop filter (603) use the phase difference information provided from the phase detector output signals to vary the length of delay introduced in the data signal path so as to reduce the phase difference between the clock signal and the data signal. The re-timing circuit (3) acts to regenerate the data signal retimed in synchronisation with the clock signal. In a still further embodiment, in which the data signal is itself a clock signal, the detector in all its embodiments may be employed as a clock-to-clock phase detector, provided that the data-reduction factor exceeds two. Ideally, threshold values and clock phase are set such that, when applied to a received data signal, they coincide exactly with the actual phase and threshold characteristics of the data signal. An example of this situation is shown in FIG. 13. The threshold value (shown as a horizontal dashed line) is set at half the amplitude of the data signal, and the clock phases (shown as vertical dashed lines) occur perfectly in synchronisation with the points at which the data signal crosses the threshold value. In practice, however, it is likely that either the threshold value is set too high or too low (a threshold error) or that the data arrives out of phase with the clock pulses (a phase error), or both (a compound phase/threshold error). A threshold error is characterised in that either (a) rising edges of the data signal are detected to arrive late and falling edges to arrive early with respect to the clock pulses or (b) rising edges of the data signal are detected to arrive early and falling edges to arrive late with respect to the clock pulses. The former case indicates that the threshold has been set too high; the latter case indicates that the threshold has been set too low. A phase error is characterised in that either (a) both rising edges and falling edges of the data signal are detected to arrive late with respect to the clock pulses or (b) both rising edges and falling edges of the data signal are detected to arrive early with respect to the clock pulses. The former case indicates that the data signal is late with respect to the clock; the latter case indicates that the data signal is early with respect to the clock. A compound phase/threshold error is characterised in that whilst both rising edges and falling edges are either both late or both early, the degree of late or early arrival of rising edges differs from that of falling edges. By way of example, FIGS. 13-16 illustrate four cases: the ideal case of neither phase nor threshold error; threshold error but no phase error; phase error but no threshold error; and both threshold error and phase error. FIG. 13 shows an incoming data signal (63), the re-timing clock (64), the threshold (61) and the ideal positions for the data transitions (62). The data signal is sliced at the threshold and the resultant signal is shown (65). In this case the incoming data (63) is ideally placed with respect to the threshold (61) and ideal transition positions (62) and the sliced data (65) is a faithful copy of the original. FIG. 14 shows an incoming data signal (73), the re-timing clock (74), the threshold (71) and the ideal positions for the data transitions (72). The data signal is sliced at the threshold and the resultant data signal is shown (75). In this case the threshold for the incoming data (71) is too high although the transitions are correctly positioned. The sliced data signal (75) now has late rising edges (76) and early falling edges (77) characteristic of a high threshold value (threshold error). FIG. 15 shows an incoming data signal (83), the re-timing clock (84), the threshold (81) and the ideal positions for the data transitions (82). The data signal is sliced at the threshold and the resultant data signal is shown (85). In this case the data signal is late with respect to ideal transition positions (82) although the threshold is correctly positioned. The sliced data signal (85) now has late rising edges (86) and late falling edges (87) characteristic of a late data signal (phase error). FIG. 16 shows an incoming data signal (93), the re-timing clock (94), the threshold (91) and the ideal positions for the data transitions (92). The data signal is sliced at the threshold and the resultant data signal is shown (95). In this case the data signal is late with respect to ideal transition positions (92) and the threshold is too high. The sliced data signal (95) now has very late rising edges (96) and late falling edges (97) characteristic of both a late data signal (phase error) and a high threshold. A block circuit diagram for a first embodiment of a threshold detector in accordance with the present invention is shown in FIG. 17. This first embodiment comprises: a rising/falling phase detector (751), a subtractor (752), and a loop filter (753). Together, the subtractor (752) and the loop filter (753) constitute an example of a threshold differencer (754). The threshold differencer (754) may be implemented by alternative means which achieve the same net effect. The rising/falling phase detector (751) has both a clock signal and a data signal as inputs, and has distinct phase difference signals as outputs. Each phase difference signal represents a difference in phase between the clock signal and the data signal: the first phase difference signal is derived from the timing of the rising edges of the data signal and varies with the phase difference between the clock and the rising edges of the data signal; the second phase difference signal is derived from the timing of the falling edges of the data signal and varies with the phase difference between the clock and the falling edges of the data signal. In a preferred embodiment, such a rising/falling phase detector (751) may be constructed using a rising edge phase detector (4) in parallel with a falling edge phase detector (5) as shown in FIG. 17. Each component phase detector takes as input both the data signal and the clock signal received by the rising/falling phase detector and outputs a single phase difference signal. The phase detectors differ in that the rising edge phase detector (4) outputs a signal which varies linearly with the phase difference between the clock and the rising edges of the data signal; the falling edge phase detector is derived from the timing of the falling edges of the data signal and varies linearly with the phase difference between the clock and the falling edges of the data signal. As a consequence of the difference in their operation, the component phase detectors need not generate identical phase difference signals even when they each receive the same data signal, for example when the data mark-space ratio is not 1:1. The subtractor (752) receives as inputs the phase difference signals from the rising/falling phase detector (751) and outputs a signal which represents the difference between the received phase difference signals. The loop filter (753) receives as input the signal output from the subtractor (752) and outputs a signal which varies with the difference between the threshold value used in generating the received data signal and the true value of that signal's threshold. In embodiments in which the outputs from the rising/falling phase detector (751) vary linearly with the phase differences between the data signal and the clock signal, the loop filter output varies linearly with the difference between the threshold value used in generating the received data signal and the true value of that signal's threshold. A block circuit diagram for a second embodiment in accordance with the present invention is shown in FIG. 18. This embodiment comprises: a rising/falling phase detector (751), a summer (7), a loop filter (8), and a threshold differencer (754). The summer (7) and the loop filter (8) constitute an example of a phase differencer (9). This embodiment differs from the first embodiment in that the phase differencer (9) is added to the circuit: the summer (7) receives as inputs the phase difference signals from the rising/falling phase detector (1) and outputs a signal which represents the sum of the received phase difference signals; the loop filter (8) receives as input the signal output from the summer (7) and in turn outputs a signal, which varies linearly with the difference between the phase of the data signal and the phase of the clock. This embodiment differs from the first embodiment in that, in addition to providing an output signal which varies linearly with the difference between the threshold value used in generating the received data signal and the true value of that signal's threshold, it also provides a phase difference signal which (a) varies linearly with the difference between the phase of the data signal and the phase of the clock signal and (b) is derived from information derived both from rising edges and from falling edges of the data signal. Current practice employs separate detector circuitry to extract phase information and threshold information. Common use of one or more components by both detector circuits would give a reduction both in silicon used and power required. In this embodiment, shared use is made of a rising/falling phase detector to generate signals both for threshold difference and for phase difference, thereby minimising the overall circuitry required. In this way both threshold and phase error signals are derived from measurement of a single characteristic of the received data signal: namely measurement of the times at which the transition edges of the received data signal passes a given threshold voltage. A block circuit diagram for a third embodiment of a threshold detector in accordance with the present invention is shown in FIG. 19. This first embodiment comprises: a rising/falling phase detector (751), a threshold differencer (754), and an amplifier (10). This embodiment differs from the first embodiment in that an amplifier is added to complete a feedback circuit: the rising/falling phase detector (751) receives as input both the clock signal and the signal (the data-out signal) output from the amplifier (10); the amplifier (10) receives as input both the data signal and the output signal from the threshold differencer (754). This embodiment provides a means for threshold tracking and feedback, the output from the threshold differencer (754) being employed to adjust the mark-space ratio of the data-out signal output from the amplifier (10). A block circuit diagram for a fourth embodiment of a threshold detector in accordance with the present invention is shown in FIG. 20. This first embodiment comprises: a rising/falling phase detector (1), a threshold differencer (754), an amplifier (10), a phase differencer (9), an adjustable delay (6), and a re-timing circuit (3). This embodiment differs from the third embodiment in that the phase differencer (9), the adjustable delay (6), and the re-timing circuit (3) are added. The phase differencer (9) takes as inputs the output phase difference signals from the rising/falling phase detector (751). The adjustable delay (6) is located between the amplifier (10) and the rising/falling phase detector (751), taking both the output signal from the amplifier (10) and the output signal from the phase differencer (9) as its. The rising/falling phase detector (751) takes the output from the adjustable delay (6) as input on its data line. The re-timing circuit (3) takes as inputs the delayed data signal output from the adjustable delay (6) and the clock signal, and outputs a re-timed data signal. The phase difference signal output from the phase differencer (9) is utilised to provide feedback to the adjustable delay (6) so as to vary the phase difference between the signal received on the data line of the rising/falling phase detector and the clock signal. In this embodiment, common use is made of a rising/falling phase detector to derive signals both for threshold difference and for phase difference, thereby minimising the overall circuitry required. Further embodiments of the present invention may be derived by locating the adjustable delay (6) in the clock signal path rather than in the data signal path or by locating an adjustable delay in both of those paths separately or by means of adjusting the clock signal by other means (for example, by means of a voltage controlled oscillator), together with appropriately modified circuitry providing feedback from the rising/falling phase detector. Other variations within the scope of the following claims will be apparent to a skilled person.	The invention seeks to provide an improved, bandwidth-efficient method and apparatus for acquiring and tracking bursts of data, or continuous data, of varying and unpredictable amplitude, extinction ratio, and phase. The system avoids the use of digital signal processing which is not practical at high data signal rates. The system also obviates encoding of the data signal using a line code, thereby extending the existing technology to give a significant increase in data throughput for the same available bandwidth. The system may treat acquisition of each data burst, comprising alternate synchronisation parts and data parts, ab initio.	7
CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit under 35 U.S.C. §119(e) of the following U.S. provisional patent application, which is incorporated by reference herein: U.S. Provisional Patent Application No. 60/806,032, filed Jun. 28, 2006, and entitled “PLASMA SURFACE TREATMENT OF COMPOSITES FOR BONDING”, by Robert Hicks et al. STATEMENT OF GOVERNMENT RIGHTS This invention was made with Government support under contract No. FA8650-05-C-5602 awarded by the United States Air Force. The Government has certain rights in this invention. BACKGROUND OF THE INVENTION 1. Field of the Invention The invention is related to a method of bonding composite structures together by means of treating the composite surfaces with an atmospheric plasma, followed by applying adhesive to one of the surfaces, joining the composites together, and curing said adhesive. 2. Description of the Related Art Composite materials are used in the aerospace, automotive, electronics, medical and sports equipment industries because of their unique properties (M. M. Schwartz, “Post Processing of Composites,” Society for the Advancement of Materials and Process Engineering , Covina, Calif. 1996). They are lightweight, exceptionally strong, chemically and thermally stable, and can be processed into a wide variety of shapes. Their high strength to weight ratio makes them especially attractive for use in aircraft, where by replacing the metal structures, they can reduce the weight of the vehicle and dramatically save on fuel costs. A composite is composed of a reinforcement and a matrix material (M. M. Schwartz, ibid.). The reinforcement may be fibers, whiskers, platelets, flakes, and other shapes. Fibers are the most common, and among these glass, graphite and aramid fibers are widely used. Matrix materials may be thermosetting or thermoplastic polymers, metals, or ceramics. Polymers are attractive because they are strong and lightweight, thermally and chemically stable, and are conveniently processed into desired structures. Thermosetting resins react at elevated temperature to produce three dimensional crosslinked networks. Once reacted, thermosets remain fixed in shape, and cannot be reprocessed. Thermosets comprise polyesters, epoxy resins, phenolic resins, bismaleimides and polyimides. Thermoplastics are polymers that do not chemically react when heated. Instead they may be melted and formed into engineered structures, and can be reprocessed if desired. They offer the potential of being tougher and more stable than thermosets. Examples of thermoplastic matrix materials include, but are not limited to, polyethersulfone (PES), polyetherimide (PEI), polyether-etherketone (PEEK), and polyetherketoneketone (PEKK). Carbon-fiber-reinforced PEEK is an especially attractive composite. PEEK is an aromatic polymer that has excellent mechanical strength, and high resistance to fatigue, impact and abrasion. It is also fire resistant and a good electrical insulator (J. Jang and H. Kim, Polymer Composites , Vol. 18, p. 125 (1997); and M. M. Schwartz, ibid.). In the medical industry, PEEK is an attractive material for implants due to its biocompatibility. In the aerospace and automotive industries, metal structures are being replaced by carbon-fiber-reinforced PEEK, because of its superior mechanical properties and high strength-to-weight ratio. Although carbon-fiber-reinforced composites have attractive properties for use in many engineered products, they suffer from a major drawback in that these materials often do not adhere well to other surfaces. Without specialized surface treatments, composites may not form strong bonds to epoxy resins (Schwartz, ibid.). This is especially true of thermoplastics, such as PES, PEI, PEEK and PEKK. Adhesives and surface preparation methods designed for other composites do not provide sufficiently strong bonds, so that under a relatively low shearing force they undergo adhesive failure with the glue separating cleanly from the polymer surface. Therefore to use these materials in aircraft and other structures, the thermoplastic composites must be bolted together. This approach produces a weaker structure, and increases the total weight of the aircraft. Many methods have been examined for treating polymer composites prior to adhesive bonding. These include bead blasting, wet chemical etching, flame oxidation, UV/ozone treatment, argon ion bombardment, and oxygen plasma etching (M. M. Schwartz, ibid.). Among these methods, oxygen plasma treatment has been found to be the most effective at increasing the bond strength of epoxy adhesives to thermosetting and thermoplastic composites. N. Inagaki and coworkers, (“Surface modification of poly (aryl ether ether ketone) film by remote oxygen plasma,” Journal of Applied Polymer Science , Vol. 68, p. 271 (1998)) describe the treatment of PEEK with a low-pressure oxygen plasma operated at 0.13 Pascal. After exposing the PEEK film for 30 s, the water contact angle dropped from 93 to about 60 degrees. J. Comyn, et al. (“Corona discharge treatment of polyetheretherketone (PEEK) for adhesive bonding,” Intl. Journal of Adhesion and Adhesives , Vol. 16, p. 97 (1996)) subjected PEEK film to an oxygen plasma for 60 s at 40 Pascal. These authors observed a decrease in the water contact angle. After bonding samples together with epoxy adhesive, they found that the plasma treatment yielded a large increase in peel strength and a doubling of the lap shear strength over untreated samples. One of the disadvantages of oxygen plasmas used in the prior art is that they were generated in a vacuum (M. M. Schwartz, ibid.). To receive treatment the composite parts must be inserted into a sealed chamber and the gas pumped away prior to striking the discharge. This approach limits the size and shape of parts that can be treated, since they must fit inside the chamber. Moreover, vacuum operation requires expensive equipment that must be maintained, is more time consuming, and more expensive than atmospheric pressure processes. The use of atmospheric pressure plasmas to treat polymer composites has been described in the prior art. In particular, coronas and dielectric barrier discharges have been used to treat polymers for increased wettability and surface adhesion (see for example, P. J. Ricatto, et al., “Chemical processing using non-thermal discharge plasma,” U.S. Pat. No. 6,923,890, Aug. 2, 2005; L. A. Rosenthal and D. A Davis, “Electrical Characterization of a Corona Discharge for Surface Treatment,” IEEE Transaction on Industry Applications, Vol. 1A-11, p. 328 (1975); and J. Comyn, et al., “Corona-discharge treatment of polyether-etherketone (PEEK) for adhesive bonding,” Intl. Journal of Adhesion and Adhesives , Vol. 16, p. 301 (1996)). The latter authors showed an approximate doubling of the lap shear strength following corona treatment, similar to what was achieved with the vacuum oxygen plasma. Nevertheless, the dielectric barrier discharge and the corona generate the atmospheric pressure plasma between two closely spaced electrodes separated by a dielectric spacer. In order to treat the composite, it must be in the form of a flexible film less than 1.0 mm thick, so that it can be fed between the two electrodes. This design severely restricts the type of composite materials that can be treated, and is not applicable to composites that have been formed into rigid three-dimensional shapes, such as those used in the structure of an aircraft. Therefore, there is a need for a method of adhesively bonding a composite work piece of any size and shape that utilizes an effective surface treatment of the material, so that when the part is joined with another work piece, they form a strong, permanent bond. In particular, there is a need for a method of adhesively bonding a composite work piece where an atmospheric pressure plasma is used for surface treatment, such that the plasma can be conveniently applied to the surface of any composite structure, regardless of its size and shape, and after treatment and application of the adhesive a strong, permanent bond is obtained. As described hereafter, these and other needs are met by embodiments of the present invention. SUMMARY OF THE INVENTION To overcome the limitations in the prior art described above, a method for bonding composites together that is fast and effective, and can be applied to any structure regardless of its size and shape, and its related product are disclosed. The method comprises first subjecting at least a part of a composite work piece to a low-temperature, atmospheric pressure plasma, wherein the reactive gas from the plasma flows out of the device and onto the surface of the composite work piece, then applying an adhesive to the surface of the treated composite work piece, and joining the composite work piece together with a second work piece. The adhesive may be cured such that it forms a strong, permanent bond. The method further comprises using an atmospheric pressure plasma to treat at least a part of the surfaces of the composite work piece, thereby activating the surface for adhesive bonding, wherein the atmospheric pressure plasma is generated in a atmospheric plasma delivery device that can be translated over a composite surface by hand or with a robot. The method further comprises using a self-contained atmospheric pressure plasma delivery device to treat a composite surface thereby activating it for adhesive bonding, wherein said plasma device is portable, and can be moved to a location that is convenient for treating the composites structure. A typical embodiment of the invention comprises a method of bonding a composite, including the steps of exposing a surface of a composite work piece to a reactive gas beam from an atmospheric pressure plasma delivery device, applying adhesive to at least portion of the surface after exposure to the reactive gas beam, and joining the composite work piece to a second work piece with the applied adhesive. The atmospheric pressure plasma delivery device projects the reactive gas beam exterior to the atmospheric pressure plasma delivery device from a head. The projected reactive gas beam may comprise a reactive oxygen species. The head of the atmospheric pressure plasma delivery device can disperse the reactive gas beam through a plurality of holes. Typically, the atmospheric pressure plasma delivery device generates the reactive gas beam by application of radio-frequency power across at least a pair of electrodes with a gas flowing between the pair of electrodes to become the reactive gas beam. For example, the radio frequency power may be at least 50 W applied at a frequency selected from the group consisting of approximately 13.56 MHz and 27.12 MHz. The atmospheric pressure plasma delivery device may be a self-contained that projects the reactive gas beam into an ambient atmospheric pressure environment. The head of the atmospheric pressure plasma delivery device may be maneuverable so that the reactive gas beam may be directed where desired. For example, the head of the atmospheric pressure plasma delivery device may be translated over the composite work piece at a rate from 0.5 inches per minute to 1.0 foot per second to expose the surface to the reactive gas beam. In some embodiments, the head of the atmospheric pressure plasma delivery device is translated over the composite work piece by hand. Alternately, the head of the atmospheric pressure plasma delivery device may be translated over the composite work piece by a robotic arm. Further, the composite work piece may comprise an aerospace structure. Particularly, at least one of the composite work piece and the second work piece comprises a damaged component of the aerospace structure. In further embodiments, a second surface of the second work piece may be exposed to the projected reactive gas beam from the atmospheric pressure plasma delivery device before joining the composite work piece and the second work piece. In addition, the adhesive may be cured to form a strong bond between the composite work piece and the second work piece. Curing the adhesive may comprises applying an elevated temperature environment for a sufficient time. In addition, the surface of the composite work piece may be cleaned with an organic solvent and drying prior to exposure with the reactive gas beam. Typically, at least one of the composite work piece and the second work piece comprises a polymer selected from the group consisting of polyester, phenolic resin, bismaleimide, polyimide, polyethersulfone, polyetherimide, polyetheretherketone, polyetherketoneketone, and a fiber reinforcement selected from the group consisting of carbon fibers and glass fibers. However, the second work piece may be a second material selected from the group consisting of a composite (e.g. any of the foregoing composite materials), a metal, and a ceramic. Another embodiment of the invention comprises a composite assembly, produced with a bonding process by the steps of exposing a surface of a composite work piece to a reactive gas beam from an atmospheric pressure plasma delivery device, applying adhesive to at least portion of the surface after exposure to the reactive gas beam, and joining the composite work piece to a second work piece with the applied adhesive. Here also, the atmospheric pressure plasma delivery device projects the reactive gas beam exterior to the atmospheric pressure plasma delivery device from a head. Typically, a bond between the composite work piece and the second work piece comprises a bond strength determined by cohesive failure. The composite assembly may be an aerospace structure assembled in an ambient environment and in some cases at least one of the composite work piece and the second work piece comprises a damaged component of the aerospace structure. In addition, the bonding process may also include exposing a second surface of the second work piece to the projected reactive gas beam from the atmospheric pressure plasma delivery device before joining the composite work piece and the second work piece. Further, the bonding process may include curing the adhesive to form a strong bond between the composite work piece and the second work piece. BRIEF DESCRIPTION OF THE DRAWINGS Referring now to the drawings in which like reference numbers represent corresponding parts throughout: FIG. 1 is a schematic of an apparatus that may be used to perform an exemplary embodiment of the present invention; FIG. 2 is a schematic of an exemplary embodiment of the invention being applied to the assembly or repair of an aircraft; and FIG. 3 is a block diagram of an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In the following description of the preferred embodiment, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration the specific embodiment in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural and functional changes may be made without departing from the scope of the present invention. A method of bonding composites to each other and to other materials utilizing a self-contained, atmospheric pressure plasma device, in which the steps comprise treating the surface of at least one composite with the atmospheric plasma for a time sufficient to activate said surface, applying adhesive to one of the surfaces, joining the materials together, and curing the adhesive. The method of bonding composites together may be applied to aerospace (e.g., aircraft) and other transportation vehicles, where at least one composite surface is treated with a self-contained atmospheric pressure plasma, adhesive is applied to said treated surface, the composite is joined to another composite or other material, and the adhesive is cured to form a strong, permanent bond. The many advantages and novel features that characterize embodiments of the invention are described in the matter presented below. Reference should be made to the drawings and figures, and to the accompanying descriptive matter, in which are illustrated exemplary embodiments of the present invention. Apparatus for Treating Composite Surfaces for Bonding An apparatus that may be used to practice an exemplary embodiment of the invention is illustrated in FIG. 1 . The apparatus comprise a handheld or robot-held plasma device ( 1 ) that is connected to an electrical power supply ( 2 ), a means of supplying a gas flow ( 3 ) to the plasma device ( 1 ), and a means of translating ( 4 ) the composite substrate ( 5 ) underneath the reactive gas beam ( 6 ) generated by the plasma device ( 1 ). In FIG. 1 , the power supply ( 2 ) is connected to an impedance matching network ( 7 ) so that the high-frequency power is properly coupled to the plasma device ( 1 ). Other power supply configurations may be used as will be understood by those skilled in the art. One example apparatus suitable for implementing embodiments of the invention is described in “Atmospheric Plasma Treatment of Polyetherethereketone Composites for Improved Adhesion,” by Hicks et al., SAMPE Fall Technical Conference Proceedings: Global Advances in Materials and Process Engineering, Dallas, Tex., Nov. 6-9, 2006, CD-ROM, pp. 9, which is incorporated by reference herein. Other atmospheric pressure plasma delivery device may also be used provided that they project a suitable atmospheric plasma from a head that can be manipulated over a work piece. Embodiments of the present invention are produced with an atmospheric pressure plasma delivery device ( 1 ) that projects the reactive gas beam ( 6 ) exterior to the device to from a head. The projected reactive gas beam and atmospheric plasma allow the application to composite work piece without the need of a vacuum chamber and on composite work piece that need not be small enough to pass through an fixed electrode gap as with the prior art. The head of the device ( 1 ) may comprise a plurality of holes to disperse the reactive gas beam ( 6 ), e.g. similar to a showerhead. Ideally, the device ( 1 ) may be portable and self-contain so that it can be easily manipulated to and used on a larger composite structure. Gas and power may be located remotely and coupled to the device ( 1 ) via flexible tubing and cables allowing the device ( 1 ) to be easily manipulated over the surface of the composite work piece ( 5 ). The gas supplied to the plasma device ( 1 ) may include, but is not limited to, air, oxygen, carbon dioxide, a gas molecule containing one or more oxygen atoms, hydrogen, nitrogen, carbon tetrafluoride, sulfur hexafluoride, argon, helium, and mixtures thereof. Particularly effective gases are air, oxygen, air mixed with argon or helium, and oxygen mixed with argon or helium, such as an approximately 0.1 vol. % to 2 vol. % mixture of either oxygen or air in argon or helium at a total flow rate of approximately 30.0 L/min for the argon or helium. The apparatus is operated by flowing gas through the plasma device ( 1 ), and applying an electrical signal from the power supply ( 2 ) and matching network ( 7 ) to electrodes located in said device, such that the gas breaks down and becomes at least partially ionized. One or more composite work pieces ( 5 ) are then translated underneath the reactive gas beam ( 6 ) using a means for translation ( 4 ) for a period of time sufficient to activate their surfaces for bonding. Alternatively, one may hold the composite work piece ( 5 ) stationary and translate the plasma device ( 1 ) and reactive gas beam ( 6 ) over the surface. Following surface treatment, adhesive is applied to one of the surfaces of the composites, the composites are joined together, and the adhesive is cured to form a strong, permanent bond. Embodiments of the invention are further illustrated in the examples described hereafter. Method for Bonding Composites Example 1 Carbon-fiber-reinforced polyetheretherketone was obtained in order to demonstrate the improved method of bonding composites together. The PEEK composite included 0° laminates, containing 16 plies that were fabricated from unidirectional prepreg using IM7 or AS4 carbon fibers. The PEEK panels were cut into 1.0″ by 6.0″ strips. After plasma surface treatment, an epoxy film adhesive, 3M Scotch-Weld™ AF-563M, was used to bond the composites together. The film adhesive was 0.06 wt. and 10 mils thick. The atmospheric pressure plasma device used to treat the PEEK contained a control unit that integrated together a radio frequency power supply operating at 13.56 MHz, a matching network, and a gas manifold with mass flow controllers that provided a mixture of 1.5 vol. % oxygen in helium at a flow rate of 30 L/min. The gas flow was directed through a cylindrical plasma device that was about 1.0 inch in diameter by 6.0 inches long. The device was configured with a gas inlet and a gas outlet that had many small holes creating a showerhead. In addition, the device contained electrodes connected to a radio frequency (RF) power supply that came into contact with the gas flowing through the device. Application of 100 W of RF power at 13.56 MHz to the device caused the gas to break down and form the low-temperature, atmospheric pressure plasma. Reactive species generated in the plasma flowed out through the showerhead and contacted PEEK composites that were placed a few millimeters downstream. The 1.0″ by 6.0″ strips of PEEK were treated with the atmospheric pressure plasma for a specified period of time. The film adhesive was applied to all but one inch of a given sample's length. Then two samples were joined and cured as follows: The specimen was clamped at ˜30 psig, and placed in an evacuated oven for 20 min. After the vacuum was released, the oven was ramped at a rate of 5° F./min to 275° F., and held at 275° F. for 1.5 hr. Next, the samples were cooled back to room temperature, and then force apart with a wedge to examine the failure mechanism of the adhesive bond. The results of the wedge test are shown in Table 1. Composite samples that were only cleaned with methanol (run 1) exhibited adhesive failure, in which the epoxy glue sheared cleanly off of one of the surfaces of the PEEK specimens. By contrast, samples treated with the plasma at a distance of 2.0 mm and 100 W RF power (runs 4 and 5) exhibited 96 to 100° A cohesive failure for treatment times of 20.0 s per inch 2 . Cohesive failure is characterized by shear occurring inside the cured epoxy such that a continuous film of glue remains adhered on both surfaces of the composite samples. TABLE 1 Test conditions for the 0° PEEK and 3M AF 563M adhesive. Run # Distance (mm) Power (W) Time (s/in 2 ) Results 1 Methanol clean (control) 0% cohesive failure 2 2.0 100 10 25% cohesive failure 3 2.0 100 15 90% cohesive failure 4 2.0 100 20 100% cohesive failure 5* 2.0 100 20 96% cohesive failure 6 5.0 100 20 20% cohesive failure 7 5.0 100 40 90% cohesive failure 8 5.0 100 60 80% cohesive failure 9 5.0 100 90 100% cohesive failure 10 10.0 100 20 0% cohesive failure 11 10.0 100 40 25% cohesive failure 12 10.0 100 60 30% cohesive failure 13 10.0 100 90 60% cohesive failure 14** 2.0 125 7 100% cohesive failure Waited 24 hours after plasma treatment before applying adhesive and curing. *Argon and 1.2 Torr oxygen used instead of helium and 11.4 Torr oxygen. The results presented in Table 1 show that longer treatment times are required to achieve cohesive failure if the plasma device is held further from the composite surface during treatment. For example, in run 9, 90.0 s per inch 2 of plasma treatment was needed to achieve 100% cohesive failure at a separation distance of 5.0 mm. This is most likely associated with a decline in the density of radical species in the plasma beam with distance from the device. In run 14, argon was fed to the plasma device instead of helium, and it was observed that only 7.0 s per inch 2 was needed to yield 100% cohesive failure of the bond. In this experiment, the distance between the plasma device and the sample was 2.0 mm, the RF power was 125 W, and the oxygen pressure was 1.2 Torr. The treatment time with the reactive gas depends on the design of the plasma device and the conditions used to operate it. For example, a rectangular plasma device was used to treat PEEK that produced a plasma beam 2.0 inches in length by 1/16 inch in width. The device was operated at 30.0 L/min of helium flow, 1.5 L/min of oxygen flow, 225 W at 27.12 MHz, and a distance between the device and the sample of 1.0 cm. The plasma device was translated over two 1.0″ by 7.0″ strips of carbon-fiber-reinforced PEEK placed side by side at a rate of 5.0 s per inch. After treatment, 3M AF563 film adhesive was applied to one of the strips, the two samples were joined together, and the adhesive cured as described above. Once the samples had cooled back to room temperature, the two strips were forced apart with a wedge. Examination of the samples revealed that failure was 100% cohesive with a continuous film of epoxy remaining on both surfaces. Example 2 Mechanical strength tests were performed on adhesively bonded strips of carbon-fiber-reinforced PEEK composites following the ASTM D1002 single-lap shear method and the ASTM D3165 double-notch lap shear method. For the ASTM D1002 test, PEEK panels, 6.0″ by 7.0″ were exposed to the plasma at 2.0 mm distance, using 100 W RF power, a mixture of 1.5 vol. % oxygen in helium at a flow rate of 30 L/min, and a treatment time of 30 s per inch 2 . After treatment, 3M Scotch-Weld™ AF-563 film adhesive was applied to the end of a panel to yield a 0.6 inch overlap between the adherends. The adhesive was cured following the same procedure described in Example 1 above. After curing, the 6.0″ by 7.0″ panels were cut into 1″ wide strips and then pulled apart using an Instron machine that recorded the force required to shear the bond. It was found that the samples treated with the atmospheric pressure oxygen and helium plasma for 30 s/in 2 exhibited lap shear strengths of 6300±100 psi. This value is comparable to the maximum strength of the adhesive reported by the manufacturer, 3M. By contrast, PEEK samples that were cleaned with methylethylketone prior to bonding together with the epoxy yielded lap shear strengths of 3500±600 psi. The double-notch lap shear tests, ASTM D3165, were performed with carbon-fiber-reinforced PEEK panels cut into 7.0″×6.0″ rectangles. The panels were wiped with isopropyl alcohol and subjected to 30 s of plasma treatment at the standard process conditions, i.e., 2 mm between the device and the sample, 100 W RF power, and a treatment time of 30 s/in 2 . After surface treatment, the 3M AF563M adhesive was applied to one panel and a second panel was placed on top. This sandwich structure was evacuated under a plastic covering, then inserted into an autoclave and pressurized from the top to 35 psig. Next, the temperature was ramped up at 5° F./min to 275° F. and held constant at 275° F. for 90 min. Each panel was cut into 1.0″×7.0″ strips, notched on both sides to yield a 1.0″ overlap region, and then tested on the Instron. Applying adhesive to PEEK that had been cleaned with isopropyl alcohol led to a shear strength of only 900±100 psi, and this specimen failed adhesively with the epoxy shearing off at one of the PEEK surfaces. By comparison, the samples treated with the atmospheric pressure plasma exhibited lap shear strengths of 5000±300 psi, and failed by a 100% cohesive mechanism. The plasma treatment time needed to achieve high lap shear strength depends on the atmospheric pressure plasma device used and the process conditions. For example, the cylindrical plasma device, 1.0 in in diameter by 6.0 in. long, was operated at 30.0 L/min of helium flow, 1.5 L/min of oxygen flow, 180 W at 27.12 MHz, and a distance between the device and the sample of 1.0 cm. After treating each 7.0″ by 6.0″ PEEK panel with the plasma for 15 s per inch 2 , the panels were bonded together with AF563 adhesive, cured as described above, cut into 1.0″ by 7.0″ strips, notched on both sides to provide a 1.0″ overlap region, and sheared apart in the Instron. The lap shear strength measured in this test was 5700±340 psi. Method of Bonding Composites on Aircraft Shown in FIG. 2 is an illustration of an exemplary embodiment of the present invention applied to the bonding of composites on aircraft, such as may be applied to any composite aerospace structure. For example, this could be performed where the wing struts are joined to the main body of the aircraft ( 10 ). An expanded view of the bonding operation is shown in FIG. 2 . A composite part ( 12 ) is to be joined to another aircraft part ( 11 ). Part ( 12 ) is being treated with a self-contained atmospheric pressure plasma device ( 13 ) that is mounted on a robot arm ( 16 ). An oxygen-containing gas is supplied to the plasma device ( 13 ) through the flexible feed line ( 15 ). Electrical power is applied to the plasma device sufficient to break down the gas and at least partially ionize it using the electrical cable ( 14 ). The reactive gas beam ( 17 ) generated by the plasma contacts the surface of the composite part ( 12 ) projected from the head of the device ( 13 ) as shown. By using the robot arm ( 16 ) to sweep the reactive gas beam over the surface of the composite part ( 12 ), a region of the surface ( 18 ) becomes activated for adhesive bonding. The next step may be to treat the other aircraft part ( 11 ) with the plasma device ( 13 ), although this step is not essential to carrying out this embodiment of the invention. After plasma treatment, adhesive would be applied to the activated surface ( 18 ) of the composite part ( 12 ). Then the aircraft parts ( 11 ) and ( 12 ) would be joined together and the adhesive cured following procedures that would be obvious to those skilled in the art. Process Chart FIG. 3 is a flowchart illustrating the steps used in practicing the present invention. Block 100 illustrates the step of providing a surface treatment to at least one composite work piece surface utilizing an atmospheric pressure plasma device. A reactive gas beam is projected from the head of the atmospheric pressure plasma device. The device may be portable and self-contained such that it can be employed on large structures (e.g., aerospace structures) that cannot be easily manipulate and/or may not fit within a chamber. Prior to step 100 , one may clean the surface with a suitable organic solvent and then dry the composite surface, as shown in block 99 , although this step is not essential to practicing this embodiment of the invention. Block 101 illustrates the next step of applying an adhesive to the treated surface of at least one composite work piece. Block 102 illustrates the step of joining a second work piece, which may be a composite or other material such as metal or ceramic, to the composite work piece on which the adhesive has been applied. Block 103 illustrates the final step of curing the adhesive. (Curing is required, depending upon the selected adhesive, although better bonds are typically produced from curable adhesives.) Embodiments of the invention may also be described as the resulting composite assembly from the bonding processes described. The joint between the composite work piece and the second work piece may include an atmospheric deposited species of the projected reactive gas beam. The composite assembly may be an aerospace structure assembled in an ambient environment. The resulting bonded composite from the novel process has a bond with a bond strength determined by cohesive failure. CONCLUSIONS Embodiments of the present invention describe a novel method of bonding composites to each other and to other materials in which a self-contained atmospheric pressure plasma device may be used to treat the surface of the composite prior to applying adhesive, then joining the materials together, and curing the adhesive. Embodiments of the invention have many advantages over the prior art: The atmospheric pressure plasma treatment can be applied to any composite material regardless of its composition, size or shape. The surface treatment is fast and effective, and adhesive bonds made to composites treated with the atmospheric pressure plasma are permanent and strong, with failure occurring within the adhesive and not at the interface between the adhesive and the composite. Embodiments of the present invention are particularly advantageous for adhesively bonding composites together in the assembly or repair of aircraft and other aerospace structures.	A method for bonding composites together that is fast and effective, and can be applied to any structure regardless of its size and shape, and its related product are disclosed. The method comprises first subjecting at least a part of a composite work piece to a low-temperature, atmospheric pressure plasma, wherein the reactive gas from the plasma is projected out of the device and onto the surface of the composite work piece, then applying an adhesive to the surface of the treated composite work piece, and joining the composite work piece together with a second work piece. The adhesive may be cured such that it forms a strong, permanent bond. The atmospheric plasma delivery device may be translated over the composite surface by hand or with a robot. The plasma device may be self-contained and portable, and can be moved to a location that is convenient for treating the composites.	1
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention pertains to apparatus for dispensing liquid and pulverulent materials. 2. Description of the Related Art The assignee of the present invention has provided a number of commercially successful automatic dispensing machines. These machines have found ready acceptance in the paint and coatings art. Examples of these machines are shown in U.S. Pat. Nos. 4,813,785; 4,967,938; 5,078,302; and 3,851,798. The machines referred to above are especially adapted for dispensing materials into containers which can be carried by hand, or which can also be delivered by conveyors to points remote from the dispensing station. For very high volume production runs, or when unusually large containers are to be filled, an unusually large source of material to be dispensed must be kept on hand at the dispensing station, and must be readily replenished, if necessary, during a work shift to keep the dispensing station fully operational with a maximum utilization. One example of such a situation is found in paint production facilities or where basic ingredients of a paint formulation are manufactured or otherwise produced. It has been found advantageous to provide what may be called "continuous" material supply, theoretically a supply of infinite size compared to the amount of material required during prolonged production runs. A typical situation may be visualized as a "tank farm" of containers coupled together through manifold arrangements to produce a source for a pipeline which runs through the production plant, with the pipeline being coupled to a dispensing apparatus. Special arrangements must be made to accommodate these so-called "infinite sources" of material and improvements in dispensing machinery for such installations have been sought. SUMMARY OF THE INVENTION It is an object of the present invention to provide dispensing apparatus for large sources of materials to be dispensed. Another object according to principles of the present invention is to provide dispensing apparatus with externally-located material storage facilities which are coupled to dispensing apparatus on board the machine. A further object according to principles of the present invention is to provide improved high volume dispensing apparatus which provides and which reduces the risks associated with dispensing materials which may be explosive or which may lead to explosive conditions under certain circumstances. These and another objects according to principles of the present invention are provided in apparatus for dispensing material into a container, comprising: a housing defining an interior volume; a dispense head in said housing for directing a flow of material therethrough in response to control commands; a plurality of pilot valves; pneumatic coupling means for coupling a pneumatic pressure source to said pilot valves; electrical control means coupled to the pilot valves so as to operate the pilot valves in response to user-determined control commands; a plurality of dispensing valves, each having inputs for receiving a flow of material, and a metering output for delivering a controlled amount of material to said dispense head and each dispensing valve having a pneumatic command input; inter-valve conduit means coupling said pilot valves to the pneumatic command inputs of respective ones of said dispensing valves; inlet conduit means coupling the inputs of said dispensing valves to an external supply source of material; and metering output conduit means coupling the metering outputs of said dispensing valves to said dispense head. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of dispensing apparatus according to principles of the present invention; FIG. 2 is a rear elevational view thereof; FIG. 3 is a side elevational view taken from the right side thereof; FIG. 4 is a side elevational view taken from the left side thereof; FIG. 5 is a perspective view of a valve manifold; FIG. 6 is a side elevational view of an alternative dispensing valve arrangement; and FIG. 7 is a top plan view of the dispensing head of FIGS. 2 and 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning now to the drawings, FIG. 1 shows dispensing apparatus according to principles of the present invention, generally indicated at 10. According to one aspect of the present invention, the dispensing apparatus does not include on-board storage of materials to be dispensed, but rather is concerned solely with handling a pressurized source of materials provided from an external source. One example of an external source is the pumping modules generally indicated at 12. Inlet and outlet conduits provide a flow path of material to be dispensed from a storage site (not shown). The pumping module induces a flow of material into conduit 14 and returns the material flow back to the storage site through an outlet conduit or return conduit 16. The pumping module 12 includes motor-driven pumps which pressurize the material, creating or augmenting the flow through conduits 14, 16, directing the material flow through dispensing apparatus 10. For example, with reference to FIG. 3, the pump outlet from module 12 produces material flow in conduit an intervalve 20, which passes through a dispensing valve 22, exiting the valve through return conduit 16 which passes through dispensing apparatus 10 and pumping module 12, as indicated in FIG. 1, to return to the storage site. As contemplated herein, the storage site may comprise canisters or other containers of varying size, may comprise a "tank farm", or may even comprise an on-site internal piping system as may be encountered in a very large material production facility. Further details concerning the pump module 12 are given in U.S. patent application Ser. No. 08/036,671, filed Mar. 25, 1994, the subject matter of which is incorporated herein as if fully set forth herein. Dispensing apparatus 10 includes a cabinet 30, comprising sheet metal panels removably mounted on a framework 32 (shown for example in FIGS. 2 and 3). The framework 32 is preferably constructed of hollow tubing. The cabinet includes a front sheet metal panel 40, a side sheet metal panel 42, a sheet metal hood 44, all of which are removable to allow access to the internal components. The sheet metal panel 46 and internal walls 48, 50 cooperate to form a cabinet enclosure generally indicated at 54. Referring to FIG. 4, an access door (see FIG. 2) has been removed to show the interior of cabinet 54, which houses electrical control equipment which controls the dispensing of material, and optionally of external apparatus such as the pumping module 12. As shown in FIG. 4, the opening of cabinet 54 has a gasket seal 56 to provide an air-tight enclosure when the access door is closed. According to one aspect of the present invention, the cabinet 54 is pressure-tight, suitable for maintaining an elevated pressure therein so as to prevent the ingress of materials being dispensed into the chamber interior, thereby providing a "safe zone" for the electronic and electrical equipment disposed within the chamber. A plurality of pressure sealing glands 58 are inserted in wall 48, to provide a pressure-tight seal for conductors, pipes and conduits, and other items passing through wall 48, which provide communication with the control circuitry components within cabinet 54. Referring again to FIGS. 1 and 4, an equipment cabinet 60 is mounted on a pedestal 62 receiving cantilever support from cabinet 30. According to one aspect of the present invention, the cabinet 60 is pressure-tight, capable of sustaining an over pressure, i.e., a pressure elevated above ambient. The pedestal 62 preferably comprises a hollow conduit for air flow entering cabinet 60 from cabinet 54. Cabinet 60 includes a hinged access door 66 and a pressure-tight gasket 68 surrounding the opening at the rear of the cabinet. A CRT monitor 70 and a keyboard 72 are mounted in cabinet 60 and provide input/output communication with a digital microcomputer control unit 76. Electrical connections between cabinets 54, 60 are located in the sealed pedestal 62 which functions as a protected cable raceway connecting the control components in the cabinets 54, 60. Referring again to FIG. 4, a conduit 78 is connected to an external source of pressurized air or suitable relatively inert gas. Air flow through conduit 78 enters cabinet 54, pressurizing the cabinet under the control of an environmental control unit 82, preferably the Model No. SE-001 EExp control unit available from Didex Corporation. Auxiliary control units 84, Model SE-003, also available from Didex, are mounted on the cabinets 54, 60. Under control of unit 82, the auxiliary units 84 release air which has been allowed to fill the cabinets 54, 60, thus purging the cabinets prior to startup of the electrical components disposed therein. Control unit 82 is programmed for a number of successive air changes within the cabinets, and thereafter maintains a preset level of overpressure within the cabinets, with a continuous air flow passing through the cabinets, and exiting the auxiliary units 84. Functionally, the cabinets 54, 60 and the interconnecting pedestal 62 cooperate to comprise a single "safe zone" for electrical control circuitry. Referring now to FIG. 2, pressurized air entering conduit 78 is directed to connected means or conduit 90 within cabinet 54, passing through pneumatic control equipment (such as user settable pressure monitoring means for monitoring and maintaining pressure at a desired level) generally indicated at 92, entering conduit 94, which, as will be seen, is used for valve actuation. The air flow is divided into conduits 96, 98 so as to be directed to manifolds 100, 102. Air flow through conduit 96 is again divided into separate flows through conduits 104, 106 so that air pressure enters both sides of manifold 100 to more rapidly pressurize the pilot valves 110 associated therewith. Similarly, air flow enters a second, substantially identical manifold 102 through conduits 112, 114. Referring to FIGS. 2 and 4, an electrical conductor 120 is coupled to control equipment within cabinet 54, passing through one of the pressure-sealing glands 58 to enter the main compartment of the dispensing apparatus. Conductor 120 is connected to a control unit 122, which in turn is coupled through conductor 124 to a pilot valve 110, opening and closing the pilot valve 110 in response to appropriate command signals from control circuitry disposed within cabinet 54. Control unit 122 is mounted on a backing plate 130. Although only a single connection is shown in FIG. 2, for purposes of drawing clarity, it should be understood that each pilot valve 110 has its own respective connection to control circuitry located within cabinet 54, such that each individual pilot valve can be selectively operated, as desired. Referring to FIG. 5, manifold 100 is preferably formed from a monolithic metal block, of preferably a stainless steel material, to form two continuous passageways extending through manifold 100, along its major axis. A first passageway extends between the opposed end faces 140 of the manifold and a completed circuit through the manifold is formed by conduits 104, 106. A second, substantially continuous passageway is formed in manifold 100 and extends generally parallel thereto. The second passageway also extends between the opposed end faces 140 and is connected to end fittings 144. As can be seen at the top of manifold 100, a series of valve-mounting ports 150 are provided, each port for a respective pilot valve 110. The ports 150 include openings 152, 154 communicating with the respective passageways through manifold 100. For example, the apertures 152 communicate with the pressurized air flow entering manifold 100 through conduits 104, 106. The apertures 154 are provided to relieve air pressure within pilot valve 110 and the pneumatic equipment connected to pilot valve 110. Turning now to FIGS. 2 and 3, each pilot valve 110 is connected to a respective dispensing valve 22 through a pneumatic piston operator 160. In the preferred embodiment, a conduit 162 is connected between pilot valve 110 and pneumatic operator 160, and provide air pressure when command signals through electrical conductor 124 open pilot valve 110. In the preferred embodiment, this causes operator 160 to function so as to open dispense valve 22, temporarily diverting material flow through the valve to a metering outlet 170. The metering outlet 170 of respective dispense valves 22 are terminated in a common dispense head 174. When a desired amount of material is diverted to dispense head 174, control signals in conductor 124 cause pilot valve 110 to close, terminating the pressurized air signal in line 162. A return spring within operator 160 overcomes the decaying air pressure signal, forcing dispensing valve 22 to close, effectively terminating the dispense operation. As will be appreciated by those skilled in the art, the return spring within operator 160 must overcome air pressure stored within the operator, entering through line 162. Air within operator 160 is forced back through pressure venting means including a line 162 leading to pilot valve 110, and to directional valving within the pilot valve, so as to exit manifold 100 through fittings 144. Referring now to FIG. 6, in order to provide faster valve closing, and to reduce back pressure during exhausting of the dispense valve, a second pressure venting means, or exhaust outline member 178 is mounted to pneumatic operator 160, with exhaust being vented directly to the atmosphere surrounding the dispense valve. As can be seen in FIG. 3, for example, the pilot valves, dispense valves, and dispense head are located within the hood member 44, so as to overhang a container to be filled. This arrangement allows the dispense valves 22 to be located very close to the dispense head 174, thereby improving dispensing accuracy. With the arrangement of the present invention, either pneumatic dispense valves or electrically operated dispense valves can be used. If electrically operated valves are to be used for the dispense valves, then electrical conductors 124 would be connected directly to the dispense valves, mounted in place of the pneumatic dispense valve 22. The dispense valves, if electrically operated, would have to be suitable for the intended purpose. For example, if hazardous materials are to be dispensed, then the electric valves should conform to local standards (i.e., must have an EEx-d rating, for example). It is generally preferred that more economical pneumatically operated dispense valves be used, with the pilot valves receiving electrical control signals, being located remote from the dispense head. With the present invention, the location of the pilot valves is not critical, and these may be located at even greater distances from the dispense valve, if desired. The drawings and the foregoing descriptions are not intended to represent the only forms of the invention in regard to the details of its construction and manner of operation. Changes in form and in the proportion of parts, as well as the substitution of equivalents, are contemplated as circumstances may suggest or render expedient; and although specific terms have been employed, they are intended in a generic and descriptive sense only and not for the purposes of limitation, the scope of the invention being delineated by the following claims.	A dispenser for liquid and pulverulent materials provides a cabinet with a pressurized chamber for electrical control equipment. Materials to be dispensed are controlled by a pilot valve and a dispense valve, for each different material to be dispensed. A dispense head is cantilevered from the cabinet, so as to overhang a container receiving the dispensed materials.	1
BACKGROUND OF THE INVENTION The invention relates to commercial production and packaging of food products, and more particularly to application of materials such as antimycotic agents as surface treatments. The invention is particularly well-suited for application of natamycin, but may also be useful for application of other antimicrobial agents, or for application of other materials such as nutritional supplements, vitamins, other food additives, and colorants. Application of natamycin to cheese shreds and small cubes has been accomplished by spraying a suspension of natamycin in an aqueous saline solution onto the shreds and cubes in a drum tumbler. For larger blocks of cheese, such as cheese chunks having a weight on the order of 8-12 oz., literature has recommended applying natamycin by dipping in a suspension of 1250 ppm natamycin, to provide a surface concentration of about 2.56-5.12 μg/cm 2 on most block cheeses. Higher surface concentrations of 5.12 μg/cm 2 or more have been recommended for blue cheese. One commercial cheese chunk packaging system that has not included application of antimycotic agents is described below. The system includes stations for cutting, weighing, confirming absence of metal, and indexing the cheese chunks, then forming, filling and sealing the packages. The cutting step involves use of cutting equipment to divide a large (e.g., 680 lb.) block of cheese into a plurality of much smaller chunks of generally rectangular configuration. The chunks typically have a weight of about 10 oz. The chunks are then weighed, indexed, and conveyed to form/fill/seal apparatus that provides an individual hermetically sealed, gas-flushed package for each chunk. The operation is carried out at high speeds. The cheese chunks may travel, e.g., at about 145 ft./minute as they enter the form/fill/seal station. One of the problems that must be addressed in application of liquids to food products in high speed packaging lines such as the one described above is avoidance of wetting of line components near the liquid application station. Application of liquid to food products can result in transfer of residue from the food products to downstream conveyors and other equipment. Also, liquid spray may be incidentally dispersed to upstream and downstream line components. This may interfere with proper operation of the equipment, and may present sanitation concerns. Saline solutions particularly can corrode conveyor bearings and other components of food-handling equipment. Another concern is that avoidance of microbial growth on the food product itself may be made more difficult where the food product has a wet exterior surface. It is a general object of the invention to provide a commercial method and apparatus for surface treatment of food products that addresses the above problems. SUMMARY OF THE INVENTION The invention provides a method and apparatus for in-line application of a surface treatment to food products at a controlled rate in compliance with applicable food-handling equipment sanitation standards, wherein the rate of application is sufficient for efficacy of the surface treatment without resulting in transfer of unacceptable quantities of residue to adjacent line components, and wherein the material is applied without tumbling of the food products. The invention is particularly useful for spray application of a liquid antimycotic agent such as natamycin to cheese chunks, at a regulated predetermined rate to provide a sufficient surface concentration to inhibit mold growth on the surfaces of the cheese chunks throughout extended periods of exposure to ambient air, without unacceptable transfer of residue to adjacent components. The invention may also be useful for application of other antimicrobial agents, or for other materials such as nutritional supplements, vitamins, and colorants. In one particular embodiment, the material applied comprises a suspension of natamycin in an aqueous saline solution. It has been found that mold growth on cheese chunks can be substantially inhibited by application of natamycin in accordance with the invention at surface concentration levels substantially lower than the recommended 2.56 μg/cm 2 , and specifically levels as low as about 0.5 μg/cm 2 have been found to be effective in preventing mold growth on refrigerated cheese chunks exposed to ambient air for extended periods. In a preferred embodiment of the invention, the process applies an average surface concentration of about 1.0 to 1.1 μg/cm 2 to ensure that an adequate concentration is applied over substantially the entire exterior surface. Application of natamycian at these average surface concentrations with the apparatus of the invention ensures that substantially all of the cheese chunk surface area has a surface concentration of at least about 0.5 μg/cm 2 . The efficacy of an antimycotic agent may be measured in terms of the number of days during which mold growth is retarded in treated samples, relative to untreated control samples. Generally, if mold growth is retarded by 45 days or more, the antimycotic may be considered effective. The absolute length of time during which mold growth is delayed depends on the mold load in the ambient air, in addition to effects of antimycotic agents. Application of antimycotic agent in accordance with the preferred embodiment of the invention has been effective in retarding mold growth by over 45 days, and has resulted in cheese chunks remaining mold-free for over 200 days in some cases, when refrigerated at typical refrigeration temperature of, e.g., 35° F. to 45° F., and exposed to ambient air. The preferred embodiments involve application to cheddar cheese or other food products having similar antimycotic requirements. The invention may also be useful with food products having different antimycotic requirement, with appropriate adjustment of the process parameters. The apparatus is preferably compact so as to avoid adding unnecessarily to the floor space requirements of the packaging line. To this end, the apparatus preferably employs only three spray disks to provide substantially complete coverage of the cheese chunks. The apparatus is preferably employed in line with equipment for cutting the cheese chunks from a larger block, then weighing the individual chunks, confirming absence of metal in the chunks, indexing the chunks, and forming, filling and sealing a hermetic, gas flushed individual package for each chunk. The invention preferably employs a disk spray system, and preferably includes a conveyor having a gap between adjacent segments to permit application of spray from beneath the chunks as they traverse the gap. To avoid penetration of the spray into the bearings of the conveyor shafts while also avoiding frictional impedance of shaft rotation, non-contacting interior shaft seals are preferably provided on the inside of the side walls at each end of one or more of the conveyor shafts. One or more of the conveyor shafts may also be provided with one or more grooves cooperating with surrounding shaft seals to inhibit flow of liquid toward the bearings. To facilitate removal from the line for cleaning and/or maintenance, the apparatus preferably is movable, and to this end may be equipped with wheels, rollers, low friction sliders, or the like, and may be mounted on a track. A spray enclosure is preferably provided to limit transfer of liquid spray to surrounding areas. The enclosure preferably surrounds the conveyor except for openings at the entrance and exit ends of the apparatus. To limit escape of fluid through these openings, the apparatus preferably includes means to remove liquid from the conveyor near its ends. The apparatus preferably complies with USDA and Dairy 3A standards. To this end, interior components of the apparatus preferably are readily removable for cleaning. The conveyor preferably comprises an O-ring conveyor, with each segment comprising a plurality of O-rings under tension extending in parallel between a pair of rotary shafts that are disposed at its opposite ends. To reduce O-ring tension and bearing loads, the shafts at opposite ends of each conveyor segment may be driven in timed relation. The apparatus preferably includes means for collecting excess spray, and the enclosure preferably includes a hood or housing. The hood includes means to direct fluid collected on interior surfaces thereof into the receptacle while preventing such fluid from dripping onto the food products, comprising one or more channels affixed to an interior surface of the hood. Each channel preferably has a minimum width sufficient to permit access by cleaning equipment and compliance with USDA and Dairy 3A standards. Fluid collected for recirculation is preferably mixed with newly introduced fluid in a reservoir. A separation device such as a basket filter may be employed in the reservoir to facilitate separation of large particles of food product from the liquid collected, so that the liquid can be recirculated without entrainment of such food particles. Additional filtration may be provided at other locations in the recirculation system BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a packaging line in accordance with a preferred embodiment of the invention. FIG. 2 is a front elevational view of the apparatus in accordance with a preferred embodiment of the invention. FIG. 3 is an end elevational view of the apparatus of FIG. 2 . FIG. 4 is a plan view of the apparatus of FIG. 2, shown with the hood removed. FIG. 5 is a perspective view of a shaft seal employed in the apparatus of FIG. 2 . FIG. 6 is a perspective view of a first wiper employed in the apparatus of FIG. 2 . FIG. 7 is a perspective view of the first wiper, installed in the apparatus of FIG. 2 . FIG. 8 is a perspective view of a second wiper, installed in the apparatus of FIG. 2 . FIG. 9 is a sectional view taken substantially along line 9 — 9 in FIG. 5 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention is preferably embodied in a method and apparatus 10 for in-line application of a surface treatment to food products 12 . In the illustrated embodiment, the apparatus is particularly adapted for application of an antimycotic agent comprising a suspension of natamycin in an aqueous saline solution. In other embodiments, the method and apparatus may be adapted for application of other antimycotic agents, or for application of other materials, e.g., nutritional supplements such as calcium, vitamins, other food additives such as lactose, or colorants. These materials might be applied individually or in combination with one another. FIG. 1 provides a schematic illustration of a food packaging line wherein the invention is embodied in an antimycotic application station. The packaging line includes a cutting station for dividing a large block of cheese weighing, e.g., 600-700 lbs. into a plurality of chunks for individual packaging. The chunks typically have a generally rectangular block configuration, with a weight in the range of about 4 oz. to 16 oz. One particular commercial chunk size has a length of between about 4 in. and 6 in., a height and width of between 1 and 2 inches, and a weight of about 10 oz. The chunks are carried downstream of the cutting station on one or more conveyors through a weighing station for determining the weight of the individual chunks, followed by a metal detector. The chunks are then transferred to a conveyor in the surface treatment station, wherein a liquid spray is applied as a surface treatment. The chunks are then conveyed through an indexing station wherein they are aligned, and finally to a form/fill/seal station, wherein an individual hermetic, gas-flushed package is formed about each chunk. The apparatus for application of the surface treatment generally includes a frame 100 , a conveyor 102 supported on the frame for transporting food products from an entrance 104 to an exit 106 , means for applying the surface treatment to food products as they are transported on the conveyor, and an enclosure or housing 108 to provide containment for the surface treatment operation. The apparatus is preferably movable so that it may be removed from the line for cleaning and maintenance while similar apparatus is substituted. To this end, the apparatus may be provided with wheels, sliders or the like, or may be movably mounted on a track disposed generally perpendicular to the packaging line. In the illustrated embodiment, wheels 110 are provided on the bottom of the frame, along with vertically adjustable feet 112 to stably support the apparatus during use. In the preferred embodiment, all interior components of the apparatus are readily capable of being cleaned and are in compliance with USDA standards and Dairy 3A standards. Conveyor While the invention may be employed with packaging lines operating at any desired speed, it is contemplated that speeds from about 30 feet per minute to about 250 feet per minute are likely to be employed. In one particular embodiment, for purposes of example, the line typically operates at about 145 feet per minute. It is desirable that the apparatus of the invention be capable of functioning at line speeds of at least 200 feet per minute, and preferably up to 250 feet per minute. In contrast to the above-mentioned methods that have been used in the past for commercial application of natamycin to cheese shreds and small cubes, wherein the shreds and cubes are passed through a drum tumbler wherein a natamycin spray is applied, the preferred apparatus conveys the food products without tumbling, which helps to preserve the weight, shape, and dimensions of the cheese chunks throughout the application process and helps to avoid excessive separation of particles from the chunks during the surface treatment operation. The illustrated conveyor comprises first and second conveyor segments 14 and 16 disposed in series, with a gap between them to permit application of surface treatment from beneath the food products as they span the gap. The first segment 14 receives product at the entrance end of the apparatus, and the second segment 16 discharges product at the exit end. The conveyor in the preferred apparatus is disposed closely adjacent conveyors at its opposite ends. Each conveyor segment in the preferred embodiment of the invention comprises a plurality of flexible, resilient longitudinal members 20 removably supported on a plurality of transverse conveyor shafts. The longitudinal members preferably comprise elastomeric O-rings. The first conveyor segment 14 is preferably driven at both ends by a first pair of conveyor drive shafts 22 and 24 , and the second conveyor segment 16 is driven by a second pair of drive shafts 26 and 28 . The drive shafts preferably have circumferential grooves to receive the O-rings. The conveyor segments are preferably driven in timed relation by a single motor 32 . The motor and conveyor drive shafts may be connected to one another for rotation in timed relation by any desired means, including belts, chains, gears, or combinations of these or other elements. In the illustrated embodiment, the motor and conveyor drive shafts are interconnected by timing belts 34 located outside of the enclosure. To limit sagging of the O-rings 20 within acceptable limits without requiring unduly high tension on the O-rings, one or more intermediate support rollers 30 may be provided between drive shafts on each conveyor segment. To avoid penetration of liquid into the bearings 36 of the conveyor drive shafts, shaft seals 38 are preferably provided on the interior of the apparatus 10 , at each end of each of the drive shafts. The bearings are preferably mounted externally of the enclosure, and spaced from the side walls 40 . The ends of each conveyor drive shaft pass through openings in the side walls of the housing 108 . At each opening, a shaft seal 38 extends inward of the side wall about the shaft. Each shaft seal preferably has a generally cylindrical bore surrounding the shaft in nonconducting relation therewith to restrict flow of fluid outward along the shaft toward the bearing without imposing substantial frictional loads on the shaft. One or more projections or grooves 42 may be provided in the shaft adjacent the shaft seal to further inhibit outward flow. In the illustrated embodiment, a helical groove is provided in each shaft, extending from the sidewall to a point slightly inward of the shaft seal, with appropriate right hand and left hand configurations provided to pump inward fluid that enters the cylindrical gap between the shaft and the shaft seal. To facilitate cleaning of the shaft seals, each of the shaft seals is removably held in place during operation by one or more fasteners 44 . The fasteners and shaft seals are configured to facilitate cleaning of the shaft seals and interior of the apparatus when the shaft seals are removed. In the illustrated embodiment, the fasteners extend through large, easily cleanable bores in the shaft seals, and engage inwardly extending studs 46 on the side wall of the housing. The employment of inwardly-extending studs to support the shaft seals avoids use of holes in the sidewalls that could accumulate fluid or food matter. Each of the illustrated fasteners comprises an enlarged head 48 engaging the inner wall of the shaft seal, and a shaft having an internally threaded socket at its end for receiving one of the studs. Each of the fasteners preferably is made of an inexpensive plastic material so as to be disposable. To limit dispersion of liquid to the exterior of the housing at the conveyor ends, wipers are preferably provided adjacent each end of the conveyor. At the entrance end, liquid received on the drive shaft from the O-rings on the bottom of drive shaft 22 may result in centrifugal spray of liquid from the outer portion of the conveyor drive shaft in an upward and outward dispersion. To address this problem, a wiper roller 50 preferably is provided to engage the O-rings as they approach the bottom of the conveyor drive shaft. The illustrated wiper roller 50 has circumferential grooves 52 formed therein to receive the O-rings and to wipe fluid therefrom. The wiper roller preferably comprises a unitary, one-piece, generally cylindrical roller having a longitudinal bore for receiving a removable stainless steel shaft. A pair of hangers 54 are provided for supporting opposite ends of the stainless steal shaft. Each hanger preferably has means for engaging fixed structural supports 56 and 58 extending inward from the housing side walls so that the hanger 54 is constrained against downward movement by the structural supports. In the preferred embodiment, the O-rings engage the top of the wiper roller, with the O-rings constraining the wiper roller assembly against upward displacement. In the illustrated embodiment, each hanger has an opening in its inner wall for receiving an end of the roller shaft, a first recess 60 opening downward and outward for receiving the first structural component; and a second, generally U-shaped slot (not shown) opening downwardly on its outer wall for receiving the second structural component. At the exit end of the apparatus, where centrifugal spray of liquid from the outer portion of the conveyor drive shaft 28 is generally directed downward and outward, fluid dispersion outside of the apparatus generally results from fluid carried upward on the interior side of the shaft, i.e., the side facing the interior of the apparatus, then outward over the top of the roller. To address this problem, a low-profile stationary wiper 62 is preferably positioned adjacent the interior side of the conveyor shaft, in nonconducting relation thereto, to remove excess fluid therefrom. The stationary wiper is preferably positioned within the O-rings in close proximity to shaft 28 , e.g., with about 5 mils of clearance, so as to remove substantially all fluid from the shaft without frictional engagement therewith. It should be appreciated that, in operation, contact may occur between the stationary wiper and the drive shaft, but that excessive friction should not result, insofar as any contact pressure should be very low. The stationary wiper preferably has a series of projections 63 in complementary engagement with the circumferential grooves on the drive shaft to remove fluid from the grooves. The wiper 62 is supported by transverse rods 64 and 66 supported by the sidewalls, and may have one or more suitable grooves or recesses for receiving the rods 64 and 66 . The wiper 62 is held in place by gravity, and includes a weight 68 to increase its stability. It can be removed for cleaning simply by lifting it from its supports 64 and 66 . Spray Applicators The surface treatment preferably employs a liquid that is applied as a spray by spin disk assemblies. In the illustrated embodiment, substantially complete coverage of each cheese chunk is obtained with the use of three spin disk assemblies 68 , 70 and 72 , one disposed beneath the conveyors, and two disposed thereabove. Each spin disk assembly comprises a rotary disk 74 driven by a motor 76 and rotated at sufficient speed to generate a spray of finely divided droplets of liquid. Liquid is dispensed onto the disks by supply conduits 78 located adjacent each of the disks. The rate of application of the surface treatment material may be varied by variation of the flow rate of liquid through the supply conduits. The lower disk unit 72 is disposed so that its spray aligns generally with the gap 18 between the conveyor segments to apply fluid to bottom surfaces of the food products 12 as they traverse the gap. The other disk units 68 and 70 are disposed above the conveyors, with each being disposed at approximately a 45° angle to the conveyor, and with the respective units being laterally offset relative to one another so that substantially complete coverage of each food product is achieved by the three units. Fluid Supply and Recirculation As noted above, the invention may be useful for application of antimicrobial agents, or for application of other materials such as nutritional supplements, vitamins, other food additives, and colorants. In one particular embodiment, the material applied comprises a suspension of natamycin in an aqueous saline solution. The concentration of natamycin in this solution is about 1250 ppm. In a preferred embodiment of the invention, the process applies an average surface concentration of about 1.0 or 1.1 μg/cm 2 to ensure that an adequate concentration is applied over substantially the entire exterior surface. The preferred embodiments involve application to cheddar cheese or other food products having similar antimycotic requirements. The invention may also be useful with food products having different antimycotic requirements, with appropriate adjustment of the process parameters. Fluid for dispensing to the disk spray units is preferably distributed from a reservoir 80 that receives new fluid from a supply tank through an inlet conduit 82 and receives additional fluid from a recirculation system that captures excess fluid beneath the conveyor. The excess fluid is collected by a receptacle 84 that preferably includes upper and lower bottom walls 86 and 88 sloping downward toward each other along the bottom of the receptacle to direct fluid into a drain conduit 90 , and therethrough into the reservoir. To maintain a low average dwell time for fluid in the reservoir, the volume of the reservoir and the volume of fluid in the reservoir preferably are small. For example, the reservoir may have a capacity of about two gallons, with only about one gallon of fluid being maintained therein during operation. A separator such as a large basket filter 92 is preferably provided in the reservoir to facilitate separation of large particles of food product from the fluid. A drain 94 at the bottom of the reservoir is connected to a pump 96 which recirculates the fluid to a distribution header 98 . The distribution header preferably includes a pair of filters 120 disposed in parallel, and appropriate valving so that either filter may be taken off line for cleaning or replacement while the apparatus continues to operate. The header then distributes the fluid to the three disk spray units through the supply conduits 78 . One or more gutters 120 collect excess fluid on the interior of the enclosure. Each gutter has a sufficient width to permit access to cleaning brushes. The preferred apparatus employs spin disk applicator equipment available from Fedco Systems Co. of Odessa, Fla. CONCLUSION From the foregoing, it should be appreciated that the invention provides a novel and improved method and apparatus for surface treatment of food products. The invention is not limited to the embodiments described above or to any particular embodiments. The invention is further described and pointed out in the following claims.	A method and apparatus for applying a material to food products in a high speed packaging line at a controlled rate in compliance with applicable food-handling equipment standards, preferably in a liquid spray, without immersion, wherein the rate of application is sufficient for efficacy of the material without resulting in transfer of unacceptable quantities of the material or carrier to adjacent line components. The invention is particularly useful for spray application of a liquid antimycotic agent to cheese chunks, at a regulated rate that provides a sufficient surface concentration to inhibit mold growth on the surfaces of the cheese chunks after extended periods of exposure to ambient air, without unacceptable transfer of residue to adjacent components in the packaging line. The invention is preferably employed in application of natamycin to cheese chunks wherein a disk spray system applies a suspension of natamycin in an aqueous saline solution. It has been found that mold growth on cheese chunks can be substantially inhibited by application of natamycin in accordance with the invention at levels as low as about 0.5 μg/cm 2 . In a preferred embodiment of the invention, the process applies an average surface concentration of about 1.0 or 1.1 μg/cm 2 to ensure that an adequate concentration is applied over substantially the entire exterior surface.	0
CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. application Ser. No. 10/146,577, entitled “Method for the Determination of Glycated Hemoglobin”, filed May 14, 2002, now U.S. Pat. No. 7,005,273 which claims priority from U.S. provisional patent application No. 60/291,361, entitled “Biofuel Cell,” filed May 16, 2001, as well as U.S. provisional application No. 60/377,886, entitled “Miniature Biological Fuel Cell That is Operational Under Physiological Conditions”, filed May 2, 2002, naming inventors Heller, Mano, Kim, Zhang and Mao, the contents of which applications are incorporated herein by reference in their entireties. BACKGROUND 1. Field of the Invention The present invention relates to a process for the determination of the amount of irreversibly glycated hemoglobin, or HbA1c, present in a sample of blood, relative to the amount of total hemoglobin. In particular, the invention incorporates in the method an electrochemical, enzyme-catalyzed reaction or reactions. The present invention also relates to devices associated with such processes or methods. 2. Background Information HbA1c is a glycated hemoglobin formed by a binding reaction between an amine group of hemoglobin and the glucose aldehyde group, for example between the amino group of the N-terminal valine of the β-chain of hemoglobin and the glucose aldehyde group. The binding reaction first forms a Schiff's base and then a stable ketoamine by Amadori rearrangement. The percentage of HbA1c (i.e. the amount of glycated hemoglobin relative to total hemaglobin in the blood) has come to be taken as a measure of the level of blood glucose control a diabetic patient has maintained for a period of two or three months prior to the measurement. As such, percentage HbA1c has become an important measurement by which health care providers can assist diabetic patients in their care. There are many known assays that can be used to determine HbA1c percentage. In recent years research efforts have focused on creating assays that are both highly accurate and fast. However, known HbA1c assays typically require a substantial number of time-consuming steps wherein the blood components must be separated and treated. In the health care context, a diabetic patient is typically guided by a physician to obtain an HbA1c measurement when the physician realizes that there is a need for such information during an office visit. The patient then provides a blood sample to a laboratory and results are returned to the physician hours or days later. Typically, the lab will use a table top analyzer of the type presently available commercially. This time lag between the patient's visit and the result of the test requires that the physician review the result long after the patient has left the office. If the physician believes that further consultation with the patient is required in light of the test result, the patient must be contacted again. Currently, there is a device sold under the name “A1c NOW” by Metrika, Inc. of Sunnyvale, Calif. This handheld and disposable device (based on technology described in U.S. Pat. No. 5,837,546 entitled “Electronic Assay Device and Method,” incorporated herein by reference) is said to provide an HbA1c test result in eight minutes using a relatively small sample of blood. The A1c NOW device is an example of the market demand for a fast method of providing an HbA1c result for either home or doctor's office use. However, the A1c NOW device is not as accurate as some laboratory assays. Thus, research has continued to focus on finding a highly accurate HbA1c assay that is also fast enough and simple enough to permit a diabetic and his or her doctor to take a blood sample during an office visit and have a trustworthy HbA1c measurement available for discussion in the same visit. SUMMARY OF THE INVENTION The present invention comprises a method of determining the amount or percentage of glycated hemoglobin in blood or a sample derived from blood, in which at least one of the assay steps is performed electrochemically. The use of electrochemical methodology can retain or improve the accuracy of other methods and potentially speed the ultimate determination. Devices providing electrochemical measurements can also be relatively small. In one embodiment, the method includes electrochemically determining the total amount of hemoglobin in a sample by electrochemically measuring, in an oxygen electroreduction reaction at a cathode, the amount of oxygen in the sample, preferably after it was exposed to air so as to assure that the hemoglobin is oxygenated. Because the amount of oxygen dissolved in aerated physiological buffer at the assay temperature in the absence of hemoglobin, termed here free oxygen, is known, the total hemoglobin may be determined by subtracting the amount of free oxygen from the total oxygen measured, recognizing the fast equilibrium Hb+O 2 ⇄HbO 2 . Electrochemically determining the total hemoglobin value can be followed by a determination of the amount of glycated hemoglobin in the sample. In the process of the invention, the cathode reaction is accomplished by contacting the sample with an enzyme. In this embodiment, the enzyme can be a copper-containing enzyme, containing four copper ions per active unit. The family of these enzymes includes, for example, laccases and bilirubin oxidases. The glycated hemoglobin can be determined in different ways. In one embodiment, the glycated hemoglobin is separated from the sample, for example by capturing it with immobilized antibodies against HbA1c or with a boronic acid modified surface. Examples of surfaces include those of small magnetic, polymer or glass beads. The percentage HbA1c can then be determined by either measuring the hemoglobin left in the sample from which the HbA1c has been removed, or by measuring the amount of glycated hemoglobin in the separated portion of the sample. The amount of glycated hemoglobin can be measured spectrophotometrically, or by an electrochemical measurement in the same manner as the total hemoglobin. In another embodiment the hemoglobin is hydrolyzed by an established method, such as digestion with a proteolytic enzyme. The ketoamines in the hydrolyzate, such as the fragments comprising the Amadori rearrangement products of the Schiff base formed of amino acids, including valine and glucose, are then determined, preferably by an electrochemical method. In the electrochemical method, the electrooxidation of the hydrolyzed Amadori rearrangement product may be catalyzed by an enzyme and a dissolved or immobilized redox mediator. The enzyme can be, for example, a fructosamine oxidase, a four copper-ion containing copper enzyme such as a laccase or a bilirubin oxidase, ceruloplasmin, or ascorbate oxidase. The redox mediators can be, for example, complexes of Os 2+/3+ , or of Ru 2+/3+ . The present invention also comprises a device associated with processes or methods disclosed herein. DETAILED DESCRIPTION The invention incorporates one or more electrochemical steps in the method of determining percentage HbA1c. The method of the invention is based on the understanding that hemoglobin, being the oxygen carrier of blood, reversibly binds oxygen, forming HbO 2 . The equilibrium Hb+O 2 ⇄HbO 2 is rapid. Because O 2 is rapidly released by HbO 2 when O 2 is depleted from the solution in an electrochemical cell, it is possible to determine the concentration of HbO 2 in light of the reaction 4H + +4e − +HbO 2 →2H 2 O+Hb. Determining Total Hemoglobin Electrochemically In the invention, it may be useful to pre-treat a blood sample by collecting the relatively large blood cells on a filtration membrane. After rinsing the collected cells with saline to remove adhering proteins, the cell membranes may be ruptured by exposing them to deionized water or a detergent. In this manner, the dissolved hemoglobin will pass the filtration membrane. The cell membranes will remain on the filter paper. In a preferred form of the invention, total hemoglobin is then determined from the sample by electroreducing the oxygen bound to the hemoglobin to water at the cathode in an electrochemical cell. The oxygen electroreduction catalyst preferably comprises a so-called “copper” enzyme such as bilirubin oxidase, a laccase, or an ascorbate oxidase. The catalyst may further comprise a redox mediator to form a “wired enzyme” arrangement. In this system, the electrical connection is between a cathode of the electrochemical cell and the oxygen reduction catalyzing enzyme, especially a copper-containing enzyme, such as bilirubin oxidase (sometimes referenced herein as BOD). Thus, in one form of the invention, it is preferred to “wire” reaction centers of an enzyme, e.g. bilirubin oxidase, to a cathode. Bilirubin oxidase catalyzes the four-electron reduction of oxygen to water. A cathode constructed with bilirubin oxidase is especially preferred as the redox enzyme can function under relatively neutral pH conditions. However, other enzymes (e.g. lacasse) may be useful in the method of the invention so long as they provide catalytic functionality for the reduction of oxygen to water. Thus, the concentration of HbO 2 can be measured by the reaction 4H + +4e − +HbO 2 →2H 2 O+Hb. This measurement may be done coulometrically. The concentration of available oxygen in arterial blood tends to be about 8 mM. Because the concentration of O 2 in water in equilibrium with air at 25° C. is known (the concentration is generally around 0.24 mM), the amount of non-Hb bound O 2 can then be subtracted in calculating the amount of HbO 2 . A cathode useful in the invention effectuates the four-electron electroreduction of O 2 to water. The blue, copper-containing oxidases, examples of which include laccases, ascorbate oxidase, ceruloplasmine, and bilirubin oxidase, catalyze the four-electron reduction of O 2 to water. The preferred enzymes are exemplified by bilirubin oxidases, which unlike laccases, retain their more than 80%, and usually retain more than 90%, of the maximal activity under physiological pH. The catalytic reduction of O 2 to water depends on the coordination of the four Cu +/2+ ions of the enzymes. The Cu +/2+ ions are classified, by their ligands, into three “types”, types 1, 2, and 3. Type 1 Cu +/2+ centers show an intense Cys S to Cu(2) charge transfer band at around 600 nm; the site accepts electrons from an organic substrate, such as a phenol, ascorbate, or bilirubin, and relays the electrons to the O 2 -reduction site. The O 2 -reduction site is a trinuclear cluster, consisting of one type 2 Cu +/2+ center and a pair of type 3 Cu +/2+ centers, their spectrum showing a shoulder at 330 nm. There are different forms of bilirubin oxidase available, such as bilirubin oxidase from Myrothecium verrucaria (Mv-BOD) and bilirubin oxidase from Trachyderma tsunodae (Tt-BOD). Bilirubin oxidases are usually monomeric proteins and have molecular weights approximately ranging from about 52 kDa to about 65 kDa. Tt-BOD is a monomeric protein with a molecular weight of approximately 64 kDa, while that of Mv-BOD is about 52 kDa. Both Mv-BOD and Tt-BOD are multicopper oxidases, each containing one type 1, one type 2, and two type 3 copper ions. These three types are defined by their optical and magnetic properties. Type 1 (blue) copper ions have a characteristic Cys to Cu (2) charge-transfer band near 600 nm. The type 1 copper center accepts electrons from the electron-donating substrate of the enzyme and relays these to the O 2 reduction site. The latter is a trinuclear cluster, consisting of a type 2 copper ion and a type 3 pair of cupric ions with a characteristic 330 nm shoulder in its absorption spectrum. In one embodiment of the invention, bilirubin oxidase from Myrothecium verrucaria could be used in a cathode electrocatalyst layer. In a cathode constructed using Mv-BOD, the electrostatic adduct of the poly-anionic Mv-BOD and its “wire”, the polycationic redox copolymer of polyacrylamide (PAA) and poly (N-vinylimidazole) (PVI) complexed with [Os (4,4′-dichloro-2,2′-bipyridine) 2 Cl] +/2+ , are immobilized on the cathode. In another embodiment of the invention, bilirubin oxidase (BOD) from Trachyderma tsunodae can be used in a cathode electrocatalyst layer. In Tt-BOD all of the ligands of the Type 2 and Type 3 Cu +/2+ centers are His (histidines), similar to ascorbate oxidase. It is believed that the full histidine coordination of the type 2 Cu +/2+ center is the underlying cause of the relative insensitivity of bilirubin oxidases to inhibition by the chloride and hydroxide anions (as are found at physiological concentration). Accordingly, it is expected that other enzymes having the three types of copper centers would also be useful as components of cathode electrocatalysts in cathodes operating under at near neutral pH. The redox potentials of the redox polymers that “wire” the cathode enzyme can be tailored for use in the invention. Redox polymers for use in the method may include PAA-PVI-[Os(4,4′-dichloro-2,2′-bipyridine) 2 Cl] +/2+ which can be prepared as follows: 4,4′-Dinitro-2,2-bipyridine N,N′-dioxide was prepared as described in Anderson, S.; Constable, E. C.; Seddon, K. R.; Turp, E. T.; Baggott, J. E.; Pilling, J. J. Chem. Soc., Dalton Trans. 1985, 2247-2250, and Kenausis, G.; Taylor, C.; Rajagopalan, R.; Heller, A. J. Chem. Soc., Faraday Trans. 1996, 92, 4131-4135. 4,4′-dichloro-2,2′-bipyridine (dc1-bpy) was synthesized from 4,4′-dinitro-2,2′-bipyridine N,N′-dioxide by modifying the procedure of Maerker et al. (see Anderson, S., supra and Maerker, G.; Case, F. H. J. Am. Chem. Soc. 1958, 80, 2475-2477.). Os(dcl-bpy) 2 Cl 2 was prepared as follows: (NH 4 ) 2 OsCl 6 and ″dc1-bpy were dissolved in ethylene glycol in a 1:2 molar ratio and refluxed under argon for 1 hour (yield 85%). The Os(dcl-bpy) 2 Cl 2 was then complexed with the 1:7 polyacrylamide-poly(N-vinylimidazole) (PAA-PVI) copolymer and purified as described in Zakeeruddin, S. M.; D. M. Fraser, D. M.; Nazeeruddin, M.-K.; Gratzel, M. J. Electroanal. Chem. 1992, 337, 253-256 to form the PAA-PVI-[Os(4,4′-dichloro-2,2′-bipyridine) 2 Cl] +/2+ redox polymer. Those skilled in the art are aware of numerous variations that can be prepared and used as redox polymers according to the invention. Determination of the HbA1c Percentage Once the total hemoglobin has been measured, the HbA1c/Hb ratio can be determined by separating the HbA1c fraction from the sample. The HbA1c, which can be converted to HbA1cO2, can then be measured indirectly and electrochemically using the same method as for the total hemoglobin. Alternatively, these fructosyl amines may be subject to direct enzyme catalyzed electro-oxidation, for example using fructosyl amine oxidases having FAD/FADH reaction centers, or by one of the copper enzymes. The following are examples of suitable methods which incorporate the separation and HbA1c assay steps. EXAMPLE 1 Affinity gel columns can be used to separate bound, glycosylated hemoglobin from the nonglycosylated fraction. The gel contains immobilized m-aminophenylboronic acid on cross-linked, beaded agarose. The boronic acid first reacts with the cis-diol groups of glucose bound to hemoglobin to form a reversible 5-membered ring complex, thus selectively holding the glycosylated hemoglobin on the column. Next, the nonglycosylated hemoglobin is eluted. The ring complex is then dissociated by sorbitol, which permits elution of the glycosylated hemoglobin. Using affinity chromatography, absorbances of the bound and nonbound fractions, measured at 415 nm, are used to calculate the percent of glycosylated hemoglobin. EXAMPLE 2 Magnetic beads that are <1 μm (available from Bangs Laboratories), on which antibodies against HbA1c would be immobilized, can be mixed with a citrate-solution diluted blood sample. Two measurements are performed, one on the entire sample, and a second on the re-oxygenated Hb1Ac bound to the magnetic beads, after their removal to a chamber of an electrochemical cell. Alternatively, the second measurement can be on the residual Hb, after the magnetic separation of the bead-bourid HbA1c. EXAMPLE 3 Two samples of the lysed red blood cells in citrate buffer can be coulometrically assayed in two chambers. In Chamber 1, the total HbO 2 would be measured. Chamber 2 contains the immobilized HbA1c-specific antibody. Either of the two would capture HbA1c without capturing Hb. After rinsing or passage of citrate buffer through Chamber 2 (e.g. by repeated filling through capillary action and touching the edge of the chamber to filter paper), the chamber would contain only HbA1cO 2 . The HbA1cO 2 would be assayed electrochemically (preferably coulometrically) by its electroreduction, 4H + +4e − +HbA1cO 2 →2H 2 O+ HbA1c. The HbA1c/Hb ratio can then be calculated from the two coulometric measurements. EXAMPLE 4 As in example 3 above, except that the two coulometric measurements would be performed in a single chamber. The chamber, which would contain the immobilized HbA1c capture agent, would be filled with a citrate solution of the lysed red blood cells. First, the total HbO 2 would be electrochemically (preferably coulometrically) measured. Next, the unbound Hb, but not the bound HbA1c, would be rinsed out, the HbA1c would be re-equilibrated with air, and its amount would be coulometrically measured. Thus, the assay of the invention, in one form, can comprise a method of determining the ratio of HbA1c to total Hb in blood, the method comprising obtaining a blood sample; electrochemically determining the total amount of hemoglobin in the sample, or in a treated portion of the sample; electrochemically determining the amount of HbA1c in the sample; and calculating the ratio of HbA1c to total hemoglobin. In a preferred form the method of electrochemically determining the total amount of hemoglobin in the sample is accomplished by placing the sample in an electrochemical cell in which, at the cathode, a cathode enzyme is bound, for example using a redox polymer. In this method, it is preferred that the enzyme be a laccase or a bilirubin oxidase which will electroreduce oxygen bound to the hemoglobin to water. The hemoglobin content is determined from the oxygen content. In another form of the invention the electrochemical determination of HbA1c fraction can be accomplished by one of two methods. In a first method, the A1c containing fraction of the hemoglobin is separated by physical means, such as by use of an HbA1c specific antibody. Under appropriate conditions the HbA1c then present in the form of HbA1cO 2 can then be electrochemically determined by electroreduction of the oxygen. (again with an enzyme selected to accomplish the four electron reduction of oxygen). In a second method, the glycated protein (a fructosyl amine) can be directly oxidized on cross-linked poly(N-vinyl imidazole) based redox polymer films (without an enzyme) of sufficiently positive oxidizing potential. Alternatively, enzymatic electrooxidation of the fructosyl amines can be used for this part of the determination. Finally, the invention comprises an electrochemical method for the determination of HbA1c (or HbA1c/Hb ratio) comprising determining from a starting sample, in an electrochemical cell, the total amount of hemoglobin (e.g. by measuring bound oxygen), separating the HbA1c component from the sample using an HbA1c capturing agent, and measuring hemoglobin content in the captured or non-captured portion of the sample. Devices for accomplishing the method of the invention are preferably small. By incorporating electrochemical steps, it may be possible to prepare biosensor strips which include a cathode at which the chemistry discussed herein is placed, as well at which the necessary anode is constructed. Such strips can be prepared using techniques presently used for making commercially available biosensor strips that are used for glucose determinations, such as the FreeStyle blood glucose system sold by TheraSense, Inc. Samples could then be applied to these strips and the strips placed in the measuring instrument (meter) to be “read.” By constructing a portion of the equipment in the form of electrochemical biosensor strips, the electrochemical method of the invention provides a significant potential advantage of creating a smaller analysis device while providing accurate results.	A method of determining the percentage of glycated hemoglobin in a blood sample is disclosed wherein at least one of the assay steps is performed electrochemically. The method includes determining the total amount of hemoglobin in a sample by electrochemically measuring, in an oxygen electroreduction reaction at a cathode, the amount of oxygen in the sample. Because the amount of oxygen dissolved in the sample is known, the total hemoglobin is determined by subtracting the amount of free oxygen from the total oxygen measured, recognizing the fast equilibrium Hb+O 2 ⇄HbO 2 . This can be followed by determining the amount of glycated hemoglobin in the sample. The cathode reaction is accomplished by contacting the sample with an enzyme, the enzyme being a copper-containing enzyme having four copper ions per active unit. The family of these enzymes includes, for example, laccases and bilirubin oxidases. A device associated with such a process or method is also provided.	5
[0001] The present application claims the priority of the China Patent Application No. 201210102518.7, filed on Apr. 9, 2012, which is incorporated herein by reference in its entirety. FIELD OF THE INVENTION [0002] The invention relates to a fabrication of large scale semiconductor integrated circuit, more particularly, to a device integration process in the large scale integrated circuit. BACKGROUND OF THE INVENTION [0003] As Moore law proceeds to the technical node of 22 nm, the traditional planar field effect transistor can not meet the requirements of low power consumption and high performance. In order to overcome the short channel effect and improve the drive current density, field effect transistors with a fin-shaped channel (FinFET) of 3-dimensional structure has been introduced into the large scale integrated circuits. This structure has very excellent immunity to short channel effect and very high drive current owing to the large gate-controlling area and narrow channel depletion region. [0004] There are many challenges in FinFET fabrication to limit the applications of FinFET in large scale integrated circuits. One of the difficulties lies in the etching of the 3-dimesional gate profile, which is due to the surface fluctuation occurred when depositing gate materials. The gate materials have large surface fluctuation since they are deposited on 3-dimensional fin-shaped silicon strips. Thus, it is difficult to focus during the lithography process and it is difficult to completely remove the gate materials on sidewalls of the fin unless using a large over-etching process. However, the large over-etching process may cause damage to the silicon active region. This problem is serious especially when employing a high resolution lithography process below 22 nm. Hence, the product yield is restricted. [0005] Several methods have been proposed to perform a planarization process firstly, and then to perform a photolithgraphy process and an etching process. For example, it is disclosed in U.S. patent publication US2005056845-A1 that an entire planar gate material is obtained by covering the fin with two gate layers of different materials, and then performing a planarization process to the first gate layer through a chemical mechanical polishing method. This method requires firstly covering the top of the fin with a layer of insulation dielectric to protect the top of the fin from damage. However, this method can neither form triple gate structure nor reduce the burden of the gate etching process. [0006] The problem caused by the gate etching residue on sidewalls is solved in U.S. patent publication US2005170593-A1 by Damascus fake-gate process, that is, by etching the trench with a gate electrode mask and then refilling the gate material, which may address the problem caused by the gate etching residue on fin sidewalls. Thus, the reliability of product is improved. However, this method can not form the triple gate structure, and the gate strip width on the top of the fin and the gate strip width on sidewalls can not be formed in a self-aligned manner. SUMMARY OF THE INVENTION [0007] In order to solve the above problems in the fabrication of 3-dimensional triple gate FinFET structure on bulk silicon, the present invention proposes a gate-last integration process based on the planarization process, which is suitable for the large scale integrated circuit. According to embodiments of the present invention, a flat gate surface is obtained and the problem of gate etching residue on fin sidewalls is avoided. In addition, according to embodiments of the present invention, the high-K metal gate process may be effectively integrated; the increase of equivalent oxide thickness and the work function drift are avoided, so that an excellent device performance may be obtained. [0008] The method according to an embodiment of the present invention may include the following steps: [0009] 1) forming a STI isolation layer on a bulk silicon substrate, and performing a well implantation and a channel ion implantation to the active region and performing an annealing process; [0010] 2) exposing the silicon surface of the active region, depositing a sacrificial gate oxide layer, forming a dummy gate on the sacrificial oxide layer, wherein the top of the dummy gate is covered by a composite hard mask including silicon oxide and silicon nitride; [0011] 3) removing the sacrificial oxide layer covered on the drain and source regions, depositing a thin film of silicon nitride as an implantation mask for the drain and source regions to perform a drain and source LDD implantation and Halo implantation, and performing a rapid flash annealing of milliseconds; [0012] 4) depositing a silicon nitride layer, performing a photolithgraphy process, performing an anisotropic dry etching process to the silicon nitride layer with the photoresist as a mask, to form silicon nitride spacers of the dummy gate and expose the drain and source regions, and then performing an etch-back process to the STI isolation layer around the silicon mesa of the drain and source regions; [0013] 5) removing the photoresist, performing a drain and source epitaxial growth on the exposed source and drain, and then performing an additional drain and source implantation and flash annealing of millisecond to activate the drain and source dopant; [0014] 6) depositing a silicon oxide layer so as to cover the entire surface of silicon wafer; then performing a thinning and planarization of the silicon oxide layer through a chemical mechanical polishing process with the silicon nitride layer on the top of the dummy gate as a stop layer; then performing a dry etch-back process to the silicon oxide layer, till ⅓-½ of the height of the dummy gate; [0015] 7) depositing a silicon nitride layer, performing a thinning process to the silicon nitride layer through a chemical mechanical polishing process till the silicon oxide layer on top of the dummy gate or the polysilicon dummy gate is exposed; with the remaining silicon nitride layer as a hard mask, removing the polysilicon to expose the STI oxide layer under the dummy gate; performing a dry etch-back process to this portion of the STI oxide layer to form fin-shaped channel region; [0016] 8) wet etching the remaining silicon oxide layer on the top and sides of the fin-shaped channel region, depositing the gate dielectric and gate electrode material to complete the device structure. [0017] During implementation of the present invention, the following specific operations may be taken. [0018] In Step 1), a silicon oxide layer is grown and a silicon nitride layer is deposited on the bulk silicon substrate, the pattern of active region is transferred onto the silicon nitride layer by the lithography process, the silicon nitride layer is etched with the photoresist as a mask, and the silicon oxide layer and the bulk silicon is dry-etched with the silicon nitride layer as a hard mask to form a shallow trench, the depth of the shallow trench being within the range of 1000 Å-3000 Å; the shallow trench is filled through a high aspect ratio silicon oxide deposition process and a silicon oxide layer covers the entire silicon surface ; the surface of the silicon oxide layer is planarized through the chemical mechanical polishing process till the hard mask layer of silicon nitride is expoesd, to form the STI isolation layer. [0019] After forming the STI isolation layer in step 1), the etching process and implantation for the well are performed, then the silicon nitride hard mask layer on the active region is removed, and the channel ion implantation is performed. [0020] In step 2), the dummy gate may be formed by: depositing a thin layer of silicon oxide on the exposed surface of the active region as a sacrificial gate oxide layer through an atomic layer deposition (ALD) process, then depositing a layer of polysilicon or amorphous silicon on the sacrificial gate oxide layer as the dummy gate material, and sequentially depositing a silicon oxide layer and a silicon nitride layer as a hard mask; then performing a gate patterning with the photoresist as a mask to etch the silicon nitride layer on the top; and, removing the photoresist and performing the dry etching process to the silicon oxide layer and the gate layer with the silicon nitride layer on the top after etching as a hard mask, to eventually stop on the sacrificial gate oxide layer. [0021] In step 3), the energy of LDD implantation is 500 eV-5KeV, the implantation dose is 1E14 cm −3 -2E15 cm −3 , the implantation angle is 0-7 degrees, and the LDD implantation impurity may be P and/or As for N-type transistor and be B and the compound thereof for P-type transistor. For both types of transistors, Ge or C implantation may be selected as pre-amorphization implantation. The energy of Halo implantation is 1 KeV-45 KeV, the implantation dose is 1E12 cm −3 -1E14 cm −3, the implantation angle is 15-30 degrees, and the Halo implantation impurity may be B and the compound thereof for N-type transistor and be P and/or As for P-type transistor. For both types of transistors, Ge or C implantation may be selected as the pre-amorphization implantation. [0022] In step 4), the etch-back depth of the STI isolation layer around the drain and source regions is 100 Å-2000 Å. The etching condition with high selectivity of silicon oxide to silicon is employed when the etch-back process is performed to the STI isolation layer. [0023] In step 5), SiGe material is epitaxially grown on the drain and source of P-type transistor; and Si or SiC material is epitaxially grown on the drain and source of N-type transistor. The epitaxial thickness in the direction of the fin width typically does not exceed ⅓ of the spacing distance of two fins adjacent to each other in the integrated circuit. [0024] In step 6), the silicon oxide deposition is performed through the high density plasma chemical vapor deposition (HDP CVD) so as to cover the entire surface of silicon wafer, and then the thinning, planarization, and etch-back process are performed. [0025] In step 7), the dummy gate is removed by performing the dry etch process firstly and then the dummy gate is removed completely through the wet etch process. [0026] In step 7), the STI isolation layer under the dummy gate is etched back, the etch-back depth being 100 Å-2500 Å. As same as step 4), an etching condition with high selectivity of silicon oxide to silicon is high is employed during the etching process. [0027] In step 8), the deposition of the high-K dielectric and metal gate electrode is performed, and the thinning and planarization of the metal gate are then performed through the chemical mechanical polishing process to stop on the silicon nitride layer, thereby resulting in 3-dimensional triple gate FinFET device. [0028] After step 8), the back-end process of transistors are performanced, including contact hole etching, metal deposition, forming metal electrode and interconnection wire. [0029] The inventive concept of the present invention lies in that the fin structure is only formed in the gate electrode region as following: performing the photolithgraphy process and the first etching of the dummy gate on the flat surface formed by the STI chemical mechanical polishing process, forming the drain and source region, depositing a medium dielectric layer, polishing the medium dielectric layer till the top of the dummy gate is exposed, removing the dummy gate material by the dry etch process and the wet etch process, and continuously etching the STI dielectric layer with the hard mask formed of the medium dielectric layer to form the Fin structure only in the gate electrode region. After that, the true gate dielectric and gate electrode material are deposited to complete the device structure. [0030] The present invention has following advantages: (1) the surface of the gate is flat, meeting the flatness requirements for the photolithgraphy below 22 nm; (2) the etching amount of the dummy gate is small to enable forming a steep and straight pattern, whereby reducing the limitation on gate pitch and the influence of parasitical capacitance; (3) the fin structure is only formed in the gate region so as to avoid the gate material remaining on sidewalls of drain and source, thus improving the isolation reliability of the device; (4) the 3-dimensional high-K metal gate structure can be achieved with the dummy gate process to improve the threshold control capability of FinFET; (5) the method of embodiments of the present invention is completely compatible with the process of bulk silicon planar transistor and the processing cost is low. BRIEF DESCRIPTION OF THE DRAWINGS [0031] FIG. 1 is a schematic diagram of a device structure after performing a silicon active region etching of step 3 according to an embodiment, wherein (a) is a top view, (b) is a cross sectional view taken in direction A-A′, and (c) is a cross sectional view taken in direction B-B′. [0032] FIG. 2 is a schematic diagram of a device structure when performing the well implantation after the STI filling and CMP of steps 6 and 7 according to an embodiment, wherein (a) is a top view, (b) is a cross sectional view in direction A-A′, and (c) is a cross sectional view taken in direction B-B′. [0033] FIG. 3 is a schematic diagram of a device structure when removing the silicon nitride hard mask and performing channel doping implantation of steps 8 and 9 according to an embodiment, wherein (a) is a top view, and (b) and (c) are cross sectional views taken along A-A′ and B-B′, respectively. [0034] FIG. 4 is a schematic diagram of a device structure when exposing the silicon surface of the active region of step 11 according to an embodiment, wherein (a) is a top view, and (b) and (c) are cross sectional views taken along A-A′ and B-B′, respectively. [0035] FIG. 5 is a schematic diagram of a device structure after performing polysilicon gate etching of step 14 according to an embodiment, wherein (a) is a top view, and (b) and (c) are cross sectional views taken along A-A′ and B-B′, respectively, and a composite hard mask of silicon oxide and silicon nitride is located on top of the polysilicon gate. [0036] FIG. 6 is a schematic diagram of a device structure when performing LDD and Halo implantations of step 16 according to an embodiment, wherein (a) is a top view, and (b) and (c) are cross sectional views taken along A-A′ and B-B′, respectively, and the gate, the active region and the STI region are covered with a silicon nitride layer which is used as an implantation screeninglayer. [0037] FIG. 7 is a schematic diagram of a device structure when performing the first etch-back to the STI silicon oxide layer around the drain and source after forming the silicon nitride spacers of step 19 according to an embodiment, wherein (a) is a top view, and (b) and (c) are cross sectional views taken along C-C′ and B-B′, respectively. [0038] FIG. 8 is a schematic diagram of a device structure after performing drain and source epitaxial growth and additional implantation of steps 20 and 21 according to an embodiment, wherein (a) is a top view, and (b) and (c) are cross sectional views taken along C-C′ and B-B′, respectively, and the region denoted by spots in the drain and source is a metallurgical junction formed by an in-situ impurity out-diffusion during the drain and source epitaxial growth. [0039] FIG. 9 is a schematic diagram of a device structure after performing silicon oxide and silicon nitride refilling and CMP to remove the silicon nitride and silicon oxide layers on top of the polysilicon dummy gate of step 27 according to an embodiment, wherein (a) is a top view, and (b) and (c) are cross sectional views taken along A-A′ and B-B′, respectively. [0040] FIG. 10 is a schematic diagram of a device structure when performing the second etch-back to the STI layer to form partial fin structure after removing the polysilicon layer of step 29 according to an embodiment, wherein (a) is a top view, and (b) and (c) are cross sectional views taken along A-A′ and B-B′, respectively. [0041] FIG. 11 is a schematic diagram of a device structure after re-growing high-K dielectric and metal gate material in the dummy gate region of step 30 according to an embodiment, wherein (a) is a top view, and (b) and (c) are cross sectional views taken along A-A′ and B-B′, respectively, and reference sign 113 refers to high-K gate dielectric, reference sign 114 refers to work function material, and reference sign 115 refers to A1 material used as the filling material; as can be seen, the high-K dielectric and the metal gate cover on the fin in a shape of “Π”, forming a triple gate control structure. DETAILED DESCRIPTION OF EMBODIMENTS [0042] The present invention can be implemented through following specific embodiments, however, is not limited to the process parameters range mentioned in the embodiments, and similar inventive spirit shall be regarded as the extension of the present invention. [0043] A FinFET device is fabricated by following steps. [0044] 1. A silicon oxide layer and a silicon nitride layer are deposited on a bulk silicon substrate 101 along the crystal orientation of (100) or (110) as a hard mask for the first etching, wherein the thickness of the silicon oxide layer 102 is 50 Å-200 Å, and the thickness of the silicon nitride layer 103 is 70 Å-500 Å. [0045] 2. A pattern of the active region is transferred to the silicon nitride layer 103 with the mask for the first lithography process, and the photoresist is used as a hard mask to etch the silicon nitride layer, and this etching is stopped on the silicon oxide layer 102 . [0046] 3.The photoresist is removed, and the silicon oxide layer and the bulk silicon are etched with the silicon nitride layer as a hard mask to form a shallow trench. As shown in FIG. 1 , the depth of the shallow trench is 1000 Å-3000 Å, the angle between the ramp and the silicon surface is 80-90 degrees. After the etching is completed, the depth of remaining silicon nitride hard mask 103 is 50 Å-300 Å. [0047] 4. The corners of the silicon active region obtained by etching are rounded through an in-situ steam generated oxidation, and the thickness of the generated silicon oxide layer is 10 Å-50 Å. [0048] 5. The remaining silicon trench is refilled through a silicon oxide deposition process with a high aspect ratio, the refilling thickness being 3000 Å-7000 Å, and the refilled silicon oxide covers the entire silicon surface. [0049] 6. The surface of the silicon oxide layer is planarized through the chemical mechanical polishing process, and the silicon oxide layer is thinned till the silicon nitride hard mask layer is exposed, to form a structure in which the active region of the device is surrounded by the silicon oxide layer and the active region is covered with the silicon nitride layer. This silicon oxide region is referred to STI isolation layer 104 , as shown in FIG. 2 . [0050] 7.The photolithograph process and implantation process are performed to the well (see FIG. 2 ). [0051] 8. The STI isolation layer 104 is etched back with a diluted hydrofluoric acid solution (DHF), the amount of etch-back is obtained by subtracting about 30 Å from the thickness of the silicon nitride hard mask. Then, the silicon nitride layer 103 is removed with a hot phosphoric acid, as shown in FIG. 3 . [0052] 9. The channel doping ion implantation is performed (see FIG. 3 ). [0053] 10. The mask for the ion implantation is removed, and the thermal annealing is performed by the RTA process, the annealing temperature being 1000° C.-1100° C., the annealing time is 10 seconds-1 hour. After annealing, the impurity implanted via the well implantation and the channel implantation are activated and diffused evenly into the active region. [0054] 11.The thermal oxide layer on the top of the active region is removed with DHF and the silicon oxide layer 104 which is used as the STI isolation layer is etched back, so that the silicon surface of the active region is exposed and keeps a smaller step (or recess) with the STI region, as shown in FIG. 4 . The height difference between the steps is smaller than 50 Å. [0055] 12.A thin layer of silicon oxide is deposited as a sacrificial oxide layer 105 through the atomic layer deposition (ALD) process, the deposition thickness being 15 Å-30 Å, on which a layer of polysilicon or amorphous silicon is deposited as dummy gate. The thickness of the dummy gate 106 is 500 Å-1500 Å. A Silicon oxide layer 107 with a thickness of 100 Å-200 Å and a silicon nitride layer 108 with a thickness of 300 Å-800 Å are sequentially deposited on the dummy gate 106 as a hard mask. [0056] 13.The lithography process is performed to form the gate pattern, and the top silicon nitride 108 is etched with the photoresist as a mask. [0057] 14. After removing the photoresist, a dry etching process is performed to the silicon oxide layer 107 and the polysilicon dummy gate 106 with the silicon nitride layer 108 as a hard mask, and the thy etching process stops on the sacrificial gate oxide layer 105 , as shown in FIG. 5 . [0058] 15. The sacrificial gate oxide layer 105 covering the drain and source regions is removed with DHF, and the thin silicon nitride layer 109 deposited through the ALD process is used as a LDD and Halo implantation mask for the drain and source, the thickness of the layer 109 being about 10 Å-30 Å, as shown in FIG. 6 . [0059] 16. The LDD and Halo implantation is performed via the thin silicon nitride layer 109 covering the drain and source (see FIG. 6 ), wherein the energy of the LDD implantation being 500 eV-5 KeV, the dose being 1E14 cm −3 -2E15 cm −3 , the implantation tilt angle is 0-7 degrees, and the LDD implantation impurity may be P and/or As for N-type transistor and be B and the compound thereof for P-type transistor. For both type transistors, Ge or C implantation may be selected as a pre-amorphization implantation. The energy of the Halo implantation may be 1 KeV-45 KeV, the implantation dose may be 1E12 cm −3 -1E14 cm −3 , the implantation tilt angle may be 15-30 degrees, and the Halo implantation impurity may be B and the compound thereof for N-type transistor and P and/or As for P-type transistor. For both type transistors, the Ge or C implantation may be selected as the pre-amorphization implantation. [0060] 17. The annealing is implemented through a rapid flash annealing of milliseconds (flash RTP), to completely activate the impurity, cure implantation defects to avoid the enhanced diffusion, the annealing peak temperature being 900° C.-1050° C. and the annealing time being 0.1 ms-10 ms. [0061] 18. A silicon nitride layer is deposited through the ALD process, the deposition thickness being 50 Å-150 Å, and a lithography process is performed and the silicon nitride sidewalls 110 are formed through the anisotropic dry etching process, to expose the silicon surface of the drain and source regions. After etching, the thickness of the silicon nitride layer remaining on the top of the dummy gate may be about 200 Å, and the lost amount of the silicon surface may not exceed 30 Å. [0062] 19. A STI silicon oxide etching process is performed with the photoresist and the silicon nitride layer (the silicon nitride layer remaining on the top of dummy gate and the silicon nitride sidewalls on both sides of the dummy gate) as a mask, so that the silicon oxide layer 104 around the silicon mesa of the drain and source regions forms an etch-back portion, the depth thereof being 100 Å-2000 Å, as shown in FIG. 7 . [0063] 20. After removing the photoresist, the drain and source 111 are raised through a selective epitaxial growth with the exposed silicon mesa as a crystal seed window (as shown in FIG. 8 ). As for the P-type transistor, SiGe material is grown with the growth amount being 100 Å-500 Å, the content of Ge being 30%-50%, the in-situ B doping amount being 1E19 cm −3 -1E21 cm −3 . As for the N-type transistor, Si or SiC material is grown, with the growth amount being 100 Å-500 Å, the in-situ P doping amount being 1E19 cm −3 -1E21 cm −3 . The epitaxial thickness in the direction of the fin width (shown in FIG. 8 as W) typically does not exceed ⅓ of the spacing distance of two fins adjacent to each other in integrated circuit. [0064] 21.After the lithography process, the N+ or P+ doped region is exposed and then an additional implantation for the drain and source is performed. As for the N-type transistor, Ge and C are firstly implanted, and thereafter As and/or P are implanted, the implantation energy and dose for those are: Ge: 15 KeV-35 KeV, dose: 1E14 cm −3 -1E15 cm −3 ; C: 5 K-20 K, dose: 1E13 cm −3 ˜1E15 cm −3 ; As: 5 K-20 K, dose: 1E15 cm −3 -1E16 cm −3 ; and P: 10 K-30 K, dose: 1E13 cm −3 ˜1E15 cm −3 . As for the P-type transistor, Ge is firstly implanted, and thereafter B is implanted, the implantation energy and dose for those are: Ge: 15 KeV-35 KeV, dose: 1E14 cm −3 ˜1E15 cm −3 ; and B: 0.5 KeV-20 KeV, dose: 5E12 cm −3 ˜1E15 cm −3 . [0065] 22. After the implantation, the annealing is implemented through the flash annealing of milliseconds, the annealing peak temperature being 900° C.-1050° C., and the annealing time being 0.1 ms-10 ms. [0066] 23. A silicon oxide layer is deposited through a high density plasma chemical vapor deposition (HDP CVD), to cover the entire surface of the silicon wafer and to remove all cavities therein, the deposition thickness being about 1000 Å-3000 Å. [0067] 24. The silicon oxide layer is thinned and planarized through the chemical mechanical polishing process, with the silicon nitride layer remaining on the top of the dummy gate as a stop layer. [0068] 25. The silicon oxide layer is etch-backed to ⅓-½ of the height of the dummy gate through a dry etching process. [0069] 26. A silicon nitride layer is deposited, the deposition thickness being 300 Å-500 Å. [0070] 27. The silicon nitride layer is thinned through the chemical mechanical polishing process, which stops on the silicon oxide layer 107 on the top of the dummy gate or on the dummy gate 106 with the thickness of the silicon nitride layer 112 remaining on both sides of the dummy gate is about 100 Å-200 Å, as shown in FIG. 9 . [0071] 29. The dummy gate 106 is etch-backed to a remaining thickness of about 100 Å through dry etching, with the remaining silicon nitride layer 112 as a hard mask, and then the remaining dummy gate is stripped off with tetrabutyl ammonium hydroxide (TMAH) solution to expose the STI silicon oxide layer 104 of the isolation region. [0072] 29. The STI silicon oxide layer 104 is etched through the dry etching process with the silicon nitride layer as a hard mask to form a fin-shaped channel region, the etching depth being 100 Å-2500 Å, as shown in FIG. 10 . [0073] 30. The silicon oxide layer remaining on the top and sidewalls of the fin-shaped channel region is removed with the DHF and a high-K dieletric deposition and the metal gate electrode deposition are performed. A thermal annealing is performed between the high-K dielectric deposition and the metal gate deposition in order to suppress interface dipoles and to recover interface traps. Specifically, the metal gate is formed by: depositing a layer of work function material on the high-K electric layer through the PVD, the deposition thickness being about 50 Å-100 Å; depositing a metal filling material (such as A1) through the PVD to fulfill the entire gate trench; and performing the thinning and planarization process which stops on the silicon nitride layer 112 to the filling material, work function material and high-K gate dielectric, whereby the metal gate is obtained, as shown in FIG. 11 , wherein the work function material is located between the filling metal material 115 and the high-K gate dielectric 113 . [0074] 31. The etching process for the contact holes is performed sequentially and the landing region of the etching process is located on the N+ and P+ raised drain and source 111 . Then a Ni/Pt layer is deposited through the ALD process, and the annealing for metal silicide is performed through the flash RTP. [0075] 32. The sequential back-end processes are similar as those of current 45 nm and 32 nm copper interconnection processes, which are used to complete interconnection. The embodiments as described above are not intended to limit the present invention, and various alternations and modifications can be made to those embodiments by those skilled in the art without departing the spirit and scope of the present invention, therefore the scope of protection of the present invention is defined by the appended claims.	Systems and methods of fabricating a FinFET in large scale integrated circuit are disclosed. One illustrative method relates to a dummy gate process, wherein the fin structure is only formed in the gate electrode region by performing a photolithography process and an etching of a first dummy gate on a flat STI surface using chemical mechanical polishing, forming drain and source regions, depositing a medium dielectric layer, polishing the medium dielectric layer till the top of the first dummy gate is exposed through the chemical mechanical polishing process again, removing the dummy gate material via a dry etching and a wet etching, and continuously etching the STI dielectric layer with the hard mask formed by the medium dielectric layer, thereafter performing the deposition of real gate dielectric and gate electrode material to complete the device structure.	7
RELATED APPLICATION This application claims the benefit of U.S. Patent Provisional Application Ser. No. 60/501,357, filed Sep. 9, 2003, and entitled “Connector Apparatus and Method of Coupling Bioprocessing Equipment to a Media Source,” the entirety of which is hereby incorporated by reference. TECHNICAL FIELD This invention relates to a connector apparatus and a method for implementing the same. More particularly, this invention relates to a connector apparatus for coupling a media source to a bioreactor in a sterilized environment. BACKGROUND Bioprocessing systems are widely used for culturing biomaterial or producing and designing drugs used in pharmaceutical applications. Typically, these systems employ bioreactors and media dispensers connected by tube and valve assemblies. Multiple steam traps and a flow hood are often incorporated to sterilize the system from contaminants. Typically, bioreactors or culture environments and media dispensers have consisted of large vats for producing such biomaterials. Typically, the components used in the assembly were reusable stainless steel components. However, this can require a complex and time consuming coupling procedure. In addition, flow hoods, such as laminar flow hoods, can be cumbersome and inconvenient as they are moved in and out of the processing environment. As more specific cultures and designer drugs are being produced, and as more specific growth media provided to a bioreactor are being developed, there is a need for an improved and less complex bioprocessing system. Furthermore, present designs using multiple steam traps and complex tube/valve assemblies create a bioprocessing system that is difficult to operate and may allow for increased margin of error with respect to sterilization of the system. Therefore, there is a need for a less complex system that is more convenient to handle, and that can simplify the more specific pharmaceutical designs associated with particular biomaterial production. The present invention, as described herein, provides improvements upon one or more of the above described and other shortcomings of existing bioprocessing systems and their valve assemblies. SUMMARY In accordance with the present invention, the above and other problems were solved by providing a connector apparatus and a sterilized assembly for bioprocessing using the connector apparatus. In addition, a method for implementing a connector apparatus is provided. In one embodiment of the present invention, a connector apparatus includes a coupler and a connector valve having a valve member. In example embodiments, the connector apparatus can be coupled to bioprocessing equipment and a media source to allow flow therebetween. In example embodiments, the connector apparatus can be used once or multiple times to allow flow between bioprocessing equipment and a media source. An advantage of the present invention is that the employment of a connector apparatus can greatly simplify the parts of a coupling mechanism in a bioprocessing system. Further, it can minimize the need for cumbersome laminar flow hoods and complex valve assemblies that may use multiple steam traps. Further, multiple exchanges can be accomplished between a piece of bioprocessing equipment and several media sources while maintaining the sterility of the bioprocessing equipment and connector apparatus. These and other various advantages and features are pointed out in the following detailed description. For a better understanding of the disclosed embodiments and their advantages, reference should also be made to the drawings which form a further part hereof, and to accompanying descriptive matter, in which there are illustrated and described specific examples of an apparatus in accordance with the invention. DESCRIPTION OF THE DRAWINGS Referring now to the drawings in which like reference numbers represent corresponding parts throughout: FIG. 1 is a perspective view of one embodiment of a connector apparatus in a closed state in accordance with the principles of the present invention; FIG. 2 is a side view of the connector apparatus of FIG. 1 ; FIG. 3 is an end view of the connector apparatus of FIG. 1 ; FIG. 4 is a top view of the connector apparatus of FIG. 1 ; FIG. 5 is a cross-sectional view taken along line 5 — 5 of the connector apparatus of FIG. 3 ; FIG. 6 is a cross-sectional view of taken along line 6 — 6 of the connector apparatus of FIG. 4 ; FIG. 7 is a perspective view of the connector apparatus of FIG. 1 in an open state; FIG. 8 is a side view of the connector apparatus of FIG. 7 ; FIG. 9 is an end view of the connector apparatus of FIG. 7 ; FIG. 10 is a top view of the connector apparatus of FIG. 7 ; FIG. 11 is a cross-sectional view taken along line 11 — 11 of the connector apparatus of FIG. 9 ; FIG. 12 is a cross-sectional view taken along line 12 — 12 of the connector apparatus of FIG. 10 ; FIG. 13 is a perspective view of one embodiment of a coupler in accordance with the principles of the present invention; FIG. 14 is a side view of the coupler of FIG. 13 ; FIG. 15 is a perspective view of one embodiment of a valve member in accordance with the principles of the present invention; FIG. 16 is a side view of the valve member of FIG. 15 ; FIG. 17 is a cross-sectional view taken along line 17 — 17 of the valve member of FIG. 16 ; FIG. 18 is a perspective view of one embodiment of a connector valve in accordance with the principles of the present invention; FIG. 19 is a top view of the connector valve of FIG. 18 ; FIG. 20 is an end view of the connector valve of FIG. 18 ; FIG. 21 is a cross-sectional view taken along line 21 — 21 of the connector valve of FIG. 20 ; and FIG. 22 is a flow diagram of an embodiment of a method of coupling a media source to a piece of bioprocessing equipment in accordance with the principles of the present invention. In the following description of the illustrated embodiments, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration of the embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized as structural changes may be made without departing from the spirit and scope of the present invention. DETAILED DESCRIPTION Embodiments of the present invention relate to a connector apparatus for coupling a media source to a piece of bioprocessing equipment. Embodiments of the connector apparatus disclosed herein are similar to those disclosed in U.S. patent application Ser. No. 10/097,073, entitled “Connector Apparatus and Method of Coupling a Bioprocessor to a Media Source” and filed on Mar. 12, 2002, the entirety of which is hereby incorporated by reference. Referring now to FIGS. 1–12 , one embodiment of a connector apparatus 50 is illustrated connecting a media source 70 to a piece of bioprocessing equipment 90 . In FIG. 1 , the connector apparatus 50 includes a coupler 20 (see FIGS. 13 and 14 ) and a connector valve 10 (see FIGS. 18–21 ). The connector valve 10 includes a valve member 40 (see FIGS. 15–17 ) disposed therein. As shown in FIG. 1 , the valve member 40 includes an end 112 suitable for attachment to the media source 70 . The end 112 , as depicted in FIG. 1 , is shown as a barbed end for attachment to a media source, such as 70 . However, there may be other interfaces that can be used to achieve the same result. The coupler 20 has an outlet 122 for passage of media and connection to the piece of bioprocessing equipment 90 , such as but not limited to a bioreactor. The outlet 122 , as depicted in FIG. 1 , is shown as a sanitary flange. However, there may be other interfaces that can be used to achieve the same result. Also depicted is a second outlet 124 of coupler 20 for allowing steam passage to a steam trap or a condensate outlet during, for example, sterilization as described below. A sanitary flange similar to that of outlet 122 is disposed at the second outlet 124 . However, it will be appreciated that an O-ring seal also can be used at the second outlet 124 . Referring now to FIGS. 13 and 14 , coupler 20 includes outlets 122 and 124 noted above as well as an opening 250 for receiving the connector valve 10 . Coupler 20 also includes flanges 252 defined by slots running through to the opening 250 , and each flange 252 defines an aperture 22 for receiving tabs 12 of the connector valve 10 , as described further below. As shown more particularly in FIGS. 5 and 6 , the connector valve 10 is disposed within the coupler 20 . Referring now to FIGS. 18–21 , the connector valve 10 defines a passage 260 sized to receive valve member 40 . Tabs 12 on the connector valve 10 engage apertures 22 of the coupler 20 (see FIG. 13 ) and retain the connector valve 10 in place within the coupler 20 . An O-ring seal 14 positioned in slot 262 (see FIGS. 18 , 19 , and 21 ) engages the inner diameter of the connector 20 to seal end 16 of the connector valve 10 with the coupler 20 . Referring now to FIGS. 15–17 , valve member 40 defines a passage 224 from end 112 to end 130 . While end 112 is open and in fluid communication with passage 224 , end 130 is closed. In addition, apertures 220 are formed adjacent end 130 and are in fluid communication with passage 224 . Referring again to FIGS. 5 and 6 , the valve member 40 is disposed within the connector valve 10 . O-ring seals 42 and 44 positioned in slots 272 and 274 (see FIGS. 16 and 17 ) of the valve member 40 engage the inner diameter of the connector valve 10 to seal the outer diameter of the valve member 40 with the connector valve 10 . In the illustrated embodiment, a clip member 13 is held in an aperture 18 formed in the connector valve 10 (see FIGS. 18 and 19 ) and surrounds a portion of the valve member 40 . The clip member 13 can be configured as described in U.S. Pat. No. 5,052,725 to Meyer et al., the entirety of which is hereby incorporated by reference. The clip member 13 functions to maintain the valve member 40 in a fixed longitudinal position with respect to the connector valve 10 . More specifically, the clip member 13 can be actuated to allow longitudinal displacement of the valve member 40 with respect to the connector valve 10 between a closed position ( FIGS. 1–6 ) and an open position ( FIG. 7–12 ). For example, in the closed position as shown in FIGS. 1–6 , a portion 15 of the clip member 13 is positioned in a slot 46 formed in the valve member 40 to retain the valve member 40 in place. The clip member 13 can be actuated by pressing tab portion 17 , which then allows the valve member 40 to be moved longitudinally with respect to the connector valve 10 to an open position. Tab 266 of the connector valve 10 (see FIG. 18 ) functions to bias the clip member 13 into the closed position. With the clip 13 actuated, the valve member 40 can be moved longitudinally by, for example, exerting force on (i.e., pushing) winged portion 49 of the valve member 40 . When the fully open position is reached, portion 15 of the clip member 13 is positioned in a slot 48 formed in the valve member 40 to retain the valve member 40 in place. Likewise, the valve member 40 can be moved back to the closed position by actuating the clip member 13 by pressing tab portion 17 and then moving the valve member 40 longitudinally back to the closed position by, for example, exerting force on (i.e., pulling) the winged portion 49 . When the fully closed position is reached, portion 15 of the clip member 13 is once again positioned in the slot 46 formed in the valve member 40 to retain the valve member 40 in place. As illustrated in the example embodiment, portion 15 of the clip member 13 is angled from a leading to a trailing edge so that the valve member 40 can be moved from the closed to the open position without requiring actuation of the clip member 13 . This is accomplished by the angled surface of the portion 15 functioning as a ramp to allow the clip member 13 to be more easily moved out of slot 46 of the valve member 40 when moved from the closed to the open position (see FIG. 5 ). However, once in the open position, the trailing edge of the portion 15 is fully seated within slot 48 (see FIG. 11 ) so that it is difficult to move the valve member 40 from the open position to the closed position without actuating the clip member 13 . In alternative embodiments, the angle in portion 15 of the clip member 13 can be removed, so that it is difficult to move the valve member 40 from both the closed to the open position and the open to the closed position without actuation of the clip member 13 . Referring to FIGS. 6 and 12 , the valve member 40 is slidingly retained in the connector valve 10 by arms 100 of the connector valve 10 . The arms 100 are moveable radially with respect to the connector valve 10 and include tips 102 that extend beyond the outer diameter of the connector valve 10 that is inserted into the coupler 20 . Therefore, when the valve member 40 is positioned in the coupler 20 , the tips 102 of the arms 100 contact the inner diameter of the coupler 20 and the arms 100 are radially biased inwardly. In such an arrangement, an inner end 104 of each arm 100 is positioned within a slot 106 formed on the valve member 40 . With the inner ends 104 positioned in the slot 106 , the valve member 40 can therefore only move longitudinally between ends 108 and 110 of the slot (see FIGS. 16 and 17 ). Therefore, the valve member 40 cannot be pulled beyond the fully closed position (see FIG. 6 ) because the arms 100 contact the end 110 of the slot. When the valve member 40 is in the closed position as shown in FIG. 6 , material can flow from outlet 122 of the coupler 20 , through passage 120 , into junction 121 , and through passage 222 to outlet 124 (reverse flow is also possible). However, because inner end 16 of the connector valve 10 is sealed by O-ring seal 14 against the coupler 20 and end 130 of the valve member 40 is sealed by O-ring seal 44 against the connector valve 10 , no material can flow into passage 224 and to end 112 of the valve member 40 . Conversely, when the valve member 40 is in the open position as shown in FIG. 12 , end 130 of the valve member 40 has been longitudinally displaced through junction 121 and into passage 222 of the coupler 20 such that O-ring seal 44 engages an inner diameter of the passage 222 of coupler 20 . In addition, O-ring seal 42 now seals the valve member 40 against the connector valve 20 adjacent to the junction 121 such that passage 224 in valve member 40 is fluidly connected to junction 121 through apertures 220 formed in valve member 40 (see FIGS. 15–17 ). In this open configuration for valve member 40 , material can flow from outlet 122 of the coupler 20 , through passage 120 , into junction 121 , through aperture 220 formed in valve member 40 (see FIGS. 15–17 ) and through passage 224 to outlet 112 of the valve member 40 (reverse flow is also possible). However, because end 130 of the valve member 40 is sealed by O-ring seal 44 against the inner diameter of passage 222 of coupler 20 , no material can flow into passage 222 and to end 124 of the coupler 20 . In a like manner, valve member 40 can be longitudinally displaced back into the closed position (see FIG. 6 ) to reestablish fluid communication between passages 120 and 222 , and to foreclose communication with passage 224 of valve member 40 . In example embodiments, the connector apparatus 50 can withstand steam and autoclave conditions. In addition, the connector apparatus 50 can be made of a material such as polycarbonate, or a polysulphone, or a polyphenylsulfide and including other high temperature thermoplastics or materials, which can be injection molded. The media source can be a media bag or other like media vessel. The piece of bioprocessing equipment may be a bioreactor and can include a steam source for sterilization. The dimensions for a bioreactor and media source are specific to the needs of the biomaterial being processed and are further not described here. FIG. 22 illustrates an example flow diagram of a method for coupling a bioreactor with a media source using an example connector apparatus disclosed herein. The method includes, at 901 , providing a connector apparatus, a media source, and a piece of bioprocessing equipment as detailed in the above descriptions. The connector apparatus is then connected to the bioprocessing equipment at 903 . Next, the bioprocessing equipment and the connector apparatus are sterilized at 905 . In one embodiment, the bioprocessing equipment and the coupler are steam sterilized, and outlet 124 of coupler 20 functions as a steam trap or condensate outlet. Next, the media source is coupled to the connector apparatus at 907 , and the media source and connector apparatus are sterilized at 909 using, for example, gamma sterilization. After this sterilization is completed, the entire assembly including the media source, connector apparatus, and piece of bioprocessing equipment are ready for use. Next, the connector apparatus is opened at 911 by moving the valve member 40 from the closed position to the open position as described above. In this position, media can flow from the bioprocessing equipment to the media source, or vice versa. Next, the flow of media between the bioprocessing equipment and the media source can be stopped at 913 by closing the connector apparatus through actuation of the valve member 40 from the open position to the closed position as described above. Once flow has been terminated, the media source can be disconnected from the connector apparatus at 915 . If desired, the connector apparatus can then be reused. For example, the bioprocessing equipment and connector apparatus can be sterilized again at 905 , and a media source can be connected to the connector apparatus and sterilized at 907 and 909 . Next, the connector apparatus can be opened at 911 , allowing media to flow between the bioprocessing equipment and media source. Next, the connector apparatus can be closed at 913 , and the media source can be disconnected at 915 . In this manner, the connector apparatus can be used once or multiple times, as desired. Further, multiple exchanges can be accomplished between a piece of bioprocessing equipment and several media sources while maintaining the sterility of the bioprocessing equipment and connector apparatus. Further, the connector apparatus provides a more convenient and practical way of connecting bioprocessing equipment with a media source. In addition, the connector apparatus provides a versatile means for coupling that can be easily modified to accommodate a range of needs with respect to particular biomaterials processed. Various modifications can be made to the example embodiments disclosed herein. For example, although the coupler 20 and connector valve 10 are illustrated herein as separate pieces, they can also be formed as one integral piece. Having described the embodiments of the present invention, other modifications and equivalents may occur to one skilled in the art. It is intended that such modifications and equivalents shall be included with the scope of the invention.	A connector apparatus designed for use in a bioprocessing assembly, and a method for coupling a piece of bioprocessing equipment to a media source in a sterilized environment. The connector apparatus includes a coupler including an end and at least one outlet, and a connector valve connectable at a first end to a fluid source, the connector valve including a valve member, the valve member being partially disposed within the coupler. The connector apparatus further includes a flow passage being actuatable from a closed configuration to an open configuration when the coupler and the connector valve are engaged, as well as being actuatable from an open configuration to a closed configuration. A clip member attached to the coupler allows the valve member to be moved from the closed configuration to the open configuration, and from the open configuration to the closed configuration.	8
FIELD OF THE INVENTION The present invention relates generally to cell relay systems and, more particularly, to a system that selectively controls the discarding of information. BACKGROUND OF THE INVENTION Cell relay systems, such as asynchronous transfer mode (ATM) systems, transmit data over a network as a plurality of fixed-length cells. The individual transmissions typically include one or more cells that constitute a portion of variable-length packets used by end systems or applications. Before transmission, a source station segments a packet into one or more cells and then transmits the cells. A destination station, after receiving all of the cells associated with the packet, reassembles the cells and provides them to the end system or application. If a portion of the packet (i.e., one or more cells) becomes corrupt or dropped during transmission, the entire packet becomes corrupt. The end system or application typically has no use for the remaining cells of a corrupt packet. In an ATM system that uses ATM adaption layer 5 (AAL5), the system establishes a particular route or “virtual circuit” over which the cells travel between the source station and the destination station. The source station transmits the cells over the virtual circuit in order and the cells arrive at the destination station in the same order. Sometimes cells from other packets traveling over a different, intersecting virtual circuit interleave with the cells and, thus, alter their time but not their order of arrival at the destination station. The destination station extracts the cells based on virtual circuit information included in the cells before it reassembles them into the associated packets. Problems arise when the network becomes congested and intermediate switches contain insufficient buffer capacity to handle incoming traffic. Conventional switches discard incoming cells when their buffers are full. Then, when sufficient buffer space becomes available, they store incoming cells again. Accordingly, the switches may discard a portion of a packet and retain the preceding and succeeding portions, or fragments of the packet. These essentially useless packet fragments continue to travel over the network, consuming network resources. In addition, because conventional switches store useless packet fragments in their buffers, this valuable buffer space becomes unavailable to the cells of complete or “good” packets. In other words, the switches discard good cells while also storing useless packet fragments. Typically, packets with discarded good cells must be retransmitted, adding to the network congestion. Therefore, a need exists for a discard scheme that improves packet throughput during periods of network congestion and improves resource allocation among source and destination units when network congestion is present on one cell routing path, but less prevalent along another path. SUMMARY OF THE INVENTION Systems and methods consistent with the present invention address this need by providing a cell discard scheme that determines whether to discard a cell of a packet based on the ability of a buffer to store the entire packet. In accordance with the purpose of the invention as embodied and broadly described herein, a system consistent with the present invention includes a cell relay switch having an output port including a queuing buffer, a controller and an output processor. The output port receives a plurality of cells of different packets from multiple sources. The output processor transmits cells to multiple destinations. Upon receiving the cells, the queuing buffer temporarily stores them before transmission by the output processor. The controller controls the storing of the received cells in the queuing buffer by determining a total number of the cells in the packet, a rate at which the packets are received, and a number of cells to be received for other packets. The controller further decides whether the buffer contains sufficient space to store the received cells based on the total number of cells in the packet and the number of cells to be received for the different packets, allows storage of the received cells when the buffer contains sufficient space, and discards the received cells when the buffer contains insufficient space. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, explain the principles of the invention. In the drawings, FIG. 1 is a block diagram of an exemplary cell relay network consistent with this invention; FIG. 2 is an exemplary diagram of a packet transmitted in the network of FIG. 1; FIGS. 3A and 3B are exemplary diagrams of components of a cell included in the packet of FIG. 2; FIG. 4 is a block diagram of an output port residing within the exemplary cell relay switch in the network of FIG. 1; FIGS. 5A and 5B are flowcharts of cell discard processing consistent with the present invention; and FIG. 6 is a graph of buffer capacity as a function of time. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following detailed description of the invention refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. Also, the following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims. Systems and methods consistent with the present invention provide a cell discard scheme for an output port within a cell relay switch. The output port either guarantees delivery of all of the cells of a packet or drops all the cells beginning with the first one. The output port decides whether to store an incoming cell based on whether the buffer has sufficient capacity to store all of the cells of the associated packet. Exemplary Cell Relay System FIG. 1 is a simplified block diagram of a cell relay system 100 . The system 100 includes a number of source stations 110 and 115 and a number of destination stations 120 and 125 connected through switch 130 by virtual circuits 140 and 145 . The source stations 110 and 115 and destination stations 120 and 125 include computers, such as IBM-compatible computers, workstations, or even “dumb” terminals. While only two pairs of source stations 110 and 115 and destination stations 120 and 125 are shown in FIG. 1, those skilled in the art will recognize that systems and method consistent with the present invention may be used in a network with any number of source and destination stations and any number of switches. Switch 130 is a cell relay switch that receives multiple cell streams from any source station 110 or 115 and transmits the cells to any destination station 120 or 125 . Switch 130 receives and transmits the cells via the virtual circuit 140 or 145 . Virtual circuit 140 and 145 are routes established through system 100 by which source stations 110 and 115 transmit the cells to destination stations 120 and 125 . Virtual circuit 140 and 145 transmit data at a peak rate (R). When a source station 110 communicates with a destination station 120 or 125 , for example, source station 110 segments a packet of information into a number of cells. FIG. 2 is a diagram of a packet 200 . Packet 200 is a variable-length packet, such as an Internet Protocol (IP) packet. Source station 110 divides the variable-length packet 200 into several cells 210 of fixed length. FIGS. 3A and 3B are exemplary diagrams of components of a cell 210 of FIG. 2 . The cell 210 includes a payload 310 and a header 320 . Payload 310 includes data of fixed-length. FIG. 3B shows the fields included in header 320 for, an ATM-formatted cell. Header 320 includes a generic flow control (GFC) field 321 , a virtual path identifier (VPI) field 322 , a virtual circuit identifier (VCI) field 323 , a payload type identifier (PTI) field 324 , a cell loss priority (CLP) field 325 , and a checksum (CRC) field 326 . The ATM cell is depicted for exemplary purposes only and the present invention may operate on any type of cell format. Exemplary Output Port FIG. 4 is an exemplary block diagram of an output port 400 contained within cell relay switch 130 shown in FIG. 1 . Output port 400 includes a queuing buffer 410 , a controller 420 , and an output processor 430 . Queuing buffer 410 receives the packets transmitted by various source stations 110 . Output processor 430 relays the packets of cells to a particular destination station 120 via a fiber link 432 or similar communication link. Queuing buffer 410 temporarily stores the cells received by output port 400 before transmission by output processor 430 . Controller 420 includes a standard device, such as a processor, that controls the operation of buffer 410 and output processor 430 . Controller 420 executes software to determine which of the received cells will be discarded and which cells will be stored in queuing buffer 410 for transmission by the output processor 430 . Controller 420 bases its determination on factors that optimize use of buffer 410 . Output processor 430 provides the processing necessary to transmit the selected cells to the destination station 120 . As described in greater detail below, this determination is based upon the present occupancy of buffer 410 , the size of the packet, and the rate at which the packet is received. Exemplary Cell Discard Processing FIGS. 5A and 5B are flowcharts of cell discard processing consistent with the present invention. The processing begins when an output port 400 receives a cell of an incoming packet over a virtual circuit at queuing buffer 410 [step 505 ]. Each packet has an identifier such as a Virtual Circuit Identifier (VCI), for example, to identify the virtual circuit over which it is carried. Controller 420 processes the incoming cell to determine whether it is the first cell of the packet [step 510 ]. Controller 420 might make this determination from information provided in the header 320 (FIG. 3B) of the ATM cell, or from information contained within payload 310 . If controller 420 determines that the cell is the first cell, controller 420 next determines the length of the packet L x [step 515 ]. This determination may be made from information within cell header 320 or alternatively, from data within the payload of the first cell. Controller 420 also determines the peak arrival rate of the cells R x of this packet [step 520 ]. The peak rate information is stored within the switch during the initial virtual circuit setup. Next, controller 420 calculates the projected maximum buffer occupancy (B m ) of output port 400 if the packet was to be accepted [step 525 ]. To make this determination, controller 420 uses the current condition of output port 400 and the time needed to complete the receipt of the pending packet (L x , R x ). In accordance with the present invention, the current conditions of output port 400 may be based upon the current buffer occupancy B c , the rate at which output processor 430 processes (outputs) the cells from the buffer, and the number of cells in the current packet that have yet to arrive. To simplify the calculations, the rates at which the cells are received are normalized to correspond to the processing rate of output processor 430 . If the peak arrival rate of a particular virtual circuit is half the rate of output processor 430 , for example, then the normalized rate would be 0.5. Controller 420 determines the number of cells yet to be received from the total length of the packet. To accomplish this determination, controller 420 contains a mechanism to determine the number of remaining cells that have yet to arrive at buffer 410 . For example, the cell may carry a decrementing counter field that explicitly conveys the number of remaining cells. To implement this feature, the system may use the header CRC field 326 (FIG. 3 B), for example, as a counter to convey the length of the packet in terms of cells. This limits the length of the packet, however, to 256 cells or 12,288 bytes. Alternatively, controller 420 might contain a counter that decrements when a cell belonging to the same packet and identified with the same VCI has been stored in buffer 410 . If there are currently a total number of N packets accepted by output port 400 , then the peak arrival rate of these N packets will be R i , where i=1, 2, . . . N. The number of cells of these N packets that have yet to arrive at buffer 410 will be L i , where i=1, 2, . . . N. Given the number of remaining cells and the rate at which cells will be received from a given virtual circuit, controller 420 arranges the packets according to completion time such that L 1 /R 1 ≦L 2 /R 2 ≦ . . . ≦L N /R N . Once this ordering is established, controller 420 determine's the point at which the buffer occupancy reaches its maximum. FIG. 6 is a graph of buffer occupancy (B) as a function of time (T). The graph shows that the buffer occupancy begins as an increasing function with decreased rate. After the maximum point is reached, denoted (T m , B m ), the buffer occupancy becomes a decreasing function with an increasing rate. Initially, the aggregate arrival rate of all the packets is greater than the rate at which the output processor can process the cells in buffer 410 . This aggregate arrival rate decreases when all the cells of a packet have arrived at buffer 410 , and the packet's contribution to the aggregate arrival rate becomes zero. According to the preferred embodiment, as more and more packets are completed, the aggregate rate will continue to decrease. The maximum point (T m , B m ) is reached when the aggregate arrival rate becomes smaller than the processing rate of output processor 430 . To determine the time at which the maximum buffer occupancy (T m , B m ) is reached, controller 420 must determine the point at which the aggregate arrival rate becomes less than 1. Controller 420 adds the peak rates (R 1 , R 2 , . . . R N ) to determine the point at which the combination of peak rates becomes smaller than 1: ( R 1 +R 2 + . . . +R N )>1 ( R 1 +R 3 + . . . +R N )>1 . . . ( R j +R j+1 + . . . +R N )>1 ( R j+1 +R j+2 + . . . +R N )>1 . . . ( R N )>1 If the rate R j , for example, increases the aggregate arrival rate from ≦1 to greater than 1, then the time at which buffer 410 reached maximum occupancy is T m =L j /R j and the maximum occupancy is B m =B c +L 1 +L 2 + . . . +L j +( R j+1 + . . . +R N )* T m −(1 T m ) In this case, B c refers to the current buffer occupancy; L 1 +L 2 + . . . L j are the remaining cells of the packets that will be completed by the time T m ; (R j+1 + . . . +R N )T m refers to the number cells of packets that will not be completed by time T m ; and (1*T m ) refers to the total number of cells that will be processed by T m . If the aggregate arrival rate is always less than 1, then controller 420 simply uses R N as R j in the calculation. After determining the current buffer occupancy, controller 420 uses the information including the current conditions of output port 400 to determine whether to accept the newly arrived packet with length L x and peak rate R x . Specifically, controller 420 inserts the new packet [L x , R x ] into the collection of accepted packets [L i , R j ], where i=1, 2, . . . , N, and recalculates the new maximum buffer capacity B m if the new packet were to be accepted. Based upon the new maximum value, B m , controller 420 must determine whether to accept the incoming cell of the packet based on whether buffer 410 contains sufficient remaining capacity to store the new packet [step 530 ]. If the new B m is greater than the physical capacity of buffer 410 , then the packet must be discarded because buffer 410 will not have the storage capacity to store the entire packet. If, on the other hand, the new B m is smaller than the physical capacity of buffer 410 , then the cell can be accepted. If the cell is accepted, controller 420 allows it to be stored in buffer 410 [step 535 ]. In accepting the new cell, controller 420 logs the VCI x of the new packet, such that the length, L x , and the rate, R x of the new packet may be used in future calculation. If the new B m is larger than B T (i.e., the maximum capacity), then the full cell packet cannot be accepted for storage and is therefore discarded [step 540 ]. Upon discarding the cell, controller 420 also logs that the packet identified with VCI x , for example, was discarded and the L x and R x of the discarded packet will not be included in future calculations. Returning to step 510 , if the received cell is not the first cell of a packet, then controller 420 determines whether the first cell of the packet was discarded or accepted based upon the VCI of the cell [step 545 ] (FIG. 5 B). Controller 420 might make this determination based on the information stored in the header of the cell, such as the virtual circuit identifier (VCI) field 323 (FIG. 3 B). The decision could also be made from information included within the body or payload of the cell. If controller 420 had accepted the first cell, then it stores the new cell in buffer 410 [step 550 ]. If, on the other hand, controller 420 discarded the first cell, then it also discards this new cell [step 555 ]. Regardless of whether controller 420 stores or discards the cell, it prepares itself for receipt of the next cell by returning to step 505 of FIG. 5 A. If the cell is stored, then all the remaining cells of the accepted packet are subsequently stored. The systems and methods consistent with the present invention optimize packet transmission through a cell relay system by guaranteeing that if one cell of a packet is accepted, then all cells of the packet will also be accepted. The foregoing description of preferred embodiments of the present invention provides illustration and description, but is not intended to be exhaustive or to limit the invention to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The scope of the invention is defined by the claims and their equivalents. For example, the foregoing description assumed that all cells belonging to the same IP packet arrive at the output port at the same maximum peak rate of the corresponding virtual circuit. In some ATM systems, however, the source station enters into a negotiated traffic contract with the system for packets that it transmits. In this case, the arrival rate depends on traffic shaping performed at the source station. In multi-hop relay systems, the system sometimes introduces timing jitter into the cell transmission. The timing jitter prolongs the cell arrival rate.	A cell relay switch includes an output port for transmitting cells to multiple destinations. The output port further includes a queuing buffer, a controller, and an output processor. The buffer receives a plurality of cells of a packet from a source. The buffer temporarily stores the cells before transmission by the output processor. The controller controls the storing of the received cells in the buffer by determining a total number of the cells in the packet and a number of cells to be received from different packets, deciding whether the buffer contains sufficient space to store the received cells based on the total number of cells in the packet, the number of cells to be received from the different packets, and the rates at which cells are received and drained from the buffer. The buffer is commanded by the controller to store the received cells when the buffer contains sufficient space and discard the received cells when the buffer contains insufficient space.	7
BACKGROUND OF THE INVENTION This invention relates to a novel styrylpyridinium salt or a novel styrylquinolinium salt containing an acetal group useful for the preparation of a water-soluble highly photosensitive resin and to a method for the manufacture of the salt. Water-soluble photosensitive resins are used in low-pollution type photoresists and photomilling materials. Recently, these photosensitive resins have come to receive attention for their usefulness as immobilizing carriers for enzymes and other bioactive substances. As a photosensitive high-molecular compound suitable for such new uses, the inventors earlier developed a polymer possessing a stilbazolium residue [Refer to Ichimura & Watanabe: Chem., Lett., 1289 (1978)]. They continued a study with a view to imparting enhanced water solubility and improved photosensitivity to the polymer possessing the stilbazolium residue. They have, consequently, discovered that a water-soluble highly photosensitive resin can be obtained by using a method for incorporating a stilbazolium group into poly(vinyl alcohol) through the reaction of acetalization (U.S. Application Ser. No. 62,490, dated July 31, 1979). SUMMARY OF THE INVENTION The inventors have devoted a diligent study to the development of a compound possessing a styrylpyridinium group or a styrylquinolinium group suitable for the reaction of acetalization and, consequently, have succeeded in developing a novel nitrogen-containing heterocyclic compound possessing a styryl group and a method for the manufacture of the compound. Specifically, the novel compound of the present invention is a nitrogen-containing heterocyclic compound represented by the general formula: ##STR5## wherein, Y is one member selected from the group consisting of ##STR6## A is one member selected from the group consisting of ##STR7## n is an integer having the value of 1 to 6, X is a strongly acidic anionic residue and, in the substituents Y and A, R 1 is one member selected from the group consisting of an alkyl group, aryl group and aralkyl group, R 2 and R 3 are each an alkyl group, and R 4 is an alkylene group. The nitrogen-containing heterocyclic compound represented by the formula (I) is prepared by the reaction of a benzaldehyde derivative represented by the general formula: ##STR8## and a compound represented by the general formula: Y--CH.sub.3 (III). In the formulas (II) and (III), A and Y have the same meanings as used in the formula (I) above. An object of the present invention is to provide a novel nitrogen-containing heterocyclic compound possessing a styryl group highly suitable for the incorporation of a styrylpyridinium group or a styrylquinolinium group directed to imparting photosensitivity to polymers. Another object of this invention is to provide a method for the manufacture of the nitrogen-containing heterocyclic compound described above. DESCRIPTION OF THE PREFERRED EMBODIMENTS The aldehyde possessing an acetal group, represented by the general formula, ##STR9## (II), and used as the raw material in the method of the present invention is obtained by causing an acetal of the general formula: X'(CH.sub.2).sub.n A (IV) (wherein, X' denotes a halogen atom, alkanesulfonyloxy group or arenesulfonyloxy group, and A and n have the same meanings as described above) to react thermally with hydroxybenzaldehyde under an alkaline condition. The conditions under which the thermal reaction is effectively carried out are as follows. The molar ratio of acetal to hydroxybenzaldehyde is within the range of 1:0.5˜2. The thermal reaction is carried out at temperatures within the range of from 50° to 200° C. for a period of from one to 24 hours. The molar ratio of hydroxybenzaldehyde to alkali in the reaction solution is about 1:1˜1.5. The reaction between the benzaldehyde possessing an acetal group and represented by the general formula (II) which is obtained as described above and the compound represented by the general formula (III) can be advantageously carried out in a polar solvent such as, for example, methanol, ethoxyethyl alcohol or ethanol. Normally this reaction is performed at temperatures within the range of from room temperature to 100° C. for a period of from 30 minutes to 20 hours. In this case, it is advantageous to avoid performing this reaction at excessively high temperatures or for a prolonged period of time. When the reaction temperature is lower or the reaction time shorter than the respective ranges mentioned above, the reaction proceeds very slowly. When the reaction temperature is higher or the reaction time longer than the respective ranges, however, the reaction produces a heavily colored resinous product, with the result that the product is difficult of isolation and purification and the yield of the reaction itself is lowered. In the reaction, it is important that the molar ratio of the compound (II) to the compound (III) should fall within the range of 1:0.5˜1. When the amount of the compound (III) fails to reach the lower limit of the aforementioned range, the amount of the compound (II) which remains unaltered after the reaction is so large as to jeopardize the economy of the reaction. When it exceeds the upper limit of the range, the unaltered portion of the compound (III) mingles into the reaction product at the time that the product is isolated from the reaction mixture, making the purification of the product highly complicated. To accelerate the reaction, there is used a basic catalyst. Aliphatic amines and the acetates thereof are preferably used as the catalyst. Concrete examples of catalysts which are advantageously used for this reaction include pyrrolidine, piperidine, diethylamine and triethylamine. The amount in which the catalyst is added to the reaction system is within the range of from 0.1 to 5 mol% based on the combined amount of the reactants (II) and (III). Practical examples of the residues R 1 , R 2 , R 3 and R 4 involved in the general formulas of the reactants are as follows: R 1 -Methyl, ethyl, propyl, butyl and benzyl R 2 , R 3 -Methyl, ethyl and propyl R 4 -Ethylene, 1,3-propylene and 1,2-propylene Examples of benzaldehyde derivatives possessing an acetal group and represented by the general formula (II) are o-(2,2-dimethoxyethoxy)benzaldehyde, m-(2,2-dimethoxyethoxy)benzaldehyde, p-(2,2-dimethoxyethoxy)benzaldehyde, p-(2,2-diethoxyethoxy)benzaldehyde, p-(3,3-dimethoxypropoxy)benzaldehyde, p-(4,4-diethoxybutoxy)benzaldehyde, p-(5,5-dimethoxypentoxy)benzaldehyde, p-(6,6-dimethoxyhexyloxy)benzaldehyde, m-(2,2-ethylenedioxyethoxy)benzaldehyde, p-(3,3-propylenedioxypropoxy)benzaldehyde and p-(5,5-ethylenedioxypentoxy)benzaldehyde. Concrete examples of the substituent X - in the compound of the aforementioned general formula (III) are halogen ions, sulfuric acid ion, methyl sulfate ion, phosphoric acid ion, methanesulfonate ion, and p-toluenesulfonate ion. Specific examples of the compounds containing such substituents are chlorides, bromides, iodides, methyl sulfates, methanesulfonates and p-toluenesulfonates of pyridinium and quinolium such as 1,2-dimethylpyridinium, 1,4-dimethylpyridinium, 1-ethyl-4-methylpyridinium, 1-butyl-4-methylpyridinium, 1-benzyl-4-methylpyridinium, 1-(2-hydroxyethyl)-2-methylpyridinium, 1-(2-hydroxyethyl)-4-methylpyridinium, 1,2-dimethylquinolinium, 1,4-dimethylquinolinium and 1-ethyl-4-methylquinolinium. The above mentioned quaternary salts may be those incorporating lower alkyl and hydroxy groups having up to about six carbon atoms on condition that the presence thereof does not interfere with the condensation reaction. The nitrogen-containing heterocyclic compound possessing an acetal group and represented by the aforementioned general formula, ##STR10## (I), which is obtained by the method described above is a crystalline substance. This compound, when exposed by itself to light for a long time, undergoes a change presumably originating in photodimerization reaction. It is, therefore, desired to be stored in a place shielded from light of short wavelength. The chemical structure of the novel nitrogen-containing heterocyclic compound represented by the aforementioned general formula (I) has been determined on the basis of the results of elementary analysis, infrared absorption spectrum and ultraviolet absorption spectrum. The nitrogen-containing heterocyclic compound of the present invention which is represented by the aforementioned general formula (I), when allowed to react with poly(vinyl alcohol) or a partially saponified poly(vinyl acetate), efficiently produces a photosensitive resin of a poly(vinyl alcohol) derivative possessing a structural unit of the general formula: ##STR11## (wherein, R 1 , X - and n have the same meanings as described above). Specifically, use of the nitrogen-containing heterocyclic compound possessing an acetal group obtained by the present invention permits a wide choice of the N-substituent and promises easy adaptation of the physical and chemical properties of the photosensitive resin, as the final product, to suit the particular application for which the resin is intended. The production of the aforementioned photosensitive resin can be carried out in water in the presence of an acidic catalyst. The reaction brings about a water-soluble, highly photosensitive resin. Typical photosensitive resins containing the nitrogen-containing heterocyclic compound of the present invention are cited below, with the properties of the resins indicated correspondingly. __________________________________________________________________________Kind of resinmatrix Properties of photo-Poly(vinyl alcohol) sensitive resin(PVA) AmountPolyme-Saponifi- Nitrogen-containing added based Relativerizationcation heterocyclic compound on vinyl sensiti-degreedegree Structure unit of PVA vity__________________________________________________________________________1700 about 87% ##STR12## 0.8 mol % 2.2" " " 1.4 mol % 6.5" " ##STR13## 0.75 mol % 3.7" " " 1.3 mol % 8.5" " ##STR14## 1.1 mol % 10.2" " " 2.1 mol % 30" " ##STR15## 0.53 mol % 7__________________________________________________________________________ Based on the sensitivity (as unity) which is exhibited by a poly(vinyl alcohol) (polymerization degree 1700 and saponification degree about 87%) containing 6 w/w % of ammonium dichromate. The development was invariably made in water. Now, the present invention will be described below specifically with reference to working examples. The first two examples concern the preparation of benzaldehyde derivatives. EXAMPLE 1 In 50 ml of methanol, 50 g of p-hydroxybenzaldehyde and 23 g of potassium hydroxide were dissolved. The resultant solution was distilled under a vacuum to expel the solvent. The residue of the distillation was dried under a vacuum. This dry residue was dissolved by heating in 60 ml of N-methyl pyrrolidone. In the resultant solution, 76.5 g of chloroacetaldehyde dimethyl acetal was heated at 150° C. for 15 hours. The reaction solution was combined with 200 ml of dichloromethane and washed three times with water and was further washed with 100 ml of an aqueous 10% sodium hydroxide solution to recover the unaltered portion of hydroxybenzaldehyde. Next the so-obtained organic phase was washed with water, dried with anhydrous potassium carbonate and distilled to extract N-methyl pyrrolidone, whereafter p-(2,2-dimethoxyethoxy)benzaldehyde was extracted at 135° C./3 mmHg. When the extracts thus obtained were distilled again, there was obtained 34.2 g of a colorless liquid of p-(2,2-dimethoxyethoxy)benzaldehyde at 145° C./3 mmHg. EXAMPLE 2 In 20 ml of 2-ethoxyethyl alcohol, 1.65 g of sodium hydroxide and 4.88 g of m-hydroxybenzaldehyde were dissolved by heating. The resultant solution and 7.4 g of bromoacetaldehyde dimethyl acetal were refluxed for 22 hours. Then, the reaction solution was combined with 50 ml of benzene, washed with water, and further washed with an aqueous sodium hydroxide solution until total disappearance of the unaltered portion of hydroxybenzaldehyde and thereafter dried with anhydrous potassium carbonate. By distilling the resultant aqueous solution, there was obtained 3.6 g of m-(2,2-dimethoxyethoxy)benzaldehyde with a boiling point of 138° C./3 mmHg. When the procedure described above was repeated, except that the m-hydroxybenzaldehyde was replaced with the same amount of o-hydroxybenzaldehyde, there was obtained 3.4 g of o-(2,2-dimethoxyethoxy)benzaldehyde with a boiling point of 147° C./5 mmHg. The following five examples concern the method of this invention for the preparation of the novel nitrogen-containing heterocyclic compound. EXAMPLE 3 In 10 ml of ethanol, 5.4 g of 1,4-dimethyl pyridinium.p-toluene sulfonate and 3.7 g of p-(2,2-dimethoxyethoxy)benzaldehyde were dissolved. The resultant solution, with five drops of piperidine added thereto, was refluxed for 30 minutes. The resultant dark green reaction solution, with acetone added thereto and then ethyl acetate further added thereto, was left to stand. The crystals which deposited during this standing were collected and washed with acetone. Consequently, there was obtained 1.75 g of 1-methyl-4-[p-(2,2-dimethoxyethoxy)-styryl]pyridinium.p-toluene sulfonate with a boiling point of 219°˜226° C. The ultraviolet absorption spectrum of this product in water was 370 nm (ε=3.26×10 4 ). The infrared absorption spectrum (KBr) showed peaks at 1620, 1600, 1512, 1470, 1260, 1220, 1180, 1140, 1120, 1075, 1030, 1008, 975, 832, 815 and 675 cm -1 . The yield was 32%. EXAMPLE 4 In 6 ml of methanol, 1.50 g of 1,2-dimethylpyridinium iodide and 1.50 g of o-(2,2-dimethoxyethoxy)benzaldehyde. The resultant solution, with two drops of piperidine added thereto, was refluxed for five hours and then left to stand and cool off. The crystals which deposited consequently were collected and thoroughly washed with acetone. Consequently, there was obtained 2.36 g of 1-methyl-2-[o-(2,2-dimethoxyethoxy)-styryl]pyridinium iodide which melted at 169°˜173° C. This product showed the highest absorption at 353 nm (ε=1.78×10 4 ). The infrared absorption spectrum (KBr) showed peaks at 1630, 1610, 1595, 1567, 1515, 1500, 1450, 1280, 1248, 1130, 1065, 971, 780, 760 and 750 cm -1 . The yield was 87%. EXAMPLE 5 In 6 ml of methanol, 1.50 g of 1,2-dimethyl pyridinium iodide and 1.50 g of m-(2,2-dimethoxyethoxy)-benzaldehyde were dissolved. The resultant solution, with two drops of piperidine added thereto, was refluxed for five hours and thereafter cooled off. Consequently, crystals were deposited. When the crystals were collected and washed thoroughly with acetone, there was obtained 2.34 g of 1-methyl-2-[m-(2,2-dimethoxyethoxy)-styryl]pyridinium iodide. In water, this product showed the highest absorption at 336 nm (ε=2.13×10 4 ). The infrared absorption spectrum (KBr) showed peaks at 1620, 1600, 1580, 1268, 1137, 1068, 965, 840, 772 and 680 cm -1 . The yield was 86%. EXAMPLE 6 In 50 ml of methanol, 12.7 g of 1,2-dimethylpyridinium iodide and 11.96 g of p-(2,2-dimethoxyethoxy)benzaldehyde were dissolved. The resultant solution, with 1 ml of piperidine added thereto, was refluxed for five hours. The solution was left to cool and the crystals which consequently deposited in the solution were collected through filtration and thoroughly washed with acetone. Consequently, there was obtained 16.30 g of 1-methyl-2[p-(2,2-dimethoxyethoxy)-styryl]pyridinium iodide. In water, this product showed the highest absorption at 360 nm (ε=2.67×10 4 ). The infrared absorption spectrum (KBr) of the product showed peaks at 1630, 1615, 1595, 1568, 1512, 1450, 1298, 1260, 1180, 1140, 1073, 965, 862, 821 and 776 cm -1 . The yield was 67%. EXAMPLE 7 In 20 ml of methanol, 4.28 g of 1,2-dimethylquinolinium iodide and 3.47 g of p-(2,2-dimethoxyethoxy)benzaldehyde were dissolved. The resultant solution, with 0.3 ml of piperidine added thereto, was refluxed for seven hours. The solution was left to cool. The crystals which consequently deposited were collected through filtration and then washed thoroughly with acetone. Consequently, there was obtained 5.03 g of 1-methyl-2-[p-(2,2-dimethoxyethoxy)-styryl]quinolinium iodide which boiled at 209°˜212° C. This product in water showed absorption bands (λ max ) at 224, 255, 307 and 399 nm. The infrared absorption spectrum (KBr) showed peaks at 1610, 1590, 1572, 1516, 1240, 1180, 1130, 1068, 985, 830, 780 and 760 cm -1 .	A novel compound represented by the general formula: ##STR1## [wherein, A is one member selected from the group consisting of ##STR2## (where R 2 and R 3 are each an alkyl group and R 4 is an alkylene group), Y is one member selected from the group consisting of ##STR3## (where R 1 is one member selected from the class consisting of alkyl group, aryl group and aralkyl group)] is obtained by causing a compound of the general formula: ##STR4## (wherein, A and n have the same meaning as described above) to react with a compound of the general formula: Y--CH.sub.3 (wherein, Y has the same meaning as described above).	2
BACKGROUND OF THE INVENTION The present invention relates to edible protein products derived from fungal mycelial fibers obtained from a fermenter. When such a material, particularly if the ribonucleic acid coated thereof has been reduced, is mechanically worked and then directly air dried, it becomes very hard and tough-textured. Similarly, products made from the material by reduction of nucleic acid content and direct air drying also have an undesirable texture. SUMMARY OF THE INVENTION The present invention relates to a gas entrappment and drying process. The process involves foaming a fungal mycelial fibrous fermenter product, filtering the slurry, and oven drying the foamed filter cake. The process can product a variety of products which can either resemble various meats in texture or can be similar to snack foods such as cheese puffs. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of one form of the foaming apparatus used in the present invention. FIG. 2 is a view of the sliced foamed filter cake of the present invention. FIG. 3 is one example of filter cake processed to give meat-like texture. DETAILED DESCRIPTION The starting material for use in the present invention is generally prepared by fermentation of a nontoxic microfungus on an assimilable carbohydrate. The resultant product has a substantial protein content and is useful as food for both humans and animals. Various microfungi may be used to prepare the starting material. The preferred microfungus is Fusarium graminearum Schwabe deposited with the Commonwealth Mycological Institute and the American Type Culture Collection (A.T.C.C.) and assigned the numbers I.M.I. 145,425 and A.T.C.C. 20334. Suitable reisolates of this microfungus also deposited with the Commonwealth Mycological Institute (I.M.I.) and the American Type Culture Collection include I.M.I. 154,209, A.T.C.C. 20,329; I.M.I. 154,210, A.T.C.C. 20,333; I.M.I. 154,221, A.T.C.C. 20,330; I.M.I. 154,212, and I.M.I. 154,213, A.T.C.C. 20,322. Other suitable nontoxic microfungi include but are not limited to Fusarium oxysporum (I.M.I. 154,214, A.T.C.C. 20,328), Fusarium solani (I.M.I. 154,217, A.T.C.C. 20,327), and Penicillium notatum chrysogenum (I.M.I. 142,383; I.M.I. 142,384; I.M.I. 142,385; I.M.I. 142,386), with the numbers of strains thereof which have been deposited with the Commonwealth Mycological Institute or American Type Culture Collection given in parenthesis. A typical preparation of the starting material is as follows: A continuous 8-liter fermenter is sterilized and continuously charged with a sterile medium consisting of ______________________________________ g per 100 liters______________________________________MgSO.sub.4 40.5ZnSO.sub.4 . 7H.sub.2 O 0.83CuSO.sub.4 . 5H.sub.2 O 0.167MnSO.sub.4 . 1H.sub.2 O 0.63FeSO.sub.4 . 7H.sub.2 O 0.83K.sub.2 SO.sub.4 . 10.0(NH.sub.4).sub.2 SO.sub.4 144.0NaMoO.sub.4 2H.sub.2 O 0.083CoCl.sub.2 . 6H.sub.2 O 0.17NaCl 10.0CaCl.sub.2 8.0KH.sub.2 PO.sub.4 379.0Biotin 0.0006Dextrose . H.sub.2 O 8,000.0Ammonium citrate 4.0Boric acid 0.05Water to 100 liters______________________________________ The rate of charging the sterile medium is 1.18 liters per hour. The medium in the fermenter is inoculated with a spore suspension of the organism or organisms indicated above. The fermenter is stirred with a 6-bladed disc turbine operated at 850 rpm. Air is flowed through the fermenter at a rate of 3.6 liters per minute. Additional oxygen flow is 2.0 liters per minute. The fermenter temperature is 29.2° C, and the pH is 4.8. Ammonia is added to control the pH and provide additional mycelial nutrient. The fermenter productivity is 5.4 grams per liter hour. The product fungal mycellium is continuously drawn off the fermenter, and collected in a product receiver which is held at 8° C. After steady operation is achieved the pooled product for 10 hours operation is then harvested. Sufficient filter cake to give the concentration indicated under cell weight percent in slurry in Tables 2 and 3 is suspended in 8.0 liters of filtrate which has been preheated to 72° C and which is adjusted with NaOH to pH 6. Addition of the cake decreases the temperature, and the slurry is maintained at 64° C for twenty minutes. This treatment serves to reduce the nucleic acid content of the filter cake so that higher levels of ingestion of the material by humans is possible. This step also serves to rovide the slurry with an agent which has not been positively identified, which serves as a foam stabilizer. If the slurry is filtered and washed with fresh water at this point the foam stabilization will be reduced. The slurry is aerated with stirring adequate to generate small bubbles, but insufficient to break hyphal fibers. The slurry with entrapped air is then partially dewatered to give 20 to 30% solids. At this point the material comprises an entangled mass of limp flexible mycelial filaments with entrapped flattened air bubbles. It is an open network with fibers in random orientation except in regions where they have been drawn into some order by mechanical work. Since the fibers are flexible, interfilament contacts are frequent and involve relatively large areas of surface contact. Referring now to FIG. 1 the mass of wet fungal mycelial RNA reduced fibers 11 is placed in container 12. Flat bladed turbine 13 mounted in foraminous housing 14 is driven by motor 15. In the Examples the container used is a 4-liter cylindrical container containing 3 liters of slurry, the agitator is a Silverson mixer, about 50 mm in diameter, has 6 blades, is operated at about 600 rpm for 1 minute, and the holes in the foraminous housing are about 3 mm in diameter. Tube 16 is connected to means not shown adapted to feed a predetermined amount of gas such as air to the turbine which enables the gas entrappment in the fungal mycelial fibrous matrix. The amount of gas added generally will be enough to provide a foam density of rom 2 to 8 milliliters of gas per gram of solids (solids as used herein are calculated as dry hyphal weight). With foam densities below about 2 ml of gas per gram of solids the product after air drying and rehydration is tough and similar to cardboard in texture. Foam densities above about 8 ml of gas per gram of solids result in products after drying and rehydration which have poor strength and integrity. The preferred density for producing meat-like products is from 3 to 4 ml of gas per gram of solids. For producing snack foods similar to chesse puffs foam densities of from 5 to 6 ml of ga per gram of solids are preferred. The speed at which the turbine is driven is dependent on the size and design of the turbine. The speed should no be so high that significant breakage of the fungal hyphae occurs but must be fast enough to shear the gas into fine bubbles. Coarse bubbles tend to escape from the foam and further result in a product having a somewhat coarser structure than is preferred. Generally, 90% of the bubbles should be from below 3 mm in diameter. Generally, the foam is stable from 30 minutes to one hour after which time the foamed hyphal mass tends to rise appreciably leaving clear liquid at the bottom of the vessel. If this occurs restirring may be done if desired but is not necessary. Foam stability is largely dependent on the average hyphal length of the product. Preferably at least 25% of the hyphae will be longer than 0.5 mm. With less than 10% of hyphae longer than 0.5 mm foam stability is impracticably short and the product is poor. It is not important whether the short hyphae represent an environmental form of the long fibers or a genetic variant so long as the proportion of long hyphae is adequate. The temperature at which the foaming takes place is not critical and 0° C to 100° C can be used. From 15° C to 70° C is the preferred range. Binders such as gluten can be added to the slurry prior to foaming but are not necessary. Generally the foam will contain from 1 to 6 weight percent solids (dry hyphae basis). The foam is then filtered to reduce its moisture content. The technique used to filter the foam is not critical. If average hyphal length is long, generally vacuum filtration is used. Generally, the thickness of the cake being filtered will be from 3 to 20 mm (optimum 6-12 mm). There should be from 0.1 to 0.9 atm pressure drop across the filter cake. Below about 0.1 atm pressure drop the time needed becomes inordinately long. Above about 0.9 atm pressure drop there is a tendency to collapse the foam structure. The filtration step serves to reduce the moisture content of the filter cake to from 18 to 34 weight percent, while retaining almost all of the hyphae and air. In the Examples the filtration is done on a Buckner funnel on filter paper using a 1/2 atm pressure drop; however, screens can be used. A pressure head on the upstream side of the filter cake can be used so that when the pressure is rapidly released after filtration some reexpansion can be achieved. In a preferred aspect of the invention as shown in FIG. 2 the filter cake 21 is sliced in a generally perpendicular direction into strips 22. The strips generally are from 6 to 12 mm in thickness and as wide as the filer cake. The strips are then reassembled as shown in FIG. 3 so that the axis of adjoining strips are at 45° to 90° to each other with respect to their original orientation and the mass compacted and lengthened as by rolling or squeezing, after which slices can be made. The resulting product has planes or weakness more nearly like that of meat than is the case when the untreated filter cake is simply dried. Alternatively, the filter cake can be rolled up on itself, compacted, and sliced or can be extruded through a mesh, recompacted, and sliced. The filter cake is now dried. Generally, the drying is done at 50° C to 90° C is an air oven. The drying serves to reduce the moisture content of the product to below 5 weight percent with about 3 weight percent moisture being preferred. The drying serves to improve the shelf life of the product. The dried product can be rehydrated to absorb from 1 to 5 and preferably 1.5 to 3.0 times its weight of water. After squeezing and blotting the water content decreases to a maximum of abou twice the solids content. In contrast an unfoamed filter cake when dried in an air oven will only take up from 0.2 to 0.5 times the solid's weight of water. Alternately the compacted, foamed log of material can be partly dried before slicing to give an improved surface appearance, then the slices dried completely, or the product can be dried as a log and then sliced after rehydration. EXAMPLE 1 A mycelial slurry of Fusarium graminearum Schwabe I.M.I. 145,425, grown and treated as described above to reduce the nucleic acid content, and containing 31.4 g dry weight per liter, was gassed with N 2 at about 4 ml N 2 per gram dry weight, filtered, washed with 0.6 bed volume distilled water, sliced, and dried in a 60° hot air oven for 16 hours. Another aliquot of the same slurry was similarly treated, except that it was not gassed. Pieces of the dried filter cakes were rehydrated by either heating 10 minutes in 90° C water or by autoclaving at 18 psi for 5 minutes in water, then blotted, weighed, squeeze blotted between 3 layers of paper towels and reweighed. Alpha-amino nitrogen 72 mg/g; RNA 26 mg/g. TABLE 1______________________________________ Ratio of hydrated/dry squeezeExample Sample Rehydration blotted blotted Comments______________________________________1-1 Control hot water .60 .56 woody1-2 autoclaved .94 .84 woody1-3 Aerated hot water 1.56 1.22 resilient1-4 autoclaved 2.90 1.65 resilient______________________________________ EXAMPLE 2 A mycelial slurry of Fusarium graminearum Schwabe I.M.I. 145 425 was grown in a 1300 l continuous fermenter, and treated as described above to reduce the nucleic acid content. The fermenter medium differed in using process water, containing 3.6 fold as much calcium, and using potato starch hydrolysate in place of pure glucose as substrate in the medium reported above. Some of the samples were filtered and resuspended in water before foaming, other samples had gluten added prior to foaming, some samples were filtered without air foaming as controls. Sample slurries were tested at varied cell concentrations and varied ratios of air to cell mass. Product filter cakes were sliced and dried in a hot air oven; weighed pieces were rehydrated in boiling water, squeeze blotted, and reweighed as described above to determine the ratio of water to dry weight held by the rehydrated products. Data is shown in Table 2. TABLE 2__________________________________________________________________________ RNA- Reduction Gluten as Ml Air in Cell Weight RehydrationSample Solubles Percent of Slurry Per Percent Oven Air Dry Water/Dry Weight Comments onCode Present Dry Weight Dry Weight in Slurry ° C Hours 10'Boil 30'Boil Rehydrated__________________________________________________________________________ Samples2-1 Yes 10 None 6 60 15 0.3 0.5 very tough & hard2-2 Yes 10 0.6 6 60 15 0.6 very tough; hard2-3 Yes 10 1.2 6 60 15 0.8 tough; slight resilience2-4 Yes 11 2.4 6 60 15 1.5 resilient-firm2-5 Yes 11 4.8 6 60 15 2.3 resilient-weak2-6 Yes 5 ca 4 6 50 15 1.0 1.4 resilient-firm2-7 Yes None 2.5 6 60 15 1.0 semi-resilient2-8 Yes None ca 4 5 50 15 1.2 (est 1.5) resilient-firm2-9 No 5 ca 4 9 50 or 15 0.5 (est 0.8) tough; hard; 70 slight__________________________________________________________________________ resilience EXAMPLE 3 A mycelial slurry of Fusarium graminearum Schwabe I.M.I. 145,425 was grown as described above for Example 1, except stir rate was 500 rpm, air flow 11 l/minute, no oxygen flow, growth rate 0.14 hr -1 , productivity 3 g/l/hr, pH 5.3. Product was treated to reduce nucleic acid as described above, then aliquots of slurry were adjusted to different cell mass levels, aerated with different ratios of air to cell mass during agitation, filtered, washed with 1 bed volume of water, and sliced as described in Example 1. Part ofthe filter cake was dried directly as slices for 16 hours in a 60° C hot air oven. Part of the filter cake slices were aligned with random rotation directions to randomize the planes of weakness established during filtration, recompacted into a "log" with about two-fold radial compression and corresponding linear extension, leaving a "log" diameter of about 3 to 4 inches. Part of the "log" was sliced at an angle, giving slices 1/4 to 1/2 inch thick, and the remainder left as a large chunk. Slices and chunks were also dried in a hot air oven as described above. Weighed samples of strip, slice, and chunk were rehydrated by immersion in water during 10 minute autoclaving at 18 psi steam pressure, and the rehydrated products squeeze blotted between layers of paper towels. The samples were reweighed and the ratio of water to dry weight calculated, and the products assessed for resilience. Data is shown in Table 3. TABLE 3__________________________________________________________________________ RehydrationSample Cell Weight Percent Ml. Air in Slurry Water/Dry WeightCode in Slurry Per g Dry Weight Strip Slice Chunk Comments__________________________________________________________________________3-1 24 4.2 2.2 2.1 1.8 resilient-firm3-2 16 4.1 1.9 2.0 1.9 "3-3 8 4.0 2.6 2.1 2.1 resilient-slightly soft3-4 16 8.3 2.8 2.3 2.5 resilient-soft3-5 16 16.8 2.4 2.1 2.0 very soft-collapsed during squeeze blotting3-6 16 0 1.3 1.3 1.1 tough, dense (leathery & woody)__________________________________________________________________________ EXAMPLE 4 Two mycelial slurries of Fusarium graminearum Schwabe I.M.I. 145,425 were grown and nucleic acid reduced as described in Example 2, except that the average hyphal lengths were quite different. One culture ("long") had half of the cell mass in fibers above 0.40 mm long (35% of the mass in hyphae over 0.5 mm long, 10% over 1 mm) while the other culture ("short") had half of the mass in fibers above or below 0.2 mm (<2% above 0.5 mm). When 200 ml of RNA-reduced slurry, 23 g/l cell mass, were passed through a 0.25 mm screen of 910 mm 2 area at a pressure differential of 4 psi, the "long" culture required 41 seconds while the "short" culture required 8 seconds (water required 4.5 seconds). The "short" and "long" RNA-reduced hyphal slurries at ca 23 g/l were aerated at ca 4 ml air/g, filtered, sliced, air dried, weighed, rehydrated by 30 minute boiling, drained, squeeze-blotted and reweighed. The "short" slurry had to be filtered quickly at the end of air blending to prevent air bubbles rising from the slurry; air entrappment in the "long" slurry was stable. TABLE 4______________________________________Sample Rehydration Comments onCode Sample Water/Dry Weight Rehydrated Product______________________________________4-1 "long" 1.6 resilient; did not mash or crumble4-2 "short" 1.6 poorly resilient; mashed and crumbled easily______________________________________	An aqueous suspension of a proteinaceous mass of fungal mycelial fibers is foamed with a gas such as air under shear conditions adequate to break the gas into bubbles small enough to be retained by the suspension but not so vigorous as to destroy the fungal mycelial fibers. The resulting slurry is filtered to remove most of the water while retaining the air. The resulting filter cake retains its foamed structure and can then be further processed if desired and air dried to produce a texturized meat-like product. In a preferred aspect of the invention the filter cake is sliced into strips, recompacted and dried to produce a product closely resembling meat in physical properties.	2
CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of U.S. Provisional Patent Application No. 60/791,333 filed Apr. 12, 2006 and U.S. Provisional Patent Application No. 60/902,986 filed Feb. 23, 2007. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to the field of photo-transistor arrays. [0004] 2. Prior Art [0005] Part of imaging detectors (for example, a computed tomography (CT) scanner detector) is a detector array, which includes a 1-D or 2-D scintillator array that converts x-ray radiation into visible light and an attached 1-D or 2-D photodetector array that matches the above scintillator array. The photodetector array may be in the form of back-illuminated photodiode arrays, employing hundreds to thousands of PIN photodiodes arranged in a regular 1-D or 2-D matrix on a single silicon die. The back-illuminated, PIN photodiode array is a flip-chip die attached to the circuit board via either gold stud bumps with conductive epoxy, or solder bumps. Other flip-chip die attach methods can also be used. The downstream, electronics connects the outputs of PIN photodiodes to the inputs of the pre-amplifiers; each PIN photodiode is normally connected to its own pre-amplifier. Currently photo-detectors for CT scanners do not employ in-pixel amplification architecture; integration of pre-amplifier into each photo-detector pixel may provide certain advantages to the system performance (for example, improved noise performance, power consumption, etc.). [0006] There are many publications describing photodetector arrays that allow the integration of different kinds of photo-receivers with transistors, which perform the function of the initial amplification of the detected signal. Various of these publications describe front-illuminated arrays. Some works present structures with the back-illuminated options. However, these are mainly GaAs-based structures and due to their properties and features of their design cannot be used in the medical imaging applications. Currently available Si-based back-illuminated photodetector arrays, integrated with the front-end electronics to amplify their output, employ mainly CCD and CMOS structures, which do not provide a direct addressing of each pixel of the array. [0007] A significant amount of published work explores the features of the structure and principles of operation of the bipolar and JFET transistors integrated with PIN photodiodes. In the case of bipolar transistor, the integration is performed usually by connecting the NPN transistor base with the anode of PIN photodiode built on an N-type substrate. In the case of the photodiode built on a P-type substrate, the PNP transistor base is connected with the photodiode cathode. [0008] For JFET integrated with PIN photodiode, several different structures were proposed. Those structures employed either the P-channel FET or N-channel FET and may work in either depletion or enhancement mode. The (photo)current integrated amplifiers as well as the (photo)charge integrated amplifiers were realized over the last decades. BRIEF DESCRIPTION OF THE DRAWINGS [0009] FIG. 1 is a cross sectional view of a sample detector array structure. Each pixel of the array consists of the PIN photodiode integrated with the NPN bipolar transistor. 1 is N-type Si substrate; 2 is the anode p+ implant/diffusion; 3 is the cathode n+ uniform implant/diffusion; 4 is n+ isolating walls, not necessarily stretching across the whole die thickness; 10 is the collector n implant/diffusion; 11 is the base P implant/diffusion; 12 is the emitter n+ implant/diffusion; 21 , 22 , and 23 are the metal pads for the anode, cathode/collector, and emitter, respectively; 30 is Si oxide layer. [0010] FIG. 2 is a circuit for a pixel of the sample PIN. photodiode—NPN bipolar transistor photodetector array shown in FIG. 1 . [0011] FIG. 3 is a cross-sectional view of a sample detector array structure. Each pixel of the array consists of the PIN photodiode integrated with JFET. 1 is N-type Si substrate; 2 is the anode p+ implant/diffusion; 3 is the cathode n+ uniform implant/diffusion; 4 is n+ isolating walls, not necessarily stretching across the whole die thickness; 13 and 14 are the source and drain n+ implant/diffusion, respectively; 15 and 16 are the top and bottom gate P-type implant/diffusion, respectively; 12 is the emitter n+ implant/diffusion; 21 , 22 , 24 , and 25 are the metal pads for the anode, cathode/drain, source, and gate, respectively; 30 is Si oxide layer. [0012] FIG. 4 is a circuit for a pixel of the sample PIN photodiode—JFET photodetector array shown in FIG. 3 . The sensing resistor Rs and gate resistor Rg may be external to the structure shown in FIG. 3 . [0013] FIG. 5 is an example of the schematic top view of a single pixel of the phototransistor array with micro-pixel structures. Dashed lines 40 outline the transistor of each micro-pixel. Lines 41 connect cathodes/drains of each JFET micro-pixel (or, alternatively, cathodes/collectors of each bipolar phototransistor micro-pixel) in parallel. Lines 42 connect sources of JFET micro-pixels (or, alternatively, emitters of the bipolar phototransistor micro-pixels) in parallel. [0014] FIG. 6 shows an example of the vertical structure of the JFET phototransistor pixel in accord with the present invention. Each pixel consists of multiple micro-pixels. Each micro-pixel includes a separate anode 2 electrically connected to the bottom gate 16 of JFET, drain 14 , and source 13 . The source pads 24 of all micro-pixels have to be connected in parallel either on chip or on the substrate, to which the chip is attached. The drain/cathode pads 22 of all micro-pixels also have to be connected in parallel. [0015] FIG. 7 is similar to FIG. 6 , though shows multiple micro-pixels with an integrated bipolar transistor in accordance with FIGS. 1 and 2 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0016] The present invention suggests integration of the transistors into the structure of the back-illuminated, Si PIN photodiode array described recently in U.S. Pat. No. U.S. Pat. No. 6,762,473 and “The structure and physical properties of ultra-thin, multi-element Si pin photodiode arrays for medical imaging applications” (B. Tabbert et al., In Medical Imaging 2005: Physics of Medical Imaging, Proceedings of SPIE, 5745 (SPIE Bellingham, Wash., 2005), 1146-1154). The photo-transistor array of the current inventions can be built on a relatively high resistivity Si substrate, similar to the one used for building the back-illuminated, PIN photodiode arrays of U.S. Pat. No. 6,762,473, U.S. Patent Application Publication No. 2003/0209652 and U.S. Pat. No. 6,707,046. The invention describes two options for the photo-transistor arrays: [0017] 1) Bipolar transistor integrated with the PIN photodiode; [0018] 2) JFET integrated with the PIN photodiode. [0019] Note that there are many possible ways of integrating the transistor onto the same Si substrate with the back-illuminated PIN photodiode to build arrays which are useful for imaging applications. Those solutions are not limited to the ones presented in the current description but will use similar principles. I. Bipolar Transistor—PIN Photodiode Back-Illuminated Array. [0020] The structure of the array elements built on a high-resistivity Si wafer is shown in FIG. 1 . The structure may preserve the isolation diffusion walls 4 and deep active area anode diffusion 2 described in U.S. Pat. No. 6,762,473. However, the active area diffusion may not necessarily be deep—the shallow active area diffusion is also considered as an embodiment of the invention. The same is valid for the isolation diffusion between adjacent cells—this diffusion may be shallow and may not penetrate through the whole die. The features of the PIN photodiode array structure of FIG. 1 are integrated with the bipolar transistor. The base of the bipolar transistor 11 is electrically connected to the photodiode anode 2 by being overlapping diffusions of the same material type (P-type for the NPN transistor illustrated). The collector 10 , formed of the same material type as the substrate 1 , is common with the photodiode cathode 3 , and the N+ isolation 4 , all being overlapping diffusions of the same material type (N-type in the illustration). The emitter 12 is the photo-transistor output and provides connections to the downstream electronics. A possible circuit schematic for the structure shown in FIG. 1 is presented in FIG. 2 for the N-type Si substrate and NPN bipolar transistor. An oxide passivation layer 30 is applied to the top of the silicon. Note that FIG. 1 shows a contact to region 2 . This is optional, and not necessary for a proper functioning array. [0021] The bipolar transistor—PIN photodiode array of this invention is designed on a single Si chip for application in the back-illuminated systems. The photodetector chip can be flip chip die attached to the down stream electronics using a single or multiple pads per pixel. For the bipolar NPN transistor—PIN photodiode array of FIG. 1 , a single signal pad 23 is connected to the transistor emitter. The collector/cathode pads 22 can be made in the intersections of the cathode isolating walls similar to the structures described in the literature (see. U.S. Pat. No. 6,762,473 and “The structure and physical properties of ultra-thin, multi-element Si pin photodiode arrays for medical imaging applications” (B. Tabbert et al., In Medical Imaging 2005: Physics of Medical Imaging, Proceedings of SPIE, 5745 (SPIE Bellingham, Wash., 2005), 1146-1154)). The bias is applied to the collector/cathode pad, which is the transistor emitter-collector bias and at the same time a reverse photodiode bias. The anode/base pad 21 may be connected, used only for diagnostics, or eliminated. [0022] The resistivity of the starting material can be lower than in the case of the bare PIN photodiode array to minimize the photodiode leakage current. Note that the photodiode leakage current is also the transistor base current, which determines the transistor sensitivity. [0023] The bipolar transistor—PIN photodiode array structure shown in FIG. 1 assumes N-type Si substrate as a starting material. P-type substrates could also be used and similar structures with bipolar transistors of different polarities could be realized. [0024] The Si substrate thickness can be 150 um or smaller; however, there is no physical limitations on the substrate thickness within the current inventions. The substrate thickness may influence some functional parameters of the array elements. [0025] The bipolar transistor—PIN photodiode array of this invention has several advantages that might be important for CT and other imaging applications. These include low output (emitter/base junction) capacitance, high gain (>100× as compared to the bare PIN photodiode array), and fast response time (comparable to that of the PIN photodiode arrays reported recently in “Ultra-thin, two dimensional, multi-element Si pin photodiode array for multipurpose applications”, R. Metzler et al., In Semiconductor Photodetectors 2004, Proceedings of SPIE, 5353 (SPIE Bellingham, Wash., 2004), 117-125)). II. JFET—PIN Photodiode Back-Illuminated Array. [0026] The structure of the JFET—PIN photodiode array elements built on a high resistivity Si wafer is shown in FIG. 3 . The isolation diffusion 4 between the adjacent pixels (cathode deep diffusion in FIG. 3 ) is naturally incorporated in the design of U.S. Pat. No. 6,762,473. The active area diffusion 2 (anode diffusion in FIG. 3 described also in U.S. Pat. No. 6,762,473), is also a part of the structure. Note that both the isolation diffusion and active area implant/diffusion may not necessarily be deep. Shallow diffusions can also be integrated with the JFET and are therefore considered as an alternative embodiment of the present inventions. [0027] The transistor structure in FIG. 3 is an N-channel JFET working in either enhancement or depletion mode. Note that the enhancement mode provides a better sensitivity to the small optical signals. In FIG. 3 , gates 16 & 15 of the JFET are common to the photodiode anode 2 (by being overlapping P-type diffusions), and the drain 14 is common to the photodiode cathode 3 (both being N-type overlapping diffusions). This JFET structure is created by applying a deep uniform p-type diffusion that serves as the bottom gate 16 for JFET. Then source and drain N-type diffusion 13 - 14 is made, which creates the N-type channel of JFET. At the end, a P-type implant that serves as the top gate 15 is applied. The top gate implant is driven deep enough to provide either the depletion or enhancement mode of JFET operation as desired. FIG. 3 shows contacts on region 2 and top gate region 15 . These contacts are optional, and not necessary for a proper functioning array. A possible circuit schematic is shown in FIG. 4 . [0028] As in the case of the bipolar transistor—PIN photodiode array, the JFET—PIN photodiode array of this invention is designed on a single Si chip for application in the back-illuminated systems. The photodetector chip can be flip chip die attached to the down stream electronics using a single or multiple pads per pixel. For the JFET—PIN photodiode array of FIG. 3 , a single signal pad for each pixel of the array is the one connected to the transistor source 13 . The source may also be connected to the top gate by the gate resistor R G of FIG. 4 , which could be either internal or external to the silicon. The resistor value is chosen from the consideration that it should provide a proper operating potential on the transistor top gate when the photocurrent is collected by the PIN photodiode anode. In some applications this resistor value may be made infinite by eliminating it. The drain/cathode pads 22 can be made in the intersections of the cathode isolation walls similar to the structures described in the literature (U.S. Patent No. U.S. Pat. No. 6,762,473 and “The structure and physical properties of ultra-thin, multi-element Si pin photodiode arrays for medical imaging applications” (B. Tabbert et al., In Medical Imaging 2005: Physics of Medical Imaging, Proceedings of SPIE, 5745 (SPIE Bellingham, Wash., 2005), 1146-1154)). The bias is applied to the drain/cathode pad, which is the JFET N-channel bias and at the same time a reverse photodiode bias. The top gate pad 15 may be used for diagnostic testing, attached to external control circuits, or eliminated as needed for the desired application. [0029] The JFET—PIN photodiode array structure shown in FIG. 3 assumes N-type Si substrate as a starting material. The P-type substrates could also be used and similar structures with JFETs of different polarities could be realized. [0030] The JFET—PIN photodiode array of this invention has several advantages that might be important for CT and other imaging applications. These include low output (gate/source junction) capacitance, high gain (1000× and more as compared to the bare PIN photodiode array), and low leakage current (noticeably lower than that of the bipolar transistor—PIN photodiode array). [0031] The back illuminated photo-transistor arrays, described in the present invention, can be used not only for CT scanners but also for other medical imaging applications such as PET, SPECT, and scanners for non-medical purposes. The advantages of the present invention designs over the conventional back-illuminated PIN photodiode arrays are applicable in numerous applications other than medical imaging applications, such as industrial CT scanners, laser ranging, vibrometers, doppler imagers, etc. Employing such arrays may also significantly improve the power load/dissipation parameters of the detector modules in comparison with the conventional design systems. [0032] The Si substrate thickness suitable to build Bipolar—or JFET—photodetector arrays can be 150 um or smaller; however, there is no physical limitations neither from the low side nor from the high side on the substrate thickness within the current inventions. The substrate thickness may influence some functional parameters of the array elements. [0033] One of the versions of the above described array of pin photodiodes with integrated bipolar or field-effect transistors comprises more than one transistor per each photodiode pixel. Such modified structure allows improving the pixel's dynamic range, time response, and signal-to-noise ratio due to a possibility to better match the input capacitance of the amplifying transistor with that of the photodiode sensitive element. [0034] FIG. 5 shows a schematic example of the top view of a single pixel of the array with six integrated field effect transistors. Each of the transistors integrated in the pixel is shown with the squares 40 . A single pixel of the photo-detector array in this case consists of several micro-pixels, connected in parallel. Similar to the structure of FIG. 3 , the cathode pads 22 provide at the same time the contacts to the drain. Each micro-pixel may have its own drain pad 22 ; however, they all must be connected in parallel either on the chip (as it is shown in FIG. 5 ) or on the substrate, to which a flip-chip die attach is made. The example of the on-chip electrical connections between the drain/cathode pads 22 is shown with the lines 41 . The source pads 24 of each micro-pixel are also connected in parallel with the lines 42 . Such connections may be made either on chip or on the substrate. [0035] FIG. 5 can be also thought of as a top view schematic representation of a single pixel of the bipolar phototransistor array. In this case, the pads 22 will contact the cathodes/collectors of micro-pixels, whereas the pads 23 will contact the micro-pixel emitters. [0036] The example of the cross-sectional view of the structure containing several JFET amplifiers per pixel is presented in FIG. 6 . Similarly to the structures shown in FIG. 1 and 3 , each pixel of the structure in FIGS. 5 and 6 can be surrounded by the isolation diffusion 4 . Note that this diffusion may not necessarily be a through diffusion. The anode diffusions 2 of micro-pixels are isolated from each other, providing thus an independent P/N junction for each micro-pixel. Under proper bias conditions, the depletion propagates from each P/N junction into the Si substrate, creating normal operating conditions for the pin diode of each micro-pixel. [0037] A structure, consisting of multiple bipolar transistors integrated with independent anodes (micro-pixels) can be realized for each pixel of the bipolar transistor array of FIG. 1 , as shown in FIG. 7 . [0038] Note also that the described above structures with multiple bipolar or field-effect transistors per photosensitive pixel can be useful in designing not only the imaging arrays but single-pixel photodetectors as well. This allows creating high-gain, high quantum efficiency, and fast back-illuminated detectors with a large active area. [0039] An important feature of the designs discussed in FIGS. 5 , 6 , and 7 is a small junction area of the photosensitive element belonging to each transistor of the whole photosensitive cell. This allows significantly decreasing capacitance and improving frequency response characteristics of the sensitive elements without compromising the other functional parameters of the detector. [0040] Similar approach of separating the large detector pixel onto the array of connected in parallel sub-pixels can be used to build array detectors of other types, not only those photo-transistor arrays that include bipolar or junction field effect transistors. The other types of devices that provide initial amplification of photo current can be also considered. Among those are MOSFETs and many other types of field effect transistors. In addition, the arrays containing avalanche photodiodes (APDs), CCD and CMOS could be mentioned here. Note also that some realizations of the ideas presented in this invention are already available for the photodetectors consisting of the arrays of micro-pixels of Gaiger-mode avalanche photodiodes. However, the structure of the available detectors is different from what is proposed here.	Back-illuminated photo-transistor arrays for computed tomography and other imaging applications. Embodiments are disclosed that use bipolar transistors and JFETs, either with a single photo-sensor and transistor per pixel, or multiple photo-sensors and transistors per pixel.	7
FIELD OF THE INVENTION The present apparatus and method relates to spray coating sheet materials and, more particularly, to an apparatus and method for spray coating sheet material with a heated and atomized liquid compound to decrease coating drying time, improve coating quality and increase production efficiency. BACKGROUND OF THE INVENTION Application of spray coatings to sheet materials, such as forming lubricants sprayed onto sheet metal or coiled steel, that undergo drawing operations exposing the sheet and lubricant to extreme pressures are known in the art. The application of lubricants suitable for sheet metals varies on the forming process used, material to be coated and the properties of the lubricant itself. It has long been known to apply common oils and greases to lubricate the sheet to facilitate drawing or forming and to prevent unwanted thinning or tearing of the material. In the case of ferrous materials, the greases and oils further acted to prevent premature corrosion. These common greases or oils, however, were difficult to remove since such solvents required special handling and storage. During World War II, oils and greases became difficult to obtain, and it was discovered that borax or soap-based lubricants provided the necessary lubrication without having to remove the lubricant prior to subsequent coating of the sheet material with primer or paint. Such soap-based lubricants were dissolvable in water, rolled or sprayed on the sheet material, and eventually dried on the sheet once the water evaporated. The soap-based lubricants, although applied mixed with water, became known as “dry” lubricants as the lubricant is dry at the time of forming the sheet metal. Progression of the sheet metal along the processing line was dependent on the typically lengthy drying time of the lubricant which required reduced line speeds. Due to the need to keep the process line moving, a significant length of floor space was needed to ensure drying of the lubricant prior to further processing. Prior methods for applying dry lubricants were typically conducted by spraying an excessive amount of a lubricant/water mixture onto the sheet material. In order to obtain the recommended or desired coating weight per square foot of material, prior roll coating processes used rubber rollers on the top and bottom surfaces of the sheet metal to squeeze or press the undesired quantity and weight of the sprayed-on lubricant from the sheet material. Such prior art processes provided full coverage of the sheet metal but had numerous disadvantages. The prior roll coating processes are problematic in that dry lubricants are very costly, and the prior art methods used excessive amounts of dry lubricant, much of which was wasted through the spraying and squeezing process and often producing uneven coating weight on the material. The prior art processes were further problematic in that the rubber rollers used to squeeze off excess lubricant were subject to wear requiring reconditioning or replacement and added to uneven coating weight of the dry lubricant. The prior art processes were further problematic in that they slowed the process line speed requiring significant space in the process line and time for the water to sufficiently evaporate from the sheet material. The prior art processes were further subject to significant down time of the process line due to replacement of worn rollers and the necessity to change the rollers between coating production runs. Consequently, it would be desirable to provide a spray coating apparatus and method that improved the problematic conditions in the prior art, that is efficient in applying a desired coating weight, that improves the consistency of the coating, that reduces clogging of the apparatus, that facilitates an increase in productivity through an increase in process line speed, that reduces the space required for the apparatus in the process line and space needed for drying the coating, and that is simple and relatively inexpensive to produce and operate. SUMMARY OF THE INVENTION The spray coating apparatus of the present invention includes a base having a batch tank positioned thereon which is used to contain and mix water with a water soluble material to form a liquid compound. The apparatus includes at least one spray control valve in fluid communication with the batch tank to selectively dispense the liquid compound from the batch tank to at least one spray nozzle. The apparatus further includes at least one spray nozzle which is adapted to receive the liquid compound from the control valve and receive a supply of heated gas which is mixed with the liquid compound in the nozzle to heat and begin atomizing the compound and spray the atomized compound onto the sheet material. In another embodiment of the invention, the apparatus further includes a spray header positioned along the coating line for the sheet material in spaced relation to the base. The spray header includes a plurality of spray nozzles adapted to receive and communicate with the liquid compound and the heated gas. In another embodiment of the invention, steam is used as the heated gas that is placed in communication with the liquid compound. In yet another embodiment of the invention, a process tank is positioned on the base in fluid communication with the batch tank to hold a reserve of mixed liquid lubrication compound to be sent to the spray control valve. In an additional embodiment, a user control terminal is positioned on the base for monitoring and controlling the mixing of the liquid lubrication compound and the spraying of the atomized lubricant on the sheet material. The present invention also provides a method for applying a spray coating to sheet material including the steps of adding a water soluble material to a quantity of water in a batch tank and mixing the material with water in the batch tank to form a liquid compound. The liquid compound is selectively dispensed under pressure to at least one spray nozzle. The liquid compound is then atomized and sprayed onto the sheet material traveling along a coating line. In another embodiment of the inventive method, the water and liquid compound in the batch tank are heated in the batch tank. In another embodiment, the spray nozzles are adapted to receive and communicate the liquid compound and a heated gas to further heat the liquid compound and begin atomizing the liquid compound. In yet another embodiment of the inventive method, a process tank is provided in fluid communication with the batch tank to store a reserve of liquid lubrication compound to be selectively dispensed to the spray nozzle. In an additional embodiment of the inventive method, a plurality of spray control valves and spray nozzles are provided for dispensing the liquid lubrication compound through selected valves to selected nozzles to coat the material sheet. In even another embodiment of the inventive method, a heated gas is supplied to a jacket in the spray nozzle to heat and deter clogging of the nozzle. In a further embodiment of the inventive method, a user control terminal is provided to control and monitor the mixing and spraying of the atomized lubrication compound to the sheet material along the coating line. Other applications of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein: FIG. 1 is a partial schematic view of the apparatus and method including the batch mixing assembly including the batch tank recirculation components; FIG. 2 is a partial schematic view of the apparatus and method including the process mixing assembly including the process tank recirculation components and monitoring sensors; FIG. 3 is a partial schematic of the apparatus and method including the flow control valves for the spray header device; FIG. 4 is a partial front elevational view of the spray header; FIG. 5 is a side elevational view of the spray header device shown in FIG. 4; FIG. 6 is a partial plan view of the spray header device shown in FIG. 4; FIG. 7 is a sectional view taken along line A—A in FIG. 4; FIG. 8 is an enlarged view of an area circled in FIG. 4; FIG. 9 is a partial schematic of the apparatus and method of the present invention showing the base, batch mixing and process mixing assemblies, user control terminal and spray control valves; and FIG. 10 is a partial, cut-away schematic of the apparatus and method showing the spray header, coating line and material sheet. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1-10, an apparatus and method 10 for applying a spray coating to sheet material is illustrated. Referring specifically to FIGS. 1 and 9, the apparatus 10 includes a batch mixing assembly 12 including a batch tank 14 positioned on a rigid base 15 as shown in FIG. 9 . Batch tank 14 is a cylindrically-shaped, vertically oriented holding tank having a capacity of approximately 200 gallons and base 15 is a rectangularly-shaped rigid steel plate suitable for moving by a forklift or overhead crane. Batch mixing assembly 12 includes a first mixer 16 positioned above batch tank 14 and includes a shaft 17 and first impeller 18 extending downwardly into batch tank 14 as best seen in FIG. 1 . Batch mixing assembly 12 further includes a batch liquid level sensor 20 which extends downwardly into batch tank 14 . Batch mixing assembly 12 further includes a batch pump 26 which is in fluid communication with the batch tank 14 through batch recirculation line 27 . As best seen in FIG. 1, a supply of water is provided under pressure to batch tank 14 through water line 28 . The flow of water is controlled by an inlet water valve 30 . Inlet water valve 30 is a pneumatically operated control valve receiving air under pressure through air line 32 from an air header 128 shown in FIG. 3 . Inlet water valve 30 is operated and monitored by signals sent to and received from a user control terminal 22 as seen in FIG. 9 through control signal input line 23 and control signal output line 24 . Control terminal 22 is a personal computer, not shown, having software adapted to the apparatus and process and a touch-screen user interface as described below. Batch mixing assembly 12 further includes a heating element 40 positioned inside batch tank 14 as seen in FIG. 1 . The apparatus includes a heating element 40 which is a coil heated by a heated gas, most preferably steam, supplied under pressure through batch steam lines 36 and 37 . The heating element 40 is positioned at the 45 gallon point in the 200 gallon capacity batch tank 14 . Steam for heating element 40 is controlled by a batch steam control valve 38 which is pneumatically operated through connection to the pressurized air line 32 . Steam control valve 38 is controlled and operated by the user control terminal 22 through signal input 23 and signal output 24 lines as previously described. Batch steam control valve 38 is electronically connected to a batch tank temperature sensor 42 which protrudes into batch tank 14 to monitor the temperature of the liquid contents in batch tank 14 and to transmit the temperature to the user control terminal 22 which in turn signals steam control valve 38 to open and close as needed. In an alternate aspect, the heated gas is heated air instead of steam. Batch mixing assembly 12 further includes a three-way batch solenoid valve 50 positioned between batch tank 14 and batch pump 26 in batch recirculation line 27 as best seen in FIG. 1 . Pneumatically operated batch solenoid valve 50 is controlled and operated by user control terminal 22 . Batch mixing assembly 12 also includes an inlet port 52 in batch tank 14 for adding a water soluble material in the form of liquid, powder, pellets or other form of media to the batch tank 14 to be mixed with the water to form a liquid compound. The spray coating apparatus and method preferably further includes a process mixing assembly 60 as best seen in FIGS. 2 and 9. The process mixing assembly 60 stores a reserve of heated and mixed liquid compound that stands ready for disbursement while a new batch of liquid compound is heated and mixed. The reserve of liquid compound provides a continuous or almost continuous supply of liquid compound to support the needs of the coating line. Where such continuous supply of compound is not needed or downtime is not critical, the batch tank assembly 12 may be employed without the need for process mixing assembly 60 . Process mixing assembly 60 includes a process tank 62 similar in configuration and capacity as batch tank 14 . Process mixing assembly 60 further includes a second mixer 64 extending downwardly into process tank 62 and includes a second impeller 66 for mixing the contents of the process tank 62 . Process mixing assembly 60 further includes a process tank level sensor 68 extending downwardly into process tank 62 for monitoring the level of liquid in the tank. Process mixing assembly 60 further includes a process pump 74 in fluid communication with process tank 62 through process recirculation line 76 . Process mixing assembly 60 also includes a process tank inlet line 78 which is in fluid communication with batch solenoid control valve 50 to permit flow of fluid from batch tank 14 to process tank 62 through opening of batch solenoid valve 50 on signal from the user control terminal 22 . The preferred process mixing assembly 60 further includes a heating element 88 positioned inside process tank 62 similar in construction, position and function as heating element 40 in batch tank 14 . Heating element 88 is preferably heated by steam provided under pressure from steam line 36 through process steam inlet line 82 and process tank steam control valve 84 . Process tank steam control valve 84 is pneumatically operated and controlled by user terminal 22 and is electronically connected to process tank temperature sensor 92 as previously described for valve 38 and sensor 42 in batch tank 14 . Process mixing assembly 60 further includes a process recirculation valve 98 positioned between process tank 62 and process pump 74 and is pneumatically controlled and operated by user control terminal 22 to permit the flow of fluid from process tank 62 through recirculation line 76 . Process mixing assembly 60 further includes a first steam purge line 102 in gaseous communication with steam line 36 . A first steam purge solenoid valve 104 is positioned in steam purge line 102 to selectively permit the passage of steam to and through process tank inlet line 78 to flush the line with steam to disperse sedimentation and prevent clogging as further described below. In an alternate aspect, heated air is used instead of steam. Process mixing assembly 60 further includes a process tank outlet 110 and a process three-way solenoid control valve 112 in fluid communication with process recirculation line 76 . The solenoid valve 112 is pneumatically operated and controlled by user terminal 22 in a similar fashion as batch solenoid control valve 50 as previously described. Solenoid valve 112 selectively permits the passage of fluid from process tank 62 to the remainder of the system as described immediately below. The spray coating apparatus and method 10 further includes at least one spray control valve 124 , and most preferably nine spray control valves 124 ( a )-( i ) as best seen in FIG. 3 . In a preferred aspect of the invention, spray control valves 124 are positioned in adjacent proximity to spray header 150 discussed below. For simplicity of illustration, in an alternate aspect, spray control valves 124 are positioned on base 15 as shown in FIG. 9 . Spray control valves 124 are positioned in fluid communication with process tank outlet 110 through process tank solenoid control valve 112 and through spray valve inlet line 136 . Spray valve inlet line 136 permits the selective passage of fluid to the spray control valves 124 through a spray valve manifold 126 . The spray control valves 124 are pneumatically operated and controlled by user control terminal 22 through the pressurized air header 128 and air line 32 . Spray control valves 124 further include spray control valve outlet lines 144 having one outlet line 144 for each spray control valve 124 ( a )-( i ). The spray coating apparatus and method 10 further include a spray header 150 as best seen in FIGS. 4 through 8 and 10 . Spray header 150 includes an upper header frame 154 and a lower header frame 156 as best seen in FIG. 4 . Upper frame 154 includes upper support columns 158 and an upper beam 162 . Lower frame 156 includes lower support columns 160 and a lower beam 164 . Upper 158 and lower 160 support columns are vertically adjustable through elbows 161 to accommodate different heights of the coating line 234 and sheet material to be coated. Upper and lower beams 162 , 164 , respectively, include a cover 166 to close the open surface of the beams. In a preferred aspect, 3×3 inch square steel tubing is used for the lower portion and 2½×2½ inch square steel tubing for the telescoping upper portion of upper 158 and lower 160 column supports. Upper 162 and lower 164 beams are made from thin gage steel in a C-shaped section having a corrosion resistant coating. Spray header 150 is positioned in spaced, but adjacent, relationship to base 15 while remaining in fluid and gaseous communication with process mixing assembly 60 and steam line 36 . It is contemplated that to aid in space reduction and further portability, spray header 150 may be attached to base 15 . Spray header 150 further includes a spray manifold 170 attached to one of the upper support columns 158 as best seen in FIGS. 4 and 5. Spray manifold 170 includes nine manifold steam inlet receptacles 172 and 18 manifold steam outlet lines 174 . Steam inlet receptacles 172 receive a heated gas, most preferably steam, under pressure from nine steam lines, not shown, in gaseous communication with steam line 36 . In an alternate aspect, heated air is used instead of steam for the heated gas. Spray manifold 170 further includes nine liquid compound fluid inlet receptacles 176 and 18 manifold liquid lubrication outlet lines 178 , nine of the fluid outlet lines 178 being routed to upper beam 162 and nine fluid lines 178 routed to lower beam 164 . In similar fashion, nine of the manifold steam outlet lines 174 are routed to upper beam 162 and nine are routed to lower beam 164 . Manifold 170 further includes a nozzle jacket steam inlet receptacle 192 and two nozzle jacket steam outlet lines 194 , one line 194 being routed to upper beam 162 and one routed to lower beam 164 as seen in FIG. 4 . Nozzle jacket steam inlet receptacle 192 is most preferably in gaseous communication with steam line 36 . In an alternate aspect, heated air is used instead of steam as the heated gas. Spray header 150 further includes at least one spray nozzle 184 and most preferably a total of 18 spray nozzles 184 spaced in relation to one another as best seen in FIGS. 4-6. Nine nozzles 184 are spaced in longitudinal and lateral orientation from one another across upper beam 162 and lower beam 164 as best seen in FIGS. 4 and 6. A row of five nozzles placed at a distance 250 apart are separated by a distance 252 from a second row of four nozzles spaced at a distance 250 apart from one another for spray coating sheet material 228 . The distance 250 between nozzles 184 is approximately 16 inches apart on center of each nozzle and the distance 252 between rows is approximately two inches. In a most preferred embodiment, each nozzle 184 is adapted to receive a steam outlet line 174 and a liquid compound outlet line 178 from the manifold 170 . Each nozzle 184 also includes a spray nozzle jacket which is adapted to receive a steam outlet line 194 from manifold 170 as best seen in FIGS. 4, 7 and 8 . Each nozzle 184 is adapted to place liquid from manifold liquid outlet lines 178 in direct communication with a heated gas, most preferably steam, from manifold steam outlet lines 174 to further heat and begin atomizing the liquid compound. In an alternate aspect, heated air is used instead of steam for the heated gas for either or both atomizing the liquid compound and heating the nozzle jacket. The at least partially atomized lubrication compound is forced to exit nozzle 184 under pressure as an atomized spray 200 having a spray width 202 and length 204 as best seen in FIG. 8 . Spray header 150 is positioned along the sheet material coating line 234 and is adapted to receive sheet material 228 between the upper beam 162 and lower beam 164 passing between the spray nozzles 184 placing an upper and a lower surface of the sheet material, not shown, in spray communication with spray nozzles 184 suitable to provide a desired coating weight on the upper and lower surface of sheet material 228 . Sheet material 228 is supported by a conveyor, not shown, traveling along coating line 234 and is interrupted for a brief length prior to and through spray header 150 and recommences to support and carry the sheeting material for drying and subsequent processing. Referring to FIG. 2, spray coating apparatus and method 10 further includes a second steam purge line 212 in gaseous communication with steam line 36 to flush the lines or path the liquid lubrication compound follows between the process solenoid valve 112 and spray nozzles 184 . The passage of steam through second purge line 212 into spray inlet line 136 is controlled by a second steam purge solenoid valve 214 in gaseous communication with spray valve inlet line 136 . Steam purge solenoid valve 214 is pneumatically operated from pressurized air from air line 32 and controlled by signals from user control terminal 22 . Spray coating system 10 further includes a third steam purge valve 218 in gaseous communication with steam line 36 to selectively permit the flow of steam from steam line 36 to the steam manifold inlet receptacles 172 through steam purge line 220 . Valve 218 is pneumatically controlled through pressurized air from air line 32 and controlled by signals from user control terminal 22 . Steam purge line 220 further includes a steam flow sensor 222 and pressure sensor 226 which monitors and signals user control terminal 22 for display to the user. In an alternate aspect, heated air is used instead of steam. Referring to FIGS. 1 through 10, the inventive method of the present invention is illustrated. Prior to filling and initiating spraying by the spray coating apparatus 10 , several operator inputs or variables must be defined. The user control terminal 22 includes a computer display monitor, not shown, having an operator interface touch screen (HMI). The operator interface includes an initial Setup Screen or mode programmed in the user control terminal 22 computer software, not shown, for input of the linear speed of the mill line which is the speed the sheet material 228 will be traveling along the coating line 234 . At this Setup Screen, the width of the mill strip or sheet material 228 is also manually entered. It is contemplated that additional sensors, not shown, could operate to automatically detect and monitor the width of sheet 228 and monitor the linear speed of the sheet material 228 traveling along coating line 234 and provide representative signals to user control terminal 22 versus manually entering the speed and width as described above. In the event sensors are available and are automatically monitoring line speed and material width, an Automatic feature or mode on the operator interface screen could be employed versus a manual feature or mode whereby the operator manually inputs the information as described above. In order to initiate the filling of the spray coating apparatus 10 , a Tank Setup feature or mode is accessed by a user on the user interface. At the Tank Setup screen, the user can manually set a high liquid level and low liquid level for the batch tank 14 . Using a 200 gallon batch tank, a high level set point of 150 gallons and a low level set point of 45 gallons is input or established as a default in the control terminal 22 program. On input of the information under the Tank Setup screen, the user proceeds to a Batch Mixing Tank screen displayed on the user interface. On the Batch Mixing Tank screen, an option to select a Fill To 50% button is pushed or activated to initiate the flow of water under pressure through water line 28 . The user control terminal provides a signal to automatically open pneumatically operated water inlet valve 30 which permits flow of water into batch tank 14 . Once the level of water in batch tank 14 achieves the low liquid level amount of 45 gallons, user control terminal 22 sends a signal to open batch steam inlet valve 38 permitting a heated gas, most preferably steam, to flow into batch heating element 40 to heat the water while the water continues to rise. In an alternate aspect, heated air is used instead of steam for the heated gas. At approximately this point, user control terminal 22 will signal and start the first mixer 16 and place the batch pump 26 in a recirculation mode. In this mode, batch pump 26 will draw water from a lower portion of batch tank 14 and force the water through batch recirculation line 27 for deposit of the warming water into an upper portion of batch tank 14 as seen in FIG. 1 . The mixer 16 will provide agitation to mix and uniformly heat the water. Once the batch tank 14 is filled to one-half of the desired high liquid level point of 150 gallons and reaches a temperature of approximately 180° F. as measured by batch temperature sensor 42 , an indicator visible on the interface screen of the user control terminal 22 to Add Powder will be enabled permitting the operator to add a necessary amount of water soluble material to the heated water. In one embodiment, the material is a water soluble forming lubricant for sheet metal. In a preferred embodiment, a borax-based “dry” sheet metal drawing lubricant, as previously described, is added to the heated water in powdered form through inlet 52 in batch tank 14 to form a liquid lubrication compound. For exemplary purposes only, a suitable borax-based, water-soluble dry drawing lubricant is T.C. 1800-3 manufactured by Tru-Chem Co., Inc. of Columbus, Ohio. It is contemplated that other borax-based, water-soluble dry lubricants and other water soluble materials, in powdered, liquid, flaked, pelletized, granular, or other forms, may be used without departing from the present invention. The amount of water soluble material added to the heated water in batch tank 14 is dependent on several factors including: the width of the sheet material 228 , the line or linear process speed of sheet material 228 that passes spray header 150 in a given period of time and the desired weight of the coating to be applied to the sheet material. It has been determined that 24.5 oz. of T.C. 1800-3 to one gallon of water will achieve a coating weight of approximately 300 mg/sq. ft. Once the water soluble material is automatically or manually added to batch tank 14 , the user acknowledges that the powder has been added by pressing the Add Powder acknowledgment button or prompt on the user interface of user control terminal 22 . To continue the process, the operator next activates a Fill To 100% button visible on the Batch Mixing Tank screen on the user interface which signals and re-opens water inlet valve 30 permitting additional water to enter the batch tank 14 . Once sufficient water is added to batch tank 14 to reach the desired high liquid level set point of 150 gallons, the user control terminal signals and closes water inlet valve 30 preventing additional water from entering the batch tank. In one embodiment, when batch tank 14 is filled to 150 gallons, first mixer 16 will continue mixing the liquid lubrication compound for 30 minutes while batch heating element 40 maintains the liquid lubrication compound at approximately 180° F. Throughout this time, batch pump 26 remains in a recirculation mode to recirculate the liquid lubrication compound through recirculation line 27 to deter sedimentation and clogging in the pump and recirculation line. Following the preferred 30 thirty minutes mixing time period at 180° F., a Batch Ready prompt will be displaced on the user interface on the user control terminal 22 . The liquid lubrication compound is now ready for distribution from the batch tank to the spray control valves 124 . In another embodiment of the inventive method, a process mixing assembly 60 is placed on base 15 in liquid communication between the batch tank 14 and the spray control valves 124 . The process mixing assembly 60 permits a reserve of heated and mixed liquid lubrication compound to be stored while the batch tank 14 is refilled, the water is heated, and the lubrication is mixed while the process mixing assembly 60 stands ready or supports active spraying. The reserve of prepared liquid lubrication provides for a near constant flow of liquid lubrication compound to the spray header 150 to support the coating line. As explained, if a reserve is not required, the liquid lubrication compound may be dispensed directly from the batch tank 14 . In yet another embodiment of the inventive method, batch pump 26 is taken off the recirculation mode by the user control terminal 22 and the three way batch solenoid control valve 50 is opened to permit batch pump 26 to force liquid lubrication compound from batch tank 14 along process tank inlet 78 to an upper portion of process tank 62 to begin filling the process tank as seen in FIG. 2 . Once the liquid lubrication compound reaches the predetermined lower liquid level of 45 gallons as measured by the process liquid level sensor 68 , process tank heating element 88 will be heated through the opening of process steam control valve 84 by the user control terminal 22 . The contents of batch tank 14 will be pumped into process tank 62 until the liquid level in batch tank 14 reaches the predetermined low level point of 45 gallons effectively transferring 105 gallons to the process tank. It is desired that the contents of batch tank 14 not fall below the 45 gallon liquid low level mark which would fall below the position of batch heating element 40 and allow the liquid lubrication compound in batch tank 14 to begin to cool. In a similar fashion, it is understood that subsequent batches of liquid lubrication compound from batch tank 14 to batch tank 62 will raise the contents of process tank 62 to the desired predetermined high liquid level mark of 150 gallons as the transfer of 105 gallons will be added to the 45 gallons already in process tank 62 left from the prior batch. Once the transfer to batch tank 14 to process tank 62 has been made and batch tank 14 is at the low liquid level of 45 gallons, the user control terminal 22 will signal and close the batch solenoid valve 50 and place batch pump 26 and process pump 74 in a recirculation mode to deter sedimentation and clogging of the liquid lubrication compound. While batch solenoid valve 50 is closed preventing additional liquid lubrication compound from passing to the process tank 62 , the process tank inlet line 78 is flushed with heated gas, most preferably steam, to clear the line and prevent sedimentation and clogging of the line. This accomplished through opening of the first steam purge solenoid valve 104 as best seen in FIG. 2 to allow the steam under pressure to pass through first steam purge line 102 into process tank inlet line 78 purging the steam and residual liquid lubrication compound into process tank 62 . Flushing of process inlet line 78 continues for approximately 15 minutes. In an alternate aspect, heated air is used instead of steam for the heated gas. If additional liquid lubrication compound is required to support the coating line 234 beyond the reserve in process tank 62 , the operator can again initiate filling and mixing of the batch tank through the Batch Tank screen through the method previously described. Upon depleting the liquid lubrication compound in process tank 62 to the predetermined low liquid level line of 45 gallons, user control terminal 22 halts recirculation mode of batch pump 26 , opens batch solenoid valve 50 and batch pump 26 again transfers the 105 gallons of heated and mixed liquid lubrication compound from batch tank 14 to process tank 62 as previously described. On achieving the predetermined high liquid level mark of 150 gallons in process tank 62 and the preferred temperature of 180° F. is achieved through monitoring by process tank temperature sensor 92 , dispensing of the liquid lubrication compound to the spray control valves 124 is initiated by either of two ways: Automatic or Manual Mode. In the Automatic Mode, once the system prerequisites of liquid level and temperature are met, user control terminal 22 halts recirculation mode of process pump 74 , opens process recirculation valve 98 and opens three-way process solenoid valve 112 . User control terminal 22 automatically activates the process pump 74 to begin pumping the heated liquid lubrication compound to the spray control valves 124 . A visual indicator will be displayed on the user interface indicating the sprays are On. In the Manual Mode, the user will receive a prompt through the user interface that the system is ready to initiate spraying. The user then activates a Spray On prompt or button. Once the sprayers are placed in an On position by either automatic or manual mode, the liquid lubrication compound will be permitted to pass from the process tank 62 to the spray control valves 124 . The liquid lubrication compound will be supplied under pressure by process pump 74 to at least one, and most preferably nine, pneumatically controlled spray control valves 124 ( a )-( i ) through spray valve inlet line 136 to a spray valve manifold 126 as best seen in FIG. 3 . In order to maximize the efficiency of spraying the sheet material 228 and thereby minimizing waste of the liquid lubrication compound, spray control valves 124 ( a )-( i ) will be selectively opened depending on the width of the sheet material 228 that is either automatically determined on the coating line 234 or manually input by the user at the Setup Screen as previously described. Referring to FIG. 3, the following valves are selectively opened to provide adequate coating to a sheet 228 based on standard sheet metal roll widths noted below. Sheet material 228 in a 24 inch width: open spray control valves 124 ( g )-( i ); Sheet material 228 in a 34 or 40 inch width: open spray control valves 124 ( e )-( i ); Sheet material 228 in a 48 inch width: open spray control valves 124 ( c )-( i ); and Sheet material 228 in a 62 or 72 inch width: open spray control valves 124 ( a )-( i ). Referring to FIGS. 3-5, each spray control valve 124 through spray manifold 170 provides liquid lubrication compound to two spray nozzles 184 , one nozzle on upper beam 162 and one nozzle on lower beam 164 . For example, for sheet material 228 in a 24 inch width, three spray control valves are opened providing liquid lubrication compound to a total of six spray nozzles 184 , three spray nozzles on the upper beam 162 and three nozzles to the lower beam 164 . In order to provide or support the required spray nozzles 184 to apply the desired coating weight, the process tank valve 98 is opened and adjusted to a position to provide the necessary volume of liquid lubrication compound to the spray control valves. As explained above, the proper volume of liquid lubrication compound depends on the width of sheet material 228 , the linear speed sheet metal 228 is traveling along the coating line 234 , and the desired coating weight. To achieve active monitoring of the flow and pressure of liquid lubrication compound in spray valve inlet line 136 , a flow sensor 138 and pressure sensor 140 are positioned in line 136 as seen in FIG. 2 . Signals from sensors 136 and 138 to control terminal 22 through control signal input 23 and output 24 lines are compared against acceptable figures stored in user terminal 22 software and the flow of liquid lubrication compound is adjusted through valve 98 to maintain acceptable volume passing to the spray control valves 124 . On passage of the liquid lubrication compound through the selected spray control valves 124 , the liquid lubrication compound passes to the spray manifold 170 and into fluid inlet receptacles 176 depending on which spray control valves 124 are open. For each control valve outlet line 144 providing fluid to a particular fluid inlet receptacle 176 , the fluid is divided in manifold 170 to provide fluid to two nozzles 184 , one nozzle on the upper beam 162 and one nozzle on the lower beam 164 . Manifold fluid outlet lines 178 provide the liquid lubrication compound for the particular control valves to the respective spray nozzles 184 . Simultaneously, a heated gas, most preferably steam, under pressure from steam line 36 is provided to the spray manifold 170 and into steam inlet receptacles 172 as shown in FIG. 5 . Steam will be supplied to all 18 of the nozzles 184 compared with only the selected nozzles 184 receiving liquid lubrication compound. Supply of steam to all of the nozzles aids in the atomization of the liquid lubrication compound sprayed from the activated nozzles 184 and aids in controlling and confining the spray pattern to the desired area. To initiate supply of steam to manifold 170 and spray nozzles 184 , user control terminal 22 opens the pneumatically operated steam control valve 218 as best seen in FIG. 2 . To monitor and control the flow and pressure of steam provided to spray header 150 in a similar fashion to liquid lubrication compound to the spray control valves 124 , a steam flow sensor 222 and pressure sensor 226 are positioned along spray header steam line 220 and along with user control monitor 22 , steam control valve 218 is adjusted to ensure an adequate supply of steam is available to support spray header 150 . In an alternate aspect, heated air may be used instead of steam as the heated gas. Referring to FIGS. 4, 6 and 8 , as described above, most preferably nine nozzles 184 are placed in spaced relationship to one another on the upper beam 162 and nine nozzles 184 on the lower beam 164 as best seen in FIGS. 5 and 6. Each nozzle 184 is adapted to receive a single and dedicated liquid lubrication outlet line 178 from manifold 170 and a single, dedicated steam outlet line 174 from manifold 170 . Each nozzle 184 is adapted to place the in-flowing liquid lubrication compound under pressure and incoming steam under pressure in direct fluid and gaseous communication with one another to further heat and atomize the liquid lubrication compound. Through a spray aperture in each of nozzles 184 , atomized spray coating 200 having a width of spray 202 and length of spray 204 is produced as best seen in FIGS. 4 and 8. The heated and atomized spray 200 is directed toward the adjacent upper or lower surface of sheet material 228 to completely coat the material sheet with the desired weight of coating. Spray 200 has a width 202 of approximately 9 inches when the depth of spray 204 is approximately 7½ inches. In a preferred aspect of the invention, the distance 256 between opposing nozzles 184 on upper beam 162 and lower beam 164 is approximately 15⅛ inches as seen in FIG. 4 . Referring to FIGS. 4 and 8, each nozzle 184 preferably includes a nozzle jacket 188 which is adapted to receive an independent supply of a heated gas, most preferably steam, to the nozzle jacket 188 for the purpose of heating the nozzle 184 and further deterring clogging of the nozzle 184 . Steam is supplied to the nozzle jackets 188 from steam line 36 through spray header steam line 220 which supplies manifold 170 with steam in receptacle 192 as seen in FIG. 5 . Manifold 170 provides two steam outlet lines 194 , one for passage of steam to the nozzle jackets 188 on upper beam 162 and one line 194 to the nozzle jackets 188 on lower beam 164 as best seen in FIGS. 4, 5 and 6 . Only one steam outlet line 194 is used to service all of the nozzle jackets 188 on the upper beam 162 and one line 194 to service all of the nozzle jackets 188 on the lower beam 164 as best seen in FIGS. 4 and 6. A suitable connection of steam lines 194 to spray header 150 is shown through section A—A taken from FIG. 4 as shown in FIG. 7 . In an alternate aspect, heated air is used instead of steam for the heated gas. Control of pressurized steam to the nozzle jackets 188 as described is controlled by user control terminal 22 which, when spray control valves 124 are open and providing liquid lubrication compound to the spray header 150 , steam flow control valve 218 is equally opened providing steam to atomize the liquid lubrication compound and simultaneously, providing steam to the nozzle jackets 188 as described. The total flow and pressure of steam provided to atomize the liquid lubrication compound and supplied to the nozzle jackets 188 is monitored by steam flow sensor 222 and pressure sensor 226 as previously described. In operation, the atomized lubrication compound 200 is applied to both upper and lower surfaces of sheet material 228 to completely coat the sheet material with the desired weight of coating. The heating and atomizing of the liquid lubrication compound provides a very consistent coating of sheet material 228 without the use of secondary rollers to squeeze or press excess coating from sheet material 228 . Through selective use of spray nozzles 184 tailored to the width of material sheet 228 , a significant reduction in the amount of spray lubricant that is wasted is achieved. On reaching the trailing end of sheet material 228 traveling along coating line 234 , or when the level of liquid lubrication compound and process tank 62 reaches the predetermined lower liquid level of 45 gallons, spraying of the material sheet is halted. Cessation of spraying may be achieved automatically by sensors, not shown, detecting the end of the sheet 228 or manually through a button or prompt on the user interface. Regarding the former occurrence, if it is anticipated that a short time period will lapse until spraying is recommenced, process mixing assembly 60 will be placed in a recirculation mode by closing a process solenoid control valve 112 thereby circulating the liquid lubrication compound in recirculation line 76 by process pump 74 as previously described. If a longer period is anticipated, the path of the liquid lubrication compound downstream of process solenoid valve 112 is flushed with a heated gas, most preferably steam, or in an alternate aspect heated air, as previously described. This is achieved by the user control terminal 22 opening steam flow control valve 218 which, as described, provides pressurized steam to the spray control valves 124 , manifold 170 , nozzles 184 and nozzle jackets 188 to flush the system of any lubricant residue. This flushing takes place for approximately 15 minutes. Where the level of liquid lubrication compound in process tank 62 reaches the predetermined lower liquid level line of 45 gallons as monitored by process tank level sensor 68 , transfer of a pre-prepared, heated and mixed batch of liquid lubrication compound in batch tank 14 may be simultaneously transferred to the process tank 62 as previously described providing for a continuous flow of liquid lubrication compound to spray header 150 without stopping the coating line 234 . The atomization of the heated liquid lubrication compound through spray 200 provides for quick evaporation of the water in the atomized spray 200 providing for rapid drying of the sprayed-on lubricant on sheet material 228 . Advantages of fast drying the lubricant are two-fold. First, higher line speeds may be used. Second, it greatly reduces the distance required for drying along the coating line 234 once the sheet material passes through spray header 150 . The length required for drying of the sheet material under the present inventive method is up to 90% less than prior art processes. Due to the reduction of space required for drying along the process line and relatively small space required for the spray header 150 along the process line, coating apparatus 10 may be readily installed and positioned to suit the demanding needs of the coating facility. While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.	An apparatus and method for spraying an atomized liquid compound onto a sheet material traveling along a material coating process line. The apparatus and method heats and mixes a liquid compound then atomizes and sprays the atomized liquid compound to coat the sheet material. The apparatus and method selectively provide an atomized liquid compound which improves coating, dries quickly on the sheet material, and increases process line productivity.	1
BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a surface fastener of thermoplastic synthetic resin, in which a multiplicity of engaging elements are integrally molded on a surface of a substrate sheet, and a method of manufacturing the surface fastener. More particularly, the invention relates to a molded surface fastener, in which locking portions of engaging elements are free from catching foreign objects, such as nap, waste pieces of yarn and dust, by accident, and a method of manufacturing the molded surface fastener. 2. Description of the Related Art As an attempt to eliminate a disagreeable rough touch on top ends of engaging elements of a molded surface fastener, Japanese Patent Laid-Open Publication No. Hei 5-285008 discloses a surface fastener molded of synthetic resin in which a shock absorbing sheet softer than the engaging elements and compression-deformable is placed around the individual engaging elements in such a manner that its upper surface is higher in level than top ends of the individual engaging elements. As another measure, Japanese Utility Model Publication No. Hei 6-37710 discloses a surface fastener in which a foam member is disposed between male engaging elements in such a manner that its upper surface is higher in level than the male engaging elements to secure precise positioning of the male engaging elements with respect to engaging elements of a companion surface fastener, preventing the male engaging elements from falling flat. Further, Japanese Patent Laid-Open Publication No. Hei 7-39407 discloses a concept of disposing around engaging elements on a substrate sheet a shock absorbing material, as of sponge, having a height 50-90% of stem portions of the engaging elements in order to reduce possible frictional sound that might occur when companion surface fasteners having mushroom-shaped engaging elements of synthetic resin are coupled together. However, the surface fastener disclosed in Japanese Patent Laid-Open Publication No. Hei 5-285008, of which an abstract disclosure of a manufacturing method is given, does not guarantee that the locking portions of the engaging elements project outwardly from the upper surface of the shock absorbing material in the form of a non-woven cloth so as to engage with mating loop elements reliably at the time of engagement with the companion surface fastener. The whole of the engaging elements tend to be covered by the non-woven cloth, which could not be avoided without making the manufacturing process complex. It is also the case with the surface fastener disclosed in Japanese Utility Model Publication No. Hei 6-37710. On the other hand, Japanese Patent Laid-Open Publication No. Hei 7-39407 discloses nothing about the industrial technique of disposing a shock absorbing material around engaging elements. And it is difficult to secure productivity in manufacturing surface fasteners with minute engaging elements unless special technique is used. Generally, the common problem with the male surface fastener members is that the individual engaging heads tend to catch or hook a garment by accident and hence to give it a damage. According to the surface fastener disclosed in Japanese Patent Laid-Open Publication No. Hei 5-285008 and Japanese Utility Model Publication No. Hei 6-37710, although the engaging elements are free from catching a garment by accident, dust tend to stay in pockets defined around the engaging elements by the shock absorbing material or the foamed member so that smooth engagement with the companion surface fastener is difficult to achieve. According to the surface fastener disclosed in Japanese Patent Laid-Open Publication No. Hei 7-39407, since the upper surface of the shock absorbing material is lower in level than the lower surface of each locking portion of the engaging elements, the locking portions tend to catch waste pieces of yarn and nap as well as dust. SUMMARY OF THE INVENTION It is therefore an object of this invention to provide a surface fastener which enables an economical production, has a less rough engaging-element-side surface, is hard to catch a garment, waste pieces of yarn and nap as well as dust, and guarantees an adequate degree of shape stability of engaging elements. Another object of the invention is to provide a method of manufacturing the described surface fastener. In order to accomplish the above object, according to this invention, there is provided a surface fastener comprising: a substrate sheet; a multiplicity of engaging elements projecting from one surface of the substrate sheet; and an elastic member laying over the one surface of the substrate sheet, the elastic member having an upper surface normally in contact with lower ends of locking portions of the engaging elements and the elastic member supporting circumferential surfaces of stem portions of the engaging elements. Preferably, the substrate sheet and the engaging elements are woven or knitted of fiber yarns and monofilaments, the elastic member being a soft foamed layer of a material non-adhesive to the engaging elements. Alternatively, when the substrate sheet and the engaging elements are integrally molded of thermoplastic resin, the elastic member is a soft formed resin layer and there should be no limitation in adhesiveness. The above surface fastener is manufactured by a first method comprising the steps of: integrally forming the multiplicity of engaging elements, each having a stem portion and a locking portion projecting from an upper end of the stem portion, on one surface of the substrate sheet; and providing the elastic member on the one surface of the substrate sheet between the engaging elements in intimate contact therewith, in such a manner that an upper surface of the elastic member is normally in contact with a lower end of the locking portion of the individual engaging element. The above surface fastener is manufactured by a second method comprising the steps of: integrally forming the multiplicity of engaging elements, each having a stem portion and a locking-portion-forming-end at an upper end of the stem portion, on one surface of the substrate sheet; providing the elastic member on the one surface of the substrate sheet between the engaging elements in intimate contact therewith, in such a manner that the locking-portion-forming ends of the engaging elements project outwardly from an upper surface of the elastic member; and deforming the locking-portion-forming-ends of the engaging elements under heat so as to form the locking portions in such a manner that their lower ends are normally in contact with the upper surface of the elastic member. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 As a fragmentary perspective view showing a molded surface fastener according to a first embodiment of this invention and a companion coupling member; FIG. 2A is a fragmentary cross-sectional view showing the companion coupling member of FIG. 1; FIG. 2B, is a fragmentary cross-sectional view showing the molded surface fastener of FIG. 1; FIG. 3 is a fragmentary cross-sectional view showing the molded surface fastener and the companion coupling member in coupled form; FIG. 4 is a fragmentary cross-sectional view showing a modified form of an elastic layer of the molded surface fastener of the first embodiment; FIG. 5 is a fragmentary cross-sectional view showing a molded surface fastener according to a second embodiment of the invention; FIG. 6 is a fragmentary cross-sectional view showing a modified form of the elastic layer of the molded surface fastener of the second embodiment; FIG. 7 is a fragmentary cross-sectional view showing the molded surface fastener of the first embodiment as coupled with an identical companion surface fastener; FIG. 8 a fragmentary cross-sectional view showing the molded surface fastener of the second embodiment as coupled with an identical companion surface fastener; FIG. 9 is a fragmentary cross-sectional view showing the molded surface fastener of the second embodiment as coupled with an ordinary female surface fastener having loops; FIG. 10 is a fragmentary cross-sectional view showing a surface fastener of fibers according to a third embodiment of the invention; FIGS. 11A, 11B and 11C show the manner in which the molded surface fastener is progressively manufactured in a first method of the invention; and FIGS. 12A, 12B and 12C show the manner in which the molded surface fastener is progressively manufactured in a second method of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of this invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a fragmentary perspective view showing a male molded surface fastener according to a first embodiment of this invention and a female companion surface fastener. In FIG. 1, reference numeral 10 designates a male molded surface fastener which comprises a substrate sheet 11, a multiplicity of mushroom-shaped male engaging elements 12, and an elastic layer 13 of sponge. The substrate sheet 11 and the male engaging elements 12 are previously integrally molded as by injection molding. In a first example of manufacturing method, after a multiplicity of column-like projections are integrally molded on one surface of the substrate sheet 11, the column-like projections, together with the substrate sheet 11, except their upper end portions of a predetermined length are soaked in water, whereupon the upper end portions projecting above the water surface is deformed, under heat, each into a hemispheric engaging head 12a. Alternatively the male engaging elements 12 having the hemispheric engaging heads 12a may be formed by injection molding. The material of the substrate sheet 11 and the male engaging elements 12 is exemplified by polyamide resin, polyester resin and polypropylene resin. The molded surface fastener 10 of this invention has the elastic layer 13 of polyurethane foamed material laying over the surface of the substrate sheet 11 around the stem portions 12b of the individual male engaging elements 12. The upper surface of the elastic layer 13 is higher than the lower surface of the engaging head 12a of the individual male engaging element 12 and swells outwardly to a middle position of the engaging head 12a, as shown in FIG. 2B. Thus the upper half part of each engaging head 12a projects above the upper surface of the elastic layer 13, while the remaining part of the male engaging element 12 are fully surrounded by the elastic layer 13. The elastic layer 13 may be made of polyurethane resin or other elastic foamed resin. The elastic layer 13 is formed on the surface of the substrate sheet 11 preferably in the following two methods. However this invention should by no means be limited to these illustrated examples. FIGS. 11A, 11B and 11C show the forming procedure of the elastic layer 13 according to a first method. The first method comprises the steps of previously molding the substrate sheet 11 having on one surface the multiplicity of engaging elements 12 (FIG. 11A), applying or ink-jet spraying over the surface of the substrate sheet 11 around the engaging elements 12 a predetermined quantity of foam undiluted solution 13a, such as diisocyanate containing various additives, diluted by a volatile solvent (FIG. 11B), and heating the sprayed surface of the substrate sheet 11 to cause the foam undiluted solution 13a to foam after the solvent volatilizes (FIG. 11C). If the extent to which the foam material is to be expanded in volume by foaming is previously known, the elastic layer 13 may be formed by foaming freely; usually, however, it is foamed, under heat, within a molding die 14 (indicated by a phantom line in FIG. 11C restricting the foaming. If a foam resin material which foams at the normal temperature is used, it may be simply poured into the molding die 14 for foaming inside. FIGS. 12A, 12B and 12C show the forming procedure of the elastic layer 13 and the engaging heads 12a of the engaging elements 12 according to a second method. The second method comprises the steps of previously molding a multiplicity of column-like projections 12c integrally on one surface of a substrate sheet 11 (FIG. 12A), and forming the elastic layer 13 of a predetermined height or thickness on the surface of the substrate sheet 13 around the column-like projections 12c (FIG. 12B). At that time, a predetermined-length upper part of each column-like projection 12c is exposed from the upper surface of the elastic layer 13. For the elastic layer 13, a foamed resin more elastic than the column-like projections 12c and having a higher melting point is selected. The elastic layer 13 is formed likewise the above-mentioned first method. After this forming of the elastic layer 13, the upper ends of the column-like projections 12c exposed from the elastic layer 13 are heated to melt by touching a non-illustrated heating plate so that the hemispheric engaging head 12a is formed on the upper end of each column-like projection 12c. At that time, this deformation is continued until the lower surface of the hemispheric engaging head 12a comes into contact with or slightly penetrates into the upper surface of the elastic layer 13 as shown in FIG. 12C. In the thus manufactured molded surface fastener 10, only the upper surface of the engaging head 12a of each engaging element 12 is exposed on the upper surface of the elastic layer 13, while the stem portion 12b and the lower surface of the engaging head 12a are embedded in the elastic layer 13. Accordingly the stem portion 12b of each engaging element 12 is supported through its entire length by the elastic layer 13 so that its shape is stable during engagement with the companion coupling member and is free from catching a garment, waste pieces of yarn, nap, dust, etc. while it is not in engagement and exposed to the outside. FIGS. 2A, 2B and 3 schematically show the manner in which the molded surface fastener 10 comes into engagement with a companion female engaging member 20. The female engaging member 20 is in the form of a flat plate having a multiplicity of engaging holes 21. As the female engaging member 20 is pressed against the engaging heads 12a of the engaging elements 12 of the molded surface fastener 10, the engaging heads 12a slightly deform and is then inserted through the engaging holes 21. Simultaneously, the elastic layer 13 elastically deforms downwardly between the individual engaging elements 12 to allow the female engaging member 20 to move downwardly. The deformation of the elastic layer 13 may be facilitated by selecting, as the material of the elastic layer 13, a non-adhesive material non-adhesive with respect to the material of the substrate sheet 11 and the engaging elements 12. Assuming that the molded surface fastener is used as, a fastener for fastening interior materials inside a car or a house so that peeling and coupling does not take place repeatedly, the elastic layer 13 is not necessarily non-adhesive with respect to the substrate sheet 11 and the engaging elements 12. Alternatively, foaming of the elastic layer 13 may be terminated when part of the elastic layer 13 comes into contact with only the peripheral edge of the lower surface of the individual engaging head 12a, namely, before touching the whole lower surface of the individual engaging head 12a, so that the molded surface fastener 10 can be coupled with the female engaging member 20 even when pressed by a relatively small force. FIGS. 5 and 6 show a molded surface fastener 100 according to a second embodiment in which hook-shaped engaging elements 120 are substituted for the mushroom-shaped engaging elements 12 of the first embodiment. Also in the molded surface fastener 100, the whole lower surface of a curved locking portion 120a of each hook-shaped engaging element 120 is normally in contact with the upper surface of the elastic layer 13, or the tip of the curved locking portion 120a is normally in contact with or slightly penetrates into the upper surface of the elastic layer 13, as shown in FIGS. 5 and 6. In the case of that the elastic layer 13 is formed to be in contact with the lower surface of the tip of the curved locking portion 120a, as shown in FIG. 5, the surface fastener 100 can be engaged with the companion female engaging member by a relatively small pressing force, as compared to the case of FIG. 6 in which the tip of the curved locking portion 120a is slightly embedded. FIGS. 7 through 9 show examples of companion engaging members to be coupled with the molded surface fastener 10, 100 molded as above and their manners of engagement. In the example of FIG. 7, the surface fastener 10 has the multiplicity of mushroom-shaped engaging elements 12 of the first embodiment, and the companion engaging element has the same structure as that of the surface fastener 10. In the example of FIG. 8, either the male engaging member and the female engaging member is the molded surface fastener 10 of the first embodiment. In the example of FIG. 8, adjacent curved locking portions 120a are urged in the engaging directions due to the elasticity of the elastic layer 13 as compressed to deform by the hook-shaped engaging elements 120, causing an improved degree of engaging force. In the example of FIG. 9, the male engaging member is the molded surface fastener 100 having the above-described hook-shaped engaging elements 120, while the companion female engaging member is a female surface fastener 200 having loops 210. In this example, in order to increase the rate of engagement with the female surface fastener 200, it is preferable that the tip of the curved locking portion 120a of each hook-shaped engaging element 120 is normally in slight contact with the upper surface of the elastic layer 13 and that the elastic layer 13 is made of a non-adhesive material non-adhesive with respect to a substrate sheet 110 and the engaging elements 120. FIG. 10 shows a third embodiment in which the molded surface fastener 10, 100 of each of the foregoing embodiments is substituted by a surface fastener 10' woven or knitted of fiber threads or monofilaments. In the third embodiment, engaging elements 12' are made of a monofilament; firstly, the monofilament is woven or knitted in loops in a woven or knit foundation structure during the weaving or knitting of the foundation structure, whereupon upper ends of the individual loops are cut off and then each upper end is deformed into a hemispheric engaging head 12a'. The engaging head 12a' may be formed in an alternative known method. As is apparent from the foregoing description, the surface fastener 10, 100 of this invention is easy to manufacture. Further, partly since the stem portion 12b, 12b', 120b of the individual engaging element 12, 12', 120 is supported through substantially the entire surface by the elastic layer 13, and partly since the lower surface of the locking portion 12a, 12a', 120a is normally at least in contact with the upper surface of the elastic layer, the engaging elements are adequately stable in shape. Furthermore, since the engaging elements 12, 12', 120 are free from catching waste pieces of yarn, nap, etc. even when the engaging surface of the surface fastener 10, 100 comes into contact with a garment, it is possible to guarantee a neat appearance and an adequate degree of engaging force for a long period of time with repeated use.	A surface fastener comprising: a substrate sheet; a multiplicity of engaging elements projecting from on surface of the substrate sheet; and an elastic member laying over the one surface of the substrate sheet. The elastic member has an upper surface normally in contact with lower ends of locking portions of the engaging elements so as to support circumferential surfaces of stem portions of the engaging elements. The upper surface of the surface fastener is therefore less rough so that waste pieces of yarn and nap cannot be caught by the locking portions.	8
CROSS-REFERENCE To RELATED APPLICATIONS [0001] This application claims priority to U.S. Provisional Patent Application 60/440,175 filed Jan. 15, 2003, and incorporates the contents in its entirety. FIELD OF THE INVENTION [0002] The present invention relates to a system and method for treating snoring, and more particularly methods for determining anatomical structures implicated in snoring and using implantable microstimulators to treat snoring. BACKGROUND [0003] Snoring can be defined as noisy respiratory sounds while sleeping. People who snore do not usually make snoring sounds when breathing awake in the same posture that is associated with snoring when asleep. That is because the awake person has conscious control of various muscles whose mechanical action tenses and shapes the upper airway so as to prevent the vibrations that cause snoring to occur. During sleep, the motor neurons that control most skeletal muscles are inhibited from sending commands to activate those muscles. The resulting flaccid muscle tone permits soft tissue to sag into the airway and consequently snoring to occur. [0004] Snoring may also occur because the airway is constricted, creating turbulence, and/or when the soft tissues are unusually large, soft and easily vibrated. Snoring is particularly common and severe in males, older people, and obese people, but it can occur in virtually anyone. Predisposing factors include obesity with accumulation of adipose tissue in the airway and congenital narrowing of the upper airway. Snoring may occur in any position but is most pronounced when sleeping in a supine position in which gravity causes soft tissues to fall against the back of the airway. [0005] The sounds of snoring are generated by vibration of soft tissues in the upper airway, such as the soft palate, uvula, tongue, lips, posterior and lateral pharyngeal wall and epiglottis. However, the soft palate and uvula are most commonly implicated. [0006] Many treatments for excessively loud snoring have been proposed, but few are in common use because of various disadvantages and limitations in effectiveness. Treatments include mechanical devices to control body posture, mechanical appliances worn in the mouth and on the jaw, electrical stimulators applied to the mucosa of the oral cavity, surgical remodeling of the oropharynx, sound detectors to awaken the offending snorer, and acoustic cancellation techniques to reduce the sounds heard by companions. Many of these techniques have only limited effectiveness or are applicable only to certain sources of snoring. Those that are effective have various disadvantages that include physical discomfort, interference with the normal sleep of the patient and reoccurrence of snoring over time. [0007] Muscles can be electrically stimulated artificially to contract directly or indirectly by activating the neurons that innervate them. Such stimulation has been applied to reanimate paralyzed limbs, but it has not been feasible to apply to oropharyngeal muscles with the previously available technologies. Stimulation of limb muscles has been accomplished by applying transcutaneous electrodes to the surface of the skin, by inserting percutaneous wires into the muscles and by surgically implanting electrodes in or on muscles and nerves, which electrodes are connected by leads to a central stimulus pulse generator similar to a cardiac pacemaker. More recently, wireless microstimulators have become available that are small enough to be injected into the body where they receive electrical power and/or command signals by inductive coupling from a radio-frequency electromagnetic field generated outside the body. [0008] The muscles of the oropharynx and their motor nerves are small and difficult to access surgically. Electrical stimulation pulses applied to the muscles transcutaneously via the mucosa of the oropharynx causes unpleasant sensations as a result of activation of its many sensory nerve endings. [0009] While snoring may not wake the subjects themselves, it is often very problematic because the noise disturbs the sleep of others in the vicinity, such as a spouse or roommate. Therefore, effective methods and devices for the treatment of snoring are desirable. SUMMARY OF THE INVENTION [0010] The present invention may include a method for treating snoring comprising monitoring the airway passage of a patient during sleep to identify at least one anatomical structure in the airway passage that vibrates during snoring; implanting at least one microstimulator in the proximity of at least one anatomical structure in the airway passage that vibrates during snoring; and energizing the microstimulator to deliver an electrical stimulation to the anatomical structure to cause at least one muscle to contract and reduce the vibrations of the airway passage. [0011] The invention may also include inserting a distal end of a scope such that the distal end is located in an upper airway of the patient and monitoring the airway passage during sleep. [0012] The invention may also include inserting a distal tip of an insertion tool into the anatomical structure, wherein the microstimulator is located in a lumen of the insertion tool, and activating the insertion tool to eject the microstimulator from the insertion tool, and removing the insertion tool from the anatomical structure. [0013] The invention may also include delivering an electrical stimulation to the anatomical structure prior to implantation and observing the anatomical structure for a decrease in vibration. [0014] The invention may also include inserting a distal tip of an insertion tool into an anatomical structure, applying an electrical current to at least the distal tip of the insertion tool, and delivering an electrical current to the anatomical structure. [0015] The invention may also include inserting a distal tip of an insertion tool into the anatomical structure, wherein the microstimulator is located in a lumen of the insertion tool, and energizing the microstimulator located within the lumen of an insertion tool. [0016] The invention may also include testing the microstimulator by emitting electrical stimulations at a plurality of intensities, and observing the anatomical structure to determine the intensity which decreases the vibration of the anatomical structure. The present invention may further include a method wherein the electrical stimulation is of an intensity from about 8 to about 800 nC. [0017] The present invention may further include energizing the microstimulator at a selected frequency to deliver an electrical stimulation to the anatomical structure to cause at least one muscle to contract and reduce the vibrations of the airway passage. The present invention may further include a method wherein the frequency is about 1 to about 30 pulses per second. [0018] The present invention may further provide interruptions of a selected duration and period in the electrical stimulation to permit the at least one muscle to relax. The present invention may further include a method wherein the duration of the interruption is from about 0.2 to about 2 seconds and the selected period is from about 5 to about 20 seconds. [0019] The present invention may further comprise sensing when snoring is occurring; and generating an electrical stimulus from the microstimulator to contract an oropharyngeal muscle, in response to sensing snoring. The present invention may further sense snoring by detecting mechanical vibrations or acoustically detecting sounds generated by vibrating at least one anatomical structure in the airway passages. [0020] The present invention may further include a method wherein the energizing includes delivering a control signal to a pair of electrodes, wherein the microstimulator includes the pair of electrodes. [0021] The present invention may further include a method wherein the anatomical structure is selected from the group comprising the soft palate or the uvula. The present invention may further include a method wherein the anatomical structure is a muscle selected from the group comprising: palatoglossus, palatopharyngeal, musculus uvulae, genioglossus, geniohyoid, levator palati or tensor palati. The present invention may further include a method wherein the anatomical structure is a branch or terminal of a nerve selected from the group comprising: vagus X, hypoglossal, vagus pharyngeal branch, V3 branch trigeminal nerve. [0022] The invention may further comprise implanting a second microstimulator proximate to at least a second anatomical structure, different from the at least one anatomical structure. The present invention may further include a method wherein at least one anatomical structure and a second anatomical structure are muscle pairs selected from the group comprising: geniohyoid and genioglossus; tensor palati and palatoglossus; tensor palati and musculus uvulae. [0023] The present invention may further include a method wherein at least one of the microstimulators includes a sensor and a telemeter configured to generate a signal indicative of a sensed condition, and at least one of the microstimulators includes a circuitry configured to generate an electrical stimulation pulse. [0024] The present invention may further include a method of treating snoring comprising implanting a microstimulator within at least one of the soft palate or the uvula; and activating the microstimulator to deliver an electrical stimulation to at least one of the soft palate or the uvula to cause at least one muscle to contract. [0025] The present invention may further include a method wherein the microstimulator includes an electrical circuit configured to generate an electrical stimulus and a pair of electrodes configured to apply the electrical stimulus to the at least one of the soft palate or uvula. The present invention may further transmit from a controller to the microstimulator power, control signals, or power and control signals. [0026] The present invention may further transmit an acknowledgement signal from the microstimulator to a controller, wherein the acknowledgement signal indicates that the microstimulator has received a control signal from a controller. [0027] The method of the present invention may further activate the microstimulator in a temporal pattern to deliver the electrical stimulation to at least one of the soft palate or the uvula to cause at least one muscle to contract, wherein the temporal pattern includes periods of an absence of electrical stimulation to permit the at least one muscle to cease from contracting. [0028] The method of the present invention may further test the microstimulator by emitting electrical stimulations at a plurality of intensities, and observe at least one of the uvula or soft palate to determine the intensity which decreases the vibration of the uvula or soft palate. The present invention may further include a method wherein the electrical stimulation is of an intensity from about 8 to about 800 nC. [0029] The method of the present invention may further comprise sensing when snoring is occurring; and electrically stimulating the at least one microstimulator implanted within the soft palate or the uvula in response to sensing snoring. [0030] The present invention may further include a method wherein the microstimulator is implanted in a muscle selected from the group comprising: palatoglossus, palatopharyngeal, or musculus uvulae. The present invention may further include a method wherein the microstimulator is implanted proximate to a branch or terminal of the vagus X nerve. The method of the present invention may further implant a second microstimulator in the proximity of an anatomical structure selected from the group comprising: palatoglossus, palatopharyngeal, musculus uvulae, genioglossus, geniohyoid, levator palate, tensor palati, vagus X, hypoglossal, vagus pharyngeal branch, V3 branch trigeminal nerve. [0031] The method of the present invention may further insert a distal tip of an insertion tool including a microstimulator through the oral mucosa of the soft palate; insert the distal tip of the insertion tool into the uvula; activate the insertion tool to deposit the microstimulator from the insertion tool; and remove the insertion tool from the uvula. The method of the present invention may further include positioning the microstimulator in or in the proximity of the musculus uvulae. The method of the present invention may further include positioning the microstimulator in the proximity of the terminal branches of the motor axons to the musculus uvulae, wherein the microstimulator includes a cathode and an anode; and positioning the microstimulator cathode in the proximity of the terminal branches of the motor axons to the musculus uvulae. [0032] The method of the present invention may further comprise advancing a distal tip of an insertion tool through the oral mucosa to the soft palate to the uvula, wherein the distal tip of the insertion tool includes a microstimulator within a lumen of the distal tip; and testing microstimulator by emitting electrical stimulation from the microstimulator within the lumen of the distal tip; and withdrawing the insertion tool leaving the microstimulator within the uvula. [0033] The invention may further include a method of implanting a microstimulator into the genioglossus muscle comprising inserting a distal tip of an insertion tool through the epidermis under the mandible; passing the distal tip of the insertion tool through the geniohyoid muscle; inserting the distal tip of the insertion tool into the genioglossus muscle; depositing the microstimulator in the genioglossus muscle; and e) removing the insertion tool from the uvula. [0034] The method of implanting a microstimulator in the genioglossus may further include positioning the microstimulator in the proximity of the endplate zone of the radially oriented sagittal muscle fibers of the genioglossus muscle or the hypoglossal nerve, wherein the microstimulator includes a cathode and an anode; and positioning the microstimulator cathode in the proximity of the endplate zone of the radially oriented sagittal muscle fibers of the genioglossus muscle or the hypoglossal nerve. [0035] The method of implanting a microstimulator in the genioglossus may further comprise advancing a distal tip of an insertion tool through the geniohyoid muscle to the genioglossus muscle, wherein the distal tip of the insertion tool includes a microstimulator within a lumen of the distal tip; and testing microstimulator by emitting electrical stimulation from the microstimulator within the lumen of the distal tip; and withdrawing the insertion tool leaving the microstimulator within the genioglossus. [0036] The method of the current invention may include treating snoring in a patient comprising alternately stimulating at least a first and second muscle in the oropharynx to contract so that an airway passage remains substantially free of vibrating soft tissue during sleep. The present invention may further include a method for treating snoring in a patient comprising alternately stimulating at least a first and second muscle in the oropharynx to contract so that an airway passage remain substantially free of vibrating soft tissue during sleep, and selecting a pattern of stimulation such that while the first muscle is being contracted the second muscle may have a period of relaxation, and while the second muscle is being contracted, the first muscle may have a period of relaxation. The method of present invention may further include implanting at least a first microstimulator and a second microstimulator, and wherein the first and second microstimulators are alternately activated to cause the contraction of the at least first and second muscle in the oropharynx. [0037] The present invention may further include a method for treating snoring wherein the first and second muscles are selected from the group comprising: palatoglossus, palatopharyngeal, musculus uvulae, genioglossus, geniohyoid, levator palati, tensor palati. The present invention may further include a method for treating snoring wherein the first and second muscles are selected from the groups of pairs comprising: tensor palati and palatoglossus; tensor palati and musculus uvulae; and geniohyoid and genioglossus. [0038] The method of the present invention may further comprise applying electrical stimulations for a selected duration to stimulate at least the first muscle in the oropharynx to contract, and interrupting the electrical stimulation for a selected duration at a selected period to permit the first muscle in the oropharynx to relax. [0039] It is an object of the invention to prevent or reduce the frequency or severity of snoring by causing at least one muscle to contract, producing force or motion to retract soft tissues of the oropharynx from the airway. [0040] It is a further object of the invention to employ electrical stimulation of at least one nerve or muscle to achieve muscle contraction in the oropharynx. [0041] It is yet another object of the invention to provide fully implanted microstimulators in or near at least one muscle or nerve to deliver electrical stimulation in the region of the oropharynx. [0042] It is an additional object of the invention to provide wireless or leadless microstimulators that receive electrical power and/or control signals from a control unit located outside of the body. [0043] It is an additional object of the invention to provide a microstimulator in a size and form that permits it to be injected into or near the muscles or nerves of the oropharynx. [0044] In one embodiment, the invention uses miniature, single channel, wireless electrical stimulators injected into or near small muscles so as to selectively activate them to contract and prevent snoring. [0045] A variety of anatomical structures in the oropharynx may contribute to snoring sounds and there are many separately innervated small muscles whose tone affects the position of these anatomical structures relative to the airway. It is therefore an object of the present invention to have a suitable methodology to identify the site where snoring originates in order to decide which nerve(s) and/or muscle(s) may be stimulated to reduce the frequency or severity of snoring. A flexible scope, such as a fiber optic scope may be used in one embodiment of the invention to identify the anatomical structure(s) involved in the generation of the snoring sounds and to determine the appropriate nerve(s) and/or muscle(s) and parameters of electrical stimulation required to reduce or eliminate the snoring. [0046] Once a microstimulator has been implanted, there are stimulation parameters that may be selected for maximum effectiveness (e.g., pulse intensity, frequency, and on/off patterns). It is one object of the invention to monitor the oropharynx to determine the effects of selected stimulation and to direct the selection of an appropriate program of stimulation effective in reducing the frequency or magnitude of snoring. BRIEF DESCRIPTION OF DRAWINGS [0047] [0047]FIG. 1 is a schematic drawing depicting one position of a microstimulator and one method in which a microstimulator may be used to treat snoring; [0048] [0048]FIG. 2 is a sagittal view of the head demonstrating the location of a variety of anatomical structures implicated in snoring, as well as depicting at least two insertion approaches for the implantation of a microstimulator according to the present invention. [0049] FIGS. 3 A-D are schematic drawings depicting muscles near or in which microstimulators may be implanted to treat snoring; A) is a frontal view of muscles of the soft palate; B) is a cross-sectional view of the auditory tube and surrounding muscles; C) is a frontal view of the side walls of the pharynx; D) is a cross-sectional view of the pharynx. [0050] [0050]FIG. 4 is a schematic drawing depicting one method in which a subject may be monitored to evaluate the selection of an anatomical location, implantation of a microstimulator and modification of parameters of electrical stimulation to treat snoring; [0051] [0051]FIG. 5A is a schematic drawing depicting one embodiment of a microstimulator which may be useful in the invention; FIG. 5B depicts one embodiment of an injection device which may be useful in the present invention; FIG. 5C depicts one method of using an injection device to implant a microstimulator. DETAILED DESCRIPTION OF THE INVENTION [0052] In one embodiment of the invention, at least one microstimulator 10 may be used to contract select muscles of the oropharynx 100 to decrease or eliminate the vibration of tissues along the airway passages 102 in patients who snore. [0053] Location of implantation. FIG. 1 is a schematic drawing depicting one position of a microstimulator 10 and one method in which a microstimulator may be used to treat snoring. In one embodiment of the invention, a microstimulator 10 may be implanted and activated so that it causes the contraction of at least one muscle in the oropharynx 100 creating force or motion to retract soft tissue from the airway passages 102 . The oropharynx includes at least the oral cavity and pharynx, and anatomical structures therein. The airway passages 102 include the pathway that air travels between the mouth/nose and the lungs during inhalation and exhalation. More particularly the airway passages 102 are created by the inner lumen of the oral and nasal cavities, as well as the pharynx and trachea. [0054] [0054]FIG. 2 is a sagittal view of the head demonstrating the location of a variety of anatomical structures implicated in snoring, as well as depicting at least two insertion approaches for the implantation of a microstimulator according to the present invention. The uvula 104 , soft palate 106 , tongue 108 , lips 110 and posterior and lateral pharyngeal wall 112 and 114 and epiglottis 116 all may participate, although the uvula 104 soft palate 106 and are most commonly implicated in snoring. [0055] In one embodiment of the invention, the at least one microstimulator 10 may be implanted in or near the uvula 104 or soft palate 106 as illustrated in FIG. 1. These anatomical sites contain muscle fibers that are innervated by motor neurons whose axons course through them. The axons of motor neurons may have a much lower threshold for electrical excitation than muscle fibers and each motor axon is connected to and may activate a large number of muscle fibers in the target muscle. In one embodiment of the invention, stimulation parameters may include a pulse width of 20-200 μs and a pulse current of 0.4-4.0 mA. Stimulation parameters may be varied depending on how close to the motor axons the microstimulator has been implanted. The intensity of an electrical stimulation pulse with these ranges of parameters is approximately related to the charge of the pulse, which is the product of pulse width and current (e.g., 1 mA×100 μs=100 nC). [0056] The stimulation parameters may be selected such that the intensity of the pulse is effective in causing at least a muscle twitch. The stimulation parameter may be selected as the minimum effective intensity. This may be advantageous at least in that due to the small size of these anatomical sites and their coverage with mucosal tissue that contains sensory nerve fibers, it is advantageous to avoid producing sensations that might awaken the sleeping subject. [0057] FIGS. 3 A-D are schematic drawings depicting muscles near or in which microstimulators may be implanted to treat snoring; A) is a frontal view of muscles of the soft palate; B) is a cross-sectional view of the auditory tube and surrounding muscles; C) is a frontal view of the side walls of the pharynx; D) is a cross-sectional view of the pharynx. [0058] If the vibrations associated with snoring appear to be associated with the uvula 104 and soft palate 106 , one site of microstimulator implantation is in the distal soft palate 106 at the base of the uvula 104 near the musculus uvulae 132 (or uvular muscle; having an origin at the palatal aponeurosis and hard palate; insertion: soft tissue of uvula; innervation: unknown presumed branch of vagus; See FIGS. 6 A-D) that elevates the uvula. This function is variable in some individuals. When they say “Ah,” the uvula shrinks in length to less than one-half original size with pronounced horizontal ridges. In others, the uvular muscle does not seem to contract and all elevation appears to be due to action of levator palati. Implantation may also or alternatively be at or near palatal muscles, such as the palatoglossus 130 (having an origin at the palatal aponeurosis; insertion at the base of the tongue; innervation by the vagus X; See FIGS. 3A and D) which depresses soft palate; or the palatopharyngeus 136 having subparts including a: 1) palatopharyngeal portion 136 a (having an origin at the palatal aponeurosis; insertion at the lamina of thyroid cartilage; innervation: vagus X; See FIGS. 3C and D) that depresses palate during inhalation with mouth closed and assists stylopharyngeus muscle in laryngeal elevation when swallowing; and [0059] 2) salpingopharyngeal portion 136 b (having an origin at the posterior lamina of cartilaginous eustachian tube; insertion: fuses with palatopharyngeal portion to insert on thyroid lamina; innervation by the vagus X; See FIGS. 3C and D) presumed to assist in laryngeal elevation, but may also have a role in eustachian tube function. All of the above-noted muscles may both stiffen and change the shape of the upper airway. Both of these actions may be useful to reduce snoring, depending on the source of the vibrations producing the sound and the selection of the neuromuscular site or sites that are stimulated. Methods to identify which of these sites is most likely to be useful in a given subject are described below. [0060] An alternative site of implantation may be at or near the branches or terminals of the vagus X nerve which innervates musculus uvulae 132 , palatoglossus 130 and the palatopharyngeus 136 . [0061] As shown in FIG. 2, the implantation of a microstimulator near the uvula 104 or soft palate 106 may be accomplished by anesthetizing the soft palate mucosal surface 118 and passing an insertion tool 36 into the base of the uvula 104 along the line A indicated by the arrow in FIG. 2 that points to the musculus uvulae 132 . The microstimulator may be positioned such that the cathodal stimulating electrode 14 or 16 may be positioned near the terminal branches of the motor axons to the musculus uvulae 132 and/or palatoglossus 130 and the palatopharyngeus 136 , respectively. [0062] Stimulating these motor axons causes the muscle fibers that they innervate to contract. The effect is to withdraw the uvula 104 and or soft palate 106 from the respiratory airflow 102 and/or stiffen the distal soft palate 106 , hence reducing or eliminating vibration. [0063] If the vibrations are associated with the tongue 108 , the microstimulator 10 may be implanted in the posterior portion of the tongue 108 in the sagittal plane. As shown in FIG. 2, this implantation can be accomplished by passing an insertion tool 36 from under the mandible 122 , through the geniohyoid muscle 124 and into the genioglossus muscle 126 , along the line B indicated by the arrow in FIG. 2 that points to the genioglossus muscle 126 . The microstimulator's 10 cathodal stimulating electrode 14 or 16 may be located close to the endplate zone of the radially oriented sagittal muscle fibers. [0064] The resulting protrusion of the tongue lifts it away from the soft tissues of the posterior and lateral pharynx 112 / 114 , opening the airway passages 102 . The approach of injecting the microstimulator via this route (as opposed to into the tongue through the mucosal surface) may be advantageous at least in that 1) it is easier to anesthetize the entry point for the insertion tool, 2) easier to stay on midline to target tongue protrusor motor units and avoid injury to nerves and blood vessels, easier to observe the effects of test stimului on the tongue motion before releasing a microstimulator in situ, less chance of contaminating the insertion tool and microstimulator with bacteria from the oral cavity. The muscle fibers of the tongue are organized into functionally and anatomically distinct groups based on their position and orientation within the tongue. The posteriorally directed portion of the parasagittal fan of muscle fibers originates from the mandible and produces tongue protrusion. Endplate bands innervate the midpoints of these fibers and extend to the midline. Therefore, a microstimulator may be placed in the in the midplate near the endplates to produce symmetrical protrusion of the tongue. [0065] In one embodiment, the microstimulator may be implanted in the proximity of the hypoglossal nerve. The hypoglossal nerve branches to the genioglossus 126 and enters the tongue inferolaterally, longitudinally and radially in order to innervate various of the functionally distinct groups of muscle fibers in the tongue. It is difficult to predict the net motion that will result from stimulation of the hypoglossal nerve because it depends on the relative activation of these functionally distinct groups. Nevertheless, any activation of the muscle fibers will increase the mechanical stiffness of the tongue, reducing its tendency to vibrate as air passes by it. [0066] If the vibrations are associated with the posterior and/or lateral pharyngeal walls 112 / 114 , then stimulation of the genioglossus muscle 126 may be effective, even though the resulting muscle contractions do not directly effect the tissues of the posterior and lateral pharynx 112 / 114 whose vibrations are the source of the snoring. Rather, protrusion of the tongue generally increases the cross-sectional area of the airway passages 102 , reducing the local velocity of airflow, in turn reducing the tendency of the adjacent tissues to vibrate and produce turbulence and snoring. [0067] The microstimulator 10 may be implanted in the geniohyoid muscle 124 itself, whose action tends to increase the diameter of the oropharyngeal airway passages 102 . If this is desired, then the microstimulator can be implanted along line B of FIG. 2, but more superficially in the geniohyoid muscle 124 itself. [0068] Further, a microstimulator 10 could be positioned so that one each of its two electrodes 14 / 16 lies within one each of the geniohyoid 124 and genioglossus muscle 126 , respectively. In this embodiment, it may be possible to stimulate both muscles simultaneously with sufficiently strong stimulation pulses. [0069] Snoring originating from the epiglottis 116 tends to be associated with respiratory sounds in young infants in which the epiglottis has not yet developed sufficient stiffness in its cartilage. This cause of snoring usually resolves spontaneously. However, if snoring persists through development, a microstimulator may be implanted in any muscle or adjacent to any nerve innervating a muscle whose contraction may move the epiglottis out of the airway during sleep. The position of the microstimulator relative to the epiglottis should be carefully selected so as to not interfere with the normal functioning of the swallowing reflex. [0070] Applicants have also found that snoring in at least some patients may result from inappropriate action of the palate elevator muscles during sleep that shifts the uvula 104 and soft palate 106 actively, but briefly, into the airway passages 102 . For example, levator palati 134 (or levator veli palatine; having an origin at the apex of the petrous bone descending to the palate along the floor of the eustachian tube; insertion at palatal aponeurosis; innervation: pharyngeal branch of vagus nerve X; See FIGS. 3 A-D) elevates the soft palate 106 , such as when a patient says, “Ah!”. Also, the tensor palati 128 (or tensor palatini, tensor veli palatine; having an origin at the scaphoid fossa of sphenoid bone an area lateral to base of medial pterygoid plate; insertion: muscle fibers descend vertically form a tendon which wraps around hamulus bone then insert about horizontally onto palatal aponeurosis; innervation by the trigeminal nerve V (V3 branch); See FIGS. 3 A-D) tenses the palate. Microstimulator implantation in or near the levator palati 134 and/or tensor palati 128 is expected to be effective in overcoming motion that shifts the uvula 104 and soft palate 106 into the airway passages 102 . This finding emphasizes the importance of direct visualization of the oropharynx to identify correctly the site and cause of snoring and to adjust the stimulation parameters of the implanted microstimulator(s) to counteract it effectively. [0071] As above, the microstimulator may be implanted in the proximity of the branch or terminals that innervate the levator palati 134 or the tensor palati 128 , including the pharyngeal branch of vagus nerve or the trigeminal nerve V (V3 branch), respectively. [0072] For all implantation sites, the position of the microstimulator 10 with respect to both the neuromuscular targets and the sensory innervation of the oropharynx should be considered. If the microstimulator 10 tends to activate sensory nerves at lower stimulus thresholds than those for the desired neuromuscular activation, the patient will experience disagreeable sensations that are likely to interfere with sleep. The microstimulator 10 and the insertion tool 36 used to implant them may therefore be selected to have: 1) a small size relative to the implantation site; 2) permit orientation specific placement relative to the implantation site; 3) permit application of test stimulation pulses during the implantation process and 4) allow the minimum effective stimulation parameters to be determined. [0073] For all implantation sites, the microstimulator implant may be oriented more or less vertically when the patient sleeps in the supine posture. This positioning facilitates transmission of power and/or command signals to the microstimulator 10 from an external controller 24 , including components such as a transmission coil 20 located in the pillow 18 under the head, as illustrated in the cross-section in FIGS. 1 and 4. In this orientation, the axes of the transmission coil 20 and a receiving coil located inside the microstimulator electronic subassembly 12 may be aligned coaxially, which increases the coupling coefficient between them. [0074] When the microstimulator 10 is implanted within a muscle, it may be positioned within the belly of the muscle in which contraction is desired. This may be advantageous at least in: 1) permitting the selective activation of the desired muscle; 2) reducing inadvertent excitation of other, nearby nerves and muscles and 3) reducing migration after implantation to an inappropriate location or position. [0075] Plurality of microstimulators. The number and location of microstimulators 10 implanted may depend on the nature of the underlying pathophysiology of the snoring, as discussed. In one embodiment, the size of the microstimulator is selected so that they are small enough that at least two can be placed at different locations within the same muscle, where they will recruit largely non-overlapping populations of motor units. In one embodiment, the microstimulators are individually addressable and/or can be separately commanded to produce a desired pattern of stimulation pulses to achieve relief from snoring. [0076] A plurality of microstimulators may be implanted in the oropharynx, such as one in each of any of positions described. By way of example, one microstimulator may be implanted in each of the geniohyoid 124 and genioglossus muscles 126 . By way of further example, one microstimulator may be implanted in each of the tensor palati 128 and palatoglossus 130 muscles. By way of further example, one microstimulator may be implanted in each of the tensor palati 128 and musculus uvulae 132 or in other combinations involving other sites as identified above. A microstimulator may also be placed at or near the oropharynx generally to serve a detection function, described below. [0077] Those skilled in the art and familiar with the neuromuscular anatomy of the upper airway passages 102 would understand that implanting microstimulators at locations other than the ones depicted in the figures may aid in the treatment of snoring. [0078] Microstimulators. In order to treat snoring by the methods taught in this invention, implanted devices may be used that are small enough to inject into the subject through a hypodermic needle, that require no physical connection to a source of power or command signals, and that can be controlled to produce stimulation pulses whose strength and timing can be adjusted to meet the needs of the subject. The function, form and detailed design of microstimulators that may be useful in this invention have been described in detail in U.S. Pat. Nos. 5,193,539, 5,193,540, 5,312,439, 5,324,316, 5,405,367, 6,051,017, 6,175,764, 6,181,965, 6,185,455, 6,214,032, 6,240,316, the contents of which are incorporated herein by reference. [0079] The microstimulator 10 for use in the present invention may be a wireless miniature device that can be implanted in or near a target muscle or nerve without requiring leads for electrodes, power or command signals. For example, a BION® (BIONic Neuron, Advanced Bionics Corp., Valencia, Calif.) may be used as a microstimulator in this invention. BIONs® are single channel, wireless (leadless) microstimulators (about 16 mm long×2 mm in diameter) that can be injected in or near muscles or nerves. Each microstimulator may receive power and digital command data via an external controller 24 including an RF transmission coil 20 to produce stimulation pulses with a selected intensity and pattern. Each microstimulator may receive the RF energy and convert it into an AC or DC supply to operate an integrated circuit chip, and store pulse energy in a capacitor. The microstimulator may receive command data, and generate a stimulation pulse releasing energy stored in a capacitor, then recharge a capacitor between output pulses. [0080] [0080]FIG. 5A is a schematic drawing depicting one embodiment of a microstimulator 10 which may be useful in the invention. The size of the microstimulator 10 may be selected so as to minimize tissue damage at the selected site of implantation, minimize discomfort, minimize normal activity of the muscle/nerve in or near which the microstimulator is implanted. As shown in FIG. 5A, each microstimulator 10 may consist of three elements: electronic subassembly 12 and at least two electrodes 14 and 16 (e.g., one anode and one cathode for the application of stimulation current to surrounding tissue). The microstimulator electronic subassembly 12 may include a power source and/or control system for regulating parameters of electrical stimulation. Alternatively, the power source and/or control system may reside outside of the microstimulator 10 , and even outside of the body in the controller 24 . [0081] [0081]FIG. 1 is a schematic drawing depicting one position of a microstimulator 10 and one method in which a microstimulator 10 may be used to treat snoring. For example, in one embodiment, the microstimulator 10 may include an electronic subassembly 12 which may receive power and/or command signals by inductive coupling from an external controller 24 , including an antenna/transmission coil 20 located outside the body. The electronic subassembly 12 may also store electrical power within the microstimulator. In some embodiments, the transmission coil 20 may be housed within a structure 18 , such as a pillow which may be positioned in a suitable location, such as under the patient's head 120 to guarantee physical proximity to the implanted microstimulator 10 . The transmission coil 20 may be energized with a radio frequency electrical current generated by a driver 22 and modulated according to a stimulation parameters that have been loaded into a digital memory contained within a controller 24 . [0082] Battery operated. In another embodiment, a miniature power storage component may be incorporated into each microstimulator 10 , such as a miniature rechargeable lithium cell, plus electronic means to store and execute stimulus parameters and the desired temporal pattern of successive stimulus pulses, such as an electronically erasable and programmable read-only memory. This approach is well-described in the prior art, such as U.S. Pat. Nos. 6,185,452 and 6,240,316, the content of which is incorporated herein by reference. Such internally powered microstimulators 10 may be capable of autonomous generation of the temporal pattern of stimulation treatment even if the microstimulator 10 is not proximate to a transmission coil 20 , for example. Because the storage capacity of a miniature power storage component within the microstimulator 10 may be limited, the microstimulator 10 may also use power transmitted from transmission coil 20 whenever available to reduce demand on the power storage component and to recharge it back to its capacity. Transmission coil 20 or another command and/or power transmission device can be used to command microstimulators 10 to begin or cease such autonomous operation, such as when the patient goes to bed or arises or begins snoring. [0083] The stimulation parameters may constitute a string of command signals. Each command signal may contain digital data identifying the address of a selected microstimulator 10 that is to generate selected electrical stimulation pulses, the pulse intensity, frequency and on/off duty cycle patterns required to evoke the desired muscle contraction. Stimulation parameters may include parameters will generally lie in the ranges including but not limited to about 10-1000 nC, about 1-30 pps, and about 20-100% duty cycle. [0084] The microstimulator 10 may be modular design in design and individually and discretely addressable since this design would permit additional channels of stimulation to be added to the patient at any time without interfering with those channels installed previously. [0085] In one embodiment, the microstimulator may provide electrical stimulation to muscles of the oropharynx only when snoring is detected. For example, as shown in FIG. 1, a detector 26 , such as a microphone, may be placed near the patient; detect the sounds of snoring; and convey them to controller 24 to act as a trigger signal. An acoustic signal processing algorithm in controller 24 may determine if the detected sounds are actually snoring (as opposed to other ambient sounds) and may initiate a predetermined pattern of stimulation consisting of one or more cycles similar to that described above. [0086] In one embodiment, a microstimulator 10 may be used as a sensor 26 function. For example, a microstimulator may be used to detect vibrations of the oropharynx during sleep, detect volume, or the tone of the muscle in which it is implanted. Such vibrations could be detected by a microminiature accelerometer fabricated according to MEMS (Micro Electro Mechanical Systems) technology, which is well-known in the art, examples of which are described in “Highly Symmetric Tri-axis Piezoelectric Bimorph Accelerometer,” by Qiang Zou, Wei Tan, Eun Sok Kim and Gerald E. Loeb, to be published in 17 th IEEE Conference on Micro Electro Mechanical Systems (MEMS 2004), IEEE, 2004 (4 pp.), and incorporated herein by reference. The data may be used by the same microstimulator 10 to initiate an electrical stimulation. The data may be telemetered on a carrier frequency directly to another microstimulator 10 to cause an electrical stimulation. The data may be telemetered to a receiving coil 20 . The detection data may be conveyed to a controller 24 , which utilizes the information to decide what and when stimulation is required to alleviate the snoring. One means of transmitting data from one microstimulator 10 to receivers of such data is by “suspended carrier transmission” as described in U.S. Pat. No. 5,697,076 and incorporated herein in reference. [0087] Implantation by Injection Device. The microstimulators 10 may be of a size and shape to be implantable by injection. Injection of a microstimulator may be by insertion at the selected anatomical site for example, through the lumen of an insertion tool 36 , such as a flexible tube, a rigid hypodermic needle or a laparoscopy tool. An insertion tool 36 and method of implantation of a microstimulator may be used such as described in “Cargo Delivery Capsule” U.S. Provisional Patent Application 60/476,007 filed Jun. 4, 2003 or “Injection Devices and Methods for Testing Implants Prior to Positioning” U.S. Utility application Ser. Nos. 10/461,560 or 10/461,132 filed Jun. 12, 2003. [0088] The insertion tool 36 used in the implantation of a microstimulator may be selected to permit site-specific and orientation specific placement of the microstimulator 10 at the selected anatomical location. Further, the insertion tool 36 may be designed to permit the testing and/or repositioning of a microstimulator 10 at the selected anatomical location prior to release from the insertion tool 36 . The insertion tool 36 may be designed to minimize damage to the microstimulator 10 , as well as minimize tissue damage, risk of infection and patient discomfort during the implantation procedure. [0089] [0089]FIG. 5B depicts one embodiment of an insertion tool 36 which may be useful in the present invention. The insertion tool 36 may include a plastic sheath 38 around a removable metal trochar 40 . Trial electrical pulses can be applied through the trochar 40 to identify the desired target for implantation. The trochar 40 may then be removed from the sheath 38 and the microstimulator 10 injected through the distal most tip of the sheath 38 into the site. FIG. 5C depicts one method of using an injection device to implant a microstimulator. [0090] Methods of use. The best anatomical site(s) for implantation of microstimulators and the parameters of stimulation to alleviate snoring may be difficult to determine in a given patient. [0091] Monitor patient to determine soft tissue vibrating during snoring. As illustrated in FIG. 4, a scope 30 can be placed through the nose 138 into the back of the nasopharynx 140 where it can be used to visualize anatomical structures in the oropharynx 100 and airway passages 102 while a patient is sleeping and snoring. The scope 30 and related equipment 32 and 34 may be used for remotely steering the scope tip 42 and displaying video images acquired from its tip 42 . In one embodiment, the scope 30 may be made of a thin and flexible fiber optic cable such as those used in pediatric endoscopes. The scope 30 may be inserted through the patient's nose 138 so that it lies in the back of the upper airway passage 102 where it can be steered so as to visualize the various soft tissues of the oropharynx 100 that are likely to be responsible for snoring. When the patient is asleep and snoring occurs, the clinician can use the scope 30 to visualize the location of the vibrating tissue that gives rise to the snoring sounds. This information may provide guidance in selecting the sites to be implanted with a microstimulator 10 . [0092] In one embodiment, the efficacy of an anatomical site selected may be tested prior to the implantation of a microstimulator 10 . For example, stimulation pulses may be applied to a potential anatomical site through conventional electrodes that can be incorporated into or passed temporarily through an insertion tool 36 . Ultrasonic imaging of an insertion tool 36 , microstimulator 10 and the oropharynx 100 may be used during the implantation procedure. [0093] In one embodiment, the function of the microstimulator 10 may be tested at the implantation site prior to release from the insertion tool 36 . For example, where the insertion tool 36 includes a sheath 38 , the microstimulator 10 may be advanced to the distal-most end of the sheath and stimulated to produce an electrical stimulation. If the desired response is obtained, the sheath 38 may be retracted holding the microstimulator 10 in position with a trochar 40 . Finally, the trochar 40 may be withdrawn from the implantation site. [0094] In one example, the microstimulator stimulation parameters can be selected by variously activating the implanted microstimulator(s) 10 , for example via a transmission coil 20 and monitoring the stiffness of the overlying tissue or breathing and snoring of a sleeping patient, such as by measuring vibrations in the oropharynx, volume of sounds in the proximity of the oropharynx, or the activity or tension in a muscle in the oropharynx. The activation of a microstimulator 10 and control of the stimulation parameters may be performed by a user interface such as is provided by application-specific software running on a personal computer 28 that may be functionally connected to a controller 24 , as illustrated in FIG. 3. [0095] After implantation of at least one microstimulator 10 , monitoring may continue, such as via a scope 30 , to observe the muscle contraction produced by transmitting command signals for various patterns of electrical stimulation to the microstimulator 10 . This procedure may be conducted before the microstimulator 10 is released from the insertion tool. This procedure may also done while the patient sleeps. [0096] The clinician may use software in a computer 28 to devise various stimulation parameters and to deliver them to controller 24 , which may formats command signals for transmission to the implanted microstimulator 10 , such as via transmission coil 20 and driver 22 . When a stimulation parameter program has been identified that is effective in contracting at least one muscle in the oropharynx 100 to stiffen the proximate tissue or retract soft tissue from the airway passages 102 , it may be loaded into non-volatile memory in controller 24 so that the patient can use the controller 24 to deliver the stimulation program at home while sleeping, as illustrated in FIG. 1, described above. In one embodiment, controller 24 may be turned on and running a stimulation program such that command signals are sent to at least one implanted microstimulator 10 when and only when the patient places their head 120 in the proximity of a transmission coil 20 , thereby entering the magnetic field generated by transmission coil 20 and driver 22 . [0097] In some embodiments, the microstimulator 10 may only receive power and/or command signals if it is sufficiently close to the RF transmission coil 20 . Therefore, it is possible for the treatment to fail if during sleep the patient moves their head away or turns to an orientation for which the coupling between microstimulator 10 and transmission coil 20 is too weak for normal operation. Various technical approaches can be employed to address this problem. [0098] In one embodiment, the transmission coil 20 may be adapted so as to be attached to the patient during sleep, such as in the form of a collar or clip to be attached to the patient's clothing in the proximity of the microstimulator. [0099] In one embodiment, a back-telemetry signal may be generated from each microstimulator 10 to a transmission coil 20 , which then acts as an antenna to detect this back-telemetry signal. Various means for generating such back-telemetry signals are well-known in the field of implantable transponders for use in the identification of animals, such as those described in U.S. Pat. Nos. 5,211,129 and 5,697,076, the content of which are incorporated herein by reference. For example, if and when a microstimulator 10 receives a command signal, it may generate both the requested stimulation pulse and a back-telemetry signal which is then received by transmission coil 20 and processed through its supporting driver 22 and conveyed to controller 24 . If controller 24 determines that an unacceptable number of the stimulation commands that it issues are not received by and acted upon by a microstimulator 10 , then the controller 24 may generate an audible or visible alarm designed to alert the patient to reposition themselves relative to the transmission coil 20 so as to receive the prescribed treatment. [0100] In one embodiment, the system may also include the transmission of an acknowledgement signal from the microstimulator 10 to a controller 24 , where the acknowledgement signal indicates that the microstimulator has received a control signal from a controller. This embodiment may be useful at least in that it may be difficult for a patient to sense whether or not a microstimulator is active because the muscles which are stimulated are small and produce mechanical actions that are not readily felt or visible. [0101] In one embodiment, the invention may allow a clinician to specify the stimulation program. The system may also include transmitting an acknowledgement signal from the microstimulator to a controller, wherein the acknowledgement signal indicates that the microstimulator has received a control signal from a controller. The stimulation program may include alarm conditions and contingencies specified by the clinician. The system may also allow tracking/recording and responding back to an alarm system events as part of the program usage and control. The system may also provide to the patient acknowledgement confirming when the microstimulator 10 is correctly positioned relative to external components of the system and/or the system is working correctly (such as immediate feedback). The system may also notify the patient if failures over certain clinician set criteria occur (e.g., snoring persists in spite of implantation and stimulation of microstimulators according to the set parameters.) Finally, the system may include a mechanism to start and stop alarm conditions that arise during sleep. The mechanism may be selected to be intuitive to the patient and easy to operate so that it can be silenced quickly and easily upon waking from sleep. [0102] Stimulation Parameters. The stimulation patterns are preferably selected to activate the selected microstimulator 10 at the selected time, at the selected intensity for the selected duration of time to cause contraction of at least one muscle in the oropharynx. The stimulation parameters may be selected to cause contraction of a muscle, but also not fatigue the muscle. Ultimately, muscle fatigue leads to a flaccid muscle, loosening of tissue proximate to the muscle and the retreat of the soft tissues into the airway passages 102 of the patient and snoring may resume. The stimulation parameters may be selected so as to cause the desired change in the tone of the airway passages 102 , while minimizing unwanted motion, patient arousal during sleep, cutaneous stimulation, interference with normal movement of the muscle or function of the nerve. [0103] The stimulation parameters may be loaded into a controller 24 which is positioned to control the microstimulator 10 , or may be loaded directly into the microstimulator 10 . [0104] The electrical activation of the microstimulator 10 to contract a muscle in the oropharynx need not be synchronized with either inhalation or exhalation. However, a reduction in the frequency or magnitude of snoring may be obtained while at least some stimulation of the oropharyngeal muscle(s) is present. Continuous stimulation at one site however, may be undesirable because the activated muscle fibers may fatigue quickly, particularly if the hydrostatic pressure in the muscle resulting from the contraction reduces blood flow to the local muscle fibers. Thus, it is preferable alternately to apply stimulation to contract the muscle, then allow a period for the muscle to relax, rather than contracting a muscle continuously. [0105] In one mode of operation, an electrical stimulation pattern may be applied less than continuously to at least one microstimulator to intersperse periods of no stimulation to reduce muscle fatigue. The muscles and soft tissues of the airway passages 102 have inertia and viscoelastic properties that slows their rate of relaxation. Fatigue tends to occur rapidly when muscles contract continuously for more than a few seconds because contraction is accompanied by an increase in hydrostatic pressure that may be sufficient to occlude blood flow in the muscle. Brief interruptions of stimulation may be sufficient to reduce hydrostatic pressure so as to permit circulation of the blood but not so long as to allow the soft tissues to relax into a position where snoring recurs. In one embodiment stimulation parameters may include interruptions in the stimulation pattern in the range of about 0.2-2 s every about 5-20 s. [0106] Plurality of microstimulators. If the soft tissues responsible for the snoring retreat into the airway passages 102 and begin vibrating upon relaxation of the muscle, more than one microstimulator may be implanted within the same muscle (where they will recruit largely non-overlapping populations of motor units) or in different muscles. A plurality of microstimulators may be separately stimulated in an alternating pattern, so that each muscle has a period of rest but at least one is always being stimulated. [0107] Although now having described certain embodiments of a method for treating snoring, it is to be understood that the concepts implicit in these embodiments may be used in other embodiments as well. In short, the protection of this application is limited solely to the claims that now follow.	Many individuals generate excessively loud snoring during their sleep, often to the point where others cannot tolerate sleeping in the same room with them. Most cases of snoring are caused by excessive bulk and flaccidity of soft tissues of the palate and uvula that vibrate as air flows past them. These palate and uvula contain muscles whose contractions can stiffen and displace the soft tissues so that they do not vibrate. The invention provides electrical stimulation that causes the oropharyngeal muscles to contract during sleep using one or more microstimulators injected into or near these muscles or the nerves which innervate them. The invention also provides methods of determining the anatomical structures implicated in snoring and testing such locations for effective placement and stimulation of muscle contraction to decrease the frequency or magnitude of snoring.	0
FIELD OF THE INVENTION [0001] The invention relates to a process for reducing sticky contaminants in stock systems containing waste paper and in coated broke, and their reuse in the manufacture of papers. BACKGROUND OF THE INVENTION [0002] It is prior art to return paper waste from natural fibrous materials for economically expedient reuse. For this purpose, mechanical and chemical processes are often usually used together for dispersion, removing printing ink (de-inking), bleaching, cleaning (washing) and screening. [0003] As a result of the increased input of mixed waste paper as a source of raw material in papermaking, large quantities of solid or water-soluble, sticky constituents are also carried into the paper machine circuits. They constitute a significant cause of so-called “stickies” and “white pitch” which, because of their hydrophobic properties, are often deposited on hot and moving parts and in the wires and felts of paper machines and can therefore lead to paper web breaks. [0004] “stickies” is understood to mean sticky deposits in the form of organic complexes, which are formed from the waste paper by the agglomeration of disruptive materials which interact with one another. All sticky deposits which are introduced exclusively via the raw materials are referred to as “primary stickies”. If, on the other hand, the formation of the sticky contaminants is brought about only after reaction with additives, then these deposits are referred to as “secondary stickies”. The main source for sticky contaminants are adhesives from paper conversion, but also synthetic binders from paper finishing. [0005] “white pitch” is a special case of “sticky” formation, which is associated with the use of polyvinyl acetate and styrene butadiene latices, for example from coated paper broke (Das Papier (1998) 10 A, V 36 -V 41; Wochenblatt für Papierfabrikation (1990) 8, 310-313). [0006] The aforementioned “stickies” and “white pitch” are to be viewed as disruptive materials in papermaking, which as far as possible have to be “neutralized” in terms of their stickiness or separated. [0007] In order to ensure effective treatment of disruptive materials, the size distribution of the disruptive materials to be encountered is critical for the thermal, chemical and/or mechanical processes to be used. [0008] A rough distinction is drawn between macrostickies for particle sizes above 150 μm, which can largely be removed from the stock circulation by means of the aforementioned separating processes, and microstickies made of sticky contaminants between 1 μm and 150 μm [0009] In most cases, microstickies do not cause any problems in papermaking if they do not agglomerate. In addition, they are then below the visibility limit. [0010] In order to prevent re-agglomeration of the microstickies to a large extent, various processes are known for the chemical modification of the stickies remaining in the stock stream and their absorption on carrier materials with a high specific surface and on the fibrous material. [0011] Here, the following procedures have been tried and tested in practice, but lead only to partial success. [0012] 1. Dispersion with the Aim of Changing the Charging of the Stickies by Means of Anionic and Non-ionic Dispersants [0013] By this means, colloidal, charged particles are formed which counteract agglomeration and deposition. The wetting properties of the dispersant are very important in this case, since the “stickies” are generally hydrophobic. [0014] 2. Reducing the Tackiness of the Stickies by [0015] Fixing the highly anionic disruptive materials by means of highly cationic fixing agents (fonning so-called polyelectrolyte complexes; the reaction product is then attracted to the anionic fibre), [0016] Absorption on synthetic fibres, pigments with a high specific surface (e.g. talc, modified clay, mica, smectite, bentonite), often with subsequent flocculation by means of polymers to bind together separable macroflocs, [0017] Covering (masking) with non-ionogenic hydrophilic polymers or anionic zirconium compounds, in particular of zirconium acetate and ammonium zirconium carbonate. [0018] Known highly cationic fixing agents are polyethylene imine (PEI), polydiallyldimethyl-ammonium chloride (PDADMAC), polyvinyl amine (PVAm), polyaluminium chloride (PAC), polyacrylamide (PAAM) and so on. The range of action of fixing agents extends, depending on the type and modification of the chemicals used, from about 1 nm to 50 μm particle size of the microstickies (Das Papier (1998) 10 A, V 36 -V 41). [0019] Solids with a low surface energy exhibit a hydrophobic behaviour and therefore have a high affinity with hydrophobic substances, such as stickies. These absorption agents also include, amongst others, the synthetic fibres polyester, polyamide and polypropylene. [0020] Further adsorption agents used are primarily various types of talc with a specific surface modification and grain size distribution which, because of their hydrophobic and organophilic surface, are capable of depositing on sticky constituents and carrying them out with the paper. Adhesive particles encapsulated in this way show a lower tendency to deposition on hot machine parts. Combating sticky deposits by means of talc has some drawbacks, however. For example, the system is very sensitive to shear. In addition, talc is difficult to retain and often leads to blinding of the felts. Talc can have a detrimental effect on resin sizing and stabilizes foam. [0021] For partial overflocking, highly concentrated flocking agents, such as aluminium sulphate, aluminate, acids and so on, are used. [0022] Known masking agents for stickies are, amongst others, ethoxilated nonylphenols and ethoxilated dodecylphenols having at least 9 mol ethylene oxide, whose use is limited to dosage rates of 10 ppm because of an extreme tendency to foaming (Wochenblatt für Papierfabrikation (1990) 8, 310 -313). [0023] In addition, graft copolymers of polyalkylene oxide and partially saponified vinylacetate (up to 15% saponification) with a weight ratio of 1:0.2 to 1:10, are used as masking agents, if appropriate in combination with other papermaking aids, it being possible for the polyalkylene oxide to be polyethylene, polypropylene or polybutylene oxide (EP 0571144 A1). [0024] Likewise, alkoxylation products, which are obtained by reacting alkylene oxides with C 10-22 carbonic acid derivatives and/or C 10-22 carbonic acids, act as masking agents (DE 195 15 273 A1). [0025] A hydrophilic polymer based on vinyl alcohol, which contains some hydrophobic groups such as acetates, propionates, butyrates or oleates and has molecular weights from 2 000 to 125 000 or more (EP 0220001 B1), is used under the commercial name BETZ DETAC® (trademark of the BETZ company) to combat the stickiness of hydrophobic stickies by means of covering them with a hydrophilic film over a wide pH and temperature range. This partially saponified polyvinyl alcohol (PVAL) is usually metered in the thick stock area, in order to ensure an adequate reaction time of 20-30 min with the stock to be treated, given good and thorough mixing. The necessary dosage rates to combat stickies successfully depend on the type and quantity of the waste paper used. Any influence by other aids is ruled out because of their non-ionic charge (Wochenblatt für Papierfabrikation (1990) 8, 310-313). [0026] An excess of PVAL would have an extremely detrimental effect on the papermaking process and on effluent loading, since it is not needed to cover the sharply varying proportion of stickies, depending on the selected dispersion conditions (shear intensity, pH and temperature range, combination of aids). [0027] The formation of foam and an increase in the disruptive materials carried by the waste water (COD and BOD content) result. An additional difficulty is the poor biodegradability of PVAL. [0028] On the other hand, underdosing with PVAL would lead to inadequate masking of all the sticky constituents. [0029] In relation to the pulping of separated base paper broke, the selective adsorption capability of alkali modified bentonites with respect to various water-soluble polymers, in particular with respect to PVAL, in effluent has been demonstrated (Wochenblatt für Papierfabrikation (1996) 4, 148-152). [0030] Accordingly, 130 mg of dissolved PVAL is bound by 1 g of bentonite (ratio about 1:7.5). Practical investigations on effluent with different disruptive material loadings and types ultimately led to the result that, in practice, for safety reasons, eight to nine times the quantity of bentonite, based on the water-soluble PVAL proportion in the effluent, is used. As a result, at least 90 % of the dissolved PVAL from the effluent could be absorped and carried out with the paper. As a result of the combined use of bentonite and cationic fixing agent, such as PAC and PEI, in the preparation of broke, the content of dissolved hydrocolloids in the effluent could be reduced still further. [0031] This beneficial action of a combined use of alkali modified bentonite and cationic fixing agent for the absorption of PVAL dissolved in the effluent has until now been practised only in the pulping of separated base paper broke surface-sized with PVAL and CMC. [0032] A use of the aforementioned combination in the dispersion of waste paper and coated broke, in which partially saponified polyvinyl alcohol is added as a masking agent for microstickies, appears to be ruled out, since a very wide range of disruptive material loadings and a multiplicity of sticky constituents of varied chemical composition would lead to uncontrolled interactions. SUMMARY OF THE INVENTION [0033] The object of the invention was, therefore, to use the positive properties of partially saponified polyvinyl alcohols as a chemical agent for masking sticky constituents (microstickies) more effectively, from a process engineering point of view, for papermaking which will be less susceptible to disruption and more environmentally friendly with respect to protecting water supplies. [0034] Surprisingly, the expected disruptive interactions could largely be avoided by selecting the correct dosing sequence of the individual components and the correct dosing location, depending on application. [0035] For this purpose, it was necessary first of all for partially saponified PVAL to be introduced in a certain excess at that point in the process of preparing waste paper and coated broke where either macrostickies had already been removed by known separation processes and only microstickies were predominantly still present in the stock system, or even no macrostickies could still be formed. [0036] The point of addition for masking sticky microstickies can therefore be located in the thick stock and also in the thin stock area, depending on the selected preparation and separation technique. DESCRIPTION OF THE PREFERRED EMBODIMENTS [0037] What is claimed is a process for reducing sticky contaminants, in particular those with a finely divided composition (microstickies) in the preparation of stock systems containing waste paper and of coated broke, characterized in that, after mechanical preparation has been carried out and, if necessary, coarse sticky constituents (macrostickies) have been separated, the stock system has added to it at least one water-soluble organic polyol, in particular a water-soluble polyvinyl alcohol or a mixture of various water-soluble organic polyols, in particular a mixture of various water-soluble polyvinyl alcohols, and bentonite and, if appropriate, further chemical additives and fillers. [0038] The organic polyvinyl alcohols used are water-soluble polymers with proportions of vinyl alcohol or a copolymer of vinyl alcohol and vinyl acetate, which contain hydrophobic groups and are hydrolyzed to more than 70% by weight. [0039] The organic polyvinyl alcohols are used after the mechanical preparation in proportions from 0.05 to 2% by weight, in particular from 0.1 to 1.0% by weight, based on fibrous material, in combination with bentonites with a high specific surface, preferably alkali modified bentonites, in proportions from 1 to 10% by weight, based on fibrous material. [0040] The organic polyvinyl alcohols used have a molecular weight from 1 000 to 250 000, preferably 90 000 to 150 000. [0041] The polyol may also be a water-soluble organic copolymer which contains repeating units of vinyl alcohol and of non-ionic hydrophilic monomers, ionic hydrophilic monomers and/or hydrophobic monomers, the water-soluble organic copolymers comprising at least 20 mol% vinyl alcohol. [0042] Examples of hydrophobic monomers are vinyl acetate, propylene oxide, methacrylate, methylethacrylate, octadecylacrylate, n-octadecylacrylamide, styrene, allyl stearate, vinyl stearate, ethene, propene, n-butene, isobutene, pentene, dodecene, octadecene and vinyl ether higher than methyl. [0043] Examples of non-ionic hydrophilic monomers are vinyl pyrrolidone, ethylene oxide and acrylamide. [0044] The copolymer can have random distribution of the monomer units or various degrees of block formations and/or alternations in the polymer. [0045] Block formation means that in the copolymer there are regions which are formed by only one of the monomers, while in the case of alternation, a monomer of one sort is always bound to a monomer of the other sort. [0046] The polyvinyl alcohols may also be modified, for example by cationic groups. [0047] In a preferred process, the prepared stock mixture also has added to it cationic fixing agents in proportions from 0.05 to 1% by weight (commercially available), based on fibrous material. [0048] In a likewise preferred process, further conventional chemical additives (such as, inter alia, dry strengthening agents, wet strengthening agents and sizing agents) and fillers 10 (inter alia, clay, calcium carbonate and talc) are mixed in. [0049] What is also claimed is paper which is produced by means of a secondary fibrous material mixture prepared in accordance with the process of the invention. EXAMPLES [0050] The process according to the invention, comprising a combination of partially saponified polyvinyl alcohol, alkali modified bentonite and cationic fixing agents, is explained by the following exemplary embodiments: [0051] Exemplary Embodiment 1 [0052] By means of a high-speed laboratory stirrer (10 000 rev/min) small cut paper pieces of constant fibrous composition and with an addition of different contact adhesives of about 10% was disintegrated at a consistency of 4% for a period of 5 min until it was free of specks (microstickies below the visibility limit of about 150 μm). [0053] The stock mixture prepared in this way then had added to it, in a different sequence, various hydrophilicization agents, in particular partially saponified polyvinyl alcohols as masking agents, pigments with a high specific surface, in particular bentonites, as adsorption agents, and various cationic fixing agents of different chemical composition. The amount added was 1% by weight (commercially available) in the case of fixing and masking agents and, respectively, 5% by weight (solids) in the case of adsorption agents, based on fibrous material. [0054] Following each addition of one of the abovementioned products, attention is paid to adequate thorough mixing before any possible addition of a further product. Following the addition of partially saponified polyvinyl alcohols, attention is paid to an action time of 30 min in accordance with the recommendation of the chemical suppliers before a further product is added to the stock mixture. [0055] The preparation conditions, such as pH and temperature, can be varied over a wide range. [0056] Then, laboratory sheets are formed in accordance with the ZELLCHEMING standard method and dried, and in addition filtrates from the stock samples are taken in order to determine the chemical oxygen demand (COD). [0057] Since to date no method of determining microstickies below 150 μm in stock systems exists, recourse must be made to COD determination, although this permits only a statement about the trend towards sticky loading (Wochenblatt für Papierfabrikation (1997) 9, 468-477). [0058] Therefore, composite materials from the formed, moist paper sheets are additionally prepared together with aluminium foil by being compressed with one another within 30 seconds in a hot press at 20 bar pressure and 130° C. and later, following cooling and intermediate storage under standard conditions (24 h at 23° C./50% relative humidity), the forces needed to separate the two layers, approximating to the FINAT method, can be determined. The higher the separation force, the higher is the residual stickiness of the microstickies. In addition, the stickiness of any residues adhering to the laboratory stirrer, and their elimination by means of a powerful water jet, are assessed. [0059] The results of some laboratory trials are presented in Tables 1 to 6. The results were deliberately selected at a dispersion temperature of 60° C., since partially saponified polyvinyl alcohols are only effective as a masking agent above 100° F. (38° C.). [0060] If, for example, the additives already mentioned are added as individual components to a fibrous stock mixture with an addition of 10% adhesive of different composition, then in general a decrease in the stickiness of the microstickies is found on the basis of the separation force measurements (Tables 1, 3 and 5). In this case, fixing agents can be just as effective as adsorption or hydrophilicization agents (masking agents). [0061] However, as expected, talc is generally less beneficial in its effect than bentonite as an adsorption agent (Tables 1 and 3). [0062] On the other hand, hydrophilicization agents based on partially saponified polyvinyl alcohols belong in the group of additives which bring about the lowest reduction in the COD value in the filtrate, and to some extent even increase it. In this case, the degree of saponification and further properties of the polyvinyl alcohols used, such as molecular weight, viscosity and so on, appear to play a part (Tables 1 and 5). [0063] This points to the fact that polyvinyl alcohol is no longer deposited on the microstickies but also strays into the effluent in dissolved form. [0064] A remedy is provided only by the combination of partially saponified polyvinyl alcohol and alkali modified bentonite (Table 2, Variant A3+B2). A fixing agent which is additionally used can, if necessary, reduce the COD value still further (Table 2, Variant A3+B2+A1), but in the least favourable case, can also make the separation force and COD values worse again (Table 2, Variant A3+B2+B1). From this it is possible to derive the fact that, depending on the stock and adhesive system used, the optimum fixing agent in this combination of additives has to be found. [0065] Using the combination according to the invention of polyvinyl alcohol/bentonite (Table 2, Variant A3+B2), it is clear that the best results with respect to the reduction of the stickiness of microstickies can be achieved. If, on the other hand, the adsorption agent bentonite (B2) is replaced by talc (A2), then this combination (polyvinyl alcohol A3+talc A2) is less effective by far if the separation force values are used as a basis (Table 2), or even disadvantageous in the case of a different adhesive addition (rubber instead of acrylate adhesive, Table 6). [0066] Combinations of adsorption agents (talc or bentonite) with fixing agents were likewise not very effective with respect to reducing the separation force (Table 4). [0067] Exemplary Embodiment 2 [0068] A broke paper had about 5% (solids) of an acrylate contact adhesive added to it, and this stock mixture was well and thoroughly mixed under practical conditions in a technical centre pulper for a period of about 45 min at a moderate consistency of 6% and a temperature of about 60° C. The pH of the stock mixture was adjusted to about 6. [0069] In the order specified, the following were then added to the stock mixture as additives: [0070] 1. partially saponified polyvinyl alcohol (1%) [0071] 2. alkali modified bentonite (2.5% solids) [0072] 3. cationic fixing agent (0.6%) [0073] in each case a mixing period of 30 min (in the case of polyvinyl alcohol) and, respectively 10 min being maintained before the addition of the next component. [0074] The COD content of originally about 320 mg O 2 /l in the filtrate was reduced to below 150 mg O 2 /l by means of this combination. [0075] Residual stickiness of the microstickies in the formed paper sheet, which could be demonstrated by dyeing with a special blue dye, could no longer be demonstrated by means of separation force measurement (initial value of the sample without additives was more than 5 N). [0076] This therefore confirms the positive results of the combination of partially saponified polyvinyl alcohol/bentonite/cationic fixing agent from the laboratory trial (Exemplary embodiment 1). [0077] This stock mixture, thus treated in accordance with the invention, was used to produce new paper without any disruptive deposits in the paper machine system (machine part, water circulation). TABLE 1 Influence of additives on the reduction of the stickiness of stickies (microstickies) ACRYLATE ADHESIVE I DISPERSION: pH = 7 at 60° C. Addition as individual component hydrophilicization agent Cationic fixing agent adsorption agent (masking agent) no additive A1 B1 A2 B2 A3 B3 Separation force, N 6.17 3.66 3.98 3.53 3.91 4.49 3.34 COD, mg O 2 /1 185 69 100 116 123 162 134 Sticky residues many Removability poor [0078] [0078] TABLE 2 Influence of the combination of additives on the reduction of the stickiness of stickies (microstickies) ACRYLATE ADHESIVE I Dispersion: pH = 7 at 60° C. Addition as combination of additives hydrophilicization hydrophilicization agent + Adsorption agent + agent + adsorption agent + no fixing agent adsorption agent fixing agent additive A2 + B1 B2 + B1 A3 + A2 A3 + B2 A3 + B2 + A1 A3 + B2 + B1 Separation force, N 6.17 6.78 6.92 5.28 3.01 3.30 4.37 COD,mg O 2 /I 185 268 243 121 116 39 248 [0079] [0079] TABLE 3 Influence of additives on the reduction of the stickiness of stickies (microstickies) ACRYLATE ADHESIVE II Dispersion: pH <3 at 60° C. Addition as individual component No Cationic fixing agent adsorption agent additive C1 A2 B2 Separation force, N 4.28 3.29 3.71 3.80 COD, mg O 2 /l 112 110 88 165 Sticky residues few Removability good [0080] [0080] TABLE 4 Influence of the combination of additives on the reduction of the stickiness of stickies (microstickies) ACRYLATE ADHESIVE II Dispersion: pH <3 at 60° C. Addition as combination of additives adsorption agent adsorption agent no A2 + fixing B2 + fixing additive agent C1 agent C1 Separation force, N 4.29 4.36 4.28 COD, mg O 2 /l 112 82 46 [0081] [0081] TABLE 5 Influence of additives on the reduction of the stickiness of stickies (microstickies) RUBBER ADHESIVE Dispersion: pH = 7 at 60° C. Addition as individual component No adsorption hydrophilicization agent additive agent A2 (masking agent) B3 Separation force, N 4.91 4.85 4.20 COD, mg O 2 /l 171 156 212 Sticky residues many Removability poor [0082] [0082] TABLE 6 Influence of the combination of additives on the reduction of the stickiness of stickies (microstickies) RUBBER ADHESIVE Dispersion: pH = 7 at 60° C. Addition as combination of no hydrophilicization agent (masking agent) additive A3 + adsorption agent A2 Separation force, N 4.91 5.85 COD, mg O 2 /l 171 214	The invention relates to a process for reducing sticky contaminants in stock systems containing waste paper and in coated broke, and their reuse in the manufacture of papers. In this process, both polyvinyl alcohols and bentonite are added.	3
The U.S. government has rights in this invention by virtue of the partial funding of work leading to this invention through the National Institutes of Health. This application is a divisional of U.S. Ser. No. 08/148,990 filed on Nov. 8, 1993, by Dennis C. Liotta and Bharat Ramkrishna Lagu entitled "Diastereoselective Synthesis of Hydroxyethylene Dipeptide Isosteres," now U.S. Pat. No. 5,587,514. This invention is in the area of organic synthesis, and is in particular a diastereoselective synthesis of hydroxyethylene dipeptide isosteres. BACKGROUND OF THE INVENTION Hydroxyethylene dipeptide isosteres ("peptide mimics" or "peptidomimetics," illustrated below) are compounds in which a peptide bond is replaced with a non-hydrolyzable hydroxyethyl isostere that mimics a peptide enzymic transition state. Compounds incorporating hdyroxyethyl isosteres have recently generated considerable interest due to their ability to act as HIV-protease and renin inhibitors. Szelke, M., Jones, D. M., Hallet, A., Leckie, B. J., Proc. Am. Pept. Symp. 8th, 1983, 579; Meek, T. D., J. Enz. Inhib., 1992, 6, 65. The amino alcohol functionality in active peptidomimetics has (4S,5S) stereochemistry, as indicated below. Peptidomimetics also possess a substituent at the C2 position with the indicated absolute configuration. The "S" or "R" designation of the C2-substituent is a function of substituent priority. ##STR1## Large quantities of hydroxyethylene dipeptide HIV-protease inhibitors and renin inhibitors are currently in demand for laboratory and clinical testing as well as for potential commercialization. Many of the prior synthetic approaches to these isosteres employ the lactone 1 as a key intermediate which is derivatized via diastereoselective alkylation of the enolate followed by ring opening. Several groups have synthesized 1 from α-amino aldehydes in a variety of ways, including by: (a) addition of a homoenolate equivalent (DeCamp, A. E., Kawaguchi, A. T., Volante, R. P., Shinkai, I., Tetrahedron Lett., 1991, 32, 1867); (b) addition of lithium ethyl propiolate (Fray, A. H., Kaye, R. L., Kleinman, E. F., J. Org. Chem., 1986, 51, 4828); (c) addition of allylic organometallic reagents (Vara Prasad, J. N. V., Rich, D. H., Tetrahedron Lett., 1990, 31, 1803); or (d) by conversion of α-amino aldehydes into α-amino epoxides (Evans, B. E., Rittle, K. E., Homnick, C. F., Springer, J. P., Hirshfield, J., Veber, D. F., J. Org. Chem., 1985, 50, 4615). The synthesis of 1 from a carbohydrate precursor such as D-mannose (Ghosh, A. K., McKee, S. P., Thompson, W. T., T. Org. Chem., 1991, 56, 6500), or via a γ-ketoester derived from N-Cbz-L-phenylalanine (Hoffman, R. V., Kim, H., Tetrahedron Lett., 1992, 33, 3579), N-benzyl-N-BOC-phenylalanine (Dondoni, A., et al., Tetrahedron Lett., 1992, 33, 7259), or N-phthalimido-phenylalanine (Sakurai, M., et al., Tetrahedron Lett., 1993, 34, 5939), have also been reported. U.S. Patents which disclose methods for the synthesis of hydroxyethylene dipeptide isosteres include U.S. Pat. No. 5,192,668 entitled "Synthesis of Protease Inhibitor," issued Mar. 9, 1993; U.S. Pat. No. 5,188,950 entitled "Method of Preparing HIV Protease Inhibitors," issued Feb. 23, 1993; U.S. Pat. No. 5,187,074 entitled "Method of Hydroxylation with ATCC 55086, " issued Feb. 16, 1993; U.S. Pat. No. 5,175,298 entitled "Dipeptide Hydroxy Ethylene Isostere Synthesis and Intermediate Therefor," issued Dec. 29, 1992; and U.S. Pat. No. 5,169,952 entitled "Stereoselective Production of Hydroxyamide Compounds from Chiral Alpha-Amino Epoxides," issued Dec. 8, 1992. While these syntheses are successful in producing the target compound, the syntheses proceed with variable stereocontrol, and can exhibit one or more other drawbacks such as a relatively long synthetic sequence, the use of expensive starting materials, or the use of a starting material such as an α-amino aldehyde which is prone to racemization or which produces variable diastereoselectivity depending on the nature of the `R'` group. For example, the Hoffman process (wherein the hydroxyethylene dipeptide isostere is prepared by the alkylation of a t-butyl β-ketoester with an α-bromocarboxylic acid), after hydrolysis, decarboxylation and reduction results in a mixture of 4R and 4S isomers in an approximate ratio of 1.8:1, which must be separated. The DeCamp, et al. process uses an α-amino aldehyde as a starting material that is easily racemized under a variety of experimental conditions. The amino aldehyde is reacted with a titanium homoenolate prepared from ethyl 3-bromopropionate to provide a mixture of (4S/4R) diastereomers that must be separated. The reaction of N,N-dibenzyl-phenylalanine with a dichloroisopropoxytitanium homoenolate using the DeCamp protocol results in a ratio of 4R to 4S diastereomers of greater than 20 to. Another stereoselective synthesis of hydroxyethylene dipeptide isosteres was recently reported by Diederich and Ryckman. Diederich, "Stereoselective Synthesis of a Hydroxyethylene Dipeptide Isostere," Tetrahedron Lett., 1993, 34, 6169-6172. The Diederich synthesis is based on the conversion of a dibenzyl-L-amino acid to the corresponding N'-methyl-O-methylcarboxamide, which is reacted with a Grignard reagent derived from 2-(2-bromoethyl)-1,3-dioxolane or 2-(2-bromoethyl)-1,3-dioxane to produce a (2S)-2-dibenzylamino-5-[1,3]dioxolan-2-yl-1-phenyl-pentan-3-one or (2S)-2-dibenzylamino-5-[1,3]dioxan-2-yl-phenyl-pentan-3-one, respectively. Reduction of the carbonyl moieties provides the desired amino alcohol function with high 4S-stereoselectivity. The C2-substituent is added by conversion of (2S)-2-dibenzylamino-5-[1,3]dioxolan-2-yl-1-phenyl-pentan-3-one or (2s)-2-dibenzylamino-5-[1,3]dioxan-2-yl-phenyl-pentan-3-one to its corresponding lactone, followed by alkylation of the lactone and ring opening. Diederich's synthesis suffers from the disadvantages that not all of the reagents are commercially available (the Grignard reagents have to be generated), the reagents can be relatively expensive, and the oxidation step requires chromium, which presents waste disposal problems. None of the known syntheses for hydroxyethylene dipeptide isosteres provides the optimal combination of the use of stable and inexpensive starting materials, high stereoselectivity, high yield, and minimal number of process steps. In light of the strong need for large quantities of hydroxyethylene dipeptide isosteres for the research and development of HIV-protease inhibitors and renin inhibitors, it would be of benefit to provide an economical method for their synthesis. Therefore, it is an object of the present invention to provide a method for the preparation of hydroxyethylene dipeptide isosteres that results in a product with (4S,5S) stereochemistry. It is another object of the present invention to provide a method for the preparation of hydroxyethylene dipeptide isosteres that places a substituent group in the C2-position with the proper configuration. It is another object of the present invention to provide a method for the preparation of hydroxyethylene dipeptide isosteres that is simple and efficient. It is another object of the present invention to provide a method for the preparation of hydroxyethylene dipeptide isosteres that can be carried out on a manufacturing scale. SUMMARY OF THE INVENTION A process is provided for the diastereoselective synthesis of hydroxyethylene dipeptide isosteres from α-N,N-di(protected)amino(alkyl or substituted alkyl) methyl ketones that can be efficiently carried out on an industrial scale. This process is a significant advance over prior known processes for the preparation of this family of compounds, in that the process involves only a small number of steps, the starting material, α-N,N-di(protected)amino(alkyl or substituted alkyl) methyl ketone is less prone to racemization than the prior used aldehydes, and the overall sequence provides excellent diastereoselectivity and chemical efficiency. The starting α-N,N-di(protected)amino(alkyl or substituted alkyl)methyl ketones can be synthesized according to known procedures. As shown in FIGS. 1 and 2, the ketones are converted into their corresponding γ-keto esters or amides in high yield by treatment with an enolate forming reagent, followed by addition of an α-(leaving group)-acetate or α-(leaving group)-acetamide. The γ-keto ester or amide is then reduced to provide a hydroxyethylene dipeptide precursor with the necessary (4S,5S) stereochemistry. The important C2-substituent of the hydroxyethylene dipeptide is added by cyclization of the C2-unsubstituted hydroxyethylene dipeptide to its corresponding lactone which is alkylated via its enolate. The lactone is then opened to either a carboxylic acid or amide in good yield. The ester can be converted to the amide according to known procedures. In an alternative embodiment, as shown in FIG. 3, the enolate of an acetic acid ester, amide or the equivalent, is reacted with an α-N,N-di(protected)amino(alkyl or substituted alkyl) methyl(leaving group)ketone to produce the corresponding γ-keto ester, which is treated as described above to produce the peptidomimetic. In yet another embodiment, illustrated in FIGS. 1 and 3, the C2-substituent is positioned on the starting acetic acid ester or amide. Using this method, a wide variety of hydroxyethylene dipeptide isosteres can be prepared for a variety of uses, including as HIV-1 protease inhibitors and renin inhibitors. BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a schematic illustration of a method for preparing a hydroxyethylene dipeptide isostere from α-N,N-di(protected)amino(alkyl or substituted alkyl) methyl ketone and an α-(leaving group)-acetate according to the present invention. FIG. 2 is a schematic illustration of one method for preparing a peptidomimetic with an alanine or phenylalanine amino-terminus using the following reagents and conditions: a) NaHMDS, THF, -78° C., b) BrCH 2 CO 2 t-Bu, -78° C., c) NaBH 4 , methanol, 0° C., d) toluene, acetic acid, reflux, e) H 2 /Pd black, absolute ethanol, BOC 2 O, f) phenylCH 2 Br, -78° C., 30 minutes. FIG. 3 is a schematic illustration of a method for preparing a hydroxyethylene dipeptide isostere from the enolate of an acetic acid ester and an α-N,N-di(protected)amino(alkyl or substituted alkyl) methyl(leaving group) ketone according to the present invention. DETAILED DESCRIPTION OF THE INVENTION The term alkyl, as used herein, unless otherwise specified, refers to a saturated straight, branched, or cyclic, primary, secondary, or tertiary hydrocarbon of C 1 to C 10 , and specifically includes methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, cyclopentyl, isopentyl, neopentyl, hexyl, isohexyl, cyclohexyl, cyclohexylmethyl, 3-methylpentyl, 2,2-dimethylbutyl, and 2,3-dimethylbutyl. The alkyl group can be optionally substituted with one or more moieties selected from the group consisting of hydroxyl, amino, alkylamino, arylamino, alkoxy, aryloxy, nitro, cyano, sulfonic acid, sulfate, phosphonic acid, phosphate, or phosphonate, either unprotected, or protected as necessary, as known to those skilled in the art, for example, as taught in Greene, et al., "Protective Groups in Organic Synthesis," John Wiley and Sons, Second Edition, 1991. The term alkylamino or arylamino refers to an amino group that has one or two alkyl or aryl substituents, respectively. The term "protected" as used herein and unless otherwise defined refers to a group that is added to an oxygen or nitrogen atom to prevent its further reaction during the course of derivatization of other moieties in the molecule in which the oxygen or nitrogen is located. A wide variety of oxygen and nitrogen protecting groups are known to those skilled in the art of organic synthesis. The term amino acid as used herein, refers to a natural or synthetic amino acid, and includes, but is not limited to alanyl, valinyl, leucinyl, isoleucinyl, prolinyl, phenylalaninyl, tryptophanyl, methioninyl, glycinyl, serinyl, threoninyl, cysteinyl, tyrosinyl, asparaginyl, glutaminyl, aspartoyl, glutaoyl, lysinyl, argininyl, and histidinyl. The term aryl, as used herein, and unless otherwise specified, refers to phenyl, biphenyl, or naphthyl, and preferably phenyl. The aryl group can be optionally substituted with one or more moieties selected from the group consisting of hydroxyl, amino, alkylamino, arylamino, alkoxy, aryloxy, nitro, cyano, sulfonic acid, sulfate, phosphonic acid, phosphate, or phosphonate, either unprotected, or protected as necessary, as known to those skilled in the art, for example, as taught in Greene, et al., "Protective Groups in Organic Synthesis," John Wiley and Sons, Second Edition, 1991. The term halo, as used herein, includes chloro, bromo, iodo, and fluoro. The term heteroaryl or heteroaromatic, as used herein, refers to an aromatic moiety that includes at least one sulfur, oxygen, or nitrogen in the aromatic ring. Nonlimiting examples are furyl, pyridyl, pyrimidyl, thienyl, isothiazolyl, imidazolyl, tetrazolyl, pyrazinyl, benzofuranyl, benzothiophenyl, quinolyl, isoquinolyl, benzothienyl, isobenzofuryl, pyrazolyl, indolyl, isoindolyl, benzimidazolyl, purinyl, carbozolyl, oxazolyl, thiazolyl, isothiazolyl, 1,2,4-thiadiazolyl, isooxazolyl, pyrrolyl, quinazolinyl, pyridazinyl, pyrazinyl, cinnolinyl, phthalazinyl, quinoxalinyl, xanthinyl, hypoxanthinyl, pteridinyl, 5-azacytidinyl, 5-azauracilyl, triazolopyridinyl, imidazolopyridinyl, pyrrolopyrimidinyl, pyrazolopyrimidinyl, adenine, N 6 -alkylpurines, N 6 -acylpurines (wherein acyl is C(O)(alkyl, aryl, alkaryl, or aralkyl), N 6 -benzylpurine, N 6 -halopurine, N 6 -vinylpurine, N 6 -acetylenic purine, N 6 -acyl purine, N 6 -hydroxyalkyl purine, N 6 -thioalkyl purine, thymine, cytosine, 6-azapyrimidine, 2-mercaptopyrimidine, uracil, N 5 -alkylpyrimidines, N 5 -benzylpyrimidines, N 5 -halopyrimidines, N 5 -vinylpyrimidine, N 5 -acetylenic pyrimidine, N 5 -acyl pyrimidine, N 5 -hydroxyalkyl purine, and N 6 -thioalkyl purine, and isoxazolyl. Functional oxygen and nitrogen groups on the heterocyclic base can be protected as necessary or desired during the reaction sequence. Suitable protecting groups are well known to those skilled in the art, and include trimethylsilyl, dimethylhexylsilyl, t-butyldimethylsilyl, and t-butyldiphenylsilyl, trityl, alkyl groups, acyl groups such as acetyl and propionyl, methylsulfonyl, and p-toluylsulfonyl. The term alkylheterocyclic or alkylheteroaromatic refers to a moiety in which the alkyl group is covalently attached to the heteroaromatic, is preferably C 1 to C 4 alkyl-heteroaromatic, and more preferably CH 2 -heteroaromatic. The term alkaryl, as used herein, refers to an alkyl group with an aryl substituent, for example, benzyl, α-methyl benzyl, and phenethyl. The term aralkyl, as used herein, refers to an aryl group with an alkyl substituent. The term alkoxy, as used herein, and unless otherwise specified, refers to a moiety of the structure --O-alkyl. The term BOC, as used herein, refers to t-butyloxycarboxy. The term leaving group, as used herein, refers to a moiety that can be displaced by an enolate or other nucleophile in an S N 2 reaction. The term peptide, as used herein, refers to two or more amino acids connected via amide linkages. A process is presented for the preparation of hydroxyethylene dipeptide isosteres in which a peptide bond is replaced with a non-hydrolyzable hydroxyethylene isostere, that mimics a peptide enzymic transition state. The process, or standard modifications or extensions thereof, can be used to prepare a wide variety of HIV-1 protease inhibitors and renin inhibitors, including those described in Meek, "Inhibitors of HIV-1 Protease, Enzyme Inhibition, 1992, Vol 6., 65-98, incorporated herein by reference. I. Starting Materials and Intermediates of the Process In one embodiment, the process, as illustrated in FIG. 1, includes reacting an enolate of an α-N,N-(diprotected)amino ketone of the formula R 1 CHN(R 2 ) 2 C(O)CH 3 with an α-substituted carboxylic acid ester of the formula CH 2 XC(O)OR 3 or R 4 CHXC(O)OR 3 , to form a 5-substituted-(5S)-5-(N,N-diprotected amino)-4-oxo-pentanoic acid ester of the formula R 1 CHN(R 2 ) 2 C(O)CH 2 CH 2 C(O)OR 3 or R 1 CHN(R 2 ) 2 C(O)CH 2 CHR 4 C(O)OR 3 , respectively. The latter compound, R 1 CHN(R 2 ) 2 C(O)CH 2 CHR 4 C(O)OR 3 , on deprotection and reduction of the ketone, provides a selected peptidomimetic with the appropriate (S)-stereochemistry at the 4 and 5 positions, and the R 4 substituent in the C2-position. The former compound, R 1 CHN(R 2 ) 2 C(O)CH 2 CH 2 C(O)OR 3 , can be modified to include a desired substituent (referred to as R 5 ) in the C2-position by reduction of the C4 ketone followed by cyclization to the lactone followed by alkylation via the corresponding enolate, and ring opening. Preferred C2-substituents are benzyl, isobutyl, methyl, isopropyl, cyclohexyl, t-butyl, aryl, and t-alkyl, for example, t-butyl. When racemic R 4 CHXC(O)OR 3 is used as a starting material, a diastereomeric product is obtained that can be separated if desired according to known methods. If enantiomerically pure R 4 CHXC(O)OR 3 is used as a starting material, a single enantiomer is produced. According to the invention, R 1 can be the residue of an amino acid (and preferably a naturally occurring amino acid), i.e., the moiety connected to --CHNH 2 CO 2 H, including but not limited to methyl, ethyl, benzyl, hydrogen, isopropyl, HOCH 2 --, --CHOHCH 3 , --CH 2 SH, 2-methylpropyl, 1-methylpropyl, --CH 2 CH 2 SCH 3 , --CH 2 (indole), --CH 2 (p-hydroxyphenyl), (CH 2 ) 4 NH 2 , --CH 2 (imidazole), --CH 2 CH 2 C(O)NH 2 , --CH 2 C(O)NH 2 , --CH 2 CO 2 H, --CH 2 CH 2 CO 2 H, (wherein functional groups are protected as necessary during the reaction), or other alkyl, aryl, alkaryl, heteroaromatic, alkyl(heteroaromatic), arylamino, or aralkyl group. The R 1 moiety should not render the hydrogen on the adjacent carbon acidic and should not contain a carbonyl moiety that would interfere with the reaction. R 1 is preferably methyl or benzyl. R 2 is a bulky group that can control the facial selectivity of attack of the enolate on the CH 2 XC(O)OR 3 or R 4 CHXC(O)OR 3 . R 2 , which can vary independently on the amine, is preferably a benzyl or substituted benzyl group, wherein the substituent is alkoxy, preferably p-methoxy. In a preferred embodiment, an R 2 group is selected that is removed easily from the product of reaction. p-Methoxybenzyl groups can be removed from the amine when desired by oxidation with ceric ammonium nitrate. Tertiary butyl groups can be used to direct the facial selectivity of attack of the enolate, however, they are typically difficult to remove from the product. In a preferred embodiment, the R 2 groups on the amine are alike, however, two different R 2 groups can be used to protect an amine. For example, the amine can be protected with a combination of benzyl, BOC, benzyloxycarbonyl, or p-methoxybenzyl, however, in a preferred embodiment, at least one of the groups is a benzyl group. An appropriate combination of protecting groups can be selected such that one of the groups can be removed selectively as desired. R 3 can be any moiety that does not adversely affect the S N 2 reaction protocol, and in particular, which does not encourage attack by the enolate of the α-N,N-(diprotected)amino ketone on the carbonyl of CH 2 XC(O)OR 3 or R 4 CHXC(O)OR 3 . Specifically, R 3 can be an alkyl, aryl, heteroaromatic, alkylheteroaromatic, aralkyl, alkaryl, and is preferably a bulky group such as t-butyl which hinders addition to the carbonyl by the enolate. It has been noted that when ethyl is the ester moiety using the reaction protocol set out in FIG. 1 using an ethyl-α-bromo-acetate substrate, a complex mixture of products results. R 4 is any group that does not unacceptably slow the rate of, or interfere with the S N 2 reaction, for example, a primary, secondary, or tertiary alkyl or alkaryl group, and is most preferably methyl, ethyl, propyl, isopropyl, butyl, isobutyl, cyclohexylmethyl, benzyl or phenethyl. R 4 can also be an aryl or aralkyl group, for example, phenyl or alkylphenyl, or a heterocyclic or alkylheterocyclic moiety. In one embodiment, R 4 is t-butyl. X is any moiety that can be displaced in an S N 2 reaction, including but not limited to bromo, chloro, iodo, triflate, tosylate, diazonium salts, mesylates, and brosylates. R 5 is any group, which, when attached to X, can be attacked by an enolate ion, resulting in the substitution of the enolate moiety for X, and is typically a primary or secondary alkyl or alkaryl moiety, and is preferably methyl, benzyl, isobutyl, isopropyl, or cyclohexylmethyl. It is important to note that either R 4 or R 5 becomes the C2-substituent in the hydroxyethylene dipeptide isostere product. According the process described herein, while R 5 is typically limited to primary or secondary alkyl or alkaryl groups because it must be susceptible to attack by an enolate ion in an S N 2 reaction, R 4 can be a wide variety of moieties, including R 5 moieties as well as aryl, heteroaryl and tertiary alkyl groups. In an alternative embodiment, as shown in FIG. 3, the enolate of an acetic acid ester formed from CH 3 C(O)OR 3 or R 4 CH 2 C(O)OR 3 is reacted with R 1 CHN(R 2 ) 2 C(O)CH 2 X to form R 1 CHN(R 2 ) 2 C(O)CH 2 CH 2 C(O)OR 3 or R 1 CHN(R 2 ) 2 C(O)CH 2 CHR 4 C(O)OR 3 , respectively, which is treated as described above to produce the desired peptidomimetic. In another alternative embodiment, CH 2 XC(O)N(R 6 ) 2 , R 4 CHXC(O)N(R 6 ) 2 , CH 3 C(O)N(R 6 ) 2 or R 4 CH 2 C(O)N(R 6 ) 2 , wherein R 6 is hydrogen, alkyl, alkaryl, aryl, aralkyl, heterocyclic, or alkylheterocyclic, and wherein R 6 can vary within the molecule, is used in the reaction sequence in place of the acetic acid ester. For example, a (4S,5S)-hydroxyethylene dipeptide isostere can be prepared by reacting an α-N,N-di(protected)amino methyl(leaving group) ketone with a compound selected from the group consisting of the enolate of acetic acid ester and and the enolate of acetamide to form the corresponding γ-keto ester, which is further derivatized as described in detail herein. Some of the compound intermediates used in the disclosed process are novel compounds (wherein R 1 , R 2 , R 3 , and R 4 are as defined above unless indicated otherwise), including but not limited to: (i) R 1 CHN(R 2 ) 2 C(O)CH 2 CHR 4 C(O)OR 3 , wherein R 4 is as defined above; ##STR2## wherein R 4 is aryl, aralkyl, heteroaryl or t-alkyl; ##STR3## wherein R 2 and R 6 are independently (and can vary within the molecule) as defined above or hydrogen; and (v) R 1 CHN(H 2 ) 2 C(O)CH 2 CHR 4 C(O)OH, wherein R 4 is as defined above. Compounds (i) and (v) can be used as intermediates to prepare compounds that have a second moiety on the carbon alpha to the carbonyl via appropriate enolate reactions using Compounds (ii). Compounds (iii) can be used to prepare Compounds (iv), which can be used in vitro as research tools to study the structure-activity relationship, including bulk tolerance relationships, of HIV-protease inhibitors and renin inhibitors, or which can be used in vivo as HIV-protease inhibitors and renin inhibitors which are administered as disclosed in U.S. Pat. No. 5,244,910 entitled "Renin Inhibitors," issued Sep. 14, 1993; U.S. Pat. No. 4,894,437 entitled "Novel Renin Inhibiting Polypeptide Analogs Containing S-Aryl-D- or L- or DL-cysteinyl, 3-(Arylthio)Lactic Acid or 3-(Arylthio)Alkyl Moieties," issued Jan. 16, 1990; U.S. Pat. No. 4,882,420 entitled "Dihalo-Statine Substituted Renin Inhibitors," issued Nov. 21, 1989; U.S. Pat. No. 4,880,781 entitled "Renin Inhibitory Peptides Containing an N-Alkyl-Histidine Moiety," issued Nov. 14, 1989; U.S. Pat. No. 4,864,017 entitled "Novel Renin Inhibiting Peptides Having a Dihydroxyethylene Isostere Transition State Insert," issued Sep. 5, 1989; and U.S. Pat. No. 4,705,846 entitled "Novel Renin Inhibiting Peptides having a Gamma Lactam Pseudo Dipeptide Insert," issued Nov. 10, 1987. II. Description of Process Steps The process steps for preparing hydroxyethylene dipeptide isosteres are described in more detail below. Given this disclosure, one of ordinary skill in the art will be able to routinely modify the synthetic steps as desired or necessary to achieve specific results. Modifications of the process steps or equivalent steps are considered to fall within the scope of this invention. All of the reactions described below can be carried out in standard organic solvents that do not react or otherwise interfere with the process. Given the description of the process steps below, one of ordinary skill in the art of organic synthesis will be able to select an appropriate solvent for each step. Preferred solvents are typically tetrahydrofuran and acetonitrile. Other solvents that can be considered for selected reactions include a dialkyl formamide, such as dimethyl formamide; dialkyl sulfoxide such as dimethyl sulfoxide; chlorinated solvents such as d-chloromethane, chloroform, carbon tetrachloride, trichloroethane, and tetrachloroethane; alcohols such as methanol, ethanol, and propanol; benzene, alkylated benzenes such as toluene, o, m, and p-xylene; alkoxybenzenes such as o, m, and p-cresol; ethers such as methyl t-butyl ether, tetrahydrofuran, and diethyl ether; glymes such as diglyme and triglyme; straight chain or branched alkyl solvents such as hexane, hexanes, heptane, pentane, and petroleum ether (ligroin); alkyl nitriles other than acetonitrile; nitroalkyl solvents such as nitromethane; and perfluoroalkyl solvents. Step 1 Preparation of α-N,N-Di(protected)amino(alkyl or substituted alkyl) Methyl Ketone α-N,N-Di(protected)amino(alkyl or substituted alkyl) methyl ketones can be prepared as described in Lagu, et al, "Highly Diastereoselective Aldol Reactions of Chiral Methyl Ketones," J. Org. Chem., 1993, 58, 4191-4193, or Reetz, et al., Tetrahedron: Asymmetry, 1992, 1, 375. Generally, a selected amino acid, for example, a naturally occurring amino acid, is first converted to its N,N-diprotected derivative using known procedures. The protecting group typically also adds to the carboxylic acid moiety, forming an ester that can be removed by selective hydrolysis or selective catalytic transfer hydrogenolysis (Bajwa, Tetrahedron Lett., 1992, 33, 2299). The amino-protected carboxylic acid can be converted to the desired ketone using published or otherwise known procedures, for example, the Mukaiyama or Jorgenson-Gilman protocols (Mukaiyama, et al., Chem. Lett. 1974, 663; Jorgenson, J. Org. React. 1970, 18, 1) Reetz, et al., synthesized α-N,N-dibenzyl amino ketones from the corresponding α-(L)-amino acids. They reported that the nitrogen protecting group on the α-(L)-amino acid has an influence on the diastereoselectivity of nucleophilic addition. Reetz also reported that the keto group can be reduced with excellent diastereoselectively to yield a vicinal amino alcohol with S,S stereochemistry at the stereogenic centers. Reetz, M. T., Drews, M. W., Lennick, K., Schmitz, A., Holdgrun, X, Tetrahedron: Asymmetry, 1990, 1, 375; Reetz, M. T., Drews, M. W., Matthews, B. R., Lennick, J., J. Chem. Soc., Chem. Commun., 1989, 1474. Lagu, et al, has reported that aldol reactions of lithium enolates of α-(N,N-dibenzylamino)alkyl methyl ketones proceed diastereoselectively with a variety of aldehydes. Neither Reetz nor Lagu extended their study to the use of α-(N,N-diprotected)alkyl methyl ketones in S N 2 displacement reactions. Step 2 Generation of the Enolate of α-N,N-Di(protected)amino(alkyl or substituted alkyl) Methyl Ketone (FIG. 1) or the Enolate of Acetic Acid Ester (FIG. 3) and Preparation of γ-keto ester In the second step according to this process, α-N,N-di(protected)amino(alkyl or substituted alkyl) methyl ketone (FIG. 1) or a selected acetic acid ester or other carboxylic acid ester (FIG. 3) or the corresponding amide is converted to its corresponding enolate, which is reacted with an α-(leaving group) acetic acid ester or α-N,N-di(protected)amino(alkyl or substituted alkyl) methyl(leaving group) ketone, respectively, in an S N 2 process to provide a desired γ-keto ester. It should be noted that α-N,N-di(protected)amino(alkyl or substituted alkyl) methyl ketone can form either a thermodynamic (most highly substituted) enolate or a kinetic (least substituted) enolate. In this process, it is necessary to generate the kinetic enolate of the methyl ketone. In contrast, the acetic acid ester can only form one type of enolate because the carbonyl is flanked by an --OR 3 moiety on one side. Lithium or sodium salts of hindered nitrogen bases are often used to form enolates. A variety of groups can be used to hinder the amine in the hindered nitrogen base, as known to those skilled in the art. Preferred reagents to generate enolates include amide bases such as LDA, sodium hexamethyldisilazide (NaHMDS), and potassium hexamethyldisilazide (KHMDS), optionally in combination with HMPA, TMEDA, or other reagents, as known to those skilled in the art. Sodium hexamethyldisilazide is a preferred reagent for the formation of the enolate of α-N,N-di(protected)amino(alkyl or substituted alkyl) methyl ketone in this process. The sodium enolate produced by sodium hexamethyldisilazide is more ionic, and less regiostable, than its lithium counterpart. The use of lithium enolates also results in slightly lower yields in certain cases. Other enolate forming reagents that can be used in this process include hydride sources such as KH or NaH alone, or trialkyl silyl hydrides with Co 2 (CO) 8 , titanium enolate forming reagents, for example, TiCl 4 and boron enolate forming reagents, for example from Bu 2 BOTf. In one embodiment, a enolate is generated in a derivative of the acetic acid ester or amide in which the moiety attached to the carbonyl is a chiral auxiliary, as illustrated below. A wide variety of auxiliaries are known to those skilled in the art, as discussed, for example, in Heathcock, C. H., Modern Synthetic Methods; Scheffold, R., Ed.; Verlag Helvetica Chimica Acta: CH-400 Basel, 1992; pages 1-102; d Evans, D. A., Asymmetric Synthesis, Vol. 3. Academic Press, New York, 1984, Chapter 1. Chiral auxiliaries can simultaneously control both the enolate geometry and the facial selectivity of its reactions with electrophiles. This provides a means of controlling the stereochemistry at the C2 carbon. Many chiral auxiliaries are imides. Other examples of commonly used auxiliaries are 4-methyl-5-phenyl-2-oxazolidinone; 4-benzyl-2-oxazolidinone; 4-isopropyl-2-oxazalidinone, and 2,10-camphorsultam. ##STR4## The enolate is typically generated in situ in an inert solvent such as tetrahydrofuran under an inert atmosphere such as argon or nitrogen. Other suitable solvents include other ethereal solvents such as diethyl ether and hydrocarbon solvents such as pentane and toluene. The α-(leaving group) acetic acid ester or α-N,N-di(protected)-amino(alkyl or substituted alkyl) methyl(leaving group) ketone is added slowly to the reaction solution. This reaction is typically carried out at a temperature ranging between -78 and 0 degrees centigrade, for a time ranging from approximately 30 minutes to two hours, or until completion of reaction. Step 3 Reduction of γ-Keto Ester to a Hydroxyethylene Dipeptide Isostere In Step 3, the γ-keto ester prepared in Step 2 is reduced to the corresponding hydroxyethylene dipeptide isostere using known procedures. A preferred reducing agent is sodium borohydride. Other suitable reducing agents include diisobutylaluminum hydride (DIBAL-H), lithium borohydride (LiBH 4 ), and sodium bis(2-methoxyethoxy)-aluminum hydride (Red-Al). The reduction is typically carried out at low temperature, for example, 0 degrees centigrade, for one hour, or until the reduction is complete. The reaction can be conducted in anhydrous methanol or other suitable solvent. Step 4 Cyclization of Hydroxyethylene Dipeptide Isostere Active hydroxyethylene dipeptide isosteres have a C2-substituent. Alkyl and alkaryl groups can be added to the C2-position of a C2-unsubstituted hydroxyethylene dipeptide isostere by cyclization of the isostere to the corresponding lactone, followed by alkylation of the lactone through its enolate and ring opening. Cyclization of the γ-hydroxy carboxylic acid ester can be accomplished under acidic conditions as known to those skilled in the art, including by treatment with methanesulfonic acid and glacial acetic acid in dry toluene. Other acids that can be used in the cyclization process include, but are not limited to, sulfuric acid and resinous sulfonic acids, such as Dowex-50 and Nafion, alkylsulfonic acids other than methanesulfonic acid, arylsulfonic acids, hydrobromic acid, hydrochloric acid, phosphoric acid, alkylphosphoric acid, nitric acid, nitrous acid, carboxylic acids and diacids, for example as acetic acid, formic acid and oxalic acid. The cyclization is typically conducted under anhydrous conditions at 80-111 degrees Centigrade for six to twelve hours, or until the cyclization is complete. The process embodiment wherein R 4 CHXC(O)OR 3 or R 4 CH 2 C(O)OR 3 is used as a starting material to form R 1 CHN(R 2 ) 2 C(O)CH 2 CHR 4 C(O)OR 3 obviates the need to carry out Steps 4, 5 and 6, wherein the C2-substituent (R 5 ) is added to the hydroxypeptide isostere via an enolate reaction. Step 5 Alkylation of Lactone The lactone prepared as described in Step 4 or as otherwise known in the art is alkylated through its enolate according to known procedures. The enolate can be generated in an inert solvent under an inert atmosphere as described in Step 2. A preferred base for the generation of the enolate is sodium hexamethyldisilazide. The enolate is typically generated under anhydrous conditions at a temperature ranging from approximately -78 to -60 degrees Centigrade. After generation of the enolate, a selected XR 5 is added to the reaction solution. The reaction is allowed to proceed to completion, generally in thirty minutes to one hour. Step 6 Ring Opening of Lactone The alkylated lactone prepared as described in Step 5 or as otherwise known in the art can then be converted into the required isostere by a ring opening reaction using the Weinreb amidation protocol. Basha, A., Lipton, M., Weinreb, S. M., Tetrahedron Lett., 1977, 4171. Alternatively, the lactone can be opened to the corresponding carboxylic acid, that can be converted to the desired isostere using known procedures. Examples 1-7 provide a detailed description for one process for the preparation of the peptidomimetic (5S)-5-(N,N-dibenzylamino)-2-ethyl-(4S)-4-hydroxy-hexanamide according to the present invention, illustrated in FIG. 2. This example is merely illustrative, and not intended to limit the scope of the invention. EXAMPLE 1 Preparation of N,N-dibenzylalanine ##STR5## Benzaldehyde (7.0 mmol, 7.0 mL) was added to a suspension of L-alanine (20.0 mmol, 1.78 g) in acetonitrile (30.0 mL) and water (20.0 mL) at room temperature. The resulting turbid solution was stirred at room temperature for 30 minutes. Sodium cyanoborohydride (2.5 eq., 50.0 mmol, 3.2 g) was then added in one portion, and the resultant yellowish solution was stirred for 60 minutes (exothermic reaction). A few drops of glacial acetic acid were added in order to maintain a pH of approximately 6. After 30 minutes, a white precipitate appeared. The suspension was filtered through a sintered glass funnel using 100 mL of diethyl ether. The organic solvents were removed in vacuo. The aqueous solution was extracted with Et 2 O (2×75 mL), and the organic layer was washed with brine. The organic layer was then dried over anhydrous sodium sulfate, filtered, and the solvent was removed in vacuo to yield 13.0 g of yellow liquid. Benzaldehyde and benzyl alcohol were removed by distillation under reduced pressure. The yellow solid was further purified by column chromatography on silica gel with 1:1 hexanes/ethyl acetate as the eluting system (Rf=0.2) to yield 2.8 g (52%) of N,N-dibenzyl alanine. 1 H NMR (300.15 MHz) δ 1.39 (d, J=7.2 Hz, 3H), 3.54 (q, J=8.7 Hz, 1H), 3.70 (ABq, δ A=3.54, δ 6=3.85, J=16.2 Hz, 4 H), 7.26-3.38 (m, 11 H); HRMS for C 17 H 20 NO 2 : 270.149. (calc'd 270.1489). EXAMPLE 2 Preparation of α-(N,N-dibenzylamino)ethyl methyl ketone ##STR6## Triethylamine (8.85 mmol, 1.24 mL) was added under an argon atmosphere to a stirred solution of N,N-dibenzylalanine (8.85 mmol, 2.38 g) in tetrahydrofuran (THF) (53.0 mL) at -30° C. (dry ice/CCl 4 bath). Trimethyl acetyl chloride (8.85 mmol, 1.42 mL) was then added dropwise via syringe and the turbid solution was allowed to stir at -30° C. for 30 minutes before dropwise addition of a solution of methylmagnesium chloride in THF (3.0M, 1.07 eq., 9.5 mmol, 3.23 mL) over 10 minutes. The solution was stirred for 45 minutes and then quenched with saturated solution of NH 4 Cl (5.0 mL). The solution was extracted with Et 2 O, the organic extracts washed with brine, dried over MgSO 4 , and filtered. The solvent was evaporated in vacuo and the residue was subjected to flash column chromatography on silica gel with 8:1 hexanes/ethyl acetate to isolate a pure product in 65% yield. Colorless oil; R=0.43 (7:1 hexanes/ethyl acetate) 1 H NMR (300.15 MHz) δ 1.19 (d, J=5.4 Hz, 3 H), 2.25 (5, 3 H), 3.39 (q, J=6.9 Hz, 1 H), 2.57 (AB quartet, δ A =3. 33, δ B =3. JAS=13.8 Hz, 4 H), 7.19-7.43 (m, 10 H); 13 C NMR (75.5 MHz 7.1, 27.7, 54.6, 62.9, 27.2, 128.5, 128.8, 139.3, 210.8; IR (Neat) 1710 cm -1 ; MS (low resolution) m/e 268 M+H 22%), 224 (MeCHNBn 2 , 100%); HRMS for C 18 H 22 NO: 268-1709 (calc'd 268-1676); Anal: calc'd for C 18 H 21 NO: C 80.68, H 7.92, N 5.24; Found: C 80.79, H 7.95, N 5.17. EXAMPLE 3 Preparation of (5)-5-(N,N-dibenzylamino)-4-oxo-hexanoic acid-tert-butyl ester ##STR7## Tetrahydrofuran (5.5 mL) was introduced via syringe to a three-necked 25 mL round bottom flask purged with argon. The flask was cooled to -78° C. with a dry ice-acetone bath, and a solution of sodium hexamethyldisilazide in THF (3.3 eq., 1.0 M, 3.3 mL) was added. Compound 2a (α-(N,N-dibenzylamino)ethyl methyl ketone, 1.0 eq., 3.0 mmol) in THF (3.5 mL) was then added dropwise via syringe. The resultant yellow solution was allowed to stir at -78° C. for 1 hour, after which t-butyl α-bromoacetate (3.1 mmol, 0.48 mL) was added neat to the enolate solution. The reaction was quenched at -78° C. with a saturated solution of NH 4 Cl after 30 minutes. The solution was extracted with Et 2 O (2×20 mL), and the organic layer was separated and dried over anhydrous sodium sulfate. The solvent was removed in vacuo and the resultant yellow oil was then purified by flash column chromatography on silica gel with 8:1 hexanes/ethyl acetate as the eluting system to obtain the product in 94% yield. Colorless oil, 1 H NMR (300-15 MHz) δ 1.22 (d, J=G-C 1 3 H), 1.44 (s, 9 H), 2.40-2.55 (m, 2 H), 2.70-2.81 (m, 1 H), 3.04-3.18 (m, 1 H), 3-45 (q, J=6-9 Hz, 1 H), 3.62 (AB quo δ A =3.49, δ B =3.75, JAB=13.5 Hz, 4 H), 7.25-7.51 (m 10 H); 13 C NMR (75.5 MHz) 7.1, 28.0, 29.4, 34.9, 54.5, 62.2, 80.2, 127.1, 128.4, 128.7, 139.2, 171.9, 210.9; IR (Neat) 1720 cm -1 (br); MS (low res.) 382.4 (M+1, 21%), 326.3 (M- t Bu, 7%), 224.3 (MeCHNBn 2 , 100%); HRMS for C 24 H 32 NO 3 : 282.2373 (calc'd 382.2374); Anal: calc'd for C 24 H 31 NO 3 : C 75.55, H 8-19, N 3.67, O 12.58; Found: C 75-54, H 8.21, N 3.63. EXAMPLE 4 Reduction of (5S)-5-(N,N-dibenzylamino)-4-oxo-hexanoic acid-tert-butyl ester (3a) to (5s)-5-(N,N-dibenzylamino)-44-hydroxy-hexanoic acid-tert-butyl ester (4a) ##STR8## Sodium borohydride (2.0 eq., 3.3 mmol, 0.12 g) was added in one portion with stirring to a solution of (5S)-5-(N,N-dibenzylamino)-4-oxo-hexanoic acid-tert-butyl ester (1.65 mmol, 0.63 g) in anhydrous methanol (20.0 mL) at 0° C. (ice-water bath). The solution was stirred for two hours and then quenched carefully with water (5.0 mL). Methanol was removed in vacuo and the residue was extracted with Et 2 O, washed with brine, and dried over anhydrous Na 2 SO 4 . The solvent was removed and the colorless viscous oil obtained (crude wt.=0.65 g) was used in the reaction described in Example 5 without further purification. 1 H NMR (300.15) δ 1.02 (d, J=6.9 Hz, 3 H), 1.29 (s, 9 H), 2.01-2.58 (m, 4 H), 3.54 (AB quartet, δ A =3.29, δ B =3.80, JAB=13.2 Hz, 4 H), 3.41-3.49 (m, 1 H), 4.45 (br, S, 1 H), 7.22-7.35 (m, 10 H); MS (low res.) 384 (m+1, 18%), 328 (M- t Bu, 11%), 224 (MeCHNBn 2 , 100%); HRMS for C 24 H 34 NO 3 : 384.2538 (calc'd 384.2530). EXAMPLE 5 Cyclization of (5S)-5-(N,N-dibenzylamino)-4S-hydroxy-hexanoic acid-tert-butyl ester (4a) to (5S)-5[(1S)-1-(N,N-dibenzylamino)-ethyl]-dihydrofuran-2(3H)-one (5a) ##STR9## Glacial acetic acid (0.4 mL) and one drop of methanesulfonic acid were added to a solution of (5S)-5-(N,N-dibenzylamino)-4-hydroxy-hexanoic acid-tert-butyl ester (0.6 g, 1.57 mmol) in dry toluene (15.0 mL) in a 50 mL round bottom flask fitted with a reflux condenser. The reaction mixture was heated at reflux for 12 hours and then cooled to ambient temperature. The pH of the solution was adjusted to 7 by slow addition of a saturated solution of NaHCO 3 . The organic layer was separated, and the aqueous layer was extracted with Et 2 O (10 mL). The combined organic extracts were dried over MgSO 4 , filtered, and the solvent was removed in vacuo. The residue thus obtained was purified by flash column chromatography on silica gel with 4:1 hexanes/ethyl acetate to obtain 0.41 g (85% yield) of pure (5S)-5[(1S)-1-(N,N-dibenzylamino)-ethyl]-dihydrofuran-2(3H)-one (5a). White solid, mp. 61-62° C., 1 H NMR (300.15) δ 1-11 (d, J=6.6 Hz, 3 H), 1.83-2.15 (m, 2 H), 2.44-2.50 (m, 2 2.86 (pentet, J=6.9 Hz, 1 H), 3.71 (ABq, δ A =3.87, δ B =3.56, JAB=13.8 Hz, 4 H), 4.49 (pentet, J=7.2 Hz, 1 H), 7.10-7.41 (m, 10 H); 13 C NMR (75.8 MHz) 10.9, 25.6, 28.7, 54.3, 55.8, 83.1, 126.8, 128.2, 128.7, 139.9, 177.1; MS (10W res.) 310 (M+1, 20%), 224 (MeCHNBn 2 , 40%), 91 (NBn 2 , 100%); HRMS for C 20 H 24 NO 2 : 310.1807 (calc'd 310.1801); Anal calc'd for C 20 H 23 NO 2 : C 77.64, H 7.49, N 4.53; Found: 77.54, H 7.55, N 4.49. EXAMPLE 6 Alkylation of (5B)-5[(1S)-1-(N,N-dibenzylamino)-ethyl]-dihydrofuran-2(3H)-one to (3S)-3-benzyl-(5S)-5-[(1S)-1-(N,N-dibenzylamino)-ethyl]-dihydrofuran-2(3H)-one (6a) ##STR10## To a stirred solution of sodium hexamethyldisilazide (0.27 mmol, 0.27 mL) in 1.0 mL THF at -78° C., a solution of lactone 5a (0.25 mmol, 0.08 g) in THF (0.5 mL) was added via a syringe under argon atmosphere. The solution was stirred at -78° C. for 1 hour and then treated with benzyl bromide (0.27 mmol, 0.3 mL). The reaction mixture was quenched after 30 minutes with saturated solution of NH 4 Cl. The organic layer was separated and the aqueous layer was extracted with Et 2 O (10 mL). The combined organic extracts were dried over MgSO 4 , filtered and the solvent was removed in vacuo. The residue was further purified by column chromatography under standard conditions to give the alkylated lactone (3S)-3-benzyl-(5S)-5-[(1S)-1-(N,N-dibenzylamino)-ethyl]-dihydrofuran-2(3H)-one (6a) in 81% yield (0.8 g). White solid, 1 H NMR (300.15) δ 1.05 (d, J=6.9 Hz, 3 H), 1.81-2.01 (m, 2 H) 2.74-3.17 (m, 4 H), 3.66 (AGq, δ A =3.50, δ B =3.82, JAB=13.8 Hz, 4 H), 4.25 (q, J=6.6 Hz, 1 H), 7.16-7.38 (m, 15 H); 13 C NMR 11.1, 30.4, 36.6, 41.2, 54.3, 55.6, 81.1, 126.7, 128.2, 128.6=128.9, 138.2, 139.9, 178.7. EXAMPLE 7 Ring Opening Amidation of (3S)-3-benzyl-(5S)-5-[(1S)-1-(N,N-dibenzylamino)-ethyl]-dihydrofuran-2(3H)-one (6a). The amidation can be carried out as described in Basha, A., Lipton, M., Weinreb, S. M., Tetrahedron Lett., 1977, 4171 Examples 8 and 9 provide a detailed description for the preparation of (5S)-5-(N,N-dibenzylamino)-2-ethyl-4-oxo-hexano-(N,N-diethyl)-amide. EXAMPLE 8 Preparation of 2-bromo-(N,N-diethyl)-butyramide ##STR11## The synthesis of the 2-bromo-(N,N-diethyl)-butyramide can be carried out as described by Compagnone, R. S., and Rapoport, H. J. Org. Chem. 1986, 51, 1713. Briefly, to a solution of (±)-2-bromobutyric acid (10.0 mmol, 1.67 g) in THF (20.0 mL) at -10° C. under argon atmosphere was added triethylamine (10.7 mmol, 1.49 mL) followed by isobutyl chloroformate (10.7 mmol, 1.39 mL) dropwise. Diethylamine (12.5 mmol, 1.29 mL) was added to this suspension at -10° C. and the reaction mixture was stirred for 40 minutes. The reaction was quenched by addition of 5.0 mL of a 5% solution of citric acid. The crude product was extracted with Et 2 O, washed with brine, dried over MgSO 4 and solvent evaporated in vacuo to provide 2.4 g of residue which was purified by column chromatography over silica gel with 4:1 hexanes-ethyl acetate as the solvent system (Rf=0.25). The product, 2-bromo-(N,N-diethyl)-butyramide, was obtained in 66% yield (1.46 g) as a colorless liquid. Analytical data: 1 H NMR (300.15 MHz) δ 0.90 (t, J=7.5 Hz, 3H), 1.05 (t, J=7.2 Hz, 3H), 1.16 (t, J=7.2 Hz, 3H), 1.85-2.21 (m, 2H), 3.08-3.52 (m, 4H), 4.20 (t, J=7.2 Hz, 1H); 13 C NMR (75.5 MHz) 12.1, 12.3, 14.7, 28.3, 40.8, 42.2, 45.5, 167.8; IR (neat) 1661 cm -1 (amide C═O str.) EXAMPLE 9 Preparation of (N,N-diethyl)-(58)-5-(N,N-dibenzylamino)-2-ethyl-4-oxo-hexanamide ##STR12## To a solution of NaHMDS (0.52 mmol, 0.53 mL) in 1.0 mL THF at -78° C. was added a solution of α-(N,N-dibenzylamino)ethyl methyl ketone (0.5 mmol, 0.13 g) in 0.5 mL THF under argon atmosphere. After stirring the yellow colored solution for one hour, a solution of 2-bromo-(N,N-diethyl)-butyramide (0.51 mmol, 0.11 g) in 0.5 mL THF was added dropwise. The solution was stirred at -78° C. for 30 minutes and then at ambient temperature for another two hours before quenching with 2.0 mL of saturated solution of NH 4 Cl. After a work-up as described in Example 8, the residue was purified by column chromatography over silica gel with 4:1 hexanes-ethyl acetate as the solvent system (Rf=0.21) to give 0.03 g of α-(N,N-dibenzylamino)ethyl methyl ketone, the starting ketone, and the product as a mixture of diastereomers (0.082 g, 55% yield based on recovered starting material) as a colorless oil. Analytical data: 1 H NMR (very complex spectrum due to diastereomers, diastereotopic protons and rotamers due to rotation around the N--C═O bond); 13 C NMR (one isolated diastereomer) 7.1, 11.7, 12.9, 14.4, 25.9, 37.6, 40.2, 41.9, 42.5, 54.6, 62.1, 127.1, 128.4, 128.6, 139.2 (C═O and N--C═O were not observed possibly due to the low concentration of the compound); IR (neat) 1720 (s, C═O str. for ketone), 1640 (s, C═O str. for amide) cm -1 . Mass spectrum (low resolution) 409 (M+1, 30%), 224 (M--MeCHNBn 2 , 100%). HRMS for C 26 H 37 N 2 O 2 : 409.284 (calc'd 409.2846) Examples 10 and 11 provide a detailed description for the preparation of (5S)-5-(N,N-dibenzylamino)-2-ethyl-4-oxo-hexanoic acid-tert-butyl ester from tert-butyl-2-bromobutyrate and α-(N,N-dibenzylamino)ethyl methyl ketone. This compound is reduced to the corresponding amino alcohol as described in detail above. EXAMPLE 10 Preparation of tert-butyl-2-bromobutyrate ##STR13## tert-Butyl-2-bromobutyrate was synthesized according to the procedure described in Compagnone, R. S., and Rapoport, H. J. Org. Chem. 1986, 51, 1713. EXAMPLE 11 Preparation of (5S)-5-(N,N-dibenzylamino)-2-ethyl-4-oxo-hexanoic acid-tert-butyl ester ##STR14## A solution of α-(N,N-dibenzylamino)ethyl methyl ketone (0.5 mmol, 0.13 g) in 0.5 mL THF was added to a solution of NaHMDS (0.53 mmol, 0.53 mL) in 1.0 mL.THF at -78° C. under argon atmosphere. After stirring the yellow colored solution for one hour, a solution of tert-butyl-2-bromobutyrate (0.51 mmol, 0.11 g) in 0.5 mL THF was added dropwise. The solution was stirred at -78° C. for 30 minutes, and then at ambient temperature for another 2 hours, before quenching with 2.0 mL of saturated solution of NH 4 Cl. After a work-up as described in Example 7, the residue was purified by column chromatography over silica gel with 4:1 hexanes-ethyl acetate as the solvent system (Rf=0.53) to give the product as a mixture of diastereomers (0.047 g, 23% yield) as a colorless oil. Analytical data: 1 H NMR (300.15 MHz) δ 0.83 (t, J=7.5 Hz, 3H), 1.22-1.72 (m, 8H) 1.39 (s, 9H), 3.62-3.86 (m, 5H), 7.23-7.33 (m, 10H); Mass spectrum (low resolution) 410 (M+1, 30%), 224 (M--MeCHNBn 2 , 100%). HRMS for C 26 H 35 O 3 NLi: 416.2773 (calc'd 416-2768). Examples 12 and 13 provide a detailed description for the preparation of methyl-(5S)-5-(N,N-dibenzylamino)-4-oxo-hexanoate from 1-bromo-(3S)-3-N,N-dibenzylamino-butan-2-one. EXAMPLE 12 Preparation of 1-bromo-(3S)-3-N,N-dibenzylamino-butan-2-one ##STR15## A solution of LDA was generated by addition of n-butyllithium (1.05 mmol, 2.5 M) to freshly distilled diisopropylamine (1.2 mmol, 0.16 mL) in 2.0 mL THF at -78° C. under argon atmosphere. To this solution was added a solution of α-S-(N,N-dibenzylamino)ethyl methyl ketone (1.0 mmol, 0.13 g) in 1.0 mL THF. The resulting solution was stirred at -78° C. for one hour and then a solution of bromine (1.05 mmol, 0.06 mL) in 0.5 mL CH 2 Cl 2 was introduced dropwise. The reaction mixture was stirred at -78° C. for 10 minutes and then quenched with saturated solution of NaHCO 3 . The organic layer was extracted with pentane (2×15.0 mL), washed with brine, dried over MgSO 4 , and filtered. The solvent was removed in vacuo to obtain a yellow-orange colored oil which solidified on standing. The crude 1 H NMR showed presence of starting material (approximately 5%), but the reaction product was used in the reaction described in Example 13 without further purification. Analytical data: 1 H NMR (300.15 MHz) δ 1.21 (d, J=6.6 Hz, 3H), 3.60 (AB q , δ A =3.43, δ B =3.69, J=13.5 Hz, 4H), 3.68 (q, J=6.6 Hz, 1H), 4.17 (AB q , δ A =4.14, δ B =4.19, J=13.5 Hz, 2H), 7.23-7.37 (m, 10H). EXAMPLE 13 Preparation of methyl-(5S)-5-(N,N-dibenzylamino)-4-oxo-hexanoate ##STR16## Methyl acetate (1.0 mmol, 0.08 mL) was added dropwise to a solution of LDA (1.05 mmol) in 2.0 mL THF at -78° C., and the resulting solution was stirred for 45 minutes. Hexamethyl phosphoric triamide (1.0 mmol, 0.18 mL) was then added, and after 15 minutes a solution of α-(N,N-dibenzylamino)ethyl bromomethyl ketone (crude from the previous reaction, assumed to be 1.0 mmol) in 2.0 mL was added via syringe. The resulting solution was stirred at -78° C. for 45 minutes and then quenched with saturated solution of NaHCO 3 . After a work-up as described in Example 8, 0.39 g of crude product was obtained. The product was further purified by column chromatography on silica gel with 8:1 hexanes-ethyl acetate as the solvent system (Rf=0.33) to yield 0.21 g (62%) of methyl-(5S)-5-(N,N-dibenzylamino)-4-oxo-hexanoate as a colorless viscous oil. Analytical data: 1 H NMR (300.15 MHz) δ 0.95 (d, J=6.6 Hz, 3H), 2.62-2.30 (m, 4H), 3.36 (q, J=6.2 Hz, 1H), 3.60 (AB q , δ A =3.41, δ B =3.82, J=13.5 Hz, 4H), 3.49 (s, 3H), 7.23-7.37 (m, 10H); 13 C NMR 5.1, 38.9, 48.8, 51.4, 54.4, 57.5, 126.9, 128.2, 128.8, 129.2, 139.4, 170.4, 208.2. This invention has been described with reference to its preferred embodiments. Variations and modifications of the invention will be obvious to those skilled in the art from the foregoing detailed description of the invention. It is intended that all of these variations and modifications be included within the scope of the appended claims.	A process for the synthesis of hydroxyethylene dipeptide isosteres from α-N,N-di(protected)amino(alkyl or substituted alkyl) methyl ketones that can be efficiently carried out on an industrial scale. The process proceeds with excellent diastereoselectivity and chemical efficiency, and can be used to prepare a wide variety of hydroxyethylene dipeptide isosteres for a variety of uses, including as HIV-1 protease inhibitors and renin inhibitors.	2
BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to an exhaust gas purifying catalyst for a lean burn gasoline engine and a diesel engine. [0003] 2. Description of Related Art [0004] It has been known to install a NOx absorbent in an exhaust passage of a lean burn gasoline engine or a diesel engine, the NOx absorbent absorbs NOx in the exhaust gas while an air-fuel mixture has an air-to-fuel ratio on a lean side (O 2 concentration: 5% or higher) and releases the NOx for deoxidization and purification when the oxygen concentration of the exhaust gas is lowered. Typically this type of NOx absorbent has the property of easily absorbing SOx (sulfur compounds: sulfuric acid ions and sulfurous acid ions are included) rather than NOx in the exhaust gas. In consequence, the NOx absorbent that has been poisoned by SOx (which is hereafter referred to SOx-poisoning) encounters a significant reduction in NOx adsorption performance. With respect to sulfur compounds poisoning of the NOx absorbent, Japanese Unexamined Patent Publication No. 8-192051 describes an exhaust gas purifying catalyst that comprises a carrier comprising a composite oxide of Ti and Zr, and a catalytic noble metal and a NOX absorbent which are carried by the composite oxide. This exhaust gas purifying catalyst employs Pt as the catalytic noble metal and at least one selected from a group including alkaline earth metals, alkali metals and rare earth elements as the NOx absorbent. In the exhaust gas purifying catalyst, an Ti—Zr composite oxide easily absorbs SOx, since the NOx absorbent causes a reduction in the probability of contacting to SOx, it is thought that the NOx absorbent is prevented from SOx-poisoning. The Ti—Zr composite oxide has a high acidity, so that it is thought that it is advantageous to improving NOx conversion efficiency of the exhaust gas purifying catalyst. [0005] As a result of a study by the inventor of this applivation, it was revealed that though the Ti—Zr composite oxide absorbs NOx and is, however, hard to absorb SOx, it somewhat weakened its NOx absorption property as well as its SOx absorption property and, in consequence, the NOx absorbent caused not only a reduction in the probability of contacting to SOx but a significantly great reduction in the probability of contacting to NOx, it is thought that the NOx absorbent is prevented from SOx poisoning. That is, even when NOx in the exhaust gas approached the NOx absorbent, the Ti—Zr composite oxide by which NOx absorbent kept the NOx off the NOx absorbent, the NOx was hardly absorbed by the NOx absorbent. SUMMARY OF THE INVENTION [0006] It is therefore an object of the invention to provide an exhaust gas purifying catalyst which comprises not a catalytic layer with a NOx absorbent and a high acid material mixed therein but an under catalytic layer disposed on a substrate and containing a NOx absorbent and an outer high acid oxide layer. [0007] It is another object of the invention to provide an exhaust gas purifying catalyst comprising an under catalytic layer disposed on a substrate and containing a NOx absorbent and a high acid outer oxide layer in which SOx is prevented from reaching the NOx absorbent in the under catalytic layer by the high acid outer oxide layer and NOx is absorbed by the NOx absorbent without blocking by the high acid oxide layer when NOx reaches the under catalytic layer so as to cause SOx escape easily from the under catalytic layer. [0008] According to an aspect of the present invention, the exhaust gas purifying catalyst a catalytic layer disposed on a substrate and containing a NOx absorbent which absorbs NOx in exhaust gas under existence of oxygen, releases the absorbed NOx when an oxygen concentration of exhaust gas lowers and is restrained from absorbing NOx by sulfur compounds in exhaust gas, and an oxide layer disposed over the under catalytic layer and containing a Ce—Zr composite oxide. [0009] The Ce—Zr composite oxide is one of oxides which have an ionic electric field strength of approximately 0.7 e·Å −2 (where e=1.6021892×10 −11 (C·m −2 )). Sulfur oxides (SOx) in exhaust gas are, on one hand, easily absorbed by compounds having high basicity and, on the other hand, hardly absorbed by oxides having high acidity. Therefore, sulfur oxides in exhaust gas are diffused only a little in quantity in the under catalytic layer due to blocking by the Ce—Zr composite oxide contained oxide layer, so as to prevent poisoning the NOx absorbent in the under catalytic layer. In consequence, the sulfur concentration becomes lower in the under catalytic layer than in the outer oxide layer. While NOx in exhaust gas diffuse in and penetrate through the outer oxide layer and are absorbed by the NOx absorbent in the under catalytic layer, the Ce—Zr composite oxide in the oxide layer is considered to somewhat block diffusion and penetration of NOx and, however, does not prevent the penetrated NOx from being absorbed by the NOx absorbent. Further, while the NOx absorbent in the under catalytic layer is somewhat poisoned by sulfur oxides penetrating the outer oxide layer, since sulfur oxides which are released from the NOx absorbent when the oxygen concentration around the NOx absorbent lowers are capable of penetrating through and escaping from the outer oxide layer, the sulfur oxides are less accumulated in the under catalytic layer. [0010] According to another aspect of the invention, the exhaust gas purifying catalyst comprises an under catalytic layer, disposed on a substrate, which has a NOx reducing catalyst for deoxidizing and reducing NOx in exhaust gas, a NOx absorbent for absorbing NOx in exhaust gas under existence of oxygen, releasing the absorbed NOx when the oxygen concentration of exhaust gas lowers, and restrained from absorbing NOx by sulfur compounds in exhaust gas, and a promotor or auxiliary catalyst for absorbing oxygen in exhaust gas and releasing the oxygen when the oxygen concentration in exhaust gas lowers, and an outer oxide layer, disposed over the under catalytic layer, which contains a Ce—Zr composite oxide higher in acidity than the auxiliary catalyst. [0011] The acidity difference such that the auxiliary catalyst in the under catalytic layer has lower in acidity than the Ce—Zr composite oxide in the outer oxide layer provides a tendency to distribute sulfur more densely in the outer oxide layer than in the under catalytic layer, so as to more effectively prevent sulfur poisoning of the NOx absorbent. While the NOx absorbent somewhat lowers its NOx absorbing performance if the auxiliary catalyst in the under catalytic layer attains acidity as high as the outer oxide layer, the auxiliary catalyst having low acidity acts profitably on the NOx absorbing performance of the NOx absorbent. [0012] The auxiliary catalyst preferably comprises one of ceria, CE—Zr composite oxides and composite oxides of Ce, Ti and other metals. [0013] The exhaust gas purifying catalyst may further comprise an in-between layer disposed between the under catalytic layer and the outer oxide layer for activating NOx. The in-between layer separates the under catalytic layer and the outer oxide layer from each other to prevent the outer oxide layer from blocking NOx absorption by the NOx absorbent in the under catalytic layer. Further, the in-between layer activates NOx, so as to profitably act on the NOx absorbing performance of the NOx absorbent. [0014] As the auxiliary catalyst, while it is advantageous to employ ceria in the viewpoint of oxygen absorption performance, nevertheless, a Ce—Zr composite oxide, which has high heat-resistance, is preferably employable in the light of that the exhaust gas purifying catalyst is exposed to exhaust gas at significantly high temperatures. [0015] A noble metal may be contained as a catalytic metal in the NOx reducing catalyst. Noble metals have catalytic activity to NOx deoxidization and reduction from a relatively low temperature, the exhaust gas purifying catalyst profitably acts on NOx purification. [0016] The NOx absorbent preferably comprise at least one selected from a group including alkaline earth metals, alkali metals and rare earth elements for the reason that these metals and elements have high basicity and are, in consequence, advantageous to NOx absorption. Ba may be most preferably employable. Further, the NOx absorbent may be preferable to be lower in acidity than the Ce—Zr composite oxide because NOx is apt to be adsorbed by high acid materials. [0017] The exhaust gas purifying catalyst comprising an under catalytic layer containing a NOx absorbent and an outer oxide layer containing a Ce—Zr composite oxide in accordance with an preferred embodiment prevents the NOx absorbent in the under catalytic layer from sulfur poisoning without a significant loss of NOx absorption performance. [0018] The exhaust gas purifying catalyst comprising an under catalytic layer containing a NOx reduction catalyst, a NOx absorbent and a oxygen absorption promotor or auxiliary catalyst and an outer oxide layer containing a Ce—Zr composite oxide higher in acidity than the oxygen absorption auxiliary catalyst in accordance with an preferred embodiment causes the state in which the sulfur concentration in exhaust easily becomes lower in the under catalytic layer than in the outer oxide layer, which is advantageous to prevention of sulfur poisoning of the NOx adsorbent and improvement of NOx absorption performance. [0019] The incorporation of an in-between layer for activating NOx prevents the oxide layer from blocking NOx absorption of the NOx absorbent and beneficially acts on NOx absorption of the NOx absorbent. BRIEF DESCRIPTION OF THE DRAWINGS [0020] The foregoing and other objects and features of the present invention will be clearly understood from the following detailed description with respect to the preferred embodiment thereof when reading in conjunction with the accompanying drawings, in which: [0021] [0021]FIG. 1 is a schematic cross-sectional view of an exhaust gas purifying catalyst of the invention; [0022] [0022]FIG. 2 is a graphical diagram showing the relationship between Zr molar fraction of a Ce—Zr composite oxide and ionic electric field strength; and [0023] [0023]FIG. 3 is a graphical diagram showing NOx conversion efficiency of an example exhaust gas purifying catalyst of the invention and a comparative exhaust gas purifying catalyst. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0024] Referring to the drawings in detail and, in particular, to FIG. 1, there is shown a layer structure of an exhaust gas purifying catalyst 100 for a vehicle of the type which alters an air-fuel mixture between a lean side on which an excess air ratio λ is greater than one (1) and a rich side on which the excess air ratio λ is equal to or smaller than one (1) in accordance with engine operating conditions. On the lean side, the air-to-fuel ratio is between 22 and 100 and the oxygen concentration of the exhaust gas is higher than 5%. The exhaust gas purifying catalyst 100 comprises three catalytic layers, namely an under catalytic layer 2 , an in-between catalytic layer 3 and an outer catalytic layer, i.e. oxide layer, 4 supported on a substrate 1 . The substrate 1 is of a monolith type of cordierite honeycomb bed which has too cells per inch and six mil thickness wall between each adjacent cells. The under catalytic layer 2 contains a NOx absorbent and, more specifically, comprises Pt as a catalytic metal, Ba as a NOx absorbent, alumina as a carrier or support base material for carrying the Pt and Ba thereon, a Ce—Zr composite oxide as a promotor or auxiliary catalyst for absorbing oxygen and a hydration alumina binder. The in-between catalytic layer 3 comprises Pt and Rh as catalytic metals, zeolite as a carrier or support base material for carrying the Pt and Rh thereon and a hydration alumina binder. The outer catalytic layer 4 comprises a Ce—Zr composite oxide and a hydration alumina binder. Each of the in-between and outer catalytic layers contains Pt as a part of catalytic metal and Ba as a part of NOx absorbent. The Ce—Zr composite oxide is different in Zr concentration between the under catalytic layer 2 and the outer catalytic layer 4 and, more specifically, higher in the outer catalytic layer 4 than in the under catalytic layer 2 . In consequence, the acidity of Ce—Zr composite oxide is higher of the outer catalytic layer 4 than in the under catalytic layer 2 . [0025] An example exhaust gas purifying catalyst was prepared in the following process. [0026] A slurry was prepared by adding nitric acid to a mixture of alumina, a Ce—Zr composite oxide and hydrate alumina mixed at a weight ratio of 46.5:46.5:7. The nitric acid was added in order to adjust the potential of hydrogen (pH) of the mixture slurry between approximately 3.5 and 4. A honeycomb substrate 1 was dipped in the mixture slurry and then pulled out from the mixture slurry. After blowing off an excess of the mixture slurry from the honeycomb substrate 1 with air, the mixture slurry remaining applied on the honeycomb substrate 1 was dried at 150° C. for two hours and sintered at 500° C. for two hours so as thereby to be formed as an under catalytic layer 2 . Through the process, the total weight of alumina, Ce—Zr composite oxide and binder was adjusted to 320 g/L which corresponded to 80 weight % of the honeycomb substrate 1 . In the specification, the unit g/L is referred to the weight per one litter of the honeycomb substrate 1 . As the Ce—Zr composite oxide, CeO 0.6 Zr 0.4 O 2 , which had a Zr molar fraction, i.e. Zr/(Ce+Zr), of 0.4, was employed. The Ce—Zr composite oxide having a Zr molar fraction of 0.4 is hereafter referred to as an A-2 Ce—Zr composite oxide. A slurry was prepared by adding water and a zeolite (MFI) powder to a mixture of dinitro-diamine platinum solution and rhodium nitrate solution mixed so as to contain Pt and Rh at a weight ratio of 75:1. The total weight of Pt and Rh was adjusted to 24 g per 1 Kg zeolite. After drying the mixture slurry by a spray dryer, the mixture slurry was sintered at 500° C. for two hours to provide a Pt—Rh carrying zeolite powder. A slurry was prepared by adding water to the Pt—Rh carrying zeolite powder and hydrate alumina at a weight ratio of 85:15. The honeycomb substrate 1 formed with the under catalytic layer 2 was dipped in this mixture slurry and then pulled out from the mixture slurry. After blowing off an excess of the mixture slurry from the honeycomb substrate 1 with air the mixture slurry remaining applied on the honeycomb substrate 1 was dried at 150° C. for two hours and sintered at 500° C. for two hours so as thereby to be formed as an in-between catalytic layer 3 over the under catalytic layer 2 . Through the process, the total weight of Pt and Rh carried on the zeolite was adjusted to 20 g/L which corresponded to 5 weight % of the honeycomb substrate 1 . A slurry was prepared by adding water to a mixture of a Ce—Zr composite oxide and hydrate alumina at a weight ratio of 10:1. As the Ce—Zr composite oxide, Ce 0.4 Zr 0.6 O 2 whose Zr molar fraction was 0.6, was employed. The Ce—Zr composite oxide having a Zr molar fraction of 0.6 is referred to as an A-3 Ce—Zr composite oxide. The honeycomb substrate 1 formed with the under and in-between catalytic layers 2 and 3 was dipped in this mixture slurry and then pulled out from the mixture slurry. After blowing off an excess of the mixture slurry from the honeycomb substrate 1 with air, the mixture slurry remaining applied on the honeycomb substrate 1 was dried at 150° C. for two hours and sintered at 500° C. for two hours so as thereby to be formed as an outer catalytic layer 4 over the in-between catalytic layer 3 . Through the process, the total weight of ceria was adjusted to 100 g/L which corresponded to 25 weight % of the honeycomb substrate 1 . The honeycomb substrate 1 , on which the multiple catalytic layer, i.e. the under, in-between and outer catalytic layers 2 , 3 and 4 , was formed, was dipped in a mixture of a dinitro-diamine platinum solution and a barium acetate solution so as to be impregnated with 6 g/L Pt and 30 g/L Ba and then dried 150° C. for two hours and sintered at 500° C. for two hours. [0027] In order to assess NOx conversion efficiency and anti-SOx poisoning property of the exhaust gas purifying catalyst as an example of the invention, a comparative sample exhaust gas purifying catalyst was prepared by simply replacing the A-3 Ce—Zr composite oxide with a Ce—Zr composite oxide having a Zr molar fraction of 0.2, i.e. Ce 0.8 Zr 0.2 O 2 (which is hereafter referred to as an A-1 Ce—Zr composite oxide) or a Ce—Zr composite oxide having a Zr molar fraction of 0.9, i.e. Ce 0.1 Zr 0.9 O 2 (which is hereafter referred to as an A-4 Ce—Zr composite oxide) in the exhaust gas purifying catalyst described above. [0028] Impurities content of each of the example exhaust gas purifying catalyst according to the above embodiment and the comparative exhaust gas purifying catalyst was less than one weight %. The relationship between Zr molar fraction and ionic electric field strength for the A-1, A-2, A-3 and A-4 Ce—Zr composite oxides is shown in FIG. 2. [0029] Measurements of NOx conversion efficiency were performed by exposing the example exhaust gas purifying catalyst and the comparative exhaust gas purifying catalyst to simulated exhaust gas flowing at 150° C. at a space velocity SV of 55000 h −1 through a fluidized bed. Specifically, the simulated exhaust gas, which is specified in a table below, was altered in composition to a λ=1 state (which refers to the state of exhaust gas discharged when an air-fuel mixture of an excess air ratio λ of 1 is burnt) from a lean state (which refers to the state of exhaust gas discharged when a lean air-fuel mixture is burnt) once, kept in the λ=1 state for a specified period of time and thereafter returned to the lean state. The measurement was made to find NOx conversion efficiency for 130 seconds since the alteration to the lean state of the simulated exhaust gas. The result is shown as fresh NOx conversion efficiency in FIG. 3. Simulated Exhaust Gas Composition Component λ = 1 State Lean State HC(Plopylene) 4000 ppmC 4000 ppmC CO 0.16% 0.16% NO x 260 ppm 260 ppm H 2 650 ppm 650 ppm CO 2 9.75% 9.75% O 2 0.5% 7% N 2 Reminder Reminder [0030] Further in order to assess SOx-poisoned NOx conversion efficiency of the exhaust gas purifying catalyst of the invention, after subjecting the example exhaust gas purifying catalyst and the comparative exhaust gas purifying catalyst to SOx-poisoning, measurements of NOx conversion efficiency were made by the same manner as described above. SOx-poisoning was performed by exposing each exhaust gas purifying catalyst to an N 2 gas containing 200 ppm of SO 2 and 20% of O 2 flowing at 350° C. at a space velocity SV of 55000 h −1 through a fluidized bed for 30 minutes. The result is shown as SOx-poisoned NOx conversion efficiency in FIG. 3. [0031] As clearly seen in FIG. 3, it is recognized that the Ba as the NOx absorbent in the under catalytic layer 2 has been poisoned by Ba and SO 2 from the fact that each exhaust gas purifying catalysts shows a significant drop in SOx-poisoned NOx conversion efficiency. However, the example exhaust gas purifying catalyst in which the A-3 Ce—Zr composite oxide or the A-3 Ce—Zr composite oxide, which is higher in acidity than the A-2 Ce—Zr composite oxide, is contained in the outer catalytic layer 4 shows a higher SOx-poisoned NOx conversion efficiency and provides a lower drop ratio of NOx conversion efficiency due to SOx-poisoning than the comparative exhaust gas purifying catalyst in which the A-1 Ce—Zr composite oxide having a low acidity is contained in the outer catalytic layer 4 . In consequence, it is concluded that the acidity of the Ce—Zr composite oxide in the outer catalytic layer 4 affects NOx conversion efficiency and the increased acidity of the Ce—Zr composite oxide in the outer catalytic layer 4 is works effective with respect to anti-SOx poisoning property of the exhaust gas purifying catalyst. It is considered to be one of the causes that SO 2 in the exhaust gas is easy to be absorbed by the A-1 Ce—Zr composite oxide which is low in acidity and, however, is hardly absorbed by the A-3 Ce—Zr composite oxide or the A-3 Ce—Zr composite oxide, which is low in acidity. That is, the mechanism is considered to take the process of causing only a small amount of SO 2 to diffuses in the under catalytic layer 2 due to disturbance by the outer catalytic layer 4 , so as to prevent Ba in the under catalytic layer 2 from SOx-poisoning; causing NOx to pass through the outer catalytic layer, i.e. oxide layer, 4 without disturbance by the outer catalytic layer 4 , so as to be absorbed by Ba in the under catalytic layer 2 ; and permitting SO 2 to break away from Ba and escape through the outer catalytic layer 4 , so as to prevent SO 2 from accumulating in the under catalytic layer 2 . As a result of practical investigation of the sulfur concentration distribution in the SOx-poisoned exhaust gas purifying catalyst for which the utilization was made of X-ray images, it was found that while the SOx-poisoned example exhaust gas purifying catalyst showed a lower sulfur concentration in the under catalytic layer 2 than in the outer catalytic layer 4 , on the contrary, the SOx-poisoned comparative exhaust gas purifying catalyst showed a higher sulfur concentration in the under catalytic layer 2 than in the outer catalytic layer 4 . Further, it was found that the Ce—Zr composite oxide was desirable to have a molar fraction between 0.6 and 1.0 and, in particular, between 0.9 and 1.0 in view of refreshing and anti-SOx poisoning. [0032] In the light of the above discussion, it is grasped that making the outer catalytic layer 4 be a layer of the A-3 Ce—Zr composite oxide which is higher in acidity than the A-2 Ce—Zr composite oxide used as an auxiliary catalyst for oxygen adsorption in the under catalytic layer 2 is effective in improving an anti-SOx poisoning property. NOx that is absorbed by Ba in the under catalytic layer 2 while an air-fuel mixture remains lean (λ>1) is released when the air-fuel mixture is turned rich (λ≦1). The NOx that is released is deoxidized and reduced by Pt and Rh carried on zeolite in the in-between catalytic layer 3 as well as by Pr carried on alumina in the under catalytic layer 2 . The in-between catalytic layer 3 works to activate NOx and promote adsorption of NOx by Ba in the under catalytic layer 2 . [0033] Although the present invention has been fully described by way of the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the true scope of the present invention, they should be construed as included therein.	An exhaust gas purifying catalyst includes at least an under catalytic layer disposed on a substrate containing a NOx absorbent which absorbs NOx in exhaust gas under existence of oxygen, releases absorbed NOx when an oxygen concentration of exhaust gas lowers and is restrained from absorbing NOx by sulfur compounds in exhaust gas and an outer oxide layer disposed over the under catalytic layer and containing a Ce—Zr composite oxide.	1
CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority of Korean Patent Application No. 10-2011-0108673 filed on Oct. 24, 2011 in the Korean Intellectual Property Office, the entire contents of which are hereby incorporated by reference. BACKGROUND 1. Field The following description relates to a method and a system for implementing the wind information on the sea, that is, the sea-surface wind information, from satellite observation. 2. Description of the Related Art The sea-surface wind information is the very important information in various fields including preventive activities against a disaster, such as typhoon. For example, the sea-surface wind information can be utilized for the wind energy industry and is the very important information in marine activities including the fishery. In general, since the sea-surface wind strength is very closely associated with a physical change in the sea level resulting from it, a physical relation between them is derived to indirectly obtain the magnitude of the sea-surface wind. The sea-surface wind can be measured by direct observation using a buoy data or a ship, but it is impossible to monitor and observe the wide sea substantially in quasi-real time, and it can be said that only satellite observation is the only way to do so. In general, in order to observe the magnitude of the sea-surface wind by a satellite, sensors that can observe a wavelength range of microwave are needed, such as AMSR-E (Advanced Microwave Scanning Radiometer), SSM/I (Special Sensor Microwave/Imager), TMI (Tropical Microwave Imager). The physical state of the sea level has a very important effect on the emissivity of the sea level. In general, the sea has characteristics of low emissivity and high reflectivity. The wind on the sea level is one of main factors that increase the reflectivity and emissivity to change energy observed by a satellite. Many inventors have studied the characteristics for a long time, and the characteristics of sea-surface wind have been detected using an active microwave sensor, such as ASCAT, QUICKSCAT or by mounting a passive microwave sensor, such as SSM/I, AMSR-E, TMI on a satellite. Most of the studies have used a forward model based on very many known information items including the characteristics of wind and the sea level. However, these techniques have revealed a limit in obtaining the sea-surface wind information and have a problem with accuracy. SUMMARY Aspects of the present inventions relate to solving the problems described above. For example, illustrative implementations may provide a method of detecting sea-surface wind that enables the sea-surface wind information to be efficiently produced, using a satellite. In other words, aspects of the innovations may relate to a method and a system for producing the sea-surface wind information very quickly, e.g., in quasi-real time via an in-reverse conversion method by utilizing energy observed by a satellite as an input data, instead of the existing technique based on a forward model requiring many known information items. In such regard, present implementations may involve a method and a system for producing the sea-surface wind information by detecting the sea level roughness using the polarized property of electromagnetic wave based on a satellite data. In order to solve the problems described above, implementations may provide a system for estimating the wind strength as a function of the surface roughness, using a physical relation between the wind and the surface roughness. More specifically, some implementations may obtain emissivity or reflectivity by the ratio of the radiance temperature versus the temperature at sea level (hereinafter referred to as “sea level temperature”) as observed by a satellite, further calculates two reflectivity values observed or simulated by the vertical or horizontal polarized channels of microwave, and then estimates a surface roughness. Further, implementations may obtains the regression relation expression between the surface roughness and the wind strength, and then detect the sea-surface wind, using the information observed by the satellite again. According to implementations herein, the sea-surface wind information can be very accurately provided in quasi-real time based on satellite observation. As such, when a disaster including typhoon occurs, the innovations can be advantageously used. Further, implementations herein may benefit various industries and economy substantially by providing essential information to the wind energy industry and the fishing industry. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as described. Further features and/or variations may be provided in addition to those set forth herein. For example, the present invention may be directed to various combinations and subcombinations of the disclosed features and/or combinations and subcombinations of several further features disclosed below in the detailed description. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which constitute a part of this specification, illustrate various implementations and aspects of the innovations herein and, together with the description, help illustrate the principles of the present inventions. The file of this patent contains at least one drawing executed in color. Copies of this patent with color drawings will be provided by the Office upon request and payment of the necessary fee. In the drawings: FIG. 1 is a diagram illustrating an example of a system for detecting sea-surface wind according to the invention; FIG. 2 is a block diagram illustrating an example of a method of detecting the sea-surface wind information, using the system according to the invention; FIGS. 3 and 4 illustrate examples of implementing a software system for producing sea-surface wind according to the invention; FIG. 5 illustrates an example of a relation expression between the sea-surface wind speed and the sea level roughness by using a satellite microwave sensor; and FIGS. 6 a - 6 D illustrate the results of verifying the results of producting the sea-surface speed according to the invention. DETAILED DESCRIPTION Hereinafter, a configuration and an effect according to the invention are described in detail by reference to the accompanying drawings. In describing the invention by reference to the accompanying drawings, the same components are provided with the same reference numerals throughout the entire figures, and description thereof will not be repeated. Although the terms of a first, a second or so can be used for describing various components, the components should not be limited to the terms. The terms are used only for the purpose of distinguishing one component from the others. FIG. 1 is a diagram illustrating an example of a system for detecting sea-surface wind according to the invention, and FIG. 2 is a block diagram illustrating an example of a method of detecting the sea-surface wind information, using the system according to the invention. Referring to FIGS. 1 and 2 , the system for detecting sea-surface wind according to the invention can comprise an observation sensor 110 that senses the radiance temperature of sea water or the sea level temperature using a sensor mounted on a satellite, a reflectivity measurement operation unit 120 that produces polarized a light-specific reflectivity using the radiance temperature or the sea level temperature transmitted from the observation sensor unit 110 , a sea level roughness determination unit 130 that determines the sea level roughness by using the polarized light-specific reflectivity produced by the reflectivity measurement operation unit 120 , and a sea-surface wind information production unit 140 that determines a relation between the produced sea level roughness and the magnitude of sea-surface wind and produces the sea-surface wind information. In this case, the observation sensor unit 110 is of a concept that includes an observing module including an observation sensor unit of a satellite, and a polar orbit satellite data in US referred to as AQUA is used as an example herein. It is a satellite data is commonly used for observing sea-surface wind and producing the sea-surface wind information. In addition, most of the observation sensor units use microwave sensors, which are mounted on polar orbit satellites due to the characteristics of such microwave sensors. For example, the AMSR-E sensor of an Aqua satellite, a polar orbit satellite, and the SSM/I observation data of the DMSP satellite are widely used all over the world. As an observation channel, 6.9 GHz, 10 GHz, 19 GHz or the like is used. Observation can be carried out over microwave channels in a wavelength range with higher frequencies, but in this case accuracy becomes gradually lower. The reflectivity measurement operation unit 120 produces a polarized light-specific reflectivity using the radiance temperature or the sea level temperature transmitted from the observation sensor unit 110 . In other words, the reflectivity measurement operation unit determines a polarized light-specific reflectivity using the observed radiance temperature and the sea level temperature. Equation 1 below is widely used for obtaining the reflectivity of sea level from satellite observation all over the world. R R =( T B −T ↑ −T S ·Γ)·[{ T ↓ (1+Ω)− T S }·Γ] −1 [Equation 1] wherein, R R represents a reflectivity, T S represents a sea level temperature, T B represents a radiance temperature observed over a microwave channel of AQUA AMSR-E, and T ↑ and T ↓ are terms showing an atmospheric effect. Γ represents an atmospheric transmittance. The fit parameter Ω is a correction parameter representing how much T ↓ is scattered. In addition, the sea level roughness determination unit 130 determines the roughness of the sea level using the polarized light-specific reflectivity produced by the reflectivity measurement operation unit 120 . Specifically, the roughness of the sea level is measured by Equation 2 below, which comprises the wavelength, the satellite zenith angle, and the vertical and horizontal reflectivities of the observed channel, using the polarized light-specific reflectivity produced by the reflectivity measurement operation unit. σ ≈ λ 4 ⁢ π ⁢ ⁢ cos ⁢ ⁢ θ · ln ⁡ ( R R , H se ⁢ ⁢ c 2 ⁢ θ R R , V ) [ Equation ⁢ ⁢ 2 ] (wherein, R V is a component of polarized light in reflectivity and represents a vertical reflectivity in vertical polarization of light, and R H is a component of polarized light in reflectivity and represents a horizontal reflectivity in horizontal polarization of light. R R represents the observed polarized reflectivity, and θ represents a satellite zenith angle.) When the producing system according to Equation 2 described above is used, the roughness of a sea-surface wind is very accurately detected. In addition, the sea-surface wind information production unit 140 determines a relation between the produced roughness of the sea level and the magnitude of the sea-surface wind and produces the sea-surface wind information. Specifically, it is a relation expression between the sea-surface wind and the roughness of the sea level, which was obtained using FASTEM-2, the earth surface/sea level information module of the radiation transfer model used in various satellite obserbations in US and Europe, as in Table 1 below. The linear regression equation was used, and information items were classified according to the wind strength and the observed wavelength. In this case, AMSR-E sensors are classified into 6.9, 10, 18 GHz channels and the wind strength is classified into weak wind (below 5 m/s), mesoscale wind (5-10 m/s), and strong wind (over 15 m/s). TABLE 1 Channel SSW Slope Offset 6.9 GHz <5 ms −1 0.00786484 0.0182238 5~15 ms −1 0.00665046 0.0233580 >15 ms −1 0.00745813 0.0121359 10 GHz <5 ms −1 0.00515418 0.0127663 5~15 ms −1 0.00436252 0.0162764 >15 ms −1 0.00489410 0.00890625 18 GHz <5 ms −1 0.00363695 0.00990545 >5 ms −1 0.00277569 0.0139433 In Table 1, SSW, slope and offset mean a wind strength, a gradient and an intercept value, respectively. These coefficients were obtained using the linear regression equation, the FASTEM-2 model and GDAPS (Global Data Assimilation and Prediction System) data. The result of utilizing them is shown in FIG. 1 . In particular, when the system described above is used, the sea-surface wind strength is very accurately detected. A method of detecting sea-surface wind by using the system according to the invention is described using a block diagram in FIG. 2 . First, a relation expression (or a look-up table) between the sea level roughness and the sea-surface wind is prepared, polarized light-specific reflectivities by seal level channels are produced using the radiance temperature measured by a satellite, a roughness is operated on the basis of the produced reflectivity, and the sea-surface wind information is determined using the relation expression (or the look-up table) wherein the sea level roughness as an input data. As described above, the invention can implement a method of detecting the sea-surface wind comprising a section that prepares a relation expression (or a look-up table) between the sea level roughness and the sea-surface wind, a section that detects the sea level roughness, and a section that produces the sea-surface wind, and the sea-surface wind detection system by software. Therefore, the system and the method according to the invention can be configured as software, which can be manufactured in the form of a computer-readable record medium in which a software program to execute them is contained. FIGS. 3 and 4 illustrate examples of implementing the software system for producing the sea-surface wind according to the invention. FIG. 5 illustrates an example of a relation expression between the sea-surface wind speed and the sea level roughness by using a satellite microwave sensor. The result of using the AMSR-E sensor is shown in FIG. 5 . Specifically, FIG. 5 represents a relation between the produced sea-surface wind speed and the sea level roughness by channels by using observations of AMSR-E of AQUA, the polar orbit satellite operated by USA. For input information of wind, GDAPS data, which are the numeric model results published by Korea Meteorological Administration. Among the data published four times a day, GDAPS data corresponding to 06 UTC on Feb. 24, 2009 were used. In order to calculate the sea level emissivity, FASTEM-2, which is the latest land/sea module of the radiation transfer model of the next generation satellite operated by USA and Europe, was used, and it is also used for verifying the accuracy of the inverse conversion method according to the invention. FIGS. 6A-6D illustrate the results of verifying the results of producting the sea-surface speed according to the invention. For such verification, GDAS data, which are the numeric model results of USA, was used. [(a) GDAS SSW on Apr. 11, 2011, GDAS SSW—Retrieved SSA for AMSR-E (b) 6.9 GHz, (c) 10 GHz and (d) 18 GHz channels.] In other words, FIGS. 6A-6D represent examples of producing the sea-surface wind information by using the relation expression obtained in FIG. 5 and thereby using satellite data, and shows the result of verifying the method presented above. For such verification, the numeric model result (GDAS) data, which were presented by National Oceanic and Atmospheric Administration in USA, were used, and the data corresponding to 06 UTC on Apr. 10, 2011, a different date from that in the previous example, was selected. The reason why the date and the meteorological organization were made to be different from those in the previous example is to demonstrate that the invention is well applicable to any wind information. Consequently, the invention obtained results with much higher accuracy than the conventional sea-surface wind information observed by a satellite, which was cited in international papers and is used on the job site in foreign countries. For 6.9 GHz and 10 GHz of AMSR-E and 19 GHz of SSM/I, a difference (error) between the inputted wind information and the produced wind information was found to be approximately within 0.1 m/s, and RMSE (Root Mean Square Error) was found to be within 0.29 m/s. It can be known that in the aspect of accuracy, such result is very higher than the conventional sea-surface wind information production algorithm result (approximately, an error is 0.5 m/s, RMSE is 1.5 m/s) used in foreign countries. In other words, it can be identified that when the system according to the invention described above is used, the sea-surface wind strength is very accurately detected. The term “unit” used for describing many components according to the invention means a software component or a hardware component such FPGA or ASIC, and the “unit” performs a certain function. However, the “unit” does not have a meaning to be limited to software or hardware. The “unit” can be configured so that it may be present in an addressable storage medium and one or more processors may be played back. Therefore, as an example, the “unit” comprises software components, object-oriented software components, class components, task components, processes, functions, attributes, procedures, subroutines, segments of program codes, drivers, firmware, microcode, circuit, data, database, data structures, tables, arrays, and variables. Functions provided within the components and “units” can be combined into a smaller number of components and “units”, or divided into additional components and “units” increase. In addition, components and “units” can be implemented so that one or more CPUs may be played back in a device or a security multimedia card. In the detailed description of the invention as described above, specific embodiments were described. However, many modifications can be made within the scope of the invention. The technical idea of the invention should not be limited to the embodiments described herein, while it should be defined by the following claims and further equivalents to them. DESCRIPTION OF REFERENCE NUMERALS 110 Observation Sensor Unit 120 Reflectivity Measurement Operation Unit 130 Sea Level Roughness Determination Unit	Systems and methods are provided that involve obtaining emissivity and reflectivity by the ratio of the radiance temperature versus the sea level temperature as observed by a satellite, and may further calculate two reflectivity values observed or simulated by the vertical or horizontal polarized channels of microwave, and then estimate a surface roughness. Further, illustrative implementations may involve obtaining the regression relation expression between the surface roughness and the wind strength and then detecting the sea-surface wind, using the information observed by the satellite again. As such, the sea-surface wind information can be obtained through satellite observation, and the information can be utilized for preventive activities against disaster including typhoon, the energy industry including wind power and the fishery in quasi-real time.	8
RELATED APPLICATIONS This application is a division of application Ser. No. 09/158,603, filed on Sep. 23, 1998, which is a nonprovisional application of Ser. No. 60/099,666, filed Sep. 9, 1998. FIELD OF THE INVENTION The present is directed to an ultraviolet curing apparatus using an inert atmosphere chamber to exclude the presence or oxygen during the curing process. The present invention is also directed to a removable nozzle cartridge with adjustable nozzles for delivery of inert gas, such as nitrogen, into a curing chamber. BACKGROUND OF THE INVENTION It is well known to apply ultraviolet curable coating to various types of object and to expose the same to ultraviolet radiation to produce a cured coating with desirable properties. For some curing chemistries, the presence of oxygen tends to inhibit the curing process, and so for such chemistries the amount of oxygen must be controlled. A common way of accomplishing this is to provide a curing chamber in which a flow of nitrogen is used to display the oxygen so that an inert atmosphere is provided. A curing chamber is a relatively large and expensive structure, costing in the order of $150,000. The inert gas is introduced into the chamber by a variety of nozzles which are typically permanently secured to the chamber framework. When an improvement occurs in the nozzle technology, a brand new curing chamber would have to be built to incorporate the improvement, making the existing one obsolete. There is, therefore, a need for a curing chamber where the nozzles are removably secured to the chamber structure so that when improvement occurs in the nozzle technology, the existing chamber can be retrofitted with the new nozzles. Prior art curing chambers are typically built for specific applications, such as using a specific ultraviolet processor for curing a product traversing through the chamber at a specific speed. If the user desires to increase the curing speed to cure more products per given time, the existing curing chamber may not be adequate, since the nozzles built into the machine may not be adequate to maintain the required inert atmosphere at the higher speed. In this case, the user would either deliver increased amount of nitrogen into the chamber to compensate for the increased speed or invest in a new curing chamber, requiring additional investments and space. Increasing the amount of nitrogen delivered to the curing chamber to accommodate the new application is relatively expensive, since nitrogen is an expensive commodity. There is, therefore, a need for a curing chamber where the nozzles can be changed or adjusted without replacing the entire curing chamber to accommodate the user's new application, without increasing nitrogen consumption or purchasing a new curing chamber. OBJECTS AND SUMMARY OF THE INVENTION It is an object of the present invention provide a an inert gas curing chamber where the gas delivery system is removable so that the curing chamber can be used for different product runs. It is another object of the present invention to provide a gas delivery system to a curing chamber that is in cartridge form so that it can be easily removed or replaced as desired or different applications. It is still another object of the present invention to provide a gas delivery system for a curing chamber that provides a relatively uniform flow distribution across the path of the product being cured. It is yet another object of the present invention to provide a gas delivery system for a curing chamber wherein the direction of gas flow coming from the system can be adjusted to accommodate increased product travel speed within the chamber without increasing gas consumption. It is still further another object of the present invention to provide a gas delivery system for a curing chamber that is removable from the chamber so that adjustments to the system can be made outside of the chamber. In summary, the present invention provides a curing apparatus comprising a curing chamber for accommodating a controlled atmosphere for a product being treated and an irradiator for providing radiation directed at the product. The curing chamber has spaced inlet and outlet openings for the product establishing a path of travel underneath the irradiator. First and second nozzle assemblies are disposed adjacent respective inlet and outlet openings for supplying inert gas into the chamber and maintaining an inert atmosphere within the chamber. The nozzle assemblies are removably secured to the chamber. A pre-chamber is provided in the nozzle assemblies to moderate the pressure distribution of the gas within the nozzle assemblies. These and other objects of the present invention will become apparent from the following detailed description. BRIEF DESCRIPTIONS OF THE DRAWINGS FIG. 1 is a side elevational view of a curing chamber made in accordance with the present invention. FIG. 2 is a fragmentary view of the curing chamber of FIG. 1, showing a nozzle cartridge being replaced or taken out from the curing chamber. FIG. 3 is a perspective view of the nozzle cartridge shown in FIG. 2 . FIG. 4 is a perspective assembly view of the nozzle cartridge of FIG. 3 . FIG. 5A is a cross-sectional view taken along line 5 A— 5 A in FIG. 4 . FIG. 5B is a cross-sectional view taken along line 5 B— 5 B of FIG. 5 A. FIG. 6 is a cross-sectional view taken along line 6 — 6 in FIG. 3 . FIG. 7 is similar to FIG. 6, showing the nozzle bodies adjusted to different angular positions from the vertical axis. FIG. 8 is a fragmentary view, partly in cross-section, of the nozzle cartridge of FIG. 4, showing details of the endcaps of the pipe nozzle assembly. FIG. 9 is a schematic illustration of pressure distribution in the pre-chamber and final chamber along the length of the distribution slot of the nozzle cartridge of the present invention. DETAILED DESCRIPTION OF THE INVENTION An ultraviolet curing apparatus R made in accordance with the present invention is disclosed in FIG. 1 . The apparatus R includes a chamber 2 in which ultraviolet curing of a product is done. The chamber 2 has an inlet opening 4 and an outlet opening 6 through which the product is conveyed into the chamber by means of a web 7 . A pair of rollers 8 pull the web 7 through the chamber 2 . An irradiator 10 , such as a standard ultraviolet lamp, is used to provide the curing process for the product. The irradiator 10 includes a bulb 12 disposed within a reflector cavity 14 . Nozzle cartridges 16 and 18 are disposed within the chamber across the width of the web 7 and adjacent the inlet and outlet openings 4 and 6 , respectively, to provide a curtain barrier of an inert gas at the respective openings and to flood the interior of the curing chamber 2 with the same inert gas, preferably nitrogen, to exclude oxygen during the curing process of the product when it is subjected to the ultraviolet radiation of the bulb 12 . The nozzle cartridges 16 and 18 are identical to each other, except each is shown turned 180° with respect to the other. Although each of the nozzle cartridges 16 and 18 is disclosed as having a slot nozzle assembly 20 and a pipe nozzle assembly 22 , each cartridge may also carry only one nozzle assembly, depending on the specific application. The slot nozzle assembly 20 , which is disposed closer to the respective inlet or outlet opening is used to provide a curtain barrier of inert gas to isolate the interior of the curing chamber 2 from the outside. The pipe nozzle assembly 22 is used to flood the chamber 2 with the inert gas. The nozzle cartridges 16 and 18 are removably secured to the curing chamber 2 by means of screws 24 , as best shown in FIG. 2 . An opening 26 on top at each end of the curing chamber 2 is adapted to accommodate the nozzle cartridges 16 and 18 into the curing chamber 2 . Each of the nozzle cartridges 16 and 18 includes a top plate or support 28 to which the slot nozzle assembly 20 and the pipe nozzle assembly 22 are secured. A plurality of holes 30 around the outer edge of the plate 28 accommodate respective screws 24 , which are used to secure the nozzle cartridge in the opening 26 of the curing chamber 2 , as best shown in FIG. 3 . The removability of the nozzle cartridges 16 and 18 from the curing chamber 2 advantageously provide the user with flexibility when a change in application of the curing chamber occurs, such as when the web speed is desired to be increased to accommodate a different product, without purchasing another curing chamber. Further, the removability of the cartridges from the curing chamber means that the cartridges can be adjusted on the workbench, which is a much easier operation than if the nozzle assembly is adjusted inside the curing chamber. Also, several previously adjusted cartridges can be stored aside that are then easily installed whenever the need arises for their use on a different application, thereby minimizing downtime in the job. The nozzle cartridge 18 , which is identical to the cartridge 16 except that they are shown 180° apart, is shown in an assembly view in FIG. 4 . The slot nozzle assembly 20 includes a nozzle body 32 , endcaps 34 , shims 36 and connectors 38 . The connectors 38 are threadedly secured to the respective endcaps 34 through respective openings 37 in the plate 28 to thereby secure the endcaps 34 to the plate 28 . Screws 39 secure the endcaps 34 to the respective ends of the nozzle body 32 to form an integral pre-chamber 41 within the nozzle body 32 . The connectors 38 are used to connect the nozzle assembly to an inert gas supply. The pipe nozzle assembly 22 includes a nozzle body 40 , a pipe diffuser 42 , endcaps 44 and connectors 46 . Screws 50 secure the endcaps 44 to the sides of the nozzle body 40 to form an enclosed pre-chamber 52 . The connectors 46 are threadedly secured to the respective endcaps 44 through respective openings 43 in the plate 28 . The connectors 46 are used to connect the nozzle assembly to an inert gas supply. Studs 54 extending from the top surface of the plate 28 are configured to store unused shims 36 . Screws 55 secure the top part of the endcaps 34 to the top plate 28 . The pipe diffuser 42 has a linear array of holes 56 disposed along the length and side of the pipe diffuser 42 facing the nozzle body 40 . Another linear array of smaller holes 58 are disposed on the diametrically opposite side of pipe diffuser 42 , as best shown in FIGS. 5A and 5B. A pair of handles 60 disposed at respective end portions of the plate 28 allow the user to conveniently handle the cartridge when removing or replacing it in the curing chamber 2 . Each of the endcaps 34 has an L-shaped passageway 62 to allow the flow of the inert gas from the connector 38 to the pre-chamber 41 . Similarly, each of the endcaps 44 also includes an L-shaped passageway 64 to allow the flow of the inert gas from the connectors 46 to the pre-chamber 52 . The slot nozzle body 32 is made from two identical castings 66 , which are joined together by a plurality of bolts 68 . An interior longitudinal distribution slot 70 is formed between the pair of casting 66 along the length of the pre-chamber 41 in communication therewith. An exit slot 72 is also formed between the two castings 66 at the lower portions thereof to allow the inert gas to flow out into the curing chamber and form a curtain barrier. A final chamber 74 is provided by the castings 66 and is disposed between the slots 70 and 72 and runs along the length thereof. The distribution slot 70 allows the inert gas from the pre-chamber 41 to flow to the final chamber 74 . A plurality of bolts 76 and springs 78 provide a means for adjusting the gap of the exit slot 72 as desired for a specific application. Turning the bolts 76 in either direction will either decrease or increase the gap of the exit slot 72 . The springs 78 urge the castings 66 away from each other so that when the bolts 76 are turned counter-clockwise in a conventional unscrewing direction, the castings 66 will move a corresponding distance under the spreading force of the springs 78 . The slot nozzle body 32 is secured to the underside of the plate 28 by means of a bracket 80 and a resilient member 82 that advantageously allows the nozzle body 32 to be angularly adjusted. The shims 36 are used to adjust the height of the exit slot 72 above the rollers 8 , as best shown in FIG. 1 . The nozzle body 40 includes an arcuate wall 84 conformed to the diameter of the pipe diffuser 42 , as best shown in FIG. 6 . The arcuate wall 84 is used to support the pipe diffuser 42 . A longitudinal opening 86 is disposed in a top portion of the arcuate wall 84 and extends along the length of the pipe diffuser 42 to thereby expose the holes 56 to the pre-chamber 52 , as best shown in FIG. 6 . The end portions of the pipe diffuser 42 are received in respective bore holes 88 and endcaps 44 where set screws 90 permit the pipe diffuser 42 to be angularly adjusted and locked in place (see FIG. 8) A gasket 92 is disposed around the underside periphery of the plate 28 to provide a seal around the opening 26 when the nozzle assembly is secured in place to the frame of the curing of the curing chamber 2 . The nozzle body 32 includes a plurality of screw-receiving slots 98 and 100 , as best shown in FIGS. 6 and 7, that are aligned with respective holes 102 and 104 and are used to provide angular positioning of the nozzle body 32 to change the direction of flow of the inert gas exiting from the exit slot 72 . When the holes 102 are used in conjunction with the screw-receiving slots 98 when attaching the nozzle body 32 to the endcaps 34 , the exit slots 72 would be directed downwardly at zero degree to the vertical. If the holes 104 are used with the screw-receiving slots 100 , the nozzle body 32 and the exit slots 72 would be positioned at an angle from the vertical toward the inlet opening 4 in the case for the cartridge 16 . The range of adjustment for the pipe diffuser 42 is 0°-45° with respect to a vertical axis. The opening 86 in the arcuate wall 84 is configured for the maximum angular adjustment without interfering with the holes 56 . The angular positioning of the exit slot 72 and the pipe diffuser 42 will depend on the specific application. Preferably, the slot nozzle 72 for the nozzle cartridge 16 adjacent the inlet opening 4 is preferably directed at an angle toward the inlet opening, while the pipe diffuse 42 would be preferably angled toward the center of the curing chamber 2 . The exit nozzle 72 for the nozzle cartridge 18 would be preferably directed perpendicularly toward the web 7 , while the pipe diffuser 42 would be preferably directed toward the center of the curing chamber. The pre-chamber 41 advantageously provides for an even flow of inert gas along the length of the exit slot 72 . In the prior art, in order to obtain an even distribution of flow, multiple feeds are provided along the length of the manifold. With the present invention, even distribution of flow is achieved with only two feeds, one at each end of the nozzle body 32 through the connectors 38 . The gas flow is substantially made more uniform as it flows from the pre-chamber 41 to the final chamber 74 through the distribution slot 70 . The pre-chamber 41 advantageously provides a moderating effect to the pressure distribution within the final chamber 74 . This is schematically illustrated in FIG. 9, where a variation of less than 10% along the length of exit slot 72 is achieved with the present invention. In the prior art, about 30% variation in flow rate along the slot length is typical. With the present invention, an inert atmosphere of approximately 50 ppm of oxygen is achieved. The pre-chamber 52 in the pipe nozzle body 40 also provides for even flow of inert gas along the length of the pipe diffuser 42 as the gas exit through the linear array of exit holes 58 . The variation of pressure within the pre-chamber 52 alone the length of the pipe diffuser 42 is also illustrated schematically in FIG. 9, where about 30% variation in the pre-chamber 52 is reduced substantially to about 10% inside the pipe diffuser 42 prior to the gas exiting through the exit holes 58 . The pre-chamber 52 advantageously provides a moderating effect to the pressure distribution within the interior of the pipe diffuser 42 . The angular adjustment to the pipe diffuser 42 advantageously permits the curing chamber 2 to accommodate higher web speed. In the prior art, the flow rate of the inerting gas is increased for higher web speed, resulting in higher gas consumption, which in the case of nitrogen could be fairly expensive. With the present invention, adjusting the angle of flow through the pipe diffuser 42 while maintaining the flow rate of the gas feeds through the connectors 46 would still maintain the inerted atmosphere at the higher web speed. At higher web speed, the pipe diffuser 42 would be angled toward the flow of the web at a larger angle from the vertical than at lower web speed. With 15 ppm oxygen of inert gas being introduced to the chamber, 50 ppm oxygen atmosphere can be maintained with the present invention. Maintaining a uniform distribution of inert gas within the chamber, for example at 50 ppm oxygen, is important to the proper curing of the product being cured. If the inert atmosphere varies across the product, then the material properties of the product would vary depending on the variation on the inert atmosphere across the product when it is subjected to the UV radiation. With the cartridge design of the present invention, the nozzle assemblies 20 and 22 can be pre-adjusted outside the curing chamber for a specific application or job. When a different job is desired to be processed through the chamber, a nozzle assembly which has already been adjusted for that job would be used to replace the one that is in the machine. In this manner, a low level technician can perform the change-over, since no further adjustments to the nozzles would be needed. In the prior art, where adjustments has to be made in the machine, a high level technician or engineer would be required to make the adjustment. Although the present invention has been described using an ultraviolet irradiator, other types of irradiators, such a thermal heater, would be equally applicable. While this invention has been described as having preferred design, it is understood that it is capable of further modification, uses and/or adaptations following in general the principle of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains, and as may be applied to the essential features set forth, and fall within the scope of the invention or the limits of the appended claims.	A curing apparatus comprises a curing chamber for accommodating a controlled atmosphere for a product being treated and an irradiator for providing radiation directed at the product. The curing chamber has spaced inlet and outlet openings for the product establishing a path of travel underneath the irradiator. First and second nozzle assemblies are disposed adjacent respective inlet and outlet openings for supplying inert gas into the chamber and maintaining an inert atmosphere within the chamber. The nozzle assemblies are removably secured to the chamber. A pre-chamber is provided in the nozzle assemblies to moderate the pressure distribution of the gas within the nozzle assemblies.	5
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is the United States national phase application of International Application No. PCT/EP05/12099 filed on Nov. 11, 2005 and claiming a priority date of Nov. 29, 2004, which is incorporated herein by reference. FIELD OF THE INVENTION [0002] The present invention pertains to a fuel injection method that utilizes an accumulator principle, particularly a common rail principle, as well as to a fuel injection device for a reciprocating internal combustion engine according to an accumulator principle, particularly according to the common rail principle. BACKGROUND OF THE INVENTION [0003] WO 01/14713 A1 discloses a fuel injection device in which fuel is injected with a least two different fuel pressures by means of injectors. The fuel injection should be pressure-controlled at the higher fuel pressure in this case. For this purpose, a control chamber of the fuel injection valve features a connection to a line with a fuel pressure. In addition, a pressure booster is arranged upstream of the injection valve and is controlled by a solenoid valve analogous to the injection valve. Due to the proposed device and the method in which this device is used, the injection nozzle is under the pressure of at least the associated common rail at all times. SUMMARY OF THE INVENTION [0004] The invention is based on the objective of achieving an improved injection in which, in particular, an injection nozzle can be rapidly opened and closed and the injection can be realized more flexibly such that metering of the quantity to be injected can be improved and an injection sequence can be defined. [0005] This objective is attained with a fuel injection method with the characteristics of claim 1 , with a fuel injection device with the characteristics of claim 10 , and with a fuel injection device with the characteristics of claim 12 . Other advantageous configurations and additional developments are defined in the respective dependent claims. [0006] A fuel injection method according to the invention that utilizes an accumulator principle, particularly a common rail principle, is characterized in that fuel arriving from an accumulator, particularly a common rail, is conveyed to a primary side of the pressure booster at a first pressure such that a secondary side of the pressure booster is subjected to a pressure increase, and in that an opening and closing of an injection nozzle are realized with the pressure in a pressure chamber for the injection nozzle, by displacing a closing element that acts upon the injection nozzle, particularly an injector needle, by means of a hydraulically controlled pressure change. [0007] This makes it possible to achieve an increase in the maximum attainable injection pressure by means of the pressure booster. In addition, the hydraulic control of a pressure change males it possible to rapidly open as well as rapidly close the injection nozzle. The quantity to be injected can furthermore be metered in an extremely precise fashion with minimal pressure changes. It is possible, in particular, to attain injection rates that are comparable to those of conventional pump-injector systems. [0008] Since corresponding pressure drops and pressure increases have very rapid effects due to the hydraulic pressure transmission, this advantage of the pump-injector principle, namely a precisely metered injection sequence, can be combined with the flexibility of a common rail system. Characteristics such as pre-injection and post-injection can be adapted to at least one main injection with respect to the quantity as well as the time, particularly with a hydraulic control of the pressure only. In addition, instead of main injection, a timed injection can also be realized during an injection phase that can be adapted to various operating ranges of the internal combustion engine, for example, with the aid of corresponding characteristic diagrams. [0009] According to a first configuration of the invention, this fuel injection device is connected to the one proposed in WO 01/53688, the full content of which, with respect to the fuel injection device as well as the individual components and methods, is hereby incorporated into this publication by reference. As mentioned above, the pressure booster is preferably arranged between the control valve and the injection nozzle, wherein according to one configuration the hydraulic control of the pressure chamber for the injection nozzle features a direct connection to the control element. [0010] According to another configuration, a pressure in excess of 2000 bar is generated on the secondary side. This can be realized, for example, if a pressure in excess of 1500 bar acts upon the primary side. According to another configuration, a ratio between primary pressure and secondary pressure is adjusted which lies between 1:1.2 and approximately 1:4, preferably between 1:1.8 and approximately 1:3, particularly between approximately 1:1.5 and approximately 1:3. For this purpose, the pressure booster is preferably realized in the form of a piston that features different surface areas on the primary and the secondary side, e.g., as described in the above-mentioned publication WO 01/14713. In this respect, we refer to the disclosure of this publication. It is advantageous for the pressure intensification ratio to be smaller than 3 such that it is possible to realize a small rail volume on the one hand and a small control valve cross section on the primary side as well as a small supply line cross section on the other hand. An advantageous design of the line cross sections can be realized based on a pressure intensification ratio of the pressure booster. Corresponding indications are provided further below with reference to a few examples, wherein these indications, however, are not limited to the respective configuration. [0011] According to another configuration, the pressure chamber is subjected to a second pressure generated on the secondary side, wherein the hydraulically controlled pressure change acts upon the primary side of the pressure booster. This allows a particularly fast reaction between the initiation of a pressure change and the change of an injection behavior. It is particularly preferred for a fuel injection pressure realized by means of the hydraulically controlled pressure change to follow a valve stroke of a control valve immediately. [0012] According to one additional development, a pressure on the secondary side is decreased by discharging fuel into a low-pressure chamber in order to close an injection nozzle. Due to this measure, the required sealing surfaces of the injection system, particularly for closing the injection nozzle on the secondary side, are invariably subjected to pressure for brief periods of time only. This furthermore makes it possible to quickly change the injection sequence and, in particular, to precisely meter the fuel to be injected. If a high pressure continuously acts upon the injection nozzle, leaks could develop in the region of the sealing surfaces between the nozzle and the upper part of the injector. Moreover, if a uniformly high pressure permanently acts upon the injection nozzle, the control and regulation precision of the injected amount, necessary for possibly required injection profiles, would be difficult to realize because it would be necessary to open and close the injection nozzle even faster. The option of decreasing the pressure on the secondary side, in contrast, also makes it possible to realize increasing and decreasing characteristics of injection into die combustion chamber. [0013] In other respects, the method can also be carried out such that the actuating times for the fuel injection can be purposefully shortened with the aid of pressure feedback. [0014] According to another configuration, a control element that is arranged downstream of the accumulator and upstream of the pressure booster is acted upon with the second pressure from the secondary side of the pressure booster. This makes it possible, for example, to also utilize the injection pressure for controlling the fuel injection. A higher metering accuracy can also be achieved in this fashion. [0015] It is furthermore possible to act upon a control element that is arranged downstream of the accumulator and subjected to a control pressure in a control line that is delivered by the accumulator and subsequently influenced with the second pressure from the secondary side of the pressure booster, wherein the control pressure determines the connection of the second pressure to a low-pressure chamber. [0016] According to one additional development, one or more damping volumes, particularly throttle points, are provided in order to at least damp possibly occurring oscillations to such a degree that they do not interfere with the desired injection sequence. For example, an oscillation in a control chamber of the control element and in a pressure supply line can be reduced with a throttle. A throttle can furthermore be provided in order to absorb or at least damp undesirable pressure waves in the fuel injection device. [0017] In addition, one or more throttles can be used to purposefully build up the fuel pressure. This can be used, in particular, for achieving accelerated switching times, for example, with respect to the closing element acting upon the injection nozzle. For example, a throttle point can be connected to an evacuation chamber that is arranged opposite from the injection nozzle is and separated by the closing element. The throttle point is arranged between the evacuation chamber and the low-pressure chamber. It ensures a delayed pressure drop from the evacuation chamber into the low-pressure chamber such that, for example, cavitation can be prevented in the region of the injection nozzle, particularly during closing. The throttle point can simultaneously generate backpressure when the pressure in the evacuation chamber for the injection nozzle is increased, such that a faster response with respect to the displacement of the closing element is achieved. [0018] In order to improve the shaping of the injection sequence, the conventional monotonic voltage control of the first control element could also be replaced with a timed voltage control such that the ensuing second control element, the pressure booster and the injection nozzle are timed in a hydraulically controlled fashion. In this case, the timing is preferably adapted to an operating range. [0019] The invention also proposes a fuel injection device with an accumulator, particularly according to the common rail principle, for a reciprocating internal combustion engine, wherein said fuel injection device features an injection nozzle and an injector part, wherein the injector part has a pressure chamber in which a closing element for closing the injection nozzle is guided, wherein the pressure chamber is connected via a connecting channel to a pressure booster that is arranged downstream of an accumulator, particularly a common rail, and upstream of the pressure chamber, and wherein the valves of the fuel injection device that are arranged downstream of the accumulator and serve to control the fuel flow are, with the exception of a first control element, in particular a valve, controlled hydraulically by the control valve. Due to this control principle, it is not necessary to provide, in particular, two independently controlled adjusting elements in order to control, for example, a pressure booster and an injector needle. On the contrary, a single control element, with the aid of the effective cross sections of lines, components and of other forces such as, for example, spring forces and hydraulic forces, makes it possible to realize the desired injection profile. [0020] The accumulator consists of a pressure accumulator in which the fuel is under pressure. The accumulator can be supplied with fuel continuously or a discontinuously, for example, with the aid of a pump system. The accumulator can be connected, for example, to only one injection nozzle or to several injection nozzles by means of corresponding control lines in order to respectively supply these injection nozzles with fuel. The term “accumulator” therefore also includes, in particular, the injection systems for Otto cycle as well as for Diesel cycle engines known as common rail systems. [0021] A corresponding electronic control of the control element, for example, makes it possible, namely in connection with an engine control to immediately react to the particular load status of the reciprocating internal combustion engine with a suitable fuel injection. An improved, and in particular more flexible, injection profile is achieved if the pressure chamber is connected to a low-pressure chamber via a pressure relief connection. The low-pressure chamber may consist, for example, of a tank or another container or a large-volume line capable of lowering the pressure at the injection nozzle by taking up fuel volumes. The fuel flow to be controlled is preferably so small that no back pressure occurs in a low-pressure system that comprises the low-pressure chamber. The low-pressure chamber or the low-pressure system is respectively realized, in particular, in the form of an “unpressurized” system, i.e., the pressure in the system is at least close to the ambient pressure according to one configuration. According to one additional development, the pressure also lies far below the ambient pressure. The pressure preferably is chosen such that vapor bubbles develop in the fuel. These vapor bubbles can damp waves. This furthermore makes it possible to homogenize a fuel flow. [0022] The invention also proposes a fuel injection device according to an accumulator principle, particularly according to the common rail principle, for a reciprocating internal combustion engine which features an injection nozzle and an injector part, wherein the injector part has a pressure chamber in which a closing element for closing the injection nozzle is guided, wherein the pressure chamber is connected via a connecting channel to a pressure booster that is arranged downstream of an accumulator, particularly a common rail, and upstream of the pressure chamber, and wherein the pressure chamber is connected to a low-pressure chamber via a pressure relief connection. [0023] According to one additional development, the control elements that are arranged downstream of the accumulator and serve to control the fuel flow are, with the exception of a control valve, controlled hydraulically by the control valve. [0024] According to another configuration, the pressure booster features a piston with a primary side and a secondary side, wherein the secondary side is connected to the pressure chamber via the connecting channel and to a control element arranged upstream of the low-pressure chamber via the pressure relief line. Such an arrangement makes it possible to achieve a very precise injection profile. It allows a direct shaping of an injection profile, wherein idle times, wave processes, inert masses and other interfering factors are prevented. [0025] A device of this type is particularly advantageous if injection pressures in excess of 2000 bar are achieved. For example, if injection pressures between 2500 bar and approximately 3000 bar are realized, the seals are subjected to particularly high stresses. A permanent stress on all components, particularly on at least the seals, is prevented due to the pressures made possible by the pressure booster, as well as the option of relieving the fuel pressure on the secondary side. This in turn makes it possible to extend the service life of this fuel injection device and to prevent leaks. [0026] According to one additional development, an evacuation chamber for the injection nozzle features a connecting line to a throttle that is arranged upstream of a low-pressure chamber. The throttle can have the function of suppressing oscillations in the evacuation chamber and in the lines that are connected to the evacuation chamber. However, the throttle can also damp a pressure wave, and in particular, cause a pressure build-up. This is preferably utilized for achieving a faster control of the injection valve. [0027] It would also be conceivable for the pressure relief connection between the pressure chamber and the low-pressure chamber to run via the evacuation chamber for the injection nozzle. This makes it possible to realize a pressure drop on the secondary side. The secondary side can be simultaneously utilized to control the injection valve. This in turn makes it possible to shorten the control time for the fuel injection device and therefore to improve the accuracy with respect to the volume to be injected as well as the injection sequence of this volume. An injection profile comprises, for example, a pre-Injection and/or post-injection that can be precisely metered with this fuel injection device. [0028] According to another configuration, an adjusting device is provided for raising and lowering an accumulator pressure, preferably a common rail pressure, in dependence on the load status of the reciprocating internal combustion engine. This makes it possible, for example, to realize the injection nozzle with smaller bores, particularly during the partial load operation. Smaller bores can have diameters, in particular, of 0.09 mm or less. Based on a displacement of 0.5 L per cylinder or more, the bore has a diameter of 0.15 mm or less. According to one configuration, the pressure in the common rail system is reduced during partial load operation of the reciprocating internal combustion engine. However, the pressure booster is able to generate a pressure on the secondary side that makes available a sufficient quantity to be injected despite the smaller bore sizes. An improved atomization of the injected fuel is achieved in this fashion. According to another configuration, the pressure in the common rail system is increased again during full load operation, for example, in a range between 80% and 100% of the output of the reciprocating internal combustion engine. The pressure upstream of the pressure booster can then be controlled such that it makes available, for example, an injection pressure that is adapted to partial load operation. However, it can also be realized such that an even higher pressure, and therefore greater volume, is made available for the injection. [0029] The pressure booster is preferably controlled hydraulically. This eliminates another adjusting element that needs to be actuated electromechanically or electrically and controlled in dependence on the control element. According to another configuration, an adjusting element, particularly a hydraulically controlled valve, is intermediately arranged between the low-pressure chamber and the pressure chamber and creates a connection with the evacuation chamber. This makes it possible for the pressure chamber to decrease or increase its pressure depending on the position of the controlled valve. If the valve is closed, the pressure in the pressure chamber is increased by the pressure booster if the primary side is acted upon with an appropriate pressure. If the valve is opened, fuel can flow from the pressure chamber into the evacuation chamber via the valve and from the evacuation chamber to the low-pressure chamber. This results in a pressure decrease in die pressure chamber that advantageously affects at least the closing of the injection nozzle. [0030] The injection nozzle used can consist of a hole-type nozzle. The nozzle can have a variable cross section. The nozzle can also feature, in particular, one or more rows of holes that are respectively opened or closed at different times or during different strokes of the closing element. According to one configuration, a nozzle is used in which needles with different cross sections are nested into one another. These movable needles can close and open different nozzle openings in different positions. According to another configuration, other nozzle geometries such as, for example, slots or the like, are provided. [0031] The fuel injection device is not only suitable for passenger cars, but also for utility vehicles including locomotives and ships or stationary motors. In particular, with respect to a hydraulic control it is advantageous for the lines and line cross sections used to be adapted to the respective motor. For this purpose, preferred line cross sections and valve cross sections with which, for example, the hydraulic control can be performed. According to one configuration, the pressure booster has a diameter between 4 mm and 6.5 mm on the secondary side. In contrast, the pressure booster has a diameter on the primary side that preferably lies between 7 mm and 11 mm. According to one configuration, the pressure booster is realized in the form of a piston with a stroke between 4 mm and 10 mm, preferably between 4 mm and 7 mm. The line diameter used depends once again on whether a high throughput must be ensured. If this is the case, it is preferred to use a line diameter of no less than 3 mm, wherein the diameter may, however, also become narrower over the length of the line. A certain minimum diameter may be required in other line regions. This minimum diameter is, for example, at 1.5 mm, particularly at least 2 mm. For example, the line leading to the pressure chamber preferably has a line cross section, for example, of at least 1.5 mm. An outgoing line of the accumulator, preferably the common rail, once again has a line cross section of no less than 3 mm, particularly when it is used in a passenger car. BRIEF DESCRIPTION OF THE DRAWINGS [0032] Other advantageous configurations are described with reference to the following additional developments. However, the respective characteristics are not limited to these particular additional developments. On the contrary, these characteristics may also form other configurations, particularly in connection with the characteristics described above. The figures show: [0033] FIG. 1 , a first fuel injection device; [0034] FIG. 2 , a second fuel injection device; [0035] FIG. 3 , a third fuel injection device; [0036] FIG. 4 , an example of an injection sequence for an operating point with the progression of various parameters over the course of an injection phase; [0037] FIG. 5 , an configuration example of a fuel injector, and [0038] FIG. 6 , an enlarged detail of a control element according to FIG. 5 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0039] FIG. 1 shows a first fuel injection device 1 . The first fuel injection device 1 features an accumulator 2 that supplies one or more injection nozzles 3 with fuel. The accumulator 2 features an adjusting device 4 that serves to raise and lower the pressure in the accumulator 2 . The adjusting device is preferably connected to a not-shown engine control that delivers signals in dependence on the load status of an internal combustion engine and therefore the required pressure in the accumulator 2 . One or more components of the fuel injection device 1 can also be directly or indirectly connected to the engine control, for example, via one or more control devices. However, the required sensors and signaling lines are not illustrated in the figure. [0040] The fuel is conveyed under pressure from the accumulator 2 to a first control element 5 and a second control element 6 . The function of the first control element is described, for example, in WO 01/53688, to which this application refers in this respect. The first control element 5 forwards the fuel to the second control elements 6 . This is realized by controlling the first control element 5 accordingly. For this purpose, the first control element 5 is equipped, for example, with an actuator 7 that is controlled by a control device or the engine control. Depending on the control of the actuator 7 , a fuel line 8 is unblocked by means of a first piston 9 that is illustrated in an enlarged fashion. A throttle 10 . 1 , 10 . 2 is preferably arranged upstream of at least the first control element 5 and/or the second control element 6 . The throttle damps possible oscillations in the lines that may be caused, for example, by adjustments of the first control element 5 or second control element 6 . In addition, the throttles 10 . 1 , 10 . 2 can generate a backpressure such that, for example, the pressure of the second control element 6 can be relieved and its position can be influenced. The throttles 10 . 1 , 10 . 2 assist in preventing the formation of bubbles and cavitation damage. It has furthermore proved advantageous to arrange a smoothing or compensating volume 11 upstream of the first control element 5 in order to damp possible pressure changes or oscillations. [0041] The function of the second control element 6 is also described, for example, in WO 01/53688, to which this application refers in this respect, wherein this second control element controls a pressure that acts upon a primary side 12 of a pressure booster 13 . The pressure booster 13 preferably features a reciprocating piston that is supported, for example, by means of springs. The pressure booster 13 features a primary side 12 that has a larger cross-sectional surface area than a secondary side 14 situated opposite from the primary side 12 . Fuel is conveyed from the secondary side 14 to a pressure chamber 15 of the injection nozzle 3 . The fuel can be injected into a not-shown cylinder from the injection nozzle 3 via the pressure chamber 15 . In addition to the connecting channel 16 , a pressure relief connection 17 is also connected to the secondary side 14 of the pressure booster 13 , wherein said pressure relief connection leads to an evacuation chamber 18 and from the evacuation chamber to a low-pressure chamber 19 . Via pressure relief connection 17 , the fuel originating from the secondary side 14 preferably first enters a third control element 20 that is controlled hydraulically and releases the connection to the low-pressure chamber 19 . [0042] The third control element 20 preferably serves as a pressure relief valve. In this case, the third control element 20 is designed, for example, such that the ratio between a surface 22 of the third control element 20 which is subjected to pressure and an end face of a control piston 23 approximately corresponds to the reciprocal value of the pressure increase realized with the pressure booster 13 , and therefore the ratio of the secondary side to the primary side. Consequently, a pressure in a control line 21 corresponds to the pressure on the primary side 12 of the pressure booster 13 . This means that the third control element 20 only opens, in particular, at the end of a fuel injection into the cylinder chamber. The fluid volume being injected within a very short period of time can be used subject the closing element 27 to additional pressure, particularly a pressure pulse, and thus closing this element more rapidly. The throttle 10 . 3 between the evacuation chamber 18 and the low-pressure chamber 19 serves to improve this pressure effect. After an injection process, the pressure booster 13 is returned into its starting position by a spring 24 , with the connecting channel 16 being filled with fuel by means of a check valve 25 . The springs arranged in the individual adjusting elements such as the valves, as well as the effective surface areas, are adapted to one another in such a way that control of the first control element 5 makes it possible to realize a fuel injection process with only the combined effect of compressive forces hydraulically transmitted to the individual components. [0043] FIG. 2 shows a second fuel injection device 28 that consists of essentially the same components as the first fuel injection device system 1 according to FIG. 1 , with these components fulfilling the same functions as in the first configuration. In this respect, identical reference symbols have been used. The second fuel injection device 28 represents another configuration, in which the second control element 6 is provided with a valve body 29 that is realized such that pressure originating from the primary side 12 of the pressure booster 13 at least exerts approximately no force upon the valve body 29 . Instead, an additional compensating force is exerted that is preferably generated by means of a compensation piston 30 in the configuration shown. A control side 31 of the compensation piston 30 is connected to the connecting channel 16 that serves as an injection line. This results in a force acting upon the valve body 29 in the closing direction. The ratio between the control surfaces of the valve body 29 and of the compensation piston 30 preferably corresponds to the ratio of the pressure increase of the pressure booster 13 . One advantage of this configuration can be seen in that an injection pressure is utilized to cause a reaction of the second control element 6 that serves as the control body, rather than a pressure from the primary side of the pressure booster 13 as is the case in the configuration according to FIG. 1 . In comparison with FIG. 1 , this makes it possible to additionally increase the metering accuracy of the injection realized by means of the injection nozzle 3 . In addition to the throttles shown in the figure, other throttles can be provided to suppress possible oscillations in the system according to FIG. 2 . [0044] FIG. 3 shows a third fuel injection device 32 . In this configuration, the pressure on the primary side 12 of the pressure booster 13 is relieved by means of the third control element 20 . This configuration can be utilized in a particularly advantageous fashion if larger quantities of fuel need to be added in a metered fashion. [0045] The fuel injection devices shown in FIGS. 1-3 can be assembled, in particular, in the form of a single module installed on the cylinder of an internal combustion engine. In this respect, the present application refers to WO 01/53688, in which such a basic design is described in detail. A fuel injection device of this type that is assembled in the form of a single module is also illustrated in FIG. 5 . It would also be conceivable for the fuel injection device to feature components that are arranged separately of one another. Another particularly preferred application of the fuel injection device is for test stands used to carry out basic research with injection pressures of at least 2000 bar, particularly in excess of 2500 bar. [0046] FIG. 4 shows an example of an injection sequence for an operating point with the progression of various parameters over the course of an injection phase. According to this figure, the fuel injection device makes it possible to realize a specific profile of the injection volume as a function of time by controlling the first control element only. The same injection phase time interval is illustrated on the X-axis for all parameters shown. The first control element that consists, for example, of a piezo-controlled actuator is operated by changing the applied voltage. The voltage is indicated in volts. Depending on this voltage, the valve of the first control element opens as indicated in μm. Since the components to be subsequently actuated react hydraulically and therefore without delay, the needle of the injection valve is raised almost simultaneously, with the pressure increase. Since the pressure on the needle seat is already increased before the needle valve initially opens, a directly metered quantity of fuel can be supplied into the combustion chamber or the channel when the valve opens. This means that less than 0.8 ms elapse between a voltage change on the actuator and the beginning of the injection. This rapid and immediate action also makes it possible to adjust the injection pressure by purposefully raising and lowering of the valve of the first control element. If the voltage is lowered again, the pressure is also lowered almost immediately, and the pressure change causes the needle stroke to change within a time interval of less than 0.7 ms. [0047] FIG. 5 shows an configuration example of a fuel injector, and FIG. 6 shows an enlarged detail of the first control element according to FIG. 5 . With the exception of the accumulator 2 , the adjusting device 4 and the low-pressure chamber 19 , the fuel injector features the components illustrated in FIG. 1 that are accommodated in a single module. For this purpose, the individual components feature pre-fabricated channels such that only a few processing steps need to be performed on the fuel injector when the individual components are assembled and joined. A very compact fuel injector can be realized due to the accommodation of all individual components in a single module.	A fuel injection method according to the invention that utilizes an accumulator principle, particularly a common rail principle, is characterized in that fuel arriving from an accumulator, particularly a common rail, is conveyed to a primary side of the pressure booster at a first pressure such that a secondary side of the pressure booster is subjected to a pressure increase, and in that an opening and closing of an injection nozzle are realized with the pressure in a pressure chamber for the injection nozzle, by displacing a closing element that acts upon the injection nozzle, particularly an injector needle, by means of a hydraulically controlled pressure change.	5
BACKGROUND In the sport of skeet shooting, automatic and semiautomatic machines have been developed for throwing or launching frangible clay targets into the air for a shooter. These targets have been called “clay pigeons” and typically are in the form of circular, disc-like members having a slightly hollowed-out underside. When these frangible clay targets are launched, they are thrown and simultaneously spun; so that they sail through the air after launching. Various types of machines have been developed in the past for launching single targets. Some of these machines place the target on a flat launching plate from which it is swept by a launching arm, which rapidly spins in a circular motion to sweep the target off the launching plate and launch it from the plate and the tip of the arm, as the arm completes a 360° revolution. Other devices place the target on a horizontal portion of a launching arm which has a vertical edge resting against the edge of the target. The arm carrying the target then is rapidly spun or snapped in a circular direction to launch the target, much in the same manner as targets are launched from the launching plate described above. As the sport of skeet shooting or trap shooting has evolved, a demand has arisen for simultaneously or nearly simultaneously launching two targets at different angles from essentially the same position. A very complex mechanism for achieving this is disclosed in the United Kingdom patent specification No. 2,189,154. The device of this specification employs two separate throwing arms, loaded from two separate magazines, for accomplishing the simultaneous throwing of two targets. The throwing arms are essentially independent of one another; so that the targets may be released at various angles, depending upon the orientation of each of the arms with respect to one another. The device of this patent, however, basically is a combination of two single-arm throwing devices in a generally unitary housing. No throwing of more than one target from a single arm is disclosed in this patent. Two United States patents, Heffer U.S. Pat. No. 5,036,828 and Cote U.S. Pat. No. 4,706,641, disclose devices for simultaneously throwing two targets with a single throwing arm. In both of these patents, the targets are dropped onto a horizontal portion of the throwing arm, and rest against a vertical portion. The entire arm, the part on which the bottom of the targets rest, as well as the part which pushes the targets away, is rotated to launch the targets. There is no separate fixed launch plate on which the targets are placed. As a consequence, the throwing arm has a relatively large amount of inertia because of the weight of the horizontal portion on which the targets are placed, since that portion, as well as the vertical edge which contacts the edges of the targets, all must be rotated along with the targets, to launch or release the targets. The United States patent to Patenaude U.S. Pat. No. 5,249,563 is directed to an apparatus for simultaneously, or nearly simultaneously, throwing two clay targets (or, optionally, a single target) using a single throwing arm. The device of the Patenaude patent uses a flat launching plate of the type discussed above,. which long has been used for launching or throwing single targets. In the Patenaude device, the target holding carousel is designed to release two targets in front of the launching arm, which then is moved to its cocked or launching position with a vertical edge resting against the edges of the targets, which are located side-by-side in front of the arm. Upon release, the arm rapidly rotates and launches and spins both of the targets outwardly with a single pass of the arm. After launching, the arm is re-cocked; and new targets are inserted into place for a subsequent launch. In conjunction with the prior art patents discussed above, and in fact with any device operating in the general manner described above for launching two targets, when the arm rotates (typically, in a counterclockwise direction), the targets both spin in a clockwise direction, and rotate down or along the length of the arm from its center location at the pivot toward its unsecured end. The targets then are launched at slightly different times. The target which is located nearest the end of the arm initially leaves first; and then the target initially located nearest the pivot arm leaves shortly after the first target. The first target to leave the throwing arm typically travels about 22° off of a line which is located 180° from the line of the start of the launch. The second target then travels about 22° after that same line; so that there is an angle of 44° between the targets. This is the norm or convention for all traps or launchers which release two targets from a single arm. The angle is simply determined by the physics of the system, which includes the diameter of the clay targets (which is standard). Accordingly, it is desirable to provide a skeet or trap launching machine in which the launching arm is adjustable to cause the angle between the released targets to be varied in a simple and effective manner. SUMMARY OF THE INVENTION It is an object of this invention to provide an improved throwing arm for a clay target launching machine. It is another object of this invention to provide an improved throwing arm for simultaneously throwing two targets from a clay target launching machine. It is an additional object of this invention to provide an improved throwing arm for simultaneously throwing two targets from a clay target launching machine which is capable of adjusting the angle between the launched targets. It is a further object of this invention to provide a throwing arm for a clay target launching machine which has an angularly adjustable target-engaging edge for varying the launch angle between two targets simultaneously launched by the machine. In accordance with a preferred embodiment of the invention, a variable angle throwing arm for a clay target launching machine comprises a main body portion which is rotated about a pivot for simultaneously launching pairs of targets. The main body portion has an elongated blade member attached to it, with a target-engaging edge on the blade member for engaging targets to be launched by the machine. The elongated blade member is adjustably secured by adjustment members to the main body member, to cause the target-engaging edge of the blade member to be oriented at different angles to effect different separation angles between the launched targets. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top front perspective view of a preferred embodiment of the invention; FIG. 2 is a detailed top rear perspective view of a portion of the embodiment shown in FIG. 1; FIG. 3 is a top view of the embodiment shown in FIG. 1 illustrating details of its operation; FIG. 4 is a top view of the portion shown in FIG. 2; FIG. 5 is a side view of the portion shown in FIG. 4; FIG. 6 is a cross-sectional view taken along the line 6 — 6 of FIG. 4; and FIG. 7 is an enlarged top front perspective view illustrating a detail of the embodiment shown in FIG. 1 . DETAILED DESCRIPTION Reference now should be made to the drawings, in which the same reference numbers are used throughout the different figures to designate the same components. All of the figures are directed to a preferred embodiment of the invention, which is a throwing arm for frangible clay targets sometimes known as clay pigeons. The throwing arm is designed for use in target launching machines, which may be of any of a variety of commercially available configurations. For this reason, details of the machine mechanism for rotating, releasing and cocking the arm, as well as for placing targets in front of the arm prior to release, are not illustrated in the drawing. The details of such machines are well known, and are not important for an understanding of the invention. Only those portions of target launching machines or trap machines which are required for an understanding of the preferred embodiment of the invention have been illustrated in the drawings. FIG. 1 is a top front perspective view of a preferred embodiment of the invention shown attached to portions of a clay target launching machine. Ideally, the launching machine with which the launching arm of the preferred embodiment of the invention is used employs a flat, steel launching plate 10 , on which the targets are placed, and from which they are pushed and launched into the air by the launching arm. Machines of this type have been available for many years, particularly for the launching of single clay targets. The mechanism for placing targets in a launching position, as well as for rotating and cocking the launching arm are well known and standard. In the device which is shown in the drawings, the launching arm comprises a main body portion, in the form of an elongated throwing arm 14 , which is attached by means of suitable fasteners 16 to a rotating circular pivot member 12 fastened for rotation on the plate 10 , through a central pivot 13 . This is shown most clearly in FIGS. 1 and 3. The arrows in both FIGS. 1 and 3 indicate the counterclockwise direction of rotation of the arm 14 during its operation. The arm 14 makes a complete 360° revolution for each cycle of operation, rapidly spinning under the force of a cocked spring (the details of which are not shown, since they are standard configurations) from the cocked or start position shown in both FIGS. 1 and 3, through a full circle, back to the cocked or start position ready for release of a new cycle. The cycling may take place automatically or semiautomatically, depending upon the machine with which the embodiment of the invention is used. In accordance with a preferred embodiment of the invention, the leading edge (the right-hand edge as shown in FIGS. 1 and 3) of the main body portion 14 of the throwing arm has an elongated blade 16 attached to it. As illustrated, the blade member 16 is provided with a plurality of elongated arcuate slots 20 (shown most clearly in FIGS. 2 and 4) and is pivotally attached to the underside, or to an intermediate slot in, the arm 14 , through a pivot 18 at the distal end of the arm 14 opposite the pivot 13 described above. This, again, is shown most clearly in FIGS. 1 and 3. Each of the slots 20 is aligned with a fastener 22 located along the leading edge of the throwing arm 14 to permit relative angular pivotal movement of the elongated blade 16 in the direction of the arrows shown in FIG. 1, back and forth from a position where the blade 16 parallels the leading edge of the arm 14 to a fully extended angular position, as illustrated in FIGS. 1 and 3. Once the desired angular position of the blade 16 has been established, the fasteners 22 are tightened to secure the blade in place on the arm 14 . It is readily apparent from an examination, particularly of FIG. 3, that the orientation of the leading or target-engaging edge (the right-hand edge) of the elongated blade member 16 creates an adjustment of the throwing position of the arm as it is rotated counterclockwise to release targets, such as the targets 40 and 50 shown in FIG. 3, from the target launching machine or trap machine. The leading or target-engaging edge of the blade 16 is provided with a pair of adjacent sleeves 26 and 24 . The sleeve 24 is approximately twice as long as the sleeve 26 . The material of the sleeve 24 is chosen to be a relatively high friction material, such as rubber or the like. The sleeve 26 , on the other hand, is made of relatively low friction material, such as nylon; so that as the targets 40 and 50 move along the sleeve, they are in contact with one or the other of these materials, which are used to impart spin to the targets and assist in launching them from the launching plate 10 . The entire front edge of the blade 16 could be covered with the same material, such as the material 24 , to impart spin to the edges of the clay target discs 40 and 50 , as is done in conjunction with conventional arms not having an adjustable blade. It should be noted that in conventional arms, where the launch is essentially effected from the leading or right-hand edge of for example the arm 14 , targets are launched at an angle which is approximately 44° between them. This is due to the physics of such machines, and is relatively consistent in conjunction with a variety of different launching arm configurations, as discussed above in the background portion. By allowing adjustability in any increment between parallel to the leading edge of the arm 14 to the extended position shown in FIGS. 1 and 3, the launching angle of the targets 40 and 50 , relative to the radial direction of the spin of the arm 14 around the pivot 13 , can be adjusted. This in turn allows the release angle of the targets 40 and 50 to be varied over a relatively wide range. This range is about 38° to 50°, using the configurations which are shown in the drawings. By employing a very low friction surface 26 on the portion of the blade 16 located nearest the pivot 13 , and a higher friction surface (such as a rubber surface) on the target contacting edge 24 of the blade 16 , an even greater range of dispersal of the targets, particularly providing lower degrees of separation, can be provided. As shown in FIG. 3, when two targets 40 and 50 are placed in the launching position, the innermost target 40 has its edge resting against the low friction portion 26 on the leading edge of the blade 16 . At the same time, the target 50 has its edge resting on the higher friction surface 24 on the leading edge of the blade 16 . When launch is effected, the target 50 rolls along the higher friction edge 24 , which imparts spin to it immediately. The centrifugal force of the apparatus causes the target 40 to slide in the direction of the left-hand arrow shown in FIG. 7, along the surface 26 , picking up some spin but not as much as it encounters when it reaches the section 24 during subsequent portions of the rotation of the throwing arm 14 when the targets 40 and 50 are being launched. Without this smooth surface of the section 26 , the separation angle between the targets 40 and 50 is slightly greater than with this surface in place. Obviously, by varying the relative lengths of the sections 24 and 26 , the difference in the separation angle which is attainable with the system is varied accordingly. This variation is in addition to any variation which is effected by the angular positioning of the leading edge of the blade 16 relative to the edge of the throwing arm 14 . It also should be noted that, in the example which is illustrated throughout the different figures, the arm 14 is offset from the center line through the pivot 13 ; so that there is a “hook” type of action in the illustrated throwing arm. The utilization of the adjustable blade 16 , however, can be used in conjunction with straight throwing arms as well as the hook throwing arm shown. The variations in the angles between the targets 40 and 50 , as they are thrown for different adjustments of the blade 16 , are attainable with straight arms as well as with the hook arm shown in the various figures of the drawing. As illustrated in FIGS. 1 and 3, a stop 34 is pivotally secured through a pivot 35 , to a plate 30 in the launching machine. The stop 34 is used to keep the launching arm 14 in its cocked, ready-to-launch position until targets 40 and 50 are placed in front of the target-engaging edge of the blade 16 , as illustrated in FIG. 3 . The manner in which the targets are placed may be through any suitable apparatus. Slots 28 in the plate 10 are illustrated for accommodating a target lowering elevator, or the like. The manner in which targets 40 and 50 , however, are placed is irrelevant to the function of the throwing arm; and for that reason, such mechanism has not been disclosed. Once the targets 4 and 50 are in place, the latch 34 is momentarily pivoted on the pivot 35 in the aperture 32 to move it out of the way of the end of the blade 16 and throwing arm 14 . This allows the spring-loaded throwing arm to fling the targets 40 and 50 out of the machine. Once the arm has been released by the pivoting away of the stop 34 , it is returned to the position shown in FIGS. 1 and 3 by suitable mechanism (not shown) to ready the machine for the next launch cycle. Also shown in FIGS. 1 and 3 is a slightly raised circular section 11 , which underlies the arm 14 and blade 16 to provide a low friction surface for the arm 14 and blade 16 during the launch cycle. This raised portion allows the sliding contact of the arm 14 and/or blade 16 over the launching plate 10 to be reduced to a relatively small area; so that friction encountered by the arm 14 and/or blade 16 during the launch cycle is minimized. The foregoing description of the preferred embodiment of the invention is to be considered as illustrative and not as limiting. Various changes and modifications will occur to those skilled in the art to perform substantially the same function, in substantially the same way, to achieve substantially the same result, without departing from the true scope of the invention as defined in the appended claims.	The throwing arm for a clay target launching machine is designed with an adjustable leading edge or target-engaging edge of the throwing arm. This edge is separately, pivotally mounted on a main body member, which in turn is pivoted to launch the targets. By adjusting the angle of the leading edge of the throwing arm, causing it to be offset from a center line through the central pivot of the main body member of the throwing arm, the angle between two simultaneously released targets can be varied from an angle which is less than that of conventional devices to an angle which is greater than that of conventional devices. A further enhancement includes constructing the leading edge of the throwing arm with materials of different coefficients of friction to provide additional variations in the angle at which targets are released by the machine in which the throwing arm is used.	5
BACKGROUND The production of electrical energy from electrical energy from the surroundings without utilizing a utilization of a battery is a form of energy harvesting. Energy harvesting also known as power harvesting or energy scavenging is a process by which energy is captured and stored. Energy harvesting makes it possible to drive electrical systems without the necessity of battery or a more restrictive accumulator. Energy harvesting systems conventionally use thermal electricity or mechanical vibrations which are converted to electric energy. Some electrical generating systems make use of reciprocating magnet movement through one or more coils. The movement of a magnet through a conductive coil induces a current flow in the coil. The coupling of the mechanical energy through an inert mass is usually done by means of a mechanical feather or spring. If the magnet is moved back and forth in a reciprocating motion, the direction of current flow in the coil will be reversed for each successive traverse, yielding an AC current. Another form of energy harvesting systems is provided for harvesting energy from the environment or other remote surfaces and converting it electrical energy. This type of harvester relies on another source of the magnetic field or the earth's magnetic field that is external to the harvester. The harvester in this case does not contain a permanent magnetic or other local magnetic field source. Harvesters of this type may be smaller and lighter than an energy harvester that contains the magnet. Additionally, by having an external magnetic field they do not require vibrational energy. For these and other reasons, there is a need for the present invention. SUMMARY An energy harvesting system in accordance with disclosed embodiments includes a rotatable member with an electrically conductive coil mounted to the rotatable member and adapted to move with the rotatable member such that the movement of the coil through a magnetic field induces a voltage in the coil. An energy storage device is coupled to the coil. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification. The drawings illustrate the embodiments of the present invention and together with the description serve to explain the principles of the invention. Other embodiments of the present invention and many of the intended advantages of the present invention will be readily appreciated as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding similar parts. FIG. 1A is a block diagram conceptually illustrating an embodiment of an energy harvesting system. FIG. 1B is a block diagram conceptually illustrating an embodiment of an energy harvesting system. FIG. 1C is a block diagram conceptually illustrating an embodiment of an energy harvesting system. FIG. 2 is a block diagram conceptually illustrating aspects an embodiment of a tire system including an energy harvesting device. FIG. 3 is diagrammatic representation illustrating aspects an embodiment of a tire system including an energy harvesting device. FIG. 4 is a diagrammatic representation illustrating aspects an embodiment of a tire system including an energy harvesting device. DETAILED DESCRIPTION In the following Detailed Description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” “leading,” “trailing,” etc., is used with reference to the orientation of the Figure(s) being described. Because components of embodiments of the present invention can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims. FIGS. 1A-1C are block diagrams illustrating aspects of an energy harvesting system in accordance with embodiments of the invention. The system for which energy is supplied may be any device which requires energy and is subject to some degree of movement and rotation, for example, a tire sensor mounted inside a tire. The disclosed energy harvester may be applicable in situations where it is not easy to access other types of power, although its application can be anywhere energy harvesting is sought. The energy harvester provides for conversion of magnetic energy to electrical energy. FIG. 1A is a block diagram illustrating an implementation of an energy harvesting system 10 in accordance with embodiments of the invention. FIG. 1A illustrates a magnetic field 12 , such as the Earth's magnetic field, applied to an energy harvester 14 . Electrical energy generated by the energy harvester may be applied to an electronic device or system 16 to be powered and/or an energy storage device 18 . The energy harvester 14 provides electrical energy to the system 16 such as a tire pressure gauge mounted to a tire, for example. The energy storage device 18 stores the electrical energy generated by the energy harvester 14 . The energy storage device 14 may be a capacitor or battery, for example. The energy storage device 18 stores energy for future use by the system 16 . FIGS. 1B and 1C illustrate further embodiments. In FIG. 1B , the energy harvester 14 is connected to the energy storage device 18 , which supplies power to the system 16 . FIG. 1C illustrates a diagrammatic representation of an energy harvesting system according to another embodiment. An outside magnetic field source is applied to the energy harvester. Electrical energy generated is then sent to the system for use. FIG. 2 is a block diagram illustrating an energy harvesting system, similar to that illustrated in FIGS. 1A-1C , where the energy harvesting system is implemented with a tire. Many different types of wheeled vehicles use pneumatic tires (in this specification, the term tire generally refers to a pneumatic tire). Typically, a tire is mounted on the rim of a wheel, which is mounted to a vehicle. Sensor devices exist for providing information about the tires of a wheeled vehicle. Features such as automatic stability and traction control in cars have made it necessary to obtain information about the interaction between the tires and the road surface. Such information is available from several sources, including ABS sensors, tire pressure measurement systems, and accelerometers and gyros located in the vehicle. Such sensors require an energy source to power the device, which is typically a battery. Eliminating the battery as the energy source for tire-mounted sensors, or providing an energy source for charging the battery is desirable from cost, reliability and environmental standpoints. FIG. 2 conceptually illustrates the system 100 implemented with a tire 110 . The magnetic field 12 is applied to the tire system 110 inclusive of the energy harvester 14 . Energy generated by the tire's energy harvester 14 is supplied to an energy storage device 18 and/or the system 16 being powered, such as a tire sensor device. As illustrated in FIGS. 1A-1C , the harvested energy can be applied both the storage device 18 and powered system 16 , serially to the energy storage device 18 and then to the system 16 , or applied directly to the system 16 , for example. FIG. 3 illustrates further aspects of an embodiment of the system 100 . Energy harvester 14 includes an electrically conductive coil 114 situated inside the tire 110 . The coil 114 is connected to the system to be powered 16 (such as a tire sensor) and/or an energy storage device 18 as illustrated in FIGS. 1 and 2 . The tire 110 containing the electrically conductive coils 114 rotates as indicated by the arrow 120 . As the tire 110 rotates relative to the magnetic field source 12 , which is the earth's magnetic field or other suitable magnetic field source, the coil 114 cuts through the magnetic field 12 as the orientation of coil 114 changes from vertical to horizontal and horizontal to vertical, inducing an electrical current in the coil 114 . The magnetic flux Φ created as the tire rotates can be calculated by Φ=BA where B is the strength of the magnetic field 12 and A is the cross-sectional area defined by the coil 114 . As the tire 110 rotates, the cross-sectional area A as a function of time is A=nr o 2 cos φ=A o cos ωt where r o is the radius of the coil 114 (which is about equal to the cross-sectional radius of the tire 110 depending on the manner in which the coil 114 is mounted to the tire 110 ), φ is the change in angular position of the coil 114 , and ω is the angular velocity of the tire. The driving speed v of the tire 110 having a radius r is v=ωr and thus, the induced voltage V ind as a function of time is V ind = - n ⁢ ⁢ ⅆ / ⅆ t ⁢ ⁢ Φ = - n ⁢ ⁢ B ⁢ ⁢ ⅆ / ⅆ t ⁢ ⁢ A ⁡ ( t ) = nBA o ⁢ ⁢ v / r ⁢ ⁢ sin ⁡ ( tv / r ) where n is the number of turns in the coil 114 . For example, if the Earth's magnetic field is estimated at 30 μT and the following values are assumed: r o =0.1 m r=0.2 m v=60 km/h≈20 m/s n=100 turns a voltage having an amplitude of about 100 mV with a frequency of 100 Hz is induced. The energy generated in this manner is supplied to the energy storage device 18 and/or directly to the system 16 . The conductive coil 114 can be mounted on the inside surface of the tire 110 , or even embedded into the material of the tire 110 . In the embodiment illustrated in FIG. 3 , the coil 114 defines an axis that is generally parallel to a line tangent to the tire 110 —the coil 114 is generally coaxial with the cross-section of the tire 110 . The coil 114 includes a predetermined number of turns based on the particular device or system 16 to be powered. FIG. 4 is another embodiment of a tire system 100 including an energy harvesting device 14 , similar to FIG. 3 . In this embodiment, the energy harvester 14 includes an electrically conductive coil 214 with an axis 228 generally radial to an axis of rotation 218 of the tire 110 . The tire 110 , containing the coils 214 , rotates as indicated by the arrow 120 , relative to the magnetic force 12 . The induced voltage V ind is a function of time, as previously described and illustrate with reference to FIG. 3 . Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof.	An energy harvesting system and method includes a rotatable member with an electrically conductive coil mounted to the rotatable member and adapted to move with the rotatable member such that the movement of the coil through a magnetic field induces a voltage in the coil. An energy storage device is coupled to the coil.	5
CROSS-REFERENCE TO RELATED APPLICATIONS This application is a U.S. national phase application under U.S.C. §371 of International Application No. PCT/EP2013/069695 filed on Sep. 23, 2013 and claims benefit to European Patent Application No. EP 12191125.9 filed Nov. 2, 2012. The international application was published in English on May 8, 2014 as WO 2014/067711 A1 under PCT Article 21(2). FIELD OF THE INVENTION The invention relates to method or device for network controlled optimization of a hybrid access traffic management for a residential user connected via a hybrid access home gateway, which provides at least two different network links with different technology to a core network, wherein the core network has a connection to the internet, wherein in the core network a Hybrid Access Server is located, which has a connection to the to the hybrid access enabled home gateway, over the two or more network links. BACKGROUND OF INVENTION Internet-based services and applications are rapidly growing and are fundamental to fulfill people's needs in areas such as communication, banking, shopping, information, education and entertainment. High performance internet access solutions are an important prerequisite. Currently, in most cases residential customers use DSL technologies (such as ADSL or VDSL) for Internet access, whereas mobile customers use cellular technologies (such as GSM, UMTS or LTE). The maximum data rates which can be provided via DSL depend on the length of the access line. For longer distances, e.g. in rural areas, in many cases only a few Mbit/s are feasible. To mitigate limitations in the access, a bonding of multiple access links can be applied. Solutions are available in particular for business customers, e.g. bonding of multiple DSL lines [1]. It is also possible to combine access links provided by different media, such as DSL and cellular access, as for example described in [2]. This “hybrid access” is technically much more challenging than the combination of multiple links of the same media, in particular due to the high dynamics of the mobile access link (e.g. in terms of available throughput or latency) and due to the completely different access and core network architectures of existing fixed and mobile networks. A typical available solution for a “hybrid access” is sketched in FIG. 1 . It consists of multiple “hybrid access clients” (e.g. residential gateways or other devices such as desktop or laptop computers) controlled by a common “hybrid access server”. (For simplicity reasons in FIG. 1 only one client is depicted.) Each hybrid access client has at least two access interfaces, one for example for DSL access and another one for example for access to cellular networks (e.g. UMTS networks or LTE networks). The hybrid access server is located in the public Internet. It is the common anchor point which processes all data packets from/to the client when communicating with an applications host (e.g. a content server), e.g. located in the public Internet. The traffic between the hybrid access clients and the hybrid access server is controlled by distributed “hybrid access algorithms and protocols” which decide which part of the user traffic will be transmitted via which access medium. The traffic split can be done with different granularities, e.g. packet-wise splitting or distributing the different IP flows. In addition to the user traffic some control traffic generated by the hybrid access algorithms and protocols has to be transmitted via the different access channels. In many cases, tunnels between a hybrid access client and the hybrid access server are established over the different access channels (e.g. using OpenVPN), e.g. for security reasons. More sophisticated solutions try to perform measurements of instantaneous channel parameters (see e.g. [4]) of the different access links and use these parameters as input for algorithms controlling the traffic flows. However, the measurements often show a low accuracy and produce additional traffic overhead. The general drawback of the current hybrid access solutions, including solutions working above IP layer (e.g. “Multipath TCP” [3]) is that they work “over the top”, that means the networks between the hybrid access client and the hybrid access server are used as unknown “clouds”. Knowledge available in the access and core networks (e.g. network load, available capacity, requested or used services . . . ) is not utilized for the algorithms controlling the hybrid access. Moreover, if tunnels are used via the different links between hybrid access client and hybrid access server, it may not be possible to reach service control platforms located in the operator's core network, e.g. an IMS platform to control a “Voice over IP (VoIP)” service. SUMMARY OF INVENTION The invention comprises a method for network controlled optimization of the hybrid access traffic management for a residential user connected via a hybrid access home gateway, which provides at least two different network links with different technology to a core network, wherein the core network has a connection to the internet, wherein in the core network a Hybrid Access Server is located, which has a connection to the to the hybrid access enabled home gateway, over the two network links, wherein by using information available from the fixed and mobile access and aggregation networks the method comprises the steps: extracting by the Hybrid Access Server one or more of the following information: Network link availability, Network link utilization, Quality of Service information with respect to the services requested from the home gateway, Short-term and long-term prediction of available capacity on selected network segments, progress information on performing transport tasks (e.g. based on buffer fill level at the interfaces of network nodes) control of the following processes by the Hybrid Access Server in communication with the hybrid access home gateway and/or other components in the network based on the extracted information: activation and selection of networks links, selection of the network traffic routing, IP packet or higher layer data segment distribution to the different links and/or selection of the service routing including dynamic session or service or service category assignment to the different links. Optional it is possible to adapt the transport network characteristics or content quality: adaption of scheduling and prioritization in selected network segments, implementation of fairness or policies over the entire hybrid link, equalization of link parameters and limitation of link parameter differences by the network to achieve a more homogeneous appearance to higher network layers, adaption of content quality to the performance of the hybrid link. In a preferred embodiment the one network link is established via a mobile network and the other via a cable connection, preferably DSL. The mobile network is preferably a GSM, GPRS, EDGE, UMTS, LTE, CDMA etc network. To optimize the connection the cell of the mobile network link can be selected if several cells are accessible. The selection is done based on the instantaneous and/or average load of the mobile cells, to provide a maximum data rate and/or minimum response delay, wherein the selection can take into account different times of a day. In a possible approach the cell selection can be done based on a long term prediction of the daily load in the cells. This allows a daily selection principle. In reaction to very high loads or a strong demand of bandwidth the cells can also be changed in a very short reaction time. In another embodiment the Hybrid Access Server is in communication with the hybrid access home gateway to define routes for different services provided to the end user over different links, to ensure quality demands of the services. By this approach, for example Internet communication can be performed over the wireless link, wherein streaming of video or audio can be performed over the DSL-connection. The Hybrid Access Server gets the information from different network components, within the fixed or mobile access networks, or the fixed or mobile core networks. The different types of services requested by an end user can be determined by the hybrid access home gateway on the basis of IP-address, protocol, sockets etc. Also the Hybrid Access Server gets its information by being connected with the mobile and fixed network components to retrieve information about the network status: For the aggregation and core networks all involved components (especially routers, switches and similar equipment) should report about their current load situation and the current utilization of the used links. The mentioned components can be: For LTE networks: Serving Gateway (S-GW), Packet Gateway (P-GW) For DSL networks: Broadband Remote Access Router (BBRAR) For UMTS and GSM networks: The Serving GPRS Support Node (SGSN) and Gateway GPRS Support Node (GGSN) All other kinds of switches and routers For access networks: In case of a shared medium (e.g. wireless networks, cable TV networks): The controller of the shared medium should be report about the current load of the shared medium and about the link conditions (e.g. modulation and coding scheme) to the hybrid access clients. The controller can be: enhanced NodeB in case of LTE Base Station Controller (BSC) in case of GSM Radio Network Controller (RNC) in case of UMTS Cable Modem Termination System (CMTS) in case of a cable TV network In case of non shared medium (e.g. DSL networks) the controller of the access link should report about the current link condition to the hybrid access clients. The controller can be: Digital Subscriber Line Access Multiplexer (DSLAM) in case of DSL Regarding mobile networks the requested parameters for new Operation and Management Systems are described by the following requirement specification of NGMN Alliance (R19/page 24): http://www.ngmn.org/uploads/media/NGMN_Recommendation_on_SON_and_O_M_Requir ements.pdf Therefore it can be expected that in near future nearly all of these parameters can be used for hybrid access in the context of the solution described herein. Also the Hybrid Access Server can be in connection to the components of the core network to retrieve information of the services used by the hybrid access home gateway and/or the QoS (Quality of Services) Classes assigned to the services. This information is typically available from IMS (IP Multimedia Subsystem) or SIP (Session Initiation Protocol) entities. In terms of IMS these are Resource and Admission Control Function (RACF) and Call Session Control Function (CSCF). Related to SIP these are Application Layer Gateway and SIP Proxy Server. The Hybrid Access Server calculates a long term prediction of parameters of the access channels and/or short term corrective update. The long term prediction uses information collected over several months to predict the daily network demands of the end users. Furthermore the load of the network components of the core, access and mobile network can be monitored and be used to setup the connection and the selection of the cells of the hybrid access home gateway. For example the bandwidth or the load is estimated by using performance test regularly and/or by requesting information from a mobile base station. On the basis of this information the link in the mobile network can be changed by forcing a handover between cells, which is performed on basis of an instruction of the Hybrid Access Server to establish a load balancing with respect to different cells. The hybrid access home gateway has in general several network connections to the home network, via Ethernet or WLAN to connect local units. When an end user requests with a connected end user device for a different and/or additional service the Hybrid Access Server will be informed by the components in the network and can change the downlink routing as well as trigger the hybrid access home gateway to change the uplink routing over the network links specifically for the services. Also this information can be provided by the hybrid access home gateway to the Hybrid Access Server. The connection between the units can use a defined service protocol which allows an exchange of information and which allows a setup of the hybrid access home gateway, especially to setup the routing. Another aspect of the invention is a system comprising of a Hybrid Access Server and a hybrid access home gateway configured to implement the method according to the claims. The units have the network interfaces described above and implement the process described. The performance, the efficiency and flexibility of hybrid access solutions can be significantly improved if information available in the access and core networks is used to optimize the hybrid access traffic control mechanisms. Information extracted out of different parts of the networks can be out of the following categories: Resource availability and resource utilization as well as QoS (Quality of Service) information in the access and aggregation networks Information about service requests, service utilization and related QoS information available in the core networks By providing the hybrid access algorithms with this kind of information and by integrating the hybrid access server in the core network of a network operator the following advantages can be achieved: Provide all users (fixed access users, hybrid access users and mobile users) with optimal quality and performance by an overarching traffic management, including an overarching QoS control and prioritization Optimized utilization of all available resources in the networks. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 shows the component of the Hybrid access network; FIG. 2 shows an implementation of the Method according to the invention based on FIG. 1 DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS One example for the invention is a network controlled optimization of the hybrid access traffic management for a residential user connected via a hybrid access enabled home gateway by using the following information available from the fixed and mobile access and aggregation networks: From the fixed access network: Information about the DSL bit rate available for a certain residential user. From the mobile access network: Information about the instantaneous and average load of the mobile cells (including average load over day time) suited to cover the hybrid access enabled home gateway and about the maximum data rate possible to the dedicated residential user (depending or radio propagation conditions) Based on this information, the hybrid access algorithm can perform the following functionality (among others): 1. Setting of optimum average distributions of traffic between the different access channels. The setting may change over day time taking into account that the load in the mobile network may be different for different times of the day. Based on known load distributions over the day also a prediction of the available capacity in the future is possible. 2. Decision to which mobile radio cell the hybrid access client will be connected: If the hybrid access client may be able to establish connections to different radio cells in the surrounding area, the cell with the lowest load shall be selected, although this cell may not provide the best radio coverage (i.e. load balancing between neighboring radio cells). These functions are possible by incorporating information out of the networks. The overarching capacity and load management ensures for example, that there is no negative impact on the mobile users by hybrid access users. A second example is a service controlled steering of the hybrid access mechanism. If the user for example wants to initiate a voice call then the hybrid access server will be informed by the related core network components (e.g. IMS) and decides not to split the traffic but transporting it via a single access link, e.g. the DSL connection. But if during the voice call the user may decide to initiate a second service, e.g. a video streaming, which could be advantageously transported for example via the DSL link, then the algorithm may decide to switch the voice call to the cellular link if for example the DSL link may not be able to support the voice and video service simultaneously with sufficient quality. In FIG. 1 and 2 the basic principle of the invention are illustrated. In contrast to previous solutions, the hybrid access server is located in the core network of a network operator and has connections to the following network entities: 1. Connection to entities in the mobile access & aggregation network performing traffic control and resource management: At these entities information is available about the average load of the radio cells and in addition an instantaneous view on the requested resources by the users in the radio cells and resources still available in the radio cells (e.g. available in the scheduler at a mobile base station). Furthermore, the mobility management, including handovers between radio cells, is performed at these components. 2. Connection to mobile core components (incl. mobility management, service delivery & control, QoS control . . . ): At these components information about the services used by the mobile users in the radio cells, about the QoS classes assigned to dedicated services or to different users, etc. is available. The mobility management is controlled here. 3. Connection to fixed access & aggregation traffic control: At these entities (which can be e.g. the DSLAM) information about the maximum data rates available for the different DSL users is available 4. Connection to fixed core components (incl. service delivery & control, QoS control, resource and admission control . . . ): At these components information about the services used by the fixed access users, about the QoS classes assigned to dedicated services or to different users and available resources for additional services is available. For information exchange between the mentioned network entities and the hybrid access server protocols can be defined to standardize the information exchange. With this new architecture and new methods, the following unique hybrid access functionalities can be realized: 1. Optimized network resource utilization, including: a. Long term prediction of parameters of the access channels (e.g. average available bandwidth, latency . . . ), complemented by short term adaptations (in particular for the mobile access channel). The short term information can be derived by two different methods: i. Measurement of short term parameters by methods as for example described in [ 4 ]. The drawback is that extra signaling overhead is generated ii. Extracting the information about requested resources by the users in the radio cells and resources still available in the radio cells out of the scheduler at a mobile base station. The short term parameters of the access channels can be advantageously used in the hybrid access algorithm to optimize the assignment of traffic (e.g. packets or flows) to the different access channels. b. Load balancing between mobile radio cells: If the hybrid access client may be able to establish connections to different radio cells in the surrounding area, the cell with the lowest load shall be selected (although this cell may not provide the best radio coverage). Furthermore, a network initiated handover can be performed in order to achieve a better load distribution between the radio cells. To initiate the handover, the hybrid access server can have a connection with the mobility management function located in the mobile core network or the mobile access network. 2. Service dependent control of hybrid access, including: a. Determine and predict data rate requirements of used services: By communicating with core network components of the fixed and the mobile network the hybrid access functionality can identify the used services of the hybrid access clients. b. Hybrid access traffic management adapted to requirements of used service: Using the knowledge about the used services the hybrid access functionality can steer the traffic to the most suitable access channel, e.g. to use only DSL for voice services c. Adapt service quality to available network resources: For services with an adaptable service quality (e.g. video streams that can be delivered with different resolutions and bitrates) the hybrid access can in cooperation with other core network components adapt the service quality taking into account all existing access links to the hybrid access client. 3. -Overarching QoS control, including: a. prioritization of access channels depending on QoS requirements of used services and QoS agreements with users, respectively b. optimize resource assignment according to overall “cost” criteria (“cost” may be for example according to an optimized fulfillment of the QoS requirements of all mobile and hybrid access users, according to effort for the network operator to transmit data via a certain access channel, . . . ). This can be done on a basis per client (e.g. that first all available resources of a DSL access channel is used before additional resources from a cellular access channel are used). Additionally it possible to optimize the resource assignment for multiple hybrid access clients: As the hybrid access server can gather the information for several clients it can aim optimize the overall network usage of all hybrid access client, e.g. to provide a minimum data rate to all clients. 4. Optimization of (operator) network functionalities for hybrid access scenario. Regarding items 1.-3. Optimization is performed in the hybrid access home gateway and the hybrid access server based on information requested from the network. In further optimization steps some network functionalities can be adapted to the hybrid access scenario. a. Scheduler of the mobile base station. Currently there are different types of schedulers used to achieve a fair sharing of the base station resources. One type of scheduler distributes the resources based on equal time intervals (Round Robin). Another type of scheduler considers link quality to achieve a better fairness (Proportional fair). A new “hybrid access proportional fair scheduler” also has to take the link quality of the DSL link into account. b. Equalization of link parameter and limitation of link parameter differences in the transport network Hybrid access algorithm show very good performance if the bonded hybrid links have similar parameters e.g. regarding throughput and delay. Furthermore some higher network layers like TCP adapt permanently to these link parameters, which is more efficient if the hybrid link shows a nearly stationary behavior. Therefore, equalization of link parameter and limitation of link parameter differences can be an adequate mean to improve overall performance of the hybrid access. In “over the top” solutions hybrid access gateway and hybrid access server have only the possibility to delay or limit some traffic in one or other link which results in adjustment to the weakest link. Equalization in the transport network can additional use prioritization (e.g. in the MPLS transport network) and assignment of very high bandwidth in some network segments to compensate bottlenecks in other segments. This will result in better performance parameters of the hybrid access at expected lower cost for equalization due aggregation effects (e.g. hardware memory for data buffering is mainly unused if customer is offline). c. Transcoding Despite of using a hybrid access system by the customer some application e.g. video can show bad performance for some time. Often the perceptible quality can be improved (lower resolution is better than stuttering) if a transcoding is performed. The transcoding system and algorithm is now to be controlled by the hybrid access link quality. While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. It will be understood that changes and modifications may be made by those of ordinary skill within the scope of the following claims. In particular, the present invention covers further embodiments with any combination of features from different embodiments described above and below. Additionally, statements made herein characterizing the invention refer to an embodiment of the invention and not necessarily all embodiments. The terms used in the claims should be construed to have the broadest reasonable interpretation consistent with the foregoing description. For example, the use of the article “a” or “the” in introducing an element should not be interpreted as being exclusive of a plurality of elements. Likewise, the recitation of “or” should be interpreted as being inclusive, such that the recitation of “A or B” is not exclusive of “A and B,” unless it is clear from the context or the foregoing description that only one of A and B is intended. Further, the recitation of “at least one of A, B, and C” should be interpreted as one or more of a group of elements consisting of A, B, and C, and should not be interpreted as requiring at least one of each of the listed elements A, B, and C, regardless of whether A, B, and C are related as categories or otherwise. Moreover, the recitation of “A, B, and/or C” or “at least one of A, B, or C” should be interpreted as including any singular entity from the listed elements, e.g., A, any subset from the listed elements, e.g., A and B, or the entire list of elements A, B, and C. LITERATURE [1]ITU Recommendations G.998.2, Ethernet-based multi-pair bonding. [2]EP 2375797 A1: ADSL and 3G Traffic Aggregation in Home Gateway Environment. [3]IETF RFC 6182: Architectural Guidelines for Multipath TCP Development. [4]Ningning Hu, Peter Steenkiste: Estimating Available Bandwidth Using Packet Pair Probing, School of Computer Science, Carnegie Mellon University, Pittsburgh, September 2002. Acronyms BS Base Station CN Core Network DSLAM Digital Subscriber Line Access Multiplexer EPC Evolved Packet Core GGSN Gateway GPRS Support Node GSM Global System for Mobile Communications IMS IP Multimedia Subsystem LTE Long-Term Evolution MS Mobile Station P-GM Packet Gateway QoS Quality of Service RAN Radio Access Network UMTS Universal Mobile Telecommunication System VoIP Voice over IP	A method for network controlled optimization of hybrid access traffic management for a residential user connected via a hybrid access home gateway, which provides at least two different network links with different technology to a core network, wherein the core network has a connection to the internet, wherein in the core network a Hybrid Access Server is located, includes: extracting by the Hybrid Access Server one or more of the following information: Network link availability, Network link utilization, Quality of Service information with respect to the services requested from the home gateway; and selecting networks links, network traffic routing, and/or service routing by the Hybrid Access Server in communication with the hybrid access home gateway and/or other components in the network.	8
[0001] This application claims priority to U.S. Provisional Application Ser. No. 61/043,946, filed on Apr. 10, 2008, the entire contents of which are hereby incorporated by reference. [0002] The present invention application relates to protective garments, and more particularly, to protective garments configured to increase protection from harmful materials, such as noxious vapors. BACKGROUND [0003] Protective or hazardous duty garments are used in a variety of industries and settings to protect the wearer from hazardous conditions such as heat, fire, smoke, cold, sharp objects, chemicals, liquids, fumes and the like. Such protective or hazardous duty garments are often used in adverse conditions, such as in the presence of high temperatures, smoke, chemicals, vapors and the like. However, existing garments may not provide sufficient protection from harmful vapors. SUMMARY [0004] In one embodiment, the present invention is a garment having a skirt to protect the wearer from harmful vapors and/or other undesired materials. In particular, in one embodiment the invention is a coat including a torso portion defining a torso cavity and including pair of portions that are releasably connectable together. The coat further includes a skirt positioned in the torso cavity. The coat is configured such that when the coat is worn by a wearer and the portions are releasably connected together the skirt generally sealingly engages the wearer. The coat is further configured such that the skirt automatically generally sealingly engages the wearer when the coat is worn by the wearer and the portions are releasably connected without requiring any further action by the wearer. BRIEF DESCRIPTION OF THE DRAWINGS [0005] FIG. 1 is a front perspective view of one embodiment of the coat of the present invention, with certain layers cut away for illustrative purposes; [0006] FIG. 2 is a front view of the coat of FIG. 1 being worn and opened to expose the vapor skirt; [0007] FIG. 3 is a sectional view taken through the torso of the coat and wearer of FIG. 2 ; [0008] FIG. 4 is a side cross sectional view of part of the coat of FIG. 2 , illustrating one manner in which the vapor skirt may be attached to the coat; and [0009] FIG. 5 is a side cross sectional view of part of the coat of FIG. 2 , illustrating a differing thermal liner system than that used in FIG. 4 . DETAILED DESCRIPTION [0010] FIG. 1 illustrates a protective or hazardous duty garment in the form of a firefighter's coat, generally designated 10 . The coat 10 may include a body portion 12 having a left front panel or portion 14 , right front panel or portion 16 , and a back panel or portion 18 . The panels/portions 14 , 16 , 18 may be made of separate pieces of material that are joined together, or can be made of a single piece of material, or various pieces of material joined in varying manners, etc. The left front panel 14 and right front panel 16 may each have an inner edge 20 that are releasably attachable together by a fastener 22 , such as a zipper, snaps, clasps, clips, hook-and-loop fastening material (i.e., VELCRO® fastening material), combinations of these components or the like. The body portion 12 defines a torso portion/torso cavity 24 that is shaped to receive a wearer's torso 26 therein (see FIGS. 2 and 3 ). The coat 10 may include a pair of sleeves 28 coupled to and extending generally outwardly from the body portion 12 that are shaped to receive a wearer's arms therein. [0011] The coat 10 may include various layers through its thickness to provide various heat, moisture and abrasion resistant qualities to the coat 10 so that the coat 10 can be used as a protective, hazardous duty, and/or firefighter garment. For example, the coat 10 may include an outer shell 30 , a thermal liner or barrier 32 located inside of and adjacent to the outer shell 30 , and a moisture barrier/vapor barrier 34 located inside of and adjacent to the thermal barrier 32 . A second thermal liner 36 may be located inside of and adjacent to the moisture barrier 34 , and an inner liner or inner face cloth 38 may be located inside of and adjacent to the second thermal liner 36 . [0012] The outer shell 30 may be made of or include a variety of materials, including a flame, heat and abrasion resistant material such as a compact weave of aramid fibers and/or polybenzamidazole fibers. Commercially available aramid materials include NOMEX and KEVLAR fibers (both trademarks of E.I. DuPont de Nemours & Co., Inc. of Wilmington, Del.), and commercially available polybenzamidazole fibers include PBI fibers (a trademark of PBI Performance Fabrics of Charlotte, N.C.). Thus, the outer shell 30 may be an aramid material, a blend of aramid materials, a polybenzamidazole material, a blend of aramid and polybenzamidazole materials, or other appropriate materials. If desired, the outer shell 30 may be coated with a polymer, such as a durable, water repellent finish (i.e. a perfluorohydrocarbon finish, such as TEFLON® finish sold by E. I. Du Pont de Nemours and Company of Wilmington, Del.). The materials of the outer shell 30 may have a weight of, for example, between about five and about ten oz/yd 2 . [0013] The moisture barrier 34 and thermal liners 32 , 36 may be generally coextensive with the outer shell 30 , or spaced slightly inwardly from the outer edges of the outer shell 30 (i.e., spaced slightly inwardly from the outer ends of the sleeves 28 , the collar 40 (or the upper edge of the collar 40 ) and from the lower edge 41 of the coat 10 ) to provide moisture and thermal protection throughout the coat 10 . The thermal liner 32 may be made of nearly any suitable material that provides sufficient thermal insulation. In one embodiment, the thermal liner 32 may include a relatively thick (i.e. between about 1/16″- 3/16″) batting, felt or needled non-woven bulk or batting material 32 a. The bulk material 32 a can also take the form of one or two (or more) layers of E-89® spunlace fabric made of a combination of NOMEX® and KEVLAR® fabric. The bulk material 32 a can also, or instead, include aramid fiber batting (such as NOMEX® batting), aramid needlepunch material, an aramid non-woven material, an aramid blend needlepunch material, an aramid blend batting material, an aramid blend non-woven material, foam (either open cell or closed cell), or other suitably thermally insulating materials. The bulk material 32 a may trap air and possess sufficient loft to provide thermal resistance to the coat 10 . [0014] The bulk material 32 a may be quilted to a thermal liner face cloth 32 b which can be a weave of a lightweight aramid material. Thus, either the bulk material 32 a alone, or the bulk material 32 a in combination with the thermal liner face cloth 32 b, may be considered to constitute the thermal liner 32 . In the illustrated embodiment, the bulk material 32 a is located between the outer shell 30 and the thermal liner face cloth 32 b. However, the orientation of the thermal liner 32 may be reversed such that the thermal liner face cloth 32 b is located between the outer shell 30 and the bulk material 32 a. If desired, the thermal liner 32 , or parts thereof, may be treated with a water-resistant or water-repellent finish. [0015] The second thermal liner 36 may have the same qualities and properties as the thermal liner 32 described above. For example, the second thermal liner 36 may have a bulk material 36 a and a liner 36 b. However, the liner 36 b may be omitted, and, for example, inner liner 38 may form the liner for the bulk material 36 a of the second thermal liner 36 . Moreover, the second thermal liner 36 may be completely omitted if desired, or omitted in only certain parts of the coat 10 , as will be described in greater detail below. In locations where the second thermal liner 36 is omitted, the thermal protective qualities of the thermal liner 32 may be increased to account for the omission of the second thermal liner 36 , as described in greater detail below. [0016] In one embodiment, the thermal liner 32 (or the combined qualities of the liners 32 , 36 ) may have a thermal protection performance (“TPP”) of at least about twenty, and in another embodiment, at least about thirty five. Moreover, in one embodiment the coat 10 as a whole has a TPP of at least about twenty, and in another embodiment has a TPP of at least about thirty-five. [0017] The moisture barrier 34 may include a semi-permeable membrane layer 34 a and substrates 34 b, 34 c positioned on either side thereof. The membrane layer 34 a may be generally water vapor permeable but generally impermeable to liquid moisture. The membrane layer 34 a may be made of or include expanded polytetrafluoroethylene (“PTFE”) such as GORE-TEX or CROSSTECH materials (both of which are trademarks of W.L. Gore & Associates, Inc. of Newark, Del.), polyurethane-based materials, neoprene-based materials, cross-linked polymers, polyamid, GORE® CHEMPAK® materials, sold by W.L. Gore & Associates, Inc. including GORE® CHEMPAK® Ultra Barrier Fabric, GORE® CHEMPAK® Selectively Permeable Fabric, or GORE® CHEMPAK® Sorptive Fabric, or other materials. [0018] The membrane layer 34 a may have microscopic openings that permit moisture vapor (such as water vapor) to pass therethrough, but block liquids (such as liquid water) from passing therethrough. The membrane layer 34 a may be made of a microporous material that is either hydrophilic, hydrophobic, or somewhere in between. The membrane layer 34 a may also be monolithic and may allow moisture vapor transmission therethrough by molecular diffusion. The membrane layer 34 a may also be a combination of microporous and monolithic materials (known as a bicomponent moisture barrier), in which the microporous or monolithic materials are layered or intertwined. [0019] The membrane layer 34 a may be bonded or adhered to substrates 34 b, 34 c of a flame and heat resistant material on either side thereof to provide structure and protection to the membrane layer 34 a. Each substrate 34 b, 34 c may be or include aramid fibers similar to the aramid fibers of the outer shell 30 , but may be thinner and lighter in weight. Each substrate 34 b, 34 c may be woven, non-woven, spunlace or other materials. If desired, and in certain embodiments, the moisture barrier 34 may include only a single substrate on one side thereof. [0020] In FIG. 1 the thermal liner 32 is shown as being positioned between the outer shell 30 and the moisture barrier 34 . However, if desired, and for use in certain applications, the positions of the moisture barrier 34 and thermal liner 32 may be reversed such that the moisture barrier 34 is located between the outer shell 30 and the thermal liner 32 . In addition, the second thermal liner 36 can be positioned at various locations throughout the thickness of the coat 10 . [0021] The inner face cloth 38 may be the innermost layer of the coat 10 , located inside the thermal liners 32 , 36 /moisture barrier 34 . The inner face cloth 38 can provide a comfortable surface for the wearer and protect the thermal liners 32 , 36 and/or moisture barrier 34 from abrasion and wear. The inner face cloth 38 may be quilted to the adjacent layer (i.e. the second thermal liner 36 in the embodiment of FIG. 1 ). The coat 10 may include various arrangements of liners/materials, as desired, in which the various layers described herein are included, omitted, and/or rearranged. For example, the coat 10 may lack any thermal liner 32 , 36 , and include only an outer shell 30 , moisture/vapor barrier 34 and inner face cloth 38 , or may include only an outer shell 30 and a moisture/vapor barrier 34 , or may include only a moisture/vapor barrier 34 , or may take on various other configurations as desired. [0022] Each layer of the coat 10 , and the coat 10 as a whole, may meet the National Fire Protection Association (“N.F.P.A.”) 1971 standards for protective firefighting garments (“Protective Clothing for Structural Firefighting”), which are entirely incorporated by reference herein. The NFPA standards specify various minimum requirements for heat and flame resistance and for tear strength. For example, in order to meet the NFPA standards, the outer shell 30 , moisture barrier 34 , thermal liners 32 , 36 and inner face cloth 38 must be able to resist igniting, burning, melting, dripping, separation and/or shrinking by more than 10% in any direction at a temperature of 500° F. for at least five minutes. Furthermore, in order to meet the NFPA standards, the combined layers of the coat 10 must provide a thermal protective performance rating of at least thirty-five. [0023] With reference to FIG. 2 , the coat 10 may include a vapor skirt 42 . The vapor skirt 42 can take the form of a generally flat, rectangular piece of material (when laid flat) coupled to an inner surface of the coat 10 . The vapor skirt 42 may be coupled to the inner surface of the coat 10 along the entire or substantially the entire inner perimeter of the coat 10 /torso portion 24 at a vertical height position 44 (also see FIG. 1 ). The skirt 42 /coat 10 are configured such that when the coat 10 is closed, the vapor skirt 42 may extend about 360 degrees about the wearer 26 , as shown in FIG. 3 . [0024] The vapor skirt 42 may have an elastic material 48 coupled to or forming an inner edge 46 thereof to ensure that the vapor skirt 42 contacts and generally forms a seal with the wearer 26 (i.e. the wearer's clothes) and generally blocks ambient and superheated vapors from extending upwardly past the vapor skirt 42 . [0025] In particular, in the illustrated embodiment the vapor skirt 42 includes a strip of elastic material 48 positioned on or adjacent to its inner edge 46 . As shown in FIG. 3 , when the coat 10 is closed, the elastic material 48 is stretched such that the inner edge 46 of the vapor skirt 42 fits around, and conforms to, the torso/body of the wearer 26 . Thus in this configuration when the coat 10 is closed the vapor skirt 42 is generally “disc” shaped with a central opening that corresponds to the torso of the wearer 26 . [0026] As shown in FIG. 2 , when the coat 10 is opened (i.e. the left front panel 14 is not attached to the right front panel 16 and the panels 14 , 16 are moved apart, and/or when the coat 10 is not being worn), the elastic material 48 retracts to its unstressed or undeformed shape, thereby gathering the material of the skirt 42 . The elastic material 48 may stretch between about 15%-75% (about 50%, in one case) when the coat 10 moves from its open position to its closed position, and return to its original state when the stretching forces are removed. It may be desired to configure the elastic material 48 so that when the coat 10 is closed and the vapor skirt 42 is deployed, the vapor skirt 42 is stretched smooth and flat, with little or no bunching at or adjacent to the elastic material 48 so that the vapor skirt 42 forms a good and relatively tight seal with the wearer. If there is too much elastic material 48 (or the elastic material 48 is too strongly elastic) then the vapor skirt 42 will not be pulled tight and will remained bunched up at or adjacent to the elastic material 48 when the vapor skirt 42 is employed. Conversely if there is not enough elastic material 48 (or the elastic material 48 is too weakly elastic) the vapor skirt 42 may not be about to be stretched about a wearer. Accordingly, the amount and strength of the elastic material 48 may be selected to ensure a proper seal is formed with wearers of a variety of sizes and shapes. [0027] In the embodiment of FIG. 4 , the material of the vapor skirt 42 forms or is formed into a closed loop 50 at its inner edge 46 , and the elastic material 48 is positioned in, or captured in, the loop 50 . This configuration protects the elastic material 48 , and allows the material of the skirt 42 (and the loop 50 ) to slide freely relative to the elastic material 48 as the elastic material 48 is stretched and retracts. In this embodiment, a gripping material 52 (such as rubber, synthetic rubber, or the like) may coupled to the radially inner edge 46 of loop 50 . The gripping material 52 helps to ensure that the inner edge 46 of the loop 50 frictionally engages the wearer's torso 26 (or clothing) to ensure a relative tight seal therewith, as shown in FIG. 3 . [0028] FIG. 5 illustrates an alternate embodiment wherein the vapor skirt 42 lacks the closed loop 50 . In this embodiment the elastic material 48 is directly attached to the inner edge 46 of the skirt 42 , such as by stitching, adhesives or the like. In this embodiment the elastic material 48 may act as a gripping surface which frictionally grips the wearer's torso, and a separate gripping surface may not be needed. [0029] The seal formed by the vapor skirt 42 can help to prevent the introduction of harmful materials into the torso cavity 24 of the coat 10 . Such harmful materials may include liquids (including chemical warfare agents, biological warfare agents and toxic industrial chemicals), vapors and aerosols (including chemical warfare agents and toxic industrial chemicals), and contaminated particulates (such as biological warfare agents). Examples of chemical warfare agents include soman (GD) nerve agent and distilled mustard (HD) blister agent. Examples of toxic industrial chemicals include acrolein (liquid), acrylonitrile (liquid), ammonia (gas), choline (gas), and dimethyl sulfate (liquid). However, it should be understood that the vapor skirt 42 can be utilized to prevent or minimize the introduction of nearly any desired material, gas, fluid, liquid, particulate solids, etc. into the torso cavity 26 , including smoke, water vapor, liquid water, etc. [0030] The vapor skirt 42 helps to form a seal and prevent, or significantly limit, the introduction of undesired materials into the torso cavity 24 above the vapor skirt 42 . NFPA 1971 standards include a Chem/Bio Option (the entire contents of which are hereby incorporated by reference) which provides specifications that protective ensembles must meet in order to be certified under that Option. For example, the Chem/Bio Option specifies that the garment must pass a MIST test (Man-In-Simulant-Test). In one case the MIST test essentially consists of introducing the garment 10 and a wearer (or mannequin) into a chamber filled with a vaporized test material (such as oil of wintergreen). Absorbent padding is placed on the wearer of the garment 10 , and/or inside the garment. After the garment 10 has been exposed to the vaporized material for a sufficient period of time, the garment 10 is removed from the chamber. The absorbent pads are removed and analyzed to determine how much of the vaporized test material they have absorbed. The vapor skirt 42 , in combination with various other protective features, may provide a garment/ensemble which passes the MIST test, and more broadly, which meets the Chem/Bio Option of NFPA 1971 standards. [0031] The vapor skirt 42 can be made of a variety of materials. For example, the vapor skirt 42 can be made of the same materials of the moisture barrier/vapor barrier 34 , which are described above. The advantage of this arrangement is that a separate material for the vapor skirt 42 does not have to be handled by the manufacturer. For example, the skirt 42 and/or moisture barrier 34 may be made of made of or include PTFE (such as GORE-TEX or CROSSTECH materials), polyurethane-based materials, neoprene-based materials, cross-linked polymers, polyamid, or GORE® CHEMPAK® materials, sold by W.L. Gore & Associates, Inc. including GORE® CHEMPAK® Ultra Barrier Fabric, GORE® CHEMPAK® Selectively Permeable Fabric, or GORE® CHEMPAK® Sorptive Fabric. The moisture barrier 34 and/or vapor skirt 42 may also include one or both of the substrates 34 b, 34 c described above. [0032] As noted above, the membrane layer 34 a of the moisture barrier 34 and/or the skirt 42 may be generally water vapor permeable but generally impermeable to liquid moisture. In this case the skirt 42 may allow water vapor to pass through (to allow venting), but block harmful materials due to the differing molecule size of water vapor and the harmful materials. Besides the materials outlined above, the skirt 42 can be made of nearly any material that is generally impermeable to the unwanted materials. [0033] Rather than being made of the same material as the moisture barrier 34 , the vapor skirt 42 can instead be made of a different material than that of the moisture barrier 34 . In this case the vapor skirt 42 may be made of a generally liquid and/or vapor and/or gas impermeable material, such as neoprene. The advantage of this arrangement is that a cheaper material, or a material that is more effective at blocking the undesired material, can be utilized in the vapor skirt 42 . Moreover, if desired, the moisture barrier/vapor barrier 34 can be made of a generally liquid and/or vapor and/or gas impermeable material, such as neoprene. [0034] The vapor skirt 42 may be attached to the moisture barrier 34 so as to form a seal therewith. In particular, as shown in FIG. 4 , the moisture barrier 34 of the garment may include an upper moisture barrier portion 34 ′ positioned above the vapor skirt 42 and a lower moisture barrier portion 34 ″ positioned below the vapor skirt 42 . Similarly, the inner-most inner face cloth 38 may include an upper face cloth portion 38 ′ and a lower face cloth portion 38 ″. The inner edge of the vapor skirt 42 may extend through the face cloth portions 38 ′, 38 ″ and moisture barrier portions 34 , 34 ′. [0035] In the illustrated embodiment the second thermal liner portion 36 is positioned only in the upper portion of the garment; that is, between the upper face cloth portion 38 ′ and the upper moisture barrier portion 34 ′. In this case the second thermal liner portion 36 is not provided below the skirt 42 . However, in order to accommodate for the lack of the additional thermal liner portion 36 below the vapor skirt 42 , a supplemental thermal liner portion 32 ′ is provided below the vapor skirt 42 , and coupled to the thermal liner 32 . FIG. 4 illustrates the supplemental thermal liner portion 32 ′ as a separate thermal liner attached to the thermal liner 32 . However, if desired the supplemental thermal liner 32 ′ may take the form of increased thickness and/or weight which is unitary/integral, and formed as one piece with, the remainder of the thermal liner 32 , as shown in FIG. 5 . Moreover, if desired, the coat 10 may have the same arrangement of the thermal liner 32 and/or 36 below the vapor skirt 42 as is provided above the vapor skirt 42 , or the lower arrangement shown herein may be provided above the vapor skirt 42 . In addition, as noted above the coat 10 may include various arrangements of liners/materials, as desired. For example, the coat 10 may lack any thermal liner 32 , 32 ′, 36 , and include only an outer shell 30 and moisture/vapor barrier 34 , etc. The garment 10 need not necessarily be NFPA compliant, and could be a non-NFPA compliant garment. [0036] The vapor skirt 42 may include an extension portion or a vertically flared portion 42 ′ sandwiched between the moisture barrier portions 34 ′, 34 ″ with stitching 56 extending through all three layers 34 ′, 42 ′, 34 ″. The lower moisture barrier portion 34 ″ may have a looped upper end that is attached by the stitching 56 . The upper moisture barrier portion 34 ′, second thermal liner 36 and upper face cloth portion 38 ′ may be attached by stitching 58 (positioned just above the vapor skirt 42 ), and the lower moisture barrier portion 34 ″ and lower face cloth portion 38 ″ may be attached by stitching 60 (positioned just below the vapor skirt 42 ). [0037] A sealing material 62 may be provided and extend between the upper face cloth portion 38 ′ and the vapor skirt 42 , and another piece of sealing material 62 extends between the lower face cloth portion 38 ″ and the vapor skirt 42 . In one embodiment, the sealing material 62 is a tape made of the same materials as the membrane 34 a of the moisture barrier 34 (such as PTFE), or the materials of the vapor skirt 42 , with an adhesive applied thereto, although the sealing material 62 can take a variety of other forms, including sealants applied in a liquid form and cured into a solid. This arrangement ensures that a generally continuous moisture barrier/harmful material barrier is maintained within the garment 10 which prevents undesired penetration of moisture/harmful material. In addition, to the extent the stitching 56 , 58 , 60 compromises the sealed integrity of the garment 10 , the tape/sealant 62 helps to minimize the effects of such a compromise. [0038] As shown in FIG. 2 , the vapor skirt 42 may be attached to the garment 10 along a pair short, vertical side seams 64 adjacent to the front of the coat 10 (adjacent to the edges 20 ), and along a longer horizontal seam 66 extending substantially the entire perimeter/width of the coat 10 (at the height location 44 ). In this manner, the skirt 42 may be permanently and fixedly coupled to the coat 10 , such as by stitching, adhesives, etc. This arrangement ensures that, whenever the coat 10 is closed (i.e. when the left front panel 14 and right front panel 16 are joined) the vapor skirt 42 forms a seal around the wearer 26 and helps to limit the introduction of harmful materials. Thus, this configuration provides a “always-on” feature such that the wearer 26 does not need to remember to secure the vapor skirt 42 , or carry out any other operations, to obtain the benefit of the protection of the vapor skirt 42 . In addition, the “always on” feature ensures that, should the wearer unexpectedly enter a hazard zone which includes harmful materials, the wearer does not need to open the coat 10 to ensure that the vapor skirt 42 is in a protective position. If the wearer were required to open the coat 10 in a hazard zone, the wearer's exposure to harmful materials is significantly increased while the coat 10 is opened, thereby defeating the very purpose of the protective nature of the garment 10 . [0039] Alternately, if desired, the vapor skirt 42 may be releasably/removably coupled to the coat 10 . For example, if desired, one or both of the side seams 64 of the vapor skirt 42 may be releasably coupled to the inner surface of the coat 10 by zippers, snaps, clasps, clips, hook-and-loop fastening material, combinations of these components, etc. This arrangements eliminates “pulling,” or resistance of the coat 10 to being closed due to the stretching of the elastic material 48 of the vapor skirt 42 . Alternately, or in addition, the outer edge 66 of the vapor skirt 42 may be releasably coupled by the same or similar means as the side edges 64 . In one embodiment, both the sides 64 and outer edge 66 of the vapor skirt 42 are releasably/removably attached such that the entire vapor skirt 42 is removable from the coat 10 to allow repair, replacement or cleaning thereof. [0040] The outer edge 66 /height location 44 of the vapor skirt 42 may be spaced from the bottom edge 41 the coat 10 by between about zero to about eighteen inches. It may be desired to space the vapor skirt 42 from the bottom edge 41 of the coat 10 to allow easy opening/closing of the coat 10 and to protect the vapor skirt 42 from abrasions, punctures, etc. However, if the vapor skirt 42 is positioned too high, its protective benefits are reduced. In particular, it may be desired to ensure that the vapor skirt 42 is not positioned above the upper edge (i.e. the waist edge) of a pair of trousers worn win the coat 10 , to ensure that harmful materials are also prevented from entering the trousers. [0041] If desired, the coat 10 may include a “chest gatherer” system to help reduce the volume of air trapped inside the coat 10 . For example, U.S. Pat. No. 5,157,790 to Aldridge, the entire contents of which are incorporated herein, discloses a lumbar support in the form elastic bands or strips extending around the waist portion of the garment. The straps can be pulled tight around the wearer's body and attached to each other. A similar arrangement can be utilized in the chest of the coat 10 (i.e. the straps can be positioned under the arms 28 of the coat 10 .) In this case, when the chest gatherer is utilized, the volume of air retained within the coat 10 is reduced, and therefore the volume of harmful materials able to enter the torso cavity 24 of the coat 10 is correspondingly reduced. The reduced volume inside the coat 10 works in concert with the vapor skirt 42 to protect the wearer. [0042] The coat 10 may include various other features to protect from harmful materials. For example, a hood, in the form of a one-piece or split hood (not shown), may be utilized to fit around a wearer's head, which can engage with a mask to form a fluid-tight ensemble. [0043] Although the invention is shown and described with respect to certain embodiments, it should be clear that modifications will occur to those skilled in the art upon reading and understanding the specification, and the present invention includes all such modifications.	A coat including a torso portion defining a torso cavity and including pair of portions that are releasably connectable together. The coat further includes a skirt positioned in the torso cavity. The coat is configured such that when the coat is worn by a wearer and the portions are releasably connected together the skirt generally sealingly engages the wearer. The coat is further configured such that the skirt automatically generally sealingly engages the wearer when the coat is worn by the wearer and the portions are releasably connected without requiring any further action by the wearer.	0
TECHNICAL FIELD [0001] This invention relates to graphical user interfaces for defining categorization schemes that are used by computer-executed processes to categorize content. BACKGROUND [0002] This document describes the use of graphical user interfaces (GUIs) to develop categorization schemes that computer-executed processes can use to categorize information, especially information contained in electronic messages. Exemplary processes that use categorization schemes may be designed to be executed on enterprise computing systems. One such enterprise computing system involves software for performing business processes that include responding to large volumes of inbound communications from customers. Such inbound communications are typically in the form of email messages, but they may also include other forms of inbound data, such as information entered by a customer over the Internet directly into a form located on an enterprise's website. [0003] The productivity of an individual agent who is responsible for responding to large volumes of inbound communications affects the cost of performing that particular business process. However, in controlling the cost, the quality of the responses should be maintained so that the customer is well served. Thus, systems used to respond to inbound communications should provide high quality responses in an efficient manner. [0004] Systems that respond to high volumes of inbound emails may be called Email Response Management Systems (ERMS). By using an enterprise computing system to automate some of the steps of an ERMS, the process of responding to a large volume of inbound e-mails can be made more efficient and cost-effective. As such, an enterprise can use ERMS software to enhance productivity. [0005] To realize maximum productivity gains in the run-time environment, an enterprise usually must first customize the ERMS software in the design-time environment. Specifically, the ERMS software must be configured to perform the particular business process steps required by a particular enterprise. In addition, the enterprise must be able to reconfigure the ERMS software to reflect changes in the enterprise's business process steps over time. Thus, an enterprise should be able to customize and to maintain ERMS software so that productivity gains can be maximized. [0006] When an enterprise uses ERMS software to handle a large volume of inbound email messages, for example, it is important for the enterprise to quickly and accurately determine how to respond to received messages. For one message, an appropriate response may be to ship a product to a customer. For other messages, an appropriate response may be to provide a map of driving directions, or to contact a subject matter expert who can answer detailed technical questions. Accordingly, some ERMS systems make classification decisions to determine how to respond to each received message. [0007] That classification decision can be partially or wholly automated by using computer-executed processes to rapidly review the received messages and to determine how each should be classified so that the enterprise can take appropriate steps to respond to each message. The classification decision may be used, for example, to retrieve stored information from a database. The stored information may then be automatically suggested to an agent who is responsible for responding to the message. Because the content of the message has already been classified, only stored information that has predefined associations to the content of the message are suggested to the agent. As such, the agent does not need to manually search for the stored information, which would take more of the agent's time. In enterprises in which an agent is responsible for responding to many hundreds of messages each day, reducing the time required for an agent to respond to each message can significantly improve productivity and reduce the overall cost of responding to received messages. SUMMARY [0008] This document describes a graphical user interface (GUI) tool for maintaining categorization schemes in enterprise computing systems. Categorization is used to automate the process of categorizing business documents and business objects. Categorization may be used to improve productivity achieved by enterprise computing software that performs steps in a business process (or in multiple business processes). In order to take full advantage of categorization, an enterprise needs a cost-effective tool for developing and maintaining categorization schemes. [0009] In one aspect, a computer program product tangibly embodied in an information carrier includes instructions that, when executed, generate on a display device a GUI. The GUI is for editing a data structure to be used by a computer-executed process that categorizes data. The GUI includes a categorization area that displays user-input fields which may be used to define a number of categories and a number of links that form a categorization scheme. Each category corresponds to certain content associated with that category. Each category is defined to be at one of a series of levels between a top level and a bottom level. At each level below the top level, each category is linked by one of the number of defined links as a child category to a corresponding parent category. The parent category is one of the categories defined in the level immediately above the child category. Each child category corresponds to certain content that is a sub-set of the content that corresponds to the corresponding parent category. The categorization scheme is organized to enable the computer-executed process to categorize the data. The categorization causes the selection of categories that correspond to the data. The selection is made by making a category determination beginning at the top level and proceeding to the children of categories that correspond to the data. [0010] In another aspect, a system for responding to a received message includes an information repository and a software program. The information repository includes a number of categories and a number of links that form a categorization scheme. Each category corresponds to certain content associated with that category, and each category is defined to be at one of a series of levels between a top level and a bottom level. Each category at a level below the top level is linked by one of the number of defined links as a child category to a corresponding parent category. The parent category is one of the categories defined in the level immediately above the child category. Each child category corresponds to certain content that is a sub-set of the content that corresponds to the corresponding parent category. The categorization scheme is organized to enable a categorization of the content of the received message. The categorization causes categories that correspond to the content of the received message to be selected. The selection is made by making a category determination beginning at the top level and proceeding to the children of categories that correspond to the content of the received message. The software program is tangibly embodied in an information carrier and includes instructions. When executed, these instructions categorize the content of the received message into at least one of the categories in the categorization scheme. Subsequent processing resulting from the received message depends on the categorization. [0011] In another aspect, a method defines a data structure to be used by a computer-executed process to categorize content of a received message into at least one of a number of defined categories. The method includes a step of inputting categorization scheme information into user-input fields displayed in a categorization area of a GUI. The categorization scheme information includes a number of categories and a number of links. Each category corresponds to certain content associated with that category. Each category is defined to be at one of a series of levels between a top level and a bottom level. Each category at a level below the top level is linked by one of the number of defined links as a child category to a corresponding parent category. The parent category is one of the categories defined in the level immediately above the child category. Each child category corresponds to certain content that is a sub-set of the content that corresponds to the corresponding parent category. The categorization scheme is organized to enable the computer-executed process to categorize the content of the received message. The categorization causes categories that correspond to the content of the received message to be selected. This selection is made by making a category determination beginning at the top level and proceeding to the children of categories that correspond to the content of the received message. [0012] In modifications, the method may further include the step of defining links using a linking area displayed in the GUI. These links define associations between categories defined in the categorization area and stored information. The computer-executed process, when executed, uses the stored information that is linked to the selected categories to perform subsequent processing of the received message. [0013] In another aspect, a computer program product tangibly embodied in an information carrier includes instructions that, when executed, generate on a display device a GUI for editing a data structure to be used by a computer-executed process that categorizes content of a received message. The GUI includes a categorization area and a linking area. The categorization area displays user-input fields which may be used to define a number of categories and a number of links that form a categorization scheme. Each category corresponds to certain content associated with that category, and is defined to be at one of a series of levels between a top level and a bottom level. Each category at a level below the top level is linked by one of the number of defined links as a child category to a corresponding parent category. The parent category is one of the categories defined in the level immediately above the child category. Each child category corresponds to certain content that is a sub-set of the content that corresponds to the corresponding parent category. The categorization scheme is organized to enable the computer-executed process to categorize the content of the received message. This categorization causes categories that correspond to the content of the received message to be selected. This selection is made by making a category determination beginning at the top level and proceeding to the children of categories that correspond to the content of the received message. The linking area displays user-input fields which may be used to define associations between categories defined in the categorization area and stored information. The computer-executed process, when executed, uses the stored information that is linked to the selected categories to perform subsequent processing of the received message. [0014] Various modifications to the foregoing aspects are possible. For example, the computer program product may further include a linking area that displays user-input fields which may be used to define associations between categories defined in the categorization area and stored information. In addition, the computer-executed process, when executed, uses the stored information that is linked to the selected categories to perform subsequent processing of the data. [0015] In some modifications, the linking area may further display a number of user-selectable links. Each such link corresponds to a viewset that displays user-input fields which may be used to define associations between categories defined in the categorization area and stored information. One of such user-selectable links may correspond to a viewset that displays user-input fields which may be used to define associations between categories defined in the categorization area and any of documents, experts, or response templates. One of the user-selectable links may also correspond to a viewset that displays either a query input area for entering criteria that defines the content that corresponds to each category, or a preview area for viewing selected stored information. The GUI may also display in the categorization area user-selectable buttons that, when selected, enable information in the user-input fields to be edited using cut and paste functionality. [0016] The linking area may further display an application area which may be used to define associations between categorization schemes that have been defined in the categorization area and pre-defined business processes that categorize the data. In that case, the linking area may be used to associate a number of business processes with a categorization scheme. Furthermore, at least two of the number of associated business processes can be executed using stored information determined to be linked to categories selected during a single categorization of the data. The categorization area may further display selectable buttons which may be used to change the level at which a category is defined. [0017] The categorization area may further display selectable buttons associated with each parent category, wherein each parent category may be selectively displayed in an expanded form in which all child categories are graphically displayed, and selectively displayed in a collapsed form such that no child categories are graphically displayed. [0018] In other modifications, the stored information may be stored in a number of memory locations in an enterprise computing system. The data may comprise content of a received message or comprise business objects. Such business objects may include stored documents or stored response templates. [0019] In the foregoing examples, categorization schemes may be defined and maintained by an enterprise to obtain operational efficiencies provided by categorization schemes generally, and coherent categorization schemes in particular. The described graphical user interface provides a convenient, integrated tool for designing and maintaining hierarchical categorization schemes, and for defining links from categories to stored business objects. Use of this tool promotes effective utilization of categorization schemes by providing an easy-to-use interface that an enterprise can self-maintain and adapt over time as business processes evolve. [0020] The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. DESCRIPTION OF DRAWINGS [0021] FIG. 1 is an enterprise computing system. [0022] FIGS. 2A-2B are run-time flow diagrams of a business application using a coherent categorization scheme. [0023] FIG. 3A is a categorization scheme. [0024] FIG. 3B is a portion of the categorization scheme of FIG. 3A with additional detail. [0025] FIG. 3C is a conceptual diagram of the process steps performed when manually selecting a category in a categorization scheme in accordance with FIG. 2B . [0026] FIG. 3D is a user interface for manually selecting categories using the process of FIG. 3C . [0027] FIGS. 4-10 are screenshots of a design-time user interface for defining categorization schemes according to FIGS. 3A-3B . [0028] FIG. 11 is a flowchart of the steps to define a categorization scheme using the GUI of FIGS. 4-10 . [0029] Like reference symbols in the various drawings indicate like elements. DETAILED DESCRIPTION [0030] This document describes a graphical user interface (GUI) that an enterprise can use to develop and maintain categorization schemes. First, it introduces a computing environment in which categorization schemes may be developed, maintained, and used. Then, for ease of understanding, it next describes categorization schemes themselves, including various run-time and structural aspects. Then, the document presents the GUI that an enterprise can use to develop and maintain the described categorization schemes. [0031] The introduction begins with an exemplary computing environment in which an enterprise may develop, maintain, and use categorization schemes for an exemplary business application, which could be an email response management system (ERMS). The enterprise computing system 10 that may be used to design and run (i.e., execute) the business application is shown in FIG. 1 . The system 10 includes a design-time environment 12 in which a business application may be designed to meet the needs of a particular application. The system 10 also includes a run-time environment 14 in which the business application operates after its design has been completed. Stored information 22 relating to the business application is accessible by both the design-time and run-time environments 12 , 14 . [0032] To design and execute a business application, information is moved, processed, and stored in the system 10 . The design-time environment 12 is connected to a network 16 by connection 18 , and the run-time environment 14 is connected to the network 16 by connection 20 . The network 16 , which may be, for example, an intranet, provides for communications within and between the design-time environment 12 and stored information contained in the repository 22 . The network 16 also provides for communication over connection 20 between the run-time environment 14 and the stored information repository 22 . The stored information container repository 22 may include knowledge bases, databases, application programs, and other information accessible by elements of the design environment 12 and the run-time environment 14 . A user in the design-time environment 12 may use a computer terminal 22 to enter, modify, and remove information that may include information stored on the stored information repository 22 . Similarly, a user in the run-time environment 14 uses a computer terminal 26 to perform run-time applications that can use access, modify, and delete information stored in the stored information repository 22 . [0033] In the design-time environment 12 , software developers, for example, use various tools, including editors, debuggers and compilers, in order to develop software modules, user interfaces, executable programs, and the like, for use in the run-time environment 14 . In developing such run-time environment applications, a user in the design-time environment 14 loads stored information from the stored information repository 22 through the network 16 and into the terminal 24 in order to manipulate that information. For example, the design-time environment 12 user may load application programs from the stored information repository 22 and use those application programs to create, for example, categorization schemes. These created categorization schemes can incorporate business objects and other data that is also loaded from the stored information repository 22 into terminal 24 in the design-time environment. The user can then store the modified categorization scheme, of this example, back into the stored information repository 22 where it may be accessed from the terminal 26 in the run-time environment 14 . Accordingly, the user in the design-time environment 12 can store data and programs in the stored information repository 22 that the user in the run-time environment can use to perform run-time applications. Moreover, the run-time environment user may also manipulate stored information in the stored information repository 22 . As such, the run-time environment 14 may affect the data in the stored information repository 22 that is subsequently used within the design-time environment 12 . [0034] The enterprise computing system 10 may be connected to additional networks, for example, the Internet. Although not shown in FIG. 1 , the Internet may be connected to the design-time environment 12 , the run-time environment 14 , or the network 16 using standard communication interface hardware and software techniques. [0035] After a business application has been designed in the design-time environment 12 , the business application can be executed in the run-time environment 14 . Referring to FIGS. 2A-2B , a run-time flow diagram illustrates execution of a business application that uses coherent categorization to perform multiple business process steps. FIGS. 2A-2B illustrate use of coherent categorization schemes in two exemplary versions of the business application, namely a manual categorization, and an automated categorization. [0036] In the manual version shown in FIG. 2A , the business application 28 responds to an input signal 30 by producing an output signal 32 . A first business process module 34 executes instructions to perform one of the business application 28 business process steps. To perform that step, the module 34 categorizes the input signal 30 . As will be shown with respect to FIG. 5B , a human user manually selects a category displayed on a user interface. The business process module 34 displays categories from a categorization scheme 36 , and may limit the displayed categories to those that are relevant to performing the business process step 34 . Moreover, because the business application is structured to use the categorization scheme 36 , the selected category 38 may be used by a subsequent business process module 40 in the presence of the input signal 30 . [0037] Linked to the selected category 38 are linked business objects (BO's) 44 . The linked BO's 44 may include information, such as, for example, experts 46 , quick solutions 48 , and response templates 50 . Collectively, these linked BO's 44 may be used in multiple business processes, including business processes 34 , 40 . If the business application is an ERMS, for example, the input 30 may be an incoming e-mail message from a customer. In that case, the ERMS is used to respond to incoming e-mail messages by providing, for example, a reply e-mail message as the output signal 32 . [0038] The categorization scheme 36 is used in a coherent manner because it identifies a selected category 38 that provides relevant BO's 44 to more than one business process module, namely modules 34 , 40 . As such, the same categorization of an input signal is used to perform more than one business process step. In other words, each business process does not perform its own categorization, as was the case in prior art systems. [0039] A categorization is performed in response to a particular input signal 30 , and business processes are performed in reaction to (or in the presence on a particular input signal. As such, the particular selected category 38 is relevant to a business process only with respect to the content of a particular input signal 30 . The selected category may be different for each new incoming input signal. Accordingly, the particular category that is selected within the categorization scheme 36 will depend upon the content of a particular input signal 30 . [0040] In the automated version of this example shown in FIG. 2B , a categorization scheme is used to automatically suggest a category, but a user can override that suggestion by manually selecting a different category. For example, the business process module 34 uses the categorization scheme 36 to automatically propose suggested category 39 to subsequently-performed business process module 40 . In this example, the business process module 34 may include a content analysis engine for analyzing the content of the input signal 30 . In the process of performing the business process module 34 , the human user can choose to use the suggested category 39 to perform the business process module 40 , or the user can manually select a different category. Whichever category the user selects may be referred to as the selected category 38 . This selected category 38 is proposed to the subsequent business process step 42 . As such, business process module 42 may use the selected category 38 , or the user can override that choice and select a different category. [0041] To promote the efficient performance of the business process modules 40 , 42 , linked business objects 44 may be filtered to provide only those business objects that are relevant to the business processes 40 , 42 . A link 51 represents the link from the selected category 38 to the entire set of linked BO's 44 . A link 52 provides a subset of the linked BO's 44 to the business process 40 . A link 54 provides another subset of the linked BO's 44 to the second business process 42 . The business processes 40 , 42 can each use the independent subsets of linked BO's 44 provided by respective links 52 , 54 to perform their respective business processes within the business application 28 . [0042] The links 52 , 54 may provide the same subset of linked BO's 44 to both business processes 40 , 42 . On the other hand, the links 52 , 54 may provide subsets of linked BO's 44 that are different. In the latter case, each of the links 52 , 54 may be configured to provide BO's that are of a certain type. For example, if the business process 40 is performed to provide a standard e-mail response template, then the link 52 may be configured to provide only BO's that are of the response template 50 type. Similarly, if the business process 42 is performed to select documents for attachment to a reply e-mail, then the link 54 may be configured to provide only BO's that are of the quick solutions 48 type, or of the experts 46 type. [0043] Just as business objects are characterized by their type, each link between a category and a business object is characterized by a type. For example, a link from a category to a document of quick solution 48 type may be characterized as being of “is_solution” type. Similarly, links from categories to experts 46 and to response templates 50 may be characterized as being of “is_expert” and “is_response_template” types, respectively. [0044] The use of filtering may be illustrated, at least in part, in the context of an exemplary process of responding to an incoming email request that relates to printers. Initially, business process module 34 performs a content analysis of the input signal 30 , and it identifies the key word “printer” in the email. The categorization scheme has a category that corresponds to “printer,” so that category becomes the suggested category 39 . When the business process module 40 is performed, the suggested category 39 may be displayed to the user as a proposed category. If the user determines that the email relates specifically to “laser printers,” the user can override the suggested category by manually selecting a “laser printers” category that is a child of the “printers” category. Accordingly, the “laser printers” category becomes the selected category 38 . Having selected a category, business objects linked to the “laser printers” category may be provided to the business process module 40 by the link 52 . If, for example, the link 52 is configured to filter out business objects that are not of the response template 50 type, then only response templates 50 that are linked to the “laser printers” category are used. [0045] As will be shown in detail below, one exemplary run-time implementation of the coherent categorization scheme automatically displays only those business objects that are in the set of linked BO's 44 associated with the selected category 38 . In the exemplary business application 28 , BO's 44 that are not relevant to the business process being performed are, at least initially, filtered out. As such, they are not automatically provided to the business process. Instead, only those BO's most likely to be used are initially displayed to the user. Nevertheless, the user can choose to display business objects that are not linked to the selected category, if that is desired. [0046] By initially displaying only the linked BO's 44 , and by filtering out linked BO's that are not of the most relevant type to a business process, a categorization scheme reduces the time and effort the agent must spend performing a business process step. As such, the agent can realize productivity and efficiency improvements. If the categorization is also coherent, a single categorization can serve more than one business process step. By reducing the number of categorizations required to perform a number of business process steps, a coherently categorized system further reduces or eliminates unnecessary time and effort the agent must spend to perform multiple business process steps. As such, coherently categorized systems can yield further efficiency and productivity gains over systems that are not coherently categorized. [0047] The selection of categories to perform the foregoing exemplary business process steps depends on the structural details of the categorization scheme itself. The structures of two exemplary categorization schemes that may be used in the ERMS 28 of FIGS. 2A-2B are illustrated in FIGS. 3A-3B . In general, FIGS. 3A-3B illustrate how categorization schemes can be used to relate business process steps to relevant business objects, as well as how categorization schemes define relationships between categories. [0048] Referring to FIG. 3A , a set of business process steps 100 may be performed, either automatically or in response to user input, during the run-time execution of a business application. The steps in the set of business process steps 100 are linked to a set of categorization schemes 105 . Each categorization scheme in the set of categorization schemes 105 is linked, directly or indirectly, to multiple categories 110 . The categories may be distributed across any number of levels. For example, the categories may be arranged in a hierarchical structure having several levels, or they may be arranged in a flat structure in a single level. In hierarchically structured categories, each category below a top level is linked to one parent in the next higher level, and may be linked to any number of child categories in the next lower level. Parent/child categories may also be referred to as categories/sub-categories. Any of the categories 110 may be linked to one or more business objects 115 . [0049] Accordingly, the categorization schemes 105 relate business objects 115 to the business process steps 100 . By defining these associations, categorization schemes reflect relationships between business processes and resources (i.e., business objects), especially stored information, in the enterprise computing system 10 . Moreover, if a categorization scheme 105 identifies a selected category from among the categories 110 that subsequently provides relevant BO's 115 to more than one business process step 100 , then that categorization scheme 105 may be referred to as a “coherent” categorization scheme. In business application that includes coherent categorization, a single categorization may be used to provide business objects to multiple ERMS business process steps. As such, the categorization schemes 105 may reflect relationships across multiple business processes. [0050] For example, FIG. 3A shows an interaction record business process step 120 and an ERMS business process step 125 . The interaction record business process step 120 is linked by a link 130 to an interaction reason categorization scheme 135 . The ERMS business process step 125 is linked by a link 145 to the interaction reason categorization scheme 135 , and it is linked by a link 150 to the product categorization scheme 140 . Each of the categorization schemes 125 and 140 are linked to a number of categories. The interaction reason categorization scheme 135 is shown as having a hierarchical structure, while the product categorization scheme 140 is shown as having a flat structure. Under the interaction reason categorization scheme 135 , there is a link 155 to a LEGOLAND® category 160 , a link 165 to a Lego® club category 170 , and a link 175 to a Lego® products category 180 . The categories 160 , 180 have further sub-categories. The LEGOLAND® category 160 has a link 185 to an entry fee category 190 , a link 195 to an events category 200 , and a link 205 to a driving directions category 210 . Similarly, the Lego® products category 180 has a link 215 to a building instructions category 220 . Other links and categories may be added or removed from the interaction reason categorization scheme 135 to provide different responses for the business process steps 120 , 125 . [0051] By way of example, each of the categories 200 , 210 and 220 is linked to relevant business objects within the business objects 115 . For example, the events category 200 has a link 225 to a set of business objects 230 . As will be described with reference to FIG. 4 , the link 225 represents a set of links, whereby each business object in the set of business objects 230 has a uniquely defined link between each business object in the events category 200 . Similarly, the driving directions category 210 has a link 235 to a set of business objects 240 , and the building instructions category 220 has a link 245 to a set of business objects 250 . The sets of business objects 230 , 240 , 250 each include experts 46 , quick solutions 48 , and response templates 50 . [0052] As has been previously suggested, the sets 230 , 240 , 250 of business objects are selected from available business objects as being relevant to the categories to which they are linked. As such, the number of business objects of a particular type that are included within the particular set of business objects linked to a category can vary based on the number of business objects that are available. For example, the number of experts that are included in the set of linked business objects 230 , 240 , 250 depends upon the availability of subject matter experts who have knowledge relevant to the appropriate category. Similarly, the numbers of quick solutions 48 and response templates 50 that are included in a set of linked business objects 230 , 240 , 250 , depend upon the stored contents of, for example, a knowledge base within the stored information repository 22 ( FIG. 1 ). [0053] Accordingly, if the interaction record business step 120 is being performed in the presence of an input signal 30 (not shown), then content of the input signal 30 will determine how the categorization scheme 135 is navigated. If the content of the input signal 30 relates to driving directions to LEGOLAND®, then the categorization scheme would be navigated through the link 155 to the LEGOLAND® category 160 , and through the link 205 to the driving directions category 210 . If the ERMS business process step 125 is subsequently performed while responding to the same input signal 30 , then the business process step 125 will automatically receive business objects that relate to the chosen driving directions category 210 from the set of business objects 240 . [0054] Thus, in the foregoing example, the performance of the interaction record business process step 120 categorizes the input signal 30 to select and use the driving directions category 210 . The selected category may subsequently be used by a later business process step, in this example, the ERMS process step 125 . Accordingly, the exemplary categorization scheme just described exhibits coherency because a selected category identified in one step of a business process can be used to perform a subsequent business process step. [0055] Although the FIG. 3A represents only business object being linked to categories that exist at a lowest level (children) categories in the hierarchy, business objects may be also be linked to any category that is a parent category. As such, a categorization scheme may be defined such that any category that is selected may be linked to a set of business objects 44 . [0056] Additional structural detail of a categorization scheme in accordance with the categorization schemes of FIG. 3A is shown in FIG. 3B . In one example, FIG. 3B illustrates the selected category 38 in a magnified portion of a hierarchical categorization scheme 300 . The selected category 38 is linked by a link 305 to a parent category (not shown) above it. The selected category 38 is also linked to the linked business objects 44 . The selected category may exist at any level in the hierarchical categorization scheme 300 . Each of the linked business objects 44 are selected from among all available business objects that are stored, for example, in a database (not shown) in the enterprise computing system 10 . The linked business objects 44 may include experts 46 , quick solutions 48 , and/or response templates 50 . [0057] Each of the linked business objects 44 is linked to the selected category 38 by a unique link. Individual experts 46 a , 46 b , and 46 c are linked to the selected category 38 by links 47 a , 47 b , and 47 c , respectively, of the “is_expert” type. Individual quick solutions 48 a , 48 b are linked to the selected category 38 by links 49 a , 49 b , respectively, of the “is_solution” type. Individual response templates 50 a , 50 b , and 50 c are linked to the selected category 38 by links 51 a , 51 b , and 51 c , respectively, of the “is_response_template” type. Accordingly, one way to modify the categorization scheme is to modify the links 47 , 49 , or 51 . [0058] Use of the categorization schemes of FIG. 3A in, for example, the manually performed category selection in the business application 28 ( FIG. 2B ) involves the identification of one or more appropriate categories from within a categorization scheme 36 . An exemplary process for manually identifying a selected category 38 is conceptually illustrated in FIG. 3C . An exemplary user interface suitable for manually selecting a category is presented in FIG. 3D . [0059] In the example shown in FIG. 3C (and with reference to FIG. 2B ), the contents of the incoming message 30 is analyzed at 320 by, for example, a content analysis engine that searches the message for key words that match queries defined for the categories in the categorization scheme 36 . In various embodiments, the key word search can be performed either by a human user, or by a programmed computer. Attributes of a category include properties assigned at design-time, and a category's attributes determine whether a category matches the analyzed content of an incoming message. Content analysis may be performed on the textual content of an unstructured incoming email, for example, by performing query-based categorization, example-based classification (using, e.g., either a nearest neighbor, or a support vector machine algorithm on stored previous examples), a combination of both, or other effective method of content analysis. [0060] The content analysis engine 320 uses a categorization scheme 36 to automatically suggest an initial category 325 . This initial category suggestion becomes the current category 330 . If a category is found not to have attributes that match the analyzed content, then no category may be initially suggested. [0061] With the current category 330 initially determined, an interactive auto-suggest cycle begins. Business objects 335 that are linked to the current category 330 may be displayed and suggested to the user, thereby allowing the user to quickly access those business objects that are likely to be relevant to the business process step being performed. The user interface, in this example, displays the selected category to the user at 340 . [0062] With reference to the user's option to choose a different category 38 than the suggested category 39 in FIG. 2B , the user can iterate as needed by selecting a different current category 330 . In turn, the user interface will again display the objects 335 that are linked to the updated current category 530 . In this manner, the user can choose to use the business objects that are linked either to the initially suggested category 325 , or to a manually selected- category. [0063] The foregoing manual selection process can be implemented in a graphical user interface that may be accessed while performing a business process step that involves categorization. An exemplary user interface 350 is illustrated in FIG. 3D . The user interface 350 includes a number of fields that contain drop down list boxes (DDLBs). The user can select a category, for example, from a DDLB 355 labeled “Classification 1.” When selected, the DDLB 355 will display categories that are in a top-level a hierarchical categorization scheme. With reference to FIG. 3A , a top-level category would correspond, for example, to categories at the level of the categories 160 , 170 , 180 . The user can then select a category, for example, from a DDLB 360 labeled “Classification 2.” When selected, the DDLB 360 will display categories that are in a level just below those in the DDLB 355 . With reference to FIG. 3A , these categories would correspond, for example, to categories at the level of the categories 190 , 200 , 210 . The user interface 350 would provide additional levels of categories as needed to permit the user to select any category within the categorization scheme. [0064] The user interface 350 can also provide the functionality that the selection of a category in the DDLB 355 will narrow the displayed alternative categories when the DDLB 360 is selected. This permits the user to quickly work down the categorization scheme from a top level to lower levels without the need to sort through unrelated categories. After the user has selected a category using the user interface 350 , the business process that is being performed can use the business objects that are linked to the selected category. [0065] In some circumstances, a run-time user may select any appropriate linked business objects to perform steps in a business process. In other examples, the run-time user may elect not to use any of the linked business objects, opting instead, for example, to use non-linked business objects, or to use no business objects at all. After all steps that require categorization of the incoming message have been performed, then the run-time use of the coherent categorization ends. [0000] Graphical User Interface (GUI) [0066] With the foregoing introductions to the computing environment and to categorization schemes, this document next describes the GUI that may be used to define categorization schemes. The above-described categorization schemes may be defined in the design-time environment 12 using an exemplary graphical user interface (GUI) 400 shown in FIG. 4 . The user interface 400 includes a categorization area 410 and a linking area 420 . In the design-time environment 12 , a developer can enter, modify, and display information about categories in a categorization scheme. Specifically, the user can create a categorization scheme in the category area 410 , and can enter information associated with each category in the linking area 420 . The user interface 400 further includes one or more tabs such as, for example, the ERMS business process step tab 125 . In other implementations, tabs for other business process steps (not shown) may be included in the user interface 400 . When the user selects a desired business process step tab, then the user interface 400 will display the categorization schemes associated with that business process step in the categorization area 410 . In this example, the ERMS business process step tab 125 is selected. As such, the interaction reason categorization scheme 135 (shown in FIG. 3A ) and the Lego® Org chart categorization scheme 440 (not shown in FIG. 3A ) are displayed in the categorization area 410 . [0067] Using the user interface 400 , a user can arrange categories within the categorization area 410 to have hierarchical relationships within the categorization scheme. The categorization area 410 includes a name column 425 that displays the names of categorization schemes and categories in rows. The user can enter, modify, and display categories in the name column 425 . Adjacent to the name column 425 is a description column 430 that displays a description of the corresponding category in the name column 425 . [0068] Along a top area 435 of the categorization area 410 is a plurality of selectable buttons. Each of these selectable buttons can be used to create or modify categories in the categorization area 410 . The buttons in the top area 435 include a save button 436 , that saves the displayed categorization scheme to a data file or to files in a storage location, such as the stored information repository 22 ( FIG. 1 ). The top area 435 also includes a create sub-node button 437 that inserts a new row below a category that is highlighted (i.e. selected) by the user in the categorization area 410 . A new category may be entered into the categorization scheme by inserting it into the inserted new row, and the new category will be a child category of the highlighted category in the row above it. [0069] For example, and with reference to FIG. 3A , the LEGOLAND® category 160 is linked to three child categories, namely driving directions 210 , entry fee 190 , and events 200 . Each of these categories 190 , 200 , 210 could have been entered as a (child) category into the categorization area 410 by pressing the create sub-node button 437 and entering the category name into a row below the row containing the (parent) LEGOLAND® category 160 . This is one example of how the categorization area 410 may be used to enter categories and sub-categories to create a hierarchical categorization scheme. [0070] The top area 435 also includes other editing buttons 438 for performing cut, copy and paste functions. The editing buttons 438 may be used, for example, to edit and/or move the location of categories within the categorization area 410 . Note that in some implementations, such a move or a copy would cause the text in the description column 430 to move or to copy the corresponding category to the adjacent name column 425 . As such, the text in the description column 430 , as will be described with respect to the linking area 420 , is a property of the corresponding category in the name of column 425 . In addition, the top area 435 may also include a delete button 439 that the user may select to modify the categorization scheme. By selecting the delete button 439 , the user can delete a highlighted row from the categorization scheme. Other features may optionally be incorporated, for example, in the top area 435 . Such optional features may include a button for printing 441 , and an “add to favorites” button 442 , each of which is familiar to web browser users. [0071] In the name column 425 , indicators that precede the name of each categorization scheme and category indicate the hierarchical relationships among categories. For example, bullets in the name column 425 precede the categories 190 , 200 and 210 . These bullets indicate that these categories are terminal categories within the hierarchy of the interaction reason categorization scheme 135 . Within the name column 425 , the Lego® club category 170 , the LEGOLAND® category 160 , and the Lego® products category 180 are preceded by either a right-pointing or downward-pointing triangle marker within the name column 425 . A right-pointing marker, such as the markers that precede the Lego® club category 170 and the Lego® products category 180 in the name column 425 , indicate that no child categories are displayed. A downward-pointing marker, such as the one that precedes the LEGOLAND® category 160 in the name column 425 , indicates that any linked child categories are displayed in the rows immediately beneath that parent category. If a user clicks on the downward-pointing marker, then the marker will change state to a right-pointing marker, and no child categories will be displayed. Similarly, if a user clicks on the right-pointing marker, then the marker will change state to a downward-pointing marker, and existing child categories (if any) will be displayed. In this example, the LEGOLAND® category 160 has one level of child categories which are all terminal categories. Other implementations are also possible. For example, multiple levels of categories may be defined within a categorization scheme. Alternatively, a flat structure may be defined for a categorization scheme such that there are no child categories. [0072] Similar to categories, categorization schemes are also preceded by indicators. In the name column 425 , two categorization schemes, namely, the interaction reason categorization scheme 135 , and the Lego® Org Chart categorization scheme 440 , are displayed with preceding indicators. In this example, a downward-pointing arrow precedes the interaction reason categorization scheme 135 . Accordingly, the categories below the interaction reason categorization scheme 135 are displayed. In contrast, the Lego® Org Chart categorization scheme 440 is preceded by a right-pointing marker in the name column 425 . As such, no categories under that categorization scheme are displayed in the name column 45 . [0073] The number of categories displayed in the categorization area 410 is limited by the number of rows displayed. If the number of categories and categorization schemes to be displayed exceeds the number of displayable rows in the categorization area 410 , then non-displayed rows can be viewed by scrolling the displayed rows up or down using the scroll buttons 445 . In this way, the user can control which rows are displayed in the categorization area 410 . [0074] Accordingly, the categorization area 410 in the user interface 400 serves as a tool to enter, modify, and display categorization schemes in the design-time environment 12 . As can be appreciated, the categorization area 410 is used to define various links that structure the hierarchical relationships within the categorization scheme. With reference to FIG. 3A , the categorization area 410 is used to define the links 155 , 165 , 175 between the categorization scheme 135 and the categories- 160 , 170 , 180 . Furthermore, the categorization area 410 is used to define the links 185 , 195 , 205 between the parent category 160 and the child categories 190 , 200 , 210 . However, the categorization area 410 in this example does not (by itself) define links between business process steps and categorization schemes, or between categories and business objects. In this example, those links are defined in conjunction with the linking area 420 . [0075] In the linking area 420 , a number of tabs are provided to display various fields related to a user-highlighted category in the categorization area 410 . In this example, the driving direction category 210 is the highlighted category in the categorization area 410 . The tabbed view sets in the linking area 420 include the details viewset tab 450 , the query viewset tab 455 , the example documents viewset tab 460 , the standard responses viewset tab 465 , and the knowledge entities viewset tab 470 . Each of these viewset tabs 450470 in the linking area 420 will now be described in turn. [0076] The details viewset tab 450 is selected in FIG. 4 . The details viewset tab 450 includes a general area 472 for entering information about a selected category. In this example, the user interface 400 is used to enter and modify information about the selected driving directions category 210 . One field in the details viewset tab 450 is used to enter and modify the category name 475 , which, in this case, is “driving directions.” Another field is the category ID field 476 . The category ID is a language-independent internal (not displayed) identifier to facilitate matching. In contrast to the category ID, the category's name is a language-dependent label that is displayed on the user interface in association with the corresponding category. A parent category field 477 displays the name of the parent category, which, in this case, is “LEGOLAND®” corresponding to the LEGOLAND® category 160 . [0077] A description field 479 permits the user to enter a textual description of the category. This provides a description of the category's semantic meaning in addition to the meaning expressed by the “name” (or label). The textual description in the description field 479 is displayed in the description column 430 in the categorization area 410 , and specifically the highlighted row. Other auxiliary information, such as a creation date, identity of the author (i.e. “created by”), a last modified date, a last modified by, and a status field illustrate the exemplary configuration of the linking area 420 . Each of these fields may optionally be populated to further define the characteristics of the selected driving directions category 210 . For example, the parent category field 477 may be automatically populated based on the parent-child relationship already displayed in the categorization area 410 between the (parent) LEGOLAND® category 160 and the (child) driving directions category 210 . [0078] In FIGS. 5A-5B , the query viewset tab 455 is selected. In this example, the user interface 400 is used to define a query for the highlighted category. The defined query can be evaluated to determine if the content of an e-mail corresponds to that category. [0079] In the query viewset tab 455 , two rows of query criteria are shown. Elements for defining a query may be entered into columnar fields defined in a first row 510 and a second row 520 . In the first row 510 , a match column 515 includes a leading “if” statement. In the second row 520 , the match column 515 includes a user-selectable drop-down list box (DDLB) into which the user can select various conditional conjunctions such as, for example, “and,” “or,” and “nor.” The conjunction provides the logical operation that connects queries in the rows 510 , 520 . For example, if, in the run-time environment 14 , the row query 510 evaluates as “true,” and if the row query 520 evaluates as “false,” and if the conjunction 515 in the row 520 is “or,” then the complete query will evaluate as “true.” However, if the conjunction 515 in the row 520 is “and,” then the complete query will evaluate as “false.” If the complete query for a category evaluates as “true”, then the content of the e-mail “corresponds” to that category. On the other hand, if the complete query evaluates as “false”, then the content does not correspond to that category. [0080] The row queries for rows 510 , 520 are defined by columnar fields in each row. An attributes column 525 provides a DDLB through which the user can identify attributes that are to be evaluated using the query defined in that row. For example, if the query of an e-mail relates to information contained in both the subject line and the body of the email, each row query can evaluate the content of the subject line, the body, or both. In this example, the row 510 will evaluate “subject and body”, while the row 520 query evaluates only the “subject”. [0081] An operator column 530 provides a DDLB through which the user can define the relational operator to be used to evaluate the query in that row. For example, the operator column 530 may include operators such as equality, inequality, greater than, less than, sounds like, or includes. A value column 535 provides a field in each of rows 510 , 520 into which the user can enter values for each row query. If the attribute 525 and the value 535 in a row query have the relationship of the selected operator 530 , then that particular row will evaluate as “true.” If the attribute 525 and the value 535 do not have the relationship of the selected operator 530 for a particular row, then that particular row will evaluate as “false.” Each row is connected to the previous row or to the subsequent row through a logical match operator 515 , such as “and,” “or,” and “nor.” Although only two rows 510 , 520 are shown in this example, other rows may be entered using the scroll keys 540 . A case column 545 provides a check box which, when checked, makes the query in that row case sensitive. [0082] An alternative example for displaying the linking area 420 when the query viewset tab 455 is selected is shown in FIG. 5B . In this example, the scroll buttons 540 (of FIG. 5A ) have been replaced with next and previous buttons 541 , 542 . In this example, one row of a query can be entered using the match 515 , attribute 525 , operator 530 , value 535 , and case sensitive 545 fields. [0083] In FIG. 6 , the example documents viewset tab 460 is selected. In this example, the user interface 400 is used to enter and modify example documents. In this context, example documents are prototypical documents for the given category. A document may be determined to be prototypical based upon historical usage statistics with regard to a particular category. [0084] In FIG. 7 , the standard responses viewset tab 465 is selected, and the linking area 420 includes a response template area 705 and a response preview area 710 . In this example, the user interface 400 is used to enter and modify links between a selected category in the categorization area 410 and e-mail response templates 50 in the response template area 705 . In this example, the second row 715 of the response template area 705 is highlighted, and the response preview window 710 displays the text associated with the response template 50 that contains driving directions to LEGOLAND® California. [0085] In the response template area 705 , a first column 720 includes selectable boxes that serve as buttons for getting additional help screens. Specifically, selecting one of the buttons in the left margin of each row causes a value-help screen to pop-up. Once a value-help screen is popped-up, the user can perform searches, among other auxiliary functions. The pop-up is depicted in FIG. 9B . [0086] A form name column 725 is used to enter, modify, and display the name of the response template 50 in each row. The user can delete a row by first selecting it and then selecting the delete entry button 730 . The user can add a new row by selecting the add entry button 735 . A description column 740 provides for entry, modification, and display of a description of the corresponding response template 50 in a selected row. A language column 745 provides an indication of the language used in the response template 50 . In this example, all four rows indicate that the four associated response templates 50 are in the English language. Although four rows of response templates are shown in this example, additional rows, if any, can be displayed by scrolling using the scroll keys 750 . Further details about each response template are illustrated by columns 755 , 760 , 765 and 770 , which indicate, respectively, who created the template, when the template was created, what format the template is in, and the text type that is used for the template. [0087] In the response preview window 710 , the user can review, enter, and modify the text of the response template 50 linked to the highlighted response template 50 form name column 725 . In this example, the selected response template 50 is “Directions-LEGOLAND® California” 715 . [0088] In FIG. 8 , the knowledge entities viewset tab 470 is selected. In this example, user interface 400 is used to define links between the selected category 210 in the categorization area 410 and business objects, namely experts 46 and quick solutions 48 , in the linking area 420 . In alternative implementations, the linking area 420 could also provide a separate experts viewset tab (not shown) for defining links between a selected category and experts 46 . When the knowledge entities tab 470 is selected, the linking area 420 displays a row 810 for linking business objects to a selected category, and a response preview area 820 for entering, modifying, and displaying a response template for use with the business object displayed in the row 810 . [0089] In this example, the selected driving directions category 210 can be linked to a document (i.e. a quick solution 48 ) stored in a knowledge base by entering the name (e.g., filename) of the document in a title column 825 in the row 810 . In a “KB Name” column 830 , the user can enter the name of a knowledge base in which the document identified in the title column 825 can be found. Alternatively, the KB Name column 830 may be automatically filled in when the document in the title column 825 is entered. Although only one row, namely the row 810 , is shown in this example, a user can manipulate the scroll keys 840 to display other rows, if any. The user may also link additional documents to the driving directions category 210 by selecting the add entry button 845 . The user may also select the delete entry button 850 to delete a link between a document and the driving directions category 210 . [0090] The row 810 provides additional information about the selected document identified in the title column 825 . In this example, the additional information includes the language in which the document is written, the identity of the person who created the document, the date the document was created, the identity of the person who last changed the document, and the day on which they changed the document. The additional information about the selected document in column 825 may be entered either manually by the user, or automatically filled-in when the user selects a document. The additional information may be associated with the document in, for example, a database table defined in a knowledge base in which the document is stored. [0091] In the response preview area 820 , text for use in a response email may be prepared. The text of the response is associated with the document displayed in the row 810 . For example, if a document is entered in the row 810 , then when that document is attached to an email in the run-time environment 14 , the associated text in the response preview area 820 may automatically be inserted into the reply email. In some examples, each document linked to the selected driving direction category 210 may have a different response text that is displayed in the preview area 820 . For example, if the user selects the add entry button 845 and enters a second document in the title column 825 , then the user may use the response preview window 820 to enter or modify a second response text that is associated with the second document. [0092] Accordingly, FIGS. 4-8 illustrate examples in which the linking area 420 is used to directly enter, modify, and display information about categories in the categorization area 410 . In FIGS. 9A-9B , the user interface 400 incorporates a search feature to enable the user to search for stored information within the enterprise computing system 10 . In one example, the search features may be used to search for standard responses. [0093] In FIG. 9A , the user interface 400 includes the categorization area 410 , the linking area 420 (with the detailed viewset tab 450 selected) and an advanced search window 910 . The user opens the advanced search window 910 by selecting the open advanced search button 490 (shown in FIG. 4 ). The open advanced search button 490 automatically changes to a close advanced search button 920 while the advanced search window 910 is open. If the user selects the close advanced search button 920 , then the advanced search window 910 would be closed, and the user interface 400 would return to the configuration of FIG. 4 . [0094] In FIG. 9B , the user can search for standard responses using the “Smart Forms” pop-up screen. [0095] The foregoing examples of FIGS. 4-9 illustrate functionality of the user interface 400 when a category in the categorization area 410 is selected. In FIG. 10 , a categorization scheme is selected instead of a category. In this example, the interaction reason categorization scheme 135 is selected. When a categorization scheme is selected in the categorization area 410 , the linking area 420 displays a details viewset tab 450 . In this example, the details viewset tab 450 includes a general area 1005 and an application area 1010 . The application area 1010 is only displayed when a categorization scheme is selected in the categorization area 410 . With reference to FIG. 4 , the general area 1005 provides the same information associating functions for a selected categorization scheme as the general area 472 ( FIG. 4 ) provides for a selected category. [0096] In the application area 1010 , the interaction reason categorization scheme 135 is associated with several business process steps (also referred to as application areas). The associations are indicated by a check-marked box adjacent to the name of an available application area. In this example, the checked application areas include the interaction record business process step 120 , more responses 1015 , knowledge search 1020 , and rules engines 1025 . These associations have the effect that when any of these applications 120 , 1015 , 1020 , 1025 are executed to perform their respective business process steps, the interaction reason categorization scheme 135 (or its current result) can be used. With reference to FIG. 3A , the interaction reason categorization scheme 135 is linked to the interaction record business process step 120 by the link 130 . The link 130 is established when the user checks the box adjacent to the interaction record categorization label within the application area 1010 . [0097] In accordance with the foregoing discussion, the above-described user interface 400 can be used in the design-time environment 12 to create categorization schemes for use in the run-time environment 14 . An exemplary procedure for using the user interface 400 to efficiently define a categorization scheme is presented in FIG. 11 . The exemplary method will be described with reference to previous figures. Other implementations of the method may use different steps, or be performed in a different order to achieve similar results. The example of FIG. 11 merely illustrates one representative implementation of the invention. However, the user interface 400 is capable of being used in many different orders and combinations of steps. [0098] A flow chart 1100 of the design-time procedure to create a categorization scheme starts at 1105 . The user selects a business process tab (e.g., ERMS tab 125 in FIG. 4 ). At 1115 , the user enters a categorization scheme into the name column 425 of the categorization area 410 ( FIG. 4 ). With the categorization scheme highlighted, the user links at 1120 the categorization scheme to one or more application areas, the application area 1010 ( FIG. 10 ). At 1125 , the user selects a categorization scheme in the categorization area 410 ( FIG. 4 ). At 1130 , the user enters a category under the selected categorization scheme by, for example, selecting the create sub-node button 437 and entering a category into the name column 425 of the categorization area 410 ( FIG. 4 ). At 1135 , the user enters information about the selected category into general area 472 ( FIG. 4 ). At 1140 , the user defines a query under the query tab 455 that, if evaluated as true in the run-time environment 14 , causes the associated category to be selected. At 1145 , the user links a business object to the selected category by, for example, identifying a document for attachment using the row 810 in the linking area 420 ( FIG. 8 ). [0099] The types of business objects that may be linked to the selected category include: experts 46 in a business partners tabstrip (not shown); quick solutions 48 in the knowledge entities view set tab 470 ( FIG. 8 ); and, response templates 50 in the standard responses view set tab 465 ( FIG. 7 ). As one of skill in the art will appreciate, viewset tabs on the user interface 400 may be added or modified to accommodate new types and uses of business objects. [0100] At 1150 , if the user wishes to add another business object to the selected category, the user can repeat the step at 1145 by, for example, selecting the add entry button 845 ( FIG. 8 ). As another example at 1150 , the user can select the standard responses tab 465 and add or modify response templates (which are a type of business object) using the add entry button 735 , or by editing the response preview area 710 , respectively ( FIG. 7 ). If the user does not wish to add more business objects, then at 1155 , the user can choose to add another category under the current categorization scheme by looping back to step at 1130 . If no more categories need to be added, then the categorization creation process ends at 1160 . [0101] The foregoing exemplary method illustrates the entry of categories and the linking of business objects to create a categorization scheme. As can be appreciated, the method can be adapted as needed to use the user interface 400 to modify and to display the categorization scheme that has been entered. It can further be appreciated that the method can be used to enter, modify, and display more than one categorization scheme. Moreover, the method can be adapted so that the user interface 400 can be used to maintain existing categorization schemes over time. For example, the user interface 400 can be used to adapt the categories, linked business objects, and linked application areas to meet changing demands of the business processes as they evolve in the run-time environment 14 . [0102] Other Implementations [0103] Although various examples of the user interface have been described, other implementations are also within the scope of the invention. For example, the categorization area 410 of FIG. 4 may be used to enter and modify a categorization scheme without a corresponding linking area 420 . [0104] Although FIG. 1 illustrates the enterprise computing system 10 as having one terminal 24 in the design-time environment 12 and another terminal 26 in the run-time environment 14 , the two terminals 24 , 26 may represent a single physical computer terminal or computer work station. Furthermore, the design-time environment 12 may include any number of terminals/work stations that can be used in combination to create run-time modules that use coherent categorization schemes. Similarly, the run-time environment 14 may include any number of terminals/work stations that can be used to perform business processes by executing run-time modules. As used in this document, terminals 24 , 26 represent physical input/output devices for displaying and entering information in the enterprise computing system 10 . [0105] Other implementations may use configurations of the user interface 400 other than those provided in the above-described implementations. In FIG. 4 , for example, the description text in the description column 430 may be provided in the name column 425 instead of being provided in an adjacent column. [0106] As another exemplary configuration, the functionality provided by the create sub-node button 437 ( FIG. 4 ), namely, creating a child category under a selected category, may be implemented using “promote” and “demote” buttons in the top area 435 . Promote and demote buttons could, for example, incrementally shift the level of a selected category within the categorization scheme. Accordingly, links to the adjacent rows above and below the selected category could be adjusted accordingly to match the hierarchy's visual representation in the categorization area 410 . Furthermore, “move up” and “move down” buttons could also be provided to further simplify the creation of a hierarchical categorization scheme by giving the developer the ability to move a selected item and re-position it within the name column 425 . [0107] The invention can also be implemented with digital electronic circuitry, or with computer hardware, firmware, software, or in combinations of them. Apparatus of the invention can be implemented in a computer program product tangibly embodied in a machine-readable storage device for execution by a programmable processor; and method steps of the invention can be performed by a programmable processor executing a program of instructions to perform functions of the invention by operating on input data and generating output. The invention can be implemented advantageously in one or more computer programs that are executable on a programmable system including at least one programmable processor coupled to receive data and instructions from, and to transmit data and instructions to, a data storage system, at least one input device, and at least one output device. Each computer program can be implemented in a high-level procedural or object-oriented programming language, or in assembly or machine language if desired; and in any case, the language can be a compiled or interpreted language. Suitable processors include, by way of example, both general and special purpose microprocessors. Generally, a processor will receive instructions and data from a read-only memory and/or a random access memory. The essential elements of a computer are a processor for executing instructions and a memory. Generally, a computer will include one or more mass storage devices for storing data files; such devices include magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; and optical disks. Storage devices suitable for tangibly embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, such as EPROM, EEPROM, and flash memory devices; magnetic disks such as internal hard disks and removable disks; magneto-optical disks; and CD-ROM disks. Any of the foregoing can be supplemented by, or incorporated in, ASICs (application-specific integrated circuits). [0108] The invention has been described in terms of particular examples. Other examples are within the scope of the following claims.	A graphical user interface (GUI) tool for maintaining categorization schemes includes a categorization area that displays user-input fields which may be used to define a number of categories and a number of links that form a categorization scheme. The categorization scheme is organized to enable the computer-executed process to categorize the data. The categorization causes the selection of categories that correspond to the data. The selection is made by making a category determination beginning at the top level and proceeding to the children of categories that correspond to the data.	8
This invention relates to a method and apparatus for repair of so-called "dry wall" interior building panels and, more particularly, to a repair kit and constituents thereof that facilitate the repair of damage to "dry wall" interior building panels. Because of the escalating expense that has been characteristically attendant the construction of lath base, plaster surfaced interior building wall construction, the years since World War II have seen a progressively increasing utilization and reliance upon so-called "dry wall" interior building panels for interior wall and space definition both in private dwellings and in commercial installations. Such "dry wall" construction conventionally employs 4×8 gypsum board panels, usually called "sheetrock" or the like, having a gypsum core disposed intermediate cardboard sheeting and with the joints between adjacent panels masked by an overlaying perforated paper tape submerged in a spackling type compound. While the impetus behind the shift to such "dry wall" construction has been realistically founded upon the markedly reduced costs of installation thereof, one deleterious consequence has been the provision of an interior wall structure that is particularly subject to damage because of its inherent lack of resistance to impact forces or the like. The susceptibility to damage of such "dry wall" interior construction has been accompanied by a concomitant and continually escalating cost of professional repair of such impact damaged "dry wall" panels and with a concomitant demand for facilitated home owner type repair thereof. Such repair conventionally involves a redefinition of the damaged area to provide straight marginal edges therefore, substitution of a complementally dimensioned new wall section for the redefined damaged area, and a retaping and respackling of the new interfacially abutting marginal edges to provide a smooth and unblemished wall surface preparatory to repainting thereof. While such broad repair steps are conventional in nature and are basically necessitated by the character of the building materials employed, considerable difficulties have been encountered through the use of clips or other noncontinuous elements in properly positioning the replacement panel section vis-a-vis the marginal defining edges of the redefined damaged area so as to assure coplanar alignment thereof and appropriate coplanar positioning of the interfacially abutting marginal edge portions thereof so as to facilitate tape application thereto and subsequent spackling and finishing operations. This invention may be broadly described as an improved repair kit assembly to facilitate home owner repair of damaged "dry wall" panels. In its broader aspects, it includes provision of a selectively constituted repair strip, severable to appropriate length at the point of use, that is operative to effectively properly position the marginal edges of the redefined opening and of a replacement panel segment to effect coplanar positioning of the replacement panel relative to the wall and thus readily permit application of the perforated tape and subsequent spackling over the abutting marginal edges to provide a smooth and unbroken repaired wall surface. In its more narrow aspects, the subject invention includes the provision of a selectively constituted repair strip having a relatively rigid back portion adapted to be disposed behind the marginal edges of the redefined opening and the replacement panel to position the latter in coplanar relation with the former and an integral extending center portion adapted to extend outwardly intermediate the abutting marginal edges of the redefined opening of the wall panel and the replacement panel and to be deformed into adhesively secured relation with the adjacent coplanar outer surfaces thereof. Among the advantages of the subject invention is the provision of an improved method for effecting the repair of damaged "dry wall" interior building panels and the provision of a simple and inexpensive repair kit that includes a selectively constituted repair strip that facilitates home owner repair of "dry wall" panels. The primary object of this invention is the provision of an improved method and device for effecting repair of damaged "dry wall" type building panels. A further object of this invention is the provision of an improved method and device for repair of "dry wall" building panels that can be compatably finished by conventional tape and spackle techniques. Still another object of this invention is the provision of an improved device in the form of a selectively constituted repair strip for effecting repair of damaged "dry wall" type building panels. Other objects and advantages of the subject invention will become apparent from review of the following portions of this specification and from the appended drawings which illustrate, in accord with the mandate of the patent statutes, a presently preferred embodiment incorporating the principles of this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an oblique view of a "dry wall" repair strip incorporating the principles of this invention. FIG. 2 schematically illustrates a damaged area in a "dry wall" building panel and the initial steps involved in the repair thereof. FIGS. 3A and 3B are generalized sectional views of the installation steps for the repair strip shown in FIG. 1. FIG. 4 is an enlarged schematic view of the positioning protrusions included in the repair strip and shown in FIG. 1. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring initially to FIG. 1 of the drawings, there is provided an improved "dry wall" panel repair device, generally designated 10, in the form of an elongate strip of compositely constituted material having a cross-sectional configuration in the nature of an inverted "T". The base portion thereof, generally designated 12, is formed of an elongate strip of relatively hard sheet metal or the like, preferably relatively hard temper, i.e. H16 or H18 light gauge aluminum sheet, suitably 007-015 inches thick, or a heavy gauge hard rolled aluminum foil, suitably 004-006 inches thick, having its elongate marginal edges 14 folded back, as at 16, to form a relatively rigid double thickness backing strip. The rigidity of said base portion 12 may be determined entirely by the thickness and temper of the metal employed or it may be supplemented by incorporation of a rigid core material as indicated by the dotted lines 18. It is contemplated that the repair kit will include several elongate repair strips 10 of varying transverse dimension and base portion rigidity for selective use thereof in accord with the size and location of the area to be repaired. The center or perpendicularly extending portion of the strip 10, generally designated 22, is formed of a pair of separable strips of tapes 24 and 26, suitably of heavy paper or of resinous film material. The remote marginal edge portions 28 and 30 of the tape strips 24 and 26 respectively are firmly anchored intermediate the folded back portions 16 of the base 12. If desired the center portion 22 of the strip 10 may be formed of a single strip of tape material having its intermediate body portion folded back upon itself in the nature of an inverted "T" and with the base portion thereof disposed within the folded back portions 16 of the base 12 of the metal backing where it is not only firmly anchored therebetween but also serves to supplement the rigidity of such base portion 12. The outwardly extending tape strips 24 and 26 are coated on their outwardly facing surfaces with a pressure sensitive contact adhesive coating 32 covered by a removable paper strip 34. As best shown in FIG. 3, the exposed marginal edges of the tapes 24 and 26 are tapered as at 36 to facilitate, as will become later more apparent, the feathering of the joint adjacent the abutting marginal edges of the redefined damaged wall area and the replacement panel section. As best shown in FIGS. 1 and 4, the base portion 12 of the strip 10 includes a plurality of selectively located jagged protrusions 40 which may be constituted of discrete tack-like members but which are preferably formed by punching small holes 42 in the assembled base portion 12 as shown in FIG. 4. The method of repair of a damaged "dry wall" or "sheet rock" panel is schematically shown in FIGS. 2, 3A and 3B. By way of example, the damaged area may be considered as an irregular hole indicated by the dotted line 46 on FIG. 2. First, the damaged area is enlarged to define a straight edged aperture, such as a square or rectangle 48. While such redefined damaged area is preferably of rectilinear shape, curved marginal edges can be accommodated, where necessary, by cutting appropriately located sectors in the base portion 12 of the strip. A replacement or patch panel 50 of perimetric dimension shaped sized to closely fit within the redefined damaged area is then prepared. Appropriate segments of the repair strip 10 of a length to be disposed within the defining marginal edges of the redefined damaged area are then severed from the elongate supply thereof. One of such strips is then placed along the marginal edge of the redefined hole, as illustrated in FIG. 3A, with one side of the base portion 12 thereof disposed in interfacial engagement with the back surface 52 of the existing wall panel 54, and with the protrusions 40 thereon pressed firmly into the cardboard or paper facing of such panel. While maintained in such compressive engagement, the paper covering for the strip 24 is removed and the strip 24 is pressed into adhesively secured relation to the edge and outer surface of the panel as shown at 56. Such operation is repeated for each of the marginal edges of the redefined damage area to thereby provide a relatively rigid perimetric shelf or shoulder, compositely constituted by the remaining portions 58 of the bases 12 of the strips, disposed at the back of the redefined damage area. The replacement of patch panel 50 is then placed into the opening, gently pressed against the exposed portions 58 of the base 12 of the wall mounted strips and secured in position by folding back the tapes 26 into adhesively secured relation with the edge and outer surface of the patch as shown at 60 in FIG. 3B. The joint between the mounted replacement panel 50 and the wall may now be finished by conventional tape application and spackling.	This invention is directed to method and apparatus for repairing damaged dry wall building panels and includes a selectively constituted repair strip operative to properly position the marginal edges of a redefined opening and replacement panel segment to effect co-planar positioning of the latter relative to undamaged wall sections.	4
CROSS-REFERENCE TO RELATED APPLICATION This application claims benefit of copending U.S. provisional application No. 60/286,699, filed Apr. 26, 2001, entitled “HIGH PERCENTAGE RECOVERY LAUNDRY WASH WATER RECYCLE SYSTEM”, the disclosure of which is incorporated in its entirety herein by reference. FIELD OF THE INVENTION The present invention relates to apparatus for wastewater recovery. More particularly, a preferred embodiment of the present invention provides an apparatus and method of recovering wastewater from laundry operations. BACKGROUND OF THE INVENTION Wastewater recovery from laundry operations has become a developed area of industry as water costs increase and the costs of municipality water treatment increases. The advantages of recovery of the wastewater from the laundering process are both economic and environmentally responsible. The user reduces the net demands on the valuable commodity of drinking water, reduces the requirements for sewer disposal, recovers the heat from the wastewater stream and can recover some of the chemicals used in the washing process. Indirect advantages can include decreased demand on equipment needed to provide water heating needs as well as water softening needs in laundry environments. This can extend the life of the equipment, reduce maintenance costs, and in situations where the operation is new, reduce the capacity needs of this equipment, reducing capital expenditures in this area. In recent years, attention has been focused on methods to recover wastewater from industrial applications. Particular attention has been focused on the wastewater from commercial laundries. Typical commercial laundries use extremely high amounts of water to complete the laundering process. Other systems use methods to recover portions of the rinse water and reuse it for the wash cycle. Other art has focused on methods to capture all the wastewater from the washing machines and use a process of nano-filtration or reverse osmosis filtration to produce adequate water for reuse. A deficiency of both of these systems is the net percentage of wastewater the processes can hope to recover. Through the recovery of the rinse water only, a system can recycle, at best, 25% of the total water used in the laundering process. In addition, this recovery method is not used for continuous batch style washers due to the fact that the rinse water is never released into the waste stream. Likewise, a recycle process which employs nano-filtration, reverse osmosis or other type of membrane or ceramic filtration can not exceed about 60% total wastewater recovery due to the filters requirement of continuous flushing. In addition, these types of filtration process can cause additional problems for consumers who have restrictions on the wastewater quality imposed upon them by the local waste water treatment works and the Environmental Protection Agency. These types of filters generally send the flushing water to drain. In these filters concentrate the contaminants in the actual wastewater discharged to drain. BACKGROUND OF THE PRIOR ART While there are several companies promoting products or systems that recycle laundry wastewater, each has limits in its ability to recycle an optimum percentage of wastewater. Discussed below are several available types of systems that offer different products that provide a representation of products available in the marketplace. Air Backflush Water Filtration System: In conventional laundry environments, front-loading washing machines has three basic cycles—initial flush, wash, and rinse cycles. The initial flush pulls the large solids out of the laundry and discharges it. The wash cycle has injected chemicals such as bleach and detergent that, combined with hot water, break down the soiled garments and remove the majority of dirt and solids embedded in the laundry. After the wash cycle water is discharged to the drain, the final rinse cycle tends to be the cleanest wastewater, having minimal suspended solids and having a large concentration of chemicals. The air backflush system takes in the final rinse water and filters it through a series of filter bag elements that accumulate the solids as the water is pushed through the system. A pressure differential gauge monitors the accumulation and as the pressure increases between the inlet and outlet of the water filter, the system automatically initiates an air-assisted backflush that pushes the solids through the top of the filter element and through a separate drain discharge. This type of system is available from Kemco Systems. While the company claims water reductions of up to 50%, most systems of this type will be limited to about 30% or less water usage reductions. There are also some energy savings since this “water reuse” system will provide about 30% of new water at temperatures between about 80 and 90 degrees Fahrenheit. This represents an energy savings of about 15%. Dissolved Air Flotation (“DAF”) System: DAF systems are commonly used in discharge environments where there are very high levels of suspended solids, oil and grease (FOG's), BOD's, and COD's. DAF systems function as follows: Discharge water is sent through a large solids filtration system. Filtered water is then sent to a large equalization tank (8 hrs of discharge). Because of the excessive volatility of the composition of the discharge water, large tanks with internal mixers help keep the water from having high volatility, which helps with the consistency of chemical injections. From the equalization tank, water is then pumped into the DAF Unit. Certain chemical polymers, flocculent, clay media, and other similar chemicals are injected into the process water to cause the solids to adhere and solidify, then coagulate and flocculate. Air is then injected into the process water causing the solids to rise to the top of the DAF unit. As the solids accumulate, a skimmer pushes the mud-like solids into a large holding tank. This sludge is then usually run through a filter press or de-watering unit until the solid is a black powdery material that is sent to a landfill. DAF units are normally used as a pretreatment before discharging to sewer. However, these units are also sold as solutions to water recycling, as well. The DAF system suffers from several drawbacks. Because of the polymers and other chemicals injected into this process, there is a very high build-up of dissolved solids. This high TDS recycled water can only be reused in the wash cycle which represents about 33% reuse and there is very little energy savings. Also, there is a very high chemical cost as well as a very high equipment cost. Additionally, the DAF unit takes up a very large amount of space and can be labor intensive. This type of system is available from Kemco Systems. Ceramic or Membrane Systems: Ceramic or membrane system provide the cleanest and most potable water from recycling available in the marketplace. These systems, also referred to as Reverse Osmosis (R/O) systems, are usually added on to systems that already provide a proper pre-filtration or pre-treatment process. The R/O process requires process water to be filtered down to about 5 microns or less before beginning its filtration or the membrane can become fouled or clogged up quickly. The nano-filtration process uses high levels of pressure to push process water through the pores of very small openings in filter elements. The process removes the smallest levels of suspended solids as well as the majority of any dissolved solids in the water. This final “permeate” water is usually considered drinking water quality. Reverse osmosis recycling, while very effective, is also expensive. R/O equipment by itself is very costly; however, this unit is attached to the end of the normal filtration process virtually doubling the final cost. Because of the need for very high levels of pressure, the energy cost to produce this high pressure provides an additional negative due to added operational costs. An additional disadvantage is that the RIO process, while removing the highest level of solids in the process water, loses about 30-50% of its water in the process. At a 60% recycle rate, high operational costs, large footprint, and very high equipment costs, this application is not necessary to recycle laundry wash water; this is a drinking water application only. This type of system is available from Kemco Systems. Rinse Water Reuse: The rinse water reuse system is very similar to other systems except that the rinse water reuse system only reuses selected cycles in the rinse process, providing an even less attractive recycle percentage. This system process utilizes a lint vibration system only, which will usually only provide a reduction in suspended solids to about 175 microns. The recycle percent averages about 25% and heat recovery about 10%. This type of system is available from Thermal Engineering of Arizona. Heat Recovery or Reclamation System: Heat recovery systems claim to recycle discharge water; however, the “reuse” process is short-lived. The process begins with a sump pump pulling discharge water from the collection pit and through a lint vibration or lint shaker system. Once the large solids are removed, the process water goes to a collection tank waiting for incoming water needs. As new city water coming through the heat exchange unit, it runs through small coils within the unit. The process water goes through the outside chamber and the preheated process water “heats” or transfers its heat to the new city water. While effective in reducing energy costs, most units do not transfer more than about 20-25 degrees Fahrenheit of heat. Cost benefit effectiveness is rather low due to high equipment costs and low energy savings. Discharge water is used to only heat hot water. Since this represents about 33% of total water, the system runs the city water through an additional time or two, each time increasing the temperature. Running the water through this many times can increase the reheat temperature up to 100 to 110 degrees Fahrenheit. However, there are added equipment costs to utilize this new process. While effective in reducing energy costs, there is no recycle process, so the only savings is in the energy. With high equipment and maintenance costs, the savings are difficult to justify except at an environmental standpoint. This type of system is available from Thermal Engineering of Arizona. Ozone Laundry System: Ozone, or activated air, is a form of oxygen created when an electrical charge is passed through the air. It functions as an oxidizer as well as a disinfectant. Ozone is used in many industries and is very effective for what it was developed for, i.e., a disinfectant. Ozone is used in laundry operations as a means to reduce or eliminate hot water use and to drastically reduce chemical usage. Injecting high doses of ozone into the wash cycle takes the place of hot water as a disinfectant and can reduce the chemical needs as well. In addition, with less chemical needs there is less cycles and less water needed to wash clothes. These claims caused great excitement in the laundry industry in the late 1980′s as companies were trying to save energy and reduce costs. However, in actuality, the process was ineffective as well as damaging to equipment. Without hot water, the garments were coming out of the washing machine gray and wrinkled. Without the chemicals needed, the garments continued to come out stained. And finally, over long periods of time (12-18 months) equipment such as piping and washer parts began to crack or become brittle from the high level of oxidation provided by ozone. The claims of 90% less hot water, 30% reduction in water and sewer costs, and 40% less chemicals were unfounded. Most of these systems are not sold currently—they are installed for free and the companies split the savings—a process very difficult to access and fairly inaccurate. This type of system is available from EnviroCleanse. Laundry Recycle System: Vehicle wash water recycling system takes laundry wastewater, passes it through a cyclone separator, a series of lint screens, oil absorption pillows, large open containers of river rock, and then through pressurized vessels of activated carbon and hydrocarbon before the water in considered recycled. It also uses ozone as a disinfectant. The system is designed to run by gravity requiring appreciably more equipment than pressurized systems. All products (other than pressure vessels) are open container causing a high susceptibility to bacteria and viruses in the water. Because there is no “backwashing” capabilities, the system is very labor intensive to keep equipment clean. While ozone can disinfect, it is injected only in limited locations, causing the remaining system to be completely exposed to infectious diseases and bacteria. In addition, there is limited suspended solids removal causing small lint particles to pass through the open rock beds and into the final water. This leaves the final recycled water looking cloudy and discolored. Finally, these units take up tremendous amounts of space and are extremely difficult and time consuming to install and maintain. This system is available from World-Wide Water Recycling. U.S. Pat. No. 6,299,779B1, issued to Pattee, discloses a method for re-use of laundry wash water using a system of separators, filters and ozonation. The ozonation is carried out in pipes that connect various open tanks or beds. A problem with such a system, as well as several other systems discussed hereinabove, is that bacteria are not effectively removed. Open beds or tanks promote growth of bacteria, such as fecal coliform, part of human waste. These bacteria can also move into the closed, pressurized vessels and infect the activated carbon and hydrocarbon tanks. It has become an increasingly prominent concern of commercial laundry facilities to remove bacteria effectively to assure the user or wearer of the laundered item of a clean garment or article. It would be desirable to have a wash water recycling system that addresses the deficiencies in the prior art and provides an efficient recycling system that provides recycled water sufficiently clean to be reused in the wash facility. Such a system would preferably have closed filtration vessels to reduce bacteria growth as well as an effective disinfectant system to remove bacteria present in the wash water entering the recycle system. In addition, while ozone is a good disinfectant, there are certain small viruses that can escape ozone disinfection. Differing variations of radiation at the conclusion of the recycle process provide a final step to complete disinfection as well as a means to neutralize any remaining ozone from escaping the recycle system and possible transfer to washing equipment. SUMMARY OF THE INVENTION Generally described, the present invention provides in a preferred embodiment a system which transfers waste wash water from laundry machines to a trough. The wash water is then pumped to a process tank. This water is subjected to ozone which removes odor and controls bacterial growth. The ozone also coagulates suspended matter, causing it to float. Optionally, a polymer coagulant can be added to facilitate coagulation. From the process tank, lint and other large particles are removed by a lint pulloff filter assembly, which can be a series of pressurized filter bags, a spin disk assembly, or other lint pulloff if assembly. The output water of this lint pulloff filter assembly flows to a multimedia pressure filter. The media is a gradient of layers of progressively smaller granular or particulate matter which removes suspended solids. The filtrate is passed to a clay filter which removes fats, oils, greases and other organic and chemical components. The filtrate from the clay filter is passed to a carbon filter (granular activated carbon) which removes remaining organic matter and chemicals. The water output from the activated carbon filter is passed to a final holding tank which also receives ozone, keeping the process water germ free as its waits for additional water needs. When demand is present, the system sends processed water through ultraviolet (or other energy similarly used) light to disinfect the water and to degrade the ozone so that it does not harm any components of the system or the washing machines and to minimize ozone released into the atmosphere. The system also can include a PLC controller and associated computer system for controlling pump rates, tank levels, filter parameters, backwashing scheduling, provide critical operational data, and other aspects of the system. Advantages of the present system include high recovery efficiency, improved bacterial growth control, and high return on investment. An additional advantage is the environmental benefits. We are quickly using up our limited natural resources, especially water. A recycling system that maximizes water recovery is a key element to water preservation. The present invention reduces the natural gas needs to heat the water. Furthermore, the substantial reduction in wastewater discharge eases the burden of water treatment and purification facilities to expand and accommodate the ongoing demand for services. The water recovery and recycle system of the present invention can also be used or adapted for use with other wash applications, such as boats and car wash systems. Other features and advantages of the present invention will become apparent upon reading the following detailed description of embodiments of the invention, when taken in conjunction with the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS The invention is illustrated in the drawings in which like reference characters designate the same or similar parts throughout the figures of which: FIG. 1 is a schematic view of a preferred embodiment of the present invention. FIG. 2 is a flow diagram of a portion of the system relating to the supply pump. FIG. 3 is a flow diagram of a portion of the system relating to the process pump. FIG. 4 is a flow diagram of a portion of the system relating to the sump pump. FIGS. 5A-5C are a chart of data from product run test. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In general, the present invention provides a wastewater recovery and recycling apparatus. The present invention can be used for recycling of wastewater from various applications, the variations of which will be discussed further hereinbelow. For the purposes of discussion of the preferred embodiments, the apparatus will be discussed in reference to a laundry operation environment, but it is to be understood by those skilled in the art as including other operations and applications. FIG. 1 shows an apparatus 5 according to a preferred embodiment of the present invention in which at least one and preferably a plurality of conventional washing machines 10 (not shown) output waste water to a trough (or collection pit) 12 . The trough 12 has a float 16 associated with a pump 19 which pumps water from the trough 12 via a conduit 20 to a process tank 22 , which is sized to accommodate the total output load of the washing machines 10 . For the purposes of the present invention, unless specifically described otherwise, the conduit referred to is preferably made of an inert, nonbiodegradable, material, such as, but not limited to, polyvinylchloride (PVC), other polymer, or metal. As such conduit is known to those skilled in the art, it may at times not be shown in the figures, but is intended to be used to convey fluid from one location to another in a watertight structure. Normally, wastewater (process water) from a laundry operation is discharged into an initial collection area (trough or pit). Temperatures can average from 100 degrees Fahrenheit up to about 140 degrees Fahrenheit and all equipment must be designed to handle these high temperatures, if necessary. Fresh water comes in at about 60 degrees Fahrenheit. The present invention can reclaim water from about 33-210 degrees Fahrenheit. The size of the system is determined by the company's washing machine load capacity. This determines their peak water flow. It is calculated by adding the pounds capacity per machine and multiplying it by the average amount of water used by the washing machines per pound of dry laundry. One then divides that number by the number of minutes between loads. For example, 3-300 lb washers represent 2,250 gls per washing cycle. With a 45 minute cycle, the system's peak water flow is 50 GPM and a 50 GPM system would be recommended. Supply Flow A supply pump 30 pumps water from a final holding tank 42 to the washing machines 10 . A float safety switch 31 is included in the holding tank 42 so that the supply pump 30 does not run dry. When the float safety switch 31 lowers to below a predefined level, a signal is actuated which turns off the supply pump 30 . A fresh water inlet 58 in the middle of the holding tank 42 provides a safety valve in case the water demands of the washing machines 10 is greater than the process water available. It also provides make up water from evaporation or to replenish lost process water from backwashing procedures. There is a mechanical float valve or float switch/solenoid valve assembly 59 attached to the fresh water inlet 58 , physically closing the inlet when the water level exceeds the inlet line. The fresh water supply should be designed with a pipe size as well as enough pressure to provide enough water if system has malfunctioned and cannot provide sufficient process water. A preferable design provides that the only time the supply pump 30 is deactivated due to low level in the holding tank 42 is if fresh water supply has dissipated. A pre-charge pressure tank 32 , located after the supply pump 30 , has an internal bladder (not shown) that fills with water and is designed to provide immediate water needs to the washing machines 10 upon demand while the supply pump 30 is turning on and beginning its function of water supply to the washing machines 10 . This pre-charge tank 32 has a switch 34 to turn the supply pump 30 on and off in response to, in part, the signal from the float safety switch 31 . If water usage is intermittent, preferably the pump 30 and switch 32 are actively used to reduce the occurrence of the low water levels; however, if water use is constant, the supply pump 30 can be left on continuously. Water is passed through an ultraviolet light source 36 , or other similar disinfecting electromagnetic radiation source (e.g., beta, gamma, X-ray radiation, or the like) known to those of ordinary skill in the art, which kills a substantial percentage of likely water-borne organisms, specifically bacterial and viral in nature. The ultraviolet light source 36 is commercially available from Aquionics, Louisville, Ky. The ultraviolet (or other energy similarly used) light also degrades the ozone so that it does not harm any components of the system or the washing machines and to minimize ozone released into the atmosphere. Water passing through the filter 36 is divided into two flows by a splitter (not shown). A portion (for example, but not limited to, a roughly equal split) of the water goes back via a conduit 38 as cold or tempered water to the washing machines 10 . The other portion of water goes back via a conduit 40 as hot water to the washing machine (if steam injected), a hot water heater 41 , or whatever heating source designed for that particularly environment. As the water level in a final holding tank 42 drops, a fill float switch 44 is actuated and turns on the process system (as described in detail hereinbelow) which turns on a process pump 46 , which sends water from the process tank 22 as long as there is sufficient water in the process tank 22 . Process Tank Waste water from the trough 12 is sent to the process tank 22 whenever the float switch 16 indicates that sufficient water is present. Ozone from an ozone generator 60 (as discussed further hereinbelow) is added to the process tank 22 to keep it germ and odor free and help coagulation. The process tank 22 is sized according to the calculations presented previously. Lint Filtration There are several alternative types of lint pulloff assemblies that can be used. One assembly, used for small systems uses a series of pressurized filter bag units 47 , available from a variety of sources such as Hayward Industrial Plastics, Clemmons, N.C. These units use internal non-woven polypropylene bags to catch large solids. The micron level in each bag varies, depending on turbidity of process water. An alternative second assembly, used for larger laundry environments can use, for example, but not by way of limitation, a shaker table or vibratory filter, which can remove suspended solids down to manageable levels. Another lint pull-off assembly is a spin disk 48 , with stackable disks 49 (not shown) with grooves of differing micron size levels. As process water travels around these disks 49 , a vertical arm which holds the disks sucks the process water through small holes in the arm, trapping suspended solids, such as lint, between and around these disks. As pressure rises, the spin disk provides an air assisted flush which causes the disks to separate and the suspended solids are discharged to sewer as backwash. This product, manufactured by Arkal Filtration Systems of Jordan Valley, Israel, is distributed commercially in the United States by A2 Water, of Gregory, Tex. Multimedia Pressure Filtration After lint filtration the process water is transported via a conduit (not shown) to at least one pressure tank 50 containing a multimedia pressure filter 51 . These pressure tanks 50 are preferably made of wound fiberglass and are light weight and long lasting or of epoxy coated steel, which are long lasting as well. It is to be understood that other materials can be used as are known to those skilled in the art. They are flanged at the top and bottom with a distributor head diffuser on the top and distributor arms at the bottom. The tanks 50 are filled with different types of earth media, each sized specifically to capture suspended solids of the same size. In a preferred embodiment anthracite is used first because it is light weight and coarse. It catches the largest solids. It is layered down to sand, then garnet, and then gravel is preferably used as the bottom base to secure and hold down the bottom distributor arms for backwashing. It is to be understood that other particulate matter can be used, as is know to those skilled in the art. Process water is sent at a pressurized state through the top opening and out the bottom opening. This is called the filtering mode. As process water continues to flow through these filters, the suspended solids continue to be “held” by the media inside. Each tank 50 can have a pressure differential gauge (not shown) which monitors high solids buildup when process water shows signs of high turbidity. The more solids that are accumulated, the higher the pressure differential gets. When the pressure differential exceeds the system limits, the system automatically shuts down and goes into backwash mode. There are also total flow limits (normal process) to limit the total water recycled between backwashes and timing limits, such as every night at midnight to insure regular backwashing regardless of volume. In a preferred embodiment, a flow limit is between backwashes. When performing a backwash, process, fresh, or a combination of both types of water is sent up from the bottom of the tank 50 with enough force to cause the media bed to lift up about 50% (although the actual percentage can vary). This action causes the trapped solids to separate from the media bed and are then pushed up and out of the top of the tank 50 and down the discharge pipe (not shown) to the sewer 51 . Each pressure vessel has a flanged opening at the top and bottom that are piped in two directions, one for water filtration and the other for backwashing purposes. Each “pipe” is controlled by a pneumatically actuated valve 52 or both pipes at the top or bottom can be controller by a three way pneumatic valve, which opens and closes depending on which mode the system is in, i.e., filter mode or backwash mode. Clay Filter The output of the process water from the multimedia pressure filter 50 then goes to another pressure filter called a clay filter 53 , which adsorbs fats, oils, grease, organics, heavy metals and chemicals, such as, but not limited to, dyes, surfactants, oils, grease and the like. The clay filter is composed of a combination of anthracite and organically modified “designer clay” and is purchased from Biomin under the trade name Organo-Clay™. The clay filter extends the life of the carbon media and increases the capacity of both carbon and clay to adsorb higher levels of FOG's as well as organics in the process water. The volume of clay needed, the retention time necessary to be effective and the backwashing sequence of the clay filter is the same as the carbon filter below. Carbon Filter The output of the process water from the from the clay filter then goes to another pressure filter called a carbon filter 54 , which removes any remaining organic matter and chemicals, such as, but not limited to, dyes, surfactants, oils, grease remaining after the clay filter. The carbon filter 54 also helps remove odors in the process water. The carbon filter 54 is preferably granulated activated carbon. The carbon filter 54 and the clay filter 53 adsorbs these items while the filtration of suspended solids through the multimedia process traps, holds, and later releases those solids to sewer discharge. Backwashing only helps regenerate the media; there are solids or chemicals removed in the backwashing process. The carbon filter 54 is backwashed to “fluff up” and redistribute the carbon and clay beds so that process water can “find” and absorb clean carbon and clay while traveling though the filter material. The output of the process water from the carbon filter 54 is transferred to the final holding tank 42 . An ozone generator 56 provides ozone bubbles, which are passed through the water in the holding tank 42 to help remove odor and to control bacterial growth. The ozone generator 56 can be a corona discharge type or an ultraviolet (UV) light frequency, which creates a low ozone volume concentration. One such generator is available from Prozone, Huntsville, Ala. If there is insufficient water to fill the holding tank 42 , a fresh water inlet 58 is opened to allow water to enter the holding tank 42 . An ozone generator 60 generates ozone which is injected in process tank 22 and the holding tank 42 . The ozone is a microcoagulant and binds to particles, causing them to coagulate and float facilitating filtration by the multimedia filter. Optionally, a polymer coagulant can be added to assist in coagulation if there are sufficient fats, oils, and/or grease present in the water, such as where the clothes are soiled with grease or oil. The polymer is preferably a cationic polymer. A preferred polymer coagulant is available as Zeta™ series from CIBA Specialty Chemicals (Suffolk, Va.). FIGS. 2-4 show the electrical control activation flow systems of the present invention. Supply Side Series FIG. 2 is a flow diagram of the supply pump 30 process, which is controlled by the operating pressure of the water going into the washing machines 10 . The pressure switch 34 monitors water needs of the washing machines 10 by pressure. When the pressure goes up, water needs have diminished and the signal through the safety float 31 in the holding tank 42 is terminated which causes the supply pump 30 to turn off. If pressure goes down and there is sufficient water in the final holding tank 42 , the pressure switch closes and the signal travels to the safety float switch 44 . If the safety float switch indicates sufficient water available, then signal continues to a supply contactor relay 70 in a central control panel 74 , which maintains the pump 30 is activated and the supply pump turns on. Process Series FIG. 3 is a flow diagram of the process pump process. There is a fill float 44 in the final holding tank 42 . A signal from the central control panel 74 goes through the fill float 44 . If the final holding tank 42 is full, the signal does not continue. When the level begins to go down, the signal continues and the process pump turns on. If the level of water in the process tank 22 is high, that signal will carry on to the process pump contactor 76 and the process pump 46 turns on. If the water level in the process tank 22 is low, that signal does not continue and the process pump is deactivated. Waste Pump Series If water is detected by the float switch 16 in the trough 12 , a signal is sent to the sump pump motor contactor 78 . The sump pump 19 is activated and water is pumped to the process tank 22 . When the discharge level in the trough 12 gets low, the sump pump 19 turns off to insure that the sump pump 19 does not run dry. If the process tank 22 runs to a high level, the fill float causes the signal to not continue, causing the sump pump 19 to turn off. Excess wastewater then overflows to the drain. Control Panel A PLC (program logic controller) control panel 72 automates the backwashing process providing power to all components as well as handling all signals from float switches. It may include a touch screen for easy operation feature as well as a computer system that makes it very easy to change timer settings and other functions of the system. The control panel 72 may also show the flowrate, total flow and/or other parameters, if desired. A remote access port, when connected to a telephone line, can provide valuable operational data from the flow meters. This data assists in monitoring the performance of the system as well as management data to document savings. This option increases the service level the company can provide to its customer, regardless of the location of the system. Advantages The present invention is advantageous because it addresses the particular waste stream of laundry. The majority of water contaminate is lint, which is addressed by the present system design. Lint acts as a magnet and clogs up surfaces in which is in contact. The pump of the present invention system is selected to have no sharp edges and a port size large enough to continually pass and so that it cannot be normally clogged and that any large enough lumps of lint are dislodged by the water pressure. Sources for such a pump include, but are not limited to, Gorman Rupp (Mansfield, Ohio) and Goulds (Seneca Falls, N.Y.). It is also important that the pump seal be chemically resistant, since acids and other harsh chemicals could damage a normal seal. The filter scheme preferably uses ozone as a microcoagulant and optionally a coagulating polymer. The spin disks, filter bag units, or shaker table units address the lint issue by efficient removal. Such filtration is not obvious in view of the prior art systems. The lint removal filters also reduce backwashing of the multimedia filter bed. Both the filter bag system and the lint shaker apparatus are preferable in that each will physically insolate and accumulate these solids to a external source to be disposed of outside the sewer system. The present invention limits the volume of solids sent to sewer systems, thus being environmentally desirable. An important aspect of novelty of the present invention is the nonobvious combination and configuration of filtration assemblies in the system to remove lint, organic and inorganic matter. The present invention reduces the amount and frequency of backwashing needed to maintain the filtration assemblies in good condition. Such reduction of backwashing reduces the amount of water lost and increases the efficiency of the system. In one installation of the present invention approximately 85% water recovery was obtained. It should be noted that approximately 10-15% of the system water is lost due to evaporation by the clothes dryers. Additionally, the filters work co-operatively in concert: the ozone coagulates material and the multimedia, clay, and carbon pressure vessels remove or adsorb the coagulated material. Without coagulation the filtration process might not be able to remove sufficiently the solids or FOG's. The water recovered by the present invention is sufficiently clean as to be used again in the washing machine without contaminating the clothes. Other prior art systems produce water which would be less clean and residual contaminants can get trapped in the clothes. Other systems which use reverse osmosis remove dissolved solids (ions), require a continual backflush. Therefore, one could expect a reverse osmosis system to have about a 50% maximum total water recovery. In contrast, the present invention dilutes total dissolved solids present in process water by using process water at strategic times as backwash water to the filters as well as providing fresh water as makeup water when the system is in backwash, effectively reducing TDS by dilution For example, in a laundry operation recycling 60,000 gallons per day, one could utilize approximately 3-5% of the daily process water to backwash the filters as well as an additional 10-15% fresh water to replace lost water to evaporation or when system is in backwash and not providing recycled water. One goal is to maintain a TDS level of between 500-1000 ppm in the final process water at any time. The example which follow provide sample results before and after recycle system. While other prior art systems are rinse water recovery systems, the present invention is a total wash water recovery system. The waste water recovery system of the present invention has at least about 75% total wash water recovery using a volume ratio of process water returned as recycled water to the typical amount of freshwater used without recycling. Another advantage of the present invention are the low operating costs, which result in higher return on investment. Additionally, the process provides a environmentally effective means to clean clothes while reducing our need for limited natural resources. Other Applications The apparatus of the present invention can also be used or adapted for use in other applications and for other recovery operations. For example, the present invention can be adapted for use in conjunction with boat cleaning systems. Boat cleaners produce paint chips in the waste water, which can be toxic. The ozone can coagulate oil and grease and the spin disk or filter bag units will trap and remove paint chips. In such a system the polymer coagulant may be omitted. A high pressure pump could be used as the supply pump 30 to provide the high wash pressure of about 1,000-1,500 psi commonly needed in such systems. For such a system the ultraviolet filter could optionally be omitted. The present invention can also be adapted for use in vehicle or other wash systems. The invention will be further described in connection with the following examples, which are set forth for purposes of illustration only. Parts and percentages appearing in such examples are by weight unless otherwise stipulated. EXAMPLES The EMI™ model 175 GPM system was first installed in February of 2001 and was up and running effectively March 1. As of Oct. 1, 2001, the system has recycled 13.5 million gallons of water and saved the owner over $100,000 in water, sewer, and energy savings. During the seven months of operation, it recycled 75% of the owner's laundry wastewater. FIGS. 5A-5C shows data of the recycle process and savings over a period of seven months. Laboratory analysis of the wash water, taken Oct. 2, 2001, showed the results as shown in Table 1. Numbers are in mg/L; standard published analytical methods are used; and, “J” is estimated concentration. Sample #1 represents the waste water and Sample #2 represents the recovered product water from the EMI175 system of the present invention. TABLE 1 Draft Draft Detection Detection Result Result Limit Limit Analytical Sample #1 Sample #2 Sample #1 Sample #2 Method Analyte (mg/L) (mg/L) (mg/L) (mg/L) SM 5210 B Bio- 177 123 8 8 chemical Oxygen Demand (BOD 5 ) EPA 160.2 Total 34 9 6 5 Suspended Solids EPA 160.1 Total 678 576 12 12 Dissolved Solids EPA 150.1 pH 9.08 7.5 — — (labor- atory) EPA 1664 Oil and 20 7 6 6 Grease SM9222 D Fecal 64000 34 2 2 Coliform per 100 ml per 100 ml Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims. It should further be noted that any patents, applications and publications referred to herein are incorporated by reference in their entirety.	An apparatus and method for recovering wastewater from laundry operations. A substantially closed loop series of tanks, conduits and pumps hold and transfer water output from a wash machine through a series of filters, including a lint pulloff filter, a multimedia pressure filter, a clay filter, and a carbon filter. The water is ozonated to coagulate suspended solids and to disinfect and is subjected to ultraviolet light to disinfect and to reduce residual ozone.	2

Subsets and Splits

No community queries yet

The top public SQL queries from the community will appear here once available.