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1966-01-01 | Coatings of a poor thermal conductor on metallic components may shorten the lengthy cooldown process prior to operation of cryogenic equipment, as shown first by Cowley, Timson, and Sawdye [^1]. Consequently, the operation and response of low-temperature systems may be improved by coating fluid-exposed surfaces of hardware (e.g., ducts, pumps). For instance, applications of Teflon coatings to cryopanels have been reported by Allen [^2]. | Cooldown of Insulated Metal Tubes to Cryogenic Temperatures | 10.1007/978-1-4757-0522-5_57 |
1966-01-01 | The rating of electrical generators and transformers has risen from 50 MVA to more than 600 MVA during the last twenty years. This has been possible through higher stresses on conductors, insulators, and magnetic materials. The progress made simultaneously on dielectric and magnetic materials has kept the corresponding losses at a relatively low level; however, the losses in the windings become substantial for the larger units, since the resistivity of copper has not changed. Cryogenics offers a new means in overcoming this difficulty by using either superconductivity or the normal conductivity of high-purity metals at low temperatures. | Cryogenics and Aluminum in Electrical Manufacturing | 10.1007/978-1-4757-0522-5_73 |
1966-01-01 | The purpose of this program was to evaluate the mechanical properties of electroformed nickel in order to determine its suitability for aerospace structural applications at room and cryogenic temperatures. In order to understand the interest in electroformed nickelj it is well to quickly review the electroforming process and some of Its attributes. | Mechanical Properties of Electroformed Nickel at Room and Cryogenic Temperatures | 10.1007/978-1-4757-0522-5_45 |
1966-01-01 | It is apparent that one of the most important of the basic criteria for structural materials for use in space vehicles is a maximum strength/weight ratio consistent with the additional requirements of toughness, fabricability, and compatibility with manufacturing, storage, and service environments. Liquid-propellant vehicles of the current generation, culminating with the S-IC booster stage of the Saturn V, are constructed principally of aluminum alloys, Weldability and low-temperature notch insensitivity requirements greatly influence alloy selection for fuel and oxidizer tankage. Various vehicles have employed Al-Mg alloys, 5456 and 5083 (Saturn I), the Al-Cu-Mg alloy 2014 (Titan II and S-II second stage and S-IVB third stage of Saturn V) and the Al-Cu alloy 2219 (S-IC booster stage of Saturn V), The highest-strength weldable alloys commercially available are 2014 and 2219, and in the tempers used these provide yield strengths in the 50 to 60 ksi range and ultimate tensile strengths of 60 to 70 ksi with weld joint efficiencies of 60 to 80% as-welded. | New Weldable High-Strength Aluminum Alloys for Cryogenic Service | 10.1007/978-1-4757-0522-5_46 |
1966-01-01 | Interest in the P-V-T behavior of mixtures at low temperatures has increased considerabiy in recent years. Such data are important with regard to the calculation of thermodynamic properties, gas separation and liquefaction, possible uses of mixtures as refrigerants, and phase equilibrium correlations, as well as to the study and evaluation of intermolecular potential functions. | The P-V-T Behavior of Nitrogen, Argon, and Their Mixtures | 10.1007/978-1-4757-0522-5_42 |
1966-01-01 | In a previous paper [^1] it was shown that vapor-liquid data could be correlated by means of a modified Redlich-Kwong equation of state. This result was unexpected in view of the simplicity of the equation, compared to other more complex equations which seemed to be necessary for the correlation of this type of data. | Calculation of Enthalpy Data from a Modified Redlich-Kwong Equation of State | 10.1007/978-1-4757-0522-5_43 |
1966-01-01 | The design of present and future aerospace systems demands that every advantage in a material’s capability be utilized in meeting the weight-strength requirement, Some of the advantages that can be utilized with great benefit are (1) proper choice of materials for the intended use, (2) use of biaxial strength increases when compared to uniaxial strengths, and (3) use of material property values that reflect increases due to the low operating temperature environment, The use of these three basic design advantages will, of course, result in more effective structures with lighter weights and lower cost. However, in order to utilize these advantages with confidence, design test data must be obtained and evaluated. It was the object of this research to evaluate the uniaxial, 1:1 biaxial, and 2:1 biaxial properties of three prospective materials over the temperature range of ambient temperature to — 423°F to obtain the desired design data. | Cryogenic Design Data and Criteria of Aerospace Materials Subjected to Uniaxial and Biaxial Stress States | 10.1007/978-1-4757-0522-5_49 |
1966-01-01 | The present investigation is part of a program to provide accurate, low-temperature, phase-equilibria data for binary systems of both technical and theoretical importance. It was pointed out in a previous paper [^1] that, particularly in the solid-vapor region, there was a deficiency of data for several systems of interest, specifically, the hydrogen and helium light-hydrocarbon systems. In that paper data were presented for the entire solid-vapor region of the hydrogen-methane system up to 150 atm. | Solid-Vapor Equilibrium in the System Helium-Methane | 10.1007/978-1-4757-0522-5_37 |
1966-01-01 | The requirement for long-duration (greater than one or two years) space flights is rapidly approaching, and the passive type insulation systems (surface coatings, foams, cork, superinsulations, etc) used for cryogenic tankage In short-duration flights (less than 24 hr) will probably be replaced by active insulation systems (refrigeration systems, reliquefaction systems, etc). The most immediate problem is for intermediate-duration flights (greater than 1 day but less than 1 yr), and for this problem superinsulation or radiation shields appear to be the most attractive insulations. Systems such as NCR-2 and Linde SI-62 have apparent thermal conductivity values when measured under high vacuum between room temperature and -320°F of 1 to 3 × 10^-5 Btu-ft/hr-ft^2-°F. Evacuated fiberglass and evacuated powder insulations have k -factors approximately 30 to 50 times higher than superinsulations, whereas plastic foams have k- factors 500 to 1000 times higher. If one compares these insulation systems on a kp or (kp) ^1/2 basis, the differences between systems are reduced, but the superinsulations are still significantly better than the other passive systems. | Investigation of Potential Low Temperature Insulators | 10.1007/978-1-4757-0522-5_33 |
1966-01-01 | Until recently, little work had been done on binary liquid-vapor systems with neon as one of the components. This was possibly due to the high cost of neon, which made it somewhat impractical to work with. However, in recent years the cost of neon has decreased, and the interest in neon has correspondingly increased. The neon-argon system has been investigated [^1–3], as has the neon-nitrogen system [^4]. Some work has been published on the liquid phase separation of neon-deuterium mixtures [^5,6], and one isotherm for the system neon-parahydrogen has been reported [^7], Some work on the neon-oxygen system has also been completed [^8]. | Liquid-Vapor Phase Equilibria of the Neon-Normal Hydrogen System | 10.1007/978-1-4757-0522-5_38 |
1966-01-01 | The advantages of having operating environments in the temperature region below 5°K for low noise levels in masers and other amplifiers for radio telescopes, communications satellites, military radar, superconducting computers, and other electronic equipment are now generally recognized. Because of the duty cycle and location of most of these applications, the need for a simple, highly reliable, closed-cycle refrigerator clearly exists. | Design of a Closed-Cycle Helium Temperature Refrigerator | 10.1007/978-1-4757-0522-5_12 |
1965-01-01 | Stainless steels are widely used in cryogenic construction, but this material is known to creep at low temperatures. The effect is important enough to often cause a breakdown of cryogenic equipment. | Creep Properties of 18–10 and 25–20 Stainless Steels at Cryogenic Temperatures | 10.1007/978-1-4684-3108-7_12 |
1965-01-01 | Many AIS I 300 series steels are used for a variety of applications at cryogenic temperatures. For some applications an accurate knowledge of Young’s modulus and the shear modulus is very useful. For this reason, the elastic moduli of a number of materials were measured isothermally at low temperatures in conjunction with other mechanical property tests. Some of the 300 series stainless steels exhibited a decrease between 76° and 20°K. This anomaly was documented by additional shear modulus measurements of AISI 302, 303, and 310 steels in both the annealed and cold drawn conditions. For these tests, a torsion apparatus was used to measure the shear modulus and a special strain gauge extenso-meter was used to measure the Young’s modulus. The decrease in moduli has been attributed to a paramagnetic to antiferromagnetic transition which occurs in 18Cr-8Ni alloys in the temperature range 37° to 42°K. This paper presents a brief summary of the experimental techniques and the experimental results of the above program. | An Anomalous Decrease of the Elastic Moduli at Very Low Temperatures in Some 300 Series Stainless Steels | 10.1007/978-1-4684-3108-7_5 |
1965-01-01 | Although helium containing no more than 5 to 50 ppm of total impurities is commercially available in quantity, there sometimes is a need for higher purity, particularly in fundamental helium research and for use as a carrier gas in chromatography. | Simple Technique for the Ultrapurification of Helium | 10.1007/978-1-4684-3108-7_48 |
1965-01-01 | The use of reinforced plastic laminates in applications encountering cryogenic temperatures is receiving increased attention from industry and government agencies. Such increased usage is logical since reinforced plastics have capabilities under this environment either unique or superior to other types of materials. Plastics, therefore, are a logical choice in a number of applications, particularly for space usage, when cryogens are involved. | An Assessment of Test Specimens and Test Techniques Useful to the Evaluation of Structural Reinforced Plastic Materials at Cryogenic Temperatures | 10.1007/978-1-4684-3108-7_14 |
1965-01-01 | The use of cryogenic fluids in rockets and missiles has resulted in a need for expanding knowledge of cryogenic engineering. One of the more acute problems encountered has been the static sealing of cryogenic fuel lines. The work described in this paper, while specifically oriented for the Saturn V launch vehicle, has application wherever LOX gaskets are required. | The Development of a New Cryogenic Gasket for Liquid-Oxygen Service | 10.1007/978-1-4684-3108-7_16 |
1965-01-01 | The requirement for cryogenic propellants, such as liquid hydrogen, liquid oxygen, liquid fluorine, and oxygen difluoride in current and proposed missiles, booster rockets, and space vehicles, has focused attention on the determination of properties of materials at extreme subzero temperatures. The need for thermal design data at cryogenic temperatures arises mostly from two fundamental requirements: (1) storage and containment of high-energy cryogens; and (2) direct exposure of space systems to the cryogenic conditions of a space environment. | Thermal Conductivity of Reinforced Plastics at Cryogenic Temperatures | 10.1007/978-1-4684-3108-7_18 |
1965-01-01 | Currently, large amounts of liquefied gases such as oxygen and hydrogen are used for space vehicle propellants. Aluminum alloy structural components of increasing design complexity, which are in contact with these liquids, must often withstand high stresses at extremely low temperatures. Aluminum forgings and welded structures, which are costly and usually require extensive machining, are used in many instances where a casting would be ideal. Suitable castings must have high strength and toughness and must be compatible with the adjoining aluminum alloy structure. A commercial casting alloy, having optimum properties for these requirements, has not been available. | Metallurgical Evaluation of a New Aluminum Casting Alloy Developed for Space Vehicle Use at Cryogenic Temperatures | 10.1007/978-1-4684-3108-7_4 |
1965-01-01 | This paper describes a method of providing cryogenic refrigeration for lead selenide, indium antimonide, etc., detectors in military systems. The technical history and philosophy of the unit are discussed. | Continuous Cryogenic Refrigeration for Three to Five Micron Infrared Systems | 10.1007/978-1-4684-3108-7_59 |
1965-01-01 | Experience indicates that with the development of materials with higher strengths, the tendency toward catastrophic low-ductility fractures increases, particularly at cryogenic temperatures. Continued efforts to use these higher-strength materials in structural units and yet to ensure against catastrophic low-ductility fractures have markedly increased the efforts aimed at evaluating the resistance of materials to rapid crack propagation. Formerly, coarse qualitative measures were sufficient, but more critical criteria for quantitatively rating materials and for realistically designing with them are now needed. | Evaluation of Fracture Characteristics of Aluminum Alloys at Cryogenic Temperatures | 10.1007/978-1-4684-3108-7_9 |
1965-01-01 | The problems associated with the expulsion of liquid in a zero gravity environment have long been recognized. Expulsion bladders have been used successfully in ambient temperature conditions, but little research has been directed toward the development of bladders for cryogenic liquids. During the past 20 months an intensive study of materials and bladders has been conducted. During the second phase of this program, several highly successful bladders were developed and progress was made over all previous work. A detailed report of this program is given elsewhere.* | Expulsion Bladders for Cryogenic Liquids | 10.1007/978-1-4684-3108-7_46 |
1965-01-01 | Recent development of liquid hydrogen as a fuel for space vehicles has created a requirement to establish design criteria which will eliminate potential hazards due to propellant leakage or venting into confined areas. | A Combustion Test Program to Establish Design Criteria for Liquid-Hydrogen-Fueled Space Vehicles | 10.1007/978-1-4684-3108-7_30 |
1965-01-01 | One of the most important problems of the design and metallurgical engineers is the proper selection of engineering alloys for structural applications in cryogenic-fueled missiles and space vehicles. The basis for selection of a material is dependent upon many factors, the most important of which are strength, resistance to catastrophic fracture, availability, and fabricability. Materials with a high strength-to-density ratio are required for flight vehicles in order to minimize the weight and meet design requirements for payload capabilities. The alloys must possess a high degree of toughness or resistance to brittle failure in order to meet the reliability requirements. These alloys must maintain their high strengths and toughness during ground handling and flight conditions which may impose severe environments. Temperatures may range from nearly absolute zero, due to cryogenic fuels and to certain conditions in outer space, to elevated temperatures as a result of atmospheric frictional heating, engine heating, etc. Operating conditions may also include high stresses, vibration, impact and repeated loading, thermal shocks, and subjection to radiation and vacuum. The materials selected must be capable of being welded, formed, and machined in order to fabricate structural components, and must maintain their strength and toughness in the fabricated condition. Those alloys which meet the above technical requirements must be available in the sizes, forms, shapes, and quantities required, and at a cost which is not prohibitive. | Mechanical Properties of Several 2000 and 6000 Series Aluminum Alloys | 10.1007/978-1-4684-3108-7_8 |
1965-01-01 | This paper presents the results of an experimental program to determine the effect of cryogenic temperatures on spark ignition of hydrogen in oxygen and nitrogen mixtures. The parameters investigated are breakdown voltage, quenching distance, flammability limit, and spark ignition energy. Analytical methods for predicting values of most spark ignition parameters for engineering application are cumbersome. Very few data are available in the literature on ignition at cryogenic temperature. This experimental program is intended to supplement the literature data. Data are presented for gaseous mixtures at 180°R and 5, 14.75, and 40 psia. Since ignition and breakdown voltage are influenced by mechanical configuration and materials used in the test apparatus, several tests were conducted at standard conditions, 520°R and 14.75 psia, as a basis for data comparison. | Spark Ignition Parameters of Cryogenic Hydrogen in Oxygen and Nitrogen Mixtures | 10.1007/978-1-4684-3108-7_31 |
1964-01-01 | Until recently, data on the fatigue behavior of materials at cryogenic temperatures have been sparse, and information of this type for nonmetallic materials has been practically nonexistent. A preliminary search of published data revealed only a limited amount of information on fatigue characteristics of materials at cryogenic temperatures. Most of these data have been derived from flexural fatigue tests, and apply almost exclusively to metals. | Tensile Fatigue Testing at Temperatures Down to 20°K | 10.1007/978-1-4757-0525-6_16 |
1964-01-01 | Large vessels for the storage of cryogenic fluids are field-erected, rather than assembled in a factory, because it is difficult to ship parts much larger than 12 ft in diameter. It is impractical to insulate these field-erected tanks with high-efficiency multilayer insulations by conventional methods, so a new technique has been devised to apply superinsulations to vessels which cannot be moved or rotated. | Quilted Superinsulation | 10.1007/978-1-4757-0525-6_6 |
1964-01-01 | A variety of components now available or under development must be cooled to cryogenic temperatures for efficient operation. Infrared detectors and other semiconductors represent one group of such devices which dissipate less than 2 w of heat when in operation, and many produce less than 0.1 w of heat. | Cooling to Cryogenic Temperatures by Sublimation | 10.1007/978-1-4757-0525-6_59 |
1964-01-01 | At present, the 2000(Cu), 5000(Mg), 6000(Mg-Si) series provide most of the aluminum alloys used in cryogenic applications. Established alloys in the 7000(Zn) series, including 7075, 7079, and 7178, are more sensitive to notches than many of the alloys of the above types [^1,2] and have not been seriously considered. Recently, several new 7000-series alloys have been introduced with appreciably greater notch toughness than other alloys of this type. It is. expected that these new alloys may be of considerable use in cryogenic applications. | Notch Sensitivity of Aluminum-Zinc-Magnesium Alloys at Cryogenic Temperatures | 10.1007/978-1-4757-0525-6_13 |
1964-01-01 | Knowledge of the influence of adsorbed impurities upon catalyst effectiveness is of theoretical and practical interest. The ortho-parahydrogen conversion mechanism in heterogeneous catalysis involves the adsorption of hydrogen. Any adsorbate which competes with hydrogen may be expected to reduce the catalyst effectiveness unless this competing adsorbate is also a catalyst. The extent and character of the reduction due to adsorption of an impurity may illuminate the catalyst behavior. Understanding of the effect of an impurity upon catalyst performance permits operating limitations to be placed upon the concentration of impurities in the feed stream to a liquefaction plant [^1]. | Effect of Adsorbed Nitrogen on Catalytic Activity of Ortho-Parahydrogen Conversion Catalysts | 10.1007/978-1-4757-0525-6_26 |
1964-01-01 | Several years ago, the aluminum industry Introduced the high-strength, weldable aluminum-magnesium alloys, particularly alloy 5083, to the engineering industry for use as pressure-vessel and cryogenic-tankage material. Since then, this organization has been directing its research efforts toward the development of a high-strength, heat-treatable, yet weldable, aluminum alloy which would permit greater maximum allowable stresses than are now approved for 5083 alloy under the ASME Boiler & Pressure Vessel Code [^1]. Prior investigations, reported previously, have described the mechanical properties of alloy 5083 at cryogenic temperatures to -452°F [^2–4]. | Performance of a New Cryogenic Aluminum Alloy, 7039 | 10.1007/978-1-4757-0525-6_14 |
1964-01-01 | The metastable superheat Δ T attainable by a liquid above its saturation temperature is important in nucleate boiling. Aside from the boiling description, however, a knowledge of AT also provides criteria for heat transport transition when bubble formation is entirely suppressed. A nonboiling liquid may be heated to the maximum metastable superheat before it disintegrates [^1]. As soon as the wall excess temperature increases beyond the limiting superheat value, the system will enter the Leidenfrost regime, within which liquid is converted into the completely disordered phase when it approaches the hot walls. | Metastable Superheat in Nucleate Boiling of Cryogenic Liquids | 10.1007/978-1-4757-0525-6_9 |
1964-01-01 | The need for more extensive tabulations of thermodynamic property data for the cryogenic fluids and for tabular values where previously only graphical data were available was recognized several years ago for use in the work being carried out in this laboratory. As a consequence, a program was undertaken in the Cryogenic Processes Section which has resulted in the publication of tables of properties for helium, normal hydrogen, and nitrogen, This compilation of thermodynamic data from the literature has been continued in the Cryogenic Data Center and new publications with tabular values are now available for oxygen, argon, neon, and carbon monoxide. These publications indicate the experimental data considered, the compilation methods used, and the estimated accuracy of these tabulations. | The Correlation of Thermodynamic Properties of Cryogenic Fluids | 10.1007/978-1-4757-0525-6_3 |
1964-01-01 | This paper provides expressions for heat and mass transfer to the frost surface and information regarding the frost formation which can be used by designers of cryogenic systems with uninsulated surfaces, and furthers the general understanding of the frost* phenomena. | Analysis of the Frost Phenomena on a Cryo-Surface | 10.1007/978-1-4757-0525-6_11 |
1964-01-01 | The problem of sealing pressurized containers in cryogenic applications has been quite significant in the development of launch vehicles for space applications. Two basic concepts of sealing are involved: (1) seals, such as O-rings, lip seals, flat gaskets, etc., used in sealing joints of cryogenic storage containers and transfer systems, and (2) sealants applied by brush, spatula, or caulking gun, and cured in place for sealing skin portions of such containers as instrument and payload compartments, cryogenic tanks, and other related components of launch vehicles that will be exposed to cryogenic environments. | Development of Organic Sealants for Applications at Cryogenic Temperatures | 10.1007/978-1-4757-0525-6_19 |
1964-01-01 | The insulating effectiveness of multilayer insulations and the influence of different physical conditions on their performance are of prime importance in the use of liquid hydrogen in future space missions. To better define the problems associated with the storage of liquid propellants in space [^1] we are investigating a number of variables which influence the thermal performance of the multilayer insulations. Considering the conditions under which these insulations may be used, the effects of the following variables on their thermal con« ductivity are of particular interest: (1) boundary temperatures; (2) gas pressure; (3) gas type; (4) mechanical load; (5) number of shields and thickness; and (6) thermal shorts and discontinuities. | The Performance of a Double-Guarded Cold-Plate Thermal Conductivity Apparatus | 10.1007/978-1-4757-0525-6_7 |
1964-01-01 | There have been many national and international scientific and technological gatherings in recent years in which the subject of discussion has centered around physical and chemical investigations at extremes of environment. Phenomena at extremely high pressures, at very high temperatures, and at cryogenic temperatures have all attracted the attention of many in the scientific community because of the dual significance of much of the work to both the fundamentalist, who is interested in understanding nature, and to the applied scientist, who is concerned with the useful aspects of the products and phenomena that may be produced. | Chemical Reactivity and Synthesis at Cryogenic Temperatures | 10.1007/978-1-4757-0525-6_1 |
1964-01-01 | The improved postlaunch reliability of important components and systems in the space program is due, in part, to increased emphasis on check-out and performance tests under simulated space conditions. The size of chambers used for these tests has continued to increase to accommodate the larger vehicles. It has been possible to provide and sustain high vacuums in these large chambers, even with high gas loads, by the use of cryopumping together with conventional mechanical and oil-diffusion-type vacuum pumps. The refrigeration for cryopumplng has been supplied with dense-gas helium refrigerators. These refrigerators, usually operating below 20°K, range in capacity from a few watts to several kilowatts. Refrigeration cycles of this type have been previously described by various authors [^1–3]. This, paper presents an analysis of the thermodynamic cycle usually employed and a description of the components, operation, and performance of a 1-kw unit. | Helium Refrigerators for Operation in the 10°–30°K Range | 10.1007/978-1-4757-0525-6_60 |
1963-01-01 | The temperature dependence of the extended X-ray absorption fine structure was investigated in the range from 9-573°K. It was found that the temperature dependence of the intensity of the fine structure features was quantitatively accounted for by applying the Debye-Waller factor. A change in position of the features with the expansion and contraction of the lattice was also observed. These experimental data suggest a simple diffraction (Krönig theory) mechanism; however, the observed absorption minima do not agree with those predicted by the Krönig equation. The single-crystal. X-ray spectrometer. X-ray cryostat, and experimental conditions are also discussed in some detail. | X-Ray Absorption Fine-Structure Investigations at Cryogenic Temperatures | 10.1007/978-1-4684-8685-8_27 |
1963-01-01 | The first part of this paper will be a discussion of some of the physical limitations encountered in far infrared spectroscopy using the echellette grating monochromator with filters to separate orders. An inclusive discussion of the methods of far infrared spectroscopy using gratings and filters will be omitted because these methods are well known and used in hundreds of laboratories. In about the past 5 years such spectroscopic systems have become available from instrument manufacturers. The last part of the paper will describe some less common systems using interferometric equipment. There will be an account of some new detectors which can be applied to far infrared spectroscopy. | Methods of Far Infrared Spectroscopy | 10.1007/978-1-4684-8685-8_3 |
1962-01-01 | A mechanical properties test program has been completed between 300° and 4°K on several annealed austenitic stainless steels. The extensive results are in the process of being correlated for final publication. However, some of the properties show an interesting anomalous behavior and are worthy of preliminary discussion because of their special relation to the martensitic transformation characteristics of the alloys. The results are based on analysis of the tensile strength, notched tensile strength, and their resulting ratio for AISI-304L sheet and also X-ray analysis of the accompanying transformation characteristics. | Martensitic Transformation Products and Mechanical Properties of Austenitic Stainless Steels at Low Temperatures | 10.1007/978-1-4757-0531-7_60 |
1962-01-01 | It has been well established that the characteristics of single-crystal germanium doped with certain impurities are suitable for resistance thermometry at low temperatures. Indium was used as the dopant by Estermann [1] and by Friedberg [2], whereas Kunzler et al. [3] have described in detail a four-lead thermometer using arsenic as the major impurity. We have employed galliumdoped germanium with an impurity concentration of about 6 · 10^-16 cm^-3 and find that it has a characteristic which is useful over the range from 1° to 40°K. | Gallium-Doped Germanium Resistance Thermometers | 10.1007/978-1-4757-0531-7_63 |
1962-01-01 | The uniaxial mechanical properties of most structural metals tested at liquid-hydrogen temperature show the yield, ultimate, and weld strengths to be substantially increased over their room-tempe rature values. The tensile notch and impact strengths, however, are generally lower than their room-temperature values, indicating a tendency toward brittle behavior. Since notch and impact strength values are comparative data only and are not values which can be directly correlated with actual design problems, the question arises as to how this extremely low-temperature service affects the structural reliability of missile tankage. This question could be answered by the testing of a full-scale statictest article for each design. A full-scale static test with liquid hydrogen, however, is extremely costly and hazardous. A failure could result in a fire or in explosion and no conclusive information would be obtained, Therefore designers of liquid-hydrogen missile tankage systems are compelled to be conservative to ensure a successful static test. The resultant weight penalty is sufficient reason for the construction of a test fixture that closely simulates design conditions at cryogenic temperatures. | Biaxial Mechanical Properties of High-Strength Weldable Aluminum Alloys | 10.1007/978-1-4757-0531-7_56 |
1962-01-01 | Liquid neon is a cryogenic fluid possessing unique characteristics. Previously, there has been only limited discussion of these characteristics since it was not readily available for use. Now neon has become available in quantity; consequently, an understanding of its characteristics, design of equipment and the techniques used to handle it has become increasingly important. | Liquid Neon and Advanced Techniques Used in Design of Liquid-Neon Equipment | 10.1007/978-1-4757-0531-7_72 |
1962-01-01 | The need for multiple restart capability in liquid rockets and auxiliary power units in satellites has made the development of suitable methods of delivering liquid from a container under a zero-gravity environment of prime Importance. The problems of delivering cryogenic liquids under a zero-gravity environment are compounded due to the very low temperatures and low heats of vaporization associated with these liquids. | Expulsion Bladders for Cryogenic Fluids | 10.1007/978-1-4757-0531-7_19 |
1962-01-01 | Elastomers offer the cryogenic engineer a dramatic demonstration of how the properties of some materials change radically when cooled to cryogenic temperatures. These materials have room-temperature properties of high extensibility and forcible quick retraction but, without exception, become hard and glass-like when sufficiently cooled, and thereafter behave like crystalline solids. Around this so-called glass-transition temperature, the modulus of elasticity may increase by a factor of 400 to 1000, and the coefficient of expansion may decrease by a factor of three or more [1]. Because of these changes, elastomers are not commonly used at cryogenic temperatures to solve problems for which they would be used at room temperature. Where an elastomer O-ring would perform the function of astatic seal at room temperature, countless designs are now being used to seal cryogen transfer lines, fuel and oxidizer missile components, experimental apparatus, and so on. However, none of these alternatives has met with universal approval, and all exhibit at least one of the disadvantages of high cost, poor performance, or complexity. | The Application and Behavior of Elastomers at Cryogenic Temperatures | 10.1007/978-1-4757-0531-7_42 |
1962-01-01 | The efficient design of low-temperature hydrogen heat exchangers requires detailed heat-transfer information relevant to temperature gradients, heatfluxes, surface conditions and geometry, materials of construction, flow rates, and other important variables. This investigation determined only the relationship between the individual film heat-transfer coefficients and the variables of temperature difference and heat flux for boiling and condensing hydrogen films on a smooth vertical tube surface. The boiling occurred on the outside surface while the condensing took place on the inside surface. | An Experimental Investigation of the Individual Boiling and Condensing Heat-Transfer Coefficients for Hydrogen | 10.1007/978-1-4757-0531-7_49 |
1962-01-01 | The mechanical properties of metals and alloys are greatly influenced by the type and concentration of solid-state defects. Such defects, regardless of the method of their production, are capable of moving about if the temperature is sufficiently high. It is by this mechanism that the effects of nuclear irradiation as well as heat treatment or work hardening are annealed out. In most common metals, defects are mobile at temperatures as low as 54°R. Cottrell reports that in high-purity copper, for example, after irradiation below 18°R, most of the change in electrical resistivity anneals out at temperatures below 63°R [1], Thus, it is seen that annealing, even during irradiation, is the rule rather than the exception. | Tensile—Compression—Shear Loop for Irradiation Testing at Cryogenic Temperatures | 10.1007/978-1-4757-0531-7_53 |
1962-01-01 | In selecting an aluminum alloy for cryogenic service, the design engineer must consider the form of the mill product, its thickness, and the type of service condition it will encounter. All factors must be properly weighed, and the alloy selected should be that which has the best properties at the operating cryogenic temperature. | Tensile and Impact Properties of 7075-T6 and 7079-T6 Plate, Hand Forgings, and Tensile Properties of Plate MIG Weldments between 75° and -320°F | 10.1007/978-1-4757-0531-7_57 |
1962-01-01 | In recent years, large amounts of liquefied gases such as oxygen and hydrogen have been used for steelmaking and for rocket and missile propellants. Structural components which contain these liquids must often withstand high stresses at extremely low temperatures. To obtain design data for structures which will be exposed to these liquefied gases, it is necessary to evaluate the likely candidate materials at operating temperatures. Aluminum with its favorable face-centered-cubic structure has good possibilities in this field. Cryogenic properties of certain aluminum alloys have recently been determined [1–6], However, little work has been done comparing the various 5000-series alloys, especially at temperatures as low as -423°F, and almost no work has been done in evaluating plate material which could be used in construction of large storage containers for the low-temperature liquefied gases. | Tensile Behavior of Parent-Metal and Welded 5000-Series Aluminum Alloy Plate at Room and Cryogenic Temperatures | 10.1007/978-1-4757-0531-7_58 |
1961-01-01 | Several methods are used to transfer cryogenic liquids. These vary from mechanical means, such as with a transfer pump, to pressurizing with a gas. There have been a number of papers describing these techniques in past conferences. The pressurizing gas may be the same as the fluid being transferred to avoid contamination or it may be a gas which will not condense during the transfer. A typical example of the latter would be the use of helium gas for pressurizing liquid oxygen, since the helium would not condense at liquid oxygen temperatures. Where product purity would not be important it might be useful to pressurize oxygen with nitrogen gas although some condensation will probably occur depending on the transfer pressure. | Pressure Phenomena During Transfer of Saturated Cryogenic Fluids | 10.1007/978-1-4757-0534-8_28 |
1961-01-01 | The theory of superconducting rectification is based upon “resistance switching.” A superconducting element can be shifted from a superconducting state (zero resistance) to a normal state (resistive) and back again by varying the intensity of a magnetic field surrounding the element. | Superconducting Rectifiers | 10.1007/978-1-4757-0534-8_15 |
1961-01-01 | The recent and continued development of long range space and missile vehicles powered by cryogenic fuels and/or oxidizers has created the need for reliable, accurate, and simplified systems for control and/or measurement of liquid level. | A New Method for Detection of Liquid Level of Cryogenic Fluids | 10.1007/978-1-4757-0534-8_43 |
1961-01-01 | Superconductivity, the simultaneous total disappearance of electrical resistance and the appearance of perfect diamagnetism, is a strange property of certain elements and alloys which appears in temperature ranges close to absolute zero. | Superconductivity | 10.1007/978-1-4757-0534-8_14 |
1961-01-01 | The interest in the use of aluminum alloys for cryogenic applications has stemmed from the long-recognized increases in tensile properties of these alloys at depressed temperatures [1–4]. The fact that the elongations, as well as the strengths, of most aluminum alloys increase as temperature decreases, and that the reduction of area values are about the same at -320ºF as at room temperature, formed the basis for further study of the properties of these alloys at low temperature. Also of importance was the often demonstrated absence of transition in fracture behavior. | New Data on Aluminum Alloys for Cryogenic Applications | 10.1007/978-1-4757-0534-8_67 |
1961-01-01 | This paper has two purposes: the first, to present a broad picture of low temperature cooling with specific reference to operation under space conditions; and second, to outline steps contributive to the development of successful designs of low temperature cooling. | Spaceborne Cryostats for Continuous Operation | 10.1007/978-1-4757-0534-8_10 |
1961-01-01 | This paper presents a quantitative description of a floating insulation for the surfaces of cryogenic fluids stored in open-topped dewar flasks. The technique makes use of polystyrene beads, which provide good thermal insulation, conform to a complex surface geometry—such as partially immersed equipment—and act as a good electrical insulator as well. Since the beads float on the liquid surface, they need not be removed when refilling the container and provide an easily visible liquid level indication. | Floating Polystyrene Beads as Insulation for Cryogenic Fluids | 10.1007/978-1-4757-0534-8_58 |
1961-01-01 | Increasing demand for helium containing less than 50 ppm total impurities for missile and atomic energy applications requires reliable determination of the trace impurities in Grade-A helium,** The impurities should be identified and their concentrations should be known within a tolerance of 1 ppm. | A Method and Apparatus for Concentrating Trace Impurities in Analyzing Grade-A Helium | 10.1007/978-1-4757-0534-8_42 |
1961-01-01 | Recent developments in semiconductor physics have produced infrared detector materials with increased detectivity out to the 40 μ wavelength region of the electromagnetic spectrum, In order to realize maximum sensitivity to wavelengths above approximately 6 μ, it is necessary to cool the detecting elements to temperatures ranging from 4° to 200°K. In the 2–6 μ wavelength region, detector materials exhibit improved performance when refrigerated to a lesser degree. This paper is primarily concerned, however, with techniques of cooling these devices to cryogenic temperature levels. | Infrared Detector Refrigerators | 10.1007/978-1-4757-0534-8_37 |
1961-01-01 | The large-scale use of cryogenic liquids is becoming commonplace. For some time now, missile launching sites have used large quantities of liquid oxygen and nitrogen. Liquid hydrogen and fluorine may soon be in use as primary rocket propellants and certain research and development programs within the AEG and NASA require the use of extensive refrigeration at cryogenic temperatures. | An Analytical Method for Estimating Gas Requirements in the Pressurization and Transfer of Cryogenic Fluids | 10.1007/978-1-4757-0534-8_27 |
1961-01-01 | An elastomer O-ring lightly squeezed against a flat surface makes an excellent seal at ordinary temperatures, as has been amply demonstrated by the widespread acceptance of O-ring seals for countless applications. It is natural to hope that similar simple seals can be used for service at cryogenic temperatures. When an ordinary O-ring seal cools, however, the elastomer becomes brittle at some temperature not far below room temperature, then shrinks until it loses contact with the flat surface and the seal fails. If an O-ring seal is to hold at cryogenic temperatures, a way must be found to maintain the contact between the flanges and O-ring as the parts cool. | Elastomers for Static Seals at Cryogenic Temperatures | 10.1007/978-1-4757-0534-8_23 |
1961-01-01 | Very low temperatures are encountered in current and proposed missiles and space vehicles due to title use of cryogenic propellants such as liquid oxygen and liquid hydrogen and due to the near absolute zero temperatures encountered under certain conditions in outer space. Tjerefore, the properties of engineering materials at these extreme subzero temperatures are becoming of prime importance to the design engineer. | Properties of 7000 Series Aluminum Alloys at Cryogenic Temperatures | 10.1007/978-1-4757-0534-8_64 |
1961-01-01 | In connection with its many liquid propellant rocket-engine programs over the last five years, Rocketdyne has had extensive experience in the design and development of components for cryogenic environments. A partial list of components would include propellant gate valves, poppet and swing-type check valves, relief valves, vent valves and pressure regulators in both missile weight and facility equipment planning. An integral and important part of the development of these components has been the selection of non-metallic materials which would perform under the most severe environmental conditions. The determination and evaluation of the standard physical properties of these materials at exogenic temperatures is an important factor in the selection of materials for cryogenic designs. Toward this end, tests have been made with non-metallics at -320°F to obtain some of the basic low-temperature mechanical properties of these materials. In most instances this data was obtained for selected materials with a view toward the application of these materials in a particular design configuration. There usually was not time to broaden the scope of the Investigations beyond a particular design problem to include all of the parameters which would be of interest to designers in general. | A Simplified Determination of Crystallinity of Fluoroplastics and the Prediction of Their Behavior at Cryogenic Temperatures | 10.1007/978-1-4757-0534-8_66 |
1961-01-01 | Progress in the field of cryogenic engineering during the last few years has introduced many new problems relative to the handling, storage, transfer and use of cryogenic liquids. Even though the handling and use of these liquids in large quantities is no longer a difficult task, more efficient and feasible methods must be developed. | Evaluation of Ball Bearing Separator Materials Operating Submerged in Liquid Nitrogen | 10.1007/978-1-4757-0534-8_26 |
1960-01-01 | The performance of any cryogenic storage and transfer system depends in no small measure on the vacuum-tightness of various joints. The workmanship which may be obtained in any assembly involving welding or soldering may well provide some uncertainty in the mind of the designer and can easily be responsible for poor performance of equipment. On the other hand, the assurance of high-quality workmanship may encourage the designer to try difficult assemblies both in the laboratory and on a larger scale. | Vacuum Gaskets for Use at 20°K | 10.1007/978-1-4757-0537-9_68 |
1960-01-01 | Properties of 9 Per Cent Nickel Low Temperature Steel | 10.1007/978-1-4684-3105-6_42 | |
1960-01-01 | A calorimetric method^1 has been used for trace oxygen analysis in the CEL-NBS hydrogen liquefier. In this method any oxygen present is catalytically combined with the hydrogen to form water. The resulting temperature rise of the gas is measured by a sensitive thermopile. The analyzer is capable of detecting as little as 2 ppm of oxygen. With the introduction of a catalyst to produce high para liquid hydrogen in the liquefier this system no longer operates with its former precision. The boil-off gas from the liquid hydrogen receiver and from a dewar being filled is recirculated through the system. The result is a non-equilibrium ortho-para mixture in the room temperature gas at the oxygen analyzer. The catalyst used to combine the oxygen and hydrogen effectively converts this high-para gas to normal equilibrium hydrogen. Since the conversion is an endothermic reaction, the analyzer reads too low and may even give negative readings. | Modification of a Calorimetric Oxygen Detector for use with Non-Equilibrium Hydrogen | 10.1007/978-1-4684-3099-8_28 |
1960-01-01 | Temperature control of a spontaneously cooling object by means of regulated electric heating may be achieved with a low-level, dc amplifier of thermocouple or bridge signals [1,2] together with a dc power-regulating amplifier [3–6]. The use of dc heating current avoids ac pickup by low-level circuits in the cryostat. Although dc amplifier circuitry is well known [7–10] the modification of direct-coupled circuits, for purposes other than the original design, may be surprisingly difficult. | An Improved dc Power Regulator | 10.1007/978-1-4757-0537-9_67 |
1960-01-01 | The ever increasing interest in cryogenic fluids for research and the economic advantages of liquid supply to small consumers of atmospheric gases has dictated the need for high performance portable cryogenic containers. To meet this need Einde Company has devoted a great deal of research effort in this direction. The end result has been the development of a line of high performance portable containers to transport, store and dispense oxygen, nitrogen and argon in the liquid state. The main requirements for this service are ruggedness, portability, simplicity, ease of utilizing the product and low-product loss. | High Performance Cryogenic Containers | 10.1007/978-1-4757-0540-9_13 |
1960-01-01 | Two types of flowmeters have been calibrated volumeixically in liquid hydrogen. Two turbine-type flowmeters (a 1½-in.-diameter 5 to 110 gpm, and a 1-in.-diameter 2 to 40 gpm) have been calibrated within their respective ranges. A 1-in. orifice flowmeter has also been calibrated within the same range. | Results of Flowmeter Calibration in Liquid Hydrogen | 10.1007/978-1-4757-0537-9_36 |
1960-01-01 | Pump designers have for many years experienced the phenomena of a difference in the cavitation performance of a single pump handling different fluids. From a data correlation view point the mixed fluids such as jet fuels and water with entrained air present the most difficult problem. However, the single fluids such as water at different temperatures, liquid oxygen, and liquid nitrogen also exhibit different characteristics. | Comparison and Correlation of Centrifugal Pump Cavitation Test Results Handling Liquid Oxygen and Water | 10.1007/978-1-4757-0540-9_22 |
1960-01-01 | This paper describes some of the work done at the Boeing Airplane Company on crew compartment environmental control. Primarily, the discussion will be about a test run to determine the feasibility of a cryogenic — supplied “wash-through” cabin conditioning system. This system was designed to provide a “shirtsleeve environment” in the crew compartment. | Crew Compartment Environmental Control Utilizing Cryogenic Fluids | 10.1007/978-1-4757-0537-9_37 |
1960-01-01 | Many investigators including Pecklet, Clark and Ellis have performed tests and made theoretical analyses of dynamic bubble behavior in order to explain formation, growth, collapse and shape change of these bubbles. However, the majority of these investigations have been made for static conditions of the primary phase. | An Analysis of Dual-Phase Flow at the Inlet to a Centrifugal Cryogenic Pump | 10.1007/978-1-4757-0540-9_23 |
1960-01-01 | The title, “Theory Versus Practice in Low Temperature Engineering” indicates that theory and practice are incompatible. It is not incompatability that we are talking about, but the difference between laboratory and large scale industrial practice in low temperature engineering. We will consider low temperature refrigeration schemes, heat exchangers, rectifying columns and condensers, and insulation of liquid oxygen storage transport vessels. | Theory versus Practice in Low Temperature Engineering | 10.1007/978-1-4684-3099-8_54 |
1960-01-01 | The production and distribution of liquefied atmospheric gases is considered today by many to be a major industry. The most important of these gases is oxygen. In 1953, according to the Bureau of the Census, production in the United States of high purity oxygen amounted to 25 billion cubic feet. This is enough to fill a cube having a dimension of more than a half mile. “Tonnage oxygen,” made in private plants and consumed on the premises, is not included. | Cryogenic Engineering in the Production and Distribution of Liquefied Atmospheric Gases | 10.1007/978-1-4684-3099-8_34 |
1960-01-01 | The fuel load in today’s missiles usually consists of at least one cryogenic liquid. In a missile second stage this cryogenic liquid is heated significantly by aerodynamic friction. To get maximum use from a propellant load, it is desirable to determine the effect of aerodynamic heating on the pool of cryogenic liquid. Since the net positive suction head (NPSH) is that portion of the total head above saturation pressure, a rise in the saturation temperature of the liquid due to aerodynamic heating will decrease the NPSH. Thus, the problem is one of defining drain temperatures resulting from flight conditions to determine the NPSH available. | A Survey of Stratification in a Cryogenic Liquid | 10.1007/978-1-4757-0537-9_53 |
1960-01-01 | Early attempts to describe the basic nature of radiation damage were based upon measurement of physical changes occurring in materials, which were bombarded at or near room temperature. Almost at the outset of research in this field, it was recognized that some radiation induced defects might be mobile below room temperature. Observation of these defects could be made only if they were frozen into the material during bombardment and subsequently studied under controlled low temperature conditions. | Reactor Irradiations at 15°K | 10.1007/978-1-4684-3102-5_18 |
1960-01-01 | Close examination reveals that liquid level devices measure either the position or height of a liquid surface above a fixed reference point, or the hydrostatic head or pressure developed by the liquid. A level measurement need not be expressed strictly in terms of inches or feet, nor in terms of the hydrostatic pressure developed. It may be conveniently interpreted in terms of volume or weight of liquid contained in a vessel provided its contour characteristic is known. The choice of units, by which the level information is to be expressed is governed by convenience and practicality. As in most process variables, liquid level can be measured directly or inferred. One of the more popular inferrential gages for measuring liquid level is the differential pressure gage frequently known as the Delta-P-System. This device is adequate for many simple applications but has difficiencies where a gage is required to provide information for a complex control system requiring extremely high accuracies and fast responses. | Ultrasonic Gaging of Cryogenic Liquids | 10.1007/978-1-4757-0540-9_35 |
1960-01-01 | Fundamental studies of the basic nature of radiation effects have been conducted in the Oak Ridge National Laboratory graphite reactor by the Low Temperature Group of the Solid State Division. It was discovered that many radiation induced defects were not observed at room temperature because they thermally anneal at much lower temperatures. Measurements of radiation induced changes in electrical resistivity, yield stress, and stored energy in copper and aluminum single crystals were made at sample temperatures as low as 15°K. Subsequent annealing studies show that about 50 per cent of the change in electrical resistivity is recovered between 28 and 50°K. This appears to be the result of radiation induced defects escaping from low energy traps.^1,2 It is particularly advantageous, when measuring electrical resistance of these metals, to be able to bombard them below 20°K because the change of resistance with temperature is small for many metals in this temperature region. | Liquid Helium Temperatures in an Atomic Reactor | 10.1007/978-1-4684-3105-6_19 |
1960-01-01 | During the past several years, interest has grown tremendously in more efficient thermal insulations for cryogenic applications. The requirements of minimum weight and size as well as efficient operation have placed severe demands on insulation in many of the systems using liquid oxygen. Even more stringent requirements must be met when lower-temperature liquids are handled. Newly designed missile engines utilizing liquid hydrogen, and the use of liquid helium in solid state electronic devices, are examples of applications where improved insulating efficiencies are required. | Low-Temperature Insulating Systems | 10.1007/978-1-4757-0537-9_20 |
1960-01-01 | The design of any airborne device requires the most efficient use of materials of construction as well as the selection of the most suitable materials. In the design of missiles this problem is made most acute by two factors: (1) every ounce of excess weight exacts a tremendous penalty in reduced performance and (2) the temperature environment, while roughly predictable, generally changes through a wide range, and very rapidly. While a great deal of data are available in the published literature with which to predict the performance of materials of construction at various elevated and low temperatures, emphasis in the past has always been on long-time exposures. Using such data for the design of a missile would most certainly mean over-design, and reduced performance because of the excess weight. | Mechanical Testing of Aluminum Weldments | 10.1007/978-1-4757-0540-9_9 |
1960-01-01 | The design of a plant for the liquefaction of gases at extremely low temperatures can be investigated with many-variations in cycle arrangements, choice of working fluid, operating pressures and component characteristics. One has the problem of judging the reasonableness of the choices made, In a recent paper Gifford^1 discusses in general terms the requirements for the optimum plant for the liquefaction of parahydrogen, pointing out that: 1) Vapor cycle refrigeration should be used for cooling to approximately 140°K. 2) Expansion device refrigeration should be used for cooling from approximately 140°K to lower temperatures. 3) Care should be exercised to avoid use of refrigerants generated at low temperature for cooling at a much higher temperature. 4) As many steps of refrigeration levels should be used as is feasible. 5) Great care should be taken to optimize the system for the cooling below 80°K since most of the compressive work will be required there. | Preliminary Design Studies of Low Temperature Refrigeration Plants | 10.1007/978-1-4684-3105-6_3 |
1960-01-01 | An analysis of the requirements for a vehicle capable of travel in space will almost invariably reveal the necessity for cryogenic liquids. Elemental gases such as hydrogen, oxygen, and fluorine constitute the ultimate in high-energy chemical propellant systems and are certain to play a prominent role in the coming generation of space craft. Future propulsion systems such as nuclear rocket power plants will continue to rely on hydrogen for its low molecular weight and high specific heat. Manned vehicles must also include a supply of oxygen in combination with an inert gas such as nitrogen or argon for breathing purposes. | Cryogenic Tankage for Space Flight Applications | 10.1007/978-1-4757-0537-9_11 |
1960-01-01 | In using the technique of overlaying a metal componen with some other material in order to capitalize on certain surface properties (e.g., low frictional coefficient) possessed by the material, but lacking in the metal, one of the major problems to be encountered is that of satisfactory attachment. Research in the field of adhesive bonding has provided considerable knowledge and many products which are usable at elevated temperatures, but very little data exist concerning bonds operating at temperatures much below -65° F. In particular, the satisfactory attachment of a Teflon facing to a metal part for cryogenic application introduces several unique problems, arising primarily from the extraordinary properties possessed by Teflon. These include a thermo-expansivity 10 to 15 times that of most metals, complete chemical inertness to all but a few substances, and the ability of the surface to resist sticking to nearly all normally adhesive materials. | Bonding Plastic to Metal for High Strength at Low Temperatures | 10.1007/978-1-4757-0540-9_10 |
1960-01-01 | When an examination is made of rocket engine propellants which are characterized as high performance in value, it is apparent that these are dominated by fluids which are characterized as cryogenic in nature. Table I compares characteristic velocity values for some high-performance propellant combinations with some present-day propellant combinations. These high-energy propellants produce low-molecular-weight exhaust products at high combustion temperatures and the best propellant systems include the use of liquid hydrogen as the fuel. Table I clearly illustrates that the use of hydrogen as a nuclear fuel when heated to even relatively low temperature far exceeds the performance expectations of the best high-performance chemical propellant systems. Liquid hydrogen is employed instead of gaseous hydrogen because the increased density of the liquid reduces size and weights of storage tanks. | Facilities for Testing Rocket Engine Components Using Cryogenic Fluids as Propellants | 10.1007/978-1-4757-0537-9_14 |
1960-01-01 | Papers presented at previous cryogenic engineering conferences by this company^1, 2, 3 described the principles and many of the applications of the Norelco gas refrigeration machine in the range of 70° to 190° K. The objectives of this paper are twofold: 1) To describe extensions to the design of the present machine which will allow the production and accurate control of temperatures in the range of 90°to 250° K by means of a circulating cold gas. 2) To illustrate applications in test facilities and in industry where the modified Norelco refrigerator can be utilized efficiently and economically. | Ultra Low Temperature Production and Control in Environmental Testing and Application Facilities | 10.1007/978-1-4757-0540-9_14 |
1960-01-01 | The usefulness of low temperature mechanical testing in helping to solve various problems related to the strength and ductility of metals has been generally recognized in the academic fields and by those actually engaged in cryogenic engineering. However, its usefulness is relatively unknown in the general field of engineering, A summary of low temperature mechanical property investigations being conducted at the Westinghouse Research Laboratories is presented to illustrate the general usefulness of this type of work. In addition, this paper is intended to report on the service performance characteristics of low temperature testing apparatus which was proposed at the 1954 Cryogenic Engineering Conference. | The Performance Characteristics of Low Temperature Tension Testing Apparatus and Its Application in Industry | 10.1007/978-1-4684-3102-5_23 |
1960-01-01 | As a result of the rapid increase of technical literature in general and the exceptionally rapid growth of the cryogenic field in particular, ordinary library techniques have become inadequate for rapid retrieval of specific information. A number of storage and retrieval systems [1–4] have been devised for large-scale handling of specialized technical literature. Manual punch cards have been found suitable for up to 10,000 to 20,000 listings, using either a library type of classification system or a “descriptor” alignment system [5,6].Machine handling methods using punch cards, punched tape, and/or magnetic tape have been developed for handling up to 1,000,000 listings and more. All these systems are relatively new and are rapidly being developed and improved. | The Cryogenic Data Center | 10.1007/978-1-4757-0537-9_66 |
1960-01-01 | Neon, which has a normal boiling point of 27.24° K, is a possible cryogenic fluid for the region above liquid helium and hydrogen and below liquid nitrogen. Neon has a relatively high refrigerating capacity at low temperatures and is chemically inert. For temperatures approaching the boiling point of hydrogen, it is a safe and attractive refrigerant. | Thermodynamic Properties of Neon | 10.1007/978-1-4757-0540-9_4 |
1960-01-01 | This and the following paper are progress reports in our continuing study of the catalyzed conversion of ortho and parahydrogen. Last year^1 we presented some converter design data based on experiments with a new hydrous ferric oxide gel catalyst. These data consisted of space velocity versus conversion curves for ortho to para conversions at various temperatures, two feeds, liquid and vapor phase, and gave a comparison between results obtained under approximately isothermal and adiabatic conditions. | Flow Conversion Kinetics of Ortho and Parahydrogen | 10.1007/978-1-4757-0540-9_25 |
1960-01-01 | The so-called temperature stratification phenomenon, which has been observed in containers of cryogenic fluids under certain conditions, is of sufficient interest in the field of cryogenic engineering to warrant special investigation. Areas in which the results of such research may be applied profitably include those concerning the transfer of liquefied gases by pres sur ization, the transfer of liquefied gases by pumping, and the sealed storage of liquefied gases. In the first case, the stratification of contents in a vessel used to supply transfer fluid permits the utilization of subcooled liquid, whose properties are desirable from the aspect of single-phase flow characteristics. In the second case, stratification provides a means to attain, and sustain, net positive suction head for transfer by pumping, the absolute magnitude of NPSH required here depending upon both fluid and pump characteristics. For the final case, the effect of stratification is undesirable, generally, due to the accompanying promotion of an excessive rate of pressure rise in the storage vessel ullage space; the unde sir ability is pronounced for sealed “no-ioss” transport containers in which the maximum time permissible in transit is a direct function of the container design pressure. | An Experimental Study Concerning the Pressurization and Stratification of Liquid Hydrogen | 10.1007/978-1-4757-0537-9_56 |
1960-01-01 | When we began, about 8 years ago, to work specifically on exceedingly high-quality insulations, the best commercially available insulating systems consisted of powders such as perlite or Santocel in vacuum, having an apparent thermal conductivity of approximately 1 · 10^-3 Btu/hr-ft- °F between -300 and 70°F. Of the three modes of heat transport in these vacuum insulations, gaseous conduction, because of the very fine particulate size of the subject powders, is ail but eliminated, even at moderate vacuums. The remaining problem was then one of minimizing the other two modes, solid conduction and radiation. | Characteristics and Applications of Some Superinsulations | 10.1007/978-1-4757-0537-9_24 |
1960-01-01 | In the design and construction of containers for low temperature liquefied gases, the primary effort is usually-directed at minimizing heat transfer to the cold liquid. Designs where other factors are more important still endeavor to obtain minimum heat leak consistent with the other more significant considerations. | Some Methods for Reducing Heat Leak Through Support Members in Liquefied Gas Storage Vessels | 10.1007/978-1-4757-0540-9_36 |
1960-01-01 | The development of the liquid hydrogen bubble chamber as a detector of high energy charged particles comes as a natural outgrowth of the work done by D. A. Glaser. Glaser’s work showed by experiment^1 and theory^2 that an ionizing particle passing through a superheated liquid leaves a track made up of bubbles, which are initiated by fluctuations of energy along the path. Hydrogen was selected as one possible bubble chamber fluid because of its high proton density and the interest in the interactions between charged particles in motion and protons at rest. Hildebrand and Nagle, at the University of Chicago, showed that liquid hydrogen was radiation sensitive.^3 | Performance of a Piston-Expanded Bubble Chamber | 10.1007/978-1-4757-0540-9_37 |
1960-01-01 | Cryogenic fuels, oxidants, and inert working fluids are important to propulsion systems for missiles. Turbopumps for handling these fluids may have bearings, seals, and other parts lubricated by the cryogenic liquids. The physical and chemical properties of most cryogenic liquids of interest are such that they might be expected to have very poor lubricating ability. It is therefore advantageous to utilize compatible slider materials in these cryogenic liquids. | Wear and Friction in Liquid Nitrogen with Austenitic Stainless Steel Having Various Surface Coatings | 10.1007/978-1-4757-0540-9_6 |
2024-03-01 | This paper presents a single-step automatic tuning procedure and an estimator of key parameters of the drill-string system used in deep drilling applications. It is aimed at precise tuning of an external vibration suppression system based on speed control loop of the drilling electrical drive tuned for “stiff” motor-side speed control (the so-called speed source behavior), and the external drill-string torque feedback used for torsional vibration active damping. The automatic tuning procedure is carried out for the case when the drill-string and drill-bit are hoisted from the bottom of the well and the drilling electrical drive briefly enters the limit cycle oscillatory behavior under stiff speed control. The proposed auto-tuning system features a suitable control-oriented process model of the torsional oscillator and a modified-mixer phase detector phase locked-loop equipped with adaptive second-order generalized integrator (band-pass filter) for the extraction of key features of the drive resonance mode. The overall control system design relies on the so-called damping optimum criterion which guarantees a desired level of closed-loop system damping. The functionality of the proposed adaptive control system with automatic tuning of the control strategy has been systematically verified by means of comprehensive simulations, and the effectiveness of the drill-string parameter estimator has also been confirmed using the previously recorded field data to illustrate its robustness in the presence of realistic measurement noise. | Single-step auto-tuning of external active damping control strategy for a drill-string speed-controlled electrical drive | 10.1007/s11081-023-09799-8 |
2024-03-01 | The large integration of renewable energy sources into power systems causes frequency fluctuation, low-frequency oscillations, and deterioration in power system stability. High penetration of wind and solar power also causes a high-frequency nadir and a high rate of change of frequency (ROCOF) after large disturbances. This paper presents a novel simultaneous power oscillation damping and frequency control in grid-connected AC microgrid while taking into consideration of the imperfect communication medium. The coordinated approach-based control scheme is used to enhance the frequency response as well as damping of low-frequency oscillations while maintaining the voltage and frequency in the prescribed range considering renewable uncertainties. In this proposed composite control, the power oscillation damping controller (POD) is based on reactive power modulation, whereas the frequency controller is based on active power modulation. The proposed POD and frequency controller is coordinated with the Linear Quadratic Gaussian (LQG) robust controller to enhance stability and mitigate the communication effect, noise, and time delay. The performance of the composite control scheme is compared by simulation of a grid-connected AC Microgrid by using MATLAB/Simulink software. The simulation result demonstrates the performance of the proposed controller over conventional droop controller for large power flow under different operating conditions, under\over frequency events, and under imperfect communication medium. Such grid support performance is expected to earn new revenue creating opportunities for AC microgrids. | Simultaneous Power Oscillation Damping and Frequency Control in AC Microgrid Considering Renewable Uncertainties: A Coordinated Control of Multiple Robust Controllers with Imperfect Communication | 10.1007/s40998-023-00649-y |
2024-03-01 | In this paper we would like to address the classical optimization problem of minimizing a proper, convex and lower semicontinuous function via the second order in time dynamics, combining viscous and Hessian-driven damping with a Tikhonov regularization term. In our analysis we heavily exploit the Moreau envelope of the objective function and its properties as well as Tikhonov regularization properties, which we extend to a nonsmooth case. We introduce the setting, which at the same time guarantees the fast convergence of the function (and Moreau envelope) values and strong convergence of the trajectories of the system to a minimal norm solution—the element of the minimal norm of all the minimizers of the objective. Moreover, we deduce the precise rates of convergence of the values for the particular choice of parameters. Various numerical examples are also included as an illustration of the theoretical results. | A fast continuous time approach for non-smooth convex optimization using Tikhonov regularization technique | 10.1007/s10589-023-00536-6 |
2024-03-01 | Testing wave energy converters in the ocean could be expensive and complex, which necessitates the use of numerical modeling. However, accurately modeling the response of wave energy converters with high-fidelity simulations can be computationally intensive in the design stage where different configurations must be considered. Reduced-order models based on simplified equations of motion can be very useful in the design, optimization, or control of wave energy converters. Given the complex dynamics of wave energy converters, accurate representation, and evaluation of relative contributions by different forces are required. This effort is concerned with a performance characterization of the hydrodynamic response of an oscillating surge wave energy converter that is based on a reduced-order model. A state-space model is used to represent the radiation damping term. Morison’s representation of unsteady forces is used to account for the nonlinear damping. Wave tank tests are performed to validate simulations. A free response simulation is used to determine the coefficients of the state-space model. Torque-forced simulations are used to identify the coefficients of the nonlinear damping term for different amplitudes and wave frequencies. The impact of varying these coefficients on the response is investigated. An assessment of the capability of the model in predicting the hydrodynamic response under irregular forcing is performed. The results show that the maximum error is 3% when compared with high-fidelity simulations. It is determined that the nonlinear damping is proportional to the torque amplitude and its effects are more pronounced as the amplitude of the flap oscillations increases. | Performance characterization and modeling of an oscillating surge wave energy converter | 10.1007/s11071-023-09248-2 |
2024-03-01 | Considering the limited research on the dynamic properties of silty soil treated with biological enzymes, this study aimed to investigate the effects of enzyme content, confining pressure, and loading frequency on the dynamic properties of bio-enzyme-modified silty soil. Nonlinear equations were established for the dynamic elastic modulus, damping ratio, and dynamic strain of the enzyme-improved silty soil through a series of dynamic triaxial tests conducted under fractional loading. The results demonstrate an approximately hyperbolic shape in the dynamic backbone curve of the enzyme-improved silty soil. When the enzyme content is equal to or less than 0.010%, the skeleton curve of the improved soil is significantly affected. With an increase in confining pressure, the backbone curve displays an evident upward trend. Loading frequency exhibits minimal influence on the dynamic stress–strain relationship of silty soil improved by biological enzymes. At an enzyme content of 0.010%, the dynamic elastic modulus of the silty soil reaches its maximum value. As the confining pressure increases, the dynamic elastic modulus of the bioenzyme-improved silty soil gradually increases and tends to stabilize. Loading frequency has little effect on the dynamic elastic modulus of the improved soil. When the loading frequency is lower than 1.5 Hz, the damping ratio of the improved soil decreases with increasing frequency. Conversely, when the loading frequency exceeds 1.5 Hz, the damping ratio amplifies with higher frequencies. | Research on the Dynamic Elastic Modulus and Damping Ratio of Silty Soil Improved by Bioenzyme | 10.1007/s10706-023-02632-0 |
2024-03-01 | In this paper, we introduce the numerical study of the stochastic Duffing-Van der Pol equation under both multiplicative and additive random forcing. The study involves the use of the Wiener-Chaos expansion (WCE) technique and the Wiener-Hermite expansion (WHE) technique. The application of these techniques results in a system of deterministic differential equations (DDEs). The resulting DDEs are solved by the numerical techniques and compared with the results of Monte Carlo (MC) simulations. Furthermore, we introduce a formula that facilitates handling the cubic nonlinear term of the polynomials Chaos. From the study, we do not only demonstrate the accuracy and ease of the WCE technique to solve the cubic nonlinear stochastic differential equations, but also, show the physical understanding of the dynamical behavior of the stochastic solutions through its statistical properties. Moreover, we investigate the WCE of the cubic term in the equation, the influence of the damping coefficients and the external force coefficient on both the used techniques and the behavior of the solution. | Numerical solutions of stochastic Duffing-Van der Pol equations | 10.1007/s13226-022-00361-3 |
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