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2000-01-01 | The Cryogenic Storage and Propellant Feed System (CSPFS) of the space propulsion systems needs to provide propellant in controlled amounts during engine burns of variable duration. Thus, lines connecting the CSPFS to the engine/thruster will be subjected to cyclic cooling and heating. Here we present a model for cryogen transfer line chill-down rate. The model is based on an energy balance involving heat transfer from the outside to the pipe wall, from the wall to the flowing fluid, and energy depletion in the wall. The Morgan correlation is used for the outside heat transfer coefficient, h_a. For the inside heat transfer coefficient, h_fb, correlations of Giarrantano et al. , Hendricks et al. , and Ellerbrock et al. are examined. Our model fit the literature data best when Giarrantano et al. ’s superposition approach is used for h_fb. Even better agreement is obtained when this correlation is modified to account for convective heat transfer overestimation and pipe surface effect on heat transfer. | Modeling of Cryogenic Transfer Line Cool Down | 10.1007/978-1-4615-4215-5_34 |
2000-01-01 | KEKB (KEK B-Factory) is a double-ring electron-positron collider used for studies of CP-violation and other topics on decays of B mesons. Because of the high beam current of KEKB, installation of superconducting cavities has been proposed for the KEKB, and 4 niobium single-cell superconducting cavities were installed in the KEKB ring in the summer of 1998. For cooling of these cavities, an existing cryogenic system with a capacity of 8 kW at 4.4 K and helium transfer lines, which were constructed and used for TRISTAN superconducting cavities, were reused. In this system newly developed, high performance, sub-transfer lines cooled with 80 K liquid nitrogen thermal shields were chosen and constructed to connect the cavity cryostats with the main transfer line. The operation of the complete system for the commissioning of KEKB was initiated at the end of 1998. This paper describes the cryogenic system and the operating experience gained during the commissioning. | Cryogenic System for KEKB Superconducting RF Cavities | 10.1007/978-1-4615-4215-5_50 |
2000-01-01 | A collaborative effort between the National High Magnetic Field Laboratory (NHMFL) and Maxdem Incorporated has been undertaken to evaluate two high strength polymers for use in cryogenic and magnet applications. The polyphenylene based thermoplastic materials (henceforth referred to as Parmax−1000 and Parmax−1200) are un-reinforced polymers, fabricated by Maxdem Incorporated using powder compression molding techniques. Two other forms of Parmax−1200 were also characterized; one with a plasticizer addition, and the other with chopped, high strength fibers added. The tests were conducted to generate mechanical and thermal property data at 295, 77 and 4K. The properties measured at the NHMFL and reported here are tensile, compressive, flexural strengths. The test results at room temperature show the strength of both unreinforced polymers are approximately three times greater than conventional thermoplastics with a modulus twice as great. The observed 4K tensile strength is approximately half that of other conventional thermoplastics. The materials have relatively low thermal contraction which at 4K is approximately half the value of epoxy resins and is comparable to that observed for NEMA G-10 glass reinforced laminates. The addition of plasticizer and high strength fibers into the Parmax−1200 matrix has led to strength results slightly lower than expected. These data represent some of the first attempts to modify the materials and although the plasticizer addition caused a slight drop in strength the improved processibility may be worthwhile tradeoff. The fiber addition improves elastic properties but decreases strength which is attributed to fiber-matrix interface bonding. | Mechanical and Thermal Properties of Unreinforced and Reinforced Polyphenylenes at Cryogenic Temperatures | 10.1007/978-1-4615-4293-3_19 |
2000-01-01 | In 1998 the first energy upgrade of the LEP Electron/Positron collider, LEP2, was completed at CERN. Sixty-eight superconducting modules supplied by four 12 kW @ 4.5 K equivalent power refrigerators have been operated allowing a colliding beam energy of 94.5 GeV. Meanwhile, the operation and maintenance responsibilities were transferred to an industrial firm on the basis of a result-oriented contract. After a short description of the operational organization, we report on the operation of the LEP2 cryogenic system over the past three years. Particular attention is given to power availability, failure statistics and recovery time after interruptions. The most relevant problems and their solutions are exposed. Finally, we review the interactions between the cryogenic system and the particle beams, which are limiting the ultimate performance of the LEP collider. | Operation of the Four 12 KW at 4.5K Refrigerators for LEP | 10.1007/978-1-4615-4215-5_43 |
2000-01-01 | Large projects based on applied superconductivity, such as particle accelerators, tokamaks or SMES, require powerful and complex helium cryogenic systems, the cost of which represents a significant, if not dominant fraction of the total capital and operational expenditure. It is therefore important to establish guidelines and scaling laws for costing such systems, based on synthetic estimators of their size and performance. Although such data has already been published for many years, the experience recently gathered at CERN with the LEP and LHC projects, which have de facto turned the laboratory into a major world cryogenic center, can be exploited to update this information and broaden the range of application of the scaling laws. We report on the economics of 4.5 K and 1.8 K refrigeration, cryogen distribution and storage systems, and indicate paths towards their cost-to-performance optimisation. | Economics of Large Helium Cryogenic Systems: Experience from Recent Projects at CERN | 10.1007/978-1-4615-4215-5_44 |
2000-01-01 | The Chemical Propulsion Information Agency (CPIA) and Technology Applications, Inc. (TAI), in collaboration with the National Institute of Standards and Technology (NIST), has reconstructed and updated the database of the former National Bureau of Standards (NBS) Cryogenic Data Center. NBS maintained a database of cryogenic technical documents that served the national need until the early 1980s. The electronic database, maintained on a mainframe computer, was a highly specific bibliography of cryogenic literature and thermophysical-property data that covered 100 years of data. However, since then, the database has not been maintained for use. We have undertaken a project to convert the NBS database to a personal-computer (PC) platform and to backfill the database with citations of cryogenic literature dating from 1980 up to the present. Our first CD-ROM release of the reconstituted and updated retrieval system contained about 126,000 citations; 115,000 of them represent bibliographic entries from the former NBS database, and over 11,000 represent new citations with abstracts from recent literature. The retrieval system contains a new search engine with formatted printing capabilities. Semiannual releases of currently updated CD-ROMs are planned. An additional on-going activity involves development of a database consisting of computer codes for generating thermophysical properties of cryogens and materials. Our objective for this task is to develop “user-friendly” standard properties of fluids and materials of databases traceable to NIST so that the government and industry can conduct and compare analyses using the same properties. | Cryogenic Technology Information Database Program | 10.1007/978-1-4615-4215-5_29 |
2000-01-01 | The Large Hadron Collider (LHC), presently under construction at CERN, will require a helium cryogenic system unprecedented in size and capacity, with more than 1600 superconducting magnets operating in superfluid helium and a total inventory of almost 100 tonnes of helium. The objective of the Preliminary Risk Analysis (PRA) is to identify all risks to personnel, equipment or environment resulting from failures that may accidentally occur within the cryogenic system of LHC in any phase of the machine operation, and that could not be eliminated by design. Assigning a gravity coefficient and one analyzing physical processes that will follow any of the recognised failure modes allows to single out worst case scenarios. Recommendations concerning lines of preventive and corrective defence, as well as for further detailed studies, are formulated. | Preliminary Risk Analysis of the LHC Cryogenic System | 10.1007/978-1-4615-4215-5_45 |
2000-01-01 | The dielectric strength of vacuum insulation is reduced considerably when high voltage electrodes are bridged by solid insulation. Further reduction of strength can occur when the solid material outgases as in the case of fiber reinforced plastics (FRP). Even when the overall vacuum is acceptable, the higher gas pressures near the insulator surface can result in unacceptably low hold- off strengths. For superconductor applications in high voltage power equipment the problem of outgassing may be reduced or eliminated by the low temperatures employed. We will report on ac and impulse surface flashover studies of two types of fiberglass reinforced epoxy composite insulators, G-10 and G-11, at ambient temperature and at low temperature, using liquid nitrogen cooled electrodes, at vacuum pressures below l.0x10^−6 Torr (1.3x10^−4Pa). Also, AC and impulse breakdown voltages for a pure vacuum gap are compared to the gap breakdown voltages obtained for the electrode-insulator-electrode arrangement. In addition, preliminary results on the effect of orientation of the layers in G-10 and G-11 on breakdown, surface flashover, and puncture are also presented. | Surface Flashover of Fiberglass Reinforced Epoxy Composite Insulation in Vacuum at Liquid Nitrogen and Room Temperatures using Power Frequency AC and Lightning Impulse Waveforms | 10.1007/978-1-4615-4293-3_38 |
2000-01-01 | Reliability is discussed during long-term operations of the cryogenic system for the Large Helical Device (LHD). The cooled objects of LHD are the helical coils, the poloidal coils, the supporting structure and the superconducting bus lines. The cryogenic system, which permits complicated cooling schemes for each cooled object, was designed to focus on the reliable long-term operation. Impurities in the helium gas should be controlled carefully to prevent a blocking of filters, malfunction of control valves and deterioration of heat exchanger performance. The first cycle operation of LHD started on February and ended on June in 1998, and the second cycle operation started on August and continued to the end of 1998. The performance during the first and second cycle long-term operations and the precise impurity measurement technique are reported. | Reliable Long-Term Operation of the Cryogenic System for the Large Helical Device | 10.1007/978-1-4615-4215-5_38 |
2000-01-01 | Relict perennial cryogenic mounds, (the remains of pingos or paisas) have long been identified in the UK and have been attributed to the Last Glacial or Younger Dryas cold periods. These features take the form of circular to oval depressions surrounded completely or partially by a raised rim or rampart. The depressions very often contain a wetland with an organic soil or peat. At depth within the depressions there can be up to several metres of soft sediments (very often a silt-clay). The ramparted depressions are usually found in clusters where individual features may overlap such that they share ramparts or even where the depressions merge to produce a ‘figure-of-eight’ shape in plan. Such relict periglacial features are extremely useful for palaeoclimatic reconstruction, since they can indicate the average thermal condition of the ground during the period in which they were actively forming. Many relict cryogenic mounds in the UK have been interpreted as the remains of hydraulic pingos, features which in contemporary cold climate areas indicate either discontinuous permafrost (mean annual air temperature (MAAT) of ≤ -3° C) or continuous permafrost (MAAT of ≤ -7° C). Some of these features, however, have now been re-interpreted as the remains of ‘mineral-cored’ paisas, features that are indicative of only sporadic permafrost (MAAT of ≤ -1° C) or discontinuous permafrost (MAAT of ≤ 3°C). Thus the varying interpretation and classification of these geomorphological features can lead to a wide disparity in their palaeoclimatic significance. Clearly, to obtain the correct palaeoclimatic information, such features must be accurately identified and appropriate modern analogues utilised in their interpretation. | Relict Cryogenic Mounds in the UK as Evidence of Climate Change | 10.1007/0-306-48086-7_11 |
2000-01-01 | The installation, initial cooldown, and cryogenic testing of the RHIC accelerator magnets and cryogenic system are complete. This paper covers the final phase of cryogenic equipment installation, performance of the system during the first accelerator cooldown, and difficulties encountered with cooling and commissioning. The 25 kW refrigerator, although operated for limited time periods in the past, has been running continuously for months. Operational experiences of the refrigerator and warm compressor systems will be discussed. | RHIC Accelerator Commissioning, Cryogenic Tests and Initial Operating Experience of the 25 kW Refrigerator and Distribution System | 10.1007/978-1-4615-4215-5_47 |
2000-01-01 | The cryogenic system of the large superconducting solenoid magnet for the BELLE detector system was constructed at KEK for B-meson physics. This system consists of a refrigerator, compressor and buffer tank, which were previously used and reassembled, and a recovery tank, subcooler and superconducting solenoid magnet, which were newly constructed. The cryogenic system is automatically controlled and operated from cool down to warm up according to programmed steps. It is monitored on the World Wide Web. The magnet is indirectly cooled by forced, two-phase, helium flow during steady state operation. In the case of an emergency stop of the refrigerator, the cooling method is switched to a thermo-syphon mode by an automatic process control. In the cooling test, the refrigeration power was 240 W at 4.4 K, which was almost the same as the previously measured value before reassembling, and the heat leakage into the magnet was deduced to be 31.8 W. After performance tests and two operations to tune the detectors, regular operations with the colliding beam started for the first time in May 1999. | Cryogenic System of a Superconducting Solenoid Magnet for the Belle Detector System in KEK | 10.1007/978-1-4615-4215-5_48 |
2000-01-01 | High performance transfer lines are key components for design and construction of cryogenic systems for superconducting magnets and cavities. We have developed two types of high performance transfer lines; main transfer lines with liquid helium flow and cold gas return dual path and sub-transfer line with single path, all helium lines in these are guarded by 80K liquid nitrogen cooled thermal shields. We have adopted the aluminum molding made by extrusion for the 80K thermal shields. The structure of the transfer lines was designed to be easy to assemble. The performance of these transfer lines were tested. The heat loss of the main transfer lines at straight section are 0.04W/m and 0.06W/m for supply and return line, respectively. | Development of a High Performance Transfer Line System | 10.1007/978-1-4615-4215-5_56 |
2000-01-01 | The Large Helical Device (LHD), an experimental fusion apparatus, has conducted a second experiment cycle. The infrastructure of the LHD cryogenic control system (TESS) is a combination of a distributed control system with an integrated controller linked by multiple LANs. The integrated controller shares information with four subsystems: the helium refrigerator/liquefier, the helical coil, the poloidal coil and the superconducting busline, via reflective memories. Each subsystem has a VME bus and a workstation for process control and programming. Cooldown processes of each subsystem are implemented independently by the temperature levels. Sequence programs are developed to change cooling modes for subsystems corresponding to their temperatures. Program Control Units (PCUs) proceed cooldown and warmup process in terms of gaseous-helium supply temperature and mass-flow rates. Temperature distributions in the subsystems are monitored and process will be interrupted if temperature gradients exceed 50 K. In the case of coil quench, emergency sequence programs are executed to prevent any damage to the apparatus. The paper describes the performance of LHD-TESS during cooldown, steadystate operation, and the case of emergencies. | LHD Cryogenic-Control System Performance Under Various Operating Conditions | 10.1007/978-1-4615-4215-5_49 |
2000-01-01 | Ongoing progress in manufacturing dielectric ceramics and single crystals with high dielectric constant and low microwave losses has turned out to be a challenge for the development of novel devices for satellite communication. From this development device performance is expected to benefit for possible device operation temperatures ranging from cryogenic temperatures around 50 — 150 K (achievable with one-stage close cycle refrigerators) over temperatures from 150 to 20OK (in principal achievable with radiation cooling) towards room temperature, if novel dielectric resonator structures with lower loss contribution of the metallic housing would become available. | Novel Cryogenic Dielectric Resonator Devices for Satellite Communication | 10.1007/978-4-431-66877-0_310 |
2000-01-01 | High-temperature superconducting (HTS) cable systems for power transmission are under development that will use pressurized liquid nitrogen to provide cooling of the cable and termination hardware. Southwire Company and Oak Ridge National Laboratory have been operating a prototype HTS cable system that contains many of the typical components needed for a commercial power transmission application. It is being used to conduct research in the development of components and systems for eventual commercial deployment. The cryogenic system was built by Air Products and Chemicals, Allentown, Pennsylvania, and can circulate up to 0.35 kg/s of liquid nitrogen at temperatures as low as 67 K at pressures of 1 to 10 bars. Sufficient cooling is provided for testing a 5-m-long HTS transmission cable system that includes the terminations required for room temperature electrical connections. Testing of the 5-m HTS transmission cable has been conducted at the design ac conditions of 1250 A and 7.5 kV line to ground. This paper contains a description of the essential features of the HTS cable cryogenic system and performance results obtained during operation of the system. The salient features of the operation that are important in large commercial HTS cable applications will be discussed. | Cryogenic System for a High-Temperature Superconducting Power Transmission Cable | 10.1007/978-1-4615-4215-5_58 |
2000-01-01 | A key feature of the cryogenic system for the proposed TeV Superconducting Linear Accelerator (TESLA) is a He II two-phase flow line that provides cooling for the superconducting RF cavities. Understanding the behavior of this line is vital to the proper functioning of the accelerator. A numerical model has been developed that allows predictions of the pressure, temperature and mass flow rates of the components in the twophase line and in the connected gas return line. The model also predicts the helium level in the two-phase line. This is a rigorous model using the conservation laws of mass, momentum and energy for each phase and allowing for interactions between the phases and the walls as well as between each other. The model also takes into account the specific geometry of the TESLA cooling system. This paper describes the model and presents its predictions for two alternative cooling schemes. | Numerical Study of Two-Phase Helium II Stratified Channel Flow | 10.1007/978-1-4615-4215-5_6 |
2000-01-01 | A thermoelectric element, known as a Peltier element, is evaluated as a heat flux sensor at cryogenic temperature. Several commercially available Peltier elements were tested at 77 K to detect heat flux generated by the heater. Preliminary experimental results show that an output voltage of the Peltier element is nearly 10 times larger than that of the same-size conventional heat flux sensor at 77 K. It implies a possible use of the Peltier element as a heat flux sensing device for cryogenic applications. This element can be used as a kind of in situ sensor for radiant heat flux measurement. Also, it will be a strong tool for investigation of insulation techniques, e.g. performance check at the overlapping part of multi-layer insulation etc. A newly developed heat meter was used to calibrate the heat flux through the Peltier element. It is made of a thermal resistance material (stainless steel: SS), sandwiched by the oxygen free copper block by using the HIP (hot isostatic pressing) method. | Peltier Heat Flux Sensor for Cryogenic Use | 10.1007/978-1-4615-4215-5_120 |
2000-01-01 | CMOS-based computer processors will operate at increased frequencies when cooled to sub-ambient temperatures by a refrigeration system. This benefit must be weighed against many refrigerator considerations, the most noteworthy being thermal performance, efficiency, reliability, and cost. With this in mind a throttle-cycle, mixed-refrigerant cryocooler using a single-stage, oil-lubricated compressor was modified for increased capacity at 173K (-100°C) and its thermal performance was characterized. This mixedrefrigerant system cooled 119 Watts (with an average heat flux of better than 5 Watts/cm^2) at an interface temperature of 173K, with a Coefficient of Performance (COP) of more than 22%. The maximum in cooling capacity was 140 Watts at 183K (-90°C). The ratio of the COP relative to Carnot (ideal) efficiency held very constant at 16% over the temperature range of 153 to 183K (-120 to -90°C). This performance (relative to Carnot) is comparable to that of refrigeration systems with similar capacity operating at much higher temperatures. These results establish the good efficiency obtainable using mixedrefrigerant technology, making cooled CMOS applications attractive. Based on experimental data and computer simulations, we anticipate that better than 20% of Carnot efficiency can be achieved with a more optimal design. | Performance of a Mixed-Refrigerant System Designed for Computer Cooling | 10.1007/978-1-4615-4215-5_84 |
2000-01-01 | Within the frame work of the VAMAS TWA 17 activity, J evaluation on tensile test (JETT) was performed as an international round robin test. 316LN plate with 30 mm thickness was supplied as a common test material, but it contained irregular microstructure around the center of the plate thickness supposed to be generated during the rolling process. The fracture toughness at 4.2 K according to ASTM standard was invalid because of crack front shape requirement. However, JETT showed the lower toughness at the midsection than that at the near surface part. From this result, it was clarified that the JETT has a potential to evaluate local fracture toughness. Since the material showed serrated deformation during the JETT at cryogenic temperature, the evaluated toughness scattered rather widely, and stiffness of testing machine would affect the results. | Local Fracture Toughness Evaluation of 316LN Plate at Cryogenic Temperature | 10.1007/978-1-4615-4293-3_4 |
1999-10-01 | The solubilities of solid pentane, 2-methylbutane (isopentane), and cyclopentane in liquid argon at 87.3 K have been measured by the filtration method. The C_5 hydrocarbon content in solution was determined using gas chromatography. The solubilities of the C_5 hydrocarbons in liquid argon at 87.3K vary from 0.61 × 10^−7 mole fraction for cyclopentane, to 1.37 × 10^−7 mole fraction for pentane, and 8.83 × 10^−6 mole fraction for 2-methylbutane. The Preston–Prausnitz method was used for calculation of the solubilities of solid C_5 hydrocarbons in liquid argon in the temperature range 84–110 K and in liquid nitrogen in the range 64–90K. The values of the solvent–solute interaction constant l _12 were also calculated. | Solubility of Solid Pentane, 2-Methylbutane, and Cyclopentane in Liquid Argon at 87.3 K | 10.1023/A:1021707826000 |
1999-09-01 | We propose an approach to determination of allowable stresses by a static-strength criterion for materials of structures that operate at very low temperatures (T≤20 K). This approach takes into account the qualitative change in the nature of deformation of the material, which has a significant effect on the mechanical characteristics and the specific work of deformation. The choice of critical stresses for these conditions is substantiated. The calculations are performed by introducing corrections for low-temperature hardening of the material in the presence of the intermittent-flow effect. We discuss the possibility of taking into account the influence of strong magnetic fields on the magnitude of allowable stresses. | Standardization of the strength of metals under conditions of low-temperature instability of plastic deformation and the action of strong magnetic fields | 10.1007/BF02511164 |
1999-08-01 | A thin conductor is used to examine the principle of design of the sensitive element of a transducer for measuring the amount of a liquid randomly distributed in a tank. A method of evaluating the measurement error is proposed and the output characteristic of the transducer is determined. Results are presented from experimental studies. | Principle of the design of the sensitive element of a radiowave transducer for measuring the amount of a liquid randomly distributed in a spherical tank | 10.1007/BF02504358 |
1999-06-01 | An experimental setup, including a cryogenic gas target with temperature control and gas filling systems, has been developed to study muon catalyzed fusion in gas mixtures of hydrogen and helium isotopes. | A cryogenic target to study charge nonsymmetric muonic molecules | 10.1023/A:1012601323424 |
1999-06-01 | A feasible scheme of a cryogenic reactor based on muon catalyzed fusion for an intense 14 MeV neutron source (INS) is considered. | Cryogenic reactor for the INS project | 10.1023/A:1012636903860 |
1999-05-01 | Cryogenic processes in engineering-geologic investigations for water-supply objects in transriverine regions of Central Yakutia | 10.1007/BF02764528 | |
1999-01-01 | Methane | 10.1007/978-1-4615-5285-7_37 | |
1999-01-01 | Ethylene | 10.1007/978-1-4615-5285-7_26 | |
1999-01-01 | Removal of surface contaminants by various cryogenic aerosol jets has been experimentally investigated. Simplified theoretical consideration of their removal mechanism has been also presented based on the impact power of the aerosol jets. Under atmospheric operation, water vapor and carbon dioxide could make their particles independent of their concentrations in the carrier gas while argon and nitrogen could hardly solidify to their own particles. The cryogenic aerosol jets were very effective in removing both submicron particle contaminants and photoresist films on wafers. The rate of the PR film removal strongly depended on the hardness of the film. Molecular organic films could be also removed with the aerosol jets. In general, the removal of the contaminants depends primarily on the physical impact. The removal rate increased with the mass concentration of the aerosol particles, regardless of their nature. The rate also increased with the impact velocity of the jets which was controlled by either the chamber pressure or the distance between the nozzle tip and the contaminant surface. The cryogenic aerosolfree jet was much less effective than the corresponding aerosol jets but had some effectiveness compared to the noncryogenic one. The thermal shock of the film was, therefore, supposed to have a secondary effect on the contaminant removal. | Removal of surface contaminants by cryogenic aerosol jets | 10.1007/BF02699011 |
1999-01-01 | Gases expand uniformly to fill the volume of the container that holds them. | Gases and Class 2 | 10.1007/978-3-662-11890-0_35 |
1999-01-01 | This chapter provides an introduction to compressed gases. Included are descriptions of the various groupings and families into which gases are categorized, as well as information concerning standard units of measurement. This is useful background information especially to anyone unfamiliar with gases. | Compressed Gases Today | 10.1007/978-1-4615-5285-7_1 |
1999-01-01 | Many of the compressed gases produced such as chlorine and ammonia are shipped in bulk containers. Bulk containers are described by the U.S. Department of Transportation (DOT) as containers having a water capacity in excess of 1000 lb (454 kg). The most common types of bulk containers are tank cars, cargo tanks (tank trailers), and portable tanks. Tank ships and tank barges are also considered bulk containers. Practically all types of bulk containers authorized for shipping compressed gases on land are also authorized (under some conditions) for water shipment. They include single-unit tank cars, which are approved for cargo vessels or railroad car ferry vessels; tank trailers, which are approved for cargo vessels and trailerships; and portable tanks, which are specially designed for movement via highway, rail, container-onflatcar (COFC), or ocean vessel. | Bulk Containers for Compressed Gases | 10.1007/978-1-4615-5285-7_6 |
1999-01-01 | Air | 10.1007/978-1-4615-5285-7_13 | |
1999-01-01 | Carbon Monoxide | 10.1007/978-1-4615-5285-7_21 | |
1999-01-01 | Argon | 10.1007/978-1-4615-5285-7_15 | |
1999-01-01 | This chapter describes, with an emphasis on physical principles, satellite-borne instrumentation for cosmic X-ray spectroscopy. Both wavelength dispersive spectrometers and energy dispersive detectors are considered; the potential and problems of new forms of cryogenic detector are examined in particular detail. | Instrumentation for X-ray Spectroscopy | 10.1007/978-3-540-49199-6_7 |
1999-01-01 | Hydrogen Chloride | 10.1007/978-1-4615-5285-7_33 | |
1999-01-01 | This chapter describes and illustrates the major types of containers used to transport and store compressed gases, including those liquefied at very low or cryogenic temperatures. To keep pace with developments in the industry, CGA, through its technical committees, continually reviews and recommends changes to existing container specifications promulgated by the U.S. Department of Transportation (DOT) or Transport Canada (TC). Moreover, new specifications for compressed gas containers are also proposed from time to time. | Compressed Gas Cylinders, Regulators, and Valves | 10.1007/978-1-4615-5285-7_5 |
1999-01-01 | The very properties that make compressed gases and cryogenic liquids useful in almost every area of modern life can also cause hazardous conditions if mishandled. These hazards may vary with the characteristics of the product and how it is stored. Storing gases under high pressure or at cold (cryogenic) temperatures may create a hazard. Gases may be flammable, corrosive, toxic, self-reactive, or cause an explosion. They also may be oxidizing, pyrophoric, or cause asphyxiation. | Safety Considerations for Compressed Gases and Cryogenic Liquids | 10.1007/978-1-4615-5285-7_2 |
1999-01-01 | Nitrogen | 10.1007/978-1-4615-5285-7_43 | |
1999-01-01 | Rare Gases | 10.1007/978-1-4615-5285-7_51 | |
1998-12-01 | Within the last two decades, a number of experimental techniques have been developed to measure mean free paths and absolute and effective cross-sections for various processes related to the interaction of low-energy electrons with condensed matter. In all of the experiments, a monochromatic electron beam impinges on a thin multilayer film composed of atoms and/or molecules condensed on a metal or semiconductor substrate held at cryogenic temperatures in an ultra-high-vacuum system. Depending on the apparatus, cross-sections are obtained from low-energy electron transmission (LEET), high-resolution electron energy loss (HREEL), x-ray photoelectron (XPS) spectroscopy, electron-stimulated desorption (ESD) of neutral and ions, or a combination of these techniques. Quasi-elastic and inelastic mean free paths have been extracted from LEET data. This method has also served to generate absolute cross-sections for electron trapping and fragment production from the dissociation of transient molecular anions. In amorphous ice, a complete set of absolute cross-sections for all inelastic losses by 1–20 eV electrons has been obtained from HREEL data. Effective cross-sections for neutral and ionic radical formation were generated by desorption and XPS experiments. These various methods are briefly described in this article, and the corresponding cross-sections in the range 0–20 eV summarized. | Absolute and effective cross-sections for low-energy electron-scattering processes within condensed matter | 10.1007/s004110050125 |
1998-10-01 | This paper reviews various available powder-synthesis techniques being used in laboratories and industries for the production of high-critical-temperature superconductors. The powder characteristics that are desirable for various components, such as Levitators™, sputtering and laser ablation targets, and conductors (tapes and wires) are discussed. | High-temperature superconductors: Synthesis techniques and application requirements | 10.1007/s11837-998-0346-y |
1998-09-01 | The characteristic features of the continuous-wave lasing spectra near 3.3 µm of multimode InAsSbP/InAsSb/InAsSbP double-heterostructure diode lasers are shown. The observation of mode switching to longer and shorter wavelengths at cryogenic temperatures is reported. It is shown that suppression of the longitudinal side modes closest to the main mode results in large mode jumps in energy during mode tuning by current. The characteristics which were observed are explained by gain spectrum inhomogeneity due to spectral hole burning in narrow-gap semiconductors. The intraband charge-carrier relaxation times in the active region are estimated. | Spectral and mode characteristics of InAsSbP/InAsSb/InAsSbP lasers in the spectral region near 3.3 µm | 10.1134/1.1187537 |
1998-08-01 | The maturity of the gas chromatography technique belies the continuing search for improved operating methods. Cryogenic methods, applied in many forms, have been used for many years to trap volatile compounds in chromatography. Recent work has demonstrated an alternative approach to band accumulation. A small tube incorporating an internal sleeve cooled cryogenically, placed over a gas chromatography capillary column, can be moved back-and-forward over the column to permit collection and remobilization of focused bands. The movement frequency or timing can be altered to give different operational modes and outcomes. Results demonstrate that peaks can be fully accumulated just prior to a detector then rapidly flushed into the detector, allowing considerable increase in peak height as the peak width diminishes. Applications illustrate that all or selected peaks in a chromatogram can be thus modified by the trap. Column bleed can likewise be collected and then re-eluted, leading to a novel presentation of the molecular constituents of the bleed. With multidimensional gas chromatography, heart-cuts from the first column can be trapped and focused at the head of the second column, then rapidly re-injected into the second column leading to certain advantages. Furthermore, by rapid modulation of the cold trap, a single peak can be cut into a series of separate pulses, either into a detector or into a second column. This allows unusual expression of a chromatographic peak profile, and can be incorporated into a comprehensive GC experiment. | Modulation and Manipulation of Gas Chromatographic Bands by Using Novel Thermal Means | 10.2116/analsci.14.651 |
1998-06-01 | The solubilities of 1-pentene ice in liquid nitrogen at a temperature of 77.4 K and in liquid argon at 87.3 K have been measured by the filtration method. The 1-pentene content in solution was determined using gas chromatography. The experimental value of the mole fraction solubility of 1-pentene ice in liquid nitrogen at 77.4 K is: (1.28±0.25)×10^−7 and (4.11±0.44)×10^−7 in liquid argon at 87.3 K. The Preston–Prausnitz method was used for calculation of the solubilities of 1-pentene ice in liquid nitrogen in the temperature range 64.0–90.0 K and in liquid argon in the temperature range 84.0–90.0 K. The parameters l _12 were also calculated. At 90.0 K liquid argon is the better solvent for 1-pentene ice than is liquid nitrogen. | Solubility of 1-Pentene Ice in Liquid Nitrogen and Argon at the Standard Boiling Points of the Solvents | 10.1023/A:1022662020454 |
1998-04-01 | A styrofoam layer is introduced to the cryogenic calibration load for microwave radiometers in order to keep the antenna at ambient temperature while calibrating. Obviously the insulation layer has nonuniform temperature profile. A novel approach based on the transmission-line theory is presented to calculate the emission from the load. According to the sample calculation through this new approach, the contribution of the insulation layer to the load radiation can not be neglected. | Radiation from the cryogenic calibration load for microwave radiometers | 10.1007/s11767-998-0054-3 |
1998-04-01 | Data on the vibrational spectra of noble gas fluorides in the gas phase and in cryogenic and nonaqueous solutions are considered in detail. Based on analysis of the IR spectra of xenon fluorides dissolved in liquid Kr and Xe, it is concluded that the XeF_6 molecule possesses the geometry of a distorted octahedron with C _3v symmetry. The contours of spectral lines of totally symmetric stretching modes in the Raman spectra of noble gas fluorides in nonaqueous solutions are considered; the mechanisms of formation contours of these lines, the dynamic parameters of XeF_ n ( n =2, 4, 6) and KrF_2, and the characteristic times of intramolecular rearrangements in the nonrigid XeF_6 molecule are analyzed. It is concluded that in the XeF_2-HF and XeF_6-HF systems, a number of associates and ionic clusters are formed due to the donor-acceptor interaction of the Lewis bases and acids. | Vibrational spectra and structural features of noble gas fluorides in cryogenic and nonaqueous solutions | 10.1007/BF02495952 |
1998-03-01 | 1. It is necessary to revise urgently SNiP 2.06.05-84x with respect to the designs of dams being constructed in the northern construction-climatic zone, i.e., to remove all vagueness in understanding the basic design principles. 2. The top of watertight zones of dams should exceed the elevation of the HFL by amounts specified by SNiP. When necessary, in connection with seasonal freezing and thawing of the upper part of the core, additional measures should be provided for ensuring local static stability and seepage strength. 3. Large dams should be evaluated under the aegis of the National Committee on Large Dams, whose role in this matter must be increased. It is necessary to establish legislatively the procedure of changing the designs of dams after approving the projects. 4. A coordination center processing all information on construction and operation should be created for large dams and dams being constructed in the northern construction-climatic zone. The best solutions should be recommended for implementation. 5. It is necessary to reconstruct the upper part of the dams of the Kureika hydrodevelopment, using above the NPL soils of an analogous composition for the entire zone of the core with provision of its seepage strength by an additional filter layer of sorted sand of fractions 0–10 mm. Reconstruction of the dam crests will make it possible not only to obtain additional power production due to the prism of the reservoir between the NPL and HFL within 150–200 million kWh/yr. | Contribution to the problem of so-called antiheave heads of crests of dams being constructed in the far north | 10.1007/BF02905897 |
1998-01-01 | The helium refrigeration system that will cool the superconducting magnets of the RHIC machine are discussed. Compressors, refrigerator, gas distribution, storage and handling equipment are summarized, noting the quantity of estimated excess capacity available for use by experimenters. Collaboration between RHIC cryogenics and experimenters interested in helium based turbulence research provides a unique opportunity for the economical utilization of government owned scientific assets. | A Brief Overview of the RHIC Cryogenic System | 10.1007/978-1-4612-2230-9_21 |
1998-01-01 | The Confined Helium Experiment (CHeX) is manifested for flight on the Space Shuttle (STS-87) in November, 1997. The experiment was constrained to re-use a previously flown flight cryogenic system. However, the inherited system did not meet CHeX science requirements, nor current Shuttle launch requirements; enhancements of the system and procedures were required. We present model and data of the full flight system, before and after the enhancements were made. A discussion of procedural changes and their impact on the system are also presented. With the changes, all Shuttle servicing requirements were met. A net improvement in ground servicing of 30% and a net parasitic reduction of 15% were achieved. Predicted flight performance is also presented. | Lifetime Enhancement of the CHeX Cryogenic System | 10.1007/978-1-4757-9047-4_124 |
1998-01-01 | The g-2 Muon storage ring consists of three superconducting solenoids 15 meters in diameter, and a beam Inflector solenoid 1.7 meters in length. All superconducting solenoids are indirectly cooled by forced two-phase helium. Cryogenic cooling is accomplished via a J-T circuit and a LHe control dewar. The control System for this cryogenic system is built around commercially available Programmable Logic Controllers (PLC’s) and cryogenic hardware for monitoring temperature, pressure and flow control. The complexity of this system necessitated the use of a graphical user interface (GUI) which permitted operators to perform monitoring and control functions from a central control room. The graphical interface allowed for rapid operator training and, with the cooling circuit schematic shown graphically they can respond to critical situations promptly. Critical data points on the experiment are logged in the software and historical trends are provided for. Using a software based system allowed for rapid system revisions as they were required. Flow control can be performed manually by the operator or automatically by the software based on linear control algorithms. The system has been in use for two years with successful results. | Cryogenic Control System for the g-2 Muon Ring | 10.1007/978-1-4757-9047-4_104 |
1998-01-01 | The present RHIC cryogenic process control system is a hybrid of centralized and distributed processing. The setup marries together a centralized sub-system that was designed, installed, and in operation since 1984 with six identical distributed sub-systems, whose installation began in 1996 and will be completed in 1998. For the RHIC First Sextant Test, which took place from January 21, 1997 to March 5, 1997, it was necessary to have two new distributed cryogenic control sub-systems installed and tested. During the First Sextant Test, gold ions were successfully injected into the superconducting collider at the 6 o’clock region, where they then traveled down Sextant 4/5, and hit a beam stop at the 4 o’clock region (Figure 1). The 6 o’clock region, 4 o’clock region, and Sextant 4/5 are the locations where the two new distributed sub-systems were installed and tested. The thrust of this paper is to discuss these new installations and the overall cryogenic control system performance during the First Sextant Test. | Performance of the RHIC Cryogenic Control System During the First Sextant Test | 10.1007/978-1-4757-9047-4_63 |
1998-01-01 | Experiments have been conducted with two type of gas lubricated foil journal bearings and a small cryogenic turboexpander. One of these bearings is named as a spirally-wound foil bearing and the another is named as a multi-leaves foil bearing. Both of them have much simpler construction and lower cost as compared with the conventional foil bearings. The rotor of cryogenic turboexpander, 103 mm long and weighing 0.9 N, has the working speed up to 230,000 rpm. The main purpose of the investigation is a preliminary examination of stabilizing characteristics of those foil bearings under several different clearances and foil stiffness as well as the durability of the foils. Experimental results indicate the foil bearings presented here offer system stability and high durability, and it confirmed that the application of gas foil bearing to the cryogenic turboexpander is feasible and hopeful. | A Feasibility Study on the Use of New Gas Foil Bearings in Cryogenic Turboexpander | 10.1007/978-1-4757-9047-4_81 |
1998-01-01 | Mechanical properties of zirconia and silica have been measured at cryogenic temperatures. To answer the demands for structural and/or insulation materials in a large scaled superconducting magnet, the ceramic materials were examined. Mechanical properties of certain ceramics such as zirconia, were confirmed to increase at cryogenic temperatures compared with those at room temperatures. Although silica has been widely used as the reinforcement of glass fiber reinforced plastics(GFRP)m the mechanical properties of bulk at cryogenic temperatures have not been clarified. The purpose of this study is to reveal the mechanical properties of those ceramics and to investigate the improving mechanisms of mechanical properties at cryogenic temperature. | Mechanical Properties of Zirconia and Silica at Cryogenic Temperature | 10.1007/978-1-4757-9056-6_30 |
1998-01-01 | Cryogenic centrifugal compressors are presently the only «industrial» machines used to reach temperatures lower than 4.4 K (Tore Supra, Fermilab, TJNAL)^1,2,3. When the full cryogenic power is not needed, the processed flow is reduced. But the flexibility of a centrifugal compressor train is limited: reducing the processed flow rate leads to troubles (stall) and subsequently, surge. One of the easiest way to avoid such a situation is to inject electrical power into the liquid helium bath in order to provide the compressor train with a constant flow rate. This is not a very satisfactory procedure on a thermodynamical point of view... Other solutions have been proposed which generally lead to the operation of some parts of the room temperature helium circuits at sub atmospheric pressure, which is not consistant with a very long term reliable operation. Operating two parallel trains, each one processing half the nominal flow is another solution not very much flexible but which investment is roughly doubled. | Operating a Train of Cryogenic Centrifugal Compressors at Lower Flow Rates and Constant Compression Ratio | 10.1007/978-1-4757-9047-4_79 |
1998-01-01 | The United States Antarctic Program (USAP) has experienced an increase in the use of cryogenic fluids over the past decade. This increased use requires that the USAP purchase or lease suitable equipment, retain competent personnel, provide training to increase the knowledge base and find adequate storage for the inventory of equipment. Safety is extremely important to the USAP because of the remote location of the work. Antarctica remains as a lonely reminder that accidents do happen and that help may not be immediately available. Communication between remote stations often relies on radio or electronic mail. The geographic location adds long flight times to travel between these stations and the rest of the general population. Most of the safety aspects of the USAP are common to any other typical research program in a typical laboratory setting. The USAP also faces unexpected safety problems not generally encountered elsewhere. | Cryogenic Safety in the United States Antarctic Program | 10.1007/978-1-4757-9047-4_132 |
1998-01-01 | Three approaches to the production of compressed natural gas (CNG) for a 3500 Nm^3/day [1750 diesel equivalent gallon (DEG/day)] transit bus fleet were compared using a life cycle cost analysis approach. Three currently available methods of CNG production were compared. The analysis considered direct compression of pipeline natural gas and the compression and vaporization of liquefied natural gas (LNG) supplied by either tanker truck or locally produced with a small-scale liquefier. Considered contributions to the cost of CNG production included equipment capital costs, maintenance costs, operating costs, and feedstock price. CNG production with the use of a local liquefier resulted in the lowest total cost of fuel production. | A Comparative Study of CNG Production Methods for a 1750 DEG / Day Vehicle Fleet | 10.1007/978-1-4757-9047-4_150 |
1998-01-01 | The molecular structure of epoxy resins has been studied to improve the fracture toughness of epoxies at cryogenic temperatures. The mechanical and the thermal properties were investigated at cryogenic temperatures together with the molecular structure of epoxy resins. It was found that for the improvement of fracture toughness at cryogenic temperature, the thermal stress should be reduced that is reducing the thermal contraction was needed. To reduce the thermal contraction, the epoxy having high density and rigid molecular structure has been thought to be desirable. Such systems, however, were found to be brittle and the cracks were introduced during the cooling down process and sometimes even during the curing process. Consequently the another molecular design concept to improve the toughness of epoxy without decreasing dimensional stability is needed. The two-dimensional linear polymer of epoxy resin has been found to show superior properties at cryogenic temperature to the three-dimensional cross-linked epoxy resins. Referring the cryogenic properties of two dimensional epoxy resin the molecular design of epoxy resin for cryogenic use is discussed. | Toughening of Epoxy Resin Systems for Cryogenic Use | 10.1007/978-1-4757-9056-6_37 |
1998-01-01 | Molecular dynamics simulation of polymeric material was carried out in order to obtain the selection standard for the polymers having better characteristics at cryogenic temperatures. Several hundreds of spherical particles which modeled CH2 group were chained linearly and the equations of motion of each sphere was solved. The four types of forces originated from van der Waals, valence bond, valence angle and dihedral angle were considered. the effects of deformation and irradiation was studied. It will discussed that how the microscopic movement of molecules influence on macroscopic properties at cryogenic properties. | Molecular Dynamic Simulation of Polymeric Materials at Cryogenic Temperature | 10.1007/978-1-4757-9056-6_38 |
1998-01-01 | A simple and robust helium liqufier has been developed at CEA / SBT. It is a Collins type liquefier operated at atmospheric pressure in a standard commercial helium dewar. To increase reliability, the liquefaction circuit and the refrigerator are separated. Precooling and condensation temperature are provided by an hybrid closed cycle mechanical cryocooler: a commercial Gifford Mc Mahon cryocooler (Cryomech GB 37) is used as a precooler for helium gas to be liquefied and for the Joule Thomson expansion circuit (4.5 W at 4.5 K). The liquefaction circuit is designed to admit low purity helium. A prototype of this liquefier has been successfully operated for 6 months with a typical liquefaction rate of 1.1 liter per hour. | An Hybrid Cycle Helium Liquefier | 10.1007/978-1-4757-9047-4_216 |
1998-01-01 | To realize a 1GHz NMR magnet, superconductors with such features as high critical current, high n-value, high strength, enough weight of a continuous spool and so on are required. Two types of bronze-processed Nb_3Sn superconductors have been developed. One is the conductor for the inner coil with high critical current density (overall Jc) of over 100 A/mm^2 and n-value of over 20 at 21 T, 1.8 K, the other is the Ta reinforced conductor for the middle field coils with high yield strength of over 300 MPa at 4.2 K and the spool weight of more than 60 kg. Details of characteristics for these conductors are reported including overall Jc, n-value and mechanical properties. | Development of Bronze-Processed Nb_3Sn Superconductors for 1GHz NMR Magnets | 10.1007/978-1-4757-9056-6_123 |
1998-01-01 | General Atomics is designing, testing and fabricating a system for supplying cryogenic targets for the University of Rochester’s OMEGA laser system. A prototype system has demonstrated the filling of 1 mm diameter, 3 μm wall plastic spheres to 111 MPa (1100 atm) with deuterium and then cooling to 18 K to condense the fuel. The production design must be capable of routinely filling and cooling targets with a 50/50 mix of deuterium and tritium and transferring them to a device which places the targets into the focus of 60 laser beams. This paper discusses the design and analysis of the production Fill/ Transfer Station cryostat. The cryostat has two major components, a fixed base and a removable dome. The joint between the base and the dome is similar to a bayonet fitting and is sealed by a room temperature elastomeric o-ring. Since the cryostat must be housed in a glovebox, its design is driven strongly by maintenance requirements. To reach the equipment inside the cryostat, the dome is simply unbolted and lifted. The inside of the cryostat is maintained at 16 K by a closed loop helium flow system. Gaseous helium at about 1.4 MPa (200 psi) flows through tubes which are brazed to the inner walls. Cooling is provided by several cryocoolers which are located external to the cryostat. Liquid nitrogen is used as a heat intercept and to precool the helium gas. | Design of the Fill/Transfer Station Cryostat for the Omega Cryogenic Target System | 10.1007/978-1-4757-9047-4_73 |
1998-01-01 | The cryogenic system for the superconducting synchrotron Nuclotron consists of 3 – 1,600 W refrigerators operating at 4.5 K. Since the Nuclotron only requires the output of 2 of these refrigerators, a distribution system based on the “satellite” refrigerator concept was developed to maximize reliability of the overall refrigeration system while simultaneously maintaining a high level of system efficiency. This paper presents a thermodynamic analysis of, and the experimental data for, the Nuclotron refrigerators operating in the “satellite” mode. | Thermodynamic Analysis and Operating Experience of the Nuclotron Helium Refrigerators in the “Satellite” Mode | 10.1007/978-1-4757-9047-4_67 |
1998-01-01 | The largest installations for operation at liquid helium temperatures are presently being built in support of research in high energy physics or nuclear fusion. The associated refrigerators are normally being specified for peak refrigeration requirements. So they have spare capacity, which could be used for other investigations, e.g. for High Reynolds or Rayleigh Number research. Details are being presented of 7 systems, which are in operation or are in the planning stage in Europe. In the process of the design of these refrigerators, special machines had to be developed, which operate at low temperatures: high speed turbo expanders, liquid helium pumps and so called cold compressors. Some of the features of these machines could be used to develop circulation blowers for cryogenic wind tunnels. | European Large Scale Helium Refrigeration | 10.1007/978-1-4612-2230-9_3 |
1998-01-01 | This paper examines the results of long-life space cryocooler development and testing for various defense needs. For well over a decade, both the Air Force and the Strategic Defense Initiative Organization (now Ballistic Missile Defense Organization, or BMDO) recognized the need for long-life space cryocoolers capable of handling a variety of cooling loads spanning the temperature range between 8.5–150 Kelvin. Space borne cryocoolers had a multitude of defense system-level applications, including cryogenic cooling of chilled electronics/CMOS, infrared sensors, missile seeker precooling, launch platform systems checkout and health monitoring, maintaining stored cryogens, and high temperature superconducting device operation. Efforts to develop and fully demonstrate cryocoolers for long-term space operations have had mixed results, with several aspects of designs still preventing true long-life performance of these machines. This paper presents a summary of the results and conclusions of efforts to develop long-life cryocoolers. These results include findings from historical developments, current research areas, and Phillips Laboratory’s extensive ongoing cryocooler test and evaluation efforts. Information presented emphasizes key findings and lessons learned that may help improve existing designs and concepts so that these machines can finally realize their long-life potential. These lessons learned are also examined in light of newly emerging space system requirements that will set the pace for long-life, high efficiency, larger capacity cryocoolers well into the next decade and beyond. | Phillips Laboratory Space Cryocooler Development and Test Program | 10.1007/978-1-4757-9047-4_207 |
1998-01-01 | A cryogenic thermometer calibration facility has been designed and is being commissioned in preparation for the very stringent requirements on the temperature control of the LHC superconducting magnets. The temperature is traceable in the 1.5 to 30 K range to standards maintained in a national metrological laboratory by using a set of Rhodium-Iron temperature sensors of metrological quality. The calibration facility is designed for calibrating simultaneously 60 industrial cryogenic thermometers in the 1.5 K to 300 K temperature range, a thermometer being a device that includes both a temperature sensor and the wires heat-intercept. The thermometers can be calibrated in good and degraded vacuum or immersed in the surrounding fluid and at different Joule self-heating conditions that match those imposed by signal conditioners used in large cryogenic machinery. The calibration facility can be operated in an automatic mode and all the control and safety routines are handled by a Programmable Logic Controller (PLC). Lab VIEW® is used both as the PLC operator interface and for configuring and reading the thermometric data sampled by the higher accuracy laboratory equipment. The isothermal support onto which the thermometers are mounted is thermally anchored through the wiring to a helium bath. The calibration procedure begins once the temperature of the support is stabilized. Measured data is presented and it is possible to infer that the absolute accuracy that can be obtained is better than ± 5 mK for the full temperature range. | Cryogenic Thermometer Calibration Facility at CERN | 10.1007/978-1-4757-9047-4_92 |
1998-01-01 | Optical Dynamic RAM (ODRAM) is the first entry in an entirely new class of memory devices, offering price and performance levels that are unachievable with any other technology. ODRAM will have the capacity of magnetic hard drives but will allow up to a three order of magnitude improvement in access time. ODRAM will pro vide this performance advantage at a fraction of the cost of Silicon RAM. The extraordinary performance levels offered by ODRAM, which are the direct result of operation at cryogenic temperatures, will easily justify the expense of cryogenic operation. ODRAM offers a new and unique opportunity for cryogenic technology to address large markets and become an important technology in future Computing and communications applications. | Cryogenically Cooled Optical Dynamic RAM | 10.1007/978-1-4757-9047-4_107 |
1998-01-01 | While liquid helium is an ideal fluid for obtaining precise thermal information on mean convective flow in Rayleigh-Bénard geometry, flow pattern details have until now only been measurable with room temperature fluids. We show that it is now possible to visualise convective flow patterns in a cylindrical sample of liquid helium of vertical height 0.7mm and diameter 20mm using a shadowgraph system completely contained within the cryogenic environment of a cryostat. Flow pattern images are presented under various heating conditions. | First images of controlled convection in liquid helium | 10.1007/978-1-4612-2230-9_33 |
1998-01-01 | For the international thermonuclear reactor (ITER), we developed a novel system for electrical insulation of the conductor turns. It consists of a tetrafunctional epoxy with an aromatic-amine cure preimpregnated in a satin-weave S-2 glass that is cowound with Kapton film. This preimpregnated system is fabricated into tape that is wound onto the conductor of each central-solenoid coil layer, cured, and inspected—an on-line process. Extensive testing has demonstrated that this system is very radiation resistant. We measured the shear, shear/compression, compression, fatigue, thermal contraction, and dielectric strength properties at 77 and 4 K; at 77 K, we conducted large-scale compression-fatigue tests with intermittent turn-to-turn voltage-breakdown measurements of conductor arrays. | Development of U.S./ITER CS Model Coil Turn Insulation | 10.1007/978-1-4757-9056-6_23 |
1998-01-01 | Three different conventional gas cooled power leads have been developed at Brookhaven National Laboratory for use in the Relativistic Heavy Ion Collider (RHIC). The RHIC cryogenic system will contain over 500 leads, which will be responsible for as much as 24% of the total 4.5 K refrigerator heat load. Leads optimized for 6300 A and for 1600 A are constructed with variable heat transfer segments and conductor cross sections so as to operate frost free over a wide range of currents without compromising safety or efficiency. A second type, which consists of a 12 lead bundle each carrying 150 A, is an improvement of an existing design, where parallel conductors are pressed into the perimeter of a plastic core. Each type of lead was optimized for minimum refrigeration load while maintaining a margin of safety in the event of coolant flow loss. The 6300 A and 1600 A leads will operate at 0.06 g/s-kA up to and including their design currents, and the 12x150 Amp lead bundle was stable at 0.09 g/s-kA. A mathematical model of each type of lead, which includes warm end components connecting it to the power supply and cold end superconductor, has been developed. The design and test result for each type of lead is presented here, and comparisons are made to their theoretically predicted performance. | Performance of Magnet Leads for RHIC | 10.1007/978-1-4757-9047-4_30 |
1998-01-01 | A Linde-Hampson device has been developed, which incorporates the effects of positive and negative Joule-Thomson coefficients. Successive streams of pressurized gases, under and above their inversion temperatures (like nitrogen, argon, nitrous oxide on the one hand and neon or helium on the other), result in sequential cooling and heating. Fast cryocycling is obtained, because of the very low thermal inertia involved in a miniature Joule-Thomson “cooler”. Consequently, a fast freeze and thaw complete cycle between 325 K and 105 K was accomplished within 20 s utilizing a 5.2 mm diameter surface heat loaded probe. A computer regulated fast electromagnetic valve and a thermocouple feedback have been used to maintain any steady state intermediate temperature and control temperature extremes and periods of cooling and warmup. The fast cycling capability provides a new dimension in the domain of cryo-interaction with living tissues. In this way the cryodestructive process of undesirable cells is intensified. Cold front depth of penetration may be controlled and calibrated in an open loop through frequency dependence. This may be extremely significant for delicate surgeries like those in the eye and brain. In addition, it enables frequency dependent selective cryodestruction. | Fast Joule-Thomson Cryocycling Device for Cryosurgical Applications | 10.1007/978-1-4757-9047-4_114 |
1998-01-01 | A single stage double inlet pulse tube refrigerator has been operated with two different types of regenerators, a conventional one, made from 200 mesh stainless steel screens, and a new type made from a stack of Chapaullel channels arranged in 0.1 mm thick stainless steel foils. The overall dimensions of both are the same, but the Chapaullel flow system has only half the void fraction as the mesh type. The initial expectation to get better performance of the cooler with the Chapaullel flow regenerator has not been fulfilled. The no-load temperature of the mesh type system is 26 K, whereas only 33 K could be achieved with the Chapaullel flow regenerator. A more detailed analysis based on data of Kays and London and on numeric studies based on the thermoacoustic theory is given. | Parallel Flow Regenerator for Pulse Tube Cooler Application | 10.1007/978-1-4757-9047-4_204 |
1998-01-01 | Previous superfluid Stirling refrigerators (SSR) using CuNi recuperators have experimentally achieved temperatures of 0.168 K and 0.296 K operating from high temperatures of 0.383 K and 1.05 K respectively. This article describes the theoretical performance of a single stage SSR and a two stage SSR which use Kapton recuperators. Specifically, a single stage SSR operating from a high temperature of 1.0 K should achieve a low temperature of 0.22 K and deliver 420 µW of cooling power at 0.3 K. A two stage SSR operating from a high temperature of 1.0 K should reach a low temperature of 0.12 K and deliver 750 µW of cooling power at 0.30 K. | Theoretical Performance of Single Stage and Two Stage Superfluid Stirling Refrigerators Using Kapton Recuperators | 10.1007/978-1-4757-9047-4_236 |
1998-01-01 | We present our new astronomical wide field imager, which consists of two 4k x 8k CCD mosaic cameras allowing simultaneous imaging in two focal planes with different color passbands. Each mosaic is maintained at 180K by using a fully automated original cryogenic system without LN2. A modular electronic system permits an individual computer controlled setting and a parallel readout of the CCDs. An acquisition system has been developed in order to process the data rate of 10–15 Gbyte per night. The described instrumentation will be used in a sky-survey and sky-patrol to search for gravitational microlenses, supernovae and red dwarfs | The Two EROS 4k x 8k CCD Mosaic Cameras | 10.1007/978-94-011-5262-4_29 |
1998-01-01 | Cryosurgery is the destruction of tissue by freezing. Modern cryosurgical techniques were first introduced in the mid 1960’s, but, they only achieved modest application in selected medical specialties. This was in part due to limitations in cryosurgical devices which could not address the fundamental factors that influence cell death in response to freezing. It was also due to an inability to accurately assess or predict the growth of the ice ball within the tissue, and more importantly determine the zone of tissue death. Recent advances in liquid nitrogen cryosurgical devices and ultrasound guided cryosurgical techniques have addressed some of these issues, have significantly raised the interest in cryosurgery, and have expanded its application. Newer advances in cryosurgical devices and magnetic resonance imaging have great promise in making cryosurgery a primary therapeutic modality. This paper will review the biologic issues related to the freezing of tissue and their impact on the development of cryosurgical devices, as well as discuss the newest developments at the forefront of cryosurgical applications. | A Review of Cryobiology and Cryosurgery | 10.1007/978-1-4757-9047-4_111 |
1998-01-01 | A two-stage 4 K Modified-Solvay cycle cryocooler^1, which is a pneumatically driven Gifford — McMahon cryocooler and will be used for the conduction-cooled low temperature superconducting magnets, has been optimized by numerical and experimental study. After the optimization, the maximum cooling capacity of 36.5 W at 35 K on the first stage and 1.08 W at 4.2 K on the second stage with 6.7 kW input power has been obtained. This is the world’s first pneumatically driven G-M cryocooler which has over 1 W cooling capacity at 4.2 K. In this paper, experimental and numerical results of the influence of the valve opening timing and the displacer motion concerning the cooling capacity are described. The experimentally obtained optimum P-V diagram and valve timing are in good agreement with the numerical simulation results. And the reliability tests (over 100 times of cool-down and warm-up cycle, and over 3,000 hours continuous operation) were successfully conducted. It can be expected that this 4 K cryocooler has a high reliability equivalent to the commercial G-M cryocoolers which operate above 10 K on the 2nd stage temperature. | Numerical and Experimental Study of a 4 K Modified-Solvay Cycle Cryocooler | 10.1007/978-1-4757-9047-4_226 |
1998-01-01 | A phenomenon of gas separation owing to diffusion through polymeric films or membranes is known since last century, however it found practical application only as late in 1980s. At present it is considered as a prospective approach and as an alternative to such well-established methods of separation, as cryogenic distillation, adsorption, and absorption. In a vast majority of cases commercial polymers produced on large scale, and not specifically synthesised polymers with unique properties were used as membrane materials. Now it is clear that future progress in this field will demand a concerted efforts of synthetic chemists and physico-chemists aimed at the elaboration of specialty polymers and membrane materials of the next generation. | Synthesis of Membrane Materials by Romp of Norbornenes | 10.1007/978-94-011-5188-7_11 |
1998-01-01 | Installation and testing of the first sextant of RHIC magnets has been completed. The tests consisted of temperature cycling, quenching magnets, and measuring important engineering parameters of a string of magnets totaling a length of over 500 meters. This represents one sixth of the 3.8 kilometer circumference of the RHIC machine and serves as a basis for extrapolation of parameters for full machine operation. This paper gives an overview of the entire system, a detailed discussion of startup problems, operations and cryogenic system reliability over the period of the test and details of some of the important cryogenic operating parameters. | Performance and Operating Experience of the RHIC First Sextant Test | 10.1007/978-1-4757-9047-4_27 |
1998-01-01 | A superconducting magnetic energy storage (SMES) system for utility applications is planned for installation at Anchorage Municipal Light & Power in 2000. The system’s stored energy of 1800 MJ (0.5 MWh) will be delivered at power levels up to 31.5 MVA for spinning reserve, voltage support and electrical network stabilization. A low aspect ratio solenoidal superconducting magnet will store and deliver energy. The magnet’s maximum operating current is 10.8 kA and the peak field in the winding is 6.1 T. The maximum discharge voltage is 3.375 kV. The magnet will be cooled by pool boiling helium at 4.45 K. A review of our conductor configuration trade analysis and a description of the cryostable, copper stabilized, NbTi conductor is presented. Conductor characteristics including stability are discussed. The pancake winding pack is described. Magnet quench characteristics and protection are presented. Current lead selection criteria are presented and the leads are described. Cryostat design is described and overall magnet system thermal and structural characteristics are presented. Seismic conditions in the Anchorage area are identified and associated structural issues discussed. Thermal loads are discussed and a description of the refrigeration system is provided. Implications due to the unavailability of LN_2 are discussed as well as the required recovery of the cryogenic system from discharge events. | Alaska SMES: Form and Function for the World’s Largest Magnet | 10.1007/978-1-4757-9047-4_133 |
1998-01-01 | An Ic-B-T characteristic (critical current vs. magnetic field at various temperatures) for multifilamentary NbTi superconducting (SC) wire has been measured by using a conduction cooled critical current measurement apparatus up to 300A and up to 5T, in the temperature range from 5K to 7.5K. Two types of cryogen-free (C-F) SC magnets, a large bore type and a high field type, have been designed and fabricated based on these Ic-B-T characteristics for the multifilamentary NbTi SC wire. The large bore type and the high field type magnets generated 5T and 10T stable magnetic field at the center of the room temperature bore of 300mm and 100mm diameter, respectively. The average heat generation while energizing is obtained based on the temperature dependence of the cryocooler’s cooling capacity. This average heat generation agrees well with the hysteresis loss of the whole magnet, calculated based on the hysteresis data for the multifilamentary NbTi short sample. | Development of Two Types of Cryogen Free Superconducting Magnets (5T-ϕ300min and 10T-ϕ100mm) | 10.1007/978-1-4757-9047-4_35 |
1998-01-01 | The installation and testing of most of the Relativistic Heavy Ion Collider (RHIC) cryogenic system is complete. The RHIC cryogenic system consisting of the modified ISABELLE refrigerator, and other new cryogenic components, has been completed from the 25 kW refrigerator through one sixth of the 3.8 km circumference RHIC accelerator up to the 4:00 valve box. This paper covers the progress to date with respect to construction and installation of the helium distribution system, including the vacuum jacketed piping and valve boxes, recoolers, and controls. In addition, the 25 kW refrigerator has been operated on three seChapaute occasions over the past two years. These first experiences with the operation of the refrigerator and warm compressor system, along with some test results will be discussed here. | RHIC 25 kW Refrigerator and Distribution System, Construction, Testing, and Initial Operating Experience | 10.1007/978-1-4757-9047-4_60 |
1998-01-01 | There is an increasing requirement for the use of composite materials in applications at cryogenic temperatures, especially in spacecraft and liquid propellant propulsion systems. This paper reports on a simple technique for measuring the in-plane thermal conductivity of composite laminate materials between 4K- 300K. The measurement apparatus is constructed entirely within a 5cm diameter, 1.5m long evacuated stainless steel tube. The probe-like device is designed to be immersed in liquid helium contained in a standard transfer dewar. The thermal conductivity of various composite laminates was obtained at temperatures between 5K and 300K. The apparatus was calibrated using a NIST austenitic stainless steel standard reference material (1462). The results suggest that this novel approach is suitable for practical thermal conductivity measurements at cryogenic temperatures, while minimizing the usage of liquid helium. | Simple Guarded Hot Plate Technique for Making Thermal Conductivity Measurements of Composite Materials at Cryogenic Temperatures | 10.1007/978-1-4757-9056-6_46 |
1998-01-01 | Fermilab successfully installed and used off-the-shelf industrial controllers and software to operate five 600 Watt, one 90 Watt liquid helium refrigerators, seven strings of superconducting magnets and three liquid hydrogen targets and other miscellaneous Subsystems. The equipment is distributed over a 3 km by 3 km area. The planning, wiring installation and programming was done entirely by mechanical engineers and technicians familiar with the processes being controlled, and in conjunction with their usual jobs. No computer programmers were involved. Sophisticated control schemes such as cascade PID, adaptive gains and automated quench recovery were employed on the Moore Products APACS and Siemens/TI controllers. Intellution FIX DMACS software running on PCs (with a Windows platform) provides alarming, data logging and interactive customized graphical displays of the processes for operators, engineers and managers. From any of 20 FIX DMACS nodes operators can change set points or other parameters on any of the Subsystems. The FIX DMACS nodes communicate to each other over Ethernet using TCP/IP protocol and potentially can read/write to any other parameter in the controllers. Operational problems, operator man-hours and off hour call-ins have been dramatically reduced. | Application of Industrial Control Systems to a Large Scale Cryogenic System | 10.1007/978-1-4757-9047-4_105 |
1998-01-01 | Until recently, the problem of low test Reynolds number has limited the usefulness of wind tunnels, especially at transonic speeds. For general-purpose testing, we achieve the best solution to the problem of low test Reynolds number when we operate a relatively big tunnel (2 × 2 m test section or larger) at a relatively high pressure (up to 3 or 4 bar) at cryogenic temperatures using nitrogen (or nitrogen-rich air) as the test gas. The first cryogenic wind tunnel was a low-speed tunnel built at the NASA Langley Research Center in 1972. Since then, workers at research centers around the world have started a large number of cryogenic wind-tunnel projects. The degree of success of the various projects depends on many things. The more successful cryogenic tunnels reflect a skillful combination of cryogenic technology with wind-tunnel technology. In this paper, I review the principles of operation and the history of cryogenic wind tunnels. I list in a table the main operating characteristics of the 20 cryogenic tunnels presently operational in 9 countries. I also describe some of the larger cryogenic tunnels presently being used for aerodynamic research. | Cryogenic Wind Tunnels for Aerodynamic Testing | 10.1007/978-1-4612-2230-9_4 |
1998-01-01 | The NICMOS dewar design was driven by requirements for long cryogen lifetime and minimal detector contamination. Several unique design features were implemented to meet the long-lifetime requirement, and are discussed. These include thermoelectric cooling, a single cryogen fill/vent line, and unique electrical cabling. Because the dewar annulus vacuum is not opened to space after launch, component outgassing was carefully evaluated during dewar integration. A series of tests was performed to evaluate the contributions of all non-metallic materials. Development of the outgassing rate specification and comparison to the measured rate at the end of dewar vacuum acquisition is presented. The methods used for long-term vacuum maintenance following pumpout, and long-term performance results are presented. The no-vent LN_2 fill technique and the fill efficiency achieved using this process are described. | Development of the Long-Lifetime Solid Nitrogen Dewar for NICMOS | 10.1007/978-1-4757-9047-4_116 |
1998-01-01 | The Large Hadron Collider (LHC), currently under construction at CERN, will make use of superconducting magnets operating in superfluid helium below 2 K. The reference cryogenic distribution scheme was based, in each 3.3 km sector served by a cryogenic plant, on a separate cryogenic distribution line which feeds elementary cooling loops corresponding to the length of a half-cell (53 m). In order to decrease the number of active components, cryogenic modules and jumper connections between distribution line and magnet strings a simplified cryogenic scheme is now implemented, based on cooling loops corresponding to the length of a full-cell (107 m) and compatible with the LHC requirements. Performance and redundancy limitations are discussed with respect to the previous scheme and balanced against potential cost savings. | A Simplified Cryogenic Distribution Scheme for the Large Hadron Collider | 10.1007/978-1-4757-9047-4_47 |
1998-01-01 | The construction and the cooling schemes of the cryogenic system for the Large Helical Device (LHD) are reported. The LHD is the first fully superconducting heliotron type experimental fusion device, which is under construction at the National Institute for Fusion Science (NIFS). The cryogenic system for the LHD consists of the helium refrigerator, the superconducting helical and poloidal coils and the peripheral equipment, such as superconducting bus-lines, control-valve-boxes and cryogenic transfer-lines. Three different cooling schemes are utilized for each cooling object; a pool boiling for the helical coils, a forced flow supercritical helium for the poloidal coils, a forced flow two phase helium for the coil supporting structure and the superconducting bus-lines. Many technical know-how were applied to develop the complicated cryogenic system for the LHD, which we could gather during the engineering research and developments such as the single coil test of the IV poloidal coil, the development and tests of the full-scale model of superconducting bus-lines and the test operation of the helium refrigerator with a dummy load apparatus. | Development of a Cryogenic System for the Large Helical Device | 10.1007/978-1-4757-9047-4_71 |
1998-01-01 | The LHC interaction region (IR) inner triplet cryostats are under development at Fermilab. The inner triplet consists of four 70 mm aperture superconducting quadrupole magnets manufactured at Fermilab and KEK. These magnets are cooled with pressurized static superfluid helium at 1.9 K which transports the heat to saturated 1.8 K He II via a He II heat exchanger. This paper discusses the requirements for the inner triplet cryostat, development of the cryogenic system, and He II heat exchanger arrangement. Cooldown and quench pressure issues with the external He II heat exchanger are also discussed. | Cryogenic System and Cryostat Design for the LHC IR Quadrupole Magnets | 10.1007/978-1-4757-9047-4_48 |
1998-01-01 | A cryogenic system has been operational in TJNAF’s Hall C for four years. The design of this system is presented and the operational and control philosophy is discussed. The system consists of conventional rigid transfer lines and a unique flexible transfer line. The features and heat load measurements of this flexible line are presented. Operational data are stored continously on computer disc. There are typical plots of this data presented to illustrate system stability. The cryosystem for Hall C is used to operate the superconducting magnets of the HMS spectrometer and a cryogenic target for H2, D2 and He. | Cryogenic System for TJNAF’s Hall C | 10.1007/978-1-4757-9047-4_72 |
1998-01-01 | Within the framework of the European Fusion Technology Programme, a cryopump system for ITER is being developed. The pumping characteristics of cryosorption panels coated with activated carbon are investigated under ITER relevant operating conditions. The underlying design of the panels described in this paper is generally accepted for the cryopump system of the ITER tokamak. Quantitative vacuum pumping performance data are obtained by the measurement of pumping speed as a function of gas load and pumping pressure for various gases. We have investigated pure gas species (helium, protium and deuterium) and their mixtures. Our measurements have been performed to determine the major factors affecting cryopumping performance, such as flow rate, charcoal saturation, panel temperature and pressure during pumping. Selectivity of mixture pumping has been monitored by the use of a gas mass spectrometer. Dynamic loading effects due to the mobility of the molecules are also investigated. The results presented demonstrate the flexibility and assess the constraints of the recommended pump concept. | Pumping Performance of Cryopanels Coated with Activated Carbon | 10.1007/978-1-4757-9047-4_166 |
1997-12-01 | The microstructure of a fine grained 16.5 mol% CeO2-stabilized tetragonal zirconia polycrystal (Ce-TZP) has been investigated by transmission electron microscopy observations. The results show that the samples fractured at 298, 77 and 4.2 K change significantly. At 298 K, there is no stress-induced martensite but a few anti-phase boundaries (APB) in the tetragonal (t) parent phase. With a decrease in testing temperature, monoclinic (m) product, or martensite within retained t phase, appears. Its morphologies are characterized as lenticular and block-like at 77 K and as lenticular and butterfly-like at 4.2 K. The relationship between microstructure and mechanical properties is also discussed. | Microstructure of a sintered 16.5 mol% CeO2-ZrO2 alloy at cryogenic temperature | 10.1023/A:1018626219676 |
1997-12-01 | Centrally released arginine vasopressin (AVP) has been implicated in the regulation of the brain water content and is elevated in the cerebrospinal fluid of patients with ischaemic and traumatic brain injuries. The protective effect of RU51599, which is a selective kappa opioid agonist as an AVP release inhibitor, on brain oedema was examined. Male Wistar rats, weighing 300 to 400 g each, were used. The cortical cryogenic injury was produced by application of a previously prepared metal probe cooled with dry ice to the dura of the right patietal region. Animals were separated into three groups. Group 1: sham operated rats without lesion production. Group 2: saline-treated rats with lesion production. Group 3: RU51599-treated rats with lesion production. In Group 3, rats were treated with RU51599 (0.1–3 mg/kg) at 30 minutes before lesion production, 1 hour, 2 hours, and 4 hours after lesion production. After 6 hours, animals were decapitated and brain water contents were measured using the dry-wet weight method. The extent of blood brain barrier (BBB) disruption was determined by assessment of Evans blue uptake based on extraction from tissue using dimethylformamide. The primary injured infarcted area was determined by 2,3,5-triphenyltetrazolium chloride (TTC) staining. Sodium and potassium contents in serum and brain tissue were measured using atomic absorption spectrophotometry. The antagonism of naloxone against protective effects of RU51599 on cryogenic induced brain oedema and on antinociceptive effects in acetic-acid treated animals was examined. Statistical analysis was performed using Dunnett-test and U-test following Kruskal-Wallis test. RU 51599 significantly reduced the brain water contents on the injured side and the contralateral non-injured side (p<0.01) after 4 administration of 1 and 3 mg/kg. RU51599 neither significantly inhibited BBB disruption nor reduced the primary injured infarcted area. RU51559 significantly increased brain sodium and potassium contents in the injured brain and also increased serum sodium levels (p<0.01). Naloxone antagonized the anti-oedema effects and antinociceptive effects of RU51599. These findings indicate that the AVP release inhibitor, RU51599 posssibly mediated by opioid receptors, has a potential protective effect on cryogenic-induced brain oedema and that centrally released AVP plays an important role in the progression of vasogenic brain oedema. | Attenuation of cryogenic induced brain oedema by arginine vasopressin release inhibitor RU51599 | 10.1007/BF01410979 |
1997-11-01 | We analyze the behavior of metallic barlike structural elements with triangular and trapezoidal cross sections reinforced with unidirectional epoxy boron plastic and subjected to tension and compression under conditions of liquid nitrogen and at room temperature. We describe methods for evaluation of the load-carrying capacity of structures of this sort with account for the strength of the components and the mechanical bonds between them and give recommendations on the proper choice of geometric parameters of the shape of reinforced bars. | Load-carrying capacity of barlike elements reinforced with boron plastic | 10.1007/BF02767610 |
1997-09-01 | A developed physicomathematiccd model of pipeline cooling by a liquid cryoagent is presented; some results of mathematical simulation of the process are given; the results are compared with experimental data to determine the adequacy of the description of real physical processes by the model. | Hydrodynamics of pipeline filling with cryogenic fluid | 10.1007/BF02657626 |
1997-08-01 | Cryogenic thermoelectric coolers have been fabricated from an active element (polycrystalline Bi_0.88Sb_0.12) and three different passive elements, a high-T_c superconductor (polycrystalline YBa_2Cu_3O_7-δ), and lengths of high purity copper and aluminum wires. The results for a single couple show that for low, hot junction (sink) temperatures the superconducting element gives rise to maximum temperature drops of 6.6 degrees K at 70K and 7.3 degrees K at 75K in applied magnetic fields of 0.0 and 0.07 T, respectively. Temperature drops of∼9 and 11K, respectively, are expected for such a couple when form factors are taken into account. The copper couple with an applied magnetic field resulted in large cooling δT values at T_hot = 150 and 293K, indicating the importance of metallic passive elements for intermediate sink temperatures. Performance curves for the superconductor based cryogenic thermoelectric cooler show promise with further improvement possible by the use of single crystalline Bi_0.85Sb_0.15. | Cryogenic thermoelectric cooler with a passive branch | 10.1007/s11664-997-0274-6 |
1997-07-01 | Multilevel system for planning cryogenic equipment operating under transitional conditions | 10.1007/BF02416730 | |
1997-05-01 | On the basis of the proposed method of additional pulse loading of static preloaded specimens at temperatures of 293 and 77 K, we theoretically and experimentally established the possibility of effects similar to the effects of low-temperature discontinuous yield. The obtained effects are caused by operating-technological factors and can be observed only in the process of deep cooling. In particular, by using 03Kh20N16AG6 steel as an example, we show that as the loading rate, the level of preliminarily inclused strains in the material, or the amount of accumulated elastic energy of the loaded system increase, the jumplike development of strains results in a sharp decrease in strain resistance. | Simulation of low-temperature discontinuous yield by the method of additional pulse loading | 10.1007/BF02767444 |
1997-04-01 | Authors’ reply | 10.1007/s11661-997-0238-8 | |
1997-04-01 | Hotspot | 10.1007/s11665-997-0003-6 |
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