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1990-01-01 | This paper discusses the design and construction of an apparatus to measure the ineffectiveness of regenerators used for pulse tube refrigerators. Because of the fairly large mass flow rates which occur in pulse tube refrigerators, the regenerator ineffectiveness must be made quite small. The apparatus described here allows for the measurement of the regenerator’s heat loss under actual operating conditions in a pulse tube refrigerator. A low temperature heat sink of liquid nitrogen is used since it approximates the temperatures normally achieved in a one-stage pulse tube. | An Apparatus for the Measurement of Regenerator Performance in Pulse Tube Refrigerators | 10.1007/978-1-4613-0639-9_145 |
1990-01-01 | The present paper describes briefly the apparatus and the testing methods to define optimal conditions for the use of strain gages at cryogenic temperatures. The power dissipated per unit area may induce serious errors in interpreting results if suitable corrections are not made. The paper gives results on the apparent strain due to self-heating and on thermal drift over several ranges of dissipated power, both with continuous and pulse supply. A linearization of the apparent strain vs. temperature curve near liquid helium temperature was demonstrated possible by changing the operating temperature of the strain gage grid and by applying a pulse supply technique. | Strain Analysis at Cryogenic Temperatures: Self-Heating Effect and Linearization of the Apparent-Strain Curve | 10.1007/978-1-4613-0639-9_190 |
1990-01-01 | This chapter describes and illustrates the major types of containers used to transport and store compressed and liquefied gases, including those liquefied at very low or cryogenic temperatures. To keep pace with developments in the industry, the Compressed Gas Association, 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. This chapter provides an overview of the following types of compressed gas containers and their associated appurtenances: Cylinders and small containers Regulators and control valves for cylinders and other containers Containers for shipping by rail in bulk Cargo tanks and tube trailers Portable tanks and ISO containers Containers for shipping by water in bulk Cryogenic containers Stationary storage containers Pipelines | Compressed Gas Containers and Appurtenances | 10.1007/978-1-4613-0673-3_4 |
1990-01-01 | This chapter introduces the substances designated as compressed and liquefied gases in descriptive terms, and mentions some uses and other general considerations which may provide useful background information, especially to anyone unfamiliar with the field. Included are descriptions of the various groupings and families into which gases may be categorized, as well as information concerning standard units of measurement. | Compressed and Liquefied Gases Today | 10.1007/978-1-4613-0673-3_1 |
1990-01-01 | He II has played and will continue to play a significant role in space, both as a cryogen and as a subject of experiment in its own right. Major applications include the completed Infrared Astronomical Satellite and the Spacelab 2 Infrared Telescope missions. Planned missions include the NASA Cosmic Background Experiment, the Space IR Telescope and the Large Deployable Reflector as well as the European Space Agencies’ Infrared Space Observatory. Science experiments include the completed Superfluid Helium in Zero Gravity Experiment and the planned Superfluid Helium On- Orbit Transfer and Lambda Point experiments. In all of these missions, the unique properties of He II play an essential role. This paper describes past and future applications and experiments on helium II in the space environment. | Science and Applications of HE-II in Space | 10.1007/978-1-4613-0639-9_9 |
1990-01-01 | Fermilabs superconducting accelerator, the Tevatron has been operational for over six years. The Tevatron is a proton/antiproton collider used in high energy physics research. The cryogenic system is a hybrid design, consisting of a 4000 liter/hour central helium liquefier and twenty four 1 kw satellite refrigerators. Operating experience of the cryogenic system is discussed, including a historical perspective, accelerator systems downtime comparison, and specific hardware experiences. Upgrade plans for the cryogenic systems includes improvements in reliability and in accelerator performance. To improve long term reliability, a second central helium liquefier with a 35% higher capacity is being constructed for operation in 1990. Plans to increase the operating energy of the accelerator to 1 TeV include the use of twenty four cold vapor compressors to lower the operating temperature of the magnets. | Current Operating Experience and Upgrade Plans of the Tevatron Cryogenic System | 10.1007/978-1-4613-0639-9_110 |
1990-01-01 | Thermal performance measurements of a 100 percent polyester multilayer insulation (MLI) system for the Superconducting Super Collider (SSC) were conducted in a Heat Leak Test Facility (HLTF) under three experimental test arrangements. Each experiment measured the thermal performance of a 32- layer MLI blanket instrumented with twenty foil sensors to measure interstitial layer temperatures. Heat leak values and sensor temperatures were monitored during transient and steady state conditions under both design and degraded insulating vacuums. Heat leak values were measured using a heatmeter. MLI interstitial layer temperatures were measured using Cryogenic Linear Temperature Sensors (CLTS). Platinum resistors monitored system temperatures. High vacuum was measured using ion gauges; degraded vacuum employed thermocouple gauges. A four-wire system monitored instrumentation sensors and calibration heaters. An on-line computerized data acquisition system recorded and processed data. This paper reports on the instrumentation and experimental preparation used in carrying out these measurements. In complement with this paper is an associate paper bearing the same title head, but with the title extension PART II: LABORATORY RESULTS (300K-80K).^1 | Thermal Performance Measurements of a 100 Percent Polyester MLI System for the Superconducting Super Collider; Part I: Instrumentation and Experimental Preparation (300K - 80K) | 10.1007/978-1-4613-0639-9_58 |
1990-01-01 | Recent advances in sorption refrigeration have resulted in concept designs which offer greatly improved performance. The predicted input power required to drive a four-stage cryocooler producing 1 W of cooling at 25 K is reduced from 1160 W for a conventional sorption refrigerator to 195 W for an advanced concept sorption refrigerator. An analytical model has been developed to predict the advanced concept cooler input power. The algorithm that sizes the refrigerator and predicts cold end performance parameters was verified during performance tests of a 26 K hydride cooler. A second routine, which predicts the energy required to thermally cycle the compressor, was verified with a simulated advanced concept sorption cooler built in 1988. This routine accurately predicted regenerative the efficiency of the simulated system to within 3 percent of the 75.9 percent results that were achieved. This paper presents the concepts which describe the advanced design, the analytical model used to predict performance and the experiments conducted to validate this model. The design and component test results of a 4 W, 130 K regenerative sorption refrigerator currently under development are presented elsewhere.^1 | High Efficiency Sorption Refrigerator Design | 10.1007/978-1-4613-0639-9_163 |
1990-01-01 | A test apparatus has been developed for studying the ineffectiveness of thermal regenerators as an essential part of the present new regenerator materials research and development program. Magnetic materials Er_3Ni and Er_0.5Dy_0.5Ni_2 are used as regenerator materials to make a comparison with lead between 4 and 35 K. In the apparatus, the helium gas flow through test regenerators can be switched to an alternate cold (or hot) flow in step-function fashion. The flow rate has been changed from 0.98 to 2.46 g/s and the switching time of the flow has been changed from 1 to 5 s. The details of the apparatus are described in the present paper. The ineffectiveness measurements show that the regenerator efficiencies are considerably high for Er_3Ni and Er_0.5Dy_0.5Ni_2 and the magnetic materials are more suitable for regenerator materials than lead below 15 K. | Measurement of Ineffectiveness on Regenerators Packed with Magnetic Regenerator Materials Between 4 and 35 K | 10.1007/978-1-4613-0639-9_142 |
1990-01-01 | NASA’s Lewis Research Center (LeRC) is involved in the development and validation of analytical models which describe the fluid dynamic and thermodynamic processes associated with the storage, acquisition and transfer of subcritical cryogenic fluids in low-gravity. These technologies are considered enabling for future NASA space missions. Four concurren studies, including one in-house at LeRC, are underway to determine the feasibility of performing model validation experiments aboard a free-flying spacecraft (S/C) called Cryogenic On-Orbit Liquid Depot — Storage, Acquisition and Transfer (COLD-SAT), using liquid hydrogen as the cryogen. This paper describes the technology requirements for the experiments, and presents the initial LeRC concepts for the S/C and an experiment subsystem comprising of cryogenic tankage (a supply dewar and three receiver tanks), gas pressurization bottles (both helium and autogenous hydrogen), their associated plumbing, and instrumentation for data collection. Experiments have been categorized into enabling/high priority Class I technologies and component/system Class II demonstrations. As initially envisioned by LeRC, COLD-SAT would have had a 1997 launch aboard a Delta-II for a six month active lifetime in a 925 km orbit with a pseudo-inertial attitude. | Cold-Sat: A Technology Satellite for Cryogenic Experimentation | 10.1007/978-1-4613-0639-9_199 |
1990-01-01 | Cryopreservation is the process by which viable tissues are stored at ultra-low temperatures (-196°C) in liquid nitrogen. Metabolism is suspended and evidence suggests that genetic stability is maintained. The following provides a brief account of cryopreservation methodology (see also Withers, 1987; Benson and Withers, 1988). | The Control by Cryopreservation of Age-Related Changes in Plant Tissue Cultures | 10.1007/978-1-4684-5760-5_15 |
1990-01-01 | The speed, reliability and, noise characteristics of most semiconductor devices improve with cooling to cryogenic temperatures. In addition, certain unique capabilities become available at these temperatures through the use of superconducting electronics. We discuss progress in the development of the technology for the selective or “spot cooling” of devices and individual chips using microminiature Joule-Thomson refrigerators for the lower temperature range. Likewise we discuss the recent development of circuit board coolers for higher temperature applications for the cooling of CMOS, PALs, SRAM and DRAM devices, using related, compressed vapor refrigerators with higher refrigeration capacity than the low temperature, J-T refrigerators. | Microminiature Refrigerators for Joule-Thomson Cooling of Electronic Chips and Devices | 10.1007/978-1-4613-0639-9_157 |
1990-01-01 | An extended form of the modified Enskog theory (MET) was combined with a modified volume-translated Peng-Robinson equation of state for calculating shear viscosity of mixtures of cryogenic interest. The approach presented here is an extension of the method of Sheng et al . from pure gases to mixtures without using any mixture properties. It is applied to argon, helium, neon and the three constituent binary mixtures up to a density of seven moles per liter. The average absolute percent deviations (AAPD) in the calculated pure component viscosities are less than 0.2%. For mixtures, the predicted results indicate AAPD values less than 0.5%. In addition, the AAPD values in the predicted molar volumes for mixtures are less than 1 %. | Calculation of Shear Viscosity of Mixtures by Means of an Equation of State | 10.1007/978-1-4613-0639-9_181 |
1990-01-01 | This paper discusses retractable gas cooled leads for the ASTROMAG experiment superconducting solenoid which will operate on the space station. The ASTROMAG magnet will be cooled by superfluid helium pumped from a storage tank by a fountain effect pump. Since it is desirable to keep the helium consumption low, retractable gas cooled leads are proposed for the ASTROMAG magnet. These leads, which will be in the cryostat vacuum space, will connect directly with the helium flow circuitry which cools the magnet. The leads will operate in a flow circuit separated from the shields. | Retractable Gas Cooled Leads for Astromag | 10.1007/978-1-4613-0639-9_94 |
1990-01-01 | Helium | 10.1007/978-1-4613-0673-3_30 | |
1990-01-01 | A newly developed system to measure the cryogenic creep is presented. The system adopts a laser light interference method, thereby making it possible to detect an absolute value of microscopic movement of a specimen at cryogenic temperature without any calibrations on both temperature and strain. Preliminary tests of the system and relatively short term tests of cryogenic creep on polytetrafluoroethylene (PTFE) were carried out. We consequently confirmed the measurement accuracy, and also confirmed that this high-resolution instrumentation allows the observation of creep characteristics in microscopic details. | Cryogenic Creep Measurement System Using Laser Light Interference | 10.1007/978-1-4613-0639-9_189 |
1990-01-01 | The equilibrium pressures and compositions have been measured for a system of finely powdered manganese nitride (Mn_xN_y, with x and y variable) and nitrogen gas at 650, 700, 800, and 850°C for various nitrogen loadings. Pressures ranged from less than 0.02 MPa at 650°C to 6.38 MPa at 850°C. Analysis of the test results has shown that under certain conditions Mn_xN_y could potentially be used in a triple regenerative sorption compressor refrigeration system, but the potential power savings are small compared to the increased complexity and reliability problems associated with very high temperature (>950°C) pressurized systems. | Sorption J-T Refrigeration Utilizing Manganese Nitride Chemisorption | 10.1007/978-1-4613-0639-9_164 |
1990-01-01 | Recent trends in state-of-the-art infrared space-based detection instruments favor larger focal planes for increased resolution without requiring excessive scan rate, unrealistically short sample times, and large apertures. By nature, longer wavelength IR detectors also require cryogenic cooling for useful operation. The demands placed on the cooling system are stringent and scale with focal plane size. This paper provides a description of the focal plane requirements from the point of view of the thermal designer, assesses the various thermal loads as a function of size, and examines practical thermal issues. | Cooling of Very Large Focal Plane Arrays | 10.1007/978-1-4613-0639-9_104 |
1990-01-01 | This paper reviews the development of the three types of pulse tube refrigerators: basic, resonant, and orifice types. The principles of operation are given. It is shown that the pulse tube refrigerator is a variation of the Stirling-cycle refrigerator, where the moving displacer is substituted by a heat transfer mechanism or by an orifice to bring about the proper phase shifts between pressure and mass flow rate. A harmonic analysis with phasors is described which gives reasonable results for the refrigeration power yet is simple enough to make clear the processes which give rise to the refrigeration. The efficiency and refrigeration power are compared with those of other refrigeration cycles. A brief review is given of the research being done at various laboratories on both one and two-stage pulse tubes. A preliminary assessment of the role of pulse tube refrigerators is discussed. | A Review of Pulse Tube Refrigeration | 10.1007/978-1-4613-0639-9_143 |
1990-01-01 | He II cooling for Nb Ti superconducting alloys was pioneered in France 15 years ago and has been extensively developped to an industrial level by using the opportunity of large projects in which a field level around 10 Teslas was required in conjonction with very stringent operational conditions. This development was dependant upon the possibility of producing superfluid helium in unsaturated conditions near atmospheric pressure. The paper reviews the specific properties of this fluid and analyses the reasons for its particular interest in the superconductors operation. Examples of applications are described including the high field magnet of the 30 T hybrid project installed at Grenoble and the Tokamak TORE SUPRA built at Cadarache in which stagnant pressurized He II is the coolant. Design and construction aspects are discussed as well as the experience gained after several thousand hours of operation. Further development is now considered towards still larger applications such as the next step of fusion devices and accelerators for high energy physics. In such cases He II will be preferably used in forced flow conditions; for this goal, a diversified experimental program is now pursued in Europe. | Tore Supra and He II Cooling of Large High Field Magnets | 10.1007/978-1-4613-0639-9_8 |
1990-01-01 | Hydrogen | 10.1007/978-1-4613-0673-3_31 | |
1990-01-01 | The Tore Supra refrigerator is the fifth machine in the world operating at approximately 1.8 K but with a refrigeration power of 320 W at 1.75 K. Its principal characteristics are: the compression of helium at low temperature, a large number of operating modes, an entirely automatic control system. | Operational Experience with the 1.75 K Tore Supra Refrigerator | 10.1007/978-1-4613-0639-9_32 |
1990-01-01 | The international cooperation on the characterization of relevant properties of superconducting materials and those of cryogenic structural materials necessary for the construction of superconducting equipments are successfully proceeding under the framework of VAMAS intercomparison. The progress and present status of the VAMAS intercomparison are outlined in this paper. Fairly large coefficient of scatter in critical current of Nb_3Sn wires was obtained depending on the wire manufacturing process and the measurement conditions. The strain in the specimen was considered to be a major origin of the scatter in critical current. Meanwhile, relatively good agreement was obtained in the round robin test of AC loss measurement of Nb-Ti wires. The results of tensile and fracture toughness testing of SUS 316LN and YUS 170 steels at 4.2K also show rather small scatter. An intercomparison on the electrical strain gauge calibration at cryogenic temperatures has been recently initiated. | The Vamas Intercomparison in the Area of Superconducting and Cryogenic Structural Materials | 10.1007/978-1-4613-9880-6_1 |
1989-12-01 | For the trace analysis of volatile components in a nonvolatile matrix, the headspace sampling technique offers the potential to lower detection limits in GC/FTIR experiments. Optimization of chromatographic operating parameters for Headspace GC/FTIR is discussed, aiming at the best compromise between maximum chromatographic resolution and highest S/N ratio of the infrared spectra. It is shown that the combination of headspace sampling with cryogenic capillary head trapping is able to provide Headspace GC/FTIR with the best performance in terms of sensitivity and chromatographic resolution. | Optimization in equilibrium headspace GC/FTIR | 10.1007/BF02260692 |
1989-12-01 | Unification of load bearing structures of control systems for cryogenic equipment with a view to the requirements of technical aesthetics | 10.1007/BF01147853 | |
1989-11-01 | 1. Lamellar chemical inhomogeneities in hot-worked alloys bring about kinetic differences in the aging of these regions. 2. The formation of austenite in the bands at different temperatures might be used to develop articles which must function at cryogenic temperatures. | Effect of inhomogeneities on aging processes in corrosion-resistant maraging steels | 10.1007/BF00795565 |
1989-09-01 | High-frequency vibrations of gas cryogenic machines | 10.1007/BF01156020 | |
1989-06-01 | Stand and method of measuring the vibration acceleration parameters of gas cryogenic machines | 10.1007/BF01156215 | |
1989-05-01 | Aggregate modeling of the efficiency and reliability of cryogenic systems | 10.1007/BF01155861 | |
1989-05-01 | Use of tension springs in the drive of the displacement system of a cryogenic cooler | 10.1007/BF01155858 | |
1989-04-01 | Among a number of biochemical disturbances occurring in the acute phase of brain insults, the destruction of membrane phospholipids and its consequences on the function of membrane-bound proteins is likely to be one of the most important. In the cryogenic type of injury which is classically considered as a relevant animal model of brain contusive lesions in human traumatology, the initial attack of membranes could consist in a peroxidative damage triggered by blood ferrous compounds. This in turn would lead to an activation of phospholipase A_2. As a consequence of phospholipid disruption a number of enzymes involved in energy production within the mitochondria are severely impaired. Nevertheless, the level of available ATP within the cell remains normal and even higher than normal. This paradoxical finding suggests that energy utilization is even more lowered than energy production. In fact, the Na^+−K^+-ATPase activity which normally utilizes approximately 70% of the total amount of cellular energy is severely reduced. We assume that Na^+−K^+-ATPase impairment is directly responsible for the retention of intracellular Na^+ accompanied by osmotically driven water, though admittedly other biochemical disturbances, including tissue acidosis and liberation of excitatory amino-acids, would contribute to the same result [2, 9, 16]. Lastly, a striking feature of these biochemical events is the early activation of those enzymes necessary for phospholipid resynthesis. This should mean that repair processes are at work immediately after the insult allowing resumption of Na^+−K^+-ATPase function, clearing up of brain edema and restoration of cation exchanges essential for brain work. Fra le alterazioni biochimiche che si verificano nella fase acuta degli insulti cerebrali, una delle più importanti è la distruzione dei fosfolipidi di membrana. Nell'insulto di tipo criogeno, che è considerato un modello animale di lesione contusiva cerebrale nella traumatologia umana, il primo attacco delle membrane potrebbe consistere in um danno perossidativo determinato dai composti ferrosi del sangue. Ciò determinerebbe una attivazione della fosfolipasi A2. Come conseguenza della distruzione dei fosfolipidi si verifica un grave danno di numerosi enzimi impegnati in produzione di energia all'interno dei mitocondri. Pur tuttavia il livello dell'ATP disponibile all'interno della cellula rimane normale e persino più elevato del normale. Questo dato paradossale sembra suggerire che l'utilizzazione energetica è persino più ridotta della produzione di energia. Difatti l'attività delle Na^+−K^+ ATPasi che normalmente utilizzano circa il 70% del totale dell'energia cellulare è notevolmente ridotta. Noi pensiamo che l'interessamento delle NA^+−K^+ ATPasi è direttamente responsabile della ritenzione di NA^+ intracellulare associato all'acqua regolata in modo osmotico, anche se altri disturbi biochimici, tra i quali l'acidosi tissulare e la liberazione di aminoacidi stimolanti, potrebbero contribuire alla medesima conseguenza. Per ultimo una caratteristica di questi eventi biochimici è l'attivazione precoce di questi enzimi necessari per la resintesi fosfolipica. Questo sta a significare che i processi riparativi sono in atto immediatamente dopo l'insulto permettendo la ripresa funzionale della NA^+−K^+ ATPase, la risoluzione dell'edema e la riattivazione degli scambi cationici essenziali per l'attività cerebrale. | Membrane damage in acute brain trauma | 10.1007/BF02333611 |
1989-04-01 | The responses of single goldfish olfactory bulb mitral cells were studied by extracellular recordings before and during cryogenic blockade of the efferent, centrifugal pathways in the ipsilateral olfactory tract. In each experiment the same odour was presented 40 times before and then 40 times during cooling. Each stimulus period (at least 30 s) was preceded by a stimulus-free interval (at least 30 s), during which a steady stream of tap water was applied. These procedures allow the investigation of activity changes of single neurons and of cell ensembles using statistical methods. i) In comparison with the pre-cooling activity, cooling of the efferent pathways did not cause a generalized disinhibition in mitral cell responses. Significant disinhibitory, significant inhibitory and indifferent effects occurred in about the same proportion during repetitive water and odour applications. ii) Abrupt or slow changes of single mitral cell discharge patterns during the 40 water and odour applications were observed before and during blocking of the efferent fibre systems: These pattern changes are therefore not necessarily a consequence of the efferent signals, and may thus have been a result of intrabulbar plasticity. iii) The most notable effect of efferent fibre blockade across all experiments was a significant (Wilcoxon-ranktest, P = 0.01) decrease of the signal to noise ratio i.e., the ratio between the activity during the “spontaneous” (water) and the stimulus (odour) phase, which could be demonstrated for both the phasic (immediately after stimulus onset) and tonic (during long term stimulation) components of the mitral cell responses. | The effects of cryogenic blockade of the centrifugal, bulbopetal pathways on the dynamic and static response characteristics of goldfish olfactory bulb mitral cells | 10.1007/BF00247946 |
1989-02-01 | Bond between a reinforcement bar and concrete at normal and cryogenic temperatures | 10.1007/BF00730707 | |
1989-02-01 | Vibroprotection as a method of reducing transport losses of cryogenic liquids | 10.1007/BF01245852 | |
1989-02-01 | The substantial influence of liquid-nitrogen vaporization from Kh-34B vessels on cryogenic precipitates, the coating of screens with an adsorbent dust, and the destruction of the intermediate SVTI material has been experimentally established. Methods are proposed and have been tested to eliminate the effects of these factors on vaporization. | Determining and eliminating factors impairing the efficiency of cryogenic vessels | 10.1007/BF00870576 |
1989-01-01 | Advanced composite structures are currently being utilized in numerous cryogenic systems. They offer low thermal conductivity, high strength and stiffness, lightweight, low outgassing, integral fittings, and other advantages. Several types of fibers and resins are available to meet extreme structural and thermal requirements. Typical properties for filament wound composite laminates are provided. Design considerations for various configurations, such as straps, tubes, and struts, are discussed. Typical applications are dewars for spacecraft, coolers for satellite instruments, and superconducting magnets for medical imaging and high-energy physics. The cryostat developed by Fermi National Accelerator Laboratory for the SSC dipole magnets has advanced composite support posts and anchor tie bars. | Advanced Composite Structures for Superconducting Super Collider | 10.1007/978-1-4613-0841-6_49 |
1989-01-01 | The cooling of cryogenic liquids by the pumping-out of vapor is considered theoretically, taking account of the variability of the thermodynamic properties, the heat fluxes to the cryostatting zone, and the specific heat of the vessel walls. | Cooling of cryoagents by the pumping-out of vapor | 10.1007/BF00870462 |
1989-01-01 | The laser spectroscopy of leptonic atoms is of interest because of the simplicity of the atoms. Leptons possess no known structure. Unlike the hydrogen atom with its complicated and poorly understood proton, the behavior of leptonic atoms should in principle be calculable to much greater precision. In the case of muonium, the theoretical uncertainty will be limited by our knowledge of fundamental constants such as m_ μ /m_p and α. Given the 72 kHz linewidth of the 1S state due to the 2.2 μ sec lifetime of the muon, one can ultimately expect a measurement of the 1S–2S splitting better than Δ ν / ν < 10^3 Hz/10^15 Hz = 10^−12. In the case of positronium, the 140 nsec lifetime should lead to an ultimate precision of Δ ν / ν = 10^−11. Thus, this system provides a unique opportunity for the precise study of a purely leptonic two-body system, and QED corrections to that system. In addition to QED tests, the laser excitation of these atoms could provide thermal, sub-thermal, and eventually cryogenic sources of positrons and muons that can be used in a variety of applications. | Laser Spectroscopy of Positronium and Muonium | 10.1007/978-3-642-88421-4_14 |
1989-01-01 | The SSC is an application of superconductivity on a scale vastly larger than any before. Its two collider storage rings are formed of some 10,000 superconducting magnets of many types, all of which must be maintained below the chosen operating temperature of 4.35 K under a wide variety of operating conditions. Thus an extensive cryogenic system is required that not only meets the magnets’ operating requirements, but also provides for transient conditions such as cooldown, magnet quench, and periods for magnet maintenance. In addition, this system must function compatibly with scientific use of the SSC and run on a schedule consistent with the high beam availability that is necessary to the success of the SSC as a whole. | SSC Refrigeration System Design Studies | 10.1007/978-1-4613-0841-6_28 |
1989-01-01 | To study the operation of the Superconducting Super Collider (SSC) cryogenic system during transient operating conditions, we have developed and programmed in FORTRAN, a time-dependent, nonlinear, homogeneous, lumped-parameter simulation model of the SSC cryogenic system. This dynamic simulator has a modular structure so that process flowsheet modifications can be easily accommodated with minimal recoding. It uses the LSODES integration package to advance the solution in time. For helium properties it uses Air Products’ implementation of the standard thermodynamic model developed by the NBS. Two additional simplified helium thermodynamic models developed by Air Products are available as options to reduce computation time. To facilitate the interpretation of output, we have linked the simulator to the Speakeasy conversational language. We present a flowsheet of the process simulated, and the material and energy balances used in the engineering models. We then show simulation results for three transient operating scenarios: startup of the refrigeration system from standby to full load; the loss of 4K refrigeration caused by the tripping of one of two parallel compressors in a sector; and a full-field quench of a single magnet half-cell. We discuss the response of the fluid within the cryogenic circuits during these scenarios. | Dynamic Modeling and Simulation of the Superconducting Super Collider Cryogenic Helium System | 10.1007/978-1-4613-0841-6_29 |
1989-01-01 | Multilayer insulation (MLI) is employed in cryogenic devices to control the heat load of those devices. The physics defining the thermal performance of an MLI system is extremely complex due to the thermal dynamics of numerous interdependent parameters which in themselves contribute differently depending on whether boundary conditions are transient or steady-state. The Multilayer Insulation system for the Superconducting Super Collider (SSC) consists of full cryostat length assemblies of aluminized polyester film, fabricated in the form of blankets, and installed as blankets to the 4.5K cold mass, and the 20K and 80K thermal radiation shields. Approximately 40,000 blankets will be required in the 10,000 cryogenic devices comprising the SSC accelerator. Each blanket will be nearly 56 feet long by 6 feet wide and will consist of as many as 32 reflective and 31 spacer layers of material. Discussed are MLI material choices, and the physical parameters which contribute to the operational performance of MLI systems. Disclosed is a method for fabricating MLI blankets by employing a large diameter winding mandrel having a circumference sufficient for the required blanket length. The blanket fabrication method assures consistency in mass produced MLI blankets by providing positive control of the dimensional parameters which contribute to the MLI blanket thermal performance. The fabrication method can be used to mass produce prefabricated MLI blankets that by virtue of the product have inherent features of dimensional stability, three-dimensional uniformity, controlled layer density, layer-to-layer registration, interlayer cleanliness, and interlayer material to accommodate thermal contraction differences. | Multilayer Insulation (MLI) in the Superconducting Super Collider — A Practical Engineering Approach to Physical Parameters Governing MLI Thermal Performance | 10.1007/978-1-4613-0841-6_45 |
1989-01-01 | Dioscorea belongs to the monocotyledons, family Dioscoreaceae, subfamily Dioscoreoideae. It comprises ca. 600 species and is divisible into numerous sections according to stem twining, leaf morphology, inflorescences, seed wings, bulbil formation, tuber morphology and chemical content (Dahlgren et al. 1985). Bulbils occur in the leaf axis of numerous species of Dioscorea and contribute greatly to vegetative propagation. Flowers are dioecious and seeds often winged. |
Dioscorea: In Vitro Culture and the Micropropagation of Diosgenin-Containing Species | 10.1007/978-3-642-73617-9_10 |
1989-01-01 | The date palm [ Phoenix dactylifera L. (2n = 36)] is one of the most important members of the Palmae (Arecaceae) family. There are 11 other species in the genus Phoenix , some of which are used as ornamentals, e.g. P. canariensis Chabaud, whilst P. sylvestris (L.). Roxb. is cultivated in India as a source of sugar. All species of Phoenix are dioecious with male and female flowers produced in clusters on separate palms in the axils of leaves from the previous year’s growth. | Date Palm (Phoenix dactylifera L.) | 10.1007/978-3-642-61535-1_9 |
1989-01-01 | The technical and economical advantages of the underground storage of petroleum products have, over the last few decades, made it possible to provide a particularly attractive alternative to open-air storage tanks for most petroleum products. | Underground Storage of Liquefied Gases at Low Temperature | 10.1007/978-94-009-0993-9_15 |
1988-11-01 | Effect of cryogenic temperatures on the static and cyclic strength of the parent metal and welded joints in 1201 aluminum alloy | 10.1007/BF01530141 | |
1988-11-01 | Strength of welded joints of glass with metal at cryogenic temperatures | 10.1007/BF01530143 | |
1988-10-01 | Dynamic characteristics of turbine-type flowmeters for cryogenic fluids | 10.1007/BF00864879 | |
1988-09-01 | Superconductors and Beyond: Cryogenics in Industry | 10.1007/BF03258560 | |
1988-09-01 | Pressure fluctuations in cryogenic systems | 10.1007/BF01147284 | |
1988-09-01 | Microbiological Materials Processing | 10.1007/BF03258559 | |
1988-08-01 | Cryogenic methods of evacuation: Operating experience and prospects | 10.1007/BF01149203 | |
1988-06-01 | Experimental cryogenic effects on the coronary arteries | 10.1007/BF00842157 | |
1988-04-01 | Reduction of vibrations in gas cryogenic machines | 10.1007/BF01837181 | |
1988-04-01 | Methods for raising the efficiency of cryobiological vessels with liquid nitrogen are proposed and realized, and a method for calculating their heat-shielding is developed and tested. | Efficiency of “shieldless” method of employing the cold of vapors in cryogenic vessels with a wide neck | 10.1007/BF00871115 |
1988-03-01 | Nonsteady-state evaporation of a cryogenic liquid into the atmosphere | 10.1007/BF00749192 | |
1988-03-01 | Combustion of gasless systems at cryogenic temperatures | 10.1007/BF00749193 | |
1988-03-01 | A system has been developed for rapid measurement of the torsional properties of organic-matrix composite materials at temperatures from 4 to 295 K. It offers ease of construction, simplicity of specimen design, small specimen size, rapid specimen turnaround, and low consumption of cryogens. In addition to providing quantitative data on the modulus of rupture and of rigidity, the strain-control feature facilitates analysis of the stress-displacement curve in the region where damage is occurring, providing useful information on the influence of various parameters on the failure mode. The system was optimized for rapid screening of the influence of component variables on the performance of electrical insulators required to function in the cryogenic irradiation environment of superconducting magnets in magnetic fusion energy systems. However, it is also useful in studying the influence of cryogenic environment on unreinforced polymers and on metals and alloys. | Strain-controlled torsional test method for screening the performance of composite materials at cryogenic temperatures | 10.1007/BF01153974 |
1988-02-01 | 1. In the temperature range with which deformation does not cause formation of α-phase for Fe-Ni-Co alloys, a reduction is observed in the thermal linear expansion nature is evidently connected with the Invar anomaly. 2. In alloy 29NK at −70°C as a result of extension α-phase occurs (30% in the overall volume and 59% at the area of a break). 3. Alloy 32N14K showed high stability towards γ→α-transformation with deformation over the whole cryogenic temperature range down to −269°C. Precipitation of α-phase is only observed in the area of a specimen break at temperatures below −196°C where the degree of deformation ε=55%. This alloy may be used for articles operating under load at temperatures down to −269°C. | Effect of deformation on the structure and properties of alloys of the system Fe-Ni-Co | 10.1007/BF00777823 |
1988-02-01 | Unilateral cryogenic lesions of the brain were produced in mice by applying the face of the brass rod cooled in liquid nitrogen to the exposed parietal bone. As a result of the cryogenic lesion, the mast cells in the dura mater underlying the parietal bone were disrupted. This disruption of dural mast cells was accompanied by a significant increase in the histamine content within the cryogenically injured cerebral cortex. However, when similar lesions were produced in mice which are deficient or lacking in mast cells, this increase in cerebral cortical histamine did not occur. Thus, the cryolesion-induced elevation of cerebral cortical histamine apparently depends on the release of histamine from mast cells located near the injured cerebral cortex. The significance and role(s) of the lesion-induced elevation of this potent biogenic amine and putative neurotransmitter is presently unknown, but may involve alteration of the blood-brain barrier, vasomotor activity of the cerebrovasculature and/or other sequelae to brain injury. | Cryogenic lesions induce a mast cell-dependent increase in cerebral cortical histamine levels in the mouse | 10.1007/BF03160134 |
1988-01-01 | The HERA-superconducting proton ring magnet system, part of a 820 GeV proton/30 GeV electron colliding beam facility at DESY, Germany, will be cooled by a helium liquefier/refrigerator as described previously. The refrigerator has been specified by DESY, detailed design, fabrication and assembly have been executed by industry. All assembly work was finished by April 1987. A short description of the final design of the plant is given. Some first results of performance tests as values for refrigeration power at 4.4 K and between 40 K and 80 K as well as liquefaction rates at 4.4 K with one coldbox system out of three will be presented. Preliminary values for efficiencies of cold-boxes and compressor groups are calculated. | Performance Test of the Hera 3 × 6500 w Helium Refrigeration Plant | 10.1007/978-1-4613-9874-5_68 |
1988-01-01 | The SCRIBE (Stratospheric CRyogenic Interferometer Balloon Experiment) system was flown August 10, 1986, over eastern New Mexico. Because the SCRIBE sensor is a liquid nitrogen cooled interferometer, absolute radiance data were obtained with good resolution (0.1 cm^−1) and high sensitivity. The normal field of view was reduced to ~0.2° (80 m on the ground) by a 12′' Dall-Kirkham telescope, and was steered by remote control using television cameras boresighted with the infrared sensor. The stabilized viewing allowed “staring” at selected features for considerable periods of time. The data sets thus include spectra of different terrain features, as well as substantially different atmospheric paths to one feature. Both the data and the SCRIBE equipment are described. | Observation of upwelling radiation by SCRIBE | 10.1007/BF01349803 |
1988-01-01 | Developing a cooling method of far-infrared detectors in micro-gravity circumstances in the 0.1 K region, we have designed a new adiabatic demagnetization cryostat and improved a fabrication method of magnetic salt. The cryostat was designed for laboratory use (under 1 G), however most thermal conditions were planned for use in space. An optical window was prepared for the real combination with detector element. The measured heat leak was about 130 mW which enabled us to operate the cryostat more than 50 hours. Low operating current superconducting magnet which was indirectly cooled by liquid helium, was mounted on the cryostat. The magnetic field of 3 T was obtained by current of 11.5 A. The success of the magnet guaranteed the system to work in space where fluid interfaces are not clear. Manganese ammonium alum was grown from the saturated solution and purified. | New Design of an Adiabatic Demagnetization Cryostat for Space Application | 10.1007/978-1-4613-9874-5_106 |
1988-01-01 | A multipurpose cryogenic testing facility was constructed and became operational in 1986 at Fermilab. It consists of a standard Tevatron satellite refrigerator and 450 liter subcooling dewar housed within a building adjacent to a Tevatron refrigerator. A 11 m by 15 m high bay contains power supplies necessary to power Superconducting Super Collider (SSC) magnets, a cryogenic feedcan to interface the refrigerator to the magnet string, and an area for testing Tevatron components. Currently, a 120 m, 4 m diameter tunnel has been constructed off the high bay to house a half cell of SSC Design D magnets. Capabilities have made to extend the tunnel up to 1 km in length. Testing at the facility includes: SSC long string test, heat leak measurement, cold compressor tests, turbine test, and cold leak checking. | Cryogenic Testing at the SSC String Test Facility | 10.1007/978-1-4613-9874-5_70 |
1988-01-01 | We are developing a quench detecting technique using a dual-core optical fiber. The fiber has two single-mode optical cores in one fiber. Using this technique, we have demonstrated that a temperature rise of 1.0 K at 4.2 K, so that, a quench in a superconducting magnet was detectable. We verified that an electromagnetic force-stress to the optical fiber did not deteriorate the sensitivity of the quench detection. A quench detector using this optical method is immune from electromagnetic noises and free from troubles caused by high voltage tension. Problems arising when applying this technique to a large scale magnet and a possible improving technique in the instrumentation are discussed. | Quench Detection of Superconducting Magnet by Dual-core Optical Fiber | 10.1007/978-1-4613-9874-5_35 |
1988-01-01 | The cryogenic system for the Mirror Fusion Test Facility (MFTF) is a 14-kW, 4.35-K helium refrigeration system that proved to be highly successful and cost-effective. We were able to meet all operating objectives, while remaining within a few percent of our initial cost and schedule plans. The management approach used in MFTF allowed us to make decisions quickly and effectively, and it helped keep our costs down. Manpower levels, extent and type of industrial participation, key aspects of subcontractor specifications, and subcontractor interactions are reviewed, as well as highlights of the system tests, operation, and present equipment status. Organizations planning large, high-technology systems may benefit from our experience with the MFTF cryogenic system. | The Mirror Fusion Test Facility Cryogenic System — Performance, Management Approach, and Present Equipment Status | 10.1007/978-1-4613-9874-5_71 |
1988-01-01 | The TOPAZ superconducting solenoid is cooled with forced two phase helium since it is large in size (2.9 m in diameter, 5.1 m in length) and a thin configuration. A cooling pipe, 18 mm in diameter and 150 m in total length, is wound around the superconducting coil. The relation between the helium mass flow rate and pressure drop through the magnet was obtained by a liquid helium pump which has a capacity of 300 1/h. The quality of helium in the cooling pipe was calculated from the mass flow rate and heat input to the solenoid. The pressure drop of the two phase helium flow was estimated for the case of (1) a homogeneous flow model and (2) a separated flow model. Experimental results agreed with the theoretical results of the homogeneous model. Also, the flow pattern in the cooling pipe was estimated as “stratified flow” on the Baker-diagram of helium. | Pressure Drop in Forced Two Phase Cooling of the Large Thin Superconducting Solenoid | 10.1007/978-1-4613-9874-5_66 |
1988-01-01 | The cryogenic system of the AMY superconducting solenoid magnet was designed, constructed and tested. The coil has a diameter of 2.5 m, a length of 1.5 m and a cold mass of 17 tons (CU/SUS). It iscooled with a pool-boiling method by immersion in a liquid helium bath of 500 liters. In the initial cooling test, the magnet was successfully cooled down within 7 days by a helium refrigerator with a rated cooling capacity of 100 1/h (300 W at 4.4 K). The refrigerator and magnet were fully controlled by an industrial-use computer system. The coefficient of performance (COP) of the refrigerator (Q_r/W_c) was also measured as 0.00135 with liquid nitrogen consumption of 70 1/h. | Cryogenic System of a 3 Tesla Superconducting Solenoid for the AMY Particle Detector at Tristan | 10.1007/978-1-4613-9874-5_67 |
1988-01-01 | The superconducting RF cavities (32 × 5 cell) will be installed in TRISTAN electron-positron collider at KEK to upgrade the electron-positron beam energy up to 33 GeV × 33 GeV. Two 5-cell cavities are coupled together, enclosed in a cryostat and cooled by liquid helium pool boiling. Cryogenic system for the superconducting RF cavities was designed. The capacity of helium refrigerator is 4 kW at 4.4 K with liquid nitrogen precooling and two expansion turbines. The present system is designed to be easily upgraded to 6.5 kW without liquid nitrogen with an addition of expansion turbines and compressors. | Cryogenic System for Tristan Superconducting RF Cavity | 10.1007/978-1-4613-9874-5_75 |
1988-01-01 | The realization that water ice is the major constituent of comets, the satellites of the outer planets and their rings particles, and of the icy grain mantles in dense interstellar clouds, prompted us to study in detail the properties of water ice at very low temperatures, with an emphasis on its ability to trap various gases (Bar-Nun et al., 1985; Laufer et al., 1987). The experimental setup and procedure will be described here only briefly: The test chamber and its pump consisted of two 10-in cryogenic pumps, connected head-on by a 6-in gate valve. After rough pumping the chamber to 10^-4 Torr by a sorption pump, the pressure in it was lowered to better than 10^-8 Torr by the cryogenic pump. A thick 5 by 2.5 cm gold-coated copper plate was cooled cryogenically (by the chamber's cold finger) to ∼ 19 K, and its temperature could be controlled by heating, between 19 and 250 K, within ±1 K. A stream of water vapor, from a reservoir of throughly degassed triple-distilled water, was directed at the plate, through a capillary tubing with a diffuser on its tip. An ice layer, consisting of 10^19 – 10^20 water molecules was deposited on the plate during ∼ 45 min. A stream of gas (Ar, CO, N_2, CH_4, H_2, D_2 or Ne) was then directed at the ice, through the same capillary tubing, at a pressure between 8 . 10^-8 and 0.1 Torr, for several minutes, keeping the gate valve fully open. Alternatively, a premixed gas-water vapor mixture was flowed on the cold plate and was codeposited on it. When the deposition was termined, the chamber was pumped for ∼ 10 min, unit a constant pressure of ∼ 10^-8 Torr was reached. The plate was then uniformly warmed, at a costant rate of 0.1–3 K min^-1. The evolution of gas and water vapor from the ice was monitored by a precalibrated quadrupole mass filter and the amounts of gas and water vapor emerging at each temperature range were obtained by integrating their fluxes over the time of their evolution from the ice. | The Structure and Dynamics of Amorphous Water Ice and Trapping of Gases in It | 10.1007/978-94-009-3033-9_9 |
1988-01-01 | The proton storage ring of HERA will contain 422 superconducting dipole magnets^1 and 224 superconducting quadrupole magnets.^2 At the newly constructed HERA magnet measurement facility, each of the superconducting magnets will be individually tested before being installed in the 6-km ring tunnel. This paper describes the design and initial operation of the helium cryogenic distribution system that allows independent testing of the HERA cold-iron magnet. Operation of each magnet at liquid helium temperature insures the quality of the magnetic characteristics and the cryogenic performance. Six test stands are completely instrumented to monitor the cryogenic conditions of the magnet under test. A process-control computer system is used to record the measurements and automate the cryogenic operation of the measurement facility. Helium for magnet testing is supplied by one of the 6.5-kW helium refrigerators for HERA. A large, helium subcooler is included in the measurement facility to produce the correct operating temperature at the test stands. The performance of the cryogenic system and the schedule for magnet testing are discussed. | Cryogenic Experience at the Hera Magnet Measurement Facility | 10.1007/978-1-4613-9874-5_69 |
1988-01-01 | The use of cryogenic temperatures is an option being considered more frequently as a means to enhance the performance of electronic systems. A basic issue in obtaining the benefits of lower operating temperature is integrating the cooling system with the electronic system—what does the electronics community need and what can the cryogenics community provide? This panel will address the engineering issues involved, with emphasis on refrigeration for computer systems operating in the liquid-nitrogen temperature range. | Refrigeration for Electronics: Summary of a Panel Session | 10.1007/978-1-4613-9874-5_83 |
1988-01-01 | Current, amplification, output power and frequency limits of field-effect transistors (FETs) are determined by both the carrier concentration and the carrier transport properties (mobility and velocity) in the channel. In GaAs MESFETs the current conducting channel itself is doped with shallow impurities up to levels of 10^17 or 10^18 cm^-3. These high concentrations degrade the mobility. | Shallow and Deep Impurity Investigations: The Important Step Towards a Microwave Field-Effect Transistor Working at Cryogenic Temperatures | 10.1007/978-1-4684-5553-3_11 |
1988-01-01 | In support of NASA’s Superfluid Helium On-Orbit Transfer (SHOOT) Flight Experiment, two pumping approaches are being evaluated. NASA-GSFC is conducting tests on the thermomechanical (TM) pump while NASA-ARC is sponsoring tests on a centrifugal pump at the NBS Cryogenic Laboratory. For either of these approaches, a common concern is the method that should be employed for fluid acquisition. While technology is available for design, fabrication, and operation of fluid acquisition systems with conventional fluids, performance with superfluid helium (SFHe) is uncertain. As a result, Martin Marietta joined with NASA to investigate the use of capillary acquisition systems. Assurance is needed that the devices will work with superfluid helium under an adverse 10^−4g operational environment. Minus one-g outflow tests were conducted with SFHe in conjunction with the TM pump set-up in the Cryogenic Laboratories at GSFC. Both fine mesh screen and porous sponge systems were tested. A screen acquisition device was also tested with the low-NPSH centrifugal pump. Results to date show that the screen and sponge are capable of supplying SFHe to the TM pump inlet against a one-g head up to four cm which is more than sufficient for the SHOOT application. Results with the sponge are reproducible while those with the screen cannot always be repeated. Further tests to characterize these systems are required. | Acquisition System Testing with Superfluid Helium | 10.1007/978-1-4613-9874-5_110 |
1988-01-01 | A computer control system for the helium refrigerators of the TRISTAN detector magnets (VENUS, TOPAZ, and AMY) was designed and constructed for the purpose of centralized and automatic operation. The control system of these helium refrigerators is programmed to do a series of procedure automatically in order to simplify the operation. The system is also programmed to meet emergencies such as a power failure or a magnet quench, in order to guarantee the long-term operation without trouble. Each part of the system was tested and confirmed to work well after some modifications. All helium refrigerators have been operated together using the centralized control station from January, 1987. | Control System for Helium Refrigerators of Tristan Detector Magnets | 10.1007/978-1-4613-9874-5_133 |
1988-01-01 | The discovery of superconductivity with T_c > 77 K (liquid nitrogen boiling temperature) is potentially of great importance for large scale electric utility applications such as the transmission and storage of electrical energy. Superconducting magnetic energy storage (SMES) is already a promising technology for electric utility load leveling. Therefore, it is useful to assess SMES with oxide superconductors cooled by inexpensive and plentiful liquid nitrogen (LN_2) instead of NbTi cooled by the more expensive liquid helium. Liquid nitrogen cooling will significantly reduce the refrigeration energy requirements, and, especially, would help make small size SMES units more economic. The paper presents the impact of LN_2 on efficiency, design and economics of SMES. | The Potential Impact of Developing High T_C Superconductors on Superconductive Magnetic Energy Storage (SMES) | 10.1007/978-1-4613-9874-5_9 |
1988-01-01 | Cryogenic instrumentation is becoming more common in the hospital environment. Led by MRI magnets, cryocoolers as well as large amounts of liquid helium and liquid nitrogen are being used in both mobile and fixed installations. Liquid helium is also necessary in the use of SQUID instrumentation. Different methods of attaining low temperatures are compared as to their technical advantages and disadvantages, cost and reliability. Possible new high temperature superconductors would have a considerable impact on dewar systems as well as on changing the emphasis of cryogenic refrigerators and liquid cryogens to temperatures associated with liquid neon, nitrogen or even freon. | Cryogenic Requirements for Medical Instrumentation | 10.1007/978-1-4613-9874-5_11 |
1988-01-01 | The SHOOT flight demonstration is being undertaken to verify component and system level technology necessary to resupply large superfluid helium dewars in space. The baseline configuration uses two identical 210 liter dewars connected by a transfer line which contains a quick disconnect coupling. The helium will be transferred back and forth between the dewars under various conditions of flow rate, parasitic heat load, and temperature. An astronaut Extra-vechicular Activity (EVA) is also planned to manually demate and mate the coupling. A number of components necessary for the flight are being developed. These components are described here. | The Superfluid Helium On-Orbit Transfer (Shoot) Flight Experiment | 10.1007/978-1-4613-9874-5_108 |
1988-01-01 | The superconducting proton storage ring of the HERA project at DESY (Hamburg) will contain 422 dipole — and 224 quadrupole magnets. The magnets will be installed in the 6.3-km ring underground. Three refrigerators produce supercritical helium, which is fed into a transferline that supplies individual sections of the ring. Another transferline provides helium for the magnet test facility. All cryogenic installations will be controlled by a process control computer system. This paper describes some of the experience during specification, installation and the first running period of the system installed at DESY. Individual solutions for distributed process controls, low temperature measurements and some utilities are presented. | Experience with a Process Control System for Large Scale Cryogenic Systems | 10.1007/978-1-4613-9874-5_134 |
1988-01-01 | The D-Zero liquid argon collider calorimeter has been designed for high energy particle physics experimentation as an integral part of the Tevatron accelerator/collider. The high density, hermetic, 125,000 channel calorimeter is an assembly of three axial, cylindrical, 20m^3 liquid argon cryostats containing 770 tonnes of calorimeter modules comprised of uranium and copper absorber plates and multilayer signal boards. The 228t end calorimeter cryostats can be moved 1.3m axially, while full and operable, to allow access to a Central Tracker mounted in the warm bore of the central calorimeter. The liquid argon is stored 13m below ground at detector-level in a 76m^3 storage dewar. Refrigeration for the argon in the cryostats and the dewar is provided by liquid nitrogen stored in a 76m^3 dewar located at ground-level. Special vent and spill sump provisions allow personnel to work within the detector platform below the cryostats and in the accelerator tunnel. After completion of testing in the assembly hall position, the entire 4550t detector is rolled 40m into the collision hall for each running period. Cooldown, warmup, and control and operation of the cryogenic systems of the detector are described. | Cryogenic Design of the D-Zero Liquid Argon Collider Calorimeter | 10.1007/978-1-4613-9874-5_135 |
1988-01-01 | The CEBAF superconducting linear accelerator^1 requires a 4.8KW cryogenic system to operate 418 superconducting r.f. cavities^2 at 2.0K. The cavities are assembled into 53 cryomodules which are stand alone cryostats. The cryomodules are made up of four cryounits, each containing two r.f. cavities. CEBAF’s three experimental halls will be equipped with superconducting magnet particle spectrometers, and a superconducting 4π toroidal spectrometer. The refrigeration loads, capacities and design will be discussed and considerations for the 2K operation temperature will be developed. The operating scenario, the distribution system that is integrated with the cavity cryostat design, and the experimental hall cryogenic system will be presented. | Cebaf’s Cryogenic System | 10.1007/978-1-4613-9874-5_76 |
1988-01-01 | A small high vacuum valve has been built for use in a liquid hydrogen handling system. The valve stem tip consists of a polycarbonate resin which closes against a stainless steel seat. Other features of the valve include a closing mechanism that is helium gas operated and a bellows stem seal that allows the valve to open and close without changing the internal volume. | A Miniature Cryogenic High Vacuum Valve | 10.1007/978-1-4613-9874-5_139 |
1988-01-01 | During the next 10 years several space missions will require superfluid helium replenishment at two or three-year intervals to extend their lifetimes. A shuttle experiment is in hardware development which will demonstrate many of the key components including fluid pumps, acquisition devices, flowmeters, quick disconnect EVA couplers and process controllers. The experiment will consist of a series of transfers between two 200-liter dewars. This paper describes the design, analysis and trades conducted for the external thermal design of the dewars and support electronics as well as the optimization and prediction of the dewar and cryostat assembly performance. Of particular importance in the analysis are the ground hold and standby performance of the dewars as well as the temperature of the helium bath during high flow rate transfers. The Hitchhiker carrier is a flight of opportunity and the exact orbit inclination and shuttle profiles will not be known until approximately one year before launch. As a result, the external thermal design focused on the stability of the dewar, transfer line, and electronics temperatures in a number of representative orbits. | Cryogenic and Thermal Design for the Superfluid Helium On-Orbit Transfer (SHOOT) Experiment | 10.1007/978-1-4613-9874-5_109 |
1988-01-01 | The potential for in-flight replenishment of liquid helium for future systems such as the Space Infrared Telescope Facility has triggered vast interests in the fountain effect pumps (FEP’s). The purpose of this paper is to correlate the FEP data in literatures under a common frame of reference. An empirical equation is proposed that can predict the performance of both the heater activated pumps and the cooler activated devices. According to the present findings, there is a throughput factor associated with each porous material. This throughput factor is inversely proportional to the square root of the Darcy permeability (K). The proposed equation and the correlation of the throughput factor is very useful for the design of FEP’s. For a given porous medium used for FEP, one can easily predict its performance if the permeability of that material is measured. | The Design of Fountain Effect Pumps | 10.1007/978-1-4613-9874-5_56 |
1988-01-01 | A specially designed liquid helium flow cryostat for irradiating Nb_3Sn specimens below 20K with fusion (14.6 MeV) neutrons at the Rotating Target Neutron Sorce (RTNS-II) in Livermore and subsequent in-situ measurements of the critical parameters Tc and j_c in magnetic fields up to 15.6 T has been employed in recent experiments. After each irradiation cycle, the flow cryostat was removed from the target without warmup and inserted into a split superconducting solenoid, field enhanced by holmium flux concentrators. This work emphasizes engineering aspects of the cryogenic system, the technical constraints encountered during design and, finally, its performance under operating conditions. | A Cryogenic System for Fusion Neutron Irradiation and In-Situ Measurements on Superconductors | 10.1007/978-1-4613-9874-5_78 |
1988-01-01 | 4 K Gifford McMahon (GM)/Joule Thomson (J-T) cycle refrigerators are the most commonly used type of closed cycle refrigerator for applications requiring 1 to 4 watts of refrigeration. This paper describes the evolution of this type of refrigerator, its characteristics, application considerations, and gives examples of current applications with emphasis on recondensing helium in Magnetic Resonance Imaging (MRI) cryostats. | 4 K Gifford Mc Mahon/Joule-Thomson Cycle Refrigerators | 10.1007/978-1-4613-9874-5_84 |
1988-01-01 | Airborne C_1- and C_2-halocarbons can be determined by cartridge sampling, gas chromatography and electron capture detection. High accuracy is achieved in the concentration range typical for rural and forest air, when the following components of the analytical train are meticulously optimized: enrichment on adsorption cartridges, thermodesorption, cryofocussing, capillary gas chromatography and electron capture detection. The parameters associated with sample collection, i.e. type and properties of adsorbent, dimensions and design of the cartridge, temperatures, and gas flows must be judiciously balanced under consideration of the prevalent air concentrations and the dynamic range of the ECD, in order to achieve standard deviations of 10% or less for replicate analyses. | Optimization of the gas-chromatographic determination of airborne halocarbons | 10.1007/BF00470626 |
1987-12-01 | Following cryogenic lesions of the brain in the rabbit, ictal activity appears within min with a maximum at 2 h. Brain edema increases rapidly between 2–4 h with a maximum at 8 h. The glutamate concentration reaches 209% of control in the perilesional area at 2 h and the time course of glutamate/GABA ratio parallels the time course of epileptic activity. The impairment of Na^+−K^+-ATPase activity (rise of K_Mapp for K^+) in the glial fraction coincides with the increase of edema. A positive correlation is found between the total amount of ictal activity and the total amount of edema in individual animals, suggesting that epilepsy may enhance edema formation. | Relationship between epileptic activity and edema formation in the acute phase of cryogenic lesion | 10.1007/BF03160181 |
1987-11-01 | Metrological equipment for checking means of measuring magnetic fields under normal and cryogenic conditions | 10.1007/BF00865058 | |
1987-10-01 | Cryogenic properties of a P/M Ni_3Al-B alloy | 10.1007/BF02646213 | |
1987-10-01 | The cryogenic mechanical properties of aluminum-lithium alloys are of interest because these alloys are attractive candidate materials for cryogenic tankage. Previous work indicates that the strength-toughness relationship for alloy 2090-T81 (Al-2.7Cu-2.2Li-0.12Zr by weight) improves significantly as temperature decreases. The subject of this investigation is the mechanism of this improvement. Deformation behavior was studied since the fracture morphology did not change with temperature. Tensile failures in 2090-T81 and -T4 occur at plastic instability. In contrast, in the binary aluminum-lithium alloy studied here they occur well before plastic instability. For all three materials, the strain hardening rate in the longitudinal direction increases as temperature decreases. This increase is associated with an improvement in tensile elongation at low temperatures. In alloy 2090-T4, these results correlate with a decrease in planar slip at low temperatures. The improved toughness at low temperatures is believed to be due to increased stable deformation prior to fracture. | Mechanical behavior of aluminum-lithium alloys at cryogenic temperatures | 10.1007/BF02646201 |
1987-08-01 | A new procedure for obtaining density-dependent mixing rules is applied to the Soave-Redlich-Kwong equation of state. The result is a one-parameter local-composition mixing rule which adequately represents the nonidealities possible in dense fluid mixtures but approaches the classical mixing rule at low densities. A three-parameter version of the mixing rule is also presented which allows for the local-composition effect in the low density limit. The expressions are tested with the Soave-Redlich-Kwong equation of state. Results for vapor-liquid and gas-liquid systems are discussed. | A new density-dependent mixing rule for the SRK equation of state | 10.1007/BF00649091 |
1987-06-01 | Standard system for calibrating and checking level gauges for cryogenic media under working conditions | 10.1007/BF00866845 | |
1987-04-01 | Relations for determining the degree of perforation of the radiation screen as a function of the magnitude of gas evolution from the inner surfaces are obtained. | Effect of perforation of a radiation screen on preevacuation of extended cryogenic systems with high-vacuum thermal insulation | 10.1007/BF00872036 |
1987-04-01 | Laser differential spectrophotometer for the study of photochemical reactions at cryogenic temperatures | 10.1007/BF00660059 | |
1987-01-01 | This paper presents an overview on cryogenic structural materials. Material properties at liquid helium temperature are described for application in superconducting technology which requires highly reliable structural materials. The candidate materials are nonmagnetic high strength austenitic steels and titanium alloys of which the mechanical properties, i.e. strength, toughness, fatigue and creep are strongly affected by composition and microstructure. | Structural Materials for Cryogenic Use | 10.1007/978-94-009-3445-0_16 |
1987-01-01 | Increasing the service life of components of cryogenic machines | 10.1007/BF01150652 | |
1987-01-01 | Some spectroscopic and kinetic measurements of hemoproteins have been carried out in cryogenic temperatures in order to achieve a number of specific objectives such as trapping transient intermediates, retarding decay processes and electron/nuclear relaxation rates, controlling reaction rates, expanding a range of temperature, increasing signal-to-noise ratios of spectroscopic data, etc. It is generally assumed in these measurements that freezing would not adversely alter the sites and properties of interest. The absence of obvious changes in the frozen sample after thawing is sometimes taken as a proof that freezing has not irreversibly modified the protein. However, this does not exclude the possibility that a hemoprotein may be reversibly altered in frozen states due to the physical stress exerted by crystallized solvent water molecules. In addition, it is well known that pH and other physical properties of aqueous solutions could be significantly changed upon freezing^1. | Effects of Freezing on the Coordination State and Ligand Orientation in Hemoproteins | 10.1007/978-1-4613-1941-2_51 |
1987-01-01 | Tension and compression of glass reinforced and organic plastics at room and cryogenic temperatures | 10.1007/BF00815390 | |
1987-01-01 | The results of a research project on fatigue properties of high-manganese steels for cryogenic use under the sponsorship of Science and Technology Agency of Japan are summarized. The temperature dependence of cyclic deformation, low cycle fatigue life, notch sensitivity and near threshold fatigue crack growth rate are discussed. | Fatigue Behavior of High-manganese Steel at Cryogenic Temperature | 10.1007/978-94-009-3445-0_18 |
1987-01-01 | The irretrievable loss of the naturally occurring germplasm is a problem of great concern to tree breeders. Many countries are facing serious gene pool losses in populations of some valuable tree species (4). With increasing world demand for forest products and continuing deforestation, the conservation of genetic resources has become an urgent issue. The preservation of available germplasm for use in future tree improvement is imperative. | Cryopreservation of Woody Species | 10.1007/978-94-009-4484-8_16 |
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