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1987-01-01 | A transportable laser system for remote sensing of road traffic emissions (carbon monoxide) has been developed and field testet at different sites in the city of Frankfurt. Based on the DAS technique using lead-salt diode lasers, the system yields mean values of the species density across a measurement path of several hundred meters. Interference with other absorbing species as well as varying operating conditions are compensated by using the second derivative technique. The time for starting operation after transportation of the system was two hours, time of availability during the campaign was better than 90%. It appeared sufficient to have technical checks and readjustments only once per day. | A Transportable Laser System for Remote Sensing of Road Traffic Emissions | 10.1007/978-94-009-3991-2_4 |
1987-01-01 | We have started some time ago a research activity to evaluate the possible use of cryogenic detectors in the detection of very rare events [1]- First tests of silicon calorimeters have been performed at CERN and showed the feasibility of using such devices as photon detectors- Germanium, totally doped commercial thermometers have been also used as detectors for alpha particles [2], [3]. In collaboration with SGS, the main local semiconductor manufacture, we are currently developing a series of silicon cryogenic detectors which will be tested with low-energy photons emitted by a 55Fe X-ray source. | Considerations on Front End Electronics for Bolometric Detectors with Resistive Readout | 10.1007/978-3-642-72959-1_13 |
1987-01-01 | The x-ray crystal structure of the Rhodopseudomonas viridis reaction center - cytochrome c complex (RC-cyt complex) has stimulated considerable interest (1–4). One of the most remarkable features of the protein is the linear array of the four cytochrome c hemes which contrasts sharply with the arrangement suggested from functional studies for the analogous hemes of Chromatium vinosum . (5) How the four hemes, two high potential and two low potential, are structurally arranged around the bacteriochlorophyll dimer, (BChl)_2, contained in the reaction center is a question of long standing. This question is an important component of the deeper issue that addresses the mechanism of electron transfer not only from these hemes to the light generated (BChl) _2 ^+ but also between the hemes (see 1–3). Of particular interest in this regard is the finding that the low potential heme(s) of photosynthetic bacteria are able to undergo oxidation at cryogenic temperatures, while reactions of high potential hemes tend to ‘freeze out’ with decreasing temperature (see 1,3, and 6). | Construction and Characterization of Monolayer Films of the Reaction Center Cytochrome-C Protein From Rhodopseudomonas
Viridis
| 10.1007/978-1-4613-1941-2_83 |
1987-01-01 | Hundred years ago a fog of liquid hydrogen droplets was created by two dedicated scientists at the Cracow University in Poland. The scientists, Wroblewski and Olszewski least suspected that a century later their effort will help place man on the moon and fill automobile fuel tanks of the common man. In 1898, James Dewar in England obtained liquid hydrogen as a visible liquid body in test tube (instead of a mist) by using the vacuum insulated container invented by him. The technology of liquefying hydrogen has matured over the years and today it is used in thousands of tonnes in many parts of the world. | Cryogenic Storage of Hydrogen | 10.1007/978-94-009-3809-0_9 |
1987-01-01 | The desire to measure atmospheric emission spectra of the upper atmosphere has led to the development of cryogenically cooled infrared Fourier transform spectrometers. These spectrometers combine the sensitivity advantage of a Fourier transform spectrometer with the sensitivity gains obtainable with modern infrared detectors operated at low photon backgrounds. The temperature required to obtain maximum sensitivity is primarily determined by the wavelength region of interest, longer wavelengths requiring lower temperatures. In order to take full advantage of reduced background operation, the preamplifier must be cooled in order to reduce the noise. Low noise preamplifiers capable of operation down to liquid helium temperatures have been developed. Three cryogenically cooled spectrometers of significantly different design are discussed. The first instrument is a standard Michelson interferometer cooled to 10 K with supercritical helium and capable of 1 wave number resolution. This interferometer has been successfully flown on a rocket and obtained measurements of atmospheric limb emission at tangent altitudes from 70 km to 150 km. The second is a field widened prism interferometer which operates at liquid nitrogen temperature and has been flown on a rocket and obtained measurements of atmospheric emission in the 2 to 8 micrometer region during an aurora. The third is a balloon borne liquid nitrogen cooled interferometer which incorporates cat's eye retroreflectors for end mirrors and is capable of 0.1 wave number resolution. This spectrometer has successfully flown on a balloon several times and obtained measurements of atmospheric limb emission at tangent altitudes from 0 km to 30 km. | Cryogenic instrumentation and detector limits in FTS | 10.1007/BF01201695 |
1986-10-01 | The speed of ultrasound propagation is measured in neon-helium solutions. The effect of a helium impurity on ultrasound propagation speed in cryogenic liquids is analyzed. | Velocity of ultrasound propagation in solutions of helium in cryogenic liquids | 10.1007/BF00870846 |
1986-06-01 | When headspace gas chromatography utilizing capillary columns is used for trace analysis, sample enrichment is often needed. This involves splitless sample injection of fairly large gas volumes and relatively long sampling times. As a result of this, the band of the sample vapor may be too large causing peak distortion and poor resolution. This problem can be easily overcome by the use of cryogenic trapping. While this can be accomplished by cooling the whole column to subambient temperature during sample introduction, a more convenient way is to utilize part of the first coil of the capillary column as a cryogenic trap. The paper discusses the theoretical background and instrumentation of cryogenic trapping and demonstrates the possibilities through a number of examples. | Cryofocusing in the combination of gas chromatography with equilibrium headspace sampling | 10.1007/BF02311600 |
1986-05-01 | A convenient procedure has been described for enhancing the sensitivity of equilibrium headspace gas chromatography. The technique involves the cryogenic focusing of headspace vapors at the head of a 0.32 mm fusedsilica capillary column which has been coupled to a packed column injection port. Cryofocusing is accomplished automatically by cooling the GC oven and results in enhanced sensitivity with improved resolution. With this simple focusing technique no sample splitting is required which gives at least a 10-fold increase in sensitivity. A Multiple Headspace Injection (MHI) technique has been described which allows several rapid headspace injections to be made at the start of a single chromatographic run. Cryofocusing causes the injections to be superimposed, thus increasing the sensitivity even further. These procedures have been demonstrated for flavor and aroma analyses of toothpaste and soft drink samples. | Headspace analysis with cryogenic focusing: A procedure for increasing the sensitivity of automated capillary headspace analysis | 10.1007/BF02311877 |
1986-05-01 | Cryogenic sampler for collecting radioactive gases and aerosols | 10.1007/BF00865965 | |
1986-03-01 | Calculation of conditions of transition to characteristic flow regimes of two-phase cryogenic medium in tubes and annular channels | 10.1007/BF01149070 | |
1986-02-01 | Metrological support to means of measuring flow rate for liquid cryogenic media | 10.1007/BF00868832 | |
1986-01-01 | We tested two samples of a commercial shielding alloy at 300, 77, 4 and 1.91 Kelvin, using field strengths of 4 and 50 gauss rms and frequencies from 0.08 Hz to 10 KHz. Both samples were effective shields, even at 1.91 Kelvin. One of the samples, which had received a special treatment, shielded even more effectively at 4 Kelvin than at 300 Kelvin, particularly at higher frequencies. | Data on a Magnetic Shield Alloy at Low Magnetic Fields from 300 Kelvin to 1.91 Kelvin, and 0.08 Hz to 10kHz | 10.1007/978-1-4613-9871-4_55 |
1986-01-01 | Precise pressure measurement is an important requirement frequently encountered in cryogenic experimentation. Applications range from vapor pressure and gas thermometry to gas sample density measurements. Since a capacitance-type pressure sensing element can be constructed of non-magnetic, UHV-compatible materials to cover a wide range of pressure, be bakeable to 400°C, and be reliable and easy-to-operate, it is an ideal candidate for this task. Design and operational characteristics of this family of instruments with reference to low temperature applications will be reviewed. | Cryogenic Applications of Capacitance-Type Pressure Sensors | 10.1007/978-1-4613-2213-9_143 |
1986-01-01 | Liquid helium duct spacers in large superconducting magnets must have high compressive strength to withstand large electromagnetic forces. They must also show a low thermal contraction, in the direction perpendicular to the laminations, to maintain windings stability at liquid helium temperature. To attain higher glass content or higher density, we adopted glass roving cloth with mineral fillers and unidirectional woven glass cloths. E-,S-, and R-glass cloths were examined as reinforcements and epoxy and bismaleimide triazine, as matrix resins. The thermal contraction of GFRP with unidirectional woven cloths (cross ply) was nearly equal to that of stainless steel; compressive strength at cryogenic temperature was nearly 1200–1300 MPa. GFRP with glass roving cloths and fillers also showed low thermal contraction, however, their compressive strength was nearly 800–900 MPa. | Mechanical Properties of Low Thermal Contraction GFRP | 10.1007/978-1-4899-2010-2_21 |
1986-01-01 | The design of the 4.5 K primary cooling system and higher temperature shield cooling systems for the SSC are described. Typical flow diagrams for the magnet piping systems are presented. Estimated heat loads are given. The systems have been designed to accomodate the great distances, 90 km and up, over which the load will be distributed. Provision has been made for cooldown, warmup, quench recovery and magnet replacement, as well as for steady-state operation. | The SSC Cryogenic System | 10.1007/978-1-4613-2213-9_6 |
1986-01-01 | Recent developments in welding technology are reviewed. Mechanical properties of recently developed alloys and welds produced by various processes are tabulated. | Welding Advances in Cryogenics | 10.1007/978-1-4613-9871-4_9 |
1986-01-01 | Passive orbital disconnect struts can potentially reduce the support conductance a factor of 10 over state-of-the-art tension band nondisconnect supports and cut helium dewar weights in half for the same lifetime. A series of thermal and structural tests were performed to verify that this performance improvement is real. Structural tests on a PODS-III support system (consisting of six struts) is reported here. The results show the predicted performance improvements can be achieved and the PODS-III supports are ready for flight applications. For large tankage systems requiring higher side load capability, a PODS-IV version is currently being developed. | System Structural Test Results: Six Pods III Supports | 10.1007/978-1-4613-2213-9_105 |
1986-01-01 | The cryogenic deformation behavior under uniaxial tensile stress was investigated for 32Mn-7Cr high manganese steel using a diametral extensometer. The tensile deformation and serration behavior were observed for varying gage diameters and strain rates (< 5 × 10^-4s^-1). A significant effect of gage diameter and strain rate on strengths and total elongation was not seen at 4 K. As the gage diameter became smaller or the strain rate lower, the strain to initiate serration decreased. The geometrical changes in the specimen during serrated yielding are also discussed in relation to the internal specimen heating. | Effects of Gage Diameter and Strain Rate on Tensile Deformation Behavior of 32Mn-7Cr Steel at 4 K | 10.1007/978-1-4613-9871-4_37 |
1986-01-01 | Measurement means for variable-field induction under cryogenic conditions and their metrological support | 10.1007/BF00862482 | |
1986-01-01 | Because of their inflammable contents LNG storage facilities are considered as installations with a very high risk potential. Safety and reliability issues have therefore been extensively discussed (see [1], [2], [3]). | Collection and Usage of Reliability Data for Risk Analysis of LNG Storage Tanks | 10.1007/978-3-642-82773-0_44 |
1986-01-01 | The effects of Hot Isostatic Pressing (HIP) on the superconducting properties of (Nb, Ti)_3Sn multifilamentary wires were studied. The (Nb, Ti)_3Sn wires, having a bronze (Cu-13wt%Sn-0.3wt%Ti) to niobium ratio of 2.8, were manufactured by the conventional bronze method using the hot hydrostatic extrusion. After the diffusion heat treatment, the (Nb, Ti)_3Sn wires were HIP treated in a high pressure argon gas atmosphere of 130 MPa in a temperature range from 600 to 750°C. The critical current measured in the transverse magnetic field of up to 23 tesla indicates that the optimum temperature of HIP treatment on (Nb, Ti)_3Sn was less than 600°C. | Effects of Hot Isostatic Pressing on the Superconducting Properties of (Nb, Ti)_3Sn Multifilamentary Wires | 10.1007/978-1-4613-9871-4_116 |
1986-01-01 | For practical high-T_c Josephson devices like Nb_3Ge dc-SQUIDs, a multilayer technology is indispensable. A consequence is that interconnections between different layers are needed. This requires high-T_c superconducting contacts from one Nb_3Ge layer to the other. We therefore developed a versatile Nb_3Ge multilayer technology based on SiO_2 as insulating material. Bottom- as well as top Nb_3Ge layers have a T_c of nearly 21 K. Interconnections between two Nb_3Ge films have T_c’s up to 20.5 K. As a first application for this described multilayer technology, a Nb_3Ge dc-SQUID of the microbridge type with integrated input coil was prepared. The whole device is working up to 19 K. | A Multilayer Technology with High T_c Nb_3Ge Films | 10.1007/978-1-4613-9871-4_64 |
1986-01-01 | We performed a experiment to detect a temperature rise at cryogenic temperature using a dual-core optical fiber. This fiber has two single-mode optical cores in one fiber. We demonstrated that a temperature rise of 4 K was detectable at 4.2 K. The sensitivity of this method can be improved using a longer fiber. This method may be applicable as a quench detector for superconducting magnets. A quench detector using this optical method is immune from electromagnetic noise, free from troubles caused by break-down of electrical insulator, and has many advantages over a conventional quench detector measuring voltages of a magnet. | Detection of temperature Rise at 4.2 k by Using a Dual-Core Optical Fiber - An Optical Method to Detect a Quench of a Superconducting Magnet. | 10.1007/978-1-4613-2213-9_142 |
1986-01-01 | The object of this study is to acquire data on radiation damage of organic insulator films at low temperature. The specimens used were thin films of polyphenylene sulfide (PPS), polyarylether etherketone (PEEK), polyethylene terephthalate (PET), and polypyromellitimide (PPMI, Kapton H). Experiments were mainly done with PPS, since at the present there is little information on the cryogenic properties and radiation effects for this material. Irradiation of the films was performed at 20 K in the low-temperature irradiation facility of the Kyoto University Reactor and the mechanical properties of the films were measured at 77 K. In tensile tests of PPS films, both the unirradiated and irradiated specimens showed a gradual increase in strength beyond the elastic limit at all test temperatures. The tensile strength and the ultimate elongation of PPS films were almost independent of irradiation dose up to 8 MGy at 20 K. For comparison, similar mechanical tests were carried out with irradiated films of PEEK, PET, and PPMI. As far as the present experiments are concerned, the radiation tolerance of PPS films has been proved to be on the same level as that of PEEK and PPMI films. | Effect of Cryogenic Irradiation on the Mechanical Properties of Organic Insulator Films | 10.1007/978-1-4613-9871-4_19 |
1986-01-01 | Measurements of the coupling losses have been made on the several types of cables by changing the cable twist pitch and direction systematically in order to optimize the cable structures. A cable twist opposite in direction to the strand twist led to higher losses than those with identical twist directions. The twist pitch dependence of the losses could be interpreted on the basis of Campbell’s theory. The results indicate that the losses may be reduced by optimizing the cable twist pitch. The influences of the volume fraction of superconductors in the cable and the arrangement have also been examined. | Coupling Losses in Superconducting Cables | 10.1007/978-1-4613-9871-4_90 |
1986-01-01 | Metallurgical linking of the filaments and their proximity coupling through the normal metal matrix in in situ prepared superconducting composites cause greater ac losses than those observed for bronze process materials. Twisting of in situ wire, provided twist length is sufficiently small, results in a limitation of screening supercurrent density by the critical supercurrent density across the filament direction before the twisting. Supercurrent density across the filament direction is determined by both cross-linking and proximity coupling of filaments. Proximity supercurrents between the filaments can be greatly reduced by a high enough magnetic field, so that the separate contribution of metallurgical links can be determined. In fact, this is done by comparison of the magnetization hysteretic curves for the wires before and after twisting. Experimental results are presented for in situ composites with a superconductor concentration above the percolation threshold. Magnetization of the sample due to proximity coupling currents was nearly twice that due to the currents through metallurgical links. Reduction of the proximity currents in in situ composites can reduce ac losses by several times. | AC Losses for in Situ Superconducting Microcomposites | 10.1007/978-1-4613-9871-4_94 |
1986-01-01 | The porous plug is a proven method for phase separation in superfluid helium dewars operating in zero gravity. The principal operating regimes have been identified in laboratory experiments on porous plugs. In this paper a description of porous plug operation is given, and a new explanation is presented for the observed transition in the m vs. ΔP characteristic. Theoretical results are in qualitative agreement with experimental data. | The Liquid-Vapor Transition in Porous Plug Operation | 10.1007/978-1-4613-2213-9_96 |
1986-01-01 | For the structural materials used for fusion reactors, high strength and superior toughness are required at liquid helium temperature in heavy plate (over 100 mm thick). Both Mn-Cr and Ni-Cr austenitic steels are candidate materials for the next Fusion Reactor Project at JAERI (Japan Atomic Energy Research Institute), which has specifications of yield strength and K_IC fracture toughness of over 1200 MPa and 200 MPa $$\sqrt m $$ , respectively. This paper systematically examines the effect of metallurgical variables and thermomechanical processing parameters on strength and toughness obtained at 4.2 K for both types of stainless steels. Strength obtained at 4.2 K is influenced principally by chemical composition and austenitic grain size. Carbon and nitrogen exert a much greater influence on strength than substitutional elements in both Mn-Cr and Ni-Cr stainless steels. The value of Ky, expressing the grain size dependence of yield strength in the Hall-Petch relation, is 50 MPa $$\sqrt mm $$ for both steels. Toughness evaluated by Charpy impact energy and the K_IC value at 4.2 K is controlled by strength, Ni content, cleanliness of the steel, and austenitic grain size. The increase of Ni content and a reduction of S content improve both values markedly while maintaining high strength. For an optimization of the relationship between strength and toughness, austenitic grain refinement through thermomechanical processing is the most important process in heavy plate production. Candidate materials satisfying JAERI specifications have been determined for both types of stainless steels; their chemical compositions are 0.02C-22Mn-13Cr-7.5Ni-0.22N and 0.01C-1.5Mn-18Cr-12Ni-3.5Mo-0.21N. | Effect of Metallurgical Variables on Strength and Toughness of Mn-Cr and Ni-Cr Stainless Steels at 4.2 K | 10.1007/978-1-4613-9871-4_6 |
1986-01-01 | The internal tin process has been established as a cost effective and reliable method for the manufacture of practical high current density Nb_3Sn superconductor.^1–3 This paper describes fabrication and test results to date for internal tin process conductor elements that are being developed for the Lawrence Livermore National Laboratory for fusion applications at 18 Tesla and beyond. The filaments of the conductors are niobium or alloyed niobium reacted in a bronze matrix formed from copper and tin or doped tin elements. Ti, Mg and Ta are among the alloying elements being explored. Critical current measurements, and scanning electron microscope results are presented for variously reacted conductor elements. | Internal Tin Process Nb_3Sn Superconductors for 18 Tesla | 10.1007/978-1-4613-9871-4_119 |
1986-01-01 | A design is presented for a dipole magnet suitable for the proposed SSC facility. Test results are given for model magnets of this design 1 m long and 4.5 m long. Flattened wedge-shaped cables (“keystoned”) are used in a graded, two-layer “cos θ” configuration with three wedges to provide sufficient field uniformity and mechanical rigidity. Stainless steel collars 15 mm in radial depth, fastened with rectangular keys, provide structural support, and there is a “cold” iron flux return. The outer-layer cable has 30 strands of 0.648 mm diameter NbTi multifilamentary wire with Cu/S.C. = 1.8, and the inner has 23 strands of 0.808 mm diameter wire with Cu/S.C. = 1.3. Performance data is given including training behavior, winding stresses, collar deformation, and field uniformity. | A 6.4 Tesla Dipole Magnet For the SSC | 10.1007/978-1-4613-2213-9_3 |
1986-01-01 | Over the past twenty years separation processes based upon pressure swing adsorption have replaced cryogenic processes in a number of selected applications such as air separation for production of moderate quantities of nitrogen and oxygen and recovery of hydrogen from refinery and chemical plant gases. Key events contributing to the emergence of PSA as an important process option have been the development of synthetic zeolite molecular sieves by Union Carbide Corporation in the USA and of carbon molecular sieves by Bergbau-Forschung in Germany. Today PSA processes enjoy significant commercial use producing oxygen from 0. 1 Nm^3/h for medical application to 1500 Nm^3/h for steel mill use, for making nitrogen up to 1000 Nm^3/h for inerting and in purifying hydrogen streams of up to 100,000 Nm^3/h for refinery use. In this paper some of the principles of adsorptive separations are reviewed. The history of the technology is traced briefly with emphasis on key material, process and application events. The major commercial processes in the application of adsorption to bulk separation of air and hydrogen purification are reviewed in more detail with comparisons made to cryogenic alternatives in terms of specific characteristics, advantages and disadvantages where appropriate. Information on performance, reliability and comparative economics are discussed where available. | Gas Separation by Pressure Swing Adsorption | 10.1007/978-1-4613-2213-9_120 |
1986-01-01 | Creep behavior of Type 304 LN plate and 316 L shielded-metal-arc (SMA) deposited stainless weld metal was investigated at 4 K. Testing was performed at constant load in a creep machine with a cryostat designed for stability. Both transient and steady-state creep were observed during tests lasting over 200 h. Steady-state creep rates were much greater than expected from extrapolations of 300 K creep data. Creep rates on the order of 10^-10 s^-1 were observed at stresses around the yield stress for both materials. The stress exponent under these conditions is ~2.3. Possible creep mechanisms at this temperature and the impact of these results on the design of engineering structures for long-term structural stability at cryogenic temperatures are discussed. | Creep of 304 LN and 316 L Stainless Steels at Cryogenic Temperatures | 10.1007/978-1-4613-9871-4_44 |
1986-01-01 | Heat leak measurements of superconducting magnet suspension systems, and multi-layer insulation (MLI) systems are important for the optimum design of magnet cryostats. For this purpose, a versatile cryogenic test facility was developed having a functional end in which test components of differing geometrical configurations could be installed and evaluated. This paper details the test facility design and operating parameters. Experimental results of heat leak measurements to 4.5 K obtained on a post type support system having heat intercepts at 10 K and 80 K are presented. Included are measurements obtained while operating the 10 K intercept at temperatures above 10 K, i.e., in the 10–40 K range. Also reported is a description of the test facility conversion for a heat load study of several MLI systems with variations of MLI installation technique. The results of the first MLI system tested are presented. | Heat Leak Measurement Facility | 10.1007/978-1-4613-2213-9_145 |
1986-01-01 | Prior work on internal tin wire has shown that an increase in critical current results when the Nb_3Sn reaction temperatures (650–730°C) are preceded by low temperature diffusion heat treatments that distribute the tin. These heat treatments produce a more uniform tin distribution through the niobium filament array before substantial Nb_3Sn formation has occurred. Heat treatments as long as 19 days have been proposed as the optimal heat treatment for the conductor. However, it is possible to substantially reduce the low temperature heat treatment time while retaining the same high critical current. The success of shortened heat treatments may be interpreted on the basis of the Cu-Sn reaction, diffusion kinetics and the Nb_3Sn growth kinetics. | The Relationship between Critical Current and Microstructure of Internal Tin Wire | 10.1007/978-1-4613-9871-4_105 |
1986-01-01 | A subcritical liquid hydrogen orbital storage and transfer experiment is being designed for flight in the shuttle cargo bay. The Cryogenic Fluid Management Facility (CFMF) includes a liquid hydrogen storage tank supported in a vacuum jacket by two fiberglass epoxy composite trunnion mounts. The capability of the CFMF to meet a seven mission requirement is extremely sensitive to the fatigue life of the composite trunnions at cryogenic temperatures. An E-glass/S-glass epoxy composite material was selected for the trunnions since it provided desirable strength, weight and thermal characteristics. Because of the limited extent of analytical or experimental treatment of the fatigue life of this composite at cryogenic temperature, an experimental program was conducted to provide verification of the trunnion design and performance capability at ambient and liquid hydrogen temperatures. Basic material fatigue property data were obtained for the laminate of interest using specifically prepared test specimens. Full-scale trunnions were manufactured and subjected to cyclic load testing to verify fatigue life. An analytical evaluation of the thermal performance of the trunnions was conducted, and a test setup is being manufactured to correlate analytical predictions with test results. | LH_2 On-Orbit Storage Tank Support Trunnion Design and Verification | 10.1007/978-1-4613-9871-4_30 |
1986-01-01 | Superconducting NbN films have been deposited onto unheated substrates using a dual ion-beam technique. The NbN films produced have T_c up to 12 K and resistivities of ≳150µΩ-cm. The substrate temperature does not exceed 100 °C. TEM analysis of these films shows a random in-plane orientation of <100 Å-size grains. Electron diffraction indicates fine-grain polycrystalline material, and a Read x-ray camera verifies this to be the high-T_c δ-phase with the B1 crystal structure. Using a native oxide barrier on these films and a Pb_.71Bi_.29 counterelectrode, tunnel junctions are produced with current densities of 30 A/cm^2 and V_m of 50 mV at 4.2 K. Artificial barriers have been successfully produced, using oxidized Al or Ta overlayers or AlN. The quality of the resulting I-V curves is comparable to that of junctions with native oxide barriers. The junction resistance with the artificial barriers is higher, however, and the conductance at large voltages reflects the different properties of the artificial barriers. | Dual Ion-Beam Deposition of Superconducting NbN Films | 10.1007/978-1-4613-9871-4_75 |
1986-01-01 | A superconducting proton storage ring will be installed in a 6336 m long ring tunnel as part of a 30 GeV electrons, 820 GeV protons colliding beam facility at DESY (Hamburg). The magnets will be cooled by three refrigerators installed in a central cryogenic building. Each unit has a capacity of both 6775 W refrigeration and 20.5 g/s current lead cooling gas rate at 4.4 K, as well as 20 000 W between 40 and 80 K for the cooling of radiation shields. Coolant will be supercritical helium at 2.5 × 10^5 Pa, T ∼ 4.4 K being continuously recooled by two-phase helium boiling at 1.1 × 10^5 Pa within the dipoles. A large transfer line going all around the tunnel will supply individual sections. Sufficient redundancy for the most sensitive components ensures continuous operation in case of individual component failures. The whole system will be automated by means of a process control computer system. | The Refrigeration System for the Superconducting Proton Ring of the Electron Proton Collider HERA | 10.1007/978-1-4613-2213-9_72 |
1986-01-01 | The low level signals from cryogenic sensors and transducers are usually carried to the electronic signal conditioning and data handling systems at ambient temperatures by long electrical leads running from the cryogenic environment to ambient. There are many applications, outside those using superconducting devices, in which there are advantages to be gained by placing part or all of the electronic system in the cryogenic environment adjacent to the measuring point. This paper discusses the requirements for an ideal cold electronic instrumentation system and then reviews the present state of the art in relation to off-the-shelf electronic components, devices and integrated circuits, and the published literature. The integration of sensors/transducers with cold electronics is discussed and areas for development are outlined. | Cryogenic Instrumentation with Cold Electronics — a Review | 10.1007/978-1-4613-2213-9_135 |
1986-01-01 | The 3 m Φ × 5 m long × 1.5 T superconducting solenoid for the Fermi- lab Collider Detector has been installed at Fermilab and was tested in early 1985 with a dedicated refrigeration system. The refrigerator and 5.6−Mg magnet cold mass were cooled to 5 K in 210 hours. After testing at low currents, the magnet was charged to the design current of 5 kA in 5−MJ steps. During a 390 A/min charge a spontaneous quench occurred at 4.5 kA due to insufficient liquid helium flow. Three other quenches occurred during “slow” discharges which were nevertheless fast enough to cause high eddy current heating in the outer support cylinder. Quench behavior is well understood and the magnet is now quite reliable. | Testing of the Superconducting Solenoid for the Fermilab Collider Detector | 10.1007/978-1-4613-2213-9_20 |
1986-01-01 | Special transfer lines were required to transport supercritical hydrogen gas at 20 K and 1.5 MPa and liquid methane at 800 K and 0.4 MPa over a distance of about 18 m, to moderator vessels sited within a concrete shielded area. The moderator vessels (1 L and 1/2 L volume respectively) are built into shielding material surrounding the uranium target which produces high energy pulsed neutrons. Energies up to 400 W can be deposited in the cryogenic fluid, which the control system must be capable of handling within less than one minute. The flow rates were designed to be 500 cm^3/sec for hydrogen and 220 cms^3/sec for methane. In order to maintain biological shielding integrity the lines had to be as compact in cross section as possible, and replacable using remote handling techniques. As commonly used plastic materials could not be used for spacers etc, on account of their poor radiation resistance, new techniques had to be developed to meet the long term requirements of the lines. | Special Transfer Lines for the Spallation Neutron Source | 10.1007/978-1-4613-2213-9_114 |
1986-01-01 | This paper will include an in-depth discussion of the design, fabrication, and operation of the Mirror Fusion Test Facility (MFTF) cryogenic system located at Lawrence Livermore National Laboratory (LLNL). Each subsystem will be discussed to present a basic composite of the entire facility. | Cryogenic Systems for the Mirror Fusion Test Facility | 10.1007/978-1-4613-2213-9_67 |
1986-01-01 | The temperature dependence of the cohesion parameter “a” (=Ω_aRT_C ^2 /P_c) of the van der Waals equation of state has been established for predicting vapor-liquid equilibrium (VLE) values for hydrogen-containing systems at cryogenic conditions. Instead of using one temperature function for Ω_a of hydrogen and another for other components as suggested by Graboski and Daubert, a single temperature function for Ω_a was developed for components of cryogenic interests including hydrogen. The optimal Ω_a values of hydrogen above its critical temperature were determined from VLE values of binary hydrogen - n-alkane systems without using the conventional binary adjustable parameter k_ij, and correlated. The success of the proposed correlation was demonstrated by predicting the VLE values for hydrogen-containing systems, including four binaries with the second component other than a n-alkane, and two ternaries. The van der Waals equation used in the calculation is the simplest cubic equation of state. For the systems considered, the agreement obtained between the calculated and the experimental K values from the proposed correlation is about the same or even better than those obtained from the method of Graboski and Daubert. | Prediction of VLE Values for Systems Containing Hydrogen Using the Van Der Waals Equation | 10.1007/978-1-4613-2213-9_131 |
1986-01-01 | A design has been developed for an SSC 6T option dipole magnet cryostat. The design criteria that defines the basic parameters and performance requirements are discussed. Details of the single phase assembly, suspension, insulation, thermal shields, vacuum vessels and interconnections are presented. Results of the experimental program in support of the design effort are discussed. | The Cryostat for the SSC 6 T Magnet Option | 10.1007/978-1-4613-2213-9_7 |
1986-01-01 | Sam Collins was a perfect gentleman in the traditional sense. He worked without fanfare and had no time for image building. He wanted his work to speak for itself and his papers were modest descriptions of his major accomplishments. Many of his original ideas were never published; nevertheless they have served as the basis for the achievements of others. | A Tribute to Samuel C. Collins: September 28, 1898 – June 19, 1984 | 10.1007/978-1-4613-2213-9_1 |
1986-01-01 | Photoacoustic spectroscopy provides a method for measuring optical and thermal properties of materials in a variety of physical forms. Measurement of the sample response to modulated radiation can employ pressure transducers, sensitive temperature probes, laser beam deflection, surface displacement, and piezoelectric detectors. This range of detectors permits samples to be studied in liquid, gaseous, or high vacuum environments over a wide range of temperatures. This paper reviews the generation of a PAS signal and the experimental configurations used for various modes of signal detection. Attention is paid to the special features associated with low temperature measurements and the relatively sparse literature extant in this area is briefly discussed. | The Characterization of Cryogenic Materials by Photoacoustic Spectroscopy | 10.1007/978-1-4613-9871-4_56 |
1986-01-01 | X-ray absorption techniques have in recent years been developed into powerful probes of the electronic and structural properties of materials difficult to study by other techniques. In particular, the extended x-ray absorption fine structure (EXAFS) technique can be applied to a variety of cryogenic materials. Three examples will be used to demonstrate the power of the technique. The first is the determination of the lattice location of dilute alloying additions such as Ta and Zr in Nb_3Sn. The Ta additions are shown to reside predominately in Nb lattice sites, while Zr is not uniquely located at either Nb or Sn sites. In addition to structural information, temperature dependent EXAFS studies can be used to determine the rms deviations of atomic bond lengths, providing information about the temperature dependence of interatomic force constants. For Nb_3Sn deviations are found from simple harmonic behavior at low temperatures which indicate a softening of the Nb-Sn bond strength. The final example is the study of interfacial properties in thin film systems. This is accomplished by making x-ray absorption measurements under conditions of total external reflection of the incident x-rays. As some examples will show this technique has great potential for studying interfacial reactions, a process used in the fabrication of many superconducting materials. | The Characterization of Cryogenic Materials by X-Ray Absorption Methods | 10.1007/978-1-4613-9871-4_57 |
1986-01-01 | The Space Infrared Telescope Facility (SIRTF) is a superfluid helium cooled 85 cm telescope with three infrared instruments at the focal plane. SIRTF will establish in space a long term maintainable infrared observatory for the region of 2–700 μm. The cryogenic system can be designed to last up to six years with 1280 kg of superfluid, and can function in either a 28.5° or 98° inclination orbit by exchanging the sunshade. The lifetime is primarily a function of instrument heat load rather than parasitic heat to the cryogen system. | Study of an All SFHE SIRTF Cryogenic System | 10.1007/978-1-4613-2213-9_99 |
1986-01-01 | The science and technology of producing a low-temperature environment is generally referred to as cryogenics. The word cryogenics has its origin in the Greek language where “cryos” means frost or cold and “gen” is a common root for the English verb to generate. Strictly speaking, cryogenics means to produce cold, yet the term has developed a more general connotation over years of usage by engineers and scientists. Today, the word cryogenics is associated with the production and study of low-temperature environments. Thus, a cryogenic engineer is a person who specializes in these areas. The expertise of a cryogenic engineer can vary considerably within this discipline. For example, he or she may be concerned mostly with heat transfer aspects of low-temperature fluids or alternatively, improved methods of producing low temperatures. Expertise in cryogenic engineering is in demand in a wide variety of technical fields including advanced energy production and storage technologies, transportation and space programs, and a wide variety of physics and engineering research efforts. | Cryogenic Principles and Applications | 10.1007/978-1-4899-0499-7_1 |
1985-10-01 | The vertical distribution of the CH_3Cl mixing ratio in the stratosphere has been measured from samples collected during two balloon flights on the 21 October 1982 and 10 September 1983. Measurements were made with two analytical techniques that were also employed for previous analyses of stratospheric samples: gas chromatography (GC) and a gas chromatograph/mass spectrometer (GC/MS) combination. The results from all balloon flights performed to date are combined to derive an average experimental profile of CH_3Cl at midlatitudes. The profile shows that the CH_3Cl mixing ratio decreases by about one order of magnitude between 20 and 30 km altitude. A comparison of the new observations with model profiles reveals discrepancies in the lower stratosphere that amount to a factor of about 3. Possible causes for these discrepancies are discussed. | A study of the vertical distribution of methyl chloride (CH_3Cl) in the midlatitude stratosphere | 10.1007/BF00122524 |
1985-09-01 | A method is described for the reliable recovery of hybridoma cell lines from cryogenic storage. This procedure provides for (a) the efficient retrieval of cells secreting antibody for rapid confirmation of specific antibody production; (b) cells for cloning; (c) cells for restocking the liquid nitrogen storage banks; and (d) cultures to detect and possibly eliminate contamination. | A reliable method for recovering cryopreserved hybridoma cells for cloning | 10.1007/BF01665926 |
1985-09-01 | Low temperature mechanical behavior of microalloyed and controlled-rolled Fe-Mn-Al-C-X alloys | 10.1007/BF02663026 | |
1985-07-01 | A machine for thermal fatigue testing of materials in the nonuniform thermally stressed condition with cooling to cryogenic temperatures | 10.1007/BF01528484 | |
1985-06-01 | Study of gas emission from the internal chambers of cryogenic equipment | 10.1007/BF01147933 | |
1985-06-01 | We combined visual stimulation of the corticogeniculate pathway with cryogenic blockade of area 17 to examine the visual spatial structure of the cortical influence on single macaque LGN cells. Excitatory central areas surrounded by inhibitory regions and vice versa were found with equal frequency. Unstructured influences were also seen. The structure of the influence suggests that modulation of the spatial parameter may be an important function for the corticogeniculate pathway. | Evidence for spatial structure in the cortical input to the monkey lateral geniculate nucleus | 10.1007/BF00237664 |
1985-05-01 | Study of high-pressure cryogenic pumps with different methods of delivery control | 10.1007/BF01147562 | |
1985-05-01 | Resistance to deformation of structural steels exposed to current pulses and cryogenic temperatures | 10.1007/BF01524200 | |
1985-03-01 | Thermokinetic concept in determining the long-term strength of cryogenic steels by means of the microhardness method | 10.1007/BF01755930 | |
1985-01-01 | Two-circuit cryogenic system for cooling and cryostating a superconductive turbogenerator | 10.1007/BF01148292 | |
1985-01-01 | The first all-superconducting sampler, with a rise time of 26 ps, was reported by Faris in 1980 [ 1 ]. Recently, an improved version was developed by Wolf et al. with a 2.1 ps response [ 2 ]. In this approach, a Faris puiser [ 1 ] is used to superimpose a fast current spike on an unknown waveform. This sum signal is then applied to a sense junction, whose dc bias is adjusted to reach the switching threshold. By sweeping the fast pulse in time, the unknown signal can be replicated. The speed of these systems was limited by the response time of the superconducting Josephson junctions, although junctions with switching speeds on the order of one picosecond are possible. | Development of a Picosecond Cryo-Sampler Using Electro-Optic Techniques | 10.1007/978-3-642-70780-3_50 |
1985-01-01 | Vertical profiles of the stratospheric CCl_4, CH_3C1, CH_3CC1, C_2F_2C1_3 mixing ratios derived from two balloon flights over Southern France (44° N) in 1982 and 1983 are presented. A total of 26 air samples were collected in situ by a newly developed balloon-borne cryogenic sampler. The samples were analysed in the laboratory within four weeks after the flight employing two different analytical techniques: gas chromatography and a gas chromatograph/mass spectrometer combination. The observed mixing ratios are well in the range of previous determinations of these species in the stratosphere. Above about 30 km CC1_4 and CH_3CC1_3 mixing ratios are below the analytical detection limits of both techniques. A comparison with 1-D model calculations shows that for all species the observations are lower than the theoretical profiles. | Vertical Profiles of Chlorinated Source Gases in the Midlatitude Stratosphere | 10.1007/978-94-009-5313-0_24 |
1985-01-01 | Plant cell cultures are potential sources for the production of specific secondary compounds. These cultures are commonly maintained by continuous subculture, which includes the disadvantages of high costs, requirement of shaking capacity, risk of contamination and, above all, the possible loss of biosynthetic capacity in long-term culture (Zenk 1978). Consequently, a culture with particular yield characteristics may not be readily available if serial passage is the only means of preservation. Among the attempts to eliminate these problems freeze preservation seems to be the most successful method in the case of cell suspensions. Until now little work has been carried out with callus cultures. The progress in this area has been reviewed recently by Withers (1980, 1982) and Henshaw et al. (1980). | Cryopreservation of Plant Cell Cultures | 10.1007/978-3-642-70717-9_31 |
1985-01-01 | The CRESU technique uses uniform supersonic jets as flow reactors and allows the determination of ion-molecule reaction rate coefficients at extremely low temperatures (down to 8 K). This technique requires an exceptional pumping capacity and a correct design of contoured axisymmetric Laval nozzles. Several reactions have been studied in oxygen or nitrogen buffer gases (O_2 ^+ + CH _4 ; O_2 ^+ + 20_2 ; N_2 ^+ + 2N_2) as well as in helium buffer gas (He^+ + N_2, O_2, CO ; N ^++ H_2, CH_4, CO, O_2 ; N_2 ^+ + N_2 + He; N_2 ^+ + O_2 ; O^+ + O_2), some of which being relevant to interstellar cloud chemistry. | Measurements Of Ion-Molecule Reaction Rate Coefficients Between 8 and 160 K by the Cresu Technique | 10.1007/978-94-009-5432-8_31 |
1985-01-01 | Experimental research conducted at the University of California at Berkeley indicated that plain and prestressed/reinforced lightweight concrete behaved favorably under both static and cyclic loading conditions at cryogenic temperatures. This research indicated: (1) that the mechanical properties of lightweight concrete are significantly affected by moisture content, but not significantly by relatively high-intensity cyclic fatigue, (2) that one-way prestressed concrete specimens subjected to cyclic axial tension and compression as well as cryogenic thermal shock exhibited only minor degradation, and (3) that two-way prestressed concrete specimens subjected to cyclic membrane shear and also to cryogenic thermal shock exhibited only minor surface cracking and reductions in flexural stiffness. These results indicate that prestressed/reinforced high-strength lightweight concrete exhibits excellent cryogenic properties, and may qualify as a material for use as a secondary barrier for offshore liquefied gas containment vessels. | Static and Cyclic Behavior of Structural Lightweight Concrete at Cryogenic Temperatures | 10.1007/978-4-431-68284-4_47 |
1985-01-01 | During cryogenic collection of stratospheric air samples the presence of large amounts of ozone may initiate contaminating or sample altering processes, either directly in the gas phase or on surfaces. To investigate the possibility of sample alteration, a laboratory experiment was performed under simulated stratospheric conditions. After thorough preflight preparation the sampler was filled with test gas aliquots, containing compounds of interest in the range of several pptv. Amounts of ozone were added to ten out of fifteen samples. After warming, the samples were analysed for CH_4, N_2O, CO, CO_2; C_2H_6, C_3H_8, C_2H_2, and for CFC1_3, CF_2C1_2, C_2F_3C1_3, CC1_4, CH_3C1, CHC1_3, CH_3CC1_3 and their long-term stability studied over a period of four weeks. CH_4, N_2O, CO_2, CFC1_3, and CF_2C1_2 measurements do not depend on ozone concentration while amounts of C_2H_6, C_2H_2, C_3H_8, and CHC1_3 varying from 50 % to 100 % may be affected in the presence of ozone. Affects on the other chlorinated hydrocarbons are less than 50 % with the exception of CC1_4, which slowly decomposes even in the absence of ozone. If analysed within four weeks after sampling, the profiles derived for these compounds will represent their actual stratospheric distribution to better than a factor of two. | A Laboratory Test of Cryogenic Sampling of Longlived Trace Gases Under Simulated Stratospheric Conditions | 10.1007/978-94-009-5313-0_25 |
1985-01-01 | A cryocooler is a device used to produce refrigeration at very low temperatures in the cryogenic range, 0 to 120 K. | Free-Piston Stirling Cryocoolers | 10.1007/978-3-642-82526-2_9 |
1984-10-01 | Effect of medium temperature on the characteristics of closed cryogenic systems | 10.1007/BF01679105 | |
1984-10-01 | Results of a theoretical and experimental investigation are presented for liquid-vapor compositions during the boiling of binary cryogenic mixtures. Factors affecting the degree of phase nonequilibrium are set down. | Degree of nonequilibrium of the vapor and liquid phases during the boiling of binary cryogenic mixtures | 10.1007/BF00869910 |
1984-08-01 | A new dual-polarized cryogenic Schottky barrier mixer receiver for radio astronomy applications is described. Between 85 and 120 GHz, the double sideband receiver temperature, including all contributions from the polarization diplexing system, telescope coupling optics and dewar window is less than 125°K in either channel. Novel features include a very broadband, fixed tuned mixer design and a compact, low-loss, linear polarization diplexing scheme. | A very low-noise receiver for 80–120 GHz | 10.1007/BF01010018 |
1984-07-01 | New evaporators of cryogenic systems for storage and gasification | 10.1007/BF01246683 | |
1984-07-01 | New series of high-pressure pumps for cryogenic liquids | 10.1007/BF01246687 | |
1984-07-01 | Main trends in the investigation of processes in liquid cryogenic systems | 10.1007/BF01246682 | |
1984-06-01 | Life of parts of 12Kh18N10T steel at cryogenic temperatures | 10.1007/BF01320293 | |
1984-05-01 | An optical system for measuring the deformations of a flat sample in a cryogenic chamber | 10.1007/BF01529062 | |
1984-04-01 | A method is proposed for evaluating the boundary between quasistatic and dynamic regimes of vapor bubble growth and separation. The pressure boundary is evaluated on the basis of data on the boiling of cryogenic liquids and water. | Boundary of transition from quasistatic to dynamic regime of vapor bubble growth and separation | 10.1007/BF00826393 |
1984-03-01 | A hypothesis on heterogeneous nucleation in a liquid volume is used as a basis for obtaining a relation to close a system of equations which describes non equilibrium discharge. | Heterogeneous nucleation mechanism in the flow of a superheated cryogenic liquid | 10.1007/BF00831364 |
1984-02-01 | Recently we have described a new mode of IR detection which utilizes charge storage in localized levels of an extrinsic semiconductor at low temperatures. This method is based on field-assisted impurity photoionization. IR photoionization depletes the population of stored charge in localized impurity states. The integration takes place inside the bulk of the semiconductor. A large negative going pulse causes rapid field ionization of the remaining charge after an IR exposure. Readout is accomplished by measuring this ejected charge. Using a cryogenically cooled monochromator, we have studied the spectral response and its field dependence. Extremely low dark currents (<3×10^−18 A) permit IR integration times of up to 12 hours or more. For the first time, significant photoresponse is obtained from a cryogenic Si:P detector at wavelengths up to 43 μm, well beyond the nominal long wavelength cutoff of 27 μm. | IR detection by depletion of trapped charge in localized impurity states of an extrinsic semiconductor | 10.1007/BF01417650 |
1984-01-01 | The first Cryogenic Engineering Conference was held at the National Bureau of Standards (NBS), Boulder, Colorado, in 1954. Timmerhaus^1 has given the early history of the NBS Cryogenic Laboratory and the Cryogenic Engineering Conference and has acknowledged the many contributions of Russell B. Scott of NBS to the early development of the Conference, The subsequent history of the Conference has been marked by the waxing and waning of several fields of cryogenic activity, for example, the AEC hydrogen program, the NASA space vehicle development program, and the LNG storage, transfer, and metrology work. These peaks and valleys are, however, superposed upon a generally increasing background of activity in refrigeration systems, cryogenic fluid and material properties, heat transfer, and applied superconductivity. At the present time the conference is characterized by many papers on superconducting applications, refrigeration systems for 1.8 – 5 K, and space science and technology. | The Cryogenic Engineering Conference: 1954–1984 | 10.1007/978-1-4613-9865-3_1 |
1984-01-01 | The separation of synthesis gas consisting of various concentrations of hydrogen and carbon monoxide from methane and other light hydrocarbons is a major step in the manufacture of SNG from coal. Since the separation(s) must be conducted at cryogenic temperatures, it is energy intensive. Information leading to improved efficiencies in synthesis gas/hydrocarbon separation is highly desirable. Thus, this laboratory has conducted phase and volumetric studies of gas mixtures comprised of the principal components in methane/synthesis gas mixtures. To date, extensive vapor-liquid equilibrium data (200 experimental points) have been reported^1. A second, complementary study of the volumetric properties is underway and whose current findings are discussed herein. | Measurement and Correlation of Isochoric P-V-T Behavior of a Binary H_2-Ch_4 Mixture from Near Ambient to Cryogenic Temperatures and Pressures to 700 ATM | 10.1007/978-1-4613-9865-3_105 |
1984-01-01 | To insure that Brookhaven’s superconducting accelerator magnets are reliable and their field quality meets accelerator requirements, each magnet is pre-tested at operating conditions after construction. MAGCOOL, the production magnet test facility, was designed to perform these tests, having the capacity to test ten magnets per five day week. This paper describes the control aspects of MAGCOOL and the advantages afforded the designers by the implementation of a commercial process control computer system. | Automation of a Cryogenic Facility by Commercial Process Control Computer | 10.1007/978-1-4613-9865-3_48 |
1984-01-01 | Geist and Lashmet^1 in 1959 discussed design criteria for miniature open cycle Joule-Thomson refrigerators and developed an early working model. Subsequently, several other models have been developed^2 and their utilization appears to be widespread. Despite deficiencies such as low efficiency and the requirement of a high-pressure gas source, J-T minicryocoolers have the advantages of compactness, low cost, and the ability to achieve low temperatures very quickly. Accordingly, they have attracted much attention. | A Fast Cool-Down J-T Minicryocooler | 10.1007/978-1-4613-9865-3_71 |
1984-01-01 | Excellent magnetic shielding performance at 4.2 K is required for the superconducting quantum interference devices to avoid influences of electromagnetic noises. This could be provided by a ferromagnetic shield using high permeability material. For cryogenic uses, a quaternary alloy of Ni-Fe-Mo-Cu has already been proposed.^l | Magnetic Properties and Ferromagnetic Shielding of Ni-Fe-Mo Alloys at Cryogenic Temperatures | 10.1007/978-1-4613-9868-4_54 |
1984-01-01 | Different kinds of thermal transducers which use the thermal disturbance anemometry principle have been tested at our Institute in order to evaluate their performances as flowmeters for use in liquid helium. | Characterization of Anemometric-Type Flowmeters for Cryogenic Helium | 10.1007/978-1-4613-9865-3_101 |
1984-01-01 | Methods of optimizing location of boil-off gas cooled support and insulation heat intercepts to minimize heat leak to helium dewars are discussed. Analyses include use of separate gas streams for support and insulation cooling and the much simpler case of one stream for both purposes. Calculations are made for stainless steel and epoxy-fiberglass supports with ratios α = (A_IL_S)/(A_SL_I), ranging from 25 × 10^3 to 800 × 10^3. Heat intercept locations are optimized for one through six intercepts. Calculations include independent location of intercepts on the supports and insulation and the effect of positioning the intercepts with equal length/thickness fractions. Results are presented graphically for easy use by dewar designers. | Discrete Cooling of Supports and Multi-Layer Insulation in Helium Dewars | 10.1007/978-1-4613-9865-3_89 |
1984-01-01 | This paper reports measurements of the pressure and temperature differences as a function of heat flux over the length of glass microbore tubing containing He II. At low heat fluxes the fluid shows a laminar flow behavior distinguished by linear relations in temperature and pressure gradients with heat flux. High heat fluxes cause the flow to become turbulent. In the turbulent region the relations are non-linear. | Heat Flow in He II in Microbore Channels | 10.1007/978-1-4613-9865-3_39 |
1984-01-01 | Superconductors, materials which can carry large electrical currents without significant electrical losses, will soon live up to their name not only in static magnetic environments but in most time varying magnetic environments also. In the past, high ac losses in superconductors have limited their use to relatively low frequency ac applications. However during the past decade, considerable progress in superconductor fabrication has resulted in filament size reduction from 800 µ m to 1 µ m leading to ac loss reductions of between two and three orders of magnitude. | Advanced Applications of Superconductors | 10.1007/978-1-4613-9865-3_15 |
1984-01-01 | An airborne system needs 120 standard cubic meters of helium to operate. The physical constraints of the system allow a volume of only 0.26 m^3 for the helium storage and supply system. This requires the helium to be stored cryogenically at 20.69 MPa and 10 K. A compact lightweight inexpensive heating system is required to heat the helium from 10 K to 250 K in a very short time period. The system consists of a stainless steel shell and tube heat exchanger (HEX) and a solid propellant gas generator (GG). The propellant used has a flame temperature of 2828 K which minimizes the system size. The temperature extremes and unique gas generator application create unknowns in the analysis and design of the heat exchanger and the high temperature requires a method to cool the hot gas to allow the heat exchanger to be manufactured from stainless steel. The method devised recirculates a portion of the heat exchanger exhaust gas to cool the primary gas generator stream to 1367 K. | Heating Cryogenic Helium with a Solid Propellant Gas Generator | 10.1007/978-1-4613-9865-3_86 |
1984-01-01 | Austenitic Fe-Cr-Ni steels are widely used as construction materials in cryogenic systems subjected to high loads and repeated “cooling-heating” cycles. These alloys have low stacking fault energy (SFE) values. During temperature lowering the SFE decreases sharply, and in some cases this may lead to changes in dislocation structure and phase state when cooling and heating. | Effect of the Structure of Fe-Cr-Ni Alloys Strained at Low Temperatures on Their Electrical Resistivity | 10.1007/978-1-4613-9868-4_57 |
1984-01-01 | The structural material used in construction of superconducting magnets requires high proof stress, toughness, and nonmagneti.sm at cryogenic temperatures. High-nitrogen-containing austenitic stainless steel is a candidate for this purpose, and manganese-containing stainless steels, such as 21–6–9, are considered to be the most promising materials, though some problems remain concerning their fracture toughness. | Nitrogen-Containing 25Cr-13Ni Stainless Steel as a Cryogenic Structural Material | 10.1007/978-1-4613-9868-4_17 |
1984-01-01 | The solubility of water in cryogenic liquids, such as liquid nitrogen (LIN), liquid oxygen (LOX) and liquid methane, would be expected to be extremely low and undetectable according to normal theories of solution^1, 2. Following indications by unstable surface evaporation phenomena, recent work at Southampton University using gravimetric methods suggested that the solubility of water in liquid nitrogen may be as high as 10 ppm or 10^-5 mole fraction^3. This figure is many orders of magnitude greater than that expected which is 10^–16 to 10^-18 mole fraction^3, 4. In this paper, experiments using Fourier transform, infra-red absorption sepctroscopy are described which confirm the extraordinary solubility of water in liquid nitrogen, oxygen and methane, and eliminate the possibility of experimental artifacts by making parallel observations on solutions of heavy water D_2O in liquid nitrogen. This discovery has a bearing on many handling and storage situations in the cryogenic engineering industry and in low temperature laboratories. | The High Solubility of Water in Liquid Nitrogen and Other Cryogenic Liquids | 10.1007/978-1-4613-9865-3_113 |
1984-01-01 | Commercial helium refrigeration/liquefaction systems are based on the same throttling Joule-Thomson expansion process used by Linde to liquefy air in 1895^1: the expansion of a precooled high pressure gas to form liquid at the low pressure. The unusually low triple point of helium precludes the simple counterflow heat exchange method of precooling the gas. Claude and later Collins contributed to the development of efficient liquefiers by adding work producing expanders as the precooling for Linde’s basic cycle. This allows the flexibility of choosing the temperature levels (or mass cross-flow), as well as the heat exchange AT, to optimize the cycle performance. | An Optimum Cold end Configuration for Helium Liquefaction Cycles | 10.1007/978-1-4613-9865-3_55 |
1984-01-01 | Industrial applications of cryogens motivates the need to develop stress analysis techniques suitable for these conditions. Non-contacting optical techniques are attractive as they are unaffected by thermal expansion, magnetic fields or the hostile environment of the cryogen. This paper extends holographic-moiré and Young’s fringe techniques to measure displacements (mixed mode) in the vicinity of a crack in a glass-composite submerged in liquid nitrogen. The authors are unaware of prior use of these techniques under cryogenic conditions. | Photomechanical Stress Analysis Under Cryogenic Environments | 10.1007/978-1-4613-9868-4_14 |
1984-01-01 | In recent years there has been increasing interest in raising refrigeration efficiency and capacity in cycles which produce cooling below 4.2 K. It is, of course, desirable to be able to produce the required subatmospheric pressure efficiently in the system. | Combined Cold Compressor/Ejector Helium Refrigerator Cycle | 10.1007/978-1-4613-9865-3_56 |
1984-01-01 | Composite materials can be given almost mechanical characteristics by choosing suitable components and manufacturing process. This advantage, however, is also a disadvantage in practical applications; that is, composite materials show large scatter in mechanical behavior from material to material, and hence it is difficult to generalize about a specific material. Even in one material, complicated and various fracture processes, which are characteristic of composite materials, cause scatter of data. | Acoustic Emission from Composite Materials at Low Temperatures | 10.1007/978-1-4613-9868-4_4 |
1984-01-01 | Woven-fabric composites are used in superconducting magnets and to contain of cryogenic liquids. These materials provide thermal and electrical insulation and can be subjected to large mechanical and thermal loads. Previous studies^1,2 on woven-fabric composites predicted internal stresses for mechanical loads at room temperature. Here, the thermal-mechanical response of a plain-weave laminated composite at cryogenic temperatures was studied by predicting the load-deformation response of the fundamental “unit cell” (Fig. 1). Stiffness and stresses within the unit cell were calculated by a finite-element model for idealized thermal-mechanical load conditions prior to fracture. | Stiffness and Internal Stresses of Woven-Fabric Composites at Low Temperatures | 10.1007/978-1-4613-9868-4_1 |
1984-01-01 | The Heavy Ion Spectrometer System (HISS) relies upon superconducting coils of cryostable design to provide a particle bending field of 3 tesla. A previous paper described^1 the cryogenic facility including helium refrigeration and gas management. This paper discusses a control strategy which has allowed full time unattended operation and significant^a operating cost reductions. Liquid nitrogen consumption at the magnet has been reduced 65% by using the sensible heat available in the nitrogen exhaust gas. Operating the heat intercept on the coil supports at temperatures above 80K increases the heat load on the 4K system — this particular system required an additional 10% compressor power input to compensate. The result is a net savings on the overall operating cost. Electrical costs have been reduced^b by negotiating off peak interruptible power. Frequent manual transfers between power transformers have been trouble free. 10,000 operating hours have been logged to date. | Control and Operation Cost Optimization of the Hiss Cryogenic System | 10.1007/978-1-4613-9865-3_40 |
1984-01-01 | Natural Gas Technology | 10.1007/978-94-009-5634-6_9 | |
1984-01-01 | Unexpected and sometimes hazardous variations in evaporation rate (boil-off) appear to be a feature of the storage behaviour of cryogenic liquids. For the purpose of this paper “cryogenic liquids” include all liquids boiling at temperatures below ambient, i.e. LPG, LNG, LIN, LOX, LH_2, LHe etc. | Thermal Overfill, and the Surface Vaporisation of Cryogenic Liquids under Storage Conditions | 10.1007/978-1-4613-9865-3_90 |
1984-01-01 | Cryogenics is widely used in the life sciences in today’s world. In China, biomedical applications of cryogenics have grown to become an important branch of science and a series of encouraging results has been produced.^1–3 Cryogenic techniques deserve emphasis as excellent alternatives for certain problems which are especially difficult to manage by other methods. The future is promising and activities are on going in diverse institutions, laboratories and hospitals belonging to universities, industries and the Chinese Medical Academy of Sciences. The national conference on cryo-biomedicine is held in China each year, and it draws several hundred technical reports. Biomedical applications of cryogenics in China cover a wide range of activities which are summed up here for brief discussion as follows: 1) Cryotherapy and cryoequipment for cancers and tumors, 2) artificial insemination employing cryogenics, 3) cryoprotection and cryopreserva-tion, 4) cryobiology, 5) study of heat transfer in living tissue and organs at cryogenic temperature, and 6) therapeutic effects of high magnetic field and studies of the magnetic field of the human body. | Biomedical Applications of Cryogenics in China | 10.1007/978-1-4613-9865-3_115 |
1984-01-01 | An important structural component of the Westinghouse Large Coil Program (LCP) superconducting magnet is the JBK-75 (modified A-286) stainless steel conductor sheath. This sheath is basically a welded pipe that encloses a bundle of superconducting cables. The JBK-75 conductor sheath also acts as a containment vessel for liquid helium. Stresses and strains produced on the conductor sheath result from a combination of magnetic loading, internal pressures and thermal loads. | Cryogenic Fatigue Crack Growth Rate Properties of JBK-75 Base and Autogenous Gas Tungsten Arc Weld Metal | 10.1007/978-1-4613-9868-4_41 |
1984-01-01 | As is widely known, in 1971 an accident occurred at the LNG terminal in La Spezia^1, Italy, in which a sharp increase in the quantity of boil off gas was observed in a storage tank. This phenomenon was called rollover and several analytical methods for predicting rollover time and peak boil off gas rate were proposed. In this paper, we describe our experimental studies of rollover, as well as the simulated results from these studies. | Rollover Test in LNG Storage Tank and Simulation Model | 10.1007/978-1-4613-9865-3_91 |
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