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2007-06-01
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The influence of cryogenic treatment on the mechanical properties of the extruded Mg-Gd-Y-Zr(Mn) alloys was investigated by the tensile tests, scanning electron microscopy(SEM), transmission electron microscopy(TEM), and energy dispersive X-ray spectroscopy (EDS). The results show that the mechanical properties of both alloys are improved greatly during the in situ tensile test by soaking the samples in liquid nitrogen for 10 min. The ultimate tensile strength, yield tensile strength and elongation of cryogenic treated magnesium alloy added with zirconium or manganese are largely elevated. And remarkable microstructure change is observed in both alloys by cryogenic treatment. There are a large number of twins, rod-like, tree-like and chrysanthemum-like precipitated phases in the microstructures and the fracture surfaces exhibit the characteristics of ductile rupture when they are observed at room temperature.
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Effects of cryogenic treatment on mechanical properties of extruded Mg-Gd-Y-Zr(Mn) alloys
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10.1007/s11771-007-0060-x
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2007-05-01
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The paper addresses the main problems associated with the fabrication of cryogenic fuel targets and their delivery to the irradiation zone of an inertial confinement fusion (ICF) facility. Optimal solutions of these problems have been developed at the Lebedev Physical Institute for the case of free-standing direct-irradiation cryogenic targets. In contrast to the traditional technology, the approach proposed and demonstrated is shown to conform to all requirements of the current ICF program: (a) quality of fuel layering, (b) stability of layering, and (c) minimization of tritium inventory. This technology is the basis for a designed device of introducing cryogenic targets into the chamber of an ISKRA-6 high-power laser facility being developed in Russia.
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Cryogenic fuel targets for inertial fusion: Optimization of fabrication and delivery conditions
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10.1007/s10946-007-0011-x
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2007-04-01
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Polycrystalline pellets of the rare earth sesquioxide Dy_2O_3 were irradiated at two temperatures (∼120 K and ∼300 K) with 300 keV Kr^++ ions up to a fluence of 1 × 10^20 Kr/m^2. The crystal structure of the irradiated Dy_2O_3 was observed to change from an ordered cubic bixbyite structure (so-called C-type rare earth sesquioxide structure) to a disordered, anion-deficient fluorite structure. A relatively low ion dose (∼2.5 displacements per atom [dpa]) was sufficient to induce a complete order-to-disorder (O-D) phase transformation at cryogenic temperature (∼120 K) irradiation, while at room temperature (∼300 K) a higher dose (∼25 dpa) produced only a partial O-D phase transformation.
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Irradiation-induced order-to-disorder phase transformation at different temperatures in Dy_2O_3
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10.1007/s11837-007-0052-1
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2007-04-01
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This paper describes a study on the effects of cryogenic treatment of tungsten carbide. Cryogenic treatment has been acknowledged by some as a means of extending the tool life of many cutting tool materials, but little is known about the mechanism behind it. Thus far, the only few detailed studies conducted pertain to the cryogenic treatment of tool steels. However, tungsten carbide cutting tools are now in common use in industry. This paper primarily reports and analyses the differences in tool performance between cryogenically treated and untreated tungsten carbide tool inserts during the high-speed milling of medium carbon steel. In addition to dry cutting, machining with coolant was also tested. From the results, it can be seen that cryogenically treated tools exhibit better tool wear resistance than untreated ones. Also, it is evident that the application of coolant during cutting helps to reduce tool wear experienced by the cryogenically treated tools even further. In addition, cryogenically treated tools are found to perform best under a particular set of cutting conditions.
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Performance of cryogenically treated tungsten carbide tools in milling operations
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10.1007/s00170-005-0379-0
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2007-04-01
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Ba(Zn_1/3Ta_2/3)O_3 has been prepared with different dopants that gave best microwave dielectric properties at room temperature. Effects of different dopants on the low temperature microwave dielectric properties of BZT were investigated. With decrease in temperature, loss tangent was found to decrease marginally and then increase at temperatures lower than 100 K. Increase in loss factor at lower temperatures were found to be less for dopants with smaller ionic radii. Dielectric constant was found to be almost independent of temperature. Temperature coefficient of resonant frequency slowly decreased from a positive value to negative value when temperature was lowered. Temperature at which τ_f becomes zero was found to vary for different dopants. There is a temperature stable region for tanδ, ɛ_r and τ_f which varies for different dopants.
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Effect of dopants on the low temperature microwave dielectric properties of Ba(Zn_1/3Ta_2/3)O_3 ceramics
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10.1007/s10854-006-9051-1
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2007-04-01
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Small-hole drilling in several materials using abrasive fluidjets—abrasive-waterjets and abrasive cryogenic jets with liquefied nitrogen as the working fluid—were investigated through laboratory tests, numerical simulation, and phenomenological analysis. Drilling is accomplished by an abrasive slurry for abrasive-waterjets and primarily by a stream of dry abrasives for abrasive cryogenic jets as the liquefied nitrogen changes phase after exiting the mixing tube. Scaling factors were successfully derived through analysis of profiles digitized from hole images to collapse the data. For abrasive-waterjets, water is nearly incompressible; a high stagnation pressure inside the blind hole was developed causing delamination in laminates and cracking in the thermal barrier coating. The return abrasive slurry also possesses considerable residue erosion power that could cause damage to the hole entrance due to secondary wear. Neither delamination in laminates nor cracking in the thermal barrier coating is however observed when abrasive cryogenic jets were used.
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Hole drilling with abrasive fluidjets
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10.1007/s00170-005-0398-x
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2007-03-01
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Photosynthetic reaction centers (RCs) from Rhodobacter sphaeroides capture solar energy by electron transfer from primary donor D to quinone acceptor Q_B through the active A branch of electron acceptors. The light-induced electron paramagnetic resonance (EPR) spectrum from native RCs that had Fe^2+ replaced by Zn^2+ was investigated at cryogenic temperature (80 K, 35 GHz). In addition to the light-induced signal due to the formation of D^+.Q _A ^−. observed previously, a small fraction (ca. 5%) of the signal displayed very different characteristics. The signal was absent in RCs in which the Q_B was displaced by the inhibitor stigmatellin. Its decay time (τ=6 s) was the same as observed for D^+.Q _B ^−. in mutant RCs lacking Q_A, which is significantly slower than for D^+.Q _A ^−. (τ=30 ms). Its EPR spectrum was identical to that of D^+.Q _B ^−. . The quantum efficiency for forming the major component of the signal was the same as that found for mutant RCs lacking Q_A (ϕ=0.2%) and was temperature independent. These results are explained by direct photochemical reduction of Q_B via B branch electron transfer in a small fraction of native RCs.
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Light-induced EPR spectra of reaction centers fromRhodobacter sphaeroides at 80 K: Evidence for reduction of Q_B by B branch electron transfer in native reaction centers
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10.1007/BF03166246
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2007-03-01
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We present our results on developing a diagnostic complex for high-precision characterization of the parameters of laser-fusion microobjects, such as microspheres and cryogenic targets (the microobject size is 1–2 mm). The complex operates based on the principle of tomography. The complex consists of (a) the scanning system providing a set of shadow projections of a microobject in the visible range of radiation and (b) specially developed software for 3D reconstruction of the microobject from the set of projections. The spatial resolution of the optical system is 1 µm for a probing-radiation wavelength of 490 nm. The distinctive features of the diagnostic complex are (1) operation with both free-standing and mounted targets and (2) the possibility of scanning the targets from room to cryogenic temperatures. The operation of the complex was demonstrated in the reconstruction of polystyrene microspheres by a large set (80–90) of shadow projections at room and cryogenic temperatures.
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Creation of a diagnostic complex for the characterization of cryogenic laser-fusion targets using the tomography method with probing irradiation in the visible spectrum
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10.1007/s10946-007-0010-y
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2007-03-01
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The energetic characteristics of the compression and burning of targets with beryllium and beryllium deuteride shells are compared. The characteristics considered include the hydrodynamic efficiency, the efficiency of energy transmission to the thermonuclear fuel, and the gain factor found from numerical simulation using the ‘Diana’ one-dimensional mathematical code. The calculations are carried out for direct-drive cryogenic laser targets with the ablator shells made of beryllium or beryllium deuteride with parameters corresponding to the third harmonic of energy of the neodymium-laser radiation with a pulse energy of 1–3 MJ. It is proved that the gain of beryllium hydride targets can be brought to the level of beryllium targets due to variations in the geometrical parameters of BeD_2 targets. It is shown that the fission of BeD_2 or BeDT ablators in reactor-scale targets could significantly contribute to the final thermonuclear yield.
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Energetic efficiency of laser thermonuclear targets with ablator shells made of beryllium materials: A comparative analysis
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10.1007/s10946-007-0009-4
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2007-03-01
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An efficiency extraction of fluoroquinolones in chicken muscle was achieved by pulverizing it in a freezer mill before treatment with NaOH (10mM)/MeCN (1:1). The improvement of cryogenic grinding in the extraction was demonstrated for the same piece (whole leg) of four chickens treated with enrofloxacin in equal doses. A confirmatory method based on high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) was used to analyze the extracts. The chromatographic separation was achieved in 5min with a Synergi Fusion-RP 80A (50 x 2mm, 4μm) column filled with a hybrid polymer. The HPLC was coupled with a detector based in a quadrupole–linear ion trap Q-TRAP that allows a confirmatory detection according to the European legislation. The specificity of the method was assessed by testing a number of representative blank muscle samples ( n = 10) to verify the absence of potential interfering compounds. The limits of detection and quantitation were 2 and 5ng g^1 of quinolones in muscle samples, respectively. The chromatographic method was demonstrated to be linear for the range studied (5–500ng g^1) with the P value for lack-of-fit in the ANOVA table greater or equal to 0.10 (calibration coefficient 0.9998 and 0.9996 for ciprofloxacin and enrofloxacin, respectively). The mean intra-day relative standard deviation (RSD) ( n = 6, c = 50ng g^1) was 6%; inter-day assay gave a RSD of 12%. The extraction and clean-up were carried out in one step with very satisfactory recovery data (between 65 and 101%).
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Cryogenic grinding pre-treatment improves extraction efficiency of fluoroquinolones for HPLC-MS/MS determination in animal tissue
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10.1007/s00216-006-1090-1
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2007-02-01
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Stone cells (sclereids) in Norway spruce ( Picea abies ) bark have been reported to be highly lignified tissues that are important in physical defence against bark beetle invasion. Microchemical analyses of the low-molecular weight compounds in the stone cells of Norway spruce were carried out using laser microdissection in combination with cryogenic nuclear magnetic resonance and mass spectrometry (LMD/NMR/MS). Two phenolic compounds, the stilbene astringin and the dihydroflavonol dihydroxyquercetin 3′- O -β- d -glucopyranoside, were identified indicating that stone cells are more than just repositories for lignin. Both of these compounds were also found to be present in other phloem tissue at a higher level than in the stone cells based on quantification by cryogenic ^1H NMR. Our results suggest that stone cells may be involved in chemical as well as physical defense against bark beetles and their associated microorganisms. This paper reports on the identification of secondary plant metabolites from a single laser-microdissected population of plant cells offering a sensitive new way to determine the chemical profile of specific plant cell types with a high degree of precision.
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Microchemical analysis of laser-microdissected stone cells of Norway spruce by cryogenic nuclear magnetic resonance spectroscopy
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10.1007/s00425-006-0376-z
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2007-01-01
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It is commonly known that cryogenic data, technology, and information are applied across many military, National Aeronautics and Space Administration (NASA), and civilian product lines. Before 1950, however, there was no centralized US source of cryogenic technology data. The Cryogenic Data Center of the National Bureau of Standards (NBS) maintained a database of cryogenic technical documents that served the national need well from the mid 1950s to the early 1980s. The database, maintained on a mainframe computer, was a highly specific bibliography of cryogenic literature and thermophysical properties that covered over 100 years of data. In 1983, however, the Cryogenic Data Center was discontinued when NBS’s mission and scope were redefined. In 1998, NASA contracted with the Chemical Propulsion Information Agency (CPIA) and Technology Applications, Inc. (TAI) to reconstitute and update Cryogenic Data Center information and establish a self-sufficient entity to provide technical services for the cryogenic community. The Cryogenic Information Center (CIC) provided this service until 2004, when it was discontinued due to a lack of market interest. The CIC technical assets were distributed to NASA Marshall Space Flight Center and the National Institute of Standards and Technology. Plans are under way in 2006 for CPIA to launch an e-commerce cryogenic website to offer bibliography data with capability to download cryogenic documents.
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Sources of Cryogenic Data and Information
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10.1007/0-387-46896-X_2
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2007-01-01
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Calculation of cost of liquefied natural gas (LNG) produced and realized on the basis of a cryogenic plant built by Kriogenmash OAO is scrutinized. The share of the electric power cost in the LNG production cost and the transportation cost for LNG supply to the consumer is determined, taking account of the specific nature of agricultural operations. An LNG gasification unit is examined.
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Energy generation in agriculture based on introduction of liquefied natural gas complexes
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10.1007/s10556-007-0005-0
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2007-01-01
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Cryogenic temperatures are critical to allow infrared, gamma-ray and X-ray detectors to operate with low background noise and high sensitivity. As a result, the world’s aerospace industry has long dreamed of having the means for multiyear cryogenic cooling in space to enable long-life sensors of various forms for scientific, missile defense, and reconnaissance observations. Not long after the first Sputnik was launched into space in October 1957, engineers and scientists were actively seeking means of providing cryogenic cooling for evermore sophisticated and sensitive detectors in a variety of spectral regions. Although both passive cryoradiators and stored cryogens have provided a source of cryogenic cooling for many missions, the consistent dream of scientists and mission planners was always for a mechanical refrigerator that could achieve the temperatures of the coldest cryogens (vastly colder than possible with passive radiators) and have multiyear life without the finite life limitations of stored cryogens. The first cryocoolers in space were short-life Joule–Thomson and Stirling cryocoolers flown on both US and USSR missions around 1970. Since that time, extensive research and development of evermore sophisticated cryocoolers (Stirling, Vuilleumier, Brayton, magnetic, sorption, and pulse tube) has taken place in the world’s aerospace industry. This chapter examines the enormous progress made by the aerospace industry over the past 50 years in developing both cryostats and cryocoolers to enable the widespread use of cryogenic temperatures in space.
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Aerospace Coolers: A 50-Year Quest for Long-Life Cryogenic Cooling in Space
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10.1007/0-387-46896-X_11
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2007-01-01
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Three different treatments, including heat treatment, deep cryogenic treatment and laser surface melting, were carried out on 30Cr_2Ni_4MoV rotor steel. Electrochemical polarization curve and stress corrosion test at high temperature autoclave were applied to evaluate the corrosion resistance of treated specimens in high temperature water. Results indicate that conventional heat treated specimens with a lower yield strength will increase the value of K _IH, and thus reduce the stress corrosion cracking susceptivity. However, no apparent improvement was obtained on the hardness and corrosion resistance due to the limited carbon precipitate and austenite transformation after the deep cryogenic treatment of 30Cr_2Ni_4MoV rotor steel. In comparison, the best corrosion resistance of laser treated specimens was gained among the three-method-treated specimens by using the electrochemical polarization tests at temperature of 90°C. Nevertheless, some micro-cracks produced on the tensioned surface during the fabrication of self-loaded U bend specimen, and thus lead to a decreased stress corrosion cracking resistance in the environment of high temperature water.
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Comparison of 30Cr_2Ni_4MoV Rotor Steel with Different Treatments on Corrosion Resistance in High Temperature Water
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10.1007/978-3-540-76694-0_189
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2007-01-01
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Fluorescence imaging of cells and tissue can be used to evaluate β-NADH redox and location. At low temperature, β-NADH fluorescence intensity increases and therefore sensitivity of imaging increases. In this paper, the temperature dependence of fluorescence was evaluated for β-NADH in glycerol/water solution and in trehalose/sucrose glass. The average fluorescence lifetime for NADH in glycerol/water is 0.66 ns, compared with 5.3 ns in trehalose/ sucrose at 20°C. Emission spectra were recorded from 290 to 12 K. The fluorescence of β-NADH in glycerol/water increases ∼16 fold and the emission shifts about 35 nm to the blue as temperature decreases. Much smaller change is seen for fluorescence of β-NADH in sugar glass. Below 77 K, the β-NADH spectral features did not change significantly with temperature change, and so no increase in sensitivity is obtained by going to very low temperatures. It is suggested that the sensitivity of β-NADH fluorescence is related to water relaxation around the excited state molecule. Differences in water in various tissues may contribute to β-NADH fluorescence changes when cells are altered.
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Temperature Dependence for Fluorescence of β-NADH in Glycerol/Water Solution and in Trehalose/Sucrose Glass
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10.1007/s10895-006-0146-0
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2007-01-01
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The fabrication of multifilamentary Nb_3Sn wireswas started by the discovery of the bronze process, a solid-state diffusion process, to form filamentary A15 structure compounds in 1969–1970. Through a number of improvements and modifications of the original process in the ensuing years, these wires are nowindispensable components for the construction of magnets, producing very high magnetic fields for nuclear magnetic resonance spectroscopy, magnetic fusion experiments, and future high-energy particle accelerators. A comprehensive review article summarizes the state of the knowledge up to 1980 on the formation mechanisms and the superconducting properties of the A15 compounds that were fabricated by this process. Since 1980, significant advances have been made in the basic understanding of the factors controlling the growth processes, and basic superconducting properties of the bronze-processed Nb_3Sn. In particular, significant progress has been made in understanding the effects of alloying on these properties and mechanisms for fluxline pinning in the compound. Furthermore, for the practical usage of these wires, tremendous progress in the critical-current densities of multifilamentary Nb_3Sn wires has been made over the last several years. This chapter reviews these new findings about Nb_3Sn by the solid-state diffusion process and the critical-current densities of the state-of-the-art multifilamentary Nb_3Sn wires.
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Understanding Properties and Fabrication Processes of Superconducting Nb_3Sn Wires
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10.1007/0-387-46896-X_12
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2007-01-01
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Stored fast ion beams in atomic and molecular collision experiments are discussed with an emphasis on electron-ion interactions at low relative energies. Recent progress was obtained in electron collision spectroscopy using an electron-cooled stored ion beam and a separate electron target in the same storage ring; from a cryogenic photocathode, electron beams with internal temperatures of 5 to 10 K were produced. Results are presented for dielectronic recombination resonances, resolving the hyperfine structure of stored lithiumlike scandium ions and obtaining precise results for the fine structure splitting of these ions, and for ro-vibrational resonances in the recombination of electrons with hydrogen molecular ions, revealing sharp structures down to 2 meV. An overview of the cryogenic storage ring (CSR) project in Heidelberg is given.
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Progress in stored ion beam experiments on atomic and molecular processes
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10.1007/978-3-540-73466-6_15
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2007-01-01
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Since 1954, the extraordinary growth in the use and application of cryogenic liquids has followed very significant improvements in cryogenic insulation. Today, for example, hold-times of 1000 days for liquid helium and liquid hydrogen systems can easily be achieved, in comparison with hold-times measured in hours some 50 years ago. These improvements have also been applicable to the low-loss transport and handling of liquid air gases for an ever-widening range of industrial uses.
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Development of Low-Loss Storage of Cryogenic Liquids over the Past 50 Years
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10.1007/0-387-46896-X_7
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2007-01-01
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Environmental concerns are causing commonly used chlorofluorocarbon (CFC) refrigerants to be phased out of production. The less ozone-depleting HCFC’s are regulating. The green house effecting HFC’s are also likely to be regulated and banned in the next period. Accordingly, attention is drawn to the Stirling refrigerator, which is a perfect a freon free refrigerator. Moreover, The Stirling cycle has the highest theoretical cycle efficiency corresponding to the value of the Carnot cycle among the proposed thermodynamic cycles. The green house effect by carbon dioxide issue would make better recognizing the importance of efficient use of energy in terms of high energy conservation measures. The authors have designed and developed a 100 W class Stirling refrigerator for household use. And the prototype machine has been integrated with a 100 litter class refrigerator. The operating characteristics of this Stirling unit or the prototype machine have been evaluated. Moreover, the authors evaluated the machine driving engine mode using ultra-low temperature. As a result, the operational characteristics of the Stirling cycle machine have been clarified with respect to design factors. These results demonstrate that the Stirling cycle machine is one of the promising candidates as a new refrigeration system or a new generation system.
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Experimental Study on a Stirling Cycle Machine of 100W Design Capacity
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10.1007/978-3-540-76694-0_95
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2007-01-01
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In the 50th year of the Cryogenic Engineering Conference, the present review covers the development of cryogenic processes for oxygen, nitrogen, liquid hydrogen, and liquefied natural gas over that past period. It is confined to those processes of commercial interest, as applied to large-scale production. In all three sectors included in the present review, very significant advances have been made as the result of market forces. The developments that have contributed to the improvement in efficiency, scale of application, and economics are described.
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Fifty-Years’ Development of Cryogenic Liquefaction Processes
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10.1007/0-387-46896-X_8
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2007-01-01
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This review provides a survey of major advances that have occurred in recent years in the area of helium cryogenics. Helium-temperature cryogenics is the enabling technology for a substantial and growing number of low-temperature systems from superconducting magnets to space-based experimental facilities. In recent years there have been many advances in the technology of low-temperature helium, driven mostly by new applications. However, to keep the review from being too broad, this presentation focuses mainly on three of the most significant advances. These are: (1) the development of large-scale recuperative refrigeration systems mainly for superconducting magnet applications in accelerators and other research facilities; (2) the use of stored superfluid helium (He II) as a coolant for spacebased astrophysics experiments; and (3) the application of regenerative cryocoolers operating at liquid helium temperatures primarily for cooling superconducting devices. In each case, the reader should observe that critical technologies were developed to facilitate these applications. In addition to these three primary advances, other significant helium cryogenic technologies are briefly reviewed at the end of this chapter, along with some vision for future developments in these areas.
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Advances in Helium Cryogenics
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10.1007/0-387-46896-X_9
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2006-12-01
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The implementation of an Evolution Algorithm (EA) for the cryogenic noise modeling of microwave devices has been the object of the present work. Several approaches exist to treat the modeling issue as far as advanced microwave transistors are concerned. The aim of such procedures is mostly oriented to extract a linear equivalent circuit including noise performance that allows to reproduce the global device behavior in a small signal regime. In the present paper, the authors show how EA’s can be employed to solve the noise modeling problem according to a black-box approach. The application refers to the simulation of the Noise Parameters of High Electron Mobility Transistors (HEMT) in the 6-18 GHz frequency range and down to cryogenic temperatures (90K) compared with experimental data. The quality of results indicates that EA techniques represent a truly alternative way to determine the microwave noise performance of HEMT devices, thus furnishing a flexible tool to support CAD of high sensitivity – ultra high speed circuits.
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An evolution algorithm for noise modeling of HEMT’s down to cryogenic temperatures
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10.1007/s10825-006-0007-8
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2006-11-01
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Interlaminar fracture and damage behavior of glass fiber reinforced polymer (GFRP) woven laminates at cryogenic temperatures is investigated for end notched flexure (ENF) pure Mode II configuration. The corrected beam theory (CBT) and finite element analysis (FEA) are used to calculate the Mode II interlaminar fracture toughness of ENF specimen at room temperature (RT), liquid nitrogen temperature (77 K) and liquid helium temperature (4 K). A FEA coupled with damage is also employed to study the damage distributions within the specimen and to examine the effect of damage on the Mode II energy release rate. The numerical results show that damage occurs at the matrix and causes a decrease in the energy release rate. The technique presented can be efficiently used for the characterization of cryogenic Mode II interlaminar fracture and damage behavior of woven laminate ENF specimens.
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Analysis of mode II interlaminar fracture and damage behavior in end notched flexure testing of GFRP woven laminates at cryogenic temperatures
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10.1007/s00707-006-0357-0
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2006-10-01
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The effect of sodium chloride and technical-grade carbon (carbon black) on the mechanical and thermal properties of cryogels and foamed cryogels produced from homogeneous and heterogeneous (foamed) solutions of poly(vinyl alcohol) was studied.
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Mechanical and thermal properties of cryogels and foamed cryogels produced from aqueous solutions of poly(vinyl alcohol)
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10.1134/S1070427206100235
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2006-10-01
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NIST has developed an extensive collection of environmental SRMs, starting with fuel and biologically related materials in the late 1960s and now encompassing all sectors of environmental research. Advances in analytical methodology, including multi-element isotope-dilution mass spectrometry (IDMS) and expanded instrumental neutron-activation analysis (INAA) capabilities, enable value assignment based on fewer but better-characterized independent analytical techniques. The special advantages of IDMS for determination of S and Hg and for multi-element characterization of small-sample air particulate matter (SRM 2783) by IDMS and INAA are emphasized. Developments in materials production include the issuance of fresh-frozen biological materials and of jet-milled natural-matrix materials with improved homogeneity, including highly homogeneous air particulate matter and sediment SRMs for small-sample analytical techniques.
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Standard Reference Materials^® (SRMs) for measurement of inorganic environmental contaminants
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10.1007/s00216-006-0785-7
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2006-09-01
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The carbon dioxide freezing phenomenon is investigated at the cryogenic operating conditions of the turbo-expansion-based NGL plants. The Peng-Robinson equation of state is used for predicting the CO_2 freezing points for liquid and vapor mixtures of CO_2-CH_4. A new quadratic temperature dependent k_ ij correlation is also presented for proper description of binary interactions at low temperatures. The overall average absolute relative deviation between experimental and predicted CO_2 freezing temperatures is 0.26%.
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Prediction of CO_2 freezing points for the mixtures of CO_2-CH_4 at cryogenic conditions of NGL extraction plants
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10.1007/BF02705935
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2006-09-01
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Traceability in illuminance measurements at the National Metrology Institute of Turkey (TÜBITAK-UME) was established in 2003 with a detector-based realization. The new measurement technique was developed for the determination of illuminance responsivity and upgrating of the illuminance scale. The unit of the illuminance responsivity, in A/lx, was measured with an expanded uncertainty of 0.2% ( k = 2) by supplying using the developed scanning technique for the calculation of color correction factor. The surface of a radiometer was scanned using a double-monochromator facility upgraded with an x-y scanning system. The illuminance responsivity as a function of bandpass and temperature were also investigated in this study. To use a radiometer in the photometric applications of metrology, a light-sensitive device, a so-called trap detector, was characterized by measuring the absolute responsivity, the non-linearity, and spatial non-uniformity.
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Establishment of Illuminance Scale at UME with an Accurately Calibrated Radiometer
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10.1007/s10043-006-0326-9
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2006-09-01
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This paper deals with mode III delamination properties of glass fiber reinforced polymer woven laminates at room temperature (293 K), liquid nitrogen temperature (77 K), gas helium temperature (20 K), and liquid helium temperature (4 K). In order to evaluate these properties, the Split Cantilever Beam (SCB) fracture test is performed. The load is applied to a test specimen through a set of identical grips in order to reduce (in some degree) the mode II loading at the free edges. A three-dimensional finite element analysis is used to study the stress and strain state of the specimens and to interpret the experimental measurements. The strain energy release rate is calculated by using the virtual crack closure technique. It is found that the strain energy release rate is dominated by the mode III component. A non-uniform distribution of the strain energy release rate along the delamination front is obtained with mode III component having maximum at the center of the delamination front, while mode II component increases towards the free edges. The strain energy release rate is also determined using the crack closure technique. A finite element analysis is also carried out to calculate the stress intensity factors for the SCB specimens. The fracture surfaces are examined by scanning electron microscopy to identify the fracture mechanisms. The most important conclusion from the present study is that at temperature lowering from 293 to 20 K the mode III fracture toughness increases, further cooling to 4 K produces a toughness decrease.
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Mode III Interlaminar Fracture Behavior of Glass Fiber Reinforced Polymer Woven Laminates at 293 to 4 K
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10.1007/s10443-006-9008-9
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2006-07-01
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In general, to send out natural gas via a pipeline network across the nation in LNG terminal, high-pressure cryogenic pump supply highly compressed LNG to high-pressure vaporization facilities. The Number of cryogenic pumps determined the send-out amount in LNG receiving terminal. So it is main equipment at LNG production process and should be maintained on best conditions. In this paper, to find out the cause of high vibration at cryogenic pumps-motor system in LNG terminal, vibration spectrum analysis and motor current signature analysis have been performed together. Through the analysis, motor rotor bar problems are estimated by the vibration analysis and confirmed by the current analysis. So, it is demonstrated through the case study in this paper, how performing vibration analysis and current signature analysis together can reliable diagnosis rotor bar problems in pump-motor system.
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Diagnosis of cryogenic pump-motor systems using vibration and current signature analysis
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10.1007/BF02915996
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2006-07-01
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Vacuum infusion (VI), freezing, frozen storage and thawing conditions were optimized in order to minimize the texture loss of frozen strawberries. Slow freezing caused severe loss in textural quality of the strawberries. This quality loss could not be prevented by the application of VI prior to slow freezing, or by the application of rapid, cryogenic or high-pressure shift freezing conditions on non-infused fruits. A remarkable texture improvement was noticed when infusion of pectinmethylesterase (PME) and calcium was combined with rapid or cryogenic freezing. The highly beneficial effect of PME/Ca-infusion followed by HPSF on the hardness retention of frozen strawberries was ascribed to the combined effect of the infused PME (53% reduction in degree of esterification (DE) of the strawberry pectin) and the high degree of supercooling during HPSF. During frozen storage, textural quality of PME/Ca-infused high-pressure frozen strawberries was maintained at temperatures below −8 °C, whereas the texture of PME/Ca-infused strawberries frozen under cryogenic freezing conditions was only preserved at temperatures below −18 °C. Thawing at room temperature seemed to be an appropriate method to thaw strawberries. Fast thawing by high-pressure induced thawing (HPIT) did not prevent textural quality loss of frozenstrawberries.
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Minimizing texture loss of frozen strawberries: effect of infusion with pectinmethylesterase and calcium combined with different freezing conditions and effect of subsequent storage/thawing conditions
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10.1007/s00217-005-0218-4
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2006-06-01
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Fluid turbulence is a paradigm for non-linear systems with many degrees of freedom and important in numerous applications. Because the analytical understanding of the equations of motion is poor, experiments and, lately, direct numerical simulations of the equations of motion, have been fundamental to making progress. In this vein, a concerted experimental effort has been made to take advantage of the unique properties of liquid and gaseous helium at low temperatures near or below the critical point. We discuss the promise and impact of results from recent helium experiments and identify the current technical barriers which can perhaps be removed by low temperature researchers. We focus mainly on classical flows that utilize helium above the lambda line, but touch on those aspects below that exhibit quasi-classical behavior.
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The Use of Cryogenic Helium for Classical Turbulence: Promises and Hurdles
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10.1007/s10909-006-9221-9
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2006-06-01
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A Fourier Transform Infrared Spectrometer (FTS) was used to obtain the transmission spectra of candidate materials for use as infrared (IR) filters in cryogenic receivers. The data cover the range from 50 cm^−1 (∼1.5 THz), well below the peak of the 300 K black body spectrum, to 5000 cm^−1 (∼150 THz), Z-cut quartz, Goretex, Zitex G and Zitex A, High Density Polyethylene (HDPE), Teflon (PTFE), Fluorogold and Black Polyethylene were measured. The relative effectiveness of each material as a filter is determined by integrating the transmission spectrum multiplied by the Planck distribution to obtain a normalized attenuation for the mid-IR band. Measurements at both room temperature and 8 K are compared.
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INFRARED MEASUREMENTS OF POSSIBLE IR FILTER MATERIALS
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10.1007/s10762-006-9121-8
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2006-06-01
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Effect of cryogenic treatment on the microstructure, hardening behavior and abrasion resistance of 14Cr2Mn2V high chromium cast iron (HCCI) subjected to subcritical treatment was investigated. The results show that cryogenic treatment after subcritical treatment can obviously improve the hardness and abrasion resistance of HCCI because abundant retained austenite is transformed into martensite and fine secondary carbides [(Fe, Cr)_23C_6] precipitate. The amount of martensite and precipitated secondary carbide in HCCI experiencing subcritical treatment followed by cryogenic treatment was more than that experiencing the subcritical treatment followed by air cooling. When the abrasion resistance of HCCI reaches the maximum, its microstructure contains about 15% retained austenite. Cryogenic treatment can further reduce the austenite content but the retained austenite cannot be transformed into martensite completely.
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Effect of Cryogenic Treatment on Property of 14Cr2Mn2V High Chromium Cast Iron Subjected to Subcritical Treatment
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10.1016/S1006-706X(06)60108-8
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2006-05-01
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The CRESST experiment is looking for non-baryonic particle dark matter via nuclear scattering in CaWO_4. The simultaneous measurement of the heat and the scintillation light generated by an event in a CaWO_4 single crystal is used to discriminate between electron and nuclear recoils thanks to their different light output. This allows an efficient suppression of the electron recoil background. The set-up consists of modules with a 300 g CaWO_4 crystal mounted in a reflective housing together with a light detector. The heat signal is read out using a superconducting transition-edge sensor (TES) made of tungsten evaporated directly on to the crystal that is operated at a few mK. Currently the second phase of the experiment is being set up at the Laboratori Nazionali del Gran Sasso in which it is planned to run 33 detector modules providing a total target mass of 10 kg. First test runs with prototype detectors have been successfully performed.
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Dark-matter search with CRESST
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10.1007/s10582-006-0118-2
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2006-04-01
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This paper is concerned with an Eulerian finite element analysis for the steady state forming of porous materials, such as nano-grained material manufactured via cryogenic milling. The constitutive relation for such porous materials is different from that for a fully dense matrix. The general form of the constitutive equation for a porous material is derived from the yield functions for the plastic deformation of a porous material, as proposed by Shima, Green, Doraivelu, Gurson, Kuhn, Park, and Lee. Then, that general form is utilized in the Eulerian finite element formulation for the strain hardening, dilatant, and viscoplastic deformation. Initial estimation of the porosity distribution in an Eulerian mesh is obtained from the velocity and scaled pressure fields computed by the Consistent Penalty finite element method for the incompressible viscoplastic deformation of the matrix. Applications of the proposed method to rolling and extrusion are given. The change of the porosity is predicted by integrating its evolution equation along a particle path constructed in an Eulerian domain. Comparisons of the predicted distributions of porosity to those by a Lagrangian finite element method and to those by experiments reported in the literature validate the proposed method.
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An Eulerian finite element model for the steady state forming of porous materials
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10.1007/BF03027473
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2006-04-01
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Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing.
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Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM
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10.1007/s11998-006-0013-6
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2006-02-01
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Mechanical properties in conjunction with microstructural evolution during annealing of 5052 Al alloy deformed at cryogenic temperature were investigated and compared with those yielded by the ARB process. ARB was conducted up to 7 cycles under conditions where the reduction in thickness per cycle was 50% and the rolling temperature was 300°C. To investigate the effect of annealing temperature, cryo-rolled sheets with 85% reduction were annealed in a temperature range of 150≈300°C for one hour. Strengths of 5052 Al alloy ARB processed at 300°C increased with increasing number of cycles and decreased rapidly after 6 or 7 cycles. This indicated that, during the ARB process, work hardening proceeded at low strains and subdivision of grains and dynamic recovery occurred at high strains. Tensile strength and yield strength of cryo-rolled 5052 Al alloy decreased as the annealing temperature increased. The volume fraction of recrystallized and coarsened grains appeared to have the most significant influence on strength and ductility in sheets annealed at 250°C.
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Mechanical properties of ultrafine grained 5052 Al alloy produced by accumulative roll-bonding and cryogenic rolling
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10.1007/BF03027516
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2006-01-01
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Characterization of the OPA350 Operational Amplifier at Cryogenic Temperatures
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10.1007/1-4020-4330-9_77
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2006-01-01
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This chapter describes some simple standard operating procedures for the regular collection of samples from surgical resections and their rapid preservation by freezing for long-term cryogenic storage.
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Frozen Biopsy Collection and Storage
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10.1385/1-59259-969-9:25
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2006-01-01
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It is shown how the airy and nival conditions of cryogenic eolation affect the structural changes and weakening of gold-qnartz sulfide ores under cyclic exposure to frost-penetration and thaw. It is revealed that leaching of ores after cryogenic eolation in the nival conditions and additional pretreatment is more intensive, by 25%, than leaching of ores that were not prepared by cryogenic eolation.
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Study of cryogenic disintegration of gold-quartz ores to intensify the heap leaching of gold
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10.1007/s10913-006-0034-7
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2006-01-01
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Aluminum alloys are widely used for constitutive parts of aircrafts and are consequently confronted with a wide range of temperature depending on altitude: from 300K (ambient temperature) on the ground down to 223K during a fly. Fatigue properties and particularly fatigue crack growth resistance at low temperature have been poorly studied. The literature provides results in cryogenic condition (77K) showing improved fatigue strength in Al-Li alloys [ 1 , 2 ]. This paper deals with a study of the fatigue crack propagation behavior of two high strength 2xxx Aluminum alloys elaborated in naturally-aged and peak-aged conditions.
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Fatigue Crack Propagation in 2XXX Aluminium Alloys at 223K
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10.1007/1-4020-4972-2_494
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2006-01-01
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Severe plastic deformation (SPD) has been known to be an effective method for producing nanostructured materials [ 1 ]. Examples of SPD methods are mechanical alloying and mechanical attrition to prepare nanostructured powders. The same concept can be used to develop a nanocrystalline surface region in bulk materials thus enhancing surface sensitive properties [ 2 ].
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Surface Nanostructured Aluminum by Severe Plastics Deformation
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10.1007/1-4020-4972-2_334
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2006-01-01
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First CDMS II WIMP Search Results from the Soudan Underground Laboratory
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10.1007/3-540-26373-X_12
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2006-01-01
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Low temperature operation with utilization of refrigeration as cooling electronic devices. In this chapter we review the low operation of the system has shown improvement in performance and the reliability of CMOS devices and describe different cooling solution for low temperature operation.
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Low Temperature CMOS Operation
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10.1007/0-387-29749-9_6
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2006-01-01
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Following the detection of low-level impurities in pharmaceuticals, structural characterization of these components represents a continuing challenge. Irrespective of whether the impurity in question arises from side reactions of the chemical processes being employed for the synthetic elaboration of the active pharmaceutical, through degradation chemistry processes, or through accidental contamination, the identification of low-level impurities is a mandatory component of the preparation and marketing of pharmaceuticals. The development of cryogenic NMR probes and the corresponding increases in sensitivity that they provide has significantly impacted this phase of pharmaceutical development. The role of cryogenic NMR probe technology in the characterization of low-level impurities from pharmaceuticals is discussed.
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Applications of Cryogenic NMR Probe Technology for the Identification of Low-Level Impurities in Pharmaceuticals
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10.1007/1-4020-3910-7_129
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2006-01-01
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To gain information on fullerene formation, the production methods based on the evaporation of graphite are outlined. In particular, the effects of the buffer gas temperature are considered in connection with experiments performed with a laser furnace arrangement. In addition, fullerene formation by incomplete combustion and by pyrolysis is discussed. The former method is presently applied for large-scale fullerene production and very likely is also the source of most of the fullerenes occurring on earth. The formation processes based on evaporation and on combustion seem to be vastly different indicating that various chemical reaction routes lead to fullerenes.
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Formation of Fullerenes
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10.1007/1-4020-4135-7_2
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2005-12-01
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The friction and wear properties of the prevailing different solid lubricant coatings (Ion-plated Au, Ion-plated Ag and RF-sputtered PTFE on SUS440C stainless steel) used in the bearings of high-speed cryogenic-turbo-pumps of liquid rocket engines were experimentally evaluated in liquid nitrogen immersed conditions. Also the above experiments were carried out with two newly proposed solid lubricant coatings of sputter-ion-plated MoSTi and a new ion-plated Pb on SUS440C stainless steel. The friction coefficient and wear rates of the coatings of ion-plated Au, ion-plated Ag, RF-sputtered PTFE, the new ion-plated Pb and MoS_2Ti-SIP (with coating thickness of 0.7±0.1 μ m) on SUS440C steel against SUS440C stainless steel ball in liquid nitrogen were compared. Worn surfaces were examined microscopically with a microscope and a profilometer for understanding the mechanisms of friction and wear and transfer film lubrication in liquid nitrogen. It is found that the newly proposed solid lubricant coatings are showing promising results for their use in liquid nitrogen immersed conditions. The sputter-ion-plated MoSTi coating on SUS 440C steel shows a minimum value of friction coefficient ( μ =0.015) and wear rate ( w _c=0.56 × 10^−6 mm^3/N m ) in liquid nitrogen.
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Experimental Evaluation of Friction and Wear Properties of Solid Lubricant Coatings on SUS440C Steel in Liquid Nitrogen
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10.1007/s11249-005-9066-4
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2005-11-01
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Die Entwicklung effizienter und „sauberer“ Wasserstoffspeichertechnologien für zukünftige Fahrzeuge ist ein Schlüssel zur Sicherung der individuellen Mobilität von morgen. Die heute verfügbaren Wasserstoffspeicher erfüllen noch nicht die hohen Anforderungen des Automobilbaus und letztendlich des Endkunden. Die Entwicklungsmöglichkeiten für die verschiedenen automotiven Speichertechnologien für Wasserstoff und deren Aussichten stehen im Mittelpunkt dieses Artikels. Efficient and clean hydrogen storage technologies for future vehicles will be crucial to secure our future individual mobility. State-of-the-art hydrogen storage systems do net yet fulfil the stringent requirements of the automotive industry and the final customer. Future development targets and prospects for different automotive hydrogen storage systems shall be discussed in this article.
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Wasserstoffspeicherung im Fahrzeug
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10.1007/BF03054320
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2005-10-01
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Accurately predicting the coefficient of thermal expansion for many aerospace components is critical to ensure proper functionality on orbit where the temperature gradient across a spacecraft can vary from +300 °F to −450 °F. Under these conditions, the linear approximations generated by theoretical equations no longer hold true, and experimental methods are needed. Although several methods exist for measuring the coefficient of thermal expansion of materials, laser interferometry yields high-resolution results, and the technique is widely accepted in the scientific community.
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High-resolution methods for measuring the thermal expansion coefficient of aerospace materials
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10.1361/105994905X64602
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2005-06-01
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The digital signal-obtaining for gyroscope is given. The single optic-fiber sensor via modulating intensity of light is used as measuring component. The influence on static transmission properties resulting from the special working environment (e.g. cryogenic and vacuum), the measure error because of the reflector shape of rotor, the abnormity of facula from sensor caused by the existence of engraving error, and the fixing error of sensor and the error of machine tool’s initial lignment are investigated. The mathematic model in every condition is founded, the simulation and relative experiments are done and the outcome is analyzed. The mathematic model and method of compensating technology are studied and some relative experiments are made. The result of study is useful to improvement of the signal-obtaining system.
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Analysis of signal-obtaining error factor of sensor in gyro
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10.1007/s11804-005-0029-9
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2005-06-01
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The microstructural evolution during annealing of a cryogenically ball-milled Al-7.5Mg-0.3Sc (in wt pct) was examined using differential scanning calorimetry and transmission electron microscopy (TEM). The as-milled alloy was a supersaturated fcc solid solution with an average grain size of ∼25 nm and heterogeneous grain morphologies and size distributions. Calorimetric measurements at a constant heating rate of 32 K/min indicated two exothermic events in association with recovery from 100 °C to 240 °C and recrystallization from 300 °C to 450 °C. Prior to recrystallization, the precipitation of Al_3Sc may occur at low annealing temperatures producing a nonuniform dispersion of approximately spherical particles with diameters of 4 to 5 nm. Recrystallization gave rise to heterogeneous microstructures with bimodal grain size distributions, which may result from the heterogeneity of microstructure in the as-milled state. The heterogeneous microstructures of the recrystallized Al-Mg-Sc alloy were similar to those observed in the recrystallized Sc-free Al-Mg alloy.
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The influence of Sc on thermal stability of a nanocrystalline Al-Mg alloy processed by cryogenic ball milling
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10.1007/s11661-005-0250-9
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2005-05-01
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The compression behaviors of well-annealed coarsegrained (CG) and ultrafine-grained (UFG) 5083 Al alloys at 77 and 298 K were compared. For the CG alloy, stage II and III strain hardening were dominant at 77 and 298 K, respectively, depending on the completeness of dislocation cell formation. The UFG alloy exhibited the elastic-near perfectly plastic behavior without distinctive dislocation cell formation at both temperatures. For both alloys, the flow stress at 77 K was much higher than that at 298 K.
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Comparison of compressive deformation of ultrafine-grained 5083 Al alloy at 77 and 298 K
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10.1007/s11661-005-0227-8
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2005-05-01
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This paper covers the absolute spectral power responsivity calibration of spectralon-coated Integrating Sphere Radiometer (ISR) equipped with 3 mm diameter InGaAs photodiode to be used as a transfer standard in fiber optic power measurements against Electrical Substitution Cryogenic Radiometer (ESCR) in Optics Laboratory of National Metrology Institute (TUBITAK UME) of Turkey. The initial uncertainty arising from the use of the Electrically Calibrated Pyroelectric Radiometer (ECPR) as a transfer standard in radiometric scale is 0.5% ( k =2), which particularly comes from irregularity in the surface homogeneity of ECPR. In order to eliminate the ECPR step as well as its initial uncertainty contribution in fiber optic power measurements, the calibration application herein was carried out. Moreover power stabilization measurements of DFB laser sources at both 1309.1 nm and 1549.0 nm, the beam size determinations, and spectral analyses of these laser sources as well as spatial and angular dependence of spectral responsivities of the ISR were presented in this paper. The total expanded uncertainties were calculated as 0.283% and 0.315% in the determination of absolute spectral power responsivities of the ISR for 1309.1 nm and 1549.0 nm wavelengths respectively ( k =2).
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Cryogenic radiometer based absolute spectral power responsivity calibration of integrating sphere radiometer to be used in power measurements at optical fiber communication wavelengths
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10.1007/s11082-005-3955-5
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2005-04-01
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The liquid nitrogen as an environmentally safe coolant has been widely recognized in cryogenic machining, its function as a lubricant is plausible due to its chemical inertness, physical volatility and low viscosity. Since a reduced friction is a direct witness of the lubrication effect from a tribological viewpoint, this paper presents an evaluation of the apparent friction coefficient on the tool-chip interface in cryogenic cutting operations to prove and characterize the lubricity of LN2 in cryogenic machining. The cryogenic cutting technology used in this study is based on a cooling approach and liquid nitrogen delivery system which are intended to apply liquid nitrogen in well-controlled fine jets to selectively localized cutting zones and to penetrate liquid nitrogen to the tool-chip interface. It has been found that the apparent friction coefficient can be significantly reduced in cryogenic machining, depending on the approach of liquid nitrogen delivery.
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Lubrication effect of liquid nitrogen in cryogenic machining friction on the tool-chip interface
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10.1007/BF02919176
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2005-03-01
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Effect of annealing temperature on tensile behavior of 5052 Al alloy deformed at cryogenic temperature
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10.1007/s10853-005-6960-y
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2005-03-01
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Features typical of the use of standard detectors of ultraviolet radiation and the basic problems that arise in the construction of a scale of radiation flux and illuminance in the region of vacuum and near ultraviolet radiation are considered. The principal results and new trends in the design of an ultraviolet radiometric scale using standard ultraviolet radiation detectors in research carried out at national metrological institutes are described.
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Reproduction and Dissemination of the Units of Radiation Flux and Irradiance Using Standard Ultraviolet Radiation Detectors
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10.1007/s11018-005-0129-6
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2005-03-01
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Despite the on-going development of room temperature semiconductors for use as gamma-ray detectors, the only material which can provide a solution to the combined requirements of stability, high-energy resolution and high-detection efficiency (at useful energies) is still germanium (HPGe). These properties of HPGe gamma-ray detectors make them invaluable in meeting the demands of the newly emergent and increasingly important applications relating to homeland security and the interdiction of smuggled nuclear material. However, HPGe detectors require cooling to cryogenic temperatures (<120 K) to operate as gamma-ray detectors. Traditionally, this cooling has been accomplished with liquid nitrogen (LN2). The use of LN2 as a coolant is, at best, inconvenient. Maintenance, operating cost, availability at remote locations, and the hazardous nature of the material all combine to limit the practicality of a LN2-cooled device, no matter how desirable it might be from other standpoints. Mechanical methods of achieving cryogenic temperatures have existed for many years. The first mechanically-cooled HPGe systems appeared commercially in the early 1980s.^1 These systems had high cost, high power requirements, degraded system performance, were bulky in size, and unreliable. Other developments have produced prototype versions of portable (or transportable) mechanically-cooled HPGe systems. More recent advances in mechanical cooling technologies have the potential to make HPGe detectors easily adaptable to a wide variety of applications including battery-operated, truly man-portable systems for use in inspection, unattended monitoring, and Homeland Security. The major problems of mechanical coolers are degraded performance due to vibration and power consumption. The systems described here have reduced both of these to useable limits. The vibration or microphonic noise created in real-world systems is significantly reduced by optimizing the digital filter technology in the signal processing electronics associated with such detectors. Data presented here show reliability and performance results of the mechanically-cooled systems. These results show the improvements gained through the use of the optimally-matched digital filters.
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New cooling methods for HPGE detectors and associated electronics
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10.1007/s10967-005-0684-y
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2005-02-01
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The influence of cryogenic deformation on Bi2223 superconducting tapes has been investigated in this paper. Mechanical deformation was carried out on Ag-sheathed mono- and multi- filamentary tapes and silver alloy-sheathed multi- filamentary tapes at liquid nitrogen temperature (77 K) and room temperature, respectively. Results show that the critical current of the Bi2223 tapes is significantly enhanced by cryogenic deformation. SEM microstructure observations show that the cryogenic-tapes have higher core density, smoother silver/superconductor interface, and better grain alignment. Tensile tests indicate that the tapes pressed at liquid nitrogen temperature have better tensile behavior than those pressed at room temperature.
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The influence of cryogenic deformation on Bi2223 superconducting tapes
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10.1007/BF03027485
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2005-02-01
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Annealing behavior of 5083 Al alloy deformed at cryogenic temperature
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10.1007/s10853-005-6327-4
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2005-01-01
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This paper describes the design, development, testing, and performance of the Ball Aerospace SB235 and SB235E long life, 2-stage space cryocoolers optimized for dual temperature simultaneous cooling at 35 K and above. The SB235 and its model derivative SB235E are 2-stage coolers designed to provide simultaneous cooling at 35 K (typically, for HgCdTe detectors) and 100 K (typically, for the optics) and were baselined for the Raytheon SBIRS Low Track Sensor. A qualification unit SB235 was developed and has accumulated 2500 hours in a life test at the Air Force Research Laboratory (AFRL). The SB235 and its higher capacity derivative SB235E were designed for high cooling capacity, power and mass efficiency, and producibility for multiple unit build applications.
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Ball Aerospace Next Generation 2-Stage 35 K SB235 Coolers
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10.1007/0-387-27533-9_9
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2005-01-01
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Moderately and heavily boron doped polysilicon-on-insulator layers before and after laser recrystallization were studied at cryogenic temperatures in high magnetic fields up to 14 T. Piezoresistance and magnetoresistance of poly-Si layers with different carrier concentration were investigated. It was shown that laser-recrystallized poly-Si layers could be used to develop piezoresistive sensors, operating at cryogenic temperatures and high magnetic fields.
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Polysilicon-on-Insulator Layers at Cryogenic Temperatures and High Magnetic Fields
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10.1007/1-4020-3013-4_34
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2005-01-01
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Direct-drive inertial confinement fusion (ICF) creates extreme states of matter. In current direct-drive cryogenic target implosions on the 60-beam OMEGA laser system, the compressed target has a measured pressure of 5 Gbar. These targets are hydrodynamically scaled from ignition targets for the National Ignition Facility. The ignition targets are predicted to have peak pressures of 3 Tbar after the target ignites. ICF target acceleration and deceleration are realized when hot, low-density plasma pushes against cold, high-density plasma, making the target implosion inherently susceptible to the Rayleigh-Taylor hydrodynamic instability (RTI). The unstable RTI growth causes mixing of cold, high-density shell plasma with the low-density, hot-spot plasma and reduces the primary neutron yield of the implosion. The strategy to control the RTI growth is to reduce the seeds (e.g., laser imprint and target-surface roughness) and the growth rates of the dominant modes. This paper reports on our recent experiments, progress in validating the hydrodynamics codes that are used to design future high-gain cryogenic DT targets, and techniques to improve target performance. A brief description is given of a new high energy petawatt laser — OMEGA EP (extended performance) — that is being added to the OMEGA compression facility.
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Direct-Drive Inertial Confinement Fusion Implosions on Omega
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10.1007/1-4020-4162-4_32
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2005-01-01
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A test facility has been upgraded in preparation for testing of two hydrogen sorption cryocoolers operating at 18/20 K. These sorption coolers are currently under development at the Jet Propulsion Laboratory (JPL) for the Planck mission sponsored by the European Space Agency (ESA). The two units share the same process and component design with different plumbing configurations required for spacecraft integration. Previous effort at JPL has led to the successful demonstration of a prototype of the sorption cooler. Each flight unit of the sorption cooler will be tested in a vacuum chamber with simulated background environment for the spacecraft. GM cryocoolers, bulk LN2, and a chiller unit are used to establish nominal temperature stages at 50, 100, and 280 K, respectively, allowing the cold end of the sorption cooler to operate at 18/20 K. This work summarizes the scope of the test facility upgrade, including design for cryogenic cooling power delivery, system thermal management, insulation schemes, and data acquisition techniques. Ground support equipment for the sorption coolers, structural features of the test chamber, and the vacuum system involved for system testing are also described in detail.
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Cryogenic Testing of Planck Sorption Cooler Test Facility
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10.1007/0-387-27533-9_66
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2005-01-01
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Heat Transfer Issues in Cryogenic Catheters
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10.1007/1-4020-3361-3_24
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2005-01-01
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Long-life, highly reliable and low-cost miniature Stirling cryogenic coolers are the core components in a wide variety of cryogenically cooled electro-optic, high temperature superconductive and vacuum applications. The linear compressors of such coolers are known to be the major source of harmful vibration disturbances affecting the operation of these inherently vibration sensitive systems. The dual-piston approach to the design of the linear compressor yields intrinsically low vibration export and, therefore, is widely accepted across the industry. However, the residual vibration export originated from unavoidable technological tolerances, natural wear and contamination cannot be completely eliminated. The ultra-low vibration export from a dual-piston compressor may be attained using active balancing. A dedicated digital controller normally relies on internal sensors (e.g. LVDT) for direct measuring of the pistons’ motion or an external sensor (e.g. accelerometer or load cell) for measuring the residual vibration export. This eventually complicates the entire design and makes the cooler more expensive and less reliable. The authors disclose the recent efforts made by Ricor towards the development, implementation and testing of a sensorless adaptive feed-forward controller for the balancing of dual-piston compressors. In this novel approach, the detection and synchronization of the pistons’ velocities relies solely on the real-time data acquisition (motors’ voltages and currents) and the general model of the linear “moving coil” or “moving magnet” motor. The attainable performance of the controller was evaluated through the full-scale testing performed on the Ricor model K535 linear dual-piston Stirling cryogenic cooler.
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Sensorless Balancing of a Dual-Piston Linear Compressor of a Stirling Cryogenic Cooler
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10.1007/0-387-27533-9_33
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2005-01-01
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Physical Properties of Paints
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10.1007/3-540-26644-5_3
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2005-01-01
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Low vibration Stirling cryocoolers often rely on dual-piston linear compressors, the known disadvantages of which, as compared to their single-piston rivals, are: low reliability, increased power consumption, price, bulk, sensitivity to external vibration and g-forces. However, because of the inherently low level of vibration export, as required in numerous vibration sensitive electronic and electro-optic applications, the dual-piston approach has become prevalent in today’s industrial practice. The authors report on the novel patent pending approach to the passive control of a fundamental component of a vibration export from a single-piston compressor down to the levels typical for the actively controlled dual-piston rival. The technique relies on the principle of dynamic counterbalancing, where an auxiliary movable mass is, on the one hand, flexibly attached to a movable piston assembly and, on another hand, to the stationary compressor casing using auxiliary mechanical springs. The proper design of such a “spring-mass-spring” counterbalancer yields zero vibration export at minimum electrical power and current consumed by the motor. Based on the theoretical analysis, the design of the single-piston compressor of 1 W at 77 K Ricor model K529N Stirling cryocooler was enhanced by adding such a counterbalancer. The obtained experimental results are in full agreement with the theoretical prediction. From experiment, the vibration export at driving frequency was reduced 57-fold at practically the same electrical current and power consumption as compared with the basic cooler.
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Dynamically Counterbalanced Single-Piston Linear Compressor of a Cryogenic Cooler
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10.1007/0-387-27533-9_34
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2005-01-01
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A 90 K freezer, currently named CRYOSYSTEM, will support biological and medical experiments on board the International Space Station. The samples produced are intermediately stored under cryogenic conditions and downloaded to ground for further examination. Typical samples are animal tissue, organs, and plants, as well as organic fluids and protein crystals. A Development Model (DM) of the freezer has been manufactured and tested by AIR LIQUIDE. The system is composed of a vacuum insulated shell equipped with a revolving magazine capable of freezing and storing up to 880 2-ml vials. The cryogenic cooling is produced by an engineering model Stirling cryocooler specially adapted for the needs of CRYOSYSTEM from a THALES Cryogenics BV tactical cryocooler. This paper presents test results regarding the quick freezing of liquid samples, the snap freezing of solid samples, and the capability of the freezer to withstand power-off periods and to recover within the allocated time. Some preliminary correlations with ESATAN predictions are discussed.
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Cryogenic Tests of a Development Model for the 90 K Freezer for the International Space Station
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10.1007/0-387-27533-9_82
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2004-12-01
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An additional cryogenic effect will be reported obtained on hypo-eutectic FeB alloys. After resting the samples at low temperature (such as liquid N_2, 77 K), the decrease in H solubility was detected by measuring the time dependence of pressure change in a hermetically closed chamber. The cryogenic treatment also caused a systematic lowering of the Curie temperature of the amorphous phase (T _C ^am ), similarly to that, observed in other types of Fe-based glasses.
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The Influence of Low Temperature Treatments on the H Solubility and the Curie Temperature of Fe-B Based Glasses
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10.1007/s10582-004-0048-9
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2004-10-01
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Effects of the annealing temperature on microstructures and mechanical properties of 5052 Al alloy that have received 88% reduction at cryogenic temperature were investigated for an annealing temperature range of 150–300°C, in comparison with those at room temperature. Equiaxed grains, approximately 200nm in diameter, were observed in 5052 Al alloy deformed 88% and annealed at 200°C for 1 h. When compared with the deformation at room temperature, the deformation at cryogenic temperature showed higher strengths and equivalent elongation after annealing at temperatures below 200°C. However, for annealing above 250°C, materials deformed at cryogenic temperature showed lower strength than those deformed at room temperature. This behavior might be attributable to the higher rate of recrystallization and growth in materials deformed at cryogenic temperature during annealing, due to the lager density of dislocations accumulated during the deformation.
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Effect of deformation temperature on the formation of ultrafine grains in the 5052 Al alloy
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10.1007/BF03027340
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2004-09-01
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Use of LNG cryogenic technology during refining of associated petroleum gases
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10.1007/s10556-005-0003-z
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2004-05-01
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The solubility of solid 2-methyl-1,3-butadiene (isoprene) in liquid argon at a temperature of 87.3 K and in liquid nitrogen at 77.4 K has been measured by the filtration method. The hydrocarbon contents in solutions were determined using gas chromatography. GC–MS was used to identify impurities in the solute. The experimental value of the mole fraction solubility of solid isoprene in liquid argon at 87.3 K is (1.41 ± 0.27) × 10^−6 and (1.56 ± 0.36) × 10^−7 in liquid nitrogen at 77.4 K. The Preston–Prausnitz method was used for calculation of the solubilities of solid hydrocarbon in liquid argon in the temperature range 84.0–110.0 K and in liquid nitrogen from 64.0 to 90.0 K. The solvent–solute interaction parameters l _12 were also calculated. At 90.0 K liquid argon is a better solvent for isoprene than is liquid nitrogen. The experimental values of the solubilities of isoprene in liquid argon and nitrogen were compared with results obtained for selected unsaturated and aromatic hydrocarbons.
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Solubility of Solid 2-Methyl-1,3-butadiene (Isoprene) in Liquid Argon and Nitrogen at the Standard Boiling Points of the Solvents
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10.1023/B:JOSL.0000037770.79717.48
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2004-03-01
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An automated system for calculating thermophysical properties of gases and liquids over a wide range of parameters has been developed. On the basis of values of the properties, the processes of isothermal compression, adiabatic throttling, polytropic expansion, heat exchange in two- and multi-stream heat exchangers, separation of vapor-liquid mixtures in the liquid vessel, and rectification in an air separation plant can be analyzed. For a specified structure scheme of a cryogenic plant, optimization of a corresponding thermodynamic cycle can be fulfilled.
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Automated System for Calculating Thermophysical Properties of Fluids and Thermal Processes of Cryogenic Plants
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10.1023/B:IJOT.0000028474.99046.60
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2004-03-01
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The modification of the microrelief and structure of the surface layers of ribbons of an amorphous metal alloy based on iron and cobalt after thermal treatment at elevated and cryogenic temperatures and under the action of an external magnetic field is studied by the method of light scattering. The parameters of the surface roughness were calculated from the experimentally found indicatrices of light scattering. It is shown that heating of the metal ribbons to T =650–750 K partially relieves stresses arising in the course of the ribbon preparation and reduces the surface roughness as compared to that of freshly prepared samples. Cryogenic treatment at T =78 K increases the surface roughness, and application of a magnetic field to a ribbon causes anisotropy in the surface layer due to the magnetostrictive effect.
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Light scattering by the surface of amorphous alloy ribbons modified by annealing and cryogenic treatment
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10.1134/1.1651257
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2004-02-01
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Metallo-supramolecular diblock copolymers consisting of a polystyrene (PS) block connected to a poly(ethylene oxide) (PEO) block by a bis(terpyridine)ruthenium complex (PS_20-[Ru]-PEO_ y ) were used to prepare aqueous micelles. The length of the PS block was kept constant, while two PEOs of different molecular weight were used. The resulting hydrated micelles and aggregates were characterized by a combination of cryogenic transmission electron microscopy (cryo-TEM) and dynamic light scattering measurements. The results were compared to those obtained for a covalent counterpart (PS_22- b -PEO_70). Cryogenic transmission electron microscopy allowed visualization of the PS core of the micelles. Moreover, the aggregates result from clustering of individual micelles.
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Dynamic light scattering and cryogenic transmission electron microscopy investigations on metallo-supramolecular aqueous micelles: evidence of secondary aggregation
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10.1007/s00396-003-0975-1
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2004-02-01
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The influence of cryogenic mechanical milling on the structure and the thermal behavior of isotactic polypropylene was investigated by means of wide-angle X-ray scattering, differential scanning calorimetry and transmission electron microscopy. The results presented show that structural changes caused by mechanical milling at cryogenic temperatures are only partly reversible. The decrease in the degree of crystallinity as determined by differential scanning calorimetry with increasing milling time is attributed to a reversible transformation of the initial morphology into a “nanostructured” morphology, consisting of small “fragments” of the original isotactic polypropylene lamellae. During recrystallization from the molten state, there still exists an influence of the previous milling treatment, leading to significantly changed crystallization behavior. The reason for this behavior might be a decrease in the molecular weight or a change in the molecular weight distribution or the formation of long-chain branched polypropylene molecules induced by cryogenic mechanical milling.
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Irreversible structural changes in cryogenic mechanically milled isotactic polypropylene
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10.1007/s00396-003-0953-7
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2004-01-01
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The analysis of service conditions for the elements of a superconducting electromagnetic system of thermonuclear reactor is performed. Based on the study of the peculiarities of deformation and fracture of alloys subjected to an electric pulse current and cryogenic temperatures, criteria for the ultimate state of the materials are established and the methods for their determination are outlined.
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The Ultimate State of Structural Alloys for Superconducting Electromagnetic System of Thermonuclear Reactor
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10.1023/B:STOM.0000020238.29969.55
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2004-01-01
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The rapid advance of ultrashort amplified laser technology into a mature research tool has inspired its widespread use. Such laser pulses, with durations of less than 10 fs, are exclusively generated by using gas-filled capillaries with subsequent chirped-mirror compression [1]. Direct amplification of ultrabroadband laser pulses to high energies (millijoule region) still poses a challenging problem. Thermally induced lensing, gain-narrowing and phase aberrations during amplification reduce the ability to obain ultrashort pulses at a higher energy level with a good beam quality. These problems have been addressed in a number of variants, such as cryogenic cooling of the gain material, spectral filtering and phase control via adaptive shaping or specially designed mirrors and pulses shorter than 16 fs have been reported [2] [3]. Another promising approach, first proposed by Danailov et al . [4] employs a spatially dispersed seed beam inside an amplifier to decouple the amplification of competing wavelengths from each other. With this an artificial inhomogeneous broadening is induced in the Ti:sapphire, which is normally homogeneously broadenend, which makes it possible to tailor the gain profile. The effective gain factor of each wavelength component is only determined through the dedicated pump intensity profile. As a result, gain-competition between different wavelength components, and red-shifting of the spectrum can be eliminated provided that the individual wavelength channels are sufficiently decoupled from each other inside the gain medium. The implementation of such a dispersive amplifier has been previously reported [5], but compression to yield amplified ultrashort pulses was never demonstrated.
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Generation of 14.8-fs Pulses in a Spatially Dispersive Amplifier
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10.1007/978-0-387-34756-1_8
|
2004-01-01
|
In this paper, the way of deep cryogenic treatment of electrodes for spot welding hot dip galvanized steel is put forward firstly to improve electrode life. Electrodes are treated by deep cryogenic treatment way with different deep cryogenic treatment parameters. Deep cryogenic treatment electrodes life experiment is carried out. The electrical conductivities of the deep cryogenic treatment electrodes and the non-deep cryogenic treatment electrodes are tested The SEM area scanning and the SEM back scattering of the electrodes are canied out The grain degree of deep ayogenic treatment electrodes and the non-deep cryogenic treatment electrodes are tested by X-Ray Diffraction. The experimental results show that deep cryogenic treatment makes Cr, Zr in deep cryogenic treatment electrodes emanate dispersedly and makes the grain of deep cryogenic treatment electrodes smaller than non-cryogenic treatment ones, so that the electrical conductivity and the thermal conductivity of deep cryogenic treatment electrodes are improved very much, which make electrode life for spot welding hot dip galvanized steel improve obviously.
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Deep Cryogenic Treatment Electrodes Life and Microstructure for Spot Welding Hot Dip Galvanized Steel
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10.1007/978-1-4471-0647-0_33
|
2004-01-01
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The World Reference Base for Soil Resources (ISSS Working Group RB, 1998) classification includes permafrost-affected soils in three groups. The first is the Histosol major soil group, which includes both perennially frozen (Cryic, Glacic and Gelic lower-level units) (ISSS Working Group RB, 1998, pp. 13, 76) and unfrozen organic soils. The second is the Cryosol major soil group, which includes all of the perennially frozen mineral soils that have a cryic horizon (ISSS Working Group RB, 1998, pp. 14, 30). The third includes those soils in the Leptosol, Fluvisol, Solonchak, Gleysol, Podzol, Planosol, Albeluvisol, Umbrisol, Cambisol, Arenosol, and Regosol major soil groups (ISSS Working Group RB, 1998, pp. 76–78) that have permafrost at depths of 100 to 200 cm.
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Classification of Permafrost-Affected Soils in the WRB
|
10.1007/978-3-662-06429-0_33
|
2004-01-01
|
The most often used stainless steel grades for cryogenic applications are the AISI grades 304, 304L, 316, 316L and 316LN. Sometimes the grades 316Ti and 321 were used for low temperature service, however the recent studies show their rather limited applicability. An important feature of the above mentioned stainless steel grades is the presence of large amount of chromium reaching some 16 ÷ 20% as well as reduced amount of carbon of around 0.030.08% (specially limited in the grades denoted L). Also, all these grades are characterised by the presence of significant amount of nickel (8 ÷ 14%), which stabilises the austenitic matrix at cryogenic temperatures. A controlled addition of nitrogen (N) improves the yield point and the tensile strength when compared to the traditional grades. The other important elements in the chemical composition of stainless steels are: Si (around 1%), Mn (around 2%), Mo (up to 3%), S (around 0.03%) and P (around 0.05%). In the grades 316Ti, 321 titanium is present to the upper limit of 0.7%. Composition of typical grades of wrought stainless steel for low temperature use is shown in Table 3.1 (as quoted in the ASTM and ASME specifications, cf. INGO Databook, 1974).
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Properties of Austenitic Stainless Steels at Cryogenic Temperatures
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10.1007/978-3-662-06305-7_3
|
2004-01-01
|
Successful operation of a system over a scheduled period of “ n ” years depends very much on the reliability of all its structural components (Kovalenko et al. 1997). A poor reliability of a group of components may yield a sequence of failures that will make smooth operation of the system impossible. Thus, an investment in the reliability oriented optimum design may reduce considerably the number and the total cost of repairs and interventions associated with chance and wearout failures.
|
Reliability Oriented Optimum Design Of Cryogenic Compensation Systems
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10.1007/978-3-662-06305-7_8
|
2004-01-01
|
As already mentioned in the previous chapters, the Fe-Cr-Ni stainless steels are commonly used to manufacture components of superconducting magnets and cryogenic transfer lines since they retain their ductility at low temperatures and are paramagnetic. The nitrogen strengthened stainless steels of series 300 belong to the group of metastable austenitic alloys. Under certain conditions the steels undergo martensitic transformation at cryogenic temperatures that lead to a considerable evolution of material properties and to a ferromagnetic behaviour. The martensitic transformations are induced mainly by plastic strain fields and amplified by high magnetic fields. Spontaneous transformations due to the cooling process — identified with respect to some alloys — are not observed in the most often used grades 304L, 304LN, 316L, 316LN. The stainless steels of series 300 show at room temperature a classical γ -phase of face centred cubic austenite (FCC). This phase may transform either to α ′ phase of body centred tetragonal ferrite (BCT) or to a hexagonal ε phase. The most often occurring γ — α ′ transformation leads to formation of martensite sites dispersed in the surrounding austenite matrix. In the course of the strain induced transformation the martensite platelets modify the FCC lattice leading to local distortions. The amount of the martensite depends on the chemical composition, temperature, stress state, plastic strains and exposure to magnetic field. It is well known that the solutes like Ni, Mn and N considerably stabilise the γ -phase. For instance the strain induced martensitic content in the grades 304LN, 316LN at low temperatures is much lower than in the grades 304L, 316L for the same level of plastic strain (Morris et al. 1992).
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Strain Induced Martensitic Transformation at Low Temperatures
|
10.1007/978-3-662-06305-7_5
|
2004-01-01
|
Exquisite properties of HTS filters employed in the base station receivers of cellular systems lead to reduced adjacent channel interference, increased coverage and better spectrum utilization, and hence increase the revenue for the communication service providers. There are approximately 1,500 HTS front-end mobile radio receivers working commercially in the USA and Asia, and they are predicted to make a significant impact on the third and fourth generations of wireless communication. This Chapter presents a brief history of superconducting materials and microwave properties of high-temperature superconducting(HTS) films, reviews designs and properties of HTS resonators and filters, shows cryogenic HTS base station receivers available on the market, and summarizes possible trends in this field.
|
High-Temperature Superconducting Planar Filters for Wireless Communication
|
10.1007/978-1-4757-4156-8_6
|
2004-01-01
|
Usually security of energy supply means diversified provisions and infrastructure development. Sometimes special precautions are required, as for instance when stretching a gas pipelines through a transit country. In this event security of supply would include pre-emptive actions to ensure stability on a long-term basis. One initiative is to enable the transit country to prosper from the option gas that it receives as compensation for land lease. This article addresses LNG as an alternative to pipeline distribution. In contrast to natural gas LNG requires no firm pipeline infrastructure, as it is transported as a bulk commodity in cryogenic tanks on road, rail and sea. The article suggests that countries that lack a well-developed gas distribution system may draw upon recent experience from countries that employ LNG, as for instance Norway. Although Norway is among the largest exporters of natural gas in the world, the domestic outlook is that natural gas will be introduced to the Norwegian energy system basically in liquid phase. The paper describes vital elements pertaining to the LNG chain. This includes the provision and distribution of LNG, principles for satellite systems, peak shaving, and suggestions on how LNG can be used as a fuel for prime movers in ships and vehicles. As cryogenic tanks are integral parts of any LNG concept, some tank concepts and containers are presented. Eventually, the combination of small-scale LNG provision and large tank volumes may offer a viable alternative to underground storage of natural gas (UGS).
|
On the Relevance of Integrating LNG with the Energy Supply Systems of Transit Countries
|
10.1007/1-4020-2078-3_6
|
2004-01-01
|
The corrugated bellows work often in extremely severe service conditions comprising temperature variations between ambient and operational level, high internal pressure, large cyclic axial offset and different types of misalignment offsets. This implies development and evolution of plastic strain fields in these components subjected to thermo-mechanical loads at low temperatures. The evolution of plastic strain fields is usually accompanied by two phenomena: ductile damage and strain induced martensitic transformation (already discussed in the previous chapters). Cryogenic temperatures catalyse the process of opening of micro-cracks and micro-voids shifting simultaneously deformations towards the elastic domain (considerable increase of yield strength). Nevertheless, the behaviour of corrugated bellows, highly optimised with respect to their size and stiffness, is affected by the low cycle fatigue phenomena.
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Material and Fatigue Induced Structural Instabilities of Corrugated Bellows at Low Temperatures
|
10.1007/978-3-662-06305-7_7
|
2004-01-01
|
A super-high strength cast and wrought aluminum alloy with specific strengths exceeding that of a Ti-5Al-2.5Sn alloy and tensile ductility of about 10% or higher, both at room and cryogenic temperatures, has been developed by modifying the composition and heat treatment of a 7XXX series alloy. This aluminum alloy is a potential candidate to replace the more expensive titanium alloy, which is currently used in some cryogenic rocket engine applications. Microstructure and tensile properties of the aluminum alloy after casting, extrusion and forging and after different heat treatment are presented and the effect of processing parameters on the properties is discussed.
|
High Strength Aluminum Alloys for Cryogenic Applications
|
10.1007/1-4020-2112-7_15
|
2004-01-01
|
Micromorphological analysis makes it possible to study the interrelationships between the various individual components, particles, and pores that make up sediments and soils.
|
Micromorphology of Cryosols
|
10.1007/978-3-662-06429-0_18
|
2004-01-01
|
As long as the stress-strain curve is smooth (mechanism of plastic deformation based on the movement of dislocations) and below the critical strain rate the low temperature plasticity can be modelled in a classical rate independent way. For the stainless steel, that shows high ductility at cryogenic temperatures, the normality law expressed via the associated flow rule is good enough. Above the critical strain rate both the hardening modulus and the ultimate strength depend strongly on the strain rate, therefore a rate dependent plasticity shall rather be applied. A survey of different plastic and visco-plastic models, potentially applicable at cryogenic temperatures is given below.
|
Plastic Yielding and Evolution of Ductile Damage under Cryogenic Conditions
|
10.1007/978-3-662-06305-7_4
|
2004-01-01
|
Since its invention by Binnig, Quate, and Gerber [360], the scanning force microscope (SFM) has become a standard tool for the investigation of conducting and insulating surfaces on the atomic scale. Low-temperature scanning force microscopes (SFMs) are desirable for many applications in physical research. A particular field of application is the physics of mesoscopic semiconductor structures. In conventional magnetotransport experiments on such systems, the measured conductance does not give direct insight into microscopic properties within the system. On the other hand, detailed microscopic theories, e.g., based on scattering wave functions or on S-matrices, exist for the calculation of the conductance. These theories have to make assumptions about local potential landscapes in the structures in order to lead to quantitative results. It can be expected that scanning probe techniques give more detailed information about the interior of a mesoscopic system.
|
Instrumentation: Scanning force microscopes for cryogenic temperatures and magnetic fields
|
10.1007/0-387-21828-9_14
|
2004-01-01
|
Northern Canada, the vast, sparsely populated region of Canada affected by permafrost, encompasses about half (5 × 10^6 km^2) of the country and includes the Arctic and Subarctic zones and portions of the Boreal zone. This region, which is composed of the Northwest Territories, Nunavut (formerly the eastern portion of the Northwest Territories), the Yukon, and the northern portions of most provinces, has a population density of only 2 people per hundred square kilometers.
|
Northern Soil Research in Canada
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10.1007/978-3-662-06429-0_3
|
2003-11-01
|
Superconducting transition-edge sensors have been used extensively in cryogenic particle detectors, either as thermometers for microcalorimetry or as bolometers for the detection of the prompt phonons resulting from a particle decay in a single crystal absorber. Bolometer action depends upon the energy coupling of the prompt phonons to the bolometer electrons. A study has been made of the electron-phonon coupling for a series of Au-Ti bolometers on a Si substrate and of the use of these bolometers for prompt phonon detection below 1 K. The electron-phonon coupling was found to be proportional to the normalized resistance ( R / R _n) of the bolometer; R is the bolometer resistance and R _n is the normal resistance. When extrapolated to R / R _n = 1, this coupling was consistent with κ/ VT ^3 = 3 × 10^9 W⋅m^−3⋅K^−4 where κ is the thermal conductance from the bolometer electrons to the Si phonons and V and T are the volume and transition temperature of the bolometer. The response of the bolometers to heat pulses generated by a thin film heater on the opposite face of a Si single crystal were similar to that generally seen above 1 K, apart from a delay time constant that varied from ∼0.5 to ∼1.3 µs as the transition temperature decreased from 600 to 200 mK. This delay time constant is attributed to the thermal equilibrium time of normal regions of the bolometer.
|
Electron-Phonon Coupling in Bolometers Used for Cryogenic Particle Detection
|
10.1023/A:1026087225040
|
2003-10-01
|
A triple resonance NMR experiment is presented for the simultaneous recording of HNCA and HNCO data sets on ^15N, natural abundance ^13C samples. The experiment exploits the fact that transfers of magnetization from ^15N to ^13CO and from ^15N to ^13C^α (and back) proceed independently for samples that are not enriched in ^13C. A factor of 2 in measuring time is gained by recording the two data sets simultaneously with no compromise in spectral quality. An application to a 0.5 mM ^15N labeled sample of protein-L is presented with all expected correlations observed in spectra recorded with a cryogenic probe at 500 MHz.
|
A combined HNCA/HNCO experiment for ^15N labeled proteins with ^13C at natural abundance
|
10.1023/A:1024985219764
|
2003-09-01
|
Spray-atomized Al-7.5Mg-0.3Sc (in wt pct) alloy powders were mechanically milled at a low-energy level and at cryogenic temperature (cryomilling). The low-energy milling effectively generated a nanoscale microstructure of a supersaturated face-centered cubic (fcc) solid solution with an average grain size of ∼26 nm. The nanoscale microstructure was fully characterized and the associated formation mechanisms were investigated. Two distinct nanostructures were identified by transmission electron microscopy (TEM) observations. Most frequently, the structure was comprised of randomly oriented equiaxed grains, typically 10 to 30 nm in diameter. Occasionally, a lamellar structure was observed in which the lamellas were 100 to 200 nm in length and ∼24 nm wide. The morphology of the mixed nanostructures in the cryomilled samples indicated that high-angle grain boundaries (HAGBs) formed by a grain subdivision mechanism, a process similar to which occurs in heavily cold-rolled materials. The microstructural evidence suggests that the subdivision mechanism observed here governs the development of fine-grain microstructures during low-energy milling.
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Nanostructure in an Al-Mg-Sc alloy processed by low-energy ball milling at cryogenic temperature
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10.1007/s11661-003-0163-4
|
2003-09-01
|
Lamellar lyotropic liquid-crystalline systems are thermodynamically stable, optically isotropic and are formed spontaneously. New possibilities for the development of controlled drug delivery systems are inherent in these systems in consequence of their stability and special, skin-friendly structure. The aim was to formulate and study two-component or multicomponent compositions with a relatively low Brij 96V content, liquid paraffin, glycerol and water for therapeutic purposes. The liquid crystals were examined by polarizing light microscopy and transmission electron microscopic observation of replicas produced by the freeze–fracture technique to demonstrate the presence of lamellar liquid-crystalline domains. The existence of a regular structure was determined by X-ray diffraction.
|
Structural properties of nonionic surfactant/glycerol/paraffin lyotropic liquid crystals
|
10.1007/s00396-002-0851-4
|
2003-07-01
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The design of a sensor of an ultrasonic level gauge for a cryogenic liquid is described. This sensor can withstand multiple thermal cycles.
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A Cryogenic Sensor of an Ultrasonic Level Gauge
|
10.1023/A:1025171124170
|
2003-07-01
|
Universal brazing alloy for cryogenic technology
|
10.1533/wint.2003.3163
|
|
2003-07-01
|
The solubilities of solid 2,3-dimethylbutane and cyclopentene in liquid argon at a temperature of 87.3 K and in liquid nitrogen at 77.4 K have been measured by the filtration method. The hydrocarbon contents in solutions were determined using gas chromatography. GC–MS was used to identify impurities in solutes. The experimental value of the mole fraction solubility of solid 2,3-dimethyl-butane in liquid argon at 87.3 K is (8.26 ± 1.60) × 10^−6 and (2.77 ± 0.94) × 10^−8 in liquid nitrogen at 77.4 K. The experimental value of the mole fraction solubility of solid cyclopentene in liquid argon at 87.3 K is (5.11 ± 0.44) × 10^−6 and (4.60 ± 0.76) × 10^−8 in liquid nitrogen at 77.4 K. The Preston–Prausnitz method was used for calculation of the solubilities of solid hydrocarbons in liquid argon in the temperature range 84.0–110.0 K and in liquid nitrogen from 64.0 to 90.0 K. The solvent–solute interaction parameters l _12 were also calculated. At 90.0 K liquid argon is a better solvent for investigated solid hydrocarbons than is liquid nitrogen.
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Solubility of Solid 2,3-Dimethylbutane and Cyclopentane in Liquid Argon and Nitrogen at the Standard Boiling Points of the Solvents
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10.1023/A:1026340322043
|
2003-06-01
|
Methods for cryogenic fixation, freeze substitution, and embedding were developed to preserve the cellular structure and protein localization of secondary-wall-stage cotton ( Gossypium hirsutum L.) fibers accurately for the first time. Perturbation by specimen handling was minimized by freezing fibers still attached to a seed fragment within 2 min after removal of seeds from a boll still attached to the plant. These methods revealed native ultrastructure, including numerous active Golgi bodies, multivesicular bodies, and proplastids. Immunolocalization in the context of accurate structure was accomplished after freeze substitution in acetone only. Quantitation of immunolabeling identified sucrose synthase both near the cortical microtubules and plasma membrane and in a proximal exoplasmic zone about 0.2 μm thick. Immunolabeling also showed that callose (β-1,3-glucan) was codistributed with sucrose synthase within this exoplasmic zone. Similar results were obtained from cultured cotton fibers. The distribution of sucrose synthase is consistent with its having a dual role in cellulose and callose synthesis in secondary-wall-stage cotton fibers.
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Localization of sucrose synthase and callose in freeze-substituted secondary-wall-stage cotton fibers
|
10.1007/s00709-002-0079-7
|
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