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2016-03-01
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The effect of compressive, tensile, and impact deformation on the mechanical and physical properties of a complexly alloyed austenitic-ferritic steel for making springs and elastic members is studied at room and negative temperatures. The structural changes and their interrelation with the mechanical properties are analyzed.
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Changes in the Structure and Properties Under Deformation of Austenitic-Ferritic Steel at Room and Negative Temperatures
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10.1007/s11041-016-9936-4
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2016-03-01
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A set of governing equations comprising linear momentum, mass, and heat transfer is presented for thermoelastic freezing of a porous material. The theory of unsaturated freezing porous media is introduced to model deformation of concrete, a traditional building material, whose pore network is pressurized by the wet air, frozen ice, and unfrozen water. A general solution scheme is provided for the appropriate boundary conditions pertaining to the primary concrete containment in a liquefied natural gas tank, and simulated results are analyzed for fully and partially saturated non-air-entrained concrete and fully saturated air-entrained concrete. Effect of cooling rate is also demonstrated. It is found that high cooling rate results in high expansion provoked by high hydraulic pore pressure and the corresponding suppression of pore liquid freezing temperature. It is also revealed that air-entrained concrete, by allowing quick dissipation of the displaced pore water and accommodating the ensuing ice formation, shows less contraction and subsequently less crack initiating stresses than the high-porosity, non-air-entrained concrete. Similar outcomes are observed near the concrete surfaces subjected to evaporation prior to cryogenic freezing. High hydraulic pressure, induced by the delayed dissipation of excess pore water, is likely to generate at the center of surface-dried concrete walls.
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Simulation of Mass, Linear Momentum, and Energy Transport in Concrete with Varying Moisture Content during Cooling to Cryogenic Temperatures
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10.1007/s11242-016-0636-8
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2016-03-01
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The aramid fiber composite materials were processed by CNC milling machine in dye cutting and liquid nitrogen cryogenic conditions. The milling qualities and forces were analyzed, and cutting mechanism was discussed. The results show that with the increase of spindle speed, the better surface quality is only obtained in restrained 5000 r/min for the dye cutting, but in cryogenic conditions, the speed may be bigger. And at the same speed, the cryogenic ones are all more excellent than the dye ones. The cutting forces are generally lower for cryogenic than the dry ones at the same speed. The measuring instrument and material performance parameters from reference errors are the main error reason between model prediction and experimental measurements. Moreover, with the decrease of temperature, from tensile to shear fracture, the change of chip breaking improves the milling quality. In cryogenic condition, cutting force decrease and temperature drop have played a positive role for the improvement of the material cutting defects.
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Effect of cryogenic conditions on the milling performance of aramid fiber
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10.1007/s00170-015-7574-4
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2016-03-01
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We demonstrate that the superconducting film resonator can be used to accurately and quantitatively measure the microwave dielectric loss tangent of a variety of materials. Compared to traditional dielectric resonator loaded metal cavity method, it has advantage of small sample size (~2–3 orders of magnitude smaller than the old method), and much higher sensitivity to measure small loss tangent values as small as 10^−5 at around 7 GHz band at cryogenic temperatures. This method can be utilized widely in study of mechanism of microwave loss at cryogenic temperature range, which is extremely important in superconducting microwave application areas, such as novel super quantum computers.
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Measurement of dielectric loss tangent at cryogenic temperature using superconducting film resonator
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10.1007/s40094-015-0197-1
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2016-03-01
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Separation of Ne isotopes by fractionation at 28 K is studied. The number of transfer units in the upper and lower column sections is calculated with various loadings. Experimental characteristics of packed fractionation columns and examples of cascade systems constructed from them are given. A diagram of a cryogenic loop using a throttled high-pressure Ne cycle with intermediate N_2 cooling is presented. The need and capability to create a pressure difference between the columns of the various steps were justified.
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Separation of Neon Isotopes by Stepwise Fractionation at 28 K
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10.1007/s10556-016-0116-6
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2016-03-01
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High thrust rockets require high performance liquid engines for its propulsion. The thrust necessary for propulsion is produced by mixing, burning and ejecting a fuel and an oxidizer inside the thrust chamber of the engine. The engine investigated in this study is an indigenously developed semi-cryogenic engine developing a thrust of 2000 kN in vacuum. Its thrust chamber is of double walled construction, with inner wall of an indigenously developed high conductivity high ductility copper alloy and outer wall of high strength stainless steel. The inner wall operates in the elasto plastic condition due to high thermal and pressure loads. Structural failure of the chamber occurs due to repeated hot tests of the engine by low cycle fatigue (LCF), high temperature creep and thermal ratcheting of inner wall. In this paper, cyclic stress analysis of the thrust chamber is done using ANSYS (Version 16) code. A combination of Chaboche nonlinear kinematic hardening plasticity model, Voce nonlinear isotropic hardening model and Norton secondary creep model is used for copper, while bi-linear kinematic hardening model is selected for stainless steel. Steps for calibration of Chaboche and Voce model parameters from tensile and LCF tests are given in detail while published creep properties are used directly in the analysis. Stress analysis of chamber is done for 25 cycles and permissible number of hot tests evaluated based on Coffin–Manson type LCF equation.
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Cyclic Stress Analysis of a Rocket Engine Thrust Chamber Using Chaboche, Voce and Creep Constitutive Models
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10.1007/s12666-015-0799-y
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2016-02-27
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We report on the temperature dependence of single-event upsets in the 215–353 K range in a 4M commercial SRAM manufactured in a 0.15-μm CMOS process, utilizing thin film transistors. The experimental results show that temperature influences the SEU cross section on the rising portion of the cross-sectional curve (such as the chlorine ion incident). SEU cross section increases 257 % when the temperature increases from 215 to 353 K. One of the possible reasons for this is that it is due to the variation in upset voltage induced by changing temperature.
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Experimental study of temperature dependence of single-event upset in SRAMs
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10.1007/s41365-016-0014-9
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2016-02-01
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This is a discussion of the characteristics of a cryogenic radiometer and monochromatic radiation source that form part of the National primary standard GET 213–2014 for the units of absolute and relative spectral sensitivity at wavelengths from 0.25 to 14.00 μm and are intended for calibration of photodetectors with respect to spectral sensitivity.
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National Primary Standard for the Units of Absolute and Relative Spectral Sensitivity at Wavelengths from 0.25 TO 14.00 μm Get 213–2014
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10.1007/s11018-016-0869-5
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2016-02-01
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Deep cryogenic heat treatment is a supplementary process performed on steels specifically tool steels before tempering to improve the wear resistance and hardness of these materials. The carbide distribution changes via the electric current flow or the application of a magnetic field during the deep cryogenic heat treatment. Hence, the electric current and the magnetic field were applied to the samples to investigate the corrosion behavior of the deep cryogenically treated samples by electrochemical impedance spectroscopy and potentiodynamic polarization measurements. The results showed that increasing the carbide percentage and achieving a more homogenous carbide distribution during the deep cryogenic heat treatment will remarkably decrease the corrosion resistance due to a decrease in the solutionized chromium atoms in the structure as well as the increase in the martensite-carbide grain boundaries (the galvanic cell areas). Moreover, it was clarified that the electric current flow and magnetic fields reduce the carbide percentage, which leads to an increase in the corrosion resistance of these samples in comparison with the deep cryogenically treated samples.
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Effect of Carbide Distribution on Corrosion Behavior of the Deep Cryogenically Treated 1.2080 Steel
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10.1007/s11665-015-1858-6
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2016-02-01
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We analyzed changes in cell composition of umbilical cord blood and functional activity of hematopoietic stem cells during cryogenic storage and after repeated freezing/thawing cycles. It was found that repeated freezing/thawing cycles performed according to the optimal programmable freezing protocol did not significantly affect viability and functional activity of hematopoietic stem cells. When fast freezing program was used, the cells completely lost their capacity to form colonies in semisolid medium, despite high viability parameters in the test with 7-AAD.
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Changes in Cell Composition of Umbilical Cord Blood and Functional Activity of Hematopoietic Stem Cells during Cryogenic Storage and Repeated Freezing/Thawing Cycles
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10.1007/s10517-016-3220-x
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2016-02-01
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The mechanical alloying of Au–Co mixtures, which are systems with high positive mixing enthalpy, is studied following high-pressure torsion deformation at room and cryogenic temperatures. X-ray diffractometry in synchrotron radiation and scanning microscopy are used to investigate the sequence of structural changes in the course of deforming the mixtures up to the end state of the fcc substitutional solid solution based on gold. The mechanical properties of the alloys are measured both during mixture processing and after mechanical alloying. Microfractographic studies are performed. Factors that facilitate the solubility of Co in Au, namely, increased processing pressure, cobalt concentration in a charge mixture, true strain, and temperature decreased to cryogenic level have been identified.
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The formation, structure, and properties of the Au–Co alloys produced by severe plastic deformation under pressure
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10.1134/S0031918X16020125
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2016-02-01
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The principles underlying the construction of primary standard detectors and sources of ultraviolet radiation are considered. A double ionization chamber, proportional counter, and cryogenic radiometer with electrical displacement are used as the standard radiation detectors while synchrotron radiation the spectral characteristics of which are described on the basis of Schwinger’s theory serves as the standard source. Results of international key comparisons that confirm the high accuracy of the methods and instruments that have been developed at the All-Russia Research Institute of Optophysical Measurements (VNIIOFI) are presented.
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Spectroradiometry of Ultraviolet Radiation
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10.1007/s11018-016-0873-9
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2016-02-01
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The perforated plate is one of the effective devices for measuring flow rate accurately. In this study, a perforated plate is investigated for its characteristics, mainly including discharge coefficient C and pressure loss coefficient ζ , when applied to cryogenic fluids with the help of ANSYS Fluent. Three cryogenic fluids are studied, including liquid nitrogen (LN_2), liquid oxygen (LO_2), and liquid hydrogen (LH_2). For comparison, two states of water are also investigated. The realizable κ - ε model with standard wall function is used to describe the turbulence and simulate the near-wall flow. The Schnerr-Sauer cavitation model is used to investigate the effect of cavitation on the performance of the perforated plate. Simulation results indicate that the upper limit of Reynolds number of the perforated plate is significantly dependent on the properties of the measured fluid when the temperatures of the fluids are set as the normal boiling point temperatures and the outlet pressures are 0.2 MPa. 目 的 相较于常温流体,低温流体的物性存在显著不同,因而对流量计的工作特性也会带来相应的影响。本文旨在探讨多孔板应用于低温流体流量测量时的性能(即流出系数与压力损失系数)特征。 创新点 基于数值研究结果,发现多孔板流量计应用于低温流体流量测量时,其稳定测量区间上限雷诺数显著增大,并基于物性特点从空化特性的角度探讨上限雷诺数显著增大的原因。 方 法 采用数值模拟的方法,经网格独立性验证(表1和图5)和模型验证(图6 和图8)后,结合Realizable κ - ε 湍流模型与Schnerr-Sauer 空化模型,研究同一种结构的多孔板应用于液氮、液氧、液氢三种低温流体和水流量测量时其流出系数与压力损失系数变化的异同(图11、图12和表5);并基于低温流体的物性特点(表3),对其具有较大上限雷诺数的计算结果进行原因分析。 结 论 对于同一种多孔板结构,与水相比,低温流体具有较宽的稳定雷诺数测量范围,其中,与多孔板结构相关的下限雷诺数差异较小,而受空化影响的上限雷诺数差别较大;低温流体具有较大的上限雷诺数,其原因在于,与水相比较,低温流体的密度与运动粘度平方的乘积 ρv ^2明显较小
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Numerical study on performance of perforated plate applied to cryogenic fluid flowmeter
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10.1631/jzus.A1500082
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2016-02-01
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We studied drag reduction, rheological behavior, and cryogenic transmission electron microscopy (cryo-TEM) imaging of aqueous solutions of a cationic surfactant, Arquad 16–50 (5 mM) (commercial cetyltrimethylammonium chloride, CTAC), with two series of isomer counterions at 5 mM: 3-, 4-, and 5-methylsalicylate, and 3-, 4-, and 5-chlorosalicylate. All these systems demonstrated viscoelastic behavior at room temperature and showed effective drag reduction in the temperature range of 20–70 °C. The additional Cl- or CH_3- group on the salicylate extended the upper effective drag reduction temperature limit 5–10 °C higher than that of sodium salicylate solution. The 4-methylsalicylate, and 3- and 5-chlorosalicylate solutions are effective drag reducers down to 5 °C, the lowest temperature tested in the flow loop. All of the methyl isomers had very similar rheological behaviors, while the chloro isomers exhibited dramatic differences. The 5-chlorosalicylate system had near zero N _1, but did show viscoelastic behavior by showing recoil after swirling and overshoot at shear startup. Cryo-TEM images show that four of the isomer systems formed threadlike micellar nanostructures, but 3-methylsalicylate aggregated into vesicles and open vesicles. The 3-chloro and 5-chlorosalicylate showed vesicles with a few spherical micelles and threadlike micelles. It is postulated that the vesicles were transformed into threadlike micelles under shear and that this structure made them effective drag reducers.
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Comparison of the effects of methyl- and chloro-substituted salicylate counterions on drag reduction and rheological behavior and micellar formation of a cationic surfactant
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10.1007/s00397-015-0904-5
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2016-01-01
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China has become one the largest energy consumer in the world due to the rapid growth of its economy, leading to the steady increase in the consumption of LPG, LEG and LNG in recent years. Therefore, urgent demands for the steels to be able to contain liquefied gases had emerged. Nickel containing cryogenic steels had been mainly used for liquefied gas tanks as ferritic cryogenic materials, but there are still many problems in regard of industrial production. In the present work, the optimized processing routes for 5Ni and 9Ni steels were developed at laboratory. The effect of Ni addition on the microstructure and cryogenic toughness of Ni containing steels was investigated. The results showed that the prior austenite grain size decreased from 19.8µm to 18.2µm and the ductile-brittle transition temperature decreased as Ni content increased from 5% to 9%. The quenched and tempered microstructures in 5Ni and 9Ni steels were consisted of tempered martensite and small amount of reversed austenite, with the microstructure of 5Ni steel only containing only 0.3%reversed austenite and a large amount of dispersive cementite was precipitated on ferritic matrix. With the increase of Ni addition up to 9%, the volume fraction of reversed austenite increased to about 5% and cementite precipitation was eliminated because the reversed austenite had absorbed carbon atoms from the matrix. It has been shown that cementite was harmful to the toughness of the steelas a hard second phase because it was easy for cracks’ initiation and propagation when the cementite was precipitated at grain boundaries or lath boundaries. Fine grain size, more reversed austenite and less cementite precipitation are worked out to be the key factors to decrease the ductile-brittle transition temperature of 9Ni steel. By applying the research results, the total tonnage of more than 20,000 tons of 5Ni and 9Ni steel plates has been successfully manufactured in NISCO with its 3500mm steckel mill, which possess excellent cryogenic temperature toughness and have already applied to LNG/LEG ships and tanks. The average impact energy at −196°C for 9Ni steel plates was measured to be 198J, and the average impact energy at −135°C for 5Ni steel plates was measured to be 285J.
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The Development of Ni-Containing Cryogenic Steels and Their Industrial Manufacturing
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10.1007/978-3-319-48765-6_111
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2016-01-01
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The rise of LNG as a green fuel, in the face of global warming, is leading to the use of relatively small, vacuum insulated VI tanks for 1–100 m^3 capacity of pressurised LNG. Such tanks have been widely used over many years for the supply of nitrogen, oxygen and argon as cryogenic liquids. They are called ‘zero-boil-off Liquid Gas Cylinders’, and they have never been a problem for unstable evaporation of the cryogenic liquid contents. This chapter describes how this handling behaviour also applies to LNG.
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Vacuum Insulated Tanks for Pressurised LNG
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10.1007/978-3-319-20696-7_7
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2016-01-01
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Besides for liquid nitrogen (LN), equipment to deliver other cryogens for dermatological purposes is available. Carbon dioxide can be shaped to adapt to lesions or areas to be frozen for cryotherapy and ablation; Carbon dioxide gas dispensing units are available. Nitrous oxide dispensing equipment is in the market. Some units as small as pens, using cartridges of the above gasses compressed are also available. So are units that dispense cryogenic mixtures. A unit that externally cools tips is featured as well.
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Dispensing Units (Carbon Dioxide, Nitrous Oxide, etc.)
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10.1007/978-1-4471-6765-5_15
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2016-01-01
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Significant improvement in mechanical properties of tool steels may be obtained by cryogenic heat treatment at temperatures as low as 77K. However, the selection of the cryogenic temperature can significantly influence the final properties. In the present study, AISI D2 tool steel was cryogenically treated at 183K and 77K. Microstructural studies using scanning electron microscope (SEM) and image analyzing process revealed higher volume fraction of fine secondary carbides for both cryogenically treated alloys in comparison with conventionally treated one. Higher volume fraction of fine secondary carbides was observed when the cryogenic treatment temperature was reduced to 77K. Also, the volume fraction of large carbides has been reduced after both cryogenic treatments. Tensile test results revealed simultaneous enhancement of ultimate tensile strength, higher elastic modulus (E) and increased ductility for cryogenically treated alloy at 183K. More improvement was observed when the cryogenic temperature reduced to 77K.
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Influence of Cryogenic Treatment on Microstructure Characteristics and Mechanical Properties of Aisi D2 Tool Steel
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10.1007/978-3-319-48237-8_117
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2016-01-01
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Potential of Comprehensive Two-Dimensional Gas Chromatography for the Analysis of Lipids
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10.1007/978-94-007-7864-1_70-1
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2016-01-01
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The paper is devoted to the Allan variance usage for output signal fluctuation analysis of weak signal receivers. The tri-band microwave receiving system for the new radio telescope RT-13 of Institute of Applied Astronomy of Russian Academy of Sciences is considered. The Allan variance correction for signals with «dead time» in data acquisition is developed. Output stability of the receiver is investigated in terms of noise fluctuation type – white, flicker, drift, etc., and their time stability intervals calculation. Investigations are performed in S -, X -, and Ka - receiver bands. The influence of the input cryogenic stage temperature on output receiver signal is considered also.
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The Allan Variance Usage for Stability Characterization of Weak Signal Receivers
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10.1007/978-3-319-46301-8_56
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2016-01-01
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Results of an experimental investigation into the deformation and destruction of a metal composite vessel with a cryogenic gas are presented. Its structure is based on basalt, carbon, and organic fibers. The vessel proved to be serviceable at cryogenic temperatures up to a burst pressure of 45 MPa, and its destruction was without fragmentation. A mathematical model adequately describing the rise of pressure in the cryogenic vessel due to the formation of a gaseous phase upon boiling of the liquefied natural gas during its storage without drainage at the initial stage is proposed.
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Mechanical Behavior of A Metal Composite Vessels Under Pressure At Cryogenic Temperatures
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10.1007/s11029-016-9542-y
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2016-01-01
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Examples of the application of a cryogenic moderator in the REMUR time-of-flight neutron reflectometer of the IBR-2 pulsed reactor (Dubna) are given. The results of two experiments are presented: spatial beam splitting upon reflection from a magnetically noncollinear film and the recording of a microbeam formed by a layered waveguide. A conclusion concerning the efficiency of the cryogenic moderator for experiments of this type is made.
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Application of a cryogenic moderator in the REMUR neutron reflectometer
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10.1134/S1027451016010146
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2016-01-01
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In this study, Taguchi method has been applied to evaluate the effect of cryogenically treated tools in turning of Hastelloy C22 super alloy on surface roughness. The optimum parameters (cryogenic treatment, cutting speed, and feed rate) of turning were determined by using the Taguchi experimental design method. In Taguchi method, L9 orthogonal array has been used to determine the signal noise (S/N) ratio. Analysis of ANOVA was carried out to identify the significant factors affecting surface roughness. The statistical analysis indicated that feed rate, with a contribution percentage as high as 87.64 %, had the most dominant effect on machining performance, followed by the cryo-treated tools treatment and cutting speed, respectively. The confirmation tests indicated that it is possible to improve surface roughness significantly by using the Taguchi method. Surface roughness was improved by 28.3 and 72.3 % by shallow (CT1) cryogenic treatment and deep cryogenic treatment (CT2) applied on cementite carbide tools (UT). It found that wear resistance of tungsten carbide insert was increased by shallow and deep cryogenic treatments.
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The effects of cryogenic-treated carbide tools on tool wear and surface roughness of turning of Hastelloy C22 based on Taguchi method
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10.1007/s00170-015-7356-z
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2016-01-01
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If two non-boiling liquids at ambient temperatures are mixed (say diesel and gasoline fuels) the heat of mixing causes the temperature of the mixture to rise; that’s all. If two LNG liquids with different compositions, or LPG liquids, are mixed at atmospheric pressure, the heat of mixing will create a large volume of boil-off vapour. This chapter introduces this and other differences between ambient temperature and cryogenic temperature liquid mixtures, which need to be understood by all users. The chapter begins with a summary of 15 points towards efficient storage, handling and use, together with some recommendations to prevent stratification and unstable evaporation behaviour, including roll-over. The chapter concludes with a list of definitions of terms used throughout this monograph.
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Advisory Summary and Introduction to LNG (and LPG)
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10.1007/978-3-319-20696-7_1
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2016-01-01
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The present chapter encloses the primary objective of this research work, at which most of the invested time and efforts have been devoted; this is the design and development of an experimental system to perform in situ RR experiments at the end of one of the beam lines of a Tandetron ion-irradiation facility. Such task requires the acquisition, design and assembling of every component of the setup and the acquisition system, testing of sensors and probes (sensibility and performance), developing of data acquisition program, and optimizing the measurement methodology as well as the data warehousing and treatment. Additionally, a specific method for the specimen preparation and assembly in the developed setup had to be invented. The experimental technique has turned out to be very exigent from a technical point of view as it will be explained along the chapter. As explained in Chap. 2 , a classical RR experiment consists of monitoring the residual resistivity Residual resistivity of a metallic sample after irradiation at low temperature. It is measured at cryogenic temperature, typically 4.2−30 K, in order to eliminate the electron–phonon contribution to the resistivity and get a resistivity value dependent on point defects and “ordering” of the sample lattice. The low-temperature irradiation is going to create defects in the sample lattice which would increase its residual resistivity. This phenomenon is called RIR Radiation Induced Resistivity (RIR) and has been described above. A step-like thermal annealing subsequent to irradiation will typically lead to a recovery of non-irradiated residual resistivity values providing the RR curves. The derivative of such curve provides indirect information on the migration processes that created defects perform. Hence, information related to damage creation, recombination, and clustering of defects Clustering Defect clustering , both vacancies and interstitials, can be obtained by performing this type of experiments. This section provides a detailed explanation of the experimental techniques and methods used for the resistivity measurements, as the choice of the appropriate probe configuration and measurement methodology is non-straightforward in the case of metallic samples with very low values of electrical Probe Electrical probes resistance. The four-point probe Probe Four-point probe method technique in the particular configuration of van der Pauw (VdP) [ 1 ] has been chosen to prepare the sample (Sect. 3.1 ), and the delta method has been used for clean measurement of low voltages by removing the thermoelectric voltage contributions (Sect. 3.2 ). Beyond these basic concepts, the Sect. 3.3 outlines the requirements and difficulties for undertaking the RR measurements on samples irradiated at cryogenic temperature. The details concerning the sample preparation method, designed in order to fulfill the experimental requirements, is given in Sect. 3.4 . An explanation of experimental details and highlight of the technological difficulties needed to be overcome in such experiments are also presented as this discussion is interesting in order to understand the reliability and comparability among results from different authors. In particular, in Sect. 3.5 , the design of the sample holder which assembles all the systems for resistivity measurements, heating and temperature monitoring is carefully described as it is a fundamental piece to guarantee the success of the RR measurements. Finally, in Sect. 3.6 , an effort has been made to provide good explanation of the measurement details and procedure and to treat the whole uncertainties of a resistivity measurement in a clear and sincere way because in literature this issue is normally omitted. For readers interested in developing their own RR experimental setup, I also recommend, as complementary sources of information, to read the reference literature from former works [ 2 – 8 ].
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Experimental on Resistivity
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10.1007/978-3-319-38857-1_3
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2016-01-01
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Experimental vibration certification of launcher cryogenic tanks is an important issue in the aerospace industry. Liquid hydrogen is indeed too dangerous to be used in tank vibration tests. Unlike most fluids used in aerospace industry such as liquid oxygen, surrogate fluids cannot be used to approach the modal behavior of a tank filled with liquid hydrogen because of its particularly low mass density. However granular materials could safely replace liquid hydrogen for vibration testing of tanks.This work aims at proposing an innovative methodology to determine the geometry and the material properties of substitution grains in order to keep the same mode shape and eigen frequencies of a vertical cylindrical tank studied considering 2D horizontal slices. Assuming that the tank slices are sufficiency far enough from the free-surface not to be affected by sloshing effects, the fluid-structure interaction is purely inertial. This methodology is based on the homogenization of a granular material composed of spheres with an elastic behavior. Thus the tank filled with grains can be modeled by a membrane surrounded by a circular beam. An experimental test bench developed to validate the methodology, as well as analytical and numerical simulation results of fluid-beam and membrane-beam interactions, are presented on the first modes.
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Surrogate Granular Materials for Modal Test of Fluid Filled Tanks
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10.1007/978-3-319-29910-5_14
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2016-01-01
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Quasi-gley chernozems of the Trans-Baikal region are characterized by the clearly pronounced anisotropy of their properties related to carbon sequestration processes. The main carbon pool is concentrated in the humus horizon; the organic carbon content sharply decreases down the soil profile. The pool of organic carbon in the cryogenic fissures is two to three times higher than its pool in the enclosing soil horizons. The analysis of stable carbon isotopes in the plants and soils attests to the predominance of C3 plants. The composition of stable carbon isotopes is clearly differentiated in the soil profile with an increase in the portion of heavy isotopes in the deep horizons. In the humus pockets and cryogenic fissures, the increase in the portion of heavy carbon isotopes with the depth is weaker, which attests to a lower degree of the organic matter transformation. It is probable that the organic matter in the fissures is younger than the organic matter in the enclosing soil mass and derives from the upper humus horizon. The organic matter in the cryogenic fissures preserves the evolutionary properties of humus from the upper horizons.
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The pool of organic carbon and its isotopic composition in cryomorphic quasi-gley chernozems of the Trans-Baikal region
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10.1134/S106422931507011X
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2016-01-01
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This investigation reports the effect of thermal shock of different gradients, i.e., immediate transition from high temperature to cryogenic environment and vice versa on the flexural properties of Al_2O_3 particulate reinforced Cu metal matrix micro- and nano-composites fabricated by powder metallurgy route. The specimens were also thermally conditioned at high as well as sub-zero temperatures separately. The specimens were subjected to 3-point flexural test followed by fractography, and the fracture micro-characteristics were studied under field emission scanning electron microscopy and transmission electron microscopy to predict the dislocation behavior under induced thermal stresses and mismatch. The degree of improvement in flexural strength is higher for the composites experiencing lower degree of thermal shock, i.e., improvement in flexural strength is higher for a thermal shock of 80 °C than for 160 °C temperature gradients. Particle pull-out, crack entrapment, and physical outgripping of alumina particles act as the operative mechanisms during fracture of thermally shocked composites.
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Implications of Degree of Thermal Shocks on Flexural Properties of Cu-Al_2O_3 Micro- and Nano-composites
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10.1007/s11665-015-1832-3
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2016-01-01
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Strain calibration measurements are performed for acrylate coated, substrate-free fiber Bragg grating (FBG) sensors at room temperature of 298 K and cryogenic temperature of 77 K. A 1550 nm Bragg wavelength (λ_B) FBG sensor, with its sensing part not being bonded to any surface, is subjected to axial strain using MTS25 tensile machine available at Cryogenic Material tests Karlsruhe (CryoMaK), KIT. The Bragg wavelength shift (Δλ_B) versus induced strain (ε) is regressed with a linear polynomial function and the strain sensitivity obtained is found to be 0.9 pm/µε at both the temperatures, verifying that the FBG strain sensitivity is independent of temperature.
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Strain Calibration of Substrate-Free FBG Sensors at Cryogenic Temperature
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10.1007/978-3-319-47075-7_24
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2016-01-01
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Every year, people have died from accidents with cryogenic liquids. The enormous volume expansion of 600 to one for LNG, and 350 to one for LPG, takes everyone by surprise when there is a leakage or accidental spill. The vapours are non-toxic and odourless, and can easily reduce the oxygen level below that needed for respiration. There is no physiological warning of oxygen deficiency, and asphyxia will kill very quickly. If handling a cryogenic liquid in a confined space, beware of the danger of asphyxia: carry a reliable oxygen meter to provide continuous monitoring of the air you are breathing. This chapter includes a number of advisory points on safety by the author, from some 60 years of storing, handling and carrying out research on all kinds of cryogenic liquids, including LNGs, LPGs and Freon mixtures.
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Safe Handling and Storage of LNG and LPG
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10.1007/978-3-319-20696-7_9
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2016-01-01
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The thermal state of high-temperature superconductor current leads is considered upon changes in the current density. A change of the thermal regime in the resistive section and at a point of contact between a normal conductor and superconductor is described. The factors limiting the current density in current leads are revealed. An analytical method to determine allowable density in current leads is presented. At such a density, the maximum temperature of resistive section is no higher than the given allowed value and contact region temperature is no higher than the critical temperature of superconductor transition into a normal state. Analytical equations determining temperature distribution in the resistive section and normal conductor of contact part are derived. An equation determining contact length, in which the temperature is lower than critical one depending on the taken maximum allowed temperature of resistive section, is given.
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Current density in HTSC current leads
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10.3103/S1068371216010028
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2016-01-01
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There has been a substantial growth in using carbon fiber-reinforced plastic (CFRP) composite materials in aerospace and automotive industries due to their superior properties. This experimental study presents results from a comprehensive and systematic study investigating the effects of cryogenic cooling on drilling performance and surface integrity characteristics of CFRP composite material. Experimental data on cutting edge radius of drill bit, outer corner wear of drill bit, trust force, torque, delamination factor, and surface integrity characteristics, including borehole subsurface damage and diameter error of drilled hole, are presented and analyzed comparing dry drilling with cryogenic cooling of CFRP composite material. The findings demonstrate that cryogenic cooling has a profound effect on reducing the cutting edge rounding of drill bit and outer corner wear; it also helps enhancing the surface integrity characteristics of produced hole. However, cryogenic cooling generates larger thrust force, torque, and thus larger delamination factor.
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Cryogenic cooling-induced process performance and surface integrity in drilling CFRP composite material
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10.1007/s00170-015-7284-y
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2016-01-01
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Stratification or the creation of two convectively stable layers of liquids with different densities is the beginning of events leading to possible roll-over. The main factors are the convective mechanism whereby heat inflows into the lower layer become locked into that layer causing its temperature to rise and density to fall with time; also the preferential evaporation of methane from the upper layer of LNG (or propane from stratified LPG) will lead to an increase in density with time; also the heat of mixing is large and may evaporate up to 10 % of the liquid mixtures. The chapter discusses how stratification can be prevented, and/or removed, by adequate mixing operations. However, auto-stratification after filling is possible and needs to be countered by mixing at a later time. The chapter concludes with some advisory points towards anticipating roll-over, if the mixing is insufficient, or too late, to remove stratification.
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Factors Creating Stratification: Management of LNG Rollover
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10.1007/978-3-319-20696-7_6
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2016-01-01
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Drilling Drilling is the most commonly used manufacturing processes for holemaking. Researchers are dealing with the development of mathematical models Mathematical models for a series of phenomena related to drilling i.e. burr size, surface roughness, cutting forces. The present research investigates the relationships and parametric interaction of the three input variables (tool diameter, cutting velocity, feed rate) on the thrust force Thrust force and torque Torque developed during drilling of an Al7075 Al7075 workpiece with solid carbide tools. A complete set of experiments was performed and the response surface methodology (RSM) Response surface methodology (RSM) was used in order to acquire the mathematical models for both the thrust force and the torque required. The analysis of variance (ANOVA) was used to verify the adequacy of the mathematical models. The most significant factors were recognized. The main and interaction effects plots were studied and the 3D response surfaces are presented.
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Thrust Force and Torque Mathematical Models in Drilling of Al7075 Using the Response Surface Methodology
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10.1007/978-3-319-23838-8_6
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2016-01-01
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Twinning greatly affects the microstructure and mechanical performance of titanium alloys. The twinning behavior of a basal textured commercially pure titanium TA2 plates rolled to 4% reduction at the ambient and cryogenic temperatures has been investigated. Microstructures of the rolled samples were investigated by optical microscope (OM) and the twinning analysis was carried out based on orientation data collected by electron back-scatter diffraction (EBSD). {1122} contraction twins, {1124} contraction twins and {1012} extension twins have been observed. Twinning mode activity varied with rolling temperature. Twinning is considered as the dominant deformation mechanism during rolling at both temperatures for the strain condition. Larger proportion of grains activates twinning during cryorolling, and greater number and more diverse types of twins are observed; manifestly related to the suppression of dislocation slips at the cryogenic temperature. {1122} contraction twins are the dominate twin type within samples rolled at both temperatures. Several {1124} contraction twins are observed in the cryorolled sample while there are only a few in the sample rolled at room temperature. A few tiny {1012} twins have been identified in both samples. {1124} contraction twins are preferentially activated at cryogenic deformation temperature and the {1012} extension twins may result in local strain accommodation.
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Twinning Behavior of a Basal Textured Commercially Pure Titanium Alloy TA2 at Ambient and Cryogenic Temperatures
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10.1016/S1006-706X(16)30015-2
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2016-01-01
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Superconductive electrolytic niobium coatings 0.1–100 μm thick are prepared via electrochemical deposition onto SU-2000 glassy carbon substrates in (LiF + NaF + KF)_eut–K_2NbF_7 molten salt. Their structure, texture, and residual stresses are investigated by X-ray diffraction methods. It is shown that, when depositing the coatings, the diffusion superconductive layer of niobium carbide is formed at the substrate–coating interface. The sequence of changes in the axis of the texture of niobium coating from 〈100〉 through 〈211〉 to a textureless state with an increase in their thickness is established. It is found that, in the interval 0.5–5 μm, the sign of the stress changes (compressive stresses change into tensile stresses) and it reaches its maximum value. With an increase in the coating thickness from 5 to 100 μm, tensile stresses decrease from 345 to 80 MPa. It is shown that the coatings formed can be used as the material for creating a working layer of a superconducting cryogenic gyroscope rotor.
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Structure, texture, and properties of superconductive electrolytic niobium coatings on glassy carbon
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10.1134/S0031918X15110095
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2016-01-01
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All heat inflows are reduced as far as possible by using the correct insulations. This chapter is concerned with identifying all the A and B heat inflows, and how these can be reduced individually, or collectively, with suitable insulations. The first type, suitable for large tanks, is the gas-purged insulations such as perlite powder, fibreglass, plastic foams and rock wool. It is important that gas purged insulations totally fill the insulation space between inner and outer containers, with no holes or gaps. Any unfilled space will allow strong convection cells of purge gas to thermally short circuit the insulation. Ingress of water must also be excluded, because the water will freeze to ice, which has a high k value compared with the insulation. The second type, suitable for smaller tanks, is evacuated insulations. The latest versions are composed of multi-layer reflective insulation MLI with extremely low k values, provided the vacuum is maintained.
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Insulation: The Reduction of ‘A’ and ‘B’ Heat In-flows
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10.1007/978-3-319-20696-7_3
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2016-01-01
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Generally, many previous researches conducted using FBG sensors were based on the assumption that the coefficient of thermal expansion (CTE) and the thermo-optic coefficient (TOC) of FBG sensors are constants. However, they should be considered variables for higher accuracy when FBG sensors are applied to circumstances with temperature changes. In this paper, CTE and TOC of FBG sensors were precisely investigated from ambient room temperature (293 K) to cryogenic temperature (113 K). For this purpose, a new non-linear relationship between the wavelength shift and temperature change was proposed. From the test results, it was successfully investigated that the sum of CTE and TOC had a non-linear dependency on temperature changes and varied from 5.9×10^-6 /K (293 K) to 1.6×10^-6 /K (113 K).
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Thermal characteristics of FBG sensors at cryogenic temperatures for structural health monitoring
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10.1007/s12541-016-0001-4
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2016-01-01
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Poor corrosion resistance is limiting applications of Mg alloys. However, the corrosion performance of an Mg alloy can be enhanced through modification of its microstructure. It has been reported in the literature that the microstructure, especially grain size of AZ31 Mg alloy, has a significant influence on its corrosion resistance. In this study, AZ31B discs were subjected to a novel mechanical processing method-cryogenic burnishing; the surface of AZ31B work piece was burnished with a custom tool under a liquid nitrogen spraying condition. The processing led to a more than 3 mm thick surface layer with remarkably changed microstructures formed on the disc surface. Significant grain refinement occurred within this surface layer due to dynamic recrystallization induced by severe plastic deformation and effective cooling by liquid nitrogen. Both electrochemical method and hydrogen evolution method indicate that the corrosion resistance of the burnished surface was significantly improved.
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Cryogenic Burnishing of AZ31B Mg Alloy for Enhanced Corrosion Resistance
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10.1007/978-3-319-48223-1_95
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2016-01-01
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We calculate the parameters for the optimal design of a cryogenic system used to cool a HiPER laser target. The optimality criteria are minimum sliding time and maximum rolling time of the target in the system. The solution is obtained by simulating the motion of a spherical target through a curvilinear channel and constructing the set of criterion values and its Pareto boundary.
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Numerical Solution of the Two-Criterion Optimization Problem for the Shape of a Channel with a Moving Ball
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10.1007/s10598-015-9299-5
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2016-01-01
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In this article, we examine the problem of ensuring of ultrahigh precision for the cryogenic large space telescope (10 µm), its ultrahigh-precision pointing (one second of arc), and stabilization (0.2 of second of arc) in real time that must be dealt with. We suggest the novel concept design of the intelligence system of the active vibration protection and ultrahigh-precision pointing the cryogenic large space telescope of the observatory Millimetron aimed at addressing abovementioned problems.
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Intelligence System for Active Vibration Isolation and Pointing of Ultrahigh-Precision Large Space Structures in Real Time
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10.1007/978-3-319-27547-5_10
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2016-01-01
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This paper aims to develop the multi response optimization technique for predict and select the optimal setting of machining parameters while machining AISI 4340 steel using utility concept. The experimental studies in machining were carried out under varying conditions of process parameters, such as cutting speed (v), feed (f) and different cooling conditions (i.e. dry, wet and cryogenic in which liquid nitrogen used as a coolant) by using uncoated tungsten carbide insert tool. Experiments were carried out as per Taguchi’s L_9 orthogonal array with the utility concept and multi response optimization were performed for minimization of specific cutting force ( K _ S ) and surface roughness ( R _ a ). Further statistical analysis of variation (ANOVA) and analysis of mean (ANOM) were used to determine the effect of process parameters on responses K _ S and R _ a based on their P value and F value at 95 % confidence level. The optimization results proved that, cutting speed 57 m/min, feed 0.248 mm/min and cryogenic cooling is required for minimizes K _ S and R _ a .
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Optimizing Multi Characterstics in Machining of AISI 4340 Steel Using Taguchi’s Approach and Utility Concept
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10.1007/s40032-015-0201-1
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2016-01-01
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The transfer of cryogenic liquids like LNG down pipes is not as simple as pumping water. The difference is that cryogenic liquids are stored at their boiling points, whilst water is stored at ambient temperature, which is a long way from its boiling point at 100 °C. Pumping the boiling liquid can easily lead to much vapour generation, and 2-phase flow. The result is that the pumped mass flow reduces to a minimum or to zero. The simple way to stop this transfer disaster is to use pressure sub-cooling of the liquid.
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Liquid Transfers Avoiding 2-Phase Flow
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10.1007/978-3-319-20696-7_8
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2016-01-01
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In a cryogenic storage system, all the A heat inflows through the insulation, are into the stored liquid. The B heat inflows are absorbed by the “cold” in the boil-off vapour. They include heat transfer by radiation, conduction and convection from the ambient temperature environment of the storage system. The total A heat inflows are normally balanced by the latent heat of surface evaporation of the boil-off vapour the Boil-off Rate or BOR. There is no boiling as such in a cryogenic storage system. If some of the heat is stored by heating the liquid, the BOR will be reduced. This stored heat or ‘thermal overfill’, can with time lead to unstable rises in BOR to release the stored heat.
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Heat Flows in LNG and LPG Cryogenic Storage Systems at 1 Bar
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10.1007/978-3-319-20696-7_2
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2015-12-01
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The cooling down of cutting temperature in machining is very important for the improvement of tool life, especially when dealing with work materials that have low thermal conductivity such as titanium alloy. In this study designed to investigate the machining performance of a variety of cooling methods, cryogenic, Minimum quantity lubrication (MQL), and flood cooling are performed on solid end milling of titanium alloy, Ti-6Al-4V. In particular, the effect of internal and external spray methods on cryogenic machining is analyzed with a specially designed liquid nitrogen spraying system by evaluating tool wear and cutting force at cutting conditions. The cutting force is also analyzed for tool breakage detection. As a result, the combination of MQL and internal cryogenic cooling improves tool life by up to 32% compared to conventional cooling methods. The cutting force is also reduced significantly by this combination of cooling and lubrication strategy of side end milling.
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The effect of cryogenic cooling and minimum quantity lubrication on end milling of titanium alloy Ti-6Al-4V
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10.1007/s12206-015-1110-1
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2015-12-01
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The purpose of this paper is to investigate the effect of dynamic recovery on the mechanical properties of copper (Cu) during surface mechanical attrition treatment (SMAT) at both room temperature (RT) and cryogenic temperature (CT). Copper sheets were processed by SMAT at RT and at CT for 5, 15, and 30 min, respectively. The Cu samples after SMAT at RT for 30 min exhibited better ductility but lower strength than the samples after SMAT at CT for 30 min due to dynamic recovery. X-ray diffraction analysis indicated that decreasing temperature during SMAT led to an increase in the twin and dislocation densities. In addition, a thicker gradient structure layer with finer grains was obtained in the SMAT-processed Cu samples at CT than at RT. The results indicated that SMAT at CT can effectively suppress the occurring of dynamic recovery and produce ultrahigh strength pure copper without seriously sacrificing its ductility.
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Ultrahigh Strength Copper Obtained by Surface Mechanical Attrition Treatment at Cryogenic Temperature
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10.1007/s11665-015-1797-2
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2015-12-01
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Soil temperature regimes were studied in three ecosystems of the north of Western Siberia in the zone of isolated permafrost: the forest ecosystem with gleyic loamy sandy podzol (Stagnic Albic Podzol), the flat-topped peat mound ecosystem with humus-impregnated loamy sandy to light loamy peat cryozem (Histic Oxyaquic Turbic Cryosol (Arenic)), and the peat mound (palsa) ecosystem with oligotrophic destructive permafrost-affected peat soil (Cryic Histosol). Annual temperature measurements in the soil profiles demonstrated that these soils function under different temperature regimes: very cold permafrost regime and cold nonpermafrost regime. The following annual temperature characteristics proved to be informative for the studied soils: sums of above-zero temperatures at the depths of 10 and 20 cm, the maximum depth of penetration of temperatures above 10°C, and the number of days with daily soil temperatures above (or below) 0°C at the depth of 20 cm. On the studied territory, the insulating effect of the snow cover in winter was at least two times more pronounced than the insulating effect of the vegetation cover in summer. Cryogenic soils of the studied region are characterized by the high buffering towards changing climatic parameters. This is explained by the presence of the litter and peat horizons with a very low thermal diffusivity and by the presence of permafrost at a relatively shallow depth with temperature gradients preventing penetration of heat to the permafrost table.
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Temperature regimes of northern taiga soils in the isolated permafrost zone of Western Siberia
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10.1134/S1064229315100038
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2015-12-01
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We present the concept of and the procedure for realizing the primary scale of the spectral responsivity based on an absolute cryogenic radiometer at the Korea Research Institute of Standards and Science (KRISS). A detailed error and uncertainty analysis is performed by calibrating the standard detectors in the wavelength range from 300 nm to 1000 nm. The relative expanded uncertainty of the spectral responsivity calibration for a Si trap detector is 0.06% at 632.8 nm and 0.4% for other wavelengths ( k = 2). The calibration results are validated by comparing with the results from a theoretical model of quantum efficiency for a transmission-type trap detector.
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Realization of the spectral responsivity scale based on an absolute cryogenic radiometer
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10.3938/jkps.67.2045
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2015-12-01
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Titanium alloys are one of the most important design materials for the aircraft industry. The high strength-to-density-ratio and the compatibility with carbon fibre reinforced plastic are the reasons for a raising application in this field. The outstanding properties lead to challenging machining processes. High strength and low heat conductivity affect high mechanical and thermal loads for the cutting edge. Thus, the machining process is characterized by a rapid development of tool wear even at low cutting parameter. To reach a sufficient productivity it is necessary to dissipate the resulting heat from the cutting edge by a coolant. Therefore the cryogenic machining of two different titanium alloys is investigated in this work. The results point out the different behavior of the machining processes under cryogenic conditions because of the reduced thermal load for the cutting tool. According to this investigation, the cryogenic cooling with CO_2 enables an increase of the tool life in comparison to emulsion based cooling principles when machining the α+β-titanium alloy Ti-6Al-4V. The machining process of the high strength titanium alloy Ti-6Al-2Sn-4Zr-6Mo requires an additional lubrication realized by a minimum quantity lubrication (MQL) with oil. This combined cooling leads to a smoother chip underside and to slender shear bands between the different chip segments.
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Experimental investigation of tool wear and chip formation in cryogenic machining of titanium alloys
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10.1007/s40436-015-0122-5
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2015-12-01
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Clay swelling, an important phenomenon in natural systems, can dramatically affect the properties of soils and sediments. Of particular interest in low-salinity, saturated systems are osmotic hydrates, forms of smectite in which the layer separation greatly exceeds the thickness of a single smectite layer due to the intercalation of water. In situ X-ray diffraction (XRD) studies have shown a strong link between ionic strength and average interlayer spacing in osmotic hydrates but also indicate the presence of structural disorder that has not been fully described. In the present study the structural state of expanded smectite in sodium chloride solutions was investigated by combining very low electron dose, high-resolution cryogenic-transmission electron microscopy observations with XRD experiments. Wyoming smectite (SWy-2) was embedded in vitreous ice to evaluate clay structure in aqua . Lattice-fringe images showed that smectite equilibrated in aqueous, low-ionic-strength solutions, exists as individual smectite layers, osmotic hydrates composed of parallel layers, as well as disordered layer conformations. No evidence was found here for edge-to-sheet attractions, but significant variability in interlayer spacing was observed. Whether this variation could be explained by a dependence of the magnitude of long-range cohesive (van der Waals) forces on the number of layers in a smectite particle was investigated here. Calculations of the Hamaker constant for layer-layer interactions showed that van der Waals forces may span at least five layers plus the intervening water and confirmed that forces vary with layer number. Drying of the disordered osmotic hydrates induced re-aggregation of the smectite to form particles that exhibited coherent scattering domains. Clay disaggregation and restacking may be considered as an example of oriented attachment, with the unusual distinction that it may be cycled repeatedly by changing solution conditions.
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Formation and Restacking of Disordered Smectite Osmotic Hydrates
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10.1346/CCMN.2015.0630602
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2015-11-14
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Background The effect of the holding time of the deep cryogenic treatment on the strain hardening of HY-TUF, a low-alloy medium-carbon steel, and a comparison with strain hardening of conventional heat-treated steel were investigated. Methods For this purpose, a deep cryogenic treatment was done for different holding times of 12, 24, 48, and 72 h. The metallographic results indicate completion of martensitic transformation; η-carbide precipitation and decrement of carbon concentration in martensitic matrix happened while carrying out a deep cryogenic process. Results Observations of transmission electron microscopy indicate higher density of dislocations within martensite near the cementite compared to that near the η-carbides. The tensile flow stress data for this steel was examined in terms of Hollomon equation. The results show that strain hardening of conventional heat-treated steel takes place in two stages. Conclusions This evidence is related to the co-deformation of austenite and martensite. The strain hardening takes place in one stage for the deep cryogenic-treated steels, and their strain hardening exponents increase (from ~0.29 to 0.47) with an increasing holding time up to 48 h. A further increase in the holding time of the deep cryogenic treatment is found not to vary strain hardening exponent. The increase of strain hardening exponent and then observation of plateau in this parameter show an optimum value for the holding time of the deep cryogenic treatment (48 h).
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Influence of the holding time of the deep cryogenic treatment on the strain hardening behavior of HY-TUF steel
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10.1186/s40712-015-0052-9
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2015-11-01
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The results of experimental studies using SuperOx J-PI-12-20Ag-20Cu tape superconductors in developing capsule carriers for cryogenic systems of noncontact transport of targets for IFE are presented.
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On the use of the second-generation HTSC tapes in cryogenic transport systems for IFE targets
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10.3103/S1068335615110019
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2015-11-01
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A grinding experiment was conducted with Ti-6Al-4V alloy in a wet and cryogenic coolant environment. An electroplated cubic boron nitride grinding wheel was used for this experiment. The input process parameters that were considered were depth of cut and nozzle inclination angle. The output response parameters that were considered were tangential forces, normal forces, grinding zone temperature, specific energy, and surface roughness (R_a). Experimental results indicate an 8% to 27% reduction in tangential force and 3% to 12% reduction in normal force when liquid nitrogen was used as coolant. R_a is reduced by a maximum of 38% over wet grinding, and grinding zone temperature is reduced by up to 55%. Surface modification and chip morphology were analyzed. Experimental results indicated that the nozzle angle at 45° has a significant effect on the grinding process.
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Grinding titanium Ti-6Al-4V alloy with electroplated cubic boron nitride wheel under cryogenic cooling
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10.1007/s12206-015-1036-7
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2015-11-01
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In this study, a number of wear and tensile tests were performed to elucidate the effects of deep cryogenic treatment on the wear behavior and mechanical properties (hardness and tensile strength) of AISI H13 tool steel. In accordance with this purpose, three different heat treatments (conventional heat treatment (CHT), deep cryogenic treatment (DCT), and deep cryogenic treatment and tempering (DCTT)) were applied to tool steel samples. DCT and DCTT samples were held in nitrogen gas at −145 °C for 24 h. Wear tests were conducted on a dry pin-on-disk device using two loads of 60 and 80 N, two sliding velocities of 0.8 and 1 m/s, and a wear distance of 1000 m. All test results showed that DCT improved the adhesive wear resistance and mechanical properties of AISI H13 steel. The formation of small-sized and uniformly distributed carbide particles and the transformation of retained austenite to martensite played an important role in the improvements in the wear resistance and mechanical properties. After cleavage fracture, the surfaces of all samples were characterized by the cracking of primary carbides, while the DCT and DCTT samples displayed microvoid formation by decohesion of the fine carbides precipitated during the cryo-tempering process.
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Effects of Deep Cryogenic Treatment on the Wear Resistance and Mechanical Properties of AISI H13 Hot-Work Tool Steel
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10.1007/s11665-015-1712-x
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2015-10-01
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Successful employment of advanced tool steel in engineering applications is related to its ability in terms of meeting service life requirements and fabrication with proper dimensions. Deep cryogenic treatment may be used to produce advanced tool steel by simultaneously increasing toughness, strength, and hardness. Twelve sets of specimens were tested, 9 of which were deep cryogenic treated and then tempered. The best results, 12–35 % improvement in tensile toughness, 9–16 % improvement in hardness, and 28–36 % improvement in tensile strength were obtained.
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Optimization of Tensile Properties of AISI S1 Tool Steel
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10.1007/s12666-015-0510-3
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2015-10-01
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This experimental work was carried out by turning of AISI 1040 medium carbon steel in which the effect of cryogenic cooling (LN_2) used as a cutting fluid is compared to that of dry machining with respect to tool wear i.e. crater and flank wear, surface roughness, cutting forces (feed and cutting forces) and cutting temperature. Experiments were performed using uncoated tungsten carbide insert tool having various feed rate and constant cutting speed. Compared to dry machining, in LN_2 machining, overall the tool wear were reduced to 55.45 and 65.53 %, surface roughness was reduced to 125.90 % and forces were reduced to 61.94 and 96.60 %. The experimental results proved that the application of cryogenic coolant overall increases the machining performance as compared to dry machining.
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Experimental Investigation of Machining AISI 1040 Medium Carbon Steel Under Cryogenic Machining: A Comparison with Dry Machining
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10.1007/s40032-015-0178-9
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2015-10-01
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Cryogenic machining opens up new industrial perspectives in difficult-to-cut materials like nickel-based alloys. In particular, drilling is an operation that generates high thermal and mechanical loading to the drill. Therefore, tool performance, hole geometry and surface integrity can be highly affected. The objective of this study is to analyse tool performance during drilling of IN718 using conventional metal working fluids (MWF) and cryogenic cooling conditions, and correlate it with the thermo-mechanical phenomena. This study is conducted with standard coated cemented carbide twist drills, designed to work with MWF. The results show that drill performance under cryogenic cooling is strongly affected by its geometry. The axial force, drilling torque and tool wear/failure are higher under cryogenic cooling when compared to conventional MWF. Therefore, in order to take advantage of the cryogenic machining, new drill design is required, which currently is not available on the market.
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Thermo-mechanical effects in drilling using metal working fluids and cryogenic cooling and their impact in tool performance
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10.1007/s11740-015-0619-6
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2015-10-01
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Hydrodynamic processes occurring when cryogenic liquid is injected into water are experimentally investigated. Processes accompanying the phase transitions under these conditions were recorded. Optical recording of the processes revealed their structure and stages. It is shown that at the outer boundary of a cylindrical vapor bulb, active turbulent mixing is observed, which should be taken into account when one will develop a mathematical model of the process. At the gas–water interface, ice crystal structures were observed. The obtained results may be useful for studying a new method of gas hydrate production based on the shock-wave technique.
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Visualization of physical processes occurring on liquid nitrogen injection into water
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10.1134/S1810232815040037
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2015-10-01
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Hybrid cutting process combines different physical mechanism to achieve an extended performance of the cutting process. Yet, adding supporting systems and consumptions must be seen critical because they are not directly adding value, which means that they are consumers only. It is essential to analyse and optimize their use in relation to the superior process development. Thereby the two physical mechanisms and their interactions result in many parameters to be handling for successful process setup. Different approaches, e.g. design of experiments or finite elements methods, exist to analysis and optimize such complex machining processes. Both approaches will be shown by analysis of drilling with cryogenic cooling and laser-assisted milling. Finally, a new combined methodology will be presented in general.
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Methodology for analysing hybrid cutting processes with thermal assistance
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10.1007/s11740-015-0624-9
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2015-10-01
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Wet cutting is the most common cooling method used during the cutting of titanium alloys. However, this method is associated with high costs, pollution, and hazards to operators. Minimal quantity lubrication (MQL) is an effective environmentally friendly cooling method, but is not suitable for difficult-to-machine materials because of its low heat transfer capacity. Using cryogenic air mixed with MQL (CAMQL) for cooling has better heat transfer, but high equipment costs and noise pollution limit its industrial application. This paper proposes the use of oils on water (OoW) as a cooling method for the turning of Ti-6Al-4V alloy and aims at exploring the effect of OoW cooling. Both external oils on water (EOoW) and internal oils on water (IOoW) methods are considered. The effects of EOoW spraying location and the amount of water required for IOoW are compared with respect to chip morphology, cutting temperatures, cutting forces, surface roughness, and tool wear. The use of CAMQL at different air temperatures is compared with wet and dry cutting. The results show that the chips created by OoW and CAMQL are continuous spirals. Compared with CAMQL, use of IOoW cooling with an appropriate amount of water or EOoW cooling from a proper location yields lower surface roughness and slower flank wear rate, and bare areas on the cutting tool substrate were absent because of better lubrication. The properties of the lubricants have an influence on IOoW and CAMQL, but not on EOoW. A suitable cutting tool coating should be selected to ensure the best cutting performance under these cooling methods.
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Tool wear in Ti-6Al-4V alloy turning under oils on water cooling comparing with cryogenic air mixed with minimal quantity lubrication
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10.1007/s00170-015-7062-x
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2015-09-01
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Titanium alloys, mainly because of their poor thermal conductivity, need to be cut at relatively low cutting speeds, with obvious negative consequences on the profitability of machining. An important amount of research has been done in order to increase productivity in titanium machining operations: high performance coatings and innovative technologies to improve insert resistance to wear represent promising solutions. In this work, a highly performing cutting insert (coated with a TiAlN layer obtained by Physical Vapor Deposition (PVD) magnetron sputtering) has been tested against the option of applying a Deep Cryogenic Treatment (DCT), when used for rough turning of aerospace titanium. The effects of the DCT have been experimentally investigated with two different experimental plans at low and high cutting speeds (respectively v_c ≤ 50 m/min, v_c ≥ 60 m/min). Statistical analyses of the results have been performed. The results show that at low cutting speed, the DCT treatment does not increase the tool life. At higher values of v_c, flank wear vs. time curves of coated tools have been determined, with and without DCT, and they clearly show that cryogenically treated tools present better wear resistance at higher cutting speeds. The wear mechanisms on the rake face and the flank for these two TiAlN coated tools have been analysed using a scanning electron microscope. The adhesion of titanium on the tool surface is lower for a DCT treated insert. The results indicate that the hardening of tools induced by the cryogenic treatment improves their useful life in high rate machining of titanium.
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Wear behaviour of PVD coated and cryogenically treated tools for Ti-6Al-4V turning
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10.1007/s12289-014-1215-6
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2015-09-01
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The effect of filler type and mass percentage on the properties of low-density rigid polyurethane foams at a temperature of 77K was investigated. The mechanical properties of foams of density 55-90 kg/m^3 filled with milled carbon fibers of average length of 100 and 60 μm and hollow glass microspheres of average diameter of 65 μm were compared. A considerable increase in the compressive elastic modulus in the foam rise direction with increasing filler content was observed. The compression strength of the foams in the parallel and perpendicular directions at the cryogenic temperature decreased upon introducing the milled carbon fibers of either type. The compression strength of the foams of density 90 kg/m^3 somewhat increased only upon introducing the glass microspheres.
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Effect of Filler Type on the Properties of Rigid Polyurethane Foams at a Cryogenic Temperature
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10.1007/s11029-015-9516-5
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2015-09-01
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Investigations were conducted on the machining of AISI D2 tool steel via Conventional electrical discharge machining (CEDM) and Cryogenic cooled electrode in electrical discharge machining (CCEDM). Machining parameters, including discharge current, pulse on time, and gap voltage, were varied to investigate their effects on machining performance such as on Electrode wear ratio (EWR), surface roughness (Ra), microstructure, surface morphology, and elemental composition. Experimental results showed that EWR was reduced by 20% in CCEDM compared with in CEDM. Moreover, the Ra in CCEDM decreased by approximately 19% compared with that in CEDM. The results also indicated that the surface morphology of the workpiece machined via CCEDM was better than that of the workpiece machined via CEDM. Lastly, the damaged layer and microcracks were less in the workpiece machined via CCEDM than those in the workpiece machined via CEDM.
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Experimental investigation of the process parameters in cryogenic cooled electrode in EDM
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10.1007/s12206-015-0832-4
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2015-09-01
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In this study, the effects of deep cryogenic treatment (DCT) on the mechanical and tribological properties of AISI D3 tool steel were investigated together with a systematic correlation between their hardness and wear resistance. It was found that conventionally heat treated AISI D3 tool steel samples were significantly hardened via an additional DCT, which was attributed to the more retained austenite elimination, more homogenized carbide distribution and more reduction in carbide size in the samples. As a result, the hardened AISI D3 samples exhibited reductions in their friction and wear during rubbing against alumina and 100Cr6 steel balls under different normal loads due to the effectively hindered removal of surface materials. The results clearly showed that the DCT was an effective way to improve the mechanical and tribological properties of the AISI D3 tool steel samples as the tribological performance of the tool steel samples was significantly influenced by their hardness.
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Effects of deep cryogenic treatment on mechanical and tribological properties of AISI D3 tool steel
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10.1007/s40544-015-0089-z
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2015-09-01
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We present a theoretical study of ignition thresholds and combustion efficiencies of fusion fuels in the form of solid chemical compounds of hydrogen isotopes with light elements that can be used in inertial confinement fusion targets without cryogenic devices required in traditional deuterium–tritium (DT) ice fuel designs.
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Ignition Thresholds and Combustion Efficiencies of Non-Cryogenic ICF Targets
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10.1007/s10946-015-9518-8
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2015-09-01
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After 27 years of storage in liquid nitrogen, we managed to restore the growth of suspension cell culture of alfalfa ( Medicago sativa L.). The influence of factors affecting viability of alfalfa cells in vitro was investigated together with cytogenetic and physiological characteristics after their storage at the temperature of liquid nitrogen (−196°C). As a result of freezing/thawing, approximately 80% of predominantly polyploid cells died, and osmotic stress was the main injurious agent. Thus, after cryogenic storage, cell culture mainly consisted of hypo and hyper haploid and hypo and hyper diploid cells. After 35 growth cycles, the restored population reached a dynamic equilibrium between the cells of different levels of ploidy with modal class (accounting for more than 50%) of polyploid cells. The strain under investigation is notable for a high activity of peroxidase (PO). After cryogenic storage, PO activity considerably decreased; however, during 35 growth cycles, enzyme activity gradually rose to the level characteristic of original cell culture prior to freezing. In order to protect the cells from endogenous ice nucleation, we used cryoprotector dimethyl sulfoxide (DMSO). It was found that DMSO was not efficient at a concentration of 7% for cell protection against osmotic stress and exerted a moderate antiradical influence in respect to superoxide anion but improved viability of recovered cells and affected activity of PO and aldehyde reductase and the level of lipid peroxidation.
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Recovery of cytogenetic and physiological characteristics of a population of alfalfa cells after cryogenic storage
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10.1134/S1021443715040172
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2015-08-01
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In the last decades, many superconductor-based devices have been utilized in practical applications that refer to the production/sensing of ultra-high/low magnetic fields, resistive storage of data, etc. The superconducting magnetoresistance effect (sMRE) observed in ferromagnetic/superconducting/ferromagnetic trilayers (TLs) has been widely studied in the literature. Here, we investigate Ni_80Fe_20/Nb/Ni_80Fe_20 and Co/Nb/Co TLs on a comparative basis and we provide technical guidelines that empower us to design magnetic field sensors and magnetic field-controlled supercurrent switches for cryogenic applications. The performance of these TLs has been studied in great detail. It turned out that Ni_80Fe_20-based TLs are applicable in the regime of low magnetic fields (on the order of a few hundred Oe) due to their magnetically soft character, while Co-based ones are effective at relatively higher magnetic fields (on the order of a few thousand Oe) owing to their magnetically harder behavior. The Ni_80Fe_20-based TLs exhibit a sMRE magnitude, (R_max − R_min)/ R_nor ×100 %, on the order of 30–50 % and a field sensitivity, d R ( H )/d H , on the order of 4.0–6.0 mOhm/Oe. The Co-based TLs have higher sMRE magnitude on the order of 30–100 %; however, they exhibit lower field sensitivity on the order of 0.3–0.6 mOhm/Oe. Finally, the Co-based TLs exhibit an abnormal behavior of the upper critical field line, H_c2( T ), at low magnetic fields. This feature is absent in the Ni_80Fe_20-based TLs. Due to the differences outlined above, the Ni_80Fe_20-based and Co-based TLs can be possibly utilized in two distinct categories of devices, namely magnetic field sensors and magnetic field-controlled supercurrent switches, respectively.
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Cryogenic Magnetic Field Sensors and Magnetic Field-Controlled Supercurrent Switches Based on Ferromagnetic/Superconducting/Ferromagnetic Trilayers: the Performance of NiFe/Nb/NiFe and Co/Nb/Co
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10.1007/s10948-015-3047-0
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2015-08-01
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The triple-point temperature of neon, $$T_{\mathrm{tp-Ne}}$$ T tp - Ne , is known to have dependence on the isotopic composition. Recently, the Technical Annex for the International Temperature Scale of 1990 was updated to specify the method of correction for the isotopic reference ratio of neon. In this study, to confirm this correction in the Technical Annex independently, the effects of the isotopic composition of neon on $$T_{\mathrm{tp-Ne}}$$ T tp - Ne for three commercial neon gas sources were studied. For the measurement of the isotopic composition, a gas mass spectrometer was used to compare the sample gases with a reference neon gas whose isotopic composition was known with high precision by a gravimetric method. For the measurement of $$T_{\mathrm{tp-Ne}}$$ T tp - Ne , an open-cell type cryostat for the realization of low-temperature fixed points was used. The physical cell and the thermal environment around it remained very similar for all $$T_{\mathrm{tp-Ne}}$$ T tp - Ne measurements with the neon gases due to the nature of the open-cell type system. Therefore, the difference in $$T_{\mathrm{tp-Ne}}$$ T tp - Ne among different samples could be measured with a relatively low uncertainty, canceling many systematic effects that are common to all measurements. Our result was consistent with the correction in the Technical Annex. Furthermore, because one of the commercial neon gases was the bottle that was used for KRISS measurements in the international comparison CCT-K2, it is now possible to correct the measurement for the reference isotopic ratio and compare it with other measurements for which isotopic composition data are available.
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Triple-Point Temperature and the Isotopic Composition of Three Commercial Neon Gases
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10.1007/s10765-015-1883-6
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2015-08-01
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Poly-tetrafluoroethylene (PTFE) is a high performance engineering polymer generally used as a coating material. PTFE shows poor wear resistance, thus in order to improve the wear resistance of PTFE, cryogenic treatment (CT) has proved to be the most effective technique. The improvement in wear performance of PTFE on CT at −185 °C for 12 h has been conclusively established whereas, its effectivity on PTFE-mica composite coating is not yet studied. Thus in the present investigation the suitable parameters of CT for PTFE composite coating are established. In addition to this, the wear behaviour and mechanism of different types of PTFE composite coatings, popularly used in non-stick cookware is also studied in a comparative manner as before and after CT. The wear performance of the composite is found to be enhanced.
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To Investigate the Wear Mechanism on Cryogenic Treatment of PTFE-Mica Filled Composite Coatings in Cookware
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10.1007/s12666-014-0491-7
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2015-07-01
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A set of technologies and prototype systems for eco-friendly shutdown of the power-generating, process, capacitive, and transport equipment is offered. The following technologies are regarded as core technologies for the complex: cryogenic technology nitrogen for displacement of hydrogen from the cooling circuit of turbine generators, cryo blasting of the power units by dioxide granules, preservation of the shutdown power units by dehydrated air, and dismantling and severing of equipment and structural materials of power units. Four prototype systems for eco-friendly shutdown of the power units may be built on the basis of selected technologies: Multimode nitrogen cryogenic system with four subsystems, cryo blasting system with CO_2 granules for thermal-mechanical and electrical equipment of power units, and compressionless air-drainage systems for drying and storage of the shutdown power units and cryo-gas system for general severing of the steam-turbine power units. Results of the research and pilot and demonstration tests of the operational units of the considered technological systems allow applying the proposed technologies and systems in the prototype systems for shutdown of the power-generating, process, capacitive, and transport equipment.
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Complex of technologies and prototype systems for eco-friendly shutdown of the power-generating, process, capacitive, and transport equipment
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10.1134/S0040601515070095
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2015-07-01
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Cryogenic-based machining has been drawing attention for machining hard metals and super alloys such as the titanium alloys due to environmental concerns and growing regulations over pollution. In this study, cryogenic-assisted milling of Ti–6Al–4V has been performed with the preheated workpiece methods to avoid the cryogenic hardening by liquid nitrogen (LN_2). Preliminary experiments show an increase in the cutting force due to cooling of the workpiece; therefore, workpiece preheating was adopted to increase the workpiece temperature. Three cutting speeds and three machining environments (dry, cryogenic, and cryogenic plus preheated) were considered in the analysis of tool wear, cutting forces, tool wear morphology, and chip morphology. Soft (Si coating) and hard (CrTiAlN)-coated tools were used in this study. It was observed that the tool life was increased by 50 to 90 % for Si-coated tools and 50 to 55 % for CrTiAlN-coated tools. The tool wear morphology showed that rubbing and chipping were the primary tool wear mechanisms. It is expected that the present work will be useful for improving tool life and reducing the cost of hard metal products. It may also be useful for reducing the ecological problems by conventional cutting fluids.
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Tool life improvement in cryogenic cooled milling of the preheated Ti–6Al–4V
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10.1007/s00170-015-6849-0
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2015-07-01
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This paper presents the effects of process parameters like cutting speed, feed rate and different cooling conditions (i.e. dry, wet and liquid nitrogen used as a coolant) on tool wear (crater and flank wear) in machining of EN24 alloy steel using uncoated tungsten carbide insert tool. Experiments were carried out as per Taguchi’s L9 orthogonal array and further statistical analysis of variation (ANOVA) was used to study the effect of process parameters on responses i.e. crater wear and flank wear, based on their P value and F-value at 95 % confidence level. Overall, cryogenic cooling provides improved tool life leading to extended product life and performance. Mathematical models for crater and flank wear are found to be statistically significant.
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Modelling and Optimization of Tool Wear in Machining of EN24 Steel Using Taguchi Approach
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10.1007/s40032-015-0175-z
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2015-07-01
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The Moffatt-Swern oxidation (MSO) is a multistep, versatile, metal-free reaction by which alcohols are transformed into aldehydes and ketones. Batch MSO requires low temperatures (−70 °C) due to a highly exothermic reaction step that generates intermediates. This work shows that a rigorous investigation of the MSO in batch can be used as a stepping-stone to its implementation in a continuous-flow reactor (CFR). This work has two parts: the first part details the investigation of MSO in batch; the second covers the translation of the knowledge derived from batch to a CFR. The MSO batch reaction was performed under cryogenic conditions with real-time process monitoring. The reaction was monitored with Raman spectroscopy and could be tracked throughout the reaction. All concentrations were validated using offline high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS). Two configurations of the CFR were produced. Configuration 1 used the traditional batch methodology in terms of reagent addition and reaction conditions. Configuration 2 used the information derived from the batch reaction, changing the order of the reagent addition and increasing the temperature of the reactor. Real-time quantitative monitoring of chemical yield in the CFR was demonstrated via Raman spectroscopy and partial least squares (PLS) regression modeling. Reaction yield was accurately predicted every 15 s, reducing the need for chromatographic validation once the model was built. Configuration 2 was shown to perform comparably to configuration 1 at low temperature and far outperforming it at higher temperatures. Both CFR configurations performed significantly better than the batch setup in terms of temperature and yield, as was expected.
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Moffat-Swern Oxidation of Alcohols: Translating a Batch Reaction to a Continuous-Flow Reaction
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10.1556/1846.2015.00025
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2015-07-01
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The grinding process is crucial for the production of fine surfaces and the intense heat induced during the grinding operation affects the surface and sub-surface of the work material. The coolant plays a crucial role in the efficiency of the grinding process by controlling the temperature at the wheel and work material interface. In this study, the use of liquid nitrogen (LN_2) as a cryogenic coolant was investigated as a method of reducing the surface roughness, surface modifications and chip morphology. The grinding wheel manufactured by the sol–gel (SG) technique and a conventional aluminum oxide (Al_2O_3) wheel were used for the experiment. The experimental result of cryogenic cooling was compared with those of dry and wet cooling. The grinding operation performed on the AISI D3 steel with cryogenic cooling generated a reduction of 48–62 % over dry grinding and 34–51 % over the conventional coolant, when the surface roughness was considered. Cryogenic cooling under SG wheel delivered an enhanced surface quality. The increased delivery pressure of the LN_2 further improved the grinding performance.
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Surface modifications in grinding AISI D3 steel using cryogenic cooling
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10.1007/s40430-014-0241-0
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2015-06-01
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PtSb_2 is a potential material for cryogenic Peltier cooling applications because of its semimetal character with a high Seebeck coefficient and low electrical resistivity. To investigate the effects of n -type doping we studied PtSb_2− x Te_ x with x between 0 and 0.04. A clear doping effect was observed, and the power factor was maximized for samples with x = 0.005, 0.02, and 0.04. If thermal conductivity reduction techniques can be used, this material may be a promising candidate for cryogenic Peltier cooling applications.
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Low-Temperature Thermoelectric Properties of PtSb_2−x
Te_
x
for Cryogenic Peltier Cooling Applications
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10.1007/s11664-014-3480-z
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2015-06-01
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The aerospace industry has increasingly been using materials that have outstanding mechanical properties such as high strength, thermal and chemical resistance. Inconel 718 has been considered ideal material for hot and corrosive environments like aircraft jetengines. However, Inconel is difficult to machine due to its high toughness, low thermal conductivity and work-hardening during cutting. In this regard, the cutting speed for Inconel cannot be higher because tool chipping, notching and excessive wear occur at high cutting speeds. In this study, machining methods such as minimum quantity lubrication (MQL) with and without nano-particles, and cryogenic treated cutting tools have been applied for Inconel machining. Tool wear in these conditions are analyzed and compared with that of traditional machining methods, dry and wet machining. Coated and uncoated carbide tools are used to evaluate the coating effect associated with the machining methods. From the experimental results, surprisingly, the dry and wet machining outperformed both MQL and MQL with nano-particles in terms of tool wear. The cryogenic treated tool showed stable tool wear without severe edge fracture due to cryogenic hardening of the cutting tool while the MQL and Nano-MQL fractured severely, and the uncoated carbide tool performed better than the coated one.
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Tool wear analysis on coated and uncoated carbide tools in inconel machining
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10.1007/s12541-015-0215-x
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2015-06-01
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NIST SRM 1548a Typical Diet has a certified iodine mass fraction value of 0.759 mg kg^−1, with a rather large expanded uncertainty (relative value 13.6 %). This might be due to the iodine inhomogeneous distribution in the pooled food material. We have proven that cryogenic grinding of NIST SRM 1548a (at the temperature of liquid nitrogen) yields a free-flowing material, with the standard deviation due to a random inhomogeneity that is lower (by a factor of 3) compared with the original material. We have also proven that no change in the certified iodine value and no contamination with other elements present (even at the sub-µg kg^−1 level) occurred during the cryogenic grinding process. Thus, we have obtained a quality control material that sets up more stringent requirements on the validation and quality control procedures of the measurement of iodine mass fraction in complex food matrices.
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Improving iodine homogeneity in NIST SRM 1548a Typical Diet by cryogenic grinding
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10.1007/s00769-015-1134-3
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2015-06-01
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The elastic properties of new piezoelectric Sr_3NbGa_3Si_2O_14 crystals of the langasite (lanthanum gallium silicate) family have been investigated. The temperature dependences of the elastic constants C _11, C _33, C _66, and C _44 have been measured in a wide temperature range from 300 to 4.2 K. The characteristic parameters of the crystal associated with the Einstein temperature and the Grüneisen parameter have been estimated at cryogenic temperatures. It has been shown that the piezoelectric activity of the crystal remains almost unchanged with a decrease in temperature from 300 to 4.2 K.
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Low-temperature elastic properties of Sr_3NbGa_3Si_2O_14 single crystals
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10.1134/S1063783415060311
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2015-06-01
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Static tensile and bending experiments are conducted on 3D MWK carbon/epoxy composites with two types of fiber architecture at room and cryogenic temperature (low as −196 ℃). Macro-Fracture morphology and SEM micrographs are examined to understand the deformation and failure mechanism. The results show that tensile stress vs. strain curves have linear elastic feature up to failure; while the load-deflection curves for composites with large fiber orientation angle have pronounced nonlinear and failure in steps. Meanwhile, tensile and bending properties at liquid nitrogen temperature have been improved significantly. Moreover, the properties can be affected greatly by the fiber architecture and these decrease with increasing fiber orientation angle at room and cryogenic temperatures. The results also show the damage and failure patterns of composites vary with the fiber architecture and temperature. The main failure for material A is 0 ° fibers fracture and matrix cracking. The failure mechanism for material B is the delamination, 90 °/+45 °/−45 ° fiber/matrix interface debonding and fibers tearing, as well as 0 ° fibers’ breakage. At cryogenic temperature, the matrix is solidified and the interfacial adhesion between fibers and matrix is enhanced significantly. However, the brittle failure becomes more obvious, more microcracks propagate and interpenetrate.
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Mechanical response and failure of 3D MWK carbon/epoxy composites at cryogenic temperature
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10.1007/s12221-015-1349-2
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2015-06-01
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This paper analyzes how a deep cryogenic process changes the microstructure and mechanical properties of a medium-carbon low-alloy steel. The light microscopy, microhardness testing, and transmission electron microscopy reveal that η-carbide and martensite are constituent phases of deep cryogenic treated (DCT) steel, while the microstructure of conventional heat-treated (CHT) steel consists of cementite, martensite, and retained austenite. Transmission electron microscopy also shows that the particles of η-carbide have the shape of ultra-fine globules in DCT martensite. The η-carbides grow in a Hirotsu and Nagakura orientation relationship to the martensitic matrix that enables highly coherent interphase boundaries. The results of the mechanical tests, including tensile and Charpy impact tests, show that the deep cryogenic process can improve toughness in terms of elongation (~12.81%), tensile fracture energy (~266 MPa), and the ductile–brittle transition temperature (~−17.2 °C). The results of fractography are also consistent with the improvement in toughness. It is also found that the strength and macrohardness values are increased. Unlike CHT steel, discontinuous yielding is observed in DCT steel. Moreover, there is no change in Young’s modulus due to the deep cryogenic treatment.
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Effect of Deep Cryogenic Treatment on the Microstructure and Mechanical Properties of HY-TUF Steel
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10.1007/s13632-015-0206-4
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2015-06-01
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Enhancing the performance of cutting tools is an important factor in reducing production costs. Cutting tools are subjected to processes such as heat treatment and coating in order to improve their performance. Cryogenic treatment, which is also known as sub-zero heat treatment, has made significant contributions to the improvement of wear resistance, tool life, dimensional integrity, and product quality of cutting tools. The mode of application of cryogenic treatment and the type of cutting tool both affect tool performance. Therefore, it is necessary to examine the way cryogenic treatment is applied to cutting tools and its effects on their performance. This study reviews the literature on the performance of cryo-treated cutting tools.
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A review of cryogenic treatment on cutting tools
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10.1007/s00170-014-6755-x
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2015-06-01
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The main low temperature detectors (LTD) applications and results of LTD in fundamental physics will be considered with particular reference to the nuclear and subnuclear fields. The results obtained with cryogenic techniques and in particularly those with the hybrid ones where bolometers are operated in coincidence or anticoincidence with scintillation or semiconductor detectors will be reported and discussed. In particular the paper will refer to the results and plans in the direct determination of the neutrino mass. In connection with this subject we will review the already obtained and planned results of experiments on neutrinoless double beta decay to reveal the possible violation of the lepton number with the consequent determination or constraint on the neutrino mass. The present and future impact of low temperature techniques in direct detection of Weakly Interacting Massive Particles will be discussed in comparison with the present and future experiments with “classical” detectors. The report will be concluded by the present few and hopefully more numerous future results on the application of low temperature detectors on rare events in low energy nuclear physics.
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Application of Low Temperature Detectors in Physics: Yesterday, Today, Tomorrow
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10.1007/s10909-014-1118-4
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2015-05-01
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An integrated method for enhancing energy efficiency of modern large-scale cryogenic complexes (annual energy consumption more than 100 GWh) that allow operation of superconducting magnets of particle accelerators is analyzed. Two conventional loops, namely, “cold” and “warm” (compressor), with subsequent separate optimization of each loop, are marked out in the cryogenic complex cycle. Separate optimization helps simplify the choice of optimal cycle pressure as well as the choice of the most efficient helium vapor evacuation for providing the required cryogenic temperature of 2 K.
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Cost Optimization in Designing Modern Cryogenic Complexes of Large Superconductor Systems
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10.1007/s10556-015-9992-4
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2015-05-01
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Cryogenic two-phase flow with phase change heat transfer, consisting of a saturated liquid slug translating in its own superheated vapor in a circular pipe, was numerically simulated. The cryogenic chill down process was simplified by assuming ideal inverted annular flow regime. The method used is based on a sharp interface concept and developed on an Eulerian Cartesian fixed-grid with a cut-cell scheme and marker points to track the moving interface. The unsteady, axisymmetric Navier–Stokes equations in both liquid and vapor phases are solved separately and used to compute the velocity, pressure, and temperature fields and the deformation of the liquid core very accurately. Three most common cryogenic fluids, viz. nitrogen, oxygen, and argon were included in the study. The influence of non-dimensional parameters like Reynolds number $$Re,$$ R e , Weber number $$We$$ W e , and Jakob number $$Ja$$ J a on flow characteristics was studied by systematically varying only one at a time. $$Re$$ R e was found to affect the mass flow rates, but did not have a significant influence on the wall cooling or the Nusselt number. $$We$$ W e affected the interface shape at the leading edge of the liquid slug, also influencing the heat transfer and velocity field there. $$Ja$$ J a affects all three quantities of interest, i.e., mass flow rate, wall cooling, and the Nusselt number.
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A Direct Numerical Simulation of Axisymmetric Cryogenic Chill Down in a Pipe in Microgravity
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10.1007/s10909-014-1257-7
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2015-05-01
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The effect of deep cryogenic treatment on the formation of reversed austenite (RA) in super martensitic stainless steel was investigated. RA was found to form in steels without (A) and with (B) deep cryogenic treatment. The volume fraction of RA initially increased and then decreased with increasing tempering temperature over 550–750 °C for the two steels, which were quenched at 1050 °C. In addition, for both with and without deep cryogenic treatment, the RA content reached a maximum value at 650 °C although the RA content in steel B was greater than that in steel A over the entire range of tempering temperatures. Furthermore, the hardness (HRC) of steel B was greater than that of steel A at tempering temperatures of 550–750 °C. From these results, the basic mechanism for the formation of RA in steels A and B was determined to be Ni diffusion. However, there were more Ni-enriched points, a lower degree of enrichment, and a shorter diffusion path in steel B. It needed to be noted that the shapes of the RA consisted of blocks and stripes in both steels. These shapes resulted because the RA redissolved and transformed to martensite along the martensitic lath boundaries when the tempering temperature was 650–750 °C, and a portion of RA in the martensitic lath divided the originally wider martensitic laths into a number of thinner ones. Interestingly, the RA redissolved more rapidly in steel B and consequently resulted in a stronger refining effect.
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Effect of deep cryogenic treatment on formation of reversed austenite in super martensitic stainless steel
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10.1016/S1006-706X(15)30026-1
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2015-05-01
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The S-N fatigue behavior of Fe15Mn (Fe-0.7C-15Mn-2Al) austenitic steel, including base metal and butt-welded joint, was investigated at 298 K and 110 K, and the results were compared to those of STS304L (Fe-1Si-2Mn- 20Cr-10Ni) counterparts. Both specimens showed improved resistance to S-N fatigue with decreasing temperature from 298 K to 110 K. The resistance to S-N fatigue of Fe15Mn steel was greater at 298 K, while it was lower at 110 K, than STS304L steel. Unlike STS304L, Fe15Mn steel did not show any notable transformation induced plasticity and twining-induced plasticity effect under fatigue loading at ambient and cryogenic temperatures. The S-N fatigue behavior of Fe15Mn steel was strongly dependent on tensile strength at both ambient and cryogenic temperatures. Similar S-N fatigue behavior was also observed for the butt-welded joints of Fe15Mn steel. The S-N fatigue behavior of Fe15Mn steel and its weld was discussed based on the fractographic and microscopic observations.
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Ambient and cryogenic S-N fatigue behavior of Fe15Mn steel and its weld
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10.1007/s12540-015-4397-7
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2015-05-01
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The effect of current pulses and deep freezing down to a temperature of 77 K on the bending strength of cutting hard-alloy plates was investigated. The efficiency of different conditions of their modification was verified.
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Effect of Electric Current Pulses and Cryogenic Temperatures on the Strength of Cutting Hard-Alloy Plates
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10.1007/s11223-015-9674-7
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2015-04-01
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In this study, the effects of cryogenic treatment and drilling parameters on surface and hole quality were investigated in the drilling of AISI 304 stainless steel under dry drilling conditions. The control factors to provide better surface roughness ( Ra ) and roundness error ( Re ) were determined using the Taguchi method. RSM was also used to determine interactions among the control factors. In addition, analysis of variance was employed to determine the most significant control factors on the surface roughness and roundness error. Three drill categories (conventional heat treatment—CHT, cryogenic treatment—CT, cryo-tempering—CTT), cutting speeds, and feed rates were considered as control factors, and an $$\text{ L }_{27}$$ L 27 full factorial design with a mixed orthogonal array was selected for experimental trials. As a result, it was found that the feed rate and cutting speed were the most significant factors on the surface roughness and roundness error with percentage contributions of 83.07 and 64.365 % respectively. The predictive quadratic models were derived by the RSM to obtain the optimal surface roughness and roundness error as a function of drilling parameters and heat treatments applied to the drills.
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Optimization of drilling parameters using Taguchi technique and response surface methodology (RSM) in drilling of AISI 304 steel with cryogenically treated HSS drills
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10.1007/s10845-013-0783-5
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2015-04-01
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The charpy impact experiments on the 3D integrated woven spacer composites with six types of core heights are performed at room and liquid nitrogen temperatures (as low as −196 °C). Macro-fracture morphology and SEM micrographs are examined to understand the deformation and failure mechanism. The results show that the impact energy increase with the increase of the core height at both room and liquid nitrogen temperatures. Meanwhile, the impact properties at liquid nitrogen temperature have been improved significantly than that at room temperature. Moreover, at room temperature, the penetration fracture of the face sheets, the tearing and pulling out of the core fibers as well as the cracking of the matrix is the main damage and failure patterns. However, at liquid nitrogen temperature, the matrix crushing dominates the failure. Less fibers fracture and brittle fracture feature becomes more obvious. In addition, with the increase of the core heights, the damage of composites has been reduced significantly at room and liquid nitrogen temperatures.
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Experimental study on the charpy impact failure of 3D integrated woven spacer composite at room and liquid nitrogen temperature
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10.1007/s12221-015-0875-2
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2015-04-01
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In-process cryogenic cooling has been credited with more precise products and enhanced integrity of machined surfaces. Enhanced surface integrity properties include smoother and more precise surfaces, grain refinement, and increase in surface hardness. This paper reports on the effect of liquid nitrogen (LN) cryogenic cooling and cutting parameters on surface hardness of drilled holes in magnesium alloy AZ31B. Drilling experiments of in-process cryogenic cooling were conducted while measuring thrust force and torque. Surface microhardness (HV) values and grain structure at drilled hole surfaces were measured. Finite element analysis (FEM) and model for simulating this cryogenically cooled drilling operation was developed. Numerical output of the state variables strain, strain rate, and temperature were used to predict Zener–Hollomon parameter ( Z -parameter) values at the surfaces of the holes. Using an expression that relates Z -parameter to grain size, average values of the latter were estimated. Surface hardness values were also estimated from a Hall–Petch-like relation. Cryogenic cooling was found to have a pronounced effect in increasing surface hardness. Experimental measurements of grain size and hardness values compare favorably with the numerical results of the FEM model. In-process application of cryogenic cooling resulted in improved surface hardness of drilled holes as compared with those drilled while dry.
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An experimental and numerical study of the effect of cryogenic cooling on the surface integrity of drilled holes in AZ31B Mg alloy
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10.1007/s00170-014-6650-5
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2015-03-01
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A design of the low-temperature chamber, embedded into the cuvette compartment of the LOMO-Spektr SF-56 spectrophotometer, is described. The chamber is intended for studying absorption spectra of colloidal nanoparticles of metals in neutral cryogenic liquids.
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A low-temperature chamber for recording optical absorption spectra of colloidal nanoparticles of metals in cryogenic liquids
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10.1134/S0020441215020098
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2015-03-01
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The general expression of the interaction potential between electrons in a plasma-like medium (gas plasma, semiconductor plasma) with degenerate electrons (light negative charge carriers) is calculated. It is shown that the electron-electron interaction at short distances (smaller than or of the order of the Debye screening length) is described by the ordinary Coulomb potential with Debye field screening. At distances far exceeding the Debye screening length, the electron repulsion weakens and attraction becomes dominant, which is caused by the wave interaction of electrons due to the ion-acoustic wave exchange. It is shown that the wave interaction potential decreases with distance as 1/ r ^3. The possibility of forming the bound state of two electrons (Cooper pair) in the field of such a potential in indicated media is discussed.
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Wave interaction of electrons in cryogenic plasma-like medium with degenerate electrons
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10.3103/S106833561503001X
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2015-03-01
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Microstructure in subsurface is investigated to understand the effect of cryogenic coolant in hard machining of hardened AISI 52100 bearing steel. The cutting experiments were performed under dry and cryogenic cooling conditions using cubic boron nitride (CBN) tool inserts. The change in the microstructure was analyzed at varying of the tool shape and cutting speed for different initial hardness of the workpiece. The machined surfaces and subsurface were analyzed by several investigation techniques. The affected layer depth was observed with a scanning electron microscope (SEM), while the phase composition was analyzed by X-ray diffraction (XRD). The grain size has been directly measured with a focused ion beam and scanning ion microscope (FIB-SIM) and compared with an indirect method of analysis: X-ray diffraction peak profile (XDPP). The experimental results show that the microstructural phase strongly depends on the cutting process parameters. Furthermore, when the cryogenic cooling is applied, martensitic structure disappears in some cases. The grain size on the machined surfaces is also influenced by the material properties and the process parameters. In addition, it is demonstrated that the XDPP indirect method for grain size analysis is a valid alternative to the direct method.
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Evaluation of microstructural changes by X-ray diffraction peak profile and focused ion beam/scanning ion microscope analysis
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10.1007/s00170-014-6471-6
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2015-03-01
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Composite macroporous poly(vinyl alcohol) (PVA) cryogels have been prepared by cryogenic treatment (freezing at −20°C for 12 h followed by defrosting at a rate of 0.03°C/min) of dispersions of chitosan particles swollen in an aqueous 120 g/L PVA solution. The elasticity moduli and fusion temperatures have been determined for corresponding samples, and their microstructure has been investigated by optical microscopic examination of their thin sections. The rigidity and heat endurance of the PVA-chitosan composite cryogels have been shown to increase with filler concentration. In addition, the rheological properties of initial dispersions have been studied and the appearance of adhesion contacts between discrete and continuous phases has been revealed already at the stage of dispersion preparation. The optical microscopic investigations of the morphological features of the initial dispersions and the microstructure of the composites have established a relatively uniform distribution of filler particles in the bulk of composite cryogels. It has been shown that chitosan particles incorporated into the matrix of the macroporous PVA cryogel are capable of sorbing heavy metal ions—in particular, bivalent copper ions—from aqueous solutions.
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A study of cryostructuring of a polymer system. 39. Poly(vinyl alcohol) composite cryogels filled with chitosan microparticles
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10.1134/S1061933X1502012X
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2015-03-01
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Since 1992, the largest Russian cryogenic helium complex of the superconducting accelerator Nuclotron with the cooling capacity of 4000 W at 4.5 K has been operating at the Joint Institute for Nuclear Research in Dubna. The construction of this high-efficient cryogenic system included a large number of technical ideas that had never been applied before in the world. The helium complex of the Nuclotron has become the most advanced and largest Russian liquid helium plant consisting of two KGU–1600/4.5 units, which are capable to operate for a common collector of the liquid helium delivery to the consumer and provide the total capacity of 1000 l/h. In 1992 its use allowed one to begin for the first time the export of liquid helium by means of 40 m^3 auto transport containers. The annual level of export deliveries reached 1 million liters. In the near future it is planned to construct a new accelerator complex comprising beside the Nuclotron a superconducting booster and collider to provide collisions of high-intensity beams of heavy ions up to gold Au^+79. The cryogenic system of this megaproject includes the latest Russian developments: helium liquefiers with the capacity of 1100 l/h and screw helium compressor aggregates with the outlet pressure of 3 MPa and capacity of 6600 Nm^3/h. The assembling and tests of pilot units are being carried out at present. This equipment being commissioned to mass production may lay the foundation for the technology of industrial liquefaction of helium for the development of new deposits in Eastern Siberia.
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Liquid Helium Technologies at the Cryogenic Complex of the Heavy Ion Collider NICA
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10.1007/s10948-014-2653-6
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2015-03-01
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The main achievements of the investigations into cryogenic dusty plasma and the review of the state of the studies carried out in this region are presented. The peculiarities of the cryogenic plasma of gas discharges that affect the processes of self-organization of dusty plasma structures are discussed. The investigation of cryogenic dusty plasma is shown to be promising for uses in fundamental or applied physics, including application to nanotechnologies.
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Synergetics of dusty plasma and technological aspects of the application of cryogenic dusty plasma
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10.3103/S106837551502012X
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2015-03-01
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The influence of injection conditions on rocket engine combustion stability is investigated for a sub-scale combustion chamber with shear coaxial injection elements and the propellant combination hydrogen–oxygen. The experimental results presented are from a series of tests conducted at subcritical and supercritical pressures for oxygen and for both ambient and cryogenic temperature hydrogen. The stability of the system is characterised by the root mean squared amplitude of dynamic combustion chamber pressure in the upper part of the acoustic spectrum relevant for high frequency combustion instabilities. Results are presented for both unforced and externally forced combustion chamber configurations. It was found that, for both the unforced and externally forced configurations, the injection velocity had the strongest influence on combustion chamber stability. Through the use of multivariate linear regression the influence of hydrogen injection temperature and hydrogen injection mass flow rate were best able to explain the variance in stability for dependence on injection velocity ratio. For unforced tests turbulent jet noise from injection was found to dominate the energy content of the signal. For the externally forced configuration a non-linear regression model was better able to predict the variance, suggesting the influence of non-linear behaviour. The response of the system to variation of injection conditions was found to be small; suggesting that the combustion chamber investigated in the experiment is highly stable.
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Characterisation of acoustic energy content in an experimental combustion chamber with and without external forcing
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10.1007/s12567-015-0079-z
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2015-03-01
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The effects of the deep cryogenic heat treatment on the microstructural changes, wear resistance, and hardness of carburized DIN 1.7131 grade steel were investigated. Results show that cryogenic heat treatment reduced the retained austenite and increased the carbide amount. In addition, after the cryogenic heat treatment, carbide shows a more uniform distribution, as compared to the conventionally treated ones. It was also clarified that the hardness of the cryogenically treated samples was improved, but the relative improvement decreases with the distance as the surface increases. It has been shown that the wear resistance improves due to the cryogenic heat treatment, and the predominant wear mechanism is a combination of the adhesive and tribo-chemical wear.
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Effect of Deep Cryogenic Heat Treatment on the Wear Behavior of Carburized DIN 1.7131 Grade Steel
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10.1007/s40195-015-0204-1
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2015-02-01
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The authors presented practical fabricated specifications of a prototype 10kW class high-temperature superconductor (HTS) direct current (DC) induction heating machine and analyzed its operational characteristics including the system’s efficiency and the temperature distribution of the aluminum billet in detail In this paper, we discussed the fabrication process and focused particularly on the practical operating results of the HTS DC induction heating machine. The major operating characteristics of the HTS magnet under each stage were analyzed in detail. Detailed efficiency was investigated through the measuring of the realtime motor input and the billet temperature. Through a monitoring system, critical parameters were measured in real-time operation. The total heating time to 500 ^∘C of the billet’s temperature was 400 s at 0.25 T at the center of the billet. These research outcomes are expected to be useful for the commercial design of a large-scale 2G HTS DC induction furnace for industrial fields.
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Fabrication and Testing of a Prototype 10-kW Class HTS DC Induction Heating Machine
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10.1007/s10948-014-2759-x
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2015-02-01
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In the development of hightemperature superconducting (HTS) power machines, it is necessary to develop the HTS termination. The HTS termination system is composed of a conductor, insulating material and electrical insulation at cryogenic temperature. In particular, the insulation body with sheds and electrical insulation at cryogenic temperature has attracted a great deal of interest from the aspects of the size, weight and efficiency of termination. In this paper, we investigate the surface discharge characteristics on the shed and insulation body against glass-fiber reinforced plastics (GFRP) in liquid nitrogen (LN_2). The surface discharge characteristics of GFRP in LN_2 were successfully performed according to directions of glass-fiber, diameter, length, width and height.
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A Study on the Insulation of the Termination for HTS Cable in Liquid Nitrogen
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10.1007/s10948-014-2731-9
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