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2015-02-01
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An experiment to investigate the natural circulation of cryogenic liquid has been performed. The study is motivated mainly by our recent development of cryogenic cooling system for prototype superconducting cyclotron without any circulating pump. In the natural circulation loop system, a cooling channel is attached on the outer surface of the aluminum block and the liquid nitrogen passes through inside of the channel to cool the block indirectly. A cryocooler as a heat sink is located at the top to recondense cryogenic vapor coming from the aluminum block in which electrical heater is installed as a heat source. The main dimensions are determined using the relevant analysis, and the natural circulation loop is successfully fabricated. The temperature distributions in the loop are measured during initial cool-down process and in steady state, from which the modified Grashof numbers are calculated and compared with the existing correlation estimated with one-dimensional analysis for steady state flow.
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Natural Circulation Flow of Cryogenic Liquid for Superconducting Magnet Applications
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10.1007/s10948-014-2743-5
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2015-02-01
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Hypothermic hydration graft storage is essential to reduce the metabolic demand of cells in vitro . The alleviated metabolic demands reduce the emergence rate of anaerobic metabolism generating adenosine triphosphate (ATP) energy that creates free radicals. The excessive free radicals can damage cells and tissues due to their highly oxidative power with molecules. Current cooling systems such as a conventional air cooling system and an ice pack system are inappropriate for chilling cell tissues in vitro because of inconvenience in use and inconsistent temperature sustainability caused by large size and progressive melting, respectively. Here, we develop a medical chilling device (MCD) for hypothermic hydration graft storage based on thermo-hydrodynamic modeling and thermal electric cooling technology. Our analysis of obtained hydrodynamic thermal behavior of the MCD revealed that the hypothermic condition of 4°C was continuously maintained, which increased the survival rates of cells in vitro test by reduced free radicals. The validated performance of the MCD promises future development of an optimal hypothermic hydration graft storage system designed for clinical use.
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Medical chilling device designed for hypothermic hydration graft storage system: Design, thermohydrodynamic modeling, and preliminary testing
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10.1007/s12206-015-0117-y
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2015-02-01
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The effects of variable cryogenic temperature on the thermal expansion are measured by tensile method for several commercial superconducting composite wires of NbTi/Cu, Nb_3Sn/Cu, and high-temperature superconducting (HTS) Bi2212/Ag tapes. A variable temperature cryostat system is constructed to provide successive cooling environment from 300 to 77 K, and a cryogenic-type extensometer is utilized to measure the deformation of the superconducting wires arising from tensile and thermal loadings. In comparison with the mechanical deformation at room temperature, the corresponding thermal deformation at the variable cryogenic temperature is recorded and evaluated during stretching of the superconducting wires. The thermal expansion behavior of the composite wires and superconductor filaments is further captured. It shows that the thermal expansion of NbTi/Cu composite wire, NbTi filaments, Nb_3Sn/Cu composite wires, and Nb_3Sn filaments is almost linearly dependent upon the temperature, while those of HTS Bi2212/Ag tapes exhibit notable nonlinear features during cooling of the superconducting wires. In addition, based on the thermal expansion measured from room temperature to liquid nitrogen temperature, the thermal expansions at 4.2 K are extrapolated for low-temperature composite wires and their filaments, which are compared with the experiments using thermal methods in the existing literature. The results indicate that our variable temperature cryostat system and corresponding tensile method will be an easy way for measuring the thermal parameter of superconducting composite wires.
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Measurement of Thermal Expansion of Superconducting Wires at Cryogenic Temperature Based on Tensile Method
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10.1007/s10948-014-2762-2
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2015-01-13
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We report on thin film deposition by matrix-assisted pulsed laser evaporation of simple hydroxyapatite (HA) or silver (Ag) doped HA combined with the natural biopolymer organosolv lignin (Lig) (Ag:HA–Lig). Solid cryogenic target of aqueous dispersions of Ag:HA–Lig composite and its counterpart without silver (HA–Lig) were prepared for evaporation using a KrF* excimer laser source. The expulsed material was assembled onto TiO_2/Ti substrata or silicon wafers and subjected to physical–chemical investigations. Smooth, uniform films adherent to substratum were observed. The chemical analyses confirmed the presence of the HA components, but also evidenced traces of Ag and Lig. Deposited HA was Ca deficient, which is indicative of a film with increased solubility. Recorded X-ray Diffraction patterns were characteristic for amorphous films. Lig presence in thin films was undoubtedly proved by both X-ray Photoelectron and Fourier Transform Infra-Red Spectroscopy analyses. The microbiological evaluation showed that the newly assembled surfaces exhibited an inhibitory activity both on the initial steps of biofilm forming, and on mature bacterial and fungal biofilm development. The intensity of the anti-biofilm activity was positively influenced by the presence of the Lig and/or Ag, in the case of Staphylococcus aureus , Pseudomonas aeruginosa and Candida famata biofilms. The obtained surfaces exhibited a low cytotoxicity toward human mesenchymal stem cells, being therefore promising candidates for fabricating implantable biomaterials with increased biocompatibility and resistance to microbial colonization and further biofilm development.
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Structural and biological evaluation of lignin addition to simple and silver-doped hydroxyapatite thin films synthesized by matrix-assisted pulsed laser evaporation
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10.1007/s10856-014-5333-y
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2015-01-01
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Considering its size, Georgia has a large number of glaciers. In the mountains of Georgia, there are about 786 registered glaciers, with a total area of about 550 km. About 82.5 % are in the upper courses of the Kodori, Inguri, Rioni, and Tereck rivers. For the past 150 years, significant glacier retreat (0.8–1.7 km) and shrinking of their area by 16 % has been observed. Since the middle of the 1940s, the glaciological situation has been characterized by a sharp reduction in the glacial area, but with the simultaneous increase in their number as glaciers disintegrated into separate smaller ones, although at the same time separate movements have also taken place. Avalanches are common in Georgia. Nearly 340 inhabited places are under the threat of avalanche attacks. About 31 % of the territory of Georgia is subject to avalanches (18 % in eastern and 13 % in western Georgia). This chapter discusses glacial processes and their impacts.
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Glacial and Periglacial Processes
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10.1007/978-3-319-05413-1_9
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2015-01-01
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Understanding of local mechanisms chip forming during machining by removal of material is difficult, to this end; a cutting finite element modelling is required. This study aims initially to model orthogonal cutting of Ti17 titanium alloy in dry and cryogenic machining and in a second time to study the influence of the application of cryogen during machining on temperature fields and cutting forces in numerical simulation. An experimental study was also conducted to determine the mode of tool wear and the evolution of flank wear.
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Numerical and Experimental Approach in Assisted Cryogenic Machining
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10.1007/978-3-319-17527-0_10
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2015-01-01
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Transmission soft x-ray microscopy (SXM) is an important new technique for visualizing and quantifying biological specimens, especially individual cells. In SXM the specimen is illuminated with “water-window” soft x-rays (i.e., x-ray photons with energies in the range 284–543 eV). As the illuminating light passes through the specimen, it is attenuated more strongly by carbon- and nitrogen-containing biomolecules than by water. Consequently, even subtle differences in molecular composition produce SXM images with quantitative contrast. In this chapter, we will discuss the basic concepts behind SXM and describe how 2D SXM data is used to calculate high fidelity 3D soft x-ray tomographic (SXT) reconstructions of the specimen. SXT offers many advantages over other high-resolution imaging methods. A particular strength is the capacity to image intact, fully hydrated cells, including eukaryotes such as yeast or mammalian cells. In addition to standalone use, SXT data can be integrated with data from other imaging modalities. The recent development of cryogenic confocal fluorescence tomography (CFT) has permitted 3D SXT reconstructions to be combined directly with 3D molecular localization data measured from the same cryopreserved specimen. With the advent of correlated CFT-SXT imaging, cell biologists can now accurately locate the position of specific molecules in the context of a high-resolution reconstruction of a near-native state cell.
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Putting Molecules in the Picture: Using Correlated Light Microscopy and Soft X-ray Tomography to Study Cells
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10.1007/978-3-319-04507-8_43-1
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2015-01-01
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Polymeric Coatings to Fight Biofouling
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10.1007/978-3-642-36199-9_366-1
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2015-01-01
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A heat pipe is defined as a device that utilizes the evaporation heat transfer in its evaporator and the condensation heat transfer in its condenser, in which the vapor flow from the evaporator to condenser is caused by the vapor pressure difference, and the liquid flow from the condenser to the evaporator is produced by capillary force, gravitational force, and/or other forces directly acting on it.The conventional heat pipe basically is referred to as a heat pipe driven by capillary force as shown in Fig. 9.1. A typical conventional heat pipe consists of three sections: an evaporator or heat addition section, an adiabatic section, and a condenser or heat rejection section. When heat is added to the evaporator section of the heat pipe, the heat is transferred through the shell and reaches the liquid. When the liquid in the evaporator section receives enough thermal energy, the liquid vaporizes. The vapor carries the thermal energy through the adiabatic section to the condenser section, where the vapor is condensed into the liquid and releases the latent heat of vaporization. The condensate is pumped back from the condenser to the evaporator by the driving force acting on the liquid.
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Conventional Heat Pipes
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10.1007/978-1-4939-2504-9_9
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2015-01-01
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The effects of in-process cryogenic LN cooling on the resulting grain size of the friction stir processing (FSP) of twin roll cast (TRC) magnesium alloy AZ31B. Sheets (3 mm-thick) of TRC AZ31B were friction stir processed using a wide range of processing parameters (mostly tool feed and spindle speed). The tool rotational speed was varied between 600 RPM and 2,000 RPM while the tool feed rate varied between 75 mm/min and 900 mm/min. Thrust force and torque values were experimentally measured using a 4-component dynamometer. Temperature measurements were monitored during the different tests using Infrared sensors and thermocouples. The microstructure of processed samples was observed using optical microscopy. It was found that thrust force and torque values of the pre-cooled samples were 5% higher than those of the room temperature samples due to the material hardening induced by the cooling effect. Finer and more homogenous microstructure was observed for the pre-cooled samples when compared with samples processed at room temperature. The average grain size of pre-cooled samples was predicted using a relation -previously introduced by the authors- that relate grain size and the Zener-Hollomon parameter for TRC AZ31B. This equation was found to correctly predict grain diameter for in-line cooled FSP AZ31B samples at temperatures lower than room temperature.
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Pre-cooling Effects on the Resulting Grain Size in Friction Stir Processing of AZ31B
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10.1007/978-94-017-9804-4_24
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2015-01-01
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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 thawing at a rate of 0.03°C/min) of mixtures of an aqueous PVA solution and poly(butadiene- co -styrene) latex. The values of the elasticity modulus and fusion temperature have been determined for the obtained samples, and their microstructures have been studied by optical microscopy of thin sections. The rigidity and heat endurance of the filled cryogels have been shown to markedly increase with the fraction of the latex in the initial liquid disperse system. Moreover, it has been found that, beginning from some critical concentration of the latex in a mixture with the initial PVA solution, cryostructuring leads to the formation of two interpenetrating phases—a continuous phase of the hydrophilic PVA cryogel and a network of the hydrophobic phase that results from cryocoagulation of non-frost-resistant poly(butadiene- co -styrene) latex. The morphological features of this phase have been studied, and the sizes of macropores and the thicknesses of their walls have been determined with the help of scanning electron microscopy.
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A study of cryostructuring of polymer systems. 37. Composite cryogels formed from dispersions of poly(butadiene-co-styrene) latex in aqueous poly(vinyl alcohol) solution
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10.1134/S1061933X15010111
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2015-01-01
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This chapter first discusses the challenges with the tool material selection for machining of high-silicon aluminum-matrix composites. It is shown that the combination of a soft easy-to-adhere Al-matrix and highly abrasive particles limits the use of cemented carbide tools due to high rate of adhesion and abrasion wear. The issue becomes intolerable in high-speed machining applications. As a result, polycrystalline diamond (PCD) is slowly becoming a material of choice for such applications. The chapter presents the major research advances in PCD as a tool material. The wear mechanism of PCD is discussed at macro- and micro levels. A discussion on the need and a report on the progress in the development of thermal stable grades of PCD conclude the chapter.
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Polycrystalline Diamond (PCD) Tool Material: Emerging Applications, Problems, and Possible Solutions
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10.1007/978-3-662-45088-8_1
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2015-01-01
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Inconel 718 is widely used in sophisticated engineering applications due to its unique properties such as high oxidation resistance and corrosion resistance even at high temperatures and retains a mechanical strength under these conditions as well. But machining such an exotic material is costly due to the rapid tool wear. An attempt has been made to improve the performance of cemented tungsten carbide (WC-Co, K20) tool through various posttreatments namely cryogenic treatment and controlled heating and oil quenching. The treated tools were evaluated for their properties through microhardness and X-ray diffraction technique (XRD). The treated tools were subjected to machining (turning) of difficult-to-cut material, i.e., superalloy Inconel 718 to check their performance enhancement. Results showed that post-treated tools performed better while machining (turning) of superalloy Inconel 718 indicating that selected posttreatments can be potential posttreatment methods for improving machining ability of cemented tungsten carbide tools.
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Effect of posttreatments on the performance of tungsten carbide (K20) tool while machining (turning) of Inconel 718
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10.1007/s00170-014-6279-4
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2015-01-01
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Microspectral analysis was used to identify the molecular components of a number of plant and animal cells. This technique makes it possible to perform optical measurements during freezing to the temperature of liquid nitrogen. The revealed biochemical heterogeneity suggests functional specialization of individual cells within a population. Fluorescence quenching analysis revealed temperature intervals in which the processes of recrystallization of intracellular water associated with specific pigment-protein complexes take place. The proposed experimental approach may find application in modern correlation microscopy and in cryobiology in searching for the optimal freezing and thawing regimes of various cells for cryopreservation of genetic material.
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Spectral measurements of the functional heterogeneity of cells and their organelles
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10.1134/S0006350915010030
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2015-01-01
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The effects of cutting speed in cryogenic and dry machining on the surface integrity characteristics (the affected layer, microhardness, transformation response, transformation temperature, and latent heat for transformation) of NiTi shape memory alloys are investigated. It has been found that the cutting speed has remarkable effects on the surface and subsurface properties of machined NiTi alloys. Increased cutting speed results in decreased subsurface hardness and increased latent heat for phase transformation. In general, the depth of affected layers decreases with increased cutting speed in dry and cryogenic machining. Chips show a similar behavior as affected layer in terms of transformation response and microhardness. Cryogenic machining is found to have greater effects on the surface and subsurface properties of the machined work material in comparison with dry machining at all given cutting speeds.
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Cutting Speed Dependent Microstructure and Transformation Behavior of NiTi Alloy in Dry and Cryogenic Machining
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10.1007/s11665-014-1247-6
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2015-01-01
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Membrane-based gas separation (GS) systems are today widely accepted and, in some cases, used as unit operations for generation, separation, and purification of gases in gas, chemical, petroleum, and allied industries. There are several fields of application of membrane GS, and several membrane materials and membrane modular solutions are available today for the various fields of interest. However, the growth of large-scale industrial applications for GS is still far from reaching the real potential this technology offers. Together with the investigation of new materials with improved properties, a key component for widespread use of this technology is a better understanding and utilization of the unit operations already available on the market in integrated membrane systems, combining various membrane operations in industrial processes. The role of membrane engineering is crucial to overcome this hurdle.
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Application of Gas Separation Membranes
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10.1007/978-3-319-01095-3_6
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2015-01-01
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An analysis of CO_2 emissions and soil microbiological activity has been performed in larch stands of different ages that developed on cryogenic soils and represent different stages of post-fire succession. An abrupt increase in the soil emissions of CO_2 (by more than 2 times) in young stands (15–30 years old), as well as a decrease of soil-respiration rate at the later stages of pyrogenic successions because of the restoration of the moss-lichen cover and the closure of the stand canopy was seen. Intraseasonal and interannual variations of soil CO_2 fluxes were also revealed; however, their dynamics was largely determined by the local conditions.
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Dynamics of soil respiration at different stages of pyrogenic restoration succession with different-aged burns in Evenkia as an example
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10.1134/S1067413615010117
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2015-01-01
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Air, oxygen and nitrogen are examples of environmental friendly lubricants in the gaseous state. Even at low pressures, they have strong influences on the cutting performance. However, as the cutting speed increases, the effectiveness of the gas lubricants attenuated. This has conventionally been attributed to the reduction in interface penetration and thus of intimate contact and adhesion between chip and tool. This chapter also provides a review of the advanced techniques supplying gaseous and vapours capable of prolonging tool life at high cutting speeds.
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Utilisation of Environmental Friendly Gaseous and Vapour in Machining
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10.1007/978-981-287-266-1_4
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2015-01-01
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This paper made an experimental investigation of cage instability in respect to cage pocket designs, ball-pocket clearances, and flow rate in cryogenic environment. Test bearing bore size is 70 mm deep groove ball bearing. Cage pocket designs are circular and elliptical, and ball-pocket clearances are 0.6, 1.2, 1.8 mm. Test is operating at 6000 rpm during 1500 s in liquid nitrogen. As a several criterions of wear and stability for cryogenic ball bearing, we measured a friction coefficient of bearing and sound vibration FFT were measured and analyzed to predict failure mechanism of bearing elements. From these results, predicted and diagnosed with sound properties of cage, inner/outer race and balls. These works will be assessed more stable with optimum ball-pocket clearance and elliptical pocket design bearing in sufficient coolant.
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Correlation Between Friction Coefficient and Sound Characteristics for Cage Instability of Cryogenic Deep Groove Ball Bearings
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10.1007/978-3-319-06590-8_159
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2015-01-01
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In the present paper the constitutive model of dissipative material at cryogenic temperature is presented. Three coupled dissipative phenomena: plastic flow, plastic strain induced phase transformation and evolution of damage are considered using a thermodynamically consistent framework. The theory relies on notion of local state, and involves one state potential for the writing of the state laws, and dissipation potential for the description of the irreversible part of the model. The kinetic laws for state variables are derived from the generalized normality rule applied to the plastic potential, while the consistency multiplier is obtained from the consistency condition applied to the yield function. The model is applied for simulation of two distinct dissipative phenomena taking place in FCC metals and alloys at low temperatures: plastic strain induced transformation from the parent austenitic phase to the secondary martensitic phase, and evolution of micro-damage.
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Constitutive Modeling of Dissipative Phenomena in Austenitic Metastable Steels at Cryogenic Temperatures
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10.1007/978-3-319-14660-7_3
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2015-01-01
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Effect of cryogenic grinding on volatile oil, oleoresin content, total phenolics, flavonoid content and anti-oxidant properties of seed extract of nine coriander ( Coriandrum sativum L.) genotypes have been analyzed. Volatile oil and oleoresin content was significantly high in cryogenically ground samples ranged from 0.14 % in genotype RCr 436 to 0.39 % in genotype Sindhu while oleoresin content was ranged from 13.80 % in ACr 1 to 19.58 % in Australia. Yield of methanol crude seed extract was invariably high in cryo ground samples of all the genotypes and total phenolic content was also high in all the genotypes. It was ranging from a minimum of 32.44 mg in RCr 41 to a maximum of 92.99 mg Gallic Acid Equivalent (GAE)/g crude seed extract in genotype Sindhu. Similarly Total flavanoid content was also increase in all cryogenically ground samples and ranged from 15.28 mg Quercetin Equivalent (QE)/g crude seed extract in genotype Sindhu to 20.85 mg QE/g crude seed extract in genotype Swati. Methanol crude seed extract of all genotypes were evaluated for its antioxidant activity in terms of total antioxidant content, 1, 1-Diphenyl-2-picrylhydrazin (DPPH) free radical scavenging % and EC_50 value. The amount of total antioxidant content in cryo ground seeds was significantly high in all genotypes which was ranging from 5.09 mg in genotype Sindhu to 10.85 mg Butyl Hydroxyl Toluene (BHT) Equivalent/g crude seed extract in genotype Sadhna. DPPH scavenging % was invariably more in cryo ground seeds in all the genotypes. Higher concentration of antioxidant content and DPPH scavenging % suggested high antioxidant activity in cryo ground samples. It could be concluded that cryogenic grinding technology is able to retain flavour and antioxidant properties of coriander irrespective of the genotypes.
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Effect of cryogenic grinding on volatile oil, oleoresin content and anti-oxidant properties of coriander (Coriandrum sativum L.) genotypes
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10.1007/s13197-013-1004-0
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2015-01-01
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Cryopreservation technologies have opened the door to the possibility of long-term storage of valuable biodiverse germplasm of many plant species. However, for successful conservation by cryopreservation Cryopreservation , a large amount of work is still needed. This chapter describes the role of plants belonging to the family Gentianaceae in improving our understanding of cryopreservation. Emphasis is on expected problems and benefits originated from enhancing embryogenic capacity by osmotic dehydration Osmotic dehydration stress. In addition, routine application is shown of cryopreservation for long-term conservation of in vitro propagated germplasm of the Gentianaceae.
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Cryopreservation of Gentianaceae: Trends and Applications
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10.1007/978-3-642-54102-5_11
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2015-01-01
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An aluminum alloy (Al-Zn-Mg-Cu) subjected to deep cryogenic treatment (DCT) was systematically investigated. The results show that a DCT-induced phase transformation varies the microstructures and affects the mechanical properties of the Al alloy. Both Guinier-Preston (GP) zones and a metastable η′ phase were observed by high-resolution transmission electron microscopy. The phenomenon of the second precipitation of the GP zones in samples subjected to DCT after being aged was observed. The viability of this phase transformation was also demonstrated by first-principles calculations.
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Deep-cryogenic-treatment-induced phase transformation in the Al-Zn-Mg-Cu alloy
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10.1007/s12613-015-1045-7
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2014-12-01
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This paper describes design and fabrication of a hybrid high temperature superconducting (HTS) magnet for a 150 kJ superconducting magnetic energy system. The hybrid HTS magnet, which employs both BSCCO taps and YBCO taps, is composed of 18 double pancake coils (DPC). Six DPC made of BSCCO are respectively installed on the top and bottom with an inner diameter of 240 mm, an outer diameter of 396 mm, and height of 11.5 mm. Six YBCO coils are mounted in the middle of the magnet with the inner and outer diameters of 264, 396 mm and height of 12.1 mm. Copper plates with thickness of 1 mm are arranged between DPC for the cooling of the heat, and epoxy resin plates with thickness of 0.2 mm are arranged between coil and copper plate for the insulation. The inductance of the magnet is about 11.06 H and the resistance is 169.5 Ω at the room temperature. In order to evaluation the performance of the hybrid magnet, each solidified DPC and the assembled magnet were tested in a bath of liquid nitrogen at 77 K. The resistances of 17 joints were also measured and evaluated by the standard four-probe method.
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Design and Fabrication of a Hybrid HTS Magnet for 150 kJ SMES
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10.1007/s10894-014-9744-z
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2014-12-01
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This work is dedicated to gas-bearing empty ice crystallites 100–500 μm in size, which were found for the first time in Paleogene diatomic clay in the upper part of the frozen sequence of Western Siberia. The spherical, caselike, and splintered crystallites with hexagonal and curved faces are not related to relict gas hydrates and are the results of shift deformations of plastic frozen clayey deposits under degassing of the above Cenomannian rocks. These data should be taken into account in modeling the fluid dynamics and geodynamics of the frozen sequences, including the shallow shelf of the Arctic seas.
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Gas-bearing ice crystallites in clayey deposits
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10.1134/S1028334X14120277
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2014-12-01
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Cryogenic propulsion systems using liquid hydrogen and liquid oxygen propellant combination are used in satellite launch vehicles in view of the higher specific impulse (I_SP). Due to extreme low temperature of cryogenic propellant and low density and explosive nature of LH_2, the development of cryogenic propulsion system is very complex and time consuming. In ISRO an indigenous cryogenic upper stage powered by an engine developing a nominal thrust of 73.5 kN in vacuum with a propellant loading of 12.8 tonnes is developed and successfully flight tested for the first time in GSLV D5 flight on 5th January 2014. A mathematical model is developed for finalizing the engine start and shut off sequence, ensuring smooth and safe ignition, predicting performance of subsystems under transient phase, nominal and off nominal conditions, control systems parameter settings and for the performance estimation of engine in sea level and flight. This paper highlights the configuration and working of a cryogenic engine, mathematical modelling of the engine, applications of the model in the cryogenic engine development and comparison of predicted values with the test results.
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Mathematical modelling of a cryogenic engine
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10.1007/s12572-015-0117-2
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2014-12-01
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A thermomechanical coupling numerical model is built to reproduce the deep cryogenic treatment (DCT) of a cold work die steel Cr8Mo2SiV (SDC99) Navy C-ring specimen and explore the transient temperature distribution and microstructure evolution in specimen. Furthermore, the predicted results are validated by x-ray diffraction analysis and hardness measurement. The results indicate that for both the quenching treatment (QT) and DCT, the differences in cooling rate and temperature distribution between the gap and core regions of specimen are significant. The gap region of specimen shows a more rapid cooling rate, while the core region of specimen presents a slower cooling rate. There is an underlying risk of hardening crack at the gap region of specimen during the cooling process. Both the cooling rate and the temperature difference that occurred in the DCT process are markedly smaller than that in the QT process. After QT, about 15.5% of austenite will still remain, especially in the edge and corner of specimen, which is a potential factor for component failure. Subjected to DCT, the microstructure distribution of specimen demonstrates a distinct change and finally the volume fraction of retained austenite decreases to about 2.3%, which principally localizes at the gap region of specimen. The hardness of specimen after DCT has been a dramatic increase and shows a uniform distribution. In comparison with the experimental data, the predicted results show a quite good accuracy. It indicates that the thermomechanical couple model employed in this study can be used to optimal control of the DCT process.
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Thermomechanical Analysis of Deep Cryogenic Treatment of Navy C-Ring Specimen
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10.1007/s11665-014-1239-6
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2014-12-01
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In this study, the effects of deep cryogenic treatment (DCT) on the wear resistance of AISI 52100 bearing steel were investigated. For this purpose, a number of bearing steel samples were held for different times (12, 24, 36, 48, 60 h) at deep cryogenic temperatures (−145 °C). The wear experiments were carried out in a ball–disk arrangement, by applying loads of 10 and 20 N and a sliding velocity of 0.15 m/s. After conducting the experimental studies, 36 h was found to be the optimal holding time. At this holding time, the wear rate and friction coefficient were decreased, while the hardness reached to maximum values. It was observed that DCT led to significant microstructural changes, which resulted in improved tribological properties.
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Effect of Deep Cryogenic Treatment on Wear Resistance of AISI 52100 Bearing Steel
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10.1007/s12666-014-0417-4
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2014-12-01
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The anthropogenic changes of permafrost are studied at the key sites in the European North, i.e., Koida Village (Mezen’ tundra), Nes’ Village (Kanin Peninsula), Shoina Village (Kanin Peninsula), Mezen’ Town, Vashutkiny Lakes (Bol’shezemel’skaya tundra), Amderma (Yugorskii Peninsula), and the northern part of Vaigach island. Geocryological characteristics of the sites are provided, and the main types of anthropogenic changes in permafrost conditions are described.
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Anthropogenic changes of permafrost in the European North and their consequences
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10.1134/S0097807814070069
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2014-12-01
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Cryopreservation, the storage of germplasm at ultra-low temperature is the most reliable tool for long-term preservation of plant genetic resources. Cryopreservation techniques are widely applied but the effect of light spectra on plant recovery after cryopreservation is largely unknown. Therefore, we investigated the effect of different light spectral qualities on survival and regeneration of shoot tips of potato ( Solanum tuberosum L.) cultivars Agrie Dzeltenie, Maret, Bintje, Désirée and Anti cryopreserved by the DMSO-droplet method. Prior to cryopreservation, the plants were stored under cool white fluorescent light (CW). Post-cryopreservation, the plants were allowed to regenerate under six different light qualities: CW, warm white light (HQI), blue LEDs (B), red LEDs (R), red with 10 % of blue (RB) and RBF - red with 10 % of blue with addition of 20 % of far-red LEDs. The light spectral quality had a significant effect on the survival and regeneration of potato shoot tips after cryopreservation. The combination of red light with 10 % of blue (RB) doubled the regeneration percentage of all cultivars, whereas red light (R) was not suitable for regeneration after cryopreservation. Specifically, the regeneration percentages were increased in RB compared to CW from 25.5 to 52.6 % for ‘Agrie Dzeltenie’, 25.0–43.6 % for ‘Maret’, 8.1–26.1 % for ‘Bintje’, 0.0–17.1 % for ‘Anti’ and 18.2–36.6 % for ‘Désirée‘. Therefore, the modification of light spectra during the recovery phase is a promising tool for increasing the regeneration of potato shoot tips after cryopreservation.
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Does light spectral quality affect survival and regeneration of potato (Solanum tuberosum L.) shoot tips after cryopreservation?
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10.1007/s11240-014-0559-4
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2014-12-01
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The beneficial effects of deep cryogenic treatment (DCT) at temperatures close to −180 °C on certain mechanical properties of steels are well known, although the metallurgical base mechanism of DCT still needs further clarification. In this study, the thermal decomposition of steel martensite (100Cr6) subjected to low-temperature soaking over different periods (SDCT = 5 min at −180 °C, LDCT = 24 h at −180 °C) is investigated by means of differential scanning calorimetry and dilatometry. The results were compared with those for the same conventionally quenched and tempered steel. Isochronal annealing experiments at different heating rates were performed, in order to highlight the main tempering stages and to obtain their relevant activation energies. DCT was clearly shown to lower the Ea of the pre-precipitation process more intensely than in the quenched steel. This result may probably be ascribed to an increased dislocation density and to the activation of the carbon segregation process in larger amounts of martensite. The precipitation of transition carbides was also enhanced by the low-temperature conditioning of martensite. As expected, DCT transformed the retained austenite, so that the corresponding peaks almost disappeared from both the dilatometric and the DSC patterns.
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Influence of deep cryogenic treatment on the thermal decomposition of Fe–C martensite
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10.1007/s10853-014-8527-2
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2014-12-01
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The present paper deals with experimental investigation of processes that occur when injecting a cryogenic fluid into water. The optical recording of the process of injection of a jet of liquid nitrogen into water has revealed the structure and the stages of this process. The results obtained can be used when studying a new method for producing gas hydrates based on the shock-wave method.
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Explosive boiling of liquid nitrogen
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10.1134/S0040601514130060
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2014-11-01
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Effects of Mn addition (17, 19, and 22 wt pct) on tensile and Charpy impact properties in three austenitic Fe-Mn-C-Al-based steels were investigated at room and cryogenic temperatures in relation with deformation mechanisms. Tensile strength and elongation were not varied much with Mn content at room temperature, but abruptly decreased with decreasing Mn content at 77 K (−196 °C). Charpy impact energies at 273 K (0 °C) were higher than 200 J in the three steels, but rapidly dropped to 44 J at 77 K (−196 °C) in the 17Mn steel, while they were higher than 120 J in the 19Mn and 22Mn steels. Although the cryogenic-temperature stacking fault energies (SFEs) were lower by 30 to 50 pct than the room-temperature SFEs, the SFE of the 22Mn steel was situated in the TWinning-induced plasticity regime. In the 17Mn and 19Mn steels, however, α ′-martensites were formed by the TRansformation-induced plasticity mechanism because of the low SFEs. EBSD analyses along with interrupted tensile tests at cryogenic temperature showed that the austenite was sufficiently deformed in the 19Mn steel even after the formation of α ′-martensite, thereby leading to the high impact energy over 120 J.
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Effects of Mn Addition on Tensile and Charpy Impact Properties in Austenitic Fe-Mn-C-Al-Based Steels for Cryogenic Applications
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10.1007/s11661-014-2513-9
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2014-11-01
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Tensile tests of titanium alloy and austenitic steel specimens have been conducted in the range of temperatures 300–4 K. Under deep-freezing conditions, there occurs a new type of scale effect – variation of low-temperature jumplike deformation, which causes a sharp variation of the plasticity characteristic (the relative elongation). The difference between jumplike deformation values in the maximum and minimum cross-sectional areas of standard cylindrical specimens is introduced as the scale effect measure. Via mathematical modeling performed for 03Kh20N16AG6 steel, we have obtained dependencies of the scale effect on the most critical factors – the trigger stress of deformation jump and specimen–test machine system stiffness. The scale effect nature is studied, and options of its minimization, in reference to the standardization of mechanical tests, are discussed.
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Jumplike Deformation as the Scale Effect Measure for the Metal Deformed Volume Under Deep-Freezing Conditions: Experiment and Modeling
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10.1007/s11223-014-9609-8
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2014-10-01
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Nonequilibrium nanocrystalline FCC solid solutions are obtained via the mechanical alloying of Cu_1.0 − x -Ag_ x powders ( x = 0.1, 0.2, …, 0.9, 1.0) with deformation under pressure and their properties are investigated. The chemical homogeneity, microstructure, mechanical properties, and thermal stability of the alloys are investigated. The alloys have the positive deviation of lattice parameters from the Vegard law with crystallite sizes of 20 nm, hardness exceeding the initial values of the components by 4.5–6 times, and a brittle character of fracture. The thermally induced decomposition of nonequilibrium solutions starts at temperatures close to room and is complete after heating to 500°C with the development of collective recrystallization.
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Formation and properties of copper-silver solid solutions upon severe deformation under pressure
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10.3103/S1062873814100189
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2014-10-01
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Effect of deep cryogenic treatment (DCT) on the microstructures and mechanical behavior of ultrafine-grained WC-12Co cemented carbide was investigated by using XRD, SEM, and DSC. The phase transformations of pure Co and binder phase Co in cemented carbide were analyzed in detail to correlate the strengthening mechanism with its α → ε phase transition. The results show that DCT resulted in a slight increase in hardness and bending strength of ultrafine-grained WC-12Co cemented carbide. For the ultrafine-grained cemented carbide after DCT, there is no significant change in the microstructure and the elemental distribution of the cemented carbides, but the fractured morphology shows a feature of plastic deformation. In the cases of pure Co and the binder phase Co in WC-12Co cemented carbide, they exhibit different features of phase transformation. The improvement of mechanical property of cemented carbide can be attributed to the increased amount of ε -Co in WC-12Co composites after DCT.
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Influence of Deep Cryogenic Treatment on Microstructures and Mechanical Properties of an Ultrafine-Grained WC-12Co Cemented Carbide
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10.1007/s40195-014-0134-3
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2014-10-01
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Epoxies have a wide range of applications in fuel tank fabrication, aerospace, electrical, electronic, and automobile industries. However, these resins are quite brittle, showing poor mechanical performance, especially at cryogenic temperature. The properties of functionalized multi-walled carbon nanotube (MWCNTs)-reinforced epoxy composites were investigated to develop advanced composites for cryogenic use. Two methods were adopted to modify MWCNTs. MWCNTs were first treated by acid mixture, and then maleic anhydride (MA) and isophorone diisocyanate (IPDI) grafting was carried out. At last, the functionalized MWCNTs were integrated into epoxy to prepare MWCNT-reinforced epoxy composites. Raman and XPS analysis proved the effectiveness of acid mixture treatment and confirmed the grafting reaction of MA and IPDI with MWCNTs. TEM analysis indicated that MA and IPDI had been grafted onto the surface of MWCNTs and formed a thin layer. The tensile strength, Young’s modulus, and impact strength of composites at liquid nitrogen temperature (77 K) are all enhanced by the addition of MWCNTs. Results of dynamic mechanical analysis indicated that introducing a small amount of functionalized MWCNTs to epoxy can enhance their storage modulus at 77 K and glass-transition temperature of composites. The results indicated that surface modified MWCNTs can be effectively utilized to enhance the properties of epoxy-based composites at cryogenic temperature.
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Surface functionalized carbon nanotubes and its effects on the mechanical properties of epoxy based composites at cryogenic temperature
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10.1007/s00289-014-1202-6
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2014-10-01
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In this study, liquid nitrogen was applied to grind SiCp/Al composites with high volume fraction and large SiC particle at different levels of cutting conditions, and the effects of grinding depth and speed on grinding force, surface morphology, and surface roughness were investigated. At the same time, the effect of cryogenic cooling was also compared with that of conventional wet grinding. The experimental results indicated that cryogenic cooling is effective in enhancing supporting function of Al matrix to the SiC particles and improving surface quality. Additionally, the brittle fracture of SiC particles was suppressed and some ductile streaks on SiC particle could be observed.
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Machining Characteristics in Cryogenic Grinding of SiCp/Al Composites
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10.1007/s40195-014-0126-3
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2014-10-01
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In this study, the spread of cryogenic liquid due to a limited period of release is investigated for the first time to clarify the unclear conventional concept regarding two release types, continuous and instantaneous release. In describing instantaneous release, a discharge time has been assumed to be infinitesimally small; however, such an assumption is unreal because there exists a finite period of release no matter how rapid it is. If the discharge time is less than the entire time domain, the instantaneous release model should be added to the continuous model from the end of the time. This combined release that consists of the initial continuous model and subsequent instantaneous model is more realistic than the instantaneous release. The physical phenomenon is governed by three parameters: the evaporation rate per unit area, release time, and spill quantity. Third-order perturbation solutions are obtained and compared with a numerical solution to verify the perturbation solution. For the same spill quantity, the combined model that consists of continuous and subsequent instantaneous model is necessary for small release times, whereas the continuous model is only required for large release times. Additionally, the combined release model is necessary for a small spill quantity at a fixed release time. These two release models are clearly distinguished using the perturbation solution.
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Study of continuous spill with a limited period of release
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10.1007/s12206-014-0947-z
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2014-09-01
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Design specifications for the support structures of low temperature instrumentation often call for low thermal conductivity between temperature stages, high stiffness, and specific load bearing capabilities. While overall geometric design plays an important role in both overall stiffness and heat conduction between stages, material selection can affect a structure’s properties significantly. In this contribution, we suggest and compare several alternative materials to the current standard materials for building cryogenic support structures.
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Material Selection for Cryogenic Support Structures
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10.1007/s10909-013-1052-x
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2014-09-01
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Cryogenic test setups with controlled stray light environments capable of reaching ultra-low radiative background levels are required to test far infrared (FIR) and submillimeter (sub-mm) wave radiation detectors for future space based observatories. In recent experiments (Nature Commun 5:3130, 2014 ), in which 1.54 THz radiation was coupled onto an antenna-coupled kinetic inductance detector (KID), we found a higher than expected optical loading. We show that this can be explained by assuming heating of the metal mesh IR filters and re-radiation onto the KID. Note that the total power from the cryogenic black body source used in the experiments (at T = $$3$$ 3 – $$25$$ 25 K) is much larger than the power inside the $$1.5$$ 1.5 – $$1.6$$ 1.6 THz band we use to calibrate our detector. The out-of-band radiation can have up to 5 orders of magnitude more power than inside the $$1.5$$ 1.5 – $$1.6$$ 1.6 THz band of interest. A strategy to mitigate the filter heating problem is presented, and when it is implemented, the validated upper limit for stray light at the detector level is down to few aW.
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Study on Optical Filter Heating in Background Limited Detector Experiments
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10.1007/s10909-014-1184-7
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2014-09-01
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The next generations of cosmic microwave background (CMB) instruments will be dedicated to the detection and characterisation of CMB B-modes. To measure this tiny signal, instruments need to control and minimise systematics. Signal modulation is one way to achieve such a control. New generation of focal planes will include the entire detection chain on chip. In this context, we present a superconducting coplanar switch driven by DC current. It consists of a superconducting micro-bridge which commutes between its on (superconducting) and off (normal metal) states, depending on the amplitude of the current injection. To be effective, we have to use a high normal state resistivity superconducting material with a gap frequency higher than the frequencies of operation (millimeter waves). Several measurements were made at low temperature on NbN and yielded very high resistivities. Preliminary results of components dc behavior is shown. Thanks to its low power consumption, fast modulation and low weight, this component is a perfect candidate for future CMB space missions.
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Superconducting NbN Coplanar Switch Driven by DC Current for CMB Instruments
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10.1007/s10909-014-1103-y
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2014-09-01
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Space-charge build-up phenomena are investigated in germanium detectors for dark matter search, associated with the thermal emission of carriers by the H $$^{-}$$ - -like, dopant-related A $$^{+ }$$ + and D $$^{-}$$ - shallow trap centers. Evidence for such processes follows from a combined study of the time evolution of the pattern of charge sharing between the different collection electrodes of the device, and of the kinetics of carrier emission by the A $$^{+ }$$ + and D $$^{- }$$ - centers. Implications for detector physics are discussed.
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$$\hbox {H}^{-}$$
H
-
-Like Centers and Space-Charge Effects in Cryogenic Germanium Detectors for Dark Matter Search
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10.1007/s10909-013-1060-x
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2014-09-01
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A new set of experimental data is presented for the mean drift lengths and the drift velocities of hot electrons and holes as a function of the electric field in ultra-pure and in lightly doped (n- and p-type) germanium single crystals at mK temperatures. Measurements are made in the field range between $$\sim $$ ∼ 0.1 and 15 V/cm, typical for the operation of cryogenic germanium detectors for dark matter search. The analysis of the experimental data strongly suggests that the dominant trapping centers are the dopant species in the neutral state.
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Hot Carrier Trapping in High-Purity and Doped Germanium Crystals at Millikelvin Temperatures
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10.1007/s10909-014-1088-6
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2014-09-01
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A method is presented to determine the field dependence of the intervalley scattering rate for hot electrons in germanium, based on an analysis of electron straggle in a detector crystal fitted with segmented electrodes. Measurements in high-purity and in lightly doped n- and p-type crystals at millikelvin temperatures demonstrate the dominant role of impurity scattering at low field ( $$<\sim $$ < ∼ a few V/cm), whereas phonon scattering takes precedence at higher field intensities. An analysis of the experimental data by reference to past investigations of the acoustoelectric effect in germanium strongly suggests that the impurities involved are the dopant species in the neutral state.
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Intervalley Scattering of Hot Electrons in Germanium at Millikelvin Temperatures
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10.1007/s10909-014-1091-y
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2014-09-01
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This experimental work reports the results of a study addressing tool wear, surface topography, and x-ray diffraction analysis for the finish cutting process of room-temperature austenitic NiTi alloy. Turning operation of NiTi alloy was conducted under dry, minimum quantity lubrication (MQL) and cryogenic cooling conditions at various cutting speeds. Findings revealed that cryogenic machining substantially reduced tool wear and improved surface topography and quality of the finished parts in comparison with the other two approaches. Phase transformation on the surface of work material was not observed after dry and MQL machining, but B19′ martensite phase was found on the surface of cryogenically machined samples.
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Machining and Phase Transformation Response of Room-Temperature Austenitic NiTi Shape Memory Alloy
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10.1007/s11665-014-1058-9
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2014-09-01
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The effective mass of the electron neutrino can be probed by studying the $$^{163}$$ 163 Ho electron capture decay with cryogenic microcalorimeters. The goal is to perform a calorimetric experiment, where all the energy released in the decay is measured except for the kinetic energy of the neutrino. To achieve such a goal, multiple approaches are being investigated to enclose the radioactive source in a microcalorimeter absorber without affecting the thermal properties of the absorber material. One such approach is to implant the radioactive isotope into a gold absorber, as gold is successfully used in similar applications. We measured the heat capacity of gold films, implanted with various concentrations of holmium and erbium (a byproduct of the $$^{163}$$ 163 Ho fabrication), in the temperature range 70–300 mK. Our results show that the specific heat capacity of the films is not affected by the implant, making this a viable option for a future experiment. We also verified that the implant does not affect the crystal structure of the gold film.
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Thermal Properties of Holmium-Implanted Gold Films
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10.1007/s10909-014-1156-y
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2014-09-01
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Formation of ordered structures from a large number (∼10^4) of charged diamagnetic macroparticles in a cusp magnetic trap under microgravity conditions is experimentally studied. The experiments are performed onboard the International Space Station. Dusty plasma structures in a cryogenic d.c. glow discharge (cryogenic dusty plasma) are examined. Ultrahigh charging of dust macroparticles under the action of an electron beam is experimentally obtained and studied. Results of an experimental investigation of various regimes of the Brownian motion of interacting dust particles in the plasma are presented. A method of determining particle interaction forces in nonideal systems with isotropic pair potentials is proposed. The method is based on solving an inverse problem that describes the motion of interacting particles by a system of the Langevin equations and allows reconstruction of parameters of the external confining potential without using a priori information about the friction coefficients of particles.
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Coulomb systems of strongly interacting dust particles: Laboratory and microgravity conditions
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10.3103/S8756699014050021
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2014-09-01
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We established a simple thermal model of the heat flow in a large crystal detector designed for a neutrinoless double beta decay experiment. The detector is composed of a CaMoO $$_{4}$$ 4 crystal and a metallic magnetic calorimeter (MMC). The thermal connection between the absorber and the sensor consists of a gold film evaporated on the crystal surface and gold bonding wires attached to this film and the MMC sensor. The model describes athermal and thermal processes of heat flow to the gold film. A successive experiment based on optimization calculations of the area and thickness of the gold film showed a significant improvement in the size and rise-time of the measured signals.
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Thermal Model and Optimization of a Large Crystal Detector Using a Metallic Magnetic Calorimeter
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10.1007/s10909-014-1139-z
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2014-09-01
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We report the realization of a robust magnetic transport scheme to bring >3 × 10^8 ultracold ^87Rb atoms into a cryostat. The sequence starts with standard laser cooling and trapping of ^87Rb atoms, transporting first horizontally and then vertically through the radiation shields into a cryostat by a series of normal- and superconducting magnetic coils. Loading the atoms in a superconducting microtrap paves the way for studying the interaction of ultracold atoms with superconducting surfaces and quantum devices requiring cryogenic temperatures.
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Magnetic conveyor belt transport of ultracold atoms to a superconducting atomchip
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10.1007/s00340-014-5790-5
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2014-08-01
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We have demonstrated a combined test of the submillimeter-wave SIS photon detectors and GaAs-JFET cryogenic integrated circuits. A relatively large background photo-current can be read out by fast-reset integrating amplifiers. An integration time of 1 ms enables fast frame rate readout and large dynamic range imaging, with an expected dynamic range of 8,000 in 1 ms. Ultimate fast and high dynamic range performance of superconducting tunnel junction detectors (STJ) will be obtained when photon counting capabilities are employed. In the terahertz frequencies, when input photon rate of 100 MHz is measured, the photon bunching gives us enough timing resolution to be used as phase information of intensity fluctuation. Application of photon statistics will be a new tool in the terahertz frequency region. The design parameters of STJ terahertz photon counting detectors are discussed.
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Fast and High Dynamic Range Imaging with Superconducting Tunnel Junction Detectors
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10.1007/s10909-013-1022-3
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2014-08-01
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The SuperCDMS collaboration is presently operating a 9 kg Ge payload at the Soudan Underground Laboratory in their direct search for dark matter. The Ge detectors utilize double-sided athermal phonon sensors with an interdigitated electrode structure (iZIPs) to reject near-surface electron-recoil events. These detectors each have a mass of 0.6 kg and were fabricated with photolithographic techniques. The detector fabrication advances required and the production yield encountered are described.
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Detector Fabrication Yield for SuperCDMS Soudan
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10.1007/s10909-014-1100-1
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2014-08-01
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SRON is developing TES detectors based on a superconducting Ti/Au bilayer on a suspended SiN membrane for the short-wavelength band of the SAFARI instrument on SPICA mission. We have recently replaced the wet KOH etching of the Si substrate by deep reactive ion etching. The new process enables us to fabricate the detectors on the substrate and release the membrane at the very last step. Therefore the production of SAFARI large arrays (43 $$\,{\times }\,$$ × 43) on thin SiN membrane (250 nm) is feasible. It also makes it possible to realize narrow supporting SiN legs of $$\le $$ ≤ 1 $$\upmu $$ μ m, which are needed to meet SAFARI NEP requirements. Here we report the current–voltage characteristics, noise performance and impedance measurement of these devices. The measured results are then compared with the distributed leg model that takes into account the thermal fluctuation noise due to the SiN legs. We measured a dark NEP of $$\sim $$ ∼ 0.7 aW/ $$\sqrt{\hbox {Hz}}$$ Hz , which is 1.6 times higher than the theoretically expected phonon noise.
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Characterization of Low Noise TES Detectors Fabricated by D-RIE Process for SAFARI Short-Wavelength Band
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10.1007/s10909-014-1131-7
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2014-08-01
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For compounds dissolved in non-polar solvents, nuclear magnetic resonance spectroscopic investigations have benefited greatly from the advent of cryogenically cooled probes. Unfortunately the allure of significant increases in sensitivity may not be realized for compounds such as metabolites that are dissolved in solvents with high ionic-strengths such as solutions typically utilized for metabolomic or biomolecular investigations. In some cases there is little benefit from a cryogenically cooled probe over a conventional room temperature probe. Various sample preparation methods have been developed to minimize the detrimental effects of salt; for large numbers of metabolomic samples these preparation methods tend to be onerous and impractical. An alternative to manipulating the sample, is to utilize a probe that is designed to have a higher tolerance for solutions with high ionic-strengths. In order to acquire high-quality optimal data and choose the appropriate probe configuration (especially important for comparative quantitative investigations) the effects of salts and buffers on cryogenic probe performance must be understood. Herein we detail sample considerations for two cryogenic probes, a standard 5 mm and a narrow diameter 1.7 mm, in an effort to identify via integrals, intensities and noise levels the optimal choice for biomolecular investigations.
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Biomolecular sample considerations essential for optimal performance from cryogenic probes
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10.1007/s11306-013-0620-z
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2014-08-01
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The SuperCDMS experiment relies on detection of free charges generated in high purity germanium (HPGe) crystals by particle interactions. To better understand long-term trapping effects which make carriers unavailable for such rapid ionization measurements, we used infrared LEDs ( $$\lambda $$ λ = 940 nm) to create electron-hole pairs near each face of a HPGe SuperCDMS detector operated under applied electric field at 400 mK. By alternating the polarity of an applied electric field, we were able to study propagation of each carrier through the crystal separately. Asymmetry in the resulting current transients revealed differences in trapping characteristics between electrons and holes at these low temperatures.
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Charge Transport Asymmetry in Cryogenic High Purity Germanium
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10.1007/s10909-014-1111-y
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2014-08-01
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Ultra-low temperature sensors provide unprecedented performances in X-ray and far infrared astronomy by taking advantage of physical properties of matter close to absolute zero. CESAR is an FP7 funded project started in December 2010, that gathers six European laboratories around the development of high performances cryogenic electronics. The goal of the project is to provide far-IR, X-ray and magnetic sensors with signal-processing capabilities at the heart of the detectors. We present the major steps that constitute the CESAR work, and the main results achieved so far.
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CESAR: Cryogenic Electronics for Space Applications
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10.1007/s10909-013-1021-4
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2014-07-01
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In this paper, we study some components of a terawatt femtosecond laser system operating with a pulse repetition rate of 1 kHz under development. The system consists of optically synchronized pump and amplification channels; the amplification channel is based on parametric amplification in an LBO crystal, and the pump channel is based on diode-pumped Yb^3+-doped laser media at 80 K. In the pump channel, picosecond pulses are generated. The system is based on the chirped-pulse amplification technique. For the pump channel, parameters and alignments of the holographic grating-based stretcher-compressor system are determined. A diode-pumped (up to 1 kW) Yb:Y_2O_3 ceramic multipass amplifier operating at 77 K was designed. The data can be used in the development of cryogenic multistage femtosecond laser systems operating in a kilohertz pulse-repetition-rate mode.
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Pump channel of parametric amplifier of terawatt femtosecond Yb laser system
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10.1134/S1024856014040137
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2014-07-01
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The strengthening and change in austenite stability when steel of X18H10 type alloyed by nitrogen are investigated, for applications where corrosion-resistant structural steel must operate satisfactorily at both high and cryogenic temperatures. Alloying by nitrogen may be regarded as a promising means of increasing the strength and stability of austenitic stainless steel. Preliminary cold or hot working increases the likelihood of martensite formation under load and consequently limits the working temperature range of the steel. High-strength nonmagnetic nitrogen steel based on X18AH10 steel with up to 0.22% N may be used for undeformable components at cryogenic temperatures. Without nitrogen, deformational martensite is always formed in such steel at temperatures below −70°C. High strength, plasticity, and ductility may only be ensured in such steel by means of the TRIP effect or reduction in the grain size. Nitrogen effectively strengthens the solid solution in the high-temperature state. The use of combined high-temperature deformation and moderate-temperature deformation permits additional strengthening of the steel during thermomechanical treatment, including strain aging, which is effective where thermostable steel is required.
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Influence of alloying by nitrogen on the strength and austenite stability of X18H10 steel
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10.3103/S0967091214070110
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2014-07-01
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High-strength corrosion-resistant steels with controlled martensitic transformation developed at the V. P. Glushko Energomash Research and Production Association, are studied. The main principles of their alloying and heat treatment are described. The advantages and prospects of the use of the new steels for making elastic metallic seals and soldered and welded units of liquid-propellant engines with cryogenic fuel components are presented.
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A Study and Development of High-Strength Corrosion-Resistant Steels with Controlled Martensitic Transformation for Cryogenic Engineering
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10.1007/s11041-014-9723-z
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2014-07-01
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The mechanism of structure formation is proposed in heterogeneous crystallization of droplets of binary eutectic solutions containing carbon nanotube particles in cryogenic liquids. Theoretical relationships are derived for calculating the rate of crystallite growth and the size of salt nanocrystals that form. Calculated values of the size of produced nanocrystals are compared with experimental data.
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Heterogeneous cryogenic crystallization of suspensions containing carbon nanotubes
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10.1134/S0040579514030051
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2014-07-01
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This paper presents the performance of production Band 3 receivers (84-116 GHz) for the Atacama Large Millimeter Array (ALMA) that operate in Chile at 5000 m altitude. The fabrication, and testing of a total of 73 receivers necessitated stringent quality control during assembly and custom designed automated test set for accurate and reproducible measurement results. Interfaces to the ALMA receiver system are described in details. The average single side band noise temperature of band 3 production receivers is 33.2 K, with a minimum of 24.4 K and a maximum of 45.5 K. As for image rejection, the average is 18 dB, with a minimum at 12 dB and a maximum of 21 dB. Other performances with test methodology are described such as gain variation within the IF band, the gain and phase stability, gain compression, and beam patterns. This paper also describes the interfaces to the ALMA front end system, the testing methodology used, and the test results.
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Performance of the Production Band 3 receivers (84-116 GHz) for the Atacama Large Millimeter Array (ALMA)
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10.1007/s10762-014-0071-2
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2014-07-01
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Photographic properties of one of atomic photodetectors are studied at the temperature of liquid nitrogen. The characteristic curves obtained at room and cryogenic temperatures indicate that the detector retains its physical and photographic properties, and its possibilities can be expanded to studies of deeply frozen samples. The data obtained point to an increase in the sensitivity of the photographic material frozen to cryogenic temperatures at short exposures.
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Possibilities of cryogenic autoradiography
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10.1134/S1061934814070107
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2014-07-01
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We present measurements of the absorption and emission cross-sections for Yb:YAG , Yb:LuAG and Yb:CaF _2 as a function of temperature between 80 and 340 K. The cross-sections are determined by the combination of the McCumber relation and the Fuchtbauer–Ladenburg (FL) equation to achieve reliable results in spectral regions of high and low absorption. The experimental setup used for the fluorescence measurements minimizes re-absorption effects due to the measurement from small sample volume, providing nearly undisturbed raw data for the FL approach. The retrieved cross-sections together with the spectral characteristics of the tested materials provide important information for the design of energy efficient, high-power laser amplifiers.
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Spectroscopic characterization of Yb^3+-doped laser materials at cryogenic temperatures
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10.1007/s00340-013-5650-8
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2014-07-01
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The NICA cryogenics will be based on the modernized liquid helium plant that was b uilt in the early 90’s for the superconducting synchrotron known as the Nuclotron. The main goals of the modernization are: increasing of the total refrigerator capacity from 4000 W to 8000 W at 4.5 K, making a new distribution system of liquid helium, and ensuring the shortest possible cool down time. These goals will be achieved by means of an additional 1000 l/hour helium liquefier and “satellite” refrigerators located near the accelerator rings. This report describes the design choices of the NICA, demonstrates helium flow diagrams with major new components and briefly informs of the liquid nitrogen system that will be used for shield cooling at 77 K and at the first stage of cooling down of three accelerator rings with the total length of about 1 km and “cold” mass of 290 tons.
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Cryogenics for the future accelerator complex NICA at JINR
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10.1134/S1547477114040037
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2014-07-01
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A novel concept of hybrid cryogenic distillation network has been explored which maximizes the benefits of both desublimation or solid-vapor based separation as well as distillation or vapor-liquid equilibrium based separation during the separation of carbon dioxide from methane or natural gas. Process network synthesis has been performed for four case studies with high carbon dioxide (72 mole%) and medium carbon dioxide (50 mole%) natural gas feed streams. The benefits of optimal locations for cryogenic packed beds were investigated. A conventional cryogenic network consisting of multiple distillation columns with butane as additive for extractive distillation was also studied and presented in this paper. Process modeling of cryogenic distillation network with MESH equations was attempted using an integrated dual loop (C+3) convergence and the results were compared with Aspen Plus simulator for benchmarking. The prediction of solidification region was employed using experimental data from literature to avoid solidification regions in the column. The proposed hybrid cryogenic distillation network showed promising potential for energy and size reduction.
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Performance enhancement and energy reduction using hybrid cryogenic distillation networks for purification of natural gas with high CO_2 content
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10.1007/s11814-014-0038-y
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2014-06-25
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We report on experimental results of the thermal conductivity k of highly porous Si in the temperature range 4.2 to 20 K, obtained using the direct current (dc) method combined with thermal finite element simulations. The reported results are the first in the literature for this temperature range. It was found that porous Si thermal conductivity at these temperatures shows a plateau-like temperature dependence similar to that obtained in glasses, with a constant k value as low as 0.04 W/m.K. This behavior is attributed to the presence of a majority of non-propagating vibrational modes, resulting from the nanoscale fractal structure of the material. By examining the fractal geometry of porous Si and its fractal dimensionality, which was smaller than two for the specific porous Si material used, we propose that a band of fractons (the localized vibrational excitations of a fractal lattice) is responsible for the observed plateau. The above results complement previous results by the authors in the temperature range 20 to 350 K. In this temperature range, a monotonic increase of k with temperature is observed, fitted with simplified classical models. The extremely low thermal conductivity of porous Si, especially at cryogenic temperatures, makes this material an excellent substrate for Si-integrated microcooling devices (micro-coldplate). PACS 61.43.-j; 63.22.-m; 65.8.-g
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Thermal conductivity of highly porous Si in the temperature range 4.2 to 20 K
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10.1186/1556-276X-9-318
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2014-06-01
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Recently, a use of difficult to cut materials including titanium alloy has been substantially increasing in aerospace and automotive industries. Eco-friendly machining technology, which eliminates or minimizes cutting fluids in machining fields, has been emerged in compliance with green manufacturing trend. In this regard, machining technologies, such as hard milling, laser assisted machining (LAM), and enhanced lubrication/cooling method, have been adapted by the industries. Among the technologies, cryogenic machining has been considered for a viable solution for the materials without any environmental problems. LAM and minimum quantity lubrication (MQL) can be useful method to cut these materials with an appropriate use. In this study, machining performance of ecofriendly machining techniques was compared experimentally for the titanium alloy (Ti-6Al-4V). The machining performance was evaluated in terms of tool wear and cutting force. From experimental results, coated cutting tool with flood cooling condition was not recommended in titanium machining. The cryogenic, MQL, LAM showed outstanding machining performance than dry and flood cooling. Especially MQL machining was superior with relatively simple system setup. In addition, lubrication and cooling mechanism by combination of MQL and cryogenic reduced cutting force and tool wear. For energy consumption, MQL and cryogenic methods can be a sustainable solution.
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Eco-friendly face milling of titanium alloy
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10.1007/s12541-014-0451-5
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2014-06-01
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The hydrodynamic processes occurring at injection of cryogenic liquid into water pool were studied experimentally. Processes accompanying the phase transitions were registered. Data testify the developing pressure burst with an amplitude sufficient for possible formation of gas hydrates when methane is injected as a cryogenic fluid.
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Boiling-up of liquid nitrogen jet in water
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10.1134/S0869864314030020
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2014-06-01
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In this study, the effects of deep cryogenic treatment (93 K) on the surface and sub-surface wear development of H13A cobalt-bonded tungsten carbide cutting inserts during the wet machining of AISI 1045 steel were investigated. Cutting inserts were subjected to short periods (171–553 s) of turning at cutting speeds of 50–140 m/min, during which time mass measurements were taken and the worn edges were imaged and scanned, by optical microscopy and light interferometry, at regular intervals. Sections were taken following machining so that sub-surface features could be observed by scanning electron microscopy. It was determined that cryogenic treatment resulted in a 9.2 % increase in hardness and an increase in abrasive wear resistance, although microstructural changes and sub-surface behaviours suggested a corresponding decrease in toughness may have occurred.
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Effects of deep cryogenic treatment on the wear development of H13A tungsten carbide inserts when machining AISI 1045 steel
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10.1007/s11740-013-0518-7
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2014-05-01
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The behavior of soil solutions in seasonally freezing solonchaks of Mongolia is discussed on the basis of the results of simulation experiments with the use of the FREEZBRINE model of physicochemical equilibria. Data on the chemical composition of soil solutions in solonchaks of the Ekhiin-Gol oasis have been used for modeling. The freezing temperatures; the character of the changes in the composition of the unfrozen brine; and the temperatures and intensities of the precipitation of hydrohalite, mirabilite, calcite, gypsum, and other salts have been calculated. The results obtained in this study allow us to estimate the contribution of the winter period of the soil functioning to the development of the salt profile in the solonchaks. One of the consequences of the cryogenic transformation of soil solutions in these solonchaks is a predominance of the sulfate type of salinization.
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Cryogenic transformation of soil solutions and the development of salt profiles in solonchaks of Mongolia according to the results of modeling
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10.1134/S1064229314050068
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2014-05-01
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There has been significant work on establishing relationships between machining performance and the cutting parameters for various work materials. Recent trends in machining research show that major efforts are being made to understand the impact of various cooling/lubrication methods on machining performance and surface integrity characteristics, all aimed at improving process and product performance. This study presents the experimental results of cryogenic machining of Inconel 718, a high-temperature aerospace alloy, and comparison of its performance in dry and minimum quantity lubrication machining. Experimental data on force components, progressive tool wear parameters such as flank wear, notch wear, crater wear, cutting temperature, chip morphology, and surface roughness/topography of machined samples are presented. New findings show that cryogenic machining is a promising research direction for machining of high-temperature aerospace alloy, Inconel 718, as it offers improved machining performance in terms of reduced tool wear, temperature, and improved surface quality. It was also found that the number of nozzles in cryogenic machining plays a vital role in controlling cutting forces and power consumption in cryogenic machining of Inconel 718.
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Evaluation of machining performance in cryogenic machining of Inconel 718 and comparison with dry and MQL machining
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10.1007/s00170-014-5683-0
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2014-05-01
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With the rapid growth in demand for industrial gas in steel and chemical industries, there has been significant emphasis placed on the development of China’s large-scale air separation technology. Currently, the maximum capacity of a single unit has been able to attain 120000 Nm^3/h (oxygen), and the specific power consumption of 0.38 kWh/m^3. This paper reviews the current state-of-the-art for large-scale cryogenic air separation systems being deployed in China. A brief introduction to the history and establishment of the large-scale cryogenic air separation industry is presented. Taking the present mainstream large-scale air separation unit operating at 60000 Nm^3/h (oxygen) as an example, the technological parameters and features of the involved key equipment, including a molecular sieve adsorber, air compressor unit, plate-fin heat exchanger, turbo-expander and distillation column are described in detail. The developing 80000–120000 Nm^3/h air separation processes and equipment are also introduced. A summary of the existing problems and future developments of these systems in China are discussed.
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Research and development of large-scale cryogenic air separation in China
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10.1631/jzus.A1400063
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2014-05-01
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Accurate thermal expansion data of material at low temperatures are important in material selection and structural design for a cryogenic system. In this study, an experimental setup with a proportional-integral-derivative (PID) temperature control system was developed to measure the thermal expansion of solid materials at low temperatures (77–293 K), using the strain gage method. To avoid the impact of the varied sensitivity coefficient of the strain gage with the temperature to ensure an accurate measurement, we corrected the sensitivity coefficient in the temperature range of 77–293 K, by comparing the measured thermal expansion data for 304 stainless steel with the source data from the National Institute of Standards and Technology, USA. With the corrected sensitivity coefficient of the strain gage, the measured linear contractions of oxygen-free copper become quite consistent with the NIST data (with a relative deviation of 2.37%) for the cooling-down process from 293 K to 80 K.
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Measurement of thermal expansion at low temperatures using the strain gage method
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10.1631/jzus.A1400051
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2014-04-01
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In the present study, numerical calculations of the flow-field around the airfoil model are performed by using the OpenFOAM in high subsonic flows. The airfoil model is NACA 64A010. The maximum thickness is 10 % of the chord length. The SonicFOAM and the RhoCentralFOAM are selected as the solver in high subsonic flows. The grid point is 158,000 and the Mach numbers are 0.277 and 0.569 respectively. The CFD data are compared with the experimental data performed by the cryogenic wind tunnel in the past. The results are as follows. The numerical results of the pressure coefficient distribution on the model surface calculated by the SonicFOAM solver showed good agreement with the experimental data measured by the cryogenic wind tunnel. And the data calculated by the SonicFOAM have the capability for the quantitative comparison of the experimental data at low angle of attack.
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A study on high subsonic airfoil flows in relatively high Reynolds number by using OpenFOAM
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10.1007/s11630-014-0687-5
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2014-04-01
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Morphology, composition, age and origin of carbonate spherulites from caves of Western Urals
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10.1134/S0016702914020049
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2014-04-01
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Thin films of nanoporous palladium (np-Pd) were produced from binary palladium-nickel (Pd-Ni) precursor alloys. A suitable precursor alloy and a method of dealloying to yield optimum nanoporosity (average pore/ligament size of 7 nm) were developed by studying the effects of various processing parameters on final microstructure. To obtain crack-free np-Pd, a 100 nm thin film of 20 at. pct Pd (80 at. pct Ni) can be dealloyed for ~5 hours in a 1 M solution of sulfuric acid, with oleic acid and oleylamine added as surfactants. Both shorter and longer dealloying times, as well as heating, inhibit the formation of crack-free np-Pd. Stress measurements at different stages of dealloying revealed that the necessary dealloying time is determined by the diffusion-controlled corrosion reaction occurring within the thin film during dealloying. Strong interaction between hydrogen and np-Pd was reflected in the stress evolution during dealloying. A mechanism is proposed for the formation of a Ni-rich dense top layer that results from H-induced swelling during initial dealloying and permits the development of defect-free np-Pd beneath, by limiting the speed of dealloying.
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Engineering Defect-Free Nanoporous Pd from Optimized Pd-Ni Precursor Alloy by Understanding Palladium-Hydrogen Interactions During Dealloying
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10.1007/s11661-013-2154-4
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2014-04-01
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We report the progress of developing a fiber-optic probe hydrophone (FOPH) system applicable to the measurement of local density/pressure fluctuations in a cryogenic liquid. The measurement principle is based on a law of classical optics known as “Fresnel’s reflection loss.” We use this principle at the end-face of a single-mode optical fiber that is immersed in liquid helium. Since the refraction index of liquid ^4He is a function of density, and the refraction index of the core of the optical fiber is constant, the pressure can be obtained by measuring the reflectivity. We have succeeded in measuring the temperature dependence of the static density, and we go on to discuss the possibility of application to acoustic pressure measurements.
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Development of a Fiber-Optic Probe Hydrophone for a Cryogenic Liquid
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10.1007/s10909-013-0962-y
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2014-04-01
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The present article focuses on modeling issues to simulate cryogenic fluid cavitating flows. A revised cavitation model, in which the thermal effect is considered, is derivated and established based on Kubota model. Cavitating flow computations are conducted around an axisymmetric ogive and a 2D quarter caliber hydrofoil in liquid nitrogen implementing the revised model and Kubota model coupled with energy equation and dynamically updating the fluid physical properties, respecitively. The results show that the revised cavitation model can better describe the mass transport process in the cavitation process in cryogenic fluids. Compared with Kubota model, the revised model can reflect the observed “frosty” appearance within the cavity. The cavity length becomes shorter and it can capture the temperature and pressure depressions more consistently in the cavitating region, particularly at the rear of the cavity. The evaporation rate decreases, and while the magnitude of the condensation rate becomes larger because of the thermal effect terms in the revised model compared with the results obtained by the Kubota model.
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A Rayleigh-Plesset based transport model for cryogenic fluid cavitating flow computations
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10.1007/s11433-013-5198-y
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2014-04-01
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Cryogenic treatment is a recent advancement in the field of machining to improve the properties of cutting tool materials. Tungsten carbide is the most commonly used cutting tool material in the industry and the technique can also be extended to it. Although the importance of tempering after cryogenic treatment has been discussed by many researchers, very little information is available in published literature about the effect of multi-tempering after cryogenic treatment. In this study, an attempt has been made to understand effect of the number of post-tempering cycles during cryogenic treatment on tungsten carbide–cobalt inserts. Metallurgical investigations have been performed to observe the effect of such post-tempering on the inserts by analysing microhardness and micro-structural changes. The crystal structure and morphology were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction analysis. Metallurgical investigations revealed a significant improvement in tungsten carbide inserts having three tempering cycles, after cryogenic treatment, with marginal differences for two cycles of tempered inserts, established by the study of wear behaviour in turning.
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Effect of tempering after cryogenic treatment of tungsten carbide–cobalt bounded inserts
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10.1007/s12034-014-0634-9
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2014-03-01
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This article tells the story of the Central Helium Liquefier (CHL) at the Thomas Jefferson National Accelerator Facility (JLab), one of the US National Laboratories. JLab’s successful superconducting radio frequency accelerator was only possible because a group of JLab engineers successfully tackled a complex of difficulties to build a cryogenic system that included the CHL, a task that required advancing the frontier of cryogenic technology. Ultimately, these cryogenic advances were applied far beyond JLab to the benefit of cutting-edge programs at other US national laboratories (Oak Ridge, Brookhaven, and the Facility for Rare Isotope Beams at MSU) as well as NASA. This innovation story dramatizes the sort of engineer-driven technological problem solving that allows the successful launch and operation of experimental projects. Along the way, the CHL story also provides an important addition to our understanding of the role played by engineers and industry in creating knowledge at physics laboratories.
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Engineering the Big Chill: The Story of JLab’s Central Helium Liquefier
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10.1007/s00016-014-0127-7
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2014-03-01
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This paper presents results from a comparative study of machining of Ti6Al4V alloy under dry, minimal quality lubrication, and cryogenic cooling conditions using coated tools at varying cutting speeds and feed rates. The influence of the cooling conditions on surface integrity and the product performance was studied in terms of surface roughness, metallurgical conditions, including microstructure, hardness, grain refinement, and phase transformation of the machined product. Results show that cooling conditions affect surface integrity of the product signifying the benefits of cryogenic cooling in improving the overall product performance.
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The effects of cooling conditions on surface integrity in machining of Ti6Al4V alloy
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10.1007/s00170-013-5477-9
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2014-03-01
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The elastic properties of $$\eta\hbox{-Fe}_2\hbox{C}$$ η -Fe 2 C (eta carbide) have been determined from ab initio density functional theory calculations using the generalized gradient approximation. The isotropic polycrystalline elastic modulus of $$\eta\hbox{-Fe}_2\hbox{C}$$ η -Fe 2 C has been calculated as the average of anisotropic single-crystal elastic constants determined from the ab initio simulations. The calculated polycrystalline elastic modulus was used to compute the elastic modulus of a case carburised gear steel subjected to shallow cryogenic treatment (SCT) and deep cryogenic treatment (DCT). This value was then compared with experimental values obtained from nanoindentation. The results confirmed that the changes in elastic modulus observed in the DCT steel can be attributed to the precipitation of $$\eta\hbox{-Fe}_2\hbox{C}$$ η -Fe 2 C . No changes in hardness have been observed between the SCT steel and the DCT steel. These data were then used to assess the surface contact fatigue behaviour of the SCT and DCT steels tested under elastohydrodynamic lubrication conditions.
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Elastic properties of eta carbide (η-Fe_2C) from ab initio calculations: application to cryogenically treated gear steel
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10.1007/s10853-013-7942-0
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2014-03-01
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Blinking (stochastic intermittence) of fluorescence is a quite common phenomenon that accompanies the emission of single quantum objects-organic chromophore molecules, quantum dots, and nanocrystals. It is demonstrated that fluorescence blinking of single organic molecules embedded into a polymer matrix including the occurrence of “grey” states is due to tunneling transitions in the two-level systems (TLSs) of the matrix. The repeated registration of fluorescence excitation spectra of single molecules (SMs) is used for our analysis. The statistics of fluorescence blinking of an SM is directly related to conformational changes (tunneling transitions in TLSs) in its immediate vicinity. Individual parameters of the corresponding elementary excitation are also determined.
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Manifestation of tunneling TLS dynamics of a polymer matrix in single-molecule fluorescence blinking
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10.3103/S1062873814030150
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2014-02-01
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An experiment to calibrate temperature sensors at cryogenic temperature has been performed. The main objective of this study was to develop a precise instrument for calibrating the temperature sensors over a temperature range of 4 K to approximately room temperature without liquid helium. The instrument consists of radiation shields, a sensor block, an electric heater, a cryocooler and a vacuum chamber. In a vacuum chamber, the cold head of the cryocooler is thermally anchored to the sensor block to bring the apparatus to a desired temperature. An electric heater is placed at the second stage of the cryocooler to control the temperature of the sensor block. The entire apparatus is covered by radiation shields and wrapped in multi-layer insulation to minimize thermal radiation in a vacuum chamber. The dimensions of components including instrumental wires are optimized to reduce total heat invasion from room temperature into cryogenic temperature. The vacuum chamber is pumped down and cooled to cryogenic temperature by a cryocooler. The resistance of each temperature sensor is measured at steady state as well as cooling down and warming up cycles, and the performance of calibration is discussed with respect to the sensitivity and resolution.
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Development of variable temperature instrument for sensor calibration
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10.1007/s12206-013-1140-5
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2014-02-01
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Three improved ^13C-spinlock experiments for side chain assignments of isotope labelled proteins in liquid state are presented. These are based on wide bandwidth spinlock techniques that have become possible with contemporary cryogenic probes. The first application, the H(C^aliC^aro)H-TOCSY, is an HCCH-TOCSY in which all CH_n moieties of a protein are detected in a single experiment, including the aromatic ones. This enables unambiguous assignment of aromatic and aliphatic amino acids in a single, highly sensitive experiment. In the second application, the ^13C-detected C^all-TOCSY, magnetization transfer comprises all carbons—aliphatic, aromatic as well as the carbonyl carbons—making the complete carbon assignment possible using one spectrum only. Thirdly, the frequently used HC(CCO)NH experiment was redesigned by replacing the long C-carbonyl refocused INEPT transfer step by direct ^13C–^13C-TOCSY magnetization transfer from side chain carbons to the backbone carbonyls. The resulting HC(CCO)NH experiment minimizes relaxation losses because it is shorter and represents a more sensitive alternative particularly for larger proteins. The performance of the experiments is demonstrated on isotope labeled proteins up to the size of 43 kDa.
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Improved NMR experiments with ^13C-isotropic mixing for assignment of aromatic and aliphatic side chains in labeled proteins
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10.1007/s10858-013-9808-9
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2014-02-01
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Electron beam welding of pre-aged cast 718 produced a slender Laves phase, while welds from solutionized cast 718 exhibited a blocky Laves phase with an initial stage of δ precipitation and formation of γ′+γ″ strengtheners after post weld heat treatment (PWHT). The presence of primary strengthener and coarse Laves particles in PWHT weld may cause reduction of the micro-plastic zone ahead of a crack, leading to a significant decrease in Charpy impact toughness at 77 K (−196 °C).
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Effect of Post Weld Heat Treatment on Cryogenic Mechanical Properties of Electron Beam Welded Cast Inconel 718
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10.1007/s11661-013-2133-9
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2014-02-01
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Escalation in food industries unctuous wastes has led to serious anthropogenic problems to the environment. Parallel to “green strategy”, growing awareness in biological treatment emphasizes efficacy of enzymatic technology for bioremediation. Pertinently, researchers are in search for new lipase-lipid interaction for improved outcome. Rhodococcus species have documented inadequate evidences on lipase enzyme production. Consequent assessments on Rhodococcus isolates from Peninsular Malaysia have identified twelve promising strains as lipase producer. Interestingly, apart from usual lipolytic behaviour, Rhodococcus sp. exhibited significant level of lipase endogenously, while cryogenic grinding method effectively ruptured the cell. An isolate from petroleum-contaminated site, namely Rhodococcus UKMP-5M, projected the highest level of lipase specificity and has further been optimized. It was found out that the best specificity was apparent in acidic condition (pH 5) with 6% inoculum at 30°C for 72 hours of incubation. Due to high level of mycolic cell-surfactant developed in triacylglycerol supplements, cell lysis was employed with Triton X-100 detergent solubilisation. As a result, oil blend composed of various carbon-chain length fatty acids (composite 2) induces enzyme production extensively. Remarkably, R. UKMP-5M found to cater enzyme production without aid of inducer by nature, but additional carbon source like glucose represses lipase production. Further ability for biological treatment was revealed when the optimized R. UKMP-5M whole cell degraded waste cooking oil significantly by solubilizing fatty acids and commencing conversion into biomass. These qualities resemble practical new lipid-lipase biological lipid rich on-site treatment.
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Rhodococcus UKMP-5M, an endogenous lipase producing actinomycete from Peninsular Malaysia
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10.2478/s11756-013-0308-x
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2014-01-01
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Cryogenic landslides are the main relief-forming process on the Northern part of West Siberian Plain. This chapter discusses the theory of cryogenic landslides and suggests classification method based on mechanisms, specific landforms—manifestations of various landslide processes. The study is based on the long-term field observations at Research station “Vaskiny Dachi” in Central Yamal, as well as occasional observations in other areas. Two main types of cryogenic landslides were distinguished based on mechanism and mode of displacement. They are (1) earth/mud flows (retrogressive thaw slumps) and (2) translational landslides (active-layer detachments). The first type results from thawing of massive ground ice within permafrost layers, while the second type is caused by the thawing of ice lenses in the active-layer base (transient layer). Distinguished are specific landforms: (1) thermocirques, and (2) landslide cirques. Landslide cirques are considered to start at a subsequent stage of thermocirque after the massive ground ice layer is exhausted or buried by landslide masses. The thermocirque changes are noted within years and decades, while new landslides within landslide cirques are separated by several centuries. As landslide masses bury organic material of soil and vegetative canopy, it is possible to use radiocarbon dating method to know the age of the landslides. Shear surfaces of ancient landslides are overgrown by abnormally high willow shrubs which allow the use of dendrochronologic method in the analysis of landslide cirque development.
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Cryogenic Landslides in the West-Siberian Plain of Russia: Classification, Mechanisms, and Landforms
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10.1007/978-3-319-00867-7_11
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2014-01-01
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A cryogenic system for cooling samples in an IMS-4F secondary-ion mass spectrometer with a static analyzer is described. The cryogenic system allows maintenance of the sample temperature with an accuracy of ±1 K in a temperature range of 60–420 K by combining heating and cooling (by using liquid helium or nitrogen). The effect of the sample temperature (300 and 110 K) on the secondary-ion mass spectra of Si and GaAs samples is considered.
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A cryosystem for cooling samples in a secondary-ion mass spectrometer with a static analyzer
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10.1134/S0020441214010102
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2014-01-01
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This chapter presents an assessment of cryogenic landslide hazard study based on differentiation of landscapes in Central Yamal. Analysis of landslide pattern shows that all recent cryogenic landslides are located on concave slopes. As concave slopes from our opinion are being modified from ancient landslides, it means that recent landslides occupy ancient landslide slopes. Recent landslide impact differs within the same landscape complexes appearing on different geomorphic levels of the central Yamal. Generally, this impact increases from low to high geomorphic levels. Landscape complexes are divided into five groups according to predicted cryogenic landslide hazard degree. Grouping of landscape complexes is based on differentiation of landscape conditions more or less favourable for cryogenic landslides and on the latest cryogenic landslide occurrence. Landslide distribution within a landscape unit determines its sensitivity to landslide recurrence; the larger the area of disturbance by recent landslide, the more sensitive is a landscape complex subdivided within the study site. At the same time, directly disturbed by the latest landslides areas within a landscape unit are considered non-hazardous because the re-occurrence of cryogenic landslides on such locations in coming centuries is mostly improbable.
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Assessment of Landslide Hazards in a Typical Tundra of Central Yamal, Russia
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10.1007/978-3-319-00867-7_20
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2014-01-01
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In this chapter useful tables containing data of thermal contraction below room temperature of several materials, most of them used in cryogenic applications, are reported together with the coefficient of thermal expansion at 293 K. The values of thermal contraction are referred at the length of the sample at 293 K.
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Data of Thermal Expansion
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10.1007/978-94-017-8969-1_6
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2014-01-01
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Interrelation between the height and productivity of willow tundra, and activation of cryogenic landsliding is discussed. Cryogenic landslides on saline marine sediments in Typical tundra subzone of the Yamal Peninsula show specific features. Landslide process causes desalinization of marine sediments and enriches the active layer with salts. Landforms of the landslide-affected slopes can serve as indicators of permafrost table change, heterogeneity of saline composition of near-surface sediments. It is suggested that high willow canopies are indicators of ancient landslide activity. Landslide-affected slopes significantly differ by structure of phytomass from stable surfaces (background): on landslide slopes willow proportion in phytomass reaches 50–80 %, while background surfaces are dominated by moss (60–70 %). The total aboveground phytomass on ancient landslides (an average of about 1,600 g/m^2) is much higher than on stable surfaces (an average of about 1,200 g/m^2). Most informative landslide age indicators are: salinity of sediments and ground water, macro- and trace-element concentration, ash content in willow leaves and grasses. Concentration of chemical elements can either increase with age, or decline. This is obviously due to the mobility of an element migrating in the active layer.
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Study of Plant-Soil-Permafrost System on Landslide-Affected Slopes Using Geochemical Methods on Yamal, Russia
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10.1007/978-3-319-04996-0_80
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2014-01-01
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Natural conditions along the route of the arterial gravity-flow Tuora-Kyuel’ – Tatta Canal in Central Yakutia are examined. Characteristics of the grain-size distribution and cryogenic structure of the frozen soils, and the velocity of the water flow are isolated for prediction of washout (thermal erosion).
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Cryogenic structure of frozen soils and thermal erosion in zone of arterial canal
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10.1007/s10749-014-0446-5
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2014-01-01
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Active layer detachment slides of different age were examined in the Central part of Yamal peninsula (West Siberian Arctic) in the subzone of northern hypoarctic tundra. Plant communities on the shear surface, on displaced blocks with preserved but degrading initial tundra vegetation and on undisturbed surroundings were described. In the processes of recovery pioneer grass-dominated communities on relatively dry surfaces and Equisetum-dominated communities in wet cracks were replaced by Salix reptans-graminoid communities. Vegetation on displaced blocks also transformed to the similar communities. On the oldest completely recovered landslides Salix reptans–graminoid communities with thin moss stratum occur both on former shear surface and on washed out remnants of blocks. Ancient landslides are indicated by willow copses and mesophytic herbaceous communities.
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Dynamics of Vegetation on Cryogenic Landslides of Different Age in Central Yamal (West Siberian Arctic)
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10.1007/978-3-319-04996-0_73
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2014-01-01
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Our picture of the universe, we could argue, is much more advanced than that of our ancestor’s model of the universe. However, our simulations can crumble when we learn about the unknown. Among those unknowns in our universe are two constituents that make our understanding of the universe as fragile as that of our precursors. Dark energy and dark matter are synonyms of our ignorance, so to speak. Nonetheless, we have made tremendous progress in last several years to grasp these unknown forces that shape the future of our universe. While we celebrate our scientific advancement that has been made over centuries, dark energy and dark matter teach us to be humble.
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Dark Forces in the Universe
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10.1007/978-3-319-01887-4_6
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2014-01-01
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Improved adsorbent types and compositions have been developed for the challenging separation of the ortho - and para -hydrogen spin isomers at 77 K. From a systematic study of commercially available adsorbent types, it has been found that zeolites of type X offer the largest capacity and selectivity towards ortho -hydrogen and that performance is significantly impacted by the cation type and the number of cations present in the zeolite. For the present separation improved performance was obtained with larger Group I cations, especially K and Cs. Another key property of the adsorbents addressed in the present work is the need to control the adsorbent composition to avoid unwanted catalytic conversion of the para - to ortho -hydrogen. A common source of unwanted catalytic activity in many adsorbent compositions was identified as the presence of unwanted transition metal impurities, especially iron associated with the natural clays, commonly employed as binding agents in the commercial agglomerated zeolite products. To avoid this, equivalent adsorbent compositions were agglomerated instead using colloidal silica binding agents which successfully minimize back conversion of the para - to ortho -hydrogen and produced adsorbents with higher capacities and selectivities for the ortho component at the test temperature of 77 K. These advanced adsorbents can be applied in more efficient hydrogen liquefaction processes.
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Advanced adsorbents for the separation of the ortho- and para-hydrogen spin isomers at cryogenic temperatures
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10.1007/s10450-013-9561-0
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2014-01-01
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The paper is discussing the theory of cryogenic landslides. Suggested is classification of cryogenic landslides based on several attributes: mechanisms, specific landforms, and other manifestations of landsliding characteristic of the Arctic plains of Russia. The theory results from long-term field study at research station “Vaskiny Dachi” in Central Yamal, key sites on Yugorsky peninsula, as well as occasional observations in other areas of the Russian Arctic. Two main types of cryogenic landslides are identified: retrogressive thaw slumps (earth/mud flows) and translational landslides (active-layer detachments). Distinguished are several stages of landform development resulting from landsliding, passing from thermocirques to landslide cirques. Landslide cirques are considered to start as a subsequent stage of decadent thermocirque after the ground ice layer is exhausted or buried by landslide masses. Cryogenic landslides are climate-related features and for this reason are indicators of past and modern climate fluctuations.
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Cryogenic Landslides in the Arctic Plains of Russia: Classification, Mechanisms, and Landforms
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10.1007/978-3-319-04996-0_75
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2014-01-01
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One of the topical issues arising due to the development of natural resources and the climate change in the Arctic Region is the prediction of ecosystems’ dynamics, based on the study of tundra biota response to the different natural and anthropogenic impacts. The cryogenic landslides’ process appears to be one of the determining factors of the ecotopes’ transformation in the various tundra regions including the Central Yamal. The process is influencing vegetation of vast areas, its structure and dynamics. The structure of plant communities is an important factor of the cryogenic landslides’ activation. The ecotopes of the later vegetation demutation stages’ communities are the most resistant to the development of the process. These communities have a closed shrub cover of Salix glauca (that is often 1–1.5 m high). At the subclimax stage this cover gets thinned, and the mosses begin to dominate by the phytomass. In subclimax communities there are no plants with extensive root systems capable to “retain” the structure of the active layer; therefore their ecotopes turn out to be extremely non-resistant to the development of the landslide process. Geochemical processes proceeding in the active layer also lead to the ecosystem destabilization through slow accumulation of secondary clay minerals on the border between active layer and permafrost. These minerals play a significant role in cryogenic landslides’ development. The strain in upper deposits’ horizons, which is also necessary for the landslide process activation, is accumulated gradually.
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Vegetation Dynamics of Landslide Affected Slopes (Central Yamal)
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10.1007/978-3-319-04996-0_68
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2014-01-01
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A series of reciprocating wear tests were performed on the deep cryogenically treated and conventionally heat-treated samples of 100Cr6 bearing steel to study the wear resistance. The worn surfaces as well as the wear debris were analyzed by scanning electron microscopy. The improvement in wear resistance of the deep cryogenically treated samples ranges from 49% to 52%. This significant improvement in wear resistance can be attributed to finer carbide precipitation in the tempered martensitic matrix and the transformation of retained austenite into martensite. X-ray diffraction analysis shows that the volume fraction of retained austenite in the conventionally heat-treated samples is 14% and that of the deep cryogenically treated samples is only 3%.
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Influence of cryogenic treatment on the wear characteristics of 100Cr6 bearing steel
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10.1007/s12613-014-0863-3
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2014-01-01
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Successful development of amorphous solid dispersion formulations depends on three primary factors: active pharmaceutical ingredient properties, stabilizing polymer, and the processing technology. Polymer provides the fundamental framework for stabilizing the amorphous form and the process supplies the energy required to transform the system into an amorphous form. This is evident from ample examples where simply physical mixing of the amorphous drug and polymer did not provide satisfactory outcome in terms of either improving the solubility or enhancing the bioavailability. Effectiveness of the process is critical to generate, capture, and preserve the amorphous form. The success of these processes is dependent on the process time and the supersaturation conditions that are being generated during the formation of the solid dispersion. From the discovery of solid dispersions in the early 1960s, the application of solid dispersion concept to solve solubility challenges in real world was limited and this was partly due to the lack of commercially viable processing technologies. However, in the past two decades this area has seen remarkable progress as the science and understanding of the manufacturing technologies, specifically spray drying and melt extrusion, have evolved considerably leading to several commercially successful amorphous products in addition to numerous in development. Besides advancing the field and scientific understanding, many technology-driven companies have thrived in this environment by enabling the development of poorly water-soluble drugs that would have otherwise been dropped from consideration. Spray drying and hot-melt extrusion have become the backbone of amorphous formulations in the pharmaceutical industry while newer technologies are constantly being added to the tool box that promise to improve quality, productivity, and/or better performance of the products. Having access to multiple technologies tremendously increases the probability of success for a large variety of compounds. The choice of technology is primarily governed by the physicochemical properties of the drug substance, availability of technology from lab scale to commercial scale, robustness of the process, product performance, and lastly the impact of the selected technology on the cost of goods.
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Overview of Amorphous Solid Dispersion Technologies
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10.1007/978-1-4939-1598-9_3
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