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2021-01-01
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The research effort in high entropy alloys (HEAs) has intensified in the recent years. This is due to the fact that HEAs have a wide range of compositions based on elements used, the number of different elements in a system and the sheer number of compatible elements that exist. HEAs exhibit broader range of superior mechanical and microstructural properties, and this fact points toward many potential applications. The aim of this research is to unify and present the multiple streams of research efforts which have impacted the understanding of HEAs. The information has been included based on its dominant focus areas. Article has been categorized into important aspects based on its effect on the mechanical properties of the alloys. The effect of element compositions, treating conditions and processes on microstructural and mechanical properties has been also considered. In future, better methods and newer technologies will definitely result in better and more reliable materials which will supersede some of the previously existing materials.
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Effect of Various Aspects on Mechanical Properties of High Entropy Alloys: A Review
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10.1007/978-981-33-6029-7_28
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2021-01-01
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This research work is to explicit the surface morphology, material composition and crystal structure of a closed-cell aluminium foam subjected to various treatments such as heat treatment (HT), cryogenic treatment (CT) and cryogenic heat treatment (CHT). The closed-cell aluminium foam utilized for this research is made of Al 6101 aluminium alloy with high purity. The microstructure, material composition and crystal structure of the treated samples are evaluated by a high-resolution scanning electron microscope, energy dispersive X-ray technique and X-ray diffraction technique, respectively. From the results, significant observations were made in the surface morphology of the Al 6101 foam samples subjected to various treatments.
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The Effect of Novel Cryogenic Treatment in the Microstructure Analysis of Al 6101 Closed-Cell Foam
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10.1007/978-981-33-6428-8_2
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2021-01-01
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In Chap. 9 , we showed an example of hydration-coupled conformational changes Hydration-coupled conformational change . However, the energy landscape Energy landscape of protein motions including hydration changes remains unexplored. As a future approach to understanding how motions of hydrated proteins occur in solution, here we examine methods of structural analysis that can be used to collect a large number of protein conformations, including their hydration structures Hydration structure , that are necessary for describing the free-energy landscape Free-energy landscape . Particularly, a set of equations for cryogenic electron microscopy Electron microscopy images and molecular dynamics snapshots Snapshot are derived and applied to illustrate the energy landscape Energy landscape of protein domain motion Domain motion . Using artificial intelligence-based prediction of hydration structures Prediction of hydration structure , conformational transition in the energy Energy landscape, will be illustrated.
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Energy Landscape and Hydration of Proteins
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10.1007/978-4-431-56919-0_10
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2021-01-01
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Abstract A numerical model of the evolution of the trench profile during cryogenic etching in SF_6/O_2 plasma based on the cellular representation of the surface state, the Monte Carlo method for calculating particle fluxes, and the scheme of delayed desorption of reaction products is proposed. This description combines the advantages of the cell method (the ability to describe phenomena of a stochastic nature) and the string method (parameterization of the model in terms of physically observable quantities). The consistency of the model for etching silicon and silicon oxide in a fluorine-containing plasma, as well as etching in a SF_6/O_2 mixture at different temperatures is demonstrated. Spontaneous etching of silicon under the action of fluorine radicals, ion-stimulated etching, surface passivation in plasma containing oxygen radicals are simulated. A model that describes the temperature dependence of the etching character is proposed.
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Numerical Simulation of Cryogenic Etching: Model with Delayed Desorption
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10.1134/S106373972101008X
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2020-12-01
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This paper presents a novel indirect cryogenic cooling system, employing liquid nitrogen (LN_2) as a coolant for machining the difficult-to-cut ASTM F-1537 cobalt-chromium (CoCr) alloy. The prototype differs from the already existing indirect cooling systems by using a modified cutting insert that allows a larger volume of cryogenic fluid to flow under the cutting zone. For designing the prototype analytical and finite element, thermal calculations were performed; this enabled to optimize the heat evacuation of the tool from the rake face without altering the stress distribution on the insert when cutting material. Turning experiments on ASTM F-1537 CoCr alloys were performed under different cutting conditions and employing indirect cryogenic cooling and dry machining, to test the performance of the developed system. The results showed that the new system improved surface roughness by 12%, and cutting forces were also reduced by 12% when compared with the existing indirect cryogenic cooling technique.
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A novel indirect cryogenic cooling system for improving surface finish and reducing cutting forces when turning ASTM F-1537 cobalt-chromium alloys
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10.1007/s00170-020-06193-x
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2020-12-01
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Abstract The development of advanced technologies includes the development of new materials, which include composite amorphous nanocrystalline materials characterized by a unique combination of magnetic and mechanical properties (the latter include high strength, hardness, and wear resistance and others). However, the potential for using such materials is limited, since they are relatively quickly embrittled (lose their plasticity) even at room temperature. The properties of plasticity cannot be restored by heat treatment of the amorphous phase. It is found that properties of plasticity can be restored using thermal cycling in the interval between the temperature of liquid nitrogen (77 K) and room temperature (295 K). This process of treatment is called rejuvenation; it turns out to be acceptable only for bulk samples obtained in the form of rods. It is not suitable for samples in the form of ribbons with a thickness of 20–50 μm (the vast majority of amorphous alloys are obtained in this form). A modernized technology for treating such samples of amorphous alloys and partially crystalline alloys using cryogenic thermocycling is presented. This technology allows one to restore the amorphous structure and plasticity of thin ribbons. X-ray diffraction patterns of ribbon samples of alloy Al_87Ni_8Gd_5 pre-annealed at a temperature of 170°C with the fraction of the nanocrystalline phase not exceeding 10% before and after several successive cooling/heating cycles show that the amorphous structure of the initial sample can be completely restored by increasing the number of cycles to two hundred.
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Restoration of the Structure of Amorphous Alloys and Partially Crystalline Alloys Using Cryogenic Thermocycling
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10.1134/S0020168520150029
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2020-12-01
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A new stretched-wire system is built for a cryogenic permanent magnet undulator in High Energy Photon Source Testing Facility. The system has two functions: integral field measurement and magnet gap measurement. Integral field measurement and gap measurement are important for evaluation and optimization of the magnetic performance of the undulator in cryogenic–vacuum environment. Two high-precision, high-load motion stages are used for accurate positioning. A special fix structure of stretched wire is adopted for vacuum environment. To reduce the deflection of the 3-meter-long wire, constant tension is maintained along the wire. The measurement repeatability of field integral and magnetic gap is the key performance which depends on the stability of wire and suppression of the electric noise. Strategy of improving the measurement accuracy and stability is presented.
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High-accuracy stretched-wire measurement system for cryogenic permanent magnet undulator (CPMU) in High Energy Photon Source (HEPS)
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10.1007/s41605-020-00204-x
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2020-12-01
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The application of cryogenic treatments is gradually increasing in tool steels. In this sense, these heat treatments can modify the mechanical properties of high chromium alloy steels. However, the influence of the cooling parameter (during quenching) is often neglected. This investigation aims at evaluating the effects of cooling parameter and cryogenic treatment on microstructure and fracture toughness of AISI D2 tool steel. The cooling parameter ( λ ) was defined as the cooling time from 800 to 500 °C divided by 100. During quenching, different cooling parameters ( λ 1 = 2.8 and λ 2 = 1.8) were employed, and the samples were tempered three times or, besides, cryogenically treated by a single tempering. Later, the samples were evaluated through phase analyses and their proportions, sizes, and distribution of carbides by optical and scanning electronic microscopy, hardness measurements, x-ray diffraction, and fracture toughness tests. For the λ 2 cooling parameter followed by cryogenic treatment, the results presented an increase of 51% over the initial condition of secondary carbides. However, the higher hardness values were found in the λ 1 cooling parameter followed by cryogenic treatment. In the fracture toughness evaluation, a reduction of 8% in K _IC was observed for samples with cryogenic cycles compared to the samples without it.
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Effects of Cooling Parameter and Cryogenic Treatment on Microstructure and Fracture Toughness of AISI D2 Tool Steel
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10.1007/s11665-020-05285-9
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2020-12-01
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Cryogenic cooling helps to improve the machining performance and reduce the tool wear. Cryogenic condition could activate these substructures such as deformation twins and dislocation cells. The effects of the substructures are not taken into consideration in the conventional machining models. The conventional models cannot characterize the dynamics in cryogenic machining, i.e., the evolutions of cutting force and temperature with time. Here, considering the effect of the substructures, a new analytical model for metal cutting was proposed to predict the dynamics in cryogenic orthogonal machining. To validate the applicability of the proposed model, the experiments of orthogonal cutting copper at liquid nitrogen temperature and room temperature were conducted. Transmission electron microscope observations show that nanotwins formed in cryogenic cutting copper. The comparisons between experimental cutting forces and the proposed model or the conventional models validate the rationality of the nanotwin-based analytical model. Numerical calculations were further carried out to reveal the underlying mechanism. The periodic oscillation of cutting force in liquid nitrogen condition is a phenomenon of Hopf bifurcation resulting from the formation of nanotwins. Graphical Abstract
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A nanotwin-based analytical model to predict dynamics in cryogenic orthogonal machining copper
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10.1007/s00170-020-06303-9
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2020-12-01
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Abstract —The purpose of this work was to study the possibility of obtaining nanocellulose (NS) by ultrasonic (US) processing of powdered cellulose in a medium of liquid nitrogen (LN). To achieve this goal, it was necessary to determine the effect of the time of ultrasonic treatment in the medium of LN on the dispersed composition, crystallinity index and degree of polymerization (DP) of cellulose samples. Studies were performed using a powder X-ray diffractometer, a laser particle analyzer, and a scanning and transmission electron microscope. The DP of cellulose was determined by the viscosity of its solution in cadoxene by the standard method. It has been found that cryogenic grinding of flax cellulose samples does not lead to significant changes in its structural modification and degree of crystallinity, which indicates the high resistance of this material to such effects. However, ultrasonic exposure in the medium of LN with the subsequent treatment with 25, 45, 65% H_2SO_4 allows us to obtain cellulose nanospheres with a diameter of 48 to 437 nm and a yield of up to 40%. Unlike other types of nanoparticles (nanofibrillar, nanocrystalline cellulose), cellulose nanospheres have a larger surface area, which opens up the possibility of their effective use for the modification of composite materials.
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Preparation of Nanocellulose from Nonwood Plant Raw Materials
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10.1134/S1068162020070109
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2020-12-01
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Abstract This work summarizes the archived data of geocryological and hydrogeological conditions in the west of Nordenskiold Land on the Spitsbergen Archipelago. The historical data obtained in the Soviet period during coal exploration are reviewed together with the results of our own studies performed as part of the Russian Scientific Arctic Expedition on Spitsbergen (RAE-S) in 2016–2020. With respect to geocryology, the region is assigned to the zone of continuous permafrost. The thickness of rocks and sediments with temperatures below zero is about 100 m near the coast and increases to 540 m on watersheds. The mean annual ground temperature near the zero-amplitude depth varies from –3.6 to –2.2°C. Below this layer, the temperature curve in the top part of the section tends to deviate toward positive temperatures, reflecting the modern cycle of climate warming. From the hydrogeological point of view, the area belongs to the marginal zone of the West Spitsbergen cryoadartesian basin. Seawater intrusions near the coast form saline subpermafrost aquifers, including those with temperatures below zero, reflecting the seawater (sodium chloride) composition and hydraulic heads close to sea level. Fresh and slightly saline (sodium bicarbonate on the east coast of Grønfjorden and magnesium–calcium sulfate in gypsum-bearing deposits on the west coast) subpermafrost water with hydraulic heads reaching 100 m above sea level is fed by water-saturated ice in the deep layers of large glaciers.
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Geocryological and Hydrogeological Conditions of the Western Part of Nordenskiold Land (Spitsbergen Archipelago)
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10.1134/S000143382011002X
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2020-12-01
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Abstract— The origins of detrimental strains up to the destruction of parts and assembly units of mechanical facilities and outfits in contact with shape-memory alloys are considered. The characteristics of safe operations with shape-memory alloys, which can turn out of shape by themselves with significant strength parameters under certain conditions, are presented, as are the technological characteristics of using these alloys, with cryogenic liquids included.
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Characteristics of Safety Precautions for Processing Shape Memory Alloys, Including at Cryogenic Temperatures
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10.3103/S1052618820080154
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2020-12-01
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AA2014 is a high-strength Al-Cu alloy which is used for highly stressed components in aircraft fuselage, wing covers and military truck frames due to their excellent strength-to-weight ratio, and its properties are usually enhanced by further heat treatment. In this work, the conventional heat treatment process is replaced with shallow cryogenic treatment (SCT) with eight different soaking hours for enhancing the mechanical properties and followed by a tempering process at 160 °C for 18 h. The dislocation effect due to SCT produces volume contraction and grain rotations and shrinking the vacancies and micropores, present in the matrix. Due to the metallurgical behaviour of the strengthening precipitates Theta(θ) phase (CuAl_2) and the insoluble particles which are finely dispersed along the grain boundaries of the matrix during the tempering process, results in higher tensile strength, % elongation and fracture toughness. The maximum percentage improvement in microhardness, ultimate tensile strength, % elongation, fracture toughness and wear rate are 40%, 1.28%, 10%, 23% and 48%, respectively, for 18 h of shallow cryogenic treatment, and the property varies for different soaking hours. With these improvements, AA2014 can provide better mechanical properties than the recently developed aluminium alloys with reduced cost.
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Effect of Cryogenic Treatment on Mechanical Properties of Aluminium Alloy AA2014
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10.1007/s40033-020-00237-y
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2020-12-01
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Abstract The compact models of junction field effect transistors (JFETs) used in release-quality versions of SPICE-like programs are focused only on the standard temperatures ranging from –60 to 150°C and are unworkable for an electronic circuit design in the cryogenic temperature range (below –120°C). It this study, the Low-T SPICE model of the JFET for designing electronic circuits in the extended temperature range, including the cryogenic range (from –200 to 110°С), is proposed. The model takes into account the changes in the I–V curves caused by the effect of ultralow temperature: growth of the saturation voltage V _ D sat, decrease of the pinch-off current I _p and steepness BETA , negative slope LAMBDA of the output I–V curves, increase of the drain–source resistance RD as the result of the freezing effect, etc. For this purpose, the dependences of the specified parameters on temperature are introduced in the model. The procedure for extracting the SPICE parameters of the Low-T SPICE model of the JFET is developed according to the results of the measurements of the standard set of the I–V curves in the cryogenic temperature range. The error of the calculation of the I–V curves is not higher than 10–15% in the temperature range from –200 to 110°C.
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The Special Features of Simulation of the Current–Voltage Characteristics of JFETs in the Cryogenic Temperature Range
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10.1134/S1063739720070070
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2020-11-28
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To improve the machining performance manufacturers adopt various methods to improve the tool life which influences production cost and the degree of the surface finish. Recently cryogenic treatment is used to improve the machining performances. In the present work, the tungsten carbide-cobalt (WC–Co) cutting tool is cryogenically treated at − 196 °C for a soaking time of 24 h and tempered to 200 °C for 2 h. The machinability attributes such as Tool Wear Rate, Surface profile roughness (Ra), of the Cryo Treated (CT) cutting tool, are measured on turning operation with different parametric conditions on the Al6063 alloy and compared with an Untreated Tool (UT). The results show that the CT tool improves the tool life with an acceptable surface finish. Taguchi’s coupled multi-objective optimization methods such as Grey Relational Analysis (TC-GRA) and Technique for Order Preference by Similarity to Ideal Solution (TC-TOPSIS) were actualized to enhance the turning performance of CT tool. The outcomes revealed that TC-TOPSIS acquired ideal condition is improving the exhibition than the TC-GRA. Furthermore, the interaction impact of cutting parameters is analyzed through 3D surface plots.
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Studies on the effects of deep cryogenic treated WC–Co insert on turning of Al6063 using multi-objective optimization
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10.1007/s42452-020-03940-3
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2020-11-01
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This work evaluates the machinability improvements in vastly used titanium alloy (Ti-6Al-4V) using alternate turning techniques. Detailed examination of flank and crater faces of inserts is carried out in this work to analyze tool wear under dry, wet, and cryogenic environments. Critical responses such as crater wear and energy consumption decide the machinability of materials, but these responses are less explored in the past using altered cutting conditions. This investigation analyzes the machinability in terms of industry-relevant responses such as tool wear, energy consumption, chip reduction coefficient, and average surface roughness under altered cutting conditions. Outcomes of this investigation show increase in tool life by 200% and 80% using cryogenic turning than in dry and wet turning techniques, respectively. Moreover, the findings of the study show up to 9% and 61% decline in energy consumption using cryogenic turning than in dry and wet turning, respectively. Surface roughness values also show a reduction by up to 71% and 64%, under cryogenic environment than in dry and wet environments, respectively. The results of this study advocate the suitability of cryogenic turning at industry-relevant parameters to establish this technique as a viable alternative to replace inefficient conventional turning techniques.
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Tool wear progression and its effects on energy consumption and surface roughness in cryogenic assisted turning of Ti-6Al-4V
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10.1007/s00170-020-06140-w
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2020-11-01
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The stress corrosion cracking (SCC) susceptibility of 316L austenitic stainless steel milled with cryogenic cooling and conventional cutting fluid cooling is investigated and compared. The milled subsurface properties are characterized in terms of microstructure, residual stress and microhardness. The SCC susceptibility of the milled surfaces is evaluated in boiling MgCl_2 by examining the density and depth of the SCC microcracks. Results show that the cryogenic milling increases the SCC susceptibility of 316L austenitic stainless steel. The increase of SCC susceptibility is attributed to the higher residual tensile stress level and the larger volume fraction of slip band produced in the cryogenic milling process in comparison with the conventional cooling milling.
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Effects of Cryogenic Milling on Stress Corrosion Cracking Resistance of AISI 316L Austenitic Stainless Steel
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10.1007/s11665-020-05190-1
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2020-11-01
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Over the last decade, quantum computing has experienced significant changes and captured worldwide attention. In particular, superconducting qubits have become the leading candidates for scalable quantum computers, and a number of cryogenic materials have scientifically demonstrated their potential uses in constructing qubit chips. However, because of insufficient coherence time, establishing a robust and scalable quantum platform is still a long-term goal. Another consideration is the control circuits essential to initializing, operating and measuring the qubits. To keep noise low, control circuits in close proximity to the qubits require superior reliability in the cryogenic environment. The realization of the quantum advantage demands qubits with appropriate circuitry designs to maintain long coherence times and entanglement. In this work, we briefly summarize the current status of cryogenic materials for qubits and discuss typical cryogenic circuitry designs and integration techniques for qubit chips. In the end, we provide an assessment of the prospects of quantum computers and some other promising cryogenic materials.
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Cryogenic Materials and Circuit Integration for Quantum Computers
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10.1007/s11664-020-08442-x
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2020-11-01
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The modulation transfer function (MTF) is one of the key figures of merit for the characterization of infrared focal plane arrays (FPA). Moreover, with both the trend of reduced pixel pitch and the variety of pixel structures observed in the industry, the study of the impact of wavelength on the MTF is also of great interest, and thus needs a spectro-spatial measurement. In this paper, we demonstrate such spectral MTF measurements in the mid-wavelength infrared (MWIR) band by the use of several spectral bandpass filters. We realize those measurements at 80 K on a specific n / p 320 × 256 HgCdTe MWIR FPA, divided into different areas. The pixel pitch is the same for all areas (30 μm), the only difference being the fill factor, which differs from one zone to another. The MTF measurement bench is based on a continuously self-imaging grating interferometer integrated in a specific cryogenic set-up.
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Development of a Cryogenic Test Bench for Spectral MTF Measurement on Midwave Infrared Focal Plane Arrays
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10.1007/s11664-020-08388-0
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2020-11-01
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Manufacturing sectors are observing for methods to mitigate the use of cutting fluids for economic and ecological causes. The approach of cryogenic cooling looks to be an effective solution to enrich the process sustainability, as it is non-toxic and substantially increases the life of the tool. In this present research, milling experiments were performed to examine the surface aspects in the machining of Nimonic-80A using PVD-TiAlN/TiN-coated tool under various speed–feed combinations and nozzle orientation of 45°. Cryogenic carbon dioxide in machining enhances the quality of the newly machined face, and the outcomes were correlated with minimum quantity lubrication (MQL) and wet condition. The usage of cryogenic coolant significantly lowers the surface roughness by 38–45% and 13–18% over wet and MQL conditions. The effectiveness of cryogenic cooling curtails the contact between tool and chip, which diminishes the flank wear and chip thickness. Furthermore, it exhibits improved compressive residual stress over the other cooling strategies.
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Machining Investigation of Nimonic-80A Superalloy Under Cryogenic CO_2 as Coolant Using PVD-TiAlN/TiN Coated Tool at 45° Nozzle Angle
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10.1007/s13369-020-04728-8
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2020-11-01
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The artificial ground freezing (AGF) method has been used in many geotechnical engineering applications such as temporary excavation support, underpinning and groundwater cutoff. The AGF method utilizes a refrigerant such as liquid nitrogen or brine, circulating through embedded freezing pipes in order to freeze the ground. In this paper, two in-situ cryogenic freezing experiments (i.e., single freezing-pipe test and frozen-wall formation test) were performed using liquid nitrogen to simulate the AGF in a Korean marine clay deposit, in which the freezing rate was evaluated. The thermal conductivity of frozen and unfrozen marine clay was evaluated by performing typical laboratory experiments. In addition, the strength and stiffness of frozen-thawed deposits were comparatively measured by sounding tests (i.e., piezocone penetration test and lateral loading test). The freezing rate of the frozen-wall formation test in the Korean marine clay deposit was approximately twice as high as that of the single freezing pipe test. Compared to the original marine clay deposit, the frozen-thawed marine clay showed a significant reduction in strength and stiffness.
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Influence of In-situ Cryogenic Freezing on Thermal and Mechanical Characteristics of Korean Marine Clay
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10.1007/s12205-020-0457-8
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2020-11-01
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Magnesium alloys are identified as the new generation degradable biomaterials in the biomedical industry. They can prevent secondary operation for the removal of the inserted implant. Nowadays, sustainable manufacturing is promoting the use of low-temperature machining environments over the traditional means. Surface integrity characteristics of the machined surface and tool wear have always been some of the key interests of the researchers. In this research, aluminum titanium nitride-coated cemented carbide end mills were employed in an untreated and cryo-treated condition to machine the biomedical magnesium alloy AZ31B. The experiments were designed using one-factor-at-a-time (OFAT) approach, and milling operations were conducted under three different machining environments, namely wet, cryogenic, and hybrid. Spindle speed, feed rate, and depth of cut were chosen as the input control variables for a comparative study to achieve lowest surface roughness and highest surface microhardness. The results displayed an improvement in the outcome at higher spindle speed (2800 rpm) and lower feed rate (80 mm/rev) and depth of cut (0.5 mm) produced by untreated end mill during cryo-milling. However, the treated end mill performed best with hybrid machining environment (simultaneous application of LN_2 and cutting fluid) during milling. Moreover, in this case, the accumulated oxides were found to form the most uniform and thinnest passivation layer over the milled surface. Higher spindle speed in cryo-milling achieved 27.45 and 19.56% better surface finish than wet and hybrid-milling, respectively. Moreover, higher spindle speed in cryo-milling achieved 14.46 and 8.72% higher surface microhardness than wet and hybrid-milling, respectively. Higher spindle speed in hybrid-milling achieved 14.89 and 6.97% better surface finish than wet and cryo-milling, respectively. Furthermore, higher spindle speed in cryo-milling achieved 7.69 and 4.10% higher surface microhardness than wet and cryo-milling, respectively.
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Tailoring Surface Integrity of Biomedical Mg Alloy AZ31B Using Distinct End Mill Treatment Conditions and Machining Environments
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10.1007/s11665-020-05203-z
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2020-11-01
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The mechanical properties and corrosion resistance of selective laser melted high-strength martensitic stainless steel were enhanced by cryogenic treatment. The microstructure of the martensitic stainless steel contained fine martensite lath due to fast cooling rate. Simultaneously, there were bulk austenite formed at the boundary of molten pool and thin austenite film distributed at martensite laths. After cryogenic treatment, the content of austenite decreased from 25 to 19.2%, and Cu-rich precipitates were refined to 1-3 nm during subsequently aging due to decreasing of lattice constant, which were benefit for the hardness and tensile strength of the selective laser melted 15-5PH martensitic stainless steel without negatively influencing on the plasticity. Simultaneously, the electrochemical tests showed that the pitting potential and passivation film stability gradually increased after cryogenic treatment. Finally, the effect of cryogenic treatment on microstructure for selective laser melted high-strength martensitic stainless steel was discussed.
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Co-enhancing the Mechanical Property and Corrosion Resistance of Selective Laser Melted High-Strength Stainless Steel via Cryogenic Treatment
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10.1007/s11665-020-05237-3
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2020-10-24
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The single particle reconstruction (SPR) in cryogenic electron microscopy is considered in this paper. This is an emerging technique for determining the three-dimensional (3D) structure of biological specimens from a limited number of the micrographs. Because the micrographs are modulated by contrast transfer functions and corrupted by heavy noise, the number of micrographs might be limited, in general it is a serious ill-posed problem to reconstruct the original particle. In this paper, we propose a constrained total variation (TV) model for single particle reconstruction. The TV norm is represented by the dual formulation that changes the SPR problem into a minimax one. The primal-dual method is applied to find the saddle point of the minimax problem, and the convergence condition is given. Numerical results show that the proposed model is very effective in reconstructing the particle.
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Constrained Total Variation Based Three-Dimension Single Particle Reconstruction in Cryogenic Electron Microscopy
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10.1007/s10915-020-01344-4
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2020-10-07
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La_0.63Gd_0.37MnO_3 material was synthesized using the Pechini-modified-sol–gel method at different sintering temperatures 600, 650, 750, 800, and 900 °C. After characterizing the samples structurally and magnetically, we report a direct relation between the crystallite size, particles agglomeration level, and material performance in field-cooling/zero-field-cooling magnetization modes, in addition to an inverse relation between the existence of Griffith phase and the samples’ magneto-caloric performance. The material sintered at 800 °C presents the maximum isothermal entropy change among others that is 7.57 J kg^−1 K^−1 at 7 T, in addition to a good performance shown at higher temperatures, making it a promising candidate for different cooling applications.
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Effects of the sintering temperature on the La_0.63Gd_0.37MnO_3 structure and magnetic properties
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10.1007/s00339-020-04032-0
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2020-10-01
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Cryogenic treatment is an emerging application that can make significant changes in many materials. In this study, shallow (− 80 °C) and deep (− 196 °C) cryogenic treatment was applied to Ti6Al4V alloy. Additionally, aging treatment and supplementary deep cryogenic treatment were also performed. Tensile tests were done to observe the effects of cryogenic treatment on the mechanical properties and formability of Ti6Al4 alloy. According to the results of these tests, it was observed that the cryogenic treatment had a positive influence on the plasticity properties of Ti6Al4V alloy. For the 24-h and 36-h deep cryo-treated samples, the uniform plastic deformation region (UPDR) was extended 5 and 8.3% compared to untreated sample, respectively. However, this improvement in plasticity observed in samples treated with cryogenic treatment for 36 h led to a decrease in yield strength by 2%. Microstructural and XRD analysis was performed to characterize the microstructural changes that happened with the effect of applied heat treatments. The characterization study shows that with the application of cryogenic treatment internal structure of the material changed, the β phase ratio of the alloy decreased from 8.1 to 5.6% with 36-h deep cryogenic treatment. The unstable β phase was transformed into α phase and stable β phase. The experimental study shows that cryogenic treatment improves the plasticity and toughness of Ti6Al4V alloy at room temperature and regulates the microstructure and reduces the residual stress.
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Influence of Cryogenic Treatment on Microstructure and Mechanical Properties of Ti6Al4V Alloy
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10.1007/s11665-020-05177-y
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2020-10-01
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We propose a method for the evaluation of the flow rate of cryogenic two-phase flows in flowmeters without separation based on the Venturi tube. The proposed procedure takes into account the equations of state of two-phase medium, i.e., the changes in density, mass vapor quality, and temperature of cryogenic twophase flows depending on the level of pressure in the Venturi tube. It is shown that if we do not take into account the evolution of the parameters of flow, then we get an additional error in the evaluation of the flow rate. Hence, it is impossible to correctly determine the sensitivity and measurement range of the flowmeter. We determine the optimal range of measurements of the pressure drop and propose a procedure of measurement of the flow rate of two-phase cryogenic flows according to the temperature drop in the Venturi tube. The problem of measurement of the flow rates of two-phase cryogenic flows is urgent for accelerators, as well as for the aerospace and gas-transportation equipment.
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A Method for the Evaluation of the Flow Rate of Cryogenic Two-Phase Flows in Venturi Flowmeters Without Separation
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10.1007/s11018-020-01822-z
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2020-10-01
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The influence of modern additive manufacturing methods, especially from the direct energy deposition (DED) processes to the coat-like finished components, is crucial under present industrial circumstances. DED induces several traits like enhanced mechanical, thermal properties in shorter lead time, which extend their adaptation for diverse applications including aerospace and automobile industries. Among the several DED processes, laser cladding has been a prospect that explores various capabilities of improving the wear resistance of cobalt-chromium (Co-Cr)-based alloys. Rather than fabricating the complete component using expensive alloys, laser cladding has paved an approach to deposit particles possessing superior qualities over the conventional material. This research work attempts to evaluate the surface integrity of SS420 when cladded with Stellite 6. The vertical face milling is executed on the cladded component surface to facilitate either low-plasticity burnishing (LPB) or cryogenic burnishing (CB) as sequential post-treatment processes. The effects of these post-treatments on the surface and subsurface microhardness, surface topography and residual stress profiles are elaborated. Increased surface and subsurface microhardness, as well as improved residual stress profiles, are observed with CB over LPB-processed specimen samples.
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Effect of Cryogenics-Assisted Low-Plasticity Burnishing on Laser-Clad Stellite 6 over SS420 Substrate
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10.1007/s11665-020-05152-7
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2020-10-01
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The cryogenic process has been widely applied in various fields, but it has rarely been reported in the preparation of anode materials for lithium-ion battery. In this paper, activated carbon derived from hemp stems was prepared by carbonization and activation; then, it was subjected to cryogenic treatment to obtain cryogenic activated carbon. The characterization results show that the cryogenic activated carbon (CAC) has a richer pore structure than the activated carbon (AC) without cryogenic treatment, and its specific surface area is 1727.96 m^2/g. The porous carbon had an excellent reversible capacity of 756.8 mAh/g after 100 cycles at 0.2 C as anode of lithium-ion battery, in which the electrochemical performance of CAC was remarkably improved due to its good pore structure. This provides a new idea for the preparation of anode materials for high-capacity lithium-ion batteries.
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Effect of Deep Cryogenic Activated Treatment on Hemp Stem-Derived Carbon Used as Anode for Lithium-Ion Batteries
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10.1186/s11671-020-03422-w
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2020-10-01
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In February this year the Chair of Mineral Processing was given the chance to extend its laboratories into the 3rd floor of the Impulszentrum Raw Materials based on chair-internal research work on fine particle grinding comminution and in cooperation with the “Materials Center Leoben Forschung GmbH”. The additional area comprises 175 m^2. Generous financial support of the Montanuniversitaet Leoben granted in two university internal infrastructure funding programmes on application of the Chair of Mineral Processing allowed to raise the equipment necessary to realize research objectives in energy-optimized fine particle grinding (–5 µm), smart processing and integral processing by using the mill additionally as a chemical reactor. Apart of the cryo-grinding lab, the construction work for the new flotation laboratory and an analytical lab will be finished by the end of the year. A mobile stirred mill at pilot scale and a lab mill for cryogenic comminution as well as grinding at raised gas pressure are the test rigs which are integrated in various research projects to verify the industrial applicability of process ideas. Fine grinding, mill sizing, automation of grinding processes and process development beyond the common use of stirred mills are made accessible to the Chair of Mineral Processing by these technical improvements. Im Februar dieses Jahres konnte der Lehrstuhl für Aufbereitung und Veredlung auf Basis von lehrstuhlinternen Forschungsarbeiten zur Zerkleinerungstechnik in Kooperation mit dem „Materials Center Leoben Forschung GmbH“ (MCL) die Laboratorien in den 3. Stock des Impulszentrums für Rohstoffe und damit um eine Gesamtfläche von ca. 175 m^2 ausdehnen. Mit finanzkräftiger Unterstützung durch die Montanuniversität Leoben, die zwei Anträge der Lehrstuhlleitung (hausinterne Impulsprogramme) positiv bewertete, konnte die apparative Ausrüstung aufgebaut werden, um die Forschungsziele Energieoptimierte Feinstzerkleinerung <5 µm, Smart processing und Integrale Prozessführung „mill as reactor“ in Angriff zu nehmen. Daneben werden ein zusätzliches Flotationslabor und Räumlichkeiten für Analytik mit Ende des Jahres einsatzbereit sein. Eine mobile Pilotanlage zur Rührwerkskugelmühlenmahlung und eine Labormühle für kryogene Mahlung sowie Mahlung bei erhöhtem Gasdruck sind die Anlagen, die in unterschiedlichen Forschungsprojekten erprobt, genutzt und zur Prozessreife geführt werden sollen. Die technische Erweiterung erschließt dem Lehrstuhl die Feinstzerkleinerung, Anlagenauslegung, Automatisierung von Zerkleinerungsabläufen und Prozessentwicklung jenseits des herkömmlichen Einsatzes von Mühlen in der Primär- und Sekundärrohstoffaufbereitung.
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The 3rd Level – Entwicklung der Feinstzerkleinerung und Ausbau der Flotation am Lehrstuhl für Aufbereitung und Veredlung
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10.1007/s00501-020-01058-y
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2020-09-23
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Densities of two methane-rich binary mixtures were measured in the homogeneous liquid and the supercritical region at temperatures between (100 and 160) K using a low-temperature single-sinker magnetic-suspension densimeter. For each mixture, four isotherms were studied over the pressure range from (0.3 to 10.8) MPa. Molar compositions of the gravimetrically prepared methane-rich binary mixtures were approximately 0.01 butane and 0.02 isopentane, respectively, with the balance being methane. The relative expanded combined uncertainty ( k = 2) of the experimental densities was estimated to be in the range of (0.02 to 0.06) %. Due to a supercritical liquefaction procedure and the integration of a special VLE-cell, it was possible to measure densities in the homogeneous liquid phase without changing the composition of the liquefied mixture. Based on the supercritical liquefaction procedure, a new time-saving measurement procedure was developed and applied. Moreover, saturated-liquid densities were determined by extrapolation of the experimental single-phase liquid densities to the vapor pressure calculated with an equation of state (EOS); here, the relative expanded combined uncertainty ( k = 2) is less than 0.05 % in most cases. The new experimental results were compared with the GERG-2008 equation of state, the EOS-LNG and the enhanced revised Klosek and McKinley (ERKM) method.
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Density Measurements of (0.99 Methane + 0.01 Butane) and (0.98 Methane + 0.02 Isopentane) over the Temperature Range from (100 to 160) K at Pressures up to 10.8 MPa
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10.1007/s10765-020-02728-2
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2020-09-18
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The super alloy exhibits great strength and fatigue behaviour when nickel (Ni) is present in major quantities. Moreover, it possesses good corrosive resistant behaviour at high temperatures. However, these alloys are very difficult to machine under normal machining conditions due to their great strength and low heat dissolution. In this work, machining was performed on Hastelloy C276 under various machining conditions (speed, feed and depth) and environments (dry and cryogenic). Liquid nitrogen was used as a coolant in the machining region. The machinability of Hastelloy C276 was investigated with machining forces, temperature, surface roughness and hardness under different cutting conditions. Turning experiments that resulted from passing LN_2 drastically reduced temperature by up to 40%. Machining forces were minimal under cryogenic machining due to its effective lubrication property. Surface finish of the machined area improved by about 26% under cryogenic conditions. Both dry and cryogenic machining improved the hardness of the work material. The high cooling efficiency of LN_2 improved hardness of the machined surface was about 8-15%. Chip width and side-flow of chip material were reduced under cryogenic cooling. Moreover, adhesion and abrasion wear were observed minimally in cryogenic machining compared to dry machining. But no significant difference was observed in notch wear for both types of machining. Machinability of Hastelloy C276 significantly improved when LN_2 used as a cutting fluid.
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Experimental investigations on cryo-machining of Hastelloy C-276 with tool wear characteristics
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10.1007/s12046-020-01477-0
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2020-09-17
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Abstract Undersized crawfish have little economic value and are often discarded. Producing crawfish minced meat (CMM) from undersized crawfish and using an appropriate freezing technique may enable an economically viable market. The objective of this research was to evaluate the effect of the energy removal rate using two techniques, cryogenic freezing (CF) and air blast freezing (BF), on CMM’s quality during frozen storage. CMM was separated into two batches; one batch was cryogenically frozen with liquid nitrogen and the other batch was frozen with an air blast freezer. CMM batches were frozen and stored at − 18 °C. They were analyzed for moisture content, color, pH, and lipid oxidation during 180 days of storage. The CMM yield was 64.67% of the total crawfish weight. Cryogenic freezing achieved the highest freezing rate. Cryogenically frozen CMM showed 22% less lipid oxidation than CMM frozen by air blast freezing at 180 days of storage. This study showed that CMM could be mechanically produced from undersized crawfish and freezing techniques with high energy removal rate could better maintain quality attributes for CMM during frozen storage. Graphical abstract
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Influence of energy removal rate on the quality of minced meat from undersized crawfish during frozen storage
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10.1186/s43014-020-00033-x
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2020-09-14
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Background Numerous sensing techniques have been investigated in an effort to monitor the main parameters influencing the residual limb/prosthesis interface, fundamental to the optimum design of prosthetic socket solutions. Sensing integration within sockets is notoriously complex and can cause user discomfort. A personalised prosthetic liner with embedded sensors could offer a solution. However, to allow for a functional and comfortable instrumented liner, highly customised designs are needed. The aim of this paper is to presents a novel approach to manufacture fully personalised liners using scanned three-dimensional image data of the patient’s residual limb, combined with designs that allow for sensor integration. To demonstrate the feasibility of the proposed approach, a personalised liner with embedded temperature and humidity sensors was realised and tested on a transtibial amputee, presented here as a case study. Methods The residual limb of a below knee amputee was first scanned and a three-dimensional digital image created. The output was used to produce a personalised prosthesis. The liner was manufactured using a cryogenic Computer Numeric Control (CNC) machining approach. This method enables fast, direct and precise manufacture of soft elastomer products. Twelve Hygrochron Data Loggers, able to measure both temperature and humidity, were embedded in specific liner locations, ensuring direct sensor-skin contact. The sensor locations were machined directly into the liner, during the manufacturing process. The sensors outputs were assessed on the below amputee who took part in the study, during resting (50 min) and walking activities (30 min). To better describe the relative thermal properties of new liner, the same tests were repeated with the amputee wearing his existing liner. Quantitative comparisons of the thermal properties of the new liner solution with that currently used in clinical practice are, therefore, reported. Results The liner machining process took approximately 4 h. Fifteen minutes after donning the prosthesis, the skin temperature reached a plateau. Physical activity rapidly increased residuum skin temperatures, while cessation of activity caused a moderate decrease. Humidity increased throughout the observation period. In addition, the new liner showed better thermal properties with respect to the current liner solution (4% reduction in skin temperature). Conclusions This work describes a personalised liner solution, with embedded temperature and humidity sensors, developed through an innovative approach. This new method allows for a range of sensors to be smoothly embedded into a liner, which is capable of measuring changes in intra-socket microclimate conditions, resulting in the design of advanced socket solutions personalised specifically for individual requirements. In future, this method will not only provide a personalised liner but will also enable dynamic assessment of how a residual limb behaves within the socket during daily activities.
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A personalised prosthetic liner with embedded sensor technology: a case study
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10.1186/s12938-020-00814-y
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2020-09-14
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This research work was carried out to find a suitably treated electrode for the required machining output response like MRR and TWR. The experimental design was formed using Box–Behnken design. Experiments were conducted to machine 500 µm holes on titanium (Ti-6Al-4V) alloy using copper electrodes. Input parameters selected were input current ( I _p), pulse-on time ( T _on), and pulse-off time ( T _off). Material removal rate and tool wear rate were analyzed using contour plots. Based on these experimental data, the grey relational analysis technique was applied to find the optimal parameters for achieving maximum MRR and minimum TWR. Optimal parametric values obtained were input current ( I _p) 4.0 A, pulse on time ( T _on) 2.0 µs and pulse off time ( T _off) 6.4 µs. The achieved optimized parameters were further used to conduct experiments with cryogenic treated and coated electrodes. Electrodes were coated with conductive materials (silver, nickel, and zinc) and non-conductive material (epoxy). The experimental results showed each type of electrode enhances a particular machining characteristic such as silver-coated electrode produced a higher value of MRR, epoxy-coated electrode achieved minimum TWR. It is observed from the results that this work can be applied to identify the suitable electrode for producing the desired machining output characteristics.
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Effect of coated and treated electrodes on Micro-EDM characteristics of Ti-6Al-4V
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10.1007/s40430-020-02578-x
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2020-09-07
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Background The essential oil is one of the main active ingredients of Amomum villosum Lour. However, volatile compounds are easily lost during the drying, storage and even sample preparation procedure. Therefore, using fresh samples can obtain more accurately data for qualitative and comparative analysis. Methods In this study, the volatile compounds in different parts of fresh A. villosum from different origins were systemic analyzed and compared by using cryogenic grinding combined HS–SPME–GC–MS for the first time. GC–MS analyses were performed on a 6890 Series GC instrument coupled to a 5973 N mass spectrometer. The volatile compounds were extracted by the SPME fiber (100 μm PDMS). Analytes separation was achieved on a HP-5MS capillary column. The oven temperature was initially programmed at 70 °C, then raised 4 °C/min to reach 125 °C and then programmed at 0.5 °C/min to 133 °C, then at 6 °C/min to 170 °C and finally, at 20 °C/min to 280 °C held for 2 min. The temperatures of the injection port, ion source and transfer line were set at 250 °C, 230 °C and 280 °C, respectively. Results Forty-eight main compounds were identified in different parts of fresh A. villosum . The most abundant components in fresh fruit samples were camphor (3.91%), bornyl acetate (10.53%), caryophyllene (8.70%), β-bisabolene (11.50%), (E)-nerolidol (14.82%) and cubenol (10.04%). This is quite different with that of dried samples analyzed in our previous work. As different parts of the same plant, many common components with biological activities were detected in fruit and other parts. In principle components analysis (PCA) and hierarchical clustering analysis (HCA), four parts of A. villosum were divided into different groups clearly. Additionally, fruit and root samples also could be divided into two subgroups (HCA) in accordance with their regions. Conclusion The developed method was successfully used for qualitative and comparative analysis of volatile compounds in fresh A. villosum samples. Additionally, using fresh samples can obtain much more information which is helpful for their performance in the fields of functional foods, agriculture and biomedical industry. Furthermore, our research is helpful for comprehensive utilization and quality control of A. villosum .
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Comparison of volatile compounds in different parts of fresh Amomum villosum Lour. from different geographical areas using cryogenic grinding combined HS–SPME–GC–MS
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10.1186/s13020-020-00377-z
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2020-09-01
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The titanium alloy has a low thermal conductivity of 1/8th that of common metals and half that of stainless steel. The heat dissipation is poor during dry cutting, so the cutting temperature rises above about 600°C. Due to this, the quality of the cutting surface decreases during machining, and rapid tool wear occurs. To solve this, the use of cutting fluid is essential, but the chemical composition of the cutting fluid has a negative effect on the body and the environment. In the current cutting process, in order to minimize this effect, eco-friendly processing using minimum quantity lubrication (MQL) is performed. The machining method using both MQL and a cryogenic gas separately applies the MQL and the cryogenic gas to both sides of the cutting tool. In this case, the oil mist cannot penetrate the cutting zone due to the spray pressure of the cryogenic gas. Therefore, it is necessary to design a hybrid nozzle that can spray oil mist and cryogenic gas into a single flow. Besides, although the study on the effect of MQL and cryogenic machining on the cutting temperature should be preceded, most of the titanium MQL processing papers only study the material surface and tool wear. Accordingly, in this study, we designed and fabricated the hybrid type nozzle of CryoMQL which combined MQL and a cryogenic gas to improve the spraying concentration. And the cutting temperature generated by the process was measured, and the effectiveness of the proposed nozzle on decreasing the cutting temperature was evaluated. Besides, cutting force and tool wear were analyzed according to each cutting method.
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Investigation on influence of hybrid nozzle of CryoMQL on tool wear, cutting force, and cutting temperature in milling of titanium alloys
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10.1007/s00170-020-05646-7
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2020-09-01
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Searches for dark matter with cryogenic detectors are pushing to lower energy thresholds at each development stage. Consequently, new approaches for detector calibration at the proposed energy scales are necessary. In the case of SuperCDMS SNOLAB, energy thresholds in the range of a few eV are expected. In this paper, we are reporting R&D work for new ideas to calibrate cryogenic detectors in the eV range utilizing LEDs of various wavelengths operated at cryogenic temperatures.
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New Approaches to Low-Energy Calibration of Cryogenic Detectors
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10.1007/s10909-020-02469-4
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2020-09-01
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Extended X-ray absorption fine structure (EXAFS) spectroscopy is a powerful technique that gives element-specific information about the structure of molecules. The development of a laboratory EXAFS spectrometer capable of measuring transmission spectra would be a significant advance as the technique is currently only available at synchrotron radiation lightsources. Here, we explore the potential of cryogenic detectors as the energy-resolving component of a laboratory transmission EXAFS instrument. We examine the energy resolution, count rate, and detector stability needed for good EXAFS spectra and compare these to the properties of cryogenic detectors and conventional X-ray optics. We find that superconducting tunnel junction detectors are well-suited for this application.
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Feasibility of Laboratory-Based EXAFS Spectroscopy with Cryogenic Detectors
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10.1007/s10909-020-02474-7
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2020-09-01
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Steel AISI O2 (type 9G2) for a cold-working tool after different quenching, tempering, and cryogenic treatment regimes is studied. It is established that after cryogenic treatment the amount of residual austenite decreases by a factor of 4.3 compared with a quenched condition. The highest hardness 69 HRC is achieved after quenching and cryogenic treatment, and in this case wear resistance is higher by a factor of 2.36 than after quenching and tempering. After cryogenic treatment there is also a reduction in friction coefficient.
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Microstructure and Tribological Properties of Tool Steel AISI O2 After Thorough Cryogenic Heat Treatment
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10.1007/s11041-020-00574-5
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2020-09-01
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Quartz fiber–reinforced polyimide composites (QFRP) had heterogeneous and anisotropic properties. Because of the gradient change of cutting force at hole exit, some fibers could not be effectively chipping breaking and the defect of delamination burr was often inevitable. In this paper, a cutting force model of fiber fracture stripping considering thermal–mechanical coupling was constructed based on the mechanism of cutting force and thermal action. A series of milling hole tests at different temperatures (from 290 to 80 K) was carried out using liquid nitrogen inner-cooling equipment. Similarly, the hole exit morphology, milling force, and cutting temperature were investigated and the delamination factors were calculated in detail. The results show that the model can explain the reason of hole exit defect, which is attributed to the lack of tangential cutting force and the large gradient change of axial force considering the high cutting temperature. Meanwhile, cryogenic cooling can reduce the effect of cutting temperature for hole exit defect. Although the cutting force is increased, the gradient degree of axial force can be reduced, and the delamination factor can be decreased from 1.08 at low-speed dry cutting to 1.01 of high-speed cryogenic one. At the same time, the increase of tangential force and the decrease of fiber ductility improve the chip breaking ability and the processing efficiency. Conclusion: the spiral hole milling process with cryogenic medium intervention can inhibit the milling hole delamination defects.
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Influence of cryogenic cooling on milling hole exit of QFRP based on thermal–mechanical coupling
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10.1007/s00170-020-05916-4
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2020-09-01
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In this study, the AZ91 magnesium alloy was subjected to solution and ageing heat treatment (T6) and deep cryogenic (DC) treatment to enhance the wear performance. For this purpose, the solution treatment process was performed at 400 °C for 4 h, 5 h, and 6 h, followed by ageing at 200 °C for 10 h to complete T6 treatment. Then, the DC treatment was carried out at − 196 °C for 48 h. The pin-on-disc method was employed to measure the wear resistance of the samples. The results show that the solution treatment period altered the microstructure of AZ91; the eutectic phase was more dissolved in the matrix after 4 h of solution treatment time. Regarding the DC-treated AZ91, new double twins frame-like β phases were observed on the surface. Moreover, cryogenic treatment improved the hardness from 63 to 75 HV, but the wear rate was slightly higher than untreated AZ91 in dry medium. On the other hand, lower wear rate was obtained when applying 4 h of solution treatment time with DC treatment. In contrast, 6 h of solution treatment time with DC treatment exhibited higher wear rate, probably due to greater amounts of double twins.
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The Impact of Solution Treatment Time (T6) and Deep Cryogenic Treatment on the Microstructure and Wear Performance of Magnesium Alloy AZ91
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10.1007/s11665-020-05058-4
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2020-09-01
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Abstract Results characterizing the Pleistocene environments in the region of Northwestern Siberia are presented. The study of these environments is carried out from the perspective of the scientific concept of cryoheterotopy; this scientific approach is based on analysis of the typicality, atypicality, and utopicity of the positions of objects in space, which is united by a cryogenic system. A case study of the application of the developed approach to analyze the causes of contradictions regarding the structure of the regional Quaternary rock complex and crustal dynamics in the region in the Pleistocene is discussed, and a way to resolve these contradictions is presented. The characteristic features of development of the region studied are considered from the cryoheterotopic point of view.
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Analysis of Pleistocene Cryogenic and Tectonic Processes in Northwestern Siberia: A Cryoheterotopic Approach
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10.1134/S1028334X20090160
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2020-09-01
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The CALDER project aims to realize cryogenic light detectors for the next generation of experiments searching for rare events. More in detail, the main application of these devices will be the background suppression in future cryogenic calorimetric experiments searching for neutrinoless double beta decay ( $$0\nu $$ 0 ν DBD). This is the case of CUPID, a next-generation $$0\nu $$ 0 ν DBD observatory, able to take advantage from particle identification to dramatically reduce the background events. In this contribution, we show the status of the CALDER project. The light sensors developed in this R&D are based on kinetic inductance detector operated in the phonon-mediated approach. Their energy resolution (20 eV), time response ( $$\upmu $$ μ s) and multiplexing capability make them very promising for the future CUPID experiment.
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Cryogenic Light Detectors for Background Suppression: The CALDER Project
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10.1007/s10909-020-02496-1
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2020-09-01
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Abstract A possibility of contactless switching of an NbN nanowire from superconducting to normal state by passing a current through a gate located at a certain distance from the nanowire is demonstrated. The gate, being isolated from the nanowire by an Al_2O_3 layer, contains an integrated resistance formed by ion irradiation. Dependences of the minimum power released in the gate that is sufficient for nanowire to pass to the normal state on the dc current through the nanowire are experimentally obtained. A signal inverter containing three successive cascades is developed based on this principle. This design shows that the proposed approach can be used to form a logic element base for cryogenic computing.
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Control of Superconducting Transitions in Nanowires Using Galvanically Uncoupled Gates for Designing Superconductor-Based Electronic Devices
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10.1134/S1063783420090103
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2020-08-01
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Many buses use cryogenic container to store the LNG as fuel. The heat insulated performance is an important parameter that reflected with daily evaporation rate or heat leakage of cryogenic container. In bus running process, the LNG container is affected by many factors and difficult to assess and analyze the heat insulated performance. In order to solve this problem, firstly, according to the LNG container heat leakage transfer process in bus running, the energy equations of the LNG were established. Secondly, the factors were analyzed that affected the heat insulated of the LNG cryogenic container. Then, the heat leakage was calculated depending on the test data of the LNG container in the bus running to estimate the heat insulated performance. At the same time, the LNG container heat insulated performance was also measured at the local inspection agency. We found that there were great differences between the two results, and the reasons for the great differences were further analyzed.
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Bus LNG container heat insulated performance estimate
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10.1007/s12206-020-0730-2
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2020-08-01
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An efficient long-term storage of cryogenic propellants is a challenge for future space exploration missions. The vapour bubbles formed as a result of boil-off in the tank walls can generate foam structures, which could be hazardous in different operations in orbit. A recently proposed approach to control the dynamics of bubbles is based on the generation of an acoustic field by means of a piezoelectric transducer. This technology needs to be validated at cryogenic temperatures in order to be applicable in space. In this perspective, different piezoelectric elements and matching layer materials have been tested at cryogenic temperatures to assess their performance at such environmental conditions. We consider the use of soft PZT piezoceramics coupled with an epoxy resin as the matching layer. Experimental data reveal that epoxy resin-based acoustic matching layers exhibit a linear increase in the transmittance of the acoustic amplitude at cryogenic conditions. The peak-to-peak amplitude increases as temperature decreases up to a factor of 1.6. This result opens the possibility of generating and transmitting acoustic waves at cryogenic temperatures, which could be used in the recently proposed technology to control the dynamics of vapour bubbles in cryogenic fuel tanks.
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Performance Assessment of Ultrasonic Waves for Bubble Control in Cryogenic Fuel Tanks
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10.1007/s12217-020-09795-y
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2020-07-01
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Abstract Presented are the results of experimental studies into the interaction between the surface and subsurface water in 16 mountain river basins of East Sayan and Lake Baikal as carried out by the Irkutskbased Institute of Geography during 1984‒1990. The research program included regular measurements of the thickness, area and volume of the surface and underground ice along the entire length of the valleys, pressure in closed lenses of underground waters, daily measurements of water discharges and chemical composition throughout the channel network. It was found that at the end of winter about 80‒90% of the area of the valleys of the rivers under study are covered by aufeis and by the seasonal subsurface ice of a different genesis. Furthermore, about half the volume of the seasonal ice corresponds to the surface ice (river ice and aufeis), and the other half to the subsurface segregated and injection ice. It was further shown that the period of formation of the main bulk of ice begins and ends earlier in the sections closer to the mouth. The “wave” of maximum intensity of ice formation gradually moves the river upstream. The ice volume is the last to form in the upstream components of the river network. At this time, the ice formation of the other area of the watershed has terminated or its main part has formed already. A cryogenic barrage phenomenon occurs, as a result of which the channel network receives subsurface water which, under normal conditions, is not drained by the river. The winter river runoff increases from 50% in the sections close to the source to 5‒10% at the mouth of the river.
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Water Exchange in Small Riversheds With Severe Climatic
Conditions During a Cold Period of a Year
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10.1134/S1875372841030105
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2020-07-01
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Excellent cryogenic mechanical properties are urgently requested for the materials used in liquid oxygen environment. However, a DOPO-modified epoxy resin (EP-P), which was compatible with liquid oxygen, had no improved cryogenic mechanical properties compared with the pure epoxy resin (EP). Besides, its mechanical properties at room temperature (RT) were obviously decreased compared with EP. Thus, a novel epoxy-grafted polysiloxane (EGP) was synthesized by dimethyldimethoxysilane, dimethoxydiphenylsilane and 3-glycidoxy-propyltrimethoxysilane through co-hydrolytic condensation reaction. EGP was introduced into EP-P to improve cryogenic mechanical properties, especially toughness of EP-P. Tensile properties and fracture toughness of the DOPO/EGP-modified epoxy resin (EP-P/Si) at RT and liquid oxygen temperature (90 K) were investigated. Compared with EP, at RT, failure strain and K _IC of EP-P/Si were increased by about 100% and 40%; at 90 K, the above two properties were increased by about 60% and 50%. Besides, EP-P/Si had almost same tensile strength with EP at both RT and 90 K. The results of the liquid oxygen mechanical impact test indicated that EP-P/Si was still compatible with liquid oxygen. XPS analysis showed that EP-P/Si had lower oxidation degree after the impact test compared with EP-P, indicating that liquid oxygen compatibility was enhanced.
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Enhanced cryogenic mechanical properties and liquid oxygen compatibility of DOPO-containing epoxy resin reinforced by epoxy-grafted polysiloxane
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10.1007/s00289-019-02931-8
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2020-07-01
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Abstract— Pedogenesis on the terraces of lacustrine–alas depressions in the tundra zone of the Kolyma Lowland takes place on sediments that are different in genesis but have significantly similar composition and properties. Soil morphology and soil cover patterns on terraces and slopes of depressions reflect the main trends of the Holocene pedogenesis and the rearrangement of the environment. On the terraces of the upper and middle levels, as well as on the interfluves, the major pedogenic trend is cryozem formation. On the lower terraces and in the bottoms of lacustrine–alas depressions, gleyzation and peat formation are considered to be stable and progressing processes. Soil formation is affected by close permafrost table (<1 m); therefore, all soils are qualified for Cryosols.
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Soils and Sediments of the Lacustrine-Alas Depressions in Tundra Zone of the Kolyma Lowland
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10.1134/S1064229320070042
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2020-07-01
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Abstract The results of long-term studies of a group of aufeis-forming Buluus groundwater sources are given. A stow, which has been formed by the spring, contains the drainage area of the suprapermafrost–intrapermafrost aquifer, which is widespread in the sand deposits of the bestyakhskaya terrace of the Lena River in Central Yakutia. The analysis of observations of 1964–2017 showed stable water chemistry in Buluus spring at the long-term scale. Considerable seasonal variations of water chemistry are typical of low-discharge springs, which start functioning after becoming free of aufeis. The spring water also shows higher concentrations of lithium and fluorine. The possible causes of the different chemistry of spring water are discussed, with special attention paid to the local activity of rock freezing and thawing processes in the aufeis valley. It is shown that groundwater samples are to be taken from all springs in the areas of their group discharge with the aim to assess the effect of natural and technogenic factors on the permafrost–hydrogeochemical conditions.
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Groundwater Hydrochemistry of Suprapermafrost–Intrapermafrost Flow in Their Discharge Areas in Central Yakutia
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10.1134/S0097807820040119
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2020-07-01
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Recent trends in metal cutting shows the increasing of demand at the global stage for the application of eco-friendly machining approaches in order to eliminate the adverse effects of conventional cutting fluids. Thus, this experimental work was conducted to evaluate the performance of sustainable cooling techniques of cryogenic carbon dioxide (CO_2), Minimum Quantity Lubrication (MQL), cryogenic liquid nitrogen (LN_2) and dry cutting on machinability of Inconel 718. For the cryogenic CO_2 approach, a new concept of cryogenic cooling technique was introduced for efficient and consistent cooling performance. The findings displayed cryogenic CO_2 as a promising coolant since it resulted in slower tool wear rate compared to cryogenic LN_2 and dry cutting, while being more effective in decreasing cutting forces and surface roughness compared to other approaches. Its adequate and consistent cooling efficiently disperses the generated heat and creates an ideal cutting condition for the tool and workpiece to interact with each another during cutting. In contrast to MQL cutting, the usefulness of CO_2 was supplanted due to the resulting shorter tool life. As such, the MQL approach is preferred as it extends the tool life longer by 67.2% with the maximum volume of material removal as compared to cryogenic CO_2. Its lubrication impact shows effectiveness in diminishing the tool wear rate than the cooling effect by the cryogenic CO_2. However, from the viewpoint of sustainability, MQL could be less preferable due to unpleasant odour and settling of MQL mist around the cutting area.
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Sustainable Machining of Hardened Inconel 718: A Comparative Study
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10.1007/s12541-020-00332-w
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2020-07-01
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Abstract This work reports on the laboratory study of gas filtration in ice samples with various salinities and frozen soils. For this purpose, the frozen soils were affected by pressurized gas in a specially designed apparatus. Then, the structure of the samples was studied with the use of the texture and structure observations in transmitted, reflected, and polarized light. During the experiments, it was possible to identify the processes that accompany gas filtration in ice with various salinities and frozen soils, and to establish the temperatures at which gas filtration begins.
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Gas Filtration in Frozen Soils
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10.3103/S0145875220040109
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2020-07-01
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The machinability of composites had close relationship with cutting force. A milling hole force model of quartz fiber-reinforced polyimide composites (QFRP) was constructed considering cutting microzone temperature. A series of cryogenic milling hole testes were carried out through a liquid nitrogen inner cooling cutting equipment. The surface morphology and cutting force performance at hole entry and exit were analyzed in detail. The results show that helical milling force is mainly related to the axial feed, tangential feed, and mechanical properties of composites in different temperatures and changed slowly with spindle speed. The influence of axial feed on force is larger than that of tangential one. Meanwhile the large cutting force at hole entry and the little force at hole exit have the main reasons of the crimping and delamination defects. After cryogenic is intervened, the milling force is significantly improved, and the defects are effectively restrained. Especially, the hole entry and exit accuracies can be reached 0.03 mm, and there are no low-speed tearing and high-speed ablation defects. Furthermore, the change of force is caused by the change of properties of matrix, and composite at low temperature is the main reason to restrain defects. The cooling medium can avoid the phenomenon of increasing cutting force caused by tool expansion, as well as restraining the ablative defect.
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Milling hole force of Quartz fiber-reinforced polyimide composite in cryogenic cooling
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10.1007/s00170-020-05659-2
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2020-07-01
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Tough-pitch copper M1 is studied after deformation by the method of equal channel angular pressing (ECAP) in a die with parallel channels with the use of cryogenic cooling in liquid nitrogen. Comparative analysis of the properties of the copper after the ECAP with cooling in liquid nitrogen and at room temperature is performed. Special features of formation of ultrafine-grained structure in quenched copper M1 under the ECAP in the die with parallel channels are determined. The role of cooling with liquid nitrogen after the ECAP is shown to be positive from the standpoint of deceleration of the processes of static and dynamic recrystallization and improvement of the combination of the mechanical properties of the copper.
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Evolution of the Microstructure and Mechanical Properties of Copper under ECAP with Intense Cooling
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10.1007/s11041-020-00544-x
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2020-06-01
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Purpose The accelerator-driven subcritical system (ADS) is the internationally recognized key technology of nuclear waste problem treatment, of which superconducting proton linac is an important part. With the support of the strategic science and technology pilot project of the Chinese Academy of Sciences, the Institute of High Energy Physics of the Chinese Academy of Sciences took the lead in the research of 325 MHz superconducting proton linac, which is called ADS Injector I. The superconducting accelerator part of ADS Injector I mainly consists of 14 spoke-type superconducting cavities with β 0.12. At the same time, the research work of various cavities with different β values and different frequencies is also carried out to lay the technical and technological foundation for ADS main accelerator. The only way to determine whether the superconducting cavity can reach the design target and whether it can be installed into the cryostat is the vertical test at cryogenic. As the only way to test the microwave performance of the superconducting cavity at low temperature, the vertical test can accurately test the acceleration gradient Eacc and the corresponding quality factor Q _ 0 of the superconducting cavity. The design and construction of the superconducting cavity vertical test facility is based on the practical needs of the pilot project and the long-term development of the superconducting accelerator. Methods This paper mainly introduces the design and construction of the cryogenic vertical test system for the superconducting cavity of ADS Injector I, including the system scheme design, process design, heat load analysis, 2 K superfluid helium obtaining method, system commissioning and operation, etc. Results and Conclusion The static heat leakage at 2 K of the 2 K superfluid helium vertical test system of ADS Injector I is 1.624 W, which has reached the international advanced level. The 2 K superfluid helium vertical test system of ADS Injector I after constructed not only meets the test requirements of ADS pilot project, but also conducts 4 K and 2 K vertical tests for other different types of superconducting cavities and relevant cryogenic experiments.
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2 K superfluid helium cryogenic vertical test system for superconducting cavity of ADS Injector I
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10.1007/s41605-020-00167-z
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2020-06-01
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This paper focuses on the impact of cryogenic assistance on the drilling of Ti6Al4V titanium alloy. It develops a relation between the phenomenon of hole shrinkage and measurements performed either during or after the machining operation. Indeed, because this phenomenon is apparently strongly associated with heat generation, which is the main issue in titanium alloy drilling, this work proposes to verify the effect of liquid nitrogen cooling on hole shrinkage, quantify it, and then relate it to these measurements. Specifically, the cutting forces and final hole geometry are analyzed and their variations are explained using the collected data on hole shrinkage.
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Effect of cryogenic assistance on hole shrinkage during Ti6Al4V drilling
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10.1007/s00170-020-05381-z
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2020-06-01
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The primary role of hard turning is to realize surfaces with high dimensional accuracy and high surface integrity to improve functional performances of the manufactured product. To this aim, the turning process parameters have to be carefully chosen. The present work deals with the correlation between hard turning parameters, surface and sub-surface characteristics, and corrosion behavior of the AISI 52100 bearing steel. Different cutting speeds and cooling conditions, specifically conventional flood and cryogenic cooling, were used for hard turning. Microstructural observations, residual stresses, nano-hardness, and surface finish measurements were carried out to assess the surface integrity modifications induced by machining. Then, potentiodynamic polarization curves were carried out, and the corroded surfaces were inspected. The obtained results showed that a remarkably improved corrosion resistance was obtained by using the lowest adopted cutting speed coupled with cryogenic cooling. Specifically, the former contributed to generate a wider nanostructure layer close to the machined surface, while the latter induced compressive residual stress state in correspondence of it.
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Surface integrity and corrosion performances of hardened bearing steel after hard turning
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10.1007/s00170-020-05352-4
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2020-06-01
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In planned planetary explorations, cryogenic liquids such as liquid hydrogen (LH_2), liquid oxygen (LOX), and liquefied natural gases (LNG) are used as fuel and oxidants in the propulsion systems of spacecraft. Such explorations require long-term storage for those cryogens, as well as heat insulation technology to protect the heat from the outside and pressure control technology to suppress rises in pressure due to evaporation gas in the propellant tank. However, current vent systems that discharge the evaporated gas to the outside of the spacecraft are suboptimal, for the propellant’s uncertain position in the tank when spacecraft operate in microgravity environments causes the significant loss of propellant during venting. In response, we examined a method using jet mixing in a thermodynamic vent system (TVS) that adjusts the tank pressure by cooling the inside of the tank and reducing boil-off gas. To that end, thermal and fluid analyses were conducted to design a test tank system before the ground verification test of the TVS using liquid nitrogen (LN_2) as the simulated cryogen. To evaluate our results, we compared experimental and numerical results regarding the formation of thermal stratification. The experimentally performed verification of the TVS function revealed that jet mixing can lower the liquid’s temperature in the tank after the experimental apparatus was modified to supply a stable subcooled mixing jet.
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Basic Study on Thermodynamic Vent System in Propulsion System for Future Spacecraft
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10.1007/s12217-019-09768-w
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2020-06-01
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The effects of nitrogen content and hot forming temperature on prior austenite grain size for normalizing cryogenic pressure-vessel steels were described. The evolution of V(C,N) precipitates during thermal cycle of hot forming was analyzed. The optical microscopy displays that as increasing N content from 0.0094 to 0.0198 wt.% the refinement of prior austenite grain was seen at each hot forming temperature of 870, 910 and 950 °C. The transmission electron microscopy presents that much finer V(C,N) precipitates were found in sample with 0.0198 wt.% N content than in sample with 0.0094 wt.% N content. Thermo-Calc calculation reveals the precipitation temperature of V(C,N) was increased by increasing N content. While the Ostwald ripening rate of V(C,N) was decreased by increasing N content. TEM result and Thermo-Calc calculation indicate that increasing N content enhanced the thermal stability of V(C,N) precipitates. The stable finer V(C,N) precipitates contribute to the finer prior austenite grain and good mechanical properties for sample with 0.0198 wt.% N content even at higher temperature of 950 °C during hot forming process.
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Effects of Nitrogen Content and Hot Forming Temperature on Prior Austenite Grain Size and Mechanical Properties for Normalizing Cryogenic Pressure-Vessel Steels
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10.1007/s11665-020-04924-5
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2020-06-01
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In order to investigate the wicking performance of cryogenic propellants within metallic screens for space liquid acquisition devices, a modified one-dimensional macroscopic model is introduced. The model is successfully verified by the experimental data of both isothermal and superheated wicking. Dutch twill weave 200 × 1400 in the warp direction is chosen as the screen object. Three cryogenic propellants such as hydrogen, oxygen and methane are selected as the working fluids. The wicking performances at different thermal conditions (isothermal and superheated) and gravity levels (Earth, Mars, Moon and space) are investigated. Results show that the wicking velocity and maximal wicking height both have a negative correlation with the gravity and superheated degree. The wicking performance deviation between different fluids or different superheated conditions increases as the gravity decreases. LH_2 always has the fastest initial wicking velocity, but its wicking performance rapidly deteriorates to the worst at superheated conditions due to its strongest ability of heat transfer. The wicking performance of LO_2 is the worst at isothermal condition, but becomes better than that of LH_2 at superheated condition. Wicking of LCH_4 always has the largest maximum wicking height and performs the best among the three propellants under the same condition.
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Investigation on Wicking Performance of Cryogenic Propellants Within Woven Screens Under Different Thermal and Gravity Conditions
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10.1007/s10909-020-02446-x
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2020-05-14
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This research paper depicts the process of used liquid nitrogen at the interface of TiN coated carbide cutting tool insert (rake face) and AISI D3 workpiece. Design of experiments (DoE) was planned according to Taguchi L_9 (OA) orthogonal array. The experimental results during machining such as cutting force, machining time and temperature were optimized by Taguchi S/N ratio and analysed by ANOVA. The contribution of machining parameters of (i) speed, (ii) feed and (iii) depth of cut for each response were evaluated. Feed had the highest effect on the percentage of contribution of 57.21% and 52.21% for cutting force and machining time, respectively. Speed had the highest effect on the contribution as 79.57% for the temperature at the interface of insert and workpiece. The predicted values at the optimum level of machining parameters for cutting force, machining time and temperature were 44.49 N, 37.09 sec. and 24.99°C, respectively. Regression models were made. The R-Sq values were 96.59, 89.34 and 96.09% for cutting force, machining time and temperature, respectively. The ratio of an average thickness of generated chip and feed was considered as the chip compression ratio. It was observed that the generated chips during cryogenic turning were thin, discontinuous, long snarled and most of the material had side flow on either side.
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Optimization of machining parameters during cryogenic turning of AISI D3 steel
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10.1007/s12046-020-01368-4
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2020-05-09
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The objective of this research is to evaluate the performance of cryogenically treated cemented carbide milling inserts with 11% cobalt content in face milling of EN19 steel. Two different deep cryogenic treatments at temperature of around − 193 °C were performed on the inserts, namely cryogenic treatment and cryogenic treatment and tempering. Uncoated tungsten carbide face milling inserts with 11% cobalt content were used in this research. Machining tests were conducted at the catalog recommended cutting parameters, and flank wear and nose wear of untreated, cryogenically treated and cryogenically treated and tempered inserts were compared to study the performance. The experimental investigation revealed that both cryogenic treated and cryogenic treated and tempered inserts showed 4–7% lesser flank and nose wear than the untreated inserts. The metallurgical examinations using indirect measurement technique revealed the phase transformation of cobalt from FCC to HCP which could have resulted in increased hardness, reduced friction coefficient and improved tool life.
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Investigation on the effect of cryogenic treatment on tungsten carbide milling insert with 11% cobalt (WC–11%Co)
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10.1007/s42452-020-2872-3
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2020-05-01
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Abstract The current results of operation of the first CM1 cryogenic moderator in the direction of neutron beams 7, 8, 10, and 11 at the power of IBR-2 with a new cryogenic system are presented in the paper. A new cryogenic system allowed to reduce the temperature of the working mixture in the chamber of the CM1 moderator when operating at a reactor power of 2 MW by 10 K to ~22–23 K which made possible to acquire gain in the intensity of cold neutrons ~15–20%.
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Gain Factor of the Pelletized Cold Neutron Moderator at 22 K
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10.1134/S1027451020030040
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2020-05-01
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Abstract A measuring complex for recording events by single-photon superconducting detectors based on NbN structures is presented; low-noise high-frequency HEMT transistors are used as cryogenic amplifiers in it.
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A Measuring Stand for Single-Photon Detectors Based on NbN Nanostructures
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10.3103/S0027134920030042
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2020-05-01
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Abstract The review of both previously used lunar deep-hole soil-sampling tools (DSSTs) and new prototypes of these devices, developed for exploring the lunar polar regolith in future lunar projects, is presented, and the DSST options with different technical parameters and layout arrangements intended for future Russian lunar missions are also considered.
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Deep-Hole Soil-Sampling Tools for Future Russian Lunar Polar Missions
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10.1134/S0038094620030089
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2020-05-01
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Despite the multiple and convincing evidence of the existence of dark matter (DM) in our Universe, its detection is one of the most pressing questions in particle physics. As of today, there is no unambiguous hint which could clarify the particle nature of DM. For these reasons, a huge experimental effort is ongoing, trying to realize experiments which can probe the particle properties of DM. In particular, direct search experiments are trying to cover the largest possible mass range, from a few MeVs up to TeVs. Particularly suited for the sub-GeV mass region are detectors containing light nuclei, which are sensitive to the scattering of light DM candidates. Among them, we investigate a carbon-based absorber to explore DM masses down to the MeV region. Thanks to their cryogenic properties (high Debye temperature and long-lived phonon modes), carbon-based materials operated as low temperature calorimeters could reach an energy threshold in the eV range and would allow for the exploration of new parameters of the DM–nucleus cross section. Despite several proposals, the possibility of operating a carbon-based cryogenic detector is yet to be demonstrated. In this contribution, the preliminary results obtained with a diamond absorber operated with a TES temperature sensor will be reported. The potential of such a detector in the current landscape of DM searches will also be illustrated.
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Operation of a Diamond Cryogenic Detector for Low-Mass Dark Matter Searches
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10.1007/s10909-020-02350-4
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2020-05-01
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We present the noise performance of high electron mobility transistors (HEMT) developed by CNRS/C2N laboratory. Various HEMT’s gate geometries with 2 pF to 230 pF input capacitance have been studied at 4 K. A model for both voltage and current noises has been developed with frequency dependence up to 1 MHz. These HEMTs exhibit low dissipation, excellent noise performance and can advantageously replace traditional Si-JFETs for the readout of high impedance thermal sensor and semiconductor ionization cryogenic detectors. Our model predicts that cryogenic germanium detectors of 30 g with 10 eV heat and 20 eV $$_\mathrm{ee}$$ ee baseline resolution are feasible if read out by HEMT-based amplifiers. Such resolution allows for high discrimination between nuclear and electron recoils at low threshold. This capability is of major interest for coherent elastic neutrino scattering and low-mass dark matter experiments such as Ricochet and EDELWEISS.
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Low-Noise HEMTs for Coherent Elastic Neutrino Scattering and Low-Mass Dark Matter Cryogenic Semiconductor Detectors
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10.1007/s10909-019-02269-5
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2020-05-01
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In this study, fatigue life assessment was conducted on a KC-1 membrane, considering cryogenic operation temperature, effect of stamping, and very long service period. KC-1 membranes are produced through a process of stamping, and they make direct contact with LNG filled within a containment system at − 162 °C. The high waves that LNG carriers encounter during sailing, and even when at anchor, cause rolling motions of the hull, which result in resonant fluid motions that generate a sloshing phenomenon; such sloshing motions expose containment systems to a high level of repeated stress. To assess the very high cycle fatigue (VHCF) life of the membrane, the effects of plastic deformation and the mechanical properties of STS304L, a membrane material, were examined at cryogenic temperatures. To identify the effects of plastic deformation and cryogenic temperatures on their mechanical properties, tensile and VHCF tests were conducted at cryogenic temperatures on a sheet to which plastic strain was applied through cold-rolling. Through forming analysis, changes in the thickness and plastic strain of a membrane caused during the process of stamping were examined. The results of earlier studies that performed flow analysis and fluid–structure interaction analysis to measure the stress applied to each component of the KC-1 containment system were cited, and the VHCF life of the membrane was assessed based on the surveyed mechanical properties, and the results of forming analysis.
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Fatigue Life Assessment of KC-1 Membrane Considering the Effects of Cryogenic Temperature and Plastic Deformation
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10.1007/s12541-019-00273-z
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2020-05-01
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We show that self-absorption of photons in scintillating bolometers can differentiate phonon pulse shapes between $$\alpha$$ α (or nuclear recoil) and $$\beta /\gamma$$ β / γ signals. This enables phonon pulse shape discrimination for particle identification. We establish a detector signal model that includes self-absorption and compare the simulated phonon pulse shapes with previously reported experimental results. The model predicts increase in pulse shape difference at higher self-absorption. Based on this result, we propose a new design of scintillating bolometers using 4 $$\pi$$ π light reflectors for maximized self-absorption and only a single phonon readout, instead of light detectors that are typically employed for particle discrimination in scintillating bolometers.
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Self-absorption and Phonon Pulse Shape Discrimination in Scintillating Bolometers
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10.1007/s10909-020-02365-x
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2020-05-01
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QUBIC is a ground-based experiment aiming to measure the B-mode polarization of the cosmic microwave background. The developed instrument is an innovative two-frequency band bolometric interferometer that will operate at 300 mK with NbSi TES arrays. In this paper, we describe the fabrication process of the detectors.
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TES Bolometer Arrays for the QUBIC B-Mode CMB Experiment
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10.1007/s10909-019-02304-5
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2020-04-28
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Rapid progress of manufacturing industry intends to evolve an appropriate method to shape advanced materials, such as titanium and its alloys, with improved properties. Enhanced strength at elevated temperatures in addition to superior corrosion resistance and biocompatibility have made titanium a popular metal employed in manufacturing, petroleum, automobile, aerospace and medical industries. Although having relatively greater abundance than many metals, processing, machining and grinding of titanium are difficult. The present experimental investigation explores the effectiveness of the indigenously developed small quantity lubrication (SQL) technique using soap water along with liquid CO_2 jet cooling technique. Variations in grinding forces, surface roughness, grinding ratio, chip form and surface morphology observed indicate that applying SQL along with liquid CO_2 jet is much effective in improving grindability of Grade 5 and Grade 1 titanium alloys than dry grinding and grinding using liquid CO_2 jet alone.
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Grinding titanium alloys applying small quantity lubrication
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10.1007/s42452-020-2792-2
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2020-04-27
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Epoxy resin has been wide applied in aerospace, superconducting industries because of the high electrical insulation, excellent adhesive properties and great chemical resistance. In this paper, epoxy/AlN composites were prepared by changing the content of the flexible amine (D-230) and the diethyl toluene diamine (DETDA) from 0 to 100 wt%. The effects of different ratios of D-230 and DETDA were investigated on the mechanical and dielectric properties of epoxy/AlN composites at liquid nitrogen temperature (77 K) and room temperature (RT). The properties of the samples were characterized by flourier transformed infrared (FTIR), scanning electron microscopy and broadband dielectric spectrometer. FTIR results showed that AlN particles were successfully modified by the silane coupling agent (KH-560). Tensile testing showed that the addition of flexible diamines generally improved the elongation at break at both RT and 77 K and the tensile strength at 77 K. The introduction of D-230 led to a lower dielectric constant at cryogenic temperature than that at RT.
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Mechanical and dielectric properties at liquid nitrogen temperature of epoxy/AlN composites modified with different contents of flexible amine
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10.1007/s42452-020-2776-2
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2020-04-23
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The present work aimed to carry out the machining of EN-42 spring steel in wire electrical discharge machining with zinc-coated brass wire using distilled water as a dielectric medium. The effect of WS_2 powder added in a dielectric medium, on the metal removal rate and surface roughness has been evaluated. With the use of WS_2, the conductivity of the dielectric is found to be constantly equal to 10 S/m, which is a very promising feature. WS_2 enhances dielectric life, metal removal rate, and surface roughness significantly. The effect of cryogenically treated wire on the metal removal rate and surface roughness during machining has been carried out. Taguchi method and genetic algorithm were used to optimize machining performance measures. Both methods provide optimum parameters and target value. The results of the Taguchi method show more error as compared to the genetic algorithm. The on time can be predicted as the most significant parameter according to the Taguchi method. From the results, it is observed that higher on time shows better metal removal rate and lower on time shows a better surface finish.
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Optimization of process parameters during WEDM of EN-42 spring steel
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10.1007/s42452-020-2650-2
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2020-04-01
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Abstract Comparative studies of the properties of porous aerogels based on cerium and calcium alginates obtained by supercritical or cryogenic drying are performed. The properties of aerogels were analyzed by means of low-temperature adsorption of nitrogen, scanning electron microscopy, thermogravimetric analysis, and kinetics of sorption upon one-sided contact with a model fluid. The obtained aerogels can be recommended as materials for the creation of dressings for the drainage and treatment of exuding wounds.
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The Possibilities of Application of Porous Aerogels Based on Alginates in Wound Healing
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10.1134/S1995421220020148
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2020-04-01
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In this paper, the design and test results of a front-end cryogenic amplifier for a bolometer detector are presented. The amplifier is implemented with two low-noise Si JFETs, where the first FET is configured as a source follower amplifier and the second FET provides a high dynamic resistance to keep the voltage gain very close to unity. A 3 dB bandwidth over a wide range from DC to 10 MHz is achieved in this design. The input voltage noise density is ~ 1.9 nV/√Hz at 300 K, which further reduces to 1.6 nV/√Hz at 120 K. The flicker corner frequency observed is below 50 Hz.
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A Cryogenic Front-End Preamplifier Operating at 120 K for Bolometric Detector
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10.1007/s10909-019-02318-z
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2020-04-01
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DNA nanotechnology utilizes DNA double strands as building units for self-assembly of DNA nanostructures. The specific base-pairing interaction between DNA molecules is the basis of these assemblies. After decades of development, this technology has been able to construct complex and programmable structures. With the increase in delicate nature and complexity of the synthesized nanostructures, a characterization technology that can observe these structures in three dimensions has become necessary, and developing such a technology is considerably challenging. DNA assemblies have been studied using different characterization methods including atomic force microscopy (AFM), scanning electron microscopy(SEM), and transmission electron microscopy(TEM). However, the three-dimensional(3D) DNA assemblies always collapse locally due to the dehydration during the drying process. Cryogenic electron microscopy(cryo-EM) can overcome the challenge by maintaining three-dimensional morphologies of the cryogenic samples and reconstruct the 3D models from cryogenic samples accordingly by collecting thousands of two-dimensional(2D) projection images, which can restore their original morphologies in solution. Here, we have reviewed several typical cases of 3D DNA-assemblies and highlighted the applications of cryo-EM in characterization of these assemblies. By comparing with some other characterization methods, we have shown how cryo-EM promoted the development of structural characterization in the field of DNA nanotechnology.
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Characterization of 3D DNA Assemblies Using Cryogenic Electron Microscopy
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10.1007/s40242-020-9107-4
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2020-04-01
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Abstract The biomass of prokaryotes and fungi, organic carbon stocks, and CO_2 emission were studied in the Cryosols and Leptosols of Franz Josef Land. The highest carbon stocks were found in the Eutric Leptosols (Loamic, Humic) formed in the wind-sheltered areas (23.2 kg C/m^2 in the upper 50 cm), as well as in Turbic Cryosols (Humiс) that contained organic matter buried by cryoturbation (13.7–20.7 kg C/m^2). The number of prokaryotes varied between 0.14 and 2.10 billion cells/g of soil, and the maximum values of their biomass were found in the litter. The fungal biomass varied from tens to hundreds of mg/g of soil depending on the type of soil and biotope. The share of spores was more than a half of the total fungal biomass in 80% of cases. Spores and mycelium were mainly represented by small forms with a diameter of up to 2–3 microns. The length of the fungal mycelium ranged from 4 to 272 m/g of soil. The maximum development of fungi was observed in the lichen biocrusts and moss litters. The fungal biomass decreased exponentially with the depth of horizons, and at the same time the share of prokaryotes in microbial biomass increased by several times. The share of microbial carbon in the total organic carbon was higher in soils of barrens (the most extreme habitats among the studied ones) as compared with the soils of local tundra areas (12.7 versus 2.5%, respectively). The levels of СО_2 emission from the surface of undisturbed soils varied in the range of 1.6–91.7 mg C–CО_2/m^2 per hour and differed by tens of times between barrens and tundra areas. The studied soils are close to the soils of the Arctic tundra when compared by their carbon stocks and CO_2 emission values; however, their microbial biomass values and their distribution are close to the soils of Antarctica and hot deserts.
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Microbial Biomass, Carbon Stocks, and CO_2 Emission in Soils of Franz Josef Land: High-Arctic Tundra or Polar Deserts?
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10.1134/S1064229320040110
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2020-04-01
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Carbon fiber/glass fiber-reinforced aluminum (Al) stacks are becoming predominant in the aerospace industries owing to their synergistic effect on numerous properties obtained by the combination of metal and composite material. This necessitates an investigation work to be performed on the machining characteristics of this special category of Al stacks. This research work focuses on studying the influence of cutting speed, feed rate and machining environment on thrust force, delamination and roughness of the finished surface of hybrid Al stacks. Dry, minimum quantity lubrication (MQL), and cryogenic environments are considered in this work. The impact of cutting speed on the responses is observed to be negligible in contrast to the feed rate. Moreover, the drilling under cryogenic environment is found to improve the surface finish and mitigated the delamination, while drilling under MQL environment minimized the thrust force. Regression models are also developed to determine the output responses. High-quality holes in aluminum stacks can be obtained under cryogenic conditions over other machining environments as revealed by multi-objective optimization.
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Experimental Investigation and Parametric Optimization on Hole Quality Assessment During Drilling of CFRP/GFRP/Al Stacks
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10.1007/s40032-020-00563-w
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2020-04-01
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Microscopic imaging techniques have been developed to visualize events occurring in biological cells. Coherent X-ray diffraction imaging is one of the techniques applicable to structural analyses of cells and organelles, which have never been crystallized. In the experiment, a single noncrystalline particle is illuminated by an X-ray beam with almost complete spatial coherence. The structure of the particle projected along the direction of the beam is, in principle, retrieved from a finely recorded diffraction pattern alone by using iterative phase-retrieval algorithms. Here, we describe fundamental theory and experimental methods of coherent X-ray diffraction imaging and the recent application in structural studies of noncrystalline specimens by using X-rays available at Super Photon Ring of 8-Gev and SPring-8 Angstrom Compact Free Electron Laser in Japan.
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Methods and application of coherent X-ray diffraction imaging of noncrystalline particles
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10.1007/s12551-020-00690-9
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2020-04-01
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AISI 440C is a high carbon martensitic stainless steel, primarily used in bearing applications. For this study, one group of AISI 440C steel disks was quenched in oil and tempered. Another group was soaked in liquid nitrogen (− 196 °C) immediately after quenching for 5 h and then tempered. The resulting microstructures were analyzed as well as the rolling contact fatigue (RCF) performance using two methodologies, with and without artificial defects. It was found that the microstructural modifications generated by the cryogenic treatments did not improve significantly the RCF resistance of the material. However, this work supports the use of artificial defects as a valid methodology for conducting accelerated rolling contact fatigue experiments.
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Rolling Contact Fatigue Resistance of Cryogenically Treated AISI 440C Steel
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10.1007/s11665-020-04777-y
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2020-04-01
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The NUCLEUS experiment aims for the detection of coherent elastic neutrino-nucleus scattering at a nuclear power reactor with gram-scale, ultra-low-threshold cryogenic detectors. This technology leads to a miniaturization of neutrino detectors and allows to probe physics beyond the Standard Model of particle physics. A 0.5 g NUCLEUS prototype detector, operated above ground in 2017, reached an energy threshold for nuclear recoils of below 20 eV. This sensitivity is achieved with tungsten transition edge sensors which are operating at temperatures of 15 mK and are mainly sensitive to non-thermal phonons. These small recoil energies become accessible for the first time with this technology, which allows collecting large-statistics neutrino event samples with a moderate detector mass. A first-phase cryogenic detector array with a total mass of 10 g enables a 5-sigma observation of coherent scattering within several weeks. We identified a suitable experimental site at the Chooz Nuclear Power Plant and performed muon and neutron background measurements there. The operation of a NUCLEUS cryogenic detector array at such a site requires highly efficient background suppression. NUCLEUS plans to use an innovative technique consisting of separate cryogenic anticoincidence detectors against surface backgrounds and penetrating (gamma, neutron) radiation. We present first results from prototypes of these veto detectors and their operation in coincidence with a NUCLEUS target detector.
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NUCLEUS: Exploring Coherent Neutrino-Nucleus Scattering with Cryogenic Detectors
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10.1007/s10909-019-02283-7
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2020-04-01
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Cryogenic Rare Event Search with Superconducting Thermometers (CRESST) is a long-standing direct dark matter detection experiment with cryogenic detectors located at the underground facility Laboratori Nazionali del Gran Sasso in Italy. CRESST-III, the third generation of CRESST, was specifically designed to have a world-leading sensitivity for low-mass dark matter (DM) (less than 2 GeV/ $$\hbox {c}^{2}$$ c 2 ) to probe the spin-independent DM-nucleus cross section. At present, a large part of the parameter space for spin-independent scattering off nuclei remains untested for dark matter particles with masses below few GeV/ $$\hbox {c}^{2}$$ c 2 although many motivated theoretical models having been proposed. The CRESST-III experiment employs scintillating $$\hbox {CaWO}_{{4}}$$ CaWO 4 crystals of $$\sim$$ ∼ 25 g as target material for dark matter interactions operated as cryogenic scintillating calorimeters at $$\sim$$ ∼ 10 mK. CRESST-III first data taking was successfully completed in 2018, achieving an unprecedented energy threshold for nuclear recoils. This result extended the present sensitivity to DM particles as light as $$\sim$$ ∼ 160 MeV/ $$\hbox {c}^{2}$$ c 2 . In this paper, an overview of the CRESST-III detectors and results will be presented.
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Searches for Light Dark Matter with the CRESST-III Experiment
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10.1007/s10909-020-02343-3
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2020-04-01
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As a typically highly efficient two-phase heat transfer under cryogenic temperature range, the operation performances of cryogenic loop heat pipes (CLHPs) might be affected by the relative location of different components. A transient mathematical model is established in present work. The model validation is demonstrated by comparing the simulation results with an auxiliary loop type neon-charged CLHP (Ne-CLHP) experiment data, and a good agreement is achieved. The effect of gravity caused by different layout orientations on the Ne-CLHP operation performances are then investigated numerically. There are three operation modes, namely normal LHP mode (n-LHP), gravity-assisted LHP mode (g-LHP), and gravity thermosyphon mode (GTP), according to different layout orientations and heat loads. Under the gravity resistance condition with a positive layout inclination angle, the Ne-CLHP is operated in n-LHP. The operating temperature increases with the positive layout inclination angle, and the heat transport capacity decreases. Under the gravity assistance condition with a negative layout inclination angle, all three operation modes may occur according mainly to the primary heat load. Only the two LHP modes are simulated in the present study, which located in the range between the transition heat load from GTP to g-LHP and the heat transport capacity. The lager negative layout incline angle, the higher transition heat load and the heat transport capacity, while lower operating temperature. In addition, the gravity-independence of cross-sectional two-phase distribution in the transport lines is discussed in the frame of dominant force analysis. The modeling effort will contribute to the technology research and development, as well as the operation control of CLHPs for space and ground applications.
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Numerical Simulation on the Effects of Component Layout Orientation on the Performance of a Neon-Charged Cryogenic Loop Heat Pipe
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10.1007/s12217-019-09761-3
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2020-04-01
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In the current direct dark matter search landscape, the leading experiments in the sub-GeV mass region mostly rely on cryogenic techniques which employ crystalline targets. One attractive type of crystals for these experiments is those containing lithium, due to the fact that $$^7\hbox {Li}$$ 7 Li is an ideal candidate to study spin-dependent dark matter interactions in the low mass region. Furthermore, $$^6\hbox {Li}$$ 6 Li can absorb neutrons, a challenging background for dark matter experiments, through a distinctive signature which allows the monitoring of the neutron flux directly on site. In this work, we show the results obtained with three different detectors based on $$\hbox {LiAlO}_2$$ LiAlO 2 , a target crystal never used before in cryogenic experiments.
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Lithium-Containing Crystals for Light Dark Matter Search Experiments
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10.1007/s10909-019-02287-3
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2020-04-01
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This paper reports our results on the electrothermal modeling of cryogenic silicon bolometers with pixel pitches of 500 and 1200 µm designed for cosmic microwave background polarimetric observation in 0.6 mm and 1.5 mm bands. These detectors should provide a high responsivity, typically around 10^11 V/W, and a very low noise equivalent power (NEP) of 10^−18 W/Hz^1/2 between 50 and 100 mK. They are based on doped silicon thermometers, which exhibit a nonohmic behavior described by the “hot electron model” (HEM) at very low temperature under high bias currents. We compare this model to the experimental characterization of these thermometers at cryogenic temperatures to confirm that the HEM is governing their electrical characteristics and their sensitivity at very low temperature. Finally, this model is used to derive the simulated responsivity and NEP performances of the pixels under weak and moderate optical power illumination.
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Design, Simulation and Fabrication of Highly Sensitive Cooled Silicon Bolometers for Millimeter-Wave Detection
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10.1007/s10909-020-02405-6
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2020-04-01
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A convincing observation of neutrino-less double beta decay ( $$0\nu {\hbox {DBD}}$$ 0 ν DBD ) relies on the possibility of operating high-energy resolution detectors in background-free conditions. Scintillating cryogenic calorimeters are one of the most promising tools to fulfill the requirements for a next-generation experiment. Several steps have been taken to demonstrate the maturity of this technique, starting from the successful experience of CUPID-0. The CUPID-0 experiment collected 10 kg year of exposure, running 26 ZnSe crystals during 2 years of continuous detector operation. The complete rejection of the dominant alpha background was demonstrated, measuring the lowest counting rate in the region of interest for this technique. Furthermore, the most stringent limit on the $$^{82}{\hbox {Se }}0\nu {\hbox {DBD}}$$ 82 Se 0 ν DBD was established. In this contribution, we present the final results of CUPID-0 Phase I.
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Final Results of the CUPID-0 Phase I Experiment
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10.1007/s10909-020-02382-w
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2020-04-01
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Systematic studies with a sapphire bolometer test setup, made with indigenously made NTD Ge sensor, are carried out. A C++ and ROOT-based pulse analysis program implementing Savitzky–Golay filtering technique for analyzing the bolometer signal is discussed. Response of the bolometer subject to heater pulses of energy equivalent of 0.3–5 MeV is presented in the temperature range of 10–100 mK. The energy resolution is found to be 15 ± 3 keV in the temperature range of 15–25 mK. It is observed that the energy resolution of the bolometer is nearly constant $$\sim \,15\,\pm $$ ∼ 15 ± 3 keV over the energy range of 0.3–5 MeV. Performance of the bolometer with the addition of a moderate-size tin sample ( $$\sim $$ ∼ 0.6 g) to the sapphire substrate is presented. The impact of vibration on the bolometer is also discussed.
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Systematic Studies of a Sapphire Bolometer with Phonon Pulses in the Temperature Range of 10–100 mK
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10.1007/s10909-019-02266-8
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2020-04-01
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Hybrid manufacturing, which, e.g., combines additive manufacturing with conventional machining processes, can be a way of overcoming limitations currently encountered in additive manufacturing. Cryogenic milling might be a viable option for hard-to-cut materials, as it leaves a contamination-free surface and can increase surface quality and tool life compared to conventional cooling concepts. In this study, the influence of cryogenic milling with carbon dioxide on titanium Ti-6Al-4V specimens manufactured with laser metal deposition (LMD) was investigated regarding tool wear and surface integrity in comparison to dry machining and machining with cooling lubricants. Moreover, additional layers of material were deposited on top of conventionally and cryogenically machined surfaces by means of LMD. The interface zone was then examined for defects. The milling process was closely monitored by means of thermal and high-speed imaging. Optical and tactile surface analysis provided evidence that lower roughness values and improved surface qualities could be obtained with cryogenic machining in comparison to dry machining. Moreover, significantly less tool wear was observed when a cryogenic cooling medium was applied. Although the utilization of conventional cooling lubricants resulted in satisfying surface qualities, substantial residual contamination on the milled surface was detected by means of fluorescence analysis. These contaminants are suspected to cause defects when the next layer of material is deposited. This is supported by the fact that pores were found in the weld bead applied on top of the milled specimens by means of LMD. Conversely, cryogenic machining resulted in very clean surfaces due to the residue-free evaporation of the coolant. Hence, a good metallurgical bonding between the weld bead and the milled substrate could be achieved. The results indicate the great potential of cryogenic milling in hybrid manufacturing, especially in terms of intermediate machining, as it provides residue-free surfaces for subsequent material deposition without an additional cleaning step and can significantly prolongate tool life.
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Hybrid manufacturing of titanium Ti-6Al-4V combining laser metal deposition and cryogenic milling
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10.1007/s00170-020-05212-1
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2020-04-01
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We present a strip transition-edge sensor microcalorimeter linear array detector developed for energy dispersive X-ray diffraction imaging and Compton scattering applications. The prototype detector is an array of 20 transition-edge sensors with absorbers in strip geometry arranged in a linear array. We discuss the fabrication steps needed to develop this array including Mo/Cu bilayer, Au electroplating, and proof-of-principle fabrication of long strips of $$\hbox {SiN}_{x}$$ SiN x membranes. We demonstrate minimal unwanted effect of strip geometry on X-ray pulse response and show linear relationship of 1/pulse height and pulse decay times with absorber length. For the absorber lengths studied, our preliminary measurements show energy resolutions of 40–180 eV near 17 keV. Furthermore, we show that the heat flow to the cold bath is nearly independent of the absorber area and depends on the $$\hbox {SiN}_{x}$$ SiN x membrane geometry.
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Development of Transition-Edge Sensor X-ray Microcalorimeter Linear Array for Compton Scattering and Energy Dispersive Diffraction Imaging
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10.1007/s10909-019-02267-7
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2020-03-27
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The virgin thermoplastics have numerous applications in fused deposition modelling (FDM) process. Commercially, different thermoplastics are recycled through extrusion (without any reinforcement as primary (1°) recycled materials) for enhancing their reusability and sustainability. However, hitherto very little has been reported on mechanical and thermal properties of cryogenic (cryo) milled 1° recycled ABS (to be used on FDM-based 3D printer). In the present research article the cryo ball milling of 1° recycled ABS thermoplastic has been reported to explore the influence of cryo environment (−196 °C) on mechanical, thermal and surface properties of the ABS-based feed stock filament (prepared through screw extrusion) for further use on commercial FDM set-up (without any hardware/software change). The process parameters of cryo-milling (like frequency of vibration, milling time and grinding media weight) have been selected for investigations using Taguchi-based design of experiment (DOE). The study results show significant improvement in peak strength (PS) of the cryo-milled ABS in comparison with non-cryo-milled ABS without any degradation of thermal properties (mainly heat capacity). As regards the process parameters of cryo-milling, 30-Hz frequency, 15-min milling time and 32-g media weight are the best settings for maximum PS. The maximum value of PS observed was 61.32 MPa. The optical photomicrographs supported with 3D rendered images were captured to support the surface characteristics and porosity level in the wires (to be used as feed stock filament for FDM) prepared with cryo-milled ABS (powder samples).
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On mechanical and thermal properties of cryo-milled primary recycled ABS
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10.1007/s12046-020-1317-4
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2020-03-19
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The Accelerator Driven Sub-critical (ADS) system is a strategic plan to solve the nuclear waste problem for nuclear power plants in China. High-energy particle accelerators and colliders contain long strings of superconducting devices, superconducting radio frequency cavities, and magnets, which may require cooling by 2 K superfluid helium (Helium II). 2 K superfluid helium cryogenic system has become a research hot spot in the field of superconducting accelerators. In this study, the ADS Injector-I 2 K cryogenic system is examined in detail. The cryogenic system scheme design, key equipment, and technology design, such as the 2 K Joule–Thomson (J–T) heat exchanger and cryomodules CM1 + CM2 design, are examined, in addition to the commissioning and operation of the cryogenic system. The ADS Injector-I 2 K cryogenic system is the first 100 W superfluid helium system designed and built independently in China. The ADS proton beam reached 10 MeV at 10 mA in July 2016 and 10 MeV at 2 mA in continuous mode in January 2017 and has been operated reliably for over 15,000 h, proving that the design of ADS Injector-I 2 K cryogenic system, the key equipment, and technology research are reasonable, reliable, and meet the requirements. The research into key technologies provides valuable engineering experience that can be helpful for future projects such as CI-ADS (China Initiative Accelerator-Driven System), SHINE (Shanghai High Repetition Rate XFEL and Extreme Light Facility), PAPS (Platform of Advanced Photon Source Technology), and CEPC (Circular Electron-Positron Collider), thereby developing national expertise in the field of superfluid helium cryogenic systems.
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ADS Injector-I 2 K superfluid helium cryogenic system
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10.1007/s41365-020-0742-8
|
2020-03-01
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Abstract This paper presents the results of studies of the time and spectral characteristics of phosphorescence in organic compounds cooled to cryogenic temperatures. The data obtained after the analysis make it possible to propose a physical mechanism of excitation of long-term phosphorescence and assess the prospects for creating new active laser media (based on an analog of the Shpolsky matrix).
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The Time Characteristics and Phosphorescence Spectra of Cooled Carbon-Containing Analogues of the Shpolsky Matrix
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10.3103/S0027134920020022
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2020-03-01
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A predictive thermal analytical model based on the improved Oxley’s theory and the image heat source method for orthogonal cutting was proposed to obtain the exact temperature distributions in the chip, tool, and workpiece during cryogenic machining. The influences of some important factors, including the shear deformation at primary zone, the friction at tool-chip interface, and the heat losses at both rake and flank faces of the tool caused by liquid nitrogen jetting, were all considered in the thermal model. The heat loss of rake face was divided into contact and non-contact zones to calculate the cooling effects at different positions. Heat partition ratios were utilized to modify the non-uniform distribution at tool-chip interface for all the heat sources and losses, respectively. The cutting parameters were optimized to avoid the low precision and efficiency of iterative algorithm. Cryogenic turning experiments were performed to verify the analytical model of temperature distribution. The results showed that the average errors of the predicted temperatures were lower than 3.30%.
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Modeling of temperature distribution in turning of Ti-6Al-4V with liquid nitrogen cooling
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10.1007/s00170-020-05093-4
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2020-03-01
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The high speed machining process is considered as one of the manufacturing technologies more prone to increase the productivity. The increasing interest in this manufacturing process is also due to the good surface quality (e.g. low roughness) as well as the significant alteration of the subsurface (improved hardness and microstructure refinement) of the machined parts. This paper describes the metallurgical phenomena occurring during high speed turning performed under dry and cryogenic conditions on aluminium alloy AA7075 T6 and investigates their effects on the surface integrity. Two cutting parameters, namely cutting speed and feed rate, were varied to induce surface and subsurface changes, such as microstructure and surface topography variation as well as mechanical properties modifications. The surface integrity was analysed through optical microscopy, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), X-ray diffraction (XRD), surface roughness and micro-hardness measurements.
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Surface and subsurface modifications of AA7075-T6 induced by dry and cryogenic high speed machining
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10.1007/s00170-020-05108-0
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2020-03-01
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Cryogenic treatment is a supplementary heat treatment which can be applied to many different alloys. The effects of treatment are permanent and affect the entire material section. There have been many studies focused on the cryogenic treatment of tool steels. In the current study, an annealed Ti6Al4V material was used, and different cryogenic treatment processes and aging were applied. The effects of different heat treatment procedures on the microstructural and tribological properties were investigated. Eight different structures were obtained with different heat treatment cycles. As a result of wear tests and hardness tests, both cryogenic treatment and the aging treatment improved the wear resistance. The results of the ball-on-disk wear tests showed that the cryo-treated and aged samples have better wear resistance than annealed and shallow cryo-treated samples. 24 h deep cryogenic treatment improved wear resistance of the Ti6Al4V sample without significantly affecting hardness. It was also found that the aging process was effective due to both increasing hardness and wear resistance. Applying additional cryogenic treatment between solutionizing and aging improved this effect.
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Tribological Properties of Cryo-Treated and Aged Ti6Al4V Alloy
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10.1007/s12666-020-01898-9
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2020-03-01
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Abstract The milling of molybdenite under cryogenic conditions in argon has been performed for the first time, and the physicochemical properties of its samples, their catalytic activity in model reactions of hydrodesulfurization of dibenzothiophene and diesel components, and the ability to initiate the isopropylbenzene oxidation reaction have been studied. The samples have been found to exhibit high catalytic activity.
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Influence of Conditions of Cryogenic Molybdenite Grinding on the Activity of Bulk Sulfide Hydrotreating Catalysts
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10.1134/S0965544120030147
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2020-03-01
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Obtaining a high specific capacity of Sn-Ti composite anode for lithium-ion batteries while maintaining stable cycle is a key issue to be solved. Research on using reasonable compensation treatment is of importance for solving the problem. In this work, the Sn-Ti-C nanofibers are prepared by electrospinning and using deep cryogenic treatment as supplementary treatment and then carbonization. After the deep cryogenic treatment, the abundant grain boundaries are introduced into Sn particles, which more easily combine with Ti to form Sn-Ti particles in the process of high-temperature carbonization. The Sn-Ti particles inside and outside the grooved nanofibers with low Ti content inhibits the volume expansion of Sn during the cycles and maintains the high specific capacity for Sn alloy. For the sample as the anode, the capacity can remain at 557 mAh g^−1 and the capacity retention of 98.7% over 100 cycles. The improvement of electrochemical performance can be simply implemented by deep cryogenic treatment, which provides reliable theoretical and practical data for the preparation of Sn-Ti composite anode for lithium-ion batteries.
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Performance enhancement of Sn-Ti-C nanofibers anode for lithium-ion batteries via deep cryogenic treatment
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10.1007/s10008-020-04519-z
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2020-02-27
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A honeycomb structure is widely used in sandwich structure components in aeronautics and astronautics; however, machining is required to reveal some of its features. In honeycomb structures, deficiencies, such as burrs, edge subsiding, and cracking, can easily appear, owing to poor specific stiffness in the radial direction. Some effective fixation methods based on a filling principle have been applied by researchers, including approaches based on wax, polyethylene glycol, iron powder, and (especially) ice. However, few studies have addressed the optimization of the cutting parameters. This study focused on optimizing the cutting parameters to obtain a better surface roughness (calculated as a roughness average or R _a) and surface morphology in the machining of an aluminum alloy honeycomb by an ice fixation method. A Taguchi method and an analysis of variance were used to analyze the effects and contributions of spindle speed, cutting depth, and feed rate. The optimal cutting parameters were determined using the signal-to-noise ratio combined with the surface morphology. An F-value and P-value were calculated for the value of the R _a, according to a “smaller is better” model. Additionally, the optimum cutting parameters for machining the aluminum honeycomb by ice fixation were found at different levels. The results of this study showed that the optimal parameters were a feed rate of 50 mm/min, cutting depth of 1.2 mm, and spindle speed of 4000 r/min. Feed rate was the most significant factor for minimizing R _a and improving the surface morphology, followed by spindle speed. The cutting depth had little effect on R _a and surface morphology. After optimization, the value of R _a could reach 0.218 μm, and no surface morphology deterioration was observed in the verified experiment. Thus, this research proposes optimal parameters based on ice fixation for improving the surface quality.
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Surface Quality Improvement in Machining an Aluminum Honeycomb by Ice Fixation
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10.1186/s10033-020-00439-1
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2020-02-01
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Cryogenic diamond burnishing is an impactful method to enhance the functional performance of the product. In this article, an experimental study on the diamond burnishing of 17-4 precipitation hardenable stainless steel in a cryogenic cooling condition has been presented. This material has excellent corrosion resistance, high strength and enormous applications in the manufacturing industries. The control variables were namely burnishing force, burnishing feed and burnishing force have been studied and modeled for the output responses explicitly surface hardness and surface roughness. The influence of control variables on performance features has been analyzed using response surface graphs. The significant influence of burnishing conditions on the output responses was established by analysis of variance. Desirability function approach has been employed to optimize the multi-performance characteristics. At the corresponding highest desirability, the optimal process parameter combination was found to be burnishing feed = 0.053 mm/rev, burnishing speed = 31.29 m/min and burnishing force = 200 N which yields a minimum surface roughness = 0.199 µm and maximum surface hardness = 397.48 HV. The maximum percentage of error among the predicted and experimental results was found to be 10% and 2%, respectively, for surface roughness and surface hardness. The investigational findings were observed to be in agreement with the predicted value with permissible deviation.
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Application of Desirability Approach to Optimize the Control Factors in Cryogenic Diamond Burnishing
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10.1007/s13369-019-04326-3
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