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2020-02-01
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The interface distribution and self-pressurization phenomenon are the most important problems in the storage of cryogenic liquid on orbit, which are difficult to be predicted and assessed exactly due to the complex non-equilibrium thermal behavior. In this paper, one 3-D CFD model based on volume of fluid (VOF) method is established to investigate the interface evolution and self-pressurization process in the liquid oxygen (LOX) tank in microgravity environment with various heat loads and gravitational accelerations. The validity of the model is verified by both the present ground experiments and the drop tower experiments from literature. The impact of microgravity on the gas-liquid interface distribution in the cryogenic tank is analyzed. Different from the ground condition, the distribution behavior of the gas-liquid two-phase fluid in microgravity is that the liquid is covering the tank wall, and the ullage is staying at the top of the tank surrounded by the liquid. Then the pressurization rate of the tank with different gravitational accelerations is obtained. The tank pressure rise rate increases with the reducing of the gravity. The results are beneficial to the optimal design of the cryogenic propellant tank.
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Numerical Simulation on Interface Evolution and Pressurization Behaviors in Cryogenic Propellant Tank on Orbit
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10.1007/s12217-019-09734-6
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2020-02-01
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In modern manufacturing industries, the importance of multi-objective optimization cannot be overemphasized particularly when the desired responses are differing in nature towards each other. With the emergence of new technologies, the need to achieve overall efficiency in terms of energy, output, and tooling is on the rise. Resultantly, endeavor is to make the machining process sustainable, productive, and efficient simultaneously. In this research, the effects of machining parameters (feed, cutting speed, depth of cut, and cutting condition including dry, wet, and cryogenic) were analyzed. Since sustainable production demands a balance between production quality and energy consumption, therefore, response parameters including specific cutting energy, tool wear, surface roughness, and material removal rate were considered. Taguchi-gray integrated approach was adopted in this study. Multi-objective function was developed using gray relational methodology, and its regression analysis was conducted. Response surface optimization was carried out to optimize the formulated multi-objective function and derive the optimum machining parameters. Concurrent responses were optimized with best-suited values of input parameters to make the most out of the machining process. Analysis of variance results showed that feed is the most effective parameter followed by cutting condition in terms of overall contribution in multi-objective function. The proposed optimum parameters resulted in improvement of tool wear and surface roughness by 30% and 22%, respectively, whereas specific cutting energy was reduced by 4%.
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Multi-objective optimization of turning titanium-based alloy Ti-6Al-4V under dry, wet, and cryogenic conditions using gray relational analysis (GRA)
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10.1007/s00170-019-04913-6
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2020-02-01
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The aramid fiber–reinforced composite (AFRP) has special the structure and physical properties. Although, the dry helical milling hole method could improve the machining precision and reduce the cutting force for AFRP. There were still some problems such as hole defects, limited hole depth, and low machining efficiency. In this paper, the tool cutting point trajectory model based on sample and tool coordinate system was established. The cutting force model of milling hole considering fiber orientation was constructed. A series of cryogenic cooling milling hole tests were carried out using liquid nitrogen internal jet cutting equipment. The results show that the cutting path and cutting force are mainly related to axial feed, tangential feed, and center distance between tool and hole axis. Similarly, type I and II defects are serious at low-speed dry milling hole, as well as obvious type III ablative defects at high speed. Compared with dry milling hole, the cutting force in cryogenic cooling is greater at the same cutting speed. And the influence of tool axial feed on axial force and tangential force is larger than that of tangential feed. Meanwhile, the property changes of resin base and composite in cryogenic are the main reasons for inhibiting type I and II milling hole defects. Furthermore, the cryogenic medium cooling is the reasons for inhibiting type III defects, as well as passivation and adhesion of tool side edge and flank. So the cryogenic cooling milling method can improve milling hole effect and restrict machining defects for AFRP.
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Research on milling hole of AFRP based on cryogenic cooling processing
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10.1007/s00170-020-05057-8
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2020-01-22
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In the present investigation, dissimilar materials such as AA6063 and SS304L having pipe dimensions of 60.33 mm outer diameter and 3.9 mm wall thickness were friction-welded with different conditions of process parameters. Nondestructive tests such as radiography test (RT) and liquid penetration test (LPT) were carried out on the welded pipes in order to qualify weld joint. Thermal shock test and helium leak tests were performed on the successful welded samples in order to check its ability to work with cryogenic application. The results revealed that the pipe-to-pipe configuration of dissimilar Al–SS joints was produced successfully by friction welding using continuous drive. There were no defects presented in the joint area as revealed by RT and LPT. Thermal shock test and helium leak tests have also confirmed the soundness of joints. Higher deformation of Al base material results in the huge flash formation of Al that results in the sleeve formation of Al pipe on SS pipe. The helium leak test has confirmed the soundness of joints without any defects after its testing at 1.2 psi pressure. More than 60% of joint efficiency was obtained from Al–SS friction-welded joints.
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Pipe-to-pipe friction welding of dissimilar Al-SS joints for cryogenic applications
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10.1007/s40430-020-2181-1
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2020-01-02
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Cryogenic wind tunnel is a sophisticated aerodynamics ground test facility, which operates in cryogenic temperature with injection of liquid nitrogen. The multi-variable, nonlinear and coupled dynamics existing between the temperature, pressure and Mach number in the tunnel, poses great challenges for the effective control of the tunnel. L _1 adaptive control is a new control methodology developed in recent years with good robustness properties, which has good potentials to address these challenges. But this control method does not provide full adaptive feedforward control in its generic structure. In the paper, adaptive feedforward control action is introduced into the standard L _1 adaptive control architecture for nonlinear systems in the presence of matched un-modeled dynamics. This new control structure is applied to the stagnation pressure control in a cryogenic wind tunnel, which could also be used for the control of temperature and Mach number in the tunnel. This new method could effectively compensate known disturbances with linear gain uncertainty, which occur in the nonlinear systems, while retaining the closed-loop control performance of L _1 adaptive control. After the proof and discussions on the stability of this method, simulations of the stagnation pressure control in the wind tunnel are presented. The results and analysis demonstrate the effectiveness of the proposed control architecture.
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Nonlinear L_1 adaptive control of stagnation pressure in a cryogenic wind tunnel
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10.1186/s42774-019-0024-5
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2020-01-01
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Up to now, machines have been considered as theoretical components fulfilling a function. It is interesting to understand how they operate, what are their operating domains and what is their efficiency. Some of them have to operate in very different regimes during the cool-down and warm-up phase. This chapter considers mainly oil lubricated compressors, oil management system (including oil removal), heat exchangers, cryogenic expansion turbines and cryogenic centrifugal compressors, circulators and pumps.
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Technology of Components
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10.1007/978-3-030-51677-2_6
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2020-01-01
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Mechanical properties of materials are highly sensitive to temperature changes. In-situ characterization approach can be utilized to probe temperature dependence of the mechanical properties at multiple length scales. This chapter introduces the principles and techniques for high- and low-temperature mechanical testing with simultaneous real-time imaging. Temperature-dependent characterization requires specialized instrumentation which allows for effective sample heating or cooling. Challenges associated with thermal drift, system compliances, thermal expansion, radiation, and image quality are addressed from the standpoint of high-temperature in-situ instrumentation design. Strategies to overcome or minimize these issues are discussed in the chapter. The chapter discusses in-situ temperature-dependent characterization by indentation, compression, flexural, and tensile testing techniques. The transition in deformation characteristics in different temperature regimes is presented through case studies. Mechanical characterization at different temperatures is helpful to decipher plasticity parameters, such as Peierls stress or activation energy. The applications of high-temperature testing for in-situ observation of creep mechanisms, fatigue deformation, and temperature-dependent fracture behavior of thin films are presented in the chapter. The high- and low-temperature in-situ testing is also shown to be useful for selectively activating and studying different slip systems in materials. Therefore, in-situ testing as a function of temperature is a promising approach for engineering superior materials with extreme environment applications.
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In-Situ Mechanical Characterization as a Function of Temperature
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10.1007/978-3-030-43320-8_4
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2020-01-01
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A new generation launch vehicle developed by ISRO consists of solid, liquid, and cryogenic stages. Cryogenic stage uses liquid oxygen and liquid hydrogen as oxidizer and fuel, respectively, for propulsion. Fuel and oxidizer are stored in cylindrical tanks with tori-spherical end domes. When the above fluids get depleted from the tanks, dip formation in the liquid surface and subsequent ullage gas entry into the outlet occurs. Formation of surface dip and subsequent gas entry into the outlet is governed by either sink potential phenomenon or vortex phenomenon or combination of both. This could lead to malfunction of the liquid rocket engine. Critical height of propellant from the tank bottom is defined as the elevation at which surface dip forms. Hence, the estimation of critical height is very important in order to quantify unused propellant toward the end of the thrusting phase. Two-phase flow due to vortex can be eliminated by providing either anti-vortex baffle or wire mesh/filter. But it cannot be eliminated due to sink phenomenon unless the outlet is properly designed. Oxidizer tank is provided with a siphoning feed line with wire mesh on the upstream of the inlet to supply contaminant-free liquid oxygen to engine. Published literature on siphoning feed line for the estimation of critical height is very limited. In addition to the above, information on effect of pressure drop due to the presence of wire mesh in the flow path on critical height is also not available. Numerical analysis is carried out using ANSYS CFD software to estimate the critical height for the above siphoning feed line with wire mesh. In order to verify the modeling of wire mesh, two different fluid models (without wire mesh and with wire mesh having zero pressure drop) are used. Oxidizer and gas contained in the tank are idealized as incompressible viscous fluids. Time-dependent Reynolds Averaged Navier Stokes (RANS) equations with continuity and volume fraction equations are solved to estimate the height at which surface dip forms. Numerical simulations are repeated using the fluid model with wire mesh for different pressure drops across it in order to find its effect on critical height. Pressure drop across a wire mesh is due to reduced flow area and is dependent on wire mesh size, density, viscosity, and velocity of fluid. From the numerical investigations, it is found that the presence of wire mesh in the flow path at the upstream of siphoning feed line results in higher critical height due to pressure drop across it. Hence, it is recommended to relocate the wire mesh to the inlet of the siphoning feed line. Another important conclusion is that radial velocity at the inlet of siphoning feed line should be low so that the liquid till its inlet can be utilized. This can be achieved by increasing the bell mouth diameter of the siphoning feed line.
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Numerical Study of Effect of a Wire Mesh on Fluid Depletion Characteristics of a Cryogenic Propellant Tank
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10.1007/978-981-15-1892-8_7
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2020-01-01
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The present work deals with the influence of cryogenic coolants LN_2 delivered through holes made on flank surface and rake surface of tungsten carbide cutting tool inserts in turning of super duplex stainless steel (SDSS) using in-house developed cryogenic setup. Experiments were conducted with the cryogenically treated tool, cryogenically treated tool with tempering and cryogenic coolant directly passed through a modified cutting tool insert. Results are compared with dry cutting conditions. The cutting conditions are low feed rate/high depth of cut, medium feed rate/medium depth of cut, and high feed rate/low depth of cut. The material removal rate and cutting speed is kept constant under all three cutting conditions. Microstructural study of the tool as received and cryogenically treated is examined using SEM. The population of harder tungsten carbide phase (gamma phase) is found to be more in the cryogenically treated tool. Due to tempering, the hardness of insert is improved by 8% which in turn increased tool life. By direct supply of LN_2 through modified cutting tool increased tool life by 23%, more than the cryogenically tempered tool. There are no appreciable changes in the temperature of the cutting tool under dry cutting and cryogenically treated inserts. However, there is a large difference observed in temperature of cutting tool when LN_2 is supplied through a modified insert directly, which in turn yielded high tool life.
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Process Capability Improvement Using Internally Cooled Cutting Tool Insert in Cryogenic Machining of Super Duplex Stainless Steel 2507
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10.1007/978-981-15-2696-1_31
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2020-01-01
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Deep cryogenic treatment (DCT) and secondary tempering for 40CrNiMoA steel were carried out to obtain the desirable microstructures corresponding to excellent mechanical properties suiting for the preparation of flex spline of harmonic drive reducer. The effects of DCT and secondary tempering on microstructural characteristics and mechanical properties were investigated by x-ray diffraction, scanning electron microscopy, electron backscattered diffraction and transmission electron microscopy, in association with property measurements. The results show that the DCT promotes the transformation of retained austenite to martensite, the precipitation and homogeneous distribution of carbides as well as the refinement of martensitic substructures. The structural and morphological changes significantly improve the hardness, yield and tensile strength of steels, but slightly lower the elongation of them. Further secondary tempering at special temperatures can successively increase the elongation and fracture toughness of the DCT-treated 40CrNiMoA steels at the cost of slight decrease in hardness and strength due to the reduction in dislocation density. Therefore, the DCT in combination with secondary tempering can improve the comprehensive mechanical properties of 40CrNiMoA steels to produce the flex spline with a higher lifetime.
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Influence of Deep Cryogenic Treatment and Secondary Tempering on Microstructure and Mechanical Properties of Medium-Carbon Low-Alloy Steels
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10.1007/s11665-019-04532-y
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2020-01-01
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This paper focuses on a new methodology, superconducting sensor for the estimation of gravitation perturbations, optical interferometer, and applied software that are capable to realize the method under the noise influence. This paper is oriented on the development of a cryogenic sensitive element with an accuracy of about 10^−10 g. This sensor can be used for the analysis of geodynamical processes and for the accumulation of experimental data under various conditions, which is of importance in order to develop future methods.
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Superconducting Gravimeters Based on Advanced Nanomaterials and Quantum Neural Network
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10.1007/978-94-024-2030-2_15
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2020-01-01
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Biogas, an ultimate renewable energy, is of enormous demand currently, due to increased fuel price and its fluctuations with expansive pollution emission. Biogas is environmentally feasible and viable. Biomethane production is of high impact, and hence the present chapter is concentrated on various biogas upgradation technologies conjugated with carbon dioxide and hydrogen sulphide removal strategies. The upgrading methods such as absorption, adsorption, membrane separation, biological methods, cryogenic technology, hybrid methods, supersonic separation, industrial lung, in situ methane enrichment and chemical dehydrogenation are discussed. High methane purity with minimized methane loss is the key for an effective upgradation method. A comprehensive study of comparison between various biogas upgradation technologies is analysed, showcasing the advantages and disadvantages too. It is concluded that the recently innovated technologies have wide potential advantages than the conventional biogas upgrading technologies. Although innovated technologies are so far better, detailed analysis, research and development is required for acquiring a technology which is economically, environmentally, technologically, operationally and socially feasible and acceptable.
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Recent Trends in Biogas Upgrading Technologies for Biomethane Production
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10.1007/978-981-13-8637-4_9
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2020-01-01
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Biogas production has materialized as an auspicious technology for the conversion of renewable energy sources such as agricultural, animal, industrial and municipal wastes into a beneficial form of energy. Biogas production is a very attractive and changeling task because of its slower degradation and requires higher retention time via anaerobic digestion (AD) process. Additionally, there is a chance of toxic intermediates in some of these feedstock may result in the decline of the biogas production process. This Biogas technology can be integrated with various strategies to mitigate the environmental pollution. high availability and low cost of these feedstocks promote new strategies for the minimization of waste. Considerable efforts in chic research are undertaken in order to upgrade the composition of the feedstock, efficiency in terms of fuel property and flexibility of biogas production to enhance the economic viability of biogas plants. Along with the methane, biogas consists of various compounds like CO_2, H_2S, water vapor, nitrogen, hydrogen and oxygen which tend to pull down the calorific value when compared with natural gas. Absorption, adsorption, cryogenic method and membrane-based gas permeation are several technologies employed to increase the fuel property of biogas.
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Enhancement of Feedstock Composition and Fuel Properties for Biogas Production
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10.1007/978-981-15-0410-5_9
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2020-01-01
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During the last two decades, a considerable effort has been dedicated to engineer resonant tunneling transport within the family of III-Nitride semiconductors. At the heart of this initiative, lies the outstanding material properties that this revolutionary family of semiconductors offers for manufacturing high-power ultra-fast oscillators and terahertz quantum cascade lasers that operate at room temperature. Despite these efforts, it is only recently that room temperature resonant tunneling transport has been demonstrated within III-Nitride materials. In this chapter we discuss various aspects of heterostructure design, epitaxial growth and device fabrication, which have led to the first unequivocal demonstration of robust resonant tunneling transport, and reliable room temperature negative differential conductance resulting in the generation of GHz oscillations in III-Nitride semiconductors. These advances allowed us to shed light into the physics of resonant tunneling transport in polar semiconductors which had remained hidden until now. This insight was obtained using a combined experimental and theoretical approach, leading to the discovery of new tunneling features, unique in polar RTDs. After identifying the intimate connection between the polarization fields and the resonant tunneling current, we harness this relationship by introducing a completely new approach to measure the magnitude of these internal polarization fields. Moreover, precise epitaxial growth at the single-monolayer level is employed to engineer resonant tunneling currents >200 kA/cm^2 and demonstrate the first microwave oscillator driven by a GaN/AlN resonant tunneling diode. The findings presented in this chapter pave the way for the realization of III-Nitride-based high-speed oscillators and quantum cascade lasers that operate at wavelengths that remain unreachable by other semiconductor materials.
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Resonant Tunneling Transport in Polar III-Nitride Heterostructures
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10.1007/978-3-030-20208-8_8
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2020-01-01
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Frost heaving is a challenge for geotechnical engineers who deal with transportation infrastructure in a cold climate. To make a frost heave forecast and access reliability of soil masses engineers apply different numerical soil models calibrated by results of in-situ and numerical simulation tests. The recently developed frozen/unfrozen soil model by PLAXIS bv and NTNU was used for reproduction of laboratory and field tests data. The model describes frost heaving as a function of frost front moving rate and water migration rate from unfrozen zone and has 25 parameters: 7 general ones, 12 parameters that are responsible for solid strains, 3 parameters responsible for suction strains and 3 ones that account for coupling effects between the variation of the solid phase stresses and the cryogenic suction. The results of oedometer tests of silt in the unfrozen and frozen states and frost heave tests, presented in the article, allow us to obtain such parameters as initial segregation threshold value, elastic and elasto-plastic compressibility coefficients, rate of change in Young’s modulus with temperature. But we have to apply backward analysis in order to obtain a best-fit of simulated results with test results. Unfortunately, most parameters is to be obtained by only calibration method. Additionally, to validate the frozen and unfrozen soil model the results of geotechnical monitoring of the cold-storage building are used. The frost heave phenomenon was appeared for 29-years period of its operation. Results of in-situ monitoring and numerical simulation showed good correlation with depth of frost penetration but unsatisfied results of frost heave deformations.
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Calibration of PLAXIS Frozen/Unfrozen Soil Model According to Results of Laboratory Tests and In-situ Monitoring
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10.1007/978-981-15-0454-9_12
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2020-01-01
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Recent developments in applications such as high-temperature superconducting magnets, infrared detectors, and electronics components have led to an alarming increase in heat dissipation rate, which now far exceeds the capability of conventional heat pipe cooling systems. This trend is responsible for a recent transition to flat plate oscillating heat pipes. A new flat plate cryogenic oscillating heat pipe (FPC-OHP) has been developed and validated through experimentations. The performance evaluation of FPC-OHP was investigated with temperature measurements. FPC-OHP consisted of evaporator, condenser, and adiabatic section with the dimensions of 93 × 70 × 8 mm^3. The FPC-OHP was made of copper alloy and fabricated by a vertical milling machine, having square channels with a hydraulic radius of 0.66 mm. Liquid nitrogen was used as a working fluid with a charge ratio of 60%. Experimental results revealed the maximum heat transport capability up to 300 W. Moreover, the thermal resistance decreased from 0.25 to 0.11 K/W corresponding to an increase in the heat load from 25 to 300 W. The average temperature difference between evaporator section and condenser section reached up to 34 K for 300 W. The measured effective thermal conductivities were found to be 7353 W/m K.
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Experimental Investigation of Flat Plate Cryogenic Oscillating Heat Pipe
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10.1007/s10909-019-02243-1
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2020-01-01
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Superconducting wigglers (SCWs) were introduced about 40 years ago and since then have been extensively used at many synchrotron radiation (SR) facilities around the world. The technology of SCWs progressed significantly due to innovative designs and the use of novel materials. SCWs have been established as reliable tools and are a standard attribute of many SR facilities. They became the hard x-ray radiation source of choice for the majority of low- and medium-energy x-ray light sources. SCWs greatly increased the capabilities of these sources by extending the accessible radiation wavelength range below 1 Å. The majority of SCWs have been designed and built at Budker Institute of Nuclear Physics, Novosibirsk, Russia. Although the first superconducting undulator (SCU) was built almost at the same time as the first SCW, the progress in the development of SCUs was much slower compared with SCWs. This was mostly due to the fact that major investments went to the development and production of permanent magnet undulators. In the last two decades, there were several attempts to establish an SCU as a radiation source for an operational SR facility, but it was only relatively recently, when the SCU program was given significant funding priority at the Advanced Photon Source (APS), that SCUs attained a level of performance adequate enough to move from the research and development phase to the operational phase on a daily basis. That investment has resulted in the design and fabrication of several SCUs that are currently operating in the APS ring.
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Superconducting Wigglers and Undulators
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10.1007/978-3-030-23201-6_61
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2020-01-01
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The ALOHA software was used to calculate the leak source strength of the cryogenic ethylene tank, and the calculation results were provided to the FDS software to set up the model. The study established a basic ethylene tank leakage scenario, and the diffusion process of ethylene was simulated by means of computational fluid dynamics software (FDS), which could describe a series of physical changes in the vapor cloud diffusion process. At the same time, the influence of the relevant steam control technology of setting fire dikes with different height on the downward wind direction of ethylene vapor cloud was simulated. The simulation results show that the control technique really plays a significant role in suppressing the vapor diffusion.
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FDS Software Simulation for Control Effect of Fire Dikes on Leakage of Cryogenic Ethylene Storage Tank
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10.1007/978-981-32-9139-3_13
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2020-01-01
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Owing to poor thermal conductivity, heat dissipation, and high chemical reactivity toward most of the tool materials, temperature elevation in the machining of titanium alloy leads to poor surface quality. Based on analyzing the variation laws of the milling forces under cryogenic cooling, the present investigation concerns the surface integrity (surface roughness, micro-hardness, microstructures, and residual stresses) in cryogenic milling of Ti-6Al-4 V alloy under the application of liquid nitrogen (LN_2) as a cooling mode. Findings have indicated a dramatic increase in milling forces, and decreasing surface roughness was observed under variation of jet temperature (20~−196 °C). Besides an increase in cutting speed from 60 to 120 m/min, a linear increase in cutting forces, surface roughness, micro-hardness, and residual compressive stress was observed. The minimum micro-hardness decreased at cutting speed of 90 m/min and up to 30 μm in depth. A holistic comparison between obtained results under cryogenic milling and previously studied results under dry milling at same cutting conditions depicted higher micro-hardness and higher compressive residual stress under cryogenic LN_2 on the machined surface. However, the residual stress under LN_2 cooling conditions tends to decrease relatively slower compared to dry milling. Also, there are no significant differences in grain refinement and twisting under dry and cryogenic LN_2 machining. The research work proves the effectiveness of cryogenic milling in improving the surface integrity of the Ti-6Al-4 V alloy.
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Effect of liquid nitrogen cooling on surface integrity in cryogenic milling of Ti-6Al-4 V titanium alloy
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10.1007/s00170-019-04721-y
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2020-01-01
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The number of applications of high-temperature superconductors (HTS) in the power grid increases gradually. In order to achieve an efficient cooling system, HTS are put inside of a cryostat. In many cases the cooling medium can be used as insulation medium as well. With HTS, liquid nitrogen is an applicable cooling medium. In order to achieve safe and uninterrupted operation, liquid nitrogen has to be tested for its insulation properties in a variety of conditions, such as different pressures, temperatures and even mixtures of different states of matter. One of these properties is the breakdown voltage which is tested with a certain electrode arrangement inside a cryostat. Usually a bushing is required to apply the high voltage to the electrode setup, as cryostats are often made of metal and thus on ground potential. The bushing generally consists of a field grading, a solid insulation and a feedthrough. The testing procedure for a certain setup is often time intensive as it requires a thorough preparation prior to testing, a cooldown phase, the testing time itself and subsequently a reheating phase. Especially the cooldown phase is time intensive and done very slowly and carefully, even with rates as low as 2 K/h. This is due to the fact that the classic electric field grading and feedthrough in the bushing are usually made of metals which exhibit a different thermal contraction constant than the insulation material of the bushing. Thus, a too fast cooldown can lead to delamination between solid insulation and metal parts. In this work a bushing designed for lightning impulse voltages of up to 200 kV is presented. It features a field grading and feedthrough design which reduces the problem of different thermal contraction constants by using a specially prepared composite material. It allows for cooldown from room temperature to liquid nitrogen temperatures (ΔT ≈ 200 K) in approximately 90 min, which represents a rate of 133 K/h. It has been tested extensively in the high voltage lab with AC peak voltages up to 170 kV and has been subjected to vibrations. Furthermore, partial discharge tests at commissioning have been done to deduce the partial discharge behaviour.
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Bushing for a Liquid Nitrogen Cryostat - A Novel Field Grading Material
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10.1007/978-3-030-31680-8_30
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2020-01-01
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The simulation of cryogenic flows in rocket combustion chambers is challenging because we have to consider a reactive mixture over a wide temperature and density range. This necessitates the use of more advanced fluid models that impose additional computation overhead. In this study we compare two equation of state (EOS) mixture approximation approaches for cryogenic flows in rocket combustion chambers and present a computationally efficient implementation within a Reynolds Averaged Navier Stokes (RANS) context. The numerical study is validated with experimental results of a lab-scale rocket combustion chamber with optical access.
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Efficient Handling of Cryogenic Equation of State for the Simulation of Rocket Combustion Chambers
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10.1007/978-3-030-49626-5_2
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2020-01-01
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This chapter presents details of cryogenic Cryogenic machining of titanium Titanium alloys. It discusses different innovative methods used in literature for cryogenic machining of titanium alloys. A detailed methodology is presented to design a sustainable Sustainable cryogenic fluid delivery setup. It also covers economic aspects of cryogenic machining in comparison to dry machining. Finally, a sustainable liquid nitrogen delivery setup is designed and developed to perform cryogenic machining of Ti-6Al-4V. The design of this retrofittable cryogen delivery solution for a range of available machine tools shall provide a direct cost based impetus for improving machining of such materials, which at present does not exist for indigenous industry. For experimental analyses, three machining process parameters i.e. the cutting speed (v), feed (f) and depth of cut (d), and different machining environment i.e. dry and cryogenic are selected. Response variables selected for this study are surface roughness Surface roughness , resultant force and power consumption. Experiments are designed as per hybrid design of experiments (DoE) technique. Hybrid DoE is a combination of orthogonal array and full factorial methods. To investigate the results, each combination of process parameters are compared under dry and cryogenic machining. Analysis of variance technique (ANOVA) is used to reveal the effect of process parameters on response variables. The results show that better surface finish obtained under cryogenic machining in comparison to dry machining. Results of power consumption suggest suitability of cryogenic Cryogenic machining over dry machining at higher levels of process parameters.
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Titanium Machining Using Indigenously Developed Sustainable Cryogenic Machining Facility
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10.1007/978-3-030-18854-2_8
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2020-01-01
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Due to their many advantages, flexible structures are increasingly being used as guide and transmission elements in handling systems. Prismatic solid-state joints with a concentrated cross-sectional reduction are predominantly used as flexure pivots for both microscopic and macroscopic designs. A transfer of these geometries to applications in cryogenic working environments is not easily possible at temperatures below -130 °C due to the changed material properties. In this paper, the further development of swivel joints as cascaded solid state joints for such a cryogenic environment is illustrated by the targeted adaptation of certain joint parameters and dimensions. By means of a comprehensive FEM simulation, it can be shown how the influence of specific parameters affects movement accuracy, process forces and shape stability and to what extent these geometric parameters influence each other in their effect.
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Numerical simulation and statistical analysis of a cascaded flexure hinge for use in a cryogenic working environment
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10.1007/978-3-662-61755-7_8
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2020-01-01
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Absolute primary radiometric thermometry is a recently introduced term for an approach to measuring the thermodynamic temperature of a blackbody Blackbody using the accurate determination of the radiant flux Radiant flux that it emits in a known spectral band and known solid angle. The instrumental and metrological infrastructure for measuring thermodynamic temperature of high-temperature blackbodies are described. Four schemes of the filter radiometer calibration in terms of the spectral power, irradiance Irradiance , and radiance and corresponding sources of measurement uncertainties Uncertainty are discussed. Calibration facilities on the base of tunable lasers Tunable laser and monochromators Monochromator are described and compared. The state-of-the-art uncertainties Uncertainty in measuring temperature of the high-temperature blackbodies are discussed.
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Absolute Primary Radiometric Thermometry
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10.1007/978-3-030-57789-6_9
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2020-01-01
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The application of satellite technology in the Internet of Things (IOT) can just make up for the defects of the ground system for its wide coverage and anti-damage. More and more satellites will participate in IOT. Due to the environmental protection exhaust and high specific impulse of cryogenic propellants like liquid hydrogen and liquid oxygen, they will play an important role in satellite applications. Cryogenic liquid storage is difficult and self-pressurization phenomenon often occurs. Pressure rise prediction with high accurate is necessary when designing tank for storage. Numerical calculation of computational fluid dynamic model and experiments are always time and financial consuming. A theoretical thermal diffusion model is investigated in the paper by using a concentration parameter model in the vapor and a one-dimensional heat conduction model in the liquid. The validation of the predictive capability is conducted by comparing the predictions with experimental data. Favorable agreement is found for both the experimental cylindrical and oblate spheroidal tanks. The effect of fill level and tank size is also studied.
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Theoretical and Experimental Comparisons of the Self-pressurization in a Cryogenic Storage Tank for IOT Application
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10.1007/978-3-030-44751-9_25
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2020-01-01
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Transmission soft x-ray microscopy (SXM) is well suited to visualizing and quantifying mesoscale biology, that is to say structures ranging from the size of a typical molecular machine up to an intact cell. In SXM, the specimen is illuminated with “water window” soft x-rays (i.e., photons with energies in the range 284 eV to 543 eV). The degree to which the illumination is absorbed by a subcellular feature depends on its chemical composition. Carbon- and nitrogen-containing biomolecules strongly absorb the illumination, while water is relatively transparent. Similarities and differences in subcellular molecular content generate contrast in SXM images of the specimen without the use of stains. In this chapter, we discuss the basic concepts behind SXM and describe how 2D SXM data is used to calculate a 3D soft x-ray tomographic (SXT) reconstruction of the specimen. SXT offers significant advantages over other high-resolution cell imaging methods. A particular strength is the capacity to image intact, fully hydrated cells, including eukaryotes such as yeast or mammalian cells. In addition to stand-alone use, we will show that SXT data can be integrated into other imaging modalities to create a comprehensive view of the specimen. The combination of SXT with fluorescence data measured from the same specimen is particularly important, since this allows molecular localization data to be viewed directly in the context of the cell.
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Putting Molecules in the Picture: Using Correlated Light Microscopy and Soft X-Ray Tomography to Study Cells
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10.1007/978-3-030-23201-6_43
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2020-01-01
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Abstract Credible data on the actual characteristics of thin-film platinum temperature sensors with a nominal value of 1000 Ω in a wide temperature range of 3.8–370 K derived from long-term experimental studies of a large batch of 130 sensors are presented (most likely, for the first time). These characteristics are the temperature dependence of resistance, sensitivity, short-term and long-term stability, response to thermal cycling in the 293–77.3 K range, thermal resistance in liquid nitrogen and helium, measurement accuracy and interpolation polynomials, and gamma-radiation resistance. The calibration data are compared to the DIN EN 60751 standard and equivalent information for a pure platinum sensor. It is demonstrated that the actual parameters of sensors of the studied type are better than the datasheet ones: contrary to literature data, the measurement accuracy at cryogenic temperatures improves as the temperature decreases. Ways to increase the accuracy rating of these sensors are discussed. Data on their practical application in the XFEL superconducting accelerator project (Hamburg) and other projects are also provided.
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Application of Pt1000 C420 Thin-Film Temperature Sensors at Superconducting and Other Types of Facilities
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10.1134/S1547477120010124
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2020-01-01
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Cryopreservation is an age-old technology which was practised in different forms. It has evolved from preserving cells in snow to liquid nitrogen. As necessity is the mother of invention, the need for mankind invents new technologies. Cryopreservation is also such a technology which helped increasing the livestock production. It is a technology which made human sperm bank and stem cell storage possible. In this chapter, various historical developments of cryopreservation in all fields of life science with special emphasis on fisheries are discussed.
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Cryopreservation: History and Development
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10.1007/978-981-15-4025-7_6
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2020-01-01
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It is now approaching 50 years since the first reports were made on cryopreservation of mammalian embryos with successful recoveries and subsequent live births. These successes were the result of growing shared knowledge between the fields of reproductive biology and cryobiology. Once manipulation of human embryos became possible in infertility treatment, embryo cryopreservation was quickly taken up to enhance logistics and patient management within the clinical services. Now, embryo cryopreservation is seen as a crucial component to enhance overall success rates, whilst advances in cryobiology have brought forward new techniques such as vitrification. This chapter reviews the history of embryo cryopreservation, the basic scientific principles underpinning the technologies, and provides an example of how these are currently applied in a clinical practice.
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Cryopreservation of Human Embryos: Basic Principles and Current Considerations
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10.1007/978-981-15-2377-9_57
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2020-01-01
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Nowadays with growing pollution and contamination by hydrocarbon (petroleum) based cutting fluids, the scope for vegetable or synthetic biodegradable esters based eco-friendly cutting fluids is increasing. In this review work, the main focus is on sustainable Sustainable machining using advanced cutting fluid application techniques with eco-friendly cutting fluids. Understanding the functions and various types of cutting fluids are critically important to maximize its performance during any machining process. Also, cutting fluid application techniques are equally important to minimize the use of cutting fluids for the desired machining processes. This review article focuses on the conventional cutting fluids, function of cutting fluids, ecological aspects of conventional cutting fluids, eco-friendly cutting fluids, cutting fluid application techniques during machining and their performances in order to establish the research field further. An overview of the role of eco-friendly cutting fluids and cooling techniques are discussed and finally concluding remarks and possible scope of future work is presented.
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Role of Eco-friendly Cutting Fluids and Cooling Techniques in Machining
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10.1007/978-3-030-18854-2_7
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2020-01-01
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Adoption of sustainable machining techniques shall offer the local industry a cost-effective route to improve its environmental, economic and social footprint when it comes to machine difficult-to-cut materials. This experimental study investigates the behavior of sustainable cutting fluid approaches on active cutting energy (ACE), active energy consumed by machine tool (AECM) and energy efficiency (EE) for machining PMMCs (particulate metal matrix composites) of magnesium at different combinations of rotational speed and feed. Minimum Quantity Lubrication (MQL), cryogenic and CryoMQL machining are performed on in-house developed MQL and cryogenic experimental setups and the results obtained from them are compared with dry machining. The L_36 orthogonal array is employed to design the experiments. It is observed that cryogenic machining consumes comparatively lower ACE and AECM among the four cutting fluid approaches. It is found that dry machining provides comparatively lower EE among four cutting fluid approaches. From the main effects plot, it is observed that cryogenic assistance further improves the machining performance of the MQL technique and offers better EE. The results of Analysis of Variance (ANOVA) suggest that rotational speed, cutting fluid approach and feed are the significant parameters that affect the EE in descending order respectively.
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Energy Efficiency Analysis for Machining Magnesium Metal Matrix Composites Using In-House Developed Hybrid Machining Facilities
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10.1007/978-3-030-44248-4_13
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2020-01-01
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Third-generation synchrotron radiation (SR) X-rays have transformed structural biology research in the past decades with the advent of high-brilliance undulator X-ray beams. Combined with developments in microfocus beams, area detectors, and data analysis software, it is now possible to determine large complex structures from extremely small (microns in all directions) crystals, as exemplified by the structures of potassium channels, G-protein coupled receptors (GPCRs), ribosomes, and RNA polymerase complexes. The number of depositions in PDB (the Protein Data Bank) is already more than 100,000, the majority of which have been determined by X-rays. Almost all biology, biochemistry, and molecular biology textbooks now contain protein structures to explain their functions in the cell. Now, X-ray free-electron lasers (XFELs) promise to provide new opportunities in structural biology research. They produce X-ray beams with extraordinary properties: 9 to 10 orders of magnitude higher peak brilliance and 1000 times shorter pulse lengths, compared to existing synchrotron radiation beamlines around the world. Diffraction patterns can be recorded from micro and nanocrystals before radiation damage starts to destroy the samples. Using this “diffract-before-destroy” concept, a new area of XFEL biology has arisen, wherein biologically important questions are tackled beyond what is possible using traditional SR. Ultrashort XFEL pulses allow for frozen-in-time fluctuation X-ray scattering with a possibility of expanding isotropic solution scattering. New modes of XFEL pulses such as two-pulse/two-color are being developed for pump-probe femtosecond time-resolved experiments and phasing. Additionally, hybrid methods are increasingly used for challenging biological questions, in which SR and XFEL methods are combined with other methods such as cryo-electron microscopy, NMR, DEER, and optical and atomic force microscopes. Taken together, SR and XFELs provide a portfolio of structural biology tools which continue to enable cutting edge structural biology research of complex molecular machineries.
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Structural Biology Applications of Synchrotron Radiation and X-Ray Free-Electron Lasers
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10.1007/978-3-030-23201-6_44
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2020-01-01
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Cryogenic CO_2 capture technology is one of the emerging technologies used for natural gas purification. Thermodynamic phase study of the natural gas has a significant effect on the cryogenic CO_2 removal from natural gas. The present work describes the impact of composition on CO_2 freeze-out and critical locus of the binary CO_2–CH_4 mixtures with different CO_2 content. Critical locus and CO_2 freeze-out were modelled for nine binary CO_2–CH_4 mixtures and were correlated with the composition of the binary mixtures. Aspen HYSYS version 8.0 with the Peng Robinson equation of state and Eureka modelling tool were used in the present research work. It was found that the predicted models can precisely calculate the CO_2 freeze-out point and the critical locus of the mixtures. By comparing the calculated data with the reported experimental data, an excellent agreement was found. R-squared value for the models was 0.99, which shows the reliability of the models. The effect of composition on three-phase loci of the binary and multicomponent mixtures of CO_2 with light H.C is recommended for future research.
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The Effect of Composition on CO_2 Freeze-Out and Critical Locus of Binary CO_2–CH_4 Mixture
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10.1007/978-981-15-5753-8_1
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2020-01-01
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The effect of heat treatment and deep cryogenic treatment on microstructural evolution of low carbon martensitic bearing steel was investigated. The experimental results showed that the lath martensite was obtained by quenching and a few twins as substructures formed in some martensitic laths. The rudiment of sub-interfaces of martensitic lath was formed in the high-density dislocation regions after deep cryogenic treatment; meanwhile, the number of twins increased, especially in the high-density dislocation regions. This phenomenon is due to the increase in internal stress caused by cryogenic treatment. After tempering, the rudiment of sub-interface further evolved into the martensitic lath boundary, and thus the original martensitic laths were refined. The twins formed by cryogenic treatment did not disappear after tempering. In addition, small quantities of annealing twins formed in tempering process. Martensitic laths morphology and substructures in different stages of the heat and deep cryogenic treatment were observed by transmission electron microscopy.
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Effect of deep cryogenic treatment on martensitic lath refinement and nano-twins formation of low carbon bearing steel
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10.1007/s42243-019-00356-1
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2020-01-01
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Martensitic grade SS410 is used extensively for manufacturing of turbine blades and other hydro-machinery components. During working of such components, due to poor mechanical properties of the material, the components lose its functionality and life of such components decreases. In this regard, the improvement in the material properties is essential, to enhance the life of such components. For improving the mechanical and metallurgical properties of the material, deep cryogenic treatment (DCT) can be effectively used. In this research work, DCT followed by tempering at two temperatures 350 and 250 °C has been performed on SS410. The SS410 specimens with and without DCT were tested for tensile strength, toughness, and micro-hardness. It has been observed that DCT followed by post-tempering at 250 °C has shown better results in terms of ultimate tensile strength (UTS) and micro-hardness as compared to its counterparts. This may correspond to the conversion of retained austenite to martensite and formation of fine secondary carbides.
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Effect of Cryogenic Treatment on Mechanical and Metallurgical Properties of SS410
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10.1007/978-981-15-4619-8_17
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2020-01-01
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Surface integrity of machined subsurface is an important aspect in any machining process especially in high accuracy demand industries like aerospace. As is known, Inconel 718 is a difficult to machine material and in most cases, Inconel 718 will be resulting an excessive heat generated at the cutting zone which can causes rapid tool wear, damage on machined surface and microstructural defects. Hence, various cooling methods have been made to address these problems and improve the quality of machined surface. In this study, a cryogenic cooling technique using nitrogen liquids (LN_2) was developed for cooling the tool-chip interface during milling Inconel 718. The goal of this paper is to present a comparison study on surface roughness, machined surface microhardness and subsurface microstructure changes between cryogenic cooling and dry techniques. The experiments conducted using a physical vapor deposition (PVD) coated with TiAlN/AlCrN ball nose tungsten carbide for a range of cutting speeds between 140–160 m/min, 0.15–0.20 mm/tooth for a feed rate, and 0.2–0.4 mm for radial depth of cut. The results show that the cryogenic cooling technique is more effective than dry cutting for improving surface roughness and lessening deformation of microstructure changes underneath the machined surface. However, machining in dry technique has produced a high microhardness for machined surface compared to cryogenic cooling technique. Overall, the utilization of the cryogenic technique has improved the surface roughness to a maximum of 88% and reduced the plastic deformation layer, while dry machining can improve the surface microhardness up to 5%.
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Enhancement of Surface Integrity in Cryogenic High Speed Ball Nose End Milling Process of Inconel 718
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10.1007/978-981-15-0950-6_78
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2020-01-01
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It is always interesting and exciting to get some information on the history of an activity. A survey starting from liquefaction of the “permanent” gases up to the present state of cryogenic refrigeration is described.
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The Saga of Cryogenic Refrigeration
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10.1007/978-3-030-51677-2_16
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2020-01-01
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Bangladesh is enriched with aquatic biodiversity and ranked third in Asia after China and India. It has highly potential fisheries resources comprising 260 freshwater fish, 475 marine fish, 24 freshwater prawn, and 36 marine shrimp species. The country produced 4.134 million metric tons fish in the year 2017, in which open water capture fishery contributed 28.14% and aquaculture contributed 56.44%. Presently, Bangladesh ranked fifth in aquaculture production and third in open water capture fisheries in the world. Earlier, the lion share of the production came from open water capture fisheries, but the production has been reduced over the years due to environmental and human-created problems. As a result, natural recruitment of many fish species has been hampered and they became threatened. According to IUCN Bangladesh (2015), among the 260 fresh water fish species, 9 have been categorized as critically endangered, 30 as endangered, and 25 as vulnerable. Aquaculture production of the country is being increased day by day due to availability of seeds produced through hypophysation in the private and government hatcheries, but the quality of seeds has been deteriorated due to some genetics causes such as inbreeding, interspecific hybridization, and negative selection. Therefore, it is urgent to protect the endangered fish as well as to improve the quality of seeds of commercially important fish species. This can be done by applying cryopreservation techniques associated with genetic improvement program. Considering the potential of fish cryopreservation, research on sperm cryopreservation began in the Department of Fisheries Biology and Genetics, Bangladesh Agricultural University in 2002, and protocols have been developed for a number of fish species such as Indian major carps, exotic carps, catfishes, indigenous endangered fish species, barb, and tilapia. Breeding of Indian major carps using cryopreserved sperm in private hatcheries demonstrated excellent performance of cryopreserved sperm-originated seeds and broods that urged to establish cryogenic sperm bank of commercially important fish as well as endangered fish species in Bangladesh.
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Potential of Fish Gamete Cryopreservation in Conservation Programs in Bangladesh
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10.1007/978-981-15-4025-7_14
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2020-01-01
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Thick section of cold-rolled austenite stainless steel Steel AISI 316 is widely used in heat exchangers, jet engines, furnace parts, exhaust manifolds, fast breeder test rector, etc., because of its high strength, corrosion Corrosion , and pitting Pitting resistance properties at high working temperature 400–550 °C approximately. Electron beam welding Electron beam welding is considered as highly efficient welding process in order to achieve high-quality welds with low heat-affected zone. In this paper, single-pass narrow gap square butt welding of 18-mm-thick plates using electron beam welding Electron beam welding at constant accelerating voltage 150 kV, beam current 90 mA, welding travel speed 600 mm/min, and beam oscillation in circular pattern was investigated. The impact toughness and metallurgical properties Metallurgical properties in as-welded condition and after imparting post-weld thermal aging (PWTA) at 750 °C for 24 h were also investigated in this piece of work. The full penetration had been achieved in single pass by optimizing the relationship between welding parameters (beam accelerating voltage, beam current, welding travel speed, and beam oscillation). The results showed that welding of plates without filler metal leads to defect-free welds. The average impact toughness conducted by Charpy impact test at cryogenic temperature (−40 °C) in as-welded samples was recorded as 284 J, and after aged at 750 °C for 24 h it reduced to 180 J.
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Effect of Thermal Aging on Impact Toughness of Electron Beam-Welded AISI 316 Stainless Steel
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10.1007/978-3-030-36628-5_16
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2020-01-01
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Liquid based AM processes are varied: in one extreme very big parts can be made by photopolymerization and in the other extreme thinner lines are deposited for electronics applications; besides, this is the liquid which has started non-layer based AM processes. This chapter has brought all processes together, though it deals only with layer based processes. While photopolymer bed and liquid deposition process are briefly mentioned, water based process and slurry based process are dealt with in somewhat detail. This chapter has reasoned why the name stereolithography is illogical, and thus photopolymer bed process described in Chap. 2 can instead be a better name. Four-dimensional printing utilizes liquid based AM processes and therefore its relation with liquid based AM processes is mentioned.
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Liquid Based Additive Layer Manufacturing
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10.1007/978-3-030-45089-2_8
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2020-01-01
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Electrical discharge machining (EDM), based on thermal erosion principle, is used to machine materials in the area of aerospace, surface texturing, die, and mold manufacturing. In this work, an attempt is made to use oil extracted from vegetable as dielectric fluid and to carry out optimization study of EDM using Taguchi-based hybrid optimization technique. Taguchi optimization method is a statistical approach to determine optimum process parameters, but it is appropriate for solving single-objective problem. Most of the manufacturing industries problems are involved with multiple objectives. Hence, Taguchi method must unite with some other techniques such as gray relational approach, desirability function, and utility concept to multiple objectives. Taguchi method is combined with VlseKriterijumska Optimizacija I Kompromisno Resenje in Serbian (VIKOR) for solving multiple objectives simultaneously. The performance of commercial dielectric fluid (kerosene) is compared with two different types of vegetable oils such as Jatropha oil and cottonseed oil. Copper is selected as electrode material which is cryogenically treated and tempered. The result showed that the proposed approach has easy computational steps for solving multiple objectives simultaneously and the same can be applicable to other machining process parameter optimizations.
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Optimization of Process Parameters Using Hybrid Taguchi and VIKOR Method in Electrical Discharge Machining Process
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10.1007/978-981-13-8196-6_46
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2020-01-01
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The paper gives examples of determining the causes of roadbed deformations and its strengthening on the Baikal-Amur Mainline and Amur-Yakutsk Mainline, the Berkakit–Tommot section. The main principles determining the construction in permafrost areas are, on the one hand, low capital and running costs of an immediate normalization of engineering and geological processes (those of the frozen ground first of all) in the bases of natural and man-made systems (earth structures—roads), and on the other hand, an adherence to a balanced thermoregulation of developed areas within their landscapes. The goals of all conservation and anti-deformation measures that provide a stability of natural and man-made systems are achieving high strength characteristics of the roadbed soils and its subgrade in shortest time and providing the longest period of their service.
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Complex Solutions for Providing Roadbed Stability on Permafrost
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10.1007/978-981-15-0450-1_24
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2020-01-01
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Abstract Numerical simulation of 2D Cryogenic Pulsating Heat Pipe (CPHP) is carried out with near critical diameter. Liquid nitrogen is used as working fluid for targeting cryogenic applications in the range from 77 to 123 K. The volume of fluid (VOF) model is considered for two phase simulations. The evaporator and condenser section are kept at constant wall temperature condition while adiabatic section is considered insulated. The evaporator temperature varied from 85 to 110 K and condenser section kept at 75 K. The filling ratio (FR) of working fluid is varied as 50, 60 and 70%. CPHP model is first tested with on ground gravity condition of 9.81 m/s^2. It is then tested with low gravity conditions (0.981 m/s^2) and milli-gravity condition (0.01 m/s^2). In low gravity condition, surface tension force is observed more dominant than body force which significantly altered the performance of a CPHP. In comparisons with ground level condition, more stable flow patterns are observed which led to the improved heat transfer performance of a CPHP in case of low gravity.
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CFD Analysis of Cryogenic Pulsating Heat Pipe with Near Critical Diameter under Varying Gravity Conditions
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10.1134/S0040579520010212
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2020-01-01
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The paper covers the results of phenomena and process researches that influence deformations in soil bases in the annual cycle. The target research focuses on deformations in an embankment under operation in severe natural climatic, engineering and geological conditions. The causes of a road exploitation in permafrost areas with cryogenic deformations are presented. It is necessary to reduce the length of sections under the slow order that has been introduced due to unpredictable deformations in the embankment, while the sections are located in complex natural, climatic, geological and engineering conditions. In addition, it is necessary to provide a planned strengthening of the embankment, thus preventing appearance of deformations, and carry out a reconstruction of the embankment on the sections expecting an increasing volume of coal. A cause-effect analysis of processes and phenomena in soils fosters justification of designs and their better selection for improving mechanical strength characteristics that accord with natural restoring processes in soils (drainage and strengthening). A rational justification of the roadbed strengthening and a testing introduction are mandatory requirements for the roadbed design that provides the technical system bearing capacity with developed and patented technical solutions.
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Soil Research for Strengthening Railroad Bed Design in Cold Regions of Far East
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10.1007/978-3-030-37919-3_6
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2020-01-01
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Glycosaminoglycans (GAGs) are a physio- and pharmacologically highly relevant class of complex saccharides, possessing a linear sequence and strongly acidic character. Their repetitive linear core makes them seem structurally simple at first glance, yet differences in sulfation and epimerization lead to an enormous structural diversity with only a few GAGs having been successfully characterized to date. Recent infrared action spectroscopic experiments on sulfated mono- and disaccharide ions show great promise. Here, we assess the potential of two types of gas-phase action spectroscopy approaches in the range from 1000 to 1800 cm^−1 for the structural analysis of complex GAG oligosaccharides. Synthetic tetra- and pentasaccharides were chosen as model compounds for this benchmark study. Utilizing infrared multiple photon dissociation action spectroscopy at room temperature, diagnostic bands are largely unresolved. In contrast, cryogenic infrared action spectroscopy of ions trapped in helium nanodroplets yields resolved infrared spectra with diagnostic features for monosaccharide composition and sulfation pattern. The analysis of GAGs could therefore significantly benefit from expanding the conventional MS-based toolkit with gas-phase cryogenic IR spectroscopy. Graphical abstract
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IR action spectroscopy of glycosaminoglycan oligosaccharides
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10.1007/s00216-019-02327-7
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2019-12-19
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Temperature variation is one of the primary factors influencing the physical properties of rocks. Currently, research on improvement of energy efficiency in comminution of rocks using various pre-treatment methods is an important topic, worldwide. So, a proper pre-treatment for rocks reduces the energy required for comminution. In this paper, experimental data on strength properties of granite and sandstone using two different pre-treatments i.e., individual microwave and combined microwave/liquid nitrogen quenching are presented. The samples are treated with varying time duration of microwave and quenching. The obtained results indicate that pre-treatments in rocks show a decreasing trend in strength values of both the rock samples. Granite samples show a 54% drop in ultimate tensile strength and a 26% drop in ultimate compressive strength for individual pre-treatment, whereas a decrease of 67% in ultimate tensile strength and 33% in ultimate compressive strength are also observed for combined pre-treated samples. Similarly, sandstone shows the same decreasing trend in strength properties for the pre-treated samples. Scanning electron microscope analyses of untreated and treated samples are carried out to understand the fracture morphology of both the rocks.
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Influence of individual and combined pre-treatment on the strength properties of granite and sandstone
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10.1007/s12517-019-5009-5
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2019-12-01
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The cryogenic machining and cryogenic treatment have already emerged as the sustainable manufacturing process of the future generation. The cryogenic treatment improves the cutting tool life, but the high cutting temperature developed during high-speed machining reduces the effect of cryogenic treatment of cutting tool. This study investigates the possible improvements in cutting tool life by combining cryogenic cooling and cryogenic treatment. The authors believe that these two techniques can replace conventional machining approaches using dry and wet machining conditions using coated carbide tools. The tungsten carbide-cobalt inserts are cryogenically treated (CT) at a soaking temperature of − 195.8 °C for a period of 24 h and are used to evaluate milling performance under dry, wet, and cryogenic cutting environments. The machining experiments are conducted on maraging steel MDN 250 using one factor at a time approach by varying spindle speed and keeping feed rate and depth of cut as constant. The cutting force, surface roughness, tool wear, and subsurface microhardness are some of the machining responses evaluated and compared with an untreated cutting tool (UT). The tool life improved up to 24% during cryogenic machining using CT tools at a spindle speed of 270 rpm.
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Experimental investigation of cryogenic end milling on maraging steel using cryogenically treated tungsten carbide-cobalt inserts
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10.1007/s00170-019-04387-6
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2019-12-01
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An urgent issue in research of inertial confinement fusion (ICF) is the development of the scientific, engineering, and technological base to settle the problem of quality protection of the fuel layer during the high repetition rate delivery of a cryogenic fuel target (CFT) to the focus of a high-power laser facility or ICF reactor. A concept of the multilevel system of CFT protection developed at the Lebedev Physical Institute of the Russian Academy of Sciences is discussed. The concept includes possible ways of integration of the latest developments in the area of formation of the stable ultrafine fuel structure and also the application of external methods of CFT protection such as the (cryogenic and/or metallic) CFT external coatings, the profiling of a target nest inside the sabot (CFT carrier), and the noncontact CFT delivery using a hybrid accelerator based on the effect of quantum levitation of high-temperature superconductors in a magnetic field. The results obtained during the theoretical and experimental simulation made it possible to transfer from the stage of conceptualization to the stage of engineering implementation of the problem.
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Multilevel System for Protecting the Cryogenic Target during Its Delivery to the Focus of High-Power Laser Facility at High Repetition Rate
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10.1134/S1063778819070019
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2019-12-01
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In the PANDA experiment of the FAIR project, it is proposed to use internal targets based on the hydrogen isotopes that provide a monodisperse regime of flow generation of solid spherical pellets with the diameter from 15–40 µm with the frequency from several tens of to several hundred kilohertz. The process for generating the pellets in such facilities includes the cooling, liquefying, and disintegration into drops of the liquid hydrogen jet directed vertically downwards; freezing of the jet when expiring with acceleration into vacuum; and its transport through the vacuum path into the region of interaction with the antiproton beam. For the effective control of the systems of the setup and for the adjustment of generation of pellets, an automatization and control system is developed combining the devices for measurement and control of pellet parameters (temperature, pressure, hydrogen flow, and piezoelectric generator frequency) and the optical diagnostics in a unified computational network. For data exchange between the devices, the TCP/IP Sockets and Modbus TCP protocols are used.
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Data Acquisition and Diagnostic System for Prototype of PANDA Pellet Target
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10.1134/S1063778819120135
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2019-12-01
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Abstract This article describes an experimental facility, which simulates the natural operating conditions of radiative coolers used for cooling photo-detectors of electronic optical equipment of spacecraft. The composition and main properties of the facility and the specific features of thermal vacuum tests at cryogenic temperatures are considered. Results of thermal vacuum tests of the radiative cooler for MSY-GS device used onboard a meteorological spacecraft are provided. The results are in good agreement with in-flight data.
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Simulating the Operational Conditions of Radiative Coolers for Photo-Detectors of Optoelectronic Equipment in Ground Thermal Vacuum Tests
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10.1134/S0038094619070116
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2019-12-01
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Cryogenic machining is an environmentally friendly process; liquid nitrogen (LN2) is sprayed onto cutting tool to reduce cutting temperature, increasing tool life. Cutting temperature and force were numerically predicted during cryogenic assisted milling with an internal coolant-assisted tool holder (internal cryogenic milling) for Ti-6Al-4V alloy. The influence of LN2 on the material temperature throughout the machining was estimated; a numerical model to simulate the initial temperature of work material was discussed by consideration of LN2 injective mechanism. A modified Johnson-Cook model including the cryogenic temperature range was adopted to model material plasticity. The predictive models were validated based on side-milling test. The predicted values captured the trend of experimental result; the minimum and maximum temperature errors were 0.1% and 8.6%, and those for the cutting force were 0.2% and 34.4%. Moreover, comprehensive experimental studies for the cutting temperature, cutting force, chip morphology, and chip composition were performed to understand the effect of cryogenic cooling condition. In internal cryogenic milling, the cutting temperature and force tended to be lower than dry machining. Based on the morphological analysis of the generated chip, the coefficient of sliding friction at tool-chip interface under the internal cooling was reduced by 21.4% as compared to the dry condition.
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Numerical and experimental study of end-milling process of titanium alloy with a cryogenic internal coolant supply
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10.1007/s00170-019-04425-3
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2019-11-15
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A helium cryogenic system is designed by the Institute of Modern Physics, Chinese Academy of Sciences, to supply different cooling powers to the cryomodules of ion-Linac (iLinac) accelerator, which serves as the injector of the High Intensity Heavy-Ion Accelerator Facility project. The iLinac is a superconducting heavy-ion accelerator approximately 100 m long and contains 13 cryomodules cooled by superfluid helium. This article describes the cryogenic system design of the iLinac accelerator. The requirements of the cryogenic system, such as cooling mode, refrigeration temperature, operating pressure and pressure stability, are introduced and described in detail. In addition, heat loads from different sources are analyzed and calculated quantitatively. An equivalent cooling capacity of 10 kW at 4.5 K was determined for the cryogenic system according to the total heat load. Furthermore, a system process design was conducted and analyzed in detail. Further, the system layout and the main equipment are presented.
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Cryogenic system design for HIAF iLinac
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10.1007/s41365-019-0700-5
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2019-11-15
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The infrared focal plane array (IRFPA) is gradually becoming more systematic. In order to enhance the signal processing capabilities, analog-to-digital converters (ADC) integrated into the readout integrated circuit (ROIC) is an important development trend. However, the cryogenic effects of MOSFET devices will affect the conversion accuracy of the ADC at 77 K. In this paper, the main parameters of MOSFET are extracted at 77 K in 0.18 μm CMOS process, and a cryogenic model is established. Based on this, a digital ROIC is designed, which integrates a 12-bit single-slope integral ADC in pixel unit. By applying continuous integral ramp generator and mixed-voltage comparator, a high-linearity and low-power consumption single-slope ADC is realized for the cooled readout circuit. The measured dynamic effective number of bits of the ADC at 77 K is 10.92 bits, the static no-missing code resolution reaches 11.99 bits, the maximum differential nonlinear |DNL| < 1LSB and maximum integral nonlinear |INL| < 1LSB. This paper realizes the design of a digital ROIC for IRFPA and improves the simulation accuracy at 77 K.
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Design of a readout circuit incorporating a 12-bit analog-to-digital converter for cooled infrared focal plane array
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10.1007/s11082-019-2084-5
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2019-11-01
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The geophysical investigations are carried out at the Kangalass open pit coal mine using the round penetrating radar and electrical tomography. The main frost effects in rock mass and in water retaining dam are described. The investigation procedure is developed, and the wave fields are characterized. The GPR surveys aimed to reveal water invasion zones in a rock block to be blasted and to trace dynamics of a seasonal thawing layer are presented. The integrated analysis of GPR and electrotomography data is performed to determine adverse freeze-and-thaw processes at the dam bottom. Applicability of GPR in prediction of unfavorable freeze-and-thaw activities is demonstrated.
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Geocryological Analysis of Rocks to Predict Adverse Freeze-and-Thaw Effects
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10.1134/S1062739119066417
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2019-11-01
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The effect of cryogenic treatment on the microstructure and mechanical properties of CoCrFeMnNi and CoCrFeMnNi(NbC) high-entropy alloys was investigated during annealing. The heat-treated samples were characterized by optical microscopy, scanning electron microscopy–wavelength-dispersive x-ray spectroscopy, x-ray diffraction technique, differential scanning calorimetry, Vickers hardness testing and tensile testing. The results showed a single-phase FCC crystal structure matrix in both alloys during cryogenic treatment and annealing. Cryogenic treatment altered the recrystallization behavior of CoCrFeMnNi high-entropy alloy, while it did not influence the recrystallization of CoCrFeMnNi(NbC) high-entropy alloy. It was also found that cryogenic treatment changed the precipitation behavior of CoCrFeMnNi(NbC) high-entropy alloy during annealing. In both studied high-entropy alloys, the mechanical testing indicated that the cryogenic treatment can effectively reduce the yield strength of cold-rolled samples after annealing. This was primarily attributed to the effect of cryogenic treatment in enhancing crystalline defects annihilation. Furthermore, the cryogenic treatment increased the ultimate tensile strength of CoCrFeMnNi(NbC). A lager plastic deformation and precipitates were considered as the main reasons for the higher ultimate tensile strength.
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Cryogenic Treatment of CoCrFeMnNi(NbC) High-Entropy Alloys
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10.1007/s11665-019-04439-8
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2019-11-01
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The application of components often depends to a large extent on the properties of the surface layer. A novel process chain for the production of components with a hardened surface layer from metastable austenitic steel was presented. The investigated metastable austenitic AISI 347 steel was cold-drawn in solution annealed condition at cryogenic temperatures for pre-hardening, followed by post-hardening via cryogenic turning. The increase in hardness in both processes was due to strain hardening and deformation-induced phase transformation from γ-austenite to α′-martensite. Cryogenic turning experiments were carried out with solution annealed AISI 347 steel as well as with solution annealed and subsequently cold-drawn AISI 347 steel. The thermomechanical load of the workpiece surface layer during the turning process as well as the resulting surface morphology was characterized. The forces and temperatures were higher in turning the cold-drawn AISI 347 steel than turning the solution annealed AISI 347 steel. After cryogenic turning of the solution annealed material, deformation-induced phase transformation and a significant increase in hardness were detected in the near-surface layer. In contrast, no additional phase transformation was observed after cryogenic turning of the cold-drawn AISI 347 steel. The maximum hardness in the surface layer was similar, whereas the hardness in the core of the cold-drawn AISI 347 steel was higher compared to that in the solution annealed AISI 347 steel.
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Combination of cold drawing and cryogenic turning for modifying surface morphology of metastable austenitic AISI 347 steel
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10.1007/s42243-019-00306-x
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2019-10-01
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The structure and physical properties of polyimide matrix composites lead to serious tool wear. And the cutting force is the obvious effect on machining efficiency in dry and cryogenic milling process. A predicted model was fabricated considering cutting temperature. The cryogenic cooling milling method was executed for a series of processing experiments. At the same time, the machining surface morphology, roughness, and cutting force were measured and analyzed compared with dry cutting. Meanwhile, the tool wear regular and mechanism were discussed. The result shows that the cutting force model of composite materials is improved based on cryogenic cutting performance. The friction coefficient of tool/workpiece on contact surface is greatly affected by the cutting heat, and the friction coefficient is reduced in the cutting force model. At the same time, the mechanical properties such as modulus in the model are increased with the decrease of temperature, and it leads to the increase cryogenic milling force. In the milling test, the increase of tensile and compressive strength of composite material is caused by cryogenic cooling. The change leads to the increase of material brittleness with bigger cutting force. Meanwhile, the breaking chip is changed with the improvement of processing quality. Similarly, the better cutting parameter is v _c = 100/min, a _p = 1.5 mm, and = 40°. In cryogenics, because of the poor thermal conductivity of composite material, part of the fiber material is still not effectively cryogenic treated with the increase in cutting depth; it cannot be brittle cutting for bigger cutting depth material.
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Milling force of quartz fiber–reinforced polyimide composite based on cryogenic cooling
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10.1007/s00170-019-04050-0
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2019-10-01
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Ti-6Al-4V with its ELI variant is a potential biomaterial for structural implants. However, its poor resistance to plastic shearing results in poor tribological properties that hinders its widespread use in biomedical implants. Cryogenic treatment being an established technique for improving wear resistance and other mechanical properties of ferrous materials is applied on Ti-6Al-4V ELI alloy. To ensure comprehensive investigations, the widely studied microstructures of Ti-6Al-4V ELI, i.e., lamellar, martensite, two variants of bimodal and mill annealed are considered in this work. Deep cryogenic treatment at the soaking temperature (− 196 °C) for 24 h soaking time followed by tempering has been applied. The impact of cryogenic treatment has been assessed in terms of changes in the mechanical behavior including wear resistance, hardness, tensile properties and impact strength. The alterations in mechanical behavior due to cryogenic treatment are correlated with microstructure evolution. Cryogenic treatment has caused significant improvement in mechanical behavior of Ti-6Al-4V ELI alloy.
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Impact of Cryogenic Treatment on Mechanical Behavior and Microstructure of Ti-6Al-4V ELI Biomaterial
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10.1007/s11665-019-04338-y
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2019-10-01
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Additive manufacturing (AM) processes are rapidly growing, thanks to the chance they offer for the component customization in terms of both in-service performances and geometrical features. Nevertheless, AM products still need finishing operations to obtain suitable surface finish, which may introduce machinability issues on the basis of the different mechanical and microstructural characteristics AM metal alloys have compared with the wrought ones. This work presents the pivotal topic of surface integrity evaluation of electron beam melted (EBM) Ti6Al4V titanium alloy after finishing turning operations carried out under dry, flood, and cryogenic cooling conditions at different feed rates. For the sake of comparison, the same machining trials were conducted on the wrought alloy. The machining-induced effects were broadly studied in terms of microstructural and mechanical features, residual stress nature, surface topography, and defects. Moreover, the corrosion behavior of the machined surfaces in simulated physiological conditions was also tested, proving that the combination of the particular microstructure of the EBM Ti6Al4V alloy with cryogenic machining allowed for significant improvement of the corrosion performances.
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Improving surface integrity and corrosion resistance of additive manufactured Ti6Al4V alloy by cryogenic machining
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10.1007/s00170-019-04180-5
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2019-10-01
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Nickel alloys such as Inconel 718 have been widely used in the aerospace, oil and gas, and chemical industries, since they have excellent properties that combine high creep resistance and high mechanical strength, fatigue and corrosion. However, these properties make these alloys extremely difficult to machine, due to a high level of heat generation during material removal, causing rapid wear of cutting tools and a detrimental effect on the surface integrity, reducing the fatigue life of the machined component and lowering the productivity. Looking at the literature, it seemed that there is an opportunity to study the surface integrity of Inconel 718, turned under cryogenic conditions at cutting speeds of 250, 275 and 300 m/min. For these reasons, this work aims to evaluate the influence of the cutting parameters on the surface integrity of Inconel 718 turned under cryogenic conditions using liquid nitrogen (LN2) at high cutting speeds. A whisker-reinforced ceramic tool was used in order to provide wear and shock resistance at high cutting speeds; these are factors that are associated with surface integrity in terms of roughness Ra, residual stresses, microhardness and cutting forces. A central composite design was chosen as factorial planning for the independent variables including cutting speed, feed rate and depth of cut when carrying out the experiments. Cryogenic cooling resulted in an average cutting force of 267 N, where the penetration force was higher. The roughness Ra was 0.52 μm and was influenced by the feed rate and depth of cut. The highest tensile residual stresses in the circumferential direction with LN2 and under dry conditions were 1394 MPa and 1237 MPa, respectively and were influenced by the depth of cut. Small changes in microhardness occurred at a depth of 0.3 mm from beneath machine surface and the presence of a white layer was not observed. Although tensile residual stresses were slightly higher when using LN2 compared to dry machining on the surface, the use of LN2 caused higher compressive residual stresses at the subsurface, which can improve the fatigue life of machined components at high cutting speeds. The results showed that lower cutting parameters tend to give the best results in terms of the cutting force and surface integrity.
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Surface integrity of INCONEL 718 turned under cryogenic conditions at high cutting speeds
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10.1007/s00170-019-03946-1
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2019-10-01
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Abstract— The paper is targeted at positioning the cryogenic soils in the recent classification system of Russian soils. An on-line discussion and recent publications demonstrated significant differences in conceptual approaches to cryogenic soils, as well as their unaccounted diversity in the permafrost zone and their dynamics in time (e.g., during the thawing period) that create problems for their classification. In particular, the results depend on the observation time. Diagnostic properties of cryogenic horizon and the depth of the active layer were in the center of the discussion. Possible changes in the list of soil types and subtypes are proposed for the next approximation of the Russian soil classification system. The Cryozem order is proposed for the soils with the cryogenic diagnostic horizon (CR) and the maximum active layer depth of 1 m and less. Soils with other diagnostic horizons and with the active layer depth of more than 1 m should be accounted as permafrost-affected soils within the other orders of the soil classification system. Authors invite colleagues to further discussion with the aim to establish standard classification criteria for cryogenic soils.
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Problems of the Cryogenic Soils’ Diagnostics in the Recent Russian Soil Classification System
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10.1134/S1064229319080106
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2019-09-16
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We describe an instrumental configuration for the structural characterization of fragment ions generated by collisional dissociation of peptide ions in the typical MS^2 scheme widely used for peptide sequencing. Structures are determined by comparing the vibrational band patterns displayed by cryogenically cooled ions with calculated spectra for candidate structural isomers. These spectra were obtained in a linear action mode by photodissociation of weakly bound D_2 molecules. This is accomplished by interfacing a Thermo Fisher Scientific Orbitrap Velos Pro to a cryogenic, triple focusing time-of-flight photofragmentation mass spectrometer (the Yale TOF spectrometer). The interface involves replacement of the Orbitrap’s higher-energy collisional dissociation cell with a voltage-gated aperture that maintains the commercial instrument’s standard capabilities while enabling bidirectional transfer of ions between the high-resolution FT analyzer and external ion sources. The performance of this hybrid instrument is demonstrated by its application to the a_1, y_1 and z_1 fragment ions generated by CID of a prototypical dipeptide precursor, protonated L-phenylalanyl-L-tyrosine (H^+-Phe-Tyr-OH or FY-H^+). The structure of the unusual z_1 ion, nominally formed after NH_3 is ejected from the protonated tyrosine (y_1) product, is identified as the cyclopropane-based product is tentatively identified as a cyclopropane-based product.
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Integration of High-Resolution Mass Spectrometry with Cryogenic Ion Vibrational Spectroscopy
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10.1007/s13361-019-02238-y
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2019-09-09
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17-4 precipitation-hardenable (PH) stainless steel is one of the widely used materials in various applications of engineering practices owing to their excellent corrosion resistance and high strength. The components such as automotive body, aerospace compressor blades, turbine blades and molds demand higher load carrying capacity and improved fatigue strength, which is possible to achieve by surface severe plastic deformation. Diamond burnishing process is an appropriate technique to produce such components which improves the surface integrity characteristics of the material. This article presents a comprehensive examination of the surface integrity of cryogenic diamond burnished 17-4 PH stainless steel using a novel diamond burnishing tool. The impact of diamond burnishing control factors on subsurface microhardness, surface roughness, surface hardness, surface topography, residual stress and surface morphology has been analyzed. The optimal control factor setting ensures the least surface roughness of 0.03 µm by the application of one factor at a time approach. Cryogenic diamond burnished surface achieves the exceptional surface finish and the surface hardness in tool-tip of 8 mm and 6 mm, respectively. The maximum surface hardness of 413 HV was attained using 6-mm tool-tip diameter. The subsurface microhardness improvement of 2% and 4% has been observed while using a tool-tip diameter of 6 mm in contrast to 8 mm and 10 mm. Compressive residual stresses have been generated at the top surface layer of the specimen. The attained experimental results prove that cryogenic diamond burnishing can be successfully applied to 17-4 PH stainless steel to enhance its surface integrity characteristics.
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Enhancement of surface integrity by cryogenic diamond burnishing toward the improved functional performance of the components
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10.1007/s40430-019-1918-1
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2019-09-06
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In the present research, the effects of Nickel (Ni) and Chromium (Cr) on cryogenic impact toughness (CIT) of low-carbon bainite/martensite multiphase steels [processed by two different cooling processes: isothermal transformation process (ITP) and continuous cooling process (CCP)] were investigated. It was found that due to the formation of carbides during isothermal treatment, the addition of Ni and Cr yielded no significant improvements in CIT. However, during CCP treatment, the addition of Ni manifested a considerable enhancement in CIT, whereas the addition of both Ni and Cr caused a decrease in CIT. Further, after ITP treatment, the microstructure of all steels consisted of bainite and martenite, while Ni + Cr steel contained the largest amount of bainite. The microstructures of the CCP-treated steels mainly also consisted of bainite and martensite, but no retained austenite and carbides were observed, thus resulting in a superior CIT.
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Effects of Ni and Cr on Cryogenic Impact Toughness of Bainite/Martensite Multiphase Steels
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10.1007/s12540-019-00262-x
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2019-09-01
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The scarcity of fossil fuels and the worldwide pollution have led the scientific community to seek renewable energy alternatives. In particular, biogas has become a potential alternative fuel to be employed instead of traditional energies. Biogas is mainly composed by methane (CH_4) and carbon dioxide (CO_2). To obtain pure biomethane, a proper biogas upgrading to remove CO_2 and other minority compounds is needed. For this purpose, upgrading processes have been developed, such as water or chemical scrubbing, membrane separation, pressure swing adsorption, and cryogenic techniques. Cryogenic techniques represent a good option to be optimized because these techniques yield high-purity products, ranging between 95 and 99%. Therefore, we present here a review on cryogenic techniques. In spite of many advantages, the high-energy penalty makes cryogenic techniques commercially inapplicable actually. Several authors have proposed novel configurations to reduce the energy consumption. Cryogenic packed-bed technology was recently tested in a coal-fired plant with an energy consumption of 1.8 MJ/kg CO_2. Economic analyses were carried out for anti-sublimation CO_2 capture, giving a cost of 34.5 €/ton CO_2. Among the different alternatives of cryogenic hybrid systems, cryogenic membrane processes stand out due to a 54.4% of capital cost savings.
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Biogas upgrading by cryogenic techniques
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10.1007/s10311-019-00872-2
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2019-09-01
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In this paper, a new high-temperature superconducting (HTS)-based microwave radiometer with an improved sensitivity is presented. The cryogenic receiver front end consists of an HTS filter and a cryogenic low noise amplifier (LNA). The cryogenic receiver front end shows an ultra-low noise figure and can suppress radio frequency interference (RFI) effectively. The proposed HTS filter works at a center frequency of 1.4135 GHz with a bandwidth of 25 MHz. The measured mid-band insertion loss, side band steepness, and out-of-band attenuation of the HTS filter are 0.14 dB, 35 dB/MHz, and 80 dB, respectively. The noise figure of the cryogenic LNA is about 0.27 dB at a temperature of 77 K. Compared with other total power radiometers, the proposed radiometer has a lower receiver noise temperature, which can improve the sensitivity with a short integration time of the satellite-based salinity meter. In addition, since the bandwidth of the salinity meter is fixed and the integration time of satellite-based equipment is limited, such a low receiver noise temperature can increase the flexibility of future satellite payload configuration program.
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A High-Order L-Band HTS Filter for Sensitive Detecting
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10.1007/s10948-019-5070-z
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2019-09-01
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A numerical study of the performance of a single-stage Gifford–McMahon refrigerator was performed. A description of the mathematical model of the refrigerator operating with an unsteady flow of helium is given. Adequacy of the mathematical model was confirmed by comparing its results with published reliable data on tests of a refrigerator with cooling capacity of 30.2 W at 80 K. Using the wave approach, a method was developed that made it possible to study the time behavior of helium temperatures at direct and counter-flow helium blow at the regenerator inlet and outlet, as well as packing in its middle part. It is shown that for small amplitudes of temperature fluctuations, it is possible to reduce the length of the regenerator by 20–25% without diminishing its performance indicators. From the analysis of the operation of a single-stage cryogenic refrigerator, it is established that the main source of thermodynamic losses in it is the substantial non-equilibrium heat exchange between helium in the cold cavity and the wall of the working cylinder. A two-fold increase of heat transfer surface in the cold cavity will increase the cooling capacity of the refrigerator by 25%, i.e., up to 37.9 watts.
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Improving the Efficiency of a Gifford–Mcmahon Cryogenic Refrigerator
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10.1007/s10556-019-00636-3
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2019-09-01
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Mechanical properties of two high-strength metallic alloys, fabricated using additive manufacturing (AM) technology, were characterised down to − 269 °C. A test setup has been developed to accommodate the specific sample geometry and manufacturing conditions for these tests. Tensile, compression, pin-bearing, and shear tests were performed at room temperature, − 73 °C, − 196 °C, and − 269 °C. Test equipment and fixtures were designed and optimized to survive the test loads up to 100 kN at low temperatures. Instrumentation for strain, temperature, and displacement was also carefully chosen to record the specimen behaviour and apply the test requirements. The KRP cryo apparatus provided fast cooling and temperature stability during the entire duration of testing. In this paper, we describe the design of the test apparatus, the challenges in development and some results of test runs.
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Innovative setup for cryogenic mechanical testing of high-strength metallic alloys
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10.1007/s12567-019-0239-7
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2019-09-01
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Abstract— A destructive peat horizon T_md of bare peat circles on flat-topped peat mounds in the north of Western Siberia differs from peat horizons (T) of typical peat soils in its higher density, water content, and comminution of peat residues; lower microbial biomass; low mineralization and hydrolase activities; low physiological diversity of hydrolytic bacteria; and specific composition of the fungal complex with an uncharacteristically high proportion and quantity of psychrophilic yeasts Leucosporidium drummii . Specific respiration rate and hydrolase activity in the T_md and T horizons are relatively close, which indicates that, in general, the metabolic activity of microorganisms decomposing the organic matter of peat and increasing the degree of peat decomposition remains unchanged in the soils of bare peat circles.
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Microbiological Characteristics of Bare Peat Circles on Flat-Topped Peat Mounds in the North of Western Siberia
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10.1134/S1064229319090114
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2019-09-01
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Abstract —Cryogenic treatments including shallow and deep cryogenic treatment are supplemental operations designed to improve wear resistance and increase the hardness of a variety of tool and hardening steels. In this research, the effect of cryogenic treatment was investigated on the microstructure and wear behavior (wear behavior in environment temperature and at 550°C) in H11 hot work tool steel. To do so, the samples were austenitized in 1050°C for 60 min and were quenched in oil. Then, the samples were put into dry ice (‒80°C) and liquid nitrogen (–196°C) under shallow and deep cryogenic treatments. Later, the samples were tempered at 550°C for 60 min. Scanning electron microscopy (SEM), optical microscopy (OM), and X-ray diffraction (XRD) analysis were used to analyze the microstructure and the pin on disk method was used to analyze the wear behavior. The results showed that the percentage of retained austenite reaches from 6.5% in quench–temper treatment (QT) to 3% in shallow and to less than 1% in deep cryogenic treatments. Moreover, the tiny carbides are generated (after tempering at 550°C) as a result of deep cryogenic treatment (DCT) and the amount of carbides reaches from 5.5% in QT treatment to 8.2% in DCT treatment. Moreover, in both deep and shallow cryogenic treatments compared to a quench-temper one with the hardness of 4 and 9%, wear resistance at ambient temperature reached 31 and 36% and the wear resistance at high temperature reached 30 and 40%. Additionally, the wear mechanism becomes an adhesive and tribochemical wear in the environment temperature and becomes an abrasive and tribochemical wear in the high temperatures. Conducting cryogenic treatment reduces the amount of adhesive and abrasive wear at the environment and high temperatures.
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The Effect of Deep Cryogenic Treatment on Microstructure and Wear Behavior of H11 Tool Steel
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10.1134/S0031918X19090035
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2019-09-01
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Abstract —This study investigated the effect of deep cryogenic treatment (DCT) on the aging processes of Al–0.43Mg–1.27Si alloy. Differences in the mechanical properties and precipitation behavior between conventional treatment and DCT were analyzed by means of hardness test, tensile test, optical microscopy (OM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and transmission electron microscopy (TEM). DCT promoted the precipitation of Si phases, which is accompanied by an increase in hardness. The content of Si was improved from 0.84 to 1.08% and the hardness was increased from 46.11 to 48.89 HV. The temperature of precipitation of GP zones and β'' phase was lower, which accelerated precipitation of the β'' phase and then improved the aging hardening response of the alloy.
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Effect of Deep Cryogenic Treatment on Aging Processes of Al–Mg–Si Alloy
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10.1134/S0031918X19070111
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2019-08-15
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The present study concerns the cryogenic processing of metals with simultaneous analysis of x-ray diffraction in a synchrotron ring. The mechanical properties improvement related to cryogenic processing of metals is attributed to the partial suppression of dynamic recovery. Thus, commercially pure metals with different stacking fault energies (silver, copper and aluminum) were deformed by uniaxial tensile tests and characterized by in situ x-ray diffraction, at room (293 K) and cryogenic (77 K) temperatures. The cryogenic processing allows a simultaneous improvement in ductility and strength for silver and copper and an improvement in strength for aluminum. This difference in mechanical properties was investigated by means of variations in crystallite size, microstrain and also the amount and size of dimples on the fracture surface. The microstructural refinement at cryogenic temperatures shows a tendency related to the stacking fault energies.
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In Situ X-Ray Diffraction Analysis of Face-Centered Cubic Metals Deformed at Room and Cryogenic Temperatures
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10.1007/s11665-019-04226-5
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2019-08-15
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A numerical model is developed to study fluid sloshing behavior in a liquid oxygen tank. Both external heat leak and the interfacial phase change are considered. The volume of fluid method is adopted to predict the interfacial fluctuation with the mesh motion treatment coupled. A sinusoidal wave is realized by the user-defined functions and is imposed on the tank to simulate the external excitation. The numerical model is in reasonable consistency with the experimental data, and the relative errors are less than 3.0%. On the basis of the numerical model, the effect of the initial liquid temperature on fluid sloshing is investigated. The pressurization performance, including pressure variations of the vapor and liquid monitors, and the vapor condensation are analyzed. Meanwhile, the sloshing force and moment are investigated. Finally, the interface dynamic fluctuation is analyzed by monitoring the elevation variations of different interfacial test points. The results infer that the initial liquid temperature has great effects on the fluid pressure distribution and the sloshing force suffered by the tank, while its influences on the sloshing moment and interface dynamic response are not obviously reflected.
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Sloshing Behavior Under Different Initial Liquid Temperatures in a Cryogenic Fuel Tank
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10.1007/s10909-019-02167-w
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2019-08-01
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The formation and evolution of permafrost in China during the last 20 ka were reconstructed on the basis of large amount of paleo-permafrost remains and paleo-periglacial evidence, as well as paleo-glacial landforms, paleo-flora and paleofauna records. The results indicate that, during the local Last Glacial Maximum (LLGM) or local Last Permafrost Maximum (LLPMax), the extent of permafrost of China reached 5.3×10^6−5.4×10^6 km^2, or thrice that of today, but permafrost shrank to only 0.80×10^6−0.85×10^6 km^2, or 50% that of present, during the local Holocene Megathermal Period (LHMP), or the local Last Permafrost Minimum (LLPMin). On the basis of the dating of periglacial remains and their distributive features, the extent of permafrost in China was delineated for the two periods of LLGM (LLPMax) and LHMP (LLPMin), and the evolution of permafrost in China was divided into seven periods as follows: (1) LLGM in Late Pleistocene (ca. 20000 to 13000−10800 a BP) with extensive evidence for the presence of intensive ice-wedge expansion for outlining its LLPMax extent; (2) A period of dramatically changing climate during the early Holocene (10800 to 8500−7000 a BP) when permafrost remained relatively stable but with a general trend of shrinking areal extent; (3) The LHMP in the Mid-Holocene (8500−7000 to 4000−3000 a BP) when permafrost degraded intensively and extensively, and shrank to the LLPMin; (4) Neoglaciation during the late Holocene (4000−3000 to 1000 a BP, when permafrost again expanded; (5) Medieval Warming Period (MWP) in the late Holocene (1000−500 a BP) when permafrost was in a relative decline; (6) Little Ice Age (LIA) in the late Holocene (500−100 a BP), when permafrost relatively expanded, and; (7) Recent warming (during the 20th century), when permafrost continuously degraded and still is degrading. The paleo-climate, geography and paleopermafrost extents and other features were reconstructed for each of these seven periods.
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Evolution of permafrost in China during the last 20 ka
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10.1007/s11430-018-9272-0
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2019-08-01
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The development of space engines with liquid propellants require use of highly engineered bearings. High nitrogen martensitic stainless steel (HNMS) is the newly developed steel and is the potential candidate for anti-friction bearings in cryogenic engines in launch vehicles. The present paper aimed to assess the effect of cryogenic treatment on HNMS steel at sub-zero temperature regimes. HNMS steel specimens were treated using optimised heat treatment cycle comprising of hardening at 1075 °C, cryogenic treatment at − 196 °C for 8 h followed by soft tempering at 100 °C for 1 h. The specimens were tested for hardness, wear loss (test load 20–80 N), surface roughness, and impact toughness from room temperature (RT) to the cryogenic temperatures. Worn surfaces, subsurface features, and fractured surfaces were analysed using FE-SEM. It was established that the HNMS steel showed reduced wear rate by 28% and 60% for 20 N and 80 N wear test load, respectively, at − 196 °C as compared to the RT. Severe delaminated wear mechanism was observed at RT as compared to mild adhesive wear at − 196 °C. Impact testing revealed that the DBTT for HNMS steel lied between − 30 and − 60 °C .
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Studies on Wear Behaviour and DBTT in Sub-zero Regimes of Cryo-Treated High Nitrogen Martensitic Stainless Steel (HNMS)
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10.1007/s12666-018-01555-2
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2019-08-01
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Abstract Pintle injector has the advantages of wide throttle-ability by sustaining high combustion efficiency and weight lightening by replacing multi-injector elements with a single injector element. However, compared to typical injectors with a fixed shape, like shear coaxial or coaxial swirl injector, there are many complex variables owing to the moving parts. In this study, using cryogenic liquid nitrogen and gaseous nitrogen as simulants, experiments on cryogenic nitrogen spray visualization were performed to simulate cryogenic oxygen and gaseous methane combustion experiments. Experimental conditions were varied by changing the pintle tip angle, pintle opening distance, and simulant supplying pressure. With the visualization images, the spray angle of cryogenic spray was obtained and compared with the previous empirical equations. The former empirical equation between total momentum ratio and spray angle is not well matched, but the other equation between velocity ratio and spray angle fits well with experimental result, through modification of parameter. Graphical abstract
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Flow visualization of cryogenic spray from a movable pintle injector
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10.1007/s12650-019-00548-7
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2019-08-01
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Aramid fiber–reinforced epoxy resin matrix composite is an anisotropic and heterogeneous material. And the machinability is strongly dependent on the fiber orientation. In this paper, a composite milling model was established based on fiber orientation θ . Meanwhile, a series of cryogenic cooling milling experiments were carried out to research the influence of fiber orientation on surface morphology, surface roughness, milling force, and tool wear. The results show that the acute angle milling has more advantages than the obtuse one. When tool sweeps at about θ = 55°, the maximum milling force can be gotten. And the maximum shearing action can be reached for latitude fiber at θ = 30°, as well as effectively chip broken for latitude and longitude fibers. Similarly, with increased θ , the shearing fracture is weakened with insufficient chip breaking, but none affected for longitude fibers. Besides, it can be predicted that when the cutting speeds are 50, 100, and 150 m/min, as well as fiber orientation 26°, 34°, and 35°, respectively, the processed surface roughness is 0.93 μm, 0.71 μm, and 0.6 μm. At the same time, tool wear is relatively serious with θ = 40° with a stable tool wear stage, and the processing effect is not affected. Furthermore, using the bigger cutting parameters, the better cryogenic cooling milling effect can be obtained at fiber orientation near 30° with less burr defect.
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Milling properties of Kevlar 49 fiber composite based on fiber orientation in cryogenic cooling
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10.1007/s00170-019-03933-6
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2019-07-19
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In this present research, a cryogenic machining system with adjustable jet temperature (− 196~20 °C) has been developed, and then a series of cutting experiments have been conducted to investigate the surface integrity of 35CrMnSiA high-strength steel under dry machining and cryogenic machining. The influences of cutting speed, jet temperature, and cooling condition on cutting force, surface roughness, microhardness, microstructure, and residual stress have been investigated. Experimental results are evaluated by means of a surface roughness tester, digital microhardness tester, digital microscope, and X-ray diffractometer. The experimental results reveal that the jet temperature, cooling condition, and cutting speed have a remarkable influence on the cutting force and surface integrity of 35CrMnSiA high-strength steel. At the same cutting speed, a reduction in jet temperature results in an increase in cutting force and decrease in microhardness. The lower jet temperature, the smaller the surface roughness. Compared with dry machining, the tensile residual stress can be effectively reduced under the condition of cryogenic machining. At the same jet temperature, as the cutting speed increases, the cutting force increases firstly and then decreases. In contrast, the surface roughness decreases firstly and then increases. With the increase of cutting speed, under the same cooling condition, the microhardness and residual stress shows a decreasing and increasing trend, respectively. This research contributes to providing a guide to optimize the machining process and improve machined surface integrity.
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Experimental study on surface integrity in cryogenic milling of 35CrMnSiA high-strength steel
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10.1007/s00170-019-03577-6
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2019-07-11
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The effects of cryogenic treatment (CT) and tempering-cryogenic treatment (TCT) on the microstructure and properties of coarse-grained WC–10Co cemented carbides with different carbon contents were researched. The binder phase, WC mean grain sizes, W solubility in the binder, relative magnetic saturation, densities, hardness, wear resistance and second phase precipitation of cemented carbides with different heat treatments were discussed. The results show that there are significant changes of microstructure and properties in the samples with CT and TCT, especially due to the precipitation of metastable nanoparticles $${\text{W}}_{x} {\text{Co}}_{y} {\text{C}}_{z}$$ W x Co y C z in the binder during the heat treatments of CT and TCT. With the simultaneous combination of microstructure and nanoparticle-reinforced binder, a dramatically improved combination of hardness and wear resistance of the samples after TCT has been achieved.
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Microstructure and properties of coarse-grained WC–10Co cemented carbides with different carbon contents during heat treatments
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10.1007/s12598-019-01276-5
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2019-07-11
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PrFeB magnets, which possess excellent magnetic properties at low temperatures, have important application value as cryogenic permanent magnet undulators for synchrotron radiation sources and free electron lasers. In this research study, several high-performance PrFeB magnets (P42H, P48SH, and P48UH) were prepared, and their performance was comprehensively examined, including evaluations of their magnetic properties, microstructures, uniformity, and stability. Next, their application prospects were analyzed and discussed. In China, the first cryogenic permanent magnet undulators (CPMUs) with P48SH magnets with 18 mm cycle lengths have been developed. When the temperature is 80 K and the gap is 6.0 mm, the magnetic field measurement results of the CPMU showed that the effective magnetic field peak was approximately 0.92 T, yielding an increase of 11.76% relative to operation at 300 K, with an RMS phase error of about 4.99°.
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Research on the comprehensive performance of PrFeB magnets for synchrotron radiation and free electron laser
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10.1007/s41365-019-0640-0
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2019-07-01
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In this study, the high strain rate behavior of ultrafine grained (UFG) AA2219 alloy processed via multi axial forging at cryogenic temperature was investigated. Room temperature forged sample was used as a reference to determine the effects of significant grain size refinement on the dynamic response of the materials. The initial microstructure characterization indicated that severe plastic deformation in the cryogenically process alloy resulted in its grain size reduction to ~ 270 nm and the second phase breakage to finer particles. The results of the dynamic impact tests show that the strain hardening and thermal softening are substantially less significant in the UFG materials, whereas the maximum flow stress and the strain rate sensitivity increased. Furthermore, the grain size reduction led to the absorption of higher portion of the deformation energy and an increase in the toughness of the fabricated UFG material when compared to the conventionally forged samples. This improvement is approximately 56% at a strain rate of 4000 s^−1 obtained via the grain structure refinement. Microstructure analysis of the post-deformed samples revealed two fully transformed adiabatic shear bands (ASBs) in the coarser grained material due to intense localized strain and thermal instability during the impact tests which caused the pushing off of the second phases and cracks formation inside the ASBs. However, low-intensity deformed ASBs and a notable enhancement in crack initiation strength were observed by morphology and final configuration of the post-deformed UFG samples. In addition, no considerable hardness variations were experienced in the impacted UFG material due to the saturation of grain size during the cryogenically forging process. In contrary to the UFG alloys, significant hardness increase was observed in the deformed coarse grained material which was associated with softening in the adjacent regions providing a zone prone to cracks initiation.
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Dynamic Failure Investigation in Ultrafine Grained AA2219: Mechanical and Microstructural Analysis
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10.1007/s12540-019-00254-x
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2019-07-01
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To determine the effect of liquid nitrogen (LN_2) cooling on the damage of heated rock, we conducted a series of physical and mechanical tests on Shandong granite samples. These granites were first slowly heated to the target temperatures (25~600 °C) and held for 10 h, followed by rapid cooling with a coolant. Three coolants were used and compared in our experiment: air, water and LN_2. Physical properties and mechanical properties were tested after thermal treatments. Microstructural changes were also observed using scanning electron microscope and optical microscope. According to experimental results, permeability of the heated granites increases significantly after LN_2-cooling, while density, P-wave velocity, strength and elastic modulus reduce. As heating temperature rises, changes in these properties become more pronounced. Compared to air-cooling and water-cooling, LN_2-cooling induces greater changes in the physical and mechanical properties at any target temperature. This indicates that LN_2-cooling can damage the heated rocks more remarkably than the other two cooling treatments. According to microscopic analysis, inter-granular cracking is the primary failure mode during thermal treatment, and most of the inter-granular cracks distribute at the boundaries of quartz. Our results in this paper are of great value for understanding the characteristics of thermal damage induced by rapid cooling.
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Variations of Physical and Mechanical Properties of Heated Granite After Rapid Cooling with Liquid Nitrogen
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10.1007/s00603-018-1727-3
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2019-07-01
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For higher tool life of cutting inserts cryogenic treatment is considered as the most prominent method but no substantial researches have been found concerning the impact of cryogenic treatment on cermet inserts especially in hard turning. Therefore, in the present experimental investigation, the comparative assessment of various responses such as cutting force, flank wear, crater wear, chip morphology and surface roughness were carried out during machining of hardened steel with both untreated and cryo treated cermet inserts hard turning under dry cutting condition. Lastly, the input variables were optimized using Response surface methodology (RSM) to evaluate the tool life for the economic analysis. The experimental result demonstrated that the uncoated deep cryo treated with tempered cermet insert delivered better results in comparison to other cermet inserts. According to cost analysis, uncoated and deep cryo treated with tempered cermet insert was found to be the most economical among other cermet inserts at the optimum cutting condition.
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Machinability Investigation and Cost Estimation During Finish Dry Hard Turning of AISI 4340 Steel with Untreated and Cryo Treated Cermet Inserts
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10.3103/S1063457619040051
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2019-07-01
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High demand of lightweight material makes magnesium alloys and composites more suitable to aerospace and automotive industries. However, poor corrosion resistance and fatigue resistance make its applications limited. Due to inherent capability of machining processes, the surface characteristics of the component can be improved. Many articles reported improvement in machinability of different difficult-to-machine materials while using ultrasonic-assisted turning (UAT) process and cryogenic-assisted turning individually. In this paper, the newly developed cryogenic–ultrasonic-assisted turning (CUAT) technique is used for the machining of in-house developed magnesium AZ91/SiC particulate metal matrix composite (PMMC). In this study, surface roughness and chip breakability index are measured under different machining methods, i.e. conventional turning (CT), UAT and CUAT. The full factorial method is used to design the experiments. A regression model of surface roughness is developed for CT and UAT processes and optimized using Jaya algorithm. Our results provide evidence of improvement in surface finish for UAT of magnesium AZ91/SiC PMMC in comparison with CT. An improvement up to 36.50% and 15% has been observed in surface roughness and chip breakability index, respectively, with CUAT process as compared to UAT process at optimized cutting parameters of the UAT process.
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Effect of Hybrid Machining Techniques on Machining Performance of In-House Developed Mg-PMMC
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10.1007/s12666-019-01652-w
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2019-07-01
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One of the key problems in the ICF program is the development of rapid methods for forming cryogenic fuel targets (CFT) for their feeding to the focus of a high-power laser setup or an ICF reactor. The simulation results on temporal parameters of the formation of reactor-scaled CFTs by the free-standing target (FST) method are presented. The CFT design includes hollow 4-mm-diameter shells of compact and porous polymers, containing solid hydrogen fuel on the inner surface. It is shown that the time of the cryogenic layer formation in the targets does not exceed 30 s, which makes it possible to implement line production of reactor-scaled CFTs based on the FST method.
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FST-Layering of High-Gain Direct-Drive Cryogenic Targets
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10.3103/S1068335619070054
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2019-07-01
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Special features of the structural and mechanical behavior of aluminum alloy D16 under equal-channel angular pressing (ECAP) and subsequent cooling to cryogenic temperatures are studied. The mean grain size, the conventional yield strength, and the elongation are determined. It is shown that the ECAP refines the grains and raises the strength properties of the alloy.
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Effect of Cryogenic Cooling After Ecap on Mechanical Properties of Aluminum Alloy D16
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10.1007/s11041-019-00406-1
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2019-07-01
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A complex mathematical model of the thermo-deformed state of a circular cylindrical shell reinforced by stringers for a vertically installed cryogenic tank during its filling was constructed. The model describes the local deviation of the shell generatrix due to the nonuniform temperature distribution and the action of an axial compressive load. Relations describing the temperature distribution along the shell and its radial displacement were obtained. The quantitative analysis of these relations was carried out. Estimations of the shell generating line deviation from the original rectilinear form, which can decrease the level of the critical axial loads and cause the shell buckling, are presented.
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Deformation of the Shell of the Cylindrical Cryogenic Tank during its Filling
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10.3103/S1068799819030024
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2019-06-19
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Owing to superior physio-chemical characteristics, titanium alloys are widely adopted in numerous fields such as medical, aerospace, and military applications. However, titanium alloys have poor machinability due to its low thermal conductivity which results in high temperature during machining. Numerous lubrication and cooling techniques have already been employed to reduce the harmful environmental footprints and temperature elevation and to improve the machining of titanium alloys. In this current work, an attempt has been made to evaluate the effectiveness of two cooling and lubrication techniques namely cryogenic cooling and hybrid nanoadditive–based minimum quantity lubrication (MQL). The key objective of this experimental research is to compare the influence of cryogenic CO_2 and hybrid nanofluid–based MQL techniques for turning Ti–6Al–4V. The used hybrid nanofluid is alumina (Al_2O_3) with multi-walled carbon nanotubes (MWCNTs) dispersed in vegetable oil. Taguchi-based L9 orthogonal-array was used for the design of the experiment. The design variables were cutting speed, feed rate, and cooling technique. Results showed that the hybrid nanoadditives reduced the average surface roughness by 8.72%, cutting force by 11.8%, and increased the tool life by 23% in comparison with the cryogenic cooling. Nevertheless, the cryogenic technique showed a reduction of 11.2% in cutting temperature compared to the MQL-hybrid nanofluids at low and high levels of cutting speed and feed rate. In this regard, a milestone has been achieved by implementing two different sustainable cooling/lubrication techniques.
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Effects of hybrid Al_2O_3-CNT nanofluids and cryogenic cooling on machining of Ti–6Al–4V
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10.1007/s00170-019-03485-9
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2019-06-19
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The adiabatic shear band (ASB) is easily generated in high-speed cutting, as well as the serrated chip. The main factors are high temperature and elastoplastic instability. An adiabatic shear energy dissipation model was established and analyzed. A series of milling experiments were systematically conducted with cryogenic and conventional cooling. Meanwhile, the characteristics of the workpiece and chip were investigated and compared. The results show that under the conventional cooling, at the cutting speed of 150 m/min, the ASB and generated serrated chip can be produced with the high-frequency oscillation cutting force. In cryogenic, the chip is serrated at all kinds of cutting speed, especially high speed, and the sawtooth is regular with no obvious ASB. The serrated chip formation is mainly associated with brittle cutting in cryogenics. When the cutting parameters are unchanged, the energy dissipation is mainly determined by the main cutting force and shear strength. Compared with the conventional cooling process, the energy dissipation in cryogenic is more than the former one, and the ability of producing instantaneous adiabatic shear is weaker. Furthermore, due to the instantaneous cold brittleness of liquid nitrogen, the generating condition of the ASB is not satisfied in the shear zone.
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Effect of cryogenic cooling on adiabatic shearing in processing titanium alloy
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10.1007/s00170-019-03380-3
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2019-06-15
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El virus de la papa S (PVS) es uno de los más difíciles de eliminar por termoterapia debido a su punto de desactivación térmica. Los pretratamientos de ácido salicílico (AS) se han probado con éxito en métodos criogénicos para reducir el daño oxidativo y para la limpieza del virus mediante termoterapia. En la presente investigación, se estudió el efecto de AS como protector al daño oxidativo por crioterapia en plantas de Solanum tuberosum infectadas con PVS. Genotipos vulnerables a protocolo criogénico fueron seleccionados y probados con dos tratamientos de AS. Clones de papa fueron pretratados con AS (0, 10^−5, and 10^−6 M), se evaluó el desarrollo de las plantas y posteriormente se expusieron a crioterapia, seguido de evaluación del desarrollo de las plantas y prueba de presencia de virus. Las plantas tratadas con AS aumentaron las variables evaluadas antes de la crioterapia. Después de la crioterapia, se obtuvo un 66.6–100% de plantas libres de virus en comparación con el testigo, que mostró una supervivencia del 0%. La combinación de crioterapia AS mejoró la supervivencia y, por lo tanto, facilitó la limpieza de virus PVS. Potato virus S (PVS) is one of the most difficult viruses to eliminate by thermotherapy due to its thermal deactivation point. Pre-treatment methods involving salicylic acid (SA) have been successfully carried in conjugation with cryogenic methods to reduce oxidative damage and eliminate viruses. In the present investigation, the effect of SA to protect Solanum tuberosum plants infected with PVS from oxidative damage from subsequent cryotherapy was studied. Vulnerable genotypes to cryogenic protocol were selected, with two SA treatments examined. Potato clones were pretreated with SA (0, 10^−5, and 10^−6 M), plant development was evaluated and then exposed to cryotherapy. This was followed up by a plant development evaluation and virus testing. After the initial treatment with SA, the plants exhibited an increase in the variables evaluated before cryotherapy. After cryotherapy, between 66.6% and 100% of the treated plants were found to be virus-free compared to control plants which exhibited 0% survival. Thus, the SA-cryotherapy treatment combination described appears to enhance plant survival and eliminate PVS from potato plants.
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Salicylic Acid-Cryotherapy Treatment for Elimination of Potato Virus S from Solanum Tuberosum
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10.1007/s12230-018-09694-4
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2019-06-15
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Demand for titanium alloys in different sectors is increasing in recent years due to their outstanding strength-to-weight ratio, ability to retain strength at higher temperatures and resistance to wear. Machining of titanium Ti–6Al–4V has an adverse influence from the premature failure of the tool. Conventional cooling technique fails to reduce the temperature generated at the cutting area attributed to poor surface quality. Liquid carbon dioxide (LCO_2) as a cryogenic coolant has turned into a recent trend in machining as it does not require any expensive method of disposal. This experiment investigates the performance of cryogenic cooling technique in the end milling of Ti–6Al–4V using PVD-TiN-coated tool with a different speed-feed combination. The angle of the nozzle was maintained 45° in the feed direction. The results demonstrated that machining with LCO_2 lowers the cutting temperature by 39.53–57.44% and surface roughness by 48.24–74.77% compared with wet machining. The impact of utilizing LCO_2 as a cryogenic coolant improved the surface and subsurface characteristics.
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Performance Analysis of Machining Ti–6Al–4V Under Cryogenic CO_2 Using PVD-TiN Coated Tool
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10.1007/s11668-019-00667-1
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2019-06-01
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冲剪成形作为一种材料加工方法,经常用于加工一些成品零件。深冷处理在改善钢的局部力学 性能上有显著效果,但有关深冷处理对镁合金冲剪性能影响的研究较少。本文通过金相组织分析、拉 伸、硬度测试和冲剪实验等,分析了深冷处理对AZ31板冲剪性能的影响。结果表明:深冷处理后组 织中第二相数量增加,晶粒中出现大量孪晶。同时,AZ31镁合金的抗拉强度,延展性和硬度均得到 改善,而屈服强度在深冷处理后有所降低。此外,经深冷处理后的AZ31镁合金板在冲剪过程中,剪切强度降低,圆角半径变化不明显,横截面边缘的毛刺高度降低,光亮带所占比例明显增加。 Punch shearing is used to form the part in the material process. Cryogenic treatment (CT) has active effect on local mechanical properties of steel, but it is still uncertain of the influence of CT on the properties of the magnesium alloy during punch shearing. In this work, the influence of AZ31 sheet treated by cryogenic on punch shearing was studied. Microstructures were observed with a ZEISS optical microscope, and mechanical properties, as well as shear properties were tested by tensile testing and punch shearing. The results show that the number of secondary phase increases and a large number of twins appear in the grains after CT. Meanwhile, the ultimate tensile strength (UTS), the ductility, and hardness of AZ31 are improved, while the yield strength (YS) decreases gradually during CT. During punch shearing, the shearing strength decreases, the rollover radius changes insignificantly, and the height of the burr on the edge of the cross section decreases. At the same time, a larger proportion of smooth zone on the cross section has been achieved.
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Influence of AZ31 sheet treated by cryogenic on punch shearing
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10.1007/s11771-019-4114-7
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2019-06-01
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Metalworking fluids (MWF’s) are frequently used for cooling and lubrication during machining processes in manufacturing industries. MWF’s such as soluble straight oils, synthetic oils, solid lubricants, bio lubricants contain a mix of water and mineral oil with some percentage of vegetable oils and petroleum. These MWF’s are hazardous for the environment and for human health. After using, the lubricants are disposed into the environment by burning or by dumping on the ground or in the sea water. Burning the lubricant creates pollution and airborne disease. To avoid these harmful effects of the lubricants sustainable machining technique is implemented in machining processes. In the present study, liquid nitrogen (green coolant) is used as a sustainable machining technique for cooling and lubrication. Finite element modeling is used to simulate the micro-end milling at different conditions of the workpiece (cryogenic plus preheated and cryogenic). The analysis of chip morphology and cutting forces measurement were done by applying these conditions. The predicted model is validated with the experimental results. It was observed that cryogenic with preheated workpiece (473 K) is the optimum condition with the application of green coolant. This study will clarify the behavior of cryogenic on the machining conditions and will solve the environmental problems.
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Replacement of Hazard Lubricants by Green Coolant in Machining of Ti6Al4V: A 3D FEM Approach
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10.1007/s12541-019-00111-2
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2019-06-01
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Cryogenic turning of metastable austenitic steels allows for a surface layer hardening integrated into the machining process, which renders a separate hardening process obsolete. This surface layer hardening is the result of a superposition of strain hardening mechanisms and deformation-induced phase transformation from austenite to martensite. The activation energy required for the latter depends on the chemical composition of the metastable austenitic steel. It can hence be expected that the austenitic stability of the workpiece material varies depending on the batch and that differences in the metallurgical surface layer properties and thus also in the microhardness result after cryogenic turning. Therefore, in this paper, various batches of the metastable austenitic steel AISI 347 were turned utilizing cryogenic cooling with the same machining parameters. The thermomechanical load during the experiments was characterized and the resulting subsurface properties were investigated. The content of deformation-induced α′-martensite was quantified via magnetic sensor measurements and the distribution was examined using optical micrographs of etched cross-sections. It was found that similar amounts of deformation-induced α′-martensite were generated in the workpiece surface layer for all batches examined. Furthermore, the workpieces were analyzed with regard to the maximal hardness increase and the hardness penetration depth based on microhardness measurements. A significant surface layer hardening was achieved for all batches. This shows that surface layer hardening integrated in the manufacturing process is possible regardless of batch-dependent differences in the chemical composition and thus varying austenite stability of the metastable austenitic steel.
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Generation of deformation-induced martensite when cryogenic turning various batches of the metastable austenitic steel AISI 347
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10.1007/s11740-018-00873-0
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2019-06-01
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Combustion of cryogenic propellants is of great technological interest for researchers and scientists nowadays. Due to high specific impulse, the use of liquid oxygen and hydrogen as cryogenic propellants will have preferences in the years to come. In the present study, RCM-3 configuration of MASCOTTE test facility is used for the investigation of supercritical cryogenic fuel combustion. The injector of this test case is a shear-coaxial injector consisting of a core of liquid oxygen surrounded by a high-speed flow of gaseous hydrogen. Pressure-based steady-state 2D axisymmetric scheme with non-premixed combustion model and compressibility effect under non-adiabatic conditions is used in the present study. Rich fuel stream flammability limit of 0.2 is used to accommodate non-equilibrium effects. Simulations are carried out for different turbulence models with ideal and real gas assumptions. Pressure-implicit with splitting of operators is used for pressure–velocity coupling while standard k – $$\varepsilon $$ ε , standard k – $$\omega $$ ω , and SST k – $$\omega $$ ω turbulence models are used for the parametric study. Effects of ideal gas and real gas assumptions are also studied. A very low value of under-relaxation factor for density (0.01) is used to encounter stability issues. Computed results show that SST k – $$\omega $$ ω turbulence model with real gas assumptions provide qualitatively as well as quantitatively reasonable and encouraging results. Although peak temperature value is under-predicted, its location and temperature profile along the axis are accurately predicted through real gas assumption, whereas results with ideal gas are far away from experimental values. This provides conclusive evidence that the ideal gas assumption is not appropriate for fluids in the cryogenic state as liquid oxygen in the present study. Improved modeling and inclusion of detailed chemical kinetic mechanism will provide much improved results. Present results are very promising and encouraging to use CFD for the simulation and modeling of cryogenic fuel combustion in the supercritical state.
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Numerical Simulation of Liquid Fuel Injection in Combustion Chamber
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10.1007/s13369-019-03774-1
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2019-05-15
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The influence of the packing material and porosity in a lower stage of a regenerative heat exchanger on the operating efficiency of a GM cryocooler has been studied. Experiments were used to quantify the decrease in cooling capacity when replacing lead by tin. It is found that reduction in the porosity of the material leads to a decrease in cooling capacity of the cryocooler.
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Influence of the Properties of Regenerative Heat Exchanger Packing Material on the Efficiency of a Gifford–Mcmahon Cryocooler
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10.1007/s10556-019-00593-x
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2019-05-01
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The microstructure distribution and distortion behavior of a cold work tool steel cylindrical specimen with keyway after quenching (QT) and deep cryogenic treatment (DCT) were evaluated in detail. Furthermore, from the viewpoints of thermal and volumetric strains, an attempt was made to reveal its distortion mechanism during QT and DCT. The results suggest that DCT can effectively improve the dimensional stability of specimen and eliminate the distortion caused by QT. During the QT and DCT processes, the bending direction and the curvature change of specimen are closely associated with the competition between the thermal strain induced by thermal contraction and the volumetric strain caused by martensite transformation. After DCT, the average thermal and volumetric strains of specimen are respectively about − 0.0051 mm/mm and 0.0049 mm/mm, which are decreased by about 100% and increased by around 25% compared with that of QT, respectively. During QT, the distortion behavior of specimen is governed primarily by the volumetric strain and it mainly undergoes an expansion deformation. While, during DCT, the distortion behavior of specimen is dominated by the thermal strain and it primarily encounters a contraction deformation. However, compared with the expansion deformation during QT, the contraction deformation of specimen during DCT is much more significant, which further proves that DCT is feasible to improve the dimensional stability of specimen.
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Analysis of Distortion Mechanism of a Cold Work Tool Steel During Quenching and Deep Cryogenic Treatment
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10.1007/s12540-018-00220-z
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2019-05-01
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Painted surfaces are useful for thermal control in spacecrafts. Knowledge of emissivity of such painted surfaces over the range of working temperatures is critical in eventually deciding the adequacy of any thermal control strategy. In view of the very low temperatures involved and also because of the variation of temperature in the spacecraft, the emissivity is invariably a function of temperature, which makes its determination formidable and challenging. A “straight forward” technique to measure or estimate emissivity at cryogenic temperatures is to use a steady state calorimetric technique coupled with energy balance. This involves heat transfer by radiation under steady state conditions between an evacuated cryogenic shroud and a heated test sample, centrally suspended inside the shroud. Apart from the heat supplied, knowledge of temperatures, the internal surface area and emissivity of the shroud is required to estimate the emissivity of the unknown test sample. The view factor can be taken care of, if the test sample is much smaller compared to the shroud, resulting in a view factor of 1 between the sample and the shroud. The key difficulty associated with the seemingly simple procedure is the shroud emissivity, which is often unknown at very low cryogenic temperatures. This paper presents a novel experimental approach for the in-situ estimation of cryogenic shroud (coated with ECP2200 paint) emissivity using measured data from experiments on a plane surface substrate and a cavity surface substrate (a surface with an array of hexagonal cavities) coated with an unknown test sample (Aeroglaze Z307 paint). For an average cryogenic shroud temperature of 32.53 K, the shroud emissivity has been estimated to be 0.355. Following this, the emissivities of the plane surface substrate and the cavity surface substrate coated with Aeroglaze Z307 are estimated. The associated measurement uncertainties are systematically quantified and presented.
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Emissivity estimation of spacecraft thermal control surfaces at cryogenic temperatures – a novel experimental approach
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10.1007/s00231-018-2513-1
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2019-05-01
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Currently, cryogenic coolants are used instead of normal cutting fluid in transferring excessive heat from the cutting region and retaining cutting tool edge sharpness during the machining process, and to eliminate the hazardous effects of cutting fluids. In this investigation, end milling experiments with various cooling approaches were performed on DIN 1.2714 die steel using titanium aluminum nitrate-coated carbide tool inserts under dry, conventional coolant, and cryogenic CO_2 environments. The end milling performance under CO_2 environment has been compared with those under dry and wet conditions regarding cutting temperature ( T _ c ), feed force ( F _ x ), normal force ( F _ y ), axial force (F_z), surface roughness ( R _ a ), tool wear, surface and chip morphology, and residual stress. The consequences of these machining environments were evaluated. Using cryogenic CO_2 cooling technique reduced the T _ c values by approximately 50.49 % and 64.42 % compared with those of wet and dry conditions, respectively. Similarly, CO_2 cooling diminished the cutting forces, namely, F _ x , F _ y and F _ z . As a result, R _ a values reduced by approximately 59.81 % and 67.15 % compared with those of wet and dry conditions, respectively. Cryogenic CO_2 caused a significant reduction in surface damage and abrasion wear in the machined surfaces and cutting inserts, respectively. No substantial changes in residual stress were observed at the cut surfaces.
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End milling of DIN 1.2714 die steel with cryogenic CO_2 cooling
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10.1007/s12206-019-0439-2
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2019-04-15
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We have designed and characterized a cryogenic amplifier for use in $$^3$$ 3 He NMR spectrometry. The amplifier, with a power consumption of $$\sim 2.5$$ ∼ 2.5 mW, works at temperatures down to 4 K. It has a high-impedance input for measuring a signal from NMR resonant circuit, and a 50 $${\Omega }$$ Ω differential input which can be used for pick-up compensation and gain calibration. At 4.2 K, the amplifier has a voltage gain of 45, output resistance 146 $${\Omega }$$ Ω and a 4.4 MHz bandwidth starting from DC. At 1 MHz, the voltage and current noise amount to 1.3 $$\text{ nV }/\sqrt{\text{ Hz }}$$ nV / Hz and 12 $$\text{ fA }/\sqrt{\text{ Hz }}$$ fA / Hz , respectively, which yields an optimal source impedance of $$\sim 100$$ ∼ 100 k $${\Omega }$$ Ω .
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Cryogenic Differential Amplifier for NMR Applications
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10.1007/s10909-018-02130-1
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