bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermodynamic Process and Analysis of Dilution Refrigerator
Authors: Zheng M W , Wei L J , Pan Z J , Liang J T , Zhao M G , Lin P 
Published: June 2022

AbstractThermodynamic analysis is essential for not only guiding the design of refrigerator, but also studying its operation mechanism. As the core component, the dilution unit plays an important role in deciding the performance of dilution refrigerator. In this study, a coupled thermodynamic model is established by analyzing each component separately for improving the operation of dilution refrigerator. And an optimization calculation based on that model is carried out to obtain some meaningful results on the dilution unit design. The optimal flow rate of the dilution refrigerator under different working conditions are pointed out. By considering the effect of viscous heat on the performance of the heat exchanger, the applicable conditions of the continuous heat exchanger and the methods to overcome the viscous heat are given.
Characteristics of reciprocating speed of a low power consumption 4 K G-M cryocooler
Authors: Masuyama S , Kamiya K , Numazawa T 
Published: June 2022

Abstract
This study is aiming to develop a low power consumption 4 K G-M cryocooler. As a first step, a two-stage G-M cryocooler with a 2 kW class compressor has been tested. The base model of cold head of two-stage G-M cryocooler is RDK-305D (Sumitomo Heavy Industries). We modified its second stage regenerator materials by filling magnetic materials Gd2O2S and HoCu2 spheres. An air-cooled compressor of SA115 (ULVAC CRYOGENICS) that rated input is 1.9 kW at 60 Hz was connected to the cold head. The experimental results showed that the cooling capacity of the second stage of 0.5 W at 4.2 K and the first stage of 25 W at 45 K was achieved with the cold head reciprocating speed of 48 rpm and the compressor electrical input of 2.09 kW. The relative Carnot efficiency of 1.7% at 4.2 K was calculated from the result. A low reciprocating speed of 48 rpm was chosen is to secure the sufficient expansion work in the second expansion space. This is considered an effective method to obtain a large cooling capacity at 4 K by low power compressor.
Comprehensive optimization design of low temperature insulation system of regeneration cryocooler
Authors: Wang Z K , Li L F , Zhou Y 
Published: June 2022

Abstract
The calculation of radiant heat leakage is a part of the design of cryogenic insulation system. The numerical radiation simulation considering geometric structure of cryogenic insulation system is established through Monte Carlo method and view factor. The difference of the multi-layer insulation outer surface temperature is about 0.5% between the simulation and experimental results. Additionally, the structure and shape of the insulation system would make radiation to redistribute between surfaces. The surface would have less heat leakage with large aspect ratio and small radius.
Development of a 20K two-stage Stirling type pulse tube cryocooler with pre-cooling inside second-stage pulse tube
Authors: Li Z. W. , Wang X. T. , Wang Y. N. , Dai W. 
Published: June 2022

Abstract
Cryocoolers working in the liquid hydrogen temperature are important for applications such as cryo-pump, superconductor cooling and cryogenic electronics. This paper analyzes and compares the 20K gas-coupled two-stage Stirling type pulse tube cryocooler with and without pre-cooling. The pre-cooling uses some of the cooling power generated by the first stage cold head to pre-cool the middle of the second stage pulse tube. Given the same input acoustic power, the simulation results show that the cooling capacity of the second stage increase from 0.64 W to 2 W@20 K while the first stage available cooling capacity decrease from 5.84 W to 3 W@77 K when the pre-cooling is used. Meanwhile, the cryocooler relative Carnot Efficiency in terms of acoustic power increases from 10.3% to 14.6%.
Numerical simulation of three-stage gas coupled pulse tube refrigerator
Authors: Fang Chushu , Duan Yanbo , Wang Zekun , Dong Hongyu , Li Laifeng , Zhou Yuan 
Published: June 2022

Abstract
For its compact structure, small mass, no moving parts at low temperature, strong reliability and stability, Stirling pulse tube refrigerator is regarded as a major development direction of small refrigerator at low temperatures. In order to obtain lower no-load cooling temperature and higher cooling efficiency, multi-stage structure is often used in pulse tube refrigerator. In this paper, a model of three-stage gas-coupled pulse tube refrigerator with multi-bypass and double-inlet is designed by SAGE software. The effects of double-inlet and multi-bypass on the gas distribution of multi-stage pulse tube refrigerator are analyzed. The results show that the multi-bypass and double-inlet do not independently affect the minimum temperature of the refrigerator at no-load, and there is a coupling relationship between their opening. The numerical simulation results are of great value for the construction of a three-stage gas coupled pulse tube refrigerator prototype.
50 kJ SMES magnet design optimization using real coded genetic algorithm
Authors: Anand A , Gour A S , Datta T S , Rao V V 
Published: June 2022

Abstract
SMES systems are being made and utilized for various applications i.e. dampening low frequency oscillations, instantaneous voltage drop compensation, pulsating power supply etc. Due to tape like structure of 2G HTS and fabrication limits of long continuous length , SMES coil is made via assembling individual single pancake coil/double pancaked coil in the solenoid or toroid fashion. A SMES magnet is designed optimally, using real coded genetic algorithm, with minimum length as objective function for fxed amount of stored energy(50 kJ), using 2G HTS tape. Simulated binary crossover and polynomial mutation function are used for crossover and mutation respectively. Elitism is also used for faster convergence of genetic algorithm. An minimum length is found for 50 kJ stored energy. Stress calculation is carried out for this confguration.
Methods of speeding up the cool-down of superconducting magnets that are cooled using Small coolers at temperatures below 30 K
Authors: Green Michael A 
Published: June 2022

Abstract
The two primary ways of cooling superconducting magnets with small coolers are by conduction from the magnet to one or more the coolers cold heads through high thermal conductivity straps or by fluid flow through a thermal siphon cooling loop. Both methods have been used for cooling down magnets. The thermal siphon cooling loop can also be used to produce liquid helium or liquid hydrogen within the cooling loop. Over 85 percent of the cooldown time is used to cool a magnet coil from 300 K to 80 K. This is also true when a helium refrigerator is used to cool down a magnet. The primary reason for this is the magnet material enthalpy at 80 K is between 4 and 6 percent of the material enthalpy at 300 K. The cooler refrigeration increases with the cold head temperature, but the magnet material enthalpy increases more. If one wants to speed up the cool-down rate, one must remove the heat faster in the temperature range between 80 K and 300 K. Two primary methods for speeding up the cooldown of magnet that is kept cold using coolers will be presented.
Short review on cryostats with superconducting magnets
Authors: Putselyk S 
Published: June 2022

Abstract
Modern accelerators typically include many components working at cryogenic temperatures, like superconducting (sc) magnets, sc cavities, cooled beam tube, sc undulators. In most of the cases, sc magnets or cavities are used. Sc magnets were intensively developed over the last 50 years, and it is possible to say that for some sc materials, like NbTi or Nb3Sn, the technology reached a maturity. The sc magnets could be installed either in liquid helium reservoirs or be mounted on metallic structures and passively cooled by the thermal conduction. Though there is a large variety of different types of cryostats, some general requirements posted on them by sc magnets, bus-bars or current leads could be seen. In the present paper a short review on cryostats with superconducting magnets is done as well as general design requirements on bus-bars and safety diodes are shortly mentioned. Two typical cryostat types used for scientific needs or industry applications are discussed. Cryostats with high-Tc current leads or magnets are also shortly mentioned.
A Review on Liquid Hydrogen Pool-Boiling Correlations
Authors: Shenton M , Leachman J 
Published: June 2022

Abstract
Recent advances in additive manufacturing and origami fuel bladders challenge the applicability of liquid hydrogen pool boiling correlations developed for metallic substrates. Empirical liquid hydrogen boiling data are compared to correlations available from the literature that model the heat transfer through single phase convection, nucleate boiling, transition boiling, and film boiling. The boiling correlations display a wide range of accuracies for hydrogen and exhibit a discontinuous boiling profile. Many of these equations utilize numeric constants to account for parameters such as geometry or material properties that have not been validated for a wide range of applications. A sensitivity study is presented for each boiling regime’s widely accepted equation, and manipulating the material/fluid properties has a significant impact on calculating the boiling curve for hydrogen in different storage containers. From this review, we identify major areas for improvement of liquid hydrogen boiling correlations including developing an accurate representation of hydrogen’s quantum property nature and expanding applicability to novel materials.
Two-phase pressure drop study for cryosurgical probes using one-dimensional homogeneous model
Authors: Gunjal Anish , Atrey Milind D. , Srivastava Atul 
Published: June 2022

Abstract
Cryosurgery is an effective medical treatment approach for treating solid cancerous malignancy, as it is a minimally invasive treatment therapy. The main aim of cryosurgery is to use extreme cold to destroy abnormal tissues while minimizing damage to healthy surrounding tissue. Recent technological advancements in cryogenics have attracted the attention of many researchers to study the low-temperature cryosurgical devices, generally termed cryoprobes. Saturated Liquid Nitrogen (LN2) from pressurized dewar is fed to the cryoprobe through a transfer hose. The fluid evaporates as it flows downstream because of various heat loads and experiences pressure drop. In this paper, a two-phase pressure drop solver is presented following a simplified one-dimensional analysis to estimate pressure losses occurring throughout the system. A qualitative discussion on the contribution of various pressure drop components is provided. It is observed that the major pressure loss occurs along the length of the cryoprobe tubes. The effect of the cryoprobe tube dimensions on the pressure drop is also studied. It is concluded that the miniaturized probe design demands higher system inlet pressure.
Tensile Properties of 22Cr-12Ni Austenitic Stainless Steel Thick Plates and Bars at Cryogenic Temperatures
Authors: Kato T , Kato Y , Umezawa O , Ono Y , Yuri T , Nishimura A , Kumagai S 
Published: June 2022

Abstract
The tensile properties of XM-19 austenitic stainless steels with thick plates (30 mm thickness), extra-thick plates (100 mm thickness), and rectangular bars (square of 14.3 mm) were examined at cryogenic temperatures. Influence of thermomechanical treatments on the steels was demonstrated. Even though their 0.2 % proof stresses were over 1200 MPa at 4.2 K, there were variations in strength depending on location. Namely, the 1/2t specimen (the position of the half in the thickness) of extra-thick plate showed lower 0.2% proof stress, elongation, and reduction of area at 4.2 K than the 1/4t (the position of the quarter in the thickness) and the thick plates. The effect of grain size on the 0.2% proof stress was clearly described by the Hall-Petch relationship for the materials.
Improved breakdown strength at cryogenic temperature in epoxy nanocomposites by a small amount of SiC nanoparticles
Authors: Miao Z C , Jia P , Wang Y G , Huang R J , Li L F 
Published: June 2022

Abstract
The study of the electrical properties of materials at cryogenic temperature is significant for the design of insulation structures of superconducting equipment. Here, epoxy resin was combined with a small amount of KH650 modified SiC nanoparticles. When the dosage of SiC nanoparticles increased from 0.1% to 0.3%, the DC breakdown strength of the composite increase from 83.93 kV/mm to 97.51 kV/mm at room temperature and from 90 kV/mm to 120 kV/mm at 77 K. Furthermore, we used differential scanning calorimeter (DSC) and dynamic thermomechanical analysis (DMA) to analyze the effect of low-content SiC nanoparticles on the thermal behavior of epoxy resin.
Thermal conductivity measurements of nano-particle-filled epoxies
Authors: Adams J L , Haight A , Michael P C , Bromberg L , Brisson J G 
Published: June 2022

Abstract
For conduction-cooled superconducting magnets to be truly effective, it is necessary to have good thermal conduction from the cooling source through the insulating epoxy resin to the magnet winding. We have developed epoxy resins filled with thermally conductive nanoparticles that have significantly increased thermal conductivities while retaining most of their dielectric and mechanical strengths. Base resins, including CTD101K, were filled with alumina, aluminum nitride, or diamond nanoparticles. A wire-based 3ω method was developed to measure the thermal conductivity of the nano-filled epoxies over the temperature range from 4 K to 300 K. A unique aspect of this experimental setup is the 10 μm diameter Invar wire heating element, which serves as a sensitive thermometer down to 4 K. Measurements show the filled resins have improved thermal conductivity, especially at temperatures of 15 K and higher.
Characterization of Candidate Insulation Resins for Training Reduction in High Energy Physics Magnets
Authors: Haight A E , Haynes M M , Krave S T , Rudeiros-Fernandez J L , Shen T 
Published: June 2022

AbstractSuperconducting magnets are critical components in particle accelerators and are used to generate and sustain the large magnetic fields needed for High Energy Physics programs. One significant issue with current epoxy insulated Nb3Sn magnets is the long training process required before stable magnet performance can be realized. It is believed that training can be significantly reduced by addressing magnet quenching through improvements in the epoxy electrical insulation. In this work, two approaches for insulation modification have been undertaken: (1) addition of thermally conductive fillers to help with quench management and (2) development of insulation resins with high strain capability at cryogenic temperatures. This paper will discuss the characterization of these insulation systems to verify their performance prior to evaluation in subscale Nb3Sn canted cosine theta accelerator dipole magnets.
Thermal Property Measurements of Al-Alloy for Space Cryogenic Missions
Authors: Shinozaki Keisuke , Mizutani Tadahito , Fujii Takenori , Onaka Takashi , Nakagawa Takao , Sugita Hiroyuki 
Published: June 2022

Abstract
In space cryogenic missions, the thermophysical properties of materials must be studied and measured to establish a highly reliable cooling chain. An Al-alloy is a primary material in cryogenic thermal structural designs and is particularly used for providing high thermal conductance of thermal shields and thermal straps. We measured low-temperature properties (the thermal conductivity and the electrical resistivity) of several Al-alloys and found that A6063 had a lower thermal conductivity than that reported previously. We also found that the Al-alloy ST-60, which has equivalent thermal conductivity as pure aluminum, has higher thermal conductivity than A6061 and A6063, and the material is a good candidate for the space cryogenic design at the temperature range between 4K and 300K. These results are critical for the thermal study of upcoming next-generation space astronomy missions, such as LiteBIRD, SPICA and ATHENA.
An investigation of internal heat flux in SiC/AlN/Epoxy composites by mesoscopic simulation
Authors: Zhou Z R , Huang R J , Wang T , Xie S Y , Zhao Y L , Wu S S , Zhao W Y , Wu Z X , Liu H M , Li L F 
Published: June 2022

Abstract
Polymer-matrix composites play an important role as packaging material in superconducting equipment. The research on thermal conductivity of composites by combining computer numerical simulation and reference data can not only save the expenses but also shorten the period of material development. Herein, the internal heat flow of silicon carbide/aluminum nitride/Epoxy composites was simulated by COMSOL finite element software. And the thermal conductivity calculated by the finite element software is compared with the existing thermal conductivity mechanism. Meanwhile, the influence of the fraction, gap distance, interfacial thermal resistance, etc. on the thermal conductivity of composites was analyzed. In short, it can provide a reference for the thermal conductivity design of polymer composites.
The calculation and measurement of electromagnetic energy flows for investigation of critical current estimation for high-temperature superconducting coil by means of pick-up coils
Authors: Omura Junya , Sato Go , Kawagoe Akifumi 
Published: June 2022

Abstract
For practical operations of high-temperature superconducting (HTS) devices, we have proposed a monitoring and diagnosing system to detect the degradations of superconducting properties before normal transitions occur locally in the HTS winding. The proposed system estimates the distributions of critical current indirectly from measurement results of the active power components of the Poynting vector around the monitoring HTS devices conducting ac currents by means of pick-up coils pairs mounted surrounding the HTS devices. For this purpose, it is necessary to solve the inverse problem. In order to estimate the critical current distribution, therefore, it is first necessary to be able to calculate the measurement signal distribution from the critical current distribution of the monitoring coil. This paper first proposes the calculation method of signal distributions measured by our system, next reports the results of the experiments and analysis, which were carried out to verify the validity of the calculation method. A pancake coil wound with Bi-2223 multifilamentary tape exposed to a uniform AC magnetic field was assumed as a monitoring coil in the experiments and analyses. The good agreement between the measured signals obtained from the experiments and the numerical analysis demonstrates the effectiveness of the proposed calculation method of measured signals.
Approaches for High Performance and Thermally Optimized Flexible Cryogenic Microwave Ribbon Cables
Authors: Peek Sherman E. , Shah Archit , Yelamanchili Bhargav , Gupta Vaibhav , Sellers John A. , Tuckerman David B. , Hamilton Michael C. 
Published: June 2022

Abstract
Design, fabrication, and testing of cryogenic cables with thermal performance considerations is presented in this work. Cables were designed with commercial off-the-shelf materials for low-GHz operation in a small form factor. Thermal and microwave simulations were performed during the design of cables. Fabrication processes were developed to create features in Cu-cladding and to successfully deposit thin-film metal in large step-height regions. Post-fabrication processes such as laser machining and connector assembly were used to cutout and interface with fabricated cables. Microwave performance was measured at room temperature and at 4.2 K with comparable results to simulations performed. Cables designed and fabricated in this work provide a solution to thermal and spatial limitations while achieving targeted microwave performance at cryogenic temperatures.
Computational Modelling of Russia’s First 2G-HTS Triaxial Cable
Authors: Clegg M. , Fareed M. U. , Kapolka M. , Ruiz H. S. 
Published: June 2022

Abstract
A better understanding of the interaction between three phases is required when developing superconducting cables for high voltage AC systems. With a particular focus on the energy losses of real power transmission cables, in this paper we utilize the so-called H-formulation of Maxwell equations to devise a 2D model for superconducting triaxial cables. The major aim of this model is to comprehend and reproduce the experimental observations reported on the first triaxial prototype cable developed by SuperOx and VNIIKP. The computationally modelled and prototyped cable is made of up to 87 tapes of 4 mm width SuperOx tape arranged across the three phases. Our computational results are compared to the experimental measurements performed by VNIIKP with the electrical contact method, showing a high degree of accuracy over the outer phase of the cable, whilst revealing technical issues with the experimental measurements at the inner phases. Thus, in consultation with VNIIKP it has been concluded that for the actual experimental measurement of the AC losses at the inner phases, and consequently of the overall cable, a sophisticated calorimetric setup must be built. Still our model is capable to provide an independent assessment of the VNIIKP-SuperOx cable design, by investigating the magnetic profiles per phase in the time domain. In this sense, we confirm that the unbalanced arrange of currents and distancing between the phases affirmatively lead to no magnetic leakages, and therefore to an adequate balance of the cabling inductance.
Electric Aircraft Fueled by Liquid Hydrogen and Liquefied Natural Gas
Authors: Telikapalli Srikar , Swain Roberto M. , Cheetham Peter , Kim Chul H. , Pamidi Sastry V. 
Published: June 2022

Abstract
The paper is a review of the opportunities and challenges of cryogenic power devices of electric aircraft, and the ongoing research and development efforts of the government agencies and the industry. Liquid Hydrogen (LH2) and Liquefied Natural Gas (LNG) are compared to support high temperature superconducting (HTS) and normal metal devices, respectively. The power devices were assumed to operate at the normal boiling point of the fuel used. The efficiencies of the electrical devices are estimated based on state-of-the-art technology. The mass flow rates and total fuel requirements for both the cryogenic fuels required to maintain the operating temperatures of the devices were simulated using thermal network models. A twin-aisle, 300 passenger aircraft with a 5.5 h flight duration was used for the models. The results show that the required masses of LH2 and LNG are 744 kg and 13,638 kg, respectively for the cooling requirement. The corresponding volumes of LH2 and LNG required are 9,760 and 30,300 L, respectively. In both cases, the estimated mass of the fuel needed for the aircraft is more than what is needed to maintain the cryogenic environment of the power devices. It was concluded that an electric aircraft with LNG cooled normal metal devices is feasible. However, an aircraft with HTS devices and cooled with LH2 is more attractive if the ongoing R&D efforts on HTS devices and LH2 infrastructure are successful. The emission reductions would be substantially higher with LH2, particularly when H2 is produced using renewable energy sources.