bluuebunny/crossref_metadata_2025 huggingface dataset:
Commissioning and cryogenic performance of the UKRI STFC Daresbury Vertical Test Facility for jacketed SRF cavities
Authors: May A J , Pattalwar S , Mason D , Middleman K , Pendleton M D , Smith P A , Wilde S , Akintola A , Bainbridge A , Buckley R , Collier G , Corlett P , Dumbell K , Ellis M , Hancock M , Hathaway J , Hitchen S , Hodgkinson C , Hornickel P , Hughes G , Jenkins C , Jones G , Lowe M , McIntosh P , Miller G , Mutch J , Moss A , Oates A , Pattalwar N , Sollars P , Wheelhouse A E , White A A J , Wilson J
Published: June 2022

A novel vertical test facility has been developed at the STFC Daresbury Laboratory. The cryostat is designed to test 3 jacketed superconducting RF cavities in a horizontal configuration in a single cool-down run at 2 K. The cavities are cooled with superfluid helium filled into their individual helium jackets. This reduces the liquid helium consumption by more than 70% in comparison with the conventional facilities operational elsewhere. The facility has now completed commissioning successfully and moved into a 2-year program to qualify 84 high-beta SRF cavities for the ESS (European Spallation Source) as part of the UK’s in-kind contribution. This paper reports on the commissioning program, along with a detailed discussion of the cryogenic operations and performance of the facility, including that of the cryoplant.
Cryogenic Accelerated Fatigue Tester for additive manufactured polymer composite mechanical property measurement
Authors: Adams R , Hunt M , Leachman J
Published: June 2022

Additive manufacturing (AM) of polymer matrix composite (PMC) materials maintains the potential to significantly reduce part count, weight, and costs for future aerospace development. However, a lack of maturity in loading systems has inhibited the characterization of these materials for the cryogenic environment of space. These PMCs demand lifespan endurance when faced with cryogenic thermal cycling in series with high-frequency mechanical loading. Few mechanical testers have been capable of achieving the cryogenic temperatures and actuating frequency to simulate the environment that a PMC endures in a cryogenic application. Also, these testers have yet to define the tensile and fatigue PMC mechanical behavior at these temperatures. To curate a cryogenic, fatigue profile on PMCs, the Cryogenic Accelerated Fatigue Tester (CRAFT) was developed. CRAFT utilizes a 12-kN load frame in unison with a cryocooler to perform tension-tension and tension-compression fatigue tests up to 100 Hz in a liquid hydrogen environment. This publication reviews the CRAFT design and capabilities. Determining the cryogenic fatigue life of 3D-printed PMCs through testing in CRAFT allows for the validation of proper material implementation and the future optimization of these materials in cryogenic environments.
Cryogenic system upgrade of Fermilab’s IB1 test facility - phase I
Authors: Hansen B J , Al Atassi O , Wang R , Dong J , Soyars B , Richardson D , Theilacker J
Published: June 2022

The IB-1 cryogenic test facility is used for testing and qualifying superconducting components in support of various DOE projects and programs. The facility was identified as the highest priority need for a cryogenic system upgrade, as it currently relies on a 1977 era coldbox that requires increasingly more resources and maintenance downtime to remain operational. The first phase of the facility upgrade includes purchasing a Cryogenic Liquefier (Coldbox) from industry and integrating it into the IB1 facility infrastructure. The integration scope includes the addition of a second Mycom compressor skid, warm interconnecting piping between the Coldbox and compressor system, a cryogenic distribution system to connect the new Coldbox to the existing cryogenic system, and various electrical, controls and support utility upgrades. This paper describes the integrated design of the new IB1 cryoplant, modes of operation and status.
Design and analysis of the helium purification system for the NSRRC cryogenic system
Authors: Chuang P S , Tsai H H , Chiang H W , Hsiao F Z , Liao W R , Li H C , Chiou W S , Chang S H , Wang P J
Published: June 2022

Helium is an expensive consumable in cryogenic facilities and is used widely in space, medical and energy research. At NSRRC, liquid helium is used as a coolant for superconducting magnets and SRF cavities . Minor contaminants such as nitrogen, oxygen, moisture and oil will be picked up when liquid helium circulates in large scale cryogenic systems and such contaminants can crystalize and cause damage to the cold box turbo expanders resulting in system damage and failure . Therefore, a helium purification system is designed as an integral part of the cryogenic system to conserve helium by providing 99.9995% pure helium to the liquefier after eliminating contaminants. The NSRRC helium purification process is based on two principles, the first one being a cryo-sorption device using activated charcoal and a molecular sieve and the other being a cryo-condensation unit using a tubular heat exchanger. The purifier has been designed to purify impure helium with overestimated contaminants of as much as 2.5% nitrogen and 2.5% oxygen with a mass flow rate of 475 nm3/hr and delivering a pressure of 17 bar(a) of impure helium to the purifier, the actual impurity will be much lower than the actual design contaminants. In this paper, calculation and design of the helium purification system and components composed of one double pipe counter flow heat exchanger, one vessel and tube heat exchanger, one pre-cooler and one charcoal vessel will be discussed together with charcoal mass requirement calculations and design of other components. In NSRRC, helium is liquefied and is used as a coolant for the SRF system and for cryogenic undulators. During a cryogenic cycle in the cryogenic system, helium may pick up contaminants such as moisture, oxygen, oil, and nitrogen, which have a higher freezing point than liquid helium and will crystalize. These frozen impurities will then affect plant capacity and operation such as alternating flow characteristics, damaging moving parts like turbines in the cold box causing the overall cooling efficiency to drop. Eliminating the contaminants is therefore very important for the cryogenic system.
Design aspects of the feed boxes of the Super-FRS Local Cryogenics System
Authors: Polinski J , Chadaj D , Chorowski M , Iluk A , Kollmus H , Pachnik L , Simon H , Wamers F , Winkler M , Xiang Y
Published: June 2022

The Super-FRS is an electromagnetic separator and spectrometer designed for the production and selection of highly energetic and intense exotic heavy-ion beams. It is part of the Facility for Antiproton and Ion Research (FAIR) particle accelerator currently under construction at GSI, Darmstadt, Germany. The Super-FRS will feature in total 63 superconducting magnet cryostats: 27 dipoles, 35 multiplets (7 short and 28 long), and the GLAD experiment magnet. The Super-FRS Local Cryogenics will distribute and feed cold helium from the central cryogenic plant “CRYO2” to the magnet cryostats. Daisy-chain like arrays of feed and end boxes are connected via transfer line pieces. Each single magnet cryostat is supplied by one feed box via a jumper connection. The dipole, short- and long multiplets require different helium mass streams at different operation modes. Moreover, the Local Cryogenics system must follow the Super-FRS curvature and irregular pattern of cryostat locations. In order to simplify the production process, lower the risk of technical mistakes, and increase the flexibility of the installation sequence during the conceptual design project phase an effort was made to develop a uniform construction of the feed boxes for all cryostat types. The paper provides the description of the Super-FRS Local Cryogenics system and the process requirements for all cryostat types in all possible operation modes. The Super-FRS feed box flow scheme and features that allow for unification of its design for all cryostat types are also presented.
Sub-atmospheric re-pressurization analysis of FRIB linac segment 2 cryogenic distribution system
Authors: Howard J , Knudsen P , Hasan N , Ganni V
Published: June 2022

The continuous wave heavy ion beam linear accelerator at FRIB consists of 46 cryo-modules, housing 324 superconducting radio-frequency (SRF) resonators and 69 superconducting solenoids. The three linear accelerator (Linac) segments, designated LS1 to LS3, are arranged in the shape of a paper clip, with 4 superconducting dipole magnets in the curved segments. The SRF resonators are operated at 2 K, requiring a sub-atmospheric helium pressure, and the superconducting magnets are operated at 4.5 K. The design of the cryogenic transfer-lines for these Linac segments is complex and contains multiple process lines. Namely, these are the primary (4.5 K) supply, and return, sub-atmospheric return, 35 K shield supply and 55 K shield return. The shield return encloses the other process lines, thermally intercepting the ambient temperature heat load. Testing was conducted on the re-pressurization and liquid levels of the 24 cryo-modules of LS2’s 2 K system. System models were developed and then compared to the test data to characterize the static heat in-leak to the cryo-modules. Reasonable agreement was found between the validated models and preliminary measurements.
Proton Improvement Plan II Cryogenic Distribution System thermodynamic design
Authors: Kumar Shukla Ashish , Dalesandro Andrew , Dhuley Ram , Soyars William
Published: June 2022

The Proton Improvement Plan – II (PIP-II) is a superconducting linear accelerator being built at Fermilab that will provide 800 MeV proton beams for neutrino production. The Linac requires cooling at 40 K, 5 K, and 2 K temperatures, which will be provided by cryogenic helium produced by a Helium Cryoplant and distributed by a Cryogenic Distribution System (CDS). Based primarily on the Linac heat load requirements at each temperature and the allowable pressure drop, we have made a preliminary thermodynamic design of the CDS. The design also incorporates special requirements such as controlled and/or fast cooldown of the superconducting RF cavities and their dual maximum allowable working pressures. This paper presents the overall features of the PIP-II CDS, sizing of helium process circuits, different operating modes, and calculated mass flow capacities that cater to these operating modes.
Conceptual design of cryostat for cryo-cooled 37 elements phased array radar system for space surveillance
Authors: Froehlich A. , Barbri H. , Ben Bekhti-Winkel N. , Grenz O. , Koenig F. , Naumann L. , Putselyk S. , Schneider M. , Tiesing M. , Wirths T.
Published: June 2022

The amount of space debris orbiting the earth is increasing. More than 700 000 objects with critical sizes of more than 1 cm have the potential to cause severe damage to space-based infrastructure. Improving the sensitivity of next generation space surveillance RADARs is necessary for the ability to detect space debris with sizes down to 1 cm. For a successful detection, a key parameter is the signal-to-noise ratio (SNR). Therefore the Fraunhofer Institute for High Frequency Physics and Radar Technique (FHR) analyses cryogenic cooled receivers for space surveillance RADAR systems. In addition to electrical frequency, the requirements of a mechanical design for a large cryo-cooled phased array receiver is challenging. In previous papers, an interim stage 7-element cryogenic receiver with cold antennas was mentioned as well as first studies of a scalable RF unit cell. The present paper shows the prototype and first results of a 37 – element phased array receiver, based on simulations. The design of a cryogenic phased array requires thermal and mechanical simulations in consideration with the modular design concept including the scalable unit cell. Referring to the German Space Surveillance Tracking RADAR (GESTRA) operating in L-band leads to the large receiver size due to the free-air wavelength of 23 cm. This paper presents our approach in the design of a 37 cryogenic phased array. It presents the simulation with focus on thermal transitions, heat loads and mechanical stress.
Thermodynamic analysis of a liquid air energy storage system with off-peak electric heat storage and reutilization
Authors: Fan X , Hu J , Ji W , Guo L , Gao Z , Guo J , Chen L , Wang J
Published: June 2022

As a large-scale energy storage technology, liquid air energy storage (LAES) can effectively improve the stability and quality of power grid. However, the traditional LAES has low cycle efficiency, high initial investment and low economic benefits. In order to improve the system performance, a LAES system based on off-peak electric heat storage and high temperature preheating of turbine inlet air was proposed. The thermodynamic characteristics of the LAES system were analyzed, and the energy analysis, exergy analysis and economic evaluation were carried out. Combined with off-peak electric heat storage, the power generation during the peak time by the LAES system can be significantly increased, and the economy of the LAES system can be effectively improved with the peak-valley electricity price difference, especially in areas where the price difference is obvious. The results will be beneficial for the application and promotion of the LAES technology.
Preliminary analysis and design of 4kW@4.5K helium refrigerator for CFETR toroidal field magnet test facility
Authors: Lu X F , Zhang Q Y , Zhou Z W , Chen A Y , Zhu P , Li S S
Published: June 2022

China Fusion Engineering Test Reactor (CFETR) is the next magnetic confinement fusion device to demonstrate fusion energy. To test the cryogenic performance of CFETR Toroidal Field (TF) superconducting magnet, a large-scale helium cryogenic system was under construction to provide Supercritical Helium (SHe), supported by Comprehensive Research Facility for Fusion Technology (CRAFT). In this paper, heat loads of TF magnet and the dedicated distribution system were analysed to define the scale. Process flow of the helium refrigerator has been designed considering the various operation phases. Preliminary thermodynamic cycle of the helium refrigerator have been calculated with the capacity of 4kW@4.5K+20g/s@50K. This 4kW@4.5K helium refrigerator was not only a test facility for CFETR superconducting magnets, but also a prototype of CFETR helium refrigerator.
LCLS-II warm helium compressor commissioning
Authors: Ravindranath V , Apte A , Fauve E , Heloin V , Pflueckhahn D , Peterson T , Robinson D , Shrishrimal S , Arenius D , Bhattacharya R , Bevins M , Creel J , Hogan J , Norton R
Published: June 2022

LCLS-II is major up-grade to the SLAC Facility. It adds a 4 GeV superconducting accelerator, which will generate an extremely bright and continuous (million pulses/sec) X-ray laser beam. The LCLS-II superconducting accelerator comprises 37 cryomodules connected through a complex distribution system to two large Helium Refrigerators. A single Helium cryogenic plant is expected to deliver 4.0 kW of cooling capacity at 2.0 K. Each cryogenic plant has a set of five operating compressors with an additional spare compressor that provides the required mechanical power (∼ 4.5 MW / cryogenic plant). In this paper, we describe the recent commissioning and performance test results of the LCLS-II compressor system.
LCLS-II helium cryoplant and cryo distribution system installation
Authors: Pflueckhahn D , Fauve E , Heloin V , Kaminski S , Peterson T , Pucci J , Ravindranath V , Sevilla J , Dalesandro² A , Klebaner A , Martinez A , Soyars² W , Arenius D , Bevins M , Hogan J
Published: June 2022

The helium cryoplant and cryo distribution system (CDS) are key elements of the new superconducting Linac Coherent Light Source (LCLS-II) and will provide superfluid helium to the accelerator. The cryoplant consists of two helium refrigerators with an equivalent 4.5 K refrigeration capacity of 18 kW each. The 37 cryomodules of the LINAC will be operated at a temperature of 2.0 K to accelerate a 4 GeV electron beam that will generate extremely bright X-ray laser light. Two five-stage cold compressor cold boxes will be utilized to provide superfluid helium II for the superconducting cavity structures with a total cooling capacity of 8 kW at 2.0 K. This paper describes the installation of the LCLS-II cryoplant and CDS. The LCLS-II cryoplant was designed and contributed by Jefferson Lab. To expedite the project completion the reuse of proven design and technology from the Jefferson Lab CHL-2 cryoplant was the preferred strategy. The CDS consists of ∼260 m thermally shielded and vacuum super insulated transfer lines, two distribution boxes and eight feed and end caps, and was designed and contributed by Fermilab. SLAC installed the cryoplant components into a newly erected building and the CDS components into the existing accelerator tunnel and klystron gallery with strong engineering support from both partner labs.
The development status of Sunpower DS 10 cryocooler
Authors: Kim Yongsu , Collins Josh
Published: June 2022

The CryoTel® MT is an integral Stirling cryocooler with 5 W of lift capacity at 77 K with a nominal input power of 80 W. The MT has the smallest size and cooling capacity among Sunpower’s integral cryocoolers. The contact-free operation of the moving components by using Sunpower’s gas bearings technology results in a long lifetime of the cooler, achieving an MTTF of over 200,000 hrs. Followed by the design and product development efforts of the CryoTel DS 30, Sunpower has been developing another dual opposed piston and split configuration Stirling cryocooler, DS 10, by leveraging the back end of the MT cryocooler. By using as many as existing components and subassemblies from the MT cryocooler, we minimized new component design and development for the wave generator. The cold head is entirely new, but it is a scale-down design of the DS 30 cold head. Relying on the experience and lessons learned from the DS 30, we expect minimal design, development, and troubleshooting efforts in production. The development of the DS 10 wave generator complete and tested with a DS 30 cold head. The test showed 11.8 W of lift at 77 K with an input power of 160 W.
Requirement of the on/off ratio of superconducting heat switch used for the continuous stage of cADR
Authors: Liu Ping , Li Ke , Wang Chang , Yu Fangqiu , Shen Jun , Dai Wei
Published: June 2022

As an important component of the adiabatic demagnetization refrigerator (ADR), the superconducting heat switch uses the different thermal conductivities of a metal in the normal state and the superconducting state to turn the heat switch on / off for the continuous stage. Switch ratio is an important parameter to evaluate the performance of a heat switch, which is related to many factors. Peter Kittel calculated the different switch ratio requirements in the single-stage and multi-stage ADR. Based on that, this paper focuses on the relationship between the required switch ratio and operating parameters of the ADR system, especially the ratio of the heat leak to the effective cooling power.
Cryogenic System Design and Performance Test of Calibration Magnet
Authors: Zhao H , Feng H S , Hu R
Published: June 2022

According to the requirements of high-energy particle accelerators, a cryostat system was designed and manufactured to provide a low-temperature environment for high uniformity superconducting magnet used for calibration. The performance test of the calibration magnet system including linearity, locking area, stability, and uniformity was completed. This system uses a single 1.5 W @ 4.2 K refrigerator by combining direct conduction cooling with indirect conduction cooling of the gravity heat pipe. The superconducting magnet was cooled to 4 K and entered the superconducting state, and the minimum temperature reached 2.8 K within 40 hours. The maximum excitation current is 300 A and the maximum magnetic field reaches about 6.2 T. At present, the equipment has been running stably for more than 90 days.
Numerical analysis of delamination degradation of epoxy-impregnated superconducting coils wound with REBCO tapes caused by thermal stress
Authors: Ohya M
Published: June 2022

REBa2CuOy (REBCO) superconducting wires are expected to be used in coil applications owing to their excellent magnetic field properties. However, their weak delamination strength may deteriorate the superconducting characteristics of an epoxy-impregnated REBCO coil during cooling. In general, degradation is unlikely to occur if the outer-to-inner diameter ratio is less than 1.4; however, degradation has been reported in single pancake coils with an inner diameter of 560 mm and an outer diameter of 670 mm. A thermal stress analysis study is conducted to investigate the cause of this problem. Considering the non-uniformity of the epoxy resin thickness at the top and bottom of the coil, coil warping during cooling is simulated. When an FRP reinforcement plate is attached to the coil to suppress warpage, a high radial stress generated in the coil owing to the thermal contraction difference between the coil and FRP plate. The maximum local radial stress exerting in the delamination direction is 30 MPa, which is believed to degrade the superconducting characteristics of the REBCO single pancake coils.
Effect Analyses of Thermal Deformation on Magnetic Performance of the CPMU Prototype in SSRF
Authors: Wang Jian , Wang Li , Liu Yiyong , Zhang Wei
Published: June 2022

A cryogenic permanent magnet undulator (CPMU) prototype cooled by sub-cooled liquid nitrogen was developed in Shanghai Synchrotron Radiation Facility (SSRF) in 2016. The CPMU prototype mainly consist of NdFeB based hybrid magnet arrays with a period of 20 mm and a magnetic length of 1.6 m, a pair of girders to support the magnetic arrays, parallel SLN2 cooling loops attached to the girders, thermal spacers connecting the girders and the copper LN2 tubes, electric heaters to heat the girders and regulate the magnet working temperature at around 120 K, and stems made of stainless steel to support the girders. During the first magnetic field measurement, the RMS phase error of the CPMU prototype changed from 3.2 degree at room temperature to 4.5 degree at 135 K. By shimming the magnetic field, its RMS phase error is reduced to 3.5 at low temperature finally. This paper presents detailed analyses of temperature distribution and thermal deformation along the CPMU girder during cool down process. By comparison with test results, the deterioration of the RMS phase error is well explained. The analyses can provide guidance for magnetic field shimming and avoid or reduce the deterioration of the RMS phase error at low temperature.
Study on Irradiation Effect of Insulating Materials for Fusion Superconducting Magnet: Effect of Low-temperature Irradiation
Authors: Kunitoku Y , Akiyama Y , Manabe Y , Sato F
Published: June 2022

The purpose of this study is to investigate the change in dielectric performance in the direction of parallel to layers due to the difference in γ-ray irradiation temperature, irradiation atmosphere, and absorbed dose. γ-ray was irradiated using a 60Co source at room temperature, in liquid nitrogen, and in liquid nitrogen temperature gas atmosphere in the absorbed doses of 0, 5, and 10 MGy, respectively, and the dielectric breakdown tests were conducted at room temperature using a high-voltage breakdown tester. To investigate the mechanism of the change in dielectric strength, the density and electron spin resonance (ESR) measurements of the specimens were carried out. After irradiation at room temperature, the dielectric strength increased slightly with the increase in the absorbed dose. The reason for this may be that the molecular density increased due to the promotion of cross-linking reaction by recombination of molecules and reaction of unreacted epoxy groups by γ-ray irradiation. After irradiation in liquid nitrogen, the dielectric strength decreased significantly at 10 MGy, while after irradiation in liquid nitrogen temperature gas atmosphere, the dielectric strength slightly decreased with the increase in absorbed dose. These results suggest that, at low temperature, the freezing of molecular motion limits the movement of radicals generated by irradiation, and that the decomposition reaction is dominant against the crosslinking reaction.
Interlaminar shear strength of vacuum pressure impregnated coils with epoxy resin for high field magnet at cryogenic temperature
Authors: Wang Chundong , Zhao Yalin , Liu Huiming , Fang Zhichun , Xin Jijun , Wu Zhixiong , Huang Chuanjun , Huang Rongjin , Li Laifeng
Published: June 2022

The interlaminar shear properties of epoxy impregnated coils are critical parameter to the design of the high field superconducting magnets. The existing test methods of the interlaminar shear strength of the composite insulation systems for the superconducting magnet coils in cryogenic temperature were discussed. The insulation system of the niobium titanium superconductor coated with woven glass fiber reinforced polymer coil were fabricated by vacuum pressure impregnation with IR-3 and CTD-101K resins. Short beam shear tests of the impregnated coil were performed at room temperature and liquid nitrogen temperature (77K). The results show that the interlaminar shear strength of the samples used IR-3 resin are better than CTD-101K both at room and cryogenic temperature. A detailed observation of the failed specimens was also investigated to verify the failure mechanisms by optical microscopy.
Numerical simulation and experimental investigation of the thermal insulation performance of multi-layer insulation material at 20-298 K
Authors: Zhao Y C , Li X , Shen F Z , Zhang H C , Li L F
Published: June 2022

Thermal insulation plays a major role in the use of cryogenic systems. Due to its superior thermal insulation property, Multi-layer insulation materials (MLI) are widely used in various cryogenic systems, such as superconducting magnets, space propellant storage, satellites and so on. Thus, it is crucial to estimate and measure the insulation performance of it. This paper has carried out a numerical simulation of the performance of one kind of MLI through a modified Layer-by-Layer model. The thermal insulation propriety of the test specimen is also measured by a newly designed measurement system, which is based on the steady-state axial heat flux method. Finally, the simulation and test results are compared and discussed.
Interface Engineering for Enhanced Magnetic Vortex Pinning by 1D-BZO APCs in a Wide Angular Range
Authors: Ogunjimi Victor , Sebastian Mary Ann , Zhang Di , Gautam Bibek , Jian Jie , Huang Jijie , Zhang Yifan , Haugan Timothy , Wang Haiyan , Wu Judy
Published: June 2022

Microstructural analysis of the BaZrO3(BZO)/YBa2Cu3O7(YBCO) interface has revealed a highly defective and oxygen deficient 2-3 nm thick YBCO column surrounding the BZO one-dimensional artificial pinning centers (1D-APCs). The resulting semi-coherent interface is the consequence of the ∼7.7% BZO/YBCO lattice mismatch and is responsible for the low pinning efficiency of BZO 1D-APCs. Herein, we report an interface engineering approach of dynamic Ca/Cu replacement on YBCO lattice to reduce/eliminate the BZO/YBCO lattice mismatch for improved pinning at a wide angular range of the magnetic field orientation. The Ca/Cu replacement induces a local elongation of the YBCO c-lattice near the BZO/YBCO interface, thereby ensuring a reduction in the BZO/YBCO lattice mismatch to ∼1.4% and a coherent BZO/YBCO interface. This has resulted in enhanced pinning at B//c-axis and a broad angular range of B-field orientation. For example, the 6 vol.% BZO/YBCO film with interface engineering exhibitsFp∼158 GN/m3at 65 K and B//c-axis, which is 440% higher than the ∼36.1 GN/m3for the reference 6% BZO/YBCO sample, and enhancedJcandFpin a wide angular range up to ∼ 80°. This result illustrates a facile scheme for engineering 1D-APC/YBCO interface to resume the pristine pinning efficiency of the 1D-APCs.
Low cost, simpler HTS cable conductors for fusion energy systems
Authors: Zhai Y , Otto A , Zarnstorff M
Published: June 2022

The cost and complexity of large, high-field superconducting magnet modules and related subsystems comprise 30% to 60% of the fusion reactor core capital cost. The strategic plan for the U.S. burning plasma research, the Fusion Energy Sciences Committee Report (FESAC) “Power the Future: Fusion and Plasmas’', and 2021 NASEM report “Key Goals and Innovations needed for a U.S. Fusion Pilot Plant” recommends that the U.S. pursue innovative science and technology to enable construction of a Fusion Pilot Plant (FPP) that produces net electricity from fusion at reduced capital cost. To achieve this, a novel combination of lower-cost high temperature superconductors (HTS) in cable configurations with co-wound reinforcement for higher current density are being investigated using a simplified construction strategy to produce compact stable coils. They would be capable of generating 20 T at up to 10-20 K. Small-scale, inexpensive test coils and prototypes will help develop each feature and validate cabled conductor design models. The near term goal is to validate engineering approaches, scientific models and fabrication capabilities applicable to fusion reactor development such as U.S. fusion nuclear science facility (FNSF), sustained high-power density tokamak facility (SHPD) and FPP designs. The design options include lower-cost, high-strength, quench resistant REBCO or Bi-2212 cables in an all metal coil design that simplifies HTS coil construction and quench protection system, with co-wound reinforcements that integrate stress management in HTS cable design and provides thermal mass to help prevent quench damage.
Superconducting liquid cryogen insulated power cables for medium voltage applications
Authors: Lopez H , Mensah P , Cheetham P , Kim C H , Pamidi S
Published: June 2022

Liquid Nitrogen (LN2) is used as the cryogen and is part of the dielectric insulation system in most high temperature superconducting (HTS) power cables. However, in electric propulsion systems for transportation, using LN2 is not feasible due to asphyxiation concerns in the event of a leak in a confined space. Gaseous helium (GHe) has been proposed as an alternate cryogen to relieve this asphyxiation concern. GHe has benefits such as a wider operating temperature range and versatility for a centralized cryogenic cooling system for multiple devices which could potentially reduce the overall weight of the superconducting system. The drawback is that GHe has a lower dielectric strength compared to LN2, which limits its use to low-medium voltage applications. A hybrid cryogen HTS cable was proposed using LN2 as the dielectric media and GHe as the cryogen of an HTS cable to solve the limitations and issues associated with each cryogen and explained in this paper. A 1-m prototype cable that used LN2 as the cryogen and dielectric was fabricated and dielectric breakdown measurements were performed on it to establish a baseline on what to be expected from the hybrid cryogen HTS cable.
Design of warm dielectric terminations and electrical breaks for high-temperature superconducting power cables
Authors: Mensah P , Lopez H , Cheetham P , Kim C H , Pamidi S
Published: June 2022

Large electric transportation systems such as electric aircraft and electric ships have been designed with multiple high temperature superconducting (HTS) power cables as part of superconducting power distribution network, and a good electric insulation for the power cables is a critical design requirement needed to be considered. This is because terminations in HTS cable represent a location of significant electrical and thermal stresses and needs to be addressed to reduce the substantial heat load that might be introduced into the cryogenic system. The use of a warm dielectric termination is seen as a potential solution to reduce the electrical standoffs required as part of the design and allow for a high-power dense termination design. A warm dielectric termination design using commercially off-the-shelf ceramic breaks as electrical breaks is explored and withstand and partial discharge measurements are performed to determine the viability of the design concept.
Strategies for conformal REBCO windings
Authors: Rogers J S , McIntyre P M , Elliott T , May G D , Ratcliff C T
Published: June 2022

A high-field winding can be fabricated from a cable of non-insulated REBCO tapes stacked face-to-face without twisting. If the cable is oriented within each turn of a winding so that the tape face is closely parallel to the magnetic field at its location, the supercurrent capacity of that cable is enhanced ∼3x greater than in a transverse or twisting orientation. This concept for a conformal winding was presented in a previous paper pertinent to the body winding of a REBCO based high-field dipole. Strategies are presented and simulated for how the same orientation can be sustained in the flared ends of a high-field hybrid dipole.
Structural Finite Element Analysis of REBCO Tape Delamination with Solid-Shell Element under Various Loads
Authors: Zhao Zijia , Moore Peter , Chiesa Luisa
Published: June 2022

Structural Finite Element Analysis was performed to study the delamination behaviour of layer laminated REBCO tapes using a Solid-Shell element under various loading conditions, including (1) transverse tensile delamination, (2) shear delamination and (3) peeling delamination. A Solid-Shell element is well suited to simulate REBCO tape because the material and thickness of all the layers can be specified within a single element. The results obtained from the models utilizing Solid-Shell elements are compared to a more computationally intensive method known as Cohesive Zone Method (CZM), which has successfully modelled the initiation and propagation of REBCO’s delamination [1]. The results show that the stress state of REBCO tape in transverse tensile and shear directions can be accurately captured by the proposed method employing Solid-Shell elements if the transverse tensile and shear delamination stress is measured experimentally for a specific REBCO and used as failure criteria. In this work, the failure criteria adopted from previous experimental studies are 50 MPa in the transverse tensile direction and 10 MPa in the shear direction. This work provides a time-efficient modelling tool to predict and mitigate delamination in REBCO tapes used in complex systems.
First cryogenic test results of 3D-printed resonators for quantum bits
Authors: Carriere P R , Frigola P , Agustsson R , Chou M H , Cleland A N , Horn T , Kelly M , Kutsaev S V , Povey R , Smirnov A Y
Published: June 2022

Quantum computers (QC) have the potential to efficiently solve problems currently unfeasible on even the fastest generation of classical computers. The building block of a QC is a quantum bit (qubit). Encoding and reading qubit states coupled via high-Q resonant cavity modes is a solution to maintaining qubit states; however there is a need for simple, scalable and robust fabrication techniques capable of realizing high density cavity arrays. RadiaBeam is developing a novel approach utilizing metal additive manufacturing(AM) using both laser and electron beam powder bed fusion. Using a 6GHz quarter wave resonator (QWR), we fabricated several niobium and titanium alloy QWR cavities and characterized their superconducting RF performance. In this letter, we provide the details of the first 3D-printed qubit cavities design and fabrication, and compare their Q-factors, measured at dilution fridge temperatures, against the machined Nb resonators.
Cryogenic material properties of additive manufactured 316L stainless steel
Authors: Weiss K-P , Hetzler S , Kvackaj T , Bidulsky R , Actis Grande M , Manfredi D
Published: June 2022

Additive manufacturing is recognized as a potential technology to design and create complex geometries as well as a fast track to build prototype components. Different materials are possible to use, depending on the specific requirements of an application. Superconducting applications like magnets or rotating machines are demanding for the structural components. Either high and/or cyclic mechanical loads can be one of the limiting factors in design. In the cryogenic temperature regime austenitic steels are used due to the mechanical performance and the machinability. In this work 316L austenitic steel samples were produced using laser powder bed fusion, also known as Selective Laser Melting (SLM). Followed by different heat treatments to systematically influence to the microstructure evolution. Beside mechanical properties also thermal properties as heat capacity or expansion are investigated. Having the cryogenic application in mind the tests are conducted at room temperature, liquid Nitrogen and liquid Helium temperature. The measured mechanical and thermal properties are compared to industrial cast austenitic steels to qualify the overall performance of the additive manufactured samples.
A review of devices and methods for measuring thermal emissivity at cryogenic temperatures
Authors: Zhang S Y , Li Y , Li L F
Published: June 2022

Thermal emissivity is an important parameter in characterizing the thermal radiative properties of materials and a critical factor in radiative heat transfer. The radiation of an actual object is different from that of the blackbody: its radiation energy varies irregularly with wavelength and temperature. To investigate the thermal radiative properties, thermal emissivity could be measured at cryogenic temperatures. In this paper, measuring methods and factors affecting the thermal emissivity of metals and infrared coatings at low temperatures were comprehensively reviewed. Two existing methods for measuring thermal emissivity at low temperatures, the calorimetry and radiometry methods, were described. Moreover, this work also discussed several factors such as material properties, surface temperature, and surface conditions. Testing devices for measurement of emissivity at low temperatures based on calorimetry and radiometry were reviewed and analyzed emphatically.
A new research agenda for Africa’s international relations
Authors: Tieku Thomas Kwasi
Published: June 2022

The article takes stock of the eclectic Africa’s International Relations (AIR) scholarship with a view to setting a new research agenda for this vibrant subfield of International Relations (IR). It argues that the AIR community has taken a defensive approach to knowledge production and dissemination. It calls on AIR scholars to shift the emphasis from reactionary scholarship to an offensive knowledge production and dissemination by building research around five key themes. The article shows that a research agenda in the five areas can give epistemic freedom to AIR scholars, contribute to freeing IR from Euro-American metanarratives, and ultimately put AIR scholars in a position to develop analytical frameworks capable of capturing nuances and complexities of international life in Africa.
Violence in the Great Recession
Authors: Santaularia N Jeanie , Osypuk Theresa L , Ramirez Marizen R , Mason Susan M
Published: June 2022

Substantial evidence suggests that economic hardship causes violence. However, a large majority of this research relies on observational studies that use traditional violence surveillance systems that suffer from selection bias and over-represent vulnerable populations, such as people of color. To overcome limitations of prior work, we employed a quasi-experimental design to assess the impact of the Great Recession on explicit violence diagnoses (injuries identified to be caused by a violent event) and proxy violence diagnoses (injuries highly correlated with violence) for child maltreatment, intimate partner violence, elder abuse, and their combination. We used Minnesota hospital data (2004–2014), conducting a difference-in-differences analysis at the county level (n = 86) using linear regression to compare changes in violence rates from before the recession (2004–2007) to after the recession (2008–2014) in counties most affected by the recession, versus changes over the same time period in counties less affected by the recession. The findings suggested that the Great Recession had little or no impact on explicitly identified violence; however, it affected proxy-identified violence. Counties that were more highly affected by the Great Recession saw a greater increase in the average rate of proxy-identified child abuse, elder abuse, intimate partner violence, and combined violence when compared with less-affected counties.
Prevalence of Loneliness and Its Association With General and Health-Related Measures of Subjective Well-Being in a Longitudinal Bicultural Cohort of Older Adults in Advanced Age Living in New Zealand: LiLACS NZ
Authors: Lay-Yee Roy , Milne Barry J , Wright-St Clair Valerie A , Broad Joanna , Wilkinson Tim , Connolly Martin , Teh Ruth , Hayman Karen , Muru-Lanning Marama , Kerse Ngaire
Published: June 2022

Objectives

There is evidence that loneliness is detrimental to the subjective well-being of older adults. However, little is known on this topic for the cohort of those in advanced age (80 years or older), which today is the fastest-growing age group in the New Zealand population. We examined the relationships between loneliness and selected subjective well-being outcomes over 5 years.

Methods

We used a regional, bicultural sample of those in advanced age from 2010 to 2015 (Life and Living in Advanced Age: a Cohort Study in New Zealand). The first wave enrolled 937 people (92% of whom were living in the community): 421 Māori (Indigenous New Zealanders aged 80–90 years) and 516 non-Māori aged 85 years. We applied standard regression techniques to baseline data and mixed-effects models to longitudinal data, while adjusting for sociodemographic factors.

Results

For both Māori and non-Māori, strong negative associations between loneliness and subjective well-being were found at baseline. In longitudinal analyses, we found that loneliness was negatively associated with life satisfaction as well as with mental health-related quality of life.

Discussion

Our findings of adverse impacts on subjective well-being corroborate other evidence, highlighting loneliness as a prime candidate for intervention—appropriate to cultural context—to improve well-being for adults in advanced age.
Aging With Incarceration Histories: An Intersectional Examination of Incarceration and Health Outcomes Among Older Adults
Authors: Latham-Mintus Kenzie , Deck Monica M , Nelson Elizabeth
Published: June 2022

Objectives

Experiences with incarceration are linked to poor mental and physical health across the life course. The purpose of this research is to examine whether incarceration histories are associated with worse physical and mental health among older adults. We apply an intersectionality framework and consider how the intersection of sexism and racism leads to unequal health outcomes following incarceration among women and people of color.

Methods

We employ 2 measures of health (i.e., number of depressive symptoms and physical limitations) to broadly capture mental and physical health. Using data from Waves 11 and 12 of the Health and Retirement Study, we estimated a series of general linear models to analyze differences in health by incarceration history, gender/sex, and race/ethnicity.

Results

Findings suggest that experiences with incarceration are associated with a greater number of physical limitations and more depressive symptoms among older men and women, net of sociodemographic characteristics, early-life conditions, and lifetime stressful events. Formerly incarcerated women, particularly women of color, had more physical limitations and depressive symptoms relative to other groups.

Discussion

These findings suggest that incarceration histories have far-reaching health implications. Older women of color with incarceration histories experience markedly high levels of physical limitations and depressive symptoms in later life.
The Role of Appendicectomy in Ulcerative Colitis: Systematic Review and Meta-Analysis
Authors: Welsh Silje , Sam Zihao , Seenan John Paul , Nicholson Gary A
Published: June 2022

Background

This updated systematic review and meta-analysis investigates the putative role of the appendix in ulcerative colitis as a therapeutic target.

Methods

Ovid Medline, Embase, PubMed and CENTRAL were searched with MeSH terms (“appendectomy” OR “appendicitis” OR “appendix”) AND (“colitis, ulcerative”) through October 2020, producing 1469 references. Thirty studies, including 118 733 patients, were included for qualitative synthesis and 11 for quantitative synthesis. Subgroup analysis was performed on timing of appendicectomy. Results are expressed as odds ratio (OR) with 95% confidence intervals (CIs).

Results

Appendicectomy before UC diagnosis reduces the risk of future colectomy (OR, 0.76; 95% CI, 0.65-0.89; I2 = 5%; P = .0009). Corresponding increased risk of colorectal cancer and high-grade dysplasia are identified (OR, 2.27; 95% CI, 1.11-4.66; P = .02). Significance is lost when appendicectomy is performed after disease onset. Appendicectomy does not affect hospital admission rates (OR, 0.87; 95% CI, 0.68-1.12; I2 = 93%; P = .27), steroid use (OR, 1.08; 95% CI, 0.78-1.49; I2 = 36%; P = .64), immunomodulator use (OR, 1.04; 95% CI, 0.76-1.42; I2 = 19%; P = .79), or biological therapy use (OR, 0.76; 95% CI, 0.44-1.30; I2 = 0%; P = .32). Disease extent and risk of proximal progression are unaffected by appendicectomy. The majority (71% to 100%) of patients with refractory UC avoid colectomy following therapeutic appendicectomy at 3-year follow-up.

Conclusions

Prior appendicectomy reduces risk of future colectomy. A reciprocal increased risk of CRC/HGD may be due to prolonged exposure to subclinical colonic inflammation. The results warrant further research, as consideration may be put toward incorporating a history of appendicectomy into IBD surveillance guidelines. A potential role for therapeutic appendicectomy in refractory left-sided UC is also identified.
Lamb waves in elastic–plastic plate containing voids
Authors: Kumar Suraj , Tomar S K
Published: June 2022

Propagation of Lamb waves has been studied in an infinite plate of finite thickness and composed of elastic–plastic material containing void pores. The plastic deformation in the plate material is considered through a single-plane and direction. Assuming a linear relation between the elastic and plastic parts of the change in void volume fraction and using the stress-free boundary surfaces of the plate, the dispersion relations corresponding to the symmetric and antisymmetric vibrations with respect to the mid-plane of the plate are derived. The corresponding dispersion relations of Lamb modes in the elastic–plastic plate have been reduced by neglecting the presence of voids. Some earlier known results are recovered from the present formulation under particular cases. The behaviour of symmetric and antisymmetric family of Lamb modes are depicted pictorially against the frequency, slip-angle, thickness of the plate and void parameters in a specific plate material. It is found that the plasticity and the presence of the voids in the plate material affect the propagation of Lamb modes. In particular, at the slip-angle $45^o$, the $S_0$- and $A_0$- modes exhibit symmetry, but $S_0$ is bell shaped and $A_0$ is parabolic.