bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultimate Tensile Strengths and Elastic Moduli at 20 K of Additively Manufactured PA840-GSL, A6061-RAM2, and AlSi10Mg
Authors: Adams R , Rinauro G , Leachman J 
Published: July 2024

Abstract
The additive manufacturing (AM) of polymer matrix composites (PMCs) and metal matrix composites (MMC) systems presents novel opportunities for reducing the mass of aerospace vehicles. These solutions also have the potential to reduce the cost of terrestrial applications where cryogenic temperatures are present. To address this need, this paper explores the mechanical characterization of three AM materials at 20 K: a nylon-based PMC PA840-GSL, and two aluminum-based MMCs A6061-RAM2 and AlSi10Mg. A Cryogenic Accelerated Fatigue Tester (CRAFT) used for the mechanical testing is first detailed. Next, ultimate tensile strengths and elastic moduli of the additively manufactured AlSi10Mg alloy and A6061-RAM2 are obtained. Third, the mechanical performance of an additively manufactured PMC liquid hydrogen tank constituent is collected in addition to an analysis on the effect the processing parameters, such as scan spacing, have on the mechanical behavior. A6061-RAM2 exhibited superior mechanical performance and is recommended for structural applications. Variation of PA840-GSL scan spacing resulted in decreased mechanical performance.
Thermal conductivity and mechanical properties of polymeric aerogels for cryogenic insulation applications
Authors: Churu G , Demko J A , Kimminau K , Lantz D , McGuire H , Van der Weil G , Field M , Malakooti S , Vivod S L 
Published: July 2024

Abstract
Non-vacuum insulation systems are frequently applied in the thermal management of low temperature systems as well as for the use and storage of cryogens. Aerogels are known for their low density, high mesoporosity, high surface areas, low thermal conductivity and high acoustic impedance. This study focuses on polymeric aerogels that can be mass produced as large monoliths while maintaining the low thermal conductivity over a wide temperature range. The manufacturing flexibility of polymeric aerogels allows fabrication of monolithic blocks and sheets that can be applied in various configurations to insulate cryogenic and superconducting devices. To measure the thermal conductivity, an immersion calorimeter was developed and has been operated at different cold boundary temperatures. The calorimeter heats a hollow cylinder of insulating material on the inside surface and the surrounding bath maintains a cold boundary. This calorimeter was used to measure the thermal conductivity of commercially available FoamGlass and a hollow cylinder of a polymeric aerogel machined from a cast cylinder. The thermal conductivity of the FoamGlass and the polymeric aerogel are compared at room temperature (290 K), ice bath (273 K), and at liquid nitrogen (80 K) cold boundary temperatures. Room temperature measurements of the modulus of elasticity and yield strength using an optical technique are also reported for flat specimens of the aerogel made from the same stock as the cylindrical specimens tested for thermal conductivity. Mechanical properties of aerogels are also reported under compression and both at room temperature and at cryogenic temperature (Liquid nitrogen).
Ca-repaired BaZrO3 nanorods/YBa2Cu3O7-x interface for enhanced pinning in YBa2Cu3O7-x nanocomposites with 2-8% BaZrO3 doping
Authors: Wu Judy , Panth Mohan , Ogunjimi Victor , Ann Sebastian Mary , Zhang Di , Haugan Timothy , Wang Haiyan 
Published: July 2024

Abstract
C-axis aligned BaZrO3 (BZO) nanorods formed via strain-mediated self-assembly in BZO-doped YaBa2Cu3O7-x (BZO/YBCO) nanocomposite films can provide strong pinning to the quantized magnetic vortices. While the strain initiated from the BZO/YBCO lattice mismatch plays a critical role in nucleation and evolution of the BZO nanorods, it also leads to a highly defective BZO/YBCO interface and hence reduced pinning efficiency of BZO nanorods. This work reports a recent study in probing the effect of BZO/YBCO interface on the pinning efficiency of the BZO nanorods as the interface is repaired dynamically during the BZO nanorod growth using Ca doping. Within the BZO doping range of 2-8 vol.%, significantly enhanced pinning efficiency of the BZO nanorods have been observed. A peak enhancement up to five-fold of critical current density at 9.0 T and 65-77 K has been obtained in the 6 vol.% BZO/YBCO nanocomposites after the interface repair. This result not only illustrates the critical importance of the BZO/YBCO interface in the pinning efficiency, but also provides a facile scheme to achieve such an interface to restore the pristine pinning efficiency of the BZO nanorods.
Qualification and test of space compatible superconducting current leads (REBCO) designed for adiabatic demagnetization refrigerators
Authors: Duval J M , Prouvé T , Collier-Wright M , Drechsler A , Hindley D , La Rosa Betancourt M , Kroll R , Branco M , Orgaz Diaz D , Schlachter S I 
Published: July 2024

Abstract
Many astrophysics observations require space telescopes, either to reduce atmospheric perturbation or simply to make these detections possible (in the X-Ray spectrum for example). One of these missions, Athena, is led by the European Space Agency (ESA), with additional international contributions, dedicated to X-Ray observation. Two instruments will be part of this mission and among them, X-IFU, will use Transition Edge Sensors (TES) to detect and precisely measure the energy of X-Ray photons. These sensors require a temperature of 50 mK to reach their ambitious sensitivity goals. In space, this temperature can be reached using Adiabatic Demagnetization Refrigeration (ADR) and such a cooling system is currently being developed for the X-IFU instrument. ADR utilizes magnetocaloric materials which, upon variation in magnetic fields, can produce a cooling effect. The magnetic field of the order of 1 T in a volume of 10s of cm3 is produced by a superconducting coil with high winding number and current limited to approximately 2 A. Even though this current is low compared to most earth-based systems, metallic current leads to link the high- and low-temperature stages would cause high thermal loads, unacceptable for the limited capacity of the cryogenic cooling chain of the spacecraft. Therefore, a harness consisting of superconducting current leads is planned to reduce the thermal loads at the low-temperature stage. As part of an ESA contract, our team designed, built and tested such a space-compatible harness. This harness includes the electrical interfaces at both ends as well as mechanical support. Its development is capable of operating between interfaces at 80 K and 4 K. The harness is based on industrially available Rare-Earth-Barium-Copper-Oxide (REBCO) High-Temperature Superconductor (HTS) tapes. The tapes were laser-cut by our group to fulfill our specifications, Parylene coated and reinforced with Kapton laminate tape for mechanical and insulating purposes. After characterization of the single tapes, the assembled harness has been subjected to an extensive qualification sequence including thermal cycling and mechanical testing based on launch loads requirements. This paper will summarize the technical design choices for this HTS harness. It will discuss the test results and propose some perspectives for the next iteration of the development.
Critical current stability of 2G REBCO tape for space-flight HTS leads
Authors: Canavan Edgar R , Comber Brian 
Published: July 2024

Abstract
High reliability is an essential requirement for all spaceflight hardware. Like the Hitomi x-ray observatory, its follow-on mission XRISM uses 2G REBCO tapes as current leads for the superconducting magnets that are a key component of the Adiabatic Demagnetization Refrigerator (ADR) that cools the detector array. While the Hitomi Soft X-ray Spectrometer (SXS) worked flawlessly in orbit, during its development there were indications that the critical current of its specialized REBCO tapes could degrade over time when exposed to normal-humidity air. To demonstrate that the updates to the XRISM HTS lead assemblies had mitigated this risk, a series of tests were carried out to measure the stability of Ic
of dozens of samples over a period greater than the flight assemblies were exposed to air during integration and test. The test rig allowed not only the measurement of the sample Ic
, but also the localization of the voltage rise as the current approached Ic
. We will discuss the trends in the critical current of the samples, as well as localization of lower Ic
regions.
Space experiments using superconducting magnet technology
Authors: Werfel F N , Floegel-Delor U , Riedel T , Schirrmeister P , Koenig R , Kantarbar V , Vakaliuk O 
Published: July 2024

Abstract
We report on a fast-track experiment on the International Space Station (ISS) with the Earth’s magnetic field, which has been recognized as a major task for a better understanding of our planet. For this purpose, YBCO bulk superconductors have been prepared, transported and stored on board the ISS. The properties of single grain superconducting bulk will be investigated before and after the ISS experiments. In parallel, the magnetic interaction between BEarth and our YBCO bulk was investigated. An external 3D Helmholtz coil cancels unwanted electromagnetic fields down to 5 μT. Highly sensitive flux-gate sensors monitored the magnetic configuration as the ceramic plate was cooled to cryogenic temperatures. Shielding and field concentration effects of the Earth’s magnetic field were observed and discussed. Thermally induced magnetic flux compression for future long-duration space missions was successfully tested, enabling future spacecraft shielding and braking functions.
Cryogenic vacuum chamber testing of a conductively-cooled, high temperature superconducting rotor for a 1.4 MW electric machine for aeronautics applications
Authors: Scheidler Justin J. , Stalcup Erik J. , Tallerico Thomas F. , Torres William , Duffy Kirsten P. , Mulder Tysen T. 
Published: July 2024

Abstract
This paper presents the second ever demonstration of a superconducting rotor cooled only via conductive connection to a cryocooler, i.e., without pumped or solid cryogens. The full-scale rotor was operated statically in its intended environment – about 1e-3 torr vacuum with only conductive cooling through mechanical connections to a cryocooler contained on the rotor. Stable operation of the rotor in a representative magnetic environment was demonstrated up to its rated direct current (57.2 A) and the designed temperature limit for the superconductor (62 K). Additional electrical measurements increased confidence that the superconducting coils functioned as intended. A collection of steady state temperature distributions was measured at operating and non-operating conditions. In all but one case, the observed temperature gradient between the cold tip and superconducting coils satisfies the design but with little margin. Opportunities to reduce the gradient are identified.
Preliminary experimental studies into the storage capacity of cryogenic hydrogen in aerogel blanket materials
Authors: Swanger A M , Khlyapov Y , Bone J , Fernandez E , Otto M , Schmitt J , Blair R , Notardonato W U , Kapat J 
Published: July 2024

Abstract
The abundance and diversity of hydrogen applications necessitates continued and accelerated research into advanced storage technologies. Traditionally, hydrogen has been stored as either a high-pressure, warm gas; or a low-pressure, cryogenic liquid. Methods such as cryo-supercritical and cryo-adsorbed have been explored, but are not yet mainstream. Cryo-adsorbed is attractive because higher storage densities at higher temperatures than liquid may be achieved. Recently NASA, in partnership with Eta Space, Southwest Research Institute, the University of Central Florida, and Air Liquide, have been exploring the use of inexpensive, commercially available silica aerogel blanket materials for cryo-adsorbed hydrogen storage. Unlike most adsorbents, aerogel blanket is not a powder, but a robust, composite material that can be formed into complex shapes to aid in more efficient storage system designs, and has already been proven to uptake large quantities of fluids such as nitrogen and oxygen. Recent experimental efforts into the uptake of low-pressure hydrogen gas at 77 K, and liquid hydrogen at normal boiling point (NBP) will be discussed. Although preliminary in nature, the test results are promising, showing up to a 49% increase in storage density at 77 K over the gas alone, and greater than a one-to-one volume equivalency with NBP LH2.
Liquid hydrogen storage and transfer-control system for integrated zero emission aviation (IZEA)
Authors:   Collaboration, Virdi P S , Guo W , Cattafesta L , Cheetham P , Cooley L , Gladin J , He J , Ionel D M , Kim C , Li H , Ordonez J , Pamidi S , Zheng J 
Published: July 2024

Abstract
The growth in the aviation sector has highlighted the need to decrease carbon emissions, a significant factor in climate change. Hydrogen is a potential alternative clean fuel due to its high energy density. As a collaborative effort in developing integrated zero emission aviation (IZEA, a NASA ULI), we present the design concept for a liquid hydrogen storage system for short-range aircraft with a gravimetric index greater than 0.6. Our design leverages the cryogenic cooling power of liquid hydrogen to support the temperature and heat loads of various power system components, such as the high-temperature superconducting (HTS) generator, HTS motor, DC power distribution cable network, and power electronic converters. By controlling the pressure in the storage tank, we demonstrate that it is feasible to deliver the desired mass flow rate of hydrogen while effectively cooling the power system components using practical heat exchangers. Also, since heat exchangers are an integral part of our hydrogen storage and flow system, their design also impacts the overall system storage density. The entire system is designed considering the space and weight factors of an aircraft. This work represents a significant advancement towards developing the complete IZEA thermal management system for a given airplane and flight profile.
Can process intensification of liquefaction technology for LNG and LH2 accelerate adoption for transportation use?
Authors: Barclay J A , Archipley C C 
Published: July 2024

Abstract
One of the reasons gaseous fuels, methane, and hydrogen, are renewable and sustainable replacements for traditional liquid hydrocarbon-based transportation fuels is their small carbon footprint. Global awareness of the immediate need to address impacts of emissions from transportation energy use has emphasized urgency of changes from business as usual. However, the transition from existing fuels to new fuels is complex because fuel usage is huge, and so many variables influence the rate of adoption. When one reads excellent energy outlooks of major energy companies, data driven reports of international and national energy agencies, along with thoughtful studies of the water, energy, food nexus, the systemic complexities are daunting. Marchetti’s insightful numerical modeling of the rate of transition among different energy sources over the past two centuries with credible validation from recorded usage data shows the time scale for appreciable changes among energy systems is several decades. A further important observation of Marchetti’s work is that transitions among energy sources were and are driven by substitution of superior technology rather than by depletion of prevalent sources. These observations incentivize developments of more efficient, less expensive, robust, scalable methods of production, liquefaction, storage, transport, delivery, and dispensing of hydrogen and natural gas to accelerate adoption by transportation customers. This paper presents a few examples of process intensification in advanced liquefiers for LNG and LH2 at the same location could reduce capital costs, energy costs, and footprints of different sized liquefiers. These combinations could help address gaps in existing technology for several essential needs such as liquefiers for heavy-duty vehicle refueling stations or marine vessel bunkering systems, or refrigerators for storage tank boil-off management systems. Modular, containerized liquefiers plants with several tonne/day capacity could be scaled by interconnecting multiple units to make small industrial plants that match localized fuel demands from distributed mobile users.
GaN HEMT and Air Core Magnetics based Power Converters Evaluations at Cryogenic Temperature
Authors: Wei Yuqi , Maksudul Hossain Md , Alan Mantooth H. 
Published: July 2024

Abstract
Cryogenic power electronics is both advantageous and indispensable in many applications, like deep space probe, military electric vehicle, magnetic resonance imaging etc. Among different semiconductors, the gallium nitride (GaN) high electron mobility transistor (HEMT) is the most promising candidate for cryogenic applications with significant conduction loss and switching loss reductions. Moreover, there is no carrier freeze out effect for the GaN HEMTs, which is applicable in extreme low temperature operating conditions. In this work, the efficiency of GaN HEMTs based power converters with different power levels (from several Watts to several kiloWatts) are evaluated at cryogenic temperature. Three different commercial GaN HEMTs are used in these power converters, including the Texas Instruments LMG5200 80 V GaN half-bridge power stage with integrated gate driver, the GaN Systems 650 V bottomcooled GaN HEMT GS66516B, and the 650 V top-cooled GaN HEMT GS66516T from GaN Systems. Moreover, two different cryogenic power converter evaluation methods (cryogenic chamber and liquid nitrogen channeled through cold plate) are investigated. Three of these power converters are evaluated by using a cryogenic chamber and such that the converter operating environment temperature can be regulated. One of the power converters is evaluated by using liquid nitrogen (LN2) channeled through a cold plate, where the gate driver can be designed to operate at non-cryogenic temperatures to ensure the safe operation of the system. Due to the degraded performance of conventional magnetic components, air core magnetics are used in these power converters to improve the converter efficiency. Efficiency improvements at cryogenic temperature are observed for all the GaN HEMTs and air core magnetics based power converters, which are promising for cryogenic power electronics applications.
Development of an apparatus and process for precision measurements of cryogenic thermal contraction of materials
Authors: Tuttle James , Jahromi Amir , Canavan Edgar , Nellis Jacob , Scheidler Justin 
Published: July 2024

Abstract
NASA frequently needs thermal contraction data for materials to be used in cryogenic space flight missions. To satisfy this need, we developed an apparatus and a high-precision technique for performing such measurements using a commercial fiber-optic-based position sensor. We describe the measurement process and its verification using a copper sample. We also present data for alumina and sintered samarium cobalt, which we characterized for potential NASA use.
Static friction testing of various materials in liquid nitrogen
Authors: Truchon J A , Miller F K , Nellis G F 
Published: July 2024

Abstract
The Deep Underground Neutrino Experiment will utilize charge readout planes (CRPs) that are submerged within liquid argon. These charge readout planes are part of a drift detector used measure the cascade of charged particles generated by the interaction of neutrinos with the argon nuclei. The CRPs require specially designed supports to ensure they remain precisely positioned even after the thermal contraction of the sensors and the cryostat that occurs during cooldown. These supports must also protect the cryostat floor and CRPs from potential damage due to thermal strain during cooldown. These objectives are satisfied by utilizing an intermediate slip plane within the support to provide a stress relief point with a lower friction coefficient than the interface between the sensor support and the cryostat floor. Therefore, the design of these supports requires knowledge of the static coefficient of friction for various materials at cryogenic temperatures. It was found that the coefficient of friction associated with materials such as metals, ceramics, and polymers have been studied very little at cryogenic temperatures. Specifically, there is not much data relative to the static coefficient of friction associated with polymers at low temperatures. Therefore, a test apparatus was developed to measure various materials’ cryogenic static coefficient of friction with the geometry required for the support design. Several tests with different materials were carried out using this test apparatus to identify a material combination with very different static coefficients of friction that can be used for the membrane to support interface and intermediate slip plane.
Magneto-structural phase transitions and two-dimensional spin waves in graphite
Authors: Gheorghiu N , Ebbing C R , Haugan T J 
Published: July 2024

AbstractWe have previously found experimental evidence for several quantum phenomena in oxygen-ion implanted of hydrogenated graphite: ferromagnetism, antiferromagnetism, paramagentism, triplet superconductivity, Andreev states, Little-Parks oscillations, Lamb shift, Casimir effect, colossal magnetoresistance, and topologically-protected flat-energy bands [1-6]. Triplet superconductivity results in the formation of Josephson junctions, thus with potential of being used for spintronics applications in the critical area of quantum computing. In this paper, we are showing new experimental evidence for the formation of two-dimensional (2D) spin waves in oxygen-ion enriched and in hydrogenated highly oriented pyrolytic graphite. The temperature evolution of the remanent magnetizationMrem(T) data confirms the formation of spin waves that follow the 2D Heisenberg model with a weak uniaxial anisotropy. In addition, the step-like features also found in the temperature dependence of the electrical resistivity between insulating and metallic states suggest several outstanding possibilities, such as a structural transition, triplet superconductivity, and chiral properties.
Oxidized structure and Compositional properties of 1144 phase FBS by analytical electron microscopy
Authors: Sung Z-H , Masi A , Lee JY , Duchenko A , Hu X , Kim A G , Celentano G 
Published: July 2024

Abstract
The 1144 phase (Ae1A1Fe4As4) shows a strong advantage of engineering fabrication among Fe (Iron)-based superconductor (FBS) family due to the robustness of its superconducting properties with respect to chemical inhomogeneities, granted by its uniform crystalline-layered structure. This regularity is furthermore associated to crystalline defects capable of acting as efficient pinning centers, from which high critical currents can achieved at high fields. Like other FBS phases, its lossless current-carrying capability can be remarkably degraded by distractions at grain boundaries (GBs). GB oxidation is an issue of upmost importance to the realization of the practical FBS application for high field (> 20T) magnet. In this study, we explore oxidized grain boundary and intrinsic grain structural properties of 1144 polycrystalline samples by applying analytical electron microscopy such as atomic resolution scanning transmission electron microscopy and atom probe tomography. These structural properties of samples produced by a mechanochemically assisted synthesis are evaluated following the degradation of superconducting properties due to oxidation. We observe a strong correlation between the contamination at grain boundaries and the decrease of transport properties of the bulk sample, while the crystallin structure seems to be not affected by the oxidation.