bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two new helium refrigerators for the LHC accelerator upgrade (HL-LHC) at CERN; From concept and tender to contract
Authors: Monneret E , Claudet S , Ferlin G , Gahier V , Wagner U 
Published: July 2024

Abstract
The High Luminosity LHC (HL-LHC) project is aiming to upgrade the Large Hadron Collider (LHC) at CERN by increasing its peak luminosity by a factor of five with respect to its nominal value. This upgrade will include the replacement of the final focusing superconducting magnets and additional superconducting radiofrequency crab cavities in the long straight sections of the interaction points 1 and 5 of LHC. The cryogenic heat loads in points 1 and 5 of the LHC accelerator will significantly increase, mainly because of the higher luminosity. Therefore, two new Refrigerators will be required in points 1 and 5, with each an equivalent capacity of 14 kW@4.5 K, including 3.25 kW@1.9 K. This paper presents the functional requirements and conceptual design, the key choices and specific challenges including the civil engineering constraints and the major technical requirements detailed in the Technical Specification documents for the supply from the European industry of two new helium Refrigerators for HL-LHC. A procurement contract based on this specification, was placed in 2022.
Commissioning of the ESS large-scale 20 K helium refrigeration system for the cryogenic moderator system
Authors: Tatsumoto H , Arnold P , Boros M , Horvath A , Segerup M , Tereszkowski P , Arriagada J , Huber R 
Published: July 2024

Abstract
At the ESS, a large-scale 20 K helium refrigeration system with a cooling capacity of 30.3 kW at 15 K, which is called Target Moderator CryoPlant (TMCP), has been designed to cool the cryogenic moderator system (CMS) where subcooled liquid hydrogen will be circulated at 1.0 kg/s through four hydrogen moderators where the total nuclear heating is estimated to be 17.2 kW for the proton beam power of 5 MW. The first phase of the TMCP installation and commissioning for the TMCP compressor skids and cold box was completed in 2019. The phase 2 installation of 300 m-long cryogenic helium transfer lines (CTLs) and a valve box located at one end of it in the Target building has been completed in the summer of 2022. Subsequently, the commissioning has been conducted until December 2022. This paper will describe the performance evaluation test results of the CTL heat load and pressure drop, the TMCP cooling capacity, and a test result of a failure action caused by instrument air failure.
Thermal analysis of 4 K J-T cryocooler equipped with an ejector
Authors: Hu Yayi , Wang Yanan , Wang Xiaotao , Dai Wei , Yang Zhaohui , Sun Yiwei , Li Haibing , Luo Ercang 
Published: July 2024

Abstract
This paper introduces a 4 K Helium Joule-Thomson (J-T) refrigeration system equipped with ejector technology to enhance thermodynamic efficiency, reduce the lowest cold head temperature, and avoid higher compressor suction pressure. The J-T cryocooler, pre-cooled by a Stirling cryocooler, typically requires a high compression ratio when operating at 4 K or below. The ejector serves as a device that converts pressure energy into kinetic energy, enabling it to draw in secondary fluid and then reconvert kinetic energy into pressure energy, thus increasing the pressure of the low-pressure fluid. To investigate the impact of the ejector on J-T refrigerator performance, this study employs a one-dimensional theoretical calculation. The results are used to establish a performance chart of the J-T refrigeration system with an ejector, which is compared to the system without an ejector. The analysis reveals a promising 10-20% improvement in performance with the ejector technology implemented.
Numerical modelling of thermoacoustic Stirling engines & refrigerators
Authors: Butson H , Gschwendtner M , Caughley A , Badcock R , Weijers H , Lumsden G 
Published: July 2024

Abstract
This paper investigates how numerical modelling can be used to explore thermoacoustic machines and compares the accuracy of the performance predictions for different simulation software. The software used includes one designed for modelling Stirling machines called ‘Sage’ and for modelling thermoacoustic machines called ‘DeltaEC.’ To compare their results, a model of both a thermoacoustic Stirling engine and refrigerator were developed from existing models in published papers, which contained experimental data to validate the numerical models. Overall, it was found that although both can accurately model thermoacoustic machines, they present different optimal conditions, and Sage’s solving method makes it more complex to model the standing wave.
A Retrospective on how Cryostats have changed with Cryostat Use and the Cooling Methods used to keep Superconducting Magnets Cold
Authors: Green Michael A 
Published: July 2024

Abstract
Prior to the invention of the vacuum flask by James Dewar in 1895, cryogenic temperatures below 100 K could not be sustained very long. The Development of the modern cryostat was an extension of the basic Dewar vacuum flask. The design of the cryostat, its insulation, and the cold mass support system is a function of the cryostat’s intended use. The type of refrigeration available also influenced the development insulation systems, support systems, transfer lines and electrical leads that are part of the cryostat. In recent years the availability and the cost of helium has been a significant factor in cryostat design and the methods used to cool and cool-down cryostats. This paper explores the historical development of today’s cryostats and how that can be tied to the source of cryogenic cooling. This paper is focused on earth bound cryostats. Some of the same principles can be applied cryostats used in space.
Investigation and perspectives of using Graph Neural Networks to model complex systems: the simulation of the helium II bayonet heat exchanger in the LHC
Authors: Stoklasa R , Calabrese N , Serio L 
Published: July 2024

Abstract
Large cryogenic systems, like those installed at CERN, are complex systems relying on many diverse physical processes and phenomena that are difficult to simulate and monitor in detail. With only a limited number of properties measured and made available for monitoring and control purposes, several processes contributing to the dynamics of the systems are ignored. This lack of information can reduce the accuracy and the capability of a model to track, predict, and anticipate the behavior of the system. Accurate analytical or numerical computer modeling can be developed to simulate the non-linear dynamics of the processes but they are complex, computationally intensive, and cumbersome to test, validate, and implement with different configurations and limited measurements of the hidden properties. In this work, we present our investigation of using Graph Neural Networks (GNN) to build a model of the helium II bayonet heat exchanger operating in the LHC at CERN. We are proposing to use a hybrid machine learning approach, where the parameters of the GNN model are estimated by a combination of supervised learning algorithms trained on experimental data and bounding physics equations and parameters. The GNN model was initially trained on data from the experiments performed on the LHC prototype magnet strings and validated on data extracted during the operation of the LHC machine. We demonstrate the model’s accuracy, repeatability, and robustness in various configurations. The model is also well inspectable and explainable, providing the time evolution of all variables. We report on the results and expected applications, which include predictive control, diagnostic, and operator training.
Modeling of cryogenic heated-tube flow boiling experiments of nitrogen and methane with Generalized Fluid System Simulation Program
Authors: Baldwin Michael , LeClair Andre , Majumdar Alok , Hartwig Jason , Ganesan Vishwanath , Mudawar Issam 
Published: July 2024

Abstract
Accurate modeling of cryogenic boiling heat transfer is vital for the development of extended-duration space missions. Such missions may require the transfer of cryogenic propellants from in-space storage depots or the cooling of nuclear reactors. Purdue University in collaboration with NASA has assembled a database of cryogenic flow boiling data points from heated-tube experiments dating back to 1959, which has been used to develop new flow boiling correlations specifically for cryogens. Computational models of several of these experiments have been constructed in the Generalized Fluid System Simulation Program (GFSSP), a network flow code developed at NASA’s Marshall Space Flight Center. The new Purdue-developed correlations cover the full boiling curve: onset of nucleate boiling, nucleate boiling, critical heat flux, and post-critical heat flux boiling. These correlations have been coded into GFSSP user subroutines. The fluids modeled are nitrogen and methane. Predictions of wall temperature are presented and compared to the test data.
Advanced ice lithography system using a micro-machined Joule-Thomson cooler
Authors: Qi Limin , Zheng Rui , Liu Dongli , Pei Haiyue , Zhao Ding , Qiu Min 
Published: July 2024

Abstract
This study introduces a novel ice lithography system integrated with a low-vibration micro-machined Joule-Thomson cooler. Ice lithography is an eco-friendly method for high-resolution nanofabrication on delicate substrates and requires to operate below 130 K in the vacuum of a microscope chamber. Previously, liquid nitrogen rather than cryocoolers was used to cool the system due to its low vibration, but it is both bulky and costly. To overcome these challenges, this study employs a low-vibration micro-machined cooler in a scanning electron microscope (SEM) for ice lithography. The design and methodology of the system are described in detail. The results show that the substrate can reach a temperature of 105 K within 30 minutes with a measured mechanical vibration of less than 10 nm, enabling high-resolution nanofabrication. As proof of concept, the system successfully fabricates nanoscale patterns on a silicon wafer. This low-vibration cooling system has great potential for use in cryogenic electron microscopes (cryo-EMs) in the future.
High Accuracy Resisitivity and Temperature Coefficient Measurements of Invar Wire from 5K to 300K
Authors: Hamilton B , Adams J L , Brisson J G 
Published: July 2024

Abstract
The temperature coefficient of resistivity is a critical element of many AC-based hot-wire measurements of thermal properties. At cryogenic temperatures, most metallic materials suitable for wire and film-based forms have either a temperature coefficient or absolute resistivity that is too small to enable practical, accurate measurements. Invar (36Ni 64Fe) controlled thermal expansion alloy has a significant temperature coefficient of resistance while also maintaining significant absolute resistivity at cryogenic temperatures, and so has seen some use in low temperature 3-omega measurements. Prior data on the temperature coefficient of resistivity of Invar is limited and the uncertainty is high. In this work, we present high-accuracy resistance and temperature coefficient data for this material from 5-300 K.
Study on irradiation effect of insulating materials for fusion superconducting magnets: temperature dependence of mechanical strength
Authors: Akiyama Y , Ohta A , Manabe Y , Sato F , Iwamoto A , Imagawa S , Utoh H , Nishijima S 
Published: July 2024

Abstract
Insulating materials used in the superconducting magnets of fusion reactors are exposed to cryogenic temperatures, intense radiations, and strong electromagnetic forces. In the experimental fusion reactor ITER, resin mixed with epoxy resin (EP) and cyanate ester (CE) (CE content: 40 wt.%) is used as a matrix of glass reinforced plastics (GFRP) as an insulating material to maintains mechanical strength and insulating performance in such environments. This composition ratio is basically determined by strength tests at room temperature or liquid nitrogen temperature, so the study at liquid helium temperature is required. In this study, the effects of the resin composition of GFRP on interlaminar shear stress (ILSS) at room temperature, liquid nitrogen temperature, and liquid helium temperature before and after γ-ray irradiation were evaluated. The ILSS after γ-ray irradiation of EP showed a maximum value at liquid helium temperature, while the addition of CE caused the ILSS after irradiation to show a maximum value at liquid nitrogen temperature. It was also shown that the temperature dependence of the ILSS decreased with increasing CE content. The results showed that the addition of CE to EP contributes to the improvement of radiation resistance, but excessive addition of CE promotes embrittlement at LHeT.
Mechanical properties and damage development in glass-fiber epoxy laminates subjected to tensile loading at sub-zero temperatures
Authors: Krzak A. , Al-Maqdasi Z. , Matula G. , Nowak A. J. , Joffe R. 
Published: July 2024

Abstract
In various structural applications polymer composites are exposed to sub-zero and even cryogenic temperatures which may initiate of microstructural damage. To anticipate these events, one needs to understand the behavior of composites in a sub-zero environment. This study focuses on damage initiation and accumulation, and its influence on the properties of cross-ply glass fibers epoxy composites at sub-zero temperatures. The effect of bromine modification of epoxy, and the dissolution in an organic solvent on the mechanical performance of the produced composite is also investigated. To evaluate the influence of a sub-zero environment on the mechanical performance of glass fiber epoxy laminates, tensile tests in a sub-zero environment of unconditioned specimens were carried out. The quasi-static tensile tests were performed to measure the elastic modulus of the composites while loading-unloading experiments were performed to monitor the initiation (and accumulation) of microstructural damage and its influence on the stiffness of glass fiber epoxy laminates. The results of cryogenic damage and fracture in the laminates are discussed with a focus on the degradation of properties of glass fiber crucial for their use in structural applications: strength and stiffness.
Property Variations in Modern REBCO Coated Conductors from Multiple Manufacturers
Authors: Bradford G , Jaroszynski J , Murphy G , Polyanskii A , Lee J , Larbalestier D C 
Published: July 2024

Abstract
The complex, multilayer structure of REBCO Coated Conductor (CC) poses significant challenges in the fabrication of high magnetic field devices where large stresses may initiate various forms of damage. Our goal is to peer below the cartoon representations of CC so that, amongst other things, we might better understand whether a CC from one manufacturer is interchangeable with that from another. This involves knowledge of a broad range of electromagnetic, geometric, microstructural, and Jc
(θ,B,T) properties, and their variations that collectively pose challenges for the fault tolerance of REBCO CC devices. Accordingly, comparative measurements of Jc
, visualization of flux penetration with Magneto-Optical Imaging (MOI), tape geometry from Scanning Electron Microscopy (SEM) of polished cross-sections, and extensive optical microscopy was performed on recently purchased samples from multiple manufacturers. Our analyses reveal many deviations from or characteristics absent from manufacturers’ specifications, while a comparison of different manufacturers’ mechanically and laser slit tapes shows a diverse array of slitting characteristics amongst the manufacturers and variation in properties those made to the same specification. Laser slit tapes from several manufacturers reveal ablated edges with damaged regions extending up to 50 μm, comparable to the damaged region found in the mechanically slit CC of this study. Overall, the aim of this study is to flesh out appropriate ways to understand the real conductor below the manufacturers’ cartoons to avoid surprises in our REBCO CC coil development program. The goal of this work was to perform a broad array of characterizations of the type needed for validation of purpose for making high field magnets: to our surprise we found a wide range of properties which greatly impact the mechanical strength and electromagnetic performance of solenoids composed of these conductors and reinforced the need for a broad characterization program for each conductor prior to its implementation.
Characterizing MEMS Switch Reliability for Cryogenic Applications such as Quantum Computing
Authors: Bradley Peter , Sorenson Elizabeth , Lauria Damian , Liew Li-Anne 
Published: July 2024

Abstract
Micro Electromechanical Systems (MEMS) switches offer many advantages over conventional larger switches. One potential application we are exploring is the use of commercial radio frequency (RF) MEMS switches for quantum computing applications. However, it is well-documented that cryogenic temperatures can cause mechanical reliability issues for MEMS. Furthermore, commercial RF MEMS switches are designed for room temperature operation, thus their reliability at cryogenic temperatures is unknown. Commercial MEMS switches are also packaged inside sealed housings, which prevent the use of optical methods for characterization and inspection. We are therefore developing test methods to evaluate the reliability of commercial RF MEMS switches at cryogenic temperatures. We describe our test methods and preliminary reliability test data from room temperature down to 55 K.
High attenuation electromagnetic interface filter for effective processing of audio signals
Authors: Prasanna Dasari Lakshmi , Tripathi Suman Lata , Mahmud Mufti , Wijayanto Inung 
Published: July 2024

Abstract
Suppressing the noise or unwanted signal from the raw signal makes the system work efficiently. Electromagnetic interface (EMI) can cause the system/device to lose the data, damage the electronic equipment, interrupt the audio, or video signals, lead to poor reception, etc EMI filters are used in telecommunications, military equipment, satellite communication, etc At the industry level, EMI filters are used for home appliances, medical equipment, motor controls, test equipment, etc In this paper, active and passive EMI filters are designed to avoid or attenuate EMI or noise (unwanted EMI signal) and implemented on Xilinx Nexys 4 Artix 7 FPGA board. The filters provide a significant improvement in the attenuation of the EMI. MATLAB tool is used to design the filters, which are highly immune to undesired signals, give better stability, and perform over a wide range of frequencies. Depending on the filters’ coefficients, the frequency response will be changed. Phase response and amplitude response of the EMI filters are calculated. Insertion loss of the active filter is 1.5836, and for the passive filter, 1.9382. The gain of active and passive filters is 0.7359 and 0.912 respectively. The return loss of the active and passive EMI filters is 20 dB. HDL code is generated using MATLAB for the implementation of filter on FPGA. Using MATLAB HDL coder for implementing is new and it simplifies the design, as a result development time is reduced. Xilinx Vivado tool is used for the implementation of active filter. The total on-chip power is 0.146 W. Dynamic power is 0.049 W, and device static power is 0.097 W. The utilization of LUTs and slice registers are less, compared to the previous filter implementation, which leads to reduce the cost of hardware implementation.
The interrelationship between multiple long-term conditions (MLTC) and delirium: a scoping review
Authors: Richardson Sarah Joanna , Cropp Alexandria Danielle , Ellis Samantha Wilhelmina , Gibbon Jake , Sayer Avan Aihie , Witham Miles David 
Published: July 2024

AbstractIntroductionDelirium and multiple long-term conditions (MLTC) share numerous risk factors and have been shown individually to be associated with adverse outcomes following hospitalisation. However, the extent to which these common ageing syndromes have been studied together is unknown. This scoping review aims to summarise our knowledge to date on the interrelationship between MLTC and delirium.MethodsSearches including terms for delirium and MLTC in adult human participants were performed in PubMed, EMBASE, Medline, Psycinfo and CINAHL. Descriptive analysis was used to summarise findings, structured according to Synthesis Without Meta-analysis reporting guidelines.ResultsAfter removing duplicates, 5256 abstracts were screened for eligibility, with 313 full-texts sought along with 17 additional full-texts from references in review articles. In total, 140 met inclusion criteria and were included in the final review. Much of the literature explored MLTC as a risk factor for delirium (n = 125). Fewer studies explored the impact of MLTC on delirium presentation (n = 5), duration (n = 3) or outcomes (n = 6) and no studies explored how MLTC impacts the treatment of delirium or whether having delirium increases risk of developing MLTC. The most frequently used measures of MLTC and delirium were the Charlson Comorbidity Index (n = 98/140) and Confusion Assessment Method (n = 81/140), respectively.ConclusionExisting literature largely evaluates MLTC as a risk factor for delirium. Major knowledge gaps identified include the impact of MLTC on delirium treatment and the effect of delirium on MLTC trajectories. Current research in this field is limited by significant heterogeneity in defining both MLTC and delirium.
Use of Maternal Race and Weight Provides Equitable Performance in Serum Screening for Open Neural Tube Defects
Authors: Messerlian Geralyn , Strickland Sydney Webb , Willbur Jordan , Vaughan Christine , Koenig Shelby , Wright Taylor , Palomaki Glenn E 
Published: July 2024

Abstract

Background
Maternal serum alpha-fetoprotein (AFP) levels are used in screening for open neural tube defects (ONTD). Historical reports show that AFP levels and maternal weights are higher in self-reported Black than White individuals, but recent reports question the need to account for these variables in screening. Our study compares screening performance with and without accounting for race.

Methods
Retrospective analysis was performed on deidentified prenatal screening records including maternal weight and self-reported race of White or Black. Gestational age-specific medians and weight-adjusted multiples of the median levels were calculated separately for each group and using a race-agnostic analysis. Outcome measures included the proportion of screen-positive results.

Results
Records for analysis (n = 13 316) had an ultrasound confirmed gestational age between 15 and 21 completed weeks, singleton pregnancy, and self-reported race. Race was Black for 26.3%. AFP levels for pregnancies in Black individuals were higher than in White individuals: 6% to 11% depending on gestational age. Race-specific gestational age and maternal weight analyses resulted in similar screen-positive rates for self-reported White and Black individuals at 0.74% vs 1.00%, respectively (P = 0.14). However, use of race-agnostic analyses resulted in a screen-positive rate that was 2.4 times higher in Black than White individuals (P &lt; 0.001).

Conclusion
These data show that the historical method of accounting for maternal race and weight in prenatal screening for ONTD provides equitable performance. Using a race-agnostic methodology results in an increased screen-positive rate and a disproportionate rate of required follow-up care for individuals who self-identify as Black.