bluuebunny/crossref_metadata_2025_split huggingface dataset:
Atypical magnetic resonance imaging findings of a vertebral melanotic melanoma in a dog
Authors: Prodger Alice , Rodriguez Tomas Elvira , Mallol Claudia , Costa Taiana , Benito Miguel 
Published: January 2024

AbstractAn 8‐year‐8‐month‐old whippet was investigated by magnetic resonance imaging for acute thoracolumbar discomfort and pelvic limb stiffness, which had progressed to severe ambulatory paraparesis and proprioceptive ataxia of the pelvic limbs in the 24 hours before presentation. An aggressive, extradural T10 vertebral mass‐like lesion was identified, with resultant marked compression of the spinal cord. The lesion was heterogeneously T2‐weighted hyperintense and moderately T1‐weighted hyperintense relative to the adjacent vertebrae and paravertebral musculature. Cytological analysis of the lesion was consistent with a melanotic melanoma, which was confirmed by histopathological analysis and immunohistochemistry. The vertebral column is an uncommon location for either primary or metastatic melanomas in both humans and veterinary species. This lesion was particularly unusual in that its imaging characteristics were not typical for melanotic melanoma. This case report illustrates the unusual anatomical and imaging features of this tumour and outlines the diagnostic considerations pertinent to this case.
Association between troponin I levels and mortality among patients undergoing acute high‐risk abdominal surgery—A cohort study
Authors: Kanstrup Charlotte Tiffanie Bendtz , Serup Camilla Mattesen , Svarre Kristina Johansen , Rasmussen Maja Christine , Lundstrøm Lars Hyldborg , Kleif Jakob , Bertelsen Claus Anders 
Published: January 2024

AbstractBackgroundMyocardial injury after noncardiac surgery (MINS) is associated with 30‐day mortality in heterogeneous surgical populations but is barely described after acute high‐risk abdominal surgery. The impact of dynamic changes has not previously been investigated. The objectives were to determine the incidence of MINS in this population, the association between mortality and MINS, and whether plasma troponin I (TnI) dynamics have any impact on mortality.MethodsA prospective cohort study of 341 patients undergoing acute high‐risk gastrointestinal surgery was conducted. Plasma TnI was measured at the first four postoperative days. MINS was defined as any increased TnI level >59 ng/L. TnI dynamic required either two succeeding measurements of TnI >59 ng/L with a >20% increase/fall or one measurement of TnI >59 ng/L with a succeeding measurement of TnI <59 ng/L with a >50% decrease. Adjusted mortality rates were calculated using inverse probability of treatment weighting and competing risk analyses.ResultsThe incidence of MINS was 23.8% and dynamic TnI changes occurred in 15.6% of the patients. The unadjusted 30‐day and 1‐year mortality were 19.8% and 35.9% in patients with MINS, compared with 2.7% and 11.6%, respectively, in patients without MINS (p < 0.001). After adjusting, the differences remained significant. There was no difference in mortality between patients with or without dynamic changes in TnI level.ConclusionMINS occurred frequently and was associated with increased mortality. TnI monitoring might help identify patients with increased risk of mortality and improve care. Research on preventive measures and treatments is warranted.Trial Registration Number and AgencyClinicalTrials.gov Identifier: NCT05933837, retrospective registered.
Behavior of polar bear (Ursus maritimus) cubs post‐den emergence at the Detroit Zoo
Authors: Gartland Kylen N. , Humbyrd Mary , Brightrall Tami , Meister Betsie , Fuller Grace 
Published: January 2024

AbstractIn the wild, female polar bears (Ursus maritimus) with cubs may spend extended periods of time within the den following initial emergence. As a result, studying behavioral development of cubs at the denning site has been difficult and unreliable. Although care staff at zoological institutions have easier access to animals, every effort is made to minimize intrusions to maternal groups, which presents research limitations. Detroit Zoological Society staff used audio‐equipped cameras installed in behind‐the‐scenes spaces to conduct approximately 9 weeks of monitoring on two female polar bear cubs of the same litter, one of whom (Laerke) was hand‐reared while the other (Astra) was mother‐reared. Monitoring spanned ages 14–24 weeks and consisted of 12, 5‐min focal observations per observation day timed to evenly cover the entire 24‐h day. Using generalized linear mixed models, we examined relationships between behavior and time of day, hour, and age. We also conducted descriptive analyses and used these to draw comparisons between the two cubs where appropriate. Despite different rearing environments, both cubs had highly comparable patterns of inactive, locomotory, and independent play behaviors. Astra generally decreased time spent nursing and in proximity to Suka as she aged. Data presented here represent a continuation of previous neonatal observations conducted on Astra, adding to the minimal body of knowledge currently available on first year polar bear cub development. We also report successful mitigation of stereotypic behavior in Laerke. Further studies of captive maternal groups can provide insight into this critical developmental stage, supporting both captive‐based breeding efforts and in situ conservation efforts.
Optimization of Energy Management Control Strategy for Hydrogen-Electric Hybrid Train
Authors: Sun Shijie , Gao Yang , Wang Jian , Shi Lei , Chen Limei , Xiang Weiran , Li Wenrong 
Published: January 2024

AbstractIn order to enhance the stability of the energy regulation of the hydrogen-electric hybrid train and reduce the impact on the train bus of the hybrid system during the energy regulation process, an improved rule-based instantaneous power control strategy is proposed, in which the bus voltage is introduced into the control link to enhance the system stability. The simulation results prove that the optimized control strategy improves the stability of the high-voltage DC link of the hybrid system, avoids the high-voltage surging to the super-capacitor system and the traction system, and extends the service life of the super-capacitor at the same time.
Safety Technologies and Challenges of Hydrogen-Powered Rail Transport
Authors: Wang Jian , Gao Yang , Sun Shijie , Shi Lei 
Published: January 2024

AbstractAs one of the many energy alternatives, the interest in hydrogen-powered rail transport is gradually increasing worldwide, and some railway vehicles powered by hydrogen are currently in operation or undergoing experimental projects. However, due to the unsafe and unstable nature of hydrogen energy, hydrogen has potential leakage and explosion hazards in all rail transport applications. This paper summarizes the main application technologies of hydrogen safety in light of the research progress and unsafe factors in the process in the field of hydrogen-powered rail transport in various countries, at the same time clarifies the development challenges and difficulties of hydrogen-powered rail transport in the future, and makes suggestions for the development of hydrogen-powered rail transport safety in China.
Design Method of the Hydrogen Liquefaction Process with Catalyst-Filled Heat Exchanger Model
Authors: Lv Cui , Zhou Gang , Wang Jinzhen , He Ming , Wu Jihao , Gong Linghui 
Published: January 2024

AbstractHydrogen liquefaction is a crucial process in the liquid hydrogen industry, and the use of liquid hydrogen is becoming increasingly important for storing and transporting hydrogen over long distances. Hydrogen has two spin isomers, that is ortho and para hydrogen. One of the challenges in this process is the conversion of ortho to para hydrogen in the heat exchanger. As the conversion process releases heat and is a spontaneous behavior, it is important to ensure that the content of para hydrogen in the final product is at least 95%. Unfortunately, there are currently no known commercial models that contain catalyst-filled heat exchangers for converting ortho hydrogen to para hydrogen. In this paper, Aspen Hysys is used to construct a new design method for hydrogen liquefier with O-P hydrogen conversion heat exchanger. Using this model, one 5 ton per day hydrogen liquefier is designed, and the key parameters of the process are obtained, which will provide a new method for the design of hydrogen liquefaction process in the future.
Hydrogen Leakage Detection in Confined Spaces with Drift Suppression Based on Subspace Alignment
Authors: Se Haifeng , Jiang Jinhai , Sun Chuanyu , Song Kai 
Published: January 2024

AbstractGas sensor has been widely used in flammable gas detection. In order to solve the problem that gas sensors are susceptible to drift in hydrogen leakage detection in confined spaces, a drift compensation framework based on subspace alignment is proposed. First, global domains and subdomains are aligned simultaneously in the new subspace, thus reducing the distribution difference between the source domain and the target domain. Then, the proposed method utilizes extreme learning machine (ELM) to iteratively refine the prediction results of the target domain, and continuously optimizes the subspace and classifier. In this way, the proposed method realizes drift compensation at the feature level. Compared with the existing methods, the proposed method achieves the highest accuracy of 79.83% in the long-term drift scenario. Therefore, the experimental results show that the proposed method is competent for hydrogen leakage detection with drift, and can provide a reference for the design of drift compensation method based on gas sensors.
Design of 10 L/s Liquid Hydrogen Pump with Integrated Inducer and Centrifugal Impeller
Authors: Li ZiWei , Lv Cui , Wu Jihao , Gong Linghui , Wang Jinzhen , Shang Jin , He Ming 
Published: January 2024

AbstractWith the global focus on energy and environmental issues, hydrogen energy development has become more and more important. The liquid hydrogen pump is an important equipment for hydrogen transportation, whose performance is significantly decided by the impeller. In this paper, we designed an integrated impeller with an inducer and an centrifugal impeller and optimized the axial length and outlet angle of the centrifugal impeller. Grid independence and cross validation prove that the simulation model and results are reliable. It is worth noting that a high roughness is given to the impeller surfaces in our simulation to obtain results closer to the real situation. By analyzing the pressure and relative liquid flow angle distribution in the fluid domain, the structural design of the impeller is optimized, and then the performance curve is obtained. The simulation results will provide a guidance for the manufacture of our liquid hydrogen pump, and also provide a reference for the design and manufacture of other liquid hydrogen pumps.
Experimental Research on High-Pressure Hydrogen Leakage and Diffusion of Hydrogen Refueling Station
Authors: Jiang Bin , Zhen Tongshen , Fang Fangfang 
Published: January 2024

AbstractAs the infrastructure to provide hydrogen for hydrogen fuel cell vehicles, hydrogen refueling station is a very important part of hydrogen energy utilization. However, due to the characteristics of hydrogen, such as flammability and explosion, low density, wide range of explosive limit concentration, hydrogen refueling station accidents often occur. The existing research on hydrogen refueling stations often uses the method of numerical simulation, and mainly considers the leakage of hydrogen storage tank. There are few relevant experimental studies and little consideration is given to the case of hydrogen pipeline leakage. In order to explore the phenomenon and rule of high-pressure hydrogen leakage and diffusion in the pipeline of hydrogen refueling stations, a full-size high-pressure hydrogen leakage test facility is built based on a real hydrogen refueling station. The vehicle-mounted high-pressure hydrogen storage tank is used as the high-pressure hydrogen gas source to provide constant hydrogen pressure to the test section through the combination of different valves in the pipeline and the instrument control system. By changing different leakage sizes and pressures, the concentration distribution and influence factors after hydrogen leakage are analyzed, which provides an important basis for the optimal layout and operation and maintenance of the safety facilities of the existing hydrogen refueling station.
Deep Neural Network for Prediction of Adsorbent Selectivity on Hydrogen Purification
Authors: Li Chenglong , Xie Chengsi , Zong Yi , Chahine Richard , Yang Tianqi , Ye Feng , Xiao Jinsheng 
Published: January 2024

AbstractWith emergence of new materials, more and more materials are available for adsorption and separation processes. The adsorption selectivity of adsorbent to adsorbate is one of the important indicators in choosing materials. Because the adsorption experiment of the mixture is time-consuming and difficult, the selectivity of the adsorbent is generally calculated by the ideal adsorbed solution theory (IAST). Taking the CO2/H2 gas mixture as an example, this paper proposes a new adsorption selectivity calculation method based on a deep neural network (DNN) with 5 hidden layers, which takes the molar fraction of CO2, adsorption pressure and Langmuir adsorption isotherm parameters as the inputs of DNN. Combining the DNN and the NIST/ARPA-E database to quickly and accurately calculate the adsorption selectivity, the hydrogen purification and carbon dioxide storage materials can be quickly screened.
Scheduling of Renewable Energy Hydrogen Production System Based on Two—Stage Distribution Robust Optimization
Authors: Xia Luohui , Wu Bin , Zhou Linwei , Liang Tao , Liu Zicong 
Published: January 2024

AbstractHydrogen energy has various advantages such as cleanliness, storage and high energy carrier, which is considered to be one of the key paths to achieve the goal of “double carbon”. Utilization of hydrogen production in renewable energy is an important technical means to achieve new energy amazing and energy cleaning utilization. In response to the uncertainty characteristics of local scenery resources and local electricity load and hydrogen load demand, considering the investment cost of hydrogen storage system and the influence of flexible load of electric load on the optimal operation of the system, a two-stage distributed robust optimization model for hydrogen production system (H2-RES) from renewable energy is established, the capacity of the first stage hydrogen production system is determined by the system economy, and the second stage is designed to optimize the real-time scheduling of the system, aiming at the total operating cost, which is solved by C&CG algorithm, finally, an example is given to verify the validity of the proposed model.
Multivariate Based Alkaline Electrolyzer Digital Twin Model Construction
Authors: Liang Tao , Liu Zicong , Sun Hexu , Tan Jianxin 
Published: January 2024

AbstractElectrolytic water hydrogen production systems are highly coupled and operate under complex and dangerous conditions, making it difficult to carry out extreme experiments on physical objects. In this paper, the alkaline electrolyzer is studied and mathematical and three-dimensional models are developed for it. The System operation data shows that temperature, pressure and alkaline flow rate all have effects on the hydrogen concentration in oxygen and voltage. Among them, hydrogen concentration in oxygen is one of the important factors affecting the safety of the system, and changing both pressure and alkali flow rate respectively will cause significant changes in hydrogen concentration. Based on the system operation data, a multivariate nonlinear fitting of the empirical equation using Matlab was performed to establish the voltage model, Faraday efficiency model, hydrogen concentration in oxygen model and system pressure model of the alkaline electrolyzer. And the model simulation results were analyzed and verified theoretically, which were consistent with the actual engineering. The mathematical model of the alkaline electrolyzer is combined with the 3D model, and the digital twin model of the alkaline electrolyzer is controlled in real time by PLC. The mapping of the alkaline electrolyzer in the virtual space is realized, which provides an experimental platform for the subsequent study of wide power fluctuation.
Thermal Analysis and Optimization of Cold-Start Process of Alkaline Water Electrolysis System
Authors: Deng Xintao , Yang Fuyuan , Li Yangyang , Dang Jian , Ouyang Minggao 
Published: January 2024

AbstractIn this paper, a thermal model of commercial alkaline water electrolysis system is presented, including energy and mass balance model between system components and a two-stage graybox model of alkaline electrolyzer. The aim of this work is to study and improve the thermal behavior during cold-start process of electrolysis system. The model is used to simulate the cold-start process under various parametric settings such as electrolyte flow rate and electrolyte volume. Then, several optimization schemes are proposed and evaluated to be promising.
Effect of Flow Channel Blockage on the Scale-Up of Proton Exchange Membrane Fuel Cells
Authors: Wang Bin , Pan Weitong , Tang Longfei , Zhang Guoyu , Gao Yunfei , Chen Xueli , Wang Fuchen 
Published: January 2024

AbstractOptimizing flow field structure can effectively improve the performance of Proton Exchange Membrane Fuel Cell (PEMFC). Adding the block in the flow channel is one of the approaches. In this work, the enhanced transport characteristic of the block is re-examined, and its effect on the performance of the fuel cell scale-up is further revealed. The models of single-channel fuel cells with different lengths L and blockage ratio β are developed. Results show that the best cell performance exhibits when β = 100% due to the combined effect of the block and upstream zone. The convection appears below the block, and higher upstream pressure is induced, both of which increase the oxygen concentration at the catalyst layer. Besides, results indicate that the performance of the scaled-up fuel cell with blockage increases at a slower rate. Combined with the pump power, it is found that the addition of the block with β = 100% is indeed beneficial for the fuel cell scale-up. The findings of different blockage effects on different-sized cells provide guidelines for the flow field design.
Strategic Analysis of Hydrogen Energy Policies and Technology Layout in Major Countries
Authors: Han Xiao , Yan Hua-guang , Kang Jian-dong , Li Yang 
Published: January 2024

AbstractIn the context of the global clean and low-carbon energy transition, hydrogen energy has become an important direction for energy technology innovation in the contemporary world. Many countries around the world have paid great attention to the development of hydrogen energy and leveraged it to the national strategies. This study firstly reviews the development of global hydrogen energy, focusing on the global hydrogen energy supply, hydrogen energy demand, the current situation and development trend of hydrogen energy. Secondly, based on data collected from government websites, key R&D institutions and well-known databases (e.g. CODIS database), a strategic analysis of hydrogen energy policies and technologies of main countries is conducted. In terms of policy, textual analysis is used to analyse the global hydrogen energy layout direction and the strategic positioning, strategic layout and strategic objectives of hydrogen energy in countries such as the United States, European Union, Japan and China. In terms of technology, the keyword search method is used to obtain data on scientific research projects in the field of hydrogen energy, and quantitative analysis is conducted to analyse the characteristics of the technical layout of global hydrogen energy research projects, and to analyse the funding of hydrogen energy projects and the focus of hydrogen energy technology research. Finally, suggestions for the future development of hydrogen energy are discussed.
Internal structure of hairy rotating black holes in three dimensions
Authors: Gao Ling-Long , Liu Yan , Lyu Hong-Da 
Published: January 2024

Abstract
We construct hairy rotating black hole solutions in three dimensional Einstein gravity coupled to a complex scalar field. When we turn on a real and uniform source on the dual CFT, the black hole is stationary with two Killing vectors and we show that there is no inner horizon for the black hole and the system evolves smoothly into a Kasner universe. When we turn on a complex and periodic driving source on the dual CFT with a phase velocity equal to the angular velocity of the black hole, we have a time-dependent black hole with only one Killing vector. We show that inside the black hole, after a rapid collapse of the Einstein-Rosen bridge, oscillations of the scalar field follow. Then the system evolves into the Kasner epoch with possible Kasner inversion, which occurs in most of the parameter regimes. In both cases, one of the metric fields obeys a simple relation between its value at the horizon and in the Kasner epoch.
The effect of surface finish and post-processing on mechanical properties of 17-4 PH stainless steel produced by the atomic diffusion additive manufacturing process (ADAM)
Authors: Opoz Tahsin Tecelli , Burgess Andrew , Ahuir-Torres Juan Ignacio , Kotadia Hiren Ramniklal , Tammas-Williams Samuel 
Published: January 2024

AbstractThis study investigates the influence of surface finish and post-processing conditions on the mechanical properties of 17-4 PH stainless steel (SS) produced using the atomic diffusion additive manufacturing process (ADAM). Diverse sample orientations, including horizontal (0°), 30°, 60°, and vertical (90°), were examined, with selected samples undergoing post-processing through machining, polishing, and heat treatment. Tensile strength testing, surface roughness measurement, and hardness measurement were conducted to assess the effect of surface finish conditions and post-processing on mechanical properties. The results reveal significant variations in the tensile strength of the samples based on the build orientation (183.5 to 1034.5 MPa), and subsequent machining. Notably, post-built machining is found to enhance both the absolute ultimate tensile strength (UTS) and the isotropy of the material. Further improvements are attainable through heat treatment. A microstructure analysis, in conjunction with tensile testing outcomes, demonstrates the potential for refining the properties of ADAM-printed samples through suitable machining, heat treatment, and geometry modifications. This study identifies avenues for ongoing process development and outlines possibilities for enhancing mechanical properties of additive manufactured parts, particularly through ADAM process.
The triangulation complexity of elliptic and sol 3-manifolds
Authors: Lackenby Marc , Purcell Jessica S. 
Published: January 2024

AbstractThe triangulation complexity of a compact 3-manifold M is the minimal number of tetrahedra in any triangulation of M. We compute the triangulation complexity of all elliptic 3-manifolds and all sol 3-manifolds, to within a universally bounded multiplicative error.