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numerical modeling of Concentration Behaviors of Carbon, Oxygen, and Aluminum During Ruhrstahl-Heraeus Process

METALS AND MATERIALS INTERNATIONAL 2025年 1-24页

作者： Youn, Tae Ung Bae, Saeum Yi, Kyung Woo Seoul Natl Univ Dept Mat Sci & Engn Seoul 08826 South Korea Seoul Natl Univ Res Inst Adv Mat RIAM Seoul 08826 South Korea

Ultralow-carbon steel production is crucial for several applications in the steelmaking industry. Ruhrstahl-Heraeus (RH) degassing is a prominent method for decarburization, achieved by blowing inert (Ar) gas into melt, inducing circulation between ladle and vacuum vessel. Although empirical models provide some insights, the complexity of RH operations necessitates advanced numerical modeling for various parameters influencing melt flow circulation and chemical reactions. This study proposes a comprehensive numerical model to simulate fluid flow and concentration behaviors with various operating parameters during RH operations. The numerical model incorporates melt circulation, plume shape, bubble expansion, and buoyancy forces to predict changes in carbon, oxygen, and aluminum concentrations throughout the process. Key elements include decarburization and deoxidation reactions and operating parameter effects including oxygen blowing (OB) and carbon addition in RH. The calculation model follows a procedure that significantly reduces calculation time while performing calculations including various parameters. Verification with plant data shows good agreement, demonstrating capabilities of predicting calculations. Accordingly, a difference of 0.57%p is recorded for carbon concentration. For calculations including OB and carbon addition, differences of 0.79%p and 0.35%p are recorded, respectively. The findings of this study provide a valuable reference for future investigations and process optimization in RH steelmaking.

关键词： RH numerical modeling Flow Concentration Reaction rates

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numerical modeling and experimental validation of low velocity impact of woven GFRP/CFRP composites

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JOURNAL OF COMPOSITE MATERIALS 2025年第3期59卷 283-303页

作者： Sommer, Drew E. Berkowitz, Katherine Werner, Brian T. Long, Kevin N. Skulborstad, Alyssa J. Sandia Natl Labs Engn Sci Ctr 1515 Eubank SE Albuquerque NM 87185 USA Sandia Natl Labs Mech Mat Livermore CA USA

Low-velocity impact of 2D woven glass fiber reinforced polymer (GFRP) and carbon fiber reinforced polymer (CFRP) composite laminates was studied experimentally and numerically. Hybrid laminates containing blocked layers of GFRP/CFRP/GFRP with all plies oriented at 0 degrees were investigated. Relatively high impact energies were used to obtain full perforation of the laminate in a low-velocity impact setup. numerical simulations were carried out using the in-house transient dynamics finite element code, Sierra/SM, developed at Sandia National Laboratories. A three-dimensional continuum damage model was used to describe the response of a woven composite ply. Two methods for handling delamination were considered and compared: (1) cohesive zone modeling and (2) continuum damage mechanics. The reduced model size achieved by omission of the cohesive zone elements produced acceptable results at reduced computational cost. The comparison between different modeling techniques can be used to inform modeling decisions relevant to low velocity impact scenarios. The modeling was validated by comparing with the experimental results and showed good agreement in terms of predicted damage mechanisms and impactor velocity and force histories.

关键词： Fiber reinforced polymer damage mechanics numerical modeling composite laminate dynamic fracture low velocity impact

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numerical modeling and Optimization Design of Embedded Rubber Waterstops in Tunnel Lining

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POLYMERS 2025年第3期17卷 421-421页

作者： Fan, Xuan Wang, Hailin Xie, Chaoran Lei, Mingfeng Gong, Chenjie Cent South Univ Sch Civil Engn Changsha 410075 Peoples R China Hunan Prov Commun Planning Survey & Design Inst Co Changsha 410200 Peoples R China

Tunnel water leakage is a common issue. Embedded rubber waterstops are crucial in ensuring the waterproofing performance of mountain tunnels. The deformation performance of a rubber waterstop directly impacts its effectiveness, with structural parameters playing a key role. This study employs numerical simulation methods to quantitatively assess the impact of structural parameters-such as the central hole, ribs, and flanges-on the deformation performance of waterstops. The parametric analysis reveals significant variations in how different structural components affect the deformation performance, as indicated by the defined deformation stress influence rate. Specifically, the deformation performance of the embedded waterstop under tensile, compression, and settlement deformations shows a correlation with factors such as the ratio of the central hole opening rate to thickness and the inner and outer diameters. Additionally, an optimization analysis, taking both economic and performance factors into account, was conducted on 16 types of waterstops with different central hole parameters, from which the optimal waterstop was selected. This research provides a scientific basis for enhancing the deformation performance of waterstops and optimizing their structure.

关键词： tunnel lining embedded rubber waterstop numerical modeling deformation performance optimization design

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numerical modeling of unidirectional sulfate attack on tunnel lining concrete considering water evaporation at free face

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CEMENT AND CONCRETE RESEARCH 2025年 190卷

作者： Fan, Zirui Zou, Dujian Zhang, Ming Qin, Shanshan Liu, Tiejun Harbin Inst Technol Sch Civil & Environm Engn Shenzhen 518055 Peoples R China Harbin Inst Technol Guangdong Prov Key Lab Intelligent & Resilient Str Shenzhen 518055 Peoples R China Shenzhen Polytech Univ Sch Construct Engn Shenzhen 518055 Peoples R China

Severe scaling and spalling are commonly observed on tunnel lining surfaces in sulfate-rich environments. Due to humidity gradients, sulfate solution in rock fissures migrates through capillary action to the concrete exposed face, leading to physical crystallization precipitation at free-face zone and chemical sulfate attack at soil-facing zone, resulting in concrete expansion and crack. Existing models focus on full immersion or wet-dry cycles, which have obvious errors in predicting concrete damage under similar partial immersion. Considering the time- varying characteristics of saturation, porosity, calcium leaching and crack, a transport-reaction-expansion model for lining concrete under dual sulfate attacks and water evaporation was established. The spatiotemporal distribution of phase composition and the influence of modeling parameters on concrete expansion were revealed. The expansion strain caused by dual sulfate attacks and changes in the water evaporation zone was discussed. These findings provide a theoretical foundation for the durability design of lining concrete in sulfate- rich environment.

关键词： Sulfate attack Tunnel lining concrete Water evaporation Crystallization pressure numerical modeling

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numerical modeling of Bowel Sound Propagation: Impact of Abdominal Tissue Properties

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APPLIED SCIENCES-BASEL 2025年第6期15卷 2929-2929页

作者： Deng, Xingyu Xu, Yazhen Zou, Yuanwen Sichuan Univ Coll Biomed Engn Chengdu 610065 Peoples R China

Bowel sounds, produced by intestinal peristalsis, are essential for diagnosing gastrointestinal disorders. However, acquiring and analyzing bowel sounds is challenging due to their unpredictable nature and individual variability. Biological tissues can affect bowel sounds during propagation, resulting in varying degrees of signal attenuation between the sound source and the transducer. This study aims to develop a numerical model of bowel sound propagation in the abdominal cavity, focusing on the impact of different biological layers on signal attenuation. Validation of the model demonstrated strong consistency between simulated and actual bowel sound signals, confirming the model's accuracy and reliability. The model accounted for adipose tissue thickness, ranging from 5 to 20 mm across individuals, while muscle and skin thicknesses remained constant. Results indicated that signal attenuation increases with both the propagation distance and adipose tissue thickness. These findings provide insights into how tissue layers influence bowel sound propagation, offering a theoretical foundation for developing personalized and precise monitoring devices.

关键词： bowel sounds individual wave component signal attenuation numerical modeling tissue properties

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numerical modeling of Steady Smoldering Propagation in Slim Char Rods Characterized by Oxidation of Char Cone

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COMBUSTION SCIENCE AND TECHNOLOGY 2025年第2期197卷 423-439页

作者： Yan, Shengtai He, Fang Li, Shuqi Zhang, Yi Wang, Youtang Zha, Jianwen Shandong Univ Technol Sch Transportat & Vehicle Engn Zibo Shandong Peoples R China Shandong Univ Technol Sch Transportat & Vehicle Engn Xincun West Rd 266 Zibo 255049 Shandong Peoples R China

To clarify the mechanism on natural steady smoldering, propagation of smoldering in slim char rods was investigated theoretically and experimentally. A numerical model of smoldering propagation in char rods characterized by oxidation of char cone (the conical reaction zone) was developed based on energy conservation as well as oxygen transport through ash and flue gas. Shape and temperature field of char cone were calculated via Gauss-Seidel iteration, and sensitivity analysis of parameters was performed. Experiments on propagation velocity, shape and temperature field of char cone were also performed using char rods with different materials and diameters to validate the model. It is found that the predicted results agree well with the experimental results, indicating that the model is able to describe steady propagation of smoldering of char rods appropriately. The main parameters affecting the height and temperature of char cone are activated energy of fuels and ambient pressure, respectively, and the height of char cone is more sensitive than temperature to the parameters.

关键词： Char rods steady smoldering propagation char cone numerical modeling

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numerical modeling of the transport mechanism of NH3/H2 mixtures in nanoporous materials

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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 2025年 101卷 63-72页

作者： Shen, Ao Bhatia, Suresh K. Duan, Yufeng Xu, Yifan Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Univ Queensland Sch Chem Engn St Lucia Qld 4072 Australia Southeast Univ Minist Educ Sch Energy & Environm Key Lab Energy Thermal Convers & Control Nanjing 210096 Peoples R China Nanjing Inst Environm Sci Minist Ecol & Environm Peoples Republ China Nanjing 210042 Peoples R China

Understanding the nanotransport properties of NH3 and H2 is critical for designing adsorption and separation materials. In this work, we develop a novel numerical model at the molecular level by incorporating the M - S approach and effective medium theory, and provide a rigorous and analyzable simulation implementation for a binary transport system of NH3 and H2. In addition, the effect of pore length nonuniformity is simultaneously incorporated. The results show that high temperatures and large radii are detrimental to adsorption but favorable for diffusion at the single-pore scale, while the greater conductance increase in large pores dominates the fluid transport property in the pore network. The existence of a pore length distribution can induce greater effective diffusivity and lower apparent tortuosity within the pore network. Moreover, we confirm that at 300 K, the equilibrium selectivity of NH3 over H2 reaches approximately 28 in a uniform pore network with a pore radius of 0.25 nm, indicating the feasibility of nanoporous silica materials for use in adsorption separation of NH3 and H2 mixtures.

关键词： Maxwell-stefan approach Effective medium theory Oscillator model Binary mixture system numerical modeling NH 3 and H 2 separation

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numerical modeling of the origin and process of groundwater hypersalinization in a coastal dry environment in northwestern Mexico

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JOURNAL OF SOUTH AMERICAN EARTH SCIENCES 2025年 153卷

作者： Monzalvo, M. M. Escolero, Oscar Olea-Olea, Selene Morales-Casique, Eric Univ Nacl Autonoma Mexico Posgrad Ciencias Tierra Inst Geol Ciudad Univ Ciudad De Mexico 04510 Mexico Univ Nacl Autonoma Mexico Dept Dinam Terr Superficial Inst Geol Ciudad Univ Ciudad De Mexico 04510 Mexico

Concentrations double the salinity of seawater were found in a large portion of Ejido Chapala, southwest San Quint & iacute;n's aquifer, in northwestern Mexico. A zone with the impacts of seawater intrusion and high evapotranspiration rates was studied using different methodologies with the purpose of understanding the natural occurrence of hypersaline groundwater. A numerical groundwater flow and transport model was developed to test some hypotheses regarding the driving forces that gave it its hypersaline characteristic. To feed the numerical model, well-drilling analysis, electrical logs, step-drawdown tests, and geophysical assessments were performed. Two field piezometric campaigns were conducted in 2013 and 2015, accompanied by Electrical Conductivity (EC) profiles to gather the information to calibrate the model. numerical modeling indicated that seawater serves as the primary source of inflow, currently with groundwater flowing towards the northeastern border. Mass concentration simulations illustrated the encroachment of seawater over time, in addition to solute migration attributed to the presence of brine hosted in fine sediments, leading to elevated Total Dissolved Solids (TDS) concentrations. Additionally, water samples were collected to perform hydrochemical and isotopic analyses revealing that midwestern well waters predominantly fall into the calcium magnesium sulfate and sodium chloride type categories. The isotopic plots suggested influences from evaporation. The saturation indices for gypsum and calcite indicated equilibrium conditions are consistent with historical geological processes in the region. Continuous monitoring and further studies are recommended to develop effective groundwater management strategies in response to ongoing salinization challenges caused by natural behavior.

关键词： Hypersaline groundwater numerical modeling Seawater intrusion Evapotranspiration Groundwater chemistry

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numerical modeling for the degradation rate of hydrocarbon-based proton exchange membrane at different current densities in water electrolysis

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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 2025年 127卷 179-188页

作者： Lee, Chang Jin Oh, Keun-Hwan Song, Jaeheon Ham, Hyeong Deok Kim, Tae-Ho Yu, Duk Man Lee, Sang-Young Yoon, Sang Jun So, Soonyong Korea Res Inst Chem Technol KRICT Hydrogen Energy Res Ctr Daejeon 34114 South Korea Yonsei Univ Dept Chem & Biomol Engn Seoul 03722 South Korea Hanyang Univ Dept Organ & Nano Engn Seoul 04763 South Korea Chungnam Natl Univ Dept Polymer Sci & Engn 99 Daehak Ro Daejeon 34134 South Korea

Proton exchange membrane water electrolysis (PEMWE) is a promising technology for producing green hydrogen using renewable energy sources, such as solar and wind power. Given the intermittent nature of these energy sources, PEMWE systems must operate under fluctuating loads, ranging from low to high current densities. Conventional PEMs, specifically perfluorinated sulfuric acid (PFSA) membranes, are widely used in PEMWE systems. However, their high gas permeability can constrain low current density operation and generate high levels of hydroxyl radicals, leading to membrane degradation. As such, hydrocarbon-based PEMs, with their lower H2 and O2 permeability, present themselves as attractive alternatives for PEMWE applications. Most studies emphasize that due to their low gas permeability, hydrocarbon-based PEMs offer benefits in expanding the operating current range and reducing the production rate of hydroxyl radicals, which are crucial for enhancing durability under fluctuating loads. However, many studies on hydrocarbon-based PEMs overlook the membrane degradation rate constant. This study addresses this gap by experimentally measuring the rate constant of membrane degradation and incorporating it into a numerical model for PEM degradation. Based on the modeling results, a hydrocarbon-based PEM requires reinforcement by a chemically stable porous support to lower the degradation rate constant and gas crossover. Therefore, reinforcing hydrocarbon-based PEMs with a chemically stable porous support presents a plausible design direction to utilize them for water electrolysis applications.

关键词： Proton exchange membrane water electrolysis Degradation rate PFSA Hydrocarbon-based PEM numerical modeling

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numerical modeling of Reinforcement Solutions in Traditional Stone Masonry Using a Particle Model

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BUILDINGS 2025年第7期15卷 1058-1058页

作者： Azevedo, Nuno Monteiro Cismasiu, Ildi Pinho, Fernando F. S. Neves, Filipe Lab Nacl Engn Civil LNEC Concrete Dams Dept P-1700066 Lisbon Portugal CERIS P-2829516 Caparica Portugal FCT NOVA NOVA Sch Sci & Technol Dept Civil Engn P-2829516 Caparica Portugal FCT NOVA NOVA Sch Sci & Technol Dept Civil Engn P-2829516 Caparica Portugal

Traditional stone masonry walls are structural elements in most historic buildings. To preserve them and improve their ability to withstand extreme events, such as earthquakes, it is necessary to implement effective reinforcement solutions. This paper presents the modeling of traditional Portuguese rubble stone masonry walls, reinforced with external steel mesh, sprayed micro-concrete layers and transverse confinement by steel connectors, which were developed and tested experimentally in uniaxial compression. The modeling is carried out using micro-modeling through a 2D particle model (PM). The process of calibrating the properties of both micro-concrete and concrete is presented, the methodology for generating the numerical models is described and the numerical response is compared with the experimental results. The numerical results show that the PM can adequately reproduce the experimentally observed behavior of this type of reinforcement solution.

关键词： traditional stone masonry walls strengthening solution micro-concrete layer uniaxial compression tests numerical modeling particle model

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