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Si-C Foam Porous-Medium Combustion Power-Generation System for Low-Calorific-Value Biomass Syngas

Journal of Thermal Science 2025年第1期34卷 206-222页

作者： YANG Jianwen CHEN Wei CAO Bingwei LIU Xinhui LI Hang College of mechanical and aerospace engineering Jilin UniversityChangchun 130025China School of mechanical and Vehicle engineering Changchun UniversityChangchun 130022China

Syngas produced from the gasification of organic feedstocks from biomass is one of the clean and sustainable sources of *** advantages of simple access and renewability of biomass energy can meet the energy needs of temporary power *** study presents a biomass power-generation system for vehicular *** biomass and a free-piston Stirling engine generator(FPSEG)as the primary material and prime mover,respectively,biomass energy is converted into electricity by combusting the syngas to heat the *** and key parameter design for biomass gasification and thermoelectric conversion systems within a power generation system were performed.A porous medium area was constructed using Si-C foam ceramics to obtain an energy-conversion experimental *** effects of bed height,porosity,porous-region diameter,and air-intake conditions on the power-generation performance were investigated,and optimisations were performed for the thermoelectric conversion *** rate of increase during FPSEG power generation first increased and then decreased with increasing bed height,peaking at a bed height of 40 *** increasing porous-region diameter accelerated FPSEG power generation,whereas porosity changes in the porous media did not significantly affect the rate of change during FPSEG power *** increasing air intake,the rate of increase during power generation first increased and then *** maximum change rate and the highest thermoelectric conversion efficiency of the power-generation system occurred at 9.5 m^(3)/h and 6.5 m^(3)/h(~45.1%)air intakes,*** the thermal inertia and combustion structure of the thermoelectric conversion system significantly increased the power-generation rate of the system,with 1.8 W/s being observed at a 9.7 m^(3)/h air intake.

关键词： biomass gasification combined heat and power(CHP) porous media combustion power generation

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Target Search and Navigation in Heterogeneous Robot Systems with Deep Reinforcement Learning

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Machine Intelligence Research 2025年第1期22卷 79-90页

作者： Yun Chen Jiaping Xiao Department of mechanical engineering University of AlabamaTuscaloosa35487USA School of mechanical and aerospace engineering Nanyang Technological UniversitySingapore639798Singapore

Collaborative heterogeneous robot systems can greatly enhance the efficiency of target search and navigation *** this paper,we design a heterogeneous robot system consisting of an unmanned aerial vehicle(UAV)and an unmanned ground vehicle(UGV)for search and rescue missions in unknown *** system is able to search for targets and navigate to them in a maze-like mine environment with the policies learned through deep reinforcement learning *** the training process,if two robots are trained simultaneously,the rewards related to their collaboration may not be properly ***,we introduce a multi-stage reinforcement learning framework and a curiosity module to encourage agents to explore unvisited *** in simulation environments show that our framework can train the heterogeneous robot system to achieve the search and navigation with unknown target locations while existing baselines may *** UGV achieves a success rate of 89.1%in the mission within the original environment,and maintains a 67.6%success rate in untrained complex environments.

关键词： Heterogeneous intelligent systems deep reinforcement learning multiagent systems robot learning target search

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Dynamic modeling of a three-dimensional braided composite thin plate considering braiding directions

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 123-138页

作者： Chentong GAO Huiyu SUN Jianping GU W.M.HUANG College of aerospace engineering Nanjing University of Aeronautics and Astronautics School of mechanical and aerospace engineering Nanyang Technological University Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology School of Materials Science and EngineeringNanjing Institute of Technology

Currently, there are a limited number of dynamic models available for braided composite plates with large overall motions, despite the incorporation of three-dimensional(3D) braided composites into rotating blade components. In this paper, a dynamic model of 3D 4-directional braided composite thin plates considering braiding directions is established. Based on Kirchhoff's plate assumptions, the displacement variables of the plate are expressed. By incorporating the braiding directions into the constitutive equation of the braided composites, the dynamic model of the plate considering braiding directions is obtained. The effects of the speeds, braiding directions, and braided angles on the responses of the plate with fixed-axis rotation and translational motion, respectively, are investigated. This paper presents a dynamic theory for calculating the deformation of 3D braided composite structures undergoing both translational and rotational motions. It also provides a simulation method for investigating the dynamic behavior of non-isotropic material plates in various applications.

关键词： braiding direction composite thin plate dynamic model large overall motion O313.7 three-dimensional (3D) braided composite

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Inferring Evanescent Stochastic Dynamics from Marginal Distributions

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Journal of Systems Science & Complexity 2025年第01期 129-149页

作者： ELDESOUKEY Asmaa MIANGOLARRA Olga Movilla GEORGIOU Tryphon T. Depatment of mechanical and aerospace engineering University of California Irvine

Evanescent random walks are instances of stochastic processes that terminate at a specific rate. They have proved relevant in modeling diverse behaviors of complex systems from protein degradation in gene networks(Ali and Brewster(2022), Ghusinga, et al.(2017), and Ham, et al.(2024)) and“nonprocessive” motor proteins(Kolomeisky and Fisher(2007)) to decay of diffusive radioactive matter(Zoia(2008)). The present work aims to extend a well-established estimation and control problem, the so-called Schr?dinger's bridge problem, to evanescent diffusion processes. Specifically, the authors seek the most likely law on the path space that restores consistency with two marginal densities — One is the initial probability density of the flow, and the other is a density of killed particles. The Schr?dinger's bridge problem can be interpreted as an estimation problem but also as a control problem to steer the stochastic particles so as to match specified marginals. The focus of previous work in Eldesoukey, et al.(2024) has been to tackle Schr?dinger's problem involving a constraint on the spatio-temporal density of killed particles, which the authors revisit here. The authors then expand on two related problems that instead separately constrain the temporal and the spatial marginal densities of killed *** authors derive corresponding Schr?dinger systems that contain coupled partial differential equations that solve such problems. The authors also discuss Fortet-Sinkhorn-like algorithms that can be used to construct the sought bridges numerically.

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Dynamic stress concentration in an infinitely long cylindrical cavity due to a point spherical source embedded within a fluid-saturated poroelastic formation of infinite extent

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 139-156页

作者： H.HOSSEINI O.BALILASHAKI Department of mechanical engineering Faculty of EngineeringGolestan University

The effects of a harmonically exciting monopole source on an infinitely long cylindrical cavity embedded entirely within a fluid-saturated poroelastic formation of infinite extent are examined theoretically. It is assumed that the source is located outside the cavity at a specified distance from the borehole axis. The magnitudes of the hoop and radial stresses beside the pore pressures exerted on the interface and inside the porous medium surrounding the borehole are calculated and discussed. Biot's poroelastic modeling along with three types of boundary conditions for the cylindrical interface including the ideal fluid, empty borehole, and rigid inclusion with a hard boundary is employed for the analysis. Utilizing a proper translational addition theorem for expressing the incident spherical wave in terms of cylindrical wave expansions, the proposed boundary conditions at the interface are satisfied. Stresses are formulated by means of wave potential functions in a three-dimensional(3D) manner. The effects of the frequency and the radial distance between the source and borehole on the induced stresses are examined for the first cylindrical modes over frequency spectra. Two permeability conditions for the interface and three types of soils for the porous formation are considered throughout the analysis. To give an overall outline of the study, a numerical example is presented. The results clearly indicate that the distance is a key parameter and has considerable effects on the induced stress values. In addition, the interface permeability condition and soil characteristics play an important role in determining the dynamic response of the borehole. Finally,the obtained results are compared with the relevant analyses existing in the literature for some limit cases, and good agreement is achieved.

关键词： cylindrical cavity O353.4 point source porous medium stress concentration wave-field transformation

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Mach reflection and pressure/heating loads on V-shaped blunt leading edges with variable cross-sections and crotches

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Chinese Journal of Aeronautics 2025年第1期38卷 271-285页

作者： Tao ZHANG Xuhui ZHANG Luoyu RAO Chongguang SHI Chengxiang ZHU Yancheng YOU School of aerospace engineering Xiamen UniversityXiamen 361005China China Academy of aerospace Science and Innovation Beijing 100176China

The primary Mach Reflection(MR)and pressure/heating loads on V-shaped Blunt Leading Edges(VBLEs)with variable elliptic cross-sections and conic crotches are theoretically investigated in this *** simplified continuity method is used to forecast the shock *** theoretical predictions and the numerical simulations for the Mach stem and the triple point as well as the curved shock accord *** on the theoretical model,an analysis of the impact of the axial ratio a/b of the cross-sectional shape and the eccentricity e of the crotch sweep path on shock structures is carried *** shock configurations obtained from the theoretical model enable the derivation of the transition boundaries between the primary MR and the same family Regular Reflection(sRR).It is found that the increase of a/b and e can both facilitate the primary MR to sRR *** resulting transition and the corresponding generation of the wall pressure and heat flux are then *** results indicate that higher values of the ratio a/b can significantly reduce the wall pressure and heating loads by inducing the primary MR to sRR ***,the increase in the eccentricity e results in increased loads,despite causing the same transition.

关键词： Aerodynamics Hypersonic flow Shock waves Heat flux V-shaped blunt leading edges

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Effects of bidirectional interaction on inelastic seismic response:When is its effect significant?

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Earthquake engineering and engineering Vibration 2025年第1期24卷 113-134页

作者： Atanu Santra Rana Roy Department of aerospace engineering and Applied Mechanics Indian Institute of Engineering Science and TechnologyShibpur 711103India

Motivated by the early works on bidirectional interaction and the breakthrough to estimate seismic response to bidirectional shaking via unidirectional analysis,it is essential to answer the question:When is the interaction effect significant?Early works concluded that the effect of interaction is pronounced for stiff systems;consequently,the straightforward method for estimating seismic response to bidirectional excitation by using unidirectional analyses is verified primarily for short period ***,it is essential to identify the domain of significance for bidirectional interaction before adopting this simple methodology in *** parametrically defined systems with elastoplastic and degrading hysteresis models are studied under near-fault motions,assuming strength-independent and strength-dependent *** force-based and displacement-based analyses,conducted in parallel,reveal that the interaction effect is considerable for stiff systems,especially with degrading characteristics in a relatively low inelasticity ***,the bidirectional effect may be significant even for highly flexible systems,especially for residual deformation,which in earlier works was *** range of significance depends on the hysteresis model,system parameters,and response *** analysis is carried out with the results of the case studies,and the derived regression models may be used for a preliminary assessment of the impact of interaction in advance.

关键词： bidirectional residual forward-directive fling force-based displacement-based regression

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Combined anisotropic and cyclic constitutive model for laser powder bed fusion fabricated aluminum alloy

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Chinese Journal of Aeronautics 2025年第1期38卷 165-184页

作者： Fei-Fan LI Jihong ZHU Weihong ZHANG Shifeng WEN Jingwen SONG Jun MA Gang FANG State IJR Center of aerospace Design and Additive Manufacturing School of Mechanical EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518063China School of Materials Science and engineering Northwestern Polytechnical UniversityXi'an 710072China Department of mechanical and Industrial engineering Norwegian University of Science and TechnologyTrondheim 7491Norway State Key Laboratory of Tribology in Advanced Equipment Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China

This study presents new methods to effectively model the anisotropic yielding and hardening behavior of laser powder bed fusion fabricated aluminum alloy under both monotonic and cyclic loading *** proposed model combines the yield surface-interpolation method to accurately describe the anisotropic hardening rates in various directions,with the Chaboche kinematic hardening rule to precisely reflect the cyclic *** numerical implementation of the combined anisotropic and cyclic constitutive model,a fully implicit stress integration algorithm based on return mapping method is ***,the multiple parameters associated with the model are categorized and identified in an uncoupled *** isotropic and cyclic hardening parameters are determined by an inverse method,and the stability of the optimization outcomes is validated by applying different starting points for the ***,the back-stress effect on the identification of anisotropic parameters associated with the stress invariant-based Hill48 yield function is considered for the first *** consideration leads to an improved prediction accuracy compared to the identification of anisotropic parameters without considering back-stress *** combined anisotropic and cyclic constitutive model,along with the calibrated parameters,are proven capable of accurately reproducing the intricate deformation behavior of laser powder bed fusion fabricated AlSi10Mg.

关键词： Constitutive models Anisotropy Kinematic hardening Laser powder bed fusion Aluminum alloys

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Comparative Evaluation and Performance Analysis of Heat Exchangers Featured with Peened Surface

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Journal of Thermal Science 2025年第1期34卷 50-61页

作者： DINESHBABU Chinnadurai SHIVA SANKARAN Nallasamy VENKATESH RAJAKrishnan VENKATESH Rathinavelu Department of mechanical engineering Kongunadu College of Engineering and TechnologyTamil Nadu-621215India Department of mechanical engineering Selvam College of TechnologyNamakkalTamil Nadu-637003India Department of mechanical engineering Sona College of TechnologySalemTamil Nadu-636005India Department of mechanical engineering Saveetha School of EngineeringSaveetha Institute of Medical and Technical Sciences(SIMATS)Saveetha UniversityChennai 602105TamilnaduIndia

Heat exchangers have the potential for various engineering applications,and their performance is enriched by surface *** proposed system enriches the heat exchanger's performance by adapting a peened stainless steel(SS)surface blasted with copper,grinding,sand,and *** influences peened SS surface modified with a copper blast,grinding,sandblast,and iron blast on the surface morphology of shell and tube heat exchanger surface(STHE)is analyzed via tungsten heated cathode electron gun featured scanning electron microscope and observed coarse grain *** SS surface featured STHE performance is experimentally evaluated by different flow rates(30,60,90,and 120 L/min)underwater fluid medium functioned by the temperature ranges of 25-75℃ and its results are compared with computational fluid dynamic(CFD)/heat transfer research(HTRI)analyzed *** 60 L/min flow rate was spotted as an optimum value for both shell and tube side *** STHE is operated with a 60 L/min flow rate under the different peened surfaces and evaluated its Stanton number,Nusselt number,logarithmic mean temperature difference(LMTD),overall heat transfer coefficient,number of transfer units(NTU),effectiveness,and exergy *** iron blasted SS peened surface was observed to have better SHTE performance like Stanton number(0.0012),Nusselt number(2180),reduced LMTD of 31℃,improved overall heat transfer co-efficient of 2400 W/(m^(2)·K),better NTU of 0.5532,good effectiveness value of 0.45162,and hiked exergy efficiency of 10% respectively.

关键词： penned surface performance analysis stainless steel shell and tube heat exchanger

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Ultrasonic vibration-assisted cutting of titanium alloys:A state-of-the-art review

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Chinese Journal of Aeronautics 2025年第1期38卷 3-42页

作者： Ahmar KHAN Xin WANG Biao ZHAO Wenfeng DING Muhammad JAMIL Aqib Mashood KHAN Syed Hammad ALI Sadam HUSSAIN Jiong ZHANG Raj DAS National Key Laboratory of Science and Technology on Helicopter Transmission Nanjing University of Aeronautics and AstronauticsNanjing 210016China Department of mechanical engineering College of EngineeringCity University of Hong KongHong Kong 999077China Centre for Additive Manufacturing School of EngineeringAerospace Engineering and AviationRMIT UniversityVictoria 3083Australia

The remarkable ability of titanium alloys to preserve their superior physical and chemical characteristics when subjected to extreme conditions significantly enhances their importance in the aerospace,military,and medical ***,conventional machining of titanium alloys leads to elevated tool wear,development of surface defects,and reduced machining efficiency due to their low heat conductivity,and chemical *** issues can be somewhat counteracted by integrating ultrasonic vibration in the conventional machining of titanium alloys and also enhance *** review article offers a holistic evaluation of the influence of ultrasonic vibration-assisted milling and turning on cutting forces,temperature,tool wear,and surface integrity,encompassing surface morphology,surface roughness,surface residual stress,surface hardness,and surface tribological properties during titanium alloys ***,it investigates the sustainability aspect that has not been previously *** on the performance of ultrasonic-assisted cutting revealed several advantages,including decreased cutting forces and cutting temperature,improved tool life,and a better-machined surface during ***,the sustainability factor is improved due to minimized energy consumption and residual *** conclusion,the key challenges and future prospects in the ultrasonic-assisted cutting of titanium alloys are also *** review article provides beneficial knowledge for manufactur-ers and researchers regarding ultrasonic vibration-assisted cutting of titanium alloy and will play an important role in achieving sustainability in the industry.

关键词： Ultrasonic vibration-assisted cutting Titanium alloys Material removal mechanism Machinability Sustainability

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