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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

Deep Synchronization Control of Grid-Forming Converters:A Reinforcement Learning Approach

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IEEE/CAA Journal of Automatica Sinica 2025年第1期12卷 273-275页

作者： Zhuorui Wu Meng Zhang Bo Fan Yang Shi Xiaohong Guan the School of Cyber science and engineering Xi'an Jiaotong University the department of mechanical engineering University of Victoria

Dear Editor,This letter proposes a deep synchronization control(DSC) method to synchronize grid-forming converters with power grids. The method involves constructing a novel controller for grid-forming converters based on the stable deep dynamics model. To enhance the performance of the controller, the dynamics model is optimized within the deep reinforcement learning(DRL) framework. Simulation results verify that the proposed method can reduce frequency deviation and improve active power responses.

关键词： Deep reinforcement learning

Free vibration and transient response of double curved beams connected by intermediate straight beams

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applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 37-62页

作者： R.A.JAFARI-TALOOKOLAEI H.GHANDVAR E.JUMAEV S.KHATIR T.CUONG-LE School of mechanical engineering Babol Noshirvani University of Technology department of mechanical engineering Faculty of Engineering New Uzbekistan University University of Business and science Center for engineering Application and Technology Solutions Ho Chi Minh City Open University

This paper investigates the free vibration and transient response of interconnected structures including double curved beams and intermediate straight beams,which are all constructed from functionally graded porous(FGP) materials. The strain potential and kinetic energies of each beam along with the work done by the external force are calculated. Additionally, a higher-order beam element is introduced to derive stiffness and mass matrices, along with the force vector. The curved and straight beams are discretized, and their assembled stiffness, mass matrices, and force vectors, are *** conditions at the joints are used to derive the total matrices of the entire structure. Subsequently, the natural frequencies and transient response of the system are determined. The accuracy of the mathematical model and the self-developed computer program is validated through the comparison of the obtained results with those of the existing literature and commercial software ANSYS, demonstrating excellent ***, a comprehensive study is conducted to investigate the effects of various parameters on the free vibration and transient response of the considered structure.

关键词： double curved beam finite element method functionally graded porous (FGP) material intermediate straight beam O313 vibration analysis

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

Atomically precise M-N-C electrocatalysts for oxygen reduction:Effects of inter-site distance,metal-metal interaction,coordination environment,and spin states

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Journal of Energy Chemistry 2025年第2期101卷 132-155页

作者： Junfeng Huang Saira Ajmal Anuj Kumar Jianwen Guo Mohammed Mujahid Alam Abdullah G.Al-Sehemi Ghulam Yasin School of mechanical engineering Dongguan University of Technology Nano-Technology Research Laboratory Department of Chemistry GLA University department of Chemistry College of Science King Khalid University School of Environmental science and engineering Tianjin University State Key Laboratory of Chemical Resource engineering College of Materials Science and Engineering Beijing University of Chemical Technology

Inspired by molecular catalysts,researchers developed atomically precise nitrogen-coordinated single or dual metal sites imbedded in graphitized carbon（M-N-C） to fully utilize metallic sites for *** catalysts performed remarkably well in the electrocatalytic oxygen reduction reaction（ORR） due to their distinct coordination and electrical structures,Nonetheless,their maximum efficacy in practical applications has yet to be *** agenda identifies tailoring the coordination environment,spin states,intersite distance,and metal-metal interaction as innovative approaches to regulate the ORR performance of these ***,it is necessary to undertake a precise assessment of these methodologies and the knowledge obtained to be implemented in the design of future M-N-C catalysts for ***,this review aims to analyze recent progress in M-N-C ORR catalysts,emphasizing their innovative engineering with aspects such as alteration in intersite distance,metal-metal interaction,coordination environment,and spin ***,we critically discuss how to logically monitor the atomic structure,local coordination,spin,and electronic states of M-N-C catalysts to modulate their ORR *** have also highlighted the challenges associated with M-N-C catalysts and proposed suggestions for their future design and fabrication.

关键词： Activity descriptors Electrocatalysis M-N-C electrocatalysts ORR Spin states

Flow field distribution and overpressure characteristics inside the crew compartment of a truck-mounted howitzer under the effect of muzzle blast

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Defence Technology(防务技术) 2025年第2期44卷 190-205页

作者： Shengcheng Wei Linfang Qian Yadong Xu Qiang Yin Xinyu Xiong School of mechanical engineering Nanjing University of Science and TechnologyNanjing210094China Northwest Institute of mechanical and Electrical engineering Xianyang712099China

The muzzle blast overpressure induces disturbances in the flow field inside the crew compartment(FFICC)of a truck-mounted howitzer during the artillery *** overpressure is the primary factor preventing personnel from firing artillery within the *** investigate the overpressure characteristics of the FFICC,a foreign trade equipment model was used as the research object,and a numerical model was established to analyze the propagation of muzzle blast from the muzzle to the interior of the crew compartment under extreme firing *** comparative verification,the muzzle blast experiment included overpressure data from both the flow field outside the crew compartment(FFOCC)and the FFICC,as well as the acceleration data of the crew compartment structure(Str-CC).The research findings demonstrate that the overpressure-time curves of the FFICC exhibit multi-peak characteristics,while the pressure wave shows no significant *** enclosed nature of the cab hinders the dissipation of pressure wave energy within the FFICC,leading to sustained high-amplitude *** frameskin structure helps attenuate the impact of muzzle blast on the ***,local high overpressure caused by the convex or concave features of the cab's exterior significantly amplifies the overpressure amplitude within the FFICC.

关键词： Truck-mounted howitzer Muzzle blast Flow field inside the crew compartment(FFICC) Overpressure characteristics Flow-structure interaction

Data-Driven Healthcare:The Role of Computational Methods in Medical Innovation

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Computer Modeling in engineering & sciences 2025年第1期142卷 1-48页

作者： Hariharasakthisudhan Ponnarengan Sivakumar Rajendran Vikas Khalkar Gunapriya Devarajan Logesh Kamaraj department of mechanical engineering Dr.Mahalingam College of Engineering and TechnologyPollachiCoimbatoreTamil Nadu642003India department of mechanical engineering JKKN College of Engineering and TechnologyKumarapalayamNamakkalTamil Nadu637209India department of mechanical engineering Gharda Institute of TechnologyLavelMaharashtra415708India department of Electrical and Electronics engineering Sri Eshwar College of EngineeringCoimbatoreTamilnadu641202India department of mechanical engineering Vel Tech Rangarajan Dr.Sagunthala R&D Institute of Science and TechnologyChennai600062India

The purpose of this review is to explore the intersection of computational engineering and biomedical science,highlighting the transformative potential this convergence holds for innovation in healthcare and medical *** review covers key topics such as computational modelling,bioinformatics,machine learning in medical diagnostics,and the integration of wearable technology for real-time health *** findings indicate that computational models have significantly enhanced the understanding of complex biological systems,while machine learning algorithms have improved the accuracy of disease prediction and *** synergy between bioinformatics and computational techniques has led to breakthroughs in personalized medicine,enabling more precise treatment ***,the integration of wearable devices with advanced computational methods has opened new avenues for continuous health monitoring and early disease *** review emphasizes the need for interdisciplinary collaboration to further advance this *** research should focus on developing more robust and scalable computational models,enhancing data integration techniques,and addressing ethical considerations related to data privacy and *** fostering innovation at the intersection of these disciplines,the potential to revolutionize healthcare delivery and outcomes becomes increasingly attainable.

关键词： Computational models biomedical engineering bioinformatics machine learning wearable technology

Nonlinear forced vibration in a subcritical regime of a porous functionally graded pipe conveying fluid with a retaining clip

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applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 101-122页

作者： M.GHOLAMI M.EFTEKHARI department of mechanical engineering Shahid Bahonar University of Kerman

This study examines the nonlinear behaviors of a clamped-clamped porous pipe made of a functionally graded material(FGM) that conveys fluids and is equipped with a retaining clip, focusing on primary resonance and subcritical dynamics. The nonlinear governing equations for the FGM pipe are derived by the extended Hamilton's principle, and subsequently discretized through the application of the Galerkin *** direct method of multi-scales is then used to solve the derived equations. A thorough analysis of various parameters, including the clip stiffness, the power-law index, the porosity, and the clip location, is conducted to gain a comprehensive understanding of the system's nonlinear dynamics. Through the analysis of the first natural frequency, the study highlights the influence of the flow velocity and the clip stiffness, while the comparisons with metallic pipes emphasize the role of FGM composition. The examination of the forced response curves reveals saddle-node bifurcations and their dependence on parameters such as the detuning parameter and the power-law index, offering valuable insights into the system's nonlinear resonant behavior. Furthermore, the frequency-response curves illustrate the hardening nonlinearities influenced by factors such as the porosity and the clip stiffness, revealing nuanced effects on the system response and resonance characteristics. This comprehensive analysis enhances the understanding of nonlinear behaviors in FGM porous pipes with a retaining clip, providing key insights for practical engineering applications in system design and optimization.

关键词： functionally graded material (FGM) pipe conveying fluid O175.2 porosity primary resonance retaining clip subcritical regime

Numerical Simulation of Radiation Transport to Improve Microalgae Cultivation in an Air-Lift Photobioreactor

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Journal of Thermal science 2025年第1期34卷 62-76页

作者： ZHANG Xianbin LI Mingjia HUNG Tzuchen ZHANG Zixun Key Laboratory of Thermo-Fluid science and engineering of Ministry of Education School of Energy and Power EngineeringXi'an Jiaotong UniversityXi'an 710049China School of mechanical engineering Beijing Institute of TechnologyBeijing 100081China department of mechanical engineering Taipei University of TechnologyTaipei 106344China

A comprehensive numerical model is developed to simulate the growth of microalgae under light/dark cycling *** purpose of this study is to predict the growth rate of Chlorella vulgaris cultivated in photobioreactors(PBRs)in order to improve the light conditions for microalgae and enhance the photosynthetic *** fluid dynamics(CFD)is used to simulate its internal hydrodynamic *** Lagrangian method is employed to track the movement of microalgae *** radiative transfer equation(RTE)is used to obtain light intensity *** combination of light radiation field and microalgae cell motions is used to construct the light history and they are integrated into the model of the photosynthetic units(PSU)to calculate the microalgae growth *** numerical results demonstrate that enhanced light/dark cycling frequency with ordered mixing can promote efficient microalgae *** effect of the vortex flow field generated by the baffles in an air-lift PBR is analyzed for increasing microalgae growth *** using the 1:1 baffle spacing,the biomass production of microalgae is increased by 41.8% compared to the original PBR.

关键词： photobioreactor light distribution particle tracking structure optimization