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A Simplified Method for the Stress Analysis of Underground transfer Structures Crossing Multiple Subway tunnels

Computer Modeling in Engineering & Sciences 2024年第6期139卷 2893-2915页

作者： Shen Yan Dajiang Geng Ning Dai Mingjian Long Zhicheng Bai College of Civil Engineering Tongji UniversityShanghai200092China China Construction 4th Engineering Bureau 6th Corp. Ltd.Shanghai201199China Department of Civil and Architecture Engineering Hubei Polytechnic UniversityHuangshi435003China

According to the design specifications,the construction of extended piles involves traversing the tunnel’s upper region and extending to the underlying rock *** address this challenge,a subterranean transfer structure spanning multiple subway tunnels was *** on the function of piles in the transfer structure as springs with axial and bending stiffness,and taking into account the force balance and deformation coordination conditions of beams and plates within the transfer structure,we established a simplified mechanical model that incorporates soil stratification by combining it with the Winkler elastic foundation beam *** resolved established simplifiedmechanicalmodel employed finite difference technology and the Newton-Simpsonmethod,elucidating the mechanical mechanism of the transfer *** research findings suggest that the load carried by the upper structural columns can be transferred to the pile foundation beneath the beams through the transfer structure,subsequently reaching the deep soil layer and ensuring minimal impact on adjacent *** established simplified analysis method can be used for stress analysis of the transfer structure,concurrently considering soil stratification,pile foundation behavior,and plate *** pile length,pile section size,and beam section size within the transfer structure should account for the characteristics of the upper load,ensuring an even distribution of the beam bending moment.

关键词： Crossing tunnels transfer structure force mechanism simplify analysis layered soil mass

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tribological properties of Al-GNP composites at elevated temperature

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Friction 2024年第5期12卷 1028-1041页

作者： Sunil POUDEL Rizwan BAJWA Yongde XIA Zakir KHAN Yi ZHANG Yanqiu ZHU College of Engineering Mathematics and Physical SciencesUniversity of ExeterExeterEX44QFUK European technical Centre Daido Metal Co.Ltd.Iliminster SomersetTA199PHUK

Lighter and more powerful next generation vehicles and other rotary machinery demand bearings to operate in harsher conditions for higher efficiency,and the continuous development of advanced low-wear and friction materials is thus becoming even more important to meet these *** aluminium composites reinforced with high performance lubricate phases such as graphene nanoplatelets(GNPs)are very promising and have been vigorously *** maintaining a low coefficient of friction(COF)and offering great strength against wear due to their self-lubricating capability,the solid lubricant like GNPs protect the bearing surface from wear damage and prevent change in metallurgical properties during temperature *** paper first studies the high-temperature tribological performance of aluminium matrix composites reinforced with GNP,consolidated via powder metallurgy,then elucidates their tribological *** report that the best tribological performance is achieved by the composite containing 2.0 wt%GNP,with an extraordinarily low COF of 0.09 and a specific wear rate of 3.5×10^(−2)mm^(3)·N^(−1)·m^(−1),which represent 75%and 40%reduction respectively,against the plain aluminium consolidated under identical *** in-track and out-of-track Raman analysis have confirmed the role of GNPs in creating a tribofilm on the counterpart surface which contributed to the excellent performance.

关键词： nanocomposite graphene nanoplatelet(GNP) tribology powder metallurgy

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Prediction of the undrained shear strength of remolded soil with non-linear regression,fuzzy logic,and artificial neural network

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Journal of Mountain Science 2024年第9期21卷 3108-3122页

作者： YÜNKÜL Kaan KARAÇOR Fatih GÜRBÜZ Ayhan BUDAK tahsinÖmür Department of Civil Engineering Faculty of Engineering and ArchitectureTokat Gaziosmanpaşa UniversityTokat 60100Türkiye Department of Civil Engineering Faculty of Engineering and ArchitectureKafkas UniversityKars 36000Türkiye Department of Civil Engineering Faculty of EngineeringGazi UniversityAnkara 06570Türkiye Ministry of Youth and Sports Ankara 06090Türkiye

this study aims to predict the undrained shear strength of remolded soil samples using non-linear regression analyses,fuzzy logic,and artificial neural network modeling.A total of 1306 undrained shear strength results from 230 different remolded soil test settings reported in 21 publications were collected,utilizing six different measurement *** water content,plastic limit,and liquid limit were used as input parameters for fuzzy logic and artificial neural network modeling,liquidity index or water content ratio was considered as an input parameter for non-linear regression *** non-linear regression analyses,12 different regression equations were derived for the prediction of undrained shear strength of remolded ***-Forward backpropagation and the tANSIG transfer function were used for artificial neural network modeling,while the Mamdani inference system was preferred with trapezoidal and triangular membership functions for fuzzy logic *** experimental results of 914 tests were used for training of the artificial neural network models,196 for validation and 196 for *** was observed that the accuracy of the artificial neural network and fuzzy logic modeling was higher than that of the non-linear regression ***,a simple and reliable regression equation was proposed for assessments of undrained shear strength values with higher coefficients of determination.

关键词： Undrained shear strength Liquidity index Water content ratio Non-linear regression Artificial neural networks Fuzzy logic

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Approximate contact solutions for non-axisymmetric homogeneous and power-law graded elastic bodies:A practical tool for design engineers and tribologists

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Friction 2024年第2期12卷 340-355页

作者： valentin L.POPOv Qiang LI Emanuel WILLERt Institute of Mechanics Technische Universität BerlinBerlin 10623Germany

In two recent papers,approximate solutions for compact non-axisymmetric contact problems of homogeneous and power-law graded elastic bodies have been suggested,which provide explicit analytical relations for the force–approach relation,the size and the shape of the contact area,as well as for the pressure distribution *** solutions were derived for profiles,which only slightly deviate from the axisymmetric *** the present paper,they undergo an extensive testing and validation by comparison of solutions with a great variety of profile shapes with numerical solutions obtained by the fast Fourier transform(FFt)-assisted boundary element method(BEM).Examples are given with quite significant deviations from axial symmetry and show surprisingly good agreement with numerical solutions.

关键词： normal contact non-axisymmetric indenter extremal principle generalized method of dimensionality reduction(MDR) functional elastic grading

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Research on Indoor Positioning technology of WSN based on t-RL Partition Path Model

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Journal of Communications and Information Networks 2024年第3期9卷 219-232页

作者： Wei Wang Xinlin Wang Yutong Liu Yulin Ren Maozhen Li Asoke K.Nandi School of Information and Communication Engineering North University of ChinaTaiyuan 030051China Department of Electronic and Computer Engineering Brunel University LondonUxbridge UB83PHUK

to address the issues of unstable received signal strength indicator(RSSI)and low indoor positioning accuracy caused by walls and obstacles,the propagation conditions of the wireless communication system are categorized into two distinct environments:line-of-sight(LOS)and non-line-of-sight(NLOS).In the LOS environment,the traditional logarithmic path loss model is *** the NLOS environment,the impact of walls on signal transmission is considered,leading to the development of a multi-wall path loss model based on the t-RL method,with improvements made to the key parameter,the Fresnel coefficient *** breakpoint value d=2.3 m in the partitioned model is determined,and the positional coordinates of the unknown nodes are calculated using the trilateration *** results indicate that the t-RL based multi-wall model improves localization accuracy by 47%in NLOS environments compared to the traditional logarithmic path loss *** average localization error using the t-RL partitioned path loss model is 0.7021 m,representing a 55.9%improvement over the logarithmic path loss model and a 16.8%enhancement over the t-RL attenuation multi-wall model,thereby providing better environmental adaptability.

关键词： WSN indoor positioning loss model reflection transmission RSSI

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Design of Resilient Sensor Networks Balancing Resilience and Efficiency

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International Journal of Disaster Risk Science 2024年第1期15卷 107-115页

作者： Sergey N.vecherin Kiril D.Ratmanski Luke Hogewood Igor Linkov Cold Regions Research and Engineering Laboratory Engineering Research and Development CenterHanoverNH 03755USA Environmental Laboratory Engineering Research and Development CenterVicksburgMS 39180USA

In recent years,the notion of resilience has been developed and applied in many technical areas,becoming exceptionally pertinent to disaster risk *** a disaster situation,accurate sensing information is the key to efficient recovery *** general,resilience aims to minimize the impact of disruptions to systems through the fast recovery of critical functionality,but resilient design may require redundancy and could increase *** this article,we describe a method based on binary linear programming for sensor network design balancing efficiency with *** application of the developed framework is demonstrated for the case of interior building surveillance utilizing infrared sensors in both twoand three-dimensional *** method provides optimal sensor placement,taking into account critical functionality and a desired level of resilience and considering sensor type and *** problem formulation,resilience requirements,and application of the optimization algorithm are described in *** of sensor locations with and without resilience requirements shows that resilient configuration requires redundancy in number of sensors and their intelligent *** tasks are successfully solved by the described method,which can be applied to strengthen the resilience of sensor networks by *** proposed methodology is suitable for large-scale optimization problems with many sensors and extensive coverage areas.

关键词： Binary linear programming Optimal sensor placement Redundant networks Resilience and efciency Resilient sensor networks

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Dynamic thermal performance of multilayer hollow clay walls filled with insulation materials:toward energy saving in hot climates

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Energy and Built Environment 2024年第1期5卷 70-80页

作者： Yassine Chihab Mohammed Garoum Najma Laaroussi Mohammed v University in Rabat MaterialsEnergy and Acoustics TEAMRabatMorocco

this study examines the benefits of incorporating passive techniques into multilayer hollow clay brick walls to improve their dynamic thermal *** finite element approach was used to solve the incompressible Navier-Stokes and energy equations to analyze the dynamic thermal response of walls exposed to real thermal excitations of the Marrakesh *** results show that increasing the emissivity from 0.1 to 0.9 significantly increases the total heat load over 24 ***,filling 100% of the cavities with insulation materials delayed the temperature peak by about 2.3 h and lowered the decrement factor by roughly 43%,with a value smaller than *** addition,it is demonstrated that the total thermal load is reduced by approximately 28% for improved wall configurations(100% insulation filling cavities)compared to traditional wall configurations(100% air filling cavities),which aids in improving building energy efficiency.

关键词： time lag Decrement factor Coupled heat transfer Analytical solution Hollow clay brick Insulation filling cavities Energy savings in building

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A simulation study on spatial and time resolution for a cost-effective positron emission particle tracking system

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Particuology 2024年第5期88卷 312-322页

作者： Josephine Oppotsch Matthias Steinke Miriam Fritsch Fritz-Herbert Heinsius thomas Held Nikoline Hilse viktor Scherer Ulrich Wiedner Ruhr-Universität Bochum Institut für Experimentalphysik I44801 BochumGermany Ruhr-Universität Bochum Lehrstuhl für Energieanlagen und Energieprozesstechnik44801 BochumGermany

this work is the second part of a simulation study investigating the processing of densely packed and moving granular assemblies by positron emission particle tracking (PEPt).Since medical positron emission tomography (PEt) scanners commonly used for PEPt are very expensive,a PEt-like detector system based on cost-effective organic plastic scintillator bars is being developed and tested for its *** this context,the spatial resolution of a resting positron source,a source moving on a freely designed model path,and a particle motion given by a discrete element method (DEM) simulation is studied using Monte Carlo simulations and the software toolkit *** not only extended the simulation and reconstruction to a moving source but also significantly improved the spatial resolution compared to previous work by adding oversampling and iteration to the reconstruction ***,in the case of a source following a trajectory developed from DEM simulations,a very good resolution of about 1 mm in all three directions and an average 3D deviation between simulated and reconstructed events of 2.3 mm could be ***,the resolution for realistic particle motion within the generic grate system (which is the test rig for further experimental studies) is well below the smallest particle *** simulation of the dependence of the reconstruction accuracy on tracer particle location revealed a nearly constant efficiency within the entire detector system,which demonstrates that boundary effects can be neglected.

关键词： Positron emission particle tracking Monte Carlo method time-of-flight Plastic scintillators Silicon photomultipliers(SiPMs)

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A simulation study for a cost-effective PEt-like detector system intended to track particles in granular assemblies

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Particuology 2024年第1期84卷 117-125页

作者： Josephine Oppotsch Antonios Athanassiadis Miriam Fritsch Fritz-Herbert Heinsius thomas Held Nikoline Hilse viktor Scherer Matthias Steinke Ulrich Wiedner Ruhr-Universität Bochum Institut für Experimentalphysik I44801 BochumGermany Ruhr-Universität Bochum Lehrstuhl für Energieanlagen und Energieprozesstechnik44801 BochumGermany

Since many industrial applications rely on the processing of densely packed and moving granular ma-terial,obtaining bulk internal information on the particle movement inside the reactors is of great *** information can be delivered by Positron Emission Particle tracking(PEPt).By marking pellets with a positron-emitting radioisotope,the position of these tracer particles can be determined via the time-of-flight differences of the emitted gamma-ray *** current paper proposes a PEt-like detector system based on cost-effective organic plastic scintillators instead of the more common but expensive inorganic *** system is currently under construction and was tested for its resolution and efficiency in this simulation *** Monte Carlo simulations and the software toolkit Geant4,three different geometries(an empty glass box,a generic grate system,and a cubic box of 1 m3 completely filled with pellets)were investigated,leading to a spatial resolution in the millimeter range and an efficiency,defined as the ratio of reconstructed decay locations to simulated decays,of 2.7%,1.4%,and 0.3%.

关键词： Positron emission particle tracking Geant4 Monte Carlo method time-of-flight Plastic scintillators Silicon photomultipliers(SiPMs)

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Role of End-ring Configuration in Shaping IE4 Induction Motor Performance

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CES transactions on Electrical Machines and Systems 2024年第3期8卷 245-254页

作者： tayfun Gundogdu Sinan Suli Istanbul technical University Energy InstituteMaslak/İstanbulTürkiye and GAMAK Electric MotorsDudullu OSB34775Ümraniye/İstanbulTürkiye GAMAK Electric Motors Dudullu OSB34775Ümraniye/İstanbulTürkiye

the performance characteristics,particularly the starting performance of direct line-fed induction motors,which are mainly influenced by the design of the rotor,are crucial considerations for *** is quite a challenging issue for motor manufacturers to enhance the starting performance of existing mass-produced motors with minimal modifications and *** this paper,a simple and cost-effective method to improve the starting performance of a commercial squirrel-cage induction motor(SCIM)is *** influence of geometric parameters of the end-ring on the performance characteristics,including starting(locked rotor)torque,pull-up and break down torque,starting current,rotor electric parameters,current density,power losses,and efficiency have been comprehensively *** has been revealed that among the other end-ring design parameters,the ring thickness has a significant effect on the performance *** optimal end-ring thickness is determined,and its performance characteristics have been compared to those of its initial *** and parametric analyses have been conducted using a 2D time-stepping finite element method(FEM).the FEM results were validated using experimental measurements obtained from an 11 kW SCIM prototype.

关键词： End-ring design Induction motor Starting performance Super premium efficiency torque-speed curve

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