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Simulation of the deformable lateral boundaries in biaxial test using dEM

Particuology 2024年第5期88卷 161-175页

作者： Ali Momeni Barry Clarke Yong Sheng Ali Hassanpour WSP 3 Wellington PlaceLeedsLS1 4APUK Hull University HullHU6 7RXUK School of Civil Engineering University of LeedsLeedsLS2 9JTUK School of Computer Science University of HullHullHU6 7RXUK School of Chemical and Process Engineering University of LeedsLeedsLS2 9JTUK

Applying the discrete element method(dEM)in soil mechanics can provide abundant information at the particle-scale and facilitates illustration of the macro-mechanical behaviour of soils based on the inter-particle *** triaxial test is one of the most common laboratory methods to study the macro-mechanical behaviour of particulate materials such as ***,many problems in geotechnical design can be assumed and simplified as a plane strain *** a biaxial test can be conducted to reproduce the macro-mechanical behaviour of soil,where the sample is enclosed by two horizontal rigid platens and a vertical latex membrane,which is a deformable continuous element and allows the enclosed specimen to deform freely while maintaining confining stress during *** paper presents an algorithm to represent physical and mechanical characteristics of latex membrane in the 2d dEM simulation of biaxial test using the PFC^(2d) *** investigate the impact of the lateral boundary conditions on the micro-macro mechanical behaviours of soil samples,two sets of dEM biaxial tests are conducted,*** rigid and deformable lateral boundary *** dEM modeling results indicate that the lateral boundary conditions have a significant effect on the micro-scale fabric properties,thickness and inclination of the shear *** comparison between these two simulations also demonstrates that the lateral boundary conditions play a major role in the peak and post-peak stress-strain behaviours as well as the dilation and critical state behaviours of granular soils.

关键词： discrete element method Biaxial test deformable boundaries Shear band Critical state Fabric anisotropy Geometrical stability index

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Web Application Commercial design for Financial Entities Based on Business Intelligence

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Computers, Materials & Continua 2021年第6期67卷 3177-3188页

作者： Carlos Andrés Tavera romero Jesus Hamilton Ortiz Osamah Ibrahim Khalaf Andrea ríos Prado COMBA I+d research Group of Universidad Santiago de Cali Valle del CaucaColombia closemobile r&d telecommunications ls FuenlabradaEspaña Al-Nahrain Nanorenewable Energy research Center in Al-Nahrain University BagdadIraq

Multiple customer data management has become a focus of attention in big *** much information is available,it does not translate into significant profitable value-added *** present a design of a commercial web application based on business intelligence that generates information on social and financial behavior of clients in an organization;with the purpose of obtain additional information that allows to get more *** app will provide a broader perspective for making strategic decisions to increase profits and reduce internal investment costs.A case in point is the financial sector,a group of financial entities were used to make measurements and test them.A design to build a web application aimed at achieving a large and ambitious goal by means of defined tools reflecting clients’business needs is *** this research,different techniques and technologies are explored,such as diagrams,frameworks,design,architecture,model entity-relationship,tables,equations,mental maps and development *** the Personal Software Process methodology and with the help of information extraction,consolidation,and visualization,the implementation can be carried *** article provides the importance of implementing business intelligence in an organization and expands on the steps needed for the implementation of this valuable technology.

关键词： Business intelligence banking application web application trend analysis decision making

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Gradient-induced long-range optical pulling force based on photonic band gap

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Light(Science & Applications) 2024年第5期13卷 865-874页

作者： Wenlong Lu Alexey V.Krasavin Sheng Lan Anatoly V.Zayats Qiaofeng dai Guangdong Basic research Center of Excellence for Structure and Fundamental Interactions of Matter Guangdong Provincial Key Laboratory of Nanophotonic Functional Materials and DevicesSchool of Information and Optoelectronic Science and EngineeringSouth China Normal UniversityGuangzhou 510006China department of Physics and London Centre for Nanotechnology King’s College LondonLondon WC2R 2LSUK

Optical pulling provides a new degree of freedom in optical *** is generally believed that long-range optical pulling forces cannot be generated by the gradient of the incident ***,we theoretically propose and numerically demonstrate the realization of a long-range optical pulling force stemming from a self-induced gradient field in the manipulated *** analogy to potential barriers in quantum tunnelling,we use a photonic band gap design in order to obtain the intensity gradients inside a manipulated object placed in a photonic crystal waveguide,thereby achieving a pulling *** the usual scattering-type optical pulling forces,the proposed gradient-field approach does not require precise elimination of the reflection from the manipulated *** particular,the Einstein-Laub formalism is applied to design this unconventional gradient *** magnitude of the force can be enhanced by a factor of up to 50 at the optical resonance of the manipulated object in the waveguide,making it insensitive to *** developed approach helps to break the limitation of scattering forces to obtain longrange optical pulling for manipulation and sorting of nanoparticles and other *** developed principle of using the band gap to obtain a pulling force may also be applied to other types of waves,such as acoustic or water waves,which are important for numerous applications.

关键词： optical waveguide scattering

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Optimal Center-of-Mass Pivot Effect of Spinal Motion in Feline Galloping

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Journal of Bionic Engineering 2020年第5期17卷 970-977页

作者： Young Kook Kim dongwon Yun LV r&d team Electro-technology R&D CenterLS ELECTRIC Co.LtdCheongju 28437South Korea department of robotics Engineering Daegu Gyeongbuk Institute of Science and Technology(DGIST)Daegu 42988South Korea

In this paper,we studied the acceleration behavior of a quadruped animal during a galloping *** the development of many quadruped robotic systems has been focused on dynamic movements,it is obvious that guidance from the dynamic behavior of quadruped animals is needed for robotics *** fulfill this demand,this paper deals with analysis of the galloping motions of a domestic cat,which is well known for its excellent acceleration performance among four-legged *** on the planar motion capture environment,the movement data of a galloping feline was acquired and the dynamic motions were estimated using a spring-mass *** particular,the effects of the position and angle of the center-of-mass of the cat,angular displacement of the spine,and angular velocity of the spine were analyzed and are discussed *** this process,it was possible to understand the dynamic movement characteristics of the cat,and to understand the relationships between,and the influences of,these *** this analysis,we provide significant data applicable to the design of joint movements in quadruped robot systems.

关键词： quadrupedalism feline galloping domestic cat center-of-mass

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QoS in FANET Business and Swarm data

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Computers, Materials & Continua 2022年第7期72卷 1877-1899页

作者： Jesús Hamilton Ortiz Carlos Andrés Tavera romero Bazil Taha Ahmed Osamah Ibrahim Khalaf Close Mobile r&d telecommunications ls MadridEspaña COMBA I+d research Group of Universidad Santiago de Cali CaliColombia Autonomous of Madrid University MadridEspaña Al-Nahrain Nanorenewable Energy research Center in Al-Nahrain University BagdadIraq

This article shows the quality of services in a wireless swarm of drones that form an ad hoc network between them Fly Ad Hoc Networks(FANET).Each drone has the ability to send and receive information(like a router);and can behave as a hierarchical node whit the intregration of three protocols:Multiprotocol Label Switch(MPls),Fast Hierarchical Ad Hoc Mobile(FHAM)and Internet Protocol version 6(IPv6),in conclusion MPls+FHAM+*** metrics analyzed in the FANET are:delay,jitter,throughput,lost and sent packets/*** process was carried out with swarms composed of 10,20,30 and 40 units;In this work,the stage with 40 droneswas analyzed showing registration processes,and sentmessages sequences between different drones that were part of the same swarm.A special analysis about the traffic between drones(end-to-end)was carried out,as well as the possible security flaws in each drone and the current status and future trends in real *** future trends,in a real environment,we took as a starting point,metrics results obtained in the simulation(positive according to the obtained results).These results gave us a clear vision of how the network will behave in a real environment with the aim to carry out the experiment on a physical level in the near *** work also shows the experience quality from the service quality metrics obtained through a mathematical *** quality of experience model will allow us to use it objectively in the agricultural sector,which is a great interest area and is where we are working with *** in this article we show our advances for a business model applied to the aforementioned agricultural sector,as well as the data analysis and services available to the end *** services available to the end customer have been classified into a basic,medium,advanced and plus level.

关键词： Ad hoc home agent(AHA) ad hoc mobile node(AMN) ad hoc correspondent node(ACN) ad hoc mobile anchor point(AMAP) fast hierarchical Ad hoc mobile IPv6(FHAMIPv6) label switching router(lsr)label edge router(LEr) mobile ad hoc networks(MANET)fly ad hoc network(FANET) quality of services(QoS) quality of experience(QoE)

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A combined experimental and dEM investigation of grain interlocking in sheared granular assemblies

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Particuology 2024年第7期90卷 436-451页

作者： rui Lu Qiang Luo Tengfei Wang david P.Connolly Tao Xie School of Civil Engineering Southwest Jiaotong UniversityChengdu 610031China Key Laboratory of High-Speed railway Engineering(Southwest Jiaotong University) Ministry of EducationChengdu 610031China School of Civil Engineering University of LeedsLeeds LS29JTUK department of Civil Engineering McMaster UniversityHamiltonONCanada

Compacted granular material,integral to geotechnical engineering,undergoes translation,rotation,and interlocking when subject to shear displacements or external *** present study focuses on the interlocking of heterogeneous granular materials,a complex behavior influenced by gradation,compaction,and varying particle geometry,and has consequently received limited attention in existing *** address this research gap,we conducted an analysis on the effect of grain interlocking on the shear resistance of granular assemblies,using a combination of laboratory testing and the discrete element method(dEM).Initially,large-scale direct shear tests were conducted on gravel−sand mixes with varying degrees of compaction and normal *** of the mixes also underwent subsequent shear reversal to explore the differences in grain interlocking between the two shearing processes on the shear *** analyzing the laboratory results,a mesoscopic scale investigation was performed by replicating the test using discrete element *** facilitate this,granular particle geometries were measured using 3d laser scanning based on the physical lab ***,based on these scans,discrete element r-block and ball models were utilized to construct both the coarse and fine particles within the *** vibro-compaction was employed to regulate the degree of *** results indicate that an increase in vertical pressure,coupled with a zero dilatancy angle,results in a rising stress ratio,indicative of grain *** interlocking exhibits a positive correlation with both the coarse content and the degree of compaction,and varies depending on the shear *** interlocking progresses,the shear band,induced by particle movement,expands and is associated with reduced particle rotation near the shear *** study further reveals a consistent positive correlation between interlocking and the principal orientation angle of strong normal c

关键词： Granular material Interlocking Shear resistance direct shear discrete element method Vibro-compaction

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design Improvements and Validation of a Novel Fully 3d Printed Analogue Lumbar Spine Motion Segment

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Journal of Bionic Engineering 2024年第3期21卷 1388-1396页

作者： Siril Teja dukkipati Mark driscoll Musculoskeletal Biomechanics research Lab Department of Mechanical EngineeringMcGill University845 Sherbrooke St.W(163)MontréalQCH3A 0C3Canada Orthopaedic research Lab Montreal General Hospital1650 Cedar Ave(LS1.409)MontréalQCH3G 1A4Canada

Spine biomechanical testing methods in the past few decades have not evolved beyond employing either cadaveric studies or finite element modeling ***,both these approaches may have inherent cost and time *** studies are the present gold standard for spinal implant design and regulatory approval,but they introduce significant variability in measurements across patients,often requiring large sample *** element modeling demands considerable expertise and can be computationally expensive when complex geometry and material nonlinearity are *** analogue spine models could complement these traditional methods as a low-cost and high-fidelity alternative.A fully 3d printable L-S1 analogue spine model with ligaments is developed and validated in this *** stiffness of the model under pure bending loading in flexion-extension,Lateral Bending(LB)and Axial rotation(Ar)is evaluated and compared against historical ex vivo and in silico ***,the effect of interspinous,intertransverse ligaments and the Thoracolumbar Fascia(TLF)on spinal stiffness is evaluated by systematic construction of the *** flexion,model range of Motion(rOM)was 12.92±0.11°(ex vivo:16.58°,in silico:12.96°)at *** LB,average rOM was 13.67±0.12°at 7.5 Nm(ex vivo:15.21±1.89°,in silico:15.49±0.23°).Similarly,in Ar,average rOM was 17.69±2.12°at 7.5Nm(ex vivo:14.12±0.31°,in silico:15.91±0.28°).The addition of interspinous and intertransverse ligaments increased both flexion and LB stiffnesses by approximately 5%.Addition of TLF showed increase in flexion and Ar stiffnesses by 29%and 24%,*** novel model can reproduce physiological rOMs with high repeatability and could be a useful open-source tool in spine biomechanics.

关键词： Lumbar spine 3d printing Intervertebral disc Biomechanical testing Spine mechanics

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Numerical analysis of high‑speed railway slab tracks using calibrated and validated 3d time‑domain modelling

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railway Engineering Science 2024年第1期32卷 36-58页

作者： A.F.Esen O.Laghrouche P.K.Woodward d.Medina‑Pineda Q.Corbisez J.Y.Shih d.P.Connolly Institute for High‑Speed rail and System Integration University of LeedsLeeds LS29JTUK Institute for Infrastructure and Environment Heriot-Watt UniversityEdinburgh EH144ASUK Alstom Transport Saint‑OuenFrance Birmingham Centre for railway research and Education University of BirminghamBirmingham B152TTUK

Concrete slabs are widely used in modern railways to increase the inherent resilient quality of the tracks,provide safe and smooth rides,and reduce the maintenance *** this paper,the elastic performance of a novel slab trackform for high-speed railways is investigated using three-dimensional finite element modelling in *** is then compared to the performance of a ballasted ***,slab and ballasted track models are developed to replicate the full-scale testing of track *** the models are calibrated with the experimental results,the novel slab model is developed and compared against the calibrated slab track *** slab and ballasted track models are then extended to create linear dynamic models,considering the track geodynamics,and simulating train passages at various speeds,for which the Ledsgard documented case was used to validate the *** travelling at low and high speeds are analysed to investigate the track deflections and the wave propagation in the soil,considering the issues associated with critical *** train loading methods are discussed,and the most practical approach is retained and ***,correlations are made between the geotechnical parameters of modern high-speed rail and conventional *** is found that considering the same ground condition,the slab track deflections are considerably smaller than those of the ballasted track at high speeds,while they show similar behaviour at low speeds.

关键词： High-speed railways Slab track New ballastless track Ballasted track Critical speeds Finite element modelling Calibration of numerical models

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Biomimetic Quadruped robot with a Spinal Joint and Optimal Spinal Motion via reinforcement Learning

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Journal of Bionic Engineering 2021年第6期18卷 1280-1290页

作者： Young Kook Kim Woojin Seol Jihyuk Park LV r&d Team Electro-technology R&D CenterLS Electric Co.LtdCheongju28437Republic of Korea digital Innovation Unit Korea Hydro&Nuclear Power Co.Ltd1312-gil YuseongdaeroYusung-guDaejeon34101Republic of Korea department of Automotive Engineering College of Mechanical and IT EngineeringYeungnam University280 Daehak-roGyeongsanGyeongbuk38541Republic of Korea

Feline animals can run quickly using spinal joints as well as the joints that make up their four *** paper describes the development of a quadruped robot including a spinal joint that biomimics feline *** developed robot platform consists of four legs with a double 4-bar linkage type and one simplified rotary *** addition,Q-learning,a type of machine learning,was used to find the optimal motion profile of the spinal *** bounding gait was implemented on the robot system using the motion profile of the spinal joint,and it was confirmed that using the spinal joint can achieve a faster Center of Mass(CoM)forward speed than not using the spinal *** the motion profile obtained through Q-learning did not exactly match the spinal angle of a feline animal,which is more multiarticular than that of the developed robot,the tendency of the actual feline animal spinal motion profile,which is sinusoidal,was similar.

关键词： Quadruped robot system Bioinspired methods Legged robots Machine learning Q-learning

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Multicriteria Analysis by Codification for the determination of Soil Landscape Units in Forest and Pre-Forest Zones of Cote d’Ivoire: The Case of the Square degrees of M’Bahiakro and daloa

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International Journal of Geosciences 2024年第1期15卷 12-24页

作者： Guy Fernand Yao derving Baka Koffi Emmauel Kassin Bala Mamadou Ouattara Nestor Kouman Yao Kouakou Kouadio Amani Jean Lopez Essehi Brou Kouame Albert Yao-Kouame National Agricultural research Center (CNrA) Central Laboratory Soils Water and Plants (LCSEP) Sustainable Soil Management and Water Control Program Bouaké Ivory Coast Earth Sciences and Mining resources Training and research Unit (UFr STrM) Soil Water and Geomaterials Sciences Laboratory (LS2EG) Félix Houphou&#235t-Boigny University Cocody-Abidjan Abidjan C&#244te d’Ivoire Mondelez International Abidjan C&#244te d’Ivoire Training and research Unit (UFr) Communication Environment and Society Department of Geography University Alassane Ouattara Bouaké C&#244te d’Ivoire Soil Water and Geomaterials Sciences Laboratory (LS2EG) Earth Sciences and Mining Resources Training and Research Unit (UFR STRM) Félix Houphou&#235t-Boigny University Abidjan Ivory Coast

The present study, carried out in the forest (daloa) and pre-forest (M’Bahiakro) zones of Cote d’Ivoire, aims to determine soil landscape units using the coding method. Geological maps and satellite images (SrTM and Landsat) were used for this purpose. The methodological approach adopted consisted in producing maps of slope, geology, land use and topography using the codification method. These various maps, integrated into a GIS using the coding aggregation method, were used to generate soil landscape maps. Twenty-seven (27) soil landscapes have been identified for the pre-forest zone (M’Bahiakro), with a strong dominance of acid rock over a moderate relief under savannah, forest/degraded forest and crops/fallow. However, the forest zone (daloa), with forty-one (41) soil landscapes identified over the entire zone, is characterized by a majority of mafic rocks on a medium altitude under forest/degraded forest, water and crops/fallow. The criteria used from the codification method (sum of aggregations) made it possible to predict the spatial distribution of soil map units according to agro-ecological environments in the humid intertropical zone. This is essential for the orientation and reinforcement of soil survey tools. However, a comparative evaluation of the different multicriteria analysis methods for coding and weighting soil landscape unit mapping would enable us to identify the most suitable and efficient method for drawing up base maps for soil surveys.

关键词： GIS Multicriteria Analysis by Coding Soil Landscapes daloa M’Bahiakro Cote d’Ivoire

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