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World Journal of Mechanics 2024年第5期14卷 73-96页

作者： David W. A. Rees Abdelraouf M. sami Alsheikh College of Engineering and Design Brunel University Uxbridge UK

Three aluminium channel sections of US standard extruded dimension are mounted as cantilevers with x-axis symmetry. The flexural bending and shear that arise with applied axial torsion are each considered theoretically and numerically in terms of two longitudinal axes of loading not coincident with the shear centre. in particular, the warping displacements, stiffness and stress distributions are calculated for torsion applied to longitudinal axes passing through the section’s centroid and its web centre. The stress conversions derived from each action are superimposed to reveal a net sectional stress distribution. Therein, the influence of the axis position upon the net axial and shear stress distributions is established compared to previous results for each beam when loading is referred to a flexural axis through the shear centre. Within the net stress analysis is, it is shown how the constraint to free warping presented by the end fixing modifies the axial stress. The latter can be identified with the action of a ‘bimoment’ upon each thin-walled section.

关键词： Thin-Aluminium Channels Cantilever Beam Bending Shear Torsion Warping Bimoment Flexural Axis Centre of Twist Centroid Shear Centre Torsional Stiffness Constrained Stress

Theory of Flexural Shear, Bending and Torsion for a Thin-Walled Beam of Open Section

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World Journal of Mechanics 2024年第3期14卷 23-53页

作者： David W. A. Rees Abdelraouf M. sami Alsheikh College of Engineering and Design Brunel University Uxbridge UK

Aspects of the general Vlasov theory are examined separately as applied to a thin-walled channel section cantilever beam under free-end end loading. in particular, the flexural bending and shear that arise under transverse shear and axial torsional loading are each considered theoretically. These analyses involve the location of the shear centre at which transverse shear forces when applied do not produce torsion. This centre, when taken to be coincident with the centre of twist implies an equivalent reciprocal behaviour. That is, an axial torsion applied concentric with the shear centre will twist but not bend the beam. The respective bending and shear stress conversions are derived for each action applied to three aluminium alloy extruded channel sections mounted as cantilevers with a horizontal principal axis of symmetry. Bending and shear are considered more generally for other thin-walled sections when the transverse loading axes at the shear centre are not parallel to the section = s centroidal axes of principal second moments of area. The fixing at one end of the cantilever modifies the St Venant free angular twist and the free warping displacement. it is shown from the Wagner-Kappus torsion theory how the end constrained warping generates an axial stress distribution that varies with the length and across the cross-section for an axial torsion applied to the shear centre. it should be mentioned here for wider applications and validation of the Vlasov theory that attendant papers are to consider in detail bending and torsional loadings applied to other axes through each of the centroid and the web centre. Therein, both bending and twisting arise from transverse shear and axial torsion applied to each position being displaced from the shear centre. Here, the influence of the axis position upon the net axial and shear stress distributions is to be established. That is, the net axial stress from axial torsional loading is identified with the sum of axial stress

关键词： Thin Wall Theory Cantilever Beam Open Channel Section Principal Axes Flexure Transverse Shear Torsion Shear Centre Shear Flow Warping Fixed-End Constraint

Zircon U-Pb-Hf and trace element signatures reveal the petrogenesis of the Jiuyishan granitic complex， South China: implications for W-Sn and rare metal mineralization

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Journal of Earth Science 2024年

作者： Wenzhou Xiao Chaoyun Liu Kaixuan Tan Xianzhe Duan Qinglin Sui Kaituo Shi Peng Feng Mabrouk sami Quan Ou Hunan Key Laboratory of Rare Metal Minerals Exploitation and Geological Disposal of Wastes， School of Resource Environment and Safety Engineering， University of South China Fundamental Science on Radioactive Geology and Exploration Technology Laboratory， East China University of Technology Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring， Ministry of Education， School of Geosciences and info-Physics， Central South University Geology Department， Faculty of Science， Minia University State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation， institute of Sedimentary Geology， Chengdu University of Technology

The Jiuyishan granitic complex， located in the Nanling Range， South China， is composed of five granitic plutons （Xuehuading， Jinjiling， Pangxiemu， Shaziling and Xishan）. Zircon U-Pb dating of four plutons （Jinjiling， Pangxiemu， Shaziling and Xishan） yielded similar ages of approximately 153 Ma， indicating indistinguishable ages within error. Three plutons except the Shaziling pluton， have consistent εNd（t）（-7.8 to -5.8） and εHf（t）（-9.1 to -2.2） values， which are similar to those of the lower crustal granulitic metasedimentary and meta-igneous rocks in South China. Comparing to other three plutons， the Shaziling pluton has consistent εHf（t）（-7.4 to -6.8） and εHf（t）（-7.5 to -4.7） values and shows similar source， but the Shaziling mafic microgranular enclaves （MMEs） show variable εHf（t）（-14.2 to 4.8） values， indicating a remarkable mantle magma injection of the Shaziling pluton. Zircon Ce/Sm-Yb/Gd， whole-rock CaO-P2O5and CaO-TiO2linear trends revealed that from the Xishan to the Shaziling and from the Jinjiling to the Pangxiemu granites， they experienced apatite and titanite fractionation， respectively. Zircon Th， U， Nb， Ta， Hf， Ti， Y， P and rare earth element （REE） contents and whole-rock Sr， Ba and Rb contents also show that the Shazling， Xishan， Jinjiling and Pangxiemu granites followed a discontinuous evolutionary series， but the Pangxiemu granites exhibit highly evolved nature. Four main controlling factors of W-Sn and rare metal mineralization in granitic rocks were discussed， and we found that the mineralization in Jiuyishan granitic complex was mainly controlled by the fractionation degree and crystallization temperature， but were rarely affected by oxygen fugacity and mantle material input. The Pangxiemu granites show particularly higher Rb and Ta contents than the other three plutons， implying that the ore deposits developed in the Jiuyishan complex were directly related to the most evolved Pangxiemu pluton， with the occurrence of Rb and Ta as the most l

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Survival and risk analysis of patients with COViD-19 in iran

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Journal of Acute Disease 2024年第2期13卷 60-66页

作者： Mottaghipoor F Heidari Z sami R Memarzadeh H Saghaeiannejad isfahani S Department of Management and Health information Technology Isfahan University of Medical SciencesIsfahanIran Department of Biostatistics and Epidemiology Isfahan University of Medical SciencesIsfahanIran Department of internal Medicine School of MedicineIsfahan University of Medical SciencesIsfahanIran Software Engineering Isfahan University of Medical SciencesIsfahanIran Health information Technology Research Center Isfahan University of Medical SciencesIsfahanIran

Objective:To evaluate the risk factors of death caused by COViD-19 in ***:This study was a retrospective cohort study from February 20,2020,to August 22,2022,in the hospitals in isfahan,*** data were collected through a researcher-made *** determine the risk factors of the death,logistic regression and Cox regression models were *** each variable,the odds ratio and 95%confidence interval were also ***:1885 Patients were *** age of deceased persons was significantly higher than that of the surviving *** risk of death for the age group above 60 years was about 14 times higher than that of people aged 19-35 years[95%Ci:14.41(2.02-102.99),Pion[95%Ci:1.92(1.47-2.5),Piabetes[95%Ci:1.62(1.23-2.13),Pic obstructive pulmonary disease[95%Ci:1.92(1.47-2.50),Pisk factors of ***:This study reveals that the mortality rate due to COViD-19 is associated with old age,longer hospitalization in the iCU,increased length of stay,and comorbidities of high blood pressure,diabetes,and chronic pulmonary disease.

关键词： Cause Death Survival COViD-19 Risk factors iran

Analysis of Mobile and internet Network Coverage: Propagation of Electromagnetic Waves and Concept of Digital Divide in Burundi

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Open Journal of Antennas and Propagation 2024年第1期12卷 1-18页

作者： Apollinaire Bigirimana Jérémie Ndikumagenge sami Tabbane Romeo Nibitanga Hassan Kibeya Center for Research in infrastructure Environment and Technology (CRIET) Doctoral School of the University of Burundi Bujumbura Burundi Center for Research in infrastructure Environment and Technology (CRIET) University of Burundi Bujumbura Burundi Higher School of Communications of Tunis Technological City of Communications Ariana Tunisia Faculty of Engineering Sciences Universit du Burundi Bujumbura Burundi

Mobile and internet network coverage plays an important role in digital transformation and the exploitation of new services. The evolution of mobile networks from the first generation (1G) to the 5th generation is still a long process. 2G networks have developed the messaging service, which complements the already operational voice service. 2G technology has rapidly progressed to the third generation (3G), incorporating multimedia data transmission techniques. it then progressed to fourth generation (4G) and LTE (Long Term Evolution), increasing the transmission speed to improve 3G. Currently, developed countries have already moved to 5G. in developing countries, including Burundi, a member of the East African Community (ECA) where more than 80% are connected to 2G technologies, 40% are connected to the 3G network and 25% to the 4G network and are not yet connected to the 5G network and then still a process. The objective of this article is to analyze the coverage of 2G, 3G and 4G networks in Burundi. This analysis will make it possible to identify possible deficits in order to reduce the digital divide between connected urban areas and remote rural areas. Furthermore, this analysis will draw the attention of decision-makers to the need to deploy networks and coverage to allow the population to access mobile and internet services and thus enable the digitalization of the population. Finally, this article shows the level of coverage, the digital divide and an overview of the deployment of base stations (BTS) throughout the country to promote the transformation and digital inclusion of services.

关键词： Coverage of Mobile Networks and internet Digital Divide Rural and isolated Areas Antenna Connectivity and Digital inclusion

Design Study of a Cable-based Gait Training Machine

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Journal of Bionic Engineering 2017年第2期14卷 232-244页

作者： Houssein Lamine Med Amine Laribi sami Bennour Lotfi Romdhane said Zeghloul Mechanical Laboratory of Sousse (LMS) National Engineering School of Sousse University of Sousse Sousse 4000 Tunisia Department of GMSC Pprime Institute CNRS ENSMA University of Poitiers UPR 3346 France Mechanical Engineering Department American University of Sharjah PO Box 26666 Sharjah United Arab Emirates

This paper deals with a design approach of a gait training machine based on a quantitative gait analysis. The proposed training machine is composed of a body weight support device and a cable-driven parallel robot. This paper is focused on the cable-driven robot, which controls the pose of the lower limb through an orthosis placed on the patient＇s leg. The cable robot reproduces a normal gait movement through the motion of the orthosis. A motion capture system is used to perform the quantitative analysis of a normal gait, which will be used as an input to the inverse dynamic model of the cable robot. By means of an optimization algorithm, the optimal design parameters, which minimize the tensions in the cables, are determined. Two constraints are considered, i.e., a non-negative tension in the cables at all times, and a free cable/end-effector collision. Once the optimal solution is computed, a power analysis is carried out in order to size the robot actuators. The proposed approach can be easily extended for the design study of a similar type of cable robots.

关键词： gait rehabilitation cable-driven robots body weight support system design optimization

Enhanced Heap-Based Optimizer Algorithm for Solving Team Formation Problem

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Computers, Materials & Continua 2022年第12期73卷 5245-5268页

作者： Nashwa Nageh Ahmed Elshamy Abdel Wahab said Hassan Mostafa sami Mustafa Abdul Salam Faculty of Science Suez Canal UniversityIsmailiaEgypt Faculty of Computers and Artificial intelligence Helwan UniversityHelwanEgypt Faculty of Computers and Artificial intelligence Benha UniversityBenha 13518Egypt Faculty of Computer Studies Arab Open UniversityCairoEgypt

Team Formation(TF)is considered one of the most significant problems in computer science and *** is defined as forming the best team of experts in a social network to complete a task with least *** real-world problems,such as task assignment,vehicle routing,nurse scheduling,resource allocation,and airline crew scheduling,are based on the TF *** has been shown to be a Nondeterministic Polynomial time(NP)problem,and high-dimensional problem with several local optima that can be solved using efficient approximation *** paper proposes two improved swarm-based algorithms for solving team formation *** first algorithm,entitled Hybrid Heap-Based Optimizer with Simulated Annealing Algorithm(HBOSA),uses a single crossover operator to improve the performance of a standard heap-based optimizer(HBO)*** also employs the simulated annealing(SA)approach to improve model convergence and avoid local minima *** second algorithm is the Chaotic Heap-based Optimizer Algorithm(CHBO).CHBO aids in the discovery of new solutions in the search space by directing particles to different regions of the search *** HBO’s optimization process,a logistic chaotic map is *** performance of the two proposed algorithms(HBOSA)and(CHBO)is evaluated using thirteen benchmark functions and tested in solving the TF problem with varying number of experts and ***,the proposed algorithms were compared to well-known optimization algorithms such as the Heap-Based Optimizer(HBO),Developed Simulated Annealing(DSA),Particle SwarmOptimization(PSO),GreyWolfOptimization(GWO),and Genetic Algorithm(GA).Finally,the proposed algorithms were applied to a real-world benchmark dataset known as the internet Movie Database(iMDB).The simulation results revealed that the proposed algorithms outperformed the compared algorithms in terms of efficiency and performance,with fast convergence to the global minimum.

关键词： Team formation problem optimization problem genetic algorithm heap-based optimizer simulated annealing hybridization method chaotic local search

Space Division Multiple Access for Cellular V2X Communications

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Computers, Materials & Continua 2022年第10期73卷 1195-1206页

作者： Doaa sami Khafaga Mohammad Zubair Khan Muhammad Awais Javed Amel Ali Alhussan Wael said Department of Computer Sciences College of Computer and Information SciencesPrincess Nourah bint Abdulrahman UniversityP.O.Box 84428Riyadh11671Saudi Arabia Department of Computer Science and information Taibah University Madinah Saudi Arabia Department of Electrical and Computer Engineering COMSATS University Islamabad45550Pakistan Department of Computer Science Faculty of Computers and InformaticsZagazig UniversityZagazig44511Egypt

Vehicular communication is the backbone of future intelligent Transportation Systems(iTS).it offers a network-based solution for vehicle safety,cooperative awareness,and traffic management *** safety applications,Basic Safety Messages(BSM)containing mobility information is shared by the vehicles in their neighborhood to continuously monitor other nearby vehicles and prepare a local traffic *** are shared using mode 4 of Cellular V2X(C-V2X)communications in which resources are allocated in an ad hoc ***,the strict packet transmission requirements of BSM and hidden node problem causes packet collisions in a vehicular network,thus reducing the reliability of safety ***,as vehicles choose the transmission resources in a distributed manner in mode 4 of CV2X,the packet collision problem is further *** paper presents a novel solution in the form of a Space Division Multiple Access(SDMA)protocol that intelligently schedules BSM transmissions using vehicle position data to reduce concurrent transmissions from hidden node *** proposed protocol works by dividing road segments into clusters and *** sub-frames are allocated to a cluster and these sub-frames are reused after a certain *** a cluster,sub-channels are allocated to *** implement the proposed SDMA protocol and evaluate its performance in a highway vehicular *** results show that the proposed SDMA protocol outperforms standard Sensing-Based Semi Persistent Scheduling(SB-SPS)in terms of safety range and packet delay.

关键词： iTS vehicular network cellular V2X SDMA

Modeling the Spatio-Temporal Dynamics of Local Context for a Contextualized Diffusion of Agroecological intensification Options in Niger

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international Journal of Geosciences 2024年第3期15卷 270-301页

作者： Nouhou Salifou Jangorzo Maud Loireau Abou-Souﬁanou Sadda Ousmane sami Mari Abdoul-Aziz Saïdou Hassane Bil-Assanou issoufou Département des Sciences du Sol et Télédétection Université Dan Dicko Dankoulodo de Maradi UMR DAP Maradi Niger Unité mixte de Recherche Diversité et Adaptation des Plantes (UMR DAP) Université Dan Dicko Dankoulodo de Maradi Maradi Niger institut de Recherche pour le Développement UMR Espace-DEV Université de Perpignan Via Domitia (UPVD) Perpignan France institut de Recherche pour le Développement Représentation Niamey Niger Centre imaan de Support en Recherche Transdisciplinaire UMR DAP/UDDM Niamey Niger Département des Sciences et Techniques de Productions Végétales Université Dan Dicko Dankoulodo de Maradi UMR DAP Maradi Niger

Spatio-temporal variability and dynamics in Sahelian agro-pastoral zones make each local situation a special case. These specificities must be considered to guide the dissemination of agricultural options with a view to sustainable development. The territorial scale of municipalities is not sufficient for this necessary contextualization;the scale of the “village terroir” seems to be a better option. This is the hypothesis we put forward in the framework of the Global Collaboration for Resilient Food Systems program (CRFS), i.e. local context is spatially defined by village terroir. The study is based on data collected through participatory mapping and surveys in “village terroirs” in three regions of Niger (Maradi, Dosso and Tillabéri). Then the links between farm managers and their cultivated land, as well as the spatio-temporal dynamics of local context are analyzed. This study provides evidence of the existence and functional usefulness of the village terroir for farmers, their land management and their activities. it demonstrates the usefulness of contextualizing agricultural options at this scale. Their analysis elucidates the links between “terroirs village” and the specific functioning of the agrosocio-ecosystems acting on each of them, thus laying the systemic and geographical foundations for a model of the spatio- temporal dynamics of “village terroirs”. This initial work has opened up new perspectives in modeling and sustainable development.

关键词： Niger Option by Context Local Condition Complex System Multiscale Conceptual Modeling

Cable-Driven Parallel Robot Workspace identification and Optimal Design Based on the Upper Limb Functional Rehabilitation

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Journal of Bionic Engineering 2022年第2期19卷 390-402页

作者： Ferdaws Ennaiem Abdelbadia Chaker Juan Sandoval sami Bennour Abdelfattah Mlika Lotfi Romdhane said Zeghloul Med Amine Laribi Department of GMSC Pprime Institute CNRSENSMAUniversity of PoitiersUPR 3346PoitiersFrance Mechanical Laboratory of Sousse(LMS) National Engineering School of SousseUniversity of Sousse4000 SousseTunisia American University of Sharjah PO Box 26666SharjahUnited Arab Emirates

An assessment of the human motion repeatability for three selected Activities of Daily Living(ADL)is performed in this *** exercises were prescribed by an occupational therapist for the upper limb *** movement patterns of five participants,recorded using a Qualisys motion capture system,are compared based on the Analysis of Variance(ANOVA)*** survey is motivated by the need to find the appropriate task workspace of a 6-degrees of freedom cable-driven parallel robot for upper limb rehabilitation,which is able to reproduce the three selected *** comparison is performed to justify,whether or not,there is enough similarity between the participants’gestures,and so a single reference trajectory can be adopted as the robot-prescribed *** the results of the comparative study,an optimization process of the sought robot design is carried out,where the structure size and the cable tensions simultaneously minimized.

关键词： Human motion repeatability Activities of Daily Living(ADL) Analysis of Variance(ANOVA) Task workspace Cable-driven parallel robot Upper limb rehabilitation Optimization