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modal interactions in primary and subharmonic resonant dynamics of imperfect microplates with geometric nonlinearities

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Acta mechanica Sinica 2016年第3期32卷 469-480页

作者： hamed Farokhi mergen h.Ghayesh Department of mechanical Engineering McGill University School of mechanical Materials and MechatronicEngineering University of Wollongong

This paper analyses the modal interactions in the nonlinear, size-dependent dynamics of geometrically imperfect microplates. Based on the modified couple stress theory,the equations of motion for the in-plane and out-of-plane motions are obtained employing the von Kármán plate theory as well as Kirchhoff＇s hypotheses by means of the Lagrange equations. The equations of motions are solved using the pseudo-arclength continuation technique and direct timeintegration method. The system parameters are tuned to the values associated with modal interactions, and then nonlinear resonant responses and energy transfer are *** motion characteristics are shown in the form of frequency-response and force-response curves, time histories, phase-plane portraits, and fast Fourier transforms.

关键词： modal interactions microplate Sizedependent dynamics modified couple stress theory Stability

heat transfer analysis in the flow of Walters' B fluid with a convective boundary condition

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Chinese Physics B 2014年第8期23卷 382-388页

作者： T.hayat Sadia Asad m.mustafa hamed h.Alsulami Department of mathematics Quaid-i-Azam University 45320 Department of mathematics Faculty of Science King Abdulaziz University School of Natural Sciences National University of Science and Technology (NUST)

Radiative heat transfer in the steady two-dimensional flow of Walters＇ B fluid with a non-uniform heat source/sink is investigated. An incompressible fluid is bounded by a stretching porous surface. The convective boundary condition is used for the thermal boundary layer problem. The relevant equations are first simplified under usual boundary layer assumptions and then transformed into a similar form by suitable transformations. Explicit series solutions of velocity and temperature are derived by the homotopy analysis method （hAm）. The dimensionless velocity and temperature gradients at the wall are calculated and discussed.

关键词： Walters' B fluid heat source/sink convective boundary condition analytic solution

Ant Colony Optimization for multi-Objective multicast Routing

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Computers, materials & Continua 2020年第6期63卷 1159-1173页

作者： Ahmed Y.hamed monagi h.Alkinani m.R.hassan Department of Computer Science Faculty of Computers and InformationSohag UniversitySohag82524Egypt Department of Computer Science and Artificial Intelligence College of Computer Science and EngineeringUniversity of JeddahJeddah21959Saudi Arabia Department of mathematics and Computer Science Faculty of ScienceAswan UniversityAswan81528Egypt

In the distributed networks,many applications send information from a source node to multiple destination *** support these applications requirements,the paper presents a multi-objective algorithm based on ant colonies to construct a multicast tree for data transmission in a computer *** proposed algorithm simultaneously optimizes total weight(cost,delay and hop)of the multicast *** results prove the proposed algorithm outperforms a recently published multi-objective multicast Algorithm specially designed for solving the multicast routing ***,it is able to find a better solution with fast convergence speed and high reliability.

关键词： multimedia communication multicast routing multicast tree quality of service ant colony

A Genetic Algorithm to Solve Capacity Assignment Problem in a Flow Network

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Computers, materials & Continua 2020年第9期64卷 1579-1586页

Computer networks and power transmission networks are treated as capacitated flow networks.A capacitated flow network may partially fail due to ***,the capacity of each edge should be optimally assigned to face critical situations-i.e.,to keep the network functioning normally in the case of failure at one or more *** robust design problem(RDP)in a capacitated flow network is to search for the minimum capacity assignment of each edge such that the network still survived even under the edge’s *** RDP is known as ***,capacity assignment problem subject to system reliability and total capacity constraints is studied in this *** problem is formulated mathematically,and a genetic algorithm is proposed to determine the optimal *** optimal solution found by the proposed algorithm is characterized by maximum reliability and minimum total *** numerical examples are presented to illustrate the efficiency of the proposed approach.

关键词： Flow network capacity assignment network reliability genetic algorithms

Grasshopper KUWAhARA and Gradient Boosting Tree for Optimal Features Classifications

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Computers, materials & Continua 2022年第8期72卷 3985-3997页

作者： Rabab hamed m.Aly Aziza I.hussein Kamel h.Rahouma The higher Institute for management and Information Technology Minya61768Egypt Department of Electrical and Computer Engineering Effat UniversityJeddahKSA Electrical Engineering Department Faculty of EngineeringMinia UniversityMinia6111Egypt

This paper aims to design an optimizer followed by a Kawahara filter for optimal classification and prediction of employees’*** algorithm starts by processing data by a modified K-means technique as a hierarchical clustering method to quickly obtain the best features of employees to reach their best *** work of this paper consists of two *** first part is based on collecting data of employees to calculate and illustrate the performance of each *** second part is based on the classification and prediction techniques of the employee *** model is designed to help companies in their decisions about the employees’*** classification and prediction algorithms use the Gradient Boosting Tree classifier to classify and predict the *** of the paper give the percentage of employees which are expected to leave the company after predicting their performance for the coming *** also show that the Grasshopper Optimization,followed by“KF”with the Gradient Boosting Tree as classifier and predictor,is characterized by a high *** proposed algorithm is compared with other known techniques where our results are fund to be superior.

关键词： metaheuristic algorithm KUWAhARA filter Grasshopper optimization algorithm and Gradient boosting tree

Nanofillers modification of Epocast 50-A1/946 epoxy for bonded joints

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Chinese Journal of Aeronautics 2014年第5期27卷 1288-1300页

作者： U.A.Khashaba A.A.Aljinaidi m.A.hamed Department of mechanical Engineering Faculty of Engineering King Abdulaziz University

Epocast 50-A1/946 epoxy was primarily developed for joining and repairing of composite aircraft structural components. The objective of the present work is to modify the Epocast epoxy resin by different nanofillers infusion. The used nanofillers include multi-walled carbon nanotubes（mWCNTs）, SiC and Al2O3 nanoparticles. The nanofillers with different weight percentages are ultrasonically dispersed in the epoxy resin. The sonication time and amplitude for mWCNTs are reduced compared to Al2O3 and SiC nanoparticles to avoid the damage of mWCNTs during sonication processes. The fabricated neat epoxy and twelve nanocomposite panels were characterized via standard tension and in-plane shear tests. The experimental results show that the nanocomposites materials with 0.5wt% mWCNTs, 1.5wt% SiC and 1.5wt% Al2O3 nanoparticles have the highest improvement in the tensile properties compared to the other nanofiller loading *** improvements in the shear properties of these nanocomposite materials were respectively equal to 5.5%, 4.9%, and 6.3% for shear strengths, and 10.3%, 16.0%, and 8.1% for shear moduli. The optimum nanofiller loading percentages will be used in the following papers concerning their effect on the bonded joints/repairs of carbon fiber reinforced composites.

关键词： Iosipescu shear tests Nanocomposites Optimum nanofiller weight percentage Scanning electron microscopic Tension tests Ultrasonic

Task Scheduling Optimization in Cloud Computing Based on Genetic Algorithms

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Computers, materials & Continua 2021年第12期69卷 3289-3301页

作者： Ahmed Y.hamed monagi h.Alkinani Faculty of Computers and Information Department of Computer ScienceSohag UniversitySohag82524Egypt Department of Computer Science and Artificial Intelligence College of Computer Science and EngineeringUniversity of JeddahJeddah21959Saudi Arabia

Task scheduling is the main problem in cloud computing that reduces system performance;it is an important way to arrange user needs and perform multiple *** computing is the most popular technology nowadays and has many research potential in various areas like resource allocation,task scheduling,security,privacy,*** improve system performance,an efficient task-scheduling algorithm is *** task-scheduling algorithms focus on task-resource requirements,CPU memory,execution time,and execution *** this paper,a task scheduling algorithm based on a Genetic Algorithm(GA)has been presented for assigning and executing different *** proposed algorithm aims to minimize both the completion time and execution cost of tasks and maximize resource *** evaluate our algorithm’s performance by applying it to two examples with a different number of tasks and *** first example contains ten tasks and four processors;the computation costs are generated *** last example has eight processors,and the number of tasks ranges from twenty to seventy;the computation cost of each task on different processors is generated *** achieved results show that the proposed approach significantly succeeded in finding the optimal solutions for the three objectives;completion time,execution cost,and resource utilization.

关键词： Cloud computing task scheduling genetic algorithm optimization algorithm

Antimicrobial properties of dental cements modified with zein-coated magnesium oxide nanoparticles

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Bioactive materials 2022年第2期7卷 49-56页

作者： Ghada h.Naguib hani m.Nassar mohamed T.hamed Department of Restorative Dentistry Faculty of DentistryKing Abdulaziz UniversityJeddahSaudi Arabia Department of Oral Biology Faculty of DentistryCairo UniversityCairoEgypt Department of Oral and maxillofacial Prosthodontics King Abdulaziz UniversityFaculty of DentistryJeddahSaudi Arabia Department of Fixed Prosthodontics Faculty of DentistryCairo UniversityCairoEgypt

The aim of this study was to test the antimicrobial properties of dental cements modified with magnesium oxide(mgO)***-modified mgO nanoparticles(zmgO)in concentrations(0.0,0.3,0.5,and 1.0%)were mixed with dental cements(Fuji II,Rely X Temp E,Ionoglass Cem,Es Temp NE,and System P link).Eight discs were fabricated from each zmgO-cement pair for a total of 32 specimens for each *** of the dental cements incorporating zmgO was done by X-ray Diffraction(XRD)and Field Emission Scanning Electron microscopy(FESEm).The antimicrobial properties of the mixtures were tested using direct contact and agar diffusion assays against Streptococcus mutans,Staphylococcus aureus,Enterococcus faecalis,and Candida *** was analyzed using two-way analysis of variance and LSD post hoc test at 0.05 significance *** spectra showed sharp peaks of zmgO indicating its high crystalline nature,while the amorphous dental cements with zmgO had broad *** analysis showed a uniform distribution of the zmgO nanoparticles in the *** were significant inhibition zone values associated with all concentrations of zmgO-cement mixtures tested compared to controls(ph a dose-response recorded only with Fuji *** density values were significantly lower in zmgO groups compared to controls for all *** effect was most prominent with Rely X against *** and *** cements containing zmgO showed significant antimicrobial properties that were dependent on the specific initial cement substrate.

关键词： magnesium oxide nanoparticles Antimicrobial biomaterials Dental cement Nanocoatings

Experimental and mathematical modeling of Cr(Ⅵ) removal using nano-magnetic Fe3O4-coated perlite from the liquid phase

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Chinese Journal of Chemical Engineering 2020年第6期28卷 1582-1590页

作者： Ismail m.Ahmed mostafa m.hamed Sayed S.metwally Chemistry Department College of ScienceJouf UniversitySkakaSaudi Arabia hot Laboratories and Waste management Center Atomic Energy Authority13759 CairoEgypt

modification of perlite using nano-magnetic iron oxide was implemented to produce nano-magneticFe3O4-coated perlite composite(Fe3O4/Perlite).The prepared composite was characterized using Scanning Electron microscopy,Fourier-Transform Infrared spectroscopy and Powder X-ray *** potentiality of both perlite and Fe3O4/Perlite composite to eliminate Cr(VI)from the environmentally relevant water was *** influence of main factors which could affect the adsorption was studied including;ph of medium,shaking time and Cr(VI)ions *** experimental outcome demonstrated that the modification of perlite by nano-magnetic Fe3O4 showed a significantly enhanced Cr(VI)removal efficiency relative to that of unmodified *** the kinetic studies,the experimental data fitted well with the pseudo-second-order ***,it proposes that Langmuir isotherm is more adequate than the Freundlich isotherm for both perlite and modified *** results recommended that Fe3O4/Perlite composite had a great potential as an economic and efficient adsorbent of Cr(VI)from contaminated water,which has huge application potential.

关键词： Nano-magnetic Composite Kinetics Isotherm Perlite Adsorption