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Seismic analysis of semi-sine shaped alluvial hills above subsurface circular cavity

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Earthquake Engineering and Engineering Vibration 2020年第4期19卷 903-917页

作者： Mehdi Panji mohammad Habibivand Department of Civil Engineering Zanjan BranchIslamic Azad UniversityZanjanIran

In this study, a seismic analysis of semi-sine shaped alluvial hills above a circular underground cavity subjected to propagating oblique SH-waves using the half-plane time domain boundary element method(BEM) was carried out. By dividing the problem into a pitted half-plane and an upper closed domain as an alluvial hill and applying continuity/boundary conditions at the interface, coupled equations were constructed and ultimately, the problem was solved step-by-step in the time domain to obtain the boundary values. After solving some verification examples, a semi-sine shaped alluvial hill located on an underground circular cavity was successfully analyzed to determine the amplification ratio of the hill surface. For sensitivity analysis, the effects of the impedance factor and shape ratio of the hill were also considered. The ground surface responses are illustrated as three-dimensional graphs in the time and frequency domains. The results show that the material properties of the hill and their heterogeneity with the underlying half-space had a significant effect on the surface response.

关键词： alluvial semi-sine shaped hill half-plane BEM time domain circular cavity SH waves

Mechanical properties and microstructural evolution of rheocast A356 semi-solid slurry prepared by annular electromagnetic stirring

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China Foundry 2023年第4期20卷 315-328页

作者： mohammad Taghi Asadi Khanouki Department of Materials and Metallurgy Engineering Shahid Bahonar University of KermanP.O.Box ***KermanIran Mineral Industries Research Center(MIRC) Shahid Bahonar University of KermanP.O.Box ***KermanIran

Nowadays,having an effective technique in preparing semi-solid slurries for rheocasting process seems to be an essential *** this study,semi-solid slurry of A356 aluminum alloy was prepared by three-phase annular electromagnetic stirring(A-EMS)technique under different *** effects of stirring current,pouring temperature and stirring time on microstructural evolution,mean particle size,shape factor and solid fraction were *** rheocasting process was carried out by using a drop weight setup and to inject the prepared semi-solid slurry in optimal conditions into the step-die *** filling behavior and mechanical properties of parts were *** evolution showed that the best semi-solid slurry which had fine spherical particles with the average size of~27μm and a shape factor of~0.8 was achieved at the stirring current of 70 A,melt pouring temperature of 670℃,and stirring time of 30 *** these conditions,the step-die cavity was completely filled at die preheating temperature of 470℃.The hardness increases by decreasing step thickness as well as die preheating ***,the tensile properties are improved at lower die preheating *** fracture surface,which consists of a complex topography,indicates a typical ductile fracture.

关键词： semi-solid slurry annular electromagnetic stirring rheocast A356 aluminum alloy microstructural evolution mechanical properties magnetic flux density

Slender reinforced concrete shear walls with high-strength concrete boundary elements

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Frontiers of Structural and Civil Engineering 2023年第1期17卷 138-151页

作者： mohammad SYED Pinar OKUMUS Department of Civil Structural and Environmental EngineeringUniversity at BuffaloBuffaloNY 14260USA

Reinforced concrete structural walls are commonly used for resisting lateral forces in buildings. Owing to the advancements in the field of concrete materials over the past few decades, concrete mixes of high compressive strength, commonly referred to as high-strength concrete (HSC), have been developed. In this study, the effects of strategic placement of HSC on the performance of slender walls were examined. The finite-element model of a conventional normal-strength concrete (NSC) prototype wall was validated using test data available in extant studies. HSC was incorporated in the boundary elements of the wall to compare its performance with that of the conventional wall at different axial loads. Potential reductions in the reinforcement area and size of the boundary elements were investigated. The HSC wall exhibited improved strength and stiffness, and thereby, allowed reduction in the longitudinal reinforcement area and size of the boundary elements for the same strength of the conventional wall. Cold joints resulting from dissimilar concrete pours in the web and boundary elements of the HSC wall were modeled and their impact on behavior of the wall was examined.

关键词： slender walls high-strength concrete rectangular and barbell-shaped walls cold joints

MILP Optimization Model for Assessing the Participation of Distributed Residential PV-battery Systems in Ancillary Services Market

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CSEE Journal of Power and Energy Systems 2021年第2期7卷 348-357页

作者： Pierluigi Siano Dolatabadi mohammad Department of Management&Innovation Systems Via Giovanni Paolo II132Fisciano(Salerno)84084Italy Department of Mathematics Vali-e-Asr University of RafsanjanKerman ProvinceRafsanjanUnnamed RoadRafsanjan ***Iran

A novel non-linear stochastic method based on a Mixed-Integer Linear Programming(MILP)optimization model is proposed to optimally manage a high number of photovoltaic(PV)-battery systems for the provision of up and down regulation in the ancillary services *** method,considers both the technical constraints of the power system,and those of the equipment used by all the *** allows an aggregator of many residential prosumers endowed with photovoltaic(PV)-battery systems to evaluate the baseline of the aggregate by minimizing the costs related to the electrical energy absorbed from the grid and then to assess the up and down flexibility curves with relative offer *** confirmed by simulation results carried out considering different realistic case studies,the method can effectively be used by an aggregator to evaluate the economic impact of its participation in the ancillary services market,both for the aggregator and for its prosumers.

关键词： Aggregator ancillary services market mixed-integer linear programming optimization PV-battery systems up and down regulation

On Solvability of Groups with a Few Non-cyclic Subgroups

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Algebra Colloquium 2016年第1期23卷 105-110页

作者： mohammad Zarrin Department of Mathematics University of Kurdistan P.O. Box 416 Sanandaj Iran

Li and Zhao studied groups with a few conjugacy classes of non-cyclic subgroups. In this paper we study groups with a few non-cyclic subgroups. In fact, among other things, we give some sufficient conditions on the nu... 详细信息

关键词： solvable group simple group

On Behavior of Solutions to a Class of Nonlinear Hyperbolic Inverse Source Problem

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Acta Mathematica Sinica,English Series 2016年第6期32卷 683-698页

作者： mohammad SHAHROUZI Department of Mathematics Jahrom University

This article is concerned with a class of hyperbolic inverse source problem with memory term and nonlinear boundary damping. Under appropriate assumptions on the initial data and pa- rameters in the equation, we establish two results on behavior of solutions. At first we proved stability of solutions when the integral overdetermination tends to zero as time goes to infinity and finally a blow-up result is established for certain solution with positive initial energy.

关键词： Inverse problem asymptotic stability blow up memory boundary feedback

Hybrid Modified Chimp Optimization Algorithm and Reinforcement Learning for Global Numeric Optimization

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Journal of Bionic Engineering 2023年第6期20卷 2896-2915页

作者： mohammad ShDaoud mohammad Shehab Laith Abualigah Cuong-Le Thanh College of Engineering Al Ain University112612 Abu DhabiUnited Arab Emirates College of Computer Sciences and Informatics Amman Arab UniversityAmman 11953Jordan Center for Engineering Application Technology Solutions Ho Chi Minh City Open UniversityHo Chi Minh City 700000Vietnam

Chimp Optimization Algorithm(ChOA)is one of the most efficient recent optimization algorithms,which proved its ability to deal with different problems in various ***,ChOA suffers from the weakness of the local search technique which leads to a loss of diversity,getting stuck in a local minimum,and procuring premature *** response to these defects,this paper proposes an improved ChOA algorithm based on using Opposition-based learning(OBL)to enhance the choice of better solutions,written as ***,utilizing Reinforcement Learning(RL)to improve the local research technique of OChOA,called *** way effectively avoids the algorithm falling into local *** performance of the proposed RLOChOA algorithm is evaluated using the Friedman rank test on a set of CEC 2015 and CEC 2017 benchmark functions problems and a set of CEC 2011 real-world *** results and statistical experiments show that RLOChOA provides better solution quality,convergence accuracy and stability compared with other state-of-the-art algorithms.

关键词： Chimp optimization algorithm Reinforcement learning Disruption operator Opposition-based learning CEC 2011 real-world problems CEC 2015 and CEC 2017 benchmark functions problems

Robust PID controller design for time delay processes with peak of maximum sensitivity criteria

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Journal of Central South University 2014年第10期21卷 3777-3786页

作者： mohammad Shamsuzzoha Department of Chemical Engineering King Fahd University of Petroleum and Minerals

The motivation of this work is to obtain single PI/PID tuning formula for different types of processes with enhanced disturbance rejection performance. The proposed tuning formula consistently gives better performance in comparison to several well-known methods at the same degree of robustness for stable, integrating and unstable processes. For the selection of the closed-loop time constant(τc), a guideline is provided over a broad range of time-delay/time-constant ratios on the basis of the peak of maximum sensitivity(Ms). An analysis has been performed for the uncertainty margin with the different process parameters for the robust controller design. It gives the guideline of the Ms-value settings for the PI controller designs based on the process parameters uncertainty. Furthermore, a relationship has been developed between Ms-value and uncertainty margin with the different process parameters(k, τ and θ). Simulation study has been conducted for the broad class of processes and the controllers are tuned to have the same degree of robustness by measuring the maximum sensitivity, Ms, in order to obtain a reasonable comparison.

关键词： PI/PID controller tuning internal model control(IMC) method unstable delay process integrating delay process disturbance rejection

Application of coupled XFEM-BCQO in the structural optimization of a circular tunnel lining subjected to a ground motion

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Frontiers of Structural and Civil Engineering 2019年第6期13卷 1495-1509页

作者： Nazim Abdul NARIMAN Ayad mohammad RAMADAN Ilham Ibrahim mohammad Department of Civil Engineering Tishk International University-SulaimaniSulaimaniya 46001Iraq Mathematics Department-College of Science Sulaimani UniversitySulaimaniya 46001Iraq

A new structural optimization method of coupled extended finite element method and bound constrained quadratic optimization method(XFEM-BCQO)is adopted to quantify the optimum values of four design parameters for a circular tunnel lining when it is subjected to *** parameters are:tunnel lining thickness,tunnel diameter,tunnel lining concrete modulus of elasticity and tunnel lining concrete ***-Carlo sampling method is dedicated to construct the meta models so that to be used for the BCQO method using matlab *** simulations of the tensile damage in the tunnel lining due to a real earthquake in the literature are created for three design *** approach is used to show the cracks for the mentioned design *** results of the BCQO method for the maximum design case for the tunnel tensile damage was matching the results obtained from XFEM approach to a fair *** new coupled approach manifested a significant capability to predict the cracks and spalling of the tunnel lining concrete under the effects of dynamic earthquakes.

关键词： ovaling deformation monte carlo sampling XFEM-BCQO maximum principal stress