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A new artificial bee swarm algorithm for optimization of proton exchange membrane fuel cell model parameters

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第8期12卷 638-646页

作者： Alireza ASKARZADEH Alireza rezazadeh Faculty of Electrical and Computer Engineering Shahid Beheshti University

An appropriate mathematical model can help researchers to simulate,evaluate,and control a proton exchange membrane fuel cell (PEMFC) stack *** a PEMFC is a nonlinear and strongly coupled system,many assumptions and approximations are considered during ***,some differences are found between model results and the real performance of *** increase the precision of the models so that they can describe better the actual performance,opti-mization of PEMFC model parameters is *** this paper,an artificial bee swarm optimization algorithm,called ABSO,is proposed for optimizing the parameters of a steady-state PEMFC stack model suitable for electrical engineering *** studying the usefulness of the proposed algorithm,ABSO-based results are compared with the results from a genetic algo-rithm (GA) and particle swarm optimization (PSO).The results show that the ABSO algorithm outperforms the other algorithms.

关键词： Proton exchange membrane fuel cell stack model Parameter optimization Artificial bee swarm optimization algorithm

Studying thin film damping in a micro-beam resonator based on non-classical theories

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Acta Mechanica Sinica 2016年第3期32卷 369-379页

作者： Mina Ghanbari Siamak Hossainpour Ghader rezazadeh Mechanical Engineering Department Sahand University of Technology Mechanical Engineering Department Faculty of Engineering Urmia University

In this paper, a mathematical model is presented for studying thin film damping of the surrounding fluid in an in-plane oscillating micro-beam resonator. The proposed model for this study is made up of a clamped-clamped micro-beam bound between two fixed layers. The microgap between the micro-beam and fixed layers is filled with air. As classical theories are not properly capable of predicting the size dependence behaviors of the micro-beam,and also behavior of micro-scale fluid media, hence in the presented model, equation of motion governing longitudinal displacement of the micro-beam has been extracted based on non-local elasticity theory. Furthermore, the fluid field has been modeled based on micro-polar theory. These coupled equations have been simplified using Newton-Laplace and continuity equations. After transforming to non-dimensional form and linearizing, the equations have been discretized and solved simultaneously using a Galerkin-based reduced order model. Considering slip boundary conditions and applying a complex frequency approach, the equivalent damping ratio and quality factor of the micro-beam resonator have been obtained. The obtained values for the quality factor have been compared to those based on classical theories. We have shown that applying non-classical theories underestimate the values of the quality factor obtained based on classical theo-ries. The effects of geometrical parameters of the micro-beam and micro-scale fluid field on the quality factor of the resonator have also been investigated.

关键词： Thin film damping micro-electromechanical systems(MEMS) Micro-polar theory

Optimization of total harmonic current distortion and torque pulsation reduction in high-power induction motors using genetic algorithms

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第12期9卷 1741-1752页

作者： Arash SAYYAH Mitra AFLAKI Alireza rezazadeh Department of Electrical and Computer Engineering University of Illinois at Urbana-ChampaignUrbanaIL 61801USA Graduate School of Management and Economics Sharif University of TechnologyTehranIran Department of Electrical and Computer Engineering Shahid Beheshti UniversityTehranIran

This paper presents a powerful application of genetic algorithm （GA） for the minimization of the total harmonic current distortion （THCD） in high-power induction motors fed by voltage source inverters, based on an approximate harmonic model. That is, having defined a desired fundamental output voltage, optimal pulse patterns （switching angles） are determined to produce the fundamental output voltage while minimizing the THCD. The complete results for the two cases of three and five switching instants in the first quarter period of pulse width modulation （PWM） waveform are presented. Presence of harmonics in the stator excitation leads to a pulsing-torque component. Considering the fact that if the pulsing-torques are at low frequencies, they can cause troublesome speed fluctuations, shaft fatigue, and unsatisfactory performance in the feedback control system, the 5th, 7th, 1 lth, and 13th current harmonics （in the case of five switching angles） are constrained at some pre-specified values, to mitigate the detrimental effects of low-frequency harmonics. At the same time, the THCD is optimized while the required fundamental output voltage is maintained.

关键词： Induction motor Genetic algorithm (GA) Optimization Pulse width modulation (PWM) Torque pulsation Totalharmonic current distortion (THCD)

A computational study of a capsule lateral migration in microchannel flow

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Acta Mechanica Sinica 2013年第4期29卷 513-525页

作者： M.Navidbakhsh M.rezazadeh Department of Mechanical Engineering Iran University of Science and Technology

A numerical method is used to model a capsule migration in a microchannel with small Reynolds number Re = 0.01. The capsule is modeled as a liquid drop sur- rounded by a neo-Hookean elastic membrane. The numer- ical model combines immersed boundary with lattice Boltz- mann method （IB-LBM）. The LBM is used to simulate fixed Cartesian grid while the IBM is utilized to implement the fluid-structure interaction by a set of Lagrangian moving grids for the membrane. The effect of shear elasticity and bending stiffness are both considered. The results show the significance of elastic modulus and initial lateral position on deformation and morphological properties of a circular cap- sule. The wall effect becomes stronger as the capsule ini- tial position gets closer to the channel wall. As the elastic modulus of membrane increases, the capsule undergoes less pronounced deformation and velocity in direction x is de- creased, thus, the capsule motion is slower than the back- ground flow. The best agreement between the present model and experiments for migration velocity takes place for the capsule with normal to moderate membrane elastic modulus. The results are in good agreement with experiment study of Coupier et al. and previous numerical studies. Therefore, the IB-LBM can be employed to make prediction in vitro and in vivo studies of capsule deformation.

关键词： Capsule. Lateral migration. Lattice Boltzmann.Immersed boundary ~ Deformation ~ Initial position

Empirical methods for determining shaft bearing capacity of semi-deep foundations socketed in rocks

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第6期9卷 1140-1151页

作者： S.rezazadeh A.Eslami Department of Civil and Environmental Engineering Amirkabir University of TechnologyTehranIran

Semi-deep foundations socketed in rocks are considered to be a viable option for the foundations in the presence of heavy load imposed by high-rise structures, due to the low settlement and high bearing capacity. In the optimum design of semi-deep foundations, prediction of the shaft bearing capacity, rs, of foundations socketed in rocks is thus critically important. In this study, the unconfined compressive strength(UCS), qu, has been applied in order to investigate the shaft bearing capacity. For this, a database of 106 full-scale load tests is compiled with UCS values of surrounding rocks, in which 34 tests with rock quality designation(RQD), and 5 tests with rock mass rating(RMR). The bearing rocks for semi-deep foundations include limestone, mudstone, siltstone, shale, granite, tuff, granodiorite, claystone, sandstone, phyllite, schist, and greywacke. Using the database, the applicability and accuracy of the existing empirical methods are evaluated and new relations are derived between the shaft bearing capacity and UCS based on the types of rocks. Moreover, a general equation in case of unknown rock types is proposed and it is verified by another set of data. Since rock-socketed shafts are supported by rock mass(not intact rock), a reduction factor for the compressive strength is suggested and verified in which the effect of discontinuities is considered using the modified UCS, qu(modified), based upon RMR and RQD in order to take into account the effect of the rock mass properties.

关键词： Shaft bearing capacity Semi-deep foundations Database Rock-socketed shaft Unconfined compressive strength(UCS)

Active Control of A Piston-Type Absorbing Wavemaker with Fully Reflective Structure

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China Ocean Engineering 2020年第5期34卷 730-737页

作者： Saeed MAHJOURI Rasoul SHABANI Ghader rezazadeh Peyman BADIEI Department of Mechanical Engineering Faculty of EngineeringUrmia UniversityUrmiaIran South Ural state University ChelyabinskRussian Federation cDepartment of Civil Engineering Tehran UniversityTehranIran

Multiple reflections of the waves between structure and wavemaker in hydraulic flumes could change the frequency content of the desired incident wave or result in resonance. A prominent approach to avoid multiple reflections is active control of the wavemaker. This paper proposes a simple and practical active control algorithm for piston-type wavemaker. The block diagram of the control system is presented in real time domain. It is shown that there is no need to use any transfer function or filter in the feedback and feed forward loops and the use of constant gains can yield acceptable results. In the operating frequency range(0.25-2 Hz), it is revealed that the proposed system is very effective at suppressing the excitation of resonant sloshing for regular wave. In the case of irregular waves, it is depicted that the experimental waves agree quite well with the desired wave elevation in frequency domain. In addition, comparison of the results obtained both with and without absorption discloses the good characteristics in time domain.

关键词： wave flume piston-type wavemaker active absorption mathematical modeling reflective waves

STABILITY ANALYSIS OF A CAPACITIVE FGM MICRO-BEAM USING MODIFIED COUPLE STRESS THEORY

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Acta Mechanica Solida Sinica 2013年第4期26卷 427-440页

作者： Behrokh Abbasnejad Ghader rezazadeh Rasool Shabani Mechanical Engineering Department Urmia University

Based on the Modified Couple Stress Theory,a functionally graded micro-beam under electrostatic forces is *** FGM micro-beam is made of two materials and material properties vary continuously along the beam thickness according to a *** and static pull-in voltages are obtained and it is shown that the static and dynamic pull-in voltages for some materials cannot be obtained using classic theories and components of couple stress must be taken into *** addition,it is shown that the values of pull-in voltages depend on the variation through the thickness of the volume fractions of the two constituents.

关键词： MEMS FGM micro-beam stability pull-in voltage electrostatic pressure modified couple stress theory

Effect of inertia nonlinearity on dynamic response of an asymmetric building equipped with tuned mass dampers

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Earthquake Engineering and Engineering Vibration 2020年第2期19卷 499-513页

作者： Hassan rezazadeh Fereidoun Amini Majid Amin Afshar School of Civil Engineering Iran University of Science and TechnologyP.O.Box 16765-163TehranIran Department of Technology and Engineering Imam Khomeini International University NorouzianP.O.Box 34149-16818QazvinIran

This study investigates the effect of nonlinear inertia on the dynamic response of an asymmetric building equipped with Tuned Mass Dampers(TMDs).In the field of structural engineering,many researchers have developed models to study the behavior of nonlinear TMDs,but the effect of nonlinear inertia has not received as much attention for asymmetric *** consider nonlinear inertia,the equations of motion are derived in a local rotary coordinates *** displacements and rotations of the modeled building and TMDs are defined by five-degree-of-freedom(5-DOFs).The equations of motion are derived by using the Lagrangian *** in the proposed nonlinear model,the equations of motion are different from a conventional linear *** order to compare the response of the proposed nonlinear model and a conventional linear model,numerical examples are presented and the response of the modeled buildings are derived under harmonic and earthquake *** is shown that if the nonlinear inertia is considered,the response of the modeled structures changes and the conventional linear approach cannot adequately model the dynamic behavior of the asymmetric buildings which are equipped with TMDs.

关键词： Nonlinear inertia tuned mass damper asymmetric buildings harmonic excitation seismic excitation

Coordination of PSS and TCSC controller using modified particle swarm optimization algorithm to improve power system dynamic performance

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Journal of Zhejiang University-Science C(Computers and Electronics) 2010年第8期11卷 645-653页

作者： Alireza rezazadeh Mostafa SEDIGHIZADEH Ahmad HASANINIA Faculty of Electrical and Computer Engineering Shahid Beheshti University Faculty of Engineering and Technology Imam Khomeini International University

This paper develops a modified optimization procedure for coordination of a power system stabilizer (PSS) and a thyristor controlled series compensator (TCSC) controller to enhance the power system small signal *** new approach employs eigenvalue-based and time-domain simulation based objective functions simultaneously to improve the optimization convergence rate.A modified particle swarm optimization (MPSO) algorithm is used as the optimization *** results of simulations and eigenvalue analysis for a single machine infinite bus (SMIB) system equipped with the proposed PSS and TCSC controllers confirm that the new approach is effective in enhancing the system stability.

关键词： Coordination Particle swarm optimization (PSO) Power system stabilizer (PSS) Small signal stability Thyristor controlled series compensator (TCSC) controller