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Communications in Theoretical Physics 2018年第6期69卷 637-644页

作者： K.ParAND m.Nikarya Department of Computer Sciences Shahid Beheshti University

The Klein-Cordon equation arises in many scientific areas of quantum mechanics and quantum field theory. In this paper a novel method based on spectral method and Jacobian free Newton method composed by generalized minimum residual （JFNGmRes） method with adaptive preconditioner will be introduced to solve nonlinear Klein-Gordon equation. In this work the nonlinear Klein-Gordon equation has been converted to a nonlinear system of algebraic equations using collocation method based on Bessel functions without any linearization, discretization and getting help of any other methods. Finally, by using JFNGmRes, solution of the nonlinear algebraic system will be achieved. To illustrate the reliability and efficiency of the proposed method, we solve some examples of the Klein-Gordon equation and compare our results with other methods.

关键词： nonlinear partial differential equation spectral collocation methods Jacobian free Newton-GmRes adaptive preconditioning Klein-Gordon equations nonlinear algebraic systems

Solubility prediction of disperse dyes in supercritical carbon dioxide and ethanol as co-solvent using neural network

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Chinese Journal of Chemical Engineering 2016年第4期24卷 491-498页

作者： Ahmad KhazaiePoul m. Soleimani S. Salahi Faculty of Water and Environmental Engineering Shahid Beheshti University Tehran Iran Amol University of Special modern Technologies Amo146168-49767 Iran Chemical Engineering Department Islamic Azad University Shahrood Branch Shahrood Iran

Nowadays artificial neural networkS （ANNs） with strong ability have been applied widely for prediction of non- linear phenomenon. In this work an optimized ANN with 7 inputs that consist of temperature, pressure, critical temperature, critical pressure, density, molecular weight and acentric factor has been used for solubility predic- tion of three disperse dyes in supercritical carbon dioxide （SC-C02） and ethanol as co-solvent. It was shown how a multi-layer perceptron network can be trained to represent the solubility of disperse dyes in SC-C02. Numeric Sensitivity Analysis and Garson equation were utilized to find out the degree of effectiveness of different input variables on the efficiency of the proposed model. Results showed that our proposed ANN model has correlation coefficient, Nash-Sutcliffe model efficiency coefficient and discrepancy ratio about 0.998, 0.992, and 1.053 respectively.

关键词： SolubilityDisperse dyesSupercritical carbon dioxideNeural networksCo-solvent

Velocity gradient elasticity for nonlinear vibration of carbon nanotube resonators

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Frontiers of Structural and Civil Engineering 2020年第6期14卷 1520-1530页

作者： hamid mSEDIGHI Hassen mOUAKad mechanical Engineering Deparment Faculty of Engineering Shahid Chamran University of AhvazAhvaz ***Iran Driling Center of Exellence and Research Center Shahid Chamran University of AhvazAhvaz ***Iran mechanical and Industrial Engineering Department Collge of EngineeringSultan Qaboos UniversitMuscalOMAN

In this study,for the first time,we investigate the nonlocality superimposed to the size effects on the nonlinear dynamics of an electrically actuated single-walled carbon-nanotube-based *** undertake two models to capture the nanostructure nonlocal size effects:the strain and the velocity gradient *** use a reduced-order model based on the differential quadrature method(DQm)to discretize the goverming nonlinear equation of motion and acquire a discretized-parameter nonlinear model of the *** structural nonlinear behavior of the system assuming both strain and velocity gradient theories is investigated using the discretized *** results suggest that nonlocal and size effects should not be neglected because they improve the prediction of corresponding dynamic amplitudes and,most importantly,the critical resonant frequencies of such *** these effects may impose a considerable source of error,which can be amended using more accurate modeling techniques.

关键词： velocity gradient elasticity theory nanotube resonators differential-quadrature method nonlinear vibration

DYNAmIC PULL-IN INSTABILITY OF DOUBLE-SIDED ACTUATED NANO-TORSIONAL SWITCHES

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Acta mechanica Solida Sinica 2015年第1期28卷 91-101页

作者： hamid m.Sedighi Kourosh H.Shirazi Department of mechanical Engineering Shahid Chamran University

A nonlinear frequency-amplitude relation is developed to investigate the vibrational amplitude effect on the dynamic pull-in instability of double-sided-actuated nano-torsional switches. The governing equation of a nano-electro-mechanical system pre-deformed by an electric field contains the quintic nonlinear term. The influences of basic parameters on the pull-in instability and natural frequency are investigated using a powerful analytical approach called the homotopy perturbation method. It is demonstrated that two terms in series expansion are sufficient to produce an acceptable solution. The numerical results obtained have verified the soundness of the asymptotic procedure. The phase portraits of the double-sided nano-torsionalactuator exhibit periodic, homoclinic and heteroclinic orbits.

关键词： homotopy perturbation method frequency-amplitude relationship double-sidedactuated nano-switch dynamic pull-in instability homoclinic orbit heteroclinic orbit

Theoretical and experimental investigation of gas metal arc weld pool in commercially pure aluminum:Effect of welding current on geometry

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Journal of Central South University 2017年第11期24卷 2556-2564页

作者： Farzadi A morakabiyan Esfahani m Alavi Zaree S R Department of mining and metallurgical Engineering Amirkabir University of Technology Department of materials Science and Engineering Faculty of EngineeringShahid Chamran University of Ahvaz

Effects of welding current on temperature and velocity fields during gas metal arc welding(GmAW) of commercially pure aluminum were simulated. Equations of conservation of mass, energy and momentum were solved in a three-dimensional transient model using FLOW-3 D software. The mathematical model considered buoyancy and surface tension driving forces. Further, effects of droplet heat content and impact force on weld pool surface deformation were added to the model. The results of simulation showed that an increase in the welding current could increase peak temperature and the maximum velocity in the weld pool. The weld pool dimensions and width of the heat-affected zone(HAZ) were enlarged by increasing the welding current. In addition, dimensionless Peclet, Grashof and surface tension Reynolds numbers were calculated to understand the importance of heat transfer by convection and the roles of various driving forces in the weld pool. In order to validate the model, welding experiments were conducted under several welding currents. The predicted weld pool dimensions were compared with the corresponding experimental results, and good agreement between simulation and preliminary test results was achieved.

关键词： simulation modeling heat transfer fluid flow AA1100 aluminum alloy finite element method (FEm) weld pool geometry temperature and velocity fields

Integral treatment for forced convection heat and mass transfer of nanofluids over linear stretching sheet

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Applied mathematics and mechanics(English Edition) 2015年第3期36卷 337-352页

作者： A.NOGHREHABadI P.SALAmAT m.GHALAmBAZ Department of mechanical Engineering Shahid Chamran University of Ahvaz

An integral treatment is proposed for the analysis of the forced convection flow of a nanofluid over a stretching sheet. The obtained results agree well with the numerical results. The results of the presented solution provide an analytic solution, which can be conveniently used in engineering applications. Four types of nanoparticles, i.e., alumina （Al2O3）, silicon dioxide （Si02）, silver （Ag）, and copper （Cu）, dispersed in the base fluid of water are examined. The analytical results show that an increase in the volume fraction of nanoparticles increases the thickness of the thermal boundary layer. The reduced Nusselt number is a decreasing function of the volume fraction of nanoparticles. ＇ Key words nanofluid, integral method, stretching sheet, analytical solution, thermal enhancement

关键词： nanofluid integral method stretching sheet analytical solution thermal enhancement

Nucleon/nuclei polarized structure function,using Jacobi polynomials expansion

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Chinese Physics C 2010年第9期34卷 1534-1537页

作者： A.mirjalili m.m.Yazdanpanah F.Taghavi-Shahri S.Atashbar Tehrani Physics Department Yazd University School of Particles and Accelerators Institute for Research in Fundamental Sciences (IPM) Physics Department Kerman Shahid Bahonar University

We use the constituent quark model to extract polarized parton distributions and finally polarized nucleon structure *** to limited experimental data which do not cover whole （x,Q 2 ） plane and to increase the reliability of the fitting,we employ the Jacobi orthogonal polynomials *** will be possible to extract the polarized structure functions for Helium,using the convolution of the nucleon polarized structure functions with the light cone moment *** results are in good agreement with available experimental data and some theoretical models.

关键词： perturbative QCD nucleon and nuclei structure function jacobi polynomials

A laboratory study of hot WAG injection into fractured and conventional sand packs

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Petroleum Science 2009年第4期6卷 400-404页

作者： m J Dorostkar A mohebbi A Sarrafi A Soltani Department of Chemical Engineering College of EngineeringShahid Bahonar University of Kerman

Gas injection is the second largest enhanced oil recovery process, next only to the thermal method used in heavy oil fields. To increase the extent of the reservoir contacted by the injected gas, the gas is generally injected intermittently with water. This mode of injection is called water-alternating-gas (WAG). This study deals with a new immiscible water alternating gas (IWAG) EOR technique, “hot IWAG” which includes combination of thermal, solvent and sweep techniques. In the proposed method CO2 will be superheated above the reservoir temperature and instead of normal temperature water, hot water will be used. Hot CO2 and hot water will be alternatively injected into the sand packs. A laboratory test was conducted on the fractured and conventional sand packs. Slugs of water and CO2 with a low and constant rate were injected into the sand packs alternatively; slug size was 0.05 PV. Recovery from each sand pack was monitored and after that hot water and hot CO2 were injected alternatively under the same conditions and increased oil recovery from each sand pack and breakthrough were measured. Experimental results showed that the injection of hot WAG could significantly recover residual oil after WAG injection in conventional and fractured sand packs.

关键词： Hot water-alternating-gas (WAG) enhanced oil recovery (EOR) fractured sand pack conventional sand pack gas injection

Natural convection of nanofluid over vertical plate embedded in porous medium: prescribed surface heat flux

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Applied mathematics and mechanics(English Edition) 2013年第6期34卷 669-686页

作者： A. NOGHREHABadI A. BEHSERESHT m. GHALAmBAZ Department of mechanical Engineering Shahid Chamran University of Ahvaz

The aim of the present paper is to analyze the natural convection heat and mass transfer of nanofluids over a vertical plate embedded in a saturated Darcy porous medium subjected to surface heat and nanoparticle fluxes. To carry out the numerical solution, two steps are performed. The governing partial differential equations are firstly simplified into a set of highly coupled nonlinear ordinary differential equations by appropriate similarity variables, and then numerically solved by the finite difference method. The obtained similarity solution depends on four non-dimensional parameters, i.e., the Brownian motion parameter （Nb）, the buoyancy ratio （Nr）, the thermophoresis parameter （Nt）, and the Lewis number （Le）. The variations of the reduced Nusselt number and the reduced Sherwood number with Nb and Nt for various values of Le and Nr are discussed in detail. Simulation results depict that the increase in Nb, Nt, or Nr decreases the reduced Nusselt number. An increase in the Lewis number increases both of the reduced Nusselt number and the Sherwood number. The results also reveal that the nanoparticle concentration boundary layer thickness is much thinner than those of the thermal and hydrodynamic boundary layers.

关键词： natural convection porous medium nanofluid surface heat flux surfacenanoparticle flux

Application of a finite element method to stress distribution in buried patch repaired polyethylene gas pipes

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Underground Space 2019年第1期4卷 48-58页

作者： R.Khademi-Zahedi m.Shishesaz shahid Chamran University of Ahvaz AhvazIran

advantages of polyethylene pipes over traditional steel or metal pipes have increased industry interest in the use of polyethylene(PE)pipelines for underground applications and especially in gas distribution *** this study,finite element analysis is used to calculate the stress distribution in a patch repaired defective gas pipe under internal *** pipe is assumed to be buried at a depth of 125 *** material is assumed to be medium density PE80B,where the patch material was selected from high density polyethylene(HDPE).During the loading process,the seasonal pipe temperature changes,surcharge loads,soil column weight,and soil-pipe interaction were included in the *** types of patch arrangements were selected to repair the damaged *** shape of the defect hole was deemed as circular or *** respect to elliptic defects,various minor to major diameter ratios,a/b,were selected to simulate a circular to a crack shaped *** on the results,the semi-circular and saddle fusion patches decrease the peak von mises stress in the pipe by almost the same ***,the minimum peak von mises stress in the patch corresponds to the saddle fusion repair *** on the results,with respect to a saddle fusion repair,when the shape of the defect approaches a crack,the peak von mises stress in the pipe almost doubles and exceeds the pipe allowable stress for a working life of 50 *** respect to higher values of a/b,the stress level in the patch repaired pipe is significantly below its limiting value for the same life expectancy.

关键词： Patch repair Buried gas pipe mDPE HDPE Temperature variation