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Flow and natural convection heat transfer characteristics of non-Newtonian nanofluid flow bounded by two infinite vertical flat plates in presence of magnetic field and thermal radiation using Galerkin method

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Journal of Central South University 2019年第5期26卷 1294-1305页

作者： Peyman MAGHSOUDI Gholamreza SHAHRIARI Hamed RASAM sadegh sadeghi School of Engineering University of TehranTehran ***Iran School of Engineering Iran University of Science and TechnologyTehran ***Iran

The main goal of this paper is to investigate natural convective heat transfer and flow characteristics of non-Newtonian nanofluid streaming between two infinite vertical flat plates in the presence of magnetic field and thermal ***,a similarity transformation is used to convert momentum and energy conservation equations in partial differential forms into non-linear ordinary differential equations (ODE) applying meaningful boundary *** order to obtain the non-linear ODEs analytically,Galerkin method (GM) is ***,the ODEs are also solved by a reliable numerical *** order to test the accuracy,precision and reliability of the analytical method,results of the analytical analysis are compared with the numerical *** respect to the comparisons,fairly good compatibilities with insignificant errors are ***,the impacts of effective parameters including magnetic and radiation parameters and nanofluid volume fraction on the velocity,skin friction coefficient and Nusselt number distributions are comprehensively *** on the results,it is revealed that with increasing the role of magnetic force,velocity profile,skin friction coefficient and thermal performance *** parameter has insignificant influence on velocity profile while it obviously has augmentative and decreasing effects on skin friction and Nusselt number,respectively.

关键词： non-Newtonian flow nanofluid flow Galerkin method magnetic field radiation

Molecular detection of Anaplasma marginale and Anaplasma ovis in sheep and goat in west highland pasture of Iran

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Asian Pacific Journal of Tropical Biomedicine 2017年第5期7卷 455-459页

作者： Ali Yousefi sadegh Rahbari Parviz Shayan Zainab sadeghi-dehkordi Alireza Bahonar Department of Microbiology Science and Research BranchIslamic Azad University Department of Parasitology Faculty of Veterinary MedicineUniversity of Tehran Department of Parasitology Faculty of Paraveterinary MedicineBu-Ali Sina University Department of Food Hygiene and Quality Control Faculty of Veterinary MedicineUniversity of Tehran

Objective:To determine the prevalence of Anaplasma marginale(***) and Anaplasma ovis from sheep and goat in different highland pasture in west of ***:From July 2015 to October 2015,370 blood samples of sheep and goat were collected from different regions in Hamedan province,*** DNA extracted from blood and subsequently,16 S r RNA and MSP4 genes were analyzed by nested-PCR,semi nested-PCR and RFLP ***:In the PCR assessment,overall 27.5%(102/370) of sheep and goat were positive for Anaplasma ovis and *** infection,which was lower than reports from tropical and subtropical regions of *** analysis(the Chi-square test) did not show any significant relation between infection and variables such as location,tick infestation age and sex(P > 0.05).No significant correlation between the altitude and the Anaplasma species infection was found(Mann–Whitney test:P > 0.05).However,Anaplasma infection in goat significantly is more than the sheep(P = 0.008).Conclusions:The ecological changes affect the frequency and distribution of Anaplasma ***,our results indicate that sheep as potential reservoirs of ***.

关键词： Anaplasma PCR Sheep Goat Iran

Ranking of design scenarios of TMD for seismically excited structures using TOPSIS

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Frontiers of Structural and Civil Engineering 2020年第6期14卷 1372-1386页

作者： sadegh ETEDALI Department of Civil Engineering Birjand University of TechnologyBirjand 97175-569Iran

In this paper,desigh scenarios of a tuned mass damper(TMD)for seismically excited structures are ***,10 design scenarios in two cases,namely unconstrained and constrained for the maximum TMD,are considered in this study.A free search of the TMD parameters is performed using a particle swarm optimization(PSO)algorithm for optimum tuning of TMD ***,nine criteria are adopted with respect to functional,operational,and economic views.A technique for order performance by similarity to ideal solution(TOPSIS)is utilized for ranking the adopted design scenarios of *** studies are conducted on a 10-story building equipped with *** results indicate that the minimization of the maximum story displacement is the optimum design scenario of TMD for the seismic-excited structure in the unconstrained case for the maximum TMD ***,H2 of the displacement vector of the structure exhibited optimum ranking among the adopted design scenarios in the constrained case for the maximum TMD *** findings of this study can be useful and important in the optimum design of TMD parameters with respect to functional,operational,and economic perspectives.

关键词： seismic-excited building TMD optimum design PSO design scenario TOPSIS

Production of ultra-transparent glass-ceramics via controlled crystallization of nanocrystals in the glassy matrix of LAST

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International Journal of Minerals,Metallurgy and Materials 2014年第1期21卷 71-76页

作者： Mohammad sadegh Shakeri Materials and Energy Research Center(MERC)

Microstructural variation in glass-ceramics encompasses the range from nanocrystalline transparent materials to microcrystalline tough materials. In this investigation, the crystallization process was controlled for the development of ultra transparent LiEO-A1203-SiO2 glass-ceramics containing TiO2 as a nucleating agent （LAST）. Results of UV-Vis absorption spectra were compared with the expected theo- retical values calculated by the Rayleigh scattering method for the determination of ultra transparency. Results of the investigation illustrate that the control of crystallization increases the range of ultra transparency by the reduction of crystal size and their uniformity in the glassy matrix. Last but not the least, the optimized samples are ultra transparent approximately in the whole light wavelengths.

关键词： glass-ceramics transparency nanocrystals crystallization

Fabrication,microstructure,and optical properties of nanocrystalline transparent LAST glass ceramics containing CeO_2

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International Journal of Minerals,Metallurgy and Materials 2014年第4期21卷 401-407页

作者： Mohammad sadegh Shakeri Materials and Energy Research Center (MERC)

In the present research, the effect of CeO2 dopant on the fabrication of transparent lithium aluminosilicate titanate （LAST） glass ceramics was investigated. Nanocrystallineβ-quartz solid solution （s.s.） was observed to be the main phase crystallized in this system. Com-parable refractive indices of the glassy matrix andβ-quartz s.s., as well as the incorporation of very fine grains size were determined as the main reasons for retaining the transparency of the glass ceramics. CeO2 was introduced as a suitable optical agent, playing a role as a network modifier in the glass ceramics, because it does not accelerate the growth process and retards the extended growth of crystals. Optical investi-gations indicate that the Fermi energy level, direct and indirect band gaps, and Urbach energy decrease with increasing nanocrystal content in the glassy matrix of specimens, which can be related to the expansion of conduction band, the enhancement of ionic bonds in the crystal lat-tice, and the enhancement of structural arrangement degree, respectively.

关键词： glass ceramics nanocrystals alurninosilicates titanates transparency optical properties

Effect of Y_2O_3 on the crystallization kinetics of TiO_2 nucleated LAS glass for the production of nanocrystalline transparent glass ceramics

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International Journal of Minerals,Metallurgy and Materials 2013年第5期20卷 450-455页

作者： Mohammad sadegh Shakeri Materials and Energy Research Center (MERC) P.O. Box 31779-83634KarajIran

Crystallization kinetics of metastable B-quartz solid solution as a desirable phase for the production of trans- parent lithium aluminosilicate （LAS） glass ceramics was investigated in the presence of Y203. Accordingly, differential thermal analysis scans were performed thoroughly to study the mechanism of crystallization kinetics. The aim of this investigation is to discover the complicated mechanism of crystallization process in the presence of co-additives and ac- cordingly find a way for increasing the transparency of glass ceramics. It is shown that the bulk （3D） growth is intensively increased by the enhancement of Y203. Then again, reducing nucleation and increasing growth mechanisms were recog- nized for the LAS system in the presence of Y2O3. Results of the investigation illustrate that when co-additives are added to glasses, it is necessary to nucleate the optical component separately before the growth process.

关键词： glass ceramics lithium aluminosilicate yttria crystallization kinetics nanocrystals transparency

Analysis of Spray Evaporation in a Model Evaporating Chamber:Effect of Air Swirl

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Journal of Thermal Science 2023年第2期32卷 837-853页

作者： Mohammad sadegh ABEDINEJAD Department of Mechanical Engineering Faculty of EngineeringAlzahra UniversityTehranIran

Spray evaporation of liquid fuels in a turbulent flow is a common process in various engineering applications such as *** between fuel droplets(discrete phase)and fluid flow(continuous phase)have a considerable effect on liquid fuel *** this paper,both the single-and two-phase modeling of liquid fuel injection into a model evaporating chamber are *** influences of important issues such as turbulence models,coupling between gas phase and droplets,secondary break-up and air swirling on the current spray simulation are ***,the shear stress transport turbulence model,Taylor analogy break-up and two-way coupling models are applied to simulate the two-phase *** and spray of fuel droplets in hot air are modeled employing an Eulerian-Lagrangian *** current results show an acceptable agreement with the *** the fuel atomizer,bigger droplets are detected near the spray edge and minor droplets are situated in the *** increasing the droplets axial position,the droplets diameter decreases with a finite *** smaller droplets have a deeper penetration,but their lifetime is smaller and they evaporate sooner.A linear relation between penetration and lifetime of smaller droplets is *** droplet penetration and mean axial velocity of gas phase are observed for no air swirling *** effect of variation of swirl number on the lifetime of droplets is almost *** enhancing the swirl number,the uniformity of droplet size distribution is reduced and some large droplets are formed up in the domain.

关键词： secondary break-up droplet evaporation air swirling fuel spray gas-droplets coupling

ON THE STABILITY OF FUSION FRAMES (FRAMES OF SUBSPACES)

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Acta Mathematica Scientia 2011年第4期31卷 1633-1642页

作者： Mohammad sadegh Asgari Department of Mathematics Faculty of Science Islamic Azad University Central Tehran Branch Central Tehran Branch

A frame is an orthonormal basis-like collection of vectors in a Hilbert space, but need not be a basis or orthonormal. A fusion frame （frame of subspaces） is a frame-like collection of subspaces in a Hilbert space, thereby constructing a frame for the whole space by joining sequences of frames for subspaces. Moreover the notion of fusion frames provide a framework for applications and providing efficient and robust information processing *** this paper we study the conditions under which removing an element from a fusion frame, again we obtain another fusion frame. We give another proof of [5, Corollary 3.3（iii）] with extra information about the bounds.

关键词： fusion frames (frames of subspaces) exact fusion frame dual fusion frames

Nonlinear finite time attitude control of flexible spacecraft based on a novel output redefinition method

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Chinese Journal of Aeronautics 2023年第11期36卷 373-385页

作者： Seyed Majid ESMAEILZADEH Mohammad sadegh ZEYGHAMI Department of Electrical Engineering Iran University of Science and TechnologyNarmakTehran 16846-13114Iran

A finite time attitude controller is designed for a flexible spacecraft based on a novel output redefinition method, in this paper. To make the flexible appendages vibration suppression effective, the appendage tip-point is selected as the output. First, a novel output redefinition method is proposed to overcome the non-minimum phase property of the dynamic model. The proposed method not only makes the system model minimum phase but also improves the attitude control system performance. Consequently, the precise attitude pointing and stabilization are ***, a nonlinear finite time H∞controller is designed based on the backstepping approach. For the situation where the modal variables measurements are not available, a modal observer is also designed. The simulation results show the effectiveness of the proposed method in the presence of the model uncertainties and environmental disturbances.

关键词： Finite time Output redefinition H1 control Attitude control Flexible spacecraft Backstepping Robust