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Thermal Buckling Analysis of Size-Dependent FG Nanobeams Based on the Third-Order Shear Deformation Beam Theory

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Acta Mechanica Solida Sinica 2016年第5期29卷 547-554页

作者： Farzad ebrahimi mohammad reza Barati Department of Mechanical Engineering Faculty of EngineeringImam Khomeini International University

In this paper,the thermal effects on the buckling of functionally graded（FG） nanobeams subjected to various types of thermal loading including uniform,linear and non-linear temperature changes are investigated based on the nonlocal third-order shear deformation beam *** material properties of FG nanobeam are supposed to vary gradually along the thickness direction according to the power-law *** governing equations are derived through Hamilton＇s principle and solved *** examples are performed to verify the present *** results are presented for thermal buckling analysis of FG nanobeams such as the effects of the power-law index,nonlocal parameter,slenderness ratio and thermal loading in detail.

关键词： buckling functionally governing verify graded exponent supposed Shear analytically elasticity

Temperature distribution effects on buckling behavior of smart heterogeneous nanosize plates based on nonlocal four-variable refined plate theory

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International Journal of Smart and Nano Materials 2016年第3期7卷 119-143页

作者： Farzad ebrahimi mohammad reza Barati Department of Mechanical Engineering Faculty of EngineeringImam Khomeini International UniversityQazvinIran

This work presents a theoretical study for thermo-mechanical buckling of size-dependent magneto-electro-thermo-elastic func-tionally graded(METE-FG)nanoplates in thermal environments based on a refined trigonometric plate *** field has uniform,linear,and nonlinear distributions across the *** thermal loadings are considered as heat conduc-tion(HC)and sinusoidal temperature rise(STR).A power law function is applied to govern the gradation of material properties through the nanoplate *** coupling impacts between magneto,electro,thermo-mechanical loadings,the equa-tions of motion,and distribution of magneto-electrical field across the thickness direction of the METE-FG nanoplate are *** exact solutions for critical buckling temperatures of METE-FG nanoplates are introduced implementing Navier’s ***,the accuracy of the present formulation is examined by comparing the obtained results with published ***,the effects played by the magneto-electrical field,various temperature rises,nonlocality,power law index,side-to-thickness ratio,and aspect ratio on the critical buckling tempera-ture response are all investigated and reported.

关键词： METE-FG nanoplate thermal buckling four-variable refined plate theory nonlocal elasticity

Electromechanical buckling behavior of smart piezoelectrically actuated higher-order size-dependent graded nanoscale beams in thermal environment

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International Journal of Smart and Nano Materials 2016年第2期7卷 69-90页

作者： Farzad ebrahimi mohammad reza Barati Department of Mechanical Engineering Faculty of EngineeringImam Khomeini International UniversityQazvinI.R.Iran

In the present work,thermo-electro-mechanical buckling behavior of functionally graded piezoelectric(FGP)nanobeams is investi-gated based on higher-order shear deformation beam *** FGP nanobeam is subjected to four types of thermal loading including uniform,linear,and sinusoidal temperature rise as well as heat conduction through the beam ***-electro-mechanical properties of FGP nanobeam are supposed to change continuously in the thickness direction based on power-law *** consider the influences of small-scale sizes,Eringen’s nonlocal elasticity theory is *** Hamilton’s princi-ple,the nonlocal governing equations of an FGP nanobeam in thermal environments are obtained and are solved using Navier-type analytical *** significance of various parameters,such as thermal loadings,external electric voltage,power-law index,nonlocal parameter,and slenderness ratio on thermal buck-ling response of size-dependent FGP nanobeams is investigated.

关键词： Functionally graded piezoelectric nanobeam thermal buckling nonlocal elasticity theory higher-order beam theory

Molybdenite alkali fusion and leaching:reactions and mechanism

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International Journal of Minerals,Metallurgy and Materials 2010年第2期17卷 127-131页

作者： reza ebrahimi-Kahrizsangi mohammad Hasan Abbasi Ali Saidi Department of Materials Engineering Islamic Azad University Department of Materials Engineering Isfahan University of Technology

The production of MoO3 from Sarcheshmeh molybdenite concentrate via a pyro-hydrometallurgical process was *** molybdenite concentrate and sodium carbonate were premixed and fused under air *** the fused products were leached in water and the dissolved molybdenum was recovered as ammonium *** ammonium molybdate was then calcined to produce mo-lybdic *** the fusion stage,the effect of the mass ratio of carbonate to sulfide on the reaction products and the solubility of the products was *** results show that during the fusion,sodium molybdate and sodium sulfate are the final reaction products and sodium sulfide is detected as an intermediate reaction *** melting at 850℃with 5wt%excess carbonate,the maximum solubility of the products is *** molybdenum is recovered from the solutions as ammonium molybdate.

关键词： molybdenite alkali fusion leaching sodium molybdate molybdic oxide

Mechanical Properties of Al/BN Nanocomposites Fabricated by Planetary Ball Milling and Conventional Hot Extrusion

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Acta Metallurgica Sinica(English Letters) 2018年第3期31卷 245-253页

作者： reza Gostariani Ramin ebrahimi Mohsen Asadi Asadabad mohammad Hossein Paydar Department of Materials Science and Engineering School of Engineering Shiraz University Materials and Nuclear Fuel Research School Nuclear Science and Technology Research InstituteTehran Iran

In this study,Al matrix nanocomposites containing 1,2 and 4 wt% nano-boron nitride were fabricated by mechanical milling and hot *** mechanical properties of all extruded samples were ***,the morphology and microstructure of the milled composite powders were characterized using two types of electron *** results showed that a high fraction of the boron nitride nanoparticles dissolved and formed a solid solution in Al matrix during the milling *** the process of solid solution formation,the work hardening rate of the composite powders *** led to a morphological change in the composite powders and resulted in equiaxed *** powder particle size also decreased after the milling *** increasing boron nitride content within a range of 0--4 wt% in the hot extruded samples,tensile stress increased from 212 to 333 *** hardness of the nanocomposite samples including 1,2 and 4 wt% boron nitride improved approximately 55,70 and 90% in comparison with pure Al,respectively.

关键词： Al/BN nanocomposite Planetary ball milling Hot extrusion Mechanical properties Microstructure

A fuzzy logic model to predict the out-of-seam dilution in longwall mining

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International Journal of Mining Science and Technology 2015年第1期25卷 91-98页

作者： Ali Bahri Najafi mohammad Ali ebrahimi Farsangi Golam reza Saeedi Mining Engineering Department Shahid Bahonar University of Kerman

The longwall mining method is often affected by the out-of-seam dilution （OSD）. Therefore, predicting and controlling of dilution are important factors for reducing mining costs. In this study, the fuzzy set theory and multiple regression models with parameters, including variation in seam thickness, dip of seam, seam thickness, depth of seam, and hydraulic radius as inputs to the models were applied to pre- dict the OSD in the longwall coal panels. Field data obtained from Kerman and Tabas coal mines, lran were used to develop and validate the models. Three indices including coefficient of determination （R2）, root mean square error （RMSE） and variance account for （VAF） were used to evaluate the perfor- mance of the models. With 10 randomly selected datasets, for the linear, polynomial, power, exponential, and fuzzy logic models, R2, RSME and VAF are equal to （0.85, 4.4, 84.4）, （0.61, 7.5, 59.6）, （0.84, 4.5, 72.7）, （0.80, 4.1, 79.6）, and （0.97, 2.1, 95.7）, respectively. The obtained results indicate that the fuzzy logic model predictor with R2 = 0.97, RMSE = 2.1, and VAF = 95.7 performs better than the other models.

关键词： Out-of-seam dilutionLongwall coal miningRegression modelingFuzzy set theoryKerman and Tabas coal mines

Operational indicators for measuring organizational e-readiness based on fuzzy logic: A challenge in the Agricultural Organization of Guilan Province, Iran

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Information Processing in Agriculture 2014年第2期1卷 115-123页

作者： Zahra Daghighi Masouleh mohammad Sadegh Allahyari reza ebrahimi Atani Young Researchers and Elite Club Rasht BranchIslamic Azad UniversityRashtIran Department of Agricultural Management Rasht BranchIslamic Azad UniversityRashtIran Department of Computer Engineering University of GuilanRashtIran

Information and communications technology has exponentially grown in recent years and has played a significant role in organizational *** main purpose of this study was to collect the data needed for the introduction of a new tool for assessing e-readiness in the Agricultural Organization of Guilan Province,*** study population includes agricultural organization experts and researchers who were familiar with the concepts of IT and the organization *** on the relevant literature review,the e-readiness indicators which had theoretically been proposed and practically used by researchers over the past 10 years were *** some parameters were introduced for examination and *** indicators represented the spatial and temporal factors as well as the characteristics of the condition of the Agricultural Organization of Guilan *** proposed structural model included seven factors(Infrastructural,Human,Educational,Government,Management,Socio-cultural and Legal)and 44 *** that,based on the experts’points of view,the coefficient of significance for each of the selected factors and indicators was measured using Minkowski fuzzy screening *** results obtained from structured questionnaires show that all of the seven main factors and 40 indicators out of 44 indicators were appropriate for assessing electronic readiness and the final model of assessing ***,the results indicated that the most important factor in assessing e-readiness is the human factor and then stand other factors such as educational,infrastructural,management,government,legal and socio-cultural.

关键词： Electronic readiness Expert group Information and communications technology Iran Minkowski fuzzy screening method

Stabilizing silica nanoparticles in high saline water by using polyvinylpyrrolidone for reduction of asphaltene precipitation damage under dynamic condition

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Chinese Journal of Chemical Engineering 2019年第5期27卷 1021-1029页

作者： mohammad reza Aghajanzadeh mohammad Sharifi Department of Petroleum Engineering Amirkabir University of Technology

In this study, the performance of stable nanofluid containing SiO2 nanoparticles dispersed and stabilized in high salinity brine for asphaltene inhibition in dynamic condition is evaluated. In the first stage of this work, the stability of silica nanoparticles in different range of water salinity(0–100000 mg·L-1) is investigated. Next, stable nanofluid containing highest salinity is selected as asphaltene inhibitor agent to inject into the damaged core sample. The estimated values of oil recovery for base case, after damage process and after inhibition of asphaltene precipitation using nanofluid are 51.6%, 36.1% and 46.7%, respectively. The results showed the reduction in core damage after using nanofluid. In addition, the relative permeability curves are plotted for the base case, after damage process and also after inhibition of asphaltene precipitation using nanofluid. Comparison of relative permeability curves shows, relative permeability of oil phase decreased after damage process as compared with the base case. But after using nanofluid the oil relative permeability curve has shifted to the right and effective permeability of oil phase has been improved.

关键词： Formation damage Enhanced oil recovery Salinity Asphaltene Core flooding Nano particles

Finite element analysis of stress and strain distributions in mortise and loose tenon furniture joints

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Journal of Forestry Research 2014年第3期25卷 677-681页

作者： mohammad Derikvand Ghanbar ebrahimi Department of Wood and Paper Science and Technology College of Agriculture and Natural Resources University of Tehran

We studied the effect of loose tenon dimensions on stress and strain distributions in T-shaped mortise and loose tenon （M＆amp;LT） furni-ture joints under uniaxial bending loads, and determined the effects of loose tenon length （30, 45, 60, and 90 mm） and loose tenon thickness （6 and 8 mm） on bending moment capacity of M＆amp;LT joints constructed with polyvinyl acetate （PVAc） adhesive. Stress and strain distributions in joint elements were then estimated for each joint using ANSYS finite element （FE） software. The bending moment capacity of joints increased significantly with thickness and length of the tenon. Based on the FE analysis results, under uniaxial bending, the highest shear stress values were obtained in the middle parts of the tenon, while the highest shear elastic strain values were estimated in glue lines between the tenon sur-faces and walls of the mortise. Shear stress and shear elastic strain values in joint elements generally increased with tenon dimensions and corre-sponding bending moment capacities. There was consistency between predicted maximum shear stress values and failure modes of the joints.

关键词： bending moment capacity, failure mode, finite element,furniture, mortise and loose tenon joint stress and strain distributions