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Numerical and experimental study of an innovative pipeline design in a granular pneumatic-conveying system

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Particuology 2018年第3期16卷 196-203页

作者： Hasan Ghafori Hamid reza ebrahimi Department of Mechanical Engineering MaJlesi Branch Islamic Azad University lsfilhan Iran Department of Chemical Engineering Majlesi Branch Islamic Azad University lsfahan Iran

During gas-solid mixture conveying in a dense phase, material is conveyed in dunes on the bottom of the pipeline, or as a pulsating moving bed. This phenomenon increases the pressure drop and power consumption. We introduce a new technique to reduce the pressure drop, which is termed the perforated double tube. To validate this new model, the gas-solid flow pattern and pressure drop were studied numerically and experimentally. The power consumption was also studied experimentally. Numerical studies were performed by the Eulerian-Lagrangian approach to predict gas and particle movement in the pipeline, Comparisons between the numerical predictions and the experimental results for the gas-solid flow patterns and pressure drop show good agreement.

关键词： Computational fluid dynamics Power consumption Perforated double tube Pneumatic conveying

NUMERICAL SIMULATION OF SPHERICAL, CYLINDRICAL AND AXIAL BUBBLE CLOUDS COLLAPSE

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Journal of Hydrodynamics 2012年第4期24卷 569-578页

作者： MAHDI Miralam ebrahimi reza SHAMS Mehrzad Faculty of Mechanical Engineering K.N.Toosi University of Technology Tehran Iran

The nonlinear dynamics of a spherical, cylindrical and axial cloud of cavitation bubbles were numerically simulated in order to learn more about the physical phenomena occurring in the cloud cavitation. The simulations employed the fully nonlinear continuum mixture equations coupled with the Gilmore equation for the dynamics of bubbles by considering the compressibility of liquid. A set of the Navier-Stokes equations was solved for the gas inside a spherical bubble, considering heat transfer through the gas inside the bubble and the liquid layer. The flow field around the cylindrical and axial cloud was obtained by solving the Navier-Stokes equations using a finite volume method and a dynamic layering mesh scheme. The calculated strength of shock wave in the liquid around the cloud was of the order of 1 ×10^6 Pa and the propagation of this shock wave lasted for l0 p.s. The conducted investigations illustrate that the shock wave propagates before the cloud has completely collapsed. A good agreement with experimental data was observed.

关键词： cloud cavitation shock wave spherical cloud cylindrical cloud axial cloud

Lattice parameters of Ti–4Al–2V alloy with thermal oxidation

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Rare Metals 2016年第2期35卷 149-153页

作者： Faraz Omidbakhsh Ali reza ebrahimi Department of Mechanical Engineering Tabriz Branch Islamic Azad University Mining and Metallurgical Engineering Department Amirkabir University of Technology

In this study, the effect of thermal oxidation on the lattice parameters of Ti-4Al-2V alloy was *** were oxidized at 450, 600 and 650 °C for 1-7 h in electric furnace under air atmosphere. The lattice parameters were determined using the Cohen method as a function of oxidation time at each temperature. The lattice parameters of as-received alloy are calculated as a = 0.29289 nm and c = 0.46652 nm. The thermal oxidation at 450 °C results in a gradual increase in a-parameter, whereas it goes through a maximum at higher temperatures（600 and 700 °C）. The results show that these maximums are reduced to an approximately constant value after a long-time oxidation. The c-parameter generally increases over the whole treatment condition. It is believed that these variations could be due to the dissolution of oxygen atoms in octahedral sites of hcp lattice of titanium.

关键词： Lattice parameter Ti-4Al-2V X-ray diffraction Cohen method Octahedral sites

The Bedbug Meta-heuristic Algorithm to Solve Optimization Problems

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Journal of Bionic Engineering 2023年第5期20卷 2465-2485页

作者： Kouroush Rezvani Ali Gaffari Mohammad reza ebrahimi Dishabi Department of Computer Engineering Miyaneh BranchIslamic Azad UniversityMiyanehIran Department of Computer Engineering Tabriz BranchIslamic Azad UniversityTabrizIran

Small parasitic Hemipteran insects known as bedbugs(Cimicidae)feed on warm-blooded mammal’s *** most famous member of this family is the Cimex lectularius or common *** current paper proposes a novel swarm intelligence optimization algorithm called the Bedbug Meta-Heuristic Algorithm(BMHA).The primary inspiration for the bedbug algorithm comes from the static and dynamic swarming behaviors of bedbugs in *** two main stages of optimization algorithms,exploration,and exploitation,are designed by modeling bedbug social interaction to search for *** proposed algorithm is benchmarked qualitatively and quantitatively using many test functions including *** results of evaluating BMHA prove that this algorithm can improve the initial random population for a given optimization problem to converge towards global optimization and provide highly competitive results compared to other well-known optimization *** results also prove the new algorithm's performance in solving real optimization problems in unknown search *** achieve this,the proposed algorithm has been used to select the features of fake news in a semi-supervised manner,the results of which show the good performance of the proposed algorithm in solving problems.

关键词： Bedbug Meta-Heuristic Algorithm Optimization algorithm BMHA

U-shaped energy loss curves utilization for distributed generation optimization in distribution networks

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Journal of Zhejiang University-Science C(Computers and Electronics) 2013年第11期14卷 887-898页

作者： reza ebrahimi Mehdi EHSAN Hassan NOURI Department of Electrical Engineering Science and Research BranchIslamic Azad University Centre of Excellence in Power System Management and Control (CEPSMC) Sharif University of Technology Department of Engineering Design and Mathematics University of the West of England (UWE Bristol)

We propose novel techniques to find the optimal location,size,and power factor of distributed generation(DG) to achieve the maximum loss reduction for distribution *** the optimal DG location and size is achieved simultaneously using the energy loss curves technique for a pre-selected power factor that gives the best DG *** on the network's total load demand,four DG sizes are *** are used to form energy loss curves for each bus and then for determining the optimal DG *** study shows that by defining the energy loss minimization as the objective function,the time-varying load demand significantly affects the sizing of DG resources in distribution networks,whereas consideration of power loss as the objective function leads to inconsistent interpretation of loss reduction and other *** devised technique was tested on two test distribution systems of varying size and complexity and validated by comparison with the exhaustive iterative method(EIM) and recently published *** showed that the proposed technique can provide an optimal solution with less computation.

关键词： Distributed generation(DG) Distribution networks Loss reduction DG optimization Energy loss curves

Hot compression deformation behavior of AISI 321 austenitic stainless steel

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International Journal of Minerals,Metallurgy and Materials 2013年第6期20卷 529-534页

作者： Mehdi Haj Hojjatollah Mansouri reza Vafaei Golam reza ebrahimi Ali Kanani Department of Materials Engineering Malek Ashtar University of Technology Department of Materials and Polymer Engineering Faculty of Engineering Hakim Sabzevari University

The hot compression behavior of AISI 321 ll00~C and the strain rates of 0.01-1 s-1 using a Baehr austenitic stainless steel was studied at the temperatures of 950- DIL-805 deformation dilatometer. The hot deformation equations and the relationship between hot deformation parameters were obtained. It is found that strain rate and deformation temperature significantly influence the flow stress behavior of the steel. The work hardening rate and the peak value of flow stress increase with the decrease of deformation temperature and the increase of strain rate. In addition, the activation energy of deformation （Q） is calculated as 433.343 kJ/mol. The microstructural evolution during deformation indicates that, at the temperature of 950~C and the strain rate of 0.01 s-1, small circle-like precipitates form along grain boundaries; but at the temperatures above 950~C, the dissolution of such precipitates occurs. Energy-dispersive X-ray analyses indicate that the precipitates are complex carbides of Cr, Fe, Mn, Ni, and Ti.

关键词： austenitic stainless steel deformation constitutive equations microstructural evolution activation energy

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

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