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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

Characterization of single-crystal fluorapatite nanoparticles synthesized via mechanochemical method

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Particuology 2011年第5期9卷 537-544页

作者： reza ebrahimi-Kahrizsangi Bahman Nasiri-Tabrizi Akbar Cham Materials Engineering Department Najafabad Branch Islamic Azad University

The synthesis of nanostructured fiuorapatite （FA; Calo（PO4）6F2） was explored from the starting materials of CaHPO4, Ca（OH）2, CaO, P205 and CaF2 via a mechanochemical process. In this research, the suitability of using the mechanochemical process to prepare a high crystalline phase of FA was studied. The characterization and structural features of the synthesized powders were evaluated using powder X-ray diffraction （XRD）, Fourier transform infrared spectroscopy （FT-IR）, energy dispersive X-ray spectroscopy （EDX）, scanning electron microscopy （SEM）, and transmission electron microscopy （TEM） techniques. The results from the structural studies indicate that the maximum lattice disturbance in the apatite structure after the mechanochemical process was at the （0 0 2） plane. Furthermore, the maximum particle size was below the crystallite size after 60 h of milling and subsequent thermal treatment at 600 ℃ for 1 h （heated up to 600 ℃ and kept for 1 h at this temperature）. We determined that this method gives rise to the single-crystal FA with an average size in the range of 25 ± 5 to 29 ± 9 rim. The present findings suggest that the solid-state reaction and appropriate thermal process simultaneously lead to the formation of nanostructured FA with spheroidal shape.

关键词： Fluorapatite Single-crystal Nanoparticles Mechanochemical Crystallinity

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

Effect of milling atmosphere on structural and magnetic properties of Ni-Zn ferrite nanocrystalline

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Chinese Physics B 2015年第4期24卷 481-490页

作者： Abdollah Hajalilou Mansor Hashim reza ebrahimi-Kahrizsangi Mohamad Taghi Masoudi Material Synthesis and Characterization Laboratory Institute of Advanced Technology (ITMA)Universiti Putra Malaysia Advanced Materials Research Center Materials Engineering Department Najafabad Branch Islamic Azad University

Powder mixtures of Zn, NiO, and Fe2O3 are mechanically alloyed by high energy ball milling to produce Ni-Zn ferrite with a nominal composition of Ni0.36Zn0.64Fe2O4. The effects of milling atmospheres （argon, air, and oxygen）, milling time （from 0 to 30 h） and heat treatment are studied. The products are characterized using x-ray diffractometry, field emission scanning electron microscopy equipped with energy-dispersive x-ray spectroscopy, and transmitted electron microscopy. The results indicate that the desired ferrite is not produced during the milling in the samples milled under either air or oxygen atmospheres. In those samples milled under argon, however, Zn/NiO/Fe2O3 reacts with a solid-state diffusion mode to produce Ni-Zn ferrite nanocrystalline in a size of 8 nm after 30-h-milling. The average crystallite sizes decrease to 9 nm and 10 nm in 30-h-milling samples under air and oxygen atmospheres, respectively. Annealing the 30-h-milling samples at 600℃ for 2 h leads to the formation of a single phase of Ni-Zn ferrite, an increase of crystallite size, and a reduction of internal lattice strain. Finally, the effects of the milling atmosphere and heating temperature on the magnetic properties of the 30-h-milling samples are investigated.

关键词： Ni-Zn ferrite nanocrystalline mechanical alloying milling atmosphere milling time magnetic property