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Influence of the roughness and shape of quartz particles on their flotation kinetics

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International Journal of Minerals,Metallurgy and Materials 2012年第4期19卷 284-289页

作者： Mehdi Rahimi Fahimeh dehghani Bahram Rezai mohammad Reza Aslani Department of Mining and Metallurgical Engineering Amirkabir University of Technology Department of Mining Engineering Science and Research Branch Islamic Azad University

Surface roughness and shape play an important role on the behavior of particles in various processes such as flotation. In this re- search, the influence of different grinding methods on the surface roughness and shape characteristics of quartz particles as well as the effect of these parameters on the flotation of the particles was investigated. The surface roughness of the particles was determined by measuring their specific surface area via the gas adsorption method. The shape characteristics of the particles were measured and calculated by images obtained by scanning electron microscopy via an image analysis system. The flotation kinetics was determined using a laboratory flotation cell. The results showed that the particles of rod mill products have higher roughness and elongation ratio and lower roundness than the parti- cles of ball mill products. The flotation kinetics constant of the particles increased with their surface roughness increasing. Particles with higher elongation and lower roundness indicated higher floatability. In addition, the influence of the surface roughness on the flotation kinet- ics was greater than that of shape parameters.

关键词： flotation kinetics quartz shape parameters surface roughness

Ab initio investigation of the structural and unusual electronic properties of α-CuSe (klockmannite)

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Chinese Physics B 2013年第12期22卷 402-409页

作者： Ali Reza Shojaei Zahra Nourbakhsh Aminollah Vaez mohammad dehghani Physics Department Faculty of Science University of Isfahan Physics Department Technical and Vocational University-Mohajer Center

In this article, a computational analysis has been performed on the structural properties and predominantly on the electronic properties of the α-CuSe （klockmannite） using density functional theory. The studies in this work show that the best structural results, in comparison to the experimental values, belong to the PBEsol-GGA and WC-GGA functionals. However, the best results for the bulk modulus and density of states （DOSs） are related to the local density approximation （LDA） functional. Through utilized approaches, the LDA is chosen to investigate the electronic structure. The results of the electronic properties and geometric optimization of α-CuSe respectively show that this compound is conductive and non-magnetic. The curvatures of the energy bands crossing the Fermi level explicitly reveal that major charge carriers in CuSe are holes, whose density is estimated to be 0.86×1022 hole/cm3. In particular, the Fermi surfaces in the first Brillouin zone demonstrate interplane conductivity between （001） planes. Moreover, the charge carriers among them are electrons and holes simultaneously. The conductivity in CuSe is mainly due to the hybridization between the d orbitals of Cu atoms and the p orbitals of Se atoms. The former orbitals have the dual nature of localization and itinerancy.

关键词： klockmannite α-CuSe structural properties electronic properties

Behavior Analysis of Biomimetic Soft Bending Actuators in Free Motion and Contact

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Journal of Bionic Engineering 2023年第3期20卷 967-981页

作者： mohammad hadi Namdar Ghalati Sepideh Akbari Hamed Ghafarirad mohammad Zareinejad Department of Mechanical Engineering Amirkabir University of TechnologyTehran***Iran New Technologies Research Center(NTRC) Amirkabir University of TechnologyTehran***Iran

Bioinspired Soft Bending Actuators (SBA) are increasingly being used in rehabilitation, assistant robots, and grippers. Despite many investigations on free motion modeling, understanding how these actuators interact with the environment requires more detailed research. It is caused by high compliance and nonlinearity of bioinspired soft material, which leads to serious challenges in contact conditions. In this paper, a continuous deformation analysis is presented to describe the free motion nonlinear behavior of the actuator. Based on the achieved result, this study proposes static modeling of SBA affected by a concentrated external force. For this purpose, the finite rigid element method is utilized, which is based on discretizing the actuator into smaller parts and assuming these parts as rigid serial links connected by nonlinear torsional springs. To verify the proposed model, two kinds of forces are considered to be acting on the actuator, i.e. following force and constant direction force. In addition, the effect of gravity on the actuator configuration is also investigated. The validity of the model has been demonstrated through experiments in free motion, contact conditions and the presence of gravity. It generally shows that the prediction error of robot configuration is lower than 7.5%.

关键词： Biomimetic soft bending actuator Static modeling Contact Force constraints Rigid finite element

Optimized Fuzzy Controller for MPPT of Grid-connected PV Systems in Rapidly Changing Atmospheric Conditions

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Journal of Modern Power Systems and Clean Energy 2021年第2期9卷 376-383页

作者： Majid dehghani mohammad Taghipour Gevork B.Gharehpetian Mehrdad Abedi the Department of Electrical Engineering Amirkabir University of TechnologyTehranIran

Due to nonlinear behavior of power production of photovoltaic(PV)systems,it is necessary to apply the maximum power point tracking(MPPT)techniques to generate the maximum *** conventional MPPT methods do not function properly in rapidly changing atmospheric *** this study,a fuzzy logic controller(FLC)optimized by a combination of particle swarm optimization(PSO)and genetic algorithm(GA)is proposed to obtain the maximum power point(MPP).The proposed FLC uses the ratio of power variations to voltage variations and the derivative of power variations to voltage variations as inputs and uses the duty cycle as the *** range of changes in fuzzy membership functions and fuzzy rules are proposed as an optimization problem optimized by the *** proposed design is validated for MPPT of a PV system using MATLAB/Simulink *** results indicate a better performance of the proposed FLC compared to the common methods.

关键词： Photovoltaic(PV) maximum power point tracking(MPPT) fuzzy particle swarm optimization(PSO) genetic algorithm(GA) incremental conductance perturb and observe

Improvement in IBC-silicon solar cell performance by insertion of highly doped crystalline layer at heterojunction interfaces

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Chinese Physics B 2017年第10期26卷 508-514页

作者： hadi Bashiri mohammad Azim Karami Shahramm mohammadnejad School of Electrical Engineering Iran University of Science &Technology (IUST)

By inserting a thin highly doped crystalline silicon layer between the base region and amorphous silicon layer in an interdigitated back-contact （IBC） silicon solar cell, a new passivation layer is investigated. The passivation layer performance is characterized by numerical simulations. Moreover, the dependence of the output parameters of the solar cell on the additional layer parameters （doping concentration and thickness） is studied. By optimizing the additional passivation layer in terms of doping concentration and thickness, the power conversion efficiency could be improved by a factor of 2.5%, open circuit voltage is increased by 30 mV and the fill factor of the solar cell by 7.4%. The performance enhancement is achieved due to the decrease of recombination rate, a decrease in solar cell resistivity and improvement of field effect passivation at heterojunction interface. The above-mentioned results are compared with reported results of the same conventional interdigitated back-contact silicon solar cell structure. Furthermore, the effect of a-Si：H/c-Si interface defect density on IBC silicon solar cell parameters with a new passivation layer is studied. The additional passivation layer also reduces the sensitivity of output parameter of solar cell to interface defect density.

关键词： IBC silicon solar cells interface layer recombination interface defect density

Fracture analyses of different pre-holed concrete specimens under compression

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Acta Mechanica Sinica 2015年第6期31卷 855-870页

作者： hadi Haeri Alireza Khaloo mohammad Fatehi Marji Department of Civil Engineering Sharif University of Technology Member of National Elites Foundation Center of Excellence in Structure and Earthquake Engineering Sharif University of Technology Mine Exploitation Engineering Department Faculty of Mining and Metallurgy Yazd University

Crack propagation processes in specially prepared concrete discs and rectangular specimens containing a single cylindrical hole or multiple holes of varying diameters have been studied both experimentally and numerically. In this research, the cracks coalescence paths in Brazilian disc and rectangular specimens made from rock-like material containing multi-holes are investigated. These concrete specimens are specially prepared from an appropriate mixture of Portland Pozzolana Cement （PPC）, fine sands, and water. The pre-holed Brazilian discs and rectangular specimens are experimentally tested under compression. The breakage load in the ring type disc specimens containing an axial hole with varying diameters is measured and the distribution of the induced lateral stress is obtained. The mechanism of cracks propagation in the wall of the ring type specimens is also stud- ied. In the case of multi-hole Brazilian disc and rectangular specimens, the cracks propagation and cracks coalescence are also investigated. These experiments are numerically modeled by a modified higher order displacement discontinuity method. It has been shown that the corresponding experimental and numerical results are in good agreement with each other. The results presented in this research vali date the accuracy and applicability of these crack analyses procedures.

关键词： Concrete rings Pre-holed Brazilian disc ·Rectangular specimens Crack analyses Coalescence ·Induced lateral stress

Genetic and Genotype × Environment Interaction Effects for Appearance Quality of Rice

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Agricultural Sciences in China 2009年第8期8卷 891-901页

作者： Sharifi Peyman dehghani Hamid Mumeni Ali Moghaddam mohammad Department of Plant Breeding Faculty of Agriculture Tarbiat Modares University Rice Research Institute of Iran (RRII) Department of Agronomy and Plant Breeding Faculty of Agriculture Tabriz University

This study was conducted to generate genetic information in rice varieties based on a complete diallel crosses over two years. The results indicated that genotype effect was significant for all traits. Genotype × environment interaction effects were significant only for cooked grain length （CGL） and cooked grain shape （CGSH）. General combining ability （GCA） and specific combining ability （SCA） effects were significant for entire traits, which indicated the important roles of both additive and non-additive gene actions. GCA x environment interaction effects were significant for CGL, CGSH and grain elongation index （GEI）. In the controlling of the inheritance of milled grain shape （GSH）, milled grain width （MGW）, GEI, milled grain length （MGL）, CGSH and cooked grain width （CGW）, the additive gene effects were more important than non-additive one. The average degree of dominance was within the range of partial dominance for all of the traits. The narrow-sense heritability was ranged from 0.65 （GSH） to 0.36 （CGL）. GCA effects were significant for all of the parents in milled grain length and it was significant for some of the parents in other traits. The crosses of Deilmani × IRFAON-215 exhibited significant SCA for GEI. The positive mean of heterosis was observed for CGW. The highest maximum values of heterosis were revealed in GEI, flowed by GSH, MGW and CGW. GCA and MPV were significantly and positively correlated together for all traits.

关键词： appearance quality diallel analysis genetic main effects environment interaction milling quality rice

Language Education Optimization: A New Human-Based Metaheuristic Algorithm for Solving Optimization Problems

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Computer Modeling in Engineering & Sciences 2023年第8期136卷 1527-1573页

作者： Pavel Trojovsky mohammad dehghani Eva Trojovská Eva Milkova Department of Mathematics Faculty of ScienceUniversity of Hradec KrálovéHradec Králové50003Czech Republic Department of Applied Cybernetics Faculty of ScienceUniversity of Hradec KrálovéHradec Králové50003Czech Republic

In this paper,based on the concept of the NFL theorem,that there is no unique algorithm that has the best performance for all optimization problems,a new human-based metaheuristic algorithm called Language Education Optimization(LEO)is introduced,which is used to solve optimization *** is inspired by the foreign language education process in which a language teacher trains the students of language schools in the desired language skills and *** is mathematically modeled in three phases:(i)students selecting their teacher,(ii)students learning from each other,and(iii)individual practice,considering exploration in local search and exploitation in local *** performance of LEO in optimization tasks has been challenged against fifty-two benchmark functions of a variety of unimodal,multimodal types and the CEC 2017 test *** optimization results show that LEO,with its acceptable ability in exploration,exploitation,and maintaining a balance between them,has efficient performance in optimization applications and solution *** efficiency in optimization tasks is compared with ten well-known metaheuristic *** of the simulation results show that LEO has effective performance in dealing with optimization tasks and is significantly superior andmore competitive in combating the compared *** implementation results of the proposed approach to four engineering design problems show the effectiveness of LEO in solving real-world optimization applications.

关键词： Optimization language education exploration exploitation metaheuristic algorithm

A robust subband adaptive filter algorithm for sparse and block-sparse systems identification

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Journal of Systems Engineering and Electronics 2021年第2期32卷 487-497页

作者： ZAHRA Habibi hadi Zayyani mohammad Shams Esfand Abadi Research Institute for Information and Communications Technologies Academic Center for EducationCulture and ResearchTehran ***Iran Department of Electrical and Computer Engineering Qom University of TechnologyQom 371951519Iran Faculty of Electrical Engineering Shahid Rajaee Teacher Training UniversityTehran ***Iran

This paper presents a new subband adaptive filter(SAF)algorithm for system identification scenario under impulsive interference,named generalized continuous mixed p-norm SAF(GCMPN-SAF)*** proposed algorithm uses a GCMPN cost function to combat the impul-sive *** further accelerate the convergence rate in the sparse and the block-sparse system identification processes,the proportionate versions of the proposed algorithm,the L0-norm GCMPN-SAF(L0-GCMPN-SAF)and the block-sparse GCMPN-SAF(BSGCMPN-SAF)algorithms are also ***,the convergence analysis of the proposed algorithm is *** results show that the proposed algorithms have a better performance than some other state-of-the-art algorithms in the literature with respect to the convergence rate and the tracking capability.

关键词： subband adaptive filter(SAF) generalized continuous mixed p-norm(GCMPN) sparse system block-sparse system impulsive interference