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Mixing and segregation of solid particles in a conical spouted bed： Effect of particle size and density

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Particuology 2017年第3期15卷 132-140页

作者： M. Kiani M.R. Rahimi s.h. hosseini G. Ahmadi Department of Chemical Engineering Faculty of Engineering Yasouj University Yasouj lran Department of Chemical Engineering Faculty of Engineering llam University Ilam 69715-516 Iran Department of Mechanical and Aeronautical Engineering Clarkson University Potsdam NY 13699-5725 USA

In this work, the mixing and segregation of binary mixtures of particles with different sizes and densities in a pseudo-2D spouted bed were studied experimentally. A binary mixture of solid particles including sand, gypsum, and polyurethane was used. To determine the particles mass fraction, and their mixing and segregation in the bed, an image-processing technique was developed and used. Important hydrodynamic parameters, such as the axial and radial segregation profiles of the solid particles, were measured. The effects of air velocity, particle size, and particle mass fraction were also evaluated. The flow regime in the spouted bed and the time required for reaching the equilibrium state of the solid particles were discussed. The results showed that the segregation of solid particles and the time to equilibrium both decreased when the air velocity increased to much larger than the minimum spouting velocity. The axia! segregation increased with the diameter ratio of the particles. Upon completion of the test, coarse particles were concentrated mainly in the spout region, while fine particles were aggregated in the annulus region. Examination of the flow pattern in the spouted bed showed that the particles near the wall had longer flow paths, while those near the spout region had shorter flow paths.

关键词： Experimental segregation Binary particles 2D spouted bed

Dynamic stress concentration in an infinitely long cylindrical cavity due to a point s.h.rical source embedded within a fluid-saturated poroelastic formation of infinite extent

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 139-156页

作者： h.hosseini O.BALILAshAKI Department of Mechanical Engineering Faculty of EngineeringGolestan University

The effects of a harmonically exciting monopole source on an infinitely long cylindrical cavity embedded entirely within a fluid-saturated poroelastic formation of infinite extent are examined theoretically. It is assumed that the source is located outside the cavity at a specified distance from the borehole axis. The magnitudes of the hoop and radial stresses beside the pore pressures exerted on the interface and inside the porous medium surrounding the borehole are calculated and discussed. Biot's poroelastic modeling along with three types of boundary conditions for the cylindrical interface including the ideal fluid, empty borehole, and rigid inclusion with a hard boundary is employed for the analysis. Utilizing a proper translational addition theorem for expressing the incident s.h.rical wave in terms of cylindrical wave expansions, the proposed boundary conditions at the interface are satisfied. stresses are formulated by means of wave potential functions in a three-dimensional(3D) manner. The effects of the frequency and the radial distance between the source and borehole on the induced stresses are examined for the first cylindrical modes over frequency spectra. Two permeability conditions for the interface and three types of soils for the porous formation are considered throughout the analysis. To give an overall outline of the study, a numerical example is presented. The results clearly indicate that the distance is a key parameter and has considerable effects on the induced stress values. In addition, the interface permeability condition and soil characteristics play an important role in determining the dynamic response of the borehole. Finally,the obtained results are compared with the relevant analyses existing in the literature for some limit cases, and good agreement is achieved.

关键词：

ON ThE GLOBAL sTABILITY CONJECTURE OF ThE GENOTYPE sELECTION MODEL

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Acta Mathematica scientia 2011年第2期31卷 512-528页

作者： s.h. saker Department of Mathematics King Saud University Department of Mathematics Faculty of Science Mansoura University

In 1994, Grove, Kocic, Ladas, and Levin conjectured that the local stability and global stability conditions of the fixed point -y= 1/2 in the genotype selection model should be equivalent. In this article, we give an affirmative answer to this conjecture and prove that local stability implies global stability. some illustrative examples are included to demonstrate the validity and applicability of the results.

关键词： Local stability global stability discrete genotype selection model

Effect of temperature on pull-in voltage and nonlinear vibration behavior of nanoplate-based NEMs under hydrostatic and electrostatic actuations

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Acta Mechanica solida sinica 2017年第2期30卷 174-189页

作者： Farzad Ebrahimi s.h.s.hosseini Department of Mechanical Engineering Faculty of Engineering Imam Khomeini International University qazvinIran

This paper deals with the study of the temperature effect on the nonlinear vibration behavior of nanoplate-based nano electromechanical systems（NEMs） subjected to hydrostatic and electrostatic actuations. Using Eringen＇s nonlocal elasticity and Gurtin–Murdoch theory, the nonlocal plate model is derived through hamilton＇s principle. The governing equation which is extremely nonlinear due to the geometrical nonlinearity and electrostatic attraction forces is solved numerically using the differential quadrature method（DQM）. The accuracy of the present method is veriied by comparing the obtained results with the experimental data and those in the literature and very good agreement is obtained. Finally a comprehensive study is carried out to determine the inluence of temperature on the nonlinear vibration characteristics of NEMs made of two different materials including aluminum（Al）and silicon（si） and some conclusions are drawn.

关键词： small scale effect Nano electromechanical system Nonlinear vibration Temperature effect Pull-in voltage

self-propagating high temperature synthesis of Mosi_2 matrix composites

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Rare Metals 2006年第3期25卷 225-230页

作者： Akhtar Farid s.h. Islam Materials science and Engineering s.h.ol State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China

Mosi2 is presently regarded as the most important material for electrical heating and as one with huge potential for high temperature structural uses. Mosi2 and Mosi2 matrix composites were prepared by self-propagating high temperature synthesis （shs）. Pure Mosi2 was obtained and a compound of Mosi2 and Wsi2was synthesized in the form of predominant solid solution （Mo,W）si2. By adding aluminum of 5.5 at.% to Mo-si, the crystal structure of Mosi2 changed into a mixture of tetragonal Cllb Mosi2and hexagonal C40 Mo（si,Al）2. The （Mo,W）si2-Mo（si,Al）2-W（si,Al）2 composite materials were synthesized by adding aluminum of 5.5 at.% to Mo-W-si. however, if the amount of the added aluminum was not larger than 2.5 at.%, it did not have any significant effect. shs is an effective technology for synthesis of Mosi2 and Mosi2 matrix composites.

关键词： powder metallurgy Mosi2 matrix composites self-propagating high temperature synthesis molybdenumtungsten disilicide molybdenum aluminosilicide

Effect of Gaussian size distribution width on minimum fluidization velocity in tapered gas–solid fluidized beds

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Particuology 2022年第7期20卷 71-84页

作者： Mojtaba Rasteh Goodarz Ahmadi s.h.hosseini Department of Chemical Engineering Hamedan University of TechnologyHamedanP.O.Box 65155-579Iran Department of Mechanical and Aeronautical Engineering Clarkson UniversityPotsdamNY 13699-5725USA Department of Chemical Engineering Ilam UniversityIlam 69315-516Iran

This paper investigated the effect of Gaussian distribution width,average particle diameter,particle loading,and the tapered angle on minimum fluidization velocity(U_(mf))by conducting extensive experiments in tapered fluidized *** powders with Gaussian size distribution and different distribution widths were used in the *** increase in U_(mf)with increasing the average particle diameter,particle loading,and the tapered angle was *** was also a nonmonotonic behavior of Umf as the Gaussian distribution width *** empirical correlation including dimensionless groups for predicting Umf in tapered beds was developed in which the effect of distribution width was *** proposed correlation predictions were in good agreement with the experimental data,with a maximum deviation of 16.5%and average and standard deviations of,respectively,6.4%and 7.4%.The proposed correlation was also compared with three earlier models,and their accuracy was discussed.

关键词： Tapered fluidized bed Minimum fluidization velocity Gaussian size distribution Distribution width Dimensional analysis

Ideals Whose First Two Betti Numbers Are Close

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Algebra Colloquium 2015年第4期22卷 671-676页

作者： Keivan Borna s.h. hassanzadeh Faculty of Mathematical sciences and Computer Kharazmi University Tehran Iran School of Mathematics Institute for Research in Fundamental Sciences (IPM) Tehran Iran Faculty of Mathematical sciences and Computer Kharazmi University Tehran Iran Institute of Mathematics Universidade Federal de Rio de Janeiro Brasil

For an ideal I of a Noetherian local ring （R, m, k） one hasβR1（I） -β0R（I） ≥-1. It is demonstrated that some residual intersections of an ideal I for whichβ1R（I） -β0R（I） = -1 or 0 are perfect.

关键词： Betti numbers linlkage theory perfect Gorenstein ideals residual intersection

Investigation of Micro Formability of Bulk Amorphous Alloy in the supercooled Liquid state Based on Fluid Flow and Finite Element Analysis

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Journal of Materials science & Technology 2009年第2期25卷 277-280页

作者： M. Cheng s.h. Zhang Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

Research results on the viscous flow deformation behavior of bulk amorphous alloy in different systems are reviewed. The material exhibits an ideal Newtonian fluid at a high temperature. Analytical solution of lamellar fluid flow behavior is used to discuss the viscous flow behavior of the bulk amorphous alloy in the supercooled liquid state. A material model, which describes such deformation behavior of Mg6oCusoYlo amorphous alloy, is introduced into the finite element method of microformin8 process. surface feature size was investigated and found not sensitive to the micro formability. Bulk amorphous alloy may possibly be applied to microelectro-mechanical-systems （MEMs） fabrication.

关键词： Bulk amorphous alloy supercooled liquid state Micro formability Lamellar fluid flow

Theoretical approaches to alpha decay half-lives of super-heavy nuclei

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Chinese Physics C 2017年第6期41卷 69-74页

作者： s. s. hosseini h. hassanabadi Physics Department Shahrood University of Technology Shahrood Iran

We consider the systematics of α-decay half-lives of super-heavy nuclei versus the decay energy and the total α-kinetic energy. We calculate the half-lives using the experimental Qα values. The computed half-lives are compared with the experimental data and with existing empirical estimates and are found to be in good agreement. Also, we obtain α-preformation factors from the ratio between theoretical and experimental results for some super- heavy nuclei and evaluate the standard deviation. The results indicate the acceptability of the approach.

关键词： alpha decay super heavy nuclei (shN) half-life preformation factor