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Modeling Submicron Particles Collection in Laminar Forced Convection Gas Flow by a Rectangular Venturi Scrubber

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Open Journal of Air Pollution 2016年第1期5卷 10-26页

作者： Serge Wendsida igo Kokou N’wuitcha Belkacem Zeghmati Xavier Chesneau Département Energie Institut de Recherche en Sciences Appliquées et Technologies (IRSAT/CNRST) Ouagadougou Burkina Faso GPTE-LES Département de Physique Université de Lomé Lomé Togo Laboratoire de Mathématiques et Physique des Systèmes (LAMPS) Perpignan France

Venturi scrubbers are usually used for large particles cleaning in turbulent gaseous flow. in this work, submicron particles scrubbing in laminar forced convection dusty air flow in a rectangular venturi scrubber have been numerically simulated. Hydrodynamics effects and scrubbing process are investigated in detail. Results are presented as flow velocity, axial pressure, streamlines pattern, particles and droplets mass fraction profile, and collect efficiency. They show that venturi scrubbers can be efficient for submicron particles scrubbing. in fact, a better collect efficiency is obtained at high particles-droplets residence time, high ratio droplets concentration/particles concentration, low venturi diameter ratioand low Reynolds numbers. There is a critical Reynolds number value for which the collect efficiency becomes very low and tends to be constant.

关键词： Venturi Scrubber Submicron Particles Diffusion Laminar Flow Collect Efficiency

MHD flow and heat transfer of a hybrid nanofluid past a permeable stretching/shrinking wedge

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Applied Mathematics and Mechanics(English Edition) 2020年第3期41卷 507-520页

作者： i.WAiNi A.iSHAK i.POP Fakulti Teknologi Kejuruteraan Mekanikal dan Pembuatan Universiti Teknikal Malaysia MelakaHang Tuah JayaDurian Tunggal 76100MelakaMalaysia Department of Mathematical Sciences Faculty of Science and TechnologyUniversiti Kebangsaan MalaysiaUKM Bangi 43600SelangorMalaysia Department of Mathematics Babe¸s-Bolyai UniversityCluj-Napoca 400084Romania

The steady flow and heat transfer of a hybrid nanofluid past a permeable stretching/shrinking wedge with magnetic field and radiation effects are studied. The governing equations of the hybrid nanofluid are converted to the similarity equations by techniques of the similarity transformation. The bvp4c function that is available in MATLAB software is utilized for solving the similarity equations numerically. The numerical results are obtained for selected different values of parameters. The results discover that two solutions exist, up to a certain value of the stretching/shrinking and suction strengths. The critical value in which the solution is in existence decreases as nanoparticle volume fractions for copper and wedge angle parameter increase. it is also found that the hybrid nanofluid enhances the heat transfer rate compared with the regular nanofluid. The reduction of the heat transfer rate is observed with the increase in radiation parameter. The temporal stability analysis is performed to analyze the stability of the dual solutions, and it is revealed that only one of them is stable and physically reliable.

关键词： dual solution hybrid nanofluid stretching/shrinking wedge magnetic field radiation stability analysis

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俏皮的多彩世界——贝里奥萨尔幼儿园

现代装饰 2014年第1期 68-75页

作者： Javier Larraz iigo Beguiristain iaki Bergera 姜敏华 Javier Larraz Arquitecto iigo Beguiristain工作室 iaki Bergera photography

依据Louis ***的建筑哲学理念,当一个知道自己是老师的人和一群不知道自己是学生的人在一棵树下讨论他毕生所学的时候,世上第一所学校便诞生了。正如那些学生一样,3岁以下的孩子学习其实都是处于凭直觉和无意识状态。对照Kahn的故事,人... 详细信息

依据Louis ***的建筑哲学理念,当一个知道自己是老师的人和一群不知道自己是学生的人在一棵树下讨论他毕生所学的时候,世上第一所学校便诞生了。正如那些学生一样,3岁以下的孩子学习其实都是处于凭直觉和无意识状态。对照Kahn的故事,人们可能会很想弄清那棵树即建筑在教学实践中扮演的角色。就幼儿园来说,本案设计师十分坚信建筑所带来的教学价值,以及建筑创造机会帮助孩子培养这一年龄段应有的可开导性、魅力气质以及安全意识等能力的作用。这个幼儿园位于雷焦艾米利亚,属于意大利市属学校。长方形的场地两端分别是大的活动广场,中部还有一个室内的开放空间供学生使用。教室和功能房布置在开放空间之内,因此室内获得了良好的通风和采光。高大的天窗为室内带来戏剧性的光影。建筑外部绚丽多彩的竖向格栅俏皮地划定了幼儿园的空间,并与内部宁静柔和的大气空间形成对比。控制得当的各处场所成为了孩子们理想的嬉戏和活动场地。布局的透明性也使得

关键词：幼儿园长方形开放空间建筑天井矿井内部空间卫生间

Complex Maxwell's equations

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Chinese Physics B 2013年第3期22卷 111-116页

作者： A.i.Arbab Department of Physics Faculty of ScienceUniversity of KhartoumKhartoum 11115Sudan

A unified complex model of Maxwell＇s equations is *** wave nature of the electromagnetic field vector is related to the temporal and spatial distributions and the circulation of charge and current densities.A new vacuum solution is obtained,and a new transformation under which Maxwell＇s equations are invariant is *** transformation extends ordinary gauge transformation to include charge-current as well as scalar-vector *** electric dipole moment is found to be related to the magnetic charges,and Dirac＇s quantization is found to determine an uncertainty relation expressing the indeterminacy of electric and magnetic *** generalize Maxwell＇s equations to include longitudinal waves.A formal analogy between this formulation and Dirac＇s equation is also discussed.

关键词： Maxwell's equations duality transformations magnetic charge(monopole)

Dynamic responses of a sediment-filled valley with a fluid layer subject to incident waves

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Earthquake Engineering and Engineering Vibration 2011年第2期10卷 175-185页

作者： Wen-i Liao Taipei University of Technology (NTUT)

The diffraction of elastic waves by a sedimentary valley in a homogeneous elastic half-space is studied in this paper. The sediment-filled valley is composed of a fluid layer over a soft soil deposit whose characteristics may be significant and should be carefully considered when designing long span bridges with high piers. The method of analysis adopted in the paper is to decompose the problem into an interior region and an exterior region. in the exterior region, the scattered wave fields are constructed with the linear combinations of two independent sets of Lamb＇s singular solutions, i.e., the integral solutions for two concentrated surface loads in two directions; and their derivatives are used to represent the scattered wave fields. A technique is proposed to calculate the integrals in the wave-number domain based on the method of steepest descent. For the interior region, the wave fields for the fluid layer and soft soil deposit are expressed in terms of wave functions which satisfy the equation of motion. The continuity condition at the interface of the media is satisfied in the least square sense. The effects of geometric topography, soil amplification and fluid layer subject to different types of incident harmonic plane waves are analyzed and discussed..

关键词： sedimentary valley scattered wave least square

influence of the chromium and ytterbium co-doping on the photoluminescence of zinc selenide crystals

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Journal of Rare Earths 2014年第10期32卷 938-945页

作者： i.Radevici Wihuri Physical Laboratory Department of Physics and AstronomyUniversity of Turku Faculty of Physics and Engineering Moldova State University

The luminescent properties of ZnSe, ZnSe：Cr（0.05 at.% Cr）, ZnSe：Yb（0.03 at.% Yb） and ZnSe：Cr：Yb（0.05 at.% Cr, 0.05 at.% Yb） crystals, doped during the growth process by the chemical vapor transport method, were studied within the temperature interval of 6–300 K. At the 6 K temperature in the visible spectral range 2 bands were observed： a band in the excitonic spectral region and a band of self-activated luminescence. it was shown that co-doping of zinc selenide crystals with the chromium and ytterbium led to the combination of the impurities influence on the photoluminescent properties. At the liquid helium temperature in the middle infrared range of the spectra of the ytterbium and chromium co-doped crystal a band with the maximum localized at 1.7μm was observed, which was overlapped with a complex band in the middle-iR spectral range, characteristic for the chromium doped ZnSe crystals. On the basis of obtained data an interaction mechanism of the chromium and ytterbium co-doping impurities was proposed. Guided by the existent model of the ytterbium ion incorporation in the selenide sublattice of the ZnSe crystals, an assumption about stabilization of single charged chromium ions in the zinc sublattice crystal nodes, by means of formation of the local charge compensating clusters, was made. it was assumed that the resonant energy transfer from one chromium ion to another,which led to the concentration quenching of the iR emission in the ZnSe：Cr PL spectra, would lead to the broadening of the iR emission in the spectra of ytterbium and chromium co-doped zinc selenide crystals.g

关键词： ZnSe luminescence co-doping defects Cr Yb rare earths

Crossover of large to small radius polaron in ionic crystals

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Chinese Physics B 2016年第11期25卷 434-440页

作者： M i Umo Department of Physics University of Calabar PMB 1115 Nigeria

The crossover of large to small radius polaron is studied in terms of the inverse-relaxation time and *** is found that the small radius polaron exists at higher temperature than the large radius polaron.A formula which relates the inverse-relaxation time to the ratio of arbitrary temperature and Debye temperature of the crystal is *** polaron crossover temperatures in NaCl and KBr are found from plotted *** straight line emerging at the Debye temperature T_d of a graph reflects the increase of the inverse relaxation time for increasing temperature up to the collapse of the small radius *** relationship between the small and large radius polarons is found and known ratios of the effective and the bare masses of the electrons for the two substances are used to validate our *** small radius polaron＇s mass is later compared with the mass obtained from the hopping formula and is found to be approximately ***,we point out that the crossover temperature is material-specific since it depends on the Debye and the effective dielectric function.

关键词： relaxation radius crossover inverse straight ionic validate arbitrary phonon dielectric

The quantum Hall's effect:A quantum electrodynamic phenomenon

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Chinese Physics B 2012年第12期21卷 444-450页

作者： A.i.Arbab Department of Physics Faculty of ScienceUniversity of Khartoum

We have applied Maxwell＇s equations to study the physics of quantum Hall＇s effect. The electromagnetic properties of this system are obtained. The Hall＇s voltage, VH ---- 27rh2ns/em, where ns is the electron number density, for a 2- dimensional system, and h ---- 27rh is the Planck＇s constant, is found to coincide with the voltage drop across the quantum capacitor. Consideration of the cyclotronic motion of electrons is found to give rise to Hall＇s resistance. Ohmic resistances in the horizontal and vertical directions have been found to exist before equilibrium state is reached. At a fundamental level, the Hall＇s effect is found to be equivalent to a resonant LCR circuit with LH = 2π m/e2ns and CH -= me2/π2h2ns satisfying the resonance condition with resonant frequency equal to the inverse of the scattering （relaxation） time, τs. The Hall＇s resistance is found to be RH = √LH/CH The Hall＇s resistance may be connected with the impedance that the electron wave experiences when it propagates in the 2-dimensional gas.

关键词： quantum Hall effect Maxwell equations electromagnetism

Optimal Combined Heat and Power Economic Dispatch Using Stochastic Fractal Search Algorithm

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Journal of Modern Power Systems and Clean Energy 2020年第2期8卷 276-286页

作者： Muwaffaq i.Alomoush the Department of Electrical Power Engineering Hijjawi Faculty for Engineering TechnologyYarmouk UniversityIrbidJordan

Combined heat and power(CHP)generation is a valuable scheme for concurrent generation of electrical and thermal *** interdependency of power and heat productions in CHP units introduces complications and non-convexities in their modeling and *** paper uses the stochastic fractal search(SFS)optimization technique to treat the highly non-linear CHP economic dispatch(CHPED)problem,where the objective is to minimize the total operation cost of both power and heat from generation units while fulfilling several operation interdependent limits and *** CHPED problem has bounded feasible operation regions and many local *** SFS,which is a recent metaheuristic global optimization solver,outranks many current reputable *** constraints of the CHPED is achieved by employing external penalty parameters,which penalize infeasible solution during the iterative *** confirm the strength of this algorithm,it has been tested on two different test systems that are regularly *** obtained outcomes are compared with former outcomes achieved by many different methods reported in literature of *** results of this work affirm that the SFS algorithm can achieve improved near-global solution and compare favorably with other commonly used global optimization techniques in terms of the quality of solution,handling of constraints and computation time.

关键词： Combined heat and power(CHP) economic dispatch global optimization metaheuristic algorithms non-convex optimization problem power systems stochastic fractal search