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Numerical Solution of MHD Convection and Mass Transfer Flow of Viscous Incompressible Fluid about an Inclined Plate with Hall Current and Constant Heat Flux

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Journal of Applied Mathematics and Physics 2015年第12期3卷 1688-1709页

作者： Mohammad Wahiduzzaman Runu Biswas md. Eaqub Ali md. shakhaoath khan Ifsana Karim Mathematics Discipline Khulna University Khulna Bangladesh Mathematics Open School Bangladesh Open University Gazipur Bangladesh Department of Civil Engineering Sonargaon University Dhaka Bangladesh Discipline of Chemical Engineering The University of Newcastle Callaghan Australia

The present numerically study investigates the influence of the Hall current and constant heat flux on the Magneto hydrodynamic (MHD) natural convection boundary layer viscous incompressible fluid flow in the manifestation of transverse magnetic field near an inclined vertical permeable flat plate. It is assumed that the induced magnetic field is negligible compared with the imposed magnetic field. The governing boundary layer equations have been transferred into non-similar model by implementing similarity approaches. The physical dimensionless parameter has been set up into the model as Prandtl number, Eckert number, Magnetic parameter, Schmidt number, local Grashof number and local modified Grashof number. The numerical method of Nactsheim-Swigert shooting iteration technique together with Runge-Kutta six order iteration scheme has been used to solve the system of governing non-similar equations. The physical effects of the various parameters on dimensionless primary velocity profile, secondary velocity profile, and temperature and concentration profile are discussed graphically. Moreover, the local skin friction coefficient, the local Nusselt number and Sherwood number are shown in tabular form for various values of the parameters.

关键词： MHD Heat and Mass Transfer Hall Current Inclined Plate Constant Heat Flux

Unsteady Heat Transfer of Viscous Incompressible Boundary Layer Fluid Flow through a Porous Plate with Induced Magnetic Field

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Journal of Applied Mathematics and Physics 2016年第2期4卷 294-306页

作者： Ariful Islam Muhammad Minarul Islam Mahabur Rahman Lasker Ershad Ali md. shakhaoath khan Mathematics Discipline Khulna University Khulna Bangladesh Bangabandhu Sheikh Mujibur Rahman Science & Technology University Gopalgonj Bangladesh Discipline of Chemical Engineering University of Newcastle Callaghan Australia

Because of the great importance of thermal instability in nature, in chemical processes, in separation processes, in industrial applications as well as in geophysical and astrophysical engineering, the effect of thermal diffusion on the combined MHD heat transfer in an unsteady flow past a continuously moving semi-infinite vertical porous plate which is subjected to constant heat has been investigated numerically under the action of strong applied magnetic field taking into account the induced magnetic field. This study is performed for cooling problem with lighter and heavier particles. Numerical solutions for the velocity field, induced magnetic field as well as temperature distribution are obtained for associated parameters using the explicit finite difference method. The obtained results are also discussed with the help of graphs to observe effects of various parameters on the above mentioned quantities.

关键词： Heat Transfer Porous Medium Induced Magnetic Field Finite Difference Method

Viscous Dissipation and Radiation Effects on MHD Boundary Layer Flow of a Nanofluid Past a Rotating Stretching Sheet

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Applied Mathematics 2015年第3期6卷 547-567页

作者： M. Wahiduzzaman md. shakhaoath khan P. Biswas Ifsana Karim M. S. Uddin Mathematics Discipline Khulna University Khulna Bangladesh Discipline of Chemical Engineering The University of Newcastle Callaghan Australia

Viscous dissipation and radiative heat transfer in nanofluid with the influence of magnetic field over a rotating stretching surface has been investigated numerically. The steady laminar boundary layer flow is considered in this study. The governing boundary-layer equations are formulated and transformed into nonlinear ordinary coupled differential equations by using similarity variables. The governing equations are solved numerically using the Nactsheim-Swigert Shooting iteration technique together with the Runge-Kutta six order iteration schemes with the help of a computer programming language Compaq Visual Fortran 6.6a. The simulation results are presented graphically to illustrate influence of well-known parameters on the velocity, temperature and concentration distributions as well as skin-friction coefficient, Nusselt and Sherwood number at the sheet.

关键词： Nanofluid Viscous Dissipation Thermal Radiation Stretching Sheet Nactsheim-Swigert Shooting Iteration Technique

Status and prospects for symmetric organic redox flow batteries

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Journal of Energy Chemistry 2025年第1期100卷 125-143页

作者： md.Al Raihan C.Adam Dyker Department of Chemistry University of New Brunswick

As environmental concerns from fossil fuel consumption intensify, large-scale energy storage becomes imperative for the integration of renewable sources like wind, hydro, and solar with the electrical *** flow batteries, particularly those employing organic molecules, are positioned as a key technology for this purpose. This review explores the growing field of symmetric organic redox flow batteries(ORFBs) within this context. Unlike traditional asymmetric designs based on unique active materials for each electrode, symmetric ORFBs involve a single bipolar species for both electrodes. This review highlights the benefits of a symmetric design, and categorizes five distinct classes of organic bipolar molecules used in both aqueous and non-aqueous solvents. By providing a comprehensive overview of their cell cycling and performance characteristics, the strengths and weaknesses of the diverse categories of bipolar molecules are highlighted for both solvent systems, as are opportunities for future development. This should guide new research directions and advance the development of practical symmetric ORFBs.

关键词： Redox flow battery Symmetric battery Organic battery Aqueous electrolyte Non-aqueous electrolyte

Design and simulation to improve the structural efficiency of green light emission of GaN/InGaN/AIGaN light emitting diode

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Frontiers of Optoelectronics 2017年第4期10卷 370-377页

作者： Sakhawat HUSSAIN Tasnim ZERIN md. Ashik khan Department of Electrical and Electronic Engineering University of Dhaka Dhaka-1000 Bangladesh

This study considered the design of an efficient, high brightness polar InGaN/GaN light emitting diode （LED） structure with A1GaN capping layer for green light emission. The deposition of high In （〉 15%） composition within InGaN quantum well （QW） has limitations when providing intense green light. To design an effective model for a highly efficient InGaN green LEDs, this study considered the compositions of indium and aluminum for InxGal xN QW and AlyGal yN cap layers, along with different layer thicknesses of well, barrier and cap. These structural properties significantly affect different properties. For example, these properties affect electric fields of layers, polarization, overall elastic stress energy and lattice parameter of the structure, emission wavelength, and intensity of the emitted light. Three models with different composition and layer thicknesses are simulated and analyzed to obtain green light with in-plane equilibrium lattice parameter close to GaN （3.189 A ） with the highest oscillator strength values. A structure model is obtained with an oscillator strength value of 1.18 × 10-1 and least in-plane equilibrium lattice constant of 3.218 A. This emitter can emit at a wavelength of 540 nm, which is the expected design for the fabrication of highly efficient, bright green LEDs.

关键词： green light emitting diode (LED) latticeparameter oscillator strength InGaN quantum well (QW),A1GaN capping layer

Quasi-inverse Pendulum Model of 12 DoF Bipedal Walking

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International Journal of Automation and computing 2017年第2期14卷 179-190页

作者： M. Akhtaruzzaman Amir A. Shafie md. Raisuddin khan Department of Mechatronics Engineering Kulliyyah of Engineering International Islamic University Malaysia Kuala Lumpur 53100 Malaysia

This paper presents modeling of a 12-degree of freedom （DoF） bipedal robot, focusing on the lower limbs of the system, and trajectory design for walking on straight path. Gait trajectories are designed by modeling of center of mass （CoM） trajectory and swing foot ankle trajectory based on stance foot ankle. The dynamic equations of motion of the bipedal robot are derived by considering the system as a quasi inverted pendulmn （QIP） model. The direction and acceleration of CoM movement of the QIP model is determined by the position of CoM relative to the centre of pressure （COP）. To determine heel-contact and toe-off, two custom designed switches are attached with heel and toe positions of each foot. Four force sensitive resistor （FSR） sensors are also placed at the plantar surface to measure pressure that is induced on each foot while walking which leads to the calculation of CoP trajectory. The paper also describes forward kinematic （FIK） and inverse kinematic （IK） investigations of the biped model where Denavit-Hartenberg （D-H） representation and Geometric-Trigonometric （G-T） formulation approach are applied. Experiments are carried out to ensure the reliability of the proposed model where the links of the bipedal system follow the best possible trajectories while walking on straight path.

关键词： Humanoid robot quasi-inverse pendulum gait trajectory planning Anthropoid.

Options and Opportunities for Energy Management in Malaysian Grid Systems-Putrajaya as a Case Study

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Journal of Electronic Science and Technology 2018年第4期16卷 316-324页

作者： Aravind CV Umashankar Subramaniam md.Shahrukh Adnan khan md. Ibrahim Ibne Alam School of Engineering Taylor’s University Subang Jaya 47500 Malaysia Department of Energy and Power Electronics VIT University Vellore 632014 India University of Asia Pacific Dhaka 1205 Bangladesh

This paper presents an opportunity for energy management with an integrated photovoltaic and wind farm for the energy and economic aspects of the commercial area located in Putrajaya. The energy economy accession conforming to the wind speed, temperature, solar irradiation, and energy consumption on a daily basis is taken into consideration. Design analysis is done through the industry standard numerical tool. From the result analysis, the recommended ratio of renewable share minimizing stress to the electric grid is proposed. According to the solutions obtained from the numerical design tool, photovoltaic is recommended to be more energy efficient and economically viable in comparison of the fully crowded wind farm. From the proposed solutions, the photovoltaic is able to provide 51% of the energy consumed and it costs RM 0.365 per kW/h.

关键词： Cost grid Homer Pro photovoltaic park wind turbine farm

MOVPE Growth of In_xGa_(1-x)N(x～0.4) and Fabrication of Homo-junction Solar Cells

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Journal of Materials Science & Technology 2013年第2期29卷 128-136页

作者： md. Rafiqul Islam md. Rejvi Kaysir md. Jahirul Islam A. Hashimoto A. Yamamoto Department of Electrical and Electronic Engineering KUETKhulna 9203 Bangladesh Graduate School of Engineering University of Fukui 3-9-1 BunkyoFukui 910-8507 Japan

The metal organic vapor phase epitaxy （MOVPE） growth of indium gallium nitride （InGaN） has been discussed in detail towards the fabrication of solar cell. The InGaN film with In contents up to 0.4 are successfully grown by controlling the fundamental growth parameters such as the precursor gas flow rates, temperature etc. The formation of metallic In originates from the higher value （0.74） of trimethylindium/ （trimethylindium ＋ triethylgallium）（TMI/（TMI ＋ TEG）） molar ratio with low （4100） V/lll weight molar ratio while the lower value （0.2） of TMI/（TMI ＋ TEG） causes the phase separation. It is also necessary to control the growth rate and epitaxial film thickness to suppress the phase separation in the material. The crystalline quality of grown films is studied and it is found to be markedly deteriorated with increasing In content. The lattice parameters as well as the thermal expansion coefficient mismatch between GaN template and InGaN epi-layer are primarily considered as the reasons to deteriorate the film quality for higher In content. By using Ino.16Ga0.84N films, an n＋-p homo-junction structure is fabricated on 0.65 μm GaN template. For such a device, the response to the light illumination （AM 1.5） is observed with an open circuit voltage of 1.4 V and the short circuit current density of 0.25 mA/cm2. To improve the performance as well as increase solar photon capturing, the device is further fabricated on thick GaN template with higher In content. The In0.25Ga0.75N n＋-p junction solar cell is found better performance with an open circuit voltage of 1.5 V and the short circuit current density of 0.5 mA/cm2. This is the InGaN p-n homo-junction solar cell with the highest In content ever reported by MOVPE.

关键词： InGaN Metal organic vapor phase epitaxy (MOVPE) Growth Film quality Doping p-n junction

Regeneration mechanisms and therapeutic strategies for neuromuscular junctions in aging and diseases

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Neural Regeneration Research 2025年第1期20卷 193-194页

作者： Masashi Fujitani Abu md.Mamun Tarif Yoshinori Otani Department of Anatomy and Neuroscience Faculty of MedicineShimane UniversityShimaneJapan

The neuromuscular junction(NMJ)is an essential synaptic structure composed of motor neurons,skeletal muscles,and glial cells that orchestrate the critical process of muscle contraction(Li et al.,2018).The typical NMJ structure is classically described as having a“pretzel-like”shape in mice(Figure 1),whereas human NMJs have a smaller,fragmented structure throughout *** NMJs exhibit smaller or fragmented endplates,partial denervation,reduced numbers of synaptic vesicles,abnormal presynaptic mitochondria,and dysfunctional perisynaptic Schwann cells(Alhindi et al.,2022).

关键词： aging structure Figure