Zainal Abdul Aziz

Abstract: The investigation is made to study the combined effects of thermal radiation, viscous dissipation and Joule heating in steady two-dimensional electrical magnetohydrodynamic boundary layer flow of nanofluids using Buongiorno's model over a permeable linear stretching sheet. The system of transport equation incorporate the effects of Brownian motion, thermophoresis, thermal and concentration stratifications in the presence of nano energy conversion emerging parameters. A similarity transformation is implemented to reduce the boundary layer flow equations to a system of nonlinear ordinary differential equations, then solved by implicit finite difference scheme. The computation has been investigated for certain range of values required emerging parameters M(0 ≤ M ≤ 2.5), E1(0 ≤ E1 ≤ 1.0), s(−0.4≤s≤1.0), λ(0.1 ≤ λ ≤ 2.0), N(0.1 ≤ N ≤ 1.0), Rd(0 ≤ Rd ≤ 1.0), Nb(0.1 ≤ Nb ≤ 0.5), Nt(0.1 ≤ Nt ≤ 0.5), Ec(0 ≤ Ec ≤ 0.8), st(0 ≤ st ≤ 0.7), Le(2 ≤ Le ≤ 10), sc(0 ≤ sc ≤ 0.7). Velocity field enhances with the electric field and mixed convection but decreases with fluid suction. Electric field resolved the sticking effects due to the magnetic field. Thermal and concentration stratifications lead to a reduction in temperature and nanoparticle concentration. Heat conduction is sensitive to an increase in an electric field, thermal radiation and viscous dissipation. The rate of heat and mass transfer reduces by increasing thermophoresis and thermal stratifications and it increases for larger values of suction. Numerical values are obtained for the skin friction, local Nusselt and Sherwood number for different involving parameters tabulated and examined. We compare the present numerical solution in limiting sense with previously published investigation presented and examined reveals good agreement.

Abstract: The unsteady mixed convection flow of electrical conducting nanofluid and heat transfer due to a permeable linear stretching sheet with the combined effects of an electric field, magnetic field, thermal radiation, viscous dissipation, and chemical reaction have been investigated. A similarity transformation is used to transform the constitutive equations into a system of nonlinear ordinary differential equations. The resultant system of equations is then solved numerically using implicit finite difference method. The velocity, temperature, concentration, entropy generation, and Bejan number are obtained with the dependence of different emerging parameters examined. It is noticed that the velocity is more sensible with high values of electric field and diminished with a magnetic field. The radiative heat transfer and viscous dissipation enhance the heat conduction in the system. Moreover, the impact of mixed convection parameter and Buoyancy ratio parameter on Bejan number profile has reverse effects. A chemical reaction reduced the nanoparticle concentration for higher values.

Abstract: The present paper addresses magnetohydrodynamics (MHD) flow of nanofluid towards nonlinear stretched surface with variable thickness in the presence of electric field. The analysis is presented with viscous dissipation, Joule heating, and chemical reaction. Characteristics of heat transfer are analyzed with the electric field and variable thickness phenomenon. The partial differential equations are converted into dimensionless ordinary differential equations by employing suitable transformations. Implicit finite difference scheme is implemented to solve the governing dimensionless problems. Behaviors of several sundry variables on the flow and heat transfer are scrutinized. Skin friction coefficient, the local Nusselt number local Sherwood number are presented and evaluated. It is observed that the skin friction, the rate of heat and mass transfer reduces with a rise in wall thickness. Electric field enhances the nanofluid velocity and temperature but reduced the concentration. Thermal radiation is sensitive to an increase in the nanofluid temperature and thicker thermal boundary layer thickness. Obtained results are also compared with the available data in the limiting case and good agreement is noted.

Abstract: Challenges in many real-world optimization problems arise from limited hardware availability, particularly when the optimization must be performed on a device whose hardware is highly restricted due to cost or space. This paper proposes a new algorithm, namely Enhanced compact Artificial Bee Colony (EcABC) to address this class of optimization problems. The algorithm benefits from the search logic of the Artificial Bee Colony (ABC) algorithm, and similar to other compact algorithms, it does not store the actual population of tentative solutions. Instead, EcABC employs a novel probabilistic representation of the population that is introduced in this paper. The proposed algorithm has been tested on a set of benchmark functions from the CEC2013 benchmark suite, and compared against a number of algorithms including modern compact algorithms, recent population-based ABC variants and some advanced meta-heuristics. Numerical results demonstrate that EcABC significantly outperforms other state of the art compact algorithms. In addition, simulations also indicate that the proposed algorithm shows a comparative performance when compared against its population-based versions.

Abstract: The combined effects of thermal stratification, applied electric and magnetic fields, thermal radiation, viscous dissipation and Joules heating are numerically studied on a boundary layer flow of electrical conducting nanofluid over a nonlinearly stretching sheet with variable thickness. The governing equations which are partial differential equations are converted to a couple of ordinary differential equations with suitable similarity transformation techniques and are solved using implicit finite difference scheme. The electrical conducting nanofluid particle fraction on the boundary is passively rather than actively controlled. The effects of the emerging parameters on the electrical conducting nanofluid velocity, temperature, and nanoparticles concentration volume fraction with skin friction, heat transfer characteristics are examined with the aids of graphs and tabular form. It is observed that the variable thickness enhances the fluid velocity, temperature, and nanoparticle concentration volume fraction. The heat and mass transfer rate at the surface increases with thermal stratification resulting to a reduction in the fluid temperature. Electric field enhances the nanofluid velocity which resolved the sticking effects caused by a magnetic field which suppressed the profiles. Radiative heat transfer and viscous dissipation are sensitive to an increase in the fluid temperature and thicker thermal boundary layer thickness. Comparison with published results is examined and presented.

Abstract: Stochastic optimization problems arise in decision-making problems under uncertainty, and find various applications in economics and finance. On the other hand, problems in finance have recently led to new developments in the theory of stochastic control. This volume provides a systematic treatment of stochastic optimization problems applied to finance by presenting the different existing methods: dynamic programming, viscosity solutions, backward stochastic differential equations, and martingale duality methods. The theory is discussed in the context of recent developments in this field, with complete and detailed proofs, and is illustrated by means of concrete examples from the world of finance: portfolio allocation, option hedging, real options, optimal investment, etc. This book is directed towards graduate students and researchers in mathematical finance, and will also benefit applied mathematicians interested in financial applications and practitioners wishing to know more about the use of stochastic optimization methods in finance.

Abstract: Thank you for reading physical and computational aspects of convective heat transfer. Maybe you have knowledge that, people have search hundreds times for their chosen readings like this physical and computational aspects of convective heat transfer, but end up in malicious downloads. Rather than reading a good book with a cup of tea in the afternoon, instead they are facing with some harmful virus inside their computer.

Abstract: The motivation of the current article is to explore the energy activation in MHD radiative Couette-Poiseuille flow nanofluid in horizontal channel with convective boundary conditions. The mathematical model of Buongiorno [1] effectively describes the current flow analysis. Additionally, the impact of chemical reaction is also taken in account. The governing flow equations are simplified with the help of boundary layer approximations. Non-linear coupled equations for momentum, energy and mass transfer are tackled with analytical (HAM) technique. The influence of dimensionless convergence parameter like Brownian motion parameter, radiation parameter, buoyancy ratio parameter, dimensionless activation energy, thermophoresis parameter, temperature difference parameter, dimensionless reaction rate, Schmidt number, Brinkman number, Biot number and convection diffusion parameter on velocity, temperature and concentration profiles are discussed graphically and in tabular form. From the results, it is elaborate that the nanoparticle concentration is directly proportional to the chemical reaction with activation energy and the performance of Brownian motion on nanoparticle concentration gives reverse pattern to that of thermophoresis parameter.

Abstract: The effects of a heat sink and the source size and location on the entropy generation, MHD natural convection flow and heat transfer in an inclined porous enclosure filled with a Cu-water nanofluid are investigated numerically. A uniform heat source is located in a part of the bottom wall, and a part of the upper wall of the enclosure is maintained at a cooled temperature, while the remaining parts of these two walls are thermally insulated. Both the left and right walls of the enclosure are considered to be adiabatic. The thermal conductivity and the dynamic viscosity of the nanofluid are represented by different verified experimental correlations that are suitable for each type of nanoparticle. The finite difference methodology is used to solve the dimensionless partial differential equations governing the problem. A comparison with previously published works is performed, and the results show a very good agreement. The results indicate that the Nusselt number decreases via increasing the nanofluid volume fraction as well as the Hartmann number. The best location and size of the heat sink and the heat source considering the thermal performance criteria and magnetic effects are found to be D = 0.7 and B = 0.2. The entropy generation, thermal performance criteria and the natural heat transfer of the nanofluid for different sizes and locations of the heat sink and source and for various volume fractions of nanoparticles are also investigated and discussed.