Bangladesh American International University
Dhaka, Bangladesh
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Hasan S.,Bangladesh American International University
Advanced Studies in Theoretical Physics | Year: 2016

When polymer melts flow near a corrugated boundary, individual chains go through oscillatory shear due to the perturbed velocity field produced by corrugation. In order to obtain friction constant for this surface, we find total dissipation using the oscillatory strain rate of individual chains. For small slip velocities this friction constant approaches the constant obtained by macroscopic hydrodynamics. (P. G. De Gennes, C. R. Acad. Sci. Paris Ser. B, 289:220, 1979). Large slip velocities mean smaller time period of shear oscillation, so less dissipation and we observe shear thinning. © 2016 Sayed Hasan.

Al Iqbal R.,Bangladesh American International University
2012 International Conference on Informatics, Electronics and Vision, ICIEV 2012 | Year: 2012

Rural areas of Bangladesh do not have quality healthcare facilities or doctors. However, Internet is widely available everywhere in the country. A web based Clinical Decision Support System (CDSS) is proposed that will serve the rural medical centers. A Clinical Decision Support System is a software that provides diagnostic suggestions based on input patient data. The system will use Artificial Intelligence technology to use given expert knowledge. The two popular types of decision support system are described, Knowledge-based and Data mining based system. Both have their respective strengths and weaknesses. A hybrid algorithm is proposed that combines the two approaches and attains higher performance. The hybrid algorithm FOCL is highly suitable for decision support. A modified form of FOCL is presented that can also take diagnostic cost into account. Several real world experiments show the advantage of this new hybrid system. © 2012 IEEE.

Uddin M.J.,Universiti Sains Malaysia | Uddin M.J.,Bangladesh American International University | Khan W.A.,National University of Sciences and Technology | Ismail A.I.,Universiti Sains Malaysia
PLoS ONE | Year: 2012

Steady two dimensional MHD laminar free convective boundary layer flows of an electrically conducting Newtonian nanofluid over a solid stationary vertical plate in a quiescent fluid taking into account the Newtonian heating boundary condition is investigated numerically. A magnetic field can be used to control the motion of an electrically conducting fluid in micro/nano scale systems used for transportation of fluid. The transport equations along with the boundary conditions are first converted into dimensionless form and then using linear group of transformations, the similarity governing equations are developed. The transformed equations are solved numerically using the Runge-Kutta-Fehlberg fourth-fifth order method with shooting technique. The effects of different controlling parameters, namely, Lewis number, Prandtl number, buoyancy ratio, thermophoresis, Brownian motion, magnetic field and Newtonian heating on the flow and heat transfer are investigated. The numerical results for the dimensionless axial velocity, temperature and nanoparticle volume fraction as well as the reduced Nusselt and Sherwood number have been presented graphically and discussed. It is found that the rate of heat and mass transfer increase as Newtonian heating parameter increases. The dimensionless velocity and temperature distributions increase with the increase of Newtonian heating parameter. The results of the reduced heat transfer rate is compared for convective heating boundary condition and found an excellent agreement. © 2012 Uddin et al.

Iqbal Md.R.A.,Bangladesh American International University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

Ensemble methods have become very well known for being powerful pattern recognition algorithms capable of achieving high accuracy. However, Ensemble methods produces learners that are not comprehensible or transferable thus making them unsuitable for tasks that require a rational justification for making a decision. Rule Extraction methods can resolve this limitation by extracting comprehensible rules from a trained ensembles of classifiers. In this paper, we present an algorithm called REEMTIC that uses a symbolic learning algorithm (Decision Tree) on each underlying classifier of the ensemble and combines them. Experiments and theoretical analysis show REEMTIC generates highly accurate rules that closely approximates the Ensemble Learned Model. © 2012 Springer-Verlag.

Uddin Md.J.,Bangladesh American International University | Beg O.A.,Propulsion Research | Ismail A.I.,Universiti Sains Malaysia
Journal of Thermophysics and Heat Transfer | Year: 2015

Steady two-dimensional laminar mixed convective boundary-layer slip nanofluid flow in a Darcian porous medium due to a stretching/shrinking sheet is studied theoretically and numerically.Athermal radiative effect is incorporated in the model. The governing transport, partial differential equations, along with the boundary conditions, are transformed into a dimensionless form and then, via a linear group of transformation, a system of coupled similarity differential equations is derived. The transformed equations are solved numerically using the Runge-Kutta-Fehlberg fourth-fifth-order numerical quadrature method from Maple symbolic software. The effects of the controlling parameters (namely, stretching/shrinking, velocity slip, thermal slip, mass slip, Darcy number, radiation conduction, buoyancy ratio parameter, and Lewis number) on the dimensionless velocity, temperature, nanoparticle volume fraction, velocity gradient, temperature gradient, and nanoparticle volume fraction gradient are shown in graphical form and interpreted in detail. Comparisons with published works are carried out and are found to be in excellent agreement. The current study is relevant to high-temperature nanomaterials processing operations. Copyright © 2014 by the American Institute of Aeronautics and Astronautics, Inc.

Iqbal R.A.,Bangladesh American International University
Proceedings - 2011 International Conference on Multimedia and Signal Processing, CMSP 2011 | Year: 2011

Standard hybrid learners that use domainknowledge require stronger knowledge that is hard andexpensive to acquire. However, weaker domainknowledge can benefit from prior knowledge while beingcost effective. Weak knowledge in the form of featurerelative importance (FRI) is presented and explained.Feature relative importance is a real valuedapproximation of a feature's importance provided byexperts. Advantage of using this knowledge isdemonstrated by IANN, a modified multilayer neuralnetwork algorithm. IANN is a very simple modification ofstandard neural network algorithm but attains significantperformance gains. Experimental results in the field ofmolecular biology show higher performance over otherempirical learning algorithms including standardbackpropagation and support vector machines. IANNperformance is even comparable to a theory refinementsystem KBANN that uses stronger domain knowledge. © 2011 IEEE.

A local similarity solution of unsteady MHD natural convection heat and mass transfer boundary layer flow past a flat porous plate within the presence of thermal radiation is investigated. The effects of exothermic and endothermic chemical reactions with Arrhenius activation energy on the velocity, temperature, and concentration are also studied in this paper. The governing partial differential equations are reduced to ordinary differential equations by introducing locally similarity transformation (Maleque (2010)). Numerical solutions to the reduced nonlinear similarity equations are then obtained by adopting Runge-Kutta and shooting methods using the Nachtsheim-Swigert iteration technique. The results of the numerical solution are obtained for both steady and unsteady cases then presented graphically in the form of velocity, temperature, and concentration profiles. Comparison has been made for steady flow (A = 0) and shows excellent agreement with Bestman (1990), hence encouragement for the use of the present computations. © 2013 Kh. Abdul Maleque.

Maleque K.A.,Bangladesh American International University
Chemical Engineering Communications | Year: 2010

The present study investigates the effects of mixed temperature- and depth-dependent viscosity and Hall current on an unsteady flow of an incompressible electrically conducting fluid on a rotating disk in the presence of a uniform magnetic field. We assume that the fluid viscosity strongly depends on temperature and depth, which may be directly applicable to the earth's mantle and a uniform mid-ocean ridge basalt reservoir in whole mantle flow. The system of axial symmetric nonlinear partial differential equations governing the unsteady flow and heat transfer is written in cylindrical polar coordinates and reduced to nonlinear ordinary differential equations by introducing suitable similarity parameters. Solutions for the flow and temperature fields are obtained numerically assuming large Prandtl number by using Runge-Kutta and shooting methods. The nature of radial, tangential, and axial velocities and temperature in the presence of a uniform magnetic field is presented for changing various nondimensional parameters at different layers of the medium. The coefficients of skin frictions and the rate of heat transfer are calculated at different parameters. Comparison has been made for steady flow (C=0) and shows excellent agreement with Sparrow and Gregg (1959), hence encouragement for the use of the present numerical computations. © Taylor & Francis Group, LLC.

Uddin M.J.,Bangladesh American International University | Khan W.A.,National University of Sciences and Technology | Amin N.S.,University of Technology Malaysia
PLoS ONE | Year: 2014

The unsteady two-dimensional laminar g-Jitter mixed convective boundary layer flow of Cu-water and Al2O3-water nanofluids past a permeable stretching sheet in a Darcian porous is studied by using an implicit finite difference numerical method with quasi-linearization technique. It is assumed that the plate is subjected to velocity and thermal slip boundary conditions. We have considered temperature dependent viscosity. The governing boundary layer equations are converted into non-similar equations using suitable transformations, before being solved numerically. The transport equations have been shown to be controlled by a number of parameters including viscosity parameter, Darcy number, nanoparticle volume fraction, Prandtl number, velocity slip, thermal slip, suction/injection and mixed convection parameters. The dimensionless velocity and temperature profiles as well as friction factor and heat transfer rates are presented graphically and discussed. It is found that the velocity reduces with velocity slip parameter for both nanofluids for fluid with both constant and variable properties. It is further found that the skin friction decreases with both Darcy number and momentum slip parameter while it increases with viscosity variation parameter. The surface temperature increases as the dimensionless time increases for both nanofluids. Nusselt numbers increase with mixed convection parameter and Darcy numbers and decreases with the momentum slip. Excellent agreement is found between the numerical results of the present paper with published results. © 2014 Uddin et al.

Islam S.M.,Bangladesh American International University
International Journal of Energy and Environmental Engineering | Year: 2012

Ramea is a small island in southern Newfoundland. Since 2004, it has a wind-diesel hybrid power system to provide power for approximately 600 inhabitants. In this paper, wind speed data, load data, and sizing of pumped hydro system at Ramea, Newfoundland are presented. The dynamic model of wind turbine, pumped hydro system, and diesel generator are included in this paper. The dynamic model is simulated in SIMULINK/MATLAB to determine the system voltage and frequency variation and also to visualize different power outputs. Sizing of pumped hydro system indicates that a 150-kW pumped hydro storage system can be installed in Ramea to increase the renewable energy fraction to 37% which will reduce non-renewable fuel consumption on this island. Also, it is found that a pumped hydro energy storage system for Ramea is a much better choice than a hydrogen energy storage system. Such a system will have a higher overall efficiency and could be maintained using local technical expertise, therefore, a more appropriate technology for Ramea. © 2012 Islam; licensee Springer.

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