Rahaman M.,Indian Institute of Technology Kharagpur |
Thomas S.P.,King Fahd University of Petroleum and Minerals |
Thomas S.P.,Yanbu Industrial College |
Hussein I.A.,King Fahd University of Petroleum and Minerals |
De S.K.,King Fahd University of Petroleum and Minerals
Polymer Composites | Year: 2013
Low density polyethylene nanocomposites filled with carbon nanotubes (CNT) having three different aspect ratios have been prepared by melt mixing technique. The effects of CNT loading, its aspect ratio, and frequency of electric field on electrical and dielectric properties of the nanocomposites have been investigated. DC and AC electrical resistivity are found to decrease with the increase in CNT loading in the composites, while the dielectric constant and loss increase with the increase in CNT loading in the composites. AC electrical resistivity, dielectric constant, and dielectric loss decrease with the increase in frequency. Furthermore, the electrical resistivity decreases with the increase in aspect ratio of CNT, whereas the dielectric constant and loss increase with the increase in aspect ratio of CNT. While probable mechanisms for electrical conduction have been proposed, dielectric results have been explained by considering CNT as nanocapacitors. © 2013 Society of Plastics Engineers.
Soliman H.M.,Cairo University |
Dabroum A.,Yanbu Industrial College |
Mahmoud M.S.,King Fahd University of Petroleum and Minerals |
Soliman M.,Cairo University |
Soliman M.,University of Calgary
Journal of the Franklin Institute | Year: 2011
This paper deals with the simultaneous coordinated design of power system stabilizer (PSS) and the flexible ac transmission systems (FACTS) controller. The problem of guaranteed cost reliable control with regional pole constraint against actuator failures is investigated. The state feedback controllers are designed to guarantee the closed loop system satisfying the desired pole region, thus achieving satisfactory oscillation damping and settling time, and having the guaranteed cost performance simultaneously. The proposed controllers satisfy desired dynamic characteristics even in faults cases. The controllers parameters are obtained using the linear matrix inequalities (LMI) optimization. Simulation results validate the effectiveness of this approach. © 2011 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.
Qureshi M.I.,Jamia Millia Islamia University |
Rafat M.,Jamia Millia Islamia University |
Azad S.I.,Yanbu Industrial College
European Journal of Physics | Year: 2010
The motion of a simple pendulum of arbitrary amplitude is usually treated by approximate methods. By using generalized hypergeometric functions, it is however possible to solve the problem exactly. In this paper, we provide the exact equation of motion of a simple pendulum of arbitrary amplitude. A new and exact expression for the time of swinging of a simple pendulum from the vertical position to an arbitrary angular position θ is given by equation (3.10). The time period of such a pendulum is also exactly expressible in terms of hypergeometric functions. The exact expressions thus obtained are used to plot the graphs that compare the exact time period T (θ0) with the time period T (0) (based on simple harmonic approximation). We also compare the relative difference between T (0) and T (θ0) found from the exact equation of motion with the usual perturbation theory estimate. The treatment is intended for graduate students, who have acquired some familiarity with the hypergeometric functions. This approach may also be profitably used by specialists who encounter during their investigations nonlinear differential equations similar in form to the pendulum equation. Such nonlinear differential equations could arise in diverse fields, such as acoustic vibrations, oscillations in small molecules, turbulence and electronic filters, among others. © 2010 IOP Publishing Ltd.
Azab M.,Yanbu Industrial College
IEEE International Symposium on Industrial Electronics | Year: 2010
A particle swarm optimization (PSO) technique is used to identify the optimal power point of a photovoltaic module used in a stand-alone PV system as a battery charger. The PSO algorithm searches the maximum power point of the PV module by determining the array voltage at maximum point (VMPP). The tracked variable is used as a reference value (set point) to an ON/OFF controller with a tolerance band which controls the operation of a dc boost chopper such that the PV module is forced to operate at the optimal power point. According to the obtained results of the proposed system, the tracking efficiency is not less than 98 % with a convergence time of 14 ms. Compared with the well known Perturb and Observe tracking method, the proposed system is accurate and reliable. © 2010 IEEE.
Arunagiri A.,Yanbu Industrial College |
Venkatesh B.,Ryerson University
Journal of Engineering Science and Technology | Year: 2011
Radial distribution systems (RDS) require special load flow methods to solve power flow equations owing to their high R/X ratio. Increasing use of power electronic devices and effect of magnetic saturation cause harmonics in RDS. This paper proposes a novel algorithm to compute the power flow solution of a RDS accounting for all the harmonic components. It uses a recursive solution technique. The proposed method uses a novel dynamic data structure reported in the paper. The proposed method is tested upon a 33-bus RDS and the results are reported. © School of Engineering, Taylor's University.