Wyniki wyszukiwania - BazTech

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Unsteady hydromagnetic flow of Oldroyd-B fluid over an oscillatory stretching surface: a mathematical model

Khan S. U., Ali N.

Technical Sciences / University of Warmia and Mazury in Olsztyn

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2017

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nr 20(1)

87--100

EN

In the present work, we have studied an unsteady, two-dimensional boundary layer flow of a magnetohydrodynamics (MHD) Oldroyd-B fluid over an oscillatory stretching surface. The problem is modeled by using constitutive equations. The number of independent variables in the governing equations are reduced by using appropriate dimensionless variables. The analytical solution is computed by using homotopy analysis method. The influences of various physical parameters such as Deborah numbers, ratio of angular frequency to stretching rate parameter and Hartmann number on time-series of velocity and transverse velocity profiles at different time instants are investigated and discussed quantitatively with the help of various graphs. It is observed that amplitude of velocity increases by increasing ratio of oscillating frequency to stretching rate parameter while decreases by increasing Hartmann number. It is further observed that the magnitude of velocity decreases by increasing Hartmann number and Deborah numbers in the terms of relaxation time parameter.

2

Some fixed point results on G-metric and Gb-metric spaces

Jaradat M. M. M., Mustafa Z., Khan S. U., Arshad M., Ahmad J.

Demonstratio Mathematica

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2017

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Vol. 50, nr 1

190--207

EN

The purpose of this paper is to prove some fixed point results using JS-G-contraction on G-metric spaces, also to prove some fixed point results on Gb-complete metric space for a new contraction. Our results extend and improve some results in the literature. Moreover, some examples are presented to illustrate the validity of our results.

3

Influence of sintering temperature on secondary phases formation and microwave dielectric properties of Ca2Ce2Ti5O16 ceramics

Manan A., Khan S. U., Qazi I

Materials Science Poland

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2014

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Vol. 32, No. 2

297--300

EN

Ca2Ce2Ti5O16 dielectric ceramics prepared by conventional solid-state ceramic route was investigated. Phase composition and microwave dielectric properties were measured using XRD and Vector network analyzer, respectively. XRD analysis of the calcined and sintered samples revealed the formation of CeO2 and another unidentified phase (that vanished at > 1400 °C) as secondary phases along with the parent Ca2Ce2Ti5O16 phase. The amount of the parent Ca2Ce2Ti5O16 phase increased with increasing sintering temperature from 1350 °C to 1450 °C accompanied by a decrease in the apparent density. The density decreased but er and Qu fo increased with sintering temperature. An er ~ 81.5, Qu fo ~ 5915 GHz and t f ~ 219 GHz were achieved for the sample sintered at 1450 °C.

4

Secure-Sim-G: Security-Aware Grid Simulator - Basic Concept and Structure

Gębczyński G., Kołodziej J., Khan S. U.

Journal of Telecommunications and Information Technology

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2012

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nr 1

33-42

EN

Task scheduling and resource allocation are the key issues for computational grids. Distributed resources usually work at different autonomous domains with their own access and security policies that impact successful job executions across the domain boundaries. In this paper we present a security-aware grid simulator Secure-Sim-G, which facilitates the evaluation of the different scheduling heuristics under various scheduling criteria in several grid scenarios defined by the security conditions, grid size and system dynamics. The simulator allows the flexible activation or inactivation of all of the scheduling criteria and modules, which makes the application well adapted to the proper illustration of the different realistic scenarios and avoids the possible restriction to the specific scheduling resolution methods. The simulation results and traces may be graphically represented and stored at the server and can retrieved in different formats such as spreadsheets or pdf files.