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Baran N.,Polytechnic University of Bucharest | Detzortzis A.,Polytechnic University of Bucharest | Hawas M.N.,Foundation of Technical Education | Besnea D.,Polytechnic University of Bucharest
Romanian Review Precision Mechanics, Optics and Mechatronics | Year: 2014

In this paper, for a rotating machine with two profiled rotors, the influence of the rotor shape on the volumetric flow rate and on the driving power of the machine is showed. If the radius and the rotor length are considered constant, the rotating piston shape influences the flow rate circulated by the machine. The rotor shape in two versions is presented; for each constructive version the power lost by viscous friction between the rotors and the case is calculated. © 2014, Editura Cefin. All right reserved. Source

Mohammed A.A.,University of Technology, Iraq | Hussein A.A.,Foundation of Technical Education
International Journal of Mechanical and Mechatronics Engineering | Year: 2015

The enhancements of heat transfer characteristics in a vertical and horizontal uniformly heated circular tube fitted with conical nozzles of constant diameter ratio (d/D=0.538) and swirl generator for air flow with Reynolds number range of 5000-23000 are experimentally investigated. Three twisted-tapes of different twist ratios, Y=2, 3, and 6, are introduced in each run. The results show that the heat transfer process enhances as the tube position changes from vertical to horizontal. It is found that each application of the conical nozzle and the twisted tape can help to increase considerably the heat transfer rate over that of the plain tube by about 270% and 195%, respectively for vertical position and by about 280% and 207%, respectively for horizontal position. Empirical equations for Nusselt number, friction factor and performance analysis criteria for both positions to assess the real benefits in using the turbulators and swirl generator of the tube are developed. © December 2015 IJENS. Source

Al-Saady D.M.,Foundation of Technical Education
ICOS 2010 - 2010 IEEE Conference on Open Systems | Year: 2010

Genetic algorithms (GAs) are a class of optimization algorithms. GAs attempt to solve problems through modeling a simplified version of genetic processes. There are many problems for which a Genetic Algorithm approach is useful. It is, however, undetermined if cryptanalysis is such a problem. Therefore, this work trying to explore the use of Genetic Algorithms in cryptography. The focus is to be on substitution cipher. The principles used in this cipher form the foundation for many of the modern cryptosystems. The frequency analysis is used as an essential factor in objective function. © 2010 IEEE. © 2010 IEEE. Source

Hussein A.A.,Foundation of Technical Education
International Journal of Mechanical and Mechatronics Engineering | Year: 2013

Numerical investigation have been performed systematically to study the mixed convection heat transfer and air flow patterns in the simultaneously fully developed region of inclined annulus with constant heat flux for inner cylinder and adiabatic outer cylinder. The time dependent partial differential equations representing the vorticity, the stream function and the temperature were approximated by finite difference equations and solved on the computer. The values of Rayliegh number (Ra) are varied from 103 to 106 and the value of radius ratio is 0.5. The results show that the transition from single-eddy pattern to the double-eddy pattern appears to occur at Ra between 105 and 106. Large temperature gradients and higher local Nusselt number attain at the bottom except at vertical position in which the angular variation of the Nusselt number remains constant because of symmetry about vertical axis. © February 2013 IJENS. Source

Al-Naima F.M.,Nahrain University | Ali R.S.,University of Basrah | Abid A.J.,Foundation of Technical Education
International Journal of Information Technology and Web Engineering | Year: 2014

This article presents the design of a reliable, accurate, and easy to install solar dual axis tracking system. The system utilizes the GPS for fixing the time, date and location in terms of longitude and latitude. Approximations having high accuracy of the astronomical equations to represent the declination angle and the equation of time are selected to determine the sun locations needed by the designed tracking system in any chosen location on earth. The proposed system is standalone, accurate, durable, reliable, and cost efficient. Annual energy assessments of the system are also given. Copyright © 2014, IGI Global. Source

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