الوسم: VR Post graduation
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كلية التكنولوجيا: منشور علمي للطالب دكتوراه الطور الثالث مريزقي الطاهر – قسم الالكترونيك
عنوان المقال
Effect of magnetic iron(III) oxide particle addition with MWCNTs in kenaf fibre-reinforced epoxy composite shielding material in ‘E’, ‘F’, ‘I’ and ‘J’ band microwave frequencies
اسم المجلة
Materials Research Express
سنة الاصدار
2019
الملخص
Mechanically toughened electromagnetic shielding composite material was prepared with MWCNTs and Iron(III) oxide nano particles. The principal aim of this research work is explicating the advantage of magnetic particle addition along with conductive MWCNTs in EMW shielding. The kenaf fibre, MWCNTs and Iron(III) oxide particles were surface-treated by APTMS for effective dispersion and adhesion on matrix medium. The EM wave shielding composites were prepared using hand layup method. The mechanical results shows addition of kenaf fibre increased the tensile, flexural and impact properties. Similarly additions of MWCNTs and iron(III) oxide particles increased the electrical permittivity and magnetic permeability of epoxy matrix. The hysteresis graphs showed improved magnetization and retentivity in epoxy composites. The maximum EM wave shielding effectiveness of 82.5% (14.5 dB) was observed for composite designation ‘E’ in J band microwave frequency. The SEM images showed improved adhesion of fibre and dispersion of particle in epoxy matrix.
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كلية التكنولوجيا : منشور علمي للطالب دكتوراه الطور الثالث -رحماني بلقاسم -قسم الالكترونيك
ABSTRACT
In this paper, a novel approach for adaptive control of flexible multi-link robots in the joint space is pre-sented. The approach is valid for a class of highly uncertain systems with arbitrary but bounded dimen-sion. The problem of trajectory tracking is solved through developing a stable inversion for robot dynamics using only joint angles measurement; then a linear dynamic compensator is utilised to stabilise the tracking error for the nominal system. Furthermore, a high gain observer is designed to provide an estimate for error dynamics. A linear in parameter neural network based adaptive signal is used to approximate and eliminate the effect of uncertainties due to link flexibilities and vibration modes on tracking performance, where the adaptation rule for the neural network weights is derived based on Lyapunov function. The stability and the ultimate boundedness of the error signals and closed-loop system is demonstrated through the Lyapunov stability theory. Computer simulations of the proposed robust controller are carried to validate on a two-link flexible planar manipulator.
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َ Zeghoudi Abdelfatah , Contribution to minimizing the cosine loss in a thermodynamic solar tower power plant by a change in the target position, European Journal of Electrical Engineering
Abstract :
In solar power tower plant, the amount of energy exploited of direct solar radiation depends to the angle between the solar rays and the heliostat position in the solar field. The maximum incident solar radiation on the heliostat be when the sunrays are perpendicular to the heliostat reflection area. That cannot exist in full sunny day for reason of cosine loss effect due by the variation of the sun position, which affected the efficiency of a heliostat. This paper shows new approach of installing the mobile target of sunrays receiver to minimize the cosine losses of the heliostat field in the solar power tower plant for increasing his efficiency. The simulation results validated the advantage of uses the mobile target in the central solar tower. In addition, it illustrates the possibility of eliminating the cosine losses based on changing the target position.
