Faculté du Génie Electrique et d'Informatique

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Behavior of Low Density polyethylene Aged Under UV Radiation.
(26/08/2019) Slimani, Ferhat; Hedir, Abdallah; Moudoud, Mustapha; Loucif, Amina
Low density polyethylene (LDPE) is a usual material used within high voltage insulation systems. Like all polymers, this material may be aged after working under high voltage for a long time. The ageing process of this ma-terial is essentially caused by external factors. The exhibition to ultraviolet (UV) radiation is one of these factors. This work investigates the effect of this constraint on the electrical and mechanical properties of LDPE after UV-ageing. This paper includes the sample preparation process, the ageing of sam-ples under identical conditions for up 380 h and finally the analysis of electrical and mechanical properties after the ageing process. The obtained results show that these properties are considerably affected by the ultraviolet radiation
Enhanced light absorption in porous silicon with nanocrystalline TiO2 deposited by metal-organic chemical vapor deposition (MOCVD)
(26/06/2019) Hocine, Dalila; S. Oussidhoum; M. Bensidhoum; A. Crisbasan; D. Chaumont; E. Bourennane; A. Moussi; E. Lesniewska; N. Geoffroy; M.S. Belkaid
In this paper, nanocrystalline TiO2 thin films were successfully deposited on porous silicon (PSi) by metal organic chemical vapor deposition (MOCVD) technique for different periods of times: 5, 10 and 15 min. The objective was to improve the optical absorption properties of the porous layers dedicated for photovoltaic application. The structural, morphological and optical properties of the elaborated TiO2/PSi samples were analyzed by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), photoluminescence (PL) and UV-Visible absorption spectroscopy methods. The effect of deposition time on the microstructural properties which influence the optical characteristics of the obtained samples was also examined. The XRD analysis confirms the nanocrystalline structure of the deposited TiO2 composed only by anatase. The SEM characterization evidenced an increase in the TiO2 film thickness showing more uniform surfaces as the deposition time rises. Correspondingly, the surface roughness increases with the particle size and film thickness as indicated by AFM studies. The UV-Vis measurements showed a considerable enhancement in optical absorption of porous silicon after the deposition of nanocrystalline TiO2 films. Indeed, the TiO2 coatings deposited on PSi for 15 min with thickness of 200 nm have the best structure quality and exhibit, consequently, the highest absorption. From these interesting results, we demonstrate the viability of the use of the MOCVD as reproducible process for the elaboration of highly efficient antireflective layers.
Impact of Thermal Constraint on The Low Density Polyethylene (LDPE) Properties
(26/08/2019) Hedir, Abdallah; Slimani, Ferhat; Moudoud, Mustapha; Bellabas, Ferhat; Loucif, Amina
Nowadays, Low density polyethylene (LDPE) is increasingly used as voltage cable insulating material. Owing to its excellent mechanical and electri-cal properties, LDPE may undergo degradation under service conditions. The focus of this work is to investigate the eventual impact of temperature on the LDPE characteristics. For this purpose, dielectric properties (Breakdown strength, Dielectric loss factor and dielectric constant); and mechanical charac-teristics (tensile strength and elongation at break) were studied. Aim of this work is the investigation of possible changes in some Low density polyethylene (LDPE) properties subjected to thermal constraint. The obtained results show that all the properties are widely affected by thermal constraint.
Investigation on High Switching Performances Graphene Transistors Using Band-gap Engineering
(17/07/2019) Benfdila, Arezki; Lakhlef, Ahcene
Graphene transistors are considered to be the successor’s basic element for the next generation of advanced integrated circuits. The graphene suffers from the absence of energy band gap to experience a semiconductor like characteristics. In order to instigate a bandgap, several techniques are used to beak symmetry. The most useful graphene sheet is the Graphene Nanoribbon (GNR). The present paper deals with the investigation on the bandgap engineering approach aiming an increase of the switching characteristics of the graphene transistors. The GNR sheets are synthesized using different techniques yielding controlled electronics and physical characteristics
Neuro-fuzzy Control of a Position-Position Teleoperation System Using FPGA
(26/08/2019) Khati, Hocine; Mellah, Rabah; Talem, Hand
This paper presents an ANFIS (adaptive neurofuzzy inference system) controller for a teleoperation system using FPGA (Field Programmable Gate Array). The proposed controller allows adapting to the dynamic variations of the master and slave models by adjusting the output parameters of the neuro-fuzzy network using a learning algorithm, while taking advantage of the benefits of the FPGA computing power and its high sampling frequency. The ANFIS controllers are developed in MATLAB-Simulink environment and implemented using Simulink's Fixed point tool and HDL Coder. These features provide a fast and accurate control algorithm while optimizing the hardware resources used by the FPGA. The proposed controllers are implemented on a teleoperation system with one degree of freedom. The experimental position tracking results clearly show that the proposed control algorithm guarantees better performance compared to conventional control methods (PID).
Stochastic evaluation of defects in eddy currents non-destructive testing system
(29/08/2019) OUDNI, Zehor; MOHELLEBI, Hassane
In this paper, we discuss the defect evaluation in a conductive material, by a method based on stochastic finite elements. This later allows then to obtain a hazard distribution of one or more physical properties of the material. To do this, we have considered two kinds of distributions of random variables; Gaussian and Lognormal ones. Those variables will represent the distribution of the electrical conductivity in the area of the defect to be investigated and an evaluation of the impact on the reliability of the device will be done. A stochastic finite element calculation code is developed and the variation of the impedance is then deduced by doing a scan along the surface of the conductive plate. The computational was performed in the two cases successively, Gaussian and Lognormal distributions. A post-treatment is performed by the calculation of the reliability index. This results Allowed us to evaluate the probability of failure associated with the nature of the fault present on the conductive plate for both cases of random variables. The study is completed by the evaluation of the impact of the defect thickness on the reliability index using lognormal distribution of the random variable. The results obtained appear to be interesting.
Thermal investigation of Three-Phase Induction Motors with an Integrated Open- Phase Fault Operation Using a Lumped Parameter Thermal Network (LPTN)
(27/08/2019) Bouheraoua, Mustapha; Atig, Mahdi; Khaldi, Rabah
The authors of this article present an analytical method based on a Lumped Parameter Thermal Network (LPTN) in order to model the effect of an open phase fault on the thermal behavior of an induction motor under steady state and transient thermal analysis. The heat transfer generated by the conduction and convection in induction motor are discussed. The results obtained by the model developed are validated by experimental tests. The tested machine is a standard three-phase, 4-pole, 2.2 kW, 380 V squirrel cage induction motor of Totally Enclosed Fan Cooled “TEFC” design manufactured in Algeria by Electro-Industries.

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