Liste des publications
Energy storage based on maximum power pointtracking in photovoltaic systems: A comparisonbetween GAs and PSO approaches
In this paper, a comparison between GAs and PSO Approaches is considered to select andgenerate an optimal duty cycle which varies with photovoltaic parameter in order toextract the maximum Power from Photovoltaic System using real values of temperatureand insolation. The energy storage has very important role in renewable energy. To illustratethe energy storage, we have used a battery type lead-acid simulated in Matlab/Simulink. The obtained simulations results show the effectiveness and the robustness ofthe proposed approaches. Voir les détails
Mots clés : Photovoltaic systems, Chopper, MPPT, PSO, GAs, Energy storage
Pillared clays as catalysts for methyl parathion removal by advanced oxidation processes
A natural bentonite from Mostaganem in Algeria was modified by intercalation with polyoxocationic solutions (Al•Fe, Al•Co, Al•Cu, Al•Fe•Cu or Al•Fe•La). The modification of the bentonite occurred via pillaring by ionic exchange with these solutions. The addition of these solutions led to the formation of pillared clays with important catalytic properties in environmental impact reactions. The structural and textural properties of materials calcined at 500 °C were determined by several techniques: X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and N2 adsorption–desorption analysis. The pillared clays were then used as a Fenton-type heterogeneous catalyst for the heterogeneous sono-Fenton process for the oxidation of methyl parathion in water. The catalytic tests revealed the activity of the introduced iron species and the promoter effect of lanthanide or copper on the catalytic activity of these species. The sono-Fenton method showed promising results for the degradation of methyl parathion when compared with the Fenton method. Therefore, the sono-Fenton method can be a viable alternative technology to the existing methods for treating methyl parathion in wastewater. Voir les détails
Mots clés : Advanced oxidatio process, Sono-Fenton, heterogeneous catalysis, Methyl parathion pesticide, Wastewater treatment
DSC analysis of commercial Cu-Cr-Zr alloy processed by equal channel angular pressing
Samples of a commercial Cu-1Cr-0.1Zr (mass fraction, %) alloy were subjected to equal channel angular pressing(ECAP) up to 16 passes at room temperature following route Bc. Differential scanning calorimetry (DSC) was used to highlight theprecipitation sequence and to calculate the stored energy, recrystallization temperature and activation energy after each ECAP pass.On another hand, electrical properties were correlated with the dislocation density. Results show that the stored energy increasesupon increasing ECAP pass numbers, while the recrystallization temperature decreases significantly. Voir les détails
Mots clés : equal channel angular pressing (ECAP), Cu-Cr-Zr alloy, differential scanning calorimetry (DSC), electrical conductivity, stored energy
Numerical study of thermal Effects in the hydrodynamic Behavior of textured journal bearings
The journals bearing characteristics with texture presence on the bearing surface are investigated. The thermaleffect has been studied. The used numerical approach in this analysis is Finite Difference Method. The textured bearingperformance enhancement passes essentially by a minimum film thickness and a friction torque improvement through anappropriate surface texture geometry and right texture distribution on the bearing surface. It is found that the simulationresults are in good concordance with those issued from the litterature. The obtained results by considering thetemperature effect are more realistic. Voir les détails
Mots clés : Hydrodynamic lubrication, journal bearing, texturation, dimple
Surface texturing effect comparative analysis in the hydrodynamic journal bearings
The journal bearing is a complex system with high film convergence and with cavitation hydrodynamicphenomena. The surface texturation influence study on journal bearing performances requiresunavoidably experimental investigations followed by a numerical modelling of the problem. This work consistsin modellization and understanding of the journal bearing characteristics in both cases of presence orabsence of textures onto the bearing surface. The finite difference method is used as numerical approachin the analysis. The textured bearing performance enhancement passes essentially by an improvement of aminimum film thickness, a maximum pressure and a friction torque through an appropriate surface texturegeometry and appropriate texture distribution on the contact surface. It is found that the simulationsresults are in good concordance with litteratures. The texture area position on the bearing surface is theprimary endpoint for journal bearing performance enhancement. The best design of textured area dependsstrongly on the geometrical parameters and the journal bearing operating conditions. Voir les détails
Mots clés : Journal bearings, Reynolds equation, Hydrodynamic lubrication, Stribeck curve, texture
Adaptive Fuzzy Gain Scheduling of PI Controller for control of theWind Energy Conversion Systems
In this work, the Wind Energy Conversion Systems (WECS) based on doubly fed induction generator (DFIG) model is built.First, we consider the vector control strategy of the active and reactive powers in order to ensure an optimum operation. Thewhole system is presented in d-q-synchronous reference frame. After, the design of Adaptive Fuzzy Gain Scheduling ofProportional Integral Controller (AFGPI) for WECS is described, where the optimization by Fuzzy rules is utilized online toadjust the parameters of PI controller based on the error and its first derivative. Finally, the control of the active and reactivepower using fuzzy-PI controller is simulated using software Matlab/Simulink, studies on a 1.5 MW DFIG wind generationsystem compared with conventional proportional integral controller. Performance and robustness results obtained are presentedand analyzed. Voir les détails
Mots clés : wind systems, doubly fed induction generator, fuzzy control, fuzzy gain scheduling control, fuzzy PI control, PI controller.
Robust Control of Doubly Fed Induction Generator for WindTurbine Under Sub-Synchronous Operation Mode
This paper presents a modeling and a robust control of doubly fed induction generator for wind generation system. The wholesystem is presented in d-q-synchronous reference frame. The regulation of the electromagnetic torque , stator reactive powercontrol and neuronal controller are applied in order to control the rotor currents of the DFIG. For to improve the controllerrobustness, the study is validated through simulation using software Matlab/Simulink, studies on a 1.5 MW DFIG windgeneration system compared with conventional proportional integral controller. Performance and robustness results obtained willbe presented and analyzed. Voir les détails
Mots clés : wind power generation, modeling, Control, doubly fed induction generator, Neuronal controller, performances.
The effect of copper concentration on CdS/CZTSheterojunction properties
Cu2ZnSnS4 (CZTS) / CdS heterojunctions have been prepared by a successive deposition of CZTS and CdS thin films on glass substrates by spray pyrolysis and chemical bath deposition techniques respectively. The concentration of cupric chloride in the starting solution has been varied in order to investigate its influence on device properties. The realized CZTS/CdS heterojunctions were characterized by recording their IV characteristics at ambient and at different temperatures. The current-voltage (IV) characteristics of the different heterostructures exhibit a rectifying behavior with a good ideality factor ranged from 1.5 to 2.7. From these IV characteristics we have deduced the saturation current series resistance and barrier height of the devices. We found that these quantities vary from 0.22 to 1.68µA for the saturation current and from 300 to 2500 for the series resistance. We have deduced also that the potential barrier was found between 0.3 and 1.31eV. From these results we inferred that the realized structures are suitable for their applications as solar cells. Voir les détails
Mots clés : CZTS; heterojunction; spray pyrolysis; solar cells;IV
Adaptive backstepping control using combined direct and indirect adaptation for a single-link flexible-joint robot
In this paper, a new tuning functions based adaptive backstepping controller using combined direct and indirect adaptation for a single-link flexible-joint robot is presented. In this approach, the parameter estimation is driven by a weighted combination of tracking and identification errors. At first, the x-swapping filter identifier with a gradient-type update law is presented for a class of parametric strict-feedback nonlinear systems. Then, the main steps of the controller design for a single-link flexible-joint robot manipulator model are described. The closed-loop error dynamics is shown to be globally stable by using the Lyapunov stability approach. Finally, simulation results are given to illustrate the tracking performance of a single-link flexible-joint robot manipulator with the proposed adaptive control scheme Voir les détails
Mots clés : Backstepping control, direct and indirect adaptive control, combined adaptation, Lyapunov stability, flexible joint manipulators
Structural, Optical and Electrical Properties of PbS Thin Films Deposited by CBD at Different Bath pH
PbS thin films were grown on glass substrates by chemical bath deposition (CBD). The precursor aqueous bath contained 1mole of lead nitrate, 1mole of Thiourea and complexing agents (triethanolamine (TEA) and NaOH). Bath temperature and deposition time were fixed at 60°C and 3 hours, respectively. However, the PH of bath was varied from 10.5 to 12.5. Structural properties of the deposited films were characterized by X-ray diffraction and Raman spectroscopy. The preferred direction was revealed to be along (111) and the PbS crystal structure was confirmed. Strains and grains sizes were also calculated. Optical studies showed that films thicknesses do not exceed 600nm. Energy band gap values of films decreases with increase in pH and reached a value ~ 0.4eV at pH equal 12.5. The small value of the energy band gap makes PbS one of the most interesting candidate for solar energy conversion near the infrared ray Voir les détails
Mots clés : CBD, PbS, pH, Thin films, X-ray diffraction