Liste des documents
THE INFLUENCE OF ZnCl2 CONCENTRATION ON THE MORPHOLOGY OF THE ZnO DEPOSIT OBTAINED BY ELECTRODEPOSITION
Zinc oxide (ZnO) thin film and nanostructures have great potential for applications in the fields of optoelec-tronic, sensor devices and solar cells (photovoltaic). In this work, zinc oxide nanowires and thin films were electrodeposited on molybdenum substrates. Electrochemical deposition was performed with hydrogen peroxide as hydroxide ions source, the applied potential was -1.03 V versus silver-silver chloride electrode (Ag/AgCl), during 45 minutes at room temperature. The morphology and structure characterizations of nanowires and thin films of ZnO were carried out by scanning electron microscopy and X-ray diffraction. The resulting thin films and nanowires have a good crystallinity and had a high c-axis orientation. As the electrodeposition parameters have significant influence on the morphology the deposits, the concentration of ZnCl2 played a key role in this process. More researches can be performed by electrochemical deposition of ZnO on other substrates (copper, silicon, etc.) under ambient conditions and with different ZnCl2 concentration. Voir les détails
Mots clés : : ZnO, Thin films, nano-wires, electrochemical deposition
Study of a Solar Photovoltaic Regulator for Cathodic Protection Systems
Study of a Solar Photovoltaic Regulator for Cathodic Protection Systems Cathodic protection has divers known industrialapplications in buried or submerged pipes protection. The surrounding environment and the economic aspects are two decisiveparameters in the choice of the method of protection. When theenvironment conditions are well known and the method of protection properly mastered, the cathodic protection is generally cheap and efficient over a long period of time. The photovoltaic conversionrepresents a good issue to provide the needed autonomous energy forseveral applications. Since it has many applications, we are preciselyinterested in cathodic protection one. To well manage the use of thebattery, according to the desired application, it’s necessary to makean adequate choice of the type of the regulator of load. Theprevention opposes to the corrosion of the metallic deep pipes. Thus,a variable exit regulation for cathodic protection is studied. Thestabilization of the PV.G voltage guarantees a load of battery withfixed voltage. The charging current threshold takes into account oftwo parameters; the permanent measurement of the PV.G currentoutput and of the increase in its voltage. Voir les détails
Mots clés : corrosion, buried pipelines, photovoltaic System, cathodic protection, regulation, buck-boost converter, impressed current.
Monitoring and Fault detection of the Stator short circuit fault in induction motor based on the FuzzyLogic approach
the diagnostic of the induction machinesbecomes more and more important. This made necessarythe monitoring function condition of these machines forimproved an exploitation of the installation. The aim ofthis work is the proposal of a monitoring strategy based onthe fuzzy logic, that informs us about the healthy and faultoperating condition of short-circuit between turns of thestator windings. The principle adopted for the strategysuggested is based on monitoring of the average root meansquare (RMS) value of the stator current, which will beuseful as input data with the fuzzy logic block andconsidered to making decision on the machine state. Voir les détails
Mots clés : Induction Machine Monitoring, Detection, Fuzzy logic, RMS, modeling, Simulation.
Early detection of short circuit between turns in stator winding of induction machines via multivariate statistics
Online monitoring of induction machine health is of increased interest, as the industrial processes that depend on the machines becomes more complex and as performance to cost ration of monitoring technology. Several efforts have been directed towards developing methods that use the conventional signal processing and pattern classification techniques. This paper focuses on fault diagnosis in induction machines operating under transient conditions. A new tool of anomaly detection based on multi-scale entropy MSE of Park vector approach and information theory combined with current trajectory mass center with principal component analysis (PCA) are proposed. The faults study in this paper is short circuit between turns in stator winding of induction machine. Simulation results show that the proposed method are able to detect short circuit between turns in stator winding of induction machine in the permanent period. Voir les détails
Mots clés : Induction machine, Fault Diagnosis, Multi-scale entropy, principal component analysis, Current trajectory mass center
Caractérisation thermique et tribologique des composites thermostructuraux C-C et composite à matrice organique
Le comportement tribologique sec des couples acier-composite thermostructuraux carbone-carbone et acier-composite à matrice organique et les phénomènes dû aux frottements sont étudiés. En utilisant un modèle mathématique, la température superficielle du contact a été déterminée. Les résultats illustrent l’évolution de la température en fonction du temps. La charge normale, la vitesse de glissement et le coefficient de frottement ont une influence significative sur la variation de la température Voir les détails
Mots clés : température, frottement, acier, composite, disque, garniture
Modeling of temperature field at outlet of continuous casting mold
Continuous casting of steel is a complex industrial process, involving many factors and mechanisms. For steel makers it is very difficult to control the process parameters optimally to obtain a product free defect i.e. a quality with the best possible return. Numerical simulation is a tool that can be used to optimise the process parameters. This work has for objective to model the temperature field at the level of solidified skin at the outlet of the mold "Ts". There are , three important key parameters affecting the cooling process in the mold: The "immersion distance of the nozzle Di", the "casting temperature Tc" and the "casting speed Vc". Thes parameters are used as input parameters during a parametric study by the experiments: "box behenken" Plans. The "outlet temperature Ts" is measured on the consolidated layer of steel on leaving the mold. The simulation of continuous casting phenomen is carried out by the Fluent code 6.0. A relation between the above cited key parameters and the "outlet temperature Ts," was established by using the required algorithm. Thus, the optimal parameters were obtained by predicting a minimum threshold temperature (TSmin) at the outlet of the mold. Voir les détails
Mots clés : continuous casting, output tempetature, casting temperature, casting speed, distance immersion, model "box behenken."
FRACTURE BEHAVIOR AND MECHANICAL CHARACTERIZATION OF A COMPOSITE ORTHOPEDIC USE IN THE TWO DIRECTION OF FLOW MOLDING
A standard tensile test was carried out on prismatic specimens of glass-perlon reinforced acrylic resin laminate composite material of orthopedic use, developed by the National Office Equipments and Accessories for People with Disabilities, ONAAPH Annaba (Algeria). The measurement results of the Young's modulus and the fracture strength show a large scatter characteristic of these materials and are influenced by the cutting direction of the samples compared to the direction of molding. The use of the probabilistic two parameters Weibull's model made it possible to characterize brittleness and the fracture behavior of these materials and quantitatively to describe the probabilistic aspect of the latter. A report of the principal mechanisms responsible of the fracture is drawed up according to microscopic observations of the fracture topographies of the broken samples.weibull, glass, perlon,acrylic, orthopedic. Voir les détails
Mots clés : Weibull, glass, perlon, acrylic, orthopedic
Étude numérique de l’influence des mélanges gazeux dans un four de réchauffage
Ce travail s’inscrit dans le cadre d’une étude visant l’optimisation des paramètres de fonctionnement des brûleurs industriels à flamme de diffusion. L’exemple développé ici s’intéresse particulièrement à l’étude de l’effet des mélanges gazeux sur les caractéristiques dynamique et thermique de l’écoulement ainsi que leurs impacts sur la stabilité de la flamme et la composition du mélange. L’étude est menée sur un brûleur industriel à gaz de 250kilowatt. Les simulations numériques sont effectuées à l’aide du code de calcul FLUENT, en utilisant le modèle de turbulence k-ε standard couplé au modèle de combustion turbulente ED (Eddy Dissipation).les résultats obtenus pour un combustible considéré un mélange méthane-hydrogène. La proportion volumique d’hydrogène varie de 0 à 100%, montrent que la structure de l’écoulement et la forme de la flamme dans la chambre de combustion dépendent de la composition du combustible. Voir les détails
Mots clés : Brûleur industriel, mélanges gazeux, Simulation numérique, Modèle κ −ε Standard, Combustion Turbulente
Conception of fractional PIλ controllerthrough classical PI controller
Fractional order PIλDμ controllers are gaining more interests from the control community. They have been introduced in the control loops in a continuous effort to ameliorate the system control performances. In this work, the design of the fractional order PIλ controller derived through the regular PI controller used for the first order lag plus time delay control system is proposed. The main idea of this article is the tuning of the parameter λ of the fractional order PIλ controller to ameliorate the overshoot, the integral squared error and the settling time performances of the step response of the feedback control system compared to the ones of the feedback control system with the corresponding classical PI controller. The control quality enhancement of the proposed PIλ controller scheme compared to the corresponding classical PI controller has been presented through the simulation results of illustrative examples. Voir les détails
Mots clés : component; fractional order controllers; fractional order PI controllers; PI tuning, time delay.
Polypyrrole coated cellulosic substrate : synthesized and characterization
In this work, we report the simple chemical polymerization process with lron (III) chloride anhydrous (FeCl3) as an oxidant. To obtain thin film of polypyrrole (PPy) deposited onto the electrode of the cellulosic. The morphology of the surface of the PPy/cellulosic films were studied by the cyclic voltammetry (CV), electrochemical impedance spectroscopy (SIE), Fourier-transform infrared spectroscopy (FTIR), profilometer apparatus and scanning microscope (SEM) coupled with energy dispersive X-ray spectrometry (EDX). Voir les détails
Mots clés : Polypyrrole, electrode