Liste des documents
Formulation of Mumford and Shah problem by level set
The limitations of the active contour based on borders have directed the research towards solutions wherethe contour is built from all the information contained in the image. They are known as region-based active contours. More robust to the noise and less sensitive to the position of the initial curve, the models based on regions have for general principle to develop a curve so that in the convergence, we realize a partition of the image in two homogeneous regions.We obtain two regions because a single curve bounds only two domains in image. The region-based active contours base generally on statistical. Voir les détails
Mots clés : Level set, Mumford-Shah, weld defect
Influence du courant de soudage sur la densité de courant , la température et la densité électrique.
l'objectif de notre travail est l'étude par simulation numérique de l'influence des courants de soudages sur la distribution des tensions, la densité de courant et la densité d'électron en fonction de la température et la distance inter-électrodes. Voir les détails
Mots clés : soudage TIG, élements finis, arc libre
Photolithographic processes for achievement miniature piezoelectric devices IDT
This paper deals transducer with the technology of piezoelectric IDTs (Interdigital transducers) by photolithographic technique, especially SAW (Surface Acoustic Waves) sensors. We conducted synthesis of thin layers of zinc oxide doped copper on glass substrates Corning glass, using Radio Frequency RF technology, then we elaborate interdigitated fingers IDT miniatures on glass substrates, silicon and quartz. Finally, a microlocation of ZnO piezoelectric on the IDT.We proceeded to the achievement of interdigitated fingers IDT, through microlithography technical, and deposition of layers of ZnO:Cu on IDT by sputtering RF technical. For this, we developed the insulation technique by projection mode optics. The main purpose of this technique is the miniaturization of devices IDT. Characterization techniques were implemented for characterizing of ZnO layers, such as the X-ray diffraction, the scanning electron microscopy MEB and optical microscopy for IDT devices. The minimum reduction is obtained of 1/ 30; this has yielded IDT for width and spacing of 5 microns. This technique has also improved the miniaturization factor an order of 30. Voir les détails
Mots clés : SAW sensor, fingers interdigitated IDT, Photolithography, Piezoelectricity, RF sputtering
Effet des contraintes sur le comportement électrochimique de l'acier austénitique 316L en milieu salin
L e but de ce travail est d'étudier l'évolution de la corrosion d'un acier inoxydable austénitique dans un milieu salin en fonction de taux de laminage Voir les détails
Mots clés : Acier inoxydable austénitique, corrosion sous contrainte, fissure
La simulation et étude de la corrosion de la ZATM du procédé FSW d’alliaged’Aluminium 6082 T651
Ce travail est un plus à l'étude de la soudabilité de l'aluminium par le procédé FSW. Il présente les microstructures obtenues après la simulation de la zone affecté thermomécaniquement de la soudure dans un équipement de simulation spécifique. Des observations métallographiques et des mesures de microduretés sont employées comme techniques de caractérisation et ainsi des essais de corrosion. Voir les détails
Mots clés : 6085T651, FSW, ZATM, corrosion
Modeling and Optimal Sizing of a Wind Energy System for the Electrification of an Algerian Territory.
Wind energy is a renewable energy promoting diversification energy independence of our country. So, wind power is probably the most promising sustainable energy resource. This paper makes easy the task of the assessment models of the power systems for a multitude of applications through a mathematical formulation which gives the stages of wind energy conversion system. Many decisions about the configuration of the system should be made, parameters optimized and losses due to wake effect reduced, a task that Homer takes in hand. It simulates the operation of a system by making energy balance calculations for each of the 8,760 hours a year. Voir les détails
Mots clés : Homer, mathematical formulation, wind turbine output power
Impacts of Inductive and Conductive Interference due to High Voltage Power Lines on Metallic Pipelines
The electromagnetic interference caused by power transmission lines to oil and gas buried pipelines is under investigation for many years. Especially during fault conditions, large currents and voltages are induced. Even under normal operating conditions, voltages and currents are induced on the pipeline that may pose danger to working personnel or may accelerate the corrosion of the pipeline’s metal. In this research, the induced voltage in the oil buried pipelines due to the magnetic fields produced by nearby 400kV transmission lines have been computed on normal and fault conditions Voir les détails
Mots clés : AC interference, Induced Voltages, Electric Power Transmission Lines, pipeline, AC Corrosion
Study of the morphological and optical properties of transparent electrodes based on indium tin oxide (ITO) for photovoltaic applications
Metal oxides are materials which may have the dual property of having a high electrical conductivity and good transparency in the visible range. They are called "transparent conductive oxides" TCO. The indium oxide ITO (indium tin oxide) is usually used as a transparent electrode as for the third generation solar cells.This work is devoted to the realization and characterization of transparent electrodes based on thin films of indium oxide doped with tin (ITO), which are deposited on a glass substrate by the method of spin-coting. After chemical treatment in specific locations we performed different characterizations.Optical characterization of transparent electrodes developed allowed us to deduce the various optical parameters such as transmission (170-2100 nm), the energy gap and extinction coefficient as a function of the thickness and the spectroscopic determination the refractive index n thanks to ellipsometry measurements. The AFM measurements characterize the surface topology of material and provide information in particular on the surface roughness and the grain size of the material studied. These measurements are performed using an atomic force microscope mode functioning contactThe obtained results on the preparation and characterization of transparent electrodes based on indium oxide ITO, shows that the ITO thin film has good transparency to visible light and also exhibits good conductivity thereby used as the transparent electrodes Voir les détails
Mots clés : transparent electrodes, ITO, thin film
Influence du courant de soudage TIG sur la microstructure et les propriétés mécaniques d'un alliage d’aluminium 2024 T3
L’utilisation des alliages d’aluminium prend de l’ampleur grace à leurs faible masse associé aux propriétés mécaniques élevées. Cependant, les problèmes rencontrés lors de de soudage limitent son application dans plusieurs domaines. Dans cette étude, des investigations microstructurales et de microduretés ont été menées sur des plaques minces en alliage d’aluminum 2024 T3 par le procédé TIG. Voir les détails
Mots clés : soudage, alliage d’Aluminium, TIG, microstructure
Propriétés microstructurales et mécaniques d’un assemblage WC-W-3Fe /WC-Co obtenu par brasage
Dans les outils de forage, l’assemblage du cermet WC-Co de taillant en PDC avec le consolidé de multi-matériau WC-W-3Fe obtenu par infiltration non conventionnelle est réalisé par brasage en utilisant un alliage d’apport (MA) à base d’argent. Une diffusion à faible échelle de l’Ag et du Co sur l’interface (MA)/WC-Co est mise en évidence. La caractérisation microstructurale du joint assemblé est effectuée à l’aide de la microscopie électronique à balayage couplée à l’EDS donnant une idée sur la distribution des constituants le long du joint, tandis que l’évolution des propriétés mécaniques est évaluée à l’aide d’un profil de micro-dureté HV0.3. Voir les détails
Mots clés : brasage, Cermet, infiltration, multi-matériau, interface.