Liste des Mémoires de Master
Étude ab-initio dans le cadre de la DFT des propriétés structurales et physiques de supraconducteur à haute température critique (SHTc) de type pnictides de fer (FeSe)
In this work, we presented a study on the structural, elastic, electronic, magnetic and optical properties of iron selenide. The calculations were performed by the Pseudo-Potential method which is based on density functional formalism (DFT), using local density (LDA) and generalized gradient (GGA) approximations. The doped (GdFeSe and CeFeSe) and undoped (FeSe) structural properties such as the mesh parameters (a, b and c) and the compressibility modulus, are calculated as a function of pressure and the results found are in agreement with those advanced by the experimental and other calculations. In the study of the electronic properties of FeSe, the energy gap value calculated with the GGA approach are in agreement with those of other calculations. As far as the elastic properties are concerned, we calculated the elastic constants with the GGA approach and the found values of the latter are very close to those of the experiment. We also calculated the magnetic moment and confirmed that FeSe is a non-magnetic material. For the optical properties, we calculated the different optical properties such as the function of the reflectivity, the refractive index and the absorption coefficient. Voir les détails
Mots clés : Superconductivity, pnictures, FeSe, DFT, pseudo potential, Castep
Etude des propriétés mécaniques et magnétiques des alliages Fe70Al30-xSixélaboré par arc melting
This study investigates the effect of Al substitution by Si on the structural, mechanical (Vickers HV hardness) and magnetic (hysteresis loop) properties of the Fe70Al30-xSix alloys developed by Arc Melting.Results show that the increase in Si content gives rise to the ordered phase DO3 (FeAl0.7Si0.3) starting from the composition Fe70Al15Si15; this last transition is accompanied by a drop in micro hardness HV and a remarkable variation in structural parameters such as relaxation of the crystals. Also, the substitution of Al by Si atomes decreases the cell parameter.Our choice of process and alloy is based on economic considerations (low cost) to understand the phase transitions in these alloys that are typical ones. Voir les détails
Mots clés : Fe-Al-Si alloys, Arc melting, Order-disorder transitions, solid solution bcc-Fe, Ordered phase DO3 (Fe3Al0.7Si0.3), micro-hardness HV, Hysteresis cycle, Coercive field, Remanent magnetization, Saturation magnetization
Contrôle du joint de soudure d’un pipeline par ultrasons
In this study, we have been adapted to the various techniques of non-destructive testing and especially non-destructive ultrasonic testing by contact of a piezoelectric transducer with welded parts (welded pipe). This method can detect, locate, dimension and identify defects in the weld seam after going through several steps such as calibration and tracing of the distance amplitude curve. The ultimate goal of this control is to accept or reject controlled parts according to international standards Voir les détails
Mots clés : Non-Destructive testing, - ultrasonic testing, welded pipe
Détection, positionnement, localisation et identification des défauts dans les matériaux solides par ultrasons
In this study, we have been adapted to the various techniques of non-destructive testing and especially non-destructive ultrasonic testing by contact of a piezoelectric transducer with welded parts (different types of welding). This method can detect, locate, dimension and identify defects in the weld seam after going through several steps such as calibration and tracing of the distance amplitude curve. The ultimate goal of this control is to accept or reject controlled parts according to international standards Voir les détails
Mots clés : Non-Destructive testing, piezoelectric transducer, different types of welding
Elaboration et caractérisation des composites stratifiés à base de fibres de carbone et de fibres de verre à usage aéronautique
This work is based on the elaboration and the characterization of different types of laminated composites based on epoxy resin, carbon fiber and glass fiber. These composites differ based on three essential parameters, including the type of reinforcements used, the orientation of the constituent fibers reinforcements and the heat treatment temperature at which these laminated composites were exposed. The characterization is then done to see the influence of these elaboration parameters on the physical and dynamic behaviors of this laminated composite materials developed during and after the solicitation. For this, we used nondestructive testing methods such as ultrasound and microscopy and destructive methods such as tensile and bending tests. The results obtained from the various tests were the subject of comparative interpretations followed by interesting perspectives. Voir les détails
Mots clés : Laminated composites, carbon fiber, Glass fiber, Epoxy resin, nondestructive test, mechanic tests
Apport des techniques de traitement de signal dans la localisation spatiale d’un défaut par ultrasons
Le contrôle non destructif (CND) est une étape importante dans un processus industriel. Il permet de contrôler l’intégrité des composants sans les endommager, pendant ou à la fin de leur fabrication, et en situation d’utilisation. Différents phénomènes physiques permettent ces contrôles de par leur caractère pénétrant dans les objets (ondes électromagnétique, ondes acoustiques, champs magnétique, etc.), menant à différents modes de contrôle. Nous nous intéressons dans ce travail au CND par ultrasons, modalité qui consiste à émettre des ondes acoustiques dans le matériau a inspecté. Les ondes se propagent dans le milieu, et récupérées par le capteur ultrasonore, permettent dans la mesure du possible de détecter et d’identifier les défauts contenus dans la pièce. Le même procédé peut être appliqué pour évaluer les matériaux, c’est-à-dire pour estimer des paramètres physiques propres, tels que la vitesse des ondes ou le coefficient d’atténuation. Le but de l’utilisateur est de visualiser les échos et d’en déduire une information spatiale sur l’objet inspecté. Nous nous intéressons aux discontinuités, qui présentent des transitions franches dans l’objet (surface, arrêts, défauts, etc.). L’analyse du signal peut cependant se révéler difficile a l’œil nu pour plusieurs raisons : bruit, atténuation, diffraction, superposition d’échos, etc. L’allure des échos rétrodiffusés (réfléchis) du signal ultrasonore, lors d’une opération d’inspection, donne une indication sur la forme géométrique, la taille et l’orientation des réflecteurs se trouvant sur la zone étudiée. Une estimation correcte et précise de la forme des échos ultrasonores est essentielle pour déterminer les propriétés du milieu de propagation. Des techniques de traitement du signal sont alors employées pour améliorer la résolution des signaux. Dans ce travail nous nous intéressons à la localisation spatiale d’un défaut dans une pièce métallique en appliquant des techniques de traitement de signal. Voir les détails
Mots clés : CND par ultrasons, ondes électromagnétique, ondes acoustiques, champs magnétique
Élaboration et caractérisation des matériaux nanostructures à base de Fe et Ni
The aims of this work is to understand the influence of the elaboration method , mill type, milling time and concentration on the structural, microstructural and magnetic properties of Fe80Ni20 nanostructured alloy. The production of the Fe80Ni20nanostructured alloy was carried out by the mechanical alloying technique of iron and nickel powders mixture. The elements produced (elaborated) were characterized by X-ray diffraction techniques (DRX), Scanning Electron Microscope (SEM) and Vibrating Sample Magnetometer (VSM). The X-ray diffraction study confirmed the formation of the Fe-Ni alloy after 600 min of milling with an average crystallite size of 13 nm, while the analysis of the magnetization curves of the Fe-Ni alloys, revealed original magnetic properties: super paramagnetic behavior, and especially saturation magnetization and significant coercitivity. Voir les détails
Mots clés : elaboration method, properties of Fe80Ni20, nanostructured alloy
Conception d’une chaîne de visionembarquée sur une plateforme FPGA
Our work consisted of a strategic development for the design and implementation of an embeddedvision chain with the use of a smart camera. The implementation of our vision chain for the acquisition ofvideo data is essentially based on the EMBV Python1300C embedded vision kit. The implementation of areconfigurable architecture is based on the exploitation of a Xilinx Zynq 7020 FPGA SoC Voir les détails
Mots clés : embedded vision chain, EMBV Python1300C, FPGA, ZYNQ-7000
Etude et élaboration d’un nouveau procédé de traitement des effluents industriels contaminés par les métaux par électrodéposition
Currently,Electrochemical methods find wide application in the treatment of industrial effluents to reduce their organic matter content, in inorganic sulphur compounds and nitrogen,or inharmful metals for the environment. Electrochemistry is not only applied to wastewater,but also on contaminated soils, incineration residuesor sewage sludge wastewater from the metallurgical industry. Electrochemistry has proved its effectiveness, which allowed him to integrate the environmental industry. Environmental electrochemical technologies allowto control pollution,to recycle materials,to carry out the rehabilitation of sites,monitoring (monitors and sensors for gases and liquids),the efficient conversion of energy, the prevention of corrosion, removal of contaminantsand disinfection of water. Electrochemical processes can therefore be efficient and economical when properly designed,and they integrate harmoniously with the environmental industry. These processes require compact installationsand can thus integrate into existing industrial waste treatment chains. The present work aims so the elaboration of an electrochemical process of treatmentand purification of industrial effluentscontaminate with metals. Indeed, the use of this technique can allow both the elimination of these metals by electroplating on a cathode,a recovery of metals, a saving of precipitation reagents and a reduction in the amount of sludge to be removed,as well as surface treatmentswhere the applications concern gold recovery, silver, copper, cadmium, nickel, zinc, iron and lead ... etc.The metal that can be recoveredin the form of valorizable cathodes,which allows the depollution of the environment. This work requires in-depth studies of design considerationsand the development of an electrolytic cell. Voir les détails
Mots clés : Electrochemical methods, inorganic sulphur compounds, inharmful metals
Effet de l’application d’une peinture anti-corrosion sur le comportement électrochimique de l’acier au carbone en milieu acide
In this work, we are interested in the evolution of the surface roughness of steel (mechanically polished (A2, A3) and shot-blasted (A2G, A3G)) and the thickness of the paint applied to different surface states (mechanically polished (A2P, A3P) and shot blasted (A2GP, A3GP)). Shows that the roughness of grit-carbon steel surfaces is greater than the mechanically polished ones. Although the evolution of the thickness of the paint deposited on mechanically polished and shot-blasted carbon steel, depending on the grade of polishing paper,), shows that the thicknesses of paint deposited on carbon steel surfaces shot blasted are larger than those polished mechanically. The characterization of the samples was determined by scanning electron microscopy (SEM), showing that the surface state of mechanically polished steel (A3) is much better than that of shot-blasted steel (A3G). The surface analysis by SEM also shows that the coatings applied on the shot-blasted steel (A3GP) have a much better morphology than those applied on mechanically polished steel (A3P), and the metallographic micrographic analysis shows that the thickness of the coatings of paints obtained on shot-blasted steel are superior than that obtained on mechanically polished steel, The effect of mechanical polishing and shot blasting on the behavior of carbon steel with respect to corrosion by the use of two electrochemical techniques: potentiodynamic method and electrochemical impedance spectroscopy (EIS). mechanically polished and shot-blasted steel with and without coating for better resistance to corrosion in hydrochloric acid medium. Spectral analyzes by FTIR, shows the evolution of chemical bonds and functional groups present in the paint applied to steel. Voir les détails
Mots clés : surface roughness of steel, shot-blasted steel (A3G), electron microscopy (SEM)