Liste des Mémoires de Master

Nombre total de résultats : 48
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Effet du traitement de vieillissement sur l’évolution microstructurale et le comportement électrochimique des aciers inoxydables 2101, 2205 et 2507.

F.Z.ROUIBI  (2021)
Mémoire de Master

this work, the effect of ageing treatment on the microstructural evolution, morphology and potential distribution of LDX2101, SDX2205 and SDSS 2507 stainless steels is investigated. The heat treatment is carried out in two stages: solution treatment for one hour, then water quenching followed by ageing at 750°C for 2101 and 850°C for 2205 and 2507, for 24 hours holding time. Metallographical characterization is conducted using optical microscopy and scanning electron microscopy (SEM) as well as XRD analysis to identify the phases and precipitates formed after treatment. In order to study the effect of ageing on the morphological changes, magnetic behavior and potential distribution on the surfaces of the treated steels, different modes of atomic force microscopy (AFM) are used. The results showed a clear increase in roughness with a very heterogeneous potential distribution due to microstructural changes as a result of the formation of precipitates and secondary phases Voir les détails

Mots clés : LDX2101, SDX2205, SDSS 2507 stainless steels, The heat treatment

Elaboration et caractérisation des nanoparticules a base de chlorure d’étain SnCl2 et l’application d’élimination de colorants par adsorption

A. BOUCHENAK  (2021)
Mémoire de Master

Nanoparticles (NPs) have received considerable attention in recent years due to their unique physicochemical and optoelectronic properties and their applications in various sectors of chemistry, environment, medicine, agriculture and electronics. This dissertation will focus on three main parts, after an introduction to nanotechnologies: a bibliographic study on everything related to nanoparticles, their types, their synthesis methods, their characterizations, their properties and their applications. In the second part we have cited all the experiments of elaboration of our samples of nanoparticles (based on tin chloride) using the method of Co-precipitation so that at the end we have chosen the one that gives the best result to use it in the application of removal of methyl blue dye by adsorption. The third part shows that the results of our samples are excellent and from there we concluded that the nanoparticles (tin ferrites) and thanks to their magnetic behavior they allow to eliminate easily the methyl blue dye by magnetic field. Voir les détails

Mots clés : Nanoparticles (NPs), Magnetic field

Implémentation Des Algorithmes de Traitement du Signal sur carte FPGA

S.AISSAOUI, S. MOKHTARI  (2021)
Mémoire de Master

The aim of this work is to realize an on-board system allowing to automate the control in NDT by ultrasonic. For this, we performed the transmission and reception of signals using an FPGA card that acquisition and signal processing are implemented on the same FPGA circuit. Voir les détails

Mots clés : Non-destructive testing (CND), ultrasonic signals, FPGA, Signal processing

Elaboration et Caractérisation des Cuprates Supraconducteurs de type YBCO

Y. Louani  (2021)
Mémoire de Master

In this work, we prepared YBCO samples by sol-gel process and the gel decomposition studied by TG/DSC, which shows the X-ray diffraction due to the fact that the samples contained a preponderant phase (YBa2Cu3O7). SEM images showed the polycrystalline structure of samples with grain size between 2 and 3 µm and high porosity rate. Longitudinal and transverse ultrasonic velocity and attenuation measurements were performed on 3 mm thick samples. The experiments were performed at room temperature (300 K). The objective of this technique is ultrasonic characterization. Voir les détails

Mots clés : YBCO, sol-gel, XRD, DTA, Ultrasound

Etude D’efficacité D’inhibiteur NALCO E1154A Sur L’acier A36 Utilisé Dans Les Bacs De Stockage Des Hydrocarbures Du Site GTFT-ILIZI

CH. BENKARA, R. KHENTOUL  (2021)
Mémoire de Master

The corrosion of the condensate and LPG storage tanks in the GTFT zone presents a major problem that leads to a degradation of the storage tanks where huge sums are spent annually to protect the structures against corrosion, The maintenance and repair of the storage tanks. storage systems go through a detailed inspection program in order toobtain the data necessary to be properly adapted, today corrosion protection includes treatments such as cathodic protection, surface treatments or even the modification of the corrosive environment by addition of corrosion inhibitors. These constitute an original means of combating corrosion.In order to test the effectiveness of NALCO 115 EC 1154A inhibitor on A36 steel for use in the protection against corrosion of storage facilities for hydrocarbon products inthe GTFT zone, we were interested in this study to seek the optimal concentration in order to perform electrochemical tests. Voir les détails

Mots clés : corrosion, storage bins, inhibitors, A36 steel

Préparation et caractérisation des nanoparticules de ferrite de nickel dopée au Cérium par la méthode de coprécipitation

A. TALBI, A. SALHI  (2020)
Mémoire de Master

Nanocrystalline powders of cerium-doped nickel ferrite were synthesised by the coprecipitation method and the effect of the non-magnetic cerium content on the structural and magnetic properties was studied. X-ray diffraction (XRD) was used to determine the structure of NiFe2O4 nanoparticles. The surface morphology and chemical composition of the NiFe2O4 nanoparticles were obtained by scanning electron microscope analysis. The magnetic properties were studied by Vibrating Sample Magnetometry (VSM). Magnetic hysteresis cycles were measured with a maximum applied magnetic field of ≈ 1000Oe Voir les détails

Mots clés : NiFe2O4, cerium, co-precipitation, Magnetic Properties, DRX, SEM, VSM

Mise en œuvre de l’essai de fatigue sur des alliages d’aluminium

S. BENRABAH  (2020)
Mémoire de Master

The problem of fatigue of structures is commonly present in all sectors of the maritime, aeronautical, and mechanical and many other industries. In order to fully understand this harmful phenomenon, tests of different types of stresses are carried out at the laboratory level. This requires a good mastery of the test protocol. The analysis of the results obtained by these tests allows to study the behavior of the material. Our study consists in the implementation and the determination of the operating conditions of a uniaxial fatigue test with two types of specimens made of aluminum alloys of different thicknesses are tested. A tensile test is carried out to determine the mechanical behavior of the specimens and to have the necessary parameters to carry out a fatigue test, a metallographic study to characterize the specimens before carrying out the fatigue test. All the results obtained from the test are in the form of curves and a hysteresis loop. Voir les détails

Mots clés : Fatigue test, fatigue of aluminum, aluminum’s alloys

Comportement mécanique et métallurgique des jonctions hétérogènes soudées par friction rotative

A. CHERIFI, R. BELHOCINE  (2020)
Mémoire de Master

Rotational friction welding is a solid state welding process, which has seen spectacular development in various industries. It offers the possibility of producing very high quality solder joints in an extremely short time. The objective of this work is to improve the operating parameters of this process by changing the friction time (periods) and fixing the other parameters namely the speed of rotation [round per minute], the forging time [s], the friction and forging pressure [MPa]. The major problem with the disimmilar assembly of aluminum and stainless steel alloys is the low mechanical strength in the welded joint, due to the formation of certain unwanted inter-metal compounds during welding. An experimental procedure was used to obtain an Al6013-T8 /304L stainless steel welded joint with and without copper insertion. Different characterization methods were used namely x-ray diffraction, optical microscopy, HV microhardness and tensile testing. The Al6013-T8 side microstructure reveals the formation of two zones, the HAZ and the TMAZ at the center of the junction, unlike 304L stainless steel, which has not undergone any mechanical deformation. The microhardness of Al6013-T8 increased in the vicinity of the junction, and tensile testing revealed that the mechanical characteristics of the joints increase with increasing friction time. Voir les détails

Mots clés : Rotational friction welding, the speed of rotation, the forging time

Segmentation des images radiographiques

I. karmal, A. Henniche  (2020)
Mémoire de Master

Image segmentation is an important step in any image analysis process. The subject has already been tackled by multiple approaches. These approaches are based on various tools such as mathematical morphology, wavelet decomposition, active contours; some are based on the detection of contours and others on the identification of regions. Each of these classes of methods has its advantages and disadvantages. In this dissertation, we present the different segmentation approaches and we choose a hybrid method for segmenting chest X-ray images composed of two algorithms. One is the FCM as an initial contour for the other segmentation method LEVEL SET which is a variant of the deformable models based on the active contour method, we injecting the images resulting from this segmentation process into a convolutional neural network (CNN) in order to classify them according to the pathological state. Therefore the aim of our work is the implementation of a model for segmentation and classification of medical X-ray images to assist doctors in the detection of pulmonary pathologies. Voir les détails

Mots clés : image segmentation, chest X-ray image, Active contour, FCM, Level set, classification, CNN

Caractérisation des paramètres de fissuration en mode d'ouverture par corrélation d'images et éléments finis d’un alliage d’aluminium 2xxx

T. BELKACEM, A. BOUNEDJAR  (2020)
Mémoire de Master

In this work, a problem of fracture and crack resistance is studied, the 2000 aluminum alloy series available in market is chosen, in this context of fracture mechanics the structural durability and integrity of materials is investigated. Couple techniques are used, an experimental characterization assisted by the digital image correlation technique and finite elements based numerical simulations, the aim is to study the mechanical behavior in presence of cracks and determine the fracture toughness. Making use of theoretical notions, analytical formulas, experimental tests coupled by the recent digital image correlation technique and numerical simulations constitute an efficient protocol to characterize materials to resist against cracks. At the end of our work, the study was done to know the crack propagation in opening mode (mode I) and the stress evolution on the crack paths by the X-FEM extended finite element method. Voir les détails

Mots clés : failure in mode 1, stress intensity factor (SIF), Cracking, Correlation of digital images (CDI), FEM finite elements, Abaqus, Integral J, Extended finite element method (XFEM)