Liste des documents
VALORISATION DE COPRODUIT ISSU DE LA FABRICATION D’ACIER AU NIVEAU DU COMPLEXE SIDERURGIQUE D’EL-HADJAR ET APPLICATION DANS LA PEINTURE ANTICORROSIVE
Le but de ce travail est la valorisation d’un coproduit issu de la fabrication d’acier du complexe sidérurgique d’El-Hadjar, à savoir la calamine. Dans cette étude nous avons utilisé un mélange composé de ce produit et d’un pigment de fer afin d’obtenir un pigment d’oxyde de fer pour application dans le domaine de la peinture anticorrosive. Plusieurs essais ont été menés sur des mélanges préparés avec différents pourcentages de pigment de fer et de calamine. Les différentes caractéristiques de cette peinture ont été réalisé (extrait sec, densité, viscosité, test de corrosion). Les résultats obtenus montrent que l’utilisation de ce nouveau mélange comme pigment anti corrosif donne des résultats encourageant. Voir les détails
Mots clés : Pigment de fer, peinture anticorrosive, oxyde de fer, calamine
ÉTUDES STRUCTURALE ET MORPHOLOGIQUE DU DECHET INDUSTRIEL SIDERURGIQUE : SCORIE
Les scories sont générées lors de la purification de l’acier suite à l’introduction d’additions riches en calcium tels que le calcaire ou la chaux. Ces matériaux réagissent avec les composés indésirables tels que l’aluminium ou le silicium et forment des composés complexes non-métalliques de densité inférieure à celle du fer et de l’acier. L’objectif principal de ce présent travail est l’étude des caractéristiques de coproduit provenant de l’usine sidérurgiques El-Hadjar (scorie). La caractérisation de scorie choisis va être effectuée par la microscopie optique pour l’étude morphologique, la diffraction par rayon X pour la caractérisation physique et chimique, l’identification des différentes liaisons chimiques ( Al-O, Ca-O, et Si-O )se fait par spectrométrie infrarouge Voir les détails
Mots clés : caractérisation, Scorie, Propriétés chimiques, Déchets sidérurgiques
damage analysis of composite materials
Fiber reinforced composite materials have been increasingly used as structural material in airplanes and in space applications because of their high specific stiffness and strength. This work presents the results of the damage kinetic of carbon fiber reinforced polymer using the acoustic emission under solicitations. The correlations between acoustic emission parameters and damage mechanism are identified, and then confirmed by microscopic observations. This review will emphasize the roles that AE can play as a tool for the composite materials, damage mechanisms, and characterization of damage evolution with increasing time or stress, the localization and origin of damage, quantification of crack size based on energy release from concrete structures in the field and reduction in the numbers of test specimens required in various studies. Voir les détails
Mots clés : kinetic, damage, simulation, energy, acoustic emission.
KINETIC DAMAGE ANALYSIS OF COMPOSITE MATERIALS USING ACOUSTIC EMISSION
Fiber reinforced composite materials have been increasingly used as structural material in airplanes, because of their high specific stiffness and strength. Structural design and non destructive test techniques have evolved as increased emphasis has been placed on the durability and damage tolerance of these materials. This work presents the results of the damage kinetic of carbon fiber reinforced polymer using the acoustic emission under solicitations. The correlations between acoustic emission parameters and damage mechanism are identified, and then confirmed by microscopic observations. This review will emphasize the roles that AE can play as a tool for the composite materials, damage mechanisms, and characterization of damage evolution with increasing time or stress, the localization and origin of damage, quantification of crack size based on energy release from concrete structures in the field and reduction in the numbers of test specimens required in various studies. Voir les détails
Mots clés : Composite material, damage, Correlation, mechanism, localization
METALLURGICAL AND ELECTROCHEMICAL BEHAVIOR OF S295 STEEL TUBES IN STEEL COOLING CIRCUITS
Corrosion damage to industrial cooling systems in steel mills is a serious problem for industry and the environment. In order to reduce this phenomenon by the subsequent development of organic-based corrosion inhibitors, a preliminary identification study of the base material and the surrounding environment of the cooling circuits is essential. To monitor the electrochemical behavior of unalloyed steel tubes, we studied the influence of the "industrial cooling water" environment and the most influential physical parameters. This behavior of S295 grade steel will be determined by different stationary and non-stationary electrochemical methods, notably electrochemical impedance spectroscopy. These investigations enabled us on the one hand the metallurgical knowledge of the base material, the nature of the corrosive medium, and on the other hand the evaluation of the potentials and the corrosion rates and to define the different reactions at the metal interface. middle. In conclusion, the tubes studied in unalloyed steel have a low resistance to corrosion under the effect of the aggressiveness of the surrounding environment (Figure 1) in this case industrial cooling water hence the need to introduce corrosion inhibitors in cooling circuits. In our case, we will focus on natural organic inhibitors that ensure an economic and environmental balance. Figure.1: Stationary and frequential electrochemical curves of the material / medium interaction Voir les détails
Mots clés : steel, corrosion, behavior, cooling water, impedance, Temperature
Synthesis and characterization of nickel nanoparticles supported on aluminum oxide
Due to their peculiar qualities, metal-based nanostructures have been extensively used in applications such as catalysis, electronics, photography, and information storage, among others. New applications for metals in areas such as photonics, sensing, imaging, and medicine are also being developed. Significantly, most of these applications require the use of metals in the form of nanostructures with specific controlled properties. The properties of nanoscale metals are determined by a set of physical parameters that include size, shape, composition, and structure. In recent years, many research fields have focused on the synthesis of nanoscale-sized metallic materials with complex shape and composition in order to optimize the optical and electrical response of devices containing metallic nanostructures. In This work, we study nickel nanoparticles supported on aluminum oxide, prepared by impregnation with ionic exchange. In a first stage, the fixing conditions of the nickel precursor on aluminum oxide are optimized. In the second stage, the samples are calcined at temperature (T= 750 °C). Several experimental techniques are used for the characterization of the samples at the various stages of their elaboration (SEM, DRX, and VSM). A change of morphology of the aluminum oxide grains was observed by Scanning Electron Microscope. The X-rays diffraction shows the formations of nanoparticles Al3Ni2 of near size 16.7 nm. The extracted magnetic measurements show the good and the easy magnetization Voir les détails
Mots clés : nanostructures, Ionic exchange, Nickel nanoparticles, calcination
Asymmetric Generalized Gaussian Distribution Parameters Estimation based on Maximum Likelihood, Moments and Entropy
In this paper, we address the problem of estimating the parameters of Asymmetric Generalized Gaussian Distribution (AGGD) using three estimation methods, namely, Maximum Likelihood Estimation (MLE), Moment Matching Estimation (MME) and Entropy Matching Estimation (EME). For this purpose, these methods are applied on an unimodal histogram fitting of an image corrupted with AGGD noise. Experiments show that the effectiveness of each method comparatively to the other one depends on the variation range of the shape factor. Voir les détails
Mots clés : Asymmetric generalized Gaussian distribution, Parameter estimation, maximum likelihood, Moments, Entropy
Thermal analysis of aging of a matrix polymer material reinforced with a glass fiber.
The objective of this work is to evaluate the influence of temperature variation on the oxidation induction time of a fiberglass-reinforced polymeric matrix material for prosthesis of a tibia.To do this, we used the differential scanning calorimetry (DSC) technique to calculate the oxidation induction time this last one is the time needed to start the oxidation of the material in an oxygenated environment with an isotherm. And thanks to which we could determine the variation of an isotherm for different temperatures as a function of time.The experimental results obtained show that the time required to start the oxidation of the material in an oxygenated environment with an isotherm (OIT) decreases with the increase of the temperature of the sample this is confirmed by a hardness test. Voir les détails
Mots clés : thermal analysis, Polymer material, Oxidation induction time (OIT), hardness test
Comparison in Temperature evolution and Mechanical properties of an aluminium alloy welded by FSW and TIG processes
The purpose of this study is to show the potentiality of Friction Stir Welding (FSW) for joining the 2017A aluminium alloy, which is difficult to be welded by fusion techniques. A comparative study of FSW with a conventional fusion process as Tungsten Inert Gas (TIG) is made. FSW welds are made up using a specific tool mounted on a milling machine, however a single pass welding was applied to obtain a TIG joint. Thereafter, the comparison between the two processes has been made on the mechanical properties and thermal behavior. The results show that the thermal cycle peak induced by FSW process are lower than that induced by TIG process about 25%. Because the FSW does not need to melt the materials during welding. Microstructural examination revealed the grains refinement of the FSW weld joints that induce better mechanical properties (tensile tests and microhardness), higher joint efficiency (more than 80%) and good ductility compared to TIG joint. FSW process currently opens a great opportunity of application in the industrial and transport fields. Voir les détails
Mots clés : FSW, TIG, aluminum, Temperature, tensile joint efficiency, Microhardness
OPTICAL, STRUCTURAL AND MORPHOLOGICAL CHARACTERIZATION OF ELECTRODEPOSITED CUPROUS OXIDE THIN FILMS: EFFECT OF DEPOSITION TIME
The purpose of this work is the development and characterization of a novel electrode material based on copper oxide (Cu2O) for use as electrode in catalytic application. The samples are prepared on an indium doped tin oxide (ITO) glass substrate using a simple electrochemical deposition process from a solution of copper (II) sulfate and citric acid. The Cu2O films are deposited under chronoamperometric control at a potential of −0.50V versus SCE at different deposition times ranging from 2 to 15 minutes. The solution was maintained at a temperature of 60°C and a pH of 11. The effect of the deposition time is mainly examined in terms of the change in structural, morphological and optical properties of the Cu2O films using various characterization techniques. Atomic force microscopy (AFM) images showed that the prepared thin films are homogeneous with a granular shape. Also, the surface of the deposits becomes roughened with increasing deposition time. Scanning electron microscopy (SEM) images showed that the morphology of the prepared thin films is composed of a mixture of cubic and pyramidal shapes regularly distributed over the surface of the substrate. X-ray diffraction (XRD) measurements demonstrated that Cu2O thin films prepared by electrochemical deposition have a pure cubic structure with higher preferred growth orientation (111) and good crystallinity. Characterization by UV-Visible spectroscopy showed that the samples have high absorption in the visible region. The calculated values of the direct band gap are between 1.9 and 2.15 eV. These results represent a good starting point for the development of low cost anode used in catalytic application. Voir les détails
Mots clés : Cu2O thin film, electrodeposition, deposition time, optical properties