Liste des communications
ÉTUDE ELECTROCHIMIQUE D'UNE BASE DE SCHIFF SYNTHÉTISÉE VIS-À-VIS LA CORROSION DES ARMATURES DE BÉTON ARMÉ EN MILIEU CHLORURÉ
La corrosion des armatures est l'un des principaux facteurs limitant la durée de vie des bâtiments en béton armé [1,2]. L'acier dans le béton peut se corroder lorsque de nombreux agents agressifs pénètrent dans les pores du béton contenant de l'oxygène. Diverses méthodes existent pour protéger l'acier contre la corrosion. Ces méthodes comprennent l'utilisation d'inhibiteurs de corrosion ce qui reste un moyen de protection très facile et efficace. Dans cet axe de recherche, une base de Schiff (Composé -A-) a été synthétisée et testé pour voir leur action inhibitrice. Les parameters électro-chimiques et les caractéristiques de cette molécule vis-à-vis l'inhibition de ce type de corrosion ont été déterminés par voltampérométrie cyclique en exploitant les courbes de Tafel.Ce travail est basé sur les tests de corrosion à différents temps d'immersion on l'utilisant la voltamétrie cyclique Les taux d’inhibitions déterminées pour ce composé en béton est satisfaisante .Ces résultats indiquent que le groupe amine a peu d'effet sur l'efficacité d'inhibition de base de Schiff dans le béton[3,4]. Les résultats sont confirmés par microscopie électronique MEB. Voir les détails
Mots clés : Base de Schiff, inhibiteur de corrosion, armature de béton, chlorure.
Synthesis and characterization of ZnO nanogranules
In this paper, we report the synthesis of ZnO nanogranules by a solid state mixing of zinc nitrate tetrahydrate ZnO(NO3)2 with citric acid monohydrate C6H8O7, followed by aging and calcination at different temperatures of 400°C to 600°C. The crystallinity, structure and morphology of as prepared ZnO-nanocrystals have been characterized using powder X-ray diffraction (XRD), scanning electron Microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Optical properties of ZnO nanoparticles were also studied using an ultraviolet–visible (UV–vis) spectrophotometer. Voir les détails
Mots clés : Zinc oxide, nanogranules, ZnO nanopowder.
Diagnosis of the pipeline corrosion due to the inductive interference between high voltage power line and buried pipeline
In this paper, we study the interference between high voltage power transmission line and buried pipeline. The induced voltage onto the pipeline was calculated for the horizontal and the vertical configuration of the power line, the existence of the earth wire, various separation distances between conductors of the power line, and various separation distances between power line and pipeline. This effect results in a corrosion process which we have proposed some solutions. Voir les détails
Mots clés : Power lines, interference, induced voltage, induced current density, pipeline, AC Corrosion .
Parameters Identification for Jiles-AthertonModel using Genetic Algorithms
The aims of this work is the modeling of the hysteresis loop in ferromagneticmaterials, and allowed to highlight of the difficulty that exists in the choice of an model,both accurate and fast, for implantation in a calculation code field. Through this work, wetried to implement the means to incorporate the hysteresis phenomenon; we proposed aprocedure for the identification and optimization of the hysteresis loop by geneticalgorithms (GA). The obtained results by this method permit to get the hysteresis loopusing numerical simulation techniques. Experimental cycles on different samples allowedto us to identify the different optimized parameters and determine the GA approach on thecalculation of various parameters of the hysteresis loop. Voir les détails
Mots clés : Hysteresis Loop, Ferromagnetic Materials, genetic algorithms (GA), Jiles-Atherton Model.
Parameters Identification for Jiles-Atherton Model using Genetic Algorithms
The aims of this work is the modeling of the hysteresis loop in ferromagnetic materials, and allowed to highlight of the difficulty that exists in the choice of an model, both accurate and fast, for implantation in a calculation code field. Through this work, we tried to implement the means to incorporate the hysteresis phenomenon; we proposed a procedure for the identification and optimization of the hysteresis loop by genetic algorithms (GA). The obtained results by this method permit to get the hysteresis loop using numerical simulation techniques. Experimental cycles on different samples allowed to us to identify the different optimized parameters and determine the GA approach on the calculation of various parameters of the hysteresis loop. Voir les détails
Mots clés : Hysteresis Loop, Ferromagnetic Materials, genetic algorithms (GA), Jiles-Atherton model
Contribution to characterization of the diatomite forindustrialapplication
Diatomite also known Kieselguhr, is a non metallic mineral composed of the skeletal remains of microscopic single-celledaquatic algae called diatoms.The aim of this study was to test and to evaluate the diatomite of Sig region (West Algeria)tosubstitute the main mold powder used in continuous casting of steel for thermal insulation and lubrication. Generally, fluorineis added to mould fluxes to improve the viscosity. But this leads to the environmental pollution and the equipment corrosion. Thelaboratory and industrial investigations of diatomite have indicated the good results obtained in continuous casting of steel forthermal insulation and environmental protection against pollution (without fluorine). Also the characterization showed the hotbehavior of this product with the various transformations and could give the possibility to other use Voir les détails
Mots clés : diatomite, thermal insulation, lubrication, mold fluxes, fluorine
Study of the evolution of the mechanical properties of the steel pipe coatings in controlled environments
In this study, the experimental results are present the evolution of mechanical properties according to some aggressive environments with a coating of high-density polyethylene, steel pipe used for transporting hydrocarbons. The standard specimens tested in dumbbell shaped were prepared according to ISO 527. The mechanical properties are measured in traction using a computer-driven testing machine. The environments have shown that they have a real influence on the behavior of specimens subjected to uniform traction. The results are discussed in terms of curves (σ, ε). The tensile strength is generally between the values 19.5 and 25.5 MPa, this property comes after the total stretch of the specimen where it has been under severe strain that strongly influence the original structure of the material. In the synthetic oil, the elastic modulus is reduced by 42% and the yield strength collapsed completely in the case of 50% of the crude oil. Voir les détails
Mots clés : Pipe, agressive environnement, polyethylene, mechanical properties, degradation.
Etude et caractérisation de la biomasse « Pleurotus mutilus » en vue de son utilisation dans une application de traitement des eaux.
La bio-sorption des métaux lourds (Ni+2) par la biomasse morte « Pleurotus mutilus » a été étudié dans une colonne à lit fixe. Nos essais ont été réalisés en étudiant l'effet des paramètres tels que la hauteur du lit, pH, débits, concentrations initiales de la solution à traiter, sur la capacité d’adsorption de la biomasse. Ces mêmes essais ont permis d’obtenir des courbes de percées expérimentales. Les modèles de BDST, Thomas et Yoon-Nelson ont été utilisés pour estimer les capacités de la biomasse. Les essais de la régénération du biosorbant par l’acide hydrochlorique HCl (0,1M) a montré que l’efficacité de désorption des ions Ni+2 est supérieure à 78 %. Voir les détails
Mots clés : Bio-sorption, Ni2+, Biomasse, Pleurotus mutilus, Colonne à lit fixe.
Study of defects in X70 welds by NDT techniques
Despite having extensive reference of tungsten arc welding process, publications number which describes relationships between different TIG welding parameters is very low.In This paper, we presents a new approach to optimize of TIG welding parameters by non destructive testing system in order to determine a total number of weld defects for each weld parameter. Radiographic image processing and ultrasonic techniques are used for evaluation of two parameters TIG welding of API X70 High Strength Low Alloy (HSLA).Increasing welding current from 75 to 150A and welding frequency from 2 to 6 Hz causes radical changes in the nature and number of welding defects. A better combination between welding current and welding frequency is obtained for 120 A and 4 Hz. Voir les détails
Mots clés : TIG welding, radiographic, Ultrasonic, welding defect, welding parameter, X70 steel
OPTICAL PROPERTIES OF ZnO THIN FILMS DEPOSITION BY SPRAY PYROLYSIS
The aim of our work presented in this paper is the development and characterization of zinc oxide thin film (ZnO), using spray pyrolysis process (simple and cheap method). Tow conditions of deposition are used: temperature of sample Ts = 350 °C, the concentration of solution [Zn+2] = 0.01 and 0.4 mol.l-1. The films prepared are characterized by UV-visible to study the optical properties and the X-ray diffraction (XRD) for the structural one. The films obtained are composed of Nano-crystallites with average diameter of 18 nm. ZnO films have a transmittance over 80 % in visible range and band gap about Eg = 3.6 eV. Voir les détails
Mots clés : Thin films, ZnO, characterizations, Spray Pyrolysis.