Liste des communications
Structural characterisation and antibacterial activity ofPP/HDPE/TiO2-clay nanocomposites prepared by reactive extrusion
Compatible blends of polypropylene(PP)/hight density polyethylene (HDPE)were prepared byreactive blending in the presence of dicumyl peroxide (DCP)anhidride malic (MAH). The blends were characterized usingdifferent techniques: dynamical rheological analysis (DRA),differential scanning calorimetry (DSC), optical microscopy(OM) and scanning electron microscopy (SEM), dynamicalmechanical thermal analysis (DMTA), and impact strength, toevaluate their properties. The antibacterial properties ofPP/HDPE/TiO2-clay nanocomposites on E. coli Bacillus subtilisand S. aureus have been studied. Voir les détails
Mots clés : pp, ( dcp ), nanocomposite, antibacterial properties
Synthesis and characterization of antibacterialsilver-alginate - chitosan bionanocomposite filmsusing UV irradiation method
A simple, UV-based method for the preparation of alginate-silvernanoparticles-chitosan composite films is described herein. Alginate,a polysaccharide was simultaneously used as a natural stabilizer andreducing agent of silver ions (Ag+) delivered from silver nitratesolution. The properties of silver nanoparticles (Ag NPs) in alginateand alginate-Ag NPs-chitosan (Alg-Ag NPs-CTS) composite filmswere investigated in terms of their surface plasmon resonance (SPR),crystalline structure and morphology. The average diameter size, thedegree of swelling and functional groups distribution were alsoaddressed. Antibacterial activities were carried out against bothGram+ and Gram- bacteria cells; the synthesized nanocompositefilms displayed an interesting antibacterial activity. The perspectivesfor a potential use of these nano-composite films in areas such asbiomedical engineering may seriously be considered. Voir les détails
Mots clés : alginate, silver nanoparticles, green synthesis, chitosan.
Propagation caracteristics of chirped vector soliton in birefringent optical fibers with variable coefficients in the presence of third order dispersion
We study in this work, the propagation characteristics of chirped vector solitons in optical fiber systems using the compact split step Padé scheme (CSSPS). This study is done in the case of variable coefficients and the presence of third order dispersion. A negative chirp makes the soliton broadening, while; a positive chirp leads to a soliton compression. The effect of chirp on the soliton temporal width of an amplification system (σ>0) is greater than that in a loss system (σ<0). In the presence of third order dispersion, we note an increase of the pulse width with an asymmetric oscillation on the trailing edge. In the same time, we note a shift of the center of the two components of the one managed chirped vector soliton along the propagation distance. Voir les détails
Mots clés : vector soliton, chirped soliton, optical fibers, compact split step Padé scheme, coupled higher-order nonlinear Schrodinger equations, dispersion management, nonlinearity management, temporal waveform, third order dispersion.
Microstructural and tribological characterizations of a Hard material composite: WC-WMn-Ni/Cu-Sn/assembled with cermet (WC-Co) by brazing process.
This study focuses in microstructural and tribological characterizations of an assemblage.This assemblage is a Hard Materiales composite obtained by infiltration process of loose powder(WC/WC- W-Cu-Mn-Ni) using bronze alloyed with Ni as binder, assembled with cermet (WC-Co) bybrazing process using filler metal of Ag basic(Ag21Zn16Cu8Mn5Ni),2Hard Materiales composites or Cemented carbides are heterogeneous materials [1]; they are a classof metal matrix composites (MMCs) [2].The main feature of the hard metals composites is the combination of a tough metal binder with ahard material phase. This arrangement of phases offers an enhanced performance of certain materialproperties such as an excellent wear resistance [3_5]. This assemblage used in our study is similar tothe Diamond tools with PDC (Polycrystalline Diamond Compact) obtained by infiltration and brazingprocess, used in the field of oil and mining.Microstructural characterizations show a strong interaction between the binder phase andcompounds of powder in the infiltration process. The interface formed by the brazed joint is due tothe wide diffusion between the two assembled materials and there is formation of an inter-diffusionzone. Tribological caractérisations show, the wear behavior of materials is a complicatedphenomenon due to many variables governing it, such as sliding parameters, materials properties,abrasive effects etc. Voir les détails
Mots clés : powder, infiltration, Brazing, diffusion, interfaces, wear.
CHARCTERISATION MICROSTRUCTURALAND MECHANICALOF Ni/NiAl2O, DEVELOPED BYMECHANICAL ALLOYING AND REACTIVE4SINTERING.
This study concerns the development of Nickelmatrix composite; this composite was obtained after high-energyball milling for long time of milling. The initial powders mixedare the Nickel oxide and Aluminum, the reduction of Nickel oxideby Aluminum called Aluminothermic reaction. The high energymilling active the aluminothermic reaction and occurred theNickel-based composite, after milling we obtained powdercomposite with low density, which it necessary to following thisprocess by reactive sintering. The milling and the sintering wasperformed under argon atmosphere. The reactive sintering athigh temperature allows composite with high density. Aftersintering at 800 °C we obtained Ni/NiAl2O4.The powders milledand the samples sintering were characterized by X-raydiffraction, scanning electron microscopy, and the grain size ofpowders milled measured by laser analyzer granulometry. TheNickel aluminate (NiAl2O4) obtained has been applied innumerous fields to its high thermal stability and specific catalyticproprieties. Voir les détails
Mots clés : Ni/NiAl 2 O4, reactive sintering, reactive milling, powder metallurgy, Aluminothermic reaction.
Elaboration et Caractérisation des Films Minces de Sb- SnO2 par Voie Sol-Gel
Les films d'oxyde d'étain dopé en antimoine Sb- SnO2 (Sb = 14 at%) ont été synthétisés sur des substrats de verre par la méthode Sol-Gel .Ils ont été trouvés uniformes, adhérents et amorphes. après traitement thermique à 600 ° C pendant 1H, les films se révèlent être cristallins, avec une structure tétragonale cassitérite. Certains paramètres optiques de ces films, tels que l'indice de réfraction (n), coefficient d'extinction (k), le coefficient d'absorption (α) et la largeur de bande interdite ont été étudiés par la méthode Swanepoel dans un domaine compris entre 300-800 nm. On constate que le gap Eg augmente après le traitement thermique qui est de l'ordre de 4 eV. Voir les détails
Mots clés : oxyde d’étain, sol –gel, DRX, propriétés optiques, le gap.
Elaboration and Tribological study of WC-35wt%(Fe-Co-NI)hard metal alloys obtained by liquidphase sintering
this study concerns on the mechanical behavior(friction wear) of WC-35wt% (Fe-Ni-Co)hard alloy. The alloywas prepared by liquid phase sintering process with atemperature of 1350 ° C under argon. Haw ever This alloy isworking under severe conditions of wear and friction. haveundergo a series of dry friction tests involving multipleparameters. Interesting results have been obtained (good wearresistance and a stabilization of the friction coefficients). Thewear rate (mm3 / m) increases with increasing of the applied load5N and 10N, these results open up broad prospects for their jobsin the petrochemical fields (drilling tools, turbine parts). Voir les détails
Mots clés : friction, WC, phase, alloys, Sintering, wear
Investigation of Structural and Superconducting Properties ofBiSrCa(Ti)CuO Superconducting Ceramics from Sol-Gel Method
Superconducting Bi2Sr2Ca1-xTixCu2Oceramics samples have been prepared by Sol-Gel methods; (using citrateprocess).The influences of the preparation conditions of compound oxide powder on structural andsuperconducting properties have been investigated by x ray diffraction (XRD), Scanning Electron Microscopy(SEM)equipped with EDS.The critical transition temperatures T8have been determined by resistivity versustemperature measurements. Cell parameters samples were calculated from XRD patterns. The polyacrylamid gelmakes the citrate process easier, more rapid and affords the possibility of synthesis of high quality oxidepowders.c Voir les détails
Mots clés : Superconducting, Sol-Gel - Polyacrylamide Gel
Development of a magnetron sputtering system for in-situ deposition of thin multilayerscoatings.
In house Physical Vapor DepositionDualMagnetron Sputtering System (PVD-DMSS) was designed and manufactured based on basis criteria, relevant on R&D and industrial systems, and on the feedback experience acquired from operation of an old classical physical vapor deposition system of our laboratory. Its permit to elaborate in situ multilayer’s thin films without breaking vacuum and with varying several operation parameters, namely the inter-electrode distance, substrate rotation, polarization and the heating of substrate. The sputtering chamber of developed PVD-DMSS has a volume of about 10 liter; equipped with many accesses (for loading/unloading of samples, for the control of operation parameters and for the installation of diagnosis instruments). The PVD-DMSS is also equipped with two planar balanced magnetron cathodes providing magnetic field of 400mT, the cathodes can be powered by either a radiofrequency alternative current or continuous current, and connected to a high vacuum system. Monolayer’s and multilayer’s Nickel and Titanium thin films obtained and the results of plasma diagnosis make obvious that the PVD-DMSS developed allows a good level of operation flexibility as well as obtaining reproducible thin films and multilayer with a desired quality. Voir les détails
Mots clés : Magnetron sputtering, thin film, plasma diagnostic, PVD system design
Study of corrosion resistance of carbon steel in albian water solution in the presence of Chimec as corrosion inhibitor
The N80 steel has been generally used as the main construction material for down hole tubular, flow lines and transmission pipelines in petroleum industry. Electrochemical polarization and electrochemical impedance spectroscopy measurements were performed in order to obtain information on the corrosion behaviour of steel N 80 in the presence of a penetrating Chimec corrosion inhibitor. The investigation was performed in albian water from a well in the Hassi-Messaoud region, in the presence and absence of inhibitor and the effect of temperature on the corrosion was investigated. The electrochemical results indicate that the inhibitor is able to penetrate through the reinforcing steel, minimising steel corrosion. Voir les détails
Mots clés : Corrosion inhibitors, N80 Steel, Albian water, electrochemical impedance spectroscopy.