Nombre total de résultats : 204
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Application of the Algerian diatomite in adsorption of diclofenac

Ouafia Ghabeche1, 2, Skander Boukhezar1, Mohamed Boulkra1, Hazem Meradi1, Sihem Benayeche1, Hinda Gueroui1, Naima Touati1, Kotbia Labiod1, Fayçal Aouadja1, Ouafia Ghabeche, Skander Boukhezer, Mohamed BOULKRA, Hazem MERADI, Sihem BENAYACHE, Hinda Gueroui, Naima Touati, kotbia LABIOD (2018)
Article de conférence

Mesoporous amorphous silica of non-toxic nature has interesting properties, in particular, its relatively large surface area, pores with adjustable diameter and abundant Si-OH bonds. The functionalization of this silica transforms it into an ideal candidate for biological applications such as cell marking, gene transfection or as contrast agents in MRI and especially in drug delivery systems. In this study, we try to use a natural amorphous silica: Algerian diatomite, for encapsulation and carrier of Diclofenac (DS), in this order, diatomite must be purified; the choice of purification mode plays an important role in the organization and volume pore of the final product. We use hydrochloric acid HCl (1%, 10%, 20%) for oxide removal, and then we test the treated diatomite in the absorption of the DS.Voir les détails

Mots clés : diatomite, mesoporous, absorption, diclofenac sodic, drug carrier, encapsulation


Article de conférence

With the complex examination of raw material from a Sig deposit in Algeria in the region of Mascara area, physical, chemical and mineralogical properties of diatomite have been defined. It has been found that it is a dominantly amorphous material, sedimentary rock of the type silica-diatomite. The raw material consists of approximately 60% SiO2. Of the physical properties, more significant is porosity, which is higher than 60%. The raw material has a wide spectrum of possibilities for practical application: intensive absorbent for several types of liquids and chemical properties of the soil, natural insecticide, and filter water etc. For determination of the chemical contents, properties and origin of the raw material the following methods have been used, such as, chemical analysis, XRD analysis, optical microscopy and thermal analysis.Voir les détails

Mots clés : diatomite, X-ray, XRD, Sig.

Risk of Contamination of the Littoral lands by the mill scale in Annaba City-Algeria

B. Maalem, A. BALASKA, D. BERDJANE, L. Tairi, S. Djemili (2018)
Article de conférence

A significant amount of scale is produced during casting of ingots and processing of hot-rolled products. In the El Hadjar steel complex, during the various rolling operations, the amount of scale produced is approximately 0.1% of the annual production of the rolling mills. The quality of the thin sheet during rolling is affected by the behavior of the iron oxide layers formed on their surfaces. For this reason, acids and oils are used for the descaling of slabs and billets by means of pressurized water. The calamine, contaminated by these various acids and used oils, is rejected and stored involuntarily on important areas and pollutes soil and groundwater. Micrographic observations as well as x-ray diffraction analysis have shown that calamine consists mainly of iron oxides. Hematite and magnetite become the main components for oxidation times greater than 1 hour. Characterization tests have shown that calamine is dense (ρ = 4.8 g/cm3), its particle size is variable depending on the degree of oxidation (from 0.5 to 10 mm). Simultaneous thermal analysis showed that an increase in mass of the calamine sample with a release of heat. Studies are underway for the physico-chemical characterization of the soils of the storage areas.Voir les détails

Mots clés : Scale, Risks, soil, thermal analysis, granulometry, X-ray diffraction

Contribution à la détection des défauts dans les aciers au cours de leur solidification

TAYOUB Hadjira, BENDJAMA Hocine, HAMLAOUI Katib (2018)
Article de conférence

Le procédé de coulée continue occupe aujourd’hui une place importante dans l’industrie sidérurgique. Ce procédé se situe entre l’élaboration de l’acier et le laminage. Il est responsable principalement de la production de l’acier. Partant d’un acier liquide contenu dans une poche qui est coulé ensuite dans une lingotière sans fond, on obtient en sortie de machine de l’acier solide sous le format de brames, blooms ou billettes. Sous la lingotière sont disposés des rouleaux extracteurs qui font avancer le produit dans la machine. Entre ces rouleaux, un système de refroidissement est constitué de jets d’eau (refroidissement secondaire), pendant que la coulée progresse, l’épaisseur de la couche solidifiée augmente pour obtenir un produit complètement solidifié et qui admet des défauts (criques, ségrégations,...). Donc la qualité du produit obtenu est fortement dépendante du réglage du refroidissement secondaire. Pour cette raison, le présent travail consiste à étudier la présence des défauts dans les produits coulés lors de son passage en refroidissement secondaire.Voir les détails

Mots clés : acier, Coulé continue, refroidissement secondaire, défauts, solidification

Infiltration behavior of Cu and Ti fillers into Ti2AlC/Ti3AlC2 compositesduring tungsten inert gas (TIG)brazing

N. Chiker, A. Haddad, Y. Hadji, M.E.A. Benammar, M. Azzaz, M. Yahi, T. Sahraoui, M. Hadj, M.W. Barsoum (2017)
Article de journal

Herein we study the infiltration behavior of Ti and Cu fillers into a Ti2AlC/Ti3AlC2MAX phase composites using aTIG-brazing process. The microstructures of the interfaces were investigated by scanning electron microscopyand energy dispersive spectrometry. When Ti2AlC/Ti3AlC2 comes into contact with molten Ti, it starts decomposinginto TiCx, a Ti-richandTi3AlC; when in contact with molten Cu, the resulting phases are Ti2Al(Cu)C, Cu(Al), AlCu2Ti and TiC. In the presence of Cu at approximately 1630 °C, a defective Ti2Al(Cu)C phase was formedhaving a P63/mmc structure. Ti3AlC2 MAX phase was completely decomposed in presence of Cu or Ti fillermaterials.The decomposition of Ti2AlC to Ti3AlC2 was observed in the heat-affected zone of the composite.Notably, no cracks were observed during TIG-brazing of Ti2AlC/Ti3AlC2 composite with Ti or Cu filler materials.Voir les détails

Mots clés : MAX phase, Joining, microstructure, hardness, Brazing, TIG process

Effect of Welding Process on Microstructure and Mechanical Properties of Duplex Stainless Steel Welds

A. Kellai, A. LOUNIS, S. Kahla, A. Boutaghane (2017)
Article de conférence

The purpose of this study is a comparison between the effect of two electrical arc welding processes, on the structural and mechanical behavior of 2205 duplex stainless steel weldments, the first one is the manual process GTAW and the second one is the automatic process SAW. This effect has been identified and examined in the different welding area namely, the base metal BM, the heat affected zone HAZ and the weld metal WM, using optical metallographic techniques and mechanical methods by hardness tests.Voir les détails

Mots clés : duplex stainless steel, welding, microstructure, mechanical properties

Surface characterization of cold worked Ti-6Al-4V Titanium Alloy

L. Rabahi, N. KHERROUBA, B. Mehdi, R. Badji (2017)
Article de conférence

Titanium based alloys are widely used as structural materials in aerospace and biomedicalindustries. Among them, Ti-6Al-4V system containing α and β mixture is the most developedand used in the world. In the present work, the effects of cold rolling and post annealingtreatment on the surface morphology of Ti-6Al-4V alloy are investigated. To this purpose,Atomic Force Microscope (AFM), Scanning Electron Microscope (SEM) and X-rayDiffraction have been used to carry out experiments. A comparative study was performed andthe results highlight pertinent and particular features of the alloy surface morphology and α/βinterface.Voir les détails

Mots clés : Ti-6Al-4V, Cold rolling, AFM, SEM, Surface morphology


R. Benchouieb, D. BERDJANE, S. Achouri, O.GHELLOUDJ, F. LEMBOUB (2017)
Article de conférence

An approximate model for predicting static recrystallisation of ferritic stainless steel type 430, in hot rolling is proposed. In this model, the effect of variables such as strain, strain rate, temperature and initial grain size were considered during hot rolling operations. A set of integrated mathematical models for predicting static recrystallisation evolution during hot rolling has been developed through laboratory research work experiments. It consists of many sub-models such as percentage of recovery, recrystallisation kinetics, time for 50 percent of recrystallisation, recrystallised grain size and grain growth. Some of the most important theoretic basic approaches to describe the kinetics of primary recrystallisation were first independently developed and comprehensive portrayed by Johnson and Mehl, Avrami as by Kolmogorov (Often named the JMAK-theory).The quantitative determination of the effects of these variables obtained, analysed and compared in the context of the recrystallisation kinetics of this material.The predicted results are in good agreement with measured of laboratory tests. The results of constitutive models based on semi empirical equations will be compared in the next publication to more sophisticated models based on cellular automata, vertex and Monte-Carlo-Potts methods.Voir les détails

Mots clés : ferritic stainless steel, hot rolling, Static recrystallisation, Mathematical model.

Comportement structural et mécanique dessoudures en aciers inoxydables austénitique etduplex réalisées par le procédé TIG

A.KELLAI, A. Boutaghane, B. Boussiala, S. Kahla, S. Dehimi (2015)
Article de journal

L’objet de cette étude étant de connaître lesdifférentes variations structurales et mécaniques après un cyclethermique de soudage de deux aciers inoxydables de hauteperformance (austénitique AISI 316L et duplex AISI 2205), quisont très utilisés dans tous les secteurs, particulièrementl’industrie pétrolière. On a utilisé le procédé TIG, c’est unprocédé à arc électrique, caractérisé par son apport thermiqueintense et précis aisément automatisé, l’état microstructurale desassemblages soudés a été analysées par des observationsmétallographique optique de différentes zones à savoir : la zonefondue ZF, la zone affectée thermiquement ZAT et le métal debase MB. Finalement les changements microstructurales ont étéargumentés par une filiation de micro-dureté.Voir les détails

Mots clés : Acier inoxydable austénitique, duplex, soudage TIG, micro-dureté et contrôle


Khédidja BOUHAMLA, Hichem MAOUCHE, Abdelkader KHETTACHE, Salah Eddine BOUTEBBA (2017)
Article de conférence

Grinding balls efficiency is an important goal to reach. Forged and cast balls are widely used as raw material grinding media in several industrial areas. They are used by various raw material preparation fields. A search for a better service life is a goal most desired by all manufacturers. To improve the performance and increase the service life of ball mill grinding, various approaches have been used among which addition of alloying elements, the use of appropriate heat treatment or the change in manufacturing process. Since grinding balls are subjected to extreme abrasive and impact conditions; heat treatment must promote the desired properties. The scope of this work is to study the effect of heat treatment on the wear behavior of steel forged balls. Samples of law alloyed carbon steel were austenitized at different temperatures and are subsequently tempered at 250ºC then cooled in water. Samples were observed by optical and SEM microscopy. Hardness and friction tests were measured on all the samples. The obtained results showed the effect of the temperature austenitization variation on wear behavior and hardness values of the studied forged steel balls.Voir les détails

Mots clés : Steel forging, grinding balls, microstructure, heat treatment