Browsing by Author "Bezzazi, Boudjema"

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Alkali treatment effect on physicochemical and tensile properties of date palm rachis fibers
(Taylor & Francis, 2020) Bezazi, Abderrezak; Boumediri, Haithem; Garcia del Pino, Gilberto; Bezzazi, Boudjema
This work aims to optimize the physicochemical and tensile properties of vascular fibers extracted from a local date palm rachis in Algeria. This fiber has a very specific composition and architecture and is different from the remaining fibers obtained from the six possible parts of the tree. For this purpose, a Taguchi orthogonal array design L16 was applied to reduce the number of experiments. The ﬁbers were extracted from the rachis with two different methods (boiling and retting in water) and treated by NaOH with various concentrations (1%, 2%, 3%, and 5%) and for different durations (1, 4, 8, and 12 h). They were characterized using SEM-EDX, ATR-FTIR, XRD, and TGA to understand the effects of the extraction method and alkali treatment. A statistical treatment of the data was carried out based on the S/N ratio and ANOVA was performed to identify the most significant parameters affecting the tensile strength and the Young’s modulus of the fibers. A desirability function was developed to identify the optimal factors leading to the maximization of the tensile properties
Aspect toxicologique et physicochimique du 1,5-dipentanal
(European Scientific Institute, 2014) Bouzid, Mohammed; Bezzazi, Boudjema; Djadi, Amina; Ait Amar, Hamid; Ghouini, Ahmed
Le 1,5-dipentanal est une molécule organique importante: sur le plan pédagogique, la molécule offre un éventail de réactions chimiques intéressantes (Aldolisation, Michael, glycolyse, Cannizzaro, Mannich…). Elle présente de même des mécanismes réactionnels pour l’enseignement des fondements de l’éco-toxicologie en particulier et de la chimie dans l’environnement en général. L’étendu de ces applications entre les disciplines fines (sciences médicales, pharmaco chimie, technologie de l’enzyme, technologie des membranes biologiques et des tissus, cytochimie, histochimie, immunochimie, microscopie, RX…) engendre un abord multidisciplinaire riche d’enseignement. Le glutaraldéhyde réagit avec les protéines, les sucres, et les lipides dotés de groupements (–NH2) libre. Le groupe amine (-NH2) nucléophile réagit avec le carbonyle de la fonction aldéhyde électrophile (- CHO). Les conséquences de ce mécanisme in vivo sont au coeur d’enjeux physiopathologiques importants (le diabète, les insuffisances rénales, …). Par ailleurs, la miscibilité à l’eau (100 %), réactivité élevée dans les conditions physiologiques, hautement évaporables (contamination de l’air), intermédiaire réactionnel en industrie et un impératif pour toute désinfection et stérilisation de matériel. Le bon compromis entre avantage et inconvénient imposent une gestion réglementée de la molécule comme effluent ou résidu. Elle ne peut être rejetée dans l’assainissement, ni dans le mitan naturel. La mise au point de procédés demandée par l’intérêt pratique de la molécule et sa gestion comme déchet liquide nocif est nécessaire
Assessment of friction stir welding joints of aa2017-t4 aluminum by disc pressure mechanical tests
(2023) Djili, Abderrahmane; Bezzazi, Boudjema; Haboussi, Mohamed; Zioui, Nadjet
Precipitation hardening aluminium alloy sheets AA2017-T4 are welded by FSW on a conventional FSW tool. A macrograph of the cross section of the butt-welded joint shows the classical zones for such welding, namely the nugget zone, the thermo-mechanically affected zone and the heat affected zone. Scanning Electron Microscopy displays a grain refining and a re-formation of the precipitates in the nugget zone. Micro-hardness measurements on the cross-section perpendicular to the welding direction give the standard W-profile of the hardness for such welding, with as expected, the relatively highest value at the joint center (nugget zone). To assess the mechanical performance of the FSW welded joint, the Disk Pressure Test (DPT) is used. It shows a failure pressure for the welded specimen that is 17% lower than the base material. The fracture surface micrographs clearly show a thickness reduction at break that is ~36% higher for the base material than the welding joint and a ductile fracture mode for both specimens.
Characterization of the interface of a Non-Ferrous dissimilar realized by rotary friction welding
(Springer, 2021) Mebtouche, A.; Bezzazi, Boudjema; Ramou, N.; Aboudi, D.; Faci, Y.; Latef, M.
The need for assembly between dissimilar materials often arises in complex industrial applications. It avoids problems inherent in conventional welding. Therefore, in this study the performance of welded joints developed using a rotary friction welding machine, between Cu/Al, are characterized. The interface of the welded assembly of dissimilar copper Cua1 and AA2014 aluminum, consists of several intermetallic compounds mainly CuAl2, CuAl and Cu9Al4. Dendrites have been revealed, this structure is known to be the result of solidification. While rotary friction welding is done at the solid state. In this work, we seek to know the phenomena that take place during the entire process and in the creation of the interface. This article presents the study of the Al/Cu interfacial structure of welded joints made by rotary friction in a modified cycle with two steps
Complex di-hydrate calcium phosphate - glutaraldehyde : formulation mechanism
(2015) Bouzid, Mohammed; Djadi, Amina; Bezzazi, Boudjema
The di-hydrate calcium phosphate CaHPO4, H2O (DCPD) reacts with glutaraldehyde OCH – (CH2)3 – CHO (GL) in an aqueous solution to give the complex OCH – (CH2)3 – CH(OH) – O – PO3Ca (DCPD-GL). In the solution, the complex appears in the form of hydrates (enolic stabilized by intramolecular isomery d, e, f and as the corresponding carboxylic acid g). In the solid state it is the enolic form wich dominates (cis and trans)
Composite Cross-Ply Laminates Stacking Sequence Effect on Post Flexural Fatigue Residual Strength
(Springer link, 2021) Bezazi, Abderrezak; El Mahi, Abderrahim; Bezzazi, Boudjema; Del Pino, Gilberto Garcia; Scarpa, Fabrizio
This paper concerns an experimental approach to the stacking sequence influence on cross-ply laminates behaviour. Effects of fatigue on the residual strength and stiffness are investigated through performing post fatigue static test after specific numbers of cycles. Residual strengths were measured by testing specimens to a certain number of cycles then static tests to rupture were performed after the specimen had been unloaded without being removed. The results obtained indicate that as well as there is a drop in the specimen’s stiffness, there is a drop in the strength of the laminate as the number of cycle increases. However, this is also accompanied by an increase in the displacement mainly at higher number of cycles. The hysteresis loops revealed that a significant decrease in the maximum fatigue load was occurring as the number of cycles increased. It is also noted that the slope of the hysteresis loops decreased with respect to the number of cycles. However, a less significant drop in the minimum fatigue load than the maximum fatigue one was also observed
Effect of Alternating Hybridisation of Fibres on the Physico - Mechanical Behaviour of Composite Materials
(Sciendo, 2023) Harb, Noura; Dilmi, Hamid; Bezzazi, Boudjema; Hamitouche, Kahina
The performance/weight ratio of fiber reinforced polymer matrix composites makes them the material of choice for structural applications in many fields such as aerospace, aeronautics, automotive and civil engineering...etc. In polymer matrix composites, the fibers used as reinforcement are mainly synthetic fibers such as carbon and/or glass fibers. To ensure the low cost of using fiber- reinforced materials in motor vehicles, it is proposed to selectively incorporate carbon fibers to enhance glass fiber composites along the roadway, and to enhance glass fiber composites along the main load path. For this purpose, we conducted a behavioral study of hybrid epoxy thermoset polymer matrix laminates to highlight the influence of alternate hybridization of glass and carbon fibers on the physical- mechanical behavior of the materials.The results obtained show that the alternated hybridation of the fibers has a significant influence on the tensile properties ; and it affected the density, hardness and flexural properties significantly.
Effect of natural aging on the tensile properties and the toughness of friction stir welds of 2024-T3 aluminum alloy
(Elsevier, 2023) Djili, Abderrahmane; Bezzazi, Boudjema; Zioui, Nadjet; Haboussi, Mohamed
During friction stir welding of metallic alloys, four different microstructure zones are formed in the weld, resulting in heterogeneous mechanical properties in this latter. In the case of aluminum alloys, these properties are bound to change with aging, whether natural or artificial. In this study, changes in the toughness and tensile behavior of friction stir welds in Al 2024-T3 alloy over time are investigated. Only specimens found to be defect free, by X-ray imaging, are tested. Characterized by the area under the stress-strain curve of the material, the toughness is found to be 19% lower after 24 months of natural aging. This decrease in toughness is mainly due to a loss of ductility as the elongation of the material drops by 27% while the ultimate tensile strength increases by 9%. The fracture zone and pattern remain the same for both natural aged and freshly welded specimens. These results can be used to estimate the service life of structures using such a material, as in aeronautics.
Elaboration and characterization of composite material based on epoxy resin and clay fillers
(Universidad Nacional Autónoma de México (UNAM), 2017) Laouchedi, Dalila; Bezzazi, Boudjema; Aribi, Chouaib
The present work aims at investigating the effect of locally produced clay (Algeria), along with the effect of their size and rate on physical and mechanical properties of the composite material. This study is divided into two parts: The first one is devoted to the study of the composite material based on epoxy resin with kaolin, using different size fractions at rates ranging from 2% to 20%. The second part examines epoxy resin-based composite with calcined kaolin (metakaolin) with regard to the influence of the structure, the particle size and the charge rate on the properties of the material. It is shown that the clay fillers give the epoxy resin different properties compared to the epoxy resin alone and, additionally, reduce the cost of materials. It was also observed that the fillers enhance the mechanical properties by increasing the rigidity of the material. There is a maximum value of 2.4 GPa to 18% kaolin, or more than 325% increase in the modulus of elasticity with respect to unfilled resin for the finer particle size. It was also found that the modulus of elasticity increases with increasing the loading rate. Indeed, the rigidity increases with increasing the filler rate. Moreover, for both fillers, lower fraction yields better results. Moreover, for both types of added fillers, lower fraction yields better results
Elaboration Et Caractérisation Mécanique Quasi Statique D'un Composite Stratifie Jute/polyester
(Université M'Hamed Bougara Boumerdes, 2014) Belkacemi, Cherifa; Bezzazi, Boudjema
Les matériaux composites renforcés par des fibres végétales sont en cours de développement, leurs applications sont encore limitées mais ils sont amenés à jouer un rôle dans l’industrie future. Parmi les fibres naturelles, se trouvent les fibres végétales, matériaux de qualité, qui se fabriquent et se recyclent naturellement sur terre depuis très longtemps (matériaux biodégradables et renouvelables par culture (jute). Dans le but d’avoir un matériau le moins coûteux possible et le plus performant se qu’en intéresse à la caractérisation d’un nouveau matériau composite de type stratifié à matrice de résine polyester et renfort naturel (jute).Ce matériau composite est destiné à être utilisé dans les domaines de la construction et du transport. A l’heure actuelle, un certain nombre d’équipes de chercheurs caractérisent plusieurs types de fibres naturelles afin de faciliter leur introduction dans les matrices thermodurcissables pour la fabrication des matériaux composites. Avant l’élaboration des stratifiées nous avons caractérisé le jute par l’essai de traction après nous avons élaboré ces stratifiées sous vide, ces derniers sont découpées selon les normes.
Etude expérimentale du comportement diélectrique et thermique des nano composites hybrides à matrice époxyde chargée
(2014) Irekti, Amar; Bezzazi, Boudjema; Aribi, Chouaib; Zibouche, Fatima
Experimental study of dielectric properties of composite materials pozzolan/DGEBA
(2015) Irekti, Amar; Bezzazi, Boudjema; Smith, Agnès; Aribi, Chouaib
The fatigue flexural behavior of fiber reinforced concrete : effect of the parameters of coarse aggregates
(Academic Journals, 2015) Dilmi, Hamid; Aribi, C.; Safi, Brahim; Bezzazi, Boudjema; Saidi, M.
The effect of the coarse aggregate type on the fatigue flexural behavior of concrete was investigated in this work. Three types of the coarse aggregates were selected from three different careers (CA1, CA2 and CA3). The mechanical parameters of these aggregates were determined (Los Anglos and Micro Deval). Prismatic specimens (70×70×280 mm) for each concrete mixture were made with aggregates of each source. The flexural fatigue tests were conducted on these concrete samples with varying levels of loading of 55 to 80% and the ultimate flexural strength. The test frequency is around 80 Hz and it is automatically determined by pulsing the fatigue machine for a resonance situation (the phase shift is δ=0) between the mass-spring-specimen system. The obtained results show that the aggregates which have the similar parameters (Micro Deval and LA), provide better adhesion with cement paste, and therefore a greater bending strength. The strength evolution at short-term age is typical for specimens based on aggregates with low wear resistance by triturate (a high Micro Deval coefficient). Regarding the fatigue flexural behavior, the concrete specimens based on CA1, which have similar coefficients of Los Angeles and Micro Deval (respectively 18 and 16) present the behavior (load/cycle numbers) close to that of the model prototype of the Wöhler curve. This can be explained by a high homogeneity of the charge distribution during fatigue test compared to other concrete mixtures. Also, it was noted that the relationship between the endurance limit and the coefficient of Los Angeles is inversely proportional: The aggregates which have good strength to fragmentation (low coefficient of LA), as aggregates CA2 case give an endurance limit at around 70% max bending load
Flexural fatigue failure of concrete reinforced with smooth and mixing hooked-end steel fibers
(Cogent OA, 2019) Saoudi, Nacira; Bezzazi, Boudjema
This paper presents an experimental study on flexural fatigue dynamic behavior of reinforced concrete. Steel fiber is used for the retrofitting and strengthening flexural members, by mixing short smooth steel fiber and hooked- end fiber. By using Vibrophore HFP 150, dynamic loading was scanned at a reso- nance frequency of 100 Hz. Our objective is to examine the behavior of a specimen of 7 × 7 × 28 by a three-point bending test under high-level stress until it fails. Important research has been conducted to investigate the static and fatigue behavior of reinforcement. It was strengthened initially using one fiber, then using other additives. However, this research is not adequate to examine the flexural fatigue behavior of specimens by mixing different shaped fibers at different per- centages. A further improvement in composite concrete performance is observed by mixing two steel fibers under high-level stress. The results are in alignment with the fatigue life data using Weibull distribution.
Flexural fatigue failure of concrete reinforced with smooth and mixing hooked-end steel fibers
(Cogent, 2019) Saoudi, Nacira; Bezzazi, Boudjema
�This paper presents an experimental study on flexural fatigue dynamic behavior of reinforced concrete. Steel fiber is used for the retrofitting and strengthening flexural members, by mixing short smooth steel fiber and hookedend fiber. By using Vibrophore HFP 150, dynamic loading was scanned at a resonance frequency of 100 Hz. Our objective is to examine the behavior of a specimen of 7 × 7 × 28 by a three-point bending test under high-level stress until it fails. Important research has been conducted to investigate the static and fatigue behavior of reinforcement. It was strengthened initially using one fiber, then using other additives. However, this research is not adequate to examine the flexural fatigue behavior of specimens by mixing different shaped fibers at different percentages. A further improvement in composite concrete performance is observed by mixing two steel fibers under high-level stress. The results are in alignment with the fatigue life data using Weibull distribution.
FTIR analysis and rheological behavior of bisphenol : a diglycidyl ether resin filled Fume-Silica
(2014) Irekti, Amar; Bezzazi, Boudjema; Boualam, Chahrazed; Aribi, Chouaib; Dilmi, Hamid
Silica-fume as fillers into polymers materials affect significantly the physical, mechanical and the electrical properties of the polymers. The polymer that we studied here is an epoxy based resin (STR) and silica fume (FS). This paper presents the dependency of the rheological behavior of the STR epoxy resin on the FS content within a temperature at which the reaction thermoset is neglected. We used a cone-plate viscometer for the study of the rheological behavior, and a scanning electron microscope is used for the analysis of the dispersion state of the FS in STR epoxy resin. Compared to the control without loads, an increase of 50% of the shear stress and the plastic viscosity were recorded for the composite. The software Rheowine viscometer enabled us to model and identified the rheological behavior of these mixtures with resin. The results obtained in this modeling, confirmed that the resin mixtures have shear-thinning rheological behavior, this last give us the model of Ostwald de Waele
IVème Séminaire National Matériaux, Procédés et Environnement FSI, Boumerdès 15 & 16 Mai 2012
(Unité de Recherche Matériaux, Procédés et Environnement (UR-MPE) Université M’Hamed Bougara Boumerdès, 2012) Bezzazi, Boudjema
Mechanical alloying of the fe-cr mixture and stabilization of the sintered nanostructure by carbon addition
(Politechnica University of Bucharest, 2021) Amirouche, Saïfi; Bezzazi, Boudjema; Nechiche, Mustapha; Azem, Said
The present work concerns the mechanical alloying of the iron-chromium mixture (Fe20% Cr) and the evolution of the crystallite size before and after sintering at high temperature. A study was conducted on the stability of the nanostructure of the sintered material. The effect of adding carbon on the structure and the crystallite size was studied for the sintered material. The X-ray diffraction technique was used to identify the new phases and measure the crystallite size as well as the microstrains induced by mechanical alloying. Scanning electron microscopy revealed structural changes in the milled and sintered material
Mechanical behavior of multilayered sandwich panels of wood veneer and a core of cork agglomerates
(Elsevier, 2014) Lakreb, Nadia; Bezzazi, Boudjema; Pereira, Helena
Mechanical strength properties of innovative sandwich panels with expanded cork agglomerates
(Springer, 2015) Lakreb, Nadia; Bezzazi, Boudjema; Pereira, Helena