Publications Scientifiques
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Item Synthesis of resin from Alfa stem to applied as an adhesive corrosion-resistant coating(Springer Nature link, 2025) Toubal, Sara; Aribi, Chouaib; Chentir, Imen; Safi, Brahim; Bouaissi, Aissa; Saidi, MohammedThe demand for eco-friendly alternatives to petrochemical-based phenolic resins has risen due to increasing concerns about climate change, environmental impact, and manufacturing costs. This study introduces a sustainable approach by partially replacing phenol with lignin, a natural polymer rich in phenolic groups, extracted from Alfa stems. Using the alkaline method, 50% of phenol was substituted with lignin to synthesize phenol–formaldehyde (PF) resins. The synthesized lignin–phenol– formaldehyde (LPF) resin was characterized to verify its chemical structure and physical properties. The resin demonstrated significant antioxidant and antibacterial activity, particularly against E. coli and P. aeruginosa gram-negative bacteria at a concentration of 20 mg/ml. Additionally, the lignin substitution provided notable advantages over conventional industrial resin formulations. The lignin’s properties closely influenced the formulation of the LPF resin, making it similar to the reference CPF resin. However, the lower intensity observed in the LPF resin suggests potential limitations in the methylol group formation compared to the CPF resin. The antioxidant activity of LPF resin has been effectiveness in preventing cor- rosion on steel surfaces. When applied as an anti-corrosion coating and compared to industrially used CPF resins, LPF resin demonstrates its efficacy in such applications. Also, it should be noted that the impedance modulus of the elaborated resin coating remained consistently low throughout the entire immersion period, indicating its stable performance.Item Mechanical characterization and impact resistance of a novel hybrid composite based on salvadora persica roots and glass fibers(University of Zielona Gora, 2024) Chetouh, Samir; Ameur, Toufik; Bouakba, Mustapha; Gaagaia, Djamel Edinne; Khalfi, M.; Safi, BrahimThe observation of fibers in salvadora persica roots inspired us to consider the idea of using them as reinforcement to create an innovative composite. The current work focuses on the volumetric mass density, extraction, molding, and mechanical testing of composites and hybrid composites made from salvadora persica roots and glass fibers reinforced with two types of polyester matrix, chosen due their characteristics suitable for use in different orientations. Various extraction and combination methods have been used to identify an optimal approach for obtaining fibers from salvadora persica roots, considering its chemical composition (hemicellulose, pectin, and lignin). In this investigation, the hand lay-up method was used to mold specimens with different geometries. The composite and hybrid composite were combined with a polyester matrix and subjected to various mechanical tests namely; tensile, impact resistance, and water absorption. The results indicate that reinforcing polyester resins with SP fibers, whether long or short, enhances the overall mechanical properties of the composite. Additionally, improved adhesion between salvadora persica roots fibers and resin was observed.Item Evaluation of Viscoelastic Performance and Molecular Structures of Natural Rubber/NBR Blends Reinforced by Carbon Black and Nano-Silica(Periodica Polytechnica, 2024) Chelli, Amel; Mechakra, Hamza; Chellil, Ahmed; Tria, Djalel Eddine; Bessa, Wissam; Ikkache, Kamel; Safi, BrahimThis study focuses on the evaluation of the dynamic mechanical properties, molecular structure, density, hardness, swelling behavior of natural rubber blends (NR) and nitrile rubber (NBR) reinforced with carbon black and/or nano-silica. An experimental work has been conducted to study of the effects of increasing NR content and incorporating nano-silica on the mechanical properties and molecular structure were studied using dynamic mechanical analysis (DMA) and Fourier transform infrared (FTIR) spectroscopy. The results show that increasing the NR content and/or incorporating nano-silica into the elastomer leads to a higher storage modulus with no significant change in the glass transition temperature. FTIR analysis indicates the compatibility of the polyblends and the presence of oxidation of the main polymer chain generated during the grinding of the rubber. Additionally, the results of the swelling study demonstrate that stronger molecular interactions occur on the surface of the nano-silica between the nitrile radicals in the NBR and the silanol (Si-OH) radicals. These findings suggest that blending NR and NBR with carbon black and/or nano-silica can improve the mechanical properties and compatibility of the resulting polyblends, with potential applications in the development of advanced elastomeric materials.Item RHEOLOGICAL AND MECHANICAL BEHAVIOR STUDY OF ECO-FRIENDLY CEMENT MORTAR MADE WITH MARBLE POWDER(University of Zielona Gora, 2024) Chahour, Kahina; Mechakra, Hamza; Safi, Brahim; Dehbi, Nacera-Melissa; Chaibet, CyliaThe work aim is to investigate the rheological and mechanical behavior of an eco-friendly mortar made with marble powder. Marble is have used as sand (total substitution of natural sand) and as an additional material (partial substitution of cement). Firstly, rheological tests were carried out on the cement pastes in order to study the effect of cement substitution by marble powder on the rheological behavior. Secondly, our study is devoted to evaluate the mechanical performances (flexural strength, compressive strength, mechanical behavior and ultrasonic pulse velocity) of a fluid mortar such as the case of the self-compacting mortars elaborated with the marble powder as an addition a material and as sand. The mechanical test results show that compressive strength and mechanical behavior of an ecological cement mortar made with marble waste as natural sand improved significantly. However, marble-based mortars with 100% of marble sand have given a mechanical strength similar to that obtained by control cement mortar (100% natural sand). It was also noted that it an ecological cement mortar made with 30% of marble powder as an addition a supplementary material can be obtained. This leads to a reduction in cement consumption and a reduction in CO2 gas emissions caused by cement production.Item Assessing the Utilization of Sawdust in Water-Based Drilling Fluid for Managing Fluid Loss and Enhancing Viscosity(Taylor & Francis, 2024) Ysbaa, Saadia; Safi, Brahim; Sid, Asma Nour El Houda; Mhadhbi, Mohsen; Essafi, WafaThe evaluation of the use of sawdust in drilling fluid formulation is covered in this study. The investigation focused on the physicochemical and rheological properties of water-based mud (WBM) drilling fluids that included four different dosages of sawdust. These properties included yield stress, plastic viscosity, rheological behavior, gel strength, filtration test (API filtrate; American Petroleum Institute), and pH. The sawdust was employed as a substitute for the polymers commonly used in water-based muds (WBMs) to serve either as a viscosifier or as a fluid loss controller. The current study set out to evaluate how sawdust (diameter ≤630 µm) affected the primary characteristics of the drilling muds. Sawdust was utilized in place of carboxymethyl cellulose polymer (CMC) as a viscosifier and polyanionic cellulose polymer (PAC) as a filtrate reducer at several dosages (0, 10, 20, 50, and 100 g/L). It was found that the sawdust dosage and its role had a significant impact on the rheological characteristics of the drilling fluids. At amounts between 20 and 50 g/L, the sawdust was added as a viscosifier to the drilling fluids under study, resulting in a significant improvement in their physicochemical and rheological parameters (yield stress, plastic viscosity, and gel strength). However, the drilling fluids showed extremely high rheological properties and a viscosity that can slow down fluid circulation in the well when 100 g/L of sawdust were used, totally substituting for the polymers.Item Crack growth diagnostic of ball bearing using vibration analysis(Sciendo, 2022) Belaid, S.; Lecheb, Samir; Chelil, A.; Mechakra, H.; Safi, Brahim; Kebir, H.It is known that supported ball bearings have great effects on the vibrations of the gear transmission system, above in all the presence of local faults as well as the crack growths. For this purpose, this paper focuses on shock and vibration crack growth diagnostic of ball bearing using vibration analysis. Our work is devoted first to a study the static behaviour of the ball bearing by determining the stress, strain and displacement, then its dynamic behaviour by determining the first four natural frequencies. Secondly, a dynamic analysis study of the bearing was carried with defects as a function of crack size and location. The obtained results clearly show that the natural frequencies decrease in a non-linear way with the growth of the length of the crack, on the other hand the stress increases with the presence of the singular points of the crack. Finally, this residual decrease in natural frequencies can be used as an indicator of the state of failure, as well as a parameter used for the diagnosis and screening, and to highlight the fatigue life of the bearingItem Annealing effect on copper-doped sodo-borate glasses (na2o-4b2o3)(2023) Aboutaleb, Djamila; Safi, BrahimThe annealing effect of an alkalino-borate type glass below the softening temperature was investigated accord ing to the Na2O-B2O3 binary system. Doping of the samples was done by the introduction of copper oxide "CuO" according to different levels. The properties of elaborate glasses before and after annealing have been studied. DRX diffraction, optical spectroscopy and infrared analysis were used to complete this study. The obtained results show that the annealing heat treatment affects the structure of these glasses by redistributing the structural units, partially correcting the defects and reinforcing them of the structure. It has been noticed that the BO3 units are reformed again and the BO4 have decreased, which has led to an increase in the coefficient of thermal expansion, a decrease in the diffraction index and optical dispersion, a drop in mechanical prop erties, thermal conductivity and electrical permittivity.Item Effect of metakaolin as partially cement replacement on the compressive strength of standard mortars(2021) Amrane, Belaid; Souici, Khaled; Hami, Brahim; Kennouche, Salim; Safi, BrahimThis study presents the effect of incorporating synthesized metakaolin on the compressive strength of standard mortars for a constant water/binder ratio of 0.5. Synthesized metakaolin mixtures with cement replacement of 5, 10, 15 and 20% were tested. From the results, it was observed that 15 % replacement level was the optimum level in terms of compressive strength. Beyond 15 % replacement levels, the strength was decreased but remained higher than the control mixture. Compressive strength of 52 MPa was achieved at 15 % replacement. This investigation has shown that it is possible to produce high strength mortars using local kaolin.Item An ecological water‑based drilling mud (WBM) with low cost: substitution of polymers by wood wastes(Springer, 2019) Haider, Soumia; Messaoud‑Boureghda, Mohamed‑Zine; Aknouche, Hamid; Akkouche, Ali; Hammadi, Larbi; Safi, BrahimAn ecologically friendly water-based drilling mud (WBM) was designed by using wood wastes (WP: wood powder) in order to substitute the organic polymers which are very expensive and often make the higher cost of the oil well drilling. This present work is dedicated on studying the rheological behavior and main rheological properties of WBM containing the wood powder at different contents and sizes by substitution of usually used polymers. The effect of wood powder on the drilling fluid filtrate was also analyzed. The drilling fluid that was developed has better rheological properties and fluid loss control which are required for a good functioning of oil well drilling. By a total substitution of polymers, the wood powder (300 μm at 850 kg/m3) can be used as a filtrate reducer of mud because the WBM filtrate obtained exhibits a minimum and having requested values for such formationItem Influence of superplasticizer doped by Nano-silica on the rheological and mechanical properties of cement mortars(2019) Daoui, Abdelhakim; Safi, Brahim; Zerizer, AbdellatifPrevious research indicates that the inclusion of nanosilica (NS) modifies the properties of the fresh and hardened state, compared to the traditional mineral additions. Some authors estimate that the appropriate percentage of Nano-silica should be small because of difficulties caused by agglomeration to particles during mixing, while others indicate that 10% by weight, if adjustments are made to the formulation to avoid an excess of self-drying and micro cracks that could impede strength. For this purpose, the present work aim to see the effect of the introduction mode of the nanosilica on the rheological and physic mechanical properties of cement mortars. In this study, NS was used either powdered with cement or in solution with the superplasticizer (Superplasticizer doped in nanosilicafigure (a)). Results show that the use of nanosilica powder (replacing cement on the one hand) has a negative influence on the rheological parameters and the rheological behavior of cementitious pastes. However, the introduction of nanosilica in solution in thesuperplasticizer (SP) was significantly improved the rheological parameters and the rheological behavior of cementitious pastes. Indeed, more the dosage of NS-doped SP increases more the shear stress and viscosities of the cementitious pastes become more fluid and manageable. A significant reduction of shear stress and plastic viscosity were observed that due to the increase in superplasticizer. A dosage of 1.5% NS-doped SP gave adequate fluidity and the shear rate was lower.