Browse
Recent Submissions
Item Ge(Sn) growth on Si(001) by magnetron sputtering(Materials Today Communications, 2020-11-26) BENOUDIA Mohamed Cherif (Co-Auteur)The semi-conductor Ge1–xSnx exhibits interesting properties for optoelectronic applications. In particular, Ge1–xSnx alloys with x ≥ 0.1 exhibit a direct band-gap, and integrated in complementary-metal-oxide semiconductor (CMOS) technology, should allow the development of Si photonics. CMOS-compatible magne tron sputtering deposition was shown to produce monocrystalline Ge1–xSnx films with good electrical properties at low cost. However, these layers were grown at low temperature (< 430 K) and contained less than 6 % of Sn. In this work, Ge1–xSnx thin films were elaborated at higher temperature (> 600 K) on Si(001) by magnetron sputtering in order to produce low-cost and CMOS-compatible relaxed pseudo-coherent layers with x ≥ 0.1 exhibiting a better crystallinity. Ge1–xSnx crystallization and Ge1–xSnx crystal growth were investigated. Crys tallization of an amorphous Ge1–xSnx layer deposited on Si(001) or Ge(001) grown on Si(001) leads to the growth of polycrystalline films. Furthermore, the competition between Ge/Sn phase separation and Ge1–xSnx growth prevents the formation of large-grain Sn-rich Ge1–xSnx layers without the formation of β-Sn islands on the layer surface, due to significant atomic redistribution kinetics at the crystallization temperature (T = 733 K for x = 0.17). However, the growth at T = 633 K of a highly-relaxed pseudo-coherent Ge0.9Sn0.1 film with low impurity concentrations (< 2 × 1019 at cm–3 ) and an electrical resistivity four orders of magnitude smaller than undoped Ge is demonstrated. Consequently, magnetron sputtering appears as an interesting technique for the integration of optoelectronic and photonic devices based on Ge1–xSnx layers in the CMOS technology.Item Remove of a mixture cationics dyes in aqueous solution by a green emulsion liquid membrane(Global NEST Journal, 2025-01-16) BENDEBANE Salima (Co-Auteur)The objective of this work is the treatment and purification of an aqueous solution loaded with a mixture of dyes, malachite green (MG) and rhodamine B (Rh-B) using a green emulsified membrane GELM. The proposed GELM process consists of a surfactant (Span 80), an internal phase (sulfuric acid) and a diluent (soybean oil). A Box-Behnken design was implemented to optimize the operating parameters. Three factors were varied: the mass percentage of Span 80, the concentration of the internal phase and a volume ratio Vext/Vem, while keeping the other parameters constant. The results of the optimization give an extraction yield of the dye mixture of 99.77% under the following optimum conditions: 10% by mass for Span 80, a concentration of 0.5 M for the internal phase and a Vext/Vem volume ratio of 7.Item Elimination of malachite green by modified Fenton like process. Application of Box Behnken design(Global NEST Journal, 2024-10-16) BENDEBANE SalimaThe aim of this work was to investigate an advanced oxidation process for removing malachite green from aqueous solutions using a modified Fenton-like process. An experimental Box-Behnken design was applied to determine the optimal conditions by examining the effects of catalyst concentration ([Fe2+]), oxidant concentration ([K2S2O8]), and stirring speed. The analysis of variance (ANOVA) indicated that oxidant concentration was the most significant factor, with a p-value of 0.001, while catalyst concentration, the quadratic term of the oxidant, and the interaction between catalyst concentration and stirring speed were also significant. The optimal conditions for maximum dye removal were found to be a catalyst concentration of 3.5 ppm, an oxidant concentration of 3.07 ppm, and a stirring speed of 200 rpm, achieving a theoretical degradation yield of 100% and an experimental yield of 98%. This agreement validates the model and the importance of the optimized parameters. Additionally, degradation kinetics studies in various natural waters revealed that oxidation efficiency followed this order: Distilled water (98%) > Seawater ≈ Industrial water (88.97%) > Source water (85.57%) > Mineral water (80.52%).Item For a Sustainable Management of Potential Impacts of Global Change on Coastal Aquifers: Case Study of Coastal Aquifers in Annaba City, Algeria(Polish Journal of Environmental Studies, 2024-07-13) AICHOURI Imen; NETTOUR Djamel (Co-Auteur)The Annaba region, situated in the northeastern part of Algeria, harbors significant groundwater resources vital for supplying water to the population, agriculture, and industry. However, increasing pressures from heavy water depletion are raising serious concerns. Continuous exploitation of the aquifer has led to deteriorating water quality and adverse effects on its hydrodynamic equilibrium, resulting in saline intrusions that threaten aquifer utilization and wetland functionality. This study aims to investigate the mechanisms of marine intrusion to characterize saline pollution, identifying the key factors and solutions for seawater contamination of aquifers. Projections for 2035, assuming current climatic conditions and exploitation practices, indicate that without intervention, the negative impacts on groundwater and ecosystems could become catastrophic. The saline intrusion is expected to advance inland by 200 to 300 m on the eastern edge, 500 m in the center of the plain, and up to 1500 m further west. Numerical simulation models, considering environmental heterogeneity, have proven highly effective for understanding the hydrodynamic behavior of aquifers. These models also highlight the vulnerability of coastal aquifers to seawater inflows and significant chloride concentration fluxes. To address the urgent problem of increasing water scarcity in Algeria’s coastal plains, several recommendations have been proposed.Item Study of the periodic thermal contact between exhaust valve and its seat in an internal combustion engine(Maintenance and Reliability, 2023) AZZOUZ Salaheddine (Co-Auteur); AYAD Amar (Co-Auteur)The focus of internal combustion engine development for urban vehicles is shifting towards reducing materials by making them lighter. In order to maintain thermal and flow levels, a model was developed to study the thermal behavior of valve seats during periodic contact, which can also help improve engine performance and fuel efficiency. The model, composed of two cylindrical bars in periodic contact, takes into account the evolution and topography of the contact surface. The model's performance was evaluated through various experimental studies and showed a maximum difference of 5.05% with experimental values, in good agreement with previous literature. The results showed that heat flux increases with increasing contact frequency and thermal diffusivity affects conductive transfer. This model can be used by manufacturers to evaluate cylinder head temperature and by the automotive industry to improve heat transfer in engines.Item A Novel Micro-Thermophotovoltaic Combustor of Hydrogen–Air to Enable Ultra-Lean Combustion, High Thermal Output and NO Low Emissions(International Journal of Energy Research, 2025-01) AZZOUZ Salaheddine (Co-Auteur)This study presents a novel micro-combustor (MC) design called micro-trapped vortex combustor (MTVC) for microthermophotovoltaic (MTPV) devices used in small-scale electricity generation. Traditional MC designs struggle to operate efficiently under ultra-lean regimes due to flame quenching, limiting their performance. The proposed MTVC incorporates the trapped vortex concept, inspired by aeronautical applications, to improve thermal performance and stability under ultra-lean conditions. Numerical simulations, using the Navier–Stokes and energy equations for laminar and reactive flow, are conducted to compare the MTVC with conventional micro-backward-step combustors (MBSCs) under hydrogen (H2)–air mixture combustion. The study focuses on key performance parameters such as temperature distribution, heat recirculation, flame shape, flow topology, radiative power and emissions. The results show that the MTVC can operate at an ultra-lean equivalence ratio of Φ=0.5, while the MBSC experiences flame quenching below Φ=0.7. The MTVC design achieves up to 26.51% higher radiative power and a 36% improvement in energy conversion efficiency compared to traditional combustor designs. Additionally, the MTVC produces 43% less nitrogen oxides (NOx) emissions, demonstrating its potential for both higher efficiency and reduced environmental impact in portable power applications.