Faculty of exact science_PPN

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    Film Thinckness effect on Structure and Optical Properties of nanostructured ZnS thin films Deposited By spray Technique
    (University of Eloued جامعة الوادي, 2019-11-12) Ayadi, M.; Benhaoua, A.; Benramache, S.; Sebais, M.; Halimi, O.; Boudine, B.
    In this work, the sprayed ZnS thin films were deposited on glass substrate at 400C° using ultrasonic spray chemical technique (SPC). The effect of film thickness on structure and optical properties of nanostructured ZnS thin films was investigated. From XRD analysis, it was observed that the prepared material has a hexagonal structure with good crystallinity. This finding was in a good agreement with the morphological properties in the SEM images. It was also found that the maximum crystallite size is 45.3nm, which was obtainedwith577 nm film thickness. From optically experiments, ZnS thin films have a good transparency in visible region and the band gap energy of all deposit films was varied in the range 3.9-4.1eV في هدا العمل قمنا بتحضير الأغشية الرقيقة لكبريتات الزنك مرسبة على حوامل الزجاج عند درجة مئوية 400 بواسطة تقنية الرش و تمت دراسة تأثير السمك على الخواص البنيوية و الضوئية لهده الأغشية. بينت نتائج الأشعة السينيةأن المادة المحضرة ذات تبلور جيد وتملك بنية سداسية،وهده الأخيرة في توافق جيد مع نتائج الماسح الإلكتروني. و قد وجد أن الحجم الأعظمي للحبيبات هو 45.3نانو متر للعينة ذات السمك 577نانو متر. فيما يخص الدراسة الضوئية بينت النتائج أن الأغشية ذات شفافية جيدة في المجال المرئي وأن قيمة الفاصل الطاقي تتغير ما بين 3.9 و4.1
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    DNA Fragment Assembly Using a Teaching–Learning-based Optimization Algorithm
    (University of Eloued جامعة الوادي, 2019-11-05) Ben Ali, Abdelkamel
    In this work, we propose an adaptation of the novel Teaching–Learning-Based Optimization (TLBO) algorithm for assembling DNA fragments. TLBO is a population-based metaheuristic that simulates the classical school learning process. The TLBO algorithm implemented in this work operates in two stages. During the first stage (TeacherPhase), a Probabilistic Edge Recombination Crossover (PERX) operator is applied to build a new solution from three permutation vectors (orders of fragments ID): the current solution, the best individual in the population, and a mean permutation vector calculated from all individuals. During the second stage (LearnerPhase), a PERX operator is applied to the current solution and a randomly selected individual for building two new solutions. In both stages, the new solutions will be only accepted into the population if they are better than the current solution. The algorithm continues until the termination condition is met. Our simulation results on literature benchmarks show that our PERX-based TLBO algorithm, in its basic form, has a very good performance and outperforms our basic discrete PSO algorithm proposed in [1] يتمثل هذا العمل في مطابقة خوارزمية جديدة تسمى بالإنجليزية Teaching–Learning-Based Optimization (TLBO) علىمسألة تجميع قطع الحمض النووي، مسألة تحسين صعبة في مجال المعلوماتية-البيولوجية. هذه الخوارزمية مستوحاة من طريقة نشر المعرفة داخل حجرة الدراسة، حيث يكتسب التلاميذ المعرفة من معلم في البداية، ثم من زملائهم في الصف
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    CFD Study of Methane-Hydrogen Behavior in a Non-Premixed Combustion Chamber
    (University of eloued جامعة الوادي, 2017-11-26) Attia, M. E. H.; Boukhari, A.; Bouras, F.; Driss, Z.
    In this paper, the numerical results of the study of a turbulent flame of methane-hydrogen/air generated by a cylindrical burner are presented. The numerical simulations are carried out using the CFD code "FLUENT" and "Gambit" for the meshing process. The finite volume method was used to solve the Navier-Stokes equations governing the flow. The coupling of the LES/PDF models is used to model the turbulence/chemistry interaction in the system's transport equations. The results of the calculations are expressed and analyzed in terms of axial velocity, temperature and mass fraction of carbon monoxide CO. The results of the numerical calculations are compared and validated against experimental data. In addition, the same parameters considered above are used in the study of the combustion behavior of CH4 /H2 fuels. The obtained results confirm the fact of considering hydrogen as a clean nonpolluting fuel compared to methane, since it has no carbon monoxide emissions in combustion products. Besides this fact, the hydrogen gas velocity in the flame is significantly higher by comparing it to the methane gas velocity