Institutional repository of university M'Hamed Bougara Boumerdes
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Aerodynamic performance investigations of savonius twin-rotor wind turbines
No full textThe aim of this study is to evaluate the aerodynamic efficiency of a Savonius vertical-axis wind turbine. The approach used relies on resolving the Unsteady Reynolds Averaged Navier-Stokes equations (URANS), the turbulence being modeled by the k-ω SST model. The flow around the wind turbine is simulated using the arbitrary sliding interfaces technique. First, the study investigates the impact of blade shape on wind turbine efficiency by examining seven Savonius rotors constructed with distinct blade configurations. The results indicate that the highest aerodynamic performance is provided by the rotor with the elliptical blades, with a notable increase in the power coefficient of about 80% in comparison to the classic semi-circular profile. To further enhance the efficiency of the Savonius wind turbine, a twin-rotor configuration using the elliptical blades was studied. The results indicate a further enhancement in the power coefficient, reaching 110% compared to a single rotor with semicircular blades. © 2024, Isfahan University of Technology. All rights reserve
دور الصندوق الوطني للتأمينات الجتماعية للعمال االجراء في تقديم الخدمات التأمينية: دراسة حالة: تعويضات مركز الدفع – وكالة بومرداس -
No full text99p.:ill.;30cm
Influence du vieillissement sur les propriétés physiques et mécaniques de différents elastomères
No full text104 p. : ill. ; 30 cmLes effets de deux types de noir de carbone (N220 et N550), sur les caractéristiques ultimes du caoutchouc naturel (NR) ont été étudiés de manière comparative. L'étude comparative a été réalisée à l'aide d'analyses du comportement rhéométrique, le comportement mécanique telle que la résistance à l'abrasion la dureté surfacique et la résistance à la traction , Les résultats obtenus ont montré qu'il existe des taux optimaux de charges qui ont la meilleure influence sur les propriétés, dus à une meilleure dispersion et mobilité des chaînes en caoutchouc, sont la principale raison de l'amélioration des résultats. Selon ces résultats nous avons choisis deux taux de chargement 10 phr et 20 phr et un caoutchouc naturel non chargé, pour étudier le comportement au vieillissement accéléré pendant 7 jours a quatre température -15°C 0°C 50°C et 100°C respectivement .
L'objectif principal de ce travail est de développer une formule améliorée pour un composé industriel à base de caoutchouc naturel peut résister à des températures plus élevée
Calcul de vérification de la batterie d’échange «12E1» (A/B/C) au niveau de la raffinerie d’Arzew
No full text81 p. : ill. ; 30 cmLe Travail à réaliser dans le cadre de ce projet de fin d’études m’a été proposé au niveau du la raffinerie d’Arzew au terme d’un stage pratique que j’ai eu la chance d’y effectuer. Le travail en lui-même porte sur l’analyse des performances d’un échangeur de chaleur de type tube-calandre 12 E-1(A /B/C) de l’unité 12 du complexe RAIZ. Notre thème renferme une étude thermique qui consiste essentiellement à déterminer la surface d’échange thermique nécessaire et le flux thermique échangé, et une autre étude hydraulique qui fait appel à la mécanique des fluides, nécessaire pour la détermination des pertes de charges dans l’échangeur. L'objectif de notre étude est de collecter toutes les données actuelles et de conception afin de procéder à un calcul de vérification pour évaluer l'état de la batterie d'échange
Arisarum vulgare: Bridging Tradition and Science Through Phytochemical Characterization and Exploring Therapeutic Potential via In vitro, In vivo, and In silico Biological Activities
No full textArisarum vulgare O. Targ. Tozz. (Araceae), locally known as “Elbgouga,” holds significant traditional importance in Algeria for the treatment of various human ailments, including pain, infections, inflammation, digestive disorders, cancer, skin problems, eczema, wounds, and burns. The aim of this study was to explore for the first time the phytochemical profile, antioxidant, antibacterial, and inhibitory effects on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes, DNA protection, and capacity to promote wound healing. Preliminary phytochemical experiments were conducted to evaluate the major classes of bioactive compounds, in addition to the total phenol and flavonoid amounts in AVEE. An LC-MS/MS analysis was conducted to clarify the phytochemical composition of this particular botanical species. The antioxidant capacity was assessed using DPPH· and ABTS·+ radical scavenging tests. The agar diffusion approach was used to ascertain the antibacterial efficacy against four bacteria (Staphylococcus aureus, Enterococcus faecium, Escherichia coli, and Salmonella typhimurium). Cholinesterase inhibition was evaluated using a colorimetric method that relies on Ellman's reaction. The protective effects of AVEE on pBR322 plasmid DNA damaged by H2O2 and UV treatment were assessed by their DNA-breaking forms. The in vivo acute dermal toxicity and wound healing potential of the AVEE ointment (1–5% AVEO) were also investigated, and histological analyses were carried out on biological samples. Five protein targets were the subject of an in silico molecular docking investigation (TNFα, TGFBR1, IL-1ß, GSK-3ß, and NOS) and ADMET studies of the main components of the extracts were performed. The screening of phytochemicals revealed a significant concentration of phenolic compounds (176.00 ± 1.08 mg of gallic acid equivalents/g of dry extract), mainly flavonoids (81.21 ± 1.24 mg of quercetin equivalents/g of dry extract). Three major compounds were identified by LC-MS/MS analysis, belonging mainly to the class of flavonoids, with rutin as the most abundant compound (11.85 mg/g extract), followed by hesperidin (4.125 mg/g extract). A conspicuous presence of isoquercitrin (1.327 mg/g extract) was also found. Small amounts of flavonoids and phenolic acids were also detected (catechin, chlorogenic acid, syringic acid, salicylic acid, kaempferol, and luteolin). DPPH assay showed higher antioxidant capacity compared to the ABTS·+ assay (142.60 ± 5.52 µg/mL and 236.10 ± 0.22 µg/mL, respectively). AVEE was effective against all selected bacterial strains; however, the highest zone of inhibition (36.00 ± 0.1 mm) was noted against E. faecium. The extract of the plant significantly inhibited both AChE and BChE (89.98 ± 18.76 µg/mL inhibitory activity against AChE and 98.28 ± 44.68 µg/mL inhibitory activity against BChE, respectively). The ethanolic extract of A. vulgare and quercetin exhibited more significant DNA protection action in form I, with percentages of 90.41 and 94.23%, respectively, compared to form II, where the percentages were 27.91 and 51.92%, respectively. The AVEO formulation may be safely administered by topical application. A statistically significant wound contraction was discovered in the group treated with 5% AVEO compared to the groups that were not treated or treated with petroleum jelly. Furthermore, there was no notable disparity detected between the group treated with 5% AVEO and the group treated with the reference drug. The 5% AVEO-treated group showed, after the research was complete, the most significant percentage of wound contraction (96.90 ± 0.42%). Moreover, the topical application of the formulation improved histological parameters. In silico study showed that rutin, hesperidin, and isoquercitrin had a high affinity to the five main targets that might contribute to the wound healing potential of A. vulgare ethanolic extract. The impressive biological capabilities of A. vulgare indicate that the plant has the ability to be a valuable source of bioactive chemicals with various medical applications
استخدام الاجنة الفائضة في ابحاث الخلايا الجذعية الجنينية (دراسة مقارنة)
No full textعن طريق استخدام الخلايا الجذعية الجنينية تمكن علماء الطب التجديدي من معالجة الكثير من الأمراض المستعصية، وهذا من خلال اجراء الأبحاث العلمية عليها من عدة مصادر، أهمها الأجنة الفائضة عن تقنيات المساعدة الطبية على الانجاب، وهذا ما خلق جدلا بين علماء الدين ورجال القانون والباحثين حول مشروعية أبحاث الخلايا الجذعية الجنينية من الاجنة الفائضة
Etude Et Conception D’un Bras Manipulateur De Soudage Coffre-fort
No full text79 p. : ill.Ce travail implique la conception et la commande d'un robot industriel, en l'occurrence un robot de soudage industriel à trois degrés de liberté.
Ce projet se compose de deux parties principales :
La première partie se concentre sur la conception et la modélisation de la structure mécanique et des actionneurs du robot.
La deuxième partie est dédiée à la commande et à l’asservissement à l'aide d'un logiciel MATLAB
High Gain and Wide Beam Printed LPDA with Improved Bandwidth Based on Multiple Scaling Factors
No full textIn this paper, a modified printed log periodic dipole array (MPLPDA) antenna based on multiple scaling factors for high gain and wide beam-width is presented. To improve the gain and broaden the beam while enhancing the impedance bandwidth, a design based on dividing the LPDA dipole elements into three groups with three scaling factors for each group is proposed. The -10 dB bandwidth of 1.36 GHz to 12.8 GHz is realized in addition to some high frequency sub bands. Furthermore a -7.3 dB bandwidth of 1.29 GHz to 18 GHz is achieved. The designed antenna is realized on F4B substrate with thickness of 1mm and a good agreement is noticed in the measurement of the input reflection coefficient and radiation patterns. The measurements show the UWB end-fire operation of the proposed LPDA with a maximum realized peak gain of 10.59 dBi. Moreover, the fabricated antenna maintains a realized gain values greater than 5 dBi and -3 dB beam-widths at both E and H plane wider than 58°in almost all L, S and C band frequencies. The proposed antenna can be used for ESM / ELINT systems by tilting it at an angle of 45°for high polarization receiving capability
Etude d’un bâtiment en béton armé contreventé par des voiles (R+6) à usage d’habitation et commercial
No full text115 p. : ill.Ce projet présente une étude détaillée d’un bâtiment à usage multiple, constitué d’un Rez-de- chaussée plus six étages(R+6), implanté à Bordje Menail Wilaya de Boumerdes. Cette région est classée en zone de sismicité moyenne (IIb) selon les règles parasismiques algériennes RPA99 version 2003. L’objectif étant le dimensionnement des différents éléments constitutifs du bâtiment et de déterminer le ferraillage approprié pour la résistance de ce dernier aux différentes actions au quelles il peut être soumis. Nous avons dû faire appel aux règlements en vigueur notamment le CBA93, le RPA99 /2003 et le BAEL91 /99. Afin de déterminer les efforts internes dans les portiques, et en dynamique pour le calcul des
modes de vibration, nous avons utilisé le logiciel de calcul ETABS V.21.0. En dernière étapes du mémoire
nous avons fait l’étude et les calculs de l’infrastructure