Lydia Ounecer, Massinissa Adnani, Tinhinane Aghouiles

كلية التكنولوجيا-جامعة عبد الرحمان ميرة - بجاية · الجزائر

Dans ce travail, nous présentons une étude numérique de la convection mixte dans unecavité carrée remplis d?un nanofluide (Al2O3-eau) avec une marche (ascendante etdescendante). La paroi supérieure est maintenue à une température froide, la paroi latéraleest maintenue à une température chaude et le reste des parois sont supposéesadiabatiques .Les équations qui régissent ce phénomène ont été résolues par une approchenumérique, basée sur la méthode des volumes finis.L?étude a été réalisée pour différents nombres de Grashof, de Reynolds, différentesconcentrations du nanofluide . Les résultats obtenus montrent que le transfert de chaleur estmeilleur si la fraction volumique et le nombre de Reynolds sont augmentés.In this work, we present a numerical study of mixed convection in a square cavity filledwith a nanofluid (Al2O3-water) containing a step (upward and downward). The upper wallis maintained at a cold temperature, the side wall is maintained at a hot temperature, andthe remaining walls are assumed to be adiabatic. The governing equations for thisphenomenon have been solved using a numerical approach based on the finite volumemethod.The study was conducted for different Grashof and Reynolds numbers, as well as differentconcentrations of the nanofluid. The obtained results demonstrate that heat transferimproves with an increase in the volumetric fraction and Reynolds number.Dans ce travail, nous présentons une étude numérique de la convection mixte dans unecavité carrée remplis d?un nanofluide (Al2O3-eau) avec une marche (ascendante etdescendante). La paroi supérieure est maintenue à une température froide, la paroi latéraleest maintenue à une température chaude et le reste des parois sont supposéesadiabatiques .Les équations qui régissent ce phénomène ont été résolues par une approchenumérique, basée sur la méthode des volumes finis.L?étude a été réalisée pour différents nombres de Grashof, de Reynolds, différentesconcentrations du nanofluide . Les résultats obtenus montrent que le transfert de chaleur estmeilleur si la fraction volumique et le nombre de Reynolds sont augmentés.In this work, we present a numerical study of mixed convection in a square cavity filledwith a nanofluid (Al2O3-water) containing a step (upward and downward). The upper wallis maintained at a cold temperature, the side wall is maintained at a hot temperature, andthe remaining walls are assumed to be adiabatic. The governing equations for thisphenomenon have been solved using a numerical approach based on the finite volumemethod.The study was conducted for different Grashof and Reynolds numbers, as well as differentconcentrations of the nanofluid. The obtained results demonstrate that heat transferimproves with an increase in the volumetric fraction and Reynolds number.

Boudine Boubekeur, Rouabah Nouhad, Zaabat Mourad

كلية العلوم الدقيقة وعلوم الطبيعة والحياة-جامعة العربي بن مهيدي - أم البواقي · الجزائر

The interdisciplinary nature of polymer nanocomposite advanced in the materials, electronics, healthcare, manufacturing, and energy sectors. Polymers provide good environmental stability to the incorporated nanostructures and also they act as capping and reducing agents.CdS and Ag:MgO nanoparticles were synthesized by hydrothermal, sol-gel methods, respectively. CdS/PVC and Ag:MgO/PVC nanocomposites have been prepared by spin coating technique. The prepared samples are characterized by XRD, FTIR, Raman, SEM, AFM, PL, and UV analysis. The antibacterial and photocatalytic activities of the prepared samples are examined.The structural properties of the CdS/PVC nanocomposites have been studied using X-ray diffraction, FTIR and Raman methods. The CdS/PVC have been observed in hexagonal wurtzite structure nature.The structural studies of Ag:MgO/PVC nanocomposites are composed of metallic Ag and MgO phases and indicate that all the samples nanocomposites resemble the interaction between the polymer matrix and nanofiller particles.The surface morphology of the prepared nanocomposites has been observed by using SEM and AFM. The scanning electron microscope and atomic force microscopy images show that almost the particles are uniformly distributed in the polymer matrix with agglomeration of nanoparticles in the matrix after a certain concentration. .The optical properties have been examined using UV-Vis spectroscopy and Photoluminescence studies.The addition of CdS ,Ag:MgO nanoparticles in PVC polymer shifts the absorption edge wavelength towards the longer wavelength which reduces the band gap value lower than that of the pure PVC .The band gap values for the samples nanocomposites have been calculated to lie in the range of 4.1eV to 3.69eV.The antibacterial activity of Ag:MgO/PVC nanocomposites are tested against the bacterial strains Staphylococcus aureusand Escherichia coli. The Ag :MgO addition is enhanced the inhibition than pure PVC.The degradation of methylene blue dye by the pure PVC, CdS/PVC, and Ag:MgO/PVC nanocomposites are carried out by a specially designed photocatalytic reactor. The percentage of methylene blue dye degradation by the pure PVC, CdS/PVC and Ag:MgO nanocomposites 17%, 46%, and 52% respectively.The degradation efficiency of Ag:MgO/PVC is found better than the other samples

ضحي مازن لبابيدي, مني العسة

كلية الشريعة-جامعة دمشق · سوريا

فاطمة برماتي , ادريس بن خويا

كلية الآداب واللغات-جامعة أحمد دراية - أدرار · الجزائر

أحمد الماحي أبو بكر, أمير حسن محمد حماد

كلية الدراسات العليا والبحث العلمي-جامعة الرباط الوطني · السودان

تناول البحث موضوع كفاءة برنامج (ساهرون) في تعزيز الوعي الأمني للجمهور هدف البحث للإسهام العلمي، وذلك بالدراسة العملية العميقة لموضوع البحث لتوضيح أهمية كفاءة برنامج (ساهرون) التلفزيوني في تحقيق الوعي الأمني المنشود، ويتناول البحث المشكلات الأمنية في المجتمع بهدف رفع الوعي الأمني للجمهور وتحصينهم وتوعيتهم ضد المخاطر الأمنية حيث شملت الدراسة عدة تساؤلات: ما هي مجالات برامج التوعية التلفزيونية الأمنية ؟، ما مدى فاعلية البرامج التلفزيونية في تعزيز رسالة التوعية الأمنية ؟ ، ما مدى مساهمة برنامج ساهرون في تحقيق الوعي الأمني؟وقد تم في البحث استخدام منهج تحليل المضمون حيث وقع الاختيار على تحليل (68) حلقة تلفزيونية باستخدام أسلوب العينة العشوائية المنتظمة، للحلقات التي تم بثها في الفترة من 2010م حتى أكتوبر 2012م.وخلص البحث إلى عدة نتائج أهمها:1 – غياب التخطيط البرامجي في مجال التوعية الأمنية الذي يؤدي إلى عدم جذب أعداد كبيرة من المشاهدين وبالتالي عدم تحقيق الوعي الأمني المطلوب.2 – عدم إشراك الجمهور في كثير من الأحيان في بعض القضايا الأمنية مما يؤدي إلى إهمال دورهم في تحقيق شعار الأمن مسؤولية الجميع.3 – أحياناً لا يتم استخدام عنصري الجاذبية والتشويق عند تصميم بعض الرسائل التوعوية مما يؤدي إلى انصراف عدد كبير من المشاهدين لمتابعة البرنامج.4 – عدم إعطاء مساحة اكبر لمواضيع الشرطة الشعبية والمجتمعية وإشراك الجمهور في قضايا مجتمعهم لتحقيق الشراكة المجتمعية.

حليمة علام, سناء قويسم, فاروق جياب

معهد العلوم الإنسانية والاجتماعية-المركز الجامعي الشهيد سي الحواس - بريكة · الجزائر

فريدة موساوي, نصيرة بومناد

كلية الاداب واللغات-جامعة اكلى محند أولحاج - البويرة · الجزائر

Fatma Belarbi, Nawel Hamel

كلية الاداب واللغات-جامعة محمد خيضر - بسكرة · الجزائر

حامق محمد, شيماء ماحي

كلية العلوم الإنسانية والاجتماعية-جامعة ابن خلدون – تيارت · الجزائر

Ali Salih Gangi , Medani Ahmed Osman Abunearan, إبراهيم البشير محمد, الحسن صالح إبراهيم

كلية العلوم الزراعية-جامعة الجزيرة · السودان

Intercropping is gaining more attention in the developing world because it is a feasible, intensive and well planned way of raising agricultural production in the tropics. Hence, two experiments were conducted at the Gezira University Farm, Wad Medani, Sudan, during autumn and winter, 2005, and summer 2006. The experiments were arranged in a randomized complete block design with three replications. The first experiment was conducted to evaluate forage and grain yield of seven cowpea genotypes (Vigna unguiculata (L) Walp) as sole and intercropped with Sudan yellow pearl millet (Pennisetm americanum (L) Leeks) at five different arrangements (sole millet, paired rows of millet + single row of cowpea; alternate single row of each crop; paired rows of cowpea + single row of millet; sole seven cowpea genotypes). Many forage and grain yield components of each crop and their mixtures were measured. Relative yield (RY) and land equivalent ratio (LER) of both crops were assessed. Intercropping significantly increased the per plant growth parameters of both crops during the different growing seasons. Autumn forage and grain yield of the two crops was the highest followed by that of summer and then winter. Sole dry forage and grain yields of each crop component was lower than that of millet plus cowpea in intercropped treatments, however, it was higher than that of each crop separately. Across seasons, the highest dry forage yield of millet among the intercrop treatments was given by the intercrop combination of the landrace with paired rows of millet followed by genotypes IT95K-52-34 and IT97K-819-18 intercropped with millet at alternate single row. However, the highest dry forage yield of cowpea in the mixture was given by genotype IT95K-52-34 at paired rows of legume and alternate single row, followed by genotype IT98K-412-8 and IT98K-319-2 in alternate single row. Dry forage yields of both crops depends largely on leaf area and plant fresh weight plus days top 50% flowering (earliness or lateness) and growth habit(erect or spreading) for cowpea. The grain yield of the two crops (in sole or intercropped) followed the same trends of their dry forage yield. However, the highest grain yield of the intercropped millet across seasons, was given by the combination of millet and genotypes IT98K-412-8, IT97K-819-18 and the landrace, respectively, in paired rows of legume, but that of cowpea was furnished by genotypes IT98K-391-2 at all row combinations and IT99K-1122 in paired rows of legume too. The highest total dry forage yield of both millet and cowpea was reported for that of genotypes IT95K-52-34, landrace and IT98K-391-2 in alternate single rows and across seasons, but that of grain yield was given by the intercrop of genotype IT98K-412-8 during autumn and summer and genotype IT97K-461-4 during winter, both at paired rows combination. Among the measured parameters panicle yield greatly affected millet grain yield, while number of seeds per pod, 100-seed weight and days to 50% flowering were responsible for the large variation in cowpea grain yield. Most of the land equivalent ratio (LER) values for forage or grain yields exceeded 1.00 throughout the year indicating that intercropping gave yield advantage over sole or pure stands particularly at paired rows arrangements. In recommendation, it is suggested to grow millet-cowpea genotypes IT95K-52-34 or landrace or IT98K-391-2 in alternate rows for high forage yield throughout the year and genotype IT98K-412-8 during autumn and summer and genotype IT97K-461-4 during winter in paired rows. The second experiment was conducted to assess the potential of 18 exotic cowpea genotypes for high forage and grain yield. The traits measured were similar to those mentioned in the first experiment. In individual analysis of variance for seasons, significant differences were observed among genotypes for all characters studied except leaf area, weight of stem, number of pods/ plant, number of seeds / pod and grain yield during autumn season. The combined analysis showed that genotype x environment interaction was significant for dry forage and grain yield. This study identified IT95K-52-34 and IT89KD-288 as dual purpose (forage and grain) genotypes. The highest dry forage yielding genotypes were IT95K-52-34, IT89KD-288 and IT97K-1069-2 with range of 3.8 to 5.4t/ha. This could be attributed to their potential vegetative growth that intercepted more light energy (large leaf area), together with their late maturity periods. The highest grain yielding genotypes were IT98K-412-13 and IT98K-1399 with a range of 1.4 to 2.1 t/ha. This could be attributed to their genetic potential in yield, number of pods/plants and number of seeds/pod. The results of experiment two suggest that genotypes IT97K-1069-2, landrace and IT89K-288 for high forage yield during autumn, while the genotypes IT95K-52-34 and IT98K-412-13 during winter, and the genotypes IT89KD-288, IT95K-52-34 and IT96D-733 during summer seasons and throughout the year the highest dry forage yielders were genotypes IT89KD-288, IT95K-52-34 and IT97K-1096-2 the highest grain yielders were IT98K-412-13, IT99K-1060 and IT98K-131-2 during autumn. IT98K-428-3 and IT98K-412-8 during winter, and IT98K-1399 and IT98K-412-13 during summer, but throughout the year the genotypes IT98K-412-13 and IT98K-1399 were recommended. For dual purpose (grain and dry forage) it is suggested to grow the genotypes IT89KD-288, IT95K-52-34 and IT98K-412-13 throughout the year.