Manal Awad Mohammed Ibrahim, Abdelbagi Osman Elsiddig Mustafa

كلية الهندسة والتكنولوجيا-جامعة الجزيرة · السودان

Energy conservation and its efficient usage in chemical process industries become the most debated issue considered worldwide due to the current energy crisis. This study is featuring energy optimization and retrofit for the Pre-heat Train heat exchanger network (HEN) of the crude distillation unit. The recent developed combinatorial approach of Paths Combination has been applied for such HEN to generate several energy retrofit options. Energy conservation was conducted by the means of utilizing heat shifting to reduce the energy consumption using each of the generated options. The heat shifting processwhich based on the (+/-) principle of pinch technology has been achieved using a simple developed Dev- C++computer programme. Heat shifting was conductedwhilekeeping a constant heat recovery approach temperature difference (HRAT) between hot and cold HEN streams. Shifting the heat from HEN utilities implies increasing the heat recovery between the processes’ streams. The penalty of increasing the heat recovery is to increase the heat transfer area for each of the affected exchanger in HEN without any topological modification. The obtained results had been analyzed economically to facilitate the decision of picking the most optimum retrofit solution. It was found that most of the generated options are located in the feasible zone of the HEN retrofit. Some of these options have showed a reduction in energy consumption in the range of 4964kW to save about 318K$/yr with 268K$ as penalty of capital investment to be returned within less than 1 year payback. The study recommended that the Dev-C++programming code which built for the heat shifting process in this study could be developed further to be adopted by ASPEN Plus Technology.

حمزة حمادة, حياة سباق محمد, حياة بلجاني

كلية الآداب واللغات-جامعة الشهيد حمة لخضر - الوادي · الجزائر

حفيظة درواش, احلام حرير, صورية بوكلخة

كلية اللغات والاداب-جامعة ابن خلدون – تيارت · الجزائر

نسعى من خلال هذا البحث إلى الوقوف على أبنية التعبير الكتابي الوظيفي لدى المتعلم، فالاتجاه الوظيفي يهدف إلى تعليم المتعلمين وكيفية توظيف المعارف والمكتسبات التي تلقوها في المدرسة وفي الحياة العملية وتوظيفها توظيفا صحيحا نطقا وكتابة، فاللغة وسيلة لإقامة الاتصال بين أفراد المجتمع، ويكون هذا الإتصال إما مشافهة أو كتابة، ويسعى هذا الاتجاه إلى جعل المتعلم قادرا على توظيف المعلومات المطلوبة منه عند الحاجة إلى استعمال التعبير الكتابي الوظيفي وفق القواعد التي يكتب بها، وعلى هذا الأساس فالهدف الذي يسعى الاتجاه الوظيفي الوصول إليه هو جعل المتعلم قادرا على توظيف قدراته اللغوية في الحياة العملية، وخاصة أثناء التعبير الكتابي الوظيفي بما يضمن له الحديث عن قدراته ومواهبه بشكل عملي وبراغماتي.

زهير نور الدايم محمود, هدى احمد حسن ابراهيم

كلية العلوم-جامعة الخرطوم · السودان

Abstract The study aimed to compare the taxonomy of the three species of the Nile Bulti from the Nile and its tributaries. Two hundreds and eight specimen were collected from the White Nile (Kosti), Blue Nile (Sinnar), Atbara River (Khashm El Girba) and main Nile (Al Sabloga). From each specimen 21 morphometric measurements, 12 meristic counts were recorded. For molecular genetics tissue samples from gills, fins, scales, liver and muscles were from each specimens and preserved in absolute alcohol for molecular studies. The ratio indices, morphometric, meristic and RAPD PCR were used to study and compare similarities and differences between the Nile Bulti from the four study sites. When two species are present in an area t-test was used for comparing morphometric measurements and the two independent tests for comparing meristic counts. When three species are present in an area one way ANOVA test was used for morphometric measurements and K independent sample test was used for meristic counts. The differences between species in both characters were statistically significant (pX04; 0.003-0.0000). The results of Discriminant analysis clearly separated between the different species within an area and between species at the different areas and Wilks Lambda values were extremely highly significant (0.004-0.0000). The result of RAPD PCR indicated hybridization between the species as the similarity coefficient ranged from 0.46 to 0.53. The derived dendrograms based on meristic counts was closer to that derived from the RAPD PCR than that obtained from morphometric measurements. The findings indicated that the ratio indices is tedious and not in conformity within the recent advances in numerical taxonomy. Subjection of the data to discriminate analysis reduced with 50-100% confidence, the characters to be measured from 21 to 3 in this study. The study showed co-existence of O. niloticus, S. galilaeus and T. zilli in the White Nile, O. niloticus and S. galilaeus in Blue Nile, O. niloticus and T. zilli in Atbara River and O. niloticus, and S. galilaeus in Nile. The RAPD PCR suggested interbreeding between O. niloticus, S. galilaeus and T. zilli.

جهاد حسن محمود سلامة, عصام حسن اللوح, فايز علي الأسود

كلية التربية -جامعة الازهر - غزة-جامعة الازهر - غزة · فلسطين

Ali Chachoua, Mohamed Zitouni

كلية الرياضيات-جامعة العلوم والتكنولوجيا هواري بومدين - الجزائر · الجزائر

Il s'agit de quelques propriétés des Courbes Elliptiques à invariant modulaire nul. J'ai commencé par l'étude des Variétés Algébriques : affines, projectives, abéliennes .Ensuite j'ai traité les Courbes Algébriques planes et leur genre, les Cubiques de Weierstrass : équations, invariants, classifications et les Courbes Elliptiques. Par la suite j'ai décrit le groupe additif abélien de Mordell-Weil E(K) d'une Courbe Elliptique E, son groupe de torsion T(E(K)),en particulier quand K= Q , les isomorphismes de Courbes Elliptiques .J'ai déterminé 5 familles de Courbes Elliptiques à invariant modulaire nul .J'ai par la suite présenté la courbe de Fermat x 3 + y 3 = z 3 qui est aussi une Courbe Elliptique à invariant modulaire nul.

سامر أحمد قاسم, نور حسن وحود

كلية الاقتصاد-جامعة تشرين · سوريا

حسن تيسير شموط, يونس أحمد عبدالرحمن عنانزة

كلية الشريعة-جامعة جرش · الاردن

Hamlaoui Katib, Lemmoui Abdennacer

كلية علوم المهندس-جامعة باجي مختار - عنابة · الجزائر

سهام خروبي, وسيلة مهنى

كلية اللغات والاداب-جامعة ابن خلدون – تيارت · الجزائر

La présente étude traite la question de l’influence du recours à la langue maternelle sur les pratiques langagières des apprenants de la première année moyenne en classe de fle. Les résultats obtenus confirment nos hypothèses de départ qu’estiment que le recours à la langue maternelle influerait négativement les échanges langagiers des apprenants et que ces derniers pourrait être garanties sans pour autant avoir recours à la langue mère. Cela veut dire que les apprenants peuvent établir une véritable communication en classe de fle et ce, sans utiliser la langue maternelle. () The present study treats the question of the influence of having recourse to the mother tongue on the first School student’s practices language. The results obtained confirm our initial hypothesis which estimates that the recourse to the mother tongue would negatively influence their language practices and that these latter could be guaranteed without having recourse to the mother tongue