A numerical study of the two-dimensional steady free convection flow in an inclined annulus between two concentric square cavities filled with a porous medium is presented in this paper for the case when the side outer walls are kept with differentially heated temperature while the horizontal outer walls and the inner walls are insulated. The heated wall is assumed to have spatial sinusoidal temperature variation about a constant mean value. The Darcy model is used and the fluid is assumed to be a standard Boussinesq fluid. For the Cartesian coordinate system, the governing equations which were used in stream function form are discretized by using the finite difference method with successive under – relaxation method (SUR) and are solved by Gauss-Siedel iterative method. The upwind scheme was used for the transport terms in the energy conservation equation. The results are presented to demonstrate the streamlines, the isotherms, and the Nusselt number depending on the Rayleigh number ranging from (Ra =10 to 1000), dimension ratio from (Dr = 0.15 to 0.45), and the inclination angle from (= 0o to 45o). Also the effects of the amplitude (=0 to 1) and the wave number (f =0 to 5) of the heated side wall temperature variation on the free convection are investigated. The results show the effect of previous parameters (Ra, Dr,, , and f) on the flow fields and temperature profiles. It also show that the average Nusselt number is a strong function of the Rayleigh number, inclination angle, dimension ratio, and temperature variation. The peak value of the average Nusselt number based on the hot wall temperature is observed to occur at dimension ratio of (0.15), inclination angle of (40.1°), amplitude and wave number (1 & 0.75) for Rayleigh number of (1000).
This research examines the electrical, optical, and structural properties of zinc oxide (ZnO) and tin(IV) oxide (ZnO)1-x (SnO2)x composite thin films made by pulsed laser deposition, as well as the impact of composition concentration. The structural study of (ZnO)1-x (SnO2)x composites and thin films was conducted by X-ray analysis (XRD). Optical properties were investigated by UV–Vis infrared spectroscopy. The structural analysis revealed that all prepared thin-film composites were polycrystalline, exhibiting both hexagonal wurtzite and tetragonal phases for pure ZnO and SnO2, as well as a mixture of both phases for x=0.2 and 0.4. In contrast, the SnO2 phase was predominant for x=0.6 and 0.8. The increase in crystal size in the (
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This research aims to improve the process Tax accounting by using the scientific method to such as Six Sigma DMAIC steps called in General. Authority for Tax accounting . this approach has been described Tax accounting process Fully and identify problems experienced by the measurement and analysis and identify the critical success factors to satisfy customers and adoption process redesign Tax accounting process with the possibility of obtaining a high-quality revenue to be used by the body to improve its performance . Collected data and information from interviews with officials, staff and see the details & the conduct & operations in the body, and used well as a questionnair to measure the quality & services present action b
... Show Moreهدف هذا البحث الى استعمال الأسلوب الرياضي أسلوب التحليل الهرمي وتطبيقه وفق ابعاد بطاقة الاداء المتوازن في تقييم الأداء الاستراتيجي في الهيئة العامة للأثار والتراث، وتمثلت أدوات البحث باستعمال استمارات التحليل الهرمي وطبقت على معايير بطاقة الأداء المتوازن المتمثلة في (المالي، الزبائن، العمليات الداخلية، والتعلم والنمو)، وتم استهداف عينة قصدية متمثلة في رئيس الهيئة والمدراء العامون بعض من مدراء الأقسام ال
... Show Morehe is one of the most prominent Arab personalities who contributed in the Arab Muslim world, scholars and historians who appeared in the seventh century AH - the thirteenth century AD, contributed to enrich the Arab scientific heritage in his distinguished book “The Wonders of Creatures and the Strangeness of Existences” because it contained what God Almighty created and the oddities on dry land and water
The research deals with the Presidents of the Christians who called themselves (Ghaltka) in the book titled (orient chirsy patriarchs) that talked about their scientific practical biography adding to) that their completeness on the position of Ghaltka with its decrees and caliphs who were contemporaries to them ,as well as their places, deaths, cemeteries and their accomplishments In accordance with the powers granted to them and also it mentions the situation of The Abbasid caliphate with them and with the sons of their sect .
The current study aims at identifying of the differences of life quality level for the academic instructors at Omar Al-Mukhtar University / Libya according to the city variable that the instructor belong to ( Libya, Iraq, Egypt ), and also according to gender Variable (Male - Female),To achieve the aims of study ,the researcher chose a sample consists of (210) instructors ( 170 males and 40 females) from four colleges at Omar Al- Mukhtar University/ Darna . The researcher built the scale of life quality which consists of (42) items in last version . The researcher has conducted the validity and reliability of the scale. and by using Analysis of Variance via (SPSS program). The research reaches the following results : 1-The life quality o
... Show MoreThe Arabs muslim , throughout the historical ages, had many and varied contributions in various fields of science and knowledge, and in all scientific disciplines. They were preceded by scholars of other sects, so their books were translated into Arabic and they added to it many of their scientific research and writings that affected Arab and Islamic libraries, as these scientific research turned into basic references for the benefit of students of science in this field, and they did not stop at that, but built observatories, and invented They developed many astronomical devices in their time and observed the planets and stars, drew maps for them and determined their locations
هدف البحث إعداد تدريبات تزامن ما بين السايكو وتمرينات القوة الوظيفية للاعبي كرة القدم، والتعرف على تأثيرها في القدرة الانفجارية للرجلين، وفي مهارتي المناولة الطويلة والركلة الركنية للاعبي كرة القدم، ليفترض الباحث بإنه توجد فروق ذات دلالة إحصائية بين نتائج الاختبارات القبلية والبعدية لمجموعتي البحث التجريبية والضابطة في كل من القدرة الانفجارية للرجلين لمهارتي المناولة الطويلة والركلة الركنية في كرة القد
... Show Moreتلخصت مشکلة هذا البحث في التعرف على الدوافع التي تقف وراء تعرض الطلبة الدارسين في أقسام اللُّغة الإنکليزية للقنوات الفضائية الناطقة باللُّغة الإنکليزية والإشباعات المتحققة عن هذا التعرض في هذا المجتمع الخاص الذي يشکل بيئة اجتماعية علمية محددة، عن طريق تطبيق نظرية الإستخدامات والإشباعات في إطار المجتمعات الخاصة، وسعى هذا البحث إلى تحقيق ثلاثة أهداف هي، قياس استخدامات لطلبة الدارسين في أقسام اللُّغة الإنک
... Show Moreيهدف البحث الى تطبيق تزامن تصميم عملية انتاج معجون الاسنان في مصنع المامون التابع للشركة العامة للمنتوجات الغذائية مع نظام تكاليف الجودة المطبق في الشركة لتحقيق الميزة التنافسية. وتمثلت مشكلة البحث في أن الشركة عينة البحث لا تستخدم نظام تكاليف الجودة بالتزامن مع تصميم عملية إنتاج هذا المنتج لاغراض تحقيق الميزة التنافسية حيث تواجه منتجات الشركة منافسة عالية في الاسواق المحلية. إن الشركة تطبق نظام تكاليف الج
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