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).
Sloped solar chimney system is a solar chimney power plant with a sloped collector. Practically, the sloped collector can function as a chimney, then the chimney height can be reduced and the construction cost would be reduced.The continuity, Naver-stockes, energy and radiation transfer equations have been solved and carried out by Fluent software. The governing equations are solved for incompressible, 3-D, steady, turbulent standard model with Boussiuesq approximation to develop for the sloped solar chimney system in this study and evaluate the performance of solar chimney power plant in Baghdad city of Iraq numerically by Fluent (14) software with orking conditions such as solar radiation intensity (30
... Show MoreThe current work concerns preparing cobalt manganese ferrite (Co0.2Mn0.8Fe2O4) and decorating it with polyaniline (PAni) for supercapacitor applications. The X-ray diffraction findings (XRD) manifested a broad peak of PAni and a cubic structure of cobalt manganese ferrite with crystal sizes between 21 nm. The pictures were taken with a field emission scanning electron microscope (FE-SEM), which evidenced that the PAni has nanofibers (NFs) structures, grain size 33 – 55 nm, according to the method of preparation, where the hydrothermal method was used. The magnetic measurements (VSM) that were conducted at room temperature showed that the samples had definite magnetic properties. Additionally, it was noted that the saturation magnetizatio
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The non-linear components has been emphasized for its multiple applications in rewritable recording and data storage devices. Chalcogenide glasses materials are promising due to their high refractive index. In this paper, alloys for Ge30Te70-xSbxglasses semiconductor (where x =0.0, 5, 10, 15 and 20) will be fabricated by melt quenching method. The effect of partial substitution on DC electric power parameters, and its knowledge of electrical conduction mechanisms, were investigated to determine the effect of Antimony on the density of extended states, local states, and in Fermi energy states. The electrical measurements revealed the existence of three conduction mechanis
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يرمي هذا البحث الى تعرف اثر استراتيجية تعليم الاقران في تصحيح الفهم الخاطئ للمفاهيم الجغرافية لدى طالبات الصف الاول متوسط
التنمية المستدامة حق لكل البشرية وأنها مفهوم ٌ مركب من عنصرين هما التنمية واالستدامة مهمين متالصقين أي ال يوجد تنمية دون استدامة وال العكس يصح، وأنها تمتلك العديد دراسات سياسية وإستراتيجية من األهداف ويبرز هدف الـ)القضاء على الفقر، والقضاء على الجوع( ومن أهم أهدافها، هذه الظاهرة بارزة في المجتمع العراقي بسبب الحروب واالزمات المتكررة فيه وحاالت الحصار االقتصادي، وكذلك بسبب عدم توزيع موارده بشكل عادل من قبل
... Show MoreThe aim of this research is to know how business organizations achieve competitive advantage ,and make it sustainable through constructing a green strategy ( friend to environment) which is reflected on sustaining their competitive advantages .The problem of this study is presented through trying to answer many thoughtful questions, the most important of them are:
1-Can business organizations today make green strategies supporting their competitive advantage?
2-Is there a framework or mechanism could be depended on by business organizations to manage strategic risks of losing their competit
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the history of Damascus by Ibn ' asaakir d. 571 a.h. 1272 m from local histories books concerned with male citizen narrators, to distinguish between rate and Rob them, this book is more a history of Islamic heritage books on Islamic City, and if we know that Ibn ' asaakir translated it for personal
Abstract
The research aimed to prepare an audit program focusing on the activities of municipal institutions related to the environmental dimension as one of the dimensions of sustainable development, and applying the program for the purpose of preparing an oversight report related to assessing the impact of the activities of municipal institutions on the environmental reality as the main channel through which municipal institutions contribute to achieving the part related to it. Among the requirements of sustainable development, the proposed program was prepared and applied to the institutions affiliated to the Directorate of Mu
... Show Moreيهدف البحث إلى معرفة ما هيه اخلاقيات مهنة العاملين في المكتبات وتحديث متطلباتهم الضرورية من المهنة لكي يسمو بأخلاقياتها ، وهل هذه الاخلاقيات متوافرة في العاملين في مكتباتنا الجامعية ضمن حدود الدراسة ؟ ومن ادوات جمع البيانات : استمارة بالاخلاقيات وزعت على مجموعة من الاساتذة و استبانة وزعت على من المكتبات الجامعية . وكان مجتمع الدراسة العاملون في المكتبات المركزية الأولى والثانية لجامعة بغداد والمكتبة المرك
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