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).
أهمية البحث والحاجة إليه:
من مظاهر التواصل الحضاري في جانبه العلمي والتكنولوجي هو متابعة أبناء مجتمعنا ولاسيما الشباب لكل منجز حديث واتخاذه وسيلة للحصول على المعلومات والمعرفة والتسلية، بحيث أصبح هذا التعامل ممارسة يومية حياتية، وهذا دليل على مدى تفتح ذهنية وعقلية ورغبات أبنائنا ومواكبتهم لروح العصر ومتطلباته وتعبيراً صادقاً عنه فضلاً عن إشغال أوقات ف
... Show MoreThe cuneiform texts considered one of the most important resources which play an important role help us to know how was the economic , politic and religious manner and every thing have relation of the history of Mesopotamia which contain many of information that enrich our knowldgement every side of Mesopotamia civilization since using writing as away to register the science and human knowldgement . The city of Sippar (Abu –Habba ) was one of most important city of ancient Mesopotamia which mentioned as one of first five Mesopotamian cities found before floating and it exposed through excavating rich one of them tablet which some of it dated to old Babylon period . The king Ammi-Saduqa has a big share of tablet we study number of thi
... Show Moreتناول البحث دراسة خمسة نصوص مسمارية لقروض غير منشورة من سلالة أور الثالثة وتحليلها وترجمتها وهي من مجموعة المتحف العراقي, يعود تاريخها الى زمن سلالة أور الثالثة (2012-2004ق.م) تحديدا الى زمن الملكين شوسين (2037- 2029ق.م) وابي سين (2028-2004 ق.م), اما مضامينها فهي قروض بمادتي الشعير(ثلاثة نصوص) الفضة (نصان), والقروض على نوعين قروض بفائدة (ur5 - ra), وقروض بدون فائدة (maš2 - nu - tuk), وقد حددت نسبة الفائدة في القروض 1/3 33% لمادة الشعير و20% لما
... Show Moreشهدت معظم المدن السومرية أزدهاراً أقتصادياً خلال عصر أور الثالثة ،أنعكس ذلك من خلال النصوص المسمارية المكتشفة ذات المضامين الاقتصادية المتنوعة ومنها (وصولات تسلم Bullae) التي تميزت بعصر أور الثالثة بأشكالها المتعددة ومنها: الكروية والمربعة والمستطيلة والمثلثة والمضلعة ومعظمها يحتوي على طبعات أختام فضلاً عن أنها تكون مثقوبة طولياً لغرض التعليق.
This study is about finding the estimation of tow equations, the comparative has been done between the estimations by using seemingly unrelated regression equations for the variable and random error has been distribution with poisson and the variable and random error has been distribution with normal and the method by using oldenary lest square.
While in the application side, we have estimated the parameter of investment specification function for the sector of agriculture with the industry sector is enabled us to obtain an estimation efficiency for the model of seemingly unrelated Poisson regression equation.
المستخلص
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Recurrent strokes can be devastating, often resulting in severe disability or death. However, nearly 90% of the causes of recurrent stroke are modifiable, which means recurrent strokes can be averted by controlling risk factors, which are mainly behavioral and metabolic in nature. Thus, it shows that from the previous works that recurrent stroke prediction model could help in minimizing the possibility of getting recurrent stroke. Previous works have shown promising results in predicting first-time stroke cases with machine learning approaches. However, there are limited works on recurrent stroke prediction using machine learning methods. Hence, this work is proposed to perform an empirical analysis and to investigate machine learning al
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This paper provides an attempt for modeling rate of penetration (ROP) for an Iraqi oil field with aid of mud logging data. Data of Umm Radhuma formation was selected for this modeling. These data include weight on bit, rotary speed, flow rate and mud density. A statistical approach was applied on these data for improving rate of penetration modeling. As result, an empirical linear ROP model has been developed with good fitness when compared with actual data. Also, a nonlinear regression analysis of different forms was attempted, and the results showed that the power model has good predicting capability with respect to other forms.