The design, construction and investigation of experimental study of two compound parabolic concentrators (CPCs) with tubular absorber have been presented. The performance of CPCs have been evaluated by using outdoor experimental measurements including the instantaneous thermal efficiency. The two CPCs are tested instantly by holding them on a common structure. Many tests are conducted in the present work by truncating one of them in three different levels. For each truncation the acceptance half angle (θc) was changed. Geometrically, the acceptance half angle for standard CPC is (26o). For the truncation levels for the other CPC 1, 2 and 3 the acceptance half angle were 20o, 26o and 59o, consequently. A significant difference between the instantaneous thermal efficiency of 3.86× CPC (θc=20o) and 2.32× CPC (θc=26o), and between that for 3.61× CPC (θc=26o) and 2.32× CPC (θc=26o). It's noticed that the difference between the instantaneous thermal efficiency of 2.32× CPC (θc=59o) and 2.32× CPC (θc=26o) is small compared with the difference of the first and second cases, the instantaneous thermal efficiency of 2.32× CPC (26o) was higher than those for other three CPCs. The experimental results show that the maximum thermal efficiency of the full 2.32×CPC (26o) is 0.708, the maximum thermal efficiency of the 3.93×CPC (15o), when it's truncated to 3.84× CPC (20o), 3.61× CPC (26o) and 2.32× CPC (59o) are 0.51, 0.52 and 0.66, respectively. As the concentration ratio decreases from (3.93× to 1×), the thermal efficiency, energy losses and optical efficiency increase from (0.47 to 63), (1.58 to 7.2 K.m2/W) and (0.494 to 0.797), respectively.
ان المشكلة البحثية تتحدد في ان المهام والادوات التي تملكها السلطة التنفيذية، من الصعوبة تركها من دون رقابة، والرقابة والتقييد ياتي من اطراف عدة، واهمها: السلطة التشريعية، فالبرلمان في العراق منح اختصاصات للنظر في اعمال واداء السلطة التنفيذية بما يضمن تقيدها بالدستور الاتحادي. والهدف من هذا البحث هو الاشارة الى اهمية الاختصاصات الممنوحة للبرلمان العراقي، بما يضمن التاسيس لدولة القانون، اي وجود مرجعية قانو
... Show MoreThe aim of the present research is to know the following :
What are the Science and technology, society and environment issues (S.T.S.E) which included in the content of the chemistry Book third grade intermediate ?
And to achieve the objective of search The two researchers has prepares a list of science and technology, society and environment issues (STSE) consisted of (9) key issues namely ( Air quality and the atmosphere, sustainable development, water security, health and preventive security, mineral resources investment, pollution of various kinds, energy, food industry, production of weapons technology ) and from which (70) sub-issues emerge, Arbitrators competent agreement has been received . Then, the two re
... Show MoreThis paper deals with constructing a model of fuzzy linear programming with application on fuels product of Dura- refinery , which consist of seven products that have direct effect ondaily consumption . After Building the model which consist of objective function represents the selling prices ofthe products and fuzzy productions constraints and fuzzy demand constraints addition to production requirements constraints , we used program of ( WIN QSB ) to find the optimal solution
Özet
Sözlü Türk halk edebiyatı ürünleri içinde önemli yere sahip olan türlerden biri de atasözleridir. Atasözleri, nesilden nesile halk ağzında dolaĢan, kimin söylediği bilinmeyen, birtakım gerçekleri kısa ve öz bir Ģekilde ifade eden sözlerdir. Türk atasözleri Orhun Abideleri‟nde ilk kez karĢımıza çıkmakla birlikte, Uygur dönemi yazıtlarında ve özellikle Dîvânü Lûgati‟t Türk‟te geniĢ yer bulmuĢtur. Dilin anlatım ve kullanım imkânlarını geliĢtiren atasözlerine, dünyanın bütün dillerinde rastlanabilir. Bunun için, söyleyiĢte güzel, anlatımda güçlü, kavramda önemli unsurlar içeren kalıplaĢmıĢ sözler halinde bulunurlar. Bu çalıĢmada, Türk halk edebiyatında atas
Support vector machines (SVMs) are supervised learning models that analyze data for classification or regression. For classification, SVM is widely used by selecting an optimal hyperplane that separates two classes. SVM has very good accuracy and extremally robust comparing with some other classification methods such as logistics linear regression, random forest, k-nearest neighbor and naïve model. However, working with large datasets can cause many problems such as time-consuming and inefficient results. In this paper, the SVM has been modified by using a stochastic Gradient descent process. The modified method, stochastic gradient descent SVM (SGD-SVM), checked by using two simulation datasets. Since the classification of different ca
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(6)
Levels of the Factors structure of the scale Costa and McCrae applied to the Iraqi environment
A previously_prepared Iraqi version of Costa & McCrae the big five factor has been adminstered to (200) students at University of Baghdad in order to investigate the hypothesized differences in factor structures between the original version of Costa & McCrae test and the Iraqi version.
To verify the hypothesized differences , the minieigen value. Factors , maximum likelihood criteria of determining the number of factors , and varimax and promax as methods of rotation have been used.
The
... Show MoreOperated Alandziahih "drift theory" as a science talk in most of the cash and technical studies in the early twentieth century, making him and the sciences, arts and culture both fields of experiences, in an attempt to explore the institutions that theory, a number of laws which took control in the internal structures of those acts, resulting in for those institutions to be actively contribute their ideas to guide the pace on the right track. And thus lay the foundations of this theory, which was a big affair in the early twentieth century and still vigorous pace to this day, particularly their applications in various fields of the arts.Although each type of Arts, both in the composition or the theater or means of communication, took joi
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The undimensionality hypothesis which is item response theory depend it is unable in some of measurement situations because there are many dimensions which are affect of the response, so as the researches reached to expand this hypothesis to construct a new one which is multidimensional, and many of theories are pointed to the concept of meaning of life is multidimensionality, so this research aimed to construct the scale of meaning of life as the student's perception according with Multidimensional Item Response Model and this research adopt Wong's theory 1998 which point to the meaning of life consist of (7) dimensions. The research tool contains (49) items distributed at dimensions of meaning of life. Sample of statistical ana
... Show MoreThe importance of the topic lies in explaining the extent of Sheikh Abdul Qadir Al-Kilani’s interest in social and scientific life in Baghdad
ان الحرب الاوكرانية والتصعيد الروسي ضد اوكرانيا يرتبط بصراع جيوسياسي واسع على مناطق القوة والنفوذ والمجالات الحيوية، وتنافس تجاري دولي محتدم على النفط والغاز ومسارات خطوط التجارة الدولية بين اقطاب استراتيجية دولية تتجاوز اوكرانيا، إذ يأتي الصراع ضمن اطار التحولات الدولية الراهنة والصراعات على مناطق القوة والنفوذ الجيوستراتيجي والمكانة الدولية بين القوى الدولية المؤثرة في القضايا والشؤون الدولية، ويبق
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