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.
The problem of internal sulfate attack in concrete is widespread in Iraq and neighboring countries.This is because of the high sulfate content usually present in sand and gravel used in it. In the present study the total effective sulfate in concrete was used to calculate the optimum SO3 content. Regression models were developed based on linear regression analysis to predict the optimum SO3 content usually referred as (O.G.C) in concrete. The data is separated to 155 for the development of the models and 37 for checking the models. Eight models were built for 28-days age. Then a late age (greater than 28-days) model was developed based on the predicted optimum SO3 content of 28-days and late age. Eight developed models were built for all
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في هذا البحث، تم تنفيذ الطريقة الحسابية الفعالة (ECM) المستندة إلى متعددة الحدود القياسية الأحادية لحل مشكلة تدفق جيفري-هامل غير الخطية. علاوة على ذلك، تم تطوير واقتراح الطرق الحسابية الفعالة الجديدة في هذه الدراسة من خلال وظائف أساسية مناسبة وهي متعددات الحدود تشيبشيف، بيرنشتاين، ليجندر، هيرمت. يؤدي استخدام الدوال الأساسية إلى تحويل المسألة غير الخطية إلى نظام جبري غير خطي من المعادلات، والذي يتم حله بع
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Study was done in the period between (2015–2017) in biology department in college of Education for pure science/Ibn Al-Haitham at Baghdad University and in Pathology department/college of medicine at Al-Nahrain University. The study was retrospectively designed. The clinicopathological parameters were obtained from patients’ admission case sheets and pathology reports (age, gender). The presents study included 120 patients having thyroid nodules, classified according to results of histopathology into 4 groups, 30 patients within each; the first group included patients with follicular adenoma, the second group included patients with follicular carcinoma, the third group included patients with follicular variant of papillary carcinoma (FV
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The study of the subject shows us the couflict between Somalian- Ethiopian. About Al-Oaghaden (1960-1978). This province is purely Somalian area in their language ،manners ،
traditions ،and their most population from Migrant bedouin.
In the last nineteenth century ،Ethiopia had entered to exit from plateau ،and become nearly from Red Sea and Indian Ocean.
The study shows us ،the conflict between colonization countries ،about African horn ،then fore Ethiopia entered as partner to divide the zone area ، and that division hadn’t Cares about the unity of people ،or the similar of language or religoun ،for this reason which had interference happened between broders and division about the same tribe from more Century ،
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The research's purpose is to highlight the role that the Approach of the strategic decision play in universities' governorships, assuming that the universities' governorship are definite result that can be reached by modern universities through their active strategic decisions that they take based on the correct way of thinking and the appropriate entrance that achieve the strategic goal of these decisions. The current research depended on two curriculums necessitated by the research requirement which are the analytical description curriculum and compare curriculum, the field research was done in the (Baghdad and Al-Mustansiriya) universities, the samples that were selected were the president, assistants and members of the board'
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The main problem of this research titled (the prevailing scientific values in children's programs provided by the channel (mbc3) is the disclosure of the scientific values that are included in the children's program in the mbc3 channel) which are directed to an important group of society, which is the category of children who spend long hours in front of TV screens to watch these programs, and therefore they acquire many values that can replace fixed values, such as social, moral, religious, etc., and the content analysis method has been used to analyze children's programs presented by mbc3 channel), and the research has reached a number of The results can be summarized b To come: |
Cuneiform texts are the most important sources for our knowledge of ancient history and in all political, economic, social and religious fields, as the ancients left us thousands of these texts, which were found through excavations, and hundreds of these texts were stolen and smuggled out of Iraq, and some of these texts were returned after the Jordanian government confiscated them and returned them to the Iraqi Museum. Most of these cuneiform texts were economic texts. In this research, a group of these confiscated cuneiform texts was studied (their number was six texts bearing the following museum numbers, respectively (160609 - 160103 - 160290 - 160102 - 206650 - 206637) dating back to the time of the king of the Larsa dynasty, Rim-Sin (
... Show Moreيكشف هذا المقال عن مشكلة الصفات ذات المكون الكمي والتي تعتبر واحدة من اقوى الموارد المكونة للكلمات التعبيرية والتقويمية و يتم تحليل التركيبات الدلالية ذات الاوجه المتعددة التي تنشا من عملية توظيف الصفات المشتقة بمساعدة اللواحق والتي تدل على الاتجاه العام للغات السلافية وذلك لتطوير الدلالات العاطفية والتقييمية في الكلمات ذات معنى الميزة او الخاصية يتم تقديم تعريف انماط تكوين المعاني الضمنية في دلالات
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