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 current research involves psychological pressure (educational,environment andemotionly) for secondary level to 2013-2014.This research includes comparison among students who are trained and not trained in physical education .The sample is(126) students from each gender from first education.Al-Karkh and the research found out that physical education has an effect in lessing emotional and educational in a big degree in student in secondary which affect them positively in their study. &n
... Show MoreThe research seeks to determine the nature of audit services, their characteristics and the basic concepts of services marketing audit and definition of the rules and basic dimensions of the marketing audit services through the knowledge of the elements of the marketing mix and test the preferences of customers and auditors of the factors affecting the marketing audit services by selecting a sample of the owners of some of the projects and companies and a sample of auditors has been use the resolution to achieve the objectives of the research where a good question to the owners about the most important factors in your choice of the Audit Office and asked the organization to answer according to the standard trio (very important, a few imp
... Show MoreThe calamities, calamities, problems and constant dilemmas that society is experiencing have made it the responsibility of professors and researchers to find appropriate and effective solutions to these issues, and among those calamities that our societies faced was the problem of the epidemic represented by (Corona-Covid-19)
The research is to use the specifications and detection of the main and secondary causes of the problems that lead to the weakness and low quality of local production in Iraqi companies and develop appropriate solutions to them, as Iraqi companies suffer from the low quality of production, And the adoption of the requirements of ISO 9001: 2008, which contributes to the development of production processes within the company, and through the field co-operation and survey conducted for public companies affiliated to the Ministry of Industry and Minerals, The importance of the research through the statement of the most important problems facing the General Company for vegetable oil industry in terms of low and weak in production qual
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The team of this investigation deals with phraseology and the importance of its organized use in the media of communication, especially in the daily newspaper which is used by different society classes.
So, the journalist
... Show Moreبلا شك ان عملية اختيار القرار الصائب للموظف من مجموعة التفضيلات المقدمة له، ستحقق بالتأكيد لديه الشعور بالرضا، وكما ستدفعه الى المزيد من اتخاذ القرارات نحو الخيارات من دون تردد او شك مما ستخلق في نفسه الثقة والرضا الذاتي والايجابية في التفكير . ونلاحظ بان اغلب موظفي الدولة يمارسون وظائف لا تبعث في نفوسهم الرضا سواء كانت تلك الوظائف تعود الى القطاعات الحكومية او القطاعات الخاصة، وذلك لأنهم قد اجبروا على ممارس
... Show Moreاللغة هبة من هبات الله عز وجل على عباده فهي أداة التواصل بل هي أداة الحياة ومن دونها لا تستقيم حياة ولا تتم. واللثغة هي نوع من الإبدال، وهي اضطراب صوتي قد يكون مرضا من أمراض الكلام.
There are words that are described in certain words that are not described in other words, so the relationship between two words that accompany a habit is strengthened, which leads to the emergence of a conjunction or an idiomatic expression. It did not exist before their association together,
أظهرت نتائج تقدير التركيب الكيميائي لمعزول بروتين بقول العدس المنبت التي تم الحصول عليها من الأسواق المحلية في محافظة بغداد وذلك باستخدام الاستخلاص القلوي عند الرقم الهيدروجيني 9.5 PH ثم الترسيب عند نقطة التعادل الكهربائي 4.5 PH،كانت نسبة البروتين، الرطوبة، الرماد، الألياف، الدهن والكربوهيدرات (71.58، 6.44، 2.58، 1.09، 0.25، 8.66) % على التوالي، وبينت نتائج تقدير المعادن في المعزول البروتيني لكل من الكالسيوم والفسفور والحد
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