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.
Day after day, Morsek literature 879-1018/1492-1609proves the completion of all literary branches starting from poetry with its different purposes to include prose with its various subjects. In 2016, a complete text of ‘the literature of Morsek journey
Day after day, Morsek literature 879-1018/1492-1609proves the completion of all literary branches starting from poetry with its different purposes to include prose with its various subjects. In 2016, a complete text of ‘the literature of Morsek journeys
Forward-swept wings were researched and introduced to improve maneuverability, control, and fuel efficiency while reducing drag and they are often used alongside canards, to further enhance their characteristics. In this research, the effects of canard dihedral angles on the wing loading of a forward-swept wing in transonic flow conditions were studied, as the wing loading provides a measure of wing’s efficiency (lift/drag). A generic aircraft model from literatures was selected, simulated, and compared to, using CFD software ANSYS/Fluent where the flow equations were solved to calculate the aerodynamic characteristics. The research was carried at two different Mach numbers, 0.6 and 0.9, for five different canard dihedral angles which tra
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المستخلص: يهدف البحث الى التعرف على بقاء اثر المعلومة عن طريق الاجابة عن السؤال: ما مدى بقاء اثر التعلم بين التعليم الالكتروني والتعليم االحضوري ؟ تم تطبيق البحث في العام الدراسي( 2020-2021 م) في العراق. تم استخدام المنهج الوصفي بالاسلوب المقارن في عقد مقارنة بين التعليم الالكتروني والتعليم الحضوري. وكان مجتمع البحث من طلبة المرحلة الرابعة كلية التربية للعلوم الصرفة – ابن الهيثم ,و العيتة من قسم الرياضيات الم
... Show Moreتمثل هذه النقوش طبيعة العصر فيه ؛ لذلك نجد الباحثين المهتمين بعلم اآلثار ، والتاريخ القديم هم أكثر من بحث عنها ، ثم حاولوا فك رموزها ، وما زال بعضها قيد الدراسة .
Prince Kikaus explained to us Conditions of writing and establishing .Then he touched upon the Conditions of the ministry and qualities that must be characterized Author and minister both need machines must be availabla in person if given these positions .he was creative in presenting his ideas which is not without judgment an knowledge.He had a distinct style in mentioned professions and administrative hierarchy As explained in his speech About the writer and his Correspondence and construction and writer position who has developed into a minister then he touched it to the cabinet system and what the minister should do.of qualities .and the importance of the post of minister who mentioned several points to him ou
... Show Moreيستهدف البحث الحالي التعرف إلى 1 .بناء مقياس سمات الشخصية المفضلة لدى معلمي ومعلمات التربية الخاصة في العراق من وجهة نظر ذوي اإلختصاص والعاملين في هذا المجال. 2 .مستوى توافر سمات الشخصية المفضلة لدى معلمي ومعلمات التربية الخاصة في العراق من وجهة نظر ذوي اإلختصاص والعاملين في هذا المجال. 3 .داللة الفروق اإلحصائية في سمات الشخصية المفضلة لدى معلمي ومعلمات التربية الخاصة ً في الع ارق من وجهة نظر ذوي اإلختصاص والعا
... Show MorePrograms directed to children through the media in general and in television in particular are among the main factors that help in forming the cultural and educational values of this important segment of society, and in light of this the study problem was identified in answering a major question: What are the cultural and educational values that Ajyal channel seeks Space planted in children through my program, Iftah Ya Simsim (in its new season) and Friends of Ajyal? , While the objectives of the study were evident in identifying the most prominent cultural and educational values that the Ajyal satellite channel worked to instill in children, and identifying the nature of the techniques used by Ajyal channel in providing the value conten
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The researcher aims at focusing on the participations of children journalism in supplying the educational values for them. The researcher uses the survey method in addition to the method of content analysis through analyzing the content of two journals (Majalati and The Mezmar). Both of them deal with children issues.
The researcher concludes that the two journals focus on literary arts in a way which surpasses the journalistic arts. Furthermore, the two journals have concerned with showing the positive values as well as insuring the necessity of rectifying the wrong behaviors. Finally, the researcher recommends that it is necessary to improve the employees who work with children j
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The definition of the role of any institution in society is achieved through its objectives, The same is true for the military and how to deal with security threats in the humanitarian field ,Terrorism, which has almost replaced the traditional pattern of war, has waged a street war and intimidated individuals, families and society ,On the other hand, he found someone to meet him from a popular crowd of volunteers to defend their homeland from different sects, sects and religions, Thus, our study will be exposed to the role of popular mobilization in human security from a sociological point of view in Samarra, a field study of 100 male and female respondents.