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.
Violence can be identified as an outreaching on others’ dignity,
freedom, properties, and life. Therefore, violent actions cannot be determined
only on materialistic attacks such as killing, beating, robbery, rape, and civil
wars, but it also includes the verbal attacks such as insult, threat, and cursing.
Violence against women can be identified as any bad actions that are
done against women, which lead to a physical or psychological harm, and
invade their safety and freedom whether these actions come from men or
women, against one woman or a group of women in special and general
places.
Before, the social, historical and lawful manners concentrated on
sexual distinction between the men and a woman, which
تم ت داول مصطلح الأزمة ا دلولية في السياسية ا دلولية خال القرن التاسع عش ر لتحدي دا ملدة الانتقالية بين السلم والحرب سواء أ دت الأزمة إلى نشوب صراع مسلح أم مت ت ت سويتها بالطرق السلمية، وتع دالأزمة ا دلولية مرحلة مت هيدية ل لحرب وهي ا رملحلة التي يسعى فيها أ طرا فالأزمة إلى إبعاد احتمالية نشوء أ و اندلاع الحرب، فالأزمة ه ي مدة حرجة ومرحلة خطيرة بين وقتي السلم والحرب، إن العلاقات ا دلولية تكاد ت عيشأ زمات متلاحقة ع
... Show Moreيرمي الكتاب الى التعرّف على خصائص البحوث المنشورة في مجلة الأستاذ وبيان السمات والمكونات الأساسية للمجلة واعداد كشافات تراكمية متنوعة لها . وجاء الكتاب في خمسة مباحث تناول المبحث الاول الاطار العام للبحث ،وضمَّ مشكلة البحث وأهميته وأهدافه واجراءاته والدراسات السابقة ،وتناول المبحث الثاني الدراسة النظرية وضم التعريف بـكشافات الدوريات ،وبيان أهميتها والتعريف بـ كلية التربية /ابن رشد وبيان أهدافها ،ومن ثم ا
... Show MoreThe legal text in the language of civil law, constitutional law, language of judges, and legal profession is concerned with a legal language and words that are coherently significant
اهتمام العلماء العرب بالحروف مبينين معانيه موضحين مقاصده
Addressed the problem of the research is marked (experimentation in caves fee) concept and its role in experimentation deviate Display Num formal charges caves. The search came in four sections: general framework for research and identified the research problem and the need for him. With an indication of the importance of his presence. Then specify the search for the goals of (revealed the nature and role of experimentation in determining the nature of Manifesting fee documented on the walls of caves), followed by the establishment of the three search limits (objectivity, the temporal and spatial) were then determine the terms related to the title. Then provide the theoretical framework and indicators that resulted from academic theorizi
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The Arab woman expressed the life of oppression that she suffers from in her masculine environment, as she expressed her linguistic abilities with eloquence and intelligence, as she did not neglect philosophy, wisdom, and exhortation
Abstract The Kenyan policy towards Somalia was influenced by a set of interrelated factors between the two countries and stemmed from the internal environment and most prominent: the geographical factor, ethnic, cultural, religious, political, economic and security, has been dominated by this policy since independence from the British colonial administration in the sixties of the last century and so far the nature of instability and tension, As the two countries are geographically contiguous and as security risks escalate, Kenya in 2011 rushed military action against Somalia, the first military action by Kenya outside its borders since independence.