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.
منذ بداية نشوء المستشفيات كمنظمات تعنى بصحة الناس، عُرف الصراع (Conflict) بين جماعتي الإدارة والأطباء. وقد تركز محوره في معظم الأحيان حول سلطة أي منهما هي الأقوى في اتخاذ قرارات المستشفى.. هذا إذا ما علمنا أن كل من الطرفين المتعارضين يستمد قوته ويعزز مكانته من خلال سلطته في اتخاذ القرارات. إن جهود كلا الجماعتين الطبية والإدارية تصب في منهل واحد ألا وهو خدمة المريض والارتقاء بالمستوى الصحي ل
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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,
Karbala is one of the oldest cities in Iraq. It was named after the name of the child. This is the saga that Imam Hussein was martyred in
ان ترجمة الافعال التي تصف احداث جارية وقت لحظة التكلم او في حالة استمرارية تفصح عن اختلافًا جذريا بين الإسبانية والعربية بسبب طبيعة الأفعال التي تصف هذه الأحداث، منها تعقيد بعض الصيغ، خاصة باللغة العربية، وعدم التكافؤ النحوي بين اللغتين في الكثير من البنى اللغوية. بهذا المعنى ، نجد أنه في اللغة العربية ، تتم صياغة هذه الظواهر اللغوية عن طريق أفعال تسمى الأفعال الناقصة التي تختلف طبيعتها ووظيفتها داخل الجملة
... Show Moreعرف العرب ، منذ القدم ، الأحجار الكريمة وعنوا بإقتناء أنواعا عديدة منها ، حيث كانت من أهم واردات سكان بلاد وادي الرافدين من السومريين والبابليين ثم الآشوريين ، كما عرفها المصريون القدماء وغيرهم من الشعوب القديمة ، فوجدت في قبورهم ومدافنهم وخزائن كنوزهم، مثل الياقوت الأحمر واللازورد واللؤلؤ . بالإضافة إلى ذلك فقد كان معدني الذهب والفضة من المعادن الوفيرة في هذه البلاد ، ولها الأولوية في صناعة الحلي.
Individual cannot live alone due to to his need for others to facilitate His supplies for living, thus social affiliation is considered one of the most important psychological, social needs in individuals life through his willing to affiliate to others whether they were friends ,family, colleague , or even home to reach some degree of psychological stability.
Affiliation is a tool to search for Satiate through living with group from the same type or comply for group or to be compatible with them or even to be adherent and accept what the group agreed about of criterion.
 
... Show MoreThe collapse of Al-Khwarizmi state is due to special factors relating to Al-Khwarizmi state, and general factors submit to the standards of fighting, and of the Islamic countries and the inability of the Islamic world to confront all the challenges it faced, especially the Mongols and frequent glamour and and conflict on the governance: (who receive the leadership, and who kills of, and who fights of) all these conditions led
Praise be to God, Lord of the worlds, and may blessings and peace be upon the most honorable of all creation, Abi Al-Qasim Muhammad, and the God of the good and pure
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