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.
العدد: دراسة مقارنة بين اللغة الاسبانية والعربية.
في العقود الملزمة للجانبين اذا لم ينفذ احد المتعاقدين التزامه تنفيذا كليا فانه يجوز للمتعاقد الاخر ان يطلب من المحكمة فسخ العقد فسخا كليا ، الا انه قد يقتصر عدم التنفيذ على جزء من التزامه فعندئذ يثار التساؤل الاتي: هل يمكن فسخ العقد فسخا جزئيا ؟ الملاحظ ان هنالك خلافا فقهيا وقضائيا كبيرا حول جواز الفسخ الجزئي ، فالبعض يجيز الحكم بالفسخ الجزئي ، والبعض الاخر لا يجيز الحكم بالفسخ الجزئي، وقد انتهينا الى القول بع
... Show MoreEtude de I' espace dans un extrait de Les sequestres d' Altona de Jean
Japans expansionist policy begins (Phase I) after the Chinese- Japanese
war in 1895 until end of the Washington conference in 1922 marine. Therefore
sought to implement the expansion program from the effect that get it after
Chinese- Japan war 1894-1895, and the Russo- Japanese conditions of the
first world war to complete its expansion program through the provision of
twenty- one demands and imposed on china.
In (1916-1917) it was signed a secret agreement with Allied power, that
including the German concessions in the far East to Japan legally has already
received official recognition from the international community.
In sum, the Japan during its period of expansion that has becom the first
Asian power tha
يناقش البحث الاسباب الحقيقية بتفشي الارهاب في العراق بعد العام 2003
This study aims to know how much and how long the Iraqi women's
watch space channels and expose to them and if these channels mee their
need to get knowledge information an entertainment . the role played by
these channels to provide Iraqi women with news about their community to
meet their needs and motives. this study also aims to know much the Iraqi
women expose to these channels and to know the favorable type of the
channels for them and the causes of that and know favorable programs and
why. also it aims to know the types of the if these channels deal with the Iraqi
women's problems and if the women get any advantage either behavior
knowledge for the watching these channels .
ابن حزم ، أبو محمد بن احمد بن سعيد بن حزم ، ولد في قرطبة (384هـ - 944م) وتوفي ودفن فيها عام (456هـ - 1016م) علم من أعلام الفكر الأندلسي ومن أجّل وأشهر مفكريه أصالة وعبقرية ، ويعد أفضل من مثل الثقافة الأندلسية في الحضارة العربية الإسلامية ، مفكر كبير ، وصاحب ثقافة واسعة غطت مجالات المعرفة كلها ، له اهتمامات متعددة يدل عليها كثرة تصانيفه والحقول التي كتب فيها ، حيث بلغ مجموع تأليفه نحو أربعة مائة مجلد (1) ، شملت فروع ا
... Show MoreThe Holy Qur’an is considered the miracle of God Almighty on earth, that will remain until the Hour of Resurrection, in which are evidences of His Power, Glory be to Him, and its verses are extremely perfect in miraculousness, including the shadow verses in the Holy Qur’an
ماهية الازمة الدولية : دراسة في الاطار النظري
المنظمات الدولية دراسة في منهجها وطبيعة فهمها