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.
Every era characterizes with its thought and life philosophy , where Muslims left behind them educational and intellectual heritage we should proud of it because it reflects the image of past and lights the way of present and future path where we should make use of it to fit with our statuesque and contemporary issues because we don’t know about it but little as result of ignorance or imitation of the western culture.
It’s wrong to regard heritage from the past but aphasia of Islamic and Arab genies that its roots tracing back to past and extending to future .
Islamic Arab educational thought regards one of the ric
... Show Moreيعد التأمين أحد المؤسسات المالية ذات التأثير على برامج التنمية ، وما زال قطاع التأمين يعاني من العديد من المشاكل منها الوعي أو التشريع أو كيفية توظيفه كمورد اقتصادي واجتماعي خدمة للمجتمع والمؤسسات والافراد. وحيث أن التأمين يقدم خدمة تستوجب التزامها بمواصفات محددة ، لذا أصبح من الضروري دراسة آليات تحسين جودة الخدمة التأمينية وكذلك دراسة واقع العملية التسويقية للخدمة التأمينية وما ينالها من تحديات داخلية أ
... Show MoreConsiders births illegal for children (illegitimate) phenomenon of negative social phenomena in our society where it's dangerous and the superiority of gravity on other social phenomena Calanhrav, homelessness and other due to poor drainage energies and sexual dysfunction in the value system among its actors and is characterized by the absence of social conscience and a lack of morality and the weakness of the system human-reliance among others.
The morality is the obvious difference between humans and animals. Wade this to say social scientists, while human social animal they said no that he has morals and values do not exist in other organisms so well that births
... Show Morethe boot of honesty in the dictionary the term linguistic and religious
heritage, literary and Islamic Sufi thought, and concept in the literature of Imam
Ali, peace is upon him. And studied the summary first concerns its presence in the
literature and implications and directions, either the second part, has cared for the
analytical study has found research that safe weight was the counterpart of the
personality of the Imam accompanied the character most prominent in his
character, namely, (courage), it has struggled to deliver a impact of humanity in his
time and after the word and deed, It was based on the imagination in the formation
of images sensual and intellectual, to his persuasion of the evidence and argu
Quran orders and commandments and principles, has avenged children, their status and dearest, and saved their lives, which reached ill before Islam, and filled the hearts of the fathers and mothers for their love, but to make them embellish life.
It is summarized that Abu-Baker Al-Soly is one of Arabic Muslim scientists who had special style in literary writing specifically in sciences and knowledge that had depended on the encyclopedia culture gained from various fields of science , this means that he was an individual who had participated to characterize features of Islamic –Arabic history enhanced the rules of it , this matter would encourage us to know the method and style of writing in the field of intellectual life in which the writer depended on the procedures direction of scientists that he lived in the Abbasid era .