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.
Ibn Hajar is one of historian who had a role in historical writing represented by his writings in those active participation in the Arab-Islamic civilization, particularly his approach to intellectual, and pictures of us in his book that's part of the intellectual heritage, but a line that was a key part of the book, any manuscript
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 MoreThe conflicting duality of goodness and evil has a psychological effect on the life of humans, the nature of human beings is originally goodness whereas the tendency of evil flows from the society, therefore the first who found a meaning of evil on earth is kabeel when he quarreled fiercly with his brother who carried in himself all the meanings of goodness and toierance.
In this paper of mine we find that Robaayat Al khayam carries a poetic content of a special meaning in that every expression reflects semantic relationship (the good played a part in the formation lies with and the evil) of which its foundation lies with the human personality (soul), and he (the poet) a scribes it to matters of
... Show MoreThe curriculum balancer (comparative) (comparative linguistics), of great
importance in studies of language in general, and study any phenomenon of
acoustic phenomena, morphological, syntactic and semantic study of balance in the
Arabic language in the light of the dialects of the Arabian Peninsula, leading to
significant results in linguistic research, which could achieve Some issues that were
not up to where the old research conclusive results, and helps to explain things may
have created confusion if it did not mean the budget in the interpretation of the
study, as well as its importance in the origination of phenomena of language and
reasoning on the same phenomenon, followed by the Sisters Arab Veseltha.
H
Due to the importance of the word and because it is the basic building block from which speech is formed, it has become the subject of the attention of many scholars, ancient and modern, especially the Qur’anic vocabulary, which scholars dealt with in various branches of the Arabic language
التعددية الثقافية هي مفهوم يتعلق بالمجتمعات التي تضم ثقافات عده، أو العالم الذي يتضمن ثقافات متنوعة؛ فالتعددية هي التنوع الثقافي والفكري؛ وبالتالي هي عنصر إثراء للإنسانية وأساس لوجودها؛ فالتعددية الثقافية تتضمن القبول بالثقافات والافكار الانسانية كلها، وإفساح المجال أمامها للمشاركة في بنا ء الثقافة والفكر العالمي؛ وهكذا فإنها تتمثل في التسامح مع الثقافات والافكار المختلفة الاعتراف بالهويات والخصوصيات
... Show MoreThe present study deals with the social work and the social problems which
the Elderly who lives in the house of special needs suffer from . this study aims to
shed light to the most important social problems which they suffer from inside and
show their relationship and interaet with each ofher and what we can see about that
intereact either negative or positive relationship . Its scientific importance include
adding a new study in the field of take care of the Elderly . and that will enrich the
scientific field with agood knowledge . Becouse the studies in this part was little ,
but the scientific and practical importance of this study presents by the results and
specify of the important problems . In addition to
شغلت نظرية العدل الإلهي بال الأديب العراقي القديم، مما جعلته يثير عبر نصوصه الأدبية كثير من التساؤلات حول عدالة الإلهة، التي يعبدها ويقدم لها الهدايا وتساؤلاته هذه دفعت بالباحث إلى اختيارها عنوانا لموضوعه، إلا أن الدراسة ستختصر على نصوص معينة، والسبب في ذلك أنها كانت الرائدة في هذا الجانب، وفي اللحظة التي ينتقي فيها العدل الإلهي وتتحول الإلهة إلى كلاب تلهث وراء غرائزها، ذهبنا وراء الأسباب التي قادت إلى فقد
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