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.
המחקר מתייחס לתופעת ההקטנה משני ענפים את הסימנטיקה והמורפופונולוגיה בשפה העברית, ומנסה ליגלוי את המשמעות בתוך ההקשר של צורות ההקטנה לדוגמאות מן התורה טקסטים מחדשות, שירה וסיפורים, הרי שחלק מהמשמעויות של מבנה הפלט עומדות בניגוד למשמעויות הבסיס או הדרגה במשמעות, כך מביעות על (הקטנה, חיבה, או זלזול) שרובן לא התקיימו בעברית הקלאסית, מצד אחר המחקר בדק במבנים המורפולוגיים במייוחד (המשקלים של צורת ההקטנה) ומבחין את
... Show MoreThe importance the youth because they are the fundamental basis of the development process so to be an emphasis on their active participation in community building . When there is community participation the democratization . Will tazzfa community because the process of community participation and develop the capacity to carry on almsoulin among young people and will lead to culture of self confidence and alhawwar walaklauah . Beactivted and community participation for young people through several channels . Family , school , media and civil society organization as we discussed in the research factrstnat hinder community participation of youth in development . The most important factors that hinder participating based on patriarc
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This paper shed light on castles in Iraq through Othman reign to know their sorts , and studying planning concentrating on the nature of architecture , this is a serious trying to study and important side of military architecture in Iraq with its reasons of building them which had related with political, military , social ,and economical circumstances of country .
Each of the languages possesses a set of phenomena that researchers in its sciences should stop at to explain the secrets of this language, including the phenomenon of idiomatic expression. Perhaps this phenomenon may constitute an obstacle to non-native speakers of the language or even the native speakers themselves. The Arabic language is full of these expressions, Which needs us to dedicate its own studies to it so that we can collect it in a dictionary that includes and collects it with explanation and interpretation of its semantics
يسلط هذا البحث الضوء على ظاهرة لغوية، والتي يطلق عليها تسمية "التضاد". يبين هذا البحث مفهوم هذه الظاهرة، خصائصها، أنواعها، وأسبابها، في اللغتين الساميتين: السريانية والعبرية. حيث تم اعتماد المنهج المقارن في دراسة هذه الظاهرة اللغوية وتبيان وجوه التشابه واالختالف في ماهية هذا النوع من المفردات، أي األضداد، في اللغتين: السريانية والعبرية. ويشير البحث إلى نوعين من التضاد وهما: التضاد الذي يكون بين مفردتين مستقل
... Show MoreThe essential objective of this study presents a analyzes of the combination of reality and fantasy in three dramas of Spanish author Alejandro Casona. "Trees die standing" (premiered in Buenos Aires in 1949), “Prohibited suicide in spring” (premiered in Mexico in 1937) and "The boat without fisherman" (premiered in Buenos Aires in 1945).
The first part is an introduction about the biography of Spanish author Alejandro Casona that will allow us to understand some peculiarities of his work in relation to the social historical context of his time.
In the second part of this study we have analyzed elements of reality and fantasy in the th
... Show MoreThe argumentation find its origins in some conceptions laid by Aristote. A speaker always intends to influence his hearers to change their beliefs. Therefore, this study deals with texts of the political speech of the French presidents Nicolas Sarkozy and François Hollande in the treatment of argumentative strategies.
