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.
The current research involves psychological pressure (educational,environment andemotionly) for secondary level to 2013-2014.This research includes comparison among students who are trained and not trained in physical education .The sample is(126) students from each gender from first education.Al-Karkh and the research found out that physical education has an effect in lessing emotional and educational in a big degree in student in secondary which affect them positively in their study. &n
... Show MoreAndalucía, dentro del mapa lingüístico español, es una región con muchas variaciones dialécticas. En muchos casos contiene una gran variedad de términos propios de la zona, ya que en esta misma zona se pueden observar muchas subdivisiones dialectales.
En este trabajo, hemos seguido dos tipos de fuentes:
- Directa: Se trata de conseguir la información por medio de cuestionarios distribuidos a informantes de edades y localidades diferentes.
- Indirecta: Consultando libros para conseguir información y datos básicos del tema, e información sobre las voces y nombres dialectales en la geografía estudiada.
There are a lot of takes care of the legacy of the household (p) and from different Islamic sects, where draw works several dealt biography Zahra Virgin (p) was research deals with male workbooks that were classified for girlfriend (p) since the second century AH, which is my father Mkhnf, Lot bin Yahya bin Said Azdi (d. 157 AH / 773 AD) the first class
This search aimed to show a series of converses that our prophet [peace be upon him] call ,some of them , (Kufraa) , and explain the meaning of (AI-kufr) that called on some works , so does it mean the apparent part or the pronunciation of(Al-Kufr) has another meanings ?
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
Baalbek ( Heliopolis- the City of the Sun), one of the most important historical cities in Lebanon, has known as multiple civilizations in successive historical periods, which have left many archaeological evidences, the most important ones are the castle and the roman temples.
The Islamic architectural and artistic heritage in Baalbek was consisted from different types of buildings: religious, civil, military and social in addition to many archaeological arts that were mastered by the Muslims.
Background: Deep vein thrombosis is a multi causal disease and its one of most common venous disorder, but only one quarter of the patients who have signs and symptoms of a clot in the vein actually have thrombosis and need treatment .The disease can be difficult to diagnose. Venous ultrasound in combination with clinical finding is accurate for venous thromboembolism, its costly because a large number of patients with suspicious signs and symptoms. Venography still the gold standard for venous thromboembolism but it is invasive. The D-dimer increasingly is being seen as valuable tool rolling out venous thromboembolism and sparing low risk patients for further workup.Objectives: this study has designed the role of D-dimer to confirm diag
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