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.
Prophecy, the Jews had another concept, does not limit to choosen from God, but expands to include all of the claims to prophethood of priests and magicians and liars, The word prophet in the eyes of the Jews view has abroad meaning, That included the prophets who were chosen by God to his message, in order to repair case Also those, who were of magicians, astrologer & hypocrites
The historical documentation of the architectural archeology has a fundamental and great importance in evaluating the architectural product that has suffered from neglect
Markets had organized in Islamic cities since the time of the Prophet Muhammad(pbuh),
The 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
Labor movement is considered important in Britain because it is an international phenomenon of the feudal system and one of the flowerings of the era of the capitalist machine. At the beginning of the 18th century, the world witnessed a change and progress in many aspects of the industrial fields such as the different means of production .this era is called the industrial revolution which especially appeared in Britain and extended to other areas of the world .it leads to many changes in Europe and participated in different economic, political and cultural and social fields. and it has a very important role in progress and development but its disadvantage is that it is exploited by the capitalists to achieve their special rights .in othe
... Show MoreThis research deals with the study and investigation of the diwan Al_sheikh (Abu Baker Bin Fityan Al_ Arawdaky) dead 672H) . He is one of the Sufism who was born in (Damascus) and lived there all of his life . this biography is limited and his works would not be found except this diwan which oppears on three copies that can be taken from mannscrpt kept in different libraries .
We thought to investigate this diwan in many de partments , but the best one had been chosen according to its completion .
This diwan is special in letters that can be ordered alphabetically , re ferences contain explanation in addition to mention many words and phrase
The super good artist, and its leading role experience detailed instrumental in the birth of the modern Iraqi drawing because of the represented technical personal super good in leading production Iraqi drawing since the early forties. If taken Excellence professional to experience the artist compared to the experiences of other pioneers and strengthened, the stylistic diversity through metaphors Different presented by the super good so that covered the period from romantic to Impressionism through schools drawing expressionism and cubism space, and therefore the heritage and the richness of diversity stylistic high to experience the good represents documentation required by contemporary Iraqi formation history, so the researcher found t
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Studying and considering the text of the holy Quran is a task of necessity which needs a valuable as well as reliable contribution from all the concerned parties because of the greatness of this holy and scared text. The text of the holy Quran