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 world is moving towards greening business in general and production systems in particular. At the same time, economic units seek to enhance their productivity and find any variables that can contribute to improving their elements. Economic units should not ignore the green dimension of cost management techniques because of its role in containing the green dimension of the production system and the product. However the few researches dealt with the subject of the green kaizen showed its role in reducing costs and improving the environment. Those researches did not address its contribution to raising the level of productivity. Productivity is an important indicator of economic units that expresses their level of success and progre
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Gypsum Plaster is an important building materials, and because of the availabilty of its raw materials. In this research the effect of various additives on the properties of plaster was studied , like Polyvinyl Acetate, Furfural, Fumed Silica at different rate of addition and two types of fibers, Carbon Fiber and Polypropylene Fiber to the plaster at a different volumetric rate. It was found that after analysis of the results the use of Furfural as an additive to plaster by 2.5% is the optimum ratio of addition to that it improved the flexural Strength by 3.18%.
When using Polyvinyl Acetate it was found that the ratio of the additive 2% is the optimum ratio of addition to the plaster, because it improved the value of the flexural stre
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Education is the most powerful and important weapon in fighting poverty and unemployment because it provides students with new skills that appropriate the new market requirements and fair distribution of natural resources. It also transfers knowledge, skills, and ethics over generations. Education aims to create effective leaders who go under training and rehabilitation process, create a new human and instill faith, generate the creativity and innovation, and keep abreast with scientific process, updating curriculum, and finally, applying the technical education
This study aims to discuss how English Language Textbook (ELT), used in Iraqi schools, can be developed. All Iraqi teachers in Iraq spend much time using ELT textbooks in classrooms, and most of the Iraqi students depend on these textbooks to learn and improve the English language, so choosing an appropriate ELT textbook is so essential. A suitable book must include critical components that fit teachers' and students' needs. The quality of ELT textbooks has been improved dramatically in recent years, even though these textbooks still do not meet students' needs, especially in language communication skills. This study seeks to investigate the most critical components that may make the ELT textbooks are more influential and interactive for Ir
... Show MoreMedia theories and studies have provided many diligences on the concept of social media and the circle of influence, including the theory of social marketing which deals with how to promote ideas espoused by the elite in a society to become a recognized social value. The emergence of social networks provided a revolutionary breakthrough, taking the media to unprecedented horizons; and giving its users great opportunities to influence and move across borders without restrictions and censorship, except in a relatively limited manner.
So, the emergence of social media has created channels of live broadcasting from its audience in a method of development that changes the essence of the known communication theories; a
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Raising children occupies a prominent place in Islam as a step paving the way for the success of reform projects on the level of diverse human life, and for this reason the recommendation for education was mentioned in the mission entrusted to the Prophet (PBUH), the Almighty said:
(( هُوَ الَّذِي بَعَثَ فِي الْأُمِّيِّينَ رَسُولًا مِّنْهُمْ يَتْلُو عَلَيْهِمْ آيَاتِهِ وَيُزَكِّيهِمْ وَيُعَلِّمُهُمُ الْكِتَابَ وَالْحِكْمَةَ وَإِن كَانُوا مِن قَبْلُ لَفِي ضَلَالٍ مُّبِينٍ)) Jumaa verse /38
The topic of the research that is in your hands deals with the
... Show MoreThe aim of the research is to identify the attitudes of Iraqi youth
towards volunteering work by using the survey method and the scale
tool to identify what young volunteers can carry from the attitudes
towards volunteering work because the phenomenon of volunteer
work is of great importance in society. The scale was applied to
(525) volunteers among Iraqi youth. The research reached a set
of results, the most prominent of which is the existence of positive
trends among young people towards volunteering work, meaning
that Iraqi youth volunteers have awareness of the concept of
volunteering correctly. As for their goals of volunteering, they are
humanitarian and social goals for the advancement of society, an
Receipt date:11/19/2020 acceptance date:10/1/2021 Publishing date:12/31/2021
This work is licensed under a Creative Commons Attribution 4.0 International License.
Human rights are one of the basic concepts of modern and contemporary times, and political thought as the origin of political science and its source of knowledge have impact in this science and its branches
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the mental image is so important in human life as one of the major standers for his trends and behavior, and as the human nature requires to interest in things based on how much it’s close to and how much it effects on his interest, So the neighborhood countries was one of the topics that occupied the attention of the Iraqi individual and pushed him to form perceptions of them based on the cultural heritage and the historical relations of Iraq with these countries as well as the actions of neighboring countries on Iraq and the resulting effects on the course of events. the mental image is so important in human life as one of the major standers for his trends and behavior, and as the human nature requires to interest in things bas
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During the prior three decades numerous research works presented to investigate the behavior of reinforced soil. A, IJSR, Call for Papers, Online Journal