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 concept of quality of auditing profession comes on top of the concerns of the international business community and international institutions particularly now following the impact of the several failures and financial hardships suffered by the major companies in the recent collapse of money markets in some countries of the world and fear of their recurrence in the future.An observer of the local and international rules and standards (or principles) finds that these include such implications have direct or indirect effects on the performance of the service of the accountant and auditor, which should upgrade their professional performance in these services to a high level of quality so as to be in line with the requirements, principles
... Show MoreLuqman's story stated that human instinct, if I was brought up properly, reaches wisdom and inflicts the right to everything. It is to go to worship God and adhere to the satisfaction of morals and high morals that are ordered to meet among human beings in this life, because this worship educates in the soul the most beautiful morals needed by human beings of honesty, honesty and modesty, and the work of good and virtues, and distancing the soul from evil and vices.
Abstract
Epidemics that afflict humankind are descending renewed, plaguing them in the place and time they spread.
- The epidemic affects individuals and the movement of societies, and its treatment requires dealing with it according to Sharia, taking into account the current data and developments.
- Integrative jurisprudence: it is intended to know the practical legal rulings deduced from the combination of evidence of two or more sciences related to one topic related to it, and among these calamities is the Corona Covid-19 pandemic.
- It is permissible to use sterile materials that contain a percentage of alcohol in sterilizing hands and fogging places, including mosques.
T
... Show MoreThe Iraqi economy has suffered for a long period of inflation because of the Iraq war and the resolutions and the sanctions that were imposed on Iraq, this phenomenon overshadowed at various aspects of the economy including the tax revenue that the State seeks to optimize the total income for the budget, the research covers the years 1990-2010, these years have been divided according to the country's economic variables.
The research adopted on econometrics analysis that is based on the information and data available on topics and has been using statistical methods to test functions are formulated.
Research concluded that rates of inflation and GDP impact is limited to direct taxation and indirect in current prices a
... Show MoreThe military presence in the Gulf region after the British withdrawal from it in 1971 was one of the most important pillars of the American strategy to climb the ladder of global leadership, as the geostrategic features that the region enjoyed provided factors of controlling energy sources and global trade routes. The United States of America guarantees Western Europe and Japan the process of access to energy sources and the exclusion of its opponents from the region, especially the Soviet Union, and the growing American military presence in the Gulf after the invasion of Iraq in 2003. On the other hand, the region experiences many contradictions, some of which threaten its security, such as the exacerbation of disputes between its count
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Urban planning task and the control of constructional planning and urban management for cities considers the main tasks that the government takes care off. The paper discusses the concept of power from historical view of ancient Islamic cities to discover the strategies of urban management that the Islamic city adopt and to employ it in contemporary cities ,the more problems that modern cities suffer from which appears through poorness of urban context ,belongs to the loss of balance exists between the different faces of power that takes the tasks of urban management .therefore enhancement of urban environment is being through re-back that balance in administrative structures that make the cities go ahead . So the attention has b
... Show MoreGaining the relationship between the central government and local governments is great importance especially after the expanded functions of the central government and became unable to carry out their works without all that delegate or transfer parts of its powers to lower levels.
The aims of the research is to determine the relationship of the central government with the local government in accordance with the principle of administrative decentralization with the presentation of the competent authorities, the control of local governments, according to the Provincial Council Act No. 21 of 2008 amended.
The research has a problem that has been the relationship of the central
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The development of a future mechanism for sustainable development in Iraq to meet the current and future challenges requires an analysis of the indicators of sustainable development. This research aims at presenting and analyzing the social care aspect and highlighting the important role of taxes with a focus on social sustainable development to determine the extent and direction of changes. Level of progress, the researcher concludes the weakness of the financial allocations to the Ministry of Labor and Social Affairs and in line with the large number of people who apply the conditions and controls, and recommends the researcher the necessity of participation of all segments of society between the public and private sector In terms of o
... Show MoreThis research deal the primary and secondary sedimentary structures in the By Hassan Formation in the three locations in the northeast of Iraq. Can be recognize many geological structures such as cross bedding, planer bedding, graded bedding, channel structure and mud ball house deposit in the flood plain. The ether side this research study the direction of old current and sedimentary structure that made by the one direction current