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.
This work was conducted to study the treatment of industrial waste water, and more particularly those in the General Company of Electrical Industries.This waste water, has zinc ion with maximum concentration in solution of 90 ppm.
The reuse of such effluent can be made possible via appropriate treatments, such as chemical coagulation, Na2S is used as coagulant.
The parameters that influenced the waste water treatment are: temperature, pH, dose of coagulant and settling time.
It was found that the best condition for zinc removal, within the range of operation used ,were a temperature of 20C a pH value of 13 , a coagulant dose of 15 g Na2S /400ml solution and a settling time of 7 days. Under these conditions the zinc concentrat
This dissertation explores the role of Iraqi E-press in crystallizing the orientations or directions of the public towards the local political issues like (demonstrations, parliamentarian elections, provincial elections, the public budget and its consequences, Iraq’s relations with neighboring countries, Iraqi HOR and its sessions, and the relation of the federal government with KRG). The dissertation’s main problem revolves around a central inquiry: what is the role of the Iraqi E-press in crystalizing the direction of the Iraqi public towards the local political issues?
The dissertation included a number of assumptions; the first assumes the relation of demographic variants (gender, age, social status, education, working status
The phenomenon of terrorism is one of the most serious challenges facing the world at present. So this concept has occupied a great deal of interest of researchers and scholars in the relevant disciplines. There is no doubt that the study of the concept of terrorism requires a study of its various aspects. However, this study will be limited to knowing the role of television channels in providing the public with information about terrorist events, the extent to which young people rely on these channels to shape their attitudes towards terrorism issues. This study also seeks the relationship between satellite television channels and terrorism based on the relevant media li
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In the midst of the public narrative film , we discussed the issue of dealing with the current narrative more specialized which its future dimension form shift and twist on the level of construction narrative film in some of its diverse and renewable trends in its two ways theoretical and practical and non-give important implications for the modes of operation of the renewable narrative structures and the fact that the cinema is an arts which always open to ideas in neighboring fields and this come naturally as a result of the continuing intellectual and knowledge sharing between cinema and other science . our current research has already begun to address the issue in a stream of consciousness narrative structure film based on all that t
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Length of plasma generated by dc gas discharge under different vacuum pressures was studied experimentally. The cylindrical discharge tube of length 2m was evacuated under vacuum pressure range (0.1-0.5) mbar at constant external working dc voltage 1500V. It was found that the plasma length (L) increased exponentially with increasing of background vacuum air pressure. Empirical equation has been obtained between plasma length and gas pressure by using Logistic model of curve fitting. As vacuum pressure increases the plasma length increases due to collisions, ionizations, and diffusions of electrons and ions.
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This study deals with the role of compensation system in improving the quality of educational services (University of Halabja as a Model) also our problem was the following question ; What is the role of compensation system in its different dimensions in improving the quality of educational services? And what is the relationship and impact of using the dimensions of the compensation system to improve the quality of educational services? The hypothesis of the research included the correlation and the impacts between the compensation system and its combined variables in the quality of educational services. This was proved through a field study and the distribution of questionn
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This research includes problems that facing the philosophy of education in the variables of knowledge and Informatics society (techno _ social).
The problematic research included three questions:
1- What are the concepts and characterization related to the problematic of relationship between the philosophy of education and informatics variables (techno - social).
2-What kind of problems facing speech philosophy of education in the variables information (techno - social)
3 - What are the perceptions of educational proposed to address problematic philosophy of education in the scope of human (human nature) and (values and morals), in addition the research may explain the co
... Show MoreIn this research we present An idea of setting up same split plots experiments in many locations and many periods by Latin Square Design. This cases represents a modest contribution in area of design and analysis of experiments. we had written (theoretically) the general plans, the mathematical models for these experiments, and finding the derivations of EMS for each component (source) of sources of variation of the analysis of variance tables which uses for the statistical analysis for these expirements
The responsibility of the Central Bank through the implementation of its monetary policy to maintain the integrity and stability of the financial system and the economic system, because any shock, whether internal or external, may endanger the financial system and instability, so the research sheds light on the effectiveness of monetary policy in maintaining financial stability, The most important conclusion is that there is an increase in capital, which gives banks the possibility to face the risks to which they are exposed, as well as a rise in the total bad debts, which weakens its financial position, which constitutes a decline in the financial stability of these banks.