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.
Television contributes children the acquisition of knowledge, moral and social values through programs that are offered to them and the extent of the focus on the effective aspects of life in the age of the target stage. The subject of this research aims to know the children programs in Libya television through a comprehensive analytical study of the program entitled “zihur al-hayat” within the broadcast season from April 1, 2004 to June 30, 2004. It also focuses on trying to identify the Libyan television policy in broadcast educational content through the children's programs in the prevailing political and social conditions during the period of study as well as knowing the opinions of the children's sample under study in Al-Baidhaa
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The research aimed to prepare a measure of job stressors affecting the quality of teaching performance in the College of Physical Education and Sports Sciences at the University of Baghdad, to identify their levels, if any, and the most influential dimensions on the quality of teaching performance within the college’s work environment, as well as the deanship’s ability to help prevent and Alleviating its severity through logical administrative methods, on a scale that includes four dimensions that include (the administrative and financial environment, the organizational environment, the social and humanitarian environment, and the scientific and research environment). The descriptive approach was adopted using the case study met
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The different interactions between cometary tail and solar wind ions are studied in the present paper based on three-dimensional Lax explicit method. The model used in this research is based on the continuity equations describing the cometary tail-solar wind interactions. Three dimensional system was considered in this paper. Simulation of the physical system was achieved using computer code written using Matlab 7.0. The parameters studied here assumed Halley comet type and include the particle density , the particles velocity v, the magnetic field strength B, dynamic pressure p and internal energy E. The results of the present research showed that the interaction near the cometary nucleus is mainly affected by the new ions added to the
... Show MoreA solar cell was manufactured from local materials and was dyed using dyes extracted from different organic plants. The solar cell glass slides were coated with a nano-porous layer of Titanium Oxide and infused with two types of acids, Nitric acid and Acetic acid. The organic dyes were extracted from Pomegranate, Hibiscus, Blackberry and Blue Flowers. They were then tested and a comparison was made for the amount of voltage they generate when exposed to sunlight. Hibiscus sabdariffa extract had the best performance parameters; also Different plants give different levels of voltage.
Electronic banking plays a prominent role in providing the best banking services and upgrading the banking sector for the better, so this study aimed to shed light on the most prominent obstacles that prevent the application of electronic banking in banks operating in the city of Nasiriyah, and in order to achieve this goal the researcher used the descriptive analytical approach And through a questionnaire form that was distributed to a group of employees, numbering (60) employees in the upper, middle and operational departments in a number of branches of private banks operating in the city of Nasiriyah, namely (the Iraqi Trade Bank, the Gulf Commercial Bank, the Bank of Baghdad, the Union Bank of Iraq), which represented The stu
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The current research variables have received increasing attention in the recent period because they are one of the important issues affecting the future of organizations, as a result of the speed of environmental variables that have greatly affected organizations and for the purpose of explaining the relationships and links between research variables, as this research presents a test "the type and direction of the relationship between strategic foresight capabilities As an independent variable and green creativity "as a respondent variable. A set of questions has arisen about the basic research problem, including what is the nature and level of interest in the research variables (strategic foresight capabilities an
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The research deals with the concept of rationalization of consumption, which is legitimately legitimized, by indicating the permissibility of consumption and its limits in Islam, the legitimate aspects of spending and its controls, and the concept of development in the Islamic economy. The researcher followed the descriptive method by presenting the legal texts and jurisprudential opinions and linking them to contemporary economic problems.The research has reached several conclusions, the most important of which is that the goal of Islam in relation to consumption is to inform the Muslim of the amount of economic maturity, and the truth of alms is good in money and religion. It is necessary for achieving maturity that both means
... Show MoreNonlinear diffraction pattern can be induced by focusing CW
laser into a thin quartzes cuvette containing nanofluid. The number
of revealed pattern rings indicates to the nonlinear behavior of fluid.
Here, the nonlinear refractive index of each of functionalized single
wall carbon nanotube (F-SWCNTs) suspention and multi wall carbon
nanotube (F-MWCNTs) suspention have been investigated
experimentally .Each of CNTs suspention was at volume fraction of
13×10−5 and 6×10−5. Moreover the laser source at wavelength of
473 nm was used. The results show that SWCNTs suspention
possesses higher nonlinearty than other at the same volume fraction
The chemical additives used to enhance the properties of drilling mud cause damage to humans and the environment. Therefore, it is necessary to search for alternative additives to add them to the drilling mud. Thus, this study investigates the effects of pomegranate peel and grape seed powders as natural waste when added to un-weighted water-based mud. The test includes measurements of the rheological properties and filtration, as well as the alkanity and density of the drilling mud. The results showed a decrease in PH values with an increase in the concentrations of pomegranate peel or grapeseed, and a decrease in mud density with an increase in powders of pomegranate peel and grape seed concentrations that resulted f
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