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.
Abstract
The study aims to find out the impact of expectations and perceptions in determining the position of the customer service quality received by him. Represent the expectations and perceptions customer’s key of service quality determinants. The customer's requirements and needs main pivot, who must be built all events and activities and efforts of service organizations, including the hotel and organizations that operate in an environment known as highly competitive , intensification and complexity of the conditions set by the customer and increasing day after day. The study sample of three Luxury hotels in Kurdistan region of Iraq a model. The use of service quality m
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The present study is a qualitative study that aims to investigate the way the Iraqi caricaturist,Dheaa Al-Hajjar uses caricatures to produce a satirical meaning humorously.Producing satire while at the same maintaining humor requires a creative thinking on the part of the caricaturist. Thus, the study examines the production of humorous satire in terms of creativity. The analysis is done from the cognitive linguistic point of view using Arthur Koestler's theory of bisociation as presented in his book The Act of Creation in 1964. The main principle on which the theory is based is that humor is created via linking (or bisociating in Koestler's terms) two habitually incompatible trains of thought in order to come up with a novel me
... Show MoreThe research (The Aesthetics of Lumia Art in Contemporary Textile Arts: An Analytical Study) included four chapters, the first to explain the research problem summarized by the question: Does the art of Lumia achieve aesthetic values in contemporary textile arts?, and aims to: Identify the aesthetics of Lumia art and its applied uses in contemporary textile arts, within the time period (2013-2022). The third chapter included: research procedures and sample analysis (4) models according to the descriptive analytical approach, and the fourth chapter dealt with: results, conclusions and recommendations as well as sources.
That communication between people is not only through speech but includes other images of the most important body inspiration. And that the Koran worked on the diversity of ways in which the meanings of the hearer and did not stop at the limit of speech, but included situations where the use of body inspiration and indicate its importance in communication. However, signals and organ movements play a major role in the process of communication between people. Facial and hands movements play an important role in the communication process as they are a tool for communicating ideas to others.
After its 35-year occupation of Japan and the US occupation, Korea has set its sights on a long-term goal of building its country and establishing its foundations, unobtrusive and unchecked by the problems and wars that have stood in the way of its goal, surpassing all odds and achieving the best results. The most powerful Asian and global economies, which gained the respect of the world and its appreciation of the experience has become referred to as boys
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In this paper, magnesium oxide nanoparticles (MgO NPS) have been prepared and characterized and its concentration effect has been studied on polymers surface (MgO NPS). The results showed that the degradation of poly methyl methacrylate increased when using such metal oxide. The results also showed that the metal oxide increased the degradation of poly methyl methacrylate. X-ray diffraction, scanning electron microscopy, atomic force microscopy were used to study the morphological characteristics and size of nano MgO particles analysis. Films were prepared by mixing the different masses of MgO NPS (0.025, 0.05, 0.1, 0.2 and 0.4) % with a polymer solution ratio (W/V) 7 %. Photo-
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While providing important news information, News tickers ( also called sliders or crawlers ) have become one of the methods used daily by satellite channels, because it’s almost a continuous news coverage and as it seems, it has become today an addition to the news world. Hence, satellite channels need to look for a mechanism to build news tickers in order to develop them even though they are still today not recognisable and in need of being classified in a radio or television art, and that is not easy. This research sheds light on the construction of the slider of a news satellite channel, which is important according to our modest convictions, as it can be the beginning of a long scientific research in a new field of study. The probl
... Show MoreThe present work aimed to examine the nature and degree of the cross-correlations among three different ionospheric indices: these are Optimum Working Frequency (OWF), Highest Probable Frequency (HPF), and Best Usable Frequency (BUF). VOCAP and ASASPS models were adopted to determine the datasets of the selected ionospheric indices. The determination was made for different transceiver stations that provide certain HF connection links during the minimum and maximum years of solar cycle 24, 2009 and 2014, respectively. Matlab program was implemented to produce the geodesic parameters for the selected transceiver stations. The determination was made for different path lengths (500, 1000, 1500, and 2000) Km and bearings (0o, 45
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(Social values) are of great importance in the lives of nations and peoples as they are the frame of reference that governs the relations of members of society to each other and regulates their life affairs.
And the Prophet of Islam (may God’s prayers and peace be upon him) has told about a group of (social values) such as: spreading peace, feeding food, being fair in dealing with others, and clarifying what a Muslim should have towards his Muslim brother from the safety of the chest and refraining from harming him with the tongue and hand, and so on. Ethics and behaviors that are directly and closely related to (social values).
The best book that abounds with these (social valu
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