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 organizational culture is an effective control mechanism that dictates the behavior of employees and according to their intellectual and social orientations, so it is considered a more powerful way to control employee orientations and determine their management according to organizational rules and regulations, as it was one of the most important factors determining the performance of organizations, while organizational performance is a measure of what the organization has achieved from the objectives of the scheme To ensure that it faces various changes and remains within the global competition, and to reach that it was necessary to identify the most prominent and most important research problems in knowing the extent of com
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The research aims to reveal the impact of media policy in Iraqi media outlets on the level of objectivity in these outlets. A study from the communicators’ point of view where the researcher used a survey method on the communicators in media outlets to reveal the extent of media policies knowledge as well as the pressures exerted by this policy on communicators in media outlets. It also reveals the extent of their commitment to objectivity, neutrality in dealing with information and the way used to transfer it.
The research sample included (179) respondents from communicators in a range of Media outlets such as (Press, Radio, and Television), The researcher was careful with the diversity of the sample, and
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Due to the increasing interest in the quality of auditing by writers, researchers and regulators of the auditing profession. The matter necessitated a statement of the extent to which the auditor practices professional skepticism, because of its significant impact in discovering errors and material misrepresentations contained in the financial statements in order to give the financial community confidence in them and the success of the audit process. The research aims to clarify the concept and importance of the practice of professional skepticism and its effect on the quality of the auditor's performance in Iraq. To achieve the research objectives, the two re
... Show MoreThe purpose of this paper is to identifying the level of skill self-esteem of the young tennis players in the Governorate of Baghdad, identifying some aspects of attention (acuteness, concentration, and diversion of attention) among the young tennis players of the Baghdad governorate, and identify the skills of serve and serve spiking in tennis by young tennis players in Baghdad governorate. The researchers used the descriptive approach in the correlative relations style for its suitability and the research problem. the research sample was chosen in a deliberate way from the youth team players in tennis for the Governorate of Baghdad and the participants in the 2021-2022 sports season, whose number is (20) male players and (4) young playe
... Show MoreThe objective of this study is to explain the role of credit policies in agricultural development of Iraq during the period 1979-1989 which were represented by the policy of co-operative agricultural bank the organization that responsible to finance agricultural sector for various reasons. It has been shown that there was no clear credit policy existed during the period concerned due to the differences between loans from year. The loan growth rate was low in general comparing with objectives of the agricultural development plans, a low production rates comparing with loans paid, the growth rate of average number of trees in each donum and the growth rate of livestock number was also low.In conclusion there should be a clear plan for cred
... Show MoreNegotiation is considered as one of the most important kinds of communication in the contemporary organizations, which depend on the important role of managerial information systems in providing necessary and suitable information for success of the negotiation process.
Accordingly, this study aims at measuring the extent of the variables effect of managerial information system in the negotiation process.
To achieve this study, two hypotheses were chosen; the first is the correlation relation and the second is the effect, and statistical means represented by correlation coefficient "Spearman" and (R2) were used.
A Number of conclusions were
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The Reasons behind the decadence of the studies concerning the evening school in Salah al Deen A field study
In this paper , some of lexical stylistic , syntactical stylistic devices , and one phonetic stylistic device are going to be illustrated in the study of the aphorisms of “life and death” . These stylistic devices are parallelism , hyperbole , alliteration , meiosis , irony , oxymoron , cliché , litotes , metalepsis , and loose sentences. This paper aims at identifying the functions and the frequencies of these devices. These stylistic devices make one speech and writing more interesting and help to get the attention of readers/ listeners
Landlocked countries are displayed geopolitical new geo-political and intended to
countries that do not have sea views, a phenomenon present in four continents of the world
are: Africa, Europe, and Asia, and South America and the number arrived at the present time
to the (44) state the largest number of them in the continent it arrived in Africa (16) countries
in Asia (13) countries and Europe (13) In the State of South America two. This phenomenon
emerged due to the division of federations and empires and colonial treaties and others. But
the negative effects suffered by these countries may vary from one country to another, since
these countries in the continent of Europe, for example, is different from the same cou