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.
Discussion dealt with the independent factors critical such us success factors and the risk management process, and dependent factor of the general competitive strategies, and began searching the dilemma of thought, as crystallized his problem in the light of the need for organizations to philosophy and deeper vision of a more comprehensive understanding of the concept of risk management, assessment and management to maximize the competitive strategies of public, and on this basis, Search queries formulated problem of the gap between the knowledge-based intellectual propositions farcical for the purposes of interpretation of the relationship between the critical success factors and the risk
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Background: One of the most prevalent procedures in oral surgery is the removal of impacted mandibular third molars, typically accompanied by trismus, edema, and pain. Several methods and biomaterials were implemented to mitigate or avoid these surgical problems. Objectives: To evaluate the efficiency of chlorhexidine gel (WISDOM®) in minimizing postoperative sequelae associated with the impacted mandibular third molar that will be surgically extracted and its role in promoting early soft tissue closure of the surgical site. Methods: The study design was a double-masked and randomized, controlled clinical study that included healthy patients needing the removal of a mandibular third molar through surgery. The participants were rand
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The goal of current research to:1 - Know when aesthetic implications (Korchh)2 - To form the structure of systemic indicators and results that reflect the visions of intellectual, philosophical and aesthetic art for this study.The theoretical framework for the study of the search for the meaning of beauty, definition ( Krochh) being a philosopher, his views, his own aesthetic philosophy, knowledge, art and beauty, as well as a subject of artistic and aesthetic taste and Study in Art Education.The goals have been achieved during the search of Investigation theoretical framework for the search, which tried (INT) to form a clear vision check the second goal by the indicators reached.In light of this, the researcher recommended the need for
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The problem of Multicollinearity is one of the most common problems, which deal to a large extent with the internal correlation between explanatory variables. This problem is especially Appear in economics and applied research, The problem of Multicollinearity has a negative effect on the regression model, such as oversized variance degree and estimation of parameters that are unstable when we use the Least Square Method ( OLS), Therefore, other methods were used to estimate the parameters of the negative binomial model, including the estimated Ridge Regression Method and the Liu type estimator, The negative binomial regression model is a nonline
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The research aims Modifying the accuracy test for the diagonal and straight high smash skill from center (4) according to the body position of the Premier League volleyball players and extracting the grades and standard levels. To achieve the two objectives of the research: the descriptive approach with the survey method was adopted, because it agrees in solving the research problem. As for the research sample, it consisted Of the players in the Premier League for volleyball clubs for the 2023-2024 season, the researcher chose central players (4)(2) because their skill abilities are compatible with the skill of hitting the diagonal and straight smashes, and they numbered (90) players (6 players from each team), and then the researche
... Show MoreThe purpose of the current research is to identify the reality and applicability of the entrepreneurial approach in its dimensions (creative, proactive, independent, risk tolerant, offensive) and its impact on the success factors of the project (organizational commitment, communication, project team, project monitoring) Access to information, treatment, storage), which is a significant and important link in the success and development of industrial projects with the possibility of studying and analyzing the provision of the appropriate environment for this.
the research started from a problem expressed by a number of intellectual and practical questions aimed at answering them as well as To answer a
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ولاء طارق حميد, Mustansiriyah Journal of Sports Science, 2021
This research deals with the risks of non-compliance and its impact on the profitability of Islamic banks. Research variables were measured and analyzed as the risk of non-compliance as an independent variableand profitability as a dependent variable. The profitability was measured by three indicators ((rate of return on assets, rate of return on equity and rate of return on Total deposits)) The results of the research showed a significant relationship between the risk of non-compliance and the rate of return on assets and rate of return on total deposits, while there was no relationship between the risk of non-compliance and rate of return on ownership. The research recommended that the senior management of the Islamic Investment Bank s
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الحقوق والحريات السياسية " دراسة مقارنة بين المواثيق الدولية والشريعة الاسلامية"
Language is a gift from God to His servants, as it is a tool of communication, rather it is a tool of life, and without it, life cannot be straight and complete.
A language is a kind of substitution. A vocal disorder that may be a disease of speech, and it is one of the obstacles caused by organic and congenital causes, perhaps the common one is genetic.If we separate between lisping in children and separating it from what happens in adults, we find that lisping in children may have psychological causes as well as other ones, this is what we will show in this research.
Key words: psychological factor,lisps,children,vocal study .