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 Audit evedances represent the reconciliation tools between the Financial data shown on financial statements, and the level of satisfaction level of the Auditor about these statements. According that, the Auditor try to achieve the highest quantity of These evidances, and the most satisfactive of it…, but that will be so hard sometimes, when the internal controlling system is not good, and when the Auditor had some satisfied evidences, but not sharp… So, this research comes to inspect the relation between the quantity, and the level of satisfaction, and argument to prove that evidences gives. This research assumes that getting enough evidences leads to reduce faults, improves the auditing operation, and avoids risks. The research
... Show More
The issue of measurement of operational efficiency and productivity plays a major role in determining the weakness of the company, especially in relation to the productive processes, and thus starting to address these points and improve their performance. Hence the problem of research on how to determine the constraints in the production process, to identify weaknesses in the company. The research aims to clarify the role of throughput accounting in measuring the operational efficiency of the company in addition to clarify some of the constraints and causes behind them. The study concluded a set of conclusions, the most important of which is the availability of throughput accounting indicators that help in measuring operational efficienc
... Show More
(1)
Abstract:
This research to monitor the features of the historical method in the
thought of a linguistic scientist is known (ibin genieD. 392 AH by offering a
range of grammatical rules presented in his book (the properties and the
nature of their treatment on the basis of the historical method in accordance
with These are an important milestone in facilitating the grammatical rules and
display image "makes it more suitable for the social reality
This study aims to find out the effectiveness of a cognitive-behavioral counseling program in enhancing self-management in reducing the academic procrastination of tenth-grade male students. The sample consisted of (26) male students divided into an experimental group of (13) students and a control group of (13) students. Two scales of self-management and academic procrastination were used, prepared by the researcher. The counseling program was prepared by the researcher. The results showed the program's effectiveness in enhancing self-management and reducing academic procrastination in the posttest, as it showed the continuation of this enhancement in self-management and the increase in the reduction of procrastination in the follow-up
... Show MoreThe research aims to identify the theoretical framework of technical reserves in the insurance activity and the role of the auditor in verifying the integrity of the estimates of technical provisions (technical reserves) for the branches of general insurance in insurance companies based on the relevant international auditing standards, as a proposed audit program has been prepared in accordance with international auditing standards that enable the auditor to express a sound opinion on the fairness of the financial statements of these companies , The research has reached many conclusions, the most important of which is the existence of deficiencies in the audit procedures of insurance companies, as the audit program of those companies did
... Show MoreThe research aimed to identify "the effectiveness of educational-learning design according to the model of brain compatibility in achievement among firstmiddle grade students in mathematics", in schools affiliated with the Second Karkh Directorate of Education. To achieve the goal of research, the following zero hypothesis has been formulated: " There is no statistically significant difference at the semantic level (05.0) between the average scores of experimental group students who will study with design accreditation (educational - learning) according to the brain compatibility model and the grades of control group students who will study in the usual way in the achievement thinking test". The research community, which is represented by
... Show MoreThis study aimed to identify the perceived mental image of volunteering, and its relationship to volunteer motivation among a sample of Al-Quds Open University students, as well as to identify the differences in the perceived mental image of volunteering due to variables (gender, year of study, place of residence, college). The researcher has used relational descriptive approach. The researcher has used two questionnaires, the first was used to measure the perceptive mental image of volunteering, and the second to measure the motivation towards volunteering, and the study population may consist of all students of Al-Quds Open University Hebron Branch during the first semester of the academic year 2021/2020 and their number (3462)Male and
... Show MoreThe aim of the current study is to create special norms of the second edition of Minnesota multi faces personality inventory, and the fifth edition of the sixteen personality factor questionnaire of catel. To this end, the researcher applied the Minnesota multi faces personality inventory over a sample of (1646) secondary and university students as well as plenty of disorders. She also applied the sixteen personality factor questionnaire of catel on (4700) secondary and university students. SPSS tools were used to process data.