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.
أن تكوين المودود شكل (1) فى منطقة الدراسة يعتبر من التكاوين المهمة فى منطقة الخليج العربى وايران . لقد تم وصف هذا التكوين لاول مرة من قبل (1) فى المقطع المثالى فى بئر ( دخان -1 ) والذى قسمة الى قسمين رئيسين . القسم الاعلى يتكون من حجر جيرى حامل للدمالق اما القسم الاسفل فهو صلصالى .
The researchers have a special interest in studying Markov chains as one of the probability samples which has many applications in different fields. This study comes to deal with the changes issue that happen on budget expenditures by using statistical methods, and Markov chains is the best expression about that as they are regarded reliable samples in the prediction process. A transitional matrix is built for three expenditure cases (increase ,decrease ,stability) for one of budget expenditure items (base salary) for three directorates (Baghdad ,Nineveh , Diyala) of one of the ministries. Results are analyzed by applying Maximum likelihood estimation and Ordinary least squares methods resulting
... Show Moreيمكن القول ، أن أزمة الاستبعاد والخلاف بشان ولاية العهد شهدت ولادة النظام الحزبي الحديث في إنكلترا، واظهرت حالة جديدة للتنظيم والدعاية الحزبية وادخال طرق جديدة للتأثير في الرأي العام في اثناء الانتخابات، واختلفت تلك الاحزاب في ايديولوجياتها فحزب الويك كانت له ارتباطات دينية بين اعضائه مع البيورتان أذ تشاركوا في مفاهيم حرية التعبير عن الرأي ومقاومة هيمنة رجال الكنيسة المتنفذين، في حين كان حزب التور
... Show MoreThe poetic necessity in evidence to explain Ibn Aqeel were not alike, came a statement from him as a necessity in some verses and the other came as abnormal, differentiating it from the language, but he never mentioned in some verses in which the need as a necessity,
The development of information systems in recent years has contributed to various methods of gathering information to evaluate IS performance. The most common approach used to collect information is called the survey system. This method, however, suffers one major drawback. The decision makers consume considerable time to transform data from survey sheets to analytical programs. As such, this paper proposes a method called ‘survey algorithm based on R programming language’ or SABR, for data transformation from the survey sheets inside R environments by treating the arrangement of data as a relational format. R and Relational data format provide excellent opportunity to manage and analyse the accumulated data. Moreover, a survey syste
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The research seeks to identify the comprehensive electronic banking system and the role of the auditor in light of the customer's application of electronic systems that depend on the Internet in providing its services, as a proposed audit program has been prepared in accordance with international auditing controls and standards based on the study of the customer's environment and the analysis of external and internal risks in the light of financial and non-financial indicators, the research reached a set of conclusions, most notably, increasing the dependence of banks on the comprehensive banking system for its ability to provide new and diverse banking services, The researcher suggested several recommendations, the most important of whi
... Show Moreبعض الملاحظات على القانون رقم 35 لسنة 2007 قانون العمل الصحفي في كوردستان
In the subject area (participation and tandem), the study showed the views of Mr. Sadr in this field when researching first: the issue of the necessity of these two phenomena in the language that some imams of the language and principles called for to discuss and respond to, and
The study (Quality in the Industrial Products Designs and its Reflection on Achieving Competitive Advantage) focused on developing the products in a way that satisfies human desires through the impact of technology on products design systems and performance enhancement. The study question is: how to effectively achieve quality in industrial products designs that influences competitiveness? The aim of the research is to show the design contexts for the product and its reflection on competitiveness. The study is limited to (LG) products in 2017-2018. The results and conclusions reached at by the researcher are included in the study.
The sample models adopted contexts, forms and relational relations transcending traditional contex
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Heart disease is a significant and impactful health condition that ranks as the leading cause of death in many countries. In order to aid physicians in diagnosing cardiovascular diseases, clinical datasets are available for reference. However, with the rise of big data and medical datasets, it has become increasingly challenging for medical practitioners to accurately predict heart disease due to the abundance of unrelated and redundant features that hinder computational complexity and accuracy. As such, this study aims to identify the most discriminative features within high-dimensional datasets while minimizing complexity and improving accuracy through an Extra Tree feature selection based technique. The work study assesses the efficac
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