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.
An oil spill is a leakage of pipelines, vessels, oil rigs, or tankers that leads to the release of petroleum products into the marine environment or on land that happened naturally or due to human action, which resulted in severe damages and financial loss. Satellite imagery is one of the powerful tools currently utilized for capturing and getting vital information from the Earth's surface. But the complexity and the vast amount of data make it challenging and time-consuming for humans to process. However, with the advancement of deep learning techniques, the processes are now computerized for finding vital information using real-time satellite images. This paper applied three deep-learning algorithms for satellite image classification
... Show More
(11)
(8)
It may say that of difference towards a state that had witnessed the birth of modern party system in England ،and it appear a new case of organization and use ways effecting in general opinion through the election parties that had different in their ideology as Alweel party which dealt with religion related among its members with Buretan with its members participation understandings of free expression of their opinions trying to fight the control of Christ men in a time that Tory party was Enklikanian more than as it was loyalty one .
اطروحة ازمة كشمير واثرها على العلاقات الهندية - الباكستانية
هدفت الدراسة الى تحليل محتوى كتاب الرياضيات للصف الاول متوسط على وفق مكونات المعرفة الرياضية (المفاهيم الرياضية , التعميمات الرياضية, المهارات الرياضية والمسائل الرياضية )
وتفرعت منه الاسئلة الاتية :
مانسبة المفاهيم الرياضية المتضمنة في كل فصل من فصول كتاب الرياضيات للصف الاول متوسط وللكتاب ككل ؟
مانسبة المهارات الرياضية المتضمنة في كل فص
... Show MoreThe research aims to identify the level of functional engagement and hope-based thinking of kindergarten teachers, identify if there is a significant difference in functional engagement and hope-based thinking in terms of specialization and years of service for kindergarten teachers, identify if there is a significant correlation between functional engagement and hope-based thinking of kindergarten teachers. The current research is determined by kindergarten teachers in the Second Rusafa Baghdad Education Directorate for the academic year (2022-2023). In order to achieve the objectives of the research, the researcher prepared a functional engagement scale, which consists of (45) items in three areas: Perceptual and functional engagement
... Show Moreيعد موضوع البرنامج النووي الايراني من الموضوعات التي تحظى بأهمية كبيرة في مجال الدراسات الدولية بشكل عام والدراسات الاستراتيجية بشكل خاص، وذلك لكونه لا يتعلق بمستقبل الجمهورية الاسلامية الايرانية فحسب بل بمستقبل منطقة الشرق الاوسط ولاسيما منطقة الخليج العربي، وهو ذو صله وثيقة بمستقبل انتشار الاسلحة النووية بين دول المنطقة والذي قد يؤدي انتشارها الى حروب اقليمية وقد يوظف فيها هذا النوع من الاسلحة النووية،
... Show MoreSome great families in England had competed for the sake of getting authority and power in England.
This competition turned to be a bloody civil war which extended till 1455 and ended with the victory of Henry Tudor whose judgment in England started from 28th of August 1458, consequently a new dynast which is known as (the Tudor)has established
يعد الدين من أكثر المتغيرات تأثيرا في سلوك البشر بصورة عامة ، وفي شخصياتهم وصحتهم النفسية بصورة خاصة .
ولأحداث الحياة والأزمات والشدائد تأثيرها الكبير في هذا المتغير وفي مدى تمسك الناس بقيمهم الدينية .
وفي العراق ، لا تخفى علينا المآسي والأزمات والشدائد التي مر ويمر بها البلد مما قد يزعزع ثقة الناس بمعتقداتهم وقيمهم ، ومن جانب آخر فان دخول المحت
... Show MoreTo maintain a sustained competitive position in the contemporary environment of knowledge economy, organizations as an open social systems must have an ability to learn and know how to adapt to rapid changes in a proper fashion so that organizational objectives will be achieved efficiently and effectively. A multilevel approach is adopted proposing that organizational learning suffers from the lack of interest about the strategic competitive performance of the organization. This remains implicit almost in all models of organizational learning and there is little focus on how learning organizations achieve sustainable competitive advantage . A dynamic model that captures t
... Show More
اثر بديع الزمان سعيد النورسي على الفكر الاسلامي المعاصر في تركيا