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.
التنمية المستدامة حق لكل البشرية وأنها مفهوم ٌ مركب من عنصرين هما التنمية واالستدامة مهمين متالصقين أي ال يوجد تنمية دون استدامة وال العكس يصح، وأنها تمتلك العديد دراسات سياسية وإستراتيجية من األهداف ويبرز هدف الـ)القضاء على الفقر، والقضاء على الجوع( ومن أهم أهدافها، هذه الظاهرة بارزة في المجتمع العراقي بسبب الحروب واالزمات المتكررة فيه وحاالت الحصار االقتصادي، وكذلك بسبب عدم توزيع موارده بشكل عادل من قبل
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Sözlü Türk halk edebiyatı ürünleri içinde önemli yere sahip olan türlerden biri de atasözleridir. Atasözleri, nesilden nesile halk ağzında dolaşan, kimin söylediği bilinmeyen, birtakım gerçekleri kısa ve öz bir şekilde ifade eden sözlerdir. Türk atasözleri Orhun Abideleri’nde ilk kez karşımıza çıkmakla birlikte, Uygur dönemi yazıtlarında ve özellikle Dîvânü Lûgati’t Türk’te geniş yer bulmuştur. Dilin anlatım ve kullanım imkânlarını geliştiren atasözlerine, dünyanın bütün dillerinde rastlanabilir. Bunun için, söyleyişte güzel, anlatımda güçlü, kavramda önemli unsurlar içeren kalıplaşmış sözler halinde bulunurlar. Bu çalı
... Show MoreThis research aims to assess the adoption of TQM in the Middle East Bank for Investment, and diagnosis means and techniques of technological innovation that applied in, as well as to determine the nature of the relationship between total quality management practices (operations management, employment relations, customer relations) and technological innovation (the incremental innovation of the service, incremental innovation process, a radical innovation of the service, a radical innovation of the operation), through use the checklists, derived from a study (Kim et al, 2012) the many styles of mathematical and statistical tools was adopted like the percentage, mean, duplicates, as well as the adoption of the Z test th
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Research problem: the problem of the current research can determine the dimensions of answering the following question - What is the impact of the use strategy summaries tribal collection and retention in the second grade students in the middle of history?
The importance of research: In order to achieve the desired education and access to educational goals required, and to address all the challenges facing the educational process, so you may need to use methods and different educational methods in the teaching of social history, particularly, of those methods and modalities to adopt strategies tribal in teaching, has chosen researcher summaries tribal style, which is one of the strategies of goo
Abstract:
Objective: To know the effect of televised media violence on the relationship of Children's primary school with mates and identify association between the demographic characteristics and socioeconomic status for primary school children and their relation with exposure to televised violence media.
Methodology: simple probability sample of 221 children were selected from 1425 children are learning in schools in Al-Nasiriyah City.
Results: Results of the current study showed that (53.8%) of children exposed to Televised media violence be relationship with their mates weak, (46.2%) of them have their relationship with their mates good, as well as the study showed that the presence significant correlation with males genders
Photonic Crystal Fiber Interferometers (PCFIs) are widely used for sensing applications. This work presents the fabrication and the characterization of a relative humidity sensor based on a polymer-coated photonic crystal fiber that operates in a Mach- Zehnder Interferometer (MZI) transmission mode. The fabrication of the sensor involved splicing a short (1 cm) length of Photonic Crystal Fiber (PCF) between two single-mode fibers (SMF). It was then coated with a layer of agarose solution. Experimental results showed that a high humidity sensitivity of 29.37 pm/%RH was achieved within a measurement range of 27–95%RH. The sensor also showed good repeatability, small size, measurement accuracy and wide humidity range. The RH sensitivity o
... Show Moreهدفت هذه الدراسة إلى مقارنة أثر أسلوب التعلم التعاوني بالأسلوب التقليدي في التحصيل الدراسي، وعلاقته بالاتجاه نحو الحاسب الآلي عند طلبة كلية التربية بجامعة بغداد خلال دراستهم لمقرر الحاسب الآلي وقد تضمنت إجراءات الدراسة استخدام الأسلوب التجريبي، وذلك بتوزيع أربع شعب دراسية على مجموعتين: "مجموعة تجريبية" يتم تدريسها باستخدام أسلوب التعلم التعاوني، والمجموعة الثانية: "مجموعة ضابطة" يتم تدريسها بالطريق
... Show MoreSweet pepper (Capsicum annuum L.) is an economically important vegetable crop. Wilt disease caused by Fusarium oxysporum f. sp. capsici is a specific pathogen that affects the pepper. Four isolates of F. oxysporum f. sp. capsici Fo3, Fo6, Fo7 and Fo8 were obtained from diseased pepper plants that were collected from different pepper fields in Baghdad. Fo6 isolate that has high pathogenicity to pepper seeds, Trichoderma harzianum (Th) was tested in vitro against F. oxysporum f. sp. capsici showed a high inhibition rate for the isolate Fo6, the concentration of chelated iron Fe-EDDHA 0.5% reduced the radial growth of Fo6 whi
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In this work the effect of choosing tri-circular tube section had been addressed to minimize the end effector’s error, a comparison had been made between the tri-tube section and the traditional square cross section for a robot arm, the study shows that for the same weight of square section and tri-tube section the error may be reduced by about 33%.
A program had been built up by the use of MathCAD software to calculate the minimum weight of a square section robot arm that could with stand a given pay load and gives a minimum deflection. The second part of the program makes an optimization process for the dimension of the cross section and gives the dimensions of the tri-circular tube cross section that have the same weight of
... Show Moreلقد أدت التطورات العلمية والتقنية وتطبيقاتها العملية في مختلف ميادين الحياة بشكل عام وميدان التربية والتعليم بشكل خاص إلى ظهور تغيرات في البناء التعليمي وطرائق التدريس بصيغتها الحديثة التي تنسجم في مجملها وروح العصر مما دعى المؤسسات التربوية والتعليمية وبإيعاز إلى الباحثين والمهتمين بهذا الميدان الى ضرورة متابعة الاتجاهات الحديثة ونواحي التجديد لمحتوى العملية التعليمية فيما يتعلق بالمجالات المعر
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