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.
Abstract:
The aim of the current study was to investigate the possible protective effect of graded doses (5, 10, and 15mg/kg) of pyridoxine hydrochloride intraperitoneally injected against (15mg/kg) doxorubicin-induced cardiotoxicity in female rats. Fifty-six (56) Wistar albino female rats were utilized weighing 180-200 gm allocated into eight groups, seven rats each; Group I: negative control distilled water; Group II: Pyridoxine (5mg/kg); Group III: Pyridoxine (10mg/kg); Group IV: Pyridoxine (15mg/kg); Group V: doxorubicin (15 mg/kg); Group VI: Pyridoxine (5 mg/kg) prior to
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Geomorphology is concerned with the topographic units that make up the Earth's surface. These take many forms, such as mountains and rivers, and include many dangers such as landslides, landslides and erosion. Many studies appeared in this field to analyze its effects and risks resulting from it, including urban studies, to determine the trends of optimal urban expansion and its geomorphological interactions. The results showed that the city of Kut originated and expanded near the course of the Tigris River and its branches, and it suffers from unbalanced urban expansion, due to the high rate of population growth, and overcrowding in housing units with the growth of urban land uses in it, which prompted the city to extend horizontally and v
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The study aims to measure the level of academic stress in the e-learning environment in three areas, students and their dealing with classmates, dealing with the professor and technical skills, and the nature and content of the curriculum among graduate students in the College of Education at King Khalid University during COVID-19 pandemic. This study was descriptive in nature (survey, comparative). The sample consisted of (512) male and female graduate students in the master's and doctoral programs. The Academic Stress Scale in the E-learning Environment designed by Amer (2021) was used. The results indicated a high level of academic stress among graduate students in the e-learning environment. The study also found that there were stati
... Show MoreThe present paper sheds light on the psychological structure of Simha Bin Zion’s A Broken Soul. After reviewing the biography of the storyteller, it is clear that the hero of the rebellious character in the story of (A Broken Soul) is the writer himself. The storyteller directly begins to depict his psychological sufferings in his childhood days. He tells a story full of sadness and refusal of the neglect he suffered in his childhood. It is obvious that the early five years of Samha bin Zion’s life is considered a period of conflict that participated in the formation of his individual identity. The story represents an outlet for a hidden secret world buried under the layers of his consciousness. It deals with
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The studies on unbonded post-tensioned concrete members strengthened with Carbon Fiber Reinforced Polymers (CFRPs) are limited and the effect of strengthening on the strain of unbonded pre-stressed steel is not well characterized. Estimating the flexural capacity of unbound post-tensioned members using the design methodology specified in the design guidelines for FRP strengthening techniques of bonded post-tensioned members does not provide a reliable evaluation. This study investigates the behavior of unbonded post-tensioned concrete members with partial strand damage (14.3% and 28.6% damage) and strengthened with CFRP laminates using a near-surface mounted technique with and without U-wrap anchorages. The experimental results show
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This article presents and explores the theoretical aspect in the use of Arab Islamic theme by the western writers to obtain and achieve individual motives. In this study the model for the theory of Arab presence in Andalusia , through the book entitled “ Alhamra” by the English writer Washington Erving ,was analyzed.
The most important results in this research: the success of the author in the employment of the Islamic history in the formation of the first American legend, Columbus legend, through the selection of the right thoughts to establish his American National theory. The author compared between the Andalusia experience and the Arab occupation to Spain and the American conquest of the new
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Experience the Islamic financial industry faces many challenges, most notably the lack of proper risk management tools that meet the requirements of legality and economic efficiency advantage from another side, so it requires the search for innovative ways to manage the risk of Islamic banking, Islamic finance industry is manufacture up-to-date, if compared with the financial industry (traditional), which increases the problematic of risk management in the Islamic financial industry nature of treatment which should be compatible with Islamic law, as well as economic efficiency, thereby Progress came the importance of research to highlight the entrance to Islamic financial engineering and the goals sought to be achieved through the use of
... Show MoreThe study was conducted over the period of Oct 2018 to Apr 2019 and is aimed for the detection and estimation of four hazardous Volatile Organic Compounds VOC (benzene, toluene, ethylbenzene, and xylene) so-called (BTEX) in samples collected from the produced water in the Al-Ahdab oil field in Iraq also to track their availability in the important natural water sources around the field. These compounds pose a risk to human health as well as environment. To avoid the laborious and tiresome conventional extraction methods, water samples were collected and concentrated using solid-phase extraction technique (SPE) which is a robust and cost-effective method of sample extraction with minimal exposure and handling of solvents and then to be analy
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Data of multispectral satellite image (Landsat- 5 and Landsat-7) was used to monitoring the case of study area in the agricultural (extension and plant density), using ArcGIS program by the method of analysis (Soil adjusted vegetative Index). The data covers the selected area at west of Baghdad Government with a part of the Anbar and Karbala Government. Satellite image taken during the years 1990, 2001 and 2007. The scene of Satellite Image is consists of seven of spectral band for each satellite, Landsat-5(TM) thematic mapper for the year 1990, as well as satellite Landsat-7 (ETM+) Enhancement thematic mapper for the year 2001 and 2007. The results showed that in the period from 1990 to 2001 decreased land area exposed (bare) and increased
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This research deals with studying and analysis of a poetic group under the
title (Trees behind fence) of the great poet Dr. Ahmed Sulaiman AlAhmed
who is the some of the Shek , Sulaiman Al-Ahmed who is the linguist - poet
and famous jurist member in the Arabic scientific assemble in Damascus and
brother of the great poet Badawi Al-Jabal. This poetic group include two big
poetic legends : the first one is (Trees behind fence , ) which include one
hundred and eighty four line and the second one ( AZ-Mebadia ) which is
consists of one hundred and seventy eight line, both of them from the (Al-
Camil ) meter which is free rhyme which bears a many meaning and pictures
and just the great poet composite the