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Performance Analysis of Four Conceptual Designs for the Air Based Photovoltaic / Thermal Collectors
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The  thermal  and  electrical  performance  of  different  designs  of  air  based  hybrid photovoltaic/thermal collectors is investigated experimentally and theoretically. The circulating air is used to cool PV panels and to collect the absorbed energy to improve their performance. Four different collectors have been designed, manufactured and instrumented namely; double PV panels without cooling (model I), single duct double pass collector (model II), double duct single pass (model III), and single duct single pass (model IV) . Each collector consists of: channel duct, glass cover, axial fan to circulate air and two PV panel in parallel connection. The temperature of the upper and lower surfaces of PV panels, air temperature, air flow rate, air pressure drop, wind speed, solar radiation and ambient temperature were measured. The power produced by solar cells is measured also. A theoretical model has been developed for the collector model IV based on energy balance principle. The prediction of the thermal and hydraulic performance was obtained for the fourth model of PV/T collector by developing a Matlab computer program to solve the numerical model. The experimental results show that the combined efficiency of model III is higher than that of models II and IV. The pressure drop of model III is less than that of models I and IV, by (43.67% and 49%). The average percentage error between the theoretical and experimental results was 9.67%.

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Publication Date
Fri Jan 01 2021
Journal Name
دراسات قانونية
The Legal Nature of the Build-Operate- transfer-Ownership Contract (B.O.T.)
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The legal nature of the Build-Operate-Transfer-Ownership Contract (B.O.T) The Build, Operate, and Transfer of Ownership Contract (BOT) has emerged as the most successful and safest method for involving the private sector in public sector services. The major infrastructure projects that are built through the BOT contract are no longer financed by the state and its budget, but the private sector has played a major role in financing These projects, especially developing countries that need to establish infrastructure or modernize their existing infrastructure, especially in the areas of transport, communications, services, electricity, water ..... and other public utilities.

Publication Date
Sun Jun 01 2014
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The impact of tax reform to increase the federal budget revenues
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The percentage contribution of tax revenue in the federal budget is verysmall compared with the revenue earned from oil revenues, as the dependenceon oil revenues mainly to finance the state budget, have a negative impact onthe national economy as it makes it a one-sided and prisoner of on revenue, thatis the revenue derived from oil which is unstable revenue for continuouschanging in the price of oil The oil revenues reached to (85.4%) in 2009 withpercentage (93.11%) in 2013, The research objective is to study the possibilityof increasing tax revenues in order to raise the proportion of its contribution infinancing the federal budget through effective tax reforms, The mainconclusion of the research is
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Publication Date
Sun Oct 21 2018
Journal Name
Iraqi Journal Of Physics
A simple voice communication using the modulation of the reflected light
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There is no adopt in the importance of the optical communications in scientific civil and military applications because of it’s simplicity in manufacturing and it's low cost. The method of optical communication depends upon bearing the light beam the translated informations by a method called the light modulation. This method depends upon changing some light properties as frequency, amplitude and pulse duration according to the translating informations. The changes in the first two properties are concerned optically with the analog modulation while the third one concern at most with digital modulation. All past methods are expensive with low efficiency and needs electrical or magnetic fields. In this technique the source of voice used

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Publication Date
Thu Dec 28 2023
Journal Name
مجلة الجامعة العراقية
The emergence of the Vietnamese National Movement in China 1921-1946
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The research, which was drawn from his doctoral thesis (People's Policy towards Vietnam 1949-1979), discussed the roots of the connections between the Chinese and Vietnamese communists since the 1920s, the presence of Ho Chi Minh and other Vietnamese communists in China, their influence by the revolutionary struggle of the Chinese Communist Party and their establishment of a group of The Vietnamese Revolutionary Societies and the Indo-Chinese Communist Party until the outbreak of the Vietnamese Revolution and their success in declaring the establishment of the Democratic Republic of Vietnam in 1946. Keywords: Ho Chi Minh, Chinese Communist Party, Indo-Chinese Communist Party, Democratic Republic of Vietnam, Chou En Lai.

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Publication Date
Fri Apr 01 2016
Journal Name
Astronomy Reports
Ionized gas in the circumgalactic vicinity of the M81 galaxy group
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Publication Date
Thu Dec 31 2015
Journal Name
Al-khwarizmi Engineering Journal
The Influence of Design and Technological Parameters on the MAF Process
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Abstract

 Experimental work from Magnetic Abrasive Finishing (MAF) tests was carried out design parameters (amplitude, and number of cycle which are formed the shape of electromagnetic pole), and technological parameters (current, cutting speed, working gap, and finishing time) all have an influence on the mechanical properties of the surface layer in MAF process. This research has made to study the effect of design and technological parameters on the surface roughness (Ra), micro hardness (Hv) and material removal (MR) in working zone. A set of experimental tests has been planned using response surface methodology according to Taguchi matrix (36) with three levels and six factors

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Publication Date
Tue Jun 01 2021
Journal Name
Political Sciences Journal
The Trust Factor of Oman’s Diplomacy in the US-Iranian Conflict
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من أجل فهم دور سلطنة عُمان في المفاوضات الإقليمية والوساطة وحل النزاعات يجب تقدير سياستها الخارجية، والتي سيتم تقييمها من أجل فهم كيفية نشأتها وتشكلها وأثر ذلك على مواقفها السياسية طوال سنوات حكم السلطان الراحل قابوس بن سعيد. وتقع عُمان في منطقة مضطربة، وقد طُلب منها في عدة مناسبات أن تعمل كمفاوض أو وسيط في الصراعات الإقليمية. سيبحث هذا البحث في كيفية قيام السلطنة بالوساطة الدولية، خاصة في الصراع الأمريكي

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Publication Date
Tue Feb 05 2019
Journal Name
Journal Of The College Of Education For Women
Study the positive effects of “Whatsup” application in the educational process
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Limited importance of research in a stand on the most important difficulties faced by both faculty and parents to communicate with each process to follow up on their children, and the analysis and inventory of the obstacles that hinder the educational process, and work to develop a vision of how to address these constraints and the important role of technology in the treatment of problems of the society so as to develop frameworks future to minimize the errors and the problems they face, and the development outlook for future generations in order to promote the educational level, especially that Iraq is going through a change in conditions in all sectors. Through the questionnaire, which includes questions set that was made on a sample o

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Publication Date
Tue Mar 30 2021
Journal Name
College Of Islamic Sciences
Problems distorting the divine books in the light of revealing interpretation
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Abstract

The research is presented according to an objective study on the ideological problems, especially the distortions that the divine scriptures have been subjected to under a false pretext that does not pertain to religion, namely that the heavenly books of the Torah and the Bible have been damaged or lost as a result of apostasy and persecution, and the writing of these books has been entrusted by people who have been bestowed Holiness, they have the testimony of the Church, so they distorted and omitted it in a manner suitable for securing their good and worldly gains, and the Holy Qur’an mentioned this explicitly, and they continued later, especially the Jews, in distorting the verses of the Holy Qur’an. This researc

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Publication Date
Sun Mar 01 2009
Journal Name
Journal Of Economics And Administrative Sciences
Use the method of parsing anomalous valueIn estimating the character parameter
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In this paper the method of singular value decomposition  is used to estimate the ridge parameter of ridge regression estimator which is an alternative to ordinary least squares estimator when the general linear regression model suffer from near multicollinearity.

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