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Experimental Study of Optimum Chilled Water Distribution Configuration in Air Conditioning Terminal Unit Using RSM Technique
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The distribution of chilled water flow rate in terminal unit is an important factor used to evaluate the performance of central air conditioning unit. A prototype of A/C unit has been made, which contains three terminal units with a complete set of accessories (3-way valve, 2-way valve, and sensors) to study the effect of the main parameters, such as total water flow rate and chilled water supply temperature with variable valve opening. In this work, 40 tests were carried out. These tests were in two groups, 20 test for 3-way valve case and 20 test for 2-way valve case. These tests were performed at three levels of valve opening, total water flow rate and water supply temperature according to the design matrices established by Design of Experiment (DOE) software 'version 7' with Response surface methodology (RSM) technique. The model was conducted for each case of total heat rate, then checked statistically for adequacy by Analysis of variance (ANOVA), and found good with 95% confidence level. The results showed that the water supply temperature has a significant effect on the total heat rate of two cases. It was found that the optimum solution for maximum total heat rate and minimum flow deviation represented by standard deviation was obtained at 10°C water supply temperature, 5.5 l/min total water flow rate and 70% valve opening. The total heat rate and standard deviation were (890.249 Watt), (0.000513), respectively in three-way valve case and (743.155 Watt), (0.00277), respectively in two-way valve case. Finally, the predicted and experimental results of total heat rate and standard deviation were in agreement with a maximum error of 6.6 % in three-way valve case and 1.4% in two-way valve case.

 

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Publication Date
Thu Jan 01 2015
Journal Name
Agriculture And Agricultural Science Procedia
Practical Deviation in Sustainable Pesticide Application Process
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Publication Date
Thu Sep 02 2021
Journal Name
Journal Of Al-frahedis Arts
Public Relations Activities in Iraqi Industrial Companies
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Due to the impact of industrial companies on the ransformations and developments witnessed by the world in general nd Iraq in particular, especially in the industrial and economic Jonrnal spects, the liberalization of internal and external trade, and the idoption of the open market policy in Iraq, which led to the intensification of competition between industrial companies and heir products and services, and the increase and diversity of the Onumber of alternatives Available to the public on the one hand, and he diversity and change of their desires and needs on the other hand, which was reflected in the reality of those companies and heir products or services, especially in light of the great challenges facing companies and the deteriorat

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Publication Date
Wed Apr 01 2009
Journal Name
2009 Ieee Wireless Communications And Networking Conference
Power Efficiency Maximization in Cognitive Radio Networks
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Cognitive radio technology is used to improve spectrum efficiency by having the cognitive radios act as secondary users to access primary frequency bands when they are not currently being used. In general conditions, cognitive secondary users are mobile nodes powered by battery and consuming power is one of the most important problem that facing cognitive networks; therefore, the power consumption is considered as a main constraint. In this paper, we study the performance of cognitive radio networks considering the sensing parameters as well as power constraint. The power constraint is integrated into the objective function named power efficiency which is a combination of the main system parameters of the cognitive network. We prove the exi

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Publication Date
Sat Jan 01 2011
Journal Name
Journal Of Computer Sciences
Connectedness in Graphs and Gm-Closure Spaces
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This paper is devoted to the discussion the relationships of connectedness between some types of graphs (resp. digraph) and Gm-closure spaces by using graph closure operators.

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Publication Date
Sun Aug 05 2018
Journal Name
Al Ustath
Healing Powers in Gloria Naylor's Mama Day
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This paper examines Gloria Naylor's Mama Day (1988) that shows the mixing of African and American culture. Afro-American authors reject the Eurocentric hypothesis that slavery had ended the Afro-American cultural engagement in Africa. African Americans represent an essential fabric of American society, sharing many traditions, habits, and traits with the American society. Yet, at the same time, Naylor portrays Afro-American individuals in Mama Day as a separate unit with a unique and rich culture. These mannerisms expose a kind of resistance, appreciation to her African identity, history, and roots. A tale of a conjure woman located in Willow Springs' mythical isle, Mama Day, highlights the mystical, storytelling, and folkloristic customs.

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Publication Date
Tue Sep 19 2017
Journal Name
Al-academy
semantic expressive makeup in the film Orwellian
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    Enjoy cinema privileged position , they have the ability to influence and the impact of including environs of prior art , and what distinguishes them , possessing motion picture , especially since the film possesses through its means technical ( camera , lighting, sound, editing , costume, scenery and makeup ) that work together in harmony and harmony to create enchanting fantasy world does not exist only in the imagination of corrupt officials . Out of imagination found that the art of make-up one of the means that enable it to create characters imagined located between simulate realistic characters (such manifestations of blood , cut leg, wounds , burns , etc. ..) and the figures are unrealistic , particularly in the

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Publication Date
Sun Oct 15 2023
Journal Name
Bionatura
Nanohydroxyapatite in enamel remineralization and tooth hypersensitivity
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This study evaluates the advantages of employing nano-hydroxyapatite in dentistry, particularly for preventive treatment applications. Only electronically published papers were searched within this review. Sources: "PubMed" website was the only source used to search for data. 92 most relevant papers to the topic were selected, especially the original articles and review papers, from 1990 till the 1st of April 2022. The morphology of nano-hydroxyapatite, as well as the structure of its crystals, are close to that of dental enamel. As a result, hydroxyapatite can biomimetically replace the natural enamel mineral element. Keywords: remineralization of enamel, nanotechnology, nanohydroxyapatite, hypersensitivity.

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Publication Date
Tue Mar 01 2016
Journal Name
Al-academy
Metaphor in product design: قيس والي عباس
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Addresses current research to the subject of metaphor as a field important in the design of industrial product, so it was a problem search: Does industrial product which is designed mainly to reflect the principle of metaphor role in receiving, and how the application of mechanisms theory correct as stipulated in institutions metaphor properly for this orientation in achieving those metaphors. What are the relations of reciprocity that influenced the establishment of the design and construction of the system for industrial product, the objectives of the research were standing on the interactive nature of the relations between the metaphor and the process of industrial product design? And identify strengths and weaknesses in the processes

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Publication Date
Tue Feb 12 2019
Journal Name
Iraqi Journal Of Physics
Linear attenuation coefficient measurement in polymer composite
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Linear attenuation coefficient of polymer composite for beta particles and bremsstrahlung ray were investigated as a function of the absorber thickness and energy. The attenuation coefficient were obtained using NaI(Tl) energy selective scintillation counter with 90Sr/90Y beta source having an energy range from 0.1-1.1 MeV. The present results show the capability of this composite to absorber beta particles and bremsstrahlung ray that yield from it. That’s mean it is useful to choice this composite for radiation shielding of beta ray with low thickness.

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Publication Date
Thu Jun 30 2022
Journal Name
نسق
"Flow Theory and Its Role in Education
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