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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
Mon Feb 04 2019
Journal Name
Journal Of The College Of Education For Women
BUMPINESS IN THE ATMOSPHERE IN IRAQ STUDY IN THE GEOGRAPHY OF CLIMATE
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Bumpiness in the atmosphere is the vertical movement of air, whether
upward or downward movement and the bumpiness is accompanied by areas
of unrest in the air and wind. And contribute to each of the coups thermal
fronts, wind, wind and thunderstorms. Moreover, bumpiness is net of the
reasons that lead to circumstances is appropriate to cut the wind, and this
contributes to the formation of bumpiness in the atmosphere. The study found
that the noon of the times, which is expected to occur where clear-air
bumpiness during flights because of the warmth of the earth's surface. The
study found increased incidence of air hole during the summer, especially
July, due to increased incidence of coup surface, while the s

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Publication Date
Thu Dec 04 2025
Journal Name
Iraqi Journal Of Applied Physics
Effect of Gas Mixing Ratio on Energy Band Gap of Mixed-Phase Titanium Dioxide Nanostructures Prepared by Reactive Magnetron Sputtering Technique
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Publication Date
Wed Dec 29 2021
Journal Name
Journal Of The College Of Education For Women
The Impact of the Seven Principles of Good Practice as a Teaching Technique on EFL Student –Teachers' Performance: سوسن سعود عزيز
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The interest in pre-service teacher training has become influential in teaching English as a foreign language, and the purpose of this training course is to prepare qualified teachers to teach effectively through the application of this technique by undergraduate students. This research aims to find out the effect of using the seven principles of good practice as a teaching technique on the fourth stage student-teachers’ performance at the College of Education for Women/University of Baghdad, during the academic year 2017-2018. The sample includes (60) students selected according to the stratified sampling method. The observational checklist used by the department to assess the student teachers’ performance during the practicum perio

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Publication Date
Tue Oct 25 2022
Journal Name
Aip Conference Proceedings
Consequence of violet laser irradiation on the optical properties of mawsoniteCu6Fe2SnS8 [CFTS] thin films deposited via semi-computerized spray pyrolysis technique
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Publication Date
Wed Aug 10 2022
Journal Name
Ibero-american Journal Of Exercise And Sports Psychology
The impact of applying the K-W-L self-scheduling technique on first-year intermediate students' learning of basic volleyball skills
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The impact of applying the K-W-L self-scheduling technique on first-year intermediate students' learning of basic volleyball skills, Ayad Ali Hussein*, Israa Fouad Salih

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Publication Date
Fri Sep 09 2022
Journal Name
Journal Of Ovonic Research
The effects of CuO doping on structural, electrical and optical properties of CdO thin films deposited by pulsed laser deposition technique
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Thin films of (CdO)x (CuO)1-x (where x = 0.0, 0.2, 0.3, 0.4 and 0.5) were prepared by the pulsed laser deposition. The CuO addition caused an increase in diffraction peaks intensity at (111) and a decrease in diffraction peaks intensity at (200). As CuO content increases, the band gap increases to a maximum of 3.51 eV, maximum resistivity of 8.251x 104 Ω.cm with mobility of 199.5 cm2 / V.s, when x= 0.5. The results show that the conductivity is ntype when x value was changed in the range (0 to 0.4) but further addition of CuO converted the samples to p-type.

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Publication Date
Tue Jan 01 2019
Journal Name
Journal Of Global Pharma Technology
Phenotypic, genotypic correlation and path coefficient for several traits of maize under watered and water stress
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Scopus
Publication Date
Thu Dec 01 2011
Journal Name
Iraqi Journal Of Physics
Influence of water absorption on fatigue behavior for chopped and woven-glass-fibers-reinforced PMMA denture
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The influence of fiber orientation and water absorption on fatigue crack growth resistance for cold cure acrylic (PMMA) reinforced by chopped and woven -glass-fibers were investigated. A weight of 2 g for chopped fibers and the same weight for woven -glass-fibers (one layer) were used to prepare samples. Some of these samples would storage in dry condition; the others were immersed in water for 15 days. Fatigue test was carried out. The results shows that, for PMMA, the initial bending stress for dry specimen was 3.392 N/cm2 and the number of cycles were 1364, the initial bending stress for wet samples was 4.20 N/cm2, and the number of cycles was 2411. The samples would cut in two pieces because of the cracks would propagated fast during

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Publication Date
Tue Jan 08 2019
Journal Name
Iraqi Journal Of Physics
Effect of plasma jet on the water and hydrogen peroxide that used for assisted teeth bleaching
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In this work the interaction of plasma jet with water and hydrogen peroxide liquids used for assisted teeth bleaching by plasma jet had been study. A homemade plasma jet system was used. The plasma jet supply by 15 W electrical power generated by high voltage power supply of 9.6 kV peak to peak and frequency of 33 kHz .this power supply generate high electric field on electrodes that would be enough to ionize the argon gas. Some important agents were study such as the effect of the Ar gas flow rates on the length of the plasma jet, the influence of plasma jet on some properties of water and two hydrogen peroxide concentrations 25 % and 30 % like pH, conductivity and liquid temperature for different exposure time. The liquids temperature

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Publication Date
Fri Dec 01 2023
Journal Name
Iop Conference Series: Earth And Environmental Science
Improving the Growth and Production of Beets by Fertilizing with Fish Water and Spraying Lentil Extract
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Abstract<p>The experiment was conducted in the fields belonging to the Department of Horticulture, College of Agricultural Engineering Sciences, University of Baghdad, at Al-Jadriya Complex / Station A, for the autumn season of 2022-2023. The aim was to study the effect of water fish irrigation and water lens plant extract foliar application on the growth and productivity of beetroot. The experiment included two factors: the first factor was water fish irrigation with five concentrations (A) Control treatment (irrigation with river water and recommended fertilization), (B) Water fish irrigation at 25% concentration, (C) water Fish irrigation at 50% concentration, (D) Water Fish irrigation at 75%</p> ... Show More
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