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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
Tue Sep 03 2024
Journal Name
African Journal Of Biomedical Research
Assessment of Solubility, Moisture Content, Water Absorption and Thickness of Bioplastic synthesized from Iraqi Amber Rice Husks
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Publication Date
Wed Jul 01 2015
Journal Name
Journal Of Engineering
Evaluation of Alum/Lime Coagulant for the Removal of Turbidity from Al- Ahdab Iraqi Oilfields Produced Water
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The removal of turbidity from produced water by chemical coagulation/flocculation method using locally available coagulants was investigated. Aluminum sulfate (alum) is selected as a primary coagulant, while calcium hydroxide (lime) is used as a coagulant aid. The performance of these coagulants was studied through jar test by comparing turbidity removal at different coagulant/ coagulants aid ratio, coagulant dose, water pH, and sedimentation time. In addition, an attempt has been made to examine the relationship between turbidity (NTU) and total suspended solids (mg/L) on the same samples of produced water. The best conditions for turbidity removal can be obtained at 75% alum+25% lime coagulant at coagulant dose of 80 m

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Publication Date
Sun Jan 01 2023
Journal Name
Journal Of Engineering
The Effects of Different Water Types on the Dissolution, Physical Appearance, and Compressive Strength of Gypsum Rock
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Dissolution of gypsum rock in water is significant, which may result in hydrocarbon reservoir formation and evaporate deposits. However, the complexity of the gypsum dissolution process is still of interest because of its uncleanness that requires more critical analysis. The objectives of this experimental study are emphasis on the dissolution characteristics of gypsum rock under room temperature and by various types of water; namely: deionized, tap, fresh, acidic, well, and normal rainwatre. In addition, the influences of dissolution on gypsum rock's mechanical and physical characteristics. Gypsum rock was obtained from Agjalar area, in the southwest of Sulaymaniyah city, Northern Iraq. Experimental results show that we

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Publication Date
Wed Jan 01 2020
Journal Name
Biochemical And Cellular Archives
EVALUATION OF WATER STRESS EFFECT ON SOME CHEMICAL PROPERTIES OF SEVERAL SUNFLOWER VARIETIES CALLUS TREATED WITH ULTRAVIOLET
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The study was carried out in plant tissue culture laboratory, University of Baghdad during the period 2017-2019, as factorial experiment in complete randomized design, to study the effect of PEG at (0, 2, 4, 6 and 8%) on physiological and chemical changes in callus of three sunflower (Ishaqi 1, Aqmar and Al-haga) induced by the cultivation of the young stem in vitro under water stress. The content of callus cells of SOD, POD, CAT and APX enzymes as well as content of hydrogen peroxide were determined as indicators to determine the effect of PEG in callus tissue cells cultivated on medium equipped with the PEG concentrations. The results showed that cultivars were differs significantly and Al-hajavariety was superior in increasing SOD to 24.

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Publication Date
Wed Oct 02 2024
Journal Name
International Development Planning Review
A COMPARATIVE STUDY OF THE AMOUNT OF FORCE EXERTED ON THE GROUND AND THE TIME OF PROPULSION IN THE VERTICAL AND HORIZONTAL JUMPING TESTS FROM STABILITY USING A FOOT SCAN DEVICE
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Publication Date
Fri Feb 20 2026
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
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 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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