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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 Jan 01 2018
Journal Name
Fme Transaction
The influence of frictional facing thickness on the contact pressure distribution of multi-disc dry clutches
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Frictional heat is generated when the clutch starts to engag. As a result of this operation the surface temperature is increased rapidly due to the difference in speed between the driving and driven parts. The influence of the thickness of frictional facing on the distribution of the contact pressure of the multi-disc clutches has been investigated using a numerical approach (the finite element method). The analysis of contact problem has been carried out for a multiple disc dry clutch (piston, clutch discs, separators and pressure plate). The results present the distribution of the contact pressure on all tShe surfaces of friction discs that existed in the friction clutch system. Axisymmetric finite element models have been developed to ac

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Publication Date
Fri Aug 10 2018
Journal Name
Ceramics International
Application of zirconia surface coating to improve fracture resistance and stress distribution of zirconia ceramic restorations
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Zirconia ceramic restoration (ZCR) has a higher fracture incidence rate than metal ceramic restoration. Different surface treatments were used to improve fracture performance of ZCR such as grit blasting (GB) by aluminium oxide powder. This type of surface treatment generate residual stresses on veneering ceramic causing crack initiation and ending with a fracture. In order to overcome the stress generated by GB, zirconia surface coating is used as a surface treatment to improve fracture resistance and to accommodate stresses along the ZCR layers. Fifty zirconia ceramic crowns were fabricated and divided according to the type of surface treatment into three groups; the first group is (ZG), involving 20 cores were coated with a mixture of pa

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Publication Date
Sun Dec 07 2014
Journal Name
Baghdad Science Journal
Calculation of Radial Density Distribution Function for main orbital of Carbon atom and Carbon like ions
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Radial density distribution function of one particle D(r1) was calculated for main orbital of carbon atom and carbon like ions (N+ and B- ) by using the Partitioning technique .The results presented for K and L shells for the Carbon atom and negative ion of Boron and positive ion for nitrogen ion . We observed that as atomic number increases the probability of existence of electrons near the nucleus increases and the maximum of the location r1 decreases. In this research the Hartree-fock wavefunctions have been computed using Mathcad computer software .

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Publication Date
Mon Jan 01 2018
Journal Name
Fme Transaction
The influence of frictional facing thickness on the contact pressure distribution of multi-disc dry clutches
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Publication Date
Fri Feb 08 2019
Journal Name
Iraqi Journal Of Laser
Random Number Generation for Quantum Key Distribution Systems Based on Shot-Noise Fluctuations in a P-I-N Photodiode
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A simple setup of random number generator is proposed. The random number generation is based on the shot-noise fluctuations in a p-i-n photodiode. These fluctuations that are defined as shot noise are based on a stationary random process whose statistical properties reflect Poisson statistics associated with photon streams. It has its origin in the quantum nature of light and it is related to vacuum fluctuations. Two photodiodes were used and their shot noise fluctuations were subtracted. The difference was applied to a comparator to obtain the random sequence.

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Publication Date
Sun Mar 07 2010
Journal Name
Baghdad Science Journal
Effect of magnetic water in the some parameters of growth & activity of some enzymes in the ( Raphanus raphanistrum L.) Plant
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Publication Date
Mon Sep 30 2024
Journal Name
Medical Journal Of Babylon
Effectiveness of Deep Breathing Technique on Pain Level of School Children during Catheterization
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Publication Date
Sun Jun 21 2020
Journal Name
Iraqi Journal Of Pharmaceutical Sciences ( P-issn 1683 - 3597 E-issn 2521 - 3512)
Enhancement of Aqueous Solubility and Dissolution Rate of Etoricoxib by Solid Dispersion Technique
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Etoricoxib (EXB) is a highly selective cox-2 inhibitor which belongs to the non-steroidal anti-inflammatory drug (NSAID). EXB is a class II drug according to the biopharmaceutical classification system (BCS), which possess a very low aqueous solubility in water.  In the present study, many trials were made to improve the aqueous solubility and dissolution rate of EXB by solid dispersion technique.

Eighteenth EXB formulas were formulated as a solid dispersion using a variety of hydrophilic polymers (as carriers)   including poloxamer 407 (PXM 407), poloxamer 188 (PXM 188) and polyethylene glycol 4000 (PEG 4000) at different drug: polymer ratios (1:1, 1:3 and 1:5). These formulas were prepared by two methods; solvent

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Publication Date
Sun Jan 01 2023
Journal Name
Journal Of Molecular Liquids
Theoretical modeling study on preparation of nanosized drugs using supercritical-based processing: Determination of solubility of Chlorothiazide in supercritical carbon dioxide
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Publication Date
Wed Nov 27 2024
Journal Name
Frontiers In Education
The impact of using artificial intelligence techniques in improving the quality of educational services/case study at the University of Baghdad
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The utilization of artificial intelligence techniques has garnered significant interest in recent research due to their pivotal role in enhancing the quality of educational offerings. This study investigated the impact of employing artificial intelligence techniques on improving the quality of educational services, as perceived by students enrolled in the College of Pharmacy at the University of Baghdad. The study sample comprised 379 male and female students. A descriptive-analytical approach was used, with a questionnaire as the primary tool for data collection. The findings indicated that the application of artificial intelligence methods was highly effective, and the educational services provided to students were of exceptional quality.

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