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Investigation of R134a Flow Boiling Heat Transfer and Pressure Drop in the Evaporator Test Section of Refrigeration System
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This paper presents an experimental and theoretical analysis to investigate the two-phase flow boiling heat transfer coefficient and pressure drop of the refrigerant R-134a in the evaporator test section of the refrigeration system under different operating conditions. The test conditions considered are, for heat flux (13.7-36.6) kW/m2, mass flux (52-105) kg/m2.s, vapor quality (0.2-1) and saturation temperature (-15 to -3.7) ˚C. Experiments were carried out using a test rig for a 310W capacity refrigeration system, which is designed and constructed in the current work. Investigating of the experimental results has revealed that, the enhancement in local heat transfer coefficient for relatively higher heat flux 36.6 kW/m2 was about 38% compared to 13.7 kW/m2 at constant operating conditions. The enhancement in heat transfer coefficient was about 57% when the mass flux increased from 52 kg/m2.s to 105 kg/m2.s at constant test conditions. The enhancement in the heat transfer coefficient was about 64% when the saturation temperature increased from -8 to -3.7 at fixed refrigerant mass velocity and heat flux. The effect of mass velocity on pressure drop was relatively higher by about 27% than that for heat flux at specified test conditions. The comparison between the experimental and theoretical results has shown an acceptable agreement with an average deviation of 21%.

 

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Publication Date
Tue Jun 01 2021
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
A New Approach of Morgan-Voyce Polynomial to Solve Three Point Boundary Value Problems
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In this paper, a new procedure is introduced to estimate the solution for the three-point boundary value problem which is instituted on the use of Morgan-Voyce polynomial. In the beginning, Morgan-Voyce polynomial along with their important properties is introduced. Next, this polynomial with aid of the collocation method utilized to modify the differential equation with boundary conditions to the algebraic system. Finally, the examples approve the validity and accuracy of the proposed method.

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Publication Date
Sat Sep 30 2023
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Desulphurization of Simulated Oil Using SAPO-11 with CNT's as Adsorbent: A Kinetic Study
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In this study, sulfur was removed from imitation oil using oxidative desulfurization process. Silicoaluminophosphate (SAPO-11) was prepared using the hydrothermal method with a concentration of carbon nanotubes (CNT) of 0% and 7.5% at 190 °C crystallization temperature. The final molar composition of the as-prepared SAPO-11 was Al2O3: 0.93P2O5: 0.414SiO2. 4% MO/SAPO-11 was prepared using impregnation methods. The produced SAPO-11 was described using X-ray diffraction (XRD) and Brunauer-Emmet-Teller (N2 adsorption–desorption isotherms). It was found that the addition of CNT increased the crystallinity of SAPO-11. The results showed that the surface area of SAPO-11 cont

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Publication Date
Sun Mar 30 2003
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Improvement of CIATIM-201 Grease Properties for Use under Severe Conditions using Suitable Additives
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Publication Date
Wed Oct 20 2021
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Zenali Iteration Method For Approximating Fixed Point of A δZA - Quasi Contractive mappings
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This article will introduce a new iteration method called the zenali iteration method for the approximation of fixed points. We show that our iteration process is faster than the current leading iterations  like Mann, Ishikawa, oor, D- iterations, and *-  iteration for new contraction mappings called  quasi contraction mappings. And we  proved that all these iterations (Mann, Ishikawa, oor, D- iterations and *-  iteration) equivalent to approximate fixed points of  quasi contraction. We support our analytic proof by a numerical example, data dependence result for contraction mappings type  by employing zenali iteration also discussed.

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Publication Date
Tue Oct 02 2018
Journal Name
Iraqi Journal Of Physics
Study photometric properties of spiral galaxy NGC 4448 using CCD camera with multiband filters
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The goal of our study is to perform detailed multiband surface photometry of the spiral galaxy NGC 4448 and its brightest star-forming regions. The structure and composition of the stellar population in the surface brightness galaxy NGC 4448 was studied using BVR CCD photometry. The observations were obtained on the 1.88 m optical telescope of Kottamia Astronomical Observatory (KAO), Egypt. A two-dimensional decomposition of the galaxy bulge and disk components is carried out. A powerful star forming region is observed near the galactic center. Based on the positions of the various components of the galaxy in two color diagrams. From the observations, the surface brightness profiles, Ellipticity profiles, position angle profiles and colo

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Publication Date
Fri Jun 30 2023
Journal Name
Iraqi National Journal Of Nursing Specialties
Assessment of Nurses' Knowledge About Chest Physiotherapy Techniques for Patients With Corona Virus Disease
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Abstract

Objective(s): A descriptive study aimed to determine nurses' knowledge about chest physiotherapy techniques for patients with Corona virus disease and observe the relationship between nurses' knowledge and their socio-demographic characteristics.

Methodology: The study was directed in isolation units of Al- Hussein teaching hospitals in Thi-Qar, Iraq for the period from June 1st,  2022 to November 27th, 2022. Non- probability (purposively) sample comprised 41 nurses. A questionnaire was used for data collection and it consists of two parts: the first part comprises socio demographic features, the second part includes self- administered questionnaire sheet wa

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Publication Date
Sun Jan 01 2017
Journal Name
Catalysis Science & Technology
Mechanisms governing selective hydrogenation of acetylene over γ-Mo<sub>2</sub>N surfaces
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We demonstrate that the selective hydrogenation of acetylene depends on energy profile of the partial and full hydrogenation routes and the thermodynamic stability of adsorbed C2H2 in comparison to C2H4.

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Publication Date
Fri Jan 01 2016
Journal Name
Statistics And Its Interface
Search for risk haplotype segments with GWAS data by use of finite mixture models
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The region-based association analysis has been proposed to capture the collective behavior of sets of variants by testing the association of each set instead of individual variants with the disease. Such an analysis typically involves a list of unphased multiple-locus genotypes with potentially sparse frequencies in cases and controls. To tackle the problem of the sparse distribution, a two-stage approach was proposed in literature: In the first stage, haplotypes are computationally inferred from genotypes, followed by a haplotype coclassification. In the second stage, the association analysis is performed on the inferred haplotype groups. If a haplotype is unevenly distributed between the case and control samples, this haplotype is labeled

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Publication Date
Mon Oct 22 2018
Journal Name
Journal Of Economics And Administrative Sciences
Using Mehar method to change fuzzy cost of fuzzy linear model with practical application
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  Many production companies suffers from big losses because of  high production cost and low profits for several reasons, including raw materials high prices and no taxes impose on imported goods also consumer protection law deactivation and national product and customs law, so most of consumers buy imported goods because it is characterized by modern specifications and low prices.

  The production company also suffers from uncertainty in the cost, volume of production, sales, and availability of raw materials and workers number because they vary according to the seasons of the year.

  I had adopted in this research fuzzy linear program model with fuzzy figures

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Publication Date
Sat Jan 01 2011
Journal Name
Iraqi Journal Of Physics
Characteristics of Zinc Oxide Film Prepared by Chemical Spray Deposition as a Gas Sensor
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Zinc oxide thin films were deposited by chemical spray pyrolysis onto glass substrates which are held at a temperature of 673 K. Some structural, electrical, optical and gas sensing properties of films were studied. The resistance of ZnO thin film exhibits a change of magnitude as the ambient gas is cycled from air to oxygen and nitrogen dioxide

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