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Assessment of using different ozone-friendly R22 alternative refrigerants in residential air conditioners in a high-ambient temperature country
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Abstract<p>The performance of a vapor compression refrigeration system (VCRS)-based residential air conditioner operating in a high-ambient temperature (HAT) country was investigated using six zero-ODP (ozone depletion potential) refrigerants as replacements to R22. The non-flammable alternative refrigerants considered in the present research were R134a, R404A, R407C, R410A, R448A, and R507A. Using the basic conservation laws, the VCRS was modeled during steady-state operation and solved using engineering equation solver (EES) software. Coefficient of performance (COP), pressures and temperatures at compressor suction and discharge, Global Warming Potential (GWP), critical pressure and temperature, compressor pressure ratio, volumetric cooling capacity (VCC) specific cooling capacity (SCC), and refrigeration effect were utilized as assessment criteria for the alternative refrigerants considered. From these refrigerants, the highest values of suction pressure, discharge temperature, and condenser pressure were attained by R410A. In addition, the discharge temperatures for all refrigerants, except R134a, were all higher than their corresponding critical values, causing a quicker drop in the VCRS’s performance. As an alternative refrigerant, R407C showed the highest SCC of 141.0 kJ/kg followed directly by 139.2 and 138.0 kJ/kg for R410A and R448A, respectively. A reverse trend was found for VCC with respective values of 4722 and 3775 kJ/m<sup>3</sup> for R410A and R448A. Lower volume flow rates and smaller-sized compressors are expected for higher VCC refrigerants. The same trend was found for the compressor’s specific work input and condenser’s specific heat transfer with values of (51.14, 46.82, and 45.38 kJ/kg) and (190.3, 187.8, and 183.4 kJ/kg) for R410A, R407C, and R448A, respectively. For applications in HAT countries, larger condenser’s specific heat transfer makes the refrigerant more applicable. Conversely, with respect to COP, refrigerant R134a with a value of 3.075 was the superior alternative followed by R448A and R407C with respective COPs of 3.042 and 3.011. Based on the overall assessment in terms of environmental obligation, COP, compressor input power, refrigerant flow rate required, and all the evaluations made in this research, refrigerant R448A was recommended as the most appropriate substitute to R22 which can effectively be used in residential air conditioners in a HAT country.</p>
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Publication Date
Sun Oct 18 2026
Journal Name
Journal Of Baghdad College Of Dentistry
Craniometric asymmetry assessment in class I and class II skeletal relationship patients using helical computed tomography sample aged between 18-35 years
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Background: Asymmetry assessment is an important component of orthodontic diagnosis and treatment planning. Several studies attempted to find the relationship between craniometric asymmetry and skeletal jaws relationship and many authors found some extent of asymmetry in individuals with normal jaws relationship. The use of Computed tomography (CT) allows for the assessment of asymmetry on a dimensionally accurate volumetric image, aim of the study is to determine if there are differences in craniometric asymmetry between patient with skeletal class I and patients with skeletal class II relationship using Helical CT scan. Materials and Methods: Ninety individuals with clinically symmetrical faces were imaged with Helical CT scan, and aging

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Publication Date
Tue Jan 17 2017
Journal Name
International Journal Of Computer Applications
Improving of Photovoltaic Cell Performance by Cooling using Two different Types of Fins
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Publication Date
Fri Dec 01 2023
Journal Name
Baghdad Science Journal
Simultaneous Determination of Binary Mixture of Estradiol and Progesterone Using Different Spectrophotometric Methods
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Four rapid, accurate and very simple derivative spectrophotometric techniques were developed for the quantitative determination of binary mixtures of estradiol (E2) and progesterone (PRG) formulated as a capsule. Method I is the first derivative zero-crossing technique, derivative amplitudes were detected at the zero-crossing wavelength of 239.27 and 292.51 nm for the quantification of estradiol and 249.19 nm for Progesterone. Method II is ratio subtraction, progesterone was determined at λmax 240 nm after subtraction of interference exerted by estradiol. Method III is modified amplitude subtraction, which was established using derivative spectroscopy and mathematical manipulations. Method IIII is the absorbance ratio technique, absorba

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Publication Date
Mon Oct 02 2023
Journal Name
Journal Of Engineering
Control of Propagation of Salt Wedge by using Roughness Blocks having Different Inclination
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The hydraulic conditions of a flow previously proved to be changed when placing large-scale geometric roughness elements on the bed of an open channel. These elements impose more resistance to the flow.  The geometry of the roughness elements, the numbers used, and the configuration are parameters that can affect the hydraulic flow characteristics. The target is to use inclined block elements to control the salt wedge propagation pointed in most estuaries to prevent its negative effects. The Computational Fluid Dynamics CFD Software was used to simulate the two-phase flow in an estuary model. In this model, the used block elements are 2 cm by 3 cm cross-sections with an inclined face in the flow direction, with a length

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Publication Date
Mon Mar 01 2021
Journal Name
Al-khwarizmi Engineering Journal
Building a High Accuracy Transfer Learning-Based Quality Inspection System at Low Costs
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      Products’ quality inspection is an important stage in every production route, in which the quality of the produced goods is estimated and compared with the desired specifications. With traditional inspection, the process rely on manual methods that generates various costs and large time consumption. On the contrary, today’s inspection systems that use modern techniques like computer vision, are more accurate and efficient. However, the amount of work needed to build a computer vision system based on classic techniques is relatively large, due to the issue of manually selecting and extracting features from digital images, which also produces labor costs for the system engineers.       In this research, we pr

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Publication Date
Mon Mar 01 2021
Journal Name
Al-khwarizmi Engineering Journal
Building a High Accuracy Transfer Learning-Based Quality Inspection System at Low Costs
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      Products’ quality inspection is an important stage in every production route, in which the quality of the produced goods is estimated and compared with the desired specifications. With traditional inspection, the process rely on manual methods that generates various costs and large time consumption. On the contrary, today’s inspection systems that use modern techniques like computer vision, are more accurate and efficient. However, the amount of work needed to build a computer vision system based on classic techniques is relatively large, due to the issue of manually selecting and extracting features from digital images, which also produces labor costs for the system engineers.

  &nbsp

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Publication Date
Tue Oct 01 2019
Journal Name
Journal Of Economics And Administrative Sciences
Comparison of some robust methods in the presence of problems of multicollinearity and high leverage points
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Abstract

The multiple linear regression model of the important regression models used in the analysis for different fields of science Such as business, economics, medicine and social sciences high in data has undesirable effects on analysis results . The multicollinearity is a major problem in multiple linear regression. In its simplest state, it leads to the departure of the model parameter that is capable of its scientific properties, Also there is an important problem in regression analysis is the presence of high leverage points in the data have undesirable effects on the results of the analysis , In this research , we present some of

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Publication Date
Sun Oct 18 2026
Journal Name
Journal Of Physical Education
Strength Variable Analysis With the Height of Body Mass Center In High Spike Position 4 In Volleyball League Players
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Publication Date
Wed Nov 13 2019
Journal Name
Al-kindy College Medical Journal
Disturbances of Amino Acid Metabolism in Neurologic Disorders detected by fluorescent high performance liquid chromotograghy (HPLC) in Baghdad - IRAQ
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Background:Amino acid disorders are a major group of inborn error metabolism (IEM) with variable clinical presentation; its diagnosis constitutes a real challenge in a community with high consanguinity rate and no systematic newborn screening.

Objectives: to provide data about amino acid disorders detected in high-risk Iraqi children by using quantitative amino acid fluorescent high performance liquid chromatography (HPLC) analysis.

Type of the study: Cross-sectional study.

Methods: a descriptive cross sectional study from 1st February to 1st December 2014, at Neurological ward and clinic of the Children Welfare teaching Hospital, in Baghdad - Ira

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Publication Date
Sat Aug 01 2015
Journal Name
Journal Of Economics And Administrative Sciences
Requirements high commitment management to achieve entrepreneurship strategic in busness organization / Field research in Iraqi construction companies
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This research came to shed light on the relationship between the requirements of (practices) high commitment management (participative decision making،information sharing، training and development،team working،rewards،selective staffing،job security ) and strategic entrepreneurship dimensions (entrepreneurial culture،entrepreneurial leadership،entrepreneurial mindset، strategic management resources ) Sought to achieve the number of goals the knowledge and applied, and tested the relationship and impact between variables in a sample size of 100 directors of personnel departments and divisions and their associates in the Iraqi contractors in Baghdad (Hamorabi، Mutassim، AL Rasheed، AL Mansour  )، focused research

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