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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
Mon Feb 23 2026
Journal Name
Journal Of Baghdad College Of Dentistry
An Evaluation the Effect of Alcohol Presence in Mouth Washes on Force Degradation of Different Configurations of Elastomeric Chains
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Background: Elastomeric chains are one of the most commonly used force delivery systems. They have the ability to exert a continuous force, convenience of use, compatibility to oral environment and cost effectiveness but one of the inherited disadvantages is force degradation. Materials and methods: This in vitro study was designed to evaluate the effect of alcohol presence in mouthwashes on force decay of different configurations of clear elastomeric chains from (Ortho Technology company) which are: closed , short and long under the effect of time at (Initial, 1, 2, 3 and 4 weeks) intervals with exposure to different chemical solutions. A total (540) modules of elastomeric chains of three different types (long, short and closed) trans

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Publication Date
Tue Dec 11 2018
Journal Name
Iraqi National Journal Of Nursing Specialties
Impact of Different Degrees of Uterine Prolapse on Sexual Function of Women at Teaching Hospitals in Al-Hilla City
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Background: Women sexuality is basic right and it plays a major role in women's Health aspects. Up is one of the factors that lead to sexual dysfunction while the incidence of it is rising as UP severity being more. Objectives: To assess the impact of different degrees of uterine prolapse on sexual function of women at teaching hospitals in AL-Hilla City. Methodology: A descriptive analytical study was conducted from 1ST Feb to 10th Jun /2014 to assess the impact of different degrees of uterine prolapse on sexual function for women who attend to consultant clinic at teaching hospitals in AL-Hilla City

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Publication Date
Mon Mar 01 2010
Journal Name
Journal Of Economics And Administrative Sciences
The economic feasibility of substituting different residues replaces part of the barley In the fattening of the Arabian lambs
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This experiment was carried out at the Grdarash field belongs to the Agricultural researches directorate/general Agriculture directorate-Erbil in September (2007)، 27 Arabic lambs aged (5-6 months) With average initial weight (39.178 Kg/lamb) were used. Lambs were divided in to (3) groups (9 lambs/group). Control group was fed on (85% barely، 10% bran and 5% straw)، and second and third groups were fed on various by-product in replacement with barely in loss and block shape respectively.

The total gain of three groups were (392708.32، 634826.52 & 445613.72 ID resp

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Publication Date
Mon Jan 01 2024
Journal Name
Brazilian Dental Science
Evaluation of flexural strength and degree of conversion of temporary crown materials at different aging periods in artificial saliva
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Objective: Evaluate the effects of different storage periods on flexural strength (FS) and degree of conversion (DC) of Bis-Acryl composite and Urethane dimethacrylate provisional restorative materials. Material and Methods: A total of 60 specimens were prepared from four temporary crown materials commercially available and assigned to four tested groups (n = 15 for each group): Prevision Temp, B&E CROWN, Primma Art, and Charm Temp groups. The specimens were stored in artificial saliva, and the FS was tested after 24 h, 7 d, and 14 d. A standard three-point bending test was conducted using a universal testing machine. Additionally, the DC was determined using a Fourier transform infrared spectroscopy (FTIR) device. The data were analyzed st

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Publication Date
Mon May 01 2023
Journal Name
Journal Of Engineering
Experimental Investigation of Heat Transfer Enhancement in a Double Pipe Heat Exchanger Using Compound Technique of Transverse Vibration and Inclination Angle
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Numerous tests are recently conducted to assess vibration's role in accelerating the heat transfer rate in various heat exchangers. In this work, the enhancement of heat transfer by the effect of transfer vibration and inclination angles on the surface of a double pipe heat exchanger experimentally has been investigated. A data acquisition system is applied to record the data of temperatures, flow rates, and frequencies over the tests. A compound technique was adopted, including the application of a set of inclination angles of (0°, 10°, 20°, and 30°) under the effect of frequency of vibration ranging from sub-resonance to over-resonance frequencies. The results showed that the overall heat transfer coefficient enhan

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Publication Date
Tue Oct 01 2013
Journal Name
Journal Of Economics And Administrative Sciences
Using Benford’s law to detecting earnings management Application on a sample of listed companies in the Iraqi market for securities
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Abstract

The net profit reported in the annual financial statements of the companies listed in the financial markets, is considered one of the Sources of information relied upon by users of accounting information in making their investment decisions. At the same time be relied upon in calculating the bonus (Incentives) granted to management, therefore the management of companies to manipulate those numbers in order to increase those bonuses associated to earnings, This practices are called earnings management practices. the manipulation in the figures of earnings by management will mislead the users  of financial statements who depend on reported earnings in their deci

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Publication Date
Wed Mar 18 2020
Journal Name
Baghdad Science Journal
Spectrophotometric and Reverse Flow Injection Method Determination of Nitrazepam in Pharmaceuticals Using O-Coumaric Acid as a New Chromogenic Reagent
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            A spectrophotometric- reverse flow injection analysis (rFIA) method has been proposed for the   determination of Nitrazepam (NIT) in pure and pharmaceutical preparations. The method is based upon the coupling reaction of NIT with a new reagent O-Coumaric acid (OCA) in the presence of sodium periodate in an aqueous solution. The blue color product was measured at 632 nm. The variation (chemical and physical parameters) related with reverse flow system were estimated. The linearity was over the range 15 - 450 µg/mL of NIT with detection limits and limit of quantification of 3.425 and 11.417 µg mL-1 NIT,respectively. The sample throughput of 28 samples

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Publication Date
Thu Sep 01 2016
Journal Name
Journal Of Ocular Pharmacology And Therapeutics
Formulation and<i>In Vitro</i>Evaluation of Cyclosporine-A Inserts Prepared Using Hydroxypropyl Methylcellulose for Treating Dry Eye Disease
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Publication Date
Mon Aug 05 2024
Journal Name
Pharmacia
A validated spectrophotometric analysis for simultaneous estimation of vincristine sulfate and bovine serum albumin in pure preparations using Vierordt’s method
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The novel Vierordt’s approach, or simultaneous equation method, was created and validated for the concurrent determination of vincristine sulfate (VCS) and bovine serum albumin (BSA) in pure solutions utilizing UV spectrophotometry. It is simple, precise, economical, rapid, reliable, and accurate. This method depends on measuring absorbance at two wavelengths, 296 nm and 278 nm, which correspond to the λmax of VCS and BSA in deionized water, respectively. The calibration curves of VCS and BSA are linear at concentration ranges of 10–60 μg/mL and 200–1600 μg/mL, with correlation coefficient values (R2) of 1 and 0.999, respectively. The limits of detection (LOD) and quantification (LO

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Publication Date
Sun Oct 29 2023
Journal Name
Iraqi National Journal Of Nursing Specialties
Assessment of the Pediatric Nurses' Knowledge about the Nosocomial Infection in the Neonatal Intensive Care Unit of Baghdad Pediatric Teaching Hospitals
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Objectives: To assess the pediatric nurses' knowledge about the nosocomial infection owl), and to fud out the
relatiouships between their knowledge about the nosocomial infection and demographic data.
Methodology: A descriptive study was carried out at neonatal intensive care units OVICUs) of Baghdad
Pediatric Teaching Hospitals. It was started from the end of April to the end of October, 2008. A purposive
sample of (28) pediatric nurses were selected. The data were collected by self-administered questiormaire. The
validity of the questionnaire was detemined through a panel of experts, while its reliability was detemined
through the pilot study. The data were analyzed by descriptive and inferential statistics through th

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