Preferred Language
Articles
/
YBim3JYBVTCNdQwCuoek
Assessment of using different ozone-friendly R22 alternative refrigerants in residential air conditioners in a high-ambient temperature country
...Show More Authors
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>
Scopus Crossref
View Publication
Publication Date
Tue Jan 03 2023
Journal Name
The Egyptian Journal Of Hospital Medicine
High Tumor Levels of Ki-67, VEGF and Endostatin Are Associated with Progression of Breast Cancer in Iraqi Women
...Show More Authors

Background: Breast cancer (BC) is the most widespread cancer among women worldwide. Its incidence and mortality rates have risen in the previous three decades as a result of changes in risk factor profiles, improved cancer registry, and cancer detection. Objective: The study's goals were to establish if Ki-67 could be used as a potential marker in serum of cancer disease patients as well as their interaction with vascular endothelial growth factor (VEGF) and ES in various stages of breast cancer to assess their function in the progression of BC. Materials and Methods: The levels of Ki-67, VEGF and endostatin (ES) in serum were assessed by commercial enzyme linked immunosorbent assay (ELISA) kits in 60 women diagnosed with breast cancer

... Show More
Preview PDF
Crossref
Publication Date
Wed Apr 27 2022
Journal Name
Arabian Journal For Science And Engineering
Optical and Thermal Performance of a Parabolic Trough Collector for Different Receiver Geometries
...Show More Authors

This paper numerically and theoretically investigates the optical and thermal performance of a parabolic trough collector PTC system. Many numerical simulations and theoretical analyses are conducted to demonstrate the influence of the receiver geometry and shifting from the focal position on the optical performance. The examined receiver geometries are circular, square, triangular, elliptical, and the new circular–square combined geometry is named as channel receiver. The thermal performance of PTC is examined for different volume flow rates theoretically in the range of (0.36 to 2.4 lpm). The results show that the best optical design is the channel receiver with an intercept factor of 84%, while the worst is the elliptical receiver with

... Show More
View Publication
Scopus (19)
Crossref (11)
Scopus Crossref
Publication Date
Thu Dec 01 2022
Journal Name
Journal Of Engineering
The Effectiveness of a Simulation Model of Thermal Insulation in Building Materials Using Cellulose Extracted from Agricultural Waste in Baghdad
...Show More Authors

This study found that one of the constructive, necessary, beneficial, most effective, and cost-effective ways to meet the great challenge of rising energy prices is to develop and improve energy quality and efficiency. The process of improving the quality of energy and its means has been carried out in many buildings and around the world. It was found that the thermal insulation process in buildings and educational facilities has become the primary tool for improving energy efficiency, enabling us to improve and develop the internal thermal environment quality processes recommended for users (student - teacher). An excellent and essential empirical study has been conducted to calculate the fundamental values ​​of the

... Show More
View Publication Preview PDF
Crossref (2)
Crossref
Publication Date
Fri Mar 15 2019
Journal Name
Journal Of The College Of Education For Women
The Impact of Anticyclones Merge on the Temperature in the stations of Mosul, Baghdad and Basra for the Period (2005-2015)
...Show More Authors

           The Anticyclone Merge affects Iraq’s climate clearly through its impact on the different climatic elements. where it appears while they pass through special and distinctive weather . and most of this affection appears in temperatures, Therefore, this research study the relationship between the repetition and the survival period of the Anticyclone Merge and temperature average by using coefficient correlation (Pearson) that shows there’s strong inverse relationship between the integration of Anticyclones and temperatures average.                        &nbs

... Show More
View Publication Preview PDF
Publication Date
Mon Jun 08 2026
Journal Name
Journal Of Baghdad College Of Dentistry
Evaluation of shear bond strength of artificial teeth to heat cure acrylic and high impact heat cure acrylic using autoclave processing method
...Show More Authors

Background: Debonding and fracture of artificial teeth from denture bases are common clinical problem, bonding of artificial teeth to heat cure acrylic and high impact heat cure acrylic denture base materials with autoclave processing method is not well known. The aim of this study was to evaluate the effect of autoclave processing method on shear bond of artificial teeth to heat cure denture base material and high impact heat cure denture base material. Materials and methods: Heat polymerized (Vertex) and high impact acrylic (Vertex) acrylic resins were used. Teeth were processed to each of the denture base materials after the application of different surface treatments. The sample (which consist of artificial tooth attached to the dentur

... Show More
View Publication Preview PDF
Publication Date
Thu Nov 28 2024
Journal Name
Journal Of Emergency Medicine, Trauma And Acute Care
Assessment of practices and attitudes of undergraduate students toward family violence in the University of Baghdad
...Show More Authors

Objectives: The aim of this study was to assess undergraduate student's practices and attitudes toward family violence in the University of Baghdad.

Methods: This was a descriptive study on non-probability (purposive) sample of 100 undergraduate students from different colleges at the University of Baghdad from November 15, 2022 to May 20, 2023. A validated questionnaire was prepared with 43 questions, which consisted of three parts: eight items related to students’ demographic data, 13 items related to students’ attitudes, and 22 items related to students’ practices.

... Show More
View Publication
Scopus (3)
Crossref (2)
Scopus Crossref
Publication Date
Wed Dec 30 2020
Journal Name
Biodiversitas Journal Of Biological Diversity
Assessment of some heavy metals in various aquatic plants of Al-Hawizeh Marsh, southern of Iraq
...Show More Authors

Abstract. Al-Abbawy DAH, Al-Thahaibawi BMH, Al-Mayaly IKA, Younis KH. 2021. Assessment of some heavy metals in various aquatic plants of Al-Hawizeh Marsh, southern of Iraq. Biodiversitas 22: 338-345. In order to describe the degree of contamination of aquatic environments in Iraq, heavy metals analysis (Fe, Ni, Cr, Cd, Pb, and Zn) was conducted for six aquatic macrophytes from different locations of Al-Hawizeh Marsh in southern Iraq. The six species were Azolla filiculoides (floating plant), Ceratophyllum demersum, Potamogeton pectinatus, Najas marina (submerged plants), Phragmites australis, and Typha domingensis (emergent plants). The results indicate that cadmium, chromium, and iron concentrations in aquatic plants were above the

... Show More
View Publication
Scopus (16)
Crossref (1)
Scopus Crossref
Publication Date
Wed Dec 18 2019
Journal Name
Baghdad Science Journal
A Modified Approach by Using Prediction to Build a Best Threshold in ARX Model with Practical Application
...Show More Authors

The proposal of nonlinear models is one of the most important methods in time series analysis, which has a wide potential for predicting various phenomena, including physical, engineering and economic, by studying the characteristics of random disturbances in order to arrive at accurate predictions.

In this, the autoregressive model with exogenous variable was built using a threshold as the first method, using two proposed approaches that were used to determine the best cutting point of [the predictability forward (forecasting) and the predictability in the time series (prediction), through the threshold point indicator]. B-J seasonal models are used as a second method based on the principle of the two proposed approaches in dete

... Show More
View Publication Preview PDF
Scopus (1)
Scopus Clarivate Crossref
Publication Date
Wed Jan 01 2020
Journal Name
Annals Of Tropical Medicine And Public Health
Phytochemical investigation And high performance thin layer chromatography (HPTLC) identification of flavonoids and phenolic acids in Euphorbia cyathophora (Family: Euphorbiaceae) cultivated in Iraq
...Show More Authors

View Publication
Crossref (1)
Crossref
Publication Date
Mon Jun 08 2026
Journal Name
Journal Of Baghdad College Of Dentistry
Aging effect of different types of composite resin restoration on shear bond strength to different orthodontic adhesives with sapphire bracket (In vitro comparative study)
...Show More Authors

Background: This study was performed to determine the effect of aging of different types of composite material restorations on: Shear bond strength (SBS) to light cure and no mix chemical cure orthodontic adhesives with sapphire bracket and the debonding failure sites. Materials and methods: One hundred forty four composite disks were made from three different composite resin materials which are: 3M Filtek Z250, 3M filtek Z350 and 3M Valux plus, each group with (48) disks each, then according to the duration of storage each group was subdivided into two equal groups one of them stored for one day and the other was stored for one month, then each group was further subdivided into two equal subgroups with (12) disks each one bonded with ligh

... Show More
View Publication Preview PDF