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The Experimental Assessment of R134a and Its Lower GWP Alternative R1234yf in an Automobile Air Conditioning System
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Reducing global warming potential (GWP) of refrigerants is needed to the decrease of ozone-depleting of refrigeration systems leakages. Refrigerant R1234yf is now used to substitute R134a inside mobile air conditioning systems. Thermodynamic properties of R1234yf are similar to R134a. Also, it has a very low GWP of 4, compared to 1430 for R134a, making it a proper choice for future automobile refrigerants. The purpose of this research is to represent the main operating and performance differences between R1234yf and R134a. Experimental analysis was carried out on the automotive air conditioning system (AACS) with 3 kW nominal capacity, to test and compare the performance of R134a with R1234yf. Experiments were accomplished for both refrigerants in almost the same working conditions and procedure with a range of ambient temperature varied from 26oC to 50oC. Parameters studied were ambient temperature, type of refrigerant in the system at compressor speed 1450 rpm, and internal thermal loads of passenger room. The performance characteristics of the system, including COP and cooling capacity, were studied by changing different parameters. The results show that COP of R134a is higher than R1234yf by 12.6%, while the refrigeration effect of R134a is higher than R1234yf by 25%. This shows that R1234yf is a suitable and good candidate for drop-in replacement of R134a in AACS.

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Publication Date
Sun Oct 29 2023
Journal Name
Iraqi National Journal Of Nursing Specialties
Assessment of Quality of life for Patients with Myocardial Infarction
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Objectives: To identify quality of life (QOL) in Myocardial Infarction (MI) patients, and to find out the
relationship between QOL in MI patients and demographic characteristics.
Methodology: A descriptive colTelation study which utilized an assessment approach. The study was carried out
from March 2007 through November 2007 in order to assess the quality of life for patients with myocardial
infarction. A purposive "non-probability" sample of (75) patients with myocardial infarction who were attending
to Baquba General Hospita`l through their visits to that hospital. A questionnaire was adapted and developed
from the World Health Organization Quality of Life Scale (1998). The questionnaire was designed and
consisted

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Publication Date
Sat Jul 08 2017
Journal Name
Research Journal Of Pharmaceutical , Biological And Chemical Sciences
Assessment activity and Partial purification of Alkaline phosphatase (AIP) from sera of patients with celiac disease
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Publication Date
Sun Sep 15 2024
Journal Name
Journal Of Baghdad College Of Dentistry
Assessment of surface microhardness of enamel surface treated with Nano- HAP serum before and after bleaching
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Background: Although bleaching is typically considered a safe procedure, various investigations have found minor negative effects and changes in mineral composition. The aim was to Evaluate and compare the efficacy of using Nanohydroxyapatite serum on surface microhardness of enamel surface before and after bleaching with chemically cured Boost bleaching. Material and methods: ten sound human permanent upper and lower premolar teeth were used and their roots were removed 2 mm apically to the cementoenamel junction, the crowns were sectioned mesiodistally into two halves buccal and lingual/palatal, the buccal surface was further subdivided into two halves. The samples were embeded in an acrylic resin, resulting in 30 specimens divide

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Publication Date
Tue Jun 30 2020
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The role of tax exemption in reducing environmental pollution: An applied study on brick factories in Iraq
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Air pollution is considered one of the major environmental problems that contain many challenges and difficulties facing most countries of the world, including Iraq. The problem has emerged widely with the emergence of the industrial revolution in the world and the tremendous increase in the population and the increase in the number of transportation and its development in addition to excavation, maintenance and work Construction and weather fluctuations, such as dust and sandstorms, pollution resulting from oil refining, extraction, diversion and other processes that cause pollution, and the start of the world using methods that limit the volume of environmental pollution. The most prominent of these methods is the imposition of

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Publication Date
Sun Jan 27 2019
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The Role of Inspection In Achieving Banking Compliance: An Applied Study In A Sample o Iraq Banks
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The Banking Supervision of the most important functions of the Central Bank of Iraq, which he intended to have a strong banking system and a sound and competitive, and exercised control over the banks by inspection bodies to ensure their compliance with the laws, regulations and orders and instructions and the safety of their financial positions.

The research was aimed to release the concept of banking inspection, compliance and problems and obstacles faced by the inspectors, and monitors compliance and down to make recommendations.

Has been reached on a set of theoretical and practical conclusions, including: -

1-confirmed the statistical analysis of the answers to the research sample the importance of the role o

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Publication Date
Fri Dec 29 2017
Journal Name
Al-khwarizmi Engineering Journal
Design And Implementation of Microcontroller Based Curing Light Control of Dental System.
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In this paper, a microcontroller-based electronic circuit have been designed and implemented for dental curing system using 8-bit MCS-51 microcontroller. Also a new control card is designed while considering advantages of microcontroller systems the time of curing was controlled automatically by preset values which were input from a push-button switch. An ignition based on PWM technique was used to reduce the high starting current needed for the halogen lamp. This paper and through the test result will show a good performance of the proposed system.

 

 

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Publication Date
Mon Feb 01 2021
Journal Name
Iop Conference Series: Materials Science And Engineering
Experimental and finite element analysis of mechanical behavior of concrete damaged by Alkali Aggregate Reaction (AAR) and repaired with CFRP Layers
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Abstract<p>Concrete structures is affected by a deleterious reaction, which is known as Alkali Aggregate Reaction (AAR). AAR can be defined as a chemical reaction between the alkali content in the pore water solution of the cement paste and reactive forms of silica hold in the aggregate. This internal reaction produces expansion and cracking in concrete, which can lead to loss of strength and stiffness. Carbon fiber-reinforced polymer (CFRP) is one of the methods used to suppress further AAR expansion and rehabilitate and support damaged concrete structures. In this research, thirty-six cylindrical specimens were fabricated from non-reactive and reactive concrete, which contained fused silica as</p> ... Show More
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Publication Date
Fri Jan 01 2021
Journal Name
Journal Of Engineering
Experimental Study of Electrical and Thermal Efficiencies of a Photovoltaic Thermal (PVT) Hybrid Solar Water Collector with and Without Glass Cover
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Investigating the thermal and electrical gains and efficiencies influence the designed photovoltaic thermal hybrid collector (PVT) under different weather conditions. The designed system was manufactured by attaching a fabricated cooling system made of serpentine tubes to a single PV panel and connecting it to an automatic controlling system for measuring, monitoring, and simultaneously collecting the required data. A removable glass cover had been used to study the effects of glazed and unglazed PVT panel situations. The research was conducted in February (winter) and July (summer), and March for daily solar radiation effects on efficiencies. The results indicated that electrical and thermal gains increased by the incre

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Publication Date
Mon Mar 14 2016
Journal Name
Iraqi Journal Of Market Research And Consumer Protection
Determine the chemical content of Bay (Laurus nobilis L.) leaves extract and its effectivenss against some bacterial species: Determine the chemical content of Bay (Laurus nobilis L.) leaves extract and its effectivenss against some bacterial species
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This study has been performed to study the inhibitory effects of crude plant extracts of Bay (laurus nobilis) leaves against some bacterial isolates represented by Staphylococcus aureus, Staphylococcus epidermids, Proteus vulgaris, Bacillus subtilis, Escherichia coli, and Pseudomonas aeroginosa in vitro. The results showed that percentages of essential chemical of laurus nobilis leaves which represented by moisture, total oil, total ash, crude protein, crude fibers, carbohydrites and caloric values in dry weight are 5.96, 4.28, 14.2, 8.75, 24.8, 76.99%, and 284.92 kcal/100g respectively, the percentages of some major and minor mineral elements of laurus nobilis leaves powder which represented by Mg, Fe, Cu, Pb, Cd and As, are: 0.211, 0.1

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Publication Date
Mon Jan 01 2024
Journal Name
Heliyon
Synthesis and Characterization of Some Metal Ions Complexes with Mixed Ligand of Azo Dye and Metformin and Evaluation of its Effectiveness on the Growth of Some Pathogenic Bacteria Clinically Isolated and Study of its Toxicity on Normal and Cancerous Hepatocytes
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