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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
Wed Sep 01 2021
Journal Name
Baghdad Science Journal
Studying the Magnetohydrodynamics for Williamson Fluid with Varying Temperature and Concentration in an Inclined Channel with Variable Viscosity
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        In this paper, the Magnetohydrodynamic (MHD) for Williamson fluid with varying temperature and concentration in an inclined channel with variable viscosity has been examined. The perturbation technique in terms of the Weissenberg number  to obtain explicit forms for the velocity field has been used. All the solutions of physical parameters of the Darcy parameter , Reynolds number , Peclet number  and Magnetic parameter  are discussed under the different values as shown in plots.

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Publication Date
Fri Jan 01 2016
Journal Name
Journal Of College Of Education
An Investigative Study on the Electron Energy Distribution Function and Electron Transport Coefficients in SF6 -- Ne Gas Mixtures
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Publication Date
Sun Sep 26 2021
Journal Name
Modern Sport
Decision-making and its relationship to spiking and blocking performance in volleyball for emerging players
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The game of volleyball is one of the competitive team games that took the lead in terms of its spread in the world, and the game of volleyball relies on basic skills as an important base on which this game is built to advance in the level of performance Performance and among these skills the skill of spiking and blocking wall, the research aims to identify the extent of the relationship of decision-making to the performance of spiking and blocking in volleyball for junior players. The sample was chosen from volleyball players for the Junior Specialized School of Sulaikh Sports Club / Baghdad Governorate for the season 2020 The researcher used the descriptive approach, and the research community was composed of (101) players. The two

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Publication Date
Sat Jan 12 2019
Journal Name
Journal Of The College Of Education For Women
Strategic Analysis for the Grain Grinders' establishments in Baghdad governorate and problems suffered by the industry, along with the possibility to predict its products
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Geography of industry has been considered a branch of important economic geographical branches. This importance has been regarded as a reflection on the industrial sector contribution in economies of any state since they contribute into the total national product ; it also assimilates a huge number of labor hands . The industry of grains grinding has been considered as one of the main food industries having a main role in satisfying the need of the population from the foods. The industry is continued to use the food as daily meal . Here, it should predict the population in Baghdad and for every district until the end of 2025 and knowing either these grains grinders are able to meet and satisfy the needs of populations of flours, making s

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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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Publication Date
Sun Sep 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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Publication Date
Fri Jan 01 2016
Journal Name
Journal Of College Of Education
Some of the Probability Characteristics Functions of the Solution of a System of Random Linear Inequalities
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Publication Date
Tue Dec 01 2015
Journal Name
Journal Of Economics And Administrative Sciences
Organizational Red Tapes and their Reflections on Entrepreneurial Orientation: an Exploratory Study of a Sample of Employees in Some Organizations in the Province of Ninewah
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Organizations adopt a number of procedures and instructions in their field of activities in order to aid their resources development   and energies to serve their entrepreneurial orientations. This calls for preparing a range of mechanisms to mitigate the strictness and complexity of procedures. The ambiguity and severe  complexity  of procedures means acknowledging the loss in energy and this in turn  impedes the hopes while in the same time weakens the  enthusiasm in these organizations and an impedes the possibility to achieve continues innovation, thereby losing opportunities to the level of surrender to the risks and  assuming them to be unconquered obstacles.

There

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Publication Date
Sun Apr 06 2014
Journal Name
Journal Of Educational And Psychological Researches
Positive thinking and its relation to self academic motivation and the trend towards teaching profession among the students of education colleges
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The research aims to know the relation between positive thinking and self academic motivation, trend towards teaching profession. So a sample of (344) male and female student of the morning study of education colleges from the two universities of Baghdad and al Mustansria for the academic year 2012-2013.

So three tools had been used to achieve the procedures of the research which are: the scale of positive thinking constracted by Abdal satar Ibrahim year 2010, the scale of self academicmotivation constracted by (Gottfried) and adapted by Hanan Hussan year 2010, the scale of teaching profession trend constracted by Enayat Zaki year 1974.

And by using the statistical means of person

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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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