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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
Tue Feb 24 2026
Journal Name
Journal Of Baghdad College Of Dentistry
An Evaluation of Olive Oil as a Separating Medium and Its Effect on Some Mechanical Properties of Processed Acrylic Resin Denture Base (A Comparative Study). Part Two
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Background: During acrylic resin processing, the mold must be separated from the surface of the gypsum to prevent liquid resin from penetrating into the gypsum, and water from the gypsum seeping into the acrylic resin. For many years, tin foil was the most acceptable separating medium, and because it's difficult to apply, a tin-foil substitute is used. In this study, olive oil is used as an alternative to tin foil separating medium for first time, and evaluating its effect as a separating medium on some mechanical properties such as (indentation hardness and transverse strength) of acrylic resins denture base comparing it with those processed using tin-foil and tin foil substitute such as (cold mold seal) separating medium. Materials and M

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Publication Date
Fri Feb 15 2019
Journal Name
Journal Of Theoretical And Applied Information Technology
A system for rapid localization and intensity evaluation of saponins accumulation in plant tissues
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A fluorescence microscopy considered as a powerful imaging tool in biology and medicine. In addition to useful signal obtained from fluorescence microscopy, there are some defects in its images such as random variation in brightness, noise that caused by photon detection and some background pixels in the acquired fluorescence microscopic images appear wrongly auto-fluorescence property. All these practical limitations have a negative impact on the correct vision and analysis of the fluorescent microscope users. Our research enters the field of automation of image processing and image analysis using image processing techniques and applying this processing and analysis on one of the very important experiments in biology science. This research

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Publication Date
Tue Feb 24 2026
Journal Name
Al–bahith Al–a'alami
DICTION (IN ARAB SATELLITE CHANNELS) A SIGNAL SYSTEM : (study of written And oral patterns)
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Communication has seen a big advancement through ages; concepts, procedures and technologies, it has also seen a similar advancement of language. What unites language and media is the fact that each one of them guides and contributes to the other; media exists and results from language and from the other sign systems, and what strengthens this connection is the symbolic language system, as media helps it by providing knowledge and information. The change that occurred through time must leave a significant trace in the media, for example Diction, which has changed concerning development and growth, also the ways and mediums of media have become manifold and widespread. This change affected the recipient whether it was a reader, listener o

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Publication Date
Sat Dec 28 2024
Journal Name
Journal Of Physical Education
The effect of using special intense exercise accompanied by intermittent electrical stimulation to get rid of lower neck pain among professors of the College of Science - University of Baghdad for ages (40-60) years
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Lower neck pain is one of the problems facing all ages, especially the elderly, as it revolves around the causes of this pain from many diverse factors. The aim of the research is to use special intense exercise accompanied by intermittent electrical stimulation to get rid of lower neck pain among professors of the College of Science - University of Baghdad for ages. (40-60) years and to identify the extent of the effect. The research assumed the presence of statistically significant differences. The research sample represented professors at the University of Baghdad - College of Science who suffer from continuous pain for the period between (10/15/2023) and (1/15/) 2024) and their number is (5), The researchers used the experimenta

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Publication Date
Sun Feb 03 2019
Journal Name
Journal Of The College Of Education For Women
The Relationship Between Blood Types And The Kind Of Food Intake And Its Impact on Human Health
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This Study aimed To know The relation between Types of blood and health problems which human Suffered from , and the effect of food intake on health.
Samples of study contained 269 person aged between 30 – 70 years which choiced randomly for sex , we are take all in formation about samples of study by form paper contian sex , age, type of blood , weight (kg) , height (cm) , smoking or.not , sporting or not, problems in digestive tract , sensitivity for foods , heart problems , ratio of cholesterol in blood , Sinusitis , Asthma , diabetic meliuts , arritable bowel syndrome , diaherra , problems in kidney and urination , hypertension , anemia , alternation in liver function , arthritis with form record in daily food intake and its ade

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Publication Date
Tue Aug 15 2023
Journal Name
Journal Of Economics And Administrative Sciences
Inclusive leadership in the General Secretariat for the Council of Ministers - An analytical research
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The current research aims to evaluate the level of inclusive leadership within the General Secretariat for the Council of Ministers, and its role in achieving integration in work through the need to improve relationships between different administrative levels, facilitate participation, expression of opinions, and belonging to the organization. In order to achieve the research objective, the descriptive analytical statistical method was chosen using the SPSS V.25 programs, with various statistical methods and measures, including mean, standard deviation, variance coefficient, relative importance, and simple regression, through a questionnaire tool for data collection. The research community included the leadership in the sample of resear

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Publication Date
Fri Apr 30 2021
Journal Name
Onkologia I Radioterapia
The prevalence of lymph proliferative disorders in a group of Iraqi patients and its relation to blood indices parameters
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Abstract: Lymphoproliferative Disorders (LPDs) are a group of neoplasms affecting various cells within lymphoid system. Each type has different treatment a..70619

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Publication Date
Wed Jan 01 2020
Journal Name
Journal Of Mechanical Engineering Research And Developments
The perfect position of electrical components on PCBs in communication system industry from the mechanical aspects' viewpoint
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Publication Date
Mon Dec 11 2017
Journal Name
Al-khwarizmi Engineering Journal
Study the Characterization of Adding Polymer-Surfactant Agent on the Drag Reduction Phenomena in Pipeline Flow System
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  Abstract    

In this study, the effect of carboxylic methyl cellulose (CMC), and sodium dodcyl benzene sulfonate (SDBS) as an aqueous solution on the drag reduction was investigated. Different concentrations of (CMC) and (SDBS) such as (50, 100, 150, 200, 250, 300, 350, 400, 450, and 500 ppm) were used to analyze the aqueous solution properties, including surface tension, conductivity, and shear viscosity. The optimum four concentrations (i.e., 50, 100, 200, and 300 ppm) of fluid properties were utilized to find their effect on the drag reduction. Two different PVC pipe diameters (i.e., 1" and 3/4") were used in this work. The  results showed that blending CMC with SDBS gives

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Publication Date
Sun Aug 30 2020
Journal Name
Journal Of Economics And Administrative Sciences
The role of organizational symmetry in improving the quality of work life an applied research at the University of Information and Communications Technology
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"The aim of the research is to identify the availability of the dimensions of the research variables represented by organizational symmetry and the quality of work-life at the University of Information and Communications Technology, which is one of the formations of the Ministry of Higher Education and Scientific Research in Baghdad, in addition to knowing the relationship and influence between them. The research relied on the descriptive analytical approach based on peer description. The research was analyzed and the research sample consisted of (148) individuals, the sample was chosen using the comprehensive inventory method, data was obtained by relying on the questionnaire which was prepared from ready-made m

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