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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 Sep 01 2024
Journal Name
Baghdad Science Journal
Graphene Oxide Decorated with Nickel Cobaltite Nanoparticles as an Adsorbent for Cationic Methyl Green Dye: Kinetic, Isotherm, and Thermodynamic Studies
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‎تم في هذه الدراسة ، تزيين ‏رقائق أكسيد الجرافين (‏GO‏) بجسيمات ‏كوبلتيت النيكل النانوية ‏NiCo2O4‎‏(‏NC‏) عن طريق الترسيب في ‏الموقع ، وتم استخدام المتراكب ‏المحضر (‏NC: GO‏) كسطح ماز لإزالة ‏صبغة الميثيل الخضراء ( ‏MG‏) من ‏المحاليل المائية. تم التحقق من ‏التغطية الناجحة لأوكسيد الجرافين ‏بجزيئات كوبلتيت النيكل النانوية ‏‏(‏NC‏) باستخدام دراسات ‏FT-IR‏ وحيود ‏الأشعة السينية (‏XRD‏). كانت أحجام  ‏الجسيم

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Publication Date
Tue Jan 02 2018
Journal Name
Journal Of Educational And Psychological Researches
The effectiveness of educational design design according to the theory of Ozbal in the acquisition of geographical concepts among the pupils of the fourth primary in the geography and development of their habits of mind
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Summary The objective of the research is to learn the design of a learning educational learning according to the theory of Ausubel in the acquisition of geographical concepts among the students of the fourth primary in the field of geography and the development of their habits of mind. To achieve this, the researcher relied on the two hypotheses the researcher used the design of equal groups the first experimental group was studied according to the design educational educational learning according to the theory and the other is an officer according to the traditional method. The research community consists of fourth grade pupils in primary school day for girls in the Directorate of Education Baghdad, Al-Rusafa, the third academic year 20

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Publication Date
Sun Feb 22 2026
Journal Name
Journal Of The College Of Basic Education
The effect of rehabilitation exercises with different resistances in the water medium according to some variables and biomechanics in restoring the flexibility and strength of the thigh muscles for those with knee roughness
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It included the introduction to the research and its importance, as the knee joint is one of the important joints in the human body that are susceptible to injury, and among these injuries is the roughness of the knee that occurs as a result of weakness and imbalance in the work of the quadriceps muscle, so its treatment is through rehabilitation exercises to treat weakness and gain flexibility and strength.Hence the importance of the research by developing rehabilitation exercises with different resistances in the water medium and restoring flexibility and muscular strength for patients with knee roughness for ages from 30-40 years, and the experimental method was used to solve the research problem, and the research sample included (6) of

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Publication Date
Wed Jun 07 2023
Journal Name
Journal Of Educational And Psychological Researches
A Proposed Training Program for School Leaders in the Sultanate of Oman on the Planning Practices of the Kaufman Model in Light of the Needs and Challenges of Reality
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The study aims to build a proposed training program for school leaders in the Sultanate of Oman on the planning practices of the Kaufman model in light of the needs and challenges of reality. It also aims to identify the challenges facing school leaders in practicing the stages of strategic planning. To achieve these objectives, the study adopted the descriptive approach due to its suitability to the nature of the study. A questionnaire was used to collect the needed data. The study sample included (225) individuals from school principals, their assistants and senior teachers in post-basic education in the Sultanate of Oman. After processing the data statistically, the study concluded that the reality of planning practices for school lea

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Publication Date
Wed Aug 26 2020
Journal Name
Iraqi Journal Of Agricultural Sciences
MEASURING THE ECONOMIC EFFICIENCY AND TOTAL PRODUCTIVITY OF RESOURCE AND THE TECHNICAL CHANGE OF AGRICULTURAL COMPANIES IN IRAQ USING SFA AND DEA FOR THE PERIOD 2005-2017
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The research aims to measure the economic efficiency and technological change and the total productivity of resources using the parameter and non-parameter methods, for agricultural companies registered in the Iraqi stock exchange, the number of 6 companies for the period from 2005 to 2017 based on the hypothesis that the  agricultural companies do not achieve economic efficiency and does not control the management of its operations, and It may be technically efficient but the size of its operations is not optimal. From non-parametric methods, the data envelope analysis method was used. Using the DEAP program, the Middle East Company achieved the highest average technical and cost efficiency of 0.62 and 0.58, respectively. The Iraq

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Publication Date
Wed Apr 01 2015
Journal Name
Journal Of Pharmaceutical, Chemical And Biological
Isolation of Candida Spp. from Patients with Different Types of Leukemia Who Suffered Oral Candidiasis Due to Their Weekend Immune System
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The study is concern on determine the type of Candida spp.in leukemia patients that were infected with oral candidiasis as a result to their immune suppression (weekend immune system) due to their submission to radiation and chemotherapy treatment. The result showed that the most common isolates were C. guillermondii 19 which represent 31.66% of cases, then followed by C. itermedia 11 which represent 18.3%, while the less common isolates were for C. zeylamodes 3 which represent 5%.

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Publication Date
Sun Feb 22 2026
Journal Name
Al.qadisiya Journal For The Sciences Of Physical Education
The Influence of Using Special Exercises with Weights to Develop Moments of Force to Some of the Striking Shoulder and Arm Muscles and Accuracy of the Skill of the Smash and Rectum in Volleyball
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This research is an attempt to develop exercise with weights to strengthen some of the striking muscles in the shoulder and arm and to develop the accuracy of the smash and rectum skills. The importance of this paper lies in the study of moments of force to achieve the ability to control muscular work and to explore the impact of physical and skill exercises with weights to develop moments of force for some muscles. The experimental method on a sample of players, selected according to the intentional method, including ( 9) advanced players representing Air Force Club participating in the Premier League for season 2011-2012. It is concluded that the exercises proposed have their effective impact on developing the variables of moments force f

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Publication Date
Sat Apr 02 2022
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Impact of Contractual Budget In Support Of Sustainable Development Applied Research In The Ministry Of Housing And Construction And Public Municipalities
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The research starts from studying the contractual budget, which is one of the modern trends in preparing public budgets, both operational and capital, in addition to meeting the requirements of the global trend to achieve sustainable growth in all fields, whether financial or non-financial, and tools for the contractual budget have been identified (participation contracts, planning Implementation, monitoring) and studying its impact in supporting sustainable development through its dimensions (economic, social, and environmental). The method of the questionnaire was adopted as a main tool in collecting information on research variables and distributing it to a sample of (70) individuals who dictate positions of professional respo

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Publication Date
Mon Oct 01 2018
Journal Name
Journal Of Educational And Psychological Researches
Media concepts in social studies and national textbooks in public education in light of media education standards and the nature of Saudi society
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The study aimed to reveal the degree of inclusion of media concepts in the books of social and national studies in general education in light of the criteria of media education and the nature of the Saudi society. Additionally, to identify the estimations of the participants in the study of the importance of including media concepts in these books, and to build a matrix of the range and sequence of media concepts in the books of social and national studies in the grades of Saudi general education. The study followed the descriptive approach in both descriptive analysis of the textbooks and descriptive survey of the study participants who were (203) students in the schools of boys and girls in general education in Makkah. The study used t

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Publication Date
Sun Jun 03 2012
Journal Name
Baghdad Science Journal
Study the effect of the mixture aquatic extract of Peganum harmala seeds and Pericarp of Punica granutum on viability of protoscolices of Echinococcus granulosus in vitro and in vivo
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This study included the preparation of the mixture aquatic extracts of Peganum harmala seeds and Pericarp of Punica granutum at concentration (10+50) ?(15+55)? (20+60) mgml .To study the influence of the mixture on the percentage of vitality of the protoscolices of E. granulosus In vitro, as the vitality of protoscolices had caused complete death when the using concentration at time 120,90,60 minute respectively. Also study the effect of mixture in white mice with infectious protoscolices In vivo and study the change occurred in the averages of the weights of the liver and spleen and the averages of its distension In vivo in processed group with mixture at concentration (15+55) , (10+50)mgml ,as which was approach to the negative gro

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