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Investigation of R134a Flow Boiling Heat Transfer and Pressure Drop in the Evaporator Test Section of Refrigeration System
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This paper presents an experimental and theoretical analysis to investigate the two-phase flow boiling heat transfer coefficient and pressure drop of the refrigerant R-134a in the evaporator test section of the refrigeration system under different operating conditions. The test conditions considered are, for heat flux (13.7-36.6) kW/m2, mass flux (52-105) kg/m2.s, vapor quality (0.2-1) and saturation temperature (-15 to -3.7) ˚C. Experiments were carried out using a test rig for a 310W capacity refrigeration system, which is designed and constructed in the current work. Investigating of the experimental results has revealed that, the enhancement in local heat transfer coefficient for relatively higher heat flux 36.6 kW/m2 was about 38% compared to 13.7 kW/m2 at constant operating conditions. The enhancement in heat transfer coefficient was about 57% when the mass flux increased from 52 kg/m2.s to 105 kg/m2.s at constant test conditions. The enhancement in the heat transfer coefficient was about 64% when the saturation temperature increased from -8 to -3.7 at fixed refrigerant mass velocity and heat flux. The effect of mass velocity on pressure drop was relatively higher by about 27% than that for heat flux at specified test conditions. The comparison between the experimental and theoretical results has shown an acceptable agreement with an average deviation of 21%.

 

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Publication Date
Sat Dec 15 2018
Journal Name
Journal Of The College Of Education For Women
The Reasons for the Behavior of Bullying school Students in the first grade average from the point of view of teachers and teachers and methods of modification
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 هدف البحث التعرف الى اسباب سلوك التنمر لدى طلاب الصف الاول المتوسط من وجهة نظر المدرسين والمدرسات واساليب تعديله، واستعمل الباحثان المنهج الوصفي واختيار عينة عشوائية من المدرسين والمدرسات في متوسطة أرض الرافدين ومتوسطة الرحمن للبنين وكان عددهم (46) مدرساً ومدرسة بواقع (32) مدرساً و(14) مدرسة، واعتمد الباحثان الاستبانة أداة للتعرف الى اسباب سلوك التنمر واساليب تعديله، واشارت نتائج البحث الى تنوع اسباب التن

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Publication Date
Mon Mar 07 2022
Journal Name
Journal Of Educational And Psychological Researches
The impact of the Roundtable and Self-Questioning strategies on achievement and self-efficacy For students of the Faculty of Education in the subject of research curricula
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The current research aims to identify "the impact of the round table strategies and the question of self-achievement and self-efficacy among students of the Faculty of Education in research methodology course.” The research sample consisted of (75) male and female-third stage students in the department of Life Sciences / College of Education for Pure Sciences / University of Dhi Qar for the academic year (2018-2019. The researcher adopted the experimental approach to achieving the study objectives. The researcher prepared two tools: the achievement test and the self-efficacy scale were applied to the collected sample to obtain the needed data. The result showed that there was a statistically significant difference at the level (0.05) b

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Publication Date
Mon Mar 07 2022
Journal Name
Journal Of Educational And Psychological Researches
The Effectiveness of Cognitive Conflict Strategy in Comprehending Reading Among the Fifth Literary Students in the Subject of Literature and Texts
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The aim of the current study is to identify the effectiveness of cognitive conflict strategy in comprehending reading among literary fifth students in literature and literature texts. The researcher uses experimental method with partial control. The sample consisted of (80) students distributed into control and experimental groups. The scientific material, the behavioral goals, the teaching plans, and the instrument of the research have been prepared (reading comprehension test) by the researcher.

The instrument's validity and reliability have been calculated and then applied to the sample. After treating the data statistically by using SPSS, the results have revealed that there is a statistically significant difference at the si

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Publication Date
Sun Jul 02 2017
Journal Name
Journal Of Educational And Psychological Researches
The Effect of Carin Model in The Achievement of The First Intermediate Grade Students and Their Reflective Thinking in Physics Subject.
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The Current research aims to identify ( the effect of Carin model in the achievement of the first intermediate Grade Students and their Reflective Thinking in physics Subject ) the researcher selected the experimental design with a partial adjust , The research sample consisted of ( 47 ) Students with ( 23 ) Students in the experimental group and ( 24 ) Students in the control group , The two groups rewarded in the variables chronological age in months , Reflective Thinking and the degrees in physics in the first course. The researcher coined the purposes of behavioral which belong to chapter fifth, sixth, and seventh of physics books scheduled of the school year ( 2015-2016 ) and prepared appropriate lesson plans for the two experimenta

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Publication Date
Sat Sep 01 2012
Journal Name
Journal Of Economics And Administrative Sciences
Studying and analysis effect level of the Government expenditure and Gross Domestic product in size of the expenditure on the higher education in Iraq (1995 – 2009)
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The education, especially higher education, is an essentially factor in the progress of any society, if we consider the higher education, represents the top  of  the education`s  pyramid which take part in developing the human  resources and provide the human staff to raise the productive efficiency, and improve the social , economic level                                  

In order to face the increasing importance of higher education, great capabilities and expenditures must be available in a continous way, such expe

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Publication Date
Wed Mar 10 2021
Journal Name
Baghdad Science Journal
The impact of the lack of certain vitamins and minerals intake rate of hair loss in pregnant and breastfeeding women
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The research aims to identify the rates of hair loss during pregnancy and lactation and its relation to the rates get some elements motivator urged through the results of the continued failure to meet the need of daily assessments of these elements, which led to the continuation of Hair Loss

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Publication Date
Wed Mar 15 2023
Journal Name
Al-academy
The Developed Materials and Techniques and Its Role in Exposing the Aesthetic Of Art Work
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This study is targeting the new developed materials and techniques and how they were affected by the scientific and technological developments that contributed to revelated new and varied developed materials and techniques. And from the artist’s formulation by using the materials and techniques and through its embodiment and sensor the values, artistic and aesthetic standards by breaking from the familiar in aesthetic contemporary way.
The studies on questioning what’s the role of The New Developed Materials and Techniques in exposing the aesthetic of the art work?

This study is to show the aesthetic of the art work through the new developed materials and techniques. Which was based on descriptive analyzing method and hig

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Publication Date
Fri Jun 20 1930
Journal Name
College Of Islamic Sciences
Prison and imprisonment   And their impact on the strengthening of power In the Qur'anic perspective
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Prison and imprisonment  
And their impact on the strengthening of power
In the Qur'anic perspective

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Publication Date
Thu Dec 30 2021
Journal Name
College Of Islamic Sciences
The Trilogy of Punishment - The Great, Painful and Humiliating in the Holy Quran An objective study: The Trilogy of Punishment - The Great, Painful and Humiliating in the Holy Quran An objective study
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The study of triples seeks to deal with the comprehensive nature of the Qur’an texts, and the choice fell on the trilogy of great torment, pain, and humiliation in the Noble Qur’an - an objective study, the title of this research, in which I tried to shed light on these terms, and the nuances between them, and in particular torment The eschatological terminology varied, which can be summed up in three terms, namely the great, the painful, and the offensive. The types of torment, the pain is the painful one that is described by the severity of pain and its horror, as for the humiliating punishment, it is that which humiliates the one who has fallen on it, and the diversity of torment is due to the diversity of sins.

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Publication Date
Sun Feb 03 2019
Journal Name
Journal Of The College Of Education For Women
The Image of the Soldier in Brendan Behan's The Hostage And Charles Fuller's A Soldiers Play: The Image of the Soldier in Brendan Behan's The Hostage And Charles Fuller's A Soldiers Play
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Abstract
The image of the soldier, as a hero who sacrifices everything to defend his
country and values, is no longer depicted in modern drama. With two World Wars
and many regional wars and civil wars, the soldier becomes a victim, not a hero.
Authors present the character of the soldier as a man who suffers a lot as he is
victimized by his own government and its politics that forces him to be in such a
position. Dramatists express their views about race, oppression and war through
their characters, such as the character of the soldier, as in the two selected plays for
this research: The Hostage by Brendan Behan and A Soldier's Play by Charles
Fuller.
The Hostage depicts, through its events, the Irish oppre

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