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Experimental Study on the Effect of Insertion of Copper Lessing Rings in Phase Change Material (PCM) on the Performance of Thermal Energy Storage Unit
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Abstract

One of the most suitable materials to be used in latent heat thermal energy storage system (LHTES) are Phase change materials, but a problem of slow melting and solidification processes made many researchers focusing on how to improve their thermal properties. This experimental work concerned with the enhancing of thermal conductivity of phase change material. The enhancing method was by the addition of copper Lessing rings in phase change material (paraffin wax). The effect of diameter for the used rings was studied by using two different diameters (0.5 cm and 1cm). Also, three volumetric percentages of rings addition (3%, 6% and 10%) were tested for each diameter. The discharging process was done with four velocities for each case. The obtained results indicated that the maximum volumetric percentage gave a diminished time for melting and maximized the heat transfer in both PCM and air sides as compare with the case of no rings, but the effect of these rings had lower effect on the solidification time. In case of 1 cm rings diameter minimum time for melting was obtained for both 3% and 6% volumetric percentages as compared with the same percentages in case of 0.5 cm diameter rings, while the latter with 10% volumetric percentage overcomes the 1 cm diameter rings for the same previous percentage. Also it can be seen that the minimum velocity (v=1m/s) gave the utmost outlet temperature and with the maximum one (v=3m/s), the minimum solidification time achieved.

Keyword: Thermal energy storage systems, Latent heat storage, Phase change materials, Heat transfer enhancement.

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Publication Date
Wed Dec 20 2023
Journal Name
Arab Science Heritage Journal
بعض وظائف النبي صلى هللا تعالى عليه وآله وصحبه وسلم الواردة في القرآن الكريم
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The research included an introduction, and three functions
of the Prophet (peace and blessings of Allaah be upon him), a
machine and a companion, and a conclusion , the first function,
which is zakaah, and began with it because it is the basis of every
work, no work is accepted by Allaah except what was sincere to
him, as well as sincere intention, because accepting works is
entrusted with the

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Publication Date
Mon Dec 01 2008
Journal Name
Journal Of Economics And Administrative Sciences
قياس وتحليل تفاعل عمل المضاعف والمعجل في الاقتصاد العراقي باستخدام نموذج المستخدم – المنتج الديناميكي
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The individual average income is considered one of the most used criteria for the distinguishing between the developed and the developing countries, for this reason the efforts of economic development has been construed on increasing the average national income, the investment expenditures is considered one of the basic foundations for economic development operation which lead to the expanding the prodection power of the economy, and increasing the level of national income in an averages greaten than the primary expenditures due to the work and interaction between the multiplier and the accelerator. But the ability of the economic sectors in the generation of national income as a result of the primary expenditures is different fr

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Publication Date
Tue Feb 01 2022
Journal Name
Baghdad Science Journal
Milk Tumor Necrosis Factor Alpha and Interleukin-1Beta Among Toxoplasma gondii-Free and Infected Women
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Pro-inflammatory cytokines play an important role in intercellular communications. In the last two decades, many cytokines have been identified in human milk. These cytokines are variable according to different conditions such as pathogenic infections which strongly stimulated the immune response. The present study aims to determine of IL1β and TNF-α in Toxoplasma gondii-free and infected women in an attempt to clarify the impacts of the infections on cytokines especially in mother's milk. The serum and milk sample were collected from 96 samples (48 for seropositive and 48 for seronegative). To confirm the Toxoplasma gondii infection; enzyme linked immunofluorescence assay (ELIFA) was used to detect anti-Toxoplasma Ig

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Publication Date
Sun Apr 03 2011
Journal Name
Journal Of Educational And Psychological Researches
اثر الانموذج المعملي في تصحيح المفاهيم الرياضية شائعة الخطأ لدى طلاب الصف الاول المتوسط
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ملخص الدراسة
سعت الدراسة تعرف اثراستعمال الأنموذج المعملي في تصحيح المفاهيم الرياضية شائعة الخطأ لدى طلاب الصف الأول المتوسط بالإجابة عن السؤال "ما اثر استعمال الأنموذج المعملي في تصحيح المفاهيم الرياضية شائعة الخطأ لدى طلاب الصف الأول المتوسط" ولتحقيق هدف الدراسة وضعت الفرضية الصفرية "لايوجد فرق ذو دلالة إحصائية عند مستوى الدلالة (0.05) بين متوسطي درجات طلاب المجموعة التجريبية الذين يدرسون المادة المقرر

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Publication Date
Sun Jun 01 2008
Journal Name
Journal Of Economics And Administrative Sciences
منظمات الاداء العالي بحث أستطلاعي في الشركة العامة للصناعات الجلدية والشركة العامة لتصنيع الحبوب
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This study discussed modern variable in the organizational thought that is the high performance organizations in the two of Iraqi public organizations. The aim of study determines to know the level of the performance in this organizations (high or not). The data was Collected by questionnaire which contain (8) characteristics, the organizational design, strategy, process, technology, leadership, the roles, culture, and external environment). The sample contain from (76) employees;

Results points that the two organizations didn’t reach to the high level of performance, and there are significance's difference  among them.

 

 

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Crossref
Publication Date
Mon Oct 22 2018
Journal Name
Arab Science Heritage Journal
الدراسات الدراسات التاريخية الخاصة بالمرأة مراجعة تحليلية للكتابة التاريخية في العراق للمدة 1996-2008
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على الرغم من تطور الدراسات التاريخية الخاصة بالمرأة بوصفها حقل معرفي مستقل بدأ منذ نهاية الستينيات من القرن الماضي .ونجاج الكاتبات والباحثات  في العديد من بلدان الشرق الاوسط وشمال افريقيا في إعادة المرأة الى التاريخ، الا ان الكتابة التاريخية في العراق مازالت تعاني من نقص كبير في الموضوعات التي تناولت حياة النساء في الماضي. وما يزال الباحثات والباحثين ينظرون الى التاريخ على انه سردية للمعارك والحروب ويو

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Publication Date
Sat Oct 01 2016
Journal Name
Journal Of Educational And Psychological Researches
المناخ المدرسي وعلاقته بالتكيف الاجتماعي لدى تلاميذ الصف الاول الابتدائي في محافظة اربيل/ المركز
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The research aims at defining the level of the school environment and the social adjustment of the sample due to the sex and the relation among them. The two researchers have stated the school environment scale counting on the theoretical background and previous studies. As for the social adjustment scale, the researchers have used the scale of (Al-Kindy, 2001) and the school environment scale is implicated on (112) students. The schools and the students were elected in a random way. Whereas the social adjustment scale is implicated on (30) teachers in order to know their ratio of the student's adjustment. The results have appeared the satisfaction of the students on the private school environment within their school aspects (the directo

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Publication Date
Wed Mar 30 2022
Journal Name
College Of Islamic Sciences
ما خالف به الامامُ ابن السبكي الامامَ الامدي في تشنيف المسامع باب القياس انموذجا
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The idea of ​​the research at first was to find out about the rare occurrence, which is the occurrence of a violation in the same madhhab and between two Shafi’i scholars such as Al-Amadi and Ibn Al-Subki. The scholarly had some brief and then moved on to the fundamentalist violations that occurred between them in the syllabus of the hearing within the chapter on analogy exclusively. The diffuse division (within the sounding and division) of the observer and the debates, or is it confined to the beholder without the debates, Imam Al-Amadi sees the inadmissibility of analogy with the reasons, while Imam Ibn Al-Subki argues that it is permissible, and Imam Al-Amdi sees that the widespread division is an argument for the observer (Muj

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Crossref
Publication Date
Sun Jul 02 2017
Journal Name
Journal Of Educational And Psychological Researches
(دور الارشاد التربوي في محاربة المخدرات وتحقيق الامن النفسي من وجهة نظر المدرسين المرشدين )
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The research study aims to investigate the prevalence of the phenomenon of drags and the causes of this phenomenon from the teachers point  of view Two  hundred   Teachers  participated in this study Questionnaire  was used to  collect  the  data .                                 

The results emphasized the importance 0f the  educational  counseling  through  different  procedure  to prevent  drugs  abuse .   the results  also&

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Publication Date
Mon Mar 01 2010
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
أهمية تحليل بيانات النتائج المالية للعملاء: بحث تطبيقي عن التدقيق والمراجعة في سلطنة عمان
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The main function of the auditing process is to get a financial report provide information about the activities of the economic entities. The financial report's information is intended to be useful in making decisions and planning for entities future. Such information became more effective and efficient if the auditors process analytical auditing procedures, by using those financial analysis tools, which mean more detailed indicators.

The objectives of this research are to investigate auditor's use of analytical procedures in Oman and identify the main objectives for using these procedures. A questionnaire was used to gather the data for the study. A sample of 65 auditors and the response rate was 80% (52).

  &n

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