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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
Thu Apr 04 2019
Journal Name
مجلة كلية التربية
جدلية الحركة والسكون والحرف والمقطع رصد وتأصيل لمفهوم المقطع في إيقاع الشعر العربي
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Publication Date
Mon Jan 07 2019
Journal Name
Arab Science Heritage Journal
دور دور العرب والمسلمون في نشر محاصيل الخضر والفواكه التي إلى دول العالم
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     شهد العصر الذهبي للإسلام تحول أساسي في مجال الزراعة عرف باسم "الثورة الزراعية الإسلامية" أو" الثورة الخضراء"  أو "الثورة الزراعية العربية" ، وقد أتاح الوضع الاقتصادي العالمي الذي أسسه التجار المسلمون في جميع أنحاء العالم القديم ، نشر العديد من النباتات والتقنيات الزراعية بين أجزاء مختلفة من العالم ا

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Publication Date
Mon Feb 04 2019
Journal Name
Journal Of The College Of Education For Women
اثر استخدام دورة التعلم في تحصیل طالبات مرحلة الرابع العام للمعلومات الفیزیائیة واستبقائھا
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This research aims to reveal the impact of applying a teaching course in
gaining and preserving information by female students comparing with the
traditional method, through testing the two following hypotheses:
1. There is no difference with statistical significance at the level of
significance (0.05) between the average grades achieved by the
experimental group of female students taught using a teaching course,
and the control group of female students taught using the traditional
method.
2. There is no difference with statistical significance at the level of
significance (0.05) between the average grades achieved by the
experimental group of female students taught using a teaching course,
and the contro

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Publication Date
Fri Feb 08 2019
Journal Name
Journal Of The College Of Education For Women
تجلیات اللغة الایحائیة في دعاء الصباح للامام علي بن ابي طالب (علیھ السلام)
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The literary aspect of any text reveals when it used The inspiration language
which reveals the creative aspect of language for the creator (writer) he in turn
will seek for the best choice from these aspects then, he will distribute them due
to their intention, and according to the their context
Thus, propagandistic text contains many moral features which the language
accord to thus , we found that the morning (dua al asbah)is full of creative
literary manifestations through many abstentions which happened in different
structures that contain the text, especially in structure of metaphor, and contrast.
we found many outstanding gaps and abstentions in these are given life, matter
that gives the text the most l

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Publication Date
Fri Sep 01 2006
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
تقييم الأساليب و المؤشرات المالية في تحديد كفاءة وفاعلية وإصلاح أنظمة المؤسسات المصرفية
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تلعب المؤسسات المصرفية دورا مهما و رئيسيا في اقتصاد أي بلد من خلال قيامها في تعبئة مدخرات المجتمع و من ثم توجيهها نحو الفرص الاستثمارية المختلفة التي تزيد من معدلات النمو الاقتصادي و التوظيف الكامل للموارد وكما هو معروف  فأن الجهاز المصرفي يؤدي مهام اقتصادية تخضع للتغيرات المستمرة و على الرغم من ان وظائفه التقليدية لازالت على حالها ألا وهي قبول الودائع و منح القروض و التسهيلات الائتمانية نجد أن الوسائل و

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Publication Date
Thu Dec 22 2022
Journal Name
مجلة الزرقاء للبحوث والدراسات
صياغة استراتيجية الامن القومي للدولة في ضوء ادراك التهديدات المتغيرة : الاستراتيجية الروسية انموذجا
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Publication Date
Sun Jul 02 2017
Journal Name
Journal Of Educational And Psychological Researches
اثـر انمــوذج 4EX2 في تعديل الفهم الخاطئ للمفاهيم الكيميائية لطلاب الصف الثالث المتوسط
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The Current research aims to identify ( The effects of 4EX2 Model in Misconception of Chemical concepts and Higher Order Thinking for the Students of the Third grade average ) , To verify the objective of this research , the researchers added nul hypothesis following : There is no difference is statistically significant at the level of ( 0.05 ) between the average scores of students who studied 4EX2 Model and the average students who studied by using the Misconception of Chemical concepts and Higher Order Thinking test. The research was conducted on a sample of the average Third grade students in a Baghdad secretary for boys affiliated to the General Directorate for Educational in Baghdad Al – karkh 3 and for academic year ( 2015 – 2

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Publication Date
Tue Dec 22 2020
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
قياس مخاطر الائتمان المصرفي ودورها في تحقيق الافصاح المحاسبي بالمصارف العراقية: أطار مقترح
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Bank credit  function plays an important role in realizing the targets of commercial banks , so that the credit dominate the most of assets for these banks , also the credit contribute by bigger share of operational income for these banks .Bank credit faces

high challenge that it is bank credit risks which hinder realizing goals of bank credit . the researcher discover that in spite of the international accounting standards assured that it  is necessary to disclose about risks related assets, which include bank credit, and also disclosure about fund which specified to face probable loss for this credit , but the recent disclosure about bank credit risks and its provision indicate that it faces sever defect which hinder

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Publication Date
Fri Jan 21 2022
Journal Name
مجلة كلية الرافدين للعلوم الجامعة
تحليل وقياس الاستدامة المالية لصندوق التقاعد والضمان الاجتماعي في العراق للمدة 2004-2018
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يعد تحليل السلاسل الزمنية من المواضـيع الهامة في تفسير الظـواهر التي تحدث خلال فترة زمنية معينة. ان الهدف من هذا لتحليل هو الحصـول على وصف وبنـاء أنموذج مناسب من اجل اعطاء صورة مستقبلية واضحة للسلاسل الزمنية المدروسة وان السلاسل الزمنية اهم الادوات المستخدمة في بناء وتقدير والتنبؤ بالظواهر المختلفة وان الاستدامة المالية هي الحالة التي تكون فيها الدولة قادرة على الوفاء بالتزاماتها الحالية والمستقبلية من غي

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Publication Date
Tue Mar 01 2011
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
دور الاعتماد المزدوج للكلفة التاريخية والقيمة العادلة في تحقيق ملائمة وموثوقية البيانات المالية
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Performance measurement is considered one of the most important issues in

Measuring performance effectiveness in the educational institutions by maintaining balance among quantity measurable factors. They can be financial or non‐financial factors. Consequently they reflect decisive factors in the success of educational institutions and determining suitable standards and dimensions for their activities and giving it proportional importance. Adopting the idea of Balanced Score Card as one of the modern administrative techniques and methods by educational institutions assists in the development of administrative work, adjusting the performance in addition to achieving comprehensive standard and development of educational universit

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