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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 Dec 26 2019
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
أثر سياسة السجلات المحاسبية المفتوحة كأحد آليات إدارة التكلفة في تحقيق الميزة التنافسية للشركات الصناعية المساهمة العامة الأردنية
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The aim of this research is to study and test the impact of the policy of open-book accounting as one of the cost management mechanisms in achieving the competitive advantage in Jordanian industrial public companies, to achieve the objectives of the study, a field study was conducted by surveying the views of a sample of the accountants of the Jordanian industrial public companies. Hence the arithmetical Means, the Standard Deviations, the Significant Value and the Simple Linear Regression are used to test the research hypotheses and to achieve the research goals. The results of the study showed that there is a statistically significant effect of the policy of open-book accounting as one of the cost management mechanisms in achieving the

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Publication Date
Wed Dec 13 2017
Journal Name
Al-khwarizmi Engineering Journal
A Comparison Between Recursive Least-Squares (RLS) and Extended Recursive Least-Squares (E-RLS) for Tracking Multiple Fast Time Variation Rayleigh Fading Channel
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In order to select the optimal tracking of fast time variation of multipath fast time variation Rayleigh fading channel, this paper focuses on the recursive least-squares (RLS) and Extended recursive least-squares (E-RLS) algorithms and reaches the conclusion that E-RLS is more feasible according to the comparison output of the simulation program from tracking performance and mean square error over five fast time variation of Rayleigh fading channels and more than one time (send/receive) reach to 100 times to make sure from efficiency of these algorithms.

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Publication Date
Sun Jan 11 2026
Journal Name
Journal Of Babylon Center For Humanities Studies
المغول في كتاب " التاريخ الغياثي " لعبد الله بن فتح الله البغدادي الغياثي (ت بعد سنة ٩٠١ هـ / ١٤٩٥م
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Publication Date
Tue Sep 27 2022
Journal Name
Arab Science Heritage Journal
آل البيت ( عليهم السلام ) من خلال كتاب درر السمط في خبر السبط لابن الابار البلنسي الاندلسي ( ت658هـ/1260م)
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One of them one of the important books due to its containing valuable information written by the author. Information include the life of the Messenger (Peace be upon him)

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Publication Date
Tue Sep 27 2022
Journal Name
Arab Science Heritage Journal
آل البيت ( عليهم السلام ) من خلال كتاب درر السمط في خبر السبط لابن الابار البلنسي الاندلسي ( ت658هـ/1260م)
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One of them one of the important books due to its containing valuable information written by the author. Information include the life of the Messenger (Peace be upon him) before and during the mission and what happened to the messenger and his adherents and faithful companions (May Allah be pleased with them all)

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Publication Date
Wed Jan 01 2014
Journal Name
Journal Of The College Of Basic Education
اسباب الضعف الاملائي لدى طلبة كلية الادارة والاقتصاد في جامعة بغداد وطرائق معالجتها من وجهة نظر التدريسيين والطلبة
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Publication Date
Sun Jan 03 2010
Journal Name
Journal Of Educational And Psychological Researches
سياسة اعداد معلم المرحلة الابتدائية في العراق ماقبل احداث 9/4/2003 نظرة نقدية , ووضع انموذجا مقترح معاصرلها
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شغلت  قضية اعداد المعلم  اهتمامات العديد من المسؤولين في قطاع التربيه والتعليم وكذلك اولياء امور الطلبه واساتذه الجامعه , ولازالت الهم الاكبر , وذلك لاختلاف سياسه اعداد المعلم من دولة واخرى وحسب الفلسفه التربويه  والمتغيرات والتطورات السريعه التي يشهدها العالم

            وفي ضوء ماتقدم , ان المعلم هو احد عناصر العمليه التربويه في اي بلد . بعد الطالب والمنه

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Publication Date
Thu Nov 12 2020
Journal Name
Arab Science Heritage Journal
( مُختَصَرُ الإمام المَيدانيّ في عِلم التَّصريف ) للإمام أبي الفضل أحمد بن محمّد بن إبراهيم الميداني ( ت 518 هـ )
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    The aim of this research is to make a new investigation of a scientific thesis in Arabic Morphology in which an allusion occurred in relation to its real author and its title, there is alot of dropping and flaw when it was first applied due to depending on one written transcript

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Publication Date
Sun Jan 11 2026
Journal Name
Kufa Journal Physical Education Sciences
اثر تدريبات بأسلوب التدريب الدائري لبناء التحمل في تطوير بعض القدرات الحركية لأشبال لكرة القدم بأعمار (13- 15) سنة
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اهمية البحث هي مرحلة نمو وبناء اجهزة الجسم للاعبين الاشبال واعداد تدريبات بأسلوب التدريب الدائري لبناء التحمل لتطوير بعض القدرات الحركية والمهارية لدى اللاعبين الاشبال بكرة القدم , حيث لاحظت الباحثة ضعف في مستوى الاداء الحركي ارتأت اعداداً بدنيا ومهارياً منذ مرحلة البناء الأولى للاعب الفئات العمرية , واستخدم الباحث المنهج التجريبي بالاختبار القبلي والبعدي للمجموعتين التجريبية والضابطة لملائمته لطبيعة ال

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Publication Date
Sun Dec 01 2013
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
الإبلاغ المالي عن المشتقات المالية بوصفها أدوات للتحوط من المخاطر السوقية وفقاً للمعايير المحاسبية الدولية: بالتطبيق في مصرف بغـداد
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The research has  focused on accounting for marketing risks faced by banks because they are exposed to a high level of risk as a result of their great utilization of financial instruments, which may make them liable to insolvency or bankruptcy and collapse, and accordingly to major economic crises. Therefore, banks are required to manage (reduce) risks so as to prevent them. As Iraqi banks don't manage these risks according to modern methodology of using derivatives, as well as lack of both the standard accounting system for banks and the Iraqi accounting criterion (standard) No. 10 to an obvious methodology for these risks identification, classification, hedging and disclosure, the researchers was prompted to concentrate

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