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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 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
Tue Dec 30 2025
Journal Name
Iraqi Journal For Administrative Sciences
قياس الكفاءة التقنية لوحدات اتخاذ القرار باسلوب التحليل التطويقي للبيانات ( DEA) بحث ميداني في الشركة العامة للنقل البري
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this research aims it measure the technical efficiency of the branches of the General Company for Land Transport, That scattered geographically at country level, by Data Envelopment analysis (DEA) technique, as this technique relies on measuring the efficiency of a set of asymmetric Decision making units, which is one of the nonparametric mathematical methods for and application related to Linear Programming, and this is what helps the General Company for Land Transport to diagnose its branches performance by benchmarking with each other and determine the performance gap. The research found that there is variation in the level of efficiency in the company's branches

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Publication Date
Tue Jan 08 2019
Journal Name
Arab Science Heritage Journal
استخلاص عامل التلزن ( اللكتين ) من بكتريا لخلاياEnterococcus faecalis EM1 ودوره في تلزن انواع من البكتريا السالبة لملون غرام
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استخلص عامل التلزن من E. faecalis EM1 بعد تكسير بالكرات الزجاجية والترسيب بالكحول الاثيلي , واجري فحص التلزن وقياسه لمستخلص لخلايا  E. faecalis  مع انواع من البكتريا السالبة لصبغة غرام تضمنت     Escherichia coli  و Klebsiella  pneumonia  و Serratia marcescens   و Pseudomonase aeruginosa و Salmonella typhi , بينت النتائج ان اعلى نسبة تلزن للخلايا والمستخلص تكون مع بكتريا    ٍK. Pneumonia  حيث بلغ66.5 % مقارنة بالسيطرة79.5 % , واوطا قيمة للتلز

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Publication Date
Wed Apr 01 2015
Journal Name
Journal Of Educational And Psychological Researches
اثر طريقة الملاحظات الصفية باستخدام الحاسوب( كمنشطات عقلية) في التحصيل الدراسي لمادة الفيزياء لدى طالبات الصف الأول المتوسط
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The research aim to know the effect of note–taking by computer method as amentalactivators in achievement of physics subject for the first intermediate class students.

To investigate from aim of the research the research sample was chosen from the first intermediate class students in Al–mutamyzat secondary school for girls. Which belongs to the general administration for the second karkh education which randomly chosen from (9) schools for distinct female students in Baghdad. Then randomly chosen two sections form three about (80) female students at (66.667%) from total sample it’s about (120) female student in the three sections. The randomly chosen too, section (a) to represent experimental group it’s about (41) female

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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
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
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
Tue Sep 27 2022
Journal Name
Arab Science Heritage Journal
الحركة العلمية في المغرب الاسلامي من خلال كتاب معجم البلدان لياقوت الحموي ( ت 626هـ / 1229م) العلوم الشرعية انموذجا
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    The Dictionary of Countries by Yaqut al-Hamawi is one of the most important sources that researchers rely on in everything related to geography in knowing the names of places and countries, and the important historical information it contains about different cities and countries

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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
Tue Jun 13 2023
Journal Name
Journal Of Survey In Fisheries Sciences
Spectrum Analyzing X-ray Data Image (FITS) Using Ds9 Program
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n this study, data or X-ray images Fixable Image Transport System (FITS) of objects were analyzed, where energy was collected from the body by several sensors; each sensor receives energy within a specific range, and when energy was collected from all sensors, the image was formed carrying information about that body. The images can be transferred and stored easily. The images were analyzed using the DS9 program to obtain a spectrum for each object,an energy corresponding to the photons collected per second. This study analyzed images for two types of objects (globular and open clusters). The results showed that the five open star clusters contain roughly t

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