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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
Tue Jan 29 2019
Journal Name
Arab Science Heritage Journal
المنهج التجريبي والمنهج الرياضي في فلسفة الكندي
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الكندي هو ابو يوسف يعقوب بن اسحاق بن الصباح . كما هو عند ابن جلجل (1) بن عمران بن اسماعيل بن محمد بن الأشعث بن قيس الكندي . كما يضيف ابن النديم(2) كان أبوه اسحق بن الصباح أميرا ً على الكوفة للمهدي والرشيد . على ما يقرره ابن نباته المصري(3) ، كان جده الأشعت بن قيس من أصحاب النبي الكريم وكان قبل ذلك ملكا ً على جميع(كندة)

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Publication Date
Sun Jun 18 2023
Journal Name
Arab Science Heritage Journal
أهل الذمة وأثرهم العلمي في العصر العباسي
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Non-Muslim scholars, who are Jews, Christians, Sabians and Magi, excelled in various pure scientific and human sciences, being the owners of civilizational inheritances. On the rest of the sciences in which non-Muslims excelled, namely mathematics, chemistry, astronomy, astrology, philosophy, history, and the Arabic language.

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Publication Date
Sun Sep 03 2023
Journal Name
مجلة درااست دولية
بناء الدولة في الفكر السياسي لجون راولز
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تعد مسالة بناء الدولة احدة المواضيع المهمة في حقل الدراسات السياسية والتي تعكس مظهراً متعدد الابعاد لمبدأ الثقة المنشود بين الحاكم والمحكوم، فمنذ أمد طويل تحاول الدول تحقيق تنميتها السياسية والبحث عن مقومات ترشيد سياسي لقدراتها المؤسساتية والوظيفية بهدف تعزيز اسس التكامل والاندماج بين المجتمع السياسي والمجتمع المدني. عليه انطلق جون راولز في مفهومه لبناء الدولة المعاصرة من بناء المجتمع العادل، فالعدالة ه

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Publication Date
Fri Jan 01 2016
Journal Name
Journal Of The College Of Languages (jcl)
Étude des aspects de la peur Dans « La Peste » d'Albert Camus
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Resumé

La Peste, paru en 1947 et qui reçoit le prix des critiques acquiert a Camus  une notoriété universelle, il reçoit en 1957 le prix Nobel pour une œuvre qui, selon les termes de l’Académie suédoise : « met en lumière les problèmes se posant de nos jours à la conscience des hommes ». A Oran où il n’arrive jamais rien, quelque chose va arriver. On découvre un rat mort, couvert de sang. Deux jours après on en trouve des centaines, puis des milliers. Deux semaines plus tard, un homme meurt d’une maladie, décrite avec précision, mais sans recherche de l’horreur. Après cet événement, on signale une dizaine, puis une vingtaine de cas de fiè

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Publication Date
Thu Sep 12 2019
Journal Name
Al-kindy College Medical Journal
A Case Report -Bilateral Giant Achilles Tendon Xanthomas Resection with a Tendon transverse Technique
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Background : Xanthomatosis is a disease in which large tendon tumors can occur, especially in the Achilles tendon. This disease is a rare interesting orthopaedic condition.

Case Report:A case of a twenty eight year old girl patient with giant bilateral Achilles tendon xanthomas in which both tumors were resected.

There was no ulceration on the both sides. The patient was treated by total resection of the lesion and reconstruction using tendon transfer of the Peroneus brevis and Flexor hallusis longus. Postoperative treatment consisted of six weeks lower leg cast immobilization followed by partial weight bearing. After 4 months the patient was able to walk pain free without any difficultie

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Publication Date
Mon Jun 03 2019
Journal Name
Al-kindy College Medical Journal
A Case Report -Bilateral Giant Achilles Tendon Xanthomas Resection with a Tendon transverse Technique
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Background : Xanthomatosis is a disease in which large tendon tumors can occur, especially in the Achilles tendon. This disease is a rare interesting orthopaedic condition. Case Report:A case of a twenty eight year old girl patient with giant bilateral Achilles tendon xanthomas in which both tumors were resected. There was no ulceration on the both sides. The patient was treated by total resection of the lesion and reconstruction using tendon transfer of the Peroneus brevis and Flexor hallusis longus. Postoperative treatment consisted of six weeks lower leg cast immobilization followed by partial weight bearing. After 4 months the patient was able to walk pain free without any difficulties. It has been suggested that total resection with au

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Publication Date
Sun Apr 23 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Electron Transfer At Metal/Molecule Interface
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   Theoretically description of the electron transfer of the electron transfer of met/mol has been investigated in this work according to the quantum theory. By using a model that is derived depending on the first order perturbation theory, the rate constant at met/mol interface can be calculated with the calculated reorganization energy. The reorganization energy that is evaluated according to the outer sphere model is based on the electstatistics potential of the molecular donor and acceptor. The molecular parameters introduced in this model are the molecular weight, mass, density, and radius of molecule have been evaluated according to the apparent molar volume using spherical approach.       Th

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Publication Date
Sun Apr 23 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Charge Transport At Liquid/Liquid Interface
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 Charge  transfer (CT) at  liquid/liquid  interfaces are described  theoretically depending on  the quantum theory .A model that derived used to calculate the rate constant  of transport at liquid/liquid  interfaces. The calculation of the rate constant of  charge  transfer depends on  the calculation of the reorganization energy, driving force ,and the coupling coefficient . Large reorganization energies  and large rate constant  for charge transfer ,indicate that the transitions involve more energy to happen . The system have large 𝐸0 (𝑒𝑉) refers that  type  of  liquid  is more reactive media than other liquid types with same d

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Publication Date
Thu Dec 26 2019
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
العلاقة بين النظام المحاسبي الحكومي التقليدي في العراق والنظام الإلكتروني بين النظرية والتطبيق: (بحث تطبيقي في جامعة ديالى 2018)
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  That the government sector takes a big place in the countries and represents a significant role in the face of challenges and adaptation to the important and necessary changes that occur today, including the use of electronic. The electronic computer is a requirement of modern technology in various fields of science, including accounting, Because it derives its entity and content from the spirit of society and its mentality in all its branches, especially the subject of the research system of government accounting Because of its impact on the planning and financial implementation, especially in the preparation and implementation of the State budget, along with expenditure and revenue. Addressing tells us that the first of the sear

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Publication Date
Mon Oct 01 2007
Journal Name
Journal Of Educational And Psychological Researches
اسباب السرقة لدى تلاميذ المرحلة الابتدائية من وجهة نظر المعلمين والمعلمات في المدارس الابتدائية في مدينة المكلا بمحافظة حضرموت
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يهدف البحث الحالي التعرف على اسباب السرقة لدى تلاميذ المرحلة الابتدائية كما يراها معلموهم ومعلماتهم ، وعن الاساليب المتبعة في معالجة ظاهرة السرقة من قبلهم ، ولقد شملت عينة البحث على ( 200 ) فرداً من معلمي ومعلمات تلاميذ المرحلة الابتدائية في مدينة المكلا للعام الدراسي ( 2004 ـ 2005 ) ، وقد استخدمت الباحثة استبياناً أعدته كأداة للوصول الى اهداف البحث بعد ان تم التأكد من صدقه وثباته ، استخدمت الباحثة معادلة ارتب

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