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alkej-265
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
Mon Jul 01 2013
Journal Name
دراسات دولية
قراءة في المذهب العسكري الروسي بين الماضي والحاضر
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إن أهميـة بحثنـا تتضـح مـن خـلال التطـرق إلى دراسـة المـذهب العسـكري في حقبـة الاتحـاد السـوفيتي السـابق وإبـراز الجوانـب الرئيسـة المتعلقـة بفلسـفة المـذهب العسـكري السـوفيتي ومضـامينه الاستراتيجية مــن جانــب، وفلســفة المــذهب العســكري الروســي لمرحلــة مــا بعــد الحــرب البــاردة والتغـيرات المهمـة الـتي طـرأت عليـه، ممـا أفـرز لنـا بطبيعـة الحـال مضـامين مـذهب عسـكري روسـي جديــد قــد يتقــا

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Publication Date
Tue Nov 13 2018
Journal Name
Arab Science Heritage Journal
اثر أثر العقيدة في ترسيخ التمكين عند المسلمين
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That is feared we frequent urgent calls from Islamic scholars and leaders of the Muslim faithful to their religion and nation to a culturally، economically، politically and militarily Muslim communities، in response to the call of the divine stones in the sit-rope of God and taking the greatest causes of strength and stamina، pride and empowerment

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Publication Date
Mon Jul 22 2019
Journal Name
Arab Science Heritage Journal
سة الشخصيات في رواية القضية تنتصر"لبنت الهدى
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قسّم الباحث الشخصيات في هذ ا البحث إلى أقسام: اإيجابية والسلبية
والسطحية...ثم تطرقا إل خصوصياتها النفسيّة وبينا مقصود الكاتبة، وتطرّقا إلی الغزو
الثقافي الغربي ،

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Publication Date
Tue Oct 23 2018
Journal Name
Journal Of Planner And Development
اساسيات (التنظيم المكاني –الاجتماعي ) في تخطيط المجمعات السكنية
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Publication Date
Sun Dec 23 2018
Journal Name
Arab Science Heritage Journal
دور دور الخلافة العباسية في تقوية النشاط التجاري
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The role of the Abbasid Caliphate in strengthening the business with the Indian subcontinent and development. Came upon Baghdad and the shift of succession to Iraq in the forefront of efforts made by the Abbasids to revive the trade with Eastern countries, given that the commercial was targeted among other factors,'s location in Iraq amid the ancient world among the countries of Turk

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Publication Date
Mon Jan 23 2023
Journal Name
Arab Science Heritage Journal
التجارة في البحرين من خلال كتب الرحالة والبلدانيين
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Economic life in any of the countries depends mainly on economic activity due to its great role in meeting the needs and expenditures of the state . therefore ، Bahrain played a major role in commercial exchange operation ،  whether at home or abroad . whatever the matter

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Publication Date
Sun Oct 01 2006
Journal Name
مجلة كلية التربية البدينة و علوم الرياضة للبنات
انخفاض مستوى العروض الرياضية في المهرجانات الرياضية المدرسية
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Publication Date
Wed Oct 04 2023
Journal Name
Arab Science Heritage Journal
مرجعية الموروث الشعري في شعر ابي إسحاق الغزي
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Literary heritage and its employment in poetry has received the attention of poets, and they have employed it in their literary texts, as this employment is one of the oldest phenomena in Arabic literature, that the inspiration of this heritage in texts through the overlap of their texts with previous texts, and no poet neglected the importance of this employment.  The ancient critics determined that the poet’s special culture is represented in the necessity of taking from the ancients, and this taking is the reference from which the poet draws his material and idea, as well as to clarify the meaning and its significance

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Publication Date
Tue Nov 06 2018
Journal Name
Arab Science Heritage Journal
الفكر الفكر العمراني عند اليعقوبي في كتابه البلدان
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وفي الحقيقة وأنا أكتب عن الفكر العمراني عند اليعقوبي وقفت وقفات طويلة أردت منها أن أحدد المجال الذي أبدع فيه اليعقوبي لكي أوسم موضوع بحثي، كأن أقول عنه الجغرافي أو مهندس أو رحالة أو أديب، لكني وجدته جغرافياً طبيعياً وبشرياً ومهندس بناءً عارفاً بمواد البناء وهندسة البناء وهندسة المساحة والطرق والجسور والهندسة المعمارية، لذا وجدته موسوعة لكل ما كان في عصره من العلوم، فضلاً عن كونه مؤرخاً، له مؤلفة المشهور ((

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Publication Date
Wed Jan 07 2009
Journal Name
Political Sciences Journal
السياسة في الفلسفة الاسلامية : الفكر السياسي عند الفارابي
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السياسة في الفلسفة الاسلامية : الفكر السياسي عند الفارابي

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