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alkej-389
Transient Behavior Analysis for Solar Energy Storage in PCM-CFM Material Using Equivalent Heat Capacity Method as Storage Model
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A paraffin wax and copper foam matrix were used as a thermal energy storage material in the double passes air solar chimney (SC) collector to get ventilation effect through daytime and after sunset. Air SC collector was installed in the south wall of an insulated test room and tested with different working angles (30o, 45o and 60o). Different SC types were used; single pass, double passes flat plate collector and double pass thermal energy storage box collector (TESB). A computational model based on the finite volume method for transient tw dimensional domains was carried out to describe the heat transfer and storage in the thermal energy storage material of collector. Also, equivalent specific heat method was employed to describe the heat storage and release in the mushy zone. Experimental results referred to an increase in thermal conductivity of paraffin wax that supported by copper foam matrix more than ten times. While the ventilation effect was still active for hours after the sun set, depending on the heat storage amount. Maximum ventilation mass flow rate with TESB collector was recorded with value equals to 36.651 kg/hr., when the overall discharge coefficient that was calculated for the system equals to 0.371. Experimental results showed that the best working angle range was 45~60o, and the highest air to the collector approaching temperature appeared to the double passes flat plate collector. Results gave greater heat storage efficiency of (47)% when the maximum solar radiation was 780 W/m2 at 12.00pm, while the energy summation through duration charge time was 18460 kJ. Computational results, depending on the equivalent heat capacity method for heat storage or release from phase change material that supported by copper foam matrix, showed the behavior of paraffin wax melting and solidification situation through periodic for charge and released heat from the solar collector. Also, these results gave agreement approaching the experimental results for the heat storage in the combined heat storage material, with standard error of 16.8%.

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Publication Date
Sat Dec 01 2012
Journal Name
Journal Of Economics And Administrative Sciences
Scheduling Critical Activities of Stochastic Projects Management
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In this paper, we consider the problem of stochastic project network when some or all activities are interrupted. An approach has been built to schedule the critical activities, by constructing some expressions based on the project lateness costs due to the interruption activities. Two simple example are presented to validate our approach.

Key words: Project Management, Project scheduling, Stochastic activity duration, Stochastic PERT.    

Introduction

   Recently, Projects planning and optimal timing, under uncertainty are extremely critical for many organizations, see [19]. Having an effective mathematical model wi

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Publication Date
Tue Dec 31 2019
Journal Name
Arab Science Heritage Journal
القنوات القنوات المحفورة في الصخر لجر المياه
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Archaeological waste in the field of irrigation and watering methods, with its agricultural experience and skills, is one of the most significant achievements of the ancients, and perhaps our study area, the province of Aurès, which is located east of Algeria, bears witness to these achievements in the light of geological, geographic and topographic data. Although the inhabitants of this territory have used many techniques for the various civilizations

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Publication Date
Sat Dec 01 2018
Journal Name
Political Sciences Journal
Globalisation and its Impact on North Korean political Regime
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Abstract Globalization dominated in the last decade of the twentieth century and the eve of the third millennium over economic,politics,psychology,culture,communications and information sciences,it's a historical phenomenon refer to many important transitions in humanitarian life.It foxes on that state has illusion its historical role in the psychologist,economic and political buldings. Globalization issue and its influence in North Korea put a spotlight on political,economic and cultural situations,the political system resists any change with many limitations on political freedoms,human rights and political multiplicity.Libralism trends and free market are so weaken when it comparing within the bad economic situation of the coun

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Publication Date
Sun Jan 13 2019
Journal Name
Arab Science Heritage Journal
الأحجار الكريمة في القرآن الكريم و التراث
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أنزل ألله تعالى كتابه العزيز على رسوله محمد(ص) هداية للناس كافة وإنقاذا لهم من الكفر والشرك والضلال ، فبين لهم فيه أمور دينهم ودنياهم وميز لهم الحرام من الحلال ، وقصَ عليهم أخبار بعض الأمم السالفة قبلهم وما نزل بهم من عقاب جزاء

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Publication Date
Mon Nov 19 2018
Journal Name
Arab Science Heritage Journal
مرويات مرويات الفكر الغيبي في مصر المملوكية
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   This research has been devoted to the study narratines of the metaphysical concepts in Egypt during the Mamluk era ( 648-923 AD/1250-1517 AH). The study consists of three sections and an  introductionwhich highlights the study at that time for its great impaction public life in Egypt.

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Publication Date
Tue Dec 28 2021
Journal Name
Arab Science Heritage Journal
التغيير الدلالي في توجيه تعدي الفعل ولزومه
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The Praise be to God, Lord of the Worlds, and prayers and peace be upon the Master of the Messengers and his pure and pure family, and may the peace and blessings be abundantly

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Publication Date
Sun Jun 30 2013
Journal Name
College Of Islamic Sciences
Abu Ubaidah's interpretative approach to the metaphor of the Qur’an
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In the name of of Allah the Merciful
        Praise be to God, and blessings and peace be upon the Messenger of God, Muhammad, and upon his family and his family and peace, and after:
 The honor of every knowledge of honor is related to it, and since the science of interpretation is related to the Book of God Almighty; it is considered one of the most noble and longest of sciences, and this science began long ago as the early ages of Islam have expanded the Islamic state, and people entered the religion of God in cohorts, and the mixture mixed In tongues, and people did not know much about the meanings of the Qur’an, so the need for authorship in this great knowledge was severe, and pe

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Publication Date
Mon Dec 01 2008
Journal Name
Political Sciences Journal
التجربة الاتحادية في دولة الامارات العربية المتحدة
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التجربة الاتحادية في دولة الامارات العربية المتحدة

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Publication Date
Wed Jun 01 2005
Journal Name
Journal Of The College Of Languages (jcl)
Dans La Maison Du Berger Et Le Mont Des Oliviers De Vigny
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Dans le romantisme et ses textes, il est important de mentionner qu'il n'existe qu'un seul thème romantique qui est l'amour, mais assez pour avoir fait du XIXème siècle, une révolution du texte romantique. L'amour consiste à la réduction de l'univers, à un seul être, puis la dilatation de ce seul être, voilà l'amour. cet amour passionnel n'est qu'un arrangement froid et réfléchi excluant d'emblée l'exaltation des sentiments. Néanmoins, cet amour passionnel peut être brutal. quant à la mort, dans le drame romantique, l'amour et la mort sont liés. Beaucoup d'histoires d'amour finissent le plus souvent par un suicide passionnel : le romantique cherche à l'atteindre par l'amour un sentiment sanctifié, et divinisé ; mais c

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Publication Date
Sun Apr 01 2012
Journal Name
Journal Of Educational And Psychological Researches
مهارات ما بعد المعرفية في الأداء التعبيري
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إن التعبير ينوء بأثقال كبيرة ، وهذه المشكلة قد تتضاعف ،لأنَّ التعبير يحتاج إلى مها ا رت " لم
تنجح المدرسة في تنميتها تنمية صحيحة " ولأنّهُ يصطدم بعوامل معوقة متعددة منها ثنائية اللغة ،
وكثافة الصفوف ، وغياب المنهج ، وٕاهمال التصحيح، ووضع المدرس لكلمة "لوحظ" من غير
ملاحظة شيء وقلة الحصص ، وضعف الربط بين فروع اللغة ، والتساهل في إعداد المدرس.
وقد كان من نتائج د ا رسة أجرتها المنظمة العربية للتربية والثقافة

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