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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
Fri Jun 01 2012
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
تقويم كفاءة أداء الاستثمارات بحث تطبيقي في شركتي التأمين الوطنية والتأمين العراقية
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This study attempts to highlights on the evaluation of performance efficiency for Investments in both National & Iraqi Insurance companies for the years 2001-2010 and their importance on those companies and the economy of the country in order to find  out the investment areas and to compare between investment activity and its revenues as well as to compare performance of both companies in investment field.

The study was based on annual reports and balance sheets of both companies. In many chapters, this study dealt with theoretical and practical aspects of the investments and its revenues. Key hypothesis was based on this study, including four parts of Sub hypotheses about (statistical effective relationship between the

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Publication Date
Sat Mar 01 2008
Journal Name
Journal Of Economics And Administrative Sciences
استخدام بعض الطرائق الاحصائية والتصنيف الشجيري في التصنيف والتنبؤ بإفلاس الشركات مالياً
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تستخدم تقنيات التصنيفِ ًبصورة واسعة جدا في كثير من المجالات التطبيقية. ولاسيما في المجالات الاقتصادية والتحليلات المالية كما في عِلْمِ تحليل الزبونِ التنبؤيِpredictive customer analytics ، الذي يتضمن ذلك  الإمتلاكِ، المقايضة، إحتكار وإحراز الإئتمانِ والجباياتِ. إنّ هدفَ أيّ نموذج تصنيفِ هو أَنْ يُصنّفَ َ المشاهدات   في مجموعتين أَو أكثرِ للوصول الى التنبؤ بنتيجةً ترتبط بكُلّ مشاهدة ومثا

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Publication Date
Sat Dec 29 2018
Journal Name
Journal Of Planner And Development
اهمية تطبيق المعايير التخطيطية للفضاءات المفتوحة والخضراء ودورها في التخطيط الافضل للمدن
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Publication Date
Fri Dec 15 2023
Journal Name
Al-academy
Utilising modelling software to convert functional utensils into ceramic art.
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Contemporary art has been widely affected by technology, and ceramics production is no exception. As an ancient art that originates from clay and other humble materials found in the ground, ceramics is considered one of the most adaptable art forms. Once it is realised how flexible ceramics as a material is, it can be easily altered into endless forms and shapes. Therefore, it is vital for ceramics practitioners to find a relationship between this wonderful material and the media of contemporary art, culture and modelling software or technology in general so that they can take their deformable art pieces to a whole new level. Such a relationship is worth investigating. Thus, for the purposes of this research, several ceramic pieces were

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Publication Date
Sun Jul 06 2014
Journal Name
Journal Of Educational And Psychological Researches
الممارسات التدريسية لتدريسي أقسام كليات التربية جامعة بغداد في ضوء دوافع التعلم
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Find aimed to reveal the teaching practices of the teaching faculties of education departments of the University of Baghdad in the light of the motives of learning from the perspective of students . Researcher selected the research community in a deliberate humanitarian sections of students and faculties of education for girls and IbnRushd . Ed reached basic research sample ( 400 ) students were numbers search tool questionnaire , and included (30) paragraph . In processors statistical data , use the weighted average and the weight percentile , results have shown that it is more paragraphs which received wide acceptance from the viewpoint of students ( do not make fun of the students' answers wrong but corrects and discussed with them )

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Publication Date
Sun Jun 18 2023
Journal Name
Arab Science Heritage Journal
رعاية الايوبييـن للعلـم والعلمـاء في مصـر وبـــــلاد الشـــــــام (567-648هـ/1171-1250م)
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The Ayyub era witnessed a popular for science, knowledge and became the Ayyub state in its various regions a scientific beacon، despite their preoccupation with wars with the Crusaders now that did not discourage them from their care for science and scientists، and this scientific renaissance had many factors، foremost of which are the tendencies of the sultans and Ayyub kings to pay attention to science and its care، through their establishment of the role of science

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Publication Date
Thu Oct 01 2015
Journal Name
Journal Of Educational And Psychological Researches
القيادة التربوية في ضوء نظريتي x-yوعلاقتها بالروح المعنوية لمديري المدارس الإعدادية
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This study aimed to identify the educational leadership in the light of my theory xy and its relationship to the morale of the managers of the junior high school as the study population consisted of directors of junior high school in the city of Baghdad of six directorates education for the academic year 2013-2014 AD The number of managers (211) as director, and amounted to a sample Search of (150) director and director of the research community overall rate (71%) and represent this community fully representative sample, two tools were used in the study: the first measure of educational leadership in the light of my theory xy and the second tool to gauge morale.

Results concluded that the

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Publication Date
Fri Jan 04 2019
Journal Name
Journal Of Planner And Development
تقييم الأحوال الاقتصادية للمعيشة في مدينة الموصل: السكان والمساكن للمدة 2004-2007
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Publication Date
Fri Dec 03 2021
Journal Name
مجلة تكريت للعلوم السياسية
نظرية الاعتراف في الفكر السياسي الغربي المعاصر: أكسل هونيث ونانسي فريزر انموذجا
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يعيش المجتمع العالمي أزمات بنيوية ونسقيه عميقة واختلالات وظيفية أسهمت في تنامي مظاهر الصراع المختلفة واشتداد تفجر الأزمات الهوياتية وتزايد الامراض الاجتماعية المقضة للعيش المشترك والمربكة لمظاهر التعايش والتآلف مع لجوء إنسان العصر الحالي الى التقوقع والاحتماء والانزواء تحت هويات ضيقة ونحل صغيره في مشهد يظهر مدى تراضي شبكة العالقات الاجتماعية على أداء وظائفها وأصبح عندها الاغتراب والقلق واللاتضامن والع

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Publication Date
Tue Dec 01 2009
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
أهمية الإفصاح عن المعلومات المتعلقة بتدريب وتطوير العاملين وأثره في قرارات الاستثمار
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يكتسب موضوع تدريب وتطوير العاملين أهمية بالغة في الظروف الاقتصادية الحالية التي تسودها مفاهيم وتوجهات جديدة كعولمة الاقتصاد ورأس المال المعرفي والفكري، وحيث صارت المعارف والمهارات والقابليات التي يمتلكها العاملون محركاً أساسياً باتجاه النجاح، وعنصراً مهماً في زيادة فاعلية منشأة الأعمال، وإدامة وجودها واستمرارها.

إن العاملين المدربين بشكل جيد على عمليات المنشأة وطبيعة المواد التي تستخدمها وإنتاجه

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