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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
Sat Jun 01 2013
Journal Name
Journal Of Economics And Administrative Sciences
Internal control – Internal check
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Abstract

All the economic  units whether productive or service units , strive to achieve specific objectives , their presence and continuity depend on them and the quality of the performance and service present to the society . This units to be able to achieve their objectives , must own basic assets to perform the activities , and apply laws , systems , and instructions , in addition to legal , managerial , and financial authorities . So this units to endeavor maintain this assets , in addition to sound application of laws ,systems . and procedures to enhance their performance . For this purpose arise the role of internal control and internal check in maintenance of assets and sound application of&n

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Publication Date
Sat Jan 01 2005
Journal Name
Journal Of The College Of Languages (jcl)
تحليل الأخطاء الصوتية في بعض كتب اللغة الروسية الدراسية
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تحليل الأخطاء الصوتية في بعض كتب اللغة الروسية الدراسية

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Publication Date
Sun Jan 02 2005
Journal Name
Political Sciences Journal
عرض اطروحة (الحركات الاسلامية في ظل الوضع الدولي الجديد)
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الحركات الاسلامية في ظل الوضع الدولي الجديد

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Publication Date
Thu Nov 08 2018
Journal Name
Iraqi National Journal Of Nursing Specialties
المشكالت الصحية المرافقة لالستخدام الخاطئ للحاسوب في مدينة بغداد
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The Research aimed for identification the significant of health problems that occurrences through
misused of computer for those whom attaches with more than two hours daily and to identification the
nature of demographical characteristics variables and that related variables with using computer. Also to
know the level of user’s knowledge for some attaché’s equipment's and finally creating a new suggested
measurement scale for studying health problems that were occurred through misused of computer.
Creating questionnaire includes several domains (Social problems – family environment, Social problems –
external environment, some health problems attaches with related equipment's, psychological problems,
and hea

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Publication Date
Wed Nov 28 2018
Journal Name
Arab Science Heritage Journal
بابل بابل في العصر الشبيه بالكتابي وعصر فجر السلالات
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This study deals with the region of the Babylon governorate in Iraq during the Proto-Literate and Early Dynastic periods. It is the region of the well- known ancient capital Babylon. The earlier period includes Late Uruk, Jamdat nasr, and the first epoch of the Early Dynastic period. The latter includes the second and third epochs of the Early Dynastic period. The both periods had lasted more than one thousand years (3500-2334 BC

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Publication Date
Sun Apr 01 2012
Journal Name
Journal Of Educational And Psychological Researches
حقوق الطفل في ظل الأزمات المجتمعية /الطفل العراقي انموذجا
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Rights of child in the community crisis Iraqi child model The study aimed to identify the types of violation against children in the Iraqi crisis as well as to develop community coping mechanisms to these violations and promote the rights of the child health psychological , social and legal . the first chapter discusses the research problem and its importance and purpose of the research problem and its importance and purpose of the research and the most important terms in the A- Rights of the child ,B- crisis , chapter 2 rights of the child ensure the historical roots , of children’s rights in the holy quran and the sunnah, and legal rights through the twentieth century and the beginnings of century xx, the se through the twentieth cen

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Publication Date
Thu Dec 13 2018
Journal Name
Arab Science Heritage Journal
ال أل العاقولي ودورهم العلمي في الحضارة العربية الإسلامية
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The research includes a bout IL- IQulle , and their role in scientific of the Islamic – Arabic civilization , for Dr. Khlood M.Namma the proff in the collage of education for woman , Baghdad university , History department

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Publication Date
Sun Jan 01 2012
Journal Name
Journal Of The College Of Languages (jcl)
הריאליזם ביצירותיו של אהרן מגד "דוגמאות נבחרות מיצירותיו"
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הקדמה

             הריאליזם הספרותי במשמעו הכללי מצייג אשר כל מה מציינת בה הספרות מציורים מדוייקים לסביבה ולכן אדם. ויש להתחשב בפרטים המשותפים לחיים היומיומית.

             האסכולה הריאליזטית מצטיינת בזיאנרים אין זוכים בם איזו אסכולה ספרותית אחרת. האסכולה הזאת הופיעה בספרות העברית החדשה כתוצאה להשפעתה של הספרות העברית בס

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Publication Date
Mon Jan 01 2018
Journal Name
Journal Of The College Of Languages (jcl)
LA METÁFORA, LA METONIMIA Y OTROS FENÓMENOS RETÓRICOS EN LENGUA ÁRABE Y ESPAÑOLA
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Resumen:

En este artículo se indaga sobre fenómenos como la metáfora, la metonimia, la polisemia, y la homonimia en las lenguas árabe y española, según la teoría cognitiva, basada en el pensamiento y la práctica lingüística. Esta teoría intenta investigar la relación entre el lenguaje humano, la mente y la experiencia. En realidad, los fenómenos que estudiaremos crean ambigüedad léxica y sintáctica tanto en árabe como en español. Además, dichos conceptos tienen sus propias características, especificaciones y formas en cada lengua.
Abstract:

This article studies phenomena such as metaphor, metonymy, polysemy, homonymy in Arabic and Spanish, according to cognitive theory, based on linguistic thought a

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Publication Date
Mon Nov 19 2018
Journal Name
Arab Science Heritage Journal
تعمير تعمير الأرض وأهمية الغرس في ضوء السنة النبوية
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Islam is a religion that God wanted to be a platform emerges from human steps in various walks of devotional and economic life, etc, so it went Islam, guids human beings being as successor of God on earth.

 The result that the worship of man for the Lord, which is one of the reconstruction of the land that is the secret of the sustainability of human life on the ground, often urged the Sunnah on the reconstruction of the earth and the importance of planting them and paired the reconstruction work that obtained by the human reward which would Allah his home in the Hereafter, There construction of the earth does not involve just planting them; it takes many forms Maintaining them and not marring the form of reconstruction and

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