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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
Wed Dec 18 2019
Journal Name
Baghdad Science Journal
Structural and Optical Properties for Nanostructure (Ag2O/Si & Psi) Films for Photodetector Applications
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Ag2O (Silver Oxide) is an important p-type (in chasm to most oxides which were n-type), with a high conductivity semiconductor. From the optical absorbance data, the energy gap value of the Ag2O thin films was 1.93 eV, where this value substantially depends on the production method, vacuum evaporation of silver, and optical properties of Ag2O thin films are also affected by the precipitation conditions. The n-type and p-type silicon substrates were used  with porous silicon wafers to precipitate  ±125 nm, as thick Ag2O thin film by thermal evaporation techniques in vacuum and via rapid thermal oxidation of 400oC and oxidation time 95 s, then characterized by measurement of

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Publication Date
Mon Dec 30 2019
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Biodiesel production from used vegetable oil (sunflower cooking oil) using eggshell as bio catalyst
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Bio-diesel is an attractive fuel fordiesel engines. The feedstock for bio-diesel production is usually vegetable oil, waste cooking oil, or animal fats. This work provides an overview concerning bio-diesel production. Also, this work focuses on the commercial production of biodiesel. The objective is to study the influence of these parameters on the yield of produced. The biodiesel production affecting by many parameters such s alcohol ratio (5%, 10%,15 %, 20%,25%,30%35% vol.), catalyst loading (5,10,15,20,25) g,temperature (45,50,55,60,65,70,75)°C,reaction time (0-6) h, mixing rate (400-1000) rpm. the maximum bio-diesel production yield (95%) was obtained using 20% methanol ratio and 15g biocatalyst at 60°C.

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Publication Date
Wed Jul 14 2021
Journal Name
The Open Civil Engineering Journal
Producing Sustainable Concrete using Nano Recycled Glass
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Background:

Many tools and techniques have been recently adopted to develop construction materials that are less harmful and friendlier to the environment. New products can be achieved through the recycling of waste material. Thus, this study aims to use recycled glass bottles as sustainable materials.

Objective:

Our challenge is to use nano glass powder by the addition or replacement of the weight of the cement for producing concrete with enhanced strength.

Methods:

A nano recycled glass p

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Publication Date
Tue Dec 31 2019
Journal Name
Arab Science Heritage Journal
جهود جُهُودُ عُلَمَاءِ العِرَاقِ في تَدْوِينِ الف هَ ا رِسِ والكَ ش ا فَاتِ والمَ جَ ل تِ المعْ ن يةِ بال ت راثِ
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The scholars of Iraq in the modern and contemporary era have been interested in the definition of tremendous knowledge treasures left by the successive Iraqi civilizations on Mesopotamia and around the cities, through the census and extrapolation of manuscript heritage and even printed, they compiled indexes,evidence

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Publication Date
Sun Jan 13 2019
Journal Name
Arab Science Heritage Journal
استخلاص عامل التلزن ( اللكتين ) من بكتريا لخلايا Enterococcus faecalis EM1 وتأثير العوامل البيئية المختلفة عليه ودوره في تلزن أنواع من البكتريا السالبة لملون غرام
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استخلص عامل التلزن من E. faecalis EM1 بعد تكسير الخلايا بعدة طرق واختيار الطريقة التي تعطي اعلى قيمة تلزن والترسيب بالكحول الاثيلي , واجري فحص التلزن وقياسه للمستخلص  مع انواع من البكتريا السالبة لملون غرام تضمنت     Escherichia coli  و Klebsiella  pneumoniae  و Serratia

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Publication Date
Thu Mar 18 2010
Journal Name
Spe Projects, Facilities & Construction
Correlating Optimum Stage Pressure for Sequential Separator Systems
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Summary<p>A study to find the optimum separators pressures of separation stations has been performed. Stage separation of oil and gas is accomplished with a series of separators operating at sequentially reduced pressures. Liquid is discharged from a higher-pressure separator into the lower-pressure separator. The set of working separator pressures that yields maximum recovery of liquid hydrocarbon from the well fluid is the optimum set of pressures, which is the target of this work.</p><p>A computer model is used to find the optimum separator pressures. The model employs the Peng-Robinson equation of state (Peng and Robinson 1976) for volatile oil. The application of t</p> ... Show More
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Publication Date
Wed Dec 28 2022
Journal Name
مجلة التربية الرياضية
إدارة درس التربية الرياضية لدى الطالب المطبق وفقا المهارات التدريسية من وجهة ً الهم نظر اعضاء هيأة التدريس في كلية التربية البدنية وعلوم الرياضة جامعة بغداد
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Publication Date
Thu Jul 02 2009
Journal Name
Journal Of Educational And Psychological Researches
الإدراك الحسي الحركي لدى الطلبة المتفوقين والمتأخرين دراسيا في المدارس الإعدادية (بحث مستل من رسالة ماجستير بنفس العنوان / جامعة بغداد) كلية التربية للبنات 2009 م
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مشكلة البحث   The Problem of the Research

 

          يعّد التحصيل الدراسي للطلبة عموما من أهم أركان النشاط العقلي في المجال التربوي، فلا تكاد تخلو منه أيه مدرسة، أبتداءً من المدارس الابتدائية وقد تسبقها رياض الأطفال، إلى المدرسة الإعدادية والجامعية ، وقد تمتد إلى مراحل متقدمة في العمر، فكان الطالب وما يزال هو محور العملية ال

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Publication Date
Sat Apr 01 2017
Journal Name
مجلة العلوم الاحصائية
نمذجة السلاسل الزمنية التي تنتجها اجهزة الاحصاء الدولية وانتاج قيم تنبؤية لمتخذ القرار حالة دراسية : التنبؤ بالمساحة المزروعة لمحصول الذرة الصفراء في العراق للفترة (2015-2020
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تنفذ أجهزة اإلحصاء الدولية ومنها الجهاز المركزي لإلحصاء في العراقإحدى أجهزة وزارة التخطيط، تقوم بإجراء مسوح سنوية ودورية لإنتاج مؤشرات تقييم وتقويم أنشطة القطاعات الاقتصادية المختلفة. يتيح هذا الكم الهائل من البيانات بشكل سلسل زمني لهذه الأجهزة إنتاج مؤشرات جديدة، بما في ذلك القيم التنبؤية لمؤشرات رئيسية تستخدم في إعداد الخطط طويلة وقصيرة المدى. في عام 2015، قامت مديرية الإحصاء الزراعي في الجهاز المركزي للإ

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Publication Date
Sun Apr 10 2022
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
أثر خصائص لجنة التدقيق في الإفصاح عن رأس المال الفكري: أدلة من فسطين: The Impact of Audit committee characteristics on Intellectual capital disclosure : Empirical evidence from Palestine
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The study aimed to examine the impact of audit committee characteristics on the practices of intellectual capital disclosure in the annual reports of Bank and Insurance companies listed on Palestine Exchange, through performing content analysis of the annual reports for the study sample which totaled thirteen companies, including six banks and seven insurance companies. To achieve the study objectives, the study employed a content analysis approach in order to analyze the content of the intellectual capital disclosure practice, in addition, the study used cross-sectional with longitudinal data for time series for a period of time between 2014-2019. The empirical results indicated that financial expertise and the number of meeting

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