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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
Mon Sep 30 2024
Journal Name
نسق
تحليل اثر برامج تدريبية في مجال تطوير المهارات الاساسية للاعبات كرة القدم للنساء
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Publication Date
Sun Jan 03 2016
Journal Name
Journal Of Educational And Psychological Researches
إنتاج المعرفة واكتسابها لدى طلبة كليات العلوم التربوية في بعض الجامعات الأردنية الرسمية
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This research attempts to propose production and acquisition of scientific knowledge among the students of educational science faculties in some universities Governmental Jordanian (Yarmouk, Jordan, Muta). In addition to sources of educational gained in some of the Governmental Jordanian universities (Yarmouk, Jordan, Muta), and to propose the necessary socio-cultural dimensions of knowledge acquisition and production, using developmental screening method, which is represented in the study design tool (questionnaire), which consisted of 4 scales, scale: The reality of the acquisition of knowledge / reality of the production of knowledge / social dimensions of knowledge acquisition and production / cultural dimensions of knowl

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Publication Date
Sun Jun 01 2008
Journal Name
Journal Of Economics And Administrative Sciences
إضواء وآراء حول واقع ومستقبل إدارة الموارد البشرية صعبة المراس في منظمات الأعمال
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The current researsh is aimed to pay attention on concept of human resources hard (Difficult) to manage. Such style of human resourcses has emerged to form anew challenge for busniess organizations.

Management such human resources entails first determing incentives of their behaviour models. Analyzing these models will be important to strategical management of them from work.

In nutshell, this researsh try to recommendation of contemporary literature about future of difficult (hard) human resources management.

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Publication Date
Sun Oct 01 2017
Journal Name
Journal Of Educational And Psychological Researches
أثر برنامج التعبئة النفسية في مواجهة أحداث الحياة الضاغطة لدى طلاب المرحلة الاعدادية
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The Stressful Life Events consider one of the important thing in humans life in different period of life even school period,   where it is deal with vital period of life which is the youth period that represent the hope and precious resources that nation depend on it in building her civilization, structure anddevelopment  ,they are part from the present and whole future .As the great effect of stressful life event on humans , increase the need to put a program about psyching-up which consider one of the modren and effective programs.The aim of current search:1.   Measure the level of stressful events at the junior high school  studen

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Publication Date
Sat Dec 29 2018
Journal Name
Journal Of Planner And Development
اثر العامل الديني في تخطيط المدينة العربية والعمارة الاسلامية مدينة النجف الاشرف أنموذجاً
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Publication Date
Mon Jan 01 2018
Journal Name
Journal Of The College Of Languages (jcl)
הסיפור העברי באמריקה ברבע השני של המאה ה-20 הסופר שמעון הלקין כדוגמה
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                                      הסיכום

          הסיפורת העברית באמריקה, הייתה קשורה בסביבה מסויימה. גם כן היא קשורה בנושאים מסויימים, ורובם היו מדברים על חיי היהודים באמריקה.

            דמותו של שמעון הלקין קבועה בנפשם של המבקרים כזו של משורר בעי

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Publication Date
Sat Jun 30 2007
Journal Name
Al-kindy College Medical Journal
Arthrogrypotic Club Foot
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Background: Arthrogryposis Multiplex congenita is a
rare disorder, characterized by multiple joint deformities
i.e. multiple congenital contractures, with shapelessly
cylindrical limbs and absent skin creases.
Club foot can be the only obvious deformity of this
widespread disorder.
Objective: To assess the most frequent recurrent
deformity after extensive soft-tissue release operations for
arthrogrypotic club foot and its appropriate treatment
regarding combined tendon transfer and bony operations.
Methods: A retrospective study of 14 patients with
arthrogrypotic club foot (28 feet), had been operated on by
multiple soft tissue and bony operations and followed in a
period between January (1993) till

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Publication Date
Tue Dec 05 2023
Journal Name
Baghdad Science Journal
Indoor/Outdoor Deep Learning Based Image Classification for Object Recognition Applications
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With the rapid development of smart devices, people's lives have become easier, especially for visually disabled or special-needs people. The new achievements in the fields of machine learning and deep learning let people identify and recognise the surrounding environment. In this study, the efficiency and high performance of deep learning architecture are used to build an image classification system in both indoor and outdoor environments. The proposed methodology starts with collecting two datasets (indoor and outdoor) from different separate datasets. In the second step, the collected dataset is split into training, validation, and test sets. The pre-trained GoogleNet and MobileNet-V2 models are trained using the indoor and outdoor se

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Publication Date
Sun Jun 12 2011
Journal Name
Baghdad Science Journal
Parabola Dish and Cassegrain Concentrators to Improve Solar Cell Conversion Efficiency
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New designs of solar using ray tracing program, have been presented for improved the performance and the out put power of the silicon solar cell, as well as reducing the cost of system working by solar energy. Two dimensional solar concentrator (Fresnel lenses) and three dimensional concentrators (parabola dish and cassegrain) were used as concentrator for photovoltaic applications (CPV). The results show that the performance efficiency and out power for crystalline silicon solar cells are improved.

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Crossref
Publication Date
Sun Jun 12 2011
Journal Name
Baghdad Science Journal
Hybrid(Luminescent and Fresnel ) Concentrators to Improve Solar Panel Conversion Efficiency
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The spectral response of the Si solar cell does not coincidence with the sun irradiance spectrum, so the efficiency of the Si solar cell is not high. To improve the Si solar cell one try to make use of most region of the sun spectrum by using dyes which absorb un useful wavelengths and radiate at useful region of spectrum (by stock shift). Fluorescence's dye is used as luminescent concentrator to increase the efficiency of the solar cell. The results show that the performance efficiency and out power for crystalline silicon solar cells are improved.

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