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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 May 01 2019
Journal Name
مجلة ابحاث ميسان
واقع انتاج المياه و استهلاكها في محافظات الفرات الاوسط لعام 2016
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مايزال انتاج المياه في محافظات الفرات الاوسط بشكل خاص و العراق بشكل عام نواجه تحديات كبرىالتي ادت الى تردي انتاج المياه و استهلاكها

Publication Date
Wed Dec 31 2025
Journal Name
مجلة التراث العلمي العربي
الألفون وتنوّعه في الاستعمال بين الشّيخ جلال الحنفي والدّراسات الصّوتيّة الحديثة
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لقد كان الألفون جزءاً من اللوحة الفونيميّة، وهو جزء صوتيّ لا يُغيّر المعنى، مع أنّه تغيّر صوتيّ فونيميّ، له أنواعه المتمثّلة بالهمس والجهر، والنّبر، والاختلاس، والإخفاء، والإشمام، والإقلاب، والتّماس، والقلب، وهذه الأنواع كانت مؤشّرات تنغيميّة صوتيّة نالت حظّاً وافراً لدى باحثي الأصوات وعلماء التّجويد، وكان لها شروطها ومواقعها وأثرها في المخاطِب والمخاطَب، لأنّ كلّ صوت يخرج من متكلّم ليصل إلى سامع يؤثر ب

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Publication Date
Tue Dec 01 2020
Journal Name
Al-khwarizmi Engineering Journal
Applying Trade-off Curve to Support Set-Based Design application at an Aerospace Company
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Companies compete greatly with each other today, so they need to focus on innovation to develop their products and make them competitive. Lean product development is the ideal way to develop product, foster innovation, maximize value, and reduce time. Set-Based Concurrent Engineering (SBCE) is an approved lean product improvement mechanism that builds on the creation of a number of alternative designs at the subsystem level. These designs are simultaneously improved and tested, and the weaker choices are removed gradually until the optimum solution is reached finally. SBCE implementations have been extensively performed in the automotive industry and there are a few case studies in the aerospace industry. This research describe the use o

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Publication Date
Thu Jan 01 2026
Journal Name
القبة البيضاء
دور المراكز البحثية في دعم القضايا الاجتماعية مركز دراسات المرأة أُنموذجاً
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تناول هذا البحث الدور الحيوي الذي تؤديه المراكز البحثية في دعم القضايا الاجتماعية، مع التركيز على مركز دراسات المرأة في جامعة بغداد كنموذج تطبيقي. يوضح الباحث أن هذه المراكز لا تقتصر على إنتاج المعرفة النظرية، بل تسهم بشكل مباشر في معالجة التحديات المجتمعية، من خلال تقديم رؤى تحليلية ومقترحات عملية لصناع القرار. كما ويسلط الضوء على مساهمة مركز دراسات المرأة في تعزيز المشاركة السياسية للمرأة العراقية، خاصة

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Publication Date
Sun Jan 01 2006
Journal Name
المركز العربي للدراسات والبحوث العلمية للنشر والتوزيع
القانون الجنائي في عصر الذكاء الاصطناعي :جرائم التزييف العميق تحت المجهر
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مقدمة introduction تُعد تقنيات الذكاء الاصطناعي قاطرة الثورة الصناعية الرابعة، إذ تجاوزت حدود البرمجة التقليدية إلى التعلم العميق الذي مكّن الآلات من تنفيذ مهام بشرية معقدة، مثل تحليل الصور، ومعالجة اللغات الطبيعية، وإنتاج محتوى إبداعي. فأصبحت التطبيقات تعتمد على الذكاء الاصطناعي في جميع القطاعات، من الرعاية الصحية إلى التعليم، ومن الأمن إلى الفنون. ومع ذلك، مثلما أن كل تقدم يحمل في طياته إمكانات هائلة، فإنه يج

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Publication Date
Tue Aug 25 2026
Journal Name
مجلة العصر للعلوم الانسانية والاجتماع
موقف صحيفة الاهرام من الصراع في جمهورية الكونغو الديمقراطية 1964-1965
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يتناول هذا البحث موقف ( صحيفة الاهرام) المصرية من تطورات الصراع في جمهورية الكونغو الديمقراطية خلال الفترة (1964 -1965) وهي مرحلة اتسمت باحتدام الازمات السياسية والنزاعات الداخلية في الكونغو مع زيادة التدخل الاجنبي في شؤون البلاد المتمثل بالولايات المتحدة الامريكية وبلجيكا وعلى هذا الاساس تم اختيار موضوع البحث والذي حددت بدايته بالتزامن مع عودة مويس تشومبي الى السلطة ، وما رافقها من صراعات وتمردات في الاقاليم

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Publication Date
Tue May 01 2012
Journal Name
Iraqi Journal Of Physics
Argon plasma needle source
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Non thermal argon plasma needle at atmospheric pressure was generated. The experimental set up is based on very simple and low cost electric components that generate electrical field sufficiently high at the electrodes to ionize various gases, which flow at atmospheric pressure. The high d.c power supply is 7.5kV peak to peak, the frequency of the electrical field is 28kHz, and the plasma power less than 15W. The plasma is generated using only one electrode. In the present work the voltage and current discharge waveform are measured. Also the temperature of the working Ar gas at different gas flow and distances from the plasma electrode tip was recorded

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Publication Date
Fri Jun 30 2017
Journal Name
Journal Of Engineering
Aluminium Matrix Composites Fabricated by Friction Stir Processing A Review
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      Aluminum alloys widely use in production of the automobile and the aerospace because
they have low density, attractive mechanical properties with respect to their weight, better
corrosion and wear resistance, low thermal coefficient of expansion comparison with traditional
metals and alloys. Recently, researchers have shifted from single material to composite materials
to reduce weight and cost, improve quality, and high performance in structural materials.
Friction stir processing (FSP) has been successfully researched for manufacturing of metal
matrix composites (MMCs) and functional graded materials (FGMs), find out new possibilities
to chemically change the surfaces. It is shown th

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Publication Date
Fri Jan 11 2019
Journal Name
Iraqi Journal Of Physics
Porous silicon prepared by photo electrochemical etching assisted by laser
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Porous silicon (PS) layers are prepared by anodization for
different etching current densities. The samples are then
characterized the nanocrystalline porous silicon layer by X-Ray
Diffraction (XRD), Atomic Force Microscopy (AFM), Fourier
Transform Infrared (FTIR). PS layers were formed on n-type Si
wafer. Anodized electrically with a 20, 30, 40, 50 and 60 mA/cm2
current density for fixed 10 min etching times. XRD confirms the
formation of porous silicon, the crystal size is reduced toward
nanometric scale of the face centered cubic structure, and peak
becomes a broader with increasing the current density. The AFM
investigation shows the sponge like structure of PS at the lower
current density porous begi

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Publication Date
Wed Dec 30 2020
Journal Name
Journal Of Planner And Development
Balanced Urban Development, A Strategy To Address Tension Between Different Contexts
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In their growth stages, cities become an aggregation of different urban contexts as a result of development or investment projects with other goals, which creates urban tension at several levels. Previous studies presented different approaches and methods to address specific aspects of urban stress, and thus contemporary visions and propositions varied, which required a field for research. The research, from a review of the proposals, the research problem emerged in need to study the indicators and trends of balanced urban development that address the tensions between different social, economic and urban contexts". Accordingly, the objective of the research is determined as "Building a comprehe

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