A paraffin wax and copper foam matrix were used as a thermal energy storage material in the double passes air solar chimney (SC) collector to get ventilation effect through daytime and after sunset. Air SC collector was installed in the south wall of an insulated test room and tested with different working angles (30o, 45o and 60o). Different SC types were used; single pass, double passes flat plate collector and double pass thermal energy storage box collector (TESB). A computational model based on the finite volume method for transient tw dimensional domains was carried out to describe the heat transfer and storage in the thermal energy storage material of collector. Also, equivalent specific heat method was employed to describe the heat storage and release in the mushy zone. Experimental results referred to an increase in thermal conductivity of paraffin wax that supported by copper foam matrix more than ten times. While the ventilation effect was still active for hours after the sun set, depending on the heat storage amount. Maximum ventilation mass flow rate with TESB collector was recorded with value equals to 36.651 kg/hr., when the overall discharge coefficient that was calculated for the system equals to 0.371. Experimental results showed that the best working angle range was 45~60o, and the highest air to the collector approaching temperature appeared to the double passes flat plate collector. Results gave greater heat storage efficiency of (47)% when the maximum solar radiation was 780 W/m2 at 12.00pm, while the energy summation through duration charge time was 18460 kJ. Computational results, depending on the equivalent heat capacity method for heat storage or release from phase change material that supported by copper foam matrix, showed the behavior of paraffin wax melting and solidification situation through periodic for charge and released heat from the solar collector. Also, these results gave agreement approaching the experimental results for the heat storage in the combined heat storage material, with standard error of 16.8%.
العلوم السياسية في العراق بداياتها ، نشأتها ، تطورها ، ومفرداتها التدريسية
The Strait of Malacca is one of the waterways of strategic, political, and economic importance. This strait has an increasing importance to its neighboring countries. The Strait of Malacca is very important for China, especially in the field of energy supply security, as the vast ma jority of energy supplies come to China through this strait. China seeks to ensure its security, especially in light of the cooperation of countries that look forward to this strait as well as the United States, and what the United States may cause to China, as many of them are at war with China over the China Sea, not to mention the countries that overlook it. The importance of the research emerges from the basic idea that the strategic importance of the Strait
... Show MorePsychological Counseling Services occupies a high position in the developed countries and that for its psychologist services for different sectors of the community members, and has been popularized until recently the wrong concept of the effect, that the psychological service is provided only to the owners of behavior is normal only, Vantage him neglect to provide psychological services a large segment of the community members who are in dire need of these services.
The counseling service is part of a global social movement seeking to emphasize the quality of life of the human and the emphasis on the value and dign
... Show MoreIslam 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
... Show Moreهدف هذا البحث إلى قياس الإجهاد الرقمي لدى طلبة جامعة بغداد، والكشف عن الفروق في الإجهاد الرقمي بناءً على متغيرات الجنس (ذكر - أنثى)، والمرحلة الدراسية (أولى - رابعة)، والاختصاص (علمي - إنساني). تألفت عينة البحث من (200) طالبًا وطالبة من جامعة بغداد، وتم تطبيق مقياس" الإجهاد الرقمي "الذي تم إعداده من قبل الباحثة خصيصًا لهذا البحث. وتم اعتماد المنهج الوصفي التحليلي وبعد تطبيق مقياس البحث وتحليل النتائج بالوسائل الإحص
... Show Moreملامح من فكرة القانون الطبيعي في حضارة العراق القديم
Bohemia AL-Kharab for Salah Salah Which contain 477Paper deal With History of Nathion This Novel Has a different styl from another IraQis Novels, this Novel has no conversation this is the basic reason Which hav this research .
The novel have 3 versions , the first one deal with explain the text in different ways , the second contains the realation ship between the text and the reader .
Which appear very clear in novel from up to down , whil the third one and the last explaine
The hermonologiq
The time bylose the relation in the novel.
The last thing is the conclusion which has the simple things conclude by the researcher from several readings to the novel
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... Show Moreيكون النبات أحد عناصر النظام البيئي Ecosystem مع المناخ والتربة والطبوغرافية والموقع وعناصر الحياة الأخرى، والنبات الطبيعي الموجود حالياً, بغض النظر عن مدى تدخل الأنسان, هو في حالة " توازن بيئي" Climax مع