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%.
يهدف البحث الى التعرف على اثر استراتيجية نجمتين وامنية في تحصيل مادة الكيمياء عند طلاب الصف الثاني المتوسطولتحقيق هدف البحث تم اتباع المنهج التجريبي ذو الضبط الجزئي وتم تحديد مجتمع البحث بطلاب الصف الثاني المتوسط لجميع المدارس الثانموية والمتوسط التابعة لمديرية تربية الكرخ الثانية وتم اخنيار احد هذه المداس بصورة قصدية لتطبيق تجربة ابلبحث الحالي
الملخص (باللغة العربية) شكّل اجتياح العراق للكويت في 2 آب/أغسطس 1990 اختباراً حاسماً لقدرة جامعة الدول العربية على إدارة الأزمات الإقليمية وصياغة موقف عربي موحّد إزاء انتهاك واضح لسيادة دولة عضو. غير أن أداء الجامعة خلال أزمة الخليج الثانية كشف عن حالة من الشلل المؤسسي والإجرائي، تجلّت في بطء اتخاذ القرار، وتنازع التأويلات حول شرعية الإجراءات، وتوظيف نصوص الميثاق بما أعاق إنتاج قرار عربي حازم وقابل للتنفيذ. تن
... Show MoreTwo Prototypes of Transversely Excited at atmospheric pressure (TEA) Nitrogen laser systems (One Stage Blumlein Circuit and Two Stage Blumlein Circuit) were fabricated and operated. High voltage power supply with variable operating voltage (0-20 kv) and operating current (1-3A) was built and tested successfully. The gas flow rate of 15 L/ min and 10 L/ min for OSBC and TSBC was used. The performance of the fabricated systems was studied extensively reaching to the optimum operating conditions. The obtained laser output energy for the first system has linear relationship with the applied voltage. The maximum output energy was about (1.14 mJ) with (10.40) ns pulse duration and the half-wave divergence angle was about (0.1455 m rad). In the
... Show MoreThe aim of this research is to make a new investigation of a scientific thesis in Arabic Morphology in which an allusion occurred in relation to its real author and its title, there is alot of dropping and flaw when it was first applied due to depending on one written transcript
هدف البحث الى التعرف على القياس المحاسبي عن التنمية المستدامة، وبيان العلاقة بين القياس المحاسبي عن التنمية المستدامة وتقارير الابلاغ المالي، وكذلك بيان أثر القياس المحاسبي عن الاستدامة على تقارير الإبلاغ المالي في الشركة العامة للمنتوجات الغازية، وقد تمحورت مشكلة البحث في بيان أثر عناصر المحاسبة عن التنمية المستدامة، البيئية، والاجتماعية، والاقتصادية، على تقارير الإبلاغ المالي في الشركة العامة للمنتو
... Show Moreهدف ال الأسلوب المعرفيّ م الإد ا ركيّ اضة للبنات، والتعرّف على علاقة التنظ ة وعلوم الر ة البدنّ ة التر لّ ة في ات المرحلة الثانّ طال إنّه احثتان اضة للبنات، وأفترضت ال ة وعلوم الر ة البدنّ ة التر ل ة في ات المرحلة الثان عض طال التأمّليّ الاندفاعيّ لدى اس الأسلوب المعرفيّ التأمّليّ الاندفاعيّ لدى عیّنة م الإد ا ركيّ ونتائج مق اس التنظ ة بین نتائج مق
... Show MoreAbstract:
Purpose\The researcher paper aims to determine the impact of information technology on the job performance, for Iraq private ban as through the use of technology dimensions of job performance.
The aim of this research: this study aims to discuss the importance of information technology and its role in achieving job performance and its impact on the Iraq banking sector design/ methodology/ approach used entrance design/methodology/approach- pilot, the questionnaire was used to collect data in order to develop a model to measure reliably and correctly to the variables of information technology and job performance, and hypotheses were tested through the use of some statisti
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the Objective of study is to measure the quality of medical service level, in the Iraq public hospitals ,presented by special words ,private hospitals, and compare between them, by knowing the level of recipients satisfaction of medical service for all dimensions of quality service, and then measuring satisfaction with the quality of medical service as a whole for both of them, which have been prepared in questionnaire form, included two main directions, first to determine the level of satisfaction when, recipients of medical service is not dimensions quality of service in accordance with the Scale Servqual by (Parasurman et .al 1988), consisting of five di
... Show MoreAbu Al- Qasim Qa ,im Maqam is famous figure in political life of lranian; The life of Abu Al- Qasim Qa ,im Maqam is full of incidents and conflicts in the period of the expansion of foreign influence in lran Abu Al- Qasim Qa ,im Maqam has an important role in the history of Iran Modern political considered him one of the most prominent leaders to the unified Arabian nationalistic liberating Abu Al- Qasim Qa ,im Maqam raised in the history of the Qajar .