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%.
In this paper the use of a circular array antenna with adaptive system in conjunction with modified Linearly Constrained Minimum Variance Beam forming (LCMVB) algorithm is proposed to meet the requirement of Angle of Arrival (AOA) estimation in 2-D as well as the Signal to Noise Ratio (SNR) of estimated sources (Three Dimensional 3-D estimation), rather than interference cancelation as it is used for. The proposed system was simulated, tested and compared with the modified Multiple Signal Classification (MUSIC) technique for 2-D estimation. The results show the system has exhibited astonishing results for simultaneously estimating 3-D parameters with accuracy approximately equivalent to the MUSIC technique (for estimating elevation and a
... Show MoreThis research is Interested in how the performance and implementation of factory production engine coolants of the General Company for Electrical Industries of its work, and to facilitate the flow of the decisions of senior management and access to all configurations, to ensure differentiation desired and reduce lost sales, resulting from poor scheduling of operations through the application of certain rules of scheduling operations in the production plant Engines Air-cooler, the objectives of research in identifying the best base and working to reduce the time and cost of Same Rules of Process which are considered the most influential of any organization and thr
... Show MoreIn this research, the focus was placed on estimating the parameters of the Hypoexponential distribution function using the maximum likelihood method and genetic algorithm. More than one standard, including MSE, has been adopted for comparison by Using the simulation method
It takes a long time and a lot of money to choose and provide clothes. It is soothing
necessary to care of them in order to use it another time. There is no Disposable clothes
until now, like other things in the house which we used for once then we dropped, then we
can use new one without any time or effort can be mentioned like needles, nappy, tissues
and etc.
The clothes are different; people should take care of and clean them again in order to
use them again. The right care of clothes would make them last for a long time. So, there is
no need to buy a new one instead of them in a short time. This thing provides time and
effort for the people and the family, to affect positively on the family’s budget.
We s
يتناول البحث جزئية من جزئيات موضوع الفسخ المبتسر للعقد
ان مرتكزات السياسة الخارجية العراقية لمرحلة ما بعد العام 2003 قد عكست توجهات ايجابية قادت الى صياغة مجموعة من الرؤى والتصورات الاستراتيجية الجديدة التي افضت الى اعتماد وتوظيف الوسائل والقنوات الدبلوماسية بوصفها وسائل فعالة وبطريقة متكاملة ومتوازنة من اجل تعزيز مستويات الاداء الفعلي وتحقيق جميع الاهداف المستقبلية للسياسة الخارجية العراقية في ضوء صياغة معادلة مفادها: تدعيم وترصين اداء مؤسسات صنع السياسة ال
... Show MoreThis study sought to give a general picture of the organizations and formations of the ground forces of the Abbasid army in its first era, in preparation and armament and continuous development of the mechanisms to help maintain the moral and spiritual morale in the fighting.
Therefore, the caliphs' interest in building the army, organizing it, arming it, choosing competent leaders, and providing them with various weapons in terms of production and storage, as well as taking care of fortifying the cities and gaps in determination and determination, and embarked on construction and restoration, where amazing speed and acted according to the circumstances. During the first Abbasid era, there were significant developments in the military
يهدف البحث الحالي الى معرفة أثر انموذج بوسنرفي تحصيل مادة الرياضيات لدى طلاب الصف الثاني المتوسط .
ولتحقيق هدف البحث صاغت الباحثة الفرضية الآتية :
لا يوجد فرق ذو دلالة إحصائية عند مستوى (0,05) بين متوسط درجات طلاب المجموعة التجريبية الذين درسوا مادة الرياضيات وفق انموذج بوسنر، وبين متوسط درجات طلاب المجموعة الضابطة الذين درسوا المادة نفسها بالطريقة الاعتيادية في اخت
... Show MoreThe aim of the research is to find out the effect of the SPAWN strategy on the life skills of second-intermediate-grade students. This study stage represented the research community within the intermediate and secondary governmental daytime schools affiliated with the Directorate of Education of Diwaniyah. The experiment was applied in Al-Razai Intermediate School on a sample of second-grade intermediate students, including 66 students distributed into two groups: (32) students within the experimental group and (34) students within the control group. The two groups were equivalent with a number of variables (chronological age, intelligence test, previous information test, life skills scale). The results indicated that the two groups were
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