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%.
Abstract:
The research sought to identify the crises that occurred during the research period and their reflection on the performance of the hotel Research sample as well as to identify the reality of auditing the hotel Research sample and the preparation of a performance audit program can be adopted in auditing the performance of hotels in light of crises, and the problem of the research lies in the lack of a program to audit the performance of hotels that takes into account the crises experienced by the hotel sector, The research was based on solving its problems on three hypotheses, the first is that the performance audit in light of the Covid-19 pand
... Show Moreتعد التغيرات المناخية قضية بيئية عالمية وشاغلاً مشتركاً للبشرية وهي نتيجة حتمية للتطور الحضاري، لاسيما بعد قيام الثورة الصناعية، فقد كان الاستهلاك غير العقلاني لموارد الطبيعة والتوسع العمراني على حساب المساحات الخضراء آثار خطيرة على المناخ الذي يعد من اهم عناصر البيئة الطبيعية لما له من اثر واضح على كافة مجالات الحياة. على صعيد الحالة العراقية يواجه العراق تحديات عدة يفرضها تغير المناخ كارتفاع درجات الحرا
... Show MoreEl color es uno de los elementos novelísticos que ayudan los autores para desarrollar las acciones y llevarlas al desenlace adecuado. Y Blasco Ibáñez depende al color para pintar las escenas artísticas dentro sus novelas, especialmente, sus novelas que pertenecen al siglo de naturaleza. Él conocido con la abundancia de los colores para describir el ambiente y los personajes, como indica el autor catedrático José A. Balseiro:
"su pluma no supo__ como el pincel de los primitivos__ del matiz logrado a toques mínimos, pacientes. ¿No era, a caso, coterráneo de Joaquín Sorolla, en cuya paleta mediterránea celebrábase, día tras día, el milagro del f
... Show MoreDans le roman moderne, le type du héros est depuis longtemps devenu suspect. Il risque même de disparaitre dans ce qu´on désigne le Nouveau Roman qui, se concentrant plutôt sur les objets, décrits minutieusement, refuse la fonction épistémologique traditionnelle de la littérature. Cette conception se manifeste, sur le plan formel, par certains traits typiques, comme la relativisation des points de vue, la décomposition de l´action, la destruction du temps, la décomposition de l´espace et la désintégration du personnage romanesque dont les liens avec la société sont coupés.
This research aims at identifying problems that the Iraqi widow woman suffers from. The research is limited to a Sample of terrorism victims widows which is up to (70) widows from Al-Amal center for widows and orphans care in Baghdad. <
... Show MoreMedia writing is accuracy writing. Clarity and concision are its predominant features. It is a writing that goes straight to the essence because it has no time to waste. Furthermore, it must be as accurate as scientific writing. It is destined for the average reader and has to be understood by everyone. However, it can be as elegant as literary writing. The variety in its forms of expression does not prevent media writing from having its own amplitude.
In short, this study is a practical approach that aims at studying different kinds of writing styles and identifying the specificity of media writing using some patterns and examples
أن الامم والشعوب لاتستطيع المحافظة على استمرار وجودها وتقدمها ورقيها، إلابفضل إعداد اجيالها المتعاقبة الاعداد السليم المتكامل ، وبقدر ما تحافظ الامم والشعوب على تربية هذه الاجيال للتمسك بدينها ، ومعتقداتها ، واخلاقها ، بقدر ما تحافظ على بقائها وعلو شأنها ، وكما فطنت الامم والشعوب إلى اهمية تربية اجيالها ، فطن اعداؤها الى ضرورة التخريب في جذور البناء الصحيح لتربية الاجيال ( فاطمة ، 1998، ص2).
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When we study the history of dentistry we can investigate some methodology styles which lead us to psychology – dentistry or take the relationship between psychology and dentistry, and this type of specialization which is Medical psychology has its own methodology and subjects, as the historical sequence in this filed lead to how evolution occurred in this branch of medicine, which was accompanied by many factors , and this factor that contributed to the consolidation of the misconceptions about the social, family and the media culture and gave a distorted picture of Dentistry and the attending physician or dentist and show him as someone tough , ruthless and violent in his dealings and style , these pro
... Show Moreجدلية التنظرية في الذاكرة المنظمة بين متاهة النماذج الصناعية وواقعيةالنموذج الهجين