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%.
This article focuses on the relationship of gender to the effectiveness of both women and men in public relations work. Its aim is to identify the extent to which public relations employees are aware of the concept of gender, and to reveal the role of the institution in determining certain roles for both women and men at work, as well as to find out which employees are most effective in public relations activities within the institution.
The researcher uses public relations employees and officials in Iraqi ministries as a research sample to capture the point of view of both parties on the effectiveness of workers in public relations based on the definition of gender. The sample consists of 396 individuals
... Show Moreהריאליזם הספרותי במשמעו הכללי מצייג אשר כל מה מציינת בה הספרות מציורים מדוייקים לסביבה ולכן
אדם. ויש להתחשב בפרטים המשותפים לחיים היומיומית.
האסכולה הריאליזטית מצטיינת בזיאנרים אין זוכים בם איזו אסכולה ספרותית אחרת . האסכולה הזאת
הופיעה בספרות העברית החדשה כתוצאה להשפעתה של הספרות העברית בספרות העולמית האחרת ,
והמספרים העבריים בתנוטה הספרותית החדשה השתדלו במאמצים גדולים למען להתפתח את התנועה הזאת
Human witnessed over the centuries many of the important issues faced by the international community was centered on human rights in general and the persecution of refugees, especially according to many forms may be directly or indirectly leaves behind economic crises, social and humanitarian push world countries to rethink the mechanisms and the feasibility of developing agreements and laws and the role of international and regional organizations to protect peoplerefugeestatus.
Praise be to God, Lord of the Worlds, and prayers and peace be upon our master and beloved Muhammad and all his family and companions. As for what follows:
هدفت الدراسة إلى التعرف على الحيوية الذاتية فضلاً عن التعرف على الفروق في الحيوية الذاتية بين الطلبة على وفق متغير الجنس (ذكر – انثى) والمرحلة الدراسية (أول-رابع) والتخصص الدراسي (علمي-انساني)، تألفت عينة الدراسة من (120) طالبا وطالبة من طلبة الجامعة، وتم تطبيق مقياس الدراسة -مقياس (الحيوية الذاتية) وهو (من إعداد الباحثة)، وقد اسفرت نتائج الدراسة عن: - إن طلبة الجامعة يتمتعون بدرجة عالية من الحيوية الذاتية. - وجود ف
... Show MoreSince Internet Protocol version 6 is a new technology, insecure network configurations are inevitable. The researchers contributed a lot to spreading knowledge about IPv6 vulnerabilities and how to address them over the past two decades. In this study, a systematic literature review is conducted to analyze research progress in IPv6 security field following the Preferred Reporting Items for the Systematics Review and Meta-Analysis (PRISMA) method. A total of 427 studies have been reviewed from two databases, IEEE and Scopus. To fulfil the review goal, several key data elements were extracted from each study and two kinds of analysis were administered: descriptive analysis and literature classification. The results show positive signs of t
... Show MoreFood comes after air and water in terms of importance in the survival of human beings, In addition, it is the support and strength of health and support, if lost or destroyed man would die or get sick and become a heavy burden on himself and his society. Food, like other sources of life, is subject to various risks and corruption comes from countless sources. Among these dangers is the result of spontaneousness, lack of knowledge or compulsion due to the interaction of variables beyond the will of the producer and the consumer, such as pollution of water, air and environment and their reflection on food consumed by people. However, we can’t deny that some reasons of corruption are intentional and resulting from a planning in advance in
... Show Moreهدف البحث إلى التعرف على مستوى الازدهار النفسي فضلاً عن التعرف على الفروق في مستوى الازدهار النفسي بين الطلبة على وفق الجنس (ذكر – انثى) والتخصص الدراسي (علمي – انساني) والمرحلة الدراسية (أول- رابع)، تألفت عينة البحث من (300) طالبا وطالبة من طلبة جامعة بغداد، وتم تطبيق مقياس البحث - مقياس (الازدهار النفسي) وهو (من إعداد الباحثة)، وقد اسفرت نتائج البحث عن: - إن طلبة الجامعة لديهم مستوى ازدهار نفسي عال. - عدم وجود فروق ف
... Show Moreوهدف البحث إلى التعرف على الاوهام الايجابية فضلاً عن التعرف على الفروق في الاوهام الايجابية بين الطالبات على وفق متغير الحالة الاجتماعية (متزوجة – غير متزوجة) والتخصص الدراسي (علمي – انساني) والمرحلة الدراسية (اول- رابع)، تألفت عينة البحث من (120) طالبة من طالبات جامعة بغداد -كلية التربية للبنات وكلية العلوم للبنات، وتم تطبيق مقياس البحث - مقياس (الاوهام الايجابية) وهو (من إعداد الباحثة)، وقد اسفرت نتائج البحث عن:
... Show Moreكان الفساد وما زال أحد المواضيع الرئيسة التي شغلت اهتمام الباحثين والدارسين في المجالات المعرفية المختلفة بضمنها المجال الإداري نظراً للتأثير السلبي والمباشر لإدارات المؤسسات الحكومية العامة على نجاح برامج وخطط التنمية في تحقيق أهدافها المجتمعية, إذ أن عملية تنفيذ هذه البرامج تقع على عاتق إدارات هذه المؤسسات في إطار التزام العاملين فيها بتحقيق الأهداف والسياسات التنموية العامة للدولة ، وحرصهم على تلبية ا
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