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%.
It is summarized that Abu-Baker Al-Soly is one of Arabic Muslim scientists who had special style in literary writing specifically in sciences and knowledge that had depended on the encyclopedia culture gained from various fields of science , this means that he was an individual who had participated to characterize features of Islamic –Arabic history enhanced the rules of it , this matter would encourage us to know the method and style of writing in the field of intellectual life in which the writer depended on the procedures direction of scientists that he lived in the Abbasid era .
الحديث عن محمد بن إسحاق النديم حديث عن عالم جليل كان له فضل تصنيف سفر خالد من أسفار المعرفة و العلم و سجل ضم عناوين ما أنتجته الأمة العربية الإسلامية في وقت عزها و مجدها و سطوع كوكبها في سماء الدنيا ، فجاء هذا الكتاب جامعا نافعا في بابه .
Si le rire est censé être le propre de l'homme, il n'en est pas pour autant toujours signe d'intelligence. Qui n'a jamais eu honte d'avoir ri àune blague idiote ou méchante?
Il y a plusieurs façons de rire , ce qui fait que ce qui est comique pour les uns ne l'est pas pour les autres et que le comique réside moins dans l'objet ( situation, blague..) que dans le point de vue et dans l'interprétation que nous en ferons. " Le rire .. contient toutes les mélancolies humaines ([1]) ".
... Show Moreشغلت نظرية العدل الإلهي بال الأديب العراقي القديم، مما جعلته يثير عبر نصوصه الأدبية كثير من التساؤلات حول عدالة الإلهة، التي يعبدها ويقدم لها الهدايا وتساؤلاته هذه دفعت بالباحث إلى اختيارها عنوانا لموضوعه، إلا أن الدراسة ستختصر على نصوص معينة، والسبب في ذلك أنها كانت الرائدة في هذا الجانب، وفي اللحظة التي ينتقي فيها العدل الإلهي وتتحول الإلهة إلى كلاب تلهث وراء غرائزها، ذهبنا وراء الأسباب التي قادت إلى فقد
... Show Moreاصبحت الاسواق المالية في الوقت الحاضر من المتطلبات الأساسية لتحقيق التطور الاقتصادي والمالي وتبرز اهمية السوق المالي في خدمة الاقتصاد الوطني العراق حيث ان سوق العراق للأوراق المالية (بالإنجليزية: ISX) هو سوق للأوراق مالية في بغداد وتأسست السوق في
... Show MoreThe design of fabrics and fashion is manifested by aesthetic advantages betting with the movement of society in its quest to develop as an independent art in itself that is linked to the values and aesthetic concepts of other arts and what appears in them of intellectual systems calling for renewal and modernity. Which brought about a wide change in public taste, as well as a desire for innovation . Which made fashion an interesting aesthetic phenomenon and taste is always subject to change constantly to comply with the social variables that occur in human life, as the fashion that appears in a certain era of time and takes a great distance from spreading as something new and out of the ordinary is in fact the fruit of the development of
... Show MoreThe conflicting duality of goodness and evil has a psychological effect on the life of humans, the nature of human beings is originally goodness whereas the tendency of evil flows from the society, therefore the first who found a meaning of evil on earth is kabeel when he quarreled fiercly with his brother who carried in himself all the meanings of goodness and toierance.
In this paper of mine we find that Robaayat Al khayam carries a poetic content of a special meaning in that every expression reflects semantic relationship (the good played a part in the formation lies with and the evil) of which its foundation lies with the human personality (soul), and he (the poet) a scribes it to matters of
... Show MoreThe goal of health awareness is to familiarize people with health information and facts, and make them realize their sense of responsibility towards their health and the health of others. And translate that goal in practice through applying healthy and sound behaviors spontaneously. This, the goal, is pursued by health awareness announcements through employing announcement persuasion of health as one of the methods of influencing the masses to adopt ideas, behaviors, and adherence to health advice and guidelines; The study aims to analyze the content of the Ministry of Health and Environment announcements regarding health awareness and to reveal the most employable persuasions in health awareness announcements
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