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%.
لا يستطيع كل كائن حي أو كيان اجتماعي أداء دوره الذي يفترض أن يقوم به ما لم يمتلك الوسائل الكافية والضرورية لأداء ذلك الدور قال سبحانه وتعالى ((قال ربنا الذي أعطى كل شيء خلقه ثم هدى – طه 50)).
والنشاط الاقتصادي كجزء من الكيان الكلي للمجتمع لا يختلف عن هذه القاعدة، إذ عندما يراد من النظام الاقتصادي أداء دور فاعل فلا غنى له عن الوسائل التي تمكنه من أداء دوره المنشود. للنظام الاقتصادي مجمو
... Show MoreThat art and poetic creativity is not associated with a certain time and place and that artistic inspiration is a gift from God loved to a group of individuals so that their experiences be simulated speaking to the insides of the human self and that the creativity of the artist poet lies in the purpose of what is familiar and accepted and mocked for this purpose to
Milling Machining is a widely accepted nontraditional machining technique used to produce parts with complex shapes and configurations. The material is removed in two stages roughing and finishing, the flat end cutter removed the unwanted part of material, then finished by end mill cutter. In milling technique, the role of machining factors such as cutting depth, spindle speed and feed has been studied using Taguchi technique to find its effectiveness on surface roughness. Practical procedure is done by Taguchi Standard matrix. CNC milling is the most conventional process which is used for removing of material from workpiece to perform the needed shapes. The results and relations indicate that the rate of feed is v
... Show Moreجاء التقويم ليكون مكملا للعمليات التعليمية يساعد على الوقوف على نتائجها وسبل النهوض بها والوقوف على المعوقات التي تقف امام مسيرتها وقد عنيت عمليات التقويم باهتمام كبير من قبل القائمين على العمليات التعليمية اذ عقدت العديد من المؤتمرات والندوات واجريت العديد من الدراسات عالميا ومحليا من اجل الوقوف على هذه العملية المهمة الداعمة للتعليم والنهوض بمستويات المتعلمين ، ومن بي
... Show MoreAnhdralazuri of Yazour a village Ramle Palestine, from a religious family of Abu Mohammed Yazouri arrived in Egypt in the year (439 AH / 1036 AD), and was aimed from behind, returned him to his previous position to assume spend Ramle, Fasttaa a senior statesmen to provide Abu Muhammad Yazouri L. Caliph assuming start, Vtm him so, raising its standing and became MetwallyDiwan or caliph, in the year (441 AH / 1049 AD) was assigned the Chief Justice did not stop at that, but the era of his post of the ministry a year (442 AH / 1051 AD), having proven merit in every Matulah, The minister Yazouri of the powerful minister aspiring and employers pens won several titles did not collect it for one by the judiciary, advocacy and ministry granted C
... Show MoreFootnotes are considered as an important phenomenon in the lectures of grammar. Al-Khudari's footnote is one of the most distinguished one other than its counterparts due to the prestigious and scientific status of its author
The research studies the semantic generation structures of
commodity names in the Baghdad dialect of Arabic, specifically
those names that reflect popular taste. Through descriptive field
studies of the social use of these words
Praise be to God, who is by His Power, righteous is done, and by His help to slaves who He likes, and God bless our Prophet Muhammad envoy mercy to the worlds, and upon his family and the good mates until Doomsday.After:
The fact that cursing is the far distance and expulsion from the mercy of God, curse has been proven by him - peace be upon him - for the many varieties in the Sunnah, with indication of a permit cursing the insurgents from the people of Qibla, either saying - peace be upon him -: (the believer never be as a curser ...), what is meant by those who do not deserve damnation of those not cursed God and His Messenger, and for this we must remove words cursing from the Dictionary of our words following the examp
... Show Moreتناول هذا البحث مراجعة لعدد من الكتب التي ألفت في جغرافية العراق العربية منها والإنكليزية، وتحديداً الكتب في العصر الحديث، إذ توصل البحث الى وجود مجموعة من الكتب التي تناولت مختلف جوانب العراق الطبيعية منها والبشرية، اتضح أن بعض الكتب الجغرافية تناولت الجانب الجغرافي الطبيعي فقط، في حين أن كتب أخرى تناولت الجانب الجغرافي البشري فقط. وأخرى جمعت بين الجغرافية الطبيعية والبشرية للعراق.