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%.
God Almighty has prepared for this nation men who made its glory, built its glories, and elevated it to the sublime of its glory, until it was the best nation brought out to people.
Among these notables are those who served the Noble Qur’an, and sacrificed the most precious to reveal its secrets, and to defend the Noble Qur’an against atheists and skeptics, namely Imam (Zain El-Din Muhammad Ibn Abi Bakr Ibn Abd al-Qadir al-Razi, 666 AH), that venerable scholar, and the great sea, who He was known to be: an interpreter, linguistic, jurisprudent, jurisprudence on the Hanafi school of thought. Among his most prominent books are: (Mukhtar Al-Sahah) on language, (Explanation of the Haririya Maqamat) and (Hadiqat al-Ha
... Show Moreالمستخلص تهدؾ الدراسة الى ل اٌس مدى التطب كٌ والتبن للم اٌدة ال مٌظة ف المنظمات العامة ولد اشتمت مشكلة الدراسة النظر ةٌ من وجود فجوه معرف ةٌ وذلن لملة الدراسات والبحوث الت تناولت متؽ رٌ الدراسة بأبعاده )الرؤ ةٌ المح طٌ ةٌ, التمك نٌ, الشبكات ب نٌ اعضاء الفر قٌ, الترك زٌ, الم لٌ للتعامل مع حالات عدم التأكد( اعتمدت الدراسة منهج دراسة الحالة عن طر كٌ استعمال استمارة الفحص ف المنظمة الت تم اخت اٌرها دائرة العمل والتدر ب
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ABSTRACT
A field experiment was carried out in the fields of the college of agricultural engineering sciences, university of Baghdad during the fall season of 2021, in order to find out which of the cultivated genotypes of maize are efficient under nitrogen fertilization. The experiment was applied according to a RCBD (split plot design with three replications). The genotypes of experiment (Baghdad, 5018 and Sarah) and supplying three levels of nitrogen fertilizer, which are N1 (100 kg/ha), N2 (200 kg/ha) and N3 (300 kg/ha), the results of the statistical analysis are showed the superiority of the cultivar Sarah in the trait of number of days until 50% silking, chlorophyll
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This research was conducted to test the hypothesis (There is no significant moderating effect for Dramaturgy on the relationship between impression management strategies and PTSD), (45) employees in Iraqi drilling company (Basra province) were selected as a sample. Findings showed that the percentage (0.91%) of the employees who are exposed to accidents as a result of work suffer from post traumatic stress disorder, which negatively affects their organizational behavior, thereby, reducing future performance, findings also showed that the employment of impression management strategies will assist management to address PTSD among employees wh
... Show MoreTo the Banks capital several uses, including the protection of deposits and this was approved by the Basel Committee, And Finance long-term investments which intended to investment in fixed assets that are essential to the continuation of banking activity, Fixed assets not financed from the funds of the deposit, but the owner equity do this jop. the current research tries to prove the effect of banks capital on fixed assets for a sample of iraqi private banks (bank of baghdad and Iraqi middle east Investment bank), for the period from 2011 until 2014. The research concluded that the capital of bank of baghdad affect on his total fixed assets by (84%), and the capital of Iraqi middle east Investment bank affect on his total fixed assets b
... Show Moreيهدف البحث الى قياس مدى التطبيق والتبني للقيادة الملهمة في المنظمات العامة، وقد اشتقت مشكلة البحث النظرية من وجود فجوة معرفية وذلك لقلة الدراسات والبحوث التي تناولت متغير البحث بأبعاده (الرؤية المستقبلية، الثقة بالنفس، تمكين العاملين، ادارة التغيير)، واعتمد البحث المنهج التحليلي عن طريق استعمال الاستبانة في المنظمة التي تم اختيارها وذلك لكونها تعد من المنظمات الاساسية في تقديم الخدمات التعليمية المهمة في
... Show MoreThe audit committees are considered to be one of the most important committees because of the role they play in supervising and monitoring the process of formation of the financial statements and correction of the internal supervising system also strengthening the independency of the internal and external audit. Matters which increases the efficiency and integrity of the financial statements which reflects positively on competence of board of directors and then enhance the position of the company through increasing the trust of the users of the financial statement within the company.
Therefore, this research deals with the evaluation of the performance of the audit committees in Iraqi banks according to the local rules and
... Show MoreThe Abbasid period is one of the most fertile Islamic ages attention to the bookcases have been prominent of each of the caliphs, ministers and dignitaries acquisition of books and stop in the coffers of public books, so that the largest number of students of science to see them. Baghdad's portfolio of scientific status in the late Abbasid times, which was characterized by weakness and division
هدف البحث الى تعرف :
1- مستوى الثقافة التنظيمية لرؤساء الأقسام العلمية في كليات جامعة بغداد.
2- الأهمية النسبية لأبعاد الثقافة التنظيمية لرؤساء الاقسام العلمية في كليات جامعة بغداد.
بلغت العينة (380) تدريسي وتدريسية من الأقسام العلمية في كليات جامعة بغداد المتمثلة بـ (كلية الهندسة، كلية العلوم، كلية الإعلام، وكلية التربية للبنات)، اعتمدت الاستبانة أداة لتحقيق أه
... Show MoreFind extract This research aims to find out (after learning strategy cells in the development of critical thinking and reflective thinking at the fifth-grade students in the geographic literary material). And follow researcher Almhnj demo for the purpose of achieving the goals of current research and design on an experimental group and a control with a test group after me and adopted chose researcher sample Find a way Mqsidih students of junior high Kadhimiya Boys of the breeding Baghdad / Karkh II and to verify the effectiveness of the search coined researcher hypotheses following cases: - 1. No statistically significant between the mean scores of the experimental group and the students taught her students that strategy differences (lea
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