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%.
The research aims to demonstrate the impact of governance mechanisms on the quality of financial reports in the light of the accounting disclosure for sustainable development represented in (accounting disclosure for economic development, accounting disclosure for environmental development, and accounting disclosure for social development) in a sample of banks listed in the Iraq Stock Exchange.
Governance mechanisms were measured by evaluating and analyzing the mechanisms in banks for the research sample consisting of (15) banks, based on the governance guide issued by the Central Bank, as well as the banks’ financial reports for the years 2016 -2018, and the dimensions of accounting disclosure for sust
... Show Moreمشكلة البحث:
يبقى الفن ولا زال في جميع حالات التعاقب البشري ومراحل التطور الانساني الاكثر انطلاقة وتميزاً في التعبير عن واقع الانسان وعن مشاعره وانفعالاته وافكاره ذات الصلة بتأثيرات البيئة المحيطة به.
والفن ولاسيما (الرسم) يمثل وسيلة من وسائل التعبير الفني بل يكاد يكون الرسم وسيلة الانسان الاولى التي عبر فيها بخطوط مرئية عن مجالات حياته وعلاقته بالبيئة التي عاش فيها، ويقينا
... Show Moreهدفت الدراسة الى تحديد الكفايات التدريسية اللازمة للطالبات- المدرسات من وجهة نظرهن وذلك للتعرف على مدى حاجتهن لهذه الكفايات التدريسية التي ينبغي امتلاكها لتحقيق الاهداف المنشودة.أشتملت عينة البحث على(100) طالبة من جامعة بغداد/كلية التربية للبنات/قسم التاريخ.تم اعداد اداة البحث وهي أستبانة مكونة من (43) فقرة خماسية البدائل هي (موافقة بشدة، موافقة،مترددة،غير موافقة،غير موافقة بشدة) موزعة على
... Show MoreThe present study discusses the problem based learning in Iraqi classroom. This method aims to involve all learners in collaborative activities and it is learner-centered method. To fulfill the aims and verify the hypothesis which reads as follow” It is hypothesized that there is no statistically significant differences between the achievements of Experimental group and control group”. Thirty learners are selected to be the sample of present study.Mann-Whitney Test for two independent samples is used to analysis the results. The analysis shows that experimental group’s members who are taught according to problem based learning gets higher scores than the control group’s members who are taught according to traditional method. This
... Show MoreThe Andalusi did not leave any poetic art without expressing his psychological and sentimental emotions and the depth of emotions and it sincerity. We found Andalusian translated his emotions into poetry and in many different subjects. The Poetic images and the analogies were plentiful in their poetry.
لما كانت الوظيفة الأساسية للغة هي الوظيفة التواصلية ، أو التبادل الكلامي بين المخاطب والمستمع ، فكان لا بد لهذه الوظيفة من آليات – لغوية وبلاغية – يستعملها المتكلم أو المرسل للخطاب الأدبي لتوجيه ذهن السامع أو المخاطب نحو ما يطرحه من أفكار ، ورؤى ، واقناعه عن طريق التواصل ، بمضمون الخطاب واستلزام سرعة الانجاز ، وتأسيساً على ذلك جاء هذا البحث لبيان هذه الآليات في الخطاب القرآني متمثلاً في سور الطور
... Show Moreاستهدف البحث الكشف عن المكانة الاجتماعية لطفل الروضة بين أقرانه ، ودلالة الفروق في المكانة الاجتماعية لاطفال عينة البحث التي تعزي الى بعض المتغيرات من خلال الاجابة عن الاسئلة الاتية :
اولاً : ما المكانة الاجتماعية لدى اطفال الروضة بين اقرانهم ؟
ثانياً : ما علاقة المكانة الاجتماعية لدى اطفال الروضة ببعض المتغيرات و ذلك من خلال اختبار الفرضيات الصفرية الآتية :
Under major developments in the field of business environment, the use of traditional budgets do not fit into these developments and adversely affect the future performance of the enterprises, which requires the transition to modern systems in the preparation of the budgets of activity based budgeting ABB because they provide a more accurate and objective estimates based on scientific foundations and practical avoided arising from the use of traditional budgeting problems, Where ABB is working better allocation of resources based on the activities of an enterprise and this positively affects the performance of the administration for the purpose of evaluating their performance according to responsibility centers and decision-making govern
... Show MoreThe present study is considered the first on this sector of the Tigris River after 2003. It is designed for two aims, the first is to demonstrate the seasonal variations in physicochemical parameters of Tharthar-Tigris Canal and Tigris River; the second is to explain the possible effects of canal on some environmental properties in the Tigris River. Water samples were being collected monthly. Six sampling sites were selected, two on Tharthar Canal and four along the Tigris River, one before the confluence as a control site and the others downstream the confluence with the canal. For a period from January to December 2020, nineteen physicochemical parameters were investigated including air and water temperature, turbidity, electrical cond
... Show MoreIt takes a long time and a lot of money to choose and provide clothes. It is soothing
necessary to care of them in order to use it another time. There is no Disposable clothes
until now, like other things in the house which we used for once then we dropped, then we
can use new one without any time or effort can be mentioned like needles, nappy, tissues
and etc.
The clothes are different; people should take care of and clean them again in order to
use them again. The right care of clothes would make them last for a long time. So, there is
no need to buy a new one instead of them in a short time. This thing provides time and
effort for the people and the family, to affect positively on the family’s budget.
We s