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%.
Prince Kikaus explained to us Conditions of writing and establishing .Then he touched upon the Conditions of the ministry and qualities that must be characterized Author and minister both need machines must be availabla in person if given these positions .he was creative in presenting his ideas which is not without judgment an knowledge.He had a distinct style in mentioned professions and administrative hierarchy As explained in his speech About the writer and his Correspondence and construction and writer position who has developed into a minister then he touched it to the cabinet system and what the minister should do.of qualities .and the importance of the post of minister who mentioned several points to him ou
... 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.
Nuclear shell model is adopted to calculate the electric quadrupole moments for some Calcium isotopes 20Ca (N = 21, 23, 25, and 27) in the fp shell. The wave function is generated using a two body effective interaction fpd6 and fp space model. The one body density matrix elements (OBDM) are calculated for these isotopes using the NuShellX@MSU code. The effect of the core-polarizations was taken through the theory microscopic by taking the set of the effective charges. The results for the quadrupole moments by using Bohr-Mottelson (B-M) effective charges are the best. The behavior of the form factors of some Calcium isotopes was studied by using Bohr-Mottelson (B-M) effective charges.
Abstract
The study deal with two main variables:- the dimensions of distribution, and the customer loyalty . the researcher has chosen samples of Iraqi newspapers like (AL Sabah, AL Mada, AL Bayna aljdeida newspaper), because this product depends greatly on the consumption of customers so as to achieve the success. After studying the dimensions of these variables ( cost, flixibilty & deliver time ) which concerns the distribution, and for these dimensions ( marketing relationship, customer perception, customer experience, brand, & product quality) which relate to the customer loyalty . the problem has been identified in a number of remarks concerning the extent of awareness that the administration
... Show MoreThe aim of the current study is to identify the level of goal conflict with twelfth-grade students in South Sharqiah/ Sultanate of Oman according to gender and specialization. The study used the descriptive method. A scale of (28) items was developed and divided into six dimensions: time pressure, goal achievement, limit of power, limit of budget, incompatible strategies, and unclear task. To validate the scale, it was piloted (40) students. The scale was administered to a sample of (402) students (209) males in the Governorate of South Sharqiah. The results showed that the conflict level was high in “unclear task”, and an average conflict level in “limit of power”. Other dimensions (goal achievement, time pressure, limit of powe
... 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 :
The 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 MoreThis study attempts to highlights on the evaluation of performance efficiency for Investments in both National & Iraqi Insurance companies for the years 2001-2010 and their importance on those companies and the economy of the country in order to find out the investment areas and to compare between investment activity and its revenues as well as to compare performance of both companies in investment field.
The study was based on annual reports and balance sheets of both companies. In many chapters, this study dealt with theoretical and practical aspects of the investments and its revenues. Key hypothesis was based on this study, including four parts of Sub hypotheses about (statistical effective relationship between the
... Show MoreThe importance of economic and technical feasibility studies include all of the investor, the society, the banks, the project and the government. As it will assist in achieving the optimal use of the available economic incomes on the national level and arranging the projects in priority which participates in achieving the government benefit without wasting the amounts .This is the research goal So, the research covered its theoretical aspect, of SAIs and the economic and technical feasibility studies then the role of the auditors in auditing those studies Then a mechanism was proposed includes a guidebook that provides guidelines for organizing the process of preparing and auditi
... Show Moreدرست الباحثة البنية الإيقاعية عند الشاعر الصقلي