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%.
Differences in transversal sections and activities of geomorphological operations led to forming geomorphological shapes as river turns and river isles in watercourse in the area of study. The study showed three river turns that are Sindia turn with length 4723m, turn wave 3599 average width 267.6, Zanbour turn length 11374m, turn wave 7110 average width 307.5m,and Dojama turn with length 5876m, turn wave 4982m average width 313.4m. This difference is caused by the activity of erosion and sedimentation that led to the appearance of the length rivers turn.
The study showed that the turn of Dojama is the only corresponding turn, whereas the phenomena of corresponding never appeared in other turns in the area of study. The study also sho
يهدف البحث الحالي إلى معرفة اثر التدريس بطريقة التنقيب الحواري في حفظ النصوص الأدبية لدى طلبة قسم اللغة الكردية، اختارت الباحثة طلبة المرحلة الثانية في قسم اللغة الكردية بكلية التربية ابن رشد، للعام الدراسي
(2008-2009) ميدان لتطبيق تجربتها.
تألفت عينة الدراسة من (48) طالبا وطالبة، تم توزيعها عشوائيا إلى مجموعتين، مجموعة ضابطة (درست بالطريقة الاعتيادية) تألفت من (23) طالبا وطالبة ومجموعة تجريبية (درست بطريقة الت
Die vorliegende Forschung erklärt ein sprachliches Phänomen im Deutschen und Arabischen, dessen Aspekte die Grund-Folge-Relation (Kausalität) im Allgemeinen sowie den wirkungslosen Gegengrund (Konzessivität) im Besonderen behandeln.
In diesem Kontext wird der Unterschied der verschiedenartigen Gründe der Kausalität im Deutschen, wie wirklicher Grund (kausal), möglicher Grund (konditional) und wirkungsloser bzw. unzureichender Gegengrund (konzessiv) gezeigt.
Die theoretischen Darlegungen der konzessiven Ausdrucksmittel in dieser Forschungsarbeit werden durch diverse praktische Beispiele aus der deutschen und arabischen Literatur fundamentiert.
Das Hauptziel dieser For
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تعد الادارة الجامعية عاملا مهما واساسيا في اكمال البناء المعرفي لشخصية الطالب الجامعي لما يمثله من قدرة على قيادة العملية التربوية والتعليمية والوصول بها الى تحقيق اهدافها . وطالما كانت هذه الادارة ممثلة ابتداء من رئاسات الاقسام ووصولا الى اعلى الهرم الاداري في الجامعة مهمة في تحقيق الاهداف العلمية والتربوية فان اختيار الاشخاص للقيام بمهامها تاخذ جانبا كبيرا ومهما وذلك للاثر
... Show MoreBasically, this study aims to identify the extent to which Iraqi secondary school students use writing strategies and how proficiency level and students gender could affect writing strategy use. The study also examines the relationship between writing achievement and writing strategy use among Iraqi secondary school students. For this purpose, 140 Iraqi secondary school students were selected randomly from six different schools. Petric and Czarl’s questionnaire (2003) was adopted in the study as an instrument to collect the needed data. A software of SPSS used to analyze the collected data. The findings revealed that secondary school students appeared as low users of writing strategies; low proficient students do not show a sta
... Show MoreEuphemisms are advantageous in people’s social life by turning sensitive into a more acceptable ones so that resentful feelings and embarrassment can be avoided. This study investigates the ability of Iraqi English learners in using euphemistic expressions, meanwhile, raising their awareness and the faculty members in English teaching faculties regarding the relevance of discussing the topics that demand euphemisation. This study comprised three stages: initial test, explicit instruction with activities, and a final test for the students’ development in this domain. A test has been distributed among 50 respondents, who are at the fourth year of their undergraduate study at the University of Babylon/ College of Basic Education. The lo
... Show MoreThis study discussed modern variable in the organizational thought that is the high performance organizations in the two of Iraqi public organizations. The aim of study determines to know the level of the performance in this organizations (high or not). The data was Collected by questionnaire which contain (8) characteristics, the organizational design, strategy, process, technology, leadership, the roles, culture, and external environment). The sample contain from (76) employees;
Results points that the two organizations didn’t reach to the high level of performance, and there are significance's difference among them.
The research is to use the specifications and detection of the main and secondary causes of the problems that lead to the weakness and low quality of local production in Iraqi companies and develop appropriate solutions to them, as Iraqi companies suffer from the low quality of production, And the adoption of the requirements of ISO 9001: 2008, which contributes to the development of production processes within the company, and through the field co-operation and survey conducted for public companies affiliated to the Ministry of Industry and Minerals, The importance of the research through the statement of the most important problems facing the General Company for vegetable oil industry in terms of low and weak in production qual
... Show MoreThe drawings of The travelers artist is important historical document and sources for important information about The most of The city and building and different Islamic art which idling because of different causes like wars and destruction or natural causes and disasters like eruptions and earthquakes and floods which we cannot make a clear form about the buildings mapping in later period .
رمت الدراسة التعرف بمستويات التفكير الهندسي لدى طلبة قسم الرياضيات في كلية التربية / ابن الهيثم - جامعة بغداد، ولتحقيق هدف الدراسة تم اعتماد مقياس الحربي(2003) المعد على البيئة السعودية ويتكون من (25) فقرة موزعه على خمسة مستويات وهي (المستوى البصري ، التحليلي ، شبه الاستدلالي، الاستدلالي، المجرد وبلغت عينة الدراسة (206) طلاب من طلبة قسم الرياضيات في كلية التربية- ابن الهيثم بجامعة بغداد تم اختيارهم بالطريقة ال
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