The present study involves experimental analysis of the modified Closed Wet Cooling Tower (CWCT) based on first and second law of thermodynamics, to gain a deeper knowledge in this important field of engineering in Iraq. For this purpose, a prototype of CWCT optimized by added packing under a heat exchanger was designed, manufactured and tested for cooling capacity of 9 kW. Experiments are conducted to explore the effects of various operational and conformational parameters on the towers thermal performance. In the test section, spray water temperature and both dry bulb temperature and relative humidity of air measured at intermediate points of the heat exchanger and packing. Exergy of water and air were calculated by applying the exergy destruction method on the cooling tower. Experimental results showed a significant performance improvement when using packing on the CWCT. It can be observed that the thermal efficiency for the CWCT with packing under a heat exchanger and CWCT with packing above the heat exchanger are approximately 40% and 25% higher than that of the CWCT without packing respectively. As another part of the experiment results, it is indicated that the exergy destruction is directly proportional to air flow rate, cooling water flow rate, inlet cooling water flow rate and inlet Air Wet Bulb Temperature (AWBT) whereas, it is inversely proportional with spray water flow rate. In comparison with the cooling capacity of the tower, it was found that the exergy destruction approximately less than 20%. Exergy efficiency behavior is inversely proportional with the behavior of the exergy destruction. Empirical correlations are obtained to predict water film heat transfer coefficient and air-water mass transfer coefficient considering the influences of operational parameters.
هدف البحث الحالي الى قياس اسلوب الفكر المثالي عند طلبة قسم الكيمياء، كلية التربية للعلوم الصرفة ابن الهيثم. وقياس مدى الفكر المثالي حسب الصف الدراسي للمرحلة الجامعية. ولتحقيق هدفا البحث تم اتباع المنهج الوصفي. وتم تحديد مجتمع البحث بجميع طلبة قسم الكيمياء وللصفوف الاربعة ( الاولى ، الثانية، الثالثة، الرابعة) . وتم اختيار مجموعة من كل صف دراسي لتكون عينة للبحث الحالي. وتم اعداد اداة لقياس التفكير المثالي عند ع
... Show Moreهدف البحث الى الكشف عن فاعلية استراتيجية المماثلة في تحصيل مادة الكيمياء والذكاء الانفعالي لطلاب الصف الخامس العلمي الاحيائي. وتكونت عينة البحث من (28 ) طالبا من طلبة الصف الخامس العلمي الاحيائي في اعدادية الشاكرين للبنين, التابعة لمديرية تربية بغداد – الكرخ الثانية, موزعين بين شعبتين بالتساوي, شعبة (أ) وهي المجموعة الضابطة التي درست على وفق الطريقة الاعتيادية, وشعبة ( ب) وهي المجموعة التجريبية والتي درست على و
... Show MoreLes sociétés d’assurances sont considérées parmi les importantes entreprises financières non bancaires.
Pour que ces sociétés assurent sa continuité d’existence, il faut qu’elles veillent au rendement financier qui représente ses différentes actions durant une période déterminée, en effectuant une évaluation permanente en utilisant de différentes méthodes parmi lesquelles l’analyse financière avec ses aspects divers.
L’objectif de cette étude est d’évaluer le rendement financier des sociétés d’assurances et où projette l’étude sur la société Algérienne d’assurance durant la période 07- 09.
On the research that is marked by the historical development of the Supreme Federal Court in Iraq accordance with the issued legal legislations Research Submitted by Adel Amran Hamad Faculty Member, the college of Biotechnology
The current study aims at investigating the effect of cooperative learning (Jigsaw) on motivation of female students. Department of kindergarten to learn Human biology. This is of be dove through verification of the hypothesis that there is no significant difference at the 0.05 level between the motivation of experiment of group subjects who study according to (Jigsaw) cooperative learning and that of the control group subjects who study traditionally.
The study is limited to female students al the first year-Department of kindergarten college of Education for women university of Baghdad during the academic year 2007-2008.
An experiment of design of partial control and post-test for two groups is used. The experiment groups consist
تعتبر كرة القدم لعبة شعبية معروفة في جميع أنحاء العالم، وهناك العديد من المباريات تلعب يوميا بمختلف المستويات، ولقد فتن الناس بلعبة لا يمكن التنبؤ بنتائجها، ويمكن تحديد نتيجتها في ثوان معدودة عن طريق التحركات غير العادية للخصم أو الأخطاء الدفاعية القاتلة وغالبا ما يلعب حارس المرمى دورا حاسما في نتيجة المباراة ، حيث تعتمد كرة القدم بشكل اساسي على الامكانيات المهارية للاعبين واستغلال هذه الامكانيات بالشكل ا
... Show MoreThe estimation of the parameters of Two Parameters Gamma Distribution in case of missing data has been made by using two important methods: the Maximum Likelihood Method and the Shrinkage Method. The former one consists of three methods to solve the MLE non-linear equation by which the estimators of the maximum likelihood can be obtained: Newton-Raphson, Thom and Sinha methods. Thom and Sinha methods are developed by the researcher to be suitable in case of missing data. Furthermore, the Bowman, Shenton and Lam Method, which depends on the Three Parameters Gamma Distribution to get the maximum likelihood estimators, has been developed. A comparison has been made between the methods in the experimental aspect to find the best meth
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ملخص الدراسة
سعت الدراسة تعرف اثراستعمال الأنموذج المعملي في تصحيح المفاهيم الرياضية شائعة الخطأ لدى طلاب الصف الأول المتوسط بالإجابة عن السؤال "ما اثر استعمال الأنموذج المعملي في تصحيح المفاهيم الرياضية شائعة الخطأ لدى طلاب الصف الأول المتوسط" ولتحقيق هدف الدراسة وضعت الفرضية الصفرية "لايوجد فرق ذو دلالة إحصائية عند مستوى الدلالة (0.05) بين متوسطي درجات طلاب المجموعة التجريبية الذين يدرسون المادة المقرر
This research investigates the methods of producing Investigative Arabic Television Programs that are able to prove its existence during a short period of time as a form of Television programs on Arab satellite channels growing in number and varied in content. The research aims to present qualitative and quantitative descriptions of the methods used in tackling the topics discussed in the program, and knowing whether they satisfy the conditions and scientific foundations for the research, investigation, analysis, and interpretation. The researcher uses the survey method and uses the tool of content analysis including a set of methodological steps that seek to discover the implied meaning of the research sample represented by the program
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the study of social phenomena in this direction is, the sign of deviousness to the segments of the circumstance with their conditions and circumstances, then pointed to the uniforms that they were adorned by the tortillas as well as shirt Safaf from good linen soft and touched the country and the good and others.