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.
The aim of this research is to make a new investigation of a scientific thesis in Arabic Morphology in which an allusion occurred in relation to its real author and its title, there is alot of dropping and flaw when it was first applied due to depending on one written transcript
The City of Ember is a very interesting novel that is although intended for young readers, have so many layers and messages that are misunderstood. In this research, both the novel and the film adaptation are studied with the intent to decode the warning messages that the novelist and the director tried to introduce to the audience. The research studies four vital messages; the first message is that history repeats itself for the novel has many allusions to the history of Jews and their painful holocaust and even goes back in history the days of Moses and the Exodus, the second message tackles the conspiracy theory that states nothing happens by accident and that everything is planned and connected hence comes the third message
... Show Moreهدف البحث إلى إعداد تمرينات منطقة الشدة الثالثة للقوة المميزة بالسرعة للرجلين للاعبين الشباب بكرة القدم، والتعرف على تأثير تمرينات منطقة الشدة الثالثة للقوة المميزة بالسرعة للرجلين في السرعة الانتقالية وفي سرعة التهديف للاعبين الشباب بكرة القدم، وأفترض الباحث بأنه توجد فروق ذات دلالة إحصائية بين نتائج الاختبارات القبلية والبعدية لمجموعتي البحث التجريبية والضابطة لكل من السرعة الانتقالية وسرعة التهديف ب
... Show MoreThis research work dealt with the problem of layout the production line of engine of fan roof at the General Company for Electrical Industries (GCEI). It was observed that the assembly line of engine was unstable and subject to severe fluctuations. In addition the execution of tasks at some stations was observed to be very fast while at other stations was slow. This phenomenon resulted into bottlenecks between workstations, idle time, and work in process. The system design was used to assign tasks to work stations according to different heuristics (Ranked Positional weight techniques, longest Task Time, Most following tasks, Shortest tasks time, Least number of following task).
The study revealed that th
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استخلص عامل التلزن من E. faecalis EM1 بعد تكسير بالكرات الزجاجية والترسيب بالكحول الاثيلي , واجري فحص التلزن وقياسه لمستخلص لخلايا E. faecalis مع انواع من البكتريا السالبة لصبغة غرام تضمنت Escherichia coli و Klebsiella pneumonia و Serratia marcescens و Pseudomonase aeruginosa و Salmonella typhi , بينت النتائج ان اعلى نسبة تلزن للخلايا والمستخلص تكون مع بكتريا ٍK. Pneumonia حيث بلغ66.5 % مقارنة بالسيطرة79.5 % , واوطا قيمة للتلز
... Show Moreتم استخدام خرائط ضبط الجودة الإحصائية لتقييم جودة الخدمة التعليمية في جامعة الباحة، ويهدف هذا البحث إلى استخدام خرائط ضبط الجودة الإحصائية لقياس مستوى الجودة وفجوة الجودة بين توقعات الطلبة وإدراكاتهم لمستوى الخدمة الذي تقدمه جامعة الباحة. حيث تم اختيار عينة من 200 طالب وطالبة عشوائيا باستخدام العشوائية العنقودية من 4 كليات خلال الفترة 01 – 30/2015م، وجمعت البيانات من خلال استبيان جودة الخدمة الذي يقيس ت
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المستخلص
يعد تقييم اداء العاملين احد اهم الركائز الاساسية التي يتوقف عليها نجاح أي منظمة تسعى بأن تتطور وتتميز بأنشطتها واداءها وبالأخص المنظمات التي لها خصوصية في عملها كالأجهزة الرقابية التي تعتمد في اداء انشطتها ومسؤولياتها على كفاءة مواردها البشرية, ومن هذا المنطلق يهدف هذا البحث الى تصميم انموذج ثلاثي المحاور (المؤهلات والقدرات، الاداء والانجاز، التعاون والالتزام الوظيفي) ثُماني المستويات
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