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.
הקדמה
המילה היא יחידה בסיסית ב שפה המתאפיינת בכך שיש לה משמעות ייחודית וביטוי פונטי )בשפה מדוברת (, גרפי
)בכתיבה( או מרחבי )בשפת סימנים. ובעיקר המונח מילה מתייחס ל שפות טבעיות או לשפות מתוכננות , אבל הוא קיים
גם בשפות מלאכותיות כגון שפות תכנות או שפות לוגיקה . בית היא מהמילות שראינו צריך לחקור אותה מתוך
משמצאנו בה מתפקידים גדולים בפעולה חשובה בתולדות הלשון עהברית שהיא התחדיש, פעולה זו שנכנסה לעברית אחרי
Background: Acne is a common disorder experienced by adolescents and persists into adulthood in approximately 12%–14% of cases with psychological and social implications of high gravity. Fractional resurfacing employs a unique mechanism of action that repairs a fraction of skin at a time. The untreated healthy skin remains intact and actually aids the repair process, promoting rapid healing with only a day or two of downtime. Aims: This study, was designed to evaluate the safety and effectiveness of fractional photothermolysis (fractionated Er: YAG laser 2940nm) in treating atrophic acne scars. Methods: 7 females and 3 males with moderate to severe atrophic acne scarring were enrolled in this study that attained private clinic for Derm
... Show MoreAbstract The Kenyan policy towards Somalia was influenced by a set of interrelated factors between the two countries and stemmed from the internal environment and most prominent: the geographical factor, ethnic, cultural, religious, political, economic and security, has been dominated by this policy since independence from the British colonial administration in the sixties of the last century and so far the nature of instability and tension, As the two countries are geographically contiguous and as security risks escalate, Kenya in 2011 rushed military action against Somalia, the first military action by Kenya outside its borders since independence.
خليفة بن خياط بن خليفة الشيباني ألليثي العصفري البصري، أبو عمرو، ويعرف بشَبَابه، الفقيه، المُحدَث، الأديب، المؤرخ، النسَابة، وهو سليل أسرةِ اشتهر أبناؤها بالعلم، وأنجبت عدداً من العلماء الأفاضل، الذين عرفوا في ميادين مختلفة، فالجد والأب والحفيد، علماء محدَثون، وبرزوا في علوم عدة ، كان متقناً وعالماً بأيام الناس.
The insects like other creatures in the wide world, and there are more than a million class and type of these objects, some of which human haunted since the old to the present day.
In this study highlight the insect bee addressing her life and behavior, and the novelty of her and wonders what mystified by the minds of men that her world is full of mysteries and surprises drew the attention of workers in the natural history of the study and scrutiny of methods and different characteristics of scientists as she gives more than it takes. It appeared that the Islamic heritage has singled out these insects with something of interest and precise detail, but that God Almighty made suras from the Koran carrying insect name two Sura
... Show MoreAcademic Buoyancy of High School students at the Distinguished Schools
The research includes a bout IL- IQulle , and their role in scientific of the Islamic – Arabic civilization , for Dr. Khlood M.Namma the proff in the collage of education for woman , Baghdad university , History department
Toni Morrison (1931-), the first African-American winner of Noble Prize in literature (1993) and the winner of the 1988 Pulitzer Prize for fiction, regards herself as the historian of African-American people. She does not think of her writings as literature but as a sacred book dedicated to explore the interior lives of blacks. She creates history by disregarding European standards and the white man's view of African- Americans. She adopts her people's point of view, invests their heritage, voices their pains and uses their vernacular. She even writes to a black audience. She establishes the black novel by depicting the blackness of American literature. In choos
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اسلوب الحوار في القرآن الكريم اسلوب حياة وفي حقيقة الامر يضم القرآن الكريم بين دفتيه حوارات كثير مابين الله عزوجل وخلقه وما بين الانبياء واقوامهم وما بين الانبياء والطواغيت ومابين المؤمنين والكفار وهكذا ، وبدء الخلق قام على حوار مابين الله عزوجل وآدم وما بين آدم وابليس وما بيا الله جل وعلا والملائكة .