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.
Education received the attention of the monarchy in Iraq, especially after the developments that the country witnessed after Iraq gained independence and joined the League of Nations in 1932 AD in all political, economic and cultural aspects. In this regard, due to its distinguished geographical location, where the atmosphere, the natural environment and the religious and political standing were available, which made it a center of attraction for most Iraqi families and political figures.
يهدف البحث التعرف على مستوى الوعي بتقنيات إعادة التدوير غير الميكانيكية التي يجري تطويرها حاليًا في قطاع "إعادة التدوير الكيميائي" الجديد لدى طلبة كلية التربية للعلوم الصرفة -ابن الهيثم. تكونت عينة البحث من (198) طالبا وطالبة من قسم الكيمياء للعام الدراسي (2021-2022) من أصل(250) أي (79%) من مجتمع البحث لدراسة الفصول الصباحية و(50) طالباً وطالبة من أصل (73) أي (68٪) من مجتمع البحث لدراسة الفصول المسائية لطلبة المرحلة الرابعة.وت
... Show Moreهدف هذا البحث الى استعمال الأسلوب الرياضي أسلوب التحليل الهرمي وتطبيقه وفق ابعاد بطاقة الاداء المتوازن في تقييم الأداء الاستراتيجي في الهيئة العامة للأثار والتراث، وتمثلت أدوات البحث باستعمال استمارات التحليل الهرمي وطبقت على معايير بطاقة الأداء المتوازن المتمثلة في (المالي، الزبائن، العمليات الداخلية، والتعلم والنمو)، وتم استهداف عينة قصدية متمثلة في رئيس الهيئة والمدراء العامون بعض من مدراء الأقسام ال
... Show MoreA seemingly uncorrelated regression (SUR) model is a special case of multivariate models, in which the error terms in these equations are contemporaneously related. The method estimator (GLS) is efficient because it takes into account the covariance structure of errors, but it is also very sensitive to outliers. The robust SUR estimator can dealing outliers. We propose two robust methods for calculating the estimator, which are (S-Estimations, and FastSUR). We find that it significantly improved the quality of SUR model estimates. In addition, the results gave the FastSUR method superiority over the S method in dealing with outliers contained in the data set, as it has lower (MSE and RMSE) and higher (R-Squared and R-Square Adjus
... Show MoreWater resources would be differentiate in Morocco specially in Morocco which appear as form of eyes ,rivers as dissolved water of mountain.
The human takes care of water either as rains to store and use in necessity trying to bring it to Maracas by helping from state .
The religious tried to dig wells to emphasize that water is rumored and do not monopolized.
هدف البحث إعداد تدريبات تزامن ما بين السايكو وتمرينات القوة الوظيفية للاعبي كرة القدم، والتعرف على تأثيرها في القدرة الانفجارية للرجلين، وفي مهارتي المناولة الطويلة والركلة الركنية للاعبي كرة القدم، ليفترض الباحث بإنه توجد فروق ذات دلالة إحصائية بين نتائج الاختبارات القبلية والبعدية لمجموعتي البحث التجريبية والضابطة في كل من القدرة الانفجارية للرجلين لمهارتي المناولة الطويلة والركلة الركنية في كرة القد
... Show Morehe is one of the most prominent Arab personalities who contributed in the Arab Muslim world, scholars and historians who appeared in the seventh century AH - the thirteenth century AD, contributed to enrich the Arab scientific heritage in his distinguished book “The Wonders of Creatures and the Strangeness of Existences” because it contained what God Almighty created and the oddities on dry land and water
It has became necessary helping the children to developing same of educational values which can be drawn from daily situations which the live. Especially the childhood stage is the basic building of value individual content since its establishment the societies take care of learning children and take care of them. Through their institutes which depended on, in this function. Therefore the importance of this, research is coming from the importance of this age stage and from importance and necessity of children aguirement the educational values and its development to them, and the importance this research coming from depending on guidance program with new content and it is (al bum of pictures) fro
... Show MoreThis study discussed a biased estimator of the Negative Binomial Regression model known as (Liu Estimator), This estimate was used to reduce variance and overcome the problem Multicollinearity between explanatory variables, Some estimates were used such as Ridge Regression and Maximum Likelihood Estimators, This research aims at the theoretical comparisons between the new estimator (Liu Estimator) and the estimators