Influence of combined square nozzle with helical tape inserted in a constant heat flux tube on heat transfer enhancement for turbulent airflow for Reynolds number ranging from 7000 to 14500 were investigated experimentally. Three different pitch ratios for square nozzle (PR = 5.8, 7.7 and 11.6) according to three different numbers of square nozzle (N = 3, 4 and 5) and constant pitch ratios for helical tape were used. The results observed that the Nusselt number and friction factor for combination with winglets were found to be up to 33.8 % and 21.4 %, respectively higher than nozzle alone for pitch ratio PR=5.8. The maximum value of thermal performance for using combination with winglets was about 1.351 for pitch ratio= 5.8. Nusselt number and friction factor correlations from experimental data were developed for turbulent flow.
This research studies the effect of adding micro, nano and hybrid by ratio (1:1) of (Al2O3,TiO2) to epoxy resin on thermal conductivity before and after immersion in HCl acid for (14 day) with normality (0.3 N) at weight fraction (0.02, 0.04, 0.06, 0.08) and thickness (6mm). The results of thermal conductivity reveled that epoxy reinforced by (Al2O3) and mixture (TiO2+Al2O3) increases with increasing the weight fraction, but the thermal conductivity (k) a values for micro and Nano (TiO2) decrease with increasing the weight fraction of reinforced, while the immersion in acidic solution (HCl) that the (k) values after immersion more than the value in before immersion.
Many production companies suffers from big losses because of high production cost and low profits for several reasons, including raw materials high prices and no taxes impose on imported goods also consumer protection law deactivation and national product and customs law, so most of consumers buy imported goods because it is characterized by modern specifications and low prices.
The production company also suffers from uncertainty in the cost, volume of production, sales, and availability of raw materials and workers number because they vary according to the seasons of the year.
I had adopted in this research fuzzy linear program model with fuzzy figures
... Show MoreIn this work laser detection and tracking system (LDTS) is designed and implemented using a fuzzy logic controller (FLC). A 5 mW He-Ne laser system and an array of nine PN photodiodes are used in the detection system. The FLC is simulated using MATLAB package and the result is stored in a lock up table to use it in the real time operation of the system. The results give a good system response in the target detection and tracking in the real time operation.
Phoenix dactylifera l. pinnae (the green leaves of dates palm) were used as natural reinforcing (strengthening) fibers to improve the mechanical properties of polyester as a matrix material, the fibers of the green leaves of dates palm were used in two lengths, 10 and 20mm with five rates of 0, 2.5, 5, 10, and 20% , where the reinforcing with the leaves fibers increases the hardness strength from 76.5 to be about 86.55 , the Impact value raised from about 0.313 to 0.461 , in addition to that the flexural strength from 2.66 to be about 55 , and the thermal conductivity increases from 2.54 𝑤∕𝑚.℃ to 5.41 𝑤∕𝑚.℃. The results of the present search explains that the composite samples reinforced at rate 20% and 10mm fiber length
... Show MoreIn this paper, we used two monomers, 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA) and m,m'-diaminobenzophenone (m, m’-DABP), to produce polyamide acid and then converted it to polyimide (PI). The effects of phosphoric acid (H3PO4) molarity (1, 2, and 3 M) on the structural, thermal, mechanical, and electrical characteristics of the polyimides/polyaniline (PI/PANI) nanocomposites were studied. Two sharp reflection peaks were developed by the addition of PANI to PI. When 3 M H3PO4 is added, the crystalline sharp peak loses some of its intensity. The complex formation of PI/PANI-H3PO4 was confi
... Show MoreThe objective of the present study is to determine the effect of Kaolin as a fuel oil additive to minimize the fireside corrosion of superheater boiler tubes of ASTM designation (A213-T22) by increasing the melting point of the formed slag on the outside tubes surface, through the formation of new compounds with protective properties to the metal surface. The study included measuring corrosion rates at different temperatures with and without additive use with various periods of time, through crucible test method and weight loss technique.
A mathematical model represents the relation between corrosion rate and the studied variables, is obtained using statistical regression analysis. Using this model,
... Show MoreIn today's cities, it is easy to see large numbers of vacant lands and unused abandoned sites in downtown areas that are not only ugly but also potentially becoming fertile ground for criminal activities that endanger residents and visitors and contribute to the further degradation of neighborhoods,
can provide reuse of spaces Neglected opportunities to reshape the appearance of the city and to improve the city center for its users that the presence of many neglected sites, whether they were abandoned buildings or sites for destroyed buildings in Mosul after the war on ISIS and with large areas amid the urban fabric led to the emergence of the research problem is (lack of urban planning to reactivate abandoned sites within the ci
... Show Moreيعتبر الخزين من الامور الهامة في العديد من الشركات حيث يمثل نسبة 50 % من رأس مال المستثمر الكلي مع شدة الضغط المتمثل الى خفض التكاليف الكلية المتمثلة مع انواع اخرى من حالات عدم التأكد (الضبابية) لذا سوف نقدم في هذا البحث نظام اقتصادي للكميات الكلية ( الانتاج الاقتصادي للكميات) للوصول حجم الدفعة المثلى المضببة (FEOQ) عندما تكون كل المعالم في حالة عدم التأكد حيث يتم تحويلها الى فترة واحدة وبعد ذلك الحصول على حجم الد
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