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Article
Drag Reduction of Crude Oil Flow in Pipelines Using Sodium Dodecyl Benzene Sulfonate Surfactant

Authors: Ali A. A. Hadi --- G. A. R. Rassoul
Journal: Iraqi Journal of Chemical and Petroleum Engineering المجلة العراقية للهندسة الكيمياوية وهندسة النفط ISSN: 19974884/E26180707 Year: 2007 Volume: 8 Issue: 2 Pages: 29-34
Publisher: Baghdad University جامعة بغداد

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Abstract

In the present worA a closed loop circulation system consist of three testing sections was designed and constructed. The testing sections made from (3m) of commercial carbon steel pipe of diameters (5.08, 2.54 and 1.91 cm) . Anionic surfactant (SDBS)with concentrations of (50 100, 150, 200 and 250 ppm) was tested as a drag reducing agent The additive(SDDS) studied using crude oilfrom south of Iraq. The flow rates of crude oil were used 08 and 2.54cm ID.pipes are (1 — 12) m3/hr while (1-6) ra were used in 1.91 cm ID. pipe. Percentage drag reduction (%Dr) was found to increase by increasing solution velocity, pipe diameter and additives concentration (La increasing Renolds number).Also it was found that there is no change in apparent physical properties (viscosity) of crude oil after the addition of SDBS, The higher value of drag reduction of 54% in 5 cm ID. was observed using 250 ppm SDBS surfactant dissolved in the used crude oil at flow rate of 12 m Friction factor was calculated from experimental data. The friction factors values for pure solvent lies near or at Blasius asymptote suggestedfor flow of Newtonian fluids. Afier the addition of small amount of SDI3S, the friction factor values were positioned below Blasius asymptote toward Virk maximum drag reduction asymptote, &hich was never reached.


Article
Settlement Reduction Underneath Surface Circular Footing Resting on Reinforced Soils.

Author: Hayder M. Mekkiyah
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2007 Volume: 13 Issue: 4 Pages: 1920-1933
Publisher: Baghdad University جامعة بغداد

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Abstract

An analytical approach, adopted to find the settlement of foundations resting on reinforced soil based on the test results on a model surface circular footing resting on reinforced soil, is summarized. The soil was reinforced using biaxial geomesh. The settlement was determined by considering the compatibility of strain (settlement) between soil and reinforcement element underneath the foundation. Theoretical equations were used to estimate the settlement either from the superstructure loads or from in-situ plate load tests on the reinforced soil system. The type of geomesh used in this study has been determined based on the grain size distribution of the soil. The investigation in this study used two different types of geomesh. Uniformly graded sand was used to make it easier to control the density and fabric in different tests. It was found that initial horizontal and vertical movement of the reinforcement is needed to mobilize the reinforcing strength. Further, the initial settlement at small loads could be avoided when the reinforcement was placed closer to the base of the footing and there was an improvement in the bearing capacity value of the footing. When the reinforcement is placed away from the base of the footing(greater than B), the initial settlement decreased with a slight improvement in the bearing capacity compared with that of unreinforced soil. Non-dimensional factors were developed for settlement calculations based on the experimental test results from a series of laboratory tests on the model footing. Additional tests were performed on the model footing to evaluate the effect of the number of reinforcement layers and the depth of the top most reinforcement layer on the settlement and the improvement in the bearing capacity of the footing-reinforced soil system.

اقترح في هذه الدراسة تحليل الهبوط تحت الاسس المسلحة ترابيا مبنيا على تجارب الفحوص المختبرية لهذه الأسس الجالسة على التربة المسلحة حيث أن التربة تم تسليحها بواسطة قطع ( شبكة) تسليح بلاستيكية. كان مبدأ التحليل مستندا إلى التوافق في الانفعال الحاصل تحت الأسس لكل من التربة وقطع التسليح.أن المعادلات المقترحة لحساب الهبوط تحت هذا النوع من الأسس يمكن استخدامها لكل من نتائج الفحوصات الحقلية أو أية أحمال متوقعة من المنشأ يراد حساب الهبوط تحتها ،تم استخدام رمل منتظم متدرج في هذه الفحوص .لوحظ من أجل حصول حركة (رأسية / أو أفقية) تحت الأسس المسلحة فلابد من وجود أحمال أكبر من تلك المقارنة بالأسس غير المسلحة ، وأكثر من ذلك أن هذا الهبوط الأولي تحت هذه الأسس يمكن إهماله عندما قيم الأحمال الأولية المسلطة قليلة وشرائح قطع التسليح قريبة من قاعدة الأسس كما لوحظ أيضا تحسن كبيرفي تحمل الأسس لهذه الحالة من التحميل ، في حين أن هناك تحسن أقل سعة التحمل عندما تكون هذه الشرائح بعيدة عن الأسس وفي المقابل الهبوط المتوقع يكون أكبر ،أن مثل هذا التباين في مقدار الهبوط لمثل هذه الحالات من التحميل تم أخذه بعين الاعتبار حينما تم وضع المعاملات اللابعدية من أجل حساب الهبوط المتوقع تحت الأسس في المعادلات المقترحة في هذه الدراسة.تم حساب الهبوط لحالات فحص أخرى غير تلك التي أجريت في البحث للتأكد من مقدار الهبوط المتوقع فكان مقدار هذا الهبوط يتناسب وطبيعة التربة ومقدار الأحمال المسلطة على هذه الحالة.

Keywords

Settlement --- Circular --- Footing --- reinforced --- Soil --- Reduction

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