البحث — المستودع الرقمي العراقي

المستخلص: In the oil and gas industry, the crude oil pipelines which made of low carbon steel suffer from internal corrosion. The corrosion operation is originally related with the presence of the wastewater mixed with the crude oil, especially when it is accompanied by hydrogen sulfide, carbon dioxide, elemental sulfur, inorganic salts, organic acids, and bacteria. Corrosion inhibitors injection in the oilfield is a most common and beneficial method for prevention the pipelines internal corrosion. Because of a high cost and toxic nature of the chemical corrosion inhibitors which used presently in oil industry, it is necessary to promote a less expensive and environmentally acceptable inhibitors, natural plants can be treated as a perfect sources for this purpose.This study investigate the internal corrosion of low carbon steel pipelines in fluid environments, as well as prepare and use natural and locally available plant ( the bark of eucalyptus tree) as a natural corrosion inhibitor, and compared the new inhibitor with a chemical inhibitor used by Missan Oil Company (MOC) in terms of the cost, toxicity, availability and performance.Some experiments were achieved to estimate the performance of a new inhibitor, one of these tests include corrosion measurement by simple immersion in crude oil within and without of inhibitors which added in different amounts 30, 40, 50, and 60 ppm , where the best inhibition efficiencies which get when added the inhibitors in a critical amounts or closest to it, since for the aqueous extract (EB - A) the inhibition efficiency reached (94.4) and (86.71)% at 300 and 323K respectively, and for diethyl ether extract (EB - D) reached (82.87) and (84.6)% at 300 and 323K respectively, while the chemical inhibitor (CRW) which used by MOC reach to (84.21) and (88.73)% at 300 and 323K respectively.optical microscopy examination have been conducted to evaluate the corrosion nature where it show a clear difference in the topography of the immersed samples surface after add the inhibitors at two temperatures.Another tests was achieved to evaluate the corrosion behavior such as potentiostatic polarization and open circuit potential tests in wastewater, since the inhibitor efficiency at 313k reached (88.21)% when add a 60ppm from the EB - A inhibitor to the wastewater in Tafel extrapolation, while it reached (74.91)% when add a 30ppm from the EB - D inhibitor.Several tests was achieved such as FT - IR spectra and using a chemical reagents to detection the presence of many active groups and the presence of tannins, phenols and alkaloids in the Eucalyptus Bark (EB).The results show , that the new corrosion inhibitor is not only equivalent to a chemical inhibitor, but have greatly improvement properties such as : high efficiency , low cost , non - toxic , easily to product, and nonpolluting as compared with chemical inhibitor which is considered toxic and cancering inhibitor.

استقصاء الخواص الفيزيائية والميكانيكية لنحاس الومينا متدرج وظيفيا == Investigation Of Physical And Mechanical Properties Of Cu/Al2O3 Functionally Graded Materials

اسم المؤلف: رؤى حاتم كاظم

اسم المشرف: عبد الرحمن كاظم عبد علي

الموضوع العام: هندسة الانتاج والمعادن والمواد

السنة: 2017

الموضوع الدقيق: هندسة المعادن

الدرجة: ماجستير

الجامعة: جامعة بابل - كلية هندسة المواد - قسم هندسة المعادن

اللغة: الانكليزية

مكان الجامعة: بابل

الصفحات الاولى:

المستخلص: One of the most important smart material is the functionally graded materials, which had more increasing attention in different engineering applications.In this study, five - layered stepwise Cu/Al2O3 as functionally graded materials have been prepared from copper powder with five percentage of alumina powder as (5, 10, 20, 30, and 40 Wt%) by using powder metallurgy technique. Mixing of copper (34.32 ?m) and alumina (1.439 ?m) powders for two hours and then several disk sample with dimensions (14mm diameter and 10mm thickness) and cylindrical specimens with (18mm diameter and 27 height) have been compacting at different compacting stresses (550, 650 and 750 MPa). However, sintering of specimens for three hours at 850?C under vacuum about has been achieved.Several physical tests such as porosity, electrical resistance and thermal conductivity, X - ray diffraction, X - ray Fluorescence and Particale size analysis have been achieved. Furthermore, Microstructure and mechanical tests such as hardness, compression, double shear and dry sliding wear have been done for preparing samples from composite and functionally graded material.Numerical modeling using finite element analysis by ANSYS software has been presented for copper/alumina joints and compare with copper/alumina functionally graded materials.From the several experimental results, it is clear that the best compacting pressure was 650 MPa is determined by measuring green density at different compacting pressure, hardness increased with the increasing additive percentage of alumina, hardness resultschange in each layer by producing functionally graded materials (FGM) according to the percentage of the harder constituent (i.e. Al2O3) from 53 to 113 HV at compacting pressure 650 MPa, While the shear strength decreases with alumina increased from 72 MPa for layer one to 28 MPa for layer five at compacting pressure 650 MPa. The Wear rate increases as the time and load is increased. The wear resistance increased with increasing contain of Alumina. Results from the numerical modeling, it is clear that residual thermal stresses gradually decreased from the interface to the edges of functionally graded sample whereas in Copper/Alumina joint there is very high thermal residual stress in the joint interface.

امثلية عمليات اللحام باستخدام مصفوفة التضارب == Optimization Of Welding Processes Using Confusion Matrix

اسم المؤلف: حسين خليل برهان

اسم المشرف: حيدر الجبوري