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تطبيقات الطرق العددية في التاكل الكلفاني للمعادن المزدوجة == Applications of Numerical Methods In Galvanic Corrosion of Coupled Metals

اسم المؤلف: بسمة محمد كاظم الشاهر

اسم المشرف: جمال مانع علي الربيعي

الموضوع العام: الهندسة الكيمياوية

السنة: 2014

الموضوع الدقيق: العمليات الصناعية

الدرجة: ماجستير

الجامعة: الجامعة التكنولوجية - قسم الهندسة الكيمياوية

اللغة: الانكليزية

مكان الجامعة: بغداد

الصفحات الاولى:

المستخلص: تم دراسة سلوك تاكل معادن النحاس والكربون الصلب والزنك في تراكيز مختلفة من حامض الهيدروكلوريكHCl) ) (0.025، 0.05 و0.075 مولاري ) عند درجات حرارة مختلفة (30، 40 و50 درجة مئوية) باستخدام القياسات الكهروكيميائية (Electrochemical Measurements) في حالة المعا | The corrosion behaviors of metals Copper, Carbon Steel and Zinc in a different concentrations of HCl acid (0.025, 0.05 and 0.075M) at different temperatures (30, 40 and 50°C) were investigated using electrochemical measurements in couple and single state.The galvanic behaviors of coupled metals (Cu - Fe),( Cu - Zn) and (Fe - Zn)were studied using Zero Resistance Ammeter (ZRA) technique, it has been used to measure the galvanic current (Ig) and galvanic potential (Eg) with time. The galvanic corrosion cells for all couples have equal areas of anode and cathode (2×2cm).The galvanic current density (ig) is increased with increasing solution concentration and temperature. The galvanic potential (Eg) is shifted to less negative with increasing solution concentration and temperature and it is close to the corrosion potential of the anode in the couple conditions.The potentiostatic polarization behavior of single three metals (Copper, Carbon Steel and Zinc) in different concentrations of dilute HCl acid (0.025, 0.05 and 0.075M) at temperature (40°C) is found under activation control. The corrosion current density is increases with increasing solution concentration and gives the following arrangement of metals : Cu> Fe > Zn A numerical analysis of galvanic corrosion was presented. The analysis was based on three numerical methods as the boundary element method (BEM), the finite element method (FEM) and the finite difference method (FDM).The potential and current density distributions on the galvanic elements are described by the Laplace equation. The Laplace equation was solved numerically, to determine the potential, current density, and corrosion caused by the galvanic cell using designed computer programs in MATLAB R2014a. The experimentally determined polarization curves have been used in order to define the nonlinear boundary conditions. This boundary value problem has been solved using Newton - Raphson iterative numerical procedure. For the three couple systems (Cu - Fe, Fe - Zn and Cu - Zn), the results obtained for galvanic potential and current density, using the numerical methods (BEM, FEM and FDM) with the overall deviations are 6.689, 10.818 and 18.846 respectively for galvanic current density and 0.631, 1.210 and 1.787 respectively for galvanic potential. From these results it can conclude that the galvanic current density and galvanic potential distribution calculated from the BEM model was in good agreement with the experimental measurements. These are because the main advantages of the BEM over the Finite Element Method (FEM) and the finite difference method (FDM) are high accuracy, discretization on the boundary only which results in a very small number of unknowns, easy dealing with non - regular boundaries and openings that only the domain boundary of interest is required to be discrete, also BEM needs fewer equations and a smaller matrix size than FEM and can solve both finite and infinite domain problems.

استخلاص الزيوت العطرية من قشور الحمضيات باستعمال التقطير البخاري بمساعدة المايكرويف == Extraction of Essential Oils From Citrus By - Products Using Microwave Steam Distillation

اسم المؤلف: سارة جبير صالح

اسم المشرف: ابتهال كريم شاكر

الموضوع العام: الهندسة الكيمياوية

السنة: 2014

الموضوع الدقيق: الهندسة الكيمياوية

الدرجة: ماجستير

الجامعة: جامعة بغداد - كلية الهندسة - قسم الهندسة الكيمياوية

اللغة: الانكليزية

مكان الجامعة: بغداد

الصفحات الاولى:

المستخلص: يهدف هذا البحث الى استخلاص الزيت العطري من ثلاثة انواع من قشور الحمضيات (البرتقال, الليمون, اللالنكي) بطريقتين : التقطير البخاري والتقطير البخاري بمساعدة المايكرويف.ودراسة تاثير عوامل الاستخلاص : (وزن القشور, وقت الاستخلاص,طاقة المايكرويف ونوع قشور الحمضي | The main objectives of this research is to extract essential oil from : orange( citrus sinensis), lemon( citrus limon) and mandarin( citrus reticulata) peels by two methods : steam distillation (SD) and microwave assisted steam distillation (MASD), study the effect of extraction conditions : weight of the sample( 398.56g, 281.8g, 116.76g), extraction time, microwave power( 135W, 265W, 445W) and citrus peel type( orange, lemon, mandarin) on oil yield and compare the results of the two methods, the resulting essential oil was analyzed by Gas Chromatography (GC).Essential oils are highly concentrated substances used for their flavor and therapeutic or odoriferous properties, in a wide selection of products such as foods, medicines and cosmetics. Extraction of essential oil is one of the most time and effort consuming process. Microwave - assisted extraction is a green technique for the extraction of natural products. (MASD) was better than (SD) in terms of rapidity, energy saving and yield. (MASD) gave higher yield than (SD) with shorter extraction time, yield of orange oil extracted by (MASD) was (1.150%) in (35min.) compared to (1.095%) in (45min.) by (SD) process, same results obtained for lemon and mandarin. It was found that the optimal microwave power was (135W) and the yield was : (1.150%, 1.115%, 0.940%) for orange, lemon and mandarin respectively, (MASD) increased extraction temperature in short time and to a higher level compared to (SD).It was found that the optimal weight was (398.56g) and the yield in (SD) was : (1.095%) and MASD (1.091%) for orange oil, same results obtained for lemon and mandarin.The best citrus peel type which gave the highest yield was orange followed by lemon then mandarin in both processes.Limonene is the most abundant component in citrus essential oil, (GC) analysis showed that the amount of limonene increased in low microwave power with long extraction time for mandarin oil it was (84.3891% at 135W in 60min.), while for (SD) it was (83.0271% in 75min.) and decreased with increasing microwave power for orange oil it was (80.9661% at 265W in 35min.) while for (SD) it was (83.2189% in 45min.), (SD) was more convenient to give high amount of limonene because of the graduate temperature rise, while in microwave extraction exposure to low microwave power for long time would give complete recovery and better quality of essential oil.

تاثير الحماية من التاكل بواسطة الليزر على سبائك الالمنيوم == The Effect of Laser Surface Melting Corrosion Protection On Al Alloys

اسم المؤلف: هبة خميس اسماعيل

اسم المشرف: شذى احمد سامح

الموضوع العام: الهندسة الكيمياوية

السنة: 2014

الموضوع الدقيق: الهندسة الكيمياوية

الدرجة: ماجستير

الجامعة: الجامعة التكنولوجية - قسم الهندسة الكيمياوية

اللغة: الانكليزية

مكان الجامعة: بغداد

الصفحات الاولى:

المستخلص: يهدف هذا البحث الى دراسة تاثير المعاملة بالليزر على تاكل سبائك الالومنيوم (7075, 6061, 5083) المغمورة في محلول ملحي (كلوريد الصوديوم) بمختلف التراكيز. وقد تم اعداد عينات من سبائك الالومنيوم ذات ابعاد (2 ملم) سمك وقطر (25 ملم)، وكانت تجارب الاستقطاب في مح | The objectives of the present project are to generate uniform melted layers, free of large second phases to assess the corrosion resistance of the laser treated surface in comparison with the untreated alloy. So disc samples of (7075, 6061 and 5083) aluminum alloys of 2 mm thickness and 25 mm diameter, have been prepared. Polarization tests were carried out in (M lab potentiostat / galvanostat) (Germany) at 298K temperature and (1.5, 2.5 and 3.5) % wt of NaCl solution. The experiments were carried out before and after laser surface melting by (Nd : YAG, MED - 810) pulse laser, system (Q - Switched Nd : YAG 1064/532nm). Before laser surface melting the results showed that the value of the corrosion current density obviously increases with increasing the concentration of NaCl from 1.5% to 3.5%. As well as higher Cl - ions concentration more negative pitting potential (Epit) of aluminum alloys and decrease in the electrochemical stability of aluminum. The corrosion rate for the specimen 7075 is larger than that of 6061 and 5083 aluminum alloys under the same conditions. So it means that the specimens 6061 and 5083 have high resistance to corrosion in NaCl solution After laser surface melting the results showed that the surface of aluminum alloys became more homogenous and pure after treatment.It was found that the corrosion current density decreases after Laser Surface melting at about three orders than that of untreated samples, therefore, the value of the corrosion rate of laser - treated alloy is smaller than that of the untreated. As well as the pitting corrosion potential after Laser Surface melting obviously shifted to more positive direction for all aluminum alloys in different concentrations of the NaCl solution.

تطبيق اللابفيو والخوارزمية الوراثية في السيطرة على مبادل حراري من نوع الصفائح == Application of LabVIEW And Genetic Algorithm For Controlling of Plate Heat Exchanger

اسم المؤلف: ايمن فوزي زوين

اسم المشرف: زيدون محسن شكور

الموضوع العام: الهندسة الكيمياوية

السنة: 2014

الموضوع الدقيق: تكرير النفط وتقنيات الغاز

الدرجة: ماجستير

الجامعة: الجامعة التكنولوجية - قسم الهندسة الكيمياوية - فرع الهندسة الكيمياوية وتكرير النفط

اللغة: الانكليزية

مكان الجامعة: بغداد

الصفحات الاولى:

المستخلص: تم دراسة السلوك الديناميكي لمبادل حراري من نوع الصفائح ( يتكون من 24 صفيحة ) والسيطرة عليه. الموديل النظري للمبادل طور بالاستناد على الموازنة الحرارية لصفائح المبادل.نتائج الموديل توضح السلوك الديناميكي للمبادل حيث تبين انه من الدرجة الاولى بالتقديم ((le | In this work the dynamic behavior of a plate heat exchanger (PHE) (consists of 24 plates) both experimentally and theoretically and the control of the system were studied. A theoretical model for the plate heat exchanger was developed based on the heat balance. A step change is carried in the hot water flow which is considered as a manipulated variable.The results of plate heat exchanger (PHE) showed that the dynamic behavior of plate heat exchanger in this work is dynamically as a first order lead and second order overdamped lag with a significant delay time as shown below : G(p)=(T ?_co (s))/(m ?_h (s) )= ((0.2645s+1.411) e^( - 5.63s))/(0.2156s^2+12.34s+1) The experimental heat transfer measurements of the plate heat exchanger (PHE) indicated that the overall heat transfer coefficient (U) is related to the water flow rate (m) by a correlation having the form : U = 10637 m0.7307 To verify the presented model, temperature control was applied theoretically and experimentally to the plate heat exchanger using conventional P, PI and PID controllers with tuning of control parameters by different methods; Ziegler - Nichols, Cohen - Coon and genetic algorithm to find the best values of proportional gain (Kc), integral time (?I) and derivative time (?D). The time domain specifications like rise time, settling time, overshoot and the performance indices, Integral Squared Error (ISE) and Integrated Time - Weighted Absolute Error (ITAE) were used to evaluate the performance of different control strategies. The PID controller gave better control results of temperature than other controllers, while Ziegler - Nichols tuning method gave better control results than Cohen - Coon. GA technique is the best method in simulation by compare with Cohen - Coon and Ziegler - Nichols methods. Therefore, GA method is suitable as best technique for systems which have shorter constant time.Cohen - Coon and Ziegler - Nichols methods were used in the experimental work to calculate the controller parameters, while GA method was not used in this stage.