Print ISSN: 1813-162X

Online ISSN: 2312-7589

Volume 15, Issue 3

Volume 15, Issue 3, Summer 2008, Page 1-103


ENHANCEMENT OF PHENOL REMOVAL EFFICIENCY IN DORA REFINERY WASTEWATER TREATMENT PLANT

Dr. Salah F. Sharif

Tikrit Journal of Engineering Sciences, Volume 15, Issue 3, Pages 18-37

Because the sanctions imposed on Iraq by the United Nations, programmed maintenance and wearing parts replacement has not been performed according to schedules in DORA Refinery Wastewater Unit, which resulted in higher phenol content and BOD5 in effluents disposed to river. The investigations showed that two main reasons were behind this problem: Firstly, increased emissions of hydrocarbons in the complexity of refinery equipment and Secondly, the decreased efficiency of the aerators in the biological. During the last few months, phenol average concentration in the effluent, after biological treatment was found to be between 0.06-0.13 mg/L, while COD was exceeding 110 mg/L after treatment in the same period. Considerable enhancement, has been indicated recently, after the following performances: First: Recycling wastewater from some heat exchangers, and the segregation of low and high strength of wastewaters, Second: Minimizing emissions of hydrocarbons from fluid catalytic cracking and steam cracking, Third: Replacement of driving motors of the aerators in the biological treatment unit. After replacement of these units, a significant decrease in phenol concentration was obtained in purified water (0.03-0.05) mg/L and COD of 60 mg/L before the tertiary treatment. It is concluded that a better quality of effluents has been obtained after a series of emissions control and wastewater treatment unit equipment maintenance performances. KEYWORDSWaste water, aerator, phenolic compounds

STABILITY ANALYSIS AND DESIGN OF PRESSURE CONTROL SYSTEM

Aziz Abdul-Karim; Dr. Salam K. Hassan; Dr. Duraid Fadhel Ahmed

Tikrit Journal of Engineering Sciences, Volume 15, Issue 3, Pages 64-76

The performance of pressure control system and stability analysis was studied for different types of controllers. A theoretical model for closed-loop system is developed and dynamic behavior of the control system was studied by introducing a step change in the pressure of the inlet stream. The results show that the theoretical response is faster than the experimental response due to the lags of the control valve and measuring elements. The pressure control system is stable for all conditions and for different control action because the real parts of roots of characteristics equation are negative but the response at PID controller is oscillatory stable. when PID controller used the response is improve due to eliminate the offset and stabilizing effect of derivative allow the proportional gain to be increased and increasing the speed of response compared to proportional and proportional-integral controllers. KEYWORDS: Pressure Control, Stability, PID Control.

COMPUTER BASED HEART PULSES MEASUREMENT

Zaid H. Al-Sawaff; Thaker N. Yahya; Ali N. Hamoodi

Tikrit Journal of Engineering Sciences, Volume 15, Issue 3, Pages 94-103

In this work the measurement and displays of blood oxygen saturation and pulse rate are investigated practically using computer.The analysis involves the variation in blood oxygen saturation ratio and pulse rate. The results obtained are compared with kontron pulse oximeter 7840 device. The value obtained for the same person pulse rate is approximately equal to that obtained by the konton pulse oximeter 7840 device. The sensor used in this work is the finger clip.The advantages of using computer over kontron pulse oximeter 7840 device is that the data of the patient can be saved in the computer for many years and also it can be display at any time so that the doctor get file contains all data for each patient.KEYWORDS: Blood Oxygen Saturation, Pulse rate, Interface, Finger sensor

A STUDY OF PHASE EQUILIBRIUM OF H2S IN SEVERAL PHYSICAL SOLVENTS USING CHEMCAD SIMULATOR

Dr. Zaid A. Abdel-Rahman

Tikrit Journal of Engineering Sciences, Volume 15, Issue 3, Pages 38-48

CHEMCAD process simulator was used for the analysis of the literature experimental phase equilibrium data of H2S with three physical solvents (Sulfolane, Propylene Carbonate (PC), and N-Methyl-2-Pyrrolidone (NMP)) at different temperatures ( 298.15 oK , 323.15 oK, and 373.15 oK). Two thermodynamic models, Peng-Robinson (PR) and Soave-Redlich-Kwong (SRK), were used.The equilibrium data of H2S- Sulfolane and H2S- Propylene Carbonate (PC) systems were successfully correlated using SRK thermodynamic model. The deviation was noticed only for H2S-Sulfolane system as the temperature increases to 373 oK, to give a deviation of less than 5% .The thermodynamic models used in present study, PR, and SRK , built in CHEMCAD simulator and used as such without modification, fail to correlate the equilibrium data of H2S- NMP (N-Methyl-2-Pyrrolidone) system for all temperature range used. Modifications of the thermodynamic models were performed by editing user defined binary interaction parameters (BIP) of the systems used, gives good results.KEYWORDSVapor–Liquid Equilibria, H2S, Physical Solvents, CHEMCAD Simulator, Thermodynamic Models, Equation of state and correlation

MESH SIZE EFFECTS IN NONLINEAR DYNAMIC 3D-ANALYSIS OF REINFORCED CONCRETE BEAM UNDER IMPACT LOADS

Tikrit Journal of Engineering Sciences, Volume 15, Issue 3, Pages 77-93

The investigation into the effect of mesh size in nonlinear 3D-analysis of reinforced concrete beam under dynamic load presents in this paper. The behavior of reinforced concrete beam under dynamic loads are supported by intensive numerical simulations, and the effect of various parameters on the results is of great interest. Finite element simulations were performed in the nonlinear dynamic domain with modified concrete and steel constitutive models. To eliminate the dependence of the computed results on the mesh size, a procedure for calculating the ultimate tensile strain of concrete was developed and implemented into nonlinear dynamic analysis. The proposed model gives good agreement with the experimental results. In particular, the new model can be used effectively with relatively mesh size in reasonable accuracy.

ECONOMICAL DESIGN OF CIRCULAR FOOTINGS ADJACENT TO SLOPES ON SANDY SOILS

Tikrit Journal of Engineering Sciences, Volume 15, Issue 3, Pages 49-63

The analysis presented here introduces three optimization techniques namely, Hooke and Jeeves, Fletcher-Reeves and Davidon-Fletcher-Powell as applied to design of the circular footing adjacent to slopes. A computer program was developed to solve this design problem using the conventional structural design approach in conjunction with these methods, A simple study was performed to detect the sensitivity of the objective function to its design variables. A further parametric study was performed regarding the geometric configurations of the footing and loading conditions in order to provide the geotechnical engineer with some useful design curves. Hooke and Jeeves method has been proved to be very instructive in exposing the effect of the other methods.It has been proved that the minimum cost of the circular footing increases with the increase of the load whereas it decreases as the angle of internal friction increases and the Dcl/B ratio (column diameter/diameter of footing). Key words: optimization, conventional design, slope, circular footing, sandy soil.

DRAG FORCES AND FLOW TYPES ON UNCONVENTIONAL TYPES OF STILLING BASINS BAFFLE BLOCKS

Tikrit Journal of Engineering Sciences, Volume 15, Issue 3, Pages 1-16

إن الهدف من الدراسة الحالية هو إيجاد معامل السحب وتوزيع الضغوط مع بيان أنماط الجريان على أنواع غير تقليدية من الكتل الكابحة المقطوعة بزوايا منتخبة أفقية وعمودية ونصف اسطوانية ومقارنة النتائج مع الكتل الكابحة القياسية (شبه المنحرفة)، وقد استخدم البرنامج الحاسوبي (Fluent) والنتائج المختبرية لتحقيق هذا الهدف. وقد تم الحصول على قيم معامل السحب لمختلف الكتل الكابحة المستخدمة في الدراسة بدلالة رقم فرود الابتدائي وبينت النتائج إن معامل السحب للكتل المقطوعة عموديا" هو اقل من معامل السحب للكتل المقطوعة أفقيا" ولنفس ظروف الجريان. إضافة إلى إن القيم القصوى للضغوط المسلطة على أسطح النماذج المقطوعة عموديا اقل نسبيا من بقية النماذج، لذا فأن استخدام هذه النماذج من الناحية الإنشائية سوف يكون أفضل من البقية.

INTELLIGENT SYSTEM TO EVALUATE THE NEIGHBORHOOD UNIT CRITERIA

Tikrit Journal of Engineering Sciences, Volume 15, Issue 3, Pages 17-25

أن من التوجهات الحديثة لتخطيط المدن هو أن يتم تخطيطها وفق تدرج هرمي من المستويات يبدأ من المحلة السكنية و انتهاءا بالقطاع السكني بواسطة استخدام مؤشرات رقمية وغير رقمية يرجع لها المصمم الحضري عند التخطيط وهي المعايير التخطيطية التي تنظم ذلك التدرج . تم في هذا البحث تناول تلك المعايير ضمن مستوى المحلة السكنية و أنواعها وكيفية احتسابها بالرجوع إلى الأدبيات ثم تقييم المعايير التخطيطية الموجودة ضمن ثلاث محلات سكنية مصممة عن طريق بناء نظام حاسوبي ذكي تم تصميمه من قبل الباحثتين لمعرفة كفاءة التصميم وتحديثه بين التصاميم الثلاث للتوصل الى النتائج .وكانت فرضية البحث هي ان كفاءة تصميم المحلة السكنية يعتمد على المعايير التخطيطية لعناصر المحلة السكنية، وكان هدف البحث هو في استحداث نظام حاسوبي ذكي لتقييم المعايير التخطيطية للمحلات السكنية المصممة وإمكانية تحديثها كلما تطلب ذلك .

GEOMETRIC AND MATERIAL NONLINEAR ANALYSIS OF REINFORCED CONCRETE SLABS AT FIRE ENVIRONMENT

Dr. Ayad A. Abdul -Razzak

Tikrit Journal of Engineering Sciences, Volume 15, Issue 3, Pages 1-17

In the present study a nonlinear finite element analysis is presented to predict the fire resistance of reinforced concrete slabs at fire environment. An eight node layered degenerated shell element utilizing Mindlin/Reissner thick plate theory is employed. The proposed model considered cracking, crushing and yielding of concrete and steel at elevated temperatures. The layered approach is used to represent the steel reinforcement and discretize the concrete slab through the thickness. The reinforcement steel is represented as a smeared layer of equivalent thickness with uniaxial strength and rigidity properties.Geometric nonlinear analysis may play an important role in the behavior of reinforced concrete slabs at high temperature. Geometrical nonlinearity in the layered approach is considered in the mathematical model, which is based on the total Lagrangian approach taking into account Von Karman assumptions.Finally two examples for which experimental results are available are analyzed, using the proposed model .The comparison showed good agreement with experimental results.KEYWORDS: Fire resistance, Material and Geometrical nonlinearity, Reinforced Concrete Slabs