Tikrit Journal of Engineering Sciences

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.

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.

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.

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).

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.

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.

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.

The aim of the present study is to indicate the drag coefficient, pressure distribution and flow types on unconventional types of angularly cutted baffle blocks and compare the results with standard baffle blocks by using the Fluent program depending and the experimental results to achieve that. Values of the drag coefficient for different baffle blocks in this study were found in terms of the primary Froude numbers. Results indicated that values of the drag coefficient for the vertically cutted blocks were less than the horizontally cutted baffle blocks in the same flow conditions. Also, maximum values of applied pressures on the surface of the vertically cutted baffle blocks were less than on other models which makes them more better than others.

The modern idea of town planning is to plan it under the hierarchic design of service centers levels begin from neighborhood unit level to residential district. It’s done by using indicator numbers and areas, that the urban designer returned to them in the planning .this research aims to recognize the neighborhood units slandered by using the intelligent programs system to evaluated three plans of neighborhood unit designed by the researchers to make them in the right design .

The current research aimed to study the effect of fraud in the diesel fuel on environmental pollution, the study included two samples of diesel fuel., first sample is used currently in all diesel engines vehicles, and it produced in colander of oil of Baiji, the second sample is producer manually from mixing of the Lubricating oils and kerosene with ratio (1/40), were prepared and tested in research laboratories and quality control of the North Refineries Company /BAIJI by using standard engine (CFR). comparison between two models of fuel in terms of the properties of the mixing fuel and the properties of diesel fuel standard. The results proved that the process of mixing these , leading to the minimization of Cetane number and flash point. While the viscosity increase in mixing fuel, comparison with fuel producer in the refinery, and which identical to the minimum standard specifications of diesel fuel. The tests had been carried out using the engine of (TQ) four stroke type (TD115) with a single-cylinder and compression ratio (21:1) a complement to the hydraulic type Dynamo meter (TD115). Results proved that, by using manually mixed fuel the performance of the engine is decreased, and the break power is reduced to (6.49%) compared with (5.6%) for fuel produced in refinery at speed (2750 RP.M). also at the same speed the specific fuel consumption increase (5.6%) for the same compared . At the same speed the brake thermal efficiency and the volumetric efficiency are decreased by 5.7% and 3.12% respectively. While m the exhaust temperature are increased by 3.9% . The emissions also increase from the engine when using the fuel which produced from the mixing operation, were the increasing of (CO) and (HC) (9.5%) and (4.6%) respectively, from their values upon using the fuel which was produced in refinery.