University of Thi-Qar Journal for Engineering Sciences

Vehicles that use highway facilities have increased rapidly last decades mainly due to increasing of population and also due to industrials development for vehicles. In Iraq, it has been noticed that the car ownership has been increased since the year of 2003. This paper uses real data taken from the Central Statistical Organization of Iraq (CSO) to focus on car ownership in Iraq as a whole as well as focusing on each province separately. The finding of this paper highlighted the ongoing traffic problems due to sharp increase in the number of vehicles and the unusual traffic growth rate. The expected number of vehicles during the next 10 years is estimated and expected to increase from 4.5 million on 2013 to be as minimum as 11 million private cars. This will create a new challenge for Iraq roads infrastructure which must be enhanced significantly so as to cover such increase in traffic. The results suggest that the average car ownership per 1000 people is increased from 58 to 124 from 2003 to 2013. The average car ownership per households has also increased from 0.39 to 0.83 vehicles per households. Significant differences in car ownership rates are found among Kurdistan, middle and south regions in Iraq. The annual traffic growth rate during the last 10 years of 11.5% is found which is much higher than the population growth rate of 3.14%.

Spherical storage tanks are widely used in Iraq for store hazardous liquid petroleum gas LPG which, thus it must be adequately designed for seismic actions. This paper present static and time history analysis of LPG tanks in Iraq using UBC97 code. The time history analysis accomplished by using three artificial earthquakes generated using SIMQKE_GR program in additional to El Centro earthquake records scaled according to PGA. The investigations were performed on the tank in Maysan province which was selected to be representative the other tanks in Iraq due to recently seismic activity in Maysan. The study comprised finite element modeling using STAAD Pro program for the estimation of the dynamic and static responses of the tank structure. The study is performed for both conditions of empty tank and at operating with 100% fill of LPG. The description of the properties and allowable stresses LPG tank used in Iraq is presented. Its concluded that time history analysis govern the tank behavior. The dynamic magnification factor of 1.4 for displacements and stresses was obtained which reflect the importance of dynamic analysis. The stresses of columns and sphere are within allowable limits except at sphere/column connection which slightly exceed the allowable limit, while the stresses in diagonal bracings are exceed the yielding limit thus double angle section is inadequate

The main function of the vehicle suspension system is to provide comfort for passengers, road handling and vehicle stability. This paper proposes the application of PID controller (proportional, integral and derivative controller) for active suspension system of a half automobile model using MATLAB / SIMULINK. Time domain simulations are carried out to test the performance of the suspension system under different types of road profiles which are the primary inputs of the system. In this paper, three types of road profile inputs (bump, sine wave, random wave) are introduced to excite the suspension system. According to these road profile inputs, the performance response of passive and active suspension systems is simulated. Simulation results show that there is a significant improvement in the performance of the active system over the passive one.

This paper deals with design and simulation of Proportional plus Derivative (PD) controller for two links robotic arm. The PD controller was used to compute the required joint’s torque for tracking the desired trajectory. The Particle Swarm Optimization (PSO) algorithm has been used in order to tune the gains of the proportional and derivative parts of PD controller. Simulation results show an efficient and robust behavior of the proposed controller. Two cases of simulation tests were carried out. The first was tracking a sine wave trajectory while the second was tracking the same trajectory with the presence of disturbance torque on the dynamic model of the robotic arm. The simulation results were compared with the presence of disturbance torque on the dynamic model of the robotic arm. The simulation results were compared with the results obtained by other researchers, for similar robotic arm properties and same trajectory. The proposed controller offers a simple method for trajectory tracking problem with a satisfactory efficiency. A Mean Square Error (MSE) criterion was used to study the efficiency of the proposed controller in tracking the desired trajectory.

The amount of drag produced significantly depends on shape of the airfoil. These implementation concerns the lift and drag analysis of three different profiles of airfoils, which are symmetrical aerofoil (NACA 0015, NACA0012) and cambered aerofoil (NACA 4415) have different volume. NACA0015 is provided with perforated tube fixed at 75% from the leading edge for suction. Electrical control system used to control the suction operation the three different types of objected has been tested at a sub-sonic wind tunnel and experimental data has been obtained at different Reynolds’s number and angle of attack. The three airfoils (symmetrical NACA 0015, NACA0012 and cambered with NACA 4415) tested at (00, 50, 100, 150 and 180) angles of attack. All the three objects tested at Re (1.72, 2.9,4, 5.2 and 6.3 x105). The cambered airfoil has been given least drag among than all the airfoils. The drag force of all test model are decreased when the value of Reynolds number are increased and NACA 4415 exhibit less drag and high lift in comparison with other models that used in this study. Suction technique is more active at lower values of Re –number.

A series of siloxine centered side chain liquid crystal polymers have been arranged with asystematic variation in spacer length. All the polymer shown a nematic phase, for which the nematic-isotropic transition temperature increased as the spacer length bigger. The mesogenic group has syano head groups (C N) to which positive dielectric anisotropic ( ) is accredited to bind the mesgneic group with the backbone we have used elastic spascer of (CH3) which changes from )2) to (6) units. The nematic cells that have been arranged have planer reorientation to notice the changes inside electro-optic cell Frederick's transition manner. It found that with increasing spacer length (n) of polymer the threshold voltage is let down. It been also institute that there is a reverse relationship between temperature and response times this scholarship also deals with the effect of elastic spacer on response times and it has been learned the response times of the polymer with short spacers are longer than response times of the polymers with long spacers, in addition the response times of the three polymers are in reorientation the spacer length lastly we have been found that there the increase in applied voltages lead to the lessening in turn on times (TON)with the turn off times (TOFF).The difference of the threshold voltage ascends from changes to the intrinsic curvature elasticity rather than to the differences in the orientation demand

Many researchers adopted the quasi static roll over testing in the calculation of a prototype prosthetic feet roll over shape. In this work, the prototype of a new carbon fiber prosthetic foot was tested for roll over characteristic. An inverted pendulum like apparatus has been built to achieve the required test, and the prosthesis roll over shape calculated. Roll over characteristics were estimated as: effective radius of curvature about 202mm, center of curvature of 26.55mm, and the forward travel against shank angle was plotted.

Effect of insertion combined screw and twisted tapes in a heated tube fitted with converge-diverge conical turbulators on Nusselt number, friction factor and overall performance factor has been experimentally investigated. The air is the working fluid for Reynolds number variety of 15000-65000. The conical nozzles used as turbulators are located inside the heated tube with the combined twisted and screw tapes. The considered compound case is compared with the single twisted and screw tape. The twisted tape is used for three various twist ratios (Y/W=3.0,5.0,and 7.0), while the screw tape for one screw ratio equal to 3.0 . It is discovered that the combined tapes with conical turbulators enhance considerably the heat transfer over that of the conical turbulators alone by about 47.7% and 43.18%,and 39.7% for twist ratio of 3.0,5.0 and 7.0 respectively. The optimal thermal performance is pointed for screw and twist ratio equal to 3.0

The objective of this work is to study the dynamic behavior of FG pipe conveying fluid lying on the visco-elastic foundation using differential quadrature method. The material properties change constantly across the pipes thickness and depend on power law distribution. The vibration equations for FG pipe are obtained by using Hamilton's principle based on the Euler- Bernoulli model with (Clamped-Free) boundary conditions. An efficient numerical method by differential quadrature (GDQ) is developed to find the natural frequencies and stability for FG pipe. The effects gradient index and foundation parameters in fluid conveying FG pipes with certain flow velocity on frequencies are investigated. The present method of solution is accurately checked by comparing their results for fluid conveying pipe with the available results in the literature. From the comparison, a reasonable agreement was found. An increase in the gradient index results in an increase in the critical velocities for FG pipe.

Parametric optimization of the transformation process is a task of improving multiple objectives. In general, no single set of input parameters can provide the best hardness of the metal and the best finish of the surface at the same time. While when using the genetic algorithm proved that it is possible to obtain more than one goal of the function at the same time. In the current research the use of Multi-objective particle swarm optimization (MOPSO) to determine the best hardness of the metal and less roughness of the surface operator at the same time. A mathematical model was also developed to predict the hardness of the metal and surface roughness using Taguchi technology depending on the input variables (cutting speed, cutting depth and feeding rate). Experiments were conducted on a CNC machine in turning carbon steel AISI 1025 using carbide cutting tool. It was found that the most influential factor on the surface roughness is the feeding rate, while the most important effect on the hardness is the cutting speed.

In this paper, two types of stresses acting on the single rotor blade of low pressure steam turbine for Nasiriya power plant were studied. The first type of stresses was the stresses due to pressure force on the single rotor blade, while the second type of stresses are the centrifugal stresses. The stresses due the pressure force were studied in this paper at three loads (70, 140, 210 MW), while the pressures acting on the first rotor blade of steam turbine were 512, 3311.7, 6496.8 Pa respectively . In addition , the blade was fixed at the root and free at the end, while the rotational speed of blade was 341 rad/sec was applied as rotational load. The results showed that the rotational load has the greatest effect on the blade. Also the stresses due to rotational load are higher than stresses due to steam pressure at the three loads.