Engineering and Technology Journal

Experimental investigation of film cooling from two staggered rows holes, backward and forward; of opposite injection angles has been done. The forward holes row was embedded in arc trench. The aim of using arc trench is to enhance the poor mechanical properties of that in rectangular trench. The results of film cooling performance are given here in a form of adiabatic cooling film effectiveness and heat transfer coefficients. In the tests test warm air is blown through tunnel, and cold air through the plenum chamber. When the warm air flowed through the test section it heated the model downstream. Infrared camera is used to measure the model surface temperatures. The comparison with the same holes arrangements and same holes and trench dimensions between existing rectangular trench results and present arc trenched showed that the film cooling thermal performance for both cases are approximately very close with slight differences, these differences are more or less according to the values of blowing ratios.

The present research deals with the study of the effect of Nickel Coating on the fatigue resistance of carburized and uncarburized AISI 301 stainless steel. Six groups of bending fatigue specimens were prepared for fatigue test.
Two groups of the carburized specimens were precoated with Nickel. The Nickel coated specimens were then case carburized at a temperature of (540°C) for 90 minute. The other Nickel coated specimens were then case carburized at a temperature of (950°C) for 120 minute.
Experimental results revealed an increase in fatigue resistance by (25%) for
Nickel coated specimens which are carburized at low temperature of (540°C) as
compared with the as received specimens.
The surface hardness was increased by 79.4% for those specimens that have been carburized at a temperature of (540°C), while the specimens that have been coated by Nickel then carburized at low temperature of (540°C) showed a 34.3% increase in surface hardness

This paper focuses on using Taguchi method to determine the optimum turning parameters such as spindle speed, depth of cut, and feed rate, denoted by factor symbols A, B, and C respectively. The effect of cutting parameters on tool wear is depended on the concept of removed weight from the tool metal during machining. The material that has been used as a workpiece is high carbon steel and carbide insert DNMG 443-15 as a cutting tool. Taguchi orthogonal array L9, quality characteristic "smaller is better", and ANOVA were used to achieve the goal of the research. The results obtained showed that spindle speed is the significant factor of the process followed by the feed rate in terms of their contribution in analysis. The optimum combination of parameters, which was found by applying Taguchi method, is that designated by A2B1C1.

Ultrasonic technology, as an innovative technology,was used for degradation of benzene in an aqueous solution under ultrasound frequency of 20 kHz at different temperatures with initial concentration of 100 and 200 mg/L. Kinetic and thermodynamic of benzene degradation in aqueous solution were investigated. While the mechanism of benzene sonolysis was discussed. The degradation rate of benzene increased with increasing electric power, sonication time and by decreasing liquid volume, temperature and initial concentration of benzene. The beneficial effect of which power electrical or ultrasound on removal rates is believed to be due to increased cavitational activity occurring at higher levels of power. As power increases, the number of collapsing (effective) cavities also increases, which is leading to enhanced degradation rates. Thermodynamic parameters indicated that benzene degradation was spontaneous and exothermic in nature. The obtained data was fitted through the pseudo-first order model

Forced convection heat transfer from arrays of microchannels was considered for fixed volume and fixed pressure drop constraints. Order of magnitude relationships were developed for the optimal dimension of a number of fundamental duct shapes including the parallel plate channel with rectangular, square, rhombus, isosceles right triangle, circular duct and elliptic duct. Using the exact analysis method to produce an approximate expression for the optimal duct shape was developed for all ducts considered. Where approximate analytical results show that the optimal shape is the parallel plate channel duct array but with addition a triangular or rectangular duct to the parallel plate, where the rectangular model give a percent of (52%) increasing in the heat dissipation higher than the circular at an aspect ratio about (b/a=0.4), while give a percent of increase about (87%) in the same aspect ratio compared with rhombus duct model in heat dissipation due to their ability to provide the most efficient arrays in a fixed volume. Comparison of the approximate results with exact results from the literature show excellent agreement for the optimal duct dimensions

Bluetooth is a novel radio indoor wireless technology supporting short range portable devices Ad hoc intercommunication. The evaluation of its performance has been receiving more attention lately. In this paper a Personal Area Network (PAN) was set up using few Bluetooth devices to assess Bluetooth's Asynchronous Connection Less (ACL) service of overlapped devices operate in close proximity. Ad hoc connections in Bluetooth network have been assessed based on experimental and simulation study in the presence of burst noise and traffics of concurrent transmissions on unlicensed spectrum 2.4 GHz. Measurements and simulation based results are presented to investigate the performance metrics; delivery probability, load and latency. It has been found that burst losses can trigger lengthy retransmission timeout

Water quality index is one of the most effective tools to communicate information on the quality of water to the concerned citizens and policy makers. In this study, an attempt has been made to assess the water quality of Tigris River within Baghdad using the overall Index of Pollution (OIP) for surface water and examine the applicability of OIP for Iraqi water bodies by comparison the results with previous scientific studies conducted for the same river. Twelve parameters were considered for estimation of OIP in Tigris River. It was found that mathematical equations given by OIP developers to estimate the index does not give a precise calculations, therefor, Microsoft excel (2010) for windows was used to extract value function curves for the individual parameter. According to OIP, the river water is heavily polluted at Al-Doura WTP and Al-Rasheed WTP and the total coliform bacteria (TC) was the major factor that affects the quality of the river. Based on previous scientific studies, it was noticed that the OIP is not quite applicable in assessment of Tigris river quality and even the previous studies that were conducted for the same river and used different water quality indices, it was found that some contrarieties and variations in the results of these studies when compared between each other. Therefore, develop a unique water quality index applicable to Iraqi water bodies is of a prime importance.

The purpose of this paper is to design a model predictive controller (MPC) to improve the performance of electric furnace system to the desired requirements. The presence of delay in the system especially, the long delays makes analysis and control design much more complex. Unlike time delay compensation methods, the predictions are made for more than one time delay ahead in the MPC since the Future values of output variables are predicted using a dynamic model of the system and current measurements. From the analyzed and compared results it is noticed that the system response with MPC shows high tracking performance in transient and steady state

Biped robot has become more general purpose in our live as general behavioral patterns. It can walk very similar to human walking pattern. Therefore, many robots have been researched and developed in recent years. Through this paper a planner biped robot is modeled for specific task. This paper tries to explore the potential of using Simulated Annealing (SA) methodologies in the Inverse Kinematic Problem (IKP),utility and effectiveness of this method for the solve IKP of biped robot is presented. It presents a new objective function to find the optimal posture of biped robot by employing some constrain in the objective function to meet best posture. A comparison between the proposed method and the classical method using Genetic Algorithm (GA) are made through the Matlab 2009a software to show the efficiency of the new method. Experimental results demonstrate that better performance can be achieved with this method

In the present study mathematical representation was used to predict the reaction kinetics of the n-octane aromatization which tested with three types of catalysts by adding (Ge, Cs, and Re ) in order to improves the catalytic properties (enhanced the activity) of Pt/Al2O3 catalyst for n-octane aromatization. The aromatization process carried out in the range of reaction temperature varying from (425 to 500 °C) and weight hour space velocity varied from (0.6 to 1.2 hr-1) with hydrogen as the carrier gas at atmospheric pressure.
The results showed that the higher conversion of n-octane aromatization increased with temperature increasing but at temperature higher than (500 °C) hydrocracking reaction is promoted. Whereas the effect of weight hourly space velocity has shown inverse impact on conversion. On the other hand the yield of aromatic increase especially benzene and toluene which produce as secondary products from the hydrogenolysis of A8 for three types of catalysts using in the process under the same operating condition. The simulation results of the model based on proposed kinetic model was compared with the experimental results. The comparison between the predicted and commercially results shows a good agreement with error% between (6.91 – 17.87).

Dynamic effects of the machines play a major role in sizing of the foundation where conditions, like resonance is avoided by varying the stiffness and the mass of the structure which leads to modifications in foundation sizes. In this paper, a piled machine foundation in sandy soil is analyzed. A detailed 3D finite element analysis approach is considered using finite element software (ANSYS v.11). Machine foundations resting on end bearing piles are modeled. Harmonic dynamic load is chosen. A parametric study is carried out to investigate the effect of several parameters including: geometry of the piled machine foundation, the amplitude of the dynamic load, and frequency of the dynamic load.
It is concluded that as the pile cap thickness increases, the oscillation of displacement decreases due to geometrical damping of the pile cap. There is a limit of pile cap size at which its stiffness governs its dynamic response, above this size, the weight of the cap overrides its stiffness effect, and the additional weight by cap leads to increase the foundation displacement. On the other hand, when the pile diameter of the group increases, the frequency, at which the maximum displacement occurs increases hence the system becomes more stable against resonance condition

The present work involves using Impressed Current Cathodic Protection Technique (ICCPT), to prevent corrosion of buried underground steel pipelines. Polarization method using galvanokinetic technique was used to study the behavior of steel pipelines in Iraqi soil. The soil resistivity in this work is equivalent to NaCl solution (5, 10, 15, 20 and 25) NaCl concentrations. The resistivities play a strong role in corrosion rates, where corrosion rate increases with decreasing environment resistivity and increases with increasing the concentrations of NaCl for constant surface area. The object of this study is using a cathodic protection system by impressed current supplied with solar energy panels applied to steel pipelines. The efficiency of cathodic protection depending on the soil resistivity in the present work with different electric source and solar energy source are reached to the (92.3-94.5).

ABSTRACT
In this paper, a suitable design of a dc controller is proposed and implemented, as a prototype and for a software simulation, so that is capable to overcome different hazards in operation. Different techniques were selected to reach the efficient operation speed control unit. A simple and efficient firing unit is built, especially for this controller which can be implemented and repaired. The armature model has been built up and it is used in the simulation design in order to represents the armature rotation and operation study possible under different conditions. From the OrCAD Pspice 16.9 Simulator ,some transient and steady state results were taken like (voltage, current, torque, speed),at load and no load conditions. An open loop prototype drive were implemented and operated, so that deferent results were taken, this results comparing with a theory refers to good agreement

This paper presents an artificial neural network based control scheme for studying the control of continuous stirred tank reactor, distillation column and neutralization process and this method is compared with conventional proportional-/integral-derivative controller. A multi-layer back-propagation neural network is employed to model the nonlinear relationships between the inputs variables and controlled variables of processes in order to regulate the manipulating variables to a variety of operating conditions and acquire a more flexible learning ability. The robustness of this control structure is studied in the case of setpoint changes and load disturbances. The experimental results suggest that such neural controllers can provide excellent setpoint-tracking and disturbance rejection. The neural network based control has higher speed of response and the offset has a smaller average value than that of the conventional controller. The control action based on the neural network controller shows less oscillation and an improvement in the controlled variables stabilization time with respect to the conventional controller and gives a better control performance

This paper presents a nonlinear PID neural controller for the 2-DOF vehicle model in order to improve stability and performances of vehicle lateral dynamics by achieving required yaw rate and reducing lateral velocity in a short period of time to prevent vehicle from sliding out the curvature. The scheme of the discrete-time PID control structure is based on neural network and tuned the parameters of the nonlinear PID neural controller by using a particle swarm optimization PSO technique as a simple and fast training algorithm. The differential braking system and front wheel steering angle are the outputs of the nonlinear PID neural controller that has automatically controlled the vehicle lateral motion when the vehicle rotates the curvatures. Simulation results show the effectiveness of the proposed control algorithm in terms of the best transient state outputs of the system and minimum tracking errors as well as smoothness control signals obtained with bounded external disturbances.

A quasi-steady finite-volume model was developed for modeling a plain-fin-round-tube heat exchanger under frosted conditions. In this study, the heat and mass transfer characteristics of heat exchangers during frost formation process are analyzed numerically. Unsteady heat and mass transfer coefficients of the air side, heat transfer coefficient of the refrigerant side, frost layer thickness, the surface efficiency of the heat exchanger and the mass flow rate of the frost accumulated on the heat exchanger surface are calculated. The total conductivity (UA) and pressure drop of the heat exchanger are reported for different air inlet and refrigerant temperature. Results have shown that frost layer growth is faster with lower inlet air temperature. Using the developed mathematical model, the algorithm and the computer code, which have been experimentally validated, it is possible to predict a decrease of exchanged heat flux in the heat exchanger under frost growth conditions. The model could be further extended to simulate direct expansion evaporators with varying operating conditions and variable heat exchanger geometry.

In this research, a study has been made on the effect of high fractional volume of replacement Metakaolin that results from grinding and burning the local kaolin from (Doeakhla zone / west of Baghdad / Iraq) with fineness of 18000 cm2/gm., and with temperature 700°C for one hour, on some properties of concrete (compressive strength, splitting tensile strength, flexural strength, modulus of elasticity, density, absorption and drying shrinkage). Also, non-destructive tests have been made (Schmidt rebound hummer and Ultrasonic pulse velocity). In this study, ten concrete mixes have been used in two Groups to get a compressive strength 40 N/mm2 at 28 days. In Group A, the percentage replace of Metakaolin have been changed from (0-70) % by weight of cement with percent increment equal to 10% for each mix, and change the maximum size of aggregates to determine the effect of changing the surface area of aggregate as variable on the properties of concrete-containing Metakaolin, The tests for all mixes were made at ages ranged from 1 day to 90 days after mixing and replacement a dosage of superplasticizer by water content of the mix to make a constant workability with slump 50±5mm. The aim of this research is to find a type of concrete that can be used in dams as one of the types of mass concrete, concluded from this research that replacing 70% Metakaolin instead of cement mixing the compressive strength aged 90 days less than the 63%, splitting strength at 28 days less than 27%, flexural strength at 28 days less than about 27%, the modulus of elasticity at 28 days less than 54%, density of less than about 8% at 28 days, the absorption rate increases about 27% and drying shrinkage 1.65 * 10-4 at 60 days when compared all these tests with the reference concrete

Electrical Resistivity Imaging (ERI) method is one of the most promising techniques which is well suited to applications in the fields of geohydrology, environmental science and engineering. The present work is aimed to show the efficiency of 2D Electrical Resistivity Imaging (ERI) and Induced Polarization (IP) in probing the subsurface soil for site investigation and differentiating the clayey soil layers as it is a common practice to measure the IP sounding along with resistivity for correct interpretation of field data. The study has demonstrated the practical application of 2D ERI and IP tomography along 7 lines using Wenner- Schlumberger array. The data analysis comprises of 2D inversions using the RES2DINV software, thus 2D electrical resistivity and IP imaging sections have been obtained. The depth of investigation was 4 m, and resistivity values range from <1 to 292 ohm.m. Two electrical layers were recognized: the upper layer with high resistivity (7-71 ohm.m) represents the loamy soil extends to a depth around 1.3 m; and the second layer with low resistivity (<1-9 ohm.m) represents the clayey layer. Some anomalous low and high electric zones are appeared reflecting the inhomogeneity in deposits. The IP values are ranging from -2 to 15 mV/V showing good confirmation with resistivity data, where high chargeability are associated with low resistivity. The study reveals that combining IP with resistivity surveys is recommended since IP is, sometimes, very effective in relieving ambiguity in interpretation

Interleavers are essential system components for interleave division multiple access (IDMA). In this paper, two-stage interleavers are proposed based on two optimization criteria combines minimum spreading distance with regular permutation and randomization properties to have almost the same advantages of the random distribution, and yet guaranties an enlarged minimum spread distance. Simulation results show sufficiently good performance with much less resource consumption compared to multiple random interleavers. The proposed method may also find other application areas such as multi-dimensional concatenated codes. In addition, an efficient and simple procedure is proposed to generate orthogonal interleavers by using the well-known Walsh-Hadamard transform

This paper deals with estimating parameters and reliability function for the
general linear failure rate distribution, which is an important probability
distribution for studying the time to failure for machines and equipment. The
parameters of location ( ), and scale parameter ( ), were estimated, while the
shape parameter ( ) considered known. Three statistical methods are used for
estimation which include maximum likelihood method, least square method, and
proposed method including finding a mixed distribution, from using maximum
likelihood and lest square estimator with proportion ( ), (1− ). The comparison
between estimators has been done through simulation procedure using different
sample size like ( = 15, 30, 50, 75, 100), and each experiment is replicated
( = 1000). The comparison done using the statistical measure mean square error
(MSE), all results of comparison were represented in Tables