Print ISSN: 1681-6900

Online ISSN: 2412-0758

Volume 31, Issue 1

Volume 31, Issue 1, January 2013, Page 1-196

Study of the Microstructure Semi Solid Al-Si-Mg Casting

Nawal Ezzat; Nada Taher Sultan

Engineering and Technology Journal, 2013, Volume 31, Issue 1, Pages 1-11

Semi-solid metal processing involves processing metallic alloys between the
solidity and the liquidity. The microstructure must be non-dendritic and consist of
spheroids of solid in a liquid matrix. In this work two potential routes are used:
First, The superheated Al-Si-Mg alloy was continuously cooled down to various
temperatures above its liquidity (620,630,640) o C . When the desired temperature of
the melt has been reached, then mechanical stirring with rotational speed of
(800)rpm for (30)sec. was started. The resultant slurry was bottom poured into a
stainless steel mold placed below the crucible. The solidified samples were reheated
to the semi-solid metal processing temperature, held there for (10) min, and rapidly
quenched in into water tank to retain the semi solid microstructures. In the second set
of experiments , the superheated melt was continuously cooled down to various
temperature in semi solid range (610,600,595,590,580)o C, then mechanically stirred
at rotating speed(800)rpm for (30)sec. the resultant slurry was bottom poured into a
stainless steel mold placed below the crucible. The metallic mold is then rapidly
quenched in water to room temperature. Metallographic examinations indicate that
the mixing method leads to highly globular semi-solid slurries of fine particle size.
The particle sizes of slurry quenched at various temperatures within the semi solid
metal range are much smaller when compared to the reheated structures. The particle
size gradually increases as the slurry temperature decrease.

Creep Behavior in Fiber-Reinforced Epoxy (DGEBA) Composites

Lubna Ghalib

Engineering and Technology Journal, 2013, Volume 31, Issue 1, Pages 12-25

The composite material was prepared by reinforcing the epoxy with E-glass fiber. The creep and flextural test were measured in this work for one and two layer of E-glass fiber with volume fraction rate of (10%, 20%, 30%, and 40%) in orientation of (0-90o) immersed in epoxy (DGEBA) resin with total thickness of 4mm. The tests were done at different temperature levels from (25 to 55)Co for creep test. The results had revaluated showing that the creeping properties of this composite materials will be improved with increasing the volume fraction layer of fiber at different temperature levels with constant stress. Creeping increases when the temperature increases and decreases with increasing of the number of layers and volume fraction of fiber. The creep constant increases with increasing the temperature up to 45Co then the creep constant down. The creeping energy of epoxy E-glass (epoxy composite) increases with increasing the volume fraction rate of E-glass fiber.

Enhanced GA for Mobile Robot Path Planning Based on Links among Distributed Nodes

Mohamed Jasim Mohamed; Mustaffa waad Abbas

Engineering and Technology Journal, 2013, Volume 31, Issue 1, Pages 26-41

In this paper, we propose an Enhanced Genetic Algorithm (EGA) to find the optimal path for a mobile robot. The workspace of the mobile robot is assumed to be of known environment with many static obstacles. The space of environment is divided into equally quarters by projection of a grid of specified distance on the environment space. Each quarter represents a node in the workspace. Moreover, each node has assigned by a unique number. So, all these nodes are distributed uniformly in the workspace. Each node may link to another node by straight line unless this line crosses one or more obstacles. New operator named Validation of Links operator introduces here to check all valid links between any two nodes. The GA operators adjusted and enhanced to suit the path planning problem and further more we develop new other operators to increase the efficiency of the algorithm. Simulation studies are carried out to verify and validate the effectiveness of the proposed algorithm.

Optimum Position of Shear Reinforcement of High-Strength Reinforced Concrete Beams

Omar Qarani Aziz; Sinan Abdulkhaleq Yaseen

Engineering and Technology Journal, 2013, Volume 31, Issue 1, Pages 42-52

This paper reports experimental data on the behavior and strength of high-strength concrete slender beams reinforced with vertical shear reinforcement. Tests were conducted on ten reinforced concrete beams with stirrups in different positions using high-strength concrete (compressive strength about 85.0 MPa). The beams measured 2000 mm long, 100 mm wide and 200 mm deep, and were tested under two point loads. The test variables were position and amount of web reinforcement; conventional steel bars were used as longitudinal reinforcement in this investigation. The test results indicated that beams with shear reinforcement (vfy = 1.65 to 4.24MPa) within the shear span (G1) and along the beam length (G2), were failed in flexure, while beams with shear reinforcement (vfy = 1.65 to 4.24MPa) between two point loads (G3) and the beam without shear reinforcement (G4) were failed in shear. The optimum position of stirrups is the shear span for high strength concrete beams and for different amounts

Investigation the Redistribution Stresses in Fibre Composite Materials Due to Break in Non-Uniform Fibre

Luay S. Al-Ansari; Ameen A. Nassar; Zainab M. Jassim

Engineering and Technology Journal, 2013, Volume 31, Issue 1, Pages 53-65

In this research, the effect of break in a composite material containing one fibre with non-uniform cross section area was investigated depending on Nearest Neighboring Load Theory. Using Shear Lag Theory, a new equation described the redistribution phenomena was derived starting from the Beyerlein and Landis s equation that deals with the redistribution phenomena in a uniform fiber composite material. A mathematical model described the redistribution stresses phenomena in normal stress due to break in non-uniform fiber of composite material was made. Also, the finite elements model was built using ANSYS 11.0 software.A set of numerical calculating was done in order to study the parameters (Width of the matrix and diameter of the fibre )affecting on the normal stress values and to verify the new equation. The comparison between the ANSYS results and new equation results was done and a good agreement was found.

Thermal Performance of Film Cooling for Two Staggered Rows of Circular Jet

Assim H. Yousif; Amer M. Al-Dabagh; Muwafag Sh. Alwan

Engineering and Technology Journal, 2013, Volume 31, Issue 1, Pages 66-80

The holes orientation and jet inclination angles are important parameters that control the development of the flow structures and the penetration and spreading of the jets. Experimental investigations that describe the film cooling performance for a two rows of staggered holes with opposite orientation angles are presented to determine the heat transfer coefficient and film effectiveness under different holes attitude. Experimentalin vestigations were done on a flat plate by using a single test transient IR thermograph technique. The attitude of the downstream row holes is fixed at inclination angle (θ=30°) and orientation angle of (Ɣ=0°), while the upstream row holes is fixed with opposite orientation angle (Ɣ=180°) and the inclination angles are changed three times as (θ=20°, 30°, and40°). Three different blowing ratios (BR) =0.5, 1.0, and 1.5 are used in experimental program at each case. Enhancements were observed, in which as theblowing ratio increased and the inclination angle of upstream row decreased, the film cooling effectiveness and heat transfer coefficient are increased.

Effect of Addition Carbon And Glass Fibers On Bond Strength of Steel Reinforcement and Normal Concrete

Rana Hashim Ghedan

Engineering and Technology Journal, 2013, Volume 31, Issue 1, Pages 81-97

The concept of composite materials using fibers as reinforcement is not new. The aim of composing materials is to improve some properties of the original materials. In civil engineering, fiber reinforced concrete was one of the topics of interest. Using fibrous concrete in reinforced concrete structures arises a question of how does it affect the bond strength between the concrete and reinforcing steel bars. Thus, the present experimental study are carried out to have a clear understanding of the bond strength between normal concrete with two selected types of fibers which were carbon and glass fiber and steel reinforcing bars. Forty five pullout cubic specimens of size 150mm were fabricated and tested to serve that purpose. They were divided into five groups to study the effect of some selected parameters such as, type of fiber (carbon and glass),reinforcing bar diameter(12mm,16mm and 20mm)and fiber to cement ratio(f/c) by weight(0.75% and 1% ). Also, three concrete cubes having the same size of the pullout specimens from each concrete mix were tested in compression to find their compressive strength. It was found that the addition of glass fiber with bar diameter=16mm has much effect in enhancing bond strength than that enhancement accrued by addition of carbon fiber, the bond strength increases by about 13.6 % and 4.5 % with the addition of 0.75% and 1% glass fiber. On the other hand, the bond strength increases as bar diameter decreases.The addition of the carbon or glass fibers increases the bond strength for specimens with smaller bar diameter and vice versa and the fiber(either glass or carbon) to cement ratio of 0.75% give higher bond strength than that of 1.0%.

Graphical and Energy Pattern Factor Methods for Determination of the Weibull Parameters for Ali Algharbie Station, South East of Iraq

Amani Ibraheem Al-Tmimi

Engineering and Technology Journal, 2013, Volume 31, Issue 1, Pages 98-106

The hourly mean wind speed data for Ali Algharbie station locations in south east of Iraq are collected and analyzed over a period of 1 year. The Data are fitted to the Weibull distribution function which is considered as the infrastructure to form a wind atlas for any country obtaining the Weibull distribution is necessary to determine the shape ( k) and scale( c) parameters. There are several methods that can be used to determine these parameters. This paper presents the comparison between two methods, Graphical method and the new method is called Energy Pattern Factor (EPF) method. It is found that the highest value of the shape ( k) and scale (c) in Jun. at the two methods and the lowest value in Oct. at the two methods and this corresponds with the highest (8.597m/s) and lowest (3.265m/s) value of hourly mean wind speed in these months. So the new method shows good agreement compared with the result of the Graphical method therefore, we recommend using this method to calculate the Weibull distribution parameters.

Mechanical Properties of Tempered Nanobainite Steel

Dhafir S. Al-Fattal; Najmuldeen Y. Mahmood

Engineering and Technology Journal, 2013, Volume 31, Issue 1, Pages 107-119

The mechanical properties of 62 SiMnCr 4 steel transformed isothermally at 280ºC for 5-hours were investigated. The hardness of nanobainite steel was equivalent to tempered martensite steel. The hardness decreases significantly at high tempering temperatures in excess of 500ºC. Yield strength of about 2GPa and ultimate tensile strength of 2.3GPa have been achieved for nanobainite steel. Furthermore, the high strength is frequently accompanied by relatively good percentage elongation of 8.25%. The strength decreases and the ductility increases with increasing tempering temperature. Nanobainite steel has a high charpy impact energy of 170 J which decreases linearly with increasing tempering temperature. Fatigue strength of nanobainite steel is higher than tempered martensite, its decreases with increasing tempering temperature.

Solutions for Water Hammer Phenomenon in the Low Lift Pump Station Located on Tigris River

Afreen emad

Engineering and Technology Journal, 2013, Volume 31, Issue 1, Pages 120-131

The goal of this research is to find the proper solutions of curing the water hammer which the suddenly shutdown of the electricity that supply the power to the pumps occurs it, where this case make the water return to the pumps with very high speed approach the pumping speed which make surge wave, usually the pumps and the pipes and valves would crushed according to this surge wave. When the studied hydraulic data was taken from the pump station located on Tigris river and also from the knowledge of the pumping capacity and the velocity of the pumps used in this station and input this data to (Bentley Software ) specialized in studying and locating the position of the water hammer support to locate the right place to put the surge tank which can absorbs the surge wave and finally to prevent the water from returning with very high speed to the pumps and to save the pumps, pipes and valves from crushing even when the electricity suddenly shutdown and depend on the standby generators to generate the electricity , the putting of surge tanks in the place of highest point of pressure make the pressure decreased from (22bar ) up to (7 bar ) approximately .

Bacterial Foraging Optimization Algorithm (BFOA) to Simulate Thermal Distribution in Yb:YAG Laser Thin Disk

Mohammed A.Minshed

Engineering and Technology Journal, 2013, Volume 31, Issue 1, Pages 132-155

There is a strong need for an optimized management of the thermal problem in Yb:YAG laser rod and for a powerful, fast, and accurate modeling tool capable of treating the heat source distribution very close to what it actually is. In this paper, a new optimization algorithm called Bacterial Foraging Optimization Algorithm (BFOA) is proposed for simulation of the radial heat distribution. A BFOA discloses a simulation method which delivers the exact temperature distribution in a circularly cylindrical structure with a circularly symmetrical, longitudinally, and transversally non-uniform heat source distribution and circularly symmetrical cooling means. its rod was end pumped with 940 nm and it has been tested with pump power ranging from 1Kw to 2Kw for radius pumping ratio of 1/2, 1/3, and 1/4, for both Top hat and Gaussian beam pumping . The output power is obtained and compared with previously published experimental measurements for different pump power and a good agreement has been found.

A Numerical and Experimental Study of Steam Condenser Working with Modified Rankine Cycle

Hisham Hassan Jasim

Engineering and Technology Journal, 2013, Volume 31, Issue 1, Pages 156-171

A Numerical and experimental study of thermal and heat transfer processes in a steam condenser operating in steam power plant with steam engine was developed to built analytical model using to predict thermal profile of condenser. Iterative technique between Engineering Equations Solver (EES) and Matlab programming was developed to find water properties .The exit water temperature, steam flow rate, geometric dimension (diameter and tube length) ,convection heat transfer coefficient of water and condenser efficiency were computed using the analytic model. Experimental results for a range of water flow rate (0.0153 to 0.0121 kg/s) with constant inlet water temperature of 25 were used to validate the analytical model. Compared with a validated model, the standard deviations of analytical model are less than 4%, and all errors fall into ±6%. Analytical model can be used to show the relation between thermal parameters.

Experimental Study of Heat Transfer Coefficients of Shell and Helically Coiled Tube Heat Exchangers

Sattar Jaber Habeeb Al-Jabair; Ammar.A.Hussain.A.AL-taee

Engineering and Technology Journal, 2013, Volume 31, Issue 1, Pages 172-196

This work presents an experimental study of the heat transfer coefficients of shell and helically coiled tube heat exchangers. Three heat exchangers with different coil pitches were tested for both parallel-flow and counter-flow arrangement. Water is used as working fluids in shell side and tube side. The study is conducted at the hot water mass flow rates ranging between (0.02 - 0.12) kg/s while cold water is kept constant at (0.055 kg/s). The range of inlet temperatures of cold and hot water are (19 - 28 °C), and (50 - 80 °C), respectively. All experiments were performed at the Dean Number for coiled side range of (3803 - 12117). The work is performed to evaluate the influence of the tube diameter, coil pitch, shell-side and tube-side mass flow rate, and inlet temperatures of tube-side over the axial temperature distribution of heat exchanger, effectiveness, modified effectiveness and heat transfer coefficient. The evaluating has been performed for the steady-state . The results indicate that the major effect on the axial temperature distribution of heat exchanger was the mass flow rate ratio (mr). Also the modified effectiveness decreased with increasing mass flow rate ratio. The main influence on the shell-side heat transfer coefficient was coil pitch. Develop an equation to correlate Nusselt Number as function of Reynolds Number, Prandtl Number, Dean Number and helical coil Number.

Building Program to Calculate the Statistical Information of the Concentrations of Metal Using GIS

Tariq Naji Otaiwi; Hameed Sarhan Ismael

Engineering and Technology Journal, 2013, Volume 31, Issue 1, Pages 1-13

This paper deals with building a program to deal with geographic information system files in the field of mineral concentrations of the materials. Where it is open shape file of all kinds and usage of the basic functions with the file such as exploring the file information (Spatial Data) , (Tabular Data) , (ZoomIn, ZoomOut) , (Identify) and (Pan) ... etc. The key Function of the program in addition to the above is to account the statistical information to the data that represent concentrations of mineral extracted for metals and materials of different concentrations of the land represented by the Shape file point and scales 1:25000, 1:100000 and 1:250000, the program has been built using the programming language Visual basic and program Mapobject.

A Comparison between Results of Compaction for Soil

Husam Hikmat Baqir

Engineering and Technology Journal, 2013, Volume 31, Issue 1, Pages 14-31

Compaction test is one of the important laboratory tests to determine the soil characteristic properties , as well as standard penetration test is the standard field test for identifying many properties of the soil of which are confined compressive strength and bearing capacity of the foundations .
In this study, a manufactured mechanical device is used to make a simplified simulation of a standard compaction Proctor test through a mechanism to facilitate an equivalent energy in a simpler way. A number of laboratory tests are implemented on different soils and a comparison between the results of examination of the new compaction device was made. The results of the standard compaction Proctor test and the results of the new apparatus are very encouraging.