Print ISSN: 1681-6900

Online ISSN: 2412-0758

Volume 26, Issue 3

Volume 26, Issue 3, March 2008, Page 62-392


Effect of Shot Peening on Fatigue Strength of Welded Joints For Low Carbon Steel

Engineering and Technology Journal, 2008, Volume 26, Issue 3, Pages 95-103

The aim of this work is to study the effect of the time of shot peening with
steel balls of 1.25 mm in diameter on fatigue strength of butt joints for low carbon
steel (1020 AISI) welded by metal arc welding shielded with CO2 gas
(MIG/MAG). All fatigue tests were of the rotary bending type at mean stress of
zero for welded unpeened samples and shot peened samples at various times.
It was found that all the shot peen times of (10,20,30) minutes have improved
the fatigue strength and the best strength has been achieved at the time 20 minutes
because of the high compressive stresses induced by the shot peen process and in
addition to the denteritic microstructure in the weld zone for unpeened samples .

Friction and Wear of Aluminum-Silicon Alloys

Engineering and Technology Journal, 2008, Volume 26, Issue 3, Pages 104-114

The effect of iron and lead that added to Al-13%Si alloy on the phases, friction
and wear characteristics were studied. All friction and wear test specimens were dry
slided on the carbon steel disc at a wide range of different bearing pressures (3.74-
187.3 Nm-2 x 103). XRD patterns analysis showed that there are three phases presented
in the matrix of Al-13%Si alloy after iron and lead addition. These phases are eutectic,
lead and Fe2Si2Al9. While two phases were presented in the matrix of Al-13%Si alloy
which are eutectic and primary silicon. The results also showed that coefficient of
friction and wear rate were increased with iron and lead addition in a magnitude
dependent on the bearing pressure. Furthermore, wear mechanisms were dependent on
the alloy phases, hardness and bearing pressure.

Study on Some Electrical Properties of Coumarin In (Ethanol – Water) Mixtures with Three Weight Percentage at Five Temperatures

Engineering and Technology Journal, 2008, Volume 26, Issue 3, Pages 115-130

This research involves the study on some electrical properties such as dielectric
constant (D), molar conductivity (Λ) and the calculation of molar polarization (P)
and ion- pair formation constant (KA) in three (Ethanol – Water) mixtures
containing (50, 70, 90%) of ethanol at five different temperatures in the range
(293.15 – 313.15)K.

Cathodic Protection of Steel Reinforcement in Concrete

Engineering and Technology Journal, 2008, Volume 26, Issue 3, Pages 131-142

The present research has be investigated the relation between the induced
level of polarization and the area of the embedded steel, area of the anode, the
concrete resistance and the level of applied external voltage. During exposure
period, the specimens were polarized using three different levels of external
voltages (750, 1000, 1500) mV. Various electrochemical and electrical
measurements were made, these include half cell potential, degree of polarization,
flowing current and the actually applied voltage as compared with the external one.
The results indicate differential moisture content in each specimen has
produced different potentials along the steel bars. Greater polarization has always
been associated with the submerged portion of the specimen where the concrete
resistance is at its minimum. whereas the degree of polarization is directly
proportional to the level of external voltage. The results also illustrate that, for a
given level of externally applied voltage, the degree of polarization is dependent on
the area of protected steel and the area of the anode. Thus the polarization increases with the decrease in the protected steel area and the increase of the area
of the anode.

Application Studies for Reducing the Harmful Vibrations on Blades of High and Low Pressure Stages of Steam Turbines

Safaa H. Abdulrahman; Adnan D. Mohammed; Mohammed A. S. Salih

Engineering and Technology Journal, 2008, Volume 26, Issue 3, Pages 278-290

In this work the dynamic behavior of blade disc - turbo rotor - bearing system is
investigated analystically using the transfer matrix method, also the analysis
applies the finite element method ( Ansys Package ) choosing the brick type
element, for comparison of the results. The major aim of this paper are to study the
effects of varying the temperature, fluid flow impact on the blades surface; losing a
faction of the blade mass to have imbalama in system; blade root flexibility and
centrifugal force along the blade length; gyroscopic moments, damping and
stiffness values of bearings on the dynamic behavior of the blade disc – Turbo
rotor – Bearing system.

Preparation Activated Carbon of From Iraqi Reed

Najat J. Saleh; Mohammed I. Ismaeel; Raheek. I. Ibrahim; Mummtaz A. Zablouk; Ali amer

Engineering and Technology Journal, 2008, Volume 26, Issue 3, Pages 291-304

In this work activated carbon (AC) was successfully prepared from local
raw material namely Iraqi Reed .This source is cheap and available and in this
work AC is prepared from it for the first time. A chemical method using zinc
chloride was used in the activation process. The proper carbonization temperature
was found to be 450 oC and the time required for carbonization was one hour. The
adsorption capacity for acetone of the prepared AC was measured and found to be
15.6%. Some important properties were also studied such as: apparent density
(0.451 g/cm3), ash content (9.4%), moisture content (4.8%). The x- ray
diffraction also showed that AC exhibited a poorly crystalline structure, with a
little amount of silica and graphite.
Decolorization capacity (DC %) of AC on: (a) Caramel dye solution (b) Potassium
permanganate solution, were studied. The effect of quantity Of AC and contact
time was investigated using UV- spectrophotometer. It was found that
decolorization capacity DC% of KMnO4 solution (93%) and it was better adsorbed
within one hour, while DC% of caramel dye solution was (87%) and it was a better
adsorbent for the color within two hours. It is concluded that AC prepared in this
work has a good specification compared with standard sample thus it is suitable for
industrial uses.

Robust-Load Frequency Controller Design For Iraqi National Super Grid System

Rashid H. Al-Rubayi; Lokman H. Hassan Al-Sharafany

Engineering and Technology Journal, 2008, Volume 26, Issue 3, Pages 305-325

This work is intended to design a new robust load-frequency controller for
Iraqi National Super Grid System with uncertain parameters. Riccati equation
approach to the stabilization of uncertain system is proposed. Robust controller that
ensures stability of the closed-loop system for all admissible structured uncertainties
is designed. ‘Matching conditions’ and Lyapunov stability theory are used to
implement a robust stabilizing controller. Participation factor is used to address the
interaction between the state variables and the modes in the power system. This
property is used to choose weighting matrix of the state variables (Q). A linear, time,
invariant mathematical model is derived for Iraqi National Super Grid System
consisting of six generating stations with various types of turbines. The proposed
approach is applied to this system and simulation program is built to evaluate its
effectiveness.

Prediction of Surface Roughness in End-Milling with Multiple Regression Model

Saad Kareem Shather; Abbas Fadhel Ibrheem

Engineering and Technology Journal, 2008, Volume 26, Issue 3, Pages 326-337

In this Paper, we propose statistical package for social sciences (SPSS), to predict
surface roughness. Two independent data sets were obtained on the basis of
measurement: training data set and testing data set. Spindle speed, feed rate, and
depth of cut are used as independent input variables (parameters) while surface
roughness as dependent output variable. The multiple regression model by using
(SPSS) could predict the surface roughness (Ra) with average percentage deviation
of 7.8%, or 92.2%, accuracy from training data, and from testing data set that was
not included in the multiple regression analysis with average percentage deviation
of 11.95%, or accuracy of 88%, for 4-Flute end mill.

Evaluating the Hydraulic Performance of Al Msharah River

Mahmoud S. Al Khafaji

Engineering and Technology Journal, 2008, Volume 26, Issue 3, Pages 338-350

Al Msharah River is one of the main controlled feeders of Al
Huwayza Marsh in addition to its importance in irrigation of the
nearby agricultural areas. A study for evaluating the hydraulic
performance of this river has been carried out to develop the ability of
the river to accommodate the increase of the required discharge for
feeding the marsh and agricultural projects. Achieving this objective
require carrying out field hydrological measurements, stage and
discharge, at a number of stations distributed along the river for period
of six months. A steady one dimensional hydraulic model has been
prepared to simulate the flow in this river using the HEC-RAS
software (Version 3.1.3). The calibration and verification processes of
the model have been carried out by making use of the field
measurements. The maximum allowable discharge of this river for the
present conditions has been found and the failure, flood, locations
have been specified along the river. The required cross sections to
develop the capacity of the river have been found considering the
marsh and agricultural requirements.

A Natural Language Steganography Technique for Text Hiding Using LSB's

Hana; a M. Salman

Engineering and Technology Journal, 2008, Volume 26, Issue 3, Pages 351-364

Steganography is the art of hiding, and transmitting information using
apparently innocent carrier without expose any suspicion. This paper present a
natural language steganography technique, which is different from all the natural
language steganography technique, that uses structure of the sentence constituents
in natural language text in order to insert a secret hidden information, or all others
techniques, which hide information by modifying the appearance of text elements,
such as lines, words, or characters. The proposal technique use the secret hidden
text information to generated the stego-cover carrier text by using algorithms
depend on natural language processing, particularly text generation field. A survey
for natural language terminology, techniques, and tools for text processing, a
natural language steganography technique and its difficulties to implement
methods like LSB's is presented. The results shows that, the proposal technique is,
a successful one in implementing methods like, LSB's for natural language bit
steganography .

Performance Enhancement of GSM Cellular Phone Network using Dynamic 365 Frequency Hopping

Hosham Salim; Hussein Bli

Engineering and Technology Journal, 2008, Volume 26, Issue 3, Pages 365-375

A fundamental problem in current cellular system is how to increase spectral efficiency of cellular system and
handle blocking in the call between the subscribers. The present research offers solution to the above problem.
In this work software simulator that can be used in the environment of cellular system is designed and
implemented. This designed system shows how to increase spectral efficiency and enhancement blocking
probability in cellular system by using Dynamic Frequency Hopping techniques. In this paper received power(Pr)
threshold is proposed as one method of Dynamic Frequency Hopping technique. In each frame, received power is
measured on the six used frequencies and the current hopping pattern is changed if the measured received power
does not achieve the required threshold on at least one of them. The results indicate increasing the spectral
efficiency by using Dynamic Frequency Hopping technique, the result of spectral efficiency versus traffic load
with Dynamic Frequency Hopping is equal to (6.5 b/s/Hz), compared with Frequency Hopping (5.2 b/s/Hz) and
GSM (3.5 b/s/Hz). This leads to an improvement in performance of system and reduce the interference allowing
the users to achieve higher data rate.

Treatment of Expansive Clayey Soil with Crushed Limeston

Al-Hayalee; Mohammed Thafer; Al-Khashab; Mohammad Natheer

Engineering and Technology Journal, 2008, Volume 26, Issue 3, Pages 376-386

This paper aims at the improvement of expansive clays, by the addition of crushed limestone, obtained from
the waste of masonry factories situated in the polluted industrial area, to the east side of Mosul city. This
abandoned waste material creates serious environmental problems in the areas surrounding these factories
requiring an urgent solution to dispose of the huge quantities heaped in there.
Different percentages of the crushed limestone by weight (passing sieve No.40) were added namely (2, 4, 6,
8, and 10%) to the clay obtained from "Al-Wahda district in Mosul" to reduce its expansiveness and
improve its characteristics for many earth work construction. The test results showed pronounced reduction
in the plasticity of the clay and significant decrease in the swelling properties, in the range of more than
three and half times that of untreated one. These results represent very important factor for road
embankment constructions.

Mixed Alkali Effect on Viscosity of Sodium Potassium Borate Glasses

Saad B. H. Farid

Engineering and Technology Journal, 2008, Volume 26, Issue 3, Pages 387-392

The effect of the alkali oxide content on viscosity has been studied
for sodium-potassium borate glasses. The deviation of viscosity values from
additivity has been modeled to investigate the effect of partial substitution
of one alkali oxide for another. Published data on isokom temperatures and
activation energies for sodium-potassium borate glass compositions has
been utilized along with L2-regression optimization technique for analysis.
It is found that both linear and nonlinear relations determine the
viscosity coefficients associated with chemical components of the glasses
under study. This model allows the calculation of viscosity for a given
temperature and accordingly, the fusion temperature of these glasses.
Furthermore, the established model relations show first and second order
mixed alkali effect on viscosity.