Print ISSN: 1681-6900

Online ISSN: 2412-0758

Issue 6,

Issue 6


A Numerical And Experimental Study of Louvered Fin Heat Exchanger Performance

Jalal M. Jalil; Aamer Al. Dabagh; Assel Kh. Shyaa

Engineering and Technology Journal, 2010, Volume 28, Issue 6, Pages 1038-1049

The louvered fin heat exchanger is a very widely used method to increase the
compact heat transfer coefficient on the air-side of condensers by adding fins and
initiating new boundary layer growth and increasing surface area. The governing
equations of such application are the Navier Steckes equation and energy equation. A
two-dimensional, turbulent, compressible flow is simulated and solved. The solution
gives the distributions of velocity and temperature (which is represented by Nusselt
number). Laminar and turbulent flow were studied experimentally and only turbulent
flow was studied theoretically, for a range of ReLp 230 to 8100 with constant inlet
temperature of 21C˚with two angles of louver fin 27˚ and 35 ˚. The ideal geometry for
heat transfer performance was determined to be dependent on Reynolds number. At
lower Reynolds number the optimal geometry was found to be θ = 27º and at high
Reynolds number the ideal geometry was determined to beθ = 35º, Fp/Lp = 0.587

Optical and Optoelectric Properties in PbCdS Ternary Thin Films Deposited by CBD

J. P. Ponpon; Ali M. Musa; Modaffer A. Mohammed

Engineering and Technology Journal, 2010, Volume 28, Issue 6, Pages 1050-1060

PbxCd1-xS films have been prepared in the composition range of 0.05£ x£0.25
by using a chemical bath deposition growth technique under optimum conditions
to deposit good photo response. X-ray diffraction study results show that the films
are of PbS-CdS composite with individual CdS and PbS planes. The films
exhibited two direct band gaps, 2.4 eV belongs to CdS, and the second varies
continuously from 2.4eV to 1.3eV. The surface morphology of the films is smooth
with crystallite of increasing grain size with increasing the mole fraction (x). The
decrease in the band gap with increase in lead concentration suggests that the
Composite of PbS (Eg=0.41eV) with CdS (Eg=2.4eV).

A New Attack on NTRU Public Key Cryptosystem Depend on Using Public Key and Public Information

Abdul Monem S.Rahma; Qasim Mohammed Hussein

Engineering and Technology Journal, 2010, Volume 28, Issue 6, Pages 1061-1072

This paper proposed a new method to attack the NTRU cryptosystem [Hof00a,
Hof98b]. It tried to exploit the public information about the parameters of NTRU
cryptosystem and using the public key, to recover the private keys without delving
in the detail of encryption and decryption. It depended on extant knowledge about
the number of 1’s and -1’s in the private keys coefficients, f and g, which are
used in public key generation. It tried to make use of the polynomial that has
private key coefficients properties. The proposed attack was able to recover a
unique polynomial that represented the private key f and corresponding to private
key g, or their rotations. But, this attack remains expensive in time and depends on
the way of how to start in choice the permutation

Cement Kilns Dust Management In Iraq

Adnan A. Al-Samawi; Mohammed Ali I. Al-Hashimi; Sabah Obaid Hamad Al-Shadeed

Engineering and Technology Journal, 2010, Volume 28, Issue 6, Pages 1073-1093

Hundred thousands tons of cement kiln dust (CKD) as well as other emissions
are generated annually from existing cement plants in Iraq with significant
economic and environmental impacts. Therefore, an environmental sector plan
should be adopted to scrub the emissions and sound management of CKD waste
leading to save resources and secure better environmental quality are called for.
A survey was conducted and carried out covering all cement plants. Analysis of
data collected has shown that the production capacity was significantly decreased
to about 38 % on the average of the designed capacity. The consumption of raw
materials and fuel per unit production was increased by about 13 % and 23 %,
respectively. The amount of generated CKD is found to be variable among the
different cement plants. It can be estimated that the generated CKD on the average
is about (8-33) % of the production output depending on the conditions of each
plant.
This study serves to establish a factual basis to develop a convenient
environmental management plan for the cement industry sector. This study
proposes an environmental mitigation and monitoring plan to address the
environmental and social challenges to improve the environmental performance of
Iraqi cement industry sector.

Microstructural Modification of Al-base Composite by Friction Stir Processing

Nawal Ezzat

Engineering and Technology Journal, 2010, Volume 28, Issue 6, Pages 1094-1105

A novel surface modifying technique, Friction Stir Processing, is used to
enhance mechanical properties of Al-Si / Al2O3 composite, through micro
structural refinement and homogenization. The effect of processing parameters on
resultant microstructure and wear rate is investigated in this work.
The Friction Stir Processing resulted in significant breakup of the coarse Si
and Al-dendrites and uniform distribution of Si and Al2O3 in the matrix with
significant micro structural refinement. These microstructures changes lead to
significant improvement in wear resistance of composite

The Structural Properties of Thick Film of PbI2

Shatha Sh. Jamil; Ali M.Mousa

Engineering and Technology Journal, 2010, Volume 28, Issue 6, Pages 1106-1116

Polycrystalline layers of Lead iodide have been prepared using a solution growth
method on glass substrates for potential application to nuclear detection .This paper
reports on their preliminary characterization in terms of structural properties. The
influence of thickness and annealing on the structural properties has been
investigated.

Design And Implementation of Intelligent Soft- Start Controller For Induction Motor Controlled By VSI

A. J. Al-Shammerie; K. S. Krikor

Engineering and Technology Journal, 2010, Volume 28, Issue 6, Pages 1117-1127

This paper presents a practical implementation of the Fuzzy logic control to
an electrical drive system. The hardware control circuits are divided into two groups,
the first one is to determine the suitable trigger angle to the load according to their
windings resistance circuit. The second is to monitor the motor operation and runs in
order to compensate the trigger angle value when any disturbances occur at the motor.
The soft starters use the current through the stator winding of the motor as feedback,
in which the voltage is adjusted through the setting of the IGBT firing angle. The
feasibility and effectiveness of the control scheme are experimentally demonstrated
and the results are compared with the conventional soft starter controller in dynamic
responses of the closed-loop drive system.

Theoretical Aspects of some Mechanical Properties of Composites

Sabah S. AbdulNoor; Ahmad Al-Beiruti; Mustafa.H.Nashat

Engineering and Technology Journal, 2010, Volume 28, Issue 6, Pages 1128-1143

In the present wok, two mathematical models are constructed in order
to define the detailed nature of composite. The first one is based on the
classical Rule of Mixtures, (RoM) which is normally rotted from the ordinary
strength of materials. The second model is based on the theory of elasticity,
which deals with the detailed response of the internal macrostructure of the
composite. A virtual composite was assumed to be formed of a number of
matrices (Epoxy resin & Nickel) containing various inclusions (Carbon fibres
& powder, E-glass fibres & powder, and Kevlar fibres) in sequential
permutations. In general, the elasticity model E, exhibited various degrees of
superiority to the RoM depending on the mechanical parameters in question
and the mechanism by which it influences the internal details of the material.

Hûta Method for Solving nth Order State-Space Equations of Nonlinear Continuous-Time Control Systems

Atheer Jawad Kadhim; Raghad Kadhim Salih

Engineering and Technology Journal, 2010, Volume 28, Issue 6, Pages 1144-1159

The paper presents a proposed method with new algorithms written in
Matlab language to find the numerical solution of nth order state-space equations
(SSE's) of nonlinear continuous-time control system using Hûta method. The statespace
equation is the modern representation to analysis linear and nonlinear
continuous time invariant and time varying system. It was treated numerically to
the single-input-single-output (SISO) time invariant and time varying systems as
well as multiple-input-multiple-output (MIMO) time invariant and time varying
systems by using sixth-order-eight-stage Hûta method. We show that it is possible
to find the output values of nonlinear state-space model using Hûta method.
Finally, comparison between the numerical and exact results has been given with
illustrative figures for some test examples for solving different types of nonlinear
state-space equations using Hûta method for conciliated the accuracy of the results
of the proposed method.

Numerical Study of Solidification in Cavity with the Presence of Natural Convection

Wahid S. Mohammad

Engineering and Technology Journal, 2010, Volume 28, Issue 6, Pages 1160-1168

A study of Laminar two dimensional transient solidification with time –
dependent natural convection in the melt is carried out. The mathematical model
for the numerical simulation is based on enthalpy porosity method. The governing
equations are descritized on a fixed grid by means of a finite volume technique.
The (SIMPLE) procedure was adopted to solve mass, momentum and energy
equations for pure phase change material (water) placed in a cooled rectangular
cavity. The cavity was cooled from top alone, right side wall alone, and right side
wall with top and bottom walls together. In the case of top cooling a parabolic
shaped pattern of ice water interface was formed. For the right side wall cooling
the effect of density changes has led to an abnormal flow circulation which has
moderately modified the heat balance of the freezing interface causing a colliding
of cool and warm fluid layers. A density variation was seen in the freezing
interface region in most of the cases. The results obtained show good agreement
with experimental and numerical results of other researchers for pure convection
with small discrepancies in the ice interface. These discrepancies may be
attributed to the physical modeling used for water freezing.

Real Time Digital Speed Control System for DC Servo Motor Using LabVIEW 8.5 Package

Areej Alaa Hassen

Engineering and Technology Journal, 2010, Volume 28, Issue 6, Pages 1169-1185

This paper describes the design and implementation of a personal computer
based closed loop DC motor speed control system Using LabVIEW 8.5 Package
for data manipulation and interface control. Tuning the parameters of the PID
controller is done using trial and error method by conducting simulation on the
system model using Matlab package. This method is used to find the best system
response depending on the tuning parameters of the PID controller. These
parameters are then implemented in the designed real time digital PID controller
system based on LabVIEW package.
Carrying out the task of tuning the PID controller on the real time model requires
great effort and time consuming especially in the early stages. Thus the PID
controller tuning is firstly carried out on the simulation model in Matlab which is
time saving and gives close parameter approximation for applying in the real time
system directly. The PID control action in the real time system shows more
oscillation in comparison with the PID simulation control action. Simulation and
real time results for the speed control of the DC motor experiment were found to
have a high degree of agreement in maintaining the desired speed of the motor.

Study the Adsorption Phenomena of Phenol from Industrial Wastewater using Commercial Powdered Activated Carbon by using Isotherm Models

Khalid Farhod Chasib Al-Jiboury

Engineering and Technology Journal, 2010, Volume 28, Issue 6, Pages 1186-1195

Adsorption studies for phenol removal from aqueous solution onto commercial
Powdered Activated Carbon were carried out. Batch kinetics and isotherm studies
were carried out under varying conditions of contact time, initial phenol concentration,
adsorbent dose and pH. The adsorption of phenol increases with increasing initial
phenol concentration and decreases with increasing the solution pH value. The
equilibrium data in aqueous solutions was well represented by the Langmuir and
Freundlich isotherm models. Kinetics of adsorption followed a first order rate
equation. The studies showed that the Commercial Powdered Activated Carbon
can be used as an efficient adsorbent material for the removal of phenolics from
water and industrial wastewater.

The Inhibitive Effect of BTA on The Corrosion of Copper Rotating Cylinder Electrode in Oxygenated 0.1M H2SO4 Under Controlled Conditions of Mass Transfer

S. H. Alwash; I. K. Salih; Sh. A. Sameh

Engineering and Technology Journal, 2010, Volume 28, Issue 6, Pages 1196-1208

The inhibitive action of benzotrizole (BTA) on the corrosion of copper in
oxygenated 0.1M sulfuric acid solution has been investigated using the rotating
cylinder electrode to provide turbulent conditions. Potentiostatic polarization
measurements were carried out at different temperatures of 283,288,293 and 298K
and various speeds of rotation, 100,200,300 and 400 rpm.
In general, BTA, at concentration of 0.01M, effectively inhibits the corrosion of
copper in oxygenated 0.1M sulfuric acid solution. Moreover, BTA effectively
inhibits the anodic dissolution of copper and the cathodic reactions ,i.e., HER and
oxygen reduction reaction. Therefore, BTA acts as a mixed inhibitor in
oxygenated solutions.
The overall percentage of inhibition efficiency is about 98% . This indicates that
a Cu-BTA film is developed on the copper electrode surface which about 98% of
the corrosion rate . The overall inhibition efficiency is neither affected by the
turbulent flow rate , nor by the temperature increases.
The corrosion rate is temperature dependent only, which indicates that the
corrosion of copper in inhibited oxygenated 0.1M sulfuric acid solutions is under
activation control.

Preparing and Studying the Effect of HA and ZrO2 Addition on Fracture Strength of Dental Ceramic

Hussein Alaa Jaber; Sinan Salman Hamde

Engineering and Technology Journal, 2010, Volume 28, Issue 6, Pages 1209-1217

This work aims at preparing and studying the effect of hydroxyapatite (HA)
and zirconia (ZrO2) additions on some physical properties and fracture strength of
dental ceramic. In this work, dental ceramic batches have been prepared from
(80% Potash feldspar, 15% silica and 5% Duekhla kaolin). Firstly, HA was
added with different percentages (2,4,6,8,10)%wt. Secondly, both of HA
and ZrO2 have been added in percentage (5%wt) with different weight
percentages for both of HA and ZrO2 to (95%wt) of dental ceramic batch.
Mixes were semi-dry pressed under (15 MPa) load, and they were fired at
(1100°C) temperature. The results show the fracture strength of the dental
that ceramic increases with the addition of HA. The best addition of HA was
(4 %wt) because it gives the best of the physical and mechanical properties.
By the addition of HA:ZrO2 mixture, the value of fracture strength
increased more than the addition of HA alone.

Numerical and Experimental Investigations of Welded Butt Joints of (AISI304)

Muna. K. Abbass; Karima E. Amori; Rashaq A.Mohammed

Engineering and Technology Journal, 2010, Volume 28, Issue 6, Pages 1218-1240

Simulation of welding process (TIG or GTAW) of butt joint using finite
element analysis is presented. The base metal is ST(304). The numerical model
developed by include moving heat source, temperature dependent material
properties, phase change and transformation, and mechanical analysis. The
parameters studied numerically were welding current ranging between (80-150A)
depending on, welding velocity, plate thickness (2.5mm -5mm), and material of the
heat sink (carbon steel and copper). The numerical results show that increasing the
welding current with increasing of welding speed decreases the fusion zone area.
Using copper plate underneath the welded plates acts as a dissipation heat sink
which generates stronger heat gradient compared with carbon steel plate. The
experimental results show that increasing welding current leads to increasing the
micro hardness, and the microstructure becomes smaller. Due to increasing cooling
rate the microhardness have maximum value at the boundary between the Fusion
zone and heat affected zone.

Design and Simulation of A New Proposed Single-Slope Integrating Analog-to- Digital Converter System Based on Non-Linear Amplifiers

Azzad B. Saeed

Engineering and Technology Journal, 2010, Volume 28, Issue 6, Pages 1241-1252

In this paper, a unipolar single-slope integrating analog-to-digital
converter(ADC) is discussed, designed, and simulated, whereas, its conversion
time is less than that of the dual-slope integrating ADC.The proposed system
consists of logarithmic amplifier,anti-logarithmic amplifier, integrator, counter,
control logic unit and two timers stages.
The proposed design characterizes some of significant properties which
make it distinguished from the other previous designed systems, such as, it has
good noise immunity because of passing of the analog input signal through the
integrator circuit which it considered as a low pass filter. This system is capable
to convert an analog voltage of range of (0.0 – 0.6) volt using non-linear
amplifiers. At last, this system has very good forward linearity relation between the
output digital number and the analog input voltage value which is realized later by
theoretical calculation and simulation results.
This system is simulated and tested using software package Electronic
Workbench version V9, and one can see that simulation results approach to the
theoretical results, so for this reason, this system possesses acceptable design and
performance.

Shear Capacity of High-Strength Fiber Reinforced Concrete Beam-Column Joints

Kaiss Sarsam; Zaid Muhammad Kani Al-Azzawi

Engineering and Technology Journal, 2010, Volume 28, Issue 6, Pages 1253-1266

This work examines the work of 13 high-strength concrete (HSC) beamcolumn
joints (BCJ)-with and without steel fibers. Several shear design methods
(with modification for fiber content, where applicable) were found to be
conservative within a range of the following variables: 1) concrete compressive
strength, 2) type and volume fraction of steel fibers, 3) content of hoops in the
joint, and 4) column axial load. The coefficient of variation (COV) of the ratio
of test strength to design strength (VTEST / VrDES) was found to be appreciably low
for two of the five existing safe design methods. A conservative design method,
which lowers the COV even further to a value of 7.8 percent, is proposed for HSC
joints, with and without steel fiber reinforcement

Line Detection Using Radon Transform

H. H. Abbas; Hussein Ali Hussein

Engineering and Technology Journal, 2010, Volume 28, Issue 6, Pages 1267-1280

To extract features from digital images, it is useful to be able to find simple
shapes (straight lines, circles, ellipses, etc.).
In order to achieve this goal, one can be able to detect a group of pixels that are on
a straight line or a smooth curve. That is what a Hough transform is supposed to
do.
Since the Hough transform is a special case of Radon transform then line detection
process is accomplished using Radon transform.
In this paper, software for line detection using Radon transform has been designed
and implemented. Then the implemented software is tested under many conditions
and circumstances, the results are discussed, and many points are concluded from
the results.

Influence of Heat Treatment on Hardness And Microstructure of High Chromium Iron Alloy

Engineering and Technology Journal, 2010, Volume 28, Issue 6, Pages 217-228

This work deals with production of different sizes of grinding balls from high-
Cr-iron alloy . Cr contents range between (14-16) wt% carbon content (2.1-
2.4)wt% and Mo content (0.3-0.4)wt% ,those balls used in grinding cement and the
materials used in its manufacturing . Many heat treatments had been done on the
balls to show thier effects on hardness and microstructure. Balls of (70,80)mm
diameters were used in this work. The results show that after heating to (1000)c°
holding (90) minutes blast air cooling for given time and cold water quenched,
tempering at (400)c° for (4) hrs, still air cooling gave the best results in hardness
values with low retained austenite , And nearly the same results could be achieved
by oil quenching and the same tempering conditions.

Friction Stir Welding Of Porous Al-Si Alloy

Engineering and Technology Journal, 2010, Volume 28, Issue 6, Pages 229-243

The aim of this research is to study the ability of joining porous (Al-Si) alloy to
solid Aluminum using Friction Stir Welding Method . The porous alloy is fabricate
using casting method by adding(20,30,40) weight percent of Poly- athelin as space
holder materials. The welding process is done using different welding speed
(30,40and60)mm/min, with constant rotational speed (900) rpm.
Microstructure evaluation showed that it is possible to weld porous alloy to aluminum
in the solid state welding by friction stir process . Hardness test results showed that the
welding zone hardness is higher than that of welded materials, and the weld zone
hardness increased with increasing welding speed .The tensile test results showed that
the bonding strength increased with increasing welding speed at constant space holder
weight percentage, and it decreases with increasing addition percentage of space
holder.