Engineering and Technology Journal

Induction heating system has a number of inherent benefits compared to
traditional heating systems. Many analytical and numerical approaches have been
applied to solve the problem of induction heating; efforts are made to introduce
new development in computational approaches and utilization of newly developed
specialized software packages to improve the methods of analysis and design of
induction heating systems. This paper includes the description of the steps used for
developing a general and comprehensive program, which works under ANSYS
11.0SP1 package environment. This program can be applied to analyze a wide
range of induction heating applications according to finite element method.
Analysis approach is extended to deal with induction heating systems with
magnetic material workpieces by introducing the multiregion method. Results of
analysis the induction heating systems, by using ANSYS package, include all the
electromagnetic and thermal quantities related to the induction heating process. To
approve the simulation, used in this work, the results were compared with
published practical measurements, a good agreement was achieved

The term "eutrophic" refers to system rich in nutrients, and hence Eutrophication
means nutrient enrichment, particularly by increasing levels of nitrogen and
phosphorus [1]. In lakes, phosphorus is generally regarded as the limiting nutrient for
primary production [2] implying that increasing phosphorus concentrations will result
in increasing production of phytoplankton and benthic algae. Excessive amounts of
phytoplankton cause low Secchi depths and may consequently wipe out the benthic
flora by shading the light [3]. Toxic cyanobacteria tend to bloom when nutrient levels
are high [4]. Apart from being a nuisance in their own right, settling phytoplankton
may cause anoxia in hypolimnetic waters as their decomposition consumers oxygen
[5], and this may result in extinction of the benthic fauna [6] and fish feeding on such
animals. Altogether, these Eutrophication effects threaten the foundations of aquatic
ecosystems. The low oxygen levels in hypolimnetic waters associated with
Eutrophication may also cause mobilization of phosphorus in the sediments, thus
inducing a feedback mechanism where already high nutrient levels increase even more

Gearing is one of the most critical components in mechanical power transmission
systems. This work investigates the characteristics of an Involute gear system
including contact stresses. Current methods of calculating spur gear (Non-linear
Analysis), contact stress using Hertz’s equation, which were originally derived for
contact between two cylinders. To enable the investigation of contact problems with
Finite Element Method (FEM), the stiffness relationship between the two contacts
areas is usually established through a spring placed between the two contacting areas.
This can be achieved by inserting a contact element placed in between the two areas
where contact occurs. A computer program was built up using (MATLAB 6.5). The
results of the two dimensional FEM analyses from ANSYS are presented. These
stresses are compared with the theoretical values (Hertz’s equations). Both results
agree very well. This indicates that the Finite Element Method(FEM) model is
accurate. The results of contact stress analysis indicates that increasing the geometrical
parameters (Pressure angle, number of teeth and module) lead to improve the tooth
contact stress, with the contact position, because the increasing of the geometrical
parameters will results in an increase of the tooth stiffness which leads to decrease the
tooth contact stress.

Photo-ions of rubidium were generated due to the interaction of effusive Rb
atomic beam with the C.W. UV lamp of 2.5 KW power. The photo-ions isotopic
of (Rb85 & Rb87 ) were extracted and analyzed by a quadruple mass filter. The
measured photo-ion current was 28 x 10-13 Amp

The object of this study is to find a construction solution to the problem of
expansive soils by suggesting of a new shape of the conventional footing which
has a sharp edge, this footing is named a “wedge footing” which is considered as
an alternative shape to the strip footing to dissipate the swelling pressure
produced in the soil when inserting the footing in it. These soils have a tendency
to absorb water and expand causing high damage to the lightly loaded buildings
and structures. The analysis carried out using finite element method to assess the
behaviour of displacement of the wedge footing compared with strip footing
which is considered as a basic problem. An equation is obtained from the results
of the computer package of “STATISTICA” based on the results of finite
element analysis related to the displacement of wedge shaped footing as a
function of soil properties and footing with coefficient of regression of
(R2= 98.9%).

In this investigation the individual component models for a typical subcritical
cycle are developed based on the best published theoretical and empirical
literature. The developed approach, especially for air conditioning systems, is
conceptually new and can be used with modification to a variety of multicomponent
system applications. The component models are then integrated and
the model predictions validated against the data from various experimental test
systems.
A variable speed compressor test rig was used to obtain the experimental data
to be compared with the results predicted from the system model. The
experimental data was monitored from the start-up of the system until the
achievement of its steady-state. The system approached its steady-state after 270
sec and 360 sec for compressor speeds of 900 rpm and 1200 rpm respectively.
The system disturbance was imposed by changing the operation conditions for
each component. A comparison between the experimental data for these
disturbances and theoretical results shows a good agreement with a discrepancy of
about (5%). The model can be used as a basis for the design, performance and
efficiency of a vapor compression systems.

This study presents three-dimensional finite element analysis to the behavior of
composite concrete-corrugated steel cylindrical shell. This type of construction
utilizes the advantages of both of ordinary reinforced concrete and the composite
action of cylindrical shell with corrugated steel plates. The 8-node brick elements
in (ANSYS v.9.0) have been used to represent the concrete, while the steel bars
are modeled as discrete axial members connected with concrete elements at shared
nodes with the assumption of prefect bond between the concrete and the steel bars.
The corrugated steel plate is modeled by four-node shell elements. The interface
elements are modeled by using three-dimensional surface to surface contact
elements connected with the nodes of concrete and steel channel elements.
Comparison is made between the results obtained from the finite element analysis
and the available experimental results of previous studies

Steganography and cryptography are usually used to ensure information
safety in today’s data communication. This paper makes use of audio
steganography technique and encrypted secret sharing to increases the security
level of hidden data. The proposed schema can hide digital data in audio file; the
resulted stego audio file is separated then into 2- shares encrypted random secure
images, which can be transmitted or distributed separately over an threaten
communication channel. Using multilevel of security techniques increases the
security level of hidden data, and makes it more robust to attack since secret data
is not hidden in one cover media but it is separated across two images, that they
will be encrypted and appear completely random

The present study describes the results of experimental and numerical investigation of
wet steam flow in low-pressure convergent-divergent nozzles and deals with the effects of
turbulence on the process of homogeneous condensation. The experimental investigation
consist mainly the axial pressure distribution of a fixed nozzle test section. The mathematical
model that described the droplet nucleation and the growth rates combined with the field
conservations was treated numerically within the CFD code FLUENT 6.3., in which the
computational domain is discretized in a general unstructured mesh that is locally refined
especially in the area of the spontaneous nucleation zone. The equations describing droplet
formations and interphase change are solved sequentially after solving the main flow
conservation equations. The calculations were carried out assuming that the flow is twodimensional,
compressible, turbulent and viscous. The aimof the present study is the use of the
modified k-ε model for modeling the turbulence within an unstructured mesh solver. The
results obtained from the numerical part of the current analysis are compared with the
experimental results and gave an acceptable agreement. Also present experimental and
numerical results showed good agreements with numerical and experimental existing
published data.

Two major problems arise when concrete is exposed to elevated
temperatures. One is the deterioration in mechanical properties of concrete and the
other problem is spalling of concrete. In recent times, the inclusion of
polypropylene fibers had been reported to be a feasible method to prevent spalling
of concrete subjected to elevated temperature. Additional problems arise due to the
fact that by adding polypropylene fibers, the residual properties of heated concrete
may be adversely affected. The essential objective of this work is to investigate the
effect of incorporation of polypropylene fibers or/and steel fibers on the residual
properties of lightweight concrete made from porcelinite aggregate after subjected
to elevated temperatures. The concrete specimens heated to target temperatures of
100, 200, 400, 600 and 800 oC, at a rate of 10 oC per minute. When the target
temperature was reached, the specimens were kept at that temperature for 2 hours
and then allowed to cool to room temperature by natural cooling. For each type of
concrete, compressive strength, splitting tensile strength, static modulus of
elasticity, and thermal expansion strains were determined before and after exposing
the concrete to the target elevated temperatures. Experimental results indicated that
polypropylene fiber-reinforced LWAC showed more reduction in its residual
mechanical properties compared to plain LWAC. These different are more
pronounced at exposure temperature of 200 and 400 oC. Average differences of
30,25 and 20 percent were observed in static modulus of elasticity, splitting tensile
strength and compressive strength respectively, for specimens heated up to 400 oC.
The addition of steel fibers inside the polypropylene fiber concrete would improve
the residual mechanical properties of heated concrete at temperature range 200 to
600 oC. On average, the improvement ranged from 9 to 20 percent

Grillage method is used here to determine girder distribution factor (GDF).
STAAD Pro. 2006 program is used here to represent grillage and solving for (GDF).
Different GDFs are adopted by AASHTO LRFD based on the National Cooperative
Highway Research Program (NCHRP) 12-26 and the results compared with formulas
given by AASHTO Standard. Three different composite steel bridge superstructures
are considered with girder spacing (1.22, 2.44 and 3.66 m). To compute GDF in the
considered bridges subjected to one truck, the vehicle is placed on each bridge such
that the load effect in the girders is maximized. If compared with Finite element
method, the modified grillage was found to be simple, efficient and having practical
accuracy in the analysis of bridge decks in determining GDF factors.

In this paper a new approach is proposed for enhancement of the data
transmission optical communication systems by applying CDMA technique based
error detection and correction code. This paper includes the study and analysis of
the different important variables for optical CDMA system, and focuses on
increasing the system performance by selecting the optimum values for different
variables to reduce the multiple access interference problems and also by applying
error detection and correction code with selecting of the best polynomial. The
detected and corrected code technique is more active because the selection of the
optimum values from the variables network helps to decrease the interference
sources and noise to lower value. The selection of optimum values helps in
reducing the number of the added correct bits in the transmit code word
consequence enhancement of the system performance because the channel is
exploited to transmit the information. The results show enhancement in system
performance when selecting optimum value of received power (2μ Watt), where
the enhancement ratio is equal to (23%). Also this paper proves the use of error
correction technique became very active with the optimum values of received
power (2 μWatt), so the improvement ratio with applying ECC is equal to (22%).

Artificial neural networks (ANNs) with back-propagation algorithm are
performed for predicting the stage of Tigris River in Qurna city, Basrah, south of
Iraq. This model was adopted to investigate the applicability of ANNs as an
effective tool to simulate the river stage for short term. By using the neural
network toolbox in Matlab R2007b, three models are constructed as the first
experiment. Multilayer percpetron with one hidden layer is used in the
architecture of network. The best model is selected according to the trial and error
procedure based on three common statistic coefficients (coefficient of correlation,
root mean square error, and coefficient of efficiency). The best model from first
experiment is used to predict the stage river for one, two, and three days ahead as
the second experiment. Results indicated the ANNs with back-propagation
algorithm are a powerful technique to predict the short term stage of Tigris River

In this paper, a secure data hiding method is introduced. It increases the
security of embedded data through combining between the steganography and
cryptography. First, the secrete message is divided into blocks with same size
according to length of key stream that is generated using nonlinear key generator.
This key is used to encrypt the first block in secret message using the stream
cipher, whereas the other blocks are encrypted depending on the behavior of
cipher block chaining (CBC) mode that turn on the stream cipher in order to
guarantee no duplicated encrypted blocks. In our CBC mode the current ciphertext
block will became a key stream to encrypt the next plaintext block, and so on.
After encryption stage complete, the encrypted massage are embedded randomly
in bmp image using LSB insertion method to increase the security

Variable speed wind turbine generators are more powerful than constant
speed turbines. However the unstable wind speed causes the variable speed
machine to have variable voltage and frequency.
The quality of power can be improved if a suitable control technique is used
in the system, the fluctuating wind generator output needs to be controlled, for
this reason one needs to study the dynamic characteristics of the combined wind
generator system.
Better control design can be designed for more dynamic performance. Blade
pitch control of the fan is discussed here in this research by using rotary
potentiometers for position control and some tests is done in control laboratory
as a simulation of the position control.

A two stage preparation method of foamed glass is described here aiming
to achieve reproducibility and convenience. Fritting of the solid components
assembles the first stage; where firing a mix of the frit, foaming agents and the
liquid component gather the second stage. Almost uniform cellular structure of the
foamed glass is achieved at relatively low firing temperature of the mix (820°C for
10 min). The cellular structure is enclosed with a shell of continuous surface.
Physical properties (density, porosity and water absorption) are measured
for the product along with the mechanical properties that concerns production of
building blocks, namely impact and compression strength.
The flexibility of the presented two stage preparation method simplifies
future attempts to modify its properties to adapt particular applications.

Pneumatic systems are widely used in industrial automation for their
advantages such as speed of motion, low cost of maintenance, safe operation and
high power/ weight ratio, cleanliness, simplicity of operation as compared with
other systems such as hydraulic and electro - mechanical technologies.
In this work, a fuzzy PI controller is designed for improving the output
displacement of the servo pneumatic system, in order to improve the position
transient response. The aim of tuning is to reach minimum steady state error
in the output displacement and also to compensate the effect of applying
different types of external load forces. The parameters of the controller are tuned
using a trial and error method.
A comparison between the results of using Fuzzy PI controller and the
PID controller showed that the Fuzzy PI controller has improved the
maximum error ratio in position up to 45 % by adding a fixed external
load force and up to 19 % by adding variable external load force with high
compensation for the effects of any external load force.

In this study, a nonlinear three dimensional finite element analysis has been
used to conduct an analytical investigation on the behavior of curved in plan
composite concrete-concrete beam using the analysis system computer program
(ANSYS v.9.0 2004).
Various types of beams, with available experimental results are chosen to
check the validity and the accuracy of the adopted models. In general good
agreement is obtained. The maximum percentage difference in ultimate loadcarrying
capacity is 12%. Parametric studies are carried out to study the influence
of the curvature (L/R ratio of 0, 0.1, 0.15 and 0.2) on the behavior of the curved in
plan composite concrete beams. Also, some important material and solution
parameters that affect the structure behavior are studied. These include the slab
thickness, support condition, compressive strength of concrete and the percentage
of steel across the interface between the stem and the slab of the composite beam

The producing composite materials of dual reinforcement in which the matrix
material is aluminum reinforced with two types of ceramic particles : which are
Alumina (50μm <63μm) by Die Compaction method Samples prepared and fired at
( 500 0C ) show the best wear resistance when the mixing ratio is ( SiC 12.5wt% ,
Al2O3 12.5wt% ), where density is ( 2.5479 g ⁄cm3 ).The wear test was carried out
under conditions of load and linear speed variation

The development in production of curved sections in one forming process
using direct extrusion process is going to increase annually because of increasing
demands on such sections that are used in car body construction and railways .This
research aims to find a new method for design of non-symmetric dies ,that can
extrude a curved product by one pass of extrusion and by controlling the material
flow through the deformation zone of the die .The (F.E.M) and (U.B.M) were used in
designing the non-symmetric dies so that the lower and upper die angles are different.
The simulation of metal flow during the extrusion process, stresses and strains
distribution in the bullet, friction factor and the die angles on the bending or
eccentricity of the product were found. The extrusion pressure and the power
consumption during the process were also found using both (FEM) and (UBM)
methods. The results have shown that :
The bend of the product using non-symmetric dies is always towards the small die
angle. It has been also shown that the amount of bent or the eccentricity of the