Journal of Engineering

Reinforcement of refractory castables with steel fibers improves their strength for cracking and
spalling and expands the service life.
The results show that raising the temperature from 700C to 900C causes an increase in porosity
and decrease in bulk density for refractory castables. This happens because of decomposition of the
hydraulic bond of alumina cement.
When the temperature is raised higher than 900C , ceramic bond is formed as a result of sol d
reaction between alumina cement and bauxite aggregate. This leads to reduction of the porosity ar d
increase the bulk density. Steel fibers are affected positively in reducing the porosity ar d
increasing the bulk density for refractory castables. This positive effect increases with in*ease n
the fibers contentup to 1..5%.
All castable samples have good spalling resistances at all temperatures for different percentage of
steel fibers.
Improvement of reinforced refractory castables increases with rising temperature of firing, but it
was not possible to raise the temperature above 1000"C because of the oxidation of the steel fibers.

Production of Wet crude oil has been a growing field problem worldwide. Applications of the methods and technologies to treat wet crude oil are needed to solve this problem and remove as much water as is economically possible. This paper deals with laboratory test to evaluate the relative efficiency of different emulsion breakets (de-emulsifiers) under different conditions.
Five de-emulsifiers were used to treat wet crude oil from East Baghdad and Kirkuk oilfields. On the
basis of a laboratory study, it is shown that using RP6000 (commercial) and NIPD de-emulsifiers
achieved the best results; the latter was introduced in the present work. The de-emulsification rate is
inlluenced i:o a great extent by the de-emulsifier concentration.
Finally, it is shown that water *in-oil emulsions formed from kirkuk crude oil (low viscosity's and
asphaltenes content) are less stable and more easily broken than those from the more viscous and highly asphaltenes, East Baghdad crude oil.

This research deals with the stress analysis of typical underground tunnels using isoparametric finite
elements. Enhanced soflware is used for predicting and analyzing this behavior by using a single
phase formulation. This software was developed from an original Computer code named MIXDYN
The finite element method is used to solve the dynamic equilibrium equation with step-by-step time
integration schemes. A selected type of dynamic load was chosen which is blast loading.
Frictional and paniculate materials, i.e., concrete and soil, are considered. The soil and concrete structures arc analyzed where a dynamic elastic model for concrete and a linear elastic one for soil
are used. The soil is further analyzed by a bounding surface plasticity model. The stress waves
travel and the reflection effects especially in the no tension materials, i.e., soil are investigated.
The effects of blast loading are then analyzed hypothetically placing the explosion at the ground
surface. The stresses and displacements are computed at different sections.
The nonlinear analysis utilizing the bounding surface plasticity characterization gave better
predictions over the linear elastic model. The linear elastic model is proposed to be used as a first
prediction of the problems encountered, but it is incapable of realizing the actual behavior under
dynamic loads.

Rotating turbine blades are the important parts in gas turbines. Hence, an accurate estimation of
stresses, deformations and vibration characteristics are required in the design to avoid failure and \'o
obtain an optimum weight and cost. Because in recent years interest in the effect of temperature c n
solid bodies has greatly increased, thermal effects are investigated in addition to the rotation rl
effects.
This work presents the numerical solutions of the blade using degenerated curved shell theory, \\
finite element package has been developed using the degenerated curved shell element as a
discretization element in order to obtain the stresses, deformations and vibration characteristics r,f
the rotating blades. The numerical results are compared with experimental and theoretical results :n
the published literature and they showed good agreement.

The (P.E.) values reveal a similar seasonal variation .for six selected climatological stations over
Mujib basin\' The average annual values ranges between 2200 mm in the SE region to 1400 mm for
the NW and SW regions of the basin. The relation between the long-term average values and the
climatic parameters (Class A p*, Temperature; Wind, Sun Shine duration % RH %) for three
climatological stations were determined using the linear regression equations. High correlation
coefficient values suggest that the obtained equations are highly reliable. Mujib basin is divided into
three climatic zones : Moisture index > -80 where the water balance for this zone shows water
surplus during Dec. to Feb. and water ieiicit during March to November. Moisture indexes range
between -80 to -90 where the water balance for the normal and wet water years show water surpli.s
in this zone during the wetted months. Moisture index < -90 where the water deficit is experienced
in high degree and no water surplus has been observed.

This paper describes a stego system in which a gray scale image is embedded in another one.
Wavelet transform of both the cover image and the embedded image is used to sort their subbands
energies to guarantee that the embedded image will be inserted in the low frequency components cf
the cover image with little perceptual distortion.
Embedding by this way increases the robustness of the system but affects the system
imperceptibility, so a variable scaling factor (a) is used to attenuate the components of the
embedded image before adding them to those of the cover image.
It is found that the stego image with peak signal-to-noise ratio (PSNR) of about 30 dB has gool
imperceptibility.
The attacker is proposed to be active, so compression is applied to the stego image. According to
this, the scaling factor must be increased to compromise between the quality of the stego and the
reconstructed images. This increment reduces the imperceptibility of the stego image and here the
trade off between the imperceptibility and the robustness occurs.
The attack is proposed to be stego known, so that to increase the security of the system, a stego key
is generated from the embedded image itself and is transmitted separately, making the system type
secret key qteganography.
The size of the embedded image obtained in the work is one quarter the size of the cover image that
may be considered good comparing with the available systems.

Semi-analytical solution for the resistance of the flow and convective heat and mass transfer over
the surface of ellipsoidal bubble and a drop were obtained. The fluid flow solution utilized the
viscous dissipation and the heat transfer solution was based on the integral method. New relations
for the drag force and the convective heat and mass transfer coefficients were derived and compared
with the available theoretical solutions and experimental correlations. The range of Reynok s
number was from I to 100 and Weber number from 0 to 3.23.

Image quality and geometric accuracy of SPOT data are essential elements in cartographil
applications. The evaluation of geometric accuracy of SPOT data is carried out by analysis-an l
quantification of the errors in geometric correction. For this purpose, many programs are design l
to correct the image geometrically (polynomial transformation) and to calculate the root mean
square error (RMSE) by the standard method.
The standard method of calculating the R.MSE is shown to be capable of providing accurate
estimates of geometric error when a modest number of control points is available
(between I 0- 1 5 points). This method also provides an indication of the effects bf choosing different
polynomial orders.

This work presents procedures to utilise the finite element results of magnetic flux density vector
to create animation tile which displays rapidly successive frames, prepared by postprocessing
,leading to the effect of moving flux to the viewer .The method is applied to 2-D transformer
model showing excellent animation effect of the alternating flux in both the core area and the
leakage flux area. The method is useful in analysis as the dynamic flux monitoring gives more
details than static display. The method can be used to produce instructional materials giving the
student an impression of the natural behaviour of the electromagnetic devices.