Engineering and Technology Journal

This work focuses on studying the role of drying and calcination on
stiochiometry and crystallinity of deposited HA. Also, studying the effect of sintering
temperature on phases generated, physical and mechanical properties of sintered HA
powder compact at a range of (800-1200) ˚C.
Both Ca/P ratio and crystallinity were increased after calcination, where the Ca/P
ratio raised from 1.7 to 1.9 and the height of Hydroxyapatite peak intensity was also
increased .Secondary phases also appeared.
X-ray diffraction patterns and electrical microscopic pictures of polished surfaces
of the Hydroxyapatite compact after sintering had revealed the process of
densification and crystallization of Hydroxyapatite . The increase of sintering
temperature leads to grain growth, while surface cracking and other defects became
lower i.e. porosity and surface voids.
Both hardness and fracture strength were increased for samples sintered at high
temperatures where they reached their maximum values at sintering temperature
(1200)ºC .The maximum linear shrinkage was 20% at sintering temperature 1200ºC.
The maximum bulk density was (2.173) g/cm3 at sintering temperature of 1200ºC
and the maximum apparent density was (2.58) g/cm3 at sintering temperature 900ºC.
The maximum apparent and open porosities were 47.136% and 47.058% respectively
at sintering temperature 900ºC. The maximum water absorption was 39.13% at
sintering temperature 800ºC.

The main purpose of this work is to propose an approximate method to solve
integral equation with multiple time lags (IEMTL) namely least squares method
with aid of Chebyshev polynomials of (first, second, third, and fourth)kinds.
Example is given as an application of least squares method with aid of four kinds
of Chebyshev polynomials

The study of gas flow in unsaturated soil is important for better modeling of
volatile organic compounds (VOCs) transport. A gas flow in unsaturated soil can be
induced naturally by the atmospheric pressure fluctuation. Oscillations in barometric
pressure are both diurnal, corresponding to daily heating and cooling of the
atmosphere, and of longer time periods, resulting from the passage of weather fronts.
Daily variations will average about 4 to 5 mbar while those due to weather front
passage can be 25 mbar or more.
A one-dimensional conceptual model was used to investigate the advective
gas flow zones in the subsurface induced by the natural atmospheric pressure
fluctuation. From analytical solution, it is clear that the gas phase inside unsaturated
zone moves with sinusoidal velocity whose amplitude decrease with depth. Two zones
can be distinguished. First in which the gas phase can reach the soil surface and
continuously mixed with clean air. The depth "Penetration Depth" of this zone may
range from 0.05m to 0.8m. Second is "Oscillation Zone" in which the air oscillates
around its original position but still remains in the soil. Maximum air displacement
toward the upper boundary may reach 0.24m when the depth of the lower
impermeable boundary is 10m. This displacement is more as the lower impermeable
boundary is deeper. The mixing of air above penetration depth with clean air above
soil surface and the oscillation of air below penetration depth may have a significant
effect on natural VOCs transport and fate in the soil region within these depths

This research work presents a nonlinear finite element investigation on the
behavior of lightweight reinforced concrete beams. This investigation is carried
out in order to get a better understanding of their behavior throughout the entire
loading history.
The three-dimensional 20-node brick elements are used to model the
concrete, while the reinforcing bars are modeled as axial members embedded
within the concrete brick elements. The compressive behavior of concrete is
simulated by an elastic-plastic work-hardening model followed by a perfectly
plastic response, which terminated at the onset of crushing. In tension, a fixed
smeared crack model has been used .The effect of some important parameters
(ƒ'c , rw ,a/d) have been investigated to study their influence on the predicted loaddeflection
curves

The set of all n×n non singular matrices over the field F form a group under
the operation of matrix multiplication, This group is called the general linear group
of dimension n over the field F, denoted by GL(n,F) .
The subgroup from this group is called the special linear group denoted by SL(n,F).
We take n=2 and F=2k where k natural, k>1. Thus we have SL (2,2k).
Our work in this thesis is to find the Artin's exponent from the cyclic subgroups of
these groups and the character table of it's.
Then we have that: a SL(2,2k ) is equal to 2k-1

The purpose of this work is to study, analyze, and design a half-bridge seriesparallel
resonant inverter for induction heating applications. A pulse width modulation
(PWM)-based double integral sliding mode voltage controlled buck converter is
proposed for control the induction heating power. This type of controller is used in
order to obtain very small steady state error, stable and fast dynamic response, and
robustness against variations in the line voltage and converter parameters. A small
induction heating coil is designed and constructed. A carbon steel (C45) cylindrical
billet is used as a load. The induction heating load parameters (RL and LL) are
measured at the resonant frequency of 85 kHz. The parameters of the resonant circuit
are chosen for operation at resonant. The inverter is operated at unity power factor by
phased locked loop (PLL) control irrespective of load variations, with maximum
current gain, and practically no voltage spikes in the switching devices at turn-off,
therefore no snubber circuit is used for operation at unity power factor. A power
MOSFET transistor is used as a switching device for buck converter and the IGBT
transistor is used as a switching device for the inverter. A complete designed system is
simulated using Matlab/Simulink. All the electronic control circuits are designed and
implemented. The practical results are compared with simulation results to verify the
proposed induction heating system. A close agreement between simulation and
practical results is noticed and a good performance is achieved.

The current study concerns an investigation of diffusion mechanism of
different kinds of water into thermoplastic material (typeunplasticised PVC,
(UPVC)) that is often used as pipes for healthy draining purposes and other
services.
After preparation of samples from this material, they were immersed in glass
containers which contain (sea water, river water, rain water, distilled water, and
tap water), the weights of these samples are measured at periodic time of soaking.
The aim of this work is introducing an idea about the diffusion behavior and the
penetration of water through the material under study, then, the values of diffusion
coefficient (Dx) are evaluated for each type of water mentioned above.
After comparing the obtained results from these tests, it is found that the distilled
water has the higher value of (DX) into the (UPVC) material, it is followed by the
sea water and then the rainwater, while each of the river and tap water record the
lowest values.

Speed and complexity are two important properties in the block cipher.
The block length of the block cipher controls these two aspects. The speed
limitation enforces the designer to build block cipher system as hardware
prototype. In the same manner, the key complexity aspect acts as increasing the
block length, which will cause the increasing of complexity. In this paper, a
proposed block cipher algorithm will be presented. Which includes non-linear
function with new random key generators to generate all keys and a new approach
for S-box is used in this algorithm.

Epoxy-phenol system were prepared and studied before and after reinforcing with
glass fibers (woven roven 0ο-90ο direction) with volume fraction (vf = 48%). The
samples irradiated with uv radiation with wave length (λ= 320 nm), irradiation energy
(1.5 watt/ cm2) for 50 hours. The dielectric constant and thermal conductivity
measured for all samples before and after irradiation with uv radiation. The results
showed that the increasing percentage of phenolic resin in the blends decreasing the
dielectric constant and thermal conductivity of all samples before and after irradiation
with uv radiation. While the results before irradiation showed the effect of glass fibers
in increasing the dielectric constant and thermal conductivity. Finally the results
showed that the dielectric constant decreased, thermal conductivity increased for all
samples after irradiation with uv radiation

This study was carried out to investigate the effect of the chemical
treatment of banana fibers on the physical properties of composites. Banana fibers
were treated with 10% sodium hydroxide and some physical tests were carried out
like: dielectric strength, dielectric constant, and thermal conductivity. The results
were compared with untreated fibers composites and virgin unsaturated polyester.
The results showed that the chemical treatment improved the dielectric strength
and thermal conductivity by about 29.37% and 139% respectively compared with
untreated fiber composites. Finally, the dielectric constant value of the treated
fiber composite was found to be lower than the untreated fiber composite and
virgin unsaturated polyester

Changes in the crystalline domains caused by heat treating Mylar films
between Tg to 240 oC have been studied by Fourier Transform Infrared
spectroscopy (FTIR) and X-ray Diffraction (XRD). Prior to glass transition
temperature, shrinkage in the film is insignificant, but progresses rather abruptly
as melting point is approached bringing the smooth film surface to rather wrinkle.
The absorbance increase in the FTIR spectra is due to the thickened film caused
by shrinking rather than the improvement in the crystalline orientation. XRD on
the other hand show that heat treatment of the film near melting point only reduces
the contribution of the crystalline domains in the direction [100] in favor of other
direction namely úû
ù
êë
é110
_
rather than on the account of loosing order in favor
of the amorphous regions

This paper studded the effect of symmetry mapping process on the
compression parameters of the fractal color image compression by moment
features was studded. Feature of moment utilized to reduction the symmetry
mapping from 8 to only one. The operation of reduction is achieved by using
predictor to symmetry mappings; the predictor will predict specific symmetry
mapping according a specific feature of moments to one of eight. Such that eight
versions (blocks) are produced for each domain block, so this case needs 8
mappings and it requires more computational time. Our suggestion will directly
reduce the encoding time 1:8 times

BaxSr1-xTiO3 (BST) ferroelectric nano, poly crystalline systems were
processed with three concentrations (x = 0.5, 0.7 and 0.9) using a technique known
as oxalic acid route. The XRD spectra were analyzed, and used Scherer formula to
estimate the crystallite size of the products, which reached to 15.4 nm at x = 0.5. It
is found that increasing of Sr+2 cations help to decrease the crystallite size of
BaxSr1-xTiO3 system and the tetragonality c/a increases when the crystallite size
increases. In physical tests we conclude that the oxalic acid method is a good
method to prepare a BST ferroelectric phase with high density (5.05, 5.5 and 5.45)
gm/cm3, and small porosity (16, 8, and11) % for (x = 0.5, 0.7 and 0.9)
respectively

Fluidized beds are characterized by high heat transfer rates between the
bed and internal surfaces and have uniform temperature distribution that can be
achieved in fluidized bed systems. In the same time there is a chaotic behavior of
hydrodynamic and heat transfer in gas-solid fluidized bed.
Experimental work was carried out in gas-solid (air – sand) fluidized bed to
investigate the steady state heat transfer coefficient. The bed column used was
(172) mm in diameter and (1000) mm height, fitted with immersed cylindrical
heating element of (25.4) mm in diameter. The fluidizing medium was air flowing
at different velocities from fixed bed to fluidized bed of (0.006-0.078)m/s, and
three different sizes of fine sand particles were used (i.e. 63, 112, and 145 μm),
these average particles diameters were estimated by two methods (Wide and
Narrow Range Solids).
A comparison have been done with values of the minimum fluidizing velocity that
calculated analytically, empirical, and which got experimentally. The results show
a chaotic behavior of hydrodynamic gas-solid fluidized bed.
The heat transfer coefficient and the bed viodage increase with increasing gas
fluidizing velocity and the heat transfer coefficient decreases with an increase in
particle diameter.
Two empirical correlations are proposed which can calculate wide range solids and
narrow range solids based on experimental data. The Nusselt number presented
with some dimensionless groups as follows:-
For Wide Range Solids Nu = 0.81Re0.94 Pr0.35
Where the correlation coefficient (R) was equal to (0.92) and the average absolute
relative error was (12.62 %).
For Narrow Range Solids Nu = 0.45Re0.65 Pr0.33
Where the correlation coefficient (R) was equal to (0.86) and the average absolute
relative error was (24.2 %)

A multiband printed dipole antenna is presented for use in wireless
communication applications. The proposed fractal antenna design is based on
fractal geometry of the second level tent function transformation. Due to the
resulting geometrical structures of a fractal tent function curve depend on the
starting angles of the initial tent function, many dipole antennas have been
modeled and the corresponding radiation characteristics have been evaluated.
Theoretical performance of these antennas has been calculated using the method
of moments (MoM) electromagnetic simulator, IE3D. Simulation results of many
tent fractal dipole antennas which have been modeled show that all of these
antennas have multiband resonate behavior, but this resonate behavior is different
according to the starting angle for each antenna. The results have shown that these
antennas have acceptable performance for VSWR ≤ 2 (return loss ≤ -10 dB),
using a 50W feed line, at most of the resonating frequencies. This feature provides
antenna designer with more degree of freedom, and makes the proposed antenna
(or its monopole counterpart) suitable for use in the modern multi-functions
communication systems.

Thermal And Flow Fields Due To Laminar Free Convection In An Isosceles
Triangular Enclosure Having Thick Conducting Sidewalls Have Been Investigated
Computationally. Inclined Left And Right Side Walls Are Maintained At
Isothermal Hot And Cold Temperatures Respectively While The Bottom Wall Is
Considered Adiabatic. Problem Has Been Analyzed And The Non-Dimensional
Governing Equations Are Solved Using Finite Volume Approach And Employing
More Nodes At The Fluid–Solid Interface. Triangular Enclosure Is Assumed To
Be Filled With An Air With A Prandtl Number Of 0.7. Rayleigh Number Varies
From 103 To 106 Where The Flow And Thermal Fields Are Computed For Various
Rayleigh Numbers. Consequently, It Was Observed That The Stream Function
And Temperature Contours Strongly Change With High Rayleigh Number. The
Streamline And Isotherm Plots And The Variations Of The Average Nusselt
Number At The Hot Left And The Cold Right Side Walls Are Also Presented. The
Results Explained A Good Agreement With Another Published Results

The removal of Cd(II) onto granular activated carbon (GAC) and kaolinite in single
component systems has been studied using batch adsorption. Batch adsorption studied were
carried out under various amount of GAC and Kaolinite, Cd(II) ion concentration, pH and
contact time. The experimental data was analyzed by Langmuir, Freundlich and Redlich-
Peterson isotherms. The equilibrium adsorption capacity of Cd(II) was determined from
Langmuir isotherm equation and found to be 3.002 mg/g for GAC and 1.837 mg/g for
kaolinite. Pore diffusion model for batch adsorption is used to predict the concentrationdecay
curve for adsorption of Cd(II) onto GAC and kaolinite.

Simulated annealing (SA) has been considered as a good tool for search
and optimization problems which represent the abstraction of obtaining the
crystalline structure through a physical process. This algorithm works sequentially
that the current state will produce only one next state. That will make the search to
be slower and the important drawback is that the search may fall in local minimum
which represent the best solution in only part of the solution space. In this work
we present the transformation of Simulated Annealing algorithm into quantum
version which will be called Quantum Simulated Annealing (QSA). This
algorithm will overcome the drawbacks of slowness and local minimum falling by
produce as much as possible of the neighbor states and work on in parallel by
exploiting the massive parallelism feature in quantum computation. The results
show that QSA can find the optimal path in smaller number of iterations than the
sequential simulated annealing algorithm and the time complexity of QSA is
better than any other parallel simulated annealing algorithm.

The aim of this research is studying some physical properties (bulk density,
apparent density, apparent porosity percentage, water absorption percentage) for
metal matrix composite material. Aluminum matrix consists boron carbide particles
as a reinforced phase. Different percents (0%, 2%, 5%, 10%, and 15%) of (B4C)
have been used. powder technology process is used for preparing the specimens,
the results shows that the bulk and apparent density decrease, apparent porosity
percentage and water absorption percentage were increasing as percentage of (B4C)
particles increase.

In this study, thin films of CuO were deposited on glass substrates using
thermal laser evaporation technique. The structure characterization of the film was
carried out with XRD. The results of XRD show that all samples have a
polycrystalline .The optical measurements on the deposited films were performed
to determine the transmission spectrum and the absorption coefficient as a
function of incident wave length. Then from the optical parameters, extinction
coefficient, dielectric constant with two part real and imaginary part, value and
type of energy gap, type of the dominant absorption processes, real and complex
refractive index as functions of incident photon energy, were determined. The
energy gap is found to be equal to 1.8 eV for CuO that is direct transfer . This
results is agree to the results given by other researchers. Then thin films annealed
thermal rapid by using halogen lamp .The annealing influence very much to thin
film by addition an enhancement to the thin films.