Engineering and Technology Journal

Transient over-voltage caused by lighting, switching large inductive loads,
couples on to data communication or instrumentation signal lines and introduce
series fault alarm conditions and damage instrumentation electronics.
Most of the semi-conductor devices and other sensitive electronic
equipment are easily damaged with transients of high amplitude with fast rise time,
with threshold energy levels in the range of micro joules to mill joules. Hence, it is
very essential to protect the system by hardening the input power supply lines,
input/output data and communication lines utilizing various transient suppression
techniques to make the system immune to transients. If an electronic system
designer intend to build a protection circuit a custom design will be desirable, as
the interface or inter-connection could be more effective for the intended
environment

Wavelength division multiplexing (WDM) is a technology that enables the
transmission of several optical signals simultaneously at different carrier wavelengths
on a single fiber and the separation of the signals by wavelength at the receiving node.
While WDM is very attractive, it has some disadvantages also. One such
disadvantage is the appearance of fiber nonlinearities. With the use of multiple
channels, several miliwatts are injected into the fiber. Such high powers lead to the
appearance of different nonlinear effects in the fiber, mainly the Stimulated Raman
scattering (SRS), Stimulated Brillouin scattering (SBS), Four wave mixing (FWM),
and the Cross Phase Modulation (CPM). These nonlinear effects lead to the
degradation of system performance.
In this work the performance analysis of nonlinearities in the WDM systems was
implemented using Mat lab-(7).

Three selected bored piles executed at Basrah area were tested both by
static and dynamic pile test procedures in order to correlate their results when
evaluating the piles capacities. The correlation showed that the results are close to
each other in terms of load- settlement relations, but on the other hand, end
bearing capacity and skin friction values obtained by the dynamics tests are far
from the real behavior of piles. The reason may be due to lack of experience of
crew that supervises the dynamic tests. They have to practice more dynamic tests
and should build accumulated knowledge about the dynamic method of testing
piles. The time is still early for the dynamic tests to replace the classical static test
when evaluating piles capacities

AbstractT
he paper presents a proposed method with an algorithm which has been
written in Matlab language for designing a nonlinear key generator, which is
denoted by (US-TR), using unit-step function and trace function from Galois field
of order 2N (i.e. GF(2N), (N≥2)) to Galois field of order 2 (GF(2)). The proposed
generator produces a binary sequence of period (2N -1)where N is a composite
number, with high degree of complexity and good randomness properties. The
advantage of the new nonlinear generator is the output sequence which has high
degree of complexity to increase the security of this generator concerning the
designed feature that limit the ability of anti-jammer when it uses as a key in
cipher systems or in spread spectrum digital communication system. This paper
has useful properties of the trace function. Moreover, Illustrative examples are
given for determining the output sequence with its complexity of the proposed
generator and good results are obtained

Huge amounts of glass materials being applied in medical, pharmaceutical
and chemical aqueous solutions; this requires the study of chemical stability of
glass at the exposed surfaces with these solutions where the leaching takes place.
The leaching of the glass ions will transport these ions to the solutions
stored in the glass containers; leading to changes in the chemical composition in
the order of part per million that causes hazardous effect with time.
The present work investigates the leaching chemical properties of the
soda-lime Iraqi glass containers. The effect of the pH of contact solution and
annealing of glass on leaching rates is studied. Ionic leaching shows lower rate
with PH of the solutions at the ‘safe zone’: (6>PH>8.5). Annealing increases the
leaching rates and reduces of the chemical durability of glass. Increasing
annealing time led to further increase the leaching rate. In addition, the increase in
the exposed surface area also increases leaching rates.

The paper describes the results of theoretical study of the tilting pad bearing
consist of five pads each pad can be titling 0.2o about a cylindrical pivot at high
speed of rotating journal. The total oil film thickness includes elastic deformation
with thermal effect had been estimated. By using finite element method to solve the
Reynolds equation for dynamic load, from this solution generated pressure,
components of oil film forces and moments are expressed as functions of journal coordinates,
dynamic coefficients (stiffness and damping coefficients) these coefficients
of oil film can be determined by differentiation of the oil film force finally elastic
deformation of pad surface was obtained. This paper also includes the study of many
parameters such as pivot offset, preload factor, direction of load (load on pad and
load between load) and dynamic coefficients were presented as functions of
Sommerfeld number.
Results show that good bearing performance when the pad preload factor is increase
and pivot offset decreases.

This paper experimentally investigates the control of the heating process in a
water tank. A trial and error method is used to find the best system response depend
on the tuning parameters of the PI controller based on a Matlab simulation package in
order to replace these parameters in the real time digital PI controller system based
LabVIEW package. The PI control action in the real time system technique shows
more oscillation in comparison to that the PI simulation control action. Simulation
and real time results for heating process experiment has successful for maintaining
water tank temperature

As the practical importance of protection of industrial equipments from
corrosion the need arises to study the corrosion of different metals as Carbon steel,
Zinc and Copper measured their corrosion current and potentials have been
investigated in 3.5% NaCl solution at 40ºC for different flow conditions (Re =
5000, 10000 and 15000), by using commercial metal pipe as test specimens
cylindrical. Potentiodynamic polarization studies have been performed for single
metals. It was found experimentally that the corrosion of metals (Fe, Zn, Cu) is under
diffusion control since the corrosion current density (iL) increases and corrosion
potential (Ecorr.) shifts to less negative with increasing velocity, the limiting diffusion
current density is independent of the nature of the cathode material, but it depends on
the Reynolds number.
The corrosion current density of metals (Fe, Zn, Cu), shows a good agreements with
other works, and reasonable agreement with Culburn –Chilton and Paulson
correlations are also observed at different Re.No.

Most of the header information remains constant over the life-time of the
connection. For TCP connection many fields are constant and others change with small
values. To initiate compression of the headers of a packet stream, a full header is
transmitted over the link. The compressor and decompressor store most fields of this full
header as reference. The reference consists of the fields of the headers whose values are
constant and thus need not be sent over the link at all, or change little between
consecutive headers so that it uses fewer bits to send the difference from the previous
value compared to sending the absolute value.
To improve interactive response time and to decrease the header overhead on the system
we used the method of Compressing Protocol Headers (TCP/IP). Also it is used to
compress the HDLC header. The simulated communication protocols have been tested
between two PCs and the time delay, throughput and utilization have been measured

In a previous study, speed-controlled hydraulic motor system has
employed a DC motor for changing the swashplate angle of a variable
displacement piston pump. However, the speed control has been performed by a
flow modulation valve which is permitted to bypassing the flow of the hydraulic
motor when the speed exceeds the set value. In the present work, another speed
control configuration has been proposed with the pump and hydraulic motor are
permitted to perform reversal actions. The conventional proportional, integral and
derivative (PID) controller has been introduced to manipulate the speed error such
that it could achieve the required performance. The specification required by the
PID controller is to reach the command speed as fast as possible with minimum
peak overshoot. Also, the effectiveness of the suggested controller against
changing of system parameters is considered. The modeling of the speed control
system components is detailedly presented, including the dynamic of swashplate,
and one can easily see that the system is of a nonlinear nature. The state space
representation of the complete system has been developed and the program codes
are listed inside an m-file, which is instantaneously called by an s-function within
SIMULINK library.

Silica - mullite powder sieved through 100 mesh, mixed with graphite at
certain proportions and placed in a steel mould, then subjected to ≈ 40Mpa .After
air- drying for 24 hours the specimen buried in carbon and fired at 1150 ◦C
overnight. DC resistance was measured by the method of two probes. The
percolation threshold was not sharp , instead it starts from 10.5% graphite ratio up
to 21% were it resembles the conductivity of graphite alone . Resistance and
reactance analysis were carried out at three frequencies (0.55, 1.5, 5.0) kHz. The
specimen was subjected to heating/cooling cycle and the change in DC resistance
value (TCR) was found to be less than 1%for each 100◦C rise in temperature.

Electrochemical and photoelectrochemical etching technique have been
employed to produce nanostructured solar cell. Various preparation conditions
were examined. The I-V characteristics measurements were adopted to study
effects of these parameters on the solar cell efficiency. We found that when
shorter laser wavelength used to illuminate the porous layer during the etching
process, the conversion efficiency of the solar cell increases . While doping the
porous layer with phosphorous increases the nanostructured solar cell efficiency
by 30 %.

Molecular sieves type 13X was modified by treatment with saturated solution of
urea or thiourea and adding of sodium silicate as binder to give homogeneous
admixture in approximate weight percent, 20% urea or thiourea, 30% binder, and
50% MS13X. The samples were dried and shaped in cylindrical particles of about
5mm diameter and 4-8mm length. The FTIR studies show some interaction between
the added urea and thiourea with the original substrates. These are mainly hydrogen
band type interactions through –NH2 moiety with –OH group of framework oxygen in
the substrate or with adsorbed water. The urea displayed more significant interaction
with MS13X than thiourea. Molecular sieve 13X and its admixtures with urea and
thiourea showed good ability to remove phenol from water. The urea modified
sample, which has the largest surface area, was the best adsorbent for phenol
followed by thiourea treated sample. Excellent degree of phenol removal, greater than
98% was achieved by using 0.2 l/h flow rate of 10ppm phenolic solution and 56cm
bed length at 300C. The increasing of inlet phenol concentration in water affected
largely the driving force and the rate of adsorption, resulted also in higher capacities.
While the percentage removal of phenol was decreased by fixed other operating
conditions.

The HRF was studied by using pilot plant. This pilot plant was designed
and applied in Al – Wehda Water Treatment Plant which treats the raw water of
Tigris River in Al – Karradah in Baghdad city. Design characteristics of the pilot
HRF are 5.5m length × 1m width × 1m depth , the HRF length consists of inlet (
0.5 m ) , outlet ( 0.5 m ) and three compartments ( 2m , 1.5m and 1m )
filled with three different size of gravel ( 15mm , 10mm and 5mm ) respectively .
The HRF was continuously operated (24 h in a day) during the period from 15/
May / 2007 to 15/ July / 2007. Operated done in two stages. In the first stage,
raw water (free from any addition) was used, with three different flow rate 1.3, 1.1
and 0.9 m3/h. While in the second stage, coagulated water (raw water + alum) was
used, with flow rate 1.3 m3/h. To assess the performance of HRF, the required
tests were carried out. These tests are Turbidity, S.S, Temperature, pH and
Bacteriological tests. The results of tests were analyzed statistically. The mean of
removal efficiency of turbidity for first stage with discharges 1.3 , 1.1 and 0.9
m3/h is 92% , 94% and 95% respectively , and for second stage is 97% . These
results indicate the high performance of HRF in turbidity removal

A laser power comparator prototype that can be utilized in laboratories has been designed
constructed and tested. The system consists of three main electronic circuits: the laser comparator
electronic circuit, sign detector and phase inverting circuit, and an analog-to-digital readout
display circuit. The comparator has two detectors each receives a particular input signal. Two
input signals will be compared and the output will be displayed on a digital readout (or on an
oscilloscope). Power difference up to 0.1mW is achieved

This work is production of aluminum matrix composite by powder metallurgy
method .The samples have done when aluminum powder was used as a matrix in
purity of (9.99%) and silicon carbide(α-SiC) as reinforcement material, the particle
sizes were used which (125μm) at weight percentage (7.5% - 10% - 15%) from
silicon carbide for each particle size. The purpose is to improve the hardness and
wear properties of matrix .It was found that the hardness is increased with increment
of the amount of added particles, due to the hardness of silicon carbid particles.
From the wear test, it is found that the wear resistance increase with
increasing the weight percentage of SiC particles, but the wear rate increase when the
applied load increase for all the particles size and additional percentage.
Also, it is found that when the sliding velocity increases, the wear rate also
increases, but the best results were found in samples reinforced with (SiC) particles

Epoxy resin type (Ep-10) was used as a matrix for composite materials,
with Glass fibers, aluminum powder and silica powder as reinforcement with
volume fraction (Vf= 30%). Four types of composites were prepared:-
(1) Epoxy reinforced with glass fiber and aluminum powder.
(2) Epoxy reinforced with glass fiber and silica powder.
(3) Epoxy reinforced with aluminum powder.
(4) Epoxy reinforced with silica powder.
Research subject was implied studying some of mechanical properties for
composite materials that used in the research, in different weathering conditions
including Ultraviolet Radiation (UV).

According to the lack of water in AL-Khadimiya town due to the sabotage
justify happened in the infrastructure of town like water distribution system of
potable water as a result the residents of the concerned town used the ground water in
all life activities as second source.
13 sampling wells have been chosen in that area ,4 sample collected from Tiger river
each sample represented different area around AL-Khadimiya and chemical study
included for the soil of different depth to examine their water .
The experimental works at the laboratory shows the increase in Turbidity
value .Hardness of calcium and magnesium, chloride, sulphat &Bacteria account
(Coli form) the high values of the pervious testes made water an portable and with
respect to the irrigation of plants, it is accepted with medium salt &Chlorides, the
spiel result at the laboratory tests for the Tiger river is not acceptable for drinking not
for irrigation is accepted.

The sulphate problem in fine aggregate increases with time in Iraq and the
construction companies became face a lot of difficulties to find fine aggregate
within the specification with regard to sulphate content. This paper studies the
possibility of adjusting fine aggregate content in concrete mixes to facilitate using
fine aggregate with sulphate content higher than the Iraqi specification limit
(0.5%), but the total sulphate content of the mix will be within the specification (I
Q S 45, 1984). One reference mix is used in this study with fine aggregate
conformed to the specification for sulphate content ,and three other mixes are used
with different fine aggregate content and also different sulphate content .Some
tests are conducted for these produced mixes to fined their mechanical properties.
This study shows the ability of using fine aggregate with sulphate content up to
(2.33%) to produce mixes with a compressive strength ,splitting tensile strength
,and modulus of rapture not less than (80%),(94%), (84%) respectively as
compared with the refrence mixe at age of (180) days .
Keywords : Internal sulphate in concrete ,sulphate in fine aggregate

The aim of this research to use extracted natural pigments which extracted
plants such as chlorophyll as plasticizer and stabilizer material by simple method. The
sample of rubber was prepared with adding different percent from chlorophyll
pigment (0-25)pphr to study the effect of this material on properties of natural rubber.
When we added chlorophyll pigment, we fined chlorophyll act as plasticizer that
interact between rubber chains and decrease interaction molecular forces that
decrease specific gravity (from 0.997 to 0.986), tensile strength (from 13.295 to
8.384)MPa, modulus of elasticity (from 2.745 to 1.312) MPa. This mean is
chlorophyll pigment is doing as lubricant material to facility the moving of molecules
chain one on anther and act as stabilizer that protect rubber from UV light because it
absorbed UV light and transmit it to no harm heat .Therefore this work exists with a
good replacement for synthetics plasticizers and stabilizers materials avoiding their
toxicity and their highly cost.