Al-Nahrain Journal for Engineering Sciences

The current ACI code and many other codes
permit the moment magnification method for
design of slender reinforced concrete (RC)
columns. Manually, the design/analysis
procedure is tedious, so that the codes state a
pre-prediction if the column is slender or not.
In other words, before starting design codes
provide slenderness limits to be considered to
decide whether a column is slender or not.
This work will concentrate on the slender RC
column provisions of the latest ACI Code.
Using this method some columns are found to
be short. In the proposed method of this work,
it is found that some of these short columns
are found to be long , thus needing moment
magnification. Since column analysis/design
represents dealing with one of the most critical
parts of RC buildings, this proposed
magnification is presented in this work.

The city of Baghdad is located in the central
Mesopotamian plain of the Twin Rivers.
According to the geological surveys, the whole
area is covered by recent sediments of alluvial
origin, deposited by successive floods of Tigris
and Euphrates rivers, and by wind action.
Since Baghdad city is the capital it surrounded
by network of industrial areas for different
purposes and this, affect the environment.
Solid wastes generated from both animal and
domestic sources can significantly impair
drinking, irrigation, recreational water, other
water sources and soil in rural and urban areas
therefore it must be monitored and controlled
very well to protect the wild life and
environment and this represent the goal of
research tool used for this purpose is remote
sensing and Geographic Information System
(GIS) due to their ability of monitoring and
analyzing large amount of data. The techniques
demonstrated in this research include
procedures for developing regional spatial data
into a coordinated GIS database, characterizing
and identifying wildlife habitat, quantifying
and assessing land use change, pollution due to
changes in land use and demonstrating the
application of these GIS and modeling
methods for assessing cumulative
environmental effects associated with landuse
change.
Geographic Information System (GIS) and
remote sensing techniques are used to monitor
the environment in Baghdad city especially the
industrial waste. Using GIS and remote
sensing techniques in the environmental
assessment give a quick and low cost.
Preliminary investigation can be considered as
aiding tools to the traditional and detailed
investigation procedures.

The experimental and analytical behavior of
various mixes of roller compacted concrete
(RCC) using different materials is presented in
this work. This work is divided into two groups
of experiments.
In the first group a reference mix was prepared
using local materials (cement, sand, aggregate).
Mechanical and dynamic properties of reference
mix with and without admixtures have been
obtained. Also, this series includes a study of the
various variables affecting the mechanical and
dynamic properties of RCC.
In this work, the effect of cement content,
water/cement W/C ratio and type of aggregate on
the mechanical properties has been studied. The
optimum mixes which have good properties
obtained from the first group of study were used in
the second group.
In this work, the effect of admixtures and type of
admixtures (steel filings, metakaolin, fly ash, lime,
rice husk and concrete wastes) on the mechanical
properties has been studied.
The analysis of results showed that using steel
filings improves the mechanical properties when
replacing the sand by steel filings in (5, 10, 15 and
20) % by weight. The ultimate compressive
strength at 7 and 28 days is higher by 13.2 and
24.7%, respectively, than the compressive strength
using sand only. Partial cement replacement by
mineral admixtures like metakaolin with (10, 20
and 30) %, lime with (4, 6, 8, 10, 20 and 30) %, fly
ash with (10, 20 and 30) % and rice husk with (4
and 8) % decreases the strength and other
properties at early age of 28 days by about 12.02%
when using metakaolin by 20% and about 12.5%
when using lime by 10 %.

This research involves the effect of both
vertical and horizontal spacing, as well as the
length of the reinforcing strips, on the
structural behavior of a model reinforced soil
retaining wall.
The tests were carried out on a small-scale
laboratory model, in which uniform graded
sand was used as a fill material. It was placed
at a high dense state; raining technique was
used for this purpose. The sand was reinforced
with thin dipped Aluminum strips. The size of
these reinforcing strips was chosen sufficient
enough to prevent rupture mode of failure. The
retaining wall was presented by a plastic
transparent sheet. The results showed that the
horizontal spacing is more significant
parameter on deflection of the wall as
compared to the vertical spacing of the
reinforcing strips. The critical values of the
horizontal and vertical spacing with respect to
this research were 20 and 10 cm respectively.
A short length of reinforcement proved to
cause appreciable deflection of the wall, even
under close horizontal and vertical spacing.

The absence of universally accepted
solutions in the structural concrete codes for
the design of reinforcement in shells gives rise
to the problem of calculating the required
reinforcement in these structures. The constant
development of the computer s performance
and storage capacity combined with the
powerful numerical methods reveal the need
for a standard procedure to design shells
subjected to membrane and flexural forces.
In this paper, the solution for the design
of the required reinforcement in concrete shells
is presented based on a complete iterative
computational algorithm to design shell
elements subjected to combined membrane
forces and bending moments.
In the design equations, the reinforcement
will contribute to tension and the concrete
compression struts parallel to the crack
direction will contribute to compression. The
reinforcement is assumed to have two
orthogonal layers placed in the top and bottom
surfaces with appropriate covers. Each
reinforcement layer has reinforcing bars placed
orthogonally. For the concrete compression
struts, the stress is assumed to be uniformly
distributed This design algorithm is achieved by
developing a design code (DRCSH) based on
a complete iterative computational algorithm.
This program can be used as a stand-alone
version, to determine the load carrying
capacity of critical points in reinforced
concrete panels, plates and shells; and to verify
the design code on the element level, five
experimental models are designed. The
designed elements give calculated ultimate
strengths from 7 to 18% higher than test results
values, except one model, which confirms the
adequacy of the design algorithm, and the
developed design code.

Some of the electric networks adjacent countries
are linked to either the alternating current lines or
to direct current lines, that is really depends upon
the geographic distance of the linking points and
the amount of the used current. In view of rapid
and huge increasing of electric power
consumption and to shorten the value of losses
inside transferring operation besides the electric
system steady. Accordingly and due to all we
have mentioned the direct current transmission
has been established in high voltage for long
distance. These lines can be used when the linking
points are far- off, and when the frequency for the
two required systems are different. Therefore
transformation stations are being used at both
ending sides to transfer from alternating to
direct current and vice-versa. Also a (HVDC)
system can be constructed according to stages in
proportion with the voltage development and the
load requirement. There is always the need to
maintain the transformation voltage at ultimate
possible value in order to have a high efficiency
operation. In this paper the transmission line was
represented by using MATLAB program for two
different lengths (300,600) Km & different firing
angles then comparison is held between these two
lengths according to efficiency & economical
view.

There is an increasing demand for higher
data rates and higher quality in wireless
communications that has motivated the use of
multiple antenna elements at both the
transmitter and the receiver sides of a wireless
link. Space-time coding (STC) deals with the
design of good codes of multiple antenna
wireless systems.
A new proposed orthogonal code
is designed and presented in this paper as an
improved design of delay diversity for
multilevel space time coding with multiple
inputs and multiple outputs. The code is based
on using two signals transmitted at different
rates in order to remove the problems that
appear from different types of fading due to
multipath channel and to reduce intersymbol
interference (ISI) between the symbols.
The transmitter and the receiver are designed
to encode and decode the proposed orthogonal
code through the frequency selective and flat
fading channels. Time invariant rapidly
varying fading channel is included ; that the
path gains change for each symbol. The
detection is non coherent STC that neither the
receiver nor the transmitter knows the channel
propagation coefficients. Quasi-static fading
channel with coherent STC is also included,
that only the receiver has knowledge of the
channel through training symbols is available
at the beginning of each frame of the receiver.
The method gives coding gain, diversity gain
as well as the design of the proposed code for
three or four transmitting antennas with low
complexity.

Macro- and microscopic levels of analyses
are used to capture the behavior of a built-in
beam made of a unidirectional fiberreinforced
polymeric material. Finite element
formulation basing on the displacement
approach and minimum potential energy
principle is carried out in the longitudinal
direction of the beam to determine the
vertical displacements (deflections) at
various sections, stresses and strains. A unit
cell method in micromechanical analysis
based on the finite element method is used to
define the state and distribution of the
stresses induced in transverse sections.
Hexagonal fiber-matrix packing system is
idealized for the problem. The package of
ANSYS 5.4 and a Matlab program are used
to solve for the macro- and micromechanical
analyses. To examine the validity of the
presented method, it is applied to analyze a
beam made of matrix and fibers with the
same elastic properties the results are then
compared with those obtained by using a
method used for isotropic materials given
that properties , the convergence noticed is
verifying the validity of the analysis method
adopted by the current work.

This paper describes the first part of the
development of a non-linear finite element
simulation of the friction stir welding process;
it is concerned with thermal analysis. A
transient, three dimensional, non-linear thermal
model with moving heat source was
developed. Also a steady-state, three
dimensional, non-linear fluid-thermal model
with stationary heat source was developed.
Differences of results for both models were
discussed. Results of both models were
compared with experimental work. Transient
thermal model results appear to be more
reliable as compared to the CFD approach.

This work includes the application of a pack
cementation of germanium-doped aluminum
and silicon coatings on low alloy steel type-
T21 yields a significant improvement in the
oxidation. Steel-T21 was coated with
germanium-doped aluminzing-siliconizing.
Diffusion coating was carried out at 1050 oC
for 6 h under an Ar atmosphere by
simultaneous germanium-dopded aluminizingsiliconizing
process. Cyclic oxidation tests
were conducted on the coated steel-T21 alloy
in the temperature range oxide 600-800 oC in
air for 30 h at 5 h cycle. The results showed
that the oxidation kinetics for coated system in
air was found to be parabolic .Oxide phases
that formed on coated system are SiO2 and
Cr2O3..Mthamatical model using MATLAB
show that there is multiple linear model for
oxidation kinetics.

The application of a pack cementation of
Y-doped chromium and silicon coatings
on low alloy steel type-T22 yields a
significant improvement in the oxidation
resistance. Steel-T22 was coated with Ydoped
chromizing-siliconizing. Diffusion
coating was carried out at 1050 oC for 6 h
under an Ar atmosphere by simultaneous
Y-dopded chromizing-siliconizing
process. Cyclic oxidation tests were
conducted on the coated steel-T22 alloy in
the temperature range 300-500 oC in H2O
for 100 h at 5 h cycle. . The oxidation
kinetics for coated system in H2O was
found to be parabolic .Oxide phases that
formed on coated system are SiO2 and
Cr2O3. Finite element results show that
there is a good agreement

The economical design of plate loaded by
pressure can be obtained by using stiffeners
instead of increasing the thickness of plate.
The main subject of this work is to obtain the
effect of stiffener height on the maximum
stress in the plate subjected to pressure load.
Different plate-stiffener sets are selected to
find the effects of stiffener thickness, plate
dimensions and pressure, on the optimum
stiffener height. The models under
consideration are square plates clamped rigidly
from four edges.
Finite Element method is used to analyze
160 different models by using the Finite
Element software package ANSYS version 11.
Another analysis method based on maximum
stress equation is used to analyze 30 models.
The graphical comparison of results between
two analytical methods is presented by a
figure. It is found that the numerical results
obtained by Finite Element Analysis converge
to theoretical results.
The optimum height of stiffener under
above different effects is found. The critical
pressure curves for square plate dimension sets
are also presented.

The importance of penetration and
perforation in to targets in both military and
civilian applications has made it the subject of
many investigations. But the bulk of these
investigations was experimental rather than
analytical or numerical because of complexity
of the governing equations. Hence most of the
existing models are either mathematically
rigorous or so simplified that they neglect
many important parameters. Moreover, weight
and cost are among the most important
consideration in the design of perforation
resistant systems (containment shields).
Therefore, the present investigation has
focused on the perforation and penetration of
relatively thick metallic targets by rigid
cylindro-ogival projectiles. To achieve the
experimental part of this work a locally
manufactured compression device was built
for this purpose where the target plate was
subjected to biaxial compression load of about
0.6 of its buckling load. A life 7.62 mm
ammunition with steal projectiles have been
used to impact the targets at 400 and 600 m/s
thus the exit velocity in terms of the impact
velocity and the total work done at the target
was derived for the case of biaxial
compression. Comparison of the experimental
and the analytical results showed a good
agreement while targets in the state of
compression showed about 80% improvement
in penetration resistance.

Tread of the tire is occasionally dislocated due
to sever running on the road. Retreading is
necessary in this case, and retread rubber
compounds are made from a blend of NR/BR by
using several additives like Activator Accelerator
such as Zn salts of high molecular fatty acid
(LAUREX) & homogenizing agents (Struktol-
MS) produced by Uniroyal, Delayed Action
Accelerators type Thiazoles and Sulfenamides
such as (AMAX & MORFAX) produced by
Vanderbilt.. insoluble sulfur, Pine Tar and
others.
An infinite number of rubber recipes are
possible in blends. The best properties of each
components are selected to achieve a blend
having a wide spectrum of properties
(recommended for retreading compounds) which
is superior to that of the individual component
and also economically competitive. The effect of
using different levels(0.6,0.65,0.85pphr) of
accelerators such as (AMAX & MORFAX) are
enhancing the phsico-mechanical
properties(tensile strength, modulus,shore
hardness and abrasion resistance index), and the
Activators Accelerator (LAUREX & Struktol-
MS) in the rubber compounds are evaluated in
such away that LAUREX is more affective in
recipe no.3(2.5pphr) than the same level of
Struktol-MS, so that it is making use of preparing
suitable retreading rubber compound

The present work is concerned with the
preparation of polyurethane elastomers.
Polyurethane elastomer was prepared by the
bulk polymerization via one
4,4'diphenyl methane
polypropylene glycol
using stannous octeate as a catalyst.
The operating conditions of the polymerization
were studied and their affects on the
mechanical properties of the prepared
elastomer.
with
4,4'diphenyl methane diisocyanate to
equivalent of polypropylene glycol (NCO/OH)
(1.5-
3), and curing temperature of about
mechanical properties of polyuretha
elastomers were:
Kinetic of the reaction also was studied using
adiabatic temperature rise method. The overall
order of reaction was
of the reaction was
frequency coefficient of reaction (
(mole/g mixture)
Introduction
most successful materials for solid tires that
are used for military and industrial
applications. This was one of the first large
scale applications for polyurethane elastomer.
Many important advantages of polyurethane
tires can offer over n
such as higher mechanical properties, ease of
production, and have higher load bearing in
addition to the long lifetime and reducing the
overall cost.
containing significant number of urethane
1stRegional Conference of Eng
vol.11, No
of NCO
M.Mohammed
Ass.Prof
1441957ka@yahoo
100 grams of po
0.1 ratio of catalyst was used with
-
Under these conditions, the
The tensile strength
MPa).
Hardness
Elongation
Modulus of elasticity
9 MPa
mixture)-0.5
Polyurethane elastomer
Polyurethanes (PU) are the polymers
Regional No.3, 2008
NCO/OH on the Mechanical properties of
Polyurethane Elastomers
yahoo.com
one-shot method of
diisocyanate (MDI) with
(PPG) and
polypropylene glycol
Hardness, shore A
% (
MPa).
1.5, the activation energy
(40 KJ/mole
S-1) .

In this paper, the processes of 3D LASER
scanning and dimension inspection were simulated
for certain dimensions object. The scanning
operation is divided into two major modes,
Searching Mode and Scanning Mode. In scanning
mode two sub-processes (scanned point validation
and plane fitting) are introduced, i.e. to find the
plane which contains most of scanned points. The
final step is the decision making, which gives a
decision about acceptance or rejection of the
scanned manufactured object. The proposed
algorithm is successfully applied to seven cases.
One of them which has the exact dimensions and
this case has been accepted. The other six cases,
which have different dimensions, have been
rejected.

This paper proposed a technique of
bit-rate control for video streaming over
constant bit-rate communication channel,
where the MPEG-2, standard variable bit-rate
(VBR), is adapted to be used as a constant bitrate
(CBR). The target image quality and
output rate of the video encoder is controlled
by feedback based on the buffer level. A CBR
transport over networks, result is a good
performance compared with that of VBR. It
introduced simplicity of network monitoring
and analysis, where the VBR video streaming
over CBR channel can be adapted to avoid the
problem of congestion of the network. This
paper studies the important issue of adapting
VBR-compressed video for transport over a
CBR channel. The developed systems are
implemented using Matlab (Ver 6.5) under
Windows XP operating system.

In this paper, Raman amplification
characteristics in photonic crystal fibers
(PCFs) are investigated in details. Performance
comparsion between PCF-based Raman
amplifier and other conventional fiber-based
counterparts is presented. The simulated results
reported here can be used as a guide line to
design PCF-based Raman amplifier that
outperforms the conventional fiber amplifiers.
Raman gain as high as 33 dB can be obtained
with a well designed PCF even at low pump
power of 300 mW.

Synovial joints form the most important
feature of the human body as they represent the
centers of the most essential and basic activity
in the human beings, which is motion. Starting
from the role that are played by the lubrication
regimes in effectiveness and maintenance of
the joint this study was initiated. It investigates
the lubrication systems that are operative in
synovial joint. Depending on the loading
conditions and sliding velocity during one gate
of the walking cycle the profile of the synovial
film thickness and the pressure developed in
the knee joint when the hydrodynamic and
elastohydrodynamic lubrication regimes are
operative was determined.
For the hydrodynamic and elastohydrodynamic
lubrication analysis a mathematical model
obtained by solving the governing equation
using numerical methods. Results showed that
for the hydrodynamic action the minimum film
thickness determined was between (0.365-1.8)
μm and the pressure developed ranged
between (20.6-860.449) kN/m2. While for
elastohydrodynamic action the minimum film
thickness ranged from (2.5-3.57) μm and the
developed pressure ranged between (97.68-
146.5) kN/m2. Finally, it was shown that in
specific conditions hydrodynamic and
elastohydrodynamic lubrication mechanisms
gave a good explanation to how the joint
functions.

In this study we introduce a solution for wound
healing controlling therapy by using a
monochromatic pulse diode laser light 650 nm,
50% duty cycle and 1 MHz.
Many studies proved last years a positive
effect of diode laser light application in wound
healing process.
In this paper we study the effect of time
illumination parameter on healing process. For
this kind of therapy, a 650 nm diode laser used.
Its original electronic circuit drive was
improved to give pulsed output laser of 50%
duty cycle, 1 MHz.
Twenty male mice, three months old were
usd in this study (photo-biostimulation). The
wound was made on bilateral back sides of
each mouse, two sessions of illumination
carried everyday for 12 and 18 minutes during
15 days time. This study was compared with
our previous study set for 5 minutes for one
session therapy in 1st and 2nd day of healing
process.

The aim of the study is to evaluate the Von
Mises stress distribution of different human
teeth model. Three-dimensional model of the
maxillary central incisor, mandibular first
molar and mandibular central incisor were
constructed using Auto CAD (Auto CAD
2007) software and then imported to ANSYS
software (ANSYS V.10) to get finite element
model of each teeth. A loading simulating the
200N force was applied vertically and with
different inclination to the crowns. Then same
loading was applied vertically but the load was
distributed along the incisal area for the
incisors and at occlusal margin for the molar.
Finally the crown was considered as porcelain
material and the vertical load was distributed
along each tooth and the Von Mises stresses
were calculated. The results showed that the
increase in the loading angle from 0°, 26° to
45° resulted in an increase in tooth Von Mises
stress which means increase the probability of
tooth failure. When the load distributed along
wide region the ability of model to fail for the
same loading will be decreased. Also when the
crown consider as porcelain material there will
be increasing Von Mises stress compare with
the enamel crown