Al-Qadisiyah Journal for Engineering Sciences

Extrusion, among other types, is one of the most important forming processes
due to its high productivity, lower cost and its good ability to improve the physical and
mechanical properties of extruded materials. FE simulation was carried out on ABAQUS
software ver.6.9. to study the distribution of stress and temperature which created through
the extrusion process. The results of present study are accentuated that, there is a
complicated relationship between stress and temperature distribution relative to die angle
and friction coefficient. It was found, in the range of tested cases, at friction coefficient of
more than ( 0.08 ), for ( 45o
) die angle, the maximum value of temperature is twice higher
than that of ( 75o
), hence the die angle has more significant effect on state of stress and
temperature than that of friction coefficient. Nevertheless, a high die angle ( α = 75o
)
emerged low value of maximum temperature due to easily flow of material toward the die
orifice. Furthermore, there are a gradual increasing of vonMises criterion and temperature
with increasing the friction coefficient while they are decreasing with increasing the die
angle.

— In this work, a staircase patch microstrip antenna with slots is proposed to
cover the 2G/3G/4G cellular mobile base station bands, when the antenna is excited with
a transmission line, creates several modes these modes are composite to obtain a large
bandwidth. The proposed antenna operates in the band from 0.86 GHz to 4.78 GHz with
an impedance bandwidth of 138%. The use of staircase patch antenna is to achieve more
attractive performance such as wider bandwidth, better impedance matching and better
radiation. Inserting different slots to the patch of the antenna to enhance the gain and
return loss. The gain is obtained ranging from 2.18 dBi to 5.3 dBi. Good radiation
efficiencies ranging from 70% to 97% is achieved

This paper mainly uses ANSYS V.15 , the finite element analysis software, to
make nonlinear analysis of reactive powder concrete deep beams . The models simulating
the test process were established, the calculation results of ANSYS are compared with the
experimental results. Data of eight RPC deep beams tested by researchers were used for
comparison with ANSYS models .Furthermore three parametric studies were carried out by
changing the size of opening , location of openings and CFRP systems configuration . The
comparison shows that ANSYS analysis results are similar to experimental results (the
maximum difference in the ultimate load was less than 7.5 %), which indicates ANSYS
analysis software can be used to simulate the mechanical property of reactive powder
concrete structures

The process of separating nickel from the waste of thermal power stations
has a positive effect on the environment and has a good economic return. . In this
study, nickel was separated from the wastes of the South Baghdad thermal power
station by using phosphoric acid. The investigation studied the influence parameters
( concentration of acid, temperature, time, size of waste granules and acid to the
waste quantity ratio) on separation process of nickel. The best conditions in the
separation process were obtained when the concentration of acid is 5 molarities, the
temperature 50 °C, the duration time of separation is 4 hours, the acid phosphoric to
the waste quantity ratio is 30, and the size of the waste granules is 150μm. The
percentage of nickel that can be separated from the wastes of south Baghdad thermal
power station reaches 81%

when the steam turbine-generator is connected with series of compensation along the
transmission line, the sub synchronous resonance may happen. The Flexible Ac Transmission System
(FACTS) controller of the devices wide use which has been used to reduce and suppress the
phenomenon of sub-synchronous resonance the Thyristor Control Series Compensation (TCSC) and
Static VAR Compensation (SVC) are the types of FACTS controller that has been used to put down
the SSR and also for the purpose of provide a better and efficient solution to improve the transferred
capacity system to connect the series compensation along the transmission line. Series capacitor work
to increase the chance of creating sub synchronous resonance. Series capacitors also have an
inclination to amplify the shaft stress during considerable network transien toccurrence, SSR
phenomena happen which can cause damage of the shaft generator turbine. The first standard model
of IEEE was adopted to study this phenomenon. This research deals the PID control of SVC( Static
VAR Compensation) and TCSC (Thyristor Controlled Series Compensator) and excitation system
controller for reducing SSR in power system. In this research, the method of Eigenvalue was used to
analysis the sub-synchronous resonance phenomenon and the result was verified using DYMOLA
simulation

The heat sink with vertically rectangular interrupted fins investigated numerically
in a natural convection field, and with steady-state heat transfer. Numerical study has
been conducted using ANSYS Fluent software (R16.1) in order to develop a 3-D
numerical model. The dimensions of fins are (305 mm length, 100 mm width, 17 mm
height, and 9.5 mm space between fins). The number of fins used on the surface are
eight. In this study, the heat input that is used as follow (20, 40, 60, 80, 100, and 120
watts). The study is focused on interrupted rectangular fins with different arrangement of
fins. The results show that the addition of interruption fins in various arrangements will
improve the thermal performance of the heat sink, and through the results, a better
interruption rate obtained as an equation

Natural materials that are readily available in large amounts in nature and
easily accessible may be used as low cost additives. The aim of this study is to measure
the susceptibility of these locally available materials, conocarpus plant, to improve the
quality of wastewater discharged from textile industry.
In addition to conocarpus plant, carbonized conocarpus and activated carbon were used
as adsorbents in order to make a comparison, and to test which one of the three types
give the best efficiency for removing dye. The ability of adsorbents to adsorb dye was
studied using batch system; studied parameters were effect of pH, dose of adsorbents,
time, and agitation speed. The experimental results showed that the maximum removal
efficiency of conocarpus was found to be 87.5% at 50 rpm mixing speed, pH value 3 ,
mixing time 120 min and the dose of adsorbent was 0.25 g. The maximum removal
efficiency for carbonized conocarpus was up to 98.7% at 150 rpm mixing speed, pH value
3 , mixing time was equal to 7 hours and the dose of sorbent was 1.25 g. For activated
carbon the maximum removal efficiency was found to be 99% at mixing speed of 200 rpm,
pH value 3 or 11, mixing time was equal to 7 hours and the dose of the sorbent was 1.25
g. The above removal efficiencies were obtained at temperature 20 °C

The possibility of improving some properties of precast concrete tiles under static
load has been studied in this research. The experimental approach was adopted in this
research to investigate the effect of two types of wire mesh reinforcements on some
properties of precast concrete tiles especially flexural failure load. The experimental
program is divided into three groups with two ages of the test, the result of each age is an
average of three specimens; the first group consists of six specimens which refer to
reference tiles, the second group consists of eighteen specimens reinforced with different
shapes of a metal wire mesh. The third group consists of eighteen specimens reinforced
with different shapes of the plastic wire mesh. Three tests were conducted in this
research, flexural failure load, density, and absorption. The main conclusion from this
research is; the increasing in flexural failure load of specimens tiles according to reference
tiles was 10%, 17% and 25% for tiles reinforced with square plastic wire mesh, stripe
plastic wire mesh and specific plastic wire mesh, and 33%, 35% and 21% for square metal
wire mesh, stripe metal wire mesh, and specific metal wire mesh respectively

Impulsive noise is considered as one of the major source of disturbance in
the state-of-the-art multicarrier (MC) communication systems. Therefore, several
techniques are being constantly proposed to eliminate the effect of such noise. In
this work, a time domain matrix interleaved is compiled with a single carrier
frequency domain equalizer (SC-FDE) is proposed to reduce the deleterious effects
of impulsive noise. A mathematical model for the proposed scheme is also presented
in this paper. Simulation results show that the proposed technique superiors the
interleaved multicarrier system where the proposed scheme can completely avoid
the error floors not only at high signal-to-noise ratio (SNR) but also at heavily
distributed impulsive noise. The bit-error-rate (BER) of the alternative proposed
scheme decreases as the signal-to-noise ratio (SNR) increases whereas the BER of
the standard system suffers from error-floors with a constant BER at about 10-3
for
about 8 dB SNR for medium and heavily impulsive noise.

Despite the widespread use of hot mix asphalt (HMA) Overlay as one of the most
important methods of pavement maintenance, rehabilitation and development of roads, also
the ease and speed of implementation and low costs, there are many disadvantages and
problems that accompany the use, which is mostly due to reflection of the defects of layers
the old pavement on which the asphalt reinforcement layer is based. Therefore, this study
aims to prepare an asphalt mixture with a high performance and good specifications as
overlay layer, which can resist the problems and defects that are exposed to it and increase
its service life. Polypropylene granules of 19 mm particles size were used as an additive to
the asphalt binder (AC 60-70), with percentages 1, 2, 3, 4, 5 and 7% of the optimum asphalt
content weight. The volumetric and mechanical characteristics of mixture with this addition
were evaluated by using Marshall stability and indirect tensile testing (ITS). The study
showed that the use of 4% of the polypropylene granules of optimum asphalt weight gave
optimal performance compared to the unmodified mix. The optimum performance of the
asphalt concrete overlay during its design life, especially at high temperatures, was
improved by improving the physical and mechanical properties of the asphalt mixture and
by increasing its resistance to stresses is 32%.