Abstract: True stress-strain curve of railhead steel is required to
investigate the behaviour of railhead under wheel loading through elasto-plastic Finite Element (FE) analysis. To reduce the rate of wear, the railhead material is hardened through annealing and
quenching. The Australian standard rail sections are not fully hardened and hence suffer from non-uniform distribution of the
material property; usage of average properties in the FE modelling can potentially induce error in the predicted plastic strains. Coupons
obtained at varying depths of the railhead were, therefore, tested under axial tension and the strains were measured using strain gauges as well as an image analysis technique, known as the Particle Image Velocimetry (PIV). The head hardened steel exhibit existence of three distinct zones of yield strength; the yield strength as the ratio of the average yield strength provided in the standard (σyr=780MPa) and
the corresponding depth as the ratio of the head hardened zone along
the axis of symmetry are as follows: (1.17 σyr, 20%), (1.06 σyr, 20%-80%) and (0.71 σyr, > 80%). The stress-strain curves exhibit limited plastic zone with fracture occurring at strain less than 0.1.
Abstract: Lateral-torsional buckling (LTB) is one of the
phenomenae controlling the ultimate bending strength of steel Ibeams
carrying distributed loads on top flange. Built-up I-sections
are used as main beams and distributors. This study investigates the
ultimate bending strength of such beams with sections of different
classes including slender elements. The nominal strengths of the
selected beams are calculated for different unsupported lengths
according to the Provisions of the American Institute of Steel
Constructions (AISC-LRFD). These calculations are compared with
results of a nonlinear inelastic study using accurate FE model for this
type of loading. The goal is to investigate the performance of the
provisions for the selected sections. Continuous distributed load at
the top flange of the beams was applied at the FE model.
Imperfections of different values are implemented to the FE model to
examine their effect on the LTB of beams at failure, and hence, their
effect on the ultimate strength of beams. The study also introduces a
procedure for evaluating the performance of the provisions compared
with the accurate FEA results of the selected sections. A simplified
design procedure is given and recommendations for future code
updates are made.
Abstract: This study examined the toxicological effects and
safety of polypeptide k isolated from the seeds of Momordica
charantia in laboratory rats. 30 male Sprague Dawley rats (12 weeks
old, bodyweight 180-200 g) were randomly divided into 3 groups
(1000 mg/kg, 500 mg and 0 mg/kg). Rats were acclimatized to
laboratory conditions for 7 days and at day 8 rats were dosed orally
with polypeptide k (in 2% DMSO/normal saline) and the controls
received the dosed vehicle only. Rats were then observed for 72
hours before sacrificed. Rats were anaesthetized by pentobarbital
(50 mg/kg ip) and 2-3.0 mL of blood was taken by cardiac puncture
and rats were scarified by anaesthetic overdose. Immediately, organs
(heart, lungs, liver, kidneys) were weigh and taken for histology.
Organ sections were then evaluated by a histopathologist. Serum
samples were assayed for liver functions (ALT and γ-GT) and kidney
functions (BUN and creatinine). All rats showed normal behavior
after the dosing and no statistical changes were observed in all blood
parameters and organ weight. Histological examinations revealed
normal organ structures. In conclusion, dosing of rats up to 1000
mg/kg did not have any effects on the rat behavior, liver or kidney
functions nor histology of the selected organs.
Abstract: This paper presents a novel approach for the design of
microwave circuits using Adaptive Network Fuzzy Inference
Optimizer (ANFIO). The method takes advantage of direct synthesis
of subsections of the amplifier using very fast and accurate ANFIO
models based on exact simulations using ADS. A mapping from
course space to fine space known as space mapping is also used. The
proposed synthesis approach takes into account the noise and
scattering parameters due to parasitic elements to achieve optimal
results. The overall ANFIO system is capable of designing different
LNAs at different noise and scattering criteria. This approach offers
significantly reduced time in the design of microwave amplifiers
within the validity range of the ANFIO system. The method has been
proven to work efficiently for a 2.4GHz LNA example. The S21 of
10.1 dB and noise figure (NF) of 2.7 dB achieved for ANFIO while
S21 of 9.05 dB and NF of 2.6 dB achieved for ANN.
Abstract: In this study, a novel approach of image embedding is introduced. The proposed method consists of three main steps. First, the edge of the image is detected using Sobel mask filters. Second, the least significant bit LSB of each pixel is used. Finally, a gray level connectivity is applied using a fuzzy approach and the ASCII code is used for information hiding. The prior bit of the LSB represents the edged image after gray level connectivity, and the remaining six bits represent the original image with very little difference in contrast. The proposed method embeds three images in one image and includes, as a special case of data embedding, information hiding, identifying and authenticating text embedded within the digital images. Image embedding method is considered to be one of the good compression methods, in terms of reserving memory space. Moreover, information hiding within digital image can be used for security information transfer. The creation and extraction of three embedded images, and hiding text information is discussed and illustrated, in the following sections.
Abstract: Inflammatory bowel disease (IBD) is a chronic
relapsing-remitting condition that afflicts millions of people
throughout the world and impairs their daily functions and quality of
life. Treatment of IBD depends largely on 5-aminosalicylic acid (5-
ASA) and corticosteroids. The present study aimed to clarify the
effects of 5-aminosalicylic acid, budesonide and currcumin on 90
male albino rats against trinitrobenzene sulfonic acid (TNB) induced
colitis. TNB was injected intrarectally to 50 rats. The other 40 rats
served as control groups. Both 5-ASA (in a dose of 120 mg/kg) and
budesonide (in a dose of 0.1 mg/kg) were administered daily for one
week whereas currcumin was injected intraperitonially (in a dose of
30 mg/kg daily) for 14 days after injection of either TNB in the
colitis rats (group B) or saline in control groups (group A). The study
included estimation of macroscopic score index, histological
examination of H&E stained sections of the colonic tissue,
biochemical estimation of myeloperoxidase (MPO), nitric oxide
(NO), and caspase-3 levels, in addition to studying the effect of tested
drugs on colonic motility. It was found that budesonide and curcumin
improved mucosal healing, reduced both NO production and caspase-
3 level. They had the best impact on the disturbed colonic motility in
TNBS-model of colitis.
Abstract: In the context of large volume Big Divisor (nearly)
SLagy D3/D7 μ-Split SUSY [1], after an explicit identification
of first generation of SM leptons and quarks with fermionic superpartners
of four Wilson line moduli, we discuss the identification of
gravitino as a potential dark matter candidate by explicitly calculating
the decay life times of gravitino (LSP) to be greater than age of
universe and lifetimes of decays of the co-NLSPs (the first generation
squark/slepton and a neutralino) to the LSP (the gravitino) to be
very small to respect BBN constraints. Interested in non-thermal
production mechanism of gravitino, we evaluate the relic abundance
of gravitino LSP in terms of that of the co-NLSP-s by evaluating
their (co-)annihilation cross sections and hence show that the former
satisfies the requirement for a potential Dark Matter candidate. We
also show that it is possible to obtain a 125 GeV light Higgs in our
setup.
Abstract: In this paper, based on the past project cost and time
performance, a model for forecasting project cost performance is
developed. This study presents a probabilistic project control concept
to assure an acceptable forecast of project cost performance. In this
concept project activities are classified into sub-groups entitled
control accounts. Then obtain the Stochastic S-Curve (SS-Curve), for
each sub-group and the project SS-Curve is obtained by summing
sub-groups- SS-Curves. In this model, project cost uncertainties are
considered through Beta distribution functions of the project
activities costs required to complete the project at every selected time
sections through project accomplishment, which are extracted from a
variety of sources. Based on this model, after a percentage of the
project progress, the project performance is measured via Earned
Value Management to adjust the primary cost probability distribution
functions. Then, accordingly the future project cost performance is
predicted by using the Monte-Carlo simulation method.
Abstract: In this paper, the absorption and fluorescence
emission spectra of Yb:Y3Al5O12 (YAG)(25 at%) crystal as a disk
laser medium are measured at high temperature (300-450K). The
absorption and emission cross sections of Yb:YAG crystal are
determined using Reciprocity method. Temperature dependence of
941nm absorption cross section and 1031nm emission cross section
is extracted in the range of 300-450K. According to our experimental
results, an exponential temperature dependence between 300K and
450K is acquired for the 1031nm peak emission cross section and
also for 941nm peak absorption cross section of Yb:YAG crystal.
These results could be used for simulation and design of high power
highly doped Yb:YAG thin disk lasers.
Abstract: One of the efficient factors in comprehensive
development of an area is to provide water sources and on the other
hand the appropriate management of them. Population growth and
nourishment security for such a population necessitate the
achievement of constant development besides the reforming of
traditional management in order to increase the profit of sources; In
this case, the constant exploitation of sources for the next generations
will be considered in this program. The achievement of this
development without the consideration and possibility of water
development will be too difficult. Zayanderood basin with 41500
areas in square kilometers contains 7 sub-basins and 20 units of
hydrologic. In this basin area, from the entire environment
descending, just a small part will enter into the river currents and the
rest will be out of efficient usage by various ways. The most
important surface current of this basin is Zayanderood River with
403 kilometers length which is originated from east slopes of Zagros
mount and after draining of this basin area it will enter into
Gaavkhooni pond. The existence of various sources and
consumptions of water in Zayanderood basin, water transfer of the
other basin areas into this basin, of course the contradiction between
the upper and lower beneficiaries, the existence of worthwhile
natural ecosystems such as Gaavkhooni swamp in this basin area and
finally, the drought condition and lack of water in this area all
necessitate the existence of comprehensive management of water
sources in this central basin area of Iran as this method is a kind of
management which considers the development and the management
of water sources as an equilibrant way to increase the economical
and social benefits. In this study, it is tried to survey the network of
surface water sources of basin in upper and lower sections; at the
most, according to the difficulties and deficiencies of an efficient
management of water sources in this basin area, besides the
difficulties of water draining and the destructive phenomenon of
flood-water, the appropriate guidelines according to the region
conditions are presented in order to prevent the deviation of water in
upper sections and development of regions in lower sections of
Zayanderood dam.
Abstract: Whit the increasing of traffic, noise emanated from
motor vehicles increases as well, which subsequently causes adding
to the stress of modern city. Thus, it is needed to look for most
critical areas in terms of environmental and social impact of noise.
There are several critical situations for noise emanated from motor
vehicles such as stop and go situation which usually occurs near
junctions or at-grade intersections. This study was conducted in two
locations, most common types of intersections, crossroads and Tjunctions.
The highest average noise levels are recorded during Go
phase for T-junction, 64.4 dB, and Drive phase for crossroad, 64 dB.
It implies that the existence of intersection caused the noise level to
increase. The vehicles starting to move produce more sound than
when they travel at a constant speed along the intersection. It is
suggested that special considerations and priority of allocating funds
should be given to these critical spots.
Abstract: When the crisscross baffles and logarithmic spiral
baffles are placed on the bottom of the stirred tank with elliptic
bottom, using CFD software FLUENT simulates the velocity field of
the stirred tank with elliptic bottom and bottom baffles. Compare the
velocity field of stirred tank with bottom crisscross baffle to the
velocity field of stirred tank without bottom baffle and analysis the
flow pattern on the same axis-section and different cross-sections. The
sizes of the axial and radial velocity are compared respectively when
the stirred tank with bottom crisscross baffles, bottom logarithmic
spiral baffles and without bottom baffle. At the same time, the
numerical calculations of mixing power are compared when the stirred
tank with bottom crisscross baffles and bottom logarithmic spiral
baffles. Research shows that bottom crisscross baffles and logarithmic
spiral baffles have a great impact on flow pattern within the reactor
and improve the mixing effect better than without baffle. It also has
shown that bottom logarithmic spiral baffles has lower power
consumption than bottom crisscross baffles.
Abstract: Swedish truck industry is investigating the possibility
for implementing the use of Compacted Graphite Iron (CGI) in their
heavy duty diesel engines. Compared to the alloyed gray iron used
today, CGI has superior mechanical properties but not as good
machinability. Another issue that needs to be addressed when
implementing CGI is the inhomogeneous microstructure when the
cast component has different section thicknesses, as in cylinder
blocks. Thinner sections results in finer pearlite, in the material, with
higher strength. Therefore an investigation on its influence on
machinability was needed. This paper focuses on the effect that
interlamellar distance in pearlite has on CGI machinability and
material physical properties. The effect of pearlite content and
nodularity is also examined. The results showed that interlamellar
distance in pearlite did not have as large effect on the material
physical properties or machinability as pearlite content. The paper
also shows the difficulties of obtaining a homogeneous
microstructure in inhomogeneous workpieces.
Abstract: Nowadays in applications of renewable energy sources
it is important to develop powerful and energy-saving photovoltaic
converters and to keep the prescriptions of the standards. In grid
connected PV converters the obvious solution to increase the
efficiency is to reduce the switching losses. Our new developed
control method reduces the switching losses and keeps the limitations
of the harmonic distortion standards. The base idea of the method is
the utilization of 3-state control causing discontinuous current mode
at low input power. In the following sections the control theory, the
realizations and the simulation results are presented.
Abstract: This paper presents an analytical model to estimate
the cost of an optimized design of reinforced concrete isolated
footing base on structural safety. Flexural and optimized formulas for
square and rectangular footingare derived base on ACI building code
of design, material cost and optimization. The optimization
constraints consist of upper and lower limits of depth and area of
steel. Footing depth and area of reinforcing steel are to be minimized
to yield the optimal footing dimensions. Optimized footing materials
cost of concrete, reinforcing steel and formwork of the designed
sections are computed. Total cost factor TCF and other cost factors
are developed to generalize and simplify the calculations of footing
material cost. Numerical examples are presented to illustrate the
model capability of estimating the material cost of the footing for a
desired axial load.
Abstract: This paper describes a new algorithm of arrangement
in parallel, based on Odd-Even Mergesort, called division and
concurrent mixes. The main idea of the algorithm is to achieve that
each processor uses a sequential algorithm for ordering a part of the
vector, and after that, for making the processors work in pairs in
order to mix two of these sections ordered in a greater one, also
ordered; after several iterations, the vector will be completely
ordered. The paper describes the implementation of the new
algorithm on a Message Passing environment (such as MPI). Besides,
it compares the obtained experimental results with the quicksort
sequential algorithm and with the parallel implementations (also on
MPI) of the algorithms quicksort and bitonic sort. The comparison
has been realized in an 8 processors cluster under GNU/Linux which
is running on a unique PC processor.
Abstract: This paper proposes a new version of the Particle
Swarm Optimization (PSO) namely, Modified PSO (MPSO) for
model order formulation of Single Input Single Output (SISO) linear
time invariant continuous systems. In the General PSO, the
movement of a particle is governed by three behaviors namely
inertia, cognitive and social. The cognitive behavior helps the
particle to remember its previous visited best position. In Modified
PSO technique split the cognitive behavior into two sections like
previous visited best position and also previous visited worst
position. This modification helps the particle to search the target very
effectively. MPSO approach is proposed to formulate the higher
order model. The method based on the minimization of error
between the transient responses of original higher order model and
the reduced order model pertaining to the unit step input. The results
obtained are compared with the earlier techniques utilized, to validate
its ease of computation. The proposed method is illustrated through
numerical example from literature.
Abstract: Decision support systems are usually based on
multidimensional structures which use the concept of hypercube.
Dimensions are the axes on which facts are analyzed and form a
space where a fact is located by a set of coordinates at the
intersections of members of dimensions. Conventional
multidimensional structures deal with discrete facts linked to discrete
dimensions. However, when dealing with natural continuous
phenomena the discrete representation is not adequate. There is a
need to integrate spatiotemporal continuity within multidimensional
structures to enable analysis and exploration of continuous field data.
Research issues that lead to the integration of spatiotemporal
continuity in multidimensional structures are numerous. In this paper,
we discuss research issues related to the integration of continuity in
multidimensional structures, present briefly a multidimensional
model for continuous field data. We also define new aggregation
operations. The model and the associated operations and measures
are validated by a prototype.
Abstract: Recently many research has been conducted to
retrieve pertinent parameters and adequate models for automatic
music genre classification. In this paper, two measures based upon
information theory concepts are investigated for mapping the features
space to decision space. A Gaussian Mixture Model (GMM) is used
as a baseline and reference system. Various strategies are proposed
for training and testing sessions with matched or mismatched
conditions, long training and long testing, long training and short
testing. For all experiments, the file sections used for testing are
never been used during training. With matched conditions all
examined measures yield the best and similar scores (almost 100%).
With mismatched conditions, the proposed measures yield better
scores than the GMM baseline system, especially for the short testing
case. It is also observed that the average discrimination information
measure is most appropriate for music category classifications and on
the other hand the divergence measure is more suitable for music
subcategory classifications.
Abstract: In this work, axisymetric CFD simulation of fixed bed
GTL reactor has been conducted, using computational fluid dynamics
(CFD). In fixed bed CFD modeling, when N (tube-to-particle
diameter ratio) has a large value, it is common to consider the packed
bed as a porous media. Synthesis gas (a mixture of predominantly
carbon monoxide and hydrogen) was fed to the reactor. The reactor
length was 20 cm, divided to three sections. The porous zone was in
the middle section of the reactor. The model equations were solved
employing finite volume method. The effects of particle diameter,
bed voidage, fluid velocity and bed length on pressure drop have
been investigated. Simulation results showed these parameters could
have remarkable impacts on the reactor pressure drop.