Abstract: Microstructural and electrical properties of
Cu-chromium alloy (Cu-Cr) dispersed with vapor-grown carbon fiber
(VGCF) prepared by powder metallurgy (P/M) process have been
investigated. Cu-0.7 mass% Cr pre-alloyed powder (Cu-Cr) made by
water atomization process was used as raw materials, which contained
solid solute Cr elements in Cu matrix. The alloy powder coated with
un-bundled VGCF by using oil coating process was consolidated at
1223 K in vacuum by spark plasma sintering, and then extruded at
1073 K. The extruded Cu-Cr alloy (monolithic alloy) had 209.3 MPa
YS and 80.4 IACS% conductivity. The extruded Cu-Cr with 0.1
mass% VGCF composites revealed a small decrease of YS compared
to the monolithic Cu-Cr alloy. On the other hand, the composite had a
higher electrical conductivity than that of the monolithic alloy. For
example, Cu-Cr with 0.1 mass% VGCF composite sintered for 5 h
showed 182.7 MPa YS and 89.7 IACS% conductivity. In the case of
Cu-Cr with VGCFs composites, the Cr concentration was observed
around VGCF by SEM-EDS analysis, where Cr23C6 compounds were
detected by TEM observation. The amount of Cr solid solution in the
matrix of the Cu-Cr composites alloy was about 50% compared to the
monolithic Cu-Cr sintered alloy, and resulted in the remarkable
increment of the electrical conductivity.
Abstract: Thousands of organisations store important and
confidential information related to them, their customers, and their
business partners in databases all across the world. The stored data
ranges from less sensitive (e.g. first name, last name, date of birth) to
more sensitive data (e.g. password, pin code, and credit card
information). Losing data, disclosing confidential information or
even changing the value of data are the severe damages that
Structured Query Language injection (SQLi) attack can cause on a
given database. It is a code injection technique where malicious SQL
statements are inserted into a given SQL database by simply using a
web browser. In this paper, we propose an effective pattern
recognition neural network model for detection and classification of
SQLi attacks. The proposed model is built from three main elements
of: a Uniform Resource Locator (URL) generator in order to generate
thousands of malicious and benign URLs, a URL classifier in order
to: 1) classify each generated URL to either a benign URL or a
malicious URL and 2) classify the malicious URLs into different
SQLi attack categories, and a NN model in order to: 1) detect either a
given URL is a malicious URL or a benign URL and 2) identify the
type of SQLi attack for each malicious URL. The model is first
trained and then evaluated by employing thousands of benign and
malicious URLs. The results of the experiments are presented in
order to demonstrate the effectiveness of the proposed approach.
Abstract: Transportation of long turbine blades from one place
to another is a difficult process. Hence a feasibility study of
modularization of wind turbine blade was taken from structural
standpoint through finite element analysis. Initially, a non-segmented
blade is modeled and its structural behavior is evaluated to serve as
reference. The resonant, static bending and fatigue tests are simulated
in accordance with IEC61400-23 standard for comparison purpose.
The non-segmented test blade is separated at suitable location based
on trade off studies and the segments are joined with an innovative
double strap bonded joint configuration. The adhesive joint is
modeled by adopting cohesive zone modeling approach in ANSYS.
The developed blade model is analyzed for its structural response
through simulation. Performances of both the blades are found to be
similar, which indicates that, efficient segmentation of the long blade
is possible which facilitates easy transportation of the blades and on
site reassembling. The location selected for segmentation and
adopted joint configuration has resulted in an efficient segmented
blade model which proves the methodology adopted for segmentation
was quite effective. The developed segmented blade appears to be the
viable alternative considering its structural response specifically in
fatigue within considered assumptions.
Abstract: Non-crimp 3D orthogonal fabric composite is one of
the textile-based composite materials that are rapidly developing
light-weight engineering materials. The present paper focuses on
geometric and micromechanical modeling of non-crimp 3D
orthogonal carbon fabric and composites reinforced with it for
aerospace applications. In this research meso-finite element (FE)
modeling employs for stress analysis in different load conditions.
Since mechanical testing of expensive textile carbon composites with
specific application isn't affordable, simulation composite in a virtual
environment is a helpful way to investigate its mechanical properties
in different conditions.
Abstract: To understand the friction stir welding process, it is
very important to know the nature of the material flow in and around
the tool. The process is a combination of both thermal as well as
mechanical work i.e. it is a coupled thermo-mechanical process.
Numerical simulations are very much essential in order to obtain a
complete knowledge of the process as well as the physics underlying
it. In the present work a model based approach is adopted in order to
study material flow. A thermo-mechanical based CFD model is
developed using a Finite Element package, Comsol Multiphysics.
The fluid flow analysis is done. The model simultaneously predicts
shear strain fields, shear strain rates and shear stress over the entire
workpiece for the given conditions. The flow fields generated by the
streamline plot give an idea of the material flow. The variation of
dynamic viscosity, velocity field and shear strain fields with various
welding parameters is studied. Finally the result obtained from the
above mentioned conditions is discussed elaborately and concluded.
Abstract: The polymer foil used for manufacturing of
laminated glass members behaves in a viscoelastic manner with
temperature dependance. This contribution aims at incorporating
the time/temperature-dependent behavior of interlayer to our earlier
elastic finite element model for laminated glass beams. The model
is based on a refined beam theory: each layer behaves according
to the finite-strain shear deformable formulation by Reissner and
the adjacent layers are connected via the Lagrange multipliers
ensuring the inter-layer compatibility of a laminated unit. The
time/temperature-dependent behavior of the interlayer is accounted
for by the generalized Maxwell model and by the time-temperature
superposition principle due to the Williams, Landel, and Ferry.
The resulting system is solved by the Newton method with
consistent linearization and the viscoelastic response is determined
incrementally by the exponential algorithm. By comparing the model
predictions against available experimental data, we demonstrate that
the proposed formulation is reliable and accurately reproduces the
behavior of the laminated glass units.
Abstract: Channel sections are widely used in practice as beams.
However, design rules for eccentrically loaded (not through shear
center) beams with channel cross- sections are not available in
Eurocode 3. This paper compares the ultimate loads based on the
adjusted design rules for lateral torsional buckling of eccentrically
loaded channel beams in bending to the ultimate loads obtained with
Finite Element (FE) simulations on the basis of a parameter study.
Based on the proposed design rule, this study has led to a new design
rule which conforms to Eurocode 3.
Abstract: The article presents a plasma chemical technology for
processing solid fuels, using examples of bituminous and brown
coals. Thermodynamic and experimental investigation of the
technology was made. The technology allows producing synthesis
gas from the coal organic mass and valuable components (technical
silicon, ferrosilicon, aluminum, and carbon silicon, as well as
microelements of rare metals, such as uranium, molybdenum,
vanadium, etc.) from the mineral mass. The thusly produced highcalorific
synthesis gas can be used for synthesis of methanol, as a
high-calorific reducing gas instead of blast-furnace coke as well as
power gas for thermal power plants.
Abstract: A simple adaptive voice activity detector (VAD) is
implemented using Gabor and gammatone atomic decomposition of
speech for high Gaussian noise environments. Matching pursuit is
used for atomic decomposition, and is shown to achieve optimal
speech detection capability at high data compression rates for low
signal to noise ratios. The most active dictionary elements found by
matching pursuit are used for the signal reconstruction so that the
algorithm adapts to the individual speakers dominant time-frequency
characteristics. Speech has a high peak to average ratio enabling
matching pursuit greedy heuristic of highest inner products to isolate
high energy speech components in high noise environments. Gabor
and gammatone atoms are both investigated with identical
logarithmically spaced center frequencies, and similar bandwidths.
The algorithm performs equally well for both Gabor and gammatone
atoms with no significant statistical differences. The algorithm
achieves 70% accuracy at a 0 dB SNR, 90% accuracy at a 5 dB SNR
and 98% accuracy at a 20dB SNR using 30d B SNR as a reference
for voice activity.
Abstract: Fruit juices play important roles in human health as
being a key part of nutrition. Juice and nectar are two categories of
drinks with so many variations for consumers, regardless of age,
lifestyle and taste preferences, which they can find their favorites.
Juices contain 100% pulp when pulp content of ‘nectar’ changes
between 25%-50%. In this study, potassium (K), magnesium (Mg),
and phosphorus (P) contents in orange juice and nectar is determined
for conscious consumption. For this purpose inductively coupled
plasma optical emission spectrometry (ICP-OES) is used to find out
potassium (K), magnesium (Mg), and phosphorus (P) contents in
orange juices and nectar. Furthermore, the daily intake of elements
from orange juice and nectar that affects human health is also
investigated. From the results of experiments K, Mg and P contents
are found in orange juice as 1351; 73,25; 89,27 ppm and in orange
nectar as 986; 33,76; 51,30 respectively.
Abstract: Mangosteen (Garcinia mangostana) pericarp is
considered as agricultural waste and not fully utilized in food
products. It is widely reported that mangosteen pericarp contains high
antioxidant properties. The objective of this study is to develop novel
yellow alkaline noodle (YAN) substituted with different levels of
mangosteen pericarp powder (MPP). YAN formulation was
substituted with different levels of MPP (0%, 5%, 10% and 15%).
The effect on nutritional and antioxidant properties was evaluated.
Higher substitution levels of MPP resulted in significant increase
(p
Abstract: One of the main challenges in using the Discrete
Element Method (DEM) is to specify the correct input parameter
values. In general, the models are sensitive to the input parameter
values and accurate results can only be achieved if the correct values
are specified. For the linear contact model, micro-parameters such as
the particle density, stiffness, coefficient of friction, as well as the
particle size and shape distributions are required. There is a need for
a procedure to accurately calibrate these parameters before any
attempt can be made to accurately model a complete bulk materials
handling system. Since DEM is often used to model applications in
the mining and quarrying industries, a calibration procedure was
developed for materials that consist of relatively large (up to 40 mm
in size) particles. A coarse crushed aggregate was used as the test
material. Using a specially designed large shear box with a diameter
of 590 mm, the confined Young’s modulus (bulk stiffness) and
internal friction angle of the material were measured by means of the
confined compression test and the direct shear test respectively. DEM
models of the experimental setup were developed and the input
parameter values were varied iteratively until a close correlation
between the experimental and numerical results was achieved. The
calibration process was validated by modelling the pull-out of an
anchor from a bed of material. The model results compared well with
experimental measurement.
Abstract: In this paper, an analytical simplified method for
calculating elasto-plastic stresses strains of notched bodies subject to
non-proportional loading paths is discussed. The method was based
on the Neuber notch correction, which relates the incremental elastic
and elastic-plastic strain energy densities at the notch root and the
material constitutive relationship. The validity of the method was
presented by comparing computed results of the proposed model
against finite element numerical data of notched shaft. The
comparison showed that the model estimated notch-root elasto-plastic
stresses strains with good accuracy using linear-elastic stresses. The
prosed model provides more efficient and simple analysis method
preferable to expensive experimental component tests and more
complex and time consuming incremental non-linear FE analysis.
The model is particularly suitable to perform fatigue life and fatigue
damage estimates of notched components subjected to nonproportional
loading paths.
Abstract: The present study was carried out to investigate the
effect of alloying elements and thermo-mechanical treatment (TMT)
i.e. hot rolling and forging with different reduction ratios on the
hardness (HV) and impact toughness (J) of heat-treated low alloy
steels. An understanding of the combined effect of TMT and alloying
elements and by measuring hardness, impact toughness, resulting
from different heat treatment following TMT of the low alloy steels,
it is possible to determine which conditions yielded optimum
mechanical properties and high strength to weight ratio.
Experimental Correlations between hot work reduction ratio,
hardness and impact toughness for thermo-mechanically heat treated
low alloy steels are analyzed quantitatively, and both regression and
mathematical hardness and impact toughness models are developed.
Abstract: The model tests were conducted in the laboratory
without and with Plastic recycled polymer in fly ash steep slopes
overlaying soft foundation soils like fly ash and powai soil in order to
check the stability of steep slope. In this experiment, fly ash is used
as a filling material and Plastic Recycled Polymers of diameter =
3mm and length = 4mm were made from waste plastic product (lower
grade plastic product). The properties of fly ash and Plastic recycled
polymers are determined. From the experiments, load and settlement
have measured. From these data, load –settlement curves have
reported. It has been observed from test results that load carrying
capacity of mixture fly ash with Plastic Recycled Polymers slope is
more than that of fly ash slope. The deformation of Plastic Recycled
Polymers slope is slightly more than that of fly ash slope. A Finite
Element Method (F.E.M.) was also evaluated using PLAXIS 3D
version. The failure pattern, deformations and factor of safety are
reported based on analytical programme. The results from
experimental data and analytical programme are compared and
reported.
Abstract: A central element of higher education today is the
“core” or “general education” curriculum: that configuration of
courses that often encompasses the essence of liberal arts education.
Ensuring that such offerings reflect the mission and values of the
institution is a challenge faced by most college and universities, often
more than once. This paper presents an action model of program
planning designed to structure the processes of developing,
implementing and revising core curricula in a manner consistent with
key institutional goals and objectives. Through presentation of a case
study from a university in the United States, the elements of needs
assessment, stakeholder investment and collaborative compromise
are shown as key components of a planning strategy that can produce
a general education program that is comprehensive, academically
rigorous, assessable, and mission consistent. The paper concludes
with recommendations for both the implementation and evaluation of
such programs in practice.
Abstract: This paper is part of a study to develop robots for
farming. As such power requirement to operate equipment attach to
such robots become an important factor. Soil-tool interaction plays
major role in power consumption, thus predicting accurately the
forces which act on the blade during the farming is very important for
optimal designing of farm equipment. In this paper, a finite element
investigation for tillage tools and soil interaction is described by
using an inelastic constitutive material law for agriculture
application. A 3-dimensional (3D) nonlinear finite element analysis
(FEA) is developed to examine behavior of a blade with different
rake angles moving in a block of soil, and to estimate the blade force.
The soil model considered is an elastic-plastic with non-associated
Drucker-Prager material model. Special use of contact elements are
employed to consider connection between soil-blade and soil-soil
surfaces. The FEA results are compared with experimental ones,
which show good agreement in accurately predicting draft forces
developed on the blade when it moves through the soil. Also a very
good correlation was obtained between FEA results and analytical
results from classical soil mechanics theories for straight blades.
These comparisons verified the FEA model developed. For analyzing
complicated soil-tool interactions and for optimum design of blades,
this method will be useful.
Abstract: Transmission shafts are affected by various forces, for
example, during acceleration or sudden breaks, bending during
transportation, vertical forces that lead to cuts. One of the main
failures in combines is breaking shaft which repairmen refer it.
Structural resistance of canal against torque is very important in the
beginning of the movement. For analyzing stress, a typical sample
from a type of combine was selected, called JD955 combine. Long
shaft in this combine was analyzed with finite element method by
Ansys13 generic package under static load. Conducted analysis
showed that there is a maximum stress in contact surfaces of
indentations and also in place of changing diameter. Safety factor
value is low in parts of the shaft and this increases the probability of
failure at these points. To improve the conditions with the least cost
and an approach of product improvement, using alternative alloy is
important.
Abstract: Coal is an important non-renewable energy source of
and can be associated with radioactive elements. In Figueira city,
Paraná state, Brazil, it was recorded high uranium activity near the
coal mine that supplies a local thermoelectric power plant. In this
context, the radon activity (Rn-222, produced by the Ra-226 decay in
the U-238 natural series) was evaluated in groundwater, river water
and effluents produced from the acid mine drainage in the coal reject
dumps. The samples were collected in August 2013 and in February
2014 and analyzed at LABIDRO (Laboratory of Isotope and
Hydrochemistry), UNESP, Rio Claro city, Brazil, using an alpha
spectrometer (AlphaGuard) adjusted to evaluate the mean radon
activity concentration in five cycles of 10 minutes. No radon activity
concentration above 100 Bq.L-1, which was a previous critic value
established by the World Health Organization. The average radon
activity concentration in groundwater was higher than in surface
water and in effluent samples, possibly due to the accumulation of
uranium and radium in the aquifer layers that favors the radon
trapping. The lower value in the river waters can indicate dilution and
the intermediate value in the effluents may indicate radon absorption
in the coal particles of the reject dumps. The results also indicate that
the radon activities in the effluents increase with the sample
acidification, possibly due to the higher radium leaching and the
subsequent radon transport to the drainage flow. The water samples
of Laranjinha River and Ribeirão das Pedras stream, which,
respectively, supply Figueira city and receive the mining effluent,
exhibited higher pH values upstream the mine, reflecting the acid
mine drainage discharge. The radionuclides transport indicates the
importance of monitoring their activity concentration in natural
waters due to the risks that the radioactivity can represent to human
health.
Abstract: The efficiency of the actuation system of exoskeletons
and active orthoses for lower limbs is a significant aspect of the
design of such devices because it affects their efficacy. The F-IVT is
an innovative actuation system to power artificial knee joint with
energy recovery capabilities. Its key and non-conventional elements
are a flywheel that acts as a mechanical energy storage system, and
an Infinitely Variable Transmission (IVT). The design of the F-IVT
can be optimized for a certain walking condition, resulting in a heavy
reduction of both the electric energy consumption and of the electric
peak power. In this work, by means of simulations of level ground
walking at different speeds, it is demonstrated that the F-IVT is still
an advantageous actuator which permits to save energy consumption
and to downsize the electric motor even when it does not work in
nominal conditions.