Abstract: In this investigation, we have evaluated the effects of
arsenic trioxide on hepatic function in pregnant and lactating Swiss
albino mice and their suckling pups. Experiments were carried out on
female mice given 175 ppm As2O3 in their drinking water from the
14th day of pregnancy until day 14 after delivery. Our results showed
a significant decrease in plasma levels of total protein and albumin,
cholesterol and triglyceride in As2O3 treated mice and their pups. The
hyperbilirubinemia and the increased plasma total alkaline
phosphatase activity suggested the presence of cholestasis.
Transaminase activities as well as lactate deshydrogenase activity in
plasma, known as biomarkers of hepatocellular injury, were elevated
indicating hepatic cells’ damage after treatment with As2O3.
Exposure to arsenic led to an increase of liver thiobarbituric acid
reactive substances level along with a concomitant decrease in the
activities of superoxide dismutase, catalase and glutathione
peroxidase and in glutathione.
Abstract: Near-infrared spectroscopy (NIRS) has been widely
used as a non-invasive method to measure brain activity, but it is
corrupted by baseline drift noise. Here we present a method to measure
regional cerebral blood flow as a derivative of NIRS output. We
investigate whether, when listening to languages, blood flow can
reasonably localize and represent regional brain activity or not. The
prefrontal blood flow distribution pattern when advanced
second-language listeners listened to a second language (L2) was most
similar to that when listening to their first language (L1) among the
patterns of mean and standard deviation. In experiments with 25
healthy subjects, the maximum blood flow was localized to the left
BA46 of advanced listeners. The blood flow presented is robust to
baseline drift and stably localizes regional brain activity.
Abstract: The aim of this paper is to perform experimental
modal analysis (EMA) of reinforced concrete (RC) square slabs.
EMA is the process of determining the modal parameters (Natural
Frequencies, damping factors, modal vectors) of a structure from a
set of frequency response functions FRFs (curve fitting). Although,
experimental modal analysis (or modal testing) has grown steadily in
popularity since the advent of the digital FFT spectrum analyzer in
the early 1970’s, studying all types of members and materials using
such method have not yet been well documented. Therefore, in this
work, experimental tests were conducted on RC square slab
specimens of dimensions 600mm x 600mmx 40mm. Experimental
analysis was based on freely supported boundary condition.
Moreover, impact testing as a fast and economical means of finding
the modes of vibration of a structure was used during the
experiments. In addition, Pico Scope 6 device and MATLAB
software were used to acquire data, analyze and plot Frequency
Response Function (FRF). The experimental natural frequencies
which were extracted from measurements exhibit good agreement
with analytical predictions. It is showed that EMA method can be
usefully employed to investigate the dynamic behavior of RC slabs.
Abstract: Elastomeric dielectric material has recently become a
new alternative for actuator technology. The characteristics of
dielectric elastomers placed between two electrodes to withstand
large strain when electrodes are charged has attracted the attention of
many researcher to study this material for actuator technology. Thus,
in the past few years Danfoss Ventures A/S has established their own
dielectric electro-active polymer (DEAP), which was called
PolyPower.
The main objective of this work was to investigate the dynamic
characteristics for vibration control of a PolyPower actuator folded in
‘pull’ configuration. A range of experiments was carried out on the
folded actuator including passive (without electrical load) and active
(with electrical load) testing. For both categories static and dynamic
testing have been done to determine the behavior of folded DEAP
actuator.
Voltage-Strain experiments show that the DEAP folded actuator is
a non-linear system. It is also shown that the voltage supplied has no
effect on the natural frequency. Finally, varying AC voltage with
different amplitude and frequency shows the parameters that
influence the performance of DEAP folded actuator. As a result, the
actuator performance dominated by the frequency dependence of the
elastic response and was less influenced by dielectric properties.
Abstract: Thin ZnO films are deposited on glass substrates via
sol–gel method and dip-coating. The films are prepared from zinc
acetate dehydrate as a starting reagent. After that the as-prepared
ZnO sol is aged for different periods (0, 1, 3, 5, 10, 15 and 30 days).
Nanocrystalline thin films are deposited from various sols. The
effect ZnO sols aging time on the structural and photocatalytic
properties of the films is studied. The films surface is studied by
Scanning Electron Microscopy. The effect of the aging time of the
starting solution is studied in the photocatalytic degradation of
Reactive Black 5 (RB5) by UV-vis spectroscopy. The experiments
are conducted upon UV-light illumination and in complete darkness.
The variation of the absorption spectra shows the degradation of RB5
dissolved in water, as a result of the reaction, occurring on the surface
of the films and promoted by UV irradiation. The initial
concentrations of dye (5, 10 and 20 ppm) and the effect of the aging
time are varied during the experiments. The results show, that the
increasing aging time of starting solution with respect to ZnO
generally promotes photocatalytic activity. The thin films obtained
from ZnO sol, which is aged 30 days have best photocatalytic
degradation of the dye (97,22%) in comparison with the freshly
prepared ones (65,92%). The samples and photocatalytic
experimental results are reproducible. Nevertheless, all films exhibit
a substantial activity in both UV light and darkness, which is
promising for the development of new ZnO photocatalysts by sol-gel
method.
Abstract: The present study was undertaken to investigate the
effect of aging parameters (time and temperature) on the mechanical
properties of Be-and/or Zr- treated Al-Mg-Zn (7075) alloys. Ultimate
tensile strength, 0.5% offset yield strength and % elongation
measurements were carried out on specimens prepared from cast and
heat treated 7075 alloys containing Be and/or Zr. Different aging
treatment were carried out for the as solution treated (SHT)
specimens (after quenching in warm water). The specimens were
aged at different conditions; Natural and artificial aging was carried
out at room temperature, 120C, 150C, 180C and 220C for different
periods of time. Duplex aging was performed for SHT conditions
(pre-aged at different time and temperature followed by high
temperature aging). Ultimate tensile strength, yield strength and %
elongation data results as a function of different aging parameters are
analysed. A statistical design of experiments (DOE) approach using
fractional factorial design is applied to acquire an understanding of
the effects of these variables and their interactions on the mechanical
properties of Be- and/or Zr- treated 7075 alloys. Mathematical
models are developed to relate the alloy mechanical properties with
the different aging parameters.
Abstract: Speech enhancement is a long standing problem with
numerous applications like teleconferencing, VoIP, hearing aids and
speech recognition. The motivation behind this research work is to
obtain a clean speech signal of higher quality by applying the optimal
noise cancellation technique. Real-time adaptive filtering algorithms
seem to be the best candidate among all categories of the speech
enhancement methods. In this paper, we propose a speech
enhancement method based on Recursive Least Squares (RLS)
adaptive filter of speech signals. Experiments were performed on
noisy data which was prepared by adding AWGN, Babble and Pink
noise to clean speech samples at -5dB, 0dB, 5dB and 10dB SNR
levels. We then compare the noise cancellation performance of
proposed RLS algorithm with existing NLMS algorithm in terms of
Mean Squared Error (MSE), Signal to Noise ratio (SNR) and SNR
Loss. Based on the performance evaluation, the proposed RLS
algorithm was found to be a better optimal noise cancellation
technique for speech signals.
Abstract: Different tools and technologies were implemented
for Crisis Response and Management (CRM) which is generally
using available network infrastructure for information exchange.
Depending on type of disaster or crisis, network infrastructure could
be affected and it could not be able to provide reliable connectivity.
Thus any tool or technology that depends on the connectivity could
not be able to fulfill its functionalities. As a solution, a new message
exchange framework has been developed. Framework provides
offline/online information exchange platform for CRM Information
Systems (CRMIS) and it uses XML compression and packet
prioritization algorithms and is based on open source web
technologies. By introducing offline capabilities to the web
technologies, framework will be able to perform message exchange
on unreliable networks. The experiments done on the simulation
environment provide promising results on low bandwidth networks
(56kbps and 28.8 kbps) with up to 50% packet loss and the solution is
to successfully transfer all the information on these low quality
networks where the traditional 2 and 3 tier applications failed.
Abstract: This paper presents the details of a numerical study of
buckling and post buckling behaviour of laminated carbon fiber
reinforced plastic (CFRP) thin-walled cylindrical shell under axial
compression using asymmetric meshing technique (AMT) by
ABAQUS. AMT is considered to be a new perturbation method to
introduce disturbance without changing geometry, boundary
conditions or loading conditions. Asymmetric meshing affects both
predicted buckling load and buckling mode shapes. Cylindrical shell
having lay-up orientation [0^o/+45^o/-45^o/0^o] with radius to thickness
ratio (R/t) equal to 265 and length to radius ratio (L/R) equal to 1.5 is
analysed numerically. A series of numerical simulations
(experiments) are carried out with symmetric and asymmetric
meshing to study the effect of asymmetric meshing on predicted
buckling behaviour. Asymmetric meshing technique is employed in
both axial direction and circumferential direction separately using
two different methods, first by changing the shell element size and
varying the total number elements, and second by varying the shell
element size and keeping total number of elements constant. The
results of linear analysis (Eigenvalue analysis) and non-linear
analysis (Riks analysis) using symmetric meshing agree well with
analytical results. The results of numerical analysis are presented in
form of non-dimensional load factor, which is the ratio of buckling
load using asymmetric meshing technique to buckling load using
symmetric meshing technique. Using AMT, load factor has about 2%
variation for linear eigenvalue analysis and about 2% variation for
non-linear Riks analysis. The behaviour of load end-shortening curve
for pre-buckling is same for both symmetric and asymmetric meshing
but for asymmetric meshing curve behaviour in post-buckling
becomes extraordinarily complex. The major conclusions are:
different methods of AMT have small influence on predicted
buckling load and significant influence on load displacement curve
behaviour in post buckling; AMT in axial direction and AMT in
circumferential direction have different influence on buckling load
and load displacement curve in post-buckling.
Abstract: Vancron 40, a nitrided powder metallurgical tool
Steel, is used in cold work applications where the predominant failure
mechanisms are adhesive wear or galling. Typical applications of
Vancron 40 are among others fine blanking, cold extrusion, deep
drawing and cold work rolls for cluster mills. Vancron 40 positive
results for cold work rolls for cluster mills and as a tool for some
severe metal forming process makes it competitive compared to other
type of work rolls that require higher precision, among others in cold
rolling of thin stainless steel, which required high surface finish
quality. In this project, three roll materials for cold rolling of stainless
steel strip was examined, Vancron 40, Narva 12B (a high-carbon,
high-chromium tool steel alloyed with tungsten) and Supra 3 (a
Chromium-molybdenum tungsten-vanadium alloyed high speed
steel). The purpose of this project was to study the depth profiles of
the ironed stainless steel strips, emergence of galling and to study the
lubrication performance used by steel industries. Laboratory
experiments were conducted to examine scratch of the strip, galling
and surface roughness of the roll materials under severe tribological
conditions. The critical sliding length for onset of galling was
estimated for stainless steel with four different lubricants. Laboratory
experiments result of performance evaluation of resistance capability
of rolls toward adhesive wear under severe conditions for low and
high reductions. Vancron 40 in combination with cold rolling
lubricant gave good surface quality, prevents galling of
metal surfaces and good bearing capacity.
Abstract: Solenoid operated electromagnetic control valve
(ECV) playing an important role for car’s air conditioning control
system. ECV is used in external variable displacement swash plate
type compressor and controls the entire air conditioning system by
means of a pulse width modulation (PWM) input signal supplying
from an external source (controller). Complete form of ECV contains
number of internal features like valve body, core, valve guide,
plunger, guide pin, plunger spring, bellows etc. While designing the
ECV; dimensions of different internal items must meet the standard
requirements as it is quite challenging. In this research paper,
especially the dimensioning of ECV body and its three pressure ports
through which the air/refrigerant passes are considered. Here internal
leakage test analysis of ECV body is being carried out from its
discharge port (Pd) to crankcase port (Pc) when the guide valve is
placed inside it. The experiments have made both in ordinary and
digital system using different assumptions and thereafter compare the
results.
Abstract: Composite materials, due to their unique properties
such as high strength to weight ratio, corrosion resistance, and impact
resistance have huge potential as structural materials in automotive,
construction and transportation applications. However, these
properties often come at higher cost owing to complex design
methods, difficult manufacturing processes and raw material cost.
Traditionally, tapered laminated composite structures are
manufactured using autoclave manufacturing process by ply drop off
technique. Autoclave manufacturing though very powerful suffers
from high capital investment and higher energy consumption. As per
the current trends in composite manufacturing, Out of Autoclave
(OoA) processes are looked as emerging technologies for
manufacturing the structural composite components for aerospace
and defense applications. However, there is a need for improvement
among these processes to make them reliable and consistent. In this
paper, feasibility of using out of autoclave process to manufacture the
variable thickness cantilever beam is discussed. The minimum weight
design for the composite beam is obtained using constant stress beam
concept by tailoring the thickness of the beam. Ply drop off
techniques was used to fabricate the variable thickness beam from
glass/epoxy prepregs. Experiments were conducted to measure
bending stresses along the span of the cantilever beam at different
intervals by applying the concentrated load at the free end.
Experimental results showed that the stresses in the bean at different
intervals were constant. This proves the ability of OoA process to
manufacture the constant stress beam. Finite element model for the
constant stress beam was developed using commercial finite element
simulation software. It was observed that the simulation results
agreed very well with the experimental results and thus validated
design and manufacturing approach used.
Abstract: Fugitive particulate matter (PM) is a major source of
airborne pollution in the Middle East countries. The meteorological
conditions and topography of the area makes it highly susceptible to
wind-blown particles which raise many air quality concerns. Air
quality tools such as field monitoring, emission factors and dispersion
modeling have been used in previous research studies to analyze the
release and impacts of fugitive PM in the region. However, these
tools have been originally developed based on experiments made for
European and North American regions. In this work, an experimental
campaign was conducted on April-May 2014 in a construction site in
Doha city, Qatar. The ultimate goal is to evaluate the applicability of
the existing emission factors for construction sites in dry and arid
areas like the Middle East.
Abstract: In this paper a new algorithm to generate random
simple polygons from a given set of points in a two dimensional
plane is designed. The proposed algorithm uses a genetic algorithm to
generate polygons with few vertices. A new merge algorithm is
presented which converts any two polygons into a simple polygon.
This algorithm at first changes two polygons into a polygonal chain
and then the polygonal chain is converted into a simple polygon. The
process of converting a polygonal chain into a simple polygon is
based on the removal of intersecting edges. The experiments results
show that the proposed algorithm has the ability to generate a great
number of different simple polygons and has better performance in
comparison to celebrated algorithms such as space partitioning and
steady growth.
Abstract: In-memory database systems are becoming popular
due to the availability and affordability of sufficiently large RAM and
processors in modern high-end servers with the capacity to manage
large in-memory database transactions. While fast and reliable inmemory
systems are still being developed to overcome cache misses,
CPU/IO bottlenecks and distributed transaction costs, disk-based data
stores still serve as the primary persistence. In addition, with the
recent growth in multi-tenancy cloud applications and associated
security concerns, many organisations consider the trade-offs and
continue to require fast and reliable transaction processing of diskbased
database systems as an available choice. For these
organizations, the only way of increasing throughput is by improving
the performance of disk-based concurrency control. This warrants a
hybrid database system with the ability to selectively apply an
enhanced disk-based data management within the context of inmemory
systems that would help improve overall throughput.
The general view is that in-memory systems substantially
outperform disk-based systems. We question this assumption and
examine how a modified variation of access invariance that we call
enhanced memory access, (EMA) can be used to allow very high
levels of concurrency in the pre-fetching of data in disk-based
systems. We demonstrate how this prefetching in disk-based systems
can yield close to in-memory performance, which paves the way for
improved hybrid database systems. This paper proposes a novel EMA
technique and presents a comparative study between disk-based EMA
systems and in-memory systems running on hardware configurations
of equivalent power in terms of the number of processors and their
speeds. The results of the experiments conducted clearly substantiate
that when used in conjunction with all concurrency control
mechanisms, EMA can increase the throughput of disk-based systems
to levels quite close to those achieved by in-memory system. The
promising results of this work show that enhanced disk-based
systems facilitate in improving hybrid data management within the
broader context of in-memory systems.
Abstract: It is difficult to study the effect of various variables on
cycle fitting through actual experiment. To overcome such difficulty,
the forward dynamics of a musculoskeletal model was applied to cycle
fitting in this study. The measured EMG data weres compared with the
muscle activities of the musculoskeletal model through forward
dynamics. EMG data were measured from five cyclists who do not
have musculoskeletal diseases during three minutes pedaling with a
constant load (150 W) and cadence (90 RPM). The muscles used for
the analysis were the Vastus Lateralis (VL), Tibialis Anterior (TA),
Bicep Femoris (BF), and Gastrocnemius Medial (GM). Person’s
correlation coefficients of the muscle activity patterns, the peak timing
of the maximum muscle activities, and the total muscle activities were
calculated and compared. BIKE3D model of AnyBody (Anybodytech,
Denmark) was used for the musculoskeletal model simulation. The
comparisons of the actual experiments with the simulation results
showed significant correlations in the muscle activity patterns (VL:
0.789, TA: 0.503, BF: 0.468, GM: 0.670). The peak timings of the
maximum muscle activities were distributed at particular phases. The
total muscle activities were compared with the normalized muscle
activities, and the comparison showed about 10% difference in the VL
(+10%), TA (+9.7%), and BF (+10%), excluding the GM (+29.4%).
Thus, it can be concluded that muscle activities of model &
experiment showed similar results. The results of this study indicated
that it was possible to apply the simulation of further improved
musculoskeletal model to cycle fitting.
Abstract: This paper presents observations on the early
supervised internships in Psychology, currently called basic
internships in Brazil, and its importance in professional training. The
work is an experience report and focuses on the Professional training,
illustrated by the reality of a Brazilian institution, used as a case
study. It was developed from the authors' experience as academic
supervisors of this kind of practice throughout this undergraduate
course, combined with aspects investigated in the post-doctoral
research of one of them. Theoretical references on the subject and
related national legislation are analyzed, as well as reports of students
who experienced at least one semester of this type of practice,
articulated to the observations of the authors. The results demonstrate
the importance of the early supervised internships as a way of
creating opportunities for the students of a first contact with the
professional reality and the practice of psychologists in different
fields of insertion, preparing them for further experiments that require
more involvement in activities of training and practices in
Psychology.
Abstract: The study is devoted to define the optimal conditions
for the nitriding of pure iron at atmospheric pressure by using NH3-
Ar-C3H8 gas mixtures. After studying the mechanisms of phase
formation and mass transfer at the gas-solid interface, a mathematical
model is developed in order to predict the nitrogen transfer rate in the
solid, the ε-carbonitride layer growth rate and the nitrogen and
carbon concentration profiles. In order to validate the model and to
show its possibilities, it is compared with thermogravimetric
experiments, analyses and metallurgical observations (X-ray
diffraction, optical microscopy and electron microprobe analysis).
Results obtained allow us to demonstrate the sound correlation
between the experimental results and the theoretical predictions.
Abstract: Reburning is a useful technology in reducing nitric
oxide through injection of a secondary hydrocarbon fuel. In this paper,
an experimental study has been conducted to evaluate the effect of fuel
lean reburning on NOx/CO reduction in LNG flame. Experiments
were performed in flames stabilized by a co-flow swirl burner, which
was mounted at the bottom of the furnace. Tests were conducted using
LNG gas as the reburn fuel as well as the main fuel. The effects of
reburn fuel fraction and injection manner of the reburn fuel were
studied when the fuel lean reburning system was applied. The paper
reports data on flue gas emissions and temperature distribution in the
furnace for a wide range of experimental conditions. At steady state,
temperature distribution and emission formation in the furnace have
been measured and compared. This paper makes clear that in order to
decrease both NOx and CO concentrations in the exhaust when the
pulsated fuel lean reburning system was adapted, it is important that
the control of some factors such as frequency and duty ratio. Also it
shows the fuel lean reburning is also effective method to reduce NOx
as much as reburning.
Abstract: Recommendation systems are widely used in
e-commerce applications. The engine of a current recommendation
system recommends items to a particular user based on user
preferences and previous high ratings. Various recommendation
schemes such as collaborative filtering and content-based approaches
are used to build a recommendation system. Most of current
recommendation systems were developed to fit a certain domain such
as books, articles, and movies. We propose1 a hybrid framework
recommendation system to be applied on two dimensional spaces
(User × Item) with a large number of Users and a small number
of Items. Moreover, our proposed framework makes use of both
favorite and non-favorite items of a particular user. The proposed
framework is built upon the integration of association rules mining
and the content-based approach. The results of experiments show
that our proposed framework can provide accurate recommendations
to users.