Abstract: Sol-gel method has been used to fabricate
nanocomposite films on glass substrates composed halloysite clay
mineral and nanocrystalline TiO2. The methodology for the synthesis
involves a simple chemistry method utilized nonionic surfactant
molecule as pore directing agent along with the acetic acid-based solgel
route with the absence of water molecules. The thermal treatment
of composite films at 450oC ensures elimination of organic material
and lead to the formation of TiO2 nanoparticles onto the surface of
the halloysite nanotubes. Microscopy techniques and porosimetry
methods used in order to delineate the structural characteristics of the
materials. The nanocomposite films produced have no cracks and
active anatase crystal phase with small crystallite size were deposited
on halloysite nanotubes. The photocatalytic properties for the new
materials were examined for the decomposition of the Basic Blue 41
azo dye in solution. These, nanotechnology based composite films
show high efficiency for dye’s discoloration in spite of different
halloysite quantities and small amount of halloysite/TiO2 catalyst
immobilized onto glass substrates. Moreover, we examined the
modification of the halloysite/TiO2 films with silver particles in order
to improve the photocatalytic properties of the films. Indeed, the
presence of silver nanoparticles enhances the discoloration rate of the
Basic Blue 41 compared to the efficiencies obtained for unmodified
films.
Abstract: The purpose of this investigation is to relate the rain
power and the overland flow power to soil erodibility to assess the
effects of both parameters on soil erosion using variable rainfall
intensity on remoulded agricultural soil. Six rainfall intensities were
used to simulate the natural rainfall and are as follows: 12.4mm/h,
20.3mm/h, 28.6mm/h, 52mm/h, 73.5mm/h and 103mm/h. The results
have shown that the relationship between overland flow power and
rain power is best represented by a linear function (R2=0.99). As
regards the relationships between soil erodibility factor and rain and
overland flow powers, the evolution of both parameters with the
erodibility factor follow a polynomial function with high coefficient
of determination. From their coefficients of determination (R2=0.95)
for rain power and (R2=0.96) for overland flow power, we can
conclude that the flow has more power to detach particles than rain.
This could be explained by the fact that the presence of particles,
already detached by rain and transported by the flow, give the flow
more weight and then contribute to the detachment of particles by
collision.
Abstract: This paper presents the impact study of apparent
reactance injected by series Flexible AC Transmission System
(FACTS) i.e. Thyristor Controlled Series Reactor (TCSR) on the
measured impedance of a 400 kV single electrical transmission line
in the presence of phase to earth fault with fault resistance. The study
deals with an electrical transmission line of Eastern Algerian
transmission networks at Group Sonelgaz (Algerian Company of
Electrical and Gas) compensated by TCSR connected at midpoint of
the line. This compensator used to inject active and reactive powers
is controlled by three TCSR-s. The simulations results investigate the
impacts of the TCSR on the parameters of short circuit calculation
and parameters of measured impedance by distance relay in the
presence of earth fault for three cases study.
Abstract: The current speech interfaces in many military
applications may be adequate for native speakers. However,
the recognition rate drops quite a lot for non-native speakers
(people with foreign accents). This is mainly because the nonnative
speakers have large temporal and intra-phoneme
variations when they pronounce the same words. This
problem is also complicated by the presence of large
environmental noise such as tank noise, helicopter noise, etc.
In this paper, we proposed a novel continuous acoustic feature
adaptation algorithm for on-line accent and environmental
adaptation. Implemented by incremental singular value
decomposition (SVD), the algorithm captures local acoustic
variation and runs in real-time. This feature-based adaptation
method is then integrated with conventional model-based
maximum likelihood linear regression (MLLR) algorithm.
Extensive experiments have been performed on the NATO
non-native speech corpus with baseline acoustic model trained
on native American English. The proposed feature-based
adaptation algorithm improved the average recognition
accuracy by 15%, while the MLLR model based adaptation
achieved 11% improvement. The corresponding word error
rate (WER) reduction was 25.8% and 2.73%, as compared to
that without adaptation. The combined adaptation achieved
overall recognition accuracy improvement of 29.5%, and
WER reduction of 31.8%, as compared to that without
adaptation.
Abstract: Potassium monopersulfate has been decomposed in
aqueous solution in the presence of Co(II). The effect of the main
operating variables has been assessed. Minimum variations in pH
exert a considerable influence on the process kinetics. Thus, when no
pH adjustment is considered, the actual effect of variables like initial
monopersulfate and/or catalyst concentration may be hindered. As
expected, temperature enhances the monopersulfate decomposition
rate by following the Arrhenius law. The activation energy in the
proximity of 85 kJ/mol has been obtained. Amongst the different
solids tested in the monopersulfate decomposition, only the
perovskite LaTi0.15Cu0.85O3 has shown a significant catalytic activity.
Abstract: Categorical data based on description of the
agricultural landscape imposed some mathematical and analytical
limitations. This problem however can be overcome by data
transformation through coding scheme and the use of non-parametric
multivariate approach. The present study describes data
transformation from qualitative to numerical descriptors. In a
collection of 103 random soil samples over a 60 hectare field,
categorical data were obtained from the following variables: levels of
nitrogen, phosphorus, potassium, pH, hue, chroma, value and data on
topography, vegetation type, and the presence of rocks. Categorical
data were coded, and Spearman-s rho correlation was then calculated
using PAST software ver. 1.78 in which Principal Component
Analysis was based. Results revealed successful data transformation,
generating 1030 quantitative descriptors. Visualization based on the
new set of descriptors showed clear differences among sites, and
amount of variation was successfully measured. Possible applications
of data transformation are discussed.
Abstract: The rheological properties of light crude oil and its mixture with water were investigated experimentally. These rheological properties include steady flow behavior, yield stress, transient flow behavior, and viscoelastic behavior. A RheoStress RS600 rheometer was employed in all of the rheological examination tests. The light crude oil exhibits a Newtonian and for emulsion exhibits a non-Newtonian shear thinning behavior over the examined shear rate range of 0.1–120 s-1. In first time, a series of samples of crude oil from the Algerian Sahara has been tested and the results expressed in terms of τ=f(γ) have demonstrated their Newtonian character for the temperature included in [20°C, 70°C]. In second time and at T=20°C, the oil-water emulsions (30%, 50% and 70%) by volume of water), thermodynamically stable, have demonstrated a non-Newtonian rheological behavior that is to say, Herschel-Bulkley and Bingham types. For each type of crude oil-water emulsion, the rheological parameters are calculated by numerical treatment of results.
Abstract: Computer worm detection is commonly performed by
antivirus software tools that rely on prior explicit knowledge of the
worm-s code (detection based on code signatures). We present an
approach for detection of the presence of computer worms based on
Artificial Neural Networks (ANN) using the computer's behavioral
measures. Identification of significant features, which describe the
activity of a worm within a host, is commonly acquired from security
experts. We suggest acquiring these features by applying feature
selection methods. We compare three different feature selection
techniques for the dimensionality reduction and identification of the
most prominent features to capture efficiently the computer behavior
in the context of worm activity. Additionally, we explore three
different temporal representation techniques for the most prominent
features. In order to evaluate the different techniques, several
computers were infected with five different worms and 323 different
features of the infected computers were measured. We evaluated
each technique by preprocessing the dataset according to each one
and training the ANN model with the preprocessed data. We then
evaluated the ability of the model to detect the presence of a new
computer worm, in particular, during heavy user activity on the
infected computers.
Abstract: In this study, a low temperature sensor highly selective to CO in presence of methane is fabricated by using 4 nm SnO2 quantum dots (QDs) prepared by sonication assisted precipitation. SnCl4 aqueous solution was precipitated by ammonia under sonication, which continued for 2 h. A part of the sample was then dried and calcined at 400°C for 1.5 h and characterized by XRD and BET. The average particle size and the specific surface area of the SnO2 QDs as well as their sensing properties were compared with the SnO2 nano-particles which were prepared by conventional sol-gel method. The BET surface area of sonochemically as-prepared product and the one calcined at 400°C after 1.5 hr are 257 m2/gr and 212 m2/gr respectively while the specific surface area for SnO2 nanoparticles prepared by conventional sol-gel method is about 80m2/gr. XRD spectra revealed pure crystalline phase of SnO2 is formed for both as-prepared and calcined samples of SnO2 QDs. However, for the sample prepared by sol-gel method and calcined at 400°C SnO crystals are detected along with those of SnO2. Quantum dots of SnO2 show exceedingly high sensitivity to CO with different concentrations of 100, 300 and 1000 ppm in whole range of temperature (25- 350°C). At 50°C a sensitivity of 27 was obtained for 1000 ppm CO, which increases to a maximum of 147 when the temperature rises to 225°C and then drops off while the maximum sensitivity for the SnO2 sample prepared by the sol-gel method was obtained at 300°C with the amount of 47.2. At the same time no sensitivity to methane is observed in whole range of temperatures for SnO2 QDs. The response and recovery times of the sensor sharply decreases with temperature, while the high selectivity to CO does not deteriorate.
Abstract: The aim of this paper is to study the oblique
stagnation point flow on vertical plate with uniform surface heat flux
in presence of magnetic field. Using Stream function, partial
differential equations corresponding to the momentum and energy
equations are converted into non-linear ordinary differential
equations. Numerical solutions of these equations are obtained using
Runge-Kutta Fehlberg method with the help of shooting technique.
In the present work the effects of striking angle, magnetic field
parameter, Grashoff number, the Prandtl number on velocity and heat
transfer characteristics have been discussed. Effect of above
mentioned parameter on the position of stagnation point are also
studied.
Abstract: Three reactor types were explored and successfully
used for pigment production by Monascus: shake flasks, and shaken
and stirred miniaturized reactors. Also, the use of dielectric
spectroscopy for the on-line measurement of biomass levels was
explored. Shake flasks gave good pigment yields, but scale up is
difficult, and they cannot be automated. Shaken bioreactors were less
successful with pigment production than stirred reactors.
Experiments with different impeller speeds in different volumes of
liquid in the reactor confirmed that this is most likely due oxygen
availability. The availability of oxygen appeared to affect biomass
levels less than pigment production; red pigment production in
particular needed very high oxygen levels. Dielectric spectroscopy
was effectively used to continuously measure biomass levels during
the submerged fungal fermentation in the shaken and stirred
miniaturized bioreactors, despite the presence of the solid substrate
particles. Also, the capacitance signal gave useful information about
the viability of the cells in the culture.
Abstract: This paper evaluates the dividend payments for general
claim size distributions in the presence of a dividend barrier. The
surplus of a company is modeled using the classical risk process
perturbed by diffusion, and in addition, it is assumed to accrue interest
at a constant rate. After presenting the integro-differential equation
with initial conditions that dividend payments satisfies, the paper
derives a useful expression of the dividend payments by employing
the theory of Volterra equation. Furthermore, the optimal value of
dividend barrier is found. Finally, numerical examples illustrate the
optimality of optimal dividend barrier and the effects of parameters
on dividend payments.
Abstract: The Algorithm 2 for a n-link manipulator movement amidst arbitrary unknown static obstacles for a case when a sensor system supplies information about local neighborhoods of different points in the configuration space is presented. The Algorithm 2 guarantees the reaching of a target position in a finite number of steps. The Algorithm 2 is reduced to a finite number of calls of a subroutine for planning a trajectory in the presence of known forbidden states. The polynomial approximation algorithm which is used as the subroutine is presented. The results of the Algorithm2 implementation are given.
Abstract: Drinking water is one of the most valuable resources
available to mankind. The presence of pathogens in drinking water is
highly undesirable. Because of the Lateritic soil, the iron
concentrations were high in ground water. High concentration of iron
and other trace elements could restrict bacterial growth and modify
their metabolic pattern as well. The bacterial growth rate reduced in
the presence of iron in water. This paper presents the results of a
controlled laboratory study conducted to assess the inhibition of
micro-organism (pathogen) in well waters in the presence of
dissolved iron concentrations. Synthetic samples were studied in the
laboratory and the results compared with field samples. Predictive
model for microbial inhibition in the presence of iron is presented. It
was seen that the bore wells, open wells and the field results varied,
probably due to the nature of micro-organism utilizing the iron in
well waters.
Abstract: Although oil-based drilling fluids are of paramount practical and economical interest, they represent a serious source of pollution, once released into the environment as drill cuttings. The aim of this study is to assess the capability of isolated microorganisms to degrade gasoil fuel. The commonly used physicochemical and biodegradation remediation techniques of petroleum contaminated soil were both investigated. The study revealed that natural biodegradation is favorable. Even though, the presence of heavy metals, the moisture level of (8.55%) and nutrient deficiencies put severe constrains on microorganisms- survival ranges inhibiting the biodegradation process. The selected strains were able to degrade the diesel fuel at significantly high rates (around 98%).
Abstract: Diffuse viral encephalitis may lack fever and other cardinal signs of infection and hence its distinction from other acute encephalopathic illnesses is challenging. Often, the EEG changes seen routinely are nonspecific and reflect diffuse encephalopathic changes only. The aim of this study was to use nonlinear dynamic mathematical techniques for analyzing the EEG data in order to look for any characteristic diagnostic patterns in diffuse forms of encephalitis.It was diagnosed on clinical, imaging and cerebrospinal fluid criteria in three young male patients. Metabolic and toxic encephalopathies were ruled out through appropriate investigations. Digital EEGs were done on the 3rd to 5th day of onset. The digital EEGs of 5 male and 5 female age and sex matched healthy volunteers served as controls.Two sample t-test indicated that there was no statistically significant difference between the average values in amplitude between the two groups. However, the standard deviation (or variance) of the EEG signals at FP1-F7 and FP2-F8 are significantly higher for the patients than the normal subjects. The regularisation dimension is significantly less for the patients (average between 1.24-1.43) when compared to the normal persons (average between 1.41-1.63) for the EEG signals from all locations except for the Fz-Cz signal. Similarly the wavelet dimension is significantly less (P = 0.05*) for the patients (1.122) when compared to the normal person (1.458). EEGs are subdued in the case of the patients with presence of uniform patterns, manifested in the values of regularisation and wavelet dimensions, when compared to the normal person, indicating a decrease in chaotic nature.
Abstract: Terminal localization for indoor Wireless Local Area
Networks (WLANs) is critical for the deployment of location-aware
computing inside of buildings. A major challenge is obtaining high
localization accuracy in presence of fluctuations of the received signal
strength (RSS) measurements caused by multipath fading. This paper
focuses on reducing the effect of the distance-varying noise by spatial
filtering of the measured RSS. Two different survey point geometries
are tested with the noise reduction technique: survey points arranged
in sets of clusters and survey points uniformly distributed over the
network area. The results show that the location accuracy improves
by 16% when the filter is used and by 18% when the filter is applied
to a clustered survey set as opposed to a straight-line survey set.
The estimated locations are within 2 m of the true location, which
indicates that clustering the survey points provides better localization
accuracy due to superior noise removal.
Abstract: The concentrations of aliphatic and polycyclic aromatic hydrocarbons (PAH) were determined in atmospheric aerosol samples collected at a rural site in Hungary (K-puszta, summer 2008), a boreal forest (Hyytiälä,
April 2007) and a polluted rural area in Italy (San Pietro Capofiume, Po Valley, April 2008). A clear distinction between “clean" and “polluted" periods was observed. Concentrations obtained for Hyytiälä are significantly lower than those for the other two sites. Source reconciliation was performed using diagnostic parameters, such as the carbon preference index and ratios between PAH. The presence of an unresolved complex mixture of hydrocarbons, especially for the Finnish and Italian samples, is indicative of petrogenic inputs. In K-puszta, the aliphatic hydrocarbons are dominated by leaf wax n-alkanes. The long range transport of anthropogenic pollution contributed to the Finnish aerosol. Industrial activities and vehicular emissions represent major sources in San Pietro Capofiume. PAH in K-puszta consist of both pyrogenic and petrogenic compounds.
Abstract: We have investigated the effect of piezoelectric (PZ)
polarization property in binary as well as in ternary wurtzite nitrides.
It is found that with the presence of PZ polarization property, the
phonon group velocity is modified. The change in phonon group
velocity due to PZ polarization effect directly depends on
piezoelectric tensor value. Using different piezoelectric tensor values
recommended by different workers in the literature, percent change in
group velocities of phonons has been estimated. The Debye
temperatures and frequencies of binary nitrides GaN, AlN and InN
are also calculated using the modified group velocities. For ternary
nitrides AlxGa(1-x)N, InxGa(1-x)N and InxAl(1-x)N, the phonon group
velocities have been calculated as a functions of composition. A
small positive bowing is observed in phonon group velocities of
ternary alloys. Percent variations in phonon group velocities are also
calculated for a straightforward comparison among ternary nitrides.
The results are expected to show a change in phonon relaxation rates
and thermal conductivity of III-nitrides when piezoelectric
polarization property is taken into consideration.
Abstract: How to effectively allocate system resource to process
the Client request by Gateway servers is a challenging problem. In
this paper, we propose an improved scheme for autonomous
performance of Gateway servers under highly dynamic traffic loads.
We devise a methodology to calculate Queue Length and Waiting
Time utilizing Gateway Server information to reduce response time
variance in presence of bursty traffic. The most widespread
contemplation is performance, because Gateway Servers must offer
cost-effective and high-availability services in the elongated period,
thus they have to be scaled to meet the expected load. Performance
measurements can be the base for performance modeling and
prediction. With the help of performance models, the performance
metrics (like buffer estimation, waiting time) can be determined at
the development process. This paper describes the possible queue
models those can be applied in the estimation of queue length to
estimate the final value of the memory size. Both simulation and
experimental studies using synthesized workloads and analysis of
real-world Gateway Servers demonstrate the effectiveness of the
proposed system.