Abstract: Synthesis of gold nanoparticles has attracted much
attention since the pioneering discovery of the high catalytic activity
of supported gold nanoparticles in the reaction of CO oxidation at
low temperature. In this research field, we used Na-montmorillonite
for gold nanoparticles stabilization; various gold loading percentage
1, 2 and 5% were used for gold nanoparticles preparation. The gold
nanoparticles were obtained using chemical reduction method using
NaBH4 as reductant agent. The obtained gold nanoparticles stabilized
in Na-montmorillonite were used as catalysts for the reduction of 4-
nitrophenol to aminophenol with sodium borohydride at room
temperature. The UV-Vis results confirmed directly the gold
nanoparticles formation. The XRD and N2 adsorption results showed
the formation of gold nanoparticles in the pores of montmorillonite
with an average size of 5 nm obtained on samples with 2% gold
loading percentage. The gold particles size increased with the
increase of gold loading percentage. The reduction reaction of 4-
nitrophenol into 4-aminophenol with NaBH4 catalyzed by Au-Namontmorillonite
catalyst exhibits remarkably a high activity; the
reaction was completed within 9 min for 1%Au-Na-montmorillonite
and within 3 min for 2%Au-Na-montmorillonite.
Abstract: Wireless Sensor Networks (WSNs) enable new
applications and need non-conventional paradigms for the protocol
because of energy and bandwidth constraints, In WSN, sensor node’s
life is a critical parameter. Research on life extension is based on
Low-Energy Adaptive Clustering Hierarchy (LEACH) scheme,
which rotates Cluster Head (CH) among sensor nodes to distribute
energy consumption over all network nodes. CH selection in WSN
affects network energy efficiency greatly. This study proposes an
improved CH selection for efficient data aggregation in sensor
networks. This new algorithm is based on Bacterial Foraging
Optimization (BFO) incorporated in LEACH.
Abstract: The microstrip antennas area has seen some inventive
work in recent years and is now one of the most dynamic fields of
antenna theory. A novel and simple wideband monopole antenna is
presented printed on a single dielectric substrate which is fed by a 50
ohm microstrip line having a low-profile antenna structure with two
parallel s-shaped meandered line of same size. This antenna is fed by
a coaxial feeding tube. In this research, S–form microstrip patch antenna is designed from
measuring the prototypes of the proposed antenna one available
bands with 10db return loss bandwidths of about GPS application
(GPS L2 1490 MHz) and covering the 1400 to 1580 MHz frequency
band at 1.5 GHz, the simulated results for main parameters such as
return loss, impedance bandwidth, radiation patterns, and gains are
also discussed herein. The modeling study shows that such antennas,
in simplicity design and supply, can satisfy GPS application. Two
parallel slots are incorporated to disturb the surface flow path,
introducing local inductive effect. This antenna is fed by a coaxial
feeding tube.
Abstract: This study analyzes the critical gaps in the
architecture of European stability and the expected role of the
banking union as the new important step towards completing the
Economic and Monetary Union that should enable the creation of
safe and sound financial sector for the euro area market. The single
rulebook together with the Single Supervisory Mechanism and the
Single Resolution Mechanism - as two main pillars of the banking
union, should provide a consistent application of common rules and
administrative standards for supervision, recovery and resolution of
banks – with the final aim of replacing the former bail-out practice
with the bail-in system through which possible future bank failures
would be resolved by their own funds, i.e. with minimal costs for
taxpayers and real economy. In this way, the vicious circle between
banks and sovereigns would be broken. It would also reduce the
financial fragmentation recorded in the years of crisis as the result of
divergent behaviors in risk premium, lending activities and interest
rates between the core and the periphery. In addition, it should
strengthen the effectiveness of monetary transmission channels, in
particular the credit channels and overflows of liquidity on the money
market which, due to the fragmentation of the common financial
market, has been significantly disabled in period of crisis. However,
contrary to all the positive expectations related to the future
functioning of the banking union, major findings of this study
indicate that characteristics of the economic system in which the
banking union will operate should not be ignored. The euro area is an
integration of strong and weak entities with large differences in
economic development, wealth, assets of banking systems, growth
rates and accountability of fiscal policy. The analysis indicates that
low and unbalanced economic growth remains a challenge for the
maintenance of financial stability and this problem cannot be
resolved just by a single supervision. In many countries bank assets
exceed their GDP by several times and large banks are still a matter
of concern, because of their systemic importance for individual
countries and the euro zone as a whole. The creation of the Single
Supervisory Mechanism and the Single Resolution Mechanism is a
response to the European crisis, which has particularly affected
peripheral countries and caused the associated loop between the
banking crisis and the sovereign debt crisis, but has also influenced
banks’ balance sheets in the core countries, as the result of crossborder
capital flows. The creation of the SSM and the SRM should
prevent the similar episodes to happen again and should also provide
a new opportunity for strengthening of economic and financial
systems of the peripheral countries. On the other hand, there is a
potential threat that future focus of the ECB, resolution mechanism
and other relevant institutions will be extremely oriented towards
large and significant banks (whereby one half of them operate in the
core and most important euro area countries), and therefore it remains
questionable to what extent will the common resolution funds will be used for rescue of less important institutions. Recent geopolitical
developments will be the optimal indicator to show whether the
previously established mechanisms are sufficient enough to maintain
the adequate financial stability in the euro area market.
Abstract: In this study, a multi objective optimization for end
milling of Al 6061 alloy has been presented to provide better
surface quality and higher Material Removal Rate (MRR). The input
parameters considered for the analysis are spindle speed, depth of cut
and feed. The experiments were planned as per Taguchis design of
experiment, with L27 orthogonal array. The Grey Relational Analysis
(GRA) has been used for transforming multiple quality responses
into a single response and the weights of the each performance
characteristics are determined by employing the Principal Component
Analysis (PCA), so that their relative importance can be properly and
objectively described. The results reveal that Taguchi based G-PCA
can effectively acquire the optimal combination of cutting parameters.
Abstract: This paper presents a power control for a Doubly Fed
Induction Generator (DFIG) using in Wind Energy Conversion
System (WECS) connected to the grid. The proposed control strategy
employs two nonlinear controllers, Backstipping (BSC) and slidingmode
controller (SMC) scheme to directly calculate the required
rotor control voltage so as to eliminate the instantaneous errors of
active and reactive powers. In this paper the advantages of BSC and
SMC are presented, the performance and robustness of this two
controller’s strategy are compared between them. First, we present a
model of wind turbine and DFIG machine, then a synthesis of the
controllers and their application in the DFIG power control.
Simulation results on a 1.5MW grid-connected DFIG system are
provided by MATLAB/Simulink.
Abstract: A flow column has been innovatively used in the
design of a new electrocoagulation reactor (ECR1) that will reduce
the temperature of water being treated; where the flow columns work
as a radiator for the water being treated. In order to investigate the
performance of ECR1 and compare it to that of traditional reactors;
600 mL water samples with an initial temperature of 350C were
pumped continuously through these reactors for 30 min at current
density of 1 mA/cm2. The temperature of water being treated was
measured at 5 minutes intervals over a 30 minutes period using a
thermometer. Additional experiments were commenced to investigate
the effects of initial temperature (15-350C), water conductivity (0.15
– 1.2 S) and current density (0.5 -3 mA/cm2) on the performance of
ECR1.
The results obtained demonstrated that the ECR1, at a current
density of 1 mA/cm2 and continuous flow model, reduced water
temperature from 350C to the vicinity of 280C during the first 15
minutes and kept the same level till the end of the treatment time.
While, the temperature increased from 28.1 to 29.80C and from 29.8
to 31.90C in the batch and the traditional continuous flow models
respectively. In term of initial temperature, ECR1 maintained the
temperature of water being treated within the range of 22 to 280C
without the need for external cooling system even when the initial
temperatures varied over a wide range (15 to 350C). The influent
water conductivity was found to be a significant variable that affect
the temperature. The desirable value of water conductivity is 0.6 S.
However, it was found that the water temperature increased rapidly
with a higher current density.
Abstract: Feature selection has been used in many fields such as
classification, data mining and object recognition and proven to be
effective for removing irrelevant and redundant features from the
original dataset. In this paper, a new design of distributed intrusion
detection system using a combination feature selection model based
on bees and decision tree. Bees algorithm is used as the search
strategy to find the optimal subset of features, whereas decision tree
is used as a judgment for the selected features. Both the produced
features and the generated rules are used by Decision Making Mobile
Agent to decide whether there is an attack or not in the networks.
Decision Making Mobile Agent will migrate through the networks,
moving from node to another, if it found that there is an attack on one
of the nodes, it then alerts the user through User Interface Agent or
takes some action through Action Mobile Agent. The KDD Cup 99
dataset is used to test the effectiveness of the proposed system. The
results show that even if only four features are used, the proposed
system gives a better performance when it is compared with the
obtained results using all 41 features.
Abstract: As the Silicon oxide scaled down in MOSFET
technology to few nanometers, gate Direct Tunneling (DT) in
Floating gate (FGMOSFET) devices has become a major concern for
analog designers. FGMOSFET has been used in many low-voltage
and low-power applications, however, there is no accurate model that
account for DT gate leakage in nano-scale. This paper studied and
analyzed different simulation models for FGMOSFET using TSMC
90-nm technology. The simulation results for FGMOSFET cascade
current mirror shows the impact of DT on circuit performance in
terms of current and voltage without the need for fabrication. This
works shows the significance of using an accurate model for
FGMOSFET in nan-scale technologies.
Abstract: DNA analysis has been widely accepted as providing
valuable evidence concerning the identity of the source of biological
traces. Our work has showed that DNA samples can survive on
cartridges even after firing. The study also raised the possibility of
determining other information such as the age of the donor. Such
information may be invaluable in certain cases where spent cartridges
from automatic weapons are left behind at the scene of a crime. In
spite of the nature of touch evidence and exposure to high chamber
temperatures during shooting, we were still capable to retrieve
enough DNA for profile typing. In order to estimate age of
contributor, DNA methylation levels were analyzed using EpiTect
system for retrieved DNA. However, results were not conclusive, due
to low amount of input DNA.
Abstract: Establishing a secure communication of Internet
conferences for participants is very important. Before starting the
conference, all the participants establish a common conference key to
encrypt/decrypt communicated messages. It enables participants to
exchange the secure messages. Nevertheless, in the conference, if
there are any malicious participants who may try to upset the key
generation process causing other legal participants to obtain a different
conference key. In this article, we propose an improved conference
key agreement with fault-tolerant capability. The proposed scheme
can filter malicious participants at the beginning of the conference to
ensure that all participants obtain the same conference key. Compare
with other schemes, our scheme is more secure and efficient than
others.
Abstract: Geographical routing protocol requires node physical
location information to make forwarding decision. Geographical
routing uses location service or position service to obtain the position
of a node. The geographical information is a geographic coordinates
or can be obtained through reference points on some fixed coordinate
system. Link can be formed between two nodes. Link lifetime plays a
crucial role in MANET. Link lifetime represent how long the link is
stable without any failure between the nodes. Link failure may occur
due to mobility and because of link failure energy of nodes can be
drained. Thus this paper proposes survey about link lifetime
prediction using geographical information.
Abstract: Tannase (tannin acyl hydrolase, E.C.3.1.1.20) is an
important hydrolysable enzyme with innumerable applications and
industrial potential. In the present study, a kinetic model has been
developed for the batch fermentation used for the production of
tannase by A.flavus MTCC 3783. Maximum tannase activity of
143.30 U/ml was obtained at 96 hours under optimum operating
conditions at 35oC, an initial pH of 5.5 and with an inducer tannic
acid concentration of 3% (w/v) for a fermentation period of 120
hours. The biomass concentration reaches a maximum of 6.62 g/l at
96 hours and further there was no increase in biomass concentration
till the end of the fermentation. Various unstructured kinetic models
were analyzed to simulate the experimental values of microbial
growth, tannase activity and substrate concentration. The Logistic
model for microbial growth , Luedeking - Piret model for production
of tannase and Substrate utilization kinetic model for utilization of
substrate were capable of predicting the fermentation profile with
high coefficient of determination (R2) values of 0.980, 0.942 and
0.983 respectively. The results indicated that the unstructured models
were able to describe the fermentation kinetics more effectively.
Abstract: Mobile Ad hoc Network is a set of self-governing
nodes which communicate through wireless links. Dynamic topology
MANETs makes routing a challenging task. Various routing
protocols are there, but due to various fundamental characteristic
open medium, changing topology, distributed collaboration and
constrained capability, these protocols are tend to various types of
security attacks. Black hole is one among them. In this attack,
malicious node represents itself as having the shortest path to the
destination but that path not even exists. In this paper, we aim to
develop a routing protocol for detection and prevention of black hole
attack by modifying AODV routing protocol. This protocol is able to
detect and prevent the black hole attack. Simulation is done using
NS-2, which shows the improvement in network performance.
Abstract: File sharing in networks is generally achieved using
Peer-to-Peer (P2P) applications. Structured P2P approaches are
widely used in adhoc networks due to its distributed and scalability
features. Efficient mechanisms are required to handle the huge
amount of data distributed to all peers. The intrinsic characteristics of
P2P system makes for easier content distribution when compared to
client-server architecture. All the nodes in a P2P network act as both
client and server, thus, distributing data takes lesser time when
compared to the client-server method. CHORD protocol is a resource
routing based where nodes and data items are structured into a 1-
dimensional ring. The structured lookup algorithm of Chord is
advantageous for distributed P2P networking applications. However,
structured approach improves lookup performance in a high
bandwidth wired network it could contribute to unnecessary overhead
in overlay networks leading to degradation of network performance.
In this paper, the performance of existing CHORD protocol on
Wireless Mesh Network (WMN) when nodes are static and dynamic
is investigated.
Abstract: This paper presents the results obtained by numerical
simulation using the software ANSYS CFX-CFD for the air
pollutants dispersion in the atmosphere coming from the evacuation
of combustion gases resulting from the fuel combustion in an electric
thermal power plant. The model uses the Navier-Stokes equation to
simulate the dispersion of pollutants in the atmosphere. It is
considered as important factors in elaboration of simulation the
atmospheric conditions (pressure, temperature, wind speed, wind
direction), the exhaust velocity of the combustion gases, chimney
height and the obstacles (buildings). Using the air quality monitoring
stations it is measured the concentrations of main pollutants (SO2,
NOx and PM). The pollutants were monitored over a period of 3
months, after that the average concentration are calculated, which is
used by the software. The concentrations are: 8.915 μg/m3 (NOx),
9.587 μg/m3 (SO2) and 42 μg/m3 (PM). A comparison of test data
with simulation results demonstrated that CFX was able to describe
the dispersion of the pollutant as well the concentration of this
pollutants in the atmosphere.
Abstract: The purpose of this study is the discrimination of 28
postmenopausal with osteoporotic femoral fractures from an agematched
control group of 28 women using texture analysis based on
fractals. Two pre-processing approaches are applied on radiographic
images; these techniques are compared to highlight the choice of the
pre-processing method. Furthermore, the values of the fractal
dimension are compared to those of the fractal signature in terms of
the classification of the two populations. In a second analysis, the
BMD measure at proximal femur was compared to the fractal
analysis, the latter, which is a non-invasive technique, allowed a
better discrimination; the results confirm that the fractal analysis of
texture on calcaneus radiographs is able to discriminate osteoporotic
patients with femoral fracture from controls. This discrimination was
efficient compared to that obtained by BMD alone. It was also
present in comparing subgroups with overlapping values of BMD.
Abstract: In this paper comprehensive studies have been carried
out for the design optimization of a waste heat recovery system for
effectively utilizing the domestic air conditioner heat energy for
producing hot water. Numerical studies have been carried for the
geometry optimization of a waste heat recovery system for domestic
air conditioners. Numerical computations have been carried out using
a validated 2d pressure based, unsteady, 2nd-order implicit, SST k-ω
turbulence model. In the numerical study, a fully implicit finite
volume scheme of the compressible, Reynolds-Averaged, Navier-
Stokes equations is employed. At identical inflow and boundary
conditions various geometries were tried and effort has been taken for
proposing the best design criteria. Several combinations of pipe line
shapes viz., straight and spiral with different number of coils for the
radiator have been attempted and accordingly the design criteria has
been proposed for the waste heat recovery system design. We have
concluded that, within the given envelope, the geometry optimization
is a meaningful objective for getting better performance of waste heat
recovery system for air conditioners.
Abstract: Propagation of arbitrary amplitude nonlinear Alfven
waves has been investigated in low but finite β electron-positron-ion
plasma including full ion dynamics. Using Sagdeev pseudopotential
method an energy integral equation has been derived. The Sagdeev
potential has been calculated for different plasma parameters and it
has been shown that inclusion of ion parallel motion along the
magnetic field changes the nature of slow shear Alfven wave solitons
from dip type to hump type. The effects of positron concentration,
plasma-β and obliqueness of the wave propagation on the solitary
wave structure have also been examined.
Abstract: A solution methodology without using integral
transformation is proposed to develop analytical solutions for
transient heat conduction in nonuniform hollow cylinders with
time-dependent boundary condition at the outer surface. It is shown
that if the thermal conductivity and the specific heat of the medium
are in arbitrary polynomial function forms, the closed solutions of the
system can be developed. The influence of physical properties on the
temperature distribution of the system is studied. A numerical
example is given to illustrate the efficiency and the accuracy of the
solution methodology.