Abstract: This work presents a new planar multiband antenna
based on fractal geometry. This structure is optimized and validated
into simulation by using CST-MW Studio. To feed this antenna we
have used a CPW line which makes it easy to be incorporated with
integrated circuits. The simulation results presents a good matching
input impedance and radiation pattern in the GSM band at 900 MHz
and ISM band at 2.4 GHz. The final structure is a dual band fractal
antenna with 70 x 70 mm² as a total area by using an FR4 substrate.
Abstract: This paper presents a novel design of a microstrip
fractal antenna based on the use of Sierpinski triangle shape, it’s
designed and simulated by using FR4 substrate in the operating
frequency bands (GPS, WiMAX), the design is a fractal antenna with
a modified ground structure. The proposed antenna is simulated and
validated by using CST Microwave Studio Software, the simulated
results presents good performances in term of radiation pattern and
matching input impedance.
Abstract: Knowledge management is considered as an important
factor in improving health care services. KM facilitates the transfer of
existing knowledge and the development of new knowledge in
hospitals. This paper reviews practices adopted by doctors in Kuwait
for capturing, sharing, and generating knowledge. It also discusses
the perceived impact of KM practices on performance of hospitals.
Based on a survey of 277 doctors, the study found that KM practices
among doctors in the sampled hospitals were not very effective. Little
attention was paid to the main activities that support the transfer of
expertise among doctors in hospitals. However, as predicted by
previous studies, good km practices were perceived by doctors to
have a positive impact on performance of hospitals. It was concluded
that through effective KM practices hospitals could improve the
services they provide. Documentation of best practices and capturing
of lessons learnt for re-use of knowledge could help transform the
hospitals into learning organizations.
Abstract: To develop AZ91D magnesium alloys with improved
properties, we have applied TiN and VN/TiN multilayer coatings
using DC magnetron sputter technique. Coating structure, surface
morphology, chemical bonding and corrosion resistance of coatings
were analyzed by x-ray diffraction (XRD), scanning electron
microscope (SEM), x-ray photoelectron spectroscopy (XPS), and
tafel extrapolation method, respectively. XPS analysis reveal that VN
overlayer reacts with oxygen at the VN/TiN interface and forms more
stable TiN layer. Morphological investigations and the corrosion
results show that VN/TiN multilayer thin film coatings are quite
effective to optimize the corrosion resistance of Mg alloys.
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: This paper aims to represent the commercial activity
of a city taking as source data the social network Foursquare. The
city of Murcia is selected as case study, and the location-based
social network Foursquare is the main source of information. After
carrying out a reorganisation of the user-generated data extracted
from Foursquare, it is possible to graphically display on a map the
various city spaces and venues especially those related to commercial,
food and entertainment sector businesses. The obtained visualisation
provides information about activity patterns in the city of Murcia
according to the people‘s interests and preferences and, moreover,
interesting facts about certain characteristics of the town itself.
Abstract: The in-cylinder flow and mixture formations are
significant in view of today’s increasing concern on environmental
issues and stringent emission regulations. In this paper, the numerical
simulations of a SI engine at different engine speeds (2000-5000
rpm) at fixed intake flow pressure of 1 bar are studied using the AVL
FIRE software. The simulation results show that when the engine
speed at fixed intake flow pressure is increased, the volumetric
efficiency of the engine decreases. This is due to a richer fuel
conditions near the engine cylinder wall when engine speed is
increased. Significant effects of impingement are also noted on the
upper and side walls of the engine cylinder. These variations in
mixture formation before ignition could affect the thermodynamics
efficiency and specific fuel consumption that would lead to a reduced
engine performance.
Abstract: Soil erosion is a very complex phenomenon, resulting
from detachment and transport of soil particles by erosion agents.
The kinetic energy of raindrop is the energy available for detachment
and transport by splashing rain. The soil erodibility is defined as the
ability of soil to resist to erosion. For this purpose, an experimental
study was conducted in the laboratory using rainfall simulator to
study the effect of the kinetic energy of rain (Ec) on the soil
erodibility (K). The soil used was a sandy agricultural soil of 62.08%
coarse sand, 19.14% fine sand, 6.39% fine silt, 5.18% coarse silt and
7.21% clay. The obtained results show that the kinetic energy of
raindrops evolves as a power law with soil erodibility.
Abstract: The reliability of the filtered HVBK model is now
investigated via some large eddy simulations (LES) of freely
decaying isotropic superfluid turbulence. For homogeneous
turbulence at very high Reynolds numbers, comparison of the terms
in the spectral kinetic energy budget equation indicates, in the
energy-containing range, that the production and energy transfer
effects become significant except for dissipation. In the inertial range,
where the two fluids are perfectly locked, the mutual friction maybe
neglected with respect to other terms. Also, the LES results for the
other terms of the energy balance are presented.
Abstract: The hydrogenated amorphous carbon films (α-C:H)
were deposited on p-type Si (100) substrates at different thicknesses by
radio frequency plasma enhanced chemical vapor deposition
technique (rf-PECVD). Raman spectra display asymmetric
diamond-like carbon (DLC) peaks, representative of the α-C:H films.
The decrease of intensity ID/IG ratios revealed the sp3 content arise at
different thicknesses of the α-C:H films. In terms of mechanical
properties, the high hardness and elastic modulus values showed the
elastic and plastic deformation behaviors related to sp3 content in
amorphous carbon films. Electrochemical properties showed that the
α-C:H films exhibited excellent corrosion resistance in air-saturated
3.5 wt.% NaCl solution for pH 2 at room temperature. Thickness
increasing affected the small sp2 clusters in matrix, restricting the
velocity transfer and exchange of electrons. The deposited α-C:H films
exhibited excellent mechanical properties and corrosion resistance.
Abstract: In this paper a novel design of aerostatic thrust bearing
is proposed and is analyzed numerically. The capillary restrictor and
bearing disk are made of elastomer like silicone and PU. The
viscoelasticity of elastomer helps the capillary expand for more air
flux and at the same time, allows conicity of the bearing surface to
form when the air pressure is enhanced. Therefore the bearing has the
better ability of passive compensation. In the present example, as
compared with the typical model, the new designs can nearly double
the load capability and offer four times static stiffness.
Abstract: Aluminum hybrid reinforcement technology is a
response to the dynamic ever increasing service requirements of such
industries as transportation, aerospace, automobile, marine, etc. It is
unique in that it offers a platform of almost unending combinations of
materials to produce various hybrid composites. This article reviews
the studies carried out on various combinations of aluminum hybrid
composite and the effects on mechanical, physical and chemical
properties. It is observed that the extent of enhancement of these
properties of hybrid composites is strongly dependent on the nature
of the reinforcement, its hardness, particle size, volume fraction,
uniformity of dispersion within the matrix and the method of hybrid
production.
Abstract: The exposure to outdoor air pollution causes lung
cancer and increases the risk of bladder cancer. Because air pollution
in urban areas is mainly caused by transportation, it is necessary to
evaluate pollutant exhaust emissions from vehicles during their realworld
use. Nevertheless their evaluation and reduction is a key
problem, especially in the cities, that account for more than 50% of
world population.
A particular attention was given to the slope variability along the
streets during each journey performed by the instrumented vehicle.
In this paper we dealt with the problem of describing a
quantitatively approach for the reconstruction of GPS coordinates and
altitude, in the context of correlation study between driving cycles /
emission / geographical location, during an experimental campaign
realized with some instrumented cars.
Finally the slope analysis can be correlated to the emission and
consumption values in a specific road position, and it could be
evaluated its influence on their behaviour.
Abstract: Marine Protected Areas can benefit from nature based
tourism, monitoring environmental impacts and also become target
for human presence. From more than 3 million tourists visiting
Cozumel Island every year, an average of 2,8 million arrive by cruise
ship, and 41% are estimated to have motivation for water activities.
The destination is relying so much on the tourism activity, that scuba
diving and snorkeling in the National Park Reef of Cozumel sustain
the major economic activity. In order to achieve the sustainable
development indicator designed for regional environmental
development, the PNAC offers a training course to tourism providers
to access the protected area. This way, the update of the last 5 years
of such training is directed to diving staff, boat crew and
professionals, making them able to assist in managing the natural
resource. Moreover, the case study is an example to be used for
raising awareness among tourists visiting protected areas.
Abstract: Two micromechanical models for 3D smart composite
with embedded periodic or nearly periodic network of generally
orthotropic reinforcements and actuators are developed and applied to
cubic structures with unidirectional orientation of constituents.
Analytical formulas for the effective piezothermoelastic coefficients
are derived using the Asymptotic Homogenization Method (AHM).
Finite Element Analysis (FEA) is subsequently developed and used
to examine the aforementioned periodic 3D network reinforced smart
structures. The deformation responses from the FE simulations are
used to extract effective coefficients. The results from both
techniques are compared. This work considers piezoelectric materials
that respond linearly to changes in electric field, electric
displacement, mechanical stress and strain and thermal effects. This
combination of electric fields and thermo-mechanical response in
smart composite structures is characterized by piezoelectric and
thermal expansion coefficients. The problem is represented by unitcell
and the models are developed using the AHM and the FEA to
determine the effective piezoelectric and thermal expansion
coefficients. Each unit cell contains a number of orthotropic
inclusions in the form of structural reinforcements and actuators.
Using matrix representation of the coupled response of the unit cell,
the effective piezoelectric and thermal expansion coefficients are
calculated and compared with results of the asymptotic
homogenization method. A very good agreement is shown between
these two approaches.
Abstract: Pesticides and drugs used in agriculture and veterinary
medicine may end up in aquatic environments and bioaccumulate in
the food chain, thus causing serious problems for fauna and human
health. For determination of the toxic effects of atrazine herbicide on
Caspian kutum, Rutilus frisii kutum larvae, the 96-h LC50 of atrazine
was measured for newly hatched larvae as 18.53 ppm. Toxicity of
atrazine herbicide on Caspian kutum larvae was investigated using
concentrations: 9.25ppm, 4.62 ppm and 2.31 ppm for 7 days.
Comparison of the length, weight and condition factor showed that
no significant differences between atrazine exposed and control
groups. The concentration of Na+, K+, Ca2+, Mg2+ and Cl- in whole
body of larvae in control and atrazine exposure groups were
measured and the results showed that concentrations of all these ions
is higher in atrazine exposure group than control group. It is obvious
from this study that atrazine negatively affects osmoregulation
process and changes ion compositions of the body even at sublethal
concentration and acute exposure but have no effects on growth
parameters of the body.
Abstract: Hydrogenated amorphous carbon (a-C:H) films have
been synthesized by a radio frequency plasma enhanced chemical
vapor deposition (rf-PECVD) technique with different bias voltage
from 0.0 to -0.5 kV. The Raman spectra displayed the polymer-like
hydrogenated amorphous carbon (PLCH) film with 0.0 to -0.1 and
a-C:H films with -0.2 to -0.5 kV of bias voltages. The surface chemical
information of all films were studied by X-ray photoelectron
spectroscopy (XPS) technique, presented to C-C (sp2 and sp3) and C-O
bonds, and relative carbon (C) and oxygen (O) atomics contents. The
O contamination had affected on structure and optical properties. The
true density of PLCH and a-C:H films were characterized by X-ray
refractivity (XRR) method, showed the result as in the range of
1.16-1.73 g/cm3 that depending on an increasing of bias voltage. The
hardness was proportional to the true density of films. In addition, the
optical properties i.e. refractive index (n) and extinction coefficient (k)
of these films were determined by a spectroscopic ellipsometry (SE)
method that give formation to in 1.62-2.10 (n) and 0.04-0.15 (k)
respectively. These results indicated that the optical properties
confirmed the Raman results as presenting the structure changed with
applied bias voltage increased.
Abstract: In our paper we describe the security capabilities of
data collection. Data are collected with probes located in the near and
distant surroundings of the company. Considering the numerous
obstacles e.g. forests, hills, urban areas, the data collection is realized
in several ways. The collection of data uses connection via wireless
communication, LAN network, GSM network and in certain areas
data are collected by using vehicles. In order to ensure the connection
to the server most of the probes have ability to communicate in
several ways. Collected data are archived and subsequently used in
supervisory applications.
To ensure the collection of the required data, it is necessary to
propose algorithms that will allow the probes to select suitable
communication channel.
Abstract: The objectives of this study is to investigate the
existence of the sticky cost behavior of firms listed in the Indonesia
Stock Exchange (IDX) and to find evidence on the effects of sticky
operating expenses (SG&A expenses) on profitability of firms. For
the first objective, this study finds that the sticky cost behavior does
exist. For the second objective, this study finds that the stickier the
operating expenses the lesser future profitability of the firms. This
study concludes that sticky cost affects negatively to the performance
and, therefore, firms should include flexibility in designing the cost
structure of their firms.
Abstract: Recently, an increasing number of researchers have
been focusing on working out realistic solutions to sustainability
problems. As sustainability issues gain higher importance for
organisations, the management of such decisions becomes critical.
Knowledge representation is a fundamental issue of complex
knowledge based systems. Many types of sustainability problems
would benefit from models based on experts’ knowledge. Cognitive
maps have been used for analyzing and aiding decision making. A
cognitive map can be made of almost any system or problem. A
fuzzy cognitive map (FCM) can successfully represent knowledge
and human experience, introducing concepts to represent the essential
elements and the cause and effect relationships among the concepts to
model the behaviour of any system. Integrated waste management
systems (IWMS) are complex systems that can be decomposed to
non-related and related subsystems and elements, where many factors
have to be taken into consideration that may be complementary,
contradictory, and competitive; these factors influence each other and
determine the overall decision process of the system. The goal of the
present paper is to construct an efficient IWMS which considers
various factors. The authors’ intention is to propose an expert based
system design approach for implementing expert decision support in
the area of IWMSs and introduces an appropriate methodology for
the development and analysis of group FCM. A framework for such a
methodology consisting of the development and application phases is
presented.