Abstract: A two-dimensional numerical simulation of the contribution
of both inertial and aerodynamic forces on the blade loads of
a Vertical-Axis Wind Turbine (VAWT) is presented. After describing
the computational model and the relative validation procedure, a
complete campaign of simulations - based on full RANS unsteady
calculations - is proposed for a three-bladed rotor architecture characterized
by a NACA 0021 airfoil. For each analyzed angular velocity,
the combined effect of pressure and viscous forces acting on every
rotor blade are compared to the corresponding centrifugal forces,
due to the revolution of the turbine, thus achieving a preliminary
estimation of the correlation between overall rotor efficiency and
structural blade loads.
Abstract: Support vector machines (SVMs) have shown
superior performance compared to other machine learning techniques,
especially in classification problems. Yet one limitation of SVMs is
the lack of an explanation capability which is crucial in some
applications, e.g. in the medical and security domains. In this paper, a
novel approach for eclectic rule-extraction from support vector
machines is presented. This approach utilizes the knowledge acquired
by the SVM and represented in its support vectors as well as the
parameters associated with them. The approach includes three stages;
training, propositional rule-extraction and rule quality evaluation.
Results from four different experiments have demonstrated the value
of the approach for extracting comprehensible rules of high accuracy
and fidelity.
Abstract: In this study, the contact problem of a layered composite which consists of two materials with different elastic constants and heights resting on two rigid flat supports with sharp edges is considered. The effect of gravity is neglected. While friction between the layers is taken into account, it is assumed that there is no friction between the supports and the layered composite so that only compressive tractions can be transmitted across the interface. The layered composite is subjected to a uniform clamping pressure over a finite portion of its top surface. The problem is reduced to a singular integral equation in which the contact pressure is the unknown function. The singular integral equation is evaluated numerically and the results for various dimensionless quantities are presented in graphical forms.
Abstract: In this paper, a multi-agent robot system is presented. The system consists of four robots. The developed robots are able to automatically enter and patrol a harmful environment, such as the building infected with virus or the factory with leaking hazardous gas. Further, every robot is able to perform obstacle avoidance and search for the victims. Several operation modes are designed: remote control, obstacle avoidance, automatic searching, and so on.
Abstract: In this paper, all-optical signal processors that perform
both microwave mixing and bandpass filtering in a radio-over-fiber
(RoF) link are presented. The key device is a Mach-Zehnder
modulator (MZM) which performs all-optical microwave mixing. An
up-converted microwave signal is obtained and other unwanted
frequency components are suppressed at the end of the fiber span.
Abstract: Ethanol has been known for a long time, being
perhaps the oldest product obtained through traditional biotechnology
fermentation. Agriculture waste as substrate in fermentation is vastly
discussed as alternative to replace edible food and utilization of
organic material. Pineapple peel, highly potential source as substrate
is a by-product of the pineapple processing industry. Bio-ethanol
from pineapple (Ananas comosus) peel extract was carried out by
controlling fermentation without any treatment. Saccharomyces
ellipsoides was used as inoculum in this fermentation process as it is
naturally found at the pineapple skin. In this study, the capability of
Response Surface Methodology (RSM) for optimization of ethanol
production from pineapple peel extract using Saccharomyces
ellipsoideus in batch fermentation process was investigated. Effect of
five test variables in a defined range of inoculum concentration 6-
14% (v/v), pH (4.0-6.0), sugar concentration (14-22°Brix),
temperature (24-32°C) and time of incubation (30-54 hrs) on the
ethanol production were evaluated. Data obtained from experiment
were analyzed with RSM of MINITAB Software (Version 15)
whereby optimum ethanol concentration of 8.637% (v/v) was
determined. The optimum condition of 14% (v/v) inoculum
concentration, pH 6, 22°Brix, 26°C and 30hours of incubation. The
significant regression equation or model at the 5% level with
correlation value of 99.96% was also obtained.
Abstract: In a bi-fuel diesel engine, the carburetor plays a vital
role in switching from fuel gas to petrol mode operation and viceversa.
The carburetor is the most important part of the fuel system of
a diesel engine. All diesel engines carry variable venturi mixer
carburetors. The basic operation of the carburetor mainly depends on
the restriction barrel called the venturi. When air flows through the
venturi, its speed increases and its pressure decreases. The main
challenge focuses on designing a mixing device which mixes the
supplied gas is the incoming air at an optimum ratio. In order to
surmount the identified problems, the way fuel gas and air flow in
the mixer have to be analyzed. In this case, the Computational Fluid
Dynamics or CFD approach is applied in design of the prototype
mixer. The present work is aimed at further understanding of the air
and fuel flow structure by performing CFD studies using a software
code. In this study for mixing air and gas in the condition that has
been mentioned in continuance, some mixers have been designed.
Then using of computational fluid dynamics, the optimum mixer has
been selected. The results indicated that mixer with 12 holes can
produce a homogenous mixture than those of 8-holes and 6-holes
mixer. Also the result showed that if inlet convergency was smoother
than outlet divergency, the mixture get more homogenous, the reason
of that is in increasing turbulence in outlet divergency.
Abstract: Vapour recompression system has been used to
enhance reduction in energy consumption and improvement in
energy effectiveness of distillation columns. However, the effects of
certain parameters have not been taken into consideration. One of
such parameters is the column heat loss which has either been
assumed to be a certain percent of reboiler heat transfer or negligible.
The purpose of this study was to evaluate the heat loss from an
ethanol-water vapour recompression distillation column with
pressure increase across the compressor (VRCAS) and compare the
results obtained and its effect on some parameters in similar system
(VRCCS) where the column heat loss has been assumed or neglected.
Results show that the heat loss evaluated was higher when compared
with that obtained for the column VRCCS. The results also showed
that increase in heat loss could have significant effect on the total
energy consumption, reboiler heat transfer, the number of trays and
energy effectiveness of the column.
Abstract: The production of activated carbon from low or zero cost of agricultural by-products or wastes has received great attention from academics and practitioners due to its economic and environmental benefits. In the production of bamboo furniture, a significant amount of bamboo waste is inevitably generated. Therefore, this research aimed to prepare activated carbons from bamboo furniture waste by chemical (KOH) activation and determine their properties and adsorption capacities for water treatment. The influence of carbonization time on the properties and adsorption capacities of activated carbons was also investigated. The finding showed that the bamboo-derived activated carbons had microporous characteristics. They exhibited high tendency for the reduction of impurities present in effluent water. Their adsorption capacities were comparable to the adsorption capacity of a commercial activated carbon regarding to the reduction in COD, TDS and turbidity of the effluent water.
Abstract: Traffic density, an indicator of traffic
conditions, is one of the most critical characteristics to
Intelligent Transport Systems (ITS). This paper investigates
recursive traffic density estimation using the information
provided from inductive loop detectors. On the basis of the
phenomenological relationship between speed and density, the
existing studies incorporate a state space model and update the
density estimate using vehicular speed observations via the
extended Kalman filter, where an approximation is made
because of the linearization of the nonlinear observation
equation. In practice, this may lead to substantial estimation
errors. This paper incorporates a suitable transformation to
deal with the nonlinear observation equation so that the
approximation is avoided when using Kalman filter to
estimate the traffic density. A numerical study is conducted. It
is shown that the developed method outperforms the existing
methods for traffic density estimation.
Abstract: An electronic portal image device (EPID) has become
a method of patient-specific IMRT dose verification for radiotherapy.
Research studies have focused on pre and post-treatment verification,
however, there are currently no interventional procedures using EPID
dosimetry that measure the dose in real time as a mechanism to
ensure that overdoses do not occur and underdoses are detected as
soon as is practically possible. As a result, an EPID-based real time
dose verification system for dynamic IMRT was developed and was
implemented with MATLAB/Simulink. The EPID image acquisition
was set to continuous acquisition mode at 1.4 images per second. The
system defined the time constraint gap, or execution gap at the image
acquisition time, so that every calculation must be completed before
the next image capture is completed. In addition, the
Abstract: The purpose of this study was to investigate the
response of the newly released Gafchromic HD-V2 film for alpha
particle of 5.5 MeV. Gafchromic HD-V2 was exposed to alpha
particles of energy 5 MeV from 241Am for different durations. Then
the films were scanned with a flatbed scanner. The dose response
curve up to 2200 Gy has been achieved. The film’s reproducibility
and sensitivity were evaluated. The results obtained show that the net
optical density increases almost exponentially with the increase in the
exposure time, and it becomes saturated after prolonged exposure
times. The red channel shows the highest sensitivity, with a value of
4 x 10-3 Gy-1 at netOD of 0.4. The inter-film reproducibility was
measured and the relative uncertainty found was 1.7 %, 2.1 % and 2.3
% for grey, red and green channels, respectively.
Abstract: The curves, of which the square of the distance
between the two points equal to zero, are called minimal or isotropic
curves [4]. In this work, first, necessary and sufficient conditions to
be a Pseudo Helix, which is a special case of such curves, are
presented. Thereafter, it is proven that an isotropic curve-s position
vector and pseudo curvature satisfy a vector differential equation of
fourth order. Additionally, In view of solution of mentioned
equation, position vector of pseudo helices is obtained.
Abstract: A new supported liquid membrane (SLM) system for
the selective transport of VO2
+ ions was prepared in this present
work. The SLM was a thin porous polyvinylidene difluoride
(PVDF) membrane soaked with Di-(2-ethylhexyl) phosphoric acid
(D2EHPA) as mobile carrier in Xylene as organic solvent.
D2EHPA acts as a highly selective carrier for the uphill transport of
VO2
+ ions through the SLM. The transport of VO2
+ ions reached to
64%. In the presence of P2O7-2 ion as suitable masking agent in the
feed solution, the interfering effects of other cations were eliminated.
Abstract: Added stresses due to adjacent structure should be
considered in foundation design and stress control in soil under the structure. This case is considered less than other cases in design and
calculation whereas stresses in implementation are greater than analytical stress.
Structure load are transmitted to earth by foundation and role of foundation is propagation of load on the continuous and half extreme
soil. This act cause that, present stresses lessen to allowable strength
of soil. Some researchers such as Boussinesq and westergaurd by
using of some assumption studied on this issue, theorically. Target of
this paper is study and evaluation of added stresses under structure
due to adjacent structure. For this purpose, by using of assumption, theoric relation and numeral methods, effects of adjacent structure
with 4 to 10 storeys on the main structure with 4 storeys are studied
and effect of parameters and sensitivity of them are evaluated.
Abstract: This paper reports on investigations into capacity of a
Multiple Input Multiple Output (MIMO) wireless communication
system employing a uniform linear array (ULA) at the transmitter and
either a uniform linear array (ULA) or a uniform circular array (UCA)
antenna at the receiver. The transmitter is assumed to be surrounded by
scattering objects while the receiver is postulated to be free from
scattering objects. The Laplacian distribution of angle of arrival
(AOA) of a signal reaching the receiver is postulated. Calculations of
the MIMO system capacity are performed for two cases without and
with the channel estimation errors. For estimating the MIMO channel,
the scaled least square (SLS) and minimum mean square error
(MMSE) methods are considered.
Abstract: The basis of examines is survey of 500 in the years
2002-2010, which was selected according to homogeneity of land
cover and where 1090 revenues were evaluated. For achieved yields
of winter wheat is obtained multicriterial regression function
depending on the major factors influencing the consumption of
nitrogen. The coefficient of discrimination of the established model is
0.722. The increase in efficiency of fertilization is involved in supply
of organic nutrients, tillage, soil pH, past weather, the humus content
in the subsoil and grain content to 0.001 mm. The decrease in
efficiency was mainly influenced by the total dose of mineral
nitrogen, although it was divided into multiple doses, the proportion
loamy particles up to 0.01 mm, rainy, or conversely dry weather
during the vegetation. The efficiency of nitrogen was found to be the
smallest on undeveloped soils and the highest on chernozem and
alluvial soils.
Abstract: Computed tomography (CT) dosimetry normally uses
an ionization chamber 100 mm long to estimate the computed
tomography dose index (CTDI), however some reports have already
indicated that small devices could replace the long ion chamber to
improve quality assurance procedures in CT dosimetry. This paper
presents a novel dosimetry system based in a commercial
phototransistor evaluated for CT dosimetry. Three detector
configurations were developed for this system: with a single, two and
four devices. Dose profile measurements were obtained with them
and their angular response were evaluated. The results showed that
the novel dosimetry system with the phototransistor could be an
alternative for CT dosimetry. It allows to obtain the CT dose profile
in details and also to estimate the CTDI in longer length than the
100 mm pencil chamber. The angular response showed that the one
device detector configuration is the most adequate among the three
configurations analyzed in this study.
Abstract: In this paper we develop and analyze the model for
the spread of Leptospirosis by age group in Thailand, between 1997
and 2010 by using mathematical modeling and computer simulation.
Leptospirosis is caused by pathogenic spirochetes of the genus
Leptospira. It is a zoonotic disease of global importance and an
emerging health problem in Thailand. In Thailand, leptospirosis is a
reportable disease, the top three age groups are 23.31% in 35-44
years olds group, 22.76% in 25-34 year olds group, 17.60% in 45-54
year olds group from reported leptospirosis between 1997 and 2010,
with a peak in 35-44 year olds group. Our paper, the Leptosipirosis
transmission by age group in Thailand is studied on the mathematical
model. Some analytical and simulation results are presented.
Abstract: The aim of the study is to determine the effects of
perceived organizational support on organizational identification. In
accordance with this purpose was applied on 131 family physicians in
Konya. The data obtained by means of the survey method were
analyzed. According to the results of correlation analysis, while
positive relationship between perceived organizational support,
organizational identification and supervisor support was revealed.
Also, with the scope of the research, relationships between these
variables and certain demographic variables were detected.
According to difference analysis results of the research, significant
differences between organizational identification and gender variable
were determined. However, significant differences were not
determined between demographic variables and perceived
organizational support.