Abstract: In this study, an optimization of supersonic air-to-air ejector is carried out by a recently developed single-objective genetic algorithm based on adaption of sequence of individuals. Adaptation of sequence is based on Shape-based distance of individuals and embedded micro-genetic algorithm. The optimal sequence found defines the succession of CFD-aimed objective calculation within each generation of regular micro-genetic algorithm. A spring-based deformation mutates the computational grid starting the initial individualvia adapted population in the optimized sequence. Selection of a generation initial individual is knowledge-based. A direct comparison of the newly defined and standard micro-genetic algorithm is carried out for supersonic air-to-air ejector. The only objective is to minimize the loose of total stagnation pressure in the ejector. The result is that sequence-adopted micro-genetic algorithm can provide comparative results to standard algorithm but in significantly lower number of overall CFD iteration steps.
Abstract: The nonlinear damping behavior is usually ignored in
the design of a miniature moving-coil loudspeaker. But when the
loudspeaker operated in air, the damping parameter varies with the
voice-coil displacement corresponding due to viscous air flow. The
present paper presents an identification model as inverse problem to
identify the nonlinear damping parameter in the lumped parameter
model for the loudspeaker. Theoretical results for the nonlinear
damping are verified by using laser displacement measurement
scanner. These results indicate that the damping parameter has the
greatly different nonlinearity between in air and vacuum. It is believed
that the results of the present work can be applied in diagnosis and
sound quality improvement of a miniature loudspeaker.
Abstract: This study was set to determine the antimicrobial
activities of brine salting, chlorinated solution, and oil frying
treatments on enteric bacteria and fungi in Rastrineobola argentea
fish from fish landing beaches within L. Victoria basin of western
Kenya. Statistical differences in effectiveness of the different
treatment methods was determined by single factor ANOVA, and
paired two-tail t-Test was performed to compare the differences in
moisture contents before and after storage. Oil fried fish recorded the
lowest microbial loads, sodium chloride at 10% concentration was
the second most effective and chlorinated solution even at 150ppm
was the least effective against the bacteria and fungi in fish. Moisture
contents of the control and treated fish were significantly lower after
storage. These results show that oil frying of fish should be adopted
for processing and preserving Rastrineobola argentea which is the
most abundant and affordable fish species from Lake Victoria.
Abstract: The forest fires in Thailand are annual occurrence which is the cause of air pollutions. This study intended to estimate the emission from forest fire during 2005-2009 using MODerateresolution Imaging Spectro-radiometer (MODIS) sensor aboard the Terra and Aqua satellites, experimental data, and statistical data. The forest fire emission is estimated using equation established by Seiler and Crutzen in 1982. The spatial and temporal variation of forest fire emission is analyzed and displayed in the form of grid density map. From the satellite data analysis suggested between 2005 and 2009, the number of fire hotspots occurred 86,877 fire hotspots with a significant highest (more than 80% of fire hotspots) in the deciduous forest. The peak period of the forest fire is in January to May. The estimation on the emissions from forest fires during 2005 to 2009 indicated that the amount of CO, CO2, CH4, and N2O was about 3,133,845 tons, 47,610.337 tons, 204,905 tons, and 6,027 tons, respectively, or about 6,171,264 tons of CO2eq. They also emitted 256,132 tons of PM10. The year 2007 was found to be the year when the emissions were the largest. Annually, March is the period that has the maximum amount of forest fire emissions. The areas with high density of forest fire emission were the forests situated in the northern, the western, and the upper northeastern parts of the country.
Abstract: In this paper, the data correction algorithm is suggested
when the environmental air temperature varies. To correct the infrared
data in this paper, the initial temperature or the initial infrared image
data is used so that a target source system may not be necessary. The
temperature data obtained from infrared detector show nonlinear
property depending on the surface temperature. In order to handle this
nonlinear property, Taylor series approach is adopted. It is shown that
the proposed algorithm can reduce the influence of environmental
temperature on the components in the board. The main advantage of
this algorithm is to use only the initial temperature of the components
on the board rather than using other reference device such as black
body sources in order to get reference temperatures.
Abstract: Network-Centric Air Defense Missile Systems
(NCADMS) represents the superior development of the air defense
missile systems and has been regarded as one of the major research
issues in military domain at present. Due to lack of knowledge and
experience on NCADMS, modeling and simulation becomes an effective
approach to perform operational analysis, compared with
those equation based ones. However, the complex dynamic interactions
among entities and flexible architectures of NCADMS put forward
new requirements and challenges to the simulation framework
and models. ABS (Agent-Based Simulations) explicitly addresses
modeling behaviors of heterogeneous individuals. Agents have capability
to sense and understand things, make decisions, and act on the
environment. They can also cooperate with others dynamically to
perform the tasks assigned to them. ABS proves an effective approach
to explore the new operational characteristics emerging in
NCADMS. In this paper, based on the analysis of network-centric
architecture and new cooperative engagement strategies for
NCADMS, an agent-based simulation framework by expanding the
simulation framework in the so-called System Effectiveness Analysis
Simulation (SEAS) was designed. The simulation framework specifies
components, relationships and interactions between them, the
structure and behavior rules of an agent in NCADMS. Based on scenario
simulations, information and decision superiority and operational
advantages in NCADMS were analyzed; meanwhile some
suggestions were provided for its future development.
Abstract: Pollution emission levels of aircraft engines are a
nowadays high concern. Any technological advance that could reduce
emission levels is always welcome. In what concerns aircraft engines,
a possible solution for this problem could be the use of regenerators
and intercoolers. These components might reduce the specific fuel
consumption, increase efficiency and specific thrust and consequently
reduce the pollution levels of the engine. This is not a novel solution.
These heat exchangers are already is use in stationary engines. For
aircraft engines, the extra weight of the needed hardware could
overcome the fuel saved. This work compares a conventional engine
with configurations that use intercoolers and regenerators.
Abstract: Fuzzy logic system (FLS) is used in this study to
predict the tractive performance in terms of traction force, and
motion resistance for an intelligent air cushion track vehicle while it
operates in the swamp peat. The system is effective to control the
intelligent air –cushion system with measuring the vehicle traction
force (TF), motion resistance (MR), cushion clearance height (CH)
and cushion pressure (CP). Ultrasonic displacement sensor, pull-in
solenoid electromagnetic switch, pressure control sensor, micro
controller, and battery pH sensor are incorporated with the Fuzzy
logic system to investigate experimentally the TF, MR, CH, and CP.
In this study, a comparison for tractive performance of an intelligent
air cushion track vehicle has been performed with the results obtained
from the predicted values of FLS and experimental actual values. The
mean relative error of actual and predicted values from the FLS
model on traction force, and total motion resistance are found as 5.58
%, and 6.78 % respectively. For all parameters, the relative error of
predicted values are found to be less than the acceptable limits. The
goodness of fit of the prediction values from the FLS model on TF,
and MR are found as 0.90, and 0.98 respectively.
Abstract: The elimination of ranitidine (a pharmaceutical
compound) has been carried out in the presence of UV-C radiation.
After some preliminary experiments, it has been experienced the no
influence of the gas nature (air or oxygen) bubbled in photolytic
experiments. From simple photolysis experiments the quantum yield
of this compound has been determined. Two photolytic
approximation has been used, the linear source emission in parallel
planes and the point source emission in spherical planes. The
quantum yield obtained was in the proximity of 0.05 mol Einstein-1
regardless of the method used. Addition of free radical promoters
(hydrogen peroxide) increases the ranitidine removal rate while the
use of photocatalysts (TiO2) negatively affects the process.
Abstract: A frequency grouping approach for multi-channel
instantaneous blind source separation (I-BSS) of convolutive
mixtures is proposed for a lower net residual inter-symbol
interference (ISI) and inter-channel interference (ICI) than the
conventional short-time Fourier transform (STFT) approach. Starting
in the time domain, STFTs are taken with overlapping windows to
convert the convolutive mixing problem into frequency domain
instantaneous mixing. Mixture samples at the same frequency but
from different STFT windows are grouped together forming unique
frequency groups.
The individual frequency group vectors are input to the I-BSS
algorithm of choice, from which the output samples are dispersed
back to their respective STFT windows. After applying the inverse
STFT, the resulting time domain signals are used to construct the
complete source estimates via the weighted overlap-add method
(WOLA). The proposed algorithm is tested for source deconvolution
given two mixtures, and simulated along with the STFT approach to
illustrate its superiority for fairly motionless sources.
Abstract: Location-based services (LBS) exploit the known
location of a user to provide services dependent on their geographic
context and personalized needs [1].
The development and arrival of broadband mobile data networks
supported with mobile terminals equipped with new location
technologies like GPS have finally created opportunities for
implementation of LBS applications. But, from the other side,
collecting location information data in general raises privacy
concerns.
This paper presents results from two surveys of LBS acceptance in
Croatia. The first survey was administered on 181 students, and the
second extended survey involved pattern of 180 Croatian citizens.
We developed questionnaire which consists of descriptions of 15
different applications with scale which measures perceptions and
attitudes of users towards these applications.
We report the results to identify potential commercial applications
for LBS in B2C segment. Our findings suggest that some types of
applications like emergency&safety services and navigation have
significantly higher rate of acceptance than other types.
Abstract: Heavy rainfall greatly affects the aerodynamic performance of the aircraft. There are many accidents of aircraft caused by aerodynamic efficiency degradation by heavy rain.
In this Paper we have studied the heavy rain effects on the aerodynamic efficiency of cambered NACA 64-210 and symmetric
NACA 0012 airfoils. Our results show significant increase in drag and decrease in lift. We used preprocessing software gridgen for creation of geometry and mesh, used fluent as solver and techplot as postprocessor. Discrete phase modeling called DPM is used to model the rain particles using two phase flow approach. The rain particles are assumed to be inert.
Both airfoils showed significant decrease in lift and increase in drag in simulated rain environment. The most significant difference between these two airfoils was the NACA 64-210 more sensitivity than NACA 0012 to liquid water content (LWC). We believe that the results showed in this paper will be useful for the designer of the commercial aircrafts and UAVs, and will be helpful for training of the pilots to control the airplanes in heavy rain.
Abstract: Nano MgO has been synthesized by hydration and
dehydration method by modifies the commercial MgO. The prepared
MgO had been investigated as a heterogeneous base catalyst for
transesterification process for biodiesel production using palm oil.
TGA, FT-IR and XRD results obtained from this study lie each other
and proved in the formation of nano MgO from decomposition of
Mg(OH)2. This study proved that the prepared nano MgO was a
better base transesterification catalyst compared to commercial MgO.
The nano MgO calcined at 600ºC had gives the highest conversion of
51.3% of palm oil to biodiesel.
Abstract: In a state-of-the-art industrial production line of
photovoltaic products the handling and automation processes are of
particular importance and implication. While processing a fully
functional crystalline solar cell an as-cut photovoltaic wafer is subject
to numerous repeated handling steps. With respect to stronger
requirements in productivity and decreasing rejections due to defects
the mechanical stress on the thin wafers has to be reduced to a
minimum as the fragility increases by decreasing wafer thicknesses.
In relation to the increasing wafer fragility, researches at the
Fraunhofer Institutes IPA and CSP showed a negative correlation
between multiple handling processes and the wafer integrity. Recent
work therefore focused on the analysis and optimization of the dry
wafer stack separation process with compressed air. The achievement
of a wafer sensitive process capability and a high production
throughput rate is the basic motivation in this research.
Abstract: In aerospace applications, interactions of airflow with
aircraft structures can result in undesirable structural deformations.
This structural deformation in turn, can be predicted if the natural
modes of the structure are known. This can be achieved through
conventional modal testing that requires a known excitation force in
order to extract these dynamic properties. This technique can be
experimentally complex because of the need for artificial excitation
and it is also does not represent actual operational condition. The
current work presents part of research work that address the practical
implementation of operational modal analysis (OMA) applied to a
cantilevered hybrid composite plate employing single contactless
sensing system via laser vibrometer. OMA technique extracts the
modal parameters based only on the measurements of the dynamic
response. The OMA results were verified with impact hammer modal
testing and good agreement was obtained.
Abstract: The objective of this study is to investigate fire
behaviors, experimentally and numerically, in a scaled version of an
underground station. The effect of ventilation velocity on the fire is
examined. Fire experiments are simulated by burning 10 ml
isopropyl alcohol fuel in a fire pool with dimensions 5cm x 10cm x 4
mm at the center of 1/100 scaled underground station model. A
commercial CFD program FLUENT was used in numerical
simulations. For air flow simulations, k-ω SST turbulence model and
for combustion simulation, non-premixed combustion model are
used. This study showed that, the ventilation velocity is increased
from 1 m/s to 3 m/s the maximum temperature in the station is found
to be less for ventilation velocity of 1 m/s. The reason for these
experimental result lies on the relative dominance of oxygen supply
effect on cooling effect. Without piston effect, maximum temperature
occurs above the fuel pool. However, when the ventilation velocity
increased the flame was tilted in the direction of ventilation and the
location of maximum temperature moves along the flow direction.
The velocities measured experimentally in the station at different
locations are well matched by the CFD simulation results. The
prediction of general flow pattern is satisfactory with the smoke
visualization tests. The backlayering in velocity is well predicted by
CFD simulation. However, all over the station, the CFD simulations
predicted higher temperatures compared to experimental
measurements.
Abstract: Low temperature (LT) is one of the most abiotic
stresses causing loss of yield in wheat (T. aestivum). Four major
genes in wheat (Triticum aestivum L.) with the dominant alleles
designated Vrn–A1,Vrn–B1,Vrn–D1 and Vrn4, are known to have
large effects on the vernalization response, but the effects on cold
hardiness are ambiguous. Poor cold tolerance has restricted winter
wheat production in regions of high winter stress [9]. It was known
that nearly all wheat chromosomes [5] or at least 10 chromosomes of
21 chromosome pairs are important in winter hardiness [15]. The
objective of present study was to clarify the role of each chromosome
in cold tolerance. With this purpose we used 20 isogenic lines of
wheat. In each one of these isogenic lines only a chromosome from
‘Bezostaya’ variety (a winter habit cultivar) was substituted to
‘Capple desprez’ variety. The plant materials were planted in
controlled conditions with 20º C and 16 h day length in moderately
cold areas of Iran at Karaj Agricultural Research Station in 2006-07
and the acclimation period was completed for about 4 weeks in a
cold room with 4º C. The cold hardiness of these isogenic lines was
measured by LT50 (the temperature in which 50% of the plants are
killed by freezing stress).The experimental design was completely
randomized block design (RCBD)with three replicates. The results
showed that chromosome 5A had a major effect on freezing
tolerance, and then chromosomes 1A and 4A had less effect on this
trait. Further studies are essential to understanding the importance of
each chromosome in controlling cold hardiness in wheat.
Abstract: This research aimed to study correlation between
work satisfaction and organization core value of officers in
Waterworks Authority, Bangkean Branch. Sample group of the study
was 112 officers who worked in the Waterworks Authority,
Bangkean Branch. Questionnaires were employed as a research tools,
while, Percentage, Mean, Standard Deviation, T-test, One-way
ANOVA, and Pearson Product Moment Correlation were claimed as
statistics used in this study. Researcher found that overall and
individual aspects of work satisfaction namely, work characteristic,
work progress, and colleagues significantly correlated with
organization core value in aspect of perception in choice of work at
0.5, 0.01, and 0.01 respectively. Also, such aspects were compatible
with income at .05 which indicated the low level of correlation, mid
low correlation respectively at the same direction, same direction,
opposite direction, and same direction, correspondingly.
Abstract: The aims of this study were to compare the
differences of being good membership behavior among faculties and
staffs of Suan Sunandha Rajabhat University with different sex, age,
income, education, marital status, and working period, and
investigate the relationships between organizational commitment and
being good membership behavior. The research methodology
employed a questionnaire as a quantitative method. The respondents
were 305 faculties and staffs of Suan Sunandha Rajabhat University.
This research used Percentage, Mean, Standard Deviation, t-test,
One-Way ANOVA Analysis of Variance, and Pearson’s Product
Moment Correlation Coefficient in data analysis. The results showed
that organizational commitment among faculties and staffs of Suan
Sunandha Rajabhat University was at a high level. In addition,
differences in sex, age, income, education, marital status, and
working period revealed differences in being good membership
behavior. The results also indicated that organizational commitment
was significantly related to being good membership behavior.
Abstract: Laser Metal Deposition (LMD) is an additive manufacturing process with capabilities that include: producing new
part directly from 3 Dimensional Computer Aided Design (3D CAD)
model, building new part on the existing old component and repairing an existing high valued component parts that would have
been discarded in the past. With all these capabilities and its advantages over other additive manufacturing techniques, the
underlying physics of the LMD process is yet to be fully understood probably because of high interaction between the processing
parameters and studying many parameters at the same time makes it
further complex to understand. In this study, the effect of laser power
and powder flow rate on physical properties (deposition height and
deposition width), metallurgical property (microstructure) and
mechanical (microhardness) properties on laser deposited most
widely used aerospace alloy are studied. Also, because the Ti6Al4V
is very expensive, and LMD is capable of reducing buy-to-fly ratio
of aerospace parts, the material utilization efficiency is also studied.
Four sets of experiments were performed and repeated to establish repeatability using laser power of 1.8 kW and 3.0 kW, powder flow
rate of 2.88 g/min and 5.67 g/min, and keeping the gas flow rate and
scanning speed constant at 2 l/min and 0.005 m/s respectively. The
deposition height / width are found to increase with increase in laser
power and increase in powder flow rate. The material utilization is favoured by higher power while higher powder flow rate reduces
material utilization. The results are presented and fully discussed.