Abstract: In this paper, the local grid refinement is focused by
using a nested grid technique. The Cartesian grid numerical method is
developed for simulating unsteady, viscous, incompressible flows
with complex immersed boundaries. A finite volume method is used in
conjunction with a two-step fractional-step procedure. The key aspects
that need to be considered in developing such a nested grid solver are
imposition of interface conditions on the inter-block and accurate
discretization of the governing equation in cells that are with the
inter-block as a control surface. A new interpolation procedure is
presented which allows systematic development of a spatial
discretization scheme that preserves the spatial accuracy of the
underlying solver. The present nested grid method has been tested by
two numerical examples to examine its performance in the two
dimensional problems. The numerical examples include flow past a
circular cylinder symmetrically installed in a Channel and flow past
two circular cylinders with different diameters. From the numerical
experiments, the ability of the solver to simulate flows with
complicated immersed boundaries is demonstrated and the nested grid
approach can efficiently speed up the numerical solutions.
Abstract: The aged are faced with increasing risk for falls. The
aged have the easily fragile bones than others. When falls have
occurred, it is important to detect this emergency state because such
events often lead to more serious illness or even death. A
implementation of PDA system, for detection of emergency situation,
was developed using 3-axis accelerometer in this paper as follows.
The signals were acquired from the 3-axis accelerometer, and then
transmitted to the PDA through Bluetooth module. This system can
classify the human activity, and also detect the emergency state like
falls. When the fall occurs, the system generates the alarm on the
PDA. If a subject does not respond to the alarm, the system determines
whether the current situation is an emergency state or not, and then
sends some information to the emergency center in the case of urgent
situation. Three different studies were conducted on 12 experimental
subjects, with results indicating a good accuracy. The first study was
performed to detect the posture change of human daily activity. The
second study was performed to detect the correct direction of fall. The
third study was conducted to check the classification of the daily
physical activity. Each test was lasted at least 1 min. in third study.
The output of acceleration signal was compared and evaluated by
changing a various posture after attaching a 3-axis accelerometer
module on the chest. The newly developed system has some important
features such as portability, convenience and low cost. One of the
main advantages of this system is that it is available at home
healthcare environment. Another important feature lies in low cost to
manufacture device. The implemented system can detect the fall
accurately, so will be widely used in emergency situation.
Abstract: Base on extenics theory, the statistical physical and mechanical properties from laboratory experiments are used to evaluate the bearing capacity of lateritic soil foundation. The properties include water content, bulk density, liquid limit, cohesion, and so on. The matter-element and the dependent function are defined. Then the synthesis dependent degree and the final grade index are calculated. The results show that predicted outcomes can be matched with the in-situ test data, and a evaluate grade associate with bearing capacity can be deduced. The results provide guidance to assess and determine the bearing capacity grade of lateritic soil foundation.
Abstract: The mechanism of abiotic stress tolerance is crucial
for plants to survive in harsh condition and the knowledge of this
mechanism can be use to solve the problem of declining productivity
of plants or crops around the world. However in-depth description is
still unclear and it is argued, in particular that there is a relationship
between high salinity tolerance and the ability to tolerate high light
condition. In this study, Dunaliella salina, which can withstand high
salt was used as a model. Chlorophyll fluorometer for nonphotochemical
quenching (NPQ) measurement and high-performance
liquid chromatography for pigment determination was used. The
results show that NPQ value and the amount of pigment were
increased along with the levels of salinity. However, it establish a
clear relationship between high salt and high light but the further
study to optimized the solutions mentioned above is still required.
Abstract: Plasma Wind Tunnels (PWT) are extensively used for screening and qualification of re-entry Thermel Protection System (TPS) materials. Proper design of a supersonic diffuser for plasma wind tunnel is of importance for achieving good pressurerecovery (thereby reducing vacuum pumping requirement & run time costs) and isolating downstream stream fluctuations from propagating costs) and isolating downstream stream fluctuationnts the details of a rapid design methodology successfully employed for designing supersonic diffuser for high power (several megawatts)plasma wind tunnels and numerical performance analysis of a diffuser configuration designed for one megawatt power rated plasma wind tunnel(enthalpy ~ 30 MJ/kg) using FLUENT 6.3® solver for different diffuser operating sub-atmospheric back-pressures.
Abstract: The paper presents an investigation into the role of virtual reality and web technologies in the field of distance education. Within this frame, special emphasis is given on the building of web-based virtual learning environments so as to successfully fulfill their educational objectives. In particular, basic pedagogical methods are studied, focusing mainly on the efficient preparation, approach and presentation of learning content, and specific designing rules are presented considering the hypermedia, virtual and educational nature of this kind of applications. The paper also aims to highlight the educational benefits arising from the use of virtual reality technology in medicine and study the emerging area of web-based medical simulations. Finally, an innovative virtual reality environment for distance education in medicine is demonstrated. The proposed environment reproduces conditions of the real learning process and enhances learning through a real-time interactive simulator.
Abstract: We report a lithography-free approach to fabricate the
biomimetics, quasi-beehive Si nanostructures (QBSNs), on
Si-substrates. The self-assembled SiGe nanoislands via the strain
induced surface roughening (Asaro-Tiller-Grinfeld instability) during
in-situ annealing play a key role as patterned sacrifice regions for
subsequent reactive ion etching (RIE) process performed for
fabricating quasi-beehive nanostructures on Si-substrates. As the
measurements of field emission, the bare QBSNs show poor field
emission performance, resulted from the existence of the native oxide
layer which forms an insurmountable barrier for electron emission. In
order to dramatically improve the field emission characteristics, the
platinum nanopillars (Pt-NPs) were deposited on QBSNs to form
Pt-NPs/QBSNs heterostructures. The turn-on field of Pt-NPs/QBSNs
is as low as 2.29 V/μm (corresponding current density of 1 μA/cm2),
and the field enhancement factor (β-value) is significantly increased to
6067. More importantly, the uniform and continuous electrons excite
light emission, due to the surrounding filed emitters from
Pt-NPs/QBSNs, can be easily obtained. This approach does not require
an expensive photolithographic process and possesses great potential
for applications.
Abstract: The concentrations of As, Hg, Co, Cr and Cd were
tested for each soil sample, and their spatial patterns were analyzed
by the semivariogram approach of geostatistics and geographical
information system technology. Multivariate statistic approaches
(principal component analysis and cluster analysis) were used to
identify heavy metal sources and their spatial pattern. Principal
component analysis coupled with correlation between heavy metals
showed that primary inputs of As, Hg and Cd were due to
anthropogenic while, Co, and Cr were associated with pedogenic
factors. Ordinary kriging was carried out to map the spatial patters of
heavy metals. The high pollution sources evaluated was related with
usage of urban and industrial wastewater. The results of this study
helpful for risk assessment of environmental pollution for decision
making for industrial adjustment and remedy soil pollution.
Abstract: The purpose of this study is to derive parameters
estimating for the Lyman–Kutcher–Burman (LKB) normal tissue
complication probability (NTCP) model using analysis of scintigraphy
assessments and quality of life (QoL) measurement questionnaires for
the parotid gland (xerostomia). In total, 31 patients with
head-and-neck (HN) cancer were enrolled. Salivary excretion factor
(SEF) and EORTC QLQ-H&N35 questionnaires datasets are used for
the NTCP modeling to describe the incidence of grade 4 xerostomia.
Assuming that n= 1, NTCP fitted parameters are given as TD50= 43.6
Gy, m= 0.18 in SEF analysis, and as TD50= 44.1 Gy, m= 0.11 in QoL
measurements, respectively. SEF and QoL datasets can validate the
Quantitative Analyses of Normal Tissue Effects in the Clinic
(QUANTEC) guidelines well, resulting in NPV-s of 100% for the both
datasets and suggests that the QUANTEC 25/20Gy gland-spared
guidelines are suitable for clinical used for the HN cohort to
effectively avoid xerostomia.
Abstract: Bicycle configuration is not as large as those of motorcycles or automobiles, while it indeed composes a complicated dynamic system. People-s requirements on comfortability, controllability and safety grow higher as the research and development technologies improve. The shock absorber affects the vehicle suspension performances enormously. The absorber takes the vibration energy and releases it at a suitable time, keeping the wheel under a proper contact condition with road surface, maintaining the vehicle chassis stability. Suspension design for mountain bicycles is more difficult than that of city bikes since it encounters dynamic variations on road and loading conditions. Riders need a stiff damper as they exert to tread on the pedals when climbing, while a soft damper when they descend downhill. Various switchable shock absorbers are proposed in markets, however riders have to manually switch them among soft, hard and lock positions. This study proposes a novel design of the bicycle shock absorber, which provides automatic smooth tuning of the damping coefficient, from a predetermined lower bound to theoretically unlimited. An automatic quick releasing valve is involved in this design so that it can release the peak pressure when the suspension fork runs into a square-wave type obstacle and prevent the chassis from damage, avoiding the rider skeleton from injury. This design achieves the automatic tuning process by innovative plunger valve and fluidic passage arrangements without any electronic devices. Theoretical modelling of the damper and spring are established in this study. Design parameters of the valves and fluidic passages are determined. Relations between design parameters and shock absorber performances are discussed in this paper. The analytical results give directions to the shock absorber manufacture.
Abstract: Data of wave height and wind speed were collected
from three existing oil fields in South China Sea – offshore
Peninsular Malaysia, Sarawak and Sabah regions. Extreme values
and other significant data were employed for analysis. The data were
recorded from 1999 until 2008. The results show that offshore
structures are susceptible to unacceptable motions initiated by wind
and waves with worst structural impacts caused by extreme wave
heights. To protect offshore structures from damage, there is a need
to quantify descriptive statistics and determine spectra envelope of
wind speed and wave height, and to ascertain the frequency content
of each spectrum for offshore structures in the South China Sea
shallow waters using measured time series. The results indicate that
the process is nonstationary; it is converted to stationary process by
first differencing the time series. For descriptive statistical analysis,
both wind speed and wave height have significant influence on the
offshore structure during the northeast monsoon with high mean wind
speed of 13.5195 knots ( = 6.3566 knots) and the high mean wave
height of 2.3597 m ( = 0.8690 m). Through observation of the
spectra, there is no clear dominant peak and the peaks fluctuate
randomly. Each wind speed spectrum and wave height spectrum has
its individual identifiable pattern. The wind speed spectrum tends to
grow gradually at the lower frequency range and increasing till it
doubles at the higher frequency range with the mean peak frequency
range of 0.4104 Hz to 0.4721 Hz, while the wave height tends to
grow drastically at the low frequency range, which then fluctuates
and decreases slightly at the high frequency range with the mean
peak frequency range of 0.2911 Hz to 0.3425 Hz.
Abstract: The uses of road map in daily activities are numerous
but it is a hassle to construct and update a road map whenever there
are changes. In Universiti Malaysia Sarawak, research on Automatic
Road Extraction (ARE) was explored to solve the difficulties in
updating road map. The research started with using Satellite Image
(SI), or in short, the ARE-SI project. A Hybrid Simple Colour Space
Segmentation & Edge Detection (Hybrid SCSS-EDGE) algorithm
was developed to extract roads automatically from satellite-taken
images. In order to extract the road network accurately, the satellite
image must be analyzed prior to the extraction process. The
characteristics of these elements are analyzed and consequently the
relationships among them are determined. In this study, the road
regions are extracted based on colour space elements and edge details
of roads. Besides, edge detection method is applied to further filter
out the non-road regions. The extracted road regions are validated by
using a segmentation method. These results are valuable for building
road map and detecting the changes of the existing road database.
The proposed Hybrid Simple Colour Space Segmentation and Edge
Detection (Hybrid SCSS-EDGE) algorithm can perform the tasks
fully automatic, where the user only needs to input a high-resolution
satellite image and wait for the result. Moreover, this system can
work on complex road network and generate the extraction result in
seconds.
Abstract: Natural gas flow contains undesirable solid particles,
liquid condensation, and/or oil droplets and requires reliable
removing equipment to perform filtration. Recent natural gas
processing applications are demanded compactness and reliability of
process equipment. Since conventional means are sophisticated in
design, poor in efficiency, and continue lacking robust, a supersonic
nozzle has been introduced as an alternative means to meet such
demands.
A 3-D Convergent-Divergent Nozzle is simulated using
commercial Code for pressure ratio (NPR) varies from 1.2 to 2. Six
different shapes of nozzle are numerically examined to illustrate the
position of shock-wave as such spot could be considered as a
benchmark of particle separation. Rectangle, triangle, circular,
elliptical, pentagon, and hexagon nozzles are simulated using Fluent
Code with all have same cross-sectional area.
The simple one-dimensional inviscid theory does not describe the
actual features of fluid flow precisely as it ignores the impact of
nozzle configuration on the flow properties. CFD Simulation results,
however, show that nozzle geometry influences the flow structures
including location of shock wave.
The CFD analysis predicts shock appearance when p01/pa>1.2 for
almost all geometry and locates at the lower area ratio (Ae/At).
Simulation results showed that shock wave in Elliptical nozzle has
the farthest distance from the throat among the others at relatively
small NPR. As NPR increases, hexagon would be the farthest. The
numerical result is compared with available experimental data and
has shown good agreement in terms of shock location and flow
structure.
Abstract: SQL injection on web applications is a very popular
kind of attack. There are mechanisms such as intrusion detection
systems in order to detect this attack. These strategies often rely on
techniques implemented at high layers of the application but do not
consider the low level of system calls. The problem of only
considering the high level perspective is that an attacker can
circumvent the detection tools using certain techniques such as URL
encoding. One technique currently used for detecting low-level
attacks on privileged processes is the tracing of system calls. System
calls act as a single gate to the Operating System (OS) kernel; they
allow catching the critical data at an appropriate level of detail. Our
basic assumption is that any type of application, be it a system
service, utility program or Web application, “speaks” the language of
system calls when having a conversation with the OS kernel. At this
level we can see the actual attack while it is happening. We conduct
an experiment in order to demonstrate the suitability of system call
analysis for detecting SQL injection. We are able to detect the attack.
Therefore we conclude that system calls are not only powerful in
detecting low-level attacks but that they also enable us to detect highlevel
attacks such as SQL injection.
Abstract: Mel Frequency Cepstral Coefficient (MFCC) features
are widely used as acoustic features for speech recognition as well
as speaker recognition. In MFCC feature representation, the Mel frequency
scale is used to get a high resolution in low frequency region,
and a low resolution in high frequency region. This kind of processing
is good for obtaining stable phonetic information, but not suitable
for speaker features that are located in high frequency regions. The
speaker individual information, which is non-uniformly distributed
in the high frequencies, is equally important for speaker recognition.
Based on this fact we proposed an admissible wavelet packet based
filter structure for speaker identification. Multiresolution capabilities
of wavelet packet transform are used to derive the new features.
The proposed scheme differs from previous wavelet based works,
mainly in designing the filter structure. Unlike others, the proposed
filter structure does not follow Mel scale. The closed-set speaker
identification experiments performed on the TIMIT database shows
improved identification performance compared to other commonly
used Mel scale based filter structures using wavelets.
Abstract: Intermittent aeration process can be easily applied on
the existing activated sludge system and is highly reliable against the loading changes. It can be operated in a relatively simple way as well.
Since the moving-bed biofilm reactor method processes pollutants by attaching and securing the microorganisms on the media, the process
efficiency can be higher compared to the suspended growth biological
treatment process, and can reduce the return of sludge. In this study,
the existing intermittent aeration process with alternating flow being
applied on the oxidation ditch is applied on the continuous flow stirred tank reactor with advantages from both processes, and we would like
to develop the process to significantly reduce the return of sludge in the clarifier and to secure the reliable quality of treated water by
adding the moving media. Corresponding process has the appropriate
form as an infrastructure based on u- environment in future u- City and
is expected to accelerate the implementation of u-Eco city in conjunction with city based services. The system being conducted in a
laboratory scale has been operated in HRT 8hours except for the final
clarifier and showed the removal efficiency of 97.7 %, 73.1 % and 9.4
% in organic matters, TN and TP, respectively with operating range of
4hour cycle on system SRT 10days. After adding the media, the removal efficiency of phosphorus showed a similar level compared to
that before the addition, but the removal efficiency of nitrogen was
improved by 7~10 %. In addition, the solids which were maintained in
MLSS 1200~1400 at 25 % of media packing were attached all onto the
media, which produced no sludge entering the clarifier. Therefore, the
return of sludge is not needed any longer.
Abstract: Analysis of reciprocating equipment piston rod leads
to nonlinear elastic-plastic deformation analysis of rod with initial
imperfection under axial dynamic load. In this paper a new and
effective model and analytical formulations are presented to evaluate
dynamic deformation and elastic-plastic stresses of reciprocating
machine piston rod. This new method has capability to account for
geometric nonlinearity, elastic-plastic deformation and dynamic
effects. Proposed method can be used for evaluation of piston rod
performance for various reciprocating machines under different
operation situations. Rod load curves and maximum allowable rod
load are calculated with presented method for a refinery type
reciprocating compressor. Useful recommendations and guidelines
for rod load, rod load reversal and rod drop monitoring are also
addressed.
Abstract: This paper deals with rheological behavior of tomato
paste from the view point of time independent properties inclusive of
processing variables such as sample temperature which influence on
rheological properties as well as breaking temperature and
concentration which beside the rheological properties, influence on
the quality of final product. With this aim 10 tomato paste samples at
various concentrations (17-25%) and breaking temperatures (65-
85 C o ) have been produced. The experimental results showed tomato
paste behaves as a non-Newtonian semi-fluid which follows power
law model that consistency coefficient (K) is supposed function of
breaking temperature, concentration and sample temperature with
consideration to superimpose function.
Abstract: In order to implement flexibility as well as survivable
capacities over passive optical network (PON), a new automatic
random fault-recovery mechanism with array-waveguide-grating
based (AWG-based) optical switch (OSW) is presented. Firstly,
wavelength-division-multiplexing and optical code-division
multiple-access (WDM/OCDMA) scheme are configured to meet the
various geographical locations requirement between optical network
unit (ONU) and optical line terminal (OLT). The AWG-base optical
switch is designed and viewed as central star-mesh topology to
prohibit/decrease the duplicated redundant elements such as fiber and
transceiver as well. Hence, by simple monitoring and routing switch
algorithm, random fault-recovery capacity is achieved over
bi-directional (up/downstream) WDM/OCDMA scheme. When error
of distribution fiber (DF) takes place or bit-error-rate (BER) is higher
than 10-9 requirement, the primary/slave AWG-based OSW are
adjusted and controlled dynamically to restore the affected ONU
groups via the other working DFs immediately.
Abstract: Stress Concentration Factors are significant in
machine design as it gives rise to localized stress when any change in
the design of surface or abrupt change in the cross section occurs.
Almost all machine components and structural members contain
some form of geometrical or microstructural discontinuities. These
discontinuities are very dangerous and lead to failure. So, it is very
much essential to analyze the stress concentration factors for critical
applications like Turbine Rotors. In this paper Finite Element
Analysis (FEA) with extremely fine mesh in the vicinity of the
blades of Steam Turbine Rotor is applied to determine stress
concentration factors. A model of Steam Turbine Rotor is shown in
Fig. 1.