Abstract: In this work, thermoelastic damping effect on the hemi- spherical shells is investigated. The material is selected silicon, and heat conduction equation for thermal flow is solved to obtain the temperature profile in which bending approximation with inextensional assumption of the model. Using the temperature profile, eigen-value analysis is performed to get the natural frequencies of hemispherical shells. Effects of mode numbers, radii and radial thicknesses of the model on the natural frequencies are analyzed in detail. Furthermore, the quality factor (Q-factor) is defined, and discussed for the ring and hemispherical shell.
Abstract: In this note, we discuss the convergence behavior of a modified inexact Uzawa algorithm for solving generalized saddle point problems, which is an extension of the result obtained in a recent paper [Z.H. Cao, Fast Uzawa algorithm for generalized saddle point problems, Appl. Numer. Math., 46 (2003) 157-171].
Abstract: The triumph of inductive neuro-stimulation since its rediscovery in the 1980s has been quite spectacular. In lots of branches ranging from clinical applications to basic research this system is absolutely indispensable. Nevertheless, the basic knowledge about the processes underlying the stimulation effect is still very rough and rarely refined in a quantitative way. This seems to be not only an inexcusable blank spot in biophysics and for stimulation prediction, but also a fundamental hindrance for technological progress. The already very sophisticated devices have reached a stage where further optimization requires better strategies than provided by simple linear membrane models of integrate-and-fire style. Addressing this problem for the first time, we suggest in the following text a way for virtual quantitative analysis of a stimulation system. Concomitantly, this ansatz seems to provide a route towards a better understanding by using nonlinear signal processing and taking the nerve as a filter that is adapted for neuronal magnetic stimulation. The model is compact and easy to adjust. The whole setup behaved very robustly during all performed tests. Exemplarily a recent innovative stimulator design known as cTMS is analyzed and dimensioned with this approach in the following. The results show hitherto unforeseen potentials.
Abstract: The principal objective of a water treatment plant is to
produce water that satisfies a set of drinking water quality standards
at a reasonable price to the consumers. The gravel-bed flocculator
provide a simple and inexpensive design for flocculation in small
water treatment plants (less than 5000 m3/day capacity). The packed
bed of gravel provides ideal conditions for the formation of compact
settleable flocs because of continuous recontact provided by the
sinuous flow of water through the interstices formed by the gravel.
The field data which were obtained from the operation of the
water supply treatment unit cover the physical, chemical and
biological water qualities of the raw and settled water as obtained by
the operation of the treatment unit. The experiments were carried out
with the aim of assessing the efficiency of the gravel filter in
removing the turbidity, pathogenic bacteria, from the raw water. The
water treatment plant, which was constructed for the treatment of
river water, was in principle a rapid sand filter.
The results show that the average value of the turbidity level of
the settled water was 4.83 NTU with a standard deviation of turbidity
2.893 NTU. This indicated that the removal efficiency of the
sedimentation tank (gravel filter) was about 67.8 %. for pH values
fluctuated between 7.75 and 8.15, indicating the alkaline nature of
the raw water of the river Shatt Al-Hilla, as expected. Raw water pH
is depressed slightly following alum coagulation. The pH of the
settled water ranged from 7.75 to a maximum of 8.05.
The bacteriological tests which were carried out on the water
samples were: total coliform test, E-coli test, and the plate count test.
In each test the procedure used was as outlined in the Standard
Methods for the Examination of Water and Wastewater (APHA,
AWWA, and WPCF, 1985). The gravel filter exhibit a low
performance in removing bacterial load. The percentage bacterial
removal, which is maximum for total plate count (19%) and
minimum for total coliform (16.82%).
Abstract: Emerging Bio-engineering fields such as Brain
Computer Interfaces, neuroprothesis devices and modeling and
simulation of neural networks have led to increased research activity
in algorithms for the detection, isolation and classification of Action
Potentials (AP) from noisy data trains. Current techniques in the field
of 'unsupervised no-prior knowledge' biosignal processing include
energy operators, wavelet detection and adaptive thresholding. These
tend to bias towards larger AP waveforms, AP may be missed due to
deviations in spike shape and frequency and correlated noise
spectrums can cause false detection. Also, such algorithms tend to
suffer from large computational expense.
A new signal detection technique based upon the ideas of phasespace
diagrams and trajectories is proposed based upon the use of a
delayed copy of the AP to highlight discontinuities relative to
background noise. This idea has been used to create algorithms that
are computationally inexpensive and address the above problems.
Distinct AP have been picked out and manually classified from
real physiological data recorded from a cockroach. To facilitate
testing of the new technique, an Auto Regressive Moving Average
(ARMA) noise model has been constructed bases upon background
noise of the recordings. Along with the AP classification means this
model enables generation of realistic neuronal data sets at arbitrary
signal to noise ratio (SNR).
Abstract: Mobile devices, which are progressively surrounded
in our everyday life, have created a new paradigm where they
interconnect, interact and collaborate with each other. This network
can be used for flexible and secure coordinated sharing. On the other
hand Grid computing provides dependable, consistent, pervasive, and
inexpensive access to high-end computational capabilities. In this
paper, efforts are made to map the concepts of Grid on Ad-Hoc
networks because both exhibit similar kind of characteristics like
Scalability, Dynamism and Heterogeneity. In this context we
propose “Mobile Ad-Hoc Services Grid – MASGRID".
Abstract: Circular tubes have been widely used as structural
members in engineering application. Therefore, its collapse behavior
has been studied for many decades, focusing on its energy absorption
characteristics. In order to predict the collapse behavior of members,
one could rely on the use of finite element codes or experiments.
These tools are helpful and high accuracy but costly and require
extensive running time. Therefore, an approximating model of tubes
collapse mechanism is an alternative for early step of design. This
paper is also aimed to develop a closed-form solution of thin-walled
circular tube subjected to bending. It has extended the Elchalakani et
al.-s model (Int. J. Mech. Sci.2002; 44:1117-1143) to include the
rate of energy dissipation of rolling hinge in the circumferential
direction. The 3-D geometrical collapse mechanism was analyzed by
adding the oblique hinge lines along the longitudinal tube within the
length of plastically deforming zone. The model was based on the
principal of energy rate conservation. Therefore, the rates of internal
energy dissipation were calculated for each hinge lines which are
defined in term of velocity field. Inextensional deformation and
perfect plastic material behavior was assumed in the derivation of
deformation energy rate. The analytical result was compared with
experimental result. The experiment was conducted with a number of
tubes having various D/t ratios. Good agreement between analytical
and experiment was achieved.
Abstract: Thailand is one of the world-s leaders of rice
producers and exporters. Farmers have to increase the rice cultivation
frequency for serving the national increasing of export-s demand. It
leads to an elimination of rice residues by open burning which is the
quickest and costless management method. The open burning of rice
residue is one of the major causes of air pollutants and greenhouse
gas (GHG) emission. Under ASEAN agreement on trans-boundary
haze, Thailand set the master plan to mitigate air pollutant emission
from open burning of agricultural residues. In this master plan,
residues incorporation is promoted as alternative management
method to open burning. However, the assessment of both options in
term of GHG emission in order to investigate their contribution to
long-term global warming is still scarce or inexistent. In this study, a
method on rice residues assessment was first developed in order to
estimate and compare GHG emissions from rice cultivation under
rice residues open burning and the case with incorporation of the
same amount of rice residues, using 2006 IPCC guidelines for
emission estimation and Life Cycle Analysis technique. The
emission from rice cultivation in different preparing area practice
was also discussed.
Abstract: Delay and Disruption Tolerant Networking is part of
the Inter Planetary Internet with primary application being Deep
Space Networks. Its Terrestrial form has interesting research
applications such as Alagappa University Delay Tolerant Water
Monitoring Network which doubles as test beds for improvising its
routing scheme. DTNs depend on node mobility to deliver packets
using a store-carry-and forward paradigm. Throwboxes are small and
inexpensive stationary devices equipped with wireless interfaces and
storage. We propose the use of Throwboxes to enhance the contact
opportunities of the nodes and hence improve the Throughput. The
enhancement is evaluated using Alunivdtnsim, a desktop simulator in
C language and the results are graphically presented.
Abstract: In this article, we propose an Intelligent Medical
Diagnostic System (IMDS) accessible through common
web-based interface, to on-line perform initial screening for
osteoporosis. The fundamental approaches which construct the
proposed system are mainly based on the fuzzy-neural theory,
which can exhibit superiority over other conventional technologies
in many fields. In diagnosis process, users simply answer
a series of directed questions to the system, and then they
will immediately receive a list of results which represents the
risk degrees of osteoporosis. According to clinical testing results,
it is shown that the proposed system can provide the general
public or even health care providers with a convenient, reliable,
inexpensive approach to osteoporosis risk assessment.
Abstract: In the first part of the research work, an electrolyzer (10.16 cm dia and 24.13 cm height) to produce hydrogen and oxygen was constructed for single slice O2/H2 fuel cell using cation exchange membrane. The electrolyzer performance was tested with 23% NaOH, 30% NaOH, 30% KOH and 35% KOH electrolyte solution with current input 4 amp and 2.84 V from the rectifier. Rates of volume of hydrogen produced were 0.159 cm3/sec, 0.155 cm3/sec, 0.169 cm3/sec and 0.163 cm3/sec respectively from 23% NaOH, 30% NaOH, 30% KOH and 35% KOH solution. Rates of volume of oxygen produced were 0.212 cm3/sec, 0.201 cm3/sec, 0.227 cm3/sec and 0.219 cm3/sec respectively from 23% NaOH, 30% NaOH, 30% KOH and 35% KOH solution (1.5 L). In spite of being tested the increased concentration of electrolyte solution, the gas rate does not change significantly. Therefore, inexpensive 23% NaOH electrolyte solution was chosen to use as the electrolyte in the electrolyzer. In the second part of the research work, graphite serpentine flow plates, fiberglass end plates, stainless steel screen electrodes, silicone rubbers were made to assemble the single slice O2/H2 polymer electrolyte membrane fuel cell (PEMFC).