Abstract: The Pads have unique values of thermophysical
properties (THP) having important contribution over heat transfer
into the PCB structure.
Materials with high thermal diffusivity (TD) rapidly adjust their
temperature to that of their surroundings, because the HT is quick in
compare to their volumetric heat capacity (VHC).
In the paper is presenting the diffusivity tests (ASTM E1461 flash
method) for PCBs with different core materials. In the experiments,
the multilayer structure of PCBA was taken into consideration, an
equivalent property referring to each of experimental structure be
practically measured.
Concerning to entire structure, the THP emphasize the major
contribution of substrate in establishing of reflow soldering process
(RSP) heat transfer necessities. This conclusion offer practical
solution for heat transfer time constant calculation as function of
thickness and substrate material diffusivity with an acceptable error
estimation.
Abstract: We present an integration approach of a CMOS biosensor into a polymer based microfluidic environment suitable for mass production. It consists of a wafer-level-package for the silicon die and laser bonding process promoted by an intermediate hot melt foil to attach the sensor package to the microfluidic chip, without the need for dispensing of glues or underfiller. A very good condition of the sensing area was obtained after introducing a protection layer during packaging. A microfluidic flow cell was fabricated and shown to withstand pressures up to Δp = 780 kPa without leakage. The employed biosensors were electrically characterized in a dry environment.
Abstract: In today-s economy plant engineering faces many
challenges. For instance the intensifying competition in this business
is leading to cost competition and needs for a shorter time-to-market.
To remain competitive companies need to make their businesses
more profitable by implementing improvement programs such as
standardization projects. But they have difficulties to tap their full
economic potential for various reasons. One of them is non-holistic
planning and implementation of standardization projects. This paper
describes a new conceptual framework - the layer-model. The model
combines and expands existing proven approaches in order to
improve design, implementation and management of standardization
projects. Based on a holistic approach it helps to systematically
analyze the effects of standardization projects on different business
layers and enables companies to better seize the opportunities offered
by standardization.
Abstract: Method of multiple scales is used in the paper in order
to derive an amplitude evolution equation for the most unstable mode
from two-dimensional shallow water equations under the rigid-lid
assumption. It is assumed that shallow mixing layer is slightly curved
in the longitudinal direction and contains small particles. Dynamic
interaction between carrier fluid and particles is neglected. It is
shown that the evolution equation is the complex Ginzburg-Landau
equation. Explicit formulas for the computation of the coefficients of
the equation are obtained.
Abstract: Two species of Physalis, P.angulataL. and P.
peruviana L. were used as models for comparative study to
understand the values of micro-morphological, -anatomical and
architectural characteristics of leaf for taxonomic purposes and
possibly breeding and commercial applications. Both speciespossess
amphistomaticleaves with 1-layer epidermis, 3-4-layer spongy
mesophyll andbicollateral bundle midrib. Palisade parenchyma cells
of P. angulatawere almost twice longer (65-75 μm) than the other
one. Type of stomata was similar as anomocyticbut stomatal
index(SI) at adaxial surface and abaxial surface of P. angulata were
less than of P. peruvianaas 3.57, 4.00 and6.25, 6.66 respectively.
Some leaf architectural characteristics such as leaf shape, order of
venationalsoprovided information of taxonomic significance
Abstract: In the current decade, wireless sensor networks are
emerging as a peculiar multi-disciplinary research area. By this
way, energy efficiency is one of the fundamental research themes
in the design of Medium Access Control (MAC) protocols for
wireless sensor networks. Thus, in order to optimize the energy
consumption in these networks, a variety of MAC protocols are
available in the literature. These schemes were commonly evaluated
under simple network density and a few results are published on
their robustness in realistic network-s size. We, in this paper, provide
an analytical study aiming to highlight the energy waste sources in
wireless sensor networks. Then, we experiment three energy efficient
hybrid CSMA/CA based MAC protocols optimized for wireless
sensor networks: Sensor-MAC (SMAC), Time-out MAC (TMAC)
and Traffic aware Energy Efficient MAC (TEEM). We investigate
these protocols with different network densities in order to discuss
the end-to-end performances of these schemes (i.e. in terms of energy
efficiency, delay and throughput). Through Network Simulator (NS-
2) implementations, we explore the behaviors of these protocols with
respect to the network density. In fact, this study may help the multihops
sensor networks designers to design or select the MAC layer
which matches better their applications aims.
Abstract: Subsonic wind tunnel experiments were conducted to
study the effect of tripped boundary layer on the pressure distribution
in the contraction region of the tunnel. Measurements were
performed by installing trip strip at two different positions in the
concave portion of the contraction. The results show that installation
of the trip strips, have significant effects on both turbulence and
pressure distribution. The reduction in the free stream turbulence and
reduction of the wall static pressure distribution deferred signified
with the location of the trip strip.
Abstract: A numerical study of flow in a horizontally channel
partially filled with a porous screen with non-uniform inlet has been
performed by lattice Boltzmann method (LBM). The flow in porous
layer has been simulated by the Brinkman-Forchheimer model.
Numerical solutions have been obtained for variable porosity models
and the effects of Darcy number and porosity have been studied in
detail. It is found that the flow stabilization is reliant on the Darcy
number. Also the results show that the stabilization of flow field and
heat transfer is depended to Darcy number. Distribution of stream
field becomes more stable by decreasing Darcy number. Results
illustrate that the effect of variable porosity is significant just in the
region of the solid boundary. In addition, difference between constant
and variable porosity models is decreased by decreasing the Darcy
number.
Abstract: Optimum communication and performance in
Wireless Sensor Networks, constitute multi-facet challenges due to
the specific networking characteristics as well as the scarce resource
availability. Furthermore, it is becoming increasingly apparent that
isolated layer based approaches often do not meet the demands posed
by WSNs applications due to omission of critical inter-layer
interactions and dependencies. As a counterpart, cross-layer is
receiving high interest aiming to exploit these interactions and
increase network performance. However, in order to clearly identify
existing dependencies, comprehensive performance studies are
required evaluating the effect of different critical network parameters
on system level performance and behavior.This paper-s main
objective is to address the need for multi-parametric performance
evaluations considering critical network parameters using a well
known network simulator, offering useful and practical conclusions
and guidelines. The results reveal strong dependencies among
considered parameters which can be utilized by and drive future
research efforts, towards designing and implementing highly efficient
protocols and architectures.
Abstract: Although the STL (stereo lithography) file format is
widely used as a de facto industry standard in the rapid prototyping
industry due to its simplicity and ability to tessellation of almost all
surfaces, but there are always some defects and shortcoming in their
usage, which many of them are difficult to correct manually. In
processing the complex models, size of the file and its defects grow
extremely, therefore, correcting STL files become difficult. In this
paper through optimizing the exiting algorithms, size of the files and
memory usage of computers to process them will be reduced. In spite
of type and extent of the errors in STL files, the tail-to-head
searching method and analysis of the nearest distance between tails
and heads techniques were used. As a result STL models sliced
rapidly, and fully closed contours produced effectively and errorless.
Abstract: This paper presents the investigation results of UV
measurement at different level of altitudes and the development of a
new portable instrument for measuring UV. The rapid growth of
industrial sectors in developing countries including Malaysia, brings
not only income to the nation, but also causes pollution in various
forms. Air pollution is one of the significant contributors to global
warming by depleting the Ozone layer, which would reduce the
filtration of UV rays. Long duration of exposure to high to UV rays
has many devastating health effects to mankind directly or indirectly
through destruction of the natural resources. This study aimed to
show correlation between UV and altitudes which indirectly can help
predict Ozone depletion. An instrument had been designed to
measure and monitors the level of UV. The instrument comprises of
two main blocks namely data logger and Graphic User Interface
(GUI). Three sensors were used in the data logger to detect changes
in the temperature, humidity and ultraviolet. The system has
undergone experimental measurement to capture data at two different
conditions; industrial area and high attitude area. The performance of
the instrument showed consistency in the data captured and the
results of the experiment drew a significantly high reading of UV at
high altitudes.
Abstract: This paper presents a new strategy of identification
and classification of pathological voices using the hybrid method
based on wavelet transform and neural networks. After speech
acquisition from a patient, the speech signal is analysed in order to
extract the acoustic parameters such as the pitch, the formants, Jitter,
and shimmer. Obtained results will be compared to those normal and
standard values thanks to a programmable database. Sounds are
collected from normal people and patients, and then classified into
two different categories. Speech data base is consists of several
pathological and normal voices collected from the national hospital
“Rabta-Tunis". Speech processing algorithm is conducted in a
supervised mode for discrimination of normal and pathology voices
and then for classification between neural and vocal pathologies
(Parkinson, Alzheimer, laryngeal, dyslexia...). Several simulation
results will be presented in function of the disease and will be
compared with the clinical diagnosis in order to have an objective
evaluation of the developed tool.
Abstract: I/O workload is a critical and important factor to
analyze I/O pattern and file system performance. However tracing I/O
operations on the fly distributed parallel file system is non-trivial due
to collection overhead and a large volume of data. In this paper, we
design and implement a parallel file system logging method for high
performance computing using shared memory-based multi-layer
scheme. It minimizes the overhead with reduced logging operation
response time and provides efficient post-processing scheme through
shared memory. Separated logging server can collect sequential logs
from multiple clients in a cluster through packet communication.
Implementation and evaluation result shows low overhead and high
scalability of this architecture for high performance parallel logging
analysis.
Abstract: Carbon steel is used in boilers, pressure vessels, heat
exchangers, piping, structural elements and other moderatetemperature
service systems in which good strength and ductility are
desired. ASME Boiler and Pressure Vessel Code, Section II Part A
(2004) provides specifications of ferrous materials for construction of
pressure equipment, covering wide range of mechanical properties
including high strength materials for power plants application.
However, increased level of springback is one of the major problems
in fabricating components of high strength steel using bending.
Presented work discuss the springback simulations for five different
steels (i.e. SA-36, SA-299, SA-515 grade 70, SA-612 and SA-724
grade B) using finite element analysis of air V-bending. Analytical
springback simulations of hypothetical layered materials are
presented. Result shows that; (i) combination of the material property
parameters controls the springback, (ii) layer of the high ductility
steel on the high strength steel greatly suppresses the springback.
Abstract: Performing High Voltage (HV) tasks with a multi craft
work force create a special set of safety circumstances. This paper
aims to present vital information relating to when it is acceptable to
use a single or a two-layer soil structure. Also it discusses the
implication of the high voltage infrastructure on the earth grid and the
safety of this implication under a single or a two-layer soil structure.
A multiple case study is investigated to show the importance of using
the right soil resistivity structure during the earthing system design.
Abstract: Currently, many types of no-reversible compressed
sound source, represented by MP3 (MPEG Audio Layer-3) are
popular in the world and they are widely used to make the music file
size smaller. The sound data created in this way has less information as
compared to pre-compressed data. The objective of this study is by
analyzing EEG to determine if people can recognize such difference as
differences in sound. A measurement system that can measure and
analyze EEG when a subject listens to music were experimentally
developed. And ten subjects were studied with this system. In this
experiment, a WAVE formatted music data and a MP3 compressed
music data that is made from the WAVE formatted data were
prepared. Each subject was made to hear these music sources at the
same volume. From the results of this experiment, clear differences
were confirmed between two wound sources.
Abstract: The paper presents the results of theoretical and
numerical modeling of propagation of shock waves in bubbly liquids
related to nonlinear effects (realistic equation of state, chemical
reactions, two-dimensional effects). On the basis on the Rankine-
Hugoniot equations the problem of determination of parameters of
passing and reflected shock waves in gas-liquid medium for
isothermal, adiabatic and shock compression of the gas component is
solved by using the wide-range equation of state of water in the
analitic form. The phenomenon of shock wave intensification is
investigated in the channel of variable cross section for the
propagation of a shock wave in the liquid filled with bubbles
containing chemically active gases. The results of modeling of the
wave impulse impact on the solid wall covered with bubble layer are
presented.
Abstract: This paper proposes an efficient learning method for the layered neural networks based on the selection of training data and input characteristics of an output layer unit. Comparing to recent neural networks; pulse neural networks, quantum neuro computation, etc, the multilayer network is widely used due to its simple structure. When learning objects are complicated, the problems, such as unsuccessful learning or a significant time required in learning, remain unsolved. Focusing on the input data during the learning stage, we undertook an experiment to identify the data that makes large errors and interferes with the learning process. Our method devides the learning process into several stages. In general, input characteristics to an output layer unit show oscillation during learning process for complicated problems. The multi-stage learning method proposes by the authors for the function approximation problems of classifying learning data in a phased manner, focusing on their learnabilities prior to learning in the multi layered neural network, and demonstrates validity of the multi-stage learning method. Specifically, this paper verifies by computer experiments that both of learning accuracy and learning time are improved of the BP method as a learning rule of the multi-stage learning method. In learning, oscillatory phenomena of a learning curve serve an important role in learning performance. The authors also discuss the occurrence mechanisms of oscillatory phenomena in learning. Furthermore, the authors discuss the reasons that errors of some data remain large value even after learning, observing behaviors during learning.
Abstract: Optical Coherence Tomography (OCT) combined
with the Confocal Microscopy, as a noninvasive method, permits the
determinations of materials defects in the ceramic layers depth. For
this study 256 anterior and posterior metal and integral ceramic fixed
partial dentures were used, made with Empress (Ivoclar), Wollceram
and CAD/CAM (Wieland) technology. For each investigate area 350
slices were obtain and a 3D reconstruction was perform from each
stuck. The Optical Coherent Tomography, as a noninvasive method,
can be used as a control technique in integral ceramic technology,
before placing those fixed partial dentures in the oral cavity. The
purpose of this study is to evaluate the capability of En face Optical
Coherence Tomography (OCT) combined with a fluorescent method
in detection and analysis of possible material defects in metalceramic
and integral ceramic fixed partial dentures. As a conclusion,
it is important to have a non invasive method to investigate fixed
partial prostheses before their insertion in the oral cavity in order to
satisfy the high stress requirements and the esthetic function.
Abstract: Both prognostic and diagnostic modes of a 3D baroclinic
model in hydrodynamic and sediment transport models of
the Princeton Ocean Model (POM) were conducted to separate
prognose and diagnose effects of different hydrodynamic factors on
transport of suspended sediment discharged from the rivers to the
Gulf of Thailand (GoT). Both transport modes of suspended sediment
distribution in the GoT were numerically simulated. It could be
concluded that the suspended sediment discharged from the rivers
around the GoT. Most of sediments in estuaries and coastal areas are
deposited outside the GoT under the condition of wind-driven current,
and very small amount of the sediments of them are transported
faraway. On the basis of wind forcing, sediments from the lower
GoT to the upper GoT are mainly transported south-northwestward
and also continuously moved north-southwestward. An obvious 3D
characteristic of suspended sediment transport is produced in the
wind-driven current residual circulation condition. In this study, the
transport patterns at the third layer are generally consistent with
the typhoon-induced strong currents in two case studies of Typhoon
Linda 1997. The case studies presented the prognostic and diagnostic
modes during 00UTC28OCT1997 to 12UTC06NOV1997 in a short
period with the current condition for pre-operation of the suspended
sediment transport model in estuaries and coastal areas.