Abstract: The objective of the paper is a numerical study of heat
transfer between perforated metal plates and the surrounding air
flows. Different perforation structures can nowadays be found in
various industrial products. Besides improving the mechanical
properties, the perforations can intensify the heat transfer as well. The
heat transfer coefficient depends on a wide range of parameters such
as type of perforation, size, shape, flow properties of the surrounding
air etc. The paper was focused on three different perforation
structures which have been investigated from the point of the view of
the production in the previous studies. To determine the heat
coefficients and the Nusselt numbers, the numerical simulation
approach was adopted. The calculations were performed using the
OpenFOAM software. The three-dimensional, unstable, turbulent and
incompressible air flow around the perforated surface metal plate was
considered.
Abstract: Recent investigations have demonstrated the global
sea level rise due to climate change impacts. In this study, climate
changes study the effects of increasing water level in the strait of
Hormuz. The probable changes of sea level rise should be
investigated to employ the adaption strategies. The climatic output
data of a GCM (General Circulation Model) named CGCM3 under
climate change scenario of A1b and A2 were used. Among different
variables simulated by this model, those of maximum correlation
with sea level changes in the study region and least redundancy
among themselves were selected for sea level rise prediction by using
stepwise regression. One of models (Discrete Wavelet artificial
Neural Network) was developed to explore the relationship between
climatic variables and sea level changes. In these models, wavelet
was used to disaggregate the time series of input and output data into
different components and then ANN was used to relate the
disaggregated components of predictors and input parameters to each
other. The results showed in the Shahid Rajae Station for scenario
A1B sea level rise is among 64 to 75 cm and for the A2 Scenario sea
level rise is among 90 t0 105 cm. Furthermore, the result showed a
significant increase of sea level at the study region under climate
change impacts, which should be incorporated in coastal areas
management.
Abstract: In this paper, a novel fuzzy approach is developed
while solving the Dynamic Routing and Wavelength Assignment
(DRWA) problem in optical networks with Wavelength Division
Multiplexing (WDM). In this work, the effect of nonlinear and linear
impairments such as Four Wave Mixing (FWM) and amplifier
spontaneous emission (ASE) noise are incorporated respectively. The
novel algorithm incorporates fuzzy logic controller (FLC) to reduce
the effect of FWM noise and ASE noise on a requested lightpath
referred in this work as FWM aware fuzzy dynamic routing and
wavelength assignment algorithm. The FWM crosstalk products and
the static FWM noise power per link are pre computed in order to
reduce the set up time of a requested lightpath, and stored in an
offline database. These are retrieved during the setting up of a
lightpath and evaluated online taking the dynamic parameters like
cost of the links into consideration.
Abstract: In this study, a general approach to the reliability
based limit analysis of laterally loaded piles is presented. In
engineering practice the uncertainties play a very important role. The
aim of this study is to evaluate the lateral load capacity of free-head
and fixed-head long pile when plastic limit analysis is considered. In
addition to the plastic limit analysis to control the plastic behaviour
of the structure, uncertain bound on the complementary strain energy
of the residual forces is also applied. This bound has significant effect
for the load parameter. The solution to reliability-based problems is
obtained by a computer program which is governed by the reliability
index calculation.
Abstract: Underwater acoustic networks have attracted great
attention in the last few years because of its numerous applications.
High data rate can be achieved by efficiently modeling the physical
layer in the network protocol stack. In Acoustic medium,
propagation speed of the acoustic waves is dependent on many
parameters such as temperature, salinity, density, and depth.
Acoustic propagation speed cannot be modeled using standard
empirical formulas such as Urick and Thorp descriptions. In this
paper, we have modeled the acoustic channel using real time data of
temperature, salinity, and speed of Bay of Bengal (Indian Coastal
Region). We have modeled the acoustic channel by using Mackenzie
speed equation and real time data obtained from National Institute of
Oceanography and Technology. It is found that acoustic propagation
speed varies between 1503 m/s to 1544 m/s as temperature and
depth differs. The simulation results show that temperature, salinity,
depth plays major role in acoustic propagation and data rate
increases with appropriate data sets substituted in the simulated
model.
Abstract: Presently various computational techniques are used
in modeling and analyzing environmental engineering data. In the
present study, an intra-comparison of polynomial and radial basis
kernel functions based on Support Vector Regression and, in turn, an
inter-comparison with Multi Linear Regression has been attempted in
modeling mass transfer capacity of vertical (θ = 90O) and inclined (θ
multiple plunging jets (varying from 1 to 16 numbers). The data set
used in this study consists of four input parameters with a total of
eighty eight cases, forty four each for vertical and inclined multiple
plunging jets. For testing, tenfold cross validation was used.
Correlation coefficient values of 0.971 and 0.981 along with
corresponding root mean square error values of 0.0025 and 0.0020
were achieved by using polynomial and radial basis kernel functions
based Support Vector Regression respectively. An intra-comparison
suggests improved performance by radial basis function in
comparison to polynomial kernel based Support Vector Regression.
Further, an inter-comparison with Multi Linear Regression
(correlation coefficient = 0.973 and root mean square error = 0.0024)
reveals that radial basis kernel functions based Support Vector
Regression performs better in modeling and estimating mass transfer
by multiple plunging jets.
Abstract: This paper presents a comparative analysis of
continuously stirred tank reactor (CSTR) control based on adaptive
control and optimal tuning of PID control based on particle swarm
optimization. In the design of adaptive control, Model reference
adaptive control (MRAC) scheme is used, in which the adaptation
law have been developed by MIT rule & Lyapunov’s rule. In PSO
control parameters of PID controller is tuned by using the concept of
particle swarm optimization to get optimized operating point for
minimum integral square error (ISE) condition. The results show the
adjustment of PID parameters converting into the optimal operating
point and the good control response can be obtained by the PSO
technique.
Abstract: Annihilations, phase shifts, scattering lengths and
elastic cross sections of low energy positrons scattering from
magnesium atoms were studied using the least-squares variational
method (LSVM). The possibility of positron binding to the
magnesium atoms is investigated. A trial wave function is suggested
to represent e+-Mg elastic scattering and scattering parameters were
derived to estimate the binding energy and annihilation rates. The
trial function is taken to depend on several adjustable parameters, and
is improved iteratively by increasing the number of terms. The
present results have the same behavior as reported semi-empirical,
theoretical and experimental results. Especially, the estimated
positive scattering length supports the possibility of positronmagnesium
bound state system that was confirmed in previous
experimental and theoretical work.
Abstract: Adequate and reliable estimates of aquifer parameters
are of utmost importance for proper management of vital
groundwater resources. At present scenario, the ground water is
polluted because of industrial waste disposed over the land and the
contaminants are transported in the aquifer from one area to another
area, which is depending on the characteristics of the aquifer and
contaminants. To know the contaminant transport, the accurate
estimation of aquifer properties is highly needed. Conventionally,
these properties are estimated through pumping tests carried out on
water wells. The occurrence and movement of ground water in the
aquifer are characteristically defined by the aquifer parameters. The
pumping (aquifer) test is the standard technique for estimating
various hydraulic properties of aquifer systems, viz., transmissivity
(T), hydraulic conductivity (K), storage coefficient (S) etc., for which
the graphical method is widely used. The study area for conducting
pumping test is Pydibheemavaram Industrial area near the coastal
belt of Srikulam, AP, India. The main objective of the present work is
to estimate the aquifer properties for developing contaminant
transport model for the study area.
Abstract: Graphene, a single-atom sheet, has been considered as
the most promising material for making future nanoelectromechanical
systems as well as purely electrical switching with graphene
transistors. Graphene-based devices have advantages in scaled-up
device fabrication due to the recent progress in large area graphene
growth and lithographic patterning of graphene nanostructures. Here
we investigated its mechanical responses of circular graphene
nanoflake under the nanoindentation using classical molecular
dynamics simulations. A correlation between the load and the
indentation depth was constructed. The nanoindented force in this
work was applied to the center point of the circular graphene nanoflake
and then, the resonance frequency could be tuned by a nanoindented
depth. We found the hardening or the softening of the graphene
nanoflake during its nanoindented-deflections, and such properties
were recognized by the shift of the resonance frequency. The
calculated mechanical parameters in the force-vs-deflection plot were
in good agreement with previous experimental and theoretical works.
This proposed schematics can detect the pressure via the deflection
change or/and the resonance frequency shift, and also have great
potential for versatile applications in nanoelectromechanical systems.
Abstract: To study the dynamic mechanics response of asphalt
pavement under the temperature load and vehicle loading, asphalt
pavement was regarded as multilayered elastic half-space system, and
theory analysis was conducted by regarding dynamic modulus of
asphalt mixture as the parameter. Firstly, based on the dynamic
modulus test of asphalt mixture, function relationship between the
dynamic modulus of representative asphalt mixture and temperature
was obtained. In addition, the analytical solution for thermal stress in
single layer was derived by using Laplace integral transformation and
Hankel integral transformation respectively by using thermal
equations of equilibrium. The analytical solution of calculation model
of thermal stress in asphalt pavement was derived by transfer matrix
of thermal stress in multilayer elastic system. Finally, the variation of
thermal stress in pavement structure was analyzed. The result shows
that there is obvious difference between the thermal stress based on
dynamic modulus and the solution based on static modulus. So the
dynamic change of parameter in asphalt mixture should be taken into
consideration when theoretical analysis is taken out.
Abstract: Maintaining factory default battery endurance rate
over time in supporting huge amount of running applications on
energy-restricted mobile devices has created a new challenge for
mobile applications developer. While delivering customers’
unlimited expectations, developers are barely aware of efficient use
of energy from the application itself. Thus, developers need a set of
valid energy consumption indicators in assisting them to develop
energy saving applications. In this paper, we present a few software
product metrics that can be used as an indicator to measure energy
consumption of Android-based mobile applications in the early of
design stage. In particular, Trepn Profiler (Power profiling tool for
Qualcomm processor) has used to collect the data of mobile
application power consumption, and then analyzed for the 23
software metrics in this preliminary study. The results show that
McCabe cyclomatic complexity, number of parameters, nested block
depth, number of methods, weighted methods per class, number of
classes, total lines of code and method lines have direct relationship
with power consumption of mobile application.
Abstract: Exact solution of an unsteady MHD flow of elasticoviscous
fluid through a porous media in a tube of elliptic cross
section under the influence of magnetic field and constant pressure
gradient has been obtained in this paper. Initially, the flow is
generated by a constant pressure gradient. After attaining the steady
state, the pressure gradient is suddenly withdrawn and the resulting
fluid motion in a tube of elliptical cross section by taking into
account of the porosity factor and magnetic parameter of the
bounding surface is investigated. The problem is solved in two-stages
the first stage is a steady motion in tube under the influence of a
constant pressure gradient, the second stage concern with an unsteady
motion. The problem is solved employing separation of variables
technique. The results are expressed in terms of a non-dimensional
porosity parameter, magnetic parameter and elastico-viscosity
parameter, which depends on the Non-Newtonian coefficient. The
flow parameters are found to be identical with that of Newtonian case
as elastic-viscosity parameter, magnetic parameter tends to zero, and
porosity tends to infinity. The numerical results were simulated in
MATLAB software to analyze the effect of Elastico-viscous
parameter, porosity parameter, and magnetic parameter on velocity
profile. Boundary conditions were satisfied. It is seen that the effect
of elastico-viscosity parameter, porosity parameter and magnetic
parameter of the bounding surface has significant effect on the
velocity parameter.
Abstract: In this paper, a comparative performance analysis of
mostly used four nonlinearity cancellation techniques used to realize
the passive resistor by MOS transistors, is presented. The comparison
is done by using an integrator circuit which is employing sequentially
Op-amp, OTRA and ICCII as active element. All of the circuits are
implemented by MOS-C realization and simulated by PSPICE
program using 0.35μm process TSMC MOSIS model parameters.
With MOS-C realization, the circuits became electronically tunable
and fully integrable which is very important in IC design. The output
waveforms, frequency responses, THD analysis results and features
of the nonlinearity cancellation techniques are also given.
Abstract: People, throughout the history, have made estimates
and inferences about the future by using their past experiences.
Developing information technologies and the improvements in the
database management systems make it possible to extract useful
information from knowledge in hand for the strategic decisions.
Therefore, different methods have been developed. Data mining by
association rules learning is one of such methods. Apriori algorithm,
one of the well-known association rules learning algorithms, is not
commonly used in spatio-temporal data sets. However, it is possible
to embed time and space features into the data sets and make Apriori
algorithm a suitable data mining technique for learning spatiotemporal
association rules. Lake Van, the largest lake of Turkey, is a
closed basin. This feature causes the volume of the lake to increase or
decrease as a result of change in water amount it holds. In this study,
evaporation, humidity, lake altitude, amount of rainfall and
temperature parameters recorded in Lake Van region throughout the
years are used by the Apriori algorithm and a spatio-temporal data
mining application is developed to identify overflows and newlyformed
soil regions (underflows) occurring in the coastal parts of
Lake Van. Identifying possible reasons of overflows and underflows
may be used to alert the experts to take precautions and make the
necessary investments.
Abstract: The critical concern of satellite operations is to ensure
the health and safety of satellites. The worst case in this perspective
is probably the loss of a mission, but the more common interruption
of satellite functionality can result in compromised mission
objectives. All the data acquiring from the spacecraft are known as
Telemetry (TM), which contains the wealth information related to the
health of all its subsystems. Each single item of information is
contained in a telemetry parameter, which represents a time-variant
property (i.e. a status or a measurement) to be checked. As a
consequence, there is a continuous improvement of TM monitoring
systems to reduce the time required to respond to changes in a
satellite's state of health. A fast conception of the current state of the
satellite is thus very important to respond to occurring failures.
Statistical multivariate latent techniques are one of the vital learning
tools that are used to tackle the problem above coherently.
Information extraction from such rich data sources using advanced
statistical methodologies is a challenging task due to the massive
volume of data. To solve this problem, in this paper, we present a
proposed unsupervised learning algorithm based on Principle
Component Analysis (PCA) technique. The algorithm is particularly
applied on an actual remote sensing spacecraft. Data from the
Attitude Determination and Control System (ADCS) was acquired
under two operation conditions: normal and faulty states. The models
were built and tested under these conditions, and the results show that
the algorithm could successfully differentiate between these
operations conditions. Furthermore, the algorithm provides
competent information in prediction as well as adding more insight
and physical interpretation to the ADCS operation.
Abstract: In this study, the commercial finite element software
ABAQUS was used to develop a three-dimensional nonlinear finite
element model capable of simulating the pull-out test of reinforcing
bars from underwater concrete. The results of thirty-two pull-out tests
that have different parameters were implemented in the software to
study the effect of the concrete cover, the bar size, the use of stirrups,
and the compressive strength of concrete. The interaction properties used in the model provided accurate
results in comparison with the experimental bond-slip results, thus
the model has successfully simulated the pull-out test. The results of
the finite element model are used to better understand and visualize
the distribution of stresses in each component of the model, and to
study the effect of the various parameters used in this study including
the role of the stirrups in preventing the stress from reaching to the
sides of the specimens.
Abstract: During machining process, chatter is an unavoidable
phenomenon. Boring bars possess the cantilever shape and due to
this, it is subjected to chatter. The adverse effect of chatter includes
the increase in temperature which will leads to excess tool wear. To
overcome these problems, in this investigation, Cartridge brass (Cu –
70% and Zn – 30%) is passively fixed on the boring bar and also
clearance is provided in order to reduce the displacement, tool wear
and cutting temperature. A conventional all geared lathe is attached
with vibrometer and pyrometer is used to measure the displacement
and temperature. The influence of input parameters such as cutting
speed, depth of cut and clearance on temperature, tool wear and
displacement are investigated for various cutting conditions. From
the result, the optimum conditions to obtain better damping in boring
process for chatter reduction is identified.
Abstract: This study, tries to suggest a design method based on
displacement using finite difference numerical modeling in
reinforcing soil retaining wall with steel strip. In this case, dynamic
loading characteristics such as duration, frequency, peak ground
acceleration, geometrical characteristics of reinforced soil structure
and type of the site are considered to correct the pseudo static method
and finally introduce the pseudo static coefficient as a function of
seismic performance level and peak ground acceleration. For this
purpose, the influence of dynamic loading characteristics,
reinforcement length, height of reinforced system and type of the site
are investigated on seismic behavior of reinforcing soil retaining wall
with steel strip. Numerical results illustrate that the seismic response
of this type of wall is highly dependent to cumulative absolute
velocity, maximum acceleration, and height and reinforcement length
so that the reinforcement length can be introduced as the main factor
in shape of failure. Considering the loading parameters, geometric parameters of the
wall and type of the site showed that the used method in this study
leads to efficient designs in comparison with other methods, which
are usually based on limit-equilibrium concept. The outputs show the
over-estimation of equilibrium design methods in comparison with
proposed displacement based methods here.
Abstract: This study focuses on the hydro-geology and chemical
constituents analysis of Ikogosi Warm Spring waters in South West
Nigeria. Ikogosi warm spring is a global tourist attraction because it
has both warm and cold spring sources. Water samples from the cold
spring, warm spring and the meeting point were collected, analyzed
and the result shows close similarity in temperature, hydrogen iron
concentration (pH), alkalinity, hardness, Calcium, Magnesium,
Sodium, Iron, total dissolved solid and heavy metals. The measured
parameters in the water samples are within World Health
Organisation standards for fresh water. The study of the geology of
the warm spring reveals that the study area is underlain by a group of
slightly migmatised to non-migmatised paraschists and meta-igneous
rocks. Also, concentration levels of selected heavy metals, (Copper,
Cadmium, Zinc, Arsenic and Cromium) were determined in the water
(ppm) samples. Chromium had the highest concentration value of
1.52ppm (an average of 49.67%) and Cadmium had the lowest
concentration with value of 0.15ppm (an average of 4.89%).
Comparison of these results showed that, their mean levels are within
the standard values obtained in Nigeria. It can be concluded that both
warm and spring water are safe for drinking.