Title: |
Optimization of
machining parameter for turning of EN 16 steel using grey based Taguchi method |
Author (s): |
P. Madhava Reddy, P. Vijaya Bhaskara Reddy, Y. Ashok Kumar Reddy
and
N. Naresh |
Abstract: |
This
paper presents the optimization of CNC turning parameters for
EN 16 steel bar using the Grey Taguchi Method. A plan of
experiments based on Taguchi’s L27 orthogonal
array was established and turning experiments were conducted
with prefixed cutting parameters for EN 16 steel bar using
tungsten carbide tool. The turning parameters are cutting
speed, feed rate and depth of cut and the responses are
surface finish and material removal rate. Taguchi’s
signal-to-noise (S/N) ratio are determined based on their
performance characteristics. A grey relational grade is
obtained by using S/N ratio. Based on grey relational grade
value, optimum levels of parameters have been identified by
using response Table and response graph and the significant
contributions of controlling parameters are estimated using
analysis of variances (ANOVA). |
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Title: |
Life cycle
assessment of thermal insulating building materials using
building information modeling |
Author (s): |
K. Jagruthi, N. Ciddarth and M. Ramesh Kannan |
Abstract: |
This paper discusses the
integrated whole-building process of achieving the most
economic and energy efficient design of a common residential
building through the sustainable design. This involves
positioning and orientation of the building with respect to
the annual sun path, adjusting the percentage of openings in
the building, usage of the low energy impact materials in
non-load bearing structures. Life cycle Analysis of the
materials to be used in the non-load bearing members has been
integrated in this analysis. Energy analysis of the materials
to determine the lower impact on the environment is computed
by the SimaPro software. The results thus obtained are used to
analyze the heating and cooling demand graphs using CASAnova.
The real time analysis and modeling of the typical building
is computed by Autodesk® AutoCAD® 2014, Autodesk® Revit®
2013, and Autodesk® Ecotect® Analysis 2010 by trial and
error method. All the dimensions are followed as prescribed in
the National Building Code 2005-Part 8. |
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Title: |
Markov based exploration for aircraft design time compression |
Author (s): |
Vasantharaju C., B. Ashok and C. D. Naiju |
Abstract: |
The design of Aircraft and especially the fighter
Aircraft is increasingly getting complex. Added to the
complexities of the design and need to integrate several
disciplines, there is an added challenge of working with
technologies that are still in drawing boards to be
incorporated in future design. Needless to add, validation and
testing of entire system / subsystem is a pain point. Hence there is a clear need to design the aircraft in
such a manner to accommodate for futuristic technologies and
compress the design cycle times. On an average, design and
development of a Military aircraft either for developed
countries or developing countries requires a minimum of 13
years from the launch of project to the first flight. As the
years get passed on new technologies and advancement also
develops and it will become difficult to identify and
incorporate to the ongoing projects. A novel approach of using Markov process for achieving
these objectives is explored. Markov based approach as a
stochastic approach normally used to predict future states on
the basis they have no link to the past is explored. A step by
step approach by taking a typical design life cycle process of
a particular component/assembly of aircraft is discussed. In
this, design is split in to sequential stages, based on our
prior design experience a probability is assigned to all
foreseeable possibilities, and then that is converted to
transition probability. Using a simple concept that any
probability less than 1.0 leads to extended design life cycle,
suitable cost and time factors. |
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|
Title: |
Three dimensional visualization for fast display of vector
fields using illuminated stream lines |
Author (s): |
Gunasekaran
G.
and Bimal Kumar Ray |
Abstract: |
A new technique for interactive
vector field visualization using large numbers of properly
illuminated stream lines is presented. Taking into account
ambient, diffuse, and specular reflection terms as well as
transparency, we employ a realistic shading model which
significantly increases quality and realism of the resulting
images. While many graphics workstation offer hardware support
for illuminating surface. Primitives, usually no means for an
accurate shading of line primitives are provided. However, we
show that proper illumination of lines can be implemented by
exploiting the texture mapping capabilities of modern graphics
hardware. In this way high rendering performance with
interactive frame rates can be achieved. We apply the
technique to render large numbers of integral curves in a
vector field. The impression of the resulting images can be
further improved by making the curves partially transparent.
We also describe methods for controlling the distribution of
stream lines in space. These methods enable us to use
illuminated stream lines within an interactive visualization
environment. |
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|
Title: |
Design of fuel tank baffles to reduce
kinetic energy produced by fuel sloshing and to enhance the
product life cycle |
Author (s): |
R. Thundil Karuppa Raj, T. Bageerathan and G.
Edison |
Abstract: |
Fuel sloshing occurs in vehicle
when it accelerates or decelerates. It generates high kinetic
energy with unpleasant noise. This fuel sloshing leads to
vehicle imbalance. This vehicle instability may occur when the
fuel to weight ratio is high. In automobiles, the fuel
sloshing generates unpleasant noise which is not expected from
the present ones. So, this work presents the use of baffles at
different positions in the fuel tank to suppress the fuel
sloshing. Generally this phenomenon is seen in High Density
Polyethylene (HDPE) tanks which are strong and light in
weight. Introduction of baffles in the HDPE tanks is an
onerous process through blow moulding. So the present work
mainly focuses on the simulation of the slosh experiments to
analyse the baffle design. The result depends upon the number
of baffles, location of the baffle and its shape. The highest
noise is generated only when the fuel hits the top of the
tank. The baffle is designed in such a way that these noises
are reduced. The height of the baffle should be sufficient
enough to reduce the flow of fuel. The work mainly focuses
over the selection of appropriate height of the baffle which
gives optimum result with less effect on the fuel capacity of
the tank. For this work, the fuel tank is modelled with
Solidworks 2011. The fuel tank is meshed in ICEM CFD. It is
solved in Ansys CFX 12.0. The Turbulent kinetic energy, force
and velocity produced by the fuel during sloshing are
calculated. The kinetic energy produced by the fuel produces
the stress at the ends when reaching the ends of the tank. So
the use of baffle reduced the noise and as well as the stress
created at the ends. The product life cycle of the tank is
also improved. |
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|
Title: |
Influence of cutting parameters on dry machining of
Inconel 625
alloy with coated carbide insert - A statistical approach |
Author (s): |
K. Venkatesan, R. Ramanujam, Vimal Saxena,
Nilendukar Chawdhury and Vikash Choudhary |
Abstract: |
This paper investigates the
influence of cutting parameters on machinability of a Ni-Cr
alloy, Inconel 625, with coated carbide inserts (PVD AlTiN).
In this work, a bar type Inconel 625 sample was chosen and
based on Taguchi’s L9 orthogonal array, turning experiments
were conducted at different levels of cutting speed, feed rate
and depth of cut. The performance measures, cutting force and
surface roughness, were measured to analyze the machining
effectiveness. The signal-to-noise (S/N) ratio, the analysis
of variance (ANOVA), and regression analysis were employed to
find the optimal levels and to analyze the effect of the
cutting parameters for the objective of lower cutting force
and better surface finish under dry cutting conditions. The
obtained results indicated that PVD coated inserts performed
better in terms of cutting force and surface roughness with
designed cutting parameters. The relationship between the
independent variables and dependent variables is determined
through a quadratic multiple regression model. From the
statistical analysis, the results show that surface roughness
is greatly influenced by feed rate and followed by cutting
speed. The feed rate exhibits the maximum influence on cutting
force components as compared to the depth of cut and cutting
speed. |
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|
Title: |
A CFD investigation on fluid dynamic gauging |
Author (s): |
R. Thundil
Karupparaj, Bharani Kumar K.V. and M.P. Dhyan Shankar |
Abstract: |
This study deals with
computational fluid dynamics (CFD) of fouling inside tubes or
passages. These cases arise in present industrial situations
involving fluid flows inside. The investigation on fouling is
carried out by the technique called fluid dynamic gauging (FDG),
which is a non-contact technique for measuring the thickness
of soft deposit layer on solid surfaces immersed in liquid
environment in situ and in real time. Laminar Newtonian flow
has been investigated with Reynolds number at the nozzle
throat in the range 116<Ret<930 and with the
flow velocity of 0.0015 m/s to 0.124 m/s with water as the
working fluid. The 3-dimensional model is created using
SOLIDWORKS software. The fluid domain is discretized using
finite volume method using ICEMCFD12.1 pre-processing tool.
Both hexahedral and tetragonal mesh is generated which is used
to capture the hydrodynamic boundary layers. The flow field
through the 3-dimensional domain is captured by solving the
appropriate governing equations namely conservation of mass
and momentum equations. The convergence criteria are set to
10E-04 for mass and momentum. The numerically predicted
results are compared with the experimental data available in
the literature and a very good agreement exists between the
two. Fouling phenomenon is calculated by finding the pressure
difference between inlet and gauge tube outlet. |
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Title: |
Empirical study on
outsourcing factors for collaborative product development in aircraft programmes in
India |
Author (s): |
G. Ramakrishnan
and Prakash Sai |
Abstract: |
The objective of this paper is to investigate the impact of factors that
contributes to the success of engineering and embedded systems
outsourcing in complex product development and to develop an
outsourcing framework for collaborative product development in
aircraft programmes in
India
. Based on the review of literature on complex product
development and strategic outsourcing, the potential factors
that determine the product development outsourcing outcome
have been identified. The factors are further validated
through a qualitative analysis with the experts in the field
with more than 20 years of experience. A survey instrument is
developed for data collection to validate the model. An
exploratory factor analysis has been done on the data
collected during the pilot study phase. An important insight
from this study is that the technical factors and process
factors play a crucial role in determining the outsourcing
outcome in the product development in aircraft industry. There
is a significant variation in the outcomes depending on the
discipline. The implementation factors are more relational in
nature with respect to R and D labs / PSUs and are more
contractual in nature when it comes to private industries. The
study has limitations of looking into the product development
outsourcing outcome of only one programme and from the client
perspective alone. |
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|
Title: |
New product development by DFMA and rapid prototyping |
Author (s): |
Wankhade Nitesh Prakash, V. G.
Sridhar and K. Annamalai |
Abstract: |
In any manufacturing process,
design is the first step where most of the important decisions
are made which affects the final cost of the product. In this
paper the researchers have used Design for manufacturing and
assembly (DFMA) to re-design a fluid flow control valve and
optimized its design to ensure the reduced number of parts,
safety, reliability, time to market and customer satisfaction.
In this research work the main emphasis was given to the
design stage of a product development to obtain an optimum
design solution for an existing product, DFMA concepts were
used to produce alternative design ideas and the rapid
prototyping process was used to develop a prototype for
testing and validation of these alternative designs. Optimum
design, low cost and good quality with quick delivery was the
outcome of this research work. |
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|
Title: |
Product lifecycle
management (PLM) implementation for
the airborne early warning and control (AEW and C) programme |
Author (s): |
Ashu Bhatia, Pradeep Raja, Sai
Gunaranjan and Ananth Nath Talla |
Abstract: |
The Programme Office (PO),
Centre for Airborne Systems (CABS), Defense Research and
Development Organization (DRDO) is tasked with the development
of the Airborne Early Warning and Control (AEW and C) System
for the Indian Air Force (IAF). Being a large System-of-System
Product, not only do the inherent product complexities through
controlled and traceable product development environment pose
numerous challenges but the requirement of spearheading and
managing the co-operation between the Work-Centres (WCs)
spread out across
India
is difficult. At
the very onset, the
PO
recognized the need to adopt and deploy a suite of
State-of-the-Art Hardware and Software that would focus on
leveraging the AEW and C Programme information to deliver the
system within time, cost and quality envisaged. The paper
brings out how the
PO
effectively faced the numerous challenges at both the Product
and Programme level through use of the Product Lifecycle
Management (PLM) Technology. |
|
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|
Title: |
On the sustainability of the ancient
Ratnagiri university complex: A design reconstruction study |
Author (s): |
S.
Ghosh, R. Mathew, P. Gupta,
A. Khanna and
S. Saha |
Abstract: |
Ratnagiri
University
was an ancient residential
Buddhist
University
that flourished during the period of 6th-12th century CE in
Orissa (20.6330N 86.3330E). In this study we seek to examine
the energy efficiency of the University’s edifices from a
fluid mechanical point of view, using the Software Autodesk®
Ecotect® and X-Flow. From a site visit, notable phenomena
such as stack ventilation effects in the multi storied
dormitories and acoustic filtering of high frequency sounds
were suggested upon examining the building forms, which
included stupas, courtyards, both windowless and windowed
rooms and numerous sculptures amongst a large medley of
archaeological remains. This study, the first ever to analyze
an ancient
Buddhist
University
, places a particular emphasis on the orientation, siting,
infiltration, ventilation, day lighting and acoustics. From
these analyses we seek to infer the prowess of the populace of
that period, concerning harness of natural resources and
design strategies. |
|
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|
Title: |
Effect of sky scrapers on natural ventilation
patterns and human comfort index in low-risebuildings - A CFD
analysis over central Mumbai |
Author (s): |
J. Nagawkar,
S. Ghosh, R. Kataria, A. Nashit
and A. Deora |
Abstract: |
Mumbai, the financial capital of India and one of the world’s largest Mega Cities by the sea, is witnessing a massive construction boom. This can be attributed to the rapid economic growth as well as increase in population density. The number of skyscrapers has escalated to 140 (as of 2012), highest in any Indian city, with several more in the pipeline. It is also home to 1480 high-rise buildings. These towering, sharp-edged structures produce great amount of frictional drag and create turbulence in the boundary layer, significantly impacting the low-rise buildings lying in their wake. A CFD analysis to simulate air flow patterns around Tardeo (Latitude: 18°58’21.95” N, Longitude: 72°48’44.19” E) in Mumbai, has been conducted using ANSYS CFX to obtain pressure and velocity profiles- these product modeling simulations are expected to inform green architects engaged in sustainable design enhancements. |
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Title: |
Investigations on the lubricated wear of
direct metal laser sintered components for functional
applications |
Author (s): |
C. D. Naiju, P. M. Anil, M. Mohan Prashanth and S. Karthik |
Abstract: |
Direct
Metal Laser Sintering(DMLS) is a sequential layered
manufacturing method to produce any desired three dimensional
parts with simple or complex shapes with no or minimum
post-processing. In this study Bronze-Nickel powder was used
to make the samples. The
samples were produced with the optimized set of parameters
such as sintering speed, scan spacing, hatch type, hatch
distance and infiltration based on previous studies. To
investigate the tribological behavior of the sintered
components for functional applications, reciprocating wear
tests under lubricated condition were carried out. A
ball-on-flat configuration was chosen for the tests. Using
Design of Experiments, Taguchi’s modified L9 orthogonal
Table has been implemented to carry out the experiments.
Hardness, load and temperature were the three parameters
considered and three levels were chosen for each to create the
orthogonal array. Wear tests were carried out with the set
parameters and wear rates of the DMLS samples were found out.
ANOVA statistical method was used to find the influence of
major parameter and the contribution of each parameter on the
wear rate of the samples. It has been found that the applied
load, one of the selected test parameters had more influence
on lubricated wear as compared to other parameters. |
|
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|
Title: |
Numerical analysis of helically coiled heat exchanger using CFD
technique |
Author (s): |
R. Thundil Karuppa Raj,
Manoj Kumar S, Aby Mathew C. and T. Elango |
Abstract: |
In the
present study, 3 dimensional numerical analysis of helically
coiled tube is carried out using commercial CFD tool ANSYS CFX
12.1. It is very difficult and time consuming if these
analyses could be carried out experimentally and hence in the
present work, efforts are taken to optimize the helically
coiled tube with respect to heat transfer and flow parameters
for various coil pitch. Analysis of heat exchanger is done
using conjugate heat transfer. The 3-dimensional flow through
the helically coiled tube is considered which would overcome
the anisotropic flow properties that would arise due to
complex turbulence phenomenon and flow deviations. The flow
field through the helically coiled tube is simulated by
solving the appropriate governing equations: conservation of
mass, momentum and energy. The turbulence is taken care by
Shear Stress Transport (SST) k-έ model of closure. SST k-έ has
a blending function which acts as standard k-έ in the main
stream flow and as Standard k-ω near the boundary layer where
the gradient is much steeper. The numerically predicted
results are compared with the experimental data available in
the literature and a very good agreement exists between the
experimental and numerically predicted data. |
|
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|
Title: |
Comparative study of monocoque and semi-monocoque
flight vehicle structures under structural and thermo-structural
loads |
Author (s): |
R Santhanam, P. C. Jain, Y Krishna
and PSR Anjaneyulu |
Abstract: |
Analysis of monocoque and semi-monocoque
cylindrical flight vehicle structures by using finite element
method has been carried out. Shell elements are used for
idealizing skin portions and end rings and beam elements are
used for idealizing stiffeners. The behaviour of these
structures is compared in terms of mass, deformation, stress
and buckling under structural and thermo-structural loads to
study the effect of number of longitudinal stiffeners. The
study shows that semi-monocoque structures give higher factor
of safety and buckling load factor when only structural loads
(axial force and bending moment) are acting on them and the
same structure give lesser factor of safety and buckling load
factor when thermal loads (temperatures) and structural loads
(axial force and bending moment) are acting on them in a
combined manner. It is concluded that monocoque structures are
best suitable under thermo-structural load environments. |
|
|
|
Title: |
Safety assessment of a light transport
aircraft (LTA) in the event of uncontained rotor burst and
propeller blade failure |
Author (s): |
Rashmi Hundekari and Abbani Rinku |
Abstract: |
Throughout the life cycle of an aircraft, it is likely that it may encounter an uncontained engine rotor or propeller blade failure due to probable malfunction or failure of single or multiple engine components, inadequate rotor and casing design, fatigue, material imperfections, assembly errors and foreign object ingestion. Uncontained engine rotor or propeller blade failure can lead to catastrophic failure if not addressed adequately during design. To ensure safety of the flight in the event of rotor burst or propeller blade failure federal aviation regulations has set forth compliance requirements (FAR sections 25.903, 25.905.d) which states that the airplane must be capable of successfully completing a flight during which likely structural damage occurs as a result of a propeller blade impact, uncontained fan blade impact, uncontained engine rotor failure or uncontained high energy rotating machinery failure. Aircraft manufactures has to comply with the safety requirements mentioned above. Hence it is required to assess the risk, take adequate design measures to minimize the risk and show compliance by analysis or test that the damage caused is minimal and aircraft is capable of completing safe flight in the event of uncontained rotor failure. This paper demonstrates the methodology to be followed for performing safety assessment of a typical light transport aircraft (LTA) in the event of an uncontained rotor burst and propeller blade failure. Assessment method presented in this paper is generic in nature and can be used to assess the safety of any class of transport aircraft. |
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|
Title: |
Prediction of residual tensile strength of laminated composite
plates after low velocity impact |
Author (s): |
V.
Balasubramani and S. Rajendra Boopathy |
Abstract: |
Laminated composite materials are extensively
used in aerospace and marine industries because of their
advantageous ratio between high stiffness and low weight as
well as high strength and low weight. However, in this
application these composites are subjected to low-velocity
impact due to birds, hail, and rain and from dropped tools
used during manufacture or maintenance. Low velocity impact
damage is often internal and invisible, but can minimize the
residual strength. In this study, the residual tensile
strength of three stacking sequences of Glass Fiber Reinforced
Plastic (GFRP) composites is determined after low velocity
impact experimentally using threshold energy. A model has been
selected based on linear elastic fracture mechanics for
predicting residual strength of impacted GFRP composites.
Experimental results show the reliability of the model in the
field of low velocity impact and its usefulness in determining
the residual tensile strength. The correlation between the
analytical and experimental results was found to be very good.
The determination of residual strength in impacted laminates
is very useful for predicting product-life cycle. |
|
|
|
Title: |
Variation of undrained shear strength of unsaturated porous
media with temperature and suction |
Author (s): |
Anuchit Uchaipichat |
Abstract: |
At present, the
thermo-hydro-mechanical coupling in unsaturated porous media
is an interested subject since the environmental issues have
been raised worldwide. Thus, this paper presents simulation
results of effects of temperature and suction on undrained
shear strength of unsaturated porous media, which is an
important parameter in geotechnical design and analysis. The
equation of undrained shear strength including thermal effect
was used to estimate the results at various temperatures and
matric suctions. Typically, the results show that the
undrained shear strength decreases with increasing temperature
for all values of matric suction. However, the undrained shear
strength increases with increasing matric suction for all
values of ambient temperature. |
|
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|
Title: |
Performance evaluation of diversified SVM kernel functions for
breast tumor early prognosis |
Author (s): |
Khondker Jahid Reza,
Sabira Khatun, Mohd
F. Jamlos, Md. Moslemuddin Fakir and Sheikh Shanawaz Mostafa |
Abstract: |
Ultra wide-band (UWB) microwave
technology is a promising candidate to detect the early breast
cancer. This paper aims to depict pattern recognition
performance of support vector machine (SVM) for confocal UWB
breast tumor imaging dataset. A novel feature extraction
technique is also introduced in this paper for the signal
classification perfectly and promptly. SVM classifier
functions the comparative study between SVM kernel functions
includes linear function, radial basis function, polynomial
and multi layer perceptions are investigated and verified for
pattern recognition performance with the help of receiver
operating characteristic (ROC) graph and confusion matrix. The
main motto of this paper is to identify the tumor in its
smallest dimension from available works including their data
using the proposed feature extraction. In total, thirteen
different sizes of benign tumors are being considered where
the smallest and largest tumor sizes utilized are 1mm and
9 mm, respectively. |
|
|
|
Title: |
Hygrothermal response of plant fiber reinforced composites |
Author (s): |
Christian
Sunday Chukwuekezie, Christopher
Chukwutoo Ihueze, Jamaliah
Idris and Gaius Debi Eyu |
Abstract: |
The effect of soaking time and
temperature response for coconut and raffia fibre reinforced
composite on their mechanical properties have been studied.
Tensile and compression test for treated and untreated were
performed using a universal testing machine (Monsanto
Tensometer). The conditioned samples in each case show better
tensile and compressive strength compared to the untreated
samples. Raffia fibre reinforced polyester showed a better
mechanical and moisture absorption properties at various
operating temperature in the study. |
|
|
|
Title: |
An overview of
isolation improvement techniques in RF switch |
Author (s): |
M. H. Abdul
Hadi, B. H. Ahmad, Peng Wen Wong and N. A. Shairi |
Abstract: |
In this
paper, five techniques to improve isolation of RF switch are
reviewed which are material with fabrication process design,
circuit design, resonant circuit, transmission line and
resonator. Most of these isolation improvement techniques are
applied in RF switch designs such as single pole single throw
(SPST) and single pole multi throw (SPMT). Several solid-state
devices are used for switching element such as PIN diode, MEMS,
FET, HBT and HEMT. They are commonly used in satelite
communication, radar system, instrumentation and base station
applications. |
|
|
|
Title: |
Simulation and evaluation of performance
parameters for PWM based interleaved boost converter for fuel
cell applications |
Author (s): |
M. Tamilarasi and R.
Seyezhai |
Abstract: |
In the present scenario,
renewable energy sources are playing an important role to
satisfy the requirements of customer’s demand. Among these
sources, fuel cell is an attractive technology as it provides
a clean and efficient source of electricity. But a suitable
power conditioner is required to convert the DC power of fuel
into useful AC power. This paper focuses on a four-phase
directly coupled Interleaved Boost Converter (IBC) as a
suitable interface for fuel cell applications based on pulse
width modulation technique. The proposed converter is
simulated in MATLAB/SIMULINK. Input current, inductor current
and output voltage ripple is studied. Various energy factors
have been computed and the results are verified. |
|
|
|
Title: |
Diagnosis of
stator fault in asynchronous machine using soft computing
methods |
Author (s): |
K. Vinoth
Kumar, S. Suresh Kumar, A. Immanuel Selvakumar and Vicky Jose |
Abstract: |
Stator
Winding Fault can be detected by monitoring any abnormality of
the Park’s spectrum. In this paper is presented a
fault-detection performance comparison between the Support
Vector Machine (SVM) and backpropagation algorithm (BP) using
experimental data for a healthy and faulty case. Support
Vector Machine and Backpropagation Algorithm provide
environments to develop fault-detection schemes because of
their multi-input- processing and its good generalization
capability. The training patterns are obtained using motor
current signature analysis (MCSA) and using Spectral Park’s
Vector. The neural networks are evaluated by means of the
cross- validation technique to determine easily the diagnosis
and severity of turn-to- turn faults. |
|
|
|
Title: |
Soret and Hall
Effect on MHD flow, heat and mass transfer over a vertical
stretching sheet in a porous medium due to heat generation |
Author (s): |
Mohammad Ali and Mohammad Shah
Alam |
Abstract: |
The present
study is considered by the effect of Soret and Hall current
due to heat generation on coupled heat and mass transfer by
megnetohydrodynamic (MHD) free convection over a permeable
vertical stretching sheet. The governing boundary layer
equations are formulated and transformed into a set of
similarity equations using dimensionless similarity variables.
The governing fundamental set of a system of non-linear
locally similar ordinary differential equations are solved
numerically by Runge-Kutta fourth-fifth order integration
scheme along with shooting technique. Numerical results for
dimensionless velocity, Temperature and concentration profiles
displayed graphically for pertinent parameters to show
interesting aspects of the solutions. Also the skin friction
coefficient, the rate of heat transfer and rate of
concentration are presented in Table 1. |
|
|
|
Title: |
Study on the
low temperature operability improvement of the heat pump
dryer using a solar collector and an air collector |
Author (s): |
I. S. Hwang and
Y. L. Lee |
Abstract: |
When drying
frozen materials using a heat pump dryer, frost is formed on
the evaporator, resulting in the liquid flood back of the
compressor. Therefore, in this paper, a numerical analysis was
conducted of a heat pump dryer with attached solar collector
and air collector in order to enhance the low temperature
performance of the heat pump dryer. According to the analysis
results, when the solar collector was used in the given
conditions, the low temperature performance was improved
through the increase of evaporating pressure by approximately
61 kPa. Also, the COP increased by a maximum of 1.5 compared
to the standard cycle. Meanwhile, when using the air
collector, the evaporating pressure increased by 209 kPa and
the COP increased by a maximum of 5.5 over the standard cycle.
Thus, it is found the air collector is more effective than the
solar collector in the considered conditions. |
|
|
|
Title: |
Medium of instruction (L1 versus
L2): Which is Which in
engineering education? |
Author (s): |
Victor Dagala Medugu
and Amirmudin Bin Udin |
Abstract: |
The main purpose of the study
was to establish the effects of National language (L1) as
supplement to English Language (L2) in teaching and learning
Motor Vehicle Mechanics (MVM) Trade as a pre- requisite course
for Automobile engineering training in Technical Colleges.
This was because of the massive failures of students in the
said subject compared to other related engineering courses.
Four specific objectives were stated to guide the study. Four
corresponding research questions and two hypotheses
respectively were stated based on the objectives and were
tested at 0.05 level of significance. The design of the study
was Quasi experimental (None equivalent) design covering all
Technical Colleges in the State that offers Motor Vehicle
Mechanics (MVM) Trade. There was no sampling technique used.
Twenty multiple choice objective questions were administered
by the researcher and the research assistant after face and
content validation. Test- Retest method was used to determine
the reliability of the items. Data collected were analysed
using mean, standard Deviation and t-test. The results showed
that the students taught (MVM) Trade using L1 as supplement
performed significantly better and had positive attitudes
towards MVM trade than those taught using L2. |
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Title: |
Numerical study of size-dependent
instability of NEMS considering molecular force and elastic
support conditions |
Author (s): |
Ameneh Langari, A.
Yekrangi, R. Soroush,
M. Fakhraei and M. K. Hafshejani |
Abstract: |
Nano-electromechanical systems (NEMS) sensors are recently
used as powerful medical detectors for detection of disease.
In this research paper, the modified couple stress non-classic
continuum theory is applied to examine the size effect on the
pull-in instability of beam-type NEMS sensor at submicron
separations considering the van der Waals attraction. The
proposed model takes the non-classic support conditions into
account using rotational springs at supported end of the
simply supported nano-beam. In order to solve the nonlinear
constitutive equation of the nano-beams, finite difference
numerical solution employed. The results reveal significant
influence of the size dependency, elastic support conditions
and van der Waals attraction on the pull-in characteristics of
beam-type NEMS. |
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