Abstract: Wireless sensors, also known as wireless sensor nodes,
have been making a significant impact on human daily life. The
Radio Frequency Identification (RFID) and Wireless Sensor Network
(WSN) are two complementary technologies; hence, an integrated
implementation of these technologies expands the overall
functionality in obtaining long-range and real-time information on the
location and properties of objects and people. An approach for
integrating ZigBee and RFID networks is proposed in this paper, to
create an energy-efficient network improved by the benefits of
combining ZigBee and RFID architecture. Furthermore, the
compatibility and requirements of the ZigBee device and
communication links in the typical RFID system which is presented
with the real world experiment on the capabilities of the proposed
RFID system.
Abstract: This paper presents the performance characteristics of
Darrieus-type vertical axis wind turbine (VAWT) with NACA airfoil
blades. The performance of Darrieus-type VAWT can be
characterized by torque and power. There are various parameters
affecting the performance such as chord length, helical angle, pitch
angle and rotor diameter. To estimate the optimum shape of Darrieustype
wind turbine in accordance with various design parameters, we
examined aerodynamic characteristics and separated flow occurring
in the vicinity of blade, interaction between flow and blade, and
torque and power characteristics derived from it. For flow analysis,
flow variations were investigated based on the unsteady RANS
(Reynolds-averaged Navier-Stokes) equation. Sliding mesh algorithm
was employed in order to consider rotational effect of blade. To
obtain more realistic results we conducted experiment and numerical
analysis at the same time for three-dimensional shape. In addition,
several parameters (chord length, rotor diameter, pitch angle, and
helical angle) were considered to find out optimum shape design and
characteristics of interaction with ambient flow. Since the NACA
airfoil used in this study showed significant changes in magnitude of
lift and drag depending on an angle of attack, the rotor with low drag,
long cord length and short diameter shows high power coefficient in
low tip speed ratio (TSR) range. On the contrary, in high TSR range,
drag becomes high. Hence, the short-chord and long-diameter rotor
produces high power coefficient. When a pitch angle at which airfoil
directs toward inside equals to -2° and helical angle equals to 0°,
Darrieus-type VAWT generates maximum power.
Abstract: For the last decade, researchers have started to focus
their interest on Multicast Group Key Management Framework. The
central research challenge is secure and efficient group key
distribution. The present paper is based on the Bit model based
Secure Multicast Group key distribution scheme using the most
popular absolute encoder output type code named Gray Code. The
focus is of two folds. The first fold deals with the reduction of
computation complexity which is achieved in our scheme by
performing fewer multiplication operations during the key updating
process. To optimize the number of multiplication operations, an
O(1) time algorithm to multiply two N-bit binary numbers which
could be used in an N x N bit-model of reconfigurable mesh is used
in this proposed work. The second fold aims at reducing the amount
of information stored in the Group Center and group members while
performing the update operation in the key content. Comparative
analysis to illustrate the performance of various key distribution
schemes is shown in this paper and it has been observed that this
proposed algorithm reduces the computation and storage complexity
significantly. Our proposed algorithm is suitable for high
performance computing environment.
Abstract: Broiler slaughter waste has become a major source of
pollution throughout the world. Utilization of broiler slaughter waste
by dry rendering process produced Rendered Chicken Oil (RCO), a
cheap raw material for biodiesel production and Carcass Meal a feed
ingredient for pets and fishes. Conversion of RCO into biodiesel may
open new vistas for generating wealth from waste besides controlling
the major havoc of environmental pollution. A two-step process to
convert RCO to good quality Biodiesel was invented. Acid catalysed
esterification of FFA followed by base catalysed transesterification of
triglycerides was carried out after meticulously standardizing the
methanol molar ratio, catalyst concentration, reaction temperature,
and reaction time to obtain the maximum biodiesel yield of 97.62%
and lowest glycerol yield of 6.96%. RCO biodiesel blend was tested
in a CRDI diesel engine. The results revealed that the blending of
commercial diesel with 20% RCO biodiesel (B20) lead to less engine
wear, a quieter engine and better fuel economy. The better lubricating
qualities of RCO B20 prevented over heating of engine, which
prolongs the engine life. RCO B20 can reduce the import of crude oil
and substantially reduce the engine emissions as proved by
significantly lower smoke levels, thus mitigating climatic changes.
Abstract: In this study, the three-dimensional cavitating
turbulent flow in a complete Francis turbine is simulated using
mixture model for cavity/liquid two-phase flows. Numerical analysis
is carried out using ANSYS CFX software release 12, and standard k-ε
turbulence model is adopted for this analysis. The computational
fluid domain consist of spiral casing, stay vanes, guide vanes, runner
and draft tube. The computational domain is discretized with a threedimensional
mesh system of unstructured tetrahedron mesh. The
finite volume method (FVM) is used to solve the governing equations
of the mixture model. Results of cavitation on the runner’s blades
under three different boundary conditions are presented and
discussed. From the numerical results it has been found that the
numerical method was successfully applied to simulate the cavitating
two-phase turbulent flow through a Francis turbine, and also
cavitation is clearly predicted in the form of water vapor formation
inside the turbine. By comparison the numerical prediction results
with a real runner; it’s shown that the region of higher volume
fraction obtained by simulation is consistent with the region of runner
cavitation damage.
Abstract: The growth in the demand of electrical energy is
leading to load on the Power system which increases the occurrence
of frequent oscillations in the system. The reason for the oscillations
is due to the lack of damping torque which is required to dominate
the disturbances of Power system. By using FACT devices, such as
Unified Power Flow Controller (UPFC) can control power flow,
reduce sub-synchronous resonances and increase transient stability.
Hence, UPFC is used to damp the oscillations occurred in Power
system. This research focuses on adapting the neuro fuzzy controller
for the UPFC design by connecting the infinite bus (SMIB - Single
machine Infinite Bus) to a linearized model of synchronous machine
(Heffron-Phillips) in the power system. This model gains the
capability to improve the transient stability and to damp the
oscillations of the system.
Abstract: A new approach has been developed to estimate the
load share and distribution of worm gear drives, and to calculate the
instantaneous tooth meshing stiffness. In the approach, the worm gear
drive was modelled as a series of spur gear slices, and each slice was
analyzed separately using the well-established formulae of spur gear
loading and stresses. By combining the results obtained for all slices,
the entire envolute worm gear set loading and stressing was obtained. The geometric modelling method presented allows tooth elastic
deformation and tooth root stresses of worm gear drives under
different load conditions to be investigated. Based on the slicing
method introduced in this study, the instantaneous meshing stiffness
and load share are obtained. In comparison with existing methods,
this approach has both good analysis accuracy and less computing
time.
Abstract: In Automotive Industry, sliding door systems that are
also used as body closures are safety members. Extreme product tests
are realized to prevent failures in design process, but these tests
realized experimentally result in high costs. Finite element analysis is
an effective tool used for design process. These analyses are used
before production of prototype for validation of design according to
customer requirement. In result of this, substantial amount of time
and cost is saved. Finite element model is created for geometries that are designed in
3D CAD programs. Different element types as bar, shell and solid,
can be used for creating mesh model. Cheaper model can be created
by selection of element type, but combination of element type that
was used in model, number and geometry of element and degrees of
freedom affects the analysis result. Sliding door system is a good
example which used these methods for this study. Structural analysis
was realized for sliding door mechanism by using FE models. As
well, physical tests that have same boundary conditions with FE
models were realized. Comparison study for these element types,
were done regarding test and analyses results then optimum
combination was achieved.
Abstract: The aim of the current work was to employ the finite
element method to model a slab, with a small hole across its width,
undergoing plastic plane strain deformation. The computational
model had, however, to be validated by comparing its results with
those obtained experimentally. Since they were in good agreement,
the finite element method can therefore be considered a reliable tool
that can help gain better understanding of the mechanism of ductile
failure in structural members having stress raisers. The finite element
software used was ANSYS, and the PLANE183 element was utilized.
It is a higher order 2-D, 8-node or 6-node element with quadratic
displacement behavior. A bilinear stress-strain relationship was used
to define the material properties, with constants similar to those of the
material used in the experimental study. The model was run for
several tensile loads in order to observe the progression of the plastic
deformation region, and the stress concentration factor was
determined in each case. The experimental study involved employing the visioplasticity
technique, where a circular mesh (each circle was 0.5 mm in
diameter, with 0.05 mm line thickness) was initially printed on the
side of an aluminum slab having a small hole across its width.
Tensile loading was then applied to produce a small increment of
plastic deformation. Circles in the plastic region became ellipses,
where the directions of the principal strains and stresses coincided
with the major and minor axes of the ellipses. Next, we were able to
determine the directions of the maximum and minimum shear
stresses at the center of each ellipse, and the slip-line field was then
constructed. We were then able to determine the stress at any point in
the plastic deformation zone, and hence the stress concentration
factor. The experimental results were found to be in good agreement
with the analytical ones.
Abstract: File sharing in networks is generally achieved using
Peer-to-Peer (P2P) applications. Structured P2P approaches are
widely used in adhoc networks due to its distributed and scalability
features. Efficient mechanisms are required to handle the huge
amount of data distributed to all peers. The intrinsic characteristics of
P2P system makes for easier content distribution when compared to
client-server architecture. All the nodes in a P2P network act as both
client and server, thus, distributing data takes lesser time when
compared to the client-server method. CHORD protocol is a resource
routing based where nodes and data items are structured into a 1-
dimensional ring. The structured lookup algorithm of Chord is
advantageous for distributed P2P networking applications. However,
structured approach improves lookup performance in a high
bandwidth wired network it could contribute to unnecessary overhead
in overlay networks leading to degradation of network performance.
In this paper, the performance of existing CHORD protocol on
Wireless Mesh Network (WMN) when nodes are static and dynamic
is investigated.
Abstract: This paper presents the local mesh co-occurrence
patterns (LMCoP) using HSV color space for image retrieval system.
HSV color space is used in this method to utilize color, intensity and
brightness of images. Local mesh patterns are applied to define the
local information of image and gray level co-occurrence is used to
obtain the co-occurrence of LMeP pixels. Local mesh co-occurrence
pattern extracts the local directional information from local mesh
pattern and converts it into a well-mannered feature vector using gray
level co-occurrence matrix. The proposed method is tested on three
different databases called MIT VisTex, Corel, and STex. Also, this
algorithm is compared with existing methods, and results in terms of
precision and recall are shown in this paper.
Abstract: The development of electric vehicle batteries have
resulted in very high energy density lithium-ion batteries. However,
this progress is accompanied by the risk of thermal runaway, which
can result in serious accidents. Heat pipes are heat exchangers that
are suitable to be applied in electric vehicle battery thermal
management for their lightweight, compact size and do not require
external power supply. This paper aims to examine experimentally a
Flat Plate Loop Heat Pipe (FPLHP) performance as a heat exchanger
in thermal management system of lithium-ion battery for electric
vehicle application. The heat generation of the battery was simulated
using a cartridge heater. Stainless steel screen mesh was used as the
capillary wick. Distilled water, alcohol and acetone were used as
working fluids with a filling ratio of 60%. It was found that acetone
gives the best performance that produces thermal resistance of 0.22
W/°C with 50°C evaporator temperature at heat flux load of 1.61
W/cm2.
Abstract: In the field of fashion design, 3D Mannequin is a kind
of assisting tool which could rapidly realize the design concepts.
While the concept of 3D Mannequin is applied to the computer added
fashion design, it will connect with the development and the
application of design platform and system. Thus, the situation
mentioned above revealed a truth that it is very critical to develop a
module of 3D Mannequin which would correspond with the necessity
of fashion design. This research proposes a concrete plan that
developing and constructing a system of 3D Mannequin with Kinect.
In the content, ergonomic measurements of objective human features
could be attained real-time through the implement with depth camera
of Kinect, and then the mesh morphing can be implemented through
transformed the locations of the control-points on the model by
inputting those ergonomic data to get an exclusive 3D mannequin
model. In the proposed methodology, after the scanned points from the
Kinect are revised for accuracy and smoothening, a complete human
feature would be reconstructed by the ICP algorithm with the method
of image processing. Also, the objective human feature could be
recognized to analyze and get real measurements. Furthermore, the
data of ergonomic measurements could be applied to shape morphing
for the division of 3D Mannequin reconstructed by feature curves. Due
to a standardized and customer-oriented 3D Mannequin would be
generated by the implement of subdivision, the research could be
applied to the fashion design or the presentation and display of 3D
virtual clothes. In order to examine the practicality of research
structure, a system of 3D Mannequin would be constructed with JAVA
program in this study. Through the revision of experiments the
practicability-contained research result would come out.
Abstract: Steady three-dimensional and two free surface waves
generated by moving bodies are presented, the flow problem to be
simulated is rich in complexity and poses many modeling challenges
because of the existence of breaking waves around the ship hull, and
because of the interaction of the two-phase flow with the turbulent
boundary layer. The results of several simulations are reported. The
first study was performed for NACA0012 of hydrofoil with different
meshes, this section is analyzed at h/c= 1, 0345 for 2D. In the second
simulation a mathematically defined Wigley hull form is used to
investigate the application of a commercial CFD code in prediction of
the total resistance and its components from tangential and normal
forces on the hull wetted surface. The computed resistance and wave
profiles are used to estimate the coefficient of the total resistance for
Wigley hull advancing in calm water under steady conditions. The
commercial CFD software FLUENT version 12 is used for the
computations in the present study. The calculated grid is established
using the code computer GAMBIT 2.3.26. The shear stress k-ωSST
model is used for turbulence modeling and the volume of fluid
technique is employed to simulate the free-surface motion. The
second order upwind scheme is used for discretizing the convection
terms in the momentum transport equations, the Modified HRIC
scheme for VOF discretization. The results obtained compare well
with the experimental data.
Abstract: Steady three-dimensional and two free surface waves
generated by moving bodies are presented, the flow problem to be
simulated is rich in complexity and poses many modeling challenges
because of the existence of breaking waves around the ship hull, and
because of the interaction of the two-phase flow with the turbulent
boundary layer. The results of several simulations are reported. The
first study was performed for NACA0012 of hydrofoil with different
meshes, this section is analyzed at h/c= 1, 0345 for 2D. In the second
simulation a mathematically defined Wigley hull form is used to
investigate the application of a commercial CFD code in prediction of
the total resistance and its components from tangential and normal
forces on the hull wetted surface. The computed resistance and wave
profiles are used to estimate the coefficient of the total resistance for
Wigley hull advancing in calm water under steady conditions. The
commercial CFD software FLUENT version 12 is used for the
computations in the present study. The calculated grid is established
using the code computer GAMBIT 2.3.26. The shear stress k-ωSST
model is used for turbulence modeling and the volume of fluid
technique is employed to simulate the free-surface motion. The
second order upwind scheme is used for discretizing the convection
terms in the momentum transport equations, the Modified HRIC
scheme for VOF discretization. The results obtained compare well
with the experimental data.
Abstract: The comprehensive CFD models have been used to
represent and study the heterogeneous combustion of biomass. In the
present work, the operation of a global flue gas circuit in the sugarcane
bagasse combustion, from wind boxes below primary air grate
supply, passing by bagasse insertion in swirl burners and boiler
furnace, to boiler bank outlet is simulated. It uses five different
meshes representing each part of this system located in sequence:
wind boxes and grate, boiler furnace, swirl burners, superheaters and
boiler bank. The model considers turbulence using standard k-ε,
combustion using EDM, radiation heat transfer using DTM with 16
ray directions and bagasse particle tracking represented by Schiller-
Naumann model. The results showed good agreement with expected
behavior found in literature and equipment design. The more detailed
results view in separated parts of flue gas system allows observing
some flow behaviors that cannot be represented by usual
simplifications like bagasse supply under homogeneous axial and
rotational vectors and others that can be represented using new
considerations like the representation of 26 thousand grate orifices by
144 rectangular inlets.
Abstract: There are many perceived advantages of microwave
ablation have driven researchers to develop innovative antennas to
effectively treat deep-seated, non-resectable hepatic tumors. In this
paper a coaxial antenna with a miniaturized sleeve choke has been
discussed for microwave interstitial ablation therapy, in order to
reduce backward heating effects irrespective of the insertion depth
into the tissue. Two dimensional Finite Element Method (FEM) is
used to simulate and measure the results of miniaturized sleeve choke
antenna. This paper emphasizes the importance of factors that can
affect simulation accuracy, which include mesh resolution, surface
heating and reflection coefficient. Quarter wavelength choke
effectiveness has been discussed by comparing it with the unchoked
antenna with same dimensions.
Abstract: Hypersonic flows around spatial vehicles during their reentry phase in planetary atmospheres are characterized by intense aerothermodynamics phenomena. The aim of this work is to analyze high temperature flows around an axisymmetric blunt body taking into account chemical and vibrational non-equilibrium for air mixture species and the no slip condition at the wall. For this purpose, the Navier-Stokes equations system is resolved by the finite volume methodology to determine the flow parameters around the axisymmetric blunt body especially at the stagnation point and in the boundary layer along the wall of the blunt body. The code allows the capture of shock wave before a blunt body placed in hypersonic free stream. The numerical technique uses the Flux Vector Splitting method of Van Leer. CFL coefficient and mesh size level are selected to ensure the numerical convergence.
Abstract: Reflux condensation occurs in vertical channels and tubes when there is an upward core flow of vapour (or gas-vapour mixture) and a downward flow of the liquid film. The understanding of this condensation configuration is crucial in the design of reflux condensers, distillation columns, and in loss-of-coolant safety analyses in nuclear power plant steam generators. The unique feature of this flow is the upward flow of the vapour-gas mixture (or pure vapour) that retards the liquid flow via shear at the liquid-mixture interface. The present model solves the full, elliptic governing equations in both the film and the gas-vapour core flow. The computational mesh is non-orthogonal and adapts dynamically the phase interface, thus produces a sharp and accurate interface. Shear forces and heat and mass transfer at the interface are accounted for fundamentally. This modeling is a big step ahead of current capabilities by removing the limitations of previous reflux condensation models which inherently cannot account for the detailed local balances of shear, mass, and heat transfer at the interface. Discretisation has been done based on finite volume method and co-located variable storage scheme. An in-house computer code was developed to implement the numerical solution scheme. Detailed results are presented for laminar reflux condensation from steam-air mixtures flowing in vertical parallel plate channels. The results include velocity and gas mass fraction profiles, as well as axial variations of film thickness.
Abstract: In this paper, a numerical simulation of a finned store
separating from a wing-pylon configuration has been studied and
validated. A dynamic unstructured tetrahedral mesh approach is
accomplished by using three grid sizes to numerically solving the
discretized three dimensional, inviscid and compressible Euler
equations. The method used for computations of separation of an
external store assuming quasi-steady flow condition. Computations of
quasi-steady flow have been directly coupled to a six degree-offreedom
(6DOF) rigid-body motion code to generate store
trajectories. The pressure coefficients at four different angular cuts
and time histories of various trajectory parameters and wing pressure
distribution during the store separation are compared for every grid
size with published experimental data.