Abstract: In this paper a novel, simple and reliable digital firing
scheme has been implemented for speed control of three-phase
induction motor using ac voltage controller. The system consists of
three-phase supply connected to the three-phase induction motor via
three triacs and its control circuit. The ac voltage controller has three
modes of operation depending on the shape of supply current. The
performance of the induction motor differs in each mode where the
speed is directly proportional with firing angle in two modes and
inversely in the third one. So, the control system has to detect the
current mode of operation to choose the correct firing angle of triacs.
Three sensors are used to feed the line currents to control system to
detect the mode of operation. The control strategy is implemented
using a low cost Xilinx Spartan-3E field programmable gate array
(FPGA) device. Three PI-controllers are designed on FPGA to
control the system in the three-modes. Simulation of the system is
carried out using PSIM computer program. The simulation results
show stable operation for different loading conditions especially in
mode 2/3. The simulation results have been compared with the
experimental results from laboratory prototype.
Abstract: E-Learning systems are used by many learners and
teachers. The developer is developing the e-Learning system. However,
the developer cannot do system construction to satisfy all of
users- demands. We discuss a method of constructing e-Learning
systems where learners and teachers can design, try to use, and share
extending system functions that they want to use; which may be nally
added to the system by system managers.
Abstract: The significant effects of the interactions between the
system boundaries and the near wall molecules in miniaturized
gaseous devices lead to the formation of the Knudsen layer in which
the Navier-Stokes-Fourier (NSF) equations fail to predict the correct
associated phenomena. In this paper, the well-known lattice
Boltzmann method (LBM) is employed to simulate the fluid flow and
heat transfer processes in rarefied gaseous micro media. Persuaded
by the problematic deficiency of the LBM in capturing the Knudsen
layer phenomena, present study tends to concentrate on the effective
molecular mean free path concept the main essence of which is to
compensate the incapability of this mesoscopic method in dealing
with the momentum and energy transport within the above mentioned
kinetic boundary layer. The results show qualitative and quantitative
accuracy comparable to the solutions of the linearized Boltzmann
equation or the DSMC data for the Knudsen numbers of O (1) .
Abstract: Natural gas usually includes H2S component which is
very toxic, hazardous and corrosive to environment, human being and
process equipments, respectively. Therefore, sweetening of the gas
(separation of H2S) is inevitable. To achieve this purpose, using
packed-bed columns with liquid absorbents such as MEA or DEA is
very common. Due to some problems of usual packed columns
especially high pressure drop of gas phase, a novel kind of them
called wetted-wire column (WWC) has been invented. The column
decreases the pressure drop significantly and improves the absorption
efficiency. The packings are very thin rods (like wire) and as long as
column. The column has 100 wires with a triangular arrangement and
counter current flows of gas and liquid phases. The observation
showed that at the same conditions, the absorption performance was
quite comparable to conventional packed-bed towers and a very low
pressure drop.
Abstract: This paper details a new concept of using compressed air as a potential zero pollution power source for motorbikes. In place of an internal combustion engine, the motorbike is equipped with an air turbine transforms the energy of the compressed air into shaft work. The mathematical modeling and performance evaluation of a small capacity compressed air driven vaned type novel air turbine is presented in this paper. The effect of isobaric admission and adiabatic expansion of high pressure air for different rotor diameters, casing diameters and ratio of rotor to casing diameters of the turbine have been considered and analyzed. It is concluded that the work output is found optimum for some typical values of rotor / casing diameter ratios. In this study, the maximum power works out to 3.825 kW (5.20 HP) for casing diameter of 200 mm and rotor to casing diameter ratio of 0.65 to 0.60 which is sufficient to run motorbike.
Abstract: The present study was conducted to observe the effect
of Plantago psyllium on blood glucose and cholesterol levels in
normal and alloxan induced diabetic rats. To investigate the effect of
Plantago psyllium 40 rats were included in this study divided into
four groups of ten rats in each group. One group A was normal,
second group B was diabetic, third group C was non diabetic and
hypercholesterolemic and fourth group D was diabetic and
hypercholesterolemic. Two groups B and D were made diabetic by
intraperitonial injection of alloxan dissolved in 1mL distilled water at
a dose of 125mg/Kg of body weight. Two groups C and D were
made hypercholesterolemic by oral administration of powder
cholesterol (1g/Kg of body weight). The blood samples from all the
rats were collected from coccygial vein on 1st day, then on 21st and
42nd day respectively. All the samples were analyzed for blood
glucose and cholesterol level by using enzymatic kits. The blood
glucose and cholesterol levels of treated groups of rats showed
significant reduction after 7 weeks of treatment with Plantago
psyllium. By statistical analysis of results it was found that Plantago
psyllium has anti-diabetic and hypocholesterolemic activity in
diabetic and hypercholesterolemic albino rats.
Abstract: The main criteria of designing in the most hydraulic
constructions essentially are based on runoff or discharge of water. Two of those important criteria are runoff and return period. Mostly,
these measures are calculated or estimated by stochastic data.
Another feature in hydrological data is their impreciseness.
Therefore, in order to deal with uncertainty and impreciseness, based
on Buckley-s estimation method, a new fuzzy method of evaluating hydrological measures are developed. The method introduces
triangular shape fuzzy numbers for different measures in which both
of the uncertainty and impreciseness concepts are considered. Besides, since another important consideration in most of the
hydrological studies is comparison of a measure during different
months or years, a new fuzzy method which is consistent with special form of proposed fuzzy numbers, is also developed. Finally, to
illustrate the methods more explicitly, the two algorithms are tested on one simple example and a real case study.
Abstract: The use of Inverse Discrete Fourier Transform (IDFT) implemented in the form of Inverse Fourier Transform (IFFT) is one of the standard method of reconstructing Magnetic Resonance Imaging (MRI) from uniformly sampled K-space data. In this tutorial, three of the major problems associated with the use of IFFT in MRI reconstruction are highlighted. The tutorial also gives brief introduction to MRI physics; MRI system from instrumentation point of view; K-space signal and the process of IDFT and IFFT for One and two dimensional (1D and 2D) data.
Abstract: One very interesting field of research in Pattern Recognition that has gained much attention in recent times is Gesture Recognition. In this paper, we consider a form of dynamic hand gestures that are characterized by total movement of the hand (arm) in space. For these types of gestures, the shape of the hand (palm) during gesturing does not bear any significance. In our work, we propose a model-based method for tracking hand motion in space, thereby estimating the hand motion trajectory. We employ the dynamic time warping (DTW) algorithm for time alignment and normalization of spatio-temporal variations that exist among samples belonging to the same gesture class. During training, one template trajectory and one prototype feature vector are generated for every gesture class. Features used in our work include some static and dynamic motion trajectory features. Recognition is accomplished in two stages. In the first stage, all unlikely gesture classes are eliminated by comparing the input gesture trajectory to all the template trajectories. In the next stage, feature vector extracted from the input gesture is compared to all the class prototype feature vectors using a distance classifier. Experimental results demonstrate that our proposed trajectory estimator and classifier is suitable for Human Computer Interaction (HCI) platform.
Abstract: Phase transformation temperature is one of the most important parameters for the shape memory alloys (SMAs). The most popular method to determine these phase transformation temperatures is the Differential Scanning Calorimeter (DSC), but due to the limitation of the DSC testing itself, it made it difficult for the finished product which is not in the powder form. A novel method which uses the Universal Testing Machine has been conducted to determine the phase transformation temperatures. The Flexinol wire was applied with force and maintained throughout the experiment and at the same time it was heated up slowly until a temperature of approximately 1000C with direct current. The direct current was then slowly decreased to cool down the temperature of the Flexinol wire. All the phase transformation temperatures for Flexinol wire were obtained. The austenite start at 52.540C and austenite finish at 60.900C, while martensite start at 44.780C and martensite finish at 32.840C.
Abstract: The heart tissue is an excitable media. A Cellular
Automata is a type of model that can be used to model cardiac action
potential propagation. One of the advantages of this approach against
the methods based on differential equations is its high speed in large
scale simulations. Recent cellular automata models are not able to
avoid flat edges in the result patterns or have large neighborhoods. In
this paper, we present a new model to eliminate flat edges by
minimum number of neighbors.
Abstract: In this paper a new Joint Adaptive Block Matching
Search (JABMS) algorithm is proposed to generate motion vector
and search a best match macro block by classifying the motion vector
movement based on prediction error. Diamond Search (DS)
algorithm generates high estimation accuracy when motion vector is
small and Adaptive Rood Pattern Search (ARPS) algorithm can
handle large motion vector but is not very accurate. The proposed
JABMS algorithm which is capable of considering both small and
large motions gives improved estimation accuracy and the
computational cost is reduced by 15.2 times compared with
Exhaustive Search (ES) algorithm and is 1.3 times less compared
with Diamond search algorithm.
Abstract: This study attempts to clarify major perspectives of Corporate Social Responsibility (CSR) in the Greek market related to companies that have sufficient CSR. An empirical analysis was undertaken, based on literature review and previous observations and surveys, in order to provide a general analysis of the CSR concept in Greece. The results of Accountability Rating institution were used in order to identify companies that adopt an integrated social responsibility approach. Companies that responded to the survey are both regional and international and belong to different industrial fields. Some of the main survey results reveal: multiple aspects for the CSR concept, weak consensus as regards the importance of stakeholders and benefits from the CSR implementation, the important role of CSR in the decision procedure and CSR practices concerning social issues that affect mostly company-s competitiveness. Sharing companies- experience could address common social issues through CSR best practices and develop new knowledge.
Abstract: In order to obtaining the dynamic evolution image of Tungsten array for foam padding, and to research the form of interaction between Tungsten plasma and foam column, a shadow imaging system of four-frame ultraviolet probe laser (266nm)has been designed on 1MA pulse power device. The time resolution of the system is 2.5ns, and static space resolution is superior to 70μm. The radial shadowgraphy image reveals the whole process from the melting and expansion of solid wire to the interaction of the precursor plasma and the foam, from the pinch to rebound inflation. The image shows the continuous interaction of Tungsten plasma and foam in a form of “Raining" within a time of about 50ns, the plasma shell structure has not been found in the whole period of pinch. The quantitative analysis indicates the minimum pinching speed of the foam column is 1.0×106cm/s, and maximum pinching speed is 6.0×106cm/s, and the axial stagnation diameter is approx 1mm.
Abstract: Tailor-welded Blanks (TWBs) are tailor made for
different complex component designs by welding multiple metal
sheets with different thicknesses, shapes, coatings or strengths prior
to forming. In this study the Hemispherical Die Stretching (HDS) test
(out-of-plane stretching) of TWBs were simulated via
ABAQUS/Explicit to obtain the Forming Limit Diagrams (FLDs) of
Stainless steel (AISI 304) laser welded blanks with different
thicknesses. Two criteria were used to detect the start of necking to
determine the FLD for TWBs and parent sheet metals. These two
criteria are the second derivatives of the major and thickness strains
that are given from the strain history of simulation. In the other word,
in these criteria necking starts when the second derivative of
thickness or major strain reaches its maximum. With having the time
of onset necking, one can measure the major and minor strains at the
critical area and determine the forming limit curve.
Abstract: An application framework provides a reusable
design and implementation for a family of software systems.
Frameworks are introduced to reduce the cost of a product line
(i.e., family of products that share the common features). Software
testing is a time consuming and costly ongoing activity during the
application software development process. Generating reusable test
cases for the framework applications at the framework
development stage, and providing and using the test cases to test
part of the framework application whenever the framework is used
reduces the application development time and cost considerably.
Framework Interface Classes (FICs) are classes introduced by
the framework hooks to be implemented at the application
development stage. They can have reusable test cases generated at
the framework development stage and provided with the
framework to test the implementations of the FICs at the
application development stage. In this paper, we conduct a case
study using thirteen applications developed using three
frameworks; one domain oriented and two application oriented.
The results show that, in general, the percentage of the number of
FICs in the applications developed using domain frameworks is, on
average, greater than the percentage of the number of FICs in the
applications developed using application frameworks.
Consequently, the reduction of the application unit testing time
using the reusable test cases generated for domain frameworks is,
in general, greater than the reduction of the application unit testing
time using the reusable test cases generated for application
frameworks.
Abstract: Over the course of the past century, the global
automotive industry-s stance towards safety has evolved from one of
contempt to one nearing reverence. A suspension system that
provides safe handling and cornering capabilities can, with the help
of an efficient braking system, improve safety to a large extent. The
aim of this research is to propose a new automotive brake rotor
design and to compare it with automotive vented disk rotor. Static
structural and transient thermal analysis have been carried out on the
vented disk rotor and proposed rotor designs to evaluate and compare
their performance. Finite element analysis was employed for both
static structural and transient thermal analysis. Structural analysis
was carried out to study the stress and deformation pattern of the
rotors under extreme loads. Time varying temperature load was
applied on the rotors and the temperature distribution was analysed
considering cooling parameters (convection and radiation). This
dissertation illustrates the use of Finite Element Methods to examine
models, concluding with a comparative study of the proposed rotor
design and the conventional vented disk rotor for structural stability
and thermal efficiency.
Abstract: An attempt has been made to beneficiate the Indian
coking coal fines by a combination of Spiral, flotation and Oleo
Flotation processes. Beneficiation studies were also carried out on -
0.5mm coal fines using flotation and oleo flotation by splitting at size
0.063mm.Size fraction of 0.5mm-0.063mm and -0.063mm size were
treated in flotation and Oleo flotation respectively. The washability
studies on the fraction 3-0.5 mm indicated that good separation may
be achieved when it is fed in a spiral. Combined product of Spiral,
Flotation and Oleo Flotation has given a significant yield at
acceptable ash%. Studies were also conducted to see the dewatering
of combined product by batch type centrifuge. It may further be
suggested that combination of different processes may be used to
treat the -3 mm fraction in an integrated manner to achieve the yield
at the desired ash level. The treatment of the 3/1 mm -0.5 mm size
fraction by spiral,-0.5-0.63 mm by conventional froth flotation and -
0.063 fractions by oleo flotation may provide a complete solution of
beneficiation and dewatering of coal fines, and can effectively
address the environmental problems caused by coal fines.
Abstract: Research in e-Business has been growing
tremendously covering all related aspects such as adoption issues, e-
Business models, strategies, etc. This research aims to explore the
potential of adopting e-Business for a micro size business operating
from home called home-based businesses (HBBs). In Malaysia, the
HBB industry started many years ago and were mostly monopolized
by women or housewives managed as a part-time job to support their
family economy. Today, things have changed. The availability of the
Internet technology and the emergence of e-Business concept
promote the evolution of HBBs, which have been adopted as another
alternative as a professional career for women without neglecting
their family needs especially the children. Although this study is
confined to a limited sample size and within geographical biasness,
the findings show that it concurs with previous large scale studies. In
this study, both qualitative and quantitative methods were used and
data were gathered using triangulation methods via interview, direct
observation, document analysis and survey questionnaires. This paper
discusses the literature review, research methods and findings
pertaining to e-Business adoption factors that influence the HBBs in
Malaysia.
Abstract: This paper presents the development of an active
vibration control using direct adaptive controller to suppress the
vibration of a flexible beam system. The controller is realized based
on linear parametric form. Differential evolution optimisation
algorithm is used to optimize the controller using single objective
function by minimizing the mean square error of the observed
vibration signal. Furthermore, an alternative approach is developed to
systematically search for the best controller model structure together
with it parameter values. The performance of the control scheme is
presented and analysed in both time and frequency domain.
Simulation results demonstrate that the proposed scheme is able to
suppress the unwanted vibration effectively.