Abstract: It has experimentally been proved that the
performance of compression ignition (C.I.) engine is spray
characteristics related. In modern diesel engine the spray formation
and the eventual combustion process are the vital processes that offer
more challenges towards enhancing the engine performance. In the
present work the numerical simulation has been carried out for
evaporating diesel sprays using Fluent software. For computational
fluid dynamics simulation “Meshing” is done using Gambit software
before transmitting it into Fluent. The simulation is carried out using
hot bomb conditions under varying chamber conditions such as gas
pressure, nozzle diameter and fuel injection pressure. For comparison
purpose, the numerical simulations the chamber conditions were kept
the same as that of the experimental data. At varying chamber
conditions the spray penetration rates are compared with the existing
experimental results.
Abstract: Company managers are always looking for more and
more opportunities to succeed in today's fiercely competitive market.
To maintain your place among the successful companies on the
market today or to come up with a revolutionary business idea is
much more difficult than before. Each new or improved method, tool,
or approach that can improve the functioning of business processes or
even of the entire system is worth checking and verification. The use
of simulation in the design of manufacturing systems and their
management in practice is one of the ways without increased risk,
which makes it possible to find the optimal parameters of
manufacturing processes and systems. The paper presents an example
of use of simulation for solution of the bottleneck problem in the
concrete company.
Abstract: The spring-driven ball-type check valve is one of the
most important components of hydraulic systems: it controls the
position of the ball and prevents backward flow. To simplify the
structure, the spring must be eliminated, and to accomplish this, the
flow pattern and the behavior of the check ball in L-shaped pipe must
be determined. In this paper, we present a full-scale model of a check
ball made of acrylic resin, and we determine the relationship between
the initial position of the ball, the position and diameter of the inflow
port. The check flow rate increases in a standard center inflow model,
and it is possible to greatly decrease the check-flow rate by shifting the
inflow from the center.
Abstract: Conventional educational practices, do not offer all
the required skills for teachers to successfully survive in today’s
workplace. Due to poor professional training, a big gap exists across
the curriculum plan and the teacher practices in the classroom. As
such, raising the quality of teaching through ICT-enabled training and
professional development of teachers should be an urgent priority.
‘Mobile Learning’, in that vein, is an increasingly growing field of
educational research and practice across schools and work places. In
this paper, we propose a novel Mobile learning system that allows the
users to learn through an intelligent mobile learning in cooperatively
every-time and every-where. The system will reduce the training cost
and increase consistency, efficiency, and data reliability. To establish
that our system will display neither functional nor performance
failure, the evaluation strategy is based on formal observation of
users interacting with system followed by questionnaires and
structured interviews.
Abstract: Job Scheduling plays an important role for efficient
utilization of grid resources available across different domains and
geographical zones. Scheduling of jobs is challenging and NPcomplete.
Evolutionary / Swarm Intelligence algorithms have been
extensively used to address the NP problem in grid scheduling.
Artificial Bee Colony (ABC) has been proposed for optimization
problems based on foraging behaviour of bees. This work proposes a
modified ABC algorithm, Cluster Heterogeneous Earliest First Min-
Min Artificial Bee Colony (CHMM-ABC), to optimally schedule
jobs for the available resources. The proposed model utilizes a novel
Heterogeneous Earliest Finish Time (HEFT) Heuristic Algorithm
along with Min-Min algorithm to identify the initial food source.
Simulation results show the performance improvement of the
proposed algorithm over other swarm intelligence techniques.
Abstract: The prepreg process among the CFRP (Carbon Fiber
Reinforced Plastic) forming methods is the short term of
‘Pre-impregnation’, which is widely used for aerospace composites
that require a high quality property such as a fiber-reinforced woven
fabric, in which an epoxy hardening resin is impregnated the reality.
However, that this process requires continuous researches and
developments for its commercialization because the delamination
characteristically develops between the layers when a great weight is
loaded from outside to supplement such demerit, three lamination
methods among the prepreg lamination methods of CFRP were
designed to minimize the delamination between the layers due to
external impacts. Further, the newly designed methods and the
existing lamination methods were analyzed through a mechanical
characteristic test, Interlaminar Shear Strength test. The Interlaminar
Shear Strength test result confirmed that the newly proposed three
lamination methods, i.e. the Roll, Half and Zigzag laminations,
presented more excellent strengths compared to the conventional Ply
lamination. The interlaminar shear strength in the roll method with
relatively dense fiber distribution was approximately 1.75% higher
than that in the existing ply lamination method, and in the half method,
it was approximately 0.78% higher.
Abstract: In this paper, the electromagnetic shielding
characteristics of an up-to-date typical carbon filler material, carbon
fiber used with a metal mesh were investigated. Carbon fiber
12k-prepregs, where carbon fibers were impregnated with epoxy, were
laminated with wire meshes, vacuum bag-molded and hardened to
manufacture hybrid-type specimens, with which an electromagnetic
shield test was performed in accordance with ASTM D4935-10,
through which was known as the most excellent reproducibility is
obtainable among electromagnetic shield tests. In addition, glass fiber
prepregs whose electromagnetic shielding effect were known as
insignificant were laminated and formed with wire meshes to verify
the validity of the electromagnetic shield effect of wire meshes in
order to confirm the electromagnetic shielding effect of metal meshes
corresponding existing carbon fiber 12k-prepregs. By grafting carbon
fibers, on which studies are being actively underway in the
environmental aspects and electromagnetic shielding effect, with
hybrid-type wire meshes that were analysed through the tests, in this
study, the applicability and possibility are proposed.
Abstract: The development, operation and maintenance of
Integrated Waste Management Systems (IWMS) affects essentially
the sustainable concern of every region. The features of such systems
have great influence on all of the components of sustainability. In
order to reach the optimal way of processes, a comprehensive
mapping of the variables affecting the future efficiency of the system
is needed such as analysis of the interconnections among the
components and modeling of their interactions. The planning of a
IWMS is based fundamentally on technical and economical
opportunities and the legal framework. Modeling the sustainability
and operation effectiveness of a certain IWMS is not in the scope of
the present research. The complexity of the systems and the large
number of the variables require the utilization of a complex approach
to model the outcomes and future risks. This complex method should
be able to evaluate the logical framework of the factors composing
the system and the interconnections between them. The authors of
this paper studied the usability of the Fuzzy Cognitive Map (FCM)
approach modeling the future operation of IWMS’s. The approach
requires two input data set. One is the connection matrix containing
all the factors affecting the system in focus with all the
interconnections. The other input data set is the time series, a
retrospective reconstruction of the weights and roles of the factors.
This paper introduces a novel method to develop time series by
content analysis.
Abstract: This study examines several critical dimensions of eservice
quality overlooked in the existing literature and proposes a
model and instrument framework for measuring customer perceived
e-service quality in the banking sector. The initial design was derived
from a pool of instrument dimensions and their items from the
existing literature review by content analysis. Based on focused
group discussion, nine dimensions were extracted. An exploratory
factor analysis approach was applied to data from a survey of 323
respondents. The instrument has been designed specifically for the
banking sector. Research data was collected from bank customers
who use electronic banking in a developing economy. A nine-factor
instrument has been proposed to measure the e-service quality. The
instrument has been checked for reliability. The validity and sample
place limited the applicability of the instrument across economies and
service categories. Future research must be conducted to check the
validity. This instrument can help bankers in developing economies
like India to measure the e-service quality and make improvements.
The present study offers a systematic procedure that provides insights
on to the conceptual and empirical comprehension of customer
perceived e-service quality and its constituents.
Abstract: Fracture in hot precision forging of engine valves was
investigated in this paper. The entire valve forging procedure was
described and the possible cause of the fracture was proposed. Finite
Element simulation was conducted for the forging process, with
commercial Finite Element code DEFORMTM. The effects of
material properties, the effect of strain rate and temperature were
considered in the FE simulation. Two fracture criteria were discussed
and compared, based on the accuracy and reliability of the FE
simulation results. The selected criterion predicted the fracture
location and shows the trend of damage increasing with good
accuracy, which matches the experimental observation. Additional
modification of the punch shapes was proposed to further reduce the
tendency of fracture in forging. Finite Element comparison shows a
great potential of such application in the mass production.
Abstract: In this work, we study the behavior of introducing
atomic size vacancy in a graphene nanoribbon superlattice. Our
investigations are based on the density functional theory (DFT) with
the Local Density Approximation in Atomistix Toolkit (ATK). We
show that, in addition to its shape, the position of vacancy has a
major impact on the electrical properties of a graphene nanoribbon
superlattice. We show that the band gap of an armchair graphene
nanoribbon may be tuned by introducing an appropriate periodic
pattern of vacancies. The band gap changes in a zig-zag manner
similar to the variation of band gap of a graphene nanoribbon by
changing its width.
Abstract: This research study is an exploration of the selfdirected
professional development of teachers who teach in public
schools in an era of democracy and educational change in South
Africa. Amidst an ever-changing educational system, the teachers in
this study position themselves as self-directed teacher-learners where
they adopt particular learning practices which enable change within
the broader discourses of public schooling. Life-story interviews
were used to enter into the private and public spaces of five teachers
which offer glimpses of how particular systems shaped their
identities, and how the meanings of self-directed teacher-learner
shaped their learning practices. Through the Multidimensional
Framework of Analysis and Interpretation the teachers’ stories were
analysed through three lenses: restorying the field texts - the self
through story; the teacher-learner in relation to social contexts, and
practices of self-directed learning. This study shows that as teacherlearners
learn for change through self-directed learning practices,
they develop their agency as transformative intellectuals, which is
necessary for the reworking of South African public schools.
Abstract: Fructo-oligosaccharides (FOS) are produced from
sucrose by Aureobasidium pullulans in yields between 40-60%
(w/w). To increase the amount of FOS it is necessary to remove the
small, non-prebiotic sugars, present. Two methods for producing
high-purity FOS have been developed: the use of microorganisms
able to consume small saccharides; and the use of continuous
chromatography to separate sugars: simulated moving bed (SMB). It
is herein proposed the combination of both methods. The aim of this
study is to optimize the composition of the fermentative broth (in
terms of salts and sugars) that will be further purified by SMB. A
yield of 0.63 gFOS.gSucrose^-1 was obtained with A. pullulans using low
amounts of salts in the initial fermentative broth. By removing the
small sugars, Saccharomyces cerevisiae and Zymomonas mobilis
increased the percentage of FOS from around 56.0% to 83% (w/w) in
average, losing only 10% (w/w) of FOS during the recovery process.
Abstract: A new method for determining the distribution of
birefringence and linear dichroism in optical polymer materials is
presented. The method is based on the use of polarizationholographic
diffraction grating that forms an orthogonal circular basis
in the process of diffraction of probing laser beam on the grating. The
intensities ratio of the orders of diffraction on this grating enables the
value of birefringence and linear dichroism in the sample to be
determined. The distribution of birefringence in the sample is
determined by scanning with a circularly polarized beam with a
wavelength far from the absorption band of the material. If the
scanning is carried out by probing beam with the wavelength near to
a maximum of the absorption band of the chromophore then the
distribution of linear dichroism can be determined. An appropriate
theoretical model of this method is presented. A laboratory setup was
created for the proposed method. An optical scheme of the laboratory
setup is presented. The results of measurement in polymer films with
two-dimensional gradient distribution of birefringence and linear
dichroism are discussed.
Abstract: Some regularities of formation of a new structural
state of the thermoplastic polymers - gradually oriented (stretched)
state (GOS) are discussed. Transition into GOS is realized by the
graded oriented stretching - by action of inhomogeneous mechanical
field on the isotropic linear polymers or by zone stretching that is
implemented on a standard tensile-testing machine with using a
specially designed zone stretching device (ZSD). Both technical
approaches (especially zone stretching method) allows to manage the
such quantitative parameters of gradually oriented polymers as a
range of change in relative elongation/orientation degree, length of
this change and profile (linear, hyperbolic, parabolic, logarithmic,
etc.). The possibility of obtaining functionally graded materials
(FGMs) by graded orientation method is briefly discussed. Uniaxial
graded stretching method should be considered as an effective
technological solution to create polymer materials with a
predetermined gradient of physical properties.
Abstract: In this paper a real-time obstacle avoidance approach
for both autonomous and non-autonomous dynamical systems (DS) is
presented. In this approach the original dynamics of the controller
which allow us to determine safety margin can be modulated.
Different common types of DS increase the robot’s reactiveness in
the face of uncertainty in the localization of the obstacle especially
when robot moves very fast in changeable complex environments.
The method is validated by simulation and influence of different
autonomous and non-autonomous DS such as important
characteristics of limit cycles and unstable DS. Furthermore, the
position of different obstacles in complex environment is explained.
Finally, the verification of avoidance trajectories is described through
different parameters such as safety factor.
Abstract: In this paper, Bayesian online inference in models of
data series are constructed by change-points algorithm, which
separated the observed time series into independent series and study
the change and variation of the regime of the data with related
statistical characteristics. variation of statistical characteristics of time
series data often represent separated phenomena in the some
dynamical system, like a change in state of brain dynamical reflected
in EEG signal data measurement or a change in important regime of
data in many dynamical system. In this paper, prediction algorithm
for studying change point location in some time series data is
simulated. It is verified that pattern of proposed distribution of data
has important factor on simpler and smother fluctuation of hazard
rate parameter and also for better identification of change point
locations. Finally, the conditions of how the time series distribution
effect on factors in this approach are explained and validated with
different time series databases for some dynamical system.
Abstract: Performance of different filtering approaches depends
on modeling of dynamical system and algorithm structure. For
modeling and smoothing the data the evaluation of posterior
distribution in different filtering approach should be chosen carefully.
In this paper different filtering approaches like filter KALMAN,
EKF, UKF, EKS and smoother RTS is simulated in some trajectory
tracking of path and accuracy and limitation of these approaches are
explained. Then probability of model with different filters is
compered and finally the effect of the noise variance to estimation is
described with simulations results.
Abstract: This paper presents a novel statistical description of
the counterpoise effective length due to lightning surges, where the
(impulse) effective length had been obtained by means of regressive
formulas applied to the transient simulation results. The effective
length is described in terms of a statistical distribution function, from
which median, mean, variance, and other parameters of interest could
be readily obtained. The influence of lightning current amplitude,
lightning front duration, and soil resistivity on the effective length has
been accounted for, assuming statistical nature of these parameters. A
method for determining the optimal counterpoise length, in terms of
the statistical impulse effective length, is also presented. It is based on
estimating the number of dangerous events associated with lightning
strikes. Proposed statistical description and the associated method
provide valuable information which could aid the design engineer in
optimising physical lengths of counterpoises in different grounding
arrangements and soil resistivity situations.
Abstract: This paper presents an evolutionary algorithm for
solving multi-objective optimization problems-based artificial neural
network (ANN). The multi-objective evolutionary algorithm used in
this study is genetic algorithm while ANN used is radial basis
function network (RBFN). The proposed algorithm named memetic
elitist Pareto non-dominated sorting genetic algorithm-based RBFN
(MEPGAN). The proposed algorithm is implemented on medical
diseases problems. The experimental results indicate that the
proposed algorithm is viable, and provides an effective means to
design multi-objective RBFNs with good generalization capability
and compact network structure. This study shows that MEPGAN
generates RBFNs coming with an appropriate balance between
accuracy and simplicity, comparing to the other algorithms found in
literature.