Abstract: The thermo-mechanical behaviour of concrete energy
pile foundations with different single and double U-tube shapes
incorporated was analysed using the Comsol Multi-physics package.
For the analysis, a 3D numerical model in real scale of the concrete
pile and surrounding soil was simulated regarding actual operation of
ground heat exchangers (GHE) and the surrounding ambient
temperature. Based on initial ground temperature profile measured in
situ, tube inlet temperature was considered to range from 6oC to 0oC
(during the contraction process) over a 30-day period. Extra thermal
stresses and deformations were calculated during the simulations and
differences arising from the use of two different systems (single-tube
and double-tube) were analysed. The results revealed no significant
difference for extra thermal stresses at the centre of the pile in either
system. However, displacements over the pile length were found to
be up to 1.5-fold higher in the double-tube system than the singletube
system.
Abstract: This paper discusses about the findings of preliminary
survey on MATLAB software learning among power electronics
students. One of the main focuses of power electronics course is on
DC to DC boost convertors, because boost convertors are generally
used in different industrial and non industrial applications. Population
samples of this study were randomly selected final year bachelor of
electronics and electrical engineering students from University Tun
Hussein Onn Malaysia (UTHM).As per the results from the survey
questioner analysis, almost eighty percent students are facing
problem and difficulties in Dc to Dc boost convertors experimental
understanding without using MATLAB simulink package. As per
finding of this study it is clear that MATLAB play an effective and
efficient function for better understanding of boost convertors
experimental work among power electronics learners.
Abstract: This paper explains about the voltage output for DC to
DC boost converter between open loop, PID controller and fuzzy
logic controller through Matlab Simulink. Simulink input voltage was
set at 12V and the voltage reference was set at 24V. The analysis on
the deviation of voltage resulted that the difference between reference
voltage setting and the output voltage is always lower. Comparison
between open loop, PID and FLC shows that, the open loop circuit
having a bit higher on the deviation of voltage. The PID circuit
boosts for FLC has a lesser deviation of voltage and proved that it is
such a better performance on control the deviation of voltage during
the boost mode.
Abstract: There are pending discussions over the mapping of
country export potential in order to refocus export strategy of firms
and its evidence-based promotion by the Export Credit Agencies
(ECAs) and other permitted vehicles of governments.
In this paper we develop our version of an applied model that
offers “stepwise” elimination of unattractive markets. We modify and
calibrate the model for the particular features of the Czech Republic
and specific pilot cases where we apply an individual approach to
each sector.
Abstract: The connection between past travel experience and
tourists’ revisit behavioral intentions has not been widely explored
but the existing studies suggest a close relationship between them.
Destination image can equally be construed as having effects on the
attitudes of the tourists at the end of their actual visitation and the
satisfaction of a tourist with his or her travel experiences contributes
to a revisit intention towards a particular destination. With strong
marketing efforts, UAE is not only considered to be successful in
attracting foreign investors, but is becoming the most popular tourism
destination in the Arab region. UAE is seriously developing its
tourism image and taking serious initiatives to attract new or repeat
visitations from the international tourists. This study empirically
investigates the causal relationships between tourism destination
image, tourist satisfaction and revisit intention using UAE as a
contextual study setting. A very clear picture emerged which
provides a host country with potential implications for its tourism
industry practitioners, Department of Tourism and Commerce
Marketing and the travel agencies who act as the intermediaries
between the potential tourists and the hotel operators.
Abstract: This study offers a comprehensive review of the
research papers published in the field of cooling towers and gives an
insight into the latest developments of the natural draught cooling
towers. Different modeling, analysis and design techniques are
summarized and the challenges are discussed. The 118 references
included in this paper are mostly concentrated on the review of the
published papers after 2005. The present paper represents a complete
collection of the studies done for cooling towers and would give an
updated material for the researchers and design engineers in the field
of hyperbolic cooling towers.
Abstract: Through this paper we present a method for automatic
generation of ontological model from any data source using Model
Driven Architecture (MDA), this generation is dedicated to the
cooperation of the knowledge engineering and software engineering.
Indeed, reverse engineering of a data source generates a software
model (schema of data) that will undergo transformations to generate
the ontological model. This method uses the meta-models to validate
software and ontological models.
Abstract: This paper presents a study on Proportional Resonant
(PR) current control with additional PR harmonic compensators for
Grid Connected Photovoltaic (PV) Inverters. Both simulation and
experimental results will be presented. Testing was carried out on a
3kW Grid-Connected PV Inverter which was designed and
constructed for this research.
Abstract: Curcuma longa L. (Zingiberaceae), commonly known
as turmeric, has a long history of traditional uses for culinary
purposes as a spice and a food colorant. The present study aimed to
document the ethnobotanical knowledge about Curcuma longa, and
to assess the variation in the herbalists’ experience in Northeastern
Algeria. Data were collected using semi-structured questionnaires
and direct interviews with 30 herbalists. Ethnobotanical indices,
including the fidelity level (FL%), the relative frequency citation
(RFC), and use value (UV) were determined by quantitative methods.
Diversity in the level of knowledge was analyzed using univariate,
non-parametric, and multivariate statistical methods. Three main
categories of uses were recorded for C. longa: for food, for medicine,
and for cosmetic purposes. As a medicine, turmeric was used for the
treatment of gastrointestinal, dermatological, and hepatic diseases.
Medicinal and food uses were correlated with both forms of
preparation (rhizome and powder). The age group did not influence
the use. Multivariate analyses showed a significant variation in
traditional knowledge, associated with the use value, origin, quality,
and efficacy of the drug. The findings suggested that the geographical
origin of C. longa affected the use in Algeria.
Abstract: The use of information and communication
technologies such as computers, mobile phones and the Internet is
becoming prevalent in today’s world; and it is facilitating access to a
vast amount of data, services and applications for the improvement of
people’s lives. However, this prevalence of ICTs is hampered by the
problem of low income levels in developing countries to the point
where people cannot timeously replace or repair their ICT devices
when damaged or lost; and this problem serves as a motivation for
this study whose aim is to examine the perceptions of teachers on the
reliability of cellphones when used for teaching and learning
purposes. The research objectives unfolding this aim are of two
types: Objectives on the selection and design of theories and models,
and objectives on the empirical testing of these theories and models.
The first type of objectives is achieved using content analysis in an
extensive literature survey: and the second type of objectives is
achieved through a survey of high school teachers from the ILembe
and UMgungundlovu districts in the KwaZulu-Natal province of
South Africa. Data collected from this questionnaire based survey is
analysed in SPSS using descriptive statistics and Pearson correlations
after checking the reliability and validity of the questionnaires. The
main hypothesis driving this study is that there is a relationship
between the demographics and the attribution identity of teachers on
one hand, and their perceptions on the reliability of cellphones on the
other hand, as suggested by existing literature; except that attribution
identities are considered in this study under three angles: intention,
knowledge and ability, and action. The results of this study confirm
that the perceptions of teachers on the reliability of cellphones for
teaching and learning are affected by the school location of these
teachers, and by their perceptions on learners’ cellphones usage
intentions and actual use.
Abstract: The handwriting is a physical demonstration of a
complex cognitive process learnt by man since his childhood. People
with disabilities or suffering from various neurological diseases are
facing so many difficulties resulting from problems located at the
muscle stimuli (EMG) or signals from the brain (EEG) and which
arise at the stage of writing. The handwriting velocity of the same
writer or different writers varies according to different criteria: age,
attitude, mood, writing surface, etc. Therefore, it is interesting to
reconstruct an experimental basis records taking, as primary
reference, the writing speed for different writers which would allow
studying the global system during handwriting process. This paper
deals with a new approach of the handwriting system modeling based
on the velocity criterion through the concepts of artificial neural
networks, precisely the Radial Basis Functions (RBF) neural
networks. The obtained simulation results show a satisfactory
agreement between responses of the developed neural model and the
experimental data for various letters and forms then the efficiency of
the proposed approaches.
Abstract: At-site flood frequency analysis is used to estimate
flood quantiles when at-site record length is reasonably long. In
Australia, FLIKE software has been introduced for at-site flood
frequency analysis. The advantage of FLIKE is that, for a given
application, the user can compare a number of most commonly
adopted probability distributions and parameter estimation methods
relatively quickly using a windows interface. The new version of
FLIKE has been incorporated with the multiple Grubbs and Beck test
which can identify multiple numbers of potentially influential low
flows. This paper presents a case study considering six catchments in
eastern Australia which compares two outlier identification tests
(original Grubbs and Beck test and multiple Grubbs and Beck test)
and two commonly applied probability distributions (Generalized
Extreme Value (GEV) and Log Pearson type 3 (LP3)) using FLIKE
software. It has been found that the multiple Grubbs and Beck test
when used with LP3 distribution provides more accurate flood
quantile estimates than when LP3 distribution is used with the
original Grubbs and Beck test. Between these two methods, the
differences in flood quantile estimates have been found to be up to
61% for the six study catchments. It has also been found that GEV
distribution (with L moments) and LP3 distribution with the multiple
Grubbs and Beck test provide quite similar results in most of the
cases; however, a difference up to 38% has been noted for flood
quantiles for annual exceedance probability (AEP) of 1 in 100 for one
catchment. This finding needs to be confirmed with a greater number
of stations across other Australian states.
Abstract: A novel method to produce a fast high voltage solid
states switch using Insulated Gate Bipolar Transistors (IGBTs) is
presented for discharge-pumped gas lasers. The IGBTs are connected
in series to achieve a high voltage rating. An avalanche transistor is
used as the gate driver. The fast pulse generated by the avalanche
transistor quickly charges the large input capacitance of the IGBT,
resulting in a switch out of a fast high-voltage pulse. The switching
characteristic of fast-high voltage solid state switch has been estimated
in the multi-stage series-connected IGBT with the applied voltage of
several tens of kV. Electrical circuit diagram and the mythology of
fast-high voltage solid state switch as well as experimental results
obtained are presented.
Abstract: An investigation into the effect of countersunk depth,
plate thickness, countersunk angle and plate width on the stress
concentration around countersunk hole is carried out with the help of
finite element analysis. The variation of stress concentration with
respect to these parameters is studied for three types of loading viz.
uniformly distributed load, uniformly varying load and functionally
distributed load. The results of the finite element analysis are
interpreted and some conclusions are drawn. The distribution of
stress concentration around countersunk hole in isotropic plates
simply supported at all the edges is found similar and is independent
of loading. The maximum stress concentration also occurs at a
particular point irrespective of the loading conditions.
Abstract: Present study is aimed on the cutting process of circular
cross-section rods where the fracture is used to separate one rod
into two pieces. Incorporating the phenomenological ductile fracture
model into the explicit formulation of finite element method, the
process can be analyzed without the necessity of realizing too many
real experiments which could be expensive in case of repetitive
testing in different conditions. In the present paper, the steel AISI
1045 was examined and the tensile tests of smooth and notched
cylindrical bars were conducted together with biaxial testing of the
notched tube specimens to calibrate material constants of selected
phenomenological ductile fracture models. These were implemented
into the Abaqus/Explicit through user subroutine VUMAT and used
for cutting process simulation. As the calibration process is based
on variables which cannot be obtained directly from experiments,
numerical simulations of fracture tests are inevitable part of the
calibration. Finally, experiments regarding the cutting process were
carried out and predictive capability of selected fracture models is
discussed. Concluding remarks then make the summary of gained
experience both with the calibration and application of particular
ductile fracture criteria.
Abstract: Self-service technologies (SSTs) make an important
contribution to the daily life of people nowadays. However, the
introduction of SST does not lead to its usage. Thereby, this paper
was an attempt on discovery of the most preferred SST in the
customers’ point of view. To fulfill this aim, the Analytical Hierarchy
Process (AHP) was applied based on Saaty’s questionnaire which
was administered to the customers of e-banking services located in
Golestan providence, northern Iran. This study used qualitative
factors in association with the intention of consumers’ usage of SSTs
to rank three SSTs: ATM, mobile banking and internet banking. The
results showed that mobile banking get the highest weight in
consumers’ point of view. This research can be useful both for
managers and service providers and also for customers who intend to
use e-banking.
Abstract: This paper deals with the problem of automatic rule
generation for fuzzy systems design. The proposed approach is based
on hybrid artificial bee colony (ABC) optimization and weighted least
squares (LS) method and aims to find the structure and parameters of
fuzzy systems simultaneously. More precisely, two ABC based fuzzy
modeling strategies are presented and compared. The first strategy
uses global optimization to learn fuzzy models, the second one
hybridizes ABC and weighted least squares estimate method. The
performances of the proposed ABC and ABC-LS fuzzy modeling
strategies are evaluated on complex modeling problems and compared
to other advanced modeling methods.
Abstract: Drying behavior of blanched sweet potato in a cabinet
dryer using different five air temperatures (40-80°C) and ten sweet
potato varieties sliced to 5mm thickness were investigated. The
drying data were fitted to eight models. The Modified Henderson and
Pabis model gave the best fit to the experimental moisture ratio data
obtained during the drying of all the varieties while Newton (Lewis)
and Wang and Singh models gave the least fit. The values of Deff
obtained for Bophelo variety (1.27 x 10-9 to 1.77 x 10-9 m2/s) was
the least while that of S191 (1.93 x 10-9 to 2.47 x 10-9 m2/s) was the
highest which indicates that moisture diffusivity in sweet potato is
affected by the genetic factor. Activation energy values ranged from
0.27-6.54 kJ/mol. The lower activation energy indicates that drying
of sweet potato slices requires less energy and is hence a cost and
energy saving method. The drying behavior of blanched sweet potato
was investigated in a cabinet dryer. Drying time decreased
considerably with increase in hot air temperature. Out of the eight
models fitted, the Modified Henderson and Pabis model gave the best
fit to the experimental moisture ratio data on all the varieties while
Newton, Wang and Singh models gave the least. The lower activation
energy (0.27 - 6.54 kJ/mol) obtained indicates that drying of sweet
potato slices requires less energy and is hence a cost and energy
saving method.
Abstract: The postharvest quality management of tomatoes is
important to limit the amount of losses that occur due to deterioration
between harvest and consumption. This study was undertaken to
investigate the effects of pre- and postharvest integrated agrotechnologies,
involving greenhouse microclimate and postharvest
storage conditions, on the postharvest quality attributes of four
tomato cultivars. Tomato fruit firmness, colour (hue angle (h°) and
L* value), pH and total soluble solids for the cultivars Bona,
Star 9037, Star 9009 and Zeal, grown in a fan-pad evaporativelycooled
and an open-ended naturally-ventilated tunnel, were harvested
at the mature-green stage. The tomatoes were stored for 28 days
under cold storage conditions, with a temperature of 13°C and RH of
85%, and under ambient air conditions, with a temperature of 23±
2°C and RH of 52± 4%. This study has provided information on the
effect of integrated pre-harvest and postharvest agro-technologies,
involving greenhouse microclimate and postharvest storage
environment on the postharvest quality attributes of four of the
tomato cultivars in South Africa. NVT-grown tomatoes retained
better textural qualities, but ripened faster by changing from green to
red faster, although these were reduced under cold storage conditions.
FPVT-grown tomatoes had lower firmness, but ripened slowly with
higher colour attributes. With cold storage conditions, the firmness of
FPVT-grown tomatoes was maintained. Cultivar Bona firmness and
colour qualities depreciated the fastest, but it had higher TSS content
and lower pH values. Star 9009 and Star 9037 presented better
quality, by retaining higher firmness and ripening slowly, but they
had the lowest TSS contents and high pH values, especially
Star 9037. Cold storage improved the firmness of tomato cultivars
with poor textural quality and faster colour changes.
Abstract: In this paper, we introduce a generalized Chebyshev
collocation method (GCCM) based on the generalized Chebyshev
polynomials for solving stiff systems. For employing a technique
of the embedded Runge-Kutta method used in explicit schemes, the
property of the generalized Chebyshev polynomials is used, in which
the nodes for the higher degree polynomial are overlapped with those
for the lower degree polynomial. The constructed algorithm controls
both the error and the time step size simultaneously and further
the errors at each integration step are embedded in the algorithm
itself, which provides the efficiency of the computational cost. For
the assessment of the effectiveness, numerical results obtained by the
proposed method and the Radau IIA are presented and compared.