Abstract: A novel Active Flap System (AFS) has been developed
at DTU Wind Energy, as a result of a 3-year R&D project following
almost 10 years of innovative research in this field. The full scale AFS
comprises an active deformable trailing edge has been tested at the
unique rotating test facility at the Risø Campus of DTU Wind Energy
in Denmark. The design and instrumentation of the wing section and
the AFS are described. The general description and objectives of the
rotating test rig at the Risø campus of DTU are presented, along
with an overview of sensors on the setup and the test cases. The
post-processing of data is discussed and results of steady, flap step
and azimuth control flap cases are presented.
Abstract: The aim of this study was to investigate the
photocatalytic activity of polycrystalline phases of bismuth tungstate
of formula Bi2WO6. Polycrystalline samples were elaborated using a
coprecipitation technique followed by a calcination process at
different temperatures (300, 400, 600 and 900°C). The obtained
polycrystalline phases have been characterized by X-ray diffraction
(XRD), scanning electron microscopy (SEM), and transmission
electron microscopy (TEM). Crystal cell parameters and cell volume
depend on elaboration temperature. High-resolution electron
microscopy images and image simulations, associated with X-ray
diffraction data, allowed confirming the lattices and space groups
Pca21. The photocatalytic activity of the as-prepared samples was
studied by irradiating aqueous solutions of Rhodamine B, associated
with Bi2WO6 additives having variable crystallite sizes. The
photocatalytic activity of such bismuth tungstates increased as the
crystallite sizes decreased. The high specific area of the
photocatalytic particles obtained at 300°C seems to condition the
degradation kinetics of RhB.
Abstract: In this paper, temperature extremes are forecast by
employing the block maxima method of the Generalized extreme
value(GEV) distribution to analyse temperature data from the
Cameroon Development Corporation (C.D.C). By considering two sets
of data (Raw data and simulated data) and two (stationary and
non-stationary) models of the GEV distribution, return levels analysis
is carried out and it was found that in the stationary model, the
return values are constant over time with the raw data while in the
simulated data, the return values show an increasing trend but with
an upper bound. In the non-stationary model, the return levels of
both the raw data and simulated data show an increasing trend but
with an upper bound. This clearly shows that temperatures in the
tropics even-though show a sign of increasing in the future, there
is a maximum temperature at which there is no exceedence. The
results of this paper are very vital in Agricultural and Environmental
research.
Abstract: The purpose of this paper is to examine the effects and
relationship of stress and social support towards the quality of life
among flood victims in Malaysia. A total of 764 respondents took
part in the survey via convenience sampling. The Depression,
Anxiety and Stress scale (DASS) was utilized to measure stress while
The Multidimensional Scale of Perceived Social Support was used to
measure social support. To measure quality of life, the combination
of WHO Quality of Life – BREF (WHOQOL-BREF) and The Impact
of Event Scale – Revised (IES-R) were utilized. The findings of this
study indicate that there were significant correlations between
variables in the study. The findings showed a significant negative
relation between stress and quality of life; and significant positive
correlations between support from family as well as support from
friends with quality of life. Stress and support from family were
found to be significant predictors that influence the quality of life
among flood victims.
Abstract: Currently, planners try to have more green travel
options to decrease economic, social and environmental problems.
Therefore, this study tries to find significant urban travel factors to be
used to increase the usage of alternative urban travel modes. This
paper attempts to identify the relationship between prominent urban
mobility indicators and daily trips by public transport in 30 cities
from various parts of the world. Different travel modes,
infrastructures and cost indicators were evaluated in this research as
mobility indicators. The results of multi-linear regression analysis
indicate that there is a significant relationship between mobility
indicators and the daily usage of public transport.
Abstract: Review of studies carried out on the use of bagasse
ash for the improvement of deficient soils in Nigeria, with emphasis
on lateritic and black cotton soils is presented. Although, the bagasse
ash is mostly used as additive to the conventional soil stabilizers
(cement and lime), the studies generally showed improvement in the
geotechnical properties of the soils, either modified or stabilized with
the ash. This showed the potentials of using this agricultural waste
(bagasse ash) in the improvement of geotechnical properties of
deficient soils, thus suggesting that using this material at large scale
level in geotechnical engineering practice could help in the provision
of stable and durable structures, reduce cost of soil improvement and
also reduces environmental nuisance caused by the unused waste in
Nigeria.
Abstract: Due to the interference effects, the intrinsic
aerodynamic parameters obtained from the individual component
testing are always fundamentally different than those obtained for
complete model testing. Consideration and limitation for such testing
need to be taken into account in any design work related to the
component buildup method. In this paper, the scaled model of a
straight rectangular canard of a hybrid buoyant aircraft is tested at 50
m/s in IIUM-LSWT (Low Speed Wind Tunnel). Model and its
attachment with the balance are kept rigid to have results free from
the aeroelastic distortion. Based on the velocity profile of the test
section’s floor; the height of the model is kept equal to the
corresponding boundary layer displacement. Balance measurements
provide valuable but limited information of overall aerodynamic
behavior of the model. Zero lift coefficient is obtained at -2.2o and
the corresponding drag coefficient was found to be less than that at
zero angle of attack. As a part of the validation of low fidelity tool,
plot of lift coefficient plot was verified by the experimental data and
except the value of zero lift coefficients, the overall trend has under
predicted the lift coefficient. Based on this comparative study, a
correction factor of 1.36 is proposed for lift curve slope obtained
from the panel method.
Abstract: Multiphase Induction Machine (IM) is normally
controlled using rotor field oriented vector control. Under phase(s)
loss, the machine currents can be optimally controlled to satisfy
certain optimization criteria. In this paper we discuss the performance
of double manifold sliding mode observer (DM-SMO) in Sensorless
control of multiphase induction machine under unsymmetrical
condition (one phase loss). This observer is developed using the IM
model in the stationary reference frame. DM-SMO is constructed by
adding extra feedback term to conventional single mode sliding mode
observer (SM-SMO) which proposed in many literature. This leads to
a fully convergent observer that also yields an accurate estimate of
the speed and stator currents. It will be shown by the simulation
results that the estimated speed and currents by the method are very
well and error between real and estimated quantities is negligible.
Also parameter sensitivity analysis shows that this method is rather
robust against parameter variation.
Abstract: The purpose of this research was to investigate the
creep behaviour of the heterogeneous Timber-UHPFRC beams. New
developments have been done to further improve the structural
performance, such as strengthening of the timber (glulam) beam by
bonding composite material combine with an ultra-high performance
fibre reinforced concrete (UHPFRC) internally reinforced with or
without carbon fibre reinforced polymer (CFRP) bars. However, in
the design of wooden structures, in addition to the criteria of
strengthening and stiffness, deformability due to the creep of wood,
especially in horizontal elements, is also a design criterion. Glulam,
UHPFRC and CFRP may be an interesting composite mix to respond
to the issue of creep behaviour of composite structures made of
different materials with different rheological properties. In this paper,
we describe an experimental and analytical investigation of the creep
performance of the glulam-UHPFRC-CFRP beams assembled by
bonding. The experimental investigations creep behaviour was
conducted for different environments: in- and outside under constant
loading for approximately a year. The measured results are compared
with numerical ones obtained by an analytical model. This model was
developed to predict the creep response of the glulam-UHPFRCCFRP
beams based on the creep characteristics of the individual
components. The results show that heterogeneous glulam-UHPFRC
beams provide an improvement in both the strengthening and
stiffness, and can also effectively reduce the creep deflection of
wooden beams.
Abstract: Chitosan polyacrylic acid composite membranes were
prepared by a bulk polymerization method in presence of N, N'-
methylene bisacrylamide (crosslinker) and ammonium persulphate as
initiator. Membranes prepared from this copolymer in presence and
absence of Ag nanoparticles were characterized by measuring
mechanical and physical properties, water up-take and antibacterial
properties. The results obtained indicated that the prepared
membranes have antibacterial properties which increase with adding
Ag nanoparticles.
Abstract: In this paper we present the design of an optical
device based on a Herriott multi-pass cell fabricated on a small sized
acrylic slab for heat flux measurements using the deflection of a laser
beam propagating inside the cell. The beam deflection is produced by
the heat flux conducted to the acrylic slab due to a gradient in the
refractive index. The use of a long path cell as the sensitive element
in this measurement device, gives the possibility of high sensitivity
within a small size device. We present the optical design as well as
some experimental results in order to validate the device’s operation
principle.
Abstract: The main idea of this work is to investigate the effect
of knitted fabrics characteristics on moisture management properties.
Wetting and transport properties of single jersey, Rib 1&1 and
English Rib fabrics made out of cotton and blended Cotton/Polyester
yarns were studied. The dynamic water sorption of fabrics was
investigated under same isothermal and terrestrial conditions at
20±2°C-65±4% by using the Moisture Management Tester (MMT)
which can be used to quantitatively measure liquid moisture transfer
in one step in a fabric in multidirections: Absorption rate, moisture
absorbing time of the fabric's inner and outer surfaces, one-way
transportation capability, the spreading/drying rate, the speed of
liquid moisture spreading on fabric's inner and outer surfaces are
measured, recorded and discussed. The results show that fabric’s
composition and knit’s structure have a significant influence on those
phenomena.
Abstract: The study focused on the analysis of the Adjusted
Rorschach Comprehensive System’s responses. The objective of this
study is to analyse the participants’ response rate of the Adjusted
Rorschach Comprehensive System with regards to critical
psychology approach. The use of critical psychology theory in this
study was crucial because it responds to the current inadequate
western theory or practice in the field of psychology. The study
adopted a qualitative approach and a case study design. The study
was grounded on interpretivist paradigm. The sample size comprised
six learners (three boys and three girls, aged of 14 years) from
historically disadvantaged school in the Western Cape, South Africa.
The Adjusted Rorschach Comprehensive System (ARCS)
administration procedure, biographical information, semi-structured
interviews, and observation were used to collect data. Data was
analysed using thematic framework. The study found out that, factors
that increased the response rates during the administration of ARCS
were, language, seating arrangement, drawing, viewing, and
describing. The study recommended that, psychological test
designers take into consideration the philosophy or worldviews of the
local people for whom the test is designed to minimize low response
rates.
Abstract: The Adaptive Line Enhancer (ALE) is widely used for
enhancing narrowband signals corrupted by broadband noise. In this
paper, we propose novel ALE methods to improve the enhancing
capability. The proposed methods are motivated by the fact that the
output of the ALE is a fine estimate of the desired narrowband signal
with the broadband noise component suppressed. The proposed
methods preprocess the input signal using ALE filter to regenerate a
finer input signal. Thus the proposed ALE is driven by the input signal
with higher signal-to-noise ratio (SNR). The analysis and simulation
results are presented to demonstrate that the proposed ALE has better
performance than conventional ALE’s.
Abstract: This paper explores and provides substantiated
evidence on the usage patterns of Information and Communication
Technologies (ICTs) by female users at Vhembe District in Limpopo-
Province, South Africa. The study presents a comprehensive picture
on the usage of ICTs from female users’ perspective. The
significance of this study stems from the need to assess the role,
relevance and usage patterns of ICTs such as smartphones,
computers, laptops, and iPods, the internet and social networking
sites among females following the developments of new media
technologies in society. The objective of the study is to investigate
the usability and accessibility of ICTs to empower female users in
South Africa. The study used quantitative and qualitative research
methods to determine the major ideas, perceptions and usage patterns
of ICTs by users. Data collection involved the use of structured selfadministered
questionnaire from two groups of respondents who
participated in this study. Thus, (n=50) female students at the
University of Venda provided their ideas and perceptions about the
usefulness and usage patterns of ICTs such as smartphones, the
Internet and computers at the university level, whereas, the second
group were (n=50) learners from Makhado Comprehensive School
who provided their perceptions and ideas about the use of ICTs at the
high school level. The researcher also noted that the findings of the
study were useful as a guideline and model for ICT intervention that
could work as an empowerment to women in South Africa. It was
observed that the central purpose of ICTs among female users was to
search for information regarding assignment writing, conducting
research, dating, exchanging ideas and networking with friends and
relatives. This was demonstrated by a high number of females who
used ICTs for e-learning (62%) and social purposes (85%).
Therefore, the study revealed that most females used ICTs for social
purposes and accessing the internet rather than for entertainment, a
gesture that provides an opportune space to empower rural women in
South Africa.
Abstract: For a rigid body sliding on a rough surface, a range of
uncertainty or non-uniqueness of solution could be found, which is
termed: Painlevé paradox. Painlevé paradox is the reason of a wide
range of bouncing motion, observed during sliding of robotic
manipulators on rough surfaces. In this research work, the existence
of the paradox zone during the sliding motion of a two-link (P-R)
robotic manipulator with a unilateral constraint is investigated.
Parametric study is performed to investigate the effect of friction,
link-length ratio, total height and link-mass ratio on the paradox zone.
Abstract: Current transformers are an integral part of power
system because it provides a proportional safe amount of current for
protection and measurement applications. However, when the power
system experiences an abnormal situation leading to huge current
flow, then this huge current is proportionally injected to the
protection and metering circuit. Since the protection and metering
equipment’s are designed to withstand only certain amount of current
with respect to time, these high currents pose a risk to man and
equipment. Therefore, during such instances, the CT saturation
characteristics have a huge influence on the safety of both man and
equipment and on the reliability of the protection and metering
system. This paper shows the effect of burden on the Accuracy Limiting
factor/ Instrument security factor of current transformers and the
change in saturation characteristics of the CT’s. The response of the
CT to varying levels of overcurrent at different connected burden will
be captured using the data acquisition software LabVIEW. Analysis
is done on the real time data gathered using LabVIEW. Variation of
current transformer saturation characteristics with changes in burden
will be discussed.
Abstract: Networked environments which provide platforms for
business organizations are configured in different forms depending
on many factors including life time, member characteristics,
communication structure, and business objectives, among others.
With continuing advances in digital technologies the distance has
become a less barrier for business minded collaboration among
organizations. With the need and ease to make business collaborate
nowadays organizations are sometimes forced to co-work with others
that are either unknown or less known to them in terms of history and
performance. A promising approach for sustaining established
collaboration has been establishment of trust relationship among
organizations based on assessed trustworthiness for each participating
organization. It has been stated in research that trust in organization is
dynamic and thus assessment of trust level must address such
dynamic nature. This paper assesses relevant aspects of trust and
applies the assessed concepts to propose a semi-automated system for
the management of Sustainability and Evolution of trust in
organizations participating in specific objective in a networked
organizations environment.
Abstract: To decrease the grating scale thermal expansion error,
a novel method which based on multiple temperature detection is
proposed. Several temperature sensors are installed on the grating
scale and the temperatures of these sensors are recorded. The
temperatures of every point on the grating scale are calculated by
interpolating between adjacent sensors. According to the thermal
expansion principle, the grating scale thermal expansion error model
can be established by doing the integral for the variations of position
and temperature. A novel compensation method is proposed in this
paper. By applying the established error model, the grating scale
thermal expansion error is decreased by 90% compared with no
compensation. The residual positioning error of the grating scale is
less than 15μm/10m and the accuracy of the machine tool is
significant improved.
Abstract: Wire Electric Discharge Machining (WEDM) is
thermal machining process capable of machining very hard
electrically conductive material irrespective of their hardness.
WEDM is being widely used to machine micro scale parts with the
high dimensional accuracy and surface finish. The objective of this
paper is to optimize the process parameters of wire EDM to fabricate
the micro channels and to calculate the surface finish and material
removal rate of micro channels fabricated using wire EDM. The
material used is aluminum 6061 alloy. The experiments were
performed using CNC wire cut electric discharge machine. The effect
of various parameters of WEDM like pulse on time (TON) with the
levels (100, 150, 200), pulse off time (TOFF) with the levels (25, 35,
45) and current (IP) with the levels (105, 110, 115) were investigated
to study the effect on output parameter i.e. Surface Roughness and
Material Removal Rate (MRR). Each experiment was conducted
under different conditions of pulse on time, pulse off time and peak
current. For material removal rate, TON and Ip
were the most significant process parameter. MRR increases with the increase in
TON and Ip and decreases with the increase in TOFF. For surface
roughness, TON and Ip have the maximum effect and TOFF was found
out to be less effective.