Abstract: To achieve reliable welds with minimum distortion for
the fabrication of components in aerospace industry laser beam
welding is attempted. Laser welding can provide a significant benefit
for the welding of Titanium and Aluminium thin sheet alloys of its
precision and rapid processing capability. For laser welding, pulse
shape, energy, duration, repetition rate and peak power are the most
important parameters that influence directly the quality of welds. In
this experimental work for joining 1mm thick TI6AL4V and AA2024
alloy and JK600 Nd:YAG pulsed laser units used. The distortions at
different welding power and speed of titanium and aluminium thin
sheet alloys are investigated. Test results reveal that increase in
welding speed increases distortion in weldment
Abstract: This paper presents small signal stability study carried
over the 140-Bus, 31-Machine, 5-Area MEPE system and validated
on free and open source software: PSAT. Well-established linearalgebra
analysis, eigenvalue analysis, is employed to determine the
small signal dynamic behavior of test system. The aspects of local
and interarea oscillations which may affect the operation and
behavior of power system are analyzed. Eigenvalue analysis is carried
out to investigate the small signal behavior of test system and the
participation factors have been determined to identify the
participation of the states in the variation of different mode shapes.
Also, the variations in oscillatory modes are presented to observe the
damping performance of the test system.
Abstract: The 3D body movement signals captured during
human-human conversation include clues not only to the content of
people’s communication but also to their culture and personality.
This paper is concerned with automatic extraction of this information
from body movement signals. For the purpose of this research, we
collected a novel corpus from 27 subjects, arranged them into groups
according to their culture. We arranged each group into pairs and
each pair communicated with each other about different topics.
A state-of-art recognition system is applied to the problems of
person, culture, and topic recognition. We borrowed modeling,
classification, and normalization techniques from speech recognition.
We used Gaussian Mixture Modeling (GMM) as the main technique
for building our three systems, obtaining 77.78%, 55.47%, and
39.06% from the person, culture, and topic recognition systems
respectively. In addition, we combined the above GMM systems with
Support Vector Machines (SVM) to obtain 85.42%, 62.50%, and
40.63% accuracy for person, culture, and topic recognition
respectively.
Although direct comparison among these three recognition
systems is difficult, it seems that our person recognition system
performs best for both GMM and GMM-SVM, suggesting that intersubject
differences (i.e. subject’s personality traits) are a major
source of variation. When removing these traits from culture and
topic recognition systems using the Nuisance Attribute Projection
(NAP) and the Intersession Variability Compensation (ISVC)
techniques, we obtained 73.44% and 46.09% accuracy from culture
and topic recognition systems respectively.
Abstract: The aim of this study is to evaluate the effects of the
laser and partial vibration stimulation on the mice tibia with
morphological characteristics. Twenty female C57BL/6 mice (12
weeks old) were used for the experiment. The study was carried out on
four groups of animals each consisting of five mice. Four groups of
mice were ovariectomized. Animals were scanned at 0 and 2 weeks
after ovariectomy by using micro computed tomography to estimate
morphological characteristics of tibial trabecular bone. Morphological
analysis showed that structural parameters of multi-stimuli group
appear significantly better phase in BV/TV, BS/BV, Tb.Th, Tb.N,
Tb.Sp, and Tb.pf than single stimulation groups. However, single
stimulation groups didn’t show significant effect on tibia with Sham
group. This study suggests that multi-stimuli may restrain the change
as the degenerate phase on osteoporosis in the mice tibia.
Abstract: The concept of urban transformation came about
through interventions aimed at bringing socially and economically
problematic areas of cities into use. The issue of urban transformation
arose frequently during the post-2000 period in particular, and legal
regulations on this matter were also developed in Turkey. Urban
transformation project would be a focal point for the formation of the
city in the near future. Izmir, which is third largest city of Turkey, is
an important trade and port city. But, assessment of the current
situation shows that, the majority of existing residential areas was
formed with squatters and unplanned settlements in Izmir city center.
Therefore an important part of these areas have significant problems
in terms of the quality of life, safety and environmental quality. In
this study, the central policies in Turkey and local policies in Đzmir
about urban transformation will be considered. In addition, urban
renewal projects that are being implemented in Izmir were discussed
and suggestions will be developed in accordance with this policy.
Abstract: These days, the field of tissue engineering is getting
serious attention due to its usefulness. Bone tissue engineering helps
to address and sort-out the critical sized and non-healing orthopedic
problems by the creation of manmade bone tissue. We will design
and validate an efficient numerical model, which will simulate the
effective diffusivity in bone tissue engineering. Our numerical model
will be based on the finite element analysis of the diffusion-reaction
equations. It will have the ability to optimize the diffusivity, even
at multi-scale, with the variation of time. It will also have a special
feature “parametric sweep”, with which we will be able to predict
the oxygen, glucose and cell density dynamics, more accurately. We
will fix these problems by modifying the governing equations, by
selecting appropriate spatio-temporal finite element schemes and by
transient analysis.
Abstract: Stator elements «Vane diffuser + crossover + return
channel» of stages with different specific speed were investigated by
CFD calculations. The regime parameter was introduced to present
efficiency and loss coefficient performance of all elements together.
Flow structure demonstrated advantages and disadvantages of design.
Flow separation in crossovers was eliminated by its shape
modification. Efficiency increased visibly. Calculated CFD
performances are in acceptable correlation with predicted ones by
engineering design method. The information obtained is useful for
design method better calibration.
Abstract: A compact UWB planar antenna fed with a
microstrip-line is proposed. The new design consist of a rectangular
patch with symmetric l-shaped slots and fed by 50 Ω microstrip
transmission line and a reduced ground-plane which have a periodic
slots with an overall size of 47 mm x 20 mm. It is intended to be used
in wireless applications that cover the ultra-wideband (UWB)
frequency band. A wider impedance bandwidth of around 116.5%
(1.875 – 7.115 GHz) with stable radiation pattern is achieved. The
proposed antenna has excellent characteristics, low profile and costeffective
compared to existing UWB antennas. The UWB antenna is
designed and analyzed using CST Microwave Studio in transient
mode to verify antenna parameters improvements.
Abstract: Waste silicon carbide (waste SiC) filled high-density
polyethylene (HDPE) with and without surface modifiers were
studied. Two types of surface modifiers namely; high-density
polyethylene-grafted-maleic anhydride (HDPE-g-MA) and 3-aminopropyltriethoxysilane have been used in this study. The
composites were produced using a two roll mill, extruder and shaped
in a hydraulic compression molding machine. The mechanical
properties of polymer composites such as flexural strength and
modulus, impact strength, tensile strength, stiffness and hardness
were investigated over a range of compositions. It was found that,
flexural strength and modulus, tensile modulus and hardness
increased, whereas impact strength and tensile strength decreased
with the increasing in filler contents, compared to the neat HDPE. At
similar filler content, the effect of both surface modifiers increased
flexural modulus, impact strength, tensile strength and stiffness but
reduced the flexural strength. Morphological investigation using
SEM revealed that the improvement in mechanical properties was
due to enhancement of the interfacial adhesion between waste SiC
and HDPE.
Abstract: Logistics processes of perishable food in the supply
chain include the distribution activities and the real time temperature
monitoring to fulfil the cold chain requirements. The paper presents
the use of RFID (Radio Frequency Identification) technology as an
identification tool of receiving and shipping activities in the cold
store. At the same time, the use of RFID data loggers with
temperature sensors is presented to observe and store the
temperatures for the purpose of analyzing the processes and having
the history data available for traceability purposes and efficient recall
management.
Abstract: Modelling of the earth's surface and evaluation of
urban environment, with 3D models, is an important research topic.
New stereo capabilities of high resolution optical satellites images,
such as the tri-stereo mode of Pleiades, combined with new image
matching algorithms, are now available and can be applied in urban
area analysis. In addition, photogrammetry software packages gained
new, more efficient matching algorithms, such as SGM, as well as
improved filters to deal with shadow areas, can achieve more dense
and more precise results.
This paper describes a comparison between 3D data extracted
from tri-stereo and dual stereo satellite images, combined with pixel
based matching and Wallis filter. The aim was to improve the
accuracy of 3D models especially in urban areas, in order to assess if
satellite images are appropriate for a rapid evaluation of urban
environments.
The results showed that 3D models achieved by Pleiades tri-stereo
outperformed, both in terms of accuracy and detail, the result
obtained from a Geo-eye pair. The assessment was made with
reference digital surface models derived from high resolution aerial
photography. This could mean that tri-stereo images can be
successfully used for the proposed urban change analyses.
Abstract: Solar energy is a good option among renewable
energy resources due to its easy availability and abundance. The
simplest and most efficient way to utilize solar energy is to convert it
into thermal energy and this can be done with the help of solar
collectors. The thermal performance of such collectors is poor due to
less heat transfer from the collector surface to air. In this work,
experimental investigations of single pass solar air heater having
triangular duct and provided with roughness element on the underside
of the absorber plate. V-shaped ribs are used for investigation having
three different values of relative roughness pitch (p/e) ranges from 4-
16 for a fixed value of angle of attack (α), relative roughness height
(e/Dh) and a relative gap distance (d/x) values are 60°, 0.044 and 0.60
respectively. Result shows that considerable augmentation in heat
transfer has been obtained by providing roughness.
Abstract: The use OF adhesive anchors for wooden constructions is an efficient technology to connect and design timber members in new timber structures and to rehabilitate the damaged structural members of historical buildings. Due to the lack of standard regulation in this specific area of structural design, designers’ choices are still supported by test analysis that enables knowledge, and the prediction, of the structural behaviour of glued in rod joints. The paper outlines an experimental research activity aimed at identifying the tensile resistance capacity of several new adhesive joint prototypes made of epoxy resin, steel bar and timber, Oak and Douglas Fir species. The development of new adhesive connectors has been carried out by using epoxy to glue stainless steel bars into pre-drilled holes, characterised by smooth and rough internal surfaces, in timber samples. The realization of a threaded contact surface using a specific drill bit has led to an improved bond between wood and epoxy. The applied changes have also reduced the cost of the joints’ production. The paper presents the results of this parametric analysis and a Finite Element analysis that enables identification and study of the internal stress distribution in the proposed adhesive anchors.
Abstract: This study concerned the dynamic behavior of the
wind turbine rotor. Before all we have studied the loads applied to the
rotor, which allows the knowledge their effect on the fatigue, also
studied the rotor with longitudinal crack in order to determine stress,
strain and displacement. Firstly we compared the first six modes
shapes between cracking and uncracking of HAWT rotor. Secondly
we show show evolution of first six natural frequencies with
longitudinal crack propagation. Finally we conclude that the residual
change in the natural frequencies can be used as in shaft crack
diagnosis predictive maintenance.
Abstract: In this paper we describe one critical research
program within a complex, ongoing multi-year project (2010 to 2014
inclusive) with the overall goal to improve the learning outcomes for
first year undergraduate commerce/business students within an
Information Systems (IS) subject with very large enrolment. The
single research program described in this paper is the analysis of
student attitudes and decision making in relation to the availability of
formative assessment feedback via Web-based real time conferencing
and document exchange software (Adobe Connect). The formative
assessment feedback between teaching staff and students is in respect
of an authentic problem-based, team-completed assignment. The
analysis of student attitudes and decision making is investigated via
both qualitative (firstly) and quantitative (secondly) application of the
Theory of Planned Behavior (TPB) with a two statistically-significant
and separate trial samples of the enrolled students. The initial
qualitative TPB investigation revealed that perceived self-efficacy,
improved time-management, and lecturer-student relationship
building were the major factors in shaping an overall favorable
student attitude to online feedback, whilst some students expressed
valid concerns with perceived control limitations identified within the
online feedback protocols. The subsequent quantitative TPB
investigation then confirmed that attitude towards usage, subjective
norms surrounding usage, and perceived behavioral control of usage
were all significant in shaping student intention to use the online
feedback protocol, with these three variables explaining 63 percent of
the variance in the behavioral intention to use the online feedback
protocol. The identification in this research of perceived behavioral
control as a significant determinant in student usage of a specific
technology component within a virtual learning environment (VLE)
suggests that VLEs could now be viewed not as a single, atomic
entity, but as a spectrum of technology offerings ranging from the
mature and simple (e.g., email, Web downloads) to the cutting-edge
and challenging (e.g., Web conferencing and real-time document
exchange). That is, that all VLEs should not be considered the same.
The results of this research suggest that tertiary students have the
technological sophistication to assess a VLE in this more selective
manner.
Abstract: The design and plantwide control of an integrated
plant where the endothermic 1,4-butanediol dehydrogenation and the
exothermic furfural hydrogenation is simultaneously performed in a
single reactor is studied. The reactions can be carried out in an
adiabatic reactor using small hydrogen excess and with reduced
parameter sensitivity. The plant is robust and flexible enough to
allow different production rates of γ-butyrolactone and 2-methyl
furan, keeping high product purities. Rigorous steady state and
dynamic simulations performed in AspenPlus and AspenDynamics to
support the conclusions.
Abstract: Bio-composites derived from plant fiber and/or bioderived
polymer, are likely more ecofriendly and demonstrate
competitive performance with petroleum based composites. In this
research, the bio phenol-formaldehyde (bio-PF) was used as a matrix
and oil palm empty fruit bunch fiber (EFB) as reinforcement. The
matrix was synthesized via liquefaction and condensation to enhance
the combination of phenol and formaldehyde, during the process.
Then, the bio-PF was mixed with different percentage of EFB (5%,
10%, 15% and 20%) and molded at 180oC. The samples that viewed
under scanning electron microscopy (SEM) showed an excellent
wettability and interaction between EFB and matrix. Samples of 10%
EFB gave the optimum properties of impact and hardness meanwhile
sample 15% of EFB gave the highest reading of flexural modulus
(MOE) and flexural strength (MOR). For thermal stability analysis, it
was found that the weight loss and the activation energy (Ea) of the
bio-composites samples were decreased as the filler content
increased.
Abstract: Eucalyptus species are well reputed for their
traditional use in Asia as well as in other parts of the world; therefore,
the present study was designed to investigate the antimicrobial and
antioxidant activities associated with essential oils from different
Eucalyptus species. Essential oils from the leaves of six Eucalyptus
species, including: Eucalyptus woodwardi, Eucalyptus stricklandii,
Eucalyptus salubris, Eucalyptus sargentii, Eucalyptus torquata and
Eucalyptus wandoo were separated by hydrodistillation and dried
over anhydrous sodium sulphate. DPPH, ferric reducing antioxidant
power, and hydroxyl radical scavenging activity assays were carried
out to evaluate the antioxidant potential of the oils. The results
indicate that examined oils exhibit substantial antioxidant activities
relative to ascorbic acid. Previously, these oils were evaluated for
their antimicrobial activities, against wide range of bacterial and
fungal strains, and they were shown to possess significant
antimicrobial activities. In this study, further investigation into the
growth kinetics of oil-treated microbial cultures was conducted. The
results clearly demonstrate that the microbial growth was markedly
inhibited when treated with sub-MIC concentrations of the oils.
Taken together, the results obtained indicate a high potential of the
examined essential oils as bioactive oils, for nutraceutical and
medical applications, possessing significant antioxidant and anti
microbial activities.
Abstract: A Motzkin shift is a mathematical model for constraints
on genetic sequences. In terms of the theory of symbolic dynamics,
the Motzkin shift is nonsofic, and therefore, we cannot use the Perron-
Frobenius theory to calculate its topological entropy. The Motzkin
shift M(M,N) which comes from language theory, is defined to be the
shift system over an alphabet A that consists of N negative symbols,
N positive symbols and M neutral symbols. For an x in the full shift,
x will be in the Motzkin subshift M(M,N) if and only if every finite
block appearing in x has a non-zero reduced form. Therefore, the
constraint for x cannot be bounded in length. K. Inoue has shown that
the entropy of the Motzkin shift M(M,N) is log(M + N + 1). In this
paper, a new direct method of calculating the topological entropy of
the Motzkin shift is given without any measure theoretical discussion.
Abstract: In this paper, a new trend for improvement in semianalytical
method based on scale boundaries in order to solve the 2D
elastodynamic problems is provided. In this regard, only the
boundaries of the problem domain discretization are by specific subparametric
elements. Mapping functions are uses as a class of higherorder
Lagrange polynomials, special shape functions, Gauss-Lobatto-
Legendre numerical integration, and the integral form of the weighted
residual method, the matrix is diagonal coefficients in the equations
of elastodynamic issues. Differences between study conducted and
prior research in this paper is in geometry production procedure of
the interpolation function and integration of the different is selected.
Validity and accuracy of the present method are fully demonstrated
through two benchmark problems which are successfully modeled
using a few numbers of DOFs. The numerical results agree very well
with the analytical solutions and the results from other numerical
methods.