Abstract: This paper presents a model for a modified T-junction
device for microspheres generation. The numerical model is
developed using a commercial software package: COMSOL
Multiphysics. In order to test the accuracy of the numerical model,
multiple variables, such as the flow rate of cross-flow, fluid properties,
structure, and geometry of the microdevice are applied. The results
from the model are compared with the experimental results in the
diameter of the microsphere generated. The comparison shows a good
agreement. Therefore the model is useful in further optimization of the
device and feedback control of microsphere generation if any.
Abstract: The capability of exploiting the electronic charge and
spin properties simultaneously in a single material has made diluted
magnetic semiconductors (DMS) remarkable in the field of
spintronics. We report the designing of DMS based on zinc-blend
ZnO doped with Cr impurity. The full potential linearized augmented
plane wave plus local orbital FP-L(APW+lo) method in density
functional theory (DFT) has been adapted to carry out these
investigations. For treatment of exchange and correlation energy,
generalized gradient approximations have been used. Introducing Cr
atoms in the matrix of ZnO has induced strong magnetic moment
with ferromagnetic ordering at stable ground state. Cr:ZnO was found
to favor the short range magnetic interaction that
reflect tendency of Cr clustering. The electronic structure of ZnO is
strongly influenced in the presence of Cr impurity atoms where
impurity bands appear in the band gap.
Abstract: This study investigates the suitability of using plastic,
such as polyethylene terephthalate (PET), as a partial replacement of
natural coarse and fine aggregates (for example, brick chips and
natural sand) to produce lightweight concrete for load bearing
structural members. The plastic coarse aggregate (PCA) and plastic
fine aggregate (PFA) were produced from melted polyethylene
terephthalate (PET) bottles. Tests were conducted using three
different water–cement (w/c) ratios, such as 0.42, 0.48, and 0.57,
where PCA and PFA were used as 50% replacement of coarse and
fine aggregate respectively. Fresh and hardened properties of
concrete have been compared for natural aggregate concrete (NAC),
PCA concrete (PCC) and PFA concrete (PFC). The compressive
strength of concrete at 28 days varied with the water–cement ratio for
both the PCC and PFC. Between PCC and PFC, PFA concrete
showed the highest compressive strength (23.7 MPa) at 0.42 w/c ratio
and also the lowest compressive strength (13.7 MPa) at 0.57 w/c
ratio. Significant reduction in concrete density was mostly observed
for PCC samples, ranging between 1977–1924 kg/m³. With the
increase in water–cement ratio PCC achieved higher workability
compare to both NAC and PFC. It was found that both the PCA and
PFA contained concrete achieved the required compressive strength
to be used for structural purpose as partial replacement of the natural
aggregate; but to obtain the desired lower density as lightweight
concrete the PCA is most suited.
Abstract: The quality and condition of perishable products
delivered to the market and their subsequent selling prices are
directly affected by the care taken during harvesting and handling.
Mechanical injury, in fact, occurs at all stages, from pre-harvest
operations through post-harvest handling, packing and transport to
the market. The main implications of this damage are the reduction of
the product’s quality and economical losses related to the shelf life
diminution. For most perishable products, the shelf life is relatively
short and it is typically dictated by microbial growth related to the
application of dynamic and static loads during transportation. This
paper presents the correlation between vibration levels and
microbiological growth on strawberries and woodland strawberries
and detects the presence of volatile organic compounds (VOC) in
order to develop an intelligent logistic unit capable of monitoring
VOCs using a specific sensor system. Fresh fruits were exposed to
vibrations by means of a vibrating table in a temperature-controlled
environment. Microbiological analyses were conducted on samples,
taken at different positions along the column of the crates. The values
obtained were compared with control samples not exposed to
vibrations and the results show that different positions along the
column influence the development of bacteria, yeasts and filamentous
fungi.
Abstract: All the software engineering researches and best
industry practices aim at providing software products with high
degree of quality and functionality at low cost and less time. These
requirements are addressed by the Component Based Software
Engineering (CBSE) as well. CBSE, which deals with the software
construction by components’ assembly, is a revolutionary extension
of Software Engineering. CBSE must define and describe processes
to assure timely completion of high quality software systems that are
composed of a variety of pre built software components. Though
these features provide distinct and visible benefits in software design
and programming, they also raise some challenging problems. The
aim of this work is to summarize the pertinent issues and
considerations in CBSE to make an understanding in forms of
concepts and observations that may lead to development of newer
ways of dealing with the problems and challenges in CBSE.
Abstract: The purposes of this study are 1) to study the effects
of participatory error correction process and 2) to find out the
students’ satisfaction of such error correction process. This study is a
Quasi Experimental Research with single group, in which data is
collected 5 times preceding and following 4 experimental studies of
participatory error correction process including providing coded
indirect corrective feedback in the students’ texts with error treatment
activities. Samples include 52 2nd year English Major students,
Faculty of Humanities and Social Sciences, Suan Sunandha Rajabhat
University. Tool for experimental study includes the lesson plan of
the course; Reading and Writing English for Academic Purposes II,
and tools for data collection include 5 writing tests of short texts and
a questionnaire. Based on formative evaluation of the students’
writing ability prior to and after each of the 4 experiments, the
research findings disclose the students’ higher scores with statistical
difference at 0.00. Moreover, in terms of the effect size of such
process, it is found that for mean of the students’ scores prior to and
after the 4 experiments; d equals 0.6801, 0.5093, 0.5071, and 0.5296
respectively. It can be concluded that participatory error correction
process enables all of the students to learn equally well and there is
improvement in their ability to write short texts. Finally the students’
overall satisfaction of the participatory error correction process is in
high level (Mean = 4.39, S.D. = 0.76).
Abstract: Microalgae Meyerella planktonica is a potential
biofuel source because it can grow in bulk in either autotrophic or
heterotrophic condition. However, the quantitative growth of this
algal type is still low as it tends to precipitates on the bottom.
Besides, the lipid concentration is still low when grown in
autotrophic condition. In contrast, heterotrophic condition can
enhance the lipid concentration. The combination of autotrophic
condition and agitation treatment was conducted to increase the
density of the culture. On the other hand, a heterotrophic condition
was set up to raise the lipid production. A two-stage experiment
was applied to increase the density at the first step and to increase
the lipid concentration in the next step. The autotrophic condition
resulted higher density but lower lipid concentration compared to
heterotrophic one. The agitation treatment produced higher density
in both autotrophic and heterotrophic conditions. The two-stage
experiment managed to enhance the density during the autotrophic
stage and the lipid concentration during the heterotrophic stage.
The highest yield was performed by using 0.4% v/v glycerol as a
carbon source (2.9±0.016 x 10^6 cells w/w) attained 7 days after the
heterotrophic stage began. The lipid concentration was stable
starting from day 7.
Abstract: In this article, the antibiogram and heavy metal
resistance profile of the bacteria isolated from total 34 studied
animals (Pelophylax ridibundus = 12; Mauremys rivulata = 14;
Natrix natrix = 8) captured around the Biga Stream, are described.
There was no database information on antibiogram and heavy metal
resistance profile of bacteria from these area’s amphibians and
reptiles.
A total of 200 bacteria were successfully isolated from cloaca and
oral samples of the aquatic amphibians and reptiles as well as from
the water sample. According to Jaccard’s similarity index, the degree
of similarity in the bacterial flora was quite high among the
amphibian and reptile species under examination, whereas it was
different from the bacterial diversity in the water sample. The most
frequent isolates were A. hydrophila (31.5%), B. pseudomallei
(8.5%), and C. freundii (7%). The total numbers of bacteria obtained
were as follows: 45 in P. ridibundus, 45 in N. natrix 30 in M.
rivulata, and 80 in the water sample. The result showed that
cefmetazole was the most effective antibiotic to control the bacteria
isolated in this study and that approximately 93.33% of the bacterial
isolates were sensitive to this antibiotic. The multiple antibiotic
resistances (MAR) index indicated that P. ridibundus (0.95) > N.
natrix (0.89) > M. rivulata (0.39). Furthermore, all the tested heavy
metals (Pb+2, Cu+2, Cr+3, and Mn+2) inhibit the growth of the bacterial
isolates at different rates. Therefore, it indicated that the water source
of the animals was contaminated with both antibiotic residues and
heavy metals.
Abstract: In our research we aimed to test a managerial
approach for the fuzzy front end (FFE) of innovation by creating
controlled experiment/ business case in a breakthrough innovation
development. The experiment was in the sport industry and covered
all aspects of the customer discovery stage from ideation to
prototyping followed by patent application. In the paper we describe
and analyze mile stones, tasks, management challenges, decisions
made to create the break through innovation, evaluate overall
managerial efficiency that was at the considered FFE stage.
We set managerial outcome of the FFE stage as a valid product
concept in hand. In our paper we introduce hypothetical construct
“Q-factor” that helps us in the experiment to distinguish quality of
FFE outcomes.
The experiment simulated for entrepreneur the FFE of innovation
and put on his shoulders responsibility for the outcome of valid
product concept. While developing managerial approach to reach the
outcome there was a decision to look on product concept from the
cognitive psychology and cognitive science point of view. This view
helped us to develop the profile of a person whose projection (mental
representation) of a new product could optimize for a manager or
entrepreneur FFE activities. In the experiment this profile was tested
to develop breakthrough innovation for swimmers. Following the
managerial approach the product concept was created to help
swimmers to feel/sense water. The working prototype was developed
to estimate the product concept validity and value added effect for
customers.
Based on feedback from coachers and swimmers there were strong
positive effect that gave high value for customers, and for the
experiment – the valid product concept being developed by proposed
managerial approach for the FFE.
In conclusions there is a suggestion of managerial approach that
was derived from experiment.
Abstract: Typically, virtual communities exhibit the well-known
phenomenon of participation inequality, which means that only a
small percentage of users is responsible of the majority of
contributions. However, the sustainability of the community requires
that the group of active users must be continuously nurtured with new
users that gain expertise through a participation process. This paper
analyzes the time evolution of Open Source Software (OSS)
communities, considering users that join/abandon the community
over time and several topological properties of the network when
modeled as a social network. More specifically, the paper analyzes
the role of those users rejoining the community and their influence in
the global characteristics of the network.
Abstract: Subspace channel estimation methods have been
studied widely, where the subspace of the covariance matrix is
decomposed to separate the signal subspace from noise subspace. The
decomposition is normally done by using either the eigenvalue
decomposition (EVD) or the singular value decomposition (SVD) of
the auto-correlation matrix (ACM). However, the subspace
decomposition process is computationally expensive. This paper
considers the estimation of the multipath slow frequency hopping
(FH) channel using noise space based method. In particular, an
efficient method is proposed to estimate the multipath time delays by
applying multiple signal classification (MUSIC) algorithm which is
based on the null space extracted by the rank revealing LU (RRLU)
factorization. As a result, precise information is provided by the
RRLU about the numerical null space and the rank, (i.e., important
tool in linear algebra). The simulation results demonstrate the
effectiveness of the proposed novel method by approximately
decreasing the computational complexity to the half as compared
with RRQR methods keeping the same performance.
Abstract: The material selection in the design of the sandwich
structures is very crucial aspect because of the positive or negative
influences of the base materials to the mechanical properties of the
entire panel. In the literature, it was presented that the selection of the
skin and core materials plays very important role on the behavior of
the sandwich. Beside this, the use of the correct adhesive can make
the whole structure to show better mechanical results and behavior.
In the present work, the static three-point bending tests were
performed on the sandwiches having an aluminum alloy foam core,
the skins made of three different types of fabrics and two different
commercial adhesives (flexible polyurethane and toughened epoxy
based) at different values of support span distances by aiming the
analyses of their flexural performance in terms of absorbed energy,
peak force values and collapse mechanisms. The main results of the
flexural loading are: force-displacement curves obtained after the
bending tests, peak force and absorbed energy values, collapse
mechanisms and adhesion quality. The experimental results presented
that the sandwiches with epoxy based toughened adhesive and the
skins made of S-Glass Woven fabrics indicated the best adhesion
quality and mechanical properties. The sandwiches with toughened
adhesive exhibited higher peak force and energy absorption values
compared to the sandwiches with flexible adhesive. The use of these
sandwich structures can lead to a weight reduction of the transport
vehicles, providing an adequate structural strength under operating
conditions.
Abstract: This paper provides a quantitative measure of the
time-varying multiunit neuronal spiking activity using an entropy
based approach. To verify the status embedded in the neuronal activity
of a population of neurons, the discrete wavelet transform (DWT) is
used to isolate the inherent spiking activity of MUA. Due to the
de-correlating property of DWT, the spiking activity would be
preserved while reducing the non-spiking component. By evaluating
the entropy of the wavelet coefficients of the de-noised MUA, a
multiresolution Shannon entropy (MRSE) of the MUA signal is
developed. The proposed entropy was tested in the analysis of both
simulated noisy MUA and actual MUA recorded from cortex in rodent
model. Simulation and experimental results demonstrate that the
dynamics of a population can be quantified by using the proposed
entropy.
Abstract: Reliability allocation is quite important during early
design and development stages for a system to apportion its specified
reliability goal to subsystems. This paper improves the reliability
fuzzy allocation method, and gives concrete processes on determining
the factor and sub-factor sets, weight sets, judgment set, and
multi-stage fuzzy evaluation. To determine the weight of factor and
sub-factor sets, the modified trapezoidal numbers are proposed to
reduce errors caused by subjective factors. To decrease the fuzziness
in fuzzy division, an approximation method based on linear
programming is employed. To compute the explicit values of fuzzy
numbers, centroid method of defuzzification is considered. An
example is provided to illustrate the application of the proposed
reliability allocation method based on fuzzy arithmetic.
Abstract: Taiwan is a hyper endemic area for the Hepatitis B
virus (HBV). The estimated total number of HBsAg carriers in the
general population who are more than 20 years old is more than 3
million. Therefore, a case record review is conducted from January
2003 to June 2007 for all patients with a diagnosis of acute hepatitis
who were admitted to the Emergency Department (ED) of a
well-known teaching hospital. The cost for the use of medical
resources is defined as the total medical fee. In this study, principal
component analysis (PCA) is firstly employed to reduce the number of
dimensions. Support vector regression (SVR) and artificial neural
network (ANN) are then used to develop the forecasting model. A total
of 117 patients meet the inclusion criteria. 61% patients involved in
this study are hepatitis B related. The computational result shows that
the proposed PCA-SVR model has superior performance than other
compared algorithms. In conclusion, the Child-Pugh score and
echogram can both be used to predict the cost of medical resources for
patients with acute hepatitis in the ED.
Abstract: The number of persons with implanted cardiac
pacemakers (PM) has increased in Western countries. The aim of this
paper is to investigate the possible situations where persons with a
PM may be exposed to extremely low frequency (ELF) electric (EF)
and magnetic fields (MF) that may disturb their PM. Based on our
earlier studies, it is possible to find such high public exposure to EFs
only in some places near 400 kV power lines, where an EF may
disturb a PM in unipolar mode. Such EFs cannot be found near 110
kV power lines. Disturbing MFs can be found near welding
machines. However, we do not have measurement data from welding.
Based on literature and earlier studies at Tampere University of
Technology, it is difficult to find public EF or MF exposure that is
high enough to interfere with PMs.
Abstract: In 2010-2011, the research on zooplankton was
conducted in the southern part of the Baltic Sea to determine seasonal
variability in changes occurring throughout the zooplankton in 2010
and 2011, both in the region of Gdańsk Deep, and in the western part
of Gdańsk Bay. The research in the sea showed that the taxonomic
composition of holoplankton in the southern part of the Baltic Sea
was similar to that recorded in this region for many years. The
maximum values of abundance and biomass of zooplankton both in
the Deep and the Bay of Gdańsk were observed in the summer
season. Copepoda dominated in the composition of zooplankton for
almost the entire study period, while rotifers occurred in larger
numbers only in the summer 2010 in the Gdańsk Deep as well as in
May and July 2010 in the western part of Gdańsk Bay, and
meroplankton – in April 2011.
Abstract: The aim of this paper is to investigate accidents and
close call situations connected to the use of mobile phones in
working-age people ≥ 50 years old. The paper is part of a crosssectional
study that was carried out in 2002 in 15,000 working-age
Finns. The study showed that mobile-phone-related accidents and
close call situations, both at work and at leisure, are more common in
people under 50 years that in people ≥ 50 years old. However, people
under 50 use mobile phones more than those aged ≥ 50.
Abstract: The performance of box-type solar cookers has been
reported by several researchers but little attention was paid to the
effect of the type of insulation material on the energy and exergy
efficiency of these cookers. This research aimed at evaluating the
energy and exergy efficiencies of the box-type cookers containing
different insulation materials. Energy and exergy efficiencies of five
box-type solar cookers insulated with maize cob, air (control), maize
husk, coconut coir and polyurethane foam respectively were obtained
over a period of three years. The cookers were evaluated using water
heating test procedures in determining the energy and exergy
analysis. The results were subjected to statistical analysis using
ANOVA. The result shows that the average energy input for the five
solar cookers were: 245.5, 252.2, 248.7, 241.5 and 245.5J
respectively while their respective average energy losses were: 201.2,
212.7, 208.4, 189.1 and 199.8J. The average exergy input for five
cookers were: 228.2, 234.4, 231.1, 224.4 and 228.2J respectively
while their respective average exergy losses were: 223.4, 230.6,
226.9, 218.9 and 223.0J. The energy and exergy efficiency was
highest in the cooker with coconut coir (37.35 and 3.90%
respectively) in the first year but was lowest for air (11 and 1.07%
respectively) in the third year. Statistical analysis showed significant
difference between the energy and exergy efficiencies over the years.
These results reiterate the importance of a good insulating material
for a box-type solar cooker.
Abstract: We present a framework of researcher knowledge
development in conducting a study in mathematics education. The
key components of the framework are: knowledge germane to
conducting a particular study, processes of knowledge accumulation,
and catalyzing filters that influence a researcher decision making.
The components of the framework originated from a confluence
between constructs and theories in Mathematics Education, Higher
Education and Sociology. Drawing on a self-reflective interview with
a leading researcher in mathematics education, Professor Michèle
Artigue, we illustrate how the framework can be utilized in data
analysis. Criteria for framework evaluation are discussed.