Abstract: This qualitative, quantitative mixed-method study explores how students- motivation and interest in creative hands-on activities affected their conceptual understanding of science. The objectives of this research include developing a greater understanding about how creative activities, incorporated into the classroom as instructional strategies, increase student motivation and their learning or mastery of science concepts. The creative activities are viewed as a motivational tool, a specific type of task, which have an impact on student goals. Pre-and-post tests, pre-and-post interviews, and student responses measure motivational-goal theory variables, interest in the activity, and conceptual change. Implications for education and future research will be discussed.
Abstract: In this work, new experimental data for slugging
frequency in inclined gas-liquid flow are reported, and a new
correlation is proposed. Scale experiments were carried out using a
mixture of air and water in a 6 m long pipe. Two different pipe
diameters were used, namely, 38 and 67 mm. The data were taken
with capacitance type sensors at a data acquisition frequency of 200
Hz over an interval of 60 seconds. For the range of flow conditions
studied, the liquid superficial velocity is observed to influence the
frequency strongly. A comparison of the present data with
correlations available in the literature reveals a lack of agreement. A
new correlation for slug frequency has been proposed for the inclined
flow, which represents the main contribution of this work.
Abstract: HIV-1 genome is highly heterogeneous. Due to this
variation, features of HIV-I genome is in a wide range. For this
reason, the ability to infection of the virus changes depending on
different chemokine receptors. From this point of view, R5 HIV
viruses use CCR5 coreceptor while X4 viruses use CXCR5 and
R5X4 viruses can utilize both coreceptors. Recently, in
Bioinformatics, R5X4 viruses have been studied to classify by using
the experiments on HIV-1 genome.
In this study, R5X4 type of HIV viruses were classified using
Auto Regressive (AR) model through Artificial Neural Networks
(ANNs). The statistical data of R5X4, R5 and X4 viruses was
analyzed by using signal processing methods and ANNs. Accessible
residues of these virus sequences were obtained and modeled by AR
model since the dimension of residues is large and different from
each other. Finally the pre-processed data was used to evolve various
ANN structures for determining R5X4 viruses. Furthermore ROC
analysis was applied to ANNs to show their real performances. The
results indicate that R5X4 viruses successfully classified with high
sensitivity and specificity values training and testing ROC analysis
for RBF, which gives the best performance among ANN structures.
Abstract: Midpoint filter is quite effective in recovering the
images confounded by the short-tailed (uniform) noise. It, however,
performs poorly in the presence of additive long-tailed (impulse)
noise and it does not preserve the edge structures of the image
signals. Median smoother discards outliers (impulses) effectively, but
it fails to provide adequate smoothing for images corrupted with nonimpulse
noise. In this paper, two nonlinear techniques for image
filtering, namely, New Filter I and New Filter II are proposed based
on a nonlinear high-pass filter algorithm. New Filter I is constructed
using a midpoint filter, a highpass filter and a combiner. It suppresses
uniform noise quite well. New Filter II is configured using an alpha
trimmed midpoint filter, a median smoother of window size 3x3, the
high pass filter and the combiner. It is robust against impulse noise
and attenuates uniform noise satisfactorily. Both the filters are shown
to exhibit good response at the image boundaries (edges). The
proposed filters are evaluated for their performance on a test image
and the results obtained are included.
Abstract: The prediction of meteorological parameters at a
meteorological station is an interesting and open problem. A firstorder
linear dynamic model GM(1,1) is the main component of the
grey system theory. The grey model requires only a few previous data
points in order to make a real-time forecast. In this paper, we
consider the daily average ambient temperature as a time series and
the grey model GM(1,1) applied to local prediction (short-term
prediction) of the temperature. In the same case study we use a fuzzy
predictive model for global prediction. We conclude the paper with a
comparison between local and global prediction schemes.
Abstract: Most of researches for conventional simulations were
studied focusing on flocks with a single species. While there exist the
flocking behaviors with a single species in nature, the flocking
behaviors are frequently observed with multi-species. This paper
studies on the flocking simulation for heterogeneous agents. In order
to simulate the flocks for heterogeneous agents, the conventional
method uses the identifier of flock, while the proposed method defines
the feature vector of agent and uses the similarity between agents by
comparing with those feature vectors. Based on the similarity, the
paper proposed the attractive force and repulsive force and then
executed the simulation by applying two forces. The results of
simulation showed that flock formation with heterogeneous agents is
very natural in both cases. In addition, it showed that unlike the
existing method, the proposed method can not only control the density
of the flocks, but also be possible for two different groups of agents to
flock close to each other if they have a high similarity.
Abstract: The persistent nature of perfluorochemicals (PFCs) has attracted global concern in recent years. Perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) are the most commonly found PFC compounds, and thus their fate and transport play key roles in PFC distribution in the natural environment. The kinetic behavior of PFOS or PFOA on boehmite consists of a fast adsorption process followed by a slow adsorption process which may be attributed to the slow transport of PFOS or PFOA into the boehmite pore surface. The adsorption isotherms estimated the maximum adsorption capacities of PFOS and PFOA on boehmite as 0.877 μg/m2 and 0.633 μg/m2, with the difference primarily due to their different functional groups. The increase of solution pH led to a moderate decrease of PFOS and PFOA adsorption, owing to the increase of ligand exchange reactions and the decrease of electrostatic interactions. The presence of NaCl in solution demonstrated negative effects for PFOS and PFOA adsorption on boehmite surfaces, with potential mechanisms being electrical double layer compression, competitive adsorption of chloride.
Abstract: The purpose of this work was to inspect the potential
of vincristine-dextran complex loaded solid lipid nanoparticles for
drug delivery to the brain.
The nanoparticles were stained with a fluorescence dye and their
plasma pharmacokinetic and brain concentrations were investigated
following injection to rats.
The result revealed a significant improvement in the plasma
concentration profile of the SLN injected animals as well as a sharp
increased concentration in the brains.
Abstract: In this paper we present a substantiation of a new
Laguerre-s type iterative method for solving of a nonlinear
polynomial equations systems with real coefficients. The problems of
its implementation, including relating to the structural choice of
initial approximations, were considered. Test examples demonstrate
the effectiveness of the method at the solving of many practical
problems solving.
Abstract: Liners are made to protect the groundwater table from
the infiltration of leachate which normally carries different kinds of
toxic materials from landfills. Although these liners are engineered to
last for long period of time; unfortunately these liners fail; therefore,
toxic materials pass to groundwater. This paper focuses on the
changes of the hydraulic conductivity of a sand-bentonite liner due to
the infiltration of biofuel and ethanol fuel. Series of laboratory tests
were conducted in 20-cm-high PVC columns. Several compositions
of sand-bentonite liners were tested: 95% sand: 5% bentonite; 90%
sand: 10% bentonite; and 100% sand (passed mesh #40). The
columns were subjected to extreme pressures of 40 kPa, and 100 kPa
to evaluate the transport of alternative fuels (biofuel and ethanol
fuel). For comparative studies, similar tests were carried out using
water. Results showed that hydraulic conductivity increased due to
the infiltration of alternative fuels through the liners. Accordingly,
the increase in the hydraulic conductivity showed significant
dependency on the type of liner mixture and the characteristics of the
liquid. The hydraulic conductivity of a liner (subjected to biofuel
infiltration) consisting of 5% bentonite: 95% sand under pressure of
40 kPa and 100 kPa had increased by one fold. In addition, the
hydraulic conductivity of a liner consisting of 10% bentonite: 90%
sand under pressure of 40 kPa and 100 kPa and infiltrated by biofuel
had increased by three folds. On the other hand, the results obtained
by water infiltration under 40 kPa showed lower hydraulic
conductivities of 1.50×10-5 and 1.37×10-9 cm/s for 5% bentonite:
95% sand, and 10% bentonite: 90% sand, respectively. Similarly,
under 100 kPa, the hydraulic conductivities were 2.30×10-5 and
1.90×10-9 cm/s for 5% bentonite: 95% sand, and 10% bentonite: 90%
sand, respectively.
Abstract: In the present work the internal sulfate attack on
pastes made from pure clinker phases was studied. Two binders were
produced: (a) a binder with 2% C3A and 18% C4AF content; (b) a
binder with 10% C3A and C4AF content each. Gypsum was used as
the sulfate bearing compound, while calcium carbonate added to
differentiate the binders produced. The phases formed were identified
by XRD analysis. The results showed that ettringite was the
deterioration phase detected in the case of the low C3A content
binder. Carbonation occurred in the specimen without calcium
carbonate addition, while portlandite was observed in the one
containing calcium carbonate. In the case of the high C3A content
binder, traces of thaumasite were detected when calcium carbonate
was not incorporated in the binder. A solid solution of thaumasite and
ettringite was found when calcium carbonate was added. The amount
of C3A had not fully reacted with sulfates, since its corresponding
peaks were detected.
Abstract: German electricity European options on futures using
Lévy processes for the underlying asset are examined. Implied
volatility evolution, under each of the considered models, is
discussed after calibrating for the Merton jump diffusion (MJD),
variance gamma (VG), normal inverse Gaussian (NIG), Carr, Geman,
Madan and Yor (CGMY) and the Black and Scholes (B&S) model.
Implied volatility is examined for the entire sample period, revealing
some curious features about market evolution, where data fitting
performances of the five models are compared. It is shown that
variance gamma processes provide relatively better results and that
implied volatility shows significant differences through time, having
increasingly evolved. Volatility changes for changed uncertainty, or
else, increasing futures prices and there is evidence for the need to
account for seasonality when modelling both electricity spot/futures
prices and volatility.
Abstract: The pseudorandom number generators based on linear
feedback shift registers (LFSRs), are very quick, easy and secure in
the implementation of hardware and software. Thus they are very
popular and widely used. But LFSRs lead to fairly easy
cryptanalysis due to their completely linearity properties. In this
paper, we propose a stochastic generator, which is called Random
Feedback Shift Register (RFSR), using stochastic transformation
(Random block) with one-way and non-linearity properties.
Abstract: The fluid flow and the properties of the hydraulic
fluid inside a torque converter are the main topics of interest in this
research. The primary goal is to investigate the applicability of
various viscous fluids inside the torque converter. The Taguchi
optimization method is adopted to analyse the fluid flow in a torque
converter from a design perspective. Calculations are conducted in
maximizing the pressure since greater the pressure, greater the torque
developed. Using the values of the S/N ratios obtained, graphs are
plotted. Computational Fluid Dynamics (CFD) analysis is also
conducted.
Abstract: The fast growth in complexity coupled with requests for shorter development periods for embedded systems are bringing demands towards a more effective, i.e. higher-abstract, design process for hardaware/software integrated design. In Software Engineering area, Model Driven Architecture (MDA) and Executable UML (xUML) has been accepted to bring further improvement in software design. This paper constructs MDA and xUML stepwise transformations from an abstract specification model to a more concrete implementation model using the refactoring technique for hardaware/software integrated design. This approach provides clear and structured models which enables quick exploration and synthesis, and early stage verification.
Abstract: This paper presents the design and layout of a two stage, high speed operational amplifiers using standard 0.35um CMOS technology. The design procedure involves designing the bias circuit, the differential input pair, and the gain stage using CAD tools. Both schematic and layout of the operational amplifier along with the comparison in the results of the two has been presented. The operational amplifier designed, has a gain of 93.51db at low frequencies. It has a gain bandwidth product of 55.07MHz, phase margin of 51.9º and a slew rate of 22v/us for a load of capacitor of 10pF.
Abstract: Severe heart failure is a common problem that has a significant effect on health expenditures in industrialized countries; moreover it reduces patient-s quality of life. However, current research usually focuses either on detailed modeling of the heart or on detailed modeling of the cardiovascular system. Thus, this paper aims to present a sophisticated model of the heart enhanced with an extensive model of the cardiovascular system. Special interest is on the pressure and flow values close to the heart since these values are critical to accurately diagnose causes of heart failure. The model is implemented in Dymola an object-oriented, physical modeling language. Results achieved with the novel model show overall feasibility of the approach. Moreover, results are illustrated and compared to other models. The novel model shows significant improvements.
Abstract: This study presents energy saving in general-purpose
pumps widely used in industrial applications. Such pumps are
normally driven by a constant-speed electrical motor which in most
applications must support varying load conditions. This is equivalent
to saying the loading conditions mismatch the designed optimal
energy consumption requirements of the intended application thus
resulting in substantial energy losses. In the held experiments it was
indicated that combination of mechanical and electrical speed drives
can contribute to lower energy consumption in the pump without
negatively distorting the required performance indices of a typical
centrifugal pump at substantially lower energy consumption. The
registered energy savings were recorded to be within the 15-40%
margin. It was also indicated that although VSDs are installed at a
cost, the financial burden is balanced against the earnings resulting
from the associated energy savings.
Abstract: Chinese Idioms are a type of traditional Chinese idiomatic
expressions with specific meanings and stereotypes structure
which are widely used in classical Chinese and are still common in
vernacular written and spoken Chinese today. Currently, Chinese
Idioms are retrieved in glossary with key character or key word in
morphology or pronunciation index that can not meet the need of
searching semantically. OCIRS is proposed to search the desired
idiom in the case of users only knowing its meaning without any key
character or key word. The user-s request in a sentence or phrase will
be grammatically analyzed in advance by word segmentation, key
word extraction and semantic similarity computation, thus can be
mapped to the idiom domain ontology which is constructed to provide
ample semantic relations and to facilitate description logics-based
reasoning for idiom retrieval. The experimental evaluation shows that
OCIRS realizes the function of searching idioms via semantics, obtaining
preliminary achievement as requested by the users.
Abstract: Based on the sources- smoothed rank profile (SRP) and modified minimum description length (MMDL) principle, a method for estimation of the source coherency structure (SCS) and the number of wideband sources is proposed in this paper. Instead of focusing, we first use a spatial smoothing technique to pre-process the array covariance matrix of each frequency for de-correlating the sources and then use smoothed rank profile to determine the SCS and the number of wideband sources. We demonstrate the availability of the method by numerical simulations.