Abstract: The term hybrid composite refers to the composite
containing more than one type of fiber material as reinforcing fillers.
It has become attractive structural material due to the ability of
providing better combination of properties with respect to single fiber
containing composite. The eco-friendly nature as well as processing
advantage, light weight and low cost have enhanced the attraction
and interest of natural fiber reinforced composite. The objective of
present research is to study the mechanical properties of jute-coir
fiber reinforced hybrid polypropylene (PP) composite according to
filler loading variation. In the present work composites were
manufactured by using hot press machine at four levels of fiber
loading (5, 10, 15 and 20 wt %). Jute and coir fibers were utilized at a
ratio of (1:1) during composite manufacturing. Tensile, flexural,
impact and hardness tests were conducted for mechanical
characterization. Tensile test of composite showed a decreasing trend
of tensile strength and increasing trend of the Young-s modulus with
increasing fiber content. During flexural, impact and hardness tests,
the flexural strength, flexural modulus, impact strength and hardness
were found to be increased with increasing fiber loading. Based on
the fiber loading used in this study, 20% fiber reinforced composite
resulted the best set of mechanical properties.
Abstract: The spiral angle of the elementary cellulose fibril in
the wood cell wall, often called microfibril angle, (MFA). Microfibril
angle in hardwood is one of the key determinants of solid timber
performance due to its strong influence on the stiffness, strength,
shrinkage, swelling, thermal-dynamics mechanical properties and
dimensional stability of wood. Variation of MFA (degree) in the S2
layer of the cell walls among Acacia mangium trees was determined
using small-angle X-ray scattering (SAXS). The length and
orientation of the microfibrils of the cell walls in the irradiated
volume of the thin samples are measured using SAXS and optical
microscope for 3D surface measurement. The undetermined
parameters in the analysis are the MFA, (M) and the standard
deviation (σФ) of the intensity distribution arising from the wandering
of the fibril orientation about the mean value. Nine separate pairs of
values are determined for nine different values of the angle of the
incidence of the X-ray beam relative to the normal to the radial
direction in the sample. The results show good agreement. The
curve distribution of scattered intensity for the real cell wall structure
is compared with that calculated with that assembly of rectangular
cells with the same ratio of transverse to radial cell wall length. It is
demonstrated that for β = 45°, the peaks in the curve intensity
distribution for the real and the rectangular cells coincide. If this
peak position is Ф45, then the MFA can be determined from the
relation M = tan-1 (tan Ф45 / cos 45°), which is precise for rectangular
cells. It was found that 92.93% of the variation of MFA can be
attributed to the distance from pith to bark. Here we shall present our
results of the MFA in the cell wall with respect to its shape, structure
and the distance from pith to park as an important fast check and yet
accurate towards the quality of wood, its uses and application.
Abstract: e-Government structures permits the government to operate in a more transparent and accountable manner of which it increases the power of the individual in relation to that of the government. This paper identifies the factors that determine customer-s attitude towards e-Government services using a theoretical model based on the Technology Acceptance Model. Data relating to the constructs were collected from 200 respondents. The research model was tested using Structural Equation Modeling (SEM) techniques via the Analysis of Moment Structure (AMOS 16) computer software. SEM is a comprehensive approach to testing hypotheses about relations among observed and latent variables. The proposed model fits the data well. The results demonstrated that e- Government services acceptance can be explained in terms of compatibility and attitude towards e-Government services. The setup of the e-Government services will be compatible with the way users work and are more likely to adopt e-Government services owing to their familiarity with the Internet for various official, personal, and recreational uses. In addition, managerial implications for government policy makers, government agencies, and system developers are also discussed.
Abstract: This paper presents a means for reducing the torque
variation during the revolution of a vertical-axis water turbine
(VAWaterT) by increasing the blade number. For this purpose, twodimensional
CFD analyses have been performed on a straight-bladed
Darrieus-type rotor. After describing the computational model and
the relative validation procedure, a complete campaign of
simulations, based on full RANS unsteady calculations, is proposed
for a three, four and five-bladed rotor architectures, characterized by
a NACA 0025 airfoil. For each proposed rotor configuration, flow
field characteristics are investigated at several values of tip speed
ratio, allowing a quantification of the influence of blade number on
flow geometric features and dynamic quantities, such as rotor torque
and power. Finally, torque and power curves are compared for the
three analyzed architectures, achieving a quantification of the effect
of blade number on overall rotor performance.
Abstract: The POD-assisted projective integration method based on the equation-free framework is presented in this paper. The method is essentially based on the slow manifold governing of given system. We have applied two variants which are the “on-line" and “off-line" methods for solving the one-dimensional viscous Bergers- equation. For the on-line method, we have computed the slow manifold by extracting the POD modes and used them on-the-fly along the projective integration process without assuming knowledge of the underlying slow manifold. In contrast, the underlying slow manifold must be computed prior to the projective integration process for the off-line method. The projective step is performed by the forward Euler method. Numerical experiments show that for the case of nonperiodic system, the on-line method is more efficient than the off-line method. Besides, the online approach is more realistic when apply the POD-assisted projective integration method to solve any systems. The critical value of the projective time step which directly limits the efficiency of both methods is also shown.
Abstract: Following the loss of NASA's Space Shuttle
Columbia in 2003, it was determined that problems in the agency's
organization created an environment that led to the accident. One
component of the proposed solution resulted in the formation of the
NASA Engineering Network (NEN), a suite of information retrieval
and knowledge-sharing tools. This paper describes the
implementation of communities of practice, which are formed along
engineering disciplines. Communities of practice enable engineers to
leverage their knowledge and best practices to collaborate and take
information learning back to their jobs and embed it into the
procedures of the agency. This case study offers insight into using
traditional engineering disciplines for virtual collaboration, including
lessons learned during the creation and establishment of NASA-s
communities.
Abstract: Current image-based individual human recognition
methods, such as fingerprints, face, or iris biometric modalities
generally require a cooperative subject, views from certain aspects,
and physical contact or close proximity. These methods cannot
reliably recognize non-cooperating individuals at a distance in the
real world under changing environmental conditions. Gait, which
concerns recognizing individuals by the way they walk, is a relatively
new biometric without these disadvantages. The inherent gait
characteristic of an individual makes it irreplaceable and useful in
visual surveillance.
In this paper, an efficient gait recognition system for human
identification by extracting two features namely width vector of
the binary silhouette and the MPEG-7-based region-based shape
descriptors is proposed. In the proposed method, foreground objects
i.e., human and other moving objects are extracted by estimating
background information by a Gaussian Mixture Model (GMM) and
subsequently, median filtering operation is performed for removing
noises in the background subtracted image. A moving target classification
algorithm is used to separate human being (i.e., pedestrian)
from other foreground objects (viz., vehicles). Shape and boundary
information is used in the moving target classification algorithm.
Subsequently, width vector of the outer contour of binary silhouette
and the MPEG-7 Angular Radial Transform coefficients are taken as
the feature vector. Next, the Principal Component Analysis (PCA)
is applied to the selected feature vector to reduce its dimensionality.
These extracted feature vectors are used to train an Hidden Markov
Model (HMM) for identification of some individuals. The proposed
system is evaluated using some gait sequences and the experimental
results show the efficacy of the proposed algorithm.
Abstract: To evaluate the ability to predict xerostomia after
radiotherapy, we constructed and compared neural network and
logistic regression models. In this study, 61 patients who completed a
questionnaire about their quality of life (QoL) before and after a full
course of radiation therapy were included. Based on this questionnaire,
some statistical data about the condition of the patients’ salivary
glands were obtained, and these subjects were included as the inputs of
the neural network and logistic regression models in order to predict
the probability of xerostomia. Seven variables were then selected from
the statistical data according to Cramer’s V and point-biserial
correlation values and were trained by each model to obtain the
respective outputs which were 0.88 and 0.89 for AUC, 9.20 and 7.65
for SSE, and 13.7% and 19.0% for MAPE, respectively. These
parameters demonstrate that both neural network and logistic
regression methods are effective for predicting conditions of parotid
glands.
Abstract: Rice, which is the staple food in Sierra Leone, is
consumed on a daily basis. It is the most imperative food crop
extensively grown by farmers across all ecologies in the country.
Though much attention is now given to rice grain production through
the small holder commercialization programme (SHCP), however, no
attention has been given in investigating the limitations faced by rice
producers. This paper will contribute to attempts to overcome the
development challenges caused by food insecurity. The objective of
this paper is thus, to analysis the relationship between rice production
and the domestic retail price of rice. The study employed a log linear
model in which, the quantity of rice produced is the dependent
variable, quantity of rice imported, price of imported rice and price of
domestic rice as explanatory variables. Findings showed that, locally
produced rice is even more expensive than the imported rice per ton,
and almost all the inhabitants in the capital city which hosts about
65% of the entire population of the country favor imported rice, as it
is free from stones with other impurities. On the other hand, to
control price and simultaneously increase rice production, the
government should purchase the rice from the farmers and then sell to private retailers.
Abstract: Cancers could normally be marked by a number of
differentially expressed genes which show enormous potential as
biomarkers for a certain disease. Recent years, cancer classification
based on the investigation of gene expression profiles derived by
high-throughput microarrays has widely been used. The selection of
discriminative genes is, therefore, an essential preprocess step in
carcinogenesis studies. In this paper, we have proposed a novel gene
selector using information-theoretic measures for biological
discovery. This multivariate filter is a four-stage framework through
the analyses of feature relevance, feature interdependence, feature
redundancy-dependence and subset rankings, and having been
examined on the colon cancer data set. Our experimental result show
that the proposed method outperformed other information theorem
based filters in all aspect of classification errors and classification
performance.
Abstract: In this study, active tendons with Proportional Integral
Derivation type controllers were applied to a SDOF and a MDOF
building model. Physical models of buildings were constituted with
virtual springs, dampers and rigid masses. After that, equations of
motion of all degrees of freedoms were obtained. Matlab Simulink
was utilized to obtain the block diagrams for these equations of
motion. Parameters for controller actions were found by using a trial
method. After earthquake acceleration data were applied to the
systems, building characteristics such as displacements, velocities,
accelerations and transfer functions were analyzed for all degrees of
freedoms. Comparisons on displacement vs. time, velocity vs. time,
acceleration vs. time and transfer function (Db) vs. frequency (Hz)
were made for uncontrolled and controlled buildings. The results
show that the method seems feasible.
Abstract: The common bean is the most important grain legume for direct human consumption in the world and BCMV is one of the world's most serious bean diseases that can reduce yield and quality of harvested product. To determine the best tolerance index to BCMV and recognize tolerant genotypes, 2 experiments were conducted in field conditions. Twenty five common bean genotypes were sown in 2 separate RCB design with 3 replications under contamination and non-contamination conditions. On the basis of the results of indices correlations GMP, MP and HARM were determined as the most suitable tolerance indices. The results of principle components analysis indicated 2 first components totally explained 98.52% of variations among data. The first and second components were named potential yield and stress susceptible respectively. Based on the results of BCMV tolerance indices assessment and biplot analysis WA8563-4, WA8563-2 and Cardinal were the genotypes that exhibited potential seed yield under contamination and noncontamination conditions.
Abstract: The paper presents the optimization problem for the
multi-element synthetic transmit aperture method (MSTA) in
ultrasound imaging applications. The optimal choice of the transmit
aperture size is performed as a trade-off between the lateral
resolution, penetration depth and the frame rate. Results of the
analysis obtained by a developed optimization algorithm are
presented. Maximum penetration depth and the best lateral resolution
at given depths are chosen as the optimization criteria. The
optimization algorithm was tested using synthetic aperture data of
point reflectors simulated by Filed II program for Matlab® for the
case of 5MHz 128-element linear transducer array with 0.48 mm
pitch are presented. The visualization of experimentally obtained
synthetic aperture data of a tissue mimicking phantom and in vitro
measurements of the beef liver are also shown. The data were
obtained using the SonixTOUCH Research systemequipped with a
linear 4MHz 128 element transducerwith 0.3 mm element pitch, 0.28
mm element width and 70% fractional bandwidth was excited by one
sine cycle pulse burst of transducer's center frequency.
Abstract: The number of framework conceived for e-learning
constantly increase, unfortunately the creators of learning materials
and educational institutions engaged in e-formation adopt a
“proprietor" approach, where the developed products (courses,
activities, exercises, etc.) can be exploited only in the framework
where they were conceived, their uses in the other learning
environments requires a greedy adaptation in terms of time and
effort. Each one proposes courses whose organization, contents,
modes of interaction and presentations are unique for all learners,
unfortunately the latter are heterogeneous and are not interested by
the same information, but only by services or documents adapted to
their needs. Currently the new tendency for the framework
conceived for e-learning, is the interoperability of learning materials,
several standards exist (DCMI (Dublin Core Metadata Initiative)[2],
LOM (Learning Objects Meta data)[1], SCORM (Shareable Content
Object Reference Model)[6][7][8], ARIADNE (Alliance of Remote
Instructional Authoring and Distribution Networks for Europe)[9],
CANCORE (Canadian Core Learning Resource Metadata
Application Profiles)[3]), they converge all to the idea of learning
objects. They are also interested in the adaptation of the learning
materials according to the learners- profile. This article proposes an
approach for the composition of courses adapted to the various
profiles (knowledge, preferences, objectives) of learners, based on
two ontologies (domain to teach and educational) and the learning
objects.
Abstract: It-s known that incorporating prior knowledge into support
vector regression (SVR) can help to improve the approximation
performance. Most of researches are concerned with the incorporation
of knowledge in the form of numerical relationships. Little work,
however, has been done to incorporate the prior knowledge on the
structural relationships among the variables (referred as to Structural
Prior Knowledge, SPK). This paper explores the incorporation of SPK
in SVR by constructing appropriate admissible support vector kernel
(SV kernel) based on the properties of reproducing kernel (R.K).
Three-levels specifications of SPK are studied with the corresponding
sub-levels of prior knowledge that can be considered for the method.
These include Hierarchical SPK (HSPK), Interactional SPK (ISPK)
consisting of independence, global and local interaction, Functional
SPK (FSPK) composed of exterior-FSPK and interior-FSPK. A
convenient tool for describing the SPK, namely Description Matrix
of SPK is introduced. Subsequently, a new SVR, namely Motivated
Support Vector Regression (MSVR) whose structure is motivated
in part by SPK, is proposed. Synthetic examples show that it is
possible to incorporate a wide variety of SPK and helpful to improve
the approximation performance in complex cases. The benefits of
MSVR are finally shown on a real-life military application, Air-toground
battle simulation, which shows great potential for MSVR to
the complex military applications.
Abstract: A new chelating resin is prepared by coupling Amberlite XAD-4 with 1-amino-2-naphthole through an azo spacer. The resulting sorbent has been characterized by FT-IR, elemental analysis and thermogravimetric analysis (TGA) and studied for preconcentrating of Fe (II) using flame atomic absorption spectrometry (FAAS) for metal monitoring. The optimum pH value for sorption of the iron ions was 6.5. The resin was subjected to evaluation through batch binding of mentioned metal ion. Quantitative desorption occurs instantaneously with 0.5 M HNO3. The sorption capacity was found 4.1 mmol.g-1 of resin for Fe (II) in the aqueous solution. The chelating resin can be reused for 10 cycles of sorption-desorption without any significant change in sorption capacity. A recovery of 97% was obtained the metal ions with 0.5 M HNO3 as eluting agent. The method was applied for metal ions determination from industrial waste water sample.
Abstract: Nanostructured Iron Oxide with different
morphologies of rod-like and granular have been suc-cessfully
prepared via a solid-state reaction in the presence of NaCl, NaBr, NaI
and NaN3, respectively. The added salts not only prevent a drastic
increase in the size of the products but also provide suitable
conditions for the oriented growth of primary nanoparticles. The
formation mechanisms of these materials by solid-state reaction at
ambient temperature are proposed. The photocatalytic experiments
for congo red (CR) have demonstrated that the mixture of α-Fe2O3
and Fe3O4 nanostructures were more efficient than α-Fe2O3
nanostructures.
Abstract: Gold passbook is an investing tool that is especially
suitable for investors to do small investment in the solid gold. The gold
passbook has the lower risk than other ways investing in gold, but its
price is still affected by gold price. However, there are many factors
can cause influences on gold price. Therefore, building a model to
predict the price of gold passbook can both reduce the risk of
investment and increase the benefits. This study investigates the
important factors that influence the gold passbook price, and utilize
the Group Method of Data Handling (GMDH) to build the predictive
model. This method can not only obtain the significant variables but
also perform well in prediction. Finally, the significant variables of
gold passbook price, which can be predicted by GMDH, are US dollar
exchange rate, international petroleum price, unemployment rate,
whole sale price index, rediscount rate, foreign exchange reserves,
misery index, prosperity coincident index and industrial index.
Abstract: This paper suggests an improved integer frequency
offset (IFO) estimation scheme using P1 symbol for orthogonal
frequency division multiplexing (OFDM) based the second generation
terrestrial digital video broadcasting (DVB-T2) system. Proposed
IFO estimator is designed by a low-complexity blind IFO estimation
scheme, which is implemented with complex additions. Also, we
propose active carriers (ACs) selection scheme in order to prevent
performance degradation in blind IFO estimation. The simulation
results show that under the AWGN and TU6 channels, the proposed
method has low complexity than conventional method and almost
similar performance in comparison with the conventional method.
Abstract: A complete spectral representation for the
electromagnetic field of planar multilayered waveguides
inhomogeneously filled with omega media is presented. The problem
of guided electromagnetic propagation is reduced to an eigenvalue
equation related to a 2 ´ 2 matrix differential operator. Using the
concept of adjoint waveguide, general bi-orthogonality relations for
the hybrid modes (either from the discrete or from the continuous
spectrum) are derived. For the special case of homogeneous layers
the linear operator formalism is reduced to a simple 2 ´ 2 coupling
matrix eigenvalue problem. Finally, as an example of application, the
surface and the radiation modes of a grounded omega slab waveguide
are analyzed.