Abstract: Computer education is referred to as the knowledge
and ability to use computers and related technology efficiently, with a
range of skills covering levels from basic use to advance. Computer
continues to make an ever-increasing impact on all aspect of human
endeavours such as education. With numerous benefits of computer
education, what are the insights of students on computer education?
This study investigated the perception of senior secondary school
students on computer education in Federal Capital Territory (FCT),
Abuja, Nigeria. A sample of 7500 senior secondary schools students
was involved in the study, one hundred (100) private and fifty (50)
public schools within FCT. They were selected by using simple
random sampling technique. A questionnaire [PSSSCEQ] was
developed and validated through expert judgement and reliability coefficient
of 0.84 was obtained. It was used to gather relevant data on
computer education. Findings confirmed that the students in the FCT
had positive perception on computer education. Some factors were
identified that affect students’ perception on computer education. The
null hypotheses were tested using t-test and ANOVA statistical
analyses at 0.05 level of significance. Based on these findings, some
recommendations were made which include competent teachers
should be employed into all secondary schools. This will help
students to acquire relevant knowledge in computer education,
technological supports should be provided to all secondary schools;
this will help the users (students) to solve specific problems in
computer education and financial supports should be provided to
procure computer facilities that will enhance the teaching and the
learning of computer education.
Abstract: In this paper, a linear mixed model which has two
random effects is broken up into two models. This thesis gets
the parameter estimation of the original model and an estimation’s
statistical qualities based on these two models. Then many important
properties are given by comparing this estimation with other general
estimations. At the same time, this paper proves the analysis of
variance estimate (ANOVAE) about σ2 of the original model is equal
to the least-squares estimation (LSE) about σ2 of these two models.
Finally, it also proves that this estimation is better than ANOVAE
under Stein function and special condition in some degree.
Abstract: Lightweight and efficient structures have the aim to
enhance the efficiency of the components in various industries.
Toward this end, composites are one of the most widely used
materials because of durability, high strength and modulus, and low
weight. One type of the advanced composites is grid-stiffened
composite (GSC) structures, which have been extensively considered
in aerospace, automotive, and aircraft industries. They are one of the
top candidates for replacing some of the traditional components,
which are used here. Although there are a good number of published
surveys on the design aspects and fabrication of GSC structures, little
systematic work has been reported on their material modification to
improve their properties, to our knowledge. Matrix modification
using nanoparticles is an effective method to enhance the flexural
properties of the fibrous composites. In the present study, a silanecoupling
agent (3-glycidoxypropyltrimethoxysilane/3-GPTS) was
introduced onto the silica (SiO2) nanoparticle surface and its effects
on the three-point flexural response of isogrid E-glass/epoxy
composites were assessed. Based on the Fourier Transform Infrared
Spectrometer (FTIR) spectra, it was inferred that the 3-GPTS
coupling agent was successfully grafted onto the surface of SiO2
nanoparticles after modification. Flexural test revealed an
improvement of 16%, 14%, and 36% in stiffness, maximum load and
energy absorption of the isogrid specimen filled with 3 wt.% 3-
GPTS/SiO2 compared to the neat one. It would be worth mentioning
that in these structures, considerable energy absorption was observed
after the primary failure related to the load peak. In addition, 3-
GPTMS functionalization had a positive effect on the flexural
behavior of the multiscale isogrid composites. In conclusion, this
study suggests that the addition of modified silica nanoparticles is a
promising method to improve the flexural properties of the gridstiffened
fibrous composite structures.
Abstract: Mineral product, waste concrete (fine aggregates),
waste in the optical field, industry, and construction employ separators
to separate solids and classify them according to their size. Various
sorting machines are used in the industrial field such as those operating
under electrical properties, centrifugal force, wind power, vibration,
and magnetic force. Study on separators has been carried out to
contribute to the environmental industry. In this study, we perform
CFD analysis for understanding the basic mechanism of the separation
of waste concrete (fine aggregate) particles from air with a machine
built with a rotor with blades. In CFD, we first performed
two-dimensional particle tracking for various particle sizes for the
model with 1 degree, 1.5 degree, and 2 degree angle between each
blade to verify the boundary conditions and the method of rotating
domain method to be used in 3D. Then we developed 3D numerical
model with ANSYS CFX to calculate the air flow and track the
particles. We judged the capability of particle separation for given size
by counting the number of particles escaping from the domain toward
the exit among 10 particles issued at the inlet. We confirm that
particles experience stagnant behavior near the exit of the rotating
blades where the centrifugal force acting on the particles is in balance
with the air drag force. It was also found that the minimum particle
size that can be separated by the machine with the rotor is determined
by its capability to stay at the outlet of the rotor channels.
Abstract: Information technology has been gaining more and
more space whether in industry, commerce or even for personal use,
but the misuse of it brings harm to the environment and human health
as a result. Contribute to the sustainability of the planet is to
compensate the environment, all or part of what withdraws it. The
green computing also came to propose practical for use in IT in an
environmentally correct way in aid of strategic management and
communication. This work focuses on showing how a mobile
application can help businesses reduce costs and reduced
environmental impacts caused by its processes, through a case study
of a public company in Brazil.
Abstract: This paper sets out a behavioral macro-model of a
Merged PiN and Schottky (MPS) diode based on silicon carbide
(SiC). This model holds good for both static and dynamic electrothermal
simulations for industrial applications. Its parameters have
been worked out from datasheets curves by drawing on the
optimization method: Simulated Annealing (SA) for the SiC MPS
diodes made available in the industry. The model also adopts the
Analog Behavioral Model (ABM) of PSPICE in which it has been
implemented. The thermal behavior of the devices was also taken
into consideration by making use of Foster’ canonical network as
figured out from electro-thermal measurement provided by the
manufacturer of the device.
Abstract: Background modeling and subtraction in video
analysis has been widely used as an effective method for moving
objects detection in many computer vision applications. Recently, a
large number of approaches have been developed to tackle different
types of challenges in this field. However, the dynamic background
and illumination variations are the most frequently occurred problems
in the practical situation. This paper presents a favorable two-layer
model based on codebook algorithm incorporated with local binary
pattern (LBP) texture measure, targeted for handling dynamic
background and illumination variation problems. More specifically,
the first layer is designed by block-based codebook combining with
LBP histogram and mean value of each RGB color channel. Because
of the invariance of the LBP features with respect to monotonic
gray-scale changes, this layer can produce block wise detection results
with considerable tolerance of illumination variations. The pixel-based
codebook is employed to reinforce the precision from the output of the
first layer which is to eliminate false positives further. As a result, the
proposed approach can greatly promote the accuracy under the
circumstances of dynamic background and illumination changes.
Experimental results on several popular background subtraction
datasets demonstrate very competitive performance compared to
previous models.
Abstract: Polymeric composites are being increasingly used as
repair material for repairing critical infrastructures such as building,
bridge, pressure vessel, piping and pipeline. Technique in repairing
damaged pipes is one of the major concerns of pipeline owners.
Considerable researches have been carried out on the repair of
corroded pipes using composite materials. This article attempts a
short review of the subject matter to provide insight into various
techniques used in repairing corroded pipes, focusing on a wide range
of composite repair systems. These systems including pre-cured
layered, flexible wet lay-up, pre-impregnated, split composite sleeve
and flexible tape systems. Both advantages and limitations of these
repair systems were highlighted. Critical technical aspects have been
discussed through the current standards and practices. Research gaps
and future study scopes in achieving more effective design
philosophy are also presented.
Abstract: This experimental study consists of a characterization
of epoxy grout where an amount of 2% of graphene nanoplatelets
particles were added to commercial epoxy resin to evaluate their
behavior regarding neat epoxy resin. Compressive tests, tensile tests
and flexural tests were conducted to study the effect of graphene
nanoplatelets on neat epoxy resin. By comparing graphene-based and
neat epoxy grout, there is no significant increase of strength due to
weak interface in the graphene nanoplatelets/epoxy composites.
From this experiment, the tension and flexural strength of graphenebased
epoxy grouts is slightly lower than ones of neat epoxy grout.
Nevertheless, the addition of graphene has produced more consistent
results according to a smaller standard deviation of strength.
Furthermore, the graphene has also improved the ductility of the
grout, hence reducing its brittle behaviour. This shows that the
performance of graphene-based grout is reliably predictable and able
to minimise sudden rupture. This is important since repair design of
damaged pipeline is of deterministic nature.
Abstract: Issues relating to the destructive phenomena that can
damage people and goods have returned to the centre of debate in
Italy with the increase in catastrophic episodes in recent years in a
country which is highly vulnerable to hydrological risk.
Environmental factors and geological and geomorphological
territorial characteristics play an important role in determining the
level of vulnerability and the natural tendency to risk. However, a
territory has also been subjected to the requirements of and
transformations of society and this brings other relevant factors. The
reasons for the increase in destructive phenomena are often to be
found in the territorial development models adopted. Stewardship of
the landscape and management of risk are related issues. This study aims to summarize the most relevant elements about
this connection and at the same time to clarify the role of
environmental risk assessment as a tool to aid in the sustainable
management of landscape. Finally, the study reflects on how regional
and urban planners deal with environmental risk and which aspects
should be monitored in order to adopt responsible and useful
interventions.
Abstract: Rapid developments in technology in the present age
have made it necessary for communities to follow technological
developments and adapt themselves to these developments. One of
the fields that are most rapidly affected by these developments is
undoubtedly education. Determination of the attitudes of preservice
teachers, who live in an age of technology and get ready to raise
future individuals, is of paramount importance both educationally and
professionally. The purpose of this study was to analyze attitudes of
preservice teachers towards technology and some variables that
predict these attitudes (gender, daily duration of internet use, and the
number of technical devices owned). 329 preservice teachers
attending the education faculty of a large university in central Turkey
participated, on a volunteer basis, in this study, where relational
survey model was used as the research method. Research findings
reveal that preservice teachers’ attitudes towards technology are
positive and at the same time, the attitudes of male preservice
teachers towards technology are more positive than their female
counterparts. As a result of the stepwise multiple regression analysis
where factors predicting preservice teachers’ attitudes towards
technology, it was found that duration of daily internet use was the
strongest predictor of attitudes towards technology.
Abstract: The aim of this work is to study the numerical
implementation of the Hilbert Uniqueness Method for the exact
boundary controllability of Euler-Bernoulli beam equation. This study
may be difficult. This will depend on the problem under consideration
(geometry, control and dimension) and the numerical method used.
Knowledge of the asymptotic behaviour of the control governing the
system at time T may be useful for its calculation. This idea will
be developed in this study. We have characterized as a first step, the
solution by a minimization principle and proposed secondly a method
for its resolution to approximate the control steering the considered
system to rest at time T.
Abstract: Contemporary metropolitan areas and large cities are
dynamic, rapidly growing and continuously changing. Thus, urban
transformations and mutations are not a new phenomenon, but rather
a continuous process. Basic factors of urban transformation are
related to development of technologies, globalisation, lifestyle, etc.,
which in combination with local factors have generated an extremely
great variety of urban development conditions. This article discusses
the main urbanisation processes in Lithuania during last 50-year
period and social factors affecting urban functional mutations.
Abstract: The need to protect our cultural heritage was stressed
on revitalization of historical city centers in communities. The main
aim of this research is to attract finance and activities to the historical
city centers through the citizens and municipalities participation
while cities expanded their boundaries toward suburban areas. Today
the main problems which facing to the most historical city centers, is
loss of their centrality through effect of urbanization on any point of
the cities which is the most important issue on neglect and
abandonment of the historical central area by decentralizing living,
commerce and public areas. This article evaluate the ways in which
city center revitalization can be effect on vitality and viability of the
central area in case of Naghshe Jahan square which situated at the
center of Isfahan city, Iran. Constructed between 1598 and 1629, it is
now an important historical site, and one of UNESCO's World
Heritage Sites.
Abstract: The purpose of this study is to analyze the temporal
and spatial variability of thermal conditions in the Republic of
Armenia. The paper describes annual fluctuations in air temperature.
Research has been focused on case study region of Armenia and
surrounding areas, where long–term measurements and observations
of weather conditions have been performed within the National
Meteorological Service of Armenia and its surrounding areas. The
study contains yearly air temperature data recorded between 1961-
2012. Mann-Kendal test and the autocorrelation function were
applied to detect the change trend of annual mean temperature, as
well as other parametric and non-parametric tests searching to find
the presence of some breaks in the long term evolution of
temperature. The analysis of all records reveals a tendency mostly
towards warmer years, with increased temperatures especially in
valleys and inner basins. The maximum temperature increase is up to
1,5°C. Negative results have not been observed in Armenia. The
patterns of temperature change have been observed since the 1990’s
over much of the Armenian territory. The climate in Armenia was
influenced by global change in the last 2 decades, as results from the
methods employed within the study.
Abstract: This first-attempt study revealed that decolorized
intermediates of azo dyes could act as redox mediators to assist
wastewater (WW) decolorization due to enhancement of
electron-transport phenomena. Electrochemical impedance spectra
indicated that hydroxyl and amino-substituent(s) were functional
group(s) as redox-mediator(s). As azo dyes are usually multiple
benzene-rings structured, their derived decolorized intermediates are
likely to play roles of electron shuttles due to lower barrier of energy
gap for electron shuttling. According to cyclic voltammetric profiles,
redox mediating characteristics of decolorized intermediates of azo
dyes (e.g., RBu171, RR198, RR141, RBk5) were clearly disclosed.
With supplementation of biodecolorized metabolites of RR141 and
198, decolorization performance of could be evidently augmented.
This study also suggested the optimal modes of microbial fuel cell
(MFC)-assisted WW decolorization would be plug-flow or batch
mode of operation with no mix. Single chamber-MFCs would be more
favourable than double chamber MFCs due to non-mixing contacting
reactor scheme for operation.
Abstract: River Hindon is an important river catering the
demand of highly populated rural and industrial cluster of western
Uttar Pradesh, India. Water quality of river Hindon is deteriorating at
an alarming rate due to various industrial, municipal and agricultural
activities. The present study aimed at identifying the pollution
sources and quantifying the degree to which these sources are
responsible for the deteriorating water quality of the river. Various
water quality parameters, like pH, temperature, electrical
conductivity, total dissolved solids, total hardness, calcium, chloride,
nitrate, sulphate, biological oxygen demand, chemical oxygen
demand, and total alkalinity were assessed. Water quality data
obtained from eight study sites for one year has been subjected to the
two multivariate techniques, namely, principal component analysis
and cluster analysis. Principal component analysis was applied with
the aim to find out spatial variability and to identify the sources
responsible for the water quality of the river. Three Varifactors were
obtained after varimax rotation of initial principal components using
principal component analysis. Cluster analysis was carried out to
classify sampling stations of certain similarity, which grouped eight
different sites into two clusters. The study reveals that the
anthropogenic influence (municipal, industrial, waste water and
agricultural runoff) was the major source of river water pollution.
Thus, this study illustrates the utility of multivariate statistical
techniques for analysis and elucidation of multifaceted data sets,
recognition of pollution sources/factors and understanding
temporal/spatial variations in water quality for effective river water
quality management.
Abstract: Over the last two decades, externally bonded fiber
reinforced polymer (FRP) composites bonded to concrete substrates
has become a popular method for strengthening reinforced concrete
(RC) highway and railway bridges. Such structures are exposed to
severe cyclic loading throughout their lifetime often resulting in
fatigue damage to structural components and a reduction in the
service life of the structure. Since experimental and numerical results
on the fatigue performance of FRP-to-concrete joints are still limited,
the current research focuses on assessing the fatigue performance of
externally bonded FRP-to-concrete joints using a direct shear test.
Some early results indicate that the stress ratio and the applied cyclic
stress level have a direct influence on the fatigue life of the externally
bonded FRP. In addition, a calibrated finite element model is
developed to provide further insight into the influence of certain
parameters such as: concrete strength, FRP thickness, number of
cycles, frequency, and stiffness on the fatigue life of the FRP-toconcrete
joints.
Abstract: In the present work, forming limit diagrams and strain
distribution profile diagrams for extra deep drawing steel at room and
elevated temperatures have been determined experimentally by
conducting stretch forming experiments by using designed and
fabricated warm stretchforming tooling setup. With the help of
forming Limit Diagrams (FLDs) and strain, distribution profile
diagrams the formability of Extra Deep Drawing steel has been
analyzed and co-related with mechanical properties like strain
hardening COEFFICIENT (n) and normal anisotropy (r−). Mechanical
properties of EDD steel from room temperature to 4500C were
determined and discussed the impact of temperature on the properties
like work hardening exponent (n) anisotropy (r-) and strength
coefficient of the material. In addition, the fractured surfaces after
stretching have undergone the some metallurgical investigations and
attempt has been made to co-relate with the formability of EDD steel
sheets. They are co-related and good agreement with FLDs at various
temperatures.
Abstract: A physical model for guiding the wave in
photorefractive media is studied. Propagation of cos-Gaussian beam
as the special cases of sinusoidal-Gaussian beams in photorefractive
crystal is simulated numerically by the Crank-Nicolson method in
one dimension. Results show that the beam profile deforms as the
energy transfers from the center to the tails under propagation. This
simulation approach is of significant interest for application in optical
telecommunication. The results are presented graphically and
discussed.