Abstract: This paper aims to analysis the behavior of DC corona
discharge in wire-to-plate electrostatic precipitators (ESP). Currentvoltage
curves are particularly analyzed. Experimental results show
that discharge current is strongly affected by the applied voltage. The proposed method of current identification is to use the method
of least squares. Least squares problems that of into two categories:
linear or ordinary least squares and non-linear least squares,
depending on whether or not the residuals are linear in all unknowns.
The linear least-squares problem occurs in statistical regression
analysis; it has a closed-form solution. A closed-form solution (or
closed form expression) is any formula that can be evaluated in a
finite number of standard operations. The non-linear problem has no
closed-form solution and is usually solved by iterative.
Abstract: Objective: Safety and efficacy of Ahmed glaucoma
valve implantation for the management of uveitis induced glaucoma
evaluated on the five dogs with uncontrollable glaucoma. Materials
and Methods: Ahmed Glaucoma Valve (AGV®; New World
Medical, Rancho Cucamonga, CA, USA) is a flow restrictive, nonobstructive
self-regulating valve system. Preoperative ocular
evaluation included direct ophthalmoscopy and measurement of the
intraocular pressure (IOP). The implant was examined and primed
prior to implantation. The selected site of the valve implantation was
the superior quadrant between the superior and lateral rectus muscles.
A fornix-based incision was made through the conjunectiva and
Tenon’s capsule. A pocket is formed by blunt dissection of Tenon’s
capsule from the episclera. The body of the implant was inserted into
the pocket with the leading edge of the device around 8-10 mm from
the limbus. Results: No post-operative complications were detected
in the operated eyes except a persistent corneal edema occupied the
upper half of the cornea in one case. Hyphaema was very mild and
seen only in two cases which resolved quickly two days after surgery.
Endoscopical evaluation for the operated eyes revealed a normal
ocular fundus with clearly visible optic papilla, tapetum and retinal
blood vessels. No evidence of hemorrhage, infection, adhesions or
retinal abnormalities was detected. Conclusion: Ahmed glaucoma
valve is safe and effective implant for treatment of uveitic glaucoma
in dogs.
Abstract: With the advancement of knowledge about the utility
and impact of sustainability, its feasibility has been explored into
different walks of life. Scientists, however; have established their
knowledge in four areas viz environmental, economic, social and
cultural, popularly termed as four pillars of sustainability. Aspects of
environmental and economic sustainability have been rigorously
researched and practiced and huge volume of strong evidence of
effectiveness has been founded for these two sub-areas. For the social
and cultural aspects of sustainability, dependable evidence of
effectiveness is still to be instituted as the researchers and
practitioners are developing and experimenting methods across the
globe. Therefore, the present research aimed to identify globally used
practices of social and cultural sustainability and through evidence
synthesis assess their outcomes to determine the effectiveness of
those practices. A PICO format steered the methodology which
included all populations, popular sustainability practices including
walkability/cycle tracks, social/recreational spaces, privacy, health &
human services and barrier free built environment, comparators
included ‘Before’ and ‘After’, ‘With’ and ‘Without’, ‘More’ and
‘Less’ and outcomes included Social well-being, cultural coexistence,
quality of life, ethics and morality, social capital, sense of
place, education, health, recreation and leisure, and holistic
development. Search of literature included major electronic
databases, search websites, organizational resources, directory of
open access journals and subscribed journals. Grey literature,
however, was not included. Inclusion criteria filtered studies on the
basis of research designs such as total randomization, quasirandomization,
cluster randomization, observational or single studies
and certain types of analysis. Studies with combined outcomes were
considered but studies focusing only on environmental and/or
economic outcomes were rejected. Data extraction, critical appraisal
and evidence synthesis was carried out using customized tabulation,
reference manager and CASP tool. Partial meta-analysis was carried
out and calculation of pooled effects and forest plotting were done.
As many as 13 studies finally included for final synthesis explained
the impact of targeted practices on health, behavioural and social
dimensions. Objectivity in the measurement of health outcomes
facilitated quantitative synthesis of studies which highlighted the
impact of sustainability methods on physical activity, Body Mass
Index, perinatal outcomes and child health. Studies synthesized
qualitatively (and also quantitatively) showed outcomes such as
routines, family relations, citizenship, trust in relationships, social
inclusion, neighbourhood social capital, wellbeing, habitability and
family’s social processes. The synthesized evidence indicates slight
effectiveness and efficacy of social and cultural sustainability on the
targeted outcomes. Further synthesis revealed that such results of this
study are due weak research designs and disintegrated implementations. If architects and other practitioners deliver their
interventions in collaboration with research bodies and policy
makers, a stronger evidence-base in this area could be generated.
Abstract: Despite the wide spread use of synthetic dyes, natural
dyes are still exploited and used to enhance its inherent aesthetic
qualities as a major material for beautification of the body. Centuries
before the discovery of synthetic dyes, natural dyes were the only
source of dye open to mankind. Dyes are extracted from plant -
leaves, roots and barks, insect secretions, and minerals. However,
research findings have made it clear that of all, plants- leaves, roots,
barks or flowers are the most explored and exploited in which henna
(Lawsonia innermis L.) is one of those plants. Experiment has also
shown that henna is used in body painting in conjunction with an
alkaline (Ammonium Sulphate) as a fixing agent. This of course
gives a clue that if colour derived from henna is properly
investigated, it may not only be used for body decoration but
possibly, may have affinity to fiber substrate. This paper investigates
the dyeing potentials – dye ability and fastness qualities of henna dye
extracts on cotton and linen fibers using mordants like ammonium
sulphate and other alkalis (hydrosulphate and caustic soda, potash,
common salt, potassium alum). Hot and cold water and ethanol
solvent were used in the extraction of the dye to investigate the most
effective method, dye ability, and fastness qualities of these extracts
under room temperature. The results of the experiment show that
cotton have a high rate of dye intake than other fiber. On a similar
note, the colours obtained depend most on the solvent used. In
conclusion, hot water extraction appears more effective. While the
colours obtained from ethanol and both cold hot methods of
extraction range from light to dark yellow, light green to army green
and to some extent shades of brown hues.
Abstract: Success means different things for different people.
For us, project managers, it becomes even harder to actually find a
definition. Many factors have to be included in the evaluation.
Moreover, literature is not very helpful, lacking consensus and
neutrality. Post-implementation reviews (PIR) can be an efficient tool
in evaluating how things worked on a certain project. Despite the
visible progress, PIR is not a very detailed subject yet and there is not
common understanding in this matter. This may be the reason that
some organizations include it in the projects’ lifecycle and some do
not. Through this paper, we point out the reasons why all project
managers should pay proper attention to this important step and to the
elements which can be assessed, beside the already famous triple
constraints: cost, budget and time. It is essential to take notice that PIR is not a checklist. It brings the
edge in eliminating subjectivity and judging projects based on actual
proof. Based on our experience, our success indicator model,
presented in this paper, contributes to the success of the project! In
the same time, it increases trust among customers who will perceive
success more objectively.
Abstract: The nutritional composition and hypoglycaemic effect
of crackers produced from blend of sprouted pigeon pea, unripe
plantain and brewers’ spent grain and fed to Alloxan induced diabetic
rat was investigated. Crackers were produced from different blends of
sprouted pigeon pea, unripe plantain and brewers’ spent grain. The
crackers were evaluated for proximate composition, amino acid
profile and antinutritional factors. Blood glucose levels of normal and
diabetic rats fed with the control sample and different formulations of
cracker were measured. The protein content of the samples were
significantly different (p
Abstract: Journal bearings used in IC engines are prone to premature
failures and are likely to fail earlier than the rated life due to
highly impulsive and unstable operating conditions and frequent
starts/stops. Vibration signature extraction and wear debris analysis
techniques are prevalent in industry for condition monitoring of
rotary machinery. However, both techniques involve a great deal of
technical expertise, time, and cost. Limited literature is available on
the application of these techniques for fault detection in reciprocating
machinery, due to the complex nature of impact forces that
confounds the extraction of fault signals for vibration-based analysis
and wear prediction. In present study, a simulation model was developed to investigate
the bearing wear behaviour, resulting because of different operating
conditions, to complement the vibration analysis. In current
simulation, the dynamics of the engine was established first, based on
which the hydrodynamic journal bearing forces were evaluated by
numerical solution of the Reynold’s equation. In addition, the
essential outputs of interest in this study, critical to determine wear
rates are the tangential velocity and oil film thickness between the
journals and bearing sleeve, which if not maintained appropriately,
have a detrimental effect on the bearing performance. Archard’s wear prediction model was used in the simulation to
calculate the wear rate of bearings with specific location information
as all determinative parameters were obtained with reference to crank
rotation. Oil film thickness obtained from the model was used as a
criterion to determine if the lubrication is sufficient to prevent contact
between the journal and bearing thus causing accelerated wear. A
limiting value of 1 μm was used as the minimum oil film thickness
needed to prevent contact. The increased wear rate with growing
severity of operating conditions is analogous and comparable to the
rise in amplitude of the squared envelope of the referenced vibration
signals. Thus on one hand, the developed model demonstrated its
capability to explain wear behaviour and on the other hand it also
helps to establish a co-relation between wear based and vibration
based analysis. Therefore, the model provides a cost effective and
quick approach to predict the impending wear in IC engine bearings
under various operating conditions.
Abstract: In wireless sensor network, sensor node transmits the
sensed data to the sink node in multi-hop communication
periodically. This high traffic induces congestion at the node which is
present one-hop distance to the sink node. The packet transmission
and reception rate of these nodes should be very high, when
compared to other sensor nodes in the network. Therefore, the energy
consumption of that node is very high and this effect is known as the
“funneling effect”. The tree based-data aggregation technique
(TBDA) is used to reduce the energy consumption of the node. The
throughput of the overall performance shows a considerable decrease
in the number of packet transmissions to the sink node. The proposed
scheme, TBDA, avoids the funneling effect and extends the lifetime
of the wireless sensor network. The average case time complexity for
inserting the node in the tree is O(n log n) and for the worst case time
complexity is O(n2).
Abstract: Searching the “Island of stability” is a topic of
extreme interest in theoretical as well as experimental modern
physics today. This “island of stability” is spanned by superheavy
elements (SHE's) that are produced in the laboratory. SHE's are
believed to exist primarily due to the “magic” stabilizing effects of
nuclear shell structure. SHE synthesis is extremely difficult due to
their very low production cross section, often of the order of pico
barns or less. Stabilizing effects of shell closures at proton number
Z=82 and neutron number N=126 are predicted theoretically. Though
stabilizing effects of Z=82 have been experimentally verified, no
concluding observations have been made with N=126, so far. We
measured and analyzed the total evaporation residue (ER) cross
sections for a number of systems with neutron number around 126 to
explore possible shell closure effects in ER cross sections, in this
work.
Abstract: Maintenance and design engineers have great concern
for the functioning of rotating machineries due to the vibration
phenomenon. Improper functioning in rotating machinery originates
from the damage to rolling element bearings. The status of rolling
element bearings require advanced technologies to monitor their
health status efficiently and effectively. Avoiding vibration during
machine running conditions is a complicated process. Vibration
simulation should be carried out using suitable sensors/ transducers to
recognize the level of damage on bearing during machine operating
conditions. Various issues arising in rotating systems are interlinked
with bearing faults. This paper presents an approach for fault
diagnosis of bearings using neural networks and time/frequencydomain
vibration analysis.
Abstract: The occurrences of precipitation, also commonly
referred as rain, in the form of "convective" and "stratiform" have
been identified to exist worldwide. In this study, the radar return
echoes or known as reflectivity values acquired from radar scans
have been exploited in the process of classifying the type of rain
endured. The investigation use radar data from Malaysian
Meteorology Department (MMD). It is possible to discriminate the
types of rain experienced in tropical region by observing the vertical
characteristics of the rain structure. .Heavy rain in tropical region
profoundly affects radiowave signals, causing transmission
interference and signal fading. Required wireless system fade margin
depends on the type of rain. Information relating to the two
mentioned types of rain is critical for the system engineers and
researchers in their endeavour to improve the reliability of
communication links. This paper highlights the quantification of
percentage occurrences over one year period in 2009.
Abstract: In this study, Brillouin Gain Spectrum (BGS) is
experimentally analyzed in the Brillouin Optical Time Domain
Reflectometry (BOTDR) and Brillouin Optical Time Domain
Analyzer (BOTDA). For this purpose, the signal level of the
microwave generator is varied and the effects of BGS are
investigated. In the setups, 20 km conventional single mode fiber is
used to both setups and laser wavelengths are selected around 1550
nm. To achieve best results, it can be used between 5 dBm to 15 dBm
signal level of microwave generator for BOTDA and BOTDR setups.
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: 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: The major environmental risk of soil pollution is the
contamination of groundwater by infiltration of organic and inorganic
pollutants which can cause a serious menace. To prevent this risk and
to protect the groundwater, we proceeded in this study to test the
reliability of a biosolid as barrier to prevent the migration of very
dangerous pollutants as ‘Cadmium’ through the different soil layers. In this study, we tried to highlight the effect of several parameters
such as: turbidity (different cycle of Hydration/Dehydration),
rainfall, effect of initial Cd(II) concentration and the type of soil.
These parameters allow us to find the most effective manner to
integrate this barrier in the soil. From the results obtained, we found a
significant effect of the barrier. Indeed, the recorded passing
quantities are lowest for the highest rainfall; we noted also that the
barrier has a better affinity towards higher concentrations; the most
retained amounts of cadmium has been in the top layer of the two
types of soil tested, while the lowest amounts of cadmium are
recorded in the bottom layers of soils.
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.