Abstract: Wavelength Division Multiplexing (WDM)
technology is the most promising technology for the proper
utilization of huge raw bandwidth provided by an optical fiber. One
of the key problems in implementing the all-optical WDM network is
the packet contention. This problem can be solved by several
different techniques. In time domain approach the packet contention
can be reduced by incorporating Fiber Delay Lines (FDLs) as optical
buffer in the switch architecture. Different types of buffering
architectures are reported in literatures. In the present paper a
comparative performance analysis of three most popular FDL
architectures are presented in order to obtain the best contention
resolution performance. The analysis is further extended to consider
the effect of different fiber non-linearities on the network
performance.
Abstract: Carbon dioxide is one of the major greenhouse gas
(GHG) contributors. It is an obligation of the industry to reduce the
amount of carbon dioxide emission to the acceptable limits.
Tremendous research and studies are reported in the past and still the
quest to find the suitable and economical solution of this problem
needed to be explored in order to develop the most plausible absorber
for carbon dioxide removal. Amino acids can be potential alternate
solvents for carbon dioxide capture from gaseous streams. This is due
to its ability to resist oxidative degradation, low volatility and its
ionic structure. In addition, the introduction of promoter-like
piperazine to amino acid helps to further enhance the solubility. In
this work, the effect of piperazine on thermo physical properties and
solubility of β-Alanine aqueous solutions were studied for various
concentrations. The measured physicochemical properties data was
correlated as a function of temperature using least-squares method
and the correlation parameters are reported together with it respective
standard deviations. The effect of activator piperazine on the CO2
loading performance of selected amino acid under high-pressure
conditions (1bar to 10bar) at temperature range of (30 to 60)oC was
also studied. Solubility of CO2 decreases with increasing temperature
and increases with increasing pressure. Quadratic representation of
solubility using Response Surface Methodology (RSM) shows that
the most important parameter to optimize solubility is system
pressure. The addition of promoter increases the solubility effect of
the solvent.
Abstract: A broadband wire monopole antenna loaded by inhomogeneous stack of annular dielectric ring resonators (DRRs) is proposed. The proposed antenna exhibits a broad impedance bandwidth from 3 to 30 GHz. This is achieved by adding an external step matching network at the antenna feed point. The matching network is comprised of three annular DRRs possessing different permittivity values and sharing the same axial over a finite ground plane. The antenna performance is characterized using full-wave EM simulation. Compared to previous-reported wire antennas with improved bandwidth achieved by DRRs, the proposed topology provides relatively compact realization and superior broadband performance.
Abstract: This report examines the current state of human gait
simulator development based on the human hip joint model. This unit
will create a database of human gait types, useful for setting up and
calibrating Mechano devices, as well as the creation of new systems
of rehabilitation, exoskeletons and walking robots. The system has
many opportunities to configure the dimensions and stiffness, while
maintaining relative simplicity.
Abstract: Inspired by the Formula-1 competition, IMechE
(Institute of Mechanical Engineers) and Formula SAE (Society of
Mechanical Engineers) organize annual competitions for University
and College students worldwide to compete with a single-seat racecar
they have designed and built. Design of the chassis or the frame is a
key component of the competition because the weight and stiffness
properties are directly related with the performance of the car and the
safety of the driver. In addition, a reduced weight of the chassis has
direct influence on the design of other components in the car. Among
others, it improves the power to weight ratio and the aerodynamic
performance. As the power output of the engine or the battery
installed in the car is limited to 80 kW, increasing the power to
weight ratio demands reduction of the weight of the chassis, which
represents the major part of the weight of the car. In order to reduce
the weight of the car, ION Racing team from University of
Stavanger, Norway, opted for a monocoque design. To ensure
fulfilment of the competition requirements of the chassis, the
monocoque design should provide sufficient torsional stiffness and
absorb the impact energy in case of possible collision. The study reported in this article is based on the requirements for
Formula Student competition. As part of this study, diverse
mechanical tests were conducted to determine the mechanical
properties and performances of the monocoque design. Upon a
comprehensive theoretical study of the mechanical properties of
sandwich composite materials and the requirements of monocoque
design in the competition rules, diverse tests were conducted
including 3-point bending test, perimeter shear test and test for
absorbed energy. The test panels were homemade and prepared with
equivalent size of the side impact zone of the monocoque, i.e. 275
mm x 500 mm, so that the obtained results from the tests can be
representative. Different layups of the test panels with identical core
material and the same number of layers of carbon fibre were tested
and compared. Influence of the core material thickness was also
studied. Furthermore, analytical calculations and numerical analysis
were conducted to check compliance to the stated rules for Structural
Equivalency with steel grade SAE/AISI 1010. The test results were
also compared with calculated results with respect to bending and
torsional stiffness, energy absorption, buckling, etc. The obtained results demonstrate that the material composition
and strength of the composite material selected for the monocoque
design has equivalent structural properties as a welded frame and thus
comply with the competition requirements. The developed analytical
calculation algorithms and relations will be useful for future
monocoque designs with different lay-ups and compositions.
Abstract: Rivers have transient storage or dead zones where
injected pollutants or solutes are entrapped for considerable period of
time, known as residence time, before being released into the main
flowing zones of rivers. In this study, a new empirical expression for
residence time, implementing genetic programming on published
dispersion data, has been derived. The proposed expression uses few
hydraulic and geometric characteristics of rivers which are normally
known to the authorities. When compared with some reported
expressions, based on various statistical indices, it can be concluded
that the proposed expression predicts the residence time of pollutants
in natural rivers more accurately.
Abstract: Both steady and unsteady turbulent mixed convection
heat transfer in a 3D lid-driven enclosure, which has constant heat
flux on the middle of bottom wall and with isothermal moving
sidewalls, is reported in this paper for working fluid with Prandtl
number Pr = 0.71. The other walls are adiabatic and stationary. The
dimensionless parameters used in this research are Reynolds number,
Re = 5000, 10000 and 15000, and Richardson number, Ri = 1 and 10.
The simulations have been done by using different turbulent methods
such as RANS, URANS, and LES. The effects of using different k-ε
models such as standard, RNG and Realizable k-ε model are
investigated. Interesting behaviours of the thermal and flow fields
with changing the Re or Ri numbers are observed. Isotherm and
turbulent kinetic energy distributions and variation of local Nusselt
number at the hot bottom wall are studied as well. The local Nusselt
number is found increasing with increasing either Re or Ri number.
In addition, the turbulent kinetic energy is discernibly affected by
increasing Re number. Moreover, the LES results have shown good
ability of this method in predicting more detailed flow structures in
the cavity.
Abstract: The aim of this paper is to propose a general
framework for storing, analyzing, and extracting knowledge from
two-dimensional echocardiographic images, color Doppler images,
non-medical images, and general data sets. A number of high
performance data mining algorithms have been used to carry out this
task. Our framework encompasses four layers namely physical
storage, object identification, knowledge discovery, user level.
Techniques such as active contour model to identify the cardiac
chambers, pixel classification to segment the color Doppler echo
image, universal model for image retrieval, Bayesian method for
classification, parallel algorithms for image segmentation, etc., were
employed. Using the feature vector database that have been
efficiently constructed, one can perform various data mining tasks
like clustering, classification, etc. with efficient algorithms along
with image mining given a query image. All these facilities are
included in the framework that is supported by state-of-the-art user
interface (UI). The algorithms were tested with actual patient data
and Coral image database and the results show that their performance
is better than the results reported already.
Abstract: The end panels of a large rectangular industrial duct,
which experience significant internal pressures, also experience
considerable transverse shear due to transfer of gravity loads to the
supports. The current design practice of such thin plate panels for
shear load is based on methods used for the design of plate girder
webs. The structural arrangements, the loadings and the resulting
behavior associated with the industrial duct end panels are, however,
significantly different from those of the web of a plate girder. The
large aspect ratio of the end panels gives rise to multiple bands of
tension fields, whereas the plate girder web design is based on one
tension field. In addition to shear, the industrial end panels are
subjected to internal pressure which in turn produces significant
membrane action. This paper reports a study which was undertaken
to review the current industrial analysis and design methods and to
propose a comprehensive method of designing industrial duct end
panels for shear resistance. In this investigation, a nonlinear finite element model was
developed to simulate the behavior of industrial duct end panel, along
with the associated edge stiffeners, subjected to transverse shear and
internal pressures. The model considered the geometric imperfections
and constitutive relations for steels. Six scale independent
dimensionless parameters that govern the behavior of such end panel
were identified and were then used in a parametric study. It was
concluded that the plate slenderness dominates the shear strength of
stockier end panels, and whereas, both the plate slenderness and the
aspect ratio influence the shear strength of slender end panels. Based
on these studies, this paper proposes design aids for estimating the
shear strength of rectangular duct end panels.
Abstract: Agricultural machinery industry plays an important
role in the industrial development especially the production industry
of the country. There has been continuing development responding to
the higher demand of the production. However, the problem in
agricultural machinery production still exists. Thus, the purpose of
this research is to investigate problems on fundamental factors of
industry based on the entrepreneurs’ point of view. The focus was on
the small and medium size industry receiving factory license type
number 0660 from the Department of Industrial Works. The
investigation was on the comparison between the management of the
small and medium size agricultural industry in 3 provinces in the
central region of Thailand. Population in this study consisted of 189
company managers or managing directors, of which 101 were from
the small size and 88 were from the medium size industry. The data
were analyzed to find percentage, arithmetic mean, and standard
deviation with independent sample T-test at the statistical
significance .05. The results showed that the small and medium size
agricultural machinery manufacturers in the central region of
Thailand reported high problems in every aspect. When compared the
problems on basic factors in running the business, it was found that
there was no statistically difference at .05 in managing of the small
and medium size agricultural machinery manufacturers. However,
there was a statistically significant difference between the small and
medium size agricultural machinery manufacturers on the aspect of
policy and services of the government. The problems reported by the
small and medium size agricultural machinery manufacturers were
the services on public tap water and the problem on politic and
stability of the country.
Abstract: Rotary entrainment is a phenomenon in which the
interface of two immiscible fluids are subjected to external flux by
means of rotation. Present work reports the experimental study on
rotary motion of a horizontal cylinder between the interface of air and
water to observe the penetration of gas inside the liquid. Experiments
have been performed to establish entrainment of air mass in water
alongside the cylindrical surface. The movement of tracer and seeded
particles has been tracked to calculate the speed and path of the
entrained air inside water. Simplified particle image velocimetry
technique has been used to trace the movement of particles/tracers at
the moment they are injected inside the entrainment zone and
suspended beads have been used to replicate the particle movement
with respect to time in order to determine the flow dynamics of the
fluid along the cylinder. Present paper establishes a thorough experimental analysis of the
rotary entrainment phenomenon between air and water keeping in
interest the extent to which we can intermix the two and also to study
its entrainment trajectories.
Abstract: In this paper, we have reported birefringence
manipulation in regenerated high birefringent fiber Bragg grating
(RPMG) by using CO2 laser annealing method. The results indicate
that the birefringence of RPMG remains unchanged after CO2 laser
annealing followed by slow cooling process, but reduced after fast
cooling process (~5.6×10-5). After a series of annealing procedures
with different cooling rates, the obtained results show that slower the
cooling rate, higher the birefringence of RPMG. The volume, thermal
expansion coefficient (TEC) and glass transition temperature (Tg)
change of stress applying part in RPMG during cooling process are
responsible for the birefringence change. Therefore, these findings
are important to the RPMG sensor in high and dynamic temperature
environment. The measuring accuracy, range and sensitivity of
RPMG sensor is greatly affected by its birefringence value. This
work also opens up a new application of CO2 laser for fiber annealing
and birefringence modification.
Abstract: This study investigates the influence of low
temperature thermo-chemical pretreatment of organic food waste on
performance of COD solubilisation. Both temperature and alkaline
agent were reported to have effect on solubilizing any possible
biomass including organic food waste. The three independent
variables considered in this pretreatment were temperature (50-90oC),
pretreatment time (30-120 minutes) and alkaline concentration,
sodium hydroxide, NaOH (0.7-15 g/L). The maximal condition
obtained were 90oC, 15 g/L NaOH for 2 hours. Solubilisation has
potential in enhancing methane production by providing high amount
of soluble components at early stage during anaerobic digestion.
Abstract: The report deals with comparison of traffic accidents
in Slovak republic in road and rail transport since 2009 until 2014,
with evaluation of external costs and consequently with the
possibilities of their internalization. The results of road traffic
accidents analysis are realized in line with after-effects they have
caused; in line with main cause, place of origin (within or out of
town) and in accordance to age of accident´s victims and kind of
injuries (easy, hard or fatal). Evaluation of individual after-effects is
carried in terms of probability of traffic accidents occurrence.
Abstract: Lagos urban mini bus drivers play a critical role in the
transportation sector. The current major mode of transportation
within Lagos metropolis remains road transportation and this
confirms the relevance of urban mini-bus drivers in transporting the
populace to their various destinations. Other modes of transportation
such as the train and waterways are currently inadequate. Various
threats to the well-being of urban bus drivers include congested
traffic typical of modern day lifestyles, dwindling financial returns
due to long hours in traffic, fewer hours of sleep, inadequate diet,
time pressure, and assaults related to fare disputes. Several healthrelated
problems have been documented to be associated with urban
bus driving. For instance, greater rates of hypertension, obesity and
cholesterol level have been reported. Research studies are yet to
identify the influence of age and marital status on the well-being of
urban mini-bus drivers in Lagos metropolis. A study of this nature is
necessary as it is culturally perceived in Nigeria that older and
married people are especially influenced by family affiliation and
would behave in ways that would project positive outcomes. The
study sample consisted of 150 urban mini-bus drivers who were
conveniently sampled from six (6) different terminuses where their
journey begins and terminates. The well-being questionnaire was
administered to participants. The criteria for inclusion in the study
included the ability to read in English language and the confirmation
that interested participants were on duty and suited to be driving
mini-buses. Due to the nature of the job of bus driving, the researcher
administered the questionnaires on participants who were free and
willing to respond to the survey. All participants were males of
various age groups and of different marital statuses. Results of
analyses conducted revealed no significant influence of age and
marital status on the well-being of urban mini-bus drivers. This
indicates that the well-being of urban mini bus drivers is not
influenced by age or marital status. The findings of this study have
cultural implications. It negates the popularly held belief that older
and married people care more about their well-being than younger
and single people. It brings to fore the need to also identify and
consider other factors when certifying people for the job of urban bus
driving.
Abstract: Sub-Saharan Africa is described as the second fastest
growing in mobile phone penetration in the world more than in the
United States or the European Union. Mobile phones have been used
to provide a lot of opportunities to improve people’s lives in the
region such as in banking, marketing, entertainment, and paying for
various bills such as water, TV, and electricity. However, the
potential of mobile phones to enhance teaching and learning has not
been explored. This study presents an experience of developing and
delivering SMS based quiz questions used to assess mastery of
subject content knowledge of science and mathematics secondary
school teachers in Tanzania. The SMS quizzes were used as a follow
up support mechanism to 500 teachers who participated in a project
to upgrade subject content knowledge of teachers in science and
mathematics subjects in Tanzania. Quizzes of 10-15 questions were
sent to teachers each week for 8 weeks and the results were analyzed
using SPSS. Results show that teachers who participated in chemistry
and biology subjects have better performance compared to those who
participated in mathematics and physics subjects. Teachers reported
some challenges that led to poor performance, This research has
several practical implications for those who are implementing or
planning to use mobile phones in teaching and learning especially in
rural secondary schools in sub-Saharan Africa.
Abstract: Local steel slag is produced as a by-product during the
oxidation of steel pellets in an electric arc furnace. Using local steel
slag waste as a hundred substitutes of crashed stone in construction
materials would resolve the environmental problems caused by the
large-scale depletion of the natural sources of crashed stone. This
paper reports the experimental study to investigate the influence of a
hundred replacement of crashed stone as a coarse aggregate with
local steel slag, on the fresh and hardened geopolymer concrete
properties. The investigation includes traditional testing of hardening
concrete, for selected mixes of cement and geopolymer concrete. It
was found that local steel slag as a coarse aggregate enhanced the
slump test of the fresh state of cement and geopolymer concretes.
Nevertheless, the unit weight of concretes was affected. Meanwhile,
the good performance was observed when fly ash used as geopolymer
concrete based.
Abstract: Background: Maintaining the correct body balance is
essential in the prevention of falls in the elderly, which is especially
important for women because of postmenopausal osteoporosis and
the serious consequences of falls. One of the exercise methods which
is very popular among adults, and which may affect body balance in
the positive way is the Pilates method. The aim of the study was to
evaluate the effect of regular Pilates exercises on the ability to
maintain body balance in static conditions in adult healthy women.
Material and methods: The study group consisted of 20 healthy
women attending Pilates twice a week for at least 1 year. The control
group consisted of 20 healthy women physically inactive. Women in
the age range from 35 to 50 years old without pain in musculoskeletal
system or other pain were only qualified to the groups. Body balance
was assessed using MatScan VersaTek platform with Sway Analysis
Module based on Matscan Clinical 6.7 software (Tekscan Inc.,
U.S.A). The balance was evaluated under the following conditions:
standing on both feet with eyes open, standing on both feet with eyes
closed, one-leg standing (separately on the right and left foot) with
eyes open. Each test lasted 30 seconds. The following parameters
were calculated: estimated size of the ellipse of 95% confidence, the
distance covered by the Center of Gravity (COG), the size of the
maximum shift in the sagittal and frontal planes and load distribution
between the left and right foot, as well as between rear- and forefoot.
Results: It was found that there is significant difference between the
groups in favor of the study group in the size of the confidence
ellipse and maximum shifts of COG in the sagittal plane during
standing on both feet, both with the eyes open and closed (p
Abstract: In this study, static and dynamic responses of a typical
reinforced concrete solid slab, designed to British Standard (BS 8110:
1997) and under self and live loadings for dance halls are reported.
Linear perturbation analysis using finite element method was
employed for modal, impulse loading and frequency response
analyses of the slab under the aforementioned loading condition.
Results from the static and dynamic analyses, comprising of the slab
fundamental frequencies and mode shapes, dynamic amplification
factor, maximum deflection, stress distributions among other
valuable outcomes are presented and discussed. These were gauged
with the limiting provisions in the design code with a view of
justifying valid optimization objective function for the structure that
can ensure both adequate strength and economical section for large
clear span slabs. This is necessary owing to the continued increase in
cost of erecting building structures and the squeeze on public finance
globally.
Abstract: Hypertension is a common condition causing cardio
and cerebrovascular complications. Portugal has one of the highest
mortality rates from stroke and a high prevalence of hypertension.
Systolic Blood Pressure (SBP) is an important risk factor for
cardiovascular events (myocardial infarction and stroke) and
premature mortality, particularly in the elderly population. The
present study aims to estimate the prevalence of hypertension in a
Portuguese population living in a coastal city and to identify some of
its determinants (namely gender, age, the body mass index and
physical activity frequency). A total of 91 adults who attended three pharmacies of a coastal
city in the center of Portugal, between May and August of 2013 were
evaluated. Attendants who reported to have diabetes or taking
antihypertensive drugs in the 2 previous weeks were excluded from
the study. Sociodemographic factors, BMI, habits of exercise and BP
were assessed. Hypertension was defined as blood pressure ≥140/90
mmHg. The majority of the studied population was constituted by women
(75.8%), with a mean age of 54.2±1.6 years old, married or living in
civil union and that had completed secondary school or had higher
education (40%). They presented a mean BMI of 26.2±4.76 Kg/m2.,
and were sedentary. The mean BP was 127.0±17.77mmHg- 74.69 ±
9.53. In this population we found 4.3% of people with hypertension
and 16.1% with normal high blood pressure. Men exhibit a tendency to present higher systolic blood pressure
values than women. Of all the factors considered, SBP values also
tended to be higher with age and higher BMI values.
Despite the fact that the mean values of SBP did not present values
higher than 140 mmHg we must be concerned because the studied
population is undiagnosed for hypertension. Although this is a preliminary study, it might be a prelude to the
upcoming research about the underlying factors responsible for the
occurrence of SBP.