Abstract: For evaluating the severity of Chronic Obstructive Pulmonary Disease (COPD), one is interested in inspecting the airway wall thickening due to inflammation. Although airway segmentations have being well developed to reconstruct in high order, airway wall segmentation remains a challenge task. While tackling such problem as a multi-surface segmentation, the interrelation within surfaces needs to be considered. We propose a new method for three-dimensional airway wall segmentation using spring structural active contour model. The method incorporates the gravitational field of the image and repelling force field of the inner lumen as the soft constraint and the geometric spring structure of active contour as the hard constraint to approximate a three-dimensional coupled surface readily for thickness measurements. The results show the preservation of topology constraints of coupled surfaces. In conclusion, our springy, soft-tissue-like structure ensures the globally optimal solution and waives the shortness following by the inevitable improper inner surface constraint.
Abstract: The aim of this paper is to understand how peers can
influence adolescent girls- dieting behaviour and their body image.
Departing from imitation and social learning theories, we study
whether adolescent girls tend to model their peer group dieting
behaviours, thus influencing their body image construction. Our
study was conducted through an enquiry applied to a cluster sample
of 466 adolescent high school girls in Lisbon city public schools. Our
main findings point to an association between girls- and peers-
dieting behaviours, thus reinforcing the modelling hypothesis.
Abstract: Temperature is one of the most principle factors affects aquaculture system. It can cause stress and mortality or superior environment for growth and reproduction. This paper presents the control of pond water temperature using artificial intelligence technique. The water temperature is very important parameter for shrimp growth. The required temperature for optimal growth is 34oC, if temperature increase up to 38oC it cause death of the shrimp, so it is important to control water temperature. Solar thermal water heating system is designed to supply an aquaculture pond with the required hot water in Mersa Matruh in Egypt. Neural networks are massively parallel processors that have the ability to learn patterns through a training experience. Because of this feature, they are often well suited for modeling complex and non-linear processes such as those commonly found in the heating system. Artificial neural network is proposed to control water temperature due to Artificial intelligence (AI) techniques are becoming useful as alternate approaches to conventional techniques. They have been used to solve complicated practical problems. Moreover this paper introduces a complete mathematical modeling and MATLAB SIMULINK model for the aquaculture system. The simulation results indicate that, the control unit success in keeping water temperature constant at the desired temperature by controlling the hot water flow rate.
Abstract: In the current work, a numerical parametric study was
performed in order to model the fluid mechanics in the riser of a
bubbling fluidized bed (BFB). The gas-solid flow was simulated by
mean of a multi-fluid Eulerian model incorporating the kinetic theory
for solid particles. The bubbling fluidized bed was simulated two
dimensionally by mean of a Computational Fluid Dynamic (CFD)
commercial software package, Fluent. The effects of using different
inter-phase drag function (the drag model of Gidaspow, Syamlal and
O-Brien and the EMMS drag model) on the model predictions were
evaluated and compared. The results showed that the drag models of
Gidaspow and Syamlal and O-Brien overestimated the drag force for
the FCC particles and predicted a greater bed expansion in
comparison to the EMMS drag model.
Abstract: Surface currents play a major role in the distribution
of contaminants, the connectivity of marine populations, and can
influence the vertical and horizontal distribution of nutrients within
the water column. This paper aims to determine the effects of sea
breeze-wind patterns on the climatology of the surface currents on the
continental shelf surrounding Rottnest Island, WA Australia. The
alternating wind patterns allow for full cyclic rotations of wind
direction, permitting the interpretation of the effect of the wind on the
surface currents. It was found that the surface currents only clearly
follow the northbound Capes Current in times when the Fremantle
Doctor sets in. Surface currents react within an hour to a change of
direction of the wind, allowing southerly currents to dominate during
strong northerly sea breezes, often followed by mixed currents
dominated by eddies in the inter-lying times.
Abstract: The chemistry of sulphone hydrazide has gained increase interest in both synthetic organic chemistry and biological fields and has considerable value. The therapeutic importance of these compounds is the attractive force to continue research in such a point. The present review covers the literature up to date for the synthesis, reactions and applications of such compounds.
Abstract: Medical applications are among the most impactful
areas of microrobotics. The ultimate goal of medical microrobots is
to reach currently inaccessible areas of the human body and carry out
a host of complex operations such as minimally invasive surgery
(MIS), highly localized drug delivery, and screening for diseases at
their very early stages. Miniature, safe and efficient propulsion
systems hold the key to maturing this technology but they pose
significant challenges. A new type of propulsion developed recently,
uses multi-flagella architecture inspired by the motility mechanism of
prokaryotic microorganisms. There is a lack of efficient methods for
designing this type of propulsion system. The goal of this paper is to
overcome the lack and this way, a numerical strategy is proposed to
design multi-flagella propulsion systems. The strategy is based on the
implementation of the regularized stokeslet and rotlet theory, RFT
theory and new approach of “local corrected velocity". The effects of
shape parameters and angular velocities of each flagellum on overall
flow field and on the robot net forces and moments are considered.
Then a multi-layer perceptron artificial neural network is designed
and employed to adjust the angular velocities of the motors for
propulsion control. The proposed method applied successfully on a
sample configuration and useful demonstrative results is obtained.
Abstract: Cylindrical concrete reservoirs are appropriate choice
for storing liquids as water, oil and etc. By using of the pre-cast
concrete reservoirs instead of the in-situ constructed reservoirs, the
speed and precision of the construction would considerably increase.
In this construction method, wall and roof panels would make in
factory with high quality materials and precise controlling. Then,
pre-cast wall and roof panels would carry out to the construction site
for assembling. This method has a few faults such as: the existing
weeks in connection of wall panels together and wall panels to
foundation. Therefore, these have to be resisted under applied loads
such as seismic load. One of the innovative methods which was
successfully applied for seismic retrofitting of numerous pre-cast
cylindrical water reservoirs in New Zealand, using of the high tensile
cables around the reservoirs and post-tensioning them. In this paper,
analytical modeling of wall and roof panels and post-tensioned
cables are carried out with finite element method and the effect of
height to diameter ratio, post-tensioning force value, liquid level in
reservoir, installing position of tendons on seismic response of
reservoirs are investigated.
Abstract: The performances of small and medium enterprises
have stagnated in the last two decades. This has mainly been due to
the emergence of HIV / Aids. The disease has had a detrimental
effect on the general economy of the country leading to morbidity
and mortality of the Kenyan workforce in their primary age. The
present study sought to establish the economic impact of HIV / Aids
on the micro-enterprise development in Obunga slum – Kisumu, in
terms of production loss, increasing labor related cost and to establish
possible strategies to address the impact of HIV / Aids on microenterprises.
The study was necessitated by the observation that most
micro-enterprises in the slum are facing severe economic and social
crisis due to the impact of HIV / Aids, they get depleted and close
down within a short time due to death of skilled and experience
workforce. The study was carried out between June 2008 and June
2009 in Obunga slum. Data was subjected to computer aided
statistical analysis that included descriptive statistic, chi-squared and
ANOVA techniques. Chi-squared analysis on the micro-enterprise
owners opinion on the impact of HIV / Aids on depletion of microenterprise
compared to other diseases indicated high levels of the
negative effects of the disease at significance levels of P
Abstract: Axisymmetric vibration of an infinite Pyrocomposite
circular hollow cylinder made of inner and outer pyroelectric layer of
6mm-class bonded together by a Linear Elastic Material with Voids
(LEMV) layer is studied. The exact frequency equation is obtained
for the traction free surfaces with continuity condition at the
interfaces. Numerical results in the form of data and dispersion
curves for the first and second mode of the axisymmetric vibration of
the cylinder BaTio3 / Adhesive / BaTio3 by taking the Adhesive layer
as an existing Carbon Fibre Reinforced Polymer (CFRP) are
compared with a hypothetical LEMV layer with and without voids
and as well with a pyroelectric hollow cylinder. The damping is
analyzed through the imaginary parts of the complex frequencies.
Abstract: Ambiguities in effects of earthquake on various
structures in all earthquake codes would necessitate more study and
research concerning influential factors on dynamic behavior.
Previous studies which were done on different features in different
buildings play a major role in the type of response a structure makes
to lateral vibrations. Diagnosing each of these irregularities can help
structure designers in choosing appropriate setbacks for decreasing
possible damages. Therefore vertical setback is one of the irregularity
factors in the height of the building where can be seen in skyscrapers
and hotels. Previous researches reveal notable changes in the place of
these setbacks showing dynamic response of the structure.
Consequently analyzing 48 models of concrete frames for 3, 6 and 9
stories heights with three different bays in general shape of a surface
decline by height have been constructed in ETABS2000 software,
and then the shape effect of each and every one of these frames in
period scale has been discussed. The result of this study reveals that
not only mass, stiffness and height but also shape of the frame is
influential.
Abstract: During the last few years, several sheet hydroforming
processes have been introduced. Despite the advantages of these
methods, they have some limitations. Of the processes, the two main
ones are the standard hydroforming and hydromechanical deep
drawing. A new sheet hydroforming die set was proposed that has the
advantages of both processes and eliminates their limitations. In this
method, a polyurethane plate was used as a part of the die-set to
control the blank holder force. This paper outlines the Taguchi
optimization methodology, which is applied to optimize the effective
parameters in forming cylindrical cups by the new die set of sheet
hydroforming process. The process parameters evaluated in this
research are polyurethane hardness, polyurethane thickness, forming
pressure path and polyurethane hole diameter. The design of
experiments based upon L9 orthogonal arrays by Taguchi was used
and analysis of variance (ANOVA) was employed to analyze the
effect of these parameters on the forming pressure. The analysis of
the results showed that the optimal combination for low forming
pressure is harder polyurethane, bigger diameter of polyurethane hole
and thinner polyurethane. Finally, the confirmation test was derived
based on the optimal combination of parameters and it was shown
that the Taguchi method is suitable to examine the optimization
process.
Abstract: Based on the field investigation and long term remote
sensing data, the dynamics of the alpine wetland in the river basin and
their response to climate change were studied. Results showed the
alpine wetlands accounted for 3.73% of total basin in 2010. Lake and
river appeared an increasing trend in the past 30 years, with an
increase of 34.36 % and 24.57%. However, swamp exhibited a
tendency of decreasing with 233.74 km2. Annual average temperature,
maximum temperature, minimum temperature and precipitation in the
river basin all exhibited an increasing trend, whereas relative humidity
exhibited a decreasing trend. Ice and snow melting are main reasons of
lake and river area enhancement and swamp area descend. There
existed 91.78%-97.86% of reduced swamp converted into lakes on the
basis of remote sensing image interpretation. China-s government
policy of implementing development in the river basin is the major
driving force of artificial wetland growth.
Abstract: Hydrogen sulfide (H2S) is a very toxic gas that is produced in very large quantities in the oil and gas industry. It cannot be flared to the atmosphere and Claus process based gas plants are used to recover the sulfur and convert the hydrogen to water. In this paper, we present optical characterization of an atmospheric pressure microwave plasma torch for H2S dissociation into hydrogen and sulfur. The torch is operated at 2.45 GHz with power up to 2 kW. Three different gases can simultaneously be injected in the plasma torch. Visual imaging and optical emission spectroscopy are used to characterize the plasma for varying gas flow rates and microwave power. The plasma length, emission spectra and temperature are presented. The obtained experimental results validate our earlier published simulation results of plasma torch.
Abstract: Horizontal wells are proven to be better producers
because they can be extended for a long distance in the pay zone.
Engineers have the technical means to forecast the well productivity
for a given horizontal length. However, experiences have shown that
the actual production rate is often significantly less than that of
forecasted. It is a difficult task, if not impossible to identify the real
reason why a horizontal well is not producing what was forecasted.
Often the source of problem lies in the drilling of horizontal section
such as permeability reduction in the pay zone due to mud invasion
or snaky well patterns created during drilling. Although drillers aim
to drill a constant inclination hole in the pay zone, the more frequent
outcome is a sinusoidal wellbore trajectory. The two factors, which
play an important role in wellbore tortuosity, are the inclination and
side force at bit. A constant inclination horizontal well can only be
drilled if the bit face is maintained perpendicular to longitudinal axis
of bottom hole assembly (BHA) while keeping the side force nil at
the bit. This approach assumes that there exists no formation force at
bit. Hence, an appropriate BHA can be designed if bit side force and
bit tilt are determined accurately. The Artificial Neural Network
(ANN) is superior to existing analytical techniques. In this study, the
neural networks have been employed as a general approximation tool
for estimation of the bit side forces. A number of samples are
analyzed with ANN for parameters of bit side force and the results
are compared with exact analysis. Back Propagation Neural network
(BPN) is used to approximation of bit side forces. Resultant low
relative error value of the test indicates the usability of the BPN in
this area.
Abstract: For best collaboration, Asynchronous tools and particularly the discussion forums are the most used thanks to their flexibility in terms of time. To convey only the messages that belong to a theme of interest of the tutor in order to help him during his tutoring work, use of a tool for classification of these messages is indispensable. For this we have proposed a semantics classification tool of messages of a discussion forum that is based on LSA (Latent Semantic Analysis), which includes a thesaurus to organize the vocabulary. Benefits offered by formal ontology can overcome the insufficiencies that a thesaurus generates during its use and encourage us then to use it in our semantic classifier. In this work we propose the use of some functionalities that a OWL ontology proposes. We then explain how functionalities like “ObjectProperty", "SubClassOf" and “Datatype" property make our classification more intelligent by way of integrating new terms. New terms found are generated based on the first terms introduced by tutor and semantic relations described by OWL formalism.
Abstract: This paper presents the design, development and characterization of contractile water jet thruster (CWJT) for mini underwater robot. Instead of electric motor, this CWJT utilizes the Ionic Polymer Metal Composite (IPMC) as the actuator to generate the water jet. The main focus of this paper is to analyze the conceptual design of the proposed CWJT which would determine the thrust force value, jet flow behavior and actuator’s stress. Those thrust force and jet flow studies were carried out using Matlab/Simscape simulation software. The actuator stress had been analyzed using COSMOS simulation software. The results showed that there was no significant change for jet velocity at variable cross sectional nozzle area. However, a significant change was detected for jet velocity at different nozzle cross sectional area ratio which was up to 37%. The generated thrust force has proportional relation to the nozzle cross sectional area.
Abstract: The spreading characteristics of acoustically excited
swirling double-concentric jets were studied experimentally. The
central jet was acoustically excited at low and high pulsation
intensities. A smoke wire flow visualization and a hot-wire
anemometer velocity measurement results show that excitation forces
a vortex ring to roll-up from the edge of the central tube during each
excitation period. At low pulsation intensities, the vortex ring evolves
downstream, and eventually breaks up into turbulent eddies. At high
pulsation intensities, the primary vortex ring evolves and a series of
trailing vortex rings form during the same period of excitation. The
trailing vortex rings accelerate while evolving downstream and
overtake the primary vortex ring within the same cycle. In the
process, the primary vortex ring becomes unstable and breaks up
early. The effect of the fast traveling trailing vortex rings combined
with the swirl motion of the annular flow improve jet spreading
compared with the naturally evolving jets.
Abstract: A bird strike can cause damage to stationary and
rotating aircraft engine parts, especially the engine fan. This paper
presents a bird strike simulated by blocking four stator blade
passages. It includes the numerical results of the unsteady lowfrequency
aerodynamic forces and the aeroelastic behaviour caused
by a non-symmetric upstream flow affecting the first two rotor blade
stages in the axial-compressor of a jet engine. The obtained results
show that disturbances in the engine inlet strongly influence the level
of unsteady forces acting on the rotor blades. With a partially
blocked inlet the whole spectrum of low-frequency harmonics is
observed. Such harmonics can lead to rotor blade damage. The lowfrequency
amplitudes are higher in the first stage rotor blades than in
the second stage. In both rotor blades stages flutter appeared as a
result of bird strike.
Abstract: Many studies have applied the Theory of Planned
Behavior (TPB) in predicting health behaviors among unique
populations. However, a new paradigm is emerging where focus is
now directed to modification and expansion of the TPB model rather
than utilization of the traditional theory. This review proposes new
models modified from the Theory of Planned Behavior and suggest
an appropriate study design that can be used to test the models within
physical activity and dietary practice domains among Type 2
diabetics in Kenya. The review was conducted by means of literature
search in the field of nutrition behavior, health psychology and
mixed methods using predetermined key words. The results identify
pre-intention and post intention gaps within the TPB model that need
to be filled. Additional psychosocial factors are proposed to be
included in the TPB model to generate new models and the efficacy
of these models tested using mixed methods design.