Abstract: To understand the friction stir welding process, it is
very important to know the nature of the material flow in and around
the tool. The process is a combination of both thermal as well as
mechanical work i.e. it is a coupled thermo-mechanical process.
Numerical simulations are very much essential in order to obtain a
complete knowledge of the process as well as the physics underlying
it. In the present work a model based approach is adopted in order to
study material flow. A thermo-mechanical based CFD model is
developed using a Finite Element package, Comsol Multiphysics.
The fluid flow analysis is done. The model simultaneously predicts
shear strain fields, shear strain rates and shear stress over the entire
workpiece for the given conditions. The flow fields generated by the
streamline plot give an idea of the material flow. The variation of
dynamic viscosity, velocity field and shear strain fields with various
welding parameters is studied. Finally the result obtained from the
above mentioned conditions is discussed elaborately and concluded.
Abstract: We propose new multiple-channel piezoelectric (PZT)
actuated tunable optical filter based on racetrack multi-ring
resonators for wavelength de-multiplexing network applications. We
design tunable eight-channel wavelength de-multiplexer consisting of
eight cascaded PZT actuated tunable multi-ring resonator filter with a
channel spacing of 1.6nm. The filter for each channel is basically
structured on a suspended beam, sandwiched with piezoelectric
material and built in integrated ring resonators which are placed on
the middle of the beam to gain uniform stress and linearly varying
longitudinal strain. A reference single mode serially coupled multi
stage racetrack ring resonator with the same radii and coupling length
is designed with a line width of 0.8974nm with a flat top pass band at
1dB of 0.5205nm and free spectral range of about 14.9nm. In each
channel, a small change in the perimeter of the rings is introduced to
establish the shift in resonance wavelength as per the defined channel
spacing. As a result, when a DC voltage is applied, the beams will
elongate, which involves mechanical deformation of the ring
resonators that induces a stress and a strain, which brings a change in
refractive index and perimeter of the rings leading to change in the
output spectrum shift providing the tunability of central wavelength
in each channel. Simultaneous wave length shift as high as
45.54pm/
Abstract: The iron environment in Fe-doped Vycor Anode was
investigated with EXAFS using Brookhaven Synchrotron Light
Source. The iron-reducing Shewanella oneidensis culture was grown
in a microbial fuel cell under anaerobic respiration. The Fe bond
length was found to decrease and correlate with the amount of
biofilm growth on the Fe-doped Vycor Anode. The data suggests that
Fe-doped Vycor Anode would be a good substrate to study the
Shewanella oneidensis nanowire structure using EXAFS.
Abstract: The arsenic and iron environments in different growth
stages have been studied with EXAFS and XANES using
Brookhaven Synchrotron Light Source. Collard Greens plants were
grown and tissue samples were harvested. The project studied the
EXAFS and XANES of tissue samples using As and Fe K-edges. The
Fe absorption and the Fourier transform bond length information
were used as a control comparison. The Fourier transform of the
XAFS data revealed the coexistence of As (III) and As (V) in the As
bonding environment inside the studied plant tissue samples,
although the soil only had As (III). The data suggests that Collard
Greens has a novel pathway to handle arsenic absorption in soil.
Abstract: Press-hardened profiles are used e.g. for automotive
applications in order to improve light weight construction due to the
high reachable strength. The application of interior water-air spray
cooling contributes to significantly reducing the cycle time in the
production of heat-treated tubes. This paper describes a new
manufacturing method for producing press-hardened hollow profiles
by means of an additional interior cooling based on a water-air spray.
Furthermore, this paper provides the results of thorough
investigations on the properties of press-hardened tubes in
dependence of varying spray parameters.
Abstract: This paper presents the development of a robot car
that can track the motion of an object by detecting its color through
an Android device. The employed computer vision algorithm uses the
OpenCV library, which is embedded into an Android application of a
smartphone, for manipulating the captured image of the object. The
captured image of the object is subjected to color conversion and is
transformed to a binary image for further processing after color
filtering. The desired object is clearly determined after removing
pixel noise by applying image morphology operations and contour
definition. Finally, the area and the center of the object are
determined so that object’s motion to be tracked. The smartphone
application has been placed on a robot car and transmits by Bluetooth
to an Arduino assembly the motion directives so that to follow
objects of a specified color. The experimental evaluation of the
proposed algorithm shows reliable color detection and smooth
tracking characteristics.
Abstract: The effect of additional magnesium oxide (MgO) was
investigated by using the tungsten oxide supported on silica catalyst
(WOx/SiO2) physically mixed with MgO in a weight ratio 1:1. The
both fresh and spent catalysts were characterized by FT-Raman
spectrometer, UV-Vis spectrometer, X-Ray diffraction (XRD) and
temperature programmed oxidation (TPO). The results indicated that
the additional MgO could enhance the conversion of trans-2-butene
due to isomerization reaction. However, adding MgO would increase
the amount of coke deposit on the WOx/SiO2 catalyst. The TPO
profile presented two peaks when the WOx/SiO2 catalyst was
physically mixed with MgO. The further peak was suggested that
came from coke precursor could be produced by isomerization
reaction of undesired product. Then, the occurred coke precursor
could deposit and form coke on the acid catalyst.
Abstract: This paper investigates the benefits of deliberately
unbalancing both operation time means (MTs) and unreliability
(failure and repair rates) for non-automated production lines. The
lines were simulated with various line lengths, buffer capacities,
degrees of imbalance and patterns of MT and unreliability imbalance.
Data on two performance measures, namely throughput (TR) and
average buffer level (ABL) were gathered, analyzed and compared to
a balanced line counterpart. A number of conclusions were made
with respect to the ranking of configurations, as well as to the
relationships among the independent design parameters and the
dependent variables. It was found that the best configurations are a
balanced line arrangement and a monotone decreasing MT order,
coupled with either a decreasing or a bowl unreliability configuration,
with the first generally resulting in a reduced TR and the second
leading to a lower ABL than those of a balanced line.
Abstract: Due to rapid pressured of population growth, city has
started to lose its old tradition. City becomes congested with
uncomfortably living. Urban renewal refers orderly development of
settlements as well as land redevelopment. For this paper Chittagong
city has been selected as study area. It had a great tradition but it has
been losing its concord. Land use pattern of this place is also
haphazard due to lack of planning intervention. Renewal plan is
needed to ascertain suitable redevelopment and to recommend on
preservation of city heritage structure. The goal of this study is to
prepare a renewal plan using local planning approach. Social impact
methods have been used to achieve this goal. Both primary and
secondary data are used to achieve the goal. This study may find out
a complete solution for healthy living in old Part of city. This study
will help to preserve its tradition and makes urban lives more livable.
Abstract: Moringa oleifera is a nutritious vegetable tree with
varieties of potential uses, as almost every part of the Moringa
oleifera tree can be used for food. This study was conducted in Oyo
State, Nigeria, to find out the level of acceptability of Moringa
oleifera diversified products among rural and urban dwellers.
Purposive sampling was used to select two local governments’ areas.
Stratified sampling technique was also used to select one community
each from rural and urban areas while snowball sampling technique
was used to select ten respondents each from the two communities,
making a total number of forty respondents. Data were analyzed
using frequencies, percentages, Chi-square, Pearson Product Moment
Correlation and regression analysis. Result from the study revealed
that majority of the respondents (80%) fell within the age range of
20-49 years and 55% of them were male, 55% were married, 70% of
them were Christians, 80% of them had tertiary education. The result
also showed that 85% were aware of the Moringa plant and (65%) of
them have consumed Moringa oleifera and the perception statements
on the benefits of Moringa oleifera indicated that (52.5%) of the
respondents rated Moringa oleifera to be favorable, most of them had
high acceptability for Moringa egusi soup, Moringa tea, Moringa pap
and yam pottage with Moringa. The result of the hypotheses testing
showed that there is a significant relationship between sex of the
respondents and acceptability of the diversified Moringa oleifera
products (x2=6.465, p = 0.011). There is also a significant
relationship between family size of the respondents level of
acceptability of the Moringa oleifera products (r = 0.327, p = 0.040).
Based on the level of acceptability of Moringa oleifera diversified
products; the plant is of great economic importance to the populace.
Therefore, there should be more public awareness through the media
to enlighten people on the beneficial effects of Moringa oleifera.
Abstract: Rainfall runoff models play important role in
hydrological predictions. However, the model is only one part of the
process for creation of flood prediction. The aim of this paper is to
show the process of successful prediction for flood event (May 15 –
May 18 2014). Prediction was performed by rainfall runoff model
HEC–HMS, one of the models computed within Floreon+ system.
The paper briefly evaluates the results of automatic hydrologic
prediction on the river Olše catchment and its gages Český Těšín and
Věřňovice.
Abstract: In this study, ultrasonic assisted machining (UAM) technique is applied in side-surface milling experiment for glass-ceramic workpiece material. The tungsten carbide cutting-tool with diamond coating is used in conjunction with two kinds of cooling/lubrication mediums such as water-soluble (WS) cutting fluid and minimum quantity lubricant (MQL). Full factorial process parameter combinations on the milling experiments are planned to investigate the effect of process parameters on cutting performance. From the experimental results, it tries to search for the better process parameter combination which the edge-indentation and the surface roughness are acceptable. In the machining experiments, ultrasonic oscillator was used to excite a cutting-tool along the radial direction producing a very small amplitude of vibration frequency of 20KHz to assist the machining process. After processing, toolmaker microscope was used to detect the side-surface morphology, edge-indentation and cutting tool wear under different combination of cutting parameters, and analysis and discussion were also conducted for experimental results. The results show that the main leading parameters to edge-indentation of glass ceramic are cutting depth and feed rate. In order to reduce edge-indentation, it needs to use lower cutting depth and feed rate. Water-soluble cutting fluid provides a better cooling effect in the primary cutting area; it may effectively reduce the edge-indentation and improve the surface morphology of the glass ceramic. The use of ultrasonic assisted technique can effectively enhance the surface finish cleanness and reduce cutting tool wear and edge-indentation.
Abstract: In this paper static scheme of under-frequency based load shedding is considered for chemical and petrochemical industries with islanded distribution networks relying heavily on the primary commodity to ensure minimum production loss, plant downtime or critical equipment shutdown. A simplistic methodology is proposed for in-house implementation of this scheme using underfrequency relays and a step by step guide is provided including the techniques to calculate maximum percentage overloads, frequency decay rates, time based frequency response and frequency based time response of the system. Case study of FFL electrical system is utilized, presenting the actual system parameters and employed load shedding settings following the similar series of steps. The arbitrary settings are then verified for worst overload conditions (loss of a generation source in this case) and comprehensive system response is then investigated.
Abstract: This paper presents the design and fabrication of an
optical window for an optical modulator toward image sensing
applications. An optical window consists of micrometer-order SiO2
capillaries (porous solid) that can modulate transmission light
intensity by moving the liquid in and out of porous solid. A high
optical transmittance of the optical window can be achieved due to
refractive index matching when the liquid is penetrated into the
porous solid. Otherwise, its light transmittance is lower because of
light reflection and scattering by air holes and capillary walls. Silicon
capillaries fabricated by deep reactive ion etching (DRIE) process are
completely oxidized to form the SiO2 capillaries. Therefore, high
aspect ratio SiO2 capillaries can be achieved based on silicon
capillaries formed by DRIE technique. Large compressive stress of
the oxide causes bending of the capillary structure, which is reduced
by optimizing the design of device structure. The large stress of the
optical window can be released via thin supporting beams. A 7.2 mm
x 9.6 mm optical window area toward a fully integrated with the
image sensor format is successfully fabricated and its optical
transmittance is evaluated with and without inserting liquids (ethanol
and matching oil). The achieved modulation range is approximately
20% to 35% with and without liquid penetration in visible region
(wavelength range from 450 nm to 650 nm).
Abstract: Optical radiation emitted from a metal-coated fiber tip apex at liquid-air interface was measured. The intensity of the output radiation was strongly depend on the relative position of the tip to a liquid-air interface and varied with surface fluctuations. This phenomenon permits in-situ real-time investigation of nano-metric vibrations of the liquid surface and provides a basis for development of various origin ultrasensitive vibration detecting sensors. The described method can be used for detection of week seismic vibrations.
Abstract: Taiwan is a hyper endemic area for the Hepatitis B
virus (HBV). The estimated total number of HBsAg carriers in the
general population who are more than 20 years old is more than 3
million. Therefore, a case record review is conducted from January
2003 to June 2007 for all patients with a diagnosis of acute hepatitis
who were admitted to the Emergency Department (ED) of a
well-known teaching hospital. The cost for the use of medical
resources is defined as the total medical fee. In this study, principal
component analysis (PCA) is firstly employed to reduce the number of
dimensions. Support vector regression (SVR) and artificial neural
network (ANN) are then used to develop the forecasting model. A total
of 117 patients meet the inclusion criteria. 61% patients involved in
this study are hepatitis B related. The computational result shows that
the proposed PCA-SVR model has superior performance than other
compared algorithms. In conclusion, the Child-Pugh score and
echogram can both be used to predict the cost of medical resources for
patients with acute hepatitis in the ED.
Abstract: In this paper, the effects of fiber types and elevated
temperatures on compressive strength, modulus of rapture and the
bond characteristics of fiber reinforced concretes (FRC) are
presented. By using the three different types of fibers (steel fiber-SF,
polypropylene-PPF and polyvinyl alcohol-PVA), FRC specimens
were produced and exposed to elevated temperatures up to 800 ºC for
1.5 hours. In addition, a plain concrete (without fiber) was produced
and used as a control. Test results obtained showed that the steel fiber
reinforced concrete (SFRC) had the highest compressive strength,
modulus of rapture and bond stress values at room temperatures, the
residual bond, flexural and compressive strengths of both FRC and
plain concrete dropped sharply after exposure to high temperatures.
The results also indicated that the reduction of bond, flexural and
compressive strengths with increasing the exposed temperature was
relatively less for SFRC than for plain, and FRC with PPF and PVA.
Abstract: In this study, polycaprolactone (PCL) was dissolved
in chloroform:ethanol solvent system at a concentration of 18 w/v %.
1, 2, 4, and 6 droplets of formic acid were added to the prepared 10ml
PCL-chloroform:ethanol solutions separately. Fibrous webs were
produced by electrospinning technique based on the horizontal
working principle. Morphology of the webs was investigated by
using scanning electron microscopy (SEM) whereas fiber diameters
were measured by Image J Software System. The effect of formic
acid addition to the mostly used chloroform solvent on fiber
morphology was examined.
Results indicate that there is a distinct fall in fiber diameter with
the addition of formic acid drops. The average fiber diameter was
measured as 2.22μm in PCL /chloroform:ethanol solution system. On
the other hand, 328nm and 256 nm average fiber diameters were
measured for the samples of 4 drops and 6 drops formic acid added.
This study offers alternative solvent systems to produce nanoscaled,
nontoxic PCL fibrous webs by electrospinning technique.
Abstract: Fixed-geometry hydrodynamic journal bearings are
one of the best supporting systems for several applications of rotating
machinery. Cylindrical journal bearings present excellent loadcarrying
capacity and low manufacturing costs, but they are subjected
to the oil-film instability at high speeds. An attempt of overcoming
this instability problem has been the development of non-circular
journal bearings. This work deals with an analysis of oil-lubricated
elliptical journal bearings using the finite element method. Steadystate
and dynamic performance characteristics of elliptical bearings
are rendered by zeroth- and first-order lubrication equations obtained
through a linearized perturbation method applied on the classical
Reynolds equation. Four-node isoparametric rectangular finite
elements are employed to model the bearing thin film flow. Curves of
elliptical bearing load capacity and dynamic force coefficients are
rendered at several operating conditions. The results presented in this
work demonstrate the influence of the bearing ellipticity on its
performance at different loading conditions.
Abstract: Essential oils have a significant antimicrobial activity.
These oils can successfully replace the antibiotics. So, the
microorganisms show their inefficiencies resistant for the antibiotics.
For this reason, we study the physicochemical analysis and
antimicrobial activity of the essential oil of Daucus carota. The
extraction is done by steam distillation of water which brought us a
very significant return of 4.65%. The analysis of the essential oil is
performed by GC / MS and has allowed us to identify 32 compounds
in the oil of D. carota flowering tops of Bouira. Three of which are in
the majority are the α-Pinene (22.3%), the carotol (21.7%) and the
limonene (15.8%).