Abstract: The temperature dependence of wettability (wetting
angle, Θ (T)) for Ag-based melts on graphite and Al2O3 substrates is
compared. Typical alloying effects are found, as the Ag host metal is
gradually replaced by various metallic elements. The essence of
alloying lies in the change of the electron/atom (e/a) ratio. This ratio
is also manifested in the shift of wetting angles on the same substrate.
Nevertheless, the effects are partially smeared by other
(metallurgical) factors, like the interaction between the oxygenalloying
elements and by the graphite substrate-oxygen interaction. In
contrast, such effects are not pronounced in the case of Al2O3
substrates. As a consequence, Θ(T) exhibits an opposite trend in the
case of two substrates. Crossovers of the Θ(T) curves were often
found. The positions of crossovers depend on the chemical character
and concentration of solute atoms. Segregation and epitaxial texture
formation after solidification were also observed in certain alloy
drops, especially in high concentration range. This phenomenon is
not yet explained in every detail.
Abstract: The use OF adhesive anchors for wooden constructions is an efficient technology to connect and design timber members in new timber structures and to rehabilitate the damaged structural members of historical buildings. Due to the lack of standard regulation in this specific area of structural design, designers’ choices are still supported by test analysis that enables knowledge, and the prediction, of the structural behaviour of glued in rod joints. The paper outlines an experimental research activity aimed at identifying the tensile resistance capacity of several new adhesive joint prototypes made of epoxy resin, steel bar and timber, Oak and Douglas Fir species. The development of new adhesive connectors has been carried out by using epoxy to glue stainless steel bars into pre-drilled holes, characterised by smooth and rough internal surfaces, in timber samples. The realization of a threaded contact surface using a specific drill bit has led to an improved bond between wood and epoxy. The applied changes have also reduced the cost of the joints’ production. The paper presents the results of this parametric analysis and a Finite Element analysis that enables identification and study of the internal stress distribution in the proposed adhesive anchors.
Abstract: In this paper, two options of anodic alumina barrier
layer thinning have been demonstrated. The approaches varied with
the duration of the voltage step. It was found that too long step of the
barrier layer thinning process leads to chemical etching of the
nanopores on their top. At the bottoms pores are not fully opened
what is disadvantageous for further applications in nanofabrication.
On the other hand, while the duration of the voltage step is controlled
by the current density (value of the current density cannot exceed
75% of the value recorded during previous voltage step) the pores are
fully opened. However, pores at the bottom obtained with this
procedure have smaller diameter, nevertheless this procedure
provides electric contact between the bare aluminum (substrate) and
electrolyte, what is suitable for template assisted electrodeposition,
one of the most cost-efficient synthesis method in nanotechnology.
Abstract: A novel hybrid model of the lumbar spine, allowing
fast static and dynamic simulations of the disc pressure
and the spine mobility, is introduced in this work. Our
contribution is to combine rigid bodies, deformable finite
elements, articular constraints, and springs into a unique model
of the spine. Each vertebra is represented by a rigid body
controlling a surface mesh to model contacts on the facet
joints and the spinous process. The discs are modeled using
a heterogeneous tetrahedral finite element model. The facet
joints are represented as elastic joints with six degrees of
freedom, while the ligaments are modeled using non-linear
one-dimensional elastic elements. The challenge we tackle
is to make these different models efficiently interact while
respecting the principles of Anatomy and Mechanics.
The mobility, the intradiscal pressure, the facet joint force and
the instantaneous center of rotation of the lumbar spine are
validated against the experimental and theoretical results of
the literature on flexion, extension, lateral bending as well as
axial rotation.
Our hybrid model greatly simplifies the modeling task and
dramatically accelerates the simulation of pressure within the
discs, as well as the evaluation of the range of motion and the
instantaneous centers of rotation, without penalizing precision.
These results suggest that for some types of biomechanical
simulations, simplified models allow far easier modeling and
faster simulations compared to usual full-FEM approaches
without any loss of accuracy.
Abstract: The present work aims to throw light on the effects of
arcing in air on the surface state of contact pastilles made of silvernickel
Ag-Ni (60/40). Also, the photoelectric emission from these
electrical contacts has been investigated in the spectral range of 196-
256 nm. In order to study the effects of arcing on the EWF, the
metallic samples were subjected to electrical arcs in air, at
atmospheric pressure and room temperature, after that, they have
been introduced into the vacuum chamber of an experimental UHV
set-up for EWF measurements. Both Fowler method of isothermal
curves and linearized Fowler plots were used for the measurement of
the EWF by the photoelectric effect.
It has been found that the EWF varies with the number of applied
arcs. Thus, after 500 arcs in air, the observed EWF increasing is
probably due to progressive inclusion of oxide on alloy surface.
Microscopic examination is necessary to get better understandings on
EWF of silver alloys, for both virgin and arced electrical contacts.
Abstract: The adsorption efficiency of fired clayey pellets of 5
and 8 mm diameter size for Cu(II) and Zn(II) ion removal from a
waste printing developer was studied. In order to investigate the
influence of contact time, adsorbent mass and pellet size on the
adsorption efficiency the batch mode was carried out. Faster uptake
of copper ion was obtained with the fired clay pellets of 5 mm
diameter size within 30 minutes. The pellets of 8 mm diameter size
showed the higher equilibrium time (60 to 75 minutes) for copper and
zinc ion. The results pointed out that adsorption efficiency increases
with the increase of adsorbent mass. The maximal efficiency is
different for Cu(II) and Zn(II) ion due to the pellet size. Therefore,
the fired clay pellets of 5 mm diameter size present an effective
adsorbent for Cu(II) ion removal (adsorption efficiency is 63.6%),
whereas the fired clay pellets of 8 mm diameter size are the best
alternative for Zn(II) ion removal (adsorption efficiency is 92.8%)
from a waste printing developer.
Abstract: Digital image correlation (DIC) is a contactless fullfield
displacement and strain reconstruction technique commonly
used in the field of experimental mechanics. Comparing with
physical measuring devices, such as strain gauges, which only
provide very restricted coverage and are expensive to deploy widely,
the DIC technique provides the result with full-field coverage and
relative high accuracy using an inexpensive and simple experimental
setup. It is very important to study the natural patterns effect on the
DIC technique because the preparation of the artificial patterns is
time consuming and hectic process. The objective of this research is
to study the effect of using images having natural pattern on the
performance of DIC. A systematical simulation method is used to
build simulated deformed images used in DIC. A parameter (subset
size) used in DIC can have an effect on the processing and accuracy
of DIC and even cause DIC to failure. Regarding to the picture
parameters (correlation coefficient), the higher similarity of two
subset can lead the DIC process to fail and make the result more
inaccurate. The pictures with good and bad quality for DIC methods
have been presented and more importantly, it is a systematic way to
evaluate the quality of the picture with natural patterns before they
install the measurement devices.
Abstract: The contact resistance between source/drain electrodes
and semiconductor layer is an important parameter affecting electron
transporting performance in the thin film transistor (TFT). In this
work, we introduced a transparent and the solution prossable
single-walled carbon nanotube (SWCNT)/Al-doped ZnO nano particle
(AZO NP) bilayer electrodes showing low contact resistance with
indium-oxide (In2O3) sol gel thin film. By inserting low work function
AZO NPs into the interface between the SWCNTs and the In2O3 which
has a high energy barrier, we could obtain an electrical Ohmic contact
between them. Finally, with the SWCNT-AZO NP bilayer electrodes,
we successfully fabricated a TFT showing a field effect mobility of
5.38 cm2/V·s at 250°C.
Abstract: Food is widely packaged with plastic materials to
prevent microbial contamination and spoilage. Ionizing radiation is
widely used to sterilize the food-packaging materials. Sterilization by
γ-radiation causes degradation such as embrittlement, stiffening,
softening, discoloration, odour generation, and decrease in molecular
weight. Many antioxidants can prevent γ-degradation but most of
them are toxic. The migration of antioxidants to its environment
gives rise to major concerns in case of food packaging plastics. In
this attempt, we have aimed to utilize synergistic mixtures of
stabilizers which are approved for food-contact applications.
Ethylene-propylene-diene terpolymer has been melt-mixed with
hindered amine stabilizers (HAS), phenolic antioxidants and organophosphites
(hydroperoxide decomposer). Results were discussed by
comparing the stabilizing efficiency of mixtures with and without
phenol system. Among phenol containing systems where we mostly
observed discoloration due to the oxidation of hindered phenol, the
combination of secondary HAS, tertiary HAS, organo-phosphite and
hindered phenol exhibited improved stabilization efficiency than
single or binary additive systems. The mixture of secondary HAS and
tertiary HAS, has shown antagonistic effect of stabilization.
However, the combination of organo-phosphite with secondary HAS,
tertiary HAS and phenol antioxidants have been found to give
synergistic even at higher doses of Gamma-irradiation. The effects
have been explained through the interaction between the stabilizers.
After γ-irradiation, the consumption of oligomeric stabilizer
significantly depends on the components of stabilization mixture. The
effect of the organo-phosphite antioxidant on the overall stability has
been discussed.
Abstract: Content-based image retrieval (CBIR) uses the
contents of images to characterize and contact the images. This paper
focus on retrieving the image by separating images into its three color
mechanism R, G and B and for that Discrete Wavelet Transformation
is applied. Then Wavelet based Generalized Gaussian Density (GGD)
is practical which is used for modeling the coefficients from the
wavelet transforms. After that it is agreed to Histogram of Oriented
Gradient (HOG) for extracting its characteristic vectors with Relevant
Feedback technique is used. The performance of this approach is
calculated by exactness and it confirms that this method is wellorganized
for image retrieval.
Abstract: The effect of the inclusion of thyme and rosemary
essential oils into chitosan films, as well as the microbiological and
physical properties when storing chitosan film with and without the
mentioned inclusion was studied. The film forming solution was
prepared by dissolving chitosan (2%, w/v), polysorbate 80 (4% w/w
CH) and glycerol (16% w/w CH) in aqueous lactic acid solutions
(control). The thyme (TEO) and rosemary (REO) essential oils (EOs)
were included 1:1 w/w (EOs:CH) on their combination 50/50
(TEO:REO). The films were stored at temperatures of 5, 20, 33°C
and a relative humidity of 75% during four weeks. The films with
essential oil inclusion did not show an antimicrobial activity against
strains. This behavior could be explained because the chitosan only
inhibits the growth of microorganisms in direct contact with the
active sites. However, the inhibition capacity of TEO was higher than
the REO and a synergic effect between TEO:REO was found for S.
enteritidis strains in the chitosan solution.
Some physical properties were modified by the inclusion of
essential oils. The addition of essential oils does not affect the
mechanical properties (tensile strength, elongation at break, puncture
deformation), the water solubility, the swelling index nor the DSC
behavior. However, the essential oil inclusion can significantly
decrease the thickness, the moisture content, and the L* value of
films whereas the b* value increased due to molecular interactions
between the polymeric matrix, the loosing of the structure, and the
chemical modifications. On the other hand, the temperature and time
of storage changed some physical properties on the chitosan films.
This could have occurred because of chemical changes, such as
swelling in the presence of high humidity air and the reacetylation of
amino groups. In the majority of cases, properties such as moisture
content, tensile strength, elongation at break, puncture deformation,
a*, b*, chrome, 7E increased whereas water resistance, swelling
index, L*, and hue angle decreased.
Abstract: The purpose of this paper is to examine gas transport
behavior of mixed matrix membranes (MMMs) combined with
porous particles. Main existing models are categorized in two main
groups; two-phase (ideal contact) and three-phase (non-ideal contact).
A new coefficient, J, was obtained to express equations for estimating
effect of the particle porosity in two-phase and three-phase models.
Modified models evaluates with existing models and experimental
data using Matlab software. Comparison of gas permeability of
proposed modified models with existing models in different MMMs
shows a better prediction of gas permeability in MMMs.
Abstract: The thermal conductivity of a fluid can be
significantly enhanced by dispersing nano-sized particles in it, and
the resultant fluid is termed as "nanofluid". A theoretical model for
estimating the thermal conductivity of a nanofluid has been proposed
here. It is based on the mechanism that evenly dispersed
nanoparticles within a nanofluid undergo Brownian motion in course
of which the nanoparticles repeatedly collide with the heat source.
During each collision a rapid heat transfer occurs owing to the solidsolid
contact. Molecular dynamics (MD) simulation of the collision
of nanoparticles with the heat source has shown that there is a pulselike
pick up of heat by the nanoparticles within 20-100 ps, the extent
of which depends not only on thermal conductivity of the
nanoparticles, but also on the elastic and other physical properties of
the nanoparticle. After the collision the nanoparticles undergo
Brownian motion in the base fluid and release the excess heat to the
surrounding base fluid within 2-10 ms. The Brownian motion and
associated temperature variation of the nanoparticles have been
modeled by stochastic analysis. Repeated occurrence of these events
by the suspended nanoparticles significantly contributes to the
characteristic thermal conductivity of the nanofluids, which has been
estimated by the present model for a ethylene glycol based nanofluid
containing Cu-nanoparticles of size ranging from 8 to 20 nm, with
Gaussian size distribution. The prediction of the present model has
shown a reasonable agreement with the experimental data available
in literature.
Abstract: In this research, waterglass based aerogel powder was
prepared by sol–gel process and ambient pressure drying. Inspired by
limited dust releasing, aerogel powder was introduced to the PET
electrospinning solution in an attempt to create required bulk and
surface structure for the nanofibers to improve their hydrophobic and
insulation properties. The samples evaluation was carried out by
measuring density, porosity, contact angle, heat transfer, FTIR, BET,
and SEM. According to the results, porous silica aerogel powder was
fabricated with mean pore diameter of 24 nm and contact angle of
145.9º. The results indicated the usefulness of the aerogel powder
confined into nanofibers to control surface roughness for
manipulating superhydrophobic nanowebs with water contact angle
of 147º. It can be due to a multi-scale surface roughness which was
created by nanowebs structure itself and nanofibers surface
irregularity in presence of the aerogels while a layer of fluorocarbon
created low surface energy. The wettability of a solid substrate is an
important property that is controlled by both the chemical
composition and geometry of the surface. Also, a decreasing trend in
the heat transfer was observed from 22% for the nanofibers without
any aerogel powder to 8% for the nanofibers with 4% aerogel
powder. The development of thermal insulating materials has become
increasingly more important than ever in view of the fossil energy
depletion and global warming that call for more demanding energysaving
practices.
Abstract: This paper presents observations on the early
supervised internships in Psychology, currently called basic
internships in Brazil, and its importance in professional training. The
work is an experience report and focuses on the Professional training,
illustrated by the reality of a Brazilian institution, used as a case
study. It was developed from the authors' experience as academic
supervisors of this kind of practice throughout this undergraduate
course, combined with aspects investigated in the post-doctoral
research of one of them. Theoretical references on the subject and
related national legislation are analyzed, as well as reports of students
who experienced at least one semester of this type of practice,
articulated to the observations of the authors. The results demonstrate
the importance of the early supervised internships as a way of
creating opportunities for the students of a first contact with the
professional reality and the practice of psychologists in different
fields of insertion, preparing them for further experiments that require
more involvement in activities of training and practices in
Psychology.
Abstract: Corrosion inhibitors are widely used in concrete
industry to reduce the corrosion rate of steel rebar which is present in
contact with aggressive environments. The present work aims to
using Zamzam water from well located within the Masjid al-Haram
in Mecca, Saudi Arabia 20 m (66 ft) east of the Kaaba, the holiest
place in Islam as corrosion inhibitor for steel in rain water and
simulated acid rain. The effect of Zamzam water was investigated by
electrochemical impedance spectroscopy (EIS) and Potentiodynamic
polarization techniques in Department of Civil Engineering - IUT
Saint-Nazaire, Nantes University, France. Zamzam water is
considered to be one of the most important steel corrosion inhibitor
which is frequently used in different industrial applications. Results
showed that zamzam water gave a very good inhibition for steel
corrosion in rain water and simulated acid rain.
Abstract: E-service quality plays a significant role to achieve
success or failure in any organization, offering services online. It will
increase the competition among the organizations, to attract the
customers on the basis of the quality of service provided by the
organization. Better e-service quality will enhance the relationship
with customers and their satisfaction. So the measurement of eservice
quality is very important but it is a complex process due to
the complex nature of services. Literature predicts that there is a lack
of universal definition of e-service quality. The e-service quality
measures in banking have great importance in achieving high
customer base. This paper proposes a conceptual model for
measuring e-service quality in Indian Banking Industry. Nine
dimensions reliability, ease of use, personalization, security and trust,
website aesthetic, responsiveness, contact and fulfillment had been
identified. The results of this paper may help to develop a proper
scale to measure the e-service quality in Indian Banking Industry,
which may assist to maintain and improve the performance and
effectiveness of e-service quality to retain customers.
Abstract: Laser beam welding for the dissimilar Titanium and
Aluminium thin sheets is an emerging area which is having wider
applications in aerospace, aircraft, automotive, electronics and in
other industries due to its high speed, non-contact, precision with low
heat effects, least welding distortion, low labor costs and convenient
operation. Laser beam welding of dissimilar metal combinations are
increasingly demanded due to high energy densities with small fusion
and heat affected zones. Furthermore, no filler or electrode material is
required and contamination of weld is also very small. The present
study is to reviews the influence of different parameters like laser
power, welding speed, power density, beam diameter, focusing
distance and type of shielding gas on the mechanical properties of
dissimilar metal combinations like SS/Al, Cu/Al and Ti/Al focusing
on aluminum to other materials. Research findings reveal that Ti/Al
combination gives better metallurgical and mechanical properties
than other combinations such as SS/Al and Cu/Al.
Abstract: The efficiency of wood vinegar mixed with each
individual of three plants extract such as: citronella grass
(Cymbopogon nardus), neem seed (Azadirachta indica A. Juss), and
yam bean seed (Pachyrhizus erosus Urb.) were tested against the
second instar larvae of housefly (Musca domestica L.). Steam
distillation was used for extraction of the citronella grass while neem
and yam bean were simple extracted by fermentation with ethyl
alcohol. Toxicity test was evaluated in laboratory based on two
methods of larvicidal bioassay: topical application method (contact
poison) and feeding method (stomach poison). Larval mortality was
observed daily and larval survivability was recorded until the
survived larvae developed to pupae and adults. The study resulted
that treatment of wood vinegar mixed with citronella grass showed
the highest larval mortality by topical application method (50.0%)
and by feeding method (80.0%). However, treatment of mixed wood
vinegar and neem seed showed the longest pupal duration to 25 day
and 32 days for topical application method and feeding method
respectively. Additional, larval duration on treated M. domestica
larvae was extended to 13 days for topical application method and 11
days for feeding method. Thus, the feeding method gave higher
efficiency compared with the topical application method.
Abstract: The substantial similarity of fatigue mechanism in a
new test rig for rolling contact fatigue (RCF) has been investigated. A
new reduced-scale test rig is designed to perform controlled RCF
tests in wheel-rail materials. The fatigue mechanism of the rig is
evaluated in this study using a combined finite element-fatigue
prediction approach. The influences of loading conditions on fatigue
crack initiation have been studied. Furthermore, the effects of some
artificial defects (squat-shape) on fatigue lives are examined. To
simulate the vehicle-track interaction by means of the test rig, a threedimensional
finite element (FE) model is built up. The nonlinear
material behaviour of the rail steel is modelled in the contact
interface. The results of FE simulations are combined with the critical
plane concept to determine the material points with the greatest
possibility of fatigue failure. Based on the stress-strain responses, by
employing of previously postulated criteria for fatigue crack initiation
(plastic shakedown and ratchetting), fatigue life analysis is carried
out. The results are reported for various loading conditions and
different defect sizes. Afterward, the cyclic mechanism of the test rig
is evaluated from the operational viewpoint. The results of fatigue
life predictions are compared with the expected number of cycles of
the test rig by its cyclic nature. Finally, the estimative duration of the
experiments until fatigue crack initiation is roughly determined.