Abstract: Erosion and abrasion are wear mechanisms reducing
the lifetime of machine elements like valves, pump and pipe systems.
Both wear mechanisms are acting at the same time, causing a
“Synergy” effect, which leads to a rapid damage of the surface.
Different parameters are effective on erosive abrasive wear rate. In
this study effect of particle impact angle on wear rate and wear
mechanism of ductile and brittle materials was investigated. A new
slurry pot was designed for experimental investigation. As abrasive
particle, silica sand was used. Particle size was ranking between 200-
500 μm. All tests were carried out in a sand-water mixture of 20%
concentration for four hours. Impact velocities of the particles were
4.76 m/s. As ductile material steel St 37 with Vickers Hardness
Number (VHN) of 245 and quenched St 37 with 510 VHN was used
as brittle material. After wear tests, morphology of the eroded
surfaces were investigated for better understanding of the wear
mechanisms acting at different impact angles by using Scanning
Electron Microscope. The results indicated that wear rate of ductile
material was higher than brittle material. Maximum wear rate was
observed by ductile material at a particle impact angle of 300 and
decreased further by an increase in attack angle. Maximum wear rate
by brittle materials was by impact angle of 450 and decreased further
up to 900. Ploughing was the dominant wear mechanism by ductile
material. Microcracks on the surface were detected by ductile
materials, which are nucleation centers for crater formation. Number
of craters decreased and depth of craters increased by ductile
materials by attack angle higher than 300. Deformation wear
mechanism was observed by brittle materials. Number and depth of
pits decreased by brittle materials by impact angles higher than 450.
At the end it is concluded that wear rate could not be directly related
to impact angle of particles due to the different reaction of ductile and
brittle materials.
Abstract: Sweden has succeeded to maintain a high level of
growth and development and has managed to sustain highly ranked
position among the world’s developed countries. In this regard,
Swedish universities are playing a vital role in supporting innovation
and entrepreneurship at all levels and developing Swedish knowledge
economy. This paper is aiming to draw on the experiences of two leading
Swedish universities, addressing their transformation approach to
create entrepreneurial universities and fulfilling their objectives in the
era of knowledge economy. The objectives of the paper include: 1) Introducing the Swedish
higher education and its characteristics. 2) Examining the
infrastructure elements for innovation and Entrepreneurship at two of
the Swedish entrepreneurial universities. 3) Addressing the key
aspects of support systems in the initiatives of both Chalmers and
Gothenburg universities to support innovation and advance
entrepreneurial practices. The paper will contribute to two discourses: 1) Examining the
relationship between support systems for innovation and
entrepreneurship and the Universities’ policies and practices. 2)
Lessons for University leaders to assist the development and
implementation of effective innovation and entrepreneurship policies
and practices.
Abstract: Web mining is to discover and extract useful
Information. Different users may have different search goals when
they search by giving queries and submitting it to a search engine.
The inference and analysis of user search goals can be very useful for
providing an experience result for a user search query. In this project,
we propose a novel approach to infer user search goals by analyzing
search web logs. First, we propose a novel approach to infer user
search goals by analyzing search engine query logs, the feedback
sessions are constructed from user click-through logs and it
efficiently reflect the information needed for users. Second we
propose a preprocessing technique to clean the unnecessary data’s
from web log file (feedback session). Third we propose a technique
to generate pseudo-documents to representation of feedback sessions
for clustering. Finally we implement k-medoids clustering algorithm
to discover different user search goals and to provide a more optimal
result for a search query based on feedback sessions for the user.
Abstract: The aim of the current work was to employ the finite
element method to model a slab, with a small hole across its width,
undergoing plastic plane strain deformation. The computational
model had, however, to be validated by comparing its results with
those obtained experimentally. Since they were in good agreement,
the finite element method can therefore be considered a reliable tool
that can help gain better understanding of the mechanism of ductile
failure in structural members having stress raisers. The finite element
software used was ANSYS, and the PLANE183 element was utilized.
It is a higher order 2-D, 8-node or 6-node element with quadratic
displacement behavior. A bilinear stress-strain relationship was used
to define the material properties, with constants similar to those of the
material used in the experimental study. The model was run for
several tensile loads in order to observe the progression of the plastic
deformation region, and the stress concentration factor was
determined in each case. The experimental study involved employing the visioplasticity
technique, where a circular mesh (each circle was 0.5 mm in
diameter, with 0.05 mm line thickness) was initially printed on the
side of an aluminum slab having a small hole across its width.
Tensile loading was then applied to produce a small increment of
plastic deformation. Circles in the plastic region became ellipses,
where the directions of the principal strains and stresses coincided
with the major and minor axes of the ellipses. Next, we were able to
determine the directions of the maximum and minimum shear
stresses at the center of each ellipse, and the slip-line field was then
constructed. We were then able to determine the stress at any point in
the plastic deformation zone, and hence the stress concentration
factor. The experimental results were found to be in good agreement
with the analytical ones.
Abstract: One of the most critical decision points in the design of a
face recognition system is the choice of an appropriate face representation.
Effective feature descriptors are expected to convey sufficient, invariant
and non-redundant facial information. In this work we propose a set of
Hahn moments as a new approach for feature description. Hahn moments
have been widely used in image analysis due to their invariance, nonredundancy
and the ability to extract features either globally and locally.
To assess the applicability of Hahn moments to Face Recognition we
conduct two experiments on the Olivetti Research Laboratory (ORL)
database and University of Notre-Dame (UND) X1 biometric collection.
Fusion of the global features along with the features from local facial
regions are used as an input for the conventional k-NN classifier. The
method reaches an accuracy of 93% of correctly recognized subjects for
the ORL database and 94% for the UND database.
Abstract: Standard Gibbs energy of formation ΔGfor(298.15) of
lanthanide-iron double oxides of garnet-type crystal structure
R3Fe5O12 - RIG (R – are rare earth ions) from initial oxides are
evaluated. The calculation is based on the data of standard entropies
S298.15 and standard enthalpies ΔH298.15 of formation of compounds
which are involved in the process of garnets synthesis. Gibbs energy
of formation is presented as temperature function ΔGfor(T) for the
range 300-1600K. The necessary starting thermodynamic data were
obtained from calorimetric study of heat capacity – temperature
functions and by using the semi-empirical method for calculation of
ΔH298.15 of formation. Thermodynamic functions for standard
temperature – enthalpy, entropy and Gibbs energy - are
recommended as reference data for technological evaluations.
Through the structural series of rare earth-iron garnets the correlation
between thermodynamic properties and characteristics of lanthanide
ions are elucidated.
Abstract: Synthesis of gold nanoparticles has attracted much
attention since the pioneering discovery of the high catalytic activity
of supported gold nanoparticles in the reaction of CO oxidation at
low temperature. In this research field, we used Na-montmorillonite
for gold nanoparticles stabilization; various gold loading percentage
1, 2 and 5% were used for gold nanoparticles preparation. The gold
nanoparticles were obtained using chemical reduction method using
NaBH4 as reductant agent. The obtained gold nanoparticles stabilized
in Na-montmorillonite were used as catalysts for the reduction of 4-
nitrophenol to aminophenol with sodium borohydride at room
temperature. The UV-Vis results confirmed directly the gold
nanoparticles formation. The XRD and N2 adsorption results showed
the formation of gold nanoparticles in the pores of montmorillonite
with an average size of 5 nm obtained on samples with 2% gold
loading percentage. The gold particles size increased with the
increase of gold loading percentage. The reduction reaction of 4-
nitrophenol into 4-aminophenol with NaBH4 catalyzed by Au-Namontmorillonite
catalyst exhibits remarkably a high activity; the
reaction was completed within 9 min for 1%Au-Na-montmorillonite
and within 3 min for 2%Au-Na-montmorillonite.
Abstract: Geographical routing protocol requires node physical
location information to make forwarding decision. Geographical
routing uses location service or position service to obtain the position
of a node. The geographical information is a geographic coordinates
or can be obtained through reference points on some fixed coordinate
system. Link can be formed between two nodes. Link lifetime plays a
crucial role in MANET. Link lifetime represent how long the link is
stable without any failure between the nodes. Link failure may occur
due to mobility and because of link failure energy of nodes can be
drained. Thus this paper proposes survey about link lifetime
prediction using geographical information.
Abstract: In this paper, analysis of an infinite beam resting on
multilayer tensionless extensible geosynthetic reinforced granular
fill-poor soil system overlying soft soil strata under moving load with
constant velocity is presented. The beam is subjected to a
concentrated load moving with constant velocity. The upper
reinforced granular bed is modeled by a rough membrane embedded
in Pasternak shear layer overlying a series of compressible nonlinear
winkler springs representing the underlying the very poor soil. The
multilayer tensionless extensible geosynthetic layer has been
assumed to deform such that at interface the geosynthetic and the soil
have some deformation. Nonlinear behaviour of granular fill and the
very poor soil has been considered in the analysis by means of
hyperbolic constitutive relationships. Governing differential
equations of the soil foundation system have been obtained and
solved with the help of appropriate boundary conditions. The solution
has been obtained by employing finite difference method by means of
Gauss-Siedal iterative scheme. Detailed parametric study has been
conducted to study the influence of various parameters on the
response of soil–foundation system under consideration by means of
deflection and bending moment in the beam and tension mobilized in
the geosynthetic layer. These parameters include magnitude of
applied load, velocity of load, damping, ultimate resistance of poor
soil and granular fill layer. Range of values of parameters has been
considered as per Indian Railway conditions. This study clearly
observed that the comparisons of multilayer tensionless extensible
geosynthetic reinforcement with poor foundation soil and magnitude
of applied load, relative compressibility of granular fill and ultimate
resistance of poor soil has significant influence on the response of
soil–foundation system.
Abstract: In recent years, fire accidents have been steadily
increased and the amount of property damage caused by the accidents
has gradually raised. Damaging building structure, fire incidents bring
about not only such property damage but also strength degradation and
member deformation. As a result, the building structure undermines its
structural ability. Examining the degradation and the deformation is
very important because reusing the building is more economical than
reconstruction. Therefore, engineers need to investigate the strength
degradation and member deformation well, and make sure that they
apply right rehabilitation methods. This study aims at evaluating
deformation characteristics of fire damaged and rehabilitated normal
strength concrete beams through both experiments and finite element
analyses. For the experiments, control beams, fire damaged beams and
rehabilitated beams are tested to examine deformation characteristics.
Ten test beam specimens with compressive strength of 21MPa are
fabricated and main test variables are selected as cover thickness of
40mm and 50mm and fire exposure time of 1 hour or 2 hours. After
heating, fire damaged beams are air-recurred for 2 months and
rehabilitated beams are repaired with polymeric cement mortar after
being removed the fire damaged concrete cover. All beam specimens
are tested under four points loading. FE analyses are executed to
investigate the effects of main parameters applied to experimental
study. Test results show that both maximum load and stiffness of the
rehabilitated beams are higher than those of the fire damaged beams.
In addition, predicted structural behaviors from the analyses also show
good rehabilitation effect and the predicted load-deflection curves are
similar to the experimental results. For the further, the proposed
analytical method can be used to predict deformation characteristics of
fire damaged and rehabilitated concrete beams without suffering from
time and cost consuming of experimental process.
Abstract: The article describes the effect of the replacement of
the used reference coordinate system in the georeferencing of an old
map of Europe. The map was georeferenced into three types of
projection – the equal-area conic (original cartographic projection),
cylindrical Plate Carrée and cylindrical Mercator map projection. The
map was georeferenced by means of the affine and the second-order
polynomial transformation. The resulting georeferenced raster
datasets from the Plate Carrée and Mercator projection were
projected into the equal-area conic projection by means of projection
equations. The output is the comparison of drawn graphics, the
magnitude of standard deviations for individual projections and types
of transformation.
Abstract: In present global scenario, aluminum alloys are
coining the attention of many innovators as competing structural
materials for automotive and space applications. Comparing to other
challenging alloys, especially, 7xxx series aluminum alloys have
been studied seriously because of benefits such as moderate strength;
better deforming characteristics and affordable cost. It is expected
that substitution of aluminum alloys for steels will result in great
improvements in energy economy, durability and recyclability.
However, it is necessary to improve the strength and the formability
levels at low temperatures in aluminum alloys for still better
applications. Aluminum–Zinc–Magnesium with or without other
wetting agent denoted as 7XXX series alloys are medium strength
heat treatable alloys. In addition to Zn, Mg as major alloying
additions, Cu, Mn and Si are the other solute elements which
contribute for the improvement in mechanical properties by suitable
heat treatment process. Subjecting to suitable treatments like age
hardening or cold deformation assisted heat treatments; known as low
temperature thermomechanical treatments (LTMT) the challenging
properties might be incorporated. T6 is the age hardening or
precipitation hardening process with artificial aging cycle whereas T8
comprises of LTMT treatment aged artificially with X% cold
deformation. When the cold deformation is provided after solution
treatment, there is increase in hardness related properties such as
wear resistance, yield and ultimate strength, toughness with the
expense of ductility. During precipitation hardening both hardness
and strength of the samples are increasing. The hardness value may
further improve when room temperature deformation is positively
supported with age hardening known as thermomechanical treatment.
It is intended to perform heat treatment and evaluate hardness, tensile
strength, wear resistance and distribution pattern of reinforcement in
the matrix. 2 to 2.5 and 3 to 3.5 times increase in hardness is reported
in age hardening and LTMT treatments respectively as compared to
as-cast composite. There was better distribution of reinforcements in
the matrix, nearly two fold increase in strength levels and up to 5
times increase in wear resistance are also observed in the present
study.
Abstract: The work aims to develop a robot in the form of
autonomous vehicle to detect, inspection and mapping of
underground pipelines through the ATmega328 Arduino platform.
Hardware prototyping is very similar to C / C ++ language that
facilitates its use in robotics open source, resembles PLC used in
large industrial processes. The robot will traverse the surface
independently of direct human action, in order to automate the
process of detecting buried pipes, guided by electromagnetic
induction. The induction comes from coils that send the signal to the
Arduino microcontroller contained in that will make the difference in
intensity and the treatment of the information, and then this
determines actions to electrical components such as relays and
motors, allowing the prototype to move on the surface and getting the
necessary information. This change of direction is performed by a
stepper motor with a servo motor. The robot was developed by
electrical and electronic assemblies that allowed test your application.
The assembly is made up of metal detector coils, circuit boards and
microprocessor, which interconnected circuits previously developed
can determine, process control and mechanical actions for a robot
(autonomous car) that will make the detection and mapping of buried
pipelines plates. This type of prototype can prevent and identifies
possible landslides and they can prevent the buried pipelines suffer an
external pressure on the walls with the possibility of oil leakage and
thus pollute the environment.
Abstract: The rapid growth of multimedia technology demands
the secure and efficient access to information. This fast growing lose
the confidence of unauthorized duplication. Henceforth the protection
of multimedia content is becoming more important. Watermarking
solves the issue of unlawful copy of advanced data. In this paper,
blind video watermarking technique has been proposed. A luminance
layer of selected frames is interlaced into two even and odd rows of
an image, further it is deinterlaced and equalizes the coefficients of
the two shares. Color watermark is split into different blocks, and the
pieces of block are concealed in one of the share under the wavelet
transform. Stack the two images into a single image by introducing
interlaced even and odd rows in the two shares. Finally, chrominance
bands are concatenated with the watermarked luminance band. The
safeguard level of the secret information is high, and it is
undetectable. Results show that the quality of the video is not
changed also yields the better PSNR values.
Abstract: Experimental investigations of the DC electric field effect on thermal decomposition of biomass, formation of the axial flow of volatiles (CO, H2, CxHy), mixing of volatiles with swirling airflow at low swirl intensity (S ≈ 0.2-0.35), their ignition and on formation of combustion dynamics are carried out with the aim to understand the mechanism of electric field influence on biomass gasification, combustion of volatiles and heat energy production. The DC electric field effect on combustion dynamics was studied by varying the positive bias voltage of the central electrode from 0.6 kV to 3 kV, whereas the ion current was limited to 2 mA. The results of experimental investigations confirm the field-enhanced biomass gasification with enhanced release of volatiles and the development of endothermic processes at the primary stage of thermochemical conversion of biomass determining the field-enhanced heat energy consumption with the correlating decrease of the flame temperature and heat energy production at this stage of flame formation. Further, the field-enhanced radial expansion of the flame reaction zone correlates with a more complete combustion of volatiles increasing the combustion efficiency by 3% and decreasing the mass fraction of CO, H2 and CxHy in the products, whereas by 10% increases the average volume fraction of CO2 and the heat energy production downstream the combustor increases by 5-10%
Abstract: This paper presents a method of evaluating the effect
of aggregate angularity on hot mix asphalt (HMA) properties and its
relationship to the Permanent Deformation resistance. The research
concluded that aggregate particle angularity had a significant effect
on the Permanent Deformation performance, and also that with an
increase in coarse aggregate angularity there was an increase in the
resistance of mixes to Permanent Deformation. A comparison
between the measured data and predictive data of permanent
deformation predictive models showed the limits of existing
prediction models. The numerical analysis described the permanent
deformation zones and concluded that angularity has an effect of the
onset of these zones. Prediction of permanent deformation help road
agencies and by extension economists and engineers determine the
best approach for maintenance, rehabilitation, and new construction
works of the road infrastructure.
Abstract: The aim of this study is to investigate formability of
Al based closed cell metallic foams at high temperature. The foam
specimens with rectangular section were produced from
AlMg1Si0.6TiH20.8 alloy preform material. Bending and free
bending tests based on gravity effect were applied to foam specimens
at high temperatures. During the tests, the time-angular deformation
relationships with various temperatures were determined.
Deformation types formed in cell walls were investigated by means
of Scanning Electron Microscopy (SEM) and optical microscopy.
Bending deformation about 90° was achieved without any defect at
high temperatures. The importance of a critical temperature and
deformation rate was emphasized in maintaining the deformation.
Significant slip lines on surface of cell walls at tensile zones of
bending specimen were observed. At high strain rates, the microcrack
formation in boundaries of elongated grains was determined.
Abstract: This paper contains the description of argumentation
approach for the problem of inductive concept formation. It is
proposed to use argumentation, based on defeasible reasoning with
justification degrees, to improve the quality of classification models,
obtained by generalization algorithms. The experiment’s results on
both clear and noisy data are also presented.
Abstract: In this research numerical simulations are performed,
using the multi-relaxation-time lattice Boltzmann method, in the
range 3 ≤ β = w[d] ≤ 30 at Re = 100, 200 and 300, where β the
blockage ratio, w is the equispaced distance between centers of
cylinders, d is the diameter of the cylinder and Re is the Reynolds
number, respectively. Special attention is paid to the effect of the
equispaced distance between centers of cylinders. Visualization of
the vorticity contour visualization are presented for some simulation
showing the flow dynamics and patterns for blockage effect. Results
show that the drag and mean drag coefficients, and Strouhal number,
in general, decrease with the increase of β for fixed Re. It is found
that the decreasing rate of drag and mean drag coefficients and
Strouhal number is more distinct in the range 3 ≤ β ≤ 15. We found
that when β > 15, the blockage effect almost diminishes. Our results
further indicate that the drag and mean drag coefficients, peak value
of the lift coefficient, root-mean-square value of the lift and drag
coefficients and the ratio between lift and drag coefficients decrease
with the increase of Re. The results indicate that symmetry boundary
condition have more blockage effect as compared to periodic
boundary condition.
Abstract: Crosstalk among interconnects and printed-circuit
board (PCB) traces is a major limiting factor of signal quality in highspeed
digital and communication equipments especially when fast
data buses are involved. Such a bus is considered as a planar
multiconductor transmission line. This paper will demonstrate how
the finite difference time domain (FDTD) method provides an exact
solution of the transmission-line equations to analyze the near end
and the far end crosstalk. In addition, this study makes it possible to
analyze the rise time effect on the near and far end voltages of the
victim conductor. The paper also discusses a statistical analysis,
based upon a set of several simulations. Such analysis leads to a
better understanding of the phenomenon and yields useful
information.