Abstract: In recent years, the use of the aluminum based alloys
in the industry and technology are increasing. Alloying elements in
aluminum have further been improving the strength and stiffness
properties that provide superior compared to other metals. In this
study, investigation of physical properties (microstructure,
microhardness, tensile strength, electrical conductivity and thermal
properties) in the Al-12.6wt.%Si-%2wt.Ni ternary alloy were
investigated. Al-Si-Ni alloy was prepared in vacuum atmosphere. The
samples were directionally solidified upwards with different growth
rate V (8.3−165.45 μm/s) at constant temperature gradient G (7.73
K/mm). The flake spacings (λ), microhardness (HV), ultimate tensile
strength (σ), electrical resistivity (ρ) and thermal properties (H, Cp,
Tm) of the samples were measured. Influence of the growth rate and
spacings on microhardness, ultimate tensile strength and electrical
resistivity were investigated and relationships between them were
obtained. According to results, λ values decrease with increasing V,
but HV, σ and ρ values increase with increasing V. Variations of
electrical resistivity (ρ) of solidified samples were also measured.
The enthalpy of fusion (H) and specific heat (Cp) for the alloy was
also determined by differential scanning calorimeter (DSC) from
heating trace during the transformation from liquid to solid. The
results in this work were compared with the previous similar
experimental results.
Abstract: The localization information is crucial for the
operation of WSN. There are principally two types of localization
algorithms. The Range-based localization algorithm has strict
requirements on hardware, thus is expensive to be implemented in
practice. The Range-free localization algorithm reduces the hardware
cost. However, it can only achieve high accuracy in ideal scenarios.
In this paper, we locate unknown nodes by incorporating the
advantages of these two types of methods. The proposed algorithm
makes the unknown nodes select the nearest anchor using the
Received Signal Strength Indicator (RSSI) and choose two other
anchors which are the most accurate to achieve the estimated
location. Our algorithm improves the localization accuracy compared
with previous algorithms, which has been demonstrated by the
simulating results.
Abstract: The spindle system is one of the most important
components of machine tool. The dynamic properties of the spindle
affect the machining productivity and quality of the work pieces.
Thus, it is important and necessary to determine its dynamic
characteristics of spindles in the design and development in order to
avoid forced resonance. The finite element method (FEM) has been
adopted in order to obtain the dynamic behavior of spindle system.
For this reason, obtaining the Campbell diagrams and determining the
critical speeds are very useful to evaluate the spindle system
dynamics. The unbalance response of the system to the center of
mass unbalance at the cutting tool is also calculated to investigate the
dynamic behavior. In this paper, we used an ANSYS Parametric
Design Language (APDL) program which based on finite element
method has been implemented to make the full dynamic analysis and
evaluation of the results. Results show that the calculated critical
speeds are far from the operating speed range of the spindle, thus, the
spindle would not experience resonance, and the maximum
unbalance response at operating speed is still with acceptable limit.
ANSYS Parametric Design Language (APDL) can be used by spindle
designer as tools in order to increase the product quality, reducing
cost, and time consuming in the design and development stages.
Abstract: Drying is a phenomenon that accompanies the
hardening of hydraulic materials. This study is concerned the
modelling of drying shrinkage of the hydraulic materials and the
prediction of the rate of spontaneous deformations of hydraulic
materials during hardening. The model developed takes consideration
of the main factors affecting drying shrinkage. There was agreement
between drying shrinkage predicted by the developed model and
experimental results. In last we show that developed model describe
the evolution of the drying shrinkage of high performances concretes
correctly.
Abstract: In order to study the effect of different levels of triple
super phosphate chemical fertilizer and biological phosphate fertilizer
(fertile 2) on some morphological traits of corn this research was
carried out in Ahvaz in 2002 as a factorial experiment in randomized
complete block design with 4 replications). The experiment included
two factors: first, biological phosphate fertilizer (fertile 2) at three
levels of 0, 100, 200 g/ha; second, triple super phosphate chemical
fertilizer at three levels of 0, 60, 90 kg/ha of pure phosphorus (P2O5).
The obtained results indicated that fertilizer treatments had a
significant effect on some morphological traits at 1% probability
level. In this regard, P2B2 treatment (100 g/ha biological phosphate
fertilizer (fertile 2) and 60 kg/ha triple super phosphate fertilizer) had
the greatest plant height, stem diameter, number of leaves and ear
length. It seems that in Ahvaz weather conditions, decrease of
consumption of triple superphosphate chemical fertilizer to less than
a half along with the consumption of biological phosphate fertilizer
(fertile 2) is highly important in order to achieve optimal results.
Therefore, it can be concluded that biological fertilizers can be used
as a suitable substitute for some of the chemical fertilizers in
sustainable agricultural systems.
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: Since 1920, the industry has almost completely
changed the rivets production techniques for the manufacture of
permanent welding join production of structures and manufacture of
other products. The welding arc is the process more widely used in
industries. This is accomplished by the heat of an electric arc which
melts the base metal while the molten metal droplets are transferred
through the arc to the welding pool, protected from the atmosphere
by a gas curtain. The GMAW (Gas metal arc welding) process is
influenced by variables such as: current, polarity, welding speed,
electrode: extension, position, moving direction; type of joint,
welder's ability, among others. It is remarkable that the knowledge
and control of these variables are essential for obtaining satisfactory
quality welds, knowing that are interconnected so that changes in one
of them requiring changes in one or more of the other to produce the
desired results. The optimum values are affected by the type of base
metal, the electrode composition, the welding position and the quality
requirements. Thus, this paper proposes a new methodology, adding
the variable vibration through a mechanism developed for GMAW
welding, in order to improve the mechanical and metallurgical
properties which does not affect the ability of the welder and enables
repeatability of the welds made. For confirmation metallographic
analysis and mechanical tests were made.
Abstract: The paper provides a comprehensive analysis of the
sustainable development in the Belgrade Metropolitan Region - BMA
(level NUTS 2) preliminary evaluating the three chosen components:
1) economic growth and developmental changes; 2) competitiveness;
and 3) territorial concentration and industrial specialization. First, we
identified the main results of development changes and economic
growth by applying Shift-share analysis on the metropolitan level.
Second, the empirical evaluation of competitiveness in the BMA is
based on the analysis of absolute and relative values of eight
indicators by Spider method. Paper shows that the consideration of
the national share, industrial mix and metropolitan/regional share in
total Shift share of the BMA, as well as economic/functional
specialization of the BMA indicate very strong process of
deindustrialization. Allocative component of the BMA economic
growth has positive value, reflecting the above-average sector
productivity compared to the national average. Third, the important
positive role of metropolitan/regional component in decomposition of
the BMA economic growth is highlighted as one of the key results.
Finally, comparative analysis of the industrial territorial
concentration in the BMA in relation to Serbia is based on location
quotient (LQ) or Balassa index as a valid measure. The results
indicate absolute and relative differences in decrease of industry
territorial concentration as well as inefficiency of utilizing territorial
capital in the BMA. Results are important for the increase of regional
competitiveness and territorial distribution in this area as well as for
improvement of sustainable metropolitan and sector policies,
planning and governance on this level.
Abstract: Psyllium gum alone and in combination with
sunflower oil was investigated as a possible alternative edible coating
for improvement of quality and shelf life of fresh-cut papaya.
Different concentrations including 0.5, 1 and 1.5 percent of psyllium
gum were used for coating of fresh-cut papaya. In some samples,
refined sunflower oil was used as a lipid component to increase the
effectiveness of coating in terms of water barrier properties. Soya
lecithin was used as an emulsifier in coatings containing oil.
Pretreatment with 1% calcium chloride was given to maintain the
firmness of fresh-cut papaya cubes. 1% psyllium gum coating was
found to yield better results. Further, addition of oil helped to
maintain the quality and acted as a barrier to water vapour, therefore,
minimizing the weight loss.
Abstract: The elastic properties and fracture of two-dimensional
graphene were calculated purely from the atomic bonding (stretching
and bending) based on molecular mechanics method. Considering the
representative unit cell of graphene under various loading conditions,
the deformations of carbon bonds and the variations of the interlayer
distance could be realized numerically under the geometry constraints
and minimum energy assumption. In elastic region, it was found that
graphene was in-plane isotropic. Meanwhile, the in-plane deformation
of the representative unit cell is not uniform along armchair direction
due to the discrete and non-uniform distributions of the atoms. The
fracture of graphene could be predicted using fracture criteria based on
the critical bond length, over which the bond would break. It was
noticed that the fracture behavior were directional dependent, which
was consistent with molecular dynamics simulation results.
Abstract: Native American communities are struggling with unemployment and depressed economies. A major cause is a lack of business knowledge, education, and cultural desire. And yet, in the history of the American West, Native Americans were considered the best traders and negotiators for everything from furs to weapons to buffalo. To improve these economies, there has been an effort to reintroduce that heritage to todays and tomorrows generation of tribal members, such Crow, Cheyenne, and Blackfeet. Professors at the College of Business Montana State University-Billings (MSUB) teach tribal students in Montana to create business plans. These plans have won national small business plan competitions. The teaching and advising method used at MSUB is uniquely successful as theses business students are now five time national champions. This article reviews the environment and the method of learning to achieve a winning small business plan with Native American students. It discusses the five plans that became national champions. And it discusses the problems and solutions discovered in the process of achieving results. Students who participated in this endeavor have graduated and become CPAs, MBAs, and gainfully employed in their chosen professions. They have also worked to improve the economies of their native lands and homes. By educating members of these communities with business strategy and plan development, they are better able to impact their own economies.
Abstract: The Chair of Thermal Engineering at Poznan
University of Technology has been conducted research works on the
possibilities of using carbon nanostructures in energy and mechanics
applications for a couple of years. Those studies have provided results in a form of co-operation with foreign research centres, numerous publications and patent
applications.
Authors of this paper have studied the influence of multi-walled
carbon nanostructures on changes in static friction arising when steel
surfaces were moved. Tests were made using the original test stand
consisting of automatically controlled inclined plane driven by
precise stepper motors. Computer program created in the LabView
environment was responsible for monitoring of the stand operation,
accuracy of measurements and archiving the obtained results. Such a
solution enabled to obtain high accuracy and repeatability of all
conducted experiments.
Tests and analysis of the obtained results allowed us to determine
how additional layers of carbon nanostructures influenced on changes
of static friction coefficients. At the same time, we analyzed the
potential possibilities of applying nanostructures under consideration
in mechanics.
Abstract: In this paper, we investigated the athermal pressure
behavior of the structural and elastic properties of scheelite BaWO4
phase up to 7 GPa using the ab initio pseudo-potential method. The
calculated lattice parameters pressure relation have been compared
with the experimental values and found to be in good agreement with
these results. Moreover, we present for the first time the investigation
of the elastic properties of this compound using the density functional
perturbation theory (DFPT). It is shown that this phase is
mechanically stable up to 7 GPa after analyzing the calculated elastic
constants. Other relevant quantities such as bulk modulus, pressure
derivative of bulk modulus, shear modulus; Young’s modulus,
Poisson’s ratio, anisotropy factors, Debye temperature and sound
velocity have been calculated. The obtained results, which are
reported for the first time to the best of the author’s knowledge, can
facilitate assessment of possible applications of the title material.
Abstract: In this study, three robust predicting methods, namely artificial neural network (ANN), adaptive neuro fuzzy inference system (ANFIS) and support vector machine (SVM) were used for computing the resonant frequency of A-shaped compact microstrip antennas (ACMAs) operating at UHF band. Firstly, the resonant frequencies of 144 ACMAs with various dimensions and electrical parameters were simulated with the help of IE3D™ based on method of moment (MoM). The ANN, ANFIS and SVM models for computing the resonant frequency were then built by considering the simulation data. 124 simulated ACMAs were utilized for training and the remaining 20 ACMAs were used for testing the ANN, ANFIS and SVM models. The performance of the ANN, ANFIS and SVM models are compared in the training and test process. The average percentage errors (APE) regarding the computed resonant frequencies for training of the ANN, ANFIS and SVM were obtained as 0.457%, 0.399% and 0.600%, respectively. The constructed models were then tested and APE values as 0.601% for ANN, 0.744% for ANFIS and 0.623% for SVM were achieved. The results obtained here show that ANN, ANFIS and SVM methods can be successfully applied to compute the resonant frequency of ACMAs, since they are useful and versatile methods that yield accurate results.
Abstract: Boiling process is characterized by the rapid
formation of vapour bubbles at the solid–liquid interface (nucleate
boiling) with pre-existing vapour or gas pockets. Computational fluid
dynamics (CFD) is an important tool to study bubble dynamics. In
the present study, CFD simulation has been carried out to determine
the bubble detachment diameter and its terminal velocity. Volume of
fluid method is used to model the bubble and the surrounding by
solving single set of momentum equations and tracking the volume
fraction of each of the fluids throughout the domain. In the
simulation, bubble is generated by allowing water-vapour to enter a
cylinder filled with liquid water through an inlet at the bottom. After
the bubble is fully formed, the bubble detaches from the surface and
rises up during which the bubble accelerates due to the net balance
between buoyancy force and viscous drag. Finally when these forces
exactly balance each other, it attains a constant terminal velocity. The
bubble detachment diameter and the terminal velocity of the bubble
are captured by the monitor function provided in FLUENT. The
detachment diameter and the terminal velocity obtained are compared
with the established results based on the shape of the bubble. A good
agreement is obtained between the results obtained from simulation
and the equations in comparison with the established results.
Abstract: By the evolvement in technology, the way of
expressing opinions switched direction to the digital world. The
domain of politics, as one of the hottest topics of opinion mining
research, merged together with the behavior analysis for affiliation
determination in texts, which constitutes the subject of this paper.
This study aims to classify the text in news/blogs either as
Republican or Democrat with the minimum number of features. As
an initial set, 68 features which 64 were constituted by Linguistic
Inquiry and Word Count (LIWC) features were tested against 14
benchmark classification algorithms. In the later experiments, the
dimensions of the feature vector reduced based on the 7 feature
selection algorithms. The results show that the “Decision Tree”,
“Rule Induction” and “M5 Rule” classifiers when used with “SVM”
and “IGR” feature selection algorithms performed the best up to
82.5% accuracy on a given dataset. Further tests on a single feature
and the linguistic based feature sets showed the similar results. The
feature “Function”, as an aggregate feature of the linguistic category,
was found as the most differentiating feature among the 68 features
with the accuracy of 81% in classifying articles either as Republican
or Democrat.
Abstract: Submerged arc welding is a very complex process. It
is a very efficient and high performance welding process. In this
present study an attempt have been done to reduce the welding
distortion by increased amount of oxide flux through TiO2 in
submerged arc welding process. Care has been taken to avoid the
excessiveness of the adding agent for attainment of significant
results. Data Envelopment Analysis (DEA) based BAT algorithm is
used for the parametric optimization purpose in which DEA is used
to convert multi response parameters into a single response
parameter. The present study also helps to know the effectiveness of
the addition of TiO2 in active flux during submerged arc welding
process.
Abstract: The rationale behind this study is considering
combating and preventing the phenomenon of trafficking in human
beings from a multidisciplinary perspective that involves many layers
of the society.
Trafficking in human beings is an abhorrent phenomenon highly
affecting negatively the victims and their families in both human and
material aspect, sometimes causing irreversible damages. The longer
term effects of this phenomenon, in countries with a weak economic
development and extremely young and dynamic population, such as
Kosovo, without proper measures to prevented and control can cause
tremendous damages in the society. Given the fact that a complete
eradication of this phenomenon is almost impossible, efforts should
be concentrated at least on the prevention and controlling aspects.
Treating trafficking in human beings based on traditional police
tactics, methods and proceedings cannot bring satisfactory results.
There is no doubt that a multi-disciplinary approach is an
irreplaceable requirement, in other words, a combination of authentic
and functional proactive and reactive methods, techniques and tactics.
Obviously, police must exercise its role in preventing and combating
trafficking in human beings, a role sanctioned by the law, however,
police role and contribution cannot by any means considered
complete if all segments of the society are not included in these
efforts. Naturally, civil society should have an important share in
these collaborative and interactive efforts especially in preventive
activities such as: awareness on trafficking risks and damages,
proactive engagement in drafting appropriate legislation and
strategies, law enforcement monitoring and direct or indirect
involvement in protective and supporting activities which benefit the
victims of trafficking etc.
Abstract: Removal of the widespread used drug paracetamol
from water was investigated using activated carbon originated from
dende coconut mesocarp and babassu coconut mesocarp. Kinetic and
equilibrium data were obtained at different values of pH. Both
activated carbons showed high efficiency when pH ≤ pHPZC as the
carbonil group of paracetamol molecule are adsorbed due to
positively charged carbon surface. Microporosity also played an
important role in such process. Pseudo-second order model was better
adjusted to the kinetic results. Equilibrium data may be represented
by Langmuir equation.
Abstract: Heat transfer due to forced convection of copper water
based nanofluid has been predicted by Artificial Neural network
(ANN). The present nanofluid is formed by mixing copper
nanoparticles in water and the volume fractions are considered here
are 0% to 15% and the Reynolds number are kept constant at 100.
The back propagation algorithm is used to train the network. The
present ANN is trained by the input and output data which has been
obtained from the numerical simulation, performed in finite volume
based Computational Fluid Dynamics (CFD) commercial software
Ansys Fluent. The numerical simulation based results are compared
with the back propagation based ANN results. It is found that the
forced convection heat transfer of water based nanofluid can be
predicted correctly by ANN. It is also observed that the back
propagation ANN can predict the heat transfer characteristics of
nanofluid very quickly compared to standard CFD method.