Abstract: In the present study, M2 high speed steels were
fabricated by using electro-slag rapid remelting process. Carbide
structure was analysed and the fracture toughness and hardness were
also measured after austenitization treatment at 1190 and 1210oC
followed by tempering treatment at 535oC for billets with various
diameters from 16 to 60 mm. Electro-slag rapid remelting (ESRR)
process is an advanced ESR process combined by continuous casting
and successfully employed in this study to fabricate a sound M2 high
speed ingot. Three other kinds of commercial M2 high speed steels,
produced by traditional method, were also analysed for comparison.
Distribution and structure of eutectic carbides of the ESRR billet were
found to be comparable to those of commercial alloy and so was the
fracture toughness.
Abstract: Phase equilibria of AZ91D Mg alloys for
nonflammable use, containing Ca and Y, were carried out by using
FactSage® and FTLite database, which revealed that solid solution
treatment could be performed at temperatures from 400 to 450oC.
Solid solution treatment of AZ91D Mg alloy without Ca and Y was
successfully conducted at 420oC and supersaturated microstructure
with all beta phase resolved into matrix was obtained. In the case of
AZ91D Mg alloy with some Ca and Y; however, a little amount of
intermetallic particles were observed after solid solution treatment.
After solid solution treatment, each alloy was annealed at temperatures
of 180 and 200oC for time intervals from 1 min to 48 hrs and hardness
of each condition was measured by micro-Vickers method. Peak aging
conditions were deduced as at the temperature of 200oC for 10 hrs.
Abstract: The ever increasing amount of solid waste (SW)
generated which is exacerbated by lack of proper waste management
system is of growing concern worldwide and in major cities in
developing countries due to its social, economic and environmental
implications. This study attempts to describe the aspects of solid
waste management (SWM) in Adama, one of the fast urbanizing
cities in Ethiopia, and highlights the challenges thereof. Data were
gathered through interview supplemented by field observation and
self-administered questionnaire. Then, the data were analyzed using
the Statistical Package for Social Science (SPSS) software. In
addition, secondary data were gathered from documents. Findings
revealed that the current SWM practice couldn’t cope with the fast
urbanizing needs and the rapid population growth exhibited by the
city. Besides, major factors contributing to the inefficient system
were identified. The study would provide practical insights to
decision makers in developing a sustainable SWM system leading to
minimized risk in the city.
Abstract: Multipotent mesenchymal stromal cells (MSCs)
possess immunomodulatory properties. The effect of MSCs on the
crucial cellular immunity compartment – T-cells is of a special
interest. It is known that MSC tissue niche and expected milieu of
their interaction with T- cells are characterized by low oxygen
concentration, whereas the in vitro experiments usually are carried
out at a much higher ambient oxygen (20%). We firstly evaluated
immunomodulatory effects of MSCs on T-cells at tissue-related
oxygen (5%) after interaction implied cell-to-cell contacts and
paracrine factors only. It turned out that MSCs under reduced oxygen
can effectively suppress the activation and proliferation of PHAstimulated
T-cells and can provoke decrease in the production of
proinflammatory and increase in anti-inflammatory cytokines. In
hypoxia some effects were amplified (inhibition of proliferation, antiinflammatory
cytokine profile shift). This impact was more evident
after direct cell-to-cell interaction; lack of intercellular contacts could
revoke the potentiating effect of hypoxia.
Abstract: This paper presents the variation of the dynamic
characteristics of a spindle with the change of bearing preload. The
correlations between the variation of bearing preload and fundamental
modal parameters were first examined by conducting vibration tests on
physical spindle units. Experimental measurements show that the
dynamic compliance and damping ratio associated with the
dominating modes were affected to vary with variation of the bearing
preload. When the bearing preload was slightly deviated from a
standard value, the modal frequency and damping ability also vary to
different extent, which further enable the spindle to perform with
different compliance. For the spindle used in this study, a standard
preload value set on bearings would enable the spindle to behave a
higher stiffness as compared with others with a preload variation. This
characteristic can be served as a reference to examine the variation of
bearing preload of spindle in assemblage or operation.
Abstract: The purposes of this study were to design and find
users’ satisfaction after using the decision support system for tourism
northern part of Thailand, which can provide tourists touristic
information and plan their personal voyage. Such information can be
retrieved systematically based on personal budget and provinces. The
samples of this study were five experts and users 30 persons white
collars in Bangkok. This decision support system was designed via
ASP.NET. Its database was developed by using MySQL, for
administrators are able to effectively manage the database. The
application outcome revealed that the innovation works properly as
sought in objectives. Specialists and white collars in Bangkok have
evaluated the decision support system; the result was satisfactorily
positive.
Abstract: Most flexible rotors can be considered as beam-like
structures. In many cases, rotors are modeled as one-dimensional
bodies, made basically of beam-like shafts with rigid bodies attached
to them. This approach is typical of rotor dynamics, both analytical
and numerical, and several rotor dynamic codes, based on the finite
element method, follow this trend. In this paper, a finite element
model based on Timoshenko beam elements is utilized to analyze the
lateral dynamic behavior of a certain rotor-bearing system in
operating conditions.
Abstract: Analysis of real life problems often results in linear
systems of equations for which solutions are sought. The method to
employ depends, to some extent, on the properties of the coefficient
matrix. It is not always feasible to solve linear systems of equations
by direct methods, as such the need to use an iterative method
becomes imperative. Before an iterative method can be employed
to solve a linear system of equations there must be a guaranty that
the process of solution will converge. This guaranty, which must
be determined apriori, involve the use of some criterion expressible
in terms of the entries of the coefficient matrix. It is, therefore,
logical that the convergence criterion should depend implicitly on the
algebraic structure of such a method. However, in deference to this
view is the practice of conducting convergence analysis for Gauss-
Seidel iteration on a criterion formulated based on the algebraic
structure of Jacobi iteration. To remedy this anomaly, the Gauss-
Seidel iteration was studied for its algebraic structure and contrary
to the usual assumption, it was discovered that some property of the
iteration matrix of Gauss-Seidel method is only diagonally dominant
in its first row while the other rows do not satisfy diagonal dominance.
With the aid of this structure we herein fashion out an improved
version of Gauss-Seidel iteration with the prospect of enhancing
convergence and robustness of the method. A numerical section is
included to demonstrate the validity of the theoretical results obtained
for the improved Gauss-Seidel method.
Abstract: The emergence of the Semantic Web technology
increases day by day due to the rapid growth of multiple web pages.
Many standard formats are available to store the semantic web data.
The most popular format is the Resource Description Framework
(RDF). Querying large RDF graphs becomes a tedious procedure
with a vast increase in the amount of data. The problem of query
optimization becomes an issue in querying large RDF graphs.
Choosing the best query plan reduces the amount of query execution
time. To address this problem, nature inspired algorithms can be used
as an alternative to the traditional query optimization techniques. In
this research, the optimal query plan is generated by the proposed
SAPSO algorithm which is a hybrid of Simulated Annealing (SA)
and Particle Swarm Optimization (PSO) algorithms. The proposed
SAPSO algorithm has the ability to find the local optimistic result
and it avoids the problem of local minimum. Experiments were
performed on different datasets by changing the number of predicates
and the amount of data. The proposed algorithm gives improved
results compared to existing algorithms in terms of query execution
time.
Abstract: This study aims to examine the role of career
advancement and job security as predictors of employee commitment
to their organization. Data was collected from 580 frontline
employees attached to two departments of 29 luxury hotels in
Peninsular Malaysia. Statistical results using Partial Least Squares
technique provided support for the proposed hypotheses. In view of
the findings, theoretical and practical implications are discussed.
Abstract: High temperature deformation behavior of cast
Fe-20Cr-5Al alloy has been investigated in this study by performing
tensile and compression tests at temperatures from 1100 to 1200oC.
Rectangular ingots of which the dimensions were 300×300×100 in
millimeter were cast using vacuum induction melting. Phase
equilibrium was calculated using the FactSage®, thermodynamic
software and database. Tensile strength of cast Fe-20Cr-5Al alloy was
4 MPa at 1200oC. With temperature decreased, tensile strength
increased rapidly and reached up to 13 MPa at 1100oC. Elongation
also increased from 18 to 80% with temperature decreased from
1200oC to 1100oC. Microstructure observation revealed that M23C6
carbide was precipitated along the grain boundary and within the
matrix.
Abstract: This paper proposes a cooperative Alamouti space time
transmission scheme with low relay complexity for the cooperative
communication systems. In the proposed scheme, the source node
combines the data symbols to construct the Alamouti-coded form at
the destination node, while the conventional scheme performs the
corresponding operations at the relay nodes. In simulation results,
it is shown that the proposed scheme achieves the second order
cooperative diversity while maintaining the same bit error rate (BER)
performance as that of the conventional scheme.
Abstract: This paper analyzes innovation trends in South Korea
by means of the number of patent applications filed by residents and
nonresidents during the period 1965 to 2012. Making use of patent
data released by the World Intellectual Property Organization
(WIPO), we search for the presence of multiple structural changes in
patent application series in this country. These changes may suggest
that firms’ innovative activity has been modified as a result of
implementing some science, technology and innovation (STI)
policies. Accordingly, the new regulations implemented in this
country in the last decades have influenced its innovative activity.
The question conducting this research is thus how STI policies in
South Korea have influenced its innovation activity. The results
confirm the existence of multiple structural changes in the series of
patent applications resulting from alternative STI policies
implemented during these years.
Abstract: Bureaucracy reform program drives Indonesian
government to change their management to enhance their
organizational performance. Information technology became one of
strategic plan that organization tried to improve. Knowledge
management system is one of information system that supporting
knowledge management implementation in government which
categorized as people perspective, because this system has high
dependency in human interaction and participation. Strategic plan for
developing knowledge management system can be determine using
some of information system strategic methods. This research
conducted to define type of strategic method of information system,
stage of activity each method, strength and weakness. Literature
review methods used to identify and classify strategic methods of
information system, differentiate method type, categorize common
activities, strength and weakness. Result of this research are
determine and compare six strategic information system methods,
Balanced Scorecard and Risk Analysis believe as common strategic
method that usually used and have the highest excellence strength.
Abstract: This paper presents the application of finite dynamic
programming, specifically the "Markov Chain" model, as part of the
decision making process of a company in the cosmetics sector located
in the vicinity of Bogota DC. The objective of this process was to
decide whether the company should completely reconstruct its
wastewater treatment plant or instead optimize the plant through the
addition of equipment. The goal of both of these options was to make
the required improvements in order to comply with parameters
established by national legislation regarding the treatment of waste
before it is released into the environment. This technique will allow
the company to select the best option and implement a solution for
the processing of waste to minimize environmental damage and the
acquisition and implementation costs.
Abstract: ‘Steganalysis’ is one of the challenging and attractive interests for the researchers with the development of information hiding techniques. It is the procedure to detect the hidden information from the stego created by known steganographic algorithm. In this paper, a novel feature based image steganalysis technique is proposed. Various statistical moments have been used along with some similarity metric. The proposed steganalysis technique has been designed based on transformation in four wavelet domains, which include Haar, Daubechies, Symlets and Biorthogonal. Each domain is being subjected to various classifiers, namely K-nearest-neighbor, K* Classifier, Locally weighted learning, Naive Bayes classifier, Neural networks, Decision trees and Support vector machines. The experiments are performed on a large set of pictures which are available freely in image database. The system also predicts the different message length definitions.
Abstract: Because of high thermal efficiency and low CO2
emission, diesel engines are being used widely in many industrial
fields although it makes many PM and NOx which give both human
health and environment a negative effect. NOx regulations for diesel
engines, however, are being strengthened and it is impossible to meet
the emission standard without NOx reduction devices such as SCR
(Selective Catalytic Reduction), LNC (Lean NOx Catalyst), and LNT
(Lean NOx Trap). Among the NOx reduction devices, urea-SCR
system is known as the most stable and efficient method to solve the
problem of NOx emission. But this device has some issues associated
with the ammonia slip phenomenon which is occurred by shortage of
evaporation and thermolysis time, and that makes it difficult to achieve
uniform distribution of the injected urea in front of monolith.
Therefore, this study has focused on the mixing enhancement between
urea and exhaust gases to enhance the efficiency of the SCR catalyst
equipped in catalytic muffler by changing inlet gas temperature and
spray conditions to improve the spray uniformity of the urea water
solution. Finally, it can be found that various parameters such as inlet
gas temperature and injector and injection angles significantly affect
the evaporation and mixing of the urea water solution with exhaust
gases, and therefore, optimization of these parameters are required.
Abstract: Recently GPS data is used in a lot of studies to
automatically reconstruct travel patterns for trip survey. The aim is to
minimize the use of questionnaire surveys and travel diaries so as to
reduce their negative effects. In this paper data acquired from GPS and
accelerometer embedded in smart phones is utilized to predict the
mode of transportation used by the phone carrier. For prediction,
Support Vector Machine (SVM) and Adaptive boosting (AdaBoost)
are employed. Moreover a unique method to improve the prediction
results from these algorithms is also proposed. Results suggest that the
prediction accuracy of AdaBoost after improvement is relatively better
than the rest.
Abstract: We have studied a method to widen the spectrum
of optical pulses that pass through an InGaAsP waveguide for
application to broadband optical communication. In particular, we
have investigated the competitive effect between spectral broadening
arising from nonlinear refraction (optical Kerr effect) and shrinking
due to two photon absorption in the InGaAsP waveguide with
χ(3) nonlinearity. The shrunk spectrum recovers broadening by
the enhancement effect of the nonlinear refractive index near the
bandgap of InGaAsP with a bandgap wavelength of 1490 nm. The
broadened spectral width at around 1525 nm (196.7 THz) becomes
10.7 times wider than that at around 1560 nm (192.3 THz) without
the enhancement effect, where amplified optical pulses with a pulse
width of ∼ 2 ps and a peak power of 10 W propagate through a
1-cm-long InGaAsP waveguide with a cross-section of 4 (μm)2.
Abstract: Artificial Neural Networks (ANN) trained using backpropagation
(BP) algorithm are commonly used for modeling
material behavior associated with non-linear, complex or unknown
interactions among the material constituents. Despite multidisciplinary
applications of back-propagation neural networks
(BPNN), the BP algorithm possesses the inherent drawback of
getting trapped in local minima and slowly converging to a global
optimum. The paper present a hybrid artificial neural networks and
genetic algorithm approach for modeling slump of ready mix
concrete based on its design mix constituents. Genetic algorithms
(GA) global search is employed for evolving the initial weights and
biases for training of neural networks, which are further fine tuned
using the BP algorithm. The study showed that, hybrid ANN-GA
model provided consistent predictions in comparison to commonly
used BPNN model. In comparison to BPNN model, the hybrid ANNGA
model was able to reach the desired performance goal quickly.
Apart from the modeling slump of ready mix concrete, the synaptic
weights of neural networks were harnessed for analyzing the relative
importance of concrete design mix constituents on the slump value.
The sand and water constituents of the concrete design mix were
found to exhibit maximum importance on the concrete slump value.