Abstract: Protection of slope and embankment from erosion has
become an important issue in Bangladesh. The constructions of
strong structures require large capital, integrated designing, high
maintenance cost. Strong structure methods have negative impact on
the environment and sometimes not function for the design period.
Plantation of vetiver system along the slopes is an alternative
solution. Vetiver not only serves the purpose of slope protection but
also adds green environment reducing pollution. Vetiver is available
in almost all the districts of Bangladesh. This paper presents the
application of vetiver system with geo-jute, for slope protection and
erosion control of embankments and slopes. In-situ shear tests have
been conducted on vetiver rooted soil system to find the shear
strength. The shear strength and effective soil cohesion of vetiver
rooted soil matrix are respectively 2.0 times and 2.1 times higher than
that of the bared soil. Similar trends have been found in direct shear
tests conducted on laboratory reconstituted samples. Field trials have
been conducted in road embankment and slope protection with
vetiver at different sites. During the time of vetiver root growth the
soil protection has been accomplished by geo-jute. As the geo-jute
degrades with time, vetiver roots grow and take over the function of
geo-jutes. Slope stability analyses showed that vegetation increase
the factor of safety significantly.
Abstract: In contrast to conventional generators, self-excited induction generators are found to be most suitable machines for wind energy conversion in remote and windy areas due to many advantages over grid connected machines. This papers presents a Self-Excited Induction Generator (SEIG) driven by wind turbine and supplying an induction motor which is coupled to a centrifugal pump. A method to describe the steady state performance based on nodal analysis is presented. Therefore the advanced knowledge of the minimum excitation capacitor value is required. The effects of variation of excitation capacitance on system and rotor speed under different loading conditions have been analyzed and considered to optimize induction motor pump performances.
Abstract: The major focus of this work was to characterize hydrodynamics in a packed-bed with and without static mixer by using Computational Fluid Dynamic (CFD). The commercial software: COMSOL MULTIPHYSICSTM Version 3.3 was used to simulate flow fields of mixed-gas reactants i.e. CO and H2. The packed-bed was a single tube with the inside diameter of 0.8 cm and the length of 1.2 cm. The static mixer was inserted inside the tube. The number of twisting elements was 1 with 0.8 cm in diameter and 1.2 cm in length. The packed-bed with and without static mixer were both packed with approximately 700 spherical structures representing catalyst pellets. Incompressible Navier-Stokes equations were used to model the gas flow inside the beds at steady state condition, in which the inlet Reynolds Number (Re) was 2.31. The results revealed that, with the insertion of static mixer, the gas was forced to flow radially inward and outward between the central portion of the tube and the tube wall. This could help improving the overall performance of the packed-bed, which could be utilized for heterogeneous catalytic reaction such as reforming and Fischer- Tropsch reactions.
Abstract: The copper flotation tailings from Konkola Copper
mine in Nchanga, Zambia were used in the study. The purpose of this
study was to determine the leaching characteristics of the tailings
material prior and after the physical beneficiation process is
employed. The Knelson gravity concentrator (KC-MD3) was used for
the beneficiation process. The copper leaching efficiencies and
impurity co-extraction percentages in both the upgraded and the raw
feed material were determined at different pH levels and temperature.
It was observed that the copper extraction increased with an increase
in temperature and a decrease in pH levels. In comparison to the raw
feed sample, the upgraded sample reported a maximum copper
extraction of 69% which was 9%, higher than raw feed % extractions.
The impurity carry over was reduced from 18% to 4 % on the
upgraded sample. The reduction in impurity co-extraction was as a
result of the removal of the reactive gangue elements during the
upgrading process, this minimized the number of side reaction
occurring during leaching.
Abstract: In this paper, FinFET devices are analyzed with
emphasis on sub-threshold leakage current control. This is achieved
through proper biasing of the back gate, and through the use of
asymmetric work functions for the four terminal FinFET devices. We
are also examining different configurations of multiplexers and XOR
gates using transistors of symmetric and asymmetric work functions.
Based on extensive characterization data for MUX circuits, our
proposed configuration using symmetric devices lead to leakage
current and delay improvements of 65% and 47% respectively
compared to results in the literature. For XOR gates, a 90%
improvement in the average leakage current is achieved by using
asymmetric devices. All simulations are based on a 25nm FinFET
technology using the University of Florida UFDG model.
Abstract: In this paper, the effect of transmission codes on the
performance of coherent square M-ary quadrature amplitude
modulation (CSMQAM) under hybrid selection/maximal-ratio
combining (H-S/MRC) diversity is analysed. The fading channels are
modeled as frequency non-selective slow independent and identically
distributed Rayleigh fading channels corrupted by additive white
Gaussian noise (AWGN). The results for coded MQAM are
computed numerically for the case of (24,12) extended Golay code
and compared with uncoded MQAM under H-S/MRC diversity by
plotting error probabilities versus average signal to noise ratio (SNR)
for various values L and N in order to examine the improvement in
the performance of the digital communications system as the number
of selected diversity branches is increased. The results for no
diversity, conventional SC and Lth order MRC schemes are also
plotted for comparison. Closed form analytical results derived in this
paper are sufficiently simple and therefore can be computed
numerically without any approximations. The analytical results
presented in this paper are expected to provide useful information
needed for design and analysis of digital communication systems
over wireless fading channels.
Abstract: In the past 20 years the economy of the Czech
Republic has experienced substantial changes. In the 1990s the
development was affected by the transformation which sought to
establish the right conditions for privatization and creation of
elementary market relations. In the last decade the characteristic
elements such as private ownership and corresponding institutional
framework have been strengthened. This development was marked by
the accession of the Czech Republic to the EU. The Czech Republic
is striving to reduce the difference between its level of economic
development and the quality of institutional framework in
comparison with other developed countries. The process of finding
the adequate solutions has been hampered by the negative impact of
the world financial crisis on the Czech Republic and the standard of
living of its inhabitants. This contribution seeks to address the
question of whether and to which extent the economic development
of the transitive Czech economy is affected by the change in
behaviour of households and their tendency to consumption, i.e. in
the sense of reduction or increase in demand for goods and services.
It aims to verify whether the increasing trend of household
indebtedness and decreasing trend of saving pose a significant risk in
the Czech Republic. At a general level the analysis aims to contribute
to finding an answer to the question of whether the debt increase of
Czech households is connected to the risk of "eating through" the
borrowed money and whether Czech households risk falling into a
debt trap. In addition to household indebtedness risks in the Czech
Republic the analysis will focus on identification of specifics of the
transformation phase of the Czech economy in comparison with the
EU countries, or selected OECD countries.
Abstract: The number of the companies accepting RFID in Korea
has been increased continuously due to the domestic development of
information technology. The acceptance of RFID by companies in
Korea enabled them to do business with many global enterprises in a
much more efficient and effective way. According to a survey[33,
p76], many companies in Korea have used RFID for inventory or
distribution manages. But, the use of RFID in the companies in Korea
is in the early stages and its potential value hasn-t fully been realized
yet. At this time, it would be very important to investigate the factors
that affect RFID acceptance. For this study, many previous studies
were referenced and some RFID experts were interviewed. Through
the pilot test, four factors were selected - Security Trust, Employee
Knowledge, Partner Influence, Service Provider Trust - affecting
RFID acceptance and an extended technology acceptance
model(e-TAM) was presented with those factors. The proposed model
was empirically tested using data collected from employees in
companies or public enterprises. In order to analyze some
relationships between exogenous variables and four variables in TAM,
structural equation modeling(SEM) was developed and SPSS12.0 and
AMOS 7.0 were used for analyses. The results are summarized as
follows: 1) security trust perceived by employees positively
influences on perceived usefulness and perceived ease of use; 2)
employee-s knowledge on RFID positively influences on only
perceived ease of use; 3) a partner-s influence for RFID acceptance
positively influences on only perceived usefulness; 4) service provider
trust very positively influences on perceived usefulness and perceived
ease of use 5) the relationships between TAM variables are the same as
the previous studies.
Abstract: This paper presents a cold chain monitoring system which focuses on assessment of quality and dynamic pricing information about food in cold chain. Cold chain is composed of many actors and stages; however it can be seen as a single entity since a breakdown in temperature control at any stage can impact the final quality of the product. In a cold chain, the shelf life, quality, and safety of perishable food throughout the supply chain is greatly impacted by environmental factors especially temperature. In this paper, a prototype application is implemented to retrieve timetemperature history, the current quality and the dynamic price setting according to changing quality impacted by temperature fluctuations in real-time.
Abstract: In this study, hydrogels consisted of polyvinyl alcohol,
propylene glycol and β-glucan were developed by radiation technique
for wound dressing. The prepared hydrogels were characterized by
examining of physical properties such as gel fraction and absorption
ratio. The gel fraction and absorption ratio were dependent on the
crosslinking density. On observing the wound healing of rat skin, the
resulting hydrogels accelerated the wound healing comparing to cotton
gauze. Therefore, the PVA/propylene glycol/β-glucan blended
hydrogels can greatly accelerate the healing without causing irritation.
Abstract: This article investigated the validity of C-test and Cloze test which purport to measure general English proficiency. To provide empirical evidence pertaining to the validity of the interpretations based on the results of these integrative language tests, their criterion-related validity was investigated. In doing so, the test of English as a foreign language (TOEFL) which is an established, standardized, and internationally administered test of general English proficiency was used as the criterion measure. Some 90 Iranian English majors participated in this study. They were seniors studying English at a university in Tehran, Iran. The results of analyses showed that there is a statistically significant correlation among participants- scores on Cloze test, C-test, and the TOEFL. Building on the findings of the study and considering criterion-related validity as the evidential basis of the validity argument, it was cautiously deducted that these tests measure the same underlying trait. However, considering the limitations of using criterion measures to validate tests, no absolute claims can be made as to the construct validity of these integrative tests.
Abstract: According to the conception of personnel
management, human resource management requires efficient use of
human resources. This is ensured by various activities directed
towards the area of management. Among these activities there are for
example the recruitment of employees, development, strengthening
of relations, mutual inspiring, implementation of correct working
processes and systems used by individuals or groups.
Abstract: In this contribution, a way to enhance the performance of the classic Genetic Algorithm is proposed. The idea of restarting a Genetic Algorithm is applied in order to obtain better knowledge of the solution space of the problem. A new operator of 'insertion' is introduced so as to exploit (utilize) the information that has already been collected before the restarting procedure. Finally, numerical experiments comparing the performance of the classic Genetic Algorithm and the Genetic Algorithm with restartings, for some well known test functions, are given.
Abstract: The experimental thermal performance of two heat
exchangers in closed-wet cooling tower (CWCT) was investigated in
this study. The test sections are heat exchangers which have multi path
that is used as the entrance of cooling water and are consisting of
bare-type copper tubes between 15.88mm and 19.05mm. The process
fluids are the cooling water that flows from top part of heat exchanger
to bottom side in the inner side of tube, and spray water that flows
gravitational direction in the outer side of it. Air contacts its outer side
of that as it counterflows. Heat and mass transfer coefficients and
cooling capacity were calculated with variations of process fluids,
multi path and different diameter tubes to figure out the performance
of characteristics of CWCT.
The main results were summarized as follows: The results show this
experiment is reliable with values of heat and mass transfer
coefficients comparing to values of correlations. Heat and mass
transfer coefficients and cooling capacity of two paths are higher than
these with one path using 15.88 and 19.05mm tubes. Cooling capacity
per unit volume with 15.88mm tube using one and two paths are
higher than 19.05mm tube due to increase of surface area per unit
volume.
Abstract: School experiences, family bonding and self-concept
had always been a crucial factor in influencing all aspects of a
student-s development. The purpose of this study is to develop and to
validate a priori model of self-concept among students. The study
was tested empirically using Structural Equation Modeling (SEM)
and Confirmatory Factor Analysis (CFA) to validate the structural
model. To address these concerns, 1167 students were randomly
selected and utilized the Cognitive Psycho-Social University of
Malaya instrument (2009).Resulted demonstrated there is indirect
effect from family bonding to self-concept through school
experiences among secondary school students as a mediator. Besides
school experiences, there is a direct effect from family bonding to
self-concept and family bonding to school experiences among
students.
Abstract: The purposes of this research were to study the citizen
participation in preventing illegal drugs in one of a poor and small
community of Bangkok, Thailand and to compare the level of
participation and concern of illegal drugs problem by using
demographic variables. This paper drew upon data collected from a
local citizens survey conducted in Bangkok, Thailand during summer
of 2012. A total of 200 respondents were elicited as data input for,
and one way ANOVA test. The findings revealed that the overall
citizen participation was in the level of medium. The mean score
showed that benefit from the program was ranked as the highest and
the decision to participate was ranked as second while the follow-up
of the program was ranked as the lowest.
In terms of the difference in demographic such as gender, age,
level of education, income, and year of residency, the hypothesis
testing’s result disclosed that there were no difference in their level
of participation. However, difference in occupation showed a
difference in their level of participation and concern which was
significant at the 0.05 confidence level.
Abstract: Permeability reduction induced by asphaltene
precipitation during gas injection is one of the serious problems in
the oil industry. This problem can lead to formation damage and
decrease the oil production rate. In this work, Malaysian light oil
sample has been used to investigate the effect CO2 injection and
Water Alternating Gas (WAG) injection on permeability reduction.
In this work, dynamic core flooding experiments were conducted to
study the effect of CO2 and WAG injection on the amount of
asphaltene precipitated. Core properties after displacement were
inspected for any permeability reduction to study the effect of
asphaltene precipitation on rock properties.
The results showed that WAG injection gave less asphaltene
precipitation and formation damage compared to CO2 injection. The
study suggested that WAG injection can be one of the important
factors of managing asphaltene precipitation.
Abstract: We present a novel construction of 16-QAM codewords of length n = 2k . The number of constructed codewords is 162×[4k-1×k-k+1] . When these constructed codewords are utilized as a code in OFDM systems, their peak-to-mean envelope power ratios (PMEPR) are bounded above by 3.6 . The principle of our scheme is illustrated with a four subcarrier example.
Abstract: This paper reports on the enhanced photoluminescence
(PL) of nanocomposites through the layered structuring of phosphor
and quantum dot (QD). Green phosphor of Sr2SiO4:Eu, red QDs of
CdSe/CdS/CdZnS/ZnS core-multishell, and thermo-curable resin
were used for this study. Two kinds of composite (layered and mixed)
were prepared, and the schemes for optical energy transfer between
QD and phosphor were suggested and investigated based on PL decay
characteristics. It was found that the layered structure is more effective
than the mixed one in the respects of PL intensity, PL decay and
thermal loss. When this layered nanocomposite (QDs on phosphor) is
used to make white light emitting diode (LED), the brightness is
increased by 37 %, and the color rendering index (CRI) value is raised
to 88.4 compared to the mixed case of 80.4.
Abstract: One of the robust fault detection filter (RFDF)
designing method is based on sliding-mode theory. The main purpose
of our study is to introduce an innovative simplified reference
residual model generator to formulate the RFDF as a sliding-mode
observer without any manipulation package or transformation matrix,
through which the generated residual signals can be evaluated. So the
proposed design is more explicit and requires less design parameters
in comparison with approaches requiring changing coordinates. To
the best author's knowledge, this is the first time that the sliding
mode technique is applied to detect actuator and sensor faults in a
real boiler. The designing procedure is proposed in a drum boiler in
Synvendska Kraft AB Plant in Malmo, Sweden as a multivariable
and strongly coupled system. It is demonstrated that both sensor and
actuator faults can robustly be detected. Also sensor faults can be
diagnosed and isolated through this method.