Abstract: The reduction of phosphorus and sulfur in engine oil
are the main topics of this paper. Very reproducible boundary
lubrication tests were conducted as part of Design of Experiment
software (DOE) to study the behavior of fluorinated catalyst iron
fluoride (FeF3), and polutetrafluoroethylene or Teflon (PTFE) in
developing environmentally friendly (reduced P and S) anti-wear
additives for future engine oil formulations. Multi-component
Chevron fully formulated oil (GF3) and Chevron plain oil were used
with the addition of PTFE and catalyst to characterize and analyze
their performance. Lower phosphorus blends were the goal of the
model solution. Experiments indicated that new sub-micron FeF3
catalyst played an important role in preventing breakdown of the
tribofilm.
Abstract: In this study, one dimensional phase change problem
(a Stefan problem) is considered and a numerical solution of this
problem is discussed. First, we use similarity transformation to
convert the governing equations into ordinary differential equations
with its boundary conditions. The solutions of ordinary differential
equation with the associated boundary conditions and interface
condition (Stefan condition) are obtained by using a numerical
approach based on operational matrix of differentiation of shifted
second kind Chebyshev wavelets. The obtained results are compared
with existing exact solution which is sufficiently accurate.
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: There have been rigorous research and development
of unmanned aerial vehicles in the field of search and rescue (SAR)
operation recently. UAVs reduce unnecessary human risks while
assisting rescue efforts through aerial imagery, topographic mapping
and emergency delivery. The application of UAVs in offshore and
nearshore marine SAR missions is discussed in this paper. Projects
that integrate UAV technology into their systems are introduced to
highlight the great advantages and capabilities of UAVs. Scenarios
where UAVs could provide invaluable assistance are also suggested.
Abstract: Si ion implantation was widely used to synthesize
specimens of SiO2 containing supersaturated Si and subsequent high
temperature annealing induces the formation of embedded
luminescent Si nanocrystals. In this work, the potentialities of excimer
UV-light (172 nm, 7.2 eV) irradiation and rapid thermal annealing
(RTA) to enhance the photoluminescence and to achieve low
temperature formation of Si nanocrystals have been investigated. The
Si ions were introduced at acceleration energy of 180 keV to fluence of
7.5 x 1016 ions/cm2. The implanted samples were subsequently
irradiated with an excimer-UV lamp. After the process, the samples
were rapidly thermal annealed before furnace annealing (FA).
Photoluminescence spectra were measured at various stages at the
process. We found that the luminescence intensity is strongly
enhanced with excimer-UV irradiation and RTA. Moreover, effective
visible photoluminescence is found to be observed even after FA at
900 oC, only for specimens treated with excimer-UV lamp and RTA.
We also prepared specimens of Si nanocrystals embedded in a SiO2 by
reactive pulsed laser deposition (PLD) in an oxygen atmosphere. We
will make clear the similarities and differences with the way of
preparation.
Abstract: An Acoustic Micro-Energy Harvester (AMEH) is
developed to convert wasted acoustical energy into useful electrical
energy. AMEH is mathematically modeled using Lumped Element
Modelling (LEM) and Euler-Bernoulli beam (EBB) modelling. An
experiment is designed to validate the mathematical model and assess
the feasibility of AMEH. Comparison of theoretical and experimental
data on critical parameter value such as Mm, Cms, dm and Ceb showed
the variances are within 1% to 6%, which is reasonably acceptable.
Then, AMEH undergoes bandwidth tuning for performance
optimization. The AMEH successfully produces 0.9V/(m/s^2) and
1.79μW/(m^2/s^4) at 60Hz and 400kΩ resistive load which only
show variances about 7% compared to theoretical data. At 1g and
60Hz resonance frequency, the averaged power output is about
2.2mW which fulfilled a range of wireless sensors and
communication peripherals power requirements. Finally, the design
for AMEH is assessed, validated and deemed as a feasible design.
Abstract: This study investigates the effects of the lead angle
and chip thickness variation on surface roughness during the
machining of compacted graphite iron using ceramic cutting tools
under dry cutting conditions. Analytical models were developed for
predicting the surface roughness values of the specimens after the
face milling process. Experimental data was collected and imported
to the artificial neural network model. A multilayer perceptron model
was used with the back propagation algorithm employing the input
parameters of lead angle, cutting speed and feed rate in connection
with chip thickness. Furthermore, analysis of variance was employed
to determine the effects of the cutting parameters on surface
roughness. Artificial neural network and regression analysis were
used to predict surface roughness. The values thus predicted were
compared with the collected experimental data, and the
corresponding percentage error was computed. Analysis results
revealed that the lead angle is the dominant factor affecting surface
roughness. Experimental results indicated an improvement in the
surface roughness value with decreasing lead angle value from 88° to
45°.
Abstract: Based on Business and Consumer Survey (BCS) data,
the European Commission (EC) regularly publishes the monthly
Economic Sentiment Indicator (ESI) for each EU member state. ESI
is conceptualized as a leading indicator, aimed ad tracking the overall
economic activity. In calculating ESI, the EC employs arbitrarily
chosen weights on 15 BCS response balances. This paper raises the
predictive quality of ESI by applying nonlinear programming to find
such weights that maximize the correlation coefficient of ESI and
year-on-year GDP growth. The obtained results show that the highest
weights are assigned to the response balances of industrial sector
questions, followed by questions from the retail trade sector. This
comes as no surprise since the existing literature shows that the
industrial production is a plausible proxy for the overall Croatian
economic activity and since Croatian GDP is largely influenced by
the aggregate personal consumption.
Abstract: Elastomeric polymer foam has been used widely in
the automotive industry, especially for isolating unwanted vibrations.
Such material is able to absorb unwanted vibration due to its
combination of elastic and viscous properties. However, the ‘creep
effect’, poor stress distribution and susceptibility to high
temperatures are the main disadvantages of such a system.
In this study, improvements in the performance of elastomeric
foam as a vibration isolator were investigated using the concept of
Foam Filled Fluid (FFFluid). In FFFluid devices, the foam takes the
form of capsule shapes, and is mixed with viscous fluid, while the
mixture is contained in a closed vessel. When the FFFluid isolator is
affected by vibrations, energy is absorbed, due to the elastic strain of
the foam. As the foam is compressed, there is also movement of the
fluid, which contributes to further energy absorption as the fluid
shears. Also, and dependent on the design adopted, the packaging
could also attenuate vibration through energy absorption via friction
and/or elastic strain.
The present study focuses on the advantages of the FFFluid
concept over the dry polymeric foam in the role of vibration isolation.
This comparative study between the performance of dry foam and the
FFFluid was made according to experimental procedures. The paper
concludes by evaluating the performance of the FFFluid isolator in
the suspension system of a light vehicle. One outcome of this
research is that the FFFluid may preferable over elastomer isolators
in certain applications, as it enables a reduction in the effects of high
temperatures and of ‘creep effects’, thereby increasing the reliability
and load distribution. The stiffness coefficient of the system has
increased about 60% by using an FFFluid sample. The technology
represented by the FFFluid is therefore considered by this research
suitable for application in the suspension system of a light vehicle.
Abstract: The literature on language teaching and second
language acquisition has been largely driven by monolingual
ideology with a common assumption that a second language (L2) is
best taught and learned in the L2 only. The current study challenges
this assumption by reporting learners' positive perceptions of tertiary
level teachers' code switching practices in Vietnam. The findings of
this study contribute to our understanding of code switching practices
in language classrooms from a learners' perspective.
Data were collected from student participants who were working
towards a Bachelor degree in English within the English for Business
Communication stream through the use of focus group interviews.
The literature has documented that this method of interviewing has a
number of distinct advantages over individual student interviews. For
instance, group interactions generated by focus groups create a more
natural environment than that of an individual interview because they
include a range of communicative processes in which each individual
may influence or be influenced by others - as they are in their real
life. The process of interaction provides the opportunity to obtain the
meanings and answers to a problem that are "socially constructed
rather than individually created" leading to the capture of real-life
data. The distinct feature of group interaction offered by this
technique makes it a powerful means of obtaining deeper and richer
data than those from individual interviews. The data generated
through this study were analysed using a constant comparative
approach. Overall, the students expressed positive views of this
practice indicating that it is a useful teaching strategy. Teacher code
switching was seen as a learning resource and a source supporting
language output. This practice was perceived to promote student
comprehension and to aid the learning of content and target language
knowledge. This practice was also believed to scaffold the students'
language production in different contexts. However, the students
indicated their preference for teacher code switching to be
constrained, as extensive use was believed to negatively impact on
their L2 learning and trigger cognitive reliance on the L1 for L2
learning. The students also perceived that when the L1 was used to a
great extent, their ability to develop as autonomous learners was
negatively impacted.
This study found that teacher code switching was supported in
certain contexts by learners, thus suggesting that there is a need for
the widespread assumption about the monolingual teaching approach
to be re-considered.
Abstract: Food poisoning and infection by bacteria are of public
health significance to both developing and developed countries.
Samples of ogi (akamu) prepared from white and yellow variety of
maize sold in Uturu and Okigwe were analyzed together with the
laboratory prepared ogi for bacterial quality using the standard
microbiological methods. The analyses showed that both white and
yellow variety had total bacterial counts (cfu/g) of 4.0 ×107 and 3.9 x
107 for the laboratory prepared ogi while the commercial ogi had 5.2
x 107 and 4.9 x107, 4.9 x107 and 4.5 x107, 5.4 x107 and 5.0 x107 for
Eke-Okigwe, Up-gate and Nkwo-Achara market respectively. The
Staphylococcal counts ranged from 2.0 x 102 to 5.0 x102 and 1.0 x
102 to 4.0 x102 for the white and yellow variety from the different
markets while Staphylococcal growth was not recorded on the
laboratory prepared ogi. The laboratory prepared ogi had no Coliform
growth while the commercially prepared ogi had counts of 0.5 x103
to 1.6 x 103 for white variety and 0.3 x 103 to 1.1 x103 for yellow
variety respectively. The Lactic acid bacterial count of 3.5x106 and
3.0x106 was recorded for the laboratory ogi while the commercially
prepared ogi ranged from 3.2x106 to 4.2x106 (white variety) and 3.0
x106 to 3.9 x106 (yellow). The presence of bacteria isolates from the
commercial and laboratory fermented ogi showed that Lactobacillus
sp, Leuconostoc sp and Citrobacter sp were present in all the
samples, Micrococcus sp and Klebsiella sp were isolated from Eke-
Okigwe and ABSU-up-gate markets varieties respectively, E. coli
and Staphylococcus sp were present in Eke-Okigwe and Nkwo-
Achara markets while Salmonella sp were isolated from the three
markets. Hence, there are chances of contracting food borne diseases
from commercially prepared ogi. Therefore, there is the need for
sanitary measures in the production of fermented cereals so as to
minimize the rate of food borne pathogens during processing and
storage.
Abstract: Waste Load Allocation (WLA) strategies usually
intend to find economic policies for water resource management.
Water quality trading (WQT) is an approach that uses discharge
permit market to reduce total environmental protection costs. This
primarily requires assigning discharge limits known as total
maximum daily loads (TMDLs). These are determined by monitoring
organizations with respect to the receiving water quality and
remediation capabilities. The purpose of this study is to compare two
approaches of TMDL assignment for WQT policy in small catchment
area of Haraz River, in north of Iran. At first, TMDLs are assigned
uniformly for the whole point sources to keep the concentrations of
BOD and dissolved oxygen (DO) at the standard level at checkpoint
(terminus point). This was simply simulated and controlled by
Qual2kw software. In the second scenario, TMDLs are assigned
using multi objective particle swarm optimization (MOPSO) method
in which the environmental violation at river basin and total treatment
costs are minimized simultaneously. In both scenarios, the equity
index and the WLA based on trading discharge permits (TDP) are
calculated. The comparative results showed that using economically
optimized TMDLs (2nd scenario) has slightly more cost savings rather
than uniform TMDL approach (1st scenario). The former annually
costs about 1 M$ while the latter is 1.15 M$. WQT can decrease
these annual costs to 0.9 and 1.1 M$, respectively. In other word,
these approaches may save 35 and 45% economically in comparison
with command and control policy. It means that using multi objective
decision support systems (DSS) may find more economical WLA,
however its outcome is not necessarily significant in comparison with
uniform TMDLs. This may be due to the similar impact factors of
dischargers in small catchments. Conversely, using uniform TMDLs
for WQT brings more equity that makes stakeholders not feel that
much envious of difference between TMDL and WQT allocation. In
addition, for this case, determination of TMDLs uniformly would be
much easier for monitoring. Consequently, uniform TMDL for TDP
market is recommended as a sustainable approach. However,
economical TMDLs can be used for larger watersheds.
Abstract: Due to the resultant leachate from waste
decomposition in landfills has polluter potential hundred times
greater than domestic sewage, this is considered a problem related to
the depreciation of environment requiring pre-disposal treatment.In
seeking to improve this situation, this project proposes the treatment
of landfill leachate using natural fibers intercropped with advanced
oxidation processes. The selected natural fibers were palm, coconut
and banana fiber.These materials give sustainability to the project
because, besides having adsorbent capacity, are often part of waste
discarded. The study was conducted in laboratory scale.In trials, the
effluents were characterized as Chemical Oxygen Demand (COD),
Turbidity and Color. The results indicate that is technically
promising since that there were extremely oxidative conditions, the
use of certain natural fibers in the reduction of pollutants in leachate
have been obtained results of COD removals between 67.9% and
90.9%, Turbidity between 88.0% and 99.7% and Color between
67.4% and 90.4%.The expectation generated is to continue evaluating
the association of efficiency of other natural fibers with other landfill
leachate treatment processes.
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: In this study, the feasibility of incorporating ceramic
waste from bricks (perforated brick and double hollow brick) and
extruded polystyrene (XPS) waste, is analysed.
Results show that it is possible to incorporate up to 25% of
ceramic waste and 4% of XPS waste over the weight of gypsum in a
gypsum matrix. Furthermore, with the addition of ceramic waste an
8% of surface hardness increase and a 25% of capillary water
absorption reduction can be obtained. On the other hand, with the
addition of XPS, a 26% reduction of density and a 37% improvement
of thermal conductivity can be obtained.
The obtained results are favorable to use these materials in order to
produce prefabricated gypsum and also as material for interior
cladding walls.
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: Several parameters are established in order to measure
biodiesel quality. One of them is the iodine value, which is an
important parameter that measures the total unsaturation within a
mixture of fatty acids. Limitation of unsaturated fatty acids is
necessary since warming of higher quantity of these ones ends in
either formation of deposits inside the motor or damage of lubricant.
Determination of iodine value by official procedure tends to be very
laborious, with high costs and toxicity of the reagents, this study uses
artificial neural network (ANN) in order to predict the iodine value
property as an alternative to these problems. The methodology of
development of networks used 13 esters of fatty acids in the input
with convergence algorithms of back propagation of back
propagation type were optimized in order to get an architecture of
prediction of iodine value. This study allowed us to demonstrate the
neural networks’ ability to learn the correlation between biodiesel
quality properties, in this caseiodine value, and the molecular
structures that make it up. The model developed in the study reached
a correlation coefficient (R) of 0.99 for both network validation and
network simulation, with Levenberg-Maquardt algorithm.
Abstract: A comparison of activity and stability of the as-formed
Pt/C, Pt-Co and Pt-Pd/C electrocatalysts, prepared by a combined
approach of impregnation and seeding, was performed. According to
the activity test in a single Proton Exchange Membrane (PEM) fuel
cell, the Oxygen Reduction Reaction (ORR) activity of the Pt-M/C
electrocatalyst was slightly lower than that of Pt/C. The j0.9 V and
E10 mA/cm2 of the as-prepared electrocatalysts increased in the order of
Pt/C > Pt-Co/C > Pt-Pd/C. However, in the medium-to-high current
density region, Pt-Pd/C exhibited the best performance. With regard to
their stability in a 0.5 M H2SO4 electrolyte solution, the
electrochemical surface area decreased as the number of rounds of
repetitive potential cycling increased due to the dissolution of the
metals within the catalyst structure. For long-term measurement, Pt-
Pd/C was the most stable than the other three electrocatalysts.
Abstract: This work studies the effect of chemical composition
on the activity and selectivity of γ–alumina supported CuO/
MnO2/Cr2O3 catalysts toward deep oxidation of CO, dimethyl ether
(DME) and methanol. The catalysts were prepared by impregnation
of the support with an aqueous solution of copper nitrate, manganese
nitrate and CrO3 under different conditions. Thermal, XRD and TPR
analysis were performed. The catalytic measurements of single
compounds oxidation were carried out on continuous flow equipment
with a four-channel isothermal stainless steel reactor. Flow-line
equipment with an adiabatic reactor for simultaneous oxidation of all
compounds under the conditions that mimic closely the industrial
ones was used. The reactant and product gases were analyzed by
means of on-line gas chromatographs.
On the basis of XRD analysis it can be concluded that the active
component of the mixed Cu-Mn-Cr/γ–alumina catalysts consists of at
least six compounds – CuO, Cr2O3, MnO2, Cu1.5Mn1.5O4,
Cu1.5Cr1.5O4 and CuCr2O4, depending on the Cu/Mn/Cr molar ratio.
Chemical composition strongly influences catalytic properties, this
influence being quite variable with regards to the different processes.
The rate of CO oxidation rapidly decrease with increasing of
chromium content in the active component while for the DME was
observed the reverse trend. It was concluded that the best
compromise are the catalysts with Cu/(Mn + Cr) molar ratio 1:5 and
Mn/Cr molar ratio from 1:3 to 1:4.
Abstract: Currently, continuous two-phase decanter process
used for olive oil production is the more internationally widespread.
The wastewaters generated from this industry (OMW) are a real
environmental problem because of its high organic load. Among
proposed treatments for these wastewaters, advanced oxidation
technologies (Fenton, ozone, photoFenton, etc.) are the most
favourable. The direct application of these processes is somewhat
expensive. Therefore, the application of a previous stage based on a
flocculation-sedimentation operation is of high importance. In this
research five commercial flocculants (three cationic, and two anionic)
have been used to achieve the separation of phases (liquid clarifiedsludge).
For each flocculant, different concentrations (0-1000 mg/L)
have been studied. In these experiments, sludge volume formed and
the final water quality were determined. The final removal
percentages of total phenols (11.3-25.1%), COD (5.6-20.4%), total
carbon (2.3-26.5%), total organic carbon (1.50-23.8%), total nitrogen
(1.45-24.8%), and turbidity (27.9-61.4%) were determined. The
variation on electric conductivity reduction percentage (1-8%) was
also determined. Finally, the best flocculants with highest removal
percentages have been determined (QG2001 and Flocudex CS49).