Abstract: Polyurethanes (PURs) are very versatile polymeric
materials with a wide range of physical and chemical properties.
PURs have desirable properties such as high abrasion resistance, tear
strength, shock absorption, flexibility and elasticity. Although they
have relatively poor thermal stability, this can be improved by using
treated clay. Polyurethane/clay nanocomposites have been
synthesized from renewable sources. A polyol for the production of
polyurethane by reaction with an isocyanate was obtained by the
synthesis of palm oil-based oleic acid with glycerol. Dodecylbenzene
sulfonic acid (DBSA) was used as catalyst and emulsifier. The
unmodified clay (kunipia-F) was treated with cetyltrimethyl
ammonium bromide (CTAB-mont) and octadodecylamine (ODAmont).
The d-spacing in CTAB-mont and ODA-mont were 1.571 nm
and 1.798 nm respectively and larger than that of the pure-mont
(1.142 nm). The organoclay was completely intercalated in the
polyurethane, as confirmed by a wide angle x-ray diffraction
(WAXD) pattern.
The results showed that adding clay demonstrated better thermal
stability in comparison with the virgin polyurethane. Onset
degradation of pure PU is at 200oC, and is lower than that of the
CTAB-mont PU and ODA-mont PU which takes place at about
318oC and 330oC, respectively. The mechanical properties (including
the dynamic mechanical properties) of pure polyurethane (PU) and
PU/clay nanocomposites, were measured. The modified organoclay
had a remarkably beneficial effect on the strength and elongation at
break of the nanocomposites, which both increased with increasing
clay content with the increase of the tensile strength of more than
214% and 267% by the addition of only 5 wt% of the
montmorillonite CTAB-mont PU and ODA-mont PU, respectively.
Abstract: Industrial surveys shows that manufacturing
companies define the qualities of thermal removing process based on
the dimension and physical appearance of the cutting material
surface. Therefore, the roughness of the surface area of the material
cut by the plasma arc cutting process and the rate of the removed
material by the manual plasma arc cutting machine was importantly
considered. Plasma arc cutter Selco Genesis 90 was used to cut
Standard AISI 1017 Steel of 200 mm x100 mm x 6 mm manually
based on the selected parameters setting. The material removal rate
(MRR) was measured by determining the weight of the specimens
before and after the cutting process. The surface roughness (SR)
analysis was conducted using Mitutoyo CS-3100 to determine the
average roughness value (Ra). Taguchi method was utilized to
achieve optimum condition for both outputs studied. The
microstructure analysis in the region of the cutting surface is
performed using SEM. The results reveal that the SR values are
inversely proportional to the MRR values. The quality of the surface
roughness depends on the dross peak that occurred after the cutting
process.
Abstract: Cassava is one of the top five crops in Cameroon. Its
evolution has remained constant since the independence period and
the production has more than tripled. It is a crop with multiple
industrial capacities but the sector-s business opportunities are
underexploited. Using Strengths, Weaknesses, Opportunities and
Threats analysis method, this paper examines the cassava actual state.
It appraises the sector-s strengths (S), considers suitable measures to
strengthen weaknesses (W), evaluates strategies to fully benefit from
the sector numerous business opportunities (O) and explore means to
convert threats (T) into opportunities. Data were collected from the
ministry of agriculture and rural development and different actors.
The results show that cassava sector embodies many business
opportunities and stands as a raw material provider for many
industries but ultimately requires challenges to be tackled
appropriately.
Abstract: the purpose of this research is to identify and clarify
factors which have positive effect among user satisfaction and their
social networking through websites. The examined factors in this
research are; innovation, ease of use, trustworthy and customer
support which are defined as satisfaction factors. To obtain reliable
research approaches and to have better result in this research four
hypothesizes used to test. This hypothesis testing has been done by
correlation, regression and test of normality by using “SPSS16" also
the data which was analyzed by this software. this data was gathered
from prepaid questionnaire.
Abstract: Electronic nose (array of chemical sensors) are widely
used in food industry and pollution control. Also it could be used to
locate or detect the direction of the source of emission odors. Usually
this task is performed by electronic nose (ENose) cooperated with
mobile vehicles, but when a source is instantaneous or surrounding is
hard for vehicles to reach, problem occurs. Thus a method for
stationary ENose to detect the direction of the source and locate the
source will be required. A novel method which uses the ratio between
the responses of different sensors as a discriminant to determine the
direction of source in natural wind surroundings is presented in this
paper. The result shows that the method is accurate and easily to be
implemented. This method could be also used in movably, as an
optimized algorithm for robot tracking source location.
Abstract: Text Mining is an important step of Knowledge
Discovery process. It is used to extract hidden information from notstructured
o semi-structured data. This aspect is fundamental because
much of the Web information is semi-structured due to the nested
structure of HTML code, much of the Web information is linked,
much of the Web information is redundant. Web Text Mining helps
whole knowledge mining process to mining, extraction and
integration of useful data, information and knowledge from Web
page contents.
In this paper, we present a Web Text Mining process able to
discover knowledge in a distributed and heterogeneous multiorganization
environment. The Web Text Mining process is based on
flexible architecture and is implemented by four steps able to
examine web content and to extract useful hidden information
through mining techniques. Our Web Text Mining prototype starts
from the recovery of Web job offers in which, through a Text Mining
process, useful information for fast classification of the same are
drawn out, these information are, essentially, job offer place and
skills.
Abstract: In this study the elastic-plastic stress distribution in
weld-bonded joint, fabricated from austenitic stainless steel (AISI
304) sheet of 1.00 mm thickness and Epoxy adhesive Araldite 2011,
subjected to axial loading is investigated. This is needed to improve
design procedures and welding codes, and saving efforts in the
cumbersome experiments and analysis. Therefore, a complete 3-D
finite element modelling and analysis of spot welded, bonded and
weld-bonded joints under axial loading conditions is carried out. A
comprehensive systematic experimental program is conducted to
determine many properties and quantities, of the base metals and the
adhesive, needed for FE modelling, such like the elastic – plastic
properties, modulus of elasticity, fracture limit, the nugget and heat
affected zones (HAZ) properties, etc. Consequently, the finite
element models developed, for each case, are used to evaluate
stresses distributions across the entire joint, in both the elastic and
plastic regions. The stress distribution curves are obtained,
particularly in the elastic regions and found to be consistent and in
excellent agreement with the published data. Furthermore, the
stresses distributions are obtained in the weld-bonded joint and
display the best results with almost uniform smooth distribution
compared to spot and bonded cases. The stress concentration peaks at
the edges of the weld-bonded region, are almost eliminated resulting
in achieving the strongest joint of all processes.
Abstract: The overriding goal of software engineering is to
provide a high quality system, application or a product. To achieve
this goal, software engineers must apply effective methods coupled
with modern tools within the context of a mature software process
[2]. In addition, it is also must to assure that high quality is realized.
Although many quality measures can be collected at the project
levels, the important measures are errors and defects. Deriving a
quality measure for reusable components has proven to be
challenging task now a days. The results obtained from the study are
based on the empirical evidence of reuse practices, as emerged from
the analysis of industrial projects. Both large and small companies,
working in a variety of business domains, and using object-oriented
and procedural development approaches contributed towards this
study. This paper proposes a quality metric that provides benefit at
both project and process level, namely defect removal efficiency
(DRE).
Abstract: High pressure adsorption of carbon dioxide on zeolite
13X was investigated in the pressure range (0 to 4) Mpa and
temperatures 298, 308 and 323K. The data fitting is accomplished
with the Toth, UNILAN, Dubinin-Astakhov and virial adsorption
models which are generally used for micro porous adsorbents such as
zeolites. Comparison with experimental data from the literature
indicated that the virial model would best determine results. These
results may be partly attributed to the flexibility of the virial model
which can accommodate as many constants as the data warrants.
Abstract: Inventory decisional environment of short life-cycle
products is full of uncertainties arising from randomness and
fuzziness of input parameters like customer demand requiring
modeling under hybrid uncertainty. Prior inventory models
incorporating fuzzy demand have unfortunately ignored stochastic
variation of demand. This paper determines an unambiguous optimal
order quantity from a set of n fuzzy observations in a newsvendor
inventory setting in presence of fuzzy random variable demand
capturing both fuzzy perception and randomness of customer
demand. The stress of this paper is in providing solution procedure
that attains optimality in two steps with demand information
availability in linguistic phrases leading to fuzziness along with
stochastic variation. The first step of solution procedure identifies
and prefers one best fuzzy opinion out of all expert opinions and the
second step determines optimal order quantity from the selected
event that maximizes profit. The model and solution procedure is
illustrated with a numerical example.
Abstract: In this article, the authors reviewed and analyzed the survey materials similarities ornament proto-Turkic and northern Indians. The study examined the materials scientists - geneticists, archaeologists, anthropologists. Numerous studies of scientists from different directions once again prove the relevance of the topic. The authors approached the subject from an artistic side. The study authors have made the appropriate conclusions. This publication is based on the proceedings of the investigation.
Abstract: Clustering algorithms are attractive for the task of class identification in spatial databases. However, the application to large spatial databases rises the following requirements for clustering algorithms: minimal requirements of domain knowledge to determine the input parameters, discovery of clusters with arbitrary shape and good efficiency on large databases. The well-known clustering algorithms offer no solution to the combination of these requirements. In this paper, a density based clustering algorithm (DCBRD) is presented, relying on a knowledge acquired from the data by dividing the data space into overlapped regions. The proposed algorithm discovers arbitrary shaped clusters, requires no input parameters and uses the same definitions of DBSCAN algorithm. We performed an experimental evaluation of the effectiveness and efficiency of it, and compared this results with that of DBSCAN. The results of our experiments demonstrate that the proposed algorithm is significantly efficient in discovering clusters of arbitrary shape and size.
Abstract: Stormwater wetlands have been mainly designed in an
empirical approach for water quality improvement, with little
quantitative understanding of the internal microbial processes. This
study investigated into heterotrophic bacterial production rate,
heterotrophic bacterial mineralization percentage, and algal biomass
in hypertrophic and eutrophic surface flow stormwater wetlands.
Compared to a nearby wood leachate treatment wetland, the
stormwater wetlands had much higher chlorophyll-a concentrations.
The eutrophic stormwater wetland had improved water quality,
whereas the hypertrophic stormwater wetland had degraded water
quality. Heterotrophic bacterial activities in water were limited in the
stormwater wetlands due to competition of algal growth for nutrients.
The relative contribution of biofilms to the overall heterotrophic
activities was higher in the stormwater wetlands than that in the wood
leachate treatment wetland.
Abstract: At present, the tendency to implement the conditionbased
maintenance (CBM), which allows the optimization of the
expenses for equipment monitoring, is more and more evident; also,
the transformer substations with remote monitoring are increasingly
used. This paper reviews all the advantages of the on-line monitoring
and presents an equipment for on-line monitoring of bushings, which
is the own contribution of specialists who are the authors of this
paper. The paper presents a study of the temperature field, using the
finite element method. For carrying out this study, the 3D modelling
of the above mentioned bushing was performed. The analysis study is
done taking into account the extreme thermal stresses, focusing at the
level of the first cooling wing section of the ceramic insulator. This
fact enables to justify the tanδ variation in time, depending on the
transformer loading and the environmental conditions. With a view
to reducing the variation of dielectric losses in bushing insulation, the
use of ferrofuids instead of mineral oils is proposed.
Abstract: In this paper a data miner based on the learning
automata is proposed and is called LA-miner. The LA-miner extracts
classification rules from data sets automatically. The proposed
algorithm is established based on the function optimization using
learning automata. The experimental results on three benchmarks
indicate that the performance of the proposed LA-miner is
comparable with (sometimes better than) the Ant-miner (a data miner
algorithm based on the Ant Colony optimization algorithm) and CNZ
(a well-known data mining algorithm for classification).
Abstract: Statistical selection procedures are used to select the
best simulated system from a finite set of alternatives. In this paper,
we present a procedure that can be used to select the best system
when the number of alternatives is large. The proposed procedure
consists a combination between Ranking and Selection, and Ordinal
Optimization procedures. In order to improve the performance of Ordinal
Optimization, Optimal Computing Budget Allocation technique
is used to determine the best simulation lengths for all simulation
systems and to reduce the total computation time. We also argue
the effect of increment in simulation samples for the combined
procedure. The results of numerical illustration show clearly the effect
of increment in simulation samples on the proposed combination of
selection procedure.
Abstract: A method is presented for the construction of arbitrary
even-input sorting networks exhibiting better properties than the
networks created using a conventional technique of the same type.
The method was discovered by means of a genetic algorithm combined
with an application-specific development. Similarly to human
inventions in the area of theoretical computer science, the evolved
invention was analyzed: its generality was proven and area and time
complexities were determined.
Abstract: A study of electromagnetic flow meter is presented in the paper. Comparison has been made between the analytical and the numerical results by the use of FEM numerical analysis (Quick Field 5.6) for determining polarization voltage through the circle cross section of the polarization transducer. Exciting and geometrical parameters increasing its effectiveness has been examined. The aim is to obtain maximal output signal. The investigations include different variants of the magnetic flux density distribution around the tube: homogeneous field of magnitude Bm, linear distribution with maximal value Bm and trapezium distribution conserving the same exciting magnetic energy as the homogeneous field.
Abstract: Fick's second law equations for unsteady state
diffusion of salt into the potato tissues were solved numerically. The
set of equations resulted from implicit modeling were solved using
Thomas method to find the salt concentration profiles in solid phase.
The needed effective diffusivity and equilibrium distribution
coefficient were determined experimentally. Cylindrical samples of
potato were infused with aqueous NaCl solutions of 1-3%
concentrations, and variations in salt concentrations of brine were
determined over time. Solute concentrations profiles of samples were
determined by measuring salt uptake of potato slices. For the studied
conditions, equilibrium distribution coefficients were found to be
dependent on salt concentrations, whereas the effective diffusivity
was slightly affected by brine concentration.
Abstract: Unsteady magnetohydrodynamics (MHD) boundary
layer flow and heat transfer over a continuously stretching surface in
the presence of radiation is examined. By similarity transformation,
the governing partial differential equations are transformed to a set of
ordinary differential equations. Numerical solutions are obtained by
employing the Runge-Kutta-Fehlberg method scheme with shooting
technique in Maple software environment. The effects of
unsteadiness parameter, radiation parameter, magnetic parameter and
Prandtl number on the heat transfer characteristics are obtained and
discussed. It is found that the heat transfer rate at the surface
increases as the Prandtl number and unsteadiness parameter increase
but decreases with magnetic and radiation parameter.