Abstract: Stick models are widely used in studying the
behaviour of straight as well as skew bridges and viaducts subjected
to earthquakes while carrying out preliminary studies. The
application of such models to highly curved bridges continues to
pose challenging problems. A viaduct proposed in the foothills of the
Himalayas in Northern India is chosen for the study. It is having 8
simply supported spans @ 30 m c/c. It is doubly curved in horizontal
plane with 20 m radius. It is inclined in vertical plane as well. The
superstructure consists of a box section. Three models have been
used: a conventional stick model, an improved stick model and a 3D
finite element model. The improved stick model is employed by
making use of body constraints in order to study its capabilities. The
first 8 frequencies are about 9.71% away in the latter two models.
Later the difference increases to 80% in 50th mode. The viaduct was
subjected to all three components of the El Centro earthquake of May
1940. The numerical integration was carried out using the Hilber-
Hughes-Taylor method as implemented in SAP2000. Axial forces
and moments in the bridge piers as well as lateral displacements at
the bearing levels are compared for the three models. The maximum
difference in the axial forces and bending moments and
displacements vary by 25% between the improved and finite element
model. Whereas, the maximum difference in the axial forces,
moments, and displacements in various sections vary by 35%
between the improved stick model and equivalent straight stick
model. The difference for torsional moment was as high as 75%. It is
concluded that the stick model with body constraints to model the
bearings and expansion joints is not desirable in very sharp S curved
viaducts even for preliminary analysis. This model can be used only
to determine first 10 frequency and mode shapes but not for member
forces. A 3D finite element analysis must be carried out for
meaningful results.
Abstract: Possible advantages of technology in educational
context required the defining boundaries of formal and informal
learning. Increasing opportunity to ubiquitous learning by
technological support has revealed a question of how to discover
the potential of individuals in the spontaneous environments such as
social networks. This seems to be related with the question of what
purposes in social networks have been being used? Social networks
provide various advantages in educational context as collaboration,
knowledge sharing, common interests, active participation and
reflective thinking. As a consequence of these, the purpose of this
study is composed of proposing a new model that could determine
factors which effect adoption of social network applications for usage
in educational context. While developing a model proposal, the
existing adoption and diffusion models have been reviewed and they
are thought to be suitable on handling an original perspective instead
of using completely other diffusion or acceptance models because of
different natures of education from other organizations. In the
proposed model; social factors, perceived ease of use, perceived
usefulness and innovativeness are determined four direct constructs
that effect adoption process. Facilitating conditions, image,
subjective norms and community identity are incorporated to model
as antecedents of these direct four constructs.
Abstract: Perishable goods constitute a large portion of retailer inventory and lose value with time due to deterioration and/or obsolescence. Retailers dealing with such goods required considering the factors of short shelf life and the dependency of sales on inventory displayed in determining optimal procurement policy. Many retailers follow the practice of using two bins - primary bin sales fresh items at a list price and secondary bin sales unsold items at a discount price transferred from primary bin on attaining certain age. In this paper, mathematical models are developed for primary bin and for secondary bin that maximizes profit with decision variables of order quantities, optimal review period and optimal selling price at secondary bin. The demand rates in two bins are assumed to be deterministic and dependent on displayed inventory level, price and age but independent of each other. The validity of the model is shown by solving an example and the sensitivity analysis of the model is also reported.
Abstract: A numerical study on the influence of electroosmotic flow on analyte preconcentration by isotachophoresis ( ITP) is made. We consider that the double layer induced electroosmotic flow ( EOF) counterbalance the electrophoretic velocity and a stationary ITP stacked zones results. We solve the Navier-Stokes equations coupled with the Nernst-Planck equations to determine the local convective velocity and the preconcentration dynamics of ions. Our numerical algorithm is based on a finite volume method along with a secondorder upwind scheme. The present numerical algorithm can capture the the sharp boundaries of step-changes ( plateau mode) or zones of steep gradients ( peak mode) accurately. The convection of ions due to EOF reduces the resolution of the ITP transition zones and produces a dispersion in analyte zones. The role of the electrokinetic parameters which induces dispersion is analyzed. A one-dimensional model for the area-averaged concentrations based on the Taylor-Aristype effective diffusivity is found to be in good agreement with the computed solutions.
Abstract: In this research sodium bicarbonate (NaHCO3) was introduced to generate carbon dioxide gas (CO2) to the existing nitrogen gas (N2) of elastomeric foam, to lower thermal conductivity (K). Various loadings of NaHCO3 (0 to 60 phr) were added into the azodicarbonamide (AZC)-containing compound and its properties were then determined. Two vulcanization methods, i.e., hot air and infrared (IR), were employed and compared in this study. Results revealed that compound viscosity tended to increase slightly with increasing NaHCO3 content but cure time was delayed. The effect of NaHCO3 content on thermal conductivity depended on the vulcanization method. For hot air method, the thermal conductivity was insignificantly changed with increasing NaHCO3 up to 40 phr whereas it tended to decrease gradually for IR method. At higher NaHCO3 content (60 phr), unexpected increase of thermal conductivity was observed. The water absorption was also determined and foam structures were then used to explain the results.
Abstract: In this paper, a Cooperative Multi-robot for Carrying
Targets (CMCT) algorithm is proposed. The multi-robot team
consists of three robots, one is a supervisor and the others are
workers for carrying boxes in a store of 100×100 m2. Each robot has
a self recharging mechanism. The CMCT minimizes robot-s worked
time for carrying many boxes during day by working in parallel. That
is, the supervisor detects the required variables in the same time
another robots work with previous variables. It works with
straightforward mechanical models by using simple cosine laws. It
detects the robot-s shortest path for reaching the target position
avoiding obstacles by using a proposed CMCT path planning
(CMCT-PP) algorithm. It prevents the collision between robots
during moving. The robots interact in an ad hoc wireless network.
Simulation results show that the proposed system that consists of
CMCT algorithm and its accomplished CMCT-PP algorithm
achieves a high improvement in time and distance while performing
the required tasks over the already existed algorithms.
Abstract: The presence of heavy metals in the environment
could constitute a hazard to food security and public health. These
can be accumulated in aquatic animals such as fish. Samples of four
popular brands of canned fish in the Iranian market (yellowfin tuna,
common Kilka, Kawakawa and longtail tuna) were analyzed for level
of Cr after wet digestion with acids using graphite furnace atomic
absorption spectrophotometry. The mean concentrations for Cr in the
different brands were: 2.57, 3.24, 3.16 and 1.65 μg/g for brands A, B,
C and D respectively. Significant differences were observed in the Cr
levels between all of the different brands of canned fish evaluated in
this study. The Cr concentrations for the varieties of canned fishes
were generally within the FAO/WHO, U.S. FDA and U.S. EPA
recommended limits for fish.
Abstract: In this paper we proposed a method for finding video
frames representing one sign in the finger alphabet. The method is
based on determining hands location, segmentation and the use of
standard video quality evaluation metrics. Metric calculation is
performed only in regions of interest. Sliding mechanism for finding
local extrema and adaptive threshold based on local averaging is used
for key frames selection. The success rate is evaluated by recall,
precision and F1 measure. The method effectiveness is compared
with metrics applied to all frames. Proposed method is fast, effective
and relatively easy to realize by simple input video preprocessing
and subsequent use of tools designed for video quality measuring.
Abstract: In today's day and age, one of the important topics in
information security is authentication. There are several alternatives
to text-based authentication of which includes Graphical Password
(GP) or Graphical User Authentication (GUA). These methods stems
from the fact that humans recognized and remembers images better
than alphanumerical text characters. This paper will focus on the
security aspect of GP algorithms and what most researchers have
been working on trying to define these security features and
attributes. The goal of this study is to develop a fuzzy decision model
that allows automatic selection of available GP algorithms by taking
into considerations the subjective judgments of the decision makers
who are more than 50 postgraduate students of computer science. The
approach that is being proposed is based on the Fuzzy Analytic
Hierarchy Process (FAHP) which determines the criteria weight as a
linear formula.
Abstract: Perturbed-Chain Statistical Association Fluid Theory (PC-SAFT) equation of state (EOS) is a modified SAFT EOS with three pure component specific parameters: segment number (m), diameter (σ) and energy (ε). These PC-SAFT parameters need to be determined for each component under the conditions of interest by fitting experimental data, such as vapor pressure, density or heat capacity. PC-SAFT parameters for propane, ethylene and hydrogen in supercritical region were successfully estimated by fitting experimental density data available in literature. The regressed PCSAFT parameters were compared with the literature values by means of estimating pure component density and calculating average absolute deviation between the estimated and experimental density values. PC-SAFT parameters available in literature especially for ethylene and hydrogen estimated density in supercritical region reasonably well. However, the regressed PC-SAFT parameters performed better in supercritical region than the PC-SAFT parameters from literature.
Abstract: In Algeria, some fruit trees produce fruits in free nature. Such trees are Celtis australis, Crataegus azarolus, Crataegus monogyna and Zizyphus lotus. In spite of their appreciable consumption, their nutritional value remains unknown. The objective of this study is the determination of sugars in the pulpe and almond of the above fruits. The biochemical analysis shows that these fruits present interesting contents of soluble sugars which confers significant caloric intakes to them. As well as significant fibres which give them therapeutic and industrial benefits? The analysis of the almonds shows that it contains considerable contents of sugars which enable them to be an energetic food.
Abstract: Power loss reduction is one of the main targets in power industry and so in this paper, the problem of finding the optimal configuration of a radial distribution system for loss reduction is considered. Optimal reconfiguration involves the selection of the best set of branches to be opened ,one each from each loop, for reducing resistive line losses , and reliving overloads on feeders by shifting the load to adjacent feeders. However ,since there are many candidate switching combinations in the system ,the feeder reconfiguration is a complicated problem. In this paper a new approach is proposed based on a simple optimum loss calculation by determining optimal trees of the given network. From graph theory a distribution network can be represented with a graph that consists a set of nodes and branches. In fact this problem can be viewed as a problem of determining an optimal tree of the graph which simultaneously ensure radial structure of each candidate topology .In this method the refined genetic algorithm is also set up and some improvements of algorithm are made on chromosome coding. In this paper an implementation of the algorithm presented by [7] is applied by modifying in load flow program and a comparison of this method with the proposed method is employed. In [7] an algorithm is proposed that the choice of the switches to be opened is based on simple heuristic rules. This algorithm reduce the number of load flow runs and also reduce the switching combinations to a fewer number and gives the optimum solution. To demonstrate the validity of these methods computer simulations with PSAT and MATLAB programs are carried out on 33-bus test system. The results show that the performance of the proposed method is better than [7] method and also other methods.
Abstract: Network reconfiguration in distribution system is realized by changing the status of sectionalizing switches to reduce the power loss in the system. This paper presents a new method which applies an artificial bee colony algorithm (ABC) for determining the sectionalizing switch to be operated in order to solve the distribution system loss minimization problem. The ABC algorithm is a new population based metaheuristic approach inspired by intelligent foraging behavior of honeybee swarm. The advantage of ABC algorithm is that it does not require external parameters such as cross over rate and mutation rate as in case of genetic algorithm and differential evolution and it is hard to determine these parameters in prior. The other advantage is that the global search ability in the algorithm is implemented by introducing neighborhood source production mechanism which is a similar to mutation process. To demonstrate the validity of the proposed algorithm, computer simulations are carried out on 14, 33, and 119-bus systems and compared with different approaches available in the literature. The proposed method has outperformed the other methods in terms of the quality of solution and computational efficiency.
Abstract: Aloe vera has been used worldwide both for
pharmaceutical, food, and cosmetic industries due to the plethora of
biological activities of some of its metabolites. The aim of this study
was to evaluate the antifungal and antioxidant activities of the leaf
extract. The antifungal activity was determined by the agar-well
diffusion method against plant and human fungal pathogens. The
methanol and ethanol portions of the extracts studied were more
bioactive than ethyl acetate portion. It was also observed that the
activity was more pronounced on plant pathogen than human
pathogen except Candida albicans. This is an indication that the
extract has the potential to treat plant fungal infections. The Aloe
extract showed the significant antioxidant activity by the DPPH
radical scavenging method. Therefore, the Aloe extract provided as
natural antioxidant has been used in health foods for medical and
preservative purposes.
Abstract: The use of power system stabilizers (PSSs) to damp
power system swing mode of oscillations is practical important. Our
purpose is to retune the power system stabilizer (PSS1A) parameters
in Unitrol D produced by ABB– was installed in 1995in Benghazi
North Power Plants (BNPPs) at General Electricity Company of
Libya (GECOL). The optimal values of the power system stabilizer
(PSS1A) parameters are determined off-line by a particle swarm
optimization technique (PSO). The objective is to damp the local and
inter-area modes of oscillations that occur following power system
disturbances. The retuned power system stabilizer (PSS1A) can cope
with large disturbance at different operating points and has enhanced
power system stability.
Abstract: Levan, an exopolysaccharide, was produced by
Microbacterium laevaniformans and its yield was characterized as a
function of concentrations of date syrup, sucrose and the fermentation
time. The optimum condition for levan production from sucrose was
at concentration of 20% sucrose for 48 h and for date syrup was 25%
for 48 h. The results show that an increase in fermentation time
caused a decrease in the levan production at all concentrations of date
syrup tested. Under these conditions after 48 h in sucrose medium,
levan production reached 48.9 g/L and for date syrup reached 10.48
g/L . The effect of pH on the yield of the purified levan was examined
and the optimum pH for levan production was determined to be 6.0.
Levan was composed mainly of fructose residues when analyzed by
TLC and FT-IR spectroscopy. Date syrup is a cheap substrate widely
available in Iran and has potential for levan production. The thermal
stability of levan was assessed by Thermo Gravimetric Analysis
(TGA) that revealed the onset of decomposition near to 49°C for the
levan produced from sucrose and 51°C for the levan from date syrup.
DSC results showed a single Tg at 98°C for levan produced from
sucrose and 206 °C for levan from date syrup.
Abstract: This paper provides an in-depth study of Wireless
Sensor Network (WSN) application to monitor and control the
swiftlet habitat. A set of system design is designed and developed
that includes the hardware design of the nodes, Graphical User
Interface (GUI) software, sensor network, and interconnectivity for
remote data access and management. System architecture is proposed
to address the requirements for habitat monitoring. Such applicationdriven
design provides and identify important areas of further work
in data sampling, communications and networking. For this
monitoring system, a sensor node (MTS400), IRIS and Micaz radio
transceivers, and a USB interfaced gateway base station of Crossbow
(Xbow) Technology WSN are employed. The GUI of this monitoring
system is written using a Laboratory Virtual Instrumentation
Engineering Workbench (LabVIEW) along with Xbow Technology
drivers provided by National Instrument. As a result, this monitoring
system is capable of collecting data and presents it in both tables and
waveform charts for further analysis. This system is also able to send
notification message by email provided Internet connectivity is
available whenever changes on habitat at remote sites (swiftlet farms)
occur. Other functions that have been implemented in this system
are the database system for record and management purposes; remote
access through the internet using LogMeIn software. Finally, this
research draws a conclusion that a WSN for monitoring swiftlet
habitat can be effectively used to monitor and manage swiftlet
farming industry in Sarawak.
Abstract: In recent years, scanning probe atomic force
microscopy SPM AFM has gained acceptance over a wide spectrum
of research and science applications. Most fields focuses on physical,
chemical, biological while less attention is devoted to manufacturing
and machining aspects. The purpose of the current study is to assess
the possible implementation of the SPM AFM features and its
NanoScope software in general machining applications with special
attention to the tribological aspects of cutting tool. The surface
morphology of coated and uncoated as-received carbide inserts is
examined, analyzed, and characterized through the determination of
the appropriate scanning setting, the suitable data type imaging
techniques and the most representative data analysis parameters
using the MultiMode SPM AFM in contact mode. The NanoScope
operating software is used to capture realtime three data types
images: “Height", “Deflection" and “Friction". Three scan sizes are
independently performed: 2, 6, and 12 μm with a 2.5 μm vertical
range (Z). Offline mode analysis includes the determination of three
functional topographical parameters: surface “Roughness", power
spectral density “PSD" and “Section". The 12 μm scan size in
association with “Height" imaging is found efficient to capture every
tiny features and tribological aspects of the examined surface. Also,
“Friction" analysis is found to produce a comprehensive explanation
about the lateral characteristics of the scanned surface. Configuration
of many surface defects and drawbacks has been precisely detected
and analyzed.
Abstract: We have previously introduced an ultrasonic imaging
approach that combines harmonic-sensitive pulse sequences with a
post-beamforming quadratic kernel derived from a second-order
Volterra filter (SOVF). This approach is designed to produce images
with high sensitivity to nonlinear oscillations from microbubble
ultrasound contrast agents (UCA) while maintaining high levels of
noise rejection. In this paper, a two-step algorithm for computing the
coefficients of the quadratic kernel leading to reduction of tissue
component introduced by motion, maximizing the noise rejection and
increases the specificity while optimizing the sensitivity to the UCA
is presented. In the first step, quadratic kernels from individual
singular modes of the PI data matrix are compared in terms of their
ability of maximize the contrast to tissue ratio (CTR). In the second
step, quadratic kernels resulting in the highest CTR values are
convolved. The imaging results indicate that a signal processing
approach to this clinical challenge is feasible.
Abstract: A simple mobile engine-driven pneumatic paddy
collector made of locally available materials using local
manufacturing technology was designed, fabricated, and tested for
collecting and bagging of paddy dried on concrete pavement. The
pneumatic paddy collector had the following major components:
radial flat bladed type centrifugal fan, power transmission system,
bagging area, frame and the conveyance system. Results showed
significant differences on the collecting capacity, noise level, and fuel
consumption when rotational speed of the air mover shaft was varied.
Other parameters such as collecting efficiency, air velocity,
augmented cracked grain percentage, and germination rate were not
significantly affected by varying rotational speed of the air mover
shaft. The pneumatic paddy collector had a collecting efficiency of
99.33 % with a collecting capacity of 2685.00 kg/h at maximum
rotational speed of centrifugal fan shaft of about 4200 rpm. The
machine entailed an investment cost of P 62,829.25. The break-even
weight of paddy was 510,606.75 kg/yr at a collecting cost of 0.11
P/kg of paddy. Utilizing the machine for 400 hours per year
generated an income of P 23,887.73. The projected time needed to
recover cost of the machine based on 2685 kg/h collecting capacity
was 2.63 year.