Abstract: The effect of streamwise conduction on the thermal
characteristics of forced convection for nanofluidic flow in
rectangular microchannel heat sinks under isothermal wall has been
investigated. By applying the fin approach, models with and without
streamwise conduction term in the energy equation were developed
for hydrodynamically and thermally fully-developed flow. These two
models were solved to obtain closed form analytical solutions for the
nanofluid and solid wall temperature distributions and the analysis
emphasized details of the variations induced by the streamwise
conduction on the nanofluid heat transport characteristics. The effects
of the Peclet number, nanoparticle volume fraction, thermal
conductivity ratio on the thermal characteristics of forced convection
in microchannel heat sinks are analyzed. Due to the anomalous
increase in the effective thermal conductivity of nanofluid compared
to its base fluid, the effect of streamwise conduction is expected to be
more significant. This study reveals the significance of the effect of
streamwise conduction under certain conditions of which the
streamwise conduction should not be neglected in the forced
convective heat transfer analysis of microchannel heat sinks.
Abstract: The present work describes a computational study of
aerodynamic characteristics of GLC305 airfoil clean and with 16.7
min ice shape (rime 212) and 22.5 min ice shape (glaze 944).The
performance of turbulence models SA, Kε, Kω Std, and Kω SST
model are observed against experimental flow fields at different
Mach numbers 0.12, 0.21, 0.28 in a range of Reynolds numbers
3x106, 6x106, and 10.5x106 on clean and iced aircraft airfoil
GLC305. Numerical predictions include lift, drag and pitching
moment coefficients at different Mach numbers and at different angle
of attacks were done. Accuracy of solutions with respect to the
effects of turbulence models, variation of Mach number, initial
conditions, grid resolution and grid spacing near the wall made the
study much sensitive. Navier Stokes equation based computational
technique is used. Results are very close to the experimental results.
It has seen that SA and SST models are more efficient than Kε and
Kω standard in under study problem.
Abstract: In this paper, we study the existence, the boundedness and the asymptotic behavior of the positive solutions of a fuzzy nonlinear difference equations xn+1 = A + k i=0 Bi xn-i , n= 0, 1, · · · . where (xn) is a sequence of positive fuzzy numbers, A,Bi and the initial values x-k, x-k+1, · · · , x0 are positive fuzzy numbers. k ∈ {0, 1, 2, · · ·}.
Abstract: A new nonlinear sum-difference inequality in two variables
which generalize some existing results and can be used as handy
tools in the analysis of certain partial difference equation is discussed.
An example to show boundedness of solutions of a difference value
problem is also given.
Abstract: The purpose of this study is to identify the underlying
causes of late payment from the contractors- perspective in the
Malaysian construction industry and to recommend effective solutions
to mitigate late payment problems. The target groups of respondents in
this study were Grades G3, G5, G6 and G7 contractors with
specialization in building works and civil engineering works registered
with the Construction Industry Development Board (CIDB) in
Malaysia. Results from this study were analyzed with Statistical
Package for the Social Science (SPSS 15.0). From this study, it was
found that respondents have highest ranked five significant variables
out of a total of forty-one variables which can caused late payment
problems: a) cash flow problems due to deficiencies in client-s
management capacity (mean = 3.96); b) client-s ineffective utilization
of funds (mean = 3.88); c) scarcity of capital to finance the project
(mean = 3.81); d) clients failure to generate income from bank when
sales of houses do not hit the targeted amount (mean=3.72); and e)
poor cash flow because of lack of proper process implementation,
delay in releasing of the retention monies to contractor and delay in the
evaluation and certification of interim and final payment (mean =
3.66).
Abstract: In this paper, a food chain model with Holling type II functional response on time scales is investigated. By using the Mawhin-s continuation theorem in coincidence degree theory, sufficient conditions for existence of periodic solutions are obtained.
Abstract: Several optimization algorithms specifically applied to
the problem of Operation Planning of Hydrothermal Power Systems
have been developed and are used. Although providing solutions to
various problems encountered, these algorithms have some
weaknesses, difficulties in convergence, simplification of the original
formulation of the problem, or owing to the complexity of the
objective function. Thus, this paper presents the development of a
computational tool for solving optimization problem identified and to
provide the User an easy handling. Adopted as intelligent
optimization technique, Genetic Algorithms and programming
language Java. First made the modeling of the chromosomes, then
implemented the function assessment of the problem and the
operators involved, and finally the drafting of the graphical interfaces
for access to the User. The program has managed to relate a coherent
performance in problem resolution without the need for
simplification of the calculations together with the ease of
manipulating the parameters of simulation and visualization of output
results.
Abstract: With the widespread growth of applications of
Wireless Sensor Networks (WSNs), the need for reliable security
mechanisms these networks has increased manifold. Many security
solutions have been proposed in the domain of WSN so far. These
solutions are usually based on well-known cryptographic
algorithms.
In this paper, we have made an effort to survey well known
security issues in WSNs and study the behavior of WSN nodes that
perform public key cryptographic operations. We evaluate time
and power consumption of public key cryptography algorithm for
signature and key management by simulation.
Abstract: This paper is to present context-aware sensor grid
framework for agriculture and its design challenges. Use of sensor
networks in the domain of agriculture is not new. However, due to
the unavailability of any common framework, solutions that are
developed in this domain are location, environment and problem
dependent. Keeping the need of common framework for agriculture,
Context-Aware Sensor Grid Framework is proposed. It will be
helpful in developing solutions for majority of the problems related
to irrigation, pesticides spray, use of fertilizers, regular monitoring of
plot and yield etc. due to the capability of adjusting according to
location and environment. The proposed framework is composed of
three layer architecture including context-aware application layer,
grid middleware layer and sensor network layer.
Abstract: The aim of this paper is to study the oblique
stagnation point flow on vertical plate with uniform surface heat flux
in presence of magnetic field. Using Stream function, partial
differential equations corresponding to the momentum and energy
equations are converted into non-linear ordinary differential
equations. Numerical solutions of these equations are obtained using
Runge-Kutta Fehlberg method with the help of shooting technique.
In the present work the effects of striking angle, magnetic field
parameter, Grashoff number, the Prandtl number on velocity and heat
transfer characteristics have been discussed. Effect of above
mentioned parameter on the position of stagnation point are also
studied.
Abstract: Construction cost in India is increasing at around 50
per cent over the average inflation levels. It have registered increase
of up to 15 per cent every year, primarily due to cost of basic
building materials such as steel, cement, bricks, timber and other
inputs as well as cost of labour. As a result, the cost of construction
using conventional building materials and construction is becoming
beyond the affordable limits particularly for low-income groups of
population as well as a large cross section of the middle - income
groups. Therefore, there is a need to adopt cost-effective construction
methods either by up-gradation of traditional technologies using local
resources or applying modern construction materials and techniques
with efficient inputs leading to economic solutions. This has become
the most relevant aspect in the context of the large volume of housing
to be constructed in both rural and urban areas and the consideration
of limitations in the availability of resources such as building
materials and finance. This paper makes an overview of the housing
status in India and adoption of appropriate and cost effective
technologies in the country.
Abstract: Dust acoustic solitary waves are studied in warm
dusty plasma containing negatively charged dusts, nonthermal ions
and Boltzmann distributed electrons. Sagdeev pseudopotential
method is used in order to investigate solitary wave solutions in the
plasmas. The existence of compressive and rarefractive solitons is
studied.
Abstract: Automatic methods of detecting changes through
satellite imaging are the object of growing interest, especially
beca²use of numerous applications linked to analysis of the Earth’s
surface or the environment (monitoring vegetation, updating maps,
risk management, etc...). This work implemented spatial analysis
techniques by using images with different spatial and spectral
resolutions on different dates. The work was based on the principle
of control charts in order to set the upper and lower limits beyond
which a change would be noted. Later, the a contrario approach was
used. This was done by testing different thresholds for which the
difference calculated between two pixels was significant. Finally,
labeled images were considered, giving a particularly low difference
which meant that the number of “false changes” could be estimated
according to a given limit.
Abstract: In this paper, the C1-conforming finite element method is analyzed for a class of nonlinear fourth-order hyperbolic partial differential equation. Some a priori bounds are derived using Lyapunov functional, and existence, uniqueness and regularity for the weak solutions are proved. Optimal error estimates are derived for both semidiscrete and fully discrete schemes.
Abstract: The clustering ensembles combine multiple partitions
generated by different clustering algorithms into a single clustering
solution. Clustering ensembles have emerged as a prominent method
for improving robustness, stability and accuracy of unsupervised
classification solutions. So far, many contributions have been done to
find consensus clustering. One of the major problems in clustering
ensembles is the consensus function. In this paper, firstly, we
introduce clustering ensembles, representation of multiple partitions,
its challenges and present taxonomy of combination algorithms.
Secondly, we describe consensus functions in clustering ensembles
including Hypergraph partitioning, Voting approach, Mutual
information, Co-association based functions and Finite mixture
model, and next explain their advantages, disadvantages and
computational complexity. Finally, we compare the characteristics of
clustering ensembles algorithms such as computational complexity,
robustness, simplicity and accuracy on different datasets in previous
techniques.
Abstract: Clustering is a very well known technique in data mining. One of the most widely used clustering techniques is the kmeans algorithm. Solutions obtained from this technique depend on the initialization of cluster centers and the final solution converges to local minima. In order to overcome K-means algorithm shortcomings, this paper proposes a hybrid evolutionary algorithm based on the combination of PSO, SA and K-means algorithms, called PSO-SA-K, which can find better cluster partition. The performance is evaluated through several benchmark data sets. The simulation results show that the proposed algorithm outperforms previous approaches, such as PSO, SA and K-means for partitional clustering problem.
Abstract: A new strain of Type A influenza virus can cause the
transmission of H1N1 virus. This virus can spread between the
people by coughing and sneezing. Because the people are always
movement, so this virus can be easily spread. In this study, we
construct the dynamical network model of H1N1 virus by separating
the human into five groups; susceptible, exposed, infectious,
quarantine and recovered groups. The movement of people between
houses (local level) is considered. The behaviors of solutions to our
dynamical model are shown for the different parameters.
Abstract: Solutions for the temperature profile around a moving
heat source are obtained using both analytic and finite element
(FEM) methods. Analytic and FEM solutions are applied to study the
temperature profile in welding. A moving heat source is represented
using both point heat source and uniform distributed disc heat source
models. Analytic solutions are obtained by solving the partial
differential equation for energy conservation in a solid, and FEM
results are provided by simulating welding using the ANSYS
software. Comparison is made for quasi steady state conditions. The
results provided by the analytic solutions are in good agreement with
results obtained by FEM.
Abstract: The main aim of this paper is to investigate the exponential stability of the Euler method for a stochastic age-dependent population equations with Poisson random measures. It is proved that the Euler scheme is exponentially stable in mean square sense. An example is given for illustration.
Abstract: This paper reviews designs of the built environment
from a sustainability perspective, emphasizing their importance in
achieving ecological and sustainable economic objectives. The built
environment has traditionally resulted in loss of biodiversity,
extinction of some species, climate change, excessive water use, land
degradation, space depletion, waste accumulation, energy
consumption and environmental pollution. Materials used like
plastics, metals, bricks, concrete, cement, natural aggregates, glass
and plaster have wreaked havoc on the earth´s resources, since they
have high levels of embodied energy hence not sustainable.
Additional resources are consumed during use and disposal phases.
Proposed designs for sustainability solutions include: ecological
sanitation and eco-efficiency systems that ensure social, economic,
environmental and technical sustainability. Renewable materials and
energy systems, passive cooling and heating systems and material
and energy reduction, reuse and recycling can improve the sector.
These ideas are intended to inform the field of ecological design of
the built environment.