Abstract: In this study, aerobic digestion of tannery industry
wastewater was carried out using mixed culture obtained from
common effluent treatment plant treating tannery wastewater. The
effect of pH, temperature, inoculum concentration, agitation speed
and initial substrate concentration on the reduction of organic matters
were found. The optimum conditions for COD reduction was found
to be pH - 7 (60%), temperature - 30ÔùªC (61%), inoculum
concentration - 2% (61%), agitation speed - 150rpm (65%) and initial
substrate concentration - 1560 mg COD/L (74%). Kinetics studies
were carried by using Monod model, First order, Diffusional model
and Singh model. From the results it was found that the Monod
model suits well for the degradation of tannery wastewater using
mixed microbial consortium.
Abstract: The wide increase and diffusion on telecommunication
technologies have caused a huge spread of electromagnetic sources
in most European Countries. Since the public is continuously being
exposed to electromagnetic radiation the possible health effects have
become the focus of population concerns. As a result, electromagnetic
field monitoring stations which control field strength in commercial
frequency bands are being placed on the flat roof of many buildings.
However there is no guidance on where to place them. This paper
presents an analysis of frequency, polarization and angles of incidence
of a plane wave which impinges on a flat roof security wall and its
dependence on electromagnetic field strength meters placement.
Abstract: In this paper we present discretization and decomposition methods for a multi-component transport model of a chemical vapor deposition (CVD) process. CVD processes are used to manufacture deposition layers or bulk materials. In our transport model we simulate the deposition of thin layers. The microscopic model is based on the heavy particles, which are derived by approximately solving a linearized multicomponent Boltzmann equation. For the drift-process of the particles we propose diffusionreaction equations as well as for the effects of heat conduction. We concentrate on solving the diffusion-reaction equation with analytical and numerical methods. For the chemical processes, modelled with reaction equations, we propose decomposition methods and decouple the multi-component models to simpler systems of differential equations. In the numerical experiments we present the computational results of our proposed models.
Abstract: In this paper a class of numerical methods to solve linear and nonlinear PDEs and also systems of PDEs is developed. The Differential Transform method associated with the Method of Lines (MoL) is used. The theory for linear problems is extended to the nonlinear case, and a recurrence relation is established. This method can achieve an arbitrary high-order accuracy in time. A variable stepsize algorithm and some numerical results are also presented.
Abstract: In cryptography, confusion and diffusion are very
important to get confidentiality and privacy of message in block
ciphers and stream ciphers. There are two types of network to provide
confusion and diffusion properties of message in block ciphers. They
are Substitution- Permutation network (S-P network), and Feistel
network. NLFS (Non-Linear feedback stream cipher) is a fast and
secure stream cipher for software application. NLFS have two modes
basic mode that is synchronous mode and self synchronous mode.
Real random numbers are non-deterministic. R-box (random box)
based on the dynamic properties and it performs the stochastic
transformation of data that can be used effectively meet the
challenges of information is protected from international destructive
impacts. In this paper, a new implementation of stochastic
transformation will be proposed.
Abstract: The focal spot of a high intensity focused ultrasound
transducer is small. To heat a large target volume, multiple treatment spots are required. If the power of each treatment spot is fixed, it could
results in insufficient heating of initial spots and over-heating of later ones, which is caused by the thermal diffusion. Hence, to produce a
uniform heated volume, the delivered energy of each treatment spot
should be properly adjusted. In this study, we proposed an iterative, extrapolation technique to adjust the required ultrasound energy of
each treatment spot. Three different scanning pathways were used to evaluate the performance of this technique. Results indicate that by using the proposed technique, uniform heating volume could be obtained.
Abstract: The area of Project Risk Management (PRM) has
been extensively researched, and the utilization of various tools and
techniques for managing risk in several industries has been
sufficiently reported. Formal and systematic PRM practices have
been made available for the construction industry. Based on such
body of knowledge, this paper tries to find out the global picture of
PRM practices and approaches with the help of a survey to look into
the usage of PRM techniques and diffusion of software tools, their
level of maturity, and their usefulness in the construction sector.
Results show that, despite existing techniques and tools, their usage is
limited: software tools are used only by a minority of respondents
and their cost is one of the largest hurdles in adoption. Finally, the
paper provides some important guidelines for future research
regarding quantitative risk analysis techniques and suggestions for
PRM software tools development and improvement.
Abstract: The dissolution of spherical particles in liquids is analyzed dynamically. Here, we consider the case the dissolution of solute yields a solute-free solid phase in the outer portion of a particle. As dissolution proceeds, the interface between the undissolved solid phase and the solute-free solid phase moves towards the center of the particle. We assume that there exist two resistances for the diffusion of solute molecules: the resistance due to the solute-free portion of the particle and that due to a surface layer near solid-liquid interface. In general, the equation governing the dynamic behavior of dissolution needs to be solved numerically. However, analytical expressions for the temporal variation of the size of the undissoved portion of a particle and the variation of dissolution time can be obtained in some special cases. The present analysis takes the effect of variable bulk solute concentration on dissolution into account.
Abstract: In this paper we study some numerical methods to solve a model one-dimensional convection–diffusion equation. The semi-discretisation of the space variable results into a system of ordinary differential equations and the solution of the latter involves the evaluation of a matrix exponent. Since the calculation of this term is computationally expensive, we study some methods based on Krylov subspace and on Restrictive Taylor series approximation respectively. We also consider the Chebyshev Pseudospectral collocation method to do the spatial discretisation and we present the numerical solution obtained by these methods.
Abstract: The dispersion of heavy particles line in an isotropic
and incompressible three-dimensional turbulent flow has been
studied using the Kinematic Simulation techniques to find out the
evolution of the line fractal dimension. In this study, the fractal
dimension of the line is found for different cases of heavy particles
inertia (different Stokes numbers) in the absence of the particle
gravity with a comparison with the fractal dimension obtained in the
diffusion case of material line at the same Reynolds number. It can
be concluded for the dispersion of heavy particles line in turbulent
flow that the particle inertia affect the fractal dimension of a line
released in a turbulent flow for Stokes numbers 0.02 < St < 2. At the
beginning for small times, most of the different cases are not affected
by the inertia until a certain time, the particle response time τa, with
larger time as the particles inertia increases, the fractal dimension of
the line increases owing to the particles becoming more sensitive to
the small scales which cause the change in the line shape during its
journey.
Abstract: Female breast cancer is the second in frequency after cervical cancer. Surgery is the most common treatment for breast cancer, followed by chemotherapy as a treatment of choice. Although effective, it causes serious side effects. Controlled-release drug delivery is an alternative method to improve the efficacy and safety of the treatment. It can release the dosage of drug between the minimum effect concentration (MEC) and minimum toxic concentration (MTC) within tumor tissue and reduce the damage of normal tissue and the side effect. Because an in vivo experiment of this system can be time-consuming and labor-intensive, a mathematical model is desired to study the effects of important parameters before the experiments are performed. Here, we describe a 3D mathematical model to predict the release of doxorubicin from pluronic gel to treat human breast cancer. This model can, ultimately, be used to effectively design the in vivo experiments.
Abstract: One of research issues in social network analysis is to
evaluate the position/importance of users in social networks. As the
information diffusion in social network is evolving, it seems difficult
to evaluate the importance of users using traditional approaches. In
this paper, we propose an evaluation approach for user importance
with fractal view in social networks. In this approach, the global importance
(Fractal Importance) and the local importance (Topological
Importance) of nodes are considered. The basic idea is that the bigger
the product of fractal importance and topological importance of a
node is, the more important of the node is. We devise the algorithm
called TFRank corresponding to the proposed approach. Finally, we
evaluate TFRank by experiments. Experimental results demonstrate
our TFRank has the high correlations with PageRank algorithm
and potential ranking algorithm, and it shows the effectiveness and
advantages of our approach.
Abstract: In this study, the kinetics of osmotic dehydration of melons (Tille variety) in a ternary system followed by air-drying for preserving melons in the summer to be used in the winter were investigated. The effect of different osmotic solution concentrations 30, 40 and 50% (w/w) of sucrose with 10% NaCl salt and fruit to solution ratios 1:4, 1:5 and 1:6 on the mass transfer kinetics during osmotic dehydration of melon in ternary solution namely sucrosesalt- water followed by air-drying were studied. The diffusivity of water during air-drying was enhanced after the fruit samples were immersed in the osmotic solution after 60 min. Samples non-treated and pre-treated during one hour in osmotic solutions with 60% (w/w) of sucrose with 10% NaCl salt and fruit to solution ratio of 1:4 were dried in a hot air-dryer at 60oC (2 m/s) until equilibrium was achieved.
Abstract: Image interpolation is a common problem in imaging applications. However, most interpolation algorithms in existence suffer visually the effects of blurred edges and jagged artifacts in the image to some extent. This paper presents an adaptive feature preserving bidirectional flow process, where an inverse diffusion is performed to sharpen edges along the normal directions to the isophote lines (edges), while a normal diffusion is done to remove artifacts (“jaggies") along the tangent directions. In order to preserve image features such as edges, corners and textures, the nonlinear diffusion coefficients are locally adjusted according to the directional derivatives of the image. Experimental results on synthetic images and nature images demonstrate that our interpolation algorithm substantially improves the subjective quality of the interpolated images over conventional interpolations.
Abstract: This paper presents a finite point method based on
directional derivatives for diffusion equation on 2D scattered points.
To discretize the diffusion operator at a given point, a six-point stencil
is derived by employing explicit numerical formulae of directional
derivatives, namely, for the point under consideration, only five
neighbor points are involved, the number of which is the smallest for
discretizing diffusion operator with first-order accuracy. A method for
selecting neighbor point set is proposed, which satisfies the solvability
condition of numerical derivatives. Some numerical examples are
performed to show the good performance of the proposed method.
Abstract: In this paper, we develop an accurate and efficient Haar wavelet method for well-known FitzHugh-Nagumo equation. The proposed scheme can be used to a wide class of nonlinear reaction-diffusion equations. The power of this manageable method is confirmed. Moreover the use of Haar wavelets is found to be accurate, simple, fast, flexible, convenient, small computation costs and computationally attractive.
Abstract: In this research, the diffusion of innovation regarding
smartphone usage is analysed through a consumer behaviour theory.
This research aims to determine whether a pattern surrounding the
diffusion of innovation exists. As a methodology, an empirical study
of the switch from a conventional cell phone to a smartphone was
performed. Specifically, a questionnaire survey was completed by
general consumers, and the situational and behavioural characteristics
of switching from a cell phone to a smartphone were analysed. In
conclusion, we found that the speed of the diffusion of innovation, the
consumer behaviour characteristics, and the utilities of the product
vary according to the stage of the product life cycle.
Abstract: A new design of a planar passive T-micromixer with fin-shaped baffles in the mixing channel is presented. The mixing efficiency and the level of pressure loss in the channel have been investigated by numerical simulations in the range of Reynolds number (Re) 1 to 50. A Mixing index (Mi) has been defined to quantify the mixing efficiency, which results over 85% at both ends of the Re range, what demonstrates the micromixer can enhance mixing using the mechanisms of diffusion (lower Re) and convection (higher Re). Three geometric dimensions: radius of baffle, baffles pitch and height of the channel define the design parameters, and the mixing index and pressure loss are the performance parameters used to optimize the micromixer geometry with a multi-criteria optimization method. The Pareto front of designs with the optimum trade-offs, maximum mixing index with minimum pressure loss, is obtained. Experiments for qualitative and quantitative validation have been implemented.
Abstract: Web-based technologies have created numerous
opportunities for electronic word-of-mouth (eWOM) communication.
There are many factors that affect customer adoption and decisionmaking
process. However, only a few researches focus on some
factors such as the membership time of forum and propensity to trust.
Using a discrete-time event simulation to simulate a diffusion model
along with a consumer decision model, the study shows the effect of
each factor on adoption of opinions on on-line discussion forum. The
purpose of this study is to examine the effect of factor affecting
information adoption and decision making process. The model is
constructed to test quantitative aspects of each factor. The simulation
study shows the membership time and the propensity to trust has an
effect on information adoption and purchasing decision. The result of
simulation shows that the longer the membership time in the
communities and the higher propensity to trust could lead to the
higher demand rates because consumers find it easier and faster to
trust the person in the community and then adopt the eWOM. Other
implications for both researchers and practitioners are provided.
Abstract: A large number of chemical, bio-chemical and pollution-control processes use heterogeneous fixed-bed reactors. The use of finite hollow cylindrical catalyst pellets can enhance conversion levels in such reactors. The absence of the pellet core can significantly lower the diffusional resistance associated with the solid phase. This leads to a better utilization of the catalytic material, which is reflected in the higher values for the effectiveness factor, leading ultimately to an enhanced conversion level in the reactor. It is however important to develop a rigorous heterogeneous model for the reactor incorporating the two-dimensional feature of the solid phase owing to the presence of the finite hollow cylindrical catalyst pellet. Presently, heterogeneous models reported in the literature invariably employ one-dimension solid phase models meant for spherical catalyst pellets. The objective of the paper is to present a rigorous model of the fixed-bed reactors containing finite hollow cylindrical catalyst pellets. The reaction kinetics considered here is the widely used Michaelis–Menten kinetics for the liquid-phase bio-chemical reactions. The reaction parameters used here are for the enzymatic degradation of urea. Results indicate that increasing the height to diameter ratio helps to improve the conversion level. On the other hand, decreasing the thickness is apparently not as effective. This could however be explained in terms of the higher void fraction of the bed that causes a smaller amount of the solid phase to be packed in the fixed-bed bio-chemical reactor.