bluuebunny/crossref_metadata_2025_split huggingface dataset:
Virulence modulation of Streptococcus mutans biofilms by metal ions released from orthodontic appliances
Authors: Rymovicz Alinne Ulbrich Mores , Ronsani Maiara Medeiros , Grégio Ana Maria Trindade , Guariza-Filho Odilon Guariza , Tanaka Orlando , Rosa Edvaldo Antonio Ribeiro 
Published: April 2013

ABSTRACT

Objectives:
To evaluate the impact of metal ions commonly shed from orthodontic appliances on the virulence of Streptococcus mutans ATCC®25175™ biofilms.

Materials and Methods:
Biofilms were grown in the presence of Ni2+, Fe3+, Cr3+, Co2+, and a metal ion pool at concentrations similar to those released in saliva of orthodontic patients for 72 hours. Once mature, biofilms were treated for up to 12 hours with 5% glucose.

Results:
Ions interfered with the growth of S mutans by reducing its biomass (Ni2+, Fe3+, Cr3+), raising its rates of sugar metabolism (Ni2+, Fe3+, Cr3+), and raising its secretion of lactate (Ni2+, Fe3+, Cr3+, pool).

Conclusion:
The laboratory data presented here point to the possibility of virulence increase of S mutans by metal ions commonly released during orthodontic therapy.
Accuracy of Ceramic Mould Filling with Liquid AlSi9 Aluminium Alloy in the Process Using Back-Pressure
Authors: Karwiński A. , Haratym R. , Biernacki R. 
Published: April 2013

Abstract
The paper presents the effect of suction pressure exerted on the liquid AlSi alloy when it is introduced into a ceramic mould made in the investment process and the results compared with data obtained on gravity poured castings. The study used special pattern sets and ceramic moulds made with the alternately applied soluble silicate binder and ethyl silicate. Additionally, self-supported moulds based entirely on the Ekosil binder were used. In the analysis of castings, the following parameters were examined: a linear dimensional accuracy, the state of surface microgeometry and the possibility of metal penetration into a complex ceramic mould, allowing also for the presence of capillary phenomena. In the process of casting with back-pressure, the pressure values of 500 hPa, 600 hPa and 700 hPa were applied in the chamber where the ceramic mould was located, with the temperature of the said mould kept at a level of 150 ± 10°C.
Microstructural Characterization of Cast Magnesium Matrix Composites by Raman Microscopy
Authors: Malika M.A. , Majchrzak K. , Braszczyńska-Malik K.N. 
Published: April 2013

Abstract
Cast magnesium matrix composites reinforced with silicon carbide particles were investigated by using Raman microscopy. 3C, 4H and 6H polytypes of SiC particles were identified in the investigated composites. Additionally, Mg2Si compound was detected by Raman microscopy in the composites microstructure.
Composite Zones Produced in Situ in the Ni3Al Phase
Authors: Olejnika E. , Janas A. , Sikora G. , Tokarski T. , Nowak J. 
Published: April 2013

Abstract
The study presents the results of research on the development of composite zones in castings based on the intermetallic phase of Ni3Al. Composite zones were obtained by placing packets with substrates for the reaction of titanium carbide in a foundry mould. To provide a variable carbides content in the composite zone, two compositions of the packets were prepared. The first packet contained only substrates for the reaction of TiC synthesis; the second one also contained a filler. The resulting composite zones in castings were examined for the filler effect on changes in the volume fraction, size and morphology of carbides in the zone. In addition, the effect of filler on the mechanical properties of the zone was verified, observing changes of Vickers hardness in this area. It was found that the presence of filler in the composition of the packet for synthesis reduced the content of carbides, as well as their size and morphology. Lower surface content of carbides reduced hardness of the zone, which enabled smooth control of the mechanical properties. At the same time, the use of the selected filler did not disturb the course of the TiC carbide synthesis.
The Influence of Silica Module of the Soluble Sodium Silicate Hardened by Ester on the Residual Strenght of Molding Sand
Authors: Baliński A. 
Published: April 2013

Abstract
Describes how to obtain a soluble sodium silicate with a density of 1.40 g/cm3, 1.45 g/cm3, 1.50 g/cm3, and silica module M = 2.1 obtained from the silica- sodium glass with module M = 3.3 and M = 2.1. Residual (final) strength of molding samples made with these binders, were determined at temperatures corresponding to the characteristic temperatures of phase and temperature transitions of silica gel. Indicated the type of soluble sodium silicate capable of obtain the smallest value of the final strength of molding sand in the specified range of temperatures.
Individual Recognition from Gait Using Feature Value Method
Authors: Zhang Tianxiang , Venture Gentiane 
Published: April 2013

Abstract
We propose a novel framework to recognize individuals from gait, in order to improve HRI. We collected the motion data of the torso from 13 persons’ gait, using 2 IMU sensors. We developed Feature Value Method which is a PCA based classifier and we achieved an average individual recognition rate of 94% through cross-validation.
New Reference-Neighbourhood Scalarization Problem for Multiobjective Integer Programming
Authors: Genova Krasimira , Kirilov Leonid , Guljashki Vasil 
Published: April 2013

Abstract
Scalarization is a frequently used approach for finding efficient solutions that satisfy the preferences of the Decision Maker (DM) in multicriteria optimization. The applicability of a scalarization problem to solve integer multicriteria problems depends on the possibilities it provides for the decrease of the computing complexity in finding optimal solutions of this class of problems. This paper presents a reference-neighbourhood scalarizing problem, possessing properties that make it particularly suitable for solving integer problems. One of the aims set in this development has also been the faster obtaining of desired criteria values, defined by the DM, requiring no additional information by him/her. An illustrative example demonstrates the features of this scalarizing problem.
Pointwise a Posteriori Error Analysis for an Adaptive Penalty Finite Element Method for the Obstacle Problem
Authors: French Donald A. , Larsson Stig , Nochetto Ricardo H. 
Published: April 2013

Abstract Finite element approximations based on a penalty formulation of the
elliptic obstacle problem are analyzed in the maximum norm. A posteriori error estimates,
which involve a residual of the approximation and a spatially variable penalty
parameter, are derived in the cases of both smooth and rough obstacles. An adaptive
algorithm is suggested and implemented in one dimension.
The Finite Difference Scheme for 3d Mathematical Modeling of a Wood Drying Process
Authors: Čiegis Raimondas , Starikovičius Vadimas 
Published: April 2013

AbstractThis work discusses issues on the design and analysis of finite difference
schemes for 3D modeling the process of moisture motion in the wood. A new finite
difference scheme is proposed. The stability and convergence in the maximum norm
are proved for Robin boundary conditions. The influence of boundary conditions is
investigated, and results of numerical experiments are presented.
Fractional Order Convergence Rate Estimates Of Finite Difference Method On Nonuniform Meshes
Authors: Bojović Dejan , Jovanović Boško 
Published: April 2013

AbstractIn this paper we show how the theory of interpolation of function
spaces can be used to establish convergence rate estimates for finite difference schemes
on nonuniform meshes. As a model problem we consider the first boundary value
problem for the Poisson equation. Using the interpolation theory we construct a
fractional-order convergence rate estimate which is consistent with the smoothness of
data.
The Maximum Principle and Some of Its Applications
Authors: Matus Piotr 
Published: April 2013

AbstractThe subject of this paper is the maximum principle and its application
for investigating the stability and convergence of finite difference schemes. To
some extent, this is a survey of the works on constructing and investigating certain
new classes of monotone difference schemes. In this connection the maximum principle
for the derivatives discussed in this paper is of fundamental importance. It is
used as a basis for proving the coefficient stability of difference schemes in Banach
spaces and the monotonicity of economical schemes of full approximation. New results
on unconditional stability of monotone difference schemes with weights, conservative
explicit-implicit schemes (staggered schemes), monotone schemes of second-order approximation
in arbitrary domains, and monotone difference schemes for multidimensional
elliptic equations with mixed derivatives are given.
On the Stability of Differential-operator Equations and Operator-difference Schemes as t → ∞
Authors: Jovanović Boško , Lemeshevsky Sergey , Matus Peter 
Published: April 2013

Abstract
For the abstract Cauchy problem for a parabolic equation a priori
estimates of the global and asymptotic stability in various energy norms have been
obtained. Similar problems are also considered for the second-order equation. In the
latter case, a priori estimates of the asymptotic stability by the initial data have been
obtained. The corresponding estimates of the global stability for three-level operator
difference schemes have been proved. Estimates of the asymptotic behavior of
the solution for quasi-linear multidimensional equations with unbounded nonlinearity
have been obtained. The corresponding mathematical apparatus permitting one to
prove unconditional monotonicity of the difference schemes approximating nonlinear
problems is presented.
The Two-sided FD-method of Solving the First Boundary Problem for Singular ODE of the Second Order in the Half-axis
Authors: Makarov V.L. , Lazurchak I.I. 
Published: April 2013

AbstractTo solve the boundary problems for singular ordinary differential equations
of the second order the functional-discrete (FD-) method is proposed. The method
gives the possibility of obtaining an approximate solution in the numerical-analytical
form in the whole half-axis with a guaranteed accuracy. Sufficient conditions of convergence
of the method at a rate of a geometrical progression are found. The two-sided
approximations are established and an explicit evaluation of the two-sided estimation
width is given. In conclusion the results of numerical experiments obtained by the
system of computer algebra are presented.
Non-conforming Computational Methods for Mixed Elasticity Problems
Authors: Belgacem Faker Ben , Chilton Lawrence K. , Seshaiyer Padmanabhan 
Published: April 2013

AbstractIn this paper, we present a non-conforming hp computational modeling methodology
for solving elasticity problems. We consider the incompressible elasticity model
formulated as a mixed displacement-pressure problem on a global domain which is
partitioned into several local subdomains. The approximation within each local
subdomain is designed using div-stable hp-mixed finite elements. The displacement
is computed in a mortared space while the pressure is not subjected to any constraints
across the interfaces. Our computational results demonstrate that the non-conforming
finite element method presented for the elasticity problem satisfies similar rates of
convergence as the conforming finite element method, in the presence of various h-version and p-version discretizations.
On a Nonlocal Boundary-value Problem for Two-dimensional Elliptic Equation
Authors: Berikelashvili Givi , Ionkin Nikolai I. , Morozova Valentina A. 
Published: April 2013

AbstractA boundary-value problem with a nonlocal integral condition is considered for a two-dimensional elliptic
equation with constant coefficients and a mixed derivative. The existence and uniqueness of a weak solution
of this problem are proved in a weighted Sobolev space. A difference scheme is constructed using the Steklov averaging operators.
A Parallel High-accuracy Method for the First-order Evolution Equation in Hilbert and Banach Spaces
Authors: Garvrilyuk Ivan P. , Makarov Vladimir L. , Ryabichev Vyacheslav L. 
Published: April 2013

AbstractWe have developed a discretization method of an arbitrarily given order of accuracy with respect to the time discretization parameter for the first-order
evolution differential equation in Banach space. The method includes two levels of parallelism: the operator exponential needed for the calculation of the evolution operator
can be computed in parallel (inner parallelism) and then we can compute in parallel the evolution operator at various points of the time mesh (outer
parallelism).
Accuracy Estimates of Difference Schemes for Quasi-linear Parabolic Equations Taking into Account the Initial-boundary Effect
Authors: Makarov V. L. , Demkiv L. I. 
Published: April 2013

AbstractFor difference schemes the initial-boundary problem for quasi-linear parabolic-type equations, ’a priori weight estimates’ of the error have been found. These estimates show how much the accuracy of difference schemes near the boundary of a time rectangle is higher than in the middle of it. Sufficient conditions of smoothness of the coefficients and the right-hand side of the quasi-linear parabolic equation and the initial conditions have been found. These conditions ensure a correctness of these a priori estimates.
Numerical Study of Steady Flow Past a Sphere in an Aligned Magnetic Field
Authors: Sekhar T.V.S. , Sivakumar R. , Kumar Harish 
Published: April 2013

AbstractThe ﬂow of a steady, incompressible, viscous, electrically conducting
ﬂuid past a sphere in the presence of uniform magnetic ﬁeld parallel to the undisturbed
ﬂow is investigated using the ﬁnite difference method. The multigrid method with a
defect correction (DC) technique is used to achieve the second order accurate solution.
The Hartmann number M is used as the perturbation parameter. It has been found
that the increase of magnetic ﬁeld decreases the wake length (L) and increases the drag
coefficient. The graphs of streamlines, vorticity lines, drag coefficient, wake length,
surface pressure and surface vorticity are presented and discussed
A Generalized Relaxation Method for Transport and Diffusion of Pollutant Models in Shallow Water
Authors: Delis A.I. , Katsaounis Th. 
Published: April 2013

AbstractWe present a numerical method based on finite difference relaxation
approximations for computing the transport and diffusion of a passive pollutant by a
water flow. The flow is modeled by the well-known shallow water equations and the
pollutant propagation is described by a transport equation. The previously developed
nonoscillatory relaxation scheme is generalized to cover problems with pollutant trans-
port, in one and two dimensions and source terms, resulting in a class of methods of
the first and the second order of accuracy in space and time. The methods are based on
the classical relaxation models combined with a Runge-Kutta time splitting scheme,
where neither Riemann solvers nor characteristic decompositions are needed. Numerical
results are presented for several benchmark test problems. The schemes presented
are verified by comparing the results with documented ones, proving that no special
treatment is needed for the transport equation in order to obtain accurate results.
Error Estimates and Iterative Procedure for Mixed Finite Element Solution of Second-Order Quasi-Linear Elliptic Problems
Authors: Karchevsky Mikhail , Fedotov Alexander 
Published: April 2013

AbstractThe mixed finite element method for second-order quasi-linear elliptic
equations with nonlinearities of arbitrary power rate of growth is considered. Error
estimates are obtained. An iterative method for corresponding discrete problem is
proposed and investigated.
Instability and Collapse in Discrete Wave Equations
Authors: Carpio A. , Duro G. 
Published: April 2013

AbstractUnstable growth phenomena in spatially discrete wave equations are
studied. We characterize sets of initial states leading to instability and collapse and
obtain analytical predictions for the blow-up time. The theoretical predictions are con-
trasted with the numerical solutions computed by a variety of schemes. The behavior
of the systems in the continuum limit and the impact of discreteness and friction are
discussed.
Stability Criterion of Difference Schemes for the Heat Conduction Equation with Nonlocal Boundary Conditions
Authors: Gulin A. , Ionkin N. , Morozova V. 
Published: April 2013

Abstract The elements of the stability theory of nonselfadoint difference schemes
for nonstationary problems of mathematical physics are discussed. Difference schemes
for the heat conduction equation with nonlocal boundary conditions are considered in
detail from the viewpoint of the general stability theory of two-layer operator-difference
schemes. The necessary and sufficient stability conditions in the sense of the initial data
in special energy norm have been found. The equivalence of the energy norm to the
grid L2-norm has been proved. A priori estimates expressing the difference schemes
stability in the sense of the right-hand side have been constructed.
On Finite Volume Discretization of the Three-dimensional Biot Poroelasticity System in Multilayer Domains
Authors: Naumovich A. 
Published: April 2013

AbstractIn this paper we propose a finite volume discretization for the threedimensional
Biot poroelasticity system in multilayer domains. For stability reasons,
staggered grids are used. The discretization takes into account discontinuity of the
coefficients across the interfaces between layers with different physical properties. Numerical
experiments based on the proposed discretization showed second order convergence
in the maximum norm for the primary and flux unknowns of the system. An
application example is presented as well.
Sparse Radiographic Tomography and System Identification Imaging from Single View, Multiple Time Sample Density Plots
Authors: Asaki T.J. , Bollt E.M. , Vixie K.R. 
Published: April 2013

Abstract Tomography is a classic inverse problem in which multiple density
projections of an object are processed to infer some approximation of the original. We
consider the highly sparse inverse problem of single angle projection, but seek to reduce
the ambiguity through multiple time observations in a dynamic system of known or
partially known dynamics. In this work we solve the planar problem by optimization
techniques based on a gradient-free multi-directional search algorithm to minimize our
nonlinear functional. We demonstrate convincingly successful numerical examples to
support our relatively simple technique.
Fedorenko Finite Superelement Method and Its Applications
Authors: Galanin M. , Lazareva S. , Savenkov E. 
Published: April 2013

AbstractThis paper considers the Fedorenko Finite Superelement Method
(FSEM) and some of its applications. The general idea, the main theoretical background,
and the results of the numerical investigation of the method are presented
using the model problem for the Laplace equation. Generalization to some other problems
using the general approach suggested by the authors is also considered.
A Weighted Residual Parabolic Acceleration Time Integration Method for Problems in Structural Dynamics
Authors: Razavi S.H. , Abolmaali A. , Ghassemieh M. 
Published: April 2013

AbstractIn the proposed method, the variation of displacement in each time step
is assumed to be a fourth order polynomial in time and its five unknown coefficients are
calculated based on: two initial conditions from the previous time step; satisfying the
equation of motion at both ends of the time step; and the zero weighted residual within
the time step. This method is non-dissipative and its dispersion is considerably less
than in other popular methods. The stability of the method shows that the critical time
step is more than twice of that for the linear acceleration method and its convergence
is of fourth order.
Exact Difference Schemes for Hyperbolic Equations
Authors: Matus P. , Kołodyńska A. 
Published: April 2013

AbstractIn the present paper, an exact difference scheme for the initial boundary-
value problem of the third kind for an inhomogeneous hyperbolic equation of the second
order with constant coefficients has been constructed on ordinary rectangular grids with
constant space and time steps, where the Courant number
γ=1. Later we proved a priori estimates of the stability in energy norm. For a quasi-linear wave
equation on the moving characteristic grid a difference scheme has been constructed,
which has the second order of approximation for the initial boundary-value problem
and is exact for the Cauchy problem. The computational results for smooth functions
and for a weak solution confirm the high accuracy of the introduced algorithm. We
have also constructed exact difference schemes for the Cauchy problem for a system
of two hyperbolic equations of the first order with constant coefficients on grids with
constant space and time steps. Stability in energy norm for one
of the constructed schemes has been proved. Using a method analogous to that used
for the nonlinear wave equation a difference scheme for a nonlinear gas dynamic system
has been constructed.
Sharp Expressions for the Stabilization Parameters in Symmetric Interior-penalty Discontinuous Galerkin Finite Element Approximations of Fourth-order Elliptic Problems
Authors: Mozolevski I. , Bösing P.R. 
Published: April 2013

Abstract In this paper, we derive explicit expressions for the penalty parameters
appearing in symmetric and semi-symmetric interior-penalty discontinuous Galerkin
finite element method (DGFEM) for fourth-order elliptic problems. We demonstrate
the sharpness of the theoretically predicted penalty parameter values through numerical
experiments.
An hp-adaptive strategy for the solution Of the exact kernel curved wire pocklington Equation
Authors: HEMKER P.W. , LAHAYE D.J.P. 
Published: April 2013

Abstract
In this paper we introduce an adaptive method for the numerical solu-tion of the Pocklington integro-differential equation with exact kernel for the current induced in a smoothly curved thin wire antenna. The hp-adaptive technique is based on the representation of the discrete solution, which is expanded in a piecewise p-hierarchical basis. The key element in the strategy is an element-by-element criterion that controls the h- or p-refinement. Numerical results demonstrate both the simplicity and efficiency of the approach
Fully Discrete Galerkin Method For Fredholm Integro-Differential Equations With Weakly Singular Kernels
Authors: PEDAS A. , TAMME E. 
Published: April 2013

Abstract Approximations to a solution and its derivatives of a boundary value problem of an nth order linear Fredholm integro-differential equation with weakly sin-gular or other nonsmooth kernels have been determined. These approximations are piecewise polynomial functions on special graded grids. To find them, a fully discrete version of the Galerkin method has been constructed. This version is based on a dis-crete inner product concept and some suitable product integration techniques. Optimal global convergence estimates have been derived and a collection of numerical results of a test problem is given.