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Miklavcic, Stan J.
Alternative names
Publications (10 of 26) Show all publications
Bradshaw-Hajek, B. H., Miklavcic, S. & Ward, D. A. (2013). A composite Level Set and Extended-Domain-Eigenfunction Method for simulating 2D Stokes flow involving a free surface. Journal of Computational and Applied Mathematics, 237(1), 389-402
Open this publication in new window or tab >>A composite Level Set and Extended-Domain-Eigenfunction Method for simulating 2D Stokes flow involving a free surface
2013 (English)In: Journal of Computational and Applied Mathematics, ISSN 0377-0427, E-ISSN 1879-1778, Vol. 237, no 1, p. 389-402Article in journal (Refereed) Published
Abstract [en]

In this paper, the Extended-Domain-Eigenfunction-Method (EDEM) is combined with the Level Set Method in a composite numerical scheme for simulating a moving boundary problem. The liquid velocity is obtained by formulating the problem in terms of the EDEM methodology and solved using a least square approach. The propagation of the free surface is effected by a narrow band Level Set Method. The two methods both pass information to each other via a bridging process, which allows the position of the interface to be updated. The numerical scheme is applied to a series of problems involving a gas bubble submerged in a viscous liquid moving subject to both an externally generated flow and the influence of surface tension.

Place, publisher, year, edition, pages
Elsevier, 2013
Keywords
BVPs, Elliptic operators, EDEM, Stokes equation, Level Set Method, Free boundary problem
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-85623 (URN)10.1016/j.cam.2012.06.009 (DOI)000309847100033 ()
Note

Funding Agencies|Swedish Research Council||Australian Postgraduate Award||

Available from: 2012-11-26 Created: 2012-11-26 Last updated: 2017-12-07
Aarao, J., Miklavcic, S. J. & Ward, D. A. (2013). Extended-domain-eigenfunction method (EDEM): a study of ill posedness and regularization. Journal of Physics A: Mathematical and Theoretical, 46(8)
Open this publication in new window or tab >>Extended-domain-eigenfunction method (EDEM): a study of ill posedness and regularization
2013 (English)In: Journal of Physics A: Mathematical and Theoretical, ISSN 1751-8113, E-ISSN 1751-8121, Vol. 46, no 8Article in journal (Refereed) Published
Abstract [en]

The extended-domain-eigenfunction method (EDEM) proposed for solving elliptic boundary value problems on annular-like domains requires an inversion process. The procedure thus represents an ill-posed problem, whose numerical solution involves an ill-conditioned system of equations. In this paper, the ill-posed nature of EDEM is studied and numerical solutions based on regularization schemes are considered. It is shown that the EDEM solution methodology lends itself naturally to a formulation in terms of the well-known iterative Landweber method and the more general and faster converging semi-iterative regularization schemes. Theoretical details and numerical results of the regularization schemes are presented for the case of the two-dimensional Laplace operator on annular domains.

Place, publisher, year, edition, pages
Institute of Physics, 2013
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-89796 (URN)10.1088/1751-8113/46/8/085207 (DOI)000314821900010 ()
Note

Funding Agencies|Swedish Research Council||Australian Postgraduate Award||

Available from: 2013-03-07 Created: 2013-03-07 Last updated: 2017-12-06
Aarao, J., Bradshaw-Hajek, B. H., Miklavcic, S. & Ward, D. A. (2011). Numerical implementation of the EDEM for modified Helmholtz BVPs on annular domains. JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS, 235(5), 1342-1353
Open this publication in new window or tab >>Numerical implementation of the EDEM for modified Helmholtz BVPs on annular domains
2011 (English)In: JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS, ISSN 0377-0427, Vol. 235, no 5, p. 1342-1353Article in journal (Refereed) Published
Abstract [en]

In a recent paper by the current authors a new methodology called the Extended-Domain-Eigenfunction-Method (EDEM) was proposed for solving elliptic boundary value problems on annular-like domains. In this paper we present and investigate one possible numerical algorithm to implement the EDEM. This algorithm is used to solve modified Helmholtz BVPs on annular-like domains. Two examples of annular-like domains are studied. The results and performance are compared with those of the well-known boundary element method (BEM). The high accuracy of the EDEM solutions and the superior efficiency of the EDEM over the BEM, make EDEM an excellent alternate candidate to use in the animation industry, where speed is a predominant requirement, and by the scientific community where accuracy is the paramount objective.

Place, publisher, year, edition, pages
Elsevier Science B.V., Amsterdam., 2011
Keywords
BVPs, Elliptic operators, EDEM, Modified Helmholtz equation, BEM, Trefftz method
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-63393 (URN)10.1016/j.cam.2010.08.022 (DOI)000284389700021 ()
Available from: 2010-12-17 Created: 2010-12-17 Last updated: 2010-12-17
Bradshaw-Hajek, B. H., Miklavcic, S. & White, L. R. (2010). The Actual Dielectric Response Function for a Colloidal Suspension of Spherical Particles. LANGMUIR, 26(11), 7875-7884
Open this publication in new window or tab >>The Actual Dielectric Response Function for a Colloidal Suspension of Spherical Particles
2010 (English)In: LANGMUIR, ISSN 0743-7463, Vol. 26, no 11, p. 7875-7884Article in journal (Refereed) Published
Abstract [en]

In this paper, we present a theoretical analysis of the dielectric response of a dense suspension of spherical colloidal particles based on a self-consistent cell model. Particular attention is paid to (a) the relationship between the dielectric response and the conductivity response and (b) the connection between the real and imaginary parts of these responses based on the Kramers-Kronig relations. We have thus clarified the analysis of Carrique et al. (Carrique, F. Criado, C.; Delgado, A. V. J. Colloid Interface Sci. 1993, 156, 117). We have shown that both the conduction and displacement current components are complex quantities with both real and imaginary parts being frequency dependent. The dielectric response exhibits characteristics of two relaxation phenomena: the Maxwell-Wagner and the a-relaxations, with the imaginary part being the more sensitive instrument. The inverse Fourier transform of the simulated dielectric response is compared with a phenomenological, two-exponential response function with good agreement obtained. The two fitted decay times also compare well with times extracted from the explicit simulations.

Place, publisher, year, edition, pages
ACS American Chemical Society, 2010
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-57168 (URN)10.1021/la904767p (DOI)000277928100034 ()
Available from: 2010-06-11 Created: 2010-06-11 Last updated: 2010-06-11
Aarao, J., Bradshaw-Hajek, B. H., Miklavcic, S. & Ward, D. A. (2010). The extended-domain-eigenfunction method for solving elliptic boundary value problems with annular domains. JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL, 43(18), 185202
Open this publication in new window or tab >>The extended-domain-eigenfunction method for solving elliptic boundary value problems with annular domains
2010 (English)In: JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL, ISSN 1751-8113, Vol. 43, no 18, p. 185202-Article in journal (Refereed) Published
Abstract [en]

Standard analytical solutions to elliptic boundary value problems on asymmetric domains are rarely, if ever, obtainable. In this paper, we propose a solution technique wherein we embed the original domain into one with simple boundaries where the classical eigenfunction solution approach can be used. The solution in the larger domain, when restricted to the original domain, is then the solution of the original boundary value problem. We call this the extended-domain-eigenfunction method. To illustrate the methods strength and scope, we apply it to Laplaces equation on an annular-like domain.

Place, publisher, year, edition, pages
Iop, 2010
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-55520 (URN)10.1088/1751-8113/43/18/185202 (DOI)000276838600007 ()
Available from: 2010-04-30 Created: 2010-04-30 Last updated: 2010-04-30
Bradshaw-Hajek, B. H., Miklavcic, S. J. & White, L. R. (2009). Dynamic Dielectric Response of Concentrated Colloidal Dispersions: Comparison between Theory and Experiment. Langmuir, 25(4), 1961-1969
Open this publication in new window or tab >>Dynamic Dielectric Response of Concentrated Colloidal Dispersions: Comparison between Theory and Experiment
2009 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 25, no 4, p. 1961-1969Article in journal (Refereed) Published
Abstract [en]

The cell-model electrokinetic theory of Ahualli et al. Langmuir 2006, 22, 704 1; Ahualli et al. J. Colloid Interface Sci. 2007, 309, 342; and Bradshaw-Hajek et al. Langmuir 2008, 24, 4512 is applied to a dense suspension of charged spherical particles, to exhibit the systems dielectric response to an applied electric field as a function of solids volume fraction. The models predictions of effective permittivity and complex conductivity are favorably compared with published theoretical calculations and experimental measurements on dense colloidal systems. Physical factors governing the volume fraction dependence of the dielectric response are discussed.

Place, publisher, year, edition, pages
ACS American Chemical Society, 2009
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-55095 (URN)10.1021/la8028963 (DOI)000263373600017 ()
Available from: 2010-04-29 Created: 2010-04-29 Last updated: 2017-12-12
Bradshaw-Hajek, B., Miklavcic, S. & Whitet, L. (2008). Frequency-dependent electrical conductivity of concentrated dispersions of spherical colloidal particles. Langmuir, 24(9), 4512-4522
Open this publication in new window or tab >>Frequency-dependent electrical conductivity of concentrated dispersions of spherical colloidal particles
2008 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 24, no 9, p. 4512-4522Article in journal (Refereed) Published
Abstract [en]

This paper outlines the application of a self-consistent cell-model theory of electrokinetics to the problem of determining the electrical conductivity of a dense suspension of spherical colloidal particles. Numerical solutions of the standard electrokinetic equations, subject to self-consistent boundary conditions, are implemented in formulas for the electrical conductivity appropriate to the particle-averaged cell model of the suspension. Results of calculations as a function of frequency, zeta potential, volume fraction, and electrolyte composition, are presented and discussed. © 2008 American Chemical Society.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-46155 (URN)10.1021/la703777g (DOI)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-13
Ahualli, S., Delgado, A., Miklavcic, S. & White, L. (2007). Use of a cell model for the evaluation of the dynamic mobility of spherical silica suspensions. Journal of Colloid and Interface Science, 309(2), 342-349
Open this publication in new window or tab >>Use of a cell model for the evaluation of the dynamic mobility of spherical silica suspensions
2007 (English)In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 309, no 2, p. 342-349Article in journal (Refereed) Published
Abstract [en]

In this paper we evaluate the validity of a cell model for the calculation of the dynamic mobility of concentrated suspensions of spheres. The key point is the consideration of the boundary conditions (electrical and hydrodynamic) at the boundary of the fluid cell surrounding a single probe particle. The model proposed is based on a universal criterion for the averages of fluid velocity, electric potential, pressure field or electrochemical properties in the cell. The calculations are checked against a wide set of experimental data on the dynamic mobility of silica suspensions with two different radii, several ionic strengths, and two particle concentrations. The comparison reveals an excellent agreement between theory and experiment, and the model appears to be extremely suitable for correctly predicting the behavior of the dynamic mobility, including the changes in the zeta potential, ?, with ionic strength, the frequency and amplitude of the Maxwell-Wagner-O'Konski relaxation, and the inertial relaxation occurring at the top of the frequency range accessible to our experimental device. © 2007 Elsevier Inc. All rights reserved.

Keywords
Concentrated suspensions, Dynamic mobility, Electroacoustic methods, Electrokinetic cell models, Silica particles
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-49732 (URN)10.1016/j.jcis.2007.02.006 (DOI)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-12
Ahualli, S., Delgado, A., Miklavcic, S. & White, L. (2006). Dynamic electrophoretic mobility of concentrated dispersions of spherical colloidal particles. On the consistent use of the cell model. Langmuir, 22(16), 7041-7051
Open this publication in new window or tab >>Dynamic electrophoretic mobility of concentrated dispersions of spherical colloidal particles. On the consistent use of the cell model
2006 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 22, no 16, p. 7041-7051Article in journal (Refereed) Published
Abstract [en]

This paper outlines a complete and self-consistent cell model theory of the electrokinetics of dense spherical colloidal suspensions for general electrolyte composition, frequency of applied field, ? potential, and particle size. The standard electrokinetic equations, first introduced for any given particle configuration, are made tractable to computation by averaging over particle configurations. The focus of this paper is on the systematic development of suitable boundary conditions at the outer cell boundary obtained from global constraints on the suspension. The approach is discussed in relation to previously published boundary conditions that have often been introduced in an ad hoc manner. Results of a robust numerical calculation of high-frequency colloidal transport properties, such as dynamic mobility, using the present model are presented and compared with some existing dense suspension models. © 2006 American Chemical Society.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-50173 (URN)10.1021/la0607252 (DOI)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-12
Miklavcic, S. J. & Said, E. (2006). Electrostatic potential and double layer force in a semiconductor-electrolyte-semiconductor heterojunction. Physical Review E. Statistical, Nonlinear, and Soft Matter Physics: Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, 74(6), 061606-
Open this publication in new window or tab >>Electrostatic potential and double layer force in a semiconductor-electrolyte-semiconductor heterojunction
2006 (English)In: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics: Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, ISSN 1063-651X, E-ISSN 1095-3787, Vol. 74, no 6, p. 061606-Article in journal (Refereed) Published
Abstract [en]

This paper reports a theoretical study of the electrostatic potential within a so-called pen-heterojunction made up of two semi-infinite, doped semiconductor media separated by an electrolyte region. An external potential is then applied across the entire system. Both the electrostatic potentials and double layer surface forces are studied as functions of the usual double layer system properties, semiconductor properties such as doping concentrations of acceptor and donator atoms, as well as applied potential. We find that both attractive and repulsive forces are possible depending on the surface charges on the electrolyte-semiconductor interfaces, and that these forces can be significantly modified by the applied potential and by the doping levels in the semiconductors.

Keywords
electrolytes; semiconductor heterojunctions; semiconductor doping; doping profiles; interface phenomena
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:liu:diva-15727 (URN)10.1103/PhysRevE.74.061606 (DOI)
Available from: 2008-12-04 Created: 2008-12-01 Last updated: 2017-12-14Bibliographically approved
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