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##### Publications (10 of 87) Show all publications
Ijioma, E. R. & Muntean, A. (2019). Fast Drift Effects In The Averaging Of A Filtration Combustion System: A Periodic Homogenization Approach. Quarterly of Applied Mathematics, 77(1), 71-104
Open this publication in new window or tab >>Fast Drift Effects In The Averaging Of A Filtration Combustion System: A Periodic Homogenization Approach
2019 (English)In: Quarterly of Applied Mathematics, ISSN 0033-569X, E-ISSN 1552-4485, Vol. 77, no 1, p. 71-104Article in journal (Refereed) Published
##### Abstract [en]

We target the periodic homogenization of a semi-linear reaction-diffusion-convection system describing filtration combustion, where fast drifts are triggered by the competition between heat and mass transfer processes in an asymptotic regime of dominant convection. In addition, we consider the interplay between surface nonlinear chemical reactions and transport processes. To handle the oscillations occurring due to the heterogeneity of the medium, we rely on the concept of two-scale convergence with drift to obtain, for suitably scaled model parameters, the upscaled system of equations together with effective transport parameters. The main difficulty is to treat the case of a coupled multi-physics problem. We proceed by extending the results reported by G. Allaire et al. and other related papers in this context to the case of a coupled system of evolution equations pertinent to filtration combustion.

##### Place, publisher, year, edition, pages
Brown University Boston, 2019
Mathematics
Mathematics
##### Identifiers
urn:nbn:se:kau:diva-70322 (URN)10.1090/qam/1509 (DOI)000449518100003 ()
Available from: 2018-11-29 Created: 2018-11-29 Last updated: 2019-03-14Bibliographically approved
Kruschwitz, J., Lind, M., Muntean, A., Richardson, O. & Wondmagegne, Y. (2019). Modelling, simulation and parameter identification of active pollution reduction with photocatalytic asphalt. Acta Polytechnica, 59(1), 51-58
Open this publication in new window or tab >>Modelling, simulation and parameter identification of active pollution reduction with photocatalytic asphalt
2019 (English)In: Acta Polytechnica, ISSN 1210-2709, E-ISSN 1805-2363, Vol. 59, no 1, p. 51-58Article in journal (Refereed) Published
##### Abstract [en]

We develop and implement a numerical model to simulate the effect of photocatalytic asphalt on reducing the concentration of nitrogen monoxide (NO) due to the presence of heavy traffic in an urban environment. The contributions in this paper are threefold: we model and simulate the spread and breakdown of pollution in an urban environment, we provide a parameter estimation process that can be used to find missing parameters, and finally, we train and compare this simulation with different data sets. We analyse the results and provide an outlook on further research.

##### Place, publisher, year, edition, pages
Prague: Czech Technical University in Prague, 2019
##### Keywords
Pollution, environmental modelling, parameter identification, finite element simulation
Mathematics
Mathematics
##### Identifiers
urn:nbn:se:kau:diva-70796 (URN)10.14311/AP.2019.59.0051 (DOI)000462321600006 ()
Available from: 2019-01-24 Created: 2019-01-24 Last updated: 2019-04-11Bibliographically approved
Vromans, A., Muntean, A. & van de Ven, F. (2018). A mixture theory-based concrete corrosion model coupling chemical reactions, diffusion and mechanics. PACIFIC JOURNAL OF MATHEMATICS FOR INDUSTRY, 10, Article ID 5.
Open this publication in new window or tab >>A mixture theory-based concrete corrosion model coupling chemical reactions, diffusion and mechanics
2018 (English)In: PACIFIC JOURNAL OF MATHEMATICS FOR INDUSTRY, ISSN 2198-4115, Vol. 10, article id 5Article in journal (Refereed) Published
##### Abstract [en]

A 3-D continuum mixture model describing the corrosion of concrete with sulfuric acid is built. Essentially, the chemical reaction transforms slaked lime (calcium hydroxide) and sulfuric acid into gypsum releasing water. The model incorporates the evolution of chemical reaction, diffusion of species within the porous material and mechanical deformations. This model is applied to a 1-D problem of a plate-layer between concrete and sewer air. The influx of slaked lime from the concrete and sulfuric acid from the sewer air sustains a gypsum creating chemical reaction (sulfatation or sulfate attack). The combination of the influx of matter and the chemical reaction causes a net growth in the thickness of the gypsum layer on top of the concrete base. The model allows for the determination of the plate layer thickness h = h(t) as function of time, which indicates both the amount of gypsum being created due to concrete corrosion and the amount of slaked lime and sulfuric acid in the material. The existence of a parameter regime for which the model yields a non-decreasing plate layer thickness h(t) is identified numerically. The robustness of the model with respect to changes in the model parameters is also investigated.

##### Place, publisher, year, edition, pages
London, UK: Springer, 2018
##### Keywords
Reaction-diffusion, Mechanics, Mixture theory, Concrete corrosion, Sulfatation attack
##### National Category
Computer Sciences
Computer Science
##### Identifiers
urn:nbn:se:kau:diva-69344 (URN)10.1186/s40736-018-0039-6 (DOI)000443948600003 ()
Available from: 2018-09-20 Created: 2018-09-20 Last updated: 2018-10-18Bibliographically approved
Lind, M. & Muntean, A. (2018). A Priori Feedback Estimates for Multiscale Reaction-Diffusion Systems. Numerical Functional Analysis and Optimization, 39(4), 413-437
Open this publication in new window or tab >>A Priori Feedback Estimates for Multiscale Reaction-Diffusion Systems
2018 (English)In: Numerical Functional Analysis and Optimization, ISSN 0163-0563, E-ISSN 1532-2467, Vol. 39, no 4, p. 413-437Article in journal (Refereed) Published
##### Abstract [en]

We study the approximation of a multiscale reaction–diusion system posed on both macroscopic and microscopic space scales. The coupling between the scales is done through micro– macro ux conditions. Our target system has a typical structure for reaction–diusion ow problems in media with distributed microstructures (also called, double porosity materials). Besides ensuring basic estimates for the convergence of two-scale semidiscrete Galerkin approximations, we provide a set of a priori feedback estimates and a local feedback error estimator that help in designing a distributed-high-errors strategy to allow for a computationally ecient zooming in and out from microscopic structures. The error control on the feedback estimates relies on two-scale-energy, regularity, and interpolation estimates as well as on a ne bookeeping of the sources responsible with the propagation of the (multiscale) approximation errors. The working technique based on a priori feedback estimates is in principle applicable to a large class of systems of PDEs with dual structure admitting strong solutions. A

##### Place, publisher, year, edition, pages
Taylor & Francis, 2018
##### Keywords
Feedback nite element method, Galerkin approximation, micro–macro coupling, multiscale reaction–diusion systems
Mathematics
Mathematics
##### Identifiers
urn:nbn:se:kau:diva-62808 (URN)10.1080/01630563.2017.1369996 (DOI)
Available from: 2017-08-25 Created: 2017-08-25 Last updated: 2018-05-22Bibliographically approved
Matsui, K. & Muntean, A. (2018). Asymptotic analysis of an ε-Stokes problem connecting Stokes and pressure-Poisson problems. Advances in Mathematical Sciences and Applications, 27(1), 181-191
Open this publication in new window or tab >>Asymptotic analysis of an ε-Stokes problem connecting Stokes and pressure-Poisson problems
2018 (English)In: Advances in Mathematical Sciences and Applications, ISSN 1343-4373, Vol. 27, no 1, p. 181-191Article in journal (Refereed) Published
##### Abstract [en]

In this Note, we prepare an ε-Stokes problem connecting the Stokes problem and the corresponding pressure-Poisson equation using one parameter ε > 0. We prove that the solution to the ε-Stokes problem, convergences as ε tends to 0 or ∞ to the Stokes and pressure-Poisson problem, respectively.

##### Place, publisher, year, edition, pages
Tokyo, Japan: Gakkotosho, 2018
##### Keywords
Stokes problem, Pressure-Poisson equation, Asymptotic analysis
##### National Category
Mathematical Analysis
Mathematics
##### Identifiers
urn:nbn:se:kau:diva-67313 (URN)
Available from: 2018-05-11 Created: 2018-05-11 Last updated: 2019-03-12Bibliographically approved
Muntean, A. & Seidman, T. I. (2018). Asymptotics of diffusion-limited fast reactions. Quarterly of Applied Mathematics, 76, 199-213
Open this publication in new window or tab >>Asymptotics of diffusion-limited fast reactions
2018 (English)In: Quarterly of Applied Mathematics, ISSN 0033-569X, E-ISSN 1552-4485, Vol. 76, p. 199-213Article in journal (Refereed) Published
##### Place, publisher, year, edition, pages
American Mathematical Society (AMS), 2018
##### Keywords
Fast reaction, diffusion, asymptotics
Mathematics
Mathematics
##### Identifiers
urn:nbn:se:kau:diva-47555 (URN)10.1090/qam/1496 (DOI)
Available from: 2016-12-25 Created: 2016-12-25 Last updated: 2018-05-23Bibliographically approved
Gruetzner, S. & Muntean, A. (2018). Brief Introduction to Damage Mechanics and its Relation to Deformations. In: van Meurs, Patrick, Kimura, Masato, Notsu, Hirofumi (Ed.), Mathematical Analysis of Continuum Mechanics and Industrial Applications II: Proceedings of the International Conference CoMFoS16 (pp. 115-124). Springer
Open this publication in new window or tab >>Brief Introduction to Damage Mechanics and its Relation to Deformations
2018 (English)In: Mathematical Analysis of Continuum Mechanics and Industrial Applications II: Proceedings of the International Conference CoMFoS16 / [ed] van Meurs, Patrick, Kimura, Masato, Notsu, Hirofumi, Springer, 2018, p. 115-124Chapter in book (Refereed)
##### Abstract [en]

We discuss some principle concepts of damage mechanics and outline a possibility to address the open question of the damage-to-deformation relation by suggesting a parameter identification setting. To this end, we introduce a variable motivated by the physical damage phenomenon and comment on its accessibility through measurements. We give an extensive survey on analytic results and present an isotropic irreversible partial damage model in a dynamic mechanical setting in form of a second order hyperbolic equation coupled with an ordinary differential equation for the damage evolution. We end with a note on a possible parameter identification setting.

Springer, 2018
##### Series
Mathematics for Industry, ISSN 2198-350X ; 30
##### Keywords
damage, mechanics of solids, non-linear differential equations, parameter identification
Mathematics
##### Research subject
Materials Engineering; Mathematics
##### Identifiers
urn:nbn:se:kau:diva-63936 (URN)978-981-10-6283-4 (ISBN)
Available from: 2017-09-24 Created: 2017-09-24 Last updated: 2018-06-28Bibliographically approved
Muntean, A. & Reichelt, S. (2018). Corrector estimates for a thermo-diffusion model with weak thermal coupling. Multiscale Modeling & simulation, 16(2), 807-832
Open this publication in new window or tab >>Corrector estimates for a thermo-diffusion model with weak thermal coupling
2018 (English)In: Multiscale Modeling & simulation, ISSN 1540-3459, E-ISSN 1540-3467, Vol. 16, no 2, p. 807-832Article in journal (Refereed) Published
##### Abstract [en]

The present work deals with the derivation of corrector estimates for the two-scale homogenization of a thermodiffusion model with weak thermal coupling posed in a heterogeneous medium endowed with periodically arranged high-contrast microstructures. The term “weak thermal coupling” refers here to the variable scaling in terms of the small homogenization parameter $\varepsilon$ of the heat conduction-diffusion interaction terms, while the “high-contrast” is considered particularly in terms of the heat conduction properties of the composite material. As a main target, we justify the first-order terms of the multiscale asymptotic expansions in the presence of coupled fluxes, induced by the joint contribution of Sorret and Dufour-like effects. The contrasting heat conduction combined with cross coupling leads to the main mathematical difficulty in the system. Our approach relies on the method of periodic unfolding combined with $\varepsilon$-independent estimates for the thermal and concentration fields and for their coupled fluxes.

##### Place, publisher, year, edition, pages
Society for Industrial and Applied Mathematics, 2018
Mathematics
Mathematics
##### Identifiers
urn:nbn:se:kau:diva-65815 (URN)10.1137/16M109538X (DOI)000436998500009 ()
Available from: 2018-01-25 Created: 2018-01-25 Last updated: 2018-09-05Bibliographically approved
Richardson, O., Jalba, A. & Muntean, A. (2018). Effects of Environment Knowledge in Evacuation Scenarios Involving Fire and Smoke: A Multiscale Modelling and Simulation Approach. Fire technology, 55(2), 415-436
Open this publication in new window or tab >>Effects of Environment Knowledge in Evacuation Scenarios Involving Fire and Smoke: A Multiscale Modelling and Simulation Approach
2018 (English)In: Fire technology, ISSN 0015-2684, E-ISSN 1572-8099, Vol. 55, no 2, p. 415-436Article in journal (Refereed) Published
##### Abstract [en]

We study the evacuation dynamics of a crowd evacuating from a complex geometry in the presence of a fire as well as of a slowly spreading smoke curtain.The crowd is composed of two kinds of individuals: those who know the layout of the building, and those who do not and rely exclusively on potentially informed neighbors to identify a path towards the exit. We aim to capture the effect the knowledge of the environment has on the interaction between evacuees and their residence time in the presence of fire and evolving smoke. Our approach is genuinely multiscale—we employ a two-scale model that is able to distinguish between compressible and incompressible pedestrian flow regimes and allows for micro and macro pedestrian dynamics. Simulations illustrate the expected qualitative behavior of the model. We finish with observations on how mixing evacuees with different levels of knowledge impacts important evacuation aspects.

Springer, 2018
##### Keywords
Crowd dynamics, Environment knowledge, Evacuation, Fire and smoke dynamics, Particle methods, Transport processes, Incompressible flow, Smoke, Transport process, Fires
Mathematics
Mathematics
##### Identifiers
urn:nbn:se:kau:diva-68390 (URN)10.1007/s10694-018-0743-x (DOI)000460581600003 ()2-s2.0-85048553425 (Scopus ID)
Available from: 2018-07-04 Created: 2018-07-04 Last updated: 2019-04-05Bibliographically approved
Colangeli, M., Muntean, A., Richardson, O. & Thieu, T. K. (2018). Modelling interactions between active and passive agents moving through heterogeneous environments. In: Livio Gibelli, Nicola Bellomo (Ed.), Crowd Dynamics: volume 1 (pp. 211-257). Basel: Springer
Open this publication in new window or tab >>Modelling interactions between active and passive agents moving through heterogeneous environments
2018 (English)In: Crowd Dynamics: volume 1 / [ed] Livio Gibelli, Nicola Bellomo, Basel: Springer , 2018, p. 211-257Chapter in book (Refereed)
##### Abstract [en]

We study the dynamics of interacting agents from two distinct intermixed populations: one population includes active agents that follow a predetermined velocity field, while the second population contains exclusively passive agents, i.e., agents that have no preferred direction of motion. The orientation of their local velocity is affected by repulsive interactions with the neighboring agents and environment. We present two models that allow for a qualitative analysis of these mixed systems. We show that the residence times of this type of systems containing mixed populations is strongly affected by the interplay between these two populations. After showing our modelling and simulation results, we conclude with a couple of mathematical aspects concerning the well-posedness of our models.

##### Place, publisher, year, edition, pages
Basel: Springer, 2018
##### Keywords
Crowd dynamics, Fire and smoke dynamics, Heterogeneous domains, Lattice gas model, Particle methods
Mathematics
##### Identifiers
urn:nbn:se:kau:diva-71296 (URN)10.1007/978-3-030-05129-7_8 (DOI)2-s2.0-85061059980 (Scopus ID)978-3-030-05128-0 (ISBN)
Available from: 2019-02-21 Created: 2019-02-21 Last updated: 2019-03-22Bibliographically approved
##### Identifiers
ORCID iD: orcid.org/0000-0002-1160-0007

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