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- Aiki, Toyohiko, et al.
(author)
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Large-time asymptotics of moving-reaction interfaces involving nonlinear Henry’s law and time-dependent Dirichlet data
- 2013
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In: Nonlinear Analysis. - : Elsevier. - 0362-546X .- 1873-5215. ; 93, s. 3-14
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Journal article (peer-reviewed)abstract
- We study the large-time behavior of the free boundary position capturing the one-dimensional motion of the carbonation reaction front in concrete-based materials. We extend here our rigorous justification of the t-behavior of reaction penetration depths by including nonlinear effects due to deviations from the classical Henry's law and time-dependent Dirichlet data.
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| 5. |
- Aiki, Toyohiko, et al.
(author)
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On uniqueness of a weak solution of one-dimensional concrete carbonation problem
- 2011
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In: Discrete and Continuous Dynamical Systems. - : American Institute of Mathematical Sciences. - 1078-0947 .- 1553-5231. ; 29:4, s. 1345-1365
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Journal article (peer-reviewed)abstract
- In our previous works we studied a one-dimensional free-boundary model related to the aggressive penetration of gaseous carbon dioxide in unsaturated concrete. Essentially, global existence and uniqueness of weak solutions to the model were obtained when the initial functions are bounded on the domain. In this paper we investigate the well-posedness of the problem for the case when the initial functions belong to a class. Specifically, the uniqueness of weak solutions is proved by applying the dual equation method.
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| 6. |
- Aiki, T., et al.
(author)
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Preface
- 2012
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In: Discrete and Continuous Dynamical Systems. Series S. - : American Institute of Mathematical Sciences (AIMS). - 1937-1632 .- 1937-1179. ; 5:1, s. 1-
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Journal article (peer-reviewed)
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| 7. |
- Chalupecky, Vladimir, et al.
(author)
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Macroscopic corrosion front computations of sulfate attack in sewer pipes based on a micro-macro reaction-diffusion model
- 2012
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In: Multiscale Mathematics. - : Kyushu University, Japan. ; , s. 22-31
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Conference paper (peer-reviewed)abstract
- We consider a two-scale reaction diffusion system able to capture the corrosion of concrete with sulfates. Our aim here is to define and compute two macroscopic corrosion indicators: typical pH drop and gypsum profiles. Mathematically, the system is coupled, endowed with micro-macro transmission conditions, and posed on two different spatially-separated scales: one microscopic (pore scale) and one macroscopic (sewer pipe scale). We use a logarithmic expression to compute values of pH from the volume averaged concentration of sulfuric acid which is obtained by resolving numerically the two-scale system (microscopic equations with direct feedback with the macroscopic diffusion of one of the reactants). Furthermore, we also evaluate the content of the main sulfatation reaction (corrosion) product---the gypsum---and point out numerically a persistent kink in gypsum's concentration profile. Finally, we illustrate numerically the position of the free boundary separating corroded from not-yet-corroded regions.
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| 9. |
- Cirillo, Emilio N. M., et al.
(author)
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Can cooperation slow down emergency evacuations?
- 2012
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In: Comptes rendus. Mecanique. - : Elsevier. - 1631-0721 .- 1873-7234. ; 340:9, s. 625-628
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Journal article (peer-reviewed)abstract
- We study the motion of pedestrians through obscure corridors where the lack of visibility hides the precise position of the exits. Using a lattice model, we explore the effects of cooperation on the overall exit flux (evacuation rate). More precisely, we study the effect of the buddying threshold (of no–exclusion per site) on the dynamics of the crowd. In some cases, we note that if the evacuees tend to cooperate and act altruistically, then their collective action tends to favor the occurrence of disasters.
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| 10. |
- Cirillo, Emilio N.M., et al.
(author)
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Dynamics of pedestrians in regions with no visibility : A lattice model without exclusion
- 2013
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In: Physica A: Statistical Mechanics and its Applications. - : Elsevier. - 0378-4371. ; 392:17, s. 3578-3588
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Journal article (peer-reviewed)abstract
- We investigate the motion of pedestrians through obscure corridors where the lack of visibility (due to smoke, fog, darkness, etc.) hides the precise position of the exits. We focus our attention on a set of basic mechanisms, which we assume to be governing the dynamics at the individual level. Using a lattice model, we explore the effects of non-exclusion on the overall exit flux (evacuation rate). More precisely, we study the effect of the buddying threshold (of no-exclusion per site) on the dynamics of the crowd and investigate to which extent our model confirms the following pattern revealed by investigations on real emergencies: If the evacuees tend to cooperate and act altruistically, then their collective action tends to favor the occurrence of disasters. The research reported here opens many fundamental questions and should be seen therefore as a preliminary investigation of the very complex behavior of the people and their motion in dark regions.
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