Sebastian Meier

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Transport and reaction of carbon dioxide with alkaline species in concrete is modelled by a closed system of ordinary and partial differential equations. Varying porosity and varying external exposure as well as nonlinear reaction rates are taken into account. Proper nondi-mensionalisation is introduced to pay attention to the different characteristic time(More)
Fachbereich 3 – Mathematik und Informatik A note on limitations of the use of accelerated concrete-carbonation tests for service-life predictions Abstract Concrete carbonation is a process that can limit the lifetime of reinforced concrete structures. The resistance of concrete samples to carbonation is usually determined by accelerated tests under(More)
We discuss the fast-reaction limit of a two-scale reaction-diffusion model. We point out that if the reaction constant a explodes to infinity, then a two-scale PDEs system with free boundary at the micro cell is obtained. The aim of this note is to answer the question: Can the same two-scale free-boundary problem be obtained if we first pass to the(More)
Concrete carbonation, i.e. the reaction of alkaline species (inside the concrete) with atmospheric carbon dioxide, is one of the major physicochemical processes compromising the service life of concrete structures. While the main carbonation reaction is that of calcium hy-droxide, other constituents such as calcium silicates or calcium-silcate hydrates in(More)
We investigate a reaction–diffusion process in a two-phase medium with microscopic length scale ε. The diffusion coefficients in the two phases are highly different (d 1 /D = ε 2) and the reaction constant k is large. First, the homogenisation limit ε → 0 is taken, which leads to a two-scale model. Afterwards, we pass to the fast-reaction limit k → ∞ and(More)
Oxide-derived copper (OD-Cu) electrodes exhibit unprecedented CO reduction performance towards liquid fuels, producing ethanol and acetate with >50% Faradaic efficiency at -0.3 V (vs. RHE). By using static headspace-gas chromatography for liquid phase analysis, we identify acetaldehyde as a minor product and key intermediate in the electroreduction of CO to(More)
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