title: Magnetic resonance imaging of chemical waves in porous media.
abstract: Magnetic resonance imaging (MRI) provides a powerful tool for the investigation of chemical structures in optically opaque porous media, in which chemical concentration gradients can be visualized, and diffusion and flow properties are simultaneously determined. In this paper we give an overview of the MRI technique and review theory and experiments on the formation of chemical waves in a tubular packed bed reactor upon the addition of a nonlinear chemical reaction. MR images are presented of reaction-diffusion waves propagating in the three-dimensional (3D) network of channels in the reactor, and the 3D structure of stationary concentration patterns formed via the flow-distributed oscillation mechanism is demonstrated to reflect the local hydrodynamics in the packed bed. Possible future directions regarding the influence of heterogeneities on transport and reaction are discussed.
authors.affiliation: Department of Chemistry, University of Leeds, Leeds, LS2 9JT, United Kingdom. A.F.Taylor@leeds.ac.uk
authors.forename: Annette F
authors.initials: AF
authors.lastname: Taylor
authors.forename: Melanie M
authors.initials: MM
authors.lastname: Britton
mesh_terms: D004058:Diffusion; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007477:Ions; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008345:Manganese / Q000737:chemistry; D008956:Models, Chemical; D015233:Models, Statistical; D008962:Models, Theoretical; D017711:Nonlinear Dynamics; D009991:Oscillometry; D016062:Porosity; D012815:Signal Processing, Computer-Assisted
chemical_list: D007477:Ions; D008345:Manganese