Growth dynamics with heterogeneous

Intermediate periodic operation lies between both extremes and covers systems in which the response time is of the same order as the imposed function cycle time so that resonance is possible. Here the state of the mechanism changes dynamically and is not directly related to the environmental conditions at the moment considered. Intermediate periodic operations encompass semibatch periodic operations, selectivity in periodically forced CSTRs, cycled reactors with heterogeneous catalysts, and non-steady-state biofilm reactors (e.g., Rittmann and McCarty, 1981). Lag, overshoot phenomena, and oscillations can typically occur. Biological reactor operation will basically fall into this latter class of operation, and balanced growth must be distinguished from steady-state growth (Barford et al., 1982). 

Modeling of the gas phase chemistry and particle growth shows that homogeneous nucleation occurs early on in the process followed by heterogeneous condensation processes. Molecular dynamics computation have indicated that the iron oxide clusters will phase segregate and migrate toward the inside edge of the silica cluster consistent with experimental observation. 

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