In a study using a meso-scale reactor with embedded static mixer elements, particles with the mean size of ∼ 40-45 nm were obtained, similar to some of micro-reactor studies, but with a very broad size distribution . There is no data in the paper to calculate residence time or micromixing time for their specific system. It is therefore most likely that the choice of conditions for synthesis in the static-mixer fitted reactor was much larger than the micromixing time.