Fig. 3

Principle of the Knudsen levitation. The pores of the aggregate act as a collection of micro-channels. Thermal creep is induced by the temperature difference over the aggregate. The pressure increases below the aggregate, and the aggregate is then levitated. The levitation height is limited by the gas flow to the sides, which reduces the overpressure once the aggregate has been levitated (Kelling & Wurm 2009).
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.