AA << report remarkably persistent mixing and non-mixing regions in a three-dimensional dynamical system where randomness is expected. A spherical shell half-filled with dry non-cohesive particles and periodically rotated about two horizontal axes generates complex structures that vary non-trivially with the rotation angles. >>
Zafir Zaman, Mengqi Yu, et al. Persistent structures in a three-dimensional dynamical system with flowing and non-flowing regions. Nature Comm vol 9, no 3122 (2018) doi: 10.1038/s41467-018-05508-7
https://www.nature.com/articles/s41467-018-05508-7
Emily Ayshford. When mixing granular matter, order among disorder. Northwestern University. Aug 14, 2018.