. 2019 Apr 10;21(4):388. doi: 10.3390/e21040388
© 2019 by the authors.
Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
| η | efficiency (/) |
| ρ | density (kg/m3) |