Comment on: Measurement of the force exerted on the surface of an object immersed in a plasma - Eur. Phys. J. D 69: 91 (2015), DOI: 10.1140/epjd/e2015-50743-2Uwe Czarnetzki and Tsanko V. TsankovEur. Phys. J. D, 69 10 (2015) 236DOI: https://doi.org/10.1140/epjd/e2015-60399-5