Estimation of fuzzy band for radon transport mechanism in earth crust T. D. Rao, S. Chakraverty, P. Karunakar and B. K. Sahoo Eur. Phys. J. Plus, 138 3 (2023) 221 Published online: 09 March 2023 DOI: 10.1140/epjp/s13360-023-03778-9