The Rκκ function and its applications: disentropy, image processing and the κ-diode J. L. E. da Silva, F. V. Mendes and R. V. Ramos Eur. Phys. J. Plus, 137 3 (2022) 320 Published online: 09 March 2022 DOI: 10.1140/epjp/s13360-022-02555-4