Arching during the segregation of two-dimensional tapped granular systems: Mixtures versus intruders Rodolfo Omar Uñac, Jesica G. Benito, Ana María Vidales and Luis A. Pugnaloni Eur. Phys. J. E, 37 11 (2014) 117 Published online: 24 November 2014 DOI: 10.1140/epje/i2014-14117-y