  In a half-filled rotating drum, the size segregation of particles of equal
density builds a ring pattern of the large particles, whose location
continuously varies from the periphery to the center depending on the size
ratio between particles [Thomas, Phys. Rev. E 62, 1 (2000) 961-974]. For small
size ratios (typically15): large beads are close to the bottom in a reversing
position. The existence of circles with an intermediate radius shows that the
segregation at an intermediate level within a flow is possible. In this paper,
we experimentally study the segregation of particles of different densities and
sizes in a half-filled rotating drum and other devices (chute flow, pile). In
the drum, the location of the segregated ring continuously varies from the
periphery to the center and is very sensitive to both the size (from 1 to 33)
and density (from 0.36 to 4.8) ratios. The densest large beads segregate on a
circle close to the center, the lightest large beads on a circle close to the
periphery. Consequently, we found that for any tracer, its excess of mass, due
to only a size excess, a density excess, or both, leads to a deep inside
segregation of the tracer. There is a push-away process that makes heavy beads
of any type go downwards, while the excess of size is already known to push
large beads towards the surface, by a dynamical sieving process. Each
segregation at an intermediate ring corresponds to a balance between these mass
and geometrical effects. The segregation level in the flow is determined by the
ratio of the intensities of both effects.
