title: Magnetic field induced inversion in the effect of particle size on powder cohesiveness.
abstract: Experimental measurements are reported on the tensile yield stress of magnetofluidized beds of fine magnetic powders operated in the cross-flow configuration. In the absence of externally applied magnetic field the yield stress of the powder depends on particle size as expected, i.e., it increases as bead size is decreased. This trend is however inverted when an external magnetic field is applied. It is suggested that the average orientation of interparticle contacts relative to the direction of the field as affected by particle size plays a relevant role on the magnetic yield stress of these systems.
authors.affiliation: Department of Applied Physics II, University of Seville, Avenida Reina Mercedes s/n, 41012 Sevilla, Spain.
authors.forename: M J
authors.initials: MJ
authors.lastname: Espin
authors.forename: J M
authors.initials: JM
authors.lastname: Valverde
authors.forename: M A S
authors.initials: MA
authors.lastname: Quintanilla
authors.forename: A
authors.initials: A
authors.lastname: Castellanos