the angle of repose of soil particles is an important factor for determining critical shear stress for initiation of soil particles motion during the erosion process. there are different methods for measuring the angle of particle repose and the result of each method is somewhat different from those of the others. sliding and fixed-base piling methods are the two most common methods in the lite...

According to USP 30-NF 25 [1], powder flow with repose angles between 25–30° powder flow is excellent, among 31–35° the flow is good and within 36–40° the flow is fair. For values higher than 41°, the powder has bad flow properties. The best angle of repose was shown by powder obtained from tests 4 and 6 (33 ± 2° and 33 ± 1° in Table S1), whose flow can be considered good. Moreover, the powders...

S U M M A R Y Volcanoes usually show signs of unrest before an eruption. Establishing physical controls on the duration of precursory activity, that is run-up time, could improve understanding of the dynamics of magma ascent from a shallowmagma reservoir to the surface. Another observable indicative of eruption dynamics is the interevent repose time, that is, the time betweenmagmatic eruptions....

Aiming at predicting what happens in reality inside mills, the contact parameters of iron ore particles for discrete element method (DEM) simulations should be determined accurately. To allow the irregular shape to be accurately determined, the sphere clump method was employed in modelling the particle shape. The inter-particle contact parameters were systematically altered whilst the contact p...

We investigate the effect of nanoscale variations in the surface roughness of individual particles on macroscale granular flow characteristics. Experiments were conducted in circular rotating tumblers with smooth and rough 2 and 3 mm steel particles. The smooth beads had a rms surface roughness of approximately 30 to 60 nm; rough beads had a surface roughness of approximately 240 to 350 nm. The...