Confinement controls the creep rate in soft granular packings.

Flow in soft materials encompasses a wide range of viscous, plastic and elastic phenomena which provide challenges to modelling at the microscopic level. To create a controlled flow, we perform falling ball viscometry tests on packings of soft, frictionless hydrogel spheres. Systematic creep flow is found when a controlled driving stress is applied to a sinking sphere embedded in a packing.

Creep Control in Soft Particle Packings.

Granular packings display a wealth of mechanical features that are of widespread significance. One of these features is creep: the slow deformation under applied stress. Creep is common for many other amorphous materials such as many metals and polymers.

On the buckling of elastic rings by external confinement.

We report the results of an experimental and numerical investigation into the buckling of thin elastic rings confined within containers of circular or regular polygonal cross section. The rings float on the surface of water held in the container and controlled removal of the fluid increases the confinement of the ring. The increased compressive forces can cause the ring to buckle into a variety of shapes.

Granular segregation in a thin drum rotating with periodic modulation.

We present the results of an experimental investigation into the effects of a sinusoidal modulation of the rotation rate on the segregation patterns formed in thin drum of granular material. The modulation transforms the base pattern formed under steady conditions by splitting or merging the initial streaks. Specifically, the relation between the frequency of modulation and the rotation rate determines the number of streaks which develop from the base state.

Effects of foot-pedal positions by inexperienced cyclists at the highest aerobic level.

The purpose of this study was to assess whether the platform foot-pedal position affected maximal oxygen intake (VO2 max) at the highest aerobic demand in cycling. 21 inexperienced cyclists completed two exercise tests, one in the "normal" platform foot-pedal position and the other in the Biopedal forefoot varus foot-pedal position, cycling on an exercise ergometer. The time between tests ranged from 1 to 3 days depending on the subject's reported fatigue and muscle soreness.

Granular segregation as a critical phenomenon.

We present the results of an experimental study of patterned segregation in a horizontally shaken shallow layer of a binary mixture of dry particles. An order parameter for the segregated domains is defined and the effect of the variation of the combined filling fraction, C, of the mixture on the observed pattern formation is systematically studied. We find that there is a critical event associated with the onset of segregation, at C(c)=0.