RESUMO
We describe an experiment container with light scattering and imaging diagnostics for experiments on soft matter aboard the International Space Station (ISS). The suite of measurement capabilities can be used to study different materials in exchangeable sample cell units. The currently available sample cell units and future possibilities for foams, granular media, and emulsions are presented in addition to an overview of the design and the diagnostics of the experiment container. First results from measurements performed on ground and during the commissioning aboard the ISS highlight the capabilities of the experiment container to study the different materials.
RESUMO
We study the bubble rearrangement dynamics in aqueous foam during the passage from liquidlike to solidlike behavior which follows a transient shear deformation that perturbs the bubble packing. The local dynamics is probed using multispeckle diffusing-wave spectroscopy. We show that following the perturbation the average time between rearrangements relaxes exponentially, with time elapsed since the end of the perturbation. The observed scaling of the characteristic relaxation time with perturbation amplitude and foam age is explained by a schematic coarse-grained model based on the scaling state hypothesis.
