Bread and Pumice

Pumice-pumice collisions and the effect of the impact angle

[1] Using a high-speed video camera, we studied oblique collisions of lapilli-size pumice cylinders (with no rotation before impact) on flat pumice targets. Our results show that the rebound angle, the ratios of the components of velocities and the energy loss vary with the impact angle. In particular, in collisions with an average yaw angle approximately equal to zero, we observed relatively l...

Bread and Circuses

In the past, too little thought has been given to the relationship of culture to play. That the forms of play have varied with different cultural epochs is often forgotten; even more rarely mentioned is the idea that culture arises in the form of play, and play needs to be born. This is the main thesis of Professor Huizinga's important and absorbing book, Homo Ludens.1 He argues that culture is...

Pumice Aggregates for Internal Water Curing

A novel concept in internal curing of High Performance Concrete is based on dispersing very small, saturated lightweight aggregates (LWA) in the concrete, containing sufficient water to counteract self-desiccation. With this approach, the amount of water in the LWA can be minimized, thus economizing on the amount of the LWA. In this study, the pore structure of different size fractions of pumic...

Recovering DNA from agarose gels with pumice.

Rapid, Long-Distance Dispersal by Pumice Rafting

Pumice is an extremely effective rafting agent that can dramatically increase the dispersal range of a variety of marine organisms and connect isolated shallow marine and coastal ecosystems. Here we report on a significant recent pumice rafting and long-distance dispersal event that occurred across the southwest Pacific following the 2006 explosive eruption of Home Reef Volcano in Tonga. We hav...