Permeability in Thin, Glass Sphere Walls (IMAGE) The American Ceramics Society Caption Schematic representation of microsphere wall porosity. Credit Savannah River National Lab, American Ceramics Society Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.