Bo Persson, Jülich Research Center (IMAGE) American Institute of Physics Caption For more than 20 years, Bo Persson, a scientist at the Jülich Research Center, has studied friction. Persson developed a set of equations describing the complex phenomenon of rubber friction, which he and his colleagues recently tested for blocks of rubber sliding across rough road surfaces. Credit FZ Jülich Usage Restrictions This image may only be used with proper caption and credit. 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.