Sheath-Run Artificial Muscle (IMAGE) University of Texas at Dallas Caption This illustration shows a twisted carbon nanotube yarn (CNT) (left) and a sheath-run artificial muscle (SRAM) made by coating a twisted CNT yarn with a polymer sheath. A scanning electron microscope image of a 42-micron outer-diameter coiled SRAM is shown on the right. Credit The University of Texas at Dallas Usage Restrictions with 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.