Sheaths drive powerful new artificial muscles. Over the last 15 years, researchers at The University of Texas at Dallas and their international colleagues have invented several types of strong, powerful artificial muscles using materials ranging from high-tech carbon nanotubes (CNTs) to ordinary fishing line. In a new study published July 12, 2019 in the journal Science, the researchers describe their latest advance, called sheath-run artificial muscles, or SRAMs. Source 5x.