Iron Impurities in Carbon Nanotubes (IMAGE) Rice University Caption Iron impurities are easy to see in a bundle of carbon nanotubes viewed through a transmission electron microscope. Researchers at Rice University and the National University of Singapore are leading the charge to purify nanotubes for use in continuous, strong and conductive carbon nanotube fibers. Credit Complex Flows of Complex Fluids/Rice University Usage Restrictions For news reporting purposes only. 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.