I am an Acoustical Engineer student from the Universidad Austral de Chile, Valdivia. I am working on my Enginery thesis at the Physics Department of the Faculty of Physical and Mathematical Sciences of the University of Chile, my advisor is Nicolás Mujica. We are using two ultrasound techniques, pulse propagation and Resonant Ultrasound Spectroscopy, in order to characterize materials. In particular we are interested in the possibility if measuring non-invasively dislocation density in metals.