20140605 Talk at ASA Spring Meeting: Shear wave propagation in worm-like micellar fluids

Josh R. Gladden, Rachel Crim, Amanda Gamble and Cecille Labuda. Shear wave propagation in worm-like micellar fluids. J. Acoust. Soc. Am. 135, 2218 (2014).

Abstract. In viscous Newtonian fluids, support of shear waves are limited to the viscous boundary layer. Non-Newtonian fluids which have shear modulus, however, support shear waves over much longer distances. The restoring force responsible for the shear wave propagation arises from the entanglement of high aspect ratio macromolecules. We report low frequency (30–60 Hz) shear wave studies of aqueous worm-like micellar fluids composed of cetyltrimethylammonium bromide (CTAB) for the surfactant and sodium salicylate (NaSAL) as the salt over a wide concentration range (20–500 mM CTAB). Shear speeds range from 75 to 700 mm/s over this concentration range at room temperature with evidence of two phase transitions at 200 mM and 375 mM CTAB. Shear stress attenuation and temperature resolved measurements between 20 and 40 C will also be presented.

20140411 SPS LIGO Lab Tour

The UM SPS took a day trip to Livingston LA for a tour of the LIGO lab. The lab tour was organized by Dr. Cavaglia, a UM Physics faculty member, who is the leader of the LIGO team at UM and Assistant Spokeperson of the LIGO Scientific Collaboration. He accompanied ten SPS students along with Dr. Labuda the SPS faculty coordinator to the LIGO lab.

The group was treated to a tour of the control room, the scientific measurement facility itself and the Science Center.
Click here for a gallery of the SPS LIGO lab tour.