Visiting Assistant Professor
Department of Physics
Courses Taught at PC
Physics with Calculus I, II, and III
Methods of Theoretical Physics
Heat and Thermodynamics
My research interests center around granular physics. Granular matter makes up a large class of materials, from the everyday such as sand grains on the beach to the more exotic rings of Saturn. More formally, granular materials are a collection of large athermal particles that interact with each other through a strictly repulsive contact potential. There are many interesting phenomena associated with granular materials, for instance, the industrially important process of particle segregation and mixing or the pressure screening in grain silos. Another interesting feature is that the internal force structure of granular materials is very heterogeneous. These internal forces can be visualized using a 2D photoelastic granular material (see figure). As can be seen, the forces have a branching structure made up of the so called force chains.
Granular Physics Demonstrations
Granular materials, for example sand, provide several opportunities for physics demonstrations. Composed of macroscopic particles interacting in a purely classical way through the particle contacts, granular materials have many industrial applications and are one of the most commonly transported materials. Granular physics is also relevant in many geophysics and astrophysics studies, yet physics students are rarely introduced to this important class of materials. Granular materials also display some interesting phenomena. For example, two different types of particles tend to segregate in seeming violation of increasing entropy. At the 2012 AAPT meeting in Philadelphia, I presented a poster that showed and explained granular physics demonstrations illustrating these and many other interesting granular physics principles. These demonstrations are very eye catching and many can be constructed using simple household materials.
The poster presented at the AAPT 2012 is available below:
Eli T. Owens and Karen E. Daniels. Acoustic measurement of a granular density of modes Soft Matter 9:1214 (2013) [Link]
Danielle S. Bassett, Eli T. Owens, Karen E. Daniels, Mason A. Porter. Influence of Topology on Signal Propagation in Granular Force Networks. Physical Review E 86: 041306 (2012) [Link]
Eli T. Owens and Karen E. Daniels. Sound propagation and force chains in granular materials. Europhysics Letters 94, 54005 (2011) [Link]
Eli T. Owens, Stephanie Couvreur and Karen E. Daniels. Spatiotemporally Resolved Acoustics in a Photoelastic Granular Material. Powders and Grains 2009: Proceedings of the 6th International
Conference on Micromechanics of Granular Media, p. 447-450 (2009) [Link]
Martina E. Bachlechner, Deepak Srivastava, Eli T. Owens, Jarrod Schiffbauer, Jonas T. Anderson, Melissa R. Burky, Samuel C. Ducatman1,Adam M. Gripper, Eric J. Guffey, and Fernando Serrano Ramos. Mechanisms of pit formation at strained crystalline Si(111)/Si3N4(0001) interfaces: Molecular-dynamics simulations. Physical Review B 74, 075327 (2006) [Link]