Temperature (K)

1. Unusual behavior of glass has a crystalline originLiping Huang, Rensselaer Polytechnic Institute, DMR 0907076 Elastic Moduli (GPa) 100 Silica glass One of the unusual behaviors of silica glass is that it becomes stiffer upon heating (upper pane in the right-hand figure, Polian et al., 2002), which has confounded glass scientists for long time. Using molecular dynamics (MD) simulations, Liping Huang’s team at Rensselaer discovered that this unusual behavior has a crystalline origin. As seen in the lower pane of the right-hand figure, simulated cristobalite silica goes through an alpha-to-beta transformation upon heating and the bulk modulus continuously increases throughout the transformation regime due to the ring topology change from alpha to beta phase. Similar topology change is seen in silica glass upon heating, but much more gradual and local than in the crystalline counterpart. Guided by this finding, the Rensselaer team is synthesizing glasses with zero-temperature/pressure dependent elastic constants by tuning the glass structure through chemical modification and pressure-quenching. Such glasses will be more resistant to thermal and mechanical impacts. 90 C11 80 B Temperature (K) 40 C44 30 0 500 1000 1500 2000 2500 beta Cristobalite Silica alpha

2. Unusual behavior of glass has a crystalline originLiping Huang, Rensselaer Polytechnic Institute, DMR 0907076 Education: A primary educational activity for this grant is to re-design MTLE 6500: Modeling of Materials course. In this class, the PI covers commonly used theoretical and simulation methods at the electronic, atomistic, meso and continuum scales and complements lectures with hands-on computational modeling exercises using open source software packages. In Fall 2009, 21 students from six disciplines on campus (Materials, Physics, Geology, Mechanical Engineering, Nuclear Engineering, Biomedical Engineering) registered for the class. 6 students and postdoctoral researchers on campus audited, and one student from SUNY Albany and one student from SUNY Binghamton sit in the class. Graduate and Undergraduate Student Training:Two graduate students (Qing Zhao and Fenglin Yuan) and two undergraduate students (Russell Meredith and Garth Scannell) are working on this project as a team under the PI’s direct supervision. They are trained in the fields of glass science, light scattering and computer simulation. Outreach and Dissemination: The PI participated in the Primarily Undergraduate Institutions (PUI) Partnership Program at Rensselaer in the summer of 2009 and exposed freshmen through junior students from under-represented groups in engineering to the newest frontiers in glass science and technology. The PI is also familiarizing a wider audience with the crucial role played by glasses in cutting-edge applications through invited presentations at international conferences.