Grad students Feifei Xu, Qinguang Quan, and Ryan Learn interned this summer at research laboratories, both abroad and at home in the U.S. Each student spent eight to ten weeks working with a professor/mentor on one or more research projects. The internships provided an ideal opportunity for the students to match analytical skills and computer aptitude to a select research environment.
Ryan Learn spent the summer at Lawrence Livermore National Laboratory in Livermore, California. Learn won an award for Best in Show for his research and presentation, “Mitigation of Numerical Aliasing for NIF Laser Simulations.” Learn added an absorbing boundary condition and an adaptive step-size algorithm to calculate the exact distance the NIF Laser can propagate. These additions have never been done before, and increased the accuracy of the calculation by approximately 20%. Learn also did some preliminary work to remove high frequency oscillations on laser pinholes. This work helps maintain the structure of the beam. Learn was mentored by Eyal Feigenbaum.
Feifei Xu summered in Beijing and worked with mathematician Qiang Du at the Computational Science Research Center. Xu’s research was on multiscale implementation of a nonlocal problems with focus on solutions for discontinuities. The goal of the project was to use a nonlocal equation near the region of discontinuity and a posterior estimator to adaptively capture where the discontinuity occurs. Once the discontinuity’s location is approximated, the mesh is refined, and the discontinuity and nearby regions are covered by long thin elements; uniform grid meshes are maintained for regions far away from the discontinuity. Xu and Du made progress this summer, and continue to work on the research. Xu was in Beijing from May to August.
For ten weeks, Qingguang Guan worked at Oak Ridge National Lab with Clayton Webster. Guan and Webster used reduced order basis methods to solve a class of nonlocal diffusion problems with random coefficients. These methods can model fractional diffusion phenomena with unknown coefficients.