Supercomputing Institute Research Bulletin Newsletter of the University of Minnesota Supercomputing Institute Volume 14 Number 1 Fall 1997

In This Issue: 1997 Research Scholars LCPC Workshop T3E Upgrade Computing Applications in Neuroscience Unraveling Protein Structures Silicon Nanocrystals Research Reports   Institute Welcomes 1997 Research Scholars The Supercomputing Institute is pleased to announce the appointment of eight research scholars for 1997–98. Research scholars are postdoctoral associates who work closely with Supercomputing Institute principal investigators. Their work is supported by the Institute and by federal grants. Arkady Ten, who earned his Ph.D. from the Institute of Thermophysics in Novosibirsk, Russia, is working with Professor David Yuen in the Department of Geology and Geophysics. Ten is researching convection in the earth’s mantle with a particular focus on mixing in thermoconvection. He is monitoring material advection in a thermally unstable system and is also using fractal analysis to obtain a quantitative estimation of mantle mixing. This estimation could bridge the relatively abstract computer simulations of mantle convection and the purely physical work of geologists and geochemists. George Karypis, who earned his Ph.D. at the University of Minnesota, begins his second year as a research scholar working with Professor Vipin Kumar in the Department of Computer Science and Engineering. Karypis’s research interests span the areas of parallel algorithm design, applications of parallel processing in scientific computing and optimization, sparse matrix computations, parallel programming languages and libraries, and data mining. His recent work is in the areas of parallel sparse direct solvers, serial and parallel graph partitioning algorithms, parallel matrix ordering algorithms, and scalable parallel preconditioners. His research has resulted in the development of software libraries for unstructured mesh partitioning (Metis and Parmetis) and for parallel Cholesky factorization. Cesar Renato Simenes da Silva, who earned his Ph.D. at the Federal University of Rio Grande do Sul, Brazil, is working with Professor Renata Wentzcovitch in the Department of Chemical Engineering and Materials Science. He is currently working to port a first principles molecular dynamics code to the Cray T3E parallel computer. The program is a core tool for investigating high pressure phase formation. It uses a plane wave basis set. The main difficulty with such a program is writing a suitable parallel fast Founier transform. Serdar Ögüt, who earned his Ph.D. from Yale University, begins his third year at the University of Minnesota, where he has collaborated with Professor James Chelikowsky in the Department of Chemical Engineering and Materials Science. His latest work on the quantum confinement effects in silicon nanocrystals is detailed on page 11. He has been performing real-space ab initio pseudopotential calculations to investigate the structural and electronic properties of various physical systems, including clusters, bulk vacancies, and semiconductor nanocrystals. Joseph Olejniczak, who earned his Ph.D. from the University of Minnesota, is working with Professor Graham Candler in the Department of Aerospace Engineering and Mechanics. Their work was detailed in the summer issue of the Research Bulletin. Olejniczak researches computational fluid dynamics of hypersonic flows in thermo-chemical nonequilibrium. In particular, he is interested in designing experiments to obtain data that can be used to validate the numerical methods and physical models used in the computations. Maria Topaler, who earned her Ph.D. from Moscow State University, begins her second year working with Professor Donald Truhlar in the Department of Chemistry. Topaler uses quantum mechanical and semiclassical methods to study photochemical reactions. These reactions include photodissociation of electronically excited van der Waals molecules and nonadiabatic collisions of metal atoms with diatomic molecules. Topaler is testing existing approximate, semiclassical methods against more accurate quantum mechanical results and trying to develop new semiclassical methods for practical yet accurate dynamics calculations on a variety of photochemical reactions. One interesting question still to be resolved is the femtosecond dynamics of metastable funnel states. Ching-i Huang, who earned her Ph.D. from Northwestern University, is working with Professor Tim Lodge in the Department of Chemistry. She is researching the phase behavior of block copolymer systems, which are of great interest because of their ability to self-assemble into various ordered structures. These morphologies have novel material properties and valuable technical applications. Huang is mapping the phase diagram of copolymer solutions using self-consistent field theory. Her emphasis is on the regions of complex phase behavior where experimental systems display a sequence of bicontinuous cubic phases that may or may not be in equilibrium. Rogene Eichler West, who received her Ph.D. from the University of Minnesota, is a visiting research scholar working with Professor of Pharmacology George Wilcox. She holds a joint post-doctoral appointment at the California Institute of Technology and the University of Antwerp, Belgium. She uses computer models to study the importance of variability in the form and function of the nervous system. At the Supercomputing Institute, she has developed parameter exploration methods which run as parallel applications in heterogeneous computing environments. Her research is discussed further in Computing Applications in Neuroscience.