Friday, April 29, 2011
Graduate Students Receive Astrid and Bruce McWilliams Fellowships
Graduate students Colin DeGraf and Wenwen Li have been awarded Astrid and Bruce McWilliams Fellowships in the Mellon College of Science in recognition of their outstanding creativity, dedication and commitment to carrying out leading-edge research.
Colin DeGraf, a fourth year Ph.D. student in the Department of Physics, is analyzing large-scale cosmological simulations to better understand how black holes grow and evolve with galaxies in the early Universe. Much of DeGraf's work involves analyzing quasars, very bright objects powered by galaxies' supermassive black holes. Using the McWilliams Center for Cosmology's cosmological simulations, DeGraf showed that the complex evolution of the quasar luminosity function, a statistic that describes the number density of black holes as a function of their luminosity, is ultimately related to how quasars are ignited by galaxy mergers and collisions. DeGraf also used the simulations to predict the clustering of quasars, finding another link between black holes and galaxy mergers.
"Colin presented this work at a major conference and received a signiﬁcant number of inquiries from both theorists and observers who found his results interesting, new and intriguing to the point that they are planning to test some of the predictions with upcoming observations," said Tiziana Di Matteo, associate professor of physics and DeGraf's research advisor.
Additionally, inspired by the massive quantity of data generated from the cosmological simulations he analyzes, DeGraf began collaborating with CMU's Computer Science Department to build an efficient, queryable database that makes the simulation data vastly easier and faster to access.
Wenwen Li, a fourth year Ph.D. student in the Department of Chemistry, creates a variety of functional nano-scale materials using atom transfer radical polymerization (ATRP), a widely used method of creating industrial plastics. For the past three years, Li has focused on designing, synthesizing and characterizing reactive surfactants for ATRP in environmentally-friendly aqueous disperse media. Recently she used her new concept of "dual reactive surfactant" to synthesize nanocapsules- polymer shells that encase empty interiors. Li's nanocapsules can be used to hold and protect substances, such as drugs, until they reach their target, at which point the nanocapsule degrades to release its cargo. Li was selected to present this work at the American Chemical Society's Excellence in Graduate Polymer Research Symposium, which provides recognition to outstanding graduate students in polymer science and engineering. Currently, Li is working on preparing polymer nanoparticles and porous materials for carbon dioxide capture and release, as well as a super-soft elastomer that potentially can be used for specialty adhesives, molded flexible parts and biomedical applications.
"I not only can define Wenwen as a unique chemist but also as a macromolecular engineer who cleverly designs nanostructured materials, carries out precise synthesis, performs detailed characterization and also thinks about potential applications," said Krzysztof Matyjaszewski, the J.C. Warner Professor of Natural Sciences, and Li's research advisor. "Industrial partners are very excited about her research and often ask her for advice on how to prepare nanostructured functional materials."
The Astrid and Bruce McWilliams Fellowship in the Mellon College of Science was established in 2007 by alumnus Bruce McWilliams, president and CEO of SuVolta and a Carnegie Mellon University trustee; and his wife, Astrid McWilliams, to support graduate students conducting leading-edge research in emerging fields such as nanotechnology, biophysics and cosmology. It provides tuition, stipend and fees for up to one year of graduate study, as well as $1000 for conference travel or other research expenses.