Predictive modeling of atmospheric nuclear fallout microphysics.

The capability to predict size, composition, and transport of nuclear fallout enables public officials to determine immediate and prolonged guidance in the event of a nuclear incident. Predictive computer models of fallout can also provide useful insight for nuclear forensic response when detailed radiochemical processes can be reliably included. Current post-detonation nuclear fallout models prescribe particle size distributions empirically or semi-empirically, based on measurements across limited conditions pertaining to tests conducted primarily in Nevada and the Pacific.

Mitigation of PAH and nitro-PAH emissions from nonroad diesel engines.

More stringent emission requirements for nonroad diesel engines introduced with U.S. Tier 4 Final and Euro Stage IV and V regulations have spurred the development of exhaust aftertreatment technologies.

Patterning by Photochemically Directing the Marangoni Effect.

Polystyrene (PS) that has been exposed to ultraviolet light (UV) undergoes partial dehydrogenation of the alkane polymer backbone which increases its surface energy. Exploiting this photochemistry, we exposed polystyrene films to UV light using a photomask to induce a patterned photochemical reaction producing regions in the film with differing surface energy. Upon heating the solid polymer film with the preprogrammed surface energy pattern to a liquid state, the polymer flows from the low surface energy unexposed regions to high surface energy exposed regions.