Charles Branham Charles Branham is a Ph.D. student in chemistry working with APL-UW Engineer Brian Marquardt. Charlie's research focuses on novel optical oxygen sensing systems based on vapochromic compounds—phosphorescence transition metal complexes that absorb light and efficiently emit phosphorescence at low energy. The complexes rapidly and quantitatively change the color and/or intensity of their emission spectrum in the presence of specific gases in liquid or air. The fellowship will support his development and optimization of a low-power optoelectronic oxygen sensor package for long-term deployments in various environments. Preliminary research has developed a sensor with an oxygen detection limit in both gas and liquid phases below 50 ppb. The solid state sensor could b used to monitor oxygen concentrations in marine applications (on Seagliders, ARGO floats, moored buoys), industrial applications (on firemen's helmets and NASA spacesuits, or in airplane cabins), and environmental applications (to monitor Hood Canal anoxia, waste water treatment plants, or air quality in mineshafts).   Sam Gooch Sam Gooch is a second-year mechanical engineering graduate student who began working with APL-UW Oceanographer Jim Thomson last fall to develop measurement systems for tidal power resource assessment. The work is supported by the newly established Northwest National Marine Renewable Energy Center, sponsored by the U.S. Department of Energy. The WRF-APL fellowship will support Sam's thesis completion, "Methods and instrumentation for tidal power resource assessment." Sam's research proposal has two major components. The first is a software suite designed to optimize the survey work for resource assessment and turbine siting. The second is a comprehensive hardware package geared specifically towards tidal energy installations. Both will be tested in Admiralty Inlet, where the Snohomish Public Utility District has already obtained federal permits for a feasibility study and pilot installation. This industry partnership will provide an immediate demonstration of the innovative measurement technologies developed by Sam as a WRF-APL Fellow.   Danling Wang Danling Wang is an electrical engineering Ph.D. student working with APL-UW Senior Engineer Antao Chen. The fellowship will support her research to develop sensitive sensors that can rapidly detect trace vapor amounts of nitroaromatic explosives. She is pursuing nano-structured titanium oxide thin film micro sensors that have lower power consumption, higher sensitivity and specificity, faster response, smaller size, and lower cost than existing detection technologies. She discovered recently that nanowires composed of large band-gap semiconductors, such as titanium oxide, show significant changes in their electrical resistance at room temperature when exposed to explosive vapors at part-per-billion concentrations. She is now working to optimize the fabrication of nanostructures with well-controlled and uniformly sized diameter and length, and to understand the fundamental sensing mechanism, i.e., the surface interaction between target gas molecules and titania, as well as the transportation rate of electrons along the nanowires. Sensors based on her research have obvious applications in counter-terrorism and homeland security.