Daniel P. Wilson

Exploring surface photoreaction dynamics using pixel imaging mass spectrometry (PImMS)

A new technique for studying surface photochemistry has been developed using an ion imaging time-of-flight mass spectrometer in conjunction with a fast camera capable of multimass imaging. This technique, called pixel imaging mass spectrometry (PImMS), has been applied to the study of butanone photooxidation on TiO2(110). In agreement with previous studies of this system, it was observed that the main photooxidation pathway for butanone involves ejection of an ethyl radical into vacuum which, as confirmed by our imaging experiment, undergoes fragmentation after ionization in the mass spectrometer. This proof-of-principle experiment illustrates the usefulness and applicability of PImMS technology to problems of interest within the surface science community.

High energy large scale blast sound propagation experiments

Atmospheric conditions greatly affect the propagation of the sound. Currently, little information exists regarding the amount of variation in level and spectra of blast noise that is caused by changing meteorological conditions along the propagation path. Available meteorological models accurately predict vertical sound speed profiles only up to the top of the boundary layer. For long-range propagation, this is inadequate. Vertical sound speed profile data and resulting propagation effects will help to better explain the effects of atmospheric refraction in sound propagation. This report detailed the procedures and equipment used to carry out a series of blast noise experiments at White Sands Missile Range, NM and Fort Leonard Wood, MO from 2007 to 2009. The data provided by this large-scale experiment comprise a definitive dataset for the effects of a wide range of meteorological conditions on long-range high-energy blast sound propagation in climate types similar to the majority of continental United States (CONUS) military installations (arid desert and temperate vegetated). The experiment also captured a comprehensive set of meteorological measurements over the duration of the experiments. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. DESTROY THIS REPORT WHEN NO LONGER NEEDED. DO NOT RETURN IT TO THE ORIGINATOR.