Measurements and modeling of LWIR spectral emissivity of contaminated quartz sand
The fundamental understanding of effects of liquid contaminants on the longwave infrared spectral emissivity of surfaces contaminated is desirable. This research describes modeling and longwave infrared spectral emissivity measurements for samples of SiO2 (sand) with and without 0.3% (by weight) of SF96 (poly dimethyl siloxane) oil. Two different sand particle size ranges were considered. The modeling was performed using a microscattering code and the empirical emissivity measurements were made outdoors using a D&P Instruments Model 102F MicroFTIR non-imaging spectrometer. The data were calibrated and processed to retrieve the spectral emissivity. General observations included a significant increase in emissivity in the 8 to 9 and 12.5 to 13 micron regions due to the presence of the SF96. The comparison between the modeled and measured emissivities shows a consistent trend and significant separability between the spectral emissivity of sand with and without the SF96 present.