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Operations Research, Systems Engineering and Industrial Engineering Commons

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Series

2011

Light scattering

Articles 1 - 2 of 2

Full-Text Articles in Operations Research, Systems Engineering and Industrial Engineering

Digital Holographic Imaging Of Aerosol Particles In Flight, Matthew J. Berg, Gorden Videen Jan 2011

Digital Holographic Imaging Of Aerosol Particles In Flight, Matthew J. Berg, Gorden Videen

US Army Research

This work describes the design and application of an apparatus to image aerosol
particles using digital holography in a flow-through, contact-free manner. Particles in an aerosol stream are illuminated by a triggered, pulsed laser and the pattern produced by the interference of this light with that scattered by the particles is recorded by a digital camera. The recorded pattern constitutes a digital hologram from which an image of the particles is computationally reconstructed using a fast Fourier transform. This imaging is validated using a cluster of ragweed pollen particles. Examples involving mineral-dust aerosols demonstrate the technique’s in situ imaging ...


A New Explanation Of The Extinction Paradox, Matthew J. Berg, C. M. Sorensen, A. Chakrabarti Jan 2011

A New Explanation Of The Extinction Paradox, Matthew J. Berg, C. M. Sorensen, A. Chakrabarti

US Army Research

This work presents a new explanation for the extinction paradox and shows that the canonical explanations are incorrect. This paradox refers to the large size limit of a particle’s extinction cross section. It is called a paradox because the geometrical optics approximation, which should be valid in this limit, predicts a cross section that is half of the true value. The new explanation is achieved by formulating the scattered wave in terms of an integral over the particle’s surface where the seemingly unrelated Ewald–Oseen theorem appears in the formulation. By expressing the cross section in terms of ...