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Microscopic Measurement of Particle Size

Microscopic Measurement of Particle Size. Reading: Chap 20. Q: How do you determine this particle’s size?. Equivalent sizes of Irregular Particles ( 2-d ) Martin’s diameter: Feret’s diameter: Projected area diameter:. Q: Orientation?. Calibration. Porton Graticule

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Microscopic Measurement of Particle Size

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  1. Microscopic Measurement of Particle Size Reading: Chap 20 Q: How do you determine this particle’s size? • Equivalent sizes of Irregular Particles (2-d) • Martin’s diameter: • Feret’s diameter: • Projected area diameter: Q: Orientation? Aerosol & Particulate Research Lab

  2. Calibration Porton Graticule (printed on eye piece) Stage Micrometer (calibration standard printed on glass slide): distance between the smallest lines is 10 mm. A-F is 200 times of d0. Aerosol & Particulate Research Lab

  3. Stratified Counting Many aerosol size distributions are skewed, and relatively few large particles are present. Counting a meaningful number of large particles involves counting unnecessarily large numbers of small particles Q: How to avoid it? Aerosol & Particulate Research Lab

  4. Volume Shape Factor Projected area diameter Equivalent volume diameter Shape factor can also be defined for surface area. Aerosol & Particulate Research Lab

  5. Spreading Factor Liquid aerosol particle are spherical when airborne, but they spread out to form a lens-shaped droplet when collected on a glass slide Q: How to reduce the spreading? Airborne size On slide http://www.freepatentsonline.com/6702425-0-large.jpg Aerosol & Particulate Research Lab

  6. Q: How long is FL’s coastline? Degussa P25 TiO2 particles TI 1243 Aerosol & Particulate Research Lab

  7. Turbulence Borders of clouds and smoke plumes Geometry of lung airways Aerosol & Particulate Research Lab

  8. Fractal Dimension Self-similarity at different levels of magnification L: total length : step size Df: fractal dimension Q: Df = 1? 2? 3? For agglomerates, Npp: Number of primary particles Rg: radius of gyration (rms average distance the particle’s mass is from its center of mass) dpp: diameter of primary particles Aerosol & Particulate Research Lab

  9. http://en.wikipedia.org/wiki/Diffusion-limited_aggregation Animation1 Animation2 Agglomerates formed by different mechanisms Q: How to change from compact-solid to fluffy? Smoke, Dust and Haze, Friedlander, 2000 Aerosol & Particulate Research Lab

  10. Reflection Aerosol & Particulate Research Lab

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