Microscopy counting particle size measurement

When the first PSA conference was held 1966, microscopy was being used, together with a scanning flying spot technique to take the tedium out of particle size measurements. During the next PSA conferences [1970, 1977] there was a steady decline in the scientific papers presented using this technique for counting and... 

Electron and optical microscopies. Counting the particles and measuring their sizes can be done by optical or electron microscopy, the former for particles with diameters from 0.4 /im to several hundred microns,... 

Particle size is an important property with respect to the sensory quality of chocolate, and in chocolate manufacture. It can be measured using laser light diffraction spectrophotometry (see Section 22.2.11.2), and by a variety of other means such as micrometry, microscopy, wet sieve fractionation, sedimentation and Coulter counting (Minifie, 1999). 

As a consequence of the difference in counting technique, a shift of measured algae size to smaller values than those determined by microscopy was observed. With each algae species corresponded a typical particle size distribution plot which could be considered as a fingerprint size distribution of that particular planktonic organism. Various algae species were identified with their... 

Microscopy provides the unique advantage that it can measure both particle shape and particle size. Its disadvantage is that compared to other methods, only a small number of particles are counted and that the result may therefore be accompanied by a large statistical error Automatic image processing reduces this problem to some extent. 

Impactor Characteristics. The impactor characteristics can be calculated if the densities of the particles are known. However, since this study was only for the size-fractionation of particles, the distribution was measured by optical microscopy. Ambient air was sampled for 1 hr and the particles were collected on glass slides. The particles were matched to the size circle on the calibrated Porton graticule. Approximately 100 particles were counted on each stage and the size distributions were generated. 

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