Particle definition

Oxidation of SO2 in droplets, which contain various products, detectable in the atmosphere, is the measurement accepted as being real as it approaches atmospheric conditions. Studies upon the oxidation of SO2 in droplets, which contain soot particles, definitely show the effect of carbonaceous material in performing the conversion to SO"4. This process seems to be of relevant importance in polluted areas. As far as liquid phase oxidation of SO2 is concerned, it seems that the uncatalyzed oxidation of SO2 by ozone or hydrogen peroxide is probably the dominant mechanism in the droplet phase. 

Note that this ij-particle definition of annihilation and creation simply reverses the roles of second-quantized operators acting in the (occupied (hole) space, but leaves the those acting in the unoccupied (particle) space untouched. 

Romans et al (1985) stated that to achieve the best particle definition, the raw meat should be ground or chopped at very low temperatures (—4 to -6°C). Mixing and unnecessary handling of the meat should be avoided as much as possible. The cold meat temperature reduces protein extraction and helps to eliminate unnecessary particle deformation. Mixing should be only enough to allow uniform distribution of the curing ingredients and/ or other additives (Pearson and Tauber, 1984). 

The term particle (or grain) size refers to the structural make-up of such substances as granulates, powders, dusts, granular mixes, and suspensions. Knowledge of the particle size, in conjunction with the comminution process, determines such details as grinding efficiency and ultimate product fineness. To establish particle sizes and their distribution within powdered systems, the user can have recourse to a number of different measuring processes designed to indicate, with appropriate particle definition, details of the probable equivalent diameter of a particle. 

It follows that individual measuring methods depend upon particle definition. Particle definitions might include such details as number, length, surface area, mass, and volume, as a result of which one has the choice of using various counting methods - microscopy, image analyzers, laser diffraction, as well as sieving and air classification methods. 

Figure 1. Particle definitions showing mineral growth habits. From the U.S, Bureau of Mines...

---