PHC320H1 Lecture Notes - Lecture 11: Coulter Counter, Scattering, Nasal Spray
24 Mar 2015
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The equivalent sedimentation speed diameter - density of particles and medium and the square of the diameter (stokes diameter). The rate of settling is defined as the distance divided by the time. The volume and the mass, but the surface area also plays a role. The driving force is due to the friction between the liquid and the particle. The surface area is proportional to the diameter squared. The gravitational method, collect same from tube and measure the mass. So, based on stoke"s law, we can calculate the diameter. And, because we get the weight for each fraction, we use the weight average, multipled by the diameter and then we add them together and divide the total weight (so we use the weight average particle size) The laser light vibration can measure larger particles, because the mechanism is based on the diffraction . The light scattering method is also called photos-correlation spectroscopy (pcs) and based on brownian motion.
