Breakage of particles

Fig. 5. Estimated characteristic strength of typical biological particles of interest to biotechnology data are based on in-situ measurements of the minimum stresses necessary to cause permanent breakage of particles. For comparison data are shown based on Van der Waals and pendular liquid bridges between two 10-pm particles, 0.01 pm apart...

In most of the previous works dealing with optimisation, the mills were described as perfectly mixed units. In a number of grinding systems, however, mixing and breakage of particles occur simultaneously, so that mixing of the mate-... 

Temperature dependence of the equilibrium CO concentrations and sintering of copper crystallites (the active phase) at elevated temperatures dictate that the LTS stage be operated at the lowest possible temperature. It is common practice to keep the inlet temperature at least at about 20°C above the dew point of the feed gas, which can be as high as 180-200° C. If water condenses on the catalyst, it can lead to breakage of particles and deactivation of the catalyst. 

The average production rate for particles of state (x, r) originating from breakage of particles of all other particles states, considering both internal and external coordinates is frequently given by [94] ... 

Total mass fraction of particles smaller than size resulting from breakage of particles of size Dp ... 

Column collapse by breakage of particles has been studied in detail by Groh (11). He slowly increased the flow through a column packed with silica particles until the bed collapsed. He found that for a given particle size the point of collapse could be described by either the product of linear velocity and viscosity or by the pressure divided by column length. The dependence on particle size was not as clearcut because of experimental noise, but in a good approximation the critical value was proportional to the particle size ... 

The efficiency of these methods may be further increased by the application of ultrasound. Ultrasound techniques are able to combine the breakage of particle agglomerates with an effective mixing of the material components on a molecular level. In combination with mechanical stirring, ultrasound waves were able to successfully disperse carbon nanotubes in epoxy resin. ... 

Size distribution of powdery raw materials,suspensions and xerogels are determined by laser diffraction (size range 1,2-560 pm). Size measurements of powders are performed on either aqueous suspension and dry aerosols (interactions between water and dried panicles can result in breakage of particles). 

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