Fragmentation of particles

It is for the above reasons that rejuvenation of supported metal catalysts is typically performed in oxidizing atmospheres. However, redispersion mechanisms may be much more complex than indicated since fragmentation of particles may also occur during the thermal treatments in oxidizing atmospheres (see subsection C). 

Various studies about processes where the Smoluchowski equation is applicable have recognized that fragmentation of particles could be important because the possibility of breakup increases as clusters grow [14-17]. Under these conditions a steady-state particle size distribution as t-+Qo is possible, in agreement with the observations by Fuentes [5-7]. 

FIG. 20-80 Heckel profiles of the unloaded relative compact density for (1) a material densifying by pure plastic deformation, and (2) a material densifying with contributions from brittle fragmentation and particle rearrangement. 

Figure 8.26. Snapshot of particle positions after two-dimensional molecular dynamic expansion fragmentation experiment. From Holian and Grady (1988).

Plasma is a state of matter consisting of neutral excited radicals and ionic particles or fragments of molecules and also comprising electrons and photons. If a solid... 

The formation and fracture of these junctions leads to the transfer of small fragments of material from one surface to another and finally, after many such events, the release of a year particle often in a highly oxidised state. Such a wear process is common to most sliding systems and can undoubtedly occur during fretting movements, especially if the slip amplitude is large. However, many fretting situations occur where the amplitude of slip is very small and perhaps even comparable to the dimensions of a... 

Plasticized white phosphorus (PWP) was found to be the most promising development for control of the fragmentation of P and pillaring of die smoke. It consists of an intimate mixt of granulated WF in a viscous rubber soin. The material burns more slowly and the particles... 

Atomic nuclei are extraordinary particles. They contain all the protons in the atom crammed together in a tiny volume, despite their positive charges (Fig. 17.1). Yet most nuclei survive indefinitely despite the immense repulsive forces between their protons. In some nuclei, though, the repulsions that protons exert on one another overcome the force that holds the nucleons together. Fragments of the nucleus are then ejected, and the nucleus is said to decay. ... 

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