Friction energy, dissipation

Plastic energy dissipation and frictional energy dissipation, in that order of importance, where compacted polymer particulates are relentlessly deformed by twin rotor devices, which rapidly raise their temperature and create regions of melts. 

On the other hand, we discussed and presented in physical terms the very powerful melting mechanisms resulting from repeated, large deformations, forced on compacted particulate assemblies by twin co- or counterrotating devices. These mechanisms, which we refer to in Section 5.1, are frictional energy dissipation (FED), plastic energy dissipation (PED), and dissipative mix-melting (DMM). 

Application of the conservation of momentum to the steady flow of a fluid in a uiuform conduit with any arbitrary cross-sectional shape results in an expression for the momentum due to wall drag (or the equivalent frictional energy dissipation) of the form... 

Note If the material consists of a solid matrix interspersed with a continuous liquid—as is the case for most gels—deformation will always lead to flow of the liquid with respect to the matrix. This causes frictional energy dissipation, hence a finite value of G" and a finite tan 8. Nevertheless, the system may have a perfect memory, i.e., a response like that in Figure 5.8b. In other words, such a matrix may be called viscoelastic without showing any flow. To be sure, many gels do show some flow upon applying a stress. 

As mentioned above there are three sources of energy to melt polymer pellets or powders (i) frictional energy dissipation (FED), (ii) PED, and (iii) VED. When the... 

The AFM probing of polymeric surfaces can, besides imaging the surface, also produce a number of anomalies. Surface contaminants, such as those caused by adsorbed polar molecules, were found to cause significant perturbations on the images produced. From the calculations, it appears that when the AFM tip encounters a polar defect, it is initially attracted (phenomenon) and becomes trapped for a short period of time. This type of stick-slip phenomenon leads to an enhanced frictional energy dissipation which, in turn, causes an increase in the surface temperature of both the AFM tip and the polymer surface. The increase in temperature can subsequently induce rotational defects in a polymer chain and ultimately cause deformations on a long time-scale. 

Intermittent motion arises from an interaction between the machine and the frictional energy dissipation process 38,39. The latter includes the static and kinetic friction of the contact. 

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