Mechanical properties compact body

The mechanical properties of a material play an important role in powder flow and compaction by influencing particle-particle interaction and cohesion, that is to say, by influencing the true area of contact between particles. For example, Hertz [26] demonstrated that both the size and shape of the zone of contact followed simply from the elastic properties of a material. Clearly then, the true area of contact is affected by elastic properties. From the laws of elasticity, one can predict the area of contact between two elastic bodies. More recent work has demonstrated, however, that additional factors must be taken... 

The need for ceramics with improved mechanical properties has led to tremendous interest in methods for preparation of superior powders. In particular, many studies have examined methods for making monodisperse particles from solution. This is based on the argument that the ideal powder should be pure, stoichiometric, dense, equiaxed (i.e., spheroidal), and nearly monodisperse. Uniform particle size is said to facilitate preparation of stable dispersions, as well as dense, uniform powder compacts (76]. However, if the particles are well dispersed, a denser body can be made with a range of particle sizes, as the smaller ones fit into the spaces between the larger ones. It is sometimes argued that the best sintering... 

In the first part of this introductory section, we summarize the main collective phenomena acquired by the dipolar exciton from the lattice-symmetry collectivization of molecular properties. The crystal is considered as an assembly of electrically neutral systems, the molecules, physically separated from each other and in electromagnetic interaction. This /V-body problem will be treated quantum-mechanically in the limit of low exciton densities. We redemonstrate the complete equivalence of this treatment with the theories of Lorentz and Ewald, as well as with the semiclassical approximation. In Section I.A, in a more compact but still gradual way, we establish the model of the rigid lattice of dipoles and the general theory of low-exciton-density systems in interaction with the radiation field. Coulombic excitons, photons,... 

Clearly, the boundary conditions in three-body dry friction are much more difficult to express than in lubrication. A parallel analysis of powder rheology, which would consider both the changes in properties brought about by non homogeneous compacting and the different forms of velocity adaptation would lead to similar conclusions. Nevertheless, the differences observed in the modelling should not hide the basic similarities in the mechanics of both subjects which are centered on load—carrying and flow. 

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