Fine particles strain

The range of variability in feldspar weathering rates due to fine particles, strained surfaces, defects and dislocation outcrops, and surface layers is too small to account for the... 

In this definition, ps and pt are the solid and fluid densities, respectively. The characteristic diameter of the particles is ds (which is used in calculating the projected cross-sectional area of particle in the direction of the flow in the drag law). The kinematic viscosity of the fluid is vf and y is a characteristic strain rate for the flow. In a turbulent flow, y can be approximated by l/r when ds is smaller than the Kolmogorov length scale r. (Unless the turbulence is extremely intense, this will usually be the case for fine particles.) Based on the Stokes... 

Nonsettling slurries are formed with fine particles or plastics or fibers. Although their essentially homogeneous nature would appear to make their flow behavior simpler than that of settling slurries, they often possess non-Newtonian characteristics which complicate their flow patterns. In Newtonian flow, the shear stress is proportional to the shear strain,... 

Thus, experimental studies relating dissolution rates to defect concentrations are needed. This has been done recently in two different types of experiments where the importance of line defects has been measured. Casey et al. (1988) and Holdren et al. (1988) have measured the rate of dissolution of rutile and labradorite powders that were shocked with an explosive charge to induce a high density of dislocations (> 1011 cm-2). Concurrently, in order to avoid artifacts due to fine particles, Schott et al. (1989) have performed with the rotating disc apparatus dissolution runs of single crystals of calcite in which dislocations were induced in a constant-strain apparatus. Examples of the results are shown in Fig. 15. Surprisingly, it can be seen that dislocations have only a small effect on the dissolution rates the dissolution rates of samples with over 6 order of magnitude in dislocation density differ only by a factor less than 3. 

Definition of Suspension. The rheology of suspensions deals with how suspensions respond to an applied stress or strain. The term suspension refers, in general, to dispersions of solids in fluids, although the term aerosol is conventionally used to refer to dilute suspensions of fine particles in a gas and the term emulsion is used to identify (concentrated) suspensions of particles in a gas or liquid in the field of fluidization. However, emulsion is conventionally defined as the dispersion of a liquid in another (immiscible) liquid. In a broader sense, emulsions are also considered as suspensions. In this chapter, we deal mainly with suspen-... 

Rather peculiar to the rubber industry is the use of the fine particle size reinfordng fillers, particularly carbon black. Fillers may be used from 50 phr to as high as 100-120 phr or even higher proportions. Their use improves such properties as modulus, tear strength, abrasion resistance, and hardness. They are essential with amorphous rubbers such as SBR and polybutadiene that has Kttle strength without them. They are less essential with strain-crystallizing rubbers such as NR for many applications but are important in the manufacture of tires and related products. 

There is no filler reinforcement of the polyurethane akin to the reinforcement which takes place when reactive or particulate fine particle size fillers are added to non-strain-crystallizable millable elastomers. Fillers in polyurethane reduce strength approximately in proportion to their volume they too, however, increase stiffness and hardness and are cheaper to use for this purpose than additional diisocyanate which gives the same result through hard-segment increase. 

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