6] proved for a SBR compound that wall slip was always observed at low temperature (70[degrees]C), whereas above 110[degrees]C, it occurred only above a critical shear stress
Mean shear stress was compared to the estimate of critical shear stress
for the median particle size to develop an estimate of relative shear stress for the entire mussel bed.
cr] refers to the elastic critical shear stress
in the web, [[sigma].
Thus, the specific objectives of this study were to (i) determine the interrill and rill erodibility and critical shear stress
of the WEPP model for three clayey Australian soils and compare them to values estimated by WEPP; and (ii) characterise settling velocity of soil aggregates and eroded sediment.
Another challenge when extruding fluoropolymer films is their tendency to develop melt fracture at relatively low shear stress values, referred to as critical shear stress
However, fillers and additives may block the effect of the processing aid and reduce the critical shear stress
to unacceptable levels.
The transition occurs at a critical shear stress
The critical shear stress
and viscosity of Portland cement paste is affected by the form and fineness of the particles of the active mineral admixture and interaction of sodium silicate solution with polycarboxylatether superplasticizer.
When compounds based on strain crystallizing rubbers are extruded at a rate which is above the critical shear stress
for these elastomers, then strain induced crystallization begins and appearance problems result (ref.
The thinner layer tends to accelerate; if it accelerates more than 300% it will exceed the critical shear stress
of most polymers, causing the instability.
They also found that complete dispersion occurs at or above a critical shear stress
that depends on the flow structure.
Melt fracture can be reduced or eliminated by streamlining the die flow channel, reducing shear stress in the land region, using a processing aid, adding die-land heaters, operating above the critical shear stress
for melt fracture (known as "super extrusion"), or adding ultrasonic vibration--a little known but highly successful technique.