Tensile results showed 17.6% improvement in tensile strength (26 MPa), 21% toughness (1001 J/[m.sup.3]), 22.8%

critical shear stress (25.074 MPa) and 11% thermal diffusivity (2.065 x [10.sup.-7] [m.sup.2]/s) compared with the respective properties of eutectic SnAg.

Because the higher mass fraction of paste is considered as non-Newtonian fluid, the rotator would not rotate unless stress exceeds the

critical shear stress. Several factors are investigated in the experiment with uniform design.

The transition occurs at a

critical shear stress, [[sigma].sup.*], above which the slope of the viscosity is described by a power law index, n, such that the viscosity is modeled as:

However, the

critical shear stress required to activate the GB migration is 0.65 GPa, and the peak stress in each migration cycle reduces gradually to a convergent value ([approximately equal to] 0.25 GPa) with the progress of the shear strain, as shown in Figure 4(c).

In the above equation, [[tau].sub.cr] refers to the elastic

critical shear stress in the web, [[sigma].sup.y.sub.t] the membrane stress in the web in post-critical stage, b, web panel width, c, distance between the hinges formed in the flange, d, web depth, t, web thickness, [M.sub.pf], plastic moment of the flange and [theta], the angle of inclination of the tensile membrane stress [[sigma].sup.y.sub.t].

Relative shear stress is defined as the ratio of the force of friction acting on the substrate (shear stress) to the frictional force required to set a given size of particles in motion (

critical shear stress; Morales et al., 2006).

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.

For a more detailed and quantitative explanation of SH stability, one would have to consider the erosive capacity of the flow (indexed by the bed shear stress, [[tau].sub.b]) relative to the resistance of the bed to erosion (indexed by the

critical shear stress for erosion, [[tau].sub.e]).

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. Melt fracture is a form of flow instability that initiates in the flow channel and further develops downstream of the die lips in the air gap.

If the shear rates reach a value above the

critical shear stress point, the primary bonds in the material can be jeopardized.

However, fillers and additives may block the effect of the processing aid and reduce the

critical shear stress to unacceptable levels.

It has long been realised that different threshold methods give different values of the

critical shear stress for initiation of grain motion.