Table 8.1 SI base units for the seven fundamental dimensions.

Table 8.2 A selection of derived dimensions and their units commonly encountered in food science.

Table 8.3 SI unit prefixes.

Figure 8.1a Constant force, F and velocity, v acting along the same line; the particle trajectory (- - - - -) will continue to be linear.

Figure 8.1b Constant vertical force F acting perpendicular to velocity v; the particle trajectory (- - - - -) will be parabolic.

Figure 8.1c Constant force F acting towards a fixed point ‘o’ and perpendicular to velocity v; the particle trajectory (- - - - -) will be a uniform circular path. F is known as centrifugal force.

Figure 8.1d Variable force proportional to its distance from a fixed point ‘o’; the particle trajectory (- - - - -) will be a simple harmonic motion with amplitude ‘a ’.

Figure 8.2a Longitudinal wave illustrated by the horizontal oscillation of a spring (direction of wave propagation is left to right).

Figure 8.2b One complete cycle of a transverse wave (direction of wave propagation is left to right, and direction of particle oscillation is vertical).

Figure 8.3 Spectrum of electromagnetic radiation.

Figure 8.4 Mass balance over a control volume.

Figure 8.5 Flow through an arbitrary conduit between system conditions 1 and 2 (Equation 8.4).

Figure 8.6 Commonly observed relationships between shear stress and shear rate. A, B and C represent flows illustrated by the power law model: τ = kγn; A represents Newtonian flow where n = 1; B represents shear thinning or pseudoplastic flow where n < 1; and C represents shear thickening or dilatent flow where n > 1. Line D represents what is commonly known as Bingham plastic flow, where the fluid must experience a minimum shear stress (or yield stress) τ0 in order to commence flowing; a behavior similar to Newtonian flow is observed at shear stress values greater than τ0.

Figure 8.7 Thixotropic behavior – due to continuous structural breakdown during the ramp test, viscosity progressively decreases, e.g. mayonnaise, gelatins, etc.

Figure 8.8 Maxwell’s spring and dashpot model for viscoelasticity.

Figure 8. 9 Wetting of liquids on a solid surface Figure 8.9 Wetting of liquids on a solid surface. The angle made by the tangent with the surface, measured anticlockwise, is known as the contact angle: (a) the liquid significantly wets the solid and the contact angle is very low (approaches zero in case the liquid is highly wetting), (b) the liquid is only partially wetting, and (c) the liquid does not wet the surface.