Cooling shear-sensitive

During the production of paint, it is important to keep control of the temperature. Due to the high shear forces a substantial amount of heat is produced especially in the pearl mill. Some ingredients in the paint are sensitive to heat, e.g. solvents which will have the risk to flash off. Therefore additional cooling is normally needed in this operation. Figure 9 shows a flow diagram of paint production in a factoiy. 

Figure 6.21 shows the wall shear parameter /" required to evaluate the local skin friction coefficients by Eq. 6.106 or 6.108. These curves apply for the case where ts = 1. The doublevalued nature of /" for a cooled surface (/ = 0) for PP near separation (fZ = 0) is evident. Generally, /" is more sensitive to variations in Pp for a hot surface. In fact, for cold wall conditions (Iw = 0), the variation of f" with PP for PP > 0 is quite modest. Also, a cooled surface tends to retard separation that is, /" = 0 at a smaller value of Pp. 

A material s sensitivity to shear and temperature produces varying levels of shear. While melt travels fastest in the center of the channel, shear is highest near the wall. Cooling effects are also greatest near the wall, producing a melt temperature differential as great as 50 C in the melt channel. 

Again, the SFM can be used to study the phase behavior of confined ultrathin films by applying shear modulation. The time delay, also called phase shift, between the input disturbance and the response signal can be simultaneously recorded in addition to the amplitude response. While the amplitude response is primarily sensitive to changes in the shear modulus, the origin of the time delay is fundamentally different and is only dependent on the viscosity of the material. In order to control on the sample temperature, the SFM has to be combined with a heating/cooling device that allows one to maintain the tenq)erature around RT. 

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