One sunday afternoon you discover a new property of fluid particles, which you decide to name: the scotty (s, a vector field). write an expression for the total rate of change of a fluid particle's scotty in terms of an eulerian velocity field assuming steady flow

Awall of 0.5m thickness is to be constructed from a material which has average thermal conductivity of 1.4 w/mk. the wall is to be insulated with a material having an average thermal conductivity of 0.35 w/mk so that heat loss per square meter shall not exceed 1450 w. assume inner wall surface temperature of 1200°c and outer surface temperature of the insulation to be 15°c. calculate the thickness of insulation required.