The function of the oil separator in vapour compression refrigerator is (a) lubricate the compressor (b) reduce heat transfer efficiency (c) prevent oil being carried to condenser (d) none of the above

Which of the following controllers anticipates the future from the slope of errors over time? a)-proportional b)-on/off c)-integral d)-derivative.

Consider airflow over a flat plate of length l = 1.5 m under conditions for which transition occurs at le = 0.9 m based on the critical reynolds number, re,e = 5 x 10. evaluating the thermophysical properties of air at 400 k, determine the air velocity. (hint: use the tables to find the properties of air)

On solidification from a melt, the polymer polyethylene forms a semi-crystalline spherulite structure. (i) sketch an individual spherulite and label the amorphous and crystalline regions. (ii) draw a schematic to show the changes in specific volume with temperature during cooling from the melt, comparing it to the theoretical extremes of fully crystalline and fully amorphous (indicate tm and tg)