The diffusion coefficient of nickel in an austenitic (fcc structure) stainless steel is 10^-22 m^2/s at 500° c and 10^-15 m^2/s at 1000° c. calculate the activation energy (or more precisely, the activation enthalpy) for the diffusion of nickel in this alloy over this temperature range. calculate also the pre- exponential constant do.

Slip occurs via two partial dislocations because of (a) the shorter path of the partial dislocation lines; (b) the lower energy state through partial dislocations; (c) the charge balance.

Machinery that is a key part of the process and without which the plant or process cannot function is classifed as: (clo4) a)-critical machinery b)-essential machinery c)-general purpose machinery d)-none of the specified options.

An air compression refrigeration system is to have an air pressure of 100 psia in the brine tank and an allowable air temperature increase of 60°f for standard vapor compression cycle temperatures of 77 f entering the expansion cylinder and 14 f entering the compression cylinder, calculate the coefficient of performance a. 2.5 b 3.3 c. 4.0 d. 5.0