To avoid any high-speed imbalance in a rotating shaft; it needs to have a variance of its diameter below 0.0004 mm2. The shaft diameter has been measured at 16 equally distributed locations, with a standard deviation of 0.018 mm. (a) Determine the confidence interval on the variance of the diameter along the shaft with a 95% confidence level.
(b) With a confidence level of 95%, is this shaft acceptable to the customer? (That is is the variance in diameter along the shaft below 0.0004 mm2?)
(c) Answer the questions in Parts (a) and (b) if five measurements are done and the same standard deviation is calculated.

Amass of m 1.5 kg of steam is contained in a closed rigid container. initially the pressure and temperature of the steam are: p 1.5 mpa and t 240°c (superheated state), respectively. then the temperature drops to t2= 100°c as the result of heat transfer to the surroundings. determine: a) quality of the steam at the end of the process, b) heat transfer with the surroundings. for: p1.5 mpa and t 240°c: enthalpy of superheated vapour is 2900 kj/kg, specific volume of superheated vapour is 0. 1483 m/kg, while for t 100°c: enthalpy of saturated liquid water is 419kj/kg, specific volume of saturated liquid water is 0.001043m/kg, enthalpy of saturated vapour is 2676 kj/kg, specific volume of saturated vapour is 1.672 m/kg and pressure is 0.1 mpa.

Steel is coated with a thin layer of ceramic to protect against corrosion. what do you expect to happen to the coating when the temperature of the steel is increased significantly? explain.

Which of the following components of a pid controlled accumulates the error over time and responds to system error after the error has been accumulated? a)- proportional b)- derivative c)- integral d)- on/off.