Two plane coaxial disks are separated by a distance l = 0.80 m. the lower disk (a1) is solid with a diame- ter do = 0.80 m and a temperature t1 = 300 k. the upper disk (a2), at temperature t2 = 900 k, has the same outer diameter but is ring-shaped with an inner diameter di = 0.40 m.
a). find the view factor f2
b). assuming the disks to be blackbodies, calculate the net radiative heat exchange between them

Different types of steels contain different elements that alter the characteristics of the steel. for each of the following elements, explain what the element does when alloyed with steel.

For the closed feedwater heater below, feedwater enters state 3 at a pressure of 2000 psia and temperature of 420 °f at a rate of ix10 ibhr. the feedwat extracted steam enters state 1 at a pressure of 1000 psia and enthalpy of 1500 btu/lbm. the extracted er leaves at an enthalpy of 528.7 btu/lbm steam leaves as a saturated liquid. (16) a) determine the mass flow rate of the extraction steam used to heat the feedwater (10) b) determine the terminal temperature difference of the closed feedwater heater

Which one from below is not one of the reasons of planning failures? (clo3) a)-planner is careless. b-planner spend less time in the field but more time on the desk c)-planner is not qualified d)-planner does not have sufficient time to properly plan