A foundry is using a furnace to reheat billets. The furnace maintains a temperature of 1,400°C and is losing heat from a 0.3 m x 0.6 m opening for the billets to enter the furnace. If the ambient temperature is 27°C with an h = 10 W/m2-K, and treating the opening as a blackbody (emissivity of 1) determine the radiation heat loss in W.

Thermal stresses are developed in a metal when its a) initial temperature is changed b) final temperature is changed c) density is changed d) thermal deformation is prevented e) expansion is prevented f) contraction is prevented

Consider a large isothermal enclosure that is maintained at a uniform temperature of 2000 k. calculate the emissive power of the radiation that emerges from a small aperture on the enclosure surface. what is the wavelength ? , below which 10% of the emission is concentrated? what is the wavelength ? 2 above which 10% of the emission is concentrated? determine the wavelength at which maximum spectral emissive power occurs. what is the irradiation incident on a small object placed inside the enclosure?

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.