Using the energy band model of Si, depict a. A free electron
b. A hole
c. Donor sites
d. Acceptor sites
e. Freeze-out of all electrons at donor sites when TT = 0 K
f. All ionized donors at room temperature (300 K)
g. Freeze-out of all holes at acceptor sites when TT = 0 K
h. All ionized acceptors at room temperature (300 K)

Give heat transfer applications for the following, (i) gas turbines (propulsion) ) gas turbines (power generation). (iii) steam turbines. (iv) combined heat and power (chp). (v) automotive engines

Items are similar to the free issue items, but their access is limited. (clo5) a)-bin stock items free issue b)-bin stock controlled issue c)-critical or insurance spares d)-rebuildable spares e)-consumables

Ahe-xe mixture containing a 0.75 mole fraction of helium is used for cooling electronics in an avionics application. at a temperature of 300 k and atmospheric pressure, calculate the mass fraction of helium and the mass density, molar concentration and molecular weight of the mixture. if the cooling capacity is 10 l, what is the mass of the coolant?