A public water utility is trying to decide between two different sizes of pipe for a new water main. A 250-mm line will have an initial cost of $155,000, whereas a 300-mm line will cost $210,000. Since there is more head loss through the 250-mm pipe, the pumping cost is expected to be $3000 more per year than for the 250-mm line. If the lines are expected to last for 30 years, which size should be selected on the basis of a present worth analysis using an interest rate of 10% per year

The temperature of air decreases as it is compressed by an adiabatic compressor. a)- true b)- false

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?

A2-m rigid tank initially contains saturated water vapor at 100 kpa. the tank is connected to a supply line through a valve. steam is flowing in the supply line at 600 kpa and 300 c. the valve is opened, and steam is allowed to enter the tank until the pressure in the tank reaches the line pressure, at which point the valve is closed. a thermometer placed in the tank indicates that the temperature at the final state is 200°c. determine (a) the mass of steam that has entered the tank (b) the amount of heat transfer.