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Determine (a) the minimum temperature of the cycle, (b) mass flow rate (m) for a refrigeration rate of 1 ton and (c) the COP. (d) What would the COP be if the adiabatic efficiency increased to 85%?
An insulated piston-cylinder device initially contains 9.647 lb of air at 20 psia and 60ºF. Determine the change in entropy of the air using a variable heat capacity in units of Btu/R. Please sho
How many horsepower does the crane motor exert during the lift? If the crane engine is running at 2000 rpm, how much torque is the motor exerting?
A truck engine delivers 50hp(total) to the truck's (two) rear axles. The truck has 36'' tires and is travelling at 60 mph. What is the torque exerted on each axle?
Draw the temperature dependence (line) of the vacancy concentration on a plot, making sure to label the axes.
A material that you are working with has a band gap of 4 eV but it is opaque (doesn'ttransmit light) because it contains many pores. Why do materials tend to expand with temperature?
Determine: (a)the force sustained by the matrix phase, (b)the modulus of elasticity of the compos- ite material in the longitudinal direction, and (c) the moduli of elasticity for fiber and matrix
Determine for the cycle: (a) the mass flow rate of steam entering the first stage of the turbine, in lb/h. (b) the rate of heat transfer, in Btu/h, to the working fluid passing through the steam gen
A cube is originally at 100 degree. From t = 0 on, the faces are held at 0 degree. Find the time-dependent temperature distribution.
The vacancy formation energy in a particular metal is 0.5 eV. Calculate the concentration of vacancies at 400 oC
A material that you are working with has a band gap of 4 eV but it is opaque (doesn't transmit light) because it contains many pores. Explain the mechanism for low light transmission in this materia
Determine (a) the net power developed in kW (b) the back work ratio, and (c) the thermal efficiency of the cycle . You may assume air to behave like an ideal gas.
Then 1000 Btu per lb of air of heat is added to the system while the pressure remains constant. Determine the change in entropy of the air using a variable heat capacity in units of Btu/R.
Air enters an adiabatic turbine at 408ºC and 1.3 MPa and leaves at 56 kPa. If the isentropic efficiency of the turbine is 92%, what is the actual exhaust temperature at the outlet in ºC?
Consider oxygen at 100 bar and specific volume of 0.08. Calculate the temperature T using the Van der Waal's equation of state.
Sample B is dry, but the density is the same as that of sample A. Assuming air to be an ideal gas, determine the temperature of sample B.
A laboratory test shows that the saturation pressure at -31 deg C is 0.9 bar and the saturation pressure at -29 deg C is 1.1 bar. If the mass flow rate of refrigerant is 0.01 m^3/s, find the refrige
Determine (a) the compressor power, in kW, (b) the refrigerating capacity, in tons(1 ton of refrigeration=3.52 kW), and (c) the coefficient of performance. Show the cycle on a T-s diagram.
Nitrogen at 900kPa and 300oC is expended adiabatically and reversibly in a closed system to 100kPa. Determine the minimum nitrogen temperature after the expansion.
The turbine isentropic efficiency is 0.75. Calculate the efficiency of the plant. If the unit produces 12.5 MW, what is the steam flow rate?
Estimate the energy that a runner expends to overcome aerodynamic drag while running a complete marathon race. This expenditure of energy is equivalent to climbing a hill of what height?
The moist air is then passes through the heating unit. In the heating unit the moist air is heated to 24 oC without adding any moisture. Show the processes on a schematic psychome
Determine the minimum temperature at state 2 and the corresponding minimum power input required by the compressor.