A refrigerator with R-410a as the working fluid has a minimum temperature of −10°C and a maximum pressure of 1 MPa. Assuming an ideal refrigeration cycle, find the specific heat transfer FROM the cold space, the specific heat transfer TO the hot space, and the coefficient of performance. Will this refrigeration cycle work in an ordinary kitchen?
In: Mechanical Engineering
In: Mechanical Engineering
Explain the concept of the TTT diagram, e.g why is there a “nose”?
How are cooling rates controlled to produce coarse and fine pearlite/bainite?
Applications of low, medium, and high-carbon steels, cast irons, stainless steels
In: Mechanical Engineering
Q1. Describe mechanical properties of stress-strain behavior of a polymer and a plastic (contrast with stress-strain curves of ceramics and metals)
Q2. Describe variation of elastic/relaxation modulus with temperature.
Q3. Describe viscoelasticity and examples of a rubber/elastomer.
In: Mechanical Engineering
•A hydraulic motor has a 22-in3 volumetric displacement. If it has a pressure rating of 1200 psi and it receives oil from a 15 gpm theoretical flow rate pump, find the motor a) speed, b) theoretical torque and c) theoretical horsepower.
In: Mechanical Engineering
In: Mechanical Engineering
Describe how both the X and R or s chart would look if they were under normal statistical control.
In: Mechanical Engineering
A large bank established X-Bar and R charts for the time
required to process applications for its charge cards. A sample of
five applications is taken each day. The first four weeks (20 days)
of data give:
X bar bar = 16 min s bar = 3 min R bar = 7
min
Based on the values given, calculate the centerline and
control limits for the X bar and R charts.
In: Mechanical Engineering
7. When studying a process control chart tracking one variable, what is meant by the statement, "The process is in a state of statistical control"
In: Mechanical Engineering
How do you calculate the factor of safety for a worm in a worm gear drive? I am looking for the mathematical equations to calculate this. Linking outside resources would be much appreciated.
In: Mechanical Engineering
A closed, rigid, 0.40 m3 tank is filled with 15 kg of
water. The initial pressure is p1 = 20 bar. The
water is cooled until the pressure is p2= 4
bar.
Determine the initial quality, x1, and the heat
transfer, in kJ.
In: Mechanical Engineering
For a bicycle, the nominal diameter of the outer race of a ball bearing and the inner surface of the hub is 62 mm. What should be the maximum dimension for the hub if a medium drive hole basis fit is desired? Use a preferred fit.
In: Mechanical Engineering
Compare the yearly greenhouse gas emissions from 1 GWe (gigawatt-electric) power stations powered by natural gas and wind turbines. The energy content of natural gas is 55 MJ/kg, and the electrical converting efficiency is 40%. Wind turbines do not emit CO2 as they harness the wind but emissions do occur during the manufacturing of the turbine. For USA, assume the CO2 emission per GDP is approximately 500 Tonnes / $ 1 million of GDP. For wind turbines, it costs $2 million for a 1 MWe plant, which has an efficiency of 0.3, and the yearly maintenance is approximately 2% of the initial cost. Assume the average lifetime of a wind turbine is 20 years.
In: Mechanical Engineering
For a bicycle, the nominal diameter of the outer race of a ball bearing and the inner surface of the hub is 62 mm. What should be the maximum dimension for the outer race of the ball bearing if a medium drive hole basis fit is desired? Use a preferred fit.
In: Mechanical Engineering
Air enters a compressor operating at steady state at 1.05 bar,
300 K, with a volumetric flow rate of 48 m3/min and
exits at 12 bar, 400 K. Heat transfer occurs at a rate of 8 kW from
the compressor to its surroundings.
Assuming the ideal gas model for air and neglecting kinetic and
potential energy effects, determine the power input, in kW.
In: Mechanical Engineering