An as-wound helical-coil compression spring with infinite fatigue life is needed to resist a dynamic load that varies from 8.0 to 24.0 lbf at 45.0 Hz over a dynamic deflection of 0.3 in. Because of assembly considerations, the solid length of the spring cannot be more than 1.2 in. The spring should have squared and ground ends and is to be made from peened music wire. Upon closure, use a design factor of 1.2 guarding against yielding and a fractional overrun to closure x = 0.15. The fundamental critical frequency should be greater than 10 times the frequency of the dynamic load. The springmaker has the following wire sizes in stock: 0.059, 0.063, 0.072, 0.075, 0.085, and 0.090 in. Select a suitable spring with a fatigue design factor of 1.9 using the Goodman-Zimmerli fatigue failure criterion. Calculate the cost of the wire from which the spring is wound and use it as the figure of merit for your selection

A piston-cylinder has a volume of 1 ft3 and contains a substance initially at 50 °F and 1 atm. The system is then heated until the temperature becomes 300 °F. Determine the total heat added (Btu) and final volume (ft3) assuming the substance is: a) water, b) copper, c) neon, d) air.

Refrigerant-134a enters the condenser of a residential heat pump at 900 kPa and 65^oC at a rate of 0.018 kg/s and leaves at 750 kPa subcooled by 2^oC. The refrigerant enters the compressor at 200 kPa superheated by 3^oC. Determine (a) the isentropic efficiency of the compressor in decimal (up to two decimals), (b) the rate of heat supplied to the heated room, and (c) the COP of the heat pump. Also determine (d) the COP if this heat pump operated on the ideal vapour compression cycle between the pressure limits of 200 and 900 kPa

show the correlation between weight percent carbon, volume percent pearlite, and tensile strength for hot rolled carbon

steels by

1- Looking up the tensile strengths in psi for the following hot rolled AISI carbon steels in matweb.com: 1006, 1010,

1020, 1025, 1030, 1035, 1040, 1045, 1050, 1055, 1060, 1065, and 1070.

2- Calculating the volume percent pearlite for each steel (assume that vol.% pearlite = wt.% pearlite) using the lever

rule and the nominal carbon content indicated by the AISI number.

3- Recording the values in an EXCEL Worksheet that has columns for wt. %C, vol.% pearlite, and tensile strength.

4- Plotting EXCEL graphs of vol.% pearlite versus wt. %C, tensile strength versus wt. %C, and tensile strength

versus vol.% pearlite

1. A black thermocouple measures the temperature in a chamber with black walls. If the air around the thermocouple is at 20°C, the walls are at 100°C, and the heat transfer coefficient between the thermocouple and the air is 15 W /m2·°C, what temperature will the thermocouple read

3. A stainless steel sphere of thermal conductivity 16 W/m · K with a diameter of 4 cm is exposed to a convective environment of 15 W/m2 · K, 20?C. Heat is generated uniformly in the sphere at a rate of 1.0 MW/m3 . Determine the steady-state temperature of the sphere at its center and its surface. Also determine the heat flux at a radius of 1.5 cm.

A bicycle rider is interested in the effects of temperature on air density. A change in temperature will also affect the tire pressure.

a) Write a computer program that calculates air density at atmospheric pressure for temperatures from -10?C to 50?C.

b) Assume that a bicycle tire is inflated to an absolute pressure of 450 kPa at 20?C. Assume also that the volume of the tire does not change with temperature. Write a program to show how the tire pressure changes with the temperature in the same range, -10?C to 50?C.

Prepare a table or graph or both.

Which of the following statements are true regarding AMF/3MF files, in comparison to STL files?

Select all that apply.

a) AMF/3MF files can represent overhangs of greater than 45 degrees, while STL files cannot

b) AMF/3MF files do not require the model to be sliced before printing

c) AMF files can specify multiple materials within the same part

d) The 3MF file format can enumerate the structure of a lattice as a periodic unit, making the file size more compact

A piston-cylinder assembly has initially a volume of 0.3 m3 of air at 25 oC. Mass of the air is 1 kg. Weights are put on the piston until the air reaches to 0.1 m3 and 1,000 oC, in which the air undergoes a polytropic process (PVn = const). Assume that heat loss from the cylinder, friction of piston, kinetic and potential effects are negligible. 1) Determine the polytropic constant n. 2) Determine the work transfer in kJ for this process, and discuss its direction. 3) Sketch the process in T-V (temperature-volume) diagram.

Determine the missing properties for refrigerant R134a (CF3CH2F) for each state given. Show your three step decision process: i.e. 1) list two known properties, 2) determine the phase, 3) look up/interpolate properties from the correct table and show all calculations made for each case.

PART I. For this problem you are allowed and encouraged to look for data or a problem online. What is important in here is to present the analysis.

Identify a quality control problem either in an industrial facility or in a service facility.

Define what the product or service is.

Identify the quality characteristics: dimensions and/or attributes

Identify what are the critical characteristics of your product to pay attention as a quality engineer

Create a fishbone diagram of the problem identified. Include all potential causes of your problem.

Use a Pareto Chart to help you identify the root cause.