At what distance ‘X’ will the carbon concentration in a steel specimen be 0.70 wt. % after 10h at 1100 0C, if the starting composition was 0.35 wt. % C and the surface concentration is 1.35 wt.% C?

how do you get x/2sqrt(DT)=0.66085?

Carbon Dioxide is being generated in an occupied space. Each person breathe out carbon

dioxide at the rate 0.0107 cfm. Outdoor air with CO2 concentration of 280 ppm is being

supplied to the space at the rate of 6000cfm. It is desired to keep the concentration level of

CO2 in the space below 1000 ppm. Assuming the room is complete mixing condition,

determine how many person could occupy the room and not exceed the desired CO2 level.

(1 ppm = 1 part per million = 1Å~10-6 per unit volume)

The critical dimension on a machined hole must be 0.5025 in. The machining process can reliably create holes with a known standard deviation of 0.005 in. A random sample of 15 holes has an average diameter of 0.5062 in.

(a) With 97.5% confidence can you conclude that the mean hole diameter is larger than 0.5025 in?

(b) At what confidence level would you change your conclusion? What is the term for the alpha value that is associated with that value?

A simple Rankine cycle is operating between the 12.5 MPa on the high pressure side and 9.93 kPa on the low pressure side. The temperature entering the turbine is 550 degrees Celsius. Find the quality exiting the turbine and the overal thermal efficiency.

A.How to manufacture ceramics of complicated dimension features (i.e., cellular, porous, scaffold) since they cannot be machined or cut?

B. How to print metal materials at room temperature? (open questions, think about phase diagram and check periodic table)

I had to teardown a stapler and figure out how all the part wor together, bit cant seem to get how it all works together , like involving the sprngs and everything.

this is the question i need help with:

How do the parts work together? (of a stapler)

This question related to thermodynamics.

With a throtteling valve in a refrigiration system h₁ = h_2.  

If h₁ = h₂ and only pressure is changed by a throttling valve then why can't an ideal gas be used? Why do refrigerants need to be used?

One-quarter kilogram of air is compressed in a piston-cylinder device from 350 K and 150 kPa to 550 K and 900 kPa. Determine

a. The entropy change, in KJ/K.

b. The direction of any heat transfer by using the entropy balance.

c. What-if scenario: If this process occurs adiabatically, is this process reversible, irreversible, or impossible process? Please answer the nature of this process and why.

The tow hitch is held in place by a retaining pin that is designed to fail before the fasteners between the tow package and the vehicle frame fail. The tow package is designed for 6,000lb as applied to ball hitch. You are tasked with designing the shear pin (retaining pin) for the hitch and have been asked to consider towing the trailer through different gradients up to a maximum of 15%. Determine the internal normal and internal shear on the tongue of the hitch (square tube behind the ball) for various gradients between 0% and 15%. Plot these internal loads with respect to increasing gradient.

It is proposed that a model study be carried out on a proposal low-speed airfoil that is to fly at low altitudes at a speed of 50 m/s. If a 1:10 scale model is to be constructed, what velocity should be used in a wind tunnel? Comment as to the advisability of such a test. Would it be more advisable to perform the test in a 20?C water channel? If a water channel study were undertaken, calculate the drag ratio between the model and prototype.

how to calculate forces on cam and follower at various cam speed and angle.Cam and follower with SHM motion.What are the formula available

Quenching is often used in the manufacturing and/or heat treatment of magnesium alloys, aluminium alloys and steels.

Explain why quenching is used for each of these three metals, and explain how this benefits the final mechanical properties.

Outside air at 10 degC, 1 bar and 40% relative humidity enters an air conditioner operating at steady state with a mass flow rate of 1.5kg/s. The air is first heated at essentially constant pressure to 30 degC. Liquid water at 15 degC is then injected, bringing the air to 25 degC, 1bar.

Determine

(a) the rate of heat transfer to the air passing through the heating section, in kJ/s.

(b) the rate of water is injected, in kg/s.

(c) the relative humidity at the exit of the humidification section.

Kinetic and potential energy can be ignored.

Problem 12.87 Text book: Principle of Engineering Thermodynamics, SI Version, 7th Edition Authors: Moran, Shapiro, Boettner and Bailey

In regards to the metal extrusion manufacturing process:

1. How would you ensure that you obtained a fine-grained microstructure in a metal casting? Carefully explain the mechanism/s that lead to the fine grain size.

Materials Engineering Question

Suggest the optimal heat treatment and condition for 0.45 wt.% steel required, to produce what you consider to be the best combination of properties for a “Chef’s Knife”. Explain your answer and use any literature required to justify it.