The accessory drive unit of a large aircraft engine involves an identical pair of 20° full-depth spur gears. The gears have 50 teeth and rotate together at 5000 rpm. The diametral pitch is 12 and the face width 1.5 in. The gears are made of alloy steel, casehardened to 62Rc (680 Bhn). Although the case extends throughout the fillet, it is conservatively decided to use the core hardness of 500 Bhn for calculating bending fatigue strength. The tooth profiles are finished with a fine-grinding operation that gives a degree of precision justifying the use of curve A of Figure 15.24 and the assumption that teeth share the load. The loading involves only very mild shock, justifying the use of Ko = 1.1.

(a). Estimate the horsepower that can be transmitted with 99% reliability, based on tooth bending fatigue.

(b). Estimate the horsepower that can be transmitted for 109 cycles with 90% reliability, based on surface fatigue.

Briefly describe and explain the driving force for the electrochemical crevice corrosion happened in the riveted structure in water, as shown in Figure 17.16 in Callister 9th Ed. Book, use Nernst equation as you see necessary.

Use MATLAB DSOLVE to solve the folloing ODE and plot it:

300x'' + 60x' + 6840 = f(t)

Write a MATLAB function that uses my_sine(x,n) to plot the approximation of the sinefunction from−3π/2 to 3π/2 with increments equal to Δx,where Δx and n(the number ofterms used in the series approximation) should be input arguments of the function andshould be specified by the user.

What is diametral pitch, and why is it an important parameter in a gear mesh?

For the factors / conditions listed, select those that tend to alleviate creep deformation for a metal sample with a random polycrystalline microstructure.

a. Raise the service temperature that the part is exposed to.

b. Substitute the metal for one with a higher melting point.

c. Decrease the applied stress on the metal part.

d. Decrease the average grain size of the metal part.

e. Increase the grain count of the metal part (for a fixed volume).

f. Apply an insulative (non-structural) ceramic coating to the part.

g. Switch to a single crystal or textured polycrystalline microstructure.

Solution for problem one (P1) below:

ME 311 Thermodynamics I 1 Homework 5 Problem from Cengel and Boles 8th Edition

P1) Carbon dioxide flows steadily in a pipe at 3000 kPa, 31 °C, and at a rate of 1.5 kg/s.

Determine the density of carbon dioxide using

(a) the ideal gas law

and

(b) the compressibility chart.

Liquid mercury at 0.5 kg/s is to be heated from 300 to
400 K by passing it through a 50-mm-diameter tube
whose surface is maintained at 450 K. Calculate the
required tube length by using an appropriate liquid
metal convection heat transfer correlation. Compare
your result with that which would have been obtained
by using a correlation appropriate for Pr>= 0.7.

(A) Derive Bernoulli's Equation from Pressure, Kinetic Energy and Potential Energy

(B) Express Bernoulli's equation:

- Per unit mass

-Per unit volume

- In terms of heads

I need a full article on leadership and mechanical engineering two full pages

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Imagine a diverging channel in place of the jet engine. Air enters the channel supersonically and accelerates further in the diverging geometry. The exit velocity is an even faster jet which would provide thrust to the aircraft. In this design no energy is required in the form of combustion. Would this design work? If yes, why, and if not, why not? Use equations to explain your physics based arguments. You can use a quantitative example to make your point.

An adiabatic mixing chamber with operating pressure of 180 kPa is used to mix cold water and hot water. The hot water enters at 80°C with mass flow rate of 4.1 kg/s. The cold water enters the chamber at 39°C and the mixture leaves at a temperature of 45°C. Determine (a) the mass flow rate of the cold water and (b) the rate of entropy generation during this process.  

Concept 1: Does turbulent flow or laminar flow have a greater heat transfer coefficient? Why?

Concept 2: For flow over a flat plate, why does the heat transfer coefficient decrease the greater the distance from the leading edge? (in answering, ignore the effects of flow regime transitions. i.e. assume the flow over the plate is all laminar or all turbulent).

Explain why adding Ti or Si can raise the eutectoid temperature of steels? What is the impact of having higher eutectoid temperature on using heat treatment to obtain Bainite? Use the CT or TTT diagram to explain.