A stainless steel ball (? = 8055 kg/m³ , C_P = 480 J/Kg? K ) of diameter D = 15cm is removed from the oven at a uniform temperature of 350 Degrees C. The ball is then subjected to the flow of air at 1 atm pressure and 30 degrees C with a velocity of 6m/s. The surface temperature of the ball eventually drops to 250 degrees 250 degrees C. Determine the average convection heat transfer coefficient during this cooling process and estimate how long this process has taken. The solution should be h = 25.12 W/m2 C and time = 1425 seconds according to the professor.

Describe the main operating principle of the X-Ray Diffraction (XRD) technique for analyzing the internal structure of powders and bulk solid samples. Use figures to illustrate your answer.

refrences needed

State and explain the different stages involved in refining the grain structure of metallic powders using high-energy ball milling.

Consider a 2.0 MW wind turbine that operates with a capacity factor of 30% (i.e. it produces 5,300 MWh/y). The initial cost is $3.5 million. The project life is 30 years and the salvage value is negligible. Maintenance costs are $50,000/y. The minimum attractive rate of return is 7%. For each of the following cases, determine the present value of the project and whether the cost is justified.

a. Power can be sold to the grid at $0.055/kWh. (ans. -503200, not justified)

b. Power can be sold to the grid at $0.10/kWh. (ans. 2456000 justified)

For a ball bearing made out of plastic inner and outer race and a stainless steel ball, which of these materials is likely to wear? What would the wear pattern be like? Which will eventually fail first?

An example of a superalloy/composites that could be used to build a landing gear for a space rocket like new shepherd(blue origin)

Steam flows steadily through an adiabatic turbine. The inlet conditions of the steam are 4
MPa, 500°C and 80 m/s, and the exit conditions are 30 kPa, 92% quality and 50 m/s. The
mass flowrate of the steam is 12 kg/s. Investigate the effect of the turbine exit pressure on
the power output of the turbine. Let the exit pressure vary from 10 to 200 kPa. Plot (1) T2
vs P2 and 2) Plot the power output (W_dot_T in MW) against the exit pressure (P2 in kPa)
and discuss the results.

a. What is the extensive property of interest/study in the first law of thermodynamics?

b. What three processes can influence the property of interest in an open system analysis of the first law of thermodynamics?

c. What crosses an open system boundary that cannot cross a closed system boundary?

d. Which are additive in nature, intensive properties or extensive properties?

e. Is the rate of change of a property inside a system boundary denoted with a dot or with a time derivative?

f. Is the rate at which a property crosses a system boundary denoted with a dot or with a time derivative?

g. What is the region of space outside of the system called?  

Read the 2008 paper by Spanos et al. “A nonlinear model for top fuel dragster dynamic performance assessment” (attached to this file) as an example. Even if you don’t understand everything in the paper, please try to answer the following questions in your own words after reading it:

Here is a link to the paper:

https://www.researchgate.net/publication/261913459_dragsterSAE

a) What is the general aim of this paper?

b) Did the authors actually test the predictions of their model?

c) Do you think the simulations are reliable? Why / why not?

d) Do you think the authors are racers themselves?

e) Do you recognize some of the concepts we discussed in class and in other courses at ODU?

f) Do you believe you would be able to carry out such a theoretical research project yourself on a different racecar of your interest? If not, what can the university / department / instructor do better to provide you with the necessary skills (assuming you think it would be worthwhile for you to have this type of proficiency)?

Answer the following questions:

a. What is the extensive property of interest/study in the first law of thermodynamics?

b. What three processes can influence the property of interest in an open system analysis of the first law of thermodynamics?

c. What crosses an open system boundary that cannot cross a closed system boundary?

d. Which are additive in nature, intensive properties or extensive properties?

e. Is the rate of change of a property inside a system boundary denoted with a dot or with a time derivative?

f. Is the rate at which a property crosses a system boundary denoted with a dot or with a time derivative? g. What is the region of space outside of the system called?

Consider a flat plate with parallel airflow (top and bottom) characterized by u∞ 5 m/s, T∞ 20°C. Determine the average convection heat transfer coefficient, convective heat transfer rate, and drag force associated with an 2.8-m-long, 2.8-m wide flat plate with a surface temperature of 50°C. Assume the critical Reynolds number is 5x10⁵.

Determine the average convection heat transfer coefficient, in W/m²·K.

Determine the convective heat transfer rate, in W.

Determine the drag force, in N.

Describe the engineering designs associated with vapor space above the tube bundle in a kettle reboiler and liquid levels above and below the tubes.

2. Explain why Charpy impact specimens of steels fractured in the middle of the ductile to brittle transition region fail by brittle fracture in the center and ductile fracture at the edges (See Ref. [10], p. 89).

1. Explain the Betz’s theorem and various terms in the equation