Common practice in chemical processing plants is to clad pipe insulation with a durable, thick aluminum foil. The functions of the foil are to confine the batt insulation and to reduce heat transfer by radiation to the surroundings. Because of the presence of chlorine (at chlorine or seaside plants), the aluminum foil surface, which is initially bright, becomes etched with in-service time. Typically, the emissivity might change from 0.12 at installation to 0.36 with extended service. For a 300-mm-diameter foil-covered pipe whose surface temperature is 90 C, will this increase in emissivity due to degradation of the foil finish have a significant effect on heat loss from the pipe? Consider two cases with surroundings and ambient air at 25 C: (a) quiescent air and (b) a cross-wind velocity of 10 m/s.

identify the stages in the appropriate order in the precipitation hardening of an aluminum alloy

Question 1c (0.5 pts): In a study published in 2016, a team of researchers found that tensile strain caused the valence band of an organic semiconductor to narrow and fall to lower energy levels without affecting the conduction band. What do you think this means for the electrical conductivity of the material when placed under tensile strain? Why do you think this occurs?

For a catapult project I must make a MATLAB code that should make use of the projectile motion equations so for a given input range R (horizontal distance from the catapult to the target), the code outputs the necessary velocity and firing angle of the catapult. I must be able to input ranges: 7ft, 8ft and 9ft and the output of the code should give me the possible velocities and theta of the catapult.

5. Explain how density is affected by crystal shape, i.e., BCC or FCC.

6. Why would you temper material such as steel? If not tempered, how does that influence its likely failure, what will happen?

7. What does a TTT diagram presentation, explain how it is used to determine the material property after cooling.

8. What are the advantages and disadvantages of case hardening and Nitriding?

1. Why are components made from steel or aluminum alloy used on aircraft?

2. For each of the following suggest a part on an aircraft that needs that particular material property: hardness, strength, elasticity, placidity, ductility, toughness, and brittleness.

3. Explain in why exceeding the yield point causes permeant stain, and how that is measured and calculated.

4. What do the temperatures on 1 & 2 of the iron– Carbon phase diagram indicate, shown in the presentation? What is the difference between 3 & 5? Four (4) represents the melted region; will the composition of the alloy be the same?

Thermodynamics

The centrifugal compressor in a refrigeration system operating at steady state conditions, compresses adiabatically 0.1 lbm/s of saturated R-134a vapor at 0°F to 200 psia. Answer the following.

a. Create a schematic representation of your system and draw the boundary you would use to solve the questions in this problem.

b. Represent the process on a T-s diagram.

c. Calculate the minimum work required by this compressor, in hp. Note: the solution to this problem requires interpolations; use your textbook tables. You answer will also be evaluated on its accuracy.

Analytical Solution steps

For a flat plate solar collector, with water as the working fluid, consider a design for heating water from 22°C to 60°C. The temperature of the air and the surroundings is 310 K. The system is designed for a flow rate of 0.03 gpm. The water exhibits fully developed, laminar flow in a 0.05 diameter pipe, with a constant surface flux. The collector plate experiences losses due to convection and radiation, which can be accounted for using a total heat transfer coefficient of 0.02 kW/m2 K. Use a solar resource map to find the annual, average incident solar radiation, G, for Dallas, TX. Assume a black nickel oxide plated metal surface for the collector. Use a heat removal factor of 0.95

Determine the required size of the solar collector.

Consider an ideal Rankine cycle using water with a high-pressure side of the cycle at a supercritical pressure. Such a

cycle has a potential advantage of minimizing local temperature differences between the fluids in the steam

generator, such as the instance in which the high-temperature energy source is the hot exhaust gas from a gas-

turbine engine. Calculate the thermal efficiency of the cycle if the state entering the turbine is 30 MPa, 550°C, and

the condenser pressure is 5 kPa. What is the steam quality at the turbine exit?

A man is pulling a 120 lb wooden box by a rope with a force of 80 lb along a wooden floor. The rope is 45 degrees from the horizontal. The coefficient of of dynamic friction between wood to wood surfaces is Uk=0.45. If the box initially starts from rest, what will the box's (a) acceleration,and (b) velocity after 8 sec? (c) max power and (d) average power. Make sure to have FDB and kinetic diagrams, and unit base vectors.

Q5. State whether the following are true or false with brief justifications:

(i) The maximum thermal efficiency for any power cycle operating between two thermal reservoirs at temperatures T1 and T2 (T1 > T2) is 1- T2/T1.
(ii) Transferring heat from a cold object to a hot object is forbidden according to the Clausius statement of the second law.

(iii) A cycle that does not violate the Kelvin-Planck statement cannot violate the Clausius statement of the second law.
(iv) For a reversible power cycle, if we hold the temperature of the cold reservoir (TC) constant, we can increase the thermal efficiency ? to any value smaller than 1 (100%) by varying TH.

(v) A system interacting with air at different heights in the atmosphere is interacting with only one thermal reservoir, i.e., the atmosphere.

What A laminated steel (E = 200 GPa and ? = 0.3) cylinder consists of a jacket with an inside diameter of 200 mm and an outside diameter of 300 mm shrunk onto a tube with an inside diameter of 100 mm. The initial shrinkage pressure is 25 MPa.
Determine:

a. The maximum tensile stress in the cylinder after it is fabricated subject to an internal pressure of 200 MPa.

b. What and where is the maximum shear stress?

Describe how the capabilities of humans versus machines drive the allocation of functions in human-centered design. Provide examples.

A mixture of 92 kg of ZrO2 with 8 kg of CaO is melted into a liquid at high temperature

. a) On slow cooling, at what temperature will solid first appear?

b) What is the composition of this solid?

c) At what temperature will the sample become completely solid?

c) As the sample continues to cool, at what temperature will a second solid phase begin to precipitate?

d) What is the composition of this solid phase?

e) What is the expected composition and relative amounts of the phases expected to be present at room temperature?