Using words and visuals, briefly describe the temperature dependence of stiffness for the following classes of polymers. Explain how the structure and bonding in these materials contributes to the observed temperature-dependent properties (structure-property connections).

Amorphous and semi-crystalline thermoplastics

Elastomers

Thermosets

Architectural plans question: when reading the specifications of construction plans; the specification calls for anchor bolts that meet ASTM standard F1554 Grade 36, do these standards give the size of anchor bolts needed? In general what type of information does ASTM standardize ? (material and sizing?)

An oil at 50C with properties similar to engine oil passes through a 30 cm diameter pipe with an average velocity of 6 m/s. A 200 m long section of pipe passes under a frozen lake with waters at 0 C. The pipe has the same surface temperature as the lake water.

(a) Find the temperature of the oil as it leaves the lake. Neglect the thermal resistance of the pipematerial.

(b) At what rate is heat transferred from the oil?

Lets say I have a second order ODE: mx''+kx+bx'=kz+bz' ( an EOM where m=3000, b=2000, k=50000, and finally z=.01sin(3.5t)).

In Matlab, how would I use the Matlab command ode23 to solve this ode assuming zero initial conditions, range :0-20 seconds.

P5. Coal power plants operate at high temperature of about 600C, whereas a jet engine operates at high temperature of about 1200C. Would you recommend replacing the coal power plant with the jet engine for power production? Justify your answer.

Consider a Kantrowitz-Donaldson diffuser designed for a flight Mach number of 1.8. The entrance area equals 3.0 ft2and the ambient airtemperature and pressure are 500R and 0.8atmosphere. The flow is isentropic everywhere except across the normal shockwave. Determine:(a) the minimum cross-sectional area of the throat such that a normal shock may be stabilized at the entrance, (b) the maximum mass flow, and(c) the maximum stagnation pressure possible at the end of the diffuser (with subsonic flow only in the divergent portion).In each of these optimizations, consider the flight Mach number fixed at the design value while the final pressure (at the end of the diffuser) is allowed to adjust.

A Carnot heat pump moves heat to a warm house at 24°C at a rate of 300kW. The heat is pumped from the outside air at 7°C. What is the power required by the heat pump?

What is the rate of change of entropy for each of the thermal reservoirs (the house, and the outside air)?

Does this heat pump satisfy the second law of thermodynamics increase of entropy principle?

a. A shaft is used to transmit power. What does this mean?

b. Explain the general process of choosing a material for a shaft.

c. Discuss the considerations that must be made when selecting the layout of a shaft.

5. A fluctuating external load of Ppeak = 4500 lb is applied at the bolted joint given in Problem 4.
(1) Find the factor n_f of safety against the fatigue failure using the modified Goodman criterion.
(2) Find the factor n_p of safety using the proof strength line.
(3) Find the factor n₀ of safety against joint separation.
(4) Find the factor n of safety against yielding.

(question 4 for reference)

4. For the assembly similar to the one in Problem 3, the bolt of ½ in-13-UNC-2A grade 8 with rolled
threads is proloaded to 80% of its proof strength. There is a static 1500-lb load applied to the
assembly to separate the joint. It is known that k_b = 1.2x10⁶ lbf/in and km = 8.4x10⁶ lbf/in
(1) Find the load factor nl.
(2) Find the factor of safety against static failure n.
(3) Find the factor of safety against joint separation n0.

What maximum temperature might be expected at the bottom of a well drilled within a relatively high-grade geothermal energy such as Lightning Dock geothermal resource in southwest New Mexico?

Please cite references

(a) Just like the familiar liquid solutions, two metal ions or atoms combine to form solid solution. What are substitutional solid solutions and interstitial solid solutions? Explain with examples and sketches.
(b) How well the solid atoms combine to form solid solutions depends on how many of the Hume-Rothery rules have been violated or not violated. Describe Hume-Rothery rules?

A propane tank with 75 gallons of liquid propane is at 50 F in a sealed tank. The tank develops a significant leak and propane escapes and vaporizes in a short period of time. To solve this problem you must use the propane tables not the common liquid properties.

What is the temperature near the hole in the propane tank due to the escaping propane in Fahrenheit to three significant digits? .   Include a minus sign if appropriate.

How many Btus of energy are needed to vaporize the entire 75 gallons of liquid propane? . Give your answer to three significant digits in Btus.

Do some internet research on the properties of composite materials. a) Compare the tensile strength of a typical glass fibre reinforced polymer with the tensile strength of a carbon fibre reinforced polymer. Make sure you the fibre lay-up is the same in your two examples and that you record what that is in your answer. Use data tables from reputable engineering or scientific web pages or material suppliers only and cite your reference(s).

Answer:....................................................................................................................... ................................................................................................................................. ................................................................................................................................. ................................................................................................................................. b) Write a few lines about metal-matrix composites and how their properties compare with polymer based composites.

Answer:....................................................................................................................... ................................................................................................................................. ................................................................................................................................. .................................................................................................................................

Air at 20°C (1 atm) is flowing over a 0.025-m diameter sphere with a velocity of 3.5 m/s. If the surface temperature of the sphere is constant at 80°C, determine the Reynolds number corresponding to the sphere, its average drag co-efficient, and the heat transfer rate from the sphere. The properties of air (1 atm) at the free stream temperature T_∞ = 20°C, ρ = 1.204 kg/m³, k = 0.02514 W/m∙K, μ = 1.825 × 10⁻⁵ kg/m∙s, and Pr = 0.7309. At the surface temperature T_s= 80°C: μ_s = 2.096 × 10⁻⁵ kg/m∙s. At the film temperature T_f = (80°C + 20°C)/2 = 50°C: ρ = 1.092 kg/m³ and v = 1.798 × 10⁻⁵ m²/s. (Round the Reynolds number to the nearest whole number and other answers to two decimal places.)

Look up today’s wholesale prices of natural gas in Texas (4.74 Dollars per thousand cubic feet) Calculate how much a kWh of electricity should cost, if it is being produced from (a) natural gas and (b) wind. You will need to worry about efficiency of combustion, energy content of natural gas, conversion of joules in kWh, etc. You will also need to figure out how to price wind, which of course blows for free.