5. Anyone who has ever owned a car will recognize the following situations. Suggest what might be occurring in the structure of the material in each case. a. The insides of the windows develop a haze that resembles smoke, but it is not smoke. b. Vinyl seats crack after a period of time. Those areas exposed to sunlight are especially susceptible.

7 Draw a log modulus-temperature plot for a typical amorphous polymer. Indicate the
regions exhibited by the polymer (eg., glass, rubbery, viscous, leathery)?
a. To which regions do the following polymers belong at room temperature: chewing
gum, a hydrogel used as a styling gel; PVC notebook covers; rubber bands,
PlexiglassTM ?
b. Draw another similar graph and sketch comparative curves for the following
polymers: i. Amorphous ii. Crystalline iii. Crosslinked iv. High molecular weight
v. Low molecular weight

Through a double tube exchanger hot water circulates through the inner tube and water
fry through the outer tube. For countercurrent arrangement the following data is displayed:
Cold water inlet temperature Tca 24.5 ° C
Cold water outlet temperature Tcb 48.0 ° C
Hot water inlet temperature Tha 86 ° C
Hot water outlet temperature Thb 55 ° C
Cold water flow 2.00 gal / min
Calliente water flow 2.00 gal / min
Transfer area 0.65 m2 Length of the two pipes is the same 186 cm
to. Build the temperature vs. length diagram
b. Calculate the ΔT1 and ΔT2 approaches c. The temperature ranges ΔTc and ΔTh
d. The average log temperature
and. The global coefficient of heat transfer

Calculate the heat flux (W / m2) through a composite wall made of material A
whose k = 40 W / m-K and has a thickness of 30 cm, a material B whose k = 0.05 W / m-K and a
thickness of 3 cm; and a material C whose k = 0.004 W / m-K, its thickness is 0.5 cm.

Assuming normal heptane and normal octane to form ideal solutions, do the following:

d) Calculate the dew pressure of the solution at 40 ◦C.

e) Calculate the bubble temperature at 1 bar.

f) Calculate the dew temperature at 1 bar.

g) Calculate the amount and composition of vapor and liquid when a solution with z1 = 0.45 is flashed to 40 ◦C, 0.065 bar. The saturation pressures of the two components are given by the Antoine equation:

ln Pi sat = Ai − Bi/(Ci + T)

where P sat is in mm-Hg, t is in Kelvin, and the parameters

Ai , Bi , Ci , are

nC8: A = 15.9426 B = 3120.29 C = –63.63

nC7: A = 15.8737 B = 2911.32 C= –56.51

Prove for an adiabatic TP ^ 1-gamma / gamma = constant process. Use the first law of thermodynamics.

A pub opens its door for business at 6:00 PM. From 6:00 P.M. to 8:00 P.M. 50 smokers in the pub smoke 2 cigarettes per hour and each cigarette emits 4mg formaldehyde. Fresh air is introduced into the pub @ 1,000 m3/hr. At 8:00 P.M. the number of smokers in the pub increases from 50 to 75 and as a result, the fresh air flow rate is increased from 1,000 m3/hr to 1,500 m3/hr to flush out the stale air. Assume that all smokers in the pub still smoke 2 cigarettes per hour, what is the formaldehyde concentration (ppmv) in the air inside the pub @ 9:00 P.M.?

Derive the Kremser equation analytically to solve dilute-gas absorption based design problems. Kremser equation is defined in Wankat Equation 12-22 (pp. 466; section 12.4 of 3rd edition textbook). Remember to define all variables/parameters used and clearly state all assumptions.

Ironmaking and steelmaking face challenges of reducing energy consumption and environment pollution. What is your proposal to make ironmaking and steelmaking more sustainable?

Pressure in a storage tank is maintained at 1 MN/m² to supply water at 20^oC and atmospheric pressure through 200 m (equivalent length, including fittings) of drawn steel tubing (30 mm OD, 6 mm wall thickness). What flow rate of water can be maintained?

Calculate the dew point temperature (to the nearest ºC); the corresponding vapor pressures of ethanol and methanol (units of mm Hg); and the equilibrium liquid molar compositions associated with a saturated vapor mixture containing 30% by mole ethanol and the balance methanol. Pressure of the system is 1 atm(abs).

Assume 400 ft3/min (measured at STP) of a gas mixture (Stream F) at 150 °F and 1.70 atm is fed to a reactor. The mixture consists of 65 mol% methane and 35 mol% ethane. Air (Stream A) at 75 °F and 1.20 atm is fed to the reactor in 20% excess. Aside from the excess air, the flue gas from the reactor contains only CO2 and H2O(vapor), and comes out at 1300 °F and 1.0 atm. Assume all pressures are observed by reading a pressure gauge. Keep the units used in your solution consistent with those in the problem statement.

a). Draw a labeled flowchart. Be sure to show units for all rates and compositions. Use the names (F, A, etc.) given in the description.

b). Calculate the molar flow rate (lbmol/min) of the gas mixture (Stream F) fed to the reactor.

c). Solve for the required volumetric flow rate of the air stream. Express your answer as ft3/min of air at STP conditions.

d). Calculate the volumetric flow rate of the furnace stack gas in units of ft3/min.

A particular power plant operates with a heat-source reservoir at 350°C and a heat-sink reservoir at 30°C. It has a thermal efficiency equal to 67% of the Carnot-engine thermal efficiency for the same temperatures.

What is the thermal efficiency of the plant?

The thermal efficiency of the plant is  .

A steady-flow adiabatic turbine (expander) accepts gas at conditions T₁, P₁ and discharges at conditions T₂, P₂. Assuming ideal gases, determine (per mole of gas) W, W_ideal, W_lost, and S_G for the following case. Take T_σ = 300 K and R = 8.314 J·mol⁻¹·K⁻¹.

T₁ = 530 K, P₁ = 8 bar, T₂ = 424 K, P₂ = 1.6 bar, and C_P/R = 7/2.

The following data were obtained for the adsorption of n-butane on a porous solid (catalyst).  

Calculate the area (in m²) occupied by a n-butane molecule at 150°C.