1.
(a) Calculate the heat flux through a sheet of brass 7.5 mm (0.30 in.) thick if the temperatures at the two faces are 150 and 50°C (302 and 122°F); assume steady-state heat flow.
(b) What is the heat loss per hour if the area of the sheet is 0.5 m2 (5.4 ft2)?
(c) What will be the heat loss per hour if soda-lime glass instead of brass is used?
(d)Calculate the heat loss per hour if brass is used and the thickness is increased to 15 mm (0.59 in.).
2.
(a) Would you expect Equation 19.7 to be valid for ceramic and polymeric materials? Why or why not?
(b) Estimate the value for the Wiedemann-Franz constantL [in D-W/(K)2] at room temperature (293 K) for the following nonmetals: zirconia (3 mol% Y2O3), diamond (synthetic), gallium ar- senide (intrinsic), poly(ethylene terephthal- ate) (PET), and silicone. Consult Tables B.7 and B.9 in Appendix B.