Assignment 7 - 19.14 (a) Calculate the heat flux through a...

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1 of 2 FACULTY OF ENGINEERING AND APPLIED SCIENCE ENGR 4250 - Advanced Materials Engineering Instructor: Dr. Ali Keshavarz TA: Maryam Talimi ASSIGNMENT # Due Date: Thursday March 31, 2011 at noon. Please submit your assignment with this cover page by noon to drop-box #3 located on ground floor OPG Building. Question 1 2 3 4 Total Mark NAME: ID: 7
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2 of 2 Solve the following problems 18.2 A copper wire 100 m long must experience a voltage drop of less than 1.5 V when a current of 2.5 A passes through it. Using the data in Table 18.1, compute the minimum diameter of the wire. 18.14 (a) Using the data in Figure 18.8, determine the values of ρ 0 and a from Equation 18.10 for pure copper. Take the temperature T to be in degrees Celsius. (b) Determine the value of A in Equation 18.11 for nickel as an impurity in copper, using the data in Figure 18.8. (c) Using the results of parts (a) and (b), estimate the electrical resistivity of copper containing 1.75 at% Ni at 100°C.
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Unformatted text preview: 19.14 (a) Calculate the heat flux through a sheet of steel 10 mm (0.39 in.) thick if the temperatures at the two faces are 300 and 100C (572 and 212F); assume steady-state heat flow. (b) What is the heat loss per hour if the area of the sheet is 0.25 m 2 (2.7 ft 2 )? (c) What will be the heat loss per hour if sodalime glass instead of steel is used? (d) Calculate the heat loss per hour if steel is used and the thickness is increased to 20 mm (0.79 in.). 19.15 (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 constant L [in -W/(K) 2 ] at room temperature (293 K) for the following nonmetals: silicon (intrinsic), glass-ceramic (Pyroceram), fused silica, polycarbonate, and polytetrafluoroethylene. Consult Tables B.7 and B.9 in Appendix B....
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Assignment 7 - 19.14 (a) Calculate the heat flux through a...

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