Which design of the walls would be most desirable help avoid echoes? A
They should use bumpy walls for all four sides.
B
They should use bumpy walls for only one side.
С
They should use smooth walls for all four sides.
D
They should use smooth walls for only one side.

Which of the following represents an upright image? a. -do b. +m c. -m d. +do

The consumption of fossil fuels could be

Carbon is allowed to diffuse through a steel plate 15 mm thick. the concentrations of carbon at the two faces are 0.65 and 0.30 kg c/m^3 fe, which are maintained constant. if the preexponential and activation energy are 6.2 x 10-7 m2 /s and 80,000 j/mol, respectively, compute the temperature at which the diffusion flux is 1.43 x 10^-9 kg/m^2 -s.