Which of the following statements about coral reef preservation efforts is true?
a.
in order to preserve coral reefs, all aquarium trade in coral reef organisms must end.
b.
legislation has had no impact on coral reef preservation efforts.
c.
various preservation methods have had some positive impact on coral reef preservation.
d.
education of fishermen has eliminated all coral reef loss.

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.