Create an evidence item and use check_out and check_in to add names to the custody chain. use the display_custody_chain function to output the names. create a case and use add_evidence to add evidence items to the case. use the display inventory function on the case to see the evidence.

Awall of 0.5m thickness is to be constructed from a material which has average thermal conductivity of 1.4 w/mk. the wall is to be insulated with a material having an average thermal conductivity of 0.35 w/mk so that heat loss per square meter shall not exceed 1450 w. assume inner wall surface temperature of 1200°c and outer surface temperature of the insulation to be 15°c. calculate the thickness of insulation required.