Technician A says that manually opening an exhaust gas recirculation (EGR) valve with a vacuum pump or scan tool will cause the engine to idle roughly or stall. Technician B says that blocking the EGR valve passages will have no effect on the OBD-II. Who is correct

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.