An object is to provide an exhaust-gas control device for a gas engine whereby NOx is reduced and fuel consumption is improved by performing NOx restriction operation when an environmental or geographical condition in which the amount of NOx emission needs to be temporarily restricted is satisfied, and otherwise performing stable operation focusing on the fuel consumption. The method includes associating an identification tag or ABS ECU that is configured to broadcast a trailer identification signal with a trailer. Thermal desorption gas analysis is performed on at least a portion of the magnetostrictive film undergoing the heat treatment step. The evaporator further includes a main feed water line in fluid communication with the most upstream group. Logic paths in the ring of non-scan latches are exercised. The method includes removing viscera from a carcass, accumulating the carcass along a dead rail stack of the meat processing line, washing the carcass, and inspecting the carcass at an inspection station following the act of washing the carcass.