Devices and methods are presented in which heat transfer from the surface of a high-temperature exothermic reaction mass is removed while largely maintaining the temperature of the mass at a desired level by allowing heat to radiate from the surface of the reaction mass to a first absorber that forms part of a reactor vessel, from which the heat is then removed using a second absorber. The flexure includes an integral actuator for moving the mass member with respect to the frame. Described also is a device enabling protocol using authentication accumulation to secure against threats from a rogue device pretending to be another device in the network such as in man-in-the-middle and replay attacks. The at least one vibration reduction unit encloses the shaft-coupling portion. The helmet liner is then fitted in the helmet shell to form a helmet.