A host device comprises a controller and a connector. In one embodiment, a system includes a thermal heat source configured to be either removably coupled to or positioned proximate to the composite material to generate a localized thermal field in a selected area of the composite material. A dynamic switching subsystem is coupled to the local digital switch via a first communication link and coupled to the remote terminals using one or more second communication links. Other embodiments of the present invention provide methods andor apparatus suitable for rotational control andor plunge depth control for FSW of titanium alloys andor other high temperature alloys such as super alloys. The diffusion structure may have a first layer adjacent the respective fluid flow field plate and a second layer, the first layer having a relatively higher permeability than the second layer, the second layer being a support layer having a stiffness greater than that of the first layer. The other end of the sleeve includes an adjusting ring, which has two inwardly directed half-ringed, oblique limiting members, which are hit by fin of the piston during puncturing of skin.