A system includes, in one example, a shroud configured to circumscribe a plurality of rotor blades of a gas rotor engine, and at least one rub button including a head portion having a height configured to extend into a flow path region of the shroud along a central axis of the rub button that extends radially into the flow path region. The composite sheet material can further include a substantially fluid impervious layer. In an aspect, a method for quality monitoring in a medical system, in particular a medical therapy system or particle therapy system is described, in which such a phantom is coupled via a fixation device to a positioning device and, with the aid of the positioning device, is brought to a predefined position. A source of electrical signals provides the power to heat the material intermediate the pair of jaws. The IWF receives the message, converts the message according to the decided messaging service, and transmits the converted message to the recipient.