A metal x-ray device component is provided that includes a high emissivity inorganically bonded ceramic coating that can be applied with minimal surface preparation and that provides good resistance to corrosion and oxidation of substrates in high temperature, vacuum environments. One aspect of the invention involves a computer data structure that includes an email message with an embedded link. A microprocessor processes signals from the pressure sensor to determine speed corresponding to the change in elevation. The dense packing of molecular chains in the fluoroalkyl shell combined with a mesoporous structure imparts a very low surface energy, a very high specific surface area, and surface texture over a wide range of length scales. The manifold assembly directs fluid to the single package rather than scattering fluid outputs to multiple sensor locations, simplifying the overall assembly configuration. The hardenable dental composite includes at least two adjacent regions with different concentrations of a photoinitiator, at least two adjacent regions with different photoinitiators, or both.