Methods and apparatus for use by a mobile communication device in switching operation for communications from a wireless wide area network to a wireless local area network are disclosed. The method includes: obtaining a cold zone temperature from a cold zone collection point, where the cold zone collection point is arranged in a position, away from a heat emitting element, of the hand-held electronic device; and selecting an overheat protection scheme that corresponds to the cold zone temperature and a hot zone temperature. The said resistance or partitions function to reduce or prevent the flow communication between any two groups of fuel assemblies through the common plena, thus preventing the excitation of the neutron flux first azimuthal harmonic mode. The movable mirror and fixed mirror reflect the optical energy to a receiver, and a change in the Fabry-Perot microcavity’s reflectivity is interferometrically determined.