  The problem of both electron and phonon scattering by wedge disclination
dipoles (WDD) is studied in the framework of the deformation potential
approach. The exact analytical results for the mean free path are obtained
within the Born approximation. The WDD-induced contribution to the residual
resistivity in nanocrystalline metals is estimated. Using the WDD-based model
of a grain boundary, the thermal conductivity, kappa, of polycrystals and
amorphous dielectrics is studied. It is shown that the low-temperature
crossover of kappa experimentally observed in LiF, NaCl, and sapphire can be
explained by the grain-boundary phonon scattering. A combination of two
scattering processes, the phonon scattering due to biaxial WDD and the
Rayleigh-type scattering, is suggested to be of importance in amorphous
dielectrics. Our results are in a good agreement with the experimentally
observed kappa in a-SiO_2, a-GeO_2 a-Se, and polystyrene over a wide
temperature range.
