  Recent measurements on a class of high-Tc superconductors (HTSC) have shown
that Cooper-pairs binding may be associated to a d-wave, while in another
class, d and s waves may coexist. When d-wave Cooper-pairs are injected in a
superconductor that can sustain s-wave binding, d-wave pairs decay to s-wave
pairs and energy is irradiated by means of gravitons. We show that in s-wave to
d-wave type superconductor (SDS) junctions in an equilibrium condition no net
gravitational wave energy is emitted, on the other hand under non equilibrium
conditions a net gravitational wave energy is emitted by the junction.
Experiments which show a gravitational interaction between inomogeneus high-Tc
superconductors, under non equilibrium conditions, and test objects may be
understood by accepting a possibility of emission of gravitational radiation
from SDS junctions.
