  Recent measurements on a class of high-Tc superconductors (HTSCs) have shown
that Cooper-pairs wavefunction is a d-wave, while in another class, d-wave and
s-wave may coexist. Conventional low-Tc superconductors are s-wave
superconductors. When d-wave Cooper-pairs are injected in a superconductor that
can sustain s-wave pairing, d-wave pairs are subject to transition 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 that show a gravitational interaction between inhomogeneous 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.
