  Significant nucleosynthesis is possible in the centrifugal pressure-supported
dense and hot region of the accretion flows which deviate from Keplerian disks
around black holes. We compute composition changes and energy generations due
to such nuclear processes. We use a network containing 255 species and follow
the changes in composition. Highly viscous, high-accretion-rate flows deviate
from a Keplerian disk very close to the black hole and the temperature of the
flow is very small due to Compton cooling. No significant nucleosynthesis takes
place in these cases. Low-viscosity and lower-accretion-rate hot flows deviate
farther out and significant changes in composition are possible in these cases.
We suggest that such changes in composition could be contributing to the
metallicities of the galaxies. Moreover, the radial variation of the energy
generation/absorption specifically due to proton capture and photo-dissociation
reactions could cause instabilities in the inner regions of the accretion
flows. For most of these cases sonic point oscillations may take place. We
discuss the possibility of neutrino emissions.
