  To understand the role of electron correlation and disorder on persistent
currents in isolated 1D rings threaded by magnetic flux $\phi$, we study the
behavior of persistent currents in aperiodic and ordered binary alloy rings.
These systems may be regarded as disordered systems with well-defined
long-range order so that we do not have to perform any configuration averaging
of the physical quantities. We see that in the absence of interaction, disorder
suppresses persistent currents by orders of magnitude and also removes its
discontinuity as a function of $\phi$. As we introduce electron correlation, we
get enhancement of the currents in certain disordered rings. Quite
interestingly we observe that in some cases, electron correlation produces
kink-like structures in the persistent current as a function of $\phi$. This
may be considered as anomalous Aharonov-Bohm oscillations of the persistent
current and recent experimental observations support such oscillations. We find
that the persistent current converges with the size of the rings.
