Residual properties of non-positively curved groups

I am a researcher in geometric group theory. Actions of groups on geometric objects tell us about properties of the groups. In my PhD project, I attempt to translate properties of free groups and other
hyperbolic groups into the context of non-positively curved groups. Specifically, I would like to explore residual properties such as residual finiteness and subgroup separability.

Examples of such problems are:
- determine conditions of residual finiteness for a multiple HNN extension of a free group
- examine typical finite completion of a pre-cover of a right-angled Artin group.

Special cube complexes are particularly useful in this area.