Chainsaw
Chainsaw is an OWLReasoner implementation aimed at large ontologies
Development for Chainsaw is at https://bitbucket.org/ignazio1977/chainsaw
For recent source code and support, please visit the BitBucket page.
Chainsaw uses modularisation and atomic decomposition to delegate reasoning tasks to other OWL 2 reasoners; it leverages Divide and Conquer to reduce the ontology to the part necessary to answer a specific query.