We use and support open-source software:
this server runs on open source
since release 0.8 the LIBPF UI (User Interface) module has been open-sourced, following the transition to the Qt cross-platform application framework
from the start the simevo process app is open source.
On the other hand the core of LIBPF, the library itself, is not open source: the decision to keep it proprietary is the result of evaluating the characteristics of the user community and of the destination markets.
The open source business model is very successful at re-implementing general purpose commercial software (example: LibreOffice vs. Microsoft Office, Linux vs. UNIX) or at writing new small, special purpose tools in areas where there is great enthusiasm from the community (example: peer-to-peer or multimedia).
There is a number of open-source numeric software libraries and a number of open-source scientific tools but they all were either funded by research grants or developed by people working full-time in state-owned agencies.
There is few complex scientific or engineering open source tools or libraries available as open-source software.
Process simulation software in particular is complex and requires highly skilled programmers and process engineers. But the worldwide community of chemical engineers is comparatively small, and among them the number of "hackers" is an even smaller subset; this limits the number of volunteers that could enroll in an open source initiative.
An additional problem is related with confidentiality issues; for companies who invest in patents to protect their process know-how it is unthinkable to give back code to the community.
For all these reasons LIBPF is proprietary - but our business model is open !