Do you know about any engineering applications authored by using Mendix?
In general, where can I find Mendix applications? I found some on the Mendix App Store but I guess not all the application are published in this way.
Yes, I know of several. I am not sure exactly what you’re asking, do you want to see examples of such applications? Most applications are built for clients that use them in their own organizations, so they are not publicly available.
You could check out https://gallery.mendix.com/ to see some demo applications, or contact Mx Sales to see if they have more demo material.