Because they have to be approved by a moderator. We've had people attach porn in the past, so every attachment goes through a moderation queue. I've just approved all your attachments.
Wab=-3315.4J Wca=nRTLn(Va/Vc)=-2108.98
Are you sure about that? ab is an expansion, while ca is a compression. [itex]\int p dV[/itex] has a different sign along each path.