Enthalpy of process

Description
In this lecture we deal with are not constant volume processes. So energy, which has this wonderful property here, du is Cv dt for constant volume process, which happens to be equal to d q, constant volume, because there's no change. there's no work if you've got a constant volume process. So du here is a very interesting quantity, because it's related to the heat that's going in or out of the system under constant volume process. But as I said, we're not operating usually in a constant volume environment. When I flail my arms around I generate work and heat. This is not a constant volume process. In this lecture we talk about Joule-Thomson expansion, which is an irreversible expansion through a nozzle, through a porous plug, constant enthalpy expansion.Prof. Keith A. Nelson and Prof. Moungi Bawendi, 5.60 Thermodynamics & Kinetics, Spring 2008, Massachusetts Institute of Technology: MIT OpenCourseWare), http://ocw.mit.edu (Accessed 2 january 2011). License: Creative Commons BY-NC-SA: http://ocw.mit.edu/terms/#cc