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Dissipative systems and boundaries
The conservation of energy requries that in a closed system (where there is no energy crossing the boundary, either in or out) the total amount remains exactly constant, so adding up all the energies, potential, kinetic, heat gives a constant, measured in joules. Most systems are not closed, and it's a matter of choice where we draw a system boundary. I think it's important to be clear about the thermodynamic manifestation of energy - the generation of heat is not, of course, loss, it is just a movement of the system towards a more entropic state. The heat and noise created by waves may transfer energy to the atmosphere and coastal matter, but in the overall system there is no energy loss. Looking at the sea as a system means there is energy leaving it, but at the same time the sun and wind add energy to it, so it's a dynamic system with flux in and out. Overall I'd say there is conservation in a closed system, but closed systems can consist of many interacting dissipative systems, all exchanging energy. I'm sure someone could express this ina neater form, it's early in the day for me.
Jas 11:50, 12 January 2007 (UTC)
Biblical Usage of Dissipation
Ephesians 5:18 provides; And do not get drunk with wine, for that is dissipation, but be filled with the Spirit, [5:19] speaking to one another in psalms and hymns and spiritual songs, singing and making melody with your heart to the lord;...
Dissipation used in this biblical context appears to define the term as a concept of a weakening or divided spirituality. —Preceding unsigned comment added by Jentingh1 (talk • contribs) 12:02, 7 April 2009 (UTC)
In many numerical simulations, forms of artificial dissipation are intentionally added in order to make a system numerically stable. For instance, Runge-Kutta 4 is not always stable when using multigrid methods and various modes can grow exponentially at grid boundaries. However, it's been found that intentionally adding small amounts of dissipation over the domain can overcome this problem without significantly affecting the physics being simulated. I don't know the citation but I am certain this is discussed in a book by Kreis and Oliger. —Preceding unsigned comment added by Grigjd3 (talk • contribs) 13:52, 30 September 2010 (UTC)
I was thinking the same thing. One possible citiation is Thomas, J.W. Numerical Partial Differential Equation: Finite Difference Methods. Springer-Verlag. (1995). I've made a cursory change to the main article.
deleted sub-section 'Energy'
I deleted the new sub-section headed 'Energy' because it had a notion of heat that contradicts present Wikipedia thermodynamic consensus. The deleted quote treated heat as a state variable. The present Wikipedia thermodynamic consensus is that heat is a process variable. The source was of a chatty character in a foreign language and was a unsuitable source for an article of this kind.Chjoaygame (talk) 13:00, 15 March 2014 (UTC)
- Please provide a source for your claim that the part you mentioned is contradicting the Wikipedia thermodynamic consensus. See for a proper description https://en.wikipedia.org/wiki/Thermodynamics which is very clear on energy and heat. The "deleted quote" treated heat part of a process function, which is considered 101 of Thermodynamics. Prokaryotes (talk) 14:05, 15 March 2014 (UTC)
deleted sub-section 'Physics'
I have deleted the new sub-section headed 'Physics" because it was not about physics. It was about computation. The deleted material may well have a place in an article about computation, but it would not be a good plan to try to extend the reach of the present article to cover dissipation in all its possible meanings. The present article is about dissipation as it is meant in physics, especially in thermodynamics.
True, considering that there are uses of the term 'dissipation' other than in physics, especially in thermodynamics, it would be a good idea to change the heading of the present article to 'Dissipation (thermodynamics)' or to 'Dissipation (physics)'. I am not familiar with the process for changing the heading or title of an article. I know it requires special expertise. If anyone here knows the proper process, I would be glad if they would set it in motion.Chjoaygame (talk) 13:11, 15 March 2014 (UTC)
deleted sub-section 'Mathematics'
I have deleted the new sub-section headed 'Mathematics'. While an advanced article on physical dissipation could perhaps use such material, it is not suitable for the present article, which is not advanced.Chjoaygame (talk) 13:15, 15 March 2014 (UTC)
- Hmm, that is because you changed the scope of the article (renaming and such). And this part wasn't new ( i just added a headline), it has been there in your earlier edits. Prokaryotes (talk) 13:52, 15 March 2014 (UTC)
when all else fails
When all else fails, connect the device with good leads, and turn the power switch to the 'on' position. On no account read the instructions. Well, I did read the instructions, and have moved the page to have a more precise title. It didn't need such great expertise after all!Chjoaygame (talk) 13:31, 15 March 2014 (UTC)