Saturday, September 05, 2009

Paper delivery

Eli has come across a blog, AGW Observer, which has links to abstracts and Adobe Acrobat files of a number of useful papers on climate change related subjects. Have a peek. It looks like keeping the URL on your bookmark list might be useful


Jerrald Hayes said...

Thanks Eli. That's great. I've added AGW Observer to my list: References for Debating Science Deniers.
- Jerrald Hayes

Marion Delgado said...

Let me make a plug for Zotero, too, Eli. It's the bibliography plugin for firefox. goes well with sites like that.

David B. Benson said...

This is off-topic, but chemists lurk here.

I have some carbon and some hydrogen (thought experiment only). I want the reaction
C + 2H2 --> CH4
which I suppose is exothermic, but does this require some catylist, some strting heat or other special circumstance?

Dano said...

I swear I've seen this site before, and have it bookmarked, but not on the radar.

And a second to Marion's Zotero. I use it a lot. Scrapbook, not so much.



EliRabett said...

David, a good way to think about this is that to make CH4 from C and H2, you have to first break two hydrogen bonds and that costs a lot of energy. You either need a lot of heat and/or pressure or an electrical discharge or a catalyst and slightly less of the above. The role of all of these is to break the hydrogen bonds. That requires a lot of energy

H2 --> H + H is very endothermic without a catalyst. The heat of reaction is 436 kJ/mol.

The overall heat of reaction is easy to find since the heats of formation of C and H2 (assuming C is graphite, which is close enough) is zero and that of methane is -74.8 kJ/mole so on net you get 74.8 KJ out of the system, it is exothermic.

C + 2 H2 --> CH4

TheChemistryOfBeer said...

About C + 2H2 -> CH4, what Eli said, keeping in mind that at higher temperatures entropy is going to kill you. deltaG is zero at 935K. Maybe the Born-Haber design would be an appropriate start.

TP Hamilton

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Arthur said...

Eli, great site, thanks - the "hot spot" list actually had a few I hadn't looked at yet that might be very useful if I ever write up what I was working on on that...

On a probably completely unrelated note, I've been looking at the issue of modeling heat absorption by the surface diffusively as an improvement over the single-time-constant (fixed heat capacity) approximation. I'm sure climate models must do something along these lines, and it's got to be a standard solved problem, but I'm having trouble tracking down an analytical solution (if there is one).

Basically the problem is the semi-infinite one-dimensional heat equation with source at x=0 (the surface), but that boundary condition depends on a relationship between dT/dx and T at x = 0 (I think this qualifies as mixed boundary conditions - not Dirichlet or Neumann anyway). I'm feeling pretty rust on this one, if anybody has more of a clue I'd appreciate it, thanks!

EliRabett said...

A note to all bog whores. Eli will delete all non clever attempts and leave your name there as a sign of shame.

Be creative

David B. Benson said...

EliRabett & Tracy P. Hamilton --- I think I have it now. Thak you!