Any word on whether there was a decline in this type of tumor when CMOS x-ray imaging started being used in dentistry? Using CMOS rather than film supposedly requires less exposure time or less x-ray intensity in order to obtain an image comparable to film. I see the article does comment on the decreased intensity of x-ray source now as compared to a decade or so ago, but unless they couldn't readily identify this type of tumor back then, then I would expect to have seen a decline in this type of tumor as well.

What I saw from the proposal is that they will use the excess heat from the Zn and O2 gasses to at least assist in this (not sure if there is enough energy in 1 mole of Zn and 0.5 moles of O2 at 1750C to raise all the reactants in the 2nd process to 420C). I would also like to compare the energy lost in waste heat to that of the energy lost in the electrolysis of water. I think that there have been ideas for using solar heating at much lower temperatures where it is used to just boil water and power a turbine (presumably using a liquid that is better at absorbing solar radiation than water and then transferring the energy to the water). The electricity could then be used to split water when it is not being used to power something else. Again, that's if the energy loss is less. Something I would have assumed they looked into.

Also, sorry for the earlier comments. As a grad student I regularly did these reactions at (relatively) moderate temperatures in order to obtain ZnO crystals. I did not think to look what the products of Zn+H2O at lower temperatures produced.

I don't think this is true. Water doesn't start to decompose until roughly 2000C. So, having something that decomposes at a lower temperature as well as a material that stays put longer (ZnO stays a solid until it decomposes) is quite a bit better.

Here is a proposal posted on the National Renewable Energy Lab's website ( http://www.nrel.gov/hydrogen/pdfs/development_solar-thermal_zno.pdf ). It discusses in further detail the process by which ZnO is decomposed into Zn metal and oxygen, using the Zn metal to react with water to form ZnO and H2 gas.

Here is an article from work being done at NREL ( http://www.nrel.gov/hydrogen/pdfs/development_solar-thermal_zno.pdf ). Condensing Zn vapor from the ZnO decomposition can be done by rapidly cooling. They seem to claim that the reaction of liquid Zn metal with water gas favors the production of ZnO, not zinc hydroxide.

Also, to call ZnO primarily ionic is neglecting that it is very close to 50/50 ionic/covalently bonded. Last, I was not aware that some classified metal-oxides as salts.

The article clearly states that it is Zn vapor reacted with water. Pardon me for starting from where the linked article left off. ...and yes, I did state "still hot, but cool it just below the decomposition temperature of ZnO".

Yes, I see where the confusion is. This is at high temperatures where Zn and H2O will form ZnO and H2. This not done at the temperatures where zinc hydroxide will form.

Okay, perhaps I should clarify here as well... this is being done at very high temperatures. This will form ZnO at those temperatures, not zinc hydroxide.

I'm not sure where you get Zn(OH)2. Zn vapor and water do not form zinc hydroxide. Also, ZnO is not a salt. It will not dissociate to form zinc ions when placed in water.