New Scientist's Take on the "Slacktivism" Trend

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The discussion centers on the potential of magnesium, cesium, and rubidium as recyclable energy carriers, comparing them to iron, aluminum, and boron. Participants express skepticism about the feasibility of using cesium and rubidium due to their high costs and reactivity with oxygen. Key points include the oxidation process of metals, which increases mass and volume, and the need to evaluate the specific energy of these metals compared to existing alternatives. Questions arise about the conversion of thermal energy to mechanical energy for propulsion, the disposal of metal oxides, and the energy required to revert oxides back to metals. The conversation also touches on the existing use of aluminum in solid fuel rocket propulsion, suggesting a need for a comprehensive analysis of the entire process to determine viability. Concerns about the safe storage of highly reactive metals like cesium and rubidium are noted, indicating that innovative solutions would be necessary for practical applications.
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Not being a chemist, well, having a degree in it anyway, myself I don't know if magnesium, cesium and rubidium could be used as a recyclable energy carrier like the iron, aluminum and boron mentioned in the article. These three elements are quite reactive with oxygen, surely they could be used?
Aircraft or military machines is the applications for such fuel, that I can think of anyway. For most fueling applications cesium and rubidium would cost far too much wouldn't they?
 
One would have to look at the total process - to see if that is feasible.

It appears the idea is to oxidize the metal, which means change in volume and mass - with mass increasing. What is the specific energy of the system, as compared to alternatives?

Also, how is the thermal energy converted to mechanical energy for propulsion?

And where does one deposit the metal oxide?

And how much energy is consumed in reconverting oxide to metal?

Oxidation of Al is part of solid fuel rocket propulsion technology already - e.g. Shuttle SRBs.
 
Astronuc said:
One would have to look at the total process - to see if that is feasible.
It appears the idea is to oxidize the metal, which means change in volume and mass - with mass increasing. What is the specific energy of the system, as compared to alternatives?
Also, how is the thermal energy converted to mechanical energy for propulsion?
And where does one deposit the metal oxide?
And how much energy is consumed in reconverting oxide to metal?
Oxidation of Al is part of solid fuel rocket propulsion technology already - e.g. Shuttle SRBs.

Ok, I've got nothing though.

Don't know, article doesn't say much.

Like in a normal internal combustion engine.

Don't know, some sort of tank in the car I guess.

It'd depend what metal it is, aluminum would take more than iron. Boron would take more than both of them, by several times.

Yes, but you can't run cars that way.

Magnesium, cesium and rubidium are hugely reactive. Small vials of the latter two reacting with water are like bombs going off. They'd make very, very high density fuel, wouldn't they? Sure, a way to keep the latter two from just oxidising in the air would have to be thought up, something invloving storage in a vacuum tank, or Noble gas, probably.
 
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