Hi,

I am just trying to assist here.

"toughest material ....600J/g"
......
"at 600J/g tensile strength"


Are incompatible.

Toughness and tensile strength are not the same thing AT ALL.

IIRC toughness is the Energy required to break a test specimen.
The energy is delivered in a short time (e.g. with a hammer blow).

The units will be I guess Energy per unit Area.

Tensile strength is the force per unit area required to (slowly)
break the material in tension.

So not only are the two not directly related, it looks to me as if the
wikipedia article is misleading.


http://en.wikipedia.org/wiki/Nanotube
Says:
"was tested to have a tensile strength of 63GPa"
I say: - This is a unit of Pressure (force per unit area )
which I agree with.

http://en.wikipedia.org/wiki/Nanotube
Says:
"In comparison, the bullet-resistant fiber Kevlar is 27-33J/g"

Maybe there is some sense to the idea of toughness
having the units 27-33J/g however I can't see it at present.