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Crushed wood is stronger than steel

nature.com

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Re: Crushed wood is stronger than steel

#51

Post by anvandare »

jahnu wrote: post #17
gonvaled wrote: post #12

Earlier quoted context omitted.

Mini black hole, evaporating fast unless you feed it faster!

Are there any interesting trivia figures for that? Like how long would it take to evaporate a black hole with an event horizon the size of a basketball, golf ball, grain of sand, whatever?

You can play around with it here: http://xaonon.dyndns.org/hawking/

* basketball (radius ~ 12cm): 1.4e54 years

* golf ball (radius ~ 2cm): 6.5e51 years

* grain of sand (radius ~ 1mm): 8.1e47 years

So all of them "so ludicrously long that these are just numbers". To put it in human terms:

* a black hole with a mass of 70 kilograms will evaporate in 0.028 nanoseconds

* a black hole that will evaporate in 80 years has a mass of ~ 311,000 tons, and would be... Impossibly small (2000 times smaller than a proton charge radius).

And that's why most of the time of the universe (from 10^40 years, long after the last stars have died, until 10^100 years) will be just black holes vaporizing, after which (10^100 to 10^2500) years it'll be just a few stray protons, photons, and electrons floating around (assuming they don't disintegrate either).

https://en.wikipedia.org/wiki/Future_of_an_expanding_univers...

Re: Crushed wood is stronger than steel

#54

Post by thecatspaw »

pbhjpbhj wrote: post #48
Filligree wrote: post #21

Earlier quoted context omitted.

It's still wood, and wood is only barely biodegradable. If you take decent care of it it'll last for centuries.

A fallen tree in damp conditions rots down in a year or so. Seems pretty biodegradable. Your second sentence I have no problem with.

a fallen tree will also easily get overrun by bugs and animals and does not have a closed surface, making it prone to rot

Re: Crushed wood is stronger than steel

#55

Post by bpyne »

jacquesm wrote: post #6

The most expensive wooden floors have the end grain exposed facing upwards and this is then compressed down, much like the top of a good quality butchers block. Those floors are just about indestructible. The heavier such floors are used the stronger they get! The wood in the article is compressed crosswise to the grain (so they get thinner rather than shorter), using the original planks as the raw organic material t…

Sorry to go on a tangent, but your comment reminded me of a book I read about the Chinese culinary culture pre-revolution. Chinese chefs had, and may still have, wooden cutting boards that were conditioned somehow such that they were as hard as stone. (There was also an implication that they resisted bacteria unlike normal wood boards when not scoured properly.) These boards were passed down from generation to generation.

The bit about the cutting boards being as hard as stone, is that pure hyperbole or is it possible?

Re: Crushed wood is stronger than steel

#57

Post by cdsboy »

bpyne wrote: post #55
jacquesm wrote: post #6

The most expensive wooden floors have the end grain exposed facing upwards and this is then compressed down, much like the top of a good quality butchers block. Those floors are just about indestructible. The heavier such floors are used the stronger they get! The wood in the article is compressed crosswise to the grain (so they get thinner rather than shorter), using the original planks as the raw organic material t…

Sorry to go on a tangent, but your comment reminded me of a book I read about the Chinese culinary culture pre-revolution. Chinese chefs had, and may still have, wooden cutting boards that were conditioned somehow such that they were as hard as stone. (There was also an implication that they resisted bacteria unlike normal wood boards when not scoured properly.) These boards were passed down from generation to genera…

Doesn't having a cutting board as hard as stone defeat the purpose of having a cutting board?

Re: Crushed wood is stronger than steel

#58

Post by pwks »

lr4444lr wrote: post #9

Interesting, but what about biodegradability? Will it not be eroded by microorganisms in the outdoors over time? It is still wood, after all.

It depends on the amount of water in the wood. If it is lower than 18% or so (we usually dry wood to this percentage when we use it as a building material) then neither insects or fungus will attack it and it won't rot.

Re: Crushed wood is stronger than steel

#59

Post by tclancy »

willvarfar wrote: post #19

People may also find Pykrete interesting https://en.wikipedia.org/wiki/Pykrete Its adding wood pulp to ice to make the ice much much tougher. It was invented by the epitome boffin Geoffrey Pyke, who proposed they build an aircraft carrier of it! https://en.wikipedia.org/wiki/Project_Habakkuk

There was a short piece on 99% Invisible about this recently: https://99percentinvisible.org/episode/mini-stories-volume-3... (worth a listen just for the part about the plaque they erected (?) where the ship now sits).

Re: Crushed wood is stronger than steel

#60

Post by mr_overalls »

pbhjpbhj wrote: post #48
Filligree wrote: post #21

Earlier quoted context omitted.

It's still wood, and wood is only barely biodegradable. If you take decent care of it it'll last for centuries.

A fallen tree in damp conditions rots down in a year or so. Seems pretty biodegradable. Your second sentence I have no problem with.

Yeah, "decent care" means "kept away from moisture, fire, and bugs."

Such care can be difficult in the long term, but yields results like the beautiful 700 year-old woodwork in this English cathedral. (And of course the comments mention the Buddhist temple Hōryū-ji.)

http://blog.longnow.org/02009/01/12/how-long-can-wood-last/

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