It would be appreciated if they used actual units and photos of the "super wood."
"Stronger than (some low ball grade of) steel" is not a unit as it's super easy to sandbag the thing you're comparing to and mislead people about how important the development is.
Are units like MPa or psi not commonly understood by the science-curious public? Why would someone like Scientific American not use actual units? This stuff is taught to basically everyone in high school.
(Maybe this is just the graduate student instructor in me, but it bothers me to no end that regular units are not used...)
EDIT: The paper does, of course use proper units (annoyingly, not in the abstract...).
The densified "super wood" gets a specific strength (strength per unit density) of:
422.2 ± 36.3 MPa/(grams/cm^3).
It is an impressive figure.
State of the art carbon fiber is ~3900 MPa/(g/cm^3), though, and lots of other fibers are higher than this "super wood" (including the best grades of Balsa, I believe).
Very thin gauge high performance steel ("piano wire") can exceed this slightly (428MPa/(g/cc))
Are units like MPa or psi not commonly understood by the science-curious public?
Well no, nor is the term "strength". Is it yield strength, fracture toughness, youngs modulus, etc, etc? Is that tensile, compression or shear you are talking about? Carbon fibre is strong, but how about if you hit it with a brick, then normal wood is "stronger". And then there is anisotropic behavior...
This stuff is complex.
There's so many ways to look at timber strengths, and the article lightly covers how their process increases different facets:
> The team’s compressed wood is three times as dense as the untreated substance, Hu says, adding that its resistance to being ripped apart is increased more than 10-fold. It also can become about 50 times more resistant to compression and almost 20 times as stiff. The densified wood is also substantially harder, more scratch-resistant and more impact-resistant
I'm not sure if Specific Strength is something I've ever encountered wrt timber, because it depends on its use whether its compression, elasticity, hardness, or other that determines whether it's good for a specific use. That said, in my country we typically use F numbers, which are (I think) based around a loose series of terms related to stress.
That said "stronger than steel" is what ironbark is renowned for. My brother, a cabinet maker, just made some furniture form the stuff and before the job, his thicknesser and jointer blades were pristine. Afterwards, they're badly chipped. Sparks literally fly when machining this stuff.
...an egregious and tortured alternative to using actual units. They made it coffee table sized? They made it book sized? Do all "coffee-table books" come in the same size? Are they using the coffee-table coffee-table book from Seinfeld?
It's worse than a "Library of Congress" quantity of information, or a "football field" of land area.
Would it be so hard just to say "square centimeters", or the more America-friendly "square inches"?
You could probably make a bottle jack press for step 5, this is probably the most obvious limiting step for size without access to industrial equipment though
>Perhaps most importantly, the densified wood is also moisture-resistant: In lab tests, compressed samples exposed to extreme humidity for more than five days swelled less than 10 percent—and in subsequent tests, Hu says, a simple coat of paint eliminated that swelling entirely.
This is an improvement, but it doesn’t appear to solve the fundamental problem: rain. In practice most structural materials must survive exposure to not just humid air but liquid water — this is why Sorel cement is not used in construction, for example.
Wicking can be a bitch, and some wood products do not bounce back. Wet a 2x4 and as long as you dry it before rot sets in, good as new. Fiber board, at the other end of the spectrum, ruined forever. There are a lot of things in between.
So they said paint prevents swelling but they don't say what happens to the swelled wood after it dries.
Some woods are ok with rain - I've used cypress for outdoor signage for instance and it takes rain well - no warping or that sort of business. If you constrain expansion to one or two dimensions it might be ok.
"The material does not protect quite as well as a Kevlar sheet of the same thickness—but it only costs about 5 percent as much" - Incredible. Millions could be saved to protect the military and police. Additionally it could provide less weighty armor and improve performance. There has been a lot of talk about the weight of full military body armor, and I wonder how much this new material would weigh, and if comparable to kevlar but lighter, could improve performance. https://www.military.com/daily-news/2018/09/25/army-body-arm...
It's almost certainly heavier than the kevlar equivalent. It might be a good material for quickly building fixed fortifications though, or more cheaply armoring vehicles.
"Stronger than (some low ball grade of) steel" is not a unit as it's super easy to sandbag the thing you're comparing to and mislead people about how important the development is.
Are units like MPa or psi not commonly understood by the science-curious public? Why would someone like Scientific American not use actual units? This stuff is taught to basically everyone in high school.
(Maybe this is just the graduate student instructor in me, but it bothers me to no end that regular units are not used...)
EDIT: The paper does, of course use proper units (annoyingly, not in the abstract...).
The densified "super wood" gets a specific strength (strength per unit density) of: 422.2 ± 36.3 MPa/(grams/cm^3).
It is an impressive figure. State of the art carbon fiber is ~3900 MPa/(g/cm^3), though, and lots of other fibers are higher than this "super wood" (including the best grades of Balsa, I believe).
Very thin gauge high performance steel ("piano wire") can exceed this slightly (428MPa/(g/cc))
Good list: https://en.wikipedia.org/wiki/Specific_strength