Super Wood (2018)(scientificamerican.com) |
Super Wood (2018)(scientificamerican.com) |
"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))
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.
> 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.
For instance, here's an Oz timber that I know is pretty hard: https://ironwood.com.au/grey-ironbark-technical-specs/
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"?
I can imagine the folks who make plywood and pressure treat wood could just add another process and make a new in-demand product.
This could be an interesting Science Fair experiment:
1. Get the following from Amazon (or your favorite online store) NaoH, $14 (https://www.amazon.com/FDC-99-Pure-Sodium-Hydroxide/dp/B013K...). Also get Na2SO3, $16 (https://www.amazon.com/Sodium-Sulfite-Na2SO3-Powder-Space-Sa...) and deionized water, $24 (https://www.amazon.com/Deionized-Water-Gallon-ASTM-Type/dp/B...)
2. Get an oak block (See paper for other types of woods that can be used) from Home Depot, $14 (https://www.homedepot.com/p/Builders-Choice-1-in-x-2-in-x-8-...)
3. Place 2.5M NaOH and 0.4M Na2SO3 in a pot, boil. Place small block of oak in it. Boil for 7 hours. Of course, should do this outdoors or in a hood.
4. In a separate container bring ionized water to boil, immerse piece of wood several times in it.
5. Press wood block perpendicular to the wood growth direction at 100 °C under a pressure of about 5 MPa (~50x atmospheric pressure) for about 1 day
6. You have your super wood to test
Step 3 is possible for hard-core science fans to do at home, Step 5 is problematic for that scenario.
(45 lb / (225mm)^2 * pi * g) in psi = 1.8 psi
5 MPa / 1.8 psi = 403 plates * 1.25" in m = 12.8 meters
Prior discussion on HN: https://news.ycombinator.com/item?id=16331375
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.
It seems like the carbon cost for creating this stuff might be much less.
Didn't do well in the far East because of humidity but they cracked that later.
Brilliant bit of engineering since it used a lot of equipment/skills that where under utilised at the time they started building them.
With the F18 and the Lightning one of my top 3 favourite military planes ever.