Folding Paper with a Hydraulic Press
medium.com
medium.com
Nitpicking: my book on paper-making talks about fiber, "filler" and "glue" as the main components in any paper or cardboard sheet.
The type of fiber results in different qualities based on source material (types of wood, cotton, etc) and fibre length - every time paper is recycled the fibers get shorter, and less "fluffy". This is why toilet paper from recycled paper is coarser; it's also why toilet paper inherently wastes good fibers: the good stuff is made from fresh fibers. On the other end we have stuff like the paper used in newspapers. Eventually, the fibers get so short they can only be used for the type of brittle cardboard pulp you see in egg carton.
Combined with fiber length, filler materials determine characteristics like how porous paper is, or how stiff. Glue.. well, should be obvious what that does, and how different types and quantities affect paper.
None of this matters for Gallivan’s Theorem, other than perhaps the variation in compressibility that different paper types have. It might have an influence on the whole fusing-into-a-slab thing though.
[0] http://www.goodreads.com/book/show/2665596-the-complete-book...
I guess the book I mentioned just categorised things differently - I think the "glue" bit was mainly about water resistance and general durability. Then again, it's been years since I've read the book (and I don't have it with me to check it right now), so I might be misremembering it.
Either way, I admit that "chemical additives" would make more sense as a general label! I mean, adding a chemical to make paper fire resistance can't be called filler or glue.
I had figured that the most plausible explanation was that elastic energy was systematically getting stored in the folds, largely because the folds were at right angles to each other (hence each one is a "spine" which forces the sheet to "stretch" to accommodate it). A prediction of this hypothesis is that a book would not catastrophically fail until a much higher pressure, and that it might fail like other objects do, by eventually squirting outward like putty.
It's possible that a hybrid approach is needed: this failure seems like a release of stored energy; this explanation needs to account for the energy storage in the cellular matrix (probably not that complicated) and then we have a ready explanation of why there is a catastrophic failure whenever the hydrogen bonds themselves begin to rip (as all the stored energy is released at once).
You make a good point and I think it's both things, actually. 1) The bonds in the paper fracture 2) The elastic energy in the press causes the cylinder to drive downward, splattering the malformed paper in all directions 3) Which makes room for the cylinder to make it most of the way through the book.
That whole channel is full of interesting things being flattened.
There were even already real discoveries made thanks to youtube and patreon (for example http://www.nature.com/news/sodium-s-explosive-secrets-reveal... ).
Is this the same as video games getting children interested in programming? Is that how it works, or do kids turn to programming because they want to make video games? If the latter then there's not much value at all in these channels. No one learns computer science from watching Call of Duty videos.
That's why the GP is saying Thunderfoot's science stuff.
Thunderfoot made some videos on youtube sponsored by patreon. He was experimenting with alkalic metals, and discovered that the reaction can't be driven by the hydrogen reacting as it was usually explained. He went on to work on that in lab with coleagues, wrote a paper and got published in Nature. It seems like science to me, and it was crowdfunded, that's what got me excited, because it could be used to fund research that's hard to get funded by traditional means ("is cool" is a different motivation than "is useful", so there may be many low hanging fruits). The more angles the better.
As for education - it won't replace theorethical lessons, but I think it's useful to see real experiments to develop intuition about how the theories play out in real life, how the quantities look like, what's realistic and what's not. Even with the RHNB which I agree is mostly entertainment - school physic lessons often don't allow me to predict the result of a given video. Yes it's most probably useless for my life, but so are most of the lessons I had in school. I like having the intuition about how everyday stuff behaves in extreme conditions. It's the difference between knowing that water can freeze, and seeing winter for yourself.
It's that part that was the most jarring hole in physic and chemistry lessons I had (we almost never got our hands dirty, and even if we did - it was done so fast that usually nobody got the experiments right, and there was no time to work out why for everybody, so teachers just moved on). And the stuff used in school experiments were "magical" ingredients that you wouldn't know where to get, and how to handle.
I envy the kids today that they can just look up "how to make sugar+saltpeter rocket". When I was a kid I tried it many times and it never flied (no textbook mentioned you have to have fresh dry saltpeter, or that you can dry old saltpeter in electric owen - it was just a formula and warning that could as well mean "burning 1 gram will destroy your home" or "burning 1 kg will be slightly inconvenient").
https://www.youtube.com/watch?v=2SY6PlbJz0Q
My guess, he's not so much folding it as reshaping and mixing the metal under intense pressure in much the same way you might work dough ... (yeah, bad analogy... )
No its a good one. Reminds me of how they made "Damascus" Steele by pounding different layers together.
Too bad aluminum is too soft for this technique to provide any advantages.
...or perhaps that should actually be tested. Would this kind of processing change the mechanical properties of aluminum in any significant way?
Someone please give this guy access to a hydraulic press, a thermocouple and an electron microscope. I want to see the evidence!
The interesting here is how they are broken, not that they break.