--- Log opened Thu Sep 22 00:00:26 2022
01:30 -!- darsie [~darsie@84-113-55-200.cable.dynamic.surfer.at] has joined #hplusroadmap
04:33 -!- yashgaroth [~ffffffff@2601:5c4:c780:6aa0::1909] has joined #hplusroadmap
05:05 -!- mirage335 [~mirage335@2a01:4f8:120:2361::1] has quit [Quit: Client closed]
05:05 -!- mirage335 [~mirage335@2a01:4f8:120:2361::1] has joined #hplusroadmap
05:51 < kanzure> so after DNA barcoding FISSEQ microscopy-by-DNA-sequencing where are all the cool ideas or have those labs already exceeded their allotment
05:51 < kanzure> or is the absence of marblestone from their groups enough to stop the dissemination of absolutely bonkers science
06:05 < kanzure> .tw https://twitter.com/LukeDashjr/status/1572932453408411650
06:05 < saxo> @kanzure @MarkFriedenbach Same as a traditional decompiler, but draw from public code to guess at comments, variable names, choose between interpretations of the decompiled logic, etc (@LukeDashjr, in reply to tw:1572932141876449284)
06:13 < kanzure> https://phys.org/news/2022-09-alphafold-ai-excels-proteins.html
06:27 < kanzure> did anyone do a backup of thang010146 videos?
06:38 < nsh> "It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so." -Mark Twain
06:39 < nsh> (regarding ML/heristic-assisted decompilation. most time is lost in debugging due to misapprehension rather than nescience.)
06:50 < kanzure> babbage analytical engine visualization and walkthrough https://www.youtube.com/watch?v=_fyUtU6LVNY
06:50 < Muaddib> [_fyUtU6LVNY] Babbage's Analytical Engine: Overview (13:27)
06:59 < kanzure> .wik The Thrilling Adventures of Lovelace and Babbage
06:59 < saxo> "The Thrilling Adventures of Lovelace and Babbage: The (Mostly) True Story of the First Computer is a steampunk graphic novel written and drawn by Sydney Padua." - https://en.wikipedia.org/wiki/The_Thrilling_Adventures_of_Lovelace_and_Babbage
07:00 < kanzure> "The setting describes an alternative historical reality[6] in which Ada Lovelace and Charles Babbage have actually built an Analytical Engine and use it to "fight crime" at Queen Victoria's request.[7]"
07:18 -!- mirage335 [~mirage335@2a01:4f8:120:2361::1] has quit [Quit: Client closed]
07:18 -!- mirage335 [~mirage335@2a01:4f8:120:2361::1] has joined #hplusroadmap
08:42 < muurkha> luke-jr's idea there is pretty cool actually
08:42 < saxo> muurkha: <sbp> https://www.cs.dartmouth.edu/~sws/pubs/bbss13.pdf
08:45 < muurkha> docl: you can in fact cut rocks with just some stupid dirt glued on a stupid string, usually even if it's a pretty hard rock like granite.  it just takes orders of magnitude longer
08:46 < muurkha> and you have to replace the string a lot
08:47 < muurkha> basalt is not volanic glass with other minerals mixed in; it's fully crystalline
08:47 < muurkha> what defines glasses is not being crystalline
08:47 < superkuh> I've read all the lovelace and babbage comics. Pretty good.
08:48 < muurkha> shit will not in fact work, at least not mammalian shit; it doesn't contain quartz or anything harder, while dirt does
08:49 < muurkha> all that fancy pyramid builder stone cutting stuff was evidently done with desert sand as an abrasive, driven by copper saws and tube drills
08:51 < muurkha> "a little binder" is underspecified; how much stress your binder can support will make a big difference in how slowly you grind
08:53 < muurkha> some composites include a very large fraction of binders.  portland-cement concrete is something like one-quarter cement, and lots of polymer filled systems are less than half "filler"
08:53  * L29Ah would expect pyramid stones (granite and basalt, at least) to be more effective at grinding copper than copper at grinding stones
08:56 < muurkha> if you let contact with rocks sinter your coating into glass it will stop being able to cut rocks because it will lose its sharp points, and also the glass is softer
08:57 < muurkha> also just the regular abrasion process will tend to knock the corners off your grit after a while and you will need to replace it with fresh grit.  similarly, the string fibers will get progressively cut by the grit
08:59 < muurkha> L29Ah: copper itself is indeed totally ineffective at grinding granite and basalt, but it's also plastic enough that it resists being ground pretty well
09:01 < muurkha> the quartz sand is what did the grinding, and it evidently abraded both the copper and the stone; the cuts are in many cases contaminated with oxidized copper dust.  but, as it turns out, it grinds the granite and basalt away a great deal faster than it grinds the copper tool
09:02 < muurkha> alternative historically plausible tool materials such as bronze, wood, and hollow-stemmed bamboo-like reeds did not work as well
09:03 < muurkha> if you try to glue dirt to a string with methylcellulose you will find that the methylcellulose doesn't work any better than just water for grinding stone with the dirt
10:04 < nmz787> """Van der Waals, dipole interactions, quadrupole interactions, π-π interactions, hydrogen bonding, and halogen bonding (2-127 kJ mol−1)[10] are typically much weaker than the forces holding together other solids: metallic (metallic bonding, 400-500 kJ mol−1),[4] ionic (Coulomb’s forces, 700-900 kJ mol−1),[4] and network solids (covalent bonds, 150-900 kJ mol−1).[4][10] Intermolecular 
10:04 < nmz787> interactions, typically do not involve delocalized electrons, unlike metallic and certain covalent bonds."""
10:04 < nmz787> from
10:04 < nmz787> .wik Molecular solid
10:04 < saxo> "A molecular solid is a solid consisting of discrete molecules. The cohesive forces that bind the molecules together are van der Waals forces, dipole-dipole interactions, quadrupole interactions, π-π interactions, hydrogen bonding, halogen bonding, London dispersion forces, [...]" - https://en.wikipedia.org/wiki/Molecular_solid
10:05 < nmz787> was just reading about crystals and glasses yesterday
10:06 < superkuh> http://erewhon.superkuh.com/library/Chemistry/Crystals_%20Growth,%20Morphology,%20and%20Perfection_%20Ichiro%20Sunagawa.pdf
10:07 < superkuh> My favorite book on the subject. A mix of technical and non-technical. Fun and well written.
10:09 -!- mirage335 [~mirage335@2a01:4f8:120:2361::1] has quit [Quit: Client closed]
10:10 -!- mirage335 [~mirage335@2a01:4f8:120:2361::1] has joined #hplusroadmap
10:12 < muurkha> how strong does an electrical field need to be to ionize hydrogen molecules without any previous energetic particles?
10:38 < L29Ah> muurkha: https://en.wikipedia.org/wiki/Dielectric_gas
10:48 -!- mirage335 [~mirage335@2a01:4f8:120:2361::1] has quit [Quit: Client closed]
10:48 -!- mirage335 [~mirage335@2a01:4f8:120:2361::1] has joined #hplusroadmap
10:55 < muurkha> that isn't helpful because it is talking about avalanche discharge situations, where charged particles from a previous ionization are being accelerated
10:56 < muurkha> I'm talking about the case where the pressure is so low that you're way up the negative slope of Paschen's curve because the mean free path is much longer than the distance between electrodes
10:58 < muurkha> and, in particular, near the *positive* electrode, so field electron emission from the electrode surface isn't available as a source of previous energetic particles
11:30 < L29Ah> > where charged particles from a previous ionization are being accelerated
11:30 < L29Ah> there are no originally charged particles during the start of an electric breakdown afaiu
11:31 < L29Ah> but yes the situation at much lower pressure is different, i don't know what to use there, somehow utilize the atom ionization energy and distance?
11:35 < muurkha> there normally are, whether from cosmic rays, natural radioactivity, or photoemission from the electrodes
11:41 < muurkha> that's why you can use dark current to measure radioactivity levels
11:41 < muurkha> but presumably at a high enough field you don't need that
11:50 -!- spaceangel [~spaceange@ip-78-102-216-202.bb.vodafone.cz] has joined #hplusroadmap
11:57 < docl> basalt isn't a glass in basalt fiber? interesting!
11:58 < docl> thanks for the analysis, muurkha! I'm still evolving my ideas about this concept
12:05 < docl> I'm thinking the basic features are tensile core + ablative layer that uses dirt/rock dust. preventing the core from getting minced too quickly is mainly a cost effectiveness boundary, as you can apply more fiber while the system is in operation. one form I found fiberglass readily available in is cloth tape, which could be laminated with the crude dust based ceramic. a layer of softer material between 
12:05 < docl> might also help avoid the cutting affecting the fiber
12:08 < L29Ah> see also: https://en.wikipedia.org/wiki/Wire_saw
12:10 < muurkha> I think basalt *fiber* actually *is* a glass
12:11 < docl> ahh, that was what I originally meant
12:13 < muurkha> okay, but even basalt fiber is not volcanic ;)
12:14 < docl> yeah I should have been more clear. it's a volcanic mineral (which is crystalline) that works as feedstock for a glassy fiber
12:14 < muurkha> I mean, yes, basalt is volcanic.  but basalt fiber is made from basalt in a factory
12:14 < muurkha> yes
12:15 < muurkha> I don't have a good understanding of why basalt fiber is stronger than conventional glass fiber
12:15 < docl> the main issue with water as binder is that it doesn't immobilize the powder wrt the fiber much. I wonder how quickly ice would melt in this context? could limit it to sublimation by evacuating, but that's likely too expensive
12:16 < muurkha> yeah, I wasn't saying water was a good binder
12:16 < muurkha> I was saying it was a bad one
12:16 < muurkha> for the purpose of abrasive wire saws
12:16 < docl> I was also thinking dry ice, but that's going to sublimate fast with all the friction. maybe if you use enough it could cool the sides of the tunnel enough to help for a reasonable distance?
12:17 < muurkha> and that the methylcellulose you were linking to was pretty much just as bad as water for that purpose
12:17 < docl> gotcha
12:18 < docl> but water is way cheaper so "is it *too* bad" is a viable question
12:18 < muurkha> I was going to mention pottery, which is what the methylcellulose in question is meant for
12:18 < docl> I've also seen dextrin mentioned, but I suspect it has the same issue
12:19 < muurkha> in pottery the main binder is clay
12:20 < muurkha> it's common for clay composes actually the majority of a clay body
12:20 < docl> isn't clay what we want to bind in this context? finely ground rock
12:20 < muurkha> *to compose
12:20 < muurkha> clay is not finely ground rock, that's silt
12:21 < docl> difference is composition?
12:21 < muurkha> clay is hydrophilic phyllosilicates
12:21 < muurkha> it's true that the grains of clay are pretty small, but that's not what makes it plastic
12:22 < muurkha> its plasticity comes from liquid water layers intercalated between those nanometers-thick grains
12:22 < docl> for homogenous mineral dust would that form be common enough to assume present, or would it need to be added?
12:22 < muurkha> it depends a lot on where you are
12:23 < muurkha> also, on what you're doing with it!
12:24 < docl> I wonder if the grinding tends to break the plates, or could be optimized to form more of them
12:24 < muurkha> when aluminosilicates spurt out of a volcano or intrude as magma, they aren't clay; under those conditions water is driven out of them
12:24 < muurkha> forming clay from anhydrous aluminosilicate rock requires a (generally long) process of chemical weathering with water
12:24 < muurkha> at something close to room temperature
12:25 < muurkha> so you will not find clay in basalt or on the moon or probably on mars
12:26 < muurkha> but the point I was going to make about clay is that pottery is another example of a composite where the binder generally forms the absolute majority of the material
12:26 < muurkha> well, unfired pottery anyway!
12:26 < muurkha> not always, but usually
12:27 < muurkha> it's almost never 100%, though; to get your pottery to dry and fire without cracking you usually need to add some "filler"
12:28 < muurkha> called "temper" by potters
12:28 < muurkha> quartz is a common temper, but chamotte is another
12:28 < muurkha> if you take this to the extreme, you get greensand
12:28 < muurkha> which is used for sand casting of cast iron
12:29 < muurkha> it's about 95% sand (usually quartz rather than something exotic like olivine or sapphire) with about 3% bentonite clay as a binder
12:30 < muurkha> though I guess https://en.wikipedia.org/wiki/Sand_casting#Green_sand says I'm wrong about that
12:31 < muurkha> more like 5-11% bentonite, I guess I was thinking of sodium-silicate-binder casting
12:33 < muurkha> anyway my point is that generalizing about binder/filler composites is hazardous
12:34 < docl> yeah but the possibility space being broad means you can iterate and find the best option
12:34 < muurkha> you can find composites like waterglass-bound sand where the binder may be as low as 3%, and composites like bentonite-filled polymer systems where the binder is something like polyethylene terephthalate and bentonite appears again but this time as a functional filler rather than a binder
12:35 < muurkha> and everything in between
12:35 < muurkha> oh, and you were wondering if milling clay reduces the size of the crystals, and I think the answer is that it generally does not
12:40 < muurkha> where do you live?
12:41 < docl> Idaho
12:41 < muurkha> you can get abrasive wire hacksaw blades for cutting ceramic tile at the hardware store
12:46 < docl> I wonder if that could be incorporated into a line without needing kilometers of the stuff. say have a few segments that chip a little rock every time they sweep over it
12:52 < docl> maybe detect this happening acoustically to trigger back and forth sawing for a bit instead of continuously feeding the belt
12:55 < muurkha> interesting idea
13:04 < docl> for clay laminated fiberglass tape we're kind of talking additive mfg to begin with. I wonder if diamond dust (or rock chips/other grit) incorporated into the surface while the clay layer is plastic would stay there for long
13:08 < docl> I could picture a process where a layer of clay and grit gets applied continuously, at roughly the same rate it gets worn away. this would be with the belt going through a linear tunnel and back across the top. so if the layer is thin enough to fire quickly you could pass it through a hot cylinder
13:18 < docl> not sure firing it is actually doable given fiberglass. just drying it with hot air should be though
13:21 < docl> for a surface layer you can do brief high temperature bursts, but that's harder if the laminate layer is thin
13:25 < kanzure> https://web.archive.org/web/20070819123704/http://lists.syntheticbiology.org/pipermail/discuss/2007q2/thread.html
13:25 < kanzure> didn't realize xp_prg was around back then..
13:34 < kanzure> eugen leitl, perry metzger, drew endy, paras chopra, tom knight, sri kosuri, lots of familiar names.
14:07 < kanzure> 2008-03-10 21:26:41) fenn> the fastest way to jump start bio-MNT would be to piece together a DNA write enzyme, a sort of reverse sequencer
14:07 < kanzure> fenn> flash different colored lights for the four bases (and another wavelength for synchronizing)
14:10 < nmz787> the thesis on BAG (berkeley analog generator) is really good
14:10 < nmz787> this one https://www2.eecs.berkeley.edu/Pubs/TechRpts/2019/EECS-2019-23.html
14:10 < nmz787> I got about 3/4 through it last night
14:18 -!- mirage335 [~mirage335@2a01:4f8:120:2361::1] has quit [Quit: Client closed]
14:19 -!- mirage335 [~mirage335@2a01:4f8:120:2361::1] has joined #hplusroadmap
14:45 -!- spaceangel [~spaceange@ip-78-102-216-202.bb.vodafone.cz] has quit [Remote host closed the connection]
15:40 < docl> for cryonics, one idea I have is to exploit compression and expansion of diamond in perfusable micromachines as a rapid heat removal mechanism
15:50 < docl> for example: you could have diamond microspheres with a shaved flat edge. hydrogen tends to bond to the surface whether you want it or not, so the flats could be pressed together while still being mobile. add ferrous iron and encapsulate in a diamond track. when a high intensity magnetic field is applied, they roll to make the round edges press together and deform, releasing heat. then perfuse while 
15:50 < docl> under the field, and switch it off. returning to the unstressed shape, they absorb heat
15:50  * L29Ah throws feces at docl
15:50 < docl> got a problem L29Ah?
16:26 < docl> I don't really get why people think they gotta be like that. oh well. 1day ignore for now, maybe longer next time
16:49 -!- mirage33570 [~mirage335@2a01:4f8:120:2361::1] has joined #hplusroadmap
16:53 -!- mirage335 [~mirage335@2a01:4f8:120:2361::1] has quit [Ping timeout: 252 seconds]
16:59 -!- Guest7 [~Guest7@d164-15.icpnet.pl] has joined #hplusroadmap
17:01 -!- Guest7 [~Guest7@d164-15.icpnet.pl] has quit [Client Quit]
17:03 -!- test_ [flooded@gateway/vpn/protonvpn/flood/x-43489060] has joined #hplusroadmap
17:06 -!- _flood [flooded@gateway/vpn/protonvpn/flood/x-43489060] has quit [Ping timeout: 265 seconds]
17:09 < kanzure> docl: did i ever rant at you about how i think genetics should play a bigger role in cryonics research
17:09 < kanzure> some biologies are just going to be more or less susceptible to vitrification and resuscitation from extraordinary states of deanimation
17:18 < docl> yeah I think so. you were talking about selectively breeding mice or rats
17:19 < docl> I think it would go faster to select for cryoprotectant toxicity resiliance (some work was done on this a while back)
17:20 < docl> problem with a general pressure is there are some dead ends, like wood frogs. they do fine in a freezer as long as you don't turn the dial below something like -4C
17:21 < docl> because they have anatomical features that allow ice formation, and even cause it
17:22 < docl> but we know the thing that works best for complex tissue is vitrification, not controlled ice formation. it solves all the problems in one stroke, other than the cryoprotectant toxicity
17:25 < docl> well, osmotic damage is technically distinct, but you can avoid that by perfusing slower if you don't have toxicity to worry about. since that substantially overlaps the problem of handling ice (ice is pure water, so it pulls water across cells and this ruptures them), there might be useful adaptations in wood frogs. but this is partly just because amphibians are in and out of water their whole 
17:26 < docl> evolutionary history, not sure you could replicate that in mammals in a reasonable time
17:29 < docl> this might be it .t https://www.sciencedirect.com/science/article/pii/S0011224018302669
17:29 < docl> .title
17:29 < saxo> Genetic suppression of cryoprotectant toxicity - ScienceDirect
17:29 < docl> ok, so they used mutant mouse cells
17:32 < docl> maybe a similar approach could make mammalian cells more osmotically transmissive. not sure that would translate to adult forms well though since it's prior to cell specialization/tissue formation
17:33 < docl> I kind of like the idea of adding synthetic pores to the cell membranes. this is basically the same thing as drug delivery research, just with higher capacity in mind
17:50 < muurkha> docl: you can't fire clay quickly no matter how thin it is
17:51 < muurkha> pottery firing time is not just about what temperature things reach, it's also about how long they stay hot
17:52 < muurkha> I don't know what you mean about diamond compression.  why would you think that diamond will absorb heat upon returning to an unstressed state?
18:12 < kanzure> https://crick.com/ seems not updated since the first francis crick died
18:13 < muurkha> up the ~ without a paddle
18:13 < kanzure> and i note that the second one (according to his homepage on crick.com) went to school for computer science https://www.linkedin.com/in/francis-crick-4484221/ looool
18:13 < muurkha> I got a ~ in my neck
18:24 < docl> muurkha: my reasoning is that the entropy of the lattice becomes lower as they return to an organized state
18:25 < docl> I'm drawing a rough analogy from an explanation of the magnetocaloric effect that I read
18:28 < muurkha> why would the entropy of the lattice change?
18:29 < docl> because the bond lengths are not all the same
18:29 < muurkha> why does that affect entropy?
18:30 < muurkha> maybe my limited knowledge of thermodynamics is not up to snuff here but I can't tell the difference between that possibility and you just making plausible-sounding stuff up :)
18:32 < docl> fair enough, I'm partly not sure I'm not making plausible sounding stuff up. I could well be misunderstanding the nature of entropy as applies to a crystal
18:33 < docl> I do know compressing a gas creates heat, and expanding it cools it. if that's not true about a crystal, that's pretty interesting
18:36 < muurkha> well, not "heat" in the technical thermodynamic sense, but internal energy
18:38 < docl> so a crystal holds its shape because a specific bond length is the lowest energy state. if some are shorter and some are longer, that creates compressive and tensile forces in the direction of the initial configuration
18:38 < muurkha> I think that the amount of temperature rise from squeezing a diamond will be nonzero but only in a theoretical sense
18:38 < muurkha> because the energy you are putting in is stored almost entirely in the electric fields within the crystal
18:39 < muurkha> when you compress a gas, the force resisting your compression comes from gas molecules ballistically bouncing off your piston; if the piston is moving toward them they bounce off with more energy than they arrived with
18:39 < muurkha> more *kinetic* energy
18:40 < muurkha> when you squeeze a crystal the force resisting your compression comes from the bonds in the crystal flexing
18:41 < muurkha> mostly!  I mean the motion of the atoms as the crystal gets smaller isn't literally zero
18:41 -!- yashgaroth [~ffffffff@2601:5c4:c780:6aa0::1909] has quit [Quit: Leaving]
18:42 < muurkha> the other thing is that the total amount of energy you can put into a crystal by squeezing it is very, very small, aside from where that energy is stored
18:43 < docl> seems like squeezing a diamond 0.1% stores a lot of energy, at least as potential energy to return it to its natural shape
18:44 < muurkha> nope
18:45 < docl> like, gigapascals of pressure, even though the distance is small
18:45 < muurkha> yes, but the fact that the distance is small matters a lot
18:47 < muurkha> suppose some diamond has a Young's modulus of 1000 GPa and a compressive strength of 10 GPa.  consider a one-centimeter cube of it.  by applying 10 GPa (a meganewton) you can compress it 1%, 100 μm.  this works out to 100 J.
18:49 < muurkha> that's not a great energy density from my point of view.  it's like 30 kJ/kg
18:49 < docl> fair enough
18:50 < muurkha> well, actually it's only 50 J, sorry
18:50 < muurkha> because the meganewton isn't present for all 100 μm, it's growing linearly
18:51 < muurkha> so 15 kJ/kg.  or more precisely
18:51 < muurkha> .units 30 J / (3.5 g/cc) in kJ/kg
18:51 < saxo> G'sozulents, mochel errorsome
18:51 < muurkha> 30 J / (3.5 g/cc) in kJ/kg
18:52 < muurkha> uh
18:52 < docl> the compressive strength of diamond is 130-140 GPa and young's modulus is 1200 GPa
18:52 < muurkha> most sources give the compressive strength as around 10 GPa
18:53 < muurkha> I am aware that there is a web page at the University of Bristol that claims otherwise ;)
18:53 < muurkha> .units 30 J / 1 cc (3.5 g/cc) in kJ/kg
18:53 < saxo> 	30 J / 1 cc (3.5 g/cc) = 8.5714286 kJ/kg 	30 J / 1 cc (3.5 g/cc) = (1 / 0.11666667) kJ/kg 
18:53 < docl> I'm looking at wikipedia under yield strength, I'll check the source out
18:53 < muurkha> .units 50 J / 1 cc (3.5 g/cc) in kJ/kg
18:53 < saxo> 	50 J / 1 cc (3.5 g/cc) = 14.285714 kJ/kg 	50 J / 1 cc (3.5 g/cc) = (1 / 0.07) kJ/kg 
18:53 < docl> https://ui.adsabs.harvard.edu/abs/2005ApPhL..87n1902E/abstract
18:53 < muurkha> .t
18:53 < saxo> The strength of diamond - NASA/ADS
18:54 < muurkha> maybe it depends on whether it's natural diamond or flawless synthetic diamond
18:55 < muurkha> that's a pretty astounding result
18:55 < docl> I also found this on my last trip down the rabbit hole https://news.mit.edu/2018/bend-stretch-diamond-ultrafine-needles-0419
18:55 < muurkha> .t
18:55 < saxo> How to bend and stretch a diamond | MIT News | Massachusetts Institute of Technology
18:55 < docl> apparently they get very bendable at the nano-needle scale
18:56 < muurkha> most things do, but not necessarily stretchable
18:56 < docl> I wonder how much heat per unit volume is released in those animations
18:56 < muurkha> probably a lot
18:57 < muurkha> anyway, the resilience (maximum spring energy density) is inversely proportional to the Young's modulus
18:57 < docl> ahhh
18:57 < muurkha> and proportional to the square of the limiting stress (yield stress if there is one, otherwise ultimate strength)
19:04 < muurkha> interestingly there *is* a solid material that changes its entropy when you deform it and can consequently be used to heat things up and cool them down:
19:04 < muurkha> .t https://en.wikipedia.org/wiki/Rubber_elasticity
19:04 < saxo> "Rubber elasticity refers to a property of crosslinked rubber:  it can be stretched by up to a factor of 10 from its original length and, when released, returns very nearly to its original length.  This can be repeated many times with no apparent degradation to the rubber.  [...]" - https://en.wikipedia.org/wiki/Rubber_elasticity
19:09 < docl> basically we need to remove 4kJ per degree celsius of cooling per kg or body mass. Body temp is 35 degrees and we want to hit -135, so for 100kg body we want to remove 68MJ altogether. I'm not quite sure where the reasonable limits will be for volumetric energy density of perfusate are, maybe 1%?
19:13 < docl> so 68 MJ/kg would be nice, although higher densities change this since we really care more about volumetric density
19:14 < docl> er, volumetric energy density
19:24 < docl> I was aware of rubber's elasticity... I wonder if it generalizes? when nano-needles are deformed, does the tensile work also cause heat?
19:40 -!- darsie [~darsie@84-113-55-200.cable.dynamic.surfer.at] has quit [Ping timeout: 252 seconds]
19:45 < docl> "One may regard the entropic forces in polymer chains as arising from the thermal collisions that their constituent atoms experience with the surrounding material. It is this constant jostling that produces a resisting (elastic) force in the chains as they are forced to become straight."
20:13 < docl> so when they are coiled up, the heat has more places to go, kinda? it's touching against itself in more places because the crosslinks are all over the place, but it has to go elsewhere when it straightens out and they all get dragged parallel
20:20 -!- deltab [~deltab@user/deltab] has quit [Ping timeout: 268 seconds]
20:29 -!- deltab [~deltab@user/deltab] has joined #hplusroadmap
20:30 < docl> I wonder if surfaces just generally "tie up entropy" in contact like the crosslinks in their non-stretched state do
20:37 < docl> .t https://chempedia.info/info/force_between_polymer_coated_surfaces/
20:37 < saxo> Force between polymer coated surfaces - Big Chemical Encyclopedia
20:38 < docl> "The most important interaction is repulsive and of entropic origin. It is caused by the reduced configuration entropy of the polymer chains. If the thermal movement of a polymer chain at a surface is limited by the approach of another surface, then the entropy of the individual polymer chain decreases."
20:39 < docl> ah, maybe because the thermal energy has to go 2d more instead of 3d
20:48 < docl> so if you have a cylinder of stacked circular polymeric flakes in a good solvent, pressing them together against the repulsive force of the entropic interaction might increase heat, whereas releasing or moving them apart would absorb it
20:56 < docl> it links to a scan of a textbook called Physics of Chemistry and Interfaces
21:08 -!- L29Ah [~L29Ah@wikipedia/L29Ah] has quit [Ping timeout: 260 seconds]
23:21 -!- mirage33570 [~mirage335@2a01:4f8:120:2361::1] has quit [Quit: Client closed]
23:21 -!- mirage33570 [~mirage335@2a01:4f8:120:2361::1] has joined #hplusroadmap
--- Log closed Fri Sep 23 00:00:27 2022