Hon-Zatsu Kōmoku 107 Yuichi Masubuchi: Interesting Rheology: The Science of Sludgy, Squishy Substances

[HL: Things that flow and deform, physics mysteries, a bridge to physical magic]

This time, it is Yuichi Masubuchi's "Interesting Rheology: The Science of Sludgy, Squishy Substances".
ISBN-13: 978-4774143101
In the NDC classification, it is 428, Natural Science > Condensed Matter Physics.
Degree of prerequisite knowledge required (aversion to physics): ★★☆☆☆
There are no calculation formulas written in this book at all, but those who develop an allergy just hearing the word 'physics' might find it a bit tough.

This is a rough project where I use a random number generator to pick one book from the approximately 6,000 I have on hand to read, and while I'm at it, think about whether it can be used for a novel. Sometimes I also choose them arbitrarily.

★Index by Library Classification

1. Pre-reading impression: Yuichi Masubuchi, Interesting Rheology

This time, it's a book I borrowed from the library, which is a bit irregular. The local library had been closed for three months... Come to think of it, I don't have any condensed matter physics books in my personal collection. I wanted to look up dilatancy. I didn't take physics in junior high or high school, so I don't know much about this field, but I'll read it since I have the chance.
Supplement: Rheology is the study of the deformation and flow of matter in general. It seems it wasn't mentioned again in the main text because it's taken as an obvious premise.

2. Table of Contents and Preface Check

Reading the introduction.
Is toothpaste a solid or a liquid? Which flows more easily, mayonnaise or honey? We recognize the properties of these substances through our senses, but in manufacturing, these properties must be fixed from the perspective of ease of use, comfort, etc. This book is a collection of small trivia about rheology that deals with the flow and deformation of matter, focusing on things you would write in a column of a textbook, while things you would write in a textbook are written in the columns.
I love this kind of slightly twisted talk. But unfortunately, what I wanted to know was the kind of thing written in a textbook. However, that is surely full of calculation formulas, so this is fine for a start.
Looking at the table of contents.
"Electrorheology: Mystery Novels and Robots", "Thixotropy, Plasticity, Shear Thinning: Rheology Wrought by God", "Molecular Rheology: Snake Accelerators", "Food Rheology: Lemon for Strawberry Jam", "Extensional Viscosity: Plastic and Rice Bread", "Dilatancy and Shear Thickening: Intelligent Soccer Balls", "Rubber: Even Conflicts Dissipate", "Rheology of the Earth and Space: All Things Flow", "Healing Rheology: That Addictive Texture", "Drag Reduction Effect: The Terrifying Dolphin".
Oh man, I'm interested in all of them.
I will read "Electrorheology: Mystery Novels and Robots", "Thixotropy, Plasticity, Shear Thinning: Rheology Wrought by God", "Dilatancy and Shear Thickening: Intelligent Soccer Balls", and "Rubber: Even Conflicts Dissipate". I'll prioritize the ones that seem usable for mysteries.
As always, the first part is a summary, and the second part is my impressions and miscellaneous thoughts.

3. Contents

About "Electrorheology: Mystery Novels and Robots"

- Summary
Fluids that have the property of solidifying or changing viscosity under an electric field (a physical field generated in the surrounding space by electric charge) are called "ER fluids". The increase in viscosity occurs in a short time of about 10 milliseconds, and it is necessary to apply a voltage of several kilovolts per millimeter of distance between electrodes. This characteristic can be applied to clutches, active dampers, and robot joint control; for example, if an ER fluid is incorporated into a nursing robot, it can automatically stop its movement based on the force expected when it hits a person. Its use as a haptic presentation device (changing hardness to express texture) is also being considered.
Since the latter half of the 19th century, it has been reported that the viscosity of liquids changes due to electric fields. Liquids in which solid particles are dispersed are called "particle-dispersed ER fluids", and dielectric particles polarize (separate) under an electric field, and due to the excess of electric charge, nearby particles bond (stick) to each other, and as a result of the attraction generated between the electrodes and the particles, it is thought to act as resistance. In the dielectric sphere model, if the particles bond, it is a solid, and if they do not bond or if the bond is broken by a strong force, it is a liquid.
Liquid crystals used in displays, unlike particle-dispersed systems, only increase in viscosity under an electric field and do not solidify. It is thought that this is because particles take a structure that bridges (connects) between electrodes, but in this homogeneous ER fluid, they do not take a bridging structure. Details await further research.

ER fluids respond to electric fields, while magnetic fluids and MR fluids respond to magnetic fields. Magnetic fluids are made by covering the surface of ferromagnetic fine particles such as magnetite with a surfactant (something that changes the properties of water, oil, etc., so they can be mixed) and dispersing them in oil, etc. They were developed as sealants for spacesuits (used to fill gaps to increase water resistance and airtightness) and are currently used in fluid bearings for HDDs. Magnetic fluids enter the direction of magnetic field lines, so they form seals on their own.
MR fluids are those in which larger particles than magnetic fluids are dispersed, and the magnitude of resistance can be controlled depending on the direction in which flow is applied. Depending on the type, iron particles can act as both MR fluids and ER fluids, and can also exert a synergistic effect.
The reason these fluids are not used much in daily life seems to be the difficulty of making them into devices and cost issues, and it is thought that the cost for high-end equipment could not be tolerated due to the collapse of the bubble economy.

- Impressions
This is probably a story that has been hit directly by the trend of not spending money on basic research. Recent corporate research is mainly focused on research into methods to directly improve performance individually, and basic research that is not directly linked to business, such as research into the movement of these fluids themselves, may already be difficult in Japan.
That aside, it's a very dreamy story. The first thing that comes to mind is Patlabor, but it seems like it could be used for various mystery tricks. However, these are probably not general knowledge yet, and if you use them directly in a trick, it will hit Knox's Third Commandment: "No mechanical contrivances are to be used in a mystery, nor any scientific explanation of a machine that requires a scientific explanation."
So if I were to do it, I would have to write it casually at the beginning as the latest technology for prosthetics, but in order for the reader to quickly connect the trick and the prosthetic (example) in the solution chapter, I have to insert an explanation of the fluid somewhere casually, and this is quite troublesome. It's similar to the story of how to clear basic settings in a short sentence in SF. But these kinds of physics tricks are a dream, after all. It ends up that the culprit can only be a technician or a researcher.

Also, if I were to use it, it would be SF or fantasy. Use it as an unknown fluid. I feel like it would be interesting to make it the basic theory for a wizard to use magic. A wizard who handles particles called mana that are rampant in the air with an electric or magnetic field is quite exciting, but even if I think about it simply, I feel like it's impossible because it's too invincible.
So I need to add various restrictions from there, and assuming I need to adjust it by the distance/range of the mana I can use from myself or the attributes of the mana (fire, water, earth, wind, etc.), it's quite interesting because I've never thought about magic so physically before. It might be a concept that is compatible with settings like magical organs.

About "Thixotropy, Plasticity, Shear Thinning: Rheology Wrought by God"

- Summary
The substance called the blood of Saint Gennaro in Naples is usually solidified, but twice a year, during rituals, it returns to a liquid if you shake the small bottle slowly and bring it close to Gennaro's remains.
Phenomena where softening occurs when force is applied in this way are divided into: (1) Shear thinning, where viscosity decreases due to an increase in shear rate (the property of resisting the force of pushing away); (2) Plastic flow (irreversible deformation that occurs in a substance subjected to stress exceeding a certain limit), where it begins to flow when a force greater than a certain yield stress (stress at which the plasticity of the material begins) is applied; and (3) Thixotropy (viscosity changes over time), where stress decreases over time. However, these three have overlapping properties and are difficult to distinguish, and due to the transition of word definitions, they are mostly grouped under thixotropy.

For example, the phenomenon where viscosity decreases due to the flow of force is seen in colloidal dispersions and emulsions. A colloidal dispersion is one in which fine particles are dispersed in a liquid, and like India ink or toothpaste, if left quietly, the dispersoids in the liquid gradually gather to form a network structure called a gel, and the entire liquid maintains its shape and behaves as a solid, but if force is applied from the outside and this structure is destroyed, there is no support, so it flows (sol). Emulsions are dispersed as a mixture like milk, dressing, or mayonnaise where insoluble matter is dispersed in a liquid, and when they coalesce and coarsen, and the liquid does not coalesce due to the effect of emulsifiers, etc., the liquid wall on the medium side becomes a network, and it stops flowing due to the interfacial tension between liquids, but if an external force is applied, it is destroyed and flows.
In this case, the stress required to turn the gel into a sol is observed as yield stress and regarded as (2) plastic flow, and if the structure is gradually destroyed by flow, (3) thixotropy where viscosity gradually decreases over time is observed, and in that the degree to which the structure is destroyed differs depending on the speed of flow, (1) shear thinning where viscosity decreases due to an increase in strain rate (speed obtained by dividing the amount of deformation per unit time by the original length) is observed.

Thixotropy is easy to understand if you think about honey.
It hardens when the temperature is low, but flows when warmed. Humans demand both the property of a liquid that can change its shape immediately and the property of a solid that can remain after reaching the desired shape. An application example of this phenomenon where viscosity changes due to force or flow is gel ink ballpoint pens. Gel ink behaves as a solid in a gel state when not writing, but when force from the rotation of the ball near the tip is applied to the ink, it turns into a sol and flows.
In metal thixomolding (a molding method for magnesium alloys), heat is applied to the material to melt it, the melted material is injected under pressure like a syringe into a mold, and then it is held under pressure, cooled, and removed from the mold. In this case, if a fluid with thixotropic properties is used, the viscosity of the liquid gradually decreases due to the high shear force applied during injection, making filling easier.
For spray detergents, a property is required where the viscosity is low when dispensed and it becomes a solid after being dispensed, but surfactants spontaneously form molecular assembly structures called worm-like micelles in the liquid. Since this worm structure is a weak molecular assembly, it breaks and becomes liquid when the force of being dispensed from the spray is applied, but since it reforms immediately, it solidifies when it hits the wall. This rheology is also used in civil engineering, and when a surfactant that forms worm-like micelles (Kao's Pisco Top) is added to concrete, dispersion is suppressed when concrete is poured into water.

With the advent of toothbrushes and tube toothpaste, Lion released toothpaste that is easy to squeeze out of the tube and does not drip on the toothbrush. Currently, water-soluble polymers such as polyethylene glycol are added to maintain a transient cross-linked structure and produce thixotropy.
For paint, there is a demand that it be a liquid when painting, and a solid before and after painting (painted and dried). Cave paintings by Cro-Magnons, etc., have pigments attached to walls with animal fat or eggs. In Egyptian civilization, beeswax, gelatin, and gum arabic were used.
Modern paints include those that use organic solvents with low boiling points and fast evaporation rates, those that condense the pigment itself to gel it, and those that cause a cross-linking reaction with suitable chemicals. In the type used by thinning with solvent, the rheology of the paint itself is adjusted to be a Newtonian fluid (a fluid whose viscosity does not change when force is applied) to make it easy to paint, and there are those that prevent dripping by increasing viscosity through the evaporation of the solvent.
Paper wasps, etc., use the thixotropic properties of mud when making nests with mud. When a wasp brings mud, it vibrates its wings violently to turn it into a sol, making it easier to build a nest. A bottomless swamp is a state where fine particles of soil are dispersed in water, and if nothing is done, it looks like a solid in a gel state, but if a person or animal applies force, it turns into a sol and the body sinks.
The effect changes depending on the diameter and distribution of the particles.

- Impressions
It felt like a case report, so it dragged on and on.
I feel like this group of stories is also easy to use for physics tricks, but the force of cross-linking assumed in this item is surely very weak. But I wonder if it can be used for something.
Hmm. If I were to use it, I've started to feel like this is not physics but narrative. For example, like Gennaro, by having relics move or not move in a specific way, you could burn an impressive scene into the characters' minds and gloss over mistakes in the timeline. If you do that, it becomes a direction of creating a mysterious apparition and proving that it is scientifically possible, so it's more of a story about the elucidation of modern apparitions. Or, it's a roundabout way, like someone dying because a surfactant wasn't added (regardless of intent or negligence) when placing concrete underwater, and the grudge from that, hmm, roundabout.
It's difficult to do this in modern times where apparitions basically don't exist, and since you have to incorporate the mechanism that causes/occurs the error artificially/non-deliberately, I feel like that's troublesome in its own way.

This book is great because it uses product names as concrete examples, making it very easy to visualize. Come to think of it, Gennaro's staff appeared in the Partenope I saw the other day, and that thing turns into a liquid during rituals, right? If so, I wonder if shaking it slowly breaks the cross-links.
The book points out that since Gennaro was executed in a place where volcanic ash was falling, there is a possibility that special metals were mixed in, but I'm going to support the theory that tomato ketchup was mixed in (what am I talking about).

Regarding "Dilatancy and Shear Thickening: Intelligent Soccer Balls"

- Summary
Dilatancy is a phenomenon where viscosity increases and it behaves like a solid the faster the deformation speed applied to it. A typical example of a dilatant fluid is a mixture of potato starch and water; if you insert a disposable chopstick slowly, it goes in easily, but if you insert it quickly, there is significant resistance. It doesn't have to be potato starch; any fine powder that doesn't dissolve even when dispersed in water will do. If you spill it, it spreads and powders, but once dry, it can be vacuumed up.
If you insert a glass tube into a balloon filled with sand (wrapping the tube in cloth so the sand doesn't pass through), pour water into the tube, and squeeze the balloon, the sand moves inside the balloon, water enters the gaps, and the balloon becomes hard. Dispersed particles in a solution have weak repulsive forces acting between them, and when the particles move, they push the surrounding liquid, exerting force on the surrounding particles (hydrodynamic interaction). This sometimes acts in a direction that brings particles closer together, and it happens faster the faster the particles move.
Dilatant fluids fit the shape as a liquid when moving and are suitable for protectors that harden when they feel an impact; they are used in motorcycle gloves, ski wear, polo protectors, etc. The composition of these commercial fluids varies by company, but Delaware uses a dispersion of silica fine particles. Some are tuned so well that you can wrap an egg in the fluid and hit it with a hammer without it breaking. If soaked into Kevlar fibers, bulletproof performance increases. They are also used in sports balls, tennis rackets, and viscous couplings for motorsports.

- Impressions
Potato starch and sandy beaches are often used as examples of dilatancy, but I thought that recently, things like Yogibo might be easier to visualize.
Dilatancy seems to have high versatility. I came up with a few ideas, but since I need to combine multiple tricks to use this in a long story, I might try writing something as a short story. And I realized that the potato starch one I already wrote is a bit difficult in terms of quantity. I might have needed to spread it on a palette or something because it needs a mechanism to hold the water, but that also feels unnatural. As expected, you shouldn't write without researching. Well, it's good that I realized that.

Also, there are quite a few defensive ways to use this; for example, in a fantasy story involving technical cheats, I thought it might be possible to block bullets with gloves using dilatant fluid even though you thought you were shot. No, I should just replace that with magic, but if the premise is to replace it with magic, I'm sure people will just say you should just handle it with magic. I like logic! It feels wrong without logic.
But physics is great after all! If you use physics well, you can do more things than you think. Maybe I should have taken physics in junior high and high school, but back then I really hated calculations. I still hate them, but now I don't really have the mindset of 'I don't want to do it because I hate it.' There are things you have to do even if you hate them. I don't want to do them.

Regarding "Rubber: Even Conflicts Dissipate"

- Summary
Single-molecule measurement technology that extracts specific molecules and measures their characteristics is developing, but this technology is old and has even been found in Mesoamerican ruins. Natural rubber is a polymer solution of polyisoprene, and polymers have the property of flowing as a substance by changing their positions relative to each other through diffusion (a physical phenomenon where particles, heat, momentum, etc., scatter and spread). Since rubber tree sap alone cannot flow and maintain its shape, ancient Mesoamericans mixed in morning glory sap to cross-link the polyisoprene, binding the molecules into a single molecule, which they used as a ball. Later, Goodyear invented vulcanization, which involves mixing in sulfur and heating it to bond isoprene molecules.
Rubber has the property of deforming significantly with a relatively small force and returning to its original shape when the force is removed. Typical examples of this property are rubber bands and bicycle tire tubes.
Rubber shrinks as the temperature rises. Metal springs expand when the temperature rises, which is the opposite property. This property is used in air conditioner heat pumps, etc., but the temperature behavior regarding expansion and contraction is opposite for rubber and air.
This elasticity of rubber is called entropic elasticity. Rubber is made of polyisoprene polymers that are cross-linked, and the space between cross-linking points is connected by string-like polymers. Rubber bands undergo Brownian motion (a phenomenon where floating particles move irregularly) due to heat, and the higher the temperature, the more violently they move, but since both ends are cross-linking points, they cannot move freely, and the central part contracts.

As a physical property of rubber, it has the effect of dissipating the applied mechanical energy as heat through molecular motion. Specific examples include vibration damping, soundproofing, and seismic isolation. When water droplets fall from a high place, they don't bounce but spread out sideways, but in the case of solids, they bounce. This difference is because liquids dissipate energy as heat, while solids return it as mechanical energy.
Since rubber and polymers are viscoelastic bodies, by changing the shape of the molecules and the degree of cross-linking, they can change between liquid and solid over time, and by controlling molecular motion, the degree of energy dissipation and response speed can be controlled. Hanenite balls are indistinguishable from ordinary rubber balls in appearance, but by changing the deformation cycle, deformations as fast as 1/1000th of a second absorb vibration and do not bounce (if you lower the temperature, the molecular motion changes, so they bounce).
Rubber's energy dissipation also changes by putting solid fine particles into rubber or plastic. Mixing carbon black into natural rubber increases its strength. For automobile tires, you want rolling friction to be as small as possible (to suppress energy dissipation) and sliding friction during braking to be large (to dissipate). Since rolling resistance is a characteristic in the relatively low-frequency range and sliding resistance is a characteristic in the relatively high-frequency range, development is underway for materials that control molecular motion well to increase dissipation in the high-frequency range. There are also ingenuity such as balancing by using materials with a high degree of dissipation in parts that deform significantly during control.

Seismic isolation rubber is placed between the building and the ground to change the resonance frequency of the building, which can lengthen the natural period and prevent resonance damage. In vibration damping, high-damping rubber with a high dissipation effect is used to convert earthquake shaking into heat to reduce the impact on the building.
Rubber is a rheological substance that can balance elasticity (energy conservation) and viscosity (energy dissipation).

- Impressions
I was surprised that one piece of rubber is one molecule.
I thought about whether I could use a trick that is set up in a public building on a timer, but I wonder if the time span of the timer is too long to use. I've started to feel like I'm only seeing it as material for physics tricks. Well, a simple or direct one would be to mix Hanenite balls into a lot of rubber balls and use that for a trick, but I can't think of a situation right off the bat. However, if I know that such a substance exists, I might remember it when the time comes, so that's good.
That aside, it might be interesting to write a story about Japan taking over all the rubber plantations in Southeast Asia during the Great War and the Western world lacking rubber, but it's difficult to decide who to make the protagonist.
Rubber is a substance whose effects are easy to understand and versatile, and it has existed for a long time, so I feel it would be easy to explain if I were to create some kind of trick. The problem is that I have to come up with that trick.

Summary

I ended up reading the whole thing.
The summaries for each became long, but it can't be helped.
I summarized while looking up terms because unknown terms appeared quietly, but since I have never taken physics, I don't really understand anything beyond the concepts. On the other hand, it is interesting that physical phenomena I hadn't questioned until now have various properties more than I thought if analyzed.
Overall, it was full of physics trick material that I thought was impossible to come up with now, and it was very interesting. However, this is a physics (academic) story, so to use it in a novel, it is a prerequisite to thin out the physics feeling (?) so that even readers with a physics allergy won't feel it. There are quite a lot of people who dislike physics, or rather, the image of calculations brought about by physics. I hate them too.
As for whether it can be used in a novel, it can, but I think it's polarized depending on whether you can be interested in this field if you try to use it. These physics tricks are very attractive, but if you introduce them in a work, if there are too few hints or the explanation is too difficult when revealing the truth, you won't be able to get the catharsis of truth-seeking. This book is very easy to understand because examples come out with product names, but in the first place, physics tricks are hard to use because it becomes impossible if the writer doesn't understand them well.

4. Conclusion

I happened to borrow it, so I tried writing about it with a library book, but I realized after reading about half of it that it didn't fit the main purpose. This Book Miscellany Outline was originally for confirming the contents of books I can open immediately, and it does not include books borrowed from the library. After all, you wouldn't break into a library in the middle of the night to use it for materials for what you're writing now. For that reason, I won't use library books for this item from now on, and at the same time, I'll make a note to buy it if it's sold as a used book because I feel like it could be very useful. Since I realized this, writing my impressions this time is a total plus.
By the way, the meaning of rheology is only written on the cover (you don't usually read the comments in small letters on the cover, right?), so I looked it up, and rheology is 'rheology' in English, and 'rheo' seems to come from Heraclitus's 'panta rhei' (everything flows). But this 'everything flows' is not a story about matter flowing, but a philosophical story about the equivalence of things, so I wonder if the direction is completely different in the first place. It's fine to just call it fluid mechanics, fluid mechanics.
Next time is Da Vinci Special Edition 'Actually, I like the Heike. - The Truth of the Genpei that will open your eyes'.
And, I had planned for next time, but with the end of the tweet function, this article is expected to be the final one for the Book Miscellany Outline.
Thank you very much for reading until now!

★ Books with similar themes
Uon. I haven't read the physics stories yet. So, well, just things that seem to be facing the same direction.

★ List of magazines

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