Author Topic: Fun for nerds  (Read 171093 times)

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Offline T3sl4co1l

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Re: Fun for nerds
« Reply #475 on: April 20, 2023, 07:01:54 pm »
I know water, too, can be shaped with high voltage (electrowetting).  Makes me wonder if water can be piezoelectric, too.   ???

If so, might explain why a hit in the head can knock out one unconscious:  it's the electric shock generated by the piezo-water inside the brain.  ;D

There was someone making electrically-controlled focus-tunable lenses, where the focal distance of a single lens was controlled by a voltage, no motors, based on electrowetting.  Thought his electro-lenses were oil based IIRC, a French guy some 10 years ago or so.

But that's a surface effect -- not bulk.  Field strength modifying surface tension at the boundary makes sense.  (Most dramatic example: alkali metals apparently explode with a transitional hedgehog state, massively increasing the surface area in an instant!)  Or even more mundane: force deflecting an elastic diaphragm; a condenser mic (or the inverse).

Bulk doesn't make much sense, because both the force and the charge can just redistribute.  Or it ain't a liquid!

I suspect they've got some kind of gel phase, or something rheology, or maybe liquid crystal something, going on, so it's sorta liquid but not; or it's a dynamic effect, and only works on time scales above the dipole relaxation rate (which happens to be unusually low in the material, at the temperature tested).  But the article doesn't really say anything about that...

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Offline Nominal Animal

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Re: Fun for nerds
« Reply #476 on: April 20, 2023, 07:36:14 pm »
Makes me wonder if water can be piezoelectric, too.
Snowflakes are triboelectric.

If so, might explain why a hit in the head can knock out one unconscious:  it's the electric shock generated by the piezo-water inside the brain.  ;D
No, it's typically the brain hitting the skull knocking neurons off-kilter, with unconsciousness resulting from the brain shutting down unnecessary operation to protect itself.

Besides, while cerebrospinal fluid is 99% water, it has a lot of other stuff too.  Its properties differ quite a bit from water.
 
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Online RoGeorgeTopic starter

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Re: Fun for nerds
« Reply #477 on: April 20, 2023, 08:40:42 pm »
Indeed, we are more like walking bags of seawater.  ;D
Stepped out of the oceans once, wondering on land since.

Offline NiHaoMike

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Re: Fun for nerds
« Reply #478 on: April 20, 2023, 10:19:08 pm »
No, it's typically the brain hitting the skull knocking neurons off-kilter, with unconsciousness resulting from the brain shutting down unnecessary operation to protect itself.

Besides, while cerebrospinal fluid is 99% water, it has a lot of other stuff too.  Its properties differ quite a bit from water.
Handegg (incorrectly called "football" in the US) is under criticism for causing brain damage.
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Offline Nominal Animal

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Re: Fun for nerds
« Reply #479 on: April 21, 2023, 10:46:01 am »
No, it's typically the brain hitting the skull knocking neurons off-kilter, with unconsciousness resulting from the brain shutting down unnecessary operation to protect itself.

Besides, while cerebrospinal fluid is 99% water, it has a lot of other stuff too.  Its properties differ quite a bit from water.
Handegg (incorrectly called "football" in the US) is under criticism for causing brain damage.
The density of the cerebrospinal fluid is such that the brain is very close to neutrally buoyant, i.e. "weightless" within our skulls.  It really cannot support even its own weight without the fluid; and overpressure is similarly deadly.  Trepanation is one of the oldest surgeries known from prehistoric findings, and skulls that show significant healing (years, even decades) after trepanation are not rare.  There is sufficient evidence and historical record to show that this was not a religious practice, but a therapeutic one, applied to specific types of head wounds.

There are brain specialists who believe boxing with gloves is more dangerous to humans than barehanded boxing, because the gloves let humans hit much harder than they can barehanded.  It would be interesting to compare handegg and rugby statistics, as the difference is somewhat similar.

Falling on your face or back on sand or grass is unlikely to do much damage (unless you twist your limb or fall on top of something), but falling on concrete or asphalt and hitting your head can easily kill you.  The exact acceleration profile matters; it is not a total energy or momentum transfer thing.
 

Online RoGeorgeTopic starter

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Re: Fun for nerds
« Reply #480 on: April 21, 2023, 11:18:50 am »
Have had a former rugby player as a coworker at some point.  He told us it's even tougher than it seems.

The impact from falling is not the worst, from what told us once at a beer.  During a fall, there still is plenty of time to react.  The worst are those actions you don't have time to react.  For example, he was telling how an action as simple as grabbing one's arm while running from opposite directions can have a tremendous impact.  The initiator knows what action will perform next and prepares for it, while the other dude don't.  The effect is that there is no time to react, the body turns from the momentum of grabbing, then suddenly stops.  My understanding was that the effect of such a grab would be similar with that seen in the tip of a whip.  He said he would prefer a hit in the face in a fist fight, rather than that shock that propagates through the entire body during an unforeseen grab at rugby.

Online RoGeorgeTopic starter

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Re: Fun for nerds
« Reply #481 on: April 29, 2023, 09:55:08 am »
The Wooden Transistor  :wtf:


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Online RoGeorgeTopic starter

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Re: Fun for nerds
« Reply #482 on: May 07, 2023, 12:21:46 am »
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Re: Fun for nerds
« Reply #483 on: May 07, 2023, 02:17:22 pm »
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Re: Fun for nerds
« Reply #484 on: May 10, 2023, 06:48:16 pm »
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Re: Fun for nerds
« Reply #485 on: May 11, 2023, 12:37:46 pm »
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Re: Fun for nerds
« Reply #486 on: May 12, 2023, 08:25:20 am »
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Re: Fun for nerds
« Reply #487 on: May 12, 2023, 08:32:56 am »
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Re: Fun for nerds
« Reply #488 on: May 13, 2023, 02:25:37 pm »
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Re: Fun for nerds
« Reply #489 on: May 14, 2023, 08:12:44 am »
Euler's Formula Beyond Complex Numbers
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Re: Fun for nerds
« Reply #490 on: May 17, 2023, 10:32:57 am »
How Kodak Punches 384000 HOLES A MINUTE in Film Stock (Kodak Factory Tour Part 3 of 3) - Smarter Every Day 286
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Online RoGeorgeTopic starter

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Re: Fun for nerds
« Reply #491 on: May 18, 2023, 08:47:23 am »
What is the Riemann Hypothesis REALLY about?
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Re: Fun for nerds
« Reply #492 on: May 24, 2023, 07:06:16 pm »
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Online RoGeorgeTopic starter

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Re: Fun for nerds
« Reply #493 on: May 28, 2023, 08:47:06 am »
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Online RoGeorgeTopic starter

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Re: Fun for nerds
« Reply #494 on: June 07, 2023, 05:54:31 am »
The Largest Civilization in The World
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Online RoGeorgeTopic starter

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Re: Fun for nerds
« Reply #495 on: June 08, 2023, 05:58:33 am »
A Tesla coil with only three components!
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Offline Infraviolet

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Re: Fun for nerds
« Reply #496 on: June 08, 2023, 02:34:29 pm »
Does that count as a Tesla coil? It doesn't seem to be generating any arcs.
 

Online RoGeorgeTopic starter

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Re: Fun for nerds
« Reply #497 on: June 10, 2023, 01:07:44 pm »
Yea, doesn't shoot sparks, maybe in the dark, with a very thin sharpen end loose wire, IDK.  :-\
Still cool that it needs an "EMP" to crank-start it, though.  ;D

Online RoGeorgeTopic starter

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Re: Fun for nerds
« Reply #498 on: June 10, 2023, 01:08:57 pm »
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Online RoGeorgeTopic starter

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Re: Fun for nerds
« Reply #499 on: June 13, 2023, 06:21:42 pm »
Here's a Question! - Why Does the Water Rise?
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