mason3@husc9.harvard.edu (Richard Mason) (04/13/91)
I have two questions regarding electrocution:
1) Would it be possible to send a large electrical current through a human
being or other animal and have them survive without permanent damage?
The rules are: ANY amount of medical/chemical/surgical/biological work
(preparation before the shock, treatment during or immediately afterwards)
on the subject is permissible, providing it invokes only current or
probably realizable technology. Very long recuperation time is a minus,
but not absolutely disallowed. The current will only be turned on for
a short time (on the order of a few seconds) and other factors (e.g.
voltage) are not important except as necessary to maintain a high current.
On the other hand, the current must pass through the tissues of the
subject, so such tricks as surgically implanting conductors to draw
away the current, bypass the heart, etc. are disallowed.
2) How non-uniform is the resistivity of animal (human) tissue? Is there
any way to make the resistivity more uniform, or otherwise to ensure
that the current in part (1) is roughly uniform throughout the body?
The same rules as for part (1) apply.
If anybody answers (especially with positives), I'll tell you why I want
to know. (Perhaps you can guess.)
--
"These things are pure science fiction! And yet they are all true."
-M.O. Rabin
===================================================================
Richard Mason | mason3@husc9.harvard.edu | All opinions are my own.rowe@pender.ee.upenn.edu (Mickey Rowe) (04/13/91)
In article <1991Apr12.212721.519@husc3.harvard.edu> mason3@husc9.harvard.edu (Richard Mason) writes: >I have two questions regarding electrocution: > >1) Would it be possible to send a large electrical current through a human > being or other animal and have them survive without permanent damage? Do your rules allow for subsequent defibrillation? I read an article in _Medical Instrumentation_ back in '86 or '87 that spoke about electrocution (I could dig it up, but it would take a lot of work). It seems that the critical factor is timing more than amount of current. The problem is that if the current density in the heart is high during repolarization of the ventricles (the t-wave of an EKG) the heart will be put into fibrillation, and death is essentially brought on like a major heart attack. If the patient is defibrillated (e.g. another shock applied so that the whole heart is made refractory at the same time) then the person can be brought back with few ill effects. >2) How non-uniform is the resistivity of animal (human) tissue? Is there > any way to make the resistivity more uniform, or otherwise to ensure > that the current in part (1) is roughly uniform throughout the body? It's going to be pretty non-uniform, because blood vessels and other structures will provide guides for current flow... Also it will be time dependent, since the sweat on your skin, the amount of constriction of individual arterioles and venules etc. will vary enough to give significantly different values at different times. As for the second part of this question, I'd guess that you couldn't appreciably homogenize (or even isotropize--hey that's a neat word :) the resistivity while the organism was still alive. But that's just a guess. > >If anybody answers (especially with positives), I'll tell you why I want >to know. (Perhaps you can guess.) I don't think I want to know :) >-- >"These things are pure science fiction! And yet they are all true." > -M.O. Rabin >=================================================================== >Richard Mason | mason3@husc9.harvard.edu | All opinions are my own. Mickey Rowe (rowe@pender.ee.upenn.edu)
geb@dsl.pitt.edu (Gordon E. Banks) (04/13/91)
In article <1991Apr12.212721.519@husc3.harvard.edu> mason3@husc9.harvard.edu (Richard Mason) writes: >I have two questions regarding electrocution: > >1) Would it be possible to send a large electrical current through a human > being or other animal and have them survive without permanent damage? > No. Without implanting conductors the resistance of the tissue determines the energy absorbed (I*I*R). The resistance is a property of the tissue that can't be changed significantly without altering the tissue materially, and thus functionally.
larry@kitty.UUCP (Larry Lippman) (04/14/91)
In article <1991Apr12.212721.519@husc3.harvard.edu> mason3@husc9.harvard.edu (Richard Mason) writes: >1) Would it be possible to send a large electrical current through a human > being or other animal and have them survive without permanent damage? > > The rules are: ANY amount of medical/chemical/surgical/biological work > (preparation before the shock, treatment during or immediately afterwards) No problem. Just apply a conductive graphite grease over the subject's body, then immerse in a plating bath to deposit a layer of copper to a minimum thickness of at least 5 mm. Insert some copper tubing up the nose prior to plating to assure a breathing path. Then electrocute to your heart's content! :-) Well, you *did* say "ANY ... chemical preparation work". >If anybody answers (especially with positives), I'll tell you why I want >to know. (Perhaps you can guess.) Seems reminiscent of a 1930's movie where a "mad doctor" revives a convict sentenced to death by electrocution. If this is your theme, and you are striving for "reality", you should be aware that most, if not all states require by law that an autopsy follow legal execution. Larry Lippman @ Recognition Research Corp. "Have you hugged your cat today?" VOICE: 716/688-1231 {boulder, rutgers, watmath}!ub!kitty!larry FAX: 716/741-9635 [note: ub=acsu.buffalo.edu] uunet!/ \aerion!larry
mason3@husc9.harvard.edu (Richard Mason) (04/14/91)
The reason I ask about running currents through people is my idea for a
high-acceleration launch system.
It's difficult to accelerate people at great rates because they're so
soft and mushy, so human beings tend to be an acceleration bottleneck
when you're launching manned rockets or whatever. I mean, in theory
there's nothing stopping you from building a gigantic bullet and
launching it with explosives with 10000g acceleration, except that
any people you put inside will be instantly killed at launch.
The reason people cope so poorly with bullet-like accelerations is that
their bodies are accelerated non-uniformly. If you imagine yourself
sitting in the pilot seat of the aforementioned bullet ship, then at
launch the back of your seat will come rushing forward at 10000g and
push the back of your skull through your face before your body has
figured out what's happening.
If one could only accelerate every part of the body uniformly, then the
body would not be stretched or squished and our bullet ship crew could
survive ANY amount of acceleration unharmed. Uniform acceleration
occurs generally in some sort of uniform force field. For example,
a skydiver in freefall over a heavy planet would *NOT* be harmed by
his acceleration, even if the force of gravity was so great that he
was accelerating like a bullet in a rifle barrel, because the gravity
is pulling on his nose and his toes and every other part of him equally.
(Disregard tidal effects.)
NOW... one way of launching things is to use an electromagnetic railgun.
You mount a conductor on rails, run a current through the conductor
perpendicular to the rails, and then turn on a magnetic field perpendicular
both to the current and to the rails. (The magnetic field can be created
by the same current that is flowing through the conductor.) The magnetic
field pushes the current-carrying conductor along the rails, potentially
very very fast.
Acceleration via railgun has the same human-squishing problems as any
other form of acceleration, UNLESS the current which runs through the
conductor (the bullet ship) actually runs through the human crew
(and not just some part of their ship). If current is passing through
the human beings, then the magnetic field will accelerate *THEM* (as
opposed to accelerating their ship, which then pushes on them) and
you could launch the bullet ship without liquefying the crew.
Of course, the crew do have to survive the current, which must be
fairly high if we want to have a decent railgun, and must be fairly
uniform if we are to solve the squashing problem at all. (It has to be
fairly uniform in space, not necessarily uniform at all in time.)
--
"These things are pure science fiction! And yet they are all true."
-M.O. Rabin
===================================================================
Richard Mason | mason3@husc9.harvard.edu | All opinions are my own.cphoenix@csli.Stanford.EDU (Chris Phoenix) (04/15/91)
In article <41087@netnews.upenn.edu> rowe@pender.ee.upenn.edu (Mickey Rowe) writes: >>2) How non-uniform is the resistivity of animal (human) tissue? Is there >> any way to make the resistivity more uniform, or otherwise to ensure >> that the current in part (1) is roughly uniform throughout the body? > >It's going to be pretty non-uniform, because blood vessels and other >structures will provide guides for current flow... A sufficiently high voltage will stay on the outside of any conductor. I think several tens or hundreds of kilovolts would do it. Of course, when you increase the voltage, you dissipate more energy... if the pulse can be *very* short, you could probably make a pulse that would flash-boil the outermost layer of skin, and then move in *very* quickly and cool the remaining skin off, for something like a second-degree burn. This is stretching the rules a bit, but it might even be possible to make the pulse go through the steam rather than the solid body, so that most of the energy dissipated would not be in direct contact with the body. You could probably maintain tens or hundreds of amps for several seconds this way, and keep the person alive afterwards. Reader's Digest had a "Drama in Real Life" a while ago that involved a person shorting out a high-tension power line for a long time (at least several seconds, I don't remember.) She got severe burns where the spark hit her, but as I recall survived with no other ill effects.
cphoenix@csli.Stanford.EDU (Chris Phoenix) (04/15/91)
In article <1991Apr13.230951.525@husc3.harvard.edu> mason3@husc9.harvard.edu (Richard Mason) writes: >The reason I ask about running currents through people is my idea for a >high-acceleration launch system. Seems I should have read the thread before posting... of course my idea won't work. Let me contribute a system of my own... put a support network in the body that reaches nearly all cells, and can be made rigid quickly. The best candidate as far as I can see is the blood system. I think it reaches everywhere except cartilege. So all you have to do is either add something to the blood that can be made very solid very quickly and then desolidified very quickly, or else grow some structure along or in the vessel walls. There are fluids that solidify when a high voltage field is applied (what a coincidence!), but they are rather un-blood-like. And chemical changes would be too slow. The structure is perhaps a better idea. With nanotechnology, it should be quite easy to build. (No smiley.) Of course, you'd have to empty the digestive system and bladder, or risk overloading the structure.
geb@dsl.pitt.edu (Gordon E. Banks) (04/15/91)
I have a better idea. Lower the temperature of the crew until they are near absolute zero. Then not only won't they be squashed, but they will become superconducting, greatly enhancing their accelleration! Thawing them out live again is a trivial technical problem compared to the one of surviving electrocution, as freezing does less damage than burning.
neufeld@aurora.physics.utoronto.ca (Christopher Neufeld) (04/15/91)
In article <18678@csli.Stanford.EDU> cphoenix@csli.Stanford.EDU (Chris Phoenix) writes: > >A sufficiently high voltage will stay on the outside of any conductor. >I think several tens or hundreds of kilovolts would do it. Of course, >when you increase the voltage, you dissipate more energy... if the pulse >can be *very* short, you could probably make a pulse that would flash-boil >the outermost layer of skin, and then move in *very* quickly and cool the >remaining skin off, for something like a second-degree burn. > Not quite. A sufficiently high frequency will cause the current to travel dominantly in a region near the outer surface of the conductor. At DC levels you can express the current as a function of the conductivity and potential difference across the body without having to worry about complicating time variances, and when you do you see that the conductor is permeated by a current density which is inversely proportional to the resistivity when that quantity doesn't change much over the bulk. A person's skin has a high resistivity, it's most of the 300kohms hand to hand resistance most people measure the first time they get an ohmmeter. Once under the skin the body is primarily an ionic solution in water. That has a very low resistance. DC to megahertz frequency applied voltages will not drive currents only along the skin. Most of the current will cross the skin and pass through the body to the other contact. High voltages are fatal at DC or at low frequencies (read lower than a few megahertz). It's dangerous to believe otherwise. >This is stretching the rules a bit, but it might even be possible to make >the pulse go through the steam rather than the solid body, so that most >of the energy dissipated would not be in direct contact with the body. >You could probably maintain tens or hundreds of amps for several seconds >this way, and keep the person alive afterwards. > Recall that pure water has a very low conductivity, and steam is pure water. Further, it's very difficult to get ion transfer in such a dilute medium. In general, if a gas at atmospheric pressure is conducting electricity it's probably a plasma. You don't want to be on the inside of a cloud of plasma. While steam is technically a vapour, the argument still applies. >Reader's Digest had a "Drama in Real Life" a while ago that involved a >person shorting out a high-tension power line for a long time (at least >several seconds, I don't remember.) She got severe burns where the spark >hit her, but as I recall survived with no other ill effects. And there are stories of people surviving falls of thirty thousand feet. Doesn't mean I'd like to base a passenger space launch on the principle. (That was the intent of the original question). -- Christopher Neufeld....Just a graduate student | Flash: morning star seen neufeld@aurora.physics.utoronto.ca Ad astra! | in evening! Baffled cneufeld@{pnet91,pro-cco}.cts.com | astronomers: "could mean "Don't edit reality for the sake of simplicity" | second coming of Elvis!"
neufeld@aurora.physics.utoronto.ca (Christopher Neufeld) (04/20/91)
In article <1991Apr15.124450.8266@dsl.pitt.edu> geb@dsl.pitt.edu (Gordon E. Banks) writes: > >I have a better idea. Lower the temperature of the crew until they >are near absolute zero. Then not only won't they be squashed, but >they will become superconducting, greatly enhancing their accelleration! Not all cold things are superconducting. A person cooled down near absolute zero is just brittle, not superconducting. -- Christopher Neufeld....Just a graduate student | Flash: morning star seen neufeld@aurora.physics.utoronto.ca Ad astra! | in evening! Baffled cneufeld@{pnet91,pro-cco}.cts.com | astronomers: "could mean "Don't edit reality for the sake of simplicity" | second coming of Elvis!"