sieve i care
john russell
in which holes could be covered or uncovered at intervals corresponding
to the integers. When you applied the algorithm and covered/uncovered
the corresponding holes, you rolled a ball down the ramp and if it
didn't fall through a hole, the number was prime. (Probably still is.)
John
--
Canada Remote Systems. Toronto, Ontario
NorthAmeriNet Host
Magnus Olsson
>The way I've seen it diagrammed, the sieve was an actual device: a ramp
>in which holes could be covered or uncovered at intervals corresponding
>to the integers. When you applied the algorithm and covered/uncovered
>the corresponding holes, you rolled a ball down the ramp and if it
>didn't fall through a hole, the number was prime. (Probably still is.)
I've also seen pictures of such `physical' sieves - they're a nice and
pedogical way of demonstrating what a prime is - but has anyone ever
seen one in real life? I suspect nobody's ever bothered to build one
(after all, to be useful, it would have to be *rather* big). The
ancient Greeks almost certainly never built any - they were far too
theoretical to build a machine to do what could be done by pure
reason...
Magnus Olsson | \e+ /_
Dept. of Theoretical Physics | \ Z / q
University of Lund, Sweden | >----<
Internet: mag...@thep.lu.se | / \===== g
Bitnet: THEPMO@SELDC52 | /e- \q
Rob Peglar
As fate would have it, the public TV station here (KTCA) showed 2001 a few days
ago. Over a few beers, I took notes. (naah, I didn't have too many, the notes are
still readable at the end :-))
Roughly chronologically through the movie, you see things like:
"IBM" on the earth-to-station shuttle consoles (for the pilot and co-pilot).
This is the first scene with a 'computer' in it - follows the 20-minute or
so famous 'monkey' intro scenes.
'Voice-print' identification used on the space station. This is one of
the technologies that is still far beyond today's capability.
Also on the space station, a 'picture-phone' system is seen. The resolution
of the picture appears to be no better than VGA; much worse than any of
the consoles shows throughout the film. The best part about this small scene
is that the entire 'phone' call (and Dr. Floyd does refer to it as a 'phone
call') costs only $1.70 - space station to Earth!!
The ten-second scene with the 'zero-gravity' toilet is a classic. Wonder
what microprocessors are used here. Can't you see the marketing guys saying,
'yeah, our micros are used in the space station toilets!!'
The earth-to-moon shuttle gives the first glimpse of the 3-D navigation
consoles. Also, this is where one first sees the three-letter acronyms
appear on the consoles. 'COM' and 'NAV' appear. Communications and navigation?
(note, the others that appear through the film are ODE, LIF, MEM, NUC, ATM,
DMG, VEH, FLX, and CNT. Any guesses?)
Finally, we meet HAL. First glimpse is of HAL's "eyeball", with an IBM-CDCish
'HAL 9000' title/overlay typeset. In the first few minutes with HAL, we learn
that he is visual, aural, and cognitive. Again, this kind of computer inter-
action with man is far beyond anything we have today, of course. But,
as previous posters pointed out, some of the other interactions are quite
crude. One example is when HAL 'detects' the AE-35 failure, Dave asks for
information, and HAL spits out a punched card! Also, after the EVA scene,
the 'failing' AE-35 unit is checked out in the pod bay. During this checkout,
we see rapidly flashing screens - of crude printed circuits!
Moving through the film, I was taken by Clarke's brilliance on describing
conflict (computer versus man), how man is so dependent on computers, yet
how so ingenious man is, compared to computers (like when Dave figures out
a way to get in after HAL won't open the pod bay doors). Could a computer
have figured out a way to get in? Foreshadowing of the massive problems
and challenges of AI?
After Dave gets in, HAL advises him to "take a stress pill". Great line.
Another example of the 1960's vintage mindset about computers is the huge
'logic-memory' center of HAL, so large that Dave actually floats around
in it, using what looks to be a modified screwdriver (!) to remove memory
modules. This is not unlike the CDC Star-100, so large that (with logic
removed), one could actually run around inside the chassis to some extent!
As HAL is 'dying' (he becomes very emotional; 'my mind is going, I can feel
it, I'm afraid') we learn that it is HAL-9000 computer, which became
operational at (what sounds like on the film) 'HAL-land', in Urbana,
Illinois, on the 12th of January 1992. HAL also says 'My instructor was
Mr. Langley'. NASA, anyone? A classic scene. The end of HAL.
Rob
--
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Internetwork Group 7600 Boone Avenue North
ro...@anubis.network.com Minneapolis MN 55428 (612)424-4888 x1028
Steven M. Stadnicki
>I've also seen pictures of such `physical' sieves - they're a nice and
>pedogical way of demonstrating what a prime is - but has anyone ever
>seen one in real life? I suspect nobody's ever bothered to build one
>(after all, to be useful, it would have to be *rather* big). The
>ancient Greeks almost certainly never built any - they were far too
>theoretical to build a machine to do what could be done by pure
>reason...
As a matter of fact, sieves (though not quite the Erastothenes sieve) have
been built and used in primality testing/factorization; one of the Lehrmers
(sp?) built one in the 1930s, I believe, based on multiple representations of
numbers by quadratic forms... I seem to recall it having some rather grand
success factoring a then-huge number... hopefully someone can come up with
more details on this than I can.
Steven Stadnicki
ss...@andrew.cmu.edu
Rick Smith
>Incidentally, Dave's successful entry was consistent with ongoing
>discussions as to how long a person could survive in a vacuum.
>(I bet his ears hurt, though. :-)
I remember going to the opening night of 2001 in the Washington
area. They gave out little 4-page pamphlets, sort of like 'programs'
with the space-station-poster picture on the front, credits on the
inside, and a brief essay on the back page of then-current theories
about people being able to survive briefly in vacuum. I vaguely
remember noticing it before the movie started and feeling a vague
foreboding. I may still have the pamphlet somewhere...
Rick.
sm...@sctc.com Arden Hills, Minnesota
Mike Tighe
>In article <1991Mar4.1...@ns.network.com>
>ro...@gumby.network.com (Rob Peglar) writes:
>>Moving through the film, I was taken by Clarke's brilliance on describing
>>conflict (computer versus man), how man is so dependent on computers, yet
>>how so ingenious man is, compared to computers (like when Dave figures out
>>a way to get in after HAL won't open the pod bay doors). Could a computer
>>have figured out a way to get in? Foreshadowing of the massive problems
>>and challenges of AI?
> Actually, HAL knew about the emergency air lock, but had
>dismissed it as unusable ("Without your space helmet, I'm afraid
>that would be rather difficult" if I remember the quote correctly).
>Incidentally, Dave's successful entry was consistent with ongoing
>discussions as to how long a person could survive in a vacuum.
>(I bet his ears hurt, though. :-)
I think HAL wins on the air lock scene. Sure, Hollywood made Dave look
smarter than HAL, but I do not believe you would last one second in space
without a helmet. The movie made it appear that the major problem was lack
of oxygen, and if Dave held his breath long enough, he would survive. I am
not buying that one. As soon as he was exposed to the lack of pressure, his
head and such would explode. Anyway, proving this (either way) is left as
an exercise for the reader.
--
-----------------------------------------------------------
Mike Tighe, Internet: ti...@convex.com
Voice: (214) 497-4206 Fax: (214) 497-4550
-----------------------------------------------------------
Charlie Gibbs
>As fate would have it, the public TV station here (KTCA) showed 2001 a few
days
>ago. Over a few beers, I took notes. (naah, I didn't have too many, the
notes
>are still readable at the end :-))
Yup, pretty well matches up with my memories. I haven't seen
2001 for a long time (I could never bring myself to watch it on the
small screen) but it sure blew me away when it came out.
>Roughly chronologically through the movie, you see things like:
>
>"IBM" on the earth-to-station shuttle consoles (for the pilot and co-pilot).
>This is the first scene with a 'computer' in it - follows the 20-minute or
>so famous 'monkey' intro scenes.
Speaking of trade marks (I wonder how many bucks those were worth)
the shuttle was Pan Am, and the space station contained a Hilton as
well as Howard Johnson's Earthlight Room.
>The ten-second scene with the 'zero-gravity' toilet is a classic. Wonder
>what microprocessors are used here. Can't you see the marketing guys saying,
>'yeah, our micros are used in the space station toilets!!'
I always wondered what those detailed instructions for the zero-G
toilets read. In the book "The Making of Kubrick's 2001" they are
reprinted in full. I could look up author, ISBN, etc. if anyone is
interested.
>The earth-to-moon shuttle gives the first glimpse of the 3-D navigation
>consoles. Also, this is where one first sees the three-letter acronyms
>appear on the consoles. 'COM' and 'NAV' appear. Communications and
>navigation?
>(note, the others that appear through the film are ODE, LIF, MEM, NUC, ATM,
>DMG, VEH, FLX, and CNT. Any guesses?)
Here are my guesses:
COM - communications
NAV - navigation
LIF - life support
MEM - computer memory
NUC - nuclear (propulsion and/or power)
ATM - atmosphere (air supply, possibly heating/cooling as well)
DMG - damage control
VEH - vehicle status
I may have seen HIB (hibernation control?) as well.
The displays were pretty spiffy.
>Moving through the film, I was taken by Clarke's brilliance on describing
>conflict (computer versus man), how man is so dependent on computers, yet
>how so ingenious man is, compared to computers (like when Dave figures out
>a way to get in after HAL won't open the pod bay doors). Could a computer
>have figured out a way to get in? Foreshadowing of the massive problems
>and challenges of AI?
Actually, HAL knew about the emergency air lock, but had
dismissed it as unusable ("Without your space helmet, I'm afraid
that would be rather difficult" if I remember the quote correctly).
Incidentally, Dave's successful entry was consistent with ongoing
discussions as to how long a person could survive in a vacuum.
(I bet his ears hurt, though. :-)
>operational at (what sounds like on the film) 'HAL-land', in Urbana,
I always thought he said "at the H.A.L. lab". BTW I once heard
an album of early sound synthesis made by an IBM 7090 (or was it 7094?)
hooked to a "digital to sound transducer" (presumably just a D-to-A
converter). It did a nice intrumental rendition of "A Bicycle Built
for Two," but I almost fell out of my chair laughing when it sang
recognizable words to the song. Presumably this predates 2001 (it
sounds like Kubrick's sense of humour) - can anyone confirm this?
I thought it was good to see the movie first, then read the book
and find out just what the hell happened at the end. Great special
effects (indeed they set the standard for many years) but I always
thought there was more to it than just "Wow, look at the neat lights,
man!"
Kubrick's choice of music was also exceptional. I'll never
forget the first scenes of Discovery heading out towards Jupiter -
the music gave such a sense of distance and isolation. The Blue
Danube can never again be just a cheap little tune that everyone
whistles, but instead a part of the incredible beauty of those
scenes in orbit and approaching the Moon. I try to ignore the
way Also Sprach Zarathustra has been ground into the dirt by just
about everyone - it's still a powerful piece of music in its own
right. (BTW what you hear in the movie is just the introduction -
the full piece takes up a whole album and is pretty good if you
don't mind heavy German classical music.)
Charli...@mindlink.UUCP
Elevator music brings me down.
Tom Neff
>I think HAL wins on the air lock scene. Sure, Hollywood made Dave look
>smarter than HAL, but I do not believe you would last one second in space
>without a helmet. The movie made it appear that the major problem was lack
>of oxygen, and if Dave held his breath long enough, he would survive. I am
>not buying that one. As soon as he was exposed to the lack of pressure, his
>head and such would explode. Anyway, proving this (either way) is left as
>an exercise for the reader.
But suffering through the above "explanation" is retained as an exercise
for the Altnet readership. ;-)
Fourteen PSI is not enough to rupture flesh, skin or bone. "Exploding"
in vacuum is a long-ago "exploded" myth. (A good entry for the urban
legends FAQ list, come to think of it.) It's a pity they don't put
errata sheets in all those 30 year old SF paperback reprints kids read.
Any air or other gas in your lungs, mouth, nose, trachea, esophagus,
colon (eugghh) and so forth would outgas immediately. "Holding your
breath" could get you hurt. The pressure differential on your eardrums
could cause rupture if you weren't careful to pop your Eustachian tubes
by swallowing or jaw clenching. With practice you ought to be able to
close the trachea after most of the air is expelled, keeping a PSI or
two in your lungs to prevent alveoli damage. Any exposed liquid
surfaces, such as mucous membranes, would start to boil or evaporate.
Eyes closed would probably be mandatory to avoid damage. On the other
hand, if you're Dave Bowman and this is your only chance to live, you
might well break a few safety rules. :-)
I thought the emergency airlock sequence was terrific, just one of the
reasons 2001 holds up so marvelously almost twenty-five years later.
Mike Tighe
>In article <1991Mar06.2...@convex.com> ti...@convex.com (Mike Tighe) writes:
>>I think HAL wins on the air lock scene. Sure, Hollywood made Dave look
>>smarter than HAL, but I do not believe you would last one second in space
>>without a helmet. The movie made it appear that the major problem was lack
>>of oxygen, and if Dave held his breath long enough, he would survive. I am
>>not buying that one. As soon as he was exposed to the lack of pressure, his
>>head and such would explode. Anyway, proving this (either way) is left as
>>an exercise for the reader.
>But suffering through the above "explanation" is retained as an exercise
>for the Altnet readership. ;-)
>Fourteen PSI is not enough to rupture flesh, skin or bone. "Exploding"
>in vacuum is a long-ago "exploded" myth. (A good entry for the urban
>legends FAQ list, come to think of it.) It's a pity they don't put
>errata sheets in all those 30 year old SF paperback reprints kids read.
OK. So explode was a bad word choice. I didn't mean for it to sound like he
had a hand grenade in his mouth. And since he had no other options to
choose from, it wasn't all that unreasonable a choice. But I think he
certainly would have died, and that was my point.
Joel Kolstad
>>I think HAL wins on the air lock scene. Sure, Hollywood made Dave look
>>smarter than HAL, but I do not believe you would last one second in space
>>without a helmet. The movie made it appear that the major problem was lack
>>of oxygen, and if Dave held his breath long enough, he would survive. I am
>>not buying that one. As soon as he was exposed to the lack of pressure, his
>>head and such would explode. Anyway, proving this (either way) is left as
>>an exercise for the reader.
>
>But suffering through the above "explanation" is retained as an exercise
>for the Altnet readership. ;-)
>
OK, forgive my ignorance, but I've got a question relating to this...
In "Deep Star Six," (movie about a bunch of researchers trapped with a horrible
monster at the bottom of the sea...), one guy goes a little crazy and takes
an "escape pod" up to the surface without depressurizing.
In true Hollywood style, as the guy goes up, up and away, we see his ears
bleeding, then his nose bleeding, his eyes bulging, and right before the
camera cuts to the wall of the escape pod, we see a jet of blood shooting
from his hand. The next things we see is an bloody explosion on the escape
pod wall.
Pure fiction, right?
Down at the bottom of the sea in a "research station," the pressure could
conceivably be greater than 1ATM, but merely going from, say, even 2ATM to
1ATM fairly rapidly (or, for that matter, going from xATM (x>1) to 1ATM ???)
shouldn't cause harm, right?
I do realize that the guy _would_ probably die from the bends as he'd be
unable to get enough oxygen into his blood from nitrogen displacement.
Could someone who knows tell me if this explanation is correct? Thanks.
---Joel Kolstad
kol...@jomby.cs.wisc.edu
Sorry this has nothing to do with computers. :-)
Tony Lezard
> I think HAL wins on the air lock scene. Sure, Hollywood made Dave look
> smarter than HAL, but I do not believe you would last one second in space
> without a helmet. The movie made it appear that the major problem was lack
> of oxygen, and if Dave held his breath long enough, he would survive. I am
> not buying that one. As soon as he was exposed to the lack of pressure, his
> head and such would explode. Anyway, proving this (either way) is left as
> an exercise for the reader.
I'm afraid you lose on the airlock scene :-) . The pressures in the body
are not sufficient to cause the body to explode, least of all his skull.
In fact, this scene was deliberately put in in order to 'explode' (!) the
myth. This is veering towards alt.folklore.urban and sci.misc now so I'll
leave it there.
--
Tony Lezard <Lazy Rodent>. E-mail: to...@mantis.co.uk, Snail: Mantis
Consultants, Unit 56, St. John's Innovation Centre, Cambridge, CB4 4WS, UK.
"I thoroughly enjoyed the food. And learnt quite a lot about fetal
deformities." -- sj...@eng.cam.ac.uk (Stephen Mounsey)
Otto J. Makela
[re David Bowman jumping vacuum in 2001]
OK. So explode was a bad word choice. I didn't mean for it to sound like
he had a hand grenade in his mouth. And since he had no other options to
choose from, it wasn't all that unreasonable a choice. But I think he
certainly would have died, and that was my point.
I spoke about this last summer with an old NASA engineer. He told me that
basically the film scene was right, except that he should have blacked out
for a few seconds about seven seconds after his lungs had no oxygen intake
(of course, you can imagine this happening as the scene does not show him
leaving the airlock).
Seems it takes this long for the non-oxygen-bearing blood to reach the
brain from the lungs. Other decompression effects include the swelling
of all loose bits of skin (joints, specially the ankles and thumb/index
finger connection) making it hard to stand up or grasp things. However,
it takes several minutes for irreversible damage to take place.
As this has little to do with computer folklore anymore,
I'm followuping this to sci.space !
--
/* * * Otto J. Makela <ot...@jyu.fi> * * * * * * * * * * * * * * * * * * */
/* Phone: +358 41 613 847, BBS: +358 41 211 562 (USR HST/V.32, 24h/d) */
/* Mail: Kauppakatu 1 B 18, SF-40100 Jyvaskyla, Finland, EUROPE */
/* * * Computers Rule 01001111 01001011 * * * * * * * * * * * * * * * * */
Tom Gardner
|smarter than HAL, but I do not believe you would last one second in space
|without a helmet. The movie made it appear that the major problem was lack
|of oxygen, and if Dave held his breath long enough, he would survive. I am
|not buying that one. As soon as he was exposed to the lack of pressure, his
|head and such would explode. Anyway, proving this (either way) is left as
|an exercise for the reader.
1) what does Hollywood have to do with it?
2) yes, you can survive in a vacuum for a short time. The skin is remarkably
good at keeping your insides in.
3) the major problems would be with surface water flashing to vapour, thus
cooling exposed surfaces (particularly eyeballs), and decompression of the
lungs (for which it is best to expel any air in the lungs: ask any diver).
4) Experiments on animals have verified that brief exposure to vacuum is
possible.
Jonathan Griffitts
Regarding the scene in 2001 where the astronauts retest the failed
AE-35 unit:
I realized that my perspectives had changed after working with board
test systems (called ATE for Automatic Test Equipment) for a couple of
years.
When I saw that scene again, I thought "OK, the board was flakey in
the system but passed ATE."
Nothing alarming or unusual about that!
--
--JCG
AnyWare Engineering, Boulder CO
303 442-0556
mathew
> I think HAL wins on the air lock scene. Sure, Hollywood made Dave look
> smarter than HAL, but I do not believe you would last one second in space
> without a helmet. The movie made it appear that the major problem was lack
> of oxygen, and if Dave held his breath long enough, he would survive. I am
> not buying that one. As soon as he was exposed to the lack of pressure, his
> head and such would explode.
So, what do the collected intelligences in alt.folklore.urban reckon?
We have the commonly-held belief:
People explode when exposed to the vacuum of space.
What's the verdict? Anyone know of any proper medical studies or anything?
mathew
Steve Simmons
>In "Deep Star Six," (movie about a bunch of researchers trapped with a horrible
>monster at the bottom of the sea...), one guy goes a little crazy and takes
>an "escape pod" up to the surface without depressurizing.
>In true Hollywood style, as the guy goes up, up and away, we see his ears
>bleeding, then his nose bleeding, his eyes bulging, and right before the
>camera cuts to the wall of the escape pod, we see a jet of blood shooting
>from his hand. The next things we see is an bloody explosion on the escape
>pod wall.
>Pure fiction, right?
>Down at the bottom of the sea in a "research station," the pressure could
>conceivably be greater than 1ATM, but merely going from, say, even 2ATM to
>1ATM fairly rapidly (or, for that matter, going from xATM (x>1) to 1ATM ???)
>shouldn't cause harm, right?
Deep diving creates fantastic pressures very quickly. I don't recall
the number off the top of my head, but it takes relatively few (12?
16?) feet of water to equal one atmosphere. "Deep Star 6" involved
folks who were *thousands* of feet down, probably under several hundred
atmospheres. 14psi ain't much, but 1400?
When deep-sea fishing I'd occasionally hook some fishie 60-100 feet
down and reel him up fast. No explosion, but pretty disgusting --
gills distended, fish in obvious distress. Now multiply that by 100
and assume the creature has air-filled lungs and sinuses.
--
"Perl is the BASIC of UNIX." -- Tom Christiansen
Ian Farquhar
article to all those who requested it. If I've missed anyone, send me
another email message and I will send another copy.
By the number of responses I got, there are going to be a lot of funny
things printed on laser printer LCD panels real soon now... :-)
--
Ian Farquhar Phone : + 61 2 805-9400
Office of Computing Services Fax : + 61 2 805-7433
Macquarie University NSW 2109 Also : + 61 2 805-7420
Australia EMail : ifar...@suna.mqcc.mq.oz.au
Anthony J Stieber
>OK. So explode was a bad word choice. I didn't mean for it to sound like he
>had a hand grenade in his mouth. And since he had no other options to
>choose from, it wasn't all that unreasonable a choice. But I think he
>certainly would have died, and that was my point.
Here are some postings from Sci.med a few months ago.
From: g...@client2.DRETOR.UUCP (Thomas Gee )
Newsgroups: sci.med
Subject: Re: A human being in vacuum
Message-ID: <38...@client2.DRETOR.UUCP>
Date: 11 Dec 90 15:16:25 GMT
References: <347.27...@nphi.fi>
Organization: Defence and Civil Institute of Environmental Medicine
Lines: 46
In article <347.27...@nphi.fi> tro...@nphi.fi writes:
>
>Medical experts aren't needed. Physics will suffice. The operative term is
>"flash boil."
>
>(Edifying experiment: evacuate the air from a jar partially filled with liquid
>water.)
>--
>* Daniel R. Levy * uunet!tellab5!mtcchi!levy * |
>* These views are live; they are not Memorex' * --+--
>Praise the Lord, Praise the Lord, let the earth hear His voice; |
>Praise the Lord, Praise the Lord, let the people rejoice. [F. Crosby] |
Physics tends to become a bit complicated when you're working with something
as complex as a human body.
I presume when you write (type?) "flash boil", you are speaking of explosive
decompression. It is my understanding that explosive decompression is
a concern if you have some lungs filled with air, for this could cause dangerous
ruptures, but if the lungs are evacuated first, the human body shows remarkable
endurance under low pressure conditions.
Here at DCIEM we have done studies of explosive decompressions, although not
exposing people to raw vacuum (pretty difficult stuff to generate on the
surface of this planet). Our studies have taken people from 10,000 feet to
80,000 feet in roughly 0.3 seconds. The greatest difficulty with such exposures
is the formation of water vapour in the lungs, but this can be countered by
repressurizing the air in the lungs (positive-pressure breathing).
One interesting sidelight of these experiments is that, since the boiling
point of a liquid is a function of ambient pressure, at these altitudes water
boils at less than body temperature. No, this doesn't result in your blood
percolating in your brain, since blood is itself is under considerable pressure.
However, water escapes quite happily from your skin (strange sensation I'm
told), and your eyes tear unmercifully. The tears boil off immediately,
leaving you with rather chilly eyeballs.
(BTW: I'm not a physiologist, just a simple-minded software developer,
so caveat emptor.)
-------------------------------------------------------------------------------
Thomas Gee |
Aerospace Group | a man in search of a quote
DCIEM, DND |
Canada | g...@dretor.dciem.dnd.ca
-------------------------------------------------------------------------------
From: g...@client2.DRETOR.UUCP (Thomas Gee )
Newsgroups: sci.med
Subject: Re: A human being in vacuum
Message-ID: <38...@client2.DRETOR.UUCP>
Date: 12 Dec 90 14:45:24 GMT
References: <1990Dec7.2...@mtcchi.uucp> <95...@pasteur.Berkeley.EDU>
Organization: Defence and Civil Institute of Environmental Medicine
Lines: 42
In article <95...@pasteur.Berkeley.EDU> shir...@sprite.berkeley.edu (Ken Shirriff) writes:
>In article <347.27...@nphi.fi> tro...@nphi.fi writes:
>>>>how long could a human being possibly survive unprotected in the raw
>>>>vacuum of space?
>
>The body will start to swell after 30 seconds. Two minutes at pressure
> below 30mm Hg is fatal,
Hmm, I doubt this fact rather greatly. In the late 70's, DCIEM did a number
of runs where people were regularly exposed (explosively) to 80,000 foot
altitudes for up to four minutes. Oxygen was supplied at high pressure, so
anoxia wasn't a problem. Although there is distension, it is most assuredly
not fatal (ethics boards tend to frown on fatal experiments). I'm not
certain of the atmospheric pressure at 80,000, but I know that at 60,000 it
is 54 mmHg, so 80,000 should be within spitting distance of 30mmHg.
>Explosive decompression to 65000 feet is tolerable with no injury if
>followed by immediate recompression.
Better yet, to 80,000 feet, as above. There is evidence that we can go higher,
but we do tend to run into the bends problems.
>This information is from "Space Medicine", by Ursula T. Slager. It
>has other interesting facts such as that an unprotected human survived
>482 deg F for 4 minutes, and humans can survive 100G for 1/4 second.
Actually, G tolerance is inversely proportional to exposure time, because of
the body's inertia. So you can stand infinite G for an infinitely short
amount of time. We've exposed people only up to 15G for a short burst
(impact sled), and had people experience 9G for several 15s episodes.
>
>Ken Shirriff shir...@sprite.Berkeley.EDU
Caveat: as before, I'm only the software developer, not a physiologist.
-------------------------------------------------------------------------------
Thomas Gee |
Aerospace Group | a man in search of a quote
DCIEM, DND |
Canada | g...@dretor.dciem.dnd.ca
-------------------------------------------------------------------------------
From: shir...@sprite.berkeley.edu (Ken Shirriff)
Newsgroups: sci.med
Subject: Re: A human being in vacuum
Message-ID: <97...@pasteur.Berkeley.EDU>
Date: 14 Dec 90 18:32:09 GMT
References: <1990Dec7.2...@mtcchi.uucp> <95...@pasteur.Berkeley.EDU> <38...@client2.DRETOR.UUCP>
Sender: ne...@pasteur.Berkeley.EDU
Organization: University of California, Berkeley
Lines: 64
In article <38...@client2.DRETOR.UUCP> g...@client2.DRETOR.UUCP (Thomas Gee ) writes:
>In article <95...@pasteur.Berkeley.EDU> shir...@sprite.berkeley.edu (Ken Shirriff) writes:
>>The body will start to swell after 30 seconds. Two minutes at pressure
>> below 30mm Hg is fatal,
>Hmm, I doubt this fact rather greatly. In the late 70's, DCIEM did a number
>of runs where people were regularly exposed (explosively) to 80,000 foot
>altitudes for up to four minutes. Oxygen was supplied at high pressure, so
>anoxia wasn't a problem.
Rereading my reference, they did the study on "warm blooded animals",
and they didn't have any oxygen. This probably accounts for the difference.
Here are various other fun facts:
Altitude/Time of useful consciousness/Time to unconsciousness
25000ft 120-180s 420-240s
35000 45-60 60
50000+ 15 15
These values are improved by acclimatization: in one study, unacclimatized
people remained conscious 1-2 min at 30000ft; acclimatized people 2-30 min,
and Peruvian natives (living at 14,900ft) remained conscious for an hour.
Pure unpressurized oxygen at 34000ft has oxygen equivalent altitude of
sea level (i.e. it's equivalent to breathing sea level air).
Unpressurized oxygen at 50000ft has o.e.a. of 50000ft (i.e. it's useless).
Pressurized oxygen at 60000ft has o.e.a. of 26000ft, but is very fatiguing
since the respiratory muscles must work against the pressure gradient.
In explosive decompression, with an unobstructed airway the lung damage
is slight. With obstruction (e.g. holding your breath), pneumomediastinum,
emphysema of the soft tissues around the pulmonary vessels, and aeroembolism
in the hart, coronary, and cerebral arteries may be seen. With unobstructed
airways, the main damage appears due to anoxia.
To convert altitude to pressure, here's the US standard atmosphere:
0 ft 760.0 mmHg 59 deg F
10000 522.6 23.3
20000 349.1 -12.3
30000 225.6 -48
40000 140.7 -67
50000 87.3 -67
60000 54.15 -67
70000 33.6
80000 20.8
90000 12.9
10000 8.0
150000 1.08
200000 0.24
300000 0.0055
And my favorite quote:
"Man cannot survive without both a minimum total atmospheric pressure and
a minimum partial pressure of oxygen. If either is deficient, he develops
certain abnormal responses which may culminate in death."
An unrelated fun pet trick:
"Guppies can tolerate 10000G for 30 sec."
The above information is all from "Space Medicine". I personally don't
know anything about the subject. Remember, you can learn way more by
skimming through a book than from reading a net posting.
Ken Shirriff shir...@sprite.Berkeley.EDU
From uwm.edu!caen!sdd.hp.com!hplabs!hpfcso!ron Mon Dec 17 23:23:50 CST 1990
Article: 22893 of sci.med
Path: uwm.edu!caen!sdd.hp.com!hplabs!hpfcso!ron
From: r...@hpfcso.HP.COM (Ron Miller)
Newsgroups: sci.med
Subject: Re: Air pressure questions (A human being in vacume)
Message-ID: <754...@hpfcso.HP.COM>
Date: 12 Dec 90 20:24:01 GMT
References: <1990Dec11.1...@unicorn.cc.wwu.edu>
Organization: Hewlett-Packard, Fort Collins, CO, USA
Lines: 98
You have two conditions:
1. Transient responses. Things like embolism and bends come from
this.
2. Steady state. Steady state is "how high can man function.?"
> 1) Imagine a cabin door breaks, something causes the pressure to
> go way down. Would it be better to try to hold your breath,
> or could that just cause more damage.
Transient situation.
If you hold your breath, the air in your lungs will expand and rupture
the fragile tissue. This is called an "embolism (sp?)" . It can kill
you. It's one of the thing scuba divers must learn about for rates
of rising to the surface. It also was why in the submarine
escape trainer, when doing a 100' free ascent one is required
to "ho ho ho" all the way to the surface to absolutely ensure you
are breathing OUT.
>
> 2) If someone suddenly was exposed to 1/2 s.l. pressure
> What harm would be possible right away? What about gradualy
> (over a few minutes or hours), like if he had extra oxygen?
>
> 2.1) How about 1/4 or 1/8 ... or 1/32 etc.
Transient.
Bends, dissolved gases in the blood coming out of solution. It used to
be thought that the major problem was bubbles in joints. Now a new
symptom has been documented - air bubbles in the blood vessels
of the retina. Can you say, "... leading to blindness gradually, perhaps"
Also, the body needs time to adapt to the new partial pressure of
oxygen as best it can and for small transients, you will remain
conscious. For larger transients, you will pass out within a
couple of minutes. (I don't know the specifics.) Airliners
are required to have the pilot capable of donning and breathing
100% oxygen within 1 minute in the event of a cabin depressurization.
Someone needs to be able to fly the plane to lower altitudes.
>
> 2.2) What is the highest alt/lowest p. that people live at?
Steady State
About 17,000 MSL in Tibet.
Transient
But climbers have climbed Everest w/o O2. (28,000') They are
risking: pulmonary edema, cerebral edema, blood clots, and mistakes
from malfunctioning brains.
> Is it the pressure that limits them, or just cold and inaccesablility,
> no food, etc, that keeps them from going higher?
Probably a lot of things. Health is jeopardized by low O2. See mountain
climbing texts. Food cannot be metabolized, blood chemistry changes etc.
>
> 3) If a person was breathing pure oxygen at 1/5 normal pressure,
> What do you think would happen? What might be harmfull about it,
> under what conditions might it be safe?
> (-not inside a plane. imagine there's just some _place_ like that
> where people could go)
Steady State
100% O2 provides sufficient partial pressure for humans to operate
at about 30,000'. Partial pressures of 100-120 mbar is "normal"
Smokers flake out much lower due to lung function impairment.
Steady State.
Humans don't care about percentages, their phsyiology cares about partial
pressure of oxygen. Too high a partial pressure and you get oxygen
poisoning (that's why divers don't use 100% O2 any deeper than
about 20'). Too low a partial pressure and you'll pass out.
This fact is what allows super deep diving in the ocean.
Mix 1% O2 with 99% Helium and a human can breathe it perfectly well
at the depth where the pp is right. On the surface, if you breathe this,
you'll suffocate.[ N2 is not used in the mix because at high partial
pressures, N2 causes "nitrogen narcosis" which is very like being
drunk. This is the practical factor limiting compressed air dives
much below 120'. See diving texts. (Imagine offering your mouthpiece
to a fish, for example!) ]
One problem with altitude and space, is that 100% O2 won't have enough
pressure by itself to cross the lung tissue at very high altitudes/low
pressures. That's what pressure suits are for.
My qualifications: Flight Instructor (aviation info)
Scuba Diver (in college, water info)
Nuclear Submariner (atmosphere control officer, water escape
physiology)
Student of Mountain Climbing (I climb 14,000' mountains
in Colo. Even that is enough to get altitude effects.)
Ron Miller
--
<-:(= Anthony Stieber ant...@csd4.csd.uwm.edu uwm!uwmcsd4!anthony
The Polymath
}smarter than HAL, but I do not believe you would last one second in space
}without a helmet. The movie made it appear that the major problem was lack
}of oxygen, and if Dave held his breath long enough, he would survive. I am
}not buying that one. As soon as he was exposed to the lack of pressure, his
}head and such would explode. Anyway, proving this (either way) is left as
}an exercise for the reader.
This was discussed at some length in sci.med last year. The critical
factors are pressure differential and speed of decompression.
If Dave had gone to pure O2 and lowered his cabin pressure to minimum
breathable pressure, then hyperventilated just before he blew the door, he
probably would have survived with few or no ill effects.
As I recall, the movie skipped over those details. They skipped a lot of
other details, too. Hollyweird in action.
--
The Polymath (aka: Jerry Hollombe, M.A., CDP, aka: holl...@ttidca.tti.com)
Head Robot Wrangler at Citicorp Illegitimis non
3100 Ocean Park Blvd. (213) 450-9111, x2483 Carborundum
Santa Monica, CA 90405 {rutgers|pyramid|philabs|psivax}!ttidca!hollombe
young a t
>hooked to a "digital to sound transducer" (presumably just a D-to-A
>converter). It did a nice intrumental rendition of "A Bicycle Built
>for Two," but I almost fell out of my chair laughing when it sang
>recognizable words to the song. Presumably this predates 2001 (it
>sounds like Kubrick's sense of humour) - can anyone confirm this?
Yes, as I recall the record was made at BTL. Carl Sagan was much taken with it
and I believe was the person who suggested to Kubrick that he use it.
A.T.Young (a...@mintaka.sdsu.edu)
Robert Murphy
>I think HAL wins on the air lock scene. Sure, Hollywood made Dave look
>smarter than HAL, but I do not believe you would last one second in space
>without a helmet. The movie made it appear that the major problem was lack
>of oxygen, and if Dave held his breath long enough, he would survive. I am
>not buying that one. As soon as he was exposed to the lack of pressure, his
>head and such would explode. Anyway, proving this (either way) is left as
>an exercise for the reader.
Back in my salad days as a chemist, on one of those late nights in the lab
watching a reaction to make sure it didn't go haywire, I decided to test the
resistance of cockroaches to vacuum. I took one of the local Texas water
bugs and forced it to submit to increasing indignities, culminating in
two hours at .005 torr. Considering that atmospheric pressure is roughly
760 torr, well, it wasn't quite outer space, but it was so close as to
make no difference.
How did the cockroach do? Well, after about ten minutes, it started wiggling
its antennae, and after about a half-hour, it seeemed okay. Mind you,
cockroaches can't really hold their breath; they breathe through holes in
their chitin exterior called spiracles, which have nothing like sphincter
muscles.
I would say that if a cockroach could survive such vacuum for two hours
*without* holding its breath, it's quite possible a human could survive
it for a couple of minutes while holding his breath.
Bob Murphy
bob...@autodesk.com
Il Oh
[decription of torturing a cockroach in near-vacuum deleted]
>How did the cockroach do? Well, after about ten minutes, it started wiggling
>its antennae, and after about a half-hour, it seeemed okay. Mind you,
>cockroaches can't really hold their breath; they breathe through holes in
>their chitin exterior called spiracles, which have nothing like sphincter
>muscles.
Wow! I guess it's true what they say. If blow ourselves up (not too likely
any more), I guess it WILL be the cockroaches that dominate.
--
"I'm sorry. | Il Hwan Oh
If you were right, | University of Washington, Tacoma
I would agree with you." | i...@cac.washington.edu
-- Dr. Malcolm Sayer, _Awakenings_ |
The Polymath
[ I won't even try to sort out the attributions ... ]
}>Medical experts aren't needed. Physics will suffice. The operative term is
}>"flash boil."
}>
}>(Edifying experiment: evacuate the air from a jar partially filled with liquid
}>water.)
As it happens I saw said experiment performed just a couple of weeks ago.
The water freezes. To be more precise, surface evaporation takes place
until all the high energy molecules are gone. This doesn't take very long
at room temperature, so most of the water is left to freeze.
For a more interesting experiment, fill a 2" diameter pipe by immersing it
in water and sealing the ends. Now immerse it in liquid N2 and run like
hell. (Kids, don't try this at home!) (-:{
David E A Wilson
>For a more interesting experiment, fill a 2" diameter pipe by immersing it
>in water and sealing the ends. Now immerse it in liquid N2 and run like
>hell. (Kids, don't try this at home!) (-:{
I saw an interesting variation on this theme on TV last night. It concerned
a Swede who has an ice powered go-kart. He has a large gas bottle with 90%
water and 10% hydraulic oil in it connected to an accumulator on the kart.
You leave it outside overnight in the winter. The water freezes, expands
compressing the oil which is then used to power the kart.
--
David Wilson Dept Comp Sci, Uni of Wollongong da...@cs.uow.edu.au
Don Stokes
> I would say that if a cockroach could survive such vacuum for two hours
> *without* holding its breath, it's quite possible a human could survive
> it for a couple of minutes while holding his breath.
Sorry Bob, not a valid test. Cockroaches will survive anything.
A favourite experiment in this country is to freeze wetas in ice for a
couple of months, then let them out.... (a weta is a spiny brown solidly
built grasshopper-like insect, the common ones being about two or more
inches from nose to tail (excluding legs, long antennae & vicious
looking ovipositor on the females); rare models are *much* bigger...)
(an invalid test doesn't invalidate the conclusion -- Dave Bowman
*could* have done the job, but not because a cockroach can...)
Don Stokes, ZL2TNM / / d...@zl2tnm.gp.co.nz (home)
Systems Programmer /GP/ GP PRINT LIMITED Wellington, d...@gp.co.nz (work)
__________________/ / ---------------- New_Zealand__________________________
Robert Murphy
>Sorry Bob, not a valid test. Cockroaches will survive anything.
>
>A favourite experiment in this country is to freeze wetas in ice for a
>couple of months, then let them out.... (a weta is a spiny brown solidly
>built grasshopper-like insect, the common ones being about two or more
>inches from nose to tail (excluding legs, long antennae & vicious
>looking ovipositor on the females); rare models are *much* bigger...)
Okay, you made me do it! I didn't want to, but now I have to tell about
all the gruesome things I did to kill cockroaches in the chemistry lab.
All this, just to disprove your contention that "cockroaches will survive
anything."
Well, maybe I did want to tell about it...
Anyway, here are some activities guaranteed to kill cockroaches:
1. Drop them in liquid nitrogen. (They stay in good shape, and are
convenient for putting on peoples desks, in their mailboxes, etc.)
2. Make them dance on dry ice in a Dewar flask.
3. Drop them in concentrated sulfuric acid.
4. Drop them in boiling sodium hydroxide solution. (This process, known as
saponification, is used to create soap from animal fat or plant oils.
It works on roaches, too. You get nice foamy roach soap at the top.)
5. Hold them in a bunsen burner flame with a pair of tongs. (Smells awful.)
6. Put them in a flask with thionyl chloride. (Terminal chlorination
reaction.)
7. Make them breathe diethyl ether. Yes, the one that's an anesthetic for
humans. On the flip side, acetone vapors are an anesthetic for roaches,
but kill humans.
A related activity:
The exoskeleton of cockroaches, like all arthropods, is a polysaccharide
akin to starch called "chitin". Chitin is soluble in a common laboratory
solvent called "dichloromethane" or "methylene chloride". (This solvent is
somewhat toxic to the liver, so don't use it without adequate ventilation.)
Dichloromethane also has a boiling point of about 37 degrees C, which is
not too far above room temperature, so it evaporates pretty quickly.
The stupid roach trick is to find a big "water bug" (the one-two inch
variety with wings), and kick it around on a tile floor with soccer kicks
until it winds up on its back. Put a small (1-2 inch) puddle of dichloro-
methane on the floor next to it, and shove the roach into it so that its
back is in the middle of the puddle. This will dissolve part of its wings.
In a minute or so, the solvent will evaporate, the dissolved chitin will
solidify into a kind of glue, and you now have a live cockroach with its
back welded to the floor, madly wiggling its legs. This is very upsetting
to most janitors.
We really should move this thread to sci.chem or alt.pyrotechnics or
alt.national.enquirer... but it's too much fun.
Bob Murphy
bob...@autodesk.com
Ron Harding
>Well, maybe I did want to tell about it...
>
>Anyway, here are some activities guaranteed to kill cockroaches:
>1. Drop them in liquid nitrogen. (They stay in good shape, and are
> convenient for putting on peoples desks, in their mailboxes, etc.)
>2. Make them dance on dry ice in a Dewar flask.
>3. Drop them in concentrated sulfuric acid.
>4. Drop them in boiling sodium hydroxide solution. (This process, known as
> saponification, is used to create soap from animal fat or plant oils.
> It works on roaches, too. You get nice foamy roach soap at the top.)
>5. Hold them in a bunsen burner flame with a pair of tongs. (Smells awful.)
>6. Put them in a flask with thionyl chloride. (Terminal chlorination
> reaction.)
>7. Make them breathe diethyl ether. Yes, the one that's an anesthetic for
> humans. On the flip side, acetone vapors are an anesthetic for roaches,
> but kill humans.
>until it winds up on its back. Put a small (1-2 inch) puddle of dichloro-
>methane on the floor next to it, and shove the roach into it so that its
>solidify into a kind of glue, and you now have a live cockroach with its
>back welded to the floor, madly wiggling its legs. This is very upsetting
>to most janitors.
>
>bob...@autodesk.com
Well, that was... umm... interesting. I'll have to remember those
tricks.
(We're dealing with one sick puppy here, folks!)
=============================================================================
"Nuke'Em:" Get them before they get you. | Ron Harding
Another quality home game from Butler Bros. | (rbha...@rose.uwaterloo.ca)
=============================================================================
Jon Buck
>Down at the bottom of the sea in a "research station," the pressure could
>conceivably be greater than 1ATM, but merely going from, say, even 2ATM to
>1ATM fairly rapidly (or, for that matter, going from xATM (x>1) to 1ATM ???)
>shouldn't cause harm, right?
Yes, it will. I seriously doubt that it would be very graphic as far as
blood and gore is concerned, but if your bloodstream is nitrogen-saturated
at your starting depth, you can die of the bends even going from 30 feet to
the surface. Coming up from extreme depths very rapidly with no
decompression would probably send a large bubble of air to your heart and
kill you pretty much instantaneously. Of course, if the research station
were at 1 ATM, there would be no such effects.
>Deep diving creates fantastic pressures very quickly. I don't recall
>the number off the top of my head, but it takes relatively few (12?
>16?) feet of water to equal one atmosphere. "Deep Star 6" involved
>folks who were *thousands* of feet down, probably under several hundred
>atmospheres. 14psi ain't much, but 1400?
Pressure increases by 1 ATM for every ~33 feet of water depth, ie.
33 feet = 2 ATM, 66 feet = 3 ATM, and so on.
Further discussion should be moved to rec.scuba, unless we want to talk
about dive computers :-).