HDTenEightyP/NetNews huggingface dataset:
From: doug@wente.llnl.gov (Douglas S. Miller)
Newsgroups: sci.physics
Subject: Re: High-Pressure Gas Tanks--How Many PSI?
Date: 13 Nov 92 22:42:39 GMT
Organization: UC Davis Dept of Applied Science at LLNL

01crmeyer@leo.bsuvc.bsu.edu (Craig Meyer) writes:
>I'm looking into the concept of running an automobile off of compressed air.
>According to my calculations (based on a Gast airmotor catalogue), such a 
>vehicle would need air tanks that could hold 100,000 psi.
>Is that at all possible?

I'll take a shot at this for fun, but be aware that I am *not* a
materials person.  The short answer is no, it isn't possible. Or rather, 
yes it is but it isn't a good way to make a speedy automobile.  (This is 
of course my ignorant opinion--I could be wrong.)

From my scuba diving days we know that a steel cylinder will hold about 
2500 psi, and such a cylinder weighs in at about 20 lbs (there ought to be 
some more current divers who can give us the exact weight of a tank).  Now 
you want to put in 100,000 psi, a factor of 40 increase in pressure.  It 
seems reasonable that a factor 40 increase in the wall thickness is needed 
to compensate.  The weight of the tank, however, will go roughly as wall 
thickness squared (mass = density*pi*(r_outer^2-r_inner^2)*height), so now 
we're talking a 40*40*(20 lbs) = 3200 lb tank.  This sucker will also be big; 
tank walls in scuba are at least an inch thick if memory serves and 
we're going to increase that by 40. This gives us a tank about seven feet 
in diameter at a bare minimum.

Now all this assumes that we're scaling up a scuba tank to fit your
application.  There may be better designs (spheres maybe) that will
make 100,000 psi practical.  I'm sure there are high pressure
experimentalist types out there who can give a real answer.

Doug Miller	doug@retzlaff.llnl.gov
"But *why* can't I use a gas station air pump on my bike tire?"
Newsgroups: sci.physics
From: jbaez@riesz.mit.edu (John C. Baez)
Subject: Re: Religion & Physics Don't Mix
Organization: MIT Department of Mathematics, Cambridge, MA
Date: Fri, 6 Nov 92 02:00:49 GMT

In article <1dbo90INNt4k@hpsdlss3.sdd.hp.com> johno@sdd.hp.com (John Ongtooguk) writes:
>In article <1d9tejINNq6p@chnews.intel.com>, bhoughto@sedona.intel.com (Blair P. Houghton) writes:
>|> 
>|> Science is truth, and truth is science. They are one and the same. 
>
>  If the truth is always changing then what is it after it changes ?

"Error."
From: joe@astro.as.utexas.edu (Joe Wang)
Newsgroups: sci.physics
Subject: Re: The solar neutrino problem - more confusing than *ever* before!
Keywords: Neutrinos, New Physics, Fusion
Date: 10 Nov 92 22:00:04 GMT
Organization: McDonald Observatory, University of Texas @ Austin

In article <1992Nov5.050258.4240@isus.UUCP> hoyt@isus.UUCP (Hoyt A. Stearns jr.) writes:
>The energy generation inside the sun comes not from fusion,
>but the thermal destruction of heavy elements.  Each element has a
>temperature above which it converts to pure energy. 

If this is true, then 

1) Why are there any neutrinos at all?  If the source of energy is due
to thermal destruction of heavy elements into pure energy, then where
are the neutrinos that we do see coming from?

2) What about white dwarf stars?  These are presumably the burned out cores
of stars, and they seem to be pure helium with no heavy metal content.

3) Why hasn't this energy conversion been detected in earth-bound experiments?

4) Where do the heavy elements come from in the first place?  In the standard
model, the universe starts out as essentially all hydrogen and helium?

5) If the energy from stars comes from heavy elements, then presumably
stars with lower abundances of metals ought to be much dimmer than
similar stars (same mass) with heavy elements.  They don't seem to be.

6) Have you calculated the impact of your model on stellar evolution?
Standard stellar theory says that stars become red giants when the core
runs out of hydrogen?  Does your model explain why red giants exist?

7) Can you give me the Temperature vs. Luminosity relationship that your
model predicts for stars?  The standard model gives a relationship which 
fits the observations closely.  Do you have predictions about the lifetime
of stars and energy generation rates?  These ought to be easy to calculate.

8) If a atomic nuclei turns into energy, you don't conserve charge.  Very
soon, a star will be extremely charge imbalanced and this ought to have 
observable consequences in spectra.  Why doesn't this happen?

It took me about 15 minutes to come up with these questions.  It seems
that you need to answer the above questions before you can use it to
answer the solar neutrino mystery.  Otherwise, you seem to be "solving"
one mystery at the cost of opening up dozens of other ones.

>These discontinuities cause oscillation of output (variables), and
>eventually, supernovae.

Explain.  Standard variable theory states that variables are due to an
instablity of the envelope in the star.  From standard variable
theory, you can get predictions about the temperature vs. luminosity
function of stars as well as predictions about their periods.  Does your
model do this?

Also, it seems that your model makes predictions about the elemental
abundances observed in supernova.  Can you share them with us?  Also,
can your model explain the abundance of Ni-57 in supernova explosions?
Conventional supernova theory says that there is a lot of it because
that part of the periodic table is where the most stable elements are
found.  Since your model of nuclear interactions is different, can you
explain this abundance?
From: pratt@Sunburn.Stanford.EDU (Vaughan R. Pratt)
Subject: Re: What's a manifold?
Organization: Computer Science Department,  Stanford University.
Date: Sat, 7 Nov 1992 02:37:54 GMT

In article <1992Nov6.190913.18507@nas.nasa.gov> asimov@wk223.nas.nasa.gov (Daniel A. Asimov) writes:
>HERE is an example to illustrate the pitfalls of the "extrinsic" approach:
>
>	Consider finite matric spaces.  One could use the approach of defining them
>	as any finite subset of Euclidean space with the inherited distance function.
>	Or one could use the abstract approach of a distance function with the usual
>	metric space axioms.
>
>	However, the first approach will fail to include some (usual) metric spaces 
>	containing only 4 points:  Let X = {A,B,C,D} with d: XxX -> R the metric 
>	defined via d(A,B) = d(B,C) = d(C,A) = 7 and d(A,D) = d(B,D) = d(C,D) = 4.
>	It is not difficult to show that this metric space cannot occur as a subset 
>	of a Euclidean space of any dimension.  (Example due to Richard Schroeppel)

This is very nice!  I wish there were as beautiful an example for
manifolds.  The thing about metric spaces is that the abstract
definition is *very* beautiful (I like generalizing this by dropping
symmetry and "d(x,y)=0->x=y" since this is yet simpler and moreover
then admits many objects that arise in computer science).  If there
were as simple and beautiful an abstract definition of manifold as
there is of (generalized) metric space you wouldn't hear any complaints
from me.  You can't make analogies like these stick in situations like
these!

(Beautiful: I said it thrice, beauty must be truth.)
-- 
Vaughan Pratt				There's no truth in logic, son.
Xref: sparky sci.physics:18295 alt.fan.dale-bass:38 alt.guitar.bass:1850 talk.bizarre:37063
From: bhoughto@sedona.intel.com (Blair P. Houghton)
Newsgroups: sci.physics,alt.fan.dale-bass,alt.guitar.bass,talk.bizarre
Subject: Re: High popularity rating
Date: 6 Nov 92 18:28:21 GMT
Organization: Intel Corp., Chandler, Arizona
NNTP-Posting-Host: alfalfa.intel.com

In article <2153@eagle.ukc.ac.uk> aw3@ukc.ac.uk (Alan Wilson) writes:
-In article <s0454850.14.0@let.rug.nl> s0454850@let.rug.nl (J.P. Prenger) writes:
->Hey, is there anybody out there?
->
->If so, please tell me, what's this newsgroup about?
->& who the fuck is dale bass?
->
->Jan Peter Prenger
->E-mail: s0454850@let.rug.nl
-
-Try reading sci.physics occasionally! I presume its the same guy, but is
-he good enough to merit an entire news group to himself? Only time will tell

Dale (Corky) Bass is the inventor of the Bass-O-Matic.

				--Blair
				  "Donjoonoennythin?"
Newsgroups: sci.physics
Subject: Simple Sin Wave form Question
From: Steve_Grant@kcbbs.gen.nz (Steve Grant)
Date: 8 Nov 92 04:29:33 GMT
Organization: Kappa Crucis Unix BBS, Auckland, New Zealand

Hello,
     As some of you may or may not know when a number is pressed on 
the key pad of a telephone two tones are emitted, I wish to copy the 
resulting sound to make a autodialer but- I am told by the people in 
telecom land that the resultant frequencie is NOT the average. I know 
that SIN (x + y) = SIN(x)COS(y) + COS(x)SIN(y) but when i plot this 
on my plotting program for say the frequencies of say 1209, 657 it just 
evaluates the numbers and draws a straight line parallel to the x axis, 
is the y value of this line the resultant freq? ie:

SIN (1209 + 657) = SIN(1209)COS(657) + COS(1209)SIN(657)

I know that I should be able to figure this one out by myself but cannot 
and are getting very frustrated. Any help in the form of dummy proof 
explinations would be very much appreciated.

Al Grant

PS the question is: A) is the freq. the average?
                    B) whats the equation?
From: Richard.Mathews@West.Sun.COM (Richard M. Mathews)
Newsgroups: sci.physics
Subject: Re: Simple Question on Color
Date: 5 Nov 1992 23:40:14 GMT
Organization: Sunsoft Inc., Los Angeles, CA.
NNTP-Posting-Host: astro
Keywords: color, tv, violet
Originator: richard@astro.West.Sun.COM

music@erich.triumf.ca (FRED W. BACH) writes:
>     Yes, and speaking of color tv, since my favorite color family is 
> the violets, it always bugs me when true violets (not blue+red phony
> attempts at it) are picked up by a color-tv camera.  Now I don't
> know what *every* camera out there does, but some will simply *not*
> pick up this violet and display it.  All you get is a pure bright
> blue.  Is this because the true wavelength of the violet is outside
> (i.e., not between) the spectral responses of the phosphors used?

I would think that you get a pure blue because the camera's red detector
does not have the same small peak in the violet that our eye's red cones
do.  Only the camera's blue detector responds to the violet light, so the
camera produces a blue image.

If the camera's red detector did have a tiny peak of violet sensitivity
then the camera would detect a combination of red and blue.  What would
appear on your screen would be purple.

Without a TV which includes a violet phosphor, there is no way that any
camera can make your TV show violet.

     Richard M. Mathews			F oster 
					 E stonian-Latvian-Lithuanian
Richard.Mathews@West.Sun.COM		  I ndependence and
					   F reedom!
From: johan@blade.stack.urc.tue.nl (Johan Wevers)
Newsgroups: sci.physics
Subject: Re: Religion & Physics Don't Mix
Date: 6 Nov 92 10:32:41 GMT

Cameron Randale Bass writes:

>>>'Science vs. Religion' is
>>>about as sensible a contest as 'Cooking vs. Linguistics' or 'Sportsmanship
>>>vs. Geology'

>>No, it's experimental proof vs. no proof at all.

> You cannot even offer 'proof' in science that the next experiment
> will show the same thing as the last.  I suggest you reevaluate
> the 'proof'-nature of science.  As far as religion goes, 'proof'
> is not necessary within faith.

As I noticed before, your view about science seems instrumentalistic to me.
I agree with you that the induction principle fails. But the main thing
for science IMO is that experiments can point us to a theory. After we
know that theory, we can predict the outcome of an experiment.
-- 
********************************************************** 
* J.C.A. Wevers                *   The only nature of    * 
* johan@blade.stack.urc.tue.nl *   reality is physics.   * 
**********************************************************
From: matt@physics2.berkeley.edu (Matt Austern)
Newsgroups: sci.physics
Subject: Re: No big crunch?
Followup-To: sci.physics
Date: 5 Nov 92 10:24:23
Organization: Lawrence Berkeley Laboratory (Theoretical Physics Group)
	<1992Nov3.141351.22224@sei.cmu.edu> <1d78l7INNhu2@agate.berkeley.edu>
Reply-To: matt@physics.berkeley.edu
NNTP-Posting-Host: physics2.berkeley.edu
In-reply-to: ted@physics1's message of 4 Nov 1992 01:22:47 GMT

In article <1d78l7INNhu2@agate.berkeley.edu> ted@physics1 (Emory F. Bunn) writes:

> I believe that the effect Matt is referring to is the following:
> If you measure the orbital speeds of objects in our galaxy, and
> use the laws of mechanics to determine the amount of matter in the
> galaxy, you find a need for some dark matter.  If you do a similar
> experiment over a larger distance scale, say by measuring the orbital
> properties of a pair of binary galaxies, you need an even larger
> density of dark matter.  If you keep going to still larger scales,
> you find an even greater required density.

Yes, that's more or less what I meant.

I just want to emphasize something that maybe I didn't stress enough
in my original post: these measurements are difficult.  In particular,
these largest-scale measurements involve analyzing the motion of
galactic clusters, picking out that part of the motion that doesn't
seem to be from the overall expansion of the universe, deducing what
the concentrations of matter might be that would produce those motions
(this is done with rather complicated numerical programs), and then
comparing it to the visible matter that we see in the galaxies.

There's an enormous potential for error here.  In other words: I think
that this trend (more dark matter at larger scales) is interesting,
but shouldn't necessarily be taken seriously until we have a better
idea of how to control these uncertainties.


--
Matthew Austern                   Just keep yelling until you attract a
(510) 644-2618                    crowd, then a constituency, a movement, a
austern@lbl.bitnet                faction, an army!  If you don't have any
matt@physics.berkeley.edu         solutions, become a part of the problem!
From: crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass)
Newsgroups: sci.physics
Subject: Re: GR with no Einstein? (Was: Re: No big crunch?)
Date: 7 Nov 92 03:40:56 GMT
Organization: University of Virginia

In article <1992Nov6.232435.15628@galois.mit.edu> jbaez@riesz.mit.edu (John C. Baez) writes:
>In article <1992Nov6.042306.899@murdoch.acc.Virginia.EDU> crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) writes:
>
>>     Suppose, as I have been, that you *don't even have* GR.
>>     In 1906, there was no certainty that GR would be developed.
>>     In fact, if Einstein had died in 1906, I'm quite sure it 
>>     wouldn't have been.
>
>Oh good, let's argue about this, since it is utterly contrafactual.  I'm
>sure GR would have been developed (though not in 1906!).  Einstein was
>not the only person working on trying to come up with relavistic
>theories of gravity.  Other people came up with some that were getting
>sort of close (sorry, I don't have references on this - it would be fun
>to know just *how* close).  And more importantly, the mathematical
>infrastructure had already been laid by Riemann and was being studied by
>Cartan and Hilbert, who were sort of into physics.  So I am quite sure
>someone would have come up with GR after a while.

     Riemann's attempts were widely considered to be failures.  It
     is my contention that Einstein was fairly lucky to have been able
     to study Riemann before 1900.  A priori there is no reason to believe
     that riemannian geometry will be useful in that context at all.
   
     And Cartan himself once bemoaned to Einstein that he did not have
     the physical background to pursue various physical subjects.  I hardly
     think this is promising grounds for an Einsteinless GR.  

     It is also true that the fact Einstein was working on the problem
     provided some of the impetus in the 1910's for such work.  However, the
     fact that GR was basically roundly ignored from 1917 until the early 60's
     lends credence to the basic assertion that GR without Einstein would
     have not been certain.  Even nearly 70 years later, however, the number 
     of errors and contradictions in GR literature is astounding (Damour, In
     "300 Years of Gravitation" Cambridge (1987)).  It is an extremely
     difficult and complex formulation, a priori, and I feel that without
     Einstein's rather prodigious physical insight, it would still lie
     undiscovered.

     I don't think I'm alone in this.  Maybe we should ask John Wheeler
     to speculate?

                            dale bass



-- 
C. R. Bass                                          crb7q@virginia.edu        
Department of Mechanical, 
     Aerospace and Nuclear Engineering
University of Virginia                              (804) 924-7926
Newsgroups: sci.physics
From: torkel@sics.se (Torkel Franzen)
Subject: Re: EINSTEIN'S SCHOOL DAYS
Organization: Swedish Institute of Computer Science, Kista
Date: Sun, 8 Nov 1992 00:17:11 GMT

In article <BxDAnL.Bnp@helios.physics.utoronto.ca> neufeld@helios.physics.
utoronto.ca (Christopher Neufeld) writes:

   >The quick answer, according to news reports which came out about two
   >years ago, is that Einstein was always a very good student throughout
   >his schooling.

  Indeed Pais, in "Subtle is the Lord..." says that "contrary to popular
belief, [Einstein] earned high marks in elementary as well as high school."
Newsgroups: sci.physics
From: zellner@stsci.edu
Subject: Physics, religion, & mysticism
Organization: Space Telescope Science Institute
Distribution: na
Date: Tue, 10 Nov 1992 23:28:33 GMT

Tim Dodd, cegtitd@prism.gatech.edu, writes:

>  How do we decide if a statement is true?  We devise an empirical test 
>  and let reality tell us if the statement is accurate.

Sure, if you can.  When did you last try the Eotvos experiment?  Or did 
you (heavens forbid!) take the results of that experiment "on faith"?  And
do you have a good experiment to test superstring theory?

>  Religious thought is typified by "mystical mode".  In this mode of 
>  thought, it is recognized that there exists a level of "truth" or 
>  "reality" to which mere rational thought does not have access.  

There certainly might be levels of reality to which neither experience nor 
experiment have access.  That isn't the same thing as the limits of ration-
ality.  If a proposition isn't falsifiable, it isn't science.  But that 
doesn't say whether it's true or false, or even rational.  According to the 
Gospel of John, Jesus said "Before Abraham existed, I already was."  Science 
cannot touch that one, but it's a simple statement of fact, either true or 
false, with nothing "mystical" about it. 

>  These two modes of thought are mutually exclusive.  Neither can encompass
>  the other:  they cannot be mixed.  You can think mystically or rationally,
>  but you cannot do both at the same time.  

I don't see that much difference.  I can read one of St. Paul's letters with 
the exactly the same thought-modes that I read a physics book or a computer 
manual:  with every attention to detail, and with the DEFAULT assumption that 
the writer knows much more about it than I do (yet).  What is this saying?  
Do I understand it, or did I miss an essential point?  Is it internally 
consistent, and is it externally consistent with other things that I know or 
believe?  If I am having trouble with it, might that be because I have some 
prior mis-conception that is getting in the way?  Or might it be because I 
lack the necessary background?  If so, where can I get the background?  And
if I decide to reject it as pure baloney, on what basis?

Where's the "mysticism" in all that?

Ben
From: dave@prim.demon.co.uk (Dave Griffiths)
Newsgroups: sci.physics
Subject: Re: The size of electrons, and Fanciful misc SAGA
Date: 9 Nov 92 15:52:16 GMT
Organization: Primitive Software Ltd.

In article <1992Nov8.231641.28334@CSD-NewsHost.Stanford.EDU> pratt@Sunburn.Stanford.EDU (Vaughan R. Pratt) writes:
>
>You are forgetting that scalability is a big concern today in CS.
>Digital models don't scale gracefully, the bits look bigger.  Smooth
>scalability demands a smooth view of what one is scaling.  A digital
>view inhibits scalability.
>

Can you give an example of where scalability becomes a problem? Of course
things don't look the same on smaller and smaller scales, but that's the
whole point. If you take a smooth rod of metal, you can keep chopping it
in half, but eventually you'll run up against a barrier of individual atoms -
your scalability disappears.

I think the notion that continuums exist is based upon our naive physical
intuitions about the smoothness of things in the real world. At the back of
our minds is the idea that that continues down to the microscopic scale. We
now know that this is not the case.  Working with digital computers allows 
us to form new physical intuitions about the structure of the world, ones 
that (to me) make more sense.

Smoothness is ingrained very deep in physicists view of the world. It
amazed me to read Feynman discussing a model of an electron as a smooth
ball of charge (not to mention "point" charge) with all the mental problems
that provokes of imagining the "stuff" of which an electron exists and chopping
it in half etc.

A digital view of the world neatly gets rid of all these problems. The only
thing left to do is invent the new physics. :)

Dave Griffiths
From: sichase@csa2.lbl.gov (SCOTT I CHASE)
Newsgroups: sci.physics
Subject: Re: Compelling Mysteries (II)
Date: 11 Nov 1992 11:44 PST
Organization: Lawrence Berkeley Laboratory - Berkeley, CA, USA
Distribution: world
NNTP-Posting-Host: 128.3.254.197
News-Software: VAX/VMS VNEWS 1.41    

In article <1992Nov11.140007.16660@ulrik.uio.no>, jarleb@diana.uio.no (Jarle Brinchmann) writes...
> 
>bursts are uniformly distributed over the sky, and recent results seem to 
>indicate that. 
> 
>If this is right, that will clearly indicate that these bursts are extra-
>galactic in origin (I will _not_ say prove, because one could think of
>the possibility that the bursts could come from the spherical halo of our

Alas, but simple ideas are not always right.  The data also indicate that that
there is an absence of weak sources, i.e., if you plot the intensity 
distribution that you expect for a uniform extragalactic halo, you find
that the data drop off too quickly after a certain intensity minimum.  It's
as if there are no *far* bursters, even though they are uniformly distributed
in the sky.

This suggests, at best, an in-between solution - bursters are associated
with our galaxy, but are uniformly distributed in a sphere.  There are problems
building such models as well, but I can't remember the details off the top
of my head.  

-Scott
--------------------
Scott I. Chase			"It is not a simple life to be a single cell,
SICHASE@CSA2.LBL.GOV		 although I have no right to say so, having
				 been a single cell so long ago myself that I 
				 have no memory at all of that stage of my 
				 life." - Lewis Thomas
Newsgroups: sci.physics
From: sarfatti@well.sf.ca.us (Jack Sarfatti)
Subject: Ramsay's error is <a,e,+|a,o,+> = 0
Organization: Whole Earth 'Lectronic Link
Date: Wed, 11 Nov 1992 06:28:15 GMT


Ramsay writes:

"In order for the evolution to be unitary, we must have <a,e,+|a,o,+> = 0."

Why? Both |a,e,+> and |a,o,+> are identical in spin space and they both
evolve to |h>.  In fact

<a,e,+|a.o.+> = e^ix

Ramsay is confused. The proper orthogonality relations are:

<a,e,+|a,e,-> = 0

<a,o,+|a,o,-> = 0

I will comment on the rest of Ramsay's reamrks in another posting.