HDTenEightyP/NetNews huggingface dataset:
From: columbus@strident.think.com (Michael Weiss)
Newsgroups: sci.physics
Subject: Re: Entropy
Date: 20 Aug 92 17:13:57 GMT
Article-I.D.: strident.COLUMBUS.92Aug20101357
Organization: Thinking Machines Corporation, Cambridge MA, USA
NNTP-Posting-Host: strident.think.com
In-reply-to: jmgreen@pilot.njin.net's message of 20 Aug 92 02:04:38 GMT

Jim Green asked why the "Carnot cycle" concept of entropy was equivalent
to the usual statistical definition, S = k ln W.

One poster suggested Reif's book "Statistical Physics".  This is quite
good.  Actually, any standard textbook on statistical mechanics will
contain a derivation of the equivalence (under suitable hypotheses).

On more popular level, P.W.Atkins' book "The Second Law" (Scientific
American Library) provides nice intuition about this, and much else about
entropy (e.g., why don't oil and water mix, if mixing things increases the
disorder?)  Atkins' outlook is slanted towards physical chemistry, one of
the big consumers of thermodynamics.

There are at least three other faces to the concept of entropy: Shannon's
notion from information theory; Chaitin's definition in algorithmic
information theory; and the "entropy of a black hole", which (I am told) is
proportional to its surface area.  I am familiar with the first two of
these, but would enjoy reading anything anyone has to offer on "black hole"
entropies.
Newsgroups: sci.physics
From: hagerman@ece.cmu.edu (John Hagerman)
Subject: Re: any equations that can help determine ice melting rate?
Organization: Carnegie Mellon University
Date: Fri, 21 Aug 1992 18:47:29 GMT

Someone suggested assuming still-air conditions for calculating the
heat loss to air, and someone (else?) claimed that ground contact
would be the main factor.  How much will convection change the air
temperature distribution?  Enough to make air loses significant?

- John
--
hagerman@ece.cmu.edu
Newsgroups: sci.physics
From: patton@phy.uab.edu (David Patton)
Subject: Re: Preprint Servers: Is there a list of them
Reply-To: patton@phy.uab.edu
Organization: University of Alabama at Birmingham
Date: Wed, 12 Aug 1992 20:50:28 GMT



send email to following with HELP in the subject line and nothing in the body of the
message

alg-geom@publications.math.duke.edu  (algebraic geometry)
astro-ph@babbage.sissa.it            (astrophysics)
cond-mat@babbage.sissa.it            (condensed matter)
funct-an@babbage.sissa.it            (functional analysis)
hep-lat@ftp.scri.fsu.edu             (computational and lattice physics)
hep-ph@xxx.lanl.gov                  (high energy physics phenomenological)
hep-th@xxx.lanl.gov                  (high energy physics formal)
lc-om@alcom-p.cwru.edu               (liquid crystals, optical materials)
Newsgroups: sci.physics
Newsgroups: sci.physics


Thanks,

The diagram did have other participants that I didn't mention. I was
only looking at that one event in the diagram (oops!). If I understand
correctly, this non conservative event has to eventually end up
in a conservative state, and the time for conservation to "come back"
depends on the amount of energry not conserved and plancks constant.

I'd like to learn more. Perhaps you could recommend a good book. I've
got a BSEE and an MSEE, with a lot of math background. I've seen
some QM, but not quantization of the electromagnetic field. I'd
like to read and understand something (QED?) at the graduate level.

Please email any suggestions. Thanks again,

--------------------------------------------------------------------------
Ric Peregrino     c/o Hewlett Packard Co.        I represent only myself
ric@spd.hp.com    1501 Page Mill Rd. Bldg. 5M    High low, sell buy
415-857-7526      Palo Alto, CA 94304            Do DC photons exist?
--------------------------------------------------------------------------
Xref: sparky sci.physics:13352 sci.skeptic:14844 alt.folklore.science:3096
From: quest@iowegia.uucp (Steve J. Quest)
Newsgroups: sci.physics,sci.skeptic,alt.folklore.science
Subject: Re: The dangers in microwaved food...
Date: 22 Aug 92 18:39:45 GMT
Organization: Iowegia Waffle BBS, Clive IA USA, +1 515 226 2156

matmcinn@nuscc.nus.sg (Mcinnes B T (Dr)) writes:

> there are serious health risks in eating.


        I personally am more afraid of bacterial contamination in 
food or pesticide residues.  Something we should note here is that 
microwave radiation is electromagnetic, and is NOT ionizing.  
Irradiated (ionizing) food is safe to eat, as astronauts do it all 
the time.  In fact, if I could buy irradiated food, I would do so, 
as it can be stored for long periods of time and contains 
absolutely NO bacteria!  I have no solution for pesticide residues 
in food however.

        Rest assured everyone, microwaves are only dangerous if 
the radiations are being absorbed by your body.  In other words, 
keep the door closed while cooking your food and you are ok.  
There is no electromagnetic contamination of food either......sq
Xref: sparky sci.physics:12966 sci.astro:9014
From: murphy@npri6.npri.com (David P. Murphy)
Newsgroups: sci.physics,sci.astro
Subject: Re: Fossil Paradox (was: Structure of Time)
Date: 17 Aug 92 16:49:56 GMT
Distribution: world
Organization: NPRI, Alexandria VA


 >All this stuff about going back in time and changing things so that
 >our future will be different might work, but I think people underestimate
 >the true effects it would have.
 >
 >In chaos theory the "butterfly effect" is mentioned. Well if I went back in
 >time, stood there for a few minutes and then came forward I think that would
 >have a HUGE impact on our world. Consider the fertilisation process. 
 >The things that decide which sperm gets to the egg. The slightest change
 >in that and you're going to have a whole set of different people.
 >
 >In my journey back I may just catch the eye of somebody and delay his/her
 >next sexual act by one second. This may lead a different sperm to the egg
 >and different children etc.
 >
 >There was a short story like this where a guy trod on a butterfly and totally
 >changed everything. What was it called?
 >
 >Jim Palfreyman (jim@r140.tased.edu.au)

"A Sound Of Thunder" by Ray Bradbury.

and i don't know about _you_, jim, you stud muffin, but you (or a female
time-traveller) could catch _my_ eye all day long and have only the slightest
chance imaginable of affecting _my_ next sexual act.  of course, i wish
this were not true, but it is.  also, though my ego is loathe to admit it,
i am not exactly at the top of the world's Movers-And-Shakers list,
and any time-hopper with a gun and a bullet could off me at any time
secure in the knowledge that history hasn't even quivered.  :-)

ok
dpm
-- 
murphy@npri6.npri.com 602 Cameron St. Alexandria, VA 22314 (703) 683-9090

              When every one is dead the Great Game is finished.  Not before.
                              --- Hurree Babu, "Kim"
From: crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass)
Newsgroups: sci.physics
Subject: Re: Facts and Values
Date: 22 Aug 92 17:10:05 GMT
Organization: University of Virginia

In article <MeZaD2a00VogMG8kRB@andrew.cmu.edu> ag3l+@andrew.cmu.edu (Arun K. Gupta) writes:
>
>When physics fails to reveal the location of heaven, the existence of
>soul, and reveals the insignificant rather than central position of 
>human existence in the universe, then all the above lose their logic,
>and we begin to find them wrong.  So much so, that a modern person
>can barely understand why those practices ever existed and would
>outright label them as wrong and evil.  But, within the beliefs and 
>knowledge those ancient societies had, those practices were justified.
>
>Thus  science does have an impact on values. 
>
>Another example would be the attempts to give a scientific basis to
>racism -- IQ tests,  measuring of head sizes, etc. etc.. The imagined
>positive results, and the later discrediting of those results all had an
>effect on the legitimacy of racism.

     Actually the measurement of head sizes may be currently being
     surpressed because of an overriding concern that unpalatable
     results may be found.  There has been discussion of such in 
     recent Nature letters and articles (see the rather interesting
     attitude of John Mattox, Nature's editor in 358:187 (1992), 
     in which he states that 'unpalatable' results should have
     to pass more stringent tests.  Responses are 358:532 (1992)).  
     Basically, a proponent of race-related IQ, J. Phillip Rushton, has 
     found evidence of a racial correlation with cranial capacity in a large 
     US army database (6325 records).  He is having a difficult time
     publishing his results.

     Though I hasten to add that the interpretation of such results
     is certainly questionable, I find it interesting that Mattox would 
     assert a higher standard for 'unpalatable' results than for
     ridiculous results (c.f. the Benveniste affair).

                                   dale bass
-- 
C. R. Bass                                           crb7q@virginia.edu
Department of Mechanical and Aerospace Engineering
University of Virginia
Charlottesville, Virginia                            (804) 924-7926
Newsgroups: sci.physics
From: brahm@cco.caltech.edu (David E. Brahm)
Subject: Re: High Energy Physics Phenomenology
Summary: CFD: PDB subgroups
Organization: California Institute of Technology, Pasadena
Date: Tue, 18 Aug 1992 23:47:15 GMT

moorthy@ferrari.cs.rpi.edu (Moorthy) writes:
> I would like to know the electronic mailing lists/archival sources for
> $K_{L} --> \pi \mu \nu \gamma.$

"sci.physics.particles.mesons.KL.decays.semileptonic.pi_mu_nu_gamma"?

Article 1> KL -> pi e nu gamma occurs; why don't we see -> pi mu nu gamma?
Article 2> The SSC will see it.
Article 3> KL decays don't justify $8G stolen from the aerospace industry!
Article 4> My daughter says KL decays pain the space potato's soul.
Article 5> Survey: Where do KL's go when they die?

Hey, let's start a newsgroup for every entry in the Particle Data Book!

ObSeriousness:  I think a good place to look for such things is the SPIRES
database PARTICLES (or REACTIONS for A + B -> ...), which reproduces the
PDB.  I see KL -> pi e nu gamma (BR=1.3%), but not KL -> pi mu nu gamma.

--
Staccato signals of constant information,  |  -- David Brahm
A loose affiliation of millionaires and    |  (brahm@cco.caltech.edu)
  billionaires and Baby ...                |---------------------------
These are the days of miracle and wonder,  | Disclaimer:  It was a joke,
And don't cry, Baby, don't cry, don't cry. |   just a harmless ARGHHH...
Newsgroups: sci.physics
From: jbaez@riesz.mit.edu (John C. Baez)
Subject: Re: Symmetries, groups, and categories
Organization: MIT Department of Mathematics, Cambridge, MA
Distribution: na
Date: Fri, 21 Aug 92 18:17:01 GMT

In article <mcirvin.714344140@husc8> mcirvin@husc8.harvard.edu (Mcirvin) writes:
>andrew@rentec.com (Andrew Mullhaupt) writes:
>
>>Hey while we're hammering physics for ill-chosen terminology, can we at least
>>change it to 'renormalization monoid'?
>
>And "pseudometric tensor" in relativity.
>
>My algebra's rusty.  What's the difference between a monoid and a
>semigroup?  Some textbooks say that it's really a renormalization
>semigroup.  They give the nature of the composition law as evidence.
>"Monoid" is more general, right?

I believe that there are some difference in opinion about these
definitions in the math literature, but the most widely used definitions
these days are as follows.  A semigroup is a set with an associative
binary operation.  If it has an element that is both a right and left
identity, it is called a monoid.  (Easy to remember, because the "mono"
refers to the identity, or "unit".)

There used to be a rock band at Princeton called Monoid, because it was
a "semigroup with an identity".

>What I find strange is that the term is used even though the
>[monoid/group/semigroup] nature of the beast isn't particularly
>illuminating or important.  The term seems to be the result of
>enthusiasm for group theory bleeding into places where it has
>little relevance.

Well, scaling is a monoid (the real numbers in (0,1] form a
monoid under multiplication), or if you allow "scaling up," a group (the
real numbers > 0 form a group under multiplication).  But I am probably
one of millions of mathematicians who were sorely disappointed to find
out that the "renormalization group" was such a boring group.  What's
interesting is not this group per se but its ACTION on the physical
system one is studying (the "renormalization group flow" on some space
of coupling constants).  So I agree that it's a bad term.

Newsgroups: sci.physics
From: jcf@world.std.com (Joseph C Fineman)
Subject: Re: Order-of-Magnitude problems
Organization: The World Public Access UNIX, Brookline, MA
Date: Sat, 22 Aug 1992 00:35:40 GMT

Rob:

I wrote this reply several days ago, but am new to Internet, & have taken
this long to figure out how to post it.  In the meantime a good deal of it
has appeared in other followups, but some of the details may still be of 
interest.

Consider first the *classical* problem of a pencil balanced on its
point (at 0 K, in vacuo).  This is just an upside-down pendulum, and
has the same differential equation as an ordinary pendulum with the
sign of the force term reversed.  Once again we may make the
approximation sin(theta) = theta, this time not because theta will
remain small, but because once it becomes large we may deem the pencil
to have fallen over.  Then the motion, instead of being A sin(OMEGA t)
+ B cos(OMEGA t), is A exp(OMEGA t) + B exp(- OMEGA t) (same OMEGA),
where only the first term is of interest.  Let the pencil be given a
tiny initial displacement theta(0) and/or angular velocity omega(0) at
t = 0; plugging in, we find A = omega(0)/(2 OMEGA) + theta(0)/2.
Hence the time it takes for theta to become of order 1 is about
- (1/OMEGA) ln{(1/2)[theta(0) + omega(0)/OMEGA]}.

Now the *handwaving* step.  It seems plausible that the amplification
of the quantum-mechanical fluctuations takes place almost entirely in
the classical regime, so that the latter can be incorporated entirely
in the constraint they place on the initial conditions.

Finally the *q.m.*  Let I be the moment of inertia.  Then theta and
I omega are canonically conjugate, so theta(0) and omega(0) cannot
both be zero; at best theta(0) omega(0) is of order h/I.  Choosing
theta(0) subject to this constraint to minimize the quantity in { } &
thus maximize the lifetime, we obtain t = - (1/OMEGA) ln sqrt[h/
(I OMEGA)].  Plugging in reasonable values, we find that it takes
about a minute for the pencil to fall over.

If I were Von Neumann, I would supply a rigorous justification of the
handwaving step.  If I were Fermi, I would have intuited the logarithm
& supplied its argument on dimensional grounds.  Perhaps you can do
something of the sort.

Yours &c, Joe
Newsgroups: sci.physics
From: jbaez@riesz.mit.edu (John C. Baez)
Subject: How to make big bucks using supersymmetry
Organization: MIT Department of Mathematics, Cambridge, MA
Date: Thu, 13 Aug 92 17:47:37 GMT

In article <12AUG199220325953@zeus.tamu.edu> dwr2560@zeus.tamu.edu (RING, DAVID WAYNE) writes:
>jbaez@nevanlinna.mit.edu (John C. Baez) writes...
>>I still wish I
>>could place some bets for more that 1 cent on supersymmetry though --
>>anyone around REALLY believe there's a >50% chance of it being confirmed
>>within our lifetimes?
>
>You are a wimp. :-)

Oh yeah?  Wanna step outside?  You're the one who wouldn't take a $4/$6
bet and wanted to tone it down to a check for one measly cent!  I'd like
to actually make some money off of supersymmetry!  This bet may be its
only practical application!

>I would be happy to make your side of the bet 'worthwile'
>to you, but I was hoping we could be a little classier than sending money!
>You can choose your own reward, so long as it is within a grad student's
>budget. If I remember correctly, Hawking and Thorne wagered a subscription
>to Playboy, over the possible discovery of a black hole (can anybody verify
>this?) If you insist on real money, then I want the deadline pushed to 2010
>as Scott suggests.

Are you planning on being in grad school until the year 2010?  In any
event, to make it mildly exciting, I would propose to give you $40 if
strong evidence for SUSY is obtained by 2010, if you give me $60 if it's
not.  This would count as proof that you believe your original statement
that SUSY has a 60% chance of being true.

>In any case, I want a check for 1 US cent, with the memo:
>'Strong evidence for SUSY.' I hope that won't be TOO much of a burden, I know
>how damaging such things can be to the reputation of a future big shot! :-)

If this 1-cent bet is all you're up for, how much money would you be
willing to give me if they DON'T find strong evidence?  I'm sorry if I
seem so crass, but frankly a subscription to Playboy is not my idea of
"classy".  :-)  Feel free to propose anything.

Then we will have to get some idea of what counts as 'strong evidence
for SUSY'.  Convergence of coupling constants alone does not cut it in
my opinion.
From: weemba@sagi.wistar.upenn.edu (Matthew P Wiener)
Newsgroups: sci.physics
Subject: Re: Weak interactions, biology and the SSC
Date: 17 Aug 92 13:41:44 GMT
Reply-To: weemba@sagi.wistar.upenn.edu (Matthew P Wiener)
Organization: The Wistar Institute of Anatomy and Biology
In-reply-to: gilligan@bldrdoc.gov (Jonathan Gilligan 303-497-3861)

In article <4867@dove.nist.gov>, gilligan@bldrdoc (Jonathan Gilligan 303-497-3861) writes:
>I have a hard time believing that biological chirality developed due
>to a part-in-10^7 or smaller effect that's more than four orders of
>magnitude below the thermal noise.

Why is that hard to believe?  Directional subnoise effects, given enough
time (and we're talking teraseconds), can overwhelm noise.  That was, for
example, the principle behind COBE's recent 3K anisotropy detection.

>However, even if it were the case that the weak force were
>biologically significant, I think that results relevant to biology
>would be more likely to come from work like Carl Wieman's.

No kidding.  What do you think I've been talking about?  I have not
specified *any* scenario, simply because no one knows, me least of all.

>							    Wieman has
>measured the the weak mixing angle by measuring parity violating
>electronic transitions in atomic cesium. [...]

Parity violation on the atomic level is currently a lively cottage
industry.  Numerous such effects are known.  Without even looking, I
ran into a new World Scientific conference proceedings on this topic
which showed up at the Penn library this past week.
-- 
-Matthew P Wiener (weemba@sagi.wistar.upenn.edu)
Xref: sparky sci.physics:13195 sci.space:12069 rec.gambling:4535
From: decot@cup.hp.com (Dave Decot)
Newsgroups: sci.physics,sci.space,rec.gambling
Subject: Re: Nevada Casino - 200 miles up
Date: 21 Aug 92 03:14:40 GMT
Organization: Hewlett-Packard, Cupertino, CA
X-Newsreader: Tin 1.1 PL3

bhoughto@sedona.intel.com (Blair P. Houghton) writes:
: I'll leave that to the rocketeers in sci.space.  They'll
: probably suggest a better orbit (although I think
: geosynchronous is a bit out of the way for junkets...).

It would float away because there is no atmosphere in the sky.

Dave
Xref: sparky sci.physics:13158 alt.folklore.urban:21823 sci.electronics:14652
From: acase@reed.edu (Andrew Case)
Newsgroups: sci.physics,alt.folklore.urban,sci.electronics
Subject: Re: Fun with droplets
Date: 20 Aug 92 18:55:57 GMT
Distribution: usa
Organization: Reed College, Portland, OR

In article <1992Aug20.013001.25066@eos.arc.nasa.gov> jbm@eos.arc.nasa.gov 
(Jeffrey Mulligan) writes:
>adrian@csqx.cs.rhbnc.ac.uk (A Johnstone) writes:
>
>>Whilst I'm on the subject (probably this is not the place for it but here 
>>goes anyway) has anybody else noticed the way droplets of coffee often run
>>around on top of the main volume of coffee in a filter machine? 
>>                          Adrian
>
>I think this is just the effect of fairly high surface tension
>(like mercury droplets).  You also see this with ethylene glycol (antifreeze).
>
>	Jeff Mulligan (jbm@eos.arc.nasa.gov)

      Oh Boy! You have wandered into my turf. I just spent nine months
studying exactly this phenomenon (isn't physics great?). The coffee
droplets are prevented from coalescing by a thin (~1000 Angstrom) 
film of air trapped between the droplet and the surface of the
coffee. The film thins slowly, until the droplet has approached
sufficiently close to the surface for rupture to occur. Other
neat things about this phenomenon are the fact that mechanical 
vibrations increase the drop lifetime, while electric fields,
dust, and a whole bunch of other things decrease the lifetime.
In addition to coffee and ethylene glycol, you can observe this 
in just about any liquid. I have gotten droplets to last for up
to eight minutes under controlled conditions.

followups to sci.physics 
references available on request.

Andrew Case
acase@reed.edu
Newsgroups: sci.physics,soc.motss,talk.religion.misc,talk.religion.newage,alt.sex,alt.pagan,alt.atheism,alt.religion.emacs,alt.satanism
From: reb@Ingres.COM (Phydeaux)
Subject: Re: Subject?
Reply-To: reb@Ingres.COM (Phydeaux)
Organization: E 4th St Home For The Overeducated Underemployed - Chicago Div.
Date: 21 Aug 92 18:36:35 GMT

In article <FeosPB2w176w@west.darkside.com> safecrac@west.darkside.com (Chris Colvin) writes:
>Jesus Saves
...and then redeems his green-stamps for valuable cash prizes!

Newsgroups: sci.physics
From: sarfatti@well.sf.ca.us (Jack Sarfatti)
Subject: typo correct Unitarity without...
Organization: Whole Earth 'Lectronic Link
Date: Sat, 15 Aug 1992 10:05:04 GMT


Eq.13b should have a square root over the RHS
Newsgroups: sci.physics,sci.skeptic,alt.folklore.science
From: reb@Ingres.COM (Phydeaux)
Subject: Re: The dangers in microwaved food...
Reply-To: reb@Ingres.COM (Phydeaux)
Organization: E 4th St Home For The Overeducated Underemployed - Chicago Div.
Date: 19 Aug 92 20:01:40 GMT

In article <16u7u4INNpbi@agate.berkeley.edu> shirriff@sprite.berkeley.edu (Ken Shirriff) writes:
>In article <1992Aug19.134953.1500@mpifr-bonn.mpg.de> p257shu@fs1.mpifr-bonn.mpg.de (Susanne Huettemeister) writes:
>>Anyway, could someone lead us to serious reviews
>>of the health risks (or even benefits) inherent in microwaved food?
>
>There are serious health risks in eating microwaved jelly donuts.

There are serious health risks in eating un-microwaved jelly donuts.

				reb

-- *-=#= Phydeaux =#=-* reb@ingres.com  or  reb%ingres.com@lll-winken.llnl.GOV
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w:reb Ingres 10255 West Higgins Road Suite 500 Rosemont, IL 60018 708-803-9500
==============================================================================
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emulate,  know when to run.  You never count your money,  when your sittin' at 
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Newsgroups: sci.physics