HDTenEightyP/NetNews huggingface dataset:
From: dbriggs@zia.aoc.nrao.edu (Daniel Briggs)
Newsgroups: sci.chem
Subject: RFD for IMAGE PROCESSING newsgroup
Date: 13 Apr 92 18:37:21 GMT
Article-I.D.: zia.1992Apr13.183721.3713
Organization: National Radio Astronomy Observatory, Socorro NM

[Third and last time that I'm going to try and post this.  Sorry about the
multiple posts, but something in the crosspost list is buggering things!]

I just thought I'd point out that there is a discussion about an possible
image processing group over on news.groups.  I think it's a *great* idea,
and about bloody time, too.  But I seem to be surrounded by computer
vision / computer graphics people.  Could we get some scientific image
processing people over there too?  If we don't act now, we're likely to end
up with comp.graphics.image.processing, which would be a gross restriction
on an otherwise tremendously useful group.  Actually, I'd like to see a
general imaging group, not restricted to conventional image processing
techniques, but expanded to included techniques of indirect observation,
calibration and processing, as well as general imaging theory.  Say
sci.imaging.  Do we have enough support for such a group?


-- 
| Daniel Briggs  (dbriggs@nrao.edu)                      |        USPA B-14993
| New Mexico Tech / National Radio Astronomy Observatory |            DoD #387
| P.O. Box O / Socorro, NM 87801   (505) 835-7391        |
Support the League for Programming Freedom  (info from league@prep.ai.mit.edu)
Newsgroups: sci.chem
From: mcdonald@aries.scs.uiuc.edu (Doug McDonald)
Subject: Re: High vacuum questions
Organization: University of Illinois at Urbana
Date: Thu, 9 Apr 1992 14:37:04 GMT


In article <8APR92.17150106@uwpg02.uwinnipeg.ca> chem@uwpg02.uwinnipeg.ca writes:
>Hi. What are some methods used by chemists to create high vacuums?
>If a vacuum is created in a glass container, wouldn't the
>atmospheric pressure (external) smash the glass ?
>Finally, how does a vacuum pump work ? Thanks for any info. MC
>
>Internet:  CHEM@UWPG02.UWINNIPEG.CA


What a question!!!!


"Low vacuum" is created by sucking with a mechanical vacuum pump or,
amazingly enough, condensing air out in the pores of a zeolite
by cooling it with liquid nitrogen. This gets you to about 1/1000
or 1/100,000 atmosphere.

Mechanical vacuum pumps work in the obvious mechanical manners - 
various valves and pistons or rotors. The common ones work more or less
like car motors - some quite like the rotary RX7 in reverse. There are
also some that work like aquarium air pumps in reverse.

To get high vacuum (10e-9 atmosphere down to 10e-15 atmosphere) there
are many many different methods.

1) diffusion pumps -- these have a boiler which boils oil (or mercury)
   and sends it up a tube at the top of which a sort of "hat" (that
   is the technical term :-) )  turns the flow dowm. The oil molecules
   hit the air molecules and push them down and out the bottom into the
   line to the mechanical pump. The oil then hits a cold wall,
   condenses, and flows back into the boiler.


2) Turbo pumps - several fans in series, running at 40,000 to 100,000 rpm.

3) Ion pumps - powerful electric and magnetic fields create a thin plasma that
   ionizes molecules which hit walls of, usually, titanium, sputtering
   out Ti atoms, which hit the ions and eventually drive them to the walls,
   where more Ti atoms bury them. Oxygen and nitrogen and many organic
   molecules also directly react with the fresh Ti coated walls and 
   form involatile compounds.

4) Ti sublimation pumps - Ti is boiled off a filiament and works like
   the latter part of 3).

5) Cryopumps - things stick to cold surfaces, either liquid nitrogen,
   liquid helium, or a surface cooled to abouit 12K by a helium 
   refridgerator. These are helped along by using zeolites - the
   vapor pressure of something stuck in their pores is lower than that
   of the bulk material.




As to smashing glass containers, consider light bulbs or CRTs!!!
Ordinary round bottom flasks are specifically rated to take a high vacuum - 
organic chemists use them for vacuum distillations! 


Doug McDonald
From: ahahma@polaris.utu.fi (Arno Hahma)
Newsgroups: sci.chem
Subject: Re: Hydroxyl Ammonium Nitrate
Date: 9 Apr 92 08:33:25 GMT
Distribution: sci.chem
Organization: University of Turku, Finland

In article <LLEE.92Apr7171015@happy.sanders.lockheed.com> llee@rocket.sanders.lockheed.com (L. Lee) writes:

>across a compound called "Hydroxyl Ammonium Nitrate" (abbreviated as
>HAN) Does anyone have any idea what this is? I checked the standard

It is hydroxylammonium nitrate, H2N-O-NO3, a popular liquid propellant
for guns and artillery pieces. It is made by electrolytically reducing
nitric acid. This process forms hydroxylamine, which naturally reacts
with the nitric acid to form HAN. If you stop the electrolyse, when
half of the nitric acid is converted, the result will be a solution of
HAN. Another possibility is to neutralize hydroxylamine with nitric acid.

ArNO
    2
From: Gordon_Kliewer@mindlink.bc.ca (Gordon Kliewer)
Newsgroups: sci.chem
Subject: Molecular models
Date: 15 Apr 92 00:48:01 GMT
Organization: MIND LINK! - British Columbia, Canada
Distribution: world


 /ck
3-D Molecular Modeling Programs for Computer-Aided Drug
Design.

I am interested in obtaining information on 3-D Molecular
Modeling Programs.  These programs should be capable of z-
buffering, shading and x,y,z rotations.  They may be
available for both PC/Mac (low end) platforms and higher-end
workstations such as Silicon Graphics.  My particular
application for this type of program will be in computer-
aided drug design; for instance, designing enzyme
inhibitors.  I would also appreciate talking to anyone with
experience in using these programs for this purpose or any
other.  I can be reached (voice) at (604) 737-4300 in
Vancouver, B.C., Canada.  Thank you very much!
From: yan@mercury.cs.uregina.ca (Yongfei Yan)
Newsgroups: sci.chem
Subject: Re: Iron Oxide
Date: 7 Apr 92 03:25:19 GMT
Reply-To: yan@mercury.uregina.ca (Yongfei Yan)
Organization: University of Regina, Regina, Saskatchewan


Fe3O4 is actually FeO+Fe2O3, it is simply an expression for the mixture.


									John Yan
From: llee@rocket.sanders.lockheed.com (L. Lee)
Newsgroups: sci.chem
Subject: Hydroxyl Ammonium Nitrate
Date: 7 Apr 92 21:10:15 GMT
Distribution: sci.chem
Organization: Lockheed Sanders, Inc.


I was reading some articles in International Defense Review, and came
across a compound called "Hydroxyl Ammonium Nitrate" (abbreviated as
HAN) Does anyone have any idea what this is? I checked the standard
refs. like Merck's and other chemical encyclopedias and came up with
nothing. Len.
Organization: Doctoral student, Urban and Public Affairs, Carnegie Mellon, Pittsburgh, PA
Newsgroups: sci.chem
Date: Wed,  8 Apr 1992 13:49:10 -0400 
From: Lawrence Curcio <lc2b+@andrew.cmu.edu>
Subject: Re: Hydroxyl Ammonium Nitrate
Distribution: sci.chem

It's the nitrate salt of hydroxyl amine. I believe that this and
hydroxyl amine perchlorate were proposed, at one time, as replacements
for their corresponding ammonium salts in solid rocket propellants -
higher oxygen content. Don't know what happened, but I suspect the
mixtures were too sensitive. 

-Larry C.        H 
                 | +         -
             H-O-N-H      NO3
                 |
                 H
Newsgroups: sci.chem
From: jdugger@bagpipe.reed.edu (Jay Dugger)
Newsgroups: sci.chem
Subject: Starburst Dendrimers
Date: 16 Apr 92 22:04:05 GMT
Article-I.D.: reed.1992Apr16.220405.15785
Organization: Reed College, Portland, OR


	Where is work being done on starburst dendrimers?  What literature  
sources exist?  Email please.  Thanks.

	Jay Dugger
	jdugger@reed.edu
From: pellock@athena.cs.uga.edu (Rebekah Turner)
Newsgroups: sci.chem
Subject: Need info re:helium
Date: 6 Apr 92 21:25:50 GMT
Organization: University of Georgia, Athens




Hi.
Could someone please tell me who discovered helium and when?
Other pertinent info is nice but not necessary.
Thanks in advance!!

Brett
pellock@athena.cs.uga.edu
Newsgroups: sci.chem
From: gdridle@pbhya.PacBell.COM (Guy D. Ridley)
Subject: Ammonium chloride's fire resistance -- why?
Organization: Pacific * Bell
Date: Tue, 14 Apr 1992 15:06:13 GMT


My kid has this chemistry set that has lots of experiments but rarely even
attempts to explain the results.

We treated paper and cloth with an ammonium chloride solution, and just like
the book said, they were harder to set on fire (slightly), and had a greater
tendency to go out by themselves (this was the main effect.)
 
Can anyone tell me why?  Thanks...
 
Guy Ridley
pacbell!pbhya!gdridle
Organization: Penn State University
Date: Tuesday, 14 Apr 1992 16:54:37 EDT
From: <PXR5@psuvm.psu.edu>
Newsgroups: sci.chem
Subject:    MELTING POINTS CALC.INFO.WANTED

DEAR FRIENDS,
 IS THERE ANY METHOD TO CALCULATE THEORETICALLY MELTING POINT
OF SOME OXIDES? WHAT OTHER DATA ARE REQUIRED?
THANKS
RAVI
From: irikura@enh.nist.gov
Newsgroups: sci.chem
Subject: RE: High vacuum questions
Date: 11 Apr 92 05:01:34 GMT
Organization: NIST

In a previous article, chem@uwpg02.uwinnipeg.ca wrote:
>Hi. What are some methods used by chemists to create high vacuums?
>If a vacuum is created in a glass container, wouldn't the
>atmospheric pressure (external) smash the glass ?
>Finally, how does a vacuum pump work ? Thanks for any info. MC

There are many books on vacuum technology, and many companies' catalogs
also have good tuturials on how different types of pump work (e.g.,
Balzers, Leybold-Heraeus).  

Whether or not the system implodes depends on design as much as on the
material. For example, if you rest a Coke bottle sideways on its ends, you can
stand on it with no problem.  Plate glass, of course, would break immediately.
In general, it's best to avoid large, flat surfaces, since they are much weaker
than curved surfaces for a given thickness. 

Common rotary mechanical pumps (good to about 0.01 torr) work by squeezing a
slug of gas between a tightly-fitting housing an an eccentrically mounted
rotor.  Diffusion pumps reach much higher vacuum (about 10^-7 or 10^-8 torr).
They work by entraining gas in a flowing sheet of hot liquid (usually a heavy
oil, sometimes mercury).  The moving liquid carries the gas deep into the pump
where it can be removed by some other pump (called the backing pump, usually a
rotary pump).  Turbomolecular pumps are just high-speed fans that blow gases
down to a backing pump.  Turbos will get to about 10^-10 or even 10^-11 torr. 
Ion pumps are one type of getter pump. Getter pumps don't use backing pumps;
they don't actually pump the gas anywhere!  They bind gas molecules as solid
materials using various strategies.  Cryogenic pumps just freeze gases into
solid.

It's fascinating to read about the different types of pump available.  They
cover a big price range, and some can even reasonably be home-built. 

All corrections appreciated!

Karl 
Newsgroups: sci.chem
From: ah335@cleveland.Freenet.Edu (Richard Banks)
Subject: Arrhenius's definition of a base
Reply-To: ah335@cleveland.Freenet.Edu (Richard Banks)
Organization: Case Western Reserve University, Cleveland, OH (USA)
Date: Mon, 13 Apr 92 14:11:47 GMT


In my chemistry text, there are two definitions of a base given by Arrhenius.

The first one states:

- a base is any hydroxide that forms OH- ions as the only native ions when
reacted with water


The other says:

- a base is any *substance* that forms OH- ions as the only negative ions when
placed in water

Does this mean that a compound does not have to be a hydroxide to be considered
a base by arrhenius ? Or is it implying that hydroxides are the substances
that are considered base ?

Thanks
Richard Banks
Newsgroups: sci.chem
From: gjcoram@owlnet.rice.edu (Geoffrey John Coram)
Subject: Re: Buckminsterfuller (spelling?) Molecule?
Organization: Rice University
Distribution: na
Date: Wed, 15 Apr 1992 03:37:17 GMT

Newsgroups: sci.chem
Subject: Re: Buckminsterfuller (spelling?) Molecule?
Organization: Rice University
Keywords: buckyballs 

In article <kufde4INNjeo@sal-sun34.usc.edu> brockus@usc.edu (Jeffrey Brockus) writes:
>
>Does anyone know as to why this Buckminster molecule is so important?
>Is it because of its shape or its properties?

The Scientific American article is in the October 1991 issue.
Also see Popular Science from August 1991.

It is a previously unknown form of carbon.  It superconducts, it's
a semiconductor, it can do anything :)
Its shape is the reason for its peculiar stability-- why 60, not 54, 59,
etc.  (although 70, 76, 84, etc. also are more stable than their 
neighbors).
Its properties make it one of the hottest new discoveries in chemistry,
and people have all sorts of ideas about what to do with it.

Geoffrey Coram
gjcoram@owlnet.rice.edu
From: matsd@LINK.Physchem.KTH.SE (matsd@physchem.kth.se (mats dahlgren))
Newsgroups: sci.chem
Subject: Re: water + water -> hydronium + hydroxide
Date: 6 Apr 92 07:41:21 GMT
Article-I.D.: kth.1992Apr6.074121.17893
Reply-To: matsd@LINK.Physchem.KTH.SE
Organization: Royal Institute of Technology, Stockholm

In article <1992Apr5.034359.10998@usenet.ins.cwru.edu>, 
ah335@cleveland.Freenet.Edu (Richard Banks) writes:
>
>
>Does hot water have have more effective collisions because of the higher
>rate of the molecules and thus have more H O+ and OH-
>                                          3           
>molecules produced ? 
>

It is true there are more H_3O^+ and OH^- ions in hot water than in cold.  For
water at 0 degrees C, the pK_W (-lg K_W; K_W being the ionization constant for
water given by K_W = [H_3O^+][OH^-]) equals 14.94, whereas at 24 deg. C 
pK_W = 14.00 and for 60 deg. C pK_W = 13.02. [from _Handbook_of_Chem._and_
_Phys._ 60th ed., CRC Press 1980 p D-168]

>Is this why hot water is a milkier color than cold water ?
>

It is not the increase in H_3O^+ and OH^- ions which causes the milkieness of
hot water, in fact hot *pure* water is as clear as cold water.  The milkieness
seen in hot tap water is due to small bubbles of dissolved gases, i.e. air,
which are released when the pressure over the water goes down from the
tap-pressure to air-pressure.  This can be seen if you pour hot tap water into
a high glass -- after a while the water clears and there will be a sizzing
sound at the water-air interface.  (If you want to ensure the water is still hot
during the 'experiment', use a thermos.  However, the kinetics is so fast you
don't need to worry about the water in the glass cooling off.)

>Would it be less safe to drink, or do the hydronium and hydroxide ions
>still cancel each other out as they do in cold water ?
>

Hot tap water may be less good to drink.  This is not due to the H_3O^+ or OH^-
ions, but to the increased solubility of metal ions from the piping etc.  This
is of course dependent on the material used in the piping from the hot-water
tank to your tap.





mats d.


********************************************************************************

  mats dahlgren 
  Dept. of Physical Chemistry		Mail:	matsd@physchem.kth.se
  The Royal Institute of Technology	Phone:	+46 8 790 8595
  S-100 44  Stockholm, Sweden           Fax:	+46 8 790 8207

              All opinions expressed above are private opinions.
From: pravin@usenet.umr.edu (Pravin Sitaram)
Newsgroups: sci.chem
Subject: Gas chromatography
Date: 15 Apr 92 01:03:42 GMT
Distribution: usa
Organization: University of Missouri -- Rolla

Hi,

I am a graduate student studying at the University of Missouri-Rolla.

I use gas chromatographic techniques in my experiments.  I am trying to 
study the dynamics of exchange between the stearic acid on the surface
of Aluminum pigments and lauric acid in solution.  

I am having problems with the reproducibility of my data.  In order to study 
the fatty acids viz., stearic and lauric acid on the gas chromatograph, I am
using a derivatizing agent to convert it to the methyl ester.  

The question I had is "Does derivatization affect reproducibility?"  If it 
does what could be the possible ways I can get over this problem.  

Please email your answers directly to me,

My email address is pravin@clciris.chem.umr.edu

Thanks in advance

Pravin
 
Newsgroups: sci.chem
From: gay@selkirk.sfu.ca (Ian D. Gay)
Subject: Re: Iron Oxide
Organization: Simon Fraser University, Burnaby, B.C., Canada
Date: Sun, 5 Apr 1992 17:45:41 GMT

ah335@cleveland.Freenet.Edu (Richard Banks) writes:


>I know of Iron oxide whose formula is Fe O
>                                        2 3
>Fe (II) with a positive charge of 3+

That's Fe(III)

>O (oxide) with a negative charge of 2-

>But I saw another formula for Iron oxide that was Fe O
>                                                    3 4

>I've never seen this one before or it's separate ions, can someone please
>help me understand this one.

All of the O is 2-. With the 4O (8- total) you have two Fe(III) and 
one Fe(II), adding up to 8+ total. This kind of mixed valence oxide is 
fairly common (eg Mn3O4, Co3O4, U3O8 ....).
From: uncacj@ecsvax.uncecs.edu (Charles G. James Jr.)
Newsgroups: sci.chem
Subject: Re: Arrhenius's definition of a base
Summary: Other bases
Date: 16 Apr 92 15:49:00 GMT
Organization: UNC Educational Computing Service

In article <1992Apr13.141147.26709@usenet.ins.cwru.edu>, ah335@cleveland.Freenet.Edu (Richard Banks) writes:
> 
> - a base is any *substance* that forms OH- ions as the only negative ions when
> placed in water
> 
> Does this mean that a compound does not have to be a hydroxide to be considered
> a base by arrhenius ? Or is it implying that hydroxides are the substances
> that are considered base ?


Examples of bases from VanderWerf "Acids, Bases and the Chemistry of
the Covalent bond"1965 are:
	Sodium hydride NaH
	Sodium amide NaNH2
	etc.
These compounds in water:
	NaH -> Na+  +  H-
then
	H-  +  H2O  ->  H2  + OH-

They did not start out with a hydroxide but they do produce them in water
The strongest base that can exist in a water solution is therefore the OH-
-- 
Charles G. James, Jr.
Department of Chemistry, University of North Carolina at Asheville
Asheville NC 28804-3299
BitITNET: uncacj@ecsvax    or OR    james@unca.bitnet
From: chem@uwpg02.uwinnipeg.ca
Newsgroups: sci.chem
Subject: Mirja Karjaanen (Finland) e-mail address?
Date: 11 Apr 92 03:11:12 GMT
Organization: University of Winnipeg

Would anyone know the email address of the Finnish chemist
Mirja Karjaanen (sp?). Thanx, M. Carroll
Internet:  CHEM@UWPG02.UWINNIPEG.CA
Newsgroups: sci.chem
From: gjcoram@owlnet.rice.edu (Geoffrey John Coram)
Subject: Re: Buckminsterfuller (spelling?) Molecule?
Keywords: buckyballs 
Organization: Rice University
Date: Wed, 15 Apr 1992 03:31:53 GMT

In article <kufde4INNjeo@sal-sun34.usc.edu> brockus@usc.edu (Jeffrey Brockus) writes:
>
>Does anyone know as to why this Buckminster molecule is so important?
>Is it because of its shape or its properties?

The Scientific American article is in the October 1991 issue.
Also see Popular Science from August 1991.

It is a previously unknown form of carbon.  It superconducts, it's
a semiconductor, it can do anything :)
Its shape is the reason for its peculiar stability-- why 60, not 54, 59,
etc.  (although 70, 76, 84, etc. also are more stable than their 
neighbors).
Its properties make it one of the hottest new discoveries in chemistry,
and people have all sorts of ideas about what to do with it.

Geoffrey Coram
gjcoram@owlnet.rice.edu
Organization: Johannes Kepler University Linz - Computing Center
Date: Tuesday, 7 Apr 1992 17:25:33 CDT
From: Norbert Mueller <K360171@ALIJKU11.BITNET>
Newsgroups: sci.chem
Subject: Buckyball coords

I am looking for coordinates of buckminsterfullerene for use
in a computer aided chemistry course, our current installation
of the Cambridge Crystallography Datafile does not have it.
Can somebody help.

Thanks

N. Mueller, Inst. of Chemitry, Johannes Kepler University, Linz Austria
From: rluoma@hila.hut.fi (Rauno Luoma)
Newsgroups: sci.chem
Subject: Lead in water Re: water + water -> hydronium + hydroxide
Date: 8 Apr 92 08:50:42 GMT
Organization: Helsinki University of Technology, Finland

In article <1992Apr7.011202.22707@athena.mit.edu> sybok@m4-035-4.MIT.EDU (The Terminator) writes:
>>If this is so, is it the reason we should use cold water for cooking and eating
>>as opposed to hot?  Do the excess hydroxide ions bond more easily with the lead


>It's simply that the solubility of lead in water is a function of temperature.
>As the temperature of the water is raised, lead becomes more soluble
>in water 

I think that lead chloride is more important in that case. It solubility
in hot water is much larger than in cold water and there is always
chloride-ions in water.




Rauno Luoma                                phone +358-0-4512778
M.Sc                                       internet Rauno.Luoma@hut.fi
Helsinki University of Technology
Laboratory of Metallurgy                   home  +358-0-822426
From: carlj@hpcvmcdj.cv.hp.com (Carl Johnson)
Date: Mon, 6 Apr 1992 19:08:12 GMT
Subject: Re: Dissolving Epoxy
Organization: HP Corvallis, Oregon
Newsgroups: sci.chem

In sci.chem, sakari@laureline.cs.hut.fi (Sakari Aaltonen) writes:

> I have a small collection of dynamic RAMs, that is, memory chips, that could
> perhaps be used as optical detectors - they are out-of-date for computer
> purposes.
> The problem is that the chips are packaged in plastic which would have to
> be removed in order to expose the chips themselves to light. 
> Does anyone know of a chemical substance that would dissolve the plastic?
> Mechanical methods do not seem to work.
> --

I have seen chips that have been 'decapped' for examination, but I
believe the process that is usually used is to drip hot fuming nitric
acid on it.  The chips I have seen processed have had a circular
'crater' etched down to the chip.  I think the other areas of the part
are protected with something like paraffin wax.  Obviously this will
need to be done carefully and under a fume hood.  Anybody from an IC fab
facility know how this is done?

> -----------------------------------------------------------------------------
> Sakari Aaltonen                             Helsinki University of Technology
> Email: sakari@cs.hut.fi
> ---  You can't keep a Finn down without him getting all red in the face  ----

Carl Johnson              carlj@cv.hp.com