HDTenEightyP/NetNews huggingface dataset:
From: paul@gaitlab1.waterloo.edu (paul j guy)
Subject: Re: Dissolving Epoxy
Summary: using chloroform
Keywords: epoxy,solvents
Organization: University of Waterloo, Waterloo,Ontario
Date: Wed, 8 Apr 1992 02:38:40 GMT

  One of my favourite but very slow ways to get epoxy off electronic
components is to either bathe them in choroform or methylene chloride
for a few days. The epoxy becomes 'granular' and can be picked off.
  The vapours work just as well, maybe a little slower. For this 
technique you put some of the solvent in a jar, and raise the parts above
the liquid level. After a few days the epoxy will deteriorate enough to
enable one to get at the parts that used to be potted. This will not
attack the conductors, but will remove colour codes, and the normal
component protective coatings.
  I have never done this to an IC, so I can't tell you how effectively it
removes the epoxy coating.
  Anything that has nitric or strong acids as a remover (as indicated by
some of the earlier postings) will certainly obliterate any of the
fine wires exposed in an IC.
  The chloroform trick works well for removing strain gauge elements so
that they may be re-used. One has to be incredibly cheap to resort to such
a thing.

-- 
-----------------------------------------------------------------------------
Paul J Guy			work phone:519-885-1211 ext 6371  
paul@gaitlab1.waterloo.edu	home/FAX/message:519-576-3090
pguy@watkin3.waterloo.edu	..remember...bullshit baffles brains...
Newsgroups: sci.chem
From: tbwhite@watmath.waterloo.edu (Thomas B White)
Subject: Information Request
Organization: University of Waterloo
Date: Wed, 8 Apr 1992 14:57:59 GMT

    Hello.  I am posting this for a friend of mine who is in third year
Biochemistry at the University of Waterloo.  Please excuse any terminology
mistakes I make in this posting, as I am sadly ignorant of most things
pertaining to the science of chemistry...

    My friend is hoping to write a paper on a recently discovered molecule,
apparently given the name "Buckminster Fullerene", or C  .  He has checked
						       60
the local libraries, but the subject is so new that there is little or
nothing to be found.

    If any kind person has any information relating to this molecule,
could they please reply to this article either by posting to this group
or by email to the address below?  Thanks very much!

Thomas B White
Computer Science/University of Waterloo
tbwhite@watmath.waterloo.edu
Newsgroups: sci.chem
From: sybok@m4-035-4.MIT.EDU (The Terminator)
Subject: Re: water + water -> hydronium + hydroxide
Organization: Massachusetts Institute of Technology
Date: Tue, 7 Apr 1992 01:12:02 GMT

>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
>in lead pipes and pull it into solution - or does the problem with lead in 
>water stem from the fact that it may come out of an old water heater which may 
>contain some 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 and Le Chatlier's Principle dictates that more lead will enter
the water as solute.
Newsgroups: sci.chem
From: mvp@hsv3.uucp (Mike Van Pelt)
Subject: Re: Dissolving Epoxy
Organization: Video 7 + G2 = Headland Technology
Date: Wed, 8 Apr 1992 00:46:43 GMT

I *think* I remember hearing somewhere that DMSO dissolves epoxy, but
I am not at all sure of this.  Be careful with DMSO; it's not too toxic
itself, but it penetrates the skin, and takes with it anything that
happens to be dissolved in it.
-- 
Mike Van Pelt            Paradimethylaminobenzaldehyde,
Headland Technology      Go soak your head in a good strong insecticide,
mvp@hsv3.lsil.com        Slosh it around and impregnate your brain
...ames!vsi1!hsv3!mvp    With dichlordiphenyltrichloroethane.
From: ssouth@hpldsla.sid.hp.com (Steve South)
Date: Tue, 14 Apr 1992 23:36:21 GMT
Subject: Re: Re: LCD lifespan
Organization: HP Scientific Instruments Division - Palo Alto, CA
Newsgroups: sci.chem

Hmmm,

It's a long time ago, but I used to work in the analytical department of
a British company that was at one time the worlds largest supplier of
liquid crystal materials.

The materials were cyano-alkyl-biphenyls, cyano-alkoxy-biphenyls, and cyano-
alkyl-terphenyls. Generally a eutectic mixture was sold which gave the largest
nematic range. As far as I can remember, the materials were pretty stable. One
restriction was that there be no DC component applied across the cell. Some
lower quality materials from other suppliers tended to have some problems with
stability I think. One interesting problem that some early displays had was 
that of reverse twist. This was overcome on our materials by adding an optically
active component. 

The other problem, which gave me no end of grief, was that of amide. The cyano-
alkyl-[bi-/ter-]phenyls were prepared in several stages, starting with
4-bromo-biphenyl. First a Friedel-Crafts acylation, followed by a reduction,
followed by a cyanation. Each stage was purified prior to proceeding. The 
problem arose at the cyanation where some amide was produced. This could reduce
the life of a display, I was told.

I did the gas-chromatographic analysis of the LC's (this was before capillary
columns were widespread) with a Pye 104, FID and a Kent Chromalog 'Integrator'.
This hideous thing had vacuum tubes and you had to manually start and stop it
at the beginning and end of each peak. The column I used was a 5' 3% OV225
on GasChrom Q (God, it seems like yesterday!) and with a maximum operating
temperature of about 250C there were some long retention times. In particular,
for the highest MW material, the main product had a retention time of about
10 minutes, and the amide had an RT of something like an hour. So I would
be there to integrate the first peaks, go for lunch, and then come back to 
integrate the amide peak (if any). Trouble was, I didn't always get back from
lunch in time.....

If only they hadn't been such a bunch of cheapskates they would have bought
decent HP GC's and integrators :-)

So, (after the irrelevancies above) I can't give you any real numbers for
LCD lifetimes, but provided the electrical rules are applied you shouldn't
have much of a problem.

To the chemists out there, my apologies for any technical/spelling errors. It
was a long time ago.

Steve South.
------------

ObChem: Old chromatographers never die - they just enter a stationary phase.
From: tomas_e@LINK.Physchem.KTH.SE (Tomas Eriksson)
Newsgroups: sci.chem
Subject: Re: water + water -> hydronium + hydroxide
Date: 6 Apr 92 11:16:25 GMT
Reply-To: tomas_e@LINK.Physchem.KTH.SE
Organization: Royal Institute of Technology, Stockholm

In article <1992Apr6.074121.17893@kth.se>, matsd@LINK.Physchem.KTH.SE
(matsd@physchem.kth.se (mats dahlgren)) writes:
>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.)

The reason these bubbles aren't seen in cold water is that the 
solubilities of gases in water generally decrease as the temperature 
goes up. You see this when you boil water; the first bubbles you get, at 
< 100 deg. C, are "air" (*) and not water vapour.

And there is no reason to worry about the H_3O^+ and OH^- ions not 
cancelling each other. They do of course originate from H_2O, which 
ensures that they are produced in equal amount.

(*) different gases have different solubilities, so this "air" has 
different amounts of various gases than "real air" has.

Tomas
-------------------------------------------------------------------------------
Tomas Eriksson         tomas_e@physchem.kth.se         (ter110@phys.anu.edu.au)
            Surface Force Group, Department of Physical Chemistry,
               Royal Institute of Technology, Stockholm, Sweden
From: shaw@s119.es.llnl.gov (Henry Shaw 510 423-4645)
Newsgroups: sci.chem
Subject: Re: Iron Oxide
Date: 7 Apr 92 23:05:38 GMT
Organization: Earth_Sciences_Dept.,_LLNL

In article <1992Apr7.032519.2894@regina.cs.uregina.ca>, writes:
|> 
|> Fe3O4 is actually FeO+Fe2O3, it is simply an expression for the mixture.
|> 
|> 
|> 									John Yan


It ain't a mixture.  Fe3O4 is a compound that goes by the name of magnetite (e.g. "lodestone").
It is an example of one of many such mixed-valence oxides.  It`s a member of the spinel 
group of minerals, which all have general formula AB3O4, where the A cation is tetrahedrally 
cordinated by the oxygen atoms, and the B cation is octahedrally coordinated.  "Normal" spinels
have the the cation with +2 formal valence in the tetrahedral position and the +3 valence 
cations in the octahedral position.  Magnetite is an example of an "inverse spinel", which have
the divalent cation in octahedral sites.  a "structural formula" for magnetite could thus be 
written: Fe+3(Fe+2 Fe+3)O4.

-- 
Henry Shaw, Earth Sciences Dept., LLNL |    All opinions are my own.
Internet: shaw4@llnl.gov               |  
CIS: 76347,2523                        |
Fidonet: Henry Shaw at 1:161/55        |
From: tmiyazak@etl.go.jp (Takehide Miyazaki)
Newsgroups: sci.chem
Subject: IUPAP Conf.
Date: 11 Apr 92 19:08:40 GMT
Organization: Electrotechnical Laboratory, Tsukuba Science City


     Does anybody know ANY information on " 6-th International
Symposium on Small Particles and Inorganic Clusters ", which will
be held in Chicago, Sept. 16-22, 1992 ? 

Especially I would like to know session topics, dead line for papers and
important addresses. 

I have posted the same question to sci.materials, but I have
got no reply yet. 

     Thank you very much in advance. 

     Takehide Miyazaki , Electrotechnical Laboratory
     e-mail: tmiyazak@etl.go.jp
From: bg055@cleveland.Freenet.Edu (Stewart Rowe)
Newsgroups: sci.chem
Subject: Re: Information Request
Date: 8 Apr 92 23:57:07 GMT
Article-I.D.: usenet.1992Apr8.235707.4440
Organization: Case Western Reserve University, Cleveland, Ohio, (USA)


(Information on Buckyballs?)
Try Scientific American for the last couple of years --  their 
'popular' articles usually give technical journal references.
Also _Science_ which has an annual index.
Newsgroups: sci.chem
From: routd@woods.ulowell.edu
Subject: CALL FOR A NEWS GROUP on LIQUID CRYSTAL TECHNOLOGY.
Organization: University of Lowell
Date: Fri, 17 Apr 1992 17:39:30 GMT

CALL FOR A SCI. GROUP ON LIQUID CRYSTAL TECHNOLOGY.
--------------------------------------------------

Dear netters,

	Liquid Crystals are becoming a major part of our daily lives. Your
watch may have a LCD. Your Car might be having a couple of them! Are not 
they look sleek! If you are not a worker in this area, you might not have
a chance to look at them more closely. If you see Liquid crystals under a 
polarizing microscope, you probably would think,"I have never seen more beautiful
things in life!"
	Liquid crystals, though discovered by a botanist a century ago, only 
became very active by the 1950-60s.This field underwent a sea change in the
later half of this century! First fabrication of LCDs were around 1960-70. 
Discovery of Ferroelectrics, Polymeric Liquid crystals, attracted a lot of
attention to this feild!

	It becomes a meeting ground of so many Physical, chemical and biological
phenomena now. To name a few, There has been similarity in High Tc superconducti
vity and Twist grain boundary phase of smectic phase. Formation of galaxies can be
be understood from temporal observation of liquid crystal defects. etc. DNA
is found to have LC phases!The list is endless...................

	The purpose of this group would be to discuss and solve problems relating
to liquid crystals, new developments, new products, crazy but true ideas etc....

	I have already posted similar requests in the SCI.engr. and SCI.physics
news groups. The response so far has been good, though not terrific. Expectinng
a few more votes and suggestions in this regard.

	Thanx in advance.

	Deeleep K. Rout
==================================================================================
Dept. of Chemistry
U Mass. Lowell
MA 01854

(508)-934-3712 (Lab.)
routd@woods.ulowell.edu
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 


Xref: sparky sci.chem:1888 sci.materials:229 sci.optics:483
Newsgroups: sci.chem,sci.materials,sci.optics
Subject: Ellipsometry Program
From: pollack@ucunix.san.uc.edu (Steven Pollack)
Date: Thu, 9 Apr 92 18:03:49 GMT
Organization: University of Cincinnati

Does anyone out there have a copy of McCracken's (spelling) program for
ana;lysis of ellipsometry data that I can download or that you can
e-mail to me.  Our version here is on punch card and it would be much
more painless to get it onto out machine via this medium.


_______________________________________________________________________
Steven K. Pollack               |
University of Cincinnati        |
Department of Materials Science |   I notice that you are still
  & Engineering                 |   using polymers!
498 Rhodes Hall  ML#12          |     - Lt. Commander Montgomery Scott
Cincinnati, OH 45221-0012       |       U.S.S. Enterprise
pollack@ucunix.san.uc.edu       |
________________________________________________________________________


Newsgroups: sci.chem
From: nasadk@aix.rpi.edu (Kristopher Martin Nasadowski)
Subject: Re: Buckminsterfuller (spelling?) Molecule?
Distribution: na
Date: Sun, 12 Apr 1992 18:02:24 GMT

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?

Umm. Buckminsterfullerene (sp?) or Buckyballs, have become a sort
of new 'toy' to play with. First of all, Carbon is known to exist as
graphite in a planar form, and diamond in a networked solid (i think) form.
Both forms are all carbon atoms, its the arrangement that differs. Now, in
1985, a new structure of carbon was discovered. Made up of hexagons and 
pentagons, it is similar in structure to Buckminster Fuller's geodesic domes,
hence the name.

If you want to read an article, Scientific American did one in the last
year, I think either April or January 1991, but I'm not sure.

Incidentally, the shape is of a 60 Carbon ball, much like the pattern
on a soccer ball.

I can't reaslly tell you too much more, but almost any scientific journal
relatying to chemistry most likely has carried an article on bucky balls 
in the past year.

Nazman
<nasadk@rpi.edu>
From: derek@lynx.cs.wisc.edu (Derek Zahn)
Newsgroups: sci.chem
Subject: mail-order chemicals?
Date: 10 Apr 92 17:32:48 GMT
Organization: University of Wisconsin, Madison -- Computer Sciences Dept.

A Question for the chemically-inclined:

Does anybody have addresses for places that sell small quantities
of "common" chemicals through the mail?  I would like to amuse
myself and some other small children (:-)) with a few reactions
and so on, which will encourage me to re-learn all the chemistry
that I've managed to forget in the last few years.

But, I don't want industrial-sized vats of the stuff; little bottles
are all that I need.  Any clues of places that would send me
a catalog?

Thanks!

derek
From: fayala@mtecv2.mty.itesm.mx
Newsgroups: sci.chem
Subject: Chemical senses
Date: 8 Apr 92 02:22:17 GMT
Reply-To: fayala@mtecv2.mty.itesm.mx
Distribution: alt

I need information about smell and taste evaluation and its relationship with pollution.
From: hlw@rti.rti.org
Newsgroups: sci.chem
Subject: INFO NEEDED:  GC/MS FTP/network access?
Keywords: gas chrom, GC, mass spec, MS, FTP, network, access
Date: 6 Apr 92 12:41:51 GMT
Organization: Research Triangle Institute, RTP, NC

Are there archives available via FTP/network access for Mass Spectra
or Gas Chrom. of chemicals?  

If so, how are they indexed?

If not, what would you recommend as "the next best thing"?

Any and all help is greatly appreciated!
Hal Waters
(hlw@rti.rti.org)

-- 
********************************************************************************
* Hal Waters   Center for Digital Systems Research    ARPANET: hlw@rti.rti.org *
*  (IXOYS!)    Research Triangle Institute, RTP, NC   USENET:     mcnc!rti!hlw *
********************************************************************************
From: v136pds9@ubvmsb.cc.buffalo.edu
Newsgroups: sci.chem
Subject: integration help
Date: 16 Apr 92 15:01:00 GMT
Organization: University at Buffalo
News-Software: VAX/VMS VNEWS 1.41


Could someone help with an integral that I am trying to solve?


	I have to integrate the following from -pi to pi


	exp(-B*f{x})   dx


	where B is a constant (Beta = kT)

	and

		f{x} = a + b*cos(x) + c*cos^2(x) + d*cos^3x) + e*cos^4(x)
	
		x=theta
THANKS
From: apl@st-andrews.ac.uk (Andrew P Leech)
Newsgroups: sci.chem
Subject: Re: Dissolving Epoxy - A SUMMARY
Summary: Be careful with HNO3
Date: 7 Apr 92 18:39:27 GMT
Organization: St. Andrews University, Scotland.

On exposing DIPs...


>A WORKABLE METHOD (I hope)
>
>Fuming nitric acid and sulfuric acid were recommended by several people.
>The rub is that not all of the plastic should be dissolved; if it is, things
>collapse (the plastic is what holds the chip, the bonding wires and the pins
>together).
>The following method, suggested by Wayne Covington (wayne@hpfcso.fc.hp.com)
>and Richard Thornton (see above) appears workable:
>  1. machine/drill/grind a depression on top of the package (where? Wayne
>     Covington X-rays the DIP; I hope "the middle" is close enough); do not
>     go through the plastic
>  2. put a small amount of nitric acid (HNO3, I think) in the depression,
>     wait, wash with acetone
>  3. do 2. again until the chip is exposed
>Wayne Covington didn't mention the temperature of the acid, but I think it
>must be hot. In fact, I already tried nitric acid at ambient temperature;
>nothing happened.
>Richard Thornton puts the DIP on a hotplate and washes it when the acid
>in the hole bubbles. Note that this gives a limit on how long to wait in
>step 2.
>How hot? Probably the hotter, the faster. I looked in the data sheets of
>various DRAMs under Absolute Maximum Ratings, Storage Temperature. The
>maximum appears to be 125C.

>successful, I regret to say that I'll probably go off the net soon (the


If you're not careful you could go "off the net" permanently. Mixtures of
nitric acid and acetone are liable to explode - after an indeterminate
induction period!
Even worse, the fumes produced from nitric acid/organic mixtures are
extremely toxic (NO2). From a safety data sheet:
"Symptoms... include coughing and burning in the throat and chest. On
removal to fresh air the symptoms may disappear. However between 6 and
24 hours after exposure there may be sensations of tightness and burning
in the chest, shortness of breath and restlessness. This could progress
to cyanosis and loss of consciousness which could be followed by death"

If you must use nitric acid, DO YOUR EXPERIMENTS IN AN EFFICIENT FUME
HOOD and WASH EVERYTHING WELL WITH WATER afterwards.

If you need the chip to work after opening, acid is a bad idea anyway
as silicon is relatively easily oxidised.
I think a better, if duller, method would be to bend the DIP's legs out
of the way, clamp it in a vice, and attack it with a rasp or file.

********************************************************************************
Andrew Leech                |DOS...  was naught,  only a little copy, a child's
Mail to: apl@uk.ac.st-and   |model or a slave's flattery, of that vast fortress,
Telephone: 0334 76161 x 8379|armoury,  prison,  furnace of great power  ...Unix
********************************************************************************
Newsgroups: sci.chem
From: dzk@cs.brown.edu (Danny Keren)
Subject: A Question About Hydrocyanic Compounds
Organization: Brown University Department of Computer Science
Date: Mon, 6 Apr 1992 21:38:49 GMT

I would be grateful for an answer to the following question regarding
HCN (hydrocyanic acid), and/or references in the literature:

If building materials (concrete for instance) are exposed to HCN,
cyanic compounds (called "prussian blue") are formed. Assuming an
equal time of exposure, is there a difference between the amount
of compounds formed in the case of one long exposure versus
several short exposures? Explicitly, suppose one exposure taking
300 minutes, or 20 exposures taking 15 minutes each (seperated by
one day) for the same concentration of HCN. Will there be a 
difference in the amount of "prussian blue" generated?

Thanks,

-Danny Keren.
From: irikura@enh.nist.gov
Newsgroups: sci.chem
Subject: RE: Mask recommendation wanted
Date: 5 Apr 92 15:39:03 GMT
Organization: NIST

I had some trouble with American Chemical Society periodicals (esp. Chem.
Abstracts) for a couple of years after they changed inks (symptoms like bad hay
fever).  Fortunately, the problem disappeared.  I did write to a journal editor
at one point, however, and he suggested that I consider microfiche
subscriptions.  Although microfiche is not as handy as regular printed
journals, it might be more convenient (or more comfortable) than wearing a big
mask or putting your journals in a glove box.  Another advantage might be that
microfiche takes up MUCH less space than paper. 

If more people with sensitivity problems write, the publishers may realize how
severe the problem is. 

Good luck, 
Karl Irikura 
irikura@enh.nist.gov 
Newsgroups: sci.chem
From: lorenzo@hsi.com (Evelyn Lorenzo)
Subject: Re: water + water -> hydronium + hydroxide
Reply-To: lorenzo@hsi.hsi.com.com (Evelyn Lorenzo)
Organization: 3M Health Information Systems, Wallingford
Date: Mon, 6 Apr 1992 17:37:32 GMT

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

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
in lead pipes and pull it into solution - or does the problem with lead in 
water stem from the fact that it may come out of an old water heater which may 
contain some lead?  


Evelyn Lorenzo