HDTenEightyP/NetNews huggingface dataset:
From: sakari@laureline.cs.hut.fi (Sakari Aaltonen)
Newsgroups: sci.chem
Subject: Re: Dissolving Epoxy - A SUMMARY
Date: 7 Apr 92 07:22:47 GMT
Reply-To: sakari@niksula.hut.fi (Sakari Aaltonen)
Organization: Helsinki University of Technology, Finland


A summary of responses to my query
     Dissolving Epoxy                (sci.chem)
     Taking the Lid off Plastic DIPs (sci.electronics)


A DANGEROUS METHOD

Bruce Hamilton (SRGBXHH@grv.dsir.govt.nz) reported having found DMF
(Dimethylformamide) an easy-to-use, though slow, solvent for epoxy (NB: at
ambient temperature). He warned that DMF is dangerous.
Pat Wilcox (wilcox@cis.ohio-state.edu) reinforced the warning.
I believe them. I don't have DMF available, anyhow.


EXPENSIVE METHODS

r.thornton@trl.oz.au (Richard Thornton) mentions the use of a controlled
sulfuric acid jet.
A local Master's Thesis I was directed to after posting my query (didn't do
my homework, did I?) describes using a plasma etcher.


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.



THANK YOU ALL

I shall try the above method. If anyone is interested in whether it proves
successful, I regret to say that I'll probably go off the net soon (the
school's budget demands this). Truly it is as the man said: it's a privilege,
not a right.
--
-----------------------------------------------------------------------------
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  ----
From: James_J_Kowalczyk@cup.portal.com
Newsgroups: sci.chem
Subject: Re: Information Request
Date: Wed,  8 Apr 92 19:30:13 PDT
Organization: The Portal System (TM)

Regarding the request for information of Buckminsterfullerene (C60),
the current issue of Accounts of Chemical Research (issue 3, March, 1992)
is devoted exclusively to this topic. (Sorry, I don't have it with me,
so I don't know the volume).  This is an ACS journal.

Jim Kowalczyk
Eisai Research Institute
Andover, MA  01810

James_J_Kowalczyk@cup.portal.com
From: chem@uwpg02.uwinnipeg.ca
Newsgroups: sci.chem
Subject: For boron@violet.berkeley.edu
Date: 3 Apr 92 18:33:23 GMT
Organization: University of Winnipeg

Hi. Sorry I have to post this to the whole list, but
technical reasons are the reason....
Howdy SL. Please send the Mac molar mass programs
(binhexed) to me. Thanks, Marsh

Internet:  CHEM@UWPG02.UWINNIPEG.CA
Newsgroups: sci.chem,sci.bio
From: cheeze@next02wor.wam.umd.edu (Joshbo )
Subject: Re: LCD lifespan
Organization: Workstations at Maryland, University of Maryland, College Park
Distribution: na
Date: Sun, 12 Apr 1992 23:52:41 GMT

 I previously posted an article in sci.electronics concerning the lifespan
 of a typical (high quality) watch LCD display.  The answers were  
unsatisfactory to me, so I'll try to ask a different crowd ...
     Given normal use and normal environmental conditions (which, for my
 purposes means temperatures between zero and 30 degress centigrade), how
 long will an LCD unit continue to function without fading or failing
 altogether.  I understand that the organic crystals that make up the
 guts of the LCD do not generally react unless exposed to air.  And so,
 if the seal between the two glass sheets remains, the LCD should continue
 to function, at least in theory, for a "lifetime" (>50 years).  Do the
 seals on these LCD units hold up over time (are there any specs on this)?
 And, if not a "lifetime", what is the average estimated lifespan of the 
 LCD unit?  And one more question:  What other age limitations might
 exist in the components of the typical, high quality LCD watch?  For
 example, do the piezo-quartz crystals fail; do the diodes fail; do the
 capacitor(s) fail?  (I know nothing lasts forever, but does anything last
 close to forever? (: ) 
      Sorry for all the bizarre questions.  Any help is appreciated.
 
                                 -- Joshua Bloomberg
                                    Cheeze@wam.umd.edu
From: jgd@dixie.com (John De Armond)
Newsgroups: sci.chem
Subject: Metal plating questions
Date: 8 Apr 92 05:17:09 GMT
Organization: Dixie Communications Public Access.  The Mouth of the South.

I am setting up some small scale plating lines and need some advice and
pointers.  The metals of interest are currently nickel and copper with
silver coming later.  The base metal is primarily lead/solder.  Volume
is in the dozens of pieces a week.

I'm looking for advice or pointers to literature regarding procedures, bath
composition, voltage and current density and so on.  I currently have the 
copper line operating using an acidified saturated solution of copper
sulfate.  This was set up from ancient memory.  Voltage is 3 volts.
Current for a typical small (~5 square inches) is on the order of an
amp.  I have spent considerable time in trial and error optimizing
the parameters for best brightness and adhesion but lacking information
on what parameters affect what, I've reached my limit.

Any information would be appreciated.  Email please, as this newsfeed
is erratic at the moment.

Thanks,
John
-- 
John De Armond, WD4OQC        | What's the difference between Jane Fonda
Rapid Deployment System, Inc. | and Bill Clinton?  Hanoi Jane went to 
Marietta, Ga                  | Viet Nam.              
jgd@dixie.com                 | Need public access in Atl?  Write me.
Newsgroups: sci.chem
From: mroussel@alchemy.chem.utoronto.ca (Marc Roussel)
Subject: Re: High vacuum questions
Organization: Department of Chemistry, University of Toronto
Date: Thu, 9 Apr 1992 16:41:26 GMT

In article <8APR92.17150106@uwpg02.uwinnipeg.ca> chem@uwpg02.uwinnipeg.ca writes
>What are some methods used by chemists to create high vacuums?

     The usual method for creating high vacuums is to pump the system
to the lowest possible pressure using a mechanical pump and then to use
a diffusion pump to take the pressure down the rest of the way.
Synthetic work thankfully doesn't normally require anything more than
can be achieved with a mechanical pump.

>If a vacuum is created in a glass container, wouldn't the
>atmospheric pressure (external) smash the glass ?

     Glass is actually quite a strong substance.  Ordinary chemical
glassware is quite adequate for most vacuum work.  The only thing of
which one must beware is cracks; one simply can't have them in any
glassware which will be submitted to a vacuum.  Obviously though some
combinations of heating or cooling and low pressure require special
containers; I plead ignorance of the details here.

				Marc R. Roussel
                                mroussel@alchemy.chem.utoronto.ca
From: whitbeck@equinox.unr.edu (Michael Whitbeck)
Newsgroups: sci.chem
Subject: Re: Red-tinted volumetric flasks
Date: 14 Apr 92 23:16:34 GMT
Organization: University of Nevada, Reno

In article <1992Apr13.214927.4905@udel.edu> lim@toffee.udel.edu (Julie Lim) writes:
]>
]>	Does anyone know when red-tinted vol flasks came into commercial
]>distribution? I've been plowing through old chem-supplyh catalogs in the
]>UDel library, but there's a long gap between 1907 and 1961. (In)Conveniently
]>enough, red vol flasks are in the 1961 catalog, which means that they came
]>into use/production sometime in those 54 years. Postive examples would be
]>more useful than negative ones; Aldrich, for example, didn't stock red vol
]>flask-- or any volumetric ware at all-- until their 1986-1987 catalog.6-1987 catalog.6-1987 catalog.6-1987 catalog.6-1987 catalog.6-1987 catalog.
]>	Also, what provides the tint-- and why red? Most catalog listing 
]>describe the red flasks as "low-actinic"-- does this describe the tint, or
]>some other property? And why not blue or green or brown?
]>
]>
]>
]>
]>
]>-- 
]>MUDname: Sidera           "...If I seem to give a damn, please tell me. I would
]>University of Delaware      hate to be giving the wrong impression."
]
]

"actinic" refers to sensitivity to radiation- in this case light
(electromagnetic radiation) The red flasks are used when working
with light sensitive compounds/solutions. 

Why red? I suppose because of the historic use of Ag halide in 
photoemulsions (photo safety-lights/for B&W photography are
often dark red (but sometimes dark-dark green)). Photons from the
red end of the spectrum have lower energy (Planck's law) and
hence are less likely to break chemical bonds. 

There are however red sensitive photochemical reactions:
photohydrolysis of some Cr complexes
photodissociation of some C-nitroso compounds
.... more than you wanted to know.


I would look in the journal lit for old photochem citations to
find the earliest record of red flasks.
[I'm not sure but the red may be finely dispersed gold
particles]

___________________________________________________________
|Mike Whitbeck             | whitbeck@equinox.unr.edu     |
|Desert Research Inst.     | whitbeck@wrc.unr.edu         |
|POB 60220                 |                              |
|RENO, NV 89506            | 702-673-7348                 |
|__________________________|______________________________|

All academics have the potential for being insatiable...
but the chemists are the most expensive and insatiable among the
expensive and insatiable. - J. Martin in "To Rise Above Principle"
From: chappell@mercury.stat.wisc.edu (Rick Chappell)
Newsgroups: sci.chem
Subject: Re: Dissolving Epoxy
Date: 6 Apr 92 14:52:21 GMT
Organization: Dept. of Statistics, Univ. of Wisconsin

Acetone softens uncured epoxy (at least several commercial brands
thereof), but does not detectably affect the cured stuff, by my
untutored observation.

Rick Chappell.
Newsgroups: sci.chem
From: lim@toffee.udel.edu (Julie Lim)
Subject: Red-tinted volumetric flasks
Organization: University of Delaware, Newark
Date: Mon, 13 Apr 1992 21:49:27 GMT


	Does anyone know when red-tinted vol flasks came into commercial
distribution? I've been plowing through old chem-supplyh catalogs in the
UDel library, but there's a long gap between 1907 and 1961. (In)Conveniently
enough, red vol flasks are in the 1961 catalog, which means that they came
into use/production sometime in those 54 years. Postive examples would be
more useful than negative ones; Aldrich, for example, didn't stock red vol
flask-- or any volumetric ware at all-- until their 1986-1987 catalog.6-1987 catalog.6-1987 catalog.6-1987 catalog.6-1987 catalog.6-1987 catalog.
	Also, what provides the tint-- and why red? Most catalog listing 
describe the red flasks as "low-actinic"-- does this describe the tint, or
some other property? And why not blue or green or brown?





-- 
MUDname: Sidera           "...If I seem to give a damn, please tell me. I would
University of Delaware      hate to be giving the wrong impression."
From: mmm@cup.portal.com (Mark Robert Thorson)
Newsgroups: sci.chem
Subject: Re: RE: High vacuum questions
Date: Mon, 13 Apr 92 23:32:01 PDT
Organization: The Portal System (TM)
  <11APR92.00013415@enh.nist.gov>

> 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. 
> 
> All corrections appreciated!
> 
> Karl 

You got it backwards.  The high-vacuum stage is called the backing pump,
and the stage between the backing pump and the atmosphere is called a
forepump.  This is a very common error, even among people who work with
vacuum equipment.
From: consult16@TIGGER.STCLOUD.MSUS.EDU
Newsgroups: sci.chem
Subject: alpha-bridged-pi bonds
Date: 6 Apr 92 18:31:07 GMT
Article-I.D.: msus1.1992Apr6.123108.342
Reply-To: consult16@TIGGER.STCLOUD.MSUS.EDU
Organization: St. Cloud State University, St. Cloud, MN

Can anybody point me in the direction of any more information about these.  I
am giving a P-chem seminar on this topic but have had difficulty locating
information.  The article I have now is:

alpha-bridged-pi bonding in small-ring compounds
by: Congxin Liang and Leland C. Allen
J. Am. Chem. Soc. 1991, 113, 1878-1884

If anybody has any more info, it would be greatly appreciated.

-Amy Jorgenson
Consult16@tigger.stcloud.msus.edu
From: eha@phoenix.oulu.fi (Esa Haapaniemi)
Newsgroups: sci.chem
Subject: Re: Advice wanted for school project
Date: 7 Apr 92 05:18:38 GMT
Organization: University of Oulu, Finland

kjm@sactoh0.sac.ca.us (Kevin J. Metcalfe) writes:
>      I am working on a chemistry project in school, and I would like
> a little advice.  I need to isolate stearic acid from shaving cream.  The
> four major components that I need to worry about are TEA stearate, Ceteth-20
> isobutane, and propane.  My problem is if I try to isolate it through 
> soluability characteristics, I find there is too much overlap.

As those are all soluble in water, I suppose you could use steam distillation.
Add some NaOH to make acids nonvolatile, and bubble with steam from boiling
water. All other components should leave, and the acid stays. Also it's 
readily a Na-salt for some analytical tests...
> 
> Kitty Metcalfe

Esa Haapaniemi
University of Oulu
Department of Chemistry
Finland
From: dehon@platon.Greco-Prog.FR (Dehon Olivier)
Newsgroups: sci.chem
Subject: Looking for PDB files.
Keywords: Protein Data Bank
Date: 10 Apr 92 07:14:47 GMT
Reply-To: dehon@platon.Greco-Prog.FR (Dehon Olivier)
Followup-To: sci.bio
Organization: UFR Maths Info-Bordeaux I

Could anyone send me PDB files of protein molecules or tell me where I
could find some (via ftp) ?

E-mail : dehon@platon.greco-prog.fr

Thanks in advance.
+-----------------------------------------------------------------------------+
|       	     							      |
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|Don't have a cow, man !       |      |	      Olivier Dehon (Bart)	      |
|                              | (o)(o)	      7, rue Dauzats      	      |
|I know the answer,            C      _)      33000 BORDEAUX		      |
|You know the answer,           | ,___|	      Tel : 56 96 42 59		      |
|He knows the answer !          |   /	                       		      |
|                              /____\         dehon@platon.greco-prog.fr      |
|                             /      \					      |
+-----------------------------------------------------------------------------+
From: v087n562@ubvmsb.cc.buffalo.edu (Lewis A Bernstein)
Newsgroups: sci.chem
Subject: Vacuums, et al.
Keywords: Well, I wasn't going to post this, but
Date: 13 Apr 92 20:14:00 GMT
Article-I.D.: acsu.1992Apr13.191446.27518
Organization: University at Buffalo
News-Software: VAX/VMS VNEWS 1.41


Well, I didn't think this would be necessary because I thought
everyone else who mentioned vacuum pumps would mention it, but 
glass can withstand vacuum because it is only a one atmosphere
difference from the external atmosphere.  It is a relatively 
small pressure difference.  I am not positive, but I imagine the
pressure difference to the outside air for a soda or beer bottle
can be larger than one atmosphere.  A better question would be to
ask what pressure differential can be attained with certain glass
pieces.  Of course, nicked or chipped ones will blow out easily,
with either a higher or lower pressure inside.  The results just
look more fantastic when something implodes.  

May as well ask how you are viewing your typed letters on your 
computer screen or moitor, they employ a decent vacuum that is 
intended to remain for a period of time, remember vacuum tubes?
This is the same problem.....  

Vacuum to atmospheric = 1 atm (roughly) difference in pressure.

						Lew
Newsgroups: sci.chem
Subject: High vacuum questions
From: chem@uwpg02.uwinnipeg.ca
Date: 8 APR 92 17:15:01 CST
Organization: University of Winnipeg

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
Newsgroups: sci.chem
From: rescorla@rtnmr.chem.yale.edu (Eric Rescorla)
Subject: Re: What is lighter fluid
Organization: Rescorla for himself.
Distribution: usa
Date: Mon, 6 Apr 1992 19:26:08 GMT

In article <1992Apr3.144559.20529@news.cs.brandeis.edu> st891425@pip.cc.brandeis.edu writes:
>Lighter fluid, if my memory serves me correctly, is simply butane.
>
>Right?
Depends. Standard lighter fluid, like that in a Bic lighter, is.
A Zippo (at least my Zippo) uses Naptha.
-Ekr



-- 
-------------------------------------------------------------------------------
Eric Rescorla, DoD#431, Honda CM400 rider          rescorla@rtnmr.chem.yale.edu
Yale University Department of Chemistry            We hack anything.
My mind is now for rent: C/Unix,Vacuum Tech,Machining,P-Chemist. Hire me, eh?
Newsgroups: sci.chem
Subject: Re: RE: High vacuum questions
From: srgxbhh@grace.dsir.govt.nz
Date: 15 Apr 92 07:21:29 +1200
Organization: DSIR, Gracefield, New Zealand

In article <57362@cup.portal.com>, mmm@cup.portal.com (Mark Robert Thorson) writes:
>> 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. 
>> 
>> All corrections appreciated!
>> 
>> Karl 
> 
> You got it backwards.  The high-vacuum stage is called the backing pump,
> and the stage between the backing pump and the atmosphere is called a
> forepump.  This is a very common error, even among people who work with
> vacuum equipment.

Sorry I think you both might be confused.
From High Vacuum Technique 4th Ed. by J Yarwood.
"Pumps for the production of vacua may be roughly divided into two classes;
(a) those which pump air or gas from a vessel which can be at atmospheric
    pressure initially;

(b) those which can only begin to operate below a certain pressure 
     considerably less than atmospheric, and hence require a FORE-VACUUM
    ( also known as a BACKING VACUMM)."
Note that capitals represent bold type in the book.

This indicates that the terms Fore and Backing represent the same function
for the pump, and are not seperate roles in the production of vacua.

Bruce Hamilton         SRGXBHH@grv.dsir.govt.nz 
Newsgroups: sci.chem
From: kostine@bullet.ecf.toronto.edu (KOSTINER  HELEN)
Subject: test
Organization: University of Toronto Physics/Astronomy/CITA
Distribution: ont
Date: Thu, 16 Apr 1992 20:56:47 GMT

sorry, this is just a test
From: 21796JEB@MSU
Newsgroups: sci.chem
Subject: Re: integration help
Date: 16 Apr 92 17:23:11 GMT
Organization: Michigan State University

From: v136pds9@ubvmsb.cc.buffalo.edu
asks:

>  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

Try Gradshteyn and Ryzuck, an indispensible reference book.  Your
University library certainly has a copy.
Newsgroups: sci.chem
From: robinsmm@ucsu.Colorado.EDU (ROBINSON MARYBETH)
Subject: Re: Information Request
Organization: University of Colorado, Boulder
Date: Thu, 9 Apr 1992 22:01:10 GMT

In article <1992Apr8.235707.4440@usenet.ins.cwru.edu> bg055@cleveland.Freenet.Edu (Stewart Rowe) writes:
>
>(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.

The newsgroup "sci.materials" has also had qutie a bit of infor flying
around on Buckyballs.

MB

-- 
MaryBeth (MB) Robinson    		robinsmm@ucsu.Colorado.edu
Department of Chemistry
University of Colorado
Newsgroups: sci.chem
From: bd670@cleveland.Freenet.Edu (Russell I. Dyreng)
Subject: Science Teachers' Organizations Outside the U.S.
Organization: Case Western Reserve University, Cleveland, Ohio, (USA)
Date: Tue, 7 Apr 92 21:58:11 GMT



I am trying to locate groups similar to the National Science 
Teachers' Association (NSTA) in countries outside of the United
States.  I am particularly interested in finding NSTA-type 
organizations in Canada, Western Europe and the Pacific Rim.

If you are aware of the existence of such a group, I would
appreciate you sending me the name and address of the 
organization via e-mail.

Thank you.

Russell I. Dyreng
bd670@cleveland.freenet.edu
From: kassarji@spot.Colorado.EDU (KASSARJIAN STEVEN J)
Newsgroups: sci.chem
Subject: Re: Ammonium chloride's fire resistance -- why?
Date: 17 Apr 92 19:06:25 GMT
Article-I.D.: ucsu.1992Apr17.190625.311
Organization: University of Colorado, Boulder

In article <1992Apr14.150613.8195@pbhya.PacBell.COM> gdridle@pbhya.PacBell.COM (Guy D. Ridley) writes:
>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.)
...
>Guy Ridley
>pacbell!pbhya!gdridle

One fire retardant used for polystyrene is monochloro-pentabromo cyclohexane.
When the compound is subjected to fire, the result is a (nasty) dense fog of 
chlorine and bromine radicals/ions (I don't know which, nor does it matter).
The density of the halogen fog excludes oxygen, and helps extinguish the fire.

Regards,
Steve Kassarjian
kassarji@spot.Colorado.edu
From: bosse@snus.met.kth.se (Bo Sundman)
Newsgroups: sci.chem
Subject: Re: Iron Oxide
Summary: phases in Fe-O
Keywords: wustite, spinel, corundum
Date: 7 Apr 92 23:18:53 GMT
Organization: Phys. Metallurgy, KTH, Sweden

The discussion on ironoxides seems to need some facts.  Iron has three
stable oxides with different structures. One reason for this is that
iron may have valency +2 and +3.

Wuestite has an NaCl structure with O on one set of sites and Fe on
the other. There is no stoichiometric FeO but wuestite has a variable
iron content between Fe0.947O to about Fe0.85O. In this structure Fe
has both valencies and vacant sites in the NaCl structure in order to
maintain electroneutrality. Additionally wuestite decomposes around
830 C to bcc+Fe3O4.

Magnetite, Fe3O4, has a different structure called spinel found among
many minerals, the name is derived from the MgAl2O3 spinel. In the
spinel the O ions are again on an fcc lattice wheras the Fe+2 and Fe+3
occupy octahedral and tetrahedral interstitial sites. In order to make
it more complicated Fe3O4 is a so called inverse spinel. Magnetite has
also a variable composition but much less than wuestite.

Finally Fe2O3 has a corundum structure, same as Al2O3. There is also
a metastable Fe2O3 phase with a cubic structure.
Newsgroups: sci.chem
From: gay@selkirk.sfu.ca (Ian D. Gay)
Subject: Re: Iron Oxide
Organization: Simon Fraser University, Burnaby, B.C., Canada
Date: Tue, 7 Apr 1992 16:30:28 GMT

yan@mercury.cs.uregina.ca (Yongfei Yan) writes:


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


>         John Yan

It is _NOT_ a mixture. It is a distinct crystalline phase that 
contains both Fe(II) and Fe(III).