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From: metzger@cup.portal.com (David G Metzger)
Newsgroups: sci.electronics
Subject: Re: Do Halogen lamps need ballasts?
Message-ID: <36440@cup.portal.com>
Date: 2 Dec 90 01:46:10 GMT
References: <714@skipper.dfrf.nasa.gov> <1147@inews.intel.com>
  <1990Dec1.032426@envy.bellcore.com> <1197@inews.intel.com>
Organization: The Portal System (TM)
Lines: 28

In article <1197@inews.intel.com>, bhoughto@cmdnfs.intel.com
   (Blair P. Houghton) writes:

>In article <1990Dec1.032426@envy.bellcore.com> karn@thumper.bellcore.com write
s
>:
>>In article <1147@inews.intel.com>, bhoughto@cmdnfs.intel.com (Blair P.
>>Houghton) writes:
>[...deformation ==> rupture...]
>>|> The oil doesn't "weaken the structure."  You can
>>|> wipe it off.
>>
>>I don't think that's quite right. Quartz is used precisely
>>because of its very low temperature expansion coefficient.
>
>Very low != nonexistant.  Also, quartz is very brittle.
>Any deformation causes catastrophic displacement
>(cleaving).  When there's a uniformity of heat
  ^^^^^^^^
>distribution, things expand normally.  When there isn't,
>they don't.

     Quartz does not have cleavage planes.  When quartz breaks, it
is by conchoidal fracture.

                                   David Metzger
                                   metzger@cup.portal.com
                                   sun!portal!cup.portal.com!metzger


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