Subject: Is there a market for activated carbon sheet electrodes.
From: Marc Andelman
Date: Thu, 14 Nov 1996 11:38:46 -0800
Hi. I am curious if people in this newsgroup have need for
high surface area carbon electrodes. I have found this stuff
to be ridiculously expensive, and have a need myself. Furthermore,
I have found a way to make this material far cheaper than
currently on the market, and at a much higher quality.
My question is, am I the only one who needs this stuff in
quantity, or are there additional markets/
Regards,
Marc Andelman
Subject: Re: Dielectric properties of water
From: peterson.rob@worldnet.net (Rob Peterson)
Date: Fri, 15 Nov 1996 03:44:39 GMT
you@somehost.somedomain (Mr Chickens) wrote:
>In article <5654ak$dfj@mtinsc01-mgt.ops.worldnet.att.net>,
>peterson.rob@worldnet.net says...
>>I haven't looked anything up yet but clearly the dielectric changes
>>from 80 (at least into the GHz range) to something like 2 at optical
>>frequencies where the index of refraction is around 1.5 (since n goes
>>as squrare root of dielectric). eg, the velocity at microwave
>>frequencies goes as c/root(81) or about 1/9 of speed of light.
>>Not much help but this does tell you that dielectric drops a lot
>>towards optical frequencies. The only other thing I can think of is
>>that the loss tangent which is serious for salt water at microwave
>>obviously drops to zip at optical (the old sigma/omega term).
>>Good luck and please let me know if you get any simple answers to
>>this.
>>Rob
>>
>Hi,
>Thanks for the initial info, I've been having a look
>in a couple of reference books and can probably
>work out the dielectric variation by using an extension
>of the equation for plasma frequencies in solids. This
>directly relates the electronic polarization of molecules
>to the relative permittivity of a material and hopefully
>this includes fluids as well!
>Does this make any sense to you?
>Unfortunately my background does not extend too heavily into
>solid state physics so theres a bit of work to be done yet.
>-Sigh..
I'm no solid or liquid state guy myself but I have run into lots of
detail on this subject in the literature. I think you will find this
worked out in some detail where the envelope of the curve is first
described and then the various atomic/molecular rotational,
vibrational, and electronic resonances generate fine structure.
Clearly, it's not something I'm very familar with but I've been forced
to deal with bits and pieces of this from time to time and I should
understand it much better than I do (the basis of my interest here).
I'll try to prowl the subject when I get time and may email you
anything that may be useful to you. Can you give me more info on your
particular interest in this?
Rob
Subject: Re: High Temperature pH sensitive glass
From: mj_danielson@pnl.gov (Mike Danielson)
Date: 12 Nov 1996 18:32:54 GMT
In article <328661A3.3C79@pjc-ent.com>, sheila@pjc-ent.com
says...
>
>Does anyone know of a source for the formulation of high
temperature
>(100 degrees C +) pH sensitive glass.
>
>Thanks,
>
>Sheila Cox at sheila@pjc-ent.com
Sheila, I believe the pH electrode manufacturers formulate their
own glass and blow the pH-sensitive bulbs at their manufacturing
facility. Corning used to sell the 015 glass formulation to
outsiders. Get in contact with Micro-Electrodes or Corning or
Fisher Scientific to see if they will sell you their newer glass
formulations. There are researchers who need to construct their
own glass pH sensors because, for instance, the tip must be
drawn down to cellular dimensions for insertion into a single
cell, and no manufactuerer could ship them and they arrive in
one piece. I hold out lots of hope for your quest.
Mike Danielson