In message <4cf29e0a.2020...@xtra.co.nz>, Bruce Griffiths writes:
>jimlux wrote:
>Removing the water from it (result of the "fabrication" technique)
>without destroying its mechanical integrity is.
>One method is to use supercritical liquid carbon dioxide.
I don't think there is any other method
jimlux wrote:
Poul-Henning Kamp wrote:
In message <4cf1d64e.2010...@earthlink.net>, jimlux writes:
Poul-Henning Kamp wrote:
We use aerogel for insulation in Mars rovers.. Those little RHUs
don't put out a lot of heat, and you don't have much electronics on
at night.
Do you know if that i
In message <4cf26fe2.40...@earthlink.net>, jimlux writes:
>Poul-Henning Kamp wrote:
>There's a fair number of "recipes" around to make your own aerogel.
The CO2 route is pretty safe, but be very carefull with the alcohol
route, the swedes blew up a lab with supercritical alcohol once...
--
Poul
Poul-Henning Kamp wrote:
In message <4cf1d64e.2010...@earthlink.net>, jimlux writes:
Poul-Henning Kamp wrote:
We use aerogel for insulation in Mars rovers.. Those little RHUs don't
put out a lot of heat, and you don't have much electronics on at night.
Do you know if that is in big blocks
In message <4cf1d64e.2010...@earthlink.net>, jimlux writes:
>Poul-Henning Kamp wrote:
>We use aerogel for insulation in Mars rovers.. Those little RHUs don't
>put out a lot of heat, and you don't have much electronics on at night.
Do you know if that is in big blocks or in granular form ?
--
There is a very similar material used to line restaurant vent hoods.
It is some sort of ceramic foam insulation board.
-Chuck Harris
In any case, the stuff is avaiablee in commercial forms from the usual
sources I'd start with Thermal Ceramics
___
t
J. Forster wrote:
At this point, bits of the Shuttle are "collectibles" and are priced
accordingly. Just like genuine Apollo bits, they aren't making it any
more. What was a couple of bucks surplus in the 1960s now brings far more.
FWIW,
-John
=
No more costly than big pieces
Poul-Henning Kamp wrote:
In message <05fb5f7f819d035fdc8556f9b4842b98.squir...@webmail.sonic.net>, "Rick
Karlquist" writes:
The general consensus was that
all foams were more or less similar thermally,
There is indeed very little difference, in particular if the foam
is encapsulated so the
I have a "connection." I'll inquire, just for the heck of it, and let you
know.
On Sat, Nov 27, 2010 at 7:00 PM, J. Forster wrote:
> At this point, bits of the Shuttle are "collectibles" and are priced
> accordingly. Just like genuine Apollo bits, they aren't making it any
> more. What was a
At this point, bits of the Shuttle are "collectibles" and are priced
accordingly. Just like genuine Apollo bits, they aren't making it any
more. What was a couple of bucks surplus in the 1960s now brings far more.
FWIW,
-John
=
> No more costly than big pieces of aerogel and, si
No more costly than big pieces of aerogel and, since NASA's acceptance
standards are so high there has to be some around that failed quality
checks
On Sat, Nov 27, 2010 at 6:30 PM, J. Forster wrote:
> You could probably buy enough pink fiberglass to insulate a house for what
> one of thos
You could probably buy enough pink fiberglass to insulate a house for what
one of those cost. They might even cost more on eBay
-John
===
> How about surplus HRSI tiles off the Shuttle?
>
>
>
> On Sat, Nov 27, 2010 at 1:47 PM, Poul-Henning Kamp
> wrote:
>
>> In message
>> <05fb5f7f8
How about surplus HRSI tiles off the Shuttle?
On Sat, Nov 27, 2010 at 1:47 PM, Poul-Henning Kamp wrote:
> In message <05fb5f7f819d035fdc8556f9b4842b98.squir...@webmail.sonic.net>,
> "Rick
> Karlquist" writes:
>
> >The general consensus was that
> >all foams were more or less similar thermally,
In message <52830.12.6.201.2.1290877633.squir...@popaccts.quikus.com>, "J. Fors
ter" writes:
>The two (before and after ?) pics look like they have different contrast
>settings.
They are actually not before and after, they are the same image in
four different representations.
The first (set of f
In message <05fb5f7f819d035fdc8556f9b4842b98.squir...@webmail.sonic.net>, "Rick
Karlquist" writes:
>The general consensus was that
>all foams were more or less similar thermally,
There is indeed very little difference, in particular if the foam
is encapsulated so the open/closed bubble differen
FWIW:
During the development of the E1938A, we tried replacing
the foam insulation with a skeleton plastic frame with knife
edges. The idea was that the plastic would have negligible
heat conduction, leaving only air convection and radiation.
We didn't see much difference between this set up and
The two (before and after ?) pics look like they have different contrast
settings.
-John
===
> In message <013e01cb8dc6$41b038a0$4001a...@lark>, "Alan Melia" writes:
>
>>I believe there is a reflective/foam insulator that is sold for setting
>>behind (what we in UK call ) CH radiators wh
In message <013e01cb8dc6$41b038a0$4001a...@lark>, "Alan Melia" writes:
>I believe there is a reflective/foam insulator that is sold for setting
>behind (what we in UK call ) CH radiators when the are mounted on outer
>walls. That would meed Poul-Henning's temperature difference criteria, I
>think.
Hi
It's a fused fiber material, more like the stuff they make overnight shipping
envelopes out of than a normal paper. It looks and feels more like tissue paper
than anything else though. The same outgassing and particles floating around
issues mess up the gaps in the sandwich. There are indeed
I'm virtually certain by 1968 they were using some plastic film. Maybe
Mylar, maybe Kapton, but metalized plastic. I was doing optics and
telemetry so was not really involved in other areas, but I babysat our
payload on that bird first bird for 5 months
-John
> Bob Camp wrote:
>> H
Bob Camp wrote:
Hi
The ones I'm talking about aren't used anywhere there's air to create any
wind
Bob
yeah, but there's plenty of handling and air currents before it gets
launched...
These days, I'd vote for evaporated metal on some substrate.
Bob Camp wrote:
Hi
The gold color in a space thermal blanket is from - gold. The normal formula is to use gold leaf and tissue paper (not quite the Kleenex variety, but similar) in layers. The gold leaf is *very* good for IR reflection. The tissue paper is porous enough that there's very little
> Dont get the idea that radiation is only significant for large
> temperature differences.
> For two parallel surfaces at any distance apart the black body
> radiation between them (around room temperature 300K) is near to 6
> watts per square metre per degree (C*) of temperature difference.
Only
Dont get the idea that radiation is only significant for large
temperature differences.
For two parallel surfaces at any distance apart the black body
radiation between them (around room temperature 300K) is near to 6
watts per square metre per degree (C*) of temperature difference.
That is
Hi
The ones I'm talking about aren't used anywhere there's air to create any
wind
Bob
On Nov 26, 2010, at 6:52 PM, J. Forster wrote:
> Not leaf in the ones I've seen. It's very clearly a metalized plastic
> film. Gold leaf has virtually no structural strength. A breeze will tear
> it. I a
ysics
:-))
Alan G3NYK
- Original Message -
From: "jimlux"
To: "Discussion of precise time and frequency measurement"
Sent: Friday, November 26, 2010 11:41 PM
Subject: Re: [time-nuts] temperature stability basics
> Hal Murray wrote:
> > namic...@gmail.co
Not leaf in the ones I've seen. It's very clearly a metalized plastic
film. Gold leaf has virtually no structural strength. A breeze will tear
it. I also doubt any tissue paper usage.
Best,
-John
=
> Hi
>
> The gold color in a space thermal blanket is from - gold. The normal
>
Aren't the "space blankets" use in survival packs pretty much the same
stuff? The mylar-air space-mylar construction seems pretty rational, and
they are windproof.
-John
===
> Hal Murray wrote:
>> namic...@gmail.com said:
>>> Find some closed cell polyethylene that is quite thin and
Hi
The gold color in a space thermal blanket is from - gold. The normal formula is
to use gold leaf and tissue paper (not quite the Kleenex variety, but similar)
in layers. The gold leaf is *very* good for IR reflection. The tissue paper is
porous enough that there's very little air trapped in
J. Forster wrote:
That's what those golden thermal blankets are on spacecraft and in
cryostats. I'm not quite sure whether the golden color comes from a
deposited film of Au, or whether it's color comes from the Mylar. It's
more likely the former. I've seen the stuff up close, but have not worked
Hal Murray wrote:
namic...@gmail.com said:
Find some closed cell polyethylene that is quite thin and some very light
aluminium foil and you could make many layers.
How about aluminized Mylar?
If the many-reflective-layers idea really works, I'd expect somebody to sell
foam built that way. W
In message <20101126223543.71514800...@ip-64-139-1-69.sjc.megapath.net>, Hal Mu
rray writes:
>How about aluminized Mylar?
Reflective insulation only works if you have significantly different
temperatures.
Look up Stefan-Bolzmanns law, and notice the T^4 term, but pay attention
to T being absolut
That's what those golden thermal blankets are on spacecraft and in
cryostats. I'm not quite sure whether the golden color comes from a
deposited film of Au, or whether it's color comes from the Mylar. It's
more likely the former. I've seen the stuff up close, but have not worked
wit it personally.
namic...@gmail.com said:
> Find some closed cell polyethylene that is quite thin and some very light
> aluminium foil and you could make many layers.
How about aluminized Mylar?
If the many-reflective-layers idea really works, I'd expect somebody to sell
foam built that way. Why don't they?
-
On 11/26/2010 07:17 PM, Mark Sims wrote:
One thing to be aware of with the LM35 type of sensors in the TO92 package is
that virtually all of the temperature input to the chip is via the leads (fine
print in the data sheet). I have seen several places with the device package
epoxied to some s
One thing to be aware of with the LM35 type of sensors in the TO92 package is
that virtually all of the temperature input to the chip is via the leads (fine
print in the data sheet). I have seen several places with the device package
epoxied to some surface or embedded in some insulation with
Hi
The other answer is to let the temperature control electronics take care of the
problem. If you are doing something inside that uses energy (like an
oscillator) it have generate a heat rise through the insulation.
Bob
Sent from my iPhone
On Nov 26, 2010, at 2:24 AM, "beale" wrote:
> In a
In message <4cefd115.5030...@earthlink.net>, jimlux writes:
>beale wrote:
>What is done in real instruments that need good thermal insulation?
>I assume dewar flasks are limited to aerospace applications.
One good allround foam material is "Armaflex"
--
Poul-Henning Kamp | UNIX since Zilo
Worse. Those books will start you thinking about home brew H MASERS. T^hey
make UHV seem doable.
-John
===
> John Strong's "Procedures in Experimental Physics" has a section on
> thermal design (for furnaces and ovens), and is worth having a copy of.'
> Moore, et.al., "building scie
Thermos flasks were pretty common on early crystal oscillatots, including
GR, HP 107(?), and Sultzer at least.
-John
> In an attempt to educate myself about temperature stability, I put a
> temperature sensor in a 1" cube of brass wrapped in plastic packing-type
> bubble wrap,
beale wrote:
In an attempt to educate myself about temperature stability, I put a temperature
sensor in a 1" cube of brass wrapped in plastic packing-type bubble wrap, and
compared that with another sensor outside the bubble wrap, with the whole
combination in a thin nylon case just to slow do
Hi,
I have been looking at a similar problem. What I have found is:
many plastic foam materials have very low conduction but are
transparent to long wavelength radiation, so thermal heating/cooling
through them is mainly by thermal radiation.
If you wrap an item in plastic foam, then a radiati
Hi Beale,
From: "beale"
I assume dewar flasks are limited to aerospace applications.
:-) You keep your coffee hot in it!
Bye,
Jean-Louis Noel, OO1J
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To unsubscribe, go to https://www.febo.com/cgi-
In an attempt to educate myself about temperature stability, I put a
temperature sensor in a 1" cube of brass wrapped in plastic packing-type bubble
wrap, and compared that with another sensor outside the bubble wrap, with the
whole combination in a thin nylon case just to slow down direct air d
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