In article ,
Norman Wells wrote:
Now you're introducing red herrings. We're not talking about diving or any
increase in ambient presuure, which would of course increase the solubility
of any gas in a fluid, but a situation at constant pressure. Whatever the
concentration of nitrogen in the 'air' that is breathed in, the pressure
remains constant, so the amount of nitrogen that can be dissolved in the
water of the blood remains constant.

At constant atmospheric pressure, as the concentration of nitrogen
in the gas that is breathed in increases, the partial pressure of
nitrogen in the blood (and other body tissues) will also increase.
Does that not increase the *amount* of nitrogen too, contrary to
what you wrote above?

Francis

"Chris Lewis" wrote in message
...

Hydrogen is not even used to fill balloons at children's parties these
days, whereas it was commonly used when I was a child AFAIR. Helium,
like oil, is a non-renewable commodity - after we have mined the last
litre of helium there is no way to make more in any quantity.
Hydrogen OTOH is readily manufactuable in whatever quantities we need.

--
Cynic


Do you have any info on these 'helium mines' you speak of? I would love
to see how one of those works.


There are no 'helium mines' as such. Helium is in fact found in natural gas
deposits and the concentration varies considerably. The largest
concentrations are found in the US and Russia of up to several percent
making it viable to extract it by fractional distillation of the gas. Well,
not quite, what they do is liquify every other gas out and what's left is
nearly pure helium.

The helium extracted eventually finds its way into the atmosphere but any
excess escapes into space leaving the atmospheric concentration more or less
constant at a very low level (a few parts per million).

"Francis Burton" wrote in message
...
In article ,
Alter Ego wrote:
Anyone with any understanding of the subject would know that Zyklon-B
was
not a gas, but a solid. When used, it gave off hydrogen cyanide which
is
the gas used in the gas chambers.

Anyone with any understanding of the subject would know that Zyklon-B was
not a solid but a liquid. It doesn't give off hydrogen cyanide because it
_is_ hydrogen cyanide.

And the "stabilizer, and a warning odorant that were impregnated onto
various substrates, typically small absorbent pellets, fibre discs, or
diatomaceous earth" - those were not part of Zyklon-B?


I believe the stabilizer was also a liquid. The only solid part was the
pellets that carried the Zyklon-B, but they were not actually part of the
formulation, just the carrier.

Whatever the warning odorant was (probably a liquid as it had to evaporate),
it was deliberately omitted from the Zyklon-B manufactured for gas chamber
use in violation of international law. I believe that the directors of at
least some of the companies who produced the odor free Zyklon-B were treated
as war criminals.

On Thu, 27 Nov 2008 08:47:07 -0000, "Chris Lewis"
wrote:

Hydrogen is not even used to fill balloons at children's parties these
days, whereas it was commonly used when I was a child AFAIR. Helium,
like oil, is a non-renewable commodity - after we have mined the last
litre of helium there is no way to make more in any quantity.
Hydrogen OTOH is readily manufactuable in whatever quantities we need.

Do you have any info on these 'helium mines' you speak of? I would love to
see how one of those works.

Yes, I was also surprised and amused when I first read, years ago,
that helium is mined. An Internet search shows that the terminology
today is to refer to helium wells rather than helium mines, which is
more accurate as IIUC the gas is extracted by drilling rather than
tunnelling to the underground pockets in which it is trapped.

--
Cynic

On Thu, 27 Nov 2008 10:51:11 -0000, "M.I.5¾"
wrote:

Hydrogen is not even used to fill balloons at children's parties these
days, whereas it was commonly used when I was a child AFAIR. Helium,
like oil, is a non-renewable commodity

Although that would seem to be a reasonable assumption, it is not in fact
the case. The supply of helium is in fact constantly renewing itself. The
only problem is that the rate of consumption at present far exceeds the rate
of renewal.

Yes, so my statement is essentially correct. Exactly the same
comments could be made about oil, which is also constantly renewing
itself, but at a slower rate than our consumption of it.

--
Cynic

"M.I.5¾" wrote in message
...

"Cynic" wrote in message
...
On Wed, 26 Nov 2008 15:03:09 -0000, "M.I.5¾"
wrote:

That's true - however it *is* known what dope was used, and
experiments using the same material have shown how dangerous it was,
and how easily ignitable.


I'm racking my brains here but ISTR from a TV documentary that the dope
itself actually contained a powerful oxidiser as well as being flammable
in
its own right. An ideal combination for a hydrogen airship.

I don't recall too many of the details, but the main point is that
hydrogen is usually exclusively blamed for the disaster when more
balanced reasoning would point a finger more at the design and choice
of materials.

As a consequence, hydrogen is now considered far too dangerous to use
as a lifting gas, where the reality is that it could be used with an
acceptable risk factor if the vehicle were to be designed with safety
in mind. After all, millions of cars are on the road, each containing
a tank of extremely inflammable liquid, and only a very tiny
percentage end up in flames.

Hydrogen is not even used to fill balloons at children's parties these
days, whereas it was commonly used when I was a child AFAIR. Helium,
like oil, is a non-renewable commodity

Although that would seem to be a reasonable assumption, it is not in fact
the case. The supply of helium is in fact constantly renewing itself.
The only problem is that the rate of consumption at present far exceeds
the rate of renewal. Helium is the product of radioactive decay.
Radioactive material that emits alpha particles creates helium when those
particles capture a couple of electrons each which the do very easily.

It's probably also worth noting that once the problems with thermo nuclear
power generation are solved that that process will provide a supply of
helium as that is the reaction product. Although it will be helium-3 rather
than helium-4, it will have a little more lifting power.

In article ,
Alter Ego wrote:
Anyone with any understanding of the subject would know that Zyklon-B was
not a solid but a liquid. It doesn't give off hydrogen cyanide because it
_is_ hydrogen cyanide.

And the "stabilizer, and a warning odorant that were impregnated onto
various substrates, typically small absorbent pellets, fibre discs, or
diatomaceous earth" - those were not part of Zyklon-B?

I believe the stabilizer was also a liquid. The only solid part was the
pellets that carried the Zyklon-B, but they were not actually part of the
formulation, just the carrier.

So a bit like paracetamol in tablet form - one can refer to them
as "paracetamol tablets" even though the paracetamol itself is a
fraction of the tablet. It would not be incorrect to refer to the
solid contents of the Zyklon-B canisters as "Zyklon-B" even though
the Zyklon-B itself was a liquid.

Whatever the warning odorant was (probably a liquid as it had to evaporate),
it was deliberately omitted from the Zyklon-B manufactured for gas chamber
use in violation of international law. I believe that the directors of at
least some of the companies who produced the odor free Zyklon-B were treated
as war criminals.

The presence of a warning odorant strikes me as slightly odd because
cyanide itself has a very strong and distinctive smell (at least to
my nose) at low concentrations. At least some of the people exposed
to it would immediately recognize the smell, I would have thought.

Francis

In article ,
Mr X wrote:
"Norman Wells" wrote in message
...
[...]
Now you're introducing red herrings. We're not talking about diving or
any increase in ambient presuure, which would of course increase the
solubility of any gas in a fluid, but a situation at constant pressure.
Whatever the concentration of nitrogen in the 'air' that is breathed in,
the pressure remains constant, so the amount of nitrogen that can be
dissolved in the water of the blood remains constant.

It isn't a read herring I'm trying to use an example to explain it. It
sounds to me that you don't understand the concept of a partial pressure of
a gas.

I'm not sure either that Norman Wells understood the concept of
partial pressure when he wrote the above (and before he disappeared).

Francis

"Francis Burton" wrote in message
...
In article ,
Mr X wrote:
"Norman Wells" wrote in message
...
[...]
Now you're introducing red herrings. We're not talking about diving or
any increase in ambient presuure, which would of course increase the
solubility of any gas in a fluid, but a situation at constant pressure.
Whatever the concentration of nitrogen in the 'air' that is breathed in,
the pressure remains constant, so the amount of nitrogen that can be
dissolved in the water of the blood remains constant.

It isn't a read herring I'm trying to use an example to explain it. It
sounds to me that you don't understand the concept of a partial pressure
of
a gas.

I'm not sure either that Norman Wells understood the concept of
partial pressure when he wrote the above (and before he disappeared).

Based on his past posts I'm not sure he understands anything. He seems to
say black is white if it suits him.

"Francis Burton" wrote in message
...
In article ,
Alter Ego wrote:
Anyone with any understanding of the subject would know that Zyklon-B
was
not a solid but a liquid. It doesn't give off hydrogen cyanide because
it
_is_ hydrogen cyanide.

And the "stabilizer, and a warning odorant that were impregnated onto
various substrates, typically small absorbent pellets, fibre discs, or
diatomaceous earth" - those were not part of Zyklon-B?

I believe the stabilizer was also a liquid. The only solid part was the
pellets that carried the Zyklon-B, but they were not actually part of the
formulation, just the carrier.

So a bit like paracetamol in tablet form - one can refer to them
as "paracetamol tablets" even though the paracetamol itself is a
fraction of the tablet. It would not be incorrect to refer to the
solid contents of the Zyklon-B canisters as "Zyklon-B" even though
the Zyklon-B itself was a liquid.


Actually very little of a paracetamol is not actually paracetamol. The
carrier for Zyklon-B varied from manufacturer to manufacturer so could not
really be considered part of the formulation.

Whatever the warning odorant was (probably a liquid as it had to
evaporate),
it was deliberately omitted from the Zyklon-B manufactured for gas chamber
use in violation of international law. I believe that the directors of at
least some of the companies who produced the odor free Zyklon-B were
treated
as war criminals.

The presence of a warning odorant strikes me as slightly odd because
cyanide itself has a very strong and distinctive smell (at least to
my nose) at low concentrations. At least some of the people exposed
to it would immediately recognize the smell, I would have thought.


AIUI, Zyklon B was developed as a pesticide for applications such as
delousing. In the low level concentrations required for such use the odor
of the HCN would most likely go un-noticed, hence the requirement for a
warning odorant. This is apparently a requirement in such product under
international law anyway.

As we all know, it was the nazis who found an alternate use and deleted the
odorant. Whether any of the victims were able to detect the HCN without it,
I'll guess we'll never know.