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Partial pressure of O2, CO2, etc., in Thailand cave

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  Partial pressure of O2, CO2, etc., in Thailand cave cornelius@eisner.decus.org (George Cornelius) - 2018-07-07 20:55 -0400
    Re: Partial pressure of O2, CO2, etc., in Thailand cave cornelius@eisner.decus.org (George Cornelius) - 2018-07-07 21:30 -0400
    Re: Partial pressure of O2, CO2, etc., in Thailand cave cornelius@eisner.decus.org (George Cornelius) - 2018-07-07 22:19 -0400
    Re:Partial pressure of O2, CO2, etc., in Thailand cave Libor Striz <poutnik4REMOVEnntp@CAPITALSgmail.com> - 2018-07-08 06:11 +0200
      Re: Re:Partial pressure of O2, CO2, etc., in Thailand cave cornelius@eisner.decus.org (George Cornelius) - 2018-07-08 01:14 -0400
        Re: Re:Partial pressure of O2, CO2, etc., in Thailand cave Libor Striz <poutnik4REMOVEnntp@CAPITALSgmail.com> - 2018-07-08 07:30 +0200
          Re: Re:Partial pressure of O2, CO2, etc., in Thailand cave cornelius@eisner.decus.org (George Cornelius) - 2018-07-09 02:40 -0400

#693041 — Partial pressure of O2, CO2, etc., in Thailand cave

Regarding flooded caves and partial pressures of key gases.

Lots of people want to talk about the current situation at
Doi Nang Non mountain but some have special knowledge that
might be tapped.

Currently there are dicussions about the low oxygen partial
pressure (percentage, presumably by volume) of 15% at the
team's location compared to a normal value of 21%, this new
level already at the point where it can be causing some
impairment.

Sites like this one have graphic froms which one might hope
to inferred at least some sort of scale information (beware
possible wrap of URL):

 www.cbsnews.com/news/thailand-cave-rescue-latest-updates-today-officials-appear-close-to-launching-rescue-mission-2018-07-07/

Now if water volume is lowered and air volume is increased by
the same amount, something must occur to make up the difference.
According to South Dakota School of Mines these are limestone
formations and therefore quite porous, and, in fact, diffusion
through the limestone may be a major source of replenishment
of the removed water during the monsoon season.

So what is happening in the air spaces to deal with the
increased air volume?

Possibilities:

 o Concomitant lowering of pressure while relative pressures
   remain the same?

 o Ditto, except P_H20 remains constant (partial pressure
   H2O at maximum value for given temperature).

 o Combination effects, with, say chemical reactions or outgassing,
   changing the contributions of other gasses as well.

I am here ignoring the partial pressure of CO2. Of course it
will  be going up as O2 is consumed by the humans in the cavity,
but since some of the waste product of energy production in the
body is H2O, there should be a smaller volume of CO2 produced
than O2 consumed, say, roughly, 2:1.

Finally, between two sealed cavities, does not a water-filled
connecting tunnel act like a manometer so that water level will
rise in the lower pressure chamber relative to the higher
pressure chamber?  Does that mean that if the chamber containing
the team is smaller its water level may remain higher and air
volume lower as the water in the other chambers is drained?
Maybe this is moot because of the permeability of the
limestone in which they are presumably embedded.

George

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#693042

In article <a3TEG7FpUeMY@eisner.encompasserve.org>, cornelius@eisner.decus.org (George Cornelius) writes:
> Regarding flooded caves and partial pressures of key gases.
> 
> Lots of people want to talk about the current situation at
> Doi Nang Non mountain but some have special knowledge that
> might be tapped.

In view of the fact that this really is a life or death situation,
could we at least in the early stages of this defer to those
who have a really authoritative knowledge on one of these
subjects?   I have stated my thoughts as a starting point but
do not have special knowledge beyond first year college chemistry
and physics and whatever I know of thermodynamics and classical
mechanics, and I know nothing to speak of about caves or geology.

Also, sorry for the typos... that last second edit always gets
me into trouble.

George

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#693052

In article [...], cornelius@eisner.decus.org writes:

> Sites like this one have graphic froms which one might hope[...]

Demangled:

"Sites like this one have graphics from which one might hope
to infer at least some sort of scale information:

 www.cbsnews.com/news/thailand-cave-rescue-latest-updates-today-officials-appear
-close-to-launching-rescue-mission-2018-07-07/"


George

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#693057

cornelius@eisner.decus.org (George Cornelius) Wrote in message:
>.
> 

> I am here ignoring the partial pressure of CO2. Of course it
> will  be going up as O2 is consumed by the humans in the cavity,
> but since some of the waste product of energy production in the
> body is H2O, there should be a smaller volume of CO2 produced
> than O2 consumed, say, roughly, 2:1.
> 
The major metabolic source of energy - oxidation of glucose - has
 the total chemical reaction as
C6H12O6(glucose) + 6 O2 --> 
6 H2O + 6 CO2., Therefore 1:1

For fat, it can be  simplified by ommiting the minor glycerol
 ester part as just
2 (CH2)n + 3n O2 --> 2n CO2 + 2n H2O, 
so 3:2.

Large portion of CO2 will be dissolving in water, some small part
 of it dissolving the limestone
CO2 + H2O + CaCO3 --> Ca(HCO3)2

The relative  humidity will be close to 100%, absolute  humidity
 in g/me will be near constant as well as temperature. Excessive
 water vapour  will eventually condense.

The eventual pressure decrease due decrease of total amount of
 gasses will be mostly eliminated by sucking air via limestone 
 porosity  and sucking water to decrease volume and increase
 pressure. These effects lead to both absolute and partial
 pressure increase of air gasses but CO2, which partial pressure
 increase will be much smaller.

1 % of CO2 reportedly start causing breathing problem, as
 increased CO level on blood trigger response of hypothalamus  to
 intensify breathing to get rid of it .
10 % has already an anaesthetic effect. ( Quotes Q&A source )

The questing remains, what was the initial  oxygen concentration
 before flooding. Even if the internal  space was directly
 connected to open air, the cave system  is long enough to differ
 from average air concentration. E.g oxygen can be spent by
 oxidation of iron and manganese minerals and by cave life
 forms.

-- 
Libor Striz aka Poutnik ( a pilgrim/wanderer/wayfarer)

"Humour is the only effective weapon against stupidity."
Miloš Forman


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

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#693064

In article <phs2tm$n6k$1@dont-email.me>, Libor Striz <poutnik4REMOVEnntp@CAPITALSgmail.com> writes:
> cornelius@eisner.decus.org (George Cornelius) Wrote in message:
 
>> I am here ignoring the partial pressure of CO2. Of course it
>> will  be going up as O2 is consumed by the humans in the cavity,
>> but since some of the waste product of energy production in the
>> body is H2O, there should be a smaller volume of CO2 produced
>> than O2 consumed, say, roughly, 2:1.
 
> The major metabolic source of energy - oxidation of glucose - has
>  the total chemical reaction as
> C6H12O6(glucose) + 6 O2 --> 
> 6 H2O + 6 CO2., Therefore 1:1

Thank you.  I had completely forgotten that sugars have
a large number of oxygen atoms.  Don't recall ever
memorizing the chemical formula for glucose although I
at one time could tell you one of the others - I suppose
sucrose.
 
> For fat, it can be  simplified by ommiting the minor glycerol
>  ester part as just
> 2 (CH2)n + 3n O2 --> 2n CO2 + 2n H2O, 
> so 3:2.
> 
> Large portion of CO2 will be dissolving in water, some small part
>  of it dissolving the limestone
> CO2 + H2O + CaCO3 --> Ca(HCO3)2

Yes, I had long since forgotten the reaction that transforms
aqueous CO2 and CaCO3 into limestone, but I knew it existed.
And I did expect at least some of the CO2 to dissolve in water.

In any case, the outcome is similar to what I proposed, that O2
relative percentages decrease while CO2 changes are not as significant,
and this is good because the feeling of suffocation you get in
confined spaces is apparently due to excess CO2 and not the
lack of oxygen.
 
> The relative  humidity will be close to 100%, absolute  humidity
>  in g/me will be near constant as well as temperature. Excessive
>  water vapour  will eventually condense.

My assumption as well.

> The eventual pressure decrease due decrease of total amount of
>  gasses will be mostly eliminated by sucking air via limestone 
>  porosity  and sucking water to decrease volume and increase
>  pressure. These effects lead to both absolute and partial
>  pressure increase of air gasses but CO2, which partial pressure
>  increase will be much smaller.

OK, so porosity effects do apply.  As the monsoon season
progesses is it possible the limestone becomes closer to
being saturated with water and less capable of bearing
oxygen and other gases?
 
> 1 % of CO2 reportedly start causing breathing problem, as
>  increased CO level on blood trigger response of hypothalamus  to
>  intensify breathing to get rid of it .
> 10 % has already an anaesthetic effect. ( Quotes Q&A source )
> 
> The questing remains, what was the initial  oxygen concentration
>  before flooding. Even if the internal  space was directly
>  connected to open air, the cave system  is long enough to differ
>  from average air concentration. E.g oxygen can be spent by
>  oxidation of iron and manganese minerals and by cave life
>  forms.

Difficult to know unless someone has studied it in the past
or someone is routinely recording such things over time.  And
I doubt if the divers, upon arriving initially, might have
both collected an air sample and measured absolute air
pressure.

I have heard that there were later readings after the reported
15% O2 number and that it has climbed back up to 17%.  Perhaps
there has been some oxygen replenishment. Plus, despite
indications that attempts to run an oxygen line to the
cavern had been abandoned, there are reports that there
was at least some oxygen transferred, presumably not by
carrying in oxygen tanks, in the last few days.

George
 
> -- 
> Libor Striz aka Poutnik ( a pilgrim/wanderer/wayfarer)
> 
> "Humour is the only effective weapon against stupidity."
> Miloš Forman
> 
> 
> ----Android NewsGroup Reader----
> http://usenet.sinaapp.com/

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#693065

cornelius@eisner.decus.org (George Cornelius) Wrote in message:
> In article <phs2tm$n6k$1@dont-email.me>, Libor Striz <poutnik4REMOVEnntp@CAPITALSgmail.com> writes:
>>
>  


> 
>
>  

> 

> OK, so porosity effects do apply.  As the monsoon season
> progesses is it possible the limestone becomes closer to
> being saturated with water and less capable of bearing
> oxygen and other gases?

I do not think so. There is lot of soil separating atmosphere and
 limestone and there is lot of soil gas.
Additionally, there is diffusion of dissolved  gases into
 limedtone pores.
>  

>> 

> 

> 
> I have heard that there were later readings after the reported
> 15% O2 number and that it has climbed back up to 17%.  Perhaps
> there has been some oxygen replenishment. Plus, despite
> indications that attempts to run an oxygen line to the
> cavern had been abandoned, there are reports that there
> was at least some oxygen transferred, presumably not by
> carrying in oxygen tanks, in the last few days.
> 
There was an  explicit report one diver died along the back route
after transporting some oxygen tanks. The gas tube would be nice
 to have, but I suppose it would extremely difficult to transport
 all the length.
>  
>> -- 
>> Libor Striz aka Poutnik ( a pilgrim/wanderer/wayfarer)
>> 
>> "Humour is the only effective weapon against stupidity."
>> Miloš Forman
>> 
>> 
>> ----Android NewsGroup Reader----
>> http://usenet.sinaapp.com/
> 


-- 
Libor Striz aka Poutnik ( a pilgrim/wanderer/wayfarer)

"Humour is the only effective weapon against stupidity."
Miloš Forman


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

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#693256

In article <phs7ia$fot$1@dont-email.me>, Libor Striz <poutnik4REMOVEnntp@CAPITALSgmail.com> writes:
> cornelius@eisner.decus.org (George Cornelius) Wrote in message:
>> OK, so porosity effects do apply.  As the monsoon season
>> progesses is it possible the limestone becomes closer to
>> being saturated with water and less capable of bearing
>> oxygen and other gases?
> 
> I do not think so. There is lot of soil separating atmosphere and
> limestone and there is lot of soil gas.
> Additionally, there is diffusion of dissolved  gases into
> limedtone pores.

Thanks so much for your insightful comments.  I had hoped to
get some ideas from people in this group that understood the
issues since the authorities on the ground appeared to have
reversed themselves on the viability of leaving the team in
the cavern for an extended period and you have more than met
my expectations with regard to that.

Now that the decision has been made and they are now on their
way towards removing the second group of four boys from the
cave, I suppose this line of reasoning is now moot, but thanks
for responding with such valuable information.

George

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