(TFT) RE: Heat and temperature

[Mark Tapley <mtapley@swri.edu>]

At 16:26 -0400 5/8/10, George wrote:
> I kind of wish that it was explained to me this way a quarter of a century
> ago, when I was struggling with thermo & physics.

Thanks! Hope it helps. As the erudite Miss Tapley is likely still 
reading and has a Physics SAT coming up, I figured I'd just try to 
sneak in a little educational material...

At 16:26 -0400 5/8/10, Jay wrote:
> 1 cubic foot of air is VERY roughly 0.075 lbs or a little more than an ounce
> per square which is approaching 5 lbs of air per cubic square hex.

Wikipedia says approximately 1.2 kg/m^3 (sea level, 20C, yeah, yeah, 
OK). Not sure I got my conversions right, but if I did, I agree on 
the 0.075 lbs/cu.ft. .

How big is a "cubic square hex"? How tall is a hex?

If your 16 one-foot squares equate to one hex, that's about 1.219 
meters x 1.219 meters. I'll somewhat arbitrarily say 3 meters tall 
(just under 10 feet, one floor in a building ?) so each hex is 4.459 
m^3, containing 5.35 kg of air, or about 11.78 lbs.

I'm afraid you may be working with fairly low ceilings, if there's 
only 5 lbs. of air in a hex.

At 16:26 -0400 5/8/10, Jay wrote:
> ST is the amount of energy available to a well rested, fed and healthy
> Figure.
> fST is the rate at which the Figure spends its energy... power nie?
>
> I also use a figure called pST for 'passive' ST.

OK on ST - means how much work a figure can put out before it *has* 
to eat or die. This would be a little flexible - I think the body can 
convert muscles, etc. after all the carbs and fat runs out - but it's 
not a good thing for the person involved.

fST I think is *way* trickier. I think of fST as more like Oxygen 
deficit - work hard for a few minutes, take a several minute breather 
to re-saturate oxygen in your muscles, do it again.

I think it doesn't even relate linearly to power, unfortunately, 
because the body more or less works on two cycles - anaerobic and 
aerobic. Aerobic work, you can keep up all day - the Tour de France 
guys can put out about 0.25 kW for hours on end that way. That digs 
into their ST, no doubt, and they have to eat like horses at the end 
of the day to replace all the calories - but they are not showing 
oxygen debt during it ....

... *except* during the sprints. When you exceed your aerobic 
threshold, you start switching to anaerobic metabolism. That, you 
cannot maintain for long, but you can get higher power levels. Maybe 
up to 0.4 kW or so? But there's a price - you lower your oxygen 
saturation, waste products build up, and you basically *have* to quit 
before long. Recovery takes a long time for this. I suspect most 
melee combats are fought with the participants deep into this 
anaerobic cycle, and therefore the fST really is an appropriate 
measure of endurance for this.

Dunno why magic takes anaerobic metabolism, but I'm sort of pushed 
toward this conclusion.

Passive ST, agreed mostly but you have some tough eggs if they are 
good for 20 pST in any direction.


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						- Mark     210-379-4635
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