Re: [Paddlewise] Waterproof Binoculars -Reply

Jim Martin wrote:

> Air is 79 mole % Nitrogen. Therefore air has properties roughly portional
> to 79% of nitrogens properties.  Actually Nitrogen has a very low heat
> capacity therefore it's pressure will be affected by heat input slightly
> more than air. A given heat input will increase the temperature of Nitrogen
> slightly faster than air as a result the pressure will also increase slightly
> faster at a given heat input. This may be the actual reason Indy cars
> (assuming they do) use nitrogen. They will reach steady state, thermal
> equilibrium, faster. Therefore after the tires will reach a steady
> performance level faster. It may also be to prevent oxidation of the rubber
> on the inside of the tire at high temperatures. Remember that different
> rubbers are used from the inside to the outside of the tire. All I can tell you
> for sure is that Nitrogen will react to heat slightly more than air.
>
> ------------------------------------------------------------------------
>
>

I take the side of understanding that Nick Schade offers. The airline industryuses
nitrogen gas to maintain constant tire pressure. Being that the molecules
of nitrogen are larger they maintain that pressure whereas air molecules being
smaller are able to permeate the rubber membrane or tire casing more readily.
Companies that transport (18-wheelers ) liquid Oxygen have their transport
tires filled with nitrogen for safety reasons (being that nitrogen is more inert).
When the big jets touch down onto the tarmac of the runway they get very hot
and the stability of nitrogen increases tire life and reduces risk of blow-out.
The cash savings rests an estimated 25 per-cent wear in the tires. Now when you
own a fleet of Jet Airliners twenty five percent life expectancy increase
translate into a significant amount of money. According to one popular
science and mechanics issue temperature plays an important role and reason
for using nitrogen. After all it is the money and safety that is being realized.

I have owned a pair of "BRUNTON" Binoculars for several years. Of course
they are nitrogen filled and ruby lens coated for UV reduction. THey have
performed marvelously in 30 below weather as they have along the ocean
in hot weather and rain. I think Brunton's are great.


> Cheers,

Philip Wylie

> >>> Nick Schade <schade_at_guillemot-kayaks.com> 08/27/98 02:21pm >>>
> At 7:00 AM -0500 8/27/98, M. Lenon wrote:
> <snip> and does not react to temperature
> >changes, thus maintaining an even pressure.  (In motorsports, Indy cars,
> for
> >example, use nitrogen in their tires, rather than air. That way, hot or cold
> >tire temperatures do not affect the inflation pressure because the
> nitrogen
> >doesn't expand when the tires are running at their normal 200+ degrees
> >operating temperature. Tire pressure greatly affects handling. Neat,
> huh?)
>
> Whatever happened to PV = nRT. I thought this applied to all gases. If the
> temperature goes up, either the volume has to increase or the presure
> does.
>
> Nick Schade
> Guillemot Kayaks
> c/o Newfound Woodworks, 67 Danforth Brook Rd, Bristol, NH 03222
> (603) 744-6872
>
>



***************************************************************************
PaddleWise Paddling Mailing List
Submissions:     paddlewise_at_lists.intelenet.net
Subscriptions:   paddlewise-request_at_lists.intelenet.net
Website:         http://www.gasp-seakayak.net/paddlewise/
***************************************************************************