[Olpc-open] some questions...

[Xavier Alvarez]

On Saturday 20 January 2007 16:35, Kevin Purcell wrote:
KP> This is standard boiler plate for environmental testing of
KP> electronics hardware. Check your favorite device ... it will
KP> have these heights mentioned.

I know... it's just that since the laptop is intended to reach 
''the remotest places''... high places are usually an 
after-thought - boiler-plates just prove it... ;)

KP>
KP> It comes from work like this "Hypsographic demography: The
KP> distribution of human population by altitude"
KP>
KP> <http://www.pnas.org/cgi/reprint/95/24/14009.pdf>
KP> 
<http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=24316&tools=bot>

Interesting site! Thanks!

KP>
KP> > The global distribution of the human population by
KP> > elevation is quantified here. As of 1994, an estimated
KP> > 1.88 × 109 people, or 33.5% of the world’s population,
KP> > lived within 100 vertical meters of sea level, but only
KP> > 15.6% of all inhabited land lies below 100 m elevation.
KP> > The median person lived at an elevation of 194 m above sea
KP> > level. Numbers of people decreased faster than exponentially
KP> > with increasing elevation. The integrated population density
KP> > (IPD, the number of people divided by the land area)
KP> > within 100 vertical meters of sea level was significantly
KP> > larger than that of any other range of elevations and
KP> > represented far more people. 
KP>
KP> Or to pick say a potential target country (China) at random
KP> from the net as it has some decent how mountains and
KP> plateaus and a quarter of the world's population.

According to your link, there are 10 million chinese living on 
that section of the world's roof... assuming 30% under age 18, it 
gives around 2.8 million kids up there... more than half what the 
OLPC needs to launch. Add India, the Andean highplateau and you 
could probably set shop just targeting them... ;)

KP>
KP> 
<http://www.iiasa.ac.at/Research/LUC/ChinaFood/data/pop/pop_14.htm> 
KP>
KP> 0.9% of the population of China live at an altitude of over
KP> 3000m. Whereas 33% of the world population live within 100m
KP> of sea level. 
KP>
KP> I wouldn't worry about it. The XO isn't going to magically
KP> cut out at high altitude.
KP>
KP> So long as the air pressure is high enough to maintain
KP> convective cooling of the device it will keep working when
KP> you are having problems breathing at 5531m (the highest
KP> permanent habitation on the planet).

Having lived in La Paz (at 3600 mts) I can testify that things can 
work 'just fine' at that altitude - and higher; but having a 
boiler-plate could imply that no real thought or tests have been 
made on the issue...

BTW, the main reason why you have problems breathing at 5531m IS 
air pressure... or rather, lack of it. Compounded by the lack of 
red blood cells in a non-climatized body that spends a lot of 
energy -thus oxygen- just moving the thin air in and out of the 
lungs, and your heart trying to pump enough blood through them to 
compensate...

Altitude raises a whole set of problems. Typically people refer to 
breathing, headaches and low water boiling point... then you have 
to add ultra violet A/B, thermal amplitude (cold is a battery 
killer - hopefully constant cranking/pedaling will help the child 
stay warm and fit while reading ;) humidity (actually lack of it, 
which is for electricity is generally good - until you get static 
discharges), and many other 'ailments' including chances of 
infertility due to high-flying trans-polar flights... ;)


Cheers,
Xavier

KP>
KP> On Jan 20, 2007, at 9:02 AM, Bipin Gautam wrote:
KP>
KP> > 1). I read in the laptop hardware specification
KP> > Altitude: -15m to 3048m (14.7 to 10.1 psia) (operating)
KP> >
KP> > so the laptop ISNT designed to operate over 3048m height
KP> > and doing so will void all warenties?
KP>
KP> --
KP> Kevin Purcell
KP> kevinpurcell at pobox.com
KP>
KP>
KP> _______________________________________________
KP> Olpc-open mailing list
KP> Olpc-open at laptop.org
KP> http://mailman.laptop.org/mailman/listinfo/olpc-open
KP>

-- 
XA
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