Re: 1teraflops cell processor possible?

del cecchi wrote:
> "Nick Maclaren" <[EMAIL PROTECTED]> wrote in message
> news:[EMAIL PROTECTED]
>
> > In article <[EMAIL PROTECTED]>,
> > Russell Wallace <[EMAIL PROTECTED]> wrote:
> >
> > > On 28 Nov 2003 17:57:05 GMT, [EMAIL PROTECTED] (Nick Maclaren)
>
> wrote:
>
> > > > Aluminium forms a thin skin of alumina (the oxide) when exposed
> > > > to oxygen, or oxygen and water, and thus is rustproof in fresh
> > > > water.  However, it is VERY badly attacked by salt water, and
> > > > sailing boats etc. that use aluminium spars protect them by
> > > > anodisation (however that works).  Even with that protection,
> > > > which may or may not be application to aircraft, one of its normal
> > > > failure modes is through corrosion.
> > >
> > > Ah! Interesting.
> > >
> > > Any idea why they used it for warships, then?
> >
> > It's 3 times lighter than steel, so you can put much more junk
> > on the ship and not have it turn turtle the first time there is
> > a bit of a blow.

At least in the US Navy, the use of aluminum as a major structural 
element on warships was abandoned years ago, largely as a result of the 
British experience in the Falklands, IIRC. (when a warship is hit, it's 
almost inevitably going to have major fires, and when much of the 
superstructure is aluminum, it starts to melt and then burn. It makes 
damage control problematic, to say the least)

> > > Also, if you know an aluminium object is going to be immersed in salt
> > > water, why doesn't a layer of waterproof paint solve the problem?
> >
> > It chips and cracks in use, especially near moving parts.
>
> It apparently depends greatly on the aluminum alloy that is used.  Many
> aluminum boats are used in salt water.  They are not anodized.  Neither
> are the aluminum masts.  The problem with airplanes is that they were
> not designed for nor tested to withstand salt water immersion.  And it
> is probably really hard to wash the salt off to make sure nothing bad
> happens 10 years down the road.

If you think about all the things _in_ an aircraft that would need to be 
torn out and replaced, plus needing the entire stucture opened up and 
thoroughly washed out with fresh water, it almost certainly would be 
much cheaper to simply buy a new aircraft. There are seaplanes built to 
operate in on saltwater, but even they would scrapped if they sank in 
salt water, I think (unless they're irreplaceable for some reason). For 
naval aircraft, especially carrier-based, corrosion control due to 
salt-spray is truly a major concern.

--Larry