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"Invisible" <voi### [at] dev null> wrote in message
news:49466678$1@news.povray.org...
> HOW THE HELL DO THEY CUT DIAMONDS?!
If you mean in the first instance when say, a large rough diamond needs to
be made into several smaller faceted diamonds, well, they 'cleave' the
rough. Basically, a hammer and chisel are used to smack a rough in half and
then quarters, etc.
But if you meant cutting the actual facets, well, with diamond of course.
;)
Actually, it's diamond paste. They start with a rough paste and work the
facets down to a smooth finish with a fine paste and then they use even
finer diamond paste (or spray) to actually polish the facets.
~Steve~
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Invisible wrote:
>
> Hee... My uncle has a 2 tonne lathe.
>
> It's big.
>
Where I used to work had a lathe 12 feet long... They used it to machine
the rollers for the presses. :)
--
~Mike
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Invisible wrote:
> You have to design a whole product to construct your product!
I always thought it was really complex, until I realized it's exactly what
you do with software. You go through and solve the problems as they come up,
and with some experience you find you rarely if ever have to go back to the
beginning because something is wrong down the line.
--
Darren New, San Diego CA, USA (PST)
The NFL should go international. I'd pay to
see the Detroit Lions vs the Roman Catholics.
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scott wrote:
> Exactly - and you begin to realise how expensive, how many people, and
> how much time it takes to design something apparently simple like a
> mobile phone. Then imagine designing something like a car, or a plane!
I've read that mobile phones are actually more complicated than commercial
jumbo jet airplanes. I don't know how that's measured, mind, but I'd be
willing to believe it. One rarely has to manage changing speed-of-light
calculations when driving a car or a plane.
--
Darren New, San Diego CA, USA (PST)
The NFL should go international. I'd pay to
see the Detroit Lions vs the Roman Catholics.
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> I've read that mobile phones are actually more complicated than commercial
> jumbo jet airplanes. I don't know how that's measured, mind, but I'd be
> willing to believe it. One rarely has to manage changing speed-of-light
> calculations when driving a car or a plane.
Don't believe it!
Just think of all the navigation and control systems in a plane (both
hardware and software), plus the fact that there needs to be 4-way
redundancy and everything must be designed to work for 30 years rather than
3 years. Surely all that has got to be more complex than a mobile phone?
And that's before you've even considered how complex a modern jet engine is,
or the retractable landing gear, the control surfaces, the control systems
to keep the plane stable, the auto-pilot etc.
I guess there's a reason why you can design a new phone from drawing board
to mass production in 18 months, but a plane takes nearer 10 years.
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scott wrote:
> Just think of all the navigation and control systems in a plane (both
> hardware and software),
Not difficult to top. I mean, heck, we used to do *that* without any
computers at all.
> plus the fact that there needs to be 4-way redundancy
As opposed to supporting several versions of CDMA and GSM, bluetooth, GPS,
HDTV, surround sound, and 3D graphics acceleration, all on one chip, running
on a tiny battery for a week at a time, talking to assorted carriers all
with their own versions of the standard implemented? :-)
I think it's certainly close.
> and everything must be designed to work for 30 years rather
> than 3 years.
I'll grant you that's a restriction you don't see on mobile phones.
> And that's before you've even considered how complex a modern jet engine
> is, or the retractable landing gear, the control surfaces, the control
> systems to keep the plane stable, the auto-pilot etc.
Again, all that was done before people even invented computers.
> I guess there's a reason why you can design a new phone from drawing
> board to mass production in 18 months, but a plane takes nearer 10 years.
People don't design phones from scratch. Certainly the first analog cell
phones were under development for some 70+ years, and digital cell phone
technology was under development for 40+ years IIRC.
(Granted, I don't think people design jet planes from scratch, either, but
that just means it's a bad comparison.)
--
Darren New, San Diego CA, USA (PST)
The NFL should go international. I'd pay to
see the Detroit Lions vs the Roman Catholics.
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>> Just think of all the navigation and control systems in a plane (both
>> hardware and software),
>
> Not difficult to top. I mean, heck, we used to do *that* without any
> computers at all.
But it's all done *with* computers today.
> As opposed to supporting several versions of CDMA and GSM, bluetooth, GPS,
> HDTV, surround sound, and 3D graphics acceleration, all on one chip,
> running
And that's just for the passenger entertainment system on-board :-)
>> And that's before you've even considered how complex a modern jet engine
>> is, or the retractable landing gear, the control surfaces, the control
>> systems to keep the plane stable, the auto-pilot etc.
>
> Again, all that was done before people even invented computers.
And they were noisy and inefficient, today they are far more complex. A bit
like comparing a car engine from today with one from 50 years ago.
Completely different and orders of magnitudes more complex today, but in
return you get a much quieter, cleaner and efficient engine.
>> I guess there's a reason why you can design a new phone from drawing
>> board to mass production in 18 months, but a plane takes nearer 10 years.
>
> People don't design phones from scratch.
Nor planes, but the typical timescale from concept to MP is a pretty good
indicator of how complex the product is.
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scott wrote:
>>> Just think of all the navigation and control systems in a plane (both
>>> hardware and software),
>>
>> Not difficult to top. I mean, heck, we used to do *that* without any
>> computers at all.
>
> But it's all done *with* computers today.
>
>> As opposed to supporting several versions of CDMA and GSM, bluetooth,
>> GPS, HDTV, surround sound, and 3D graphics acceleration, all on one
>> chip, running
>
> And that's just for the passenger entertainment system on-board :-)
>
>>> And that's before you've even considered how complex a modern jet
>>> engine is, or the retractable landing gear, the control surfaces, the
>>> control systems to keep the plane stable, the auto-pilot etc.
>>
>> Again, all that was done before people even invented computers.
>
> And they were noisy and inefficient, today they are far more complex. A
> bit like comparing a car engine from today with one from 50 years ago.
> Completely different and orders of magnitudes more complex today, but in
> return you get a much quieter, cleaner and efficient engine.
>
>>> I guess there's a reason why you can design a new phone from drawing
>>> board to mass production in 18 months, but a plane takes nearer 10
>>> years.
>>
>> People don't design phones from scratch.
>
> Nor planes, but the typical timescale from concept to MP is a pretty
> good indicator of how complex the product is.
The main difference I'm noticing is that... mobile phones aren't safety
critical.
I don't even wanna *know* what kind of tests a plane has to pass...
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