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Re: Engineering Newsletter
Timothy replies to Kevin:
>> Reading the kind of English that you guys write is not too difficult so I
>> can almost always manage without any help.
>
>I'm not sure if that is a compliment or a put-down ;)
I'm not sure either :)
>> Yes a radius of 580 kilometre, but would it not become too hot? (the
>> radiation level is about 10000 Watt/m^2)
>
>I think the heat could be kept below the melting point of silicon. As
>the Temperature goes up, so does the blackbody radiation.
But since the doped silicon is quite temperature sensative 100 degrees extra
may have a bigger effect than you would expect.
>> >> That would always be anti-matter or a beam that is very tight.
>> >
>> >i don't agree, that's true only if you want to do it in a man's
>> >lifetime. if you are willing to accept a lower speed, then you can do
>> >the trip with a _lot_ less energy.
>>
>> The the answer is also easy, with one Joule you could come everywhere. (live
>> support not included ;) )
>
>
>That reminds me of a great new travel method making use of Hiesenberg
>Uncertainty principle: as Temperature approaches Abs Zero, Momentum
>becomes zero to the last decimal, and the position becomes _infinite_.
It is not the position that becomes infinite but the PROBABILITY of its
position that becomes infinite. May look the same, but is different. The
chance to find the particle at a particular place in the universe will be
almost zero, but the chance to find it in space as a total stays equal to
one. So effectively you won't know where your particle is after you cooled
it down to absolute zero.
The fact that a particle can move lightyears be everywhere is As you can
see, this Although this may look as if it is conflict with the finite speed
of light there is a deeper understanding that solves this "paradox".
>the recent cooling of some atoms down to nanokelvins of Abs Zero, makes
>me hopeful that this might someday work. although how you go from room
>temp to even a "balmy" -40 (celsius, Farenhiet, what's the diff. ;) )
>is another question, but if you could make to that emp and survive, then
>perhaps you could make it to Abs Zero.
If it can be reached, than it's unlikely tha
>Solid yes. Metal, no. at one atm, hydrogen becomes an ice-like solid,
>which does not have any free electrons. only at great pressures
>(ie Jovian core) does the hydrogen take on any metallic properties.
I didn't know that, do you know a subject or book about that, where I can
search for in a library?
>> Yes, I proposed that idea some weeks ago.
>
>Oops, musta missed that one.
It was in the long and dreary letters I wrote Kelly ;)
>one robot may not be able to replicate in three days, with out some
>minimum number of "support" units, to mine ore, cart raw materials to
>easy places etc etc
OK.
>> (Note: Probably all robots will be worn out after a few years, so you may
>> need 3 or 4 times more than you originally would think, that would only cost
>> a few days extra)
>
>Any robot could probably repaired far cheaper than it could be re-built
>from scratch, and this could be done at any time, not just at the outset
Repairing is rather difficult, for some dumb replicating machine it is
probably much easier to make a new one than to look for the non-working part
and replace it. It is just like a conveyer belt, there is a gain because of
the repetative task.
>i think TCP/IP would be much better suited to robotic units than to humans
1E13 adresses need about 42 bits that's 10 bits more than the current URL/IP
needs :)
>This is where you have some robots dedicated to the task of routing. if
>each robot has a long-range low-bandwidth transmitter (to call for help,
>or report on distant conditions) and a high-bandwidth short-range (10m?)
>transmitter, then there should not be too much radio interferance. As
>for physically bumping into each other, one robot in 1024 could be
>dedicated (aside from it's router duties) the task of "traffic control",
>telling two robots when they get too close to each other (say within two
>meters)
I hadn't thought of the short and long range possibility, that would be a
good solution.
>in thinking about this, i was struck by the comment you made about the
>radius of the solar collector being about the same as the face of the
>moon, and i thought, what if instead of putting it (the collector) in
>orbit around the sun at Mercury's distance, why not just cover the
>surface of mercury with solar panels? (not too difficult if you have
>self-replicating robots) They could exist underground safely, and the
>maser array could be placed on the south pole of mercury (TC is below the
>ecliptic) Mercury would provide more than enough counter-weight for the
>beam, and the low gravity would assist the robots in maintaining the arrays
Yes, that would also solve the problem of the solar-panels and laser-array
being blow away by the photon pressure. A problem still present, is that the
laser-array has to be directed, wich may be a problem on a rotating planet.
>> Computer circuits mostly need semi-conductors, so I think super-conductors
>
>Ever hear of a Josephson <sp?> junction?
Yes, but as far as I know a Josepson junction has nothing to do with
transistor like properties. (Or am I mistaken?)
(What does <sp?> mean?)
>> may not work there. But the other applications may be useful. Oh by the way,
>> super conductors can't conduct infinite currents... I don't know what their
>> maximum is though, I asked someone who worked with them but he didn't know
>> either, they used only small currents and small pieces.
>
>yes, i knew that, but that may be a limitation of technology, or is it
>fundamental?
It is fundamental, it is limited by the paramagnetic energy of the
electrons. If too many electrons are moving, the special conditions are
distroyed and superconduction is lost. I looked through some books and found
that the maximum magnetic field possible for a certain superconductor with
Tc=20K was 36 Tesla (Probably enough) But I still don't know the maximum
current.
The field would be have the same value at 1 cm distance from the center of a
wire that conducts 350 Ampere. (rough approximation).
>Keivn
Is that your name in phonetic language? :)
Timothy