Somewhat OT: Long term design
in [Design]
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From: Michael A. Terrell on 15 Jan 2010 17:56 Tim Williams wrote: > > "Michael A. Terrell" <mike.terrell(a)earthlink.net> wrote in message > news:4B50D385.EEBFBB4D(a)earthlink.net... > > How can your DNA tell them what's in your mind? :) > > How can your anus? > > (Except for those with slomanitis. ;-) ) That depends on how far they probe. Those bumps on their skulls say it all. ;-) They have to use the 'big probe' on Sloman, the regular size falls out. :( -- Greed is the root of all eBay.
From: Michael A. Terrell on 15 Jan 2010 17:58 WangoTango wrote: > > In article <4B50D385.EEBFBB4D(a)earthlink.net>, mike.terrell(a)earthlink.net > says... > > > > John Larkin wrote: > > > > > > On Fri, 15 Jan 2010 12:23:35 -0500, "Michael A. Terrell" > > > <mike.terrell(a)earthlink.net> wrote: > > > > > > > > > > >John Larkin wrote: > > > >> > > > >> The stupid TV shows just need villains to add drama. All the aliens > > > >> that I've met were actually very nice. > > > > > > > > > > > > Don't you get tired of being probed? ;-) > > > > > > Another SyFy channel slander. Any reasonably intelligent alien can nab > > > a bit of DNA from your fingerprint and know everything about you. > > > > > > I don't watch SyFy channel. It's not availible on sub-basic cable. > > > > How can your DNA tell them what's in your mind? :) > > That must be one hell of a probe.......ouch. I wouldn't know. I've never been probed. :) -- Greed is the root of all eBay.
From: krw on 15 Jan 2010 19:38 On Fri, 15 Jan 2010 13:08:56 -0500, "Michael A. Terrell" <mike.terrell(a)earthlink.net> wrote: > >Tim Williams wrote: >> >> "Michael A. Terrell" <mike.terrell(a)earthlink.net> wrote in message >> news:u_qdnXBdCJE8Oc3WnZ2dnUVZ_hti4p2d(a)earthlink.com... >> >> The stupid TV shows just need villains to add drama. All the aliens >> >> that I've met were actually very nice. >> > >> > Don't you get tired of being probed? ;-) >> >> All the ones he's met used lube. ;-) > > > Or a mind wipe? ;-) Do that on DimBulb and it'll come back brown.
From: Joerg on 15 Jan 2010 20:54 Phil Hobbs wrote: > On 1/14/2010 12:58 AM, Joerg wrote: >> John Larkin wrote: >>> On Thu, 14 Jan 2010 15:51:25 +1100, Sylvia Else >>> <sylvia(a)not.at.this.address> wrote: >>> >>>> Joerg wrote: >>>>> John Larkin wrote: >>>>>> On Thu, 14 Jan 2010 13:31:08 +1100, Sylvia Else >>>>>> <sylvia(a)not.at.this.address> wrote: >>>>>> >>>>>>> A recent episode of Stargate Atlantis prompted me to think about >>>>>>> how would could design equipment that's intended to function far >>>>>>> into the future. The episode required stuff to function 48,000 >>>>>>> years after construction, but perhaps we could be less optimistic. >>>>>>> >>>>>>> Say 1000 years. >>>>>>> >>>>>>> Note, the requirement is not that the equipment function *for* >>>>>>> 1000 years, but that when it is turned on, 1000 years from now, >>>>>>> that it will work. >>>>>>> >>>>>>> It seems to me that semiconductors are out due to effects of >>>>>>> difusion and radiation. >>>>>>> >>>>>>> But how about thermionic valves? They're not very reliable, but do >>>>>>> they age when not in use? Would they hold a vacuum over that time? >>>>>>> >>>>>>> Obviously electrolytic capacitors are a no-no, but can resistors >>>>>>> and capacitors be made stable enough that they'd work? >>>>>>> >>>>>>> Would it help to enclose the entire circuit in a vacuum tube? >>>>>>> Again, could the tube sustain the vacuum over such a period? >>>>>>> >>>>>>> An energy source is a problem. Perhaps a cell where acid is added >>>>>>> (how?) at the appropriate time? >>>>>>> >>>>>>> Sylvia. >>>>>> I'd expect that most semiconductors and passives would last 1000 >>>>>> years, given a conservative design. There's not much radiation around >>>>>> at sea level. The gadget could be stored in vacuum or dry nitrogen to >>>>>> prevent corrosion and wiskers and such. >>>>>> >>>>>> It shouldn't be hard to keep a vacuum tight for 1000 years. A decent >>>>>> flange-sealed vacuum vessel hardly leaks at all. If it can do 1e-12 >>>>>> torr for a minute, it leaks to atmosphere in (linear extrapolation) 2 >>>>>> billion years. >>>>>> >>>>>> I think solar cells would stand up well. I bet that a Casio solar >>>>>> calculator will work 1000 years from now if properly stored. The >>>>>> biggest hazard would probably be polymerization of the plastics in >>>>>> the >>>>>> keypad, or maybe leakage from a poorly sealed LCD. >>>>>> >>>>>> I still use my original HP35 calculator, purchased in 1972. >>>>>> >>>>> HP11C over here. I still use my grandpa's drill from around the >>>>> 1920's. Works fine. You just have to keep the grease reservoirs >>>>> packed by tightening the caps once in a while and refilling when at >>>>> the peg. >>>>> >>>>> Oh, and the church we were married at goes back about 1200 years, >>>>> the organ in there is probably well past 500 years. I guess a pipe >>>>> organ fulfills the definition of "equipment". It can be done. >>>>> >>>> Well, I'm not sure the organ qualifies, even if it reaches 1000 >>>> years. Has it never been repaired? >>>> >>>> The requirement is that the equipment be built, be left untouched for >>>> 1000 years, and then work. >>>> >>>> Sylvia. >>> >>> Reliability folks generally assign component failure rates in FITs, >>> namely one failure per billion hours. Most passives have numbers near >>> 1 FIT, and lots of semiconductors are in the single digits. >>> So a 100-part gadget that uses average 1 FIT parts will have an MTBF >>> of 1e7 hours, a bit over 1000 years. That assumes the parts have no >>> wearout mechanism. In practise, field failure rates can be quite a bit >>> better than specs like MIL-HBK-217 or Bellcore predict, ie better than >>> 1 FIT average per part. >>> >> >> In Europe the problem with much of the Roman stuff was that there were >> usually 5-10 fierce wars over a period of 1000 years. That kind of puts >> a crimp into the MTBF. >> > > Your part of Europe was obviously quieter than most. ;) > Well, I meant the real serious wars where vast stretches of land go up in flames or wild hordes destroy everything in their path. They always had the little spats between individual fiefdoms. For example, Germany wasn't really a country until "recently". -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Sylvia Else on 16 Jan 2010 00:06
Robert Baer wrote: > Sylvia Else wrote: >>> George Herold Inscribed thus: >>> >>>> On Jan 13, 9:31 pm, Sylvia Else <syl...(a)not.at.this.address> wrote: >>>>> A recent episode of Stargate Atlantis prompted me to think about how >>>>> would could design equipment that's intended to function far into the >>>>> future. The episode required stuff to function 48,000 years after >>>>> construction, but perhaps we could be less optimistic. >>>>> >>>>> Say 1000 years. >>>>> >>>>> Note, the requirement is not that the equipment function *for* 1000 >>>>> years, but that when it is turned on, 1000 years from now, that it >>>>> will work. >>>>> >>>>> It seems to me that semiconductors are out due to effects of difusion >>>>> and radiation. >>>>> >>>>> But how about thermionic valves? They're not very reliable, but do >>>>> they age when not in use? Would they hold a vacuum over that time? >>>>> >>>>> Obviously electrolytic capacitors are a no-no, but can resistors and >>>>> capacitors be made stable enough that they'd work? >>>>> >>>>> Would it help to enclose the entire circuit in a vacuum tube? Again, >>>>> could the tube sustain the vacuum over such a period? >>>>> >>>>> An energy source is a problem. Perhaps a cell where acid is added >>>>> (how?) at the appropriate time? >>>>> >>>>> Sylvia. >>>> What does the machine have to do? Mechanical stuff (gears, cams, >>>> punch cards) lasts a long time. It could be powered by gravity. >>>> >>>> George H. >> >> Well, if way take the TV program as an indication, and including my >> own interpretation of what happened (which wasn't that clear). >> >> It appears we need a radio receiver on some frequency that will be >> turned on after some number of thousands of years, and then run for >> perhaps one hundred years. If it detects a radio signal, it has to >> start up a computer, which is connected to a transmitter on that same >> frequency. The computer doesn't have to run continuously, but has to >> be able to run intermittently for a further thousand years. The >> transmitter is not required to be able to run for more than a few >> hours once turned on. >> >> There was also a signficant power supply that could be turned on after >> 48,000 years, and then actually run for a further 1000. I had thought >> this was a big ask, but perhaps not. U235 has a half life of 700 >> million years, but is clearly usable to produce power in nuclear >> reactors. >> >> I suspect that building a computer that would still be functional >> after even the first 1000 years would be a challenge, even if it were >> not running during that time. >> >> Sylvia. >> >> >> >> >> > <grumble>.."functional"..guess one better start to define (nominal) > capabilities of that computer first. That's a problem, in as much as the TV show had the computer (which wasn't actually mentioned, or was referred to as a "core drive"), housing a human personality. I wouldn't know where to start in terms of defining its capabilities in a way that would make engineering sense. Indeed, it may not be possible, even in principle. Sylvia. |