Somewhat OT: Long term design
in [Design]
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From: JosephKK on 16 Jan 2010 07:50 On Wed, 13 Jan 2010 18:48:33 -0800 (PST), George Herold <ggherold(a)gmail.com> wrote: >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. Indeed, consider the traps in ancient tombs.
From: Michael A. Terrell on 16 Jan 2010 08:05 JosephKK wrote: > > Indeed, consider the traps in ancient tombs. The original 'lint' traps? ;-) -- Greed is the root of all eBay.
From: Nico Coesel on 16 Jan 2010 08:27 Robert Baer <robertbaer(a)localnet.com> wrote: >John Larkin wrote: >> 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. >* Sorry, NASA has seen whisker growth in their satellites.. If it needs to be reliable solder is out of the question. Just look at automotive electronics. The really reliable stuff is (sort of) spot welded and covered with some sort of goo. Other ways are wire-wrap, press-fit and crimping. -- Failure does not prove something is impossible, failure simply indicates you are not using the right tools... nico(a)nctdevpuntnl (punt=.) --------------------------------------------------------------
From: JosephKK on 16 Jan 2010 08:32 On Wed, 13 Jan 2010 21:54:46 -0800 (PST), a7yvm109gf5d1(a)netzero.com wrote: >On Jan 14, 12:45 am, John Larkin ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >> On Wed, 13 Jan 2010 21:30:33 -0800 (PST), a7yvm109gf...(a)netzero.com >> wrote: >> >> >> >> >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? >> >> >Oh, they can be made very reliable. They can be accelerated at 100Gs >> >and used in proximity fuzes (note the spelling), as in WWII; >> >> 20,000 Gs! >> >> John > >Yeah, even worse! I was probably thinking of this toy >http://www.youtube.com/watch?v=nLpLEgAS574&feature=related > >I guess an artillery shell leaves in even bigger of a hurry, but >doesn't *keep* accelerating... More of a "jerk" situation? Well an 8 inch 58 military cannon accelerates an approx 100 lb projectile to about 3000 ft/s in some 22 feet. The acceleration curve looks kind of like a truncated "F" distribution.
From: Nico Coesel on 16 Jan 2010 08:30
"Tim Williams" <tmoranwms(a)charter.net> wrote: >"John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message >news:3mbtk55eiaskjbllse9ceknp3lblra9tal(a)4ax.com... >> Aluminums fail by drying out, through water vapor leakage through the >> rubber seals. That's a wearout mechanism. > >Al Po's? > >Generally considered as good as tantalum and fairly indestructible, aren't >they? Kind of new to use for millenium hardware though. Tantalums are very prone to failure. I avoid them if I can. Even electrolytics are better because they don't cause a short. Nowadays I use the MLCC capacitors where I can. -- Failure does not prove something is impossible, failure simply indicates you are not using the right tools... nico(a)nctdevpuntnl (punt=.) -------------------------------------------------------------- |