"Forgotten" technologies

[kengr]

For folks writing or gaming in situations where people might encounter long forgotten (or hidden) installations there are several technological bits that would make fun additions.

First off, our old friend TIMMs. Thermally Integrated Micro Modules.

These were blocks of ceramic and high temp metals. They were developed after EMP was discovered as something that could survive EMP bit still not be much bigger than the then current gear that used printed circuits with individual transistors and the like.

They were tube based, but the tube were the size of a dime. and the units were a solid block of metal and ceramic except for the cavities that were the vacuum inside the tubes or the filling of capacitors.

The didn't have filaments for the tubes, so that eliminated one common source of failure in tube based equipment. Instead the blocks were placed in what amounted to a well insulated oven and heated to a dull red heat which got the cathodes hot enough to work.

These would be great for gear in the stereotypical volcano lair or around a big nuclear reactor.

Next, if you encounter a *really* old installation (say 1890s to 1920s) you may encounter radio transmitters (morse code only, not voice) that don't use tubes. Instead they use an alternator (a sort of AC generator) to generate the signal.

Another fun thing are radon bulbs. Used for emergency lighting, they are glass globes or other shape, The inside is coated with a phosphor much like the ones used in fluorescent lights. They are filled with radon gas, and the particles emitted by the decaying radon strike the phosphor coat and produce light.

You could probably make some something similar with other radioisotopes, but radon is what was used in the ones I've read about.

"Gee, how are these lights still working? They're a bit dim, but..."

"Wait a sec. Look at how they are mounted. There aren't any wires..."

Just the thing to creep out the radiation averse. :-)

(added later)

Oh yeah, refrigeration gear. Before freon was invented commercial refrigeration used 3 different easily liquified gases as working fluid: Chlorine, ammonia and sulfur dioxide.

all of these are toxic. and they meant leaks were a *really* bad thing. Which is why home refrigeration didn't take off until freon came along.

Note that they are *still* used to some extent in commercial plants.

Comments

[warriorsavant]

How much of this is real?

[kengr]

All of it.

The integrated circuit pretty much killed TIMMs, though I think they'd *still* be a good idea for some jobs (Venus landers, for example).

The alternators bit is an oft overlooked bit of radio history. They'd have 100 or even thousand watt alternators running at say 600 kilocycles and they'd "key" that (now that's some switching gear *I* wouldn't want to deal with!)

With the advent of tubes, there were better ways to do it.

and yes, the radon bulbs existed. One of those ideas from the late 40s/early 50s that sounded good at the time but....

They weren't hugely bright to start with, but were ok for emergency lighting in a tunnel or something. and, of course they got dimmer as time went on (though radon has a decent half-life)

These days? I'd mix the phosphor with a strong alpha or beta emitter with a reasonable half life and embed it is something strong but transparent. But the NRC would have fits.

[siliconshaman]

There are also Tritium tubes although as you say, they're not too bright.

There is also betavoltatic batteries, basically beta-particle powered solar panels. Depending on the type of isotope, those have a half-life of 50, 100 or 1000 years. They're solid state, very stable and provide a decent voltage for a looooong time. I've seen versions that use aluminium/phosphor bronze terminals because copper corroded too much over the time span!

I have also seen a design for TIMM's that uses a thermal radioisotope to heat the cathode. Basically, a tiny hot spot of Plutonium under the cathode, heating it up locally. I have no idea if it was ever built, but it was intended for very long duration deep space probes back in the 70's.

[kengr]

Heck, they use tritium for a lot of "glow in the dark" items these days.

For far future SF (like Traveller) I've always thought that RTGs are a great power source for settlers on frontier worlds. Dif a hole, drop it in, and you've steady (if slowly decreasing) power for decades. No muss, no fuss.

And as I said above, I think they *really* should look into TIMMs for venus landers.

[siliconshaman]

Agreed on that, I mean, they're practically built for it. You could actually save power by turning the heaters off once you're down.

Problem is, I'm not sure anyone really wants to investigate Venus that much. Which is a bit short sighted all things considered. Ironically, Venus might be more inhabitable than Mars, [as long as you stay at a certain altitude]. With a breathable if smelly atmosphere and enough of it to stop solar radiation from frying your genes.

Cloud cities yo!

[kengr]

What heaters? If I was designing it, I'd have them TIMMs stuff be uninsulated so it'd be up to running temp about the time the heat gets to thne conventional electronics.

A TIMMs video camera would be an interesting challenge.

Oh yeah, sodium/sulfur batteries for power.

[siliconshaman]

Hell, you could use a liquid sodium flow battery!

Hmm.. I think I saw an early design for a charge-couple device that had an operating temperature of +400 or so, pretty big bug on Earth, kind of more a feature on Venus.

and yeah, heaters... so you can use the TIMMs on the way down by pre-warming them. Thus, no interruption of operation.

[mdlbear]

And of course there were spark-gap transmitters as well. Other amusing items:

• mechanical rectifiers: basically a DPDT switch driven by a 3600RM motor.
• flywheel "capacitor" (for experiments involving sending enormous currents through a 1-turn copper coil -- you get a really high magnetic field for a few milliseconds before the coil either melts or explodes. Or both) The one I heard about was a 16-ton concrete flywheel; I don't remember the RPMs, but it took several days to spin up and stopped in a quarter of a turn.
• magnetic-core logic. That's another that will stand up to pretty serious doses of radiation, but I don't think it would handle EMP very well.

[kengr]

I can't recall the term for those flywheel things. But they are used a lot for stuff that needs brief *massive* power surges.

I've got a 256 byte core plane not 5 feet from me. It's the same size as a 5.25" floppy (in fact, it's stored with some)

It'd take a massive EMP to effect the core plane. More likely to have problems from the induced currents in the rest of the computer.

I also have a magnetic bubble "experimenters kit" that Intel used to sell. I think it's 256k or so.

[siliconshaman]

Also magnetic core memory is easy to shield from EMP... aluminium foil and a ground wire. That's where the idea of tin foil hats came from.

[stickmaker]

These are fun. One variant is the homopolar generator:

https://www.google.com/search?q=homopolar+generator&oq=homopolar+generator&aqs=chrome..69i57j0l7.6651j1j7&sourceid=chrome&ie=UTF-8

[kengr]

You can also run that trick backwards. A rotating magnetic field will induce motion in a conductive disk.

Since there are ways (using coils carrying difference phases of a multiphase power source) of getting a rotating magnetic field from a stationary set of coils, this could make an interesting motor design.

[stickmaker]

Years ago I asked some technically-adept SF fans I know how you would design a "forever" emergency light. The limitation on those which use phosphors to transmute other radiation into visible light is that the phosphors eventually degrade. (Part of the reason the Pioneer and Voyager probes are losing power is the degradation of the heat engines. The PU-238 heat source used in their radio-thermal generators has a half-life of 88 years.)

Part of the problem with making a forever light is that very few radioactive materials glow on their own, so they need phosphors. Most of those currently used - even with phosphors - have short half-lives (for example, the half life of radium-226 is around 1,600 years; tritium is around a piddling 12 years). So you need a durable, probably non-crystalline phosphor efficient for the type of radiation the source gives off. It can be done. There is actually a lot of reference material out there for self-luminous signs. However, those are only rated in years and not millennia. Something lasting thousands of years would likely require quite a bit of materials research, if only to make sure nothing dangerous is likely to escape.

As for working while red hot, for really hot operating conditions you probably want ceramics. Adolph Coors, besides making beer, have long had a business of making laboratory-grade ceramics. Back in the late-Fifties to early-Sixties they were involved in a project to produce a half-gigawatt, air-cooled fission reactor. They developed pneumatically-operated, ceramic actuators designed to operated while white hot. The government reactor project was cancelled before completion, but today the descendants of those actuators are still used in some steel mills.

Which gives me the mental image of fluidic circuits in ceramic media operating somewhere very hot.

[kengr]

The long term problem with using radioactive decay to power a light is that the power output is inversely proportional to the half-life.So you quickly reach a point where merely having a phosphor and radiation source won't cut it.

At that point you need something like an electroluminescent panel powered by some sort of RTG or the like. That way you have a much bigger ratio of radioactives to light source.

TIMMs do use high temp ceramics. They also used a 3D parts layout. So you had this brick of ceramic and high temp metals with contacts on the surface.

Very much "solid state" circuitry. :-)

Reminds me of the discussions on the TML (Traveller Mailing List) about players finding derelict spacecraft. If they are *old* (centuries, rather than decades), you start running into "interesting" problems.

Due to diffusion of atoms, you get vacuum welding of things in contact. Even if the vacuum isn't that good. You also get semiconductor based devices that no longer work because the dopants have migrated across the PN junctions.

The higher the level of integration (more parts per square micron) the faster they'll go bad. Same is true of a lot of SF standbys such as "molecular circuitry". I wouldn't bet on *any* nano-scale tech surviving.

Damage from cosmic rays and the like are another factor.