Robert J. Chassell wrote: > Have new technological innovations required human generations to pass > before powerful inventions became commonplace? Put another way, do > people have to become really used to an innovation before it can be > made powerful? > > My thesis here is that since the beginning we have seen four stages > (at least, in physics dependant technology): > > Technlogies involving > > 1. whole atoms and molecules, > which you could see > > 2. electricty, > which you could feel > > 3. nuclei and nuclei-related radiations, > which you could neither see nor feel, but which you could detect > > 4. quantum mechanics, > which you could not understand, but which you could calculate > > In the 18th century in the first stage, technological innovation > involved actions with whole atoms and molecules, for example, > > * canals in which the bed and banks of stone and dirt channeled the > fluid water; > > * textile machines in which spools and spindles held fibers and > thread; and, > > * steam engines in which metal cylinders held steam. > > These early technological innovations consisted of visible matter > re-arranged. (Well, steam could not be seen; but it condensed into > water that could.) Nowadays, we speak of atoms and molecules. > > Powerful steam engines, huge textile factories, and big canals came > generations after the first steam engines, textile machines, and > canals. > > Incidentally, an internal combustion engine uses visible matter so in > that sense it is a first stage device. But the gasoline vapor in it > is exploded by a second stage technology, an electric spark (excepting > in Diesel engines). Moreover, in normal operation, parts in an engine > move too fast to see. The internal combustion engine did not come > into widespread use until after the second stage had been around for > several generations. > > The second stage involved a fluid moving through certain kinds of > solid -- an electric `fluid' moving through `conductors'. This must > have been very strange for humans accustomed to rivers, canals, and > pipes in which the contents was visibly different from the container > and in which nothing could move through a solid. > > While a weak electric `fluid' could be tasted and a strong one gave a > shock, there was no obviously visible reason why salty water conducted > and sweet water did not. Reflecting metal could be seen as different > from non-reflecting rubber, a visible difference, but both were > solids. How could anything move through a solid? > > An early and famous use of this second stage technology involved > relatively weak electric `currents' in signalling: the electric > telegraph. The electric motor was invented within the same generation > as the electric telegraph became practical but the electric motor > itself did not become powerful or widely used for a very long time. > > (Incidentally, nowadays, we speak of electrons, a crowd moving along, > but we also speak of electric `currents' and the `flow' of > electricity.) > > The third stage involved something that could not be felt or tasted > and which could move through anything. Fortunately, X-rays could be > detected from the beginning with photographic plates and with certain > salts such as zinc sulfide. The latter was good for medical X-rays > machines and for painted, radium containing, wrist watch numbers. > > Nowadays, we say that all this involves nuclei and radiations > involving nuclei. > > Although nuclear radiations were used weakly in glowing paint, nuclei > themselves were not used for power for two generations: they were > first used in the nuclear bombs that exploded over Hiroshima and > Nagasaki and then in nuclear reactors as hot water boilers for > electric power plants. > > Interestingly, the bombs involved a first stage technology, bringing > visible stuff together, but in a high tech way: quickly moving the > two uranium hemispheres together in the previously untested Hiroshima > gun-type bomb, and even more quickly, compressing the plutonium in the > Nagasaki implosion bomb. > > The `slow' power part of this third stage involved a nuclear reactor > as a `hot water boiler'. This, incidentally, is just what coal does: > it produces heat that converts water to steam in a boiler. > > Incidentally, nowadays, no one uses the nuclei of thorium, although > India, which has large deposits of thorium, is beginning a test using > uranium and plutonium to provide the neutrons. (Although not fissile > itself, a nucleus of thorium-232 will absorb a neutron to produce > uranium-233, which is fissile.) On its own, thorium cannot sustain a > nuclear reaction. However, thorium can be used in combination with a > neutron source such as a uranium and plutonium nuclear reactor. > > Even better, Carlo Rubbia, a physicist, suggested building a thorium > reactor with an electrically operated neutron source such as that > provided by a linear accelerator or a not-very-good, but currently > buildable, hydrogen-fusion device. > > Just like normal uranium and plutonium, thorium produces radioactive > products that are dangerous. However, thorium is a lower numbered > element than regular uranium or plutonium. In general, its fission > products come after the transmutation thorium-232 to uranium-233 and > the latters' fissioning. These products do not have half-lives as > long as those from higher weighted uranium or plutonium. > > Nonetheless, these fission products do last dangerously for thousands > of years. But they do last for tens of thousand of years. Moreover, > a thorium device can also be used to reduce the danger of other > high-level nuclear waste by converting long-lived radio-actinides into > shorter lived radioactive elements. > > The fourth stage involves something that not only cannot be seen, like > water, or felt, like an electric current, or detected, like X-rays or > gamma rays, and which cannot readily be understood but which can be > calculated: quantum mechanics. > > With quantum mechanics, we speak of waves that are also particles, of > the magnetic spin of an electron whose dimensions cannot be measured, > of the probability of a particle jumping over or tunneling through a > barrier that on average prevents such a leak. > > At the moment, quantum mechanics demonstrates itself in the tunnel > diodes used in communications and computers. But technologies > involving quantum mechanics are not used for large scale power > generation, whether quickly in an explosion, or slowly in a power > plant. > > > As for low-density energy sources: > > Currently, wind is the most successfully harnessed of the low-density > energy sources. Wind powered electric generators now produce > electricity ata cost not so different from oil-fired electric > generators. > > These successful wind generators mainly use first and second stage > technologies. However, they use computers for control. > > Are control computers an example of a fourth stage innovation being > necessary for the proper functioning of an earlier stage device? If > so, is this because otherwise to work economically, the device > requires a high-density source of energy -- a steady and strong wind? > > Solar voltaic cells, which use third or fourth stage technologies, are > still costly. > > > A query: > > Thermal electric generators use a third stage technology, a vacuum in > which electrons boil off a hot source and travel to a cool collector. > Yet they are hardly commonplace. > > Is it more expensive to pump the necessary vaccuum for a one gigawatt > device, the electical output of a contemporary power station, than to > build a steam turbine and electric generator? If pumping the vacuum, > and keeping it, are expensive, then we see the costs of a first stage > technology. However, does the high vacuum needed by a thermal > electric generator require a second or third stage technology of some > sort? Is this the case? > > Or is a thermal electric generator in effect a `low-density energy > source' that requires too much `boil off' surface area for economic > use? >
Hmm, I can't answer your question, but reading this did make me think and led to an enjoyable exploration of thermo-electric engines and their dark side, peltier coolers, of which I have one, sadly broken. Thanks, Andrew _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
