Realisable fusion power

I commented on this fusion-fission hydrid reactor design on Futurismic a while ago.

Researchers at the university of Texas are developing a means to process spent nuclear fuel using fusion:

The scientists propose destroying the waste using a fusion-fission hybrid reactor, the centerpiece of which is a high power Compact Fusion Neutron Source (CFNS) made possible by a crucial invention.

The CFNS would provide abundant neutrons through fusion to a surrounding fission blanket that uses transuranic waste as nuclear fuel. The fusion-produced neutrons augment the fission reaction, imparting efficiency and stability to the waste incineration process.

The reason this is exciting is that it raises the possibility of a way of developing fusion technologies incrementally and economically. Instead of going all-out to build a nuclear fusion reactor in one step, putative nuclear fusion companies could market their wares as a means of processing the nasty transuranic waste output of conventional fission reactors.

This would provide fusion companies with a source of revenue to develop more advanced magnetic containment methods, and many of the other technical requirements of fusion electricity production.

The problem with fusion technology in the form of the ITER project is it's a massive, expensive, centralised, all-or-nothing endeavour.

I entirely support ITER: but it I'd love to see some this fission-fusion hybrid fuel cycle implemented in practice.

Charles Stross makes this point about incremental development but concerning the LiftPort group, a consortium that have made the mistake (as Stross sees it) of focusing on the development of an elevator system under the assumption that the revenue-generating fullerene cable technology would appear from somewhere else.

May Almighty illuminate our intellect and inspire us towards the righteous graph...

At the moment I'm reading The Origin of Wealth by Eric D. Beinhocker because Amazon kept bugging me with it every time I bought Taleb.

And those Amazon algorithms know their stuff: Beinhocker is like Taleb only more polite, less bombastic, and generally more interesting.

TOoW leaves out most of the epistemological stuff and concentrates on wealth. So far Beinhocker has gone over why neoclassical economics is nonsense (it treats the economy as a closed, non-dynamic system, which it isn't, and treats people as perfectly rational, which they aren't).

Beinhocker is working his way towards describing complex adaptive systems of the Murray Gell-Mann variety...

In the meantime he also writes about non-linear equations and deterministic chaos: like this equation here:

B_t+1 = r * B_t * ( 1 + B_t)

Where B is the value of something at time t, and r is some other number.

When r is set to 1:


Now if you set r to 2:




Now if you set r to 3.3:


Now if you set r to 4:


Which is, apparently, chaotic.

I had always thought that in mathematical terms chaos meant "randomness", but in fact the two are very separate ideas.

A system is chaotic if it:

1. Is sensitive to initial conditions,
2. Is topologically mixed, and
3. Has dense periodic orbits.

Now I understand the first of those points, but not the second or third.

More reading to do methinks...

Comment on "The Sleepwalkers" by Arthur Koestler

The Sleepwalkers by Arthur Koestler, is a history of the study of the cosmos, starting with the ancient Babylonians and ending with a discussion of Newton, via Aristotle, Plato, Copernicus, Kepler, Galileo.

Koestler seeks to demolish the assumption that the history of this particular subset of science is a Whiggish story of Progress towards a Theory of Everything. Rather it is a story of various people blundering around and gradually and haphazardly building a picture of the universe.

These philosophers and scientists "sleepwalk" towards understanding.

Enjoyable and iconoclastic, well written but with some flaws.

Some spiritualist stuff, which comes off sounding a little odd against the otherwise respectably skeptical tone.

Claims that electromagnetism and gravity are "verbal fetishes ... disguising the fact that they are metaphysical concepts dressed in the mathematical language of physics."

Well that's an interesting perspective. I wish I knew if Koestler was speaking from a view of ignorance or understanding as regards the mathematical underpinnings of gravitational theory.

It is unfair to say gravity is a metaphysical construct. It is a theory that currently suits all available evidence very well. We believe in it because the evidence suggests it exists.

However Koestler is right to reinforce how peculiar the idea of "action at a distance" (spooky or otherwise) really is. Descartes was having none of it. Newton presented his theory of gravity but said:

"gravity must be caused by an agent acting constantly according to certain laws; but whether this agent be material or immaterial, I have left to the consideration of my readers"

Dismissive of Einstein (p 504, Chapter 3 The Newtonian Synthesis 1. 'Tis all in Pieces):

"Einstein's correction to Newton's formula of gravity is so small that for the time being it only concerns the specialist. The two most important branches of modern physics , relativity and quantum mechanics, have not so far been integrated into a new universal synthesis; and the cosmological implications of Einstein's theory are still fluid and controversial."

I think Koestler rather misses the point here: as I understand it Newton was wrong to assume space is "flat" and Einstein demonstrates that space is not flat. Newton's theories are a good approximation of what goes on in the universe, and for most purposes do well enough, but Einstein is closer to being correct than Newton.

The book was published in 1959: I think Einstein's theories were bedded down by then.

All in all, an excellent read, drawing on the original sources.

And You're Only Just Realising This?

There comes a point in every man's life when he realises that he is almost certainly never going to create one of the fundamental circuit elements of electronics.

Also: one of the things that struck me as odd about the recent discovery/invention was how old-fashioned a discovery it seems.

We are no longer used to "fundamental" breakthroughs in areas other than the biological sciences, as Charles Stross comments in this interview:

"We seem these days to be seeing new ground-breaking theoretical developments at a rate of one every six months to a year: breakthroughs on the same order as general relativity or quantum theory. (You don't see such breakthroughs routinely in physics, which is a relatively mature field, but if you look into the biological sciences equivalent breakthroughs appear to be coming thick and fast.)"

There is something wonderfully retro-1950s-buttoned-down-white-labcoat-brylcreme- and-horn-rimmed-glasses about the invention/discovery of the "memristor."

Sadly my knowledge of electronics is ever-so-slightly too limited to truly grasp the theoretical implications of this. However the practical implications look extremely interesting:

"Today, most PCs use dynamic random access memory (DRAM) which loses data when the power is turned off.
But a computer built with memristors could allow PCs that start up instantly, laptops that retain sessions after the battery dies, or mobile phones that can last for weeks without needing a charge."

I spend at least ten minutes every morning waiting for my PC to power up at work (yes I know I could agitate for a better PC... but [deleted due to imminent curtailment of career prospects - free speech go hang]).

Imagine all the time you've spent waiting for a PC to power up: adding up all those two to three minute gaps could make a lot of difference in the world. You probably wouldn't even notice power cuts.

Of course my reading of this is that "instantly" means within a second or two and that the computer would retain the current session.

Anyway there's another thing off my list of things to do before I die...

C'est la vie.

Aeroplane Conveyor-Belt Problem

I have come to the conclusion that the aeroplane will take off in the aeroplane conveyor-belt problem.

The forces acting on the plane are thrust from the engines.

The conveyor-belt will simply make the wheels spin much faster than they usually do.

The purpose of the wheels on aeroplanes is to reduce the frictional effects that act in the opposite direction to the thrust from the engines.

These frictional forces will not be greater by virtue of the wheels resting on a surface moving backwards relative to the aeroplane.

*Is the British usage "conveyer" or "conveyor" ... ? I wouldn't mind except I'm very obviously using B.E. in "aeroplane" and I'd like things to be consistent.