It is a popular prophecy that members of the rising generation will carry much electronic equipment on their persons, either integrated with their clothing or embedded in their bodies. The development of power supplies for such equipment is of course legitimate subject matter for MPS, certainly on this page, but this month I feel bound to retail two pertinent reports that have appeared elsewhere. They are quite separate contributions to a single issue of EPSRC Newsline, a journal published by the UK’s Engineering and Physical Sciences Research Council.

One of the reports is about the Tempos project at Imperial College, London. There, Dr Eric Yeatman is leading work on what he describes as ‘a microgenerator that can be driven from human motion, either by being worn on the body or implanted’. Dr Yeatman has a new class of device, a ‘parametric generator’, that operates capacitively rather than inductively, and it delivers pulses of energy, efficiently, when bodily movements make it go.

The other report is about British research that is building on biological studies led by Professor Tom Eisner at Cornell University, USA. Eisner’s team discovered how the bombardier beetle produces a 100°C jet of steam and benzoquinone to repel predators. Andy McIntosh, the thermodynamics and combustion professor at Leeds University, UK, is investigating the beetle’s combustion chamber in detail. He has already found that the insect times the actions of the chamber’s inlet valve to avoid blowing itself up, and that it controls the pressure of its defensive-offensive jet. McIntosh seeks inspiration from the unique combustion process employed by the bombardier and looks forward to application of his results to the advancement of gas turbine engineering.

Viewing the two reports together I get a stereoscopic perspective of the life to come. Electronically accoutred or implanted citizens will accommodate insect-sized heat-engine-driven generators to supply their base load: body-motion-driven generators will supply the rest of the power required. Or maybe it will be the other way round. Or perhaps a bit of each.

Whatever. Our next sister journal may yet be titled IPS, or Intimate Power Systems. Don’t forget that you read about it here first.

Fickleness may be fundamental

Some constants really are. Constant, I mean. Pi, for instance: one of my dictionaries calls this old-timer absolute, which means it is always and everywhere the same. And you don’t expect trigonometrical functions (sine, cosine etc, which, like π, you can compute to as many places as you like) to vary, though you might not describe the tabulated figures as fundamental or natural constants.

I read in CERN Courier (the high energy physics journal that is the house magazine of CERN, the European Organisation for Nuclear Research) that: ‘The natural constants are to some extent abnormal features of the theories considered today. On one hand they are needed to describe the theories, but on the other hand nobody understands their rather strange values. Indeed, no-one knows if they are accidents, or whether they can be calculated from some basic principles’.

More disconcertingly, the Courier writer notes recent astrophysical observations suggesting that a particular constant (which is known as the fine structure constant and is importantly connected with the electromagnetic interaction) has grown minutely during the lifetime of our universe. Curiously, evidence from the extraordinary natural nuclear reactor at Oklo, Gabon, West Africa, indicates that the constant in question has indeed stayed constant over the last two billion years, implying that it enjoyed its slight growth only during the youth of the universe.

Apparently, a cosmological time-dependence of some fundamental ‘constants’ has been contemplated by physicists since the 1930s. The fine structure constant that is now enlivening their thoughts has among its ingredients those well established fundamental quantities. Planck’s constant, the speed of light and π. Any time-dependence of the fine structure constant is considered likely to lurk elsewhere in that number’s composition, but who could resist a fleeting fancy that even the ‘absolute’ constants wobbled once?

A physicist colleague assures me, however, that possible inconsistencies, far away on a cosmological time scale, raise no immediate threat to power system people. The values of natural constants remain, for practical purposes, firm. What a relief!