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NEWSCIENCENEWSCIENCENEWSCIENCE Using 1/2 mv’, we get 1/2 x 9.109E-31 x 10,000 x 10,000 = 4.55E-23 joules (m = mass; v = velocity; E = exponent base 10). The work done by the electron in escaping the outer surface is 0.15 eV x 1.602E-19 = 2.4E-20 joules. So, dividing 2.4E-20 by 4.55E-23 gives 527x. This simply means that the energy used to get the replace- ment electron up to speed is 527 times less than the work it can do to generate electricity. QED! This is proof of a viable device. Note that, before, spinning the disc merely caused it to get hotter; but now, with a homopolar motor coupled to an AC generator connected to an external load, the disc gets cooler. If the disc receives no heat, it will eventually become so cold that thermionic emissions will cease. There needs to be a flow of heat from the outside world to the ring. This is achieved simply by radiative transfer. At 300 K, a black body emits 457 W/m’. A disc at 250 K (as a result of cooling) emits 220 W/m’, so it is possible to transfer 237 W/m’. If the device were in a 600 K (327°C) isothermal bath, the heat transfer to the rotor would be 8 kW/m?. electrical output. It must be so, for otherwise energy would be destroyed—and energy cannot be destroyed. This is simple arithmetic, backed by known physics, and cannot be ignored. The way ahead We need metallurgists, engineers and physicists to collaborate urgently to make this Thermionic Revolution happen. Apart from vacuum manifolds, other electron returns need to be assessed, e.g., secondary emitters. Rotating Thermionic Generators have no exhaust, so their efficiency is not Carnot constrained. Domestic power generation is possible at kilowatt scale. Megawatt generators and car power plants are possible using heat pumps driven by the RTG. Overcoming the metal problem No metal can handle a 10,000m/s tip speed, but if the outer rim is machined with an array of points with a 10:1 aspect ratio (height to base), the work function reduction increases by 1,000x (proved physics). Electrons centrifuged towards the tips of the needles become so crowded that their mutual repulsion tends to overcome the work function at the tips. By this method, the disc speed needed is 316 m/s, as a 5-meV reduction looks like a 5-eV reduction. The 0.15 eV of work done per emitted electron is 100% converted to Understanding the work function From table 1, we see that 0.15 eV can power a house. If a disc of stain- less steel spins at 100 m/s (peripheral or tip speed), then we reduce the work function by only 0.5 meV (mil- lielectronvolt). At 316 m/s, it is 5 meV. So if the metal's work function is 5 eV and the disc spins at 316 m/s, then the effective work function is 4.995 eV. At 10,000 m/s, the effec- tive work function would be almost zero, but no metal can take that strain. A different approach is required for a practical device. But first, I want to exhaust the theoretical argument about the second law. At 10,000 m/s, the effective work function is reduced to 0.15 eV. At 0.15 eV and at 300 K, large numbers of electrons escape into vacuum. They do 0.15 eV of work to get there; they are mostly exhausted. The work they did to get to vacuum is now available as an emf in the disc, to draw electrons past the magnetic intersection and thus convert current x emf into torque (driving the AC generator). But, as said before, the electron at the outside is going faster than on the inside; so we need to deduct, from the 0.15 eV work done, the energy needed to get a replacement electron up to 10,000 m/s. About the Author: Philip Hardcastle, geophysicist and electrical engineer, has created numerous technologies and has a passion for physics and invention. To contact him, visit http://www. thermionicrevolution.com. a KH ‘ ZZYZz Cif 7 Y Vv 7 Zi to Figure 3 NEXUS ¢ 51 AUGUST — SEPTEMBER 2008 www.nexusmagazine.com