Fast-moving particles or atoms leave tracks in many materials. Geologists assess the ages of specimens by studying the tracks of particles or recoil nuclei; microscopists use molecules or ions like light, firing them at surfaces or through samples to gain information. Technologists can make many films: polyalkane, polyester, polyamide, their laminates, and so on. DREADCO physical chemists are now firing atoms, molecules and ions through thin films from one side only. Most of the resulting damage-tracks will just be fine holes. But Daedalus reckons that, every so often, a molecular group will be pushed away but not detached. Even if it returns to its place it will easily give way again, in that same direction. He is looking for a molecular one-way valve, the equivalent of the rectifier in electronics.
Initial progress must depend on luck. Daedalus cannot guess what molecule or ion, fired at what energy at what film, will give the best one-way valve for what gas molecules. But the resulting DREADCO 'Vacfilm' will have many uses, especially for the molecules in air. Seal something inside it; if its pumping direction is outwards, it will slowly extract all internal air. The Maxwell–Boltzmann distribution gives some molecules twice the average energy or even more; these are the ones that will pass the little valves. But the process may take many weeks. Daedalus reckons that Vacfilm, like an inefficient Carnot engine, will be driven by small daily changes of temperature. Conversely, however, a mere atmosphere of adverse pressure is nothing to a molecular valve. In due course vacuum will be achieved and maintained; even small leaks will be pumped out.
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