At 05:22 pm 21/08/2005 -0500, Richard wrote: > Grimer wrote..
>> Do you remember the water based vacuum pumps one used >> in chemistry class - the ones where a constrained jet >> of water passes though and sucks air out of the connected >> vacuum apparatus. > Obviously Frank has been examining his wife's perfume atomizer <grin>. Thanks for that example, Richard. That is a much better device than the one I suggested since it is the essence of simplicity from what I remember of my mother's scent spray. In the case of the old fashioned ones the two tubes are naked and their mutual geometry is obvious. I had looked up the well known Pitot tube as an alternative example but found the explanations confusing and contradictory in the sense that they seemed to adopt different datum pressures. The scent spray is excellent by comparison. What I find very interesting is that when I first encountered the cavity magnetron many years ago its working was a complete mystery to me and I could not see the significance of the cavities at all. Once one looks at it in terms of the Beta-atmosphere being a real atmosphere, just like the Alpha-atmosphere then it's like throwing the switch on a bright lamp. Things become very clear. As regards the Beta-atmosphere pressure drop, I rather jumped the gun there cos the cavities are in resonance which means that the dominant aspect is the oscillating pressure. This takes place so fast that the inertia of the magnetron walls will prevent significant deformations. If one could rectify the sine wave so as to get an RMS pressure drop then it would be a very different ball game. I suspect this is at the root of the Hutchison Effect. Unwittingly he has stumbled upon a way of doing this. A case of an uninhibited amateur rushing in where angels fear to tread. Once one realises that one is dealing with a real atmosphere then all sorts of interesting possibilities arise - like creating closed vortices - Beta-atmosphere smoke rings in other words. There is a wonderful Royal Institution demonstration of a smoke ring blowing generated at one end of the lecturers bench blowing out a candle at the other. The smoke ring box is first filled with smoke so that the ring is visible as it travels slowly the dozen or so feet towards the candle. Then the demonstration is repeated without smoke and the lectures starts a countdown. When he reaches zero the candle is blown out as though by magic. Before WWII there was a lot of interest in the possibility of a death ray knocking down enemy aircraft. The idea was researched and considered a non starter. But the investigation did give rise to something only a little less valuable, viz. radio location and radar. Had the authorities recognised the possibility of firing Beta-atmosphere closed vortices the "death ray" might have come to fruition. Who was it who made a great hoo-ha about something like this? I think it was Shoulders with his EVOs. I'll have to google it. Cheers, Frank Grimer
