gh RADIO WAVES CLEAN THE ROOF

The developers took care not only of street cleaners, who have to climb the roofs and clean them from ice and snow by scrapers and shovels, but of pedestrians who icicles and layers of ice threaten to.

The system operation is based on the phenomenon discovered by Igor Levin, Ph.D. (Engineering Sciences), research manager of the development. Its physical essence is rather complicated and is not fully found out, but its outer side is rather visual. Moreover, any passer-by can observe it if he/she turns out to be at 11 p.m. sharp in winter in the vicinity of stations of newly constructed monorail railway near the Exhibition of National Economy Achievements in Moscow.

So, at 11 p.m. sharp, above the station roof, as if my miracle fountains of snow and small pieces of ice begin to fly up, as if shot, the pieces flying up rather high - about three meters up. The sight is fabulous, but is does not last long - for several minutes. Along with that, both compacted snow and ice crust immediately turn into flour which slips down from the roof absolutely safely for the passers-by and is spread by wind.

"It is surprising that this has not been shot by TV-men so far, as this is close to the TV centre in Ostankino," says Igor Levin. He adds, "Our system operates as follows: we have placed a network of small devices directly under the roof, the devices emitting a short, one-millionth of a second, but very powerful radio-frequency pulse. Hashing of impulses of several generators working synchronously results in emergence of strong electromagnetic field, which is converted at the roof/snow boundary into powerful acceleration field. It tears the snow/ice crust off with great force, breaking it and throwing it up transversely to the impulse direction. Snow and ice as if explode and roll down. And the roof remains absolutely clean. This is done automatically, computer at the station controlling the system operation."

However, the question arises whether these electromagnetic pulses are dangerous to underground equipment, radio communication or people? The authors claim that there is no danger. Firstly, the pulses are extremely short. Secondly, the device operated at the frequency of about 1 kHz, while the cellular communications wave-length is by ten times less - the MHz frequency range is typical for it. Finally, the devices were specially tested and it turned out that they were quite harmless.

The authors are now developing a similar system for small airplanes antiicing. In that case similar sensors will remove ice from wings, if it freezes on. Recently, a system based on the same principle was produced for a milk plant! They clean not roofs but tanks where dried milk is manufactured via dispersing and immediate drying up of ordinary liquid milk. The cauldrons resembling huge pots have to be regularly cleaned from dried milk layer stuck inside. Previously, this was done manually, now - with the help of electromagnetic pulses. It's a pity the authors have not invented such systems for domestic use yet. Otherwise, there would be no need to scrub pots and frying pans.

***