Wednesday, January 17, 2007

» A Taste of Nikola Tesla

Nikola Tesla was perhaps the greatest scientist of the 20th century. Though Albert Einstein’s discoveries get more credit, Tesla’s work made a more significant difference in our everyday lives.
He invented radio (before Guglielmo Marconi), alternating current (which allowed the electric grid), the transistor and hundreds of other things. One of his claims was to have discovered a way to transmit power wirelessly over vast distances. (I know a European physicist who believes he has figured out how this works.)
Now comes a practical application of this through the phenomenon of resonance. Resonance causes an object to vibrate when energy of a certain frequency is applied. Resonance happens when, for example, a tuning fork is struck and other tuning forks also begin to vibrate, or when an opera singer hits a certain note and glass shatters.
According to assistant professor Marin Soljacic of the Massachusetts Institute of Technology, one of the researchers behind the work, the complex weaving of cables and plugs needed to recharge today’s electronic gadgets could soon be a thing of the past.

It’s a relatively simple system, one that could power devices such as laptop computers, cell phones and MP3 players.
It uses well-established physics and could work over large apartments, houses or even greater distances.
While the researchers have not built a working model, their computer models and mathematics suggest it will work. Such models have proven so accurate in recent years that they often substitute for physical experiments.
The challenge in electromagnetic resonance is the tendency of systems to radiate; they scatter energy in all directions, wasting large amounts of it. Consequently, the team focused on a special class of “nonradiative” objects with so-called “long-lived resonances.”
Said professor Soljacic, “If you bring another resonant object with the same frequency close enough, the energy can tunnel from one object to another.”
For instance, a copper antenna designed to have proper resonance could transfer energy to a laptop with its own antenna resonating at the same frequency. The computer would truly be wireless.
One important feature of the new approach is that any energy not transferred to an appliance is simply reabsorbed.
Another is that, as professor Soljacic points out, “You could also scale it down to the microscopic or nanoscopic world,” thereby potentially providing a solution to the question of delivering power to systems, which may themselves be smaller than available wires.
Other approaches to wireless transfer of power have been proposed, including lasers. However, this is the first that appears practical without requiring line-of-sight access.
Potentially, this will change how everyone uses mobile appliances. Beyond computers, cell phones and the like, the technology could work with devices such as flashlights and anything else that is frequently moved from one spot to another.
However, there are some interesting difficulties the researchers have yet to address. For instance, one issue with wireless Internet is the stealing of bandwidth by those who have not paid for it.
The same challenge would likely appear with wireless transfer of power, except with greater significance because of the greater cost and the likelihood that a drain on power would prevent a device from working at all.
Still, within a closed space such as a home or office, this would appear to be a superior solution. On a broader scale, while it might not be possible to place such systems in open places such as airports, I could foresee charging stations being built and offering metered power for all manner of appliances without the need for special adapters.
They would need a way to shield the electromagnetic radiation, but that’s not difficult. For example, a Faraday cage — essentially, a copper wire mesh — should do the trick.
To your profitable future,
Jonathan Kolberfor The Daily Reckoning Australia

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