Power lines not dangerous...

CDale cdale@techmonkeys.net
Tue, 28 Aug 2001 23:51:21 -0500 (CDT)


The resonance of a chicken's head is 17hz.

On Tue, 28 Aug 2001, Chuck Murcko wrote:

> Hmmm. I wonder *who* will spin this one, the power companies or those
> other guys.
>
> If you're a believer, you're likely in more danger from your electric
> razor, hair dryer, or running your laptop on the AC adapter than from
> living near a 500 KV power line, aesthetics aside.
>
> Note that square law doesn't apply here, the near field effects swamp
> the far field effects at 5000m wavelengths.
>
> http://www.calpoly.edu/~dhafemei/background2.html
>
> Excerpt:
>
> "A typical U.S. home has the Earth's  constant magnetic field of about
> 450
> mG and a 60-Hz background magnetic field level (primarily not from power
> lines) that ranges from 0.5 mG to 4 mG with an average value of 0.9 mG.
> Five percent of the homes have fields above 2.9 mG, and 1% are above 6.6
> mG.  For comparison sake, one study reports that electrical powerline
> workers experience an average field of 11 mG.  Typical transmission power
> lines produce average fields at distances of 30 and 60 meters as follows:
>
> 				E (V/m at 30/60 m)	B (mG at 30/60 m)
> 115 kV			0.07/0.01			1.7/0.4
> 230 kV			0.3/0.05			7.1/1.8
> 500 kV			1.0/0.3			12.6/3.2
>
> As a simple example, a two wire 500 MW transmission line at 500 kV draws
> 500 amperes in opposing directions in the two wires.  From Ampere's law a
> single wire of 500 A produces a field of 33 mG at a distance of 30 m.  If
> two opposing currents of 500 A are separated by 4 meters, the field will
> be 4.4 mG (in the plane of the wires).  By reducing the separation to 1
> m, the field falls to 1.1 mG.  At a doubled distance of 60 m, the field
> from the single conductor is 17 mG and the fields from the paired
> conductors are 1.1 mG for a 4-meter separation and 0.3 mG for 1-meter
> separation.  Motor and appliance electrical coils produce either magnetic
> dipole or quadrupole fields that diminish as the inverse square or cube
> of the distance, respectively.  Average fields at a distance of 30 cm
> are: color television (7 mG), microwave (4 mG), analog clocks (15 mG),
> electric razors (20 mG, 100 mG at 15 cm) and hair driers (1 mG, 300 mG at
> 15 cm). "
>
> I wonder just what the field strength was in these tests? It must have
> been pretty high compared to standing under an HV transmission line,
> unless they just dropped cables into the water and used that as the
> current carrying medium. Of course that approach resembles electrocution
> more than radio.
>
> Didn't we go through this twenty years ago with the Video Display
> Terminal (VDT) scare?
>
> Chuck
>
> On Tuesday, August 28, 2001, at 10:09 PM, Adam L. Beberg wrote:
>
> > "Zebra mussels in an aquarium that were exposed to very low-frequency
> > electromagnetic waves - around 60 hertz, or similar to what is emitted
> > by a
> > power outlet - died within 40 days"
> >
> > So does this classification of 60hz EMF as a large scale biological
> > weapon
> > hurt the power companies claim that's it's harmless?
> >
> > Wonder how they will spin this one :)
> >
> > - Adam L. "Duncan" Beberg
> >   http://www.iit.edu/~beberg/
> >   beberg@mithral.com
> >
> >
> > Study: Radio Waves May Kill Mussels
> >
> > By TAMMY WEBBER, Associated Press Writer
> >
> > CHICAGO (AP) - Low-frequency radio waves might someday be used instead
> > of
> > chemicals to control zebra mussels, which cause millions of dollars in
> > damage by clogging water intake pipes at power plants and other
> > installations, researchers said Tuesday.
> >
> > Zebra mussels in an aquarium that were exposed to very low-frequency
> > electromagnetic waves - around 60 hertz, or similar to what is emitted
> > by a
> > power outlet - died within 40 days, according to a study conducted by
> > undergraduate students at Purdue University-Calumet in Hammond, Ind.,
> > and
> > presented Tuesday at an American Chemical Society meeting in Chicago.
> >
> > Though field trials still must be conducted, the technology appears
> > promising, said Matthew F. Ryan, associate professor of chemistry at
> > Purdue.
> > The technique appears to be safe for fish and other aquatic life, he
> > said.
> >
> > Chemicals such as chlorine and bromine have been used to kill the
> > mussels,
> > but there are concerns about the safety of the substances, Ryan said.
> >
> > Brought to the United States in the ballast water of oceangoing ships
> > in the
> > 1980s, zebra mussels spread rapidly through the Great Lakes and other
> > inland
> > waterways and have caused millions in damage to power plants and boats.
> >
> > Gary Wege, a biologist with the U.S. Fish and Wildlife Service in
> > Minnesota,
> > welcomed the study, saying that most efforts to control zebra mussels
> > have
> > failed.
> >
> > ``If you could zap the critters right from the water, that would be
> > great,''
> > Wege said.
> >
> > If the technique proves effective, Wege said, electrical barriers could
> > block the mussels from infesting other waters.
> >
> > Ryan said irradiation appeared to cause zebra mussels to lose large
> > amounts
> > of calcium - essential for shell health and muscle control - as well as
> > sodium and potassium. Only 10 percent of unexposed mussels in another
> > tank
> > died after 40 days, he said.
> >
> > During experiments, fish collected from the same waters and put in the
> > same
> > tank as the mussels survived. Native clams did not die until being
> > exposed
> > for 90 days.
> >
> > Ryan said the technology would have to be installed in intake pipes and
> > the
> > radio waves aimed at specific spots.
> >
> >
> >
> > http://xent.com/mailman/listinfo/fork
> >
>
> Chuck Murcko
> Topsail Group
> http://www.topsail.org/
>
>
> http://xent.com/mailman/listinfo/fork
>

-- 
"My theology, briefly, is that the universe was dictated but not
          signed."  (Christopher Morley)