ELECTROSTATICS
NEWSLETTER
September/October 2001 No.158
PRESIDENT’S MESSAGE
It seems that newsletter columns everywhere this
month begin with a commentary on the events of September 11. This newsletter will be no exception. I am sure I speak for the ESA Executive Council,
board, and the entire ESA membership in expressing our sadness at this turn of
events in American history. Regardless
of one's political affiliation (something we rarely discuss at ESA meetings) or
one's nationality (something we almost never think about within the ESA), it's
comforting to know that we can all come together in mourning for the senseless
loss of life and the end of America's long period of shelter from conflict on
its home soil.
As scientists and engineers, we sometimes we like to
relegate current events to something that goes on in the newspapers and on TV but
rarely touches our special world of scientific pursuit. The aftermath of
September 11 shows us that this is not the case. I note with dismay the canceling of numerous technical meetings
and conferences scheduled for late September and early October. These
disruptions do not make the mainstream press but nevertheless effect us in
subtle and measurable ways. The events of this month may change the way we do
business, but we must continue to do the business at hand. In that spirit, I encourage everyone to hold
on to your plans to attend the June 2002 Annual ESA Meeting. This event will be
a joint conference between the ESA and our Japanese sister society, the IEJ.
Mark the dates (June 26 - 28 at Northwestern University in Evanston Illinois,
near Chicago) firmly on your calendars. Forever the optimist, I anticipate that
the state of travel next summer will offer smooth sailing for all attendees,
including our Japanese colleagues. Help
us make this conference one of the best attended ever!
Also note that we are in the negotiation and
planning stages for the first-ever joint meeting between the ESA and the
Electrostatic Processes Committee of the IEEE Industry Applications Society
(IAS/EPC). While the memberships of the ESA and the IAS/EPC overlap substantially
(I estimate about 30%), a joint meeting has, in my view, been long overdue.
Discussions over a joint meeting have been going on quietly behind the scenes
for some time now, and the suggested plan from the ESA side is to hold one
sometime in June 2003. The location is still to be determined. Please join me
in working with our IEEE colleagues to make this conference a milestone
experience.
On a lighter note....
Last summer, I saw an ad on TV that was run by
either the electric company, the gas company, or a local public interest group
- I can't remember which. The ad
encouraged viewers to save energy in whatever way possible so as to reduce
total demand and avoid future energy shortages. To make the point about what
life would be like without enough energy to go around, the announcer suggested
that a family might instead be required to supply it's energy needs by
generating its own static electricity.
The ad flipped to a view of a father, son, and daughter rubbing their
feet like mad on a carpet and discharging their fingers to a door knob as the
mother in the shower yelled, "Faster! The water's getting
cold!". A dog sliding across a
kitchen floor into a collection plate was kept busy while his "static
electricity" was used to power lights as the family read in the living
room. Later, the father stroked the cat
while mother used the energy to cook dinner.
The ad obviously had elements of tongue-in-cheek,
but I thought it would be interesting to calculate just how much
static-producing activity might be required to power the energy needs of the
family home. Please follow me along in
my logic. As a basis for the calculation, let's use the simple human body model
from ESD studies wherein the human body is assumed to have a capacitance to
ground of about 200 pF (give or take 50 pF or so.) Let's further assume that the average charging event raises the
body potential to about 15 kV. (The ESD experts among us will have to forgive
my rough numbers.) Let's next assume,
optimistically, that the energy content of every spark can be transferred to
heating up the water. In reality, only a small fraction of the energy would be
transferable, but what the heck.
The recommended hot water temperature for human
hygienic bathing is 120oF, or about 50oC. Let's assume that the water begins at room
temperature (about 20oC,) so that its temperature must be raised by
30oC. It takes 1 calorie of
energy to raise 1 cm3 of water one degree Celsius, and 1 calorie =
4.18 joules. These various assumptions lead to the following result:
w The
energy content of a single body charging event, calculated from CV2/2,
will be 23 mJ.
w It
will require (4.18 J/ oC)(30oC) l 125 Joules to heat a cubic
centimeter of water to bathing
temperature.
w At
23 mJ per spark, it will require (125 J)/(0.023 J/spark) = 5,400 sparks to heat
the water.
w At
1 second per spark (a person really rubbing away like mad at the floor mat), it
will take 5,400 seconds, or 90 minutes, or about 1.5 hours to
heat up the water.
w At
the end of this time, the foot-rubbing spark maker will have worked up such a
sweat that he/she will need a shower more than the intended
recipient of the hot water.
w The
shower had better be a short one, however, because the above calculation
applies to just one cm3 of
water.
w Heating
up 4 liters of water (the approximate amount of water in a "Sun
Shower", a solar heated plastic bag made for taking showers on boats) will
require four thousand times as much sparking, because 1 liter =
1000 cm3. Hence the water will be ready for use in a scant
362,000 minutes, or 6,040 hours, or about 100 days.
w In
the amount of time required to heat the water, it will probably evaporate.
w It
may be time to invest in a solar water heater.
For the Friendly Society,
Mark Horenstein
ELECTRICAL DRYING
I recently heard of a process (already available in
Europe) for drying out basements with the use of electric charges. Apparently, there is a n electrical movement
of water molecules to the outside of the wall.
The power usage begins at about 60 watts and dwindles to near zero as
the house dries. Anyone tried
this? I saw a reference to Popular
Science, May 2001, but have not seen the article.
Glenn Schmieg
TESLA
Anne S. Benninghoff provided us with an interesting
news clip which appeared in an Ann Arbor newspaper. It states that Nikola Tesla was born on June 10, 1856 in Smiljan
near Gospic, Croatia. He came to the US
in 1884 arriving with just 4 cents in his pocket and a book of poems he’d
authored. He died on January 7, 1943 in
New York in a modest New York hotel room where he had spent his last lonely
years in “narrow circumstances”.
His ashes are kept in an urn in the Nikola Tesla
Museum in Belgrade, together with various personal documents, his Colorado
diary, his library and those of his instruments which have been preserved. His house in Smiljajan has been turned into
a museum.
Tesla is know to have said, “I am proud of my
Croatian homeland and of my Serbian origin.”
WHERE ESA LIVES
At last count, ESA had 218 members in 34 US states,
11 members in three Canadian provinces, and 53 members in 23 other countries.