sorry guys, perhaps I should have taken more than 30 seconds to read the article and think about my high school chemistry.
On Sep 11, 2009, at 8:27 AM, Paul Jost wrote: > Randy, > > The article specifically mentions that both electrodes are made of > the same metal. So, this is not a battery type of reaction, as in > the potato batteries with dissimilar metal electrodes. The > mechanisms are not alike. > > Paul > ----- Original Message ----- > From: Randy Brown > To: [email protected] > Sent: Thursday, September 10, 2009 8:43 PM > Subject: [ENTS] Re: tree power!!! > > Remember potato batteries? This site claims 880 millivolts. > > http://www.science-projects-resources.com/how-to-make-a-potato-battery.html > > > On Sep 10, 2009, at 4:59 PM, Paul Jost wrote: > >> A couple of hundred millivolts at microamp levels or less from a >> tree seems very reasonable. Low potential energy and charge >> storage is present in anything with unbalanced ion concentrations. >> Maybe ionic charge could be a force that helps with sap flow up the >> world's tallest trees? Only one of a kind custom semiconductors >> can run off that minute of an energy source and they spend most of >> their time trickle charging the input capacitor and then coming out >> of sleep/standby mode only briefly before shutting down again for a >> proportionately long time. It is unlikely that any real commercial >> application could be derived from this for at least several years. >> >> PJ >> >> On Thu, Sep 10, 2009 at 3:34 PM, DON BERTOLETTE <[email protected] >> > wrote: >> Steve- >> In rereading the initial post below, >> "A study last year from the Massachusetts Institute of Technology >> found that plants generate a voltage of up to 200 millivolts when >> one electrode is placed in a plant and the other in the surrounding >> soil." >> it seems that indeed, the electricity is of little magnitude, >> effective perhaps only in nano-technology and even more >> speculatively, as a measure of tree health. It's this last item >> that held my interest! >> -Don >> Subject: [ENTS] Re: tree power!!! >> Date: Thu, 10 Sep 2009 05:52:44 -0500 >> From: [email protected] >> To: [email protected]; [email protected] >> >> Pardon my skepticism here about this...trees can be conductors of >> electricity (dangers of power line contact; also lightning strike >> patterns) but I'm a little skeptical regarding the sustainable >> transmission of electricity of any magnitude. >> >> Steve Springer >> >> From: [email protected] on behalf of DON BERTOLETTE >> Sent: Wed 9/9/2009 10:49 PM >> To: [email protected] >> Subject: [ENTS] Re: tree power!!! >> >> PJ- >> I'll bet there are differences between species... >> -Don >> >> Date: Wed, 9 Sep 2009 17:02:32 -0500 >> Subject: [ENTS] tree power!!! >> From: [email protected] >> To: [email protected] >> >> ENTS, >> >> Here is a "must read" on trees from the U of Washington: >> http://uwnews.org/article.asp?articleID=51869 >> >> PJ >> >> >> University of Washington >> Electrical engineers Babak Parviz and Brian Otis and undergraduate >> student Carlton Himes (right to left) demonstrate a circuit that >> runs entirely off tree power. >> Sept. 8, 2009 | Science | Technology >> Electrical circuit runs entirely off power in trees >> Hannah Hickey [email protected] >> >> >> University of Washington >> The custom circuit is able to store up enough voltage from trees to >> run a low-power sensor. >> >> >> You've heard about flower power. What about tree power? It turns >> out that it's there, in small but measurable quantities. There's >> enough power in trees for University of Washington researchers to >> run an electronic circuit, according to results to be published in >> an upcoming issue of the Institute of Electrical and Electronics >> Engineers' Transactions on Nanotechnology. "As far as we know this >> is the first peer-reviewed paper of someone powering something >> entirely by sticking electrodes into a tree," said co-author Babak >> Parviz, a UW associate professor of electrical engineering. >> A study last year from the Massachusetts Institute of Technology >> found that plants generate a voltage of up to 200 millivolts when >> one electrode is placed in a plant and the other in the surrounding >> soil. Those researchers are working with a company, Voltree, to >> develop forest sensors that exploit this new power source. >> The UW team sought to further academic research in the field of >> tree power by building circuits to run off that energy. They >> successfully ran a custom circuit solely off tree power. >> Co-author Carlton Himes, a UW undergraduate student, spent last >> summer exploring likely sites. Hooking nails to trees and >> connecting a voltmeter, he found that bigleaf maples, common on the >> UW campus, generate a steady voltage of up to a few hundred >> millivolts. >> The UW team next built a device that could run on the available >> power. Co-author Brian Otis, a UW assistant professor of electrical >> engineering, led the development of a boost converter, a device >> that takes a low incoming voltage and stores it to produce a >> greater output. His team's custom boost converter works for input >> voltages of as little as 20 millivolts (a millivolt is one- >> thousandth of a volt), an input voltage lower than any existing >> such device. It produces an output voltage of 1.1 volts, enough to >> run low-power sensors. >> The UW circuit is built from parts measuring 130 nanometers and it >> consumes on average just 10 nanowatts of power during operation (a >> nanowatt is one billionth of a watt). >> "Normal electronics are not going to run on the types of voltages >> and currents that we get out of a tree. But the nanoscale is not >> just in size, but also in the energy and power consumption," Parviz >> said. >> "As new generations of technology come online," he added, "I think >> it's warranted to look back at what's doable or what's not doable >> in terms of a power source." >> Despite using special low-power devices, the boost converter and >> other electronics would spend most of their time in sleep mode in >> order to conserve energy, creating a complication. >> "If everything goes to sleep, the system will never wake up," Otis >> said. >> To solve this problem Otis' team built a clock that runs >> continuously on 1 nanowatt, about a thousandth the power required >> to run a wristwatch, and when turned on operates at 350 millivolts, >> about a quarter the voltage in an AA battery. The low-power clock >> produces an electrical pulse once every few seconds, allowing a >> periodic wakeup of the system. >> The tree-power phenomenon is different from the popular potato or >> lemon experiment, in which two different metals react with the food >> to create an electric potential difference that causes a current to >> flow. >> "We specifically didn't want to confuse this effect with the potato >> effect, so we used the same metal for both electrodes," Parviz said. >> Tree power is unlikely to replace solar power for most >> applications, Parviz admits. But the system could provide a low- >> cost option for powering tree sensors that might be used to detect >> environmental conditions or forest fires. The electronic output >> could also be used to gauge a tree's health. >> "It's not exactly established where these voltages come from. But >> there seems to be some signaling in trees, similar to what happens >> in the human body but with slower speed," Parviz said. "I'm >> interested in applying our results as a way of investigating what >> the tree is doing. When you go to the doctor, the first thing that >> they measure is your pulse. We don't really have something similar >> for trees." >> Other co-authors are Eric Carlson and Ryan Ricchiuti of the UW. The >> research was funded in part by the National Science Foundation. >> ### >> >> For more information, contact Parviz at 206-616-4038 or >> [email protected] >> or Otis at 206-616-5998 or [email protected]. >> >> >> >> Get back to school stuff for them and cashback for you. Try Bing now. >> >> >> >> >> >> Windows Live: Make it easier for your friends to see what you’re up >> to on Facebook. Find out more. >> >> >> >> >> > > > > > --~--~---------~--~----~------------~-------~--~----~ Eastern Native Tree Society http://www.nativetreesociety.org Send email to [email protected] Visit this group at http://groups.google.com/group/entstrees?hl=en To unsubscribe send email to [email protected] -~----------~----~----~----~------~----~------~--~---
