Material Turns Sound Waves Into Electricity
Written by Yoni Levinson
Just when you thought that engineers have run out of ideas for harvesting power from mundane human activity, a scientist from Texas A&M invents a piezoelectric material that can turn sound waves into electricity. His idea? Stick it in a cell phone.
Piezoelectric materials generate an electric voltage when subjected to some sort of mechanical stress. When you read about harvesting energy from footsteps or dancing, for example, piezoelectrics are involved. What’s novel about this application is that it exploits nanoscale piezoelectric properties. When such a material is precisely between 20 and 23 nanometers thick, it can capture 100% more energy.
Such a size makes this material perfect to stick into a cell phone. The sound waves emitted by the phone (as well as, presumably, those emitted by its owner) exert stress on the material, which in turn generates electricity. Obviously, energy can’t be generated from nowhere. But if it can simply be absorbed from the environment, you could have – for all intents and purposes – a self-charging device.
As preposterous as it may sound (especially since I still don't have my jet pack, nor my flying car) there is a movement to create a "space elevator" which could eliminate short term rocket travel and facilitate a constant gateway into earth's orbit. Here's the basics at Wikipedia: http://en.wikipedia.org/wiki/Space_elevator . It would essentially be a cable connected to a counter-weight in geosynchronous orbit creating a sort of dumb-waiter system. Hopefully this video from www.spaceelevator.com will help explain further...
LONDON, England (CNN) -- A new space race is officially under way, and this one should have the sci-fi geeks salivating.
The project is a "space elevator," and some experts now believe that the concept is well within the bounds of possibility -- maybe even within our lifetimes.
A conference discussing developments in space elevator concepts is being held in Japan in November, and hundreds of engineers and scientists from Asia, Europe and the Americas are working to design the only lift that will take you directly to the one hundred-thousandth floor.
Despite these developments, you could be excused for thinking it all sounds a little far-fetched.
Indeed, if successfully built, the space elevator would be an unprecedented feat of human engineering.
A cable anchored to the Earth's surface, reaching tens of thousands of kilometers into space, balanced with a counterweight attached at the other end is the basic design for the elevator.
It is thought that inertia -- the physics theory stating that matter retains its velocity along a straight line so long as it is not acted upon by an external force -- will cause the cable to stay stretched taut, allowing the elevator to sit in geostationary orbit.
The cable would extend into the sky, eventually reaching a satellite docking station orbiting in space.
Engineers hope the elevator will transport people and objects into space, and there have even been suggestions that it could be used to dispose of nuclear waste. Another proposed idea is to use the elevator to place solar panels in space to provide power for homes on Earth.
If it sounds like the stuff of fiction, maybe that's because it once was.
In 1979, Arthur C. Clarke's novel "The Fountains of Paradise" brought the idea of a space elevator to a mass audience. Charles Sheffield's "The Web Between the Worlds" also featured the building of a space elevator.
But, jump out of the storybooks and fast-forward nearly three decades, and Japanese scientists at the Japan Space Elevator Association are working seriously on the space-elevator project.
Association spokesman Akira Tsuchida said his organization was working with U.S.-based Spaceward Foundation and a European organization based in Luxembourg to develop an elevator design.
The Liftport Group in the U.S. is also working on developing a design, and in total it's believed that more than 300 scientists and engineers are engaged in such work around the globe.
NASA is holding a $4 million Space Elevator Challenge to encourage designs for a successful space elevator.
Tsuchida said the technology driving the race to build the first space elevator is the quickly developing material carbon nanotube. It is lightweight and has a tensile strength 180 times stronger than that of a steel cable. Currently, it is the only material with the potential to be strong enough to use to manufacture elevator cable, according to Tsuchida.
"At present we have a tether which is made of carbon nanotube, and has one-third or one-quarter of the strength required to make a space elevator. We expect that we will have strong enough cable in the 2020s or 2030s," Tsuchida said.
He said the most likely method of powering the elevator would be through the carbon nanotube cable.
So, what are the major logistical issues keeping the space elevator from being anything more than a dream at present?
Massachusetts Institute of Technology aeronautics and astronautics Professor Jeff Hoffman said that designing the carbon nanotube appeared to be the biggest obstacle.
"We are now on the verge of having material that has the strength to span the 30,000 km ... but we don't have the ability to make long cable out of the carbon nanotubes at the moment." he said. "Although I'm confident that within a reasonable amount of time we will be able to do this."
Tsuchida said that one of the biggest challenges will be acquiring funding to move the projects forward. At present, there is no financial backing for the space elevator project, and all of the Japanese group's 100-plus members maintain other jobs to earn a living.
"Because we don't have a material which has enough strength to construct space elevator yet, it is difficult to change people's mind so they believe that it can be real," he said.
Hoffman feels that international dialogue needs to be encouaraged on the issue. He said a number of legal considerations also would have to be taken into account.
"This is not something one nation or one company can do. There needs to be a worldwide approach," he said.
Other difficulties for space-elevator projects include how to build the base for the elevator, how to design it and where to set up the operation.
Tsuchida said some possible locations for an elevator include the South China Sea, western Australia and the Galapagos Islands in the Pacific Ocean. He said all of those locations usually avoided typhoons, which could pose a threat to the safety of an elevator.
"As the base of space elevator will be located on geosynchronous orbit, [the] space elevator ground station should be located near the equator," he said.
Although the Japanese association has set a time frame of the 2030s to get a space elevator under construction -- and developments are moving quickly -- Hoffman acknowledges that it could be a little further away than that.
"I don't know if it's going to be in our lifetime or if it's 100 or 200 years away, but it's near enough that we can contemplate how it will work."
Building a space elevator is a matter of when, not if, said Hoffman, who believes that it will herald a major new period in human history.
"It will be revolutionary for human technology, and not just for space travel. That's why so many people are pursuing it," he said. "This is what it will take to turn humans into a space-bearing species."
In light of the video above and with Gustav heading towards the Coast, I thought it would be good to get some information up about hurricanes in general as well as some text from articles that can give a better idea of how this phenomena changes throughout its life cycle.
Here's a great explanation and some links from Seth Borenstein, AP Science Writer
Gustav headed for current that fuels big storms
WASHINGTON - The difference between a monster and a wimp for Gulf of Mexico hurricanes often comes down to a small patch of warm deep water that's easy to miss. It's called the Loop Current, and hurricane trackers say Gustav is headed right for it, reminiscent of Katrina.
Gustav is likely to reach this current late Saturday, experts say. What happens next will be crucial, maybe deadly.
If Gustav hits the Loop Current and lingers in that hot spot, watch out. If the storm misses it or zips through the current, then Gustav probably won't be much of a name to remember.
The meandering Loop Current, located in the southeastern gulf, provides loads of hurricane fuel. It was a key stopover for nearly all the Gulf Coast killers of the past, including Katrina and Camille, said Florida International University professor Hugh Willoughby, former director of the government's hurricane research division.
Lynn "Nick" Shay, University of Miami meteorology and oceanography professor, flew over the gulf Thursday in a federal hurricane research plane to measure the Loop Current. He saw Gustav's forecast track going "right down the throat" of it.
"That's kind of the scary part here," Shay said. "You look at this and say, 'Boy I hope this thing doesn't really explode,' but it probably will."
It happened in 2005. "Katrina went over the Loop Current and intensified rapidly," said Mark DeMaria, a Colorado-based expert on hurricane strength with the National Oceanic and Atmospheric Administration.
Then less than a month later a weak tropical storm named Rita followed Katrina into the Loop Current. Thirty hours later it was a Category 5 monster.
Both Katrina and Rita later weakened — which often happens_ to Category 3 storms by landfall.
In the last several years, meteorologists have focused more attention on the Loop Current, which is only a couple of hundred miles long and not even 100 miles wide. The evidence linking it to the worst storms is beyond circumstantial, Shay said.
What's crucial is the depth of warm water in the current — several hundred feet — because it provides continuous high-octane fuel for a storm. Hurricanes use the heat from the water to grow stronger and in the process they churn up cooler water from below, which then slows or stops the feeding process. But in the Loop Current, the deeper water is also warm and it further feeds the storm.
The Loop Current constantly shifts, growing and shrinking and sending out smaller eddies. It's now starting to contract, but not soon enough.
On Friday, the National Hurricane Center warned: "Gustav is expected to be a large powerful hurricane as it approaches the northern gulf coast."
The one hopeful sign is that on his hurricane flight Thursday, Shay saw a pool of extra cool water north and west of the Loop Current. That could help counteract what he fears will be rapid strengthening.
On the Net:
An image of the current loop current by the University of Miami:
Today I could have juice for breakfast and anything vegetable so I decided to go to the Mockingbird in downtown Bay St. Louis and have a delicious Spinach salad with walnuts and a raspberry vinaigrette. Delcious!