Letters 05-02-2016

Facts About Trails I would like to correct some misinformation provided in Kristi Kates’ article about the Shore-to-Shore Trail in your April 18 issue. The Shore-to-Shore Trail is not the longest continuous trail in the Lower Peninsula. That honor belongs to the North Country Trail (NCT), which stretches for over 400 miles in the Lower Peninsula. In fact, 100 miles of the NCT is within a 30-minute drive of Traverse City, and is maintained by the Grand Traverse Hiking Club...

North Korea Is Bluffing I eagerly read Jack Segal’s columns and attend his lectures whenever possible. However, I think his April 24th column falls into an all too common trap. He casually refers to a nuclear-armed North Korea when there is no proof whatever that North Korea has any such weapons. Sure, they have set off some underground explosions but so what? Tonga could do that. Every nuclear-armed country on Earth has carried out at least one aboveground test, just to prove they could do it if for no other reason. All we have is North Korea’s word for their supposed capabilities, which is no proof at all...

Double Dipping? In Greg Shy’s recent letter, he indicated that his Social Security benefit was being unfairly reduced simply due to the fact that he worked for the government. Somehow I think something is missing here. As I read it this law is only for those who worked for the government and are getting a pension from us generous taxpayers. Now Greg wants his pension and he also wants a full measure of Social Security benefits even though he did not pay into Social Security...

Critical Thinking Needed Our media gives ample coverage to some presidential candidates calling each other a liar and a sleaze bag. While entertaining to some, this certainly should lower one’s respect for either candidate. This race to the bottom comes as no surprise given their lack of respect for the rigors of critical thinking. The world’s esteemed scientists take great steps to preserve the integrity of their findings. Not only are their findings peer reviewed by fellow experts in their specialty, whenever possible the findings are cross-checked by independent studies...

Home · Articles · News · Features · Piezoelectricity
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Harley L. Sachs - April 12th, 2010
Piezoelectricity: Power under pressure
You probably never heard of piezoelectricity but you have used it if you have an outdoor grill with a push-button igniter. The phenomenon gets its name from the Greek word piezo which means push. Push on a ceramic crystal and you get a spark of electricity which, in the case of your grill or the gas/electric refrigerator in your camper, ignites the propane. It’s a strange phenomenon which may someday become a source of electricity by harnessing the pressure exerted on highways or railway tracks.
This phenomenon was first discovered and described by Pierre and Jacques Curie in 1880. It was then just a laboratory curiosity, but it later found application in microphones, which employ electric energy created by the pressure of sound waves on crystals.

Piezo electricity was utilized in 1917 for submarine detection in World War I. That early form of sonar sent out a chirp or ping that bounced off submerged submarines. Currently, you may have seen the piezoelectrical effect in dance halls where someone stepping on a portion of the floor lights it up.
Now there’s an Israeli company called Innowattech, affiliated with the Technion, the country’s premier engineering university, which plans to use piezoelectric pressure plates built into a highway to generate electricity.
The idea developed at the Technion is to bury piezo plates in a stretch of highway to generate electricity from the pressure as cars pass by. Utilizing the energy of a car’s tires pressing down on the highway does not affect the vehicle’s performance. Of course, to generate a continuous flow, you need a continuous flow of traffic, which can only be found during rush hour.
An alternative is to put the piezo generators under railway ties where train traffic is heavy, like the New York or London subway system, where trains are passing every few minutes and continuous pressure is applied to the rails somewhere in the system.

If you ever watched what the rails do as a freight train passes over them, you may have seen how the portion of the track under the wheels of the cars sinks and the portion between the wheels lifts. Some of that energy can be converted to electricity.
The challenge is to link those brief sparking moments so they produce a continuous flow of current. You can’t get that from your grill igniter, but imagine a whole row of them triggered sequentially. The Innowattech plan is to build piezo generators under an experimental 90-foot strip of highway outside Tel Aviv, preliminary to a later half-mile section of road. The projected production of electricity from the half mile is expected to be about 100 kw of electricity, enough to power about 40 houses.
Cost benefit calculations suggest that electricity generated under a highway would cost between 3 and 10 cents a kilowatt hour, comparable to what is generated by wind energy. Fossil fuels cost about 5 cents per kilowatt and solar about the same.
The highway piezo generators will be buried about one inch below the surface. The generators are to go under asphalt, which is flexible, unlike concrete.

That all sounds pretty good, but I wonder how long such an installation will last. Though the piezo material can last 30 years, I haven’t seen a stretch of highway in the United States that can go that long before it develops deep potholes. Maybe the Israeli roads are built better.
Putting the piezo generators under railway ties sounds like a more durable alternative.
You have to give the Israelis credit for coming up with new ideas and innovations. Israel has more Ph.Ds per 100,000 than any other country and produces more patents per 100,000 population. A highway that generates electricity is only one of them. Uri Amit, president of Innowattech, believes piezo generated electricity has a future.
There’s even a plan to light a passageway in a high traffic area in Chicago simply by the pressure of people’s footfalls on a piezo-wired sidewalk!
With all those alternative sources of energy, what next?

Visit the web site www.hu.mtu.edu/~hlsachs where you can listen to two stories, read a third, read reviews, and find links to the publishers of my books.

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