Slashdot Mirror
Sticky Tape Found To Emit Terahertz Radiation
An anonymous reader writes with this excerpt from New Scientist "'Peeling sticky tape has already been shown to produce X-rays, so Joseph Horvat and Roger Lewis of the University of Wollongong in New South Wales, Australia, tried to see if it could create lower-frequency terahertz radiation. "We were rather pleasantly surprised to obtain a clear signal in our first attempt," says Horvat. Strongly adhesive Scotch Magic 810 tape and weakly adhesive electrical tape both yielded strong terahertz signals, ranging from 0.1 to 10 terahertz, but only about a microwatt of power, too little for practical use (Optics Letters, vol 34, p 2195). Horvat says that refinements should increase the power by orders of magnitude.' It may be old news to Slashdot that [peeling clear tape] had been proved to produce X-rays, but watching the linked video where they use tape to expose X-ray film was pretty amazing."
From now on, it's staples for everything.
So, does peeling duct tape emit gamma bursts?
Putting the "anal" back into "analyst"...
Is there a practical application for this? Does mechanically peeling tape require less power than producing the same radiation through more conventional means or with simpler materials?
I can appreciate the gee-whiz nature of it but I can't quite figure out what value it has outside of the sciencey aspect of it.
Doesn't sound odd to me at all. Last time I checked EVERYTHING emanated something in the Terahertz region of the spectrum. Its like infra-red in that its darn hard not to give off a signature of some kind. That's how you can use it in the airports for monitoring for hidden weapons without dousing people with all kinds of xrays. Things that are more dense give off more T-waves. If you peal tape off something it causes a release of energy, and part of that will be thermal, and part T-waves.
Strongly adhesive Scotch Magic 810 tape and weakly adhesive electrical tape both yielded strong terahertz signals,
I propose that we add two new fundamental forces to our physics lexicon - "strongly adhesive" and "weakly adhesive".
#DeleteChrome
Yes, you will have the power to mend small tears in sheets of paper. The magical ability to control paint to be applied in some areas but not in others along nice sharp lines. The super human ability to stop electricity from shorting between two wires.
Among other similar powers.
Paying taxes to buy civilization is like paying a hooker to buy love.
If anyone is curious about how this happens, it is due to the very high voltages developed on clear sticky-tape when it is unrolled. The peeling action tends to create a very uneven distribution of charges on the tape surface... the tape itself is a wonderful insulator, and as a result the charges cannot easily snap back to equilibrium states.
:-(
This causes very high voltages and, where the tape is just being unrolled from the roll, extreme electric field as the distance is so small. (Remember, Electric field is measured in V/m!). Charges arc through the air easier than they can travel through the tape, so you get all sorts of emissions from this miniature lightning storm as the voltage drops back to a static level of 'only' about a kV.
Incidentally, this is why you should always use special ESD-approved tape when working anywhere around electrostatic-discharge-sensitive devices. My company's ESD training class had some quite interesting demonstrations where stuff was destroyed with a single piece of freshly unrolled tape. Unfortunately for me, I had yet to learn that lesson in graduate school, and so I ruined many a sensitive analog ASIC by taping a supposedly protective dust cover over the bare IC* (we were too cheap to pay for the black packaging that most people call a "chip").
*Note to all the pedants out there: Yes, a fabricated IC has its own natural shield of silicon dioxide (glass) on top of the deposited layers, however the tens-of-micron-thin wire bonds that connected the IC to my prototyping board were exposed to air, and could easily be broken--or worse, shorted--by errant dust particles.
>> Standing on head makes smile of frown, but rest of face also upside down.
I can see al qaeda ordering boat loads of it for a mass suicide tape pulling! Does this also mean tape may be declared a weapon of mass destruction ;)
http://www.writeitfor.us - Writing IT for the IT generation.
You can test this yourself with a mass spectrometer. All farts are methane; that's why you can light 'em. Cow farts, cat farts, people farts, etc. That smell that shit produces is methane and bacteria.
Methane is odorless, so no. And that is not the only factual error in your post. Methane is uncommon in flatulence (most livestock methane emissions are from belching, not farting). Most flatulence is nitrogen, and carbon dioxide. The smell comes from volatile organic acids and reduced sulfur compounds produced in protein breakdown.
TLDR version: You're talking out of your ass, and it stinks because you eat too much meat.
Generating terahertz radiation, especially coherent Terahertz radiation, is hard because the frequency (around 300GHz - 20THz) is too low for conventional solid-state laser technology and too high for conventional electronic antennas. And it is potentially useful for a range of applications such as nondestructive high-resolution imaging (for e.g. materials, medical, and security applications), spectroscopy, or opening up new communications bandwidths. (Google "terahertz applications" and you'll find a lot of links.)
There are a number of terahertz sources that are becoming available, from optical rectification schemes to free-electron lasers, but they have a tendency to be bulky and inefficient, so a lot of researchers are looking for alternative generation schemes.
That being said, I suspect that the terahertz radiation produced by sticky tape is incoherent, which would severely limit its utility in practical applications. (Quite apart from the efficiency, which sounds like it is currently very low.) That doesn't mean that it isn't interesting from a basic science perspective, of course.
If a thing is not diminished by being shared, it is not rightly owned if it is only owned & not shared. S. Augustine
Eeep! /me dons tinfoil hat. /me realizes tinfoil is matter
D'oh!
I don't know if I should fear or welcome the day conspiracy theorists spontaneously all decide that tinfoil is out to get them.