The Voyager spacecraft (among many others) were powered by a Radioisotope thermoelectric generator. This sounds pretty cool, although admittedly not as cool as a Triaxial Fluxgate Magnetometer. The RTG works using the Thermoelectric effect, creating a temperature difference using a suitable radioactive material. It has the supreme advantage of not having any moving parts, resulting in very good reliability. Unlike solar cells, they can be used anywhere in the solar system, or beyond. Unlike conventional batteries, they will produce power for decades.
It is important to remember that these kind of amazing devices would not be possible without suitable models of metals, radioactivity etc. I guess this is one of the many reasons we study Physics, and especially solid state physics...
On a complete side note, according to wikipedia (the source of all knowledge and truth), the copyright holders of the music and images on the golden record placed on the voyager spacecraft "signed agreements which only permitted the replay of their works outside of the solar system." I find it absurd that such a distinction need be made.
Does anyone else know of some other cool applications of the stuff we've learned so far?
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Nothing really cool was found. An obvious application of the hall effect is used in Hall probes/ magnetometers to measure magnetic fields. Basically, put the probe in the magnetic field and measure the transverse voltage. Its probably not the most sensitive way to measure magnetic fields because even for a metal plate of thickness 1mm, typical electron density of the order 10^28 per cubic meter and a current of 1A, the voltage produced in magnetic field of 1 Tesla is only of the order of 10^-7 V.
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Hall effect transducers -- there's a nice little description on them here: http://www.scientificamerican.com/article.cfm?id=how-do-hall-effect-transd
Essentially something that turns a magnetic field measurement into something useful.
They mention application of keyboards...keyboards are pretty useful.
An application of Hall-effect transducer is to measure forces acting on tendons and ligaments in vivo.
Interesting review (Hall-effect transducer Section 2.2): http://www.sciencedirect.com.ezproxy.library.uq.edu.au/science/article/pii/S0268003304000221
Measuring forces on tendons seems like a bizarre curiosity, but it would be great when designing prostheses, structuring surgery or even just correcting posture -- thoughts quickly goes to knees, feet, hands.
I like how all this physics stuff just happens to come into our lives!
Dave:
ReplyDeleteI always wondered how the nuclear batteries worked! I suppose it must be the most efficient solution for low power outage/low outside temperatures?
The Hall-effect is pretty useful but I think that many applications may not be straightforward uses but rather derived uses.
The Seebeck effect is used quite a bit, though. I think the most useful application of it is efficient heat engines/refrigerators, although I can't think off the top of my head the examples I knew before.
I would disagree with you, Ann, on the usefulness of measuring tendon forces: without being able to measure these, some of the most important parts of the body for weight-bearing and locomotion would probably need surgery to measure. An example would be if someone damaged their Achilles tendon; without this, you would not be able to check if your leg had recovered enough for full use (this level of detail would be necessary for really important things like space mission candidates).
Keyboards are useful, though! It would be interesting to make a kind of solar keyboard that utilised the Seebeck/Hall effect to generate the current required to send a signal, removing the need for a power source (but meaning you need the sun!). Perhaps it could work for laptops, since you can get a heat source...?
Cool Application of the Drude Model: The moustache on the Honours room board.
Cool Application of Fermi-Dirac Statistics: Our friendly neighbourhood jumping spider, named Fermi.
Obviously I would feel uncomfortable if something had to be stuck inside of me just to measure something on a little tendon.
DeleteTheir use would be limited to the the comfort and design, but at least in vitro, to measure small materials, e.g. protheses, it would seem useful.
if you could get a device small enough, it would be promising...
What moustache? how many spiders are there?