The frequencies used induced harmonics in electric streetlamps which were all across the shortwave region of the spectrum. I can only assume that they're using a different frequency (lower bandwidth) or that they have a filtering plan for the public lighting systems.
The fragility of fibre is overstated. I have 5 types of fibre on my lab bench, 'bare' single mode fibre. This is fragile, a touch with a razor blade then bending it is how I cut it so I can join it again with the fusion splicer. I also have some jacketed single mode fibre, which is pretty tough, you can cut it with wire cutters though. There's some strange bits of multimode fibre which are about the same as jacketed single mode, but then there's a bit of telecomms fibre. It's tough stuff, I've looped a bit of spare over my chair and I can stand on the loop. I'd test the affect on transmission but my rig has something more important in it currently.
In summary, the glass is fragile, but strong. With a proper coating it is tough and strong.
Pretty crap for what I'm doing, requiring several data aquisition cards (using windows for that). Also no OS X native Matlab yet, meaning I have to switch to (yuck) classic. (I just go and use a SPARCstation).
That said, TeXShop is a great app, I'm doing all my writeup on my PowerBook. Not science though;)
What the mac is good for is not specifically science yet, it just happens that scientists regard computers as tools and aren't as tolerant of crashes, and don't always have the time to play with the OS.
(I do have a dual CPU IBM netfinity for playing with Linux on;)
I'd certainly expect the AGP bus to be used asymmetrically, how often do you want to do high speed data capture with a card that's primarily output?
The only situation I can see where you'd want more than PCI bandwidth returning would be for uncompressed HDTV capture, and there are better ways to do that (grab the raw broadcast stream for example)
Heh, I remember at school when we got our first Windows 3 machines, some guy was certain you could translate to greek by typing in English then setting the 'Symbol' font.
A friend of mine has been working on organic solar cells for the last 4 months (MSc Project), he's hoping to reach 4% efficiency. Last time I spoke to him he was just about to put the ITO transparent contacts on, then test it with different wavelengths of light.
The possibilities of making organic solar cells have been considered almost as long as organic LEDs have been known (one of my professors was in the Cambridge group who discovered the effect) but the efficiency will probably never be near that of good polycrystaline silica.
To power my laptop I'd need half a metre square of high grade solar cell, about £500...
This is precisely what I've done already. Yummy tibook. I have got Debian as well, but I've not actually felt the need to use it, OS X is *that* good.
Not looking back...
Of course, the worry about Apple is they are the only source of mac's, and they'll be subject to any DRM laws if (when) they get put (paid) through the US govt.
Install Quicktime for windows. Look at it. Can Apple write decent windows software?
Personally I think not. They can create great hardware, and good software for their own OS, but I don't think it's worth their while coding windows stuff.
Telecomms operates around 1550nm, because that's where fused silica fibre is the most transparent, and has low dispersion. We can see up to about 740nm.
Note that in ideal conditions (perfect lens etc) light diverges at an angle related to its wavelength and the minimum point, the longer the wavelength, the faster it diverges.
The light coming out of a typical FC connector diverges at about 60 degrees and the beam is pretty crap*. Even coupling between two properly cleaved fibres with a sub micron air gap loses more than half the signal.
To get any signal out of the noise out there you'd *have* to use a lock-in amplifier. These are not trivial to make, unless you have training and/or experience. These 'lock-in' to a regular signal, you'd have to modulate the laser to this signal, and the data on top of that modulation.
What you want is a laser which outputs a TEM00** beam, a collimator with a large lens, a good external light modulator and a lock-in amp. At each end. Then you have to modulate the laser with carrier and data, from some kind of device. (Start with a serial or parallel port, nice and easy)
* Technical term. Take too long to explain:P ** Transverse Electromagnetic Mode 0,0: the most basic gaussian mode of a normal cavity laser. The easiest to focus, as it is a self-fourier-transform. Unfortunately the more power you want out the more likely it is you'll get power in the other, less clean modes.
I'm a physicist specalising in optics and photonics, and I'm also quite dubious about the application. Unfortunately the guy in the department who specialises in optical computing seems to be hiding so I can't get his comments.
The non-linear self focussing is real; I've seen nice bits of broken laser components where this has occured. The interaction they mention could also happen within a nonlinear material.
I can kinda see how the surface tension-like effects could occur, each photon disturbs the material it floats through, at certain powers you could imagine it making it easier for other photons to travel in its 'wake', making it clump up. (The difference between 'droplets' and 'solitons' is unclear to me. I play with lasers. Burn things good!)
I am dubious about the data storage. These droplets are still moving at a significant proportion of c, and presumably there is also loss.
I suppose you could have a ring EDFA* of a known circumference and push bits in, drop bits out. I'd love to try it:)
On the whole I'd say you're being overly cynical. The AIP is a well respected organisation.
* EDFA: erbium doped fibre amplifier, I'm sure you telecomms and big networking guys know. In this case it just makes sure the droplets don't 'evaporate'
Slashdot Mirror
You're correct zen old mate :P
The frequencies used induced harmonics in electric streetlamps which were all across the shortwave region of the spectrum. I can only assume that they're using a different frequency (lower bandwidth) or that they have a filtering plan for the public lighting systems.
Maybe I'll get a file at the FBI or CIA now.
Note: subject unusually fond of cows.
There's plenty to fiddle with, I've compiled ipv6 (KAME) into my OS X kernel, and have managed to get a few of the userspace apps working as well.
And all the while, I had a machine I can write my notes up on, and impress women*.
* It's true. Alas she was 50+
Heh, I don't have a "proper" job, I'm paid about £8000 per annum to play with lasers, optical fibres etc.
Postgrad student. I should probably put it in my profile, only it's ending in a month.
The fragility of fibre is overstated. I have 5 types of fibre on my lab bench, 'bare' single mode fibre. This is fragile, a touch with a razor blade then bending it is how I cut it so I can join it again with the fusion splicer. I also have some jacketed single mode fibre, which is pretty tough, you can cut it with wire cutters though. There's some strange bits of multimode fibre which are about the same as jacketed single mode, but then there's a bit of telecomms fibre. It's tough stuff, I've looped a bit of spare over my chair and I can stand on the loop. I'd test the affect on transmission but my rig has something more important in it currently.
In summary, the glass is fragile, but strong. With a proper coating it is tough and strong.
I slipped into a rant: my other comment re: lack of high quality acquisition cards still stands.
yeh, but our department refuses to order it as there are only 4 boxes running X currently.
Pretty crap for what I'm doing, requiring several data aquisition cards (using windows for that). Also no OS X native Matlab yet, meaning I have to switch to (yuck) classic. (I just go and use a SPARCstation).
;)
;)
That said, TeXShop is a great app, I'm doing all my writeup on my PowerBook. Not science though
What the mac is good for is not specifically science yet, it just happens that scientists regard computers as tools and aren't as tolerant of crashes, and don't always have the time to play with the OS.
(I do have a dual CPU IBM netfinity for playing with Linux on
From http://www.pgp.com/display.php?pageID=21:
PGP Corporate Desktop 8.0 for Mac OS X will be available for ordering in Q4 2002.
I'd certainly expect the AGP bus to be used asymmetrically, how often do you want to do high speed data capture with a card that's primarily output?
The only situation I can see where you'd want more than PCI bandwidth returning would be for uncompressed HDTV capture, and there are better ways to do that (grab the raw broadcast stream for example)
Some more right wing danes are/were lobbying to make it harder for germans to buy property in .dk, so I'd imagine that there are some.
Heh, I remember at school when we got our first Windows 3 machines, some guy was certain you could translate to greek by typing in English then setting the 'Symbol' font.
Laurence Brice, are you still out there. heh.
Sure you will, just grab the pent' first.
The pollution in the air starts settling out and eventually it's only possible to survive up sky scrapers.
Can't recall the name, but the collection I read it in was 'The Ghost Light'
The NPL (UK version of NIST) tested a variety of software used for scientific purposes, some of the results are in Metromania 13.
As you know how long it is supposed to be:
dd if=[file] of=[new file] bs=1 count=[length]
I strongly suggest rebuilding the affected filesystem, that kinda weirdness can be indicative of deeper problems.
Lifetime is longer for solar cells as the electric fields are lower.
I doubt that a $3 solar cell would provide enough current to run a palmtop. Find the wattage requirements, solar cells are approx £10 per watt.
A friend of mine has been working on organic solar cells for the last 4 months (MSc Project), he's hoping to reach 4% efficiency. Last time I spoke to him he was just about to put the ITO transparent contacts on, then test it with different wavelengths of light.
The possibilities of making organic solar cells have been considered almost as long as organic LEDs have been known (one of my professors was in the Cambridge group who discovered the effect) but the efficiency will probably never be near that of good polycrystaline silica.
To power my laptop I'd need half a metre square of high grade solar cell, about £500...
Dear oPless.
"You've been trolled"
However, it's brought some interesting links to light.
Yeh, it's a great big fuckup.
They're not as good as british currency for completely blind people either. ISTR that all coins are round, unlike our system:
small, thin, round, smooth: 1p
large, thin, round, smooth: 2p
small, thin, round, rough: 5p
large, thin, round, rough: 10p
small, thin, 7 sides, smooth: 20p
large, thin, 7 sides, smooth: 50p
small, thick, round, rough: £1
large, thick, round, rough: £2
It's free for me, I've never paid tax in the US.
This is precisely what I've done already. Yummy tibook. I have got Debian as well, but I've not actually felt the need to use it, OS X is *that* good.
Not looking back...
Of course, the worry about Apple is they are the only source of mac's, and they'll be subject to any DRM laws if (when) they get put (paid) through the US govt.
Install Quicktime for windows. Look at it. Can Apple write decent windows software?
Personally I think not. They can create great hardware, and good software for their own OS, but I don't think it's worth their while coding windows stuff.
Telecomms operates around 1550nm, because that's where fused silica fibre is the most transparent, and has low dispersion. We can see up to about 740nm.
:P
Note that in ideal conditions (perfect lens etc) light diverges at an angle related to its wavelength and the minimum point, the longer the wavelength, the faster it diverges.
The light coming out of a typical FC connector diverges at about 60 degrees and the beam is pretty crap*. Even coupling between two properly cleaved fibres with a sub micron air gap loses more than half the signal.
To get any signal out of the noise out there you'd *have* to use a lock-in amplifier. These are not trivial to make, unless you have training and/or experience. These 'lock-in' to a regular signal, you'd have to modulate the laser to this signal, and the data on top of that modulation.
What you want is a laser which outputs a TEM00** beam, a collimator with a large lens, a good external light modulator and a lock-in amp. At each end. Then you have to modulate the laser with carrier and data, from some kind of device. (Start with a serial or parallel port, nice and easy)
* Technical term. Take too long to explain
** Transverse Electromagnetic Mode 0,0: the most basic gaussian mode of a normal cavity laser. The easiest to focus, as it is a self-fourier-transform. Unfortunately the more power you want out the more likely it is you'll get power in the other, less clean modes.
I'm a physicist specalising in optics and photonics, and I'm also quite dubious about the application. Unfortunately the guy in the department who specialises in optical computing seems to be hiding so I can't get his comments.
:)
The non-linear self focussing is real; I've seen nice bits of broken laser components where this has occured. The interaction they mention could also happen within a nonlinear material.
I can kinda see how the surface tension-like effects could occur, each photon disturbs the material it floats through, at certain powers you could imagine it making it easier for other photons to travel in its 'wake', making it clump up. (The difference between 'droplets' and 'solitons' is unclear to me. I play with lasers. Burn things good!)
I am dubious about the data storage. These droplets are still moving at a significant proportion of c, and presumably there is also loss.
I suppose you could have a ring EDFA* of a known circumference and push bits in, drop bits out. I'd love to try it
On the whole I'd say you're being overly cynical. The AIP is a well respected organisation.
* EDFA: erbium doped fibre amplifier, I'm sure you telecomms and big networking guys know. In this case it just makes sure the droplets don't 'evaporate'