There's also the "graph on average paid vacation time in industrialized countries:" which is actually mandated vacation. I'd be very interested in seeing the 'average' graph to compare.
I was being facetious. I didn't really stop reading until I read this:
understand that we cannot control the incoming information you will
disclose to our representatives in the course of entering, or what our
representatives will remember about your entry. You also understand that we will
not restrict work assignments of representatives who have had access to your entry.
By entering this Contest, you agree that use of informationin our representatives’
unaided memories in the development or deployment of our products or services does
not create liability for us under this agreement or copyright or trade secret law;
Sounds like a filthy, under-handed way of saying "we won't copy your code verbatim, but we reserve the right to copy your algorithm and not even give you credit for it".
To increase the value of ending up on a Top 10 or Top 100, they should provide purchasers with more opportunity for exposure, including logotypes, presentations and links to websites.
Excellent point, but it shouldn't impact an A/B test. Specifically, the experimental and control users should be equally drawn to look at the deactivation page.
However, this could give a false impression of improvement if you just look at the data before and after the launch. It's a good reason to also look at the total number of deactivations / visits to the deactivation page.
Less closet space being wasted. It's nearly 2AM, so I'm not as coherent as I'd normally be. Though if you have an overly packed closet, it could result in some garments needing to be ironed more from being crammed together all the time.
I think it's a bad example. More clothes mean you will do laundry less often but have bigger loads when you eventually do, while having fewer clothes means doing laundry more often.
I wish I had been. I heard a car crash last night, and when I got downstairs, it became clear that someone had hit a parked car (hard) and was fleeing the scene. I actively tried to catch the license plate, but could only pick up the first three characters, and even those I'm not confident of. Not sure if 15fps on 480x320 would have helped (especially in bad lighting), but I'd love to have that footage and find out.
I know you're being sarcastic, but I actually saw this coming and invested a fair amount in kneezles. Now I wish I'd just bought kneezle options, since I could have gotten much better leverage.
I really would like to write a more articulate reply, but it's late and I'm tired, so I'll leave you with:
I don't believe you.
Portable electric heaters can be incredibly efficient, since they only heat the room in question. I don't know much about building materials, but the article suggested that most heat loss is through windows, so worrying about wood building seems unnecessary.
Water conservation discussion need to be very localized. Lots of places in the US have very low population densities and plenty of water. Conservation is silly in this case. Whether your toilet uses a lot of water or a little, the same amount of poop and same amount of water are going to end up back in the river. Besides all this, toilet flushing and ice in drinks is peanuts compared to agricultural usage. They are little things and do not make a huge difference.
I had a look through your sources and they convinced me that you were wrong about water conservation. Even if lots of places have low density and plenty of water, there are negative effects.
Surely using as little as necessary, most of the time, is a good policy.
"Per capita residential water use in the United States is more than four times as high as in England and five times as high as in Germany."
There are many conclusions you can take from that, but a common one would be: Many people in the US use more water than necessary.
In terms of buildings, my experience with houses in Australia (almost zero insulation, single glazing) and northern Europe (astonishing volume of insulation, triple glazing standard) also suggests that there is something to think about here.
I'm not sure that this is what jvdh had in mind, but any pure-heating device is by definition 100% inefficient. Any physical device which does work produces heat as well (well eventually. The energy may feed into other processes before it ends up as heat). A 100% efficient device is one that produces work equal to the amount of heat (I think - my thermodynamics is a little rusty). A pure heater produces heat without doing any work whatsoever with the energy.
The most efficient heating would be done either by a heat pump (backwards air conditioner), or by doing some work with it.
Your point about heating only the rooms required is quite true, though. portable heaters may be more efficient than other extant kinds of heater. One other disadvantage is that many of them are air heaters, and the human body is more sensitive to radiant heat than air temperature. (It feels a lot better to be warmed by the sun, than to breath warm air).
There are portable radiant heaters, though far less of them around than there used to be. I think people see them as less safe, which I guess they are.
An electric heater is inefficient if the electricity was generated inefficiently.
Inefficient: burn methane at a central point running a steam engine generator, dumping tons of waste steam into the air, run the electricity to your house and turn it into heat there.
Efficient: pump methane to your house and burn it there.
More efficient: burn the methane at a central location running a steam engine generator, carry both the steam and the electricity to your house, heating it and running appliances.
The moral: live densely enough that steam pipes are practical.
My thermodynamics is rusty as well, but from experience I can say that using a central heating system where hot water is pumped through feels a lot better and seems a lot more efficient than an electric heater.
"Water conservation discussion need to be very localized."
I live in Michigan. Tomorrow my car is going into the dealership to be examined to see if the flood it was in last week damaged it in any subtle ways, then it needs to be cleaned up since I wasn't quite able to get it dry enough to avoid it smelling.
This snapshot gives you a reasonably accurate idea of our relationship to water around here. (I'm smart enough to live where it won't flood, unfortunately my work office is built in a flood plain, albeit on stilts so the main office won't flood, I was out to lunch, bit o' rain pops up, bam.)
I live in the Netherlands, we have an abundance of water here.
The point is not the availability of water, it is the availability of fresh water. Most of the time it takes a lot of work to treat water in such a way that it suitable for consumption.
And then there's the waste water processing. You can't just dump your waste water in nature, it has to be processed first, which takes some effort as well.
Should I be considering this differently from solar? They're both harvesting ambient EM radiation; and the energy density of solar is much higher. I guess that radio goes through walls and never sleeps, so that's a plus. Anyway, I thought that the mentioning of a solar calculator was quite appropriate and warranted further discussion.
It sounds like the device on the hard hat is more like a passive RFID chip; It's hard to be sure, but the article says all the dangerous equipment has transmitters of their own.
Of course, the effective difference between the passive RFID chip and a device that simply consumes ambient radio-spectrum EM radiation is small, mostly a paradigm change.
Your initial question begets an interesting question- since light is EM radiation, just like radio waves, shouldn't we be able to pick up light with an antenna? If we can figure that out, we can forget about solar cells with their sad efficiency levels.
edit: with some quick research, the answer is obvious; while it seems extremely weird to imagine, light can be absorbed by an antenna- and the first and foremost reason this isn't being done already is because the appropriate antenna would be ~700 nanometers long.
You can absorb EM radiation just fine with an antenna that's "too long". It's when it's too short that you run into problems.
500nm-wavelength light oscillates at about 600 terahertz, with a period of about 1.7 femtoseconds. If you want to rectify that and turn it into DC current so you can run current semiconductor devices, you need a diode that can switch on once and off once in that period of time. So your forward recovery time plus your reverse recovery time needs to total less than 1.7 femtoseconds. Among other things, I think this implies that the depletion region in the diode needs to be less than 0.9 femtoseconds in width --- at the electron drift velocity of the semiconductor, which I think is typically around 12 orders of magnitude less than c, although in silicon it can be as high as only three orders of magnitude less than c. Which means that your depletion region needs to be 3 orders of magnitude smaller than the wavelength. Unfortunately the wavelength we're talking about here, at around 1000nm, is only four orders of magnitude bigger than a smallish atom, at 0.1nm. So you're pushing up against the bounds of possibility here with an insulating depletion region of a few atoms in thickness.
Forward and reverse recovery times for silicon diodes vary widely. Typical values for discrete components are measured in the tens to hundreds of nanoseconds. Schottky diodes bring that down to tenths of nanoseconds. One nanosecond is one million femtoseconds, so that's still five orders of magnitude too slow.
Anyway, I don't know anything about this stuff, really.
Seems like it'd be easier to just drive a 600 terahertz motor, if such a motor can be made, and use that to drive a good old fashioned 60hz generator.
The silicon would be a much nicer solution though. Thank you for the details on the diodes, I forgot about that part. You're probably right on the diodes being the hold-up.
Now that's an interesting idea. The light contains an oscillating magnetic field that you could use directly to spin a permanent magnet, if you had one that was small enough. (Any atomic nucleus would do, but you can't connect a shaft to it.) Maybe you could build a multipole nanomotor so that the rotor itself doesn't have to spin at 600THz; if you have 100 poles, which is not that far out of what people commonly do with macroscopic stepper motors, then you could get the rotation down to only 6THz. (But then you're only potentially absorbing light at the rim of this rotor.)
Gearing that down to 60Hz at the nanoscale — without losing most of the energy to friction — could still be a significant challenge. I don't know of any hundred-billion-to-one gearboxes.
The basic difficulty with the nanomotor approach, I think, is that electrons are lighter than nuclei, so it's easier to get them to oscillate over useful distances in any particular frequency range, and this is especially tricky in the terahertz to petahertz frequency range. A nucleus, under the influence of the same electrical field as an electron, will accelerate about three or four orders of magnitude more slowly.
Ultimately this should be a scale advantage for mechanical computation, since it means you can localize an atom to a much smaller region, given a certain momentum uncertainty, than an electron. The atom can't tunnel as far, so it can store a bit reliably in a much smaller region. I don't think we're there yet.
Is it necessary to make it a nanomotor? Friction is not a concern once you have things suspended by magnets in a vacuum. If power is an issue for driving the larger rotor, instead of using just one antenna use an array. It's typically better to have one giant Engine than many small ones.
Forget gearboxes, a belt drive would be superior until you start cranking out huge power, and in that case you could try chains instead. Also, don't forget that a 60hz motor does not have to spin at 60rpm to generate 60hz.
The difficulty with making it larger than nanoscale is that the centripetal acceleration becomes very great, which makes holding a large rotor together tricky; you need very strong materials. Actually, I did the calculations, and for visible light, it isn't even feasible at the nanoscale.
The centripetal acceleration of the rim of a rotor of radius r is rω². Rotating at 600THz (i.e. 600 trillion rotations per second), ω = 600T2π/s ≈ 3.8 × 10¹⁵/s. If your radius is 1mm, then your acceleration is about 1.4 × 10²⁷ G. The smallest rotor you can make out of atoms is probably around 0.1nm, which reduces the acceleration to only about 1.4 × 10²⁰ G. If your rotor was, say, an orthohydrogen H₂ molecule, with a distance between the nuclei of about 62pm, and thus a radius of about 31pm, the acceleration is about 4.5 × 10¹⁹ G, which would be a weight of about 74 micrograms pulling on that single covalent bond. The nuclei would be whirling around the covalent electron cloud that bound them together at about 11.7 kilometers per second, and each of them would have about 1.13 × 10⁻¹⁷ J of kinetic energy. Unfortunately, hydrogen's ionization energy is about 2.2 × 10⁻¹⁸ J, so that's about five times as much energy as you'd need to rip the molecule apart. I think. It could work out in the infrared, maybe. You'd just need a way to get the molecule started spinning.
So I guess you'd have to make your rotor a lot smaller than a diatomic molecule, or a lot stronger than a mere covalent bond.
Generally a 60Hz generator must spin at 360rpm or slower to generate 60Hz.
Wouldn't 700 nm antennas would be easy to make? We've been fabricating features smaller than that on silicon wafers since 1994 (according to Wikipedia).
Original source of the graph (afaik): http://www.cepr.net/documents/publications/2007-05-no-vacati...