Do you realize that fluoridation is the most monstrously conceived and dangerous Communist plot we have ever had to face?
General Jack D. Ripper
Dr. Strangelove, Or: How I Learned To Stop Worrying And Love The Bomb
For children whose adult teeth haven’t shown yet, fluoride still improves tooth enamel, the highly mineralized tissue on teeth’s surface. Fluoride also helps teeth damaged from the decay process and breaks down bacteria on teeth.
Excellent discussion of the difference between a global warming skeptic and a denier. I don’t think the author misses anything.
Alas, a much larger number use the term “skeptic” as a re-labeling trick, while wallowing in the standard narratives of distraction and delay, exhibiting patterns described in Michael Shermer’s Why People Believe Weird Things and Carl Sagan’s The Demon-Haunted World. Only now, as more recently related in Chris Mooney’s The Republican War on Science and in Denialism, by Michael Specter, the trend toward dismissal of science has gone into overdrive, propelled by forces that are intensely political.
So here is the problem: What discrete characteristics distinguish a rational, pro-science “climate skeptic” who has honest questions about the AGW consensus from members of a Denialist Movement that portrays all members of a scientific community as either fools or conspirators?
There are a number of stories about this, and for most of them the technical explanation starts and ends with “The structure works similarly to a magnifying glass that intensifies light from the sun — except in this case, the lens intensifies wind flow” or something similar. Which is really frustrating. This story doesn’t, and even provides a link to the university web site, so perhaps we can glean additional information from that.
OK, it looks like this “lens” is a venturi of sorts. I’m neither a fluid mechanic nor an aeronautical engineer; I imagine the compressibility of the air makes this a little different for air than for water. But when you restrict the area of flow, the speed increases. Put another way, by funneling/focusing you increase the energy density of the air, so more energy is present within the area of the turbine and you can extract more energy without making the blades bigger. That much I get. I’m not sure if this accounts for all of the increased efficiency or if there are other effects as well, like improved efficiency by generally having higher speeds. It certainly doesn’t look like you are tripling the capture area from the pictures.
The stories tout this as being great, but I notice that the turbines are ~1 kW, as opposed to commercial turbines which are MW-ish beasts, and the researchers do not say how far this effect will scale up, and in fact caution that it will not. The bits about how these might be less objectionable on aesthetic grounds don’t sway me — there’s no justification that these will look pretty to those who disapprove of regular turbines. So I’m not seeing these as “farms” and >100 m diameters would seem to exclude them as being put up in your yard.
A Stanford mechanical engineer is using the biology of a gecko’s sticky foot to create a robot that climbs. In the same way the small reptile can scale a wall of slick glass, the Stickybot can climb smooth surfaces with feet modeled on the intricate design of gecko toes.
If you watch the video, you might notice that they appear to have edited out a section discussing the need for a tail — the only kept the part when they added the tail and tell us the “now stickybot can climb.” It’s too bad, because I think there’s a bit of interesting physics there. It’s mentioned briefly in this video, where you can see a real gecko with its tail pressing against a surface, the hind legs acting as a fulcrum, so that it can move its upper body back toward the surface.
Some outstanding slow-motion combustion, thermodynamics, and safety advice. Half a gram of water turns into about a liter of Hydrogen + Oxygen. Then, boom!
[W]hen H2 and O2 burn, there is actually a reduction in the number of molecules of gas, which would, if all other conditions were the same actually produce a reduction in pressure, however the temperature of the exhaust gas is not the same, it goes from about 300K to 3000K which in a confined system would increase the pressure from about 1 to 10 atmospheres. This is getting close to the failure threshold of these bottles, and also represents a significant rate of release of energy.- caution is required, and this really isn’t something you should be trying unless you really know what you are doing.
While the potential for cheaper energy could increase the quality of life for billions around the globe, it also could mean an increase in energy usage. Tsao says that since the 16th century, with each revolution in lighting technology humans have used more light, instead of using the same amount of light for cheaper.
“Over the past three centuries… the world has spent about 0.72 percent of the world’s per capita gross domestic product on artificial lighting,” said Tsao. “This is so for England in 1700, in the underdeveloped world not on the grid and in the developed world using the most advanced lighting technologies. There may be little reason to expect a different future response from our species.”
So let’s blame the LEDs for human nature and the law of supply and demand.
In this type of [scanning tunneling microscope], a single hydrogen or deuterium molecule is attached to the probe tip, and the team showed that the pressure of this molecule against the probe leads to the dramatic improvement in imaging. The technique images the effect of a force on electrical conduction through the probe, which allows a more complete picture of the molecule’s electrons than standard STM provides.
Penultimate means “second to last.” It does not mean “better/cooler than ultimate,” in the opposite way that you might use infamous instead of famous. (It doesn’t mean an arbitrary one in a group, either)
Google on penultimate guide and you’ll see a plethora of piñatas of misuses.