Category Archives: Tech

MIT Tea

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No joke: This is the biggest battery breakthrough ever

The key to this new technology is that the metals that would normally be solids in a conventional battery have been broken into nano-size particles that are suspended in a liquid. The batteries, known as “semi-solid flow cells,” store their power in a black gunk that looks like motor oil, which has earned it the nickname “Cambridge Crude.” Because charge is stored in this liquid, it would be possible to “fuel up” an electric car with charged liquid electrolyte, just like fueling up at a conventional gas pump.

That’s pretty neat.

Planes, Trains and Automobiles … and Airships?

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Helium Hokum: Why Airships Will Never Be Part of Our Transportation Infrastructure

[A]irships got left behind. Why? They have an Achilles’ heel. No, it’s not the weather, hydrogen, or the materials of the day—and it’s not some conspiracy or a crewman with a bomb on the Hindenburg ruining it for everybody. Like a lot of things, the facts are simple and scientific, and thus boring—unless you’re intrigued by simple scientific facts. Either way it’s this: airships are inefficient.

The purpose of transportation is to get a thing from one place to another. The measure of any vehicle’s efficiency—be it by land or by sea or even by air—is how much it carries vs. how hard you have to push it and how fast it goes. At the end of the day, we all want to get it there fast, and we all want to get it there cheap.

If You Build it, Fingerprints Will Come

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Fingerprints Go the Distance

Slightly smaller than a square tissue box, AIRprint houses two 1.3 megapixel cameras and a source of polarized light. One camera receives horizontally polarized light, while the other receives vertically polarized light. When light hits a finger, the ridges of the fingerprint reflect one polarization of light, while the valleys reflect another. “That’s where the real kicker is, because if you look at an image without any polarization, you can kind of see fingerprints, but not really well,” says Burcham. By separating the vertical and the horizontal polarization, the device can overlap those images to produce an accurate fingerprint, which is fed to a computer for verification.

I’m guessing that what they mean is that the light source is polarized and the cameras have polarizing filters in front of them to see the two components. Reflectivity generally depends on the polarization and angle of the incident light; the whole reason that polarized sunglasses are effective is that light scattered off of a surface tends to be polarized parallel to that surface, and at Brewster’s angle absolutely none of the perpendicular component will be reflected. So it seems reasonable that detection of the two polarizations improves the contrast of the image you get. Light at normal incidence will reflect the polarized light with no change, but light scattered off of the valleys will mix in some of the orthogonal polarization, which gets picked up by the other camera.

Please Take a Math Class

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Americans say ‘no’ to electrics despite high gas prices

Nearly six of 10 Americans — 57% — say they won’t buy an all-electric car no matter the price of gas, according to a USA TODAY/Gallup Poll.

That’s a stiff headwind just as automakers are developing electrics to help meet tighter federal rules that could require their fleets to average as high as 62 miles per gallon in 2025. And President Obama has set a goal of a million electric vehicles in use in the U.S. by 2015.

I’m assuming that journalism school covered metaphorical statements and the author used “stiff headwind” as he meant to.

That statistic presumably means ~40% are open to the idea. The US adult population is more than 200 million people, so in what world is a group of 80 million potential electric car drivers less than the 1 million needed to reach that goal, thus representing that stiff headwind?

Way down at the end, it is noted that

Nissan interprets the poll numbers as a good sign, pointing out that “as many as 40% are considering driving electric vehicles.”

While math is the obvious problem here, I don’t think it’s the larger issue, which is that of spin. The author/headline writer wanted to cast the story in a negative light and so they leveraged the existence of a slim-margin majority to make a statement. People resisting change really isn’t news. I wonder if they had done a poll around 1900 about the enthusiasm for driving an automobile, what kind of results they would have gotten.

A Project not Requiring Japanese Steel

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Kill Math

A project investigating a different way to present math and manipulate mathematical information, leveraging today’s technology.

The power to understand and predict the quantities of the world should not be restricted to those with a freakish knack for manipulating abstract symbols.
…
We are no longer constrained by pencil and paper. The symbolic shuffle should no longer be taken for granted as the fundamental mechanism for understanding quantity and change. Math needs a new interface.

The site contains an interesting premise — the problems with math instruction aren’t limited to the methodology (a problem pointed out in any number of Vi Hart videos), but also the material itself:

school math is useless, kills inspiration and curiosity, is mind-numbingly tedious, makes no connections to anything, and is forgotten immediately after the test. It’s all negative.

which is also often true of science instruction.

Make sure not to miss

— The animations in the section “A Possibly Embarrassing Personal Anecdote,” which are pretty neat — as visualization of the integral, but also an intriguing visualization of an equation

— The video Interactive Exploration of a Dynamical System, which shows a model of a predator-prey system and the ways one can manipulate the equations to visualize how the variables behave.

See Sack

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Not sure why the Chip-Scale Atomic Clock (CSAC) is making news again; this seems to be a rehash of news from January, but it’s an opportunity to make a few comments.

One of the sessions I attended at the recent timing conference discussed some of the pros and cons of the new competitors to the traditional quartz oscillator, one being the CSAC and the other being microelectromechanical systems (MEMS). CSACs have a niche because of the desire to optimize on several variables such as cost, power, stability, and startup requirements. A good quartz oscillator, for example, needs a relatively long warmup time, and the ones with good stability are expensive and tend to drift a bit. So there’s room to beat it on some variables, depending on what the user needs vs. what s/he doesn’t care about, e.g. power and size are variables that matter for a portable system but not for a server rack.

One of the observation is that CSACs could soon find their way into computers tied into ultra-high speed networks, because the clock performance becomes a limiting factor in data transfer — you can send data at a higher frequency and you spend less time re-synchronizing the clocks.

Another observation was a reminder that DARPA is currently funding another program to drive the size and power down even further.

Hotels are Going All Hitchhiker

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They want to know where their towel is. All of their towels.

RFID Tags Protecting Hotel Towels

A more recent system, still not widespread, is to embed washable RFID chips into the towels and track them that way. The one data point I have for this is an anonymous Hawaii hotel that claims they’ve reduced towel theft from 4,000 a month to 750, saving $16,000 in replacement costs monthly.

Don’t steal any more Beverly Palm Hotel robes, Axel Foley.

The Market Won't Take Care of That?

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Video: They Sure Don’t Make Pyrex Like They Used To

When World Kitchen took over the Pyrex brand, it started making more products out of prestressed soda-lime glass instead of borosilicate. With pre-stressed, or tempered, glass, the surface is under compression from forces inside the glass. It is stronger than borosilicate glass, but when it’s heated, it still expands as much as ordinary glass does. It doesn’t shatter immediately, because the expansion first acts only to release some of the built-in stress. But only up to a point.
One unfortunate use of Pyrex is cooking crack cocaine, which involves a container of water undergoing a rapid temperature change when the drug is converted from powder form. That process creates more stress than soda-lime glass can withstand, so an entire underground industry was forced to switch from measuring cups purchased at Walmart to test tubes and beakers stolen from labs.

The video in the link has some slo-mo goodness, and explains that there are two categories of pyrex: consumer-grade and lab-grade. So the labware theft is not of vintage materials no longer available, possibly it occurs in order to avoid being tracked by actually purchasing it; there are fewer suppliers of lab-grade apparati than there are department stores selling the cheap stuff.

Taking this idea to the illogical extreme is Texas (surprise!), where it is illegal to buy/sell an Erlenmeyer flask (among other labware) without the proper paperwork, as it is considered an aid to making illegal chemicals. (I happen to own one, along with some beakers — they comprised my bar glassware back in the days when I had housemates and we threw parties; I could mix some pretty precise cocktails, and a 600 ml beaker is a good size for such drinks. The Erlenmeyer flask’s role was that of a wine decanter.) I wonder if this is a “shall-issue” permit. Regardless, it appears easier to get a handgun in Texas than lab glassware. Or Sudafed, since Pseudoephedrine is on the list as well, without mention of a threshold below which it’s not necessary to get a permit. I’d love to hear if anyone in the Lone Star State has applied to buy (or better yet, transfers/furnishes to someone else) a cold-remedy pill.