Archive for the ‘tidbits’ Category

Before its time?

September 2, 2011

The Avrocar located in Dayton, Ohio, US | Atlas Obscura | Curious and Wondrous Travel Destinations

In flight-testing, the Avrocar proved to have unresolved thrust and stability problems. The saucer proved immensely difficult to fly with very sensitive controls, and one pilot likened flying it to “balancing on a beach ball.” Though the Avrocar was made to fly up to 190 km/h and it was believed with some modifications the project was salvageable, funding ran out and the project was canceled in September 1961.

Nowadays, when any geek who can follow directions can build a four-rotor helicopter with cheap microcontrollers that adjust the attitude 30 times a second, it seems that all those designs for flying stuff that was dangerously unstable would now be a piece of cake. Of course, I could be wrong.

Yet another Tab Dump

August 9, 2011

Invasion of the Viking women unearthed – Science Fair – USATODAY.com

So, the study looked at 14 Viking burials from the era, definable by the Norse grave goods found with them and isotopes found in their bones that reveal their birthplace. The bones were sorted for telltale osteological signs of which gender they belonged to, rather than assuming that burial with a sword or knife denoted a male burial.

Overall, McLeod reports that six of the 14 burials were of women, seven were men, and one was indeterminable. Warlike grave goods may have misled earlier researchers about the gender of Viking invaders, the study suggests. At a mass burial site called Repton Woods, “(d)espite the remains of three swords being recovered from the site, all three burials that could be sexed osteologically were thought to be female, including one with a sword and shield,” says the study.

“These results, six female Norse migrants and seven male, should caution against assuming that the great majority of Norse migrants were male, despite the other forms of evidence suggesting the contrary. This result of almost a fifty-fifty ratio of Norse female migrants to Norse males is particularly significant when some of the problems with osteological sexing of skeletons are taken into account,”

Sun-free photovoltaics – MIT News Office

The solution, Celanovic says, is to design a thermal emitter that radiates only the wavelengths that the PV diode can absorb and convert into electricity, while suppressing other wavelengths. “But how do we find a material that has this magical property of emitting only at the wavelengths that we want?” asks Marin Soljačić, professor of physics and ISN researcher. The answer: Make a photonic crystal by taking a sample of material and create some nanoscale features on its surface — say, a regularly repeating pattern of holes or ridges — so light propagates through the sample in a dramatically different way.

“By choosing how we design the nanostructure, we can create materials that have novel optical properties,” Soljačić says. “This gives us the ability to control and manipulate the behavior of light.”

The team — which also includes Peter Bermel, research scientist in the Research Laboratory for Electronics (RLE); Peter Fisher, professor of physics; and Michael Ghebrebrhan, a postdoc in RLE — used a slab of tungsten, engineering billions of tiny pits on its surface. When the slab heats up, it generates bright light with an altered emission spectrum because each pit acts as a resonator, capable of giving off radiation at only certain wavelengths.

Silver pen has the write stuff for flexible electronics

While it looks like a typical silver-colored rollerball pen, this pen’s ink is a solution of real silver. After writing, the liquid in the ink dries to leave conductive silver pathways — in essence, paper-mounted wires. The ink maintains its conductivity through multiple bends and folds of the paper, enabling devices with great flexibility and conformability.

Metallic inks have been used in approaches using inkjet printers to fabricate electronic devices, but the pen offers freedom and flexibility to apply ink directly to paper or other rough surfaces instantly, at low cost and without programming

A certain naive charm

May 5, 2011

File-Sharers Await Official Recognition of New Religion | TorrentFreak

The church has its own set of axioms, most of which revolve around free access to knowledge and the sharing of information. They include:

# Reproduction of information is ethically right.
# The flow of information is ethically right.
# Remix Spirit is a sacred kind of copying.
# Copying or remixing information conveyed by another person is an act of respect.

Random robot gripping improvements tab dump

March 25, 2011

At some point we’re going to turn around and this kind of stuff will actually be useful, especially with improvements in vision so that machines can see the orientation of the things they’ve picked up.

DARPA fashions miracle robotic attachment from balloon, coffee • The Register

The manipulator works by pressing the soft balloon full of loose coffee grounds down on the object to be gripped. Then the air is sucked out of the balloon, causing the coffee granules to press together and lock into a rigid shape – just as they do when vacuum-packed. The object is now securely grasped by the manipulator, and can be released as desired by ending the suction on the granule-filled bulb.

Grip-Happy Compliant Electroadhesion Sneaking Into Everyday Usage

Today, they’ve moved onto bigger and better things, like gripping a banana using the same technique. Meet “compliant electroadhesion.”

As was the case back in 2008, electroadhesion still requires very little power to function. According to SRI, 11 square feet of electroadhesive material will support about 440-lbs. using 40mW.

This is why you test your new formulas first

March 24, 2011

The First Law of Development Stats: Whatever our Bizarre Methodology, We make Africa look Worse

The biggest change in method was that the new HDI is a geometric average rather than a normal (additive) average. Geometric average means you multiply the separate indices (each ranging between 0 and 1) for income, life expectancy, and education together and then take the cube root (I know your pulse starts to race here…)

Now, students, please notice the following: if one of these indices is zero, then the new HDI will be zero, regardless of how great the other indices are. The same mostly applies if one of the indices is close to zero. The new HDI has a “you’re only as strong as your weakest link” property, and in practice the weakest link turns out to be very low income (and guess which region has very low income).

You can see why the geometric average might have been attractive: by multiplying and then taking a root, it avoids the Bill-Gates-Walks-Into-A-Bar problem that besets arithmetic averages. But instead it makes errors in scaling or in linearity much worse. You gains on the swings, but you loses on the roundabouts.

And ultimately it’s always going to be about the scaling. $2 may make you twice as happy as $1, but $2 million is unlikely to make you twice as happy as $1 million, much less a million times as happy as $2.

It’s much, much easier, both mathematically and politically (because you get to avoid claims of subjectivity) to measure utility or development in linear terms of clear quantities like dollars or years of life or bushels of food. Too bad all you learn is ever more precisely where the house keys aren’t.

This is why you test your new formulas first

December 6, 2010

The First Law of Development Stats: Whatever our Bizarre Methodology, We make Africa look Worse

The biggest change in method was that the new HDI is a geometric average rather than a normal (additive) average. Geometric average means you multiply the separate indices (each ranging between 0 and 1) for income, life expectancy, and education together and then take the cube root (I know your pulse starts to race here…)

Now, students, please notice the following: if one of these indices is zero, then the new HDI will be zero, regardless of how great the other indices are. The same mostly applies if one of the indices is close to zero. The new HDI has a “you’re only as strong as your weakest link” property, and in practice the weakest link turns out to be very low income (and guess which region has very low income).

You can see why the geometric average might have been attractive: by multiplying and then taking a root, it avoids the Bill-Gates-Walks-Into-A-Bar problem that besets arithmetic averages. But instead it makes errors in scaling or in linearity much worse. You gains on the swings, but you loses on the roundabouts.

And ultimately it’s always going to be about the scaling. $2 may make you twice as happy as $1, but $2 million is unlikely to make you twice as happy as $1 million, much less a million times as happy as $2.

It’s much, much easier, both mathematically and politically (because you get to avoid claims of subjectivity) to measure utility or development in linear terms of clear quantities like dollars or years of life or bushels of food. Too bad all you learn is ever more precisely where the house keys aren’t.

Self-limiting Spam

November 9, 2010

From a message I got this morning:

How happy are you with your product documention?

Kids who want to learn will learn if you give them half a chance

November 4, 2010

Old but good

BBC News – Using computers to teach children with no teachers

“I told them: ‘there is some very difficult stuff on this computer, I won’t be surprised if you don’t understand anything’.”

Two months later, he returned.

Initially the children said they had not learnt anything, despite the fact that they used the computers everyday.

“Then a 12-year-old girl raised her hand and said ‘apart from the fact that improper replication of the DNA contributes to genetic disease – we’ve understood nothing else’.”

So the real question is more about getting more of them to want to learn the stuff that would be good for them to learn and getting anyone who might interfere with the process out of the way..

Is it geology or is it CGI

August 10, 2010

Giant Crystal Cave in the Mexican Desert | Amusing Planet

The giant obelisks are formed from groundwater saturated in calcium sulphate which filtered through the cave system millions of years ago. These water warmed by an intrusion of magma about a mile below, began filtering through the cave system millions of years ago. When, about 600,000 years ago, the magma began to cool, the minerals started to precipitate out of the water, and over the centuries the tiny crystals they formed grew and grew until 1985, when miners unwittingly drained the cave as they lowered the water table with mine pumps.

Some of the most amazing cave pictures

Not neat to be a neet?

August 1, 2010

BBC NEWS | UK | Education | Neets ‘should not get benefits’

MPs are suggesting adopting a system use in Holland reduce the number of 16 to 25-year-olds not in education, employment or training, known as Neets.

They said the Dutch equivalent of jobseeker’s allowance was dependent on being in work, education or training.

At the end of 2009, nearly 15% of 16 to 24-year-olds were classed as Neets.

And 9.3% of the youngsters classified as Neet at the end of 2009 were aged 16 to 18.

And the government looks set to miss its target to reduce that figure to an average of 7.6% for a whole of 2010.


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