Group items tagged

Deepest X-ray Image Ever Reveals Black Hole Treasure Trove An unparalleled image from NASA's Chandra X-ray Observatory gives astronomers the best look yet at the growth of black holes over billions of years beginning soon after the Big Bang.

Metamaterials that absorb seismic waves rather than steer them, might be a better way to protect some buildings, say engineers

what are seismic metamaterials?

must look funny ... They calculate the properties of such a metatmaterial and how it might be constructed with a basic repeating unit in the form of a concrete cylinder some 18 metres in diameter, with four perpendicular holes in its sides (see picture). These cylinders, perhaps varying in size to absorb a range of seismic wavelengths, would need to surround the foundations of a building in cylindrical shells some 60 metres across. That needn't be prohibitively expensive but it would be a big structure that could only be constructed around isolated buildings (thereby somewhat negating the supposed benefit that other buildings in the earthquake 'shadow' might also be protected).

Will this work?

It can work...if it is privately funded. Technically it is not a big deal anymore.

from Andrés (don't ask my why he is not putting it directly on diigo ....) quite an old issue, though still of high actuality ... and a nice summary in my view ...

amusing take on innovation A tiny number of ideas can go a long way, as we've seen. And the Internet makes that more and more likely. What's happening is that we might, in fact, be at a time in our history where we're being domesticated by these great big societal things, such as Facebook and the Internet. We're being domesticated by them, because fewer and fewer and fewer of us have to be innovators to get by. And so, in the cold calculus of evolution by natural selection, at no greater time in history than ever before, copiers are probably doing better than innovators. Because innovation is extraordinarily hard. My worry is that we could be moving in that direction, towards becoming more and more sort of docile copiers.

Physicists have simulated two universes colliding inside a metamaterial--  Now, this is cool (if it is true...)

Hm, they use more or less everything I don't especially like. They are nonmagnetic, so the relation materialGR is already rather weak. Usually, experimentalists prefer nonmagnetic media, since they are cheaper and broadband. At least the broadband is no argument here, since the frequency defines the "mass", which I find a rather strange point of view. And finally, they use strong anisotropy as a model of "time", which is rather problematic. Of course, the spatial direction with eps<0 appears in the wave equation with the same sign as time. But this does not mean that it behaves like time. But to teach material physicists that time is more than just a different sign in the wave equation seems to be as hopeless as to teach them that a black hole is more than something that absorbs all light... SIGHHH

Luzi I miss you ...

Thijs interested? quinones are my field

I think the major benefit of this system is the low cost of the products involved compared to standard flow batteries. However, two issues still remain, corrosion and size. I think these things need to be big right due to the volumetric storage using quinones? Nevertheless, it is interesting to see where this development will lead to. "The system is far from perfect, however: bromine and hydrobromic acid are corrosive, and could cause serious pollution if they leaked. "The bromine is, right now, the Achilles heel of this particular battery," Aziz says. The answer could be to go completely organic, he adds: "We are working on replacing the bromine with a different quinone." Are there quinones which would not be corrosive but retain good volumetric performance?

That is about € 14e9 - enough to pay more than a million YGTs for half a year. Could we use maybe just half a million YGTs for half a year to build a similar platform and keep the remaining € 7e9 for ourselves? Keep in mind that WhatsApp only has 45 employees (according to AllThingsD: http://goo.gl/NtJcSj ). So we would have an advantage > 10000:1. On the other hand does this mean that every employee at WhatsApp gets enough money now to survive comfortably for ~5000 years or will the inevitable social inequality strike and most people get next to nothing while a few get money to live comfortably for ~1000000 years? Also: Does Facebook think about these numbers before they pay them? Or is it just a case of "That looks tasty - lets have it"? Also (2): As far as I can see all these internet companies (Google, Facebook, Yahoo, WhatsApp, Twitter...) seem to make most of their income from advertising. For all these companies together that must be a lot of advertising money (turns out that in 2013 the world spent about $ 500 billion on advertising: http://goo.gl/vYog15 ). For that money you could of course have 20 million YGTs roaming the Earth and advertising stuff door-to-door... ... ...

The whole valuation of those internet companies is a bit scary. Things like the Facebook and Twitter ipo numbers seem just ridiculous.

Facebook is not really so much buying into a potential good business deal as much as it's buying out risky competition. Popular trends need to be killed fast before they take off the ground too much. Also the amount of personal data that WhatsApp is amassing is staggering. I have never seen an app requesting so many phone rights in my life.

Thermoelectric materials can see their performance radically improved via the utilization of an array of 'nanoscale pillars,' according to new research from the University of Colorado Boulder. These tiny pillars, built directly onto the thermoelectric material, will reduce the heat flow through the material by a factor of two while not affecting the electrical flow.

Quote: "This is exactly what we are pursuing - self-assembling materials that organize at smaller sizes, say, less than 20 or even 10 nanometers"

Direct Self-Assembly (DSA) is one of the competitors for the next-generation 'lithography' together with direct-write via electron beam and the more traditional extreme UV (EUV) lithography. Although there are huge benefits to use DSA, the technology does have some drawbacks when it comes to line edge roughness. It seems however particularly good for repetitive structures that are used in memory chips. As long as EUV is struggling to get it working, DSA definitely has a fighting chance to enter the market one day.

Very interesting advances in materials

The underground lake is big enough to cover Kenia's water need for the next 70 years

Big Bang was mirage from collapsing higher-dimensional star, theorists propose.

Some sort of organic carbon has been detected by the sampling of Curiosity; the contamination source was isolated and the signal persists. The scientists suggest as a source meteorites transporting interstellar matter, or maybe some sort of ancient life whose biomass production only survived cosmic radiation as it was buried underground. a big deal: six relevant articles were published simultaneously online: http://www.sciencemag.org/site/extra/curiosity/index.xhtml?utm_content=&amp;utm_medium=Facebook&amp;utm_campaign=Science&amp;utm_source=shortener

We thought about a modular SAT concept in tahe past (looking to the second issue of Acta Futura its already there) .... but never made concrete steps ....

Interesting insight indeed, I see quite some overlap with the ACT mantra, athough they have 250 people and an outdoor playground.. To Teller, this failure-loving lab has simply stepped into the breach. Small companies don't feel they have the resources to take moonshots. Big companies think it'll rattle shareholders. Government leaders believe there's not enough money, or that Congress will characterize a misstep or failure as a scandal. These days, when it comes to Hail Mary innovation, "Everyone thinks it's somebody's else's job," Teller says.

What is the best (wisest) size for a group of individuals? Couzin and Kao put together a series of mathematical models that included correlation and several cues. In one model, for example, a group of animals had to choose between two options-think of two places to find food. But the cues for each choice were not equally reliable, nor were they equally correlated. The scientists found that in these models, a group was more likely to choose the superior option than an individual. Common experience will make us expect that the bigger the group got, the wiser it would become. But they found something very different. Small groups did better than individuals. But bigger groups did not do better than small groups. In fact, they did worse. A group of 5 to 20 individuals made better decisions than an infinitely large crowd. The problem with big groups is this: a faction of the group will follow correlated cues-in other words, the cues that look the same to many individuals. If a correlated cue is misleading, it may cause the whole faction to cast the wrong vote. Couzin and Kao found that this faction can drown out the diversity of information coming from the uncorrelated cue. And this problem only gets worse as the group gets bigger.

Couzin research was the starting point that co-inspired PaGMO from the very beginning. We invited him (and he came) at a formation flying conference for a plenary here in ESTEC. You can see PaGMO as a collective problem solving simulation. In that respect, we learned already that the size of the group and its internal structure (topology) counts and cannot be too large or too random. One of the project the ACT is running (and currently seeking for new ideas/actors) is briefly described here (http://esa.github.io/pygmo/examples/example2.html) and attempts answering the question :"How is collective decision making influenced by the information flow through the group?" by looking at complex simulations of large 'archipelagos'.

ooops ....

Where is the sticker saying "if found, please post this item unstamped to the following address"?

Yup, it's ours... Still, better take it out of the river than in the face. Such a big one especially.

A nice article explaining the principle of quantum superposition from the double slits experience. Nothing new here but still interesting to read :)

I myself am quite a big fan of the one-electron universe paradigm :))) And of the cat cannon: http://www.askamathematician.com/2010/12/q-can-you-do-the-double-slit-experiment-with-a-cat-cannon/