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santecarloni

Seismic Metamaterials Could Cloak Dams and Power Stations  - Technology Review - 2 views

www.technologyreview.com/...27566

metamaterial phy

shared by santecarloni on 17 Feb 12 - No Cached
  • santecarloni on 17 Feb 12
     
    Metamaterials that absorb seismic waves rather than steer them, might be a better way to protect some buildings, say engineers
  • ...1 more comment...
  • Luzi Bergamin on 18 Feb 12
     
    ???
  • LeopoldS on 21 Feb 12
     
    what are seismic metamaterials?
  • LeopoldS on 21 Feb 12
     
    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).
santecarloni

Artificial Braneworlds Made to Collide In Lab - Technology Review - 4 views

www.technologyreview.com/...27537

metamaterials cosmology PHY

shared by santecarloni on 31 Jan 12 - No Cached
pacome delva liked it
  • santecarloni on 31 Jan 12
     
    Physicists have simulated two universes colliding inside a metamaterial--  Now, this is cool (if it is true...)
  • ...1 more comment...
  • LeopoldS on 01 Feb 12
     
    we... the article is a bit overblown in my view ... except maybe the last paragraphs: "The collision between universe's is a variation on this theme. "The "colliding universe" scenario can be realized as a simple extension of our earlier experiments simulating the spacetime geometry in the vicinity of big bang," he says. He simulates an expanding universe using concetric rings of gold separated by a dielectric. "When the two concentric ring ("universe") patterns touch each other ("collide"), a Minkowski domain wall is created, in which the metallic stripes touch each other at a small angle," he says. Being able to recreate these exotic events in the lab is certainly interesting but it is beginning to lose its novelty. The problem is that this work is not telling us anything we didn't know--the universe behaves the same way inside a metamaterial as it does outside. What Smolyaninov needs is a way of using his exotic materials to do something interesting. In other words, he needs a killer app. Any ideas? "
  • Luzi Bergamin on 05 Feb 12
     
    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
  • LeopoldS on 10 Feb 12
     
    Luzi I miss you ...
johannessimon81

Fractals vs. Superconductors vs. Black Holes - 2 views

www.wired.com/...superconductor-fractals

science technology

shared by johannessimon81 on 04 Dec 13 - No Cached
  • johannessimon81 on 04 Dec 13
     
    Nice wired article on high temp. superconductors. With some quotes by my old material science Prof. Jan Zaanen :-D
Athanasia Nikolaou

Swarm behaviour modified by air/sea turbulence. - 2 views

phys.org/...015-05-flocking-behaviour.html

turbulence swarm phytoplankton EarthObservation fluid MATH

shared by Athanasia Nikolaou on 26 May 15 - No Cached
  • Athanasia Nikolaou on 26 May 15
     
    Seems looking into turbulence is a source of innovative concepts. After the black hole modelling here was found a mathematical expression which describes "how turbulence can alter the shape and course of a flock of birds, a swarm of insects or even an algal bloom (phytoplankton!) and could help us to better predict them". More relevant for motions in air and sea, rather than space, where the fluids are dense enough to exhibit turbulence ; but what about a swarm moving in and exploring an exoplanet's atmosphere?
pacome delva

Radiation fears stalk stellar mission - 0 views

physicsworld.com/...43063

space_mission GAIA solar_radiation

shared by pacome delva on 05 Jul 10 - Cached
  • Concern over ESA's handling of the radiation issue caused Michael Perryman, former GAIA project scientist, to resign from the agency in 2008. But GAIA science-team member Lennart Lindegren, an astronomer at Lund Observatory in Sweden, is confident that GAIA's unprecedented accuracy will be feasible. GAIA researchers will continue to perform tests and calibrations until at least 2011, which will include irradiating the CCDs at space-like temperatures. Lindegren admits, however, that they can never be certain of success until the spacecraft is in orbit and starts sending back data.
  • pacome delva on 05 Jul 10
     
    metamaterials to stop radiations?
  • LeopoldS on 05 Jul 10
     
    hmm ... in the optical range it is already a bit tricky .... lets brainstorm a bit about it ... anything in the literature? Luzi?
  • pacome delva on 06 Jul 10
     
    the components of the metamaterial need to have a size inversely proportional to the wavelenght, but here we are talking about high energy protons. So the idea was: is there metamaterials that change the electrical properties to solve this problem of holes in the material... but i dont have a clue !
LeopoldS

NASA - NASA's Fermi Telescope Finds Giant Structure in our Galaxy - 5 views

www.nasa.gov/...new-structure.html

space phy astronomy

shared by LeopoldS on 15 Nov 10 - No Cached
  • LeopoldS on 15 Nov 10
     
    wow ....
  • ...1 more comment...
  • Ma Ru on 15 Nov 10
     
    I guess that's the "exceptional object in our cosmic neighbourhood"...
  • pacome delva on 15 Nov 10
     
    impressive! I'm sure it's connected to the black hole, at some point it must have been active. It shows how it's important to put all observations public !
  • LeopoldS on 16 Nov 10
     
    this is what they speculate ... the original image looks though much less impressive ...
pacome delva

Penrose claims to have glimpsed universe before Big Bang - 0 views

physicsworld.com/...44388

phy cosmology

shared by pacome delva on 22 Nov 10 - No Cached
LeopoldS liked it
  • According to Penrose and Gurzadyan, these circles allow us to "see through" the Big Bang into the aeon that would have existed beforehand. The circles, they say, are the marks left in our aeon by the spherical ripples of gravitational waves that were generated when black holes collided in the previous aeon.
  • Julian Barbour, a visiting professor of physics at the University of Oxford, says that these circles would be "remarkable if real and sensational if they confirm Penrose's theory". They would, he says, "overthrow the standard inflationary picture", which, he adds, has become widely accepted as scientific fact by many cosmologists. But he believes that the result will be "very controversial" and that other researchers will look at the data very critically. He says there are many disputable aspects to the theory
  • pacome delva on 22 Nov 10
     
    hehe, a nice controversy? or completely overinterpreted results...?
  • LeopoldS on 23 Nov 10
     
    what the heck is this? sounds strange to me ... would I understand the original paper?
Luzi Bergamin

Physics in a Crisis - 3 views

www.rqm.ch/physics_in_a_crisis.htm

phy LHC crackpot fun

shared by Luzi Bergamin on 30 Mar 10 - Cached
  • Luzi Bergamin on 30 Mar 10
     
    Luckily I'm far away from Geneva, but this has to be said today, when the LHC starts! No, not tiny black holes will eat us (what a nonsense!), but the supernovae energy will let LHC explode!!! Pacome, I expect you to debunk this with gratest care!
  • ...2 more comments...
  • pacome delva on 30 Mar 10
     
    wtf is this! As I read this morning in the newspaper (not even a scientific one), 1 TeV is the kinetic energy of a flying mosquito... so be careful ! It seems they already sloved every thing on this website: "At the Institute for Space Quantum Physics ISQP, it was already proved in 1991-1992 that dark matter is in magnetic fields as magnetic space quantum flux." This website is the biggest source of crackpots i have seen in a long time...! (http://www.supernovae-energy.com/)
  • Ma Ru on 30 Mar 10
     
    Come on guys, this website is hilarious! "The HAITI EARTHQUAKE (...) were impossible for the Institute for Space Quantum Physics (ISQP) to compute because on one single planet was on a common line or axis with the Sun: Venus."
  • Luzi Bergamin on 30 Mar 10
     
    Unfortunately, most information I have about the guy (Hans Lehner, a Swiss) is in German, his official homepage is http://www.rqm.ch/ According to EsoWatch he is the Swiss analogue to Dr. Mills and his Blacklight power. Lehner apparently founded a company, which should have produced a "Raum-Quanten-Motor" that -- of course -- produces energy out of nothing. The theory is based on spookey forces mediated by Lehneronen. 11 Million Swiss Franks (about 8 Million Euro) were lost when the company bankrupt. And the guy is selling new stocks on his homepage again... Lehner calls another crackpot named Oliver Crane Zweistein (from Einstein being "Onestone") and himself "Dreistein". Now he is looking for Mister or Misses Vierstein. Perhaps you should apply, good luck!!
  • Nicholas Lan on 30 Mar 10
     
    i like the first line of their supernovae energy technology document "Dear potential investor:"...
Ma Ru

LHC 7TeV experiment webcast, TODAY 9:00-11:00 - 1 views

webcast.cern.ch/lhcfirstphysics

phy web science

shared by Ma Ru on 30 Mar 10 - Cached
  • Ma Ru on 30 Mar 10
     
    Watch the Earth vanish in a back hole again.
Luís F. Simões

SETI, Citrus Division - 1 views

www.newscientist.com/...cted-at-kinetica-art-fair.html

SETI fun

shared by Luís F. Simões on 07 Feb 11 - No Cached
  • A nice contrast to these high-tech installations, Adrian Lee's Search for Extra-Terrestrial Intelligence (SETI) Citrus Division (below), sees 65 lemons trying to communicate with aliens. Using their own juices, these lemon batteries power a small motor - which turns a disc into which is punched the Morse code for "We are here". As the disc rotates, a class 2 laser - also powered by the lemons - shines through the holes and the encoded message is then directed by a small mirror up into space...or in this case, onto the ceiling of the Ambica P3 venue. Amusing, simple and sophisticated all at once, the Citrus Division mixes old and new science and technology in just the right measure.
pacome delva

Spinning black holes twist light - 1 views

physicsworld.com/...45104

general_relativity black_holes electromagnetism

shared by pacome delva on 16 Feb 11 - No Cached
Nicholas Lan liked it
  • pacome delva on 16 Feb 11
     
    so coool ! an application for the rototenna :)
Ma Ru

Phineas Gage - 3 views

www.bbc.co.uk/...health-12649555

neuroscience science

shared by Ma Ru on 06 Mar 11 - No Cached
  • Ma Ru on 06 Mar 11
     
    As I now work in the Centre for Robotics *and Neuroscience*, here's a story for you. Some highlights: "It sent the iron straight up into his skull and out of the top of his head, landing some 30 metres away. (...) Phineas was unconscious before getting up and riding an oxcart into town with, 'a big bleedin' hole in his head'. (...) although Phineas survived, he was a changed man. Now he was reportedly unreliable, partial to swearing and often making inappropriate remarks." I guess If I were him I'd be a little partial to swearing too.
  • ...1 more comment...
  • LeopoldS on 07 Mar 11
     
    what sort of story is this please???
  • Ma Ru on 07 Mar 11
     
    Apparently you didn't read it... This is a story about how science is born :)
  • LeopoldS on 07 Mar 11
     
    now I did ... :-) just had read your comment ....
Francesco Biscani

Asteroid blast reveals holes in Earth's defences - space - 26 October 2009 - New Scientist - 2 views

www.newscientist.com/...dn18046

asteroid

shared by Francesco Biscani on 28 Oct 09 - Cached
  • On 8 October an asteroid detonated high in the atmosphere above South Sulawesi, Indonesia, releasing about as much energy as 50,000 tons of TNT, according to a NASA estimate released on Friday. That's about three times more powerful than the atomic bomb that levelled Hiroshima, making it one of the largest asteroid explosions ever observed.
Francesco Biscani

Found: first 'skylight' on the moon - space - 22 October 2009 - New Scientist - 2 views

www.newscientist.com/...irst-skylight-on-the-moon.html

moon

shared by Francesco Biscani on 28 Oct 09 - Cached
pacome delva liked it
  • A deep hole on the moon that could open into a vast underground tunnel has been found for the first time. The discovery strengthens evidence for subsurface, lava-carved channels that could shield future human colonists from space radiation and other hazards.
Ma Ru

Dark Matter or Black Hole Propulsion? - 1 views

www.newscientist.com/...s-for-interstellar-travel.html

NRG propulsion star travel space PHY

shared by Ma Ru on 25 Nov 09 - Cached
  • Ma Ru on 25 Nov 09
     
    Anyone out there still doing propulsion stuff? Two more papers just waiting to get busted... http://arxiv.org/abs/0908.1429v1 http://arxiv.org/abs/0908.1803
  • ...5 more comments...
  • Luzi Bergamin on 26 Nov 09
     
    What an awful bunch of complete nonsense!!! But I don't think anybody wants to hear MY opinion on this...
  • pacome delva on 26 Nov 09
     
    wow, is this serious at all...!?
  • Luzi Bergamin on 26 Nov 09
     
    Are you joking?? The BH drive propses a BH with a lifetime of about an year, just 10^7 tons, peanuts!! Then you have to produce it, better not on Earth, so you do this in space, with a laser that produces an equivalent of 10^9 tons highly foucussed, even more peanuts!! Reasonable losses in the production process (probably 99,999%) are not yet taken into account. Engineering problems... :-) The DM drive is even better, they want to collect DM and compress it in a propulsion chamber. Very easy to collect and compress a gas of particles that traverse the Earth without any interaction. Perhaps if the walls of the chamber are made of artificial BHs?? Who knows??
  • LeopoldS on 26 Nov 09
     
    WRONG!!! we are all just WAITING for your opinion on this ....!!!
  • pacome delva on 27 Nov 09
     
    well, yes my remark was ironic... I'm surprised they did a magazine on these concepts...! But the press is always waiting for sensational. They do not even wait for the work to be peer-reviewed now to make an article on it ! This is one of the bad sides of arxiv in my opinion. It's like a journalist that make an article with a copy-paste in wikipedia ! Anyway, this is of course complete bullsh..., and I would have laughed if I had read this in a sci-fi book... but in a "serious" article i'm crying... For the DM i do not agree with your remark Luzi. It's not dark energy they want to use. The DM is baryonic, it's dark just because it's cold so we don't see it by usual means. If you believe the in the standard model of cosmology, then the DM should be somewhere around the galaxies. But it's of course not uniformly distributed, so a DM engine would work (if at all...) only in the periphery of galaxies. It's already impossible to get there...
  • Luzi Bergamin on 27 Nov 09
     
    One reply to Pacome, though the discussion exceeds by far the relevance of the topic already. Baryonic DM is strictly limited by cosomology, if one believes in these models, of course. Anyway, even though most DM is cold, we are constantly bombarded by some DM particles that come together with cosmic radiation, solar wind etc. etc. If DM easily interacted with normal matter, we would have found it long ago. In the paper they consider DM as neutralinos, which are neither baryonic nor strongly or electromagnetically interacting.
  • pacome delva on 27 Nov 09
     
    well then I agree, how the fu.. they want to collect them !!!
Luís F. Simões

Following SpaceX down the rabbit hole -- The Space Review - 4 views

www.thespacereview.com/...1

SpaceX launcher

shared by Luís F. Simões on 19 Apr 11 - No Cached
  • He then went on to remind the press that his company’s goal is to continue to lower the cost of access to space because high launch costs were “the fundamental factor preventing humanity from becoming a spacefaring civilization.”
  • First, two Falcon Heavy launches could field a return to the Moon
  • Second, a single Falcon Heavy could launch a Mars sample return mission.
  • ...3 more annotations...
  • Also possible with a single launch: a first ever human mission to an asteroid.
  • what effect Falcon Heavy might have on the costs of supporting the International Space Station. The ability to launch twice the supply capacity provided by the shuttle at something on the order of 20 percent of the cost changes the calculus entirely. So much so in fact, it opens the door for contemplating an entirely different future for ISS in which it never follows Mir into the Pacific.
  • Following conclusions offered by the Augustine Committee, the Obama Administration cancelled Project Constellation as unaffordable under existing budget limits, and supported instead the ambling, but cost-contained “flexible path.” If the Falcon Heavy is available, however, the rationale for selecting the flexible path—because it’s the only thing we can afford—simply doesn’t exist.
  • Luís F. Simões on 19 Apr 11
     
    an analysis of implications of the Falcon Heavy announcement
santecarloni

Aircraft punch holes in clouds and make it rain - physicsworld.com - 2 views

physicsworld.com/...46388

rain PHY science

shared by santecarloni on 01 Jul 11 - No Cached
  • santecarloni on 01 Jul 11
     
    Altering local weather?
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