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benjaminroussel

Magnet Finge.rs - 2 views

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    Bio-hacking/cyborg: implanting rare-earth magnets into your fingers to sense magnetic fields. At the same time quite awesome and quite extreme.
marliesarnhof

Evidence of a plume on Europa from Galileo magnetic and plasma wave signatures | Nature Astronomy - 1 views

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    Old data reveal new evidence of europa spouting plumes into space.
jaihobah

Topological insulator laser - 2 views

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    These are lasers whose lasing mode exhibits topologically-protected transport without magnetic fields. The underlying topological properties lead to a highly efficient laser, robust to defects and disorder, with single mode lasing even at very high gain values.
jcunha

Gravity hidden aspects of electrodynamics - 0 views

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    "Gravity spoils the symmetry regardless of whether magnetic monopoles exist or not. This is shocking. The bottom line is that the symmetry cannot exist in our universe at the fundamental level because gravity is everywhere"
jcunha

NASA proposes a magnetic shield to protect Mars' atmosphere - 2 views

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    In the Planetary Science Vision 2050 Workshop a cool concept for a magnetic dipole sitting at Mars L1 with an estimated field of 1-2 Tesla was proposed to shield Mars from Solar Winds and provide an elementary magnetic shielding to Mars.
fichbio

[1610.08323] Evidence for vacuum birefringence from the first optical polarimetry measurement of the isolated neutron star RX\, J1856.5$-$3754 - 3 views

shared by fichbio on 02 Dec 16 - No Cached
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    Abstract: The "Magnificent Seven" (M7) are a group of radio-quiet Isolated Neutron Stars (INSs) discovered in the soft X-rays through their purely thermal surface emission. Owing to the large inferred magnetic fields ($B\approx 10^{13}$ G), radiation from these sources is expected to be substantially polarised, independently on the mechanism actually responsible for the thermal emission.
jcunha

Synthetic Landau levels for photons - 1 views

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    Very nice experiment on the verge of Condensed matter Physics! The presence of Landau levels is a necessary condition to obtain a Quantum Hall state. Quantum Hall states have first appeared in 2D electronic gases when applied a perpendicular magnetic field that induces a new topological state of the "electronic gas". This new topological state is believed to "protect" some parameters of the system, such as conductance making it possible to measure fundamental constants with very high precision even in imperfect experimental conditions. In this fundamental experiment, a synthetic magnetic field was created that acts in continuum photons, producing "an integer quantum Hall system in curved space, a long-standing challenge in condensed matter physics".
jcunha

'Superman memory crystal' that could store 360TB of data forever | ExtremeTech - 0 views

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    A new so called 5D data storage that could potentially survive for billions of years. The research consists of nanostructured glass that can record digital data in five dimensions using femtosecond laser writing.
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    Very scarce scientific info available.. I'm very curious to see a bit more in future. From https://spie.org/PWL/conferencedetails/laser-micro-nanoprocessing I made a back of envelop calc: for 20 nm spaced, each laser spot in 5D encryption encodes 3 bits (it seemed to me) written in 3 planes, to obtain the claimed 360TB disk one needs very roughly 6000mm2, which does not complain with the dimensions shown in video. Only with larger number of planes (order of magnitude higher) it could be.. Also, at current commercial trends NAND Flash and HDD allow for 1000 Gb/in2. This means a 360 TB could hypothetically fit in 1800mm2.
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    I had the same issue with the numbers when I saw the announcement a few days back (https://www.southampton.ac.uk/news/2016/02/5d-data-storage-update.page). It doesn't seem to add up. Plus, the examples they show are super low amounts of data (the bible probably fits on a few 1.44 MB floppy disk). As for the comparison with NAND and HDD, I think the main argument for their crystal is that it is supposedly more durable. HDDs are chronically bad at long term storage, and also NAND as far as I know needs to be refreshed frequently.
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    Yes Alex, indeed, the durability is the point I think they highlight and focus on (besides the fact the abstract says something as the extrapolated decay time being comparable to the age of the Universe..). Indeed memories face problems with retention time. Most of the disks retain the information up to 10 years. When enterprises want to store data for longer times than this they use... yeah, magnetic tapes :-). Check a interesting article about magnetic tape market revival here http://www.information-age.com/technology/data-centre-and-it-infrastructure/123458854/rise-fall-and-re-rise-magnetic-tape I compared for fun, to have one idea of what we were talking about. I am also very curious so see the writing and reading times in this new memory :)
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    But how can glass store the information so long? Glass is not even solid?!
LeopoldS

Steel Treatment Paves the Way For Radically Lighter, Stronger, Cheaper Cars - Slashdot - 2 views

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    my old question: how could we use it for space?
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    It will depend on the alloys used, I am not sure but bainite might magnetic and I am not sure if nickel alloy based (stainless) steels can be processed at this low temperature... Metallurgist RF?
Nina Nadine Ridder

Microscopic fish are 3-D-printed to do more than swim: Researchers demonstrate a novel method to build microscopic robots with complex shapes and functionalities - 1 views

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    Useful for space exploration, e.g. subsurface water reservoirs such as Europa or Enceladus? Nanoengineers at the University of California, San Diego used an innovative 3-D printing technology they developed to manufacture multipurpose fish-shaped microrobots -- called microfish -- that swim around efficiently in liquids, are chemically powered by hydrogen peroxide and magnetically controlled.
Thijs Versloot

Student Confirms That There Are Enormous Tubes Of Plasma Floating Above The Earth - 1 views

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    A 60-year-old theory about the structure of the magnetic fields that surround Earth has been confirmed directly for the first time. The lead author of the paper is an undergraduate student who invented a way to view the Earth's magnetosphere in three dimensions.
jcunha

Missing link in metal physics explains Earth's magnetic field - 0 views

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    In a work published on Nature (http://www.nature.com/nature/journal/v517/n7536/full/nature14090.html#affil-auth) a new DFT based simulation of convection in Earth's Core iron shows that electron-electron scattering has a similar contribution to electron's thermal vibration. The outcome is that using the old dynamo theory the simulation matches the Earth magnetic field experimental results, solving an 80 years old puzzle.
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    Yay to science! I'm always intrigued by related experiments that try to measure material properties at the GPa range. Especially, the efforts of reaching 'metallic hydrogen' (http://en.wikipedia.org/wiki/Metallic_hydrogen), requiring pressures above 25GPa at which hydrogen becomes conductive. It is thought that gas giant planets could have such a core, but no-one has been able to produce/verify this theory as off yet.
johannessimon81

Practical Electrostatic Motor(?) - 3 views

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    Apparently a spin-off company of the University of Wisconsin is developing non-magnetic motors. Maybe this could be useful for reaction wheels etc. on satellites that monitor the Earth's magnetic field... (preventing magnetic interference with sensors)
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    Duncan, this is one for you! - you can probably even build one in your kitchen ...
Tom Gheysens

Direct brain-to-brain communication demonstrated in human subjects -- ScienceDaily - 2 views

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    In a first-of-its-kind study, an international team of neuroscientists and robotics engineers has demonstrated the viability of direct brain-to-brain communication in humans.
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    Was just about to post it... :) It seems after transferring the EEG signals of one person, converting it to bits and stimulating some brain activity using magnetic stimulation (TMS) the receiving person actually sees 'flashes of light' in their peripheral vision. So its using your vision sense to get the information across. Would it not be better to try to see if you can generate some kind of signal in the part of your brain that is connected to 'hearing'? Or would this be me thinking too naive?
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    "transferring the EEG signals of one person, converting it to bits and stimulating some brain activity using magnetic stimulation (TMS)" How is this "direct"?
Thijs Versloot

Magnetic bubble may give space probes a soft landing - 4 views

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    I am also looking into this idea since some time and it seems NASA is already ahead, awarding two contract to investigate magnetoshell aerocapture. This could be interesting for probes that want to enter eg Marsian atmospheres at relatively high velocity. Or for multiple re-entry s/c at Earth. The idea of the experiment, The satellite will carry a copper coil, powered by a lithium-ion battery, that generates a magnetic field around the probe. As it descends, the spacecraft will eject a small amount of plasma. This gets trapped in the magnetic field, creating a protective bubble that stops air molecules colliding with the craft and producing heat.
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    A few years back Mimmo has worked on this, rather from the theory side if I remember well ...
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    The power requirements for such a thing must be HUGE!
Christophe Praz

Small cube robots that self-assemble - 3 views

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    Using the angular momentum transmitted by an internal flywheel as an impulse, these cubes can move, jump, roll across the ground and climb over and around one another. They stick together using a set of small magnets, smart !
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    That is indeed a great way of using modular robots to build larger structures. I think we did bump into this some time back, but never really considered it much. Considering now the working group on structure assembling, I think we should add it to the list of building strategies and seriously consider it.
Thijs Versloot

Relativistic rocket: Dream and reality - 3 views

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    An exhaustive overview of all possible advanced rocket concepts, eg.. "As an example, consider a photon rocket with its launching mass, say, 1000 ton moving with a constant acceleration a =0.1 g=0.98 m/s2. The flux of photons with E γ=0.5 MeV needed to produce this acceleration is ~1027/s, which corresponds to the efflux power of 1014 W and the rate of annihilation events N'a~5×1026 s−1 [47]. This annihilation rate in ambiplasma l -l ann corresponds to the value of current ~108 A and linear density N ~2×1018 m−1 thus any hope for non-relativistic relative velocity of electrons and positrons in ambiplasma is groundless." And also, even if it would work, then one of the major issues is going to be heat dispersal: "For example, if the temperature of radiator is chosen T=1500 K, the emitting area should be not less than 1000 m2 for Pb=1 GW, not less than 1 km2 for Pb=1 TW, and ~100 km2 for Pb=100 TW, assuming ε=0.5 and δ=0.2. Lower temperature would require even larger radiator area to maintain the outer temperature of the engine section stable for a given thermal power of the reactor."
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    We were also discussing a while ago a propulsion system using the relativistic fragments from nuclear fission. That would also produce an extremely high ISP (>100000) with a fairly high thrust. Never really got any traction though.
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    I absolutely do not see the point in a photon rocket. Certainly, the high energy releasing nulcear processes (annihilation, fusion, ...) should rather be used to heat up some fluid to plasma state and accelerate it via magnetic nozzle. This would surely work as door-opener to our solar system...and by the way minimize the heat disposal problem if regenerative cooling is used.
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    The problem is not achieving a high energy density, that we can already do with nuclear fission, the question however is how to confine or harness this power with relatively high efficiency, low waste heat and at not too crazy specific mass. I see magnetic confinement as a possibility, yet still decades away and also an all-or-nothing method as we cannot easily scale this up from a test experiment to a full-scale system. It might be possible to extract power from such a plasma, but definitely well below breakeven so an additional power supply is needed. The fission fragments circumvent these issues by a more brute force approach, thereby wasting a lot of energy for sure but at the end probably providing more ISP and thrust.
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    Sure. However, the annihilation based photon rocket concept unifies almost all relevant drawbacks if we speak about solar system scales, making itself obsolete...it is just an academic testcase.
Marcus Maertens

Physicists create synthetic magnetic monopole predicted more than 80 years ago - 1 views

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    Hall's team adopted an innovative approach to investigating Dirac's theory, creating and identifying synthetic magnetic monopoles in an artificial magnetic field generated by a Bose-Einstein condensate, an extremely cold atomic gas tens of billionths of a degree warmer than absolute zero.
Beniamino Abis

Antimatter experiment produces first beam of antihydrogen - 1 views

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    The ASACUSA experiment at CERN has succeeded for the first time in producing a beam of antihydrogen atoms. The ASACUSA collaboration reports the unambiguous detection of 80 antihydrogen atoms 2.7 metres downstream of their production, where the perturbing influence of the magnetic fields used initially to produce the antiatoms is small. http://www.nature.com/ncomms/2014/140121/ncomms4089/full/ncomms4089.html
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