Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?

Submission Summary: 0 pending, 34 declined, 7 accepted (41 total, 17.07% accepted)

Slashdot videos: Now with more Slashdot!

  • View

  • Discuss

  • Share

We've improved Slashdot's video section; now you can view our video interviews, product close-ups and site visits with all the usual Slashdot options to comment, share, etc. No more walled garden! It's a work in progress -- we hope you'll check it out (Learn more about the recent updates).


+ - Time to "get knotted"->

Submitted by LeadSongDog
LeadSongDog (1120683) writes "In a long-sought analysis in Phys Lett B, Itzhak Bars and Dmitry Rychkov have shown that the basic assumptions that underly Quantum Mechanics can actually be derived from M-theoretic explanations of string interactions. It all comes down to some rules on how strings are joined and split.
For those who just want the simple version: http://www.futurity.org/string..."

Link to Original Source

+ - Ask Slashdot: Carbyne Suited For Space Elevator Cable?->

Submitted by LeadSongDog
LeadSongDog (1120683) writes "Somebody check my numbers, this sounds too good to be true... A new ACS paper on the theoretical structure of carbyne gives its breaking strength at 10nN for a single atomic chain of carbon. A single C12 atom weighs (at 1g) 2e-25 N, so the chain could support 5e24 atoms at that acceleration. If the atoms repeat 17 times for every 2.2 nm along the chain, the self-supporting chain could be 6e14 m long. This seems to be way longer than the space elevator would need, so I'm inclined to think I've missed something basic. What am I overlooking?"
Link to Original Source

+ - DC Light Now Available->

Submitted by LeadSongDog
LeadSongDog (1120683) writes "The headline writers at PhysOrg report "New material gives visible light an infinite wavelength". Of course the details within are rather less spectacular: "Researchers from the FOM Institute AMOLF and the University of Pennsylvania have fabricated a material which gives visible light a nearly infinite wavelength". The original work uses language that makes clear they are speaking of the phase velocity of visible light, under the title "Experimental realization of an epsilon-near-zero metamaterial at visible wavelengths". Still, it's an interesting read. http://www.nature.com/nphoton/journal/vaop/ncurrent/full/nphoton.2013.256.html"
Link to Original Source

+ - City-sized ice shelf breaks free->

Submitted by LeadSongDog
LeadSongDog (1120683) writes "Germany's TerraSAR-X satellite is showing that the Antarctic's Pine Island ice shelf has calved a 'berg of 720 square kilometres, "the size of Hamburg".

Angelika Humbert says "The Western Antarctic land ice is on land which is deeper than sea level. Its "bed" tends towards the land. The danger therefore exists that these large ice masses will become unstable and will start to slide". The article extrapolates that "If the entire West Antarctic ice shield were to flow into the Ocean, this would lead to a global rise in sea level of around 3.3 metres."

Goodbye Florida.

Link to Original Source

+ - Knotted flaky graphene oxide fibers are not weakened->

Submitted by LeadSongDog
LeadSongDog (1120683) writes "James Tour, in Advanced Materials, advises that his team has learned how to knot and weave graphene oxide fiber without losing strength. By mixing in large flakes, it keeps its bend radius relatively large at the knots. The resultant product reaches a 47GPa tensile modulus, just as strong as the native fiber. So, can this lesson be applied to carbon nanotubes, to fulfill Arthur C. Clarke's vision of a space elevator?

The full paper is at http://onlinelibrary.wiley.com/doi/10.1002/adma.201301065/abstract"

Link to Original Source

+ - It's the kablooie that keeps on giving->

Submitted by LeadSongDog
LeadSongDog (1120683) writes "A new paper, complete with pretty pictures, on the arXiv at http://arxiv.org/pdf/1305.7399v1.pdf details some remarkable lessons from a local (inside our galaxy) supernova circa 1900. The formal publication is due to be out in Astrophysical Journal Letters on July 1, and a popsci blurb is available at http://phys.org/news/2013-06-remarkable-supernova.html for the busy readers of /.

Studying the radio and x-ray emissions (synchrotron radiation from energetic electrons at the shockwave front) allowed researchers to find variations in metal distribution around the sphere. They estimate the event produced 10^20kg of electron/positron pairs, nearly all of which have since recombined.

I for one am rather glad I wasn't nearby that day."

Link to Original Source

+ - Time to disable texting from the driver's seat?->

Submitted by LeadSongDog
LeadSongDog (1120683) writes "The good folks at the American Automobile Association's Foundation for Traffic Safety have been funding the University of Utah to examine the distraction of hands-free controls. Fitted up with brain-monitor skullcaps, subjects were shown to be most distracted when they had to focus on voice commands, especially when drafting texts and emails. Once again, we find that multitasking is illusory, something always suffers."
Link to Original Source

"I'm not afraid of dying, I just don't want to be there when it happens." -- Woody Allen