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Thijs Versloot

Solar singlet fission bends the laws of physics to boost solar power efficiency by 30% ... - 2 views

www.extremetech.com/...t-solar-power-efficiency-by-30

technology science

shared by Thijs Versloot on 19 May 15 - No Cached
LeopoldS and Paul N liked it
  • Thijs Versloot on 19 May 15
     
    Chemists at UCR have found a way of turning a single photon into two excitons, by a process known as singlet fission. By doubling the yield of excitons in a solar cell, you theoretically double the number of electrons produced and could lead to having a max theoretical efficiency of 60% or more in an (organic) solar cell See also DOI: 10.1021/jz500676c - "Singlet Fission: From Coherences to Kinetics"
Beniamino Abis

Laser-Plasma Particle Accelerator - 1 views

www.sciencedaily.com/...130620132412.htm

technology PHY

shared by Beniamino Abis on 21 Jun 13 - No Cached
  • Beniamino Abis on 21 Jun 13
     
    Can we have one?
  • johannessimon81 on 21 Jun 13
     
    They say they create 2 GeV electrons in a very small setup. However the laser they use is more than 10 meters in length. Still a really nice result.
  • Thijs Versloot on 24 Jun 13
     
    Compared to a 27km circumference this is major achievement and it is indeed already foreseen that future colliders will include this technology as beam fillers and pre-accelerators at some point. The technique is quite elegant and a lot more energy efficient. Nevertheless, there are also thoughts that future particle colliders might actually go towards space and study collisions orginating from extremely energetic cosmic particles
Thijs Versloot

Engineers identify how to keep surfaces dry underwater - 1 views

phys.org/...15-08-surfaces-underwater.html

technology

shared by Thijs Versloot on 24 Aug 15 - No Cached
johannessimon81 and jcunha liked it
  • Thijs Versloot on 24 Aug 15
     
    When submerged, water tends to cling to the top of the spikes, while air and water vapor accrue in the pores between them. The combination of trapped air and water vapor within these cavities forms a gaseous layer that deters moisture from seeping into the surface below. More materials with amazing properties. Might even be usefull for liquid fuel tanks?
  • johannessimon81 on 01 Sep 15
     
    I don't quite see how the trapped water vapor keeps the water out of the cavities... since the vapor is at the same low temperature as the water it should hardly exert any pressure at all. One would expect though that surface tension keeps water out of smaller cavities because it tries to minimize surface area. If the water would enter the cavities it would need increase its surface area dramatically which in turn is energetically unfavorable. Interesting application would also be in non-wetting electronics which might make cooling of circuitry a lot easier: you just sink your data center.
jcunha

Interference of thermal waves - Can heat be controlled as waves? - 1 views

phys.org/...can-heat-be-controlled-as.html

technology PHY solid state thermal management science

shared by jcunha on 26 Jun 15 - No Cached
  • jcunha on 26 Jun 15
     
    Imagine a material that only admits thermal conduction for certain temperatures. Martin Maldovan from Georgia Tech holds a tiny thermoelectric device that turns cold on one side when current is applied. Recent research has focused on the possibility of using interference effects in phonon waves to control heat transport in materials. These are exciting news (see Nature Materials paper here http://www.nature.com/nmat/journal/v14/n7/full/nmat4308.html). Heterostructure research lead to outstanding new possibilities when applied to electronic transport (e.g. in quantum well and quantum dots) and to photonics (e.g. Quantum Cascade Laser tunnable lasers). Apparently the time has come to see selective thermal control in this way! Truly exciting!!
Daniel Hennes

V3Solar puts a new spin on PV efficiency - 1 views

www.gizmag.com/...24352

technology NRG

shared by Daniel Hennes on 03 Sep 15 - No Cached
jcunha liked it
  • Daniel Hennes on 03 Sep 15
     
    "V3Solar has developed a cone-shaped solar energy harvester that is claimed to generate over 20 times more electricity than a flat panel thanks to a combination of concentrating lenses, dynamic spin, conical shape, and advanced electronics."
  • Thijs Versloot on 04 Sep 15
     
    Hmm.. that seems counter intuitive... how would it ever be that much better than a flat panel? Rotating the PV will only make sure only parts are illuminated. Operating temperature is a better argument, but that comes at the cost of exposure. Came across this little gem of a webpage, maybe we should outsource our impossibility EM drive work next time? :) https://www.metabunk.org/debunked-v3solars-spinning-solar-panel-cone-spin-cell-coolspin.t1166/
Thijs Versloot

Electromagnetism generated by symmetry breaking in dielectrics - 0 views

phys.org/...tism-enable-antennas-chip.html

science technology antenna electromagnetism

shared by Thijs Versloot on 09 Apr 15 - No Cached
  • Thijs Versloot on 09 Apr 15
     
    Using dielectric materials as efficient EM radiators and receivers can scale down these antenna's to the chip level, reducing both weight and power consumption. The infamous internet-of-things one step closer. But could we also transmit power this way?? "In dielectric aerials, the medium has high permittivity, meaning that the velocity of the radio wave decreases as it enters the medium," said Dr Dhiraj Sinha, the paper's lead author. "What hasn't been known is how the dielectric medium results in emission of electromagnetic waves. This mystery has puzzled scientists and engineers for more than 60 years." The researchers determined that the reason for this phenomenon is due to symmetry breaking of the electric field associated with the electron acceleration The researchers found that by subjecting the piezoelectric thin films to an asymmetric excitation, the symmetry of the system is similarly broken, resulting in a corresponding symmetry breaking of the electric field, and the generation of electromagnetic radiation.
pacome delva

Physics - Electronics without solids - 0 views

physics.aps.org/...PhysRevLett.103.140405

phy atomtronics cold_atoms

shared by pacome delva on 01 Oct 09 - Cached
  • The idea is to someday use such a circuit to study basic many-body physics in a completely controlled and adjustable system, without the messiness of crystal defects or impurities found in real semiconductors.
pacome delva

Nanofibres power portable electronics - 1 views

physicsworld.com/...43243

phy nan nanofibres

shared by pacome delva on 21 Jul 10 - Cached
  • Juxi Leitner on 21 Jul 10
     
    cool, is there somebody coming to work on materials? and stuff like that?
jmlloren

Exotic matter : Insight : Nature - 5 views

www.nature.com/...index.html

nan phy

shared by jmlloren on 03 Aug 10 - Cached
LeopoldS liked it
  • jmlloren on 03 Aug 10
     
    Trends in materials and condensed matter. Check out the topological insulators. amazing field.
  • ...12 more comments...
  • Luzi Bergamin on 03 Aug 10
     
    Aparently very interesting, will it survive the short hype? Relevant work describing mirror charges of topological insulators and the classical boundary conditions were done by Ismo and Ari. But the two communities don't know each other and so they are never cited. Also a way to produce new things...
  • jmlloren on 04 Aug 10
     
    Thanks for noticing! Indeed, I had no idea that Ari (don't know Ismo) was involved in the field. Was it before Kane's proposal or more recently? What I mostly like is that semiconductors are good candidates for 3D TI, however I got lost in the quantum field jargon. Yesterday, I got a headache trying to follow the Majorana fermions, the merons, skyrnions, axions, and so on. Luzi, are all these things familiar to you?
  • Luzi Bergamin on 04 Aug 10
     
    Ismo Lindell described in the early 90's the mirror charge of what is now called topological insulator. He says that similar results were obtained already at the beginning of the 20th century... Ismo Lindell and Ari Sihvola in the recent years discussed engineering aspects of PEMCs (perfect electro-megnetic conductors,) which are more or less classical analogues of topological insulators. Fundamental aspects of PEMCs are well knwon in high-energy physics for a long time, recent works are mainly due to Friedrich Hehl and Yuri Obukhov. All these works are purely classical, so there is no charge quantisation, no considerations of electron spin etc. About Majorana fermions: yes, I spent several years of research on that topic. Axions: a topological state, of course, trivial :-) Also merons and skyrnions are topological states, but I'm less familiar with them.
  • LeopoldS on 04 Aug 10
     
    "Non-Abelian systems1, 2 contain composite particles that are neither fermions nor bosons and have a quantum statistics that is far richer than that offered by the fermion-boson dichotomy. The presence of such quasiparticles manifests itself in two remarkable ways. First, it leads to a degeneracy of the ground state that is not based on simple symmetry considerations and is robust against perturbations and interactions with the environment. Second, an interchange of two quasiparticles does not merely multiply the wavefunction by a sign, as is the case for fermions and bosons. Rather, it takes the system from one ground state to another. If a series of interchanges is made, the final state of the system will depend on the order in which these interchanges are being carried out, in sharp contrast to what happens when similar operations are performed on identical fermions or bosons." wow, this paper by Stern reads really weired ... any of you ever looked into this?
  • jmlloren on 04 Aug 10
     
    C'mon Leopold, it's as trivial as the topological states, AKA axions! Regarding the question, not me!
  • LeopoldS on 04 Aug 10
     
    just looked up the wikipedia entry on axions .... at least they have some creativity in names giving: "In supersymmetric theories the axion has both a scalar and a fermionic superpartner. The fermionic superpartner of the axion is called the axino, the scalar superpartner is called the saxion. In some models, the saxion is the dilaton. They are all bundled up in a chiral superfield. The axino has been predicted to be the lightest supersymmetric particle in such a model.[24] In part due to this property, it is considered a candidate for the composition of dark matter.[25]"
  • jmlloren on 04 Aug 10
     
    Thank's Leopold. Sorry Luzi for being ironic concerning the triviality of the axions. Now, Leo confirmed me that indeed is a trivial matter. I have problems with models where EVERYTHING is involved.
  • Luzi Bergamin on 04 Aug 10
     
    Well, that's the theory of everything, isn't it?? Seriously: I don't think that theoretically there is a lot of new stuff here. Topological aspects of (non-Abelian) theories became extremely popular in the context of string theory. The reason is very simple: topological theories are much simpler than "normal" and since string theory anyway is far too complicated to be solved, people just consider purely topological theories, then claiming that this has something to do with the real world, which of course is plainly wrong. So what I think is new about these topological insulators are the claims that one can actually fabricate a material which more or less accurately mimics a topological theory and that these materials are of practical use. Still, they are a little bit the poor man's version of the topological theories fundamental physicists like to look at since electrdynamics is an Abelian theory.
  • jmlloren on 04 Aug 10
     
    I have the feeling, not the knowledge, that you are right. However, I think that the implications of this light quantum field effects are great. The fact of being able to sustain two currents polarized in spin is a technological breakthrough.
  • LeopoldS on 04 Aug 10
     
    not sure how much I can contribute to your apparently educated debate here but if I remember well from my work for the master, these non-Abelian theories were all but "simple" as Luzi puts it ... and from a different perspective: to me the whole thing of being able to describe such non-Abelian systems nicely indicates that they should in one way or another also have some appearance in Nature (would be very surprised if not) - though this is of course no argument that makes string theory any better or closer to what Luzi called reality ....
  • Luzi Bergamin on 04 Aug 10
     
    Well, electrodynamics remains an Abelian theory. From the theoretical point of view this is less interesting than non-Abelian ones, since in 4D the fibre bundle of a U(1) theory is trivial (great buzz words, eh!) But in topological insulators the point of view is slightly different since one always has the insulator (topological theory), its surrounding (propagating theory) and most importantly the interface between the two. This is a new situation that people from field and string theory were not really interested in.
  • Dario Izzo on 04 Aug 10
     
    guys... how would you explain this to your gran mothers?
  • jmlloren on 05 Aug 10
  • LeopoldS on 07 Aug 10
     
    *you* tried *your* best .... ??
LeopoldS

Investigating Machine Identification Code Technology in Color Laser Printers | Electron... - 0 views

www.eff.org/...echnology-color-laser-printers

INF gadget defence

shared by LeopoldS on 14 Oct 10 - Cached
  • LeopoldS on 14 Oct 10
     
    I assume that our fancy colour printer also have this "feature" ... 
Dario Izzo

Electronic Nose - 3 views

science.nasa.gov/...06oct_enose.htm

smell nose olfactory

shared by Dario Izzo on 03 Mar 10 - Cached
  • Dario Izzo on 03 Mar 10
     
    NASA worked on this 4 years ago.... good inspiration for a possible alternative application to navigation
Juxi Leitner

Baby-by-Number: Parents' New Obsession With Data | Wired Science | Wired.com - 0 views

www.wired.com/...baby-tracking

tech babies

shared by Juxi Leitner on 14 Dec 09 - Cached
  • Even the folks at LeapFrog caution that electronic toys shouldn’t replace the tried-and-true childhood staples of previous generations. Plain old wooden blocks can be an incredibly valuable learning tool, says Jim Gray, a former child development researcher who now heads the learning team at LeapFrog.
  • Juxi Leitner on 14 Dec 09
     
    for the dad's out there...
pacome delva

Algae Show a Knack for Quantum Mechanics -- Berardelli 2010 (203): 3 -- ScienceNOW - 1 views

sciencenow.sciencemag.org/...3

phy bio quantum_physics photosynthesis

shared by pacome delva on 04 Feb 10 - Cached
  • the discovery will open up a new field of research, and it could lead to a new generation of superefficient light-sensitive devices.
  • the experiments showed that the electron vibrations resulting from the photons striking the antennas persisted at full strength four times longer than expected. The reason, the researchers report this week in Nature, is that quantum mechanics controls the energy. "It was an utter surprise," says physical chemist and co-author Gregory Scholes of the University of Toronto in Canada. For the results to have occurred, he explains, a property called quantum coherence must have been operating.
  • the research "will open an entirely new area of biophysics." And that effort should have "huge implications," he says, "not only for how we think about biophysics, but also light harvesting and light-sensitive devices."
  • pacome delva on 04 Feb 10
     
    Very interesting work, showing that apparently algae mastered quantum coherence a few years before us... Inspiring for a new type of light-sensitive devices, and perhaps other applications...
Joris _

Are cosmic rays really causing Toyota's woes? | freep.com | Detroit Free Press - 2 views

www.freep.com/...ys-really-causing-Toyotas-woes

space electronic

shared by Joris _ on 16 Mar 10 - Cached
LeopoldS liked it
  • Luzi Bergamin on 16 Mar 10
     
    Sounds like one of Calvin's alibis: Aliens! Dad, aliens! A sarcastic Venusian entered the kitchen...
  • nikolas smyrlakis on 16 Mar 10
     
    i think they could also be a cause for Greece's economic crisis
  • Luzi Bergamin on 16 Mar 10
     
    Well, then I suggest to elect Spaceman Spiff instead of Papandreou as Prime Minister! :-)
Joris _

Hewlett-Packard Unveils Real-World Memristor, Chip of the Future | Popular Science - 3 views

www.popsci.com/...d-unveils-first-ever-memristor

technology electronic

shared by Joris _ on 12 Apr 10 - Cached
LeopoldS liked it
  • they allow the same device to serve as the processor and the memory
  • a memristor system would work far faster, and with far less energy, than a traditional computer.
  • Second, memristors can be much smaller than transistors.
  • ...1 more annotation...
  • Lastly, unlike transistors, which only work linearly, memristors can form three-dimensional networks
  • pacome delva on 15 Apr 10
     
    wow, looks pretty cool! I wonder what is "a ridiculous amount of memory on a chip"...? giga, tera, peta, exa, ... ?
  • Ma Ru on 15 Apr 10
     
    Looks cool indeed, but as with all those technology "breakthroughs" my enthusiasm will be limited until this actually makes it to my laptop...
  • LeopoldS on 15 Apr 10
     
    what a phrase: "this advance could increase the power and memory of computers to nearly unimaginable proportions within only a couple of years." ... sure ....
Luís F. Simões

The Fantastical Promise of Reversible Computing  - Technology Review - 2 views

www.technologyreview.com/...26308

INF reversible logic computing chip electronics quantum cellular_automata

shared by Luís F. Simões on 25 Jan 11 - No Cached
  • Reversible logic could cut the energy wasted by computers to zero. But significant challenges lie ahead.
  • By some estimates the difference between the amount of energy required to carry out a computation and the amount that today's computers actually use, is some eight orders of magnitude. Clearly, there is room for improvement.
  • There are one or two caveats, of course. The first is that nobody has succeeded in building a properly reversible logic gate so this work is entirely theoretical. But there are a number of computing schemes that have the potential to work like this. Thapliyal and Ranganathan point in particular to the emerging technology of quantum cellular automata and show how their approach might be applied.
  • ...1 more annotation...
  • Ref: arxiv.org/abs/1101.4222: Reversible Logic Based Concurrent Error Detection Methodology For Emerging Nanocircuits
  • Dario Izzo on 26 Jan 11
     
    We did look at making computation powers more efficient from the bio perspective (efficiency of computations in brain). This paper was actually the base for our discussion on a new approsach to computing http://atlas.estec.esa.int/ACTwiki/images/6/68/Sarpeshkar.pdf and led to several ACT internal studies
  • Luís F. Simões on 26 Jan 11
     
    here is the paper I told you about, on the computational power of analog computing: http://dx.doi.org/10.1016/0304-3975(95)00248-0 you can also get it here: http://www.santafe.edu/media/workingpapers/95-09-079.pdf
Luís F. Simões

New algorithm offers ability to influence systems such as living cells or social networks - 3 views

www.sciencedaily.com/...110512104220.htm

control complex_networks complex networks

shared by Luís F. Simões on 13 May 11 - No Cached
Joris _ liked it
  • a new computational model that can analyze any type of complex network -- biological, social or electronic -- and reveal the critical points that can be used to control the entire system.
  • Slotine and his colleagues applied traditional control theory to these recent advances, devising a new model for controlling complex, self-assembling networks.
  • Yang-Yu Liu, Jean-Jacques Slotine, Albert-László Barabási. Controllability of complex networks. Nature, 2011; 473 (7346): 167 DOI: 10.1038/nature10011
  • LeopoldS on 14 May 11
     
    Sounds too super to be true, no?
  • ...3 more comments...
  • LeopoldS on 15 May 11
     
    cover story in the May 12 issue of Nature
  • LeopoldS on 15 May 11
     
    For each, they calculated the percentage of points that need to be controlled in order to gain control of the entire system.
  • LeopoldS on 16 May 11
  • Ma Ru on 17 May 11
     
    > Sounds too super to be true, no? Yeah, how else may it sound, being a combination of hi-quality (I assume) research targeted at attracting funding, raised to the power of Science Daily's pop-pseudo-scientific journalists' bu****it? Original article starts with a cool sentence too: > The ultimate proof of our understanding of natural or technological systems is reflected in our ability to control them. ...a good starting point for a never-ending philosophers' debate... Now seriously, because of a big name behind the study, I'm very curious to read the original article. Although I expect the conclusion to be that in practical cases (i.e. the cases of "networks" you *would like to* "control"), you need to control all nodes or something equally impractical...
  • LeopoldS on 18 May 11
     
    then I am looking forward to reading your conclusions here after you will have actually read the paper
Luís F. Simões

Bitcoin P2P Currency: The Most Dangerous Project We've Ever Seen - 10 views

launch.is/...dangerous-project-weve-ev.html

bitcoin p2p money disruptive

shared by Luís F. Simões on 16 May 11 - No Cached
LeopoldS liked it
  • After month of research and discovery, we’ve learned the following:1. Bitcoin is a technologically sound project.2. Bitcoin is unstoppable without end-user prosecution.3. Bitcoin is the most dangerous open-source project ever created.4. Bitcoin may be the most dangerous technological project since the internet itself.5. Bitcoin is a political statement by technotarians (technological libertarians).*6. Bitcoins will change the world unless governments ban them with harsh penalties.
  • The benefits of a currency like this:a) Your coins can’t be frozen (like a Paypal account can be)b) Your coins can’t be trackedc) Your coins can’t be taxedd) Transaction costs are extremely low (sorry credit card companies)
  • An individual with the name -- or perhaps handle -- of Satoshi Nakamoto first wrote about bitcoins in a paper called Bitcoin: A Peer-to-Peer Electronic Cash System.
  • ...1 more annotation...
  • * We made this term up to describe the “good people” of the internet who believe in the fundamental rights of individuals to be free, have free speech, fight hypocrisy and stand behind logic, technology and science over religion, political structure and tradition. These are the people who build and support things like Wikileaks, Anonymous, Linux and Wikipedia. They think that people can, and should, govern themselves. They are against external forms of control such as DRM, laws that are bought and sold by lobbyists, and religions like Scientology. They include splinter groups that enforce these ideals in the form of hacktivism, such as the takedown of the Sony Playstation Network after Sony tried to prosecute a hacker for unlocking its console.
  • Ma Ru on 17 May 11
     
    Sounds good!
  • ...9 more comments...
  • pacome delva on 18 May 11
     
    wow it's frigthening! it's the dream of every anarchist, every drug, arm, human dealer! the world made as a global fiscal paradise... the idea is clever however it will not replace real money because 1 - no one will build a fortune on bitcoin if a technological breakthrough can ruin them 2 - government never allowed parallel money to flourish on their territory, so it will be almost impossible to change bitcoin against euros or dollars
  • Nicholas Lan on 18 May 11
     
    interesting stuff anyone read cryptonomicon by neal stephenson? similar theme.
  • Luís F. Simões on 18 May 11
     
    :) yes. One of the comments on reddit was precisely drawing the parallels with Neal Stephenson's Snowcrash / Diamond Age / Cryptonomicon. Interesting stuff indeed. It has a lot of potential for misuse, but also opens up new possibilities. We've discussed recently how emerging technologies will drive social change. Whether it's the likes of NSA / CIA who will benefit the most from the Twitters, Facebooks and so on, by gaining greater power for control, or whether individuals are being empowered to at least an identical degree. We saw last year VISA / PayPal censoring WikiLeaks... Well, here's a way for any individual to support such an organization, in a fully anonymous and uncontrollable way...
  • tvinko on 18 May 11
     
    One of my colleagues has made a nice, short write-up about BitCoin: http://www.pds.ewi.tudelft.nl/~victor/bitcoin.html
  • LeopoldS on 18 May 11
     
    very nice analysis indeed - thanks Tamas for sharing it!
  • pacome delva on 20 May 11
     
    mmm I'm not an expert but it seemed to me that, even if these criticisms are true, there is one fundamental difference between the money you exchange on internet via your bank, and bitcoins. The first one is virtual money and the second one aims at being real, physical, money, even if digital, in the same way as banknotes, coins, or gold.
  • nikolas smyrlakis on 20 May 11
     
    An algorithm wanna-be central bank issuing untraceable tax free money between internet users? not more likely than the end of the world supposed to take place tomorrow, in my opinion. Algorithms don't usually assault women though !:P
  • LeopoldS on 21 May 11
     
    well, most money is anyway just virtual and only based on expectations and trust ... (see e.g. http://en.wikipedia.org/wiki/Money_supply) and thus if people trust that this "money" has some value in the sense that they can get something of value to them in exchange, then not much more is needed it seems to me ...
  • pacome delva on 23 May 11
     
    @Leopold: ok let's use the rigth words then. Bitcoin aim at being a currency ("physical objects generally accepted as a medium of exchange" from wikipedia), different than the "demand deposit". In the article proposed by Tamas he compares what cannot be compared (currencies, demand deposits and their mean of exchange). The interesting question is wether one can create a digital currency which is too difficult to counterfeit. As far as I know, there is no existing digital currency except this bitcoins (and maybe the currencies from games as second life and others, but which are of limited use in real world).
  • nikolas smyrlakis on 23 May 11
     
    well of course money is trust, and even more loans and credit and even more stock and bond markets. It all represents trust and expectations. However since the first banks 500 years ago and the first loans etc. etc., and as well the fact that bonds and currencies bring down whole countries (Greece lately), and are mainly controlled by large financial centres and (central) banks, banks have always been on the winning side no matter what and that isn't going to change easily. So if you are talking about these new currencies it would be a new era, not just a new currency. So should Greece convert its debt to bitcoins ;P ?
  • pacome delva on 23 May 11
     
    well, from 1936 to 1993 the central bank of france was owned by the state and was supposed to serve the general interest...
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