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A new manufacturing process could mean improved efficiency for solar cells. The technique, which is being pioneered by researchers at the University of California, San Diego, results in "hairy" solar cells.

Apparently the peer review process is no better than chance.

For more than a century scientists have relied on the "ergodic theorem" to explain diffusive processes such as the movement of molecules in a liquid. However, they had not been able to confirm experimentally a central tenet of the theorem - that the average of repeated measurements of the random motion of an individual molecule is the same as the random motion of the entire ensemble of those molecules. Now, however, researchers in Germany have measured both parameters in the same system - making them the first to confirm experimentally that the ergodic theorem applies to diffusion.

The first complete theory of how plasmons produce "hot carriers" has been developed by researchers in the US. The new model could help make this process of producing carriers more efficient, which would be good news for enhancing solar-energy conversion in photovoltaic devices.

I did not read the paper but what is further down written in the article, does not give much hope that this actually gives much more insight than what we had nor that it could be used in any way to improve current PV cells soon: e.g. "To fully exploit these carriers for such applications, researchers need to understand the physical processes behind plasmon-induced hot-carrier generation. Nordlander's team has now developed a simple model that describes how plasmons produce hot carriers in spherical silver nanoparticles and nanoshells. The model describes the conduction electrons in the metal as free particles and then analyses how plasmons excite hot carriers using Fermi's golden rule - a way to calculate how a quantum system transitions from one state into another following a perturbation. The model allows the researchers to calculate how many hot carriers are produced as a function of the light frequency used to excite the metal, as well as the rate at which they are produced. The spectral profile obtained is, to all intents and purposes, the "plasmonic spectrum" of the material. Particle size and hot-carrier lifetimes "Our analyses reveal that particle size and hot-carrier lifetimes are central for determining both the production rate and the energies of the hot carriers," says Nordlander. "Larger particles and shorter lifetimes produce more carriers with lower energies and smaller particles produce fewer carriers, but with higher energies."

Its in italian sorry ... but its worth trying to understand ..basically its how an important italian news channel (TG4) gave the rosetta news ... WOW ... middle ages Basically they say ESA spoilt the magic of comets (jesus birth and similar stuff) revealing to the world that it is just a rock and nothing more spending 100 Meuros in the process.

A pearl of the italian national news channels. A comet is nothing more than a dusty rock. Wow, brilliant, such level of understanding of what is happening! Can we use the typhoon control or some other project to get rid of them? They're so confused and ignorant that it's not even clear what their point is, apart from "spoiling the magic of comets", which is not the case.

love this one ... it seems to take physicist to explain to the AI crowd what they are actually doing ... Deep learning is a broad set of techniques that uses multiple layers of representation to automatically learn relevant features directly from structured data. Recently, such techniques have yielded record-breaking results on a diverse set of difficult machine learning tasks in computer vision, speech recognition, and natural language processing. Despite the enormous success of deep learning, relatively little is understood theoretically about why these techniques are so successful at feature learning and compression. Here, we show that deep learning is intimately related to one of the most important and successful techniques in theoretical physics, the renormalization group (RG). RG is an iterative coarse-graining scheme that allows for the extraction of relevant features (i.e. operators) as a physical system is examined at different length scales. We construct an exact mapping from the variational renormalization group, first introduced by Kadanoff, and deep learning architectures based on Restricted Boltzmann Machines (RBMs). We illustrate these ideas using the nearest-neighbor Ising Model in one and two-dimensions. Our results suggests that deep learning algorithms may be employing a generalized RG-like scheme to learn relevant features from data.

Collisionless electrostatic shocks (CES) are the dominant process in heating a plasma when using high power lasers. It turns out that ion-ion collisions actually only play a small role. The ability to create small regions of very high ion energy density on time scales shorter than that of hydrodynamic expansion will be of interest in attempts to understand the processes involved in inertial confinement fusion.

not a surprise though still bad to read ....

On a side note, it's hilarious to read an article on something repeatedly referred to as being secret...

quite self-explanatory described though: "The terrorists apparently would win if Google told you the exact number of times the Federal Bureau of Investigation invoked a secret process to extract data about the media giant's customers. That's why it is unlawful for any record-keeper to disclose it has received a so-called National Security Letter. But under a deal brokered with the President Barack Obama administration, Google on Tuesday published a "range" of times it received National Security Letters demanding it divulge account information to the authorities without warrants. It was the first time a company has ever released data chronicling the volume of National Security Letter requests. National Security Letters allow the government to get detailed information on Americans' finances and communications without oversight from a judge. The FBI has issued hundreds of thousands of NSLs and has even been reprimanded for abusing them. The NSLs are written demands from the FBI that compel internet service providers, credit companies, financial institutions and businesses like Google to hand over confidential records about their customers, such as subscriber information, phone numbers and e-mail addresses, websites visited and more as long as the FBI says the information is "relevant" to an investigation." and ""You'll notice that we're reporting numerical ranges rather than exact numbers. This is to address concerns raised by the FBI, Justice Department and other agencies that releasing exact numbers might reveal information about investigations. We plan to update these figures annually," Richard Salgado, a Google legal director, wrote in a blog post. Salgado was not available for comment. What makes the government's position questionable is that it is required by Congress to disclose the number of times the bureau issues National Security Letters. In 2011, the year with the latest available figures, the FBI issued 16,511 National Sec

long live the sys admins!

careful, NSA is listening... you are now in their blacklist

"Annual Security Inspection at ESTEC"... ... What exactly is this P.R.I.S.M. process that is running on Sophia?

"Cast your name into deep space in style!"

Interesting approach, but with 99.9% probability they will miserably fail (at least in terms of their time schedule) simply because the technology is untested. I haven't read the refs (which miss by the way important works of E. Ahedo et al. on magnetic nozzle acceleration by ambipolar effects), but 1. using water means that you produce oxygen radicals which will erode chamber walls (ionisation efficiency is not 100% and experimental tests haven't been performed yet). 2. Electronic excitation (and radiation), rotational excitation, vibrational excitation, and dissociation are all processes which consume energy and reduce ionisation efficiency drastically. 3. It is a miniaturised Helicon thruster. Theoretical analysis probably does not consider near field effects. Far field models are probably not applicable due to the size of the thruster. I expect some surprises during thruster testing. In any case - good luck!

Apparently, there is only one qualification constraint regarding CubeSat propulsion which is related to volatile propellant. Since they use water as propellant and are also the owner of the CubeSat it is actually up to them how they qualify their thruster. Given that it is also possible to qualify the thruster within 18 months - since they define what "qualification" means.

Bacterial wires explain enigmatic electric currents in the seabed: Each one of these 'cable bacteria' contains a bundle of insulated wires that conduct an electric current from one end to the other. Cable bacteria explain electric currents in the seabed Electricity and seawater are usually a bad mix.

WOW!!!! don't want to even imagine what we do to these with the trailing fishing boats that sweep through sea beds with large masses .... "Our experiments showed that the electric connections in the seabed must be solid structures built by bacteria," says PhD student Christian Pfeffer, Aarhus University. He could interrupt the electric currents by pulling a thin wire horizontally through the seafloor. Just as when an excavator cuts our electric cables. In microscopes, scientists found a hitherto unknown type of long, multi-cellular bacteria that was always present when scientists measured the electric currents. "The incredible idea that these bacteria should be electric cables really fell into place when, inside the bacteria, we saw wire-like strings enclosed by a membrane," says Nils Risgaard-Petersen, Aarhus University. Kilometers of living cables The bacterium is one hundred times thinner than a hair and the whole bacterium functions as an electric cable with a number of insulated wires within it. Quite similar to the electric cables we know from our daily lives. "Such unique insulated biological wires seem simple but with incredible complexity at nanoscale," says PhD student Jie Song, Aarhus University, who used nanotools to map the electrical properties of the cable bacteria. In an undisturbed seabed more than tens of thousands kilometers cable bacteria live under a single square meter seabed. The ability to conduct an electric current gives cable bacteria such large benefits that it conquers much of the energy from decomposition processes in the seabed. Unlike all other known forms of life, cable bacteria maintain an efficient combustion down in the oxygen-free part of the seabed. It only requires that one end of the individual reaches the oxygen which the seawater provides to the top millimeters of the seabed. The combustion is a transfer of the electrons of the food to oxygen which the bacterial inner wires manage over centimeter-long distances. However, s

Hydrothermal deposits on Mars may provide the best opportunity to find Martian biosignatures. Ruff and Farmer report that silica structures created by biotic and abiotic process in hot springs at El Tatio, Chile resemble those found in Gusev crater, thus making it an ideal location for future missions.

proper engineering. do this YouTube sensation and inventor Colin Furze is used to making insane things like retractable wolverine claws, working versions of the hidden blade and rope launcher featured in Assassin's Creed games, and even a homemade Iron Man suit. But this time he decided to do something even crazier and build a hoverbike, and surprisingly, he succeeded and didn't die in the process.

I'm always amazed when that guy doesn't die

A nice read. IBM Watson wowed the tech industry with a 2011 win against two of television show Jeopardy greatest champions. Using something that seemed like a sort of tree search for me IBM DeepQA algorithm managed to ingest sparse data (clues), process it getting one answer, understand what that answer means and come up with the question that leads to that answer. Now, IBM tells us that the same system can tackle medical diagnosis and financial risk problems.

It is typically considered that brain's process of learning is highly energy efficient. While investigating how efficiently the brain can learn new information, physicists have found that, at the neuronal level, learning efficiency is ultimately limited by the laws of thermodynamics.

I hate scorpions, but this could be a nice subject for a future Ariadna study! This north African desert scorpion, doesn't dig burrows to protect itself from the sand-laden wind (as the other scorpions do). When the sand whips by at speeds that would strip paint away from steel, the scorpion is able to scurry off without apparent damage.

Nice research, though they have done almost all the work that we could do in an Ariadna, didnt they? "To check, they took further photographs. In particular, they used a laser scanning system to make a three-dimensional map of the armour and then plugged the result into a computer program that blasted the virtual armour with virtual sand grains at various angles of attack. This process revealed that the granules were disturbing the air flow near the skeleton's surface in ways that appeared to be reducing the erosion rate. Their model suggested that if scorpion exoskeletons were smooth, they would experience almost twice the erosion rate that they actually do. Having tried things out in a computer, the team then tried them for real. They placed samples of steel in a wind tunnel and fired grains of sand at them using compressed air. One piece of steel was smooth, but the others had grooves of different heights, widths and separations, inspired by scorpion exoskeleton, etched onto their surfaces. Each sample was exposed to the lab-generated sandstorm for five minutes and then weighed to find out how badly it had been eroded. The upshot was that the pattern most resembling scorpion armour-with grooves that were 2mm apart, 5mm wide and 4mm high-proved best able to withstand the assault. Though not as good as the computer model suggested real scorpion geometry is, such grooving nevertheless cut erosion by a fifth, compared with a smooth steel surface. The lesson for aircraft makers, Dr Han suggests, is that a little surface irregularity might help to prolong the active lives of planes and helicopters, as well as those of scorpions."

What bugs me (pardon the pun) is that the dimensions of the pattern they used were scaled up by many orders of magnitude, while "grains of sand" with which the surface was bombarded apparently were not... Not being a specialist in the field, I would nevertheless expect that the size of the surface pattern *in relation to* to size of particles used for bombarding would be crucial.

Interesting. these guys are apparently gonna try developing pulsar navigation. They propose to solve the low apparent brightness problem using relatively complex signal processing and filtering to limit the antenna size etc. The say they've already had some promising results using ground based data. worth a science coffee perhaps?

Absolutely. Sante can you get in contact with them?

Interesting mater thesis that lead to the just announced new launcher ! Remember our discussion after the advanced concepts workshop!?!?!

do you know about this? https://www.qb50.eu/launch.php

I knew about the project only, but not about this very interesting missile ... "The launcher has a remarkable track record of several hundred successful launches and only 1 failure. Shtil is marketed by the State Rocket Center Makeyev."

"It works by emitting a burst of light from a femtosecond laser that reflects off visible surfaces - such as an opaque wall - onto objects that are hidden from the camera's direct view. The light then bounces off the object before ultimately making its way back to a detector. This process is repeated a number of times with the laser targeted at different areas of the reflecting surface." nice video