So short in fact, that last year when the looming crisis, which reporters had been covering for years, became official, the price of helium-3 went from $150 per liter to $5,000 per liter.
Group items tagged
Scientists discover how to turn light into matter after 80-year quest - 5 views
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Theoretized 80 years ago was Breit-Wheeler pair production in which two photons result in an electron-positron pair (via a virtual electron). It is a relatively simple Feynmann diagram, but the problem is/was how to produce in practice a high energy photon-photon collider... The collider experiment that the scientists have proposed involves two key steps. First, the scientists would use an extremely powerful high-intensity laser to speed up electrons to just below the speed of light. They would then fire these electrons into a slab of gold to create a beam of photons a billion times more energetic than visible light. The next stage of the experiment involves a tiny gold can called a hohlraum (German for 'empty room'). Scientists would fire a high-energy laser at the inner surface of this gold can, to create a thermal radiation field, generating light similar to the light emitted by stars. They would then direct the photon beam from the first stage of the experiment through the centre of the can, causing the photons from the two sources to collide and form electrons and positrons. It would then be possible to detect the formation of the electrons and positrons when they exited the can. Now this is a good experiment... :) - ...6 more comments...
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True, but isnt it E2=(pc)^2 + (m0c^2)^2 such that for photons E\propto{pc} and for mass E\propto{mc^2}. I agree it will take a lot of energy, but this assumes that that wont be the problem at least. The question therefore is whether the mass flow of the photon rocket (fuel consumed to create photons, eg fission/fusion) is higher/lower than the mass flow for e-p creation. You are probably right that the low e-p cross-section will favour direct use of photons to create low thrust for long periods of time, but with significant power available the ISP might be higher for e-p pair creation.
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In essence the equation tells you that for photons with zero rest mass m0 all the energy will be converted to momentum of the particles. If you want to accelerate e-p then you first spend part of the energy on creating them (~511 keV each) and you can only use the remaining energy to accelerate them. In this case the equation gives you a lower particle momentum which leads to lower thrust (even when assuming 100% acceleration efficiency). ISP is a tricky concept in this case because there are different definitions which clash in the relativistic context (due to the concept of mass flow). R. Tinder gets to a I_SP = c (speed of light) for a photon rocket (using the relativistic mass of the photons) which is the maximum possible relativistic I_SP: http://goo.gl/Zz5gyC .
Wood pulp extract stronger than carbon fiber or Kevlar - 0 views
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The Forest Products Laboratory of the US Forest Service has opened a US$1.7 million pilot plant for the production of cellulose nanocrystals (CNC) from wood by-products materials such as wood chips and sawdust. Prepared properly, CNCs are stronger and stiffer than Kevlar or carbon fibers, so that putting CNC into composite materials results in high strength, low weight products.
Sunlight to jet fuel - European collaboration SOLAR-JET produces first solar kerosene - 4 views
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With the first ever production of synthesized "solar" jet fuel, the EU-funded SOLAR-JET project has successfully demonstrated the entire production chain for renewable kerosene obtained directly from sunlight, water and carbon dioxide (CO2), therein potentially revolutionizing the future of aviation. This process has also the potential to produce any other type of fuel for transport applications, such as diesel, gasoline or pure hydrogen in a more sustainable way.
The Fallout of a Helium-3 Crisis : Discovery News - 3 views
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The science, medical and security uses for helium-3 are so diverse that the crisis banded together a hodge-podge of universities, hospitals and government departments to try and find workable alternatives and engineer ways to recycle the gas they do have.
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So, which shall it be? Are we going to increase the production of hydrogen bombs, or can we finally go back to the Moon (http://en.wikipedia.org/wiki/Helium-3#Extraterrestrial_supplies) ?
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None of these. Either you recycle, or you take it from natural sources on Earth. Although most people don't know - there is plenty of natural He3 on Earth. It's just nonsens to use it for energy production (in fusion reactors) since the energy belance for getting the He3 from these source on Earth is just negative. Or you try to substitute He3.
In the News : Quid, Inc. - 3 views
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Anybody knows them? What mathematic tools are behind their products?
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Wouldn't have guessed
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Francesco, I missed your comments :) :)
Helix Nebula - Helix Nebula Vision - 0 views
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The partnership brings together leading IT providers and three of Europe's leading research centres, CERN, EMBL and ESA in order to provide computing capacity and services that elastically meet big science's growing demand for computing power.
Helix Nebula provides an unprecedented opportunity for the global cloud services industry to work closely on the Large Hadron Collider through the large-scale, international ATLAS experiment, as well as with the molecular biology and earth observation. The three flagship use cases will be used to validate the approach and to enable a cost-benefit analysis. Helix Nebula will lead these communities through a two year pilot-phase, during which procurement processes and governance issues for the public/private partnership will be addressed.
This game-changing strategy will boost scientific innovation and bring new discoveries through novel services and products. At the same time, Helix Nebula will ensure valuable scientific data is protected by a secure data layer that is interoperable across all member states. In addition, the pan-European partnership fits in with the Digital Agenda of the European Commission and its strategy for cloud computing on the continent. It will ensure that services comply with Europe's stringent privacy and security regulations and satisfy the many requirements of policy makers, standards bodies, scientific and research communities, industrial suppliers and SMEs.
Initially based on the needs of European big-science, Helix Nebula ultimately paves the way for a Cloud Computing platform that offers a unique resource to governments, businesses and citizens. -
"Helix Nebula will lead these communities through a two year pilot-phase, during which procurement processes and governance issues for the public/private partnership will be addressed." And here I was thinking cloud computing was old news 3 years ago :)
HAL 9000 Life-Size Replica - 2 views
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I'll just leave this here :) They only cut corners on the lens - which allegedly should be a Nikkor 8mm F8.0, but the latter is rare and much more expensive than the final product itself (if you manage to find one used, that is)
Apple's Incredible Great Best Gorgeous Product Launch Video - 5min.com - 5 views
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For those who still believe in Apple (or perhaps rather for those who don't?) :-)
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Now I need to buy one of the these ....
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Maybe they should innovate by hiring not only designers but also some linguists ...
Suburban space oddities | 1843 - 0 views
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"The forecasts were the product of a series of "summer studies" led by NASA's Ames Research Centre and Stanford University, at which top academics, scientists, and engineers gathered to imagine how future space colonies could look. Artists gave life to the blueprints, producing a stunning series of images that look like a cross between CGI real-estate models (complete with would-be residents smugly sipping wine) and the fantastical worlds of Isaac Asimov."
Phys. Rev. Lett. 108, 153605 (2012): Monolithic Source of Photon Pairs - 0 views
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This is the first time that significant pair production has been demonstrated in a structure that can be electrically self-pumped and which can form the basis for passive optical circuitry, bringing us markedly closer to complete integration of quantum optical technologies.
A 5-Step Technique for Producing Ideas circa 1939 | Brain Pickings - 2 views
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"…the habit of mind which leads to a search for relationships between facts becomes of the highest importance in the production of ideas." Should that be bed reading for all aCT members? :)
Engineers enlist weather model to optimize offshore wind plan | Stanford School of Engi... - 0 views
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Using a sophisticated weather model, environmental engineers at Stanford have defined optimal placement of a grid of four wind farms off the U.S. East Coast. The model successfully balances production at times of peak demand and significantly reduces costly spikes and zero-power events.
Positivity may not ultimately be productive, and not just regarding PH levels - 1 views
Does your iPhone have free will? #arXiv - 3 views
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If you've ever found your iPhone taking control of your life, there may be a good reason. It may think it has free will. That may not be quite as far-fetched as it sounds. Today, one leading scientist outlines a 'Turing Test' for free will and says that while simple devices such as thermostats cannot pass, more complex ones like iPhones might.
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I don't know the inventor of that nonsense that the free will should be the result of QM. It's about the only point I agree with the author of the paper: QM is not necessary and doesn't help. What I meant: all these thought experiments done by typical ultra-naive realists (or ultra-naive physicalists, if you prefer) that cultivate the university departments of physics, computer science etc. are put the cart before the horse. First one has to clarify the role of physical theories and its concepts (e.g. causality) and then one can start to ask how "free will" could perhaps be seen in these theories. More than 200 years ago there existed a famous philosopher named Kant who had some interesting thoughts about this. But authors like Lloyd behave as if he never existed, in fact is view of the world is even pre-Platonic!
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Henry Kissinger How I'm missing yer And wishing you were here
Explosion-Generated Collapsing Vacuum Bubbles Reach 20,000 Kelvin - 1 views
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"In a recent paper published in Physical Review Letters (PRL) Jérôme Duplat and Emmanuel Villermaux developed a method to generate centimeter-sized vacuum bubbles in water with miniature laser-driven explosions, and observed the flash of light produced as the bubble collapsed a not-fully-understood phenomenon known as sonoluminescence." Amazingly they concluded that the temperatrue inside the bubble as it collapses is about 26000 K. At this temperatures some (not me) argue for nuclear fusion... Intriguing stuff!!! Check the videos! Yet another test for the 'Experimental Physics Stagiare' :-)?
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For sure no fusion, that starts appr. from about 20keV, not 20kK. Between both there is still a factor of 11500. What I would rather expect is that the conditions are not appropriate to work with Maxwellian distribution functions. If certain fusion products should be measurable, than this would rather confirm (but not proof) the hypothesis that they do not have Maxwellians but something close to monoenergetic. But most probably they will not measure fusion products, hence no fusion, hence no confusion.
Access : Surface-assisted cyclodehydrogenation provides a synthetic route towards easil... - 0 views
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one step forward .... how many left to get it into commercial products ... and for space?
How to quadruple your productivity with an army of student interns - 6 views
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Potential lessons for out own trainee program?
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well - part of it we already do ... e.g. : (did you see the picture in the report?) "Tolerate a little crowding. It took a little creativity to suddenly find a dozen new workspaces in our two-room office. Fortunately, we've found that a room can always fit one more person-and by induction, you can fit as many as you need. (All those years we spent proving math theorems came in handy after all.) "
Shell energy scenarios to 2050 - 6 views
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just in case you were feeling happy and optimistic
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no - its about Shell globally - all Shell .. these participations are just peanuts please read the intro of the CEO in the pdf you linked to: he does not even mention renewables! their entire sustainability strategy is about oil and gas - just making it (look) nicer and environmentally friendlier
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Fair enough, for me even peanuts are worthy and I am not able to judge. Not all big-profit companies, like Shell, are evil :( Look in the pdf what is in the upstream and downstream you mentionned above. Non-shell sources for examples and more objectivity: http://www.nuon.com/company/Innovative-projects/noordzeewind.jsp http://www.e-energymarket.com/news/single-news/article/ferrari-tops-bahrain-gp-using-shell-biofuel.html thanks.
bookmark - Webmonkey - 0 views
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Google recently launched the Data Liberation Front, an initiative within the company to ensure every one of its products has a clear, easy option for users to export their data in bulk and take their business elsewhere.
The emeritus professor at Edinburgh University, who says he has never sent an email, browsed the internet or even made a mobile phone call, published fewer than 10 papers after his groundbreaking work, which identified the mechanism by which subatomic material acquires mass, was published in 1964.
He doubts a similar breakthrough could be achieved in today's academic culture, because of the expectations on academics to collaborate and keep churning out papers. He said: "It's difficult to imagine how I would ever have enough peace and quiet in the present sort of climate to do what I did in 1964."
Speaking to the Guardian en route to Stockholm to receive the 2013 Nobel prize for science, Higgs, 84, said he would almost certainly have been sacked had he not been nominated for the Nobel in 1980.
Edinburgh University's authorities then took the view, he later learned, that he "might get a Nobel prize - and if he doesn't we can always get rid of him".
Higgs said he became "an embarrassment to the department when they did research assessment exercises". A message would go around the department saying: "Please give a list of your recent publications." Higgs said: "I would send back a statement: 'None.' "
By the time he retired in 1996, he was uncomfortable with the new academic culture. "After I retired it was quite a long time before I went back to my department. I thought I was well out of it. It wasn't my way of doing things any more. Today I wouldn't get an academic job. It's as simple as that. I don't think I would be regarded as productive enough."
Higgs revealed that his career had also been jeopardised by his disagreements in the 1960s and 7