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I wonder how much energy you can extract from the ocean in a responsible way... Mixing up different thermal layers would probably a quite an influence on ecology.

The last available assessment report on the ecological impact seems to date from 1981 which would need to be brought up to current standards. On the other hand, this system could have a positive influence on fish population as deep cold water brings nutrients to the surface. The cold water could also be used to lower sea surface temperatures and affect hurricane genesis!

"Within a few years we will see the first true prototype of a spaceship that will take us between worlds," Worden said. this sounds to me a bit too much like Pete Worden :-) but I really like this one :-) One of those billionaires might be Google's Larry Page, who is keenly interested in space travel and NASA Ames's research. "Larry asked me a couple weeks ago how much it would cost to send people one way to Mars and I told him $10 billion, and his response was, 'Can you get it down to 1 or 2 billion?,'" Worden told the Long Now audience. "So now we're starting to get a little argument over the price."

This link has a nice concise explanation of helium escaping the atmosphere. http://www.astronomynotes.com/solarsys/s3.htm (this link describes the mechanics of particles escaping the atmosphere, this includes escape velocity, thermal and nonthermal process) http://www.springerlink.com/content/k094u75188h64516/fulltext.pdf ( and if you are really interested, this paper discuss helium in the atmosphere (production and loss) in much more detail )

Cilia are hairs driven by molecular motors. They are found in monocellular organisms, etc. If we can build such things artificially, we have micro-pumps etc. Any space usability?

carlo's distributed actuator study originally considered cilia as well as peristaltic motion if i remember right. i suppose you might still think about debris transport for digging applications. Originally there was an idea for thermal transport aswell which, it turns out, was bollocks.

more transformation optics ... 

I still believe that it is worth to check the thermal, mechanical and chemical properties of the developed metamaterials. For hyperbolic re-entries the radiation is still the dominating heat load source and a dominating bandwith may be indentified. A resistive metamaterial should be placed on the nose cap of the entry body in order to reduce local radiation heat load.

Sante, Luzi have a look at this???!!!

Leo, you mean that they measured 3 years? That's not a point to criticize: since the only interaction of neutrinos with matter is the Weak Interaction (which is indeed very, very weak), it is extremely hard to get a reasonable statistic. By the same reason, it's essentially impossible to shield the experiment from the background. And this background (solar neutrinos, cosmic radiation neutrinos) is huge.

for sure a result to be taken seriously. It makes a buzz in my lab... but always be cautious with this kind of declaration, that hugely violates all physics we know and even most of the reasonable alternative theories... Remember the Pionneer anomaly for which it took almost ten years to set up that finally its a thermal effect.

as with my last post: how long could such distances get? ready for SPS?

how "large" could these distances be? - ready for SPS?

I don't think that the distance is the important criteria... It seems that the directivity is of the order of a laser one, so the divergence will be equivalent. Perhaps the important criteria is that the cost of these type of light sources could be cheaper...? and also perhaps what power transmission is achievable? It seems also that now that this concept could be used for to focus cheap lasers, instead of using complex optics in cd-rom players, etc... see http://news.softpedia.com/news/Highly-Directional-Semiconductor-Laser-Created-at-Harvard-90839.shtml

this is the project I was referring to in my topic post ...

Looking for some Mars images? You don't have to steal from www.google.com/mars... Take them directly from the provider :-)

Very nice simulation of a heated liquid.

interesting energy/SPS paper

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.

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.

Mitsubishi Heavy Industries said Friday that it has succeeded in transmitting 10 kW of power through 500 m. An announcement that comes just after JAXA scientists reported one more breakthrough in the quest for Space Solar Power Systems (http://phys.org/news/2015-03-japan-space-scientists-wireless-energy.html). One step closer to Power Generation from Space/

from the press release (https://www.mhi-global.com/news/story/1503121879.html) "10 kilowatts (kW) of power was sent from a transmitting unit by microwave. The reception of power was confirmed at a receiver unit located at a distance of 500 meters (m) away by the illumination of LED lights, using part of power transmitted". So 10kW of transmission to light a few efficient LED lights??? In a 2011 report (https://www.mhi-global.com/company/technology/review/pdf/e484/e484017.pdf), MHI estimated this would generate the same electricity output as a 400-megawatt thermal plant - or enough to serve more than 150,000 homes during peak hours. The price? The same as publicly supplied power, according to its calculations. There are no results to boost these claims however. The main work they do now is focused on beam steering control. I guess the real application in mind is more targeted to terrestrial applications, eg wireless highway charging (http://www.bbc.com/future/story/20120312-wireless-highway-to-charge-cars). With the distances so much shorter, leading to much smaller antenna's and rectenna's this makes much more sense to me to develop.

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."

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.

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.

Like it! Can you do an initial assessment on space applications Jojo?

is this the breaktrough that we were waiting for?

That depends on what application you are thinking of. For circuit board electronics this will allow integration of micro sized supercapacitors to provide operational power. They will have to be fed by external batteries still, but the close proximity allows for better tailored power demands. They also propose tapping into thermal/mechanical energy to charge the supercaps. In the end, they can provide significant specific power (W/kg) but you still need to upscale the production to cover large areas to also gain high specific energy (Wh/kg). This breakthough is for micro sized applications, not for replacement of large scale energy storage (electric vehicles, satellites) going up to kWh. That said, I know of several studies in supercaps at ESA, but they are still qualifying current relatively old commercial solutions.

Imagine if your clothing could, on demand, release just enough heat to keep you warm and cozy, allowing you to dial back on your thermostat settings and stay comfortable in a cooler room. Or, picture a car windshield that stores the sun's energy and then releases it as a burst of heat to melt away a layer of ice.

interesting indeed: Such chemically-based storage materials, known as solar thermal fuels (STF), have been developed before, including in previous work by Grossman and his team. But those earlier efforts "had limited utility in solid-state applications" because they were designed to be used in liquid solutions and not capable of making durable solid-state films, Zhitomirsky says. The new approach is the first based on a solid-state material, in this case a polymer, and the first based on inexpensive materials and widespread manufacturing technology. Read more at: http://phys.org/news/2016-01-material-harvest-sunlight-day-demand.html#jCp