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Luís F. Simões

heat shields: NASA's Orion capsule vs. SpaceX's Dragon capsule - 0 views

  • NASA has 50 years of experience with reentry capsules, but is fearful of trying something new. SpaceX has no reentry experience and chooses the most efficient engineering approach. Guess whose capsule is overweight and still sitting on the ground? Guess whose capsule completed a successful first flight yesterday?
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    Powerful contrast between the two pictures!!
Juxi Leitner

Technology Review: Blogs: arXiv blog: Physicist Discovers How to Teleport Energy - 4 views

  • He gives the example of a string of entangled ions oscillating back and forth in an electric field trap, a bit like Newton's balls. Measuring the state of the first ion injects energy into the system in the form of a phonon, a quantum of oscillation. Hotta says that performing the right kind of measurement on the last ion extracts this energy. Since this can be done at the speed of light (in principle), the phonon doesn't travel across the intermediate ions so there is no heating of these ions. The energy has been transmitted without traveling across the intervening space.
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    wonder if we can use that to power a moon base .... or on-board a SBSP satellite
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    will still have to read the actual article but am a bit sceptic if this interpretation really will hold ... what are our fundamental physicists saying about this?
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    I am not the physicist but I thought it might be interesting, from a space security point-of-view
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    Yes it seems really interesting and opens new possibilities. However this technology review article is not very good and the guy uses terms which have a precise meaning (like teleportation), which is different from the word we know... Quantum teleportation is what we use for designing quantum computers, but we are quite far from any practical applications. This energy teleportation will allow new scheme involving energy (if it is experimentally confirmed) which is very nice. However it seems this occurs in an entangled many-body system, which the only macroscopic one I know is a bose-eintein condensate (BEC). So it would mean infuse energy in the BEC by doing a measurement on one of the atom and extract it few millimeters away by doing a measurement on another atom. very far from any long distance power transmission...
Luís F. Simões

Russian Physicists Solve Radio Black-Out Problem for Re-Entering Spacecraft  ... - 1 views

  • When spacecraft return to Earth, one of the tensest parts of the mission is the radio black out that occurs as the vehicle re-enters the atmosphere. Travelling at hypersonic speeds of between Mach 8 and 15, the spacecraft heats and breaks down molecules in the atmosphere causing a plasma to form. It is this plasma sheath that prevents radio communication.
  • Ref: arxiv.org/abs/0704.3103: Communication Through Plasma Sheaths
nikolas smyrlakis

Climate change and warfare: Cool heads or heated conflicts? | The Economist - 0 views

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    Too warm to fight? History shows that conflicts were happening in colder periods
pacome delva

Researchers Use Radio Waves to "See" Through Walls -- Berardelli 2009 (1015): 2 -- Scie... - 0 views

  • Researchers have discovered that an array of radio transceivers--devices that send and receive signals--can track people's movements behind walls. Possible uses include detecting people trapped in burning buildings, controlling lighting or heating and cooling systems as people enter or exit rooms, and spotting burglars or enemy soldiers.
pacome delva

Photonic Thermos | Physical Review Focus - 0 views

  • The pure vacuum of a thermos is not the best possible insulator for keeping your soup warm. Last year a team found theoretically that a structure known as a photonic crystal could block heat flow even more effectively than vacuum.
Joris _

Global warming: Our best guess is likely wrong - 0 views

  • theoretical models cannot explain what we observe in the geological record
  • There appears to be something fundamentally wrong
  • something other than carbon dioxide caused much of the heating during the PETM
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    I find the title of the article misleading at best, but probably plainly wrong since they seem to talk about conditions way back and I am not sure how well our current models have been designed to work in these very different conditions? - but should probably be rather another good reason to put more effort into improving the models!
pacome delva

101 uses for guar gum - 0 views

  • Guar gum, a polysaccharide, is a cheap and environmentally friendly material produced naturally by a leguminous shrub.
  • The film has a high tensile strength and Kadokawa says it can conduct electricity as efficiently as semi-conductors.   Uniquely, the film hardens upon heating but becomes soft again as it cools. These properties mean that it could be used to produce temperature sensors.
ESA ACT

A Sound Way To Turn Heat Into Electricity - 0 views

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    another energy conversion system... could be very interesting for nuclear power sources and other fields. more details in a few days
Thijs Versloot

A Groundbreaking Idea About Why Life Exists - 1 views

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    Jeremy England, a 31-year-old assistant professor at the Massachusetts Institute of Technology, has derived a mathematical formula that he believes explains this capacity. The formula, based on established physics, indicates that when a group of atoms is driven by an external source of energy (like the sun or chemical fuel) and surrounded by a heat bath (like the ocean or atmosphere), it will often gradually restructure itself in order to dissipate increasingly more energy. This could mean that under certain conditions, matter inexorably acquires the key physical attribute associated with life. The simulation results made me think of Jojo's attempts to make a self-assembling space structure. Seems he may have been on the right track, just not thinking big enough
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    :-P Thanks Thijs... I do not agree with the premise of the article that a possible correlation of energy dissipation in living systems and their fitness means that one is the cause for the other - it may just be that both go hand-in-hand because of the nature of the world that we live in. Maybe there is such a drive for pre-biotic systems (like crystals and amino acids), but once life as we know it exists (i.e., heredity + mutation) it is hard to see the need for an amendment of Darwin's principles. The following just misses the essence of Darwin: "If England's approach stands up to more testing, it could further liberate biologists from seeking a Darwinian explanation for every adaptation and allow them to think more generally in terms of dissipation-driven organization. They might find, for example, that "the reason that an organism shows characteristic X rather than Y may not be because X is more fit than Y, but because physical constraints make it easier for X to evolve than for Y to evolve." Darwin's principle in its simplest expression just says that if a genome is more effective at reproducing it is more likely to dominate the next generation. The beauty of it is that there is NO need for a steering mechanism (like maximize energy dissipation) any random set of mutations will still lead to an increase of reproductive effectiveness. BTW: what does "better at dissipating energy" even mean? If I run around all the time I will have more babies? Most species that prove to be very successful end up being very good at conserving energy: trees, turtles, worms. Even complexity of an organism is not a recipe for evolutionary success: jellyfish have been successful for hundreds of millions of years while polar bears are seem to be on the way out.
Thijs Versloot

The Worlds Smallest Thermometer - 0 views

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    By attaching a diamond crystal to an AFM tip, researcher at New York City University managed to measure the heat flows at atomic levels in resistors. The method works due to a vacancy in the carbon lattice, two spots are empty of which one is filled with a nitrogen atom. The energy state of the vacancy is temperature dependent and can actually be read out spectroscopically.
Nina Nadine Ridder

New 'self-healing' gel makes electronics more flexible - 1 views

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    Maybe something to look at for Ricarda? Researchers in the Cockrell School of Engineering at The University of Texas at Austin have developed a first-of-its-kind self-healing gel that repairs and connects electronic circuits, creating opportunities to advance the development of flexible electronics, biosensors and batteries as energy storage devices. "There's no need for heat or light to fix the crack or break in a circuit or battery, which is often required by previously developed self-healing materials." Yu and his team created the self-healing gel by combining two gels: a self-assembling metal-ligand gel that provides self-healing properties and a polymer hydrogel that is a conductor.
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    Ricarda??
marliesarnhof

MIT and newly formed company launch novel approach to fusion power | MIT News - 1 views

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    Scientists anticipate the output would be more than twice the power used to heat the plasma, achieving the ultimate technical milestone: positive net energy from fusion.
LeopoldS

The Moon's mantle unveiled - 2 views

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    first science results reported in Nature (as far as I know) from the Yutu-2 and Chang'e mission .... and they look very good!
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    Sure they are very useful! It will be even better if they manage to fit the data to modeled circulation of the lunar magma ocean that was formed posterior to the "Theia" body collision with Earth. The collision was the cause of the magma ocean in the first place. The question now is how this circulation pattern of the lava-moon "froze" in time upon phase transition to solid. Because, what crystallizes last in sequence, is more rich in "incompatible" with the crystal structure, elements, we might combine data+models to predict their location. Those incompatible tracers are mainly radioactively decaying elements that produce heat (google publications about lunar KREEP elements (potassium (K), rare earth elements(REE), and phosphorus(P)). By knowing where the KREEP is: - we know where to dig for them mining (if they are useful for something, eg. Phosphorus for plants to be grown on the Moon) - we avoid planning to build the future human colony on top of radioactives, of course. The hope is that the Moon, due to lack of plate tectonics, has preserved this "signature of the freezing sequence". Let's see.
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    thanks Nasia! very interesting comment
jaihobah

Black Hole Power: How String Theory Idea Could Lead to New Thermal-Energy Harvesting Te... - 0 views

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    A new class of exotic materials could find its way into next-generation technologies that efficiently convert waste heat into electrical current according to new research. Both the exotic materials and the means by which they generate electricity rely on a hybrid of advanced concepts-including string theory combined with black holes combined with cutting-edge condensed matter physics.
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    Sounds spooky
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