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Small scale laser induced electron accelerator followed by induced beta decay to produce positrons. Relatively simple, yet requires a high power fs laser and some precision engineering

"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.

"Given that for both craft electricity is supplied by a radioisotope thermoelectric generator (RTGs) powered by the heat given off by the radioactive decay of plutonium - an energy source that decays exponentially with time - Turyshev and others suggested that the extra acceleration could be caused by thermal radiation being emitted from the craft in a preferred direction. "

Can we use it for space ? :P http://www.youtube.com/watch?v=T_QLguHvACs

Sounds relevant. Does ESA need to have a position on this question?

This was on Slashdot now, with a link to the paper. It quite an iteresting study actually. "The scenarios most closely reflecting the reality of our world today are found in the third group of experiments (see section 5.3), where we introduced economic stratification. Under such conditions, we find that collapse is difficult to avoid."

Interesting, but is it new? In general, I would say that history has shown us that it is inevitable that civilisations get replaced by new concepts (much is published about this, read eg Fog of War by Jona Lendering on the struggles between civilisations in ancient history, which have remarkably similar issues as today, yet on a different scale of course). "While some members of society might raise the alarm that the system is moving towards an impending collapse and therefore advocate structural changes to society in order to avoid it, Elites and their supporters, who opposed making these changes, could point to the long sustainable trajectory 'so far' in support of doing nothing." I guess this bang on it, the ones that can change the system, are not benefitted by doing so, hence enrichment, depletion, short term gain remain and might even accelerate to compensate for the loss in the rest of the system.

why am I not surprised .....

http://www.academia.edu/4210419/Can_climate_models_explain_the_recent_stagnation_in_global_warming A view of well-respected scientists on how to proceed from here, that was rejected from Nature. In any case, a long way to go...

unfortunately it's too early to cheer and burn more coal ... there is also a nice podcast associated to this paper from nature Recent global-warming hiatus tied to equatorial Pacific surface cooling Yu Kosaka & Shang-Ping Xie Nature 501, 403-407 (19 September 2013) doi:10.1038/nature12534 Received 18 June 2013 Accepted 08 August 2013 Published online 28 August 2013 Despite the continued increase in atmospheric greenhouse gas concentrations, the annual-mean global temperature has not risen in the twenty-first century1, 2, challenging the prevailing view that anthropogenic forcing causes climate warming. Various mechanisms have been proposed for this hiatus in global warming3, 4, 5, 6, but their relative importance has not been quantified, hampering observational estimates of climate sensitivity. Here we show that accounting for recent cooling in the eastern equatorial Pacific reconciles climate simulations and observations. We present a novel method of uncovering mechanisms for global temperature change by prescribing, in addition to radiative forcing, the observed history of sea surface temperature over the central to eastern tropical Pacific in a climate model. Although the surface temperature prescription is limited to only 8.2% of the global surface, our model reproduces the annual-mean global temperature remarkably well with correlation coefficient r = 0.97 for 1970-2012 (which includes the current hiatus and a period of accelerated global warming). Moreover, our simulation captures major seasonal and regional characteristics of the hiatus, including the intensified Walker circulation, the winter cooling in northwestern North America and the prolonged drought in the southern USA. Our results show that the current hiatus is part of natural climate variability, tied specifically to a La-Niña-like decadal cooling. Although similar decadal hiatus events may occur in the future, the multi-decadal warming trend is very likely to continue with greenhouse gas

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.

one more, France will have one officially by July, so who's next?

Protons, neutrons melt to produce 'quark-gluon plasma' at RHIC .... hot stuff

posted already further down

Francesco pointed out this research one year ago, we dropped it as noone was really considering it ... but in space a low CPU power consumption is crucial!! Maybe we should look back into this?

I don't remember what is the speed factor, but I guess this might do it! Although, I remember when using an IMU that you cannot have the data above a given rate (e.g. 20Hz even though the ADC samples the sensor at a little faster rate), so somehow it is not just the CPU that must be re-thought. When I say qualification I also imply the "hardened" phase.

I don't know if the (promised) one-order-of-magnitude improvements in power efficiency and performance are enough to justify looking into this. For once, it is not clear to me what embracing this technology would mean from an engineering point of view: does this technology need an entirely new software/hardware stack? If that were the case, in my opinion any potential benefit would be nullified. Also, is it realistic to build an entire self-sufficient chip on this technology? While the precision of floating point computations may be degraded and still be useful, how does all this play with integer arithmetic? Keep in mind that, e.g., in the Linux kernel code floating-point calculations are not even allowed/available... It is probably possible to integrate an "accelerated" low-accuracy floating-point unit together with a traditional CPU, but then again you have more implementation overhead creeping in. Finally, recent processors by Intel (e.g., the Atom) and especially ARM boast really low power-consumption levels, at the same time offering performance-boosting features such as multi-core and vectorization capabilities. Don't such efforts have more potential, if anything because of economical/industrial inertia?

That's the lab I worked...

just being cinical ... but did not we know that g = 9.809 in Paris? I can also create a complex measurement procedure that will held pi = 3.1415, just as expected!!!

well, sure... the interest of such gravimeter is to be absolute, and for now slightly more accurate than the other type of absolute gravimeter which uses retroreflector and interferometry ( http://en.wikipedia.org/wiki/Gravimeter ). While the latter ones reached their limit in term of sensitivity, the atomic ones can be enhanced in many ways (using cooler atoms, better optics, etc...)

These animal sustain 700g. We should have a look at this

I think Lucas didn't know he would have such an impact in science with Star Wars...!

do you think it could be the dark side of The Force?

what else...?

"WASHINGTON, D.C. - In a three-month investigation, a team of Northwestern University student reporters has found that the US nation's security establishment is not adequately prepared for many of the environmental changes that are coming faster than predicted and that threaten to reshape demands made on the military and intelligence community. This is despite the fact that the Defense Department has called climate change a potential "accelerant of instability." The Medill School of Journalism graduate student team began publication on January 10 of its findings on the national security implications of climate change with a series of print, video and interactive stories."

good open-access journal

This is really cool. I know one of the authors and he is a good guy... the only thing that leaves me unsatisfied is that if the whole issue is related to thermal effects one should have seen the Pioneer effect all the time and not only at about 10 AU... ...or is there some thermal process that kicked in only at this distance?

Here's an update on this theory: NASA Releases New Pioneer Anomaly Analysis "The mysterious force acting on the Pioneer spacecraft seems to be falling exponentially. That's a strong clue that on-board heat is to blame, says NASA." Heat emission 'most likely cause' of pioneer anomaly "What's more interesting is that, contrary to the original analysis conducted all those years ago, the deceleration does seem to be decelerating at an exponential rate -- just as one might expect from the radioactive decay of plutonium-238, which powers the two spacecraft. Turyshev concludes, "The most likely cause of the Pioneer anomaly is the anisotropic emission of on-board heat.""

Not exactly new, but apparently never appeared on Diigo. I'm very sceptical about the topic (of course!), but interesting thoughts anyway.

looooong paper ...

Greenwich could lose its place at the centre of global time if a move to "atomic time" is voted in by the International Telecommunication Union in Geneva in January 2012.

Haha this is really a British article... Already since 1972 we don't use GMT but UTC, which is based on atomic clocks. However British continue to call it GMT... The question is to drop the leap second in UTC, and France is definitely for this change (for scientific motives of course...;) I don't see how this is connected to winter time however... And they shouldn't worry Greenwich is still the beginning of the world with 0 degree longitude !

"the end of GMT as an international standard could accelerate the move to keep British Summer Time into the winter, letting us have lighter evenings." As I understand it, if GMT looses its "prestigious" status, then it would be easier to push through all-year BST in UK.

At a meeting of the American Geophysical Union in San Francisco in December, he reported an average figure that was between 0.005 and 0.008 per cent greater than the value for Earth's mass established by the International Astronomical Union. A disc of dark matter around the equator 191 kilometres thick and 70,000 km across can explain this, he says. Harris has yet to account for perturbations to the satellites' orbits due to relativity, and the gravitational pull of the sun and moon. Maybe relativistic GPS could improve this even further? As a side note however, the Juno spacecraft flyby showed an gravity acceleration which matched the calculations, casting doubts on the earlier calculations.