Bubbling Up Geothermal Sees Big Global Growth

While geothermal power remains a relatively niche source of renewable energy, it is still a piece of the puzzle. EarthTechling reports that global production is set to double over the next few years - Bubbling Up: Geothermal Sees Big Global Growth.

Global geothermal power capacity could be on its way toward doubling, according to a new industry report, as projects unfold around the world, with a number of countries closing in on putting their first geothermal power stations to work.

The Geothermal Energy Association, in its 2013 Geothermal Power: International Market Overview, said seventy countries are moving forward with nearly seven hundred projects. The group said that as of August this year, 11,765 megawatts of geothermal capacity were online – and 11,776 MW of new capacity were in the early stages of development or under construction.

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The next big thing 4D printing

Smart Planet has a post on "4D printing" (making objects that can assemble themselves) - The next big thing: 4D printing.

Just as 3D printing has started to come into its own, some forward-thinking architect has just announced that he’s already working on the next big thing.

It was at this year’s TED conference in Long Beach that Skylar Tibbits, an MIT professor, gave attendees a sneak peak into an even more advanced manufacturing innovation he’s calling 4D printing — naturally. I know the name seems suspect because, frankly, what the heck is a 4D printed object? Well, rest assured that it’s not something that exists in some hidden spatial realm (what use would we have for that?). Rather it’s run-of-the-mill three dimensional printing technology, but combined with a neat enhancement that allows the parts to self-assemble and re-assemble into a myriad number of products.

The device that’s used is a Stratasys 3D printer designed to produce multi-layered materials. Each part will be comprised of a regular rigid plastic layer, along with an outer layer made of “smart” materials. When submerged in water, the “smart” material absorbs and expands, causing the parts to move and form a pre-specified object. “Essentially the printing is nothing new, it is about what happens after,” Tibbits says.

The capacity for this one extra step creates a suddenly wider range of possibilities. Anything that requires intricate assembly like furniture, bikes and cars would require less manpower. “Imagine a scenario where you go to Ikea and buy a chair, put it in your room and it self-assembles,” said Carlo Olguin, principal research scientist at the software firm, told the BBC.

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Big Bang Theory Saved

From the title you might think that the theory was in serious peril. But it wasnt, really.

Big Bang Theory Saved

An apparent discrepancy in the Big Bang theory of the universes evolution has been reconciled by astrophysicists examining the movement of gases in stars.

Professor John Lattanzio from Monashs School of Mathematical Sciences and Director of the Centre for Stellar and Planetary Astrophysics said the confusion surrounding the Big Bang revolved around the amount of the gas Helium 3 in the universe.

The issue arises from what is actually one of the greatest successes of the big bang theory – quantitative calculations of the relative abundances of a few light element produced within the first 5-10 minutes of the universe by the process of "big bang" nucleosynthesis.

Detailed calculations depend on vaious factors, such as the temperature and rate of expansion of the universe during the time in question, as well as the densities and relative abundances of the "raw materials" (mostly protons, neutrons, photons, and neutrinos) when nucleosynthesis begins. The calculations are complex due to the dependence on so many factors, but theyre no real sweat with modern computers. Even before modern computers, the first physicists to make the computations (George Gamow and associates) in the late 1940s were able to come up with surprisingly good results, all things considered. (They predicted a mass fraction of about 50% helium-4, when the correct figure is more like 25%.)

The objective is to compute the abundances of the light elements deuterium (hydrogen-2), helium-3, helium-4, lithium-6, and lithium-7 (relative to protons – ordinary hydrogen). In order to check the correctness of the calculations, the numbers have to be compared with actual measurements of the relative abundances of these elements, either at the present time, or at some known time in the past.

And thats where the difficulties lie. In the first place, its necessary to be sure the relative abundances can be measured accurately. This is nontrivial, since, in the most extreme case, the predicted abundance of lithium-7 is a minuscule mass ratio on the order of 10^-10. (Lithium-6 is an even smaller ratio, too small to measure.)

The second problem is that theres no way to observe the relative abundances right after nucleosynthesis is complete. At best, the measurement could be made a billion years or so after the big bang. And in practice, the best measurements are made on nearby objects, corresponding to more than 13 billion years after the big bang. So you have to make allowances for any changes that could have occurred in that time span, due to incremental production or destruction of isotopes (in stars, for example).

The most problematic case has been with helium-3. Until the research just reported, there has been much less helium-3 detected than should be expected, because this isotope can be produced in low mass star like our sun. But the discrepancy can now be accounted for, since this helium-3 should be destroyed near the end of a stars life:

Near the end of a stars life there is a core flash and it was at around this time that the computer models revealed a small instability in the movement of the gases in the star. "When we looked at this in 3D we found this hydrodynamic instability caused mixing and destroyed the helium 3 so that none was released into space," Professor Lattanzio said.

Additional information:

Deep Mixing of ³He: Reconciling Big Bang and Stellar Nucleosynthesis – original research report in Science (subscription rqd for full access)

On the case of the "missing" helium – PhysicsWeb

Scientists crack open stellar evolution – Lawrence Livermore National Laboratory

Nucleosynthesis


Tags: astrophysics, big bang, nucleosynthesis

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