Friday, October 2, 2015

Big trees first to die in severe droughts
Image from SciAm.

Physics and gravity are factors large trees have to deal with. Imagine trying to suck up water from a straw that is 5 feet tall versus a few inches, said Nathan McDowell, a researcher with the Earth and Environmental Sciences Division at the Los Alamos National Laboratory in New Mexico.

“Being tall, it’s harder to suck water,” said McDowell, a co-author of the paper. In fact, he said, big trees do a lot for a forest ecosystem that their smaller counterparts cannot. Some species, such as the spotted owl, only live in big trees. Large trees provide shade for the forest ecosystem and keep the understory of forests cool and more humid. (Full story)

Also from Smithsonian Science News

Study reveals urban smoke absorbs sunlight, exacerbating climate warming
Downtown Los Angeles, from EPA.

The new measurements resolve carbon particles that are of several types, each with its own effect on climate,” said project leader Manvendra Dubey of Los Alamos National Laboratory.

“Black carbon, from both city-related biomass combustion, is the most sunlight absorbing. Brown carbon, from sources such as residential wood combustion and forest fires, is the component that is missing in most climate models and can be a significant absorber of sunlight, making it as bad for climate warming as black carbon,” Dubey said. (Full story)

Physicists observe weird quantum fluctuations of empty space—maybe
NASA image.

Empty space is anything but, according to quantum mechanics: Instead, it roils with quantum particles flitting in and out of existence. Now, a team of physicists claims it has measured those fluctuations directly.

"There are many experiments that have observed indirect effects of vacuum fluctuations," says Diego Dalvit, a theorist at Los Alamos National Laboratory in New Mexico who was not involved in the current work. "If this [new experiment] is correct, it would be the first direct observation of the field [of fluctuations] itself." (Full story)

Titan helps unpuzzle decades-old plutonium perplexities
Comparison of prediction (right) with
experimental observations (left) from ORNL.

Lead scientist Marc Janoschek of Los Alamos National Laboratory and his team performed neutron scattering experiments to obtain physical confirmation to prove once and for all that plutonium's dynamical magnetism wasn't just a theory. In his recent paper published in the journal Science Advances, Janoschek discussed the team's findings.

From the ARCS measurements, the team determined the fluctuations carry varying numbers of electrons in plutonium's outer valence shell. This determination also explained why abnormal changes occur in the differing phases of plutonium's volume. (Full story)

Why Jeff Bezos, Peter Thiel, and others are betting on fusion
Tri-Alpha Energy in Irvine, Calif., has reportedly
raised $140 million. Tri-Alpha photo 

At this point no one knows which—if any—of these private-sector ventures will prevail, and achieving fusion won’t be easy. Says Glen Wurden, a team leader at the plasma physics group at Los Alamos National Laboratory.

“To get funding, small companies have to promise the moon. There’s a long history where promises have been made and not kept. When you hear a private company say it will have a technology in five years, you roll your eyes.” Critics also say these startups are building on technology that was rejected decades ago by government labs or that still hasn’t been proved. (Full story)

Enzymatic fuel cells are creeping slowly along thanks to gold nanoclusters
Gold clusters, LANL image.

Los Alamos tackled one key problem, which is the ability of the enzyme-active sites to accept and donate electrons. The problem is that the active sites are typically “buried” under the surface of the enzymes, making it difficult to transfer electrons back and forth to the electrode.

The solution was to develop a mediator or “relaying agent” that would enhance electron transfer, and more specifically, one that requires the least amount of energy input to get the job done. (Full story)

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