Lab Report

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The Lab Report is a weekly compendium of media reports on science and technology achievements at Lawrence Livermore National Laboratory. Though the Laboratory reviews items for overall accuracy, the reporting organizations are responsible for the content in the links below.

Mar. 23, 2018

Ben Santer

Setting the record straight

Ben Santer has clung to sheer granite walls. He’s hoisted himself onto narrow ledges. He’s inched his way to survival out of a deep, dark and deadly crevasse.

Decades of high-stakes mountaineering have prepared the Lawrence Livermore National Laboratory scientist to defend his work in climate change.

Santer’s conclusion -- that human activities are warming Earth’s surface -- have triggered searing criticism from climate change contrarians. He has refused to stay silent when people assert that human-fueled activities aren’t warming the planet.

“They’re wrong. Demonstrably wrong,” Santer said. Soft-spoken and meticulous, he picks his words as carefully as he chooses his routes over rocks. “It was necessary to set the record straight,” he said.

High-speed images of a common laser-based metal 3D printing process, coupled with newly updated computer models, have revealed the mechanisms behind material redistribution, a phenomenon that leads to defects in printed metal parts.

Seeing the flaws through the metal

Metal additive manufacturing has struggled with quality assurance, but it’s an essential hurdle for the technology to overcome before it can see widespread adoption for volume production. As with any industrial process, there are numerous potential sources of error in metal powder bed fusion (PBF), such as low-quality feedstocks and insufficient laser power.

A team of scientists at Lawrence Livermore and SLAC National Accelerator Laboratory are working to identify these sources of error and help manufacturers avoid them in the future. Their research involves 3D printing sample parts inside an X-ray characterization chamber.

LLNL's approach is a bit different as scientists are using thermal imaging and optical imaging at very high framerates to follow the dynamics on the surface.

Deflecting the massive asteroid 101955 Bennu was the focus of recent research by a national planetary defense team. Bennu will make a very close approach to Earth on Sept. 25, 2135.

Hammering away at Bennu

In the unlikely event an asteroid dubbed Bennu does threaten to collide with Earth in 2135, NASA's proposed "Hammer" spacecraft will be no match for the incoming celestial mass.

Lawrence Livermore scientists are part of a national defense team that developed the Hammer, short for Hypervelocity Asteroid Mitigation Mission for Emergency Response, a proposed NASA spacecraft meant to deflect any stellar body that might threaten Earth. Scientists say the sheer size of Bennu would be too much for the Hammer.

The 29-foot-tall, 8.8-ton Hammer spacecraft works by ramming a kinetic impactor into it, delivering a gentle nudge large enough and soon enough to slow it down and change its collision course with Earth, but not so large that the object breaks apart.

The Hammer also can destroy a threatening celestial mass using a nuclear bomb, but that as seen as a last-ditch option considering the possible disastrous consequences.

LLNL researchers created the most realistic-to-date simulation of a 7.0 earthquake along the Hayward Fault.

Of seismic proportions

What would happen if a major earthquake hit one of the Bay Area's main fault lines? Researchers at the Lawrence Livermore National Laboratory used new technology to simulate a 7.0-magnitude quake on the northern section of the Hayward Fault.

In the simulation, the earthquake starts at the very northern section of the fault near Richmond and ends near Hayward. A 7.0 earthquake would be felt across the entire Bay Area, with the ripples of shaking spreading to the South Bay within about 15 seconds.

The simulation is color-coded to show how strong the shaking would be in different areas. Blue means the earthquake would be felt, but not cause significant damage. A reddish-orange color indicates a ground velocity of one meter per second, which researchers say would damage buildings.

What sets this simulation apart from previous ones is that it factors in three-dimensional geological structure and topography.

Time-integrated image of a laser-driven shock compression experiment to recreate planetary interior conditions and study the properties of superionic water. Image by M. Millot/E. Kowaluk/J.Wickboldt/LLNL/LLE/NIF

That zany water

Scientists have confirmed the existence of superionic ice water that occupies a simultaneously liquid and solid state. Though it doesn’t exist anywhere on Earth, it’s possible that it might exist on Uranus and Neptune. It might finally help us understand why those planets’ magnetic fields are so crooked.

Structurally, superionic ice water (or superionic ice or superionic water) is composed of hydrogen atoms moving around inside a solid, unyielding lattice of oxygen atoms.

Under normal circumstances, liquid water comprises a V-shape of two hydrogen atoms bonded to one oxygen atom and expands when it freezes from a liquid state into a solid one. But researchers from the Lawrence Livermore National Laboratory have  shown that in more extreme environments, like those found on Uranus and Neptune, intense heat could melt those bonds. This would let hydrogen ions pass through, but intense pressure would still hold the structure together -- giving the water the characteristics of both solid and liquid matter.