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.

May 25, 2019

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ice
In this artistic rendering of the laser compression experiment, high power lasers focus on the surface of a diamond, generating a sequence of shock waves that propagate throughout the sample assembly (from left to right), simultaneously compressing and heating the initially liquid water sample, forcing it to freeze into the superionic water ice phase.

Not your ordinary ice cubes

When you think of ice, you probably picture the cubes in your freezer. But ice can take all kinds of different forms, and recently a group of scientists managed to recreate one of the most exotic kinds of ice in their lab, thanks to a collection of super-powered lasers.

The kind of ice we’re most familiar with is a specific type called Ice I. Ice has almost two dozen other types, like Ice II, which forms when you start applying pressure to normal ice. With more pressure you’d get Ice XV, then Ice VIII, then Ice X, and so on. You could find even more different varieties of ice at different pressures and temperatures, and these variations have distinct appearances and properties.

To find some of the more exotic types of ice, researchers at Lawrence Livermore National Laboratory constructed a very complicated experiment: They would trap water inside a tightly confined space and blast it with high-powered lasers. Altogether, the researchers used six lasers at the University of Rochester’s Laboratory for Laser Energetics to get the job done.

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microcapsule
LLNL scientists have discovered they can use machine learning to automate microencapsulation quality control in real-time, devising an algorithm to determine “good” capsules from “bad” and developing a valve-based mechanism that can sort them without human intervention. Illustration by Jacob Long/LLNL

Hands off my microcapsules

Micro-Encapsulated CO2 Sorbents (MECS) — tiny, reusable capsules full of a sodium carbonate solution that can absorb carbon dioxide from the air — are a promising technology to capture carbon from the atmosphere.

To date, this process of creating microcapsules has required constant monitoring, a mundane task for operators. But LLNL scientists have discovered they can use machine learning to automate microencapsulation quality control in real-time, devising an algorithm to determine “good” capsules from “bad” and developing a valve-based mechanism that can sort them without human intervention.

LLNL scientists said the image-based machine learning algorithm can detect problem capsules and trigger a response up to 40 times per second, eliminating the monotonous task of monitoring microcapsule manufacture. Furthermore, these capabilities should translate to other applications for microcapsules beyond carbon capture, such as medicine, cosmetics or food additives.

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drought
New research indicates humans could have caused droughts for more than 900 years.

Climate is in a hot spot

Climate change caused by humans could have caused droughts as far back as the beginning of the 20th century, according to a recent Lawrence Livermore study.

Scientists looked at data on the climate, as well as on tree rings dating back to 900 years, providing insight into moisture levels in soil over a long period of time.

The team showed that as the amount of greenhouse gasses pumped into the atmosphere rose following the industrial revolution, droughts spiked between 1900 and 1949. They then dropped between 1950 and 1975, when more aerosols were used: chemicals that can affect how much it rains and how clouds form. Since 1981, drought levels rose again, likely due to the rise in greenhouse gas emissions and government crackdowns on the use of aerosols. The team predicts the trend will continue in the coming years.

“The human consequences of this, particularly drying over large parts of North America and Eurasia, are likely to be severe,” the authors warned.

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graphene
Graphene aerogel is one graphene composite that can be produced through SLA 3D printing.

Exploring the possibilities of graphene in 3D

As discoveries around graphene applications abound, many are wondering if it can be scaled to 3D. This could have revolutionary effects. The 3D printing of graphene has appeared impossible because of its structure. But if it’s mixed with a binder, you’re in luck.

One creative approach to graphene 3D printing comes from a collaboration between Lawrence Livermore and Virginia Tech College of Engineering. The research team has developed a new way to 3D print graphene that’s capable of making precise objects formed into any shape you can think of.

The process starts with making a graphene oxide hydrogel. Graphene oxide is a compound similar to graphene, but with oxide integrated with the carbon atoms. The hydrogel is a 3D structure made from polymer chains with cross-links holding the polymer chains together.

The graphene-oxide is then broken apart with ultrasound, and the light-sensitive polymer (hydrogel) is added. Now, research shows it’s possible to use this graphene oxide hydrogel as a resin for 3D printing with micro-stereolithography (SLA) technology. The result is a 3D object that contains graphene-oxide, which gives the printed part a large majority of the properties of graphene.

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microbe
In a microbial footrace between different species, a fast-growing cell outperforms other cell types, as long as it enjoys the comforts of pure culture. But in real-world conditions, like those found in soil (no shoes, no sugary energy drinks, rough ground), the slower cell types can gain the lead. Image by Northern Arizona University

Dishing the dirt

Soil microbes are wild, unpampered and uncultured.

But to understand their ecology, don't look in laboratory cultures, look in the soil. That's exactly what Lawrence Livermore National Laboratory and Northern Arizona University (NAU) scientists did.

Relationships between microbial genes and performance are often evaluated in the lab in pure cultures, with little validation in nature. The team showed that genomic traits related to laboratory measurements of maximum growth potential failed to predict the growth rates of bacteria in real soil.

"It's very difficult to measure microbial growth in situ," said LLNL's Jennifer Pett-Ridge. "But we use a new method developed by our collaborators in Bruce Hungate's lab at NAU, called quantitative stable isotope probing. It makes all the difference."