Lab Report

Get the latest LLNL coverage in our weekly newsletter

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.

March 10, 2023

quinn

The publication HPCwire announced Lawrence Livermore National Laboratory’s Deputy Associate Director for High Performance Computing (HPC) Terri Quinn has been named among its “People to Watch” for 2023.

Watch out

HPCwire, the leading publication for news and information for the high performance computing industry, today unveiled its People to Watch for 2023. This feature highlights key community members who are driving the industry forward, people you should be keeping an eye on in the year to come.

Over the course of the program, HPCwire has recognized 200 HPC luminaries who have gone on to achieve extraordinary things. One dozen additional individuals are being honored in 2023, the 21st year of the People to Watch program.

Lawrence Livermore National Laboratory’s Deputy Associate Director for High Performance Computing (HPC) Terri Quinn was named one of the recipients this year.

In her role as Livermore’s deputy AD of HPC, Quinn establishes long-range directions and priorities for the Lab’s Computing Directorate and for the Multiprogrammatic and Institutional Computing program, which provides cost-effective computing services to LLNL programs and scientists. Quinn also is associate program director for Livermore Computing (LC) for the Weapons Simulation and Computing program, where among other responsibilities, she is helping Chief Technology Officer for LC Bronis de Supinski prepare for the exascale-class supercomputer El Capitan. El Capitan is scheduled for delivery at LLNL later in 2023.

metal am

To address the issue of missing struts and strut defects in 3D-printed metallic lattice structures, a Lawrence Livermore National Laboratory team has investigated the ability to monitor build quality during the printing process to decide, on-the-fly, if the part will satisfy quality requirements. Lab 70th anniversary lattice printed by Gabe Guss. Photo by Jean-Baptiste Forien/LLNL.

In real time

A team of engineers and scientists from Lawrence Livermore National Laboratory (LLNL), has developed a method for detecting and predicting strut defects in additively manufactured metal lattice structures during the build stage in real time. The process, involving a combination of monitoring, imaging techniques and multi-physics simulations, enables users to determine if the part will satisfy quality requirements at the earliest possible stage.

The high-strength and low-density properties of metallic lattices have found applications in many fields. However, during the Laser Powder Bed Fusion (LPBF) process, missing or defective struts can occur that affect the mechanical behavior of the lattice structure. To ensure quality, scientists typically perform a post-build inspection, which takes time and is not always possible, especially with complex builds.

As described in a paper recently published in Additive Manufacturing Letters, LLNL researchers monitored the Additive Manufacturing of a metallic micro-lattice structure using a photodiode, a pyrometer — both of which measure light emitted from the melt pool — and thermal imaging. The team produced normal struts and intentionally defective 'half-struts' through the LPBF process, measuring the thermal emissions from the melt pool. The researchers then developed a method to use those thermal emissions to predict defects with high accuracy.

biomarker

Dedicated vapor generation set-up for controlled exposure of plants to chemical warfare agents. (A) Schematic view. (B) Photo of vapor generation set-up. Image courtesy of at TNO Defence.

Biomarkers can ID few and far between

Chemical weapons remain a problem despite their prohibition under the Chemical Weapons Convention. Because these agents are often volatile and reactive, they don’t persist in the environment. Clues in the biology of victims can provide essential evidence but obtaining such samples is difficult.

Researchers at TNO Defence in the Netherlands decided to look back to the environment, specifically plants. Samples from plants, unlike humans, are easy to collect, transport and store without the additional complications of being medical samples. Their research shows the nerve agents sulfur mustard, sarin, chlorine and Novichok nerve agent A-234 break down in plants to form specific and detectable protein adducts, meaning part of the nerve agent is added to a protein within the plant.

Katelyn Mason, a biochemist at the Lawrence Livermore National Laboratory, said: “the impact of this research cannot be understated, especially in the case of chlorine-based plant biomarkers because verification of the use of chlorine has remained elusive to forensic efforts for decades.”

The tricky problem of chlorine gas detection isn’t completely solved though. Chlorine releasing products such as household bleach can mimic the same effect, resulting in a false positive. However, while the group found some of the same biomarkers formed between the two, they expect bleach and chlorine gas to also have unique biomarkers. This is the next obstacle the group aims to tackle which, if successful, will allow them to definitively distinguish between bleach cleaners and chlorine gas attacks.

z machine

Sandia National Laboratories Z-machine. Image courtesy of Sandia National Laboratories.

tunis

It’s raining, it’s pouring, a core full of iron

The Earth’s iron core was formed by iron rain that fell on the liquid mantle when the Earth was first forming. These are the conclusions from studies concerning the true nature of the vaporization of iron using the Sandia National Laboratories Z machine, the world’s most powerful radiation source. The discovery that iron rain formed the Earth’s core and not molten iron from collisions was reported in the edition of the journal Nature Geoscience.

Scientists from Lawrence Livermore National Laboratory, Sandia, Harvard University and the University of California at Davis used the Z machine to replicate conditions that existed when the Earth was first formed. The researchers found that the minimum pressure needed to vaporize iron is much lower than previously thought. The lower energy needed to vaporize iron resulted in an iron rain created on the Earth’s surface that penetrated the molten layers of the Earth. The heavier iron particles eventually collected at the center of the Earth forming the molten iron core that exists today.

The new discovery of the lower pressure needed to vaporize iron explains why the Earth’s moon does not have an iron core. The lower gravity of the moon prevented iron vapor created at the same time the Earth’s core formed from penetrating to the center of the moon.