Back to top
Versatile Rigidity in 3D-Printed Resin
A challenge in 3D printing lifelike wearables is mechanical mismatch—the rigidity of electronic devices compared to the natural tissues they aim to replicate. Researchers at Lawrence Livermore and Meta have developed a framework for a new resin material that can be printed at different stiffness levels within a single resin system. Printing a continuous stiffness gradient can better mimic natural structures without the inefficiency of assembling separate elements of different rigidity levels. The team demonstrated the technique with a soft, 3D-printed device worn on a finger and connected to both a smartphone and an air pump that deforms and creates braille letters with the device, essentially translating smartphone text for the sightless.
As described in an article published July 5, 2023, in the journal Matter, researchers used the Digital Light Processing 3D-printing process—a layer-by-layer technique that projects light into liquid resin—to rapidly produce parts. By manipulating the intensity of light applied to the resin, the researchers could control the resin’s rigidity; lower light intensity produced a softer material, while a higher light intensity led to a stiffer material. The material created is stretchable and varies in toughness along its stiffness gradient, making it more versatile than typical rigid electronics. The team further demonstrated the material’s stability under light and ambient conditions. Livermore materials scientist and lead author Sijia Huang says, “One of the requirements we seek for wearable devices is a consistently stable material over the long term. This material is ideal for energy-absorbing materials, soft robotics, and wearable electronics.”
Contact: Sijia Huang (925) 422-3010 (huang55 [at] llnl.gov (huang55[at]llnl[dot]gov)).
Classifying Algal–Bacterial Nutrient Exchanges
Algal–bacterial interactions are critical to photosynthetic carbon dioxide fixation in surface waters. Bacteria are known to provide vitamins, growth hormones, ammonium, and iron-binding compounds to algae, thereby increasing their productivity. In return, algae-associated bacteria are assumed to grow on algal-derived organic material, making these interactions mutualistic. However, few studies have quantified the fraction of bacterial carbon and nitrogen specifically derived from photosynthetic algae, and the reverse—the transfer of bacterial nutrients to algae—has never been quantified. Livermore scientists, in collaboration with researchers from Pacific Northwest National Laboratory, have precisely measured the transfer of carbon and nitrogen between bacteria and algae. Their results were published September 13, 2023, in Nature Communications.
The authors used Livermore’s nanoscale secondary ion mass spectrometer and isotope tracing to measure net exchanges of carbon and nitrogen between algae and 15 species of bacteria. The exchange data, while varied among different strains and cells, was valuable in creating a rubric of bacterial species classification based on their metabolic interactions with algae. These microscopic interactions have consequences for elemental cycling when scaled over entire ecosystems. Algae has important applications in carbon-neutral biofuels and carbon sequestration, which can be maximized by knowing which bacteria enhance nutrient uptake the most. “Understanding the cell-specific activity of microbes in their native environment is critical if we are to predict their responses to climate change,” says Livermore scientist and lead author Xavier Mayali.
Contact: Xavier Mayali (925) 423-3892 (mayali1 [at] llnl.gov (mayali1[at]llnl[dot]gov)).
Livermore Instrument Launched into Space
A high-purity germanium gamma-ray sensor developed by Livermore researchers has departed Earth on a six-year and more than three-billion-kilometer journey to the asteroid Psyche, the largest metal asteroid in the solar system. The instrument is part of a larger gamma-ray spectrometer built in collaboration with researchers from the Johns Hopkins Applied Physics Laboratory and is the second of its kind designed and built by Livermore for space exploration within the last 20 years.
The sensor will determine the elemental composition of Psyche’s surface by measuring the gamma-ray signatures given off by the asteroid due to cosmic ray bombardment. A rare asteroid type, Psyche is thought to be composed largely of iron and nickel, similar to Earth’s core. Other potential elements of interest, such as silicon, potassium, sulfur, and aluminum may also be present. “Psyche is scientifically interesting because the asteroid is thought to be a planetary core, a remnant of a collision during the early stages of the solar system’s development,” says physicist Morgan Burks, who leads the Livermore team. “We believe that exploration of the Psyche asteroid could increase our understanding of the hidden cores of Earth, Mars, Mercury, and Venus.”
NASA’s Psyche spacecraft will arrive at the asteroid in August 2029, where it will remain in orbit for at least 26 months while it collects measurements. Burks and his team are also building gamma-ray spectrometers for two future space missions to the moons of Saturn and Mars, capitalizing on Lawrence Livermore’s expertise in such technology for planetary science.
Contact: Morgan Burks (925) 423-2798 (burks5 [at] llnl.gov (burks5[at]llnl[dot]gov)).
