April 16, 2021
Biomarkers of chlorine gas exposure in plants included small molecules such as 2,4,6-trichlorophenol and peptides in which tyrosine residues (shown) were chlorinated.
Plant tissue marks the spot
When used as a chemical weapon, chlorine gas disperses so rapidly that evidence of its release can be hard to find.
“With most nerve agents, we have biomarkers that are stable in the environment that we look for to confirm [the agents’] use, but no biomarkers have been verified and accepted by the scientific community for the case of chlorine,” said Katelyn Mason, a researcher in the Forensic Science Center at the Lawrence Livermore National Laboratory. “It’s a major gap in forensics.”
At the American Chemical Society Spring 2021 meeting, Mason reported that she and her colleagues have identified biomarkers in plant tissue that might be forensic tools for confirming chlorine-gas release.
A standoff detonation of a nuclear device irradiates an asteroid and deposits energy at and beneath the surface. In this work, two neutron yields (50 kt and 1 Mt) and two neutron energies (14.1 MeV and 1 MeV) were the primary case studies compared side-by-side.
Throwing an asteroid off course
Not just any nuclear bomb will do when it comes to deflecting incoming asteroids, a new study by Lawrence Livermore reveals — and the differences aren’t just about power. Picking the right bomb is important to getting the asteroid to go in the desired direction, and neutron energy is key.
We now know the Earth is safe from the asteroid Apophis for the rest of the century, removing one short-term danger from space, but sooner or later another space rock will threaten the planet. Many approaches have been suggested to deal with this threat, but nuclear weapons are the most effective proposed so far.
In the event an asteroid or comet is on a collision course with Earth, the appropriate response will vary depending on several factors, most importantly time available. Those who have considered the problem have generally agreed that with enough warning, the best solution is to change the asteroid’s orbit. "Over time, with many years prior to impact, even a miniscule velocity change could add up to an Earth-missing distance," said Air Force Institute of Technology master's student Lansing Horan, who collaborated with LLNL’s Planetary Defense and Weapon Output groups.
Americans used 7 percent less energy in 2020 due in part to the COVID-19 pandemic.
Energy use goes with the flow
Researchers and analysts at Lawrence Livermore National Laboratory (LLNL) released the latest annual flow chart that tracks the production and consumption of energy in the U.S. Overall, the U.S. used 92.9 quads of energy in 2020, a drop of 7.2 quads (7 percent) over the year before.
A quad is a quadrillion BTUs, and 3,412 BTUs is equivalent to a kilowatt hour. The highest recorded energy use in American history was in 2018, when 101.2 quads were consumed.
Despite the large drop in energy use, wind and solar power saw significant gains, with solar up by 19 percent and wind up 10 percent. “Solar and wind continue to show year-on-year growth, which is an impressive change for the energy system,” said A.J. Simon, group leader for Energy at LLNL. “During the pandemic, where total electricity declined only slightly, a lot of coal generation was replaced by renewable energy.”
The pandemic and its associated lockdowns, along with the trend to work from home, led to a 2 percent increase in electricity use in the residential sector. Conversely, transportation energy use fell 14 percent due to the lack of travel during the pandemic.
Elevated carbon dioxide (eCO2) has opposing effects on plant biomass and soil carbon, and these effects contrast between forests and grasslands. Image by Victor O. Leshyk/Center for Ecosystem Science and Society, Northern Arizona University.
Striking pay dirt
Increasing concentrations of carbon dioxide in the atmosphere are boosting the uptake of carbon by plants but may decrease carbon storage in the soil.
An international team, led by Lawrence Livermore National Laboratory, synthesized 108 elevated carbon dioxide (CO2) experiments performed in various ecosystems to find out how much carbon is absorbed by plants and soil.
The terrestrial biosphere takes up about 30 percent of CO2 emitted to the atmosphere by human activities each year. Whether this carbon storage on land can be sustained in the future partly depends on the extent to which elevated CO2 may increase carbon storage in plants and soils. While plant growth often increases in elevated CO2 experiments, individual studies have observed the amount of carbon in the soil can increase, remain unchanged or even decline.
The team found that when plant biomass is strongly stimulated by increased levels of CO2 in the atmosphere, soil carbon storage declines; conversely, where biomass is weakly stimulated, soil carbon accumulates.
Hydrogen gas bubbles evolve from water at a thin layer of gallium oxynitride formed on gallium nitride surfaces. This work demonstrates the chemical transformation of gallium nitride into gallium oxynitride leads to sustained operation and enhanced catalytic activity, thus showing promise for oxynitride layers as protective catalytic coatings for hydrogen evolution. Illustration by Ella Maru Studios.
Creating carbon-free hydrogen fuel
A new artificial photosynthesis device becomes more efficient with each use, and it all has to do with the gallium nitride in the device.
Technologies that turn light and water into carbon-free hydrogen fuel could have unlimited potential, but they have not been developed properly yet. Now, scientists at the University of Michigan, with the help of Lawrence Livermore National Laboratory, have engineered a water-splitting device made with cheap and abundant materials that become more efficient with each use.
The novel device was invented by Zetian Mi, University of Michigan professor of electrical and computer engineering. The device is practically made of an inexpensive semiconductor that is widely used in everyday electronics and has been found to double the efficiency and stability of previous similar technologies.
