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New simulations suggest that carbon (C) routinely bonded with iron (Fe), silicon (Si) and oxygen (O) deep within the magma ocean that covered Earth when it was young.

New insights about carbon and ice could clarify inner workings of Earth, other planets

New simulations suggest that carbon (C) routinely bonded with iron (Fe), silicon (Si) and oxygen (O) deep within the magma ocean that covered Earth when it was young.

New simulations suggest that carbon (C) routinely bonded with iron (Fe), silicon (Si) and oxygen (O) deep within the magma ocean that covered Earth when it was young.

 

Most people behave differently when under extreme pressure. Carbon and ice are no different.

Two new studies show how these key planetary ingredients take on exotic forms that could help researchers better understand the composition of Earth’s core as well as the cores of planets across the galaxy. Craig Manning, a UCLA professor of geology and geochemistry, is a co-senior author of one of the papers, which was published today in the journal Nature, and senior author of the other, which was published in Nature Communications in February.

The Nature Communications paper revealed that high pressure deep inside the young Earth may have driven vast stores of carbon into the planet’s core while also setting the stage for diamonds to form. In the Nature report, researchers found that water ice undergoes a complex crystalline metamorphosis as the pressure slowly ratchets up.

Scientists have long understood that the amount of carbon sequestered in present-day Earth’s rocks, oceans and atmosphere is always in flux because the planet shuffles the element around in a vast cycle that helps regulate climate. But researchers don’t know whether the Earth locked away even more carbon deep in its interior during its formative years — information that could reveal a little more about how our planet and others like it are built.

To pursue an answer to that question, Manning and colleagues calculated how carbon might have interacted with other atoms under conditions similar to those that prevailed roughly 4.5 billion years ago, when much of Earth was still molten. Using supercomputers, the team created simulations to explore what would happen to carbon at temperatures above 3,000 degrees Celsius (more than 5,400 degrees Fahrenheit) and at pressures more than 100,000 times of those on Earth’s surface today.

The experiment revealed that under those conditions, carbon tends to link up with iron, which implies that there might be considerable quantities of carbon sealed in Earth’s iron core today. Researchers had already suspected that in the young planet’s magma ocean, iron atoms hooked up with one another and then dropped to the planet’s center. But the new research suggests that this molten iron rain may have also dragged carbon down with it. Until now, researchers weren’t even sure whether carbon exists down there.

The team also found that as the pressure ramps up, carbon increasingly bonds with itself, forming long chains of carbon atoms with oxygen atoms sticking out.

“These complex chains are a form of carbon bonding that we really hadn’t anticipated at these conditions,” Manning said.

Such molecules could be a precursor to diamonds, which consist of many carbon atoms linked together.

Solving an icy enigma

The machinations of carbon under pressure provide clues as to how Earth-like planets are built. Frozen planets and moons in other solar systems, however, may also have to contend with water ice. In a separate paper, Manning and another team of scientists looked at how the molecular structure of extremely cold ice changes when put under intense pressure.

Under everyday conditions, water ice is made up of molecules laid out in honeycomb-like mosaics of hexagons. But when ice is exposed to crushing pressure or very low temperature — in labs or possibly deep inside remote worlds — the molecules can assume a bewildering variety of patterns.

One of those patterns, known as amorphous ice, is an enigma. In amorphous ice, the water molecules eschew rigid crystalline order and take on a free-form arrangement. Manning and colleagues set out to try and understand how amorphous ice forms.

First, they chilled normal ice to about 170 degrees below zero Celsius (about 274 degrees below zero Fahrenheit). Then, they locked the ice in the jaws of a high-tech vice grip inside a cryogenic vacuum chamber. Finally, over the span of several hours, they slowly stepped up the pressure in the chamber to about 15,000 times atmospheric pressure. They stopped raising the pressure periodically to fire neutrons through the ice so that they could see the arrangement of the water molecules.

Surprisingly to the researchers, the amorphous ice never formed. Instead, the molecules went through a series of previously known crystalline arrangements.

However, when the researchers conducted the same experiment but raised the pressure much more rapidly — this time in just 30 minutes — amorphous ice formed as expected. The results suggest that time is the secret ingredient: When pressure increases slowly, tiny seeds of crystalline ice have time to form and take over the sample. Otherwise, those seeds never get a chance to grow.

The findings, published May 23 in the journal Nature, could be useful to researchers who study worlds orbiting other suns and are curious about what conditions might be like deep inside frozen planets.

“It’s entirely likely that there are planets dominated by ice in other solar systems that could obtain these pressures and temperatures with ease,” Manning said. “We have to have this right if we’re going to have a baseline for understanding the interiors of cold worlds that may not be like Earth.”

Both papers were funded in part by the Deep Carbon Observatory, a 10-year program started in 2009 to investigate the quantities, movements, forms and origins of deep carbon inside Earth. The Nature Communications paper was also funded by the European Research Council and was co-authored by researchers at the Ecole Normale Supérieure de Lyon in France, one of whom — Natalia Solomatova — completed her undergraduate studies at UCLA. The Nature paper was co-authored by UCLA geologist Adam Makhluf and researchers from Oak Ridge National Laboratory and the National Research Council of Canada.

This article originally appeared on the UCLA Newsroom.

 

Best in snow: New scientific device creates electricity from snowfall

UCLA researchers and colleagues have designed a new device that creates electricity from falling snow. The first of its kind, this device is inexpensive, small, thin and flexible like a sheet of plastic.

“The device can work in remote areas because it provides its own power and does not need batteries,” said senior author Richard Kaner, who holds UCLA’s Dr. Myung Ki Hong Endowed Chair in Materials Innovation. “It’s a very clever device — a weather station that can tell you how much snow is falling, the direction the snow is falling, and the direction and speed of the wind.”

The researchers call it a snow-based triboelectric nanogenerator, or snow TENG. A triboelectric nanogenerator, which generates charge through static electricity, produces energy from the exchange of electrons.

Findings about the device are published in the journal Nano Energy.

Maher El-Kady and Richard Kaner

Maher El-Kady and Richard Kaner

“Static electricity occurs from the interaction of one material that captures electrons and another that gives up electrons,” said Kaner, who is also a distinguished professor of chemistry and biochemistry, and of materials science and engineering, and a member of the California NanoSystems Institute at UCLA. “You separate the charges and create electricity out of essentially nothing.”

Snow is positively charged and gives up electrons. Silicone — a synthetic rubber-like material that is composed of silicon atoms and oxygen atoms, combined with carbon, hydrogen and other elements — is negatively charged. When falling snow contacts the surface of silicone, that produces a charge that the device captures, creating electricity.

“Snow is already charged, so we thought, why not bring another material with the opposite charge and extract the charge to create electricity?” said co-author Maher El-Kady, a UCLA assistant researcher of chemistry and biochemistry.

“While snow likes to give up electrons, the performance of the device depends on the efficiency of the other material at extracting these electrons,” he added. “After testing a large number of materials including aluminum foils and Teflon, we found that silicone produces more charge than any other material.”

About 30 percent of the Earth’s surface is covered by snow each winter, during which time solar panels often fail to operate, El-Kady noted. The accumulation of snow reduces the amount of sunlight that reaches the solar array, limiting the panels’ power output and rendering them less effective. The new device could be integrated into solar panels to provide a continuous power supply when it snows, he said.

Hiking shoe with device attached

Hiking shoe with device attached

The device can be used for monitoring winter sports, such as skiing, to more precisely assess and improve an athlete’s performance when running, walking or jumping, Kaner said. It also has the potential for identifying the main movement patterns used in cross-country skiing, which cannot be detected with a smart watch.

It could usher in a new generation of self-powered wearable devices for tracking athletes and their performances.

It can also send signals, indicating whether a person is moving. It can tell when a person is walking, running, jumping or marching.

The research team used 3-D printing to design the device, which has a layer of silicone and an electrode to capture the charge. The team believes the device could be produced at low cost given “the ease of fabrication and the availability of silicone,” Kaner said. Silicone is widely used in industry, in products such as lubricants, electrical wire insulation and biomedical implants, and it now has the potential for energy harvesting.

Co-authors include Abdelsalam Ahmed, who conducted the research while completing his doctoral studies at the University of Toronto; Islam Hassan and Ravi Selvaganapathy of Canada’s McMaster University; and James Rusling of the University of Connecticut and his research team.

Kaner’s research was funded by Nanotech Energy, a company spun off from his research (Kaner is chair of its scientific advisory board and El-Kady is chief technology officer); and Kaner’s Dr. Myung Ki Hong Endowed Chair in Materials Innovation.

Kaner’s laboratory has produced numerous devices, including a membrane that separates oil from water and cleans up the debris left by oil fracking. Fracking is a technique to extract gas and oil from shale rock.

Kaner, El-Kady and colleagues designed a device in 2017 that can use solar energy to inexpensively and efficiently create and store energy, which could be used to power electronic devices and to create hydrogen fuel for eco-friendly cars. This year, they published research on their design of the first fire-retardant, self-extinguishing motion sensor and power generator, which could be embedded in shoes or clothing worn by firefighters and others who work in harsh environments.

Kaner is among the world’s most influential and highly cited scientific researchers. He was selected as the recipient of the American Institute of Chemists 2019 Chemical Pioneer Award, which honors chemists and chemical engineers who have made outstanding contributions that advance the science of chemistry or greatly impact the chemical profession.