Carbon under pressure exhibits some interesting traits

August 7, 2013

High pressures and temperatures cause materials to exhibit unusual properties, some of which can be special. Understanding such new properties is important for developing new materials for desired industrial uses and also for understanding the interior of Earth, where everything is hot and squeezed.

A paper in Nature Geoscience highlights a new technique in which small amounts of a sample can be studied while being hot and squeezed within an electron microscope. Use of such a microscopy method permits determination of details down to the scale of a few atoms, including the detection of unexpected atom types or atoms in unexpected places, as within a mineral. carbon Download Full Image

Jun Wu and Peter Buseck, the paper’s authors, both at Arizona State University, conducted the research on campus at the J.M. Cowley Center for High Resolution Electron Microscopy of the LeRoy Eyring Center for Solid State Science in ASU's College of Liberal Arts and Sciences. The researchers used tiny containers of carbon, less than one-thousandth the width of a human hair and therefore small enough to fit within high-resolution electron microscopes, to enclose materials similar to those deep within Earth. They then used the electron beam to shrink and thereby squeeze these minuscule capsules. When combined with heating of the samples, new features were observed in the enclosed materials.

“Under such high pressures and temperatures, the materials inside the capsules developed faults that concentrated carbon along them,” explains Buseck, Regents' Professor in the Department of Chemistry and Biochemistry and the School of Earth and Space Exploration.

The Nature Geoscience paper describes the use of this new method to address the important problem of how and where carbon is located within Earth’s interior. Carbon is an essential building block for all forms of life and it also has important effects on climate and climate change through greenhouses gases such as carbon dioxide and carbon tetrahydride, also known as natural gas, or methane.

The largest single reservoir for carbon is within Earth’s interior. However, the known hosts for this carbon are believed to be insufficient to explain the amounts present.

Because Earth’s interior (as well as the interiors of other planets) contains vast amounts of materials like those used in the experiments, the scientists conclude that such faults, and the carbon they concentrate, provide a solution to the problem of explaining where large amounts of carbon reside in Earth’s interior.

Wu and Buseck’s experiments also demonstrate a new way of studying materials at high pressure and temperature within an electron microscope, thereby significantly extending the tools available to scientists for examining materials under extreme conditions.

Nikki Cassis

marketing and communications director, School of Earth and Space Exploration

Making the world a better place, one city at a time

August 7, 2013

Located in the western outskirts of Phoenix, Avondale is quickly becoming an urban destination with over 78,000 residents. How can a growing population sustain the city’s resources into the future?

For the first time, Avondale is developing its very own sustainability plan, and Arizona State University School of Sustainability alum Daniel Culotta is at the helm. headshot of male Daniel Culotta wearing green t-shirt with brown hair and eyes Download Full Image

Culotta graduated from the school last year with a master of arts in sustainability. He is now the environmental program manager for the City of Avondale.

In addition to securing compliance for environmental regulations, Culotta is working with a team of officials to create an organization-wide municipal plan that focuses on a wide variety of areas, including community engagement, energy, ecosystems, health and well-being, land use and the economy.

“We’re creating the sustainability plan using an up-to-date, participatory and evidence-based approach,” Culotta says. “This plan will serve as the foundation for action going forward.”

A native of Jacksonville, Texas, Culotta was an anthropology undergraduate at the University of Texas-Austin before he settled in the environmental consulting field. He advised on human-environment interactions and systems, which led to his epiphany: sustainability is not just about the environment.

“It’s really our relationship with the environment that is the crux of our current challenges,” he says. “The natural resource and endangered species projects I worked on as a consultant often affected more than a single area; they went into the social, cultural and economic sectors of a region, not to mention a broader system of environmental issues.”

Culotta wanted to investigate these systems and interactions further, and the school’s all-encompassing approach to sustainability appealed to him.

“I was also considering the sustainable design program at University of Texas-Austin, but these other programs only focused on a few specific aspects of sustainability,” he says. “ASU on the other hand, has a huge number of well-known scholars and core sustainability faculty. The range of topics for graduate students is also broader.”

Culotta learned about the Avondale position from the school’s Career Services. He says the school prepared him for a fast-paced government position that requires time management, creativity, cooperation and action.

“The School of Sustainability really focuses on sustainability solutions,” he says. “Students are not just gathering information, but actually creating outcomes, which is also a requirement in the workforce.”

Culotta hopes his experience as the Environmental Program Manager for Avondale will help him show that sustainability is not a “nice to have,” but a “need to have.”

“To me, there’s nothing more important than tackling sustainability challenges because they involve all aspects of our society,” he says. “How we deal with them has profound implications for the future of our society and the planet. I hope everything I do in my career helps make the world a better place.”