Growing up in Los Angeles, Viviana Vela grew accustomed to feeling–and thinking about–earthquakes. She even brought that awareness to choosing her field of study: structural engineering, which she pursued first as an undergraduate student at UC San Diego and later at UC Berkeley’s College of Civil and Environmental Engineering where she received her Master’s Degree this spring. Now Vela has just finished up a summer internship at EESA made possible by a prestigious GEM fellowship. It’s an experience she’ll take with her back to southern California as she begins pursuing her Ph.D. in structural/earthquake engineering at UCLA this fall.
We talked with Viviana to discuss her work with EESA research scientist Hang Deng and another scientist on the project Marco Voltolini to investigate the mechanical properties of shale–sedimentary rocks made up largely of fine-grained mineral particles intermixed with organic matter that are prevalent in Earth’s subsurface.
Here’s what she had to say.
Question: What project were you working on this summer at Berkeley Lab and how does it relate to your background?
Answer: As a structural engineer, I’m interested in how resilient structures are to different loading conditions. Often that has to do with a building’s design, but also has to do with the materials being used and their microstructural design. Mostly, I investigate the strength and mechanics of concrete and steel because they are the most commonly used materials in civil design.
The project I worked on this summer with my supervisor Hang Deng looked at the strength and mechanics of shale, a type of sedimentary rock. Although it is a geological material, its porous and inhomogeneous microstructure reminds me of concrete and I was able to translate my background to a more general understanding of porous media. We wanted to characterize its mechanical strength and identify how the mineral makeup of the shale samples we studied influenced those mechanics. Shale rock is prevalent in the Earth’s subsurface, making it of interest to scientists who examine interactions between fluids and subsurface rock that might influence efforts to derive unconventional sources of energy from the Earth’s subsurface.
Question: How will this experience benefit you as you begin your doctoral studies this fall?
Answer: As an undergraduate and graduate student, most of my research work was more on the computational side. In my Ph.D. studies, I am interested in doing more experimental work. Compared to my previous internships, this was the first time I got to run some experiments. As part of the project, some micro-indentation tests were run at the Advanced Light Source (ALS) on a 9.5 millimeter shale sample to measure indentation depth. The way these tests work is that you apply load to the shale using an indenter and then measure the indentation that results from the applied load. From that point, you can take the depth of the indentation at various loading conditions and plot the force vs. indentation depth from which you can extract important parameters needed for determining mechanical properties.
Question: How will your experience as a GEM Fellow influence your future career?
Answer: I was really excited to be offered this opportunity at Berkeley Lab through the GEM program. I learned new tools and techniques that I never knew could be used in experimental work. For example, I had to learn how to process an image from a radiograph and use various radiographs taken at different angles to reconstruct volume information for three dimensional analysis. After image processing and tomographic reconstruction, I was able to extract the indentation information needed to extract mechanical properties and even track fractures during experimentation.
After I finish my Ph.D., I want to become a professor and teach. I think that what I was able to do here this summer at Berkeley Lab will be a huge benefit to teaching students whose careers in science are just getting started.