Events Video Library

Nuclear power plants generate approximately 16% of the United States' electricity and play a critical role in delivering low-carbon energy. A key challenge in meeting growing energy demands is understanding the long-term behavior of structural materials as plant lifetimes are extended from 40 to 60 years and beyond. Nickel-chromium-based alloys are widely used for their corrosion resistance and mechanical stability at high temperatures. However, these alloys can undergo phase transformations during long-term thermal aging or irradiation, leading to the formation of brittle intermetallic phases. This transformation is associated with reduced ductility and increased brittleness, raising concerns about component reliability. Studying this transformation is challenging because it may take several decades to occur under normal operating conditions. In this work, we accelerate the transformation using irradiation and elevated temperature testing. We also employ atomistic simulations – computational methods that model the behavior of materials at the atomic level – to understand the mechanisms behind phase formation. Together, these approaches enable us to build predictive models of how mechanical properties evolve over time and provide guidance to the industry on component lifetimes.

About Tucker:
Tucker earned her B.S. in Nuclear Engineering from the University of Missouri–Rolla. She attended graduate school at the University of Wisconsin–Madison as a Naval Nuclear Propulsion Fellow, where she received her M.S. and Ph.D. in Nuclear Engineering with a minor in Materials Science in 2008. After graduation, Tucker spent five years as a Principal Scientist at Knolls Atomic Power Laboratory in Schenectady, NY researching welding and the thermal stability of structural alloys for nuclear power systems. She joined the School of Mechanical, Industrial, and Manufacturing Engineering at Oregon State University as an Assistant Professor in 2013 and was promoted to Associate Professor in 2019 and Full Professor in 2023. From 2019 to 2024, Tucker served as the Materials Science Interdisciplinary Graduate Program Director. In 2024, she was appointed the Academic Director for the Design for Social Impact Program.  Tucker has an active research group focused on degradation of materials in extreme environments and alloy development. Her research efforts leverage both modeling and experimental approaches to gain fundamental understanding of materials performance.

Society is facing a series of convergent environmental tragedies, like the collapse in biodiversity, human-caused climate change, the rapid accumulation of waste plastics in waterways and oceans, and more. These challenges will require a diversity of interdisciplinary technologies to be developed and deployed at exceptionally fast rates to market. We have a history of these types of accomplishments, and we can do it again.

In this presentation, I will summarize my recent efforts to create new plastic recycling technologies, since the only free-market approach to combat the plastics problem is to make recycling technologies profitable. The term ‘upcycling’ has gained recent media attention as an attractive means to manage plastic waste, with one key problem: Few technologies exist capable of producing ‘high-value’ products from plastic waste. I will present two plastic recycling approaches. The first combines chemistry and biology capable of depolymerizing mixed plastic waste, like polyethylene terephthalate (PET), polyethylene (PE), and polystyrene (PS), and funneling these compounds into a single product, like a biopolymer or a precursor for nylon product, using an engineered microbe. The second approach uses tandem synergistic chemistry — alkane dehydrogenation and olefin metathesis — to depolymerize polyolefin polymers at temperatures below 200 °C using abundant alkane co-reactants and robust heterogeneous catalysts.

Per- and polyfluoroalkyl substances (PFAS) have impacted drinking water sources in the US and across the globe, resulting in human exposure to PFAS. Understanding the various sources of PFAS within watersheds is a current challenge. Forensics becomes important when seeking remedial strategies or compensation for adverse chemical impacts to properties and human populations, such as those associated with PFAS. While the discipline of environmental forensics is well developed for some classes of contaminants, the environmental forensics of PFAS is in its nascent stage. Chemical ‘fingerprints’ measured by high-resolution mass spectrometry are key to characterizing PFAS sources. Known PFAS sources characterized for this project include groundwater impacted by aqueous film forming foams (AFFF), biosolids leachate, landfill leachates, and various wastewater treatment plant effluents, including those from municipalities and industries. The first step was to determine the chemical fingerprint of each of these sources. The second step was to couple the high- resolution datasets with advanced machine learning to differentiate PFAS sources that can impact surface waters within a watershed. The next steps toward the development of environmental PFAS forensics will also be discussed.

One of the biggest sources of uncertainty in projecting sea level rise is accurately predicting tidewater glacier melt rates. Despite observing glaciers retreating, very few observations of glacier melt rates exist. Observations of tidewater glacier melt made previously using remote sensing suggested that the leading predictive models are underestimating melt by a factor of 10 to 100. This means we still don’t have a great idea of what controls glacier melt rates. Why? Because it is hugely challenging to make underwater measurements of processes that control melt at the face of an actively calving tidewater glacier terminus.

Yet, our collaborative and innovative team have ideas about why glaciers may be melting faster than the prevalent models predict. This includes interesting physics of buoyant melt plume convection, rough ice surfaces, and bubbles popping out of the ice (that not only make sound, but also cause the ice to melt faster). We are making extremely important, and at times scary (no humans in harm’s way) measurements of ice melt and of the processes that control melt at the terminus of Xeitl Sít’ (also known as LeConte Glacier) in Southeast Alaska. Never-before-made measurements are collected from robotic platforms that can travel right to the ice-ocean interface.

Join me to hear about glacier retreat, the processes we think may be important for melt at the ice-ocean interface, the way we are making insightful new measurements, and what we have learned so far to deduce the source of the missing melt.

American farmers currently face numerous challenges, one of the largest being increasing uncertainty about the future availability of farm workers. Despite decades of research, there has been little commercial adoption of robots that can do physically strenuous tasks like pruning, thinning, and harvesting fresh fruits and vegetables. Why? Because biological systems such as orchards and vineyards are really challenging environments for robots. Much of the prior work has focused primarily on visual perception, often ignoring the complex physical interactions that occur when people manipulate plants. In this talk, I’ll discuss ongoing work at Oregon State University to create robots that use novel mechanical devices and sensors to manipulate plants. I’ll also present recent results from an industry-sponsored project to reduce the over-application of fertilizer. Finally, I’ll discuss how our work has expanded to include international collaborations with Europe and Asia as well as a new partnership with a nonprofit to develop assistive technologies to help farm workers.

Headwater streams are essential habitat and provide clean water to downstream users. Their federal protection depends upon their connectivity to downstream waters, which is changing in response to climate and weather patterns. In this talk, I review both the science and policy that govern headwater stream protections. In particular, I highlight a 70+ year study at the HJ Andrews Experimental Forest (near Blue River, Oregon in the Cascade Range) to document the changing flows, connectivity, and protections that could be anticipated in the coming decades.

With increasing water shortages, many agricultural producers are looking to reclaimed water for irrigation.

This lecture discusses a study that explores the feasibility of a new process called electrodialysis-forward osmosis. The goal of the research was to recover nutrients and clean water from anaerobic digester effluent and to safely use it to help grow food crops, specifically lettuce and kale, through hydroponic production.

Impressively, the treatment achieved high nutrient recovery rates and reclaimed up to 74% of clean water. Additionally, the hybrid ED-FO process captured 76-98% of heavy metals and 83% of total organic carbon in the residual waste stream.

Both ED and FO demonstrated low-fouling potential. The economic analysis indicated that the hybrid ED-FO process is promising for scalable implementation, making it highly attractive in terms of resource recovery, waste footprint reduction, and water quality enhancement.

Conservation practices often involve using nature-based solutions on watershed landscapes to solve complex water management problems. These problems can include things like determining how to share water, keeping water clean, dealing with floods and droughts, and adapting to the changing climate.

Practices such as wetlands, grassy areas next to streams, and riparian buffers are implemented on different areas of the landscape and can help make our water cleaner by reducing the transport of nutrients, pesticides, and pathogens from flowing into rivers and lakes downstream. These practices also simultaneously create homes for wildlife and can help lessen the impact of floods and droughts in an area.

But planning for these conservation practices isn't simple. There are many unknowns to consider, like the natural environment, nearby buildings and roads, and how people behave. When engineers or technologists work on solutions for conservation, they need to make sure stakeholders understand the uncertainties involved.

However, many people who are affected by these conservation decisions might not fully understand or might ignore the information about uncertainties. Therefore, it's important to show these uncertainties in a way that's easy for everyone to understand. This helps make sure that decisions about conservation are made in timely and effective ways.

This presentation provides insight into how creating visualizations of the uncertainties around these efforts can impact how people in watershed communities make decisions regarding actions aimed at reducing flooding.

When thinking about water quality, many people probably think about individual pesticides or antibiotics that they heard about in the news. The truth is, there are hundreds, likely millions, of chemicals present in most surface water samples. These chemicals might seem like a random assortment of molecules, but they are a chemical record, or a receipt, of all the biological, chemical, and physical processes that are occurring within a system. When people disturb the land, it leaves a chemical signature in the water. When salmon spawn in the rivers, it leaves a chemical signature in the water. Whether processes occur on land or in the water, our surface waters are libraries of chemical information. If we can decode the chemical signatures in a water sample, we can theoretically collect data on anything and everything that occurs upstream. The challenge is decoding the chemical signatures present. This work has implications for understanding human and ecosystem health and provides a glimpse into how nature will respond to climate change.

The presentation will discuss Managed Aquifer Recharge (MAR) as a crucial tool for managing water resources in the face of climate change. It highlights drywells as a promising solution to overcome challenges associated with traditional MAR techniques. Drywells offer efficient groundwater recharge over a large area, bypassing surface obstacles and minimizing water loss. They present a cost-effective and sustainable approach to address water scarcity and enhance water resilience in diverse environments.