Gain fundamental knowledge on the properties of liquid water at interfaces using molecular dynamics (MD) simulations, macroscopic scale models, and laboratory experiments in order to improve representations of key environmental processes.
Ian C. Bourg
Assistant Professor of Civil and Environmental Engineering and the High Meadows Environmental Institute
Mentor
Avery Agles
PhD Student
Mentor
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BACKGROUND
Freshwater has become increasingly scarce and unpredictable
Biofilms play a fundamental role within soil ecosystems
Drought protection, nutrient retention, carbon source, signaling, symbiosis with plants
Extracellular Polymeric Substance (EPS) account for 50-90% of biofilm matrix
Hypothesized that the presence of both biofilms and clay would lead to synergistic dynamics that have implications for water transport and retention
The hierarchical model of soil aggregate classification. "Microbial Extracellular Polymeric Substances: Ecological Function and Impact on Soil Aggregation," O. Y. Costa, J. M. Raaijmakers, E. E. Kuramae (2018)
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INTERNSHIP
Goal:
Create a system of a droplet of water containing alginate on a surface representing the biofilm matrix.
Apply a force to the droplet to study the dynamic wetting of a given surface.
Supplemental tasks:
Learned how to utilize GROMACS, an open-source software the simulates Newtonian equations of motion for systems with hundreds to millions of atoms
Read relative literature on the research surrounding topic
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SYSTEM
Slab of pyrophyllite as surface
Pyrophyllite is a charge neutral surface and is being used as a proxy for clay
Modeled pyrophyllite slab using Thomas Underwood’s tutorial on pyrophyllite
Restrained position of surface
10nmx10nmx10nm box of water with alginate and ions to balance charge. Representative of biofilm with 95% water
System utilizes its periodic image to form an infinite image in the x-direction so that I could focus on its 2-D shape
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NON-EQUILIBRIUM MOLECULAR DYNAMICS
Accelerate droplet and its contents
Past Acceleration: 0.01 nm/ps2
Equivalent to 1 x 1013 m/s2
Current Acceleration: 0.001 nm/ps2
Equivalent to 1 X 1012 m/s2
Acceleration can be viewed as being analogous with gravity
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FUTURE PLANS
Analyze
Analyze further data
Measure
Measure contact angle
Find
Find optimal range of acceleration
Fix
Fix alginate-surface attachment
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SOURCES
Donlan, R. M. (2002). Biofilms: Microbial life on surfaces. Emerging Infectious Diseases,8(9), 881-890. doi:10.3201/eid0809.020063
Costa, O. Y., Raaijmakers, J. M., & Kuramae, E. E. (2018). Microbial extracellular polymeric substances: Ecological function and impact on soil aggregation. Frontiers in Microbiology,9. doi:10.3389/fmicb.2018.01636