C.R.A.M. Lab @ M.H.C.
Complex Rheology And Many-body systems at Mount Holyoke College
Prof. Kerstin Nordstrom, Principal Investigator
2021 updates: Casey Roepke graduates, new paper published in Granular Matter, Prof. Nordstrom awarded tenure (in 2020)
May 2020: Linda Zhang and Keelin Quirk defend their theses and graduate summa cum laude! CONGRATULATIONS!
About The Lab:
We are interested in understanding the flow behavior ("rheology") of materials made up of lots of discrete objects ("many-body"). A common example of a material like this is sand: the objects that make up the bulk material are the solid grains. Another example is mayonnaise, which is mostly made of tiny oil droplets crowded together. The crowded nature of these systems gives rise to interesting bulk behaviors such as jamming, avalanching, and non-Newtonian rheology.
Our big question: how do interactions and motions at the particle scale give rise to bulk behavior?
We study a variety of these systems (grains, colloids, swimming cells, and robot swarms) experimentally to tackle this question. Our primary data is high speed video. From this we use image processing algorithms to identify and track particles. A single experiment will yield position+time data for thousands of particles in thousands of frames! From these tracks we can look at the flow field, fluctuations from the average flow, and many other higher-level metrics.
We also run complementary simulations using the LAMMPS molecular dynamics code. These simulations allow finer control of our conditions, allow us to explore unusual situations (such as reduced gravity), and give us information about the forces the particles experience (not possible with experimental particle tracking).
Experimentally, when our systems are small, we use microfluidic channels to image the flows. Some of these channels are fabricated in-house. We are always interested in developing novel ways to fabricate channels, and can help other groups on campus (or nearby) design and fabricate MEMS devices.
Our YouTube channel can give you a sense of some of the things we are thinking about.
For more detailed explanations of our current projects, click here.