302 citations · 1.5k across the 32 of their papers we have counts for
32 papers
Dynamics of Reversible Plasticity in an Amorphous Solid
Zhicheng Wang, Nathan C. Keim
Local rearrangements are the elements of plastic deformation in an amorphous solid. In oscillatory shear, they can switch reversibly between two distinct configurations. While thes…
The mechanical latching memory of an adhesive tape
Sebanti Chattopadhyay, Carys Chase-Mayoral, Nathan Keim
The storage and retrieval of mechanical imprints from past perturbations is a central theme in soft matter physics. Here we study this effect in the partial peeling of an ordinary…
Memories of amplitude and direction coexist and compete in non-Brownian suspensions
Surendra Padamata, Nathan C. Keim
Steadily shearing a non-Brownian suspension forms a memory of direction, while shearing back and forth forms a memory of amplitude. Each memory is evident in the systems response t…
Ordered buckling structures in a twisted crimped tube
Pan Dong, Nathan C. Keim, Joseph D. Paulsen
When a ribbon or tube is twisted far enough it forms buckles and wrinkles. Its new geometry can be strikingly ordered, or hopelessly disordered. Here we study this process in a tub…
Mechanical memories in solids, from disorder to design
Joseph D. Paulsen, Nathan C. Keim
Solids are rigid, which means that when left undisturbed, their structures are nearly static. It follows that these structures depend on history -- but it is surprising that they h…
Generalizing multiple memories from a single drive: The hysteron latch
Chloe W. Lindeman, Travis R. Jalowiec, Nathan C. Keim
Far-from-equilibrium systems can form memories of previous deformations or driving. In systems from sheared glassy materials to buckling beams to crumpled sheets, this behavior is…
A wrinkled cylindrical shell as a tunable locking material
Pan Dong, Mengfei He, Nathan C. Keim +1
A buckled sheet offers a reservoir of material that can be unfurled at a later time. For sufficiently thin yet stiff materials, this geometric process has a striking mechanical fea…
Tuning the rheology and microstructure of particle-laden fluid interfaces with Janus particles
Yiming Qiao, Xiaolei Ma, Zhengyang Liu +3
Hypothesis: Particle-laden fluid interfaces are the central component of many natural and engineering systems. Understanding the mechanical properties and improving the stability o…
Mechanical annealing and memories in a disordered solid
Nathan C. Keim, Dani Medina
Shearing a disordered or amorphous solid for many cycles with a constant strain amplitude can anneal it, relaxing a sample to a steady state that encodes a memory of that amplitude…
Scaling of relaxation and excess entropy in plastically deformed amorphous solids
K. L. Galloway, Xiaoguang Ma, Nathan C. Keim +3
When stressed sufficiently, solid materials yield and deform plastically via reorganization of microscopic constituents. Indeed, it is possible to alter the micro-structure of mate…
Relationships among structure, memory, and flow in sheared disordered materials
K. L. Galloway, E. G. Teich, X-g Ma +7
A fundamental challenge for disordered solids is predicting macroscopic yield from the microscopic arrangements of constituent particles. Yield is accompanied by a sudden and large…
Multiperiodic orbits from interacting soft spots in cyclically-sheared amorphous solids
Nathan C. Keim, Joseph D. Paulsen
When an amorphous solid is deformed cyclically, it may reach a steady state in which the paths of constituent particles trace out closed loops that repeat in each driving cycle. A…
Memory formation in matter
Nathan C. Keim, Joseph D. Paulsen, Zorana Zeravcic +2
Memory formation in matter is a theme of broad intellectual relevance; it sits at the interdisciplinary crossroads of physics, biology, chemistry, and computer science. Memory conn…
Minimal descriptions of cyclic memories
Joseph D Paulsen, Nathan C Keim
Many materials that are out of equilibrium can "learn" one or more inputs that are repeatedly applied. Yet, a common framework for understanding such memories is lacking. Here we c…
Global Memory from Local Hysteresis in an Amorphous Solid
Nathan C. Keim, Jacob Hass, Brian Kroger +1
A disordered material that cannot relax to equilibrium, such as an amorphous or glassy solid, responds to deformation in a way that depends on its past. In experiments we train a 2…
Role of disorder in finite-amplitude shear of a 2D jammed material
Nathan C. Keim, Paulo E. Arratia
A material's response to small but finite deformations can reveal the roots of its response to much larger deformations. Here, we identify commonalities in the responses of 2D soft…
Undulatory swimming in shear-thinning fluids: Experiments with C. elegans
David A. Gagnon, Nathan C. Keim, Paulo E. Arratia
The swimming behaviour of microorganisms can be strongly influenced by the rheology of their fluid environment. In this manuscript, we experimentally investigate the effects of she…
Multiple transient memories in experiments on sheared non-Brownian suspensions
Joseph D. Paulsen, Nathan C. Keim, Sidney R. Nagel
A system with multiple transient memories can remember a set of inputs but subsequently forgets almost all of them, even as they are continually applied. If noise is added, the sys…
Fluid-Induced Propulsion of Rigid Particles in Wormlike Micellar Solutions
David A. Gagnon, Nathan C. Keim, Xiaoning Shen +1
In the absence of inertia, a reciprocal swimmer achieves no net motion in a viscous Newtonian fluid. Here, we investigate the ability of a reciprocally actuated particle to transla…
The structure and dynamics of self-assembling colloidal monolayers in oscillating magnetic fields
Alison E. Koser, Nathan C. Keim, Paulo E. Arratia
Many fascinating phenomena such as large-scale collective flows, enhanced fluid mixing and pattern formation have been observed in so-called active fluids, which are composed of pa…
Self-assembling paramagnetic colloids in oscillating magnetic fields
Alison E. Koser, Nathan C. Keim, Paulo E. Arratia
Many fascinating phenomena such as large-scale collective flows, enhanced fluid mixing and pattern formation have been observed in so-called active fluids, which are composed of pa…
Dropping the Ball: The effect of anisotropic granular materials on ejecta and impact crater shape
Philip Drexler, Nathan Keim, Paulo Arratia
In this fluid dynamics video, we present an experimental investigation of the shape of impact craters in granular materials. Complex crater shapes, including polygons, have been ob…
Mechanical and microscopic properties of the reversible plastic regime in a 2D jammed material
Nathan C. Keim, Paulo E. Arratia
At the microscopic level, plastic flow of a jammed, disordered material consists of a series of particle rearrangements that cannot be reversed by subsequent deformation. An infini…
Vibration and Nonlinear Resonance in the Break-up of an Underwater Bubble
Lipeng Lai, Nathan C. Keim, Kamel Fezzaa +2
We use high-speed X-ray phase-contrast imaging, weakly nonlinear analysis and boundary integral simulations to characterize the final stage of underwater bubble break-up. The X-ray…