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 Avalanches (4)
 Plasticity (2)
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 Scaling behavior (2)

 Electronic structure (1)
 Mean field (1)
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 Granular materials (1)
 Deformation (1)
 COSY (1)
 Criticality (1)
 Atmospheric hydrates (1)
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 Classical physics (1)
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 Aerosols (1)
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 Granular materials Bulk metallic glasses (1)
Articles 1  19 of 19
FullText Articles in Physics
Why The Crackling Deformations Of Single Crystals, Metallic Glasses, Rock, Granular Materials, And The Earth’S Crust Are So Surprisingly Similar, Karin A. Dahmen, Jonathan T. Uhl, Wendelin J. Wright
Why The Crackling Deformations Of Single Crystals, Metallic Glasses, Rock, Granular Materials, And The Earth’S Crust Are So Surprisingly Similar, Karin A. Dahmen, Jonathan T. Uhl, Wendelin J. Wright
Faculty Journal Articles
Recent experiments show that the deformation properties of a wide range of solid materials are surprisingly similar. When slowly pushed, they deform via intermittent slips, similar to earthquakes. The statistics of these slips agree across vastly different structures and scales. A simple analytical model explains why this is the case. The model also predicts which statistical quantities are independent of the microscopic details (i.e., they are "universal"), and which ones are not. The model provides physical intuition for the deformation mechanism and new ways to organize experimental data. It also shows how to transfer results from one scale to ...
From Critical Behavior To Catastrophic Runaways: Comparing Sheared Granular Materials With Bulk Metallic Glasses, Alan A. Long, Dmitry Denisov, Peter Schall, Todd C. Hufnagel, Xiaojun Gu, Wendelin J. Wright, Karin A. Dahmen
From Critical Behavior To Catastrophic Runaways: Comparing Sheared Granular Materials With Bulk Metallic Glasses, Alan A. Long, Dmitry Denisov, Peter Schall, Todd C. Hufnagel, Xiaojun Gu, Wendelin J. Wright, Karin A. Dahmen
Faculty Journal Articles
The flow of granular materials and metallic glasses is governed by strongly correlated, avalanchelike deformation. Recent comparisons focused on the scaling regimes of the small avalanches, where strong similarities were found in the two systems. Here, we investigate the regime of large avalanches by computing the temporal profile or “shape” of each one, i.e., the time derivative of the stresstime series during each avalanche. We then compare the experimental statistics and dynamics of these shapes in granular media and bulk metallic glasses. We complement the experiments with a meanfield model that predicts a critical size beyond which avalanches turn ...
Force Oscillations Distort Avalanche Shapes, Louis W. Mcfaul, Wendelin J. Wright, Jordan Sickle, Karin A. Dahmen
Force Oscillations Distort Avalanche Shapes, Louis W. Mcfaul, Wendelin J. Wright, Jordan Sickle, Karin A. Dahmen
Faculty Journal Articles
Contradictory scaling behavior in experiments testing the principle of universality may be due to external oscillations. Thus, the effect of damped oscillatory external forces on slip avalanches in slowly deformed solids is simulated using a meanfield model. Akin to a resonance effect, oscillatory driving forces change the dynamics of avalanches with durations close to the oscillation period. This problem can be avoided by tuning mechanical resonance frequencies away from the range of the inverse avalanche durations. The results provide critical guidance for experimental tests for universality and a quantitative understanding of avalanche dynamics under a wide range of driving conditions.
Aftershocks In Slowly Compressed Bulk Metallic Glasses: Experiments And Theory, Louis W. Mcfaul, Wendelin Wright, Xiaojun Gu, Jonathan T. Uhl, Karin A. Dahmen
Aftershocks In Slowly Compressed Bulk Metallic Glasses: Experiments And Theory, Louis W. Mcfaul, Wendelin Wright, Xiaojun Gu, Jonathan T. Uhl, Karin A. Dahmen
Faculty Journal Articles
We observe two distinct interevent time patterns in the slip avalanches of compressed bulk metallic glasses (BMGs). Small slip avalanches cluster together in time, but large slip avalanches recur roughly periodically. We compare the timing patterns of BMG slip avalanches with timing patterns of earthquakes and with the predictions of a meanfield model. The time clustering of small avalanches is similar to the known time clustering of earthquake foreshocks and aftershocks.
Planar Granular Shear Flow Under External Vibration, Brian Utter, Eric P. Hoppmann
Planar Granular Shear Flow Under External Vibration, Brian Utter, Eric P. Hoppmann
Faculty Journal Articles
We present results from a planar shear experiment in which a twodimensional horizontal granular assembly of pentagonal particles sheared between two parallel walls is subjected to external vibration. Particle tracking and photoelastic measurements are used to quantify both grain scale motion and interparticle stresses with and without imposed vibrations. We characterize the particle motion in planar shear and find that flow of these strongly interlocking particles consists of transient vortex motion with a mean flow given by the sum of exponential profiles imposed by the shearing walls. Vibration is applied either through the shearing surface or as bulk vertical vibration ...
Universal Slip Dynamics In Metallic Glasses And Granular Matter – Linking Frictional Weakening With Inertial Effects, Dmitri V. Denisov, Kinga A. Lorincz, Wendelin J. Wright, Todd C. Hufnagel, Aya Nawano, Xiaojun Gu, Jonathan T. Uhl, Karin A. Dahmen, Peter Schall
Universal Slip Dynamics In Metallic Glasses And Granular Matter – Linking Frictional Weakening With Inertial Effects, Dmitri V. Denisov, Kinga A. Lorincz, Wendelin J. Wright, Todd C. Hufnagel, Aya Nawano, Xiaojun Gu, Jonathan T. Uhl, Karin A. Dahmen, Peter Schall
Faculty Journal Articles
Slowly strained solids deform via intermittent slips that exhibit a materialindependent critical size distribution. Here, by comparing two disparate systems  granular materials and bulk metallic glasses  we show evidence that not only the statistics of slips but also their dynamics are remarkably similar, i.e. independent of the microscopic details of the material. By resolving and comparing the full time evolution of avalanches in bulk metallic glasses and granular materials, we uncover a regime of universal deformation dynamics. We experimentally verify the predicted universal scaling functions for the dynamics of individual avalanches in both systems, and show that both the ...
Manifestations Of Classical Physics In The Quantum Evolution Of Correlated Spin States In Pulsed Nmr Experiments, Martin K. Ligare
Manifestations Of Classical Physics In The Quantum Evolution Of Correlated Spin States In Pulsed Nmr Experiments, Martin K. Ligare
Faculty Journal Articles
Multiplepulse NMR experiments are a powerful tool for the investigation of mole cules with coupled nuclear spins. The product operator formalism provides a way to understand the quantum evolution of an ensemble of weakly coupled spins in such experiments using some of the more intuitive concepts of classical physics and semi classical vector representations. In this paper I present a new way in which to inter pret the quantum evolution of an ensemble of spins. I recast the quantum problem in terms of mixtures of pure states of two spins whose expectation values evolve identi cally to those of classical ...
Avalanche Statistics From Data With Low Time Resolution, Michael Leblanc, Aya Nawano, Wendelin J. Wright, Xiaojun Gu, Jonathan T. Uhl, Karin A. Dahmen
Avalanche Statistics From Data With Low Time Resolution, Michael Leblanc, Aya Nawano, Wendelin J. Wright, Xiaojun Gu, Jonathan T. Uhl, Karin A. Dahmen
Faculty Journal Articles
Extracting avalanche distributions from experimental microplasticity data can be hampered by limited time resolution. We compute the effects of low time resolution on avalanche size distributions and give quantitative criteria for diagnosing and circumventing problems associated with low time resolution. We show that traditional analysis of data obtained at low acquisition rates can lead to avalanche size distributions with incorrect powerlaw exponents or no powerlaw scaling at all. Furthermore, we demonstrate that it can lead to apparent data collapses with incorrect powerlaw and cutoff exponents. We propose new methods to analyze lowresolution stresstime series that can recover the size distribution ...
Concerted HydrogenBond Breaking By Quantum Tunneling In The Water Hexamer Prism, Jeremy O. Richardson, Cristobal Perez, Simon Lobsiger, Adam A. Reid, Berhane Temelso, George C. Shields, Zbigniew Kisiel, David J. Wales, Brooks H. Pate, Stuart C. Althorpe
Concerted HydrogenBond Breaking By Quantum Tunneling In The Water Hexamer Prism, Jeremy O. Richardson, Cristobal Perez, Simon Lobsiger, Adam A. Reid, Berhane Temelso, George C. Shields, Zbigniew Kisiel, David J. Wales, Brooks H. Pate, Stuart C. Althorpe
Faculty Journal Articles
The nature of the intermolecular forces between water molecules is the same in small hydrogenbonded clusters as in the bulk. The rotational spectra of the clusters therefore give insight into the intermolecular forces present in liquid water and ice. The water hexamer is the smallest water cluster to support lowenergy structures with branched threedimensional
hydrogenbond networks, rather than cyclic twodimensional topologies. Here we report measurements of splitting patterns in rotational transitions of the water hexamer prism, and we used quantum simulations to show that they result from geared and antigeared rotations of a pair of water molecules. Unlike previously reported ...
Hydration Of The Sulfuric Acid−Methylamine Complex And Implications For Aerosol Formation, Danielle J. Bustos, Berhane Temelso, George C. Shields
Hydration Of The Sulfuric Acid−Methylamine Complex And Implications For Aerosol Formation, Danielle J. Bustos, Berhane Temelso, George C. Shields
Faculty Journal Articles
The binary H_{2}SO_{4}−H_{2}O nucleation is one of the most important pathways by which aerosols form in the atmosphere, and the presence of ternary species like amines increases aerosol formation rates. In this study, we focus on the hydration of a ternary system of sulfuric acid (H_{2}SO_{4}), methylamine (NH_{2}CH_{3}), and up to six waters to evaluate its implications for aerosol formation. By combining molecular dynamics (MD) sampling with highlevel ab initio calculations, we determine the thermodynamics of forming H_{2}SO_{4}(NH_{2}CH_{3})(H_{2}O ...
Computational Study Of The Hydration Of Sulfuric Acid Dimers: Implications For Acid Dissociation And Aerosol Formation, Berhane Temelso, Thuong Ngoc Phan, George C. Shields
Computational Study Of The Hydration Of Sulfuric Acid Dimers: Implications For Acid Dissociation And Aerosol Formation, Berhane Temelso, Thuong Ngoc Phan, George C. Shields
Faculty Journal Articles
We have investigated the thermodynamics of sulfuric acid dimer hydration using ab initio quantum mechanical methods. For (H_{2}SO_{4})_{2}(H_{2}O)_{n} where n = 0−6, we employed highlevel ab initio calculations to locate the most stable minima for each cluster size. The results presented herein yield a detailed understanding of the first deprotonation of sulfuric acid as a function of temperature for a system consisting of two sulfuric acid molecules and up to six waters. At 0 K, a cluster of two sulfuric acid molecules and one water remains undissociated. Addition of a second water ...
A Remotely Interrogated AllOptical Rb87 Magnetometer, B. Patton, O. O. Versolato, D. C. Hovde, E. Corsini, James M. Higbie, D. Budker
A Remotely Interrogated AllOptical Rb87 Magnetometer, B. Patton, O. O. Versolato, D. C. Hovde, E. Corsini, James M. Higbie, D. Budker
Faculty Journal Articles
Atomic magnetometry was performed at Earth's magnetic field over a freespace distance of ten meters. Two laser beams aimed at a distant alkalivapor cell excited and detected the Rb87 magnetic resonance, allowing the magnetic field within the cell to be interrogated remotely. Operated as a driven oscillator, the magnetometer measured the geomagnetic field with less than or similar to 3.5 pT precision in a similar to 2 s data acquisition; this precision was likely limited by ambient field fluctuations. The sensor was also operated in selfoscillating mode with a 5.3 pT root Hz noise floor. Further optimization ...
Barriers To Front Propagation In Ordered And Disordered Vortex Flows, Dylan Bargteil, Tom Solomon
Barriers To Front Propagation In Ordered And Disordered Vortex Flows, Dylan Bargteil, Tom Solomon
Faculty Journal Articles
We present experiments on reactive front propagation in a twodimensional (2D) vortex chain flow (both timeindependent and timeperiodic) and a 2D spatially disordered (timeindependent) vortexdominated flow. The flows are generated using magnetohydrodynamic forcing techniques, and the fronts are produced using the excitable, ferroincatalyzed BelousovZhabotinsky chemical reaction. In both of these flows, front propagation is dominated by the presence of burning invariant manifolds (BIMs) that act as barriers, similar to invariant manifolds that dominate the transport of passive impurities. Convergence of the fronts onto these BIMs is shown experimentally for all of the flows studied. The BIMs are also shown to ...
Search For Plant Biomagnetism With A Sensitive Atomic Magnetometer, Eric Corsini, Victor Acosta, Nicolas Baddour, James M. Higbie, Brian Lester, Paul Licht, Brian Patton, Mark Prouty, Dmitry Budke
Search For Plant Biomagnetism With A Sensitive Atomic Magnetometer, Eric Corsini, Victor Acosta, Nicolas Baddour, James M. Higbie, Brian Lester, Paul Licht, Brian Patton, Mark Prouty, Dmitry Budke
Faculty Journal Articles
No abstract provided.
Hydrodynamic Correlation Functions Of A Driven Granular Fluid In Steady State, Katharina VollmayrLee, Timo Aspelmeier, Annette Zippelius
Hydrodynamic Correlation Functions Of A Driven Granular Fluid In Steady State, Katharina VollmayrLee, Timo Aspelmeier, Annette Zippelius
Faculty Journal Articles
No abstract provided.
Discovery Of A Young L Dwarf Binary, Sdss224953.47+004404.6ab, Katelyn N. Allers, Michael C. Liu, Trent J. Dupuy, Michael C. Cushing
Discovery Of A Young L Dwarf Binary, Sdss224953.47+004404.6ab, Katelyn N. Allers, Michael C. Liu, Trent J. Dupuy, Michael C. Cushing
Faculty Journal Articles
No abstract provided.
Classical Thermodynamics Of Particles In Harmonic Traps, Martin K. Ligare
Classical Thermodynamics Of Particles In Harmonic Traps, Martin K. Ligare
Faculty Journal Articles
No abstract provided.
Optimization Of Cw Sodium Laser Guide Star Efficiency, R. Holzlöhner, S. M. Rochester, D. Bonaccini Calia, D. Budker, James M. Higbie, W. Hackenberg
Optimization Of Cw Sodium Laser Guide Star Efficiency, R. Holzlöhner, S. M. Rochester, D. Bonaccini Calia, D. Budker, James M. Higbie, W. Hackenberg
Faculty Journal Articles
No abstract provided.
Aging To Equilibrium Dynamics Of Sio2, Katharina VollmayrLee, J. A. Roman, J. Horbach
Aging To Equilibrium Dynamics Of Sio2, Katharina VollmayrLee, J. A. Roman, J. Horbach
Faculty Journal Articles
No abstract provided.