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Sun Y, Wang C, Yang J, Shi W, Pang Q, Wang Y, Li J, Hu B, Xia C. Evident structural anisotropies arising from near-zero particle asphericity in granular spherocylinder packings. Phys Rev E 2024; 110:014903. [PMID: 39161035 DOI: 10.1103/physreve.110.014903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Accepted: 07/02/2024] [Indexed: 08/21/2024]
Abstract
With magnetic resonance imaging experiments, we study packings of granular spherocylinders with merely 2% asphericity. Evident structural anisotropies across all length scales are identified. Most interestingly, the global nematic order decreases with increasing packing fraction, while the local contact anisotropy shows an opposing trend. We attribute this counterintuitive phenomenon to a competition between gravity-driven ordering aided by frictional contacts and a geometric frustration effect at the marginally jammed state. It is also surprising to notice that such slight particle asphericity can trigger non-negligible correlations between contact-level and mesoscale structures, manifested in drastically different nonaffine structural rearrangements upon compaction from that of granular spheres. These observations can help improve statistical mechanical models for the orientational order transformation of nonspherical granular particle packings, which involves complex interplays between particle shape, frictional contacts, and external force field.
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Affiliation(s)
| | | | | | | | | | - Yujie Wang
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China
- Department of Physics, College of Mathematics and Physics, Chengdu University of Technology, Chengdu 610059, China
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2
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Pan Y, Gong X, Rotta Loria AF. Thermal shakedown in granular materials with irregular particle shapes. Sci Rep 2024; 14:6828. [PMID: 38514723 PMCID: PMC10957884 DOI: 10.1038/s41598-024-57503-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Accepted: 03/19/2024] [Indexed: 03/23/2024] Open
Abstract
Granular materials with irregular particle shapes undergo a myriad of temperature variations in natural and engineered systems. However, the impacts of cyclic temperature variations on the mechanics of granular materials remain poorly understood. Specifically, little is known about the response of granular materials to cyclic temperature variations as a function of the following central variables: particle shape, applied stress level, relative density, and temperature amplitude. This paper presents advanced laboratory experiments to explore the impacts of cyclic temperature variations on the mechanics of granular materials, with a focus on sands. The results show that cyclic temperature variations applied to sands induce thermal shakedown: the accumulation of irreversible bulk deformations due to microstructural rearrangements caused by thermal expansions and contractions of the constituting particles. The deformation of sands caused by thermal shakedown strongly depends on particle shape, stress level, relative density, and temperature amplitude. This deformation is limited for individual thermal cycles but accumulates and becomes significant for multiple thermal cycles, leading to substantial compaction in sands and other granular materials, which can affect various natural and engineered systems.
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Affiliation(s)
- Yize Pan
- Department of Civil and Environmental Engineering, Subsurface Opportunities and Innovations Laboratory, Northwestern University, Evanston, USA
| | - Xiaohui Gong
- Department of Civil and Environmental Engineering, Subsurface Opportunities and Innovations Laboratory, Northwestern University, Evanston, USA
| | - Alessandro F Rotta Loria
- Department of Civil and Environmental Engineering, Subsurface Opportunities and Innovations Laboratory, Northwestern University, Evanston, USA.
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3
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Du X, Weeks ER. Rearrangements during slow compression of a jammed two-dimensional emulsion. Phys Rev E 2024; 109:034605. [PMID: 38632734 DOI: 10.1103/physreve.109.034605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Accepted: 02/20/2024] [Indexed: 04/19/2024]
Abstract
As amorphous materials get jammed, both geometric and dynamic heterogeneity are observed. We investigate the correlation between the local geometric heterogeneity and local rearrangements in a slowly compressed bidisperse quasi-two-dimensional emulsion system. The compression is driven by evaporation of the continuous phase and causes the area packing fraction to increase from 0.88 to 0.99. We quantify the structural heterogeneity of the system using the radical Voronoi tessellation following the method of Rieser et al. [Phys. Rev. Lett. 116, 088001 (2016)]0031-900710.1103/PhysRevLett.116.088001. We define two structural quantities characterizing local structure, the first of which considers nearest neighbors and the second of which includes information from second-nearest neighbors. We find that droplets in heterogeneous local regions are more likely to have local rearrangements. These rearrangements are generally T1 events where two droplets converge toward a void, and two droplets move away from the void to make room for the converging droplets. Thus, the presence of the voids tends to orient the T1 events. The presence of a correlation between the structural quantities and the rearrangement dynamics remains qualitatively unchanged over the entire range of packing fractions observed.
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Affiliation(s)
- Xin Du
- Department of Physics and Astronomy, Widener University, Chester, Pennsylvania 19013, USA
| | - Eric R Weeks
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA
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4
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Born P, Braibanti M, Cristofolini L, Cohen-Addad S, Durian DJ, Egelhaaf SU, Escobedo-Sánchez MA, Höhler R, Karapantsios TD, Langevin D, Liggieri L, Pasquet M, Rio E, Salonen A, Schröter M, Sperl M, Sütterlin R, Zuccolotto-Bernez AB. Soft matter dynamics: A versatile microgravity platform to study dynamics in soft matter. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:124503. [PMID: 34972443 DOI: 10.1063/5.0062946] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 11/23/2021] [Indexed: 06/14/2023]
Abstract
We describe an experiment container with light scattering and imaging diagnostics for experiments on soft matter aboard the International Space Station (ISS). The suite of measurement capabilities can be used to study different materials in exchangeable sample cell units. The currently available sample cell units and future possibilities for foams, granular media, and emulsions are presented in addition to an overview of the design and the diagnostics of the experiment container. First results from measurements performed on ground and during the commissioning aboard the ISS highlight the capabilities of the experiment container to study the different materials.
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Affiliation(s)
- P Born
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany
| | - M Braibanti
- HE Space Operations BV for ESA, NL-2200AG Noordwijk, The Netherlands
| | - L Cristofolini
- CNR - Institute of Condensed Matter Chemistry and Technologies for Energy Unit of Genoa, 16149 Genova, Italy
| | - S Cohen-Addad
- Sorbonne Universités, UPMC Univ Paris 06, CNRS-UMR 7588, Institut des NanoSciences de Paris, 4 place Jussieu, 75005 Paris, France
| | - D J Durian
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - S U Egelhaaf
- Condensed Matter Physics Laboratory, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - M A Escobedo-Sánchez
- Condensed Matter Physics Laboratory, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - R Höhler
- Sorbonne Universités, UPMC Univ Paris 06, CNRS-UMR 7588, Institut des NanoSciences de Paris, 4 place Jussieu, 75005 Paris, France
| | - T D Karapantsios
- Department of Chemical Technology, School of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
| | - D Langevin
- Laboratoire de Physique des Solides, CNRS UMR 8502, Université de Paris Saclay, 91405 Orsay, France
| | - L Liggieri
- CNR - Institute of Condensed Matter Chemistry and Technologies for Energy Unit of Genoa, 16149 Genova, Italy
| | - M Pasquet
- Laboratoire de Physique des Solides, CNRS UMR 8502, Université de Paris Saclay, 91405 Orsay, France
| | - E Rio
- Laboratoire de Physique des Solides, CNRS UMR 8502, Université de Paris Saclay, 91405 Orsay, France
| | - A Salonen
- Laboratoire de Physique des Solides, CNRS UMR 8502, Université de Paris Saclay, 91405 Orsay, France
| | - M Schröter
- Max Planck Institute for Dynamics and Self-Organization, 37077 Göttingen, Germany
| | - M Sperl
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany
| | - R Sütterlin
- Department TESXS Science Systems Engineering, Airbus Defence and Space, Claude Dornier Str., 88090 Immenstaad, Germany
| | - A B Zuccolotto-Bernez
- Condensed Matter Physics Laboratory, Heinrich Heine University, 40225 Düsseldorf, Germany
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5
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Zhang H, Wang X, Yu HB, Douglas JF. Fast dynamics in a model metallic glass-forming material. J Chem Phys 2021; 154:084505. [DOI: 10.1063/5.0039162] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Hao Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Xinyi Wang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Hai-Bin Yu
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Jack F. Douglas
- Material Measurement Laboratory, Material Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
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6
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Rogel Rodriguez D, Alarcon F, Martinez R, Ramírez J, Valeriani C. Phase behaviour and dynamical features of a two-dimensional binary mixture of active/passive spherical particles. SOFT MATTER 2020; 16:1162-1169. [PMID: 31913382 DOI: 10.1039/c9sm01803d] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this work we have characterized the phase behaviour and the dynamics of bidimensional mixtures of active and passive Brownian particles. We have evaluated state diagrams at several concentrations of the passive components finding that, while passive agents tend to hinder phase separation, active agents force crystal-like structures on passive colloids. In order to study how passive particles affect the dynamics of the mixture, we have computed the long-time diffusion coefficient of each species, concluding that active particles induce activity and super-diffusive behaviour on passive ones. Interestingly, at the density at which the system enters a MIPS state the active particles' diffusivity shows an inflection point and the passive particles' one goes through a maximum, due to the change in the dynamics of the active components, as shown in the displacement's probability distribution function.
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Affiliation(s)
- Diego Rogel Rodriguez
- Departamento de Estructura de la Materia, Física Térmica y Electrónica, Universidad Complutense de Madrid, 28040 Madrid, Spain.
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8
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Harrington M, Liu AJ, Durian DJ. Machine learning characterization of structural defects in amorphous packings of dimers and ellipses. Phys Rev E 2019; 99:022903. [PMID: 30934296 DOI: 10.1103/physreve.99.022903] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Indexed: 06/09/2023]
Abstract
Structural defects within amorphous packings of symmetric particles can be characterized using a machine learning approach that incorporates structure functions of radial distances and angular arrangement. This yields a scalar field, softness, that correlates with the probability that a particle is about to be rearranged. However, when particle shapes are elongated, as in the case of dimers and ellipses, we find that the standard structure functions produce imprecise softness measurements. Moreover, ellipses exhibit deformation profiles in stark contrast to circular particles. In order to account for the effects of orientation and alignment, we introduce structure functions to recover the predictive performance of softness, as well as provide physical insight into local and extended dynamics. We study a model disordered solid, a bidisperse two-dimensional granular pillar, driven by uniaxial compression and composed entirely of monomers, dimers, or ellipses. We demonstrate how the computation of softness via a support vector machine extends to dimers and ellipses with the introduction of orientational structure functions. Then we highlight the spatial extent of rearrangements and defects, as well as their cross correlation, for each particle shape. Finally, we demonstrate how an additional machine learning algorithm, recursive feature elimination, provides an avenue to better understand how softness arises from particular structural aspects. We identify the most crucial structure functions in determining softness and discuss their physical implications.
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Affiliation(s)
- Matt Harrington
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Andrea J Liu
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Douglas J Durian
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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9
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Das T, Douglas JF. Quantifying structural dynamic heterogeneity in a dense two-dimensional equilibrium liquid. J Chem Phys 2018; 149:144504. [DOI: 10.1063/1.5037282] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Tamoghna Das
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA and Maryland Nanocenter, University of Maryland, College Park, Maryland 20742, USA
| | - Jack F. Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
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10
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Böbel A, Knapek CA, Räth C. Scale-free crystallization of two-dimensional complex plasmas: Domain analysis using Minkowski tensors. Phys Rev E 2018; 97:053201. [PMID: 29906865 DOI: 10.1103/physreve.97.053201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Indexed: 11/07/2022]
Abstract
Experiments of the recrystallization processes in two-dimensional complex plasmas are analyzed to rigorously test a recently developed scale-free phase transition theory. The "fractal-domain-structure" (FDS) theory is based on the kinetic theory of Frenkel. It assumes the formation of homogeneous domains, separated by defect lines, during crystallization and a fractal relationship between domain area and boundary length. For the defect number fraction and system energy a scale-free power-law relation is predicted. The long-range scaling behavior of the bond-order correlation function shows clearly that the complex plasma phase transitions are not of the Kosterlitz, Thouless, Halperin, Nelson, and Young type. Previous preliminary results obtained by counting the number of dislocations and applying a bond-order metric for structural analysis are reproduced. These findings are supplemented by extending the use of the bond-order metric to measure the defect number fraction and furthermore applying state-of-the-art analysis methods, allowing a systematic testing of the FDS theory with unprecedented scrutiny: A morphological analysis of lattice structure is performed via Minkowski tensor methods. Minkowski tensors form a complete family of additive, motion covariant and continuous morphological measures that are sensitive to nonlinear properties. The FDS theory is rigorously confirmed and predictions of the theory are reproduced extremely well. The predicted scale-free power-law relation between defect fraction number and system energy is verified for one more order of magnitude at high energies compared to the inherently discontinuous bond-order metric. It is found that the fractal relation between crystalline domain area and circumference is independent of the experiment, the particular Minkowski tensor method, and the particular choice of parameters. Thus, the fractal relationship seems to be inherent to two-dimensional phase transitions in complex plasmas. Minkowski tensor analysis turns out to be a powerful tool for investigations of crystallization processes. It is capable of revealing nonlinear local topological properties, however, still provides easily interpretable results founded on a solid mathematical framework.
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Affiliation(s)
- A Böbel
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Münchner Strasse 20, 82234 Weßling
| | - C A Knapek
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Münchner Strasse 20, 82234 Weßling
| | - C Räth
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Münchner Strasse 20, 82234 Weßling
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11
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Salili SM, Harrington M, Durian DJ. Note: Eliminating stripe artifacts in light-sheet fluorescence imaging. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:036107. [PMID: 29604752 DOI: 10.1063/1.5016546] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
We report two techniques to mitigate stripe artifacts in light-sheet fluorescence imaging. The first uses an image processing algorithm called the multidirectional stripe remover method to filter stripes from an existing image. The second uses an elliptical holographic diffuser with strong scattering anisotropy to prevent stripe formation during image acquisition. These techniques facilitate accurate interpretation of image data, especially in denser samples. They are also facile and cost-effective.
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Affiliation(s)
- S M Salili
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - M Harrington
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - D J Durian
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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12
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Rietz F, Radin C, Swinney HL, Schröter M. Nucleation in Sheared Granular Matter. PHYSICAL REVIEW LETTERS 2018; 120:055701. [PMID: 29481202 DOI: 10.1103/physrevlett.120.055701] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 12/11/2017] [Indexed: 06/08/2023]
Abstract
We present an experiment on crystallization of packings of macroscopic granular spheres. This system is often considered to be a model for thermally driven atomic or colloidal systems. Cyclically shearing a packing of frictional spheres, we observe a first order phase transition from a disordered to an ordered state. The ordered state consists of crystallites of mixed fcc and hcp symmetry that coexist with the amorphous bulk. The transition, initiated by homogeneous nucleation, overcomes a barrier at 64.5% volume fraction. Nucleation consists predominantly of the dissolving of small nuclei and the growth of nuclei that have reached a critical size of about ten spheres.
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Affiliation(s)
- Frank Rietz
- Max-Planck-Institute for Dynamics and Self-Organization Göttingen, 37077 Göttingen, Germany
- Institute for Multiscale Simulation, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91052 Erlangen, Germany
- Department of Nonlinear Phenomena, University Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany
- Department of Pattern Formation, University Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany
| | - Charles Radin
- Department of Mathematics, University of Texas at Austin, Austin, Texas 78712, USA
| | - Harry L Swinney
- Center for Nonlinear Dynamics and Department of Physics, University of Texas at Austin, Austin, Texas 78712, USA
| | - Matthias Schröter
- Max-Planck-Institute for Dynamics and Self-Organization Göttingen, 37077 Göttingen, Germany
- Institute for Multiscale Simulation, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91052 Erlangen, Germany
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13
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Zhang G, Stillinger FH, Torquato S. Can exotic disordered "stealthy" particle configurations tolerate arbitrarily large holes? SOFT MATTER 2017; 13:6197-6207. [PMID: 28798966 DOI: 10.1039/c7sm01028a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The probability of finding a spherical cavity or "hole" of arbitrarily large size in typical disordered many-particle systems in the infinite-system-size limit (e.g., equilibrium liquid states) is non-zero. Such "hole" statistics are intimately linked to the thermodynamic and nonequilibrium physical properties of the system. Disordered "stealthy" many-particle configurations in d-dimensional Euclidean space [Doublestruck R]d are exotic amorphous states of matter that lie between a liquid and crystal that prohibit single-scattering events for a range of wave vectors and possess no Bragg peaks [Torquato et al., Phys. Rev. X, 2015, 5, 021020]. In this paper, we provide strong numerical evidence that disordered stealthy configurations across the first three space dimensions cannot tolerate arbitrarily large holes in the infinite-system-size limit, i.e., the hole probability has compact support. This structural "rigidity" property apparently endows disordered stealthy systems with novel thermodynamic and physical properties, including desirable band-gap, optical and transport characteristics. We also determine the maximum hole size that any stealthy system can possess across the first three space dimensions.
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Affiliation(s)
- G Zhang
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA.
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14
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Böbel A, Räth C. Kinetics of fluid demixing in complex plasmas: Domain growth analysis using Minkowski tensors. Phys Rev E 2016; 94:013201. [PMID: 27575224 DOI: 10.1103/physreve.94.013201] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Indexed: 11/07/2022]
Abstract
A molecular dynamics simulation of the demixing process of a binary complex plasma is analyzed and the role of distinct interaction potentials is discussed by using morphological Minkowski tensor analysis of the minority phase domain growth in a demixing simulated binary complex plasma. These Minkowski tensor methods are compared with previous results that utilized a power spectrum method based on the time-dependent average structure factor. It is shown that the Minkowski tensor methods are superior to the previously used power-spectrum method in the sense of higher sensitivity to changes in domain size. By analysis of the slope of the temporal evolution of Minkowski tensor measures, qualitative differences between the case of particle interaction with a single length scale compared to particle interactions with two different length scales (dominating long-range interaction) are revealed. After proper scaling the graphs for the two length scale scenarios coincide, pointing toward universal behavior. The qualitative difference in demixing scenarios is evidenced by distinct demixing behavior: in the long-range dominated cases demixing occurs in two stages. At first, neighboring particles agglomerate, then domains start to merge in cascades. However, in the case of only one interaction length scale only agglomeration but no merging of domains can be observed. Thus, Minkowski tensor analysis is likely to become a useful tool for further investigation of this (and other) demixing processes. It is capable to reveal (nonlinear) local topological properties, probing deeper than (linear) global power-spectrum analysis, however, still providing easily interpretable results founded on a solid mathematical framework.
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Affiliation(s)
- A Böbel
- Forschungsgruppe Komplexe Plasmen, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Argelsrieder Feld 1a, 82234 Wessling, Germany
| | - C Räth
- Forschungsgruppe Komplexe Plasmen, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Argelsrieder Feld 1a, 82234 Wessling, Germany
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15
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Bernini S, Leporini D. Cage effect in supercooled molecular liquids: Local anisotropies and collective solid-like response. J Chem Phys 2016; 144:144505. [DOI: 10.1063/1.4945756] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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16
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Rieser JM, Goodrich CP, Liu AJ, Durian DJ. Divergence of Voronoi Cell Anisotropy Vector: A Threshold-Free Characterization of Local Structure in Amorphous Materials. PHYSICAL REVIEW LETTERS 2016; 116:088001. [PMID: 26967443 DOI: 10.1103/physrevlett.116.088001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Indexed: 06/05/2023]
Abstract
Characterizing structural inhomogeneity is an essential step in understanding the mechanical response of amorphous materials. We introduce a threshold-free measure based on the field of vectors pointing from the center of each particle to the centroid of the Voronoi cell in which the particle resides. These vectors tend to point in toward regions of high free volume and away from regions of low free volume, reminiscent of sinks and sources in a vector field. We compute the local divergence of these vectors, where positive values correspond to overpacked regions and negative values identify underpacked regions within the material. Distributions of this divergence are nearly Gaussian with zero mean, allowing for structural characterization using only the moments of the distribution. We explore how the standard deviation and skewness vary with the packing fraction for simulations of bidisperse systems and find a kink in these moments that coincides with the jamming transition.
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Affiliation(s)
- Jennifer M Rieser
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396, USA
| | - Carl P Goodrich
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396, USA
| | - Andrea J Liu
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396, USA
| | - Douglas J Durian
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396, USA
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17
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Denisov DV, Lörincz KA, Uhl JT, Dahmen KA, Schall P. Universality of slip avalanches in flowing granular matter. Nat Commun 2016; 7:10641. [PMID: 26883071 PMCID: PMC4757786 DOI: 10.1038/ncomms10641] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 01/08/2016] [Indexed: 11/26/2022] Open
Abstract
The search for scale-bridging relations in the deformation of amorphous materials presents a current challenge with tremendous applications in material science, engineering and geology. While generic features in the flow and microscopic dynamics support the idea of a universal scaling theory of deformation, direct microscopic evidence remains poor. Here, we provide the first measurement of internal scaling relations in the deformation of granular matter. By combining macroscopic force fluctuation measurements with internal strain imaging, we demonstrate the existence of robust scaling relations from particle-scale to macroscopic flow. We identify consistent power-law relations truncated by systematic pressure-dependent cutoff, in agreement with recent mean-field theory of slip avalanches in elasto-plastic materials, revealing the existence of a mechanical critical point. These results experimentally establish scale-bridging relations in the flow of matter, paving the way to a new universal theory of deformation. Whether the deformation of amorphous materials is governed by universal scaling, a characteristic feature of the critical phenomena, is currently under debate. Here, Denisov et al. provide experimental evidence by linking the internal strains at microscales to the fluctuations in the applied force.
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Affiliation(s)
- D V Denisov
- Institute of Physics, University of Amsterdam, PO Box 94485, 1090 GL Amsterdam, The Netherlands
| | - K A Lörincz
- Institute of Physics, University of Amsterdam, PO Box 94485, 1090 GL Amsterdam, The Netherlands
| | - J T Uhl
- Department of Physics, University of Illinois at Urbana Champaign, 1110 West Green Street, Urbana, Illinois 61801, USA
| | - K A Dahmen
- Department of Physics, University of Illinois at Urbana Champaign, 1110 West Green Street, Urbana, Illinois 61801, USA
| | - P Schall
- Institute of Physics, University of Amsterdam, PO Box 94485, 1090 GL Amsterdam, The Netherlands
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18
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Morse PK, Corwin EI. Geometric order parameters derived from the Voronoi tessellation show signatures of the jamming transition. SOFT MATTER 2016; 12:1248-1255. [PMID: 26611105 DOI: 10.1039/c5sm02575c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A jammed packing of frictionless spheres at zero temperature is perfectly specified by the network of contact forces from which mechanical properties can be derived. However, we can alternatively consider a packing as a geometric structure, characterized by a Voronoi tessellation which encodes the local environment around each particle. We find that this local environment characterizes systems both above and below jamming and changes markedly at the transition. A variety of order parameters derived from this tessellation carry signatures of the jamming transition, complete with scaling exponents. Furthermore, we define a real space geometric correlation function which also displays a signature of jamming. Taken together, these results demonstrate the validity and usefulness of a purely geometric approach to jamming.
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Affiliation(s)
- Peter K Morse
- Department of Physics and Materials Science Institute, University of Oregon, Eugene, Oregon 97403, USA.
| | - Eric I Corwin
- Department of Physics and Materials Science Institute, University of Oregon, Eugene, Oregon 97403, USA.
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19
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Jakšić ZM, Šćepanović JR, Lončarević I, Budinski-Petković L, Vrhovac SB, Belić A. Structural characterization of submerged granular packings. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 90:062208. [PMID: 25615086 DOI: 10.1103/physreve.90.062208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Indexed: 06/04/2023]
Abstract
We consider the impact of the effective gravitational acceleration on microstructural properties of granular packings through experimental studies of spherical granular materials saturated within fluids of varying density. We characterize the local organization of spheres in terms of contact connectivity, distribution of the Delaunay free volumes, and the shape factor (parameter of nonsphericity) of the Voronoï polygons. The shape factor gives a clear physical picture of the competition between less and more ordered domains of particles in experimentally obtained packings. As the effective gravity increases, the probability distribution of the shape factor becomes narrower and more localized around the lowest values of the shape factor corresponding to regular hexagon. It is found that curves of the pore distributions are asymmetric with a long tail on the right-hand side, which progressively reduces while the effective gravity gets stronger for lower densities of interstitial fluid. We show that the distribution of local areas (Voronoï cells) broadens with decreasing value of the effective gravity due to the formation of lose structures such as large pores and chainlike structures (arches or bridges). Our results should be particularly helpful in testing the newly developed simulation techniques involving liquid-related forces associated with immersed granular particles.
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Affiliation(s)
- Z M Jakšić
- Institute of Physics Belgrade, University of Belgrade, Pregrevica 118, Zemun 11080, Belgrade, Serbia
| | - J R Šćepanović
- Institute of Physics Belgrade, University of Belgrade, Pregrevica 118, Zemun 11080, Belgrade, Serbia
| | - I Lončarević
- Faculty of Engineering, Trg D. Obradovića 6, Novi Sad 21000, Serbia
| | | | - S B Vrhovac
- Institute of Physics Belgrade, University of Belgrade, Pregrevica 118, Zemun 11080, Belgrade, Serbia
| | - A Belić
- Institute of Physics Belgrade, University of Belgrade, Pregrevica 118, Zemun 11080, Belgrade, Serbia
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20
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Williamson JJ, Evans RML. Measuring local volume fraction, long-wavelength correlations, and fractionation in a phase-separating polydisperse fluid. J Chem Phys 2014; 141:164901. [PMID: 25362335 DOI: 10.1063/1.4897560] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Affiliation(s)
- J. J. Williamson
- Department of Physics, Institute for Soft Matter Synthesis and Metrology, Georgetown University, 37th and O Streets, N.W., Washington, D.C. 20057, USA
| | - R. M. L. Evans
- School of Mathematics, University of Leeds, Leeds LS2 9JT, United Kingdom
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21
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Wegner S, Stannarius R, Boese A, Rose G, Szabó B, Somfai E, Börzsönyi T. Effects of grain shape on packing and dilatancy of sheared granular materials. SOFT MATTER 2014; 10:5157-67. [PMID: 24911156 DOI: 10.1039/c4sm00838c] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A granular material exposed to shear shows a variety of unique phenomena: Reynolds dilatancy, positional order and orientational order effects may compete in the shear zone. We study granular packing consisting of macroscopic prolate, oblate and spherical grains and compare their behaviour. X-ray tomography is used to determine the particle positions and orientations in a cylindrical split bottom shear cell. Packing densities and the arrangements of individual particles in the shear zone are evaluated. For anisometric particles, we observe the competition of two opposite effects. On the one hand, the sheared granules are dilated, on the other hand the particles reorient and align with respect to the streamlines. Even though aligned cylinders in principle may achieve higher packing densities, this alignment compensates for the effect of dilatancy only partially. The complex rearrangements lead to a depression of the surface above the well oriented region while neighbouring parts still show the effect of dilation in the form of heaps. For grains with isotropic shapes, the surface remains rather flat. Perfect monodisperse spheres crystallize in the shear zone, whereby positional order partially overcompensates dilatancy effects. However, even slight deviations from the ideal monodisperse sphere shape inhibit crystallization.
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Affiliation(s)
- Sandra Wegner
- Otto-von-Guericke Universität Magdeburg, Institute for Experimental Physics, D-39016 Magdeburg, Germany
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22
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Nordstrom KN, Lim E, Harrington M, Losert W. Granular dynamics during impact. PHYSICAL REVIEW LETTERS 2014; 112:228002. [PMID: 24949789 DOI: 10.1103/physrevlett.112.228002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Indexed: 06/03/2023]
Abstract
We study the impact of a projectile onto a bed of 3 mm grains immersed in an index-matched fluid. We vary the amount of prestrain on the sample, strengthening the force chains within the system. We find this affects only the prefactor of the linear depth-dependent term in the stopping force. We propose a simple model to account for the strain dependence of this term, owing to increased pressure in the pile. Interestingly, we find that the presence of the fluid does not affect the impact dynamics, suggesting that dynamic friction is not a factor. Using a laser sheet scanning technique to visualize internal grain motion, we measure the trajectory of each grain throughout an impact. Microscopically, our results indicate that weaker initial force chains result in more irreversible, plastic rearrangements, suggesting static friction between grains does play a substantial role in the energy dissipation.
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Affiliation(s)
- K N Nordstrom
- Institute for Physical Science and Technology, and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - E Lim
- Department of Physics and Astronomy, Duke University, Durham, North Carolina 27708, USA
| | - M Harrington
- Institute for Physical Science and Technology, and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - W Losert
- Institute for Physical Science and Technology, and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
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23
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Maiti M, Lakshminarayanan A, Sastry S. Characterization of void space in polydisperse sphere packings: Applications to hard-sphere packings and to protein structure analysis. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2013; 36:5. [PMID: 23355091 DOI: 10.1140/epje/i2013-13005-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 10/27/2012] [Accepted: 12/19/2012] [Indexed: 06/01/2023]
Abstract
The implementation of a method for the exact evaluation of the volume and surface area of cavities and free volumes in polydisperse sphere packings is described. The generalization of an algorithm for Voronoi tessellation by Tanemura et al. is presented, employing the radical plane construction, as a part of the method. We employ this method to calculate the equation of state for monodisperse and polydisperse hard-sphere fluids, crystals, and for the metastable amorphous branch up to random close packing or jamming densities. We compute the distribution of free volumes, and compare with previous results employing a heuristic definition of free volume. We show the efficacy of the method for analyzing protein structure, by computing various quantities such as the distribution of sizes of buried cavities and pockets, the scaling of solvent accessible area to the corresponding occupied volume, the composition of residues lining cavities, etc.
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Affiliation(s)
- Moumita Maiti
- Theoretical Sciences Unit, JNCASR, 560065, Jakkur, Banglore, India
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24
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Kurita R, Ruffner DB, Weeks ER. Measuring the size of individual particles from three-dimensional imaging experiments. Nat Commun 2012; 3:1127. [DOI: 10.1038/ncomms2114] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Accepted: 09/04/2012] [Indexed: 12/21/2022] Open
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25
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Ferraro M, Zaninetti L. On the statistics of area size in two-dimensional thick Voronoi diagrams. PHYSICA A: STATISTICAL MECHANICS AND ITS APPLICATIONS 2012; 391:4575-4582. [DOI: 10.1016/j.physa.2012.05.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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26
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Panaitescu A, Reddy KA, Kudrolli A. Nucleation and crystal growth in sheared granular sphere packings. PHYSICAL REVIEW LETTERS 2012; 108:108001. [PMID: 22463455 DOI: 10.1103/physrevlett.108.108001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Indexed: 05/31/2023]
Abstract
We investigate the nucleation of ordered phases, their symmetries, and distributions in dense frictional hard sphere packings as a function of particle volume fraction ϕ, by imposing cyclic shear and constant applied pressure conditions. We show, with internal imaging, that the nucleating crystallites in the bulk consist of 10-60 spheres with hexagonal close packed (hcp) order and nonspherical shape, that are oriented preferentially along the shear axis. Above ϕ=0.62±0.005, crystallites with face centered cubic (fcc) order are observed with increasing probability, and ordered domains grow rapidly. A polycrystalline phase with domains of fcc and hcp order is observed after hundreds of thousands of shear cycles.
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Affiliation(s)
- Andreea Panaitescu
- Department of Physics, Clark University, Worcester, Massachusetts 01610, USA
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27
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Slotterback S, Mailman M, Ronaszegi K, van Hecke M, Girvan M, Losert W. Onset of irreversibility in cyclic shear of granular packings. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 85:021309. [PMID: 22463204 DOI: 10.1103/physreve.85.021309] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Indexed: 05/31/2023]
Abstract
We investigate the onset of irreversibility in a dense granular medium subjected to cyclic shear in a split-bottom geometry. To probe the micro- and mesoscale, we image bead trajectories in three dimensions throughout a series of shear strain oscillations. Although beads lose and regain contact with neighbors during a cycle, the global topology of the contact network exhibits reversible properties for low oscillation amplitudes. With increasing reversal amplitude, a transition to an irreversible diffusive regime occurs.
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Affiliation(s)
- Steven Slotterback
- Department of Physics, and IREAP, University of Maryland, College Park, Maryland 20742, USA.
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28
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Dijksman JA, Rietz F, Lorincz KA, van Hecke M, Losert W. Invited Article: Refractive index matched scanning of dense granular materials. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:011301. [PMID: 22299922 DOI: 10.1063/1.3674173] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We review an experimental method that allows to probe the time-dependent structure of fully three-dimensional densely packed granular materials and suspensions by means of particle recognition. The method relies on submersing a granular medium in a refractive index matched fluid. This makes the resulting suspension transparent. The granular medium is then visualized by exciting, layer by layer, the fluorescent dye in the fluid phase. We collect references and unreported experimental know-how to provide a solid background for future development of the technique, both for new and experienced users.
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Affiliation(s)
- Joshua A Dijksman
- Physics Department, Duke University, Durham, North Carolina 27708-0305, USA
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29
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Mukhopadhyay S, Peixinho J. Packings of deformable spheres. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 84:011302. [PMID: 21867159 DOI: 10.1103/physreve.84.011302] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 06/17/2011] [Indexed: 05/31/2023]
Abstract
We present an experimental study of disordered packings of deformable spheres. Fluorescent hydrogel spheres immersed in water together with a tomography technique enabled the imaging of the three-dimensional arrangement. The mechanical behavior of single spheres subjected to compression is first examined. Then the properties of packings of a randomized collection of deformable spheres in a box with a moving lid are tested. The transition to a state where the packing withstands finite stresses before yielding is observed. Starting from random packed states, the power law dependence of the normal force versus packing fraction or strain at different velocities is quantified. Furthermore, a compression-decompression sequence at low velocities resulted in rearrangements of the spheres. At larger packing fractions, a saturation of the mean coordination number took place, indicating the deformation and faceting of the spheres.
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30
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Herrera M, McCarthy S, Slotterback S, Cephas E, Losert W, Girvan M. Path to fracture in granular flows: dynamics of contact networks. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 83:061303. [PMID: 21797354 DOI: 10.1103/physreve.83.061303] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 05/27/2011] [Indexed: 05/31/2023]
Abstract
Capturing the dynamics of granular flows at intermediate length scales can often be difficult. We propose studying the dynamics of contact networks as a new tool to study fracture at intermediate scales. Using experimental three-dimensional flow fields with particle-scale resolution, we calculate the time evolving broken-links network and find that a giant component of this network is formed as shear is applied to this system. We implement a model of link breakages where the probability of a link breaking is proportional to the average rate of longitudinal strain (elongation) in the direction of the edge and find that the model demonstrates qualitative agreement with the data when studying the onset of the giant component. We note, however, that the broken-links network formed in the model is less clustered than our experimental observations, indicating that the model reflects less localized breakage events and does not fully capture the dynamics of the granular flow.
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Affiliation(s)
- M Herrera
- Department of Physics and IREAP, University of Maryland, College Park, Maryland, USA
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31
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Dijksman JA, Wandersman E, van Hecke M. Follow the bouncing balls! Three-dimensional imaging of flowing granular suspensions. CHAOS (WOODBURY, N.Y.) 2010; 20:041105. [PMID: 21198066 DOI: 10.1063/1.3493418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
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32
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Dijksman JA, Wandersman E, Slotterback S, Berardi CR, Updegraff WD, van Hecke M, Losert W. From frictional to viscous behavior: three-dimensional imaging and rheology of gravitational suspensions. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 82:060301. [PMID: 21230634 DOI: 10.1103/physreve.82.060301] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Revised: 09/23/2010] [Indexed: 05/30/2023]
Abstract
We probe the three-dimensional flow structure and rheology of gravitational (nondensity matched) suspensions for a range of driving rates in a split-bottom geometry. We establish that for sufficiently slow flows, the suspension flows as if it were a dry granular medium, and confirm recent theoretical modeling on the rheology of split-bottom flows. For faster driving, the flow behavior is shown to be consistent with the rheological behavior predicted by the recently developed "inertial number" approaches for suspension flows.
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Affiliation(s)
- Joshua A Dijksman
- Kamerlingh Onnes Lab, Universiteit Leiden, Postbus 9504, 2300 RA Leiden, The Netherlands
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33
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34
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Kurita R, Weeks ER. Experimental study of random-close-packed colloidal particles. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 82:011403. [PMID: 20866616 DOI: 10.1103/physreve.82.011403] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2010] [Indexed: 05/29/2023]
Abstract
A collection of spherical particles can be packed tightly together into an amorphous packing known as "random close packing" (RCP). This structure is of interest as a model for the arrangement of molecules in simple liquids and glasses, as well as the arrangement of particles in sand piles. We use confocal microscopy to study the arrangement of colloidal particles in an experimentally realized RCP state. We image a large volume containing more than 450,000 particles with a resolution of each particle position to better than 0.02 particle diameters. While the arrangement of the particles satisfies multiple criteria for being random, we also observe a small fraction (less than 3%) of tiny crystallites (4 particles or fewer). These regions pack slightly better and are thus associated with locally higher densities. The structure factor of our sample at long length scales is nonzero, S(0)=0.049±0.008, suggesting that there are long wavelength density fluctuations in our sample. These may be due to polydispersity or tiny crystallites. Our results suggest that experimentally realizable RCP systems may be different from simulated RCP systems, in particular, with the presence of these long wavelength density fluctuations.
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Affiliation(s)
- Rei Kurita
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA
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35
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Panaitescu A, Kudrolli A. Spatial distribution functions of random packed granular spheres obtained by direct particle imaging. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 81:060301. [PMID: 20866367 DOI: 10.1103/physreve.81.060301] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2009] [Indexed: 05/29/2023]
Abstract
We measure the two-point density correlations and Voronoi cell distributions of cyclically sheared granular spheres obtained with a fluorescence technique and compare them with random packing of frictionless spheres. We find that the radial distribution function g(r) is captured by the Percus-Yevick equation for initial volume fraction ϕ=0.59. However, small but systematic deviations are observed because of the splitting of the second peak as ϕ is increased toward random close packing. The distribution of the Voronoi free volumes deviates from postulated Γ distributions, and the orientational order metric Q6 shows local order but no long range order. Overall, these measures show significant similarity of random packing of granular and frictionless spheres, but some systematic differences as well.
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Affiliation(s)
- Andreea Panaitescu
- Department of Physics, Clark University, Worcester, Massachusetts 01610, USA
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36
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Karayiannis NC, Foteinopoulou K, Laso M. Contact network in nearly jammed disordered packings of hard-sphere chains. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 80:011307. [PMID: 19658698 DOI: 10.1103/physreve.80.011307] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2009] [Indexed: 05/28/2023]
Abstract
We present salient results of the analysis of the geometrical structure of a large fully equilibrated ensemble of nearly jammed packings of linear freely jointed chains of tangent hard spheres generated via extensive Monte Carlo simulations. In spite the expected differences due to chain connectivity, both the pair-correlation function and the contact network for chain packings are found to strongly resemble those in packings of monomeric hard spheres at the maximally random jammed (MRJ) state. A remarkable finding of the present work is the tendency of chains to form closed loops at the MRJ state as a consequence of chain collapse. Our simulations on disordered nearly jammed chain packings yield an average coordination number of 6, which fulfills the isostaticity condition and is in excellent agreement with the corresponding simulation [A. Donev, S. Torquato, and F. H. Stillinger, Phys. Rev. E 71, 011105 (2005)] and experimental [T. Aste, M. Saadatfar, and T. J. Senden, Phys. Rev. E 71, 061302 (2005)] findings for jammed packings of monatomic hard spheres. An exact correspondence between the statistical-mechanical ensembles of monomeric spheres and of hard-sphere chains offers insights regarding the structure and topology of the contact network of hard-sphere systems at the MRJ state.
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Affiliation(s)
- Nikos Ch Karayiannis
- Institute for Optoelectronics and Microsystems (ISOM) and ETSII, Universidad Politécnica de Madrid (UPM), José Gutiérrez Abascal 2, E-28006 Madrid, Spain
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