Publications
138 results found
Wang X, Blumenfeld R, Feng X-Q, et al., 2022, ?Phase transitions? in bacteria-From structural transitions in free living bacteria to phenotypic transitions in bacteria within biofilms, PHYSICS OF LIFE REVIEWS, Vol: 43, Pages: 98-138, ISSN: 1571-0645
Yanagida A, Corujo-Simon E, Revell CK, et al., 2022, Cell surface fluctuations regulate early embryonic lineage sorting., Cell, Vol: 185
Yanagida A, Corujo-Simon E, Revell CK, et al., 2022, Cell surface fluctuations regulate early embryonic lineage sorting, CELL, Vol: 185, Pages: 777-+, ISSN: 0092-8674
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- Citations: 7
Blumenfeld R, 2021, Erratum: Disorder Criterion and Explicit Solution for the Disc Random Packing Problem [Phys. Rev. Lett. 127, 118002 (2021)]., Phys Rev Lett, Vol: 127
This corrects the article DOI: 10.1103/PhysRevLett.127.118002.
Blumenfeld R, 2021, Disorder Criterion and Explicit Solution for the Disc Random Packing Problem, PHYSICAL REVIEW LETTERS, Vol: 127, ISSN: 0031-9007
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- Citations: 4
He J, Blumenfeld R, Zhu H, 2021, Mechanical Behaviors of Sandy Sediments Bearing Pore-Filling Methane Hydrate under Different Intermediate Principal Stress, INTERNATIONAL JOURNAL OF GEOMECHANICS, Vol: 21, ISSN: 1532-3641
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- Citations: 6
Liu P, Ran X, Cheng Q, et al., 2021, Locomotion of Self-Excited Vibrating and Rotating Objects in Granular Environments, APPLIED SCIENCES-BASEL, Vol: 11
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- Citations: 1
Sun X, Kob W, Blumenfeld R, et al., 2020, Friction-Controlled Entropy-Stability Competition in Granular Systems, PHYSICAL REVIEW LETTERS, Vol: 125, ISSN: 0031-9007
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- Citations: 10
Wanjura C, Gago P, Matsushima T, et al., 2020, Structural evolution of granular systems: theory, Granular Matter, Vol: 22, ISSN: 1434-5021
A general theory is developed for the evolution of the cell order (CO) distribution in planar granular systems. Dynamic equations are constructed and solved in closed form for several examples: systems under compression; dilation of very dense systems; and the general approach to steady state. We find that all the steady states are stable and that they satisfy a detailed balance-like condition when the CO≤6. Illustrative numerical solutions of the evolution are shown. Our theoretical results are validated against an extensive simulation of a sheared system. The formalism can be readily extended to other structural characteristics, paving the way to a general theory of structural organisation of granular systems.
Ouyang H, Xiao Y, Hu S, et al., 2020, Establishment and application of comprehensive evaluation method for automobile technical performance, Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology), Vol: 51, Pages: 650-660, ISSN: 1672-7207
A multidimensional evaluation scheme was constructed consisting of a technical performance indicator H, a mass-weighted measure of the effect of the technical parameters W and a measure of the price efficiency N.These indexes were functions of primary performance indicators,which included constant speed fuel consumption,braking distance in the maximum speed 0-100 km/h, engine volume, mass and price.Vehicle indetified method was proposed taking W as the most useful indicator for comparing different vehicles and models. The correlations between the technical performance, price and sales of several major car models in Chinese market were studied.The results show that different car models have significantly different performance indices with joint-venture generally outperforming domestic ones on technical performance, but underperforming on price. There are distinct differences in consumers' selection criteria for cars, SUVs and MPVs. Consumers care more about the technical performance and brand of products for cars,while they care more about the comprehensive ability for SUVs, practicality and cost-effectiveness for MPVs. Breakthrough in high performance and small engines, high capacity battery and motor system, light weight and intelligent vehicles and driving technology (oil-electric vehicles, extended-range vehicles, especially all-wheel drive and integration of driving and braking system) can boost the Chinese vehicle industry development.
Blumenfeld R, 2020, The unusual problem of upscaling isostaticity theory for granular matter, GRANULAR MATTER, Vol: 22, ISSN: 1434-5021
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- Citations: 1
Feng Y, Blumenfeld R, Liu C, 2019, Support of modified Archimedes' law theory in granular media, SOFT MATTER, Vol: 15, Pages: 3008-3017, ISSN: 1744-683X
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- Citations: 15
Revell C, Blumenfeld R, Chalut KJ, 2019, Force-based three-dimensional model predicts mechanical drivers of cell sorting, Proceedings of the Royal Society B: Biological Sciences, Vol: 286, ISSN: 0962-8452
© 2019 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited. Many biological processes, including tissue morphogenesis, are driven by cell sorting. However, the primary mechanical drivers of sorting in multicellular aggregates (MCAs) remain controversial, in part because there is no appropriate computational model to probe mechanical interactions between cells. To address this important issue, we developed a three-dimensional, local force-based simulation based on the subcellular element method. In our method, cells are modelled as collections of locally interacting force-bearing elements. We use the method to investigate the effects of tension and cell - cell adhesion on MCA sorting. We predict a minimum level of adhesion to produce inside-out sorting of two cell types, which is in excellent agreement with observations in several developmental systems. We also predict the level of tension asymmetry needed for robust sorting. The generality and flexibility of the method make it applicable to tissue self-organization in a myriad of other biological processes, such as tumorigenesis and embryogenesis.
Schwartz M, Blumenfeld R, 2018, Stress-strain rate relation in plug-free flow of dense granular fluids: A first-principles derivation, PHYSICAL REVIEW E, Vol: 98, ISSN: 2470-0045
Verstreken CM, Chalut KJ, Blumenfeld R, 2018, Equally probable positive and negative Poisson's ratios in disordered planar systems, SOFT MATTER, Vol: 14, Pages: 6554-6560, ISSN: 1744-683X
Kang W, Feng Y, Liu C, et al., 2018, Archimedes' law explains penetration of solids into granular media, NATURE COMMUNICATIONS, Vol: 9, ISSN: 2041-1723
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- Citations: 49
Cheng Q, Ran X-W, Liu P, et al., 2018, Numerical simulation of a spinning sphere moving in granular matter, ACTA PHYSICA SINICA, Vol: 67, ISSN: 1000-3290
Amitai S, Bertei A, Blumenfeld R, 2017, Theory-based design of sintered granular composites triples three-phase boundary in fuel cells, PHYSICAL REVIEW E, Vol: 96, ISSN: 2470-0045
Blumenfeld R, Amitai S, Jordan JF, et al., 2017, Comment on "Failure of the Volume Function in Granular Statistical Mechanics and an Alternative Formulation" Reply, PHYSICAL REVIEW LETTERS, Vol: 119, ISSN: 0031-9007
Amitai S, Blumenfeld R, 2017, Affine and topogical structural entropies in granular statistical mechanics: Explicit calculations and equation of state, Physical Review E, Vol: 95, ISSN: 1539-3755
We identify two orthogonal sources of structural entropy in rattler-free granular systems: affine, involving structural changes that only deform the contact network, and topological, corresponding to different topologies of the contact network. We show that a recently developed connectivity-based granular statistical mechanics separates the two naturally by identifying the structural degrees of freedom with spanning trees on the graph of the contact network. We extend the connectivity-based formalism to include constraints on, and correlations between, degrees of freedom as interactions between branches of the spanning tree. We then use the statistical mechanics formalism to calculate the partition function generally and the different entropies in the high-angoricity limit. We also calculate the degeneracy of the affine entropy and a number of expectation values. From the latter, we derive an equipartition principle and an equation of state relating the macroscopic volume and boundary stress to the analog of the temperature, the contactivity.
Blumenfeld R, Ma J, 2017, Bending back stress chains and unique behaviour of granular matter in cylindrical geometries, GRANULAR MATTER, Vol: 19, ISSN: 1434-5021
We analyse the general solutions for the stress field in planar annuli of isostatic media, a model often used for marginally rigid granular materials in Couette cells. We demonstrate that these solutions are much richer than in rectangular symmetries. Even for uniform media, stress chains are found to curve, broaden away from the stress source, attenuate and leak stress into a cone of influence. Most spectacularly, stress chains may bend back and transmit forces oppositely to the original direction. None of these phenomena arises in solutions for uniform media in Cartesian coordinates. We further analyse non-uniform media, which exhibit chain branching and stress leakage from the chains. These results are directly relevant to the many experiments on granular materials, carried out in Couette cells. They also shed light on, and are supported by, hitherto unexplained experimental observations of curved and back-bending chains, which we point out. In particular, we use our results to provide a new interpretation for the pattern of slip lines observed experimentally.
Matsushima T, Blumenfeld R, 2017, Fundamental structural characteristics of planar granular assemblies: Self-organization and scaling away friction and initial state, PHYSICAL REVIEW E, Vol: 95, ISSN: 2470-0045
Amitai S, Blumenfeld R, 2017, Modifying continuous-time random walks to model finite-size particle diffusion in granular porous media, Granular Matter, Vol: 19, ISSN: 1434-5021
The continuous-time random walk (CTRW) model is useful for alleviating the computational burden of simulating diffusion in actual media. In principle, isotropic CTRW only requires knowledge of the step-size, PlPl , and waiting-time, PtPt , distributions of the random walk in the medium and it then generates presumably equivalent walks in free space, which are much faster. Here we test the usefulness of CTRW to modelling diffusion of finite-size particles in porous medium generated by loose granular packs. This is done by first simulating the diffusion process in a model porous medium of mean coordination number, which corresponds to marginal rigidity (the loosest possible structure), computing the resulting distributions PlPl and PtPt as functions of the particle size, and then using these as input for a free space CTRW. The CTRW walks are then compared to the ones simulated in the actual media. In particular, we study the normal-to-anomalous transition of the diffusion as a function of increasing particle size. We find that, given the same PlPl and PtPt for the simulation and the CTRW, the latter predicts incorrectly the size at which the transition occurs. We show that the discrepancy is related to the dependence of the effective connectivity of the porous media on the diffusing particle size, which is not captured simply by these distributions. We propose a correcting modification to the CTRW model—adding anisotropy—and show that it yields good agreement with the simulated diffusion process. We also present a method to obtain PlPl and PtPt directly from the porous sample, without having to simulate an actual diffusion process. This extends the use of CTRW, with all its advantages, to modelling diffusion processes of finite-size particles in such confined geometries.
Blumenfeld R, Edwards SF, Walley SM, 2017, Physics of granular systems, The Oxford Handbook of Soft Condensed Matter, Pages: 167-232, ISBN: 9780199667925
This article discusses the fundamental physics of granular systems. It begins with an overview of the science of granular matter, followed by a description of the ‘micro’-structure on the granular level. It then considers stress transmission in mechanically equilibrated granular assemblies, focusing on conditions for marginal rigidity, isostaticity theory, and limitations of linear stress theories. It also examines the use of statistical mechanics to analyse and classify granular materials, taking into account the micro-canonical volume ensemble, structural degrees of freedom, the canonical volume ensemble and the quasi-particles of the volume ensemble, the stress ensemble, and the relationship between the volume and stress ensembles. The article concludes with an assessment of recent advances in the ongoing attempt to construct a statistical mechanical theory of granular systems.
Huang L, Ran X, Blumenfeld R, 2016, Vertical dynamics of a horizontally oscillating active object in a two-dimensional granular medium., Physical Review E, Vol: 94, ISSN: 1539-3755
We use a discrete-element method simulation and analytical considerations to study the dynamics of a self-energized object, modeled as a disk, oscillating horizontally within a two-dimensional bed of denser and smaller particles. We find that, for given material parameters, the immersed object (IO) may rise, sink, or not change depth, depending on the oscillation amplitude and frequency, as well as on the initial depth. With time, the IO settles at a specific depth that depends on the oscillation parameters. We construct a phase diagram of this behavior in the oscillation frequency and velocity amplitude variable space. We explain the observed rich behavior by two competing effects: climbing on particles, which fill voids opening under the disk, and sinking due to bed fluidization. We present a cavity model that allows us to derive analytically general results, which agree very well with the observations and explain quantitatively the phase diagram. Our specific analytical results are the following. (i) Derivation of a critical frequency, f_{c}, above which the IO cannot float up against gravity. We show that this frequency depends only on the gravitational acceleration and the IO size. (ii) Derivation of a minimal amplitude, A_{min}, below which the IO cannot rise even if the frequency is below f_{c}. We show that this amplitude also depends only on the gravitational acceleration and the IO size. (iii) Derivation of a critical value, g_{c}, of the IO's acceleration amplitude, below which the IO cannot sink. We show that the value of g_{c} depends on the characteristics of both the IO and the granular bed, as well as on the initial IO's depth.
Blumenfeld R, Amitai S, Jordan JF, et al., 2016, Failure of the Volume Function in Granular Statistical Mechanics and an Alternative Formulation, Physical Review Letters, Vol: 116, ISSN: 0031-9007
We first show that the currently accepted statistical mechanics for granular matter is flawed. The reason is that it is based on the volume function, which depends only on a minute fraction of all the structural degrees of freedom and is unaffected by most of the configurational microstates. Consequently, the commonly used partition function underestimates the entropy severely. We then propose a new formulation, replacing the volume function with a connectivity function that depends on all the structural degrees of freedom and accounts correctly for the entire entropy. We discuss the advantages of the new formalism and derive explicit results for two- and three-dimensional systems. We test the formalism by calculating the entropy of an experimental two-dimensional system, as a function of system size, and showing that it is an extensive variable.
Blumenfeld R, Edwards SF, 2014, Granular statistical mechanics - a personal perspective, EUROPEAN PHYSICAL JOURNAL-SPECIAL TOPICS, Vol: 223, Pages: 2189-2204, ISSN: 1951-6355
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- Citations: 4
Matsushima T, Blumenfeld R, 2014, Universal Structural Characteristics of Planar Granular Packs, PHYSICAL REVIEW LETTERS, Vol: 112, ISSN: 0031-9007
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- Citations: 16
Matsushima T, Blumenfeld R, 2013, Microstructural characteristics of planar granular solids, POWDERS AND GRAINS 2013, Vol: 1542, Pages: 325-328, ISSN: 0094-243X
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- Citations: 2
Blumenfeld R, Jordan JF, Edwards SF, 2013, Granular Statistical Mechanics: Volume-Stress Phase Space, Equipartition and Equations of State, 7th International Conference on Micromechanics of Granular Media (Powders and Grains), Publisher: AMER INST PHYSICS, Pages: 1186-1189, ISSN: 0094-243X
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- Citations: 1
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