COMPACTION OF GRANULAR MATTER: A SHORT REVIEW, AND THE RANDOM TETRIS MODEL

Fractals ◽  
2003 ◽  
Vol 11 (supp01) ◽  
pp. 83-91
Author(s):  
A. BARRAT ◽  
V. LORETO
Keyword(s):  
Granular Matter ◽  
Short Review ◽  
Memory Effects ◽  
Slow Relaxation ◽  
Density Profiles ◽  
Experimental Phenomenology ◽  
Granular Compaction ◽  
Geometrical Constraints

We present a short review of experimental and theoretical aspects of granular compaction, and we discuss in more details the behaviour of the so-called Random Tetris Model, a model of particles diffusing on a lattice, subject to gravity and geometrical constraints. We show how this model reproduces the experimental phenomenology, e.g. slow relaxation, irreversible/reversible cycles, memory effects. The study of the density profiles allows to interpret these results.

scholarly journals SPIN-MODELS OF GRANULAR COMPACTION: FROM ONE-DIMENSIONAL MODELS TO RANDOM GRAPHS

2001 ◽  
Vol 04 (04) ◽  
pp. 309-319 ◽  
Author(s):  
JOHANNES BERG ◽  
ANITA MEHTA
Keyword(s):  
Random Graphs ◽  
Granular Matter ◽  
Spin Hamiltonian ◽  
Spin Models ◽  
One Dimensional ◽  
Granular Assembly ◽  
Geometric Frustration ◽  
Granular Compaction ◽  
Dimensional Models

We discuss two athermal types of dynamics suitable for spin-models designed to model repeated tapping of a granular assembly. These dynamics are applied to a range of models characterized by a 3-spin Hamiltonian aiming to capture the geometric frustration in packings of granular matter.

scholarly journals Slow relaxation in granular compaction

1998 ◽  
Vol 123 (1-4) ◽  
pp. 380-385 ◽  
Author(s):  
E. Ben-Naim ◽  
J.B. Knight ◽  
E.R. Nowak ◽  
H.M. Jaeger ◽  
S.R. Nagel
Keyword(s):  
Slow Relaxation ◽  
Granular Compaction

scholarly journals Mitigating memory effects during undulatory locomotion on hysteretic materials

2019 ◽  
Author(s):  
Perrin E. Schiebel ◽  
Henry C. Astley ◽  
Jennifer M. Rieser ◽  
Shashank Agarwal ◽  
Christian Hubicki ◽  
...  
Keyword(s):  
Granular Matter ◽  
Memory Effects ◽  
Escape Performance ◽  
Wave Shape ◽  
Reaction Forces ◽  
Granular Physics ◽  
Undulatory Locomotion ◽  
Resistive Force Theory ◽  
Undulatory Swimming ◽  
Body Inertia

Undulatory swimming in flowing media like water is well-studied, but little is known about loco-motion in environments that are permanently deformed by body–substrate interactions like snakes in sand, eels in mud, and nematode worms in rotting fruit. We study the desert-specialist snake Chion-actis occipitalis traversing granular matter and find body inertia is negligible despite rapid transit and speed dependent granular reaction forces. New surface resistive force theory (RFT) calculation reveals how this snakes wave shape minimizes memory effects and optimizes escape performance given physiological limitations (power). RFT explains the morphology and waveform dependent performance of a diversity of non-sand-specialist, but overpredicts the capability of snakes with high slip. Robophysical experiments recapitulate aspects of these failure-prone snakes and elucidate how reencountering previously remodeled material hinders performance. This study reveals how memory effects stymied the locomotion of a diversity of snakes in our previous studies [Marvi et al, Science, 2014] and suggests the existence of a predictive model for history-dependent granular physics.

Pollutant Identification by Selected Area Electron Diffraction

1974 ◽  
Vol 32 ◽  
pp. 532-533
Author(s):  
R. E. Ferrell ◽  
G. G. Paulson ◽  
C. W. Walker
Keyword(s):  
Thermal Treatment ◽  
Electron Diffraction ◽  
Sample Preparation ◽  
Crystal Structures ◽  
Water Samples ◽  
Environmental Samples ◽  
Short Review ◽  
Selected Area Electron Diffraction ◽  
Multiple Component

Selected area electron diffraction (SAD) has been used successfully to determine crystal structures, identify traces of minerals in rocks, and characterize the phases formed during thermal treatment of micron-sized particles. There is an increased interest in the method because it has the potential capability of identifying micron-sized pollutants in air and water samples. This paper is a short review of the theory behind SAD and a discussion of the sample preparation employed for the analysis of multiple component environmental samples.

Plastic Deformation in Microtomed Sections

1971 ◽  
Vol 29 ◽  
pp. 458-459
Author(s):  
J. Temple Black
Keyword(s):  
Plastic Deformation ◽  
Plastic Strain ◽  
Applied Stress ◽  
Elastic Strain ◽  
High Strain ◽  
Tool Material ◽  
Cutting Edge ◽  
Material Structure ◽  
Geometrical Constraints

The output of the ultramicrotomy process with its high strain levels is dependent upon the input, ie., the nature of the material being machined. Apart from the geometrical constraints offered by the rake and clearance faces of the tool, each material is free to deform in whatever manner necessary to satisfy its material structure and interatomic constraints. Noncrystalline materials appear to survive the process undamaged when observed in the TEM. As has been demonstrated however microtomed plastics do in fact suffer damage to the top and bottom surfaces of the section regardless of the sharpness of the cutting edge or the tool material. The energy required to seperate the section from the block is not easily propogated through the section because the material is amorphous in nature and has no preferred crystalline planes upon which defects can move large distances to relieve the applied stress. Thus, the cutting stresses are supported elastically in the internal or bulk and plastically in the surfaces. The elastic strain can be recovered while the plastic strain is not reversible and will remain in the section after cutting is complete.

POPDC proteins and cardiac function

2019 ◽  
Vol 47 (5) ◽  
pp. 1393-1404 ◽  
Author(s):  
Thomas Brand
Keyword(s):  
Potential Role ◽  
Striated Muscle ◽  
Short Review ◽  
Effector Proteins ◽  
Muscle Disease ◽  
Disease Genes ◽  
Protein Protein Interaction ◽  
Interaction Partners ◽  
And Function

Abstract The Popeye domain-containing gene family encodes a novel class of cAMP effector proteins in striated muscle tissue. In this short review, we first introduce the protein family and discuss their structure and function with an emphasis on their role in cyclic AMP signalling. Another focus of this review is the recently discovered role of POPDC genes as striated muscle disease genes, which have been associated with cardiac arrhythmia and muscular dystrophy. The pathological phenotypes observed in patients will be compared with phenotypes present in null and knockin mutations in zebrafish and mouse. A number of protein–protein interaction partners have been discovered and the potential role of POPDC proteins to control the subcellular localization and function of these interacting proteins will be discussed. Finally, we outline several areas, where research is urgently needed.

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