Increase in chaotic motions of atoms in a large-scale self-organized motion

1996 ◽  
Vol 54 (2) ◽  
pp. 1504-1509 ◽  
Author(s):  
Tadashi Watanabe ◽  
Hideo Kaburaki
Keyword(s):  
Large Scale ◽  
Chaotic Motions ◽  
Self Organized

scholarly journals Order out of chaos: Shifting paradigm of convective turbulence

2021 ◽  
Author(s):  
Sergej Zilitinkevich ◽  
Evgeny Kadantsev ◽  
Irina Repina ◽  
Evgeny Mortikov ◽  
Andrey Glazunov
Keyword(s):  
Large Scale ◽  
Vertical Mixing ◽  
Fluid Flows ◽  
Stratified Turbulence ◽  
Conventional Theory ◽  
New Paradigm ◽  
Chaotic Motions ◽  
Low Viscosity ◽  
Self Organized ◽  
Almost All

AbstractTurbulence is ever produced in the low-viscosity/large-scale fluid flows by the velocity shears and, in unstable stratification, by buoyancy forces. It is commonly believed that both mechanisms produce the same type of chaotic motions, namely, the eddies breaking down into smaller ones and producing direct cascade of turbulent kinetic energy and other properties from large to small scales towards viscous dissipation. The conventional theory based on this vision yields a plausible picture of vertical mixing and remains in use since the middle of the 20th century in spite of increasing evidence of the fallacy of almost all other predictions. This paper reveals that in fact buoyancy produces chaotic vertical plumes, merging into larger ones and producing an inverse cascade towards their conversion into the self-organized regular motions. Herein, the velocity shears produce usual eddies spreading in all directions and making the direct cascade. This new paradigm is demonstrated and proved empirically; so, the paper launches a comprehensive revision of the theory of unstably stratified turbulence and its numerous geophysical or astrophysical applications.

Modeling Extinction

2003 ◽  
Author(s):  
M. E. J. Newman ◽  
R. G. Palmer
Keyword(s):  
Evolutionary Biology ◽  
Large Scale ◽  
Competitive Exclusion ◽  
Applied Mathematics ◽  
Santa Fe ◽  
New Approach ◽  
Self Organized ◽  
Self Organized Criticality ◽  
Extinction Events ◽  
Mass Extinction Events

Developed after a meeting at the Santa Fe Institute on extinction modeling, this book comments critically on the various modeling approaches. In the last decade or so, scientists have started to examine a new approach to the patterns of evolution and extinction in the fossil record. This approach may be called "statistical paleontology," since it looks at large-scale patterns in the record and attempts to understand and model their average statistical features, rather than their detailed structure. Examples of the patterns these studies examine are the distribution of the sizes of mass extinction events over time, the distribution of species lifetimes, or the apparent increase in the number of species alive over the last half a billion years. In attempting to model these patterns, researchers have drawn on ideas not only from paleontology, but from evolutionary biology, ecology, physics, and applied mathematics, including fitness landscapes, competitive exclusion, interaction matrices, and self-organized criticality. A self-contained review of work in this field.

scholarly journals Topology assisted self-organization of colloidal nanoparticles: application to 2D large-scale nanomastering

2014 ◽  
Vol 5 ◽  
pp. 1203-1209 ◽  
Author(s):  
Hind Kadiri ◽  
Serguei Kostcheev ◽  
Daniel Turover ◽  
Rafael Salas-Montiel ◽  
Komla Nomenyo ◽  
...  
Keyword(s):  
Large Scale ◽  
The Self ◽  
Surface Topology ◽  
Self Organization ◽  
Hydrogen Silsesquioxane ◽  
Polystyrene Beads ◽  
Structure Topology ◽  
Self Organized ◽  
Novel Method ◽  
Long Range Ordering

Our aim was to elaborate a novel method for fully controllable large-scale nanopatterning. We investigated the influence of the surface topology, i.e., a pre-pattern of hydrogen silsesquioxane (HSQ) posts, on the self-organization of polystyrene beads (PS) dispersed over a large surface. Depending on the post size and spacing, long-range ordering of self-organized polystyrene beads is observed wherein guide posts were used leading to single crystal structure. Topology assisted self-organization has proved to be one of the solutions to obtain large-scale ordering. Besides post size and spacing, the colloidal concentration and the nature of solvent were found to have a significant effect on the self-organization of the PS beads. Scanning electron microscope and associated Fourier transform analysis were used to characterize the morphology of the ordered surfaces. Finally, the production of silicon molds is demonstrated by using the beads as a template for dry etching.

Self Organized Structure of Microbubble Plume in a Thin Fluid Layer

2011 ◽  
Author(s):  
Yoshihito Miyagishima ◽  
Tomoaki Watamura ◽  
Yuji Tasaka ◽  
Yuichi Murai
Keyword(s):  
Liquid Phase ◽  
Large Scale ◽  
Fluid Layer ◽  
Bubbly Flow ◽  
The Self ◽  
Bubbly Flows ◽  
Bubble Plume ◽  
Accumulation Pattern ◽  
Thin Fluid ◽  
Self Organized

This study aims to clarify the self-organized structure of microbubble plume as a result of two-way interaction between microbubbles and a flow of the surrounding liquid medium. We observed a sequence on a development of microbubble plumes in a thin fluid layer. Here the microbubbles show accumulation pattern with a different wavenumber depending on the height in the vessel. Variation of spatial wavenumber in the developing process was determined from visualization images, and three areas were distinguished in this process; (1) the area of rising microbubbles with a large wavenumber in a horizontal direction without time dependence; (2) the area of forming a large-scale flow structure, called ‘microbubble plume’ here, which keeps the primary information, horizontal wavenumber of the bubble accumulation with a large wavenumber; (3) the area where the microbubble distribution takes a smaller wavenumber and makes vertical accumulation pattern inside the bubbly flow that is due to the mutual interaction between rising microbubbles and a flow induced by bubbles. To clarify these mutual interactions between liquid and gas phases, we visualized fluid motion of the liquid phase around the microbubble plumes by laser induced fluorescence, LIF. In this way, swaying motions on the tip of rising up bubble plume and liquid phase entrainment into the bubble plumes were visualized. We found the mechanisms for the creation of the self-organized distribution of microbubbles in bubbly flows and its temporal change as the result of the interaction between gas and liquid phase motions in bubbly flows.

scholarly journals Biogenic gradients in algal density affect the emergent properties of spatially self-organized mussel beds

2014 ◽  
Vol 11 (96) ◽  
pp. 20140089 ◽  
Author(s):  
Quan-Xing Liu ◽  
Ellen J. Weerman ◽  
Rohit Gupta ◽  
Peter M. J. Herman ◽  
Han Olff ◽  
...  
Keyword(s):  
Large Scale ◽  
Scale Effects ◽  
Water Layer ◽  
Theoretical Models ◽  
Emergent Properties ◽  
Stable States ◽  
Mussel Beds ◽  
Self Organized ◽  
Proposed Model ◽  
Secondary Productivity

Theoretical models highlight that spatially self-organized patterns can have important emergent effects on the functioning of ecosystems, for instance by increasing productivity and affecting the vulnerability to catastrophic shifts. However, most theoretical studies presume idealized homogeneous conditions, which are rarely met in real ecosystems. Using self-organized mussel beds as a case study, we reveal that spatial heterogeneity, resulting from the large-scale effects of mussel beds on their environment, significantly alters the emergent properties predicted by idealized self-organization models that assume homogeneous conditions. The proposed model explicitly considers that the suspended algae, the prime food for the mussels, are supplied by water flow from the seaward boundary of the bed, which causes in combination with consumption a gradual depletion of algae over the simulated domain. Predictions of the model are consistent with properties of natural mussel patterns observed in the field, featuring a decline in mussel biomass and a change in patterning. Model analyses reveal a fundamental change in ecosystem functioning when this self-induced algal depletion gradient is included in the model. First, no enhancement of secondary productivity of the mussels comparing with non-patterns states is predicted, irrespective of parameter setting; the equilibrium amount of mussels is entirely set by the input of algae. Second, alternate stable states, potentially present in the original (no algal gradient) model, are absent when gradual depletion of algae in the overflowing water layer is allowed. Our findings stress the importance of including sufficiently realistic environmental conditions when assessing the emergent properties of self-organized ecosystems.

scholarly journals Deep rotating convection generates the polar hexagon on Saturn

2020 ◽  
Vol 117 (25) ◽  
pp. 13991-13996 ◽  
Author(s):  
Rakesh K. Yadav ◽  
Jeremy Bloxham
Keyword(s):  
Flow Pattern ◽  
High Latitude ◽  
Large Scale ◽  
Three Dimensional ◽  
Giant Planets ◽  
Zonal Flows ◽  
Self Organized ◽  
Consistent Model ◽  
Self Consistent ◽  
Polygonal Pattern

Numerous land- and space-based observations have established that Saturn has a persistent hexagonal flow pattern near its north pole. While observations abound, the physics behind its formation is still uncertain. Although several phenomenological models have been able to reproduce this feature, a self-consistent model for how such a large-scale polygonal jet forms in the highly turbulent atmosphere of Saturn is lacking. Here, we present a three-dimensional (3D) fully nonlinear anelastic simulation of deep thermal convection in the outer layers of gas giant planets that spontaneously generates giant polar cyclones, fierce alternating zonal flows, and a high-latitude eastward jet with a polygonal pattern. The analysis of the simulation suggests that self-organized turbulence in the form of giant vortices pinches the eastward jet, forming polygonal shapes. We argue that a similar mechanism is responsible for exciting Saturn’s hexagonal flow pattern.

scholarly journals Self-organized criticality and the fractal scaling of a predator-prey interaction

1992 ◽  
Vol 6 ◽  
pp. 11-11
Author(s):  
Richard B. Aronson
Keyword(s):  
Large Scale ◽  
Interactive Systems ◽  
Small Scale ◽  
Biological Interactions ◽  
Ecological Processes ◽  
The Bahamas ◽  
Fractal Scaling ◽  
Self Organized ◽  
Predation Effects ◽  
Self Organized Criticality

In many cases, it is not possible to explain evolutionary-scale patterns by analogy to ecological processes. However, in at least some cases, biological interactions appear amenable to such extrapolation. The paleobiological literature contains examples of predation, competition, and herbivory in which the dynamics are similar on multiple spatiotemporal scales.Dense populations of epifaunal, suspension-feeding ophiuroids, or brittlestar beds, are widely distributed, but they are rare and are restricted in their habitat distribution. On a small scale (meters to kilometers, hours to days), brittlestar bed distribution in the British Isles and the Bahamas is limited by predatory fishes and crabs. On an intermediate scale (tens to hundreds of kilometers, decades to centuries), predation by seastars may cause cycles of ophiuroid abundance in the western English Channel, beyond the stringent restrictions imposed by fish and crab predators. On a large scale (globally, millions to tens of millions of years), the Jurassic decline of brittlestar beds is associated with the diversification of predatory teleosts, neoselachian sharks, and decapod crustaceans.Small-scale predator-ophiuroid interactions sum to produce analogous intermediate- and large-scale interactions. Predation effects on brittlestar beds appear to be scale-independent, or fractal. Fractal scaling may be a consequence of self-organized criticality, an inherent property of large, interactive systems.

scholarly journals World’s largest dam removal reverses coastal erosion

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jonathan A. Warrick ◽  
Andrew W. Stevens ◽  
Ian M. Miller ◽  
Shawn R. Harrison ◽  
Andrew C. Ritchie ◽  
...  
Keyword(s):  
Coastal Erosion ◽  
Large Scale ◽  
River Mouth ◽  
Dam Removal ◽  
Ocean Waves ◽  
Sediment Supply ◽  
Sediment Budgets ◽  
Self Organized ◽  
Wave Angle ◽  
Mouth Bars

Abstract Coastal erosion outpaces land generation along many of the world’s deltas and a significant percentage of shorelines, and human-caused alterations to coastal sediment budgets can be important drivers of this erosion. For sediment-starved and erosion-prone coasts, large-scale enhancement of sediment supply may be an important, but poorly understood, management option. Here we provide new topographic measurements that show patterns and trends of beach accretion following the restoration of sediment supply from a massive dam removal project. River sediment was initially deposited in intertidal-to-subtidal deltaic lobes, and this sediment was reworked by ocean waves into subaerial river mouth bars over time scales of several months. These river mouth bars welded to the shoreline and then initiated waves of sediment accretion along adjacent upcoast and downcoast beaches. Although the downcoast shoreline has a high wave-angle setting, the sedimentation waves straightened the downcoast shoreline rather than forming self-organized quasi-periodic instabilities, which suggests that simple coastal evolution theory did not hold under these conditions. Combined with other mega-nourishment projects, these findings provide new understanding of littoral responses to the restoration of sediment supplies.

Adaptive Self-Organization in Distributed Tree Topologies

2014 ◽  
Vol 5 (3) ◽  
pp. 24-57 ◽  
Author(s):  
Evangelos Pournaras ◽  
Martijn Warnier ◽  
Frances M.T. Brazier
Keyword(s):  
Large Scale ◽  
Overlay Networks ◽  
Adaptation Strategies ◽  
Self Organization ◽  
Self Organized ◽  
Trade Offs ◽  
Organization Process ◽  
Tree Topologies ◽  
Hierarchical Communication ◽  
Message Overhead

Tree topologies are often deployed in large-scale distributed systems to structure a hierarchical communication. Building and maintaining overlay networks self-organized in tree topologies is challenging to achieve in dynamic environments. Performance trade-offs between resilience to failures and message overhead need to be considered. This paper introduces eight adaptation strategies that provide a higher abstraction, modularity and reconfigurability in the tree self-organization process. Performance can be further enhanced by dynamically changing strategies during system runtime. Experimental evaluation illustrates the performance trade-offs and properties of adaptation strategies.

Beernet

2012 ◽  
pp. 282-304
Author(s):  
B. Mejías ◽  
P. Van Roy
Keyword(s):  
Distributed Systems ◽  
Large Scale ◽  
Single Point ◽  
Peer To Peer ◽  
Self Healing ◽  
Decentralized System ◽  
Large Scale Systems ◽  
Self Organized ◽  
Peer To Peer Networks ◽  
Control And Synchronization

Distributed systems with a centralized architecture present the well known problems of single point of failure and single point of congestion; therefore, they do not scale. Decentralized systems, especially as peer-to-peer networks, are gaining popularity because they scale well, and do not need a server to work. However, their complexity is higher due to the lack of a single point of control and synchronization, and because consistent decentralized storage is difficult to maintain when data constantly evolves. Self-management is a way of handling this higher complexity. In this paper, the authors present a decentralized system built with a structured overlay network that is self-organized and self-healing, providing a transactional replicated storage for small or large scale systems.

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