scholarly journals A hybrid molecular dynamics/fluctuating hydrodynamics method for modelling liquids at multiple scales in space and time

2015 ◽  
Vol 143 (1) ◽  
pp. 014110 ◽  
Author(s):  
Ivan Korotkin ◽  
Sergey Karabasov ◽  
Dmitry Nerukh ◽  
Anton Markesteijn ◽  
Arturs Scukins ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Multiple Scales ◽  
Fluctuating Hydrodynamics ◽  
Space And Time

scholarly journals Visualising and controlling the flow in biomolecular systems at and between multiple scales: from atoms to hydrodynamics at different locations in time and space

2014 ◽  
Vol 169 ◽  
pp. 285-302 ◽  
Author(s):  
Evgen Pavlov ◽  
Makoto Taiji ◽  
Arturs Scukins ◽  
Anton Markesteijn ◽  
Sergey Karabasov ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Force Feedback ◽  
Multiple Scales ◽  
Biomolecular Systems ◽  
Space And Time ◽  
Statistical Continuum ◽  
Dynamics Simulations ◽  
Purpose Computer ◽  
Special Purpose Computer ◽  
The Continuum

A novel framework for modelling biomolecular systems at multiple scales in space and time simultaneously is described. The atomistic molecular dynamics representation is smoothly connected with a statistical continuum hydrodynamics description. The system behaves correctly at the limits of pure molecular dynamics (hydrodynamics) and at the intermediate regimes when the atoms move partly as atomistic particles, and at the same time follow the hydrodynamic flows. The corresponding contributions are controlled by a parameter, which is defined as an arbitrary function of space and time, thus, allowing an effective separation of the atomistic ‘core’ and continuum ‘environment’. To fill the scale gap between the atomistic and the continuum representations our special purpose computer for molecular dynamics, MDGRAPE-4, as well as GPU-based computing were used for developing the framework. These hardware developments also include interactive molecular dynamics simulations that allow intervention of the modelling through force-feedback devices.

Language, Race, and Reflexivity

2020 ◽  
pp. 23-46
Author(s):  
Adrienne Lo ◽  
Elaine Chun
Keyword(s):  
United States ◽  
Racial Discrimination ◽  
Multiple Scales ◽  
The United States ◽  
Linguistic Differences ◽  
Space And Time

This chapter reviews research on language and race in the United States, concentrating on two paradigms of research: research focused on linguistic differences and racial discrimination and research focused on ideologies and racialization. It examines several thorny conceptual issues that arise in the first paradigm and that specifically relate to the notion of the ‘ethnolect’, including their labeling, distinctiveness, authenticity, and multidimensionality. It also argues for the importance of a reflexive approach that entails looking at racialized language as an ideological construct and situating processes of racialization across multiple scales of space and time and within structures of power. Such an approach recognizes how processes of racialization, which take place in both scholarly and everyday contexts, often prioritize the perspectives and interests of certain people over those of others.

scholarly journals The application of centre-manifold theory to the evolution of system which vary slowly in space

1988 ◽  
Vol 29 (4) ◽  
pp. 480-500 ◽  
Author(s):  
A. J. Roberts
Keyword(s):  
Multiple Scales ◽  
Limited Range ◽  
Future Research ◽  
Centre Manifold ◽  
Space And Time ◽  
Physical Problems ◽  
Formal Procedure ◽  
Slow Evolution ◽  
Manifold Theory ◽  
Correction Terms

AbstractIn many physical problems, the system tends quickly to a particular structure, which then evolves relatively slowly in space and time. Various methods exist to derive equations describing the slow evolution of the particular structure; for example, the method of multiple scales. However, the resulting equations are typically valid only for a limited range of the parameters. In order to extend the range of validity and to improve the accuracy, correction terms must be found for the equations. Here we describe a procedure, inspired by centre-manifold theory, which provides a systematic approach to calculating a sequence of successively more accurate approximations to the evolution of the principal structure in space and time.The formal procedure described here raises a number of questions for future research. For example: what sort of error bounds can be obtained, do the approximations converge or are they strictly asymptotic, and what sort of boundary conditions are appropriate in a given problem?

Multiscale Model Validation Based on Generalized Interval Bayes’ Rule and its Application in Molecular Dynamics Simulation

2014 ◽  
Author(s):  
Aaron E. Tallman ◽  
Joel D. Blumer ◽  
Yan Wang ◽  
David L. McDowell
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Model Validation ◽  
Multiple Scales ◽  
Epistemic Uncertainty ◽  
Measurement Data ◽  
Dynamics Simulation ◽  
Bayes Rule ◽  
State Variables ◽  
Interval Probability

Reliable simulation protocols supporting integrated computational materials engineering requires uncertainty to be quantified. In general, two types of uncertainties are recognized. Aleatory uncertainty is inherent randomness, whereas epistemic uncertainty is due to lack of knowledge. Aleatory and epistemic uncertainties need to be differentiated in validating multiscale models, where measurement data for unconventionally very small or large systems are scarce, or vary greatly in forms and quality (i.e. sources of epistemic uncertainty). In this paper, a recently proposed generalized hidden Markov model is used for cross-scale and cross-domain information fusion under the two types of uncertainties. The dependency relationships among the observable and hidden state variables at multiple scales and physical domains are captured using generalized interval probability. The update of imprecise credence and model validation are based on a generalized interval Bayes’ rule. Its application in molecular dynamics simulation for irradiation of Fe is demonstrated.

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