scholarly journals Critical conditions for failure; stress levels, length scales, time scales

2017 ◽  
Author(s):  
N. K. Bourne ◽  
G. T. Gray ◽  
C. A. Bronkhorst
Keyword(s):  
Time Scales ◽  
Failure Stress ◽  
Critical Conditions ◽  
Length Scales ◽  
Stress Levels

scholarly journals Scale-Selective Precision for Weather and Climate Forecasting

2019 ◽  
Vol 147 (2) ◽  
pp. 645-655 ◽  
Author(s):  
Matthew Chantry ◽  
Tobias Thornes ◽  
Tim Palmer ◽  
Peter Düben
Keyword(s):  
Time Scales ◽  
Weather Forecasting ◽  
Forecast Accuracy ◽  
Spectral Space ◽  
Dynamical Equations ◽  
Length Scales ◽  
Climate Forecasting ◽  
Spectral Models ◽  
Weather And Climate ◽  
Numerical Precision

Abstract Attempts to include the vast range of length scales and physical processes at play in Earth’s atmosphere push weather and climate forecasters to build and more efficiently utilize some of the most powerful computers in the world. One possible avenue for increased efficiency is in using less precise numerical representations of numbers. If computing resources saved can be reinvested in other ways (e.g., increased resolution or ensemble size) a reduction in precision can lead to an increase in forecast accuracy. Here we examine reduced numerical precision in the context of ECMWF’s Open Integrated Forecast System (OpenIFS) model. We posit that less numerical precision is required when solving the dynamical equations for shorter length scales while retaining accuracy of the simulation. Transformations into spectral space, as found in spectral models such as OpenIFS, enact a length scale decomposition of the prognostic fields. Utilizing this, we introduce a reduced-precision emulator into the spectral space calculations and optimize the precision necessary to achieve forecasts comparable with double and single precision. On weather forecasting time scales, larger length scales require higher numerical precision than smaller length scales. On decadal time scales, half precision is still sufficient precision for everything except the global mean quantities.

Hydration Dynamics at Femtosecond Time Scales and Angstrom Length Scales from Inelastic X-Ray Scattering

2009 ◽  
Vol 103 (23) ◽  
Author(s):  
Robert H. Coridan ◽  
Nathan W. Schmidt ◽  
Ghee Hwee Lai ◽  
Rahul Godawat ◽  
Michael Krisch ◽  
...  
Keyword(s):  
Time Scales ◽  
Length Scales ◽  
X Ray ◽  
X Ray Scattering ◽  
Hydration Dynamics ◽  
Ray Scattering

Failure Stress Levels of Flaws in Pressurized Cylinders

1973 ◽  
pp. 461-481 ◽  
Author(s):  
J. F. Kiefner ◽  
W. A. Maxey ◽  
R. J. Eiber ◽  
A. R. Duffy
Keyword(s):  
Failure Stress ◽  
Stress Levels

scholarly journals ONSET OF SHEAR WAVES IN A BACTERIAL BATH: A NOVEL EFFECT

2003 ◽  
Vol 03 (04) ◽  
pp. L373-L377 ◽  
Author(s):  
SUPURNA SINHA
Keyword(s):  
Time Scales ◽  
Shear Waves ◽  
Particle Diffusion ◽  
Length Scales ◽  
Structural Ordering ◽  
Propagating Shear

Recent experiments on particle diffusion in bacterial baths indicate the formation of correlated structures in the form of bacterial swirls. Here we predict that such a structural ordering would give rise to the new effect of propagating shear waves in a bacterial bath at length scales of the order of a swirl, which corresponds to time scales of the order of the lifetime of a swirl. Our prediction can be tested against future experiments in bacterial baths.

Numerical modeling of multiple length scales in thermal transport processes

2014 ◽  
Vol 24 (4) ◽  
pp. 781-796 ◽  
Author(s):  
Yogesh Jaluria
Keyword(s):  
Numerical Modeling ◽  
Boundary Conditions ◽  
Time Scales ◽  
Transport Processes ◽  
Thermal Processes ◽  
Length Scales ◽  
Content Type ◽  
Multiple Length Scales ◽  
Wide Range ◽  
Simulation Results

Purpose – Multiple length and time scales arise in a wide variety of practical and fundamental problems. It is important to obtain accurate and validated numerical simulation results, considering the different scales that exist, in order to predict, design and optimize the behavior of practical thermal processes and systems. The purpose of this paper is to present modeling at the different length scales and then addresses the question of coupling the different models to obtain the overall model for the system or process. Design/methodology/approach – Both numerical and experimental methods to obtain results at the different length scales, particularly at micro and nanoscales, are considered. Even though the paper focusses on length scales, multiple time scales lead to similar concerns and are also considered. The two circumstances considered in detail are multiple length scales in different domains and those in the same domain. These two cases have to be modeled quite differently in order to obtain a model for the overall process or system. The basic considerations involved in such a modeling are discussed. A wide range of thermal processes are considered and the methods that may be used are presented. The models employed must be validated and the accuracy of the simulation results established if the simulation results are to be used for prediction, control and design. Findings – Of particular interest are concerns like verification and validation, imposition of appropriate boundary conditions, and modeling of complex, multimode transport phenomena in multiple scales. Additional effects such as viscous dissipation, surface tension, buoyancy and rarefaction that could arise and complicate the modeling are discussed. Uncertainties that arise in material properties and in boundary conditions are also important in design and optimization. Large variations in the geometry and coupled multiple regions are also discussed. Research limitations/implications – The paper is largely focussed on multiple-scale considerations in thermal processes. Both numerical modeling/simulation and experimentation are considered, with the latter being used for validation and physical insight. Practical implications – Several examples from materials processing, environmental flows and electronic systems, including data centers, are given to present the different techniques that may be used to achieve the desired level of accuracy and predictability. Originality/value – Present state of the art and future needs in this interesting and challenging area are discussed, providing the impetus for further work. Different methods for treating multiscale problems are presented.

scholarly journals The nature and origin of the Barrovian metamorphism, Scotland: diffusion length scales in garnet and inferred thermal time scales

2011 ◽  
Vol 168 (1) ◽  
pp. 115-132 ◽  
Author(s):  
Daniel R. Viete ◽  
Jörg Hermann ◽  
Gordon S. Lister ◽  
Iona R. Stenhouse
Keyword(s):  
Time Scales ◽  
Diffusion Length ◽  
Thermal Time ◽  
Length Scales

scholarly journals Frictional dynamics of finger pads are governed by four length-scales and two time-scales

2016 ◽  
Author(s):  
Brygida Dzidek ◽  
Serena Bochereau ◽  
Simon Johnson ◽  
Vincent Hayward ◽  
Michael Adams
Keyword(s):  
Time Scales ◽  
Length Scales

scholarly journals Nanosecond timing and synchronization scheme for holographic pump–probe studies at the MID instrument at European XFEL

2021 ◽  
Vol 28 (3) ◽  
Author(s):  
Markus Osterhoff ◽  
Malte Vassholz ◽  
Hannes Paul Hoeppe ◽  
Juan Manuel Rosselló ◽  
Robert Mettin ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Visible Light ◽  
Time Scales ◽  
Single Pulse ◽  
Trigger System ◽  
Length Scales ◽  
Pump Probe ◽  
Holographic Imaging ◽  
Synchronization Scheme ◽  
Better Than

Single-pulse holographic imaging at XFEL sources with 1012 photons delivered in pulses shorter than 100 fs reveal new quantitative insights into fast phenomena. Here, a timing and synchronization scheme for stroboscopic imaging and quantitative analysis of fast phenomena on time scales (sub-ns) and length-scales (≲100 nm) inaccessible by visible light is reported. A fully electronic delay-and-trigger system has been implemented at the MID station at the European XFEL, and applied to the study of emerging laser-driven cavitation bubbles in water. Synchronization and timing precision have been characterized to be better than 1 ns.

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