Open Access. Powered by Scholars. Published by Universities.®

Physics Commons™

Open Access. Powered by Scholars. Published by Universities.®

2004

Selected Works

Engineering

Articles 1 - 5 of 5

Full-Text Articles in Physics

Asymptotic Accuracy Of Geoacoustic Inversions, Michele Zanolin, Ian Ingram, Aaron Thode, Nicholas C. Makris Sep 2004

Asymptotic Accuracy Of Geoacoustic Inversions, Michele Zanolin, Ian Ingram, Aaron Thode, Nicholas C. Makris

Michele Zanolin

Criteria necessary to accurately estimate a set of unknown geoacoustic parameters from remote acoustic measurements are developed in order to aid the design of geoacoustic experiments. The approach is to have estimation error fall within a specified design threshold by adjusting controllable quantities such as experimental sample size or signal-to-noise ratio (SNR). This is done by computing conditions on sample size and SNR necessary for any estimate to have a variance that (1) asymptotically attains the Cramer–Rao lower bound (CRLB) and (2) has a CRLB that falls within the specified design error threshold. Applications to narrow band deterministic signals received …

Go to article

Microscale Simulation Of Martensitic Microstructure Evolution, Valery I. Levitas, Alexander V. Idesman, Dean L. Preston Sep 2004

Microscale Simulation Of Martensitic Microstructure Evolution, Valery I. Levitas, Alexander V. Idesman, Dean L. Preston

Valery I. Levitas

A new model for the evolution of multivariant martensitic microstructure in single crystals and polycrystals is developed. In contrast with Landau-Ginzburg models, which are limited in practice to nanoscale specimens, this new scale-free model is valid for length scales greater than 100 nm and without an upper bound. It is based on a thermodynamic potential in the volume fractions of the martensitic variants that exhibits an instability resulting in microstructure formation. Simulated microstructures in elastic single crystals and polycrystals under uniaxial loading are in qualitative agreement with those observed experimentally.

Go to article

Reliable First-Principles Alloy Thermodynamics Via Truncated Cluster Expansions, Nikolai A. Zarkevich, Duane D. Johnson Jun 2004

Reliable First-Principles Alloy Thermodynamics Via Truncated Cluster Expansions, Nikolai A. Zarkevich, Duane D. Johnson

Nikolai A. Zarkevich

In alloys cluster expansions (CE) are increasingly used to combine first-principles electronicstructure calculations and Monte Carlo methods to predict thermodynamic properties. As a basis-set expansion in terms of lattice geometrical clusters and effective cluster interactions, the CE is exact if infinite, but is tractable only if truncated. Yet until now a truncation procedure was not well defined and did not guarantee a reliable truncated CE. We present an optimal truncation procedure for CE basis sets that provides reliable thermodynamics. We then exemplify its importance in Ni3V, where the CE has failed unpredictably, and now show agreement to a range of …

Go to article

Hypothetical Thermodynamic Properties: The Boiling And Critical Temperatures Of Polyethylene And Polytetrafluoroethylene, James S. Chickos Jan 2004

Hypothetical Thermodynamic Properties: The Boiling And Critical Temperatures Of Polyethylene And Polytetrafluoroethylene, James S. Chickos

James Chickos

No abstract provided.

Go to article

Science And Engineering Of Nanoparticle-Polymer Composites: Insights From Computer Simulation, Francis W. Starr, Sharon C. Glotzer Dec 2003

Science And Engineering Of Nanoparticle-Polymer Composites: Insights From Computer Simulation, Francis W. Starr, Sharon C. Glotzer

Francis Starr

No abstract provided.

Go to article