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NIST Authors in Bold

Displaying 20451 - 20475 of 73960

A probabilistic approach for the analysis of stair evacuation movement data

January 1, 2014
Author(s)
Enrico Ronchi, Erica D. Kuligowski, Richard D. Peacock, Paul A. Reneke
This paper presents an innovative method to study stair evacuation data based on a probabilistic analysis of occupant travel paths. This type of approach relies on a detailed video analysis of people movement and pattern reconstruction. Conditional

Advanced Biaxial Cruciform Testing at the NIST Center for Automotive Lightweighting

January 1, 2014
Author(s)
Mark A. Iadicola, Adam A. Creuziger, Timothy J. Foecke
Modeling of sheet metal forming operations requires mechanical properties data at very large tensile strains and various biaxial strain paths. Typically these data are developed along strain ratio paths that are linear and monotonic, but actual forming

An Ordered Metallic-Glass Solid-Solution Phase That Grows From the Melt Like a Crystal

January 1, 2014
Author(s)
Lyle E. Levine, Karena Chapman, Leonid A. Bendersky, Gabrielle G. Long, John W. Cahn, Peter Chupas, Judith K. Stalick, Frederic Mompiou
We used high-energy synchrotron-based X-ray scattering to investigate the structure of an isotropic AlFeSi metallic glass that nucleates and grows from the melt during rapid cooling like a crystal. The glass is a noncrystalline homogeneous metastable phase

Atomic Scale Defects Associated with the Negative Bias Temperature Instability

January 1, 2014
Author(s)
Jason P. Campbell, P. M. Lenahan
We utilize magnetic resonance measurements to identify the fundamental atomic-scale defect structures involved in the negative bias temperature instability. In gate stacks composed of pure silicon dioxide, we find a degradation mechanism directly involving

Comparison of atom probe compositional fidelity across thin film interfaces

January 1, 2014
Author(s)
Andrew Herzing, Justin G. Brons, Karen T. Henry, Ian M. Anderson, Gregory B. Thompson
A series of Fe/Ni and Ti/Nb multilayers with bilayer repeat distances of approximately 4 nm have been sputter-deposited onto n-doped Si [001] substrates. The films were focus ion beam milled into the required needle-shaped geometry for atom probe analysis

Constraints on the Possible Long-Range Orbital Ordering in LaCoO 3

January 1, 2014
Author(s)
Daniel P. Phelan, Peter M. Gehring
A neutron powder diffraction measurement was performed to distinguish between the proposed monoclinic (I2/a) structure of LaCoO 3, which is consistent with orbital ordering, and the rhombohedral (R3c) structure, which is inconsistent with orbital ordering

Fast and Reliable Spectral Response Measurements of PV Cells Using Light Emitting Diodes

January 1, 2014
Author(s)
Behrang H. Hamadani, John F. Roller, Brian P. Dougherty, Howard W. Yoon
We present a measurement system for absolute differential spectral responsivity of solar cells based on high-powered LED arrays coupled to an optical light guide capable of large area illumination. Two different measurement techniques were developed and

Mapping the Local Photo-Electronic Properties of Polycrystalline Solar Cells through High Resolution Laser-Beam-Induced Current Microscopy

January 1, 2014
Author(s)
Marina S. Leite, Maxim Abashin, Henri J. Lezec, Anthony G. Gianfrancesco, Albert A. Talin, Nikolai B. Zhitenev
To boost the efficiency of thin film polycrystalline solar cells that are microscopically inhomogeneous, it is imperative to understand how the grain cores (GCs) and grain boundaries (GBs) within these materials affect its overall electronic properties. By

Materials Genome III: Building CALPHAD File and Data Repositories

January 1, 2014
Author(s)
Carelyn E. Campbell, Ursula R. Kattner, Zi-Kui Liu
The future development of the CALPHAD method requires establishing file and data repositories and tools to automate the modeling process and to enable efficient implementation of new models and development of multicomponent descriptions. To advance these

Measurement Traceability in Medical Physics

January 1, 2014
Author(s)
Lisa R. Karam
Medical physics, the joining of physics with healthcare, requires a level of quality assurance beyond many applications of the physical sciences. Always the health, and often the life, of the patient depends on the precise and accurate implementation of
Displaying 20451 - 20475 of 73960
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