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Search Publications

NIST Authors in Bold

Displaying 901 - 925 of 2606

Assessment of Conformity, Decision Rules and Risk Analysis

April 1, 2014
Author(s)
Steven D. Phillips, Michael Krystek
Measurement uncertainty has important economic consequences for calibration and inspection activities. In calibration reports, the magnitude of the uncertainty is often taken as an indication of the quality of the laboratory. In industrial measurements

Calibrating multiple microscopes with a smartphone

April 1, 2014
Author(s)
Peter Bajcsy, Mary C. Brady, Jacob Siegel
Summary: The iPhone liquid crystal displays allows efficient and accurate calibration of an inexpensive array of handheld microscopes for measuring microscopic dynamic events over a large field of view. How does one build an inexpensive array of handheld

Determination of the Planck constant using a watt balance with a superconducting magnet system at the National Institute of Standards and Technology

March 31, 2014
Author(s)
Stephan Schlamminger, Darine El Haddad, Frank C. Seifert, Leon S. Chao, David B. Newell, Richard L. Steiner, Jon R. Pratt
In the past two years measurements were performed with a watt balance at the National Institute of Standards and Technology (NIST) to determine the Planck constant. A detailed analysis of these measurements and their uncertainties led to a value of h=6.626

Report of the 98th National Conference on Weights and Measures (2013)

March 31, 2014
Author(s)
Linda D. Crown, Tina G. Butcher, Richard A. Harshman, David A. Sefcik, Lisa Warfield
The 98th Annual Meeting of the National Conference on Weights and Measures (NCWM) was held July 14 to 18, 2013, at the Seelbach Hilton Louisville, Louisville, Kentucky. The theme of the meeting was “On the Path to Tomorrow.” Reports by the NCWM Board of

Liquid Piston Prover Uncertainty Analysis Spreadsheet

March 25, 2014
Author(s)
John D. Wright, Aaron N. Johnson, Jodie G. Pope
This publication is a spreadsheet that calculates the mass and volume flow uncertainty for a piston prover liquid flow standard based on user inputs of component uncertainties. The calculations use the basis equation and uncertainty analysis presented in

Bootstrap Variability Studies in ROC Analysis on Large Datasets

March 19, 2014
Author(s)
Jin Chu Wu, Alvin F. Martin, Raghu N. Kacker
The nonparametric two-sample bootstrap is employed to compute uncertainties of measures in receiver operating characteristic (ROC) analysis on large datasets in areas such as biometrics, and so on. In this framework, the bootstrap variability was

Performance of Coriolis Meters in Transient Gas Flows

March 17, 2014
Author(s)
Jodie G. Pope, John D. Wright
NIST evaluated the instantaneous and totalized flow measured by two commercial coriolis meters under transient flow, pressure, and temperature conditions using a Transient Flow Facility (TFF) developed for this purpose. During a simulated cascade fill of a

Are Bragg Peaks Gaussian?

March 12, 2014
Author(s)
Boualem Hammouda
It is common practice to assume that Bragg scattering peaks have Gaussian shape. The Gaussian shape function is used to perform instrumental smearing corrections. Using Monte Carlo ray tracing simulation, the resolution of a realistic small-angle neutron

Controlled Formation and Characterization of Dithiothreitol-Conjugated Gold Nanoparticle Clusters

March 5, 2014
Author(s)
De-Hao D. Tsai, Tae Joon Cho, Frank W. DelRio, Justin Gorham, Jiwen Zheng, Jiaojie Tan, Michael R. Zachariah, Vincent A. Hackley
We report a systematic study of the controlled formation of discrete-size gold nanoparticle clusters (GNCs) by interaction with the reducing agent dithiothreitol (DTT). Asymmetric-flow field flow fractionation and electrospray differential mobility

How to weigh everything from atoms to apples using the revised SI

March 3, 2014
Author(s)
Jon R. Pratt
The fact that the unit of mass might soon be derived from the Planck constant, rather than from an artifact standard, can seem daunting and downright baffling when viewed from the vantage point of our day to day perception of mass. After all, at

Certification of Total Arsenic in Blood and Urine Standard Reference Materials by Radiochemical Neutron Activation Analysis and Inductively Coupled Plasma Mass Spectrometry

March 1, 2014
Author(s)
Rick L. Paul, William C. Davis, Karen E. Murphy, Colleen E. Bryan Sallee, Lee L. Yu, William F. Guthrie, Dennis D. Leber, Thomas W. Vetter
A newly developed procedure for determination of arsenic by radiochemical neutron activation analysis was used to measure arsenic in SRM 955c Toxic Elements in Caprine Blood and SRM 2668 Toxic Elements in Frozen Human Urine for the purpose of providing

Methods for improving visibility measurement standards of powered industrial vehicles

February 28, 2014
Author(s)
Roger V. Bostelman, Jochen Teizer, Soumitry J. Ray, Mike Agronin, Dominic Albanese
Poor visibility of powered industrial vehicles, such as forklifts, used in industry is often the cause of accidents that include pedestrians. Current standards allow up to 20% non-visible regions for forklifts where measurement of these regions is

In situ temperature measurements for selective epitaxy of GaN nanowires

February 17, 2014
Author(s)
Kristine A. Bertness, Matthew D. Brubaker, Todd E. Harvey, Shannon M. Duff, Aric W. Sanders, Norman A. Sanford
We demonstrate with spatially resolved, in situ temperature measurements and ex situ reflectance measurements that differences in appearance for masked and unmasked surfaces on patterned growth substrates arise from wavelength-dependent emissivity

Metrological challenges introduced by new tolerancing standards

February 13, 2014
Author(s)
Ed Morse, Yue Peng, Vijay Srinivasan, Craig M. Shakarji
The recent release of ISO has provided designers with a richer set of specification tools for the size of part features, so that various functional requirements can be captured with greater fidelity [2]. However, these tools also bring new challenges and

Estimation of uncertainty in application profiles

February 3, 2014
Author(s)
David W. Flater
Application profiling tools are the instruments used to measure software performance at the function and application levels. The most powerful measurement method available in application profiling tools today is sampling-based profiling, where a

Estimation of the Limit of Detection Using Information Theory Measures

January 31, 2014
Author(s)
Alexander (. Vergara Tinoco, Fonollosa Jordi, Huerta Ramon, Santiago Marco
Definitions of the Limit of Detection (LoD) based on the probability of false positive and/or false negative errors have been proposed over the past years. Although such definitions are straightforward and valid for any kind of analytical system, the
Displaying 901 - 925 of 2606