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Displaying 26 - 50 of 175

Isotope Dilution Mass Spectrometry as an Independent Assessment for Mass Measurements of Milligram Quantities of Aqueous Solution

January 1, 2023
Author(s)
Richard Essex, Jacqueline L. Mann, Denis E. Bergeron, Ryan P. Fitzgerald, Svetlana Nour, Gordon A. Shaw, R. Michael Verkouteren
Isotope dilution mass spectrometry was used to independently assess the accuracy of mass measurement methods developed to quantitatively dispense milligram quantities of aqueous solution. Solutions of isotopically enriched 158Gd and enriched 155Gd were

Report of the 104th National Conference on Weights and Measures

May 3, 2021
Author(s)
Yvonne Branden
The 104th Annual Meeting of the National Conference on Weights and Measures (NCWM) was held July 14 - 18, 2019, at the Hyatt Regency Milwaukee Hotel, Milwaukee, Wisconsin. The theme of the meeting was "Assuring Equity in the Marketplace: NIST and NCWM

Design of an electrostatic balance to measure optical power of 100 kW

February 19, 2021
Author(s)
Lorenz Keck, Gordon A. Shaw, Renee Theska, Stephan Schlamminger
To accommodate the need for increased portability and accuracy in laser power measurement instrumentation above 100 Watt at the National Institute of Standards and Technology (NIST), a new instrument is required. This instrument is intended to create a new

Redefining the kilogram and other SI units

February 10, 2021
Author(s)
Stephan Schlamminger
Units are at the heart of science and technology. Most measurements require units to express their result. The International System of Units (SI) provides a widely used coherent framework of units. While the present SI is fit for purpose for all

Reports of The National Conference on Weights and Measures 1905 - 2019

January 15, 2021
Author(s)
Yvonne Branden
This is a compilation of the meetings of the National Conference on Weights and Measures (NCWM) for the years 1905 to 2019. Reports by the NCWM Board of Directors, Standing Committees, and Special Purpose Committees constitute the major portion of this

Simplified kilogram traceability for photon momentum radiometers

October 1, 2020
Author(s)
Kyle A. Rogers, Paul A. Williams, Gordon A. Shaw, John H. Lehman
High power laser applications in areas such as laser processing of materials can require an accurately measured laser power. Radiation pressure-based laser power measurement has been proven as a practical method for quantifying these high-power levels in

Report of the 104th National Conference on Weights and Measures

August 27, 2020
Author(s)
Yvonne A. Branden, Tina G. Butcher, Richard A. Harshman, Lisa Warfield, Gloria D. Lee, John W. Barton
The 104th Annual Meeting of the National Conference on Weights and Measures (NCWM) was held July 14 - 18, 2019, at the Hyatt Regency Milwaukee Hotel, Milwaukee, Wisconsin. The theme of the meeting was "Assuring Equity in the Marketplace: NIST and NCWM

Comparison of three essential submicron aerosol measurements: mass, size and shape

May 28, 2020
Author(s)
Qi Yao, Akua Asa-Awuku, Christopher D. Zangmeister, James Radney
An instrumental trifecta now exists for aerosol separation and classification by mobility diameter (Dm), aerodynamic diameter (Dae) and mass (mp) utilizing a differential mobility analyzer (DMA), aerodynamic aerosol classifier (AAC) or aerosol particle

Basic Metrology for 2020

April 30, 2020
Author(s)
Stephan Schlamminger, Richard Davis
2019 was a big year for Metrology. The international system of units was revised on World Metrology Day, May 20th, that year [1]. What will 2020 bring? In this article we discuss five promising advances that we have on a watchlist for 2020. First, we
Displaying 26 - 50 of 175