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Metrology

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Displaying 276 - 300 of 2728

Characterizing Frequency Stability Measurements having Multiple Data Gaps

February 2, 2022
Author(s)
David A. Howe, Noah Schlossberger
Time series measurements with data gaps (dead times) prevent accurate computations of frequency variances such as the Allan variance (AVAR) and its square-root ADEV. To extract frequency distributions, data must be sequentially ordered and equally spaced

New reference materials for trace-levels of actinide elements in plutonium

January 27, 2022
Author(s)
Richard Essex, Lav Tandon, Amy Gaffney, Cole Hexel, Debbie Bostick, Lisa Colletti, Diana Decker, Casey Finstad, Joseph Giaquinito, Elmer Lujan, John Partridge, Benjamin Roach, John Rolinson, Kyle Samperton, Alice Slemmons, Khalil Spencer, Floyd Stanley, Lisa Townsend, Kerri Treinen, Ross Williams, Christopher Worley
Two plutonium oxides were prepared as unique reference materials for actinides occurring as trace constituents in Pu. Each reference material unit is approximately 200 mg of PuO2 in a quartz glass vial. Characterized attributes of the oxides included mass

Quantitative Determination of Cell Viability Using Absorbance Microscopy

January 19, 2022
Author(s)
Greta Babakhanova, Stephen Zimmerman, Laura Pierce, Sumona Sarkar, Nicholas Schaub, Carl Simon Jr.
Cell viability is an essential measurement for cell therapy products. One of the most common tests is Trypan blue (TB) dye exclusion where blue-stained cells are counted via imaging. Typically, live and dead cells are counted based on pixel intensities of

AbsorbanceQ: An App for Generating Absorbance Images from Brightfield Images

January 4, 2022
Author(s)
Stephen Zimmerman, Carl Simon Jr., Greta Babakhanova
The AbsorbanceQ app converts brightfield microscope images into absorbance images that can be analyzed and compared across different operators, microscopes and time. Absorbance-based measurements are comparable, which is useful when the aim is to

Mixture model analysis of Transition Edge Sensor pulse height spectra

December 9, 2021
Author(s)
Kevin J. Coakley, Jolene D. Splett, Thomas Gerrits
To calibrate an optical transition edge sensor, for each pulse of the light source (e.g., pulsed laser), one must determine the ratio of the expected number of photons that deposit energy and the expected number of photons created by the laser. Based on

HDX-MS and MD simulations provide evidence for stabilization of the IgG1- FcgRIa (CD64a) immune complex through intermolecular glycoprotein bonds

December 8, 2021
Author(s)
Kyle Anderson, Kerry Scott, Christina Bergonzo, Ioannis Karageorgos, Elyssia Gallagher, Venkata Tayi, Michael Butler, Jeffrey W. Hudgens
Previous reports present different models for the stabilization of the Fc—FcγRI immune complex. Although accord exists on the importance of L235 in IgG1 and some hydrophobic contacts for complex stabilization, discord exists regarding the existence of

A Comparison of Particle Size Distribution and Morphology Data acquired using Lab-based and Commercially Available Techniques: Application to Stainless Steel Powder

November 17, 2021
Author(s)
Justin Whiting, Edward Garboczi, Vipin Tondare, John Henry J. Scott, Alkan Donmez, Shawn P. Moylan
The particle size distribution (PSD) and particlemorphology ofmetal powders undoubtedly affects the quality of parts produced by additivemanufacturing (AM). It is, therefore, crucial to accurately knowthe PSD and morphology of these powders. There exist

Unified Parameterization and Calibration of Serial, Parallel, and Hybrid Manipulators

November 17, 2021
Author(s)
Josh Gordon, Benjamin Moser, Ben Moser, Andrew Petruska
In this work, we present methods allowing parallel, hybrid, and serial manipulators to be analyzed, calibrated, and controlled with the same analytical tools. We introduce a general approach to describe any robotic manipulator using established serial-link

MICROMETROLOGY IN PURSUIT OF QUANTUM RADIATION STANDARDS

November 9, 2021
Author(s)
Ryan P. Fitzgerald, Zeeshan Ahmed, Denis E. Bergeron, Nikolai Klimov, Dan Schmidt, Ronald Tosh
With the recent redefinition of the SI base units in terms of constants of nature, the race is on to maximize achievable precision by developing primary standards based on quantum metrology, thereby to realize the Quantum SI. For the becquerel (Bq) and

Time-series Imputation Algorithm

November 5, 2021
Author(s)
David A. Howe, Chloe Champagne
Statistical imputation is a field of study that attempts to fill missing data. It is commonly applied to population statistics whose data have no correlation with running time. For a time series, data is typically analyzed using the autocorrelation, the

A Resilient Architecture for the Realization and Distribution of Coordinated Universal Time to Critical Infrastructure Systems in the United States: Methodologies and Recommendations from the National Institute of Standards and Technology (NIST)

November 3, 2021
Author(s)
Jeffrey Sherman, Ladan Arissian, Roger Brown, Matthew J. Deutch, Elizabeth Donley, Vladislav Gerginov, Judah Levine, Glenn Nelson, Andrew Novick, Bijunath Patla, Tom Parker, Benjamin Stuhl, Jian Yao, William Yates, Michael A. Lombardi, Victor Zhang, Douglas Sutton
The Time and Frequency Division of the National Institute of Standards and Technology (NIST), an agency of the United States Department of Commerce (DOC), was tasked with fulfilling Section 4, Part (i) of the Position, Navigation and Timing (PNT) Executive

A Dynamic Uncertainty Protocol for Digital Sensor Networks

November 1, 2021
Author(s)
Michael Gaitan, Richard A. Allen, Jon Geist, Akobuije Chijioke
We propose a concept of the use of dynamic uncertainty to improve the accuracy and robustness of digital sensor networks. The digital smart transducer is integrated with a microcontroller that reads the binary data from the calibrated sensor, performs an
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