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Metrology

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Displaying 126 - 150 of 2756

Test Facility for Pressure Losses in Plumbing Pipes and Fittings

July 15, 2024
Author(s)
Lingnan Lin, Natascha S. Milesi-Ferretti, Glen A. Glaeser
This report describes a new test facility at NIST for the measurement of pressure losses in pipes and fittings used in plumbing systems. Pressure losses are fundamental inputs to the design of premise plumbing systems, yet the available technical data on

A unified model of core metrological concepts

July 10, 2024
Author(s)
David W. Flater, Raghu N. Kacker, Douglas Foxvog
The definitions of core metrological terms, especially quantity, quantity value, and unit, have been the subject of years of wrangling in standards organizations. A chronic disagreement exists over whether quantities are conceptualized primarily as

Redetermination of the Gravitational Constant using the BIPM Torsion Balance

July 8, 2024
Author(s)
Stephan Schlamminger, Leon Chao, David B. Newell, Vincent Lee, Clive Speake
For the past several years, we have been using the torsion balance developed at the Bureau International des Poids et Mesures (BIPM) to measure the gravitational constant $G$. The most notable feature of the apparatus is that it allows the measurement of

Entanglement kinetics in polymer melts are chemically specific

July 3, 2024
Author(s)
Benjamin Dolata
We investigate the universality of entanglement kinetics in polymer melts. We compare predictions of a recently developed constitutive equation for disentanglement to molecular dynamics simulations of both united-atom polyethylene and Kremer-Grest models

Flexures for Kibble balances: Minimizing the effects of anelastic relaxation

July 1, 2024
Author(s)
Lorenz Keck, Stephan Schlamminger, Rene Theska, Frank Seifert, Darine El Haddad
Modern weighing cells would not be possible without flexure technology. Flexures are thin metal strips that form pivots, and they can be engineered to bend in a prescribed fashion, producing a desired restoring torque. In contrast to other pivots, flexures

A Distributed Theory for Contactless Interconnects at Terahertz Frequencies

June 25, 2024
Author(s)
Nicholas Jungwirth, Bryan Bosworth, Aaron Hagerstrom, Meagan Papac, Eric Marksz, JEROME CHERON, Kassiopeia Smith, Angela Stelson, Ari Feldman, Dylan Williams, Nathan Orloff, Christian Long
Here we test a multimodal model for distributed contactless interconnects by comparing it to 3D full-wave simulations. In comparison to 3D simulations, the model offers insight into how the interconnect works and reduces the computational cost of

New Method to Probe the Surface Properties of Polymer Thin Films by Two-Dimensional (2D) Inverse Gas Chromatography (iGC)

June 25, 2024
Author(s)
Whirang Cho, Lucas Flagg, Christopher Stafford, Jeremiah Woodcock, Daniel Burnett, Anett Kondor, Douglas Fox, John Hoffmann
Polymer-based functional surface coatings are extensively used in advanced technologies, including optics, energy, and environmental applications. Surface thermodynamic properties profoundly impact the molecular interactions that control interfacial

A proposal to change the leap-second adjustments to UTC

June 3, 2024
Author(s)
Judah Levine, Patrizia TAVELLA
The definition of UTC in 1972 balanced the needs of the time and frequency community for a universal time scale that was traceable to the definition of frequency in the SI system of units with the needs of the astronomical community for a time scale that

Letter to the editor: Unit one is intrusive

May 24, 2024
Author(s)
David W. Flater
The SI brochure's treatment of quantities that it regards as dimensionless, with the associated unit one, requires certain physical quantities to be regarded as simply numbers. The resulting formal system erases the nature of these quantities and excludes

Standards and Metrology for Viral Vectors as Molecular Tools: Outcomes from a CCQM Workshop

May 24, 2024
Author(s)
Janathan Campbell, Neil Almond, Y Bae, Ravneet Bhuller, Andrea Briones, S-Y CHO, Megan Cleveland, Thomas Cleveland, Francis Galaway, Hua-Jun He, U Herbrand, Jim Huggett, Sarah Kempster, Ibolya Kepiro, Afifa Khan, Edward Kwee, Wilson Li, Sheng Lin-Gibson, Luise Luckau, Caterina Minelli, M Ryadnov, I Searing, Lili Wang, Alexandra Whale, Julian Braybrook
Viral vectors are agents enabling gene transfer and genome editing and have widespread utility across the healthcare and biotechnology sectors. In January 2023, the International Bureau for Weights and Measures' Consultative Committee for Amount of

Dual-comb correlation spectroscopy of thermal light

May 23, 2024
Author(s)
Eugene Tsao, Alexander Lind, Connor Fredrick, Ryan Cole, Peter Chang, Kristina Chang, Dahyeon Lee, Matthew Heyrich, Nazanin Hoghooghi, Franklyn Quinlan, Scott Diddams
The detection of light of thermal origin is the principal means by which humanity has learned about our world and the cosmos. In optical astronomy, in particular, direct detection of thermal photons and the resolution of their spectra have enabled

Recommendations on fit-for-purpose criteria to establish a quality management for microphysiological systems (MPS) and for monitoring of their reproducibility

May 14, 2024
Author(s)
David Pamies, Jason Ekert, Marie-Gabrielle Zurich, Olivier Frey, Sophie Werner, MONICA PIERGIOVANNI, Benjamin Freedman, Adrian Keong, Darwin Reyes-Hernandez, Hendrik Erfurth, Peter Loskill, Pelin Candarlioglu, Shan Wang, Thomas Hartung, Sandra Coecke, Glyn Stacey, Marcel Leist
Cell culture technology has seen great innovations and progress in the 21st centuryClassical single-cell and monolayer models have been replaced by more complex 3D models (e.g., reaggregates, spheroids, organoids) to improve the predictivity of in vitro

A 0.1 GHz to 1.1 THz Inverted Grounded-CPW mTRL Calibration Kit Characterization in an InP HBT Process

May 13, 2024
Author(s)
Jerome Cheron, Rob Jones, Dylan Williams, Miguel Urteaga, Bryan Bosworth, Nick Jungwirth, Jeffrey Jargon, Ben Jamroz, Chris Long, Nate Orloff, Ari Feldman, Peter Aaen
We report a novel design approach of on-wafer multiline thru-reflect-line (mTRL) calibration kit fabricated on a commercial semiconductor-based transistor process that we validate from 0.1 GHz to 1.1 THz. The on-wafer calibration standards are designed

Laser tracker and terrestrial laser scanner range error evaluation by stitching

May 7, 2024
Author(s)
Balasubramanian Muralikrishnan, Braden Czapla, Vincent Lee, Craig Shakarji, Daniel S. Sawyer, Saure Matthias
Laser trackers (LTs) are dimensional measurement instruments commonly employed in the manufacture and assembly of large structures. Terrestrial laser scanners (TLSs) are a related class of dimensional measurement instruments more commonly employed in

An Interlaboratory Study for Assessing Repeatability and Reproducibility of the Data Generated by Rotating Drum Powder Rheometers Part 1: Granudrum

May 3, 2024
Author(s)
Vipin Tondare, Justin Whiting, Adam L. Pintar, Shawn P. Moylan, Aurelien Neveu, Filip Francqui
The National Institute of Standards and Technology (NIST) organized an interlaboratory study to assess the repeatability and reproducibility of the data generated by two commercially available rotating drum powder rheometers namely, Granudrum and

Mechanism of action, potency and efficacy: considerations for cell therapies

May 2, 2024
Author(s)
Carl Simon, Anne Plant, Catherine Zander, Erich Bozenhardt, Christina Celluzzi, David Dobnik, Melanie Grant, John Hughes, Uma Lakshmipathy, Kok-Seong Lim, Laura Montgomery, Hesham Nawar, Thiana Nebel, Linda Peltier, James Sherley, Rouzbeh Taghizadeh, Eddie Tan, Sandrine Vessillier
Abstract One of the most challenging aspects of developing advanced cell therapy products (CTPs) is defining the mechanism of action (MOA), potency and efficacy of the product. This perspective examines these concepts and presents helpful ways to think

Operando XPS for Plasma Process Monitoring: A Case Study on the Hydrogenation of Copper Oxide Confined under h-BN

April 29, 2024
Author(s)
Trey Diulus, Andrew Naclerio, J. Anibal Boscoboinik, Ashley Head, Evgheni Strelcov, Piran Kidambi, Andrei Kolmakov
We demonstrate that ambient pressure x-ray photoelectron spectroscopy (APXPS) can be used for in situ studies of dynamic changes in surface chemistry in a plasma environment. Hexagonal boron nitride (h-BN) was used in this study as a model system since it

VDI/VDE 2634-2 and ISO 10360-13 Performance Evaluation Tests, and Systematic Errors in Structured Light Systems

April 29, 2024
Author(s)
Octavio Icasio Hernandez, Alex Rocha De La Cruz, Balasubramanian Muralikrishnan, Vincent Lee, Wei Ren, Jose-Joel Gonzalez-Barbosa
Structured light projection systems (SLSs) are commonly used for precision dimensional measurements. These are active systems in that the projected pattern is used to establish correspondence between the projector and the camera to provide more accurate 3D
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