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Displaying 1 - 25 of 2606

Test Facility for Pressure Losses in Plumbing Pipes and Fittings

July 15, 2024
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
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

Entanglement kinetics in polymer melts are chemically specific

July 3, 2024
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

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

June 25, 2024
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

Letter to the editor: Unit one is intrusive

May 24, 2024
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

Dual-comb correlation spectroscopy of thermal light

May 23, 2024
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

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

May 13, 2024
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

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

May 3, 2024
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

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

April 29, 2024
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

Self-Assembly of Hierarchical High-h Fluorinated Block Copolymers with an Orthogonal Smectic-within-Lamellae 3 nm Sub-Lattice and Vertical Surface Orientation

April 16, 2024
Bijal Patel, Hongbo Feng, Whitney Loo, Chad R. Snyder, Christopher Eom, Julia Murphy, Daniel Sunday, Paul Nealey, Dean DeLongchamp
Hierarchical structure-within-structure assemblies offer a route toward increasingly complex and multifunctional materials while pushing the limits of block copolymer self-assembly. We present a detailed study of the self-assembly of a series of

Comparison of a 1 nF Capacitor with a 1 kO Resistor Using a Digital Impedance Bridge

March 27, 2024
Yicheng Wang, Stephan Schlamminger, Dean G. Jarrett, Alireza Panna, Andrew D. Koffman
This paper reports our effort to improve a digital impedance bridge. The limit of the bridge resolution and stability is less than 3 parts in 10^9 for the nominal 1:1 impedance comparison of two 100 pF capacitors. The type-A uncertainty for comparison of a

Certification Approaches for Weigh-In-Motion Systems in Law Enforcement Applications

March 26, 2024
Katrice Lippa, Jan Konijnenburg, Loren Minnich, Tanvi Pandya, James Willis
Every day, overweight and excessively heavy vehicles cause damage to roads, bridges, and other vehicle-based infrastructure. To protect this vital transportation infrastructure for the U.S., states have imposed weight limits for commercial and fleet

Excited-Band Coherent Delocalization for Improved Optical Lattice Clock Performance

March 24, 2024
Jacob Siegel, Andrew Ludlow, Youssef Hassan, Kyle Beloy, Tanner Grogan, Chun-Chia Chen
We implement coherent delocalization as a tool for improving the two primary metrics of atomic clock performance: systematic uncertainty and instability. By decreasing atomic density with co- herent delocalization, we suppress cold-collision shifts and two

Discover STEM Education Resources

March 6, 2024
Cara O'Malley, Elizabeth Benham
The National Institute of Standards & Technology (NIST) invites educators to discover STEM resources on the NIST Educational STEM Resource (NEST-R) registry! Published by NIST scientists, engineers, & staff, NEST-R content is free & publicly available. It

Uniform Laws and Regulations in the Areas of Legal Metrology and Fuel Quality

March 5, 2024
John McGuire, David Sefcik, Lisa Warfield, Yvonne Branden, Katrice Lippa
NIST Handbook 130 includes a compilation of model laws and regulations and related interpretations and guidelines designed to encourage uniformity in adoption and implementation of weights and measures laws and regulations. The model laws and regulations

A Common Data Dictionary and Common Data Model for Additive Manufacturing

February 16, 2024
Alexander Kuan, Kareem Aggour, Shengyen Li, Yan Lu, Luke Mohr, Alex Kitt, Hunter Macdonald
Additive manufacturing (AM) leverages emerging technologies and well-adopted processes to produce near-net-shape products. The advancement of AM technology requires data management tools to collect, store and share information through the product

Practical realisation of the kelvin by Johnson noise thermometry

February 15, 2024
Horst Rogalla, D Rod White, Jifeng Qu, Samuel P. Benz, Christof Gaiser, Weston L. Tew, Nathan Flowers-Jacobs, Kevin J. Coakley, Alessio Polarollo, Chiharu Urano
Johnson noise thermometry (JNT) is a purely electronic method of thermodynamic thermometry. In primary JNT, the temperature is inferred from a comparison of the Johnson noise voltage of a resistor at the unknown temperature with a pseudo-random noise

Application of Electrical Standards to Torque Realization: A Device to Measure up to 1Nm

February 14, 2024
Zane Comden, Stephan Schlamminger, Frank Seifert, David B. Newell, Leon Chao
This paper describes the next generation prototype of the Electronic NIST Torque Realizer (ENTR) project. The first prototype version (ENTR-v1) has been able to realize low-range torques (on the order of 1×10-3 Nm) to uncertainties of less than 1000 parts
Displaying 1 - 25 of 2606