An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
The National Institute of Standards and Technology coordinates the Micronutrients Measurement Quality Assurance Program (MMQAP) for laboratories that measure fat- and water-soluble vitamins and carotenoids in human serum and plasma. This report describes
This handbook compiles uniform laws and regulations developed by the Committee on Laws and Regulations of the National Conference on Weights and Measures (NCWM). This edition contains amendments adopted by the NCWM at its Annual Meeting in 2015. It
This handbook has been prepared as a procedural guide for the compliance testing of net contents statements on packaged goods. Compliance testing of packaged goods is the determination of the conformance results of the packaging, distribution, and
Tina Butcher, Linda D. Crown, Richard A. Harshman, Clark Cooney
Handbook 44 was first printed in 1949, having been preceded by similar handbooks of various designations and in several forms. This 2016 edition was developed by the Committee on Specifications and Tolerances of the National Conference on Weights and
Stephan Schlamminger, Jon R. Pratt, David B. Newell, Frank C. Seifert, Michael Liu, Leon S. Chao, Luis Manuel Pea Prez, Shisong Li, Darine El Haddad
Measurements of the Planck constant with watt balances using 1 kg masses have achieved relative standard uncertainties below 2 x 10-8. Having established a metrological link between the kilogram and this fundamental constant of nature, a redefinition of
This paper describes recent work in transitioning line scale measurements from an old LSI machine to a vision probe equipped Moore-M48 Coordinate Measuring Machine (CMM) based platform.
Ann C. Chiaramonti Debay, Stephanie L. Miller, Paul T. Blanchard, Erik A. Pfeif
Laser welding has significantly improved since its first commercial deployment in 1966, and is the preferred joining method when high weld quality, high production speed, and low thermal distortion are required. Laser welding (LW) encompasses a wide range
State and local weights and measures jurisdictions or other testing laboratories that use transfer standards developed using the air-oven reference methods (referred to as air-oven reference standards) to test commercial grain moisture meters, collect
Prem K. Rachakonda, Balasubramanian Muralikrishnan, Katharine M. Shilling, Geraldine S. Cheok, Vincent D. Lee, Christopher J. Blackburn, Dennis S. Everett, Daniel S. Sawyer
The Dimensional Metrology Group (DMG) at the National Institute of Standards and Technology (NIST) is performing research to support the development of documentary standards within ASTM E57 for the point-to-point performance evaluation of 3D imaging
Nicholas G. Paulter Jr., David M. Jenkins, Norimitsu Ichikawa, Michael Leonesio
Electroshock weapons (ESWs) have become a ubiquitous component of weapons used in the arsenal of domestic law enforcement (LE) agencies and the military around the world. It is a major contributor to the escalation of force policies and procedures of many
Alexander Tselev, Jeyavel Velmurugan, Andrei Kolmakov
The ability of the near-field microwave microscopy to image subsurface structures has been realized shortly after the invention of the technique. Based on these capabilities, we propose and successfully tested a novel concept of in situ near-field scanning
Walter B. Wilson, Lane C. Sander, M. J. Lopez de Alda, Milton Lee, Stephen A. Wise
Retention indices for 79 alkyl-substituted polycyclic aromatic sulfur heterocycles (PASHs) were determined by using reversed-phase liquid chromatography (LC) on a monomeric and polymeric octadecylsilane (C18) stationary phase. Molecular shape parameters
Walter B. Wilson, Lane C. Sander, M. J. Lopez de Alda, Milton Lee, Stephen A. Wise
Retention indices for 70 polycyclic aromatic sulfur heterocycles (PASHs) were determined using reversed-phase liquid chromatography (LC) on a monomeric and a polymeric C18 stationary phase. Molecular shape parameters [length, breadth, thickness (T), and
Jeyavel Velmurugan, Ana Stevanovic, Feng Yi, David A. LaVan, Andrei Kolmakov
Electrochemical techniques such as like electrodeposition are crucially important for fabrication of nanostructured materials. The details of cluster nucleation and growth at early stages of electrodeposition are extremely important for morphology and
Albert Davydov, Sergiy Krylyuk, Irina Kalish, Ryan Beams, Patrick Vora
We examine anharmonic contributions to the optical phonon frequency in bulk Td-MoTe2 phase through temperature-dependent Raman spectroscopy. At temperatures greater than 100 K we find that the optical phonon modes redshift linearly with temperature in
A number of scoring systems for proficiency testing and interlaboratory comparison are in use by the metrology community. The choice of scoring system for a given study is often based on the study coordinator's experience and anecdotal knowledge, perhaps
This report describes an equivalent volume measurement method using optical microscopy for estimating the mean volume of nominally 100 um diameter spherical droplets. The droplets are the aqueous phase of proprietary water in oil emulsions used in a
State level calculations are fundamental to extract any parameter of a time-domain waveform. Here we compare state level calculations using two different estimators, the histogram mode method and the shorth method. Our results show that both methods yield
Darine El Haddad, Leon S. Chao, Frank C. Seifert, David B. Newell, Jon R. Pratt, Stephan Schlamminger
In the past four years, we have constructed a new watt balance at the National Institute of Standards and Technology (NIST), with the goal to realize the unit of mass after the redefinition of the International System of Units, expected to occur in 2018
Yi-hua D. Tang, Frank C. Seifert, Stephan Schlamminger
A Programmable Josephson Voltage Standard (PJVS) system is used for the voltage measurements in NIST-4 Watt balance experiment. It is critical to enhance the leakage resistance of the PJVS in order to achieve the uncertainty of voltage measurements better
Dean G. Jarrett, Randolph Elmquist, Marlin E. Kraft, George R. Jones Jr., Shamith Payagala, Frank Seifert, Stephan Schlamminger, Darine El Haddad
Scaling from the quantum Hall resistance to 100 Ω standard resistors used by the NIST-4 Watt Balance involves multiple resistance standards and bridges to provide the lowest possible uncertainty. Described here is the infrastructure and procedures
Alessio Pollarolo, Horst Rogalla, Anna Fox, Kevin J. Coakley, Weston L. Tew, Samuel P. Benz
SPECTRAL ABERRATION HAS BEEN FOR A LONG TIME THE MAIN SOURCE OF UNCERTAINTY IN THE JOHNSON NOISE THERMOMETRY APPROACH TO MEASURING THE BOLTZMANN CONSTANT. RECENTLY, WITH NEWLY DEVELOPED HARDWARE AND THE INTRODUCTION OF A NOVEL FITTING ALGORITHM FOR
Xiaohai Cui, Yu S. Meng, Rolf Judaschke, Juergen Ruehaak, Thomas P. Crowley, Ronald A. Ginley
This paper reports preliminary measurement results of an informal international power comparison in WR15 (50 GHz to 75 GHz) waveguide among NIST, NIM, PTB and NMC, A*Star. The goal of the comparison was to demonstrate the precision measurement capabilities
Evgheni Strelcov, Anton Ievlev, Alex Belianinov, Alexander Tselev, Andrei A. Kolmakov, Sergei Kalinin
We report a synergistic approach of micro-Raman spectroscopic mapping and deep data analysis to study the distribution of crystallographic phases and ferroelastic domains in a defected Al-doped VO2 microcrystal. Bayesian linear unmixing revealed an uneven
Yong Sik Kim, Hongliang Shi, Nicholas Dagalakis, Satyandra K. Gupta
Conventional miniaturized motion stages have the volume of 50 to 60 cm3 and the range of motion around 100 µm. Micro-Electro-Mechanical Systems (MEMS)-based motion stages have been good alternatives in some applications for small foot print, micron-level