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.
Nadine Guillaume, Walter K. Kahn, Richard A. Allen, Michael W. Cresswell, Mona E. Zaghloul
This paper describes a novel approach to the application of conformal mapping to capacitance evaluation. A particular structure composed of an array of identical lines and located below a conductive plate is studied. Results show that the application of
Precise AE signal arrival times of the fundamental Lamb modes can be obtained from the arrival time of the peak wavelet transform (WT) magnitude at a particular frequency of interest. Since these arrival times are not determined from a fixed threshold
… waveforms. In the case of Ni-Mo alloys produced by pulse plating, the composition, morphology and current efficiency … density was significantly reduced for both DC and pulsed plating. Even with the increased Mo 6+ concentration, the current efficiency for DC plating remained below 10%. The morphology was particularly …
Jifeng Qu, Samuel Benz, Kevin Coakley, Horst Rogalla, Weston L. Tew, David R. White, Kunli Zhou, Zhenyu Zhou
Recent measurements using acoustic gas thermometry have determined the value of the Boltzmann constant, k, with a relative uncertainty less than 110-6. These results have been supported by a measurement with a relative uncertainty of 1.910-6 made with
Michael R. Moldover, Roberto M. Gavioso, David B. Newell
We review correlated uncertainties among the accurate determinations of the Boltzmann constant kB that used the techniques of primary acoustic gas thermometry (AGT). We consider uncertainty contributions from four sources: (1) resonator-dependent
Stephan Schlamminger, Darine El Haddad, Frank C. Seifert, Leon S. Chao, David B. Newell, Ruimin Liu, Richard L. Steiner, Jon R. Pratt
In 2013, a new measurement of the Planck constant h was performed using a watt balance at the National Institute of Standards and Technology (NIST). The value is h=6.626 069 79(30) x 10^{-34} J s. The relative standard uncertainty of this determination is
In this homepage, the history, construction, design and calibration of proving rings are given. The importance of force measurement and the principles involved are described.
Randolph Elmquist, Neil M. Zimmerman, William Huber
We propose an experiment with some advantages over other direct quantum metrology triangle comparisons. First, by using a cryogenic resistor that can be calibrated, the QHR standard needs to be used only for short periods. Second, the experiment does not
The National Bureau of Standards Reactor at the NIST Center for Neutron Research (NCNR) is a 20 MW reactor using 93% enriched UO 2 plate-type fuel with D 2O coolant, moderator, and reflector, and is used for a variety of neutron science applications. 23 of
The strength degrading effects of sharp-contact damage are examined for Y-TZP ceramic plates bonded to a plastic substrate. Microscale contacts are made with Vickers and Berkovich diamond indenters at low loads (0.01 N to 10 N) in the ceramic lower
A stack of quasi-randomly oriented quartz plates has been assembled as a calibration artifact for mode-coupled polarization-mode dispersion. The design of the artifact, the reasons for choosing it, the procedure for its assembly, and its implementation are
The amplitudes of shear horizontal plate waves generated by EMATs (electromagnetic acoustic transducers) are measured to obtain estimated of the magnetostriction of a steel specimen. The wave amplitude is linked to magnetrostriction through an existing
Many advanced plasma diagnostic techniques and plasma models require fundamental physical data in order to make accurate measurements or predictions. Fundamental electron-interaction data are among the most critical since electron collisions are the