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Displaying 1026 - 1050 of 2957

First mass measurements with the NIST-4 watt balance

July 10, 2016
Author(s)
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

Coil motion effects in watt balances: a theoretical check

February 10, 2016
Author(s)
Stephan Schlamminger, Shisong Li, Darine El Haddad, Frank C. Seifert, Leon S. Chao, Jon R. Pratt
A watt balance is a precision apparatus for the measurement of the Planck constant that has been proposed as a primary method for realizing the unit of mass in a revised International System of Units. In contrast to an ampere balance, which was

A significant-loophole-free test of Bell's theorem with entangled photons

December 16, 2015
Author(s)
Marissa Giustina, Marijn Versteegh, Soren Wengerowsky, Johannes Handsteiner, Armin Hochrainer, Kevin Phelan, Fabian Steinlechner, Johannes Koffler, Larsson Jan-Ake, Carlos Abellan, Waldimar Amaya, Valerio Pruneri, Morgan Mitchell, Joern Beyer, Thomas Gerrits, Adriana Lita, Krister Shalm, Sae Woo Nam, Thomas Scheidl, Rupert Ursin, Bernhard Wittmann, Anton Zeilinger
Local realism is the worldview in which physical properties of objects exist independently of measurement and where physical influences cannot travel faster than the speed of light. Bell's theorem states that this worldview is incompatible with the

Construction of a watt balance with the aim to realize the kilogram at the National Institute of Standards and Technology

August 1, 2014
Author(s)
Darine El Haddad, Leon Chao, Frank Seifert, David B. Newell, Jon R. Pratt, Stephan Schlamminger
A redefinition of the International System of Units, the SI, is impending and could occur as early as 2017. After redefinition a means to realize the unit of mass is required. A watt balance is a promising device to realize the unit of mass at the kilogram

Experimental test of an event-based corpuscular model modification as an alternative to quantum mechanics

February 13, 2013
Author(s)
Giorgio Brida, Ivo P. Degiovanni, Marco Genovese, Alan L. Migdall, Fabrizio Piacentini, Sergey Polyakov, Paola Traina
We present the first experimental test that distinguishes between an Event-Based Corpuscular Model (EBCM)9) of the interaction of photons with matter and quantum mechanics. The test looks at the interference that results as a single photon passes through a

Optimizing Acoustic Measurements of the Boltzmann Constant

November 22, 2009
Author(s)
Michael R. Moldover
We review the progress in acoustic metrology of gases that has occurred since the 1988 measurement of the universal gas constant R using a spherical acoustic resonator. The advances in understanding resonators and in calculating the thermophysical

Electron Self-Energy for the K and L Shells at Low Nuclear Charge

April 1, 2001
Author(s)
U Jentschura, Peter J. Mohr, G Soff
A nonperturbative numerical evaluation of the one-photon electron self energy for the K- and L-shell states of hydrogen like ions with nuclear charge numbers Z = 1 to 5 is described. Our calculation for the 1S 1/2 state has a numerical uncertainty of 0.8

A Result from the NIST Watt Balance and an Analysis of Uncertainties

April 1, 1999
Author(s)
Richard L. Steiner, David B. Newell, Edwin R. Williams
An improved determination of the ratio of power, measured in terms of the Josephson and quantum Hall effects, and also the meter, kilogram, and second, has been completed. The result is expressed as: W 90/W = 1 + (8187) x 10 -9. This is an order of

An Accurate Measurement of Planck's Constant

July 1, 1998
Author(s)
Edwin R. Williams, Richard L. Steiner, David B. Newell
Using a moving coil watt balance, electric power measured in terms of the Josephson and quantum Hall effects is compared with mechanical power measured in terms of the meter, kilogram and second, we find the Planck constant h = 6.62606891(58) x 10 -34 Js

Concrete Rheology: Knowledge and Challenges?

September 13, 2006
Author(s)
Chiara F. Ferraris
The design of concrete with specified properties for an application is not a new science, but it has taken on a new meaning with the wide use of special concretes, such as self compacting concrete (SCC). General terms such as flow under its own weight and

Recent Advances in Fire-Structure Analysis

February 1, 2008
Author(s)
Dat Duthinh, Kevin B. McGrattan, Abed M. Khaskia
One of the recommendations of the National Construction Safety Team for the Federal Building and Fire Safety Investigation of the World Trade Center Disaster (NIST NCSTAR 1, 2005) is to enhance the capability of available computational software to predict

MSEL FY 2001 Programs and Accomplishments: Metallurgy Division

September 1, 2001
Author(s)
C A. Handwerker, Frank W. Gayle, Richard E. Ricker
This report describes major programs and accomplishments of the Metallurgy Division of the NIST Materials Science and Engineering Laboratory (MSEL) in FY2001 The mission of the NIST Metallurgy Division is to provide critical leadership in the development

Metallurgy Division 2000 Programs and Accomplishments

January 1, 2001
Author(s)
C A. Handwerker, Robert J. Schaefer
This report describes major programs and accomplishments of the Metallurgy Division of the NIST Materials Science and Engineering Laboratory (MSEL) in FY2000.The mission of the NIST Metallurgy Division is to provide critical leadership in the development

Vacuum-Gap Capacitors for Low-Loss Superconducting Resonant Circuits

June 16, 2009
Author(s)
Katarina Cicak, Michael S. Allman, Joshua Strong, Kevin Osborn, Raymond W. Simmonds
Low-loss microwave components are used in many superconducting resonant circuits from multiplexed readouts of low-temperature detector arrays to quantum bits. Two-level system (TLS) defects in amorphous dielectric materials cause excess energy loss. In an

Extended EUV and UV Spectrum of Ne II

July 1, 2006
Author(s)
Alexander Kramida, C M. Brown, Uri Feldman, Joseph Reader
The extreme ultraviolet (EUV) spectrum of Ne emitted by a Penning discharge has been recorded at high resolution with a 10.7 m grazing incidence spectrometer. Based on the recorded spectra 75 new Ne II lines have been observed between 286 and 325

Size-Monodisperse Metal Nanoparticles Via Hydrogen-Free Spray Pyrolysis

April 3, 2002
Author(s)
Jung Hyeun Kim, Thomas A. Germer, George Mulholland, S H. Ehrman
Pure copper nanoparticles were produced using a co-solvent approach avoiding use of hydrogen or other reducing gas. Compared with the particles formed without the co-solvent, the addition of alcohol has a significant effect in preventing oxidation, which

A Phase-Field Model of Convection with Solidification

January 1, 2002
Author(s)
D M. Anderson, Geoffrey B. McFadden, A A. Wheeler
A phase-field model for the solidification of a pure material that incorporates convection has recently been developed. This model is a two-fluid model in which the solid phase is modeled as a sufficiently viscous fluid. The model allows for the solid and
Displaying 1026 - 1050 of 2957
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