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Search Publications by: Stephan Schlamminger (Fed)

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Displaying 76 - 100 of 157

Measurements of the Newtonian Constant of Gravitation, G

November 30, 2017
Author(s)
Christian Rothleitner, Stephan Schlamminger
The Newtonian Constant of Gravitation G seems to be the fundamental constant that is most difficult to measure accurately. In the past three decades more than a dozen precision measurements were performed. Unfortunately the scatter of the data points is

Contributions of precision engineering to the revision of the SI

November 28, 2017
Author(s)
Stephan Schlamminger, Harald Bosse, Horst Kunzmann, Jon R. Pratt, Ian Robinson, Michael de Podesta, Paul Shore, Paul Morantz
All measurements performed in science and industry are based on the International System of Units, the SI. It has been proposed to revise the SI following an approach which had already been implemented for the redefinition of the unit of length, the metre

Measurement of the Planck constant at the National Institute of Standards and Technology from 2015 to 2017

July 28, 2017
Author(s)
Darine El Haddad, Frank Seifert, Leon Chao, Antonio Possolo, David B. Newell, Jon R. Pratt, Carl J. Williams, Stephan Schlamminger
Researchers at the National Institute of Standards and Technology(NIST) estimate the value of the Planck constant as h = 6.62606994(10) x 10^-34 Js, hence with relative standard uncertainty 15.3 x 10^-9. This measurement result is based on over 17,000

Sizing up the Quantum

June 2, 2017
Author(s)
Stephan Schlamminger
No abstract. This is a column in Nature science.

Bridging classical and quantum mechanics

September 28, 2016
Author(s)
Darine El Haddad, Frank C. Seifert, Leon S. Chao, Shisong Lee, David B. Newell, Jon R. Pratt, Carl J. Williams, Stephan Schlamminger
Using a watt balance and a frequency comb, a mass-energy equivalence is derived. The watt balance compares mechanical power measured in terms of the meter, the second, and the kilogram to electrical power measured in terms of the volt and the ohm. A direct

Design of a Table-Top Watt Balance

July 26, 2016
Author(s)
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

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

Improvement of Leakage Resistance of PJVS for NIST-4 Watt Balance Experiment

July 10, 2016
Author(s)
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

Quantum Hall Resistance Traceability for the NIST-4 Watt Balance

July 10, 2016
Author(s)
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