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Search Publications by: Stephan Schlamminger (Fed)

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Displaying 26 - 50 of 74

Basic Metrology for 2020

April 30, 2020
Author(s)
Stephan Schlamminger, Richard Davis
2019 was a big year for Metrology. The international system of units was revised on World Metrology Day, May 20th, that year [1]. What will 2020 bring? In this article we discuss five promising advances that we have on a watchlist for 2020. First, we

The Design and Development of a Tabletop Kibble Balance at NIST

May 23, 2019
Author(s)
Leon S. Chao, Frank C. Seifert, Darine El Haddad, Julian Stirling, David B. Newell, Stephan Schlamminger
On November 16, 2018, the 26th General Conference on Weights and Measures (CGPM) voted unanimously to revise the International System of Units (SI) from a system built on seven base units to one built on seven defining constants and will officially become

The Kibble balance and the kilogram

March 25, 2019
Author(s)
Stephan Schlamminger, Darine El Haddad
Dr. Bryan Kibble invented the watt balance in 1975 to improve the realization of the unit for electrical current, the ampere. With the discovery of the Quantum Hall e ect in 1980 by Dr. Klaus von Klitzing and in conjunction with the previously predicted

The Design and Development of a Tabletop Kibble Balance at NIST

March 20, 2019
Author(s)
Leon S. Chao, Frank C. Seifert, Darine El Haddad, Stephan Schlamminger
A global paradigm shift to redefine the International System of Units (SI) from a system based on seven fundamental units to seven fundamental constants is well under way. More specifically, the unit of mass, the kilogram, will be realized via a fixed

A new magnet design for future Kibble balances

April 4, 2018
Author(s)
Stephan Schlamminger, Shisong Li, Michael Stock
We propose a new permanent magnet system for Kibble balance experiments, which combines advantages of the magnet designs invented by the National Physical Laboratory (NPL) and by the Bureau International des Poids et Mesures (BIPM). The goal of the

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

A precise instrument to determine the Planck constant, and the future kilogram

June 21, 2016
Author(s)
Darine El Haddad, Frank C. Seifert, Leon S. Chao, David B. Newell, Jon R. Pratt, Carl J. Williams, Stephan Schlamminger, Shisong Li
A precise instrument, called a 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 link between mechanical action and the Planck

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

Schwere Experimente

November 1, 2015
Author(s)
Stephan Schlamminger, Christian Rothleitner
Obwohl die Standardunsicherheit der Gravitationskonstante in der neuesten Veröffentlichung des CODATA um über die Hälfte reduziert wurde, ist sie noch immer die am ungenauesten bestimmte Naturkonstante.