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Search Publications by Jon R. Pratt

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Displaying 1 - 25 of 111

Contributions of precision engineering to the revision of the SI

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

Bridging classical and quantum mechanics

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

Milligram mass metrology using an electrostatic force balance

Author(s)
Gordon A. Shaw, Julian Stirling, John A. Kramar, Alexander D. Moses, Patrick J. Abbott, Richard L. Steiner, Andrew D. Koffman, Jon R. Pratt, Zeina J. Kubarych
Although mass is typically defined within the International System of Units (SI) at the Kilogram level, the pending redefinition of the SI provides an

Design of a Table-Top Watt Balance

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

First mass measurements with the NIST-4 watt balance

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

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

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

Coil motion effects in watt balances: a theoretical check

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

Optomechanical reference accelerometer

Author(s)
Oliver Gerberding, Felipe Guzman, John T. Melcher, Jon R. Pratt, Jacob M. Taylor
We present an opto-mechanical accelerometer device with high dynamic range, high bandwidth and readout noise levels exceeding 10 μg/√Hz . The straightforward

Optomechanical Motion Sensors

Author(s)
Felipe Guzman, Oliver Gerberding, John T. Melcher, Julian Stirling, Jon R. Pratt, Gordon A. Shaw, Jacob M. Taylor
Compact optical cavities can be combined with motion sensors to yield unprecedented resolution and SI-traceability in areas such as acceleration sensing and

The Redefinition of the SI: Impact on Calibration Services at NIST

Author(s)
Neil M. Zimmerman, Jon R. Pratt, Michael R. Moldover, David B. Newell, Gregory F. Strouse
As most readers are probably at least vaguely aware, it is likely that the SI system of units will be redefied in 2018. This redefinition would fundamentally

First measurements of the flux integral with the new NIST-4 watt balance

Author(s)
Darine El Haddad, Frank C. Seifert, Leon S. Chao, Yusi A. Cao, Georgio A. Sineriz, Jon R. Pratt, David B. Newell, Stephan Schlamminger
In early 2014, construction of a new watt balance, named NIST-4, has started at the National Institute of Standards and Technology (NIST). In a watt balance

A constant from a mass, a mass from a constant

Author(s)
Jon R. Pratt, Stephan Schlamminger, David B. Newell, Leon S. Chao, Zeina J. Kubarych, Patrick J. Abbott, Yusi A. Cao, Frank C. Seifert, Darine El Haddad
NIST recently used a watt balance instrument known as NIST-3 to measure the Planck constant in terms of IPK with a relative uncertainty of approximately 45

Alignment and testing of the NIST Calculable Capacitor

Author(s)
Yicheng Wang, Felipe Guzman, Corey A. Stambaugh, Radek Smid, Hugo Zuniga Calvo, Andrew D. Koffman, Jon R. Pratt, John R. Lawall
This paper reports progress on the NIST effort to develop a new calculable capacitor, focusing on improvement of the guard electrode motion control as well as

Construction and Performance of the NIST-4 Magnet System

Author(s)
Frank C. Seifert, Alireza R. Panna, Leon S. Chao, Yusi A. Cao, Darine El Haddad, Shisong Li, Stephan Schlamminger, Jon R. Pratt, Heeju Choi, Lori Haley
A watt balance is a promising instrument to realize the unit of mass at the kilogram level. The magnet system is one of the key elements of such an instrument

The Design of the NEW NIST-4 Watt Balance

Author(s)
Leon S. Chao, Stephan Schlamminger, Frank C. Seifert, Yusi A. Cao, Darine El Haddad, David B. Newell, Jon R. Pratt
The design of the new permanent-magnet driven watt balance and novel mechanical features will demonstrate the high-precision capabilities of a large complex

Heterodyne interferometer with subnanometer accuracy

Author(s)
Darine El Haddad, Frank C. Seifert, Stephan Schlamminger, Leon S. Chao, David B. Newell, Jon R. Pratt
This paper gives a brief description of the laser interferometer system designed for the next generation watt balance experiment aimed to realize the unit of