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Search Publications by Darine El Haddad

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Displaying 1 - 25 of 27

The Design and Development of a Tabletop Kibble Balance at NIST

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

The Kibble balance and the kilogram

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

The Design and Development of a Tabletop Kibble Balance at NIST

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

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

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

Quantum Hall Resistance Traceability for the NIST-4 Watt Balance

Author(s)
Dean G. Jarrett, Randolph E. Elmquist, Marlin E. Kraft, George R. Jones, 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

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

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

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

Construction, Measurement, Shimming, and Performance of the NIST-4 Magnet System

Author(s)
Frank C. Seifert, Alireza R. Panna, Leon S. Chao, Bing Han, Shisong Li, Yusi A. Cao, Darine El Haddad, Stephan Schlamminger, Heeju Choi, Lori Haley
The magnet system is one of the key elements of a watt balance. For the new watt balance currently under construction at the National Institute of Standards and