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Dive into the research topics where Darine Haddad is active.

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Featured researches published by Darine Haddad.


Metrologia | 2014

Determination of the Planck constant using a watt balance with a superconducting magnet system at the National Institute of Standards and Technology

Stephan Schlamminger; Darine Haddad; F. Seifert; L.S. Chao; David B. Newell; Ruimin Liu; Richard L. Steiner; Jon R. Pratt

For the past two years, measurements have been performed with a watt balance at the National Institute of Standards and Technology (NIST) to determine the Planck constant. A detailed analysis of these measurements and their uncertainties has led to the value h = 6.626 069 79(30) × 10−34 J s. The relative standard uncertainty is 45 × 10−9. This result is 141 × 10−9 fractionally higher than h90. Here h90 is the conventional value of the Planck constant given by , where KJ-90 and RK-90 denote the conventional values of the Josephson and von Klitzing constants, respectively.


IEEE Transactions on Instrumentation and Measurement | 2014

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

F. Seifert; Alireza Panna; Shisong Li; Bing Han; L.S. Chao; Austin Cao; Darine Haddad; Heeju Choi; Lori Haley; Stephan Schlamminger

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 Technology, a permanent magnet system was chosen. We describe the detailed construction of the magnet system, first measurements of the field profile, and shimming techniques that were used to achieve a flat field profile. The relative change of the radial magnetic flux density is <; 10-4 over a range of 5 cm. We further characterize the most important aspects of the magnet and give order of magnitude estimates for several systematic effects that originate from the magnet system.


Metrologia | 2015

A summary of the Planck constant measurements using a watt balance with a superconducting solenoid at NIST

Stephan Schlamminger; Richard L. Steiner; Darine Haddad; David B. Newell; F. Seifert; L.S. Chao; Ruimin Liu; Edwin R. Williams; Jon R. Pratt

Researchers at the National Institute of Standards and Technology have been using a watt balance, NIST-3, to measure the Planck constant


Metrologia | 2016

Coil motion effects in watt balances: a theoretical check

Shisong Li; Stephan Schlamminger; Darine Haddad; F. Seifert; L.S. Chao; Jon R. Pratt

h


IEEE Transactions on Instrumentation and Measurement | 2015

First Measurements of the Flux Integral With the NIST-4 Watt Balance

Darine Haddad; F. Seifert; L.S. Chao; Austin Cao; George Sineriz; Jon R. Pratt; David B. Newell; Stephan Schlamminger

for over ten years. Two recently published values disagree by more than one standard uncertainty. The motivation for the present manuscript is twofold. First, we correct the latest published number to take into account a recently discovered systematic error in mass dissemination at the Bureau International des Poids et Mesures (BIPM). Second, we provide guidance on how to combine the two numbers into one final result. In order to adequately reflect the discrepancy, we added an additional systematic uncertainty to the published uncertainty budgets. The final value of


IEEE Transactions on Instrumentation and Measurement | 2015

A Determination of the Local Acceleration of Gravity for the NIST-4 Watt Balance

Eric J. Leaman; Darine Haddad; F. Seifert; L.S. Chao; Austin Cao; Jon R. Pratt; Stephan Schlamminger; David B. Newell

h


IEEE Transactions on Instrumentation and Measurement | 2009

Balance Pan Damping Using Rings of Tuned Sloshing Liquids

Edwin R. Williams; Darine Haddad; G. Geneves; Pierre Gournay; Christian Hauck; F. Villar; Richard L. Steiner; Ruimin Liu

measured with NIST-3 is


conference on precision electromagnetic measurements | 2014

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

Darine Haddad; L.S. Chao; F. Seifert; David B. Newell; Jon R. Pratt; Stephan Schlamminger

h = 6.626\,069\,36(37)\times 10^{-34}\,\mbox{J\,s}


conference on precision electromagnetic measurements | 2008

Progress on the LNE watt balance project

G. Geneves; Pierre Gournay; F. Villar; Darine Haddad; C. Hauck; M. Wakim; Paul-André Meury; Tanguy Madec; P. Pinot; P. Juncar; S. Merlet; F. Pereira Dos Santos; Jean-Marie David; Luc Chassagne; Suat Topcu

. This result is


conference on precision electromagnetic measurements | 2012

Low noise programmable current source for the NIST-3 and NIST-4 watt balance

Darine Haddad; Bryan C. Waltrip; Richard L. Steiner

77(57) \times 10^{-9}

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Stephan Schlamminger

National Institute of Standards and Technology

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Jon R. Pratt

National Institute of Standards and Technology

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David B. Newell

National Institute of Standards and Technology

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F. Seifert

Czech Technical University in Prague

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L.S. Chao

National Institute of Standards and Technology

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Ruimin Liu

National Institute of Standards and Technology

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G. Geneves

Conservatoire national des arts et métiers

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Richard L. Steiner

National Institute of Standards and Technology

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Edwin R. Williams

National Institute of Standards and Technology

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P. Juncar

Conservatoire national des arts et métiers

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