The role of the international prototype of the kilogram after redefinition of the International System of Units

Davis, Richard

doi:10.1098/rsta.2011.0181

Cited by 8 publications

(8 citation statements)

References 21 publications

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“…In order to minimize serious consequences from such a hypothetical situation, CCM made its recommendations cited above [37]. A pertinent example that the change in definitions of the mole and kilogram will have no consequences in testing physical laws is provided by an experimental test of Einstein's mass-energy relation, as discussed in Appendix B of [55].…”

Section: Review Of Selected Papers and Summary Of Key Issues Raised Bmentioning

confidence: 99%

A critical review of the proposed definitions of fundamental chemical quantities and their impact on chemical communities (IUPAC Technical Report)

Marquardt

Meija

Mester

et al. 2017

Pure and Applied Chemistry

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Abstract:In the proposed new SI, the kilogram will be redefined in terms of the Planck constant and the mole will be redefined in terms of the Avogadro constant. These redefinitions will have some consequences for measurements in chemistry. The goal of the Mole Project (IUPAC Project Number 2013-048-1-100) was to compile published work related to the definition of the quantity 'amount of substance', its unit the 'mole', and the consequence of these definitions on the unit of the quantity mass, the kilogram. The published work has been reviewed critically with the aim of assembling all possible aspects in order to enable IUPAC to judge the adequateness of the existing definitions or new proposals. Compilation and critical review relies on the broadest spectrum of interested IUPAC members.

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Section: Review Of Selected Papers and Summary Of Key Issues Raised Bmentioning

confidence: 99%

A critical review of the proposed definitions of fundamental chemical quantities and their impact on chemical communities (IUPAC Technical Report)

Marquardt

Meija

Mester

et al. 2017

Pure and Applied Chemistry

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“…The IPK and a group of the prototypes were inter‐compared originally around 1890, for the second time in 1948, and for the third time in 1990. By the third verification, it became obvious that the relative mass differences between the IPK, the témoins, and others were spreading over time even though the materials, storage, and usage were all similar, see Figure . Further, these relative differences suggested that the IPK itself was changing in mass by comparable or larger amounts; because except for its definition, it was just another cylinder of PtIr.…”

Section: Introductionmentioning

confidence: 97%

The Planck Constant for the Definition and Realization of the Kilogram

Wood

Bettin

2018

Annalen der Physik

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On May 20, 2019 the values of the Planck, h, and Avogadro, N A , constants will be fixed, revising our measurement system, the International System of Units (SI), and providing a new way to get mass traceability. While the famous energy relations mc 2 and hf may remind many that the Planck constant is indeed related to mass, it is less recognized how this is also true for the Avogadro constant. These concepts are reviewed in the context of the upcoming revision of the SI. How the fixed values were chosen and how mass traceability will be maintained with the smallest uncertainty are also discussed.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/andp.201800308 ν Cs = 9 192 631 770 Hz hyperfine transition frequency of 133 Cs c = 299 792 458 m s −1 speed of light in vacuum h = 6.626 070 15 × 10 −34 J s Planck constant e = 1.602 176 634 × 10 −19 C elementary charge k = 1.380 649 × 10 −23 J K −1 Boltzmann constant N A = 6.022 140 76 × 10 23 mol −1 Avogadro constant K cd = 683 lm W −1 luminous efficacy of 540 × 10 12 Hz radiationThe values and use of c, ν Cs , and K cd are already established within the SI and this has made the change more manageable.

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“…Although defining the kilogram by fixing the value of the Planck constant is conceptually more complex than, for example, defining the kilogram in terms of the mass of the electron or a specified atom, the other advantages of fixing the value of the Planck constant make this the preferable definition. See also the paper by Bordé [13], as well as those of Becker & Bettin [14], Stock [15] and Davis [16] in this issue.…”

Section: Choosing the Fundamental Constants To Be Used In The Definitmentioning

confidence: 99%

Adapting the International System of Units to the twenty-first century

Mills

Mohr

Quinn

et al. 2011

Phil. Trans. R. Soc. A.

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We review the proposal of the International Committee for Weights and Measures (Comité International des Poids et Mesures, CIPM), currently being considered by the General Conference on Weights and Measures (Conférences Générales des Poids et Mesures, CGPM), to revise the International System of Units (Le Système International d'Unitès, SI). The proposal includes new definitions for four of the seven base units of the SI, and a new form of words to present the definitions of all the units. The objective of the proposed changes is to adopt definitions referenced to constants of nature, taken in the widest sense, so that the definitions may be based on what are believed to be true invariants. In particular, whereas in the current SI the kilogram, ampere, kelvin and mole are linked to exact numerical values of the mass of the international prototype of the kilogram, the magnetic constant (permeability of vacuum), the triple-point temperature of water and the molar mass of carbon-12, respectively, in the new SI these units are linked to exact numerical values of the Planck constant, the elementary charge, the Boltzmann constant and the Avogadro constant, respectively. The new wording used expresses the definitions in a simple and unambiguous manner without the need for the distinction between base and derived units. The importance of relations among the fundamental constants to the definitions, and the importance of establishing a mise en pratique for the realization of each definition, are also discussed.

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The role of the international prototype of the kilogram after redefinition of the International System of Units

Cited by 8 publications

References 21 publications

A critical review of the proposed definitions of fundamental chemical quantities and their impact on chemical communities (IUPAC Technical Report)

A critical review of the proposed definitions of fundamental chemical quantities and their impact on chemical communities (IUPAC Technical Report)

The Planck Constant for the Definition and Realization of the Kilogram

Adapting the International System of Units to the twenty-first century

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