Measurement of the universal gas-constant R using a spherical acoustic resonator

Moldover, Michael R.; Trusler, J. P. Martin; Edwards, T.J.; Mehl, James B.; Davis, Richard

doi:10.6028/jres.093.010

Cited by 242 publications

(360 citation statements)

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“…The most innovative technique is the measurement of the volume of the resonator using electromagnetic microwaves. The corresponding contribution to the uncertainty is of a completely different nature from that of the pyknometry used by Moldover et al [1]. The microwave technique requires an accurate model involving the geometry of the resonator, the perturbations from antennas and the penetration of microwaves into the copper shell.…”

Section: Principle Of Measurementmentioning

confidence: 99%

“…The main improvements with respect to the previous determination [1] come from temperature measurements and molar mass of gas measurements. The most innovative technique is the measurement of the volume of the resonator using electromagnetic microwaves.…”

Section: Principle Of Measurementmentioning

confidence: 99%

“…The value is deduced from measurements of the velocity of sound in argon, as in the work performed by Moldover et al at the National Institute of Standards and Technology (NIST) in 1988 [1]. However, several fundamental modifications and improvements have been made to measure and control the parameters that influence the measurement of k B [2,3].…”

Section: Introductionmentioning

confidence: 99%

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Determination of the Boltzmann constant using a quasi-spherical acoustic resonator

Pitre

Sparasci

Truong

et al. 2011

Phil. Trans. R. Soc. A.

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The paper reports a new experiment to determine the value of the Boltzmann constant, k B = 1.3806477(17) × 10 −23 J K −1 , with a relative standard uncertainty of 1.2 parts in 10 6 . k B was deduced from measurements of the velocity of sound in argon, inside a closed quasispherical cavity at a temperature of the triple point of water. The shape of the cavity was achieved using an extremely accurate diamond turning process. The traceability of temperature measurements was ensured at the highest level of accuracy. The volume of the resonator was calculated from measurements of the resonance frequencies of microwave modes. The molar mass of the gas was determined by chemical and isotopic composition measurements with a mass spectrometer. Within combined uncertainties, our new value of k B is consistent with the 2006 Committee on Data for Science and Technology (CODATA) value: (k new B /k B_CODATA − 1) = −1.96 × 10 −6 , where the relative uncertainties are u r (k new B ) = 1.2 × 10 −6 and u r (k B_CODATA ) = 1.7 × 10 −6 . The new relative uncertainty approaches the target value of 1 × 10 −6 set by the Consultative Committee on Thermometry as a precondition for redefining the unit of the thermodynamic temperature, the kelvin.

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Section: Principle Of Measurementmentioning

confidence: 99%

Section: Principle Of Measurementmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Determination of the Boltzmann constant using a quasi-spherical acoustic resonator

Pitre

Sparasci

Truong

et al. 2011

Phil. Trans. R. Soc. A.

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“…44 All weighings were carried out on a precision electronic balance (Mettler Toledo, model PR5003) with a standard uncertainty of 5 mg. Values of the sinker volume at other temperatures and pressures were calculated from the relation…”

Section: Vibrating-wire and Sinker Propertiesmentioning

confidence: 99%

Viscosities and Densities of Binary Mixtures of Hexadecane with Dissolved Methane or Carbon Dioxide at Temperatures from (298 to 473) K and at Pressures up to 120 MPa

2016

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We report measurements of the viscosity and density of two binary mixtures comprising hexadecane with dissolved carbon dioxide or methane over the temperature range from (298.15 to 473.15) K and at pressures up to 120 MPa. The measurements were conducted at various mole fractions x of the light component as follows: x = (0, 0.0690, 0.5877 and 0.7270) for xCO2 + (1 -x)C16H34 and x = (0, 0.1013, 0.2021, 0.2976 and 0.3979) for xCH4 + (1 -x)C16H34. The viscosity and density measurements were carried out simultaneously using a bespoke vibrating-wire apparatus with a suspended sinker. With respect to the first mixture, the apparatus was operated in a relative mode and was calibrated in octane whereas, for the second mixture, the apparatus was operated in an absolute mode. To facilitate this mode of operation, the diameter of the centreless-ground tungsten wire was measured with a laser micrometer, and the mass and volume of the sinker were measured independently by hydrostatic weighing. In either mode of operation, the expanded relative uncertainties at 95 % confidence were 2 % for viscosity and 0.3 % for density. The results were correlated using simple relations that express both density and viscosity as functions of temperature and pressure. For both pure hexadecane and each individual mixture, the results have been correlated using the modified Tait equation for density, and the Tait-Andrade equation for viscosity; both correlations described our data almost to within their estimated uncertainties.In an attempt to model the viscosity of the binary mixtures as a function of temperature, density and composition, we have applied the extended-hard-sphere model using several mixing rules for the characteristic molar core volume. The most favourable mixing rule was found to be one based on a mole-fraction-weighted sum of the pure component molar core volumes raised to a power γ which was treated as an adjustable parameter. In this case, deviations of the experimental viscosities from the model were within ±25 %.

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“…Es handelte sich um die verbesserte Bestimmung der Sommerfeld-Feinstrukturkonstante a aus der Messung des anomalen magnetischen Moments des Elektrons in einer Penning-Falle [4,5], der Planck-Konstante h aus dem genauen Vergleich mechanischer und elektrischer Leistung mittels eines Watt-Waagen-Experiments [6] sowie der Ermittlung der universellen Gaskonstante R aus der verbesserten Messung der Schallgeschwindigkeit in Argon [7]. Eine in [3] ssenschafts-und rt s c. h af t ss t a n d o rt Be r I i n -Ad I e rs h of STA O r g a n i s a t i o n : …”

Section: Inp Und Ifw Bleiben Auf Blauer Listeunclassified

Wissenschaftsrat: Empfehlungen zu Master‐ und Bachelorstudiengängen/Kurzgefasst…/INP und IFW bleiben auf Blauer Liste/Lorbeeren der Vergangenheit: Im Maschinenbau ist Deutschland konkurrenzfähig, bei den Spitzentechnologien fällt es zurück/ITER‐FEAT: Ein Meisterstück?/Clintons Forschungsinitiative/YBCO‐Patent für Bell Labs/US‐Industrie forscht mehr/First light für XMM‐Newton/Kritik an Teststoppvotum/Yale verbessert Infrastruktur/Frankreich: Haushaltsgesetz 2000: Wo steht die Physik?/„Optics Valley”︁

et al. 2000

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Measurement of the universal gas-constant R using a spherical acoustic resonator

Cited by 242 publications

References 58 publications

Determination of the Boltzmann constant using a quasi-spherical acoustic resonator

Determination of the Boltzmann constant using a quasi-spherical acoustic resonator

Viscosities and Densities of Binary Mixtures of Hexadecane with Dissolved Methane or Carbon Dioxide at Temperatures from (298 to 473) K and at Pressures up to 120 MPa

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