Primary pressure standard based on piston-cylinder assemblies. Calculation of effective cross sectional area based on rarefied gas dynamics

Sharipov, Felix; Yang, Yuanchao; Ricker, Jacob E.; Hendricks, James

doi:10.1088/0026-1394/53/5/1177

Cited by 21 publications

(15 citation statements)

References 29 publications

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“…The pressure difference between the heights of +2.5 mm and -2.5 mm is 0.75 Pa. According to the calculation of Sharipov et al [27], this difference arises from additional forces on the piston due to the gas flow in the crevice between piston and sleeve. Moreover, the gas pressure beneath the piston and filling the crevices causes an elastic deformation of both sleeve and piston.…”

Section: Experimental Results and Discussion 31 Comparisons Betweenmentioning

confidence: 97%

Realization of ppm level pressure stability for primary thermometry using a primary piston gauge

et al. 2020

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To achieve an uncertainty of 0.25 mK in single-pressure refractive-index gas thermometry (SPRIGT), the relative pressure variation of He-4 gas in the range 30 kPa to 90 kPa, should not exceed 4 ppm (k=1). To this end, a novel pressure control system has been developed. It consists of two main parts: a piston gauge to control the pressure, and a home-made gas compensation system to supplement the micro-leak of the piston gauge. In addition, to maintain the piston at constant height, a servo loop is used that automatically determines in real time the amount of extra gas required. At room temperature, the standard deviations of the stabilized pressure are 3.0 mPa at 30 kPa, 4.5 mPa at 60 kPa and 2 mPa at 90 kPa. For the temperature region 5 K-25 K used for SPRIGT in the present work, the relative pressure stability is better than 0.16 ppm i.e. 25 times better than required. Moreover, the same pressure stabilization system is readily transposable to other primary gas thermometers.

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Section: Experimental Results and Discussion 31 Comparisons Betweenmentioning

confidence: 97%

Realization of ppm level pressure stability for primary thermometry using a primary piston gauge

et al. 2020

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“…At ambient temperature and for frequencies up to 100 MHz, the denominator is equivalent to hν/kT to better than 10 −9 , so the equation simplifies to the well-known Johnson-Nyquist formula [34,35] given by equipartition:…”

Section: Johnson Noise Thermometrymentioning

confidence: 99%

Determinations of the Boltzmann Constant

Pitre

2018

2018 Conference on Precision Electromagnetic Measurements (CPEM 2018)

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Constante de Boltzmann Thermométrie primaire Système international d'unités We review measurements of the Boltzmann constant, k, the value of which is soon to be fixed at exactly 1.380 649 × 10 −23 J•K −1 for the future revised Système international of units. In addition to a description of the theoretical background and of diverse experimental techniques (acoustic thermometry, Johnson noise thermometry, dielectric constant gas thermometry, and Doppler broadened molecular spectroscopy), the article highlights the decisive role of ab initio calculations of the thermophysical properties of gases, especially helium-4. Perspectives for improvements in thermometry are outlined in the wake of the new definition.

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“…To calculate the effective area, the theory of rarefaction gas dynamics has been used. A formula was derived for calculating the effective area, which is a combined form of viscous and free-molecular flow of gas in a medium [5][6][7][8]. The NIST USA, and PTB Germany have discarded the Dadson formula to calculate the effective area of p-c assembly and opted to use the rarefaction gas dynamics method.…”

Section: Introductionmentioning

confidence: 99%

Establishment of air piston gauge as primary pressure standard at CSIR-National Physical Laboratory INDIA

2020

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The air piston gauge (APG) was established at CSIR-National Physical Laboratory, India (NPLI) since 2000. Later the same piston- cylinder(p-c) assembly was calibrated in NIST USA; however, it was never published for metrology communities. As per international protocol, the establishment of the APG as a primary standard, the effective area of p-c assembly, and masses must be directly traceable to SI units. The first time we have calculated the effective area and associated uncertainty of p-c assembly using dimension and mass metrology, traceability to the SI units, i.e., meter and kilogram. To realize the APG as primary pressure standards, we have calculated the effective area of p-c assembly of APG directly from dimension metrology, which is further supported by various other methods. The effective area values obtained in the pressure range of 6.5 – 360 kPa lie in the range of 3.356729 – 3.357248 cm² due to uncertainty limitation in the measurement of dimension of internal diameter of cylinder. The expected values of the effective area which are also measured from cross-float technique against ultrasonic interferometer manometer (UIM), primary pressure standards. The accuracy in effective area measurement is possible only when the resolution in the internal radius of the cylinder should at least be up to 5th decimal order and the uncertainty is 80 nm. The expanded uncertainty was measured nearly 11 ppm at <em>k</em> = 2 by considering the uncertainty in internal radii of cylinder and radii of piston around 80 nm.

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Primary pressure standard based on piston-cylinder assemblies. Calculation of effective cross sectional area based on rarefied gas dynamics

Cited by 21 publications

References 29 publications

Realization of ppm level pressure stability for primary thermometry using a primary piston gauge

Realization of ppm level pressure stability for primary thermometry using a primary piston gauge

Determinations of the Boltzmann Constant

Establishment of air piston gauge as primary pressure standard at CSIR-National Physical Laboratory INDIA

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