Zobrazeno 1 - 10
of 84
pro vyhledávání: '"James B. Mehl"'
Autor:
James B. Mehl, J. T. Zhang, K Zhang, Y. N. Duan, XiaoJuan Feng, Lin Hong, Keith A. Gillis, Michael R. Moldover
Publikováno v:
Metrologia. 54(5)
We report a new determination of the Boltzmann constant kB using a cylindrical acoustic gas thermometer. We determined the length of the copper cavity from measurements of its microwave resonance frequencies. This contrasts with our previous work (Zh
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d3ec36a7b586042db7cd132141225ffa
https://pubmed.ncbi.nlm.nih.gov/29332954
https://pubmed.ncbi.nlm.nih.gov/29332954
Autor:
James B Mehl
Publikováno v:
Metrologia. 52:S227-S232
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::e02da103b6e8bf0deea3ddfc42b7c5ea
https://doi.org/10.1088/0026-1394/52/5/s227
https://doi.org/10.1088/0026-1394/52/5/s227
Autor:
James B. Mehl, P. A. Giuliano Albo, Marc Himbert, B. Marty, A. Allard, Bo Gao, Cécile Guianvarc'H, F. Sparasci, Laurent Pitre, M.D. Plimmer, C Martin, Lara Risegari, Michael R. Moldover
Publikováno v:
Metrologia
Metrologia, IOP Publishing, 2017, 54 (6), pp.856-873. ⟨10.1088/1681-7575/aa7bf5⟩
Metrologia (0026-1394) (Iop Publishing Ltd), 2017-12, Vol. 54, N. 6, P. 856-873
Metrologia, IOP Publishing, 2017, 54 (6), pp.856-873. ⟨10.1088/1681-7575/aa7bf5⟩
Metrologia (0026-1394) (Iop Publishing Ltd), 2017-12, Vol. 54, N. 6, P. 856-873
The SI unit of temperature will soon be redefined in terms of a fixed value of the Boltzmann constant k derived from an ensemble of measurements worldwide. We report on a new determination of k using acoustic thermometry of helium-4 gas in a 3-litre
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::9c4b74122237361b44d7ade83c7f7aa3
https://hal.archives-ouvertes.fr/hal-02138281
https://hal.archives-ouvertes.fr/hal-02138281
Publikováno v:
Flow Measurement and Instrumentation. 69:101592
We describe our progress in developing a novel gas flow standard that utilizes 1) microwave resonances to measure the volume, and 2) acoustic resonances to measure the average gas density of a collection tank/pressure vessel. The collection tank is a
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::0a89062aae4f563544abe6d4501149fb
https://doi.org/10.1016/j.flowmeasinst.2019.101592
https://doi.org/10.1016/j.flowmeasinst.2019.101592
Publikováno v:
Metrologia. 50:219-226
This work explores the feasibility of acoustic gas thermometry (AGT) in the range 700 K to the copper point (1358 K) in order to more accurately measure the differences between ITS-90 and the thermodynamic temperature. To test material suitability an
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::1dff99a4a1f0a462aa18ed4ead1b7685
https://doi.org/10.1088/0026-1394/50/3/219
https://doi.org/10.1088/0026-1394/50/3/219
Publikováno v:
The Review of scientific instruments. 87(5)
We demonstrate that a leak from a large, unthermostatted pressure vessel into ambient air can be detected an order of magnitude more effectively by measuring the time dependence of the ratio p/f(2) than by measuring the ratio p/T. Here f is the reson
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::2c9b62a9e5c8b6ddcb71766ba649b96b
https://pubmed.ncbi.nlm.nih.gov/27250456
https://pubmed.ncbi.nlm.nih.gov/27250456
Autor:
James B. Mehl, Roberto Gavioso, Eric F. May, Daniel Truong, P. A. Giuliano Albo, D R Flack, Giuliana Benedetto, Laurent Pitre, M de Podesta
Publikováno v:
Metrologia. 47:588-604
Acoustic thermometry using a gas-filled quasi-spherical resonator (QSR) is one of the most promising techniques for measuring the Boltzmann constant kB with low uncertainty. Dimensional metrology with coordinate measurement machines (CMMs) can be use
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::8d4c6188948165fc39c102188b7756cb
https://doi.org/10.1088/0026-1394/47/5/010
https://doi.org/10.1088/0026-1394/47/5/010
Autor:
James B. Mehl
Publikováno v:
International Journal of Thermophysics. 31:1259-1272
Quasispherical resonators are cavity resonators whose acoustic and electromagnetic modes are used in precision measurements, with shapes designed to split the l = 1 triplet modes to facilitate precise determination of the eigenfrequencies. The shapes
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::2a5a88acb9a08e43c9401582f1136d5d
https://doi.org/10.1007/s10765-010-0731-y
https://doi.org/10.1007/s10765-010-0731-y
Publikováno v:
The Journal of the Acoustical Society of America. 143:1844-1844
We characterized a 1.8 m3, quasi-spherical resonator, a pressure vessel informally known as the “big blue ball” or “BBB.” The BBB will be the collection volume of a NIST-designed gas-flow standard that will operate at pressures up to 7 MPa. U
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::f9e7ea68ae2846b23873ecfe28997c57
https://doi.org/10.1121/1.5036054
https://doi.org/10.1121/1.5036054
Publikováno v:
International Journal of Thermophysics. 31:740-755
The spherical version of the hydrogen intermolecular potential $${\phi_{\rm P}}$$ recently determined in ab initio calculations by Patkowski et al. was used to calculate the viscosity and thermal conductivity of hydrogen using a full quantum-mechanic
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::2a744b39cf79a6ba39c1d742d9dbbf66
https://doi.org/10.1007/s10765-009-0697-9
https://doi.org/10.1007/s10765-009-0697-9