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Topic Area: Gas Metrology
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1. Long-term stability of metal-envelope enclosed ionization gauges
Topic: Gas Metrology
Published: 12/1/2012
Authors: James A Fedchak, Dana R Defibaugh
Abstract: Ionization vacuum gauges are used as secondary standards by calibration laboratories and as transfer standards in intercomparisons among metrology laboratories. A quantitative measurement of gauge stability with respect to the gauge calibration fact ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=911249

2. Second-order boundary corrections to the radial acoustic eigenvalues for a spherical cavity
Topic: Gas Metrology
Published: 8/17/2012
Author: Keith A Gillis
Abstract: We calculated the eigenvalues of the radially-symmetric acoustic modes of a gas-filled, spherical cavity to order ({delta}^dT^/{I}a{/I})^u2^, where {delta}^dT^ is the thickness of the thermal boundary layer and {I}a{/I} is the radius of the cavity. O ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=911620

3. Frequency-stabilized cavity ring-down spectroscopy measurements of carbon dioxide isotope ratios
Topic: Gas Metrology
Published: 5/15/2011
Authors: Joseph Terence Hodges, David A Long, Mitchio Okumura, Charles E Miller
Abstract: Carbon dioxide (CO2) isotopic ratios were measured at 1.6 μm through the use of frequency-stabilized cavity ring-down spectroscopy (FS-CRDS). We report the highest spectrum signal-to-noise ratios to date for CO2 transitions, with values as high ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=907103

4. Stability Assessment of Gas Mixtures Containing Terpenes at Nominal 5 nmol/mol Contained in Treated Aluminum Gas Cylinders
Topic: Gas Metrology
Published: 8/9/2010
Author: George C Rhoderick
Abstract: Studies of climate change increasingly recognize the diverse influences exerted by terpenes (Tp) in the atmosphere, including roles in particulates, ozone formation & their oxidizing potential. Measurements of key Tp suggest atmospheric concentration ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=905302

5. Standard Photoacoustic Spectrometer: Model and Validation using O2 A-Band Spectra
Topic: Gas Metrology
Published: 6/30/2010
Authors: Keith A Gillis, Daniel K. Havey, Joseph Terence Hodges
Abstract: We model and measure the absolute response of an intensity-modulated photoacoustic spectrometer comprising a 10 cm long resonator and having a {I}Q{/I}-factor of approximately 30. We present a detailed theoretical analysis of the system and predict ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=904841

6. Optimizing Acoustic Measurements of the Boltzmann Constant
Topic: Gas Metrology
Published: 11/22/2009
Author: Michael R Moldover
Abstract: We review the progress in acoustic metrology of gases that has occurred since the 1988 measurement of the universal gas constant {I}R{/I} using a spherical acoustic resonator. The advances in understanding resonators and in calculating the thermophys ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=902117

7. Comparison of Five Natural Gas Equations of State Used for Flow and Energy Measurement
Topic: Gas Metrology
Published: 8/14/2009
Authors: Aaron N Johnson, William Johansen
Abstract: Measurements of the flow and the energy content of natural gas rely on equations of state to compute four thermodynamic properties: 1) compressibility factor; 2) critical flow factor; 3) speed of sound; and 4)isentropic exponent. We compare these com ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=903432

8. The Calculation of Natural Gas Viscosity
Topic: Gas Metrology
Published: 8/14/2009
Authors: Aaron N Johnson, William Johansen
Abstract: The calculation of natural gas viscosity has been implemented many different ways including the use of constants. Different methods of calculating natural gas viscosity may produce values with differences as large as 50%. Increasing natural gas price ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=903462

9. Reference measurements of Hydrogen's Dielectric Permittivity
Topic: Gas Metrology
Published: 8/10/2009
Authors: James W Schmidt, Michael R Moldover, Eric May
Abstract: We used a quasi-spherical cavity resonator to measure the relative dielectric permittivity {epsilon}^dr^ of H^d2^ at frequencies from 2.4 GHz to 7.3 GHz, at pressures up to 6.5 MPa, and at the temperatures 273 K and 293 K. The resonator was calibrat ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=901652

10. High Definition Flow
Topic: Gas Metrology
Published: 8/1/2009
Authors: John D Wright, Michael R Moldover
Abstract: From pharmaceutical production to the natural gas market, exact flow measurements are critical. Here's how NIST helps keep us all on the same page.
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=832391