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Search Publications by: Keith A Gillis (Fed)

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Displaying 1 - 25 of 45

Dynamic Measurement of Gas Flow using Acoustic Resonance Tracking

March 21, 2023
Jodie Gail Pope, Keith A. Gillis, James W. Schmidt
We measured gas flows exiting large, un-thermostated, gas-filled, pressure vessels by tracking the time-dependent pressure P(t) and resonance frequency fN(t) of an acoustic mode N of the gas remaining in each vessel. This is a proof-of-principle


June 15, 2021
Jodie Gail Pope, Aaron Johnson, James Filla, Vern E. Bean, Michael R. Moldover, Joey Boyd, Christopher J. Crowley, Iosif Isaakovich Shinder, Keith A. Gillis, John D. Wright
We describe the 15 kg/s water flow calibration standard operated by the Fluid Metrology Group of the National Institute of Standards and Technology (NIST) to calibrate liquid flow meters for customers. The 15 kg/s standard is a dynamic, gravimetric, liquid

Modeling Temperature Effects on a Coriolis Mass Flowmeter

September 2, 2020
Fabio O. Costa, Jodie Gail Pope, Keith A. Gillis
Coriolis mass flowmeters are known to be stable, have low uncertainty (± 0.1 %), and are insensitive to fluid properties. This meter type is used for many applications, including as transfer standards for proficiency testing and liquified natural gas (LNG)

Progress Towards a Gas-Flow Standard using Microwave and Acoustic Resonances

July 15, 2019
Jodie Gail Pope, Keith A. Gillis, Michael R. Moldover, Eric Harman, James Mehl
We describe our progress in the development of a novel gas flow standard using the acoustic and microwave resonances of a 1.85 m3, nearly-spherical, steel vessel at pressures up to 7 MPa. For flow calibrations using pressure and acoustic frequency

Calibration of Dynamic Pressure in a Tubing System and Optimized Design of Tube Configuration: A Numerical and Experimental Study

June 12, 2018
Matthew Kovaerk, Luke Amatucci, Keith A. Gillis, Florian Potra, James Ratino, Marc L. Levitan, DongHun Yeo
Accurate prediction of aerodynamic pressures on a building is a key factor in the estimation of wind loads on the building. Since the analytical approach has limited capacity in providing pressure estimates, wind tunnel testing is widely used. The

Characterizing Gas-Collection Volumes with Acoustic and Microwave Resonances

March 27, 2018
Jodie Gail Pope, Keith A. Gillis, Michael R. Moldover, J B. Mehl, Eric Harman
We characterized a 1.8 m3, nearly-spherical, steel shell at pressures up to 7 MPa for use as a gas flow standard. For pressure, volume, temperature, and time measurements, the shell's cavity will collect gas; for blow-down measurements, the shell will be a

NIST Programs to Advance Accurate, Internationally-Recognized Stack Emissions Measurements

September 15, 2016
Aaron Johnson, Iosif Isaakovich Shinder, Rodney A. Bryant, JohnPaul R. Abbott, Keith A. Gillis, Joey Boyd, James Filla, Michael R. Moldover
Accurate flow measurements are essential to quantify the amount of greenhouse gases (GHGs) and other pollutants emitted from power plant stacks. Although protocols have been developed, the uncertainty of stack flow measurements has not been documented. 

Detecting leaks in gas-filled pressure vessels using acoustic resonances

May 6, 2016
Keith A. Gillis, Michael R. Moldover, James B. Mehl
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 resonance

Measurement Challenges and Metrology for Monitoring CO2 Emissions from Smokestacks – Workshop Summary

January 20, 2016
Aaron N. Johnson, Rodney A. Bryant, Tamae M. Wong, James R. Whetstone, Eric Harman, Woong Kang, Keith A. Gillis, Hsin-Hung Lee, Iosif I. Shinder, Liang Zhang
On April 20-21, 2015, NIST hosted a workshop that, through measurement science, enabled the owners of stationary sources (primarily the electric power industry) and their regulatory agencies (federal and state) to better characterize greenhouse gas (GHG)

Test of a virtual cylindrical acoustic resonator for determining the Boltzmann constant

August 19, 2015
XiaoJuan Feng, Hong Lin, Keith A. Gillis, Michael R. Moldover, Jintao Zhang
We report progress in determining the Boltzmann constant k B using a virtual acoustic resonator derived by combining the measured frequencies of the longitudinal acoustic modes of two argon-filled, cylindrical, cavity resonators in such a way as to

Measuring collected gas with microwave and acoustic resonances

April 23, 2015
Keith A. Gillis, James W. Schmidt, Michael R. Moldover, James B. Mehl
With calibrations of large flow meters in mind, we established the feasibility of determining the mass M of argon gas contained within a 0.3 m 3 commercially manufactured pressure vessel ("tank") with a relative standard uncertainty of u r(M) = 0.0016 at 0

"Weighing" a Gas With Microwave and Acoustic Resonances

March 24, 2015
Keith A. Gillis, James B. Mehl, James W. Schmidt, Michael R. Moldover
With calibrations of large flow meters in mind, we established the feasibility of determining the mass Mof argon gas contained within a 0.3 m 3 commercially manufactured pressure vessel ("tank") with a relative uncertainty of u r(M) = 0.0015 at 0.6 MPa by

Microwave Determination of the Volume of a Pressure Vessel

December 9, 2014
Michael R. Moldover, James W. Schmidt, Keith A. Gillis, James B. Mehl, John D. Wright
Using microwave techniques that are scalable to very large volumes, we measured the interior volume of a 0.3 m 3, commercially-manufactured, pressure vessel with an uncertainty of 0.05 %, as confirmed by independent, more-accurate, gas-expansion

Acoustic Techniques for Measuring Transport Properties of Gases

May 22, 2014
Keith A. Gillis, Michael R. Moldover
We describe the principles, techniques, and performance of acoustic resonators used to measure the shear viscosity, the thermal conductivity, and the bulk viscosity in gases. We developed the Greenspan acoustic viscometer at NIST, where colleagues used it

Direct measurements of mass-specific optical cross sections of single component aerosol mixtures

July 22, 2013
James Radney, Xiaofei Ma, Keith A. Gillis, Michael R. Zachariah, Joseph T. Hodges, Christopher D. Zangmeister
The optical properties of atmospheric aerosols vary widely, being dependent upon particle composition, morphology and mixing state. This diversity and complexity of aerosols motivates measurement techniques that can discriminate and quantify a variety of

Microwave measurements for gas thermometry up to the copper point

May 13, 2013
XiaoJuan Feng, Keith A. Gillis, Michael R. Moldover, James B. Mehl
We measured 5 microwave resonance frequencies f N of an argon-filled cylindrical cavity at temperatures up to 1349 K. The repeatability of both the measured frequencies u(f N) and the scaled half-widths u(g N)/ f N was better than 10 -6f N. The measurement

Room Temperature Acoustic Transducers for High-Temperature Thermometry

July 9, 2012
Dean C. Ripple, William E. Murdock, Gregory F. Strouse, Keith A. Gillis, Michael R. Moldover
We have successfully conducted highly-accurate, primary acoustic thermometry at 600 K using a sound source and a sound detector at room temperature. We describe the source, the detector, and the ducts that connected them to our cavity resonator. This


June 22, 2012
Lee J. Gorny, Keith A. Gillis, Michael R. Moldover
As a part of NIST’s program to standardize measurements of greenhouse gas emissions, we are developing a long-wavelength acoustic flowmeter (LWAF) for accurate, economical measurements of exhaust flows from coal-burning power plants. Measurements of the