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Metrology

Flow metrology and rheology

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Displaying 76 - 100 of 184

Detecting leaks in gas-filled pressure vessels using acoustic resonances

May 6, 2016
Author(s)
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

In-Situ Metrology to Characterize Water Vapor Delivery during Atomic Layer Deposition

May 2, 2016
Author(s)
Tariq Ahmido, William A. Kimes, Brent A. Sperling, Joseph T. Hodges, James E. Maslar
Water is often employed as the oxygen source in metal oxide atomic layer deposition (ALD) processes. It has been reported that variations in the amount of water delivered during metal oxide ALD can impact the oxide film properties. Hence, one contribution

Reclamation-NIST Exploratory Research Symposium Summary Report

April 6, 2016
Author(s)
Nicholas Barbosa, Jessica Torrey
The Reclamation-NIST Exploratory Research Symposium was held on August 4-5, 2015, at the Reclamation Denver Federal Center facility in Lakewood, CO, and the NIST facility in Boulder, CO. Staff from the Bureau of Reclamation and the National Institute of

A New Experiment for Determining Evaporation and Condensation Coefficients of Cryogenic Propellants

March 1, 2016
Author(s)
Kishan Bellur, E F. Medici, M Kulshreshtha, V Konduru, D Tyrewala, A Tamilarasan, J McQuillen, Juscelino Leao, Daniel S. Hussey, David L. Jacobson, Julia Scherschligt, J Hermanson, C Choi, J Allen
Passive and active technologies have been used to control propellant boil-o , but the current state of understanding of cryogenic evaporation and condensation in microgravity is insucient for designing large cryogenic depots critical to the long-term

Measuring collected gas with microwave and acoustic resonances

April 23, 2015
Author(s)
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
Author(s)
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
Author(s)
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
Author(s)
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

Viscosity-ratio measurements with capillary viscometers

May 20, 2014
Author(s)
Robert F. Berg, Eric F. May, Michael R. Moldover
Viscosity-ratio measurements made with capillary viscometers exploit the accurate values of the viscosity of helium resulting from ab initio calculations. Accurate values of the argon-to-helium viscosity ratio are now used for primary acoustic thermometry

Viscosity-ratio measurements with capillary viscometers

November 27, 2013
Author(s)
Robert F. Berg, Eric F. May, Michael R. Moldover
Viscosity-ratio measurements made with capillary viscometers exploit the accurate values of the viscosity of helium calculated ab initio. Accurate values of the argon-to-helium viscosity ratio are now used for primary acoustic gas thermometry and for the

IMPROVEMENTS TO NIST'S AIR SPEED CALIBRATION SERVICE

September 24, 2013
Author(s)
Iosif I. Shinder, Christopher J. Crowley, Bernard J. Filla, Michael R. Moldover
We discuss five significant improvements to the Air Speed Calibration Service conducted by the National Institute of Standards and Technology (NIST): 1. Reduced-uncertainty calibrations of the secondary standard [Laser Doppler Anemometer, (LDA)] using a

The Effect of Turbulence on a Multi-Hole Pitot Calibration

June 10, 2013
Author(s)
Christopher J. Crowley, Iosif I. Shinder, Michael R. Moldover
Abstract- Accurate calibrations of multi-hole Pitot tubes require thousands of measurements spanning ranges of the fluid’s velocity, and the pitch and yaw angles. When calibrating a commercially-manufactured multi-hole Pitot tube in NIST’s low-turbulence

ThermoData Engine (TDE): Software Implementation of the Dynamic Data Evaluation Concept. 8. Properties of Material Streams and Solvent Design

December 3, 2012
Author(s)
Vladimir Diky, Robert D. Chirico, Chris D. Muzny, Andrei F. Kazakov, Kenneth G. Kroenlein, Joe W. Magee, Ilmutdin M. Abdulagatov, Carlos A. Diaz-Tovar, Jeong W. Kang, Rafiqul Gani, Michael D. Frenkel
ThermoData Engine (TDE) is the first full-scale software implementation of the dynamic data evaluation concept, as reported in this journal. The present paper describes the first application of this concept to the evaluation of thermophysical properties for

Bilateral Comparison Confirms NIMs and NISTs Gas Flow Capabilities

October 15, 2010
Author(s)
Aaron N. Johnson, CHUNHUI LI
The bilateral comparison between NIM and NIST for gas flow was conducted from June 2008 to October 2009. Two critical flow venturis (CFVs) with nominal throat diameters of 10 mm and 20 mm, respectively, were selected as transfer standards. The CFVs were

Properties for Accurate Gas Flow Measurements

October 15, 2010
Author(s)
John D. Wright
Accurate gas properties are needed to take full advantage of the low uncertainties provided by NIST’s Gas Flow Calibration Services. If a flowmeter user and NIST use different values for these properties (molecular mass, compressibility, density, viscosity

Feasibility of an Accurate Dynamic Standard for Water Flow

June 1, 2010
Author(s)
Iosif I. Shinder, Michael R. Moldover
We used NIST's primary water flow standard to study the feasibility of accurately determining mass flow rates m dot of water "dynamically," that is from the time derivative of the weight W of the collection tank: m dot,dynamic = (dW/dt)/g. When data for a
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