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Metrology

Flow metrology & rheology

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Displaying 76 - 100 of 177

"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

Dynamic Gravitational Standard for Liquid Flow: Model and Measurements

August 14, 2009
Author(s)
Iosif I. Shinder, Michael R. Moldover
We report progress in testing a dynamic gravimetric standard using both steady and unsteady water flows. For steady flows in the range 10 kg/s to 60 kg/s, the difference between the dynamic standard and NIST s static primary standard was 0.015 % with a

The Calculation of Natural Gas Viscosity

August 14, 2009
Author(s)
Aaron N. Johnson, William Johansen
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 prices

High Definition Flow

August 1, 2009
Author(s)
John D. Wright, Michael R. Moldover
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.
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