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Search Publications by: John D. Wright (Assoc)

Displaying 26 - 50 of 134

Microparticle tracking velocimetry as a tool for microfluidic flow measurements

June 7, 2017

Author(s)

Paul NMN Salipante, Steven D Hudson, James W. Schmidt, John D. Wright

The accurate measurement of flows in microfluidic channels is important for commercial and research applications. We compare the accuracy of flow measurement techniques over a wide range flows. Flow measurements made using holographic microparticle

Transfer Standard Uncertainty Can Cause Inconclusive Inter-Laboratory Comparisons

October 7, 2016

Author(s)

John D. Wright, Blaza Toman, Bodo Mickan, Gerd Wubbeler, Olha Bodnar, Clemens Elster

Inter-laboratory comparisons use the best available transfer standards to check the participants uncertainty analyses, identify underestimated uncertainty claims or unknown measurement biases, and improve the global measurement system. For some measurands

Back Pressure Ratio and the Transonic Resonance Mechanism of Low Unchoking in Critical Flow Venturis

September 28, 2016

Author(s)

John D. Wright, Keith A. Gillis, Aaron Johnson, Ida I. Shinder

Reliable Critical Flow Venturi (CFV) operation requires sonic velocity at the throat of the device. The maximum ratio of exit pressure to inlet pressure that ensures this sonic velocity is referred to as the maximum back pressure ratio (MBPR). Being able

Extended Data Analysis of Bilateral Comparisons with Air and Natural Gas up to 5 MPa

September 28, 2016

Author(s)

John D. Wright, Bodo Mickan, J-P Vallet, CHUNHUI LI

In 2015, the PTB, LNE-LADG, NIM and NIST performed informal bilateral comparisons using six critical venturi nozzles. The goal of the comparisons was to prove the equivalence of reference standards for gas flow using pressurized air and natural gas at

ASME MFC-72016: Measurement of Gas Flow by Means of Critical Flow Venturis and Critical Flow Nozzles

September 1, 2016

Author(s)

John D. Wright, Aaron N. Johnson

This Standard applies only to the steady flow of single-phase gases through critical flow venturis, CFVs, of shapes specified herein (also sometimes referred to as critical flow nozzles or critical flow venturi nozzles). This document applies to critical

Hydrogen Field Test Standard: Laboratory and Field Performance

November 10, 2015

Author(s)

Jodie G. Pope, John D. Wright

The National Institute of Standards and Technology (NIST) developed a prototype field test standard (FTS) that incorporates three test methods that could be used by state weights and measures inspectors to periodically test retail hydrogen dispensers, much

Micro-Flow Calibration Facility at NIST

April 15, 2015

Author(s)

James W. Schmidt, John D. Wright

The Fluid Metrology Group (FMG) at NIST is developing a primary, dynamic gravimetric liquid flow standard for use in the range 1 mL/min to 100 nL/min (and eventually lower). An elevated reservoir of water with a pressure head of a few centimeters provides

Pass / Fail / Inconclusive Criteria for Inter-Laboratory Comparisons

April 14, 2015

Author(s)

Blaza Toman, Bodo Mickan, Gerd Wubbeler, Olha Bodnar, Clemens Elster, John D. Wright

Inter-laboratory comparisons use the best available transfer standards to check participants uncertainty analyses, identify underestimated uncertainty claims or measurement errors, and improve the global measurement system. For some measurands (e.g. flow)

The Effect of Liquid Kinematic Viscosity and Drain Time on the Volume Delivered from a Test Measure

April 14, 2015

Author(s)

John D. Wright, Sherry D. Sheckels, Lachance Christian, Farhad Sharifi, Dominic Ondoro

Volume test measures are used for calibration and traceability of petroleum measurements and their low uncertainty is important for the equitable trade of valuable liquids. The volume delivered from a test measure depends in part on the volume of liquid

Thermal Effects on Critical Flow Venturis

April 14, 2015

Author(s)

John D. Wright, Aaron N. Johnson, Michael R. Moldover, Woong Kang, Liang Zhang

Critical flow venturis (CFVs) are widely used as working and transfer standards for gas flow measurement because of their long-term calibration stability (5 (e.g., a 2 mm throat diameter flowing air at 1 MPa), CFVs exhibit sensitivity to the environmental

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

A Comparison of Primary Gas Flow Standards Spanning the Range 10 sccm N2 to 10 slm N2

July 27, 2014

Author(s)

John D. Wright, Casey Rombouts, Bair Michael, Jean Barbe, Rainer Kramer, Zdenek Krajicek

We describe an international comparison of gas flow standards spanning the range 2.1 x 10-4 g/s (10 sccm) of nitrogen to 0.21 g/s (10 slm) of nitrogen. For all the participating laboratories, |En|

Hydrogen Field Test Standard: Laboratory Performance

April 14, 2014

Author(s)

Jodie G. Pope, John D. Wright

NIST developed a prototype field test standard (FTS) that incorporates three test methods that could be used by state weights and measures inspectors to periodically test retail hydrogen dispensers, much as gasoline dispensers are tested today. The three