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Metrology

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Displaying 876 - 900 of 2729

NIST's Fully Dynamic Gravimetric Liquid Flowmeter Standard.

April 13, 2015
Author(s)
Jodie G. Pope, Aaron N. Johnson, Bernard J. Filla, Joey T. Boyd, Vern E. Bean, Christopher J. Crowley
We describe a new dynamic, gravimetric, liquid flow standard (LFS) that determines flow by measuring the rate of change of the liquid mass accumulating in a collection tank. The LFS is a fully- automated,15 kg/s system that uses a proportional–integral

Traceability for Microwave Power Measurements: Past, Present, and Future

April 13, 2015
Author(s)
Ronald A. Ginley
The need for traceable microwave power measurements for use in communications, defense, spectral line investigation, molecular particle signature identification, material property characterization and others is well established. Traceability for power

Building a Spring-Transport Mechanism for Spinning Rotor Gauges

April 3, 2015
Author(s)
James A. Fedchak, Julia K. Scherschligt, Makfir Sefa, Nick Phandinh
Spinning rotor gauges (SRGs) are widely used as transfer standards in inter-laboratory comparisons and as secondary standards by calibration laboratories. In both of these applications, it is necessary to ship the SRG for calibration, often internationally

Cavity ring-down spectrometer for high-fidelity molecular absorption measurements

April 1, 2015
Author(s)
Vincent T. Sironneau, Hong Lin, Zachary Reed, Joseph T. Hodges
We present a cavity ring-down spectrometer which was developed for near-infrared measurements of laser absorption by atmospheric greenhouse gases. This system has several important attributes that make it possible to conduct broad spectral surveys and to

NGD Cold Neutron Prompt Gamma-ray Activation Analysis Spectrometer at NIST

April 1, 2015
Author(s)
Rick L. Paul, Dagistan NMN Sahin, Jeremy C. Cook, Christoph W. Brocker, Richard M. Lindstrom, Donna J. O'Kelly
A new instrument for cold neutron prompt gamma-ray activation analysis (CNPGAA) has been designed and constructed as part of the recent expansion of the cold neutron guide hall at the NIST Center for Neutron Research (NCNR). Located on neutron guide NGD

First measurements of the flux integral with the new NIST-4 watt balance

March 31, 2015
Author(s)
Darine El Haddad, Frank Seifert, Leon Chao, Yusi A. Cao, Georgio A. Sineriz, Jon R. Pratt, David B. Newell, Stephan Schlamminger
In early 2014, construction of a new watt balance, named NIST-4, has started at the National Institute of Standards and Technology (NIST). In a watt balance, similar to a mass comparator, the gravitational force of an unknown mass is compensated by an

Draining Test Measures and Provers

March 26, 2015
Author(s)
Gloria D. Lee
This article reviews the correct procedures for draining 5-gallon test measures and truck mounted provers, frequently asked questions concerning the test procedures for draining test measures and provers, and provides information on additional training

"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

Local Strain Exerted on Nb 3 Sn Filaments in an ITER Strand

March 13, 2015
Author(s)
Kozo Osamura, Shutaro Machiya, Stefanus Harjo, Tatsushi Nakamoto, Najib Cheggour, Arend Nijhuis
As part of an international project to benchmark facilities for measuring the strain dependence of critical current in ITER Nb 3Sn strands, direct measurement of local strain exerted on Nb 3Sn filaments was attempted at cryogenic temperature by means of

Considerations for Design and In-Situ Calibration of High Accuracy Length Artifacts for Field Testing of Laser Trackers

March 1, 2015
Author(s)
Aaron Hudlemeyer, Daniel S. Sawyer, Christopher J. Blackburn, Vincent Lee, Mark Meuret, Craig M. Shakarji
Interim testing of laser trackers can be problematic due to the lack of high precision, long length artifacts that maintain their calibrated lengths during measurement. Gravitational loading, fixturing forces, and changes in the atmospheric conditions can

Measurement of the 240Pu/239Pu Mass Ratio Using a Transition-Edge-Sensor Microcalorimeter for Total Decay Energy Spectroscopy

February 27, 2015
Author(s)
Daniel R. Schmidt, Douglas A. Bennett, James P. Hays-Wehle, Daniel S. Swetz, Joel N. Ullom, Andrew Hoover, Mark Croce, Michael W. Rabin, Evelyn Bond, Terry Holesinger, Gerd Kunde, Laura Wolfsbereg
We have developed a new category of sensor for measurement of the 240Pu/239Pu mass ratio from aqueous solution samples with advantages over existing methods. Aqueous solution plutonium samples were evaporated and encapsulated inside of a gold foil absorber

The Office of Weights and Measures Proposes Revisions to the Method of Sale for Animal Bedding and Recommends New Test Procedures and Test Measures for Use in Verifying the Quantity Declarations on Packages of Peat Moss and Animal Bedding

February 19, 2015
Author(s)
Kenneth S. Butcher
Animal Bedding (bedding), also called pet or stall bedding, litter or simply bedding, is generally sold by dry volume in compressed or uncompressed packages. Based on numerous failed inspections of packaged animal bedding, the Office of Weights and

A summary of the Planck constant measurements using a watt balance with a superconducting solenoid at NIST

February 5, 2015
Author(s)
Stephan Schlamminger, Richard L. Steiner, Darine El Haddad, David B. Newell, Frank C. Seifert, Leon S. Chao, Ruimin Liu, Edwin R. Williams
Researchers at the National Institute of Standards and Technology have been using a watt balance, NIST-3, to measure the Planck constant h for over ten years. Two recently published values disagree by more than one standard deviation. The motivation for
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