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Metrology

Flow metrology & rheology

News and Updates

schematic of sound-wave transmitter and receiver

Sounding Out a New Way to Measure Gas Flow

Researchers at NIST have developed a new — and sound — way to accurately measure the rate at which gas flows in and out of a vessel. The technique, which uses

Projects and Programs

shaded quasi sphere

Atomic Standard for Pressure

Ongoing
Atomic physicists have calculated the pressure p( n, T) of helium gas as a function of the gas's temperature T and its refractive index at microwave frequencies, n. Near room temperature and 4 MPa, the fractional uncertainties from the calculations, the impurities in helium, state-of-art
The NIST Acoustic Thermometer

Acoustic Techniques in Fluid Metrology

Ongoing
In collaboration with NIST's Chemical Sciences Division, we use photoacoustic resonators for continuous monitoring of the CO2 concentration in ambient air from a tall building rooftop; (see Fig. 2) [ 1] for measuring the optical properties of particles (e.g. soot) in air that affect the energy

The NIST Chemistry Webbook

Ongoing
Intended Impact It is part of NIST's mission to distribute Standard Reference Data to scientists, engineers, educators, and the general public. The NIST Chemistry WebBook is intended to help fulfill NIST's mission by distributing such data over the Internet. Objective Develop a web site

Material Qualification

Ongoing
Objective To develop, utilize, and analyze methods of characterizing the precursor materials in additive manufacturing in both virgin and recycled states with the goal of advancing measurement science to benefit the AM community. The components of principal interest will include the rheological

Publications

Tools and Instruments

transient gas flow instruments

Transient Gas Flow Facility

A compressor is used to pressurize up to twenty-five 40 L gas cylinders to 35 MPa. The cylinders can then be used as a source of rapidly changing gas flow by
gas flow standards instrument

Gas Flow Standards

NIST uses pressure, volume, temperature, and time ( PVTt) standards to calibrate gas flow meters. PVTt flow standards generate selected, steady gas flows
wind tunnel instrument

Wind Tunnel

NIST’s wind tunnel can produce air speeds between 0.15 m/s and 40 m/s. The air speed reference is a Laser Doppler Anemometer (LDA) with an uncertainty of 2.5 %

Awards