The National Institute of Standards and Technology (NIST) has performed calibrations of gas flowmeters using piston and bell provers for three decades. Most of the meters calibrated have been either critical flow nozzles or laminar flowmeters since these meter types are generally chosen as the working standards or transfer standards by other flow calibration laboratories. Often the same meters ...

Maintaining traceability for transfer standards in the range of 10 Pa to 5 kPa is critical to many calibration laboratories. However, standards with suitable uncertainty that can also be practically implemented in the typical laboratory have not been available. A new pressure standard based on piston-cylinder technology has been developed that provides the measurement uncertainty needed to supp...

PURPOSE To report intra- and interinstrument calibration methods for corneal backscatter analysis by in vivo confocal microscopy. METHODS Applicability of two reference standards was evaluated for corneal backscatter calibration. Repeated measurements of four concentrations of AMCO Clear (GFS Chemicals, Inc., Powell, OH) suspension and three transparencies (26%, 49%, and 65%) of polymethylmet...

Several standards for radiometric calibration were measured repeatedly with a spectroradiometer in order to understand how they compared in accuracy and stability. The tested radiance standards included a NIST 1000 W bulb and Spectralon panel, two calibrated and stabilized integrating spheres, and a cavity blackbody. Results indicate good agreement between the blackbody and 1000 W bulb/Spectral...

This paper describes a constant impedance transmission line pulse system with new measurement capabilities and improved accuracy. The paper enforces a broader look at transmission line pulse (TLP) data, beyond the – curves. Accurate TLP measurements and actual TLP/HBM device data are used to demonstrate effects and HBM/TLP correlation and miscorrelation. Finally, a calibration method and standa...