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Metrology

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Displaying 826 - 850 of 2729

PROGRESS ON MAGNETIC SUSPENSION FOR THE NIST VACUUM-TO-AIR MASS DISSEMINATION SYSTEM

September 3, 2015
Author(s)
Corey A. Stambaugh, Edward C. Mulhern, Eric C. Benck, Zeina J. Kubarych, Patrick J. Abbott
The redefined kilogram will be realized in vacuum and a method will be required to disseminate the standard to air. NIST has been developing a magnetic suspension system for this purpose. This paper discusses the progress to characterize and improve the

Optimizing Data Logger Setup for Vaccine Temperature Monitoring

September 1, 2015
Author(s)
Michal J. Chojnacky, Luis Chaves Santacruz, W Wyatt Miller, Gregory F. Strouse
Accidental freezing of refrigerated vaccine represents a significant public and private healthcare cost. Freeze-damaged vaccines lose their effectiveness, putting communities at risk. U.S. immunization programs have strengthened vaccine storage and

Test of a virtual cylindrical acoustic resonator for determining the Boltzmann constant

August 19, 2015
Author(s)
XiaoJuan Feng, Hong Lin, Keith A. Gillis, Michael R. Moldover, Jintao Zhang
We report progress in determining the Boltzmann constant k B using a virtual acoustic resonator derived by combining the measured frequencies of the longitudinal acoustic modes of two argon-filled, cylindrical, cavity resonators in such a way as to

Additive Manufacturing Round Robin Protocols: A Pilot Study

August 12, 2015
Author(s)
Shawn P. Moylan, Joshua Land, Antonio M. Possolo
As the number of users of additive manufacturing (AM) steadily increases, and considering their demand for material and process specifications, the need for standard protocols for round robin studies is increasing accordingly. Researchers at the National

Dew-point Measurements For Water In Compressed Carbon Dioxide

August 6, 2015
Author(s)
Christopher W. Meyer, Allan H. Harvey
When transporting CO2 for sequestration, it is important to know the water dew point in order to avoid condensation that can lead to corrosion. We have constructed a flow apparatus to measure the water content at saturation in a compressed gas. A saturator

Measuring Systematic and Random Error in Digital Forensics

July 24, 2015
Author(s)
Alexander J. Nelson, Simson L. Garfinkel
Recognized sources of error in digital forensics include systematic errors arising from implementation errors, and random errors resulting from faulty equipment. But as digital forensic techniques expand to include statistical machine learning, another

Development of an Ultra-Pure, Carrier-Free 209Po Solution Standard

July 23, 2015
Author(s)
Ronald Colle, Ryan P. Fitzgerald, Lizbeth Laureano-Perez
Ultra-pure, carrier-free 209Po solution standards have been prepared and standardized for their massic alpha-particle emission rate. The standards, which will be disseminated by the National Institute of Standards and Technology (NIST) as Standard

Techniques to Evaluate Laser Scanners for Advanced Manufacturing Applications

July 23, 2015
Author(s)
Prem K. Rachakonda, Balasubramanian Muralikrishnan, Katharine M. Shilling, Daniel S. Sawyer, Geraldine S. Cheok, Kamel S. Saidi
Laser scanners have become indispensable tools for fast and accurate 3D image acquisition applications such as part inspection, reverse engineering, cultural heritage digitization, surveying, automotive robotic navigation etc. The Dimensional Metrology

Infrared Imaging and Spectroscopy Beyond the Diffraction Limit

July 22, 2015
Author(s)
Andrea Centrone
Progress in nanotechnology is enabled by and dependent on the availability of measurement methods with spatial resolution commensurate with nanomaterials’ length scales. Chemical imaging techniques, such as scattering scanning near-field optical microscopy

Analysis of the Boundary Conditions of the Spline Filter

July 21, 2015
Author(s)
D Ott, Hao H. Zhang, Daniel B. Ott, Xuezeng Zhao, Jun-Feng Song
The spline filter is a standard linear profile filter recommended by ISO/TS 16610-22 (2006). The primary advantage of the spline filter is that no end-effects occur as a result of the filter. The ISO standard also provides the tension parameter β=0.62524

Robotic Spherical Near-Field Measurements at 183 GHz

July 21, 2015
Author(s)
Michael H. Francis, Ronald C. Wittmann, David R. Novotny, Joshua A. Gordon
We describe millimeter-wave near-field measurements made with the new National Institute of Standards and Technology (NIST) robotic scanning system. This system is designed for high-frequency performance, is capable of scanning in multiple configurations

Challenges to the use of the GUM

July 15, 2015
Author(s)
Steven D. Phillips
Presentation at the BIPM on (1) Issues with the uncertainty evaluation associated with the calibration of indicating instruments; and (2) the growing problem with “outlier rejection” in measurements with measurands defined by “extreme values”

MEMS optomechanical accelerometry standards

July 8, 2015
Author(s)
Felipe Guzman, Yiliang Bao, Jason J. Gorman, John R. Lawall, Jacob M. Taylor, Thomas W. LeBrun
Current acceleration primary standards reach relative uncertainties of the order of 0.001 and consist of complex test facilities, typically operated at National Metrology Institutes. Our research focuses on the development of silicon mechanical oscillator

Optomechanical Motion Sensors

July 8, 2015
Author(s)
Felipe Guzman, Oliver Gerberding, John T. Melcher, Julian Stirling, Jon R. Pratt, Gordon A. Shaw, Jacob M. Taylor
Compact optical cavities can be combined with motion sensors to yield unprecedented resolution and SI-traceability in areas such as acceleration sensing and atomic force microscopy AFM, among others. We have incorporated Fabry-Perot fiber-optic micro

Interference and Coexistence of Wireless Systems in Critical Infrastructure

July 7, 2015
Author(s)
Galen H. Koepke, William F. Young, John M. Ladbury, Jason B. Coder
We examine interference and coexistence testing issues, test methods, and the need to update and develop new test methodologies related to the use of wireless devices in critical infrastructure systems. A case study on interference is presented along with

Scanning electron microscope measurement of width and shape of 10 nm patterned lines using a JMONSEL-modeled library

July 1, 2015
Author(s)
John S. Villarrubia, Andras Vladar, Bin Ming, Regis J. Kline, Daniel F. Sunday, Jasmeet Chawla, Scott List
The width and shape of 10 nm to 12 nm wide lithographically patterned SiO2 lines were measured in the scanning electron microscope by fitting the measured intensity vs. position to a physics-based model in which the lines’ widths and shapes are parameters

Using Check Standard Data to Simplify Uncertainty Estimates

July 1, 2015
Author(s)
Theodore D. Doiron
Uncertainty has proven difficult to implement in calibrations labs. The subject has mathematics and statistics that are part of normal scientific research but are seldom found among working metrologists in small calibration labs. There is, however, a
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