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Metrology

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Displaying 1651 - 1675 of 2718

The Calculation of Natural Gas Viscosity

August 14, 2009
Author(s)
Aaron N. Johnson, William Johansen
The calculation of natural gas viscosity has been implemented many different ways including the use of constants. Different methods of calculating natural gas viscosity may produce values with differences as large as 50%. Increasing natural gas prices

Reference measurements of Hydrogen's Dielectric Permittivity

August 10, 2009
Author(s)
James W. Schmidt, Michael R. Moldover, Eric F. May
We used a quasi-spherical cavity resonator to measure the relative dielectric permittivity ε r of H 2 at frequencies from 2.4 GHz to 7.3 GHz, at pressures up to 6.5 MPa, and at the temperatures 273 K and 293 K. The resonator was calibrated using auxiliary

High Definition Flow

August 1, 2009
Author(s)
John D. Wright, Michael R. Moldover
From pharmaceutical production to the natural gas market, exact flow measurements are critical. Here's how NIST helps keep us all on the same page.

Recent developments in large-scale dimensional metrology

July 30, 2009
Author(s)
G Peggs, P.G Maropoulos, E.B Hughes, Alistair Forbes, S Robson, M Ziebart, Bala Muralikrishnan
With ever-more demanding requirements for the accurate manufacture of large components, dimensional measuring techniques are becoming progressively more sophisticated. This review describes some of the more recently-developed techniques and the state-of

Measurement and Standards: The role of NIST

July 29, 2009
Author(s)
Kent B. Rochford
At NIST, said Dr. Rochford, "we are very broad, but we focus like a laser on measurement science." NIST also helps develop standards and promote technology. He called the institute "fairly small," with about 2,800 employees and almost that many affiliated

Degradation and Nanofiller Release of Polymer Nanocomposites Exposed to UV

July 15, 2009
Author(s)
Tinh Nguyen, Bastien T. Pellegrin, Alexander J. Shapiro, Xiaohong Gu, Joannie W. Chin
Nanofillers are increasingly used to enhance multifunctional properties of polymers. However, recent research suggests that nanomaterials may have a negative impact on the environmental health and safety. Since polymers are susceptible to photodegradation

Nanoscale Measurements with a Through-Focus Scanning-Optical-Microscope

July 15, 2009
Author(s)
Ravikiran Attota, Richard M. Silver, Thomas A. Germer
We present a novel optical technique that produces nanometer dimensional measurement sensitivity using a conventional optical microscope, by analyzing through-focus scanning-optical-microscope (TSOM) images obtained at different focus positions. In

Long-Term Performance of Nano-Filled Polymeric Materials: Effect of ZnO Nanoparticles on Photodegradation of a Waterborne Polyurethane Coating

July 8, 2009
Author(s)
Xiaohong Gu, Dongmei Zhe, Minhua Zhao, Guodong Chen, Nhieu Ly, Paul E. Stutzman, Li Piin Sung, Tinh Nguyen, Joannie W. Chin
Polymers are widely used as exterior coatings in buildings, bridges, aircrafts and automobiles for both protection and aesthetic purposes. However, the service life of the applied coatings is limited due to the photodegradation of polymers induced by

Certification Report for SRM 2112 and 2113

July 1, 2009
Author(s)
Christopher N. McCowan
This report documents the procedures used to develop certified maximum force and absorbed energy values for SRM 2112 and SRM 2113. The report serves to provide outside observers with accurate and detailed information on how the materials were certified and

Economics of Measurement Uncertainty and Tolerances

July 1, 2009
Author(s)
Steven D. Phillips, J.M. Baldwin, William T. Estler
Productivity is considered by considering Cobb-Douglas production function and focusing on total factor productivity (TFP). We argue that developed economies like the United States need to develop TFP by utilizing advances in computation power and insights

Sensitivities and Variances for Fitted Parameters of Spheres

July 1, 2009
Author(s)
Christoph J. Witzgall, Marek Franaszek
Experimental data have been gathered by applying 3D imaging systems, such as LIDAR/LADAR instruments, to spherical objects. This report provides a compilation of the statistical and analytical procedures to be used for an evaluation, to be reported

The 2008 NCSLi Josephson Voltage Standards Interlaboratory Comparison

July 1, 2009
Author(s)
Harold V. Parks, William B. Miller, Leonard P. Pardo, Curtis Kiser, Clark A. Hamilton, Yi-hua D. Tang, Barry M. Wood
Josephson voltage standards (JVS) provide a highly accurate representation of the volt. Although the Josephson Effect provides an intrinsic standard of voltage, inter-comparisons between different systems are important to insure that potential sources of

Inter-Laboratory Comparisons of NbTi Critical Current Measurements

June 22, 2009
Author(s)
Arno Godeke, D. Turrioni, T. Boutboul, Najib Cheggour, A. K. Ghosh, Loren F. Goodrich, M Meinesz, A. den Ouden
We report on a multi-institute comparison of critical current data, measured on a modern Large Hadron Collider (LHC) NbTi wire that has shown a standard deviation below 1% in critical current density spread in more than 1500 measurements. Inter-laboratory

Test Results of the First US ITER TF Conductor in SULTAN

June 22, 2009
Author(s)
Nicolai N. Martovetsky, Daniel R. Hatfield, John R. Miller, Chen-yu Gung, Joel S. Schultz, Najib Cheggour, Loren F. Goodrich, Pierluigi Bruzzone, Boris Stepanov, Rainer Wesche, Bernd Seeber
The US Domestic Agency is one of six parties supplying TF cable-in-conduit conductors (CICCs) for ITER. Previous tests have shown that measured performance of the TF CICCs can be much lower than expected from the strand properties at the projected uniaxial

Precision ranging LIDAR using femtosecond fiber lasers

June 17, 2009
Author(s)
Nathan R. Newbury, Ian R. Coddington, William C. Swann
We discuss a coherent laser radar that uses two coherent femtosecond fiber lasers to perform absolute ranging at long distance. One coherent femtosecond fiber lasers acts as a source and the other as a local oscillator for heterodyne detection of the

Effect of Dissolved Nitrogen Gas on the Density of Di-2-Ethylhexyl Sebacate: Working Fluid of the NIST Oil Ultrasonic Interferometer Manometer Pressure Standard

June 1, 2009
Author(s)
Jay H. Hendricks, Jacob R. Ricker, Justin H. Chow, Douglas A. Olson
The National Institute of Standards and Technology (NIST) Low Pressure Manometry Laboratory maintains national pressure standards ranging from 1 mPa to 360 kPa through the operation of four ultrasonic interferometer manometer (UIM) pressure standards. NIST
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