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Displaying 1551 - 1575 of 2724

Degradation and Nanoparticle Release of Nanocomposite Coatings Exposed to UV Radiation

June 2, 2010
Author(s)
Tinh Nguyen, Bastien T. Pellegrin, Coralie Bernard, Xiaohong Gu, Justin M. Gorham, Paul E. Stutzman, Alexander J. Shapiro, Walter E. Byrd, Joannie W. Chin
The release of nanoparticles from nanocomposite coatings during their life cycle potentially has negative effects to the environments and presents a roadblock to their uses. The degradation and nanoparticle release of amine-cured epoxy coatings containing

Cylindrical Acoustic Resonator for the Re-determination of the Boltzmann Constant

June 1, 2010
Author(s)
J.T. Zhang, H. Lin, X.J. Feng, Keith A. Gillis, Michael R. Moldover
We describe progress towards re-determining the Boltzmann constant k B using two fixed-path, gas-filled, cylindrical, acoustic cavity resonators. The longitudinal acoustic resonance modes of a cylindrical cavity have lower quality factors Q than the radial

Feasibility of an Accurate Dynamic Standard for Water Flow

June 1, 2010
Author(s)
Iosif I. Shinder, Michael R. Moldover
We used NIST's primary water flow standard to study the feasibility of accurately determining mass flow rates m dot of water "dynamically," that is from the time derivative of the weight W of the collection tank: m dot,dynamic = (dW/dt)/g. When data for a

Standard Reference Materials for Analysis of Dietary Supplements

June 1, 2010
Author(s)
Katherine E. Sharpless, David L. Duewer
NIST, in collaboration with the National Institutes of Health Office of Dietary Supplements (NIH-ODS) and the Food and Drug Administration (FDA) is producing Standard Reference Materials (SRMs) for dietary supplements. This paper describes the how these

Modeling and metrology of metallic nanowires with application to microwave interconnects

May 23, 2010
Author(s)
Kichul Kim, Thomas M. Wallis, Paul Rice, Chin J. Chiang, Atif A. Imtiaz, Pavel Kabos, Jintao Zhang
Abstract: Broadband characterization of individual metallic nanowires for microwave interconnect applications is discussed. Circuit and method of moments (MoM) modeling are benchmarked using a set of coplanar waveguide (CPW) test devices with microwire Au

Simultaneous XAFS Measurements of Multiple Samples

May 17, 2010
Author(s)
Bruce D. Ravel, C. Scorzato, D. P. Siddons, S. D. Kelly, S. R. Bare
A four-channel ionization chamber has been designed, constructed and tested. This ionization chamber allows X-ray absorption spectra to be collected in transmission from up to four samples simultaneously. This results in spectra that are free of systematic

Uncertainty Budgeting for Range Calibration

May 10, 2010
Author(s)
Ruediger Kessel, Raghu N. Kacker, Klaus-Dieter Sommer
The Guide to the Expression of Uncertainty (GUM) in Measurement established a general procedure to evaluate measurement uncertainty. The Guide covers only the evaluation of a single result or a set of results. Modern measurement instruments and procedures

Solutions for Determining Equibiaxial Substrate Strain for Dynamic Cell Culture

May 2, 2010
Author(s)
Martin Y. Chiang, Tianle Cheng, Lisa Pakstis, Joy P. Dunkers
Empirical and analytical solutions are derived in this study to determine the equibiaxial strain on a flexible substrate upon which the cells can be cultured. The empirical formula is based on the mechanistic constraint and a regression analysis of results

NEXT GENERATION GUARDED HAMON TRANSFER STANDARDS FOR HIGH RESISTANCE

May 1, 2010
Author(s)
Dean G. Jarrett, Andrew J. Dupree
Guarded Hamon transfer standards have been used at NIST for decades for scaling to high resistance levels. A recent project has been undertaken to apply improved designs in guarded Hamon transfer standards to the 1 MΩ to 100 MΩ ranges with the larger goal

Code-division SQUID multiplexing

April 23, 2010
Author(s)
Michael D. Niemack, Kent D. Irwin, Joern Beyer, Hsiao-Mei Cho, William B. Doriese, Gene C. Hilton, Carl D. Reintsema, Daniel R. Schmidt, Joel N. Ullom, Leila R. Vale
Multiplexed superconducting quantum interference device (SQUID) readout systems are a critical technology for measuring large arrays of superconducting transition-edge sensor (TES) detectors. Current successful SQUID multiplexing architectures are

NIST Calibration Services for Hydrometers.

April 19, 2010
Author(s)
John D. Wright, Vern E. Bean
The National Institute of Standards and Technology (NIST) provides calibration services for hydrometers used to measure liquid density. Hydrometers with scales for density, specific gravity, proof spirit for alcohol solutions, API degrees for petroleum

Applications of Cross-Correlation Functions

April 14, 2010
Author(s)
Theodore V. Vorburger, Jun-Feng Song, Wei Chu, Li Ma, Xiaoyu A. Zheng, Thomas B. Renegar, Son H. Bui
We describe several examples where we use cross-correlation functions to quantify the similarity of 2D surface profiles or of 3D surface topography images. The applications have included 1) the manufacture of Standard Reference Material (SRM) bullets and

Direct Evidence of Nanoparticle Release from Epoxy Nanocomposites Exposed to UV Radiation

April 14, 2010
Author(s)
Tinh Nguyen, Bastien T. Pellegrin, Coralie Bernard, Xiaohong Gu, Justin M. Gorham, Paul E. Stutzman, Alexander J. Shapiro, Walter E. Byrd, Joannie W. Chin
This study assessed the fate of SiO2 nanoparticles (nanoSiO2) in epoxy/nanoSiO2 composites exposed to ultraviolet (UV) radiation. The matrix was a stoichiometric mixture of adiglycidyl ether of bisphenol A epoxy and an aliphatic tri-amine. Films of

Performance of Critical Flow Venturis under Transient Conditions

April 13, 2010
Author(s)
John D. Wright
Critical flow venturis (CFVs) can be used to measure flow under transient pressure and flow conditions with uncertainties of 0.13 % or less (95 % confidence level). Blow-down tests transferred 630 g of nitrogen during a 100 s interval from an unregulated

A Second-Generation NIST Gravimetric Hygrometer

April 1, 2010
Author(s)
Christopher W. Meyer, Joseph T. Hodges, Gregory E. Scace, James R. Whetstone, R W. Hyland
A second-generation primary hygrometer has been completed at the National Institute of Standards and Technology (NIST). A gravimetric hygrometer measures humidity by separating the water from the carrier gas using desiccants and afterwards independently

Adhesion research at the National Institute of Standards and Technology (NIST)

April 1, 2010
Author(s)
Christopher M. Stafford, Adam J. Nolte, Gale A. Holmes, Sheng Lin-Gibson, John A. Howarter
NIST s involvement in adhesion research has been wide ranging and is ultimately in response to interactions between individual project leaders and our industrial partners. In this way, NIST s participation in the Adhesion Society has been instrumental in
Displaying 1551 - 1575 of 2724
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