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Displaying 801 - 825 of 1845

Quantum Dot Dissemination and Behavior in Bacterial Biofilms

May 7, 2006
Author(s)
Jayne B. Morrow, Richard D. Holbrook, Cynthia J. Zeissler
Quantum dots (QDs) are colloidal semiconductor nanocrystals that photoluminescence emission is proportional to the dot size and have been utilized in fluorescent imaging in biological systems. Biofilms are communities of microorganisms attached to surfaces

Regenerator Operation at Very High Frequencies for Microcryocoolers

April 27, 2006
Author(s)
Ray Radebaugh, Agnes A. O'Gallagher
The size of Stirling and Stirling-type pulse tube cryocoolers is dominated by the size of the pressure oscillator. Such cryocoolers typically operate at frequencies up to about 60 Hz for cold-end temperatures above about 60 K. Higher operating frequencies

Ionizing Radiation-Induced Destruction of Benzene and Dienes in Aqueous Media

March 28, 2006
Author(s)
M I. Al-Sheikhly, Dianne L. Poster, Jung-Chul An, Pedatsur Neta, Joseph Silverman, Robert E. Huie
Pulse radiolysis with spectrophotometric and conductometric detection was utilized to study the formation and reactions of radicals from benzene and dienes in aqueous solutions. The benzene OH adduct, C6H6OH, reacts with O2 (k = 3 x 108 L mol-1 s-1) in a

Consistency of D 13 C Measurements Improved

February 1, 2006
Author(s)
T B. Copelen, W Brand, M Gehre, M Groening, HAJ Meijer, Blaza Toman, R. Michael Verkouteren
We present state-of-the-art measurements and data evaluation methods to show that the consistency of carbon isotope ratio measurements can be improved 39 % to 47 % by anchoring the measurement scale with two isotopic reference materials differing in carbon

Preparation of Reference Material 8504, Transformer Oil

February 1, 2006
Author(s)
Dianne L. Poster, Michele M. Schantz, Stephen A. Wise
A new reference material (RM), RM 8504, has been prepared for use as a diluent oil with Aroclors in transformer oil Standard Reference Materials (SRMs) 3075-3080 or SRM 3090 when developing and validating methods for the determination of polychlorinated

Reducing Uncertainty in Particle Size Measurement for Liquid Filter Testing

January 1, 2006
Author(s)
Barry M. Verdegan, Robert A. Fletcher
Contamination control is essential to reliable, cost-effective operation of hydraulic and engine systems. Particle counting provides the common, underlying basis for comparing filter performance and monitoring of contamination levels in hydraulic oil, lube

Relaxation Effects in Small Critical Nozzles

January 1, 2006
Author(s)
Aaron N. Johnson, C L. Merkle, Michael R. Moldover, John D. Wright
We computed the flow of four gases (He, N 2, CO 2, and SF 6) through a critical nozzle by augmenting traditional computational fluid dynamics (CFD) with a rate equation that accounts for τ relax, a species-dependent relaxation time that characterizes the

Polycyclic Aromatic Hydrocarbons in Flames, in Diesel Fuels, and in Diesel Emissions

December 1, 2005
Author(s)
R Dobbins, Robert A. Fletcher, Bruce A. Benner Jr., S Hoeft
Numerous chemical analyses of gaseous and particulate samples from laboratory flames provide a library of data on the polycyclic aromatic hydrocarbons (PAH) species found in diverse flame types burning fuels consisting of pure gaseous hydrocarbons. Diesel

Correlation Charts for Ultraviolet-Visible Spectrophotometry

October 31, 2005
Author(s)
Thomas J. Bruno, Paris D. Svoronos
This section provides correlation charts and operational information for the design and interpretation of ultraviolet spectrophotometric (UV-Vis) measurements. While UV-Vis. is perhaps not as information-rich as infrared or nuclear magnetic resonance, it
Displaying 801 - 825 of 1845