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Displaying 1126 - 1150 of 2964

Neutron Images of the Through-Plane Water Distribution of an Operating PEM Fuel Cell

July 27, 2007
Author(s)
Daniel S. Hussey, David L. Jacobson, Muhammad Arif, Jon P. Owejan, Jeffrey J. Gagliardo, T Trabold
Neutron imaging has proven an invaluable tool for water metrology in operating proton exchange membrane fuel cells. Due to limitations in scintillator-based detector resolution, neutron imaging has been applied only to assessing the in-plane water

Residual stress determination by diffraction: Modeling and applications

January 1, 2004
Author(s)
Davor Balzar, N C. Popa
Residual stress plays an important role in shaping Iilaterials properties. We present both the method to determine texture-weighted strain orientation distribution function for arbitrary crystal and sample symmetries and an example of the determination of

Metallurgical Analysis of Wrought Iron From the RMS Titanic

April 1, 2003
Author(s)
J J. Hooper, Timothy J. Foecke, L Graham, Timothy P. Weihs
The discovery of the RMS Titanic has led to a number of scientific studies, one of which addresses the role that structural materials played in the sinking of the ship. Early studies focused on the quality of the hull steel as a contributing role to the

Wall Migration and Shear-Induced Diffusion of Fluid Droplets in Emulsions

January 1, 2003
Author(s)
Steven D. Hudson
The spatial distribution of drops in multiphase flow through narrow passages is analyzed theoretically and experimentally. In simple shear between two plates, drops migrate away from the walls and concentrate towards the center of the gap. At steady state

Acoustic Study of Texture in Polycrystalline Brass

May 1, 1999
Author(s)
K Foster, S L. Fairburn, R G. Leisure, Sudook A. Kim, Davor Balzar, G A. Alers, H M. Ledbetter
Resonant ultrasonic spectroscopy was used to measure the orthorhombic elastic constants of rolled, polycrystalline plates of Cu, Cu - 5% Zn, and Cu - 15% Zn. The experimental results were in good agreement with theory for the Cu and the Cu-15% Zn materials

Optical Microwave Frequency Stability: Some Constraints

July 25, 2005
Author(s)
Leo W. Hollberg, Scott A. Diddams, A Bartels, John J. McFerran, Eugene N. Ivanov, G Wilpers, Christopher W. Oates
Optical frequency references achieve the best frequency stability of any oscillators by taking advantage of high Q = υ 0/{Δ}υ optical resonances. These systems are beginning to run into fundamental and technical limitations which are discussed.

4-bar-quasi-phasematching for second-harmonic generation in microdisks

August 15, 2011
Author(s)
Paulina S. Kuo, Glenn S. Solomon
We present a theoretical description of resonantly enhanced, 4-bar-quasi-phasematched, second-harmonic generation in microdisks made of materials possessing 4-bar symmetry, such as GaAs, GaP and ZnSe. The theory describes the interplay between quasi

2 Combinatorial Methods Polymer Science: Synthesis and Characterization

November 1, 2001
Author(s)
J C. Meredith, A P. Smith, Alamgir Karim, Eric J. Amis
Combinatorial methodologies offer the ability to efficiently measure relevant chemical and physical properties over lare regimes of varible space. We review recent work in the development of combinatorial methods for polymer synthesis and characterization

Persistent photoconductivity studies of c-axis GaN nanowires grown by MBE

September 16, 2007
Author(s)
Norman Sanford, Paul T. Blanchard, Kristine A. Bertness, Alexana Roshko, Beau Burton, Lorelle Mansfield, John B. Schlager, Steven George, Aric Sanders
Photoconductivity (PC) and persistent photoconductivity (PPC) were measured on c-axis GaN nanowires (NWs) grown by catalyst-free nitrogen plasma assisted MBE on Si(111) substrates. Unintentionally doped n-type NWs from two separate growth batches were

Vibration-induced field fluctuations in a superconducting magnet

June 27, 2016
Author(s)
Joseph W. Britton, John J. Bollinger, Justin G. Bohnet, Brian C. Sawyer, Hermann Uys, Michael Biercuk
Superconducting magnets enable precise control of nuclear and electron spins, and are used in experiments that explore biological and condensed matter systems, and fundamental atomic particles. In high-precision applications, a common view is that that

Pulse Metrology, Part II

June 1, 2012
Author(s)
Nicholas G. Paulter Jr., Donald R. Larson
Pulse metrology refers to the science of the measurement of pulses, which are transient phenomena. This article describes concepts important for pulse metrology, namely, reproducibility and repeatability of measurement, measurement uncertainty, and

Pulse Metrology, Part 1

June 1, 2011
Author(s)
Nicholas G. Paulter Jr., Donald R. Larson
Pulse metrology refers to the science of the measurement of pulses, which are transient phenomena. This article describes concepts important for pulse metrology, namely, reproducibility and repeatability of measurement, measurement uncertainty, and

Practical performance limits on optical frequency transfer over fiber optic links

May 4, 2008
Author(s)
Paul A. Williams, William C. Swann, Nathan R. Newbury
We present theory and experiment quantifying the limitations to stable transport of optical frequencies over optical fiber. These are fundamental fiber noise, propagation delay, bidirectional propagation and system noise in the measurement interferometers.
Displaying 1126 - 1150 of 2964
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