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Displaying 22676 - 22700 of 73929

Guidelines for Access Control System Evaluation Metrics

September 14, 2012
Author(s)
Chung Tong Hu, Karen Scarfone
The purpose of this document is to provide Federal agencies with background information on access control (AC) properties, and to help access control experts improve their evaluation of the highest security AC systems. This document discusses the

Search for a T-odd, P-even Triple Correlation in Neutron Decay

September 14, 2012
Author(s)
Jeffrey S. Nico, T E. Chupp, K P. Coulter, R L. Cooper, S. J. Freeman, B. K. Fujikawa, A. Garcia, Gordon L. Jones, Hans P. Mumm, Alan K. Thompson, C A. Trull, F. E. Wiefeldt, J. F. Wilkerson
Time-reversal-invariance (T) violation, or equivalently, assuming charge-conjugation-parity-time-reversal (CPT) invariance, CP violation may explain the observed cosmological baryon asymmetry as well as signal physics beyond the Standard Model. In the

UV-induced photochemical transformations of citrate capped silver nanoparticle suspensions

September 14, 2012
Author(s)
Justin M. Gorham, Robert I. MacCuspie, Kate L. Klein, D H. Fairbrother, Richard D. Holbrook
Due to the increasing use of silver nanoparticles (AgNPs) in consumer products, it is essential to understand how variables, such as light exposure, may change the physical and chemical characteristics of AgNP suspensions. To this end, the effect of 300 nm

Density and Speed of Sound Measurements of Four Bio-derived Fuels

September 13, 2012
Author(s)
Stephanie L. Outcalt, Tara J. Fortin
Compressed-liquid densities and ambient pressure densities and speeds of sound of four biomass-derived fuels have been measured. The compressed-liquid measurements were made from 270 K to 470 K, and 0.5 MPa to 50 MPa. The ambient pressure measurements were

Measuring Combinatorial Coverage of System State-space for IV&V

September 13, 2012
Author(s)
David R. Kuhn, Raghu N. Kacker
This report describes some measures of combinatorial coverage that can be helpful in estimating this risk that we have applied to tests for spacecraft software but have general application to any combinatorial coverage problem. This method will be

Near-field Calibration of an Objective Spectrophotometer to NIST Radiometric Standards for the Creation and Maintenance of Standard Stars for Ground- and Space-Based Applications

September 13, 2012
Author(s)
John T. Woodward IV, Keith R. Lykke, Claire E. Cramer, John T. McGraw, Peter Zimmer, Daniel C. Zirzow, Susana Deustua, Dean Hines
NIST-calibrated detectors will be used by the ground-based 100mm diameter Astronomical Extinction Spectrophotometer (AESoP) to calibrate the spectral energy distributions of bright stars to sub-1% per 1nm spectral resolution element accuracy. AESoP will

Soil-Structure Interaction for Building Structures

September 13, 2012
Author(s)
Jonathan Stewart, C.B. Crouse, Tara C. Hutchinson, Bret Lizundia, Farzad Naeim, Farhang Ostadan
The purpose of this project was to develop consensus guidance for implementing soil-structure interaction in response history analyses, and to identify areas of further research that were needed. The starting point for this work was decades of available

Tunable Laser Techniques for Improving the Precision of Optical Astronomy

September 13, 2012
Author(s)
Keith R. Lykke, Claire E. Cramer, John T. Woodward IV, Steven W. Brown, Ping-Shine Shaw
Improving the precision of optical astronomy requires not only new telescopes and instrumentation, but also advances in observing protocols, calibrations and data analysis. The Laser Applications Group at the National Institute of Standards and Technology

Zero-energy modes and gate-tunable gap in graphene on hexagonal boron nitride

September 13, 2012
Author(s)
Markus Kindermann, Bruno Uchoa, David L. Miller
In this article, we derive an effective theory of graphene on a hexagonal boron nitride (h-BN) substrate. We show that the h-BN substrate generically opens a spectral gap in graphene despite the lattice mismatch. The origin of that gap is particularly

Cross-View Action Recognition via a Transferable Dictionary Pair

September 12, 2012
Author(s)
P J. Phillips, Jingjing Zheng, Zhuolin Jiang, Rama Chellappa
Discriminative appearance features are effective for recognizing actions in a fixed view, but generalize poorly to changes in viewpoint. We present a method for view- invariant action recognition based on sparse representations using a transferable dictio-

Electron Microscopy, Nanoscopy and Scanning Micro- and Nanoanalysis

September 12, 2012
Author(s)
Vladimir P. Oleshko, Renaat Gijbels, Severin Amelinckx
The paper considers history and stages of development of electron microscopy (EM) and scanning microanalysis, including theoretical aspects of electron beam-solid interactions, instrumentation, methodology of particular techniques and image analysis

Giant electrocaloric effect in ferroelectric poly(vinylidenefluoride-trifluoroethylene) copolymers near a first order transition

September 12, 2012
Author(s)
Fred B. Bateman, Xinyu Li, Xiaoshi Qian, Haiming Gu, Xiangzhong Chen, Sheng-Guo Lu, Minren Lin, Qiming Zhang
We present directly measured electrocaloric effect (ECE) from the P(VDF-TrFE) 65/35 mol% copolymer which displays a first order FE-PE transition. The data reveal that there is a large difference in the ECE between that measured in applying field and in

Justification of Shielding Requirements for Plutonium Sources

September 12, 2012
Author(s)
Leticia S. Pibida, Michael P. Unterweger
This report provides a justification for shielding plutonium sources when testing radiation detection instruments against standard performance requirements and test methods. The use of copper as a shielding material is proposed to provide comparable test

Measurements of Infrared Spectral Directional Emittance at NIST - A Status Update

September 12, 2012
Author(s)
Boris Wilthan, Leonard Hanssen, Sergey Mekhontsev
Over the past two decades, the Sensor Science Division at the National Institute of Standards and Technology (NIST) has developed extensive capabilities for the characterization of the infrared optical properties of materials and components. These include

Renormalization of the graphene dispersion velocity determined from scanning tunneling spectroscopy

September 11, 2012
Author(s)
Joseph A. Stroscio, Jungseok Chae, Nikolai B. Zhitenev, Suyong Jung, Andrea F. Young, Cory Dean, Yuanda Gao, Kenji Watanabe, Takashi Taniguchi, James Hone, Kenneth L. Shepard, Philip Kim, Lei Wang
In most metals, electrons behave as non-interacting quasiparticles with renormalized dynamical properties in the presence of electron interactions. Historically, many measurements are capable to probe the effect of interactions at the Fermi energy

An Argument for Virtual Testing in the Cement Plant

September 10, 2012
Author(s)
Pichet Sahachaiyunta, Kittisak Pongpaisanseree, Jeffrey W. Bullard, Paul E. Stutzman, Edward Garboczi, Wilasa Vichit-Vadakan
The cement industry is moving toward customized commodity products, requiring plants that were built to consistently produce thousands of tons of one product each day to now be versatile enough to fine-tune multiple products that meet both industry
Displaying 22676 - 22700 of 73929
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