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NIST Authors in Bold

Displaying 4601 - 4625 of 74068

Iris Recognition on Noah Kalina's Everyday

April 26, 2021
Author(s)
James Matey
In January 2000, Noah Kalina began taking a photograph of himself every day – and has continued for more than 20 years. A time-lapse video of his images can be seen online: EveryDay. These images, and images from similar projects, provide us with

Sequence-based U.S. population data for 7 X STR loci

April 26, 2021
Author(s)
Lisa Borsuk, Carolyn R. Steffen, Kevin M. Kiesler, Peter Vallone, Katherine Gettings
The National Institute of Standards and Technology (NIST) U.S. population sample set of unrelated individuals was used to determine allele and haplotype frequencies for seven X-chromosome short tandem repeat (STR) loci in four linkage groups. DXS7132

Outgassing rate comparison of seven geometrically similar vacuum chambers of different materials and heat treatments

April 23, 2021
Author(s)
James A. Fedchak, Julia Scherschligt, Sefer Avdiaj, Daniel Barker, Stephen Eckel, Ben Bowers, Scott O'Connell, Perry Henderson
We have measured the water and hydrogen outgassing rates of seven vacuum chambers of identical geometry but constructed of different materials and heat treatments. Chambers of five different materials were tested: 304L, 316L, and 316LN stainless steels

Automated Piston Gauge Calibration System.

April 22, 2021
Author(s)
Julia Scherschligt, Yuanchao Yang, Katie M. Schlatter, Robert G. Driver, Christina D. Cross, John S. Quintavalle
Piston gauges or pressure balances are important primary standards for the realization of the SI unit of pressure, the Pascal. The National Institute of Standards and Technology (NIST) operates and maintains a calibration service for these devices, and has

Blackbody Radiation Noise Broadening of Quantum Systems

April 22, 2021
Author(s)
Eric B. Norrgard, Stephen Eckel, Christopher L. Holloway, Eric L. Shirley
Precision measurements of quantum systems often seek to probe or must account for the interaction with blackbody radiation. Over the past several decades, much attention has been given to AC Stark shifts and stimulated state transfer. For a blackbody in

CALIBRATION OF SPECTRORADIOMETERS USING TUNABLE LASERS

April 22, 2021
Author(s)
Yuqin Zong, Ping-Shine Shaw, Joseph Rice, C Cameron Miller
To shorten the long calibration chain when using the conventional source-based approach and therefore to reduce spectroradiometer's calibration uncertainty, we developed a detector-based approach to calibrate spectroradiometers directly against a transfer

Depolarization in diffusely scattering media

April 22, 2021
Author(s)
Thomas A. Germer
We performed Mueller matrix Monte Carlo simulations of the propagation of optical radiation in diffusely scattering media for collimated incidence and report depolarization in the the transmitted rays as a function of thickness, the angle subtended by the

Discovering Critical KPI Factors from Natural Language in Maintenance Work Orders

April 22, 2021
Author(s)
Michael Sharp, Michael Brundage, Rachael Sexton, Fnu Madhusudanan Navinchandran
Optimizing maintenance practices is a continuous process that must take into account the evolving state of the equipment, resources, workers, and more. To help streamline this process, facilities need a concise procedure for identifying critical tasks and

Quantum Blackbody Thermometry

April 22, 2021
Author(s)
Eric B. Norrgard, Stephen Eckel, Christopher L. Holloway, Eric L. Shirley
Blackbody radiation (BBR) sources are calculable radiation sources that are frequently used in radiometry, temperature dissemination, and remote sensing. Despite their ubiquity, blackbody sources, have a plethora of systematics (e.g., emissivity

Recent research and development in photometry at NIST

April 22, 2021
Author(s)
Yuqin Zong, Maria Nadal, Benjamin K. Tsai, C Cameron Miller
Many developments were made in recent years in photometry at NIST for reducing measurement uncertainties, increasing calibration efficiencies, and adding measurement capabilities. The 40 years old photometry laboratory has been renovated. The new

Spatial frequency domain Mueller matrix imaging

April 22, 2021
Author(s)
Joseph Chue-Sang, Aaron Goldfain, Jeeseong C. Hwang, Thomas A. Germer
We combine Mueller matrix polarimetry (MMP) with spatial frequency domain imaging (SFDI) to create a technique that is sensitive to near-surface material anisotropy. We demonstrate this imaging modality with scattering and absorbing phantoms and with a

STANDARD LEDS WITH SUPERIOR LONG-TERM STABILITY

April 22, 2021
Author(s)
Yuqin Zong, Weiqiang Zhao, C Cameron Miller
A large-chip standard LED with superior long-term stability have been developed at NIST. The standard LED uses a large, specialty die rated for 50 W but is operated under 3 W to eliminate aging effect. The standard LED was seasoned for one year and

Superconductivity in Co-Layered LaCoSi

April 22, 2021
Author(s)
Zhengwen He, Rongjin Huang, Kaiyao Zhou, Ye Liu, Shibin Guo, Yuzhu Song, Zhongnan Guo, Shuxian Hu, Lunhua He, Qingzhen Huang, Laifeng Li, Jingyan Zhang, Shouguo Wang, Jiangang Guo, Xianran Xing, Jun Chen

A portable triaxial cell for beamline imaging of rocks under triaxial state of stress

April 21, 2021
Author(s)
Amer Syed, Yukie Tanino, Jacob LaManna, David L. Jacobson, Daniel S. Hussey, Eli Baltic, Genoveva Burca
With recent developments in direct imaging techniques using x-ray and neutron imaging, there is an increasing need for an efficient design of a test setup to study mechanical and/or the transport behaviour of porous rocks. Bespoke design from commercial

Accurate measurement of the through-plane water content of proton-exchange membranes using neutron radiography

April 21, 2021
Author(s)
Daniel S. Hussey, David L. Jacobson, Dusan Spernjak, Adam Weber, Rangachary Mukundan, Joseph Fairweather, Eric Brosha, John Davey, Jacob Spendelow, Rodney Borup
The water sorption of proton-exchange membranes (PEMs) was measured in situ using high-resolution neutron imaging in small-scale fuel-cell test sections. A detailed characterization of the measurement uncertainties and corrections associated with the

Average Soil Water Retention Curves Measured by Neutron Radiography

April 21, 2021
Author(s)
Daniel S. Hussey, David L. Jacobson, Chu-lin Cheng, Misun Kang, Juske Horita, sophie voisin, Hassina Bilheux, Warren Jeffery, Edward Perfect
Water retention curves are essential for understanding the hydrologic behavior of partially- saturated porous media and modeling flow transport processes within the vadose zone. In this paper we report direct measurements of the main drying and wetting
Displaying 4601 - 4625 of 74068