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Search Publications

NIST Authors in Bold

Displaying 26701 - 26725 of 73929

Comparison of Near-Field Methods at NIST

June 13, 2010
Author(s)
Katherine MacReynolds
A comparison of the planar, spherical and cylindrical near-field techniques was completed at the National Institute of Standards and Technology (NIST) for a Ku-band cassegrain reflector antenna. This paper discusses the measurement results for the near-to

Design of the NIST 10 V programmable Josephson voltage standard system

June 13, 2010
Author(s)
Charles J. Burroughs, Paul Dresselhaus, Alain Rufenacht, Mike Elsbury, Samuel Benz
NIST has developed and implemented a new Programmable Josephson Voltage Standard (PJVS) that operates at 10 V. This next-generation system is optimized for both dc metrology and stepwise-approximated ac voltage measurements for frequencies up to a few

Development and investigation of intrinsically shunted junction series arrays for ac Josephson voltage standards

June 13, 2010
Author(s)
Johannes Kohlmann, Franz Mueller, Oliver F. kieler, D. Schleussner, B Egeling, Ralf Behr, David I. Olaya, Paul Dresselhaus, Samuel Benz
Different types of intrinsically shunted Josephson junctions have been developed and inves¬tigated for ac voltage standard applications at PTB. The first type for generation of voltages up to 10 V is driven by a 70 GHz sinusoidal microwave signal and

Development of a Four-channel System for Johnson Noise Thermometry

June 13, 2010
Author(s)
Alessio Pollarolo, Jifeng Qu, Horst Rogalla, Paul Dresselhaus, Samuel Benz
Long integration time is necessary to reach low uncertainty when measuring temperature through Johnson Noise Thermometry (JNT). The main goal of the NIST JNT experiment is to achieve a 6 10-6 relative uncertainty in the measurement of the water triple

Error in calorimetric effective efficiency measurements due to DC losses

June 13, 2010
Author(s)
Thomas P. Crowley
A phenomenon in which DC loss in a transfer standard results in incorrect calorimetric effective efficiency measurements is described. The DC loss occurs within the 4-wire leads of the transfer standard or its connector. It therefore affects calorimetric

Establishing an ac Josephson voltage standard at NRC

June 13, 2010
Author(s)
Piotr S. Filipski, M. Boecker, Samuel Benz, Charles J. Burroughs
NRC recently established an AC Josephson Voltage Standard (ACJVS) system based on a NIST pulse-driven Josephson-junction array. This paper describes the efforts undertaken at NRC and the experience that was gained. An experimental method of measuring

Evaporator Optimization for Non-Uniform Air Distribution

June 13, 2010
Author(s)
Piotr A. Domanski, David A. Yashar, Sunil Lee
This study demonstrates the performance improvements that can be achieved by accounting for the in-situ air flow distribution during the design phase of a heat exchanger. The heat exchanger used in this study was a two-slab, A-shaped finned-tube evaporator

INTERCOMPARISON OF W-BAND STANDARD GAIN HORN ANTENNAS

June 13, 2010
Author(s)
Katherine MacReynolds, J. Kang, N. Kang, D. Gentle, Michael H. Francis
An intercomparison of power gain for W-band (75 GHz to 110 GHz) standard horn antennas has been performed among KRISS, NPL and NIST. This paper describes the comparison and its measurement results.

Microwave Optimization of 10 V PJVS Circuits

June 13, 2010
Author(s)
Paul D. Dresselhaus, Mike Elsbury, Charles J. Burroughs, Samuel P. Benz
Proper operation of programmable Josephson voltage standard arrays depends on the uniform distribution of microwaves to a large number of Josephson junctions. Too much or too little microwave power will change the current range of a junction s constant

Power Spectral Density: Is it right?

June 13, 2010
Author(s)
Ulf Griesmann, John Lehan, Jiyoung Chu
We concentrate on the instrumental issues surrounding power spectral density (PSD) determination, using as an example, the most common optical shop QA tool, the Fizeau interferometer. We briefly discuss the properties of an ideal calibration method for PSD

Quantifying How Lighting and Focus Affect Face Recognition Performance

June 13, 2010
Author(s)
J. R. Beveridge, David Bolme, Bruce A. Draper, Geof H. Givens, Yui M. Lui, P. Jonathon Phillips
Recent studies show that face recognition in uncontrolled images remains a challenging problem, although the reasons why are less clear. Changes in illumination are one possible explanation, although algorithms developed since the advent of the PIE and

Reduced Nonlinearities in the NIST Johnson Noise Thermometry System

June 13, 2010
Author(s)
Jifeng Qu, Samuel Benz, Alessio Pollarolo, Horst Rogalla
Improved electronics and synthesized noise waveforms for the NIST quantum-voltage-standard- calibrated Johnson noise thermometer (JNT) have lead to reduced uncertainty in the temperature measurement. Recent measurements show that some of the distortion in

Development and Demonstration of a Method to Evaluate Bio-Sampling Strategies Using Building Simulation and Sample Planning Software

June 10, 2010
Author(s)
William S. Dols, Jayne B. Morrow, Andrew K. Persily, Brett Matzke, Landon Sego, Lisa Nuffer, Brent Pulsipher
response and recovery sampling approaches and technologies, the U.S. Department of Homeland Security (DHS), along with several other agencies, have simulated a biothreat agent release within a facility at Idaho National Laboratory (INL) on two separate

Effects of fiber gripping methods on single fiber tensile test using Kolsky bar

June 10, 2010
Author(s)
Jae Hyun Kim, Richard L. Rhorer, Haruki Kobayashi, Walter G. McDonough, Gale A. Holmes
Preliminary data by Ming Cheng et al. indicate minimal impact of strain rate on the tensile stress-strain behavior of Kevlar. However, technical issues associated with specimen preparation appear to limit the number of samples and show an undesirable

From the bottom up measuring bulk mechanical properties via microtechnology

June 10, 2010
Author(s)
Nicholas Barbosa, Sudook A. Kim, David T. Read
The micromechanics community has developed a large set of tools for measuring the properties of micro- and nano-scaled materials. These new tools have been successfully applied to a range of materials, most often in thin-film form, to determine the

Occupant Behavior in a High-rise Office Building Fire

June 10, 2010
Author(s)
Erica D. Kuligowski, Bryan L. Hoskins
Survey responses from occupants involved in a 32-story high-rise building evacuation during an actual fire were collected and analyzed to study the pre-evacuation period. Multiple regression models were used to test whether specific occupant, building, and

Rationale of Color Quality Scale

June 10, 2010
Author(s)
Yoshihiro Ohno, Wendy L. Davis
The color quality of solid state lighting (SSL) products is critical and is the subject of increasing attention. The CIE Color Rendering Index (CRI) [1] has been widely used for many years. However, the CRI is 35 years old and various problems of the CRI

State of Security Readiness

June 10, 2010
Author(s)
Ramaswamy Chandramouli, Peter M. Mell
Cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources that can be rapidly provisioned and released with minimal management effort or service provider interaction. However, the
Displaying 26701 - 26725 of 73929
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