Search Publications

Displaying 526 - 550 of 2729

Lipid Concentrations in Standard Reference Material (SRM) 1950: Results from an Interlaboratory Comparison Exercise for Lipidomics

August 1, 2017

Author(s)

John Bowden, Candice Z. Ulmer, Christina M. Jones, Nathanael A. Heckert

No abstract

Progress on Vacuum-to-Air Mass Calibration System Using Magnetic Suspension to Disseminate the Planck-constant Realized Kilogram

July 31, 2017

Author(s)

Eric C. Benck, Corey A. Stambaugh, Edward C. Mulhern, Patrick J. Abbott, Zeina J. Kubarych

The kilogram is the unit of mass in the International System of units (SI) and has been defined as the mass of the International Prototype Kilogram (IPK) since 1889. In the future, a new definition of the kilogram will be based on precise measurements of

Photo-induced transformations of polyvinylpyrrolidone coatings on gold nanoparticles and effects on colloidal stability

July 28, 2017

Author(s)

Stacey M. Louie, Justin Gorham, Jiaojie Tan, Vincent A. Hackley

Polymeric coatings are commonly applied to impart functionality and colloidal stability to engineered nanoparticles. In natural environments, transformations of the coating can modify the particle transport behavior, but the mechanisms and outcomes of

Laser induced fluorescence applied in situ to fiber laser welding of 304L stainless steel for improved sensitivity

July 21, 2017

Author(s)

Brian J. Simonds, Jeffrey W. Sowards, Paul A. Williams

Optical spectral analysis of the laser weld plume is common practice as it is a non-contact, in situ technique. However, the low sensitivity of optical emission spectroscopy limits the available information during 1070 nm wavelength laser welding, which is

The control system for the magnetic suspension comparator system for vacuum-to-air mass dissemination

July 21, 2017

Author(s)

Corey A. Stambaugh

High precision mass comparisons are typically performed such that both masses are measured under nearly identical conditions. However, there are situations where an artefact needs to be calibrated against a standard kept under different conditions. For

Traceable Calibration and Demonstration of a Portable Dynamic Force Transfer Standard

July 18, 2017

Author(s)

Akobuije Chijioke

In general, the dynamic sensitivity of a force transducer depends upon the mechanical system in which it is used. This dependence serves as motivation to develop a dynamic force transfer standard, which can be used to calibrate a working transducer "in

Investigation of pore structure in cobalt chrome additively manufactured parts using X-ray computed tomography and three dimensional image analysis

July 15, 2017

Author(s)

Felix Kim, Edward Garboczi, Shawn P. Moylan, John Slotwinski

Pore structures of additively manufactured metal parts were investigated with X-ray Computed Tomography (XCT). Disks made of a cobalt-chrome alloy were produced using laser-based powder bed fusion (PBF) processes. The additive manufacturing processing

Gravity-based characterization of three-axis MEMS-accelerometers in terms of intrinsic accelerometer parameters

July 13, 2017

Author(s)

Jon C. Geist, Muhammad Y. Afridi, Craig McGray, Michael Gaitan

Cross-sensitivity matrices are used to translate the response of three-axis accelerometers into components of acceleration along the axes of a specified coordinate system. For inertial three-axis accelerometers, this coordinate system is often defined by

Calibration of night vision goggles: an SI-units-based measurement technique

July 11, 2017

Author(s)

Vyacheslav B. Podobedov, George P. Eppeldauer, Thomas C. Larason

A new night vision goggles (NVG) gain definition for the calibration process is proposed and evaluated. This definition is based on the radiance measurements at the input and output of the NVG. In contrast to the old definition which uses a non-

Measurements of Mode I Interlaminar Properties of Carbon Fiber Reinforced Polymers using Digital Image Correlation

July 3, 2017

Author(s)

Matthias J. Merzkirch, Louise A. Ahure Powell, Timothy J. Foecke

Numerical models based on cohesive zones are usually used to model and simulate the mechanical behavior of laminated carbon fiber reinforced polymers (CFRP) in automotive and aerospace applications. The codes of these models require different interlaminar

Tip on Tip Imaging and Self-Consistent Calibration using Critical Dimension Atomic Force Microscopy

June 30, 2017

Author(s)

Ronald G. Dixson

Critical dimension atomic force microscopy (CD-AFM) is a measurement technique that uses flared tips and two-dimensional surface sensing to enable scanning of features with near-vertical sidewalls. A major source of uncertainty in metrology with CD-AFM is

Multiple-Instrument Evaluation of the Consistency and Long Term Stability of Tip Width Calibration for Critical Dimension Atomic Force Microscopy

June 19, 2017

Author(s)

Ronald G. Dixson, Ndubuisi G. Orji

Since 2004 standards for calibration of CD-AFM tip width have been available both commercially and through national metrology institutes (NMIs) such as the National Institute of Standards and Technology (NIST) in the United States. There have been inter

Calibration of spectral responsivity of IR detectors in the range from 0.6 mm to 24 mm

June 15, 2017

Author(s)

Vyacheslav B. Podobedov, George P. Eppeldauer, Leonard M. Hanssen, Thomas C. Larason

We report the upgraded performance of the National Institute of Standards and Technology (NIST) facility for spectral responsivity calibrations of infrared (IR) detectors in both radiant power and irradiance measurement modes. The extension of the

Multimodal Characterization of the Morphology and Functional Interfaces in Composite Electrodes for Li-S Batteries by Li Ion and Electron Beams

June 15, 2017

Author(s)

Vladimir P. Oleshko

We report the characterization of multiscale 3D structural architectures of novel poly[sulfur- random-(1,3-diisopropenylbenzene)] copolymer-based cathodes for high-energy-density Li−S batteries capable of realizing discharge capacities >1000 mAh/g and long

Preparation of a Set of Total RNA Benchmarking Samples for Performance Assessment of Genome-scale Differential Gene Expression

June 15, 2017

Author(s)

Lindsay Harris, Patrick S. Pine, Sarah A. Munro, Marc L. Salit

Progress on Single Photon Detector Efficiency Calibrations at NIST

June 14, 2017

Author(s)

Thomas Gerrits, John H. Lehman, Alan Migdall, Sae Woo Nam, Igor Vayshenker, Chih-Ming Wang

We report on our progress towards implementing a measurement service aimed at the calibration of single-photon detectors. We present how our calibration is tied to the calibration of our transfer standard optical fiber power meters. We also developed and

A Method for Improving High-Insertion-Loss Measurements with a Vector Network Analyzer

June 8, 2017

Author(s)

Jeffrey Jargon, Dylan Williams

We present a method for improving high-insertion-loss measurements with a calibrated vector network analyzer (VNA) requiring only two additional pieces of hardware. By utilizing an amplifier and an attenuator, and measuring wave-parameters rather than

Optical microscope illumination analysis using through-focus scanning optical microscopy

June 8, 2017

Author(s)

Ravikiran Attota, Haesung Park

Software Tools for Uncertainty Evaluation in VNA Measurements: A Comparative Study

June 8, 2017

Author(s)

Gustavo Avolio, Dylan Williams, Michael Frey, Sarah B. Streett, Dominique Schreurs, Andrea Ferrero, Michael Dieudonne

We compared three software tools designed for scattering-parameter measurement uncertainty evaluation. These tools propagate uncertainty to calibrated S-parameters by means of a sensitivity analysis. We also validated the sensitivity analysis with Monte

Microparticle tracking velocimetry as a tool for microfluidic flow measurements

June 7, 2017

Author(s)

Paul NMN Salipante, Steven D Hudson, James W. Schmidt, John D. Wright

The accurate measurement of flows in microfluidic channels is important for commercial and research applications. We compare the accuracy of flow measurement techniques over a wide range flows. Flow measurements made using holographic microparticle

Identification of machine tool geometric performance using on-machine inertial measurements

June 6, 2017

Author(s)

Gregory W. Vogl, Radu Pavel, Andreas Archenti, Thomas J. Winnard, Matlock M. Mennu, Brian A. Weiss, Alkan Donmez

Machine tools degrade during operations, yet accurately detecting degradation of machine components such as linear axes is typically a manual and time-consuming process. Thus, manufacturers need automated and efficient methods to diagnose the condition of

Chamber for Mechanical Testing in H2 with Observation by Neutron Scattering

June 1, 2017

Author(s)

Matthew J. Connolly, Peter E. Bradley, Andrew J. Slifka, Elizabeth S. Drexler

A gas-pressure chamber has been designed, constructed, and tested at a moderate pressure (3.4 MPa, 500 psi) and has the capability of mechanical loading of steel specimens for neutron scattering measurements. The chamber will allow a variety of in situ

THE NIST MAGNETIC SUSPENSION MASS COMPARATOR: A LOOK AT TYPE B UNCERTAINTY

May 31, 2017

Author(s)

Corey A. Stambaugh

The magnetic suspension mass comparator is a unique system for calibrating kilogram artifacts between vacuum and air. While the MSMC allows for direct vacuum-to-air mass measurements, there are several corrections that need to be accounted. Here, we

ANALYSYS AND PROTOCOL FOR CHARACTERIZING INTRINSIC PROPERTIES OF THREE-AXIS MEMS ACCELEROMETERS USING A GIMBAL ROTATED IN THE GRAVITATIONAL FIELD

May 30, 2017

Author(s)

Michael Gaitan, Muhammad Y. Afridi, Jon C. Geist

Three-axis MEMS accelerometers are typically characterized in terms of their cross-sensitivity matrix. We present an analysis and protocol to characterize them in terms of their intrinsic properties, which we define as the responsivity of each

Electric field metrology for SI traceability: Systematic measurement uncertainties in electromagnetically induced transparency in atomic vapor

May 24, 2017

Author(s)

Christopher L. Holloway, Matthew T. Simons, Joshua A. Gordon, Georg Raithel, dave Anderson

We investigate the relationship between the Rabi frequency ($\Ω_{RF}$, related to the applied electric field) and Autler-Townes (AT) splitting, when performing atom-based radio- frequency (RF) electric (E) field strength measurements using Rydberg states