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Search Publications by: N. Alan Heckert (Fed)

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Displaying 26 - 50 of 94

UNCERTAINTY IN MULTI-SCALE CREEP RUPTURE LIFE MODELING AND A NEW APPROACH TO ESTIMATING FREQUENCY OF IN-SERVICE INSPECTION OF COMPONENTS AT ELEVATED TEMPERATURES (*)

April 3, 2018
Author(s)
Jeffrey T. Fong, Nathanael A. Heckert, James J. Filliben, Marvin J. Cohn
Uncertainty in modeling the creep rupture life of a full-scale component using experimental data at microscopic (Level 1), specimen (Level 2), and full-size (Level 3) scales, is addressed by applying statistical theory of prediction intervals, and that of

Development of Orthogonal NISTmAb Size Heterogeneity Control Methods

February 10, 2018
Author(s)
Abigail Turner, Katharina S. Yandrofski, Srivalli Telikepalli, N. Alan Heckert, James J. Filliben, Dean C. Ripple, John E. Schiel
The NISTmAb is an innovative monoclonal antibody reference material from the National Institute of Standards and Technology; it is a class-representative IgG1κ intended to serve as a pre-competitive platform for harmonization and technology development in

LipidQC: Method Validation Tool for Visual Comparison to SRM 1950 Using NIST Interlaboratory Comparison Exercise Lipid Consensus Mean Estimate Values

November 17, 2017
Author(s)
Candice Z. Ulmer, Jared Ragland, Jeremy P. Koelmel, N. Alan Heckert, Christina Jones, Timothy J. Garrett, Richard A. Yost, John Bowden
As advances in analytical separation techniques, mass spectrometry instrumentation, and data processing platforms continue to spur growth in the lipidomics field, more structurally unique lipid species are detected and annotated. The lipidomics community

MRI Birdcage RF Coil Resonance with Uncertainty and Relative Error Convergence Rates

October 4, 2017
Author(s)
Jeffrey T. Fong, Nathanael A. Heckert, James J. Filliben, Pedro V. Marcal, Robert Rainsberger, Karl F. Stupic, Stephen E. Russek
In a magnetic resonance imaging (MRI) system, it is necessary to excite the nuclei of a patient into coherent precession for imaging. This requires a coupling between the nuclei and a source of radio frequency (RF) power using a transmitter. To receive a

Using Design of Experiments in Finite Element Modeling to Identify Critical Variables in Laser Powder Bed Fusion

August 11, 2016
Author(s)
Li Ma, Jeffrey T. Fong, Brandon Lane, Shawn P. Moylan, James J. Filliben, N. Alan Heckert, Lyle E. Levine
In Laser Powder Bed Fusion (L-PBF) Finite Element Analysis (FEA), input of accurate material and simulation parameters is critical for accurate predictions. It is challenging and expensive to measure and control all possible material properties and process

A STATISTICAL APPROACH TO ESTIMATING A 95 % CONFIDENCE LOWER LIMIT FOR THE DESIGN CREEP RUPTURE TIME VS. STRESS CURVE WHEN THE STRESS ESTIMATE HAS AN ERROR UP TO 2 % (*)

July 17, 2016
Author(s)
Jeffrey T. Fong, James J. Filliben, Nathanael A. Heckert, Pedro V. Marcal, Marvin J. Cohn
Recent experimental results on creep-fracture damage with minimum time to failure (minTTF) varying as the 9th power of stress, and a theoretical consequence that the coefficient of variation (CV) of minTTF is necessarily 9 times that of the CV of the

Development of Two Fine Particulate Matter Standard Reference Materials (

April 13, 2016
Author(s)
Michele M. Schantz, Danielle Cleveland, N. Alan Heckert, John Kucklick, Stefan D. Leigh, Stephen E. Long, Jennifer Lynch, Karen E. Murphy, Rabia Oflaz, Adam L. Pintar, Barbara J. Porter, Savelas A. Rabb, Stacy Schuur, Stephen Wise, Rolf L. Zeisler
Two new Standard Reference Materials (SRMs), SRM 2786 Fine Particulate Matter (

Uncertainty Quantification of Stresses in a Cracked Pipe Elbow Weldment Using a Logistic Function Fit, a Nonlinear Least Squares Algorithm, and a Super-Parametric Method

December 30, 2015
Author(s)
Jeffrey T. Fong, James J. Filliben, Nathanael A. Heckert, Pedro V. Marcal, Robert Rainsberger, Li Ma
In a 3-part series of papers, of which this paper is Part II, we investigate the applicability of the fully quadratic hexa-27 element (see Part I) to four problems of interest to the pressure vessels and piping community: (1) The solid-element-based

The Occurrence of Repeated Fiber Breaks in Microcomposites

November 10, 2015
Author(s)
Gale A. Holmes, Edward D. McCarthy, Nathanael A. Heckert, Stefan D. Leigh, Jae Hyun Kim, Jeffrey W. Gilman
The mechanical integrity of a structural composite is strongly affected by the strength and toughness of the fiber–matrix interface/interphase (Norwood, 1994), with interfacial shear strength (IFSS) considered the best quantifying metric. IFSS outputs are

The Fiber Break Evolution Process in a 2-D Epoxy/Glass Multi-Fiber Array

November 2, 2015
Author(s)
Edward D. McCarthy, Jae H. Kim, N. Alan Heckert, Stefan D. Leigh, Jeffrey W. Gilman, Gale A. Holmes
The mechanical integrity of a structural composite is strongly affected by the strength and toughness of the fiber-matrix interface/interphase [1], with interfacial shear strength (IFSS) being the accepted quanti-fying metric. However, the value of the

Multi-scale measurement for tensile behaviors of glass fiber composites at high rate loading: Fiber fragmentation behaviors in epoxy resin

May 19, 2015
Author(s)
Jae Hyun Kim, Steven P. Mates, Nathanael A. Heckert, Walter G. McDonough, Gale A. Holmes
High strength and light weight composite materials used in various structural components of aviation and automotive applications deform under high rate loading conditions during collision. Since composite structures using continuous fibers are constituted

Development of Urine Standard Reference Materials for Metabolites of Organic Chemicals Including Polycyclic Aromatic Hydrocarbons, Phthalates, Phenols, Parabens, and Volatile Organic Compounds

April 1, 2015
Author(s)
Michele M. Schantz, Bruce A. Benner Jr., Nathanael A. Heckert, Lane C. Sander, Katherine E. Sharpless, Stacy S. Schuur, Stephen A. Wise
Two new Standard Reference Materials (SRMs), SRM 3672 Organic Contaminants in Smokers’ Urine (Frozen) and SRM 3673 Organic Contaminants in Non-Smokers’ Urine (Frozen), have been developed in support of studies for assessment of human exposure to select

The Testing Program at NIST on Fibers Used in Soft Body Armor Applications

March 21, 2015
Author(s)
Walter G. McDonough, Amanda L. Forster, Jae Hyun Kim, Nathanael A. Heckert, Joy P. Dunkers, Scott A. Wight, Gale A. Holmes
The goal of this paper and presentation is to give an update of the research effort to date being conducted at the National Institute of Standards and Technology (NIST) on polymeric fibers used in soft body armor with a special emphasis on new fibers under

A Design-of-Experiments Approach to FEM Uncertainty Analysis for Optimizing Magnetic Resonance Imaging RF Coil Design

October 10, 2014
Author(s)
Jeffrey T. Fong, Nathanael A. Heckert, James J. Filliben, Li Ma, Karl F. Stupic, Kathryn E. Keenan, Stephen E. Russek
Using the RF module of COMSOL, we compute the magnetic flux density norm (BN) profiles for frequencies in the 76 to 100 MHz range, inside of a prototype birdcage coil, courtesy of Japan's National Institute of Radiological Sciences (NIRS), loaded with a