U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by: N. Alan Heckert (Fed)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 51 - 75 of 186

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 ( 4 mm and 10 mm) for the Determination of Organic and Inorganic Constituents

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 ( 4 µm) and SRM 2787 Fine Particulate Matter ( 10 µm) have been developed in support of the US Environmental Protection Agency's National Ambient Air Quality Standards for

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