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Search Publications by: N. Alan Heckert (Fed)

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Displaying 51 - 75 of 95

Analyzing a Co-Polymer Aramid Fiber for Use in Soft Body Armor

October 25, 2013
Author(s)
Walter G. McDonough, Jae Hyun Kim, Nathanael A. Heckert, Amanda L. Forster, Scott A. Wight, Joy P. Dunkers, Gale A. Holmes
Since the well-publicized failure of body armor used by a police officer, it has become imperative that the long-term properties and performance of new fibers being considered for use be understood. The range of interest is from the molecular properties of

Statistical Analysis of Single PPTA Fibers

August 2, 2013
Author(s)
Nathanael A. Heckert
Discuss statistical methods used for analysis of single fiber tensile strength tests. Kernel density plots and quantile-quantile plots were used to graphically analyze the data. Fiber strength was modeled using 2-parameter Weibull, 3-parameter Weibull

Statistical Analysis of Single PPTA Fibers

July 28, 2013
Author(s)
N. Alan Heckert, Jae H. Kim, Kirk D. Rice, Gale A. Holmes
Discuss statistical methods used for analysis of single fiber tensile strength tests. Kernel density plots and quantile-quantile plots were used to graphically analyze the data. Fiber strength was modeled using 2-parameter Weibull, 3-parameter Weibull

Toward the Development of a High Strain Rate Testing Standard for Advanced Fibers

May 24, 2013
Author(s)
Gale A. Holmes, Jae Hyun Kim, Nathanael A. Heckert, Walter G. McDonough, Stefan D. Leigh, Kirk D. Rice
The use of advanced fibers in applications where they are subjected to extremely energetic events has necessitated the need to develop measurement tools that quantify their properties at high strain rates (HSR). The split Hopkinson tension bar (SHTB) has

An Interlaboratory Investigation of the Effect of Material Granularity and Sample Processing on Measurement Variability: Nutritional Elements in Cereals

May 9, 2013
Author(s)
Katrice A. Lippa, Laura J. Wood, Stefan D. Leigh, Nathanael A. Heckert
This interlaboratory study was uniquely designed to determine the effects of material granularity and sample processing techniques on the measurement variability (i.e. precision) of nutritional elements in various cereal materials. Participants were asked

Effects of fiber gripping methods on single fiber tensile tests: Parametric statistical analyses of tensile strengths and failure strains

May 9, 2013
Author(s)
Jae Hyun Kim, Nathanael A. Heckert, Walter G. McDonough, Kirk D. Rice, Gale A. Holmes
The Kolsky bar test has been widely used in measuring material response under high strain rate conditions. Initial experiments in the literature applying this test to measure single fiber properties for fibers used in soft body armor with the Kolsky bar

Effects of fiber gripping methods on the single fiber tensile test: I. Non parametric statistical analysis

February 15, 2013
Author(s)
Jae Hyun Kim, Nathanael A. Heckert, Stefan D. Leigh, Haruki Kobayashi, Walter G. McDonough, Kirk D. Rice, Gale A. Holmes
Single fiber tensile tests using two different gripping methods were carried out on various fiber lengths. One method (the glue-tab grip) consists of mounting a fiber onto a rigid tab as specified in ASTM C1557-03 using an adhesive, while the other (the

Breakfast Cereal Sampling Study for Nutritional Elements

February 5, 2013
Author(s)
Laura J. Wood, Katrice A. Lippa, Melissa M. Phillips, Catherine A. Rimmer, Nathanael A. Heckert, Stefan D. Leigh, Amanda J. Moors, Rebecca S. Pugh
The National Institute of Standards and Technology (NIST) has established a Dietary Supplement Laboratory Quality Assurance Program (DSQAP) in collaboration with the National Institutes of Health Office of Dietary Supplements (NIH-ODS). The DSQAP designed

A Stochastic and Local Theory of Fatigue for Aging Pressure Vessels and Piping

November 4, 2012
Author(s)
Jeffrey T. Fong, Nathanael A. Heckert, James J. Filliben
We begin with a review of the fatigue design methodology for new pressure vessels and piping, based on both deterministic and stochastic approaches. We will then prove that the same methodology for estimating the remaining life of aging pressure vessels

Tensile behavior of single PPTA fibers measured by the Kolsky bar using the direct fiber clamping method

June 11, 2012
Author(s)
Jae Hyun Kim, Nathanael A. Heckert, Stefan D. Leigh, Haruki Kobayashi, Walter G. McDonough, Richard L. Rhorer, Kirk D. Rice, Gale A. Holmes
The Kolsky bar test has been widely used in measuring material behavior under high strain rate conditions. In particular, this methodology has been used to characterize the high strain rate behavior of polymer and polymer composites during ballistic impact