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Search Publications by: Robert A. Fletcher (Fed)

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Displaying 1 - 25 of 49

Rapid chemical screening of microplastics and nanoplastics by thermal desorption and pyrolysis mass spectrometry with unsupervised fuzzy clustering

August 11, 2023
Author(s)
Thomas P. Forbes, John Pettibone, Eric S. Windsor, Joseph M. Conny, Robert A. Fletcher
The transport and chemical identification of microplastics and nanoplastics (MNPs) are critical to the concerns over plastic accumulation in the environment. Chemically and physically transient MNP species present unique challenges for isolation and

A Standards and Measurement Infrastructure for Calibration, Verification and Optimization of Trace Explosives Detection Systems

April 15, 2019
Author(s)
John G. Gillen, Jennifer R. Verkouteren, R M. Verkouteren, Marcela N. Najarro, Edward R. Sisco, Matthew E. Staymates, Jessica L. Staymates, Robert A. Fletcher, Jeffrey A. Lawrence, Elizabeth L. Robinson, Alexander T. Bulk, Joseph A. Bennett, Shinichiro Muramoto, Thomas P. Forbes
Current national priorities in homeland security have led to an unprecedented level of utilization of explosives trace detection (ETD) systems for counterterrorism and law enforcement. Despite the widespread deployment of ETD instruments at airports

Characterization of Chemical Properties, Unit Cell Parameters and Particle Size Distribution of Three Zeolite Reference Materials: RM 8850 - Zeolite Y, RM 8851 - Linde Type A Zeolite and RM 8852 - Ammonium ZSM-5 Zeolite

April 4, 2017
Author(s)
Shirley Turner, Robert A. Fletcher, Eric S. Windsor, Jennifer R. Verkouteren, John R. Sieber, Thomas W. Vetter, Rolf L. Zeisler, Anthony F. Marlow, M E. Davis, G J. Kennedy, W S. Borghard, S Yang, A Navrotsky, B H. Toby, James F. Kelly, Stefan D. Leigh
Zeolites have important industrial applications including use as catalysts, molecular sieves and ion exchange materials. In this study, three zeolite materials have been characterized by the National Institute of Standards and Technology (NIST) as

Certification of New Standard Reference Material 2806b Medium Test Dust in Hydraulic Oil

December 19, 2016
Author(s)
Robert A. Fletcher, Nicholas W. Ritchie, David S. Bright, James J. Filliben, William F. Guthrie
A new material has been certified to become Standard Reference Material (SRM) 2806b - Medium Test Dust in Hydraulic Fluid. SRM 2806b consists of a trace polydisperse, irregularly shaped mineral dust particles suspended in hydraulic fluid. The certified

Electrostatic Microprobe for Determining Charge Domains on Surfaces

November 2, 2015
Author(s)
Robert A. Fletcher
The electrostatic microprobe is a laboratory constructed instrument with the design purpose to measure charge content on wipe and various control surfaces. The device is constructed on an optical microscope platform, with a computer automated XY stage

Quantifying Trace 2,4,6-Trinitrotoluene (TNT) in Polymer Microspheres

October 16, 2015
Author(s)
Timothy M. Brewer, Robert A. Fletcher, Matthew E. Staymates
Well characterized test materials are essential for validating the performance of current trace explosive detection systems. Explosive encapsulated microspheres have proven to be a valuable test material for trace explosive detection because their precise

Chapter 21 Calibration of Aerosol Instruments

July 5, 2011
Author(s)
Bean T. Chen, Robert A. Fletcher, Yung-Sung Cheng
This chapter reviews calibration techniques relevant to aerosol measurement devices, such as sizing instruments, condensation nuclei counters, and mass monitors. The generation methods for test aerosols and important parameters in instrument calibration

Microscopy and Microanalysis of Individual Collected Particles- Chapter 10

July 5, 2011
Author(s)
Robert A. Fletcher, Nicholas W. Ritchie, Ian M. Anderson, John A. Small
This chapter describes microscopy and microanalysis techniques used for the characterization of collected, individual particles in a variety of instruments. The instruments discussed are the light microscope, electron microscopes (both scanning and

Application of Inkjet Printing Technology to Produce Test Materials of 1,3,5-Trinitro-1,3,5 Triazcyclohexane for Trace Explosive Analysis

October 15, 2010
Author(s)
Eric S. Windsor, Marcela N. Najarro, Anna N. Bloom, Bruce A. Benner Jr, Robert A. Fletcher, John G. Gillen, Richard Lareau, Inho Cho, Mike Boldmand
The feasibility of using piezoelectric drop-on-demand inkjet printing to prepare test materials for trace explosive analysis is demonstrated. Both pure high explosives and plastic-bonded putty explosives were formulated into inkjet printable solutions and

Production and Characterization of Polymer Microspheres Containing Trace Explosives Using Precision Particle Fabrication Technology

August 2, 2010
Author(s)
Matthew E. Staymates, Robert A. Fletcher, Jessica L. Staymates, John G. Gillen, Cory Berkland
Well characterized test materials are essential for validating the performance of current trace explosive detection systems. These test materials must replicate trace explosive contamination in the form of small particles with characteristic diameters in

Flow Visualization Techniques for the Evaluation of Non-Contact Trace Contraband Detectors

August 1, 2010
Author(s)
Matthew E. Staymates, Wayne Smith, John G. Gillen, Richard T. Lareau, Robert A. Fletcher
Efforts are underway in the Surface and Microanalysis Science Division at the National Institute of Standards and Technology to study trace aerodynamic sampling of explosive particles using walk-through portal-based detection systems. Explosive trace

Data Mining Electron Microscope Images to Estimate a Particle Size Distribution

October 16, 2008
Author(s)
Walter S. Liggett Jr, Robert A. Fletcher
The application considered involves density estimation, spatial prediction, and sizing error. The goal is estimation of a particle size distribution; the data are scanning electron microscope (SEM) images that constitute a sample of a filter surface; and

Metrology in Support of Trace Explosive Detection Equipment for Airport Security Applications.

October 16, 2008
Author(s)
George A. Klouda, J Greg Gillen, Robert A. Fletcher, E S. Etz, Jennifer R. Verkouteren, R. Michael Verkouteren, E Ferguson
We are working in collaboration with the Transportation Security Agency's Trace Explosive Detection Group to build a chemical metrology program to help support the widespread operational deployment and effective utilization of trace explosives detection

Trace Explosive Detection Standards Using Drop-on-Demand Inkjet Printing Technology

October 16, 2008
Author(s)
Eric S. Windsor, Bruce A. Benner Jr., Robert A. Fletcher, J Greg Gillen, R Lareau, Inho Cho, Mike Boldmand
A piezoelectric drop-on-demand inkjet printer system has been used to prepare prototype trace explosive calibration materials to aid in the performance evaluation of ion mobility spectrometry instruments that are now widely deployed in support of homeland

Method to Determine Collection Efficiency of Particles by Swipe Sampling

September 1, 2008
Author(s)
Jennifer R. Verkouteren, Jessica L. Staymates, Robert A. Fletcher, Wayne Smith, George A. Klouda, John G. Gillen
A methodology was developed to evaluate particle collection efficiencies from swipe sampling of trace residues. Swipe sampling is used for many applications where trace residues must be collected, including the evaluation of radioactive particle

NIST Program to Support Testing and Evaluation of Trace Explosive Detection

October 1, 2007
Author(s)
R M. Verkouteren, John G. Gillen, Jennifer R. Verkouteren, Robert A. Fletcher, Eric S. Windsor, Wayne Smith
Trace detection is a primary strategy for thwarting terrorism activities in the US and abroad. The development of effective reference materials and methods for this purpose relies on fundamental knowledge regarding the size, mass, morphologies, and

Inkjet Metrology and Standards for Ion Mobility Spectrometry

September 1, 2007
Author(s)
R M. Verkouteren, J Brazin, Eric S. Windsor, Robert A. Fletcher, R Maditz, Wayne Smith, John G. Gillen
Piezoelectric inkjet nozzles offer precise control for dispensing small quantities of materials. NIST is developing inkjet metrology to provide reference materials, calibration services, and other standards for the IMS detection of trace contraband