Matthew Staymates

National Institute of Standards and Technology (NIST)

Novel Investigations in Trace Explosives Collection

Overview

• Cargo sampling at Penn State

• Trace sampling and detection

• Metrology tools for sampling– Schlieren imaging

– High speed videography

– Flow visualization

• ETD System Characterization– Vortex sampler

– Shoe sampler

• Biomimicry / Canine Olfaction

• Standards and test materials

Penn State Gas Dynamics Lab

• Sea-cargo container characterization

• Scale model construction

• Computational Fluid Dynamics

• Experimental flow visualization

• Explosive trace detection experiments

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“Internal Aerodynamics and Explosive Trace Sampling of Sea-Cargo Containers”

Cargo Container Flow Visualization

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What happens when you withdraw air from one vent?

40% scale model

Computational model

Cargo Container Flow Visualization – CFD results

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• 0.5-21” H2O• Conclusion: No

significant changes in aerodynamic flow patterns– Visualized by

contours of wall shear stress

– Increase in wall shear stress with suction pressure (as expected)

Cargo Container Flow Visualization

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• Modeled 90%-full cargo container

• Used 1 Hp blower as air mover

• Theatrical fog (smoke) and laser light sheet illumination

• Suction pressure of 3” H20

Cargo Container Flow Visualization

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Cargo Container Flow Visualization

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Explosive Sampling Experiments

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Particle impactor

• Cartridge heater used as particle generator– 5 µg of RDX for each experiment

• Metal-mesh tab on impactor surface

• Procedure:– Reach steady state conditions

– Vapor release

– Sample for 2 minutes

– Analysis into Itemiser3

• All locations repeated 3 times

• Test for contamination after each run

Explosive Sampling Results

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• All locations were detectable

• Signal strength is a function of location from suction vent– May be due to deposition on surfaces

Suggestions and Conclusions

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• Apply pressure to create inlet jet, then reverse the flow

• If possible, sample from both vents

• Three potential designs (Backpack mounted, Truck mounted, Stationary)

• Typical sea-cargo container is 40 feet in length, 90%-full by volume, with two vents

• Two distinct flow patterns emerge when suction is applied to one vent

-Inlet jet/vortex, Should be considered a tool to liberate particles

• Experiments show signal strength is a function of location inside container

-Suggests a logical sampling strategy

Many thanks to Gary Settles, PSU Gas Dynamics Lab

NIST Trace Detection Program

Detection System Performance

Standard Test Materials

What is being sampled?Sampling Optimization

Operational Improvements / Training

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Acknowledgements• Our group at NIST includes:

– Greg Gillen, Jessica Staymates, Matt Staymates, Jennifer Verkouteren, Robert Fletcher, Mike Verkouteren, Marcela Najarro, Tim Brewer, Eric Windsor, Tom Forbes, George Klouda, Jeff Lawrence, Shin Muramoto, Edward Sisco

The Science and Technology Directorate of the U.S. Department of Homeland Security sponsored the production of this work under an Interagency Agreement

with the National Institute of Standards and Technology.

Certain commercial equipment, instruments, or materials are identified in this document. Such identification does not imply

recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the products

identified are necessarily the best available for the purpose.

SummaryOver the last several years NIST has developed a unique suite of metrology tools and acquired the experience necessary to address the measurement and standards issues

in the application of trace contraband detection.