v. 1.0, 3/15/10, Howington 1 Purpose: Improve understanding of the processes controlling threat detection by chemical sensors in complex surface and subsurface environments Product/Results: Identification of critical processes through unique combination of column-scale laboratory experiments and low-speed wind tunnel with homogeneous, heterogeneous soils, targets, and atmospheric controls (FY11/12) Improved model parameterization of mass, momentum, and energy transfer across the soil/air interface (FY13) Chemical sensing computational testbed (FY13) Payoff: Smarter deployment and design of chemical sensors Improved detection of buried and concealed threats Improved understanding and modeling capability at the critical soil/air interface will benefit this and other sensing modalities (infrared and radar) and our hydrology and remote sensing business areas Improved simulation tools (in particular, air flow, two-phase flow and transport in soil) can be used across civil works and military support programs Schedule & Cost Total $640K MILESTONES FY11 FY12 FY13 Army ($K) Laboratory experiments in CSM soil and windtunnel Improved Characterization of Chemical Sensing in Complex Surface and Subsurface Environments Chemical sensing computational testbed WP # Status: New Mini mass spectrometer Laboratory experiments in large ERDC columns

v. 1.0, 3/15/10, Howington 2 Purpose: Improve understanding of the processes controlling threat detection by chemical sensors in complex surface and subsurface environments Product/Results: Identification of critical processes through unique combination of column-scale laboratory experiments and low-speed wind tunnel with homogeneous, heterogeneous soils, targets, and atmospheric controls (FY11/12) High-fidelity simulation capability for chemical signals in near-surface environments (FY13) Improved model parameterization of mass, momentum, and energy transfer across the soil/air interface (FY13) (MWF drop this?) Payoff: Smarter deployment and design of chemical sensors Improved detection of buried and concealed threats Improved understanding and modeling capability at the critical soil/air interface will benefit this and other sensing modalities (infrared and radar) and our hydrology and remote sensing business areas Improved simulation tools (in particular, air flow, two-phase flow and transport in soil) can be used across civil works and military support programs Schedule & Cost Total $640K MILESTONES FY11 FY12 FY13 Army ($K) Laboratory experiments in CSM soil and windtunnel Improved Characterization of Chemical Sensing in Complex Surface and Subsurface Environments High-resolution computational framework WP # Status: New Mini mass spectrometer Laboratory experiments in large ERDC columns

v. 1.0, 3/15/10, Howington 3 1. What is the problem? The DoD, DHS, and others rely increasingly on sensors to detect threats ranging from explosive devices (e.g., landmines, bombs, and IEDs) to chemical and biological agents. Performance of chemical sensors to detect shallow buried targets depends strongly on the local conditions and the sampling strategy. 2. What are the barriers to solving the problem? There are experimental and computational challenges ahead. We do not yet understand the relative importance of the transport processes from the target to the sensor. Isolating and exploring these processes is impossible in a field setting and difficult in the laboratory. Likewise, while individual modeling tools exist, none can yet predict the transport of reactive chemicals through the shallow subsurface and into the near-ground boundary layer. 3. How will you overcome these barriers? The testable hypothesis is that the deployment and future design of chemical sensors can be improved substantially by developing a quantitative, process understanding and numerical simulation capability as a function of soil-atmospheric fluid dynamics, soil structure, soil composition, and geochemistry. The technical approach/research plan involves three components (1.) high fidelity experimentation, (2.) cutting-edge simulation, and (3.) extraction of operational and design guidance. 4. What are the anticipated results and value of this research? We will develop a laboratory dataset of sufficient quality to permit process description and numerical model construction. construct a suite of validated computational tools for high-resolution, realistic simulation of the physical and chemical processes relevant for detecting threats using air sampling (sniffing). This advanced simulation capability will help refine sensor design and establish operational guidance, thus expanding DoD's toolbox for threat detection with an important class of sensors. 5. What is innovative about this work? The experimental program is unprecedented in both fidelity and process control. The facility at CSM is unique and ideally suited for this problem. ERDC has developed several component computational tools but their extension to solve this problem and their coupling at the air-soil interface at these time and space scales have not been done previously. 6. What is your publication plan? Characterizing the impact of atmospheric conditions on vapor transport in the near-surface, Water Resources Research Coupled, high-resolution simulations of near-surface flow and transport phenomena, Computer Methods in Applied Mechanics and Engineering or Advances in Water Resources Assessing the impact of near-surface and subsurface conditions on chemical signals from buried targets.Journal of Environmental Quality 7. Transition plan: Improved understanding and modeling capability at the critical soil/air interface will benefit this and other sensing modalities (infrared and radar) and our hydrology and remote sensing business areas Improved simulation tools (in particular, air flow, two-phase flow and transport in soil) can be used across civil works and military support programs to assess chemical and biological threats These tools can be transitioned to other DoD labs in much the same way as the Countermine tools are being adopted by the Night Vision and Electronic Sensors Directorate 8. Collaboration across ERDC, commercial firms and/or academia: The multi-laboratory GEOTACS team for remote sensing of threats Researchers in the ERDC Environmental Laboratory who have significant experience in both the transport of explosives and chemical detection The Night Vision and Electronic Sensors Directorate is partnering with ERDC to improve the general understanding of sensor performance in the environment. Other participants include Professor Illangasekare’s experimental team at the Colorado School of Mines Improved Characterization of Chemical Sensing in Complex Surface and Subsurface Environments WP # Status: New

v. 1.0, 3/15/10, Howington 4 Improved Characterization of Chemical Sensing in Complex Surface and Subsurface Environments WP # Status: New Q1. What is the research problem? Chemical sensors cannot be deployed or designed effectively without accounting for the effects of the complex, cluttered, dynamic environments in which they are used. Q2. Describe the research objective. This effort will advance understanding of the processes controlling the migration of chemical signals from buried targets to above-ground sensors. Q3. What is the toughest technical challenge in the work? We must identify and quantify the dominant processes in the migration of explosives chemicals from shallow buried targets to airborne sensors. The toughest challenge in computation will be in accurately describing the dynamics of moisture, energy, and chemical exchange between the ground and air. Q4. If successful, what will be the significance and impact of this research? This work will lead to improved tactics for chemical sensor use, improved sensor design, and, potentially, techniques for local environmental modification to enhance detection. Q5. What future applications could result from this research? Our improved knowledge of the physical and chemical processes at work in the near-surface will improve our phenomenological understanding across the spectrum of threat sensing. In particular, the air flow modeling would be useful to explore airborne threats from terrorist acts. Q6. What other organizations are pursuing this research? Our partners at the Night Vision and Electronic Sensors Directorate are collaborating with ERDC on similar efforts. Others, like the Defense Science and Technology Laboratory in the United Kingdom, are pursuing computational tools of the same general purpose, but at lower fidelity. Q7. What makes this research innovative, original and high risk? The experiments and computations proposed are novel in their scope and fidelity. This effort is high risk because guidance for field use of chemical sensors may only be possible with impractical types or quantities of local, supporting data. Q8. How could this research develop future capabilities for ERDC? Chemical detectors have direct military application in theaters of operation for detecting (primarily) explosives, but also have many homeland defense uses. For example, sniffers can help ensure the safety of agents exploring cross-border tunnels, and may aid in the detection of bombs in vehicles, subway tunnels, etc. By expanding our sensor simulation and design toolbox to include chemical detectors, ERDC will advance its position as a technology leader in anti-terrorism and operational military support. Customers likely will include the intelligence agencies, DARPA, and several DoD offices. Q9. Describe the research team and plan. The research team includes seasoned experimentalists and computational experts ranging from fluid flow, porous media, and geochemistry. Q10. Is there adequate funding, equipment, and facilities to complete this research as planned? Because the experimental facilities and some computational parts exist, the funding and facilities should be adequate to perform this work.

v. 1.0, 3/15/10, Howington 5 Task I: Experimental investigation of mass and energy transport through the shallow subsurface to the soil- air boundary under temporally varying, but spatially distributed atmospheric forcing Outline: Large column experimental systems at ERDC focusing on the impact of atmospheric forcing and (layered) subsurface heterogeneity on soil moisture distribution and the accessibility of transport pathways (aqueous or gas phase) to buried sources. We will begin with conservative and semi-volatile surrogates, which ideally will provide bounds for the behavior of explosives-related compounds in terms of access to available transport pathways. We will test this hypothesis by repeating the column experiments with RDX compounds Experimental Plan Improved Characterization of Chemical Sensing in Complex Surface and Subsurface Environments WP # Status: New

v. 1.0, 3/15/10, Howington 6 Task II: Experimental investigation of the coupling of near- surface boundary layer dynamics with mass, energy, and momentum transport through the shallow subsurface Outline: Extend initial column-scale experiments to allow for more complex atmospheric coupling and significant (potential) lateral transport State-of-the-art, low velocity wind tunnel at CSM allows control of wind speed, temperature, humidity, thermal loading, and precipitation along with large, highly instrumented soil tanks. Upgrading existing ERDC facilities with these capabilities is cost- prohibitive with a 6.1 budget Experimental Plan Improved Characterization of Chemical Sensing in Complex Surface and Subsurface Environments WP # Status: New Wind Tunnel Experimental Facility

v. 1.0, 3/15/10, Howington 7 Task III: Extension and validation of simulation tools for flow and transport in near-surface and subsurface environments Outline: Existing computational platform for large-scale multiphase, multiphysics simulations underlying countermine test bed (CTB). Resolving trace concentration levels through the vadose zone into complex air flows in the near- surface boundary layer is a significant, new challenge High-accuracy Eulerian-Lagrangian methods for constituent transport Improved variational multiscale methods for 2- phase Darcy flow Isogeometric, variational multiscale methods for incompressible Navier-Stokes through vegetation Accurate coupling of Navier-Stokes and Darcy flow regions Improved Characterization of Chemical Sensing in Complex Surface and Subsurface Environments WP # Status: New Temperature contours through soil and vegetation for typical countermine simulation(MWF: need details)