21 Jun 2023

Comparison of the Quantitation of Heavy Metals in Soil Using Handheld LIBS, XRFS, and ICP-OES

Abstract: Handheld laser-induced breakdown spectroscopy (LIBS) is an emerging analytical technique that shows the potential to replace X-ray fluorescence spectroscopy (XRFS) in the field characterization of soils containing heavy metals. This study explored the accuracy and precision of handheld LIBS for analyzing soils containing copper and zinc to support LIBS as a re-placement for XRFS technology in situ. Success was defined by handheld LIBS results that could be replicated across field analyzers and verified by inductively coupled plasma–optical emission spectrometry (ICP-OES). A total of 108 soil samples from eight military installations were pressed into 13 mm pellets and then analyzed by XRFS and LIBS. Handheld LIBS has a spot-size area 100-fold smaller than that of XRFS, and though it provided accurate measurements for NIST-certified reference materials, it was not able to measure unknown soils of varying soil texture with high particle size variability, regardless of sample size. Thus, soil sample particle size heterogeneity hindered the ability to provide accurate results and replicate quantitation results across LIBS and XRFS. Increasing the number of particles encountered by each shot through particle size reduction improved both field-analyzer correlation and the correlation between handheld LIBS and ICP-OES from weak (<15%) to strong (>80%).

2 Jun 2023

A Generalized Photon-Tracking Approach to Simulate Spectral Snow Albedo and Transmittance Using X-ray Microtomography and Geometric Optics

Abstract: A majority of snow radiative transfer models (RTMs) treat snow as a collection of idealized grains rather than an organized ice–air matrix. Here we present a generalized multi-layer photon-tracking RTM that simulates light reflectance and transmittance of snow based on X-ray micro- tomography images, treating snow as a coherent 3D structure rather than a collection of grains. The model uses a blended approach to expand ray-tracing techniques applied to sub-1 cm3 snow samples to snowpacks of arbitrary depths. While this framework has many potential applications, this study’s effort is focused on simulating reflectance and transmittance in the visible and near infrared (NIR) through thin snow- packs as this is relevant for surface energy balance and remote sensing applications. We demonstrate that this framework fits well within the context of previous work and capably reproduces many known optical properties of a snow surface, including the dependence of spectral reflectance on the snow specific surface area and incident zenith angle as well as the surface bidirectional reflectance distribution function (BRDF). To evaluate the model, we compare it against reflectance data collected with a spectroradiometer at a field site in east-central Vermont. In this experiment, painted panels were inserted at various depths beneath the snow to emulate thin snow. The model compares remarkably well against the reflectance measured with a spectroradiometer, with an average RMSE of 0.03 in the 400–1600 nm range. Sensitivity simulations using this model indicate that snow transmittance is greatest in the visible wavelengths, limiting light penetration to the top 6 cm of the snowpack for fine-grain snow but increasing to 12 cm for coarse-grain snow. These results suggest that the 5% transmission depth in snow can vary by over 6 cm according to the snow type.

31 May 2023

Application of a Satellite-Retrieved Sheltering Parameterization (v1.0) for Dust Event Simulation with WRF-Chem v4.1

Abstract: Roughness features (e.g., rocks, vegetation, furrows) that attenuate wind flow over the soil surface can affect the magnitude and distribution of sediment transport in aeolian environments. Existing transport models often rely on vegetation attributes derived from static land use datasets or remotely sensed greenness indicators to incorporate sheltering effects on simulated particle mobilization. These approaches do not represent the 3D nature or spatiotemporal changes of roughness element sheltering and ignore the sheltering contribution of nonvegetation roughness features and brown vegetation common to dryland environments. We used an albedo-based sheltering parameterization in a dust transport modeling application of the Weather Research and Forecasting model with Chemistry (WRF-Chem). This method estimates sheltering effects on surface wind friction speeds and dust entrainment from the shadows cast by subgrid-scale roughness elements. We applied the albedo-derived drag partition to the Air Force Weather Agency (AFWA) dust emission module and studied simulated PM10 concentrations using the Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) model as implemented in WRF-Chem v4.1. Our results demonstrate how dust transport simulation and forecasting with the AFWA dust module can be improved in vegetated drylands by calculating dust emission flux with surface wind friction speed from a drag partition treatment.

24 May 2023

Analysis of Paxton Siphon Frazil Ice Blockage Event during January 2022

Abstract: In early January 2022, the Paxton Siphon, owned and operated by the Nebraska Public Power District, filled with frazil ice creating a blockage that resulted in a rapid upstream stage rise for the Sutherland Canal. An event of this type has never happened in the over 80 years of operating the Paxton Siphon. An analysis of the available weather and canal data suggests a rapid air temperature change resulted in the water becoming supercooled, which combined with the moderately low flows in the canal resulted in an anomalous frazil ice formation event. To address this issue for future cold weather events, a water temperature model was developed using the Hydrologic Engineering Center’s River Analysis System and can be used to determine the spatial extents of the supercooling event using forecasted weather information. In addition, we developed a heat-exchange forecast tool that can be used operationally to screen for potential frazil ice formation periods with a 1-week outlook period.

19 May 2023

Summary of Ice Jams and Mitigation Techniques in Alaska

Abstract: Ice is an important part of the Alaska ecosystems and can form through dynamic (e.g., frazil) or static (e.g., thermal) processes. In Alaska, both freeze-up and breakup ice jams occur, however breakup jams during the spring snowmelt period are most common. Historically there have been many river systems in Alaska that have chronic ice jam issues. These ice jams have resulted in several significant ice jam floods. There are several ice jam mitigation techniques that can be used to either provide state and local emergency managers warnings of a potential ice jam or reduce the impacts of a jam. Common relatively low-cost mitigation methods that can be implemented prior to a jam forming are monitoring and detection of movement, mechanical or thermal weakening of the ice cover. Permanent measures are also effective and maybe the best option in specific locations. These measures include structures to keep flood waters from inundating areas (e.g., levee) or they can be designed to hold back ice fragments moving downstream (e.g., ice boom and pier structures). Climate change impacts to ice processes are important for Alaska and additional investigations will be needed to quantify the ecologic, hydrologic, and societal impacts.

11 May 2023

Testing of Dry Decontamination Technologies for Chemical, Biological, Radiological, and Nuclear (CBRN) Response

Abstract: This report provides a summary of the results obtained in laboratory-scale testing of dry-decontamination technologies. The purpose of the experiment is to assess nonaqueous technologies to determine the viability of a solution to mitigate chemical, biological, radiological, and nuclear (CBRN) defense, CBRN Response Enterprise, medical casualty care, and cold-weather operational gaps. The Cold Regions Research and Engineering Laboratory (CRREL) assessed the efficacy, via percentage reduction, of four nonaqueous technologies to decontaminate particulate contamination, at three operational temperatures, from three starting challenges. Testing was conducted by CRREL personnel according to protocols developed in conjunction with the Homeland Defense/Civil Support Office Maneuver Support Center of Excellence and the Armed Forces Radiobiology Research Institute (AFRRI) and approved by Joint Program Executive Office CBRN Protection. CRREL subsequently collected data and conducted statistical measures of significance and explored additional questions about the technology capabilities. CRREL personnel then deployed with AFRRI support to Arctic Eagle/Patriot 22 (AE/P-22) for field testing of the technologies and their evaluation from an operational perspective. AE/P-22 allowed for direct, full-scale testing of the technology in conditions approximating a use-case scenario. This report documents the culmination of analysis performed on CRREL- and AFRRI-collected test data results, operational factors, and user inputs.

14 Apr 2023

Live-Fire Validation of Command-Detonation Residues Testing Using an 81 mm IMX-104 Munition

Abstract: Postdetonation energetic residues can have environmental impacts that present a risk to military training-range sustainment. As munitions with new explosive formulations are developed and fielded, quantitative methods for assessing their residues are needed. Command detonation (i.e., static firing) allows residue testing to occur early in the acquisition process; however, its representation of live-fire residue production is uncertain due to differences in the initiation mechanism and cartridge orientation. This study aims to validate residue testing by command detonation through statistical comparison of residue deposition rates between live fire and command detonation. Live-fire residues were collected from fourteen 81 mm IMX-104 mortar cartridges fired onto snow, and deposition rates were compared with previous command-detonation tests of the same munition. Average live-fire deposition rates were 8000 mg NTO (3-nitro-1,2,4-triazol-5-one), 60 mg DNAN (2,4-dinitroanisole), 20 mg RDX (1,3,5-trinitroperhydro-1,3,5-triazine), and 2 mg HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazocane) per cartridge. Compared to command detonation, live fire of the study munition produced significantly greater residues of NTO (p < 0.0001) and RDX (p = 0.01) but not DNAN (p = 0.067). Although absolute deposition rates of some IMX-104 compounds differed, command detonation was successful at predicting the order of magnitude of each IMX-104 compound for the studied 81 mm munition.

14 Apr 2023

A 10-Year Monthly Climatology of Wind Direction: Case-Study Assessment

Abstract: A 10-year monthly climatology of wind direction in compass degrees is developed utilizing datasets from the National Oceanic Atmospheric Administration, Climate Forecast System. Data retrieval methodologies, numerical techniques, and scientific analysis packages to develop the climatology are explored. The report describes the transformation of input data in Gridded Binary format to the Geographic Tagged Image File Format to support geospatial analyses. The specific data sources, software tools, and data-verification techniques are outlined.

24 Mar 2023

Shallow Geothermal Technology, Opportunities in Cold Regions, and Related Data for Deployment at Fort Wainwright

ABSTRACT: The DoD considers improving Arctic capabilities critical (DoD 2019; HQDA 2021). Deployment of shallow geothermal energy systems at cold regions installations provides opportunity to increase thermal energy resilience by lessening dependence on fuel supply and supporting installations’ NetZero transitions. Deployment can be leveraged across facilities, for ex-ample using Fort Wainwright metrics for implementation of geothermal in cold region bases. Fort Wainwright is an extreme case of heating dominant loads owing to harsh conditions in Alaska, making it ideal for proving feasibility in most heating dominant installations. Proven feasibility and potential mass deployment will help reduce emissions and increase resilience across the DoD cold region network. This report introduces the shallow geothermal energy and storage technology combination that would best fit demonstration in Alaska. Focus is on leveraging shallow, low-temperature geothermal for the development of a larger geothermal district heating and cooling (GDHC) system with underground thermal energy storage (UTES) and geothermal heat exchangers (GHX). Such systems are proven in cooling dominant climates, and individual components are proven in heating dominant climates, but deployment of a larger system in a heating dominant climate is not well established. Deployment at Fort Wainwright would represent an improvement in the technology.

21 Mar 2023

Characterization of Pigmented Microbial Isolates for Use in Material Applications

Abstract: Organisms (i.e., plants and microorganisms) contain pigments that allow them to adapt and thrive under stressful conditions, such as elevated ultraviolet radiation. The pigments elicit characteristic spectral responses when measured by active and passive sensors. This research study focused on characterizing the spectral response of three organisms and how they compared to background spectral signatures of a complex environment. Specifically, spectra were collected from a fungus, a plant, and two pigmented bacteria, one of which is an extremophile bacterium. The samples were measured using Fourier transform infrared spectroscopy and discriminated using chemometric means. A top-down examination of the spectral data revealed that organisms could be discriminated from one another through principal component analysis (PCA). Furthermore, there was a strong distinction between the plant and the pigmented microorganisms. Spectral differences resulting in samples with the highest variance from the natural background were identified using PCA loading plots. The outcome of this work is a spectral library of pigmented biological candidates for coatings applications.