2 Feb 2024

The Influence of Mesoscale Atmospheric Convection on Local Infrasound Propagation

Abstract: Infrasound—that is, acoustic waves with frequencies below the threshold of human hearing—has historically been used to detect and locate distant explosive events over global ranges (≥1,000 km). Simulations over these ranges have traditionally relied on large-scale, synoptic meteorological information. However, infrasound propagation over shorter, local ranges (0–100 km) may be affected by smaller, mesoscale meteorological features. To identify the effects of these mesoscale meteorological features on local infrasound propagation, simulations were conducted using the Weather Research and Forecasting (WRF) meteorological model to approximate the meteorological conditions associated with a series of historical, small-scale explosive test events that occurred at the Big Black Test Site in Bovina, Mississippi. These meteorological conditions were then incorporated into a full-wave acoustic model to generate meteorology-informed predictions of infrasound propagation. A series of WRF simulations was conducted with varying degrees of horizontal resolution—1, 3, and 15 km—to investigate the spatial sensitivity of these infrasound predictions. The results illustrate that convective precipitation events demonstrate potentially observable effects on local infrasound propagation due to strong, heterogeneous gradients in temperature and wind associated with the convective events themselves. Therefore, to accurately predict infrasound propagation on local scales, it may be necessary to use convection-permitting meteorological models with a horizontal resolution ≤4 km at locations and times that support mesoscale convective activity.

2 Feb 2024

An MCA Linear Additive Method for Research Project Analysis

Abstract: This report describes a business intelligence (BI) model developed by the Cold Regions Research and Engineering Laboratory (CRREL) to evaluate multiple projects simultaneously and help researchers learn descriptive phrases found in alignment sources representative of their projects. The BI model combines the linear additive model with the analytical hierarchy process to take advantage of the qualitative and quantitative nature of both methods. The model has five variations, all built along the same objectives but with different criteria due to the specialized emphasis areas of each variation. The BI model operates around three central concepts for evaluating the projects: Alignment Variables, Timing, and Customer Relationship. A use-case scenario with ten projects shows the effectiveness of the model and compares it with another model from the United States Military Academy. This new BI model will assist researchers in developing and proposing research ideas that are more relevant and fundable.

31 Jan 2024

Verification of Current Los Angeles (LA) Abrasion Test Criterion for Aggregate Degradation in Airfield Asphalt Pavements

Abstract: Low-quality mineral aggregates can potentially lead to production, construction, and long-term performance-related problems in asphalt concrete pavements. Therefore, effective qualification criteria for mineral aggregates are paramount. This study was performed to investigate the effectiveness of the Los Angeles abrasion (LAA) test to assess the abrasion resistance of coarse aggregates commonly used in airfield asphalt paving. The LAA test acceptance criteria currently specified by state departments of transportation were examined and compared to the current Department of Defense criterion. Additionally, recent experiences during a forensic evaluation to identify potential sources of excessive presence of foreign object debris on an airfield runway are also briefly discussed in this report. The LAA test and associated acceptance criterion in Unified Facilities Guide Specification (UFGS) 32 12 15.13 were evaluated by testing 24 aggregate sources from various US locations. Also, the Micro-Deval abrasion test was performed as a surrogate abrasion resistance test. Sufficient evidence was not found to suggest adjustments to current LAA test criterion or to recommend the use of an alternative abrasion test. The current UFGS specifications should be improved to provide a more thorough aggregate testing protocol and detailed guidelines regarding aggregate sampling and testing frequency during design and construction of asphalt pavements.

23 Jan 2024

Historic Context for the WWII Internment and Prisoner-of-War (POW) Compound at Fort McCoy, Wisconsin

Abstract: This report provides a comprehensive historic context for the enemy alien internment compound and prisoner-of-war (POW) compound at Fort McCoy, Wisconsin, during World War II (WWII). Through primary and secondary sources, it illustrates the development of the internment and POW program at the installation, the built environment, labor details, and aspects of daily life. Although buildings associated with the internment and POW compound are no longer extant, researchers georeferenced historic maps of the compound to create digital footprints of the demolished infrastructure. Additionally, researchers generated and analyzed lidar returns to accentuate the signatures of former building foundations. Together, these processes can help fieldwork investigators determine the approximate locations of former internment and POW infrastructure.

22 Jan 2024

Framework Development for Rapid Assessment and Economic Valuation of Feral Swine Damage to Wetland Terrain: A Pilot Study at US Army Corps of Engineers–Somerville Lake, Texas

Abstract: The increased spread and presence of feral swine on sensitive natural resources landscapes like wetlands has become a considerable concern on lands managed by the US Army Corps of Engineers. In August 2021 a pilot study was carried out at Somerville Lake, Texas, as the first step in a three-year research plan to develop an ecological-economic framework for feral swine damage assessments (FSDA) and valuation. The study sought to quantify and value soil disturbance caused by feral swine trampling, rooting, and wallowing on wetland soils. The primary objective—to develop and test a rapid FSDA prototype—was achieved and represents an important first step to creating a quick and user-friendly damage-assessment framework that also estimates the economic value of the damage observed. With continued testing and development, this rapid FSDA protocol will be of use to all who manage feral swine impacts on landscapes with wetland ecosystems, and findings from this information will be of use for scientifically informed cost-benefit analysis and management decision-making.

22 Jan 2024

Considerations for Integrating Ecological and Hydrogeomorphic Models: Developing a Comprehensive Marsh Vegetation Model

PURPOSE: Predictive models for salt marsh management require a systems perspective that recognizes the dynamic interactions between physical and ecological processes. It is critical to link physical process and landscape evolution models to quantify hydro-eco-geomorphic feedbacks in marsh environments. A framework that explicitly defines how to integrate these disparate models is a necessary step towards developing a comprehensive marsh model. This technical note (TN) proposes an approach to integrate existing hydrodynamic and geomorphic models with a mechanistic vegetation model into a coupled framework to better simulate salt marsh evolution.

22 Jan 2024

Amphibious Uncrewed Ground Vehicle for Coastal Surfzone Survey

Abstract: The capability of a commercial off-the-shelf amphibious bottom crawling robot is explored for surveying seamless topography and bathymetry across the beachface, surfzone, and very nearshore. A real-time-kinematic (RTK) antenna on a mast was added to the robotic platform, a Bayonet-350 (previously the C2i SeaOx). Data collected from the robot were compared with those collected by the Coastal Research Amphibious Buggy (CRAB) and the Lighter Amphibious Resupply Cargo (LARC), unique amphibious vessels capable of collecting seamless topography and bathymetry in use for decades at the US Army Engineer Research and Development Center’s Field Research Facility (FRF). Data were compared on five different days in a range of wave conditions (Hs < 1 m in 8-m depth) resulting in a root-mean square difference of 8.7 cm and bias of 2 cm for 24 different cross-shore profile comparisons. Additionally, a repeatability test was performed to assess measurement uncertainty. The repeatability test indicated a total vertical uncertainty (TVU) of 5.8 cm, with the highest spatial error at the shoreline.

12 Jan 2024

An Elastic-Inelastic Model and Embedded Bounce-Back Control for Layered Printing with Cementitious Materials

Abstract: This paper presents a finite-deformation model for extrusion-based layered printing with cementitious materials. The evolution of mechanical properties as the printed material cures and stiffens results in nonphysical reduction in the magnitude of elastic strains when standard constitutive models are employed. This elastic recovery of the printing induced deformation contradicts the experimentally observed behavior of the printed cementitious materials that harden at a nearly-frozen deformed state. A thermodynamically motivated constraint on the evolution of elastic strains is imposed on the constitutive model to remedy the nonphysical bounce-back effect. An algorithm that is based on a strain-projection technique for the elastic part of deformation is developed that complements the inelastic response given by the Drucker–Prager model. It is then embedded in a finite strain finite element framework for the modeling and simulation of cure hardening and inelastic response of the early age cementitious materials. A ghost mesh method is proposed for continuous layer-wise printing of the material without the need for intermittent mesh generation technique or adaptive remeshing methods. The model is validated via comparison with experimental data and representative test cases are presented that investigate the mathematical and computational attributes of the proposed model.

12 Jan 2024

Levees and Dams at Fort Riley, Kansas, and the Response to the 1951 Flood

Abstract: This project provides a historic context and inventory for the levees and dams constructed at Fort Riley, Kansas. The purpose of this historic con-text and inventory is to determine the levees and dams’ eligibility for listing in the National Register of Historic Places (NRHP). Determinations of eligibility to the NRHP are then made based on the significance of the levees and dams and the degree to which they retain their integrity for conveying that significance. The authors inventoried and evaluated three levees and two lake dams on the installation. Based on the historic context and inventory, researchers for this project have determined that none of the levees and dams are eligible for the inclusion in the NRHP nor was there enough evidence for a noncontiguous historic district at Fort Riley.

11 Jan 2024

Classifying and Benchmarking High-Entropy Alloys and Associated Materials for Electrocatalysis: A Brief Review of Best Practices

Abstract: In light of the immense compositional diversity of high-entropy materials (HEMs) recently reported (e.g., high-entropy chalcogenides, perovskites, ceramics, etc.) and the relatively amorphous definition of High-Entropy, it is imperative that consistent material classification and benchmarking practices be employed to facilitate comparison between reported figures of merit. In this opinion, an updated form of the numerical high entropy definition is reviewed, which renders a universal entropy metric applicable to high-entropy alloys and emerging HEMs alike. Analytical methods to verify the existence of a solid-solution microstructure, elucidate atomic valence states, and probe atomic disorder are discussed with literature examples to facilitate the physical classification of HEMs. Electrocatalytic benchmarking is discussed in the context of water splitting reactions and best practices are reviewed for determining the electrocatalytically active surface area, reaction overpotential, and electrocatalyst stability.