14 Feb 2024

Hydraulic Sorting of Dredged Sediment in a Pipeline: An Evaluation of the Sediment Distribution Pipe

Abstract: The US Army Corps of Engineers (USACE) recently established a goal to beneficially use 70% of material dredged from the nation’s navigable waterways by the year 2030. Most of the sediments dredged by the USACE are heterogeneous mixtures of mud and sand, which can limit beneficial use of dredged material (BUDM) applications. Innovative technologies that can sort material during the dredging process are needed to help increase BUDM practices. This investigation sought to evaluate the ability of a sediment distribution pipe (SDP) to sort particles during transport in a pipeline. Field demonstrations were conducted during dredged material placements at Sturgeon Island, New Jersey. Velocity within the pipeline was found to be inadequate for efficient hydraulic sorting of fines (<75 μm) and produced inconclusive results. Small scale laboratory SDP experiments found that effluent from the SDP holes had an altered sediment texture compared to the initial slurry and that hydraulic sorting was occurring within the pipeline. However, outflow from the SDP holes was inconsistent, and typically >90% of the sediment mass was discharged out the end of the pipeline. Sorting efficiency of the SDP could not be accurately assessed in the current experimental configuration.

9 Feb 2024

Overview of Microscale Analytical Methods for the Quantitative Detection of Bioaccumulative Contaminants in Small Tissue Masses

Abstract: For many bioaccumulation studies, generation of large sample masses of exposed organisms is challenging or even prohibitive. Therefore, the use of smaller sample masses for analysis without compromising data quality or quantitative level achieved is desirable. To this end, a variety of microanalytical procedures have been developed that used 1 g or less of tissue to address specific experimental challenges. However, these methods have not been systematically evaluated or published. The present work evaluates the current state of the microanalytical methods reported and identifies additional needs that would benefit US Army Corps of Engineers (USACE) research and navigation dredging programs. Discussions with commercial laboratories revealed that they typically do not accept small sample masses and require individual sample masses ranging from 10 to 20 g wet weight of tissue per analysis. If they do analyze a small mass sample, they routinely do not modify their standard process, resulting in detection and reporting limits orders of magnitude higher; therefore, essentially useless nondetect data are generated for regulatory decisions. To address the lack of commercial availability of microanalytical methods, we recommend pursuing method development and subsequent validation of microscale extraction and analysis of a variety of common contaminant compounds in tissue matrices.

7 Feb 2024

Ecological Modeling of Microbial Community Composition under Variable Temperatures

Abstract: Soil microorganisms interact with one another within soil pores and respond to external conditions such as temperature. Data on microbial community composition and potential function are commonly generated in studies of soils. However, these data do not provide direct insight into the drivers of community composition and can be difficult to interpret outside the context of ecological theory. In this study, we explore the effect of abiotic environmental variation on microbial species diversity. Using a modified version of the Lotka-Volterra Competition Model with temperature-dependent growth rates, we show that environmentally relevant temperature variability may expand the set of temperature-tolerance phenotype pairs that can coexist as two-species communities compared to constant temperatures. These results highlight a potential role of temperature variation in influencing microbial diversity. This in turn suggests a need to incorporate temperature into predictive models of microbial communities in soil and other environments. We recommend future work to parameterize the model applied in this study with empirical data from environments of interest, and to validate the model predictions using field observations and experimental manipulations.

6 Feb 2024

USACE Freshwater Harmful Algal Bloom Research and Development Initiative

Abstract: Harmful Algal Blooms (HABs) represent a significant and costly threat to our nation’s economy and natural resources. This report outlines the US Army Corps of Engineers, Engineer Research and Development Center’s (USACE-ERDC’s) approach to deliver scalable technologies for prevention, early detection, and management of HABs to reduce HAB event frequency, severity, and duration.

6 Feb 2024

Dynamic Tensile Behavior of Laser-Directed Energy Deposition and Additive Friction Stir-Deposited AerMet 100

Abstract: Quasi-static and high-rate tensile experiments were used to examine the strain rate sensitivity of laser-directed energy deposition (L-DED)- and additive friction stir deposition (AFSD)-formed AerMet 100 ultrahigh-strength steel-additive manufactured builds. Electron backscattered diffraction (EBSD) revealed similar as-deposited grain sizes between the two AM processes at approximately 24 µm and 17 µm for the L-DED and AFSD samples, respectively. The strain hardening rate, θ, revealed little change in the overall hardening observed in the L-DED and AFSD materials, with a consistent hardening in the quasi-static samples and three identifiable regions in that of the high-rate tested materials. The L-DED deposited materials displayed average ultimate tensile strength values of 1835 and 2902 MPa for the 0.001 s−1 and 2500 s−1 strain rates, respectively and the AFSD deposited materials displayed ultimate tensile strength values of 1928 and 3080 MPa for the 0.001 s−1 and 2500 s−1 strain rates, respectively. Overall, the strength for both processes displayed a positive strain rate sensitivity, with increases in strength of ~1000 MPa for both processes. Fractography revealed significant solidification voids in the laser DED material and poor layer adhesion in the AFSD material.

2 Feb 2024

Extreme Cold Weather Airfield Damage Repair Testing at Goose Bay Air Base, Canada

Abstract: Rapid Airfield Damage Recovery (RADR) technologies have proven successful in temperate and subfreezing temperatures but have not been evaluated in extreme cold weather temperatures near 0°F. To address this capability gap, laboratory-scale and full-scale testing was conducted at these temperatures. Methods developed for moderate climates were adapted and demonstrated alongside methods that used snow harvested on-site as compacted backfill. After only a few days of training, seven experimental repairs were conducted by Canadian airmen at Goose Bay Air Base in Labrador, Canada, and load tested with a single-wheel C-17 load cart. Existing RADR technologies performed adequately despite the freezing temperatures, with the main tactic, techniques, and procedures modification being an increased cure time for the rapid-setting concrete surface material. Compacted snow-water slurry methods also performed well, demonstrating their ability to withstand over 500 passes of single-wheel C-17 traffic after sufficient freezing time.

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.