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  • Full-Scale Evaluation of Multi-axial Geogrids in Road Applications

    Abstract: The U.S. Army Engineer Research and Development Center (ERDC) constructed a full-scale unsurfaced test section to evaluate the performance of two prototype geogrids, referred to as NX950 and NX750, in road applications. The test section consisted of a 10-in.-thick crushed aggregate surface layer placed over a very weak 2 California Bearing Ratio (CBR) clay subgrade. Simulated truck traffic was applied using one of ERDC’s specially designed load carts outfitted with a single-axle dual wheel truck gear. Rutting performance and instrumentation response data were monitored at multiple traffic intervals. It was found that the prototype geogrids improved rutting performance when compared to the unstabilized test item, and that the test item containing NX950 had the best rutting performance. Further, instrumentation response data indicated that the geogrids reduced measured pressure and deflection near the surface of the subgrade layer. Pressure response data in the aggregate layer suggested that the geogrids redistributed applied pressure higher in the aggregate layer, effectively changing the measured stress profile with an increase in pavement depth.
  • Modernizing Environmental Signature Physics for Target Detection—Phase 3

    Abstract: The present effort (Phase 3) builds on our previously published prior efforts (Phases 1 and 2), which examined methods of determining the probability of detection and false alarm rates using thermal infrared for buried object detection. Environmental phenomenological effects are often represented in weather forecasts in a relatively coarse, hourly resolution, which introduces concerns such as exclusion or misrepresentation of ephemera or lags in timing when using this data as an input for the Army’s Tactical Assault Kit software system. Additionally, the direct application of observed temperature data with weather model data may not be the best approach because metadata associated with the observations are not included. As a result, there is a need to explore mathematical methods such as Bayesian statistics to incorporate observations into models. To better address this concern, the initial analysis in Phase 2 data is expanded in this report to include (1) multivariate analyses for detecting objects in soil, (2) a moving box analysis of object visibility with alternative methods for converting FLIR radiance values to thermal temperature values, (3) a calibrated thermal model of soil temperature using thermal IR imagery, and (4) a simple classifier method for automating buried object detection.
  • Wabash and Ohio River Confluence Hydraulic and Sediment Transport Model Investigation: A Report for US Army Corps of Engineers, Louisville District

    Abstract: Avulsions of the Wabash River in 2008 through 2011 at its confluence with the Ohio River resulted in significant shoaling in the Ohio River. This caused a re-alignment of the navigation channel and the need for frequent dredging. A two-dimensional numerical hydrodynamic model, Adaptive Hydraulics (AdH), was developed to simulate base (existing) conditions and then altered to simulate multiple alternative scenarios to address these sediment issues. The study was conducted in two phases, Phase 1 in 2013 – 2015 and Phase 2 in 2018 – 2020. Field data were collected and consisted of multi-beam bathymetric elevations, bed sediment samples, suspended sediment samples, and discharge and velocity measurements. The model hydrodynamic and sediment transport computations adequately replicated the water surface slope, flow splits, bed sediment gradations, and suspended sediment concentrations when compared with field data. Thus, it was shown to be dependable as a predictive tool. The alternative that produced the most desirable results included a combination of three level-crested emergent dikes on Wabash Island and four submerged dikes on the Illinois shore with a level crest from the bank to the tip of the dike. The selected alternative produced an improved sailing line while maintaining authorized channel depths.
  • Engineering With Nature Website User Guide

    Abstract: The Engineering With Nature (EWN) program is a high-profile effort that aims to deliver cost-effective, broadly beneficial solutions to natural re-source and sustainability challenges across the nation. A portion of this is accomplished through the use of the EWN website, which features news, podcasts, articles, and more. The content on the EWN website serves to educate and inform hundreds of visitors monthly. This content is generated and managed by EWN team members with web development experience, as it requires manually editing the website HTML and staging changes on a development server. With the EWN website 2.0, a new website framework (WordPress) has been implemented that will save content managers time and effort by providing a front-end user interface (UI) to enable the uploading, staging, and approval of new content for the website, along with a visual refresh to herald the impending release of season 2 of the EWN Podcast. This document’s purpose is to demonstrate the functionality of the new EWN website and provide instructional material for those managing content via the new EWN website.
  • High Efficiency Fuel Sleds for Polar Traverses

    Abstract: We describe here the evolution of lightweight, high-efficiency fuel sleds for Polar over-snow traverses. These sleds consist of flexible bladders strapped to sheets of high molecular weight polyethylene. They cost 1/6th, weigh 1/10th and triple the fuel delivered per towing tractor compared with steel sleds. An eight-tractor fleet has conducted three 3400-km roundtrips to South Pole with each travers delivering 320,000 kg of fuel while emitting <1% the pollutants, consuming 1/2 the fuel and saving $1.6 M compared with aircraft resupply. A two-tractor fleet in Greenland recently delivered 83,000 kg of fuel in bladder sleds to Summit with similar benefits. Performance monitoring has revealed that bladder-sled towing resistance is largely governed by sliding friction, which can start high and drop in half over the first 30 min of travel. Frictional heating probably produces a thin water layer that lubricates the sled–snow interface. Consequently, towing resistance depends on the thermal budget of the sled. For example, black fuel bladders increase solar gain and thus decrease sled resistance; data suggest they could double again the fuel delivered per tractor. The outstanding efficiency and low cost of these sleds has transformed fuel delivery to Polar research stations.
  • Use of a Portable Friction Tester on Snow and Ice Pavement

    Abstract: The objective of this project was to determine if portable friction testers could be used for friction measurements on compacted snow and ice surfaces. First, the effect of cold temperatures on the operation, consistency, and accuracy of commercially available portable pavement friction measuring tools was evaluated. Tests entailed a series of experiments in a controlled cold room environment. Two portable fixed slip continuous measurement devices and one deceleration spot measurement device were evaluated. The controlled temperature testing determined how ambient temperature and duration of exposure can affect results, but that with care, the devices could be operated in conditions as cold as ˗25°C. This was followed by using one of the devices on outdoor testing on snow, ice, and asphalt surfaces and compared the portable tester to the well-known SAAB vehicle runway friction tester. Results showed good agreement between the portable tester and the SAAB Friction tester, providing validation for the operational use of a portable tester on frozen surfaces.
  • Microbiome Perturbations During Domestication of the Green June Beetle (Cotinis nitida)

    Abstract: Animal-associated microbiomes are critical to the well-being and proper functioning of the animal host, but only limited studies have examined in-sect microbiomes across different developmental stages. These studies revealed large shifts in microbiome communities, often because of significant shifts in diet during insects’ life cycle. Establishing insect colonies as model laboratory organisms and understanding how to properly feed and care for animals with complex and dynamic life cycles requires improved data. This study examined laboratory-raised green June beetles (Cotinis nitida) captured from the field upon emergence from pupae. Starting with wild-caught adults, two generations of beetles were reared in the laboratory, ending with an entirely laboratory-raised generation of larvae. The study compared the microbiomes of each generation and the microbiomes of larvae to adults. This study suggests that a diet of commercial, washed fruit for adults and commercial, packaged, organic alfalfa meal for larvae resulted in depauperate gut microbiome communities. Fermentative yeasts were completely absent in the laboratory-raised adults, and major bacterial population shifts occurred from one generation to the next, coupled with high morbidity and mortality in the laboratory-raised generation. Providing laboratory-raised beetles fresh-collected fruit and the larvae field-harvested detritus may therefore vastly improve their health and survival.
  • Sampling Interplanetary Dust from Antarctic Air

    Abstract: We built a collector to filter interplanetary dust particles (IDPs) larger than 5 µm from the clean air at the Amundsen Scott South Pole station. Our sampling strategy used long duration, continuous dry filtering of near-surface air in place of short duration, high-speed impact collection on flags flown in the stratosphere. We filtered ~107 m3 of clean Antarctic air through 20 cm diameter, 3 µm filters coupled to a suction blower of modest power consumption (5–6 kW). Our collector ran continuously for 2 years and yielded 41 filters for analyses. Based on stratospheric concentrations, we predicted that each month’s collection would provide 300–900 IDPs for analysis. We identified 19 extraterrestrial (ET) particles on the 66 cm2 of filter examined, which represented ~0.5% of the exposed filter surfaces. The 11 ET particles larger than 5 µm yield about a fifth of the expected flux based on >5 µm stratospheric ET particle flux. Of the 19 ET particles identified, four were chondritic porous IDPs, seven were FeNiS beads, two were FeNi grains, and six were chondritic material with FeNiS components. Most were <10 µm in diameter and none were cluster particles. Additionally, a carbon-rich candidate particle was found to have a small 15N isotopic enrichment, supporting an ET origin. Many other candidate grains, including chondritic glasses and C-rich particles with Mg and Si and FeS grains, require further analysis to determine if they are ET. The vast majority of exposed filter surfaces remain to be examined.
  • Environmental Impact of Metals Resulting from Military Training Activities: A Review

    Abstract: The deposition of metals into the environment as a result of military training activities remains a longterm concern for Defense organizations across the globe. Of particular concern for deposition and potential mobilization are antimony (Sb), arsenic (As), copper (Cu), lead (Pb), and tungsten (W), which are the focus of this review article. The fate, transport, and mobilization of these metals are complicated and depend on a variety of environmental factors that are often convoluted, heterogeneous, and site dependent. While there have been many studies investigating contaminant mobilization on military training lands there exists a lack of cohesiveness surrounding the current state of knowledge for these five metals. The focus of this review article is to compile the current knowledge of the fate, transport, and ultimate risks presented by metals associated with different military training activities particularly as a result of small arms training activities, artillery/mortar ranges, battleruns, rocket ranges, and grenade courts. From there, we discuss emerging research results and finish with suggestions of where future research efforts and training range designs could be focused toward further reducing the deposition, limiting the migration, and decreasing risks presented by metals in the environment. Additionally, information presented here may offer insights into Sb, As, Cu, Pb, and W in other environmental settings.
  • Approaches to Identify and Monitor for Potential Acid Sulfate Soils in an Ecological Restoration Context

    Purpose: Potential acid sulfate soils include materials with the capacity to generate acidity under certain environmental conditions. As such, these soils can pose challenges to ecological restoration projects occurring in wetlands and nearshore environments. To provide guidance for ecosystem restoration practitioners, the following technical note describes acid sulfate soil formation and distribution and then describes techniques for identifying and monitoring acid sulfate soil conditions prior to and following implementation of restoration activities. Finally, this technical note outlines a number of tools and recently published resources to help avoid unintended consequences of acid sulfate soil disturbance and achieve ecological restoration objectives.