1 Dec 2020

Evaluation of New Endothall and Florpyrauxifen-benzyl Use Patterns for Controlling Crested Floating Heart and Giant Salvinia

Purpose: The purpose of this research was to (1) evaluate concentration exposure time (CET) relationships for florpyrauxifen-benzyl (ProcellaCOR) for control of the floating leaved plant crested floating heart (Nymphoides cristata, CFH) and (2) evaluate foliar applications of endothall (Aquathol K) for control of CFH and the floating fern giant salvinia (Salvinia molesta).

1 Dec 2020

Snow-Covered Obstacles’ Effect on Vehicle Mobility

ABSTRACT:  The Mobility in Complex Environments project used unmanned aerial systems (UAS) to identify obstacles and to provide path planning in forward operational locations. The UAS were equipped with remote-sensing devices, such as photogrammetry and lidar, to identify obstacles. The path-planning algorithms incorporated the detected obstacles to then identify the fastest and safest vehicle routes. Future algorithms should incorporate vehicle characteristics as each type of vehicle will perform differently over a given obstacle, resulting in distinctive optimal paths. This study explored the effect of snow-covered obstacles on dynamic vehicle response. Vehicle tests used an instrumented HMMWV (high mobility multipurpose wheeled vehicle) driven over obstacles with and without snow cover. Tests showed a 45% reduction in normal force variation and a 43% reduction in body acceleration associated with a 14.5 cm snow cover. To predict vehicle body acceleration and normal force response, we developed two quarter-car models: rigid terrain and deformable snow terrain quarter-car models. The simple quarter models provided reasonable agreement with the vehicle test data. We also used the models to analyze the effects of vehicle parameters, such as ground pressure, to understand the effect of snow cover on vehicle response.

16 Nov 2020

Long-Term Stability and Efficacy of Historic Activated Carbon (AC) Deployments at Diverse Freshwater and Marine Remediation Sites

Abstract: A number of sites around the United States have used activated carbon (AC) amendments to remedy contaminated sediments. Variation in site-specific characteristics likely influences the long-term fate and efficacy of AC treatment. The long-term effectiveness of an AC amendment to sediment is largely unknown, as the field performance has not been monitored for more than three years. As a consequence, the focus of this research effort was to evaluate AC’s long-term (6–10 yr) performance. These assessments were performed at two pilot-scale demonstration sites, Grasse River, Massena, New York and Canal Creek, Aberdeen Proving Ground (APG), Aberdeen, Maryland, representing two distinct physical environments. Sediment core samples were collected after 6 and 10 years of remedy implementation at APG and Grasse River, respectively. Core samples were collected and sectioned to determine the current vertical distribution and persistence of AC in the field. The concentration profile of polychlorinated biphenyls (PCBs) in sediment pore water with depth was measured using passive sampling. Sediment samples from the untreated and AC-treated zones were also assessed for bioaccumulation in benthic organisms. The data collected enabled comparison of AC distribution, PCB concentrations, and bioaccumulation measured over the short- and long-term (months to years).

16 Nov 2020

Magnetorheological Composite Materials (MRCMs) for Instant and Adaptable Structural Control

Abstract: Magnetic responsive materials can be used in a variety of applications. For structural applications, the ability to create tunable moduli from relatively soft materials with applied electromagnetic stimuli can be advantageous for light-weight protection. This study investigated magnetorheological composite materials involving carbonyl iron particles (CIP) embedded into two different systems. The first material system was a model cementitious system of CIP and kaolinite clay dispersed in mineral oil. The magnetorheological behaviors were investigated by using parallel plates with an attached magnetic accessory to evaluate deformations up to 1 T. The yield stress of these slurries was measured by using rotational and oscillatory experiments and was found to be controllable based on CIP loading and magnetic field strength with yield stresses ranging from 10 to 104 Pa. The second material system utilized a polystyrene-butadiene rubber solvent-cast films with CIP embedded. The flexible matrix can stiffen and become rigid when an external field is applied. For CIP loadings of 8% and 17% vol %, the storage modulus response for each loading stiffened by 22% and 74%, respectively.

16 Nov 2020

Publication Notification: Distribution of the Two-Point Product of Complex Amplitudes in the Fully Saturated Scattering Regime

Abstract:  This Letter considers probability density functions (pdfs) involving products of the complex amplitudes observed at two points (which may, in general, involve separations in space, time, or frequency) in conditions of fully saturated scattering. First, the pdf is derived for the product of the complex amplitude at one point with the conjugate of the complex amplitude at another point. It is shown that the real and imaginary parts of this product each have a variance gamma pdf. Second, expressions are derived for several joint pdfs involving complex amplitude products and powers at two points.

16 Nov 2020

Publication Notification: Fort McCoy WWII Buildings and Landscapes

Abstract: The U.S. Congress codified the National Historic Preservation Act of 1966 (NHPA) mostly through the National Register of Historic Places (NRHP), which requires federal agencies to address their cultural resources. Section 110 of the NHPA requires federal agencies to inventory and evaluate their cultural resources, and Section 106 requires them to determine the effect of federal undertakings on those potentially eligible for the NRHP. This report provides a World War II development history and analysis of 786 buildings, and determinations of eligibility for those buildings, on Fort McCoy, Wisconsin. Evaluation of the WWII buildings and landscape concluded that there are too few buildings with integrity to form a cohesive historic district. While the circulation patterns and roads are still intact, the buildings with integrity are scattered throughout the cantonment affecting the historic character of the landscape. Only Building 100 (post headquarters), Building 656 (dental clinic), and Building 550 (fire station) are ELIGIBLE for listing on the NRHP at the national level under Criterion A for their association with World War II temporary building construction (1942-1946) and under Criterion C for their design, construction, and technological innovation.

5 Nov 2020

Discover ERDC Knowledge Management Representative (KMR) User’s Guide

Abstract: Knowledge management plays a vital role in the successful execution on research projects at the U.S. Army Engineer Research and Development Center (ERDC). Accumulating and building upon knowledge is the cornerstone of the research and development process. Maintaining and providing access to knowledge is essential to the successful execution of research programs. An initiative to improve access to knowledge and the tools available to researchers was started by the Office of Research and Technology Transfer (ORRT). The result of that initiative is a knowledge portal called Discover ERDC. This document provides a detailed look on maintaining content on the Discover ERDC site from a Knowledge Management Representative viewpoint, and how help can be provided to those assigned to manage the content.

5 Nov 2020

Fort McCoy, Wisconsin Building 550 Maintenance Plan

Abstract: Building 550 (former World War II fire station) is located on Fort McCoy, Wisconsin, and was recommended eligible for the National Register of Historic Places (NRHP) in 2018 (Smith and Adams 2018). The building is currently vacant. It is an intact example of an 800 Series World War II fire station with character-defining features of its period of significance from 1939 to 1946 on its exterior and interior. All buildings, especially historic ones, require regular planned maintenance and repair. The most notable cause of historic building element failure and/or decay is not the fact that the historic building is old, but rather it is caused by incorrect or inappropriate repair and/or basic neglect of the historic building fabric. This document is a maintenance manual compiled with as-is conditions of construction materials of Building 550. The Secretary of Interior Guidelines on rehabilitation and repair per material are discussed to provide the cultural resources manager at Fort McCoy a guide to maintain this historic building. This report satisfies Section 110 of the National Historic Preservation Act (NHPA) of 1966 as amended and will help the Fort McCoy Cultural Resources Management office to manage this historic building.

5 Nov 2020

Evaluating the Conductive Properties of Melanin-Producing Fungus, Curvularia lunata, after Copper Doping

ABSTRACT:  Melanins are pigmented biomacromolecules found throughout all do-mains of life. Of melanins’ many unique properties, their malleable electrically conductive properties and their ability to chelate could allow them to serve as material for bioelectronics. Studies have shown that sheets or pellets of melanin conduct low levels of electricity; however, electrical conductance of melanin within a cellular context has not been thoroughly investigated. In addition, given the chelating properties of melanin, it is possible that introducing traditionally conductive metal ions could improve the conductivity. Therefore, this study investigated the conductive properties of melanized cells and how metal ions change these. We measured the conductivity of pulverized Curvularia lunata, a melanized filamentous fungi, with and without the addition of copper ions. We then compared the conductivity measurements of the fungus to chemically synthesized, commercially bought melanin. Our data showed that the conductivity of the melanized fungal biomass was an order of magnitude higher when grown in the presence of copper. However, it was two orders of magnitude less than that of synthetic melanin. Interestingly, conductance was measurable despite additional constituents in the pellet that may inhibit conductivity. Therefore, these data show promising results for using melanized cells to carry electrical signals.

5 Nov 2020

A Measurement System for the Study of Nonlinear Propagation Through Arrays of Scatterers

Abstract: Various experimental challenges exist in measuring the spatial and temporal field of a nonlinear acoustic pulse propagating through an array of scatterers. Probe interference and undesirable high-frequency response plague typical approaches with acoustic microphones, which are also limited to resolving the pressure field at a single position. Measurements made with optical methods do not have such drawbacks, and schlieren measurements are particularly well suited to measuring both the spatial and temporal evolution of nonlinear pulse propagation in an array of scatterers. Herein, a measurement system is described based on a z-type schlieren setup, which is suitable for measuring axisymmetric phenomena and visualizing weak shock propagation. In order to reduce directivity and initiate nearly spherically-symmetric propagation, laser induced breakdown serves as the source for the nonlinear pulse. A key component of the schlieren system is a standard schliere, which allows quantitative schlieren measurements to be performed. Sizing of the standard schliere is aided by generating estimates of the expected light refraction from the nonlinear pulse, by way of the forward Abel transform. Finally, considerations for experimental sequencing, image capture, and a reconfigurable rod array designed to minimize spurious wave interactions are specified.