27 Sep 2021

Observation of Silver Carp Spawning in a Mississippi River Tributary

Purpose: This technical note seeks to better understand spawning cues of invasive carp for management and control purposes.

24 Sep 2021

Autonomous Transport Innovation: A Review of Enabling Technologies

Purpose: This document is the first of the technical note series under the Autonomous Transport Innovation (ATI) research program. The series intends to be an introduction on autonomous vehicles (AVs), their testing, and associated infrastructure. A review of technologies that enable vehicle autonomy is necessary to provide the basis for understanding vehicle performance in testing scenarios and in actual use.

24 Sep 2021

Autonomous Transport Innovation: The Regulatory Environment of Autonomous Vehicles

Purpose: This technical note series under the Autonomous Transport Innovation research program is intended to be a primer on autonomous vehicles (AVs), their testing, and associated infrastructure. A review of the regulatory environment for autonomous vehicles is necessary to define rules imposed on technology or operations of autonomous vehicles in various capacities. Acknowledging such regulation will aid in productive closed-course site development by structuring the course based on what autonomous vehicle developers and manufacturers must program their vehicles to adhere to in a given setting.

24 Sep 2021

Environmental Life Cycle Assessment on CNTRENE® 1030 Material and CNT Based Sensors

Abstract: This report details a study investigating the environmental impacts associated with the development and manufacturing of carbon nanotube (CNT)–based ink (called CNTRENE 1030 material) and novel CNT temperature, flex, and moisture sensors. Undertaken by a private-public partnership involving Brewer Science (Rolla, Missouri), Jordan Valley In-novation Center of Missouri State University (Springfield, Missouri), and the US Army Engineer Research and Development Center (Vicksburg, Mississippi), this work demonstrates the environmental life cycle assessment (ELCA) methodology as a diagnostic tool to pinpoint the particular processes and materials posing the greatest environmental impact associated with the manufacture of the CNTRENE material and CNT-based sensor devices. Additionally, ELCA tracked the degree to which optimizing the device manufacturing process for full production also changed its predicted marginal environmental impacts.

24 Sep 2021

Phytomanagement of Soil and Groundwater at the Niagara Falls Storage Site (NFSS) Using Hybridized Trees

Abstract: The Manhattan Engineer District previously used the 191-acre Niagara Falls Storage Site (NFSS) in Niagara County, New York, to store radioactive residues and wastes from uranium (U) ore processing. At present, management practices will determine whether enhanced evapotranspiration rates produced by hybridized shrub willow cuttings planted in 2016 will affect groundwater hydrology. Two shrub willow varieties were planted in an approximately one-half acre area to examine growth performance along a U impacted sanitary sewer line. Additionally, control plots will compare the effectiveness of shrub willows to unplanted areas. Observations of the planted area after 18 months showed success of shrub willow growth with increasing biomass. Chemical analysis from tree tissue samples of the field study showed no significant uptake of U or thorium (Th) to date. A greenhouse study conducted in parallel to the field study tested the willows under controlled greenhouse conditions and evaluated their ability to grow and accumulate contaminants under controlled conditions. Results from the greenhouse study demonstrated that U accumulation was minimal. Thus, this study demonstrates that the shrub willows are not accumulators of U or Th, an advantageous characteristic that implies stabilized contaminants in the soil and no translocation of U into the aboveground biomass.

24 Sep 2021

Leveraging Chemical Actinometry and Optical Radiometry to Reduce Uncertainty in Photochemical Research

Abstract: Subtle aspects of illumination sources and their characterization methods can introduce significant uncertainty into the data gathered from light-activated experiments, limiting their reproducibility and technology transition. Degradation kinetics of methyl orange (MO) and carbamazepine (CM) under illumination with TiO2 were used as a case study for investigating the role of incident photon flux on photocatalytic degradation rates. Valerophenone and ferrioxalate actinometry were paired with optical radiometry in three different illumination systems: xenon arc (XE), tungsten halogen (W-H), and UV fluorescent (UV-F). Degradation rate constants for MO and CM varied similarly among the three light systems as k W-H < kiv-F < kXE, implying the same relative photon flux emission by each light. However, the apparent relative photon flux emitted by the different lights varied depending on the light characterization method. This discrepancy is shown to be caused by the spectral distribution present in light emission profiles, as well as absorption behavior of chemical actinometers and optical sensors. Data and calculations for the determination of photon flux from chemical and calibrated optical light characterization is presented, allowing us to interpret photo-degradation rate constants as a function of incident photon flux. This approach enabled the derivation of a calibrated ‘rate-flux’ metric for evaluating and translating data from photocatalysis studies.

23 Sep 2021

Efficacy of Florpyrauxifen-benzyl for Eurasian Watermilfoil Control and Nontarget Illinois Pondweed, Elodea, and Coontail Response

Purpose: This research evaluated low concentrations and short exposure times of the recently registered aquatic herbicide florpyrauxifen-benzyl (4-amino-3-chloro-6-(4-chloro-2-fluoro-3-methoxyphenyl)-5-fluoro-pyridine-2-benzyl ester) on the target plant Eurasian watermilfoil (Myriophyllum spicatum L., hereafter referred to as EWM) as well as selectivity towards the nontarget submersed species Illinois pondweed (Potamogeton illinoensis Morong), elodea (Elodea canadensis Michx.), and coontail (Ceratophyllum demersum L.)

23 Sep 2021

Efficacy of Florpyrauxifen-benzyl on Dioecious Hydrilla and Hybrid Water Milfoil - Concentration and Exposure Time Requirements

Abstract: This study conducted small-scale trials under various concentration and exposure time (CET) scenarios to determine florpyrauxifen-benzyl activity on dioecious hydrilla and hybrid watermilfoil and determine impact on water stargrass and elodea. Hydrilla treated with 12, 24, or 36 μg active ingredient (a.i.) L⁻¹ florpyrauxifen-benzyl and exposed for 12, 24, or 48 hr under outdoor mesocosm conditions was reduced in biomass by 30-75% at 8 weeks after treatment (WAT). An additional hydrilla trial at the same herbicide concentrations, but under longer exposures (24, 72, or 168 hr), resulted in 33–85% plant control. Under indoor conditions, hybrid watermilfoil dry weight decreased 98–100% with subsurface applications of florpyrauxifen-benzyl under CET scenarios of 3–12 μg a.i. L⁻¹ at 3–24 hr exposure times in a growth chamber trial. Under shorter exposure periods (0.5–4 hr) in a follow-up trial, low doses (3–9 μg a.i. L⁻¹) achieved 50–100% control of hybrid watermilfoil. In the same trial, the nontarget species water stargrass and elodea proved relatively tolerant to the florpyrauxifen-benzyl at doses up to 6 μg a.i. L⁻¹ (4 hr exposure) and 9 μg a.i. L⁻¹ (1 hr exposure). These small-scale trials demonstrate florpyrauxifen-benzyl’s potential to selectively manage invasive species.

23 Sep 2021

Comparison of Generic and Proprietary Aquatic Herbicides for Control of Invasive Vegetation; Part 3: Submersed Plants

Abstract: Herbicide selection is key to efficiently managing nuisance vegetation in our nation’s waterways. After selecting the active ingredient, there still remains multiple proprietary and generic products to choose from. Recent small-scale research has been conducted to compare the efficacy of these herbicides against floating and emergent species. Therefore, a series of mesocosm and growth chamber trials were conducted to evaluate subsurface applications of the following herbicides against submersed plants: diquat versus coontail (Ceratophyllum demersum L.), hydrilla (Hydrilla verticillata L.f. Royle), southern naiad (Najas guadalupensis (Sprengel) Magnus), and Eurasian watermilfoil (Myriophyllum spicatum L.); flumioxazin versus coontail, hydrilla, and Eurasian watermilfoil; and triclopyr against Eurasian watermilfoil. All active ingredients were applied at concentrations commonly used to manage these species in public waters. Visually, all herbicides within a particular active ingredient performed similarly with regard to the onset and severity of injury symptoms throughout the trials. All trials, except diquat versus Eurasian watermilfoil, resulted in no differences in efficacy among the 14 proprietary and generic herbicides tested, and all herbicides provided 43%–100% control, regardless of active ingredient and trial. Under mesocosm and growth chamber conditions, the majority of the generic and proprietary herbicides evaluated against submersed plants provided similar control.

23 Sep 2021

Field Site Analysis of Giant Salvinia Nitrogen Content and Salvinia Weevil Density

Abstract: In 2012, a giant salvinia (Salvinia molesta Mitchell) biological control project was initiated in Louisiana. Although similar quantities of salvinia weevils (Cyrtobagous salviniae Calder and Sands) were released at all sites, weevil densities were highly variable among sites. Additionally, signs of plant nitrogen depletion (yellowing plants) were observed at some sites. Because it is well known that plant nutrition can affect the success of a biocontrol agent because of slowed development and/or reduced fecundity, the correlation between giant salvinia nitrogen content and Salvinia weevil density was investigated during the growing seasons of the second and fourth years. During 2013, weevils were reintroduced to sites, and the magnitude of adult weevil density increase varied by site. Giant salvinia nitrogen content varied among sites and sampling dates. Upper Big Break plants had greater nitrogen than all other sites during 75% of sampling dates. Additionally, adult and larval densities were significantly correlated to plant nitrogen content. During 2015, trends were less distinct and weevil densities and nitrogen content varied based on the interaction between sampling date and site, but a significant correlation was not detected. Results confirmed published reports of the importance of plant nitrogen content to salvinia weevil productivity. Additional studies are warranted to evaluate and understand the role of nitrogen at giant salvinia biocontrol field sites.