29 Sep 2023

Low Size, Weight, Power, and Cost (SWaP-C) Payload for Autonomous Navigation and Mapping on an Unmanned Ground Vehicle

Abstract: Autonomous navigation and unknown environment exploration with an unmanned ground vehicle (UGV) is extremely challenging. This report investigates a mapping and exploration solution utilizing low size, weight, power, and cost payloads. The platform presented here leverages simultaneous localization and mapping to efficiently explore unknown areas by finding navigable routes. The solution utilizes a diverse sensor payload that includes wheel encoders, 3D lidar, and red-green-blue and depth cameras. The main goal of this effort is to leverage path planning and navigation for mapping and exploration with a UGV to produce an accurate 3D map. The solution provided also leverages the Robot Operating System

29 Sep 2023

Arctic Seed Sterilization and Germination

Abstract: We conducted growth chamber experiments to overcome challenges of native seed germination relating to disease and germination time. We selected five northern species, Eriophorum vaginatum, E. virginicum, Anemone patens var. multifida, Polemonium reptans, and Senecio congestus, for their native ranges and commercial-nursery availability. Recommended stratification time for each species was either unknown or a minimum of 60 days. Seeds were sterilized with 70% ethanol, 10% hydrogen peroxide, or UVC light to identify which method most effectively prevented pathogen infection. To determine if stratification time could be reduced, seeds underwent a 30-day cold, moist stratification. We tested which growth medium was most conducive to germination of the sterilized, stratified seeds: filter paper or sterilized potting soil. In a separate experiment, we tested if three different levels of gibberellic acid (GA3; 0, 500, and 1000 ppm) could reduce stratification time to 15 days. The 70% ethanol was effective in a seed surface sterilization; an average of 84% of all seeds for all species treated showed no contamination. Germination following a 30-day cold, moist stratification was unsuccessful for most species tested in both growth media. Here, 1000 ppm GA3 with a 15-day cold, moist stratification showed considerable success with P. reptans.

29 Sep 2023

Microbial Activity in Dust-Contaminated Antarctic Snow

Abstract: During weather events, particles can accumulate on the snow near the Pegasus ice and Phoenix compacted-snow Runways at the US McMurdo Station in Antarctica. The deposited particles melt into the surface, initially forming steep-sided holes, which can widen into patches of weak and rotten snow and ice. These changes negatively impact the ice and snow runways and snow roads trafficked by vehicles. To understand the importance of microbes on this process, we examined deposited dust particles and their microbial communities in snow samples collected near the runways. Snow samples were analyzed at the Cold Regions Research and Engineering Laboratory where we performed a respiration study to measure the microbial activity during a simulated melt, isolated microorganisms, examined particle-size distribution, and performed 16S rRNA gene sequencing. We measured higher levels of carbon dioxide production from a sample containing more dust than from a sample containing less dust, a finding consistent with viable dust-associated microbial communities. Additionally, eleven microorganisms were isolated and cultured from snow samples containing dust particles. While wind patterns and satellite images suggest that the deposited particles originate from nearby Black Island, comparisons of the particle size and chemical composition were inconclusive.

29 Sep 2023

Plant Phenology Drives Seasonal Changes in Shear Stress Partitioning in a Semi-Arid Rangeland

Abstract: Accurate representation of surface roughness in predictive models of aeolian sediment transport and dust emission is required for model accuracy. While past studies have examined roughness effects on drag partitioning, the spatial and temporal variability of surface shear velocity and the shear stress ratio remain poorly described. Here, we use a four-month dataset of total shear velocity (u*) and soil surface shear velocity (us*) measurements to examine the spatiotemporal variability of the shear stress ratio (R) before, during, and after vegetation green-up at a honey mesquite (Prosopis glandulosa Torr.) shrub-invaded grassland in the Chihuahuan Desert, New Mexico, USA. Results show that vegetation green-up, the emergence of leaves, led to increased drag and surface aerodynamic sheltering and a reduction in us* and R magnitude and variability. We found that us* decreased from 20% to 5% of u* as the vegetation form drag and its sheltering effect increased. Similarly, the spatiotemporal variability of R was found to be linked directly to plant phenological phases. We conclude that drag partition schemes should incorporate seasonal vegetation change, via dynamic drag coefficients and/or R, to accurately predict the timing and magnitude of seasonal aeolian sediment fluxes.

29 Sep 2023

Enhancing Building Thermal Comfort: A Review of Phase Change Materials in Concrete

Abstract: The DoD accounts for over 1% of the country's total electricity consumption. However, DoD bases heavily rely on vulnerable commercial power grids, susceptible to disruptions from outdated infrastructure, weather-related incidents, and direct attacks. To enhance energy efficiency and resilience, it is imperative to address energy demand in buildings, especially heating and cooling. This study focuses on phase change materials (PCMs) incorporated into concrete to enhance thermal control and reduce energy consumption. Though PCMs have shown promise in heat transfer and energy storage applications, their integration into concrete faces challenges. Concerns include potential reduction in compressive strength, impacts on workability and setting time, effects on density and porosity, durability, and higher cost than traditional concrete. This report examines current obstacles hindering the use of PCMs in concrete and proposes opportunities for extensive research and application. By selecting appropriate PCMs and additives, comparable strength to control samples can be achieved. Moreover, specific techniques for incorporating PCMs into concrete demonstrate greater effectiveness. Embracing PCMs in concrete can significantly contribute to energy-efficient and resilient DoD installations.

28 Sep 2023

Incorporating Advanced Snow Microphysics and Lateral Transport into the Noah-Multiparameterization (Noah-MP) Land Surface Model

Abstract: The dynamic state of the land surface presents challenges and opportunities for military and civil operations in extreme cold environments. In particular, the effects of snow and frozen ground on Soldier and vehicle mobility are hard to overstate. Current authoritative weather and land models are run at global scales (i.e., dx > 10 km) and are of limited use at the Soldier scale (dx < 100 m). Here, we describe several snow physics upgrades made to the Noah-Multiparameterization (Noah-MP) community land surface model (LSM). These upgrades include a blowing snow overlay to simulate the lateral redistribution of snow by the wind and the addition of new prognostic snow microstructure variables, namely grain size and bond radius. These additions represent major upgrades to the snow component of the Noah-MP LSM because they incorporate processes and methods used in more specialized snow modeling frameworks. These upgrades are demonstrated in idealized and real-world applications. The test simulations were promising and show that the newly added snow physics replicate observed behavior with reasonable accuracy. We hope these upgrades facilitate ongoing and future research on characterizing the effects of the integrated snow and soil land surface in extreme cold environments at the tactical scale.

27 Sep 2023

Evaluation of Non-Destructive Testing (NDT) Methods for Wood Power Poles

Abstract: This technical report aims to test the effectiveness of several non-destructive testing (NDT) technologies on wood utility poles to detect deterioration. The project will assess commercially available devices using sound velocity and drilling resistance methods for in-field measurements. The goal is to extend the lifetime of wood poles, prevent unexpected failure, and enhance their in-service life beyond the current 75-year expectation. Despite the benefits of wood poles, it is difficult to obtain reliable deterioration metrics on in-service poles, which can lead to premature decommissioning or pole failure. NDT methods have been developed to replace labor-intensive methods, but none have been largely adopted in common practice. Therefore, creating a database of validated data would expedite adoption. Integrating precise and efficient wood utility pole NDT can increase installation energy resiliency and facility sustainment in a fiscally responsible way, ensuring high standards of delivery of services.

26 Sep 2023

During Nearshore Event Vegetation Gradation (DUNEVEG): Geospatial Tools for Automating Remote Vegetation Extraction

Abstract: Monitoring and modeling of coastal vegetation and ecosystems are major challenges, especially when considering environmental response to hazards, disturbances, and management activities. Remote sensing applications can provide alternatives and complementary approaches to the often costly and laborious field-based collection methods traditionally used for coastal ecosystem monitoring. New and improved sensors and data analysis techniques have become available, making remote sensing applications attractive for evaluation and potential use in monitoring coastal vegetation properties and ecosystem conditions and changes. This study involves the extraction of vegetation metrics from airborne lidar and hyperspectral imagery (HSI) collected by the US Army Corps of Engineers (USACE) National Coastal Mapping Program (NCMP) to quantify coastal dune vegetation characteristics. A custom geoprocessing toolbox and associated suite of tools were developed to allow inputs of common NCMP lidar and imagery products to help automate the workflow for extracting prioritized dune vegetation metrics in an efficient and repeatable way. This study advances existing coastal ecosystem knowledge and remote sensing techniques by developing new methodologies to classify, quantify, and estimate critical coastal vegetation metrics which will ultimately improve future estimates and predictions of nearshore dynamics and impacts from disturbance events.

26 Sep 2023

Microseira wollei (M. wollei) Blooms in Freshwater Ecosystems in Lake St. Clair (Michigan, USA)–Impacts and Possible Management Approaches

PURPOSE: The proliferation and shoreline accumulation of the filamentous biphasic cyanobacterium, Microseira wollei (M. wollei) (previously classified as Lyngbya wollei), have become an increasing problem in the Great Lakes, both for aesthetic reasons and its potential to harbor harmful bacteria and pathogens (Vijayavel et al. 2013). Occurrences have been reported and studies have also been conducted in the southeastern US where M. wollei has become a nuisance in recent years and is known to produce toxins (Hudon et al. 2014). Reports of M. wollei proliferations in the eastern US have been identified in the Manitoba lakes (Macbeth 2004), in Lake Erie from Maumee Bay (Bridgeman and Penamon 2010), in Lake St. Clair near Detroit (Vijayavel et al. 2013), and throughout the St Lawrence River (Vis et al. 2008; Lévesque et al. 2012). M. wollei has become a serious nuisance for marinas, public beaches, and lakefront property owners. In addition, M. wollei appears to have the ability to produce a wide range of toxins, but the conditions promoting their production, type, and concentration are poorly known (Hudon et al. 2014). Occurrences of large algal mats matching characteristics of M. wollei have been observed along the northwest shore and nearshore waters of the beach at Lake St. Clair dating back to 2010. To date, a comprehensive study detailing the potential impacts M. wollei has on freshwater ecosystems in the Great Lakes River, particularly Lake St. Clair is lacking. Further, management solutions are not well understood. This technical note (TN) reviews the potential causes of M. wollei blooms and their ecological impacts on aquatic systems and assesses the management options available to eliminate or minimize the impacts of these blooms.

26 Sep 2023

Linking the SEDLZJ Portable Standalone Library to the CMS Coastal Hydrodynamic Model

PURPOSE: This document describes the repackaging and linkage of the Sandia National Laboratories Environmental Fluid Dynamics Sediment Processes Code (SNL-EFDC-SEDZLJ), (Thanh et al. 2008). It was originally incorporated within a modified version of the US Environmental Protection Agency’s (USEPA) EFDC public-domain surface-water flow, sediment transport, and water-quality model developed by John Hamrick (Hamrick 1992) and its linkage to the ERDC-CHL-CMS hydrodynamic model. SNL-EFDC simulates flow and transport of sediment as bedload and suspended load. SNL-EFDC-SEDZLJ improves EFDC with updated sediment kinetics subroutines. Sediment erosion is calculated using data collected with a Sediment Erosion at Depth flume (SEDflume). SEDflume measures erosion rates as a function of shear stress and depth from relatively undisturbed cores taken directly from the sediment bed below the water body of interest. The use of SEDflume data provides more accurate sediment erosion rates that are directly input to the model.