29 Feb 2024

Computationally Efficient Modeling of Lightweight Expeditionary Airfield Surfacing Systems at Large Length Scales

Abstract: Expeditionary airfield matting systems are lightweight, portable surfaces that enable the rapid deployment of infrastructure to support aircraft operations. Individual matting components are assembled via interlocking joints to construct arrays that serve as temporary aircraft operating surfaces. The paper outlines the homogenization of the AM2 portable airfield matting system and its interlocking mechanisms to permit computationally efficient analyses toward understanding mechanisms that influence the global behavior of these arrays and underlying subgrade during aircraft maneuvers. An equivalent orthotropic two-dimensional continuum was developed from finite element analysis of a detailed three-dimensional model and its flexural behavior was validated against experimental data and solid finite element models. Interlocking joints were characterized using node-to-node connector elements based on subscale finite element studies. Both components were implemented into a full-scale model representative of a typical test section, and responses to static high tire pressure aircraft loads were analyzed over a soil foundation representing a California bearing ratio of 6%, yielding promising agreement with experimental data. Results of this study reveal an inherent coupling between load transfer, mat deflection, and near-surface subgrade stress with dependence on tire location, mat core shear flexibility, and joint stiffness.

29 Feb 2024

Analysis of Vegetation as Terrain: The “How” and “Why” of US Army Doctrine

Abstract: There is a significant knowledge gap for Army doctrine concerning civilian research scientists. A relatively small number of soldiers make the transition from warfighter to research and development at the basic and applied levels. That number is even less when considering former warfighters that have applied Army doctrine in an operational or advanced Army schooling environment. This special report is intended to focus solely on the Army’s current capabilities and doctrinally defined processes to analyze vegetation as an essential component of the natural terrain. The objective of this report is to review current Army doctrine related to analysis of the vegetated terrain; to explore currently leveraged tactics, techniques, and procedures (TTPs); and identify valuable geospatial resources as they apply to military planning. For ease to readers unfamiliar with US Army doctrine, much of the referenced material is directly presented herein as tables and figures throughout the document and appendices (e.g., data sources, product examples, and glossary).

29 Feb 2024

Waterway Engineering Applications of Automatic Identification System Data along the Mississippi River and at Lock Structures

Abstract: The USACE, St. Louis District, is responsible for maintaining navigation channels along with multiple lock and dam structures on the Mississippi River, a vital inland waterway that carries millions of tons of commodities every year. Understanding commercial vessel traffic patterns is fundamental to informing decisions about construction projects and to efforts to improve communication to mariners. Automatic Identification System (AIS) data provides time-stamped and geo-referenced vessel position reports for most commercial vessels operating in the District’s area of interest. This paper describes how AIS data has been successfully used by St. Louis District waterway managers to (1) prevent conflicts with the navigation industry by revealing active fleeting areas that were under consideration for the construction of river training structures; and (2) identify changes in vessel approaches to a lock structure under different river flow conditions, providing operational information that could be used in future navigation alerts to mariners. This paper concludes with a list of suggested best practices for waterways managers who want to start, or expand, their use of AIS data.

29 Feb 2024

Hurdles to Beneficial Use of Dredged Material: Root Cause Analysis

Purpose: This technical note (TN) summarizes high points of an internal review of US Army Corps of Engineers (USACE) dredging and dredged material management practices, specifically beneficial use of dredged material (BUDM), that USACE manages from various navigation channels and ports around the nation.

28 Feb 2024

Ecological Model to Evaluate Borrow Areas in the Lower Mississippi River

Abstract: An aquatic analysis of constructing borrow areas adjacent to the main line levees in the Lower Mississippi River was conducted as part of an Environmental Impact Statement for upgrading the levee system. A Habitat Suitability Index (HSI) regression model based on field collections was developed to predict fish species richness as a function of the morphometry and water quality of borrow areas. The HSI score was multiplied by acres of borrow areas created during construction to obtain habitat units (HUs) for each alternative indicating a substantial gain of fishery habitat in the floodplain. Environmental features identified by the model to increase fish species richness and overall habitat heterogeneity include the shape of the pit (e.g., bowl-shaped with deep water rather than long rectangular with shallower water), the availability of littoral areas for fish spawning and rearing, using best management practices such as tree screens and bank stabilization to lower turbidity, adding islands, and creating sinuous shorelines. The project results in an overall gain in aquatic habitat by creating permanent or semi-permanent water bodies on the floodplain that our research indicates may be occupied by at least 75 species of fish contributing to the overall biodiversity of the lower Mississippi River.

28 Feb 2024

Potential Lock Operations Management Application (LOMA) Hardware Installation Sites along the Ohio River to Improve Automatic Identification System (AIS) Reception and Transmit Range

Abstract: The purpose of this Coastal and Hydraulics Engineering technical note (CHETN) is to propose a list of candidate sites along the Ohio River for the installation of Automatic Identification System (AIS) shoreside towers within the US Army Corps of Engineers (USACE) Lock Operations Management Application (LOMA) program. The LOMA program manages a network of terrestrial (shoreside) AIS sites (Figure 1) and vessel-mounted AIS sites with receive and transmit capability. However, there are known limits to the reception and transmission areas served by existing shoreside towers (referred to as “coverage gaps”) along the Ohio River (DiJoseph et al. 2021). Parties interested in improving AIS coverage to enhance maritime domain awareness and navigational safety along the Ohio River may wish to pursue the installation of LOMA program hardware for this purpose.

28 Feb 2024

Characterising Earth Scent

Abstract: Rationale. Earth scent is the odour emitted from soils. This scent, primarily comprising the alcohols geosmin and 2-methylisoborneol (MIB), has not been fully characterised, but offers high potential for use as an environmental interrogation tool. Methodology. We utilised our field- based, solid-phase microextraction fibre method to test the hypothesis that soil activity and soil property variation can be detected in situ by comparing biogenic volatile emissions. Results. We eliminated sources of error utilising field-based sampling with these fibres, concluding that room temperature storage for up to 7 days is acceptable with minimal loss. Variation in individual fibre affinity for both compounds was higher than expected but no measured concentrations were observed to constitute outliers. Disturbance of minor soil volumes led to significantly higher emission of both compounds over background levels. Soil texture and soil cover had a significant effect on the emission of both compounds. Simulated rainfall, producing the characteristic odour known as petrichor, initiates elevated emission of geosmin. Background (undisturbed soil) concentrations of MIB were occasionally detectable during some sampling events, but geosmin concentrations in the air were always below detection limits without soil disturbance. Virtually all background and disturbed soil samples contained much higher concentrations of MIB compared to geosmin, but geosmin variation between replicates and experimental units was much lower. Discussion. Soil disturbance and soil property variation can be remotely detected using emission of volatile compounds. Correlating emission from the soil with respect to disturbance events and environmental properties could yield a powerful new tool for acquiring soil information.

22 Feb 2024

2D Fluorinated Graphene Oxide (FGO)-Polyethyleneimine (PEI) Based 3D Porous Nanoplatform for Effective Removal of Forever Toxic Chemicals, Pharmaceutical Toxins, and Waterborne Pathogens from Environmental Water Samples

Abstract: Although water is essential for life, as per the United Nations, around 2 billion people in this world lack access to safely managed drinking water services at home. Herein we report the development of a two-dimensional (2D) fluorinated graphene oxide (FGO) and polyethylenimine (PEI) based three-dimensional (3D) porous nanoplatform for the effective removal of polyfluoroalkyl substances (PFAS), pharmaceutical toxins, and waterborne pathogens from contaminated water. Experimental data show that the FGO-PEI based nanoplatform has an estimated adsorption capacity (qm) of ∼219 mg g−1 for perfluorononanoic acid (PFNA) and can be used for 99% removal of several short- and long-chain PFAS. A comparative PFNA capturing study using different types of nanoplatforms indicates that the qm value is in the order FGO-PEI > FGO > GO-PEI, which indicates that fluorophilic, electrostatic, and hydrophobic interactions play important roles for the removal of PFAS. Reported data show that the FGO-PEI based nanoplatform has a capability for 100% removal of moxifloxacin antibiotics with an estimated qm of ∼299 mg g−1. Furthermore, because the pore size of the nanoplatform is much smaller than the size of pathogens, it has a capability for 100% removal of Salmonella and Escherichia coli from water. Moreover, reported data show around 96% removal of PFAS, pharmaceutical toxins, and pathogens simultaneously from spiked river, lake, and tap water samples using the nanoplatform.

16 Feb 2024

Assessing the Genetic Diversity of Nymphoides peltata in the Native and Adventive Range Using Microsatellite Markers

Abstract: Nymphoides peltata (yellow floatingheart), native to Eurasia, is an invasive plant in the USA, where it grows in relatively isolated but widespread populations. The species is capable of sexual reproduction by seed and asexual reproduction through fragmentation. Although N. peltata is recognized as a noxious weed, little is known about its geographic region of origin or its dispersal mechanisms and relative amount of genetic variation in its adventive range. We conducted a genetic analysis of N. peltata by studying 68 localities across the native range and 47 localities in the adventive range, using microsatellite markers to determine genetic variability within and among populations, and to infer regions in the native range from which invasive plants originated. A large number of sites in the USA were genetically identical to one another, and there were two predominant multilocus allele phenotypes that were distributed in the northern and southern latitudes, respectively. Additional USA sites were similar to one of the predominant genetic profiles, with greater genetic diversity in southern populations. The genetically identical sites are consistent with asexual spread, potentially via anthropogenic mechanisms. Plants across the USA range were observed to produce viable seeds, and some genetic variation could be explained by sexual reproduction. All USA plants were more similar to plants in Europe than they were to plants in Asia, indicating that the plants likely were introduced originally from Europe. The existence of two genetic clusters and their similarity to plants in different parts of Europe constitute evidence for at least two N. peltata introductions into the USA.

16 Feb 2024

Deep Learning Methods for Omics Data Imputation

Abstract: One common problem in omics data analysis is missing values, which can arise due to various reasons, such as poor tissue quality and insufficient sample volumes. Instead of discarding missing values and related data, imputation approaches offer an alternative means of handling missing data. However, the imputation of missing omics data is a non-trivial task. Difficulties mainly come from high dimensionality, non-linear or non-monotonic relationships within features, technical variations introduced by sampling methods, sample heterogeneity, and the non-random missingness mechanism. Several advanced imputation methods, including deep learning-based methods, have been proposed to address these challenges. Due to its capability of modeling complex patterns and relationships in large and high-dimensional datasets, many researchers have adopted deep learning models to impute missing omics data. This review provides a comprehensive overview of the currently available deep learning-based methods for omics imputation from the perspective of deep generative model architectures such as autoencoder, variational autoencoder, generative adversarial networks, and Transformer, with an emphasis on multi-omics data imputation. In addition, this review also discusses the opportunities that deep learning brings and the challenges that it might face in this field.