9 Sep 2025

Damage Parameters and Crack Morphology in High Strength Concrete BBR9 Under Dynamic Uniaxial Compressive Loading: An Experimental Study

Abstract: There has been significant growth in the use of high-strength concrete in structures designed to withstand extreme events. Continuum damage mechanics has been utilized to develop constitutive models that can capture the damage evolution in concrete materials under such conditions. This study is aimed at investigating the damage initiation, progression, and morphology of HSC-Baseline Basic Research Mixture 9 when subjected to dynamic uniaxial compressive loading. A Kolsky compression bar system was implemented to introduce distinct damage states in the HSC-BBR9 specimens. The partially damaged specimens were tested to quantify their residual mechanical properties. Accordingly, stiffness-based and strength-based constitutive damage parameters were adopted to propose an indirect quantification of the damage state based on the deterioration of mechanical properties. The X-ray micro-computed tomography technique was utilized to extract measurements of 3D crack networks that provide a direct quantification of the damage state based on microstructural evidence. The results demonstrated the HSC-BBR9 material can maintain its residual mechanical properties into the post-peak regime. In the initial stages of damage, stiffness and strength deteriorate at a proportional rate; however, as damage accumulates, the rate of stiffness degradation increases. Correlations between constitutive damage parameters and 3D crack measurements were established.

8 Sep 2025

US Army Corps of Engineers Aquatic Restoration Monitoring for Ecosystem Recovery (ARMER) Network

Abstract: Long-term, high-quality ecosystem restoration monitoring is essential to achieve recovery and maximize restoration investments. However, there are many challenges associated with restoration monitoring that inhibit effective collection, storage and management, communication, and utilization of ecosystem recovery information. A nationwide monitoring network of restoration and reference sites is needed to generate high-quality, replicated datasets to address large-scale ecosystem restoration challenges. The US Army Corps of Engineers (USACE) makes significant annual investments in ecosystem restoration projects and monitoring for adaptive management under their aquatic ecosystem restoration mission, and thus, is uniquely positioned to lead the development of an ecosystem recovery monitoring network. Investments in large-scale, long-term data collection and management would allow USACE to (1) improve data consistency and data replication to reduce uncertainty in ecological recovery assessments, (2) demonstrate the socioecological benefits of restoration to better inform future restoration investments, and (3) improve the USACE’s ability to publicly communicate returns on investments and the nationwide value of aquatic ecosystem restoration. This report details a roadmap for how USACE could leverage aquatic ecosystem restoration investments to operationalize the USACE Aquatic Restoration Monitoring for Ecosystem Recovery (ARMER) Network and advance the science of aquatic ecosystem restoration.

4 Sep 2025

The Edge of Crisis: Discovery of Young of Year Black Carp Mylopharyngodon piceus (Richardson, 1846) in the Lower Mississippi River

Abstract: Understanding changes in the status of invasive species is important to managers in order to prevent or minimize impacts to native communities. Out of the four invasive carp imported to the U.S. from Eastern Asia, black carp Mylopharyngodon piceus have been generally overlooked due to the difficulty in capturing these fish even using targeted efforts. Because of this, limited resources have been channeled towards managing this species. Concerns over the expansion of black carp have been expressed, but direct evidence of reproduction in U.S. waters was lacking until young of year black carp were caught in tributaries of the Middle Mississippi River in 2015. This remained the known extent of the naturalized invasion until fish community surveys conducted in the fall of 2022 and 2023 documented young of year black carp in three oxbow lakes connected to the mainstem Lower Mississippi River. These collections provide evidence for increased population growth and exhibit expanding threats to the diverse mussel communities native to the Lower Mississippi River basin.

3 Sep 2025

Optimal Transport-Based Full-Waveform Inversion for Shallow Seismic Data

Abstract: Full-waveform inversion is widely used to reconstruct subsurface properties at different geologic scales. For shallow land applications using surface waves, a lack of information on the source wavelet, dispersion, and presence of higher modes increases the nonlinearity of the inverse problem. The inversion can become more challenging with the presence of near-surface complexities associated with scattering, attenuation, and high-contrast variations in the elastic parameters. Compared with the least-squares formulation, GSOT provides a more convex misfit function and reduces dependence on the accuracy of the initial model. Although a few field-data applications have shown the potential and benefits of using GSOT-based FWI with body waves, there are limited real applications of the inversion with a GSOT misfit function for NS characterization. Despite considerable effort with blind benchmark tests in exploration seismology, typically synthetic FWI examples for NS applications are demonstrated through an “inverse crime” approach. Synthetic FWI examples performed compare the performance of LS- and GSOT-based FWI with more realistic scenarios. We demonstrate the GSOT misfit function improves the initial 1D velocity models and guides the updates toward the actual subsurface properties. This enables the recovery of higher-mode Rayleigh waves and reconstruction of the cavity with better precision.

3 Sep 2025

Acute Toxicity of Carbon Nanotubes, Carbon Nanodots, and Cell-Penetrating Peptides to Freshwater Cyanobacteria

Abstract: Synthetic non-metallic nanoparticles have been explored to treat harmful algal blooms, but their strain-specific algicidal activities have been rarely investigated. Three batches of CNDs were prepared in-house using glucose or chloroform and methanol as the substrate and one batch of single-walled CNTs. The axenic laboratory culture of each cyanobacterial strain was exposed to an NMNP at two dosage levels for 48 h, followed by measurement of five endpoints. The endpoints were optical density at 680 nm for chlorophyll-a estimation, OD at 750 nm for cell density, instantaneous pigment fluorescence emission after being excited with 450 nm blue light for chlorophyll-a or 620 nm red light for phycocyanin, and quantum yield for photosynthesis efficiency of photosystem II. The results indicate the acute toxicity was strain-, NMNP type-, dosage-, and endpoint-dependent. The two benthic strains were more resistant to NMNP treatment. SWCNTs and fraction A14 of CND-G were more toxic than CND-G and CND-C/M. The CPP was the least toxic. The high dose generally caused more severe impairment. OD750 and OD680 were more sensitive and QY was the least sensitive. The strain dependence of toxicity suggested the potential application of these NMNPs as a target-specific tool for mitigating harmful cyanobacterial blooms.

3 Sep 2025

Three-Dimensional Simulation of Finite-Strain Debonding Using Immersed Meshes

Abstract: We propose a method for modeling interfacial damage and debonding under quasi-static loads using immersed meshes in 3D at finite strains. This is an extension of our previous work on an immersed variational multiscale discontinuous Galerkin method in 2D. The variational approach remains the same, but transitioning from 2D to 3D introduces significant complications in the computational geometry aspects. The immersed VMDG method is a stabilized interface formulation derived using variational multiscale ideas to apply discontinuous Galerkin treatment to the interface while employing a continuous Galerkin approximation elsewhere. Key benefits are the variationally derived stabilization terms that evolve during deformation and are free of user-defined parameters. Also, the transition from perfect bond to damage behavior at the interface is handled naturally by incorporating an interfacial gap variable governed by a yield criterion and a flow rule. To support 3D simulations, we introduce algorithms for integrating cut elements, forming interface segments, and computing the VMDG stabilization tensor. Cut-element integration is performed using voxel-based moment-fitting integration to avoid the robustness issues associated with using mesh Booleans and tetrahedral integration cells. Several numerical examples are presented to demonstrate the robustness, efficiency, and range of applicability of the method.

3 Sep 2025

Hydrodynamics in the Morganza Floodway and Atchafalaya Basin, Report 5: Phase 5

Abstract: The Morganza Floodway and Atchafalaya Basin, located in Louisiana west of the Mississippi River, were evaluated using a 2D Adaptive Hydraulics model. Prior to this study, Phase 1 and 2 model studies showed that the Morganza Floodway may not be able to pass the Project Design Flood discharge of 600,000 cubic feet per second due to levee overtopping. Phase 3 and 4 model studies help to further the understanding of how flood waters propagate throughout the floodway as well examined alternatives to increase the discharge capacity of the floodway. Phase 5 furthered the work completed in Phases 3 and 4 by exploring more alternatives to aid the Morganza Floodway in passing the Project Design Flood.

3 Sep 2025

Hydrodynamics in the Morganza Floodway and Atchafalaya Basin, Report 4: Phase 4

Abstract: The Morganza Floodway and Atchafalaya Basin, located in Louisiana, west of the Mississippi River, were evaluated using a two-dimensional Adaptive Hydraulics model. Prior to this study, Phase 1 and 2 model studies showed that the Morganza Floodway may not be able to pass the Project Design Flood discharge of 600,000 cfs due to levee overtopping. A Phase 3 model study helped to further the understanding of the effects of trees and vegetation on the flow capacity of the floodway. In Phase 4 of this study, changes in elevations through means of excavation as well as the cutting of rights-of-way (ROW) were examined to determine their effects on flow conveyance in the floodway.

3 Sep 2025

Exploring Burnt Area Delineation with Cross-Resolution Mapping: A Case Study of Very High and Medium-Resolution Data

Abstract: Remote sensing is essential for mapping and monitoring burnt areas. Integrating Very High-Resolution (VHR) data with medium-resolution datasets like Landsat and deep learning algorithms can enhance mapping accuracy. This study employs two deep learning algorithms, UNET and Gated Recurrent Unit (GRU), to classify burnt areas in the Bandipur Forest, Karnataka, India. We explore using VHR imagery with limited samples to train models on Landsat imagery for burnt area delineation. Four models were analyzed:(a) custom UNET with Landsat labels, (b) custom UNET with PlanetScope-labeled data on Landsat, (c) custom UNET-GRU with Landsat labels, and (d) custom UNET-GRU with PlanetScope-labeled data on Landsat. Custom UNET with Landsat labels achieved the best performance, excelling in precision (0.89), accuracy (0.98), and segmentation quality (Mean IOU: 0.65, Dice Coefficient: 0.78). Using PlanetScope labels resulted in slightly lower performance, but its high recall (0.87 for UNET-GRU) demonstrating its potential for identifying positive instances. In the study, we highlight the potential and limitations of integrating VHR with medium-resolution satellite data for burnt area delineation using deep learning.

2 Sep 2025

Morphology Control in Waterborne Polyurethane Dispersion Nanocomposites Through Tailored Structure, Formulation, and Processing

Abstract: Waterborne polyurethane dispersions (PUDs) have garnered increasing interest in recent years due to the growing demand for environmentally friendly materials. The unique phase-separated morphologies exhibited in PUD films and coatings provide opportunities for directing the distribution of functional additives and controlling properties. Although there has been extensive research on polyurethanes for several decades, the mechanisms underlying the PUD morphology formation are poorly understood. The morphologies are driven by interactions between hard segments (HS), and the process is further complicated by the presence of colloidal particles and the intricate interaction between the urethane/urea linkages and water. In this work, structure−property-processing relationships between HS content and structure, relative humidity, particle size, and the resulting dry film morphology of PUDs were determined in two diisocyanate systems: hexamethylene diisocyanate (HDI), a symmetric, flexible diisocyanate; and isophorone diisocyanate (IPDI), an asymmetric, sterically hindered cyclic diisocyanate. HDI-based films exhibited semicrystalline morphologies with HS superstructures that are sensitive to relative humidity. IPDI-based films displayed spherical coalescence-suppressed morphologies influenced by particle size and zeta potential. PUD compositions and processing conditions were controlled to produce nanocomposite films with an enhanced dispersion of nanoadditives.