5 May 2026

Carrying Capacity in Human-Environment Interactions: A Systematic Review

Abstract: The concept of carrying capacity has been applied broadly to various biological and social contexts. This article presents a systematic review of the carrying capacity literature as applied to human-occupied environments. The review evaluates underlying approaches and methods and explores the utility and limitations of the concept’s applications. Prominent tools and approaches identified include evaluation index systems, ecological footprint analysis, the Cifuentes method, multi-objective optimization, system dynamics, fuzzy mathematics, and remote sensing and geographical information systems. Our findings indicate that, despite its origins, carrying capacity research is rarely concerned with the survival of human communities; instead, it is often invoked to understand the implications of human population growth and urbanization on living and sufficiency standards. The majority of identified carrying capacity studies did not define a strict upper boundary, demonstrating the utility of carrying capacity as a rhetorical strategy to galvanize action before system degradation eliminates options. The concept of carrying capacity, when applied to human-managed and constructed environments, increasingly reflects socioeconomic factors and quality of life considerations, underscoring subjective social constraints and societal tolerance levels rather than physical limitations on population survival.

5 May 2026

Behavioral Responses of Silver Carp to Underwater Acoustic Deterrent Sounds

Abstract: Invasive carps continue to spread across the Mississippi River basin, posing significant ecological risk. Identifying technologies to slow their dispersal is critical. The use of sound has been proposed as a method to modify the behavior of Silver Carp Hypophthalmichthys molitrix, offering a nonstructural deterrent strategy. Silver Carp implanted with acoustic transmitters were released into earthen ponds equipped with telemetry arrays. The fish were exposed to a 30-min playback of three underwater sounds (chirp saw, chirp square, and 100- hp boat motor). Movement trajectories were analyzed using a two-state hidden Markov model to estimate the effects of environmental and experimental variables on fish behavior. The results of the hidden Markov model supported two behavioral states. State 1 was characterized by longer step lengths and greater directional persistence in turning angle, indicative of heighted activity. State 2 was defined by shorter step lengths and less directional persistence, suggesting reduced activity. Silver Carp that were exposed to the chirp square sound had an increased likelihood of entering state 1, whereas the 100-hp boat motor sound promoted transitions to state 2. Underwater sounds distinctly influenced the movement of Silver Carp in earthen ponds. The chirp square sound elicited heightened activity levels, demonstrating potential for use in acoustic deterrent applications. However, the response of Silver Carp to these sounds may be influenced by the size of the study environment or the absence of natural drivers of fish behavior, such as food or reproduction. This study contributes to the development of nonstructural, species-specific deterrent systems by identifying sounds that influence the behavior of invasive carps. The application of sound- based methods may play a critical role in integrated pest management strategies for invasive carps, potentially limiting their spread while minimizing effects on native species.

5 May 2026

Designing Sortable Guilds for Multispecies Selective Fish Passage

Abstract: The importance of connectivity for freshwater organisms is widely recognised, yet in-stream barriers associated with population declines and increased risk of extinction remain globally ubiquitous. Despite their negative consequences, these barriers can protect aquatic communities by limiting the spread of invasive species, leading to conflicting management goals in some regions. Selective fish passage is a solution for the conflicting goals of passing native, desirable species while restricting the spread of invasives. Approaches that can target groups of species sharing similar attributes (i.e. guilds) are likely to be more efficient than those that target species individually, particularly in taxonomically diverse systems. We explored the guild structure of 220 Great Lakes freshwater fishes based on morphological, phenological, physiological and behavioural attributes associated with passage and movement. We identified five distinct guilds as well as the attributes most important for defining these groupings: maximum total length, trophic level, relative eye size, spawning temperature, spawning season, presence/absence of ampullary electroreceptors and the presence/absence of hearing specialisations. The approaches outlined in this work can be generalised to enhance selective fish passage in aquatic ecosystems worldwide.

5 May 2026

Hierarchical Rule-Base Reduction-Based ANFIS with Online Optimization Through DDPG

Abstract: This article presents a comprehensive approach to designing and optimizing a hierarchical rule-base reduction-based adaptive-network-based fuzzy inference system (ANFIS) for symmetric linguistic variables. Specifically, the linguistic connected membership functions that underlie the ANFIS are defined, focusing on symmetrical inputs/outputs and jointly optimized trapezoid membership functions to reduce the number of training parameters. Further optimizations for the ANFIS were derived based on design assumptions, including training the membership functions on closed or single-sided domains. The optimal output membership weights based on mean square error optimization were also symbolically obtained. The online training of the ANFIS’s input/output membership functions was performed using the deep deterministic policy gradient (DDPG) algorithm. A simulated skid-steered vehicle was used to validate the approach and performed waypoint-to-waypoint path following. Experimental results using the Clearpath Jackal demonstrated that the ANFIS model converged quickly, typically within 6 to 10 episodes of training, from an initial mean absolute error (MAE) and root mean squared error (RMSE) of 0.88 and 1.02 m, respectively, to a final MAE and RMSE of 0.087 and 0.10 m. The results highlight the effectiveness of the ANFIS approach for vehicular robotics applications and suggest promising avenues for future research and development.

4 May 2026

Insight into the Photocatalytic Degradation Mechanism for “Forever Chemicals” PFNA by Reduced Graphene Oxide/WO3 Nanoflower Heterostructures

Abstract: Water contamination with “forever chemicals” like per- and polyfluoroalkyl substances (PFAS) poses significant toxicity to the environment. Since they are the most persistent synthetic chemicals that hardly degrade in the natural environment and are carcinogenic to humans, there is an urgent need to discover novel processes for destroying PFAS. Herein, we report on the design of a reduced graphene oxide (r-GO)/WO3 nanoflower (WO3-NF)-based heterostructure for harnessing 365 nm light-driven photocatalytic oxidation and reduction process toward the photocatalytic degradation of perfluorononanoic acid (PFNA). Moreover, reported data reveal that using an r-GO/WO3-NF heterostructure photocatalyst, 100% PFNA degradation and 14% defluorination can be achieved in the presence of isopropyl alcohol as the hydroxy radical (•OH) quencher or glucose as a hot hole (h+) quencher after exposure to 365 nm light for 22 h. A reported mechanistic study shows synergistic oxidation and reduction processes are vital for the complete degradation of PFNA, where the hydrated electron (eaq−) plays a key role as a reducing agent and h+ and •OH act as oxidation agents. Furthermore, the photocatalytic destruction mechanism study indicates that chain shortening via C−C bond breaking and defluorination via C−F bond breaking are major pathways for PFNA degradation. A wavelength-dependent study shows that only 22% degradation can be achieved after exposure to 532 nm light for 22 h, which is due to the lack of the formation of hydrated electrons (eaq−). The current study sheds light on the construction of the r-GO/WO3 NF heterojunction for the highly efficient degradation of PFAS.

4 May 2026

Impact of Vessel Operations on Navigation Channel Stability and the Broader Environment: Insights from a Workshop Held 4–5 September 2024

Abstract: Vessel operations in the US Army Corps of Engineers (USACE) portfolio of waterways create a range of environmental and navigation challenges. This report documents the proceedings of a workshop highlighting research and development (R&D) on vessel-related navigation channel stability and associated environmental impacts. Across 13 workshop presentations, three major themes emerged to guide future USACE R&D efforts: (1) the need for better data and standardized processing routines, (2) the need for a streamlined modeling framework that can simulate all relevant physical processes for vessel operation, and (3) the need for improved internal and external partnerships to better address vessel-related issues. Addressing these critical knowledge gaps will advance engineering practice associated with vessel operations in USACE waterways.

4 May 2026

Characterizing Lithium-Ion Battery Health and Mitigating Transportation and Recycling Hazards

Abstract: With the growing trend toward electric vehicle (EV) use, the demand for safe, efficient, and cost-effective energy storage grows increasingly crucial. The ability to effectively characterize battery health, transport and dispose of batteries safely, and mitigate the by-products of battery recycling are all important to reduce the risks of lithium-ion battery (LIB) usage throughout the battery’s life cycle. The transportation and disposal of LIBs present critical challenges and require stringent safety measures to mitigate risks effectively. Additionally, many recycling methods are less cost-effective or more environmentally harmful than mining new materials. This report describes the findings of a collaborative project between the University of Illinois Urbana-Champaign and US Army Engineer Research and Development Center, Construction Engineering Research Laboratory, to address these concerns and contribute to safer and more environmentally friendly transportation, recycling, and disposal of LIBs. The most common battery recycling techniques are investigated—pyrometallurgy, hydrometallurgy, and direct recycling—along with the environmental impact of these methods. The overall potential environmental impacts of LIB usage can be greatly improved through proper battery disposal. Addressing hazards at the battery level by enhancing the stability and cooling of batteries can simplify battery transportation and improve safety.

4 May 2026

Freshwater Wetland Carbon Flux Analysis Pertinent to the Net Emissions Analysis Tool Improvement: Method Development and Testing

Palustrine wetlands are ecosystems of interest due to their capacity to sequester large amounts of greenhouse gases. This field study in Washington and Idaho was conducted as proof of concept of methods for measuring carbon emissions in palustrine wetlands. The regions of Washington and Idaho were chosen as they span three different Environmental Protection Agency (EPA) Level 1 ecoregions in a relatively close geological area. Data were collected across all three ecoregions in an effort to detail the potential differences between palustrine wetlands within them. Carbon dioxide flux measurements were compared across two instruments: LICOR 8,100A and CIRAS-4. Supporting data related to vegetation and site characteristics were incorporated into the overall analyses. Results suggest that carbon dioxide flux varies in relation to several factors. Additional research will be required to inform the application of site-specific data which can improve the application of tools designed to quantify project scale estimates for net greenhouse gas emissions.

4 May 2026

Installation Access Control Technology at Redstone Arsenal: Biometric-Enabled Technology for Installation Entry

Abstract: A pair of biometric capabilities useful for access control were demonstrated at Redstone Arsenal to support installation modernization and the integration of smart infrastructure. This project addresses gap requirements outlined in the March 2020 report to Congress by the Assis-tant Secretary of the Army for Installations, Energy, and Environment (ASA IE&E), Army Report on Creating an Army Installations Test and Demonstration Program Using Commercial Technologies. The demonstration tracked the number of transactions completed at an access control point (ACP) lane using a facial recognition system and at a secure facility using a touchless fingerprint reader and facial recognition kiosk. The operational duration of the systems showed their robustness. Multiple cameras in the express lane system accurately identified vehicle occupants while minimizing traffic backups. The touchless fingerprint system installed at the secure facility was easy to use, and users preferred it, leading to it quickly surpassing the existing method.

4 May 2026

Erosion Test Database Reassessment with Application to Engineered Soils

Abstract: This report presents a reevaluation of the soil erosion property relation-ships and a reanalysis of the data with a specific focus on compacted and engineered fill materials. Reinterpretation first centered on describing the parametric space of the database in which the models’ ability to predict critical shear stress and the erodibility coefficient parameter have the greatest uncertainty. Second, this work considered the smaller subset of the dataset with only engineered fill and compacted materials. However, considering only this subset was not found to reduce significantly the uncertainty in predictive capability. We recommend additional work to expand the dataset, focusing on materials in conditions more representative of the compacted and aged soils present on many flood control infrastructure projects.