7 May 2026

Tribological Properties of Synthetic and Biosourced Lubricants Enhanced by Graphene and Its Derivatives: A Review

Abstract: This review explores the tribological properties of biosourced lubricants (biolubricants) enhanced by graphene (Gr) and its derivatives and hybrids. Friction and wear at mechanical interfaces are the primary causes of energy loss and machinery degradation, necessitating effective lubrication strategies. Traditional lubricants derived from mineral oils present environmental challenges, leading to an increased interest in biolubricants derived from plant oils and animal fats. Biolubricants offer high biodegradability, renewability, and low toxicity, positioning them as ecofriendly alternatives. This work extensively reviews the role of Gr-based nanoadditives in enhancing the lubrication properties of biolubricants. Gr with its exceptional physicomechanical properties has shown promise in reducing friction and wear. The review covers various Gr derivatives, including Gr oxide (GO) and reduced Gr oxide (r-GO), and their performance as lubrication additives. The discussion extends to Gr hybrids with metals, polymers, and other 2D materials, highlighting their synergistic effects on the tribological performance. The mechanisms through which these additives enhance lubrication, such as the formation of protective films and improved interactions between lubricants and tribopairs, are examined. Emphasis is placed on the environmental benefits and potential performance improvements of Gr-based biolubricants. Finally, by analyzing current research and technological trends, the paper outlines future prospects for optimizing lubricant formulations with Gr-based nanoadditives, aiming for more sustainable and efficient tribological applications.

7 May 2026

An All-Hazards Return on Investment (ROI) Model to Evaluate U.S. Army Installation Resilient Strategies

Abstract: The paper describes our project to develop, verify, and deploy an All-Hazards Return of Investment (ROI) model for the U.S. Army Engineer Research and Development Center (ERDC) to provide army installations with a decision support tool for evaluating strategies to make existing installation facilities more resilient. The need for increased resilience to extreme weather caused by climate change was required by U.S. code and DoD guidance, as well as an army strategic plan that stipulated an ROI model to evaluate relevant resilient strategies. During the project, the ERDC integrated the University of Arkansas designed model into a new army installation planning tool and expanded the scope to evaluate resilient options from climate to all hazards. Our methodology included research on policy, data sources, resilient options, and analytical techniques, along with stakeholder interviews and weekly meetings with installation planning tool developers. The ROI model uses standard risk analysis and engineering economics terms and analyzes potential installation hazards and resilient strategies using data in the installation planning tool. The ROI model calculates the expected net present cost without the resilient strategy, the expected net present cost with the resilient strategy, and ROI for each resilient strategy. The minimum viable product ROI model was formulated mathematically, coded in Python, verified using hazard scenarios, and provided to the ERDC for implementation.

6 May 2026

Two-Dimensional Thermal and Dynamical Strain in Landfast Sea Ice from InSAR: Results From a New Analytical Inverse Method and Field Observations

Abstract: Observing continuous strain in sea ice at geophysical scales of tens of meters to kilometers requires displacement measurements made with millimeter-scale precision. Satellite-based interferometric synthetic aperture radar (InSAR) provides such precise measurements of relative surface displacement over broad spatial areas at regular intervals and, unlike point displacement measurements, it allows confident delineation of continuously deforming regions. However, InSAR only captures the 1-D component of surface displacement parallel to a radar’s lines-of-sight. Additional analysis is required to translate between these 1-D observations and the horizontal or vertical displacements they arose from. Previous studies utilize an iterative inverse model to constrain estimates of horizontal surface displacement from InSAR. Here we build upon that work outlining a new analytical inverse modeling method for quantifying displacement and strain over continuous regions of sea ice and provide comparison between model results and independent displacement observations. We demonstrate the inverse method over both landfast and drifting ice along the Alaskan coastline. These intercomparisons highlight environments in which displacements inverted from interferograms may be used as an independent estimator of surface strain, as well as the potential for the outlined inverse methods to be used in conjunction with other observing methods.

6 May 2026

Economic Valuation and Natural Resource Damage Assessment Methods at Myakka River State Park, Florida

Abstract: The growing population and distribution of invasive wild pigs across vulnerable ecological communities has emerged as a significant issue, and there is not a standardized ecological-economic framework to precisely measure and value the impact of wild pigs to natural resources. The FY24 research presented here is year four of a 4-year research plan to develop a user-friendly ecological-economic framework for rapid assessment and valuation of wild pig damage to wetlands. Building off the findings from research conducted at Somerville Lake, Texas, and Richard K. Yancey Wildlife Management Area, Louisiana, this FY24 research took place at Myakka River State Park, Florida. Research objectives for FY24 included adapting the ecological-economic framework to a different landscape type, refining and broadening the artificial intelligence–based economic valuation approach by valuing a variety of natural communities, and improving the setup of the before-after-control-impact study design estimating damage reduction after a targeted control effort. Across the study area, we estimated that the benefits provided by the natural communities lost to wild pigs over a 1-year period were $273,525 (80% confidence interval: $72.684 and $920.883), and an aerial gunning control effort produced an estimated 685% return on investment in avoided losses 4 weeks postmanagement.

5 May 2026

Uptake and Elimination of Per-and Polyfluoroalkyl Substances in Earthworms Exposed to Spiked Artificial Soil or Aqueous Medium

Abstract: We investigated the accumulation of per-and polyfluoroalkyl substances (PFAS) in earthworms (Eisenia andrei). Uptake kinetics and bioaccumulation factors (BAFs) were determined using a mixture of 16 PFAS by exposing earthworms to spiked artificial soil for up to 28 days. Two treatments were used, with the low treatment targeting environmentally relevant concentrations. The concentrations of PFAS remained relatively unchanged during the exposures and statistically significant rates of uptake were estimated for most individual PFAS. For the 0.01 mg/kg treatment (target concentration of each PFAS), steady state was reached for all PFAS except perfluoroheptanoic acid, perfluorohexanesulfonic acid (PFHxS), perfluorooctanesulfonic acid (PFOS), perfluorotetradecanoic acid (PFTeDA), and perfluorotridecanoic acid. For the 0.01 mg/kg treatment, bioaccumulation factors (BAF; kg/kg-dry wt) ranged from 4–49 for most PFAS but were higher for PFHxS (72), PFTeDA (271), and perfluoroundecanoic acid (299). Organic carbon–normalized BAFs were within the range of published values. The BAF values increased with increasing length of the alkyl chain for perfluoroalkyl carboxylic acids (PFCAs), but not for perfluoroalkyl sulfonic acids (PFSAs). Uptake rates and BAFs were lower for the 1 mg/kg treatment, typically by over one order of magnitude, likely because of sublethal physiological impairment. Fast and steep decreases in tissue concentrations of PFAS occurred when earthworms were transferred to clean soil, even for long chain PFAS, agreeing overall with previous reports. However, measured elimination rates were faster than predicted from the uptake experiments and the causes remain unknown. Bioaccumulation of PFAS was also investigated in exposures to aqueous medium for up to 7 days to derive bioconcentration factors (BCFs). Comparison of BCFs and BAFs suggests that uptake from soil may have higher relevance than dermal uptake from porewater for long-chain PFCAs and PFSAs.

5 May 2026

Permafrost and Rain Influence Summer Hydrologic Flowpaths in Boreal Catchments

Abstract: Flowpaths of water through catchments influence water quality and flow regimes of streams. Depths of dominant flowpaths respond to variation in climate and catchment characteristics, such as topography, vegetation, and soil type. In high‐latitude regions, the depth and spatial extent of permafrost influences catchment hydrology, and thawing permafrost might change sources and pathways of water supplying solutes and flow to streams. We estimated contributions of precipitation, soil water, and groundwater flowpaths to streams during the open‐water period after snowmelt by applying a Bayesian mixing model to 4–6 years of observed solute concentrations in five catchments of boreal Alaska. The relative contribution of groundwater to streams varied from 12% to 82% across catchments and years and declined as spatial extent of permafrost increased from 25% to 58% across catchments, indicating potential for increased infiltration and drainage as permafrost thaws. Temporal patterns in precipitation also influenced flowpaths. The mean annual contribution of precipitation to streamflow increased in years with more rain. Groundwater contribution increased, on average, in years with few large storms, suggesting deepening flows due to seasonal ground thaw or loss of shallow water to evapotranspiration. In contrast, groundwater contributed less in years when large storms delivered most of the year's rain in late summer or autumn. Overall, spatial and temporal variation in relative flowpath contributions to streams suggest that permafrost thaw will deepen flowpaths, but increasing precipitation expected in high‐latitude regions under warming climate might obscure this effect by routing water via shallow flowpaths following large storms.

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.