18 Feb 2026

Infection Risk Assessment for Socially Structured Population Using Stochastic Microexposure Model

Abstract: Predicting infection outbreak dynamics within local microenvironments is a challenging task. Some methods assume smaller population pools and often lack the statistical power of inferences. Others are designed for larger population pools and cannot be downscaled to accommodate the details of microenvironments. Practicable infection risk assessment models should account for population size, geometry and occupancy of public places, behavioral and professional patterns of daily routines, and societal structure. This study is based on the stochastic microexposure model, which has been generalized to describe clustered populations. The methodology is demonstrated for a community of several thousand students on campus. The results indicate the social structure has the first order effect on the spread of the infection. Depending on the number, size, and degree of inner- and outer-cluster connections, the outbreak exhibits distinct durations, power, and multiple peaks of infection. Moreover, the contribution of different microenvironments to infection risk evolves during the course of the outbreak. Social structure plays a major role in infection spread and should be accounted for in risk prediction tools. The stochastic microexposure model accounts for the social structure of a population at multiple scales and can predict the dynamic contributions of different microenvironments to infection spread risks.

18 Feb 2026

Mesh Convergence Study of Adaptive Hydraulics (AdH) Version 5.9

Abstract: This report details performance and convergence tests of the Adaptive Hydraulics (AdH) v5.9 software suite on the Engineer Research and Development Center ONYX Cray X40/50 supercomputer. In particular, the performance of a recently developed monolithic model coupling AdH framework between the Richards equation for variable groundwater and surface water flows or for overland sloped conditions is studied. The effort is part of a quality assurance test of a recently restructured version of AdH. The report also includes a scalability analysis of AdH on a Cray system.

18 Feb 2026

Publications of the US Army Engineer Research and Development Center : Appendix J : FY25 (October 2024–September 2025)

Abstract: Each year, the US Army Engineer Research and Development Center (ERDC) publishes more than 200 reports through the Information Technology Laboratory’s Information Science and Knowledge Management (ISKM) Branch, the publishing authority for ERDC. Annually since 2017, ISKM has compiled a list of the previous fiscal year’s publications. This Appendix J to the original collection includes ERDC publications issued October 2024 through September 2025. The publications are grouped according to the technical laboratories or technical program for which they were prepared, and the preface includes procedures for obtaining ERDC reports. Through this compilation, online distribution, and physical collections, ISKM continues to support ERDC, the Army, and the nation.

18 Feb 2026

Modeling the Service Life of Temporary Airfield Operational Surfaces Under Multi-Pass Aircraft Trafficking

Abstract: Expeditionary Airfield (EAF) surfacing systems are designed to create temporary aircraft operating surfaces. Modeling the service life of EAF surfacing systems including the matting system, aircraft, and subgrade, has historically proven difficult, exacerbated by variability between systems and the multitude of mechanisms that can constitute failure. The study presented herein outlines the development and implementation of a performance modeling approach that includes a multi-scale scheme that accounts for local characteristics of the connection points of the EAF matting system, coupled to the global characteristics of the matting array to predict cyclic passes to failure. Finite element studies were conducted for an EAF surfacing system brickwork configuration subjected to aircraft strut loads over varying California Bearing Ratio (CBR) subgrades to calibrate a transfer function to full-scale trafficking experiments. The proposed framework is then used to predict the rate of subgrade deformation for additional lay patterns, which successfully ranked the performance of each relative to full-scale trafficking experiments. An approach is proposed to couple the rate of subgrade deformation with local finite element models to capture increasing joint damage as permanent deformation accumulates, and supplemented by a variable amplitude cycle counting and damage accumulation algorithm that yields reasonable agreement with full-scale experiments while capturing the transition in failure mechanisms at higher CBR values. The results of the study presented herein captures the propensity for end connector and subgrade failure over a range of subgrade CBRs and shows promise for a broader performance framework that can be extended to other EAF surfacing systems, aircraft types, and specific matting lay patterns.

18 Feb 2026

Civil Works Megaprojects: Cognitive Biases and Lessons for Effective Risk Mitigation

Abstract: U.S. Army Corps of Engineers (USACE) megaprojects are critical infrastructure investments that often experience cost overruns, schedule delays, and performance issues, with over 35 % of USACE dam structures rated in poor condition. This paper presents the first quantitative case study of past USACE Lock and Dam megaprojects—including the Charleroi, Chickamauga, Olmsted, Soo, and Montgomery projects —to identify patterns of risk mismanagement that contribute to these challenges. Using Bayesian methods and quantitative analysis on the risk registers of these projects, the study demonstrates that over-optimism in initial risk assessments, particularly the underestimation of risk likelihoods, can diminish the effectiveness of subsequent mitigation efforts by 25 % on average. The analysis also finds that risk managers tend to prioritize mitigation for risks where their confidence in assessment is highest, leaving higher-uncertainty risks less addressed. Based on these findings, the paper offers evidence-based recommendations for implementing structured risk governance frameworks, such as reference-class forecasting and external risk validation. This study advances project management knowledge by providing the first quantitative evidence of cognitive biases shaping risk register practices in civil works megaprojects. Incorporating such insights into future risk assessment and decision support methods can support critical infrastructure management and performance.

17 Feb 2026

Advancing Multi-Scale Wave Modeling: Global and Coastal Applications During the 2022 Atlantic Hurricane Season

Abstract: Using the six-month hurricane season of 2022 as a case study and the spectral wave model WAVEWATCH III, this effort shows that wave parameters produced via a variable-resolution global mesh (5–30 km) agree with a diverse array of validating observational datasets at a level comparable to that of a constant-resolution mesh (3 km) that is six times more costly to run. The optimized variable-resolution, unstructured triangular mesh is faithful to land geometry and wave transformation gradients while relaxing focus in deeper regions where gradients are typically less pronounced. Wave parameters measured via satellite altimetry, stationary buoy networks, and drifting buoys are employed to demonstrate not only a substantial increase in performance over a coarse, constant-resolution grid (40 km), with RMSE reduced from 0.28 m to 0.14 m and Correlation Coefficient (CC) improved from 0.92 to 0.98 overall, but also a comparable level of performance to that of a mesh that has undergone a full convergence analysis. Performance comparisons isolated to shallow regions and near cyclonic storms highlight the importance of resolving relevant geometries. For nearshore data, RMSE improves from 0.29 m to 0.13 m and CC from 0.89 to 0.98; in shallow regions, RMSE from 0.29 m to 0.15 m and CC from 0.88 to 0.97; and under cyclonic conditions, RMSE from 0.62 m to 0.35 m and CC from 0.93 to 0.98. Wave model results using the variable-resolution mesh were further analyzed to provide a detailed summary of the wave climate, including wind-wave and swell partitions, over the six-month study period in the study area.

13 Feb 2026

Morphology-Driven Electromagnetic Shielding Performance of Graphitic Nanoparticles in Segregated Polypropylene Nanocomposites via Electromagnetic Melt Processing

Abstract: Electromagnetic melt-processing has emerged as an innovative and energy-efficient strategy for the structuring of thermoplastic nanocomposites. In this study, polypropylene (PP)-based TPNCs were fabricated using different grades of graphitic carbon nanoparticles to yield electrical conductivity and electromagnetic interference shielding effectiveness. The applied structuring methodology consists of a multiscale processing strategy that combines high-energy ball milling of polymer micro-pellets and CNPs, formulated powder compaction into green bodies, and EM-driven localized heating to produce the TPNCs. This enables the formation of highly segregated, percolated conductive networks at ultra-low filler loadings. The percolation threshold values for green bodies were significantly dependent on CNP morphology, ranging from approximately 0.50 wt% for low-aspect-ratio graphene nanoplatelets to around 1.0 wt% for medium-aspect-ratio carbon nanotubes. Upon EM melt-processing, due to viscoelastic deformation of CNP networks, the resulting threshold values of the structured TPNCs were approximately 0.73 wt%, 0.50 wt%, and 0.74 wt% for low, medium, and high aspect ratios, respectively. High-aspect-ratio CNTs, despite exhibiting greater structural defects, achieved the highest EMI SE of 19.7 dB/mm at 10 wt%, demonstrating that morphology dominates over graphitic crystallinity in governing transport properties and electromagnetic performance. Statistical modeling via response surface methodology confirmed the predictive significance of the CNP morphology and the concentration responses. This work underscores the critical influence of filler architecture and EM-induced structuring in enabling a novel, scalable platform for multifunctional polymer nanocomposites with enhanced electromagnetic shielding capabilities, offering promise for next-generation aerospace, electronics, automotive, and defense applications.

13 Feb 2026

Standalone Color-Based Bathymetry Over 10 Years at Duck (NC, USA) from Optical Satellite Imagery and Wave Breaking Analysis

Abstract: Coastal hazard forecasting and morphological modeling rely on having accurate and up-to-date nearshore bathymetry. Traditional methods provide high precision but are expensive, complex to deploy, and only cover limited areas, leaving many coastal regions unmapped or under surveyed. In this context, Satellite-Derived Bathymetry provides a more accessible and scalable alternative, enabling frequent and global observations of the nearshore zone. This study applies the color-based log-band ratio method to extract nearshore bathymetry at Duck, North Carolina, a highly dynamic environment with a wide range of turbidity values and wave breaking extents. The log-band ratio method is an empirical approach for estimating shallow-water depths from multispectral satellite imagery which relies on the natural attenuation of light in water column, where the ratio of two spectral bands is logarithmically related to water depth. Unlike traditional SDB approaches, this method relies only on nearshore in situ wave height data, using satellite-detected breaking positions and breaker height-to-depth ratio as depth calibration points. Additionally, an automated approach is used to select images where the green/blue band penetrates sufficiently into the water to retrieve bathymetry avoiding the subjectivity of traditional manual selection. The method is validated through alongshore median- and profile-based assessments, yielding a median RMSE of ∼60 cm. Sensitivity tests on key parameters, including the breaker height-to-depth ratio and the calibration time window, demonstrate that a constant breaker height-to-depth ratio provides reliable results and that a significant number of calibration points is necessary for accurate bathymetry retrieval. This approach retrieves instant bathymetries and allows for the extraction of bathymetry evolution over time, with 90 bathymetry maps available over the 10-year period due to the very high resolution and 2-day revisit VEN𝜇S satellite and the 10-m/5-day Sentinel-2 mission. The method is transferable to other optical satellites such as Landsat, although it should be applied with caution, enabling long-term nearshore bathymetry monitoring from the 1980s to the present.

13 Feb 2026

Evaluating Freshwater Mussel Sampling Methodologies Using a Simulation Model

Abstract: Field surveys form the basis of many research efforts and are the foundation for estimates of population size and density that inform conservation and management practices for imperiled species. As a result, evaluating the performance of different survey methods across a range of conditions that may be encountered in the field can increase understanding of the time and effort that may be required to ensure that survey results are sufficiently accurate and reliable for conservation goals. We used a spatially explicit agent-based model to simulate four commonly used freshwater mussel field survey methodologies: simple random sampling (SRS), transect random sampling (TRS), adaptive cluster sampling (ACS), and qualitative timed searches (QTS) to investigate the influence of sampling method, spatial distribution, and mussel density on the performance (i.e., accuracy, precision, and detection rate) of survey techniques. Our analysis suggests that mussel density, spatial distribution, and sampling effort influence sampling accuracy, precision, and species detection for all sampling methods. QTS produces highly variable catch-per-unit-effort (CPUE) metrics when mussels are dense and/or clustered, indicating the technique may be unreliable as a proxy for density. Quantitative methods like SRS and TRS may be well-suited for estimating population characteristics, but a high level of effort may be needed to obtain reasonable accuracy when mussels occur at low densities. ACS may be more efficient for mussels at low densities, but it can be challenging to plan for the level of effort required to complete an ACS protocol. Designing an ecological survey requires careful consideration of research objectives and available resources. Future research may consider the performance of qualitative and quantitative surveys in combination as a means of overcoming some of the practical challenges of applying individual survey methods.

12 Feb 2026

Numerical Study of Submergence-Induced Forces on a Maintenance Bridge

Abstract: The US Army Engineer Research and Development Center–Coastal and Hydraulics Laboratory conducted a numerical study for a proposed maintenance bridge over the Trinity River in downtown Fort Worth, Texas, that will be submerged in flood conditions. The purpose of this study was to determine the hydrodynamic loads on the structure. The study found that, due to a combination of peak velocities and water depth, a return period of 500 yr generates the largest drag forces, while the higher depth and discharge of the standard project flood generate larger lift forces. Two flow structures were observed with shallow submergence: The first resulted in a jet parallel to the deck with a recirculation extending from railing to railing and the second resulted in a plunging jet over the deck with smaller but stronger recirculation. These patterns resulted in significantly different loads on the structure. The study analyzed the bridge’s deck slope to the flow as a possible variable affecting the loads. Observed changes related mostly to the flow pattern predicted for different flow configurations. Finally, it was observed that an open railing provides the best possible conditions in terms of loading; therefore, minimizing the frontal area of the railing is recommended.