31 Mar 2025

Effects of Thermal Modification on the Flexure Properties, Fracture Energy, and Hardness of Western Hemlock

Abstract: This study investigates the effect of thermal modification on the flexural properties, transverse fracture energy, and hardness of western hemlock. Flexure tests on specimens featuring longitudinal and transverse grains showed that thermal modification at 167 °C leads to less statistical variability compared to unmodified samples. Additionally, thermal modification leads to a decrease in the transverse flexural strength. On the other hand, the fracture and Janka hardness tests revealed a more pronounced brittleness of the thermally modified samples. The total mode I fracture energy of modified single-edge notch bending samples was about 47% lower for radial–longitudinal systems and 60% lower for tangential–longitudinal systems. Similarly, the average Janka hardness in the tangential and transverse planes was 8.5% and 9.4% lower in the modified specimens, respectively. The results presented in this work show that thermal modification can have a significant effect on the fracturing behavior of west-ern hemlock and its energy dissipation capabilities. For design, this must be taken into serious consideration as these properties significantly influence the damage tolerance of this wood in the presence of stress concentrations such as those induced in bolted joints and cut outs. Fracture energy and hardness are also strongly correlated to ballistic performance.

31 Mar 2025

USACE Relief Wells for Dams and Levees: History and Current Practice

Abstract: The purpose of this study was to review relief well practices within the United States Army Corps of Engineers (USACE). A literature review was performed on the history and use of relief wells relief and the state of practice within the USACE. As part of this study, a survey about relief well use and maintenance practice was prepared and distributed to selected Districts containing a large number of relief wells to determine their standard operating procedures for using those wells and to learn the history of their use. Responses obtained from these Districts were tabulated and classified according to the subject categories requested. Research needs and tools were requested as part of the survey, and a large portion of the responses indicated that there is an important need for research into biofouling prevention and remediation. Finally, a laboratory experiment was performed on several commercial-off-the-shelf sensors to measure effluent flow remotely. The results of the experiment showed that remote sensing of relief well flow is viable. It was found that pore pressures could be used to measure the relief well flows over a wide range of flow rates and with an error of 10 percent or less on average. Ultrasonic sensors also performed well during testing, with an average error of 10 percent or less.

27 Mar 2025

Toward a Method to Predict Thermo-Mechanical Properties of High-Strength Concrete Placements

Abstract: In this article, the merits of a thermo-mechanical framework to estimate properties of high-strength concrete are evaluated for potential standardization as a test method. Previous work conducted by the authors was summarized to show the individual advancements toward development of a laboratory testing framework. Most notably, laboratory-based curing protocols have been shown to produce temperature profiles that were similar to mass placements and achieving peak temperatures that were within 2°C of peak temperatures recorded in a mass high-strength concrete placement. Additionally, current testing methods to determine thermo-mechanical properties of mass concrete placements were reviewed, and a clear disconnect was noticed between methods that are predictive as well as a direct measure of mechanical properties. Based on this review of literature and the advancements summarized by the authors, a testing framework is proposed that takes the first steps toward filling this gap in literature of creating a predictive testing protocol that is also a direct measurement of mechanical properties.

21 Mar 2025

Engineering With Nature: Integrating Plant Communities into Engineering Practices. A Guidance Manual

Abstract: Applying native plant communities in environmental engineering practices can profoundly enhance the establishment and sustainment of natural ecosystems, which is imperative for the success of healthy habitats and the wildlife communities they support. The objective of this manual is to stimulate interest in applying native plants in a wide variety of settings, including inland, upland, coastal, riparian, and grassland. The information presented in this manual illustrates natural plant communities and sustainable strategies using native vegetation. This manual discusses the application of vegetation in US Army Corps of Engineers (USACE) projects. Additional case studies incorporate Engineering With Nature® (EWN®) principles into the design and development of existing infrastructural facilities within a military installation. Specifically, the manual identifies desirable plant species suitable for propagation in various states based on historic plant communities and ecological composition and lists invasive species to avoid with suggested native alternatives. Further, it discusses the use of native vegetation in biotechnical applications. Intended users are USACE districts, local, state, and federal agencies, contractors (specialists), and other users (generalists) engaged in EWN projects. Finally, the publication helps practitioners think creatively about using native plant species before, during, and after project design phases.

21 Mar 2025

Cultural Landscape Management Plan for Mare Island Naval Cemetery, California

Abstract: This project was undertaken to provide the US Department of Veterans Affairs National Cemetery Administration with a cultural landscape manage-ment plan for Mare Island Naval Cemetery. The approximately 2.5-acre cemetery is located in Vallejo, California, and contains more than 900 burials. Mare Island Naval Cemetery is part of the Mare Island Naval Ship-yard historic district, which was listed concurrently on the National Register of Historic Places and as a National Historic Landmark in 1975. The US Army Engineer Research and Development Center, Construction Engineering Research Laboratory (ERDC-CERL) was tasked with writing a cultural landscape management plan for Mare Island Naval Cemetery. Based upon the findings of the historic landscape inventory. Treatment recommendations were made to rehabilitate the historic landscape as well as to provide a sustainable plant list for the cemetery.

19 Mar 2025

Peptide Display for Rare Earth Element Binding

Abstract: Rare earth elements (REEs) are metals that are indispensable to the function of many advanced systems and materials. The supply chain of REEs is heavily dependent on foreign sources and supply shortages are a major concern to the US government. Biological recovery approaches could be an economically feasible approach to recover REEs from unconventional or secondary sources. The objective of this project was to express a lanthanide-binding tag, with an affinity for adsorption of REEs, on the surface of the biomining bacterium, Acidithiobacillus ferrooxidans. This was to be accomplished using synthetic biology tools. The initial cloning steps were performed in Escherichia coli, since techniques are well established in this strain. Using a peptide display approach, several DNA constructs with the binding tag were designed that were regulated by constitutive or inducible promoters and cloned into plasmids that replicate in E. coli and A. ferrooxidans. All plasmids were observed to be unstable or lethal in E. coli, exhibiting sequence rearrangements or deletion of the designed construct. Conjugation between E. coli and A. ferrooxidans and subsequent REE binding assays were thus not possible due to the absence of a structurally and functionally intact plasmid.

13 Mar 2025

Seasonality of Solute Flux and Water Source Chemistry in a Coastal Glacierized Watershed Undergoing Rapid Change: Wolverine Glacier Watershed, Alaska

Abstract: As glaciers rapidly lose mass, the tight coupling between glaciers and downstream ecosystems results in widespread impacts on global hydrologic and biogeochemical cycling. Knowledge of seasonally changing hydrologic processes and solute sources and signatures is limited. We conducted a broad water sampling campaign to understand the present-day partitioning of water sources and associated solutes in Alaska’s Wolverine Glacier watershed. We established a relationship between electrical conductivity and streamflow at the watershed outlet dividing the melt season into four hydroclimatic periods. Across hydroclimatic periods, we observed a shift in nonglacial source waters from snowmelt-dominated overland and shallow subsurface flow paths to deeper groundwater flow paths. We also observed the shift from a low- to high-efficiency subglacial drainage network and the associated flushing of water stored subglacially with higher solute loads. We used calcium from watershed outlet samples to estimate solute fluxes for each hydroclimatic period across two melt seasons. Between 40% and 55% of Ca2+ export occurred during the late season rainy period. Partitioning of the melt season coupled with a characterization of the chemical makeup and magnitude of solute export provides new insight into a rapidly changing watershed and creates a framework to quantify and predict changes to solute fluxes.

12 Mar 2025

Old River Control Low Sill Structure: Monitoring and Performance

Abstract: The Old River Low Sill Structure (ORLSS) is located approximately 25 mi south of Vidalia, LA, and is part of the Old River Control Complex. The structure is founded on steel piles and is a 566-foot-long concrete structure constructed in 1959. The structure resembles a dam with 11, 44-foot-wide gates to prevent migration of the Mississippi River’s current course to a hydraulically shorter course down the Atchafalaya River. A re-analysis was undertaken by the US Army Engineer Research and Development Center to investigate the current level of stability and the potential for adjusting the operating limitations placed on the structure because of damage during the 1973 flood. The investigation was performed by reviewing the design and post-design stability analyses, analyzing performance data, and performing an updated stability analysis. The stability analysis was performed with monitoring data that spanned several decades. Using historic monitoring data in the stability analysis, with a wide range of loading conditions, it was shown that uplift conditions were not as severe as previously considered. Performance data coupled with the stability analysis show that the structural performance supports the current operating conditions.

12 Mar 2025

Reading the Ground: Understanding the Response of Bioelectric Microbes to Anthropogenic Compounds in Soil Based Terrestrial Microbial Fuel Cells

Abstract: Electrogenic bacteria produce power in soil based terrestrial microbial fuel cells (tMFCs) by growing on electrodes and transferring electrons released from the breakdown of substrates. The direction and magnitude of voltage production is hypothesized to be dependent on the available substrates. A sensor technology was developed for compounds indicative of anthropological activity by exposing tMFCs to gasoline, petroleum, 2,4-dinitrotoluene, fertilizer, and urea. A machine learning classifier was trained to identify compounds based on the voltage patterns. After 5 to 10 days, the mean voltage stabilized (+/- 0.5 mV). After the entire incubation, voltage ranged from -59.1 mV to 631.8 mV, with the tMFCs containing urea and gasoline producing the highest (624 mV) and lowest (-9 mV) average voltage, respectively. The machine learning algorithm effectively discerned between gasoline, urea, and fertilizer with greater than 94% accuracy, demonstrating that this technology could be successfully operated as an environmental sensor for change detection.

12 Mar 2025

Collaborative Development of Natural and Nature-Based Solutions for Coastal Resiliency in the Arctic and Adjacent Regions: A Workshop

The workshop “Collaborative Development of Natural and Nature-Based Solutions for Coastal Resiliency in the Arctic and Adjacent Regions” was held in Reston, Virginia, October 24–25, 2023. The objective was to assemble diverse international partners in a hybrid in-person and virtual setting to focus on the viability of applying Nature-Based Solutions (NBS) to solve engineering challenges in the Arctic and similar cold region locations. The goals of the two-day workshop were to share recent efforts implementing NBS to mitigate coastal hazards such as flooding and erosion in northern high latitude settings and identify requirements and develop a robust program of activities to advance this work at national, regional, and local levels. This workshop report documents the presentations and discussion and summarizes key needs and recommendations for future engagement identified by speakers and workshop participants.