• An Elastic-Inelastic Model and Embedded Bounce-Back Control for Layered Printing with Cementitious Materials

    Abstract: This paper presents a finite-deformation model for extrusion-based layered printing with cementitious materials. The evolution of mechanical properties as the printed material cures and stiffens results in nonphysical reduction in the magnitude of elastic strains when standard constitutive models are employed. This elastic recovery of the printing induced deformation contradicts the experimentally observed behavior of the printed cementitious materials that harden at a nearly-frozen deformed state. A thermodynamically motivated constraint on the evolution of elastic strains is imposed on the constitutive model to remedy the nonphysical bounce-back effect. An algorithm that is based on a strain-projection technique for the elastic part of deformation is developed that complements the inelastic response given by the Drucker–Prager model. It is then embedded in a finite strain finite element framework for the modeling and simulation of cure hardening and inelastic response of the early age cementitious materials. A ghost mesh method is proposed for continuous layer-wise printing of the material without the need for intermittent mesh generation technique or adaptive remeshing methods. The model is validated via comparison with experimental data and representative test cases are presented that investigate the mathematical and computational attributes of the proposed model.
  • Levees and Dams at Fort Riley, Kansas, and the Response to the 1951 Flood

    Abstract: This project provides a historic context and inventory for the levees and dams constructed at Fort Riley, Kansas. The purpose of this historic con-text and inventory is to determine the levees and dams’ eligibility for listing in the National Register of Historic Places (NRHP). Determinations of eligibility to the NRHP are then made based on the significance of the levees and dams and the degree to which they retain their integrity for conveying that significance. The authors inventoried and evaluated three levees and two lake dams on the installation. Based on the historic context and inventory, researchers for this project have determined that none of the levees and dams are eligible for the inclusion in the NRHP nor was there enough evidence for a noncontiguous historic district at Fort Riley.
  • Public virtual orientation announced for Mississippi River study

    The U.S. Army Corps of Engineers, New Orleans District has announced a virtual public orientation
  • USACE announces virtual BBSEER Project Delivery Team Meeting January 17, 2024

    The U.S. Army Corps of Engineers Jacksonville District invites Project Delivery Team members, stakeholders, partners, and members of the public to attend a virtual Project Delivery Team (PDT) Meeting for the Biscayne Bay and Southeastern Everglades Ecosystem Restoration (BBSEER) Project study on Wednesday, January 17, 2024, from 1 p.m. to 4 p.m.
  • Hartwell, Russell, Thurmond Lakes no longer in drought level 2 operations

    SAVANNAH, Ga. – The U.S. Army Corps of Engineers, Savannah District, announces Hartwell, Richard B. Russell and J. Strom Thurmond Lakes have come out of drought level 2 and are now back in drought level 1 operations due to the recent rain over the Savannah River System Basin.
  • Temporary closure of shower buildings and comfort stations at Lake Ouachita

    VICKSBURG, Miss. – In advance of the upcoming inclement weather, Lake Ouachita is temporarily closing or partially closing shower buildings and comfort stations across the project beginning today. These facilities are not built to sustain prolonged extreme low temperatures. Facilities are expected to be reopened on 18 January 2024. We apologize for any inconvenience.
  • Weather prompts temporary closures at Saylorville Lake

    Due to forecasted inclement weather, the U.S. Army Corps of Engineers, Rock Island District, will temporarily close the portion of NW 78th Ave. that crosses over Saylorville Lake Dam starting at 8 p.m. tonight. The roadway will be closed from the Iowa National Guard Armory entrance to the Saylorville Lake Visitor Center entrance. All Saylorville Lake recreation areas will also be closed to ensure the safety of staff and visitors. The roadway and recreation areas will reopen when conditions improve, and staff are able to safely clear the areas. For up-to-date information on area closures, follow us on social media at www.facebook.com/SaylorvilleLake, or contact the Saylorville Lake project office at 515-276-4656.
  • Classifying and Benchmarking High-Entropy Alloys and Associated Materials for Electrocatalysis: A Brief Review of Best Practices

    Abstract: In light of the immense compositional diversity of high-entropy materials (HEMs) recently reported (e.g., high-entropy chalcogenides, perovskites, ceramics, etc.) and the relatively amorphous definition of High-Entropy, it is imperative that consistent material classification and benchmarking practices be employed to facilitate comparison between reported figures of merit. In this opinion, an updated form of the numerical high entropy definition is reviewed, which renders a universal entropy metric applicable to high-entropy alloys and emerging HEMs alike. Analytical methods to verify the existence of a solid-solution microstructure, elucidate atomic valence states, and probe atomic disorder are discussed with literature examples to facilitate the physical classification of HEMs. Electrocatalytic benchmarking is discussed in the context of water splitting reactions and best practices are reviewed for determining the electrocatalytically active surface area, reaction overpotential, and electrocatalyst stability.
  • UPDATE: Temporary full road closure of Highway 178 across Bull Shoals Dam

    The U.S. Army Corps of Engineers is rescheduling the full road closure for Highway 178 across Bull Shoals Dam to 7 a.m. Jan. 18 until 5 p.m. Jan. 19, to deploy and remove equipment used to perform maintenance on the dam. The original closure scheduled for Jan. 16-18 is rescheduled because of the weather.