14 Aug 2023

Technology Transfer: Converting Multizone HVAC Systems from Constant to Variable Volume

Abstract: This project promotes awareness and facilitates implementation of a low-cost controls retrofit for multizone air handling systems as an interim solution for energy efficiency that accrues savings while delaying system replacement. Implementation tools support technology evaluation and rapid implementation. Products include the following: fact sheet, technical note, pitch briefing, scoping guide, savings estimator, procurement package templates, commissioning guide, and on-line training. Multiple outreach activities occurred including presentations, journal articles, and contacting potentially interested parties.

11 Aug 2023

Dredged Material Can Benefit Submerged Aquatic Vegetation (SAV) Habitats

Purpose: This technical note (TN) was developed by the US Army Engineer Research and Development Center–Environmental Laboratory (ERDC-EL) to provide an overview of the ecosystem services delivered by submerged aquatic vegetation (SAV) to estuarine and coastal ecosystems and to describe potential methods for the beneficial use of dredged material (BUDM) to aid in SAV restoration. Although dredging tends to have a negative association with SAV habitats, BUDM may provide an opportunity to expand suitable SAV habitat to areas where depth is the primary limiting factor. Recent in situ observations have shown that SAV has opportunistically colonized several dredged-material placement sites. This TN provides context on BUDM for SAV habitat restoration to encourage increased strategic placement.

11 Aug 2023

International Workshop on Cold Regions Defense Infrastructure: 13–15 September 2022, Hanover, New Hampshire

Abstract: The Inaugural International Workshop on Cold Regions Defense Infrastructure united engineers and scientists of the US Department of Defense with defense representatives from the other nations comprising the International Cooperative Engagement Program for Polar Research (ICE-PPR): Canada, Denmark, Finland, Norway, Sweden, and New Zealand. Through the ICE-PPR Memorandum of Understanding, Project Arrangements (PAs) enable the seven nations to share measurements, models, and access to research sites and facilities. The goal of the workshop was to work as a coherent team to identify needs and develop PAs for three major topic areas: infrastructure, water/wastewater, and energy. Increasing interest in earth’s polar regions necessitates identifying capabilities and gaps for these critical mission-relevant topic areas.

10 Aug 2023

Sensitivity of Simulated Flaw-Height Estimates to Phased Array Scan Parameters

Abstract: Phased array ultrasonic testing (PAUT) is a nondestructive testing (NDT) technique for detecting and sizing flaws in welds. Estimates of flaw size are sensitive to a variety of PAUT scan parameters. In this study, estimates of flaw height are simulated using computer software. The sensitivity of these estimates to selected PAUT scan parameters is analyzed to identify those that have the greatest influence on estimates of flaw height. Understanding how varying different parameters within a phased array instrument affects the accuracy of flaw-height estimates helps to validate PAUT scan procedures and improve flaw-height estimates. For this research, a series of permutations on selected flaws were performed to see how certain parameters affect the accuracy in sizing flaw height. In addition, an analysis on how beam spread leads to flaw sizing inaccuracies was also conducted as part of this work.

9 Aug 2023

Repair of Corroded Steel Girders of Hydraulic Steel Structures (HSS) Using Fiber-Reinforced Polymers (FRP)

Abstract: Although steel hydraulic structures have a protective system to prevent corrosion, this type of deterioration will eventually occur due to the constant exposure to harsh environmental conditions. There are several techniques that can be implemented to repair corroded steel structural elements. This report presents a numerical study to evaluate the mechanical behavior of corroded steel girders used in hydraulic steel structures and to evaluate several carbon fiber–reinforced polymers (CFRP) layups to repair them. The girders were modeled as simply supported with four-point loading boundary conditions. The corrosion deterioration was modeled as loss in section as 10%, 25%, and 40%. The effectiveness of the deterioration was established based on the level of stresses at the steel compared with the undamaged condition after it is strengthened with CFRP. It was found that CFRP repair is more practical for reducing the stresses at the steel in the shear dominated zone if deterioration is below 25%. At the tensile dominated zone, CFRP is effective for reducing the stresses for deterioration below 40%.

8 Aug 2023

Evaluation of Structural and Operational Alternatives to Optimize the Distribution of Water and Sediment in the Passes of the Mississippi River

Abstract: Mississippi River shoaling and dredging processes in the vicinity of Head of Passes and in Southwest Pass were investigated. Existing rates of deposition and dredging were determined using near-daily eHydro bathymetric surveys, National Dredging Quality Management dredge operating data, and geospatial processing steps developed for this study. These surveys provide a means to characterize the highly dynamic and variable sedimentation patterns observed in the navigation channel. The HEC-6T one-dimensional numerical sedimentation model was used to evaluate possible modifications to the distribution of water and sediment in the Mississippi River near Head of Passes in an attempt to reduce shoaling in the navigation channel. The model was used to evaluate the effects of partial closures of several distributaries downstream from Venice and to evaluate the effects of channel widening and channel deepening adjacent to the Hopper Dredge Disposal Area at Head of Passes. In this study, various structural alternatives were compared to a base test that represented existing conditions. Sedimentation and dredging effects were projected 50 years into the future.

7 Aug 2023

Acoustic Doppler Current Profiler Study of Water and Sediment Movement through a Deep Scour Hole in the Lower Mississippi River

Abstract: A series of acoustic Doppler current profiler (ADCP) transects were collected through a deep scour hole at the bend near River Mile 60 on the Lower Mississippi River. The measurements were collected during both a low and a high flow. The ADCP results show a 3D flow field through the deep bend. The backscatter intensity of the ADCP measurements indicates the majority of the sediment remains close to the inside of the bed and high in the water column, with minimal concentrations at the bottom of the bend. These findings have implications for numerical sediment transport models, which tend to deposit material at the bottom of deep scour holes like the one in this study

7 Aug 2023

Soil-Moisture Estimation of Root Zone through Vegetation-Index-Based Evapotranspiration-Fraction and Soil-Properties (SERVES) User’s Manual Version 1.0

Purpose: The purpose of this user’s guide is to provide background methods and implementation guidance on the Soil-moisture Estimation of Root Zone through Vegetation-Index-Based Evapotranspiration-Fraction and Soil-Properties (SERVES) model (Pradhan 2019).

2 Aug 2023

Sustainable bank and channel stabilization techniques in arid southwest streams

Abstract: Channel stabilization and enhancement approaches take many different forms and are implemented using varying construction methods, materials, and techniques. The purpose of this study is to provide a comprehensive evaluation of sustainable streambank stabilization measures that are typically applied in arid southwest (SW) streams. This study was conducted at the request of the US Army Corps of Engineers (USACE), Albuquerque District (SPA), and USACE Headquarters. The document also provides rationale for evaluating bank and bed stabilization measures.

1 Aug 2023

Phase-Modulated Rice Model for Statistical Distributions of Complex Signals

Abstract: The basic Rice model is commonly used to describe complex signal statistics from randomly scattered waves. It correctly describes weak (Born) scattering, as well as fully saturated scattering, and smoothly interpolates between these extremes. However, the basic Rice model is unsuitable for situations involving scattering by random inhomogeneities spanning a broad range of spatial scales, as commonly occurs for sound scattering by turbulence in the atmospheric boundary layer and other scenarios. In such scenarios, the phase variations are often considerably stronger than those predicted by the basic Rice model. Therefore, the basic Rice model is extended to include a random modulation in the signal phase, which is attributable to the influence of the largest, most energetic inhomogeneities in the propagation medium. Various joint and marginal distributions for the complex signal statistics are derived to incorporate the phase-modulation effect. Approximations of the phase-modulated Rice model involving the Nakagami distribution for amplitude, and the wrapped normal and von Mises distributions for phase, are also developed and analyzed. The phase-modulated Rice model and various approximations are shown to greatly improve agreement with simulated data for sound propagation in the near-ground atmosphere.