20 Aug 2020

PUBLICATION NOTICE: A Proposed Ecosystem Services Analysis Framework for the U.S. Army Corps of Engineers

Abstract: Ecosystem goods and services (EGS) have been promoted as a way to effectively examine tradeoffs and improve communication of project-related environmental outcomes in terms of human well-being. This document proposes a framework to inform the development of any future guidance to U.S. Army Corps of Engineers (USACE) District planners for projecting changes in EGS from proposed civil works activities. The framework offers an analytical and communications approach for incorporating EGS in USACE decision-support processes. The core of the framework is a conceptual model that establishes a series of causal relationships that link management actions to EGS benefits/damages, applying economic concepts in both monetary and non-monetary benefit relevant indicators. The six-step planning process is used to demonstrate how the EGS framework might be integrated into existing analytic approaches and modified to fit different levels of resource availability and decision contexts. A hypothetical case study is used to demonstrate analytic techniques. The framework is compatible with goals to create a single decision-support document covering National Environmental Policy Act requirements and planning objectives when comparing project alternatives. The example is intended to generally illustrate the use of EGS in any type of program planning or project evaluation.

20 Aug 2020

PUBLICATION NOTICE: Concept for Artificial Freezing of Sea Ice at Winter Quarters Bay, Antarctica

ABSTRACT:  McMurdo Station serves as a major research and logistics hub for the United States Antarctic Program (USAP). Adjacent to the Station is Winter Quarters Bay (WQB), where vessels dock to unload cargo and fuel. The ice pier at McMurdo is essential for this annual vessel resupply but represents a failure potential, occasionally breaking up during or immediately after vessel operations. This study aimed to determine the feasibility of using thermopiles, a passive cooling technology, to artificially freeze seawater to “grow” the existing WQB bottomfast-ice edge so that ships can dock directly against it. Finite element simulations using modeling-parameter assumptions indicate that each row of thermopiles can grow a frozen wall to a depth of 9 m in about a month if installed on 1 July with an initial sea-ice thickness of 1 m and a thermopile spacing of 1.5 m. For our simulation scenarios, we approximate that it would take 255 to 820 days to complete a 40 m by 140 m wedge of bottomfast ice. The estimated cost ranges from about $600,000 to $1,600,000. These results serve as a preliminary feasibility study of successfully using thermopiles for generating a direct docking bottomfast-ice wharf at McMurdo.

20 Aug 2020

PUBLICATION NOTICE: Sediment Sorting by Hopper Dredging and Pump-Out Operations: Sampling Methods and Analysis

Abstract: Hopper dredging operations for beach and nearshore placement typically include periods of overflow, which produces some degree of separation between the size fractions of the dredged sediment. The degree of separation and the controlling factors are presently poorly known. This report focuses on laboratory experiments aimed at determining (1) suitable sampling methods on a dredge, (2) composite sampling techniques to reduce analysis cost, (3) associated sampling intervals to achieve suitable sediment representation of a hopper load, and (4) a hydraulic means of sample splitting. Results showed that no statistical difference exists among the three methods used to sample the hopper weir overflow. The method used to sample deposited hopper sediment identified a bias in the percent fines that resulted from flow sheltering. Further, it was found that composited samples were able to quantify the concentration and percent fines accurately, although an analytical data experiment showed that the accuracy of a composited sample is dependent on the sampling intervals. The accuracy of the fines and concentration from a hydraulic sample splitter was found to be dependent on median grain size, with fine sediment being evenly distributed and coarser sediment increasing the error in concentration and grain size distribution.

20 Aug 2020

PUBLICATION NOTICE: Site-Specific Case Studies for Determining Ground Snow Loads in the United States

ABSTRACT:  The U.S. Army Cold Regions Research and Engineering Laboratory (CRREL) has mapped ground snow loads for much of the United States. In some areas where extreme local variations preclude mapping on a national scale, instead of loads, “CS” is used to indicate that Case Studies are needed. This report and the accompanying spreadsheet, which contains the 15,104-station CRREL ground snow load database, provide the information needed to conduct Case Studies. When the latitude, longitude, and elevation of a site of interest are provided, the spreadsheet tabulates data available in the vicinity and generates plots that relate ground snow loads nearby to elevation. With this information, the ground snow load at the site of interest can be determined. This report uses 10 examples to illustrate the methodology and provides our answer and the comments we generate for each of these Case Studies and for 16 additional sites of interest, 8 of which have their answers “disguised” for practice purposes. CRREL has conducted over 1000 Case Studies upon request. Practicing structural engineers were involved in over 250 of them to verify that this methodology is ready to transfer to the design profession.

20 Aug 2020

PUBLICATION NOTICE: Understanding State-of-the-Art Material Classification through Deep Visualization

Abstract: Neural networks (NNs) excel at solving several complex, non-linear problems in the area of supervised learning. A prominent application of these networks is image classification. Numerous improvements over the last few decades have improved the capability of these image classifiers. However, neural networks are still a black-box for solving image classification and other sophisticated tasks. A number of experiments conducted look into exactly how neural networks solve these complex problems. This paper dismantles the neural network solution, incorporating convolution layers, of a specific material classifier. Several techniques are utilized to investigate the solution to this problem. These techniques look at specifically which pixels contribute to the decision made by the NN as well as a look at each neuron’s contribution to the decision. The purpose of this investigation is to understand the decision-making process of the NN and to use this knowledge to suggest improvements to the material classification algorithm.

11 Aug 2020

PUBLICATION NOTICE: Post-Project Monitoring of a Navigation Solution in a Dynamic Coastal Environment, Smith Island, Maryland: Year One of Post-Project Monitoring

Abstract: In 2018, jetties and a sill were constructed by the US Army Corps of Engineers (USACE) adjacent to the Sheep Pen Gut Federal Channel at Rhodes Point, Smith Island, Maryland. These navigation improvements were constructed under Section 107 of the Continuing Authorities Program. Material dredged for construction of the navigation structures and realignment of the channel were used to restore degraded marsh. Following construction and dredging, 1 year of post-project monitoring was performed to evaluate the performance of navigation improvements with respect to the prevention of shoaling within the Sheep Pen Gut channel, shoreline changes, and impacts to submerged aquatic vegetation (SAV). Given the short period of record after the completion of the navigation improvements, it was difficult to draw conclusions regarding stability of the channel, structures, and shoreline. Therefore, this report documents methodology and baseline conditions for monitoring, except for SAV, which was found to be potentially impacted by construction. A second year of monitoring was funded by the USACE Regional Sediment Management Program for fiscal year 2020. Findings can be used to inform plan formulation and design for USACE navigation projects by illuminating considerations for placement of structures to prevent shoaling and by informing SAV management decisions.

11 Aug 2020

PUBLICATION NOTICE: The Urban Ground-to-Ground Radio-Frequency Channel: Measurement and Modeling in the Ultrahigh Frequency Band

ABSTRACT:  Ground-to-ground radio communication and sensing within the urban environment is challenging because line of sight between transmitter and receiver is rarely available. Therefore, radio links are often critically reliant on reflection and scattering from built structures. Little is known about the scattering strength of different buildings or whether such differences are important to the urban ground-to-ground channel. We tested the hypotheses that (1) diffuse scattering from built structures significantly impacts the urban channel and (2) scattering strength of urban structures varies with surface roughness and materials.  We tested these hypotheses by measuring urban channels in Concord, New Hampshire, and Boston, Massachusetts, and via channel-modeling efforts with three-dimensional representations of the urban environment. Direct comparison between measured and modeled channels suggest that both of these hypotheses are true. Further, it appears that ray-tracing approaches underestimate the complexity of urban channels because these approaches lack the physical processes to correctly assess the power incident on and scattered from built structures. We developed a radio-geospatial model that better accounts for incident power on both directly visible and occluded buildings and show that our model predictions com-pare more favorably with measured channels than those channels predicted via typical ray-tracing approaches.

11 Aug 2020

PUBLICATION NOTICE: Army Installation Makerspaces in the Morale, Welfare, and Recreation (MWR) Operational Environment: A Business Case Analysis

Abstract:  This work demonstrated the implementation of makerspaces, collaborative workspaces that provide hands-on learning to help prepare the future workforce with critical 21st century applied-technology skills. Researchers from the U.S. Army Engineer Research and Development Center, Construction Engineering Research Laboratory (ERDC-CERL) enhanced and evaluated the pre-existing makerspace at Fort Bliss, Texas to demonstrate the value of a makerspace within the military Morale, Welfare, and Recreation (MWR) environment. The 8-month pilot demonstration, conducted from May to December 2018, focused on investigating program characteristics such as usage trends, optimal locations, equipment, and personnel access. Results from the demonstration indicated that enhanced makerspaces with high quality equipment had a positive Soldier impact. The business case analysis determined that the Fort Bliss Makerspace fits the criteria of, met the 15% cost-to-revenue ratio threshold for, and can operate successfully as, a Category Type A (Mission Sustaining) program asset.

11 Aug 2020

PUBLICATION NOTICE: Development of Expedient Ultra-High Molecular Weight Aircraft Arresting System Panel Installation Procedures

Abstract: The US Army Engineer Research and Development Center conducted an evaluation of different procedures to install ultra-high molecular weight polyethylene panels beneath pendant-based aircraft arresting systems (AAS). Currently employed techniques were modified or new techniques were developed to increase productivity and installation accuracy, aid in system constructability, and reduce logistical concerns when compared to AAS requirements and pavement repair guidance. Procedures for both asphalt concrete and portland cement concrete surfaced runway pavement were evaluated. The field evaluation was conducted from July to August 2013 at the Silver Flag Training Site, Tyndall Air Force Base, FL. The evaluation consisted of timing various procedures using a six- to eight-man installation crew. Equipment and supplies currently in Air Force inventories were preferred, but outside items were not prohibited if performance gains could be achieved and the new items were deployable using typical military cargo aircraft. Required work tasks were organized and grouped together to efficiently complete the panel installation work within multiple short-term runway closure windows without any long-term closures greater than 12 hours to allow for aircraft operations during the installation process. This report summarizes the timed field trials and the pertinent conclusions based on the results. Recommendations for implementation including additional equipment, supplies, and personnel needs are provided.

11 Aug 2020

PUBLICATION NOTICE: Autonomous QUerying And PATHogen Threat Agent Sensor System (AQUA PATH): Monitoring Source Waters with Geospatially Wirelessly Networked Distributed Sensing Systems

Abstract: Contaminants serve as health risks to recreational water, potable water, and marine life that result in undocumented effects on population exposure. In many areas of the world, the concern lies in contaminated drinking water, which would immediately effect social and economic order. As research advances for innovative solutions, the deployment of automated systems for source water monitoring could reduce the risk of exposure. Water quality monitoring typically involves sample collection and analyses that are performed in a laboratory setting. These results are normally presented after an 18−48 hr period. This report details the prototyped Autonomous QUerying And PATHogen threat agent sensor (AQUA PATH) geoenabled system that is able to detect the presence/absence of pathogenic bacteria indicators in source waters and report these values in the field, in less than 30 minutes. The AQUA PATH system establishes rapid field data collection and reports assessment of source waters bacterial loads at near shore inner coastal locations, which makes a leap forward compared to current presence/absence tests standards established by the EPA.