13 Sep 2023

Cold Impacts on Vehicle Electrical Systems: Developing a Baseline for Cold Testing Military Vehicles

Abstract: Low temperatures can significantly affect vehicle operation. While many of the effects, like increased fluid viscosity and decreased battery capacity, are well documented, the impacts on the electrical system as a whole are not. The objective of this study was to investigate the impacts of temperature on the electrical systems of select military vehicles and to develop a baseline for future testing. A High Mobility Multipurpose Wheeled Vehicle (HMMWV), a Heavy Expanded Mobility Tactical Truck (HEMTT), and a four-person diesel Polaris MRZR D4 were subjected to 15°C, 0°C, and −15°C temperatures while the loads on the battery and alternator were monitored. The HMMWV and MRZR were able to start on the first try for all tests. They both showed a slight increase in vehicle load current draw from the alternator as temperatures decreased. Future testing with more iterations and at lower temperatures will help identify clearer trends and improve testing procedures. As the Army becomes more reliant on electronic systems, it is becoming increasingly important that we understand how various climates will impact them.

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.

7 Nov 2022

Cold Regions Vehicle Start: Next-Generation Lithium-Ion Battery Technologies for Stryker Vehicles

Abstract: Operating vehicles in extremely cold environments is a significant problem for not only the public but also the military. The Department of Defense has encountered issues when trying to reliably cold start large, heavy-duty military vehicles, specifically the M1126 Stryker Combat Vehicle, in cold regions. As noted in previous work, the issue stems from the current battery technology’s limited temperature range. This current project utilized the protocol established in the previous phase to evaluate next-generation lithium-ion battery technologies for use in cold regions. Selected battery technologies met necessary military specifications for use in large military combat vehicles and were evaluated using a mechanical load system developed in previous work to simulate the starting of a Stryker engine. This work also evaluated the performance of the existing battery technology of a Stryker under Alaskan winter temperatures, which will verify the accuracy of the simulated cold room testing on the mechanical load system. The results of the tests showed that while the system was able to reliably operate down to −20°C, the battery management system encountered challenges at the lower end of the temperature range. This technology has a potential to reliably support cold regions operations but needs further evaluation.

1 Nov 2022

Snow-Covered Region Improvements to a Support Vector Machine-Based Semi-Automated Land Cover Mapping Decision Support Tool

Abstract: This work builds on the original semi-automated land cover mapping algorithm and quantifies improvements to class accuracy, analyzes the results, and conducts a more in-depth accuracy assessment in conjunction with test sites and the National Land Cover Database (NLCD). This algorithm uses support vector machines trained on data collected across the continental United States to generate a pre-trained model for inclusion into a decision support tool within ArcGIS Pro. Version 2 includes an additional snow cover class and accounts for snow cover effects within the other land cover classes. Overall accuracy across the continental United States for Version 2 is 75% on snow-covered pixels and 69% on snow-free pixels, versus 16% and 66% for Version 1. However, combining the “crop” and “low vegetation” classes improves these values to 86% for snow and 83% for snow-free, compared to 19% and 83% for Version 1. This merging is justified by their spectral similarity, the difference between crop and low vegetation falling closer to land use than land cover. The Version 2 tool is built into a Python-based ArcGIS toolbox, allowing users to leverage the pre-trained model—along with image splitting and parallel processing techniques—for their land cover type map generation needs.

22 Nov 2021

Artificial Ground Freezing Using Solar-Powered Thermosyphons

Abstract: Thermosyphons are an artificial ground-freezing technique that has been used to stabilize permafrost since the 1960s. The largest engineered structure that uses thermosyphons to maintain frozen ground is the Trans Alaska Pipeline, and it has over 124,000 thermosyphons along its approximately 1300 km route. In passive mode, thermosyphons extract heat from the soil and transfer it to the environment when the air temperature is colder than the ground temperature. This passive technology can promote ground cooling during cold winter months. To address the growing need for maintaining frozen ground as air temperatures increase, we investigated a solar-powered refrigeration unit that could operate a thermosyphon (nonpassive) during temperatures above freezing. Our tests showed that energy generated from the solar array can operate the refrigeration unit and activate the hybrid thermosyphon to artificially cool the soil when air temperatures are above freezing. This technology can be used to expand the application of thermosyphon technology to freeze ground or maintain permafrost, particularly in locations with limited access to line power.

5 Oct 2021

Installation Resilience in Cold Regions Using Energy Storage Systems

Abstract: Electrical energy storage (EES) has emerged as a key enabler for access to electricity in remote environments and in those environments where other external factors challenge access to reliable electricity. In cold climates, energy storage technologies face challenging conditions that can inhibit their performance and utility to provide electricity. Use of available energy storage technologies has the potential to improve Army installation resilience by providing more consistent and reliable power to critical infrastructure and, potentially, to broader infrastructure and operations. Sustainable power, whether for long durations under normal operating conditions or for enhancing operational resilience, improves an installation’s ability to maintain continuity of operations for both on- and off-installation missions. Therefore, this work assesses the maturity of energy storage technologies to provide energy stability for Army installations in cold regions, especially to meet critical power demands. The in-formation summarized in this technical report provides a reference for considering various energy storage technologies to support specific applications at Army installations, especially those installations in cold regions.

4 May 2021

Ice Fog Monitoring Near Fairbanks, AK

ABSTRACT:  Ice fog events, which occur during the Arctic winter, result in greatly decreased visibility and can lead to an increase of ice on roadways, aircraft, and airfields. The Fairbanks area is known for ice fog conditions, and previous studies have shown these events to be associated with moisture released from local power generation. Despite the identified originating mechanism of ice fog, there remains a need to quantify the environmental conditions controlling its origination, intensity, and spatial extent. This investigation focused on developing innovative methods of identifying and characterizing the environmental conditions that lead to ice fog formation near Fort Wainwright, Alaska. Preliminary data collected from December 2019 to March 2020 suggest that ice fog events occurred with temperatures below −34°C, up to 74% of the time ice fog emanated from the power generation facility, and at least 95% of ice particles during ice fog events were solid droxtals with diameters ranging from 7 to 50 µm. This report documents the need for frequent and detailed observations of the meteorological conditions in combination with photographic and ice particle observations. Datasets from these observations capture the environmental complexity and the impacts from energy generation in extremely cold weather conditions.

1 Dec 2020

Snow-Covered Obstacles’ Effect on Vehicle Mobility

ABSTRACT:  The Mobility in Complex Environments project used unmanned aerial systems (UAS) to identify obstacles and to provide path planning in forward operational locations. The UAS were equipped with remote-sensing devices, such as photogrammetry and lidar, to identify obstacles. The path-planning algorithms incorporated the detected obstacles to then identify the fastest and safest vehicle routes. Future algorithms should incorporate vehicle characteristics as each type of vehicle will perform differently over a given obstacle, resulting in distinctive optimal paths. This study explored the effect of snow-covered obstacles on dynamic vehicle response. Vehicle tests used an instrumented HMMWV (high mobility multipurpose wheeled vehicle) driven over obstacles with and without snow cover. Tests showed a 45% reduction in normal force variation and a 43% reduction in body acceleration associated with a 14.5 cm snow cover. To predict vehicle body acceleration and normal force response, we developed two quarter-car models: rigid terrain and deformable snow terrain quarter-car models. The simple quarter models provided reasonable agreement with the vehicle test data. We also used the models to analyze the effects of vehicle parameters, such as ground pressure, to understand the effect of snow cover on vehicle response.

1 Sep 2020

PUBLICATION NOTICE: Seasonal Effects on Vehicle Mobility: High-Latitude Case Study

Abstract: Seasonality plays a key role in altering the terrain of many military operating environments. Since seasonality has such a large impact on the terrain, it needs to be properly accounted for in vehicle dynamics models. This work outlines a variety of static and dynamic seasonal terrain conditions and their impacts on vehicle mobility in an austere region of Europe. Overall the vehicles performed the best in the dry season condition. The thaw season condition had the most drastic impact on mobility with all but the heavy tracked vehicle being almost completely NOGO in the region. Overall, the heavy tracked vehicle had the best performance in all terrain conditions. These results highlight the importance of incorporating seasonal impacts on terrain into NRMM or any vehicle dynamics model. Future work will focus on collecting more data to improve the empirical relationships between vehicles and seasonal terrain conditions, thereby allowing for more accurate speed predictions.

13 May 2020

PUBLICATION NOTICE: Assessment for Soil Reuse Standards at McMurdo Station

Abstract:  The soils at McMurdo Station in Antarctica contain hydrocarbons derived from accidental fuel spills and industrial development. The current practice for contaminated soils is to remove any material with concentrations greater than 100 mg/kg of total petroleum hydrocarbons (TPH) and to transport them to the United States for disposal. Any soils that contain concentrations of TPH less than 100 mg/kg can be reused on-site. While this is the current standard practice, there remains little evidence to verify that 100 mg/kg is an appropriate reuse standard. Moreover, the current practice is based on the guidelines for cleanup values in California (the port of entry where the soils are currently shipped for treatment and disposal), which has few environmental similarities with Antarctica. In the present study, we investigate current regulations for cleanup and soil reuse in U.S. states, Canadian territories, and other countries with cold climates. We also discuss case studies from Arctic and Antarctic regions where soil has been reused after treatment. Additionally, we present a site conceptual model for risk assessment based on known site information and recommend future focus areas for addressing hydrocarbon-contaminated soils at McMurdo Station.