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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

A Biomimetic Ultrasonic Whistle for Use as a Bat Deterrent on Wind Turbines

Our project goal was to design a novel mechanical ultrasonic deterrent for use on wind turbines in order to reduce bat fatalities around these structures. Our proposed deterrent design would be composed of a series of ultrasonic pulse generators, or whistles, affixed to a wind turbine blade, which produce ultrasound through mechanical means. The whistles would produce sounds mimicking the spectrotemporal patterns of bat echolocation pulses, thereby enhancing the bats’ ability to detect, localize and avoid the moving blades. These whistles are intended to be operated passively, blown by the wind, and to be positioned at intervals along a turbine blade. Because the source of sound generation will be mechanical in nature, these devices will require no external power source, should require little maintenance, and will be small and cost-effective.

17 WIND ENERGY↗
DOE OSTI2025

Euro-Deterrent: Analysis of Proposals for a European Nuclear Arsenal (CNSIS Paper)

The idea of a “Euro-deterrent”—a nuclear arsenal under European control and mandated to protect multiple European countries—has been proposed many times as a means for European self-defense independent of United States security guarantees under the North Atlantic Treaty Organization (NATO). This paper examines not only the concept’s multiple guises, but the reasons for their failure. It will address the idea of a Franco-British umbrella, a French umbrella, a European “pool”, and the nuclear arsenal of a hypothetical “united Europe”. Reasons for rejection largely fall into three categories: sovereignty concerns, credibility gaps, and a desire to preserve existing norms and structures. This paper concludes that the Euro-deterrent will likely remain only hypothetical unless the US unequivocally signals its intent to withdraw its nuclear umbrella from Europe, thereby forcing European countries to build a new defense arrangement.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2024

Ultrasonic Deterrents To Reduce Bat Mortality at Wind Turbines - Short Science Summary

In North America, several bat species commonly collide with operating turbines. Though the ultimate driver of collisions is unknown, studies suggest that bats may be attracted to turbines because they often approach and spend extended periods of time (seconds to minutes) interacting with turbine structures. To reduce bat mortality at wind farm operators, seek to reduce mortality rates by reducing the amount of time that bats interact with spinning turbine blades (or exposure). Current approaches to reduce exposure include curtailment, whereby turbine operators stop turbine rotors from spinning during periods when bats are expected to be at the highest risk of collision, and deterrent technologies that seek to discourage bats from entering/ limit the amount of time spent within the rotor swept area. We briefly describe the state of the science on ultrasonic deterrent technology, highlight potential drivers of variable efficacy for bat mortality reduction, and suggest next steps focus on identifying the driver(s) of such variability.

bats↗
DOE OSTI2021

Strategic Weapons in the 21st Century The U.S. Nuclear Deterrent in 2030 and Beyond: Fit for Purpose?

The 13th annual Strategic Weapons in the 21st Century (SW21) workshop brought together a mixture of senior officials from the laboratory, policy, military, and expert communities to promote a high-level focus and well-informed discussion on key deterrence challenges for the U.S. nuclear deterrent over the coming decade and beyond. It brought together interested stakeholders from the national security laboratories, federal government, military, think tank, and academic communities, as well as allied counterparts, to share perspectives in an unclassified setting.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2020

Bat Impact Minimization Technology: An Improved Bat Deterrent for the Full Swept Rotor Area of Any Wind Turbine

The growth in the number of wind turbine generators has led to a significant number of fatal interactions with bat species. The need to reduce the number of bat fatalities while minimizing power losses is the greatest conservation challenge for wind energy development in parts of the country, according to the American Wind Wildlife Institute. Technological solutions that can also allow turbines to operate normally would generate the maximum electricity and avoid financial losses. Bats use echolocation to perceive their surroundings by listening to features of echoes from their high frequency vocal signals reflecting from targets. In this project, Frontier Wind built on previous research demonstrating that ultrasonic noise can mask echolocation and act as a repellent or deterrent to bat flight activity. Whereas the initial study only broadcast ultrasonic transmissions from the center of the turbine, the Strike Free™ system developed for this project extended the ultrasonic coverage to the entire area swept by the turbine blades. Frontier Wind designed the system components and their integration and then tested them in the lab and in the field at Pattern Energy’s Hatchet Ridge Wind Facility near Redding, California. The researchers used an acoustic model to determine the optimal configuration of transmitters along the blades to provide sound transmission coverage across the turbine rotor swept area volume. The custom ultrasonic transmitters were designed specifically for the echolocation frequencies of the four main bat species that have been shown to have died at Hatchet Ridge, although the transmitters can be customized for different frequencies as needed in other geographic locations. The Strike Free™ system shows promise for reducing bat fatalities, and the path to commercialization requires further testing to validate and optimize performance in the field.

17 WIND ENERGY↗
DOE OSTI2024

Experimental trials of species-specific bat flight responses to an ultrasonic deterrent

Unintended consequences of increasing wind energy production include bat mortalities from wind turbine blade strikes. Ultrasonic deterrents (UDs) have been developed to reduce bat mortalities at wind turbines. Our goal was to experimentally assess the species-specific effectiveness of three emission treatments from the UD developed by NRG Systems. We conducted trials in a flight cage measuring approximately 60 m × 10 m × 4.4 m (length × width × height) from July 2020 to May 2021 in San Marcos, Texas, USA. A single UD was placed at either end of the flight cage, and we randomly selected one for each night of field trials. Trials focused on a red bat species group (Lasiurus borealis and Lasiurus blossevillii; n = 46) and four species: cave myotis (Myotis velifer; n = 57), Brazilian free-tailed bats (Tadarida brasiliensis; n = 73), evening bats (Nycteceius humeralis; n = 53), and tricolored bats (Perimyotis subflavus; n = 17). The trials occurred during three treatment emissions: low (emissions from subarrays at 20, 26, and 32 kHz), high (emissions from subarrays at 38, 44, and 50 kHz), and combined (all six emission frequencies). We placed one wild-captured bat into the flight cage for each trial, which consisted of an acclimation period, a control period with the UD powered off, and the three emission treatments (order randomly selected), each interspersed with a control period. We tracked bat flight using four thermal cameras placed outside the flight cage. We quantified the effectiveness of each treatment by comparing the distances each bat flew from the UD during each treatment vs. the control period using quantile regression. Additionally, we conducted an exploratory analysis of differences between sex and season and sex within season using analysis of variance. Broadly, UDs were effective at altering the bats’ flight paths as they flew farther from the UD during treatments than during controls; however, results varied by species, sex, season, and sex within season. For the red bat group, bats flew farther from the UD during all treatments than during the control period at all percentiles (p < 0.001), and treatments were comparable in effectiveness. For cave myotis, all percentile distances were farther from the UD during each of the treatments than during the control, except the 90th percentile distance during high, and low was most effective. For evening bats and Brazilian free-tailed bats, results were inconsistent, but high and low were most effective, respectively. For tricolored bats, combined and low were significant at the 10th–75th percentiles, high was significant at all percentiles, and combined was most effective. Results suggest UDs may be an effective means of reducing bat mortalities due to wind turbine blade strikes. We recommend that continued research on UDs focus on low emission treatments, which have decreased sound attenuation and demonstrated effectiveness across the bat species evaluated in this study.

17 WIND ENERGY↗
DOE OSTI2020

LANSCE 21st Century Deterrence

The LANSCE accelerator is an important tool in the assessment and certification of the nation’s nuclear stockpile. LANSCE provides critical materials and nuclear data needed to develop a predictive capability for the performance of nuclear weapons. As the stockpile ages, materials are replaced, and manufacturing processes change, it is critical that we understand how these changes impact device performance. Dynamic proton radiography and neutron diffraction are ideally suited to contribute to this need. These capabilities are essential to enabling the NNSA labs to become more responsive and agile in advancing the deterrent of the future.

43 PARTICLE ACCELERATORS↗
DOE OSTI2020

Nuclear Weapons Deterrence Concepts

Deterrence is the action of discouraging an action or event through instilling doubt or fear of the consequences. Our security hedge in an uncertain world discourages our adversaries & reassures our allies.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2022

You Can't Spell Integrated Deterrence Without 'E'

Instruments of national power include DIME (Diplomatic, Information, Military, and Economic). In light of the 2022 National Defense Strategy, when considering a fully integrated deterrence model, the US must leverage each and every one of these instruments; and in the case of China, especially the economic ‘E’. This paper highlights the current problems with the Sino-American economic relationship and proposes a solution that will enhance the competitive position and national power of the US.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2023

Pits 101: The true meaning of deterrence

Mark Davis (ALDWP-COO) is the Chief Operation Officer for the Associate Laboratory Directorate of Weapons Production, where he focuses on ramping up operations in the Plutonium Facility in support of the directorate's programs, including the plutonium pit mission. Davis has had an accomplished career in the U.S. Navy that has compelled him to inspire those who support our nation's national security through sharing stories of our nation's history and the individuals who have been world-changers. He is passionate not only about our national security mission here at the Lab, but also about ensuring every employee understands that they play a key role in the mission, no matter their day job. In this special edition of the Pits 101 series, Public Affairs sat down with Davis to get his perspective on the meaning of credible and sustainable strategic deterrence, and why it matters today.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2020

Multiscale Approach to Fast ModSim for Laser Processing of Metals for Future Nuclear Deterrence Environments

Predicting performance of parts produced using laser-metal processing remains an out- standing challenge. While many computational models exist, they are generally too computationally expensive to simulate the build of an engineering-scale part. This work develops a reduced order thermal model of a laser-metal system using analytical Green's function solutions to the linear heat equation, representing a step towards achieving a full part performance prediction in an "overnight" time frame. The developed model is able to calculate a thermal history for an example problem 72 times faster than a traditional FEM method. The model parameters are calibrated using a non-linear solution and microstructures and residual stresses calculated and compared to a non-linear case. The calibrated model shows promising agreement with a non-linear solution.

36 MATERIALS SCIENCE↗
DOE OSTI2022

The Optics of Deterrence: How Science Assures the Nuclear Stockpile's Reliability In Lieu of Testing

When designing a product intended to perform a certain function and satisfy some set of criteria, the standard engineering method to assess its ability to perform is to test it. This nearly universal concept works consistently, assuring proper function and generally avoiding or mitigating the consequence of failure to within acceptable limits. What would happen if the product developers were told that they must continue to certify and validate the performance without testing it, that the landscape in which the product must serve its purpose is constantly evolving, and that the product in question is the United States’ nuclear weapons stockpile? This is the position the National Nuclear Security Administration (NNSA) finds itself in; the reliability of the stockpile must be verified without actually testing it to see if it works as intended.

43 PARTICLE ACCELERATORS↗