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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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Sonic horizons and causality in phase transition dynamics

A system gradually driven through a symmetry-breaking phase transition is subject to the Kibble-Zurek mechanism (KZM). As a consequence of the critical slowing down, its state cannot follow local equilibrium, and its evolution becomes nonadiabatic near the critical point. In the simplest approximation, that stage can be regarded as an “impulse” where the state of the system remains unchanged. It leads to the correct KZM scaling laws. However, such a “freeze-out” might suggest that the coherence length of the nascent order parameter remains unchanged as the critical region is traversed. By contrast, the original causality-based discussion emphasized the role of the sonic horizon: Domains of the broken symmetry phase can expand with a velocity limited by the speed of the relevant sound. This effect was demonstrated in the quantum Ising chain where the dynamical exponent z = 1 and quasiparticles excited by the transition have a fixed speed of sound. To elucidate the role of the sonic horizon, in this paper we study two systems with z > 1 where the speed of sound is no longer fixed, and the fastest excited quasiparticles set the size of the sonic horizon. Their effective speed decays with increasing transition time. In the extreme case, the dynamical exponent z can diverge such as in the Griffiths region of the random Ising chain where the localization of excited quasiparticles freezes the growth of the correlation range when the critical region is traversed. Of particular interest is an example with z < 1 , the long-range extended Ising chain, where there is no upper limit to the velocity of excited quasiparticles with small momenta. Initially, the power-law tail of the correlation function grows adiabatically, but in the nonadiabatic stage it lags behind the adiabatic evolution.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2025

Site G - Sonic Anemometer / Reviewed Data

This dataset contains sonic anemometer data deployed on tethered balloon system at AWAKEN site G. The sonic data include time stamp, wind speed, wind direction, turbulence, and boom attitude and motion. Z02 refers to the second height position of the sonic anemometers mounted on the tethered balloon.

17 WIND ENERGY↗
DOE OSTI2025

Site G - Sonic Anemometer / Reviewed Data

This dataset contains sonic anemometer data deployed on tethered balloon system at AWAKEN site G. The sonic data include time stamp, wind speed, wind direction, turbulence, and boom attitude and motion. Z01 refers to the first height position of the sonic anemometers mounted on the tethered balloon.

17 WIND ENERGY↗
DOE OSTI2025

Dissolved Oxygen Redox as the Source of Hydrogen Peroxide and Hydroxyl Radical in Sonicated Emulsive Water Microdroplets

Sonicated emulsive water microdroplets (SEWMs) accelerate and enable a variety of catalyst-free chemical transformations. However, significant unanswered questions remain regarding the chemical intermediates they form and their possible redox origin. In this study, we identified dissolved O 2 as the primary originator of reactive oxygen species (ROS) such as OH• and H 2 O 2. We uncovered the role of dissolved O 2 redox by using a combination of microelectrochemical methods to detect H 2 O 2 , isotopic methods to identify the source of H 2 O 2 , and a combination of electron spin resonance and the DMPO spin trap to detect radicals such as OH•. Notably, we found that H 2 O 2 production is correlated with O 2 content via a reduction pathway enabled by a sufficiently large reducing power that can additionally generate H 2 and even perform Pb electroless deposition on Au and Cu metal substrates. Building on our findings, continuous O 2 bubbling of SEWMs showed accumulation of H 2 O 2 up to ∼88 mM in the aqueous phase within 1 h of sonication, demonstrating the scale-up promise of this method. Distinct to sonochemistry of a single phase, this study advances our understanding of the confluence of redox and chemical reaction mechanisms within SEWMs as a biphasic system. This insight paves the way for improving their reaction kinetics, yield, and selectivity, positioning these attractive redox microreactors as alternatives to traditional electrolyzers.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Sonic Lift-off of GaAs-based Solar Cells with Reduced Surface Facets

Spalling has been proposed as a promising kerfless technique for slicing thin wafers and devices, enhancing the wafer yield from an ingot by reducing kerf-losses and enabling substrate reuse for the case of costly devices. The main challenge of spalling is to control the roughness and thickness variation of the spalled wafers that can be as high as 100% of the wafer thickness. Here, we have shown previously that the thickness variations are largely influenced by the interaction of the crack front with its own reflected waves. Herein we show that through Sonic Lift-off we can offer a modification to standard spalling technologies that minimizes the interaction of reflected waves with the crack front during lift-off of GaAs(100)-based solar cells. We show that the average surface facets amplitude can be reduced by 96% while obtaining a high quality bulk with no discernible residual strain as measured by PL. The resulting spalling depth can easily be tuned from 100 µm to less than 15µm. The electrical characterization of the Sonic lift-off cell shows no degradation of the VOC and a power conversion within 99% relative of a non-spalled baseline.

42 ENGINEERING↗
DOE OSTI2025

Site A1 - Sonic Anemometer / Reviewed Data

This dataset contains sonic anemometer data deployed on tethered balloon system at AWAKEN site A1. The sonic data include time stamp, wind speed, wind direction, turbulence, and boom attitude and motion.

17 WIND ENERGY↗
DOE OSTI2025

TTP - WREF 3D Sonic Anemometer Tower D / Raw Data

Tower D is one of four subcanopy towers that were installed in the WREF canopy across a transect distance of 200m. Tower D had one CSAT3-3D sonic mounted at a height of 2.7 m a.g.l. The sonic is facing 290 degrees. The towers were installed to observe flow just above the forest floor and to identify any advection flows in the canopy. These data were also part of a larger ICOS project looking at forest flow coupling/decoupling with tower sites in Italy and Czech Republic.

17 WIND ENERGY↗
DOE OSTI2025

TTP - WREF 3D Sonic Anemometer Tower C / Raw Data

Tower C is one of four subcanopy towers that were installed in the WREF canopy across a transect distance of 200m. Tower C had one CSAT3-3D sonic mounted at a height of 2.7 m a.g.l. The sonic is facing 270 degrees. The towers were installed to observe flow just above the forest floor and to identify any advection flows in the canopy. These data were also part of a larger ICOS project looking at forest flow coupling/decoupling with tower sites in Italy and Czech Republic.

17 WIND ENERGY↗
DOE OSTI2023

Pilot decision space for sonic boom impact resolution

A system for predicting pressure waves in a sonic boom footprint calculates alternative footprints and pressure waves along a flight path based on speed and altitude modifiers. The available, adjustable parameters are bounded within a flight envelope and along an approved flight corridor. The system receives and incorporates data from external sources, such as weather data, that impacts sonic boom pressure wave predictions and aircraft performance characteristics.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2025

Solar Cell Performance after Exfoliation Using Sonic Liftoff

Removing grown device layers from a GaAs substrate is an essential aspect of reducing costs of III–V photovoltaics. While many methods of device layer removal have been explored, Sonic Lift‐off (SLO) demonstrates novel control of the stress conditions within the substrate during exfoliation. By utilizing acoustic energy, this technique allows for a lower maximum stress required to fully lift‐off layers from a substrate. We demonstrate that this technique results in no damage to inverted‐grown and upright‐grown exfoliated devices. The inverted device demonstrated an efficiency of 26.8% after SLO in comparison to 26.5% for a traditionally‐processed cell, and the upright device showed a 22.0% efficiency after SLO. The SLO process has been shown to produce exfoliated, damage‐free devices and opens the door for substrate reuse to reduce the cost of III–V photovoltaics.

14 SOLAR ENERGY↗
DOE OSTI2020

Sonic Detection and Ranging (SODAR) Wind Profiler Instrument Handbook

The SODAR (Sonic Detection and Ranging) wind profiler measures wind profiles and backscattered signal strength between (nominally) 15 meters (m) and 500 m. It operates by transmitting acoustic energy into the atmosphere and measuring the strength and frequency of backscattered energy. The strength of the backscattered signal is determined by the strength of temperature inhomogeneities with size on the order of 10 centimeters (cm). Assuming the scattering elements in the atmosphere are moving with the mean wind, the horizontal wind field can be derived. The U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility Mobile Facility (AMF) has a system developed by Scintec, Inc. that transmits a sequence of frequencies to enhance signal determination.

17 WIND ENERGY↗
DOE OSTI2024

Sonic Wafering of III-V substrates for High Efficiency Cells: A path to <$0.50/W

This project developed and demonstrated Sonic Lift-off, a novel technology that enables the reuse of expensive semiconductor substrates used to manufacture high-efficiency solar cells. By using sound waves to precisely separate thin layers of material, the process significantly reduces manufacturing costs while maintaining the performance of advanced III–V solar cells. These solar cells are among the most efficient in the world and are used in space, aerospace, and emerging terrestrial applications. The results of this work show that substrate reuse can be achieved without degrading device performance, offering a pathway to more affordable, high-performance solar technologies. This advancement supports U.S. clean energy goals by enabling broader deployment of renewable energy systems and strengthening domestic manufacturing capabilities in advanced photovoltaics.

14 SOLAR ENERGY↗