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Your search keyword '"Neilsen, Tracianne B."' showing total 559 results
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559 results on '"Neilsen, Tracianne B."'

1. Magnetised quark nuggets in the atmosphere

Author

Sloan, T., VanDevender, J. Pace, Neilsen, Tracianne B., Baskin, Robert L., Fronk, Gabriel, Swaim, Criss, Zakirov, Rinat, and Jones, Haydn

Subjects
High Energy Physics - Experiment, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

A search for magnetised quark nuggets (MQN) is reported using acoustic signals from hydrophones placed in the Great Salt Lake (GSL) in the USA. No events satisfying the expected signature were seen. This observation allows limits to be set on the flux of MQNs penetrating the atmosphere and depositing energy in the GSL. The expected signature of the events was derived from pressure pulses caused by high-explosive cords between the lake surface and bottom at various locations in the GSL. The limits obtained from this search are compared with those obtained from previous searches and are compared to models for the formation of MQNs.

Published
2021

11. Infrasonic crackle and supersonic jet noise from the eruption of Nabro Volcano, Eritrea

Author

Fee, David, Matoza, Robin S, Gee, Kent L, Neilsen, Tracianne B, and Ogden, Darcy E

Subjects
infrasound, volcanic jet, crackle, supersonic, Nabro, Meteorology & Atmospheric Sciences
Abstract

The lowermost portion of an explosive volcanic eruption column is considered a momentum-driven jet. Understanding volcanic jets is critical for determining eruption column dynamics and mitigating volcanic hazards; however, volcanic jets are inherently difficult to observe due to their violence and opacity. Infrasound from the 2011 eruption of Nabro Volcano, Eritrea has waveform features highly similar to the "crackle" phenomenon uniquely produced by man-made supersonic jet engines and rockets and is characterized by repeated asymmetric compressions followed by weaker, gradual rarefactions. This infrasonic crackle indicates that infrasound source mechanisms in sustained volcanic eruptions are strikingly similar to jet noise sources from heated, supersonic jet engines and rockets, suggesting that volcanologists can utilize the modeling and physical understandings of man-made jets to understand volcanic jets. The unique, distinctive infrasonic crackle from Nabro highlights the use of infrasound to remotely detect and characterize hazardous eruptions and its potential to determine volcanic jet parameters. Key Points Nabro Volcano produced sound similar to supersonic jet engines and rockets Volcanic and man-made jets have similar sound source mechanisms Infrasound can remotely detect and characterize volcanic eruptions and jets. © 2013. American Geophysical Union. All Rights Reserved.

Published
2013

25. Accurate Broadband Gradient Estimates Enable Local Sensitivity Analysis of Ocean Acoustic Models.

Author

Mortenson, Michael C., Neilsen, Tracianne B., Transtrum, Mark K., and Knobles, David P.

Subjects
*ACOUSTIC models, *SENSITIVITY analysis, *FISHER information, *INVERSE problems, *EXTRAPOLATION
Abstract

Sensitivity analysis is a powerful tool for analyzing multi-parameter models. For example, the Fisher information matrix (FIM) and the Cramér–Rao bound (CRB) involve derivatives of a forward model with respect to parameters. However, these derivatives are difficult to estimate in ocean acoustic models. This work presents a frequency-agnostic methodology for accurately estimating numerical derivatives using physics-based parameter preconditioning and Richardson extrapolation. The methodology is validated on a case study of transmission loss in the 50–400 Hz band from a range-independent normal mode model for parameters of the sediment. Results demonstrate the utility of this methodology for obtaining Cramér–Rao bound (CRB) related to both model sensitivities and parameter uncertainties, which reveal parameter correlation in the model. This methodology is a general tool that can inform model selection and experimental design for inverse problems in different applications. [ABSTRACT FROM AUTHOR]

Published
2023
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26. Acoustics for the Deaf: Can You See Me Now?

Author

Vongsawad, Cameron T., Berardi, Mark L., and Neilsen, Tracianne B.

Abstract

Although acoustics examples and demonstrations can be an effective tool for engaging students in introductory physics classes and outreach, teaching principles of sound and vibration to the deaf and hard of hearing needs to be approached carefully. The deaf and hard of hearing have less intuition with sound but are no strangers to some of the effects of pressure, vibrations, and other basic principles that are related to sound. We recently expanded our "Sounds to Astound" outreach program and developed an acoustics demonstration program for 80 visiting deaf students mostly between the ages of 13 and 18. Both this experience, which had a "See and Feel" approach, similar to what was proposed by Lang, and a specialized planetarium program helped reinforce for the students the opportunities that exist for them in higher education. This paper describes some of the pedagogical underpinnings, the demonstrations, their implementation and lessons learned, and student responses.

Published
2016
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27. HoloOcean: Realistic Sonar Simulation

Author

Potokar, Easton, primary, Lay, Kalliyan, additional, Norman, Kalin, additional, Benham, Derek, additional, Neilsen, Tracianne B., additional, Kaess, Michael, additional, and Mangelson, Joshua G., additional

Published
2022
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31. Graduate acoustics at Brigham Young University

Author

Allen, Matthew S., primary, Anderson, Brian E., additional, Blotter, Jonathan D., additional, Gee, Kent L., additional, Neilsen, Tracianne B., additional, Shepherd, Micah, additional, and Sommerfeldt, Scott D., additional

Published
2022
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32. Sounds to Astound: An acoustics outreach show

Author

Whiting, Jennifer K., primary, Berardi, Mark L., additional, Vaughn, Aaron B., additional, Vongsawad, Cameron T., additional, Neilsen, Tracianne B., additional, Anderson, Brian E., additional, and Gee, Kent L., additional

Published
2022
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33. Experimental Multiblast Craters and Ejecta—Seismo‐Acoustics, Jet Characteristics, Craters, and Ejecta Deposits and Implications for Volcanic Explosions

Author

Sonder, Ingo, primary, Graettinger, Alison, additional, Neilsen, Tracianne B., additional, Matoza, Robin S., additional, Taddeucci, Jacopo, additional, Oppenheimer, Julie, additional, Lev, Einat, additional, Tsunematsu, Kae, additional, Waite, Greg, additional, Valentine, Greg A., additional, and Befus, Kenneth S., additional

Published
2022
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40. Supervised Classification of Sound Speed Profiles via Dictionary Learning.

Author

Castro-Correa, Jhon A., Arnett, Stephanie A., Neilsen, Tracianne B., Wan, Lin, and Badiey, Mohsen

Subjects
UNDERWATER acoustics, ISOTROPIC properties, ORTHOGONAL functions, CLASSIFICATION, SOUND waves, SPEED of sound
Abstract

The presence of internal waves (IWs) in the ocean alters the isotropic properties of sound speed profiles (SSPs) in the water column. Changes in the SSPs affect underwater acoustics since most of the energy is dissipated into the seabed due to the downward refraction of sound waves. In consequence, variations in the SSP must be considered when modeling acoustic propagation in the ocean. Empirical orthogonal functions (EOFs) are regularly employed to model and represent SSPs using a linear combination of basis functions that capture the sound speed variability. A different approach is to use dictionary learning to obtain a learned dictionary (LD) that generates a nonorthogonal set of basis functions (atoms) that generate a better sparse representation. In this paper, the performance of EOFs and LDs are evaluated for sparse representation of SSPs affected by the passing of IWs. In addition, an LD-based supervised framework is presented for SSP classification and is compared with classical learning models. The algorithms presented in this work are trained and tested on data collected from the Shallow Water Experiment 2006. Results show that LDs yield lower reconstruction error than EOFs when using the same number of bases. In addition, overcomplete LDs are demonstrated to be a robust method to classify SSPs during low, medium, and high IW activity, reporting accuracy that is comparable to and sometimes higher than that of standard supervised classification methods. [ABSTRACT FROM AUTHOR]

Published
2023
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43. Magnetised quark nuggets in the atmosphere

Author

Sloan, T., primary, VanDevender, J. Pace, additional, Neilsen, Tracianne B., additional, Baskin, Robert L., additional, Fronk, Gabriel, additional, Swaim, Criss, additional, Zakirov, Rinat, additional, and Jones, Haydn, additional

Published
2021
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