Research
Research

Publications

Results 12701–12750 of 100,993

Search results

Jump to search filters

Comparison of Infrasound Wind Noise Reduction Systems for Use in Temporary Deployments

Albert, Sarah; Pankow, Kristine; Berg, Elizabeth M.

Infrasound, or low frequency sound 20 Hz, is produced by a variety of natural and anthropogenic sources. Wind also generates signals within this frequency band and serves as a persistent source of infrasonic noise. Infrasound sensors measure pressure fluctuations, which scale with the ambient density and velocity fluctuations of ground winds. Here we compare four different wind noise reduction systems, or "filters", and make recommendations for their use in temporary infrasound deployments. Our results show that there are two filters that are especially effective at reducing wind noise: (1) a Hyperion high frequency (HF) shroud with a 1 m diameter metal mesh dome placed on top and (2) a Hyperion Four Port Garden Hose shroud with 4 Miracle-Gro Soaker System garden hoses. We also find that placing a 5-gallon bucket over the HF wind shroud should not be done as it provides a negligible decrease in noise up to ~ 1 Hz and then an increase in noise. We conclude that it is up to the researcher to determine which of the other filters is best for their needs based on location and expense. We anticipate this study will be used as a resource for future deployments when a wind noise reduction method is necessary but only needed for a limited time period.

More Details
TYPE SAND Report YEAR 2021
DOIOSTIDOIOSTI

Effects of Radiation Reaction Physics on High-Current Power Flow

Hess, Mark H.; Evstatiev, Evstati G.

In this study, we examine the effects of the radiation reaction force on electrons in a radial magnetically insulated transmission line (MITL) near a load with peak currents of 60+ MA. More specifically, we study the differences in electron motion and kinetic energy with or without radiation reaction physics using a novel guiding center drift approach that incorporates E $\times$ B and ∇B drifts. A key finding of this study is that an electron's magnetic moment, which would be conserved when radiation reaction physics is not incorporated, can be significantly reduced in magnetic fields on the order of 10,000's T when radiation reaction is included. The reduction of magnetic moment gives rise to a significant reduction in cycloidal kinetic energy as well as a reduction in the electron's ∇B drift.

More Details
TYPE SAND Report YEAR 2021
DOIDOIOSTIOSTI

Developing a platform to enable parameter scaling studies in Magnetized Liner Inertial Fusion experiments

Gomez, Matthew R.; Slutz, Stephen A.; Jennings, Christopher A.; Weis, Matthew R.; Lamppa, Derek C.; Harvey-Thompson, Adam J.; Geissel, Matthias; Awe, Thomas J.; Chandler, Gordon A.; Crabtree, Jerry A.; Fein, Jeffrey R.; Hansen, Stephanie B.; Harding, Eric; Bays, Nathan R.; Mangan, Michael A.; Ruiz, Daniel E.; Smith, Ian C.; Yager-Elorriaga, David A.; Ampleford, David; Beckwith, Kristian

Abstract not provided.

More Details
TYPE Conference Presentation YEAR 2021
DOIOSTI

Programmatic Advantages of Linear Equivalent Seismic Models

Preston, Leiph; Eliassi, Mehdi; Poppeliers, Christian

Underground explosions nonlinearly deform the surrounding earth material and can interact with the free surface to produce spall. However, at typical seismological observation distances the seismic wavefield can be accurately modeled using linear approximations. Although nonlinear algorithms can accurately simulate very near field ground motions, they are computationally expensive and potentially unnecessary for far field wave simulations. Conversely, linearized seismic wave propagation codes are orders of magnitude faster computationally and can accurately simulate the wavefield out to typical observational distances. Thus, devising a means of approximating a nonlinear source in terms of a linear equivalent source would be advantageous both for scenario modeling and for interpretation of seismic source models that are based on linear, far-field approximations. This allows fast linear seismic modeling that still incorporates many features of the nonlinear source mechanics built into the simulation results so that one can have many of the advantages of both types of simulations without the computational cost of the nonlinear computation. In this report we first show the computational advantage of using linear equivalent models, and then discuss how the near-source (within the nonlinear wavefield regime) environment affects linear source equivalents and how well we can fit seismic wavefields derived from nonlinear sources.

More Details
TYPE SAND Report YEAR 2021
DOIOSTIDOIOSTI

LocOO3D User's Manual

Davenport, Kathy; Conley, Andrea C.; Downey, Nathan J.; Ballard, Sanford; Hipp, James R.; Begnaud, Michael A.

LocOO3D is a software tool that computes geographical locations for seismic events at regional to global scales. This software has a rich set of features, including the ability to use custom 3D velocity models, correlated observations and master event locations. The LocOO3D software is especially useful for research related to seismic monitoring applications, since it allows users to easily explore a variety of location methods and scenarios and is compatible with the CSS3.0 data format used in monitoring applications. The LocOO3D software, User's Manual, and Examples are available on the web at: https://github.com/sandialabs/LocOO3D For additional information on GeoTess, SALSA3D, RSTT, and other related software, please see: https://github.com/sandialabs/GeoTessJava, www.sandia.gov/geotess, www.sandia.gov/salsa3d, and www.sandia.gov/rstt

More Details
TYPE SAND Report YEAR 2021
DOIDOIOSTIOSTI

PCalc User's Manual

Conley, Andrea C.; Downey, Nathan J.; Ballard, Sanford; Hipp, James R.; Hammond, Patrick; Davenport, Kathy; Begnaud, Michael E.

PCalc is a software tool that computes travel-time predictions, ray path geometry and model queries. This software has a rich set of features, including the ability to use custom 3D velocity models to compute predictions using a variety of geometries. The PCalc software is especially useful for research related to seismic monitoring applications.

More Details
TYPE SAND Report YEAR 2021
DOIOSTIDOIOSTI

Energy Efficient Computing R&D Roadmap Outline for Automated Vehicles

Aitken, Rob; Nakahira, Yorie; Strachan, John P.; Bresniker, Kirk; Young, Ian; Li, Zhiyong; Klebanoff, Leonard E.; Burchard, Carrie; Kumar, Suhas; Marinella, Matthew; Severa, William M.; Talin, Albert A.; Vineyard, Craig M.; Mailhiot, Christian; Dick, Robert; Lu, Wei; Mogill, Jace

Automated vehicles (AV) hold great promise for improving safety, as well as reducing congestion and emissions. In order to make automated vehicles commercially viable, a reliable and highperformance vehicle-based computing platform that meets ever-increasing computational demands will be key. Given the state of existing digital computing technology, designers will face significant challenges in meeting the needs of highly automated vehicles without exceeding thermal constraints or consuming a large portion of the energy available on vehicles, thus reducing range between charges or refills. The accompanying increases in energy for AV use will place increased demand on energy production and distribution infrastructure, which also motivates increasing computational energy efficiency.

More Details
TYPE Other Report YEAR 2021
DOIOSTI
Results 12701–12750 of 100,993
Results 12701–12750 of 100,993
Top