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Conference Papers

Browse almost 5,000 conference papers authored by our scientists and refine search by topic, location, year, and advanced search.

Filter Total Items: 5585

Applications for General Purpose Command Buffers: The Emergency Conjunction Avoidance Maneuver Applications for General Purpose Command Buffers: The Emergency Conjunction Avoidance Maneuver

A case study is presented for the use of Relative Operation Sequence (ROS) command buffers to quickly execute a propulsive maneuver to avoid a collision with space debris. In this process, a ROS is custom-built with a burn time and magnitude, uplinked to the spacecraft, and executed in 15 percent of the time of the previous method. This new process provides three primary benefits. First...
Authors
Robert J Scheid, Martin England

Field scale test of multi-dimensional flow and morphodynamic simulations used for restoration design analysis Field scale test of multi-dimensional flow and morphodynamic simulations used for restoration design analysis

Two- and three-dimensional morphodynamic simulations are becoming common in studies of channel form and process. The performance of these simulations are often validated against measurements from laboratory studies. Collecting channel change information in natural settings for model validation is difficult because it can be expensive and under most channel forming flows the resulting...
Authors
Richard R. McDonald, Jonathan M. Nelson, Ryan L. Fosness, Peter O. Nelson

Noncontact methods for measuring water-surface elevations and velocities in rivers: Implications for depth and discharge extraction Noncontact methods for measuring water-surface elevations and velocities in rivers: Implications for depth and discharge extraction

Recently developed optical and videographic methods for measuring water-surface properties in a noninvasive manner hold great promise for extracting river hydraulic and bathymetric information. This paper describes such a technique, concentrating on the method of infrared videog- raphy for measuring surface velocities and both acoustic (laboratory-based) and laser-scanning (field-based)...
Authors
Jonathan M. Nelson, Paul J. Kinzel, Richard R. McDonald, Mark Schmeeckle

Late Neogene deformation of the Chocolate Mountains Anticlinorium: Implications for deposition of the Bouse Formation and early evolution of the Lower Colorado River Late Neogene deformation of the Chocolate Mountains Anticlinorium: Implications for deposition of the Bouse Formation and early evolution of the Lower Colorado River

Deformation related to late Neogene dextral shear can explain a shift from an estuarine to lacustrine depositional environment in the southern Bouse Formation north of Yuma, Arizona. We infer that late Neogene deformation in the Chocolate Mountain Anticlinorium (CMA) created a barrier that blocked an estuary inlet, and that pre-existing and possibly active structures subsequently...
Authors
Sue Beard, Gordon B. Haxel, Rebecca J. Dorsey, Kristin A. McDougall, Carl E. Jacobsen

GIS methodology for geothermal play fairway analysis: Example from the Snake River Plain volcanic province GIS methodology for geothermal play fairway analysis: Example from the Snake River Plain volcanic province

Play fairway analysis in geothermal exploration derives from a systematic methodology originally developed within the petroleum industry and is based on a geologic and hydrologic framework of identified geothermal systems. We are tailoring this methodology to study the geothermal resource potential of the Snake River Plain and surrounding region. This project has contributed to the...
Authors
Jacob DeAngelo, John W. Shervais, Jonathan M. Glen, Dennis L. Nielson, Sabodh Garg, Patrick Dobson, Erika Gasperikova, Eric Sonnenthal, Charles Visser, Lee M. Liberty, Drew Siler, James P. Evans, Sean Santellanes

Accretionary lapilli: what’s holding them together? Accretionary lapilli: what’s holding them together?

Accretionary lapilli from Tagus cone, Isla Isabela, Galápagos were analyzed using scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS) techniques. Our main findings are (1) the lapilli formed and hardened in a few minutes while still aloft in the dispersing eruption column. (2) Palagonite rinds developed first on the basaltic glass clasts, and subsequently...
Authors
Paul M. Adams, David K. Lynch, David C. Buesch

Depredation of the California Ridgway’s rail: Causes and distribution Depredation of the California Ridgway’s rail: Causes and distribution

We studied the causes of mortality for the California Ridgway’s rail at multiple tidal marshes in the San Francisco Bay Estuary, California. We radio-marked 196 individual rails and examined the evidence from 152 recovered California Ridgway’s rail mortalities from our radio-marked sample and determined plausible cause of death from a wide array of evidence. We also included 10...
Authors
Michael L. Casazza, Cory T. Overton, Thuy-Vy D. Bui, John Y. Takekawa, Angela M. Merritt, J.M. Hull

Detection and quantification of hydrocarbons in sediments Detection and quantification of hydrocarbons in sediments

A new technology developed by the US Geological Survey now allows for fast, direct detection of hydrocarbon plumes both in rivers and drifting in the deep ocean. Recent experiments show that the method can also detect and quantify hydrocarbons buried in river sediments and estuaries. This approach uses a variant of induced polarization, a surface-sensitive physical property of certain...
Authors
Jeff Wynn, Mike Williamson, Jeff Frank

Vulnerability of shortgrass prairie bird assemblages to climate change Vulnerability of shortgrass prairie bird assemblages to climate change

The habitats and resources needed to support grassland birds endemic to North American prairie ecosystems are seriously threatened by impending climate change. To assess the vulnerability of grassland birds to climate change, we consider various components of vulnerability, including sensitivity, exposure, and adaptive capacity (Glick et al. 2011). Sensitivity encompasses the innate
Authors
Susan K. Skagen, Victoria Dreitz, Reesa Y. Conrey, Amy Yackel, Arvind O. Panjabi
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