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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Assessing the Feasibility of Using Various Earth Observations to Monitor Environmental Trends Associated with River Flow Impediments Near Energy Intake Structures

Grassing events, characterized by the release of river vegetation in large quantities, are often responsible for major flow impediments surrounding industrial water intake structures. These sudden flow impediments halt critical municipal functions, such as cooling at energy generating facilities, leading to widespread energy disruptions for surrounding communities. Because the origin and cause of grassing events in rivers are largely unknown, employees at these facilities can only reactively respond after they occur by pausing energy generation to manually remove the accumulation of aquatic vegetation. In 2023, the Dresden Generating Station, in collaboration with the United States Geological Survey, began looking into using remote sensing methodologies to locate floating aquatic vegetation surrounding their intake structure located along the Kankakee River in northern Illinois. This project contributed to this effort by conducting a case study that compared the performance, practicality, and feasibility of using various Earth observations (Landsat 9 OLI-2, Landsat 8 OLI, Sentinel-2 MSI, and DOVE PlanetScope) and vegetation indices (NDVI, EVI, SAVI, and GCI) to monitor aquatic vegetation in the Kankakee River. Additionally, this study incorporated several environmental metrics to identify potential triggers for grassing events. Results from this project found that while Landsat sensors provide a lower spatial resolution than commercial satellite Earth observations, areas of aquatic vegetation were similarly identified; therefore, it may not be necessary to acquire expensive, high-resolution datasets for continued monitoring. Finally, preliminary correlation analyses showed a potential negative relationship between the river discharge and the presence of aquatic vegetation (-0.875 correlation coefficient), suggesting that periods of low flow could lead to large releases in aquatic vegetation.

Marisa Smedsrud↗
NASA NTRS2017

Searching the Gamma-Ray Sky for Counterparts to Gravitational Wave Sources Fermi Gamma-Ray Burst Monitor and Large Area Telescope Observations of LVT151012 and GW151226

We present the Fermi Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) observations of the LIGO binary black hole merger event GW151226 and candidate LVT151012. At the time of the LIGO triggers on LVT151012 and GW151226, GBM was observing 68% and 83% of the localization regions, and LAT was observing 47% and 32%, respectively. No candidate electromagnetic counterparts were detected by either the GBM or LAT. We present a detailed analysis of the GBM and LAT data over a range of timescales from seconds to years, using automated pipelines and new techniques for characterizing the flux upper bounds across large areas of the sky. Due to the partial GBM and LAT coverage of the large LIGO localization regions at the trigger times for both events, differences in source distances and masses, as well as the uncertain degree to which emission from these sources could be beamed, these non-detections cannot be used to constrain the variety of theoretical models recently applied to explain the candidate GBM counterpart to GW150914.

gamma rays: general – gravitational waves – me↗
NASA NTRS1992

BATSE observations of bremsstrahlung from electron precipitation events

The BATSE on-board burst system has been triggered by over 400 terrestrial electron precipitation events. These are the single largest cause of false triggers. Bremsstrahlung is generated as the precipitating electrons interact in the Earth's atmosphere, or in the spacecraft, and this radiation is detected by the Large Area Detectors, often triggering the instrument into burst mode. Several examples of such events are presented here, and the different classes of events are described. A possible correlation of events to strong magnetospheric activity is presented, and the association of a sub-set of events to a powerful VLF transmitter on the western coast of Australia is described.

Horack, J. M.↗
NASA NTRS1985

A possible EAS array above the Soudan 2 detector

Multiple high energy muons, when studied with a large area detector, can be useful in the study of the composition of cosmic rays at energies approx. 10 14 eV. The Soudan II detector, primarily designed to detect nucleon decay, is located approx. 600 m deep underground and has dimensions of 16m x 8m x 5m (height), and is made up of drift tubes. The minimum muon energy needed to penetrate that depth is approximately 500 GeV. A set of simulated cosmic ray showers was set up to calculate the rate of muon associated events, using a trigger array with the number of detectors varying from 37 to 127 (the radius of acceptance varying from 50m to 100m). The number used in the calculations is given. The association rate is seen to be a strong function of the multiplicity of muons in the detector. The difference in the rates of association of proton and nuclei induced showers rises rapidly with multiplicity.

Sivaprasad, K.↗
NASA NTRS1990

Reasoning visualization in expert systems - The applicability of algorithm animation techniques

This paper presents the results of research into providing a means for users to flexibly create visualizations of the reasoning processes of forward-chaining rule-based expert systems using algorithm animation techniques. Levels of reasoning are described in order to identify the information necessary from the expert system development environment for these visualizations. A dual-process visualization environment is presented consisting of: (1) a version of CLIPS modified for the identified information access requirements; and (2) VISOR, an algorithm animation-based system for creating visualizations of arbitrary complexity which can be triggered by 'interesting event' messages from the running expert-system application. This is followed by examples from several visualizations performed during the scope of this work.

Selig, William J.↗
NASA NTRS1993

Analysis of SOFCAL calibration data

Ionization calorimeters determine the total energy of a particle by absorbing, within the mass of the calorimeter, the entire energy of the particle or a significant (and determinable) fraction of it. The JACEE group has used passive ionization calorimetery, which employs photographic emulsions as the detector medium, to measure the charge composition and energy spectrum of cosmic rays up to, and exceeding, 10(exp 14)eV. The SOFIC approach depends similarly on the use of three-dimensional nuclear-electromagnetic shower theory to relate the ionization deposits obtained during a shower to the energy of the particle causing the shower. Bundles of thousands of scintillating optical fibers are read out using image-intensified CCD's. Such an event may be triggered by a fast shower detector placed under the instrument or if only heavy particles are of interest, from a fast primary Cerention detector placed above the calorimeter. In the first study, fast Hammatsu photomultiplier tubes were purchased and tested for possible application for a triggering purpose. In the second study, some refinements have been made to the theoretical treatment of hadronic interactions in the central collision region. These will be helpful in improving the simulations necessary for observations of high energy cosmic ray nuclei with a SOFIC.

Gregory, John C.↗
NASA NTRS1995

Catalog of solar wind events identified from observations by ISTP spacecraft

The ISTP Science Planning and Operations Facility (SPOF), in collaboration with ISTP investigators, is developing a catalog of solar wind events and features. The catalog is primarily based on plasma and magnetic field observations from the WIND and IMP-8 spacecraft. Interplanetary events that may trigger magnetospheric activity are included as well as features of interest for using the solar wind as a plasma laboratory. Catalog coverage begins on September 8, 1992, the start of ISTP science data collection. The catalog is based on Key Parameter data sets (preliminary summary data at approximately 1 min time resolution produced quickly for survey purposes) and as such has limited citability in formal scientific work. Its primary intent is to serve as a reference for identifying candidate periods for further study, such as may be the focus of coordinated data analysis efforts during ISTP and/or IACG Science Campaigns. To facilitate access by members of the ISTP and wider space physics communities, the catalog will be available on the World Wide Web. The contents of the catalog will be described, and samples of catalog information will be presented.

Peredo, M.↗
NASA NTRS2000

Complement activation promotes muscle inflammation during modified muscle use

Modified muscle use can result in muscle inflammation that is triggered by unidentified events. In the present investigation, we tested whether the activation of the complement system is a component of muscle inflammation that results from changes in muscle loading. Modified rat hindlimb muscle loading was achieved by removing weight-bearing from the hindlimbs for 10 days followed by reloading through normal ambulation. Experimental animals were injected with the recombinant, soluble complement receptor sCR1 to inhibit complement activation. Assays for complement C4 or factor B in sera showed that sCR1 produced large reductions in the capacity for activation of the complement system through both the classical and alternative pathways. Analysis of complement C4 concentration in serum in untreated animals showed that the classical pathway was activated during the first 2 hours of reloading. Analysis of factor B concentration in untreated animals showed activation of the alternative pathway at 6 hours of reloading. Administration of sCR1 significantly attenuated the invasion of neutrophils (-49%) and ED1(+) macrophages (-52%) that occurred in nontreated animals after 6 hours of reloading. The presence of sCR1 also reduced significantly the degree of edema by 22% as compared to untreated animals. Together, these data show that increased muscle loading activated the complement system which then briefly contributes to the early recruitment of inflammatory cells during modified muscle loading.

NASA Discipline Musculoskeletal↗
NASA NTRS2000

Paleoproterozoic snowball earth: extreme climatic and geochemical global change and its biological consequences

Geological, geophysical, and geochemical data support a theory that Earth experienced several intervals of intense, global glaciation ("snowball Earth" conditions) during Precambrian time. This snowball model predicts that postglacial, greenhouse-induced warming would lead to the deposition of banded iron formations and cap carbonates. Although global glaciation would have drastically curtailed biological productivity, melting of the oceanic ice would also have induced a cyanobacterial bloom, leading to an oxygen spike in the euphotic zone and to the oxidative precipitation of iron and manganese. A Paleoproterozoic snowball Earth at 2.4 Giga-annum before present (Ga) immediately precedes the Kalahari Manganese Field in southern Africa, suggesting that this rapid and massive change in global climate was responsible for its deposition. As large quantities of O(2) are needed to precipitate this Mn, photosystem II and oxygen radical protection mechanisms must have evolved before 2.4 Ga. This geochemical event may have triggered a compensatory evolutionary branching in the Fe/Mn superoxide dismutase enzyme, providing a Paleoproterozoic calibration point for studies of molecular evolution.

Earth (Planet)↗
NASA NTRS2005

Outflow Channels Influencing Martian Climate: Global Circulation Model Simulations with Emplaced Water

The existence of surface water on Mars in past geologic epochs is inferred on the basis of geomorphologic interpretation of spaceflight images, and is supported by the recent Mars Odyssey identification of ice-rich soils [1]. The Mars Exploration Rovers have provided further chemical evidence for past surface hydrologic activity [2]. One issue is whether this water-rich climate ever existed in a steady state, or whether it was triggered by catastrophic events such as large impacts [3], and/ or catastrophic outburst floods, the topic of consideration here.

Santiago, D. L.↗
NASA NTRS2005

An Impact Genesis for Loki Patera?

What happens when a large impact event takes place on a satellite with a thin crust and lithosphere? In the early Solar System impact cratering and volcanism were the dominate processes shaping the surfaces of the terrestrial planets. Impact events may have triggered additional volcanism by uplifting partially molten mantle material to the surface, where it melts due to pressure release. Subsequently, the shattered crust may have provided pathways for magma to reach the surface creating a longer term hot spot. As the crusts of the terrestrial planets thickened, the ability of impacts to trigger volcanism diminished [1]. However, the highly-volcanic jovian satellite Io is located in a "high-impact" area of the Solar System [2], a victim of material attracted by Jupiter s gravitational field. In 1994 huge impacts were observed when fragments of comet Shoemaker- Levy 9 impacted Jupiter. The large icy satellites of Jupiter (Europa, Ganymede and Callisto) are pockmarked with many impact craters. Yet no impact features have been found on Io [3]. This is because of rapid resurfacing of Io due to volcanism, estimated at approx.1 cm/year [4] which over short geological time erases evidence of impacts. Io, however, has a lithosphere over a molten or partially-molten mantle [e.g., 5], and the effects of a sufficiently large impact may extend far beyond the evolution of the impact crater alone. At least one example of impact-triggered volcanism may exist in the Solar System today: the Loki Patera complex on Io.

Thorsos, I. E.↗
NASA NTRS2005

The Effect of Line Maintenance Activity on Airline Safety Quality

One of the arguments against deregulation of the airline industry has been the possibility that financially troubled carriers would be tempted to lower line maintenance spending, thus lowering maintenance quality and decreasing the overall safety of the carrier. Given the financial crisis triggered by the events of 9/11: it appears to be a good time to revisit this issue. This paper examines the quality of airline line maintenance activity and examines the impact of maintenance spending on maintenance quality and overall safety. Findings indicate that increased maintenance spending is associated with increased line maintenance activity and increased overall safety quality for the major U.S. carriers.

Rhoades, Dawna L.↗
NASA NTRS2007

Neural Net Safety Monitor Design

The National Aeronautics and Space Administration (NASA) at the Dryden Flight Research Center (DFRC) has been conducting flight-test research using an F-15 aircraft (figure 1). This aircraft has been specially modified to interface a neural net (NN) controller as part of a single-string Airborne Research Test System (ARTS) computer with the existing quad-redundant flight control system (FCC) shown in figure 2. The NN commands are passed to FCC channels 2 and 4 and are cross channel data linked (CCDL) to the other computers as shown. Numerous types of fault-detection monitors exist in the FCC when the NN mode is engaged; these monitors would cause an automatic disengagement of the NN in the event of a triggering fault. Unfortunately, these monitors still may not prevent a possible NN hard-over command from coming through to the control laws. Therefore, an additional and unique safety monitor was designed for a single-string source that allows authority at maximum actuator rates but protects the pilot and structural loads against excessive g-limits in the case of a NN hard-over command input. This additional monitor resides in the FCCs and is executed before the control laws are computed. This presentation describes a floating limiter (FL) concept1 that was developed and successfully test-flown for this program (figure 3). The FL computes the rate of change of the NN commands that are input to the FCC from the ARTS. A window is created with upper and lower boundaries, which is constantly floating and trying to stay centered as the NN command rates are changing. The limiter works by only allowing the window to move at a much slower rate than those of the NN commands. Anywhere within the window, however, full rates are allowed. If a rate persists in one direction, it will eventually hit the boundary and be rate-limited to the floating limiter rate. When this happens, a persistent counter begins and after a limit is reached, a NN disengage command is generated. The tunable metrics for the FL are (1) window size, (2) drift rate, and (3) persistence counter. Ultimate range limits are also included in case the NN command should drift slowly to a limit value that would cause the FL to be defeated. The FL has proven to work as intended. Both high-g transients and excessive structural loads are controlled with NN hard-over commands. This presentation discusses the FL design features and presents test cases. Simulation runs are included to illustrate the dramatic improvement made to the control of NN hard-over effects. A mission control room display from a flight playback is presented to illustrate the neural net fault display representation. The FL is very adaptable to various requirements and is independent of flight condition. It should be considered as a cost-effective safety monitor to control single-string inputs in general.

Larson, Richard R.↗
NASA NTRS2007

US Plans for the JEM-EUSO

This viewgraph presentation reviews the planned United States work on the Extreme Universe Space Observatory (EUSO.) The EUSO is to be mounted to the JEM (Japanese Experiment Module). The plans areas for US participation are the Optics Investigations, Trigger Design and Event Reconstruction.

Adams, James H.↗
NASA NTRS2009

Implementation of an Adaptive Controller System from Concept to Flight Test

The National Aeronautics and Space Administration (NASA) at the Dryden Flight Research Center (DFRC) has been conducting flight-test research using an F-15 aircraft (figure 1). This aircraft has been specially modified to interface a neural net (NN) controller as part of a single-string Airborne Research Test System (ARTS) computer with the existing quad-redundant flight control system (FCC) shown in figure 2. The NN commands are passed to FCC channels 2 and 4 and are cross channel data linked (CCDL) to the other computers as shown. Numerous types of fault-detection monitors exist in the FCC when the NN mode is engaged; these monitors would cause an automatic disengagement of the NN in the event of a triggering fault. Unfortunately, these monitors still may not prevent a possible NN hard-over command from coming through to the control laws. Therefore, an additional and unique safety monitor was designed for a single-string source that allows authority at maximum actuator rates but protects the pilot and structural loads against excessive g-limits in the case of a NN hard-over command input. This additional monitor resides in the FCCs and is executed before the control laws are computed. This presentation describes a "floating limiter" (FL) concept that was developed and successfully test-flown for this program (figure 3). The FL computes the rate of change of the NN commands that are input to the FCC from the ARTS. A window is created with upper and lower boundaries, which is constantly "floating" and trying to stay centered as the NN command rates are changing. The limiter works by only allowing the window to move at a much slower rate than those of the NN commands. Anywhere within the window, however, full rates are allowed. If a rate persists in one direction, it will eventually "hit" the boundary and be rate-limited to the floating limiter rate. When this happens, a persistent counter begins and after a limit is reached, a NN disengage command is generated. The tunable metrics for the FL are (1) window size, (2) drift rate, and (3) persistence counter. Ultimate range limits are also included in case the NN command should drift slowly to a limit value that would cause the FL to be defeated. The FL has proven to work as intended. Both high-g transients and excessive structural loads are controlled with NN hard-over commands. This presentation discusses the FL design features and presents test cases. Simulation runs are included to illustrate the dramatic improvement made to the control of NN hard-over effects. A mission control room display from a flight playback is presented to illustrate the neural net fault display representation. The FL is very adaptable to various requirements and is independent of flight condition. It should be considered as a cost-effective safety monitor to control single-string inputs in general.

Larson, Richard R.↗
NASA NTRS2011

Predicting the Consequences of Workload Management Strategies with Human Performance Modeling

Human performance modelers at the US Army Research Laboratory have developed an approach for establishing Soldier high workload that can be used for analyses of proposed system designs. Their technique includes three key components. To implement the approach in an experiment, the researcher would create two experimental conditions: a baseline and a design alternative. Next they would identify a scenario in which the test participants perform all their representative concurrent interactions with the system. This scenario should include any events that would trigger a different set of goals for the human operators. They would collect workload values during both the control and alternative design condition to see if the alternative increased workload and decreased performance. They have successfully implemented this approach for military vehicle. designs using the human performance modeling tool, IMPRINT. Although ARL researches use IMPRINT to implement their approach, it can be applied to any workload analysis. Researchers using other modeling and simulations tools or conducting experiments or field tests can use the same approach.

Mitchell, Diane Kuhl↗
NASA NTRS2023

BatAnalysis - A Comprehensive Python Pipeline for Swift BAT Survey Analysis

The Swift Burst Alert Telescope (BAT) is a coded aperture gamma-ray instrument with a large field of view that primarily operates in survey mode when it is not triggering on transient events. The survey data consists of eighty-channel detector plane histograms that accumulate photon counts over time periods of at least 5 minutes. These histograms are processed on the ground and are used to produce the survey dataset between 14 and 195 keV. Survey data comprises >90% of all BAT data by volume and allows for the tracking of long term light curves and spectral properties of cataloged and uncataloged hard X-ray sources. Until now, the survey dataset has not been used to its full potential due to the complexity associated with its analysis and the lack of easily usable pipelines. Here, we introduce the BatAnalysis python package , a wrapper for HEASoftpy, which provides a modern, open-source pipeline to process and analyze BAT survey data. BatAnalysis allows members of the community to use BAT survey data in more advanced analyses of astrophysical sources including pulsars, pulsar wind nebula, active galactic nuclei, and other known/unknown transient events that may be detected in the hard X-ray band. We outline the steps taken by the python code and exemplify its usefulness and accuracy by analyzing survey data from the Crab Pulsar, NGC 2992, and a previously uncataloged MAXI Transient. The BatAnalysis package allows for ∼ 18 years of BAT survey to be used in a systematic way to study a large variety of astrophysical sources.

Tyler Parsotan↗
NASA NTRSDate not supplied

American Society of Plant Biologists Plenary Symposium Overview Presentation

NASA’s Artemis program in collaboration with international space agencies, and various commercial partners, marks the return of humankind to the Moon. Unlike the Apollo lunar missions from fifty years ago, Artemis will set the stage for the continuous presence of humans on the Moon and pave a path for the journey to Mars and beyond. Plants will be an essential component of habitation systems that will enable humans to thrive on both the lunar and Mars surface, as well as space transit vehicles because of their nutritional and psychological benefits. Furthermore, plants will be valued in environmental control and life support systems because they generate oxygen, remove carbon dioxide, and recycle water and waste. However, an in-depth understanding of how plants and their associated microbial communities adapt to the harsh and confined environment of deep space is essential before they can be effectively used for long-duration space missions. This plenary symposium will address challenges and present potential solutions to growing plants in space. The four speakers will cover a broad range of topics, including mechanistic studies on fern resurgence after asteroid-triggered mass extinction events, artificial photosynthesis for space agriculture, and how the plant microbiome and an understanding of plant-pathogen dynamics in microgravity can guide crop production strategies in space.

Plant Space Biology↗