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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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7 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2018

The Behavior, Constraint, and Scenario (BeCoS) Tool: A Web-Based Software Application for Modeling Behaviors and Scenarios

The Behavior, Constraint, and Scenario (BeCoS) tool has been developed to allow engineers to specify system and component behaviors. The tool is a web application that is developed in JavaScript and uses the React framework for the user interface and Redux for maintaining application state. The foundation of the tool is its underlying ontology, which expands upon a previously-defined behavior ontology with a scenario ontology. The behavior ontology includes elements like behaving elements, state variables, parameters, and constraints, while the scenario ontology includes core constructs like activities, temporal constraints, and timepoints. BeCoS allows users to easily create behaving elements and to specify their state variables, parameters, state machines, and constraints. BeCoS also allows users to develop temporal constraint networks that specify constraints on component states over time. BeCoS is a prototype tool that has been deployed and tested by systems engineers on the Europa Clipper project, which generated several use cases and helped steer its current developmental effort. By enabling systems engineers to specify behavior in a semantically-rigorous manner, BeCoS is an enabling technology for analyses that previously could not be performed, and when exporting its model to other tools, allows for consistent behavior models to be used.

Ingham, Michel D.↗
NASA NTRS2018

The Behavior, Constraint, and Scenario (BeCoS) Tool: A Web-Based Software Application for Modeling Behaviors and Scenarios

The Behavior, Constraint, and Scenario (BeCoS) tool has been developed to allow engineers to specify system and component behaviors. The tool is a web application that is developed in JavaScript and uses the React framework for the user interface and Redux for maintaining application state. The foundation of the tool is its underlying ontology, which expands upon a previously-defined behavior ontology with a scenario ontology. The behavior ontology includes elements like behaving elements, state variables, parameters, and constraints, while the scenario ontology includes core constructs like activities, temporal constraints, and timepoints. BeCoS allows users to easily create behaving elements and to specify their state variables, parameters, state machines, and constraints. BeCoS also allows users to develop temporal constraint networks that specify constraints on component states over time. BeCoS is a prototype tool that has been deployed and tested by systems engineers on the Europa Clipper project, which generated several use cases and helped steer its current developmental effort. By enabling systems engineers to specify behavior in a semantically-rigorous manner, BeCoS is an enabling technology for analyses that previously could not be performed, and when exporting its model to other tools, allows for consistent behavior models to be used.

Inghams, Michel D.↗
DOE OSTI2020

Materials Data on BeCo by Materials Project

BeCo is Tetraauricupride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Be is bonded in a body-centered cubic geometry to eight equivalent Co atoms. All Be–Co bond lengths are 2.24 Å. Co is bonded in a body-centered cubic geometry to eight equivalent Be atoms.

36 MATERIALS SCIENCE↗
NASA NTRS1973

Trajectory description

The Mariner 9 spacecraft was launched by an Atlas/Centaur launch vehicle (AC-23) on a direct-ascent trajectory from the Air Force Eastern Test Range (AFETR) launch complex 36B on May 30, 1971. Liftoff occurred at 22 h 23 min 04.5 s GMT, slightly more than 6 min after the opening of a 60-min launch window. The vehicle rose vertically for approximately 15 s, during which time, a programmed roll to a launch azimuth of 92.74 deg was performed. After the initial vertical rise, the vehicle, guided by the open-loop Atlas autopilot, began to pitch over into a zero-lift trajectory. The first of three main powered phases was terminated by booster engine cutoff (BECO) at 22 h 25 min 35.5 s. After the Atlas booster engine package was jettisoned 3 s later, the flight continued under the power of the Atlas sustainer engine and guided by the Centaur guidance system operating in a closed-loop mode.

Webb, W. A.↗
NASA NTRS1994

Theoretical Study of Electron Scattering By Small Clusters and Adsorbates

Current interest in clusters stems from their role as novel materials as well as a possible extension of cluster results to bulk systems. Experimental investigations on clusters have been carried out using laser spectroscopy, microwave spectroscopy, heavy-particle collisions, as well as electron collisions with earlier experimental work on electron attachment and ionization having been reviewed previously. Recently, Mark and coworkers studied the decay channels of cluster ions following electron impact ionization. Rauth et al. reported the formation of the superhalogen ion SF7(-) and other nonstoichiometric cluster ions in their study of electron attachment to SF6 clusters. Kresin et al. measured the absolute electron-impact depletion cross section of metal clusters Na8, Na(20), and Na(40). They found that the inelastic scattering cross section increased with cluster size and was considerably greater than the hard sphere collision cross sections. They hypothesized that electron attachment and collision-induced fragmentation were the dominant physical processes responsible for this effect. For the two smaller clusters, they also found a sharp increase in the cross section near threshold. Most theoretical studies of clusters have been devoted to their electronic structures, vibrational relaxation, and predissociation while investigations of electron scattering from clusters has been lacking. In view of this, we recently undertook an ab initio study of electron scattering from small Be clusters and BeCO. Beryllium was chosen because it is readily amenable to ab t'nitio calculations. Moreover, the electronic structure of Be clusters has been studied extensively, showing that the Be-Be bond is relatively weak in comparison with a normal chemical bond. Our investigation focuses on how the cross sections change with cluster size and geometry. The range of energy studied, 0.05 - 5.0 eV, is chosen because of the ubiquitous resonance in the low-energy scattering of Be. Hence it can be determined if it is possible, as a consequence of the weaker bonds in the Be clusters, to identify the atomic origin of the cluster resonance.

Huo, Winifred M.↗
NASA NTRS1995

Theoretical Study of Low-Energy Electron-Molecule Collisions

Polarized studies of electron collisions with carbon tetrafluoride and beryllium carbonyl are reported. In the e-CF4 study, the resonance structure between 8-9 eV is shown to be a superposition of the T2- and A1-symmetry shape resonances. The unequivocal assignment of this feature as a double-resonance structure clarifies certain discrepancies in previous attempts to ascribe the 8-9 eV feature to a shape resonance in one or another partial channel and explains the sensitivities found in the fragment ion production in the resonance region. The Be-CO system is chosen as a prototypical example of an absorbate-substrate interaction. To understand how bonding with the substrate affects the CO resonance, electron collision with two states of BeCO are studied, one with a very weak van der Waals bond and the other, with a normal chemical bond. It is shown that the nature of the Be-CO bond has strong effects on the cross section feature.

Huo, Winfred M.↗