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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 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
NASA NTRS1996

Continued Development of Expert System Tools for NPSS Engine Diagnostics

The objectives of this grant were to work with previously developed NPSS (Numerical Propulsion System Simulation) tools and enhance their functionality; explore similar AI systems; and work with the High Performance Computing Communication (HPCC) K-12 program. Activities for this reporting period are briefly summarized and a paper addressing the implementation, monitoring and zooming in a distributed jet engine simulation is included as an attachment.

Lewandowski, Henry↗
NASA NTRS2006

XBoard: A Framework for Integrating and Enhancing Collaborative Work Practices

Teams typically collaborate in different modes including face-to-face meetings, meetings that are synchronous (i. e. require parties to participate at the same time) but distributed geographically, and meetings involving asynchronously working on common tasks at different times. The XBoard platform was designed to create an integrated environment for creating applications that enhance collaborative work practices. Specifically, it takes large, touch-screen enabled displays as the starting point for enhancing face-to-face meetings by providing common facilities such as whiteboarding/electronic flipcharts, laptop projection, web access, screen capture and content distribution. These capabilities are built upon by making these functions inherently distributed by allowing these sessions to be easily connected between two or more systems at different locations. Finally, an information repository is integrated into the functionality to provide facilities for work practices that involve work being done at different times, such as reports that span different shifts. The Board is designed to be extendible allowing customization of both the general functionality and by adding new functionality to the core facilities by means of a plugin architecture. This, in essence, makes it a collaborative framework for extending or integrating work practices for different mission scenarios. XBoard relies heavily on standards such as Web Services and SVG, and is built using predominately Java and well-known open-source products such as Apache and Postgres. Increasingly, organizations are geographically dispersed, and rely on "virtual teams" that are assembled from a pool of various partner organizations. These organizations often have different infrastructures of applications and workflows. The XBoard has been designed to be a good partner in these situations, providing the flexibility to integrate with typical legacy applications while providing a standards-based infrastructure that is readily accepted by most organizations. The XBoard has been used on the Mars Exploration Rovers mission at JPL, and is currently being used or considered for use in pilot projects at Johnson Space Center (JSC) Mission Control, the University of Arizona Lunar and Planetav Laboratory (Phoenix Mars Lander), and MBART (Monterey Bay Aquarium Research Institute).

Shab, Ted↗
NASA NTRS1991

Test functions for the moment method which yield the minimum mean square error

The method of moments has found extensive applications in the solution of a wide class of electromagnetic problems. Additionally, there are a number of basis functions which have found favor and with them different types of testing methods. This work examines the selection of test functions, given a selected set of basis functions, which serve to minimize the mean square error. These test functions will guarantee equal or lesser error compared with any other test function. Additionally, these test functions provide a monotonic improvement of the approximation as the increase in the order of the system. Hence while these test functions require the application of the differential or integral operator one additional time, they provide an absolute lower bound to the mean square error in the approximation and a means to systematically improve accuracy with each increase in the order of the unknowns.

Shamansky, H.↗
NASA NTRS2014

Human-Automation Cooperation for Separation Assurance in Future NextGen Environments

A 2012 Human-In-The-Loop air traffic control simulation investigated a gradual paradigm-shift in the allocation of functions between operators and automation. Air traffic controllers staffed five adjacent high-altitude en route sectors, and during the course of a two-week experiment, worked traffic under different function-allocation approaches aligned with four increasingly mature NextGen operational environments. These NextGen time-frames ranged from near current-day operations to nearly fully-automated control, in which the ground systems automation was responsible for detecting conflicts, issuing strategic and tactical resolutions, and alerting the controller to exceptional circumstances. Results indicate that overall performance was best in the most automated NextGen environment. Safe operations were achieved in this environment for twice todays peak airspace capacity, while being rated by the controllers as highly acceptable. However, results show that sector operations were not always safe; separation violations did in fact occur. This paper will describe in detail the simulation conducted, as well discuss important results and their implications.

air traffic control↗
NASA NTRS2014

A Closer Look at Automation Behavior During a Human-in-the-Loop Simulation

A 2012 Human-In-The-Loop air traffic control simulation investigated a gradual paradigm-shift in the allocation of functions between operators and automation. Air traffic controllers staffed five adjacent high-altitude en route sectors, and during the course of a two-week experiment, worked traffic under four different function allocation concepts aligned with increasingly mature NextGen operational environments. These NextGen time-frames ranged from near current-day operations to nearly fully-automated control, in which the ground systems automation was responsible for detecting conflicts, issuing strategic and tactical resolutions, and alerting controllers to exceptional circumstances. This paper continues the investigations reported in previous publications. Analyses of data surrounding the conflict-resolution task serve as the context in which we investigate the interactions between controllers and the automation.

Human-Automation Interaction↗
NASA NTRS1975

Television systems for remote manipulation

An analytical and experimental study was conducted to specify a video system for remote manipulation in space. An operator function analysis identified two basic characteristics, work volume and element relationship, which define four manipulation tasks chosen for examination. A visual function analysis developed a set of elemental scene parameters which grouped the visual dimensions into major areas of influence. Simulation testing was conducted with a four degree-of-freedom motion frame which allowed an operator to perform the manipulation tasks. Four video systems were included in the simulation testing: a black and white and a color monoscopic system, a stereoscopic system, and a black and white two-view system. A sequential experimental plan first provided an overall analysis of the effects of tasks, scene parameters, and video systems. This was followed by a detailed experimental examination of the critical dimensions identified in the first experiment. Results are discussed in terms of a recommended TV system.

Crooks, W. H.↗
NASA NTRSDate not supplied

Understanding the Impact of High-Velocity Dust Due to Lunar Landings

Evidence from earlier landings by Surveyor and Apollo have provided ample evidence regarding the dangers of high-velocity ejecta. These dangers include the generation of dust that settle on equipment, posing a hazard to equipment fol-lowing landing, the sandblasting of objects near the landing site, and the spead of high-velocity dust over the entire lunar surface and in lunar orbit that may remain for long periods of time. Recent work has provided valuable insight into the behavior and nature of the dust as a function of lander size, but further work is needed to gain a better understanding of the initial trajectories of this high- velocity dust.

lunar↗
NASA NTRS1988

Functional reasoning in diagnostic problem solving

This work is one facet of an integrated approach to diagnostic problem solving for aircraft and space systems currently under development. The authors are applying a method of modeling and reasoning about deep knowledge based on a functional viewpoint. The approach recognizes a level of device understanding which is intermediate between a compiled level of typical Expert Systems, and a deep level at which large-scale device behavior is derived from known properties of device structure and component behavior. At this intermediate functional level, a device is modeled in three steps. First, a component decomposition of the device is defined. Second, the functionality of each device/subdevice is abstractly identified. Third, the state sequences which implement each function are specified. Given a functional representation and a set of initial conditions, the functional reasoner acts as a consequence finder. The output of the consequence finder can be utilized in diagnostic problem solving. The paper also discussed ways in which this functional approach may find application in the aerospace field.

Sticklen, Jon↗
NASA NTRS2011

Project Summary Report

The project, being the development of resource management applications, consisted entirely of my own effort. From deliverable requirements provided by my mentor, and some functional requirement additions generated through design reviews, It was my responsibility to implement the requested features as well as possible, given the resources available. For the most part development work consisted of database programming and functional testing using real resource data. Additional projects I worked on included some firing room console training, configuring the new NE-A microcontroller development lab network, mentoring high school CubeSat students, and managing the NE interns' component of the mentor appreciation ceremony.

Upchurch, Christopher↗
NASA NTRS2007

Working With the Wave Equation in Aeroacoustics: The Pleasures of Generalized Functions

The theme of this paper is the applications of generalized function (GF) theory to the wave equation in aeroacoustics. We start with a tutorial on GFs with particular emphasis on viewing functions as continuous linear functionals. We next define operations on GFs. The operation of interest to us in this paper is generalized differentiation. We give many applications of generalized differentiation, particularly for the wave equation. We discuss the use of GFs in finding Green s function and some subtleties that only GF theory can clarify without ambiguities. We show how the knowledge of the Green s function of an operator L in a given domain D can allow us to solve a whole range of problems with operator L for domains situated within D by the imbedding method. We will show how we can use the imbedding method to find the Kirchhoff formulas for stationary and moving surfaces with ease and elegance without the use of the four-dimensional Green s theorem, which is commonly done. Other subjects covered are why the derivatives in conservation laws should be viewed as generalized derivatives and what are the consequences of doing this. In particular we show how we can imbed a problem in a larger domain for the identical differential equation for which the Green s function is known. The primary purpose of this paper is to convince the readers that GF theory is absolutely essential in aeroacoustics because of its powerful operational properties. Furthermore, learning the subject and using it can be fun.

Farassat, F.↗
NASA NTRS2018

Cumulative Distribution of Ballistic Impact Failures of Common Twisted-Pair Data Cables at Orbital Speeds

Data wire cable runs are a significant presence on the exterior of the International Space Station (ISS), and continued ISS mission support requires detailed assessment of cables due to micrometeoroid and orbit debris (MMOD) impact. These data wire cables are twisted-pair cables consisting of two 22AWG stranded conductors and fillers inside a tight fitting braided copper shield. The copper shield and its contents are covered with a jacket that has a nominal outer diameter of 3.76 mm and beta-cloth tape. The ISS engineering community has identified two loss-of-function mechanisms for these cables: open circuits due to severed conductors within the cable, and short circuits due to contact between conductors or grounded components. As these data cables are low power systems, short circuits are not expected to burn away the contact, so both open and short circuits are considered permanent loss-of-function for the cable. A total of ninety-seven impact experiments have been performed into these cables to develop a statistical model for the failure of these cables to be used in reliability studies. The experimental work has yielded cumulative distribution functions for these cables for steel and aluminum components of the orbital debris environment at representative speeds and impact obliquities.

Miller, Joshua E.↗
NASA NTRS2005

Towards a Functionally-Formed Air Traffic System-of-Systems

Incremental improvements to the national aviation infrastructure have not resulted in sufficient increases in capacity and flexibility to meet emerging demand. Unfortunately, revolutionary changes capable of substantial and rapid increases in capacity have proven elusive. Moreover, significant changes have been difficult to implement, and the operational consequences of such change, difficult to predict due to the system s complexity. Some research suggests redistributing air traffic control functions through the system, but this work has largely been dismissed out of hand, accused of being impractical. However, the case for functionally-based reorganization of form can be made from a theoretical, systems perspective. This paper investigates Air Traffic Management functions and their intrinsic biases towards centralized/distributed operations, grounded in systems engineering and information technology theories. Application of these concepts to a small airport operations design is discussed. From this groundwork, a robust, scalable system transformation plan may be made in light of uncertain demand.

Conway, Sheila R.↗
NASA NTRS1986

Far-infrared investigation of the Taurus star-forming region using the IRAS database

The Infrared Astronomical Satellite (IRAS) has given us the first completely unbiased sky-survey in the far-infrared with wavebands centered at 12, 25, 60 and 100 microns. The Taurus-Auriga complex was selected as the first molecular cloud to be investigated in this study. The Taurus clouds were defined as lying between 04h and 05h in R.A. and +16 to +31 degrees in Dec., then the IRAS point-source catalogue was searched for sources with good or moderate quality fluxes in all three of the shortest IRAS bands. The sources which were selected in this way were then classified into subgroups according to their IRAS colors. Taurus is generally believed to be an area of low-mass star formation, having no luminous O-B associations within or near to the cloud complex. Once field stars, galaxies and planetary nebulae had been removed from the sample only the molecular cloud cores, T Tauri stars and a few emission-line A and B stars remained. The great majority of these objects are pre-main sequence in nature and, as stated by Chester (1985), main sequence stars without excess far-infrared emission would only be seen in Taurus if their spectral types were earlier than about A5 and then not 25 microns. By choosing our sample in this way we are naturally selecting the hotter and thus more evolved sources. To counteract this, the molecular cloud core-criterion was applied to soruces with good or moderate quality flux at 25, 60 and 100 microns, increasing the core sample by about one third. The candidate protostar B335 is only detected by IRAS at 60 and 100 microns while Taurus is heavily contaminated by cirrus at 100 microns. This means that detection at 25 microns is also required with those at 60 and 100 microns to avoid confusing a ridge of cirrus with a genuine protostar. The far-infrared luminosity function of these sources is then calculated and converted to the visual band by a standard method to compare with the field star luminosity function of Miller and Scalo. The eventual aim of this work is to obtain far-infrared luminosity functions for a number of molecular clouds which are known to be forming low-mass stars and to investigate how the slope is affected by changes in the density and turbulence of material.

Hughes, J. D.↗
NASA NTRS1990

Inhomogeneous deformation in INCONEL 718 during monotonic and cyclic loadings

The paper concentrates on the relation between microstructural observations of the dislocation structures and the macroscopic deformation responses of both aged and homogenized precipitate-hardened alloys at room temperature. The deformation responses are compared to the cyclic deformation response of an aged precipitate-hardened alloy. Early in the deformation, one deformation band per grain and little evidence of work hardening are observed; with increased deformation, work hardening begins, more bands nucleate, and their spacing becomes similar to that in the aged material. It is pointed out that the degree of coarseness of inhomogeneous deformation is not a result of a softening process within the bands due to precipitate shearing, but it is a function of the amount of work hardening within the bands.

Worthem, D. W.↗
NASA NTRS1975

Vestibular function in the space environment

The present work presents new results about the interdependence of optical illusory sensations and eye movements in man. To establish to what degree certain illusions previously obtained during centrifugation and parabolic flight can be explained by eye movements and by neuronal integration in the brain, real eye movements were measured as they occurred in the dark without optical fixation, during rectilinear accelerations on the ground, and during weightlessness in parabolic flight. Results provide valuable insight into normal vestibular function as well as resolution of within-the-eye and behind-the-eye contributions to the above illusions.

Von Baumgarten, R. J.↗