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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS2000

Infrared Emission Spectroscopy as a Reliability Tool

In this paper we report on a technique based on infrared emission spectroscopy which has been found to be useful for non-contact measurement of the temperature of a hot spot in the gate channel of a GaAs metal/semiconductor field effect transistor (MESFET). The technique was demonstrated on a powered and un-powered GaAs MESFET attaining a spatial resolution of 0.5 microns. A non-destructive submicron-size spot laser beam provided by an HeNe laser excites an extremely small local area of the gate channel of a GaAs MESFET under various operating conditions. Given the state of the experimental test system, we estimate a spatial resolution of about 0.1 microns and a spectral resolution of about 0. I Angstroms. This provides 15 - 100 times finer spatial resolution than can be obtained using the best passive IR systems available. The temperature resolution (less than 0.02 K/micron) of this technique is depend upon the spectrometer used, and that it can be improved further. The information obtained from this technique can be used to estimate device lifetimes for critical applications and for measurement of channel temperature of devices under actual operating conditions. Another potential use of the novel technique can be as a cost-effective prescreening tool for determining the "hot spot" channel temperature of devices under normal operating conditions which can further improve device design, yield enhancement, and reliable operation

Kim, Q.↗
NASA NTRS1994

Activity Catalog Tool (ACT) user manual, version 2.0

This report comprises the user manual for version 2.0 of the Activity Catalog Tool (ACT) software program, developed by Leon D. Segal and Anthony D. Andre in cooperation with NASA Ames Aerospace Human Factors Research Division, FLR branch. ACT is a software tool for recording and analyzing sequences of activity over time that runs on the Macintosh platform. It was designed as an aid for professionals who are interested in observing and understanding human behavior in field settings, or from video or audio recordings of the same. Specifically, the program is aimed at two primary areas of interest: human-machine interactions and interactions between humans. The program provides a means by which an observer can record an observed sequence of events, logging such parameters as frequency and duration of particular events. The program goes further by providing the user with a quantified description of the observed sequence, through application of a basic set of statistical routines, and enables merging and appending of several files and more extensive analysis of the resultant data.

Segal, Leon D.↗
NASA NTRS2006

ADGS-2100 Adaptive Display and Guidance System Window Manager Analysis

Recent advances in modeling languages have made it feasible to formally specify and analyze the behavior of large system components. Synchronous data flow languages, such as Lustre, SCR, and RSML-e are particularly well suited to this task, and commercial versions of these tools such as SCADE and Simulink are growing in popularity among designers of safety critical systems, largely due to their ability to automatically generate code from the models. At the same time, advances in formal analysis tools have made it practical to formally verify important properties of these models to ensure that design defects are identified and corrected early in the lifecycle. This report describes how these tools have been applied to the ADGS-2100 Adaptive Display and Guidance Window Manager being developed by Rockwell Collins Inc. This work demonstrates how formal methods can be easily and cost-efficiently used to remove defects early in the design cycle.

Whalen, Mike W.↗
NASA NTRS1990

Tribological Properties Of Ceramics

Report reviews adhesion, friction, and micromechanical properties of ceramics - properties increasingly important as more ceramic materials used in bearings, seals, and gears in advanced engines and in cutting tools and extrusion dies. Report considers effects of contaminating surface films, temperature, and chemical interactions. Examines ceramics, in both monolithic and coating form, in contact with themselves, with other harder materials, and with metals.

Miyoshi, Kazuhisa↗
NASA NTRS2016

FEAMAC/CARES Stochastic-Strength-Based Damage Simulation Tool for Ceramic Matrix Composites

Reported here is a coupling of two NASA developed codes: CARES (Ceramics Analysis and Reliability Evaluation of Structures) with the MAC/GMC (Micromechanics Analysis Code/ Generalized Method of Cells) composite material analysis code. The resulting code is called FEAMAC/CARES and is constructed as an Abaqus finite element analysis UMAT (user defined material). Here we describe the FEAMAC/CARES code and an example problem (taken from the open literature) of a laminated CMC in off-axis loading is shown. FEAMAC/CARES performs stochastic-strength-based damage simulation response of a CMC under multiaxial loading using elastic stiffness reduction of the failed elements.

composite structures↗
NASA NTRS2015

Stochastic-Strength-Based Damage Simulation Tool for Ceramic Matrix Composite

Reported here is a coupling of two NASA developed codes: CARES (Ceramics Analysis and Reliability Evaluation of Structures) with the MAC/GMC (Micromechanics Analysis Code/ Generalized Method of Cells) composite material analysis code. The resulting code is called FEAMAC/CARES and is constructed as an Abaqus finite element analysis UMAT (user defined material). Here we describe the FEAMAC/CARES code and an example problem (taken from the open literature) of a laminated CMC in off-axis loading is shown. FEAMAC/CARES performs stochastic-strength-based damage simulation response of a CMC under multiaxial loading using elastic stiffness reduction of the failed elements.

ceramic matrix composites↗
NASA NTRS2010

Portable Diagnostics Technology Assessment for Space Missions: General Technology Capabilities for NASA Exploration Missions - Part 1

The changes in the scope of NASA s mission in the coming decade are profound and demand nimble, yet insightful, responses. On-board clinical and environmental diagnostics must be available for both mid-term lunar and long-term Mars exploration missions in an environment marked by scarce resources. Miniaturization has become an obvious focus. Despite solid achievements in lab-based devices, broad-based, robust tools for application in the field are not yet on the market. The confluence of rapid, wide-ranging technology evolution and internal planning needs are the impetus behind this work. This report presents an analytical tool for the ongoing evaluation of promising technology platforms based on mission- and application-specific attributes. It is not meant to assess specific devices, but rather to provide objective guidelines for a rational down-select of general categories of technology platforms. In this study, we have employed our expertise in the microgravity operation of fluidic devices, laboratory diagnostics for space applications, and terrestrial research in biochip development. A rating of the current state of technology development is presented using the present tool. Two mission scenarios are also investigated: a 30-day lunar mission using proven, tested technology in 5 years; and a 2- to 3-year mission to Mars in 10 to 15 years.

Nelson, Emily S.↗
NASA NTRS2008

A System Trade Study of Remote Infrared Imaging for Space Shuttle Reentry

A trade study reviewing the primary operational parameters concerning the deployment of imaging assets in support of the Hypersonic Thermodynamic Infrared Measurements (HYTHIRM) project was undertaken. The objective was to determine key variables and constraints for obtaining thermal images of the Space Shuttle orbiter during reentry. The trade study investigated the performance characteristics and operating environment of optical instrumentation that may be deployed during a HYTHIRM data collection mission, and specified contributions to the Point Spread Function. It also investigated the constraints that have to be considered in order to optimize deployment through the use of mission planning tools. These tools simulate the radiance modeling of the vehicle as well as the expected spatial resolution based on the Orbiter trajectory and placement of land based or airborne optical sensors for given Mach numbers. Lastly, this report focused on the tools and methodology that have to be in place for real-time mission planning in order to handle the myriad of variables such as trajectory ground track, weather, and instrumentation availability that may only be known in the hours prior to landing.

Schwartz, Richard J.↗
NASA NTRS2019

Simulating Fleet Noise for Notional UAM Vehicles and Operations in New York

This paper presents the results of systems-level simulations using Metrosim that were conducted for notional Urban Air Mobility (UAM)-style vehicles analyzed for two different scenarios for New York (NY). UAM is an aviation industry term for passenger or cargo-carrying air transportation services, which are often automated, operating in an urban/city environment. UAM-style vehicles are expected to use vertical takeoff and landing with fixed wing cruise flight. Metrosim is a metroplex-wide route and airport planning tool that can also be used in standalone mode as a simulation tool. The scenarios described and reported in this paper were used to evaluate a fleet noise prediction capability for this tool. The work was a collaborative effort between the National Aeronautics and Space Administration (NASA), Intelligent Automation, Inc (IAI), and the Port Authority of New York and New Jersey (PANYNJ). One scenario was designed to represent an expanded air-taxi operation from existing helipads around Manhattan to the major New York airports. The other case represented a farther term vision case with commuters using personal air vehicles to hub locations just outside New York, with an air-taxi service running frequent connector trips to a few key locations inside Manhattan. For both scenarios, the trajectories created for the entire fleet were passed to the Aircraft Environmental Design Tool (AEDT) to generate Day-Night Level (DNL) noise contours for inspection. Without data for actual UAM vehicles available, surrogate AEDT empirical Noise-Power-Distance (NPD) tables used a similar sized current day helicopter as the Baseline, and a version of that same data linearly scaled as a first guess at possible UAM noise data. Details are provided for each of the two scenario configurations, and the output noise contours are presented for the Baseline and reduced noise DNL cases.

Glaab, Patricia↗
NASA NTRS2007

Anvil Tool in the Advanced Weather Interactive Processing System

Meteorologists from the 45th Weather Squadron (45 WS) and Spaceflight Meteorology Group (SMG) have identified anvil forecasting as one of their most challenging tasks when predicting the probability of violations of the lightning Launch Commit Criteria and Space Shuttle Flight Rules. As a result, the Applied Meteorology Unit (AMU) created a graphical overlay tool for the Meteorological Interactive Data Display Systems (MIDDS) to indicate the threat of thunderstorm anvil clouds, using either observed or model forecast winds as input. In order for the Anvil Tool to remain available to the meteorologists, the AMU was tasked to transition the tool to the Advanced Weather interactive Processing System (AWIPS). This report describes the work done by the AMU to develop the Anvil Tool for AWIPS to create a graphical overlay depicting the threat from thunderstorm anvil clouds. The AWIPS Anvil Tool is based on the previously deployed AMU MIDDS Anvil Tool. SMG and 45 WS forecasters have used the MIDDS Anvil Tool during launch and landing operations. SMG's primary weather analysis and display system is now AWIPS and the 45 WS has plans to replace MIDDS with AWIPS. The Anvil Tool creates a graphic that users can overlay on satellite or radar imagery to depict the potential location of thunderstorm anvils one, two, and three hours into the future. The locations are based on an average of the upper-level observed or forecasted winds. The graphic includes 10 and 20 nm standoff circles centered at the location of interest, in addition to one-, two-, and three-hour arcs in the upwind direction. The arcs extend outward across a 30 degree sector width based on a previous AMU study which determined thunderstorm anvils move in a direction plus or minus 15 degrees of the upper-level (300- to 150-mb) wind direction. This report briefly describes the history of the MIDDS Anvil Tool and then explains how the initial development of the AWIPS Anvil Tool was carried out. After testing was performed by SMG, 45 WS, and AMU, a number of needed improvements were identified. A bug report document was created that showed the status of each bug and desired improvement. This report lists the improvements that were made to increase the accuracy and user-friendliness of the tool. Final testing was carried out and documented and then the final version of the software and Users Guide was provided to SMG and the 45 WS. Several possible future improvements to the tool are identified that would increase the flexibility of the tool. This report contains a brief history of the development of the Anvil Tool in MIDDS, and then describes the transition and development of software to AWIPS.

Barrett, Joe, III↗
NASA NTRSDate not supplied

Simplifying Requirements Formalization for Resource-Constrained Mission-Critical Software

Developing critical software requires adherence to rigorous software development practices, such as formal requirement specification and verification. Despite their importance, such practices are often considered as complex and challenging tasks that require a strong formal methods background. In this paper, we present our work on simplifying the formal requirements specification experience for resource-constrained mission critical software through the use of structured natural language. To this end, we connect NASA’s FRET, a formal requirement elicitation and authoring tool with the Shelley model checking framework for MicroPython code. We report our experience on using these tools to specify requirements and analyze code from the NASA Ames PHALANX exploration concept.

PHALANX exploration concept↗
NASA NTRS1979

Design, fabrication, test, and evaluation of a prototype 150-foot long composite wind turbine blade

The design, fabrication, testing, and evaluation of a prototype 150 foot long composite wind turbine blade is described. The design approach and material selection, compatible with low cost fabrication methods and objectives, are highlighted. The operating characteristics of the blade during rotating and nonrotating conditions are presented. The tensile, compression, and shear properties of the blade are reported. The blade fabrication, tooling, and quality assurance are discussed.

Gewehr, H. W.↗
NASA NTRS1983

A data base processor semantics specification package

A Semantics Specification Package (DBPSSP) for the Intel Data Base Processor (DBP) is defined. DBPSSP serves as a collection of cross assembly tools that allow the analyst to assemble request blocks on the host computer for passage to the DBP. The assembly tools discussed in this report may be effectively used in conjunction with a DBP compatible data communications protocol to form a query processor, precompiler, or file management system for the database processor. The source modules representing the components of DBPSSP are fully commented and included.

Fishwick, P. A.↗
NASA NTRS1993

Development of code evaluation criteria for assessing predictive capability and performance

Computational Fluid Dynamics (CFD), because of its unique ability to predict complex three-dimensional flows, is being applied with increasing frequency in the aerospace industry. Currently, no consistent code validation procedure is applied within the industry. Such a procedure is needed to increase confidence in CFD and reduce risk in the use of these codes as a design and analysis tool. This final contract report defines classifications for three levels of code validation, directly relating the use of CFD codes to the engineering design cycle. Evaluation criteria by which codes are measured and classified are recommended and discussed. Criteria for selecting experimental data against which CFD results can be compared are outlined. A four phase CFD code validation procedure is described in detail. Finally, the code validation procedure is demonstrated through application of the REACT CFD code to a series of cases culminating in a code to data comparison on the Space Shuttle Main Engine High Pressure Fuel Turbopump Impeller.

Lin, Shyi-Jang↗