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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 1,099 records · Page 61
All sourcesNASA NTRSDOE OSTI
NASA NTRS1996

Shock Tunnel Studies of Scramjet Phenomena

Work focussed on a large number of preliminary studies of supersonic combustion in a simple combustion duct - thrust nozzle combination, investigating effects of Mach number, equivalence ratio, combustor divergence, fuel injecting angle and other parameters with an influence on the combustion process. This phase lasted for some three or four years, during which strongest emphasis was placed on responding to the request for preliminary experimental information on high enthalpy effects, to support the technology maturation activities of the NASP program. As the need for preliminary data became less urgent, it was possible to conduct more systematic studies of high enthalpy combustion phenomena, and to initiate other projects aimed at improving the facilities and instrumentation used for studying scramjet phenomena at high enthalpies. The combustion studies were particularly directed towards hypersonic combustion, and to the effects of injecting fuel along the combustion chamber wall. A substantial effort was directed towards a study of the effect of scale on the supersonic combustion process. The influence of wave phenomena (both compression waves and expansion waves) on the realization of thrust from a supersonic combustion process was also investigated. The effect of chemical kinetics was looked into, particularly as it affected the composition of the test flow provided by a ground facility. The effect of injection of the fuel through wall orifices was compared with injection from a strut spanning the stream, and the effect of heating the fuel prior to injection was investigated. Studies of fuel-air mixing by shock impingement were also done, as well as mass spectrometer surveys of a combustion wake. The use of hypersonic nozzles with an expansion tube was investigated. A new method was developed for measuring the forces acting of a model in less than one millisecond. Also included in this report are listings of published journal papers and conference presentations.

Stalker, R. J.↗
NASA NTRS1999

Internet Protocol Enhanced over Satellite Networks

Extensive research conducted by the Satellite Networks and Architectures Branch of the NASA Lewis Research Center led to an experimental change to the Internet's Transmission Control Protocol (TCP) that will increase performance over satellite channels. The change raises the size of the initial burst of data TCP can send from 1 packet to 4 packets or roughly 4 kilobytes (kB), whichever is less. TCP is used daily by everyone on the Internet for e-mail and World Wide Web access, as well as other services. TCP is one of the feature protocols used in computer communications for reliable data delivery and file transfer. Increasing TCP's initial data burst from the previously specified single segment to approximately 4 kB may improve data transfer rates by up to 27 percent for very small files. This is significant because most file transfers in wide-area networks today are small files, 4 kilobytes or less. In addition, because data transfers over geostationary satellites can take 5 to 20 times longer than over typical terrestrial connections, increasing the initial burst of data that can be sent is extremely important. This research along with research from other institutions has led to the release of two new Request for Comments from the Internet Engineering Task Force (IETF, the international body that sets Internet standards). In addition, two studies of the implications of this mechanism were also funded by NASA Lewis.

Ivancic, William D.↗
NASA NTRSDate not supplied

DIP RFI Response Summary Briefing

Digital Information Platform Sub-Project under ATM-X is having a virtual information session to share response summary for the Request for Information (Notice ID: NARC21DIP-RFI). The purpose of this session is to share the valuable inputs from the RFI responses on data & service needs for airspace operations, recommended use cases for DIP collaborative demos, and potential data and technology services that can be provided by the DIP platform through NASA-industry collaboration.

Digital Information Platform↗
DOE OSTI2024

"Traffic Control via Connected and Automated Vehicles: An Open-Road Field Experiment with 100 CAVs"

The CIRCLES project aims to reduce instabilities in traffic flow, which are naturally occurring phenomena due to human driving behavior. These "phantom jams" or "stop-and-go waves,"are a significant source of wasted energy. Toward this goal, the CIRCLES project designed a control system referred to as the MegaController by the CIRCLES team, that could be deployed in real traffic. Our field experiment leveraged a heterogeneous fleet of 100 longitudinally-controlled vehicles as Lagrangian traffic actuators, each of which ran a controller with the architecture described in this paper. The MegaController is a hierarchical control architecture, which consists of two main layers. The upper layer is called Speed Planner, and is a centralized optimal control algorithm. It assigns speed targets to the vehicles, conveyed through the LTE cellular network. The lower layer is a control layer, running on each vehicle. It performs local actuation by overriding the stock adaptive cruise controller, using the stock on-board sensors. The Speed Planner ingests live data feeds provided by third parties, as well as data from our own control vehicles, and uses both to perform the speed assignment. The architecture of the speed planner allows for modular use of standard control techniques, such as optimal control, model predictive control, kernel methods and others, including Deep RL, model predictive control and explicit controllers. Depending on the vehicle architecture, all onboard sensing data can be accessed by the local controllers, or only some. Control inputs vary across different automakers, with inputs ranging from torque or acceleration requests for some cars, and electronic selection of ACC set points in others. The proposed architecture allows for the combination of all possible settings proposed above. Most configurations were tested throughout the ramp up to the MegaVandertest.

Lee, Jonathan↗
NASA NTRS2019

Electronic Departure Approval Requests in ATD-2 Daily Operations

The NASA Airspace Technology Demonstration 2 project is investigating Integrated Arrival-Departure-Surface air traffic management through progressive refinement of a surface air traffic management system fielded at Charlotte-Douglas International Airport. Among the areas under study are departure release-time approval request (APREQ) traffic management initiatives. Scheduling departures at downstream points and complying with approved departure release times helps flights fit smoothly into busy traffic streams. This paper presents a review of APREQ operations and compliance data from daily electronic APREQ negotiations over fourteen months beginning in January 2018. It describes APREQ-compliance improvements observed as the electronic negotiation process has matured and discusses contributing factors, including renegotiation of departure release times.

Call for release↗
DOE OSTI2016

Evaluating Age Effects on HEPA Filter Performance

Nuclear grade high efficiency particulate air (HEPA) filters are routinely employed as the final control element in confinement ventilation systems. The traditional HEPA filter utilizes a pleated filter medium of fibrous glass that has been produced in a manner analogous to manufacturing paper. These filters are the physically weakest element in a containment ventilation system. Containment ventilation systems are designed to condition the air-stream (temperature, relative humidity, moisture, particle size distribution of aerosols, and aerosol concentration) to levels/conditions that fibrous glass HEPA filters can handle. Approximately 6000 nuclear grade HEPA filters are purchased each year for use in the DOE/NNSA complex. Additional filters are purchased for use in commercial nuclear power generation and ventilation systems of other nuclear applications. These filters are designed and tested in accordance with the American Society of Mechanical Engineers (ASME) AG-1 Code Nuclear Air and Gas Treatment. This code establishes design requirements and qualification procedures. Qualification testing of axial flow filters is described in paragraphs 5000 and following of AG-1. The series of qualification tests are intended to describe the operating envelope of HEPA filters and verify the reliability of a filter design. AG-1 qualification also confirms the pedigree of components used in manufacture for that filter design. The collective set of qualification tests establishes the assumed operating envelope for AG-1 filters. The effects of age on HEPA filter performance have been a concern for at least two decades. A combination of physical evaluation of aged filter media and a review of filter failure records resulted in Appendix C of the Nuclear Air Cleaning Handbook (NACH), Determination of HEPA Filter Life. This states that HEPA filters are not to be used beyond 10 years from the date of manufacture. Additionally, filters put into service in locations where they may become wet are to be taken out of service five years from date of manufacture. Filters that have become wet are to be taken out of service immediately. Finally, it should also be pointed out that filters held in Level B storage are subject to the same 10-year service life. Very limited bench-scale testing in the 1990's raised concern that aging HEPA filters do not have the strength to withstand an accident scenario. In May of 1999, the DNFSB released a Technical Report 23 entitled HEPA Filters Used in the Department of Energy's Hazardous Facilities. This report expressed concerns for the potential vulnerability of HEPA filters in vital safety systems. Concerns and uncertainty associated with degradation of HEPA filter performance over time led the DOE sites to limit HEPA filter service life to 10 years from the date of manufacture or five years in cases where filters may become wet. Establishment of a conservative service life needs to be based on data from a structured series of tests comparing the performance envelope of new and aged full-scale filters. A service life that is insufficiently conservative endangers workers and the public. One that is excessively conservative costs can cause hundreds of otherwise unnecessary filter changes. This increases exposure of employees, disrupts facility operations, and increase disposal costs by millions of dollars annually. Conclusive data are needed to resolve uncertainty associated with the damaging effects of aging on durability of HEPA filters. Therefore, this study needs to provide a sufficient body of evidence to allow DOE and site professionals to make prudent decisions. An updated version of ASME AG-1 Section FC included a non-mandatory appendix that would include the DOE guidance for service life of HEPA filters. Balloting of this revision generated significant resistance to inclusion of any kind of service life language citing the lack of supporting experimental data. Efforts to resolve negative votes failed and resistance to acceptance of the language increased. The result has been to not include service language in Section FC and requests to remove it from sections that already include such language. The recent activity of the ASME AG-1 Committee on Nuclear Air and Gas Treatment effectively de-emphasizes following DoE's service life guidelines. The DOE Office of Nuclear Safety under its NSR and D program provided the Mississippi State University Institute for Clean Energy Technology (ICET) finding to initiate a study to determine the effects of aging on AG-1 axial flow filters just prior to actions taken within the AG-1 committee regarding service life. The NSR and D funding facilitated timely development of a national technical working group comprised of members from the regulatory community, DOE complex, and commercial power to resolve uncertainty associated with effects of aging. The Department of Energy Office of Environmental Management (DOE-EM) has been funding the ICET to evaluate the performance envelope for AG-1 HEPA filters. ICET is one of DOE-EM's qualified suppliers. Synergy has been achieved by associating the NSR and D aged filter activities to testing activities evaluating the performance envelopes of separator and separator-less AG-1 HEPA filters funded by DOE-EM. The DOE-EM funded activities establish baseline data for the aged filter study and future EM funding will provide long term support for testing additional aged filters. EM funding of new filters includes analytical evaluation of media tensile strength by thermal analysis to establish baseline values and determine mass loss of moisture resistance and acrylic binders due to use. All of these values can be used for comparison of test results for aged filters. (authors)

07 ISOTOPE AND RADIATION SOURCES↗
NASA NTRS1950

Preliminary Performance Data on Westinghouse Electronic Power Regulator Operating on J34-WE-32 Turbojet Engine in Altitude Wind Tunnel

The behavior of the Westinghouse electronic power regulator operating on a J34-WE-32 turbojet engine was investigated in the NACA Lewis altitude wind tunnel at the request of the Bureau of Aeronautics, Department of the Navy. The object of the program was to determine the, steady-state stability and transient characteristics of the engine under control at various altitudes and ram pressure ratios, without afterburning. Recordings of the response of the following parameters to step changes in power lever position throughout the available operating range of the engine were obtained; ram pressure ratio, compressor-discharge pressure, exhaust-nozzle area, engine speed, turbine-outlet temperature, fuel-valve position, jet thrust, air flow, turbine-discharge pressure, fuel flow, throttle position, and boost-pump pressure. Representative preliminary data showing the actual time response of these variables are presented. These data are presented in the form of reproductions of oscillographic traces.

Ketchum, James R.↗
NASA NTRS1993

Statistical analysis of trigonometric parallaxes

The present project was initiated with two specific medium-term goals: first, to develop a novel approach, based on global modeling and maximum likelihood, to the study of databases of stellar data, with specific attention to the results to be obtained by the Hipparcos mission; and second, to apply and test the methodology developed to existing ground-based data. The long-term goal was of course to integrate the methodology and the ground-based data into a global study of the results of the Hipparcos mission, which were expected to be made available in 1995 or 1996. The closing of the project is due to the recent change of home institution of the PI, who has moved from the University of Illinois to Johns Hopkins University. As a consequence of this move, the three scientists involved in this project will be in close proximity, thereby hopefully improving their ability to collaborate and increasing the productivity of the project. Continued funding for the project has been requested from Johns Hopkins University. This report describes briefly the results obtained so far both on the technical aspect of software development and on the scientific side of applications to existing ground-based data. Significant progress has been made on both counts, with several papers published in (or submitted to) refereed journals and in conference proceedings. Because it is hoped that the project can be successfully continued with NASA support, the report of the progress in each area includes also an assessment of how the current results fit in the expected continuation of the project. Our results to date include: code development (essentially completed); a detailed study of the kinematics and dynamics of stars escaping from the Hyades cluster, relevant to the question of membership in the Hyades; a study of the kinematics and luminosity calibration of nearby dwarfs; an assessment of the quality of the photometry included in the Hipparcos Input Catalog; and two studies of properties of nearby clusters, including a moving-cluster determination of the distance to Praesepe. The bibliography includes three papers submitted to refereed journals, two of which have already been published, and four contributions to conference proceedings. Finally, the work so far has also provided a very good introduction to stellar dynamics and astrometry for an undergraduate student, with educational benefits that had not been foreseen in the original proposal.

Casertano, Stefano↗
DOE OSTI2017

Final Hazard Classification Request for Not More Than 5 Percent Explosives in Solvent Mixtures

This report requests a non-explosive hazard classification of trace explosives in solution. UN Series 1 and 2 explosive hazard classification tests were performed on a simulated worst-case waste stream of five (5) percent by weight of explosive (CL-20) dissolved in a solvent solution (acetone) for transport and storage. The explosive hazard classification test results reported the sample to be non-explosive and the report provides the necessary data for the Department of Transportation to determine and assign the appropriate hazard class for five (5) percent or less of trace explosive in solvent solutions when being shipped and/or stored. Based on the test results, this report requests that the Department of Transportation assign a hazard class of 3, Desensitized explosive liquid, n.o.s. for this type of substance.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Traffic Control via Connected and Automated Vehicles (CAVs): An Open-Road Field Experiment with 100 CAVs

The CIRCLES project aims to reduce instabilities in traffic flow, which are naturally occurring phenomena due to human driving behavior. Also called “phantom jams” or “stop-and-go waves,” these instabilities are a significant source of wasted energy. Toward this goal, the CIRCLES project designed a control system, referred to as the MegaController by the CIRCLES team, that could be deployed in real traffic. Our field experiment, the MegaVanderTest (MVT), leveraged a heterogeneous fleet of 100 longitudinally controlled vehicles as Lagrangian traffic actuators, each of which ran a controller with the architecture described in this article. The MegaController is a hierarchical control architecture that consists of two main layers. The upper layer is called the Speed Planner and is a centralized optimal control algorithm. It assigns speed targets to the vehicles, conveyed through the LTE cellular network. The lower layer is a control layer, running on each vehicle. It performs local actuation by overriding the stock adaptive cruise controller, using the stock onboard sensors. The Speed Planner ingests live data feeds provided by third parties as well as data from our own control vehicles and uses both to perform the speed assignment. The architecture of the Speed Planner allows for the modular use of standard control techniques, such as optimal control, model predictive control (MPC), kernel methods, and others. The architecture of the local controller allows for the flexible implementation of local controllers. Corresponding techniques include deep reinforcement learning (RL), MPC, and explicit controllers. Depending on the vehicle architecture, all onboard sensing data can be accessed by the local controllers or only some. Likewise, control inputs vary across different automakers, with inputs ranging from torque or acceleration requests for some cars to electronic selection of adaptive cruise control (ACC) setpoints in others. The proposed architecture technically allows for the combination of all possible settings proposed previously, that is {Speed Planner algorithms} × {local Vehicle Controller algorithms} × {full or partial sensing} × {torque or speed control}. As a result, most configurations were tested throughout the ramp up to the MegaVandertest (MVT).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2020

Supernova Cosmology with the Dark Energy Survey

This proposal requests supplemental funds to addresses our continued effort to carry out a Type Ia supernova (SN Ia) cosmology analysis with the Dark Energy Survey (DES) data. DES is well underway to discovering and identifying thousands of SN Ia out to a cosmological redshift of z =1.2 over its 5-year survey, and will obtain the best constraints on dark energy and its possible evolution with redshift. We propose to develop two key analysis algorithms and tools that are critical for this achieving the goals: 1) a final photometry pipeline that uses novel techniques to extract unbiased SN fluxes from the images and 2) a robust statistical framework for measuring cosmological parameters from SN Ia light curves with well-characterized systematic uncertainties.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1989

Natural language processing and advanced information management

Integrating diverse information sources and application software in a principled and general manner will require a very capable advanced information management (AIM) system. In particular, such a system will need a comprehensive addressing scheme to locate the material in its docuverse. It will also need a natural language processing (NLP) system of great sophistication. It seems that the NLP system must serve three functions. First, it provides an natural language interface (NLI) for the users. Second, it serves as the core component that understands and makes use of the real-world interpretations (RWIs) contained in the docuverse. Third, it enables the reasoning specialists (RSs) to arrive at conclusions that can be transformed into procedures that will satisfy the users' requests. The best candidate for an intelligent agent that can satisfactorily make use of RSs and transform documents (TDs) appears to be an object oriented data base (OODB). OODBs have, apparently, an inherent capacity to use the large numbers of RSs and TDs that will be required by an AIM system and an inherent capacity to use them in an effective way.

Hoard, James E.↗
NASA NTRS1996

The search for materials to mitigate spacecraft charging

As spacecraft orbit the earth, they encounter a variety of particles and radiation. Charged particles are common enough that a spacecraft can collect substantial charges on its surfaces. If these charges are not bled off, they can accumulate until electrostatic discharges occur between a charged surface and some lower-potential location on the craft. Electrostatic discharge (ESD) is the suspected culprit in a number of spacecraft failures. Silverized Teflon film has become the standard heat-reflecting outer layer of spacecraft because of its flexibility, chemical inertness, and low volatiles content. However, as spacecraft are designed to operate in orbits with greater probability of accumulating enough ions and electrons to create ESD, the Teflon-based thermal control blankets are becoming a liability. Unless stringent (and sometimes burdensome) shielding measures are taken, ESD can upset delicate electronic systems by upsetting or destroying components, interfering with radio signals, garbling internal instructions, and so on. As orbits become higher and more eccentric, as electronics become more sensitive, and as fault-free operation becomes more crucial, it is becoming necessary to find a replacement for silver/Teflon that has comparable strength, flexibility and chemical inertness, as well as a much lower potential for ESD. This is a report of the steps taken toward the goal of selecting a replacement for silver/Teflon during the Summer of 1995. It is a condensation of a much larger report available on request from the author. Three tasks were undertaken. Task 1 was to specify desirable properties for thermal control blankets. The second task was to collect data on materials properties from the literature and organize into a format useful for identifying candidate materials. The third task was to identify candidate materials and begin testing.

Losure, Nancy S.↗
NASA NTRS2004

Extended Operation of Stirling Convertors

A high-efficiency 110 W Stirling Radioisotope Generator 110 (SRG110) is being developed for potential NASA exploration missions. The SRG system efficiency is greater than 20%, making it an attractive candidate power system for deep space missions and unmanned rovers. The Department of Energy SRG110 Project team consists of the System Integrator, Lockheed Martin (LM), Stirling Technology Company (STC), and NASA Glenn Research Center (GRC). One of the GRC roles is to provide Independent Verification and Validation of the Stirling TDC s. At the request of LM, a part of this effort includes the Extended Operation of the TDC s in the dynamically balanced dual-opposed configuration. Performance data of Stirling Convertors over time is required to demonstrate that an SRG110 can meet long-duration mission requirements. A test plan and test system were developed to evaluate TDC s #13 and #14 steady-state performance for a minimum of 5000 hours. Hardware, software and TDC preparation processes were developed to support this test and insure safe, round-the-clock operation of the TDC s. This paper will discuss the design and development, and status of the Extended Operation Test.

Roth, Mary Ellen↗
NASA NTRS2004

Extended Operation of Stirling Convertors

A high-efficiency 110 watt Stirling Radioisotope Generator 110 (SRG110) is being developed for potential NASA exploration missions. The SRG system efficiency is greater than 20%, making it an attractive candidate power system for deep space missions and unmanned rovers. The Department of Energy SRG110 Project team consists of the System Integrator, Lockheed Martin (LM), Stirling Technology Company (STC), and NASA Glenn Research Center (GRC). One of the GRC roles is to provide Independent Verification and Validation of the Stirling TDC's. At the request of LM, a part of this effort includes the extended operation of the TDC's in the dynamically balanced dual-opposed configuration. Performance data of the Stirling Converters over time is required to demonstrate that an SRG110 can meet long-duration mission requirements. A test plan and test system were developed to evaluate TDC's #13 and #14 steady-state performance for a minimum of 5000 hours and insure safe, round-the-clock operation of the TDC's. This paper will discuss the design and development, and status of the Extended Operation Test.

Roth, Mary Ellen↗
NASA NTRS2015

Evolvable Cryogenics (ECRYO) Pressure Transducer Calibration Test

This paper provides a summary of the findings of recent activities conducted by Marshall Space Flight Center's (MSFC) In-Space Propulsion Branch and MSFC's Metrology and Calibration Lab to assess the performance of current "state of the art" pressure transducers for use in long duration storage and transfer of cryogenic propellants. A brief historical narrative in this paper describes the Evolvable Cryogenics program and the relevance of these activities to the program. This paper also provides a review of three separate test activities performed throughout this effort, including: (1) the calibration of several pressure transducer designs in a liquid nitrogen cryogenic environmental chamber, (2) the calibration of a pressure transducer in a liquid helium Dewar, and (3) the calibration of several pressure transducers at temperatures ranging from 20 to 70 degrees Kelvin (K) using a "cryostat" environmental chamber. These three separate test activities allowed for study of the sensors along a temperature range from 4 to 300 K. The combined data shows that both the slope and intercept of the sensor's calibration curve vary as a function of temperature. This homogeneous function is contrary to the linearly decreasing relationship assumed at the start of this investigation. Consequently, the data demonstrates the need for lookup tables to change the slope and intercept used by any data acquisition system. This ultimately would allow for more accurate pressure measurements at the desired temperature range. This paper concludes with a review of a request for information (RFI) survey conducted amongst different suppliers to determine the availability of current "state of the art" flight-qualified pressure transducers. The survey identifies requirements that are most difficult for the suppliers to meet, most notably the capability to validate the sensor's performance at temperatures below 70 K.

Diaz, Carlos E., Jr.↗
NASA NTRS2017

Conjunction Assessment Techniques and Operational Results from the Magnetospheric Multiscale Mission

This paper will describe the results that have been obtained to date during the MMS mission concerning conjunction assessment. MMS navigation makes use of a weak-signal GPS-based system: this allows signals to be received even when MMS is flying above the GPS orbits, producing a highly accurate determination of the four MMS orbits. This data is downlinked to the MMS Mission Operations Center (MOC) and used by the Flight Dynamics Operations Area (FDOA) for both maneuver design and conjunction assessment. The MMS fly in tetrahedron formations around apogee, in order to collect simultaneous particles and fields science data. The original plan was to fly tetrahedra between 10 and 160 km in size; however, after Phase 1a of the mission, the science team requested that smaller sizes be flown if feasible. After analysis (to be detailed in a companion paper), a new minimum size of 7 km was decided upon. Flying at this reduced scale size makes conjunction assessment between the MMS spacecraft even more important: the methods that are used by the MMS FDOA to address this problem will be described in the paper, and a summary given of the previous analyses that went into the development of these techniques. Details will also be given of operational experiences to date. Finally, two CA mitigation maneuver types that have been designed (but never yet required to actually be performed) will also be outlined.

conjunction Assessment↗
NASA NTRS2020

Optical Spectroscopy and X-Ray Observations of the D-Type Symbiotic Star EF Aql

We performed high-resolution optical spectroscopy and X-ray observations of the recently identified Mira-type symbiotic star EF Aql. Based on high-resolution optical spectroscopy obtained with SALT, we determine the temperature (~55 000 K) and the luminosity (~5.3 L⨀) of the hot component in the system. The heliocentric radial velocities of the emission lines in the spectra reveal possible stratification of the chemical elements. We also estimate the mass-loss rate of the Mira donor star. Our Swift observation did not detect EF Aql in X-rays. The upper limit of the X-ray observations is 10(exp -12) erg cm(exp -2) s(exp -1), which means that EF Aql is consistent with the faintest X-ray systems detected so far. Otherwise, we detected it with the UVOT instrument with an average UVM2 magnitude of 14.05. During the exposure, EF Aql became approximately 0.2 UVM2 magnitudes fainter. The periodogram analysis of the V-band data reveals an improved period of 320.4±0.3 d caused by the pulsations of the Mira-type donor star. The spectra are available upon request from the authors.

Symbiotic binary stars↗