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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 1,621 records · Page 90
All sourcesNASA NTRSDOE OSTI
NASA NTRS2010

A New Representative for Small-Body Gravity Estimation

One of the options proposed in the 2009 Review of the U. S. Human Spaceflight Plans Committee calls for the consideration of robotic and human missions to asteroids. Beginning in 2000, the NEAR Shoemaker spacecraft inserted into orbit about the asteroid 433 Eros, and studied it for a year before landing. The Hayabusa satellite journeyed to 25143 Itokawa, and operated in a proximity of the asteroid for several months before landing to collect a return sample. Additionally, the DAWN satellite, which was launched in 2007, will explore the dwarf-planet Ceres and the asteroid 4 Vesta in the next three years. These are just several examples of current interests in exploring asteroids. In this paper, we explore an alternative for estimating the gravity field of a small body using observations of an orbiting satellite. Our approach uses two new mathematical tools, the quadratures (on a sphere) invariant under the icosahedral group, and a multiresolution representation of the gravity potential. With the near optimal quadratures on the sphere, we minimize the number of parameters needed to recover a function. Also, instead of estimating the coefficients of the spherical harmonics, the new quadratures allow us to estimate directly the values of the gravity field since they offer an analogue of the Lagrange-type interpolation.

Jones, Brandon A.↗
NASA NTRS2010

Water Membrane Evaporator

A water membrane evaporator (WME) has been conceived and tested as an alternative to the contamination-sensitive and corrosion-prone evaporators currently used for dissipating heat from space vehicles. The WME consists mainly of the following components: An outer stainless-steel screen that provides structural support for the components mentioned next; Inside and in contact with the stainless-steel screen, a hydrophobic membrane that is permeable to water vapor; Inside and in contact with the hydrophobic membrane, a hydrophilic membrane that transports the liquid feedwater to the inner surface of the hydrophobic membrane; Inside and in contact with the hydrophilic membrane, an annular array of tubes through which flows the spacecraft coolant carrying the heat to be dissipated; and An inner exclusion tube that limits the volume of feedwater in the WME. In operation, a pressurized feedwater reservoir is connected to the volume between the exclusion tube and the coolant tubes. Feedwater fills the volume, saturates the hydrophilic membrane, and is retained by the hydrophobic membrane. The outside of the WME is exposed to space vacuum. Heat from the spacecraft coolant is conducted through the tube walls and the water-saturated hydrophilic membrane to the liquid/vapor interface at the hydrophobic membrane, causing water to evaporate to space. Makeup water flows into the hydrophilic membrane through gaps between the coolant tubes.

Ungar, Eugene K.↗
NASA NTRS2012

Aerothermal Testing of Woven TPS Ablative Materials

Woven Thermal Protection Systems (WTPS) is a new TPS concept that is funded by NASAs Office of the Chief Technologist (OCT) Game Changing Division. The WTPS project demonstrates the potential for manufacturing a variety of TPS materials capable of wide ranging performances demanded by a spectrum of solar system exploration missions. Currently, missions anticipated to encounter heat fluxes in the range of 1500 4000 Watts per square centimeter are limited to using one proven material fully dense Carbon Phenolic. However, fully dense carbon phenolic is only mass efficient at heat fluxes greater than 4000 Watts per square centimeter, and current mission designs suffer this mass inefficiency for lack of an alternative mid-density TPS. WTPS not only bridges this gap but also offers a replacement for carbon phenolic, which itself requires a significant and costly redevelopment effort to re-establish its capability for use in the high heat flux missions recently prioritized in the NRC Decadal survey, including probe missions to Venus, Saturn and Neptune. This poster will summarize some recent arc jet testing to evaluate the performance of WTPS. Both mid density and fully dense WTPS test results will be presented and results compared to heritage carbon phenolic where applicable.

Stackpoole, Mairead↗
NASA NTRS2010

Hypergolic Propellant Destruction Evaluation Cost Benefit Analysis

At space vehicle launch sites such as Vandenberg Air Force Base (VAFB), Cape Canaveral Air Force Station (CCAFS) and Kennedy Space Center (KSC), toxic vapors and hazardous liquid wastes result from the handling of commodities (hypergolic fuels and oxidizers), most notably from transfer operations where fuel and oxidizer are transferred from bulk storage tanks or transfer tankers to space launch vehicles. During commodity transfer at CCAFS and KSC, wet chemical scrubbers (typically containing four scrubbing towers) are used to neutralize fuel saturated vapors from vent systems on tanks and tanker trailers. For fuel vapors, a citric acid solution is used to scrub out most of the hydrazine. Operation of both the hypergolic fuel and oxidizer vapor scrubbers generates waste scrubber liquor. Currently, scrubber liquor from the fuel vapor scrubber is considered non-hazardous. The scrubber liquor is defined as spent citric acid scrubber solution; the solution contains complexed hydrazine I methylhydrazine and is used to neutralize nonspecification hypergolic fuel generated by CCAFS and KSC. This project is a collaborative effort between Air Force Space Command (AFSPC), Space and Missile Center (SMC), the CCAFS, and National Aeronautics and Space Administration (NASA) to evaluate microwave destruction technology for the treatment of non-specification hypergolic fuel generated at CCAFS and KSC. The project will capitalize on knowledge gained from microwave treatment work being accomplished by AFSPC and SMC at V AFB. This report focuses on the costs associated with the current non-specification hypergolic fuel neutralization process (Section 2.0) as well as the estimated costs of operating a mobile microwave unit to treat non-specification hypergolic fuel (Section 3.0), and compares the costs for each (Section 4.0).The purpose of this document is to assess the costs associated with waste hypergolic fuel. This document will report the costs associated with the current fuel neutralization process and also examine the costs of an alternative technology, microwave destruction of waste hypergolic fuel. The microwave destruction system is being designed as a mobile unit to treat non-specification hypergolic fuel at CCAFS and KSC.

Kessel, Kurt↗
NASA NTRS2013

Woven TPS Enabling Missions Beyond Heritage Carbon Phenolic

Woven Thermal Protection Systems (WTPS) is a new TPS concept that is funded by NASAs Office of the Chief Technologist (OCT) Game Changing Division. The WTPS project demonstrates the potential for manufacturing many TPS architectures capable of performances demanded by the many potential solar system exploration missions. Currently, missions that encounter heat fluxes in the range of 1500 4000 W/sq cm and pressures greater than 1.5 atm have very limited TPS options - only one proven material, fully dense Carbon Phenolic, is currently available for these missions. However, fully dense carbon phenolic is only mass efficient at heat fluxes greater than 4000 W/sq cm, and current mission designs suffer this mass inefficiency for lack of an alternative mid-density TPS. WTPS not only bridges this TPS gap but also offers a replacement for carbon phenolic, which itself requires a significant and costly redevelopment effort to re-establish its capability for use in the high heat flux missions recently prioritized in the NRC Decadal survey, including probe missions to Venus, Saturn and Neptune. This presentation will introduce some woven TPS architectures considered in this project and summarize some recent arc jet testing to evaluate the performance of fully dense and mid density WTPS. Performance comparisons to heritage carbon phenolic will be drawn where applicable.

Stackpoole, Mairead↗
NASA NTRS2014

Crude Oil Remote Sensing, Characterization and Cleaning with CW and Pulsed Lasers

For detection, identification and characterization of crude oil we combine several optical methods of remote sensing of crude oil films and emulsions (coherent fringe projection illumination (CFP), holographic in-line interferometry (HILI), and laser induced fluorescence). These methods allow the three-dimensional characterization of oil spills, important for practical applications. Combined methods of CFP and HILI are described in the frame of coherent superposition of partial interference patterns. It is shown, that in addition to detection/identification laser illumination in the green-blue region can also degrade oil slicks. Different types of surfaces contaminated by oil spills are tested: oil on the water, oil on the flat solid surfaces and oil on the curved surfaces of pipes. For the detection and monitoring of the laser-induced oil degradation in pipes, coherent fiber bundles were used. Both continuous-wave (CW) and pulsed lasers are tested using pump-probe schemes. This finding suggests that properly structured laser clean-up can be an alternative environmentally-friendly method of decontamination, as compared to the currently used chemical methods that are dangerous to environment.

Kukhtareva, Tatiana↗
NASA NTRS2013

Woven TPS Enabling Missions Beyond Heritage Carbon Phenolic

NASAs Office of the Chief Technologist (OCT) Game Changing Division recently funded an effort to advance a Woven TPS (WTPS) concept. WTPS is a new approach to producing TPS architectures that uses precisely engineered 3D weaving techniques to customize material characteristics needed to meet specific missions requirements for protecting space vehicles from the intense heating generated during atmospheric entry. Using WTPS, sustainable, scalable, mission-optimized TPS solutions can be achieved with relatively low life cycle costs compared with the high costs and long development schedules currently associated with material development and certification. WTPS leverages the mature state-of-the-art weaving technology that has evolved from the textile industry to design TPS materials with tailorable performance. Currently, missions anticipated encountering heat fluxes in the range of 1500 4000 Wcm2 and pressures greater than 1.5 atm are limited to using fully dense Carbon Phenolic. However, fully dense carbon phenolic is only mass efficient at higher heat fluxes g(reater than 4000 Wcm2), and current mission designs suffer this mass inefficiency for lack of an alternative mid-density TPS. WTPS not only bridges this mid-density TPS gap but also offers a replacement for carbon phenolic, which itself requires a significant and costly redevelopment effort to re-establish its capability for use in the high heat flux missions recently prioritized in the NRC Decadal survey, including probe missions to Venus, Saturn and Neptune. This presentation will overview the WTPS concept and present some results from initial testing completed comparing WTPS architectures to heritage carbon phenolic.

Woven Thermal protection materials↗
NASA NTRS2014

SEU System Analysis: Not Just the Sum of All Parts

Single event upset (SEU) analysis of complex systems is challenging. Currently, system SEU analysis is performed by component level partitioning and then either: the most dominant SEU cross-sections (SEUs) are used in system error rate calculations; or the partition SEUs are summed to eventually obtain a system error rate. In many cases, system error rates are overestimated because these methods generally overlook system level derating factors. The problem with overestimating is that it can cause overdesign and consequently negatively affect the following: cost, schedule, functionality, and validation/verification. The scope of this presentation is to discuss the risks involved with our current scheme of SEU analysis for complex systems; and to provide alternative methods for improvement.

Single Event Upset (SEU) Testing↗
NASA NTRS2016

[EC5-Space Suit Assembly Team- Internship]

There were three main projects in this internship. The first pertained to the Bearing Dust Cycle Test, in particular automating the test to allow for easier administration. The second concerned modifying the communication system setup in the Z2 suit, where speakers and mics were adjusted to allow for more space in the helmet. And finally, the last project concerned the tensile strength testing of fabrics deemed as candidates for space suit materials and desired to be sent off for radiation testing. The major duties here are split up between the major projects detailed above. For the Bearing Dust Cycle Test, the first objective was to find a way to automate administration of the test, as the previous version was long and tedious to perform. In order to do this, it was necessary to introduce additional electronics and perform programming to control the automation. Once this was done, it would be necessary to update documents concerning the test setup, procedure, and potential hazards. Finally, I was tasked with running tests using the new system to confirm system performance. For the Z2 communication system modifications, it was necessary to investigate alternative speakers and microphones which may have better performance than those currently used in the suit. Further, new speaker and microphone positions needed to be identified to keep them out of the way of the suit user. Once this was done, appropriate hardware (such as speaker or microphone cases and holders) could be prototyped and fabricated. For the suit material strength testing, the first task was to gather and document various test fabrics to identify the best suit material candidates. Then, it was needed to prepare samples for testing to establish baseline measurements and specify a testing procedure. Once the data was fully collected, additional test samples would be prepared and sent off-site to undergo irradiation before being tested again to observe changes in strength performance. For the Bearing Dust Cycle Test, automation was achieved through use of a servo motor and code written in LabVIEW. With this a small electrical servo controller was constructed and added to the system. For the Z2 communication modifications speaker cases were developed and printed, and new speakers and mics were selected. This allowed us to move the speakers and mics to locations to remain out of the suit users way. For the suit material strength testing, five material candidates were identified and test samples were created. These samples underwent testing, and baseline test results were gathered, though these results are currently being investigated for accuracy. The main process efficiency developed during the course of this internship comes from automation of the Bearing Dust Cycle Test. In particular, many hours of human involvement and precise operation are replaced with a simple motor setup. Thus it is no longer required to man the test, saving valuable employee time. This internship has confirmed a few things for me, namely that I both want to work as an engineer for an aerospace firm and that in particular I want to work for the Johnson Space Center. I am also confirmed in my desire to work with electronics, though I was surprised to enjoy prototyping 3D CAD design as much as I did. Therefore, I will make an effort to build my skills in this area so that I can continue to design mechanical models. In fact, I found the process of hands-on prototyping to be perhaps the most fun aspect of my time working here. This internship has also furthered my excitement for continual education, and I will hopefully be pursuing a masters in my field in the near future.

Maicke, Andrew↗
NASA NTRS2013

Woven TPS Enabling Missions Beyond Heritage Carbon Phenolic

WTPS is a new approach to producing TPS architectures that uses precisely engineered 3D weaving techniques to customize material characteristics needed to meet specific missions requirements for protecting space vehicles from the intense heating generated during atmospheric entry. Using WTPS, sustainable, scalable, mission-optimized TPS solutions can be achieved with relatively low life cycle costs compared with the high costs and long development schedules currently associated with material development and certification. WTPS leverages the mature state-of-the-art weaving technology that has evolved from the textile industry to design TPS materials with tailorable performance. Currently, missions anticipated encountering heat fluxes in the range of 1500 4000 Wcm2 and pressures greater than 1.5 atm are limited to using fully dense Carbon Phenolic. However, fully dense carbon phenolic is only mass efficient at higher heat fluxes greater than 4000 Wcm2), and current mission designs suffer this mass inefficiency for lack of an alternative mid-density TPS. WTPS not only bridges this mid-density TPS gap but also offers a replacement for carbon phenolic, which itself requires a significant and costly redevelopment effort to re-establish its capability for use in the high heat flux missions recently prioritized in the NRC Decadal survey, including probe missions to Venus, Saturn and Neptune. This presentation will overview the WTPS concept and present some results from initial testing completed comparing WTPS architectures to heritage carbon phenolic.

ablators↗
NASA NTRS2019

Exploration of Near-Term Potential Routes and Procedures for Urban Air Mobility

This paper investigates routes and procedures for Urban Air Mobility (UAM), which aims to reduce congestion on the roads and highways by offering air taxi as an alternative to driving. The routes and procedures being explored are current-day helicopter routes along with different communication procedures that are available as tools in the near-term. Three different levels of UAM traffic were evaluated in the Dallas Fort Worth (DFW) area. The current-day helicopter routes were modified to separate them from traditional traffic, and a Letter of Agreement (LOA) was introduced in some of the conditions to reduce verbal communications. We found that modifications to the routes and introduction of LOA helped increase the number of UAM flights that the controllers reported they could manage and reduce their communications, which made controller self-reported workload more operationally acceptable. However, the self-reported workload experienced by busy airport towers cannot be effectively managed via the usage of LOA and modified helicopter routes, suggesting there is an opportunity to re-think roles and responsibilities of the UAM system participants.

Verma, Savita A.↗
DOE OSTI2012

APPLICATION FO FLOW FORMING FOR USE IN RADIOACTIVE MATERIAL PACKAGING DESIGNS

This paper reports on the development and testing performed to demonstrate the use of flow forming as an alternate method of manufacturing containment vessels for use in radioactive material shipping packaging designs. Additionally, ASME Boiler and Pressure Vessel Code, Section III, Subsection NB compliance along with the benefits compared to typical welding of containment vessels will be discussed. SRNL has completed fabrication development and the testing on flow formed containment vessels to demonstrate the use of flow forming as an alternate method of manufacturing a welded 6-inch diameter containment vessel currently used in the 9975 and 9977 radioactive material shipping packaging. Material testing and nondestructive evaluation of the flow formed parts demonstrate compliance to the minimum material requirements specified in applicable parts of ASME Boiler and Pressure Vessel Code, Section II. Destructive burst testing shows comparable results to that of a welded design. The benefits of flow forming as compared to typical welding of containment vessels are significant: dimensional control is improved due to no weld distortion; less final machining; weld fit-up issues associated with pipes and pipe caps are eliminated; post-weld non-destructive testing (i.e., radiography and die penetrant tests) is not necessary; and less fabrication steps are required. Results presented in this paper indicate some of the benefits in adapting flow forming to design of future radioactive material shipping packages containment vessels.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2017

Application of a Novel DCPD Adjustment Method for the J-R Curve Characterization: A study based on ORNL and ASTM Interlaboratory Results

Material fracture toughness in the fully ductile region can be described by a J-integral vs. crack growth resistance curve (J-R curve). As a conventional J-R curve measurement method, the elastic unloading compliance (EUC) method becomes impractical for elevated temperature testing due to relaxation of the material and friction induced back-up shape of the J-R curve. One alternative solution of J-R curve testing applies the Direct Current Potential Drop (DCPD) technique for measuring crack extension. However, besides crack growth, potential drop can also be influenced by plastic deformation, crack tip blunting, etc., and uncertainties exist in the current DCPD methodology especially in differentiating potential drop due to stable crack growth and due to material deformation. Thus, using DCPD for J-R curve determination remains a challenging task. In this study, a new adjustment procedure for applying DCPD to derive the J-R curve has been developed for conventional fracture toughness specimens, including compact tension, three-point bend, and disk-shaped compact specimens. Data analysis has been performed on Oak Ridge National Laboratory (ORNL) and American Society for Testing and Materials (ASTM) interlaboratory results covering different specimen thicknesses, test temperatures, and materials, to evaluate the applicability of the new DCPD adjustment procedure for J-R curve characterization. After applying the newly-developed procedure, direct comparison between the DCPD method and the normalization method on the same specimens indicated close agreement for the overall J-R curves, as well as the provisional values of fracture toughness near the onset of ductile crack extension, Jq, and of tearing modulus.

DCPD↗
DOE OSTI2023

Optimizing Geant4 Hadronic Models

Geant4, the leading detector simulation toolkit used in high energy physics, employs a set of physics models to simulate interactions of particles with matter across a wide range of energies. These models, especially the hadronic ones, rely largely on directly measured cross-sections and inclusive characteristics, and use physically motivated parameters. However, they generally aim to cover a broad range of possible simulation tasks and may not always be optimized for a particular process or a given material. The Geant4 collaboration recently made many parameters of the models accessible via a configuration interface. This opens a possibility to fit simulated distributions to the thin target experimental datasets and extract optimal values of the model parameters and the associated uncertainties. Such efforts are currently undertaken by the Geant4 collaboration with the goal of offering alternative sets of model parameters, also known as "tunes", for certain applications. The effort should subsequently lead to more accurate estimates of the systematic errors in physics measurements given the detector simulation role in performing the physics measurements. Results of the study are presented to illustrate how Geant4 model parameters can be optimized through applying fitting techniques, to improve the agreement between the Geant4 and the experimental data.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2018

Building Sustainable and Efficient Markers to Bridge Ten Millennia: The Understanding Issues-18058

Markers of nuclear waste deposits that can be understood through ten millennia have been proposed for preventing from inadvertent human intrusion. It is postulated that currently designed waste repository markers are likely to fail, and an alternative system of markers is proposed based on a praxeological device, i.e., a language-learning by- action device. The key challenge is how should we represent radioactivity in waste repositories in such a way that it is understood by anyone who encounters such markers? Namely, for an adequate interpretation, two issues have to be addressed: to accommodate differing world views, and inevitable changes in languages. What is required is an integrated system that allows us to communicate a complex and abstract concept to all people at all times. That is the goal of our praxeological device, a sign that links a person's actions (praxis) in a particular context to a communication system about those actions and that particular context. That means anyone who experiences such a praxeological device will understand the actions that s/he is about to perform will help her/him to learn the iconic language s/he is reading. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2023

Biofuels Information Center

The purpose of the Biofuels Information Center (BIC) task is to provide relevant data, information, reports, and web-based tools to all bioenergy stakeholders. The BIC task began in FY08 to meet the requirement under Title II, Sec. 229 of the Energy Independence and Security Act of 2007 (EISA) requires DOE to develop a "Biofuels and Biorefinery Information Center". The BIC task supports biofuels pages content on the EERE's most visited website - the Alternative Fuels Data Center (AFDC http://www.afdc.energy.gov) and the Bioenergy Atlas tools (currently archived) (previous address https://maps.nrel.gov). This task results in more than 1.7 million web pageviews (an instance of an internet user visiting a webpage) per year. In FY22, the task completed the final year of the 5 year USDA Biofuels Infrastructure Partnership (BIP). The USDA BIP expanded infrastructure for E15 and/or E85 to approximately 850 stations and NREL received and reviewed data for quality analyzed all infrastructure and sales data collected by USDA. Stations are privately held and previously it was difficult to ascertain infrastructure and sales data. This unique dataset allows insight into infrastructure data (number of pumps and tanks, costs to install new equipment) and sales data (price and volume for E10, E15, E85, and diesel by month). The 2021 USDA BIP National Summary Report is with DOE for review prior to publication. Future work will include the biannual Bioenergy Industry Status Report (4 previous versions have been published) . The task also supports the principal investigator's time to engage stakeholders on infrastructure and deployment of biofuels. This includes leading, membership, and participation in the following roles: member Board of Advisors at the Fuels Institute, voting member for multiple UL standards committees, Co-Chair of the Infrastructure team at Agriculture/Auto/Ethanol, Member of Coordination Research Council's ULSD Corrosion Committee. The Principal investigator routinely responds to industry inquires to assist in deployment of biofuels regularly.

biofuels↗
DOE OSTI2023

Reliable Measures of Spread in High Dimensional Latent Spaces

Understanding geometric properties of the latent spaces of natural language processing models allows the manipulation of these properties for improved performance on downstream tasks. One such property is the amount of data spread in a model’s latent space, or how fully the available latent space is being used. We demonstrate that the commonly used measures of data spread, average cosine similarity and a partition function min/max ratio I (V), do not provide reliable metrics to compare the use of latent space across data distributions. We propose and examine six alternative measures of data spread, all of which improve over these current metrics when applied to seven synthetic data distributions. Of our proposed measures, we recommend one principal component-based measure and one entropy-based measure that provide reliable, relative measures of spread and can be used to compare models of different sizes and dimensionalities.

97 MATHEMATICS AND COMPUTING↗
NASA NTRS1980

Cogeneration Technology Alternatives Study (CTAS). Volume 2: Analytical approach

The use of various advanced energy conversion systems were compared with each other and with current technology systems for their savings in fuel energy, costs, and emissions in individual plants and on a national level. The ground rules established by NASA and assumptions made by the General Electric Company in performing this cogeneration technology alternatives study are presented. The analytical methodology employed is described in detail and is illustrated with numerical examples together with a description of the computer program used in calculating over 7000 energy conversion system-industrial process applications. For Vol. 1, see 80N24797.

Gerlaugh, H. E.↗