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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 1,549 records · Page 86
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Contributions of the low-latitude boundary layer to the finite width magnetotail convection model

The finite tail width model of magnetotail plasma sheet convection has been extended in order to characterize the steady-state convection process. The model assumes uniform plasma sources and accounts for both the duskward gradient/curvature drift and the earthward E x B drift of ions in a 2D magnetic geometry. A secondary source of plasma originating in the dawnside low-latitude boundary layer (LLBL) is added. Model results show that the LLBL may be a significant source of near-tail central plasma sheet plasma during periods of weak convection; a cross-tail pressure gradient from dawn to dusk is predicted in the near magnetotail.

Spence, Harlan E.↗
NASA NTRS1993

Land surface temperature measurements from EOS MODIS data

The task objectives of this reporting phase included: (1) completing the draft of the LST Algorithms Theoretical Basic Document by July 30, 1993; (2) making a detailed characterization of the thermal infrared measurement system including spectrometer, blackbody, and radiation sources; (3) making TIR spectral measurements of water and snow-cover surfaces with the MIDAC M2401 spectrometer; and (4) making conceptual and engineering design of an accessory system for spectrometric measurements at variable angles. These objectives are based on the requirements by the MODIS Science Team and the unique challenge in the development of MODIS LST algorithms: to acquire accurate spectral emissivity data of land covers in the near-term and to make ground validations of the LST product in the long-term with a TIR measurement system.

Wan, Zhengming↗
NASA NTRS1999

TAL Performance and Mission Analysis in a CDL Capacitor Powered Direct-Drive Configuration

The goals of this research are (1) to prove the concept feasibility of a direct-drive electric propulsion system, and (2) to evaluate the performance and characteristics of a Russian TAL (Thruster with Anode Layer) operating in a long-pulse mode, powered by a capacitor-based power source developed at Space Power Institute. The TAL, designated D-55, is characterized by an external acceleration zone and is powered by a unique chemical double layer (CDL) capacitor bank with a capacitance of 4 F at a charge voltage of 400 V. Performance testing of this power supply on the TAL was conducted at NASA Lewis Research Center in Cleveland, OH. Direct thrust measurements of the TAL were obtained at CDL power levels ranging from 450 to 1750 W. The specific impulse encompassed a range from 1150 s to 2200 s, yielding thruster system efficiencies between 50 and 60%. Preliminary mission analysis of the CDL direct-drive concept and other electric propulsion options was performed for the ORACLE spacecraft in 6am/6pm and 12am/12pm, 300 km sun-synchronous orbits. The direct-drive option was competitive with the other systems by increasing available net mass between 5 and 42% and reducing two-year system wet mass between 18 and 63%. Overall, the electric propulsion power requirements for the satellite solar array were reduced between 57 and 91% depending oil the orbit evaluated The direct-drive, CDL capacitor-based concept in electric propulsion thus promises to be a highly-efficient, viable alternative for satellite operations in specific near-Earth missions.

Hrbud, Ivana↗
NASA NTRS2004

Infrared and Passive Microwave Radiometric Sea Surface Temperatures and Their Relationships to Atmospheric Forcing

The current generation of infrared (IR) and passive microwave (MW) satellite sensors provides highly complementary information for monitoring sea surface temperature (SST). On the one hand, infrared sensors provide high resolution and high accuracy but are obscured by clouds. Microwave sensors on the other hand, provide coverage through non-precipitating clouds but have coarser resolution and generally poorer accuracy. Assuming that the satellite SST measurements do not have spatially variable biases, they can be blended combining the merits of both SST products. These factors have motivated recent work in blending the MW and IR data in an attempt to produce high-accuracy SST products with improved coverage in regions with persistent clouds. The primary sources of retrieval uncertainty are, however, different for the two sensors. The main uncertainty in the MW retrievals lies in the effects of wind-induced surface roughness and foam on emissivity, whereas the IR retrievals are more sensitive to the atmospheric water vapor and aerosol content. Average nighttime differences between the products for the month periods of January 1999 and June 2000 are shown. These maps show complex spatial and temporal differences as indicated by the strong spatially coherent features in the product differences and the changes between seasons. Clearly such differences need to be understood and accounted for if the products are to be combined. The overall goals of this project are threefold: (1) To understand the sources of uncertainty in the IR and MW SST retrievals and to characterize the errors affecting the two types of retrieval as a fiction of atmospheric forcing; (2) To demonstrate how representative the temperature difference between the two satellite products is of Delta T; (3) To apply bias adjustments and to device a comprehensive treatment of the behavior of the temperature difference across the oceanic skin layer to determine the best method for blending thermal infrared and passive microwave measurements of SSTs.

Castro, Sandra L.↗
NASA NTRS1989

The fragmentation of 670A MeV neon-20 as a function of depth in water. I. Experiment

We present the final analysis of an experiment to study the interaction of a beam of 670A MeV neon ions incident on a water column set to different thicknesses. The atomic number Z (and, in some cases, the isotopic mass A) of primary beam particles and of the products of nuclear interactions emerging from the water column close to the central axis of the beam was obtained for nuclei between Be (Z = 4) and Ne (Z = 10) using a time-of-flight telescope to measure the velocity and a set of silicon detectors to measure the energy loss of each particle. The fluence of particles of a given charge was obtained and normalized to the incident beam intensity. Corrections were made for accidental coincidences between multiple particles triggering the TOF telescope and for interactions in the detector. The background due to beam particles interacting in beam line elements upstream of the detector was calculated. Sources of experimental artifacts and background in particle identification experiments designed to characterize heavy ion beams for radiobiological research are summarized, and some of the difficulties inherent in this work are discussed. Complete tables of absolutely normalized fluence spectra as a function of LET are included for reference purposes.

NASA Discipline Radiation Health↗
NASA NTRS2007

Infrared Camera Characterization of Bi-Propellant Reaction Control Engines during Auxiliary Propulsion Systems Tests at NASA's White Sands Test Facility in Las Cruces, New Mexico

This paper describes the application of a FUR Systems A40M infrared (IR) digital camera for thermal monitoring of a Liquid Oxygen (LOX) and Ethanol bi-propellant Reaction Control Engine (RCE) during Auxiliary Propulsion System (APS) testing at the National Aeronautics & Space Administration's (NASA) White Sands Test Facility (WSTF) near Las Cruces, New Mexico. Typically, NASA has relied mostly on the use of ThermoCouples (TC) for this type of thermal monitoring due to the variability of constraints required to accurately map rapidly changing temperatures from ambient to glowing hot chamber material. Obtaining accurate real-time temperatures in the JR spectrum is made even more elusive by the changing emissivity of the chamber material as it begins to glow. The parameters evaluated prior to APS testing included: (1) remote operation of the A40M camera using fiber optic Firewire signal sender and receiver units; (2) operation of the camera inside a Pelco explosion proof enclosure with a germanium window; (3) remote analog signal display for real-time monitoring; (4) remote digital data acquisition of the A40M's sensor information using FUR's ThermaCAM Researcher Pro 2.8 software; and (5) overall reliability of the system. An initial characterization report was prepared after the A40M characterization tests at Marshall Space Flight Center (MSFC) to document controlled heat source comparisons to calibrated TCs. Summary IR digital data recorded from WSTF's APS testing is included within this document along with findings, lessons learned, and recommendations for further usage as a monitoring tool for the development of rocket engines.

Holleman, Elizabeth↗
NASA NTRS2011

The Primordial Inflation Explorer (PIXIE) Mission

The Primordial Inflation Explorer (PIXIE) is an Explorer-class mission to map the absolute intensity and linear polarization of the cosmic microwave background and diffuse astrophysical foregrounds over the full sky from frequencies 30 GHz to 6 THz (I cm to 50 I-tm wavelength). PIXIE uses a polarizing Michelson interferometer with 2.7 K optics to measure the difference spectrum between two orthogonal linear polarizations from two co-aligned beams. Either input can view either the sky or a temperature-controlled absolute reference blackbody calibrator. The multimoded optics and high etendu provide sensitivity comparable to kilo-pixel focal plane arrays, but with greatly expanded frequency coverage while using only 4 detectors total. PIXIE builds on the highly successful COBEIFIRAS design by adding large-area polarization-sensitive detectors whose fully symmetric optics are maintained in thermal equilibrium with the CMB. The highly symmetric nulled design provides redundant rejection of major sources of systematic uncertainty. The principal science goal is the detection and characterization of linear polarization from an inflationary epoch in the early universe, with tensor-to-scalar ratio r much less than 10(exp -3). PIXIE will also return a rich data set constraining physical processes ranging from Big Bang cosmology, reionization, and large-scale structure to the local interstellar medium. Keywords: cosmic microwave background, polarization, FTS, bolometer

Kogut, Alan J.↗
NASA NTRS2016

Development of the Model of Galactic Interstellar Emission for Standard Point-Source Analysis of Fermi Large Area Telescope Data

Most of the celestial gamma rays detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope originate from the interstellar medium when energetic cosmic rays interact with interstellar nucleons and photons. Conventional point-source and extended-source studies rely on the modeling of this diffuse emission for accurate characterization. Here, we describe the development of the Galactic Interstellar Emission Model (GIEM),which is the standard adopted by the LAT Collaboration and is publicly available. This model is based on a linear combination of maps for interstellar gas column density in Galactocentric annuli and for the inverse-Compton emission produced in the Galaxy. In the GIEM, we also include large-scale structures like Loop I and the Fermi bubbles. The measured gas emissivity spectra confirm that the cosmic-ray proton density decreases with Galactocentric distance beyond 5 kpc from the Galactic Center. The measurements also suggest a softening of the proton spectrum with Galactocentric distance. We observe that the Fermi bubbles have boundaries with a shape similar to a catenary at latitudes below 20deg and we observe an enhanced emission toward their base extending in the north and south Galactic directions and located within approximately 4deg of the Galactic Center.

gamma rays: diffuse background – gamma rays: gen↗
NASA NTRS2018

Steps Toward Improved Integration, Search, and Analysis of Heterogeneous Data in the Astrobiology Habitable Environments Database

The Astrobiology Habitable Environments Database (AHED) is a new data system being developed as a long-term, open-access repository for astrobiology data. AHED is intended to store user-contributed results from NASA or externally-funded research in astrobiology, and to encourage sharing and synergy within the astrobiology community. However, the interdisciplinary nature of astrobiology presents some specific challenges to data management, integration, and analysis within AHED. In some disciplines (e.g., genomics), open databases thrive because the contributed products are fairly uniform and standardized (e.g., sequence data). In astrobiology, each investigation produces a unique set of data products; this makes it difficult to search across different datasets to find similar data, or to combine results from separate investigations. With AHED, we are taking steps to ensure there is adequate metadata - both at the dataset and record levels - to facilitate search, integration, and analysis. At the dataset level, we are developing a new metadata standard for describing astrobiology datasets, with detailed information about content, funding source, and scientific relevance, along with a set of topical keywords for characterizing datasets. At the record level, we are encouraging users to provide more structured content and finer-grained metadata. In many user-contributed science data repositories, few restrictions are placed on the uploaded data format, and minimal or no record-level metadata is required; thus users are unburdened when it comes to data preparation. The tradeoff is that deep integration and search across datasets is almost impossible without standardized structures and metadata. Although AHED users are free to upload minimally-described datasets, they will be encouraged to use database authoring tools (supplied by the underlying platform - Open Data Repository's Data Publisher) plus a set of customizable astrobiology-specific templates to help structure their data and provide standardized metadata. In reward for their extra effort, AHED will be able to deliver enhanced search, discovery, and analysis capabilities.

astrobiology↗
NASA NTRS2018

Coordinated Microanalysis of Phosphates in High-Titanium Lunar Basalts

Laboratory studies of lunar apatite [Ca5(PO4)3(F,Cl,OH)] have been important for determining the volatile inventory of the interior and the roles volatiles played during the magmatic evolution of the Moon. It has been suggested that high-Ti mare basalts sample volatiles from a distinct reservoir in the lunar mantle. However, there is still debate surrounding the crystallization and post-crystallization history of apatite in those basalts. This information is required before we can use apatite to characterize the abundance or isotopic composition of volatiles in melts or magmatic source regions. Our goal is to investigate the mineral chemistry, crystal structure, and volatile inventory of phosphates in high-Ti basalts from Apollo 11, which will allow us to determine the crystallization history of apatite in these rocks and identify any potential secondary processes that have changed the volatile composition that apatite acquired from the melt.

Barnes, J. J.↗
NASA NTRSDate not supplied

Charge Deposition/Neutralization and Dust Removal via Plasma Interactions

Electrically charged and chemically reactive lunar dust can cause serious problems to spacecraft, surface equipment, and astronaut health, so understanding its interaction with and transport through the lunar plasma environment is important to dust mitigation efforts. We explore the charging of granular material in the natural environment of the Moon, recreate those conditions in the laboratory under high vacuum, and examine dust transport and charge neutralization for application in future lunar missions. Phenomena such as charge deposition via electron and ion beams, photoionization through ultraviolet light exposure, neutralization of charge through impingement by an ionized compressed gas, and tribocharging during dust liberation from surfaces will be presented. Surface materials of interest such as floating/grounded conductors and orthofabric for spacesuits are the preliminary focus of this effort. An electrometer is used to characterize currents interacting with the surfaces in the case of the electron/ion/UV source exposure, an electrostatic voltmeter is used to measure the potential on the surfaces without inadvertently discharging them, and a charge plate monitor is used to verify the efficiency of discharging the surfaces via ionized gas impingement. After setup of the initial charge conditions on the surfaces, a quick burst of high-pressure gas is used to overcome adhesion forces and initially dislodge the dust from the surfaces, followed by a low flow of gas that is ionized via application of a strong electric field. The gas is released in a high vacuum environment so as the pressure drops from the initial compressed state through to the vacuum state, the mean free path reaches a point where ionization can occur before all the gas disperses into the vacuum. This ionized gas can then neutralize both the dust and the surface to ensure minimal resettling. Several parameters such as gas composition, electrode geometry, high voltage waveform shape/polarity, and pulse timing have been explored and will be presented here.

electrostatics↗
NASA NTRSDate not supplied

New Astrophysical Discovery with Ground and Space-Based Observatories

Astronomy is robust with discovery thanks to a wide range of international observing facilities in space and on the ground. For example, space telescopes such as Webb and Hubble are now detecting the most distant galaxies in the universe, as well as the cosmological effects of dark matter and dark energy. Ground based radio telescope arrays are peering into nurseries of star-formation, finding regions of infant stars and also their circumstellar disks in which planetary systems are forming. Even black holes have now been imaged. This overview talk will highlight recent advances in observational astrophysics, especially the scientifically powerful examples where multiple facilities are used in complement. Examples include the study of solar system bodies, the characterization of exoplanet atmospheres, and detections of electromagnetic radiation associated with cosmic sources of gravitational waves.

Jennifer J Wiseman↗
DOE OSTI2017

Empirical Study of Simulation Fidelity in Geographically Distributed Real-Time Simulations

Interconnection of digital real-time simulators over wide-area communication networks is an innovative approach to extend local simulation capabilities. Furthermore it allows for integration of geographically dispersed (Power) Hardware-in-the-Loop resources, thus providing a flexible framework for creating large-scale and unique experiments. An empirical characterization of simulation fidelity is provided in this paper. We analyze different sources of fidelity degradation in geographically distributed real-time simulation of transmission-distribution case study.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2017

Launching a Research Archive for FUSRAP Site Records - 17057

The US Department of Energy Office of Legacy Management (LM) maintains a broad set of Formerly Utilized Sites Remedial Action Program (FUSRAP) document collections. The LM FUSRAP technical staff regularly needs access to documents contained in these record collections. The majority of the FUSRAP records are maintained in a large paper-based collection in the LM records storage facility. These records cover the period prior to 1997 in which DOE was responsible for the remediation efforts of FUSRAP sites. Other FUSRAP records are maintained as PDF files in LM's record keeping system. LM also maintains FUSRAP information in reference repositories in SharePoint directories and on network drives. The reference collection allows LM to keep abreast of active site remediation by the U.S. Army Corps of Engineers (USACE) since 1997. Searching these FUSRAP collections in its current arrangement can be time-consuming and can result in incomplete searches. In response, LM proactively developed the FUSRAP Document Information System (FDIS) to provide a rapid, single-point search and retrieval system to provide real-time access to reference copies of FUSRAP documents. Each entry in FDIS includes metadata listing the FUSRAP site, document title, date, source collection, and pertinent keywords. More significant entries (e.g., certification documents, site characterization reports, waste manifests) include a PDF scan of the entire document. Each PDF file is processed using an advanced optical character recognition (OCR) tool. The first significant content added to FDIS is 45,000 entries documenting remediation work performed primarily in the early 1990's by Bechtel National, Inc. With the entries in FDIS, technical staff will be able to search the collection by site, category and keyword to quickly locate precise required content. LM records staff are also adding records that document remediation and monitoring work at FUSRAP sites where cleanup activities are considered complete. Documents for completed FUSRAP sites will be processed before documents for sites currently being remediated. In the future, FDIS will be populated with information about FUSRAP sites with ongoing remediation work as they are released to LM stewardship. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2026

From Subsurface to System: Offshore CCS Development for the Northeastern U.S. Atlantic Shelf

This study evaluated offshore carbon sequestration potential and infrastructure design along the mid-north Atlantic outer continental shelf, addressing the limited onshore storage options in the northeastern U.S. The objective was to define viable CCS pathways by integrating geological characterization, reservoir modeling, and system-level engineering for decarbonizing regional industrial sources. The work was conducted under US DOE grant FE0032407 for the Regional Initiatives and builds on a previous prospective resources assessment project by Battelle.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2018

Application of sequential extraction and hydrothermal treatment for characterization and enrichment of rare earth elements from coal fly ash

Rare earth elements (REE) play a critical role in the global economy. The concern about the REE supply challenge has stimulated global interest in recovering REE from alternative non-conventional REE sources such as coal fly ash. In this paper, sequential extraction, physical separations and hydrothermal alkaline treatment were explored for characterization and enrichment of REE from coal fly ash. Seven-step sequential extraction of coal fly ash has demonstrated that 86.1% of total REE were associated with the glassy phase of the fly ash, with the remaining REE mainly distributed in the organic and sulfides phase (8.3%), the exchangeable phase (3.7%), and the carbonates phase (1.5%). A process combining physical separations, namely, particle size separation and magnetic separation, and hydrothermal alkaline treatment was proposed for enrichment of REE from coal fly ash. The optimal hydrothermal alkaline treatment condition was determined. It was demonstrated that NaOH concentration, solid-to-liquid ratio, temperature, and reaction duration had significant influence on ash dissolution in NaOH solution. Grinding could also enhance ash dissolution during subsequent hydrothermal alkaline treatment. Furthermore REE were enriched from coal fly ash from 325 mg/kg to 877 mg/kg via the proposed process under optimal hydrothermal alkaline treatment conditions.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2020

Phenotypic and functional characterization of corneal endothelial cells during in vitro expansion

The advent of cell culture-based methods for the establishment and expansion of human corneal endothelial cells (CEnC) has provided a source of transplantable corneal endothelium, with a significant potential to challenge the one donor-one recipient paradigm. However, concerns over cell identity remain, and a comprehensive characterization of the cultured CEnC across serial passages has not been performed. To this end, we compared two established CEnC culture methods by assessing the transcriptomic changes that occur during in vitro expansion. In confluent monolayers, low mitogenic culture conditions preserved corneal endothelial cell state identity better than culture in high mitogenic conditions. Expansion by continuous passaging induced replicative cell senescence. Transcriptomic analysis of the senescent phenotype identified a cell senescence signature distinct for CEnC. We identified activation of both classic and new cell signaling pathways that may be targeted to prevent senescence, a significant barrier to realizing the potential clinical utility of in vitro expansion.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Turbulence-parameter estimation for current-energy converters using surrogate model optimization

Surrogate models maximize information utility by building predictive models in place of computational or experimentally expensive model runs. Marine hydrokinetic current energy converters require large-domain simulations to estimate array efficiencies and environmental impacts. Meso-scale models typically represent turbines as actuator discs that act as momentum sinks and sources of turbulence and its dissipation. An OpenFOAM model was developed where actuator disc k-ε turbulence was characterized using an approach developed for flows through vegetative canopies. Turbine-wake data from laboratory flume experiments collected at two influent turbulence intensities were used to calibrate parameters in the turbulence-source terms in the k-ε equations. Additionally, parameter influences on longitudinal wake profiles were estimated using Gaussian process regression with subsequent optimization minimizing the objective function within 3.1% of those obtained using the full model representation, but for 74% of the computational cost (far fewer model runs). This framework facilitates more efficient parameterization of the turbulence-source equations using turbine-wake data.

16 TIDAL AND WAVE POWER↗