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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 1,351 records · Page 75
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

Impact wave deposits provide new constraints on the location of the K/T boundary impact

All available evidence is consistent with an impact into oceanic crust terminating the Cretaceous Period. Although much of this evidence is incompatible with an endogenic origin, some investigators still feel that a volcanic origin is possible for the Cretaceous/Tertiary (K/T) boundary clay layers. The commonly cited evidence for a large impact stems from delicate clay layers and their components and the impact site has not yet been found. Impact sites have been suggested all over the globe. The impact is felt to have occurred near North America by: the occurrence of a 2 cm thick ejecta layer only at North American locales, the global variation of shocked quartz grain sizes peaking in North America, the global variation of spinel compositions with most refractory compositions occurring in samples from the Pacific region and possibly uniquely severe plant extinctions in the North American region. The K/T boundary interval was investigated as preserved on the banks of the Brazos River, Texas. The K/T fireball and ejecta layers with associated geochemical anomalies were found interbedded with this sequence which apparently allows a temporal resolution 4 orders of magnitude greater than typical K/T boundary sections. A literature search reveals that such coarse deposits are widely preserved at the K/T boundary. Impact wave deposits have not been found elsewhere on the globe, suggesting the impact occurred between North and South America. The coarse deposits preserved in Deep Sea Drilling Project (DSDP) holes 151-3 suggest the impact occurred nearby. Subsequent tectonism has complicated the picture.

Hildebrand, A. R.↗
NASA NTRS1990

Static Wind-Tunnel and Radio-Controlled Flight Test Investigation of a Remotely Piloted Vehicle Having a Delta Wing Planform

At the request of the United States Marine Corps, an exploratory wind-tunnel and flight test investigation was conducted by the Flight Dynamics Branch at the NASA Langley Research Center to improve the stability, controllability, and general flight characteristics of the Marine Corps Exdrone RPV (Remotely Piloted Vehicle) configuration. Static wind tunnel tests were conducted in the Langley 12 foot Low Speed Wind Tunnel to identify and improve the stability and control characteristics of the vehicle. The wind tunnel test resulted in several configuration modifications which included increased elevator size, increased vertical tail size and tail moment arm, increased rudder size and aileron size, the addition of vertical wing tip fins, and the addition of leading-edge droops on the outboard wing panel to improve stall departure resistance. Flight tests of the modified configuration were conducted at the NASA Plum Tree Test Site to provide a qualitative evaluation of the flight characteristics of the modified configuration.

Yip, Long P.↗
NASA NTRS1992

Comparison of JPL-AIRSAR and DLR E-SAR images from the MAC Europe 1991 campaign over testsite Oberpfaffenhofen: Frequency and polarization dependent backscatter variations from agricultural fields

On July 12, the MAC Europe '91 (Multi-Sensor Airborne Campaign) took place over test site Oberpfaffenhofen. The DLR Institute of Radio-Frequency Technology participated with its C-VV, X-VV, and X-HH Experimental Synthetic Aperture Radar (E-SAR). The high resolution E-SAR images with a pixel size between 1 and 2 m and the polarimetric AIRSAR images were analyzed. Using both sensors in combination is a unique opportunity to evaluate SAR images in a frequency range from P- to X-band and to investigate polarimetric information.

Schmullius, C.↗
NASA NTRS1995

Atmospheric Limitations to Repeat-Track Radar Interferometry

In its recent radar imaging mission, the Shuttle Imaging Radar satellite (SIR-C) devoted three days to repeat-track interferometry. We have analyzed the data from a test site in the Mojave desert of California. Although good topography ( +/- 10 m on 21 m postings) was obtained, most of the error was caused by turbulent water vapor in the lower atmosphere. Spatial structure of 6 km and all smaller sizes was observed. The RMS, one-way time delay was found to be 0.24 cm. Essentially identical results were obtained at two wavelengths, 24 and 5.7 cm.

Goldstein, Richard↗
NASA NTRS2003

Cloud Property Retrieval and 3D Radiative Transfer

Cloud thickness and photon mean-free-path together determine the scale of "radiative smoothing" of cloud fluxes and radiances. This scale is observed as a change in the spatial spectrum of cloud radiances, and also as the "halo size" seen by off beam lidar such as THOR and WAIL. Such of beam lidar returns are now being used to retrieve cloud layer thickness and vertical scattering extinction profile. We illustrate with recent measurements taken at the Oklahoma ARM site, comparing these to the-dependent 3D simulations. These and other measurements sensitive to 3D transfer in clouds, coupled with Monte Carlo and other 3D transfer methods, are providing a better understanding of the dependence of radiation on cloud inhomogeneity, and to suggest new retrieval algorithms appropriate for inhomogeneous clouds. The international "Intercomparison of 3D Radiation Codes" or I3RC, program is coordinating and evaluating the variety of 3D radiative transfer methods now available, and to make them more widely available. Information is on the Web at: http://i3rc.gsfc.nasa.gov/. Input consists of selected cloud fields derived from data sources such as radar, microwave and satellite, and from models involved in the GEWEX Cloud Systems Studies. Output is selected radiative quantities that characterize the large-scale properties of the fields of radiative fluxes and heating. Several example cloud fields will be used to illustrate. I3RC is currently implementing an "open source" 3d code capable of solving the baseline cases. Maintenance of this effort is one of the goals of a new 3DRT Working Group under the International Radiation Commission. It is hoped that the 3DRT WG will include active participation by land and ocean modelers as well, such as 3D vegetation modelers participating in RAMI.

Cahalan, Robert F.↗
NASA NTRS2005

Factors Controlling the Properties of Multi-Phase Arctic Stratocumulus Clouds

The 2004 Multi-Phase Arctic Cloud Experiment (M-PACE) IOP at the ARM NSA site focused on measuring the properties of autumn transition-season arctic stratus and the environmental conditions controlling them, including concentrations of heterogeneous ice nuclei. Our work aims to use a large-eddy simulation (LES) code with embedded size-resolved aerosol and cloud microphysics to identify factors controlling multi-phase arctic stratus. Our preliminary simulations of autumn transition-season clouds observed during the 1994 Beaufort and Arctic Seas Experiment (BASE) indicated that low concentrations of ice nuclei, which were not measured, may have significantly lowered liquid water content and thereby stabilized cloud evolution. However, cloud drop concentrations appeared to be virtually immune to changes in liquid water content, indicating an active Bergeron process with little effect of collection on drop number concentration. We will compare these results with preliminary simulations from October 8-13 during MPACE. The sensitivity of cloud properties to uncertainty in other factors, such as large-scale forcings and aerosol profiles, will also be investigated. Based on the LES simulations with M-PACE data, preliminary results from the NASA GlSS single-column model (SCM) will be used to examine the sensitivity of predicted cloud properties to changing cloud drop number concentrations for multi-phase arctic clouds. Present parametrizations assumed fixed cloud droplet number concentrations and these will be modified using M-PACE data.

Fridlind, Ann↗
NASA NTRS2017

CIRIR Programs: Drilling and Research Opportunities at the Rochechouart Impact Structure

Owing to its size, accessibility and erosional level, the Rochechouart impact structure, dated at ~203 +/- 2 Ma (recalc.), is a unique reser-voir of knowledge within the population of the rare terrestrial analogous to large impacts craters observed on planetary surfaces. The site gives direct access to fundamental mechanisms both in impact-related geology (origin and evolution of planets) and biology (habitability of planets, emergence and evolution of life). For the last decade P. Lambert has been installing Rochechouart as International Natural Laboratory for studying impact processes and collateral effects on planetary surfaces. For this purpose the Center for International Research on Impacts and on Rochechouart (CIRIR) was installed on site in 2016 with twofold objectives and activities. First ones are scientific and dedicated to the scientific community. The second are cultural and educational and are dedi-cated to the public sensu lato. We present here the CIRIR, its scientific programs and the related reseach opportunities.

Lambert, P.↗
DOE OSTI2025

Data from: “Bald Cypress (Taxodium distichum) Knees Are Methane Sources Controlled by Geomorphology, Climate, and Hydrologic Extremes”

This dataset is associated with the manuscript “Bald Cypress (Taxodium distichum) Knees Are Methane Sources Controlled by Geomorphology, Climate, and Hydrologic Extremes”. Bald cypress “knees” (aboveground woody roots) have been shown to contribute to wetland methane (CH4) efflux, with large variation within and between studies. To explain this variation, we investigated spatial (i.e., across knee surface, within sites, between sites) and temporal dynamics of CH4 fluxes from knees. Methane fluxes were collected from September 2022 to August 2024 at three locations in western Kentucky, USA, within the Mississippi Alluvial Valley: a main channel (semi-permanently flooded), side channel (seasonally flooded), and reservoir edge (artificially flooded). Knee CH4 fluxes (“Ross_et_al_Knee_Flux_Data.csv”) were measured from multiple heights on knees (20, 40, and 60 cm) of various sizes (knee straight height ranged from 24 to 93 cm) using a LiCOR LI-7810 CH4/CO2/H2O Trace Gas Analyzer. The dataset also includes environmental variables collected with each knee measurement, including water level adjusted for knee-to-knee elevational differences, subsurface and air temperature, and humidity. Soil CH4 fluxes (“Ross_et_al_Soil_Flux_Data.csv”) were also collected adjacent to knees (starting in April 2023) when water levels didn’t overtop soil collars, using a LiCOR Smart Chamber and calculated in SoilFluxPro software. The soil flux dataset includes associated variables collected by the Smart Chamber. Three separate files (“*_Water_Level.csv”) are included for water level and subsurface temperature data collected at each site using HOBO U20L barometric pressure loggers. Each file type (knee flux, soil flux, water level) has an associated data dictionary (“*_dd.csv”). For specifics on methodology used and calculations, see the associated manuscript. The R script includes code used for figures and analyses reported in the manuscript.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1994

An estimate of the comet Shoemaker-Levy 9 fragment sizes from the debris field

The impacts of Comet Shoemaker-Levy 9 left spots on Jupiter with diameters on the order of tens of thousands of kilometers, which have the appearance of debris fields strewn upon the Jovian cloud tops. In this note we employ a measurement of the optical depth of the debris at the impact site of fragment G to estimate mass in the debris field and lower limits to the G fragment mass of 4 x 10(exp12) - 4 x 10(exp 13) g and diameter of 0.1 - 0.3 km.

Knacke, R. F.↗
DOE OSTI2024

High-Pressure Rate Rules for Ether Alkylperoxy Radical Isomerization

The first isomerization reaction of an alkylperoxy (RO 2 ) radical holds significant importance in low-temperature oxidation, as it governs the branching ratios of the hydroperoxyalkyl (QOOH) radicals, which influence the competition between the chain-propagation and chain-branching reactions. In this study, we systematically calculated high-pressure rate rules for the RO 2 isomerization reaction of monoethers, exploring 5-, 6-, 7-, and 8-membered ring transition states. Primary, secondary, and tertiary carbon sites, where both the abstracting peroxy group and the abstracted hydrogen are located, were considered, with particular emphasis on distinguishing between secondary carbons adjacent (alpha) and nonadjacent to the ether functional group. Using the G4//B3LYP/6-311++G(2df,2pd) level of theory and the transition state theory, we estimated the rate constants and the Arrhenius coefficient for over 120 possible isomerization reactions. We examined the effect of ring size and ring atoms, revealing that 6- and 7-membered ring isomerizations were generally the fastest. The impact of the ether functional group on transition states was investigated by comparing reactions with identical ring size, peroxy, and radical positions, but with the ether functional group positioned either outside (i.e., out) or inside (i.e., in) the transition state ring, leading to differences in the rate constants. When comparing to analogous alkane rate constants, differences of up to an order of magnitude were observed, underscoring the need for caution when assigning rate rules by analogy. We applied our rate constants in the di-iso-butyl ether kinetic model and evaluated their influence on low-temperature chemistry finding that they altered the branching ratios by up to a factor of 9, highlighting the significance of site-specific rate constants for more accurate low-temperature modeling.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Review—Development of Highly Active and Stable Catalyst Supports and Platinum–Free Catalysts for PEM Fuel Cell

Metal-free, metal-containing, and template-assisted metal-containing nitrogen-modified carbon-based catalysts carbon composite supports, and highly active and electrochemically stable hybrid cathode catalysts for oxygen reduction reaction are reviewed in this manuscript. Here, novel procedures are developed for the synthesis of (i) highly catalytically active PGM-free catalyst and stable carbon composite catalyst supports. The carbon composite catalyst supports are engineered with optimized BET surface area and pore size distribution and with a well-defined kinetic and mass transfer region during the reaction and their performance is dicussed in detail in this review. The surface activation results in increasing carbon graphitization and inclusion of non-metallic active sites on the support surface. The USC catalysts exhibit the initial performance of 0.91 V and a maximum power density of 177 mW cm –2 , with well-defined kinetic and mass-transfer regions and ~2.5% H 2 O 2 production. Activated carbon composite support (ACCS) is modified to optimize its kinetic activity and its electrochemical stability shows excellent thermal stability and support stability under simulated start-up/shut-down operating conditions. The stabilities of various supports developed in this study are compared with those of a commercial Pt/C catalyst. The active sites for the ORR identified with electrochemical and physicochemical methods are pyridinic-N and quaternary-N.

25 ENERGY STORAGE↗
DOE OSTI2023

The Observed Inefficiency of Explosions to Produce Large Aftershocks: Båth’s Law for Explosions is 2.5

Underground explosions are observed to produce fewer and smaller aftershocks than similar size earthquakes. The seismic magnitude difference $Δm_x$ between an explosion and its largest aftershock is an expression of Båth’s law for explosions. Based on an analysis of a compilation of aftershock studies from Soviet testing at the Semipalatinsk test site in Kazakhstan and observations from American testing at the Nevada National Security Site (NNSS), here we find that the average magnitude difference for explosions $\overline{Δm_x}$ is about 2.5. Based on the NNSS data, two standard deviations of $Δm_x$ is about 1.5. In all the cases studied, from ton to megaton yield, from shallow to overburied depth, and chemical or nuclear source, no explosion aftershock has been larger than the explosion that preceded it. In fact, the two events at the NNSS with the largest aftershock magnitudes relative to the explosion are associated with the collapse of the cavity created by the explosion. This is similar to observations from North Korean testing at the Punggye-ri Test Site, where the largest seismic event following the test is attributed to the collapse after the 2017 explosion and is from 0.8 to 2 magnitude units less than the mainshock.

58 GEOSCIENCES↗
DOE OSTI2023

Particle Flux Measurements during TRACER (TRACER PFM) (Field Campaign Report)

The purpose of this campaign was to deploy an instrument payload collocated with a suite of in situ and remote-sensing aerosol instruments at the urban site at the La Porte, Texas Municipal Airport during the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Tracking Aerosol Convection Interactions Experiment (TRACER) in Houston, Texas. The payload was designed to characterize the physicochemical properties, mixing state, and size-resolved vertical fluxes of aerosols. Deployed aerosol instruments associated with the flux measurements included three condensation particle counters (CPCs) with different lower cutoff diameters ( D > 2.5 nm, D > 10 nm, and D > 40 nm), a single-particle soot photometer (SP2) measuring refractory black carbon, and a portable optical particle spectrometer (POPS) measuring the optical size distribution (~180 nm < D < ~5000 nm). A 10-m flux tower hosted a sonic anemometer (SONIC) for vertical velocity measurements. In addition, a humidified tandem differential mobility analyzer (HTDMA) was deployed to measure the growth factors and hygroscopicity parameter of 15-50 nm-sized particles in order to constrain the composition of compounds responsible for modal aerosol growth during new particle formation/growth events. Finally, a radial differential mobility analyzer (RDMA) was deployed to extend the size distribution measurement to 5 nm.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

A Development of Critical Components for the Modular Staged Pressurized Oxy-Combustion Power Plant

DOE's Coal FIRST (Flexible, Innovative, Resilient, Small, Transformative) Initiative was implemented to encourage the development of the coal plant of the future, which will be capable of flexible operation to meet the needs of the grid; using innovative and cutting-edge components that improve efficiency and reduce emissions; providing resilient power to Americans; being small compared to today's conventional utility-scale coal power plants; and transforming how coal power plant technologies are designed and manufactured. The modular Staged, Pressurized Oxy-Combustion (SPOC) process envisioned by and under development at Washington University in St. Louis (WUSTL) has the potential to achieve these goals. The process offers: 1) a modular plant design for improved operational flexibility; 2) fuel-staging combined with pressurized oxy-combustion, which leads to smaller plant size, higher plant efficiency, and lower cost for pollutant and greenhouse gases removal compared with traditional carbon-capture equipped coal power plants; and 3) small modular boilers and pollutant removal units that can be fabricated in shop and assembled on site, further reducing plant capital costs. Under DOE's support (DE-FE0031925), WUSTL is advancing the development of the critical components for the SPOC power plant, including the integrated combustion system and the direct contact cooler (DCC) from TRL 4 to TRL-5, which would allow them to be subsequently incorporated into a pilot plant. These units are the only two components that are not commercially available for a SPOC plant, and hence, their development is a key step toward the commercialization of SPOC. This work presents the objectives, task descriptions, and current progress of the project. So far, the fabrication of a new combustor design and the convective heat transfer boiler has been completed, and the integration of the combustor, boiler, and DCC is underway. Recent results obtained with the newly designed combustor show a stable coal/methane flame while dry-feeding PRB coal under oxy-combustion conditions.

Magalhaes, Duarte↗
DOE OSTI2023

Modular Staged Pressurized Oxy-Combustion (SPOC) Power Plant for Coal and Biomass – Integration of Combustor Boiler and DCC

Critical to the future of power generation is the development of a power plant that will be capable of flexible operation to meet the needs of the modern grid, providing resilient, low-emissions power to a grid that is increasingly seeing a large penetration of intermittent wind and solar. The modular Staged, Pressurized Oxy-Combustion (SPOC) process envisioned by and under development at Washington University in St. Louis (WUSTL) has the potential to achieve these goals. The process offers: 1) a modular plant design for improved operational flexibility; 2) fuel-staging combined with pressurized oxy-combustion, which leads to smaller plant size, higher plant efficiency, and lower cost for pollutant and greenhouse gas removal compared with traditional carbon-capture equipped coal power plants; and 3) small modular boilers and pollutant removal units that can be fabricated in shop and assembled on site, further reducing plant capital costs. Under DOE's support (DE-FE0031925), WUSTL is advancing the development of the critical components for the SPOC power plant, including the integrated combustion system and the direct contact cooler (DCC) from Technology Readiness Level (TRL) 4 to TRL-5, which would allow these technologies to be subsequently incorporated into a pilot plant. This talk will present an overview of the SPOC technology, CFD modeling and validation for burner and boiler development, and recent results to evaluate critical components for system integration needed to advance its TRL.

Magalhaes, Duarte↗
DOE OSTI2024

Modular Staged Pressurized Oxy-Combustion (SPOC) Power Plant for Coal and Biomass – Integration of Combustor Boiler and DCC

Utilities and grid operators worldwide are under significant pressure to incorporate intermittent renewable sources while strategizing on how to maintain the necessary stability and reliability of the grid. The development of a power plant which will be capable of flexible operation to meet the needs of the grid as more intermittent sources like wind and solar energy are incorporated is key to maintain the reliability of the grid. Through the use of innovative and cutting-edge technologies that improve efficiency and reduce carbon emissions, and being small compared to today's conventional utility-scale power plants, the modular Staged, Pressurized Oxy-Combustion (SPOC) process envisioned by and under development at Washington University in St. Louis (WUSTL) has the potential to achieve these goals. Specifically, the process offers: 1) a modular plant design that allows for better operational flexibility; 2) the utilization of fuel-staging and pressurized oxy-combustion, resulting in smaller plant size, improved plant efficiency, and reduced costs for pollutant and CO2 removal compared to traditional power plants with post-combustion capture technology; and 3) the use of small modular boilers and pollutant removal units that can be constructed off-site leading to reduced capital costs for the plant. WUSTL is advancing the development of the critical components for the SPOC power plant, including the integrated combustor-boiler system and the direct contact cooler. To demonstrate the boiler convective section and to obtain critical data for commercial-scale pressurized boiler design, a simulated convective heat transfer boiler test section was designed and integrated with the combustor (radiant section). A direct contact cooler (DCC) was integrated with the combustor-boiler to demonstrate the dynamic operation of the integrated system and the performance of the DCC, including the efficiency for simultaneous removal of NOx and SOx. This talk will present an update on the evaluation of the critical components for system integration, including heat transfer data from the simulated boiler, scrubbing efficiency for the DCC under different operating conditions, and CFD modeling and validation for burner and boiler development.

Magalhaes, Duarte↗
DOE OSTI2023

Development of the Modular Staged Pressurized Oxy-Combustion (SPOC) Power Plant for Coal and Biomass

Critical to the future of power generation is the development of a power plant that will be capable of flexible operation to meet the needs of the modern grid, providing resilient, low-emissions power to a grid that is increasingly seeing a large penetration of intermittent wind and solar. The modular Staged, Pressurized Oxy-Combustion (SPOC) process envisioned by and under development at Washington University in St. Louis (WUSTL) has the potential to achieve these goals. The process offers: 1) a modular plant design for improved operational flexibility; 2) fuel-staging combined with pressurized oxy-combustion, which leads to smaller plant size, higher plant efficiency, and lower cost for pollutant and greenhouse gases removal compared with traditional carbon-capture equipped coal power plants; and 3) small modular boilers and pollutant removal units that can be fabricated in shop and assembled on site, further reducing plant capital costs. Under DOE's support (DE-FE0031925), WUSTL is advancing the development of the critical components for the SPOC power plant, including the integrated combustion system and the direct contact cooler (DCC) from Technology Readiness Level (TRL) 4 to TRL-5, which would allow these technologies to be subsequently incorporated into a pilot plant. This talk will present an overview of the SPOC technology, CFD modeling and validation for burner and boiler development, and recent results to evaluate critical components needed to advance its TRL.

Magalhaes, Duarte↗
NASA NTRS1971

Petrological character of the Luna 16 sample from Mare Fecunditatis.

A total number of 1858 lithic and vitreous fragments from the Luna 16 core-tube sample are classified. The fragments were taken from soil fractions ranging in size from 150 to 425 microns at levels A and G. No important differences are observed between the proportions of particle types in levels A and G, nor between the soils of Luna 16 and those from the Apollo 11 landing site in the nearby Mare Tranquillitatis.

Wood, J. A.↗