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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Technical Basis for the International Export of Handheld Spectroscopy Detectors

The international export of handheld spectroscopy detectors by the National Nuclear Security Administration (NNSA) to partner states will provide state regulatory authorities and nuclear material owners a way to improve accountancy for accidental gains of nuclear material, including the provision of reports to the IAEA, in order to meet their safeguards agreements. International Atomic Energy Agency (IAEA) safeguards agreements for non-nuclear weapons states requires accountancy for all nuclear material. As defined in Article XX of the IAEA statute, nuclear material includes source materials: "uranium containing the mixture of isotopes occurring in nature," and special fissionable material: "plutonium-239; uranium-233; uranium enriched in the isotopes 235 or 233". For IAEA Member States to meet their requirements under comprehensive safeguards agreements (CSA), safeguards are to be applied on "all source or special fissionable material," which "includes all nuclear material subject to IAEA safeguards". Therefore, accidental gains and losses of nuclear material must be reported to the IAEA. An accidental gain occurs when a state unexpectedly adds nuclear material to their inventory by various means such as seizing smuggled material or the discovery of legacy items previously unaccounted for. The material type and quantity must be added to the State's inventory by updating domestic records and then communicated to the IAEA.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2021

Export Administration Regulations (EAR) and Radiation Tolerant Microelectronics

Sandia National Laboratories was asked to provide a technical feasibility assessment on whether programmability is a viable means to address the radiation levels in the Export Administration Regulations (EAR). Most (if not all) modern Complementary Metal Oxide Semiconductor (CMOS) technologies will exceed at least one of the EAR radiation criteria inherently, there is no longer anything “special” about domestic parts or technologies that exceed EAR radiation criteria. A modern part today is not “designed” to exceed EAR criteria and in fact a part would need to be “specially designed” to fail to meet all of these criteria. And although it is possible to design a part to fail to meet the EAR radiation criteria in an unprogrammed state, such a part would be difficult to design in some technologies, may not achieve the ultimate radiation levels desired, would fail to meet core reliability principles, and may be unsuitable for high consequence applications.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2021

Event-scale predictions of water and nitrogen exports in coastal watersheds

Focal Area(s): The purpose of this white paper is to call for the improvement of the predictability and explainability of the magnitude and timing of water and nutrient exports in coastal watersheds. In this regard, hybrid machine learning approaches and process-based numerical models provide new opportunities to maximize predictability, emulate process-based model components, and explicitly address model uncertainty associated with event-scale predictions in coastal watersheds.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Considerations for Export Control of Accelerators and Accelerator Components

Although nuclear reactors have been the sole source for producing plutonium in all nuclear weapons states, accelerator-driven subcritical reactors are a tantalizing alternative. This report provides a review of accelerator driven technologies and components with a focus on export control.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2024

Quantifying Variability and Controls of Riverine Dissolved Organic Carbon Exported to Arctic Coastal Margins of North America (Final Report)

This project involved implementation and application of a coupled permafrost hydrology and dissolved organic carbon process models to investigate how spatial and seasonal variations in terrestrial hydrology and soil freeze/thaw dynamics influence the mobilization, loading, and export of organic carbon to the stream network for selected arctic basins across northern Alaska and northwest Canada. The model simulations were constrained by detailed observations of in- stream chemistry, soil active layer profile moisture and temperature dynamics, streamflow, soil carbon inventories and satellite microwave remote sensing based assessments of surface soil freeze-thaw dynamics. We developed and applied the numerical modeling and data analysis, incorporating observed data for calibration and validation, in order to investigate the terrestrial hydrology, permafrost dynamics, and associated DOC production and loading to rivers across a region encompassing watersheds draining to the coast. The project produced six publications and three datasets archived in public repositories.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Modeling the Impact of Riparian Hollows on River Corridor Nitrogen Exports

Recent studies in snowmelt-dominated catchments have documented changes in nitrogen (N) retention over time, such as declines in watershed exports of N, though there is a limited understanding of the controlling processes driving these trends. Working in the mountainous headwater East River Colorado watershed, we explored the effects of riparian hollows as N-cycling hotspots and as important small-scale controls on observed watershed trends. Using a modeling-based approach informed by remote sensing and in situ observations, we simulated the N-retention capacity of riparian hollows with seasonal and yearly hydrobiogeochemical perturbations imposed as drivers. We then implemented a scaling approach to quantify the relative contribution of riparian hollows to the total river corridor N budget. We found that riparian hollows primarily serve as N sinks, with N-transformation rates significantly limited by periods of enhanced groundwater upwelling and promoted at the onset of rainfall events. Given these observed hydrologic controls, we expect that the nitrate ( NO 3 - ) sink capacity of riparian hollows will increase in magnitude with future climatic perturbations, specifically the shift to more frequent rainfall events and fewer snowmelt events, as projected for many mountainous headwater catchments. Our current estimates suggest that while riparian hollows provision ~5–20% of NO 3 - to the river network, they functionally act as inhibitors to upland NO 3 - reaching the stream. Our work linking transient hydrological conditions to numerical biogeochemical simulations is an important step in assessing N-retaining features relative to the watershed N budget and better understanding the role of small-scale features within watersheds.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1974

Improved (ERTS) information and its impact on U.S. markets for agricultural commodities: A quantitiative economic investigation of production, distribution and net export effects

An econometric investigation into the markets for agricultural commodities is summarized. An overview of the effort including the objectives, scope, and architecture of the analysis and the estimation strategy employed is presented. The major empirical results and policy conclusions are set forth. These results and conclusions focus on the economic importance of improved crop forecasts, U.S. exports, and government policy operations. A number of promising avenues of further investigation are suggested.

Source record↗
NASA NTRS1986

Satellite detection of phytoplankton export from the mid-Atlantic Bight during the 1979 spring bloom

Analysis of Coastal Zone Color Scanner (CZCS) imagery confirms shipboard and in situ moored fluorometer observations of resuspension of near-bottom chlorophyll within surface waters (1 to 10 m) by northwesterly wind events in the mid-Atlantic Bight. As much as 8 to 16 micrograms chl/l are found during these wind events from March to May, with a seasonal increase of algal biomass until onset of stratification of the water column. Rapid sinking or downwelling apparently occurs after subsequent wind events, however, such that the predominant surface chlorophyll pattern is approx. 0.5 to 1.5 micrograms/l over the continental shelf during most of the spring bloom. Perhaps half of the chlorophyll increase observed by satellite during a wind resuspension event represents in-situ production during the 4 to 5 day interval, with the remainder attributed to accumulation of algal biomass previously produced and temporarily stored within near-bottom water. Present calculations suggest that about 10% of the primary production of the spring bloom may be exported as ungrazed phytoplankton carbon from mid-Atlantic shelf waters to those of the continental slope.

Walsh, J. J.↗
NASA NTRS1990

Design of a Low Cost Short Takeoff-vertical Landing Export Fighter/attack Aircraft

The design of a supersonic short takeoff and vertical landing (STOVL) aircraft is presented that is suitable for export. An advanced four poster, low bypass turbofan engine is to be used for propulsion. Preliminary aerodynamic analysis is presented covering a determination of CD versus CL, CD versus Mach number, as well as best cruise Mach number and altitude. Component locations are presented and center of gravity determined. Cost minimization is achieved through the use of developed subsystems and standard fabrication techniques using nonexotic materials. Conclusions regarding the viability of the STOVL design are presented.

Belcher, Anne↗
NASA NTRS1993

Factors regulating ozone over the United States and its export to the global atmosphere

Attention is given to the factors regulating summertime O3 over the U.S. and its export to the global atmosphere, which are examined via a 3-mo simulation involving a continental-scale 3D photochemical model. It is found that reducing NO(x) emissions by 50 percent from 1985 levels would decrease rural O3 concentrations over the eastern U.S. by about 15 percent under almost all meteorological conditions, while reducing anthropogenic hydrocarbon emissions by 50 percent would have less than a 4 percent effect except in the largest urban plumes. The correlation between O3 concentrations and temperature observed at eastern U.S. sites is attributed in part to the association of high temperatures with regional stagnation, and in part to an actual dependence of O3 production on temperature driven primarily by conversion of NO(x) to PAN.

Jacob, Daniel J.↗
NASA NTRS1921

Comparison of alcogas aviation fuel with export aviation gasoline

Mixtures of gasoline and alcohol when used in internal combustion engines designed for gasoline have been found to possess the advantage of alcohol in withstanding high compression without "knock" while retaining advantages of gasoline with regard to starting characteristics. Test of such fuels for maximum power-producing ability and fuel economy at various rates of consumption are thus of practical importance, with especial reference to high-compression engine development. This report discusses the results of tests which compares the performance of alcogas with x gasoline (export grade) as a standard.

Gage, V R↗
NASA NTRS1995

Heterogeneous concurrent computing with exportable services

Heterogeneous concurrent computing, based on the traditional process-oriented model, is approaching its functionality and performance limits. An alternative paradigm, based on the concept of services, supporting data driven computation, and built on a lightweight process infrastructure, is proposed to enhance the functional capabilities and the operational efficiency of heterogeneous network-based concurrent computing. TPVM is an experimental prototype system supporting exportable services, thread-based computation, and remote memory operations that is built as an extension of and an enhancement to the PVM concurrent computing system. TPVM offers a significantly different computing paradigm for network-based computing, while maintaining a close resemblance to the conventional PVM model in the interest of compatibility and ease of transition Preliminary experiences have demonstrated that the TPVM framework presents a natural yet powerful concurrent programming interface, while being capable of delivering performance improvements of upto thirty percent.

Sunderam, Vaidy↗
NASA NTRS2019

Exposure of the EU-28 Food Imports to Extreme Weather Disasters in Exporting Countries

EU-28 relies on a diversified foreign market, even for crops for which it has a high self-sufficiency.This study contributes to the discussion on the vulnerability of agri-food supply to the impacts of extreme weather disasters (EWD). We focus on the largest import commodities of the EU-28 and we aim to (1) map external dependencies of EU-28 agri-food sector, (2) estimate the impact of EWD on crop production in countries from which the EU-28 receives their imports, and (3) assess the exposure of EU-28 agri-food imports to such impacts. Crop and trade data areacquired through EUROSTAT and FAOSTAT, EWD records from EM-DAT, all between 1961 and 2016. A superposed epoch analysis is used to estimate the impact of EWD on the average national production, yield and harvested area of selected crops in exporting countries. The EU-28 imports between 35-100% of its consumption of soybeans, banana, tropical fruits, coffee and cocoa. Our study reveals a substantial impact of EWD, especially due to droughts andheat waves, on the production of soybeans, tropical fruits, and cocoa, with import weighted impacts of 3, 8, and 7%, respectively. Floods cause weighted impacts of 7% (soybeans) and 8% (tropical fruits). Coffee production shows gains during cold waves, but the inter-annual variability offsets these effects.

Teresa Armada Bras↗
NASA NTRS2021

A Visual Tour of Carbon Export by Sinking Particles

To better quantify the ocean's biological carbon pump, we resolved the diversity of sinking particles that transport carbon into the ocean's interior, their contribution to carbon export, and their attenuation with depth. Sinking particles collected in sediment trap gel layers from four distinct ocean ecosystems were imaged, measured, and classified. The size and identity of particles was used to model their contribution to particulate organic carbon (POC) flux. Measured POC fluxes were reasonably predicted by particle images. Nine particle types were identified, and most of the compositional variability was driven by the relative contribution of aggregates, long cylindrical fecal pellets, and salp fecal pellets. While particle composition varied across locations and seasons, the entire range of compositions was measured at a single well-observed location in the subarctic North Pacific over one month, across 500 m of depth. The magnitude of POC flux was not consistently associated with a dominant particle class, but particle classes did influence flux attenuation. Long fecal pellets attenuated most rapidly with depth whereas certain other classes attenuated little or not at all with depth. Small particles (<100 m) consistently contributed ~5% to total POC flux in samples with higher magnitude fluxes. The relative importance of these small particle classes (spherical mini pellets, short oval fecal pellets, and dense detritus) increased in low flux environments (up to 46% of total POC flux). Imaging approaches that resolve large variations in particle composition across ocean basins, depth, and time will help to better parameterize biological carbon pump models

Carbon flux↗
DOE OSTI2021

Zero-Export Feeder Through Transactive Markets

This presentation summarizes how HELICS was used during a collaborative project with Energy Web Foundation and Exelon Corporation. The primary focus of the research was on designing a transactive energy market to accomplish zero export at the feeder head. The market was tested in a HELICS co-simulation framework and showed significant promise for eliminating back feed at the substation even under high renewable energy penetration levels.

blockchain↗
DOE OSTI2024

Aconitic acid exporter (aexA) increases organic acid production in Aspergillus

Recombinant Aspergillus genetically modified to increase expression of g8846, renamed herein as aconitic acid exporter (aexA), are provided, which in some examples are also genetically inactivated for an endogenous cis-aconitic acid decarboxylase (cadA) gene. Such recombinant Aspergillus produce more aconitic acid as compared to native Aspergillus. Also provided are methods of using such recombinant Aspergillus to increase production of aconitic acid and other organic acids, such as citric acid, itaconic acid, and 3-hydroxypropionic acid (3-HP).

Deng, Shuang↗