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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 649 records · Page 36
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Total OH reactivity measurements in ambient air in a southern Rocky Mountain ponderosa pine forest during BEACHON-SRM08 summer campaign

Total OH reactivity was measured during the Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics and Nitrogen-Southern Rocky Mountain 2008 field campaign (BEACHON-SRM08) held at Manitou Experimental Forest (MEF) in Colorado USA during the summer season in August, 2008. The averaged total OH reactivity was 6.8 s-1, smaller than that measured in urban or suburban areas, while sporadically high OH reactivity was also observed during some evenings. The total OH reactivity measurements were accompanied by observations of traces species such as CO, NO, NOy, O3 and SO2 and VOCs. From the calculation of OH reactivity based on the analysis of these trace species, 35.3-46.3% of OH reactivity for VOCs came from biogenic species that are dominated by 2-methyl-3-butene-2-ol (MBO), and monoterpenes. MBO was the most prominent contribution to OH reactivity of any other trace species. A comparison of observed and calculated OH reactivity shows that the calculated OH reactivity is 29.5-34.8% less than the observed value, implying the existence of missing OH sink. One of the candidates of missing OH was thought to be the oxidation products of biogenic species.

Nakashima, Yoshihiro↗
DOE OSTI2017

Emissions implications of downscaled electricity generation scenarios for the western United States

This study explores how emissions from electricity generation in the Western Interconnection region of the U.S. might respond in circa 2030 to contrasting scenarios for fuel prices and greenhouse gas (GHG) emissions fees. We examine spatial and temporal variations in generation mix across the region and year using the PLEXOS unit commitment and dispatch model with a production cost model database adapted from the Western Electricity Coordinating Council. Emissions estimates are computed by combining the dispatch model results with unit-specific, emissions-load relationships. Wind energy displaces natural gas and coal in scenarios with relatively expensive natural gas or with GHG fees. Correspondingly, annual emissions of NOx, SO2, and CO2 are reduced by 20-40% in these cases. NOx emissions, which are a concern as a precursor of ground-level ozone, are relatively high and consistent across scenarios during summer, when peak electricity loads occur and wind resources in the region are comparatively weak. Accounting for the difference in start-up versus stabilized NOx emissions rates for natural gas plants had little impact on region-wide emissions estimates due to the dominant contribution from coal-fired plants, but would be more important in the vicinity of the natural gas units.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2021

Evaluating the state-of-the-art in remote volcanic eruption characterization Part II: Ulawun volcano, Papua New Guinea

Retrospective eruption characterization is valuable for advancing our understanding of volcanic systems and evaluating our observational capabilities, especially with remote technologies (defined here as a space-borne system or non-local, ground-based instrumentation which include regional and remote infrasound sensors). In June 2019, the open-system Ulawun volcano, Papua New Guinea, produced a VEI 4 eruption. We combined data from satellites (including Sentinel-2, TROPOMI, MODIS, Himawari-8), the International Monitoring System infrasound network, and GLD360 globally detected lightning with information from the local authorities and social media to characterize the pre-, syn- and post-eruptive behaviour. The Rabaul Volcano Observatory recorded ~24 h of seismicity and detected SO 2 emissions ~16 h before the visually-documented start of the Plinian phase on 26 June at 04:20 UTC. Infrasound and SO2 detections suggest the eruption started during the night on 24 June 2019 at 10:39 UTC ~38 h before ash detections with a gas-dominated jetting phase. Local reports and infrasound detections show that the second phase of the eruption started on 25 June 19:28 UTC with ~6 h of jetting. The first detected lightning occurred on 26 June 00:14 UTC, and ash emissions were first detected by Himawari-8 at 01:00 UTC. Post-eruptive satellite imagery indicates new flow deposits to the south and north of the edifice and ash fall to the west and southwest. In particular, regional infrasound data provided novel insight into eruption onset and syn-eruptive changes in intensity. We conclude that, while remote observations are sufficient for detection and tracking of syn-eruptive changes, key challenges in data latency, acquisition, and synthesis must be addressed to improve future near-real-time characterization of eruptions at minimally-monitored or unmonitored volcanoes.

58 GEOSCIENCES↗
DOE OSTI2019

Mechanochemical Nonhydrolytic Sol–Gel-Strategy for the Production of Mesoporous Multimetallic Oxides

Mesoporous metal oxides with wide pore size, high surface area, and uniform porous structures have demonstrated excellent advantages in various fields. Yet, the state-of-art synthesis approaches are dominated by wet chemistry, accompanied by use of excessive solvent, and the requirement of time-consuming drying process. Herein, we report a mechanochemical solid-state route to synthesize mesoporous Al 2 O 3 (meso-Al 2 O 3 ) via aluminum isopropoxide-copolymers assembly. The obtained meso-Al 2 O 3 reflects a record high surface area (~644 m 2 g -1 ) and narrow pore size distribution (centered at ~5 nm). Moreover, a mechanochemical nonhydrolytic sol-gel strategy is introduced to fabricate mesoporous transition metal (Cu, Co, Mn, Fe, Mg, Ni)-aluminum binary oxide by using anhydrous metal chlorides and aluminum isopropoxide interplay. More importantly, four or five metals-aluminum oxide complexes with abundant mesopores and single cubic crystalline phase known as high-entropy ceramics are produced. To the best of our knowledge, mesoporous high-entropy metal oxides have not been prepared before, because the high crystallization temperature would make mesopores collapse. Furthermore, this high-entropy property endows (CuNiFeCoMg)O x -Al 2 O 3 with superior SO2-resisting performance (1000 ppm of SO 2 in N 2 at 280 °C) in the catalytic oxidation of CO compared to single CuO-Al 2 O 3 .

36 MATERIALS SCIENCE↗
DOE OSTI2025

Life-Cycle Emissions and Human Health Implications of Multi-Input, Multi-Output Biorefineries

To meaningfully broaden the supply of fuels for the transportation sector, biofuel production must be scaled up and this requires a wider array of biomass feedstocks, including agricultural residues and organic waste. Rather than pursuing conversion of lignocellulosic biomass to fuels and anaerobic digestion of wastes as separate pathways, there are economic and environmental advantages associated with integrating these processes in a single facility. However, existing research rarely goes beyond carbon footprints in quantifying the effects of such a shift in bioenergy production. In addition to CO2, CH4, and N2O, this study explores the life-cycle air pollution (NH3, volatile organic compounds, NOx, SO2, and PM2.5), marine eutrophication, acidification, and local external cost implications of biorefineries capable of taking in crop residues, food waste, and manure to produce liquid fuel, electricity, and/or other options such as renewable natural gas (RNG), hydrogen, bioplastics, and protein-rich livestock feed. Relative to a single-input, single-output baseline, biorefineries integrated with organic waste codigestion to coproduce electricity or RNG can reduce life-cycle CO2-equivalent emissions by 84-149%, and the monetized external impacts across all scenarios range from $1.07/gallon to -$0.75/gallon ethanol.

Air pollution↗
DOE OSTI2019

Criteria Air Pollutant and Greenhouse Gases Emissions from U.S. Refineries Allocated to Refinery Products

Using Greenhouse Gas Reporting Program data (GHGRP) and National Emissions Inventory data from 2014, we investigate U.S. refinery greenhouse gas (GHG) emissions (CO2, CH4, and N2O) and criteria air pollutant (CAP) emissions (VOC, CO, NOx, SO2, PM10, and PM2.5). The study derives (1) combustion emission factors (EFs) of refinery fuels (e.g., refinery catalyst coke and refinery combined gas), (2) U.S. refinery GHG emissions and CAP emissions per crude throughput at the national and regional levels, and (3) GHG and CAP emissions attributable to U.S. refinery products. The latter two emissions were further itemized by source: combustion emission, process emission, and facility-wide emission. We estimated U.S. refinery product GHG and CAP emissions via energy allocation at the refinery process unit level. The unit energy demand and unit flow information were adopted from the Petroleum Refinery Life Cycle Inventory Model (PRELIM version 1.1) by fitting individual U.S. refineries. This study fills an important information gap because it (1) evaluates refinery CAP emissions along with GHG emissions and (2) provides CAP and GHG emissions not only for refinery main products (gasoline, diesel, jet fuel, etc.) but also for refinery secondary products (asphalt, lubricant, wax, light olefins, etc.).

allocation↗
DOE OSTI2015

Surface Structure Dependence of SO 2 Interaction with Ceria Nanocrystals with Well-defined Surface Facets

The effects of the surface structure of ceria (CeO 2 ) on the nature, strength, and amount of species resulting from SO 2 adsorption were studied using in situ IR and Raman spectroscopies coupled with mass spectrometry, along with first-principles calculations based on density functional theory (DFT). CeO 2 nanocrystals with different morphologies, namely, rods (representing a defective structure), cubes (100 facet), and octahedra (111 facet), were used to represent different CeO 2 surface structures. IR and Raman spectroscopic studies showed that the structure and binding strength of adsorbed species from SO 2 depend on the shape of the CeO 2 nanocrystals. SO 2 adsorbs mainly as surface sulfites and sulfates at room temperature on CeO 2 rods, cubes, and octahedra that were either oxidatively or reductively pretreated. The formation of sulfites is more evident on CeO 2 octahedra, whereas surface sulfates are more prominent on CeO 2 rods and cubes. This is explained by the increasing reducibility of the surface oxygen in the order octahedra < cubes < rods. Bulk sulfites are also formed during SO 2 adsorption on reduced CeO 2 rods. The formation of surface sulfites and sulfates on CeO 2 cubes is in good agreement with our DFT results of SO 2 interactions with the CeO 2 (100) surface. CeO 2 rods desorb SO2 at higher temperatures than cubes and octahedra nanocrystals, but bulk sulfates are formed on CeO 2 rods and cubes after high-temperature desorption whereas only some surface sulfates/sulfites are left on octahedra. This difference is rationalized by the fact that CeO 2 rods have the highest surface basicity and largest amount of defects among the three nanocrystals, so they bind and react with SO 2 strongly and are the most degraded after SO 2 adsorption cycles. The fundamental understanding obtained in this work on the effects of the surface structure and defects on the interaction of SO 2 with CeO 2 provides insights for the design of more sulfur-resistant CeO 2 -based catalysts.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Molecular Simulation of Capture of Sulfur-Containing Gases by Porous Aromatic Frameworks

The adsorption of pure SO2 and H2S and their selective adsorption from various gas mixtures by porous aromatic frameworks (PAFs) are investigated using grand canonical Monte Carlo (GCMC) simulations and first-principles density functional theory calculations. The influence of functional groups including -CH 3 , -CN, -COOH, -COOCH 3 , -OH, -OCH 3 , -NH 2 , and -NO 2 on the adsorption of pure SO 2 and H 2 S as well as selective capture of SO 2 and H 2 S from SO 2 /N 2 , SO 2 /CO 2 , H 2 S/CO 2 , and H 2 S/CH 4 mixtures is explored. Our calculations indicate that PAFs exhibit high loadings for pure SO 2 and H 2 S gas adsorption at 298 K up to 40 bar compare to other gases such as CH 4 and CO 2 . Additional functional groups enhance gas uptake at low pressures because of stronger interaction with the gas molecules while reducing gas uptake at high pressures because of a decrease in pore volume. The contributions of electrostatic interactions to gas adsorption loadings are analyzed in GCMC simulations. Ideal adsorbed solution theory calculations generally overestimate SO 2 and H 2 S adsorption selectivity in gas mixtures but qualitatively predict the trends seen in GCMC simulations for these systems. The GCMC simulations further show that the inclusion of any of the functional groups we considered increases the selectivity of SO 2 /N 2 , SO 2 /CO 2 , H 2 S/CO 2 , and H 2 S/CH 4 relative to unfunctionalized materials. Electron-withdrawing groups such as -CN, -COOH, -COOCH 3 , and -NO 2 are more effective at enhancing adsorption selectivity in this work. Finally, the highest selectivity in the PAFs functionalized by these groups is predicted at the lowest temperature we considered (273 K), whereas it occurs at 298 K for PAFs with other functional groups.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2011

Top-down estimate of anthropogenic emission inventories and their interannual variability in Houston using a mesoscale inverse modeling technique

The 2000 and 2006 Texas Air Quality Study (TexAQS 2000 and 2006) field campaigns took place in eastern Texas in August-October of 2000 and 2006. Several flights of the National Oceanic and Atmospheric Administration (NOAA) and National Center for Atmospheric Research (NCAR) research aircraft were dedicated to characterizing anthropogenic emissions over Houston. Houston is known for having serious problems with non-attainment of air quality standards. We present a method that uses three models and aircraft observations to assess and improve existing emission inventories using an inverse modeling technique. We used 3-dimensional and 4-dimensional variational (3D-VAR and 4D-VAR) inverse modeling techniques based on a least-squares method to improve the spatial and temporal distribution of CO, NOy (sum of all reactive nitrogen compounds), and SO2 emissions predicted by the 4-km-resolution U.S. Environmental Protection Agency (EPA) National Emission Inventory (NEI) for 2005. Differences between the prior and posterior inventories are discussed in detail. We found that in 2006 the prior daytime emissions in the urban area of Houston have to be reduced by 40% {+-} 12% for CO and 7% {+-} 13% for NOy. Over the Houston Ship Channel, where industrial emissions are predominant, the prior emissions have to be reduced by 41% {+-} 15% for CO and 51% {+-} 9% for NOy. Major ports around Houston have their NOy emissions reduced as well, probably due to uncertainties in near-shore ship emissions in the EPA NEI inventory. Using the measurements from the two field campaigns, we assessed the interannual emission variability between 2000 and 2006. Daytime CO emissions from the Houston urban area have been reduced by 8% {+-} 20%, while the NOy emissions have increased by 20% {+-} 12% from 2000 to 2006. In the Houston Ship Channel, the daytime NOy emissions have increased by 13% {+-} 17%. Our results show qualitative consistencies with known changes in Houston emissions sources.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Timescale for Detecting the Climate Response to Stratospheric Aerosol Geoengineering

Stratospheric aerosol geoengineering could be used to maintain global mean temperature despite increased atmospheric greenhouse gas (GHG) concentrations, for example to meet a 1.5C or 2C target. While this might reduce many climate change impacts, the resulting climate would not be the same as one with the same global mean temperature due to lower GHG concentrations. The primary question we consider is how long it would take to detect these differences in a hypothetical deployment. We use a recently available 20-member ensemble of stratospheric sulfate aerosol geoengineering simulations in which SO2 is injected at four different latitudes to maintain not just the global mean temperature, but also the interhemispheric and equator-to-pole gradients. This multiple-latitude strategy better matches the climate changes from increased GHG, while the ensemble allows us both to estimate residual differences even when they are small compared to natural variability, and to estimate the statistics of variability. We first construct a linear emulator to predict the model responses for different scenarios. Under an RCP4.5 scenario in which geoengineering maintains a 1.5C target (providing end-of-century cooling of 1.7C), the change in global mean precipitation is projected to have a signal-to-noise ratio (SNR) greater than one after only 11 years. However, in this scenario, the projected temperature and precipitation changes at a grid-scale are typically small enough that in many regions this threshold is still not reached by the end of this century. These results provide some context for the projected magnitude of climate-changes associated with a limited deployment of stratospheric aerosol cooling.

42 ENGINEERING↗
DOE OSTI2021

Is turning down the sun a good proxy for stratospheric sulfate geoengineering?

Deliberately blocking out a small portion of the incoming solar radiation would cool the climate. One such approach would be injecting SO2 into the stratosphere, which would produce sulfate aerosols that would remain in the atmosphere for 1–3 years, reflecting part of the incoming shortwave radiation. The cooling produced by the aerosols can offset the warming produced by increased greenhouse gas (GHG) concentrations, but it would also affect the climate differently, leading to residual differences compared to a climate not affected by either. Many climate model simulations of geoengineering have used a uniform reduction of the incoming solar radiation as a proxy for stratospheric aerosols, both because many models are not designed to adequately capture relevant stratospheric aerosol processes, and because a solar reduction has often been assumed to capture the most important differences between how stratospheric aerosols and GHG would affect the climate. Here we show that dimming the sun does not produce the same surface climate effects as simulating aerosols in the stratosphere. By more closely matching the spatial pattern of solar reduction to that of the aerosols, some improvements in this idealized representation are possible, with further improvements if the stratospheric heating produced by the aerosols is included. This is relevant both for our understanding of the physical mechanisms driving the changes observed in stratospheric-sulfate geoengineering simulations, and in terms of the relevance of impact assessments that use a uniform solar dimming.

Visioni, Daniele↗
DOE OSTI2014

Carbon nanomaterial produced by microwave exfoliation of graphite oxide: new insights.

We present detailed characterization of graphene-like material obtained through microwave stimulated exfoliation of graphite oxide (GO). Properties of this material were studied by multiple techniques including, among others, X-ray photoelectron spectroscopy, mass-spectroscopy, infrared and Raman spectroscopy, scanning electron microscopy and broadband dielectric spectroscopy. Specific surface area and volume of microwave exfoliated graphite oxide reached 600 m2 g1 and 6 cm3 g1, respectively. It is shown that during such an explosive reduction process the sample emits CO2, CO and H2O and, in some cases, SO2 gases. The resulting reduced material exhibits IR spectra similar to that of graphite and a dc-conductivity of 0.12 S cm1.

Shulga, Y. M.↗
DOE OSTI2018

Improved Thermal Stability of a Copper-containing Ceria-based Catalyst for Low Temperature CO Oxidation under Simulated Diesel Exhaust Conditions

Cerium-zirconium mixed oxides (CZ) containing Cu (CZCu) have very high CO oxidation performance at low temperatures under simulated diesel exhaust conditions; however, CZCu is prone to significant deactivation upon hydrothermal aging. In this work, we discovered that Cu supported on a commercial CZ (GMR6) is thermally stable, and after aging Cu/GMR6 shows comparable activity for CO oxidation to the fresh CZCu. GMR6 is more thermally stable than homemade CZ, and Cu/GMR6 shows a smaller decrease of BET surface area than Cu/CZ upon hydrothermal aging. The decrease of the BET surface area of the catalyst is accelerated by the presence of Cu. The presence of La and Pr in the GMR6 support provides high structural stability and enhanced oxygen mobility. The formation of both surface and bulk carbonates during CO oxidation results in activity decrease of Cu/GMR6. Thermal decomposition of these carbonates fully regenerates Cu/GMR6. The presence of low level of SO2 in the feed gas mixture poisons the CO oxidation activity of Cu/GMR6 forming highly stable sulfates on the CZ support.

CO oxidation, cerium zirconium copper oxide, therm↗
DOE OSTI2018

Molecular Blends of Methylated-Poly(ethylenimine) and Amorphous Porous Organic Cages for SO 2 Adsorption

Porous organic cages (POCs) are emerging porous materials that exhibit intriguing properties in the areas of self-assembly, host-guest interaction, and solution processability. Here in this work, we explore the applicability of POCs as molecular porous supports for polymeric amines. We find that primary amines in poly(ethylenimine) (PEI) can undergo metathesis with the imine bonds present in POCs, resulting in non-porous products. This problem can be overcome by transforming the primary amines in PEI to tertiary amines via methylation. The methylated PEI (mPEI) forms homogeneous composites with amorphous scrambled porous organic cages (ASPOCs) without undesired reactions or phase separation. The microscopic structure of the composites is studied using molecular dynamics simulations. Finally, these composite materials are evaluated as adsorbents for low concentration SO2 (200 ppm) adsorption and show good thermal and cyclic stability.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Seismic energy data analysis of Merapi volcano to test the eruption time prediction using materials failure forecast method (FFM)

The test of eruption time prediction is an effort to prepare volcanic disaster mitigation, especially in the volcano’s inhabited slope area, such as Merapi Volcano. The test can be conducted by observing the increase of volcanic activity, such as seismicity degree, deformation and SO2 gas emission. One of methods that can be used to predict the time of eruption is Materials Failure Forecast Method (FFM). Materials Failure Forecast Method (FFM) is a predictive method to determine the time of volcanic eruption which was introduced by Voight (1988). This method requires an increase in the rate of change, or acceleration of the observed volcanic activity parameters. The parameter used in this study is the seismic energy value of Merapi Volcano from 1990 – 2012. The data was plotted in form of graphs of seismic energy rate inverse versus time with FFM graphical technique approach uses simple linear regression. The data quality control used to increase the time precision employs the data correlation coefficient value of the seismic energy rate inverse versus time. From the results of graph analysis, the precision of prediction time toward the real time of eruption vary between −2.86 up to 5.49 days.

42 ENGINEERING↗
DOE OSTI2015

Atlantic hurricane surge response to geoengineering

Devastating Atlantic hurricanes are relatively rare events. However their intensity and frequency in a warming world may rapidly increase by a factor of 2-7 for each degree of increase in mean global temperature. Geoengineering by stratospheric sulphate aerosol injection cools the tropics relative to the polar regions, including the hurricane main development region in the Atlantic, suggesting that geoengineering may be an effective method of controlling hurricanes. We examine this hypothesis using 8 Earth System Model simulations of climate under the GeoMIP G3 and G4 schemes that use stratospheric aerosols to reduce the radiative forcing under the RCP4.5 scenario. Global mean temperature increases are greatly ameliorated by geoengineering, and tropical temperature increases are at most half of those in RCP4.5, but sulphate injection would have to double between 2020 and 2070 to balance RCP 4.5 to nearly 10 Tg SO2 yr-1, with consequent implications for damage to stratospheric ozone. We project changes in storm frequencies using a temperature-dependent Generalized Extreme Value statistical model calibrated by historical storm surges from 1923 and observed temperatures. The numbers of storm surge events as big as the one that caused the 2005 Katrina hurricane are reduced by about 50% compared with no geoengineering, but this is only marginally statistically significant. Furthermore, when sea level rise differences at 2070 between RCP4.5 and geoengineering are factored in to coastal flood risk, we find that expected flood levels are reduced by about 40 cm for 5 year events and perhaps halved for 50 year surges.

58 GEOSCIENCES↗