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Results for “Nitrous Oxide”

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 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Design of a high density cold gas attitude control system

A comparison of the experimental results of a nitrous oxide cold gas thruster with the predicted performance from a numerical simulation of nozzle operations is discussed. Tests were conducted in a vacuum chamber to verify analytical predictions of both nitrogen and nitrous oxide. Preliminary results indicate an Isp for N2O of 61, and an Isp of 69 for N2. Based on the results of this research, parameters are presented for a nitrous oxide-based reaction control system for a small spacecraft currently under development.

Hall, Sarah E.↗
NASA NTRS1984

The effect of oxygen on denitrification during steady-state growth of Paracoccus halodenitrificans

Steady-state cultures of Paracoccus halodenitrificans were grown anaerobically prior to establishing steady states at different concentrations of oxygen. In the absence of oxygen, nitrate-limited cultures produced dinitrogen, and as the oxygen supply increased, these cultures produced nitrous oxide, then nitrite. These changes reflected two phenomena: the inactivation of nitrous oxide reductase by oxygen and the diversion of electrons from nitrite to oxygen.

Hochstein, L. I.↗
DOE OSTI2021

Rock Fracturing Using High-Pressure Ethylene/Nitrous Oxide Detonations

The present work investigates high initial pressure detonations of a stoichiometric mixture of ethylene and nitrous oxide (C2H4 + 6N2O) as a method of fracturing rock beneath the ground surface. These tests were conducted at a test site operated by the Energetic Materials Research and Testing Center (EMRTC), Socorro, New Mexico. The volume under the surface used for testing (called the Down Hole Assembly) consists of a 0.438 in. ID x 50 ft. long stainless-steel tube running down from the test site to a well bore which is 3 in. ID x 10 ft. long and the rock in the well bore is exposed to the propagating combustion wave. The testing carried out at Zucrow Laboratories in the smaller, alloy steel combustion vessel provided a scaling of pressures expected in the well bore. The combustion is initiated by energizing an EBW (Exploding Bridge Wire) above the ground surface. The experimental setup accommodates one high pressure (100,000 psia) transducer to measure the pressure peak and is placed approximately 5 ft. above the ground surface and 5 ft. downstream of the EBW. The focus of this series of experiments is to investigate the dependence of fracture to the rock beneath the surface on initial pressures of the mixture of ethylene and nitrous oxide. Experiments were carried out at initial pressures varying between 125 psia and 300 psi. The transducer recorded elevated pressures, which were 2.3 to 2.6 times in excess of the CJ values. The experimental results are discussed and explained in this report.

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

What Is the Right Level of Activation of a High-Spin {FeNO} 7 Complex to Enable Direct N–N Coupling? Mechanistic Insight into Flavodiiron NO Reductases

Flavodiiron nitric oxide reductases (FNORs), found in pathogenic bacteria, are capable of reducing nitric oxide (NO) to nitrous oxide (N 2 O) to detoxify NO released by the human immune system. Previously, we reported the first FNOR model system that mediates direct NO reduction (Dong, H. T.; et al. J. Am. Chem. Soc. 2018, 140, 13429-13440), but no intermediate of the reaction could be characterized. Here, we present a new set of model complexes that, depending on the ligand substitution, can either mediate direct NO reduction or stabilize a highly activated high-spin (hs) {FeNO} 7 complex, the first intermediate of the reaction. The precursors, [{Fe II (MPA-(RPhO) 2 )} 2 ] (1, R = H and 2, R = t Bu, Me), were prepared first and fully characterized. Complex 1 (without steric protection) directly reduces NO to N 2 O almost quantitatively, which constitutes only the second example of this reaction in model systems. Contrarily, the reaction of sterically protected 2 with NO forms the stable mononitrosyl complex 3, which shows one of the lowest N-O stretching frequencies (1689 cm -1 ) observed so far for a mononuclear hs-{FeNO} 7 complex. Here this study confirms that an N-O stretch & LE;1700 cm -1 represents the appropriate level of activation of the FeNO unit to enable direct NO reduction. The higher activation level of these hs-{FeNO} 7 complexes required for NO reduction compared to those formed in FNORs emphasizes the importance of hydrogen bonding residues in the active sites of FNORs to activate the bound NO ligands for direct N-N coupling and N2O formation. The implications of these results for FNORs are further discussed.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1974

Absorption cross sections of stratospheric molecules

Two classes of molecular species must be considered in a calculation of photochemical rates in the stratosphere. The first class consists of molecular oxygen and ozone, while the second class contains the remainder of the minor constituents. If accurate values of the transmitted fluxes are required at large optical depths, the cross sections for molecular oxygen and ozone must be known to within a few per cent at least. On the other hand, the photochemical rates for the minor species are given simply by the relevant cross sections. A review of published cross sections is presented, giving attention to molecular oxygen, ozone, nitric oxide, nitrogen dioxide, nitrous oxide, nitric acid, ammonia, water vapor, hydrogen peroxide, carbon monoxide, carbon dioxide, and sulfur dioxide.

Hudson, R. D.↗
NASA NTRS2022

Mineral-Catalysed Formation of Marine NO and N 2 O on the Anoxic Early Earth

Microbial denitrification converts fixed nitrogen species into gases in extant oceans. However, it is unclear how such transformations occurred within the early nitrogen cycle of the Archean. Here 5we present experimental anoxic surface-catalyzed reduction of nitrite and nitrate via green rust and magnetite combined with diffusion and photochemical modeling. We find that in a Fe 2+ -rich marine environment, Fe minerals could have catalyzed abiotic denitrification reactions leading to the formation of nitric oxide (NO) and nitrous oxide (N 2 O). Nitrate did not exhibit reactivity in the presence of either mineral or aqueous Fe2+, however, both minerals induced rapid nitrite reduction 10to NO and N 2 O. While N 2 O escaped into the atmosphere (63% of nitrite-nitrogen, with green rust as catalyst), NO remained associated with precipitates (7%) serving as a potential shuttle to the benthic ocean.The modeling suggests that marine N 2 O emissions would have sustained 0.8-6 ppb of atmospheric N 2 O without a protective ozone layer. Our findings add detail to the as yet incompletely documented Archean nitrogen cycle, implying a globally distributed process driven 15by chemical kinetics similar to those of modern enzymatically mediated conversions.

Steffen Buessecker↗
DOE OSTI2022

Integrated Modeling of U.S. Agricultural Soil Emissions of Reactive Nitrogen and Associated Impacts on Air Pollution, Health, and Climate

Agricultural soils are leading sources of reactive nitrogen (Nr) species including nitrogen oxides (NO x ), ammonia (NH 3 ), and nitrous oxide (N 2 O). Here, the propensity of NO x and NH 3 to generate ozone and fine particulate matter (PM) and associated impacts on health are highly variable, whereas the climate impacts of long-lived N 2 O are independent of emission timing and location. However, these impacts have rarely been compared on a spatially-resolved, monetized basis. In this study, we update the nitrogen scheme in an agroecosystem model to simulate the agricultural emissions of Nr from across the United States. We then apply a reduced-form air pollution health effects model to assess air quality impacts from NO x and NH 3 and a social cost of N 2 O to assess the climate impacts. Assuming an $\$$8.2 million Value of a Statistical Life (VSL) and a $\$$13,100/ton social cost of N 2 O, the air quality impacts are a factor of ~7 to 15 times as large as the climate impacts in heavily populated coastal regions, whereas the ratios are closer to 2.5 in sparsely populated regions. Our results show that air pollution, health, and climate should be considered jointly in future assessments of how farming practices affect Nr emissions.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Microbial Competition for Copper: Impacts on Carbon and Nitrogen Cycling

Activities from this DOE sponsored project focused on two general questions: (1) how does competition between microbes for copper affect emissions of greenhouse gasses, especially methane and nitrous oxide? and (2) how does a novel copper-binding compound (methanobactin) made by some methane-oxidizing bacteria bind and reduce metals, as well as what are the regulatory elements involved in controlling methanobactin synthesis? From these efforts, we have conclusively shown that microbial competition for copper does indeed exert significant control on microbial community composition, as well as affects how microbes produce and consume nitrous oxide. We have also developed much better insights into the basis for methanobactin activity, as well as how methanotrophs control its production.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Gas-phase ion-molecule interactions in a collision reaction cell with triple quadrupole-inductively coupled plasma mass spectrometry: Investigations with N 2 O as the reaction gas

Nitrous oxide (N 2 O) was used as a reaction gas to investigate the gas phase ion-molecule interactions using the Agilent 8900 QQQ-ICP-MS. A multi-element standard containing 45 elements with masses ranging from 9 to 208 u was measured in the presence and absence of N 2 O. The main product ion species observed were oxides and nitrides. Comparison of the N 2 O reaction results with similar measurements conducted with O 2 revealed that N 2 O was more effective at forming oxides in general: the elements Cd and Pb were shown to produce oxides with N 2 O where the reaction did not occur with O 2 . Nitrous oxide was also shown to produce a significant amount of nitride species in a few cases. The general reactivity was shown to be consistent with density functional theory (DFT)-predicted reaction enthalpies, such that all predicted exothermic reactions produced product ions at levels at least 1% of the unreacted ion. Our results show that reaction enthalpy is a reasonable predictor of reactivity with N2O on the timescales of the interactions in non-thermal ICP-MS/MS systems. Our work demonstrates the utility of two relatively new platforms (commercial elemental ICP-MS/MS and EMSL Arrows interface to the NWChem program suite), which allows for the study of a large number of elements within a short period. While DFT with the basis sets utilized here is not the most accurate computational method, it is also not computationally expensive and is shown to be suitable for predicting gas phase reactivity in the QQQ-ICP-MS for the majority of ions studied. Here, the ease and rapidity of data collection and DFT calculations has the potential to be very impactful for the identification of targeted reaction chemistries to be leveraged for analytical method development, such as for the inline separation of isobaric interferences from analytes of interest.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2004

Radicals and Reservoirs in the GMI Chemistry and Transport Model: Comparison to Measurements

The most important use of atmospheric chemistry and transport models is to predict the future composition of the atmosphere. The amounts of gases like chlorofluorcarbons, methyl bromide, nitrous oxide and methane are changing and the stratospheric ozone layer will change because these gases are changing. Methyl bromide, nitrous oxide and methane all have natural sources, and also change because of human activity. Chlorofluorcarbons are man-made gases; these are known to decrease stratospheric ozone and future production is banned. They are long-lived gases, and many decades will pass before they are insignificant in the atmosphere. The models are used to predict changes in ozone and other gases; this is a straightforward application. The models must be also tested using observations for the present day atmosphere. This is a challenging task, because the model contains more than 50 species and more than 150 chemical reactions. Data from satellites, ground stations, aircraft and balloons are used to evaluate the model. Different models that are used in international assessments produce different results; in the most recent assessment some predict that ozone will return to 1980 levels by 2025 and others predict that this will not happen until 2050. Since all the parts of the models are conceptually the same, there must be differences in implementation that produce these differences, This work takes a single model, two different sets of winds and temperatures, and repeats the same prediction for the future. Here we compare the results for these two simulations with many observations. The purpose is to identify differences in the model results for the present atmosphere that will lead to different predictions. This sort of controlled comparison will reduce uncertainty in the predictions for stratospheric ozone.

Douglas, Anne R.↗
NASA NTRS2010

Methane on Mars: Thermodynamic Equilibrium and Photochemical Calculations

The detection of methane (CH4) in the atmosphere of Mars by Mars Express and Earth-based spectroscopy is very surprising, very puzzling, and very intriguing. On Earth, about 90% of atmospheric ozone is produced by living systems. A major question concerning methane on Mars is its origin - biological or geological. Thermodynamic equilibrium calculations indicated that methane cannot be produced by atmospheric chemical/photochemical reactions. Thermodynamic equilibrium calculations for three gases, methane, ammonia (NH3) and nitrous oxide (N2O) in the Earth s atmosphere are summarized in Table 1. The calculations indicate that these three gases should not exist in the Earth s atmosphere. Yet they do, with methane, ammonia and nitrous oxide enhanced 139, 50 and 12 orders of magnitude above their calculated thermodynamic equilibrium concentration due to the impact of life! Thermodynamic equilibrium calculations have been performed for the same three gases in the atmosphere of Mars based on the assumed composition of the Mars atmosphere shown in Table 2. The calculated thermodynamic equilibrium concentrations of the same three gases in the atmosphere of Mars is shown in Table 3. Clearly, based on thermodynamic equilibrium calculations, methane should not be present in the atmosphere of Mars, but it is in concentrations approaching 30 ppbv from three distinct regions on Mars.

Levine, J. S.↗
NASA NTRS1979

Auto Emission Testing

The photos show automobile engines being tested for nitrous oxide emissions, as required by the Environmental Protection Agency (EPA), at the Research and Engineering Division of Ford Motor Company, Dearborn. Michigan. NASA technical information helped the company develop a means of calculating emissions test results. Nitrous oxide emission readings vary with relative humidity in the test facility. EPA uses a standard humidity measurement, but the agency allows manufacturers to test under different humidity conditions, then apply a correction factor to adjust the results to the EPA standard. NASA's Dryden Flight Research Center developed analytic equations which provide a simple, computer-programmable method of correcting for humidity variations. A Ford engineer read a NASA Tech Brief describing the Dryden development and requested more detailed information in the form of a technical support package, which NASA routinely supplies to industry on request. Ford's Emissions Test Laboratory now uses the Dryden equations for humidity-adjusted emissions data reported to EPA.

Source record↗
NASA NTRS1977

International Conference on Problems Related to the Stratosphere

The conference focused on four main areas of investigation: laboratory studies and stratospheric chemistry and constituents, sources for and chemical budget of stratospheric halogen compounds, sources for and chemical budget of stratospheric nitrous oxide, and the dynamics of decision making on regulation of potential pollutants of the stratosphere. Abstracts of the scientific sessions of the conference as well as complete transcriptions of the panel discussions on sources for an atmospheric budget of holocarbons and nitrous oxide are included. The political, social and economic issues involving regulation of potential stratospheric pollutants were examined extensively.

Huntress, W., Jr.↗
NASA NTRS1994

Biomass Burning and the Production of Greenhouse Gases

Biomass burning is a source of greenhouse gases, carbon dioxide, methane, and nitrous oxide. In addition, biomass burning is a source of chemically active gases, including carbon monoxide, nonmethane hydrocarbons, and nitric oxide. These gases, along with methane, lead to the chemical production of tropospheric ozone (another greenhouse gas) as well as control the concentration of the hydroxyl radical, which regulates the lifetime of almost every atmospheric gas. Following biomass burning, biogenic emissions of nitrous oxide, nitric oxide, and methane are significantly enhanced. It is hypothesized that enhanced postburn biogenic emissions of these gases are related to fire-induced changes in soil chemistry and/or microbial ecology. Biomass burning, once believed to be a tropical phenomenon, has been demonstrated by satellite imagery to also be a regular feature of the world's boreal forests. One example of biomass burning is the extensive 1987 fire that destroyed more than 12 million acres of boreal forest in the People's Republic of China and across its border in the Soviet Union. Recent estimates indicate that almost all biomass burning is human-initiated and that it is increasing with time. With the formation of greenhouse and chemically active gases as direct combustion products and a longer-term enhancement of biogenic emissions of gases, biomass burning may be a significant driver for global change.

Levine, Joel S.↗
NASA NTRS2016

Prebiotic Chemistry and Atmospheric Warming of Early Earth by an Active Young Sun

Nitrogen is a critical ingredient of complex biological molecules. Molecular nitrogen, however, which was outgassed Into the Earth's early atmosphere, is relatively chemically inert and nitrogen fixation into more chemically reactive compounds requires high temperatures. Possible mechanisms of nitrogen fixation include lightning, atmospheric shock heating by meteorites, and solar ultraviolet radiation. Here we show that nitrogen fixation in the early terrestrial atmosphere can be explained by frequent and powerful coronal mass ejection events from the young Sun -- so-called superflares. Using magnetohydrodynamic simulations constrained by Kepler Space Telescope observations, we find that successive superflare ejections produce shocks that accelerate energetic particles, which would have compressed the early Earth's magnetosphere. The resulting extended polar cap openings provide pathways for energetic particles to penetrate into the atmosphere and, according to our atmospheric chemistry simulations, initiate reactions converting molecular nitrogen, carbon dioxide and methane to the potent greenhouse gas nitrous oxide as well as hydrogen cyanide, an essential compound for life. Furthermore, the destruction of N2, C02 and CH, suggests that these greenhouse gases cannot explain the stability of liquid water on the early Earth. Instead, we propose that the efficient formation of nitrous oxide could explain a warm early Earth.

Airapetian, V. S.↗
DOE OSTI2020

Microbial functional genes commonly respond to elevated carbon dioxide

Atmospheric CO 2 concentration is increasing, largely due to anthropogenic activities. Previous studies of individual free-air CO 2 enrichment (FACE) experimental sites have shown significant impacts of elevated CO 2 (eCO 2 ) on soil microbial communities; however, no common microbial response patterns have yet emerged, challenging our ability to predict ecosystem functioning and sustainability in the future eCO 2 environment. Here we analyzed 66 soil microbial communities from five FACE sites, and showed common microbial response patterns to eCO 2 , especially for key functional genes involved in carbon and nitrogen fixation (e.g., pcc/acc for carbon fixation, nifH for nitrogen fixation), carbon decomposition (e.g., amyA and pulA for labile carbon decomposition, mnp and lcc for recalcitrant carbon decomposition), and greenhouse gas emissions (e.g., mcrA for methane production, norB for nitrous oxide production) across five FACE sites. Also, the relative abundance of those key genes was generally increased and directionally associated with increased biomass, soil carbon decomposition, and soil moisture. In addition, a further literature survey of more disparate FACE experimental sites indicated increased biomass, soil carbon decay, nitrogen fixation, methane and nitrous oxide emissions, plant and soil carbon and nitrogen under eCO 2 . A conceptual framework was developed to link commonly responsive functional genes with ecosystem processes, such as pcc/acc vs. soil carbon storage, amyA/pulA/mnp/lcc vs. soil carbon decomposition, and nifH vs. nitrogen availability, suggesting that such common responses of microbial functional genes may have the potential to predict ecosystem functioning and sustainability in the future eCO 2 environment.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1981

Stratospheric eddy diffusion coefficients from tracer data

Global distributions of nitrous oxide, methane, ozone, and carbon 14 are used to estimate four sets of stratospheric eddy diffusion coefficients. A photochemical equilibrium model calculates O(3P), O(1D), H, HO2, OH, H2O2, NO, and NO2 densities, as a function of altitude, latitude, and time. The calculated O(1D), OH, and observed Cl densities are used to obtain the eddy profiles associated with the methane and nitrous oxide distributions, for altitudes between 10 and 40 km. Application of a constant flux condition to the seasonally averaged ozone data yields eddy values below 20 km. Time-dependent carbon 14 calculations produce eddy coefficients between 13 and 27 km. A composite profile is obtained by comparing the four sets of coefficients. Further, carbon 14 computations are used to test these profiles as well as those recommended in reports issued by the National Academy of Sciences in 1976 and 1979. The composite eddy profile produces the best agreement.

Massie, S. T.↗
DOE OSTI2023

Oxic–anoxic cycling promotes coupling between complex carbon metabolism and denitrification in woodchip bioreactors

Denitrifying woodchip bioreactors (WBRs) are increasingly used to manage the release of non-point source nitrogen (N) by stimulating microbial denitrification. Woodchips serve as a renewable organic carbon (C) source, yet the recalcitrance of organic C in lignocellulosic biomass causes many WBRs to be C-limited. Prior studies have observed that oxic–anoxic cycling increased the mobilization of organic C, increased nitrate (NO 3 – ) removal rates, and attenuated production of nitrous oxide (N 2 O). Here, in this work, we use multi-omics approaches and amplicon sequencing of fungal 5.8S-ITS2 and prokaryotic 16S rRNA genes to elucidate the microbial drivers for enhanced NO 3 – removal and attenuated N 2 O production under redox-dynamic conditions. Transient oxic periods stimulated the expression of fungal ligninolytic enzymes, increasing the bioavailability of woodchip-derived C and stimulating the expression of denitrification genes. Nitrous oxide reductase (nosZ) genes were primarily clade II, and the ratio of clade II/clade I nosZ transcripts during the oxic–anoxic transition was strongly correlated with the N 2 O yield. Analysis of metagenome-assembled genomes revealed that many of the denitrifying microorganisms also have a genotypic ability to degrade complex polysaccharides like cellulose and hemicellulose, highlighting the adaptation of the WBR microbiome to the ecophysiological niche of the woodchip matrix.

59 BASIC BIOLOGICAL SCIENCES↗