Science.gov

Sample records for methane series part

  1. Methane flux time series for tundra environments

    SciTech Connect

    Whalen, S.C.; Reeburgh, W.E. )

    1988-12-01

    Seasonal measurements of net methane flux were made at permanent sites representing important components of arctic tundra. The sites include Eriophorum tussocks, intertussock depressions, moss-covered areas, and Carex stands. Methane fluxes showed high diel, seasonal, intra site, and between site variability. Eriophorum tussocks and Carex dominated methane release to the atmosphere, with mean annual net methane fluxes of 8.05 + or{minus}2.50 g CH{sub 4}/sq m and 4.88 + or{minus}0.73 g CH{sub 4}/sq m, respectively. Methane fluxes form the moss sites and intertussock depressions were much lower. Over 90% of the mean annual methane flux from the Eriophorum, intertussock depressions, and Carex sites occurred between thaw and freeze-up. Some 40% of the mean annual methane flux from the moss sites occurred during winter. Composite methane fluxes for tussock tundra and Carex-dominated wet meadow tundra environments were produced by weighting measured component fluxes according to areal coverage. Tussock and wet meadow tundra account for an estimated global methane emission of 19-33 Tg/yr. 39 refs., 7 figs., 2 tabs.

  2. MEMO2 MEthane goes MObile - MEasurements and Modelling Part 1

    NASA Astrophysics Data System (ADS)

    Walter, Sylvia; Röckmann, Thomas

    2017-04-01

    MEMO2, a European Training Network with more than 20 collaborators from 7 countries, will identify and evaluate methane emissions and support mitigation measures by I) developing new and advanced mobile methane (CH4) measurements tools and networks, II) isotopic source identification, and III) modelling at different scales. Next to the scientific approach of MEMO2, the training plays an important role in this type of project and the focus lays on educating a new generation of "cross-thinking" scientists, which are able to "out of the box thinking" and effectively implement novel measurement and modelling tools in an interdisciplinary and intersectoral context. Central elements of the training are individual, network-wide, and international training, which should be in balance with the scientific part of the project. This presentation will deal with the challenges of setting up and coordinating a scientific network, which is focussing on the training of researchers in an international consortium.

  3. Aerobic methane oxidation in a coastal environment with seasonal hypoxia - a time series study

    NASA Astrophysics Data System (ADS)

    Steinle, Lea; Bethke, Christina; Schweers, Johanna; Bange, Hermann; Kock, Annette; Lehmann, Moritz F.; Treude, Tina; Niemann, Helge

    2014-05-01

    In the coastal ocean, methane is generally produced in anoxic sediments from where it can migrate through the water column to the atmosphere. A significant amount of methane is consumed along this passage by a series of microbial filter systems. Over the last 15 years, researchers focused on the first filter in marine sediments, the anaerobic oxidation of methane (AOM). Comparably little is known about the second filter, the aerobic methane oxidation (MOx), which is mediated by bacteria and takes place in the oxic water column. MOx is particularly important in shallow coastal environments that account for more than 75 % of the global oceanic methane emissions. Key environmental factors possibly controlling MOx in these systems are subjected to strong temporal variations since coastal regions are highly dynamic systems. We will present results from a time-series study on methane cycling in the water column of a coastal inlet in the southwestern Baltic Sea (Eckernförde Bay, Boknis Eck Time Series Station, 54°31.823 N, 10°02.764 E, 28m water depth; www.bokniseck.de). Results from monthly samplings for the last 8 years revealed year-round methane seepage from the seafloor and methane supersaturation (with respect to the atmospheric equilibrium) of surface waters. Seasonal stratification during the summer months leads to intermittent oxygen depletion (hypoxic to anoxic) in bottom waters in late summer to early fall. The frequency of these low-oxygen events increased over the last 20 years. In addition to oxygen fluctuations, bottom water salinity can vary strongly (17-24 psu) due to regular inflows of salty North Sea water through the Kattegat. Over the course of one and a half years, we investigated MOx rates, the methanotrophic community, methane concentrations and physicochemical parameters of the water column on a quarterly basis. Albeit methane concentrations were high throughout the water column (20-120 nM), methane turnover showed a clear spatial pattern. That

  4. Measuring in situ dissolved methane concentrations in gas hydrate-rich systems, Part 1: Investigating the correlation between tectonics and methane release from sediments

    NASA Astrophysics Data System (ADS)

    Lapham, L.; Wilson, R. M.; Paull, C. K.; Chanton, J.; Riedel, M.

    2010-12-01

    In 2009, an area of extended methane venting at 1200 meters water depth was found with high resolution AUV bathymetry scans on the Northern Cascadia Margin that was previously unknown. When visited by ROV, we found seafloor cracks with active bubble streams and thin bacterial mats suggesting shallow gas and possible pore-fluid saturation. Upon coring into the cracks, a hard-substrate (carbonate or gas hydrate) was punctured and gas flows began. With these observations, we asked the question “is this shallow gas released from the seafloor from regional tectonic activity, and, if so, what is the temporal variability of such release events?” To answer this, we deployed a long term pore-water collection device at one of these gas crack sites, informally named “bubbly gulch”, for 9 months. The device is made up of 4 OsmoSamplers that were each plumbed to a port along a 1-meter probe tip using small diameter tubing. By osmosis, the samplers collected water samples slowly through the ports and maintained them within a 300 meter-long copper tubing coil. Because of the high methane concentrations anticipated, in situ pressures were maintained within the coil by the addition of a high pressure valve. Water samples were collected from the overlying water, at the sediment-water interface, and 6 and 10 cm into the sediments. Bottom water temperatures were also measured over the time series to determine pumping rates of the samplers but also to look for any temporal variability. In May 2010, the samplers were retrieved by ROV during efforts to install seafloor instruments for Neptune Canada. In a land-based lab, the coils were sub-sampled by cutting every 4 meters of tubing. With a pumping rate of 0.5 mL/day, this allowed a temporal resolution of 6 days. To date, one sampler coil has been sub-sampled and measured for methane concentrations and stable carbon isotopes. Preliminary results from this coil show pore-fluids nearly saturated with respect to methane, ~45 m

  5. Ritter reaction in monoterpenes of the p-methane series

    SciTech Connect

    Kozlov, N.G.; Popova, L.A.; Novikova, M.G.

    1986-03-01

    The Ritter reaction was studied for some individual monoterpenes of the p-menthane series (p-menth-1-ene, p-menth-2-ene, p-menth-3-ene, cis- and trans-p-menth-8-ene, dipentene, cis- and trans-p-menthan-8-ol, and ..cap alpha..-terpineol) with acetonitrile in the presence of concentrated sulfuric acid at 20/sup 0/C. The stereochemical structure of the reaction products (substituted amides) was established. Possible paths were proposed for their formation through carbocations in accordance with the previously described transformations of stable carbocations generated from the analogous monoterpenes in superacidic media.

  6. Thermophysical properties of freons: methane series. Part 2

    SciTech Connect

    Altunin, V.V.; Geller, V.Z.; Kremenevskaya, E.A.; Perelshtein, I.I.; Petrov, E.K.

    1987-01-01

    The second volume devoted to this group of halogenated hydrocarbons features thermophysical properties of Freon-10 through Freon-14. Tables offer data on temperatures from the normal boiling point to 473 K, and pressures from 0.1 to 20 MPa. This volume contains a review of equations for the calculation of thermophysical properties of freons; thermophysical properties of Freon-10 (CCl/sub 4/); thermophysical properties of Freon-11 (CFCl/sub 3/); thermophysical properties of Freon-12 (CF/sub 2/Cl/sub 2/); thermophysical properties of Freon-13 (CF/sub 3/Cl); thermophysical properties of Freon-14 (CF/sub 4/).

  7. MEMO2 - MEthane goes MObile - MEasurements and Modelling - Part 2

    NASA Astrophysics Data System (ADS)

    Röckmann, Thomas; Walter, Sylvia

    2017-04-01

    As mitigation of climate change is a key scientific and societal challenge, the 2015 United Nations Climate Change Conference in Paris (COP21) agreed to limit global warming "well below" 2˚ C and, if possible, below 1.5˚ C. Reaching this target requires massive reductions of greenhouse gas emissions, and achieving significant reduction of greenhouse gas emissions is a logical headline targets of the EU climate action and of the H2020 strategy. CH4 emissions are a major contributor to Europe's global warming impact and emissions are not well quantified yet. There are significant discrepancies between official inventories of emissions and estimates derived from direct atmospheric measurement. Effective emission reduction can only be achieved if sources are properly quantified, and mitigation efforts are verified. New advanced combinations of measurement and modelling are needed to archive such quantification. MEMO2 will contribute to the targets of the EU with a focus on methane (CH4). The project will bridge the gap between large-scale scientific estimates from in situ monitoring programs and the 'bottom-up' estimates of emissions from local sources that are used in the national reporting by I) developing new and advanced mobile methane (CH4) measurements tools and networks, II) isotopic source identification, and III) modelling at different scales. Within the project qualified scientists will be educated in the use and implementation of interdisciplinary knowledge and techniques that are essential to meet and verify emission reduction goals. MEMO2 will facilitate intensive collaboration between the largely academic greenhouse gas monitoring community and non-academic partners who are responsible for evaluating and reporting greenhouse gas emissions to policy makers. MEMO2 is a European Training Network with more than 20 collaborators from 7 countries. It is a 4-years project and we will present the project and its objectives to the scientific community to foster

  8. 40 CFR Table W - 7 of Subpart W of Part 98-Default Methane Emission Factors for Natural Gas Distribution

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Methane Emission Factors for Natural Gas Distribution W Table W Protection of Environment ENVIRONMENTAL... Natural Gas Systems Definitions. Pt. 98, Subpt. W, Table W-7 Table W-7 of Subpart W of Part 98—Default Methane Emission Factors for Natural Gas Distribution Natural gas distribution Emission factor...

  9. 40 CFR Table W - 7 of Subpart W of Part 98-Default Methane Emission Factors for Natural Gas Distribution

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Methane Emission Factors for Natural Gas Distribution W Table W Protection of Environment ENVIRONMENTAL... Natural Gas Systems Definitions. Pt. 98, Subpt. W, Table W-7 Table W-7 of Subpart W of Part 98—Default Methane Emission Factors for Natural Gas Distribution Natural gas distribution Emission factor...

  10. Lower Rydberg series of methane: a combined coupled cluster linear response and molecular quantum defect orbital calculation.

    PubMed

    Velasco, A M; Pitarch-Ruiz, J; Sánchez de Merás, Alfredo M J; Sánchez-Marín, J; Martin, I

    2006-03-28

    Vertical excitation energies as well as related absolute photoabsorption oscillator strength data are very scarce in the literature for methane. In this study, we have characterized the three existing series of low-lying Rydberg states of CH4 by computing coupled cluster linear response (CCLR) vertical excitation energies together with oscillator strengths in the molecular-adapted quantum defect orbital formalism from a distorted Cs geometry selected on the basis of outer valence green function calculations. The present work provides a wide range of data of excitation energies and absolute oscillator strengths which correspond to the Rydberg series converging to the three lower ionization potential values of the distorted methane molecule, in energy regions for which experimentally measured data appear to be unavailable.

  11. Trends and Patterns in a New Time Series of Natural and Anthropogenic Methane Emissions, 1980-2000

    NASA Astrophysics Data System (ADS)

    Matthews, E.; Bruhwiler, L.; Themelis, N. J.

    2007-12-01

    We report on a new time series of methane (CH4) emissions from anthropogenic and natural sources developed for a multi-decadal methane modeling study (see following presentation by Bruhwiler et al.). The emission series extends from 1980 through the early 2000s with annual emissions for all countries has several features distinct from the source histories based on IPCC methods typically employed in modeling the global methane cycle. Fossil fuel emissions rely on 7 fuel-process emission combinations and minimize reliance on highly-uncertain emission factors. Emissions from ruminant animals employ regional profiles of bovine populations that account for the influence of variable age- and size-demographics on emissions and are ~15% lower than other estimates. Waste-related emissions are developed using an approach that avoids using of data-poor emission factors and accounts for impacts of recycling and thermal treatment of waste on diverting material from landfills and CH4 capture at landfill facilities. Emissions from irrigated rice use rice-harvest areas under 3 water-management systems and a new historical data set that analyzes multiple sources for trends in water management since 1980. A time series of emissions from natural wetlands was developed by applying a multiple-regression model derived from full process-based model of Walter with analyzed meteorology from the ERA-40 reanalysis.

  12. Time-series measurements of bubble plume variability and water column methane distribution above Southern Hydrate Ridge, Oregon

    NASA Astrophysics Data System (ADS)

    Philip, Brendan T.; Denny, Alden R.; Solomon, Evan A.; Kelley, Deborah S.

    2016-03-01

    An estimated 500-2500 gigatons of methane carbon is sequestered in gas hydrate at continental margins and some of these deposits are associated with overlying methane seeps. To constrain the impact that seeps have on methane concentrations in overlying ocean waters and to characterize the bubble plumes that transport methane vertically into the ocean, water samples and time-series acoustic images were collected above Southern Hydrate Ridge (SHR), a well-studied hydrate-bearing seep site ˜90 km west of Newport, Oregon. These data were coregistered with robotic vehicle observations to determine the origin of the seeps, the plume rise heights above the seafloor, and the temporal variability in bubble emissions. Results show that the locations of seep activity and bubble release remained unchanged over the 3 year time-series investigation, however, the magnitude of gas release was highly variable on hourly time scales. Bubble plumes were detected to depths of 320-620 m below sea level (mbsl), in several cases exceeding the upper limit of hydrate stability by ˜190 m. For the first time, sustained gas release was imaged at the Pinnacle site and in-between the Pinnacle and the Summit area of venting, indicating that the subseafloor transport of fluid and gas is not restricted to the Summit at SHR, requiring a revision of fluid-flow models. Dissolved methane concentrations above background levels from 100 to 300 mbsl are consistent with long-term seep gas transport into the upper water column, which may lead to the build-up of seep-derived carbon in regional subsurface waters and to increases in associated biological activity.

  13. Atmospheric methane time series from Finland and Siberia: source areas and surface flux estimates

    NASA Astrophysics Data System (ADS)

    Kilkki, Juho; Aalto, Tuula; Kouznetsov, Rostislav; Hatakka, Juha; Makelä, Timo; Leskinen, Ari; Laurila, Tuomas

    2016-04-01

    We present atmospheric methane concentrations from a diverse set of Finnish stations and Tiksi, northeastern Siberia, and associate them with source areas and surface fluxes. In Finland, synoptic time scale concentrations are consistent with observations from the WMO/GAW site Pallas, with little difference in mean concentration in well-mixed cases. However, source areas determined with a backward dispersion model show that there is a gradient in sensitivity to both anthropogenic and wetland emissions among the stations. We estimate these flux components in the northern parts of Europe using the available observations. In Tiksi, the concentrations are consistent with nearby micrometeorological measurements and a remote-sensed wetness distribution in the region. Wintertime concentrations are usually close to background concentrations in a global transport model, and overall there are few events attributable to the ocean. In a Bayesian atmospheric inversion with weather-independent emissions, the oceanic source is about a third of wetland emissions in our study area that covers most of northern Yakutia and the East-Siberian Arctic Shelf.

  14. Landfill Methane Recovery. Part 4. Instrumentation. Final report, September 1983-November 1985

    SciTech Connect

    Zimmerman, R.E.; Stetter, J.; Flynn, N.W.

    1985-02-01

    Commercially available analytical detectors capable of monitoring trace levels (1 ppm or less) of halogen- and sulfur-containing hydrocarbons potentially present in a landfill-methane product gas stream were evaluated. The instrumentation data base developed in Landfill Methane Recovery Part 3: Data Analysis and Instrumentation Needs was expanded to include instrument-specific data. Of the more than 350 instrument manufacturers surveyed, 11 were selected for laboratory evaluation of specific instruments. Eight candidate detectors were tested using a set of four standardized gas mixtures and samples of landfill methane. Four of the detectors tested, electron capture, electrolytic, infrared (with Fourier Transform), and photoionization, have the required sensitivity to chlorinated compounds. One, the electrolytic detector, when operated in a total chlorine made, will respond selectively to chlorine. The lead acetate and flame photometric detectors responded well to the sulfur-containing hydrocarbons in the test gases. However, additional development is required for the instrumentation schemes, and detector development will improve the industries options.

  15. Isoreticular Series of (3,24)-Connected Metal-Organic Frameworks: Facile Synthesis and High Methane Uptake Properties

    SciTech Connect

    Barin, G; Krungleviciute, V; Gomez-Gualdron, DA; Sarjeant, AA; Snurr, RQ; Hupp, JT; Yildirim, T; Farha, OK

    2014-03-11

    We have successfully used a highly efficient copper-catalyzed "click" reaction for the synthesis of a new series of hexacarboxylic acid linkers with varying sizes for the construction of isoreticular (3,24)-connected metal-organic frameworks (MOFs)-namely, NU-138, NU-139, and NU-140. One of these MOFs, NU-140, exhibits a gravimetric methane uptake of 0.34 g/g at 65 bar and 298 K, corresponding to almost 70% of the DOE target (0.5 g/g), and has a working capacity (deliverable amount between 65 and 5 bar) of 0.29 g/g, which translates into a volumetric working capacity of 170 cc(STP)/cc. These values demonstrate that NU-140 performs well for methane storage purposes, from both a gravimetric and a volumetric point of view. Adsorption of CO2 and H-2 along with simulated isotherms are also reported.

  16. Landfill Methane Recovery. Part 3. Data analysis and instrumentation needs. Final report, January-September 1983

    SciTech Connect

    Zimmerman, R.E.; Lytwynyshyn, G.; Flynn, N.W.

    1983-12-01

    This study expanded the level of data analysis for the existing volatile organic compound (VOC) data base from Landfill Methane Recovery Part II: Gas Characterization and determined the current instrumentation needs of the landfill methane recovery (LMR) industry. The VOC data analysis was conducted by statistically analyzing the Part II VOC data base using a computer-drive statistical package. The analysis consisted of data base review and corrections, analysis of data distribution within the data base, and analysis of trends and parameter correlation using statistical computations and general linear methods. The instrumentation survey included a survey of the LMR industry to determine current and anticipated trends and applications for LMR instrumentation, a survey of instrumentation manufacturers to determine the type of equipment commercially available, and the development of a computerized data base to match instrumentation needs with equipment availability. Results from this study indicate that these trace contaminants are effectively reduced in gas processed to high-Btu quality and that instrumentation is available for monitoring major and trace components in landfill gas. This instrumentation will enable gas utilities to maintain pipeline-quality gas, whether it is processed landfill gas going into the pipeline or natural gas from conventional sources.

  17. What's the Deal with Methane at LUST Spill Sites? Part 1

    EPA Science Inventory

    This article is specifically intended to discuss methane produced from releases of ethanol and gasoline-ethanol mixtures. There may be other sources of methane at a site, including leaks of natural gas or methane produced from the natural decay of buried plant tissues or from th...

  18. What's the Deal with Methane at LUST Spill Sites? Part 2: Vapor Intrusion

    EPA Science Inventory

    This article is specifically intended to discuss methane produced from releases of ethanol and gasoline-ethanol mixtures. There may be other sources of methane at a site, including leaks of natural gas or methane produced from the natural decay of buried plant tissues or from the...

  19. What's the Deal with Methane at LUST Spill Sites? Part 1

    EPA Science Inventory

    This article is specifically intended to discuss methane produced from releases of ethanol and gasoline-ethanol mixtures. There may be other sources of methane at a site, including leaks of natural gas or methane produced from the natural decay of buried plant tissues or from th...

  20. What's the Deal with Methane at LUST Spill Sites? Part 2: Vapor Intrusion

    EPA Science Inventory

    This article is specifically intended to discuss methane produced from releases of ethanol and gasoline-ethanol mixtures. There may be other sources of methane at a site, including leaks of natural gas or methane produced from the natural decay of buried plant tissues or from the...

  1. 2014 Summer Series - Laura Iraci - Up In the Air: Methane and Ozone Over California

    NASA Image and Video Library

    2014-08-07

    The Alpha Jet Atmospheric eXperiment (AJAX) at NASA Ames Research Center measures in-situ carbon dioxide, methane, and ozone concentrations in the Earth's atmosphere several times each month. The aircraft is stationed at Moffett Field and is outfitted with scientific instruments to measure trace gas concentrations and 3-D wind speeds. This talk will focus on recent observations over dairy operations, fossil fuel infrastructure, and wildfires.

  2. Bio-conversion of water hyacinths into methane gas, part 1

    NASA Technical Reports Server (NTRS)

    Wolverton, B. C.; Mcdonald, R. C.; Gordon, J.

    1974-01-01

    Bio-gas and methane production from the microbial anaerobic decomposition of water hyacinths (Eichhornia crassipes) (Mart) Solms was investigated. These experiments demonstrated the ability of water hyacinths to produce an average of 13.9 ml of methane gas per gram of wet plant weight. This study revealed that sample preparation had no significant effect on bio-gas and/or methane production. Pollution of water hyacinths by two toxic heavy materials, nickel and cadmium, increased the rate of methane production from 51.8 ml/day for non-contaminated plants incubated at 36 C to 81.0 ml/day for Ni-Cd contaminated plants incubated at the same temperature. The methane content of bio-gas evolved from the anaerobic decomposition of Ni-Cd contaminated plants was 91.1 percent as compared to 69.2 percent methane content of bio-gas collected from the fermentation of non-contaminated plants.

  3. A lean methane premixed laminar flame doped with components of diesel fuel part III: Indane and comparison between n-butylbenzene, n-propylcyclohexane and indane

    SciTech Connect

    Pousse, E.; Tian, Z.Y.; Glaude, P.A.; Fournet, R.; Battin-Leclerc, F.

    2010-07-15

    To better understand the chemistry of the combustion of components of diesel fuel, the structure of a laminar lean premixed methane flame doped with indane has been investigated. The inlet gases contained 7.1% (molar) of methane, 36.8% of oxygen and 0.9% of indane corresponding to an equivalence ratio of 0.67 and a ratio C{sub 10}H{sub 14}/CH{sub 4} of 12.8%. The flame has been stabilized on a burner at a pressure of 6.7 kPa (50 Torr) using argon as diluent, with a gas velocity at the burner of 49.1 cm s{sup -1} at 333 K. Quantified species included the usual methane C{sub 0}-C{sub 2} combustion products, but also 16 C{sub 3}-C{sub 5} non-aromatic hydrocarbons, 6 C{sub 1}-C{sub 3} non-aromatic oxygenated compounds, as well as 22 aromatic products, namely benzene, toluene, xylenes, phenylacetylene, ethylbenzene, styrene, propenylbenzene, allylbenzene, n-propylbenzene, methylstyrenes, ethyltoluenes, trimethylbenzenes, n-butylbenzene, dimethylethylbenzene, indene, methylindenes, methylindane, benzocyclobutene, naphthalene, phenol, benzaldehyde, and benzofuran. A new mechanism for the oxidation of indane was proposed whose predictions were in satisfactory agreement with measured species profiles in both flames and jet-stirred reactor experiments. The main reaction pathways of consumption of indane have been derived from flow rate analyses in the two types of reactors. A comparison of the effect of the addition of three components of diesel fuel, namely indane, n-butylbenzene and n-propylcyclohexane (parts I and II of this series of paper), on the structure of a laminar lean premixed methane flame is also presented. (author)

  4. Sinking methane.

    PubMed

    Reay, David S

    2003-02-01

    Concentrations of the powerful greenhouse gas, methane, in our atmosphere have doubled since the beginning of the industrial age. Reducing these levels is a vital part of global efforts to combat global warming. Could we make use of the Earth's own methane sinks?

  5. Writing for professional publication. Part 12: summary of the series.

    PubMed

    Fowler, John

    The previous articles in this series have explored the practical issues of writing for professional publication. In this final article, John Fowler, an experienced nursing lecturer and author, summarises the series and presents an overview of the practicalities of writing for publication.

  6. Accounting Issues: An Essay Series Part VII--Liabilities

    ERIC Educational Resources Information Center

    Laux, Judy

    2008-01-01

    This article, the seventh in the series, presents accounting for liabilities along with some related conceptual and measurement issues. Additional coverage is devoted to potential ethical dilemmas and both theoretical and empirical literature related to this set of accounting elements.

  7. Accounting Issues: An Essay Series Part VIII--Stockholders' Equity

    ERIC Educational Resources Information Center

    Laux, Judy

    2008-01-01

    This eighth installment in the series on accounting theory pertains to stockholders' equity and its related conceptual, measurement and ethical issues. Coverage includes the associated theoretical, empirical, and popular literature. (Contains 5 footnotes.)

  8. Accounting Issues: An Essay Series Part VII--Liabilities

    ERIC Educational Resources Information Center

    Laux, Judy

    2008-01-01

    This article, the seventh in the series, presents accounting for liabilities along with some related conceptual and measurement issues. Additional coverage is devoted to potential ethical dilemmas and both theoretical and empirical literature related to this set of accounting elements.

  9. 40 CFR Table W - 5 of Subpart W of Part 98-Default Methane Emission Factors for Liquefied Natural Gas (LNG) Storage

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Methane Emission Factors for Liquefied Natural Gas (LNG) Storage W Table W Protection of Environment... Petroleum and Natural Gas Systems Definitions. Pt. 98, Subpt. W, Table W-5 Table W-5 of Subpart W of Part 98—Default Methane Emission Factors for Liquefied Natural Gas (LNG) Storage LNG storage Emission factor (scf...

  10. 40 CFR Table W - 5 of Subpart W of Part 98-Default Methane Emission Factors for Liquefied Natural Gas (LNG) Storage

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Methane Emission Factors for Liquefied Natural Gas (LNG) Storage W Table W Protection of Environment... Petroleum and Natural Gas Systems Definitions. Pt. 98, Subpt. W, Table W-5 Table W-5 of Subpart W of Part 98—Default Methane Emission Factors for Liquefied Natural Gas (LNG) Storage LNG storage Emission factor (scf...

  11. Accounting Issues: An Essay Series. Part II--Accounts Receivable

    ERIC Educational Resources Information Center

    Laux, Judith A.

    2007-01-01

    This is the second in a series of articles designed to help academics refocus the introductory accounting course on the theoretical underpinnings of accounting. Intended as a supplement for the principles course, this article connects the asset Accounts Receivable to the essential theoretical constructs, discusses the inherent tradeoffs and…

  12. Accounting Issues: An Essay Series Part III--Inventory

    ERIC Educational Resources Information Center

    Laux, Judy

    2007-01-01

    The third in a series of theoretical essays intended to supplement the introductory financial accounting course, this article is dedicated to the treatment of inventory and its related conceptual connections. In addition, this paper addresses inventory measurement dilemmas, describes scandalous accounting episodes that have made the headlines, and…

  13. Accounting Issues: An Essay Series Part V--Intangible Assets

    ERIC Educational Resources Information Center

    Laux, Judy

    2008-01-01

    This article represents the fifth in a series of theoretical essays intended to supplement the introductory financial accounting course and investigates the accounting treatment and related conceptual connections for intangibles. In addition, intangibles present unique accounting issues, conceptual challenges, and measurement dilemmas not found…

  14. Accounting Issues: An Essay Series Part III--Inventory

    ERIC Educational Resources Information Center

    Laux, Judy

    2007-01-01

    The third in a series of theoretical essays intended to supplement the introductory financial accounting course, this article is dedicated to the treatment of inventory and its related conceptual connections. In addition, this paper addresses inventory measurement dilemmas, describes scandalous accounting episodes that have made the headlines, and…

  15. Campus Ecology, Part 2 of a Series: Pond Water

    ERIC Educational Resources Information Center

    Bryan, R. C.

    1974-01-01

    Presents a series of activities which focus on the study of the physical characteristics of water, including temperatures, opacity, pH-values, oxygen concentrations, reagents, and free CO2 concentrations. Indicates that ponds can provide the students with opportunities to learn chemistry, geology, biology, botany, and the effects of weather. (CC)

  16. Accounting Issues: An Essay Series Part V--Intangible Assets

    ERIC Educational Resources Information Center

    Laux, Judy

    2008-01-01

    This article represents the fifth in a series of theoretical essays intended to supplement the introductory financial accounting course and investigates the accounting treatment and related conceptual connections for intangibles. In addition, intangibles present unique accounting issues, conceptual challenges, and measurement dilemmas not found…

  17. Campus Ecology, Part 2 of a Series: Pond Water

    ERIC Educational Resources Information Center

    Bryan, R. C.

    1974-01-01

    Presents a series of activities which focus on the study of the physical characteristics of water, including temperatures, opacity, pH-values, oxygen concentrations, reagents, and free CO2 concentrations. Indicates that ponds can provide the students with opportunities to learn chemistry, geology, biology, botany, and the effects of weather. (CC)

  18. ISKME Special Series Part 2: Data Use and School Reform

    ERIC Educational Resources Information Center

    Petrides, Lisa A.

    2006-01-01

    This is the second part of a four-part report on data-driven decision-making. Widespread attention to school accountability, driven by state and federal mandates, has increased the stakes for all schools. These mandates have made more data available to educators at all levels, but they have not been as effective in encouraging teachers to use…

  19. Lecture Series. Boundary Layer Theory. Part 1. Laminar Flows

    DTIC Science & Technology

    1949-04-01

    conditions =: p ’ =0 The solution found by series development can be found in the thesis of Hiemenz (reference 10), compare table 1*. The velocity...Boundary Layer on the Cylinder (symmetrical case) The integration method of Blasius given in the previous section was used by Hiemenz (thesis G6ttingen...the differential equations (9.33) are best obtained by numerical integration. The functions f, and f3 were already calculated by Hiemenz (reference

  20. Jackson's Mill Industrial Arts Curriculum Theory: A Base for Curriculum Conceptualization. Part 2 of a Two-Part Series.

    ERIC Educational Resources Information Center

    Hales, James A.; Snyder, James F.

    1982-01-01

    Presents narratives, charts, and diagrams showing the unique aspects of the four subsystems of human technical endeavor. These subsystems are communication, construction, manufacturing, and transportation. (For part 1 of this series, see CE 511 770.) (CT)

  1. Methane to syngas conversion. Part I. Equilibrium conditions and stability requirements of membrane materials

    NASA Astrophysics Data System (ADS)

    Frade, J. R.; Kharton, V. V.; Yaremchenko, A.; Naumovich, E.

    Thermodynamic data have been used to predict the dependence of methane conversion on temperature and oxygen partial pressure in mixed conducting membrane reactors, and the corresponding fractions of water vapor, H 2, CO and CO 2. The relations between methane conversion, gas composition and oxygen partial pressure were also used to formulate the oxygen balance in mixed conducting membrane reactors, with tubular reactor and continuous stirred tank reactor (CSTR) configurations. A single dimensionless parameter accounts for the combined effects of geometric parameters of the membrane reactor, the permeability of the membrane material, and flow rate at the entry of the reactor. Selected examples were calculated to illustrate the effects of steam to methane and inert to methane ratios in the gas entering the reactor. The values of oxygen partial pressure required to attain the highest yield of CO and H 2 were also used to estimate the stability requirements to be met by mixed conducting membrane materials. Suitable membrane designs might be needed to bridge the difference between the conditions inside the reactors and the stability limits of known mixed conductors.

  2. Methane oxidation in a biofilter (Part 1): Development of a mathematical model for designing and optimization.

    PubMed

    Amodeo, Corrado; Masi, Salvatore; Van Hulle, Stijn W H; Zirpoli, Pierfrancesco; Mancini, Ignazio M; Caniani, Donatella

    2015-01-01

    The aim of this work is the evaluation of the efficiency of such a biofilter, through the application of a mathematical model which describes the biological oxidation process. This mathematical model is able to predict the efficiency of the system under varying operating conditions. Literature data have been used in order to build the model. The factors that mostly affect the process and which actually regulate the entire process have been highlighted in this work. Specifically, it was found that temperature, flow and methane concentration are the most important parameters that influence the system. The results obtained from the mathematical model showed also that the biofilter system is simple to implement and manage and allows the achievement of high efficiency of methane oxidation. In the optimal conditions for temperature (between 20-30°C), residence time (between 0.7-0.8 h) and methane molar fraction (between 20-25%) the efficiency of methane oxidation could be around 50%.

  3. BEGINNING CHINESE READER, PART I. YALE LINGUISTIC SERIES.

    ERIC Educational Resources Information Center

    DE FRANCIS, JOHN; AND OTHERS

    THIS READER, ALONG WITH "BEGINNING CHINESE READER, PART II," IS CLOSELY INTEGRATED WITH THE SETON HALL UNIVERSITY TEXTS FOR SPOKEN AND WRITTEN CHINESE, "BEGINNING CHINESE" AND "CHARACTER TEXT FOR BEGINNING CHINESE." OF THE 400 CHARACTERS IN THESE TWO READERS, ALL BUT 33 HAVE BEEN PRESENTED TO THE STUDENT IN "BEGINNING CHINESE" AND "CHARACTER…

  4. BEGINNING CHINESE READER, PART I. YALE LINGUISTIC SERIES.

    ERIC Educational Resources Information Center

    DE FRANCIS, JOHN; AND OTHERS

    THIS READER, ALONG WITH "BEGINNING CHINESE READER, PART II," IS CLOSELY INTEGRATED WITH THE SETON HALL UNIVERSITY TEXTS FOR SPOKEN AND WRITTEN CHINESE, "BEGINNING CHINESE" AND "CHARACTER TEXT FOR BEGINNING CHINESE." OF THE 400 CHARACTERS IN THESE TWO READERS, ALL BUT 33 HAVE BEEN PRESENTED TO THE STUDENT IN "BEGINNING CHINESE" AND "CHARACTER…

  5. Strategies for Value Clarification in Population Education. Abstract-Bibliography Series, Series One, Part Three.

    ERIC Educational Resources Information Center

    Population Center Foundation, Rizal (Philippines). Information and Research Utilization Div.

    This resource bibliography contains abstracts of 67 documents about values clarification in population education. It is the third in a series of three bibliographies for the development of population education programs in the Philippines. Included are abstracts of books, periodical articles, ERIC documents, and unpublished theses. Most of the…

  6. HyFlux - Part I: Regional Modeling of Methane Flux From Near-Seafloor Gas Hydrate Deposits on Continental Margins

    NASA Astrophysics Data System (ADS)

    MacDonald, I. R.; Asper, V.; Garcia, O. P.; Kastner, M.; Leifer, I.; Naehr, T.; Solomon, E.; Yvon-Lewis, S.; Zimmer, B.

    2008-12-01

    HyFlux - Part I: Regional modeling of methane flux from near-seafloor gas hydrate deposits on continental margins MacDonald, I.R., Asper, V., Garcia, O., Kastner, M., Leifer, I., Naehr, T.H., Solomon, E., Yvon-Lewis, S., and Zimmer, B. The Dept. of Energy National Energy Technology Laboratory (DOE/NETL) has recently awarded a project entitled HyFlux: "Remote sensing and sea-truth measurements of methane flux to the atmosphere." The project will address this problem with a combined effort of satellite remote sensing and data collection at proven sites in the Gulf of Mexico where gas hydrate releases gas to the water column. Submarine gas hydrate is a large pool of greenhouse gas that may interact with the atmosphere over geologic time to affect climate cycles. In the near term, the magnitude of methane reaching the atmosphere from gas hydrate on continental margins is poorly known because 1) gas hydrate is exposed to metastable oceanic conditions in shallow, dispersed deposits that are poorly imaged by standard geophysical techniques and 2) the consumption of methane in marine sediments and in the water column is subject to uncertainty. The northern GOM is a prolific hydrocarbon province where rapid migration of oil, gases, and brines from deep subsurface petroleum reservoirs occurs through faults generated by salt tectonics. Focused expulsion of hydrocarbons is manifested at the seafloor by gas vents, gas hydrates, oil seeps, chemosynthetic biological communities, and mud volcanoes. Where hydrocarbon seeps occur in depths below the hydrate stability zone (~500m), rapid flux of gas will feed shallow deposits of gas hydrate that potentially interact with water column temperature changes; oil released from seeps forms sea-surface features that can be detected in remote-sensing images. The regional phase of the project will quantify verifiable sources of methane (and oil) the Gulf of Mexico continental margin and selected margins (e.g. Pakistan Margin, South China Sea

  7. Effects of Hofmeister salt series on gluten network formation: Part I. Cation series.

    PubMed

    Tuhumury, H C D; Small, D M; Day, L

    2016-12-01

    Different cationic salts were used to investigate the effects of the Hofmeister salt series on gluten network formation. The effects of cationic salts on wheat flour dough mixing properties, the rheological and the chemical properties of the gluten extracted from the dough with different respective salts, were investigated. The specific influence of different cationic salts on the gluten structure formation during dough mixing, compared to the sodium ion, were determined. The effects of different cations on dough and gluten of different flours mostly followed the Hofmeister series (NH4(+), K(+), Na(+), Mg(2+) and Ca(2+)). The impacts of cations on gluten structure and dough rheology at levels tested were relatively small. Therefore, the replacement of sodium from a technological standpoint is possible, particularly by monovalent cations such as NH4(+), or K(+). However the levels of replacement need to take into account sensory attributes of the cationic salts.

  8. Simulations of Methane Hydrate Phenomena Over Geologic Timescales. Part I: Effect of Sediment Compaction Rates on Methans Hydrate and Free Gas Accumulation

    SciTech Connect

    Gering, Kevin Leslie

    2003-01-01

    The focus of this work is a model that describes migration and biogenic formation of methane under conditions representative of dynamic marine basins, and the conversion of soluble methane into either solid hydrate or exsolved gas. Incorporated into the overall model are an accurate phase equilibria model for seawater-methane, a methane source term based on biogenesis data, and a sediment compaction model based on porosity as a function of position, time, and the local volume fractions of hydrate solids and free gas. Simulations have shown that under some compaction scenarios, liquid overpressures reach the lithostatic limit due to permeability constraints, which can diminish the advective transfer of soluble methane within the porous sediment. As such, the formation of methane hydrate can be somewhat of a self-moderating process. The occurrence and magnitude of hydrate formation is directly tied to fundamental parameters such as the compaction/sedimentation rates, liquid advection rates, seafloor depth, geothermal gradient, etc. Results are shown for simulations covering 20 million years, wherein growth profiles for methane hydrate and free gas (neither exceeding 10 vol% at any location) are tracked within a vertical sediment column spanning over 3000 m. A case study is also presented for the Blake Ridge region (Ocean Drilling Program Leg 164, Sites 994, 995, and 997) based on simulations covering 6 Ma, wherein it is concluded that methane migration from compaction-driven advection may account for 15-30% of the total hydrate mass present in this region.

  9. Effects of Hofmeister salt series on gluten network formation: Part II. Anion series.

    PubMed

    Tuhumury, H C D; Small, D M; Day, L

    2016-12-01

    Different anion salts from the Hofmeister series were used to investigate their effects on gluten network formation. The effects of these anion salts on the mixing properties of the dough and the rheological and chemical properties of gluten samples extracted from the dough with these respective salts were compared. The aim of this work was to determine how different anion salts influence the formation of the gluten structure during dough mixing. It was found that the Hofmeister anion salts affected the gluten network formation by interacting directly with specific amino acid residues that resulted in changes in gluten protein composition, specifically the percentage of the unextractable polymeric protein fractions (%UPP). These changes consequently led to remarkable differences in the mixing profiles and microstructural features of the dough, small deformation rheological properties of the gluten and a strain hardening behaviour of both dough and gluten samples.

  10. Calculations of automatic chamber flux measurements of methane and carbon dioxide using short time series of concentrations

    NASA Astrophysics Data System (ADS)

    Pirk, Norbert; Mastepanov, Mikhail; Parmentier, Frans-Jan W.; Lund, Magnus; Crill, Patrick; Christensen, Torben R.

    2016-02-01

    The closed chamber technique is widely used to measure the exchange of methane (CH4) and carbon dioxide (CO2) from terrestrial ecosystems. There is, however, large uncertainty about which model should be used to calculate the gas flux from the measured gas concentrations. Due to experimental uncertainties the simple linear regression model (first-order polynomial) is often applied, even though theoretical considerations of the technique suggest the application of other, curvilinear models. High-resolution automatic chamber systems which sample gas concentrations several hundred times per flux measurement make it possible to resolve the curvilinear behavior and study the information imposed by the natural variability of the temporal concentration changes. We used more than 50 000 such flux measurements of CH4 and CO2 from five field sites located in peat-forming wetlands ranging from 56 to 78° N to quantify the typical differences between flux estimates of different models. In addition, we aimed to assess the curvilinearity of the concentration time series and test the general applicability of curvilinear models. Despite significant episodic differences between the calculated flux estimates, the overall differences are generally found to be smaller than the local flux variability on the plot scale. The curvilinear behavior of the gas concentrations within the chamber is strongly influenced by wind-driven chamber leakage, and less so by changing gas concentration gradients in the soil during chamber closure. Such physical processes affect both gas species equally, which makes it possible to isolate biochemical processes affecting the gases differently, such as photosynthesis limitation by chamber headspace CO2 concentrations under high levels of incoming solar radiation. We assess the possibility to exploit this effect for a partitioning of the net CO2 flux into photosynthesis and ecosystem respiration as an example of how high-resolution automatic chamber

  11. National Library Service of the Library of Congress: New Electronic Information Projects. Part Four of a Four-Part Series.

    ERIC Educational Resources Information Center

    McNulty, Tom, Ed.

    1995-01-01

    This final installment of a four-part series on the National Library Service (NLS) examines recently implemented and future projects, with a focus on alternative formats for patrons with disabilities. Discusses LOCIS, the Library of Congress online public access catalog; MARVEL, the Library of Congress gopher; the NLS Web site; and computer disk…

  12. MONGOLS OF THE TWENTIETH CENTURY, PART II. URALIC AND ALTAIC SERIES, VOLUME 37, PART 2.

    ERIC Educational Resources Information Center

    RUPEN, ROBERT A.

    THIS BIBLIOGRAPHY DIRECTLY SUPPLEMENTS AND IS INTENDED AS AN INTEGRAL PART OF "MONGOLS OF THE TWENTIETH CENTURY, PART I." THE RANGE OF SUBJECT MATTER, HOWEVER, GOES FAR BEYOND THE SPECIFIC CONCERNS OF THE FIRST VOLUME, COVERING GENERAL AND SPECIFIC BIBLIOGRAPHIES, UNSIGNED REPORTS AND DOCUMENTS, ENCYCLOPEDIAS, OFFICIAL HISTORIES,…

  13. Time-series measurements of methane (CH4) distribution during open water and ice-cover in lakes throughout the Mackenzie River Delta (Canada)

    NASA Astrophysics Data System (ADS)

    McIntosh, H.; Lapham, L.; Orcutt, B.; Wheat, C. G.; Lesack, L.; Bergstresser, M.; Dallimore, S. R.; MacLeod, R.; Cote, M.

    2016-12-01

    Arctic lakes are known to emit large amounts of methane to the atmosphere and their importance to the global methane (CH4) cycle has been recognized. It is well known CH4 builds up in Arctic lakes during ice-cover, but the amount of and when the CH4 is released to the atmosphere is not well known. Our preliminary results suggest the largest flux of CH4 from lakes to the atmosphere occurs slightly before complete ice-out; while others have shown the largest flux occurs when lakes overturn in the spring. During ice-out, CH4 can also be oxidized by methane oxidizing bacteria before it can efflux to the atmosphere from the surface water. In order to elucidate the processes contributing to Arctic lake CH4 emissions, continuous, long-term and large scale spatial sampling is required; however it is difficult to achieve in these remote locations. We address this problem using two sampling techniques. 1) We deployed osmotically powered pumps (OsmoSamplers), which were able to autonomously and continuously collect lake bottom water over the course of a year from multiple lakes in the Mackenzie River Delta. OsmoSamplers were placed in four lakes in the mid Delta near Inuvik, Northwest Territories, Canada, two lakes in the outer Delta, and two coastal lakes on Richard's Island in 2015. The dissolved CH4 concentration, stable isotope content of CH4 (δ13C-CH4), and dissolved sulfate concentrations in bottom water from these lakes will be presented to better understand methane dynamics under the ice and over time. 2) Along with the time-series data, we will also present data from discrete samples collected from 40 lakes in the mid Delta during key time periods, before and immediately after the spring ice-out. By determining the CH4 dynamics throughout the year we hope to improve predictions of how CH4 emissions may change in a warming Arctic environment.

  14. Part 1 of a 4-part series Facial Cosmetics: Trends and Alternatives

    PubMed Central

    Jacob, Sharon; Katta, Rajani; Nedorost, Susan; Warshaw, Erin; Zirwas, Matt; Cha, Christina

    2011-01-01

    Objective: To provide updated data on usage of ingredients that are common potential contact allergens in several categories of facial cosmetics. To identify useful alternative products with few or no common contact allergens. Design: In November 2009, the full ingredient lists of 5,416 skin, hair, and cosmetic products marketed by the CVS pharmacy chain were copied from CVS.com into Microsoft Word format for analysis. Computer searches were made in Microsoft Word using search/replace and sorting functions to accurately identify the presence of specific allergens in each website product. Measurements: Percentages of American Contact Alternatives Group core series allergens were calculated. Results: The usage of American Contact Alternatives Group core series allergens in facial cosmetics is reported along with suitable alternative products for individuals with contact allergy. Conclusion: Data on allergen usage and alternatives for facial cosmetics is not widely published. This article reviews some of the common potential allergens in facial cosmetics, including blushers and bronzers, concealers, eyeliners, eyeshadows, foundations, loose and pressed powders, and mascaras. Suitable available alternative products for patients with contact allergy are listed. PMID:21779413

  15. Part 3 of a 4-part series Lip and Common Dental Care Products: Trends and Alternatives

    PubMed Central

    Jacob, Sharon; Katta, Rajani; Nedorost, Susan; Warshaw, Erin; Zirwas, Matt; Kruk, Ann

    2011-01-01

    Objective: To provide updated data on the use of ingredients that are common potential contact allergens in several categories of lip and oral products. To identify useful alternative products with few or no common contact allergens. Design: In November 2009, the full ingredient lists of 5,416 skin, hair, and cosmetic products marketed by the CVS pharmacy chain was copied from CVS.com into Microsoft Word format for analysis. Computer searches were made in Microsoft Word using search/replace and sorting functions to accurately identify the presence of specific allergens in each website product. Measurements: Percentages of American Contact Dermatitis Society core series allergens (and other common preservatives) were calculated. Results: The use of American Contact Dermatitis Society core series allergens (and other preservatives) in various categories of lip and oral products are reported. Conclusion: Data on allergens and alternatives for lip and oral products is not widely published. This article reviews some of the common potential allergens in lip liners, lipsticks, lip moisturizers, mouthwashes, and toothpastes. Suitable available alternative products for patients with contact allergy are listed. PMID:21938270

  16. Up with methane

    SciTech Connect

    Barlaz, M.A.; Milke, M.W.; Ham, R.K.

    1986-12-01

    Methane production from municipal refuse represents a rapidly developing source of energy which remains underutilized. Part of the problem is the small amount of methane which is typically collected relative to the refuse's methane generation potential. This study was undertaken to define the parameters which affect the onset of methane production and methane yields in sanitary landfills. Ultimately, we need to develop refuse disposal methods which enhance its methane production potential. Included in the study were tests of how introduction of old refuse, use of sterile cover soil, addition of acetate to refuse, and use of leachate, recycling and neutralization affect methane generation. A more thorough understanding of how the microbes present in refuse react to different variables is the first step in the development of techniques for stimulating methane production in sanitary landfills.

  17. Electronic health records: future clinical applications. Part 2 in a two-part series.

    PubMed

    Wang, Robert; Dugel, Pravin U

    2013-11-01

    In this second installment of his two-part column on electronic health records, Dr. Robert Wang addresses the ways in which EHRs can enhance clinical operations. He explores how to improve revenue and efficiency by enlisting an EHR system to facilitate charting, coding, ICD-10 implementation, patient flow, and meaningful use submission.

  18. Redefining the School District in Tennessee. Part One of a Three-Part Series

    ERIC Educational Resources Information Center

    Smith, Nelson

    2013-01-01

    As the challenges of education governance loom ever larger and the dysfunction and incapacity of the traditional K-12 system reveal themselves as major roadblocks to urgently needed reforms across that system, many have asked, "What's the alternative?" Part of the answer is the Recovery School District, a new state-created entity that…

  19. Transcontinental methane measurements: Part 1. A mobile surface platform for source investigations

    NASA Astrophysics Data System (ADS)

    Farrell, Paige; Culling, Daniel; Leifer, Ira

    2013-08-01

    The potent greenhouse gas, methane, CH4, originates from a wide range of anthropogenic and natural sources. A ground-based, satellite-scale, transcontinental (Florida to California) survey was conducted to understand better emissions from key sources including wetlands, forest fire, and geologic sources, as well as to acquire desert background values and lower atmosphere vertical profiling in the San Bernardino Mountains. A total of 6600 measurements along 7020 km of roadways were made by flame ion detection, gas chromatography (GC) onboard a recreational vehicle in 2010, and during a second survey with a cavity ring-down spectrometer system in Southern California in 2012. Significant vibration reduction efforts allowed near continuous mobile GC measurements. Nocturnal CH4 measurements tended to be higher compared to daytime values, sometime significantly, for similar sources and were concluded due to day/night meteorological differences. The lowest GC observations were 1.80 ppm, observed in the California desert, ˜60 ppb less than minimum desert CH4 observed in 2012. Thanks to smoke visualization of a brush fire plume, the flux from the fire was estimated at 0.15 kiloton day-1. Geologic CH4 emissions from the La Brea tar pit and surrounding areas were surprisingly strong, with peak concentrations of nearly 50 ppm and highly elevated CH4 concentrations extending over at least ˜100 km2, and accounting potentially for a significant fraction of the LA basin CH4 emissions. Geologic CO2 emissions also were observed.

  20. Transcontinental methane measurements: Part 2. Mobile surface investigation of fossil fuel industrial fugitive emissions

    NASA Astrophysics Data System (ADS)

    Leifer, Ira; Culling, Daniel; Schneising, Oliver; Farrell, Paige; Buchwitz, Michael; Burrows, John P.

    2013-08-01

    The potent greenhouse gas, methane, CH4, has a wide variety of anthropogenic and natural sources. Fall, continental-scale (Florida to California) surface CH4 data were collected to investigate the importance of fossil fuel industrial (FFI) emissions in the South US. A total of 6600 measurements along 7020-km of roadways were made by flame ion detection gas chromatography onboard a nearly continuously moving recreational vehicle in 2010. A second, winter survey in Southern California measured CH4 at 2 Hz with a cavity ring-down spectrometer in 2012. Data revealed strong and persistent FFI CH4 sources associated with refining, oil/gas production, a presumed major pipeline leak, and a coal loading plant. Nocturnal CH4 mixing ratios tended to be higher than daytime values for similar sources, sometimes significantly, which was attributed to day/night meteorological differences, primarily changes in the boundary layer height. The highest CH4 mixing ratio (39 ppm) was observed near the Kern River Oil Field, California, which uses steam reinjection. FFI CH4 plume signatures were distinguished as stronger than other sources on local scales. On large (4°) scales, the CH4 trend was better matched spatially with FFI activity than wetland spatial patterns. Qualitative comparison of surface data with SCIAMACHY and GOSAT satellite retrievals showed agreement of the large-scale CH4 spatial patterns. Comparison with inventory models and seasonal winds suggests for some seasons and some portions of the Gulf of Mexico a non-negligible underestimation of FFI emissions. For other seasons and locations, qualitative interpretation is not feasible. Unambiguous quantitative source attribution is more complex, requiring transport modeling.

  1. Lecture Series "Boundary Layer Theory". Part I - Laminar Flows. Part 1; Laminar Flows

    NASA Technical Reports Server (NTRS)

    Schlichting, H.

    1949-01-01

    In the lecture series starting today author want to give a survey of a field of aerodynamics which has for a number of years been attracting an ever growing interest. The subject is the theory of flows with friction, and, within that field, particularly the theory of friction layers, or boundary layers. A great many considerations of aerodynamics are based on the ideal fluid, that is the frictionless incompressibility and fluid. By neglect of compressibility and friction the extensive mathematical theory of the ideal fluid, (potential theory) has been made possible. Actual liquids and gases satisfy the condition of incomressibility rather well if the velocities are not extremely high or, more accurately, if they are small in comparison with sonic velocity. For air, for instance, the change in volume due to compressibility amounts to about 1 percent for a velocity of 60 meters per second. The hypothesis of absence of friction is not satisfied by any actual fluid; however, it is true that most technically important fluids, for instance air and water, have a very small friction coefficient and therefore behave in many cases almost like the ideal frictionless fluid. Many flow phenomena, in particular most cases of lift, can be treated satisfactorily, - that is, the calculations are in good agreement with the test results, -under the assumption of frictionless fluid. However, the calculations with frictionless flow show a very serious deficiency; namely, the fact, known as d'Alembert's paradox, that in frictionless flow each body has zero drag whereas in actual flow each body experiences a drag of greater or smaller magnitude. For a long time the theory has been unable to bridge this gap between the theory of frictionless flow and the experimental findings about actual flow. The cause of this fundamental discrepancy is the viscosity which is neglected in the theory of ideal fluid; however, in spite of its extraordinary smallness it is decisive for the course of the flow

  2. Measuring In situ Dissolved Methane Concentrations in Gas Hydrate-Rich Systems. Part 2: Investigating Mechanisms Controlling Hydrate Dissolution

    NASA Astrophysics Data System (ADS)

    Wilson, R. M.; Lapham, L.; Riedel, M.; Chanton, J.

    2010-12-01

    Methane is a potent greenhouse gas, twenty times more infrared-active than CO2, and an important energy source. For these reasons, methane hydrate, one of the largest potential reservoirs of methane on earth, is of considerable interest to scientists and industry alike. In particular, questions relating to the stability of methane hydrate are becoming more important as concern about the release of methane into overlying ocean (and eventually the atmosphere) and interest in the recovery of methane from this resource increase. Three primary factors control hydrate stability: pressure (P), temperature (T), and the gas concentration in the surrounding environment. Pressure and temperature govern the stability of the hydrate structure. When hydrate is exposed to P/T regimes outside of the stability zone (HSZ), the hydrate decomposes by dissociation, a relatively fast process resulting in the release of gaseous phase methane (CH4(g)). However, if the P/T regime is within the HSZ, but the concentration of the guest gas (typically CH4) in the surroundings is below saturation, the hydrate will decompose by dissolution resulting in a phase change between hydrate and the dissolved gas phase (CH4(aq)). OsmoSamplers were deployed at a methane hydrate outcrop in Barkley Canyon, Northern Cascadia Margin, collecting porewater samples in a gradient at 1cm increments away from the hydrate surface. Methane, ethane, and propane concentrations in the porewater samples were measured at 6-day resolution over a period of 9 months. At three centimeters from the hydrate face, methane concentrations were significantly lower than predicted saturation for conditions at this site. Curiously, in situ observations of natural hydrate dissolution are up to two orders of magnitude lower than predicted diffusion-controlled dissolution based on surrounding methane concentrations. Since diffusion of methane away from the hydrate surface has been implicated as the dominant control of hydrate dissolution

  3. Getting "Ready" for an Emergency: Emergency Preparedness Series--Part 3

    ERIC Educational Resources Information Center

    Apel, Laura

    2009-01-01

    This article presents part 3 of a series of articles giving timely information about potential emergency situations and offering suggestions and new technology that exceptional families can use to prepare for emergencies--everything from localized to large scale emergencies, everything from natural disasters to terrorist attacks. In 2003 the…

  4. Getting "Ready" for an Emergency: Emergency Preparedness Series--Part 3

    ERIC Educational Resources Information Center

    Apel, Laura

    2009-01-01

    This article presents part 3 of a series of articles giving timely information about potential emergency situations and offering suggestions and new technology that exceptional families can use to prepare for emergencies--everything from localized to large scale emergencies, everything from natural disasters to terrorist attacks. In 2003 the…

  5. Characterizing Methane Emissions at Local Scales with a 20 Year Total Hydrocarbon Time Series, Imaging Spectrometry, and Web Facilitated Analysis

    NASA Astrophysics Data System (ADS)

    Bradley, Eliza Swan

    Methane is an important greenhouse gas for which uncertainty in local emission strengths necessitates improved source characterizations. Although CH4 plume mapping did not motivate the NASA Airborne Visible InfraRed Imaging Spectrometer (AVIRIS) design and municipal air quality monitoring stations were not intended for studying marine geological seepage, these assets have capabilities that can make them viable for studying concentrated (high flux, highly heterogeneous) CH4 sources, such as the Coal Oil Point (COP) seep field (˜0.015 Tg CH4 yr-1) offshore Santa Barbara, California. Hourly total hydrocarbon (THC) data, spanning 1990 to 2008 from an air pollution station located near COP, were analyzed and showed geologic CH4 emissions as the dominant local source. A band ratio approach was developed and applied to high glint AVIRIS data over COP, resulting in local-scale mapping of natural atmospheric CH4 plumes. A Cluster-Tuned Matched Filter (CTMF) technique was applied to Gulf of Mexico AVIRIS data to detect CH4 venting from offshore platforms. Review of 744 platform-centered CTMF subsets was facilitated through a flexible PHP-based web portal. This dissertation demonstrates the value of investigating municipal air quality data and imaging spectrometry for gathering insight into concentrated methane source emissions and highlights how flexible web-based solutions can help facilitate remote sensing research.

  6. Mitigation of methane and nitrous oxide emissions from animal operations: III. A review of animal management mitigation options

    USDA-ARS?s Scientific Manuscript database

    The goal of this review was to analyze published data on animal management practices that mitigate enteric methane and nitrous oxide emissions from animal operations. The review is part of a series of reports evaluating methane and nitrous oxide mitigation practices for livestock operations commissi...

  7. Wavelet Analysis of the Periodicity and Correlation of the 420-ka Temperature, Carbon Dioxide, and Methane Time Series from the Vostok Ice Core

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Huang, S.

    2010-12-01

    A good understanding of the history of Earth’s surface temperature and the excursion of atmospheric greenhouse gas composition is of crucial importance in reasoning the course and causes of climate change. However, identifying the variation and correspondence of different climate variables has been a challenging task due to the noisy, complex, and non-linear nature of paleoclimate records. Here we use wavelet technique to revisit the 420-ka temperature, carbon dioxide, and methane records from the ice core of Vostok station in East Antarctica [Petit et al., 1999, Nature, 399, 429] for the periodicity of and the correlation among these three variables. As with many other paleoclimate records, the sampling intervals of the Vostok records are different from variable to variable and from time to time. To allow for the application of continuous Morlet wavelet transform, cross-wavelet transform, and cross-wavelet coherence techniques, all three records were interpolated into 500-year equal interval time series with a cubic polynomial interpolation scheme. All three time series demonstrate the orbital eccentricity oscillation of about 100-ka as the most significant period with a lengthening trend towards the present day. Another periodicity common to all three records is the orbital tilt period of about 41 ka. However, the about 21 ka precession period can only be identified in the methane time series in the Morlet wavelet power spectrum. Our analysis further shows that temperature, CO2, and CH4 are well correlated, whereas the linkage of temperature with CO2 is stranger than that of temperature with CH4 and CO2 with CH4. In pairwise cross-wavelet transform and cross-wavelet coherence diagrams, almost all significant sections show in-phase correlations. Generally, the fluctuations of CO2 and CH4 appear to be either in sync with or slightly led by temperature variation, although there are isolated slots of millennium scales when the temperature - greenhouse gas

  8. Selective desorption of carbon dioxide from sewage sludge for in situ methane enrichment--Part II: Modelling and evaluation of experiments.

    PubMed

    Lindberg, Anna; Rasmuson, Ake C

    2007-08-01

    In situ methane enrichment in anaerobic digestion of sewage sludge has been investigated by experiments and by modelling. Sludge from a full scale digester was fed to a pilot scale bubble column having 0.3 m diameter for preferential desorption of carbon dioxide. In this second part, a model describing the steady-state performance of the bubble column for desorption of carbon dioxide and methane has been developed. The column is assumed to operate in the homogeneous flow regime, and with respect to carbon dioxide and methane both phases are described by the axial dispersion model. The model treats the chemical reaction equilibrium between carbon dioxide and bicarbonate as being slow and the bicarbonate concentration as being constant. The model is correlated to previously reported experimental results to determine the liquid side mass transfer coefficient in each experiment. A simple power law model is used to correlate the mass transfer coefficient to the gas flow rate. In general, the model allows for a reasonable qualitative description of the behaviour of the bubble column performance but the quantitative agreement with experimental results is not satisfactory. It is believed, though that the main problem is actually not in the model but is related to experimental uncertainties concerning inlet concentrations of liquid phase methane and bicarbonate.

  9. IUPAC-NIST Solubility Data Series. 95. Alkaline Earth Carbonates in Aqueous Systems. Part 2. Ca

    NASA Astrophysics Data System (ADS)

    Vanderdeelen, Jan

    2012-06-01

    The alkaline earth carbonates are an important class of minerals. This article is part of a volume in the IUPAC-NIST Solubility Data Series that compiles and critically evaluates solubility data of the alkaline earth carbonates in water and in simple aqueous electrolyte solutions. Part 1 outlined the procedure adopted in this volume, and presented the beryllium and magnesium carbonates. Part 2, the current paper, compiles and critically evaluates the solubility data of calcium carbonate. The chemical forms included are the anhydrous CaCO3 types calcite, aragonite, and vaterite, the monohydrate monohydrocalcite (CaCO3. H2O), the hexahydrate ikaite (CaCO3.6H2O), and an amorphous form. The data were analyzed with two model variants, and thermodynamic data of each form consistent with each of the models and with the CODATA key values for thermodynamics are presented.

  10. IUPAC-NIST Solubility Data Series. 95. Alkaline Earth Carbonates in Aqueous Systems. Part 2. Ca

    SciTech Connect

    De Visscher, Alex; Vanderdeelen, Jan

    2012-06-15

    The alkaline earth carbonates are an important class of minerals. This article is part of a volume in the IUPAC-NIST Solubility Data Series that compiles and critically evaluates solubility data of the alkaline earth carbonates in water and in simple aqueous electrolyte solutions. Part 1 outlined the procedure adopted in this volume, and presented the beryllium and magnesium carbonates. Part 2, the current paper, compiles and critically evaluates the solubility data of calcium carbonate. The chemical forms included are the anhydrous CaCO{sub 3} types calcite, aragonite, and vaterite, the monohydrate monohydrocalcite (CaCO{sub 3}{center_dot} H{sub 2}O), the hexahydrate ikaite (CaCO{sub 3}{center_dot}6H{sub 2}O), and an amorphous form. The data were analyzed with two model variants, and thermodynamic data of each form consistent with each of the models and with the CODATA key values for thermodynamics are presented.

  11. Water Under Fire: A Seven Part Video Series on Canada's Water

    NASA Astrophysics Data System (ADS)

    Mrazek, R.; Byrne, J.; Rabe, N.; Gallant, G.

    2003-12-01

    Canada's water is under escalating pressure from a host of threats. Increasingly, our water is being tainted, misused and over allocated. Experts have identified a multitude of threats to water quantity and quality. Among them, climate change impacts on water supply, and the effects of pesticides, pathogens, industrial waste, urban runoff, and rising demands. These and other threats are the roots to a serious shortage of high quality, safe water sources. In the 1990s, waterborne diseases have re-emerged as one of the primary health issues on a national and global scale. This seven-part video series brings science voices together and provides a nationwide context. The first six programs in the series explore regional concerns: Rocky Mountains, Prairie Waters, Northern Waters, Great Lakes Basin, St. Lawrence and Atlantic Canada. The final program covers the national and international perspectives.

  12. Basic Biology of Oxidative Stress and the Cardiovascular System: Part 1 of a 3-Part Series.

    PubMed

    Sack, Michael N; Fyhrquist, Frej Y; Saijonmaa, Outi J; Fuster, Valentin; Kovacic, Jason C

    2017-07-11

    The generation of reactive oxygen species (ROS) is a fundamental aspect of normal human biology. However, when ROS generation exceeds endogenous antioxidant capacity, oxidative stress arises. If unchecked, ROS production and oxidative stress mediate tissue and cell damage that can spiral in a cycle of inflammation and more oxidative stress. This article is part 1 of a 3-part series covering the role of oxidative stress in cardiovascular disease. The broad theme of this first paper is the mechanisms and biology of oxidative stress. Specifically, the authors review the basic biology of oxidative stress, relevant aspects of mitochondrial function, and stress-related cell death pathways (apoptosis and necrosis) as they relate to the heart and cardiovascular system. They then explore telomere biology and cell senescence. As important regulators and sensors of oxidative stress, telomeres are segments of repetitive nucleotide sequence at each end of a chromosome that protect the chromosome ends from deterioration. Copyright © 2017 American College of Cardiology Foundation. All rights reserved.

  13. Calculations of automatic chamber flux measurements of methane and carbon dioxide using short time series of concentrations

    NASA Astrophysics Data System (ADS)

    Pirk, N.; Mastepanov, M.; Parmentier, F.-J. W.; Lund, M.; Crill, P.; Christensen, T. R.

    2015-09-01

    The closed chamber technique is widely used to measure the exchange of methane (CH4) and carbon dioxide (CO2) from terrestrial ecosystems. There is, however, large uncertainty about which model should be used to calculate the gas flux from the measured gas concentrations. Due to experimental uncertainties the robust linear regression model (first order polynomial) is often applied, even though theoretical considerations of the technique suggest the application of other, curvilinear models. High-resolution automatic chamber systems which sample gas concentrations several hundred times per flux measurement make it possible to resolve the curvilinear behavior and study the information imposed by the natural variability of the temporal concentration changes. We used more than 50 000 such flux measurements of CH4 and CO2 from five field sites located in peat forming wetlands to calculate fluxes with different models. The flux differences from independent linear estimates are generally found to be smaller than the local flux variability on the plot scale. The curvilinear behavior of the gas concentrations within the chamber is strongly influenced by wind driven chamber leakage, and less so by changing gas concentration gradients in the soil during chamber closure. Such physical processes affect both gas species equally, which makes it possible to isolate biochemical processes affecting the gases differently, such as photosynthesis limitation by chamber headspace CO2 concentrations under high levels of incoming solar radiation. We assess the possibility to exploit this effect for a partitioning of the net CO2 flux into photosynthesis and ecosystem respiration and argue that high-resolution automatic chamber measurements could be used for purposes beyond the estimation of the net gas flux.

  14. ZnO Functionalization of Multi-walled Carbon Nanotubes for Methane Sensing at Single Parts Per Million Concentration Levels

    EPA Science Inventory

    This paper presents a novel atomic layer deposition (ALD) based ZnO functionalization of surface pre-treated multi-walled carbon nanotubes (MWCNTs) for highly sensitive methane chemoresistive sensors. The temperature optimization of the ALD process leads to enhanced ZnO nanopart...

  15. ZnO Functionalization of Multi-walled Carbon Nanotubes for Methane Sensing at Single Parts Per Million Concentration Levels

    EPA Science Inventory

    This paper presents a novel atomic layer deposition (ALD) based ZnO functionalization of surface pre-treated multi-walled carbon nanotubes (MWCNTs) for highly sensitive methane chemoresistive sensors. The temperature optimization of the ALD process leads to enhanced ZnO nanopart...

  16. (Atmospheric methane research program for a study in China)

    SciTech Connect

    Not Available

    1991-01-01

    The most significant results of recent research are the findings (1) that methane emissions from rice paddies are strongly dependent on the soil temperature, and (2) that the fluxes of methane from the Chinese rice paddies are up to 10 times greater on average compared with fluxes from rice paddies in other parts of the world. In addition to the main findings there are a number of other significant results. These are: (1) the extension of a time series of concentrations of methane (and also of other gases) at Minqin. The data now span sufficiently long times to estimate trends and seasonal variations and to include Minqin in our global flask sampling network. (2) We have completed further work on bio-gas pits. (3) We have also measured methane in Beijing and found relatively low concentrations for an urban area. 8 figs.

  17. The SPASIBA force field of aldehydes. Part I: Structure and vibrational wavenumbers of methanal, ethanal and propanal

    NASA Astrophysics Data System (ADS)

    Zanoun, A.; Durier, V.; Belaidi, A.; Vergoten, G.

    1999-02-01

    The SPASIBA vibrational spectroscopic force field has been developed for the aldehyde function. The tested molecules are methanal, ethanal, propanal and some of their deuterated analogues. The parameters have been obtained by fitting calculated and observed vibrational wavenumbers. A set of 34 independant force constants has been found to correctly describe the structure and vibrational spectra. The average error between predicted and observed vibrational wavenumber is 16 cm -1.

  18. The 1992-1993 advanced design program. Part 1: The Mars methane engine project. Part 2: The Mars oxygen processor new furnace

    NASA Technical Reports Server (NTRS)

    Lauer, Stephen; Hoover, Scott; Lawrence, Lori; Paparistodemou, Christos; Taylor, Doug

    1993-01-01

    Three constituents of the Martian atmosphere, methane, carbon dioxide, and oxygen, can be used for internal combustion in engines utilized for future space exploration on Mars. These three gases, considered as the test case in this research, will be examined to determine required flow rates needed for combustion and optimization of engine performance. Results of the test case are examined in relation to a base case of methane and air for comparative purposes. Testing of exhaust temperatures, cylinder pressure, and exhaust gas analysis were performed for the base case and test case. Also described is a study utilizing a zirconia cell to convert carbon dioxide into usable oxygen to help support future Mars missions.

  19. The 1992-1993 advanced design program. Part 1: The Mars methane engine project. Part 2: The Mars oxygen processor new furnace

    NASA Astrophysics Data System (ADS)

    Lauer, Stephen; Hoover, Scott; Lawrence, Lori; Paparistodemou, Christos; Taylor, Doug

    1993-04-01

    Three constituents of the Martian atmosphere, methane, carbon dioxide, and oxygen, can be used for internal combustion in engines utilized for future space exploration on Mars. These three gases, considered as the test case in this research, will be examined to determine required flow rates needed for combustion and optimization of engine performance. Results of the test case are examined in relation to a base case of methane and air for comparative purposes. Testing of exhaust temperatures, cylinder pressure, and exhaust gas analysis were performed for the base case and test case. Also described is a study utilizing a zirconia cell to convert carbon dioxide into usable oxygen to help support future Mars missions.

  20. Methane formation and methane oxidation by methanogenic bacteria.

    PubMed Central

    Zehnder, A J; Brock, T D

    1979-01-01

    Methanogenic bacteria were found to form and oxidize methane at the same time. As compared to the quantity of methane formed, the amount of methane simultaneously oxidized varied between 0.3 and 0.001%, depending on the strain used. All the nine tested strains of methane producers (Methanobacterium ruminantium, Methanobacterium strain M.o.H., M. formicicum, M. thermoautotrophicum, M. arbophilicum, Methanobacterium strain AZ, Methanosarcina barkeri, Methanospirillum hungatii, and the "acetate organism") reoxidized methane to carbon dioxide. In addition, they assimilated a small part of the methane supplied into cell material. Methanol and acetate also occurred as oxidation products in M. barkeri cultures. Acetate was also formed by the "acetate organism," a methane bacterium unable to use methanogenic substrates other than acetate. Methane was the precursor of the methyl group of the acetate synthesized in the course of methane oxidation. Methane formation and its oxidation were inhibited equally by 2-bromoethanesulfonic acid. Short-term labeling experiments with M. thermoautotrophicum and M. hungatii clearly suggest that the pathway of methane oxidation is not identical with a simple back reaction of the methane formation process. Images PMID:762019

  1. Time-series analysis for the episodic production and transport of methane from the Glacial Lake Agassiz peatlands, northern Minnesota. Final report

    SciTech Connect

    Siegel, D.I.

    1998-01-01

    The large peat basins of North America are an important reservoir in the global carbon cycle and a significant source of atmospheric methane. The authors investigated carbon cycling in the Glacial Lake Agassiz peatlands (GLAP) of Minnesota. Initially in 1990, they identified a dramatic change in the concentration of methane in the pore-waters of the raised bogs in the GLAP during an extreme drought. This methane dissipated when the drought broke in 1991 and the occurrence of deep methane is related to changes in the direction of groundwater flow in the peat column. The production of methane and its diffusive loss to the atmosphere was modeled and was about 10 times less than that measured directly in chambers at the land surface. It is clear from the reversals in hydraulic heat, changes in pore-water chemical composition over time, and paleostratigraphic markers, that regional ground water flow systems that are controlled by climate change are unexpectedly a major control over methanogenesis and carbon cycling in GLAP. Seismic profiles made showed that buried bedrock ridges particularly deflect regional groundwater flow upwards towards the land surface and towards raised bog landforms. In addition, high-resolution GPS measurements from data stations funded by this DOE project have shown this year that the peakland land surface elevation changes daily on a scale of cms, and seasonally on a scale of 10s of cm. This most recent observation is exciting because it may reflect episodic degassing of free phase methane from the peat column to the atmosphere, a source for methane previously unaccounted for by methane researchers.

  2. Oceanographic Data Report for South West Pacific Cruises in the SEAMAP Series. Part 2. Winter Survey Data 1985 to 1987

    DTIC Science & Technology

    1990-06-01

    WSRL-TM-15f AR-OO586 AD-A236 018 DTIC 4N 13913 4 OCEANOGRAPHIC DATA REPORT FOR SOUTH WEST PACIFIC CRUISES IN THE SEAMAP SERIES. PART 2. WINTER SURVEY...WEST PACIFIC CRUISES IN THE SEAMAP SERIES. PART 2. WINTER SURVEY DATA 1985 TO 1987 L.J. Hamilton and J.A. Boyle SUMMARY(U) Six oceanographic surveys...oceanographic parameters known as project SEAMAP . This report presents winier survey data for bathymetry, sea surface temperature, wind speed, sea

  3. Methane Emission by Camelids

    PubMed Central

    Dittmann, Marie T.; Runge, Ullrich; Lang, Richard A.; Moser, Dario; Galeffi, Cordula; Kreuzer, Michael; Clauss, Marcus

    2014-01-01

    Methane emissions from ruminant livestock have been intensively studied in order to reduce contribution to the greenhouse effect. Ruminants were found to produce more enteric methane than other mammalian herbivores. As camelids share some features of their digestive anatomy and physiology with ruminants, it has been proposed that they produce similar amounts of methane per unit of body mass. This is of special relevance for countrywide greenhouse gas budgets of countries that harbor large populations of camelids like Australia. However, hardly any quantitative methane emission measurements have been performed in camelids. In order to fill this gap, we carried out respiration chamber measurements with three camelid species (Vicugna pacos, Lama glama, Camelus bactrianus; n = 16 in total), all kept on a diet consisting of food produced from alfalfa only. The camelids produced less methane expressed on the basis of body mass (0.32±0.11 L kg−1 d−1) when compared to literature data on domestic ruminants fed on roughage diets (0.58±0.16 L kg−1 d−1). However, there was no significant difference between the two suborders when methane emission was expressed on the basis of digestible neutral detergent fiber intake (92.7±33.9 L kg−1 in camelids vs. 86.2±12.1 L kg−1 in ruminants). This implies that the pathways of methanogenesis forming part of the microbial digestion of fiber in the foregut are similar between the groups, and that the lower methane emission of camelids can be explained by their generally lower relative food intake. Our results suggest that the methane emission of Australia's feral camels corresponds only to 1 to 2% of the methane amount produced by the countries' domestic ruminants and that calculations of greenhouse gas budgets of countries with large camelid populations based on equations developed for ruminants are generally overestimating the actual levels. PMID:24718604

  4. Methane emission by camelids.

    PubMed

    Dittmann, Marie T; Runge, Ullrich; Lang, Richard A; Moser, Dario; Galeffi, Cordula; Kreuzer, Michael; Clauss, Marcus

    2014-01-01

    Methane emissions from ruminant livestock have been intensively studied in order to reduce contribution to the greenhouse effect. Ruminants were found to produce more enteric methane than other mammalian herbivores. As camelids share some features of their digestive anatomy and physiology with ruminants, it has been proposed that they produce similar amounts of methane per unit of body mass. This is of special relevance for countrywide greenhouse gas budgets of countries that harbor large populations of camelids like Australia. However, hardly any quantitative methane emission measurements have been performed in camelids. In order to fill this gap, we carried out respiration chamber measurements with three camelid species (Vicugna pacos, Lama glama, Camelus bactrianus; n = 16 in total), all kept on a diet consisting of food produced from alfalfa only. The camelids produced less methane expressed on the basis of body mass (0.32±0.11 L kg⁻¹ d⁻¹) when compared to literature data on domestic ruminants fed on roughage diets (0.58±0.16 L kg⁻¹ d⁻¹). However, there was no significant difference between the two suborders when methane emission was expressed on the basis of digestible neutral detergent fiber intake (92.7±33.9 L kg⁻¹ in camelids vs. 86.2±12.1 L kg⁻¹ in ruminants). This implies that the pathways of methanogenesis forming part of the microbial digestion of fiber in the foregut are similar between the groups, and that the lower methane emission of camelids can be explained by their generally lower relative food intake. Our results suggest that the methane emission of Australia's feral camels corresponds only to 1 to 2% of the methane amount produced by the countries' domestic ruminants and that calculations of greenhouse gas budgets of countries with large camelid populations based on equations developed for ruminants are generally overestimating the actual levels.

  5. Accounting Issues: An Essay Series Part I--Introduction to Accounting Theory and Cash

    ERIC Educational Resources Information Center

    Laux, Judy

    2007-01-01

    Recent accounting scandals challenge academics to refocus the educational process on the theoretical underpinnings of accounting. This is the first in a series of articles designed to facilitate this realignment. Intended as a supplement for the introductory accounting course, the essay series connects each of the primary accounting elements to…

  6. Accounting Issues: An Essay Series Part I--Introduction to Accounting Theory and Cash

    ERIC Educational Resources Information Center

    Laux, Judy

    2007-01-01

    Recent accounting scandals challenge academics to refocus the educational process on the theoretical underpinnings of accounting. This is the first in a series of articles designed to facilitate this realignment. Intended as a supplement for the introductory accounting course, the essay series connects each of the primary accounting elements to…

  7. The negative parts of the sums of sine series with quasimonotonic coefficients

    NASA Astrophysics Data System (ADS)

    Popov, A. Yu.; Solodov, A. P.

    2017-06-01

    It has long been known that the sum of a sine series with positive coefficients tending to zero monotonically is positive in some right half-neighbourhood of zero. The paper investigates whether the sums of series with quasimonotonic coefficients retain this property (or a weaker version of it). Bibliography: 6 titles.

  8. Carbon dioxide and methane measurements from the Los Angeles Megacity Carbon Project - Part 1: calibration, urban enhancements, and uncertainty estimates

    NASA Astrophysics Data System (ADS)

    Verhulst, Kristal R.; Karion, Anna; Kim, Jooil; Salameh, Peter K.; Keeling, Ralph F.; Newman, Sally; Miller, John; Sloop, Christopher; Pongetti, Thomas; Rao, Preeti; Wong, Clare; Hopkins, Francesca M.; Yadav, Vineet; Weiss, Ray F.; Duren, Riley M.; Miller, Charles E.

    2017-07-01

    We report continuous surface observations of carbon dioxide (CO2) and methane (CH4) from the Los Angeles (LA) Megacity Carbon Project during 2015. We devised a calibration strategy, methods for selection of background air masses, calculation of urban enhancements, and a detailed algorithm for estimating uncertainties in urban-scale CO2 and CH4 measurements. These methods are essential for understanding carbon fluxes from the LA megacity and other complex urban environments globally. We estimate background mole fractions entering LA using observations from four extra-urban sites including two marine sites located south of LA in La Jolla (LJO) and offshore on San Clemente Island (SCI), one continental site located in Victorville (VIC), in the high desert northeast of LA, and one continental/mid-troposphere site located on Mount Wilson (MWO) in the San Gabriel Mountains. We find that a local marine background can be established to within ˜ 1 ppm CO2 and ˜ 10 ppb CH4 using these local measurement sites. Overall, atmospheric carbon dioxide and methane levels are highly variable across Los Angeles. Urban and suburban sites show moderate to large CO2 and CH4 enhancements relative to a marine background estimate. The USC (University of Southern California) site near downtown LA exhibits median hourly enhancements of ˜ 20 ppm CO2 and ˜ 150 ppb CH4 during 2015 as well as ˜ 15 ppm CO2 and ˜ 80 ppb CH4 during mid-afternoon hours (12:00-16:00 LT, local time), which is the typical period of focus for flux inversions. The estimated measurement uncertainty is typically better than 0.1 ppm CO2 and 1 ppb CH4 based on the repeated standard gas measurements from the LA sites during the last 2 years, similar to Andrews et al. (2014). The largest component of the measurement uncertainty is due to the single-point calibration method; however, the uncertainty in the background mole fraction is much larger than the measurement uncertainty

  9. Characterization of Methane Degradation and Methane-Degrading Microbes in Alaska Coastal Water

    SciTech Connect

    Kirchman, David L.

    2012-03-29

    The net flux of methane from methane hydrates and other sources to the atmosphere depends on methane degradation as well as methane production and release from geological sources. The goal of this project was to examine methane-degrading archaea and organic carbon oxidizing bacteria in methane-rich and methane-poor sediments of the Beaufort Sea, Alaska. The Beaufort Sea system was sampled as part of a multi-disciplinary expedition (Methane in the Arctic Shelf or MIDAS) in September 2009. Microbial communities were examined by quantitative PCR analyses of 16S rRNA genes and key methane degradation genes (pmoA and mcrA involved in aerobic and anaerobic methane degradation, respectively), tag pyrosequencing of 16S rRNA genes to determine the taxonomic make up of microbes in these sediments, and sequencing of all microbial genes (metagenomes ). The taxonomic and functional make-up of the microbial communities varied with methane concentrations, with some data suggesting higher abundances of potential methane-oxidizing archaea in methane-rich sediments. Sequence analysis of PCR amplicons revealed that most of the mcrA genes were from the ANME-2 group of methane oxidizers. According to metagenomic data, genes involved in methane degradation and other degradation pathways changed with sediment depth along with sulfate and methane concentrations. Most importantly, sulfate reduction genes decreased with depth while the anaerobic methane degradation gene (mcrA) increased along with methane concentrations. The number of potential methane degradation genes (mcrA) was low and inconsistent with other data indicating the large impact of methane on these sediments. The data can be reconciled if a small number of potential methane-oxidizing archaea mediates a large flux of carbon in these sediments. Our study is the first to report metagenomic data from sediments dominated by ANME-2 archaea and is one of the few to examine the entire microbial assemblage potentially involved in

  10. Developing receptor-oriented methods for non-methane hydrocarbon characterisation in urban air. Part II: source apportionment

    NASA Astrophysics Data System (ADS)

    Borbon, Agnès; Fontaine, Hervé; Locoge, Nadine; Veillerot, Marc; Galloo, J. C.

    The methods and the results of non-methane hydrocarbon (NMHC) source apportionment are described at urban scale on a spatial and temporal basis. Here, hourly ambient concentrations of nearly 40 C 2-C 9 NMHC are used. Methods are based on the knowledge of the wintertime NMHC vehicle-exhaust emission ratio generally determined by simple regression analysis taking acetylene, ethylene, propene and 1,3-butadiene as auto-exhaust tracers. The RSD of the estimated source contributions is lower than 20%; the developed receptor-oriented methods are flexible and easily transposable to other areas. In winter, vehicle-exhaust emissions explain 100% of the NMHC majority levels and even isoprene. From May to November, our models revealed the temperature-dependent contribution of additional sources (0.71< r<0.90). On the one hand, the evaporation of fuel and solvent affects the whole C 4-C 9 NMHC fraction, and fluctuates between 20% and 50%, even for a northern France urban area. On the other hand, both vehicle-exhaust and biogenic emissions control the highly photoreactive isoprene distribution whatever the site; the traffic is responsible for a third of its levels in summer. Finally, the particular behaviour of the C 2-C 4 compounds pointed out dominant contributions, generally other than traffic. Suspected sources are numerous: natural gas leakage for ethane and propane, wintertime fuel evaporation for butanes and butenes, non-automotive combustion for ethylene and acetylene. Ethane and propane also showed that long-range advective transport, responsible for background concentrations, could significantly contribute to the hydrocarbon levels with a high atmospheric residence time (from 20% to 50%).

  11. Legal Issues Relating to Part-Time Faculty Employment. Occasional Paper Series No. 6.

    ERIC Educational Resources Information Center

    Head, Ronald B.

    Summarized from a national study of part-time college faculty employment are the legal developments that affect the rights of part-time faculty. The part-timer has long been a marginal employee in academe, but recent developments in the law clarify the degree to which he holds some measure of job security, rights to equal pay, and the protections…

  12. Accounting Issues: An Essay Series Part IV--Property, Plant, & Equipment

    ERIC Educational Resources Information Center

    Laux, Judy

    2007-01-01

    This fourth article in a series of theoretical essays intended to supplement the introductory financial accounting course is dedicated to the topic of property, plant, and equipment (PP&E), including both the accounting treatment and its related conceptual connections. The paper also addresses the measurement dilemmas, scandalous accounting…

  13. Accounting Issues: An Essay Series Part IX--Statement of Cash Flows

    ERIC Educational Resources Information Center

    Laux, Judy

    2009-01-01

    This essay series, beginning with Laux [2007a], defends the proposition that eliminating the theoretical chapter from the principles level accounting course has weakened the introduction for students new to this subject, perhaps resulting in some adverse selection for the accounting profession. As a remedy, it offers concise theoretical articles…

  14. Accounting Issues: An Essay Series Part VI--Investments in Securities

    ERIC Educational Resources Information Center

    Laux, Judy

    2008-01-01

    The sixth in a series of theory-based essays, this article presents accounting for investments in debt and equity securities along with some related conceptual and measurement issues. Additional coverage is devoted to potential ethical dilemmas and both theoretical and empirical literature related to this asset. (Contains 1 footnote.)

  15. NASPE Developed Informational Products and Applications. Article #4 in a 4-Part Series

    ERIC Educational Resources Information Center

    Fisette, Jennifer L.; Placek, Judith H.; Avery, Marybell; Dyson, Ben; Fox, Connie; Franck, Marian; Graber, Kim; Rink, Judith; Zhu, Weimo

    2009-01-01

    This is the fourth and final article in the "PE Metrics" series that focuses on assessing the National Standards for Physical Education (NASPE) for Standard 1. The first article focused on assessment of student learning. The second described formative and summative assessments and provided considerations on how to implement assessment within…

  16. Instructional Considerations for Implementing Student Assessments. Article #2 in a 4-part series

    ERIC Educational Resources Information Center

    Fisette, Jennifer L.; Placek, Judith H.; Avery, Marybell; Dyson, Ben; Fox, Connie; Franck, Marian; Graber, Kim; Rink, Judith; Zhu, Weimo

    2009-01-01

    The first article of the PE Metrics series, "Developing Quality Physical Education through Student Assessments" (January/February 2009 "Strategies" issue) focused on the importance of assessing student learning in relation to NASPE's content standards (NASPE, 2004). The article emphasized that unless students are appropriately assessed, it is…

  17. Accounting Issues: An Essay Series Part IV--Property, Plant, & Equipment

    ERIC Educational Resources Information Center

    Laux, Judy

    2007-01-01

    This fourth article in a series of theoretical essays intended to supplement the introductory financial accounting course is dedicated to the topic of property, plant, and equipment (PP&E), including both the accounting treatment and its related conceptual connections. The paper also addresses the measurement dilemmas, scandalous accounting…

  18. Culture Shock: A Teacher's Guide To Accompany the Four-Part PBS Series Premiering January 2000.

    ERIC Educational Resources Information Center

    Jaffee, Cyrisse, Ed.; Sharma, Amina, Ed.

    This teacher's guide accompanies the four videos ("Born to Trouble: Adventures of Huckleberry Finn"; "The Shock of the Nude: Manet's Olympia"; "Hollywood Censored: Movies, Morality and the Production Code"; and "The Devil's Music: 1920s Jazz") of the PBS "Culture Shock" series. The guide suggests that the videos could be used in the…

  19. Cooperation in Japan. Grades Kindergarten-Third. Elementary Literature Series, Part 1.

    ERIC Educational Resources Information Center

    Mukai, Gary

    The Stanford Program on International and Cross-Cultural Education (SPICE) represents a long-term effort by Stanford University to improve international and cross-cultural education in elementary and secondary schools. This volume of the elementary literature series focuses on the primary grades; utilizes primary source literature from Japan;…

  20. Edited Excerpts from a Smithsonian Seminar Series--Part 3: The Humanities and Social Sciences.

    ERIC Educational Resources Information Center

    Borden, Carla M., Ed.; And Others

    1992-01-01

    The third article in a series of excerpts from seminars sponsored by the Smithsonian Institution on knowledge collaboration focuses on the humanities and social sciences. Reasons for the relatively greater frequency of collaborative research in the natural sciences are examined, and examples of collaborative projects in the humanities and social…

  1. NASPE Developed Informational Products and Applications. Article #4 in a 4-Part Series

    ERIC Educational Resources Information Center

    Fisette, Jennifer L.; Placek, Judith H.; Avery, Marybell; Dyson, Ben; Fox, Connie; Franck, Marian; Graber, Kim; Rink, Judith; Zhu, Weimo

    2009-01-01

    This is the fourth and final article in the "PE Metrics" series that focuses on assessing the National Standards for Physical Education (NASPE) for Standard 1. The first article focused on assessment of student learning. The second described formative and summative assessments and provided considerations on how to implement assessment within…

  2. Accounting Issues: An Essay Series Part IX--Statement of Cash Flows

    ERIC Educational Resources Information Center

    Laux, Judy

    2009-01-01

    This essay series, beginning with Laux [2007a], defends the proposition that eliminating the theoretical chapter from the principles level accounting course has weakened the introduction for students new to this subject, perhaps resulting in some adverse selection for the accounting profession. As a remedy, it offers concise theoretical articles…

  3. Edited Excerpts from a Smithsonian Seminar Series--Part 3: The Humanities and Social Sciences.

    ERIC Educational Resources Information Center

    Borden, Carla M., Ed.; And Others

    1992-01-01

    The third article in a series of excerpts from seminars sponsored by the Smithsonian Institution on knowledge collaboration focuses on the humanities and social sciences. Reasons for the relatively greater frequency of collaborative research in the natural sciences are examined, and examples of collaborative projects in the humanities and social…

  4. Mounting Pressures on Planet Earth. A Four-Part Bicentennial Symposium Series.

    ERIC Educational Resources Information Center

    Anderton, David A., Ed.

    Detailed are the proceedings of the 1976 Bicentennial Symposium Series held under the general title of Mounting Pressures on Planet Earth. This event, co-sponsored by the Maryland State Department of Education and the NASA Goddard Space Flight Center, brought together researchers and educators to discuss solutions to the Earth's problems. The…

  5. Part-Time Occupational Faculty: A Contribution to Excellence. Information Series No. 300.

    ERIC Educational Resources Information Center

    Parsons, Michael H.

    Part-time faculty are essential to the accomplishment of the mission of postsecondary occupational education institutions. A commitment to excellence requires a comprehensive, systematic design for part-time faculty recruitment, development, assessment, and integration into the institution's delivery system. Careful attention to recruitment…

  6. 40 CFR Table W - 6 of Subpart W of Part 98-Default Methane Emission Factors for LNG Import and Export Equipment

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Methane Emission Factors for LNG Import and Export Equipment W Table W Protection of Environment...—Default Methane Emission Factors for LNG Import and Export Equipment LNG import and export equipment Emission factor (scf/hour/component) Leaker Emission Factors—LNG Terminals Components, LNG Service Valve...

  7. 40 CFR Table W - 6 of Subpart W of Part 98-Default Methane Emission Factors for LNG Import and Export Equipment

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Methane Emission Factors for LNG Import and Export Equipment W Table W Protection of Environment...—Default Methane Emission Factors for LNG Import and Export Equipment LNG import and export equipment Emission factor (scf/hour/component) Leaker Emission Factors—LNG Terminals Components, LNG Service Valve...

  8. Optimization of Series Expressions. Part 2. Overview of the Theory and Implementation

    DTIC Science & Technology

    1989-12-01

    collect-sum (choose-if #’ oddp firstS)) 9 Figure 4.1: Illustration of the Lisp implementation of unoptimized series. 20 A Common Lisp Implementation the...one at a time as needed. (catenate (make-series I (+ 2 2)) #Z(7 8)) =, Z(i 4 7 8) (collect-first (choose-if *’ oddp #Z(8 -7 6 -1))) = -7 (subseries...34) " ") = #Z(" " "fee" "fi" "fo") (choose #Z(T nil T) #Z(1 2 3)) =: #Z(1 3) (choose Z(nil 3 4 nil)) =* #Z(3 4) (positions (map-fn #’ oddp #Z(1 2 3 5 6 8

  9. Design of a series of bicyclic HIV-1 integrase inhibitors. Part 2: azoles: effective metal chelators.

    PubMed

    Le, Giang; Vandegraaff, Nick; Rhodes, David I; Jones, Eric D; Coates, Jonathan A V; Thienthong, Neeranat; Winfield, Lisa J; Lu, Long; Li, Xinming; Yu, Changjiang; Feng, Xiao; Deadman, John J

    2010-10-01

    Synthesis of a diverse set of azoles and their utilizations as an amide isostere in the design of HIV integrase inhibitors is described. The Letter identified thiazole, oxazole, and imidazole as the most promising heterocycles. Initial SAR studies indicated that these novel series of integrase inhibitors are amenable to lead optimization. Several compounds with low nanomolar inhibitory potency are reported. Copyright © 2010 Elsevier Ltd. All rights reserved.

  10. Breaking methane

    PubMed Central

    Rosenzweig, Amy C.

    2015-01-01

    The most powerful oxidant found in nature is compound Q, an enzymatic intermediate that oxidizes methane. New spectroscopic data have resolved the long-running controversy about Q’s chemical structure. PMID:25607367

  11. Global Methane Biogeochemistry

    NASA Astrophysics Data System (ADS)

    Reeburgh, W. S.

    2003-12-01

    Methane (CH4) has been studied as an atmospheric constituent for over 200 years. A 1776 letter from Alessandro Volta to Father Campi described the first experiments on flammable "air" released by shallow sediments in Lake Maggiore (Wolfe, 1996; King, 1992). The first quantitative measurements of CH4, both involving combustion and gravimetric determination of trapped oxidation products, were reported in French by Boussingault and Boussingault, 1864 and Gautier (1901), who reported CH4 concentrations of 10 ppmv and 0.28 ppmv (seashore) and 95 ppmv (Paris), respectively. The first modern measurements of atmospheric CH4 were the infrared absorption measurements of Migeotte (1948), who estimated an atmospheric concentration of 2.0 ppmv. Development of gas chromatography and the flame ionization detector in the 1950s led to observations of vertical CH4 distributions in the troposphere and stratosphere, and to establishment of time-series sampling programs in the late 1970s. Results from these sampling programs led to suggestions that the concentration of CH4, as that of CO2, was increasing in the atmosphere. The possible role of CH4 as a greenhouse gas stimulated further research on CH4 sources and sinks. Methane has also been of interest to microbiologists, but findings from microbiology have entered the larger context of the global CH4 budget only recently.Methane is the most abundant hydrocarbon in the atmosphere. It plays important roles in atmospheric chemistry and the radiative balance of the Earth. Stratospheric oxidation of CH4 provides a means of introducing water vapor above the tropopause. Methane reacts with atomic chlorine in the stratosphere, forming HCl, a reservoir species for chlorine. Some 90% of the CH4 entering the atmosphere is oxidized through reactions initiated by the OH radical. These reactions are discussed in more detail by Wofsy (1976) and Cicerone and Oremland (1988), and are important in controlling the oxidation state of the atmosphere

  12. Synchronizable Series Expressions. Part 1. User’s Manual for the OSS Macro Package.

    DTIC Science & Technology

    1987-11-01

    programmers can obtain the advantages of expressing computations as series without incurring any * run-time overhead. %o X ,w A2.. "a 1. All You Need...To Know to Get Started "T [his first section describes everything you need to know to start using the oss macro package. It then presents a detailed...2 -2 3)) 3)) (Rsum (TmapF #’(lambda ( x ) (expt (abs x ) 3)) * (Evector #(2 -2 3)) 43 * Creating OSS variables. V he oSS Iiacro pa~ kage provides two

  13. Options in Education: Program No. 88. Sex and Sexism in Education, Part II. Transcripts of a Weekly Series Broadcast by Member Stations of National Public Radio.

    ERIC Educational Resources Information Center

    National Public Radio, Washington, DC.

    This booklet is a transcription of a program from the radio series, "Options in Education." It is part 2 of a two-part series dealing with sexism in education. It deals with sex discrimination in various aspects of public education, including textbooks, teacher promotion, sports programs and children's literature. There is also a…

  14. An Alternative Approach to Atopic Dermatitis: Part I—Case-Series Presentation

    PubMed Central

    2004-01-01

    Atopic dermatitis (AD) is a complex disease of obscure pathogenesis. A substantial portion of AD patients treated with conventional therapy become intractable after several cycles of recurrence. Over the last 20 years we have developed an alternative approach to treat many of these patients by diet and Kampo herbal medicine. However, as our approach is highly individualized and the Kampo formulae sometimes complicated, it is not easy to provide evidence to establish usefulness of this approach. In this Review, to demonstrate the effectiveness of the method of individualized Kampo therapy, results are presented for a series of patients who had failed with conventional therapy but were treated afterwards in our institution. Based on these data, we contend that there exist a definite subgroup of AD patients in whom conventional therapy fails, but the ‘Diet and Kampo’ approach succeeds, to heal. Therefore, this approach should be considered seriously as a second-line treatment for AD patients. In the Discussion, we review the evidential status of the current conventional strategies for AD treatment in general, and then specifically discuss the possibility of integrating Kampo regimens into it, taking our case-series presented here as evidential basis. We emphasize that Kampo therapy for AD is more ‘art’ than technology, for which expertise is an essential pre-requisite. PMID:15257326

  15. Progress report on LLTR Series II Test A-2 (Part 1). [LMFBR

    SciTech Connect

    Freede, W.J.; Neely, H.H.

    1980-01-01

    This document contains a complete set of valid and final digital and analog data plots for LLTR Series II, Test A-2. Included is an Accuracy Statement regarding this data as required by Revision 0 of the GE Test Request, Specification No. 23A2062. The Series II, Sodium-Water Reaction Test A-2 was performed in the Large Leak Test Rig (LLTR) at the Energy Technology Engineering Center (ETEC). This was the third of three planned double-edged guillotine (DEG) rupture tests of a single tube which will be followed by a number of small leak tests. The test article is the LLTI which is a full-size diameter internals, shortened in length and prototypic of the CRBR steam generator. It is installed in the Large Leak Test Vessel (LLTV). The overall test program was formulated by General Electric (GE) as Test Requester to establish steam generator design and to verify analytical models/codes to estimate the effect of large leak accidents in an LMFBR demonstration plant steam generator and system.

  16. The skaergaard layered series. Part IV. reaction-transport simulations of foundered blocks.

    SciTech Connect

    Sonnenthal, Eric L.; McBirney, Alexander R.

    1996-01-02

    During the middle stages of crystallization of the Skaergaard Layered Series large numbers of blocks became detached from the Upper Border Series and settled into the mush of crystals on the floor. It has been recognized for some time that these blocks now have compositions and textures that differ markedly from those of the units from which they came. They tend to be more plagioclase rich and seem to have lost mafic components to the surrounding gabbro. Numerical simulations coupling crystallization, melting, and heat and mass transfer for a multicomponent system show how the blocks reacted with the mush in which they were emplaced. Enhanced cooling and crystallization of a compositionally stratified mush adjacent to the blocks resulted in patterns of melt compositions similar to those of layering around the blocks. Volume changes during crystallization and melting induced convection of the interstitial melt leading to changes in the bulk compositions of the blocks and the surrounding mush. Inhomogeneities such as inclusions are likely to facilitate the onset of compositional convection in a chemically stratified solidification zone.

  17. Engineering Certification Program Self-Study Course, Construction Inspection - Part II. Engineering Management [Series].

    ERIC Educational Resources Information Center

    Owsley, Fran, Ed.

    This book is a part of a self-study sequence in an engineering certification program. This volume concerns inspection and quality control of concrete structures. Sections titles are Inspection and Quality Control of Concrete; General Guides for Concrete Work; Concrete Floor and Slab Construction; Concrete Formwork; Correct and Incorrect Methods of…

  18. Photophysical Study of a Series of Cyanines Part III. The Direct Photooxidation Reaction

    NASA Astrophysics Data System (ADS)

    Lepaja, Shukri; Strub, Henry; Lougnot, Daniel-Joseph

    1983-01-01

    The main degradative pathway of tricarbocyanine dyes in aerated solutions is demonstrated to be a photooxidation; using sensitization techniques and specific quenchers, this reaction is established to proceed via singlet oxygen for a part, and the site at which this species attacks the polymethinic skeleton is unambiguously determined. The major photoproduct is identified as being 1,3,3-trimethyl-2-indolinone.

  19. Attributes and National Behavior, Part 2: Modern International Relations Monograph Series. Patterns of Cooperation: Distance Theory.

    ERIC Educational Resources Information Center

    Vincent, Jack E.

    Part of a large scale research project to test various theories with regard to their ability to analyze international relations, this monograph presents data on the application of distance theory to patterns of cooperation among nations. Distance theory implies that international relations systems (nations, organizations, individuals, etc.) can be…

  20. DISTRIBUTIVE EDUCATION FOR ADULTS, GUIDE FOR PART-TIME INSTRUCTORS. DISTRIBUTIVE EDUCATION SERIES, NUMBER 21.

    ERIC Educational Resources Information Center

    KNEELAND, NATALIE; AND OTHERS

    MATERIAL IN THIS BULLETIN WAS COLLECTED FROM MANY STATES OPERATING SUCCESSFUL ADULT DISTRIBUTIVE EDUCATION PROGRAMS. IT WAS DEVELOPED BY A TRAINING CONSULTANT WITH THE ASSISTANCE OF PROGRAM SPECIALISTS FOR DISTRIBUTIVE EDUCATION IN THE U.S. OFFICE OF EDUCATION. SUGGESTIONS TO ASSIST THE PART-TIME INSTRUCTOR INCLUDE -- (1) LEARNING ABOUT THE JOB,…

  1. Engineering Certification Program Self-Study Course, Construction Inspection - Part II. Engineering Management [Series].

    ERIC Educational Resources Information Center

    Owsley, Fran, Ed.

    This book is a part of a self-study sequence in an engineering certification program. This volume concerns inspection and quality control of concrete structures. Sections titles are Inspection and Quality Control of Concrete; General Guides for Concrete Work; Concrete Floor and Slab Construction; Concrete Formwork; Correct and Incorrect Methods of…

  2. Modeling and Measurements of Atmospheric Methane at Four Corners, NM

    NASA Astrophysics Data System (ADS)

    Costigan, K. R.; Lindenmaier, R.; Dubey, M. K.

    2014-12-01

    Methane (CH4) fugitive emissions from fossil energy mining remain highly uncertain and scrutinized with the rapid expansion in domestic production by hydraulic fracturing. Top down observational studies of reported bottom up inventories are limited, but the latter may be biased low. We focus on the Four Corners region of the Southwestern United States, a region with extensive coal bed methane production, to verify its current emissions. At our site we measured methane over a range of scales using ground-based, in-situ instruments and a Fourier Transform Spectrometer (FTS), which is part of the Total Carbon Column Observing Network (TCCON). Measurements of CH4 produced much higher concentrations of methane in this rural area than previously expected. The diurnal variation and wind direction dependence in the CH4 concentrations suggest a source location tied to topographically induced winds and consistent with oil and gas production. This paper presents the results of WRF-Chem simulations that are performed to simulate methane concentrations in this region. Emissions from the Emissions Database for Global Atmospheric Research (EDGAR) indicate large CH4 emissions, associated with the gas production and distribution sector, in one 0.1 x 0.1 degree grid cell within the region and these emissions are employed in the simulations. A series of six simulations are run at two-month intervals during 2012. Each simulates a six-day time series to demonstrate the diurnal and seasonal characteristics of the methane concentrations that would be expected at the FTS location, from the sources reported in the EDGAR data set. The results of these simulations will be presented, along with the implications for interpretation of the FTS measurements. We will also interpret our FTS measurements of ethane (C2H6), which is emitted only from fossil fuel mining, to attribute leaks.

  3. Novel triterpene-derived hydrocarbons of the arborane/fernane series in sediments: Part II

    NASA Astrophysics Data System (ADS)

    Hauke, Verena; Graff, Roland; Wehrung, Patrick; Trendel, Jean M.; Albrecht, Pierre; Riva, Angelo; Hopfgartner, Gerard; Gülaçar, Fazil O.; Buchs, Armand; Eakin, Paul A.

    1992-09-01

    Two ring-B aromatized triterpenes related to the arborane/fernane series were isolated from an Italian Triassic black shale ( 4 and 7) and a French Jurassic laminated bituminous limestone (7). They were identified by MS and NMR spectroscopy. These compounds, 25-norferna-5,7,9-triene 7 (C 29) and 22,25,29,30-tetranor-18β-ferna-5,7,9-triene 4 (C 26), in the case of the Italian sediment, belong to a family which extends to at least C 32 as shown by GC-MS. The presence of higher homologs and ring-A methylated structures in the Italian Triassic shale is analogous with the hopane series, which together with carbon isotopic data obtained by gas chromatography-isotope ratio mass spectrometry (GC-IRMS), strongly support a bacterial origin for most of these compounds. This suggests that 4 and 7 may result from a yet unrecognized rearrangement of sedimentary hopenes which have subsequently undergone ring-B aromatization. As an alternative, the C 29 compound 7 could arise from C 30 precursors not necessarily of bacterial origin (fernenes?). This hypothesis would apply particularly to the case of the Jurassic limestone, which does not show any trace of 4 nor of compounds with an extended side chain or a methyl group on ring A. Related structures also bearing an isopropyl group could derive by microbiological transformations from the corresponding fernen-3β-ols or isoarborinol as can be deduced from the occurrence of ring-A degraded monoaromatic hydrocarbons 3 and 5.

  4. Part 2. Time-series study on air pollution and mortality in Delhi.

    PubMed

    Rajarathnam, Uma; Sehgal, Meena; Nairy, Subramanya; Patnayak, R C; Chhabra, Sunli Kumar; Kilnani; Ragavan, K V Santhosh

    2011-03-01

    Air pollution concentrations in most of the megacities in India exceed the air quality guidelines recommended by the World Health Organization and may adversely affect human health in these cities. Particulate matter (PM) is the pollutant of concern in many Indian cities, particularly in the capital city of Delhi, In recent years, several actions have been taken to address the growing air pollution problem in Delhi and other Indian cities; however, few studies have been designed to assess the health effects of air pollution in Indian cities. To bridge the gap in scientific knowledge and add evidence to the ongoing studies in other Asian cities, a retrospective time-series study on air pollution and mortality in Delhi was initiated under the HEI Public Health and Air Pollution in Asia (PAPA) program. The study used retrospective time-series data of air quality and of naturally-occurring deaths recorded in Delhi to identify changes in the daily all-natural-cause mortality rate that could be attributed to changes in air quality. The 3-year study period included the years 2002 through 2004. The methodology involved: (1) collecting data on ambient air quality for major pollutants from all monitoring stations in Delhi; (2) collecting meteorologic data (temperature, humidity, and visibility); (3) collecting daily mortality records from the Registrar of Births and Deaths; (4) statistically analyzing the data using the common protocol for Indian PAPA studies, which included city-specific modifications. The study findings showed that increased concentrations of PM with an aerodynamic diameter < or = 10 microg/m3 (PM10) and of nitrogen dioxide (NO2) were associated with increased all-natural-cause mortality. It was found that every 10-microg/m3 change in PM10 was associated with only a 0.15% increase in total all-natural-cause mortality. When NO2 alone was considered in the model, daily all-natural-cause mortality increased 0.84% for every 10-microg/m3 increase in NO2

  5. SeaWiFS technical report series. Volume 28: SeaWiFS algorithms, part 1

    NASA Technical Reports Server (NTRS)

    Hooker, Stanford B. (Editor); Firestone, Elaine R. (Editor); Acker, James G. (Editor); Mcclain, Charles R.; Arrigo, Kevin; Esaias, Wayne E.; Darzi, Michael; Patt, Frederick S.; Evans, Robert H.; Brown, James W.

    1995-01-01

    This document provides five brief reports that address several algorithm investigations sponsored by the Calibration and Validation Team (CVT) within the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Project. This volume, therefore, has been designated as the first in a series of algorithm volumes. Chapter 1 describes the initial suite of masks, used to prevent further processing of contaminated radiometric data, and flags, which are employed to mark data whose quality (due to a variety of factors) may be suspect. In addition to providing the mask and flag algorithms, this chapter also describes the initial strategy for their implementation. Chapter 2 evaluates various strategies for the detection of clouds and ice in high latitude (polar and sub-polar regions) using Coastal Zone Color Scanner (CZCS) data. Chapter 3 presents an algorithm designed for detecting and masking coccolithosphore blooms in the open ocean. Chapter 4 outlines a proposed scheme for correcting the out-of-band response when SeaWiFS is in orbit. Chapter 5 gives a detailed description of the algorithm designed to apply sensor calibration data during the processing of level-1b data.

  6. Production of rotational parts in small-series and computer-aided planning of its production engineering

    NASA Astrophysics Data System (ADS)

    Dudas, Illes; Berta, Miklos; Cser, Istvan

    1998-12-01

    Up-to-date manufacturing equipments of production of rotational parts in small series are lathe-centers and CNC grinding machines with high concentration of manufacturing operations. By the use of these machine tools it can be produced parts with requirements of increased accuracy and surface quality. In the lathe centers, which contain the manufacturing procedures of lathes using stationary tools and of drilling-milling machine tools using rotational tools, non-rotational surfaces of rotational parts can also be produced. The high concentration of manufacturing operations makes necessary the planning and programing of the measuring, monitoring and quality control into the technological process during manufacturing operation. In this way, taking into consideration the technological possibilities of lathe canters, the scope of computer aided technological planning duties significantly increases. It is trivial requirement to give only once the descriptions of the prefabricated parts and ready made parts. Starting taking into account these careful considerations we have been developing the planning system of technology of body of revolution on the base of GTIPROG/EC system which useful for programming of lathe centers. Out paper deals with the results of development and the occurring problems.

  7. Constraining Methane Flux Estimates Using Atmospheric Observations of Methane and 1^3C in Methane

    NASA Astrophysics Data System (ADS)

    Mikaloff Fletcher, S. E.; Tans, P. P.; Miller, J. B.; Bruhwiler, L. M.

    2002-12-01

    Understanding the budget of methane is crucial to predicting climate change and managing earth's carbon reservoirs. Methane is responsible for approximately 15% of the anthropogenic greenhouse forcing and has a large impact on the oxidative capacity of Earth's atmosphere due to its reaction with hydroxyl radical. At present, many of the sources and sinks of methane are poorly understood due in part to the large spatial and temporal variability of the methane flux. Model simulations of methane mixing ratios using most process-based source estimates typically over-predict the latitudinal gradient of atmospheric methane relative to the observations; however, the specific source processes responsible for this discrepancy have not been identified definitively. The aim of this work is to use the isotopic signatures of the sources to attribute these discrepancies to a source process or group of source processes and create global and regional budget estimates that are in agreement with both the atmospheric observations of methane and 1^3C in methane. To this end, observations of isotopic ratios of 1^3C in methane and isotopic signatures of methane source processes are used in conjunction with an inverse model of the methane budget. Inverse modeling is a top-down approach which uses observations of trace gases in the atmosphere, an estimate of the spatial pattern of trace gas fluxes, and a model of atmospheric transport to estimate the sources and sinks. The atmospheric transport was represented by the TM3 three-dimensional transport model. The GLOBALVIEW 2001 methane observations were used along with flask measurements of 1^3C in methane at six of the CMDL-NOAA stations by INSTAAR. Initial results imply interesting differences from previous methane budget estimates. For example, the 1^3C isotope observations in methane call for an increase in southern hemisphere sources with a bacterial isotopic signature such as wetlands, rice paddies, termites, and ruminant animals. The

  8. Methanation of CO and CO/sub 2/ for heat production

    SciTech Connect

    Arcilla, N.T.; Plumlee, D.E.

    1981-01-01

    This study explores workable CO and CO/sub 2/ methanation systems for process heat as part of a Thermo-Chemical Heat Pipe (TCHP) based on methane reforming. Tested methanator designs and methanation catalyst materials were reviewed to identify those suitable in high temperature, high pressure methanation. 7 refs.

  9. Diseases associated with hidranitis suppurativa: part 2 of a series on hidradenitis.

    PubMed

    Scheinfeld, Noah

    2013-06-15

    Hidradenitis suppurativa (HS), a pathologic follicular disease, impacts patients' lives profoundly and usually occurs in isolation. The diseases with the strongest association are obesity, depression, and pain. HS is associated with many diseases including acne conglobata (AC), dissecting cellulitis, pilonidal cysts, and obesity. Pyoderma fistulans sinifica (fox den disease) appears to be the same entity as Hurley Stage 2 of 3 HS. The rate of acne vulgaris in HS patients mirrors unaffected controls. The most common, albeit still uncommon, association is with seronegative, haplotype unlinked arthritis (most importantly B27), in particular spondolyarthritis. Crohn disease and HS occur together at a rate that varies from 0.6% to 38% in retrospective cases series. Ulcerative colitis occurred with HS in 14% of patients in one series. The next most common association is with pyoderma gangrenosum, but this association is likely under-reported. Synovitis-Acne-Pustulosis Hyperostosis-Osteitis (SAPHO) syndrome, which is rare, has more than 10 reports linking it to HS. Nine case reports have linked Dowling-Degos disease (DDD) to HS and two reports related HS to Fox-Fordyce disease (FF), but because both occur in the axilla this might be a mere coincidence. HS is rarely associated with ophthalmic pathology. Specifically, more than 5 reports link it to Keratitis-Ichthyosis-Deafness syndrome (KID); greater than10 cases link it to interstitial keratitis and 2 cases are linked to Behçet's disease. The presence of proteinuria and acute nephritis link HS to the kidney, especially since and reports have documented resolution of HS after renal transplant. Florid steatocystoma multiplex, Sjogren Syndrome, and HS have been linked and their reports likely underestimate their coincidence because all these entities involve occlusion (albeit by different mechanisms). Three reports link HS and amyloid, but both share some common genetic underpinnings and thus the coincidence of these

  10. The WAIS Divide deep ice core WD2014 chronology - Part 1: Methane synchronization (68-31 ka BP) and the gas age-ice age difference

    NASA Astrophysics Data System (ADS)

    Buizert, C.; Cuffey, K. M.; Severinghaus, J. P.; Baggenstos, D.; Fudge, T. J.; Steig, E. J.; Markle, B. R.; Winstrup, M.; Rhodes, R. H.; Brook, E. J.; Sowers, T. A.; Clow, G. D.; Cheng, H.; Edwards, R. L.; Sigl, M.; McConnell, J. R.; Taylor, K. C.

    2015-02-01

    The West Antarctic Ice Sheet Divide (WAIS Divide, WD) ice core is a newly drilled, high-accumulation deep ice core that provides Antarctic climate records of the past ∼68 ka at unprecedented temporal resolution. The upper 2850 m (back to 31.2 ka BP) have been dated using annual-layer counting. Here we present a chronology for the deep part of the core (67.8-31.2 ka BP), which is based on stratigraphic matching to annual-layer-counted Greenland ice cores using globally well-mixed atmospheric methane. We calculate the WD gas age-ice age difference (Δage) using a combination of firn densification modeling, ice-flow modeling, and a data set of δ15N-N2, a proxy for past firn column thickness. The largest Δage at WD occurs during the Last Glacial Maximum, and is 525 ± 120 years. Internally consistent solutions can be found only when assuming little to no influence of impurity content on densification rates, contrary to a recently proposed hypothesis. We synchronize the WD chronology to a linearly scaled version of the layer-counted Greenland Ice Core Chronology (GICC05), which brings the age of Dansgaard-Oeschger (DO) events into agreement with the U/Th absolutely dated Hulu Cave speleothem record. The small Δage at WD provides valuable opportunities to investigate the timing of atmospheric greenhouse gas variations relative to Antarctic climate, as well as the interhemispheric phasing of the "bipolar seesaw".

  11. FACT SHEET: EPAS STRATEGY FOR REDUCING METHANE AND OZONE-FORMING POLLUTION FROM THE OIL AND NATURAL GAS INDUSTRY

    EPA Pesticide Factsheets

    January 14, 2015 -- As part of the Obama Administration's commitment to addressing climate change, the U.S. Environmental Protection Agency (EPA) has outlined a series of steps it plans to take to address methane and smog-forming VOC emissions from the oil

  12. Sample size calculation in clinical trials: part 13 of a series on evaluation of scientific publications.

    PubMed

    Röhrig, Bernd; du Prel, Jean-Baptist; Wachtlin, Daniel; Kwiecien, Robert; Blettner, Maria

    2010-08-01

    In this article, we discuss the purpose of sample size calculation in clinical trials, the need for it, and the methods by which it is accomplished. Study samples that are either too small or too large are unacceptable, for clinical, methodological, and ethical reasons. The physicians participating in clinical trials should be directly involved in sample size planning, because their expertise and knowledge of the literature are indispensable. We explain the process of sample size calculation on the basis of articles retrieved by a selective search of the international literature, as well as our own experience. We present a fictitious clinical trial in which two antihypertensive agents are to be compared to each other with a t-test and then show how the appropriate size of the study sample should be calculated. Next, we describe the general principles of sample size calculation that apply when any kind of statistical test is to be used. We give further illustrative examples and explain what types of expert medical knowledge and assumptions are needed to calculate the appropriate sample size for each. These generally depend on the particular statistical test that is to be performed. In any clinical trial, the sample size has to be planned on a justifiable, rational basis. The purpose of sample size calculation is to determine the optimal number of participants (patients) to be included in the trial. Sample size calculation requires the collaboration of experienced biostatisticians and physician-researchers: expert medical knowledge is an essential part of it.

  13. Methane Painting

    NASA Image and Video Library

    2015-09-07

    Why does Saturn look like it's been painted with a dark brush in this infrared image, but Dione looks untouched? Perhaps an artist with very specific tastes in palettes? The answer is methane. This image was taken in a wavelength that is absorbed by methane. Dark areas seen here on Saturn are regions with thicker clouds, where light has to travel through more methane on its way into and back out of the atmosphere. Since Dione (698 miles or 1,123 kilometers across) doesn't have an atmosphere rich in methane the way Saturn does, it does not experience similar absorption -- the sunlight simply bounces off its icy surface. Shadows of the rings are seen cast onto the planet at lower right. This view looks toward Saturn from the unilluminated side of the rings, about 0.3 degrees below the ring plane. The image was taken with the Cassini spacecraft wide-angle camera on May 27, 2015 using a spectral filter which preferentially admits wavelengths of near-infrared light centered at 728 nanometers. http://photojournal.jpl.nasa.gov/catalog/PIA18336

  14. Landfill Methane

    USDA-ARS?s Scientific Manuscript database

    Landfill methane (CH4) accounts for approximately 1.3% (0.6 Gt) of global anthropogenic greenhouse gas emissions relative to total emissions from all sectors of about 49 Gt CO2-eq yr-1. For countries with a history of controlled landfilling, landfills can be one of the larger national sources of ant...

  15. Acute pediatric encephalitis neuroimaging: single-institution series as part of the California encephalitis project.

    PubMed

    Bykowski, Julie; Kruk, Peter; Gold, Jeffrey J; Glaser, Carol A; Sheriff, Heather; Crawford, John R

    2015-06-01

    Diagnosing pediatric encephalitis is challenging because of varied clinical presentation, nonspecific neuroimaging features, and rare confirmation of causality. We reviewed acute neuroimaging of children with clinically suspected encephalitis to identify findings that may correlate with etiology and length of stay. Imaging of 141 children with clinically suspected encephalitis as part of The California Encephalitis Project from 2005 to 2012 at a single institution was reviewed to compare the extent of neuroimaging abnormalities to patient age, gender, length of stay, and unknown, possible, or confirmed pathogen. Scan review was blinded and categorized by extent and distribution of abnormal findings. Abnormal findings were evident on 23% (22/94) of computed tomography and 50% (67/134) of magnetic resonance imaging studies in the acute setting. Twenty children with normal admission computed tomography had abnormal findings on magnetic resonance imaging performed within 2 days. Length of stay was significantly longer among children with abnormal acute magnetic resonance imaging (P < 0.001) and correlated with increased complexity (Spearman rho = 0.4, P < 0.001) categorized as: no imaging abnormality, meningeal enhancement and/or focal nonenhancing lesion, multifocal lesions, confluent lesions, and lesions plus diffusion restriction, hemorrhage, or hydrocephalus. There was no correlation between neuroimaging findings and an identifiable pathogen (P = 0.8). Abnormal magnetic resonance imaging findings are more common than abnormal computed tomography findings in pediatric encephalitis. Increasing complexity of magnetic resonance imaging findings correlated with disease severity as evidenced by longer length of stay, but were not specific for an identifiable pathogen using a standardized diagnostic encephalitis panel. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Adverse drug interactions in dental practice: interactions associated with vasoconstrictors. Part V of a series.

    PubMed

    Yagiela, J A

    1999-05-01

    Adrenergic vasoconstrictors are commonly used by dentists to enhance the pain-relieving action of local anesthetics and to control local bleeding. Although normally considered safe for these applications, vasoconstrictors can participate in drug interactions that potentially are harmful to patients. The faculty of a March 1998 symposium entitled "Adverse Drug Interactions in Dentistry: Separating the Myths From the Facts" extensively reviewed the literature on drug interactions. They then established a significance rating of alleged adverse drug interactions pertaining to dentistry, based on the quality of documentation and severity of effect. The author of this article focused on the adrenergic vasoconstrictors epinephrine and levonordefrin. Vasoconstrictor drug interactions involving tricyclic antidepressants, nonselective beta-adrenergic blocking drugs, certain general anesthetics and cocaine are well-documented in both humans and animals as having the potential for causing serious morbidity or death. Evidence for adverse interactions involving adrenergic neuronal blocking drugs, drugs with alpha-adrenergic blocking activity, local anesthetics and thyroid hormones is much less compelling, suggesting for the most part that clinically significant reactions may occur only when both the vasoconstrictor and the interacting drug are used in excessive doses. In the case of monoamine oxidase inhibitors, there is no credible evidence of a significant interaction with epinephrine or levonordefrin. Potentially serious adverse drug interactions involving adrenergic vasoconstrictors can occur in dental practice. In most circumstances, careful administration of small doses of vasoconstrictors and avoidance of gingival retraction cord containing epinephrine, coupled with monitoring of vita signs, will permit these drugs to be used with no risk or only minimally increased risk. Only in the case of cocaine intoxication must adrenergic vasoconstrictors be avoided completely. For

  17. A twenty year record of the 13C isotopic composition of methane from Cape Meares, Oregon (1978-1998)

    NASA Astrophysics Data System (ADS)

    Teama, D.; Rice, A. L.

    2009-12-01

    Methane is an important greenhouse gas, second only to carbon dioxide in its radiative forcing since the industrial revolution. Over this time, the concentration of methane has increased by ~150% , primarily as a result of anthropogenic practices such as fossil fuel production, rice cultivation, biomass burning and waste management. In 1980s and through the 1990s, direct measurements of atmospheric methane from several global monitoring networks showed that the growth rate slowed from its previous ~1% per year climb. The year 2000 was the first year to record a negative annual growth. However, interannual variations are large and there remains considerable uncertainty regarding future trends in the global burden of methane due, in part, to poorly quantified trends of sources and sinks. One tool to better understand trends in sources and sinks of methane is through the use of stable isotopes. By comparing trends in the13C/12C and D/H content of atmospheric methane in time series to the isotopic signatures of sources, we can potentially disentangle trends in methane sources and sinks. Here we report preliminary measurements of 13C/12C ratios in atmospheric methane from a rare historic archive of whole air collected at Cape Meares, Oregon (45.5 °N, 124 °W) during the period 1978-1998 as part of the global monitoring program at the Oregon Graduate Institute. This unique dataset is the only direct time series of methane isotopic composition in the northern hemisphere prior to the late 1980s and early 1990s. The measurements reveal an increasing trend in the δ13C of methane consistent with more recent time series and firn air results (0.2-0.4‰ year-1). The increase in δ 13C over this time reflects an increase in fossil (~ -40‰) and pyrogenic (~ -25‰) sources of methane, which are enriched relative to biogenic sources (~ -60‰), and the relaxation of δ13C associated with isotopic disequilibrium. We discuss the long term trend in δ13C, its shorter term

  18. Charters, Constitutions and By-Laws of the Indian Tribes of North America. Part XI: The Basin-Plateau Tribes. Occasional Publications in Anthropology, Ethnology Series, No. 12.

    ERIC Educational Resources Information Center

    Fay, George E., Comp.

    The Museum of Anthropology, University of Northern Colorado at Greeley, has assembled various American Indian tribal charters, constitutions, and by-laws to comprise a series of publications. The present volume, Part XI of the series, deals with the Indian tribes of Nevada: The Moapa Band of Paiute Indians, the Pyramid Lake Paiute Tribe, the…

  19. 32 CFR Appendix F to Part 197 - Procedures for Copying of Documents for the Foreign Relations of the United States Series

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 2 2012-07-01 2012-07-01 false Procedures for Copying of Documents for the Foreign Relations of the United States Series F Appendix F to Part 197 National Defense Department of...—Procedures for Copying of Documents for the Foreign Relations of the United States Series 1. The records...

  20. 32 CFR Appendix F to Part 197 - Procedures for Copying of Documents for the Foreign Relations of the United States Series

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 2 2014-07-01 2014-07-01 false Procedures for Copying of Documents for the Foreign Relations of the United States Series F Appendix F to Part 197 National Defense Department of...—Procedures for Copying of Documents for the Foreign Relations of the United States Series 1. The records...

  1. 32 CFR Appendix F to Part 197 - Procedures for Copying of Documents for the Foreign Relations of the United States Series

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 2 2013-07-01 2013-07-01 false Procedures for Copying of Documents for the Foreign Relations of the United States Series F Appendix F to Part 197 National Defense Department of...—Procedures for Copying of Documents for the Foreign Relations of the United States Series 1. The records...

  2. What we mean when we talk about MRD in myeloma. A review of current methods. Part 1 of a two-part series.

    PubMed

    Ely, Scott; Biran, Noa; Chari, Ajai

    2014-12-01

    Assessment of minimal residual disease (MRD) is becoming standard of care for potentially curable cancers, like some leukemias. For diseases not currently curable, like multiple myeloma (MM), the optimal methodology to assess MRD is much less clear, let alone the clinical significance. In this two-part series, we review each of these aspects of MRD in MM. In part 1, we review different methodologies available for MRD assessment, with an emphasis on multiparameter flow cytometry (MFC) and duplex immunohistochemistry. There is currently a strong push in the MM community for the use of MFC, based on studies demonstrating MRD negativity by MFC being associated with delayed time to relapse. After participating in a recent international meeting of leaders in the field, convened to discuss this topic, we review and assess the voiced opinions and published data. While great strides have been made toward the standardization of MFC for MRD, we review not only intrinsic biologic differences between MM and leukemia but also the technical challenges that follow from these differences, including the need for live cells, a difficult to characterize immunophenotype, and significant interlaboratory variability in MFC testing and interpretation.

  3. Holocene Concentrations of Methane in the Atmosphere are in Part Proportional to Concentrations of Sulfur Dioxide and Inversely Proportional to the Oxidizing Capacity of the Atmosphere

    NASA Astrophysics Data System (ADS)

    Ward, P. L.

    2008-12-01

    The atmosphere cleans itself by oxidizing pollutants. The primary oxidant is the hydroxyl radical (OH) formed by photodissociation of ozone in the near ultra-violet. Ozone and OH are in limited supply. Sulfur dioxide (SO2) absorbs near ultraviolet light limiting production of OH and reacts immediately with any available OH, forming sulfuric acid. Methane reacts more slowly with OH and will typically not be oxidized until there is little SO2. Thus a high concentration of methane indicates low oxidizing capacity. The rate at which SO2 is injected into the atmosphere controls oxidizing capacity and climate change in four ways: 1. Moderate rate: Large volcanic eruptions (VEI >=6) lower global temperatures for a few years when they are separated by years to decades so the oxidizing capacity of the atmosphere can fully recover. In 1991, Pinatubo volcano in the Philippines erupted 20 Mt SO2 and 491 Mt H2O, the largest volcanic eruption since 1912. The SO2 was oxidized primarily by OH to form a 99% pure aerosol of sulfuric acid and water at an elevation of 20-23 km. This aerosol reflected sunlight, lowering the world's temperature on average 0.4°C for three years. Ozone levels were reduced by 10%. Methane increased by 15 ppb for a year. The e-folding time for SO2 was 35 days. 2. High rate: When large eruptions occur once to several times per year, there is insufficient oxidizing capacity leading to increases in methane and other greenhouse gases and global warming. There were 15 times in the Holocene when large volcanoes erupted on average at least every year for 7 to 21 years. Man is now putting as much SO2 from burning fossil fuels into the atmosphere every year as one large volcano, causing current global warming. The two previous times were from 818-838 AD, the onset of the Medieval Warming Period, and from 180-143 BC, the onset of the Roman Warm Period. 3. Low rate: When there are no large eruptions for decades, the oxidizing capacity can catch up, cleaning the

  4. Alveolar soft part sarcoma of the oral and maxillofacial region: clinical analysis in a series of 18 patients.

    PubMed

    Wang, Hong-Wei; Qin, Xing-Jun; Yang, Wen-Jun; Xu, Li-Qun; Ji, Tong; Zhang, Chen-Ping

    2015-04-01

    To summarize the clinical features, diagnosis, treatment strategies, and prognosis of alveolar soft part sarcoma (ASPS) of the oral and maxillofacial region. We performed a retrospective study in a consecutive series of 18 patients with ASPS of the oral and maxillofacial region between 1995 and 2013. Demographic characteristics, tumor sizes, sites, tumor metastasis, diagnosis, treatments, and overall follow-ups were documented. The 18 patients were diagnosed pathologically with primary tumor developed on the tongue (10), the cheek (5), the pharynx (1), and the gingiva (2) with an average tumor size of 4 cm. At the latest follow-up, 1 patient with lung metastases survived for 23 months; 1 died 3 months after the confirmation of local recurrence and multiple pulmonary metastases; the rest of the patients were disease free and remained in good health. ASPS of the oral and maxillofacial region appears to have special clinical characteristics. Copyright © 2015. Published by Elsevier Inc.

  5. Characterization of ozone precursors in a regional background site of the Pearl River Delta by time series observation of non-methane hydrocarbons

    NASA Astrophysics Data System (ADS)

    Chang, C.; Wang, J.; Liu, S. C.; Lai, C.; Shao, M.; Zeng, L.; Zhang, Y.

    2009-12-01

    Continuous hourly measurements of C3-C12 non-methane hydrocarbons (NMHCs) were carried out in the period July 3 - 30, 2006 at a downwind site of Peal River Delta during the PRIDE-PRD2006 campaign. The measurements were intended to characterize the “residual composition” of ozone precursors through photochemical processing and to evaluate the photochemical relationship between oxidant (O3+NO2) and its precursors. An observation based method (OBM) of consumption concept is used to generate an ozone isopleth diagram that resembles the EKMA diagram, to examine the relationship of oxidant versus ozone precursors. A critical step in the method is to use observed concentrations of ethylbenzene and m,p-xylenes to estimate the degree of photochemical processing and amounts of photochemically consumed NOx and NMHCs by OH. The 3D OBM ozone isopleth diagram indicates that the observed oxidant level was sensitive to both of the consumed amounts of NMHCs and NOx. In addition, based on the 577 samples analyzed, toluene, benzene, isoprene, xylene and C3-C5 alkanes were found to be the most elevated species accounting for around 55% of the total measured NMHC abundance. After considering both the photochemical reactivities and mixing ratios of all the measured species, CO, isoprene, propene, xylene and toluene were calculated to have the highest ozone formation potentials (OFPs) accounting for 76.5% of total reactivity. Good correlation between NMHCs and 3-methylpentane, a proven good vehicular indicator, suggests vehicular emissions should be the major source for anthropogenic NMHCs. No correlation was found between isoprene and anthropogenic NMHCs, clearly supporting the existence of isoprene’s non-anthropogenic sources. Moreover, its diurnal pattern showed maximum mixing ratios around midday hours and minima at night, reflecting its biogenic properties which are both solar radiation and temperature dependent. Keywords: Age indicator; photochemical aging; NOx-control regime

  6. Traditional vs Modern: Role of Breed Type in Determining Enteric Methane Emissions from Cattle Grazing as Part of Contrasting Grassland-Based Systems

    PubMed Central

    Fraser, Mariecia D.; Fleming, Hannah R.; Moorby, Jon M.

    2014-01-01

    Ruminant livestock turn forages and poor-quality feeds into human edible products, but enteric methane (CH4) emissions from ruminants are a significant contributor to greenhouse gases (GHGs) and hence to climate change. Despite the predominance of pasture-based beef production systems in many parts of Europe there are little data available regarding enteric CH4 emissions from free-ranging grazing cattle. It is possible that differences in physiology or behaviour could influence comparative emissions intensities for traditional and modern breed types depending on the nutritional characteristics of the herbage grazed. This study investigated the role of breed type in influencing CH4 emissions from growing beef steers managed on contrasting grasslands typical of intensive (lowland) and extensive (upland) production systems. Using the SF6 dilution technique CH4 emissions were estimated for a modern, fast-growing crossbred (Limousin cross) and a smaller and hardier native breed (Welsh Black) when grazing lowland perennial ryegrass (high nutritional density, low sward heterogeneity) and semi-improved upland pasture (low/medium nutritional density, high sward heterogeneity). Live-weight gain was substantially lower for steers on the upland system compared to the lowland system (0.31 vs. 1.04 kg d−1; s.e.d. = 0.085 kg d−1; P<0.001), leading to significant differences in estimated dry matter intakes (8.0 vs. 11.1 kg DM d−1 for upland and lowland respectively; s.e.d. = 0.68 kg DM d−1; P<0.001). While emissions per unit feed intake were similar for the lowland and upland systems, CH4 emissions per unit of live-weight gain (LWG) were substantially higher when the steers grazed the poorer quality hill pasture (760 vs 214 g kg−1 LWG; s.e.d. = 133.5 g kg−1 LWG; P<0.001). Overall any effects of breed type were relatively small relative to the combined influence of pasture type and location. PMID:25259617

  7. Traditional vs modern: role of breed type in determining enteric methane emissions from cattle grazing as part of contrasting grassland-based systems.

    PubMed

    Fraser, Mariecia D; Fleming, Hannah R; Moorby, Jon M

    2014-01-01

    Ruminant livestock turn forages and poor-quality feeds into human edible products, but enteric methane (CH4) emissions from ruminants are a significant contributor to greenhouse gases (GHGs) and hence to climate change. Despite the predominance of pasture-based beef production systems in many parts of Europe there are little data available regarding enteric CH4 emissions from free-ranging grazing cattle. It is possible that differences in physiology or behaviour could influence comparative emissions intensities for traditional and modern breed types depending on the nutritional characteristics of the herbage grazed. This study investigated the role of breed type in influencing CH4 emissions from growing beef steers managed on contrasting grasslands typical of intensive (lowland) and extensive (upland) production systems. Using the SF6 dilution technique CH4 emissions were estimated for a modern, fast-growing crossbred (Limousin cross) and a smaller and hardier native breed (Welsh Black) when grazing lowland perennial ryegrass (high nutritional density, low sward heterogeneity) and semi-improved upland pasture (low/medium nutritional density, high sward heterogeneity). Live-weight gain was substantially lower for steers on the upland system compared to the lowland system (0.31 vs. 1.04 kg d-1; s.e.d. = 0.085 kg d-1; P<0.001), leading to significant differences in estimated dry matter intakes (8.0 vs. 11.1 kg DM d-1 for upland and lowland respectively; s.e.d. = 0.68 kg DM d-1; P<0.001). While emissions per unit feed intake were similar for the lowland and upland systems, CH4 emissions per unit of live-weight gain (LWG) were substantially higher when the steers grazed the poorer quality hill pasture (760 vs 214 g kg-1 LWG; s.e.d. = 133.5 g kg-1 LWG; P<0.001). Overall any effects of breed type were relatively small relative to the combined influence of pasture type and location.

  8. Coalbed Methane Outreach Program

    EPA Pesticide Factsheets

    Coalbed Methane Outreach Program, voluntary program seeking to reduce methane emissions from coal mining activities. CMOP promotes profitable recovery/use of coal mine methane (CMM), addressing barriers to using CMM instead of emitting it to atmosphere.

  9. METHANE: INDUSTRIAL SOURCES

    EPA Science Inventory

    The chapter provides qualitative information on the magnitude of industrial sources of methane and, where possible, provides information to allow the reader to quantify methane emissions. One difficulty in quantifying methane emissions from industry is the inconsistent treatment ...

  10. 32 CFR Appendix F to Part 197 - Procedures for Copying of Documents for the Foreign Relations of the United States Series

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 2 2011-07-01 2011-07-01 false Procedures for Copying of Documents for the Foreign Relations of the United States Series F Appendix F to Part 197 National Defense Department of... THE FILES OF THE OFFICE OF THE SECRETARY OF DEFENSE (OSD) Pt. 197, App. F Appendix F to Part...

  11. Optical constants of solid methane

    NASA Technical Reports Server (NTRS)

    Khare, Bishun N.; Thompson, W. R.; Sagan, C.; Arakawa, E. T.; Bruel, C.; Judish, J. P.; Khanna, R. K.; Pollack, J. B.

    1989-01-01

    Methane is the most abundant simple organic molecule in the outer solar system bodies. In addition to being a gaseous constituent of the atmospheres of the Jovian planets and Titan, it is present in the solid form as a constituent of icy surfaces such as those of Triton and Pluto, and as cloud condensate in the atmospheres of Titan, Uranus, and Neptune. It is expected in the liquid form as a constituent of the ocean of Titan. Cometary ices also contain solid methane. The optical constants for both solid and liquid phases of CH4 for a wide temperature range are needed for radiative transfer calculations, for studies of reflection from surfaces, and for modeling of emission in the far infrared and microwave regions. The astronomically important visual to near infrared measurements of solid methane optical constants are conspicuously absent from the literature. Preliminary results are presented of the optical constants of solid methane for the 0.4 to 2.6 micron region. K is reported for both the amorphous and the crystalline (annealed) states. Using the previously measured values of the real part of the refractive index, n, of liquid methane at 110 K n is computed for solid methane using the Lorentz-Lorentz relationship. Work is in progress to extend the measurements of optical constants n and k for liquid and solid to both shorter and longer wavelengths, eventually providing a complete optical constants database for condensed CH4.

  12. Mechanism and Kinetics of Methane Combustion, Part I: Thermal Rate Constants for Hydrogen-Abstraction Reaction of CH4 + O((3)P).

    PubMed

    Peng, Ya; Jiang, Zhong'an; Chen, Jushi

    2017-03-23

    The mechanism and kinetics of gas-phase hydrogen-abstraction by the O((3)P) from methane are investigated using ab initio calculations and dynamical methods. Not only are the electronic structure properties including the optimized geometries, relative energies, and vibrational frequencies of all the stationary points obtained from state-averaged complete active space self-consistent field calculations, but also the single-point energies for all points on the intrinsic reaction coordinate are evaluated using the internally contracted multireference configuration interaction approach with modified optimized cc-pCVDZ basis sets. Our calculations give a fairly accurate description of the regions around the (3)A″ transition state in the O((3)P) attacking a near-collinear H-CH3 direction with a barrier height of 12.53 kcal/mol, which is lower than those reported before. Subsequently, thermal rate constants for this hydrogen-abstraction are calculated using the canonical unified statistical theory method with the temperature ranging from 298 K to 1000 K. These calculated rate constants are in agreement with experiments. The present work reveals the reaction mechanism of hydrogen-abstraction by the O((3)P) from methane, and it is helpful for the understanding of methane combustion.

  13. Analysis of methane emissions from digested sludge.

    PubMed

    Schaum, C; Fundneider, T; Cornel, P

    2016-01-01

    The energetic use of sewage sludge is an important step in the generation of electricity and heat within a wastewater treatment plant (WWTP). For a holistic approach, methane emissions derived from anaerobic treatment have to be considered. Measurements show that methane dissolved in digested sludge can be analyzed via the vacuum salting out degassing method. At different WWTPs, dissolved methane was measured, showing a concentration range of approximately 7-37 mg CH4/L. The average concentration of dissolved methane in mesophilic digested sludge was approximately 29 mg CH4/L, which corresponds to an estimated yearly specific load of approximately 14-21 g CH4 per population equivalent. Comparisons between continuous and discontinuous digester feeding show that a temporary rise in the volume load causes increased concentrations of dissolved methane. Investigations using an industrial-scale digestion plant, consisting of three digestion tank operated in series, show comparable results.

  14. Coyote series data report LLNL/NWC 1981 LNG spill tests dispersion, vapor burn, and rapid-phase-transition. Volume 1. [7 experiments with liquefied natural gas, 2 with liquid methane, and one with liquid nitrogen

    SciTech Connect

    Goldwire, H.C. Jr.; Rodean, H.C.; Cederwall, R.T.; Kansa, E.J.; Koopman, R.P.; McClure, J.W.; McRae, T.G.; Morris, L.K.; Kamppinen, L.; Kiefer, R.D.

    1983-10-01

    The Coyote series of liquefied natural gas (LNG) spill experiments was performed at the Naval Weapons Center (NWC), China Lake, California, during the summer and fall of 1981. These tests were a joint effort of the Lawrence Livermore National Laboratory (LLNL) and the NWC and were sponsored by the US Department of Energy (DOE) and the Gas Research Institute. There were ten Coyote experiments, five primarily for the study of vapor dispersion and burning vapor clouds, and five for investigating the occurrence of rapid-phase-transition (RPT) explosions. Each of the last four of the five RPT tests consisted of a series of three spills. Seven experiments were with LNG, two were with liquid methane (LCH/sub 4/), and one was with liquid nitrogen (LN/sub 2/). Three arrays of instrumentation were deployed. An array of RPT diagnostic instruments was concentrated at the spill pond and was operated during all of the tests, vapor burn as well as RPT. The wind-field array was operated during the last nine experiments to define the wind direction and speed in the area upwind and downwind of the spill pond. The gas-dispersion array was deployed mostly downwind of the spill pond to measure gas concentration, humidity, temperature, ground heat flux, infrared (IR) radiation, and flame-front passage during three of the vapor dispersion and burn experiments (Coyotes 3, 5, and 6). High-speed color motion pictures were taken during every test, and IR imagery (side and overhead) was obtained during some vapor-burn experiments. Data was obtained by radiometers during Coyotes 3, 6, and 7. This report presents a comprehensive selection of the data obtained. It does not include any data analysis except that required to determine the test conditions and the reliability of the data. Data analysis is to be reported in other publications. 19 references, 76 figures, 13 tables.

  15. Methane: Fuel for the future

    SciTech Connect

    McGeer, P.; Durbin, E.

    1982-01-01

    In September of 1981, a world conference on alternative fuels entitled ''Methane - Fuel for the Future'' was held at Delta's River Inn in Vancouver, British Columbia. Approximately 500 registrants from over a dozen countries attended the two day meeting. The Western world has been adequately warned about the dangers of dependence on oil as an energy source and particularly as a transportation fuel. Over the past decade, the long-range prospect of a real depletion of the oil supply has been eclipsed by a series of artificial shortages precipitated by the Organization of Petroleum Exporting Countries (OPEC). Yet the remedies that have been employed to reduce this dependence - specifically energysaving measures and development of major new oil fields - provide only a temporary remission. This book points the way toward an effective solution to the oil problem, proposing methane as the most attractive choice for an alternative fuel. The book outlines the reasons for the superiority of methane to oil and synthetic fuels, citing availability, price, ease of distribution, and cleanliness and compatibility with current engines. In twenty-three articles the authors discuss the state-of-the-technology of using methane as a fuel for motor vehicles, the commercial aspects of methane as an alternative fuel, and the political problems associated with alternative fuel programs in seven countries.

  16. Coal Bed Methane Primer

    SciTech Connect

    Dan Arthur; Bruce Langhus; Jon Seekins

    2005-05-25

    During the second half of the 1990's Coal Bed Methane (CBM) production increased dramatically nationwide to represent a significant new source of income and natural gas for many independent and established producers. Matching these soaring production rates during this period was a heightened public awareness of environmental concerns. These concerns left unexplained and under-addressed have created a significant growth in public involvement generating literally thousands of unfocused project comments for various regional NEPA efforts resulting in the delayed development of public and fee lands. The accelerating interest in CBM development coupled to the growth in public involvement has prompted the conceptualization of this project for the development of a CBM Primer. The Primer is designed to serve as a summary document, which introduces and encapsulates information pertinent to the development of Coal Bed Methane (CBM), including focused discussions of coal deposits, methane as a natural formed gas, split mineral estates, development techniques, operational issues, producing methods, applicable regulatory frameworks, land and resource management, mitigation measures, preparation of project plans, data availability, Indian Trust issues and relevant environmental technologies. An important aspect of gaining access to federal, state, tribal, or fee lands involves education of a broad array of stakeholders, including land and mineral owners, regulators, conservationists, tribal governments, special interest groups, and numerous others that could be impacted by the development of coal bed methane. Perhaps the most crucial aspect of successfully developing CBM resources is stakeholder education. Currently, an inconsistent picture of CBM exists. There is a significant lack of understanding on the parts of nearly all stakeholders, including industry, government, special interest groups, and land owners. It is envisioned the Primer would being used by a variety of

  17. [Sources of Methane in the Boreal Region

    NASA Technical Reports Server (NTRS)

    1998-01-01

    In determining the global methane budget the sources of methane must be balanced with the sinks and atmospheric inventory. The approximate contribution of the different methane sources to the budget has been establish showing the major terrestrial inputs as rice, wetlands, bogs, fens, and tundra. Measurements and modeling of production in these sources suggest that temperature, water table height and saturation along with substratum composition are important in controlling methane production and emission. The isotopic budget of 13 C and D/H in methane can be used as a tool to clarify the global budget. This approach has achieved success at constraining the inputs. Studies using the isotopic approach place constraints on global methane production from different sources. Also, the relation between the two biogenic production pathways, acetate fermentation and CO2 reduction, and the effect of substratum composition can be made using isotope measurements shows the relation between the different biogenic, thermogenic and anthropogenic sources of methane as a function of the carbon and hydrogen isotope values for each source and the atmosphere, tropospheric composition. Methane emissions from ponds and fens are a significant source in the methane budget of the boreal region. An initial study in 1993 and 1994 on the isotopic composition of this methane source and the isotopic composition in relation to oxidation of methane at the sediment surface of the ponds or fen was conducted as part of our BOREAS project. The isotopic composition of methane emitted by saturated anoxic sediment is dependent on the sediment composition and geochemistry, but will be influenced by in situ oxidation, in part, a function of rooted plant activity. The influence of oxidation mediated by rooted plant activities on the isotopic composition of methane is not well known and will depend on the plant type, sediment temperature, and numerous other variables. Information on this isotopic composition

  18. Methane activation on supported transition metal catalysts

    NASA Astrophysics Data System (ADS)

    Carstens, Jason Ned

    At present, there is considerable interest in utilizing methane more efficiently as both a fuel source and as a starting material for the production of other, more valuable products. However, methane is a very stable molecule with strong C-H bonds that are difficult to break. This makes methane combustion or the formation of carbon-carbon bonds quite difficult. The present work focuses on the use of supported transition metal catalysts as a means of activating methane (i.e. breaking C-H bonds) at low temperatures to produce valuable products or energy. The conversion of methane into higher hydrocarbons. A low temperature (<750 K), direct process to effectively convert methane into higher hydrocarbons would be quite desirable. Such a process is thermodynamically feasible if the reaction is broken up into two separate steps. The first step is the adsorption of methane onto a transition metal catalyst at temperatures above about 600 K to produce a surface carbon species. The second step is a low temperature (<373 K) hydrogenation to convert the carbon species into higher hydrocarbons. T. Koerts et al. have pursued this approach by dissociatively absorbing methane onto silica supported transition metal catalysts at temperatures ranging between 573 K and 773 K. The result was a surface carbonaceous species and hydrogen. In the second step, the carbonaceous intermediates produced small alkanes upon hydrogenation around 373 K. A maximum yield to higher hydrocarbons of 13% was obtained on a ruthenium catalyst. The present study was conducted to further investigate the nature of the carbonaceous species reported by Koerts. Methane combustion. This investigation was conducted in an effort to better understand the mechanism of methane combustion on Pd catalysts. In the first part of this study, temperature programmed reduction (TPR) was used to investigate the oxidation and reduction dynamics of a 10 wt% Pd/ZrOsb2 catalyst used for methane combustion. TPR experiments indicate

  19. Coalbed methane resource potential and current prospects in Pennsylvania

    USGS Publications Warehouse

    Markowski, A.K.

    1998-01-01

    Coalbed methane gas content analyses from exploratory coal cores and existing data indicate that gas content generally increases with increasing depth and rank. The coal beds studied are from the Main Bituminous field of Pennsylvania (which currently contains 24 coalbed methane pools) and the Northern and Southern Anthracite coal fields. They range from the Middle Pennsylvanian Allegheny Group to the Late Pennsylvanian-Early Permian Dunkard Group. Previous US Bureau of Mines studies revealed gas contents from 0.4 to 13.8 cm3/g at depths of 99 to 432 m for the bituminous coal beds of the Allegheny Group. More recent core data from the Allegheny Group yielded gas contents from 2.2 to 8.9 cm3/g at depths from 167 to 387 m. In the Anthracite region of eastern Pennsylvania, the little data that are available show that gas content is anomalously high or low. Gas yields from test holes in eastern Pennsylvania are low with or without artificial stimulation mainly due to the lack of a good cleat system. Overall estimates of coalbed methane resources indicate there may be 1.7 Tm3 (61 Tcf) of gas-in-place contained in the Northern Appalachian coal basin. The amount of technically recoverable coalbed methane resources is projected by the US Geological Survey National Oil and Gas Resource Assessment Team [US Geological Survey National Oil and Gas Resource Assessment Team, 1996. 1995 National assessment of United States oil and gas resources-results, methodology, and supporting data, US Geological Survey Digital Data Series DDS-30, CD-ROM, Denver, CO, 80 pp.] and Lyons [Lyons, P.C., 1997. Central-northern Appalachian coalbed methane flow grows. Oil and Gas Journal 95 (27) 76-79] at 0.3 Tm3 (11.48 Tcf). This includes portions of Pennsylvania, Ohio, West Virginia, and a small part of Maryland. Consequently, a mapping investigation was conducted to evaluate the regional geology of the bituminous coal-bearing intervals in southwestern Pennsylvania and its influence on coalbed

  20. Early diagenesis in the sediments of the Congo deep-sea fan dominated by massive terrigenous deposits: Part III - Sulfate- and methane- based microbial processes

    NASA Astrophysics Data System (ADS)

    Pastor, L.; Toffin, L.; Decker, C.; Olu, K.; Cathalot, C.; Lesongeur, F.; Caprais, J.-C.; Bessette, S.; Brandily, C.; Taillefert, M.; Rabouille, C.

    2017-08-01

    Geochemical profiles (SO42-, H2S, CH4, δ13CH4) and phylogenetic diversity of Archaea and Bacteria from two oceanographic cruises dedicated to the lobes sediments of the Congo deep-sea fan are presented in this paper. In this area, organic-rich turbidites reach 5000 m and allow the establishment of patchy cold-seep-like habitats including microbial mats, reduced sediments, and vesicomyid bivalves assemblages. These bivalves live in endosymbiosis with sulfur-oxidizing bacteria and use sulfides to perform chemosynthesis. In these habitats, unlike classical abyssal sediments, anoxic processes are dominant. Total oxygen uptake fluxes and methane fluxes measured with benthic chambers are in the same range as those of active cold-seep environments, and oxygen is mainly used for reoxidation of reduced compounds, especially in bacterial mats and reduced sediments. High concentrations of methane and sulfate co-exist in the upper 20 cm of sediments, and evidence indicates that sulfate-reducing microorganisms and methanogens co-occur in the shallow layers of these sediments. Simultaneously, anaerobic oxidation of methane (AOM) with sulfate as the electron acceptor is evidenced by the presence of ANMEs (ANaerobic MEthanotroph). Dissolved sulfide produced through the reduction of sulfate is reoxidized through several pathways depending on the habitat. These pathways include vesicomyid bivalves uptake (adults or juveniles in the bacterial mats habitats), reoxidation by oxygen or iron phases within the reduced sediment, or reoxidation by microbial mats. Sulfide uptake rates by vesicomyids measured in sulfide-rich sea water (90±18 mmol S m-2 d-1) were similar to sulfide production rates obtained by modelling the sulfate profile with different bioirrigation constants, highlighting the major control of vesicomyids on sulfur cycle in their habitats.

  1. Zero methane-emitting peatlands: biogeochemical features and forecasting response to environmental change

    NASA Astrophysics Data System (ADS)

    Sirin, Andrey; Suvorov, Gennady; Glagolev, Mikhail; Kravchenko, Irina; Chistotin, Maxim; Bazhin, Nikolai

    2014-05-01

    Peatlands are one of the main sources of atmospheric CH4, a greenhouse gas responsible for a large part of current climate forcing. Existing estimates of methane flux from peatlands on a country, continental and global scale do not cover all variety of extremely diverse natural peatland ecosystems, their spatial uncertainties, and related to human impacts modifications. During last 2-3 decades numerous CH4flux measurements were conducted in northern peatlands, but many peatland types were not elaborated being suggested as unessential or even 'zero' source of methane to the atmosphere. Among them are widespread forested dwarf-shrub sphagnum peatbogs, frozen flat palsa mires, etc., as well as considered 'dry' peatlands drained and utilized for peat extraction, agriculture and forestry. Methane fluxes were measured at key peatland taiga test-plots of Central part of European Russia and taiga and tundra-forest zones of West Siberia purposely to examine periods of different level of humidity. The water level (WL) position switching from methane emission to uptake was elucidated for pine-dwarf-shrub-sphagnum ecotopes: at 50 cm WL near-zero or negative methane fluxes were registered at 86% of measurements, at 40 cm WL - emission at 89%. Observations in Central European Russia cover different natural and drained peatland types. Drainage and management usually decreased CH4 emissions relative to pristine peatlands through drying of surface peats and simultaneous decrease the size of anoxic horizons, but the rise of WL switches to CH4 fluxes. Relation between methane flux and peat wetness was additionally tested by series of lab mesocosm experiments. Processes resulting in similar final zero methane emissions under conditions of drained and intact peatland could be different. Microbial communities, involved in methane cycle, have been significantly changed in drained peatlands. Methanogens in natural peatlands were almost exclusively composed of hydrogenotrophs, whereas both

  2. Methane biofiltration using autoclaved aerated concrete as the carrier material.

    PubMed

    Ganendra, Giovanni; Mercado-Garcia, Daniel; Hernandez-Sanabria, Emma; Boeckx, Pascal; Ho, Adrian; Boon, Nico

    2015-09-01

    The methane removal capacity of mixed methane-oxidizing bacteria (MOB) culture in a biofilter setup using autoclaved aerated concrete (AAC) as a highly porous carrier material was tested. Batch experiment was performed to optimize MOB immobilization on AAC specimens where optimum methane removal was obtained when calcium chloride was not added during bacterial inoculation step and 10-mm-thick AAC specimens were used. The immobilized MOB could remove methane at low concentration (~1000 ppmv) in a biofilter setup for 127 days at average removal efficiency (RE) of 28.7 %. Unlike a plug flow reactor, increasing the total volume of the filter by adding a biofilter in series did not result in higher total RE. MOB also exhibited a higher abundance at the bottom of the filter, in proximity with the methane gas inlet where a high methane concentration was found. Overall, an efficient methane biofilter performance could be obtained using AAC as the carrier material.

  3. Dedos de Luna. Children's Literature in Spanish: Bilingual Edition. Guia para maestros en espanol e ingles. Elementary Literature Series, Part II.

    ERIC Educational Resources Information Center

    Walker, Dana; Huerta, Mario

    This curriculum unit is designed to give primary school students foreign language experiences and also to support the cultural literacy strand of the California State History-Social Science Framework. The unit is part of an elementary literature series which utilizes quality primary source literature from various world regions and countries and…

  4. Charters, Constitutions and By-Laws of the Indian Tribes of North America. Part IIa: The Northern Plains. Occasional Publications in Anthropology, Ethnology Series, No. 3.

    ERIC Educational Resources Information Center

    Fay, George E., Comp.

    Part IIa of a series of publications consisting of American Indian tribal governmental documents, this volume contains charters, constitutions, and by-laws of Indian tribes in the Northern Plains (Montana and North Dakota). Documents are presented relative to the Assiniboine and Sioux Tribes of the Fort Peck Reservation, the Blackfeet Tribe of the…

  5. Charters, Constitutions and By-Laws of the Indian Tribes of North America; Part IV: The Southwest (Navajo--Zuni). Occasional Publications in Anthropology Ethnology Series No. 5.

    ERIC Educational Resources Information Center

    Fay, George E., Comp.

    Part IV of a series of publications consisting of American Indian tribal governmental documents, this volume includes charters, constitutions, articles of association, and by-laws of Indian tribes of New Mexico and Arizona. Documents are included relative to the Navajo Tribe of Arizona and New Mexico; the Eastern Navajo Council--New Mexico; the…

  6. Dedos de Luna. Children's Literature in Spanish: Bilingual Edition. Guia para maestros en espanol e ingles. Elementary Literature Series, Part II.

    ERIC Educational Resources Information Center

    Walker, Dana; Huerta, Mario

    This curriculum unit is designed to give primary school students foreign language experiences and also to support the cultural literacy strand of the California State History-Social Science Framework. The unit is part of an elementary literature series which utilizes quality primary source literature from various world regions and countries and…

  7. Methane mapping and its seasonal cycle in the atmosphere of Western Siberia as observed by IASI

    NASA Astrophysics Data System (ADS)

    Khamatnurova, Marina; Gribanov, Konstantin; Zadvornykh, Ilya; Rokotyan, Nikita; Zakharov, Vyacheslav

    2014-05-01

    Western Siberia is wide area covered with pristine peatlands which play important role in global carbon balance. Large areas of arctic and subarctic wetlands are vulnerable to climate change and industrial activity on oil, natural gas mining together with their transportation. These areas can have important feedback mechanisms in global warming, due to their large carbon stocks and the presence of permafrost. This study presents iterative regularization methods, software tool and some results on CH4 content retrieval from Infrared Atmospheric Sounding Interferometer (IASI/MetOp series) spectra measured over Western Siberia. Dense coverage of IASI measurements can be used to map sink and source regions on the territory of target region. Because of pure statistics of direct vertical profile measurements and low signal to noise ratio for northern part of target region, only most stable methods of methane content retrieval are required. We used iteratively regularized Gauss-Newton and Levenberg-Marquardt methods without using a priory covariance matrices for methane vertical profiles. Some examples of interatively calculated averaging kernels for both methods are represented. Spatial distribution methane columnar value maps, seasonal variations for whole target region are represented. Comparison of ground-based FTIR measurements of methane in atmosphere with obtained IASI-CH4 over Kourovka site is presented. Comparison of GOSAT standard products for methane and our retrieval results are presented and discussed.

  8. Study on synchronous detection method of methane and ethane with laser absorption spectroscopy technology

    NASA Astrophysics Data System (ADS)

    He, Ying; Zhang, Yu-jun; You, Kun; Gao, Yan-wei; Chen, Chen; Liu, Jian-guo; Liu, Wen-qing

    2016-10-01

    The main ingredient of mash gas is alkenes, and methane is the most parts of mash gas and ethane is a small portion of it. Fast, accurate, real-time measurement of methane and ethane concentration is an important task for preventing coal mining disaster. In this research, a monitoring system with tunable diode laser absorption spectroscopy (TDLAS) technology has been set up for simultaneous measurement of methane and ethane, and a DFB laser at wavelength of 1.653μm was used as the laser source. The absorption spectroscopy information of methane and ethane, especially the characteristic of the spectrum peak positions and relative intensity were determined by available spectral structures from previous study and available database. Then, the concentration inversion algorithm method based on the spectral resolution and feature extraction was designed for methane and ethane synchronous detection. At last, the continuously experimental results obtained by different concentration of methane and ethane sample gases with the multiple reflection cell and the standard distribution system. In this experiment, the standard distribution system made with the standard gas and two high precision mass flow meters of D07 Sevenstar series whose flow velocity is 1l/min and 5l/min respectively. When the multiple reflection cell work stably, the biggest detection error of methane concentration inversion was 3.7%, and the biggest detection error of ethane was 4.8%. So it is verified that this concentration inversion algorithm works stably and reliably. Thus, this technology could realize the real-time, fast and continuous measurement requirement of mash gas and it will provide the effective technical support to coal mining production in safety for our country.

  9. Contribution of oil and natural gas production to renewed increase in atmospheric methane (2007-2014): top-down estimate from ethane and methane column observations

    NASA Astrophysics Data System (ADS)

    Hausmann, Petra; Sussmann, Ralf; Smale, Dan

    2016-03-01

    Harmonized time series of column-averaged mole fractions of atmospheric methane and ethane over the period 1999-2014 are derived from solar Fourier transform infrared (FTIR) measurements at the Zugspitze summit (47° N, 11° E; 2964 m a.s.l.) and at Lauder (45° S, 170° E; 370 m a.s.l.). Long-term trend analysis reveals a consistent renewed methane increase since 2007 of 6.2 [5.6, 6.9] ppb yr-1 (parts-per-billion per year) at the Zugspitze and 6.0 [5.3, 6.7] ppb yr-1 at Lauder (95 % confidence intervals). Several recent studies provide pieces of evidence that the renewed methane increase is most likely driven by two main factors: (i) increased methane emissions from tropical wetlands, followed by (ii) increased thermogenic methane emissions due to growing oil and natural gas production. Here, we quantify the magnitude of the second class of sources, using long-term measurements of atmospheric ethane as a tracer for thermogenic methane emissions. In 2007, after years of weak decline, the Zugspitze ethane time series shows the sudden onset of a significant positive trend (2.3 [1.8, 2.8] × 10-2 ppb yr-1 for 2007-2014), while a negative trend persists at Lauder after 2007 (-0.4 [-0.6, -0.1] × 10-2 ppb yr-1). Zugspitze methane and ethane time series are significantly correlated for the period 2007-2014 and can be assigned to thermogenic methane emissions with an ethane-to-methane ratio (EMR) of 12-19 %. We present optimized emission scenarios for 2007-2014 derived from an atmospheric two-box model. From our trend observations we infer a total ethane emission increase over the period 2007-2014 from oil and natural gas sources of 1-11 Tg yr-1 along with an overall methane emission increase of 24-45 Tg yr-1. Based on these results, the oil and natural gas emission contribution (C) to the renewed methane increase is deduced using three different emission scenarios with dedicated EMR ranges. Reference scenario 1 assumes an oil and gas emission combination with EMR = 7

  10. Comparison of Methods to Assess the Fate of Methane in a Landfill-Cover Soil

    NASA Astrophysics Data System (ADS)

    Gomez, K. E.; Schroth, M. H.; Eugster, W.; Niklaus, P.; Oester, P.; Zeyer, J.

    2008-12-01

    A substantial fraction of the greenhouse gas methane released into the atmosphere is produced in terrestrial environments such as wetlands, rice paddy fields, and landfills. However, the amount of methane that is emitted from these environments is often reduced by microbial methane oxidation, mediated by methanotrophic microorganisms. Methanotrophs are ubiquitous in soils and represent the largest biological sink for methane. We performed a series of field experiments in summer 2008 to compare several state-of- the-art methods to assess the fate of methane in a landfill-cover soil near Liestal (BL), Switzerland. Methods employed included eddy-covariance and field-chamber measurements to quantify net methane flux at the landfill surface. In addition, methane concentrations at the landfill surface were monitored using a portable methane detector. Methane fluxes within the cover soil were estimated from methane-concentration profiles in conjunction with radon measurements. Additionally, gas push-pull tests were employed for in-situ quantification of methane oxidation in the cover soil. Finally, methane stable-carbon-isotope measurements were conducted to corroborate methane oxidation in the cover soil. Preliminary results indicate that each method provides unique information, and when combined, the data provide detailed insight in the fate of methane in the cover soil. The investigated landfill-cover soil appears to be ordinarily a net sink for methane. However, it can quickly turn into a net source of methane under adverse meteorological conditions.

  11. Methane Plumes on Mars

    NASA Image and Video Library

    Spectrometer instruments attached to several telescopes detect plumes of methane emitted from Mars during its summer and spring seasons. High levels of methane are indicated by warmer colors. The m...

  12. Optical constants of solid methane

    NASA Technical Reports Server (NTRS)

    Khare, Bishun N.; Thompson, W. R.; Sagan, C.; Arakawa, E. T.; Bruel, C.; Judish, J. P.; Khanna, R. K.; Pollack, J. B.

    1990-01-01

    Methane is the most abundant simple organic molecule in the outer solar system bodies. In addition to being a gaseous constituent of the atmospheres of the Jovian planets and Titan, it is present in the solid form as a constituent of icy surfaces such as those of Triton and Pluto, and as cloud condensate in the atmospheres of Titan, Uranus, and Neptune. It is expected in the liquid form as a constituent of the ocean of Titan. Cometary ices also contain solid methane. The optical constants for both solid and liquid phases of CH4 for a wide temperature range are needed for radiative transfer calculations, for studies of reflection from surfaces, and for modeling of emission in the far infrared and microwave regions. The astronomically important visual to near infrared measurements of solid methane optical constants are conspicuously absent from the literature. Preliminary results are presented on the optical constants of solid methane for the 0.4 to 2.6 micrometer region. Deposition onto a substrate at 10 K produces glassy (semi-amorphous) material. Annealing this material at approximately 33 K for approximately 1 hour results in a crystalline material as seen by sharper, more structured bands and negligible background extinction due to scattering. The constant k is reported for both the amorphous and the crystalline (annealed) states. Typical values (at absorption maxima) are in the .001 to .0001 range. Below lambda = 1.1 micrometers the bands are too weak to be detected by transmission through the films less than or equal to 215 micrometers in thickness, employed in the studies to date. Using previously measured values of the real part of the refractive index, n, of liquid methane at 110 K, n is computed for solid methane using the Lorentz-Lorenz relationship. Work is in progress to extend the measurements of optical constants n and k for liquid and solid to both shorter and longer wavelengths, eventually providing a complete optical constants database for

  13. Potential methane reservoirs beneath Antarctica.

    PubMed

    Wadham, J L; Arndt, S; Tulaczyk, S; Stibal, M; Tranter, M; Telling, J; Lis, G P; Lawson, E; Ridgwell, A; Dubnick, A; Sharp, M J; Anesio, A M; Butler, C E H

    2012-08-30

    Once thought to be devoid of life, the ice-covered parts of Antarctica are now known to be a reservoir of metabolically active microbial cells and organic carbon. The potential for methanogenic archaea to support the degradation of organic carbon to methane beneath the ice, however, has not yet been evaluated. Large sedimentary basins containing marine sequences up to 14 kilometres thick and an estimated 21,000 petagrams (1 Pg equals 10(15) g) of organic carbon are buried beneath the Antarctic Ice Sheet. No data exist for rates of methanogenesis in sub-Antarctic marine sediments. Here we present experimental data from other subglacial environments that demonstrate the potential for overridden organic matter beneath glacial systems to produce methane. We also numerically simulate the accumulation of methane in Antarctic sedimentary basins using an established one-dimensional hydrate model and show that pressure/temperature conditions favour methane hydrate formation down to sediment depths of about 300 metres in West Antarctica and 700 metres in East Antarctica. Our results demonstrate the potential for methane hydrate accumulation in Antarctic sedimentary basins, where the total inventory depends on rates of organic carbon degradation and conditions at the ice-sheet bed. We calculate that the sub-Antarctic hydrate inventory could be of the same order of magnitude as that of recent estimates made for Arctic permafrost. Our findings suggest that the Antarctic Ice Sheet may be a neglected but important component of the global methane budget, with the potential to act as a positive feedback on climate warming during ice-sheet wastage.

  14. Heat pipe methanator

    DOEpatents

    Ranken, William A.; Kemme, Joseph E.

    1976-07-27

    A heat pipe methanator for converting coal gas to methane. Gravity return heat pipes are employed to remove the heat of reaction from the methanation promoting catalyst, transmitting a portion of this heat to an incoming gas pre-heat section and delivering the remainder to a steam generating heat exchanger.

  15. Oxygen-Methane Thruster

    NASA Technical Reports Server (NTRS)

    Pickens, Tim

    2012-01-01

    An oxygen-methane thruster was conceived with integrated igniter/injector capable of nominal operation on either gaseous or liquid propellants. The thruster was designed to develop 100 lbf (approximately 445 N) thrust at vacuum conditions and use oxygen and methane as propellants. This continued development included refining the design of the thruster to minimize part count and manufacturing difficulties/cost, refining the modeling tools and capabilities that support system design and analysis, demonstrating the performance of the igniter and full thruster assembly with both gaseous and liquid propellants, and acquiring data from this testing in order to verify the design and operational parameters of the thruster. Thruster testing was conducted with gaseous propellants used for the igniter and thruster. The thruster was demonstrated to work with all types of propellant conditions, and provided the desired performance. Both the thruster and igniter were tested, as well as gaseous propellants, and found to provide the desired performance using the various propellant conditions. The engine also served as an injector testbed for MSFC-designed refractory combustion chambers made of rhenium.

  16. The "Caring" Role in a Child Care Center. Staff Development Series, Military Child Care Project. Part II: Relating to Parents.

    ERIC Educational Resources Information Center

    Scavo, Marlene; And Others

    Material related to routine as well as sensitive aspects of parent/day care center relationships is presented in this training module, one of a series providing staff development information for programs operated for dependents of military personnel. The module offers a brief discussion of ways caregivers can help parents feel at ease about…

  17. The "Caring" Role in a Child Care Center. Staff Development Series, Military Child Care Project. Part I: Orientation.

    ERIC Educational Resources Information Center

    Scavo, Marlene; And Others

    One in a series written for caregivers or teachers in military child care centers, this staff development module provides brief discussions of aspects of child caregiving, describes related situations which beginning caregivers are likely to find difficult, offers alternate ways of responding to the difficulty, and provides feedback on caregivers'…

  18. Economic Stress and Suicide: Multilevel Analyses. Part 1: Aggregate Time-Series Analyses of Economic Stress and Suicide.

    ERIC Educational Resources Information Center

    Dooley, David; And Others

    1989-01-01

    Conducted two studies on economic stress and suicide on same population. First study replicated aggregate time-series work using monthly data for 1975-82 for Los Angeles, California. Results do not support contention that economic contraction has strong, widespread effect on suicide in general population. Findings suggest effect that regional…

  19. Innovations and Future Directions for Early Numeracy Curriculum-Based Measurement: Commentary on the Special Series, Part 2

    ERIC Educational Resources Information Center

    Methe, Scott A.

    2012-01-01

    The purpose of this extended commentary article is to frame the set of studies in the first of two issues and recommend areas of inquiry for future research. This special series issue features studies examining the technical qualities of formative assessment procedures that were developed to inform intervention. This article intends to emphasize…

  20. Structural and thermodiffractometric analysis of coordination polymers. Part I: tin derivatives of the Bim ligand [Bim = Bis(1-imidazolyl)methane]).

    PubMed

    Masciocchi, Norberto; Pettinari, Claudio; Alberti, Enrica; Pettinari, Riccardo; Nicola, Corrado Di; Albisetti, Alessandro Figini; Sironi, Angelo

    2007-12-10

    New polynuclear coordination species containing the ditopic bis(1-imidazolyl)methane (Bim) ligand have been prepared as microcrystalline powders and structurally characterized by ab initio X-ray powder diffraction methods. [Bim(Me2SnCl2)]n (1), [Bim(nBu2SnCl2)]n (3), [Bim(Ph2SnCl2)]n (4), [Bim(MeSnCl3)]n (5), and [Bim(PhSnCl3)]n (6) all contain 1D chains with octahedral tin atoms with trans N-Sn-N linkages (but 4, which displays a cis N-Sn-N linkage). Their thermodiffractometric analysis allowed the estimation of the linear thermal expansion coefficients and strain tensors derived there from. The potential-energy surface of the free Bim ligand (as defined by two torsional degrees of freedom about the two N-CH2 bonds), eventually controlling the length of the repeating unit (polymer elongation), has been estimated using molecular mechanics and correlated with experimental observations.

  1. Structural and thermodiffractometric analysis of coordination polymers. Part II: zinc and cadmium derivatives of the Bim ligand [Bim = bis(1-imidazolyl)methane].

    PubMed

    Masciocchi, Norberto; Pettinari, Claudio; Alberti, Enrica; Pettinari, Riccardo; Nicola, Corrado Di; Albisetti, Alessandro Figini; Sironi, Angelo

    2007-12-10

    New polynuclear coordination species containing the ditopic bis(1-imidazolyl)methane (Bim) ligand have been prepared as microcrystalline powders and structurally characterized by ab initio X-ray powder diffraction methods. [Zn(CH3COO)2(Bim)]n contains 1D chains with tetrahedral metal atoms bridged by Bim ligands; [CdBr2(Bim)]n shows a dense packing with hexacoordinated Cd(II) ions and mu-Br and mu-Bim bridges; at variance, the isomorphous [ZnCl2(Bim)]n and [ZnBr2(Bim)]n species contain cyclic dimers based on tetrahedral Zn(II) ions. Thermodiffractometric analysis allowed estimation of the linear thermal expansion coefficients and strain tensors derived there from. Bim-rich phases, with 2:1 ligand-to-metal ratio, were also isolated: ZnBr2(Bim)2(H2O)3 and [Cd(CH3COO)2(Bim)2]n containing cis and trans MN4O2 chromophores, respectively, show 1D polymers built upon M2Bim2 cycles, hinged on the metal ions. In all species the conformation of the Bim ligands is Cs (or nearly so), while in the few sparse reports of similar coordination polymers the alternative C2 one was preferentially observed.

  2. Part 1. A time-series study of ambient air pollution and daily mortality in Shanghai, China.

    PubMed

    Kan, Haidong; Chen, Bingheng; Zhao, Naiqing; London, Stephanie J; Song, Guixiang; Chen, Guohai; Zhang, Yunhui; Jiang, Lili

    2010-11-01

    Although the relation between outdoor air pollution and daily mortality has been examined in several Chinese cities, there are still a number of key scientific issues to be addressed concerning the health effects of air pollution in China. Given the changes over the past decade in concentrations and sources of air pollution (e.g., the change from one predominant source [coal combustion], which was typical of the twentieth century, to a mix of sources [coal combustion and motor-vehicle emissions]) and transition in China, it is worthwhile to investigate the acute effects of outdoor air pollution on mortality outcomes in the country. We conducted a time-series study to investigate the relation between outdoor air pollution and daily mortality in Shanghai using four years of daily data (2001-2004). This study is a part of the Public Health and Air Pollution in Asia (PAPA) program supported by the Health Effects Institute (HEI). We collected data on daily mortality, air pollution, and weather from the Shanghai Municipal Center of Disease Control and Prevention (SMCDCP), Shanghai Environmental Monitoring Center, and Shanghai Meteorologic Bureau. An independent auditing team assigned by HEI validated all the data. Our statistical analysis followed the Common Protocol of the PAPA program (found at the end of this volume). Briefly, a natural-spline model was used to analyze the mortality, air pollution, and covariate data. We first constructed the basic models for various mortality outcomes excluding variables for air pollution, and used the partial autocorrelation function of the residuals to guide the selection of degrees of freedom for time trend and lag days for the autoregression terms. Thereafter, we introduced the pollutant variables and analyzed their effects on mortality outcomes, including both mortality due to all natural (nonaccidental) causes and cause-specific mortality. We fitted single- and multipollutant models to assess the stability of the effects of the

  3. Part 4 of a 4-part series Miscellaneous Products: Trends and Alternatives in Deodorants, Antiperspirants, Sunblocks, Shaving Products, Powders, and Wipes

    PubMed Central

    Jacob, Sharon; Katta, Rajani; Nedorost, Susan; Warshaw, Erin; Zirwas, Matt; Selbo, Nicole

    2011-01-01

    Objective: To provide updated data on the usage of ingredients that are common potential contact allergens in several categories of topical products. To identify useful alternative products with few or no common contact allergens. Design: In November 2009, the full ingredient lists of 5,416 skin, hair, and cosmetic products marketed by the CVS pharmacy chain were copied from CVS.com into Microsoft Word format for analysis. Computer searches were made in Microsoft Word using search/replace and sorting functions to accurately identify the presence of specific allergens in each website product. Measurements: Percentages of American Contact Dermatitis Society core series allergens (and other common preservatives and sunblocks) were calculated. Results: The usage of American Contact Dermatitis Society core series allergens (and other preservatives and sunblocks) in various miscellaneous categories of topical products is reported. Conclusion: Data on allergens and alternatives for ancillary skin care products are not widely published. This article reviews some of the common potential allergens in antiperspirants, deodorants, shaving products, sunblocks, powders, and wipes. Suitable available alternative products for patients with contact allergy are listed. PMID:22010054

  4. Part 4 of a 4-part series Miscellaneous Products: Trends and Alternatives in Deodorants, Antiperspirants, Sunblocks, Shaving Products, Powders, and Wipes: Data from the American Contact Alternatives Group.

    PubMed

    Scheman, Andrew; Jacob, Sharon; Katta, Rajani; Nedorost, Susan; Warshaw, Erin; Zirwas, Matt; Selbo, Nicole

    2011-10-01

    To provide updated data on the usage of ingredients that are common potential contact allergens in several categories of topical products. To identify useful alternative products with few or no common contact allergens. In November 2009, the full ingredient lists of 5,416 skin, hair, and cosmetic products marketed by the CVS pharmacy chain were copied from CVS.com into Microsoft Word format for analysis. Computer searches were made in Microsoft Word using search/replace and sorting functions to accurately identify the presence of specific allergens in each website product. Percentages of American Contact Dermatitis Society core series allergens (and other common preservatives and sunblocks) were calculated. The usage of American Contact Dermatitis Society core series allergens (and other preservatives and sunblocks) in various miscellaneous categories of topical products is reported. Data on allergens and alternatives for ancillary skin care products are not widely published. This article reviews some of the common potential allergens in antiperspirants, deodorants, shaving products, sunblocks, powders, and wipes. Suitable available alternative products for patients with contact allergy are listed.

  5. Flexible Pedagogies: Part-Time Learners and Learning in Higher Education. Flexible Pedagogies: Preparing for the Future Series

    ERIC Educational Resources Information Center

    McLinden, Michael

    2013-01-01

    This publication focuses on national and international policy initiatives to develop a better understanding of part-time learners and the types of flexibility that may enhance their study especially pedagogically. As part of our five-strand research project "Flexible Pedagogies: preparing for the future" it: (1) highlights the challenges…

  6. Flexible Pedagogies: Part-Time Learners and Learning in Higher Education. Flexible Pedagogies: Preparing for the Future Series

    ERIC Educational Resources Information Center

    McLinden, Michael

    2013-01-01

    This publication focuses on national and international policy initiatives to develop a better understanding of part-time learners and the types of flexibility that may enhance their study especially pedagogically. As part of our five-strand research project "Flexible Pedagogies: preparing for the future" it: (1) highlights the challenges…

  7. Methane Measurements by NASA Curiosity in Mars Gale Crater

    NASA Image and Video Library

    2014-12-16

    This graphic shows tenfold spiking in the abundance of methane in the Martian atmosphere surrounding NASA Curiosity Mars rover, as detected by a series of measurements made with the Tunable Laser Spectrometer instrument in the rover laboratory suite.

  8. Homicide by methane gas.

    PubMed

    De-Giorgio, Fabio; Grassi, Vincenzo M; Vetrugno, Giuseppe; Rossi, Riccardo; Fucci, Nadia; d'Aloja, Ernesto; Pascali, Vincenzo L

    2012-09-10

    Methane is a suffocating gas, and "methane deaths" are largely the result of suffocation by gas-air displacement after accidental or deliberate exposure. Neither methane gas nor other suffocating gases are a common means of homicide, with the potential exception of the use of gas in chemical weapons or gas chambers. Here, we report the case of a 53-year-old woman who was killed by her husband with methane gas. The man had given his wife a dose of Lorazepam before setting up a hose that conveyed methane from the kitchen into the apartment's bedroom. The man subsequently faked his own suicide, which was later discovered.

  9. How pharmacogenomics (PG) are changing practice: implications for prescribers, their patients, and the healthcare system (PG series part I).

    PubMed

    Preskorn, Sheldon H; Hatt, Cassandra R

    2013-03-01

    This is the first column of a series discussing how advances in pharmacogenomic information (PGI) and molecular biology are leading to changes in the product labels of existing drugs and providing new targets for drug discovery. This column first introduces the concept of PGI and defines related terminology. The authors then discuss how new information on genetic variations in patient responses to drugs has led to revisions in the product labels of many already marketed drugs. Rapidly expanding PGI has also led to the development of new drugs with novel mechanisms of action. Such drug development has been especially common in oncology, with new agents being developed to target genetically specific forms of cancer. The authors review how genetically determined variations in the pharmacokinetics and pharmacodynamics of a drug in a specific patient can make that patient "sensitive" or "resistant" to the effects of that particular drug. This type of PGI is expanding the concept of "special populations" to include patients with genetically determined differences in pharmacokinetics and/or pharmacodynamics. The second column in this series will explain how increased knowledge of molecular pharmacology and PGI has resulted in the revision of product labels for drugs already on the market, using pimozide as an example. The third column in this series will deal with the discovery of new drugs with novel mechanisms of action, with a focus on oncology drugs. The last column in the series will discuss the need to make this knowledge readily accessible to clinicians at the time and point of therapeutic care.

  10. Methane Hydrates: Chapter 8

    USGS Publications Warehouse

    Boswell, Ray; Yamamoto, Koji; Lee, Sung-Rock; Collett, Timothy S.; Kumar, Pushpendra; Dallimore, Scott

    2008-01-01

    Gas hydrate is a solid, naturally occurring substance consisting predominantly of methane gas and water. Recent scientific drilling programs in Japan, Canada, the United States, Korea and India have demonstrated that gas hydrate occurs broadly and in a variety of forms in shallow sediments of the outer continental shelves and in Arctic regions. Field, laboratory and numerical modelling studies conducted to date indicate that gas can be extracted from gas hydrates with existing production technologies, particularly for those deposits in which the gas hydrate exists as pore-filling grains at high saturation in sand-rich reservoirs. A series of regional resource assessments indicate that substantial volumes of gas hydrate likely exist in sand-rich deposits. Recent field programs in Japan, Canada and in the United States have demonstrated the technical viability of methane extraction from gas-hydrate-bearing sand reservoirs and have investigated a range of potential production scenarios. At present, basic reservoir depressurisation shows the greatest promise and can be conducted using primarily standard industry equipment and procedures. Depressurisation is expected to be the foundation of future production systems; additional processes, such as thermal stimulation, mechanical stimulation and chemical injection, will likely also be integrated as dictated by local geological and other conditions. An innovative carbon dioxide and methane swapping technology is also being studied as a method to produce gas from select gas hydrate deposits. In addition, substantial additional volumes of gas hydrate have been found in dense arrays of grain-displacing veins and nodules in fine-grained, clay-dominated sediments; however, to date, no field tests, and very limited numerical modelling, have been conducted with regard to the production potential of such accumulations. Work remains to further refine: (1) the marine resource volumes within potential accumulations that can be

  11. An excess vessel in the posterior part of the human cerebral arterial circle (CAC): a case series.

    PubMed

    Vasović, Ljiljana; Trandafilović, Milena; Jovanović, Ivan; Antović, Aleksandra; Stojanović, Jovan; Zdravković, Miodrag; Milić, Miroslav

    2010-06-23

    As a continuation of the previous findings in human fetuses, accidental finding of an accessory vascular component in the posterior part of CAC of human adult cadavers inspired the authors to present and compare its posterior part configuration. Examination was carried out on brains of 48 human adult cadavers, routinely dissected at the Institute of Forensic Medicine. The aberrant vessel in the posterior part of four CACs was discovered.Vascular components of the posterior segment of CAC or of the whole CAC were described and photographed. A comparison between fetal and adult cases was also presented. Based on the fact that the age of the four presented cases ranged from 73 to 84 and based on the causes of their death, we concluded that the angioarchitecture of the posterior part of the CAC is a consequence of the embryonic or primitive arterial stabilization and interaction with normal adult vessels.

  12. Impact of Changes in Barometric Pressure on Landfill Methane Emission

    NASA Astrophysics Data System (ADS)

    McDermitt, Dayle; Xu, Liukang; Lin, Xiaomao; Amen, Jim; Welding, Karla

    2013-04-01

    Landfill methane emissions were measured continuously using the eddy covariance method from June to December 2010. The study site was located at the Bluff Road Landfill in Lincoln, Nebraska USA. Methane emissions strongly depended on changes in barometric pressure; rising barometric pressure suppressed the emission, while falling barometric pressure enhanced the emission. Emission rates were systematically higher in December than during the summer period. Higher methane emission rates were associated with changes in barometric pressure that were larger in magnitude and longer in duration in winter than in summer, and with lower mean temperatures, which appeared to reduce methane oxidation rates. Sharp changes in barometric pressure caused up to 35-fold variation in day-to-day methane emissions. Power spectrum and ogive analysis showed that continuous measurements over a period of at least 10 days were needed in order to capture 90% of total variance in the methane emission time series at our site. Our results suggest that point-in-time methane emission rate measurements taken at monthly or even longer time intervals using techniques such as the tracer plume method, the mass balance method, or the closed-chamber method may be subject to large variations because of the strong dependence of methane emissions on changes in barometric pressure. Estimates of long-term integrated methane emissions from landfills based on such measurements will inevitably yield large uncertainties. Our results demonstrate the value of continuous measurements for quantifying total annual methane emission from a landfill.

  13. Methane photochemistry and methane production on Neptune

    SciTech Connect

    Romani, P.N.; Atreya, S.K.

    1988-06-01

    The Neptune stratosphere's methane photochemistry is presently studied by means of a numerical model in which the observed mixing ratio of methane prompts photolysis near the CH4 homopause. Haze generation by methane photochemistry has its basis in the formation of hydrocarbon ices and polyacetylenes; the hazes can furnish the requisite aerosol haze at the appropriate pressure levels required by observations of Neptune in the visible and near-IR. Comparisons of model predictions with Uranus data indicate a lower ratio of polyacetylene production to hydrocarbon ice, as well as a lower likelihood of UV postprocessing of the acetylene ice to polymers on Neptune, compared to Uranus. 65 references.

  14. Methane photochemistry and methane production on Neptune

    NASA Astrophysics Data System (ADS)

    Romani, P. N.; Atreya, S. K.

    1988-06-01

    The Neptune stratosphere's methane photochemistry is presently studied by means of a numerical model in which the observed mixing ratio of methane prompts photolysis near the CH4 homopause. Haze generation by methane photochemistry has its basis in the formation of hydrocarbon ices and polyacetylenes; the hazes can furnish the requisite aerosol haze at the appropriate pressure levels required by observations of Neptune in the visible and near-IR. Comparisons of model predictions with Uranus data indicate a lower ratio of polyacetylene production to hydrocarbon ice, as well as a lower likelihood of UV postprocessing of the acetylene ice to polymers on Neptune, compared to Uranus.

  15. Methane photochemistry and methane production on Neptune

    NASA Technical Reports Server (NTRS)

    Romani, P. N.; Atreya, S. K.

    1988-01-01

    The Neptune stratosphere's methane photochemistry is presently studied by means of a numerical model in which the observed mixing ratio of methane prompts photolysis near the CH4 homopause. Haze generation by methane photochemistry has its basis in the formation of hydrocarbon ices and polyacetylenes; the hazes can furnish the requisite aerosol haze at the appropriate pressure levels required by observations of Neptune in the visible and near-IR. Comparisons of model predictions with Uranus data indicate a lower ratio of polyacetylene production to hydrocarbon ice, as well as a lower likelihood of UV postprocessing of the acetylene ice to polymers on Neptune, compared to Uranus.

  16. Methane photochemistry and methane production on Neptune

    NASA Technical Reports Server (NTRS)

    Romani, P. N.; Atreya, S. K.

    1988-01-01

    The Neptune stratosphere's methane photochemistry is presently studied by means of a numerical model in which the observed mixing ratio of methane prompts photolysis near the CH4 homopause. Haze generation by methane photochemistry has its basis in the formation of hydrocarbon ices and polyacetylenes; the hazes can furnish the requisite aerosol haze at the appropriate pressure levels required by observations of Neptune in the visible and near-IR. Comparisons of model predictions with Uranus data indicate a lower ratio of polyacetylene production to hydrocarbon ice, as well as a lower likelihood of UV postprocessing of the acetylene ice to polymers on Neptune, compared to Uranus.

  17. Clumped Methane Isotopologue Temperatures of Microbial Methane

    NASA Astrophysics Data System (ADS)

    Ono, S.; Wang, D. T.; Gruen, D.; Delwiche, K.; Hemond, H.; Pohlman, J.

    2014-12-01

    We will report the abundance of 13CH3D, a clumped isotopologue of methane, in microbial methane sampled from natural environments. They yield some expected and some unexpected results reflecting both equilibrium and kinetic isotope effects controlling the abundance of 13CH3D in low temperature environments. The four isotopologues of methane (12CH4, 13CH4, 12CH3D and 13CH3D) were measured by a tunable infrared spectroscopy method at a precision of 0.2‰ and accuracy of 0.5‰ (Ono et al., 2014). Similar to carbonate clumped isotope thermometry, clumped isotopologues of methane become more stable at lower temperatures. The equilibrium constant for the isotope exchange reaction 13CH4 + 12CH3D ⇌ 13CH3D + 12CH4 deviates from unity by +6.3 to +3.5 ‰ for methane equilibrated between 4 and 121 °C, a range expected for microbial methanogenesis. This would be measurably-distinct from a thermogenic methane signal, which typically have apparent 13CH3D-based temperatures ranging from 150 to 220 °C (+3.0 to +2.2 ‰ clumped isotope effect; Ono et al., 2014; Stolper et al. 2014). Marine samples, such as methane clathrates and porewater methane from the Cascadia margin, have 13CH3D-based temperatures that appear to be consistent with isotopic equilibration at in situ temperatures that are reasonable for deep sedimentary environments. In contrast, methane from freshwater environments, such as a lake and a swamp, yield apparent temperatures that are much higher than the known or inferred environmental temperature. Mixing of two or more distinct sources of methane could potentially generate this high temperature bias. We suggest, however, that this high-temperature bias likely reflects a kinetic isotope fractionation intrinsic to methanogenesis in fresh water environments. In contrast, the low-temperature signals from marine methane could be related to the slow metabolic rates and reversibility of microbial methanogenesis and methanotrophy in marine sedimentary environments

  18. Methane on Mars: Measurements and Possible Origins

    NASA Technical Reports Server (NTRS)

    Mumma, Michael J.; Villanueva, Geronimo L.; Novak, Robert E.; Radeva, Yana L.; Kaufl, H. Ulrich; Tokunaga, Alan; Encrenaz, Therese; Hartogh, Paul

    2011-01-01

    The presence of abundant methane in Earth's atmosphere (1.6 parts per million) requires sources other than atmospheric chemistry. Living systems produce more than 90% of Earth's atmospheric methane; the balance is of geochemical origin. On Mars, methane has been sought for nearly 40 years because of its potential biological significance, but it was detected only recently [1-5]. Its distribution on the planet is found to be patchy and to vary with time [1,2,4,5], suggesting that methane is released recently from the subsurface in localized areas, and is then rapidly destroyed [1,6]. Before 2000, searchers obtained sensitive upper limits for methane by averaging over much of Mars' dayside hemisphere, using data acquired by Marsorbiting spacecraft (Mariner 9) and Earth-based observatories (Kitt Peak National Observatory, Canada- France-Hawaii Telescope, Infrared Space Observatory). These negative findings suggested that methane should be searched at higher spatial resolution since the local abundance could be significantly larger at active sites. Since 2001, searches for methane have emphasized spatial mapping from terrestrial observatories and from Mars orbit (Mars Express).

  19. Process for separating nitrogen from methane using microchannel process technology

    DOEpatents

    Tonkovich, Anna Lee; Qiu, Dongming; Dritz, Terence Andrew; Neagle, Paul; Litt, Robert Dwayne; Arora, Ravi; Lamont, Michael Jay; Pagnotto, Kristina M.

    2007-07-31

    The disclosed invention relates to a process for separating methane or nitrogen from a fluid mixture comprising methane and nitrogen, the process comprising: (A) flowing the fluid mixture into a microchannel separator, the microchannel separator comprising a plurality of process microchannels containing a sorption medium, the fluid mixture being maintained in the microchannel separator until at least part of the methane or nitrogen is sorbed by the sorption medium, and removing non-sorbed parts of the fluid mixture from the microchannel separator; and (B) desorbing the methane or nitrogen from the sorption medium and removing the desorbed methane or nitrogen from the microchannel separator. The process is suitable for upgrading methane from coal mines, landfills, and other sub-quality sources.

  20. High-resolution passive sampling of dissolved methane in the water column of lakes in Greenland

    NASA Astrophysics Data System (ADS)

    Goldman, A. E.; Cadieux, S. B.; White, J. R.; Pratt, L. M.

    2013-12-01

    Arctic lakes are important participants in the global carbon cycle, releasing methane in a warming climate and contributing to a positive feedback to climate change. In order to yield detailed methane budgets and understand the implications of warming on methane dynamics, high-resolution profiles revealing methane behavior within the water column need to be obtained. Single day sampling using disruptive techniques has the potential to result in biases. In order to obtain high-resolution, undisturbed profiles of methane concentration and isotopic composition, this study evaluates a passive sampling method over a multi-day equilibration period. Selected for this study were two small lakes (<1km2) within a narrow valley stretching between Russells Glacier and Søndre Strømfjord in southwestern Greenland, which are part of an ongoing study of a series of seven lakes. Commercially available, 150 mL, polyethylene Passive Diffusion Bags (PDB's) were deployed in July 2013 for five days at 0.5-meter depth intervals. PDB samples were compared to samples collected with a submersible, electric pump taken immediately before PBD deployment. Preliminary CH4 concentrations and carbon isotopes for one lake were obtained in the field using a Los Gatos Research Methane Carbon Isotope Analyzer. PDB sampling and pump sampling resulted in statistically similar concentrations (R2=0.89), ranging from 0.85 to 135 uM from PDB and 0.74 to 143 uM from pump sampling. In anoxic waters of the lake, where concentrations were high enough to yield robust isotopic results on the LGR MCIA, δ13C were also similar between the two methods, yielding -73‰ from PDB and -74‰ from pump sampling. Further investigation will produce results for a second lake and methane carbon and hydrogen isotopic composition for both lakes. Preliminary results for this passive sampling method are promising. We envision the use of this technique in future studies of dissolved methane and expect that it will provide a

  1. Methane emission from sewers.

    PubMed

    Liu, Yiwen; Ni, Bing-Jie; Sharma, Keshab R; Yuan, Zhiguo

    2015-08-15

    Recent studies have shown that sewer systems produce and emit a significant amount of methane. Methanogens produce methane under anaerobic conditions in sewer biofilms and sediments, and the stratification of methanogens and sulfate-reducing bacteria may explain the simultaneous production of methane and sulfide in sewers. No significant methane sinks or methanotrophic activities have been identified in sewers to date. Therefore, most of the methane would be emitted at the interface between sewage and atmosphere in gravity sewers, pumping stations, and inlets of wastewater treatment plants, although oxidation of methane in the aeration basin of a wastewater treatment plant has been reported recently. Online measurements have also revealed highly dynamic temporal and spatial variations in methane production caused by factors such as hydraulic retention time, area-to-volume ratio, temperature, and concentration of organic matter in sewage. Both mechanistic and empirical models have been proposed to predict methane production in sewers. Due to the sensitivity of methanogens to environmental conditions, most of the chemicals effective in controlling sulfide in sewers also suppress or diminish methane production. In this paper, we review the recent studies on methane emission from sewers, including the production mechanisms, quantification, modeling, and mitigation.

  2. Freshwater bacteria release methane as a byproduct of phosphorus acquisition.

    PubMed

    Yao, Mengyin; Henny, Cynthia; Maresca, Julia A

    2016-09-30

    Freshwater lakes emit large amounts of methane, some of which is produced in oxic surface waters. Two potential pathways for aerobic methane production exist: methanogenesis in oxygenated water, which has been observed in some lakes, or demethylation of small organic molecules. Although methane is produced via demethylation in oxic marine environments, this mechanism of methane release has not yet been demonstrated in freshwater systems. Genes related to the C-P lyase pathway, which cleaves C-P bonds in phosphonate compounds, were found in a metagenomic survey of the surface water of Lake Matano, which is chronically P-starved and methane-rich. We demonstrate that four bacterial isolates from Lake Matano obtain P from methylphosphonate and release methane, and that this activity is repressed by phosphate. We further demonstrate that expression of phnJ, which encodes the enzyme that releases methane, is higher in the presence of methylphosphonate and lower when both methylphosphonate and phosphate are added. This gene is also found in most of the metagenomic data sets from freshwater environments. These experiments link methylphosphonate degradation and methane production with gene expression and phosphate availability in freshwater organisms, and suggest that some of the excess methane in the Lake Matano surface water, and in other methane-rich lakes, may be produced by P-starved bacteria. Methane is an important greenhouse gas, and contributes substantially to global warming. Although freshwater environments are known to release methane into the atmosphere, estimates of the amount of methane emitted by freshwater lakes vary from 8 to 73 Tg per year. Methane emissions are difficult to predict in part because the source of the methane can vary: it is the end product of the energy-conserving pathway in methanogenic archaea, which predominantly live in anoxic sediments or waters, but have also been identified in some oxic freshwater environments. More recently

  3. Detection of methane in the atmosphere of Mars.

    PubMed

    Formisano, Vittorio; Atreya, Sushil; Encrenaz, Thérèse; Ignatiev, Nikolai; Giuranna, Marco

    2004-12-03

    We report a detection of methane in the martian atmosphere by the Planetary Fourier Spectrometer onboard the Mars Express spacecraft. The global average methane mixing ratio is found to be 10 +/- 5 parts per billion by volume (ppbv). However, the mixing ratio varies between 0 and 30 ppbv over the planet. The source of methane could be either biogenic or nonbiogenic, including past or present subsurface microorganisms, hydrothermal activity, or cometary impacts.

  4. Spatially explicit methane inventory for Switzerland

    NASA Astrophysics Data System (ADS)

    Hiller, Rebecca; Bretscher, Daniel; DelSontro, Tonya; Eugster, Werner; Henne, Stephan; Henneberger, Ruth; Künzle, Thomas; Merbold, Lutz; Neininger, Bruno; Schellenberger, Andreas; Schroth, Martin; Buchmann, Nina; Brunner1, Dominik

    2013-04-01

    Spatially explicit greenhouse gas inventories are gaining in importance as a tool for policy makers to plan and control mitigation measures, and are a required input for atmospheric models used to relate atmospheric concentration measurements with upstream sources. In order to represent the high spatial heterogeneity in Switzerland, we compiled the national methane inventory into a 500 m x 500 m cadaster. In addition to the anthropogenic emissions reported to the United Nation Framework Convention on Climate Change (UNFCCC), we also included natural and semi-natural methane fluxes, i.e., emissions from lakes and reservoirs, wetlands, wild animals as well as forest uptake. Methane emissions were disaggregated according to geostatistical information about source location and extent. In Switzerland, highest methane emissions originate from the agricultural sector (152 Gg CH4 yr-1), followed by emissions from waste management (16 Gg CH4 yr-1) with highest contributions from landfills, and the energy sector (13 Gg CH4 yr-1) with highest contributions from the distribution of natural gas. Natural and semi-natural emissions only add a small amount (< 5%) to the total Swiss emissions. For validation, the bottom-up inventory was evaluated against methane concentrations measured from a small research aircraft (METAIR-DIMO) above the Swiss Plateau on 18 different days from May 2009 to August 2010 over. Source sensitivities of the air measured were determined by backward runs of the Lagrangian particle dispersion model FLEXPART-COSMO. Source sensitivities were multiplied with the methane inventory to derive simulated methane concentration time series. While the pattern of the variations can be reproduced well for some flight days (correlation coefficient up to 0.75), the amplitude of the variations for the simulated time series is underestimated by at least 20% suggesting an underestimation of CH4 emissions by the inventory, which is also concluded from inverse estimation

  5. Regolith production and transport in the Susquehanna Shale Hills Critical Zone Observatory, Part 1: Insights from U-series isotopes

    NASA Astrophysics Data System (ADS)

    Ma, Lin; Chabaux, Francois; West, Nikki; Kirby, Eric; Jin, Lixin; Brantley, Susan

    2013-06-01

    investigate the timescales of regolith formation on hillslopes with contrasting topographic aspect, we measured U-series isotopes in regolith profiles from two hillslopes (north facing versus south facing) within the east-west trending Shale Hills catchment in Pennsylvania. This catchment is developed entirely on the Fe-rich, Silurian Rose Hill gray shale. Hillslopes exhibit a topographic asymmetry: The north-facing hillslope has an average slope gradient of 20°, slightly steeper than the south-facing hillslope ( 15°). The regolith samples display significant U-series disequilibrium resulting from shale weathering. Based on the U-series data, the rates of regolith production on the two ridgetops are indistinguishable (40 ± 22 versus 45 ± 12 m/Ma). However, when downslope positions are compared, the regolith profiles on the south-facing hillslope are characterized by faster regolith production rates (50 ± 15 to 52 ± 15 m/Ma) and shorter durations of chemical weathering (12 ± 3 to 16 ± 5 ka) than those on the north-facing hillslope (17 ± 14 to 18 ± 13 m/Ma and 39 ± 20 to 43 ± 20 ka). The south-facing hillslope is also characterized by faster chemical weathering rates inferred from major element chemistry, despite lower extents of chemical depletion. These results are consistent with the influence of aspect on regolith formation at Shale Hills; we hypothesize that aspect affects such variables as temperature, moisture content, and evapotranspiration in the regolith zone, causing faster chemical weathering and regolith formation rates on the south-facing side of the catchment. The difference in microclimate between these two hillslopes is inferred to have been especially significant during the periglacial period that occurred at Shale Hills at least 15 ka before present. At that time, the erosion rates may also have been different from those observed today, perhaps denuding the south-facing hillslope of regolith but not quite stripping the north

  6. IUPAC-NIST Solubility Data Series. 101. Alcohols + Hydrocarbons + Water. Part 2. C1-C3 Alcohols + Aliphatic Hydrocarbons

    NASA Astrophysics Data System (ADS)

    Oracz, Paweł; Góral, Marian; Wiśniewska-Gocłowska, Barbara; Shaw, David G.; Mączyński, Andrzej

    2016-09-01

    The mutual solubilities and related liquid-liquid equilibria for 37 ternary systems of C1-C3 alcohols with aliphatic hydrocarbons and water are exhaustively and critically reviewed. Reports of experimental determination of solubility that appeared in the primary literature prior to the end of 2012 are compiled. For 14 systems, sufficient data are available (two or more independent determinations) to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, an additional criterion was used for each of the evaluated systems. These systems include one binary miscibility gap in the hydrocarbon + water subsystem and another one can be in the methanol + hydrocarbon subsystem. The binary tie lines were compared with the recommended values published previously.

  7. IUPAC-NIST Solubility Data Series. 101. Alcohols + Hydrocarbons + Water Part 3. C1-C3 Alcohols + Aromatic Hydrocarbons

    NASA Astrophysics Data System (ADS)

    Oracz, Paweł; Góral, Marian; Wiśniewska-Gocłowska, Barbara; Shaw, David G.; Mączyński, Andrzej

    2016-09-01

    The mutual solubilities and related liquid-liquid equilibria for 11 ternary systems of C1-C3 alcohols with aromatic hydrocarbons and water are exhaustively and critically reviewed. Reports of experimental determination of solubility that appeared in the primary literature prior to the end of 2012 are compiled. For nine systems, sufficient data are available (two or more independent determinations) to allow critical evaluation. All new data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, an additional criterion was used for each of the evaluated systems. These systems include one binary miscibility gap in the hydrocarbon + water subsystem. The binary tie lines were compared with the recommended values published previously.

  8. An Interview Series with Members of the ASHP Expert Panel on Formulary Management: Part 3: Sabrina W. Cole, PharmD.

    PubMed

    Ventola, C Lee

    2010-01-01

    This article presents the third in a series of three interviews that P&T conducted with several members of the American Society of Health-System Pharmacists (ASHP) Expert Panel on Formulary Management.In 2008, ASHP convened this panel of experts to develop revised guidelines for P&T committee and formulary management to replace the previous guidance issued in 1991.1 These revised guidelines include recommendations concerning the review and evaluation of drugs for formulary inclusion, pharmacoeconomic assessments, therapeutic interchange, medication-use evaluations (MUEs), management of drug shortages, and many other important topics.In this series, ASHP experts discuss P&T committee and formulary management guidelines in their respective institutions as well as other observations and insights. In Part 3, the author interviews Sabrina Cole, PharmD, Clinical Specialist, Drug Information, at the Grady Health System in Atlanta, Georgia.

  9. Temporal variability of methane fluxes in West Siberian taiga bogs and its implications for estimating regional methane emission

    NASA Astrophysics Data System (ADS)

    Sabrekov, Alexander; Ilyasov, Danil; Terentieva, Irina; Glagolev, Mikhail; Maksyutov, Shamil

    2017-04-01

    The West Siberia Lowland (WSL) is the biggest peatland area in Eurasia and is situated in the high latitudes experiencing enhanced rate of climate change. During 2015-16 summer periods, seasonal measurements of methane emission were made at the field station «Mukhrino» in the WSL middle taiga zone. The study was made at 3 wetland ecosystem types covering 80% of the taiga wetland area: i) waterlogged hollows or depressed areas with water level above the moss surface, ii) oligotrophic hollows or depressed parts of bogs with water level beneath the moss surface, iii) forested bogs with dwarf shrubs-sphagnum vegetation. Seven series of measurements were made by a static chamber method in 2016 and four series - in 2015. In 2015, we observed non-typical weather conditions including early dry spring and short cold rainy summer. Oppositely, weather conditions in 2016 were closer to average long-term with warmer drier summer. Significant difference between these years allowed analyzing the temporal variability and its sources. Average methane flux rates from forested bogs were 0.57 mgCH4/m2/h in 2016 and 0.33 mgCH4/m2/h in 2015. Seasonal dynamic during both years had similar concave downward shape. The highest fluxes were observed in June and were corresponded to the highest WTL, the main limiting factor of emission from forested bogs. The lowest fluxes in July were related to the low WTL combining with the highest temperature of upper methanotrophy layer. Average methane flux rates from oligotrophic hollows were 7.18 mgCH4/m2/h in 2016 and 4.28 mgCH4/m2/h in 2015. Seasonal dynamic of methane emission was indistinct in 2015. On the contrary, in 2016 it had regular seasonal pattern with peak emissions in July, which were four times higher than in 2015. WTL was not the limiting factor for CH4 emission from oligotrophic hollows, because even in the driest ones it was only 10 cm below the surface. Thus, the difference between peak emissions in 2015 and 2016 was mainly related

  10. Methane-Powered Vehicles

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Liquid methane is beginning to become an energy alternative to expensive oil as a power source for automotive vehicles. Methane is the principal component of natural gas, costs less than half as much as gasoline, and its emissions are a lot cleaner than from gasoline or diesel engines. Beech Aircraft Corporation's Boulder Division has designed and is producing a system for converting cars and trucks to liquid methane operation. Liquid methane (LM) is a cryogenic fuel which must be stored at a temperature of 260 degrees below zero Fahrenheit. The LM system includes an 18 gallon fuel tank in the trunk and simple "under the hood" carburetor conversion equipment. Optional twin-fuel system allows operator to use either LM or gasoline fuel. Boulder Division has started deliveries for 25 vehicle conversions and is furnishing a liquid methane refueling station. Beech is providing instruction for Northwest Natural Gas, for conversion of methane to liquid state.

  11. Mars methane engine

    NASA Technical Reports Server (NTRS)

    Bui, Hung; Coletta, Chris; Debois, Alain

    1994-01-01

    The feasibility of an internal combustion engine operating on a mixture of methane, carbon dioxide, and oxygen has been verified by previous design groups for the Mars Methane Engine Project. Preliminary stoichiometric calculations examined the theoretical fuel-air ratios needed for the combustion of methane. Installation of a computer data acquisition system along with various ancillary components will enable the performance of the engine, running on the described methane mixture, to be optimized with respect to minimizing excess fuel. Theoretical calculations for stoichiometric combustion of methane-oxygen-carbon dioxide mixtures yielded a ratio of 1:2:4.79 for a methane-oxygen-carbon dioxide mixture. Empirical data shows the values to be closer to 1:2.33:3.69 for optimum operation.

  12. Oceanographic Data Report for South West Pacific Cruises in the SEAMAP Series. Part 1. Summer Survey Data 1984 to 1987

    DTIC Science & Technology

    1988-09-01

    The CTD data were obtained with a Plessey model 9041 instrument havinvg a sampling rate of 1.66 Hz, conductivity and temperature resolutions of 0.005...scope of the present investigations. In the context of the present analysis, Fig. 7 can be regarded as a partly speculative model that could explain...some of the observed thermohaline structure associated with the main Tasman Frofit. 150 °E -170 Fig. 7. Proposed model of the Tasman Front in the western

  13. Methane emissions from cattle.

    PubMed

    Johnson, K A; Johnson, D E

    1995-08-01

    Increasing atmospheric concentrations of methane have led scientists to examine its sources of origin. Ruminant livestock can produce 250 to 500 L of methane per day. This level of production results in estimates of the contribution by cattle to global warming that may occur in the next 50 to 100 yr to be a little less than 2%. Many factors influence methane emissions from cattle and include the following: level of feed intake, type of carbohydrate in the diet, feed processing, addition of lipids or ionophores to the diet, and alterations in the ruminal microflora. Manipulation of these factors can reduce methane emissions from cattle. Many techniques exist to quantify methane emissions from individual or groups of animals. Enclosure techniques are precise but require trained animals and may limit animal movement. Isotopic and nonisotopic tracer techniques may also be used effectively. Prediction equations based on fermentation balance or feed characteristics have been used to estimate methane production. These equations are useful, but the assumptions and conditions that must be met for each equation limit their ability to accurately predict methane production. Methane production from groups of animals can be measured by mass balance, micrometeorological, or tracer methods. These techniques can measure methane emissions from animals in either indoor or outdoor enclosures. Use of these techniques and knowledge of the factors that impact methane production can result in the development of mitigation strategies to reduce methane losses by cattle. Implementation of these strategies should result in enhanced animal productivity and decreased contributions by cattle to the atmospheric methane budget.

  14. Detecting Methane Leaks

    NASA Technical Reports Server (NTRS)

    Grant, W. B.; Hinkley, E. D.

    1984-01-01

    Remote sensor uses laser radiation backscattered from natural targets. He/Ne Laser System for remote scanning of Methane leaks employs topographic target to scatter light to receiver near laser transmitter. Apparatus powered by 1.5kW generator transported to field sites and pointed at suspected methane leaks. Used for remote detection of natural-gas leaks and locating methane emissions in landfill sites.

  15. Multisensor technologies for low cost methane detection

    NASA Astrophysics Data System (ADS)

    Clifford, P. K.; Dorman, M. G.

    1988-11-01

    The study lays the technical foundation necessary to quantitatively characterize array performance and to determine the number of sensors needed for false-alarm-free methane detection. A technique was developed to quantitate the performances of sensor arrays. This technique was verified using data from a series of experiments that measured the responses of metal oxide semiconductor sensing arrays to methane and representative interfering gases, carbon monoxide and ammonia. Arrays of as few as two or three properly chosen sensors exhibit excellent immunity to false alarms. Further experiments show that arrays demonstrate good selectivity and low false alarm rates even after significant drift of sensor characteristics.

  16. Efficient Algorithm for Locating and Sizing Series Compensation Devices in Large Transmission Grids: Model Implementation (PART 1)

    SciTech Connect

    Frolov, Vladimir; Backhaus, Scott N.; Chertkov, Michael

    2014-01-14

    We explore optimization methods for planning the placement, sizing and operations of Flexible Alternating Current Transmission System (FACTS) devices installed to relieve transmission grid congestion. We limit our selection of FACTS devices to Series Compensation (SC) devices that can be represented by modification of the inductance of transmission lines. Our master optimization problem minimizes the l1 norm of the inductance modification subject to the usual line thermal-limit constraints. We develop heuristics that reduce this non-convex optimization to a succession of Linear Programs (LP) which are accelerated further using cutting plane methods. The algorithm solves an instance of the MatPower Polish Grid model (3299 lines and 2746 nodes) in 40 seconds per iteration on a standard laptop—a speed up that allows the sizing and placement of a family of SC devices to correct a large set of anticipated congestions. We observe that our algorithm finds feasible solutions that are always sparse, i.e., SC devices are placed on only a few lines. In a companion manuscript, we demonstrate our approach on realistically-sized networks that suffer congestion from a range of causes including generator retirement. In this manuscript, we focus on the development of our approach, investigate its structure on a small test system subject to congestion from uniform load growth, and demonstrate computational efficiency on a realistically-sized network.

  17. Efficient Algorithm for Locating and Sizing Series Compensation Devices in Large Transmission Grids: Solutions and Applications (PART II)

    SciTech Connect

    Frolov, Vladimir; Backhaus, Scott N.; Chertkov, Michael

    2014-01-14

    In a companion manuscript, we developed a novel optimization method for placement, sizing, and operation of Flexible Alternating Current Transmission System (FACTS) devices to relieve transmission network congestion. Specifically, we addressed FACTS that provide Series Compensation (SC) via modification of line inductance. In this manuscript, this heuristic algorithm and its solutions are explored on a number of test cases: a 30-bus test network and a realistically-sized model of the Polish grid (~2700 nodes and ~3300 lines). The results on the 30-bus network are used to study the general properties of the solutions including non-locality and sparsity. The Polish grid is used as a demonstration of the computational efficiency of the heuristics that leverages sequential linearization of power flow constraints and cutting plane methods that take advantage of the sparse nature of the SC placement solutions. Using these approaches, the algorithm is able to solve an instance of Polish grid in tens of seconds. We explore the utility of the algorithm by analyzing transmission networks congested by (a) uniform load growth, (b) multiple overloaded configurations, and (c) sequential generator retirements

  18. Solar Energy Education. Reader, Part IV. Sun schooling

    SciTech Connect

    Not Available

    1981-05-01

    A collection of magazine articles which focus on solar energy is presented. This is the final book of the four part series of the Solar Energy Reader. The articles include brief discussions on energy topics such as the sun, ocean energy, methane gas from cow manure, and solar homes. Instructions for constructing a sundial and a solar stove are also included. A glossary of energy related terms is provided. (BCS)

  19. A conduit dilation model of methane venting from lake sediments

    USGS Publications Warehouse

    Scandella, B.P.; Varadharajan, C.; Hemond, Harold F.; Ruppel, C.; Juanes, R.

    2011-01-01

    Methane is a potent greenhouse gas, but its effects on Earth's climate remain poorly constrained, in part due to uncertainties in global methane fluxes to the atmosphere. An important source of atmospheric methane is the methane generated in organic-rich sediments underlying surface water bodies, including lakes, wetlands, and the ocean. The fraction of the methane that reaches the atmosphere depends critically on the mode and spatiotemporal characteristics of free-gas venting from the underlying sediments. Here we propose that methane transport in lake sediments is controlled by dynamic conduits, which dilate and release gas as the falling hydrostatic pressure reduces the effective stress below the tensile strength of the sediments. We test our model against a four-month record of hydrostatic load and methane flux in Upper Mystic Lake, Mass., USA, and show that it captures the complex episodicity of methane ebullition. Our quantitative conceptualization opens the door to integrated modeling of methane transport to constrain global methane release from lakes and other shallow-water, organic-rich sediment systems, and to assess its climate feedbacks.

  20. A conduit dilation model of methane venting from lake sediments

    NASA Astrophysics Data System (ADS)

    Scandella, Benjamin P.; Varadharajan, Charuleka; Hemond, Harold F.; Ruppel, Carolyn; Juanes, Ruben

    2011-03-01

    Methane is a potent greenhouse gas, but its effects on Earth's climate remain poorly constrained, in part due to uncertainties in global methane fluxes to the atmosphere. An important source of atmospheric methane is the methane generated in organic-rich sediments underlying surface water bodies, including lakes, wetlands, and the ocean. The fraction of the methane that reaches the atmosphere depends critically on the mode and spatiotemporal characteristics of free-gas venting from the underlying sediments. Here we propose that methane transport in lake sediments is controlled by dynamic conduits, which dilate and release gas as the falling hydrostatic pressure reduces the effective stress below the tensile strength of the sediments. We test our model against a four-month record of hydrostatic load and methane flux in Upper Mystic Lake, Mass., USA, and show that it captures the complex episodicity of methane ebullition. Our quantitative conceptualization opens the door to integrated modeling of methane transport to constrain global methane release from lakes and other shallow-water, organic-rich sediment systems, and to assess its climate feedbacks.

  1. Applications of a simulation model to description of anaerobic conversion of complex organic matter into methane

    SciTech Connect

    Vavilin, V.A.; Rytow, S.V.; Lokshina, L.Ya.

    1996-12-31

    Three years passed since the generalized model <METHANE> of anaerobic degradation of complex organic matter has been developed. Now the new modifications were created. Anaerobic degradation was described as a multistep process of series and parallel reactions in which several groups of bacteria take part. Hydrolysis, acidogenesis, acetogenesis and methanogenesis were considered in the model with the various kinetic functions. A two-phase equation describing a particulate substrate degradation as a heterogeneous reaction has been developed. Acetic, butyric, and propionic groups of acidogenic bacteria producing the particular products were considered. The additional group of homoacetogenic bacteria producing acetate from hydrogen and carbon dioxide was involved into new version of the <METHANE> model. Ammonia and hydrogen sulfide inhibition were described previously. In that paper, it was shown by simulation of several case-studies that unionized volatile fatty acids (VFA) are the inhibitors of key stages of anaerobic conversion of complex organic matter: hydrolysis, acetogenesis and methanogenesis.

  2. The future of methane

    SciTech Connect

    Howell, D.G.

    1995-12-31

    Natural gas, mainly methane, produces lower CO{sub 2}, CO, NO{sub x}, SO{sub 2} and particulate emissions than either oil or coal; thus further substitutions of methane for these fuels could help mitigate air pollution. Methane is, however, a potent greenhouse gas and the domestication of ruminants, cultivation of rice, mining of coal, drilling for oil, and transportation of natural gas have all contributed to a doubling of the amount of atmospheric methane since 1800. Today nearly 300,000 wells yearly produce ca. 21 trillion cubic feet of methane. Known reserves suggest about a 10 year supply at the above rates of recovery; and the potential for undiscovered resources is obscured by uncertainty involving price, new technologies, and environmental restrictions steming from the need to drill an enormous number of wells, many in ecologically sensitive areas. Until all these aspects of methane are better understood, its future role in the world`s energy mix will remain uncertain. The atomic simplicity of methane, composed of one carbon and four hydrogen atoms, may mask the complexity and importance of this, the most basic of organic molecules. Within the Earth, methane is produced through thermochemical alteration of organic materials, and by biochemical reactions mediated by metabolic processes of archaebacteria; some methane may even be primordial, a residue of planetary accretion. Methane also occurs in smaller volumes in landfills, rice paddies, termite complexes, ruminants, and even many humans. As an energy source, its full energy potential is controversial. Methane is touted by some as a viable bridge to future energy systems, fueled by the sun and uranium and carried by electricity and hydrogen.

  3. Methanation assembly using multiple reactors

    DOEpatents

    Jahnke, Fred C.; Parab, Sanjay C.

    2007-07-24

    A methanation assembly for use with a water supply and a gas supply containing gas to be methanated in which a reactor assembly has a plurality of methanation reactors each for methanating gas input to the assembly and a gas delivery and cooling assembly adapted to deliver gas from the gas supply to each of said methanation reactors and to combine water from the water supply with the output of each methanation reactor being conveyed to a next methanation reactor and carry the mixture to such next methanation reactor.

  4. Effects of Environmental Conditions on an Urban Wetland's Methane Fluxes

    NASA Astrophysics Data System (ADS)

    Naor Azrieli, L.; Morin, T. H.; Bohrer, G.; Schafer, K. V.; Brooker, M.; Mitsch, W. J.

    2013-12-01

    Methane emissions from wetlands are the largest natural source of uncertainty in the global methane (CH4) budget. Wetlands are highly productive ecosystems with a large carbon sequestration potential. While wetlands are a net sink for carbon dioxide, they also release methane, a potent greenhouse gas. To effectively develop wetland management techniques, it is important to properly calculate the carbon budget of wetlands by understand the driving factors of methane fluxes. We constructed an eddy flux covariance system in the Olentangy River Wetland Research Park, a series of created and restored wetland in Columbus Ohio. Through the use of high frequency open path infrared gas analyzer (IRGA) sensors, we have continuously monitored the methane fluxes associated with the wetland since May 2011. To account for the heterogeneous landscape surrounding the tower, a footprint analysis was used to isolate data originating from within the wetland. Continuous measurements of the meteorological and environmental conditions at the wetlands coinciding with the flux measurements allow the interactions between methane fluxes and the climate and ecological forcing to be studied. The wintertime daily cycle of methane peaks around midday indicating a typical diurnal pattern in cold months. In the summer, the peak shifts to earlier in the day and also includes a daily peak occurring at approximately 10 AM. We believe this peak is associated with the onset of photosynthesis in Typha latifolia flushing methane from the plant's air filled tissue. Correlations with methane fluxes include latent heat flux, soil temperature, and incoming radiation. The connection to radiation may be further evidence of plant activity as a driver of methane fluxes. Higher methane fluxes corresponding with higher soil temperature indicates that warmer days stimulate the methanogenic consortium. Further analysis will focus on separating the methane fluxes into emissions from different terrain types within

  5. Methane emission from flooded soils - from microorganisms to the atmosphere

    NASA Astrophysics Data System (ADS)

    Conrad, Ralf

    2016-04-01

    Methane is an important greenhouse gas that is affected by anthropogenic activity. The annual budget of atmospheric methane, which is about 600 million tons, is by more than 75% produced by methanogenic archaea. These archaea are the end-members of a microbial community that degrades organic matter under anaerobic conditions. Flooded rice fields constitute a major source (about 10%) of atmospheric methane. After flooding of soil, anaerobic processes are initiated, finally resulting in the disproportionation of organic matter to carbon dioxide and methane. This process occurs in the bulk soil, on decaying organic debris and in the rhizosphere. The produced methane is mostly ventilated through the plant vascular system into the atmosphere. This system also allows the diffusion of oxygen into the rizosphere, where part of the produced methane is oxidized by aerobic methanotrophic bacteria. More than 50% of the methane production is derived from plant photosynthetic products and is formed on the root surface. Methanocellales are an important group of methanogenic archaea colonizing rice roots. Soils lacking this group seem to result in reduced root colonization and methane production. In rice soil methane is produced by two major paths of methanogenesis, the hydrogenotrophic one reducing carbon dioxide to methane, and the aceticlastic one disproportionating acetate to methane and carbon dioxide. Theoretically, at least two third of the methane should be produced by aceticlastic and the rest by hydrogenotrophic methanogenesis. In nature, however, the exact contribution of the two paths can vary from zero to 100%. Several environmental factors, such as temperature and quality of organic matter affect the path of methane production. The impact of these factors on the composition and activity of the environmental methanogenic microbial community will be discussed.

  6. Geoengineering treatment of methane

    NASA Astrophysics Data System (ADS)

    Lockley, Andrew; Gardian, Alan

    2010-05-01

    Methane is a significant GHG, and substantial reservoirs are vulnerable to instability due to AGW. Excursions, from permafrost and clathrates especially, act a positive feedback to AGW. Existing concentrations of well-mixed atmospheric methane substantially exceed pre-industrial levels. Various geoengineering methods are herein proposed for containment of methane, and/or accelerated oxidation to CO2 (a gas with a lower GWP over all timescales). A basic qualitative analysis of each technique is undertaken, to direct further study. Consideration is also given to the potential capacity of each technique to treat the total likely excursions of methane expected as a result of AGW. Proposed techniques: Section 0 SRM (comparison option) Section 1 Pre-emptive treatment of methane reservoirs Soil heating (polytunnels, heat pumps); Soil aeration; Mining of clathrates; Burning of clathrates Section 2 Remediation of aquatic methane excursions Lake sealing; Mixing of aquatic strata; Bubble capture; Lake aeration; Biological oxidation in aquatic environments Section 3 Remediation of concentrated atmospheric methane Regenerative thermal oxidation; Electrical ignition; Thermal ignition; Using incendiary munitions Section 4 Remediation of diffuse atmospheric methane Thermal oxidation by concentrated solar power; Compression ignition; Chemical degradation Assessment criteria: Infrastructure/implementation cost; Energy cost; Expected efficacy; Complexity/development path; Environmental impacts; Potential for CCS

  7. 40 CFR Table Hh-4 to Subpart Hh of... - Landfill Methane Oxidation Fractions

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Landfill Methane Oxidation Fractions.... 98, Subpt. HH, Table HH-4 Table HH-4 to Subpart HH of Part 98—Landfill Methane Oxidation Fractions... soil prior to any oxidation and is calculated as follows: ER29NO13.024 Where: MF = Methane flux...

  8. 30 CFR 75.150 - Tests for methane and for oxygen deficiency; qualified person.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Tests for methane and for oxygen deficiency... Certified Persons § 75.150 Tests for methane and for oxygen deficiency; qualified person. (a) The provisions of Subpart D—Ventilation of this part and § 75.1106 require that tests for methane and for...

  9. 30 CFR 75.150 - Tests for methane and for oxygen deficiency; qualified person.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Tests for methane and for oxygen deficiency... Certified Persons § 75.150 Tests for methane and for oxygen deficiency; qualified person. (a) The provisions of Subpart D—Ventilation of this part and § 75.1106 require that tests for methane and for...

  10. 30 CFR 75.150 - Tests for methane and for oxygen deficiency; qualified person.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Tests for methane and for oxygen deficiency... Certified Persons § 75.150 Tests for methane and for oxygen deficiency; qualified person. (a) The provisions of Subpart D—Ventilation of this part and § 75.1106 require that tests for methane and for...

  11. 30 CFR 75.150 - Tests for methane and for oxygen deficiency; qualified person.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Tests for methane and for oxygen deficiency... Certified Persons § 75.150 Tests for methane and for oxygen deficiency; qualified person. (a) The provisions of Subpart D—Ventilation of this part and § 75.1106 require that tests for methane and for...

  12. 30 CFR 75.150 - Tests for methane and for oxygen deficiency; qualified person.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Tests for methane and for oxygen deficiency... Certified Persons § 75.150 Tests for methane and for oxygen deficiency; qualified person. (a) The provisions of Subpart D—Ventilation of this part and § 75.1106 require that tests for methane and for...

  13. IUPAC-NIST Solubility Data Series. 95. Alkaline Earth Carbonates in Aqueous Systems. Part 1. Introduction, Be and Mg

    NASA Astrophysics Data System (ADS)

    De Visscher, Alex; Vanderdeelen, Jan; Königsberger, Erich; Churagulov, Bulat R.; Ichikuni, Masami; Tsurumi, Makoto

    2012-03-01

    The alkaline earth carbonates are an important class of minerals. This volume compiles and critically evaluates solubility data of the alkaline earth carbonates in water and in simple aqueous electrolyte solutions. Part 1, the present paper, outlines the procedure adopted in this volume in detail, and presents the beryllium and magnesium carbonates. For the minerals magnesite (MgCO3), nesquehonite (MgCO3.3H2O), and lansfordite (MgCO3.5H2O), a critical evaluation is presented based on curve fits to empirical and/or thermodynamic models. Useful side products of the compilation and evaluation of the data outlined in the introduction are new relationships for the Henry constant of CO2 with Sechenov parameters, and for various equilibria in the aqueous phase including the dissociation constants of CO2(aq) and the stability constant of the ion pair MCO30(aq) (M = alkaline earth metal). Thermodynamic data of the alkaline earth carbonates consistent with two thermodynamic model variants are proposed. The model variant that describes the Mg2+-HCO3- ion interaction with Pitzer parameters was more consistent with the solubility data and with other thermodynamic data than the model variant that described the interaction with a stability constant.

  14. Genomic heritabilities and genomic estimated breeding values for methane traits in Angus cattle.

    PubMed

    Hayes, B J; Donoghue, K A; Reich, C M; Mason, B A; Bird-Gardiner, T; Herd, R M; Arthur, P F

    2016-03-01

    Enteric methane emissions from beef cattle are a significant component of total greenhouse gas emissions from agriculture. The variation between beef cattle in methane emissions is partly genetic, whether measured as methane production, methane yield (methane production/DMI), or residual methane production (observed methane production - expected methane production), with heritabilities ranging from 0.19 to 0.29. This suggests methane emissions could be reduced by selection. Given the high cost of measuring methane production from individual beef cattle, genomic selection is the most feasible approach to achieve this reduction in emissions. We derived genomic EBV (GEBV) for methane traits from a reference set of 747 Angus animals phenotyped for methane traits and genotyped for 630,000 SNP. The accuracy of GEBV was tested in a validation set of 273 Angus animals phenotyped for the same traits. Accuracies of GEBV ranged from 0.29 ± 0.06 for methane yield and 0.35 ± 0.06 for residual methane production. Selection on GEBV using the genomic prediction equations derived here could reduce emissions for Angus cattle by roughly 5% over 10 yr.

  15. Charters, Constitutions and By-Laws of the Indian Tribes of North America, Part X: The Northwest, and Alaska (cont'd.). Occasional Publications in Anthropology, Ethnology Series, No. 11.

    ERIC Educational Resources Information Center

    Fay, George E., Comp.

    The Museum of Anthropology, University of Northern Colorado at Greeley, has assembled various American Indian tribal charters, constitutions, and by-laws to comprise a series of publications. The present volume, Part I of the series, covers the following Northwest groups: the Hoh, Muckleshoot, Nisqually, Port Gamble Clallam, Lower Elwha, Puyallup,…

  16. The Search for Methane on Mars

    NASA Astrophysics Data System (ADS)

    Webster, C. R.; Mahaffy, P. R.; Atreya, S. K.; Flesch, G.; Farley, K. A.; Owen, T. C.; Leshin, L. A.; Stern, J. C.; Franz, H.; Eigenbrode, J. L.

    2013-12-01

    Abstract: Over the last several years, Earth-based telescopic and Mars orbit remote sensing instruments have reported significant abundances of methane on Mars ranging to tens of parts-per-billion by volume (ppbv). These observations have reported 'plumes' or localized patches of methane with variations on timescales much faster than model predictions, leading to speculation of sources from sub-surface methanogen bacteria, geological water-rock reactions, degassing of infalling comets, or UV degradation of micro-meteorites or interplanetary dust. More recently, these same groups report that the methane is no longer localized, and appears to have gone away, down to their detection limits of 7-8 ppbv. We will report in situ measurements made by the Tunable Laser Spectrometer (TLS) in the Sample Analysis at Mars (SAM) instrument suite on Curiosity at much higher sensitivity, and over the first year of operation. Additionally, we will report methane abundances and 13CH4 measurements from methane detected in our evolved gas experiments using martian rock drill samples and compare the measurement methods to those used for determining H, C and O isotope ratios in carbon dioxide and water. The research described here was carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (NASA).

  17. Modeling the Terrestrial Contribution to the Global Methane Balance

    NASA Astrophysics Data System (ADS)

    Smith, Amy Tetlow

    Most of the methane emitted into the atmosphere is produced microbiologically. Methanogenic bacteria in soils and sediments of natural wetlands are one of the largest sources of methane. The activity of these organisms is closely linked to environmental conditions. A climate -driven model of methane flux across the terrestrial surface is developed for analysis of atmosphere-biosphere interactions. The methane-flux model is based on temperature response of bacterial populations, and the requirement of anaerobic conditions for growth of methanogenic bacteria or the requirement of aerobic conditions for growth of methane-oxidizing bacteria. A biological inertia factor is also used to reflect dependence on previous bacterial conditions. Model parameters are fit for characteristic ecosystems based on the availability of appropriate time -series data. Using air temperature and precipitation climatologies as both direct and indirect model input, monthly methane fluxes are calculated for muskeg tundra, wet-meadow tundra, temperate and tropical wetlands, cool woods, and tropical savanna. Ecosystem models performed well in diverse environments. Annual -flux totals based on these models are consistent with published methane-budget estimates. To evaluate the global distribution of methane flux, emission estimates from rice cultivation, grazing animals, termites, biomass burning, and fossil fuel extraction and transportation are combined with the ecosystem-model estimates. The resulting global distribution of methane flux shows that the mid-latitudes of the northern hemisphere are the strongest methane source zone. Summer and fall are the most important emission seasons for in any latitudinal zone. My estimated atmospheric residence time of methane, calculated using this global-flux distribution, also agrees well with other published values.

  18. The evolution and distribution of methane in Lake Champlain sediments

    SciTech Connect

    Thibodeau, P.M. . Dept. of Geology)

    1993-03-01

    Regions of Lake Champlain sediments are acoustically impenetrable to the energy emitted from high resolution, low energy sub-bottom seismic profiling apparatus. This anomolous behavior is caused by the presence of interstitial methane gas which absorbs the wave energy and thus prevents the formation of well-defined seismic boundaries. Through gas chromatographic and carbon isotope analyses, the methane gas contained in the recent sediments of Lake Champlain has been demonstrated to be biogenic in origin. The production of biogenic methane occurs as a result of a series of coupled oxidation-reduction reactions occurring within the upper two meters beneath the sediment-water interface.

  19. Microbial methane consumption in the oligotrophic surface waters of the East Siberian Arctic Shelf

    NASA Astrophysics Data System (ADS)

    Joye, S. B.

    2011-12-01

    The East Siberian Arctic Shelf (ESAS) accounts for ten percent of the world ocean shelf area and is the shallowest shelf (average depth < 50m). This area is home to a tremendous stock of hydrocarbons, mostly as methane associated with shallow, permafrost-associated hydrates. Thus, the ESAS represents an enormous potential atmospheric methane source that could result from global warming-triggered permafrost destabilization; such a massive methane infusion to the atmosphere from the Arctic could exacerbate and/or accelerate global warming. Increased methane fluxes could occur as numerous weak seeps or strong bubble plumes over large areas. Due to the shallow, well-mixed nature of the ESAS and its oligotrophic waters, the majority of methane entering ESAS water may avoids microbial oxidation and escape to the atmosphere. As part of an international research effort that aims to describe the patterns and controls methane dynamics within the ESAS, we documented methane concentrations and methane oxidation rates and examined environmental and microbiological factors that could regulate methane oxidation activity. Methane concentrations varied spatially and temporally and surface water concentrations were substantially super-saturated at most sites. The highest methane concentrations observed were hundreds of nanomolar. Despite the relatively methane concentrations, methane oxidation rates, determined with tritium-labeled methane tracer, were low, ranging from 10's of picomoles per liter per day to 3 nanomoles per liter per day. By and large, the turnover time for the methane pool was hundreds to thousands of days, which means that methane would be vented to the atmosphere before it was microbially oxidized. The exception to this pattern was in fresh water near the mouth of a river, where methane oxidation rates were high such that the pool turnover time was roughly 4 days. Available data suggest that nutrient availability limits accumulation of methanotroph biomass and

  20. Crenothrix are major methane consumers in stratified lakes.

    PubMed

    Oswald, Kirsten; Graf, Jon S; Littmann, Sten; Tienken, Daniela; Brand, Andreas; Wehrli, Bernhard; Albertsen, Mads; Daims, Holger; Wagner, Michael; Kuypers, Marcel Mm; Schubert, Carsten J; Milucka, Jana

    2017-09-01

    Methane-oxidizing bacteria represent a major biological sink for methane and are thus Earth's natural protection against this potent greenhouse gas. Here we show that in two stratified freshwater lakes a substantial part of upward-diffusing methane was oxidized by filamentous gamma-proteobacteria related to Crenothrix polyspora. These filamentous bacteria have been known as contaminants of drinking water supplies since 1870, but their role in the environmental methane removal has remained unclear. While oxidizing methane, these organisms were assigned an 'unusual' methane monooxygenase (MMO), which was only distantly related to 'classical' MMO of gamma-proteobacterial methanotrophs. We now correct this assignment and show that Crenothrix encode a typical gamma-proteobacterial PmoA. Stable isotope labeling in combination swith single-cell imaging mass spectrometry revealed methane-dependent growth of the lacustrine Crenothrix with oxygen as well as under oxygen-deficient conditions. Crenothrix genomes encoded pathways for the respiration of oxygen as well as for the reduction of nitrate to N2O. The observed abundance and planktonic growth of Crenothrix suggest that these methanotrophs can act as a relevant biological sink for methane in stratified lakes and should be considered in the context of environmental removal of methane.

  1. Mapping Pluto Methane Ice

    NASA Image and Video Library

    2015-09-24

    The Ralph/LEISA infrared spectrometer on NASA's New Horizons spacecraft mapped compositions across Pluto's surface as it flew past the planet on July 14, 2015. On the left, a map of methane ice abundance shows striking regional differences, with stronger methane absorption indicated by the brighter purple colors, and lower abundances shown in black. Data have only been received so far for the left half of Pluto's disk. At right, the methane map is merged with higher-resolution images from the spacecraft's Long Range Reconnaissance Imager (LORRI). http://photojournal.jpl.nasa.gov/catalog/PIA19953

  2. Statistics in review. Part 2: generalised linear models, time-to-event and time-series analysis, evidence synthesis and clinical trials.

    PubMed

    Moran, John L; Solomon, Patricia J

    2007-06-01

    In Part I, we reviewed graphical display and data summary, followed by a consideration of linear regression models. Generalised linear models, structured in terms of an exponential response distribution and link function, are now introduced, subsuming logistic and Poisson regression. Time-to-event ("survival") analysis is developed from basic principles of hazard rate, and survival, cumulative distribution and density functions. Semi-parametric (Cox) and parametric (accelerated failure time) regression models are contrasted. Time-series analysis is explicated in terms of trend, seasonal, and other cyclical and irregular components, and further illustrated by development of a classical Box-Jenkins ARMA (autoregressive moving average) model for monthly ICU-patient hospital mortality rates recorded over 11 years. Multilevel (random-effects) models and principles of meta-analysis are outlined, and the review concludes with a brief consideration of important statistical aspects of clinical trials: sample size determination, interim analysis and "early stopping".

  3. Use of portable FTIR spectrometers for detecting greenhouse gas emissions of the megacity Berlin - Part 2: Observed time series of XCO2 and XCH4

    NASA Astrophysics Data System (ADS)

    Hase, F.; Frey, M.; Blumenstock, T.; Groß, J.; Kiel, M.; Kohlhepp, R.; Mengistu Tsidu, G.; Schäfer, K.; Sha, M. K.; Orphal, J.

    2015-03-01

    Five portable Bruker EM27/SUN FTIR spectrometers have been used for the accurate and precise observation of column averaged abundances of CO2 and CH4 around the megacity Berlin. In the first part of this work (Frey et al., 2015) we have presented the various measures that were undertaken to ensure that the observations are consistent between sites, accurate and precise. Here, we present the recorded time series of XCH4 and XCO2 and demonstrate that the CO2 emissions of Berlin can be clearly identified in the observations. A simple dispersion model is applied which indicates a total strength of the Berlin source of about 0.8 t CO2 s-1. In the Supplement of this work, we provide the measured dataset and auxiliary data. We hope that the model community will exploit this unique dataset for state-of-the art inversion studies of CO2 and CH4 sources in the Berlin area.

  4. Overview of California's Efforts to Understand and Reduce Methane Sources

    NASA Astrophysics Data System (ADS)

    Croes, B. E.; Chen, Y.; Duren, R. M.; Falk, M.; Franco, G.; Herner, J.; Ingram, W.; Kuwayama, T.; McCarthy, R.; Scheehle, E.; Vijayan, A.

    2016-12-01

    Methane is an important short-lived climate pollutant (SLCP) and also has significant health implications as a tropospheric ozone precursor. As part of a comprehensive effort to reduce greenhouse gas (GHG) emissions overall by 40% from 1990 levels by 2030, California has proposed an SLCP Strategy that includes a 40% reduction of methane emissions from 2013 levels by 2030, with goals to reduce oil and gas related emissions and capture methane emissions from dairy operations and organic waste. A recent analysis of satellite data found a large methane "hot spot" over the Central Valley in California, likely the second largest over the entire U.S. In light of this finding, the California legislature passed Assembly Bill 1496 in 2015, which requires the California Air Resources Board (CARB) to undertake measurements to understand the sources of methane hot spots, evaluate life-cycle emissions from natural gas imported into California, and update relevant policies and programs. There is growing evidence in the recent scientific literature suggesting that a small fraction of methane sources within a category emit disproportionately higher emissions than their counterparts, usually referred to as "super emitters". As such, controlling these sources may provide a lower cost opportunity for methane reductions needed to meet near- and long-term climate goals. In order to achieve a comprehensive understanding of sources contributing to "hot spots", CARB, the California Energy Commission, and NASA's Jet Propulsion Laboratory are implementing a large-scale statewide methane survey using a tiered monitoring and measurement program, which will include airborne and ground-level measurements of the various regions and source sectors in the State. This presentation will discuss research and program implementation efforts to evaluate and mitigate methane super emitters and hot spots. These efforts are expected to improve our understanding of methane emission source distributions

  5. Part 1. Short-term effects of air pollution on mortality: results from a time-series analysis in Chennai, India.

    PubMed

    Balakrishnan, Kalpana; Ganguli, Bhaswati; Ghosh, Santu; Sankar, S; Thanasekaraan, Vijaylakshmi; Rayudu, V N; Caussy, Harry

    2011-03-01

    This report describes the results of a time-series analysis of the effect of short-term exposure to particulate matter with an aerodynamic diameter < or = 10 pm (PM10) on mortality in metropolitan Chennai, India (formerly Madras). This was one of three sites in India chosen by HEI as part of its Public Health and Air Pollution in Asia (PAPA) initiative. The study involved integration and analysis of retrospective data for the years 2002 through 2004. The data were obtained from relevant government agencies in charge of routine data collection. Data on meteorologic confounders (including temperature, relative humidity, and dew point) were available on all days of the study period. Data on mortality were also available on all days, but information on cause-of-death (including accidental deaths) could not be reliably ascertained. Hence, only all-cause daily mortality was used as the major outcome for the time-series analyses. Data on PM10, nitrogen dioxide (NO2), and sulfur dioxide (SO2) were limited to a much smaller number of days, but spanned the full study period. Data limitations resulting from low sensitivity of gaseous pollutant measurements led to using only PM10 in the main analysis. Of the eight operational ambient air quality monitor (AQM) stations in the city, seven met the selection criteria set forth in the common protocol developed for the three PAPA studies in India. In addition, all raw data used in the analysis were subjected to additional quality assurance (QA) and quality control (QC) criteria to ensure the validity of the measurements. Two salient features of the PM10 data set in Chennai were a high percentage of missing readings and a low correlation among daily data recorded by the AQMs. The latter resulted partly because each AQM had a small footprint (approximate area over which the air pollutant measurements recorded in the AQM are considered valid), and partly because of differences in source profiles among the 10 zones within the city. The

  6. Methane heat transfer investigation

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Future high chamber pressure LOX/hydrocarbon booster engines require copper base alloy main combustion chamber coolant channels similar to the SSME to provide adequate cooling and reusable engine life. Therefore, it is of vital importance to evaluate the heat transfer characteristics and coking thresholds for LNG (94% methane) cooling, with a copper base alloy material adjacent to he fuel coolant. High pressure methane cooling and coking characteristics recently evaluated at Rocketdyne using stainless steel heated tubes at methane bulk temperatures and coolant wall temperatures typical of advanced engine operation except at lower heat fluxes as limited by the tube material. As expected, there was no coking observed. However, coking evaluations need be conducted with a copper base surface exposed to the methane coolant at higher heat fluxes approaching those of future high chamber pressure engines.

  7. Methane heat transfer investigation

    NASA Technical Reports Server (NTRS)

    Cook, R. T.

    1984-01-01

    Future high chamber pressure LOX/hydrocarbon booster engines require copper-base alloy main combustion chamber coolant channels similar to the SSME to provide adequate cooling and resuable engine life. Therefore, it is of vital importance to evaluate the heat transfer characteristics and coking thresholds for LNG (94% methane) cooling, with a copper-base alloy material adjacent to the fuel coolant. High-pressure methane cooling and coking characteristics were recently evaluated using stainless-steel heated tubes at methane bulk temperatures and coolant wall temperatures typical of advanced engine operation except at lower heat fluxes as limited by the tube material. As expected, there was no coking observed. However, coking evaluations need be conducted with a copper-base surface exposed to the methane coolant at higher heat fluxes approaching those of future high chamber pressure engines.

  8. Enzymatic Oxidation of Methane

    SciTech Connect

    Sirajuddin, S; Rosenzweig, AC

    2015-04-14

    Methane monooxygenases (MMOs) are enzymes that catalyze the oxidation of methane to methanol in methanotrophic bacteria. As potential targets for new gas-to-liquid methane bioconversion processes, MMOs have attracted intense attention in recent years. There are two distinct types of MMO, a soluble, cytoplasmic MMO (sMMO) and a membrane-bound, particulate MMO (pMMO). Both oxidize methane at metal centers within a complex, multisubunit scaffold, but the structures, active sites, and chemical mechanisms are completely different. This Current Topic review article focuses on the overall architectures, active site structures, substrate reactivities, proteinprotein interactions, and chemical mechanisms of both MMOs, with an emphasis on fundamental aspects. In addition, recent advances, including new details of interactions between the sMMO components, characterization of sMMO intermediates, and progress toward understanding the pMMO metal centers are highlighted. The work summarized here provides a guide for those interested in exploiting MMOs for biotechnological applications.

  9. Multiparametric methane sensor for environmental monitoring

    NASA Astrophysics Data System (ADS)

    Borecki, M.; Duk, M.; Kociubiński, A.; Korwin-Pawlowski, M. L.

    2016-12-01

    Today, methane sensors find applications mostly in safety alarm installations, gas parameters detection and air pollution classification. Such sensors and sensors elements exists for industry and home use. Under development area of methane sensors application is dedicated to ground gases monitoring. Proper monitoring of soil gases requires reliable and maintenance-free semi-constant and longtime examination at relatively low cost of equipment. The sensors for soil monitoring have to work on soil probe. Therefore, sensor is exposed to environment conditions, as a wide range of temperatures and a full scale of humidity changes, as well as rain, snow and wind, that are not specified for classical methane sensors. Development of such sensor is presented in this paper. The presented sensor construction consists of five commercial non dispersive infra-red (NDIR) methane sensing units, a set of temperature and humidity sensing units, a gas chamber equipped with a micro-fan, automated gas valves and also a microcontroller that controls the measuring procedure. The electronics part of sensor was installed into customized 3D printed housing equipped with self-developed gas valves. The main development of proposed sensor is on the side of experimental evaluation of construction reliability and results of data processing included safety procedures and function for hardware error correction. Redundant methane sensor units are used providing measurement error correction as well as improved measurement accuracy. The humidity and temperature sensors are used for internal compensation of methane measurements as well as for cutting-off the sensor from the environment when the conditions exceed allowable parameters. Results obtained during environment sensing prove that the gas concentration readings are not sensitive to gas chamber vertical or horizontal position. It is important as vertical sensor installation on soil probe is simpler that horizontal one. Data acquired during six

  10. Methane drainage with horizontal boreholes in advance of longwall mining: an analysis. Final report

    SciTech Connect

    Gabello, D.P.; Felts, L.L.; Hayoz, F.P.

    1981-05-01

    The US Department of Energy (DOE) Morgantown Energy Technology Center has implemented a comprehensive program to demonstrate the technical and economic viability of coalbed methane as an energy resource. The program is directed toward solution of technical and institutional problems impeding the recovery and use of large quantities of methane contained in the nation's minable and unminable coalbeds. Conducted in direct support of the DOE Methane Recovery from Coalbeds Project, this study analyzes the economic aspects of a horizontal borehole methane recovery system integrated as part of a longwall mine operation. It establishes relationships between methane selling price and annual mine production, methane production rate, and the methane drainage system capital investment. Results are encouraging, indicating that an annual coal production increase of approximately eight percent would offset all associated drainage costs over the range of methane production rates and capital investments considered.

  11. Biostratigraphy and sedimentology of the Fluviatile Untere Serie (Early and Middle Miocene) in the central part of the North Alpine Foreland Basin: implications for palaeoenvironment and climate

    NASA Astrophysics Data System (ADS)

    Prieto, J.; Böhme, M.; Maurer, H.; Heissig, K.; Abdul Aziz, H.

    2009-10-01

    The Early to Middle Miocene Fluviatile Untere Serie lithostratigraphic unit of the Upper Freshwater Molasse (UFM) in the North Alpine Foreland Basin (NAFB) crops out in a 40 m long section at Untereichen-Altenstadt (central part of the NAFB). This section yields a unique superposition of two vertebrate assemblages belonging to different biostratigraphic units: early part OSM C + D (Karpatian) and OSM E (Early Badenian). Detailed taxonomic analyses reveal different diversity patterns in the two assemblages. Nine small mammal and six ectothermic vertebrate taxa occur in the older level UA 540 m, while 20 small mammal and 23 ectothermic vertebrate taxa are recorded for the younger level UA 565 m. From the latter locality comes a small-sized representative of the biostratigraphically significant Megacricetodon lappi lineage. This evolutionary level has not been documented previously for the eastern part of the NAFB. Bioclimatic analysis combined with lithofacies and architectural element analysis indicates that significant changes in the fluvial sedimentation style, surface-water runoff and tectonics occurred between the Early Karpatian and Early Badenian. A meandering fluvial system (marly unit) is erosively overlain by sandy braided river deposits (sandy unit). Overbank deposits of the marly unit revealed that the older vertebrate fossil assemblage (UA 540 m) is deposited in an animal burrow that was presumably produced by owls. Both reptilian and mammalian taxa are indicative of a relatively open environment and dry, probably semi-arid climate. Conversely, vertebrates from the sandy unit (UA 565 m), which are accumulated in channel fill deposits, suggest closed as well as open habitats with a subtropical humid climate and mean annual rainfall of about 1,000 mm. According to the sequence stratigraphic analysis the marly unit is interpreted as a highstand-system-tract of the TB 2.2 global 3rd order sequence. The new results add support to the hypothesis that the

  12. Electrochemical methane sensor

    DOEpatents

    Zaromb, S.; Otagawa, T.; Stetter, J.R.

    1984-08-27

    A method and instrument including an electrochemical cell for the detection and measurement of methane in a gas by the oxidation of methane electrochemically at a working electrode in a nonaqueous electrolyte at a voltage about 1.4 volts vs R.H.E. (the reversible hydrogen electrode potential in the same electrolyte), and the measurement of the electrical signal resulting from the electrochemical oxidation.

  13. Laser beam methane detector

    NASA Technical Reports Server (NTRS)

    Hinkley, E. D., Jr.

    1981-01-01

    Instrument uses infrared absorption to determine methane concentration in liquid natural gas vapor. Two sensors measure intensity of 3.39 mm laser beam after it passes through gas; absorption is proportional to concentration of methane. Instrument is used in modeling spread of LNG clouds and as leak detector on LNG carriers and installations. Unit includes wheels for mobility and is both vertically and horizontally operable.

  14. Climate change and wildfire influence the methane uptake capacity in Australian eucalypt forest soils

    NASA Astrophysics Data System (ADS)

    Arndt, Stefan; Fest, Benedikt; Hinko-Najera, Nina; Wardlaw, Tim; Livesley, Stephen

    2014-05-01

    Forest ecosystems comprise the largest soil sink for the greenhouse gas methane and climate change and fire can have significant impacts on this important process. We present data from a number of long-term field studies that investigated the impacts of reduced rainfall and fire regimes on soil methane flux in Australian forest systems. Long term soil methane flux measurements with automated chambers indicated that around 90% of soil methane uptake variability in dry- and wet-sclerophyll Eucalyptus obliqua (L. Her.) forests was explained by soil moisture through influencing methane diffusivity. The application of rainfall reduction shelters in the dry-sclerophyll eucalypt forest caused an average reduction of 14.6% in soil volumetric water content but an increase in soil methane uptake of around 38%, again a consequence of increased methane diffusivity. Consequently, the potential reductions in rainfall in large parts of Australia are likely to result in an increase in methane uptake. Wildfire disturbance also altered forest soil methane uptake and here the methane uptake capacity was related to stand age dependent changes in stand structure likely linked to changes in stand water use. Stands that had dryer soils displayed greater methane uptake, indicating that soil methane uptake changes during forest stand development. Wildfire can therefore have significant impacts on landscape level methane uptake.

  15. Two Faculties or One? The Conundrum of Part-Timers in a Bifurcated Work Force. New Pathways: Faculty Career and Employment for the 21st Century Working Paper Series, Inquiry #6.

    ERIC Educational Resources Information Center

    Gappa, Judith M.; Leslie, David W.

    This paper, one in a series about the priorities of the professoriate, traces the rise in the use of part-time faculty and asks whether academic employment has become a dual labor market. Data for the study was derived from the 1993 National Study of Postsecondary Faculty. The research focuses on the effects on part-time faculty and on educational…

  16. Methane Emissions from Upland Forests

    NASA Astrophysics Data System (ADS)

    Megonigal, Patrick; Pitz, Scott; Wang, Zhi-Ping

    2016-04-01

    Global budgets ascribe 4-10% of atmospheric methane sinks to upland soils and assume that soils are the sole surface for methane exchange between upland forests and the atmosphere. The dogma that upland forests are uniformly atmospheric methane sinks was challenged a decade ago by the discovery of abiotic methane production from plant tissue. Subsequently a variety of relatively cryptic microbial and non-microbial methane sources have been proposed that have the potential to emit methane in upland forests. Despite the accumulating evidence of potential methane sources, there are few data demonstrating actual emissions of methane from a plant surface in an upland forest. We report direct observations of methane emissions from upland tree stems in two temperate forests. Stem methane emissions were observed from several tree species that dominate a forest located on the mid-Atlantic coast of North America (Maryland, USA). Stem emissions occurred throughout the growing season while soils adjacent to the trees simultaneously consumed methane. Scaling fluxes by stem surface area suggested the forest was a net methane source during a wet period in June, and that stem emissions offset 5% of the soil methane sink on an annual basis. High frequency measurements revealed diurnal cycles in stem methane emission rates, pointing to soils as the methane source and transpiration as the most likely pathway for gas transport. Similar observations were made in an upland forest in Beijing, China. However, in this case the evidence suggested the methane was not produced in soils, but in the heartwood by microbial or non-microbial processes. These data challenge the concept that forests are uniform sinks of methane, and suggest that upland forests are smaller methane sinks than previously estimated due to stem emissions. Tree emissions may be particularly important in upland tropical forests characterized by high rainfall and transpiration.

  17. A CLINICAL GUIDE TO THE ASSESSMENT AND TREATMENT OF BREATHING PATTERN DISORDERS IN THE PHYSICALLY ACTIVE: PART 2, A CASE SERIES

    PubMed Central

    Chapman, Erin B.; Nasypany, Alan; Baker, Russell T.; May, Jim

    2016-01-01

    Introduction Breathing pattern disorders (BPDs) are characterized by persistent, suboptimal breathing strategies that may result in additional musculoskeletal pain and/or dysfunction. The purpose of this case series was to examine the effects of Primal Reflex Release Technique (PRRT) and breathing exercise interventions in physically active individuals that presented with a primary complaint of musculoskeletal pain, a BPD, and startle reflexes. Subjects The assessment techniques described in Part 1 of this series were used to identify three student athletes (aged 16-22) who presented with musculoskeletal pain of the low back, mid back, and knee, BPDs, and startle reflexes. The subjects were unable to identify an apparent source of their pain. Intervention The clinician's classification of the subject's breathing patterns guided intervention(s). Each subject was treated once with PRRT and/or a breathing reflex triggering exercise. Results Each of the three subjects demonstrated clinically important improvements on the numerical pain rating scale specific to their tender areas and/or with their primary musculoskeletal complaint. Discussion These findings suggest that it may be useful to assess for a BPD and startle reflexes along with a standard orthopedic evaluation in the physically active athlete. Treatment of BPD's may positively impact musculoskeletal pain and/or dysfunction. Further research is needed to understand the effects of treatment of BPD's and how these effects relate to musculoskeletal dysfunction. Summary The prevalence of BPD with startle reflexes is unknown and implications regarding the assessment for and treatment of BPD has limited research; however, positive results were demonstrated for the three subjects after normalizing breathing patterns. Level of Evidence 4 PMID:27904799

  18. The Impact of Methane Clathrate Emissions on the Earth System

    NASA Astrophysics Data System (ADS)

    Cameron-Smith, P. J.; Bhattacharyya, S.; Bergmann, D. J.; Reagan, M. T.; Elliott, S.; Moridis, G. J.

    2013-12-01

    Methane is locked in ice-like deposits called clathrates in ocean sediments and underneath permafrost regions. Clathrates are stable under high pressures and low temperatures, so in a warming climate, increases in ocean temperatures could lead to dissociation of the clathrates and release methane into the ocean and subsequently the atmosphere, where methane is both an important greenhouse gas and a key species in atmospheric chemistry. Clathrates in the shallower parts of the Arctic Ocean (around 300m depth) are predicted to be particularly important since clathrates at that depth are expected to start outgassing abruptly in the next few decades. We will present the atmospheric impact of such methane emissions using multi-century steady-state simulations with a version of the Community Earth System Model (CESM) that includes atmospheric chemistry. Our simulations include a plausible release from clathrates in the Arctic that increases global methane emissions above present-day conditions by 22%, as well as a scenario with 10 times those clathrate emissions. The CESM model includes a fully interactive physical ocean, to which we added a fast atmospheric chemistry mechanism that represents methane as a fully interactive tracer (with emissions rather than concentration boundary conditions). The results indicate that such Arctic clathrate emissions (1) increase global methane concentrations by an average of 38%, non-uniformly; (2) increase surface ozone concentrations by around 10% globally, and even more in polluted regions; (3) increase methane lifetime by 13%; (4) increase the interannual variability in surface methane, surface ozone, and methane lifetime, and (5) show modest differences in surface temperature and methane lifetime compared to simulations in which the clathrate emissions are distributed uniformly. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  19. Tablet splitting: a review of the clinical and economic outcomes and patient acceptance. Second of a 2-part series. Part 1 was published in May 2012 (Consult Pharm 2012;27:239-53).

    PubMed

    Freeman, Maisha Kelly; White, Whitney; Iranikhah, Maryam

    2012-06-01

    To describe the clinical outcomes, patient acceptance, and economic effect associated with tablet splitting. PubMed (1966-June 2011) and International Pharmaceutical Abstract (1975-June 2011) searches were conducted using tablet splitting as the search terms. All studies that evaluated the clinical outcome (n = 4), patient acceptance (n = 5), and economic effects (n = 8) of tablet splitting were included. The American Pharmacists Association guidelines, recommendations from the Food and Drug Administration, and clinical trial data were evaluated. The majority of trials conducted evaluating clinical outcomes associated with tablet splitting were evaluated in patients receiving statins and antihypertensives. Clinical outcomes associated with risperidone were assessed. No adverse clinical outcomes were observed with therapy. Most studies evaluating the economic effects of tablet splitting have revealed a cost savings associated with this process; however, many studies were subject to limitations. The first part of this two-part series reviewed the weight and content uniformity in tablet splitting. Tablet splitting does not seem to significantly affect clinical outcomes related to management of hypertension, cholesterol, or psychiatric disorders, nor influence overall patient adherence.

  20. Sea-floor methane blow-out and global firestorm at the K-T boundary

    USGS Publications Warehouse

    Max, M.D.; Dillon, William P.; Nishimura, C.; Hurdle, B.G.

    1999-01-01

    A previously unsuspected source of fuel for the global firestorm recorded by soot in the Cretaceous-Tertiary impact layer may have resided in methane gas associated with gas hydrate in the end-Cretaceous seafloor. End-Cretaceous impact-generated shock and megawaves would have had the potential to initiate worldwide oceanic methane gas blow-outs from these deposits. The methane would likely have ignited and incompletely combusted. This large burst of methane would have been followed by longer-term methane release as a part of a positive thermal feedback in the disturbed ocean-atmosphere system.

  1. Eddy covariance based methane flux in Sundarbans mangroves, India

    NASA Astrophysics Data System (ADS)

    Jha, Chandra Shekhar; Rodda, Suraj Reddy; Thumaty, Kiran Chand; Raha, A. K.; Dadhwal, V. K.

    2014-06-01

    We report the initial results of the methane flux measured using eddy covariance method during summer months from the world's largest mangrove ecosystem, Sundarbans of India. Mangrove ecosystems are known sources for methane (CH4) having very high global warming potential. In order to quantify the methane flux in mangroves, an eddy covariance flux tower was recently erected in the largest unpolluted and undisturbed mangrove ecosystem in Sundarbans (India). The tower is equipped with eddy covariance flux tower instruments to continuously measure methane fluxes besides the mass and energy fluxes. This paper presents the preliminary results of methane flux variations during summer months (i.e., April and May 2012) in Sundarbans mangrove ecosystem. The mean concentrations of CH4 emission over the study period was 1682 ± 956 ppb. The measured CH4 fluxes computed from eddy covariance technique showed that the study area acts as a net source for CH4 with daily mean flux of 150.22 ± 248.87 mg m-2 day-1. The methane emission as well as its flux showed very high variability diurnally. Though the environmental conditions controlling methane emission is not yet fully understood, an attempt has been made in the present study to analyse the relationships of methane efflux with tidal activity. This present study is part of Indian Space Research Organisation-Geosphere Biosphere Program (ISRO-GBP) initiative under `National Carbon Project'.

  2. Methane concentrations and oxidation in nearshore waters of the Lena River Delta

    NASA Astrophysics Data System (ADS)

    Joye, S. B.; Samarkin, V.; Shakhova, N. E.; Semiletov, I. P.

    2014-12-01

    The Arctic is warming dramatically, with potentially catastrophic impacts on climate change through rapid mobilization of labile carbon reservoirs sequestered presently in permafrost. Increasingly, Arctic feedbacks are recognized as key contributors to climate change, including cycles associated with the powerful greenhouse gas methane, whose atmospheric concentration has more than doubled since the pre-industrial epoch. Sustained methane release to the atmosphere from thawing Arctic permafrost and delivery to the coastal ocean through groundwater or riverine discharge or expulsion from the seabed is a positive and likely highly significant feedback to climate warming. Microbially-mediated methane oxidation provides a key sink and effective biofilter that can limit methane fluxes from coastal environments to the atmosphere. We examined methane dynamics on the East Siberian Arctic Shelf by determining concentrations and oxidation rates at a series of stations near the Lena River Delta and moving offshore. Methane concentrations and oxidation rates were highly elevated in and near the river mouth compared to offshore waters, except when the offshore waters were impacted by seabed methane seepage. The regulation of methane oxidation in Arctic waters appears two-fold: first, rates are strongly related to methane availability and second, in the presence of methane, nutrient availability strongly regulates methane consumption. Along the Lena river delta, elevated concentrations of both nutrients and methane create ideal conditions to support high rates of pelagic methanotrophy. Offshore, where nutrient concentrations are lower and more limiting, methane oxidation rates are considerably lower. These data suggest that, at present, nearshore waters are fairly efficient methane sinks while in offshore waters, pelagic methanotrophy is inefficient, allowing methane to escape to the atmosphere.

  3. 13CH3D kinetic isotope effects for methane oxidation by OH - predicting the "clumped" isotopic signature of atmospheric methane

    NASA Astrophysics Data System (ADS)

    Whitehill, A. R.; Joelsson, L. M. T.; Wang, D. T.; Johnson, M. S.; Ono, S.

    2015-12-01

    Methane is a significant long-lived greenhouse gas, but the tropospheric methane budget is not entirely constrained. "Clumped" isotopologues of methane, including 13CH3D, can provide additional constraints on the atmospheric methane cycle. Interpretation of these novel isotope tracers requires an understanding of the "clumped" isotopic signature of various methane sources, as well as the kinetic isotope effects of the methane sink reactions. We performed a series of photochemical experiments to measure the isotopic fractionation during the CH4+OH reaction. Experiments were carried out in a 100 L quartz photochemical reactor. Photolysis of ozone (O3) in the presence of water (H2O) was used to produce OH radicals. Experiments were performed in a helium bath gas. Fourier transform infrared spectroscopy (FTIR) was used to monitor reaction progress. At various intervals during the reaction, methane was sampled from the cell and analyzed for isotope ratios by tunable infrared laser direct absorption spectroscopy (TILDAS). By simultaneously measuring four different isotopologues of methane (12CH4,12CH3D, 13CH4, 13CH3D), we were able to constrain the kinetic isotope effects for 12CH3D, 13CH4, and the doubly-substitued isotopologue 13CH3D. These results are combined with published clumped isotope data from different methane sources to model the Δ13CH3D (i.e. deviation from "stochastic" distribution of isotopes) of tropospheric methane and its sensitivity to different sources. The Δ13CH3D value of tropospheric methane does not strongly depend upon isotope fractionation during the OH sink reaction. Rather, the Δ13CH3D value of tropospheric methane reflects a mixing of different source signatures. Due to nonlinearity in mixing of Δ13CH3D, the Δ13CH3D value of tropospheric methane will be larger than the weighted average of the Δ13CH3D value of the sources. A first order interpretation of variations in the Δ13CH3D value of tropospheric methane is that it reflects changes

  4. Combustion of Methane Hydrate

    NASA Astrophysics Data System (ADS)

    Roshandell, Melika

    A significant methane storehouse is in the form of methane hydrates on the sea floor and in the arctic permafrost. Methane hydrates are ice-like structures composed of water cages housing a guest methane molecule. This caged methane represents a resource of energy and a potential source of strong greenhouse gas. Most research related to methane hydrates has been focused on their formation and dissociation because they can form solid plugs that complicate transport of oil and gas in pipelines. This dissertation explores the direct burning of these methane hydrates where heat from the combustion process dissociates the hydrate into water and methane, and the released methane fuels the methane/air diffusion flame heat source. In contrast to the pipeline applications, very little research has been done on the combustion and burning characteristics of methane hydrates. This is the first dissertation on this subject. In this study, energy release and combustion characteristics of methane hydrates were investigated both theoretically and experimentally. The experimental study involved collaboration with another research group, particularly in the creation of methane hydrate samples. The experiments were difficult because hydrates form at high pressure within a narrow temperature range. The process can be slow and the resulting hydrate can have somewhat variable properties (e.g., extent of clathration, shape, compactness). The experimental study examined broad characteristics of hydrate combustion, including flame appearance, burning time, conditions leading to flame extinguishment, the amount of hydrate water melted versus evaporated, and flame temperature. These properties were observed for samples of different physical size. Hydrate formation is a very slow process with pure water and methane. The addition of small amounts of surfactant increased substantially the hydrate formation rate. The effects of surfactant on burning characteristics were also studied. One finding

  5. Methane Emissions From Boreal and Tropical Forest Ecosystems

    NASA Astrophysics Data System (ADS)

    Williams, J.; Sinha, V.; Crutzen, P.; Lelieveld, J.

    2006-12-01

    Methane is a climatologically important greenhouse gas and plays a key role in regulating water vapour in the stratosphere and hydroxyl radicals in the troposphere. Recent findings that vegetation emits methane have stimulated efforts to ascertain the impact of this source on the global budget of this trace gas. In this work, we present the results of high frequency (1 minute) methane measurements conducted in the boreal forests of Finland and the tropical forests of Suriname, in April-May, 2005 and October 2005 respectively. The measurements were performed using a gas chromatograph - flame ionization detector (GC-FID). The average of the median mixing ratios during a typical diel cycle were 1.83 μmol mol-1 and 1.74 μmol mol-1 for the boreal forest ecosystem and tropical forest ecosystem respectively, with remarkable similarity in the time series of both the boreal and tropical diel profiles. Night time methane emission flux of the boreal forest ecosystem, calculated from the increase of methane during the night and measured nocturnal boundary layer heights yields a flux of 3.62 x 1011 molecules cm-2 s-1.These results highlight the importance of the boreal and tropical forest ecosystems for the global budget of methane. We also discuss our results in the context of recent work reporting high methane mixing ratios over tropical forests using space borne near infra red spectroscopy measurements.

  6. Reactor models for a series of continuous stirred tank reactors with a gas-liquid-solid leaching system: Part I. Surface reaction control

    NASA Astrophysics Data System (ADS)

    Papangelakis, V. G.; Demopoulos, G. P.

    1992-12-01

    In this three-part series of articles, comprehensive three-phase steady-state hydrometallurgical reactor models of the continuous stirred tank reactor (CSTR) type are developed and applied to a commercial (pressure oxidation) process. The key features of the developed models are the coupling of both mass and heat balance equations, the description of the nonisothermal performance (autothermal) of a multistage continuous reactor, and the treatment of multimineral feed materials. The model considers only the oxidation reactions, because they mainly affect the thermal balance of the reactor. The stoichiometries and intrinsic kinetics of the heterogeneous leaching reactions, which are established via independent experiments, are the foundation of the developed model. A three-phase (g-l-s) reaction process might be controlled by either surface reaction control, i.e., the rate(s) of the heterogeneous leaching reaction(s), or by gas transfer control, i.e., the rate of transfer of the gaseous reactant into the liquid phase. In the present article (Part I), the case of surface reaction control is treated. The article addresses, in particular, the following topics: (1) it outlines the basic mass and heat balance equations which describe the performance of a multistage leaching reactor; (2) it presents a continuous function to describe the particle size distribution of the feed; and (3) it develops, on the basis of probability theory, number- and mass-particle size density functions which give the size distribution of particle populations reacting according to the surface reaction control-shrinking core model.

  7. The basics of coalbed methane

    SciTech Connect

    2006-12-15

    The report is an overview of coalbed methane (CBM), also known as coal seam gas. It provides an overview of what coalbed methane is and the current status of global coalbed methane exploration and production. Topics covered in the report include: An analysis of the natural gas industry, including current and future production, consumption, and reserves; A detailed description of coalbed methane, its characteristics, and future potential; An analysis of the key business factors that are driving the increased interest in coalbed methane; An analysis of the barriers that are hindering the development of coalbed methane; An overview of the technologies used for coalbed methane production and water treatment; and Profiles of key coalbed methane producing countries. 25 figs., 5 tabs., 1 app.

  8. Possible Methane Sources and Sinks

    NASA Image and Video Library

    2014-12-16

    This illustration portrays possible ways methane might be added to Mars atmosphere sources and removed from the atmosphere sinks. NASA Curiosity Mars rover has detected fluctuations in methane concentration in the atmosphere.

  9. Leaking methane reservoirs offshore Svalbard

    NASA Astrophysics Data System (ADS)

    Minshull, T. A.; Westbrook, G. K.; Weitemeyer, K. A.; Sinha, M. C.; Goswami, B. K.; Marsset, B.

    2012-10-01

    Methane hydrate—a solid substance in which methane is trapped within ice-like crystals—is stable at low temperatures and high pressures and may be destabilized by ocean warming on both geological and human time scales. Methane is a powerful greenhouse gas, and methane released from hydrate provides a potential positive feedback mechanism in global climate change [e.g., Archer and Buffett, 2005]—in theory, the more methane is released by the hydrates, the warmer the climate gets, causing the ocean to warm and release more methane. However, methane escaping from the seabed is oxidized and dissolved in the ocean, and insufficient methane may reach the atmosphere to affect the climate significantly. Its importance for climate change therefore depends on whether the flux from the seabed is great enough to overcome solution in the ocean and perturb atmospheric concentrations over sufficiently long time scales.

  10. Environmental control on aerobic methane oxidation in coastal waters

    NASA Astrophysics Data System (ADS)

    Steinle, Lea; Maltby, Johanna; Engbersen, Nadine; Zopfi, Jakob; Bange, Hermann; Elvert, Marcus; Hinrichs, Kai-Uwe; Kock, Annette; Lehmann, Moritz; Treude, Tina; Niemann, Helge

    2016-04-01

    Large quantities of methane are produced in anoxic sediments of continental margins and may be liberated to the overlying water column, where some of it is consumed by aerobic methane oxidizing bacteria (MOB). Aerobic methane oxidation (MOx) in the water column is consequently the final sink for methane before its release to the atmosphere, where it acts as a potent greenhouse gas. In the context of the ocean's contribution to atmospheric methane, coastal seas are particularly important accounting >75% of global methane emission from marine systems. Coastal oceans are highly dynamic, in particular with regard to the variability of methane and oxygen concentrations as well as temperature and salinity, all of which are potential key environmental factors controlling MOx. To determine important environmental controls on the activity of MOBs in coastal seas, we conducted a two-year time-series study with measurements of physicochemical water column parameters, MOx activity and the composition of the MOB community in a coastal inlet in the Baltic Sea (Boknis Eck Time Series Station, Eckernförde Bay - E-Bay). In addition, we investigated the influence of temperature and oxygen on MOx during controlled laboratory experiments. In E-Bay, hypoxia developed in bottom waters towards the end of the stratification period. Constant methane liberation from sediments resulted in bottom water methane accumulations and supersaturation (with respect to the atmospheric equilibrium) in surface waters. Here, we will discuss the factors impacting MOx the most, which were (i) perturbations of the water column (ii) temperature and (iii) oxygen concentration. (i) Perturbations of the water column caused by storm events or seasonal mixing led to a decrease in MOx, probably caused by replacement of stagnant water with a high standing stock of MOB by 'new' waters with a lower abundance of methanotrophs. b) An increase in temperature generally led to higher MOx rates. c) Even though methane was

  11. Transformations in methane hydrates

    USGS Publications Warehouse

    Chou, I.-Ming; Sharma, A.; Burruss, R.C.; Shu, J.; Mao, Ho-kwang; Hemley, R.J.; Goncharov, A.F.; Stern, L.A.; Kirby, S.H.

    2000-01-01

    Detailed study of pure methane hydrate in a diamond cell with in situ optical, Raman, and x-ray microprobe techniques reveals two previously unknown structures, structure II and structure H, at high pressures. The structure II methane hydrate at 250 MPa has a cubic unit cell of a = 17.158(2) A?? and volume V = 5051.3(13) A??3; structure H at 600 MPa has a hexagonal unit cell of a = 11.980(2) A??, c = 9.992(3) A??, and V = 1241.9(5) A??3. The compositions of these two investigated phases are still not known. With the effects of pressure and the presence of other gases in the structure, the structure II phase is likely to dominate over the known structure I methane hydrate within deep hydrate-bearing sediments underlying continental margins.

  12. Catalytic aromatization of methane.

    PubMed

    Spivey, James J; Hutchings, Graham

    2014-02-07

    Recent developments in natural gas production technology have led to lower prices for methane and renewed interest in converting methane to higher value products. Processes such as those based on syngas from methane reforming are being investigated. Another option is methane aromatization, which produces benzene and hydrogen: 6CH4(g) → C6H6(g) + 9H2(g) ΔG°(r) = +433 kJ mol(-1) ΔH°(r) = +531 kJ mol(-1). Thermodynamic calculations for this reaction show that benzene formation is insignificant below ∼600 °C, and that the formation of solid carbon [C(s)] is thermodynamically favored at temperatures above ∼300 °C. Benzene formation is insignificant at all temperatures up to 1000 °C when C(s) is included in the calculation of equilibrium composition. Interestingly, the thermodynamic limitation on benzene formation can be minimized by the addition of alkanes/alkenes to the methane feed. By far the most widely studied catalysts for this reaction are Mo/HZSM-5 and Mo/MCM-22. Benzene selectivities are generally between 60 and 80% at methane conversions of ∼10%, corresponding to net benzene yields of less than 10%. Major byproducts include lower molecular weight hydrocarbons and higher molecular weight substituted aromatics. However, carbon formation is inevitable, but the experimental findings show this can be kinetically limited by the use of H2 or oxidants in the feed, including CO2 or steam. A number of reactor configurations involving regeneration of the carbon-containing catalyst have been developed with the goal of minimizing the cost of regeneration of the catalyst once deactivated by carbon deposition. In this tutorial review we discuss the thermodynamics of this process, the catalysts used and the potential reactor configurations that can be applied.

  13. Phytoremediation of Atmospheric Methane

    DTIC Science & Technology

    2013-04-15

    bacterial genes for the three subunit proteins of the soluble methane monooxygenase and with two associated genes, the mmoG and the mmoC. The...plant, Arabidopsis thaliana, with the bacterial genes for the three subunit proteins of the soluble methane monooxygenase and with two associated genes...transcription and activity, perhaps as a chaperone.  Here we report that we have transformed a plant, Arabidopsis thaliana, with the  bacterial  genes for the

  14. Methane-Powered Airplane

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Beech Aircraft's Corporation's Boulder Division developed expertise in producing superinsulated virtually leak-proof cryogenic equipment for storing liquid oxygen and hydrogen fuels in NASA's Apollo, Skylab and Space Shuttle programs. Boulder Division used this experience in designing a fuel storage tank for liquid methane, a "cryogenic" fuel that must be supercooled to keep it liquid. Beech Aircraft is producing a four-place lightplane powered by liquid methane (LM) which is stored in two of these specially designed cryogenic storage tanks holding 18 gallons each.

  15. Clumped isotope effects during OH and Cl oxidation of methane

    NASA Astrophysics Data System (ADS)

    Whitehill, Andrew R.; Joelsson, Lars Magnus T.; Schmidt, Johan A.; Wang, David T.; Johnson, Matthew S.; Ono, Shuhei

    2017-01-01

    A series of experiments were carried out to determine the clumped (13CH3D) methane kinetic isotope effects during oxidation of methane by OH and Cl radicals, the major sink reactions for atmospheric methane. Experiments were performed in a 100 L quartz photochemical reactor, in which OH was produced from the reaction of O(1D) (from O3 photolysis) with H2O, and Cl was from photolysis of Cl2. Samples were taken from the reaction cell and analyzed for methane (12CH4, 12CH3D, 13CH4, 13CH3D) isotopologue ratios using tunable infrared laser direct absorption spectroscopy. Measured kinetic isotope effects for singly substituted species were consistent with previous experimental studies. For doubly substituted methane, 13CH3D, the observed kinetic isotope effects closely follow the product of the kinetic isotope effects for the 13C and deuterium substituted species (i.e., 13,2KIE = 13KIE × 2KIE). The deviation from this relationship is 0.3‰ ± 1.2‰ and 3.5‰ ± 0.7‰ for OH and Cl oxidation, respectively. This is consistent with model calculations performed using quantum chemistry and transition state theory. The OH and Cl reactions enrich the residual methane in the clumped isotopologue in open system reactions. In a closed system, however, this effect is overtaken by the large D/H isotope effect, which causes the residual methane to become anti-clumped relative to the initial methane. Based on these results, we demonstrate that oxidation of methane by OH, the predominant oxidant for tropospheric methane, will only have a minor (∼0.3‰) impact on the clumped isotope signature (Δ13CH3D, measured as a deviation from a stochastic distribution of isotopes) of tropospheric methane. This paper shows that Δ13CH3D will provide constraints on methane source strengths, and predicts that Δ12CH2D2 can provide information on methane sink strengths.

  16. Perspectives On The Global Budget of Methane

    NASA Astrophysics Data System (ADS)

    Khalil, M. K.; Butenhoff, C. L.; Shearer, M. J.

    2008-12-01

    Early budgets of methane focused on the emissions from individual sources but the estimates had large uncertainties. These uncertainties have been reduced considerably in recent years, but we need an understanding of the trends in the sources as well as their spatial distributions if we are to use methane to control global warming. A nearly 30 year long time series of global atmospheric methane concentrations has accumulated that can provide some of the answers. One of the most dramatic findings is that the increase of methane has nearly stopped in the last decade. But the record also shows that the trend was falling ever since systematic measurements were taken, and perhaps even before that. This finding has led to some puzzles. There is a belief that the anthropogenic sources of methane are increasing but to explain the falling trend we need decreasing sources (or increasing sinks). In fact, the atmospheric measurements show only that the most probable explanation for the decreasing trend and the present near constancy of concentrations is that the global source of methane has been more or less constant over the last 30 years with many short-term ups and downs. Moreover, there is good evidence that some of the major man-made sources of methane, such as cattle, biomass burning and possibly others, have stopped increasing some time back and other sources such as rice agriculture may have decreased over the last 30 years. This allows some smaller energy based sources to have increased, consistent with expectations, and balance out the decreasing sources to keep the total more or less constant. A credible quantitative case can be made for a stable global source based on available information on the trends of the various sources and sinks of methane, but uncertainties remain. We will argue that the stability of sources and sinks is the most likely explanation of the methane concentration trends. We will use this result to re-evaluate the future of man- made methane

  17. Methane in Crystalline Bedrock: the Outokumpu Deep Drill Hole, Finland

    NASA Astrophysics Data System (ADS)

    Kietäväinen, R.; Ahonen, L.; Niinikoski, P.; Itävaara, M.; Kukkonen, I. T.

    2014-12-01

    Carbon is a key element for life. One of the most interesting forms of carbon is methane, as it is both consumed and produced by microorganisms. Methane has also several possible ways of abiotic origin, some of which could provide understanding of the origin of life itself. The study of methane is thus important in order to understand deep subsurface ecosystems such as those found in the 2516 m deep Outokumpu Deep Drill Hole within the Precambrian Fennoscandian Shield in eastern Finland. There rock types differ from graphite-bearing mica schist and black schist to serpentinite and pegmatitic granodiorite and saline, gas-rich water, with up to 32 mmol l-1 of methane, and residence times of tens of millions of years occupies the fracture zones which host diverse microbial life, including methanogenic archaea. In order to understand methane systematics in crystalline bedrock, we analysed several forms of carbon, including dissolved inorganic carbon (DIC), methane and ethane from the Outokumpu Deep Drill Hole for their isotopic composition. In addition, isotopic compositions of water and hydrogen were determined. The results show that hydrogen is in isotopic equilibrium in the system H2O-H2-CH4 at ambient temperatures, which could either indicate equilibration due to long residence time or relatively recent production of methane in situ. Therefore hydrogen is not a very useful indicator for the origin of methane in this case. Carbon isotope analysis shows that both methane and DIC becomes generally more enriched in 13C with depth, which could indicate higher amounts of microbial methane in the upper part of the bedrock. Based on carbon isotope composition, two types of ethane can be discerned. Taken all the evidence together, this leads us to suggest that at least two mechanisms are responsible for the methane production in Outokumpu: 1) Biotic which comprise most of methane and 2) abiotic which dominates in the deeper parts of the bedrock. The former type may include

  18. Marshall Tests 3D-Printed, Methane-Powered Turbopump

    NASA Image and Video Library

    2016-04-21

    This video shows a test with at 3-D printed turbopump made with 45 percent fewer parts than traditionally manufactured rocket fuel pumps. The pump’s turbine spins at more than 36,000 revolutions per minute. As the turbopump moves 600 gallons of liquid methane per minute, frost forms on the outside because the fuel is super-cooled to -255 degrees Fahrenheit. Methane burns out the flame pipe at the end of the test area.

  19. Methane emissions from natural wetlands

    SciTech Connect

    Meyer, J.L.; Burke, R.A. Jr.

    1993-09-01

    Analyses of air trapped in polar ice cores in conjunction with recent atmospheric measurements, indicate that the atmospheric methane concentration increased by about 250% during the past two or three hundred years (Rasmussen and Khalil, 1984). Because methane is a potent ``greenhouse`` gas, the increasing concentrations are expected to contribute to global warning (Dickinson and Cicerone, 1986). The timing of the methane increase suggests that it is related to the rapid growth of the human population and associated industrialization and agricultural development. The specific causes of the atmospheric methane concentration increase are not well known, but may relate to either increases in methane sources, decreases in the strengths of the sinks, or both.

  20. Methane Clathrate Hydrate Prospecting

    NASA Technical Reports Server (NTRS)

    Duxbury, N.; Romanovsky, V.

    2003-01-01

    A method of prospecting for methane has been devised. The impetus for this method lies in the abundance of CH4 and the growing shortages of other fuels. The method is intended especially to enable identification of subpermafrost locations where significant amounts of methane are trapped in the form of methane gas hydrate (CH4(raised dot)6H2O). It has been estimated by the U.S. Geological Survey that the total CH4 resource in CH4(raised dot) 6H2O exceeds the energy content of all other fossil fuels (oil, coal, and natural gas from non-hydrate sources). Also, CH4(raised dot)6H2O is among the cleanest-burning fuels, and CH4 is the most efficient fuel because the carbon in CH4 is in its most reduced state. The method involves looking for a proxy for methane gas hydrate, by means of the combination of a thermal-analysis submethod and a field submethod that does not involve drilling. The absence of drilling makes this method easier and less expensive, in comparison with prior methods of prospecting for oil and natural gas. The proposed method would include thermoprospecting in combination with one more of the other non-drilling measurement techniques, which could include magneto-telluric sounding and/or a subsurface-electrical-resistivity technique. The method would exploit the fact that the electrical conductivity in the underlying thawed region is greater than that in the overlying permafrost.

  1. Saturn Methane Image

    NASA Image and Video Library

    2004-03-05

    NASA's Cassini narrow angle camera took this image of Saturn on Feb. 16, 2004, from a distance of 66.1 million kilometers (41.1 million miles) in a special filter which reveals clouds and haze high in the atmosphere. The image scale is 397 kilometers (247 miles) per pixel. The MT2 spectral filter samples a near-infrared region of the electromagnetic spectrum where methane gas absorbs light at a wavelength of 727 nanometers. In the image, methane gas is uniformly mixed with hydrogen, the main gas in Saturn's atmosphere. Dark locales are places of strong methane absorption, relatively free of high clouds; the bright areas are places with high, thick clouds which shield the methane below. Image details reveal a high, thick equatorial cloud and a relatively deep or thin haze encircling the pole, as well as several distinct latitude bands with different cloud height attributes. It also shows a high atmospheric disturbance, just south of the equator, which has persisted throughout the 1990s in images returned by NASA's Hubble Space Telescope. Four of Saturn's moons are visible (clockwise from above right): Enceladus (499 kilometers, or 310 miles across); Mimas (396 kilometers, or 245 miles across); Tethys (1,060 kilometers, or 659 miles across); and Rhea (1,528 kilometers, or 949 miles across). The imaging team enhanced the brightness of Mimas and Enceladus by a factor of three. http://photojournal.jpl.nasa.gov/catalog/PIA05381

  2. The landfill methane balance: Model and practical applications

    SciTech Connect

    Bogner, J.; Spokas, K.

    1995-10-01

    A rational mass-balance framework is described for improved quantification of landfill methane processes at a given site. The methane balance model examines the partitioning of methane generated into methane recovered (via extraction systems), methane emitted, methane oxidized, methane migrated, and methane storage. This model encourages use of field-based data to better quantify rates of methane recovery and emissions.

  3. Methane and Other Greenhouse Gases in the Arctic - Measurements, Process Studies and Modelling (MAMM)

    NASA Astrophysics Data System (ADS)

    Pyle, J. A.; Warwick, N. J.; Cain, M.; Hayman, G.; Skiba, U.; Drewer, J.; Dinsmore, K.; George, C.; Nisbet, E. G.; Lowry, D.; Fisher, R. E.; France, J. L.; Lanoiselle, M.; Brownlow, R. B.; Allen, G.; Bower, K.; Gallagher, M. W.; Percival, C.; Illingworth, S. M.; Jones, B.; Muller, J.; O'Shea, S.; Manning, A. C.; Kozlova, E.; Manning, A. J.; Smith, M.; Anderson, D.; Bauguitte, S.

    2013-12-01

    The Arctic is a major source of atmospheric methane and other greenhouse gases, of both natural and anthropogenic origin. Arctic greenhouse gas sources need to be quantified, by strength, geographic location, character (e.g. wetlands, gas fields, hydrates), and by temporal variation (daily, seasonally and annually), and their vulnerability to change assessed. To this end, the MAMM project was commissioned as part of the UK NERC Arctic Research Programme. It involves an integrated series of measurement and modelling activities. Analysis of atmospheric gas concentrations, isotopic character, and source fluxes, are being made from both the ground and from the NERC FAAM (Facility for Airborne Atmospheric Measurements) aircraft. The measurements (historic and new) are being interpreted using a suite of models (trajectory, forward and inverse) to improve the understanding of the local/regional scale, placing the role of Arctic emissions in the context of large-scale global atmospheric change. The first measurement campaign was held in August 2012. Surface flux measurements were made at the Sodankylä research station in Finland, together with in-situ surface and aircraft measurements over a wider area. In addition to flights over the Sodankylä wetlands, the aircraft also flew out to Svalbard, Norway to investigate marine sources of methane. Further campaigns are taking place in Sweden in August and September 2013. The initial measurements have been used to infer wetland emission fluxes and confirm that Scandinavian wetlands are a major source of methane in this region (see posters by Fisher et al, O'Shea et al). The aircraft also measured a high-methane plume over the sea between mainland Norway and Svalbard, which was likely advected from mainland wetland sources (see poster by France et al). Results from the field campaigns will be presented, alongside results from the NAME model (the UK Met Office's Numerical Atmospheric dispersion Modelling Environment) to help

  4. Liquid Methane/Oxygen Injector Study for Mars Ascent Engines

    NASA Technical Reports Server (NTRS)

    Trinh, Huu Phuoc

    1999-01-01

    As a part of the advancing technology of the cryogenic propulsion system for the Mars exploration mission, this effort aims at evaluating propellant injection concepts for liquid methane/liquid oxygen (LOX) rocket engines. Split-triplet and unlike impinging injectors were selected for this study. A total of four injector configurations were tested under combustion conditions in a modular combustor test article (MCTA), equipped with optically accessible windows, at MSFC. A series of forty hot-fire tests, which covered a wide range of engine operating conditions with the chamber pressure ranging from 320 to 510 and the mixture ratio from 1.5 to 3.5, were conducted. The test matrix also included a variation in the combustion chamber length for the purpose of investigating its effects on the combustion performance and stability. Initial assessments of the test results showed that the injectors provided stable combustion and there were no injector face overheating problems under all operating conditions. The Raman scattering signal measurement method was successfully demonstrated for the hydrocarbon/oxygen reactive flow field. The near-injector face flow field was visually observed through the use of an infrared camera. Chamber wall temperature, high frequency chamber pressure, and average throat section heat flux were also recorded throughout the test series. Assessments of the injector performance are underway.

  5. Methane Emissions from Deciduous Trees

    NASA Astrophysics Data System (ADS)

    Rice, A. L.; Teama, D.; Khalil, M. K.; Shearer, M. J.; Rosenstiel, T. N.

    2008-12-01

    There is some disagreement today over whether terrestrial plants present a significant source of methane to the atmosphere. Even if the plants are recognized as a source, there is no clear method to extrapolate plant emissions to the global atmospheric budget of methane and estimates vary widely. There is also no consensus on a mechanism for methane production and/or plant-mediated transport to the atmosphere. Here, we present preliminary data showing a significant flux of methane to the atmosphere from three wetland deciduous tree species. Ash (Fraxinus latifolia), cottonwood (Populus deltoides L.), and willow (Salix fluviatillis) were grown in a greenhouse under inundated rice-cultivation conditions using a rice straw amendment equivalent to 3 t/ha to enhance below ground anaerobic methane production. Results of measurements of redox potential and methane concentrations in soil pore water show significant methane production similar to that observed in rice plots (Oryza sative L. 'M-103') and controls of the same treatment. Measurements of the stable carbon isotopic composition (δ13C) of methane dissolved in soil pore water show no significant difference from rice plots showing no discernable difference in bulk carbon substrate. Methane flux from trees, measured using static flux chamber and bag-tree enclosures, was found to be significantly higher than control treatments (i.e., no plants) but lower than rice plants overall. The carbon isotopic composition of emitted methane from tree species was found to be approximately 8‰ enriched in δ13C compared with methane emitted from rice. This difference in δ13C of emitted methane observed between rice and trees suggests the mechanisms contributing to regulating plant-mediated methane transport (e.g. transport, oxidation, carbon sources) may be quite distinct between diverse plant functional types. Identifying the mechanistic basis of this response will be a key development towards developing more accurate estimates

  6. Release of entrapped methane from wetland rice fields upon soil drying

    SciTech Connect

    Gon, H.A.C.D. van der; Breemen, N. van; Neue, H.U.

    1996-03-01

    Methane emissions from rice paddies were monitored to determine the dynamics of methane release during evaporative drying. Two clay soils and one calcareous sandy loam, all from Philippine rice paddies, were examined. The soils were fertilized with urea or green manure, and/or amended with gypsum. Monitoring data was collected for several weeks after harvesting 1992 dry and wet season crops. Methane emission was monitored automatically with a closed chamber technique using 24-hour semincontinuous determination of methane emission rates from different gas collector chambers. In all plots, very high emissions of methane to the atmosphere during the early phase of soil drying was observed. It was not determined whether this was due to the drainage method or partly attributable to low time resolution sampling. The total amount of methane emitted depended on the fertilizer and/or soil amendment. However, the ratio of the methane released during evaporative drying and methane emitted during the growing seasons was approximately constant. Therefore, methane during soil drying is a significant component of the total methane emitted from a rice paddy. Neglecting this component could cause total methane emission during a rice crop cycle to be underestimated by about 10 percent. 14 refs., 4 figs., 3 tabs.

  7. Dissolved methane in the US GEOTRACES Arctic section

    NASA Astrophysics Data System (ADS)

    Whitmore, L. M.; Shiller, A. M.

    2016-02-01

    Methane is a greenhouse gas with a warming potential greater than that of carbon dioxide. The sediments of the Arctic Ocean are host to large reservoirs of methane which may be released as a consequence of climate change and thereby serve as a positive feedback. Determination of the distribution of dissolved methane in the Arctic Ocean and fluxes of this gas to the atmosphere is thus of great interest. We are currently determining dissolved methane in the Arctic Ocean, both in discrete samples from Niskin bottles as well as in continuous underway surface sampling, as part of the US GEOTRACES Arctic section. This section began in the Aleutians, headed north through the Bering and Chukchi Seas and arrived at the North Pole on 5 Sept. 2015 aboard USCGC Healy before heading south again. Preliminary results show near-surface dissolved methane concentrations ranging from near atmospheric equilibrium to values at least double atmospheric. With depth, concentrations typically increase to maxima associated with either the chlorophyll max or with apparent off-shelf methane transport. In deep waters of the Makarov Basin, dissolved methane is near 1 nM in concentration, similar to deep waters of other ocean basins.

  8. Development of Sand Production Evaluation Apparatus for Methane Hydrate Development

    NASA Astrophysics Data System (ADS)

    Kakumoto, M.; Yoneda, J.; Tenma, N.; Katagiri, J.; Noda, S.

    2015-12-01

    As a part of a Japanese National hydrate research program (MH21, funded by METI), we performed a study on sand production mechanism during methane gas production. In 2013, the first methane hydrate offshore production test was conducted in Japan, and it was recognized in the production of about 20000m3/day of methane gas from methane hydrate bearing sand sediment in deep marine sediment. In methane hydrate development, depressurization method has been proposed for gas extraction. This method is a method to reduce the bottom hole pressure by submersible pump lowering water level in the production well, and gas and water is recovered by methane hydrate dissociation at the in situ. At that time, a phenomenon that sand flows into the wells is feared. In actually, sand production phenomenon occurred after 6 days from production start in offshore production test. A mechanism of sand production has not yet been resolved in case of methane hydrate development. Therefore, we developed large scale laboratory test apparatus for the purpose of elucidation of the mechanism of sand production phenomenon. In this presentation, we introduce basic performance of this apparatus, and usefulness is made mention by representative test results.

  9. Charters, Constitutions and By-Laws of the Indian Tribes of North America. Part II: The Indian Tribes of Wisconsin (Great Lakes Agency). Occasional Publications in Anthropology, Ethnology Series, No. 2.

    ERIC Educational Resources Information Center

    Fay, George E., Comp.

    Part II of a series of publications consisting of American Indian tribal governmental documents, this volume includes charters, constitutions, and by-laws of Indian tribes of Wisconsin (Great Lakes Agency). Documents are included relative to the Bad River, Lac Courte Oreilles, Lac du Flambeau, and the Red Cliff bands of Lake Superior Chippewa…

  10. Charters, Constitutions and By-Laws of the Indian Tribes of North America, Part XII: The Basin-Plateau Tribes (cont'd.). Occasional Publications in Anthropology, Ethnology Series, No. 13.

    ERIC Educational Resources Information Center

    Fay, George E., Comp.

    The Museum of Anthropology, University of Northern Colorado at Greeley, has assembled various American Indian tribal charters, constitutions, and by-laws to comprise a series of publications. The present volume, Part XII, is a continuation of the publication on Basin-Plateau Indian groups: the Ely Indian Colony and Reno-Sparks Indian Colony of…

  11. Practical uses of liquid methane in rocket engine applications

    NASA Astrophysics Data System (ADS)

    Neill, Todd; Judd, Donald; Veith, Eric; Rousar, Donald

    2009-09-01

    Liquid methane has been considered an attractive rocket propellant for several decades. However, most rocket engine development efforts in the last 30 years have focused on using more traditional fuels such as hydrogen, kerosene, and earth storables, without any serious development or application of methane to propulsion systems. This paper presents a summary of recent 870 lbf thrust LOX/LCH4 (liquid oxygen/liquid methane) engine test results and recent LOX/LCH4 torch igniter testing. Multiple test series were conducted using both radiation cooled and ablative chamber hardware. This engine testing yielded measured minimum C* efficiencies of 97% using non-optimized engine hardware, with expectations that better than 99% efficiency can readily be achieved with minor hardware optimization. The combustion process was shown to be stable in all tests and the operating transition from poor quality methane (two-phase fluid) at startup to liquid-liquid, sub-cooled, steady state operation was demonstrated. Engine test results showed chamber wall compatibility with high propellant mixture ratios and excellent boundary layer performance of methane as a chamber film coolant. The Aerojet work on methane propulsion and energy applications is also briefly summarized.

  12. Methane emissions from northern Amazon savanna wetlands and Balbina Reservoir

    NASA Astrophysics Data System (ADS)

    Kemenes, A.; Belger, L.; Forsberg, B.; Melack, J. M.

    2006-12-01

    To improve estimates of methane emission for the Amazon basin requires information from aquatic environments not represented in the central basin near the Solimoes River, where most of the current data were obtained. We have combined intensive, year-long measurements of methane emission and water levels made in interfluvial wetlands located in the upper Negro basin with calculations of inundation based on a time series of Radarsat synthetic aperature radar images. These grass-dominated savannas emitted methane at an average rate of 18 mg C per m squared per day, a low rate compared to the habitats with floating grasses the occur in the Solimoes floodplains. Reservoirs constructed in the Amazon typically flood forested landscapes and lead to conditions conducive for methane production. The methane is released to the atmosphere from the reservoir and as the water exits the turbines and from the downstream river. Balbina Reservoir near Manaus covers about 2400 km squared along the Uatuma River. Annual averages of measurements of methane emission from the various habitats in the reservoir range from 23 to 64 mg C per m squared per day. Total annual emission from the reservoir is about 58 Gg C. In addition, about 39 Gg C per year are released below the dam, about 50 percent of which is released as the water passes through the turbines. On an annual areal basis, Balbina Reservoir emits 40 Mg C km squared, in contrast to 30 Mg km squared for the Solimoes mainstem floodplain

  13. Project identification for methane reduction options

    SciTech Connect

    Kerr, T.

    1996-12-31

    This paper discusses efforts directed at reduction in emission of methane to the atmosphere. Methane is a potent greenhouse gas, which on a 20 year timeframe may present a similar problem to carbon dioxide. In addition, methane causes additional problems in the form of smog and its longer atmospheric lifetime. The author discusses strategies for reducing methane emission from several major sources. This includes landfill methane recovery, coalbed methane recovery, livestock methane reduction - in the form of ruminant methane reduction and manure methane recovery. The author presents examples of projects which have implemented these ideas, the economics of the projects, and additional gains which come from the projects.

  14. Methane cycling. Nonequilibrium clumped isotope signals in microbial methane.

    PubMed

    Wang, David T; Gruen, Danielle S; Lollar, Barbara Sherwood; Hinrichs, Kai-Uwe; Stewart, Lucy C; Holden, James F; Hristov, Alexander N; Pohlman, John W; Morrill, Penny L; Könneke, Martin; Delwiche, Kyle B; Reeves, Eoghan P; Sutcliffe, Chelsea N; Ritter, Daniel J; Seewald, Jeffrey S; McIntosh, Jennifer C; Hemond, Harold F; Kubo, Michael D; Cardace, Dawn; Hoehler, Tori M; Ono, Shuhei

    2015-04-24

    Methane is a key component in the global carbon cycle, with a wide range of anthropogenic and natural sources. Although isotopic compositions of methane have traditionally aided source identification, the abundance of its multiply substituted "clumped" isotopologues (for example, (13)CH3D) has recently emerged as a proxy for determining methane-formation temperatures. However, the effect of biological processes on methane's clumped isotopologue signature is poorly constrained. We show that methanogenesis proceeding at relatively high rates in cattle, surface environments, and laboratory cultures exerts kinetic control on (13)CH3D abundances and results in anomalously elevated formation-temperature estimates. We demonstrate quantitatively that H2 availability accounts for this effect. Clumped methane thermometry can therefore provide constraints on the generation of methane in diverse settings, including continental serpentinization sites and ancient, deep groundwaters.

  15. 32 CFR Appendix C to Part 197 - Procedures for the Department of State (DoS) Foreign Relations of the United States (FRUS) Series

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... the DoS for the FRUS series under Public Law No. 102-138. b. Request authorization from the CIA, NSC.... Submit to the respective Agency a list of CIA and NSC documents copied and released to the...

  16. 32 CFR Appendix C to Part 197 - Procedures for the Department of State (DoS) Foreign Relations of the United States (FRUS) Series

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... the DoS for the FRUS series under Public Law No. 102-138. b. Request authorization from the CIA, NSC.... Submit to the respective Agency a list of CIA and NSC documents copied and released to the...

  17. 32 CFR Appendix C to Part 197 - Procedures for the Department of State (DoS) Foreign Relations of the United States (FRUS) Series

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... the DoS for the FRUS series under Public Law No. 102-138. b. Request authorization from the CIA, NSC.... Submit to the respective Agency a list of CIA and NSC documents copied and released to the...

  18. 32 CFR Appendix C to Part 197 - Procedures for the Department of State (DoS) Foreign Relations of the United States (FRUS) Series

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... the DoS for the FRUS series under Public Law No. 102-138. b. Request authorization from the CIA, NSC.... Submit to the respective Agency a list of CIA and NSC documents copied and released to the...

  19. 32 CFR Appendix C to Part 197 - Procedures for the Department of State (DoS) Foreign Relations of the United States (FRUS) Series

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the DoS for the FRUS series under Public Law No. 102-138. b. Request authorization from the CIA, NSC.... Submit to the respective Agency a list of CIA and NSC documents copied and released to the...

  20. Scrutinizing compost properties and their impact on methane oxidation efficiency.

    PubMed

    Huber-Humer, Marion; Tintner, Johannes; Böhm, Katharina; Lechner, Peter

    2011-05-01

    Methane emissions from active or closed landfills can be reduced by means of microbial methane oxidation enhanced by properly designed landfill covers and engineered biocovers. Composts produced using different waste materials have already been proven to support methane oxidation, and may represent a low-cost alternative to other suitable substrates such as sandy or humic-rich soils, which are frequently not available in sufficient amounts or are too costly. In the present study a data set of 30 different compost materials (different age and input materials) and mixtures, as well as seven soils and mineral substrates were tested to assess methane oxidation rate under similar conditions in a laboratory column set-up. Multivariate data analysis (discriminant analysis) was applied to predict the influence of 21 different parameters (chemical, maturation and physical) on methane oxidation rate in a PLS-DA model. The results show that bulk density, total nutrient content (nitrogen and phosphorus), as well as the quantity and quality (with respect to maturity) of organic matter determined methane oxidation rate in this data set. The model explained 50% of the data variation, indicating how characterisation of oxidation rate by single, even diverse conventional parameters was limited. Thus for the first time, Fourier Transform Infrared (FTIR) spectroscopy was applied to a series of samples to better determine the characteristics of methane-oxidising materials. The initial data obtained in this study appear to be most promising. The prediction of specific methane oxidation rate of a potential biocover material from FTIR spectra and multivariate data analyses is a target to be focused on in the future. Copyright © 2010 Elsevier Ltd. All rights reserved.

  1. Low upper limit to methane abundance on Mars.

    PubMed

    Webster, Christopher R; Mahaffy, Paul R; Atreya, Sushil K; Flesch, Gregory J; Farley, Kenneth A

    2013-10-18

    By analogy with Earth, methane in the Martian atmosphere is a potential signature of ongoing or past biological activity. During the past decade, Earth-based telescopic observations reported "plumes" of methane of tens of parts per billion by volume (ppbv), and those from Mars orbit showed localized patches, prompting speculation of sources from subsurface bacteria or nonbiological sources. From in situ measurements made with the Tunable Laser Spectrometer (TLS) on Curiosity using a distinctive spectral pattern specific to methane, we report no detection of atmospheric methane with a measured value of 0.18 ± 0.67 ppbv corresponding to an upper limit of only 1.3 ppbv (95% confidence level), which reduces the probability of current methanogenic microbial activity on Mars and limits the recent contribution from extraplanetary and geologic sources.

  2. World-wide increase in tropospheric methane, 1978-1983

    NASA Technical Reports Server (NTRS)

    Blake, D. R.; Rowland, F. S.

    1986-01-01

    Techniques used to assess methane concentration in the troposphere are described, and data obtained during the period from 1978 to 1983 are presented in detail. Tropospheric methane concentrations in remote locations averaged a yearly world-wide increase of 0.018 + or - 0.002 parts per million by volume (ppmv). Average world-wide tropospheric concentration of methane in dry air was 1.625 ppmv at the end of 1983 measured against an NBS standard certified as 0.97 ppmv. Contributing to this steady increase in methane concentration are increases in the source strengths from cattle and rice fields, which in turn result from CO, CH4 and HO coupling. Among the physical and chemical effects is an increase in greenhouse warming of about 0.04 C per decade.

  3. Low Upper Limit to Methane Abundance on Mars

    NASA Astrophysics Data System (ADS)

    Webster, Christopher R.; Mahaffy, Paul R.; Atreya, Sushil K.; Flesch, Gregory J.; Farley, Kenneth A.; Kemppinen, Osku; Bridges, Nathan; Johnson, Jeffrey R.; Minitti, Michelle; Cremers, David; Bell, James F.; Edgar, Lauren; Farmer, Jack; Godber, Austin; Wadhwa, Meenakshi; Wellington, Danika; McEwan, Ian; Newman, Claire; Richardson, Mark; Charpentier, Antoine; Peret, Laurent; King, Penelope; Blank, Jennifer; Weigle, Gerald; Schmidt, Mariek; Li, Shuai; Milliken, Ralph; Robertson, Kevin; Sun, Vivian; Baker, Michael; Edwards, Christopher; Ehlmann, Bethany; Farley, Kenneth; Griffes, Jennifer; Grotzinger, John; Miller, Hayden; Newcombe, Megan; Pilorget, Cedric; Rice, Melissa; Siebach, Kirsten; Stack, Katie; Stolper, Edward; Brunet, Claude; Hipkin, Victoria; Léveillé, Richard; Marchand, Geneviève; Sánchez, Pablo Sobrón; Favot, Laurent; Cody, George; Steele, Andrew; Flückiger, Lorenzo; Lees, David; Nefian, Ara; Martin, Mildred; Gailhanou, Marc; Westall, Frances; Israël, Guy; Agard, Christophe; Baroukh, Julien; Donny, Christophe; Gaboriaud, Alain; Guillemot, Philippe; Lafaille, Vivian; Lorigny, Eric; Paillet, Alexis; Pérez, René; Saccoccio, Muriel; Yana, Charles; Armiens-Aparicio, Carlos; Rodríguez, Javier Caride; Blázquez, Isaías Carrasco; Gómez, Felipe Gómez; Elvira, Javier Gómez; Hettrich, Sebastian; Malvitte, Alain Lepinette; Jiménez, Mercedes Marín; Martínez-Frías, Jesús; Soler, Javier Martín; Martín-Torres, F. Javier; Jurado, Antonio Molina; Mora-Sotomayor, Luis; Caro, Guillermo Muñoz; López, Sara Navarro; Peinado-González, Verónica; Pla-García, Jorge; Manfredi, José Antonio Rodriguez; Romeral-Planelló, Julio José; Fuentes, Sara Alejandra Sans; Martinez, Eduardo Sebastian; Redondo, Josefina Torres; Urqui-O'Callaghan, Roser; Mier, María-Paz Zorzano; Chipera, Steve; Lacour, Jean-Luc; Mauchien, Patrick; Sirven, Jean-Baptiste; Manning, Heidi; Fairén, Alberto; Hayes, Alexander; Joseph, Jonathan; Squyres, Steven; Sullivan, Robert; Thomas, Peter; Dupont, Audrey; Lundberg, Angela; Melikechi, Noureddine; Mezzacappa, Alissa; DeMarines, Julia; Grinspoon, David; Reitz, Günther; Prats, Benito; Atlaskin, Evgeny; Genzer, Maria; Harri, Ari-Matti; Haukka, Harri; Kahanpää, Henrik; Kauhanen, Janne; Kemppinen, Osku; Paton, Mark; Polkko, Jouni; Schmidt, Walter; Siili, Tero; Fabre, Cécile; Wray, James; Wilhelm, Mary Beth; Poitrasson, Franck; Patel, Kiran; Gorevan, Stephen; Indyk, Stephen; Paulsen, Gale; Gupta, Sanjeev; Bish, David; Schieber, Juergen; Gondet, Brigitte; Langevin, Yves; Geffroy, Claude; Baratoux, David; Berger, Gilles; Cros, Alain; d'Uston, Claude; Forni, Olivier; Gasnault, Olivier; Lasue, Jérémie; Lee, Qiu-Mei; Maurice, Sylvestre; Meslin, Pierre-Yves; Pallier, Etienne; Parot, Yann; Pinet, Patrick; Schröder, Susanne; Toplis, Mike; Lewin, Éric; Brunner, Will; Heydari, Ezat; Achilles, Cherie; Oehler, Dorothy; Sutter, Brad; Cabane, Michel; Coscia, David; Israël, Guy; Szopa, Cyril; Dromart, Gilles; Robert, François; Sautter, Violaine; Le Mouélic, Stéphane; Mangold, Nicolas; Nachon, Marion; Buch, Arnaud; Stalport, Fabien; Coll, Patrice; François, Pascaline; Raulin, François; Teinturier, Samuel; Cameron, James; Clegg, Sam; Cousin, Agnès; DeLapp, Dorothea; Dingler, Robert; Jackson, Ryan Steele; Johnstone, Stephen; Lanza, Nina; Little, Cynthia; Nelson, Tony; Wiens, Roger C.; Williams, Richard B.; Jones, Andrea; Kirkland, Laurel; Treiman, Allan; Baker, Burt; Cantor, Bruce; Caplinger, Michael; Davis, Scott; Duston, Brian; Edgett, Kenneth; Fay, Donald; Hardgrove, Craig; Harker, David; Herrera, Paul; Jensen, Elsa; Kennedy, Megan R.; Krezoski, Gillian; Krysak, Daniel; Lipkaman, Leslie; Malin, Michael; McCartney, Elaina; McNair, Sean; Nixon, Brian; Posiolova, Liliya; Ravine, Michael; Salamon, Andrew; Saper, Lee; Stoiber, Kevin; Supulver, Kimberley; Van Beek, Jason; Van Beek, Tessa; Zimdar, Robert; French, Katherine Louise; Iagnemma, Karl; Miller, Kristen; Summons, Roger; Goesmann, Fred; Goetz, Walter; Hviid, Stubbe; Johnson, Micah; Lefavor, Matthew; Lyness, Eric; Breves, Elly; Dyar, M. Darby; Fassett, Caleb; Blake, David F.; Bristow, Thomas; DesMarais, David; Edwards, Laurence; Haberle, Robert; Hoehler, Tori; Hollingsworth, Jeff; Kahre, Melinda; Keely, Leslie; McKay, Christopher; Wilhelm, Mary Beth; Bleacher, Lora; Brinckerhoff, William; Choi, David; Conrad, Pamela; Dworkin, Jason P.; Eigenbrode, Jennifer; Floyd, Melissa; Freissinet, Caroline; Garvin, James; Glavin, Daniel; Harpold, Daniel; Jones, Andrea; Mahaffy, Paul; Martin, David K.; McAdam, Amy; Pavlov, Alexander; Raaen, Eric; Smith, Michael D.; Stern, Jennifer; Tan, Florence; Trainer, Melissa; Meyer, Michael; Posner, Arik; Voytek, Mary; Anderson, Robert C.; Aubrey, Andrew; Beegle, Luther W.; Behar, Alberto; Blaney, Diana; Brinza, David; Calef, Fred; Christensen, Lance; Crisp, Joy A.; DeFlores, Lauren; Ehlmann, Bethany; Feldman, Jason; Feldman, Sabrina; Flesch, Gregory; Hurowitz, Joel; Jun, Insoo; Keymeulen, Didier; Maki, Justin; Mischna, Michael; Morookian, John Michael; Parker, Timothy; Pavri, Betina; Schoppers, Marcel; Sengstacken, Aaron; Simmonds, John J.; Spanovich, Nicole; Juarez, Manuel de la Torre; Vasavada, Ashwin R.; Webster, Christopher R.; Yen, Albert; Archer, Paul Douglas; Cucinotta, Francis; Jones, John H.; Ming, Douglas; Morris, Richard V.; Niles, Paul; Rampe, Elizabeth; Nolan, Thomas; Fisk, Martin; Radziemski, Leon; Barraclough, Bruce; Bender, Steve; Berman, Daniel; Dobrea, Eldar Noe; Tokar, Robert; Vaniman, David; Williams, Rebecca M. E.; Yingst, Aileen; Lewis, Kevin; Leshin, Laurie; Cleghorn, Timothy; Huntress, Wesley; Manhès, Gérard; Hudgins, Judy; Olson, Timothy; Stewart, Noel; Sarrazin, Philippe; Grant, John; Vicenzi, Edward; Wilson, Sharon A.; Bullock, Mark; Ehresmann, Bent; Hamilton, Victoria; Hassler, Donald; Peterson, Joseph; Rafkin, Scot; Zeitlin, Cary; Fedosov, Fedor; Golovin, Dmitry; Karpushkina, Natalya; Kozyrev, Alexander; Litvak, Maxim; Malakhov, Alexey; Mitrofanov, Igor; Mokrousov, Maxim; Nikiforov, Sergey; Prokhorov, Vasily; Sanin, Anton; Tretyakov, Vladislav; Varenikov, Alexey; Vostrukhin, Andrey; Kuzmin, Ruslan; Clark, Benton; Wolff, Michael; McLennan, Scott; Botta, Oliver; Drake, Darrell; Bean, Keri; Lemmon, Mark; Schwenzer, Susanne P.; Anderson, Ryan B.; Herkenhoff, Kenneth; Lee, Ella Mae; Sucharski, Robert; Hernández, Miguel Ángel de Pablo; Ávalos, Juan José Blanco; Ramos, Miguel; Kim, Myung-Hee; Malespin, Charles; Plante, Ianik; Muller, Jan-Peter; Navarro-González, Rafael; Ewing, Ryan; Boynton, William; Downs, Robert; Fitzgibbon, Mike; Harshman, Karl; Morrison, Shaunna; Dietrich, William; Kortmann, Onno; Palucis, Marisa; Sumner, Dawn Y.; Williams, Amy; Lugmair, Günter; Wilson, Michael A.; Rubin, David; Jakosky, Bruce; Balic-Zunic, Tonci; Frydenvang, Jens; Jensen, Jaqueline Kløvgaard; Kinch, Kjartan; Koefoed, Asmus; Madsen, Morten Bo; Stipp, Susan Louise Svane; Boyd, Nick; Campbell, John L.; Gellert, Ralf; Perrett, Glynis; Pradler, Irina; VanBommel, Scott; Jacob, Samantha; Owen, Tobias; Rowland, Scott; Atlaskin, Evgeny; Savijärvi, Hannu; Boehm, Eckart; Böttcher, Stephan; Burmeister, Sönke; Guo, Jingnan; Köhler, Jan; García, César Martín; Mueller-Mellin, Reinhold; Wimmer-Schweingruber, Robert; Bridges, John C.; McConnochie, Timothy; Benna, Mehdi; Franz, Heather; Bower, Hannah; Brunner, Anna; Blau, Hannah; Boucher, Thomas; Carmosino, Marco; Atreya, Sushil; Elliott, Harvey; Halleaux, Douglas; Rennó, Nilton; Wong, Michael; Pepin, Robert; Elliott, Beverley; Spray, John; Thompson, Lucy; Gordon, Suzanne; Newsom, Horton; Ollila, Ann; Williams, Joshua; Vasconcelos, Paulo; Bentz, Jennifer; Nealson, Kenneth; Popa, Radu; Kah, Linda C.; Moersch, Jeffrey; Tate, Christopher; Day, Mackenzie; Kocurek, Gary; Hallet, Bernard; Sletten, Ronald; Francis, Raymond; McCullough, Emily; Cloutis, Ed; ten Kate, Inge Loes; Kuzmin, Ruslan; Arvidson, Raymond; Fraeman, Abigail; Scholes, Daniel; Slavney, Susan; Stein, Thomas; Ward, Jennifer; Berger, Jeffrey; Moores, John E.

    2013-10-01

    By analogy with Earth, methane in the Martian atmosphere is a potential signature of ongoing or past biological activity. During the past decade, Earth-based telescopic observations reported “plumes” of methane of tens of parts per billion by volume (ppbv), and those from Mars orbit showed localized patches, prompting speculation of sources from subsurface bacteria or nonbiological sources. From in situ measurements made with the Tunable Laser Spectrometer (TLS) on Curiosity using a distinctive spectral pattern specific to methane, we report no detection of atmospheric methane with a measured value of 0.18 ± 0.67 ppbv corresponding to an upper limit of only 1.3 ppbv (95% confidence level), which reduces the probability of current methanogenic microbial activity on Mars and limits the recent contribution from extraplanetary and geologic sources.

  4. Mars atmosphere. Mars methane detection and variability at Gale crater.

    PubMed

    Webster, Christopher R; Mahaffy, Paul R; Atreya, Sushil K; Flesch, Gregory J; Mischna, Michael A; Meslin, Pierre-Yves; Farley, Kenneth A; Conrad, Pamela G; Christensen, Lance E; Pavlov, Alexander A; Martín-Torres, Javier; Zorzano, María-Paz; McConnochie, Timothy H; Owen, Tobias; Eigenbrode, Jennifer L; Glavin, Daniel P; Steele, Andrew; Malespin, Charles A; Archer, P Douglas; Sutter, Brad; Coll, Patrice; Freissinet, Caroline; McKay, Christopher P; Moores, John E; Schwenzer, Susanne P; Bridges, John C; Navarro-Gonzalez, Rafael; Gellert, Ralf; Lemmon, Mark T

    2015-01-23

    Reports of plumes or patches of methane in the martian atmosphere that vary over monthly time scales have defied explanation to date. From in situ measurements made over a 20-month period by the tunable laser spectrometer of the Sample Analysis at Mars instrument suite on Curiosity at Gale crater, we report detection of background levels of atmospheric methane of mean value 0.69 ± 0.25 parts per billion by volume (ppbv) at the 95% confidence interval (CI). This abundance is lower than model estimates of ultraviolet degradation of accreted interplanetary dust particles or carbonaceous chondrite material. Additionally, in four sequential measurements spanning a 60-sol period (where 1 sol is a martian day), we observed elevated levels of methane of 7.2 ± 2.1 ppbv (95% CI), implying that Mars is episodically producing methane from an additional unknown source.

  5. World-wide increase in tropospheric methane, 1978-1983

    NASA Technical Reports Server (NTRS)

    Blake, D. R.; Rowland, F. S.

    1986-01-01

    Techniques used to assess methane concentration in the troposphere are described, and data obtained during the period from 1978 to 1983 are presented in detail. Tropospheric methane concentrations in remote locations averaged a yearly world-wide increase of 0.018 + or - 0.002 parts per million by volume (ppmv). Average world-wide tropospheric concentration of methane in dry air was 1.625 ppmv at the end of 1983 measured against an NBS standard certified as 0.97 ppmv. Contributing to this steady increase in methane concentration are increases in the source strengths from cattle and rice fields, which in turn result from CO, CH4 and HO coupling. Among the physical and chemical effects is an increase in greenhouse warming of about 0.04 C per decade.

  6. Mars methane detection and variability at Gale crater

    NASA Astrophysics Data System (ADS)

    Webster, Christopher R.; Mahaffy, Paul R.; Atreya, Sushil K.; Flesch, Gregory J.; Mischna, Michael A.; Meslin, Pierre-Yves; Farley, Kenneth A.; Conrad, Pamela G.; Christensen, Lance E.; Pavlov, Alexander A.; Martín-Torres, Javier; Zorzano, María-Paz; McConnochie, Timothy H.; Owen, Tobias; Eigenbrode, Jennifer L.; Glavin, Daniel P.; Steele, Andrew; Malespin, Charles A.; Archer, P. Douglas; Sutter, Brad; Coll, Patrice; Freissinet, Caroline; McKay, Christopher P.; Moores, John E.; Schwenzer, Susanne P.; Bridges, John C.; Navarro-Gonzalez, Rafael; Gellert, Ralf; Lemmon, Mark T.; MSL Science Team; Abbey, William; Achilles, Cherie; Agard, Christophe; Alexandre Alves Verdasca, José; Anderson, Dana; Anderson, Robert C.; Anderson, Ryan B.; Appel, Jan Kristoffer; Archer, Paul Douglas; Arevalo, Ricardo; Armiens-Aparicio, Carlos; Arvidson, Raymond; Atlaskin, Evgeny; Atreya, Andrew Sushil; Azeez, Aubrey Sherif; Baker, Burt; Baker, Michael; Balic-Zunic, Tonci; Baratoux, David; Baroukh, Julien; Barraclough, Bruce; Battalio, Michael; Beach, Michael; Bean, Keri; Beck, Pierre; Becker, Richard; Beegle, Luther; Behar, Alberto; Belgacem, Inès; Bell, James F., III; Bender, Steven; Benna, Mehdi; Bentz, Jennifer; Berger, Jeffrey; Berger, Thomas; Berlanga, Genesis; Berman, Daniel; Bish, David; Blacksberg, Jordana; Blake, David F.; José Blanco, Juan; Blaney, Ávalos Diana; Blank, Jennifer; Blau, Hannah; Bleacher, Lora; Boehm, Eckart; Bonnet, Jean-Yves; Botta, Oliver; Böttcher, Stephan; Boucher, Thomas; Bower, Hannah; Boyd, Nick; Boynton, William; Braswell, Shaneen; Breves, Elly; Bridges, John C.; Bridges, Nathan; Brinckerhoff, William; Brinza, David; Bristow, Thomas; Brunet, Claude; Brunner, Anna; Brunner, Will; Buch, Arnaud; Bullock, Mark; Burmeister, Sönke; Burton, John; Buz, Jennifer; Cabane, Michel; Calef, Fred; Cameron, James; Campbell, John L.; Cantor, Bruce; Caplinger, Michael; Clifton, Carey, Jr.; Caride Rodríguez, Javier; Carmosino, Marco; Carrasco Blázquez, Isaías; Cavanagh, Patrick; Charpentier, Antoine; Chipera, Steve; Choi, David; Christensen, Lance; Clark, Benton; Clegg, Sam; Cleghorn, Timothy; Cloutis, Ed; Cody, George; Coll, Patrice; Coman, Ecaterina I.; Conrad, Pamela; Coscia, David; Cousin, Agnès; Cremers, David; Crisp, Joy A.; Cropper, Kevin; Cros, Alain; Cucinotta, Francis; d'Uston, Claude; Davis, Scott; Day, Mackenzie; Daydou, Yves; DeFlores, Lauren; Dehouck, Erwin; Delapp, Dorothea; DeMarines, Julia; Dequaire, Tristan; Des Marais, David; Desrousseaux, Roch; Dietrich, William; Dingler, Robert; Domagal-Goldman, Shawn; Donny, Christophe; Downs, Robert; Drake, Darrell; Dromart, Gilles; Dupont, Audrey; Duston, Brian; Dworkin, Jason P.; Dyar, M. Darby; Edgar, Lauren; Edgett, Kenneth; Edwards, Christopher S.; Edwards, Laurence; Edwards, Peter; Ehlmann, Bethany; Ehresmann, Bent; Eigenbrode, Jennifer; Elliott, Beverley; Elliott, Harvey; Ewing, Ryan; Fabre, Cécile; Fairén, Alberto; Fairén, Alberto; Farley, Kenneth; Farmer, Jack; Fassett, Caleb; Favot, Laurent; Fay, Donald; Fedosov, Fedor; Feldman, Jason; Fendrich, Kim; Fischer, Erik; Fisk, Martin; Fitzgibbon, Mike; Flesch, Gregory; Floyd, Melissa; Flückiger, Lorenzo; Forni, Olivier; Fox, Valerie; Fraeman, Abigail; Francis, Raymond; François, Pascaline; Franz, Heather; Freissinet, Caroline; French, Katherine Louise; Frydenvang, Jens; Garvin, James; Gasnault, Olivier; Geffroy, Claude; Gellert, Ralf; Genzer, Maria; Getty, Stephanie; Glavin, Daniel; Godber, Austin; Goesmann, Fred; Goetz, Walter; Golovin, Dmitry; Gómez Gómez, Felipe; Gómez-Elvira, Javier; Gondet, Brigitte; Gordon, Suzanne; Gorevan, Stephen; Graham, Heather; Grant, John; Grinspoon, David; Grotzinger, John; Guillemot, Philippe; Guo, Jingnan; Gupta, Sanjeev; Guzewich, Scott; Haberle, Robert; Halleaux, Douglas; Hallet, Bernard; Hamilton, Victoria; Hand, Kevin; Hardgrove, Craig; Hardy, Keian; Harker, David; Harpold, Daniel; Harri, Ari-Matti; Harshman, Karl; Hassler, Donald; Haukka, Harri; Hayes, Alexander; Herkenhoff, Kenneth; Herrera, Paul; Hettrich, Sebastian; Heydari, Ezat; Hipkin, Victoria; Hoehler, Tori; Hollingsworth, Jeff; Hudgins, Judy; Huntress, Wesley; Hurowitz, Joel; Hviid, Stubbe; Iagnemma, Karl; Indyk, Stephen; Israël, Guy; Jackson, Ryan Steele; Jacob, Samantha; Jakosky, Bruce; Jean-Rigaud, Laurent; Jensen, Elsa; Kløvgaard Jensen, Jaqueline; Johnson, Jeffrey R.; Johnson, Micah; Johnstone, Stephen; Jones, Andrea; Jones, John H.; Joseph, Jonathan; Joulin, Mélissa; Jun, Insoo; Kah, Linda C.; Kahanpää, Henrik; Kahre, Melinda; Kaplan, Hannah; Karpushkina, Natalya; Kashyap, Srishti; Kauhanen, Janne; Keely, Leslie; Kelley, Simon; Kempe, Fabian; Kemppinen, Osku; Kennedy, Megan R.; Keymeulen, Didier; Kharytonov, Alexander; Kim, Myung-Hee; Kinch, Kjartan; King, Penelope; Kirk, Randolph; Kirkland, Laurel; Kloos, Jacob; Kocurek, Gary; Koefoed, Asmus; Köhler, Jan; Kortmann, Onno; Kotrc, Benjamin; Kozyrev, Alexander; Krau, Johannes; Krezoski, ß. Gillian; Kronyak, Rachel; Krysak, Daniel; Kuzmin, Ruslan; Lacour, Jean-Luc; Lafaille, Vivian; Langevin, Yves; Lanza, Nina; Lapôtre, Mathieu; Larif, Marie-France; Lasue, Jérémie; Le Deit, Laetitia; Le Mouélic, Stéphane; Lee, Ella Mae; Lee, Qiu-Mei; Lee, Rebekka; Lees, David; Lefavor, Matthew; Lemmon, Mark; Lepinette, Alain; Lepore, Malvitte Kate; Leshin, Laurie; Léveillé, Richard; Lewin, Éric; Lewis, Kevin; Li, Shuai; Lichtenberg, Kimberly; Lipkaman, Leslie; Lisov, Denis; Little, Cynthia; Litvak, Maxim; Liu, Lu; Lohf, Henning; Lorigny, Eric; Lugmair, Günter; Lundberg, Angela; Lyness, Eric; Madsen, Morten Bo; Magee, Angela; Mahaffy, Paul; Maki, Justin; Mäkinen, Teemu; Malakhov, Alexey; Malespin, Charles; Malin, Michael; Mangold, Nicolas; Manhes, Gerard; Manning, Heidi; Marchand, Geneviève; Marín Jiménez, Mercedes; Martín García, César; Martin, David K.; Martin, Mildred; Martin, Peter; Martínez Martínez, Germán; Martínez-Frías, Jesús; Martín-Sauceda, Jaime; Martín-Soler, Martín Javier; Martín-Torres, F. Javier; Mason, Emily; Matthews, Tristan; Matthiä, Daniel; Mauchien, Patrick; Maurice, Sylvestre; McAdam, Amy; McBride, Marie; McCartney, Elaina; McConnochie, Timothy; McCullough, Emily; McEwan, Ian; McKay, Christopher; McLain, Hannah; McLennan, Scott; McNair, Sean; Melikechi, Noureddine; Mendaza de Cal, Teresa; Merikallio, Sini; Merritt, Sean; Meslin, Pierre-Yves; Meyer, Michael; Mezzacappa, Alissa; Milkovich, Sarah; Millan, Maëva; Miller, Hayden; Miller, Kristen; Milliken, Ralph; Ming, Douglas; Minitti, Michelle; Mischna, Michael; Mitchell, Julie; Mitrofanov, Igor; Moersch, Jeffrey; Mokrousov, Maxim; Molina, Antonio; Moore, Jurado Casey; Moores, John E.; Mora-Sotomayor, Luis; Moreno, Gines; Morookian, John Michael; Morris, Richard V.; Morrison, Shaunna; Mousset, Valérie; Mrigakshi, Alankrita; Mueller-Mellin, Reinhold; Muller, Jan-Peter; Muñoz Caro, Guillermo; Nachon, Marion; Nastan, Abbey; Navarro López, Sara; Navarro González, Rafael; Nealson, Kenneth; Nefian, Ara; Nelson, Tony; Newcombe, Megan; Newman, Claire; Newsom, Horton; Nikiforov, Sergey; Nikitczuk, Matthew; Niles, Paul; Nixon, Brian; Noblet, Audrey; Noe, Eldar; Nolan, Dobrea Thomas; Oehler, Dorothy; Ollila, Ann; Olson, Timothy; Orthen, Tobias; Owen, Tobias; Ozanne, Marie; de Pablo Hernández, Miguel Ángel; Pagel, Hannah; Paillet, Alexis; Pallier, Etienne; Palucis, Marisa; Parker, Timothy; Parot, Yann; Parra, Alex; Patel, Kiran; Paton, Mark; Paulsen, Gale; Pavlov, Alexander; Pavri, Betina; Peinado-González, Verónica; Pepin, Robert; Peret, Laurent; Pérez, René; Perrett, Glynis; Peterson, Joseph; Pilorget, Cedric; Pinet, Patrick; Pinnick, Veronica; Pla-García, Jorge; Plante, Ianik; Poitrasson, Franck; Polkko, Jouni; Popa, Radu; Posiolova, Liliya; Posner, Arik; Pradler, Irina; Prats, Benito; Prokhorov, Vasily; Raaen, Eric; Radziemski, Leon; Rafkin, Scot; Ramos, Miguel; Rampe, Elizabeth; Rapin, William; Raulin, François; Ravine, Michael; Reitz, Günther; Ren, Jun; Rennó, Nilton; Rice, Melissa; Richardson, Mark; Ritter, Birgit; Rivera-Hernández, Frances; Robert, François; Robertson, Kevin; Rodriguez Manfredi, José Antonio; José Romeral-Planelló, Julio; Rowland, Scott; Rubin, David; Saccoccio, Muriel; Said, David; Salamon, Andrew; Sanin, Anton; Sans Fuentes, Sara Alejandra; Saper, Lee; Sarrazin, Philippe; Sautter, Violaine; Savijärvi, Hannu; Schieber, Juergen; Schmidt, Mariek; Schmidt, Walter; Scholes, Daniel; Schoppers, Marcel; Schröder, Susanne; Schwenzer, Susanne P.; Sciascia Borlina, Cauê; Scodary, Anthony; Sebastián Martínez, Eduardo; Sengstacken, Aaron; Shechet, Jennifer Griffes; Shterts, Ruslan; Siebach, Kirsten; Siili, Tero; Simmonds, John J.; Sirven, Jean-Baptiste; Slavney, Susan; Sletten, Ronald; Smith, Michael D.; Sobron Sanchez, Pablo; Spanovich, Nicole; Spray, John; Spring, Justin; Squyres, Steven; Stack, Katie; Stalport, Fabien; Starr, Richard; Stein, Andrew Steele Thomas; Stern, Jennifer; Stewart, Noel; Stewart, Wayne; Stipp, Svane Susan Louise; Stoiber, Kevin; Stolper, Edward; Sucharski, Robert; Sullivan, Robert; Summons, Roger; Sumner, Dawn Y.; Sun, Vivian; Supulver, Kimberley; Sutter, Brad; Szopa, Cyril; Tan, Florence; Tate, Christopher; Teinturier, Samuel; ten Kate, Inge Loes; Thomas, Alicia; Thomas, Peter; Thompson, Lucy; Thuillier, Franck; Thulliez, Emmanual; Tokar, Robert; Toplis, Michael; de la Torre Juárez, Manuel; Torres Redondo, Josefina; Trainer, Melissa; Treiman, Allan; Tretyakov, Vladislav; Ullán-Nieto, Aurora; Urqui-O'Callaghan, Roser; Valentín-Serrano, Patricia; Van Beek, Jason; Van Beek, Tessa; VanBommel, Scott; Vaniman, David; Varenikov, Alexey; Vasavada, Ashwin R.; Vasconcelos, Paulo; de Vicente-Retortillo Rubalcaba, Álvaro; Vicenzi, Edward; Vostrukhin, Andrey; Voytek, Mary; Wadhwa, Meenakshi; Ward, Jennifer; Watkins, Jessica; Webster, Christopher R.; Weigle, Gerald; Wellington, Danika; Westall, Frances; Wiens, Roger; Wilhelm, Mary Beth; Williams, Amy; Williams, Joshua; Williams, Rebecca; Williams, Richard B.; Williford, Kenneth; Wilson, Michael A.; Wilson, Sharon A.; Wimmer-Schweingruber, Robert; Wolff, Michael; Wong, Michael; Wray, James; Yana, Charles; Yen, Albert; Yingst, Aileen; Zeitlin, Cary; Zimdar, Robert; Zorzano Mier, María-Paz

    2015-01-01

    Reports of plumes or patches of methane in the martian atmosphere that vary over monthly time scales have defied explanation to date. From in situ measurements made over a 20-month period by the tunable laser spectrometer of the Sample Analysis at Mars instrument suite on Curiosity at Gale crater, we report detection of background levels of atmospheric methane of mean value 0.69 ± 0.25 parts per billion by volume (ppbv) at the 95% confidence interval (CI). This abundance is lower than model estimates of ultraviolet degradation of accreted interplanetary dust particles or carbonaceous chondrite material. Additionally, in four sequential measurements spanning a 60-sol period (where 1 sol is a martian day), we observed elevated levels of methane of 7.2 ± 2.1 ppbv (95% CI), implying that Mars is episodically producing methane from an additional unknown source.

  7. Methane generation in tropical landfills: simplified methods and field results.

    PubMed

    Machado, Sandro L; Carvalho, Miriam F; Gourc, Jean-Pierre; Vilar, Orencio M; do Nascimento, Julio C F

    2009-01-01

    This paper deals with the use of simplified methods to predict methane generation in tropical landfills. Methane recovery data obtained on site as part of a research program being carried out at the Metropolitan Landfill, Salvador, Brazil, is analyzed and used to obtain field methane generation over time. Laboratory data from MSW samples of different ages are presented and discussed; and simplified procedures to estimate the methane generation potential, Lo, and the constant related to the biodegradation rate, k are applied. The first order decay method is used to fit field and laboratory results. It is demonstrated that despite the assumptions and the simplicity of the adopted laboratory procedures, the values Lo and k obtained are very close to those measured in the field, thus making this kind of analysis very attractive for first approach purposes.

  8. Series Bosch System Development

    NASA Technical Reports Server (NTRS)

    Abney, Morgan B.; Evans, Christopher; Mansell, Matt; Swickrath, Michael

    2012-01-01

    State-of-the-art (SOA) carbon dioxide (CO2) reduction technology for the International Space Station produces methane as a byproduct. This methane is subsequently vented overboard. The associated loss of hydrogen ultimately reduces the mass of oxygen that can be recovered from CO2 in a closed-loop life support system. As an alternative to SOA CO2 reduction technology, NASA is exploring a Series-Bosch system capable of reducing CO2 with hydrogen to form water and solid carbon. This results in 100% theoretical recovery of oxygen from metabolic CO2. In the past, Bosch-based technology did not trade favorably against SOA technology due to a high power demand, low reaction efficiencies, concerns with carbon containment, and large resupply requirements necessary to replace expended catalyst cartridges. An alternative approach to Bosch technology, labeled "Series-Bosch," employs a new system design with optimized multi-stage reactors and a membrane-based separation and recycle capability. Multi-physics modeling of the first stage reactor, along with chemical process modeling of the integrated system, has resulted in a design with potential to trade significantly better than previous Bosch technology. The modeling process and resulting system architecture selection are discussed.

  9. Diffusion of methane (1); water (2); calcium chloride (3)

    NASA Astrophysics Data System (ADS)

    Winkelmann, J.

    This document is part of Subvolume A `Gases in Gases, Liquids and their Mixtures' of Volume 15 `Diffusion in Gases, Liquids and Electrolytes' of Landolt-Börnstein Group IV `Physical Chemistry'. It is part of the chapter of the chapter `Diffusion in Pure Gases' and contains data on diffusion of (1) methane; (2) water; (3) calcium chloride

  10. Determination of Methane Sourcex Globally by Sciamachy

    NASA Astrophysics Data System (ADS)

    Park, J. G.; Park, S. Y.

    2016-06-01

    Since the beginning of the industrial revolution, the atmospheric concentration of carbon dioxide (CO2) has increased by nearly 30%, and the Methane (CH4) concentration has more than doubled. CH4 is the second most important greenhouse gas, after CO2. Emissions, extrapolated from measurements of actual gas flux from wetlands, vary from place to place, even within the same wetland. This high variability makes large-scale estimates difficult and means that average emissions levels include a large degree of estimated uncertainty. The SCIAMACHY instrument on the European Space Agency satellite ENVISAT measured greenhouse gases in the troposphere and stratosphere. In this study, the CH4 source area is extracted by estimating the concentrations of methane emissions from time-series satellite data. Contamination of the data by cloud is interpolated both spatially and temporally. It is assumed that methane emission is negligible over ocean and that the concentration in the ocean area is due to advection from land. Background CH4 concentration on land was defined as the ocean CH4 concentration at the same latitude. Land CH4 emission concentrations show that areas of concentrated high CH4 emission are not in paddy fields only but also in broadleaf evergreen areas in South America and Central Africa.

  11. Minimal geological methane emissions during the Younger Dryas-Preboreal abrupt warming event.

    PubMed

    Petrenko, Vasilii V; Smith, Andrew M; Schaefer, Hinrich; Riedel, Katja; Brook, Edward; Baggenstos, Daniel; Harth, Christina; Hua, Quan; Buizert, Christo; Schilt, Adrian; Fain, Xavier; Mitchell, Logan; Bauska, Thomas; Orsi, Anais; Weiss, Ray F; Severinghaus, Jeffrey P

    2017-08-23

    Methane (CH4) is a powerful greenhouse gas and plays a key part in global atmospheric chemistry. Natural geological emissions (fossil methane vented naturally from marine and terrestrial seeps and mud volcanoes) are thought to contribute around 52 teragrams of methane per year to the global methane source, about 10 per cent of the total, but both bottom-up methods (measuring emissions) and top-down approaches (measuring atmospheric mole fractions and isotopes) for constraining these geological emissions have been associated with large uncertainties. Here we use ice core measurements to quantify the absolute amount of radiocarbon-containing methane ((14)CH4) in the past atmosphere and show that geological methane emissions were no higher than 15.4 teragrams per year (95 per cent confidence), averaged over the abrupt warming event that occurred between the Younger Dryas and Preboreal intervals, approximately 11,600 years ago. Assuming that past geological methane emissions were no lower than today, our results indicate that current estimates of today's natural geological methane emissions (about 52 teragrams per year) are too high and, by extension, that current estimates of anthropogenic fossil methane emissions are too low. Our results also improve on and confirm earlier findings that the rapid increase of about 50 per cent in mole fraction of atmospheric methane at the Younger Dryas-Preboreal event was driven by contemporaneous methane from sources such as wetlands; our findings constrain the contribution from old carbon reservoirs (marine methane hydrates, permafrost and methane trapped under ice) to 19 per cent or less (95 per cent confidence). To the extent that the characteristics of the most recent deglaciation and the Younger Dryas-Preboreal warming are comparable to those of the current anthropogenic warming, our measurements suggest that large future atmospheric releases of methane from old carbon sources are unlikely to occur.

  12. Minimal geological methane emissions during the Younger Dryas-Preboreal abrupt warming event

    NASA Astrophysics Data System (ADS)

    Petrenko, Vasilii V.; Smith, Andrew M.; Schaefer, Hinrich; Riedel, Katja; Brook, Edward; Baggenstos, Daniel; Harth, Christina; Hua, Quan; Buizert, Christo; Schilt, Adrian; Fain, Xavier; Mitchell, Logan; Bauska, Thomas; Orsi, Anais; Weiss, Ray F.; Severinghaus, Jeffrey P.

    2017-08-01

    Methane (CH4) is a powerful greenhouse gas and plays a key part in global atmospheric chemistry. Natural geological emissions (fossil methane vented naturally from marine and terrestrial seeps and mud volcanoes) are thought to contribute around 52 teragrams of methane per year to the global methane source, about 10 per cent of the total, but both bottom-up methods (measuring emissions) and top-down approaches (measuring atmospheric mole fractions and isotopes) for constraining these geological emissions have been associated with large uncertainties. Here we use ice core measurements to quantify the absolute amount of radiocarbon-containing methane (14CH4) in the past atmosphere and show that geological methane emissions were no higher than 15.4 teragrams per year (95 per cent confidence), averaged over the abrupt warming event that occurred between the Younger Dryas and Preboreal intervals, approximately 11,600 years ago. Assuming that past geological methane emissions were no lower than today, our results indicate that current estimates of today’s natural geological methane emissions (about 52 teragrams per year) are too high and, by extension, that current estimates of anthropogenic fossil methane emissions are too low. Our results also improve on and confirm earlier findings that the rapid increase of about 50 per cent in mole fraction of atmospheric methane at the Younger Dryas-Preboreal event was driven by contemporaneous methane from sources such as wetlands; our findings constrain the contribution from old carbon reservoirs (marine methane hydrates, permafrost and methane trapped under ice) to 19 per cent or less (95 per cent confidence). To the extent that the characteristics of the most recent deglaciation and the Younger Dryas-Preboreal warming are comparable to those of the current anthropogenic warming, our measurements suggest that large future atmospheric releases of methane from old carbon sources are unlikely to occur.

  13. Field and experimental evidence for low-O2 affinity of aerobic methane oxidizers in coastal waters

    NASA Astrophysics Data System (ADS)

    Steinle, Lea; Maltby, Johanna; Bange, Hermann; Kock, Annette; Lehmann, Moritz F.; Treude, Tina; Niemann, Helge

    2015-04-01

    The coastal ocean accounts for more than 75 % of the global oceanic methane emissions. An important process in mitigating methane emissions from the seawater to the atmosphere is aerobic methane oxidation (MOx). Coastal oceans are highly dynamic systems, in particular with regard to the variability of temperature, salinity, and oxygen concentrations, all of which are potential key environmental factors controlling MOx. We conducted a two-year time-series study of MOx measurements in the water column of a coastal inlet in the southwestern Baltic Sea (Eckernförde Bay, Boknis Eck Time Series Station, 54°31.823 N, 10°02.764 E, 28 m water depth; www.bokniseck.de). Physicochemical parameters at this station have been monitored since 1957. Seasonal stratification during summer/autumn leads to intermittent oxygen depletion (hypoxic to anoxic) in bottom waters in the later part of the stratification period. The duration of these low-oxygen events increased since the 1970s (Lennartz et al., 2014). Furthermore, the organic-rich seafloor continuously produces methane, which leads to gas ebullition followed by accumulation of dissolved methane in bottom waters (up to 470 nM) and supersaturation (with respect to the atmospheric equilibrium) in surface waters (up to 27 nM). MOx communities were most active in bottom waters (1-5 nM/day), which usually contain the lowest oxygen concentrations (sometimes below the in situ detection limit of ~1 µM). In order to better understand the effect of low oxygen concentrations, and thus of hypoxic and suboxic events, on MOx in coastal systems, we conducted lab-based experiments, during which we adjusted oxygen concentrations to values between 0.2 - 220 µM in methane-rich (~100 nM) Eckernförde Bay waters. These samples were then incubated with trace amounts of tritium-labeled methane to assess first order rate constants of methane oxidation. Highest MOx rates were detected at oxygen concentrations of ~0.5 µM (considerably higher than at

  14. The NIST Atmospheric Methane Gas Standard Scale

    NASA Astrophysics Data System (ADS)

    Rhoderick, G.; Carney, J.; Dlugokencky, E. J.; Kitzis, D.

    2010-12-01

    The National Institute of Standards and Technology (NIST) has entered into a collaboration with the National Oceanic and Atmospheric Administration (NOAA) in Boulder, Colorado on dveloping SI-traceable standards for greenhouse gas monitoring. The Earth System Research Laboratory (ESRL) of NOAA has been designated by the World Meteorological Organization to provide SI-traceable gases to laboratories participating in the WMO climate science community Global Atmosphere Watch program. NOAA has agreed to demonstrate comparability to other National Metrology Institutes under international an existing international agreement (BIPM MRA). NIST and NOAA have begun a series of bilateral comparisons to demonstrate comparability. The Gas Metrology Group at NIST has developed a new suite of atmospheric methane Primary Standard Gas Mixtures (PSMs) that range in amount-of-substance fraction (dry-air mole fraction) from 1700 to 2050 nmol/mol (ppb) with ± 0.03% (0.6 nmol/mol) relative uncertainties (68 % confidence interval). Six levels of standards were made to support NIST programs plus the atmospheric level of 1700-2050 nmol/mol with 30 cylinders total. Each intermediate level was compared to existing NIST PSMs at completion for consistency. The 6th level was also compared to an existing suite of PSMs prepared in 1998. A ratio of the methane in each PSM to a control mixture was calculated by dividing the methane peak area response measured by gas chromatography of a PSM by that of the control. The ratio data and gravimetric mole fractions were plotted to a general least squares program called GenLine (1). The results of this regression are shown in Table 1. The average residual difference between the predicted values and the gravimetric values of the old and new PSMs was 0.08 nmol/mol. NOAA/ESRL has analyzed one of the new PSMs from the NIST atmospheric level suite and has shown good agreement. NOAA has filled 30 cylinders with real air from their Niwot Ridge, Colorado, site and

  15. Methane/nitrogen separation process

    DOEpatents

    Baker, R.W.; Lokhandwala, K.A.; Pinnau, I.; Segelke, S.

    1997-09-23

    A membrane separation process is described for treating a gas stream containing methane and nitrogen, for example, natural gas. The separation process works by preferentially permeating methane and rejecting nitrogen. The authors have found that the process is able to meet natural gas pipeline specifications for nitrogen, with acceptably small methane loss, so long as the membrane can exhibit a methane/nitrogen selectivity of about 4, 5 or more. This selectivity can be achieved with some rubbery and super-glassy membranes at low temperatures. The process can also be used for separating ethylene from nitrogen. 11 figs.

  16. Methane/nitrogen separation process

    DOEpatents

    Baker, Richard W.; Lokhandwala, Kaaeid A.; Pinnau, Ingo; Segelke, Scott

    1997-01-01

    A membrane separation process for treating a gas stream containing methane and nitrogen, for example, natural gas. The separation process works by preferentially permeating methane and rejecting nitrogen. We have found that the process is able to meet natural gas pipeline specifications for nitrogen, with acceptably small methane loss, so long as the membrane can exhibit a methane/nitrogen selectivity of about 4, 5 or more. This selectivity can be achieved with some rubbery and super-glassy membranes at low temperatures. The process can also be used for separating ethylene from nitrogen.

  17. Methanogens, Methane and Gastrointestinal Motility

    PubMed Central

    Triantafyllou, Konstantinos; Chang, Christopher

    2014-01-01

    Anaerobic fermentation of the undigested polysaccharide fraction of carbohydrates produces hydrogen in the intestine which is the substrate for methane production by intestinal methanogens. Hydrogen and methane are excreted in the flatus and in breath giving the opportunity to indirectly measure their production using breath testing. Although methane is detected in 30%-50% of the healthy adult population worldwide, its production has been epidemiologically and clinically associated with constipation related diseases, like constipation predominant irritable bowel syndrome and chronic constipation. While a causative relation is not proven yet, there is strong evidence from animal studies that methane delays intestinal transit, possibly acting as a neuromuscular transmitter. This evidence is further supported by the universal finding that methane production (measured by breath test) is associated with delayed transit time in clinical studies. There is also preliminary evidence that antibiotic reduction of methanogens (as evidenced by reduced methane production) predicts the clinical response in terms of symptomatic improvement in patients with constipation predominant irritable bowel syndrome. However, we have not identified yet the mechanism of action of methane on intestinal motility, and since methane production does not account for all constipation associated cases, there is need for high quality clinical trials to examine methane as a biomarker for the diagnosis or as a biomarker that predicts antibiotic treatment response in patients with constipation related disorders. PMID:24466443

  18. On methane pyrolysis special applications

    NASA Astrophysics Data System (ADS)

    Toncu, D. C.; Toncu, G.; Soleimani, S.

    2015-11-01

    Methane pyrolysis represents one of the most important processes in industrial use, with applications rising from the chemical and petrochemical industry, combustion, materials and protective coatings. Despite the intense research, experimental data lack kinetic aspects, and the thermodynamics involved often leads to inaccurate results when applied to various systems. Carrying out a comparative analysis of several available data on methane pyrolysis, the paper aims to study the phenomenon of methane pyrolysis under different environments (combustion and plasma), concluding on the most possible reaction pathways involved in many of its applications. Computer simulation using different database underlines the conclusion, helping to the understanding of methane pyrolysis importance in future technologies.

  19. Biological and biochemical methane reactions

    NASA Astrophysics Data System (ADS)

    Dalton, H.; Pienkos, P. T.; Stirling, D. I.

    1989-04-01

    The purpose of the project was to characterize the nature of the active site involved in methane activation by enzymes from well characterized and newly isolated methane-oxidizing bacteria. Kinetic and structural studies provided an initial picture of how the soluble methane monooxygenase (MMO) enzyme is structured and operates to selectively oxidize methane to methanol under ambient conditions. Cloning and sequencing of gene coding for some of the sMMO proteins were completed, and 72 strains of methanotrophs were isolated from extreme environments.

  20. Redefining the isotopic boundaries of biogenic methane: Methane from endoevaporites

    NASA Astrophysics Data System (ADS)

    Tazaz, Amanda M.; Bebout, Brad M.; Kelley, Cheryl A.; Poole, Jennifer; Chanton, Jeffrey P.

    2013-06-01

    The recent reports of methane in the atmosphere of Mars, as well as the findings of hypersaline paleoenvironments on that planet, have underscored the need to evaluate the importance of biological (as opposed to geological) trace gas production and consumption, particularly in hypersaline environments. Methane in the atmosphere of Mars may be an indication of extant life, but it may also be a consequence of geologic activity and/or the thermal alteration of ancient organic matter. On Earth these methane sources can be distinguished using stable isotopic analyses and the ratio of methane (C1) to C2 and C3 alkanes present in the gas source (C1/(C2 + C3)). We report here that methane produced in hypersaline environments on Earth has an isotopic composition and alkane content outside the values presently considered to indicate a biogenic origin. Methane-rich bubbles released from sub-aqueous substrates contained δ13CCH4 and δ2HCH4 values ranging from -65‰ to -35‰ and -350‰ to -140‰ respectively. Higher salinity endoevaporites yielded what would be considered non-biogenic methane based upon stable isotopic and alkane content, however incubation of crustal and algal mat samples resulted in methane production with similar isotopic values. Radiocarbon analysis indicated that the production of the methane was from recently fixed carbon. An extension of the isotopic boundaries of biogenic methane is necessary in order to avoid the possibility of false negatives returned from measurements of methane on Mars and other planetary bodies.

  1. Long-term monitoring of methane release and associated oceanographc setting offshore Svalbard

    NASA Astrophysics Data System (ADS)

    Dølven, Knut Ola; Ferre, Benedicte; Frank, Carsten; Mienert, Jürgen

    2017-04-01

    Large amounts of methane are stored in the Arctic Ocean sediments, both as free gas and in form of methane hydrates. Warming of Arctic Ocean bottom water can destabilize methane hydrates and cause extensive methane release to the ocean, influencing marine environments (Åström et al., 2016). Previous oceanographic studies have shown a significant methane release from seep-sites offshore western Svalbard, mainly based on hydrographic snapshots and/or echosounder data. These studies have shown that the methane release has significant temporal variations, and these variations can only be investigated properly with ocean observatories. Two K-Lander ocean observatories, developed in collaboration between CAGE and Kontgberg Maritime were deployed at two of these seep sites at 90 and 240 meter depth, from July 2015 to May 2016. Time series obtained from these two observatories include ocean current profiles, temperature, salinity, pressure, as well as dissolved methane and CO2 concentration. The oceanographic data show a clear seasonal variation and indicates that the water column can be significantly affected by atmospheric forcing during winter season. At the same time, methane concentration shows significant temporal variations on both relatively short (hours) and long (seasonal) time scales, with values ranging from 90 to 800 nmol/kg. The short term variations indicates a non-mixed benthic boundary layer with respect to dissolved methane, while the long term variations may indicate seasonal changes in the vertical transport of methane in the water column. Acknowledgements This project is funded by CAGE (Centre for Arctic Gas Hydrate, Environment and Climate), Norwegian Research Council grant no. 223259. Reference Åström, E. Carrol, M. L., Ambrose, W., Carrol, J. "Arctic cold seeps in marine methane hydrate environments: impacts on shelf macrobenthic community structure offshore Svalbard". Marine Ecology Progress Series, 2016 (1616-1599) 552 p. 1-18.

  2. Lead optimization of the VU0486321 series of mGlu(1) PAMs. Part 2: SAR of alternative 3-methyl heterocycles and progress towards an in vivo tool.

    PubMed

    Garcia-Barrantes, Pedro M; Cho, Hyekyung P; Metts, Adam M; Blobaum, Anna L; Niswender, Colleen M; Conn, P Jeffrey; Lindsley, Craig W

    2016-02-01

    This Letter describes the further lead optimization of the VU0486321 series of mGlu1 positive allosteric modulators (PAMs), driven by recent genetic data linking loss of function GRM1 to schizophrenia. Steep and caveat-laden SAR plagues the series, but ultimately potent mGlu1 PAMs (EC50s ∼5 nM) have resulted with good DMPK properties (low intrinsic clearance, clean CYP profile, modest Fu) and CNS penetration (Kps 0.25-0.97), along with up to >450-fold selectivity versus mGlu4 and mGlu5.

  3. Methane in groundwater used for Japanese agriculture: Its relationship to other physico-chemical properties and possible tropospheric source stength

    SciTech Connect

    Watanabe, A.; Kimura, M. ); Kasuya, M.; Kotake, M.; Katoh, T. )

    1994-01-01

    This paper presents results of measurements of dissolved methane found in ground water samples from Aichi Prefecture, Japan, taken from wells which were used for agricultural irrigation. It is a part of the overall program to account of methane sources and sinks in the environment. Detectable methane concentrations were found in more than half of the 131 samples taken. Based on the detected methane concentrations, and the estimated ground water usage, this source represents only 1.4% of the methane production from paddy fields in this geographic region.

  4. Consumption of atmospheric methane by tundra soils

    NASA Technical Reports Server (NTRS)

    Whalen, S. C.; Reeburgh, W. S.

    1990-01-01

    The results of field and laboratory experiments on methane consumption by tundra soils are reported. For methane concentrations ranging from below to well above ambient, moist soils are found to consume methane rapidly; in nonwaterlogged soils, equilibration with atmospheric methane is fast relative to microbial oxidation. It is concluded that lowering of the water table in tundra as a resulting from a warmer, drier climate will decrease methane fluxes and could cause these areas to provide negative feedback for atmospheric methane.

  5. Consumption of atmospheric methane by tundra soils

    NASA Technical Reports Server (NTRS)

    Whalen, S. C.; Reeburgh, W. S.

    1990-01-01

    The results of field and laboratory experiments on methane consumption by tundra soils are reported. For methane concentrations ranging from below to well above ambient, moist soils are found to consume methane rapidly; in nonwaterlogged soils, equilibration with atmospheric methane is fast relative to microbial oxidation. It is concluded that lowering of the water table in tundra as a resulting from a warmer, drier climate will decrease methane fluxes and could cause these areas to provide negative feedback for atmospheric methane.

  6. Methane production, emission and possible control measures in the rice agriculture

    NASA Astrophysics Data System (ADS)

    Wang, Mingxing; Shangguan, Xingjian; Shen, Renxing; Reiner, Wassmann; Wolfgang, Seiler

    1993-09-01

    In the rice field methane is produced in the soil layer with depths of 2 25 cm. The vertical profile of methane production rate in the paddy soil during the water covering period differs from that in the paddy soil in dry phase. Only a small part, about 30%, of the produced methane is emitted to the atmosphere through rice plant, air bubbles, and molecular diffusion. Therefore, the methane emission rate from the rice field depends not only on the methane production rate in the soil, but also on the transport efficiency of the rice plant, air bubble formation that in turn depends on the production rate, and molecular diffusion. Field measurements show that methane emission rates from a particular rice field have very large diurnal, seasonal and interannual variations, which are related to soil characteristics, water regime, farming procedure, local climate, and rice growing activities. The relationship between the methane emission rate and the above mentioned factors is very complicated. The emission rates from different rice fields differ greatly not only in the absolute value, but also in the temporal variation patterns. Methane emission rate from the rice field may be significantly reduced by scientific management of fertilizer and irrigation. While the use of SO{4/2-} containing fertilizer and fermented organic fertilizer may reduce the methane emission significantly, the most promising measure for reducing methane emission from rice field is the frequent drainage irrigation procedure.

  7. Methane Ebullition in Temperate Hydropower Reservoirs and Implications for US Policy on Greenhouse Gas Emissions.

    PubMed

    Miller, Benjamin L; Arntzen, Evan V; Goldman, Amy E; Richmond, Marshall C

    2017-07-21

    The United States is home to 2198 dams actively used for hydropower production. With the December 2015 consensus adoption of the United Nations Framework Convention on Climate Change Paris Agreement, it is important to accurately quantify anthropogenic greenhouse gas emissions. Methane ebullition, or methane bubbles originating from river or lake sediments, has been shown to account for nearly all methane emissions from tropical hydropower reservoirs to the atmosphere. However, distinct ebullitive methane fluxes have been studied in comparatively few temperate hydropower reservoirs globally. This study measures ebullitive and diffusive methane fluxes from two eastern Washington reservoirs, and synthesizes existing studies of methane ebullition in temperate, boreal, and tropical hydropower reservoirs. Ebullition comprises nearly all methane emissions (>97%) from this study's two eastern Washington hydropower reservoirs to the atmosphere. Summer methane ebullition from these reservoirs was higher than ebullition in six southeastern U.S. hydropower reservoirs, however it was similar to temperate reservoirs in other parts of the world. Our literature synthesis suggests that methane ebullition from temperate hydropower reservoirs can be seasonally elevated compared to tropical climates, however annual emissions are likely to be higher within tropical climates, emphasizing the possible range of methane ebullition fluxes and the need for the further study of temperate reservoirs. Possible future changes to the Intergovernmental Panel on Climate Change and UNFCCC guidelines for national greenhouse gas inventories highlights the need for accurate assessment of reservoir emissions.

  8. What Controls Methane in Potable Ground Water in the Appalachian Basin?

    NASA Astrophysics Data System (ADS)

    Siegel, D. I.; Smith, B.; Perry, A. E.; Bothun, R.

    2014-12-01

    We present the results of baseline (pre-drilling) sampling for methane in 13,040 potable ground water samples in Northeastern Pennsylvania and 8,004 samples from a "Western Area" (southwest Pennsylvania, eastern Ohio, and north-central West Virginia) that were collected on behalf of Chesapeake Energy Corporation as part of its monitoring program prior to drilling unconventional oil and gas wells in the Marcellus and Utica Formations, as well as the results of a year-long study on temporal variability of methane in ground water at 12 locations in NE Pennsylvania We found dissolved methane common in potable ground water in the Appalachian Basin. In NE Pennsylvania, measureable dissolved methane occurred in 24% of our samples with 3.4% naturally exceeding the PADEP methane notification level of 7 mg/L. In the western area, dissolved methane occurred naturally in 36% of groundwater sampled and in Ohio, 4.1% of samples exceeded the Ohio dissolved methane action level of 10 mg/L. More methane is associated with hydrogeochemical facies trending towards Na-Cl and Na-HCO3 type waters in valleys and along hill flanks. We found no relationship occurs between the concentration of methane and proximity to pre-existing gas wells. Concentrations of methane in domestic wells can naturally vary by factors, depending on pumping regime and time of year.

  9. Testing & Research, Part I. Options in Education: Program Transcripts of a Weekly Series Broadcast by Member Stations of National Public Radio. Program No. 78.

    ERIC Educational Resources Information Center

    George Washington Univ., Washington, DC. Inst. for Educational Leadership.

    Several program transcripts on educational testing from the National Public Radio series, Options in Education, are included in this pamphlet. In "The I.Q. Controversy," Ned Block discusses culturally biased standardized tests. Dr. Harold Hodgkinson, former Director of the National Institute of Education, and Noel Epstein, Education Editor of the…

  10. Testing & Research, Part I. Options in Education: Program Transcripts of a Weekly Series Broadcast by Member Stations of National Public Radio. Program No. 78.

    ERIC Educational Resources Information Center

    George Washington Univ., Washington, DC. Inst. for Educational Leadership.

    Several program transcripts on educational testing from the National Public Radio series, Options in Education, are included in this pamphlet. In "The I.Q. Controversy," Ned Block discusses culturally biased standardized tests. Dr. Harold Hodgkinson, former Director of the National Institute of Education, and Noel Epstein, Education Editor of the…

  11. Charters, Constitutions and By-Laws of Indian Tribes of North America. Part I: The Sioux Tribes of South Dakota. Occasional Publications in Anthropology, Ethnology Series, No. 1.

    ERIC Educational Resources Information Center

    Fay, George E., Comp.

    To facilitate the study and understanding of present-day Indian tribal organization and governmental procedures, the Museum of Anthropology of the University of Northern Colorado (formerly known as Colorado State College) has assembled a large number of Indian tribal charters, constitutions, and by-laws to be reproduced as a series of…

  12. Charters, Constitutions and By-Laws of the Indian Tribes of North America; Part III: The Southwest (Apache--Mohave). Occasional Publications in Anthropology Ethnology Series No. 4.

    ERIC Educational Resources Information Center

    Fay, George E., Comp.

    The Museum of Anthropology of the University of Northern Colorado (formerly known as Colorado State College) has assembled a large number of Indian tribal charters, constitutions, and by-laws to be reproduced as a series of publications. Included in this volume are the amended charter and constitution of the Jicarilla Apache Tribe, Dulce, New…

  13. Methane emissions on large scales

    NASA Astrophysics Data System (ADS)

    Beswick, K. M.; Simpson, T. W.; Fowler, D.; Choularton, T. W.; Gallagher, M. W.; Hargreaves, K. J.; Sutton, M. A.; Kaye, A.

    Two separate studies have been undertaken to improve estimates of methane emissions on a landscape scale. The first study took place over a palsa mire in northern Finland in August 1995. A tethered balloon and a tunable diode laser were used to measure profiles of methane in the nocturnal boundary layer. Using a simple box method or the flux gradient technique fluxes ranging from 18.5 to 658 μmol m -2 h -1 were calculated. The large fluxes may be caused by advection of methane pockets across the measurement site, reflecting the heterogeneous nature of methane source strengths in the surrounding area. Under suitable conditions, comparison with nearby ground-based eddy-correlation results suggested that the balloon techniques could successfully measure fluxes on field scales. The second study was carried out by the NERC Scientific Services Atmospheric Research Airborne Support Facility using the Hercules C130 operated by the United Kingdom Meteorological Research Flight. A flight path around the northern coastline of Britain under steady West-East wind conditions enabled the measurement of methane concentrations up- and down-wind of northern Britain. Using a simple one-dimensional, constant-source diffusion model, the difference between the upwind and downwind concentrations was accounted for by methane emission from the surface. The contribution to methane emissions from livestock was also modelled. Modelled non-agricultural methane emissions decreased with increasing latitude with fluxes in northern England being a factor of 4 greater than those in northern Scotland. Since the only major methane source in northern Scotland was peat bogs, these results indicated that emissions over northern England were dominated by anthropogenic sources. Emissions from livestock accounted for 12% of the total flux over northern England, decreasing to 4% in southern Scotland and becoming negligible in northern Scotland. The total methane flux over northern Scotland was consistent

  14. Methane emissions from canopy wetlands

    NASA Astrophysics Data System (ADS)

    Martinson, G. O.; Conrad, R.

    2012-12-01

    Ground wetlands are the main natural source of methane but they fail to explain the observed amounts of methane over tropical forests. Bromeliad tanks are discrete habitats for aquatic organisms and up to several thousand of bromeliad individuals per hectare of tropical forest create a unique canopy wetland ecosystem in neotropical forests. Recently, we have discovered that canopy wetlands inhabit methanogenic archaea, emit substantial amounts of methane and may help to explain the high amounts of methane over neotropical forests. However, the pathway of methane formation and potential methane production in canopy wetlands of different tropical forest ecosystems have not yet been studied. In this study, we investigated the stable carbon isotope fractionation, methanogenic pathway and potential methane production of bromeliad tanks along an elevation gradient in neotropical forests for the first time. We sampled the bromeliad tank-substrate of 3 tank bromeliads per functional type and elevation (1000 m, 2000 m and 3000 m above the sea level). We distinguished three functional types of tank bromeliads, based on plant architecture and ecological niche preference. Functional type I-tank bromeliads are concentrated in the understory and on the ground. Functional type II and type III are concentrated in the mid and overstory. We conducted tank-substrate incubation experiments and measured CH4, CO2, 13CH4 and 13CO2 at regular time intervals during the incubation period. The methane production potential of bromeliad tanks correlated positively with tank-substrate carbon concentration and decreased with increasing canopy height and increasing elevation. The dominant pathway of methane formation in bromeliad tanks was hydrogenotrophic methanogenesis (>50%) and this dominance increased with increasing canopy height and increasing elevation. Our results provide novel insights into the pathway of methane formation in neotropical canopy wetlands and suggest that canopy height is

  15. 30 CFR 77.101 - Tests for methane and for oxygen deficiency; qualified person.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Tests for methane and for oxygen deficiency... oxygen deficiency; qualified person. (a) The provisions of Subparts C, P, R, and T of this Part 77 require that tests for methane and for oxygen deficiency be made by a qualified person. A person is...

  16. 30 CFR 77.101 - Tests for methane and for oxygen deficiency; qualified person.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Tests for methane and for oxygen deficiency... oxygen deficiency; qualified person. (a) The provisions of Subparts C, P, R, and T of this Part 77 require that tests for methane and for oxygen deficiency be made by a qualified person. A person is...

  17. 30 CFR 77.101 - Tests for methane and for oxygen deficiency; qualified person.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Tests for methane and for oxygen deficiency... oxygen deficiency; qualified person. (a) The provisions of Subparts C, P, R, and T of this Part 77 require that tests for methane and for oxygen deficiency be made by a qualified person. A person is...

  18. 30 CFR 77.101 - Tests for methane and for oxygen deficiency; qualified person.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Tests for methane and for oxygen deficiency... oxygen deficiency; qualified person. (a) The provisions of Subparts C, P, R, and T of this Part 77 require that tests for methane and for oxygen deficiency be made by a qualified person. A person is...

  19. 30 CFR 77.101 - Tests for methane and for oxygen deficiency; qualified person.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Tests for methane and for oxygen deficiency... oxygen deficiency; qualified person. (a) The provisions of Subparts C, P, R, and T of this Part 77 require that tests for methane and for oxygen deficiency be made by a qualified person. A person is...

  20. Stimulation of commercial coal seam methane production aimed at improving mining technology

    NASA Astrophysics Data System (ADS)

    Shubina, E. A.; Lukyanov, V. G.

    2016-09-01

    The relevance of the current research is due to the urgent need to revise the existing normative bases and procedures involved in intensive development of coal-methane deposits and commercial production of coal seam methane. The article presents the analysis of data on coal production volume and amount of methane emitted into the atmosphere in Kuzbass. There is a need to develop the exploration techniques that would allow implementing pre-mining gas drainage of coal seams and provide the companies with the guidance on coal seam methane drainage in very gassy coal mines. Commercial production of methane should become an integral part of economy and energy balance of the Russian Federation, which, in its turn, would enhance environmental protection due to reducing methane emissions, the largest source of greenhouse effect.

  1. Trapping of methane and ethane in Titan surface materials

    NASA Astrophysics Data System (ADS)

    Cable, M. L.; Hodyss, R. P.; Choukroun, M.; Markus, C.; Beauchamp, P. M.

    2013-12-01

    We present a series of cryogenic Raman and infrared spectra demonstrating that solid benzene (as well as other putative Titan surface materials) can trap significant amounts of ethane and methane within its crystal structure at Titan surface temperatures. This is analogous to the well-known ability of water ice to trap volatile species well above their sublimation temperatures (e.g., Bar-Nun et al. 1985 , Icarus, 63, 317). Experiments also suggest that liquid ethane can permeate and adsorb onto solid benzene, implying that lake edges and evaporite basins on Titan may hold important quantities of ethane. These results can help explain the release of methane observed at the Huygens landing site (Nieman et al. 2010, JGR 115, E12006), and point toward a large possible reservoir of methane and ethane hidden within Titan's surface organics.

  2. PACE. A Program for Acquiring Competence in Entrepreneurship. Part III: Being an Entrepreneur. Unit E: Successful Selling. Research and Development Series No. 194 C-5.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    This three-part curriculum for entrepreneurship education is primarily for postsecondary level, including four-year colleges and adult education, but it can be adapted for special groups or vocational teacher education. The emphasis of the eight instructional units in Part III is operating a business. Unit E focuses on personal (face-to-face)…

  3. PACE. A Program for Acquiring Competence in Entrepreneurship. Part II: Becoming an Entrepreneur. Unit C: Legal Issues and Small Business. Research and Development Series No. 194 B-3.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    This three-part curriculum for entrepreneurship education is primarily for postsecondary level, including four-year colleges and adult education, but it can be adapted for special groups or vocational teacher education. The emphasis of the seven instructional units in Part II is establishing a business. Unit C focuses on legal issues that affect…

  4. PACE. A Program for Acquiring Competence in Entrepreneurship. Part III: Being an Entrepreneur. Unit C: Keeping the Business Records. Research and Development Series No. 194 C-3.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    This three-part curriculum for entrepreneurship education is primarily for postsecondary level, including four-year colleges and adult education, but can be adapted for special groups or vocational teacher education. The emphasis of the eight instructional units in Part II is operating a business. Unit C focuses on record keeping. It introduces…

  5. PACE. A Program for Acquiring Competence in Entrepreneurship. Part III: Being an Entrepreneur. Unit D: Marketing Management. Research and Development Series No. 194 C-4.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    This three-part curriculum for entrepreneurship education is primarily for postsecondary level, including four-year colleges and adult education, but it can be adapted for special groups or vocational teacher education. The emphasis of the eight instructional units in Part III is operating a business. Unit D focuses on market management. It…

  6. PACE. A Program for Acquiring Competence in Entrepreneurship. Part III: Being an Entrepreneur. Unit A: Managing the Business. Research and Development Series No. 194 C-1.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    This three-part curriculum for entrepreneurship education is primarily for postsecondary level, including four-year colleges and adult education, but it can be adapted for special groups or vocational teacher education. The emphasis of the eight instructional units in Part III is operating a business. Unit A focuses on the management process. It…

  7. PACE. A Program for Acquiring Competence in Entrepreneurship. Part II: Becoming an Entrepreneur. Unit B: Where to Locate the Business. Research and Development Series No. 194 B-2.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    This three-part curriculum for entrepreneurship education is primarily for postsecondary level, including four-year colleges and adult education, but it can be adapted for special groups or vocational teacher education. The emphasis of the seven instructional units in Part II is on establishing a business. Unit B focuses on choosing a business…

  8. PACE. A Program for Acquiring Competence in Entrepreneurship. Part II: Becoming an Entrepreneur. Unit G: Resources for Managerial Assistance. Research and Development Series No. 194 B-7.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    This three-part curriculum for entrepreneurship education is primarily for postsecondary level, including four-year colleges and adult education, but it can be adapted for special groups or vocational teacher education. The emphasis of the seven instructional units in Part II is establishing business. Unit G focuses on obtaining managerial…

  9. PACE. A Program for Acquiring Competence in Entrepreneurship. Part III: Being an Entrepreneur. Unit H: Business Protection. Research and Development Series No. 194 C-8.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    This three-part curriculum for entrepreneurship education is primarily for postsecondary level, including four-year colleges and adult education, but it can be adapted for special groups or vocational teacher education. The emphasis of the eight instructional units in part III is operating a business. Unit H focuses on business protection. It…

  10. PACE. A Program for Acquiring Competence in Entrepreneurship. Part II: Becoming an Entrepreneur. Unit E: Choosing the Type of Ownership. Research and Development Series No. 194 B-5.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    This three-part curriculum for entrepreneurship education is primarily for postsecondary level, including four-year colleges and adult education, but it can be adapted for special groups or vocational teacher education. The emphasis of the seven instructional units in Part II is establishing a business. Unit E focuses on the three major types of…

  11. Seasonal and inter-annual variation in ecosystem scale methane emission from a boreal fen

    NASA Astrophysics Data System (ADS)

    Rinne, Janne; Li, Xuefei; Raivonen, Maarit; Peltola, Olli; Sallantaus, Tapani; Haapanala, Sami; Smolander, Sampo; Alekseychik, Pavel; Aurela, Mika; Korrensalo, Aino; Mammarella, Ivan; Tuittila, Eeva-Stiina; Vesala, Timo

    2016-04-01

    Northern wetlands are one of the major sources of atmospheric methane. We have measured ecosystem scale methane emissions from a boreal fen continuously since 2005. The site is an oligotrophic fen in boreal vegetation zone situated in Siikaneva wetland complex in Southern Finland. The mean annual temperature in the area is 3.3°C and total annual precipitation 710 mm. We have conducted the methane emission measurements by the eddy covariance method. Additionally we have measured fluxes of carbon dioxide, water vapor, and sensible heat together with a suite of other environmental parameters. We have analyzed this data alongside with a model run with University of Helsinki methane model. The measured fluxes show generally highest methane emission in late summers coinciding with the highest temperatures in saturated peat zone. During winters the fluxes show small but detectable emission despite the snow and ice cover on the fen. More than 90% of the annual methane emission occurs in snow-free period. The methane emission and peat temperature are connected in exponential manner in seasonal scales, but methane emission does not show the expected behavior with water table. The lack of water table position dependence also contrasts with the spatial variation across microtopography. There is no systematic variation in sub-diurnal time scale. The general seasonal cycle in methane emission is captured well with the methane model. We will show how well the model reproduces the temperature and water table position dependencies observed. The annual methane emission is typically around 10 gC m-2. This is a significant part of the total carbon exchange between the fen and the atmosphere and about twice the estimated carbon loss by leaching from the fen area. The inter-annual variability in the methane emission is modest. The June-September methane emissions from different years, comprising most of the annual emission, correlates positively with peat temperature, but not with

  12. Diverse origins of Arctic and Subarctic methane point source emissions identified with multiply-substituted isotopologues

    NASA Astrophysics Data System (ADS)

    Douglas, P. M. J.; Stolper, D. A.; Smith, D. A.; Walter Anthony, K. M.; Paull, C. K.; Dallimore, S.; Wik, M.; Crill, P. M.; Winterdahl, M.; Eiler, J. M.; Sessions, A. L.

    2016-09-01

    Methane is a potent greenhouse gas, and there are concerns that its natural emissions from the Arctic could act as a substantial positive feedback to anthropogenic global warming. Determining the sources of methane emissions and the biogeochemical processes controlling them is important for understanding present and future Arctic contributions to atmospheric methane budgets. Here we apply measurements of multiply-substituted isotopologues, or clumped isotopes, of methane as a new tool to identify the origins of ebullitive fluxes in Alaska, Sweden and the Arctic Ocean. When methane forms in isotopic equilibrium, clumped isotope measurements indicate the formation temperature. In some microbial methane, however, non-equilibrium isotope effects, probably related to the kinetics of methanogenesis, lead to low clumped isotope values. We identify four categories of emissions in the studied samples: thermogenic methane, deep subsurface or marine microbial methane formed in isotopic equilibrium, freshwater microbial methane with non-equilibrium clumped isotope values, and mixtures of deep and shallow methane (i.e., combinations of the first three end members). Mixing between deep and shallow methane sources produces a non-linear variation in clumped isotope values with mixing proportion that provides new constraints for the formation environment of the mixing end-members. Analyses of microbial methane emitted from lakes, as well as a methanol-consuming methanogen pure culture, support the hypothesis that non-equilibrium clumped isotope values are controlled, in part, by kinetic isotope effects induced during enzymatic reactions involved in methanogenesis. Our results indicate that these kinetic isotope effects vary widely in microbial methane produced in Arctic lake sediments, with non-equilibrium Δ18 values spanning a range of more than 5‰.

  13. A Methane Balloon Inflation Chamber

    ERIC Educational Resources Information Center

    Czerwinski, Curtis J.; Cordes, Tanya J.; Franek, Joe

    2005-01-01

    The various equipments, procedure and hazards in constructing the device for inflating a methane balloon using a standard methane outlet in a laboratory are described. This device is fast, safe, inexpensive, and easy to use as compared to a hydrogen gas cylinder for inflating balloons.

  14. A Methane Balloon Inflation Chamber

    ERIC Educational Resources Information Center

    Czerwinski, Curtis J.; Cordes, Tanya J.; Franek, Joe

    2005-01-01

    The various equipments, procedure and hazards in constructing the device for inflating a methane balloon using a standard methane outlet in a laboratory are described. This device is fast, safe, inexpensive, and easy to use as compared to a hydrogen gas cylinder for inflating balloons.

  15. Continuous catalytic decomposition of methane

    NASA Technical Reports Server (NTRS)

    Clifford, J. E.; Hillenbrand, L. J.; Kim, B. C.; Kolic, E. S.; Zupan, J.

    1973-01-01

    Water is conserved by employing sequence of reactions whereby 75 percent of methane from Sabatier reaction is decomposed to solid carbon and hydrogen; hydrogen is then separated from residual methane and utilized in usual Sabatier reaction to reduce remaining metabolic carbon dioxide.

  16. Methane in the Baltic and North Seas and a reassessment of the marine emissions of methane

    SciTech Connect

    Bange, H.W.; Bartell, U.H.; Rapsomanikis, S.

    1994-12-01

    During three measurement campaigns on the Baltic and North Seas, atmospheric and dissolved methane was determined with an automated gas chromatographic system. Area-weighted mean saturation values in the sea surface waters were 113{+-}5% and 395{+-}82% and 126{+-}8%. On the bases of our data and a compilation of literature data the global oceanic emissions of methane were reassessed by introducing a concept of regional gas transfer coefficients. Our estimates computed with two different air-sea exchange models lie in the range of 11-18 Tg CH{sub 4} yr{sup -1}. Despite the fact that shelf areas and estuaries only represent a small part of the world`s ocean they contribute about 75% to the global oceanic emissions. We applied a simple, coupled, three-layer model to evaluate the time dependent variation of the oceanic flux to the atmosphere. The model calculations indicate that even with increasing tropospheric methane concentration, the ocean will remain a source of atmospheric methane. 72 refs., 7 figs., 7 tabs.

  17. Methane dynamics regulated by microbial community response to permafrost thaw.

    PubMed

    McCalley, Carmody K; Woodcroft, Ben J; Hodgkins, Suzanne B; Wehr, Richard A; Kim, Eun-Hae; Mondav, Rhiannon; Crill, Patrick M; Chanton, Jeffrey P; Rich, Virginia I; Tyson, Gene W; Saleska, Scott R

    2014-10-23

    Permafrost contains about 50% of the global soil carbon. It is thought that the thawing of permafrost can lead to a loss of soil carbon in the form of methane and carbon dioxide emissions. The magnitude of the resulting positive climate feedback of such greenhouse gas emissions is still unknown and may to a large extent depend on the poorly understood role of microbial community composition in regulating the metabolic processes that drive such ecosystem-scale greenhouse gas fluxes. Here we show that changes in vegetation and increasing methane emissions with permafrost thaw are associated with a switch from hydrogenotrophic to partly acetoclastic methanogenesis, resulting in a large shift in the δ(13)C signature (10-15‰) of emitted methane. We used a natural landscape gradient of permafrost thaw in northern Sweden as a model to investigate the role of microbial communities in regulating methane cycling, and to test whether a knowledge of community dynamics could improve predictions of carbon emissions under loss of permafrost. Abundance of the methanogen Candidatus 'Methanoflorens stordalenmirensis' is a key predictor of the shifts in methane isotopes, which in turn predicts the proportions of carbon emitted as methane and as carbon dioxide, an important factor for simulating the climate feedback associated with permafrost thaw in global models. By showing that the abundance of key microbial lineages can be used to predict atmospherically relevant patterns in methane isotopes and the proportion of carbon metabolized to methane during permafrost thaw, we establish a basis for scaling changing microbial communities to ecosystem isotope dynamics. Our findings indicate that microbial ecology may be important in ecosystem-scale responses to global change.

  18. Coal mine methane global review

    SciTech Connect

    2008-07-01

    This is the second edition of the Coal Mine Methane Global Overview, updated in the summer of 2008. This document contains individual, comprehensive profiles that characterize the coal and coal mine methane sectors of 33 countries - 22 methane to market partners and an additional 11 coal-producing nations. The executive summary provides summary tables that include statistics on coal reserves, coal production, methane emissions, and CMM projects activity. An International Coal Mine Methane Projects Database accompanies this overview. It contains more detailed and comprehensive information on over two hundred CMM recovery and utilization projects around the world. Project information in the database is updated regularly. This document will be updated annually. Suggestions for updates and revisions can be submitted to the Administrative Support Group and will be incorporate into the document as appropriate.

  19. Lead optimization of the VU0486321 series of mGlu1 PAMs. Part 1: SAR of modifications to the central aryl core.

    PubMed

    Garcia-Barrantes, Pedro M; Cho, Hyekyung P; Blobaum, Anna L; Niswender, Colleen M; Conn, P Jeffrey; Lindsley, Craig W

    2015-11-15

    This Letter describes the lead optimization of the VU0486321 series of mGlu1 positive allosteric modulators (PAMs). While first generation PAMs from Roche were reported in the late 1990s, little effort has focused on the development of mGlu1 PAMs since. New genetic data linking loss-of-function mutant mGlu1 receptors to schizophrenia, bipolar disorder and other neuropsychiatric disorders has rekindled interest in the target, but the ideal in vivo probe, for example, with good PK, brain penetration and low plasma protein binding, for robust target validation has been lacking. Here we describe the first modifications to the central aryl core of the VU0486321 series, where robust SAR was noted. Moreover, structural variants were identified that imparted selectivity (up to >793-fold) versus mGlu4.

  20. Renewed methane increase (2007-2014): contribution of oil and natural gas emissions determined from methane and ethane column observations

    NASA Astrophysics Data System (ADS)

    Hausmann, Petra; Sussmann, Ralf; Smale, Dan

    2016-04-01

    Harmonized time series of column-averaged mole fractions of atmospheric methane and ethane over the period 1999-2014 are derived from solar Fourier transform infrared (FTIR) measurements at the Zugspitze summit (47° N, 2964 m a.s.l.) and at Lauder (45° S, 370 m a.s.l.). Long-term trend analysis reveals a consistent renewed methane increase since 2007 of 6.2 [5.6, 6.9] ppb yr-1 at the Zugspitze and 6.0 [5.3, 6.7] ppb yr-1 at Lauder (95 % confidence intervals). Several recent studies provide pieces of evidence that the renewed methane increase is most likely driven by two main factors: (i) increased methane emissions from tropical wetlands, followed by (ii) increased thermogenic methane emissions due to growing oil and natural gas production. Here, we quantify the magnitude of the second class of sources, using long-term measurements of atmospheric ethane as tracer for thermogenic methane emissions. In 2007, after years of weak decline, the Zugspitze ethane time series shows the sudden onset of a significant positive trend (2.3 [1.8, 2.8] × 10-2 ppb yr-1 for 2007-2014), while a negative trend persists at Lauder after 2007 (-0.4 [-0.6, -0.1] × 10-2 ppb yr-1). Zugspitze methane and ethane time series are significantly correlated for the period 2007-2014 and can be assigned to thermogenic methane emissions with an ethane-to-methane ratio of 10-21 %. We present optimized emission scenarios for 2007-2014 derived from an atmospheric two-box model. From our trend observations we infer a total ethane emission increase over the period 2007-2014 from oil and natural gas sources of 1-11 Tg yr-1 along with an overall methane emission increase of 24-45 Tg yr-1. Based on these results, the oil and natural gas emission contribution C to the renewed methane increase is deduced using three different emission scenarios with dedicated ranges of methane-to-ethane ratios (MER). Reference scenario 1 assumes an oil and gas emission combination with MER = 3.3-7.6, which results in a

  1. Lead optimization of the VU0486321 series of mGlu1 PAMs. Part 3. Engineering plasma stability by discovery and optimization of isoindolinone analogs.

    PubMed

    Garcia-Barrantes, Pedro M; Cho, Hyekyung P; Blobaum, Anna L; Niswender, Colleen M; Conn, P Jeffrey; Lindsley, Craig W

    2016-04-15

    This Letter describes the further lead optimization of the VU0486321 series of mGlu1 positive allosteric modulators (PAMs), focused on addressing the recurrent issue of plasma instability of the phthalimide moiety. Here, we evaluated a number of phthalimide bioisosteres, and ultimately identified isoindolinones as the ideal replacement that effectively address plasma instability, while maintaining acceptable mGlu1 PAM potency, DMPK profile, CNS penetration and mGluR selectivity.

  2. A controlled time-series trial of clinical reminders: using computerized firm systems to make quality improvement research a routine part of mainstream practice.

    PubMed Central

    Goldberg, H. I.; Neighbor, W. E.; Cheadle, A. D.; Ramsey, S. D.; Diehr, P.; Gore, E.

    2000-01-01

    OBJECTIVE: To explore the feasibility of conducting unobtrusive interventional research in community practice settings by integrating firm-system techniques with time-series analysis of relational-repository data. STUDY SETTING: A satellite teaching clinic divided into two similar, but geographically separated, primary care group practices called firms. One firm was selected by chance to receive the study intervention. Forty-two providers and 2,655 patients participated. STUDY DESIGN: A nonrandomized controlled trial of computer-generated preventive reminders. Net effects were determined by quantitatively combining population-level data from parallel experimental and control interrupted time series extending over two-month baseline and intervention periods. DATA COLLECTION: Mean rates at which mammography, colorectal cancer screening, and cholesterol testing were performed on patients due to receive each maneuver at clinic visits were the trial's outcome measures. PRINCIPAL FINDINGS: Mammography performance increased on the experimental firm by 154 percent (0.24 versus 0.61, p = .03). No effect on fecal occult blood testing was observed. Cholesterol ordering decreased on both the experimental (0.18 versus 0.1 1, p = .02) and control firms (0.13 versus 0.07, p = .03) coincident with national guidelines retreating from recommending screening for young adults. A traditional uncontrolled interrupted time-series design would have incorrectly attributed the experimental-firm decrease to the introduction of reminders. The combined analysis properly indicated that no net prompting effect had occurred, as the difference between firms in cholesterol testing remained stochastically stable over time (0.05 versus 0.04, p = .75). A logistic-regression analysis applied to individual-level data produced equivalent findings. The trial incurred no supplementary data collection costs. CONCLUSIONS: The apparent validity and practicability of our reminder implementation study should

  3. Impact of changes in barometric pressure on landfill methane emission

    NASA Astrophysics Data System (ADS)

    Xu, Liukang; Lin, Xiaomao; Amen, Jim; Welding, Karla; McDermitt, Dayle

    2014-07-01

    Landfill methane emissions were measured continuously using the eddy covariance method from June to December 2010. The study site was located at the Bluff Road Landfill in Lincoln, Nebraska, USA. Our results show that landfill methane emissions strongly depended on changes in barometric pressure; rising barometric pressure suppressed the emission, while falling barometric pressure enhanced the emission, a phenomenon called barometric pumping. There was up to a 35-fold variation in day-to-day methane emissions due to changes in barometric pressure. Wavelet coherence analysis revealed a strong spectral coherency between variations of barometric pressure and methane emission at periodicities ranging from 1 day to 8 days. Power spectrum and ogive analysis showed that at least 10 days of continuous measurements was needed in order to capture 90% of the total variance in the methane emission time series at our landfill site. From our results, it is clear that point-in-time measurements taken at monthly or longer time intervals using techniques such as the trace plume method, the mass balance method, or the closed-chamber method will be subject to large variations in measured emission rates because of the barometric pumping phenomenon. Estimates of long-term integrated methane emissions from landfills based on such measurements could yield uncertainties, ranging from 28.8% underestimation to 32.3% overestimation. Our results demonstrate a need for continuous measurements to quantify annual total landfill emissions. This conclusion may apply to the study of methane emissions from wetlands, peatlands, lakes, and other environmental contexts where emissions are from porous media or ebullition. Other implications from the present study for hazard gas monitoring programs are also discussed.

  4. Successional Change in Methane Dynamics Along a Mire Chronosequence

    NASA Astrophysics Data System (ADS)

    Tuittila, E.; Leppala, M.; Laine, J.; Kukko-Oja, K.; Yrjala, K.; Fritze, H.; Merila, P.

    2006-12-01

    Northern mires are one of the major sources of methane into the atmosphere. However, the variation in methane dynamics between different mires is considerable and the magnitude of methane emission from mire ecosystems is closely linked to their plant community composition. In mires, there is a successional pattern in vegetation where sedge dominated fen communities are gradually replaced by Sphagnum dominated bog communities. We hypothesized that during mire succession there is a change in methane dynamics that follows the change in plant communities providing substrate for methanogenesis. In the coastal area of the Gulf of Bothnia between Finland and Sweden, new land is continuously exposed due to the ongoing post-glacial rebound (8-9 mm yr-1). Consequently, it is possible to find a primary successional series of undisturbed mire ecosystems where the changes in vegetation and carbon dynamics are driven by natural autogenic succession. We studied methane dynamics in this landscape over a 8 km long chronosequence transect of five mires, with ages varying from a few to approximately 2500 years. We applied chamber technique. Our study period covered a dry and a rainy growing season. During the dry summer 2003 three youngest sites acted as small sinks for methane and only the two oldest ones were net emitters. In the following wetter year 2004 all the sites turned to methane sources. In contrast to the younger sites where the average emission varied from around - 1 in 2003 to + 60 mg CH4 m-2 d-1 in 2004, the emission from the two oldest sites stayed at the same level, around 90 mg CH4 m-2 d-1. In contrast to our hypothesis, methane dynamics did not directly follow the successional pattern in vegetation. In the two youngest mires vegetation is meadowlike and the oldest one is a mosaic of fen and bog vegetation, with cottongrass and Sphagnum species. Two intermediate sites that differed in their methane dynamics are both fens characterized by sedges and Sphagnum species

  5. Methane Emissions from Upland Trees

    NASA Astrophysics Data System (ADS)

    Pitz, S.; Megonigal, P.; Schile, L. M.; Szlavecz, K. A.; King, K.

    2013-12-01

    Most work on methane (CH4) emissions from natural ecosystems has focused on wetlands and wetland soils because they are predictable emitters and relatively simple to quantify. Less attention has been directed toward upland ecosystems that cover far larger areas, but are assumed to be too dry to emit CH4. There is abundant evidence that upland ecosystems emit small amounts of CH4 during hot moments that collectively constitute a significant source in the global budget of this potent greenhouse gas. We have established two transects across natural moisture gradients in two forests near Annapolis, Maryland. Both tree and soil methane fluxes were measured using chamber methods. Each tree chamber was custom fit to the stem near the base. In addition, porewater methane concentrations were collected at multiple depths near trees. Abiotic parameters such as soil temperature, soil moisture, water potential, and depth to groundwater were monitored using a wireless sensor network. Upland emissions from tree stems were as high as 14.6 umoles CH4 m-2 hr-1 while the soil uptake was -1.5 umoles CH4 m-2 hr-1. These results demonstrate that tree methane emissions and soil methane uptake can occur simultaneously in a mesic forest. Factors controlling methane emissions were soil temperature, soil moisture, and depth to groundwater. Based on our preliminary data, tree mediated methane emissions may be offsetting the soil methane sink of upland forests by 20 to 30%. Future methane budgets and climate models will need to include tree fluxes and the parameters that control methane emissions for accurate accounting and predictions.

  6. Biogenic methane leakage on the Aquitaine Shelf: fluid system characterization from source to emission

    NASA Astrophysics Data System (ADS)

    Michel, Guillaume; Dupré, Stéphanie; Baltzer, Agnès; Imbert, Patrice; Ehrhold, Axel; Battani, Anne; Deville, Eric

    2017-04-01

    The recent discovery of biogenic methane emissions associated with methane-derived authigenic carbonate mounds along the Aquitaine Shelf edge offshore SW France (140 to 220 m water depth) questions about the initiation and temporal evolution of this fluid system (80 km N-S and 8 km E-W). Based on a multi-data study (including multibeam echosounder, subbottom profiler, single channel sparker seismic, 80 traces air gun seismic data and well cuttings and logs), different scenarii are proposed for the organic matter source levels and migration pathways of the methane. Several evidence of the presence of gas are observed on seismic data and interpreted to be linked to the biogenic system. Single channel sparker seismic lines exhibit an acoustic blanking (between 75-100 ms TWT below seafloor and the first multiple) below the present-day seepage area and westwards up to 8 km beyond the shelf-break. An air gun seismic line exhibits chaotic reflections along 8 km below the seepage area from the seabed down to 700 ms TWT below seafloor. Based on 1) the local geothermal gradient about 26 °C/km and 2) the window for microbial methanogenesis ranging from 4 to 56 °C, the estimation of the bottom limit for biogenic generation window is about 1.5 km below seafloor. Cuttings from 3 wells of the area within the methanogenesis window show average TOC (Total Organic Carbon) of 0.5 %; however, one well shows some coal levels with 30-35 % TOC in the Oligocene between 1490 and 1540 m below seafloor. Geochemical analysis on crushed cuttings evidenced heavy hydrocarbons up to mid-Paleogene, while shallower series did not evidence any. In the first scenario, we propose that methane is sourced from the Neogene prograding system. The 0.5% average TOC is sufficient to generate a large volume of methane over the thickness of this interval (up to 1 km at the shelf break area). In the second scenario, methane would be sourced from the Oligocene coals; however their spatial extension with regard

  7. Urban - Wetland contrast in turbulent exchange of methane

    NASA Astrophysics Data System (ADS)

    Pawlak, Włodzimierz; Fortuniak, Krzysztof; Siedlecki, Mariusz; Zieliński, Mariusz

    2016-11-01

    Continuous eddy-covariance measurements of turbulent methane exchange between the ground and the atmosphere were carried out during the period from July 2013 to September 2015. The measurement sites were located in areas characterized by different types of use: the city (Łódź, central Poland) and the wetlands of Biebrza National Park (northeastern Poland). Regardless of the type of surface, such long-term, continuous measurements of the turbulent fluxes of methane are rare. Our aim was to investigate the temporal variability of the turbulent methane exchange in the surface-atmosphere system, while considering the impact of land use. Because cities are a huge source of atmospheric carbon dioxide, we compared the intensity of methane emissions from the city as compared to the wetland, which is considered to be the most intense natural source atmospheric methane. In both cases, the results show a clear prevalence of positive as compared with negative fluxes. This shows that both areas are net sources of methane to the troposphere. The measurements also demonstrated the existence of a clear annual cycle of turbulent methane flux in the centre of the city (average values in winter ranged from ∼40 to 60 nmol m-2·s-1 and were significantly greater than values measured in summer) as well as in the wetlands, where maximum values were observed during the warm part of the year (approximately 80 nmol m-2·s-1 or more). The different times of maximum CH4 flux (FCH4) occurrence resulted from the differentiation of processes that determine methane emissions: in the city these are anthropogenic emissions (strongest in winter); in the wetland, natural processes dominate. The diurnal variability of FCH4 was faintly detectable, except for the cold half of the year in the city and the warm half of the year in the wetland. The studied area of the centre of Łódź, in turn, is also characterized by a weekly cycle of methane exchange: the values measured on working days were

  8. Reactor for methane conversion

    SciTech Connect

    Bader, R.A.; Axelrod, M.G.

    1989-08-08

    This patent describes a reactor adapted for the conversion of methane to higher molecular weight hydrocarbons. It comprises a central support column and an outer shell which together define an annular reaction zone, inlet means for introducing a mixture of methane containing gas and fluidized solid catalyst particles into the reaction zone, and outlet means for withdrawing a mixture of gas and fluidized solid catalyst particles from the zone, and a plurality of vertically spaced ceramic baffle assemblies comprised of wedged-shaped segments positioned in the reaction zone each perpendicular to the central support column and the outer shell. The baffle assemblies filling the annular cross-section between the support column and the outer shell and being supported at the outer wall of the central support column and at the inner wall of the outer shell, adjacent baffle assembly segments also being supported by radial ceramic support beams. The baffle assemblies each having a plurality of openings 0.25 to 3 inches in diameter adapted to permit passage of the mixture of gas and fluidized solid catalyst particles through the baffle assemblies only toward the outlet means, the area of the openings being 10-70% of the baffle area of each baffle assembly.

  9. Making methane visible

    NASA Astrophysics Data System (ADS)

    Gålfalk, Magnus; Olofsson, Göran; Crill, Patrick; Bastviken, David

    2016-04-01

    Methane (CH4) is one of the most important greenhouse gases, and an important energy carrier in biogas and natural gas. Its large scale emission patterns have been unpredictable and the source and sink distributions are poorly constrained. Remote assessment of CH4 with high sensitivity at m2 spatial resolution would allow detailed mapping of near ground distribution and anthropogenic sources and sinks in landscapes but has hitherto not been possible. Here we show that CH4 gradients can be imaged on methane imaging will include a lake, barn, sewage sludge deposit, waste incineration plant, and controlled gas releases. We will also present successful simultaneous imaging of another important greenhouse gas, nitrous oxide, with the same instrument.

  10. Carbon fibre composite for ventilation air methane (VAM) capture.

    PubMed

    Thiruvenkatachari, Ramesh; Su, Shi; Yu, Xin Xiang

    2009-12-30

    Coal mine methane (CMM) is not only a hazardous greenhouse gas but is also a wasted energy resource, if not utilised. This paper evaluates a novel adsorbent material developed for capturing methane from ventilation air methane (VAM) gas in underground coal mines. The adsorbent material is a honeycomb monolithic carbon fibre composite (HMCFC) consisting of multiple parallel flow-through channels and the material exhibits unique features including low pressure drop, good mechanical properties, ability to handle dust-containing gas streams, good thermal and electrical conductivity and selective adsorption of gases. During this study, a series of HMCFC adsorbents (using different types of carbon fibres) were successfully fabricated. Experimental data demonstrated the proof-of-concept of using the HMCFC adsorbent to capture methane from VAM gas. The adsorption capacity of the HMCFC adsorbent was twice that of commercial activated carbon. Methane concentration of 0.56% in the inlet VAM gas stream is reduced to about 0.011% after it passes through the novel carbon fibre composite adsorbent material at ambient temperature and atmospheric pressure. This amounts to a maximum capture efficiency of 98%. These encouraging laboratory scale studies have prompted further large scale trials and economic assessment.

  11. Hydroxylation of methane through component interactions in soluble methane monooxygenases.

    PubMed

    Lee, Seung Jae

    2016-04-01

    Methane hydroxylation through methane monooxygenases (MMOs) is a key aspect due to their control of the carbon cycle in the ecology system and recent applications of methane gas in the field of bioenergy and bioremediation. Methanotropic bacteria perform a specific microbial conversion from methane, one of the most stable carbon compounds, to methanol through elaborate mechanisms. MMOs express particulate methane monooxygenase (pMMO) in most strains and soluble methane monooxygenase (sMMO) under copper-limited conditions. The mechanisms of MMO have been widely studied from sMMO belonging to the bacterial multicomponent monooxygenase (BMM) superfamily. This enzyme has diiron active sites where different types of hydrocarbons are oxidized through orchestrated hydroxylase, regulatory and reductase components for precise control of hydrocarbons, oxygen, protons, and electrons. Recent advances in biophysical studies, including structural and enzymatic achievements for sMMO, have explained component interactions, substrate pathways, and intermediates of sMMO. In this account, oxidation of methane in sMMO is discussed with recent progress that is critical for understanding the microbial applications of C-H activation in one-carbon substrates.

  12. Environmental Controls on Aerobic Methane Oxidation in Coastal Waters

    NASA Astrophysics Data System (ADS)

    Steinle, L.; Maltby, J.; Engbersen, N.; Zopfi, J.; Bange, H. W.; Elvert, M.; Hinrichs, K. U.; Kock, A.; Lehmann, M. F.; Treude, T.; Niemann, H.

    2015-12-01

    Large quantities of the greenhouse gas CH4 are produced in anoxic sediments of continental margins and may be liberated to the overlying water column, and later into the atmosphere. Indeed, coastal seas account for more than 75% of global oceanic CH4 emissions. Yet, aerobic CH4 oxidizing bacteria (MOB) consume an important part of CH4 in the water column, thus mitigating CH4 release to the atmosphere. Coastal oceans are highly dynamic systems, in particular with regard to the variability of temperature, salinity and oxygen concentrations, all of which are potential key environmental factors controlling MOx. To determine the most important controlling factors, we conducted a two-year time-series study with measurements of CH4, MOx, the composition of the MOB community, and physicochemical water column parameters in a coastal inlet in the Baltic Sea (Eckernförde(E-) Bay, Boknis Eck Time Series Station). In addition, we investigated the influence of temperature and oxygen on MOx during controlled laboratory experiments. In E-Bay, seasonal stratification leads to hypoxia in bottom waters towards the end of the stratification period. Methane is produced year-round in the sediments, resulting in accumulation of methane in bottom waters, and supersaturation (with respect to the atmospheric equilibrium) in surface waters. Here, we will discuss the factors impacting MOx the most, which were a) perturbations of the water column caused by storm events, currents or seasonal mixing, b) temperature and c) oxygen concentration. a) Perturbations of the water column led to a sharp decrease in MOx within hours, probably caused by replacement of 'old' water with a high standing stock of MOB by 'new' waters with a lower abundance of MOB. b) An increase in temperature generally led to higher MOx rates. c) Even though CH4 was abundant at all depths, MOx was highest in bottom waters (1-5 nM/d), which usually contain the lowest O2 concentrations. Lab-based experiments with adjusted O2

  13. Dissolved methane in the residual basins of the Aral Sea

    NASA Astrophysics Data System (ADS)

    Izhitskaya, Elena; Zavialov, Peter; Egorov, Alexander

    2017-04-01

    The state of the Aral Sea has changed significantly since the second half of the 20th century. Due to the level decline the present-day sea consists of the several water bodies: the Large Aral Sea, the Small Aral Sea and Lake Tshchebas. Water balance peculiarities of each basin caused the differences in physical, chemical and biological structure of the ecosystem. Severe salinization of the Large Aral resulted in the increase of water stratification and formation of the anoxic conditions in the bottom layer. According to the field survey of 2002 [Zavialov et al., 2003; Friedrich, Oberhansli, 2004], hydrogen sulfide was detected in the bottom layer of the Large Aral Sea for the first time. Methane formation is the next reaction after sulfate reduction within process of sequential oxidation of organic matter [Break, 1974]. Thus, methane is an important indicator of biogeochemical processes in natural water environments. Besides due to high greenhouse activity of methane study of its emission to the atmosphere is essential for solution of climatological problems [Bazhin, 2000]. The presented study aims to the evaluation of methane dissolved in waters of the Aral region. Measurements of the gas concentration were carried out on surface and vertical profiles, as well as on point stations in 2012, 2013, 2015 and 2016 years in different parts of the sea. Water samples were analyzed by the head-space method with further gas chromatographic determination of methane concentration [Bolshakov, Egorov, 1987]. According to the obtained data, dissolved methane content in the surface waters of the residual basins of the Aral Sea ranges from 12 to 234 nM/l. One of the main results of the research is detection of intensive methane increase in the lower water layer of the Large Aral to 17014 nM/l in central part and to 147316 nM/l in the Chernyshev Bay.

  14. [Biogeochemical cycle of methane in the northwestern shelf of the Black Sea].

    PubMed

    Rusanov, I I; Levi, A Iu; Pimenov, N V; Iusupov, S K; Ivanov, M V

    2002-01-01

    Seasonal investigations of methane distribution and rates of its oxidation and generation in the water column and sediments of the Black Sea northwestern shelf were carried out within the framework of the interdisciplinary projects "European River-Ocean Systems" (EROS-2000, EROS-21) and "Biogenic Gases Exchange in the Black Sea" (BigBlack) in August 1995, May 1997, and December 1999. Experiments that involved the addition of 14CH3COONa and 14CO2 to sediment samples showed the main part of methane to be formed from CO2. Maximum values of methane production (up to 559 mumol/(m2 day)) were found in coastal sediments in summer time. In winter and spring, methane production in the same sediments did not exceed 3.6-4.2 mumol/(m2 day). The delta 13C values of methane ranged from -70.7 to -81.8@1000, demonstrating its microbial origin and contradicting the concept of the migration of methane from cold seeps or from the oil fields located at the Black Sea shelf. Experiments that involved the addition of 14CH4 to water and sediment samples showed that a considerable part of methane is oxidized in the upper horizons of bottom sediments and in the water column. Nevertheless, it was found that, in summer, part of methane (from 6.8 to 320 mumol/(m2 day)) arrives in the atmosphere.

  15. Possible relation between methane seeps at shelf-edge pockmarks and downslope methane hydrates off North Carolina and Virginia

    NASA Astrophysics Data System (ADS)

    Johnson, H. E.; Cormier, M.; Kelley, C. A.; Gardner, J. M.; Hagen, R. A.

    2011-12-01

    Water column data collected from an AUV and from shipboard hydrocasts document that methane-rich fluids are actively seeping at a series of kilometer-scale pockmarks near the shelf break offshore North Carolina and Virginia. Reprocessing of multibeam bathymetric sonar data further documents an intermittent bubble plume at the site of the highest dissolved methane concentrations. Gas plumes are also detected on the adjacent shelf from newly collected subbottom seismic profiling (CHIRP) data. However, the origin of this methane remains controversial. Although it is associated with fresher, colder water and water chemistry indicates it is biogenic in origin, these characteristics fit two models equally well. In the first one, methane is sourced from the dissociation of gas hydrates down the continental slope, triggered by post-glacial introduction of warm Gulf Stream bottom water across the top of the gas hydrate stability zone; in the second one, in-situ production of biogenic methane is derived from organic material trapped within the slope sediments. These two models have different implications for slope stability. Indeed, the dissociation of gas hydrate has been proposed to be responsible for landslides on continental slopes. The availability of a dense grid of quality multichannel seismic profiles as well as multibeam bathymetric data across an area encompassing the Late Quaternary, 10,000 km2 Currituck landslide as well as the continental slope below the shelf-edge pockmarks provide the opportunity to test these two models. We analyzed the seismic data and produced a comprehensive map of the extent of the bottom-simulating reflector (BSR), the reversed-polarity reflector marking the base of gas hydrate, as well as of landslide deposits throughout the area. In addition, the systematic analysis of the multibeam bathymetry and CHIRP data provide an inventory of active methane seeps throughout the same area. Emerging relationships will test which of the gas hydrate

  16. Part C Updates: Fourth in a Series of Updates on Selected Aspects of the Early Intervention Program for Infants and Toddlers with Disabilities, Part C of the Individuals with Disabilities Education Act (IDEA).

    ERIC Educational Resources Information Center

    Danaher, Joan, Ed.

    Part C Updates is a compilation of information on various aspects of the Early Intervention Program for Infants and Toddlers with Disabilities (Part C) of the Individuals with Disabilities Education Act (IDEA). The intent of the compilation is to collect, in a convenient format, a variety of resources that meet the information needs of state and…

  17. Using Methane 14C to Determine the Origin of the Rapid Methane Rise at the End of the Younger Dryas 11,600 Years Ago: Increased Wetland Production or Methane Hydrates? A Progress Report.

    NASA Astrophysics Data System (ADS)

    Petrenko, V. V.; Severinghaus, J.; Brook, E.; Reeh, N.

    2002-12-01

    The atmospheric methane concentration rose from about 500 parts per billion (ppb) to about 750 ppb over a period of just 150 years at the termination of the Younger Dryas cold period 11,600 years ago, as indicated by Greenland ice core records. The start of this rapid methane increase was synchronous with an even more rapid climate warming -- Greenland ice core nitrogen and argon isotope records indicate that temperatures rose 5 - 10 ?C over just a few decades. There has been considerable debate about the source of this methane rise. Currently, the two main hypotheses attribute the methane rise either to increased bacterial methane production in wetlands, or to the dissociation of large quantities of methane hydrates on the ocean floor. Here we describe the progress of a project whose aim is to determine the origin of this methane rise. Our approach involves using 14C of ancient methane (derived from air bubbles in glacial ice) to determine its source. Methane hydrates are hundreds of thousands to millions of years old, and should contain virtually no 14C, whereas wetland-derived methane will have 14C content identical to that of atmospheric CO2 at the time of production. Obtaining enough ancient methane for a 14C measurement requires very large samples -- about 2 cubic meters. We have been able to locate a site on the western margin of the Greenland ice sheet where large amounts of uncontaminated ancient ice are available at the surface. Furthermore, our measurements of oxygen isotopes in the ice, as well as measurements of methane and oxygen and nitrogen isotopes in the air trapped in this ice have allowed us to date the ice and precisely locate the ice that contains the end-of-Younger-Dryas methane increase signal. Our data also demonstrate that the methane record in this ice is uncontaminated and suitable for methane 14C analysis. During the past year, we also constructed and are testing a device for melting and extracting air from large volumes of glacial ice.

  18. Exponential model describing methane production kinetics in batch anaerobic digestion: a tool for evaluation of biochemical methane potential assays.

    PubMed

    Brulé, Mathieu; Oechsner, Hans; Jungbluth, Thomas

    2014-09-01

    Biochemical methane potential assays, usually run in batch mode, are performed by numerous laboratories to characterize the anaerobic degradability of biogas substrates such as energy crops, agricultural residues, and organic wastes. Unfortunately, the data obtained from these assays lacks common, universal bases for comparison, because standard protocols did not diffuse to the entire scientific community. Results are usually provided as final values of the methane yields of substrates. However, methane production curves generated in these assays also provide useful information about substrate degradation kinetics, which is rarely exploited. A basic understanding of the kinetics of the biogas process may be a first step towards a convergence of the assay methodologies on an international level. Following this assumption, a modeling toolbox containing an exponential model adjusted with a simple data-fitting method has been developed. This model should allow (a) quality control of the assays according to the goodness of fit of the model onto data series generated from the digestion of standard substrates, (b) interpretation of substrate degradation kinetics, and (c) estimate of the ultimate methane yield at infinite time. The exponential model is based on two assumptions: (a) the biogas process is a two-step reaction yielding VFA as intermediate products, and methane as the final product, and (b) the digestible substrate can be divided into a rapidly degradable and a slowly degradable fraction.

  19. Erbeta Ligands. Part 5: Synthesis and Structure-Activity Relationships of a Series of 4'-hydroxyphenyl-aryl-carbaldehyde Oxime Derivatives

    SciTech Connect

    Mewshaw,R.; Bowen, S.; Harris, H.; Xu, Z.; Manas, E.; Cohn, S.

    2007-01-01

    A series of 4'-hydroxyphenyl-aryl-carbaldehyde oximes (5b) was prepared and found to have high affinity (4 nM) and modest selectivity (39-fold) for estrogen receptor-{beta} (ER{beta}). Substitution of one of the core rings of the scaffold based around these novel ligands further expanded our knowledge in the quest toward achieving high affinity and selectivity for ER{beta}. An X-ray co-crystal of structure 11 revealed that the oxime moiety was mimicking the C-ring of genistein, as previously predicted by SAR and docking studies.

  20. IUPAC-NIST Solubility Data Series. 98. Solubility of Polycyclic Aromatic Hydrocarbons in Pure and Organic Solvent Mixtures--Revised and Updated. Part 3. Neat Organic Solvents

    NASA Astrophysics Data System (ADS)

    Acree, William E.

    2013-03-01

    This work updates Vols. 54, 58, and 59 in the IUPAC Solubility Data Series and presents solubility data for polycyclic aromatic hydrocarbon solutes dissolved in neat organic solvents. Published solubility data for acenaphthene, anthracene, biphenyl, carbazole, dibenzofuran, dibenzothiophene, fluoranthene, fluorene, naphthalene, phenanthrene, phenothiazine, pyrene, thianthrene, and xanthene that appeared in the primary literature from 1995 to the end of 2011 are compiled and critically evaluated. Experimental solubility data for more than 550 different solute-organic solvent systems are included. Solubility data published prior to 1995 were contained in three earlier volumes (Vols. 54, 58, and 59) and are not repeated in this volume.

  1. IUPAC-NIST Solubility Data Series. 98. Solubility of Polycyclic Aromatic Hydrocarbons in Pure and Organic Solvent Mixtures: Revised and Updated. Part 1. Binary Solvent Mixtures

    NASA Astrophysics Data System (ADS)

    Acree, William E.

    2013-03-01

    This work updates Vols. 54, 58, and 59 in the IUPAC Solubility Data Series and presents solubility data for polycyclic aromatic hydrocarbon solutes dissolved in binary organic solvent mixtures. Published solubility data for anthracene, naphthalene, phenanthrene, phenothiazine, and pyrene that appeared in the primary literature between 1995 to the end of 2011 are compiled and critically evaluated. Experimental solubility data for 360 different solute-binary solvent systems are included in the volume. Solubility data published prior to 1995 were contained in three earlier volumes (Vols. 54, 58, and 59) and are not repeated in this volume.

  2. IUPAC-NIST Solubility Data Series. 98. Solubility of Polycyclic Aromatic Hydrocarbons in Pure and Organic Solvent Mixtures: Revised and Updated. Part 2. Ternary Solvent Mixtures

    NASA Astrophysics Data System (ADS)

    Acree, William E.

    2013-03-01

    This work updates Vols. 54, 58, and 59 in the IUPAC Solubility Data Series and presents solubility data for polycyclic aromatic hydrocarbon solutes dissolved in ternary organic solvent mixtures. Published solubility data for anthracene, phenanthrene, and pyrene that appeared in the primary literature between 1995 to the end of 2011 are compiled and critically evaluated. Experimental solubility data for 119 different solute-ternary solvent systems are included in the volume. Solubility data published prior to 1995 were contained in three earlier volumes (Vols. 54, 58, and 59) and are not repeated here.

  3. Archaebacterial Fuel Production: Methane from Biomass.

    ERIC Educational Resources Information Center

    Lennox, John E.; And Others

    1983-01-01

    Discusses microbial production of methane from biomass. Topics include methogens (bacteria producing methane), ecology of methanogenesis, methanogenesis in ruminant/nonruminant and other environments, role of methanogenesis in nature, and methane production in sewage treatment plants. Also discusses construction of methane digesters (and related…

  4. Archaebacterial Fuel Production: Methane from Biomass.

    ERIC Educational Resources Information Center

    Lennox, John E.; And Others

    1983-01-01

    Discusses microbial production of methane from biomass. Topics include methogens (bacteria producing methane), ecology of methanogenesis, methanogenesis in ruminant/nonruminant and other environments, role of methanogenesis in nature, and methane production in sewage treatment plants. Also discusses construction of methane digesters (and related…

  5. Oceanic Methane Concentrations in Three Mexican Regions

    EPA Science Inventory

    The atmospheric concentration of methane has increased significantly over the last several decades. Methane is an important greenhouse gas, and it is important to better quantify methane sources and sinks. Dissolved methane in the ocean is produced by biological and hydrothermal ...

  6. 75 FR 9886 - Methane Hydrate Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-04

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Methane... meeting. SUMMARY: This notice announces a meeting of the Methane Hydrate Advisory Committee. Federal... Methane Hydrate Advisory Committee is to provide advice on potential applications of methane hydrate...

  7. Oceanic Methane Concentrations in Three Mexican Regions

    EPA Science Inventory

    The atmospheric concentration of methane has increased significantly over the last several decades. Methane is an important greenhouse gas, and it is important to better quantify methane sources and sinks. Dissolved methane in the ocean is produced by biological and hydrothermal ...

  8. Quantification of methane fluxes from industrial sites using a combination of a tracer release method and a Gaussian model

    NASA Astrophysics Data System (ADS)

    Ars, S.; Broquet, G.; Yver-Kwok, C.; Wu, L.; Bousquet, P.; Roustan, Y.

    2015-12-01

    Greenhouse gas (GHG) concentrations keep on increasing in the atmosphere since industrial revolution. Methane (CH4) is the second most important anthropogenic GHG after carbon dioxide (CO2). Its sources and sinks are nowadays well identified however their relative contributions remain uncertain. The industries and the waste treatment emit an important part of the anthropogenic methane that is difficult to quantify because the sources are fugitive and discontinuous. A better estimation of methane emissions could help industries to adapt their mitigation's politic and encourage them to install methane recovery systems in order to reduce their emissions while saving money. Different methods exist to quantify methane emissions. Among them is the tracer release method consisting in releasing a tracer gas near the methane source at a well-known rate and measuring both their concentrations in the emission plume. The methane rate is calculated using the ratio of methane and tracer concentrations and the emission rate of the tracer. A good estimation of the methane emissions requires a good differentiation between the methane actually emitted by the site and the methane from the background concentration level, but also a good knowledge of the sources distribution over the site. For this purpose, a Gaussian plume model is used in addition to the tracer release method to assess the emission rates calculated. In a first step, the data obtained for the tracer during a field campaign are used to tune the model. Different model's parameterizations have been tested to find the best representation of the atmospheric dispersion conditions. Once these parameters are set, methane emissions are estimated thanks to the methane concentrations measured and a Bayesian inversion. This enables to adjust the position and the emission rate of the different methane sources of the site and remove the methane background concentration.

  9. Attention turns to naturally occurring methane seepage

    NASA Astrophysics Data System (ADS)

    Kvenvolden, Keith A.; Lorenson, Thomas D.; Reeburgh, William S.

    Methane is the most abundant organic compound in the Earth's atmosphere. As a powerful greenhouse gas, it has implications for global climate change. Sources of methane to the atmosphere are varied. Depending on the source, methane can contain either modern or ancient carbon. Methane exiting from swamps and wetlands contains modern carbon, whereas methane leaking from petroleum reservoirs contains ancient carbon. The total annual source of methane to the atmosphere has been constrained to about 540 teragrams (Tg) per year “Cicerone and Oremland, 1988”. Notably absent from any identified sources is the contribution of geologically sourced methane from naturally occurring seepage.

  10. IUPAC-NIST Solubility Data Series. 100. Rare Earth Metal Fluorides in Water and Aqueous Systems. Part 2. Light Lanthanides (Ce-Eu)

    NASA Astrophysics Data System (ADS)

    Mioduski, Tomasz; Gumiński, Cezary; Zeng, Dewen

    2015-03-01

    This is the second part of the volume devoted to the evaluation of experimental solubility data for rare earth metal (REM) fluorides in water as well as in aqueous ternary and multicomponent systems. Fluorides of Ce, Pr, Nd, Pm, Sm, and Eu (so-called light lanthanides), as the main solutes, are covered in the present part, which has thorough coverage of the experimental literature through the end of 2012. The experimentally unknown solubility value for PmF3 in water was predicted by an interpolation of the solubility values for NdF3 and SmF3 at 298 K. General features of the systems, such as the nature of the equilibrium solid phases, solubility as a function of temperature, influence of ionic strength, pH, mixed solvent medium on the solubility, quality of the solubility results, and solubility as a function of REM atomic number, have already been presented in Part 1 of the volume.

  11. Forecasting peak daily ozone levels: part 2--A regression with time series errors model having a principal component trigger to forecast 1999 and 2002 ozone levels.

    PubMed

    Liu, Pao-Wen Grace; Johnson, Richard

    2003-12-01

    A modified time series approach, a Box-Jenkins regression with time series errors (RTSE) model plus a principal component (PC) trigger, has been developed to forecast peak daily 1-hr ozone (O3) in real time at the University of Wisconsin-Milwaukee North (UWM-N) during 1999 and 2002. The PC trigger acts as a predictor variable in the RTSE model. It tries to answer the question: will the next day be a possible high O3 day? To answer this question, three PC trigger rules were developed: (1) Hi-Low Checklist, (2) Discriminant Function Approach I, and (3) Discriminant Function Approach II. Also, a pure RTSE model without including the PC trigger and a persistence approach were tested for comparison. The RTSE model with DFA I successfully forecast the only two 1-hr federal exceedances (124 ppb), one in 1999 and one in 2002. In terms of the O3 100-ppb exceedances, 60-80% of the incorrect forecasts occurred with incorrect PC decisions. A few others may have been caused by unexpected O3-weather relations. When the three approaches used UWM-N data to forecast a 100-ppb exceedance somewhere in the Milwaukee, WI, metropolitan area, their performance was dramatically improved: the false alarm rate was reduced from 0.89 to 0.44, and the probability of detection was increased from 0.71 to 0.88.

  12. Effects of Monovalent Anions of the Hofmeister Series on DPPC Lipid Bilayers Part I: Swelling and In-Plane Equations of State

    PubMed Central

    Aroti, A.; Leontidis, E.; Dubois, M.; Zemb, T.

    2007-01-01

    Aiming to improve understanding of the mechanisms behind specific anion effects in biological systems we have studied the effects of sodium salts of simple monovalent anions belonging to the Hofmeister series on the bilayers of the zwitterionic lipid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine using small-angle x-ray scattering and the osmotic stress technique. NaCl, NaBr, NaNO3, NaI, and NaSCN were used in this investigation. The electrolytes were found to swell the bilayers and to increase the area per lipid headgroup at each value of the osmotic pressure, suggesting the association of anions with the bilayer-lipid interfaces. The effects follow the Hofmeister series with SCN− inducing the most pronounced changes. “Ion competition” experiments with mixed NaI/NaCl solutions at total salinity 0.1 and 0.5 M revealed that the effect of ions on the lipid equation-of-state is roughly linear at low concentrations, but strongly nonlinear at high concentrations. The experimental results are fitted in a companion article to provide “binding” or “partitioning” constants of anions in the lipid bilayers. PMID:17496051

  13. Anthropogenic methane ebullition and continuous flux measurement

    NASA Astrophysics Data System (ADS)

    Alshboul, Zeyad

    2017-04-01

    Keywords: Methane, Wastewater, Effluent, Anaerobic treatment. Municipal wastewater treatment plants (WWTPs) have shown to emit significant amount of methane during treatment processes. While most of studies cover only in-plant diffusive methane flux, magnitude and sources of methane ebullition have not well assessed. Moreover, the reported results of methane emissions from WWTPs are based on low spatial and temporal resolution. Using a continuous measurement approach of methane flux rate for effluent system and secondary clarifier treatment process at one WWTP in Southwest Germany, our results show that high percentage of methane is emitted by ebullition during the anaerobic treatment (clarification pond) with high spatial and temporal variability. Our measurements revealed that no ebullition is occur at the effluent system. The observed high contribution of methane ebullition to the total in-plant methane emission, emphasizes the need for considering in-plant methane emission by ebullition as well as the spatial and temporal variability of these emissions.

  14. Methane emissions from oceans, coasts, and freshwater habitats: New perspectives and feedbacks on climate

    USGS Publications Warehouse

    Hamdan, Leila J.; Wickland, Kimberly P.

    2016-01-01

    Methane is a powerful greenhouse gas, and atmospheric concentrations have risen 2.5 times since the beginning of the Industrial age. While much of this increase is attributed to anthropogenic sources, natural sources, which contribute between 35% and 50% of global methane emissions, are thought to have a role in the atmospheric methane increase, in part due to human influences. Methane emissions from many natural sources are sensitive to climate, and positive feedbacks from climate change and cultural eutrophication may promote increased emissions to the atmosphere. These natural sources include aquatic environments such as wetlands, freshwater lakes, streams and rivers, and estuarine, coastal, and marine systems. Furthermore, there are significant marine sediment stores of methane in the form of clathrates that are vulnerable to mobilization and release to the atmosphere from climate feedbacks, and subsurface thermogenic gas which in exceptional cases may be released following accidents and disasters (North Sea blowout and Deepwater Horizon Spill respectively). Understanding of natural sources, key processes, and controls on emission is continually evolving as new measurement and modeling capabilities develop, and different sources and processes are revealed. This special issue of Limnology and Oceanography gathers together diverse studies on methane production, consumption, and emissions from freshwater, estuarine, and marine systems, and provides a broad view of the current science on methane dynamics of aquatic ecosystems. Here, we provide a general overview of aquatic methane sources, their contribution to the global methane budget, and key uncertainties. We then briefly summarize the contributions to and highlights of this special issue.

  15. Diversity of Methane related archaea in shallow marine sediment of eastern margin of Japan Sea

    NASA Astrophysics Data System (ADS)

    Imajo, T.

    2016-12-01

    In the eastern margin of Japan Sea, the shallow methane hydrates are said to be buried in wide area, and their geochemical features of methane which is in the hydrates differs by each sea area. Also community structure analyses and isolation of methane related archaea were performed using shallower sediments, but the research on the sediments which methane hydrates forms or exists are yet not to be done. Therefore this study focuses on community structure analyses on methane related archaea at the depth of which methane hydrates exists. Shallow marine sediments were collected from drilling project held in 2014 and 2015 at the several site of eastern margin of Japan Sea. We extracted target DNA directly from the sediments and amplified the PCR method using methane related archaea specific primers. After that we used clone library methods to investigate the community structure analyses. The results were subseafloor of each area has no difference in the community, but the shallower sediment below those had different community structure. We also found out that those included the order which is expected to be the new order of methanogen, so we expect more methane production than what we had expected. This study was conducted under the commission from AIST as a part of the methane hydrate research project funded by METI (the Ministry of Economy, Trade and Industry, Japan).

  16. Methane microprofiles in a sewage biofilm determined with a microscale biosensor.

    PubMed

    Damgaard, L R; Nielsen, L P; Revsbech, N P

    2001-04-01

    Microprofiles of the methane concentration in a 3.5-mm-thick sewage outlet biofilm were measured at high spatial and temporal resolution using a microscale biosensor for methane. In the freshly collected biofilm, methane was building up to a concentration of 175 mumol l-1 at 3 mm depth with a total methanogenesis of 0.14 mumol m-2 s-1, as compared to an aerobic respiration (including methane oxidation) of 0.80 mumol m-2 s-1. A model biofilm was established by homogenisation of an in situ biofilm and 12 days of incubation with surplus sodium acetate. The homogenised biofilm was able to maintain 50% of the methanogenic activity in the absence of external electron donor. Oxygen had only a minor effect on the methane production, but aerobic respiration consumed a substantial part of the produced methane and was thus an important control on methane export from the biofilm. A concentration of 2 mmol l-1 nitrate was shown to inhibit methanogenesis only in the upper layer of the biofilm, whereas a further addition of 2 mmol l-1 sulphate inhibited methanogenesis in the entire biofilm. The study demonstrated the power of the methane microsensor in the study of microhabitats with concurrent production and consumption of methane.

  17. Water Column Methanotrophy Fueled by Methane from the Hudson Canyon Seep Field, US Atlantic Margin

    NASA Astrophysics Data System (ADS)

    Redmond, M. C.; Chan, E. W.; Kellermann, M. Y.; Arrington, E.; Valentine, D. L.; Kessler, J. D.

    2014-12-01

    Several areas of methane seepage have recently been discovered along the US Atlantic margin, including parts of Hudson Canyon, offshore New York and New Jersey. However, little is known about the magnitude of seepage, the fate of this methane once it enters the water column, or the bacteria that may consume it. In July 2014, water column methane concentrations were measured throughout Hudson Canyon and methane oxidation tracked using a 13C-methane tracer. Samples for microbial community composition analysis were collected throughout the water column in areas with and without active seepage. 16S rRNA gene sequencing will be used to compare microbial communities from different depths, locations, and in samples with low and high methane concentrations and oxidation rates. DNA stable isotope probing experiments with 13C-labeled methane were also conducted and will be used to detect active water column methanotrophs from seep and non-seep sites. In addition, mesocosm experiments were used for high resolution measurements of methane oxidation, with samples for microbial community composition taken at several time points. 16S rRNA gene sequencing will be used to track changes in methanotrophic bacteria and the overall microbial community as methane was consumed.

  18. Geologic methane seeps along boundaries of Arctic permafrost thaw and melting glaciers

    NASA Astrophysics Data System (ADS)

    Walter Anthony, Katey M.; Anthony, Peter; Grosse, Guido; Chanton, Jeffrey

    2012-06-01

    Methane, a potent greenhouse gas, accumulates in subsurface hydrocarbon reservoirs, such as coal beds and natural gas deposits. In the Arctic, permafrost and glaciers form a `cryosphere cap' that traps gas leaking from these reservoirs, restricting flow to the atmosphere. With a carbon store of over 1,200Pg, the Arctic geologic methane reservoir is large when compared with the global atmospheric methane pool of around 5Pg. As such, the Earth's climate is sensitive to the escape of even a small fraction of this methane. Here, we document the release of 14C-depleted methane to the atmosphere from abundant gas seeps concentrated along boundaries of permafrost thaw and receding glaciers in Alaska and Greenland, using aerial and ground surface survey data and in situ measurements of methane isotopes and flux. We mapped over 150,000 seeps, which we identified as bubble-induced open holes in lake ice. These seeps were characterized by anomalously high methane fluxes, and in Alaska by ancient radiocarbon ages and stable isotope values that matched those of coal bed and thermogenic methane accumulations. Younger seeps in Greenland were associated with zones of ice-sheet retreat since the Little Ice Age. Our findings imply that in a warming climate, disintegration of permafrost, glaciers and parts of the polar ice sheets could facilitate the transient expulsion of 14C-depleted methane trapped by the cryosphere cap.

  19. Improving dust and methane control

    SciTech Connect

    Cecala, A.B.; Organiscak, A.; Jankowski, R.A.

    1987-01-01

    This paper evaluates a number of techniques for controlling dust and methane during the headgate cutout of retreating longwall sections that use antitropal ventilation (headgate to tailgate). Some of these techniques are effective for both methane and dust control, while others are effective for only one or the other. The techniques include the gob curtain, the walkway curtain, stageloader-crusher control, and the wing curtain. Each improves the health and safety of workers and is economically feasible in hardware cost, setup cost, and maintenance. By combining various of these techniques, mine operators can substantially reduce the dust and methane concentrations at the shearer and ensure the health and safety of longwall workers.

  20. Phase behavior of methane haze.

    PubMed

    Signorell, R; Jetzki, M

    2007-01-05

    Methane aerosols play a fundamental role in the atmospheres of Neptune, Uranus, and Saturn's moon Titan as borne out by the recent Cassini-Huygens mission. Here we present the first study of the phase behavior of free methane aerosol particles combining collisional cooling with rapid-scan infrared spectroscopy in situ. We find fast (within minutes) phase transitions to crystalline states directly after particle formation and characteristic surface effects for nanometer-sized particles. From our results, we conclude that in atmospheric clouds solid methane particles are crystalline.

  1. Methane hydroxylation: a biomimetic approach

    NASA Astrophysics Data System (ADS)

    Shilov, Aleksandr E.; Shteinman, Al'bert A.

    2012-04-01

    The review addresses direct methane oxidation — an important fundamental problem, which has attracted much attention of researchers in recent years. Analysis of the available results on biomimetic and bio-inspired methane oxygenation has demonstrated that assimilating of the experience of Nature on oxidation of methane and other alkanes significantly enriches the arsenal of chemistry and can radically change the character of the entire chemical production, as well as enables the solution of many material, energetic and environmental problems. The bibliography includes 310 references.

  2. Methane gas from cannery wastes

    SciTech Connect

    Not Available

    1981-12-01

    It is estimated that California produces 500,000 tons of tomato waste and 105,000 tons of peach waste from canneries every year. Results from a two-year investigation, including laboratory studies and pilot-plant operations indicate that it is possible to create methane gas through the anaerobic digestion of these cannery wastes. This article describes studies to determine the methane - generating potential of tomato and peach cannery wastes and of honeydew-melon culls separated in the field. A mobile pilot-scale methane plant situated at the T.H. Richards food processing plant in Sacramento is described.

  3. (Methane digester). Final report

    SciTech Connect

    Waybright, R.C.

    1981-01-01

    The purpose of the grant was to construct and operate a methane digester for dairy manure involving the latest state-of-the-art technics. The first step taken was to empty out the existing digester to evaluate its performance and to gain ideas of how to build the next digester so it would operate more efficiently. Next, the design criteria was set up in order to eliminate some problems involved with the first digester and also new ideas as to how to build the next one without a protective building and testing simplified construction technics. After this the digester construction was started with the completion date in late January. The digester was then filled and operated at different temperatures attempting to achieve the optimum operating range.

  4. Tetraperchlorate of methane

    NASA Technical Reports Server (NTRS)

    Schack, C. J.

    1972-01-01

    The preparation of the tetraperchlorate of methane (TPM) was attempted. Displacement of halogen from carbon tetrahalides was accomplished with either CCl4 or CBr4 using the halogen perchlorates, ClOClO3, and BOClO3. Although the displacement process was successful, the generated carbon perchlorate intermediates were not isolated. Instead, these species decomposed to COCl2, CO2, and Cl2O7. The vigorous displacement reaction that often occurred required moderation. Fluorocarbon solvents and chlorine perchlorate were successfully tested for compatibility, permitting their use in these synthetic reactions. While the sought for moderating effect was obtained, the net result of the displacement of halogen from CX sub 4 substrates was the same as before. Thus only CO2, COCl2, and Cl2O7 were isolated.

  5. Methane: A Menace Surfaces

    NASA Astrophysics Data System (ADS)

    Anthony, Katey Walter

    2011-11-01

    The arctic permafrost is thawing, releasing organic matter that was frozen in the ground into the bottoms of lakes. This organic matter feeds microbes that produce methane, which in turn escapes to the atmosphere. Permafrost, a rich source of organic carbon, covers 20% of the earth's land surface, and one third to one half of permafrost is now within 1.0 ° C to 3 ° C of thawing. New estimates indicate that by 2100, thawing permafrost could boost emissions of methane—a greenhouse gas that's 25 times more potent than carbon dioxide—by 20 to 40 percent beyond what would be produced by all natural and man-made sources. As a result, the earth's mean annual temperature could rise by an additional 0.32 ° C, further upsetting weather patterns and sea level.

  6. Potential impact of salinity on methane production from food waste anaerobic digestion.

    PubMed

    Zhao, Jianwei; Liu, Yiwen; Wang, Dongbo; Chen, Fei; Li, Xiaoming; Zeng, Guangming; Yang, Qi

    2017-09-01

    Previous studies have demonstrated that the presence of sodium chloride (NaCl) inhibited the production of methane from food waste anaerobic digestion. However, the details of how NaCl affects methane production from food waste remain unknown by now and the efficient approach to mitigate the impact of NaCl on methane production was seldom reported. In this paper, the details of how NaCl affects methane production was first investigated via a series of batch experiments. Experimental results showed the effect of NaCl on methane production was dosage dependent. Low level of NaCl improved the hydrolysis and acidification but inhibited the process of methanogenesis whereas high level of NaCl inhibit both steps of acidification and methanogenesis. Then an efficient approach, i.e. co-digestion of food waste and waste activated sludge, to mitigate the impact of NaCl on methane production was reported. Finally, the mechanisms of how co-digestion mitigates the effect on methane production caused by NaCl in co-digestion system were revealed. These findings obtained in this work might be of great importance for the operation of methane recovery from food waste in the presence of NaCl. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Gas hydrate formation rates from dissolved-phase methane in porous laboratory specimens

    USGS Publications Warehouse

    Waite, William F.; Spangenberg, E.K.

    2013-01-01

    Marine sands highly saturated with gas hydrates are potential energy resources, likely forming from methane dissolved in pore water. Laboratory fabrication of gas hydrate-bearing sands formed from dissolved-phase methane usually requires 1–2 months to attain the high hydrate saturations characteristic of naturally occurring energy resource targets. A series of gas hydrate formation tests, in which methane-supersaturated water circulates through 100, 240, and 200,000 cm3 vessels containing glass beads or unconsolidated sand, show that the rate-limiting step is dissolving gaseous-phase methane into the circulating water to form methane-supersaturated fluid. This implies that laboratory and natural hydrate formation rates are primarily limited by methane availability. Developing effective techniques for dissolving gaseous methane into water will increase formation rates above our observed (1 ± 0.5) × 10−7 mol of methane consumed for hydrate formation per minute per cubic centimeter of pore space, which corresponds to a hydrate saturation increase of 2 ± 1% per day, regardless of specimen size.

  8. From Animal Waste to Energy; A Study of Methane Gas converted to Energy.

    NASA Astrophysics Data System (ADS)

    Weiss, S.

    2016-12-01

    Does animal waste produce enough harvestable energy to power a household, and if so, what animal's waste can produce the most methane that is usable. What can we power using this methane and how can we power these appliances within an average household using the produced methane from animal waste. The waste product from animals is readily available all over the world, including third world countries. Using animal waste to produce green energy would allow low cost energy sources and give independence from fossil fuels. But which animal produces the most methane and how hard is it to harvest? Before starting this experiment I knew that some cow farms in the northern part of the Central California basin were using some of the methane from the waste to power their machinery as a safer, cheaper and greener source through the harnessed methane gas in a digester. The fermentation process would occur in the digester producing methane gasses as a side product. Methane that is collected can later be burned for energy. I have done a lot of research on this experiment and found that many different farm and ranch animals produce methane, but it was unclear which produced the most. I decided to focus my study on the waste from cows, horses, pig and dogs to try to find the most efficient and strongest source of methane from animal waste. I produced an affordable methane digester from plastic containers with a valve to attach a hose. By putting in the waste product and letting it ferment with water, I was able to produce and capture methane, then measure the amount with a Gaslab meter. By showing that it is possible to create energy with this simple digester, it could reduce pollution and make green energy easily available to communities all over the world. Eventually this could result into our sewer systems converting waste to energy, producing an energy source right in your home.

  9. Microbial and Isotopic Evidence for Methane Cycling in Hydrocarbon-Containing Groundwater from the Pennsylvania Region

    PubMed Central

    Vigneron, Adrien; Bishop, Andrew; Alsop, Eric B.; Hull, Kellie; Rhodes, Ileana; Hendricks, Robert; Head, Ian M.; Tsesmetzis, Nicolas

    2017-01-01

    The Pennsylvania region hosts numerous oil and gas reservoirs and the presence of hydrocarbons in groundwater has been locally observed. However, these methane-containing freshwater ecosystems remain poorly explored despite their potential importance in the carbon cycle. Methane isotope analysis and analysis of low molecular weight hydrocarbon gases from 18 water wells indicated that active methane cycling may be occurring in methane-containing groundwater from the Pennsylvania region. Consistent with this observation, multigenic qPCR and gene sequencing (16S rRNA genes, mcrA, and pmoA genes) indicated abundant populations of methanogens, ANME-2d (average of 1.54 × 104 mcrA gene per milliliter of water) and bacteria associated with methane oxidation (NC10, aerobic methanotrophs, methylotrophs; average of 2.52 × 103 pmoA gene per milliliter of water). Methane cycling therefore likely represents an important process in these hydrocarbon-containing aquifers. The microbial taxa and functional genes identified and geochemical data suggested that (i) methane present is at least in part due to methanogens identified in situ; (ii) Potential for aerobic and anaerobic methane oxidation is important in groundwater with the presence of lineages associated with both anaerobic an aerobic methanotrophy; (iii) the dominant methane oxidation process (aerobic or anaerobic) can vary according to prevailing conditions (oxic or anoxic) in the aquifers; (iv) the methane cycle is closely associated with the nitrogen cycle in groundwater methane seeps with methane and/or methanol oxidation coupled to denitrification or nitrate and nitrite reduction. PMID:28424678

  10. Attributes and National Behavior, Part 2: Modern International Relations Monograph Series. Relative Status-Field Theory, Results for Cooperation, UT Actors, 1966-1969, An Inventory of Findings.

    ERIC Educational Resources Information Center

    Vincent, Jack E.

    This monograph is a computer printout which presents findings from an analysis of data on international cooperation over a three-year period. Part of a large scale research project to test various theories with regard to their ability to analyze international relations, this monograph presents the computer printout of data on the application of…

  11. Attributes and National Behavior, Part 2: Modern International Relations Monograph Series. Social Field Theory, Results for Conflict, 1966-69, An Inventory of Findings.

    ERIC Educational Resources Information Center

    Vincent, Jack E.

    Part of a large scale research project to test various theories with regard to their ability to analyze international relations, this computer printout presents data on the application of social field theory to patterns of conflict among nations. Social field theory implies that international relations is a field which consists of all the…

  12. Financial Analysis and Mathematics of Business: Part IV in a Series--Preparation for Certified Professional Secretary Examination. An Instructor's Guide for an Adult Course.

    ERIC Educational Resources Information Center

    Gonyea, Adrian C.

    The instructor's guide provides a review for those preparing to take Part IV of the Certified Professional Secretary (CPS) examination. Course content can also help secretaries update their skills in accounting and business mathematics. Organized into lessons with objectives, content outline, and teaching suggestions and references, the units…

  13. Attributes and National Behavior, Part 2: Modern International Relations Monograph Series. Relative Status-Field Theory, Results for Conflict, UT Behavior, 1966-69.

    ERIC Educational Resources Information Center

    Vincent, Jack E.

    This monograph presents findings from an analysis of data on international conflict over a three-year period. Computer printout of the analysis is included. Part of a large scale research project to test various theories with regard to their ability to analyze international relations, this monograph reports on the testing of relative status field…

  14. Attributes and National Behavior, Part 2: Modern International Relations Monograph Series. Relative Status-Field Theory, Results for Cooperation, TU Actors, 1966-1969, An Inventory of Findings.

    ERIC Educational Resources Information Center

    Vincent, Jack E.

    This monograph is a computer printout which presents findings from an analysis of data on international cooperation over a three-year period. The document is part of a large scale research project to test various theories with regard to their ability to analyze international relations. In this monograph, data are analyzed according to relative…

  15. Attributes and National Behavior, Part 2: Modern International Relations Monograph Series. Relative Status-Field Theory, Results for Conflict, UT Actors, 1966-1969, An Inventory of Findings.

    ERIC Educational Resources Information Center

    Vincent, Jack E.

    This monograph is a computer printout which presents findings from an analysis of data on international conflict over a three-year period. Part of a large scale research project to test various theories with regard to their ability to analyze international relations, this monograph presents the computer printout of data on the application of…

  16. Attributes and National Behavior, Part 2: Modern International Relations Monograph Series. Relative Status-Field Theory, Results for Conflict, TT Actors, 1966-69, An Inventory of Findings.

    ERIC Educational Resources Information Center

    Vincent, Jack E.

    This monograph presents findings on international conflict over a three-year period. Part of a large scale research project to test various theories with regard to their power in analyzing international relations, this monograph presents a computer printout of data regarding 'topdog' behavior among nations with regard to economic development and…

  17. Attributes and National Behavior, Part 2: Modern International Relations Monograph Series. Patterns of Cooperation: Relative Status-Field Theory, TT Actors.

    ERIC Educational Resources Information Center

    Vincent, Jack E.

    This monograph presents findings from an analysis of data on international cooperation over a three-year period. Part of a large scale research project to test various theories with regard to their power in analyzing international relations, this monograph reports on the testing of relative status field theory on WEIS conflict data for 1966-1969…

  18. Attributes and National Behavior, Part 2: Modern International Relations Monograph Series. Relative Status-Field Theory, Results for Cooperation, TU Behavior, 1966-69.

    ERIC Educational Resources Information Center

    Vincent, Jack E.

    This monograph presents findings from an analysis of data on international cooperation over a three-year period. Part of a large scale research project to test various theories with regard to their ability to analyze international relations, this monograph reports on the testing of relative status field theory on WEIS conflict data for 1966-1969…

  19. Attributes and National Behavior, Part 2: Modern International Relations Monograph Series. Relative Status-Field Theory, Results for Conflict, TU Actors, 1966-1969, An Inventory of Findings.

    ERIC Educational Resources Information Center

    Vincent, Jack E.

    This monograph presents findings from an analysis of data on international conflict over a three-year period. Part of a large scale research project to test various theories with regard to their power in analyzing international relations, this monograph presents the computer printout of data on the application of discriminant function analysis of…

  20. Attributes and National Behavior, Part 2: Modern International Relations Monograph Series. Patterns of Cooperation: Relative Status-Field Theory, TU Actors.

    ERIC Educational Resources Information Center

    Vincent, Jack E.

    This monograph presents the computer printout of an analysis of data on international cooperation over a three-year period. Part of a large scale research project to test various theories with regard to their power in analyzing international relations, this monograph presents data on the application of discriminant function analysis to combined…

  1. Attributes and National Behavior, Part 2: Modern International Relations Monograph Series. Relative Status-Field Theory, Results for Cooperation, TT Behavior, 1966-69.

    ERIC Educational Resources Information Center

    Vincent, Jack E.

    This monograph presents findings from an analysis of data on international cooperation over a three-year period. Part of a large scale research project to test various theories with regard to their ability to analyze international relations, this monograph reports on the testing of relative status field theory on WEIS conflict data for 1966-1969…

  2. Business and Public Policy; Instructor's Guide for an Adult Course. Part II in a Series of Preparation for Certified Professional Secretary Examination.

    ERIC Educational Resources Information Center

    Batten, Marion N.; Wakin, Bertha

    One of six courses to cover the six parts of the Certified Professional Secretary Examination, this course in business and public policy is appropriate for use in adult education programs, secondary schools, and community colleges of New York State. It is recommended that specific cases be used with each of the ten lessons to exemplify the major…

  3. Attributes and National Behavior, Part 2: Modern International Relations Monograph Series. Patterns of Cooperation: Relative Status-Field Theory, TU Actors.

    ERIC Educational Resources Information Center

    Vincent, Jack E.

    This monograph presents the computer printout of an analysis of data on international cooperation over a three-year period. Part of a large scale research project to test various theories with regard to their power in analyzing international relations, this monograph presents data on the application of discriminant function analysis to combined…

  4. Attributes and National Behavior, Part 2: Modern International Relations Monograph Series. Patterns of Conflict: Relative Status-Field Theory, TU Actors.

    ERIC Educational Resources Information Center

    Vincent, Jack E.

    This monograph presents the computer printout of an analysis of data on international conflict over a three-year period. Part of a large scale research project to test various theories with regard to their power in analyzing international relations, this monograph presents data on the application of discriminant function analysis to combined…

  5. Attributes and National Behavior, Part 2: Modern International Relations Monograph Series. Patterns of Conflict: Relative Status-Field Theory, TT Actors.

    ERIC Educational Resources Information Center

    Vincent, Jack E.

    This monograph presents the computer printout of an analysis of data on international conflict over a three-year period. Part of a large scale research project to test various theories with regard to their power in analyzing international relations, this monograph presents data on the application of discriminant function analysis to 'topdog'…

  6. Attributes and National Behavior, Part 2: Modern International Relations Monograph Series. Patterns of Cooperation: Relative Status-Field Theory, UU Actors.

    ERIC Educational Resources Information Center

    Vincent, Jack E.

    This monograph presents an analysis of data on international cooperation over a three-year period. Part of a large scale research project to test various theories with regard to their power in analyzing international relations, this monograph presents the computer printout of data on the application of second stage factor analysis of 'underdog'…

  7. Attributes and National Behavior, Part 2: Modern International Relations Monograph Series. Relative Status-Field Theory, Results for Conflict, UU Behavior, 1966-69.

    ERIC Educational Resources Information Center

    Vincent, Jack E.

    This monograph presents findings from an analysis of data on international conflict over a three-year period. Computer printout of the analysis is included. Part of a large scale research project to test various theories with regard to their ability to analyze international relations, this monograph reports on the testing of relative status field…

  8. Attributes and National Behavior, Part 2: Modern International Relations Monograph Series. Relative Status-Field Theory, Results for Cooperation, UU Behavior, 1966-69.

    ERIC Educational Resources Information Center

    Vincent, Jack E.

    This monograph presents findings from an analysis of data on international cooperation over a three-year period. Part of a large scale research project to test various theories with regard to their ability to analyze international relations, this monograph reports on the testing of relative status field theory on WEIS conflict data for 1966-1969…

  9. Attributes and National Behavior, Part 2: Modern International Relations Monograph Series. Relative Status-Field Theory, Results for Cooperation, UU Actors, 1966-1969, An Inventory of Findings.

    ERIC Educational Resources Information Center

    Vincent, Jack E.

    This monograph presents findings from an analysis of data on international cooperation over a three-year period. Part of a large scale research project to test various theories with regard to their power in analyzing international relations, this monograph presents the computer printout of data on the application of discriminant function analysis…

  10. Attributes and National Behavior, Part 2: Modern International Relations Monograph Series. Relative Status-Field Theory, Results for Conflict, UU Actors, 1966-1969, An Inventory of Findings.

    ERIC Educational Resources Information Center

    Vincent, Jack E.

    This monograph is a computer printout which presents findings from an analysis of data on international conflict over a three-year period. Part of a large scale research project to test various theories with regard to their ability to analyze international relations, this monograph presents the computer printout of data on the application of…

  11. Attributes and National Behavior, Part 2: Modern International Relations Monograph Series. Patterns of Conflict: Relative Status-Field Theory, UU Actors.

    ERIC Educational Resources Information Center

    Vincent, Jack E.

    This monograph presents the computer printout of an analysis of data on international conflict over a three-year period. Part of a large scale research project to test various theories with regard to their power in analyzing international relations, this monograph presents data on the application of discriminant function analysis of 'underdog'…

  12. Quantifying methane flux from lake sediments using multibeam sonar

    NASA Astrophysics Data System (ADS)

    Scandella, B.; Urban, P.; Delwiche, K.; Greinert, J.; Hemond, H.; Ruppel, C. D.; Juanes, R.

    2013-12-01

    methane fluxes from shallow-water bodies. Time series showing how the uncalibrated, sonar-detected flux estimate (black) varies inversely with the hydrostatic pressure (meters of water, blue) at 5-minute resolution during April 2012. Overlain is the time series of scaled gas flux from a mechanistic numerical model forced by the same hydrostatic pressure signal (orange).

  13. Identifying sources of methane sampled in the Arctic using δ13C in CH4 and Lagrangian particle dispersion modelling.

    NASA Astrophysics Data System (ADS)

    Cain, Michelle; France, James; Pyle, John; Warwick, Nicola; Fisher, Rebecca; Lowry, Dave; Allen, Grant; O'Shea, Sebastian; Illingworth, Samuel; Jones, Ben; Gallagher, Martin; Welpott, Axel; Muller, Jennifer; Bauguitte, Stephane; George, Charles; Hayman, Garry; Manning, Alistair; Myhre, Catherine Lund; Lanoisellé, Mathias; Nisbet, Euan

    2016-04-01

    An airmass of enhanced methane was sampled during a research flight at ~600 m to ~2000 m altitude between the North coast of Norway and Svalbard on 21 July 2012. The largest source of methane in the summertime Arctic is wetland emissions. Did this enhancement in methane come from wetland emissions? The airmass was identified through continuous methane measurements using a Los Gatos fast greenhouse gas analyser on board the UK's BAe-146 Atmospheric Research Aircraft (ARA) as part of the MAMM (Methane in the Arctic: Measurements and Modelling) campaign. A Lagrangian particle dispersion model (the UK Met Office's NAME model) was run backwards to identify potential methane source regions. This was combined with a methane emission inventory to create "pseudo observations" to compare with the aircraft observations. This modelling was used to constrain the δ13C CH4 wetland source signature (where δ13C CH4 is the ratio of 13C to 12C in methane), resulting in a most likely signature of -73‰ (±4‰7‰). The NAME back trajectories suggest a methane source region of north-western Russian wetlands, and -73‰ is consistent with in situ measurements of wetland methane at similar latitudes in Scandinavia. This analysis has allowed us to study emissions from remote regions for which we do not have in situ observations, giving us an extra tool in the determination of the isotopic source variation of global methane emissions.

  14. Uninhibited methane biogeochemistry: A candid view of interactions among soil processes made possible by stable isotope and inert tracers

    NASA Astrophysics Data System (ADS)

    von Fischer, J. C.

    2006-12-01

    Methane emission emerges as a highly variable property of ecosystems because the proximate controlling processes, methane production, consumption and transport, appear to vary considerably in both space and time. But the extent and importance of any co-correlation among these processes remains unclear. The idea of co-correlation is supported by a simplified model of methane fluxes that we have developed and by the frequently-observed relationship between net ecosystem productivity and methane emission. Yet the dominant approach toward problems in methane biogeochemistry remains focused on measuring or modeling each process individually and then assembling them into an understanding of the whole. This approach has arisen, in part, from our historic inability to measure methane production, consumption and transport simultaneously. Instead, one or more processes have been inhibited or excluded from consideration, leading to an incomplete picture of soil methane biogeochemistry. To overcome this limitation, we have used additions of 13C- labeled methane to simultaneously measure methane production and consumption in wetland soils. When coupled with additions of inert hydrologic and gas tracers (e.g., Br- and SF6), we have measured methane production, consumption and soil-atmosphere transport under field conditions with minimal disturbance. Our results reveal strong co-correlations among the processes that can be useful for building simpler, mechanistically-based models of ecosystem methane emissions.

  15. Wind-Tunnel Tests on a Series of Wing Models Through a Large Angle of Attack Range. Part I : Force Tests

    NASA Technical Reports Server (NTRS)

    Knight, Montgomery; Wenzinger, Carl J

    1930-01-01

    This investigation covers force tests through a large range of angle of attack on a series of monoplane and biplane wing models. The tests were conducted in the atmospheric wind tunnel of the National Advisory Committee for Aeronautics. The models were arranged in such a manner as to make possible a determination of the effects of variations in tip shape, aspect ratio, flap setting, stagger, gap, decalage, sweep back, and airfoil profile. The arrangements represented most of the types of wing systems in use on modern airplanes. The effect of each variable is illustrated by means of groups of curves. In addition, there are included approximate autorotational characteristics in the form of calculated ranges of "rotary instability." a correction for blocking in this tunnel which applies to monoplanes at large angles of attack has been developed, and is given in an appendix. (author)

  16. Mars Methane Analogue Mission (M3): Near Subsurface Electromagnetic Techniques and Analysis

    NASA Astrophysics Data System (ADS)

    Boivin, A.; Samson, C.; Holladay, J. S.; Cloutis, E. A.; Ernst, R. E.

    2012-03-01

    As part of the Canadian Space Agency's Mars Methane Analogue Mission, a micro-rover mission, an Electromagnetic Induction Sounder (EMIS) was used with the goal of demonstrating its value as a potential science instrument onboard future rovers.

  17. Methane-related microbial processes and metabolic stratification in a terrestrial mud volcano, southwestern Taiwan

    NASA Astrophysics Data System (ADS)

    Cheng, T.; Lin, L.; Wang, P.; Chu, P.; Wu, J.

    2009-12-01

    Mud volcanoes are distinct geological features with fluid, sediment and hydrocarbon-enriched gas mixtures emitted from deep sedimentary environments. Without microbial attenuation in the water column, methane emission to atmosphere from terrestrial mud volcanoes constitutes a significant proportion to the global methane inventory. Microorganisms mediating methane transformation would be particularly enriched in such environments. Their activity, distribution, and diversity involved remain not well-constrained. At Shin-Yan-Ny-Hu Mud Volcanoes (SYNHMV) of southwestern Taiwan, we performed series of measurements and analyses on the pore water and eruptive water samples using geochemical and molecular approaches, in order to determine microbial processes and community assemblages responsible for methane transformation. Geochemical measurements indicated that sulfate depletion was companied with methane increase as the depth increased. Dissolved inorganic carbon (DIC) more depleted in 13C was observed at the depth of sulfate-methane transition zone (SMT, at ~12cm depth) than at other depth intervals. These characteristics of methane, sulfate, and DIC isotope profiles and the presence of ANME-1 sequences showed a high similarity with those of marine sediments, indicating the existence of active anaerobic oxidation of methane (AOM). From bottom to top, the increasing δ13C values of methane with the greatest value occurring in the eruptive surface water suggests methanogenesis and/or methane oxidation over the entire depth range. The contribution of microbial methane could be supported by molecular data of which methanogen-related archaea distributed throughout the entire depths, and the community structures were characterized by Methanosarcinales dominating at shallow depths and Methanomicrobiales dominating in deep sediments. The affinities and activities to substrate addition for methanogenesis appeared to be depth-dependent. Bacterial sequences affiliated with methane

  18. Biological hydrogen methanation - A review.

    PubMed

    Lecker, Bernhard; Illi, Lukas; Lemmer, Andreas; Oechsner, Hans

    2017-09-01

    Surplus energy out of fluctuating energy sources like wind and solar energy is strongly increasing. Biological hydrogen (H2) methanation (BHM) is a highly promising approach to move the type of energy from electricity to natural gas via electrolysis and the subsequent step of the Sabatier-reaction. This review provides an overview of the numerous studies concerning the topic of BHM. The technical and biological parameters regarding the research results of these studies are compared and analyzed hereafter. A holistic view on how to overcome physical limitations of the fermentation process, such as gas-liquid mass transfer or a rise of the pH value, and on the enhancement of environmental circumstances for the bacterial biomass are delivered within. With regards to ex-situ methanation, the evaluated studies show a distinct connection between methane production and the methane percentage in the off-gas. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Methane production in terrestrial arthropods

    SciTech Connect

    Hackstein, J.H.P.; Stumm, C.K. )

    1994-06-07

    The authors have screened more than 110 representatives of the different taxa of terrestrial arthropods for methane production in order to obtain additional information about the origins of biogenic methane. Methanogenic bacteria occur in the hindguts of nearly all tropical representatives of millipedes (Diplopoda), cockroaches (Blattaria), termites (Isoptera), and scarab beetles (Scarabaeidae), while such methanogens are absent from 66 other arthropod species investigated. Three types of symbiosis were found: in the first type, the arthropod's hindgut is colonized by free methanogenic bacteria; in the second type, methanogens are closely associated with chitinous structures formed by the host's hindgut; the third type is mediated by intestinal anaerobic protists with intracellular methanogens. Such symbiotic associations are likely to be a characteristic property of the particular taxon. Since these taxa represent many families with thousands of species, the world populations of methane-producing arthropods constitute an enormous biomass. The authors show that arthropod symbionts can contribute substantially to atmospheric methane.

  20. Titan ocean: Ethane, methane, nitrogen

    NASA Astrophysics Data System (ADS)

    Bell, Peter M.

    Detection of the atmosphere of Saturn's satellite Titan by the Voyager I spacecraft indicated an abundance of only 3 mol % methane (CH4). Recently J.I. Lunine, D.J. Stevenson, and Y.L. Yung calculated that 3 mol % methane is sufficiently low to preclude the stable coexistence of liquid methane on Titan's surface, which has a temperature of 94 K (Science, 222, 1229, 1983). Instead, Lunine et al. suggest that Titan's atmospheric methane may have broken down by a catalyzed photochemical reaction to ethane (C2H6). The resulting ocean would consist of a mixture of C2H6 and CH4 in the proportion of 3 to 1.

  1. Methane production in terrestrial arthropods.

    PubMed Central

    Hackstein, J H; Stumm, C K

    1994-01-01

    We have screened more than 110 representatives of the different taxa of terrestrial arthropods for methane production in order to obtain additional information about the origins of biogenic methane. Methanogenic bacteria occur in the hindguts of nearly all tropical representatives of millipedes (Diplopoda), cockroaches (Blattaria), termites (Isoptera), and scarab beetles (Scarabaeidae), while such methanogens are absent from 66 other arthropod species investigated. Three types of symbiosis were found: in the first type, the arthropod's hindgut is colonized by free methanogenic bacteria; in the second type, methanogens are closely associated with chitinous structures formed by the host's hindgut; the third type is mediated by intestinal anaerobic protists with intracellular methanogens. Such symbiotic associations are likely to be a characteristic property of the particular taxon. Since these taxa represent many families with thousands of species, the world populations of methane-producing arthropods constitute an enormous biomass. We show that arthropod symbionts can contribute substantially to atmospheric methane. Images PMID:8202505

  2. Estimating the tritiated hydrocarbon decontamination factor by heavy methane

    SciTech Connect

    James, B.J.; Nolen, R.L.; Hemphill, R.L.; Fuehrer, M.E.

    1988-09-01

    As part of the start up of Los Alamos National Laboratory's new tritium-handling facility, the efficiency of a catalytic oxidation tritium decontamination system was investigated using deuterated methane. The tests were performed during the start up of the facility to confirm the operability of the system before introducing tritium and to provide a baseline for comparison. Techniques and instruments normally used for atmospheric tracer experiments using deuterated methane were applied virtually without modification. The sensitivity of this method allowed preliminary checks at the sub-ppm (v/v) level.

  3. SAES ST909 Bench Scale Methane Cracking Tests

    SciTech Connect

    Klein, J.E.

    2000-12-15

    Tritium extracted from Commercial Light Water Reactor (CLWR) targets will be primarily hydrogen isotopes (tritium and protium), water, helium-4, and helium-3. Relatively low levels of impurities such as carbon monoxide, carbon dioxide, and methane are also expected in the extraction gas stream. Some methane is expected to have tritium substitution for some of the protium atoms. Tritiated ammonia is expected to form in some part of the extraction process due to the large size of the vacuum extraction furnace and the inevitable in-leakage of nitrogen from the secondary containment modules. These tritiated carbon and nitrogen species need to be processed to reduce tritium emissions from tritium processing facilities.

  4. Methane in well water from Lake Charles, Louisiana

    SciTech Connect

    Murray, H.E.; Beck, J.N. )

    1992-05-01

    The Chicot aquifer underlies all or parts of 13 parishes in Southwestern Louisiana. The uses of the aquifer include agricultural, industrial and provides nearly 100% of the potable water for the area. Southwestern Louisiana has a large natural gas industry and its associated distribution facilities. Agriculture is unique in this region in that there is extensive rice production and crawfish farming which results in large areas being seasonally flooded. Much of this coastal region consists of fresh and brackish marsh. Methane gas has been found in varying concentrations throughout the environment. Concentrations of 1.6 ppm in atmospheric samples were reported by Stauffer et al. (1985). Relatively high concentrations of dissolved methane have been reported to occur in natural ecosystems as a result of leakage of hydrocarbon deposits, and also from biogenic sources. In deep subsurface environments, such as groundwater, methanogenesis has also been reported. Often the presence of methane in these deep subsurface systems is due to waste leachate contamination. Methane can degas from groundwater and accumulate in wells or buildings thereby posing a potential explosion hazard. In addition, groundwater containing dissolved methane can serve as a primary energy source for the development of microbial communities. Gunsalus et al. (1962) reported substantial microbial growth at the air-water interface of a methane-supersaturated well system in which microbial oxidation of methane provided the necessary energy for microbial growth. Microbial growth within a well system could create taste and odor problems among other things that would directly affect water quality. 8 refs., 1 fig., 1 tab.

  5. Atmospheric Impact of Large Methane Emission in the Arctic Region

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, S.; Cameron-Smith, P. J.; Bergmann, D.; Reagan, M. T.; Collins, W.; Elliott, S. M.; Maltrud, M. E.

    2011-12-01

    A highly potent greenhouse gas, methane, is locked in the solid phase as ice-like deposits containing a mixture of water and gas (mostly methane) called clathrates, in ocean sediments and underneath permafrost regions. Clathrates are stable under high pressure and low temperatures. Recent estimates suggest that about 1600 - 2000GtC of clathrates are present in oceans and 400GtC in Arctic permafrost (Archer et al.2009) which is about 4000 times that of current annual emissions. In a warming climate, increase in ocean temperatures could alter the geothermal gradient, which in turn could lead to dissociation of the clathrates and release of methane into the ocean and subsequently into the atmosphere as well. This could be of particular importance in the shallow part of the Arctic Ocean where the clathrates are found in depths of only 300m. In this presentation, we shall show results from our ongoing simulation of a scenario of large scale methane outgassing from clathrate dissociation due to warming ocean temperatures in the Arctic based on ocean sediment modeling. To that end we use the CESM (Community Earth System Model) version 1 with fully active coupled atmosphere-ocean-land model together with fast atmospheric chemistry module to simulate the response to increasing methane emissions in the Barents Sea, Canadian Archipelago and the Sea of Okhotsk. The simulation shows the effect these methane emissions could have on global surface methane, surface ozone, surface air temperature and other related indices. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-491764

  6. IUPAC-NIST Solubility Data Series. 100. Rare Earth Metal Fluorides in Water and Aqueous Systems. Part 2. Light Lanthanides (Ce–Eu)

    SciTech Connect

    Mioduski, Tomasz; Gumiński, Cezary; Zeng, Dewen

    2015-03-15

    This is the second part of the volume devoted to the evaluation of experimental solubility data for rare earth metal (REM) fluorides in water as well as in aqueous ternary and multicomponent systems. Fluorides of Ce, Pr, Nd, Pm, Sm, and Eu (so-called light lanthanides), as the main solutes, are covered in the present part, which has thorough coverage of the experimental literature through the end of 2012. The experimentally unknown solubility value for PmF{sub 3} in water was predicted by an interpolation of the solubility values for NdF{sub 3} and SmF{sub 3} at 298 K. General features of the systems, such as the nature of the equilibrium solid phases, solubility as a function of temperature, influence of ionic strength, pH, mixed solvent medium on the solubility, quality of the solubility results, and solubility as a function of REM atomic number, have already been presented in Part 1 of the volume.

  7. Methane emissions from MBT landfills

    SciTech Connect

    Heyer, K.-U. Hupe, K.; Stegmann, R.

    2013-09-15

    Highlights: • Compilation of methane generation potential of mechanical biological treated (MBT) municipal solid waste. • Impacts and kinetics of landfill gas production of MBT landfills, approach with differentiated half-lives. • Methane oxidation in the waste itself and in soil covers. • Estimation of methane emissions from MBT landfills in Germany. - Abstract: Within the scope of an investigation for the German Federal Environment Agency (“Umweltbundesamt”), the basics for the estimation of the methane emissions from the landfilling of mechanically and biologically treated waste (MBT) were developed. For this purpose, topical research including monitoring results regarding the gas balance at MBT landfills was evaluated. For waste treated to the required German standards, a methane formation potential of approximately 18–24 m{sup 3} CH{sub 4}/t of total dry solids may be expected. Monitoring results from MBT landfills show that a three-phase model with differentiated half-lives describes the degradation kinetics in the best way. This is due to the fact that during the first years of disposal, the anaerobic degradation processes still proceed relatively intensively. In addition in the long term (decades), a residual gas production at a low level is still to be expected. Most of the soils used in recultivation layer systems at German landfills show a relatively high methane oxidation capacity up to 5 l CH{sub 4}/(m{sup 2} h). However, measurements at MBT disposal sites indicate that the majority of the landfill gas (in particular at non-covered areas), leaves the landfill body via preferred gas emission zones (hot spots) without significant methane oxidation. Therefore, rather low methane oxidation factors are recommended for open and temporarily covered MBT landfills. Higher methane oxidation rates can be achieved when the soil/recultivation layer is adequately designed and operated. Based on the elaborated default values, the First Order Decay (FOD

  8. Methane Propulsion Elements for Mars

    NASA Technical Reports Server (NTRS)

    Percy, Tom; Polsgrove, Tara; Thomas, Dan

    2017-01-01

    Human exploration beyond LEO relies on a suite of propulsive elements to: (1) Launch elements into space, (2) Transport crew and cargo to and from various destinations, (3) Provide access to the surface of Mars, (4) Launch crew from the surface of Mars. Oxygen/Methane propulsion systems meet the unique requirements of Mars surface access. A common Oxygen/Methane propulsion system is being considered to reduce development costs and support a wide range of primary & alternative applications.

  9. Methane generation from animal wastes

    SciTech Connect

    Fulton, E.L.

    1980-06-01

    The conversion of manure to biogas via anaerobic digestion is described. The effluent resulting from the conversion retains fertilizer value and is environmentally acceptable. Discussion is presented under the headings: methane formation in the digester; the Tarleton State Poultry Waste to Methane production system; operating experience at Tarleton State; economics of biogas production from poultry waste; construction cost and biogas value; energy uses; feed and waste processing; and advantages of anaerobic digestion. (DMC)

  10. Methane production in Minnesota peatlands

    SciTech Connect

    Williams, R.T.; Crawford, R.L.

    1984-06-01

    Rates of methane production in Minnesota peats were studied. Surface (10- to 25-cm) peats produced an average of 228 nmol of CH/sub 4/ per g (dry weight) per h at 25/sup 0/C and ambient pH. Methanogenesis rates generally decreased with depth in ombrotrophic peats, but on occasion were observed to rise within deeper layers of certain fen peats. Methane production was temperature dependent, increasing with increasing temperature (4 to 30/sup 0/C), except in peats from deeper layers. Maximal methanogenesis from these deeper regions occurred at 12/sup 0/C. Methane production rates were also pH dependent. Two peats with pHs of 3.8 and 4.3 had an optimum rate of methane production at pH 6.0. The addition to peat of glucose and H/sub 2/-CO/sub 2/ stimulated methanogenesis, whereas the addition of acetate inhibited methanogenesis. Cysteine-sulfide, nitrogen-phosphorus-trace metals, and vitamins-yeast extract affected methane production very little. Various gases were found to be trapped or dissolved (or both) within peatland waters. Dissolved methane increased linearly to a depth of 210 cm. The accumulation of metabolic end products produced within peat bogs appears to be an important mechanism limiting turnover in peatland environments.

  11. Modelling an experimental methane fuel processor

    NASA Astrophysics Data System (ADS)

    Lin, Shi-Tin; Chen, Yih-Hang; Yu, Cheng-Ching; Liu, Yen-Chun; Lee, Chiou-Hwang

    Steady-state models are developed to describe an experimental methane fuel processor that is intended to provide hydrogen for a fuel cell system for power generation (2-3 kW). First-principle reactor models are constructed to describe a series of reactions, i.e., steam and autothermal reforming (SR/ATR), high- and low-temperature water-gas shift (HTS/LTS) reactions and preferential oxidation (PROX) reactions, at different sectors of the reactor system for methane reforming as well as gas cleaning. The pre-exponential factors of the rate constants are adjusted to fit the experimental data and the resultant reactor model provides a reasonably good description of steady-state behaviour. Next, sensitivity analyses are performed to locate the optimum operating point of the fuel processor. The objective function of the optimization is fuel processor efficiency. The dominating optimization variables include: the ratios of water and oxygen to the hydrocarbon feed to the autothermal reforming reactor and the inlet temperature of the reactor. The results indicate that further improvement in fuel processor efficiency can be made with a reliable process model.

  12. Experimental determination of methane dissolution from simulated subsurface oil leakages

    NASA Astrophysics Data System (ADS)

    Sauthoff, W.; Peltzer, E. T.; Walz, P. M.; Brewer, P. G.

    2013-12-01

    Subsurface oil leakages and increased offshore drilling efforts have raised concern over the fate of hydrocarbon mixtures of oil and gas in ocean environments. Recent wellhead and pipeline failures in the Gulf of Mexico are extreme examples of this problem. Understanding the mechanism and rate of vertical transport of hydrocarbon chemical species is necessary to predict the environmental impact of subsurface leakages. In a series of controlled experiments, we carried out a deep-sea field experiment in Monterey Canyon to investigate the behavior of a gas-saturated liquid hydrocarbon mass rising from the seafloor. Aboard the R/V Rachel Carson, we used the ROV Ventana to transport a laboratory prepared volume of decane (C10H22) saturated with methane gas (CH4) to mimic a subsurface seafloor discharge. We released the oil and gas mixture into a vertically oriented open bottom glass tube followed by methane loss rate measurements both at discrete depths, and during rapid, continuous vehicle ascent from 800 to 100 m water depth to monitor changes in dissolution and bubble nucleation. Using laser Raman techniques and HD video we quantified the chemical state of the hydrocarbon fluid, including rate of methane gas dissolution. The primary methane Raman peak was readily observable within the decane C-H stretching complex. Variation in the amount of gas dissolved in the oil greatly influences oil plume density and in turn oil plume vertical rise rate. Our results show that the rise rate of the hydrocarbon mass significantly exceeds the rate at which the excess methane was lost by dissolution. This result implies that vertical transport of methane in the saturated hydrocarbon liquid phase can greatly exceed a gas bubble plume ascending the water column from a seafloor source. These results and observations may be applicable to improved understanding of the composition, distribution, and environmental fate of leaked hydrocarbon mixtures and inform remediation efforts.

  13. Manganese- and iron-dependent marine methane oxidation.

    PubMed

    Beal, Emily J; House, Christopher H; Orphan, Victoria J

    2009-07-10

    Anaerobic methanotrophs help regulate Earth's climate and may have been an important part of the microbial ecosystem on the early Earth. The anaerobic oxidation of methane (AOM) is often thought of as a sulfate-dependent process, despite the fact that other electron acceptors are more energetically favorable. Here, we show that microorganisms from marine methane-seep sediment in the Eel River Basin in California are capable of using manganese (birnessite) and iron (ferrihydrite) to oxidize methane, revealing that marine AOM is coupled, either directly or indirectly, to a larger variety of oxidants than previously thought. Large amounts of manganese and iron are provided to oceans from rivers, indicating that manganese- and iron-dependent AOM have the potential to be globally important.

  14. Geoscience in Support of a Mars Methane Analogue Mission

    NASA Astrophysics Data System (ADS)

    Boivin, Alexandre

    The Mars Methane Analogue Mission, funded by the Canadian Space Agency through its Analogue Missions program, simulates a Mars rover mission whose purpose is to detect, analyse, and determine the source of methane emissions on the planet's surface. As part of this project, both an electromagnetic induction sounder (EMIS) and a high-resolution triangulation-based 3D laser scanner were tested in the field to demonstrate the benefit of including these instruments on future rover missions. EMIS data was inverted in order to derive information on the conductivity and magnetic susceptibility of the near subsurface. 3D laser scanner data was processed with fracture detection as a goal in order to simplify the search for areas of potential methane seepage. Both instruments were found to be very valuable for future rover missions of this type.

  15. The permeation of methane molecules through silicalite-1 surfaces.

    PubMed

    Thompho, Somphob; Chanajaree, Rungroj; Remsungnen, Tawun; Hannongbua, Supot; Bopp, Philippe A; Fritzsche, Siegfried

    2009-03-12

    The permeation of methane molecules through the silicalite-1 surfaces with and without silanol groups has been studied by nonequilibrium molecular dynamics computer simulations. A newly fitted intermolecular potential between the methane molecules and the silanol is used. A control volume provides a nearly stationary gas phase close to the membrane. The nonequilibrium process of filling the (initially empty) membrane with methane molecules until saturation is considered, and the surface permeability has been evaluated. It turns out to be strongly influenced by the presence of silanol groups. Additionally it was found that for a large part of the loading process the particle stream into the zeolite membrane was nearly independent upon the deviation from equilibrium. This means that far from equilibrium the decay of this deviation does not follow an exponential law.

  16. SeaWiFS technical report series. Volume 13: Case studies for SeaWiFS calibration and validation, part 1

    NASA Technical Reports Server (NTRS)

    Hooker, Stanford B. (Editor); Firestone, Elaine R. (Editor); Mcclain, Charles R.; Comiso, Josefino C.; Fraser, Robert S.; Firestone, James K.; Schieber, Brian D.; Yeh, Eueng-Nan; Arrigo, Kevin R.; Sullivan, Cornelius W.

    1994-01-01

    Although the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Calibration and Validation Program relies on the scientific community for the collection of bio-optical and atmospheric correction data as well as for algorithm development, it does have the responsibility for evaluating and comparing the algorithms and for ensuring that the algorithms are properly implemented within the SeaWiFS Data Processing System. This report consists of a series of sensitivity and algorithm (bio-optical, atmospheric correction, and quality control) studies based on Coastal Zone Color Scanner (CZCS) and historical ancillary data undertaken to assist in the development of SeaWiFS specific applications needed for the proper execution of that responsibility. The topics presented are as follows: (1) CZCS bio-optical algorithm comparison, (2) SeaWiFS ozone data analysis study, (3) SeaWiFS pressure and oxygen absorption study, (4) pixel-by-pixel pressure and ozone correction study for ocean color imagery, (5) CZCS overlapping scenes study, (6) a comparison of CZCS and in situ pigment concentrations in the Southern Ocean, (7) the generation of ancillary data climatologies, (8) CZCS sensor ringing mask comparison, and (9) sun glint flag sensitivity study.

  17. Series: The research agenda for general practice/family medicine and primary health care in Europe. Part 5: Needs and implications for future research and policy.

    PubMed

    van Royen, Paul; Beyer, Martin; Chevallier, Patrick; Eilat-Tsanani, Sophia; Lionis, Christos; Peremans, Lieve; Petek, Davorina; Rurik, Imre; Soler, Jean Karl; Stoffers, Henri E J H; Topsever, Pinar; Ungan, Mehmet; Hummers-Pradier, Eva

    2010-12-01

    The recently published 'Research Agenda for General Practice/Family Medicine and Primary Health Care in Europe' summarizes the evidence relating to the core competencies and characteristics of the Wonca Europe definition of GP/FM, and highlights related needs and implications for future research and policy. The European Journal of General Practice publishes a series of articles based on this document. In a first article, background, objectives, and methodology were discussed. In three subsequent, articles the results for the six core competencies of the European Definition of GP/FM were presented. This article formulates the common aims for further research and appropriate research methodologies, based on the missing evidence and research gaps identified form the comprehensive literature review. In addition, implications of this research agenda for general practitioners/family doctors, researchers, research organizations, patients and policy makers are presented. The concept of six core competencies should be abandoned in favour of a model with four dimensions, including clinical, person related, community oriented and management aspects. Future research and policy should consider more the involvement and rights of patients; more attention should be given to how new treatments or technologies are effectively translated into routine patient care, in particular primary care. There is a need for a European ethics board. The promotion of GP/FM research demands a good infrastructure in each country, including access to literature and databases, appropriate funding and training possibilities.

  18. SeaWiFS technical report series. Volume 27: Case studies for SeaWiFS calibration and validation, part 3

    NASA Technical Reports Server (NTRS)

    Hooker, Stanford B. (Editor); Firestone, Elaine R. (Editor); Acker, James G. (Editor); Mueller, J. L.; Fraser, R. S.; Biggar, S. F.; Thome, K. J.; Slater, P. N.; Holmes, A. W.; Barnes, R. A.

    1995-01-01

    This document provides brief reports, or case studies, on a number of investigations sponsored by the Calibration and Validation Team (CVT) within the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Project. Chapter I describes a comparison of the irradiance immersion coefficients determined for several different marine environmental radiometers (MERs). Chapter 2 presents an analysis of how light absorption by atmospheric oxygen will influence the radiance measurements in band 7 of the SeaWiFS instrument. Chapter 3 gives the results of the second ground-based solar calibration of the instrument, which was undertaken after the sensor was modified to reduce the effects of internal stray light. (The first ground-based solar calibration of SeaWiFS is described in Volume 19 in the SeaWiFS Technical Report Series.) Chapter 4 evaluates the effects of ship shadow on subsurface irradiance and radiance measurements deployed from the deck of the R/V Weatherbird 11 in the Atlantic Ocean near Bermuda. Chapter 5 illustrates the various ways in which a single data day of SeaWiFS observations can be defined, and why the spatial definition is superior to the temporal definition for operational usage.

  19. SeaWiFS technical report series. Volume 20: The SeaWiFS bio-optical archive and storage system (SeaBASS), part 1

    NASA Technical Reports Server (NTRS)

    Hooker, Stanford B. (Editor); Mcclain, Charles R.; Firestone, James K.; Westphal, Todd L.; Yeh, Eueng-Nan; Ge, Yuntao; Firestone, Elaine R.

    1994-01-01

    This document provides an overview of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Bio-Optical Archive and Storage System (SeaBASS), which will serve as a repository for numerous data sets of interest to the SeaWiFS Science Team and other approved investigators in the oceanographic community. The data collected will be those data sets suitable for the development and evaluation of bio-optical algorithms which include results from SeaWiFS Intercalibration Round-Robin Experiments (SIRREXs), prelaunch characterization of the SeaWiFS instrument by its manufacturer -- Hughes/Santa Barbara Research Center (SBRC), Marine Optical Characterization Experiment (MOCE) cruises, Marine Optical Buoy (MOBY) deployments and refurbishments, and field studies of other scientists outside of NASA. The primary goal of the data system is to provide a simple mechanism for querying the available archive and requesting specific items, while assuring that the data is made available only to authorized users. The design, construction, and maintenance of SeaBASS is the responsibility of the SeaWiFS Calibration and Validation Team (CVT). This report is concerned with documenting the execution of this task by the CVT and consists of a series of chapters detailing the various data sets involved. The topics presented are as follows: 1) overview of the SeaBASS file architecture, 2) the bio-optical data system, 3) the historical pigment database, 4) the SIRREX database, and 5) the SBRC database.

  20. Quantification of Methane Emissions From Street Level Data

    NASA Astrophysics Data System (ADS)

    Prasad, K.; Cambaliza, M. L.; Lavoie, T. N.; Salmon, O. E.; Shepson, P. B.; Lauvaux, T.; Davis, K. J.; Whetstone, J. R.

    2013-12-01

    The problem of identifying, attributing, and quantifying methane emissions from urban sources such as landfills, waste-water treatment facilities and natural gas distribution systems is an active area of research. This interest is fueled, in part, by recent measurements indicating that urban emissions are a significant source of methane (CH4, a potent greenhouse gas) and in fact may be substantially higher than current inventory estimates. As a result, developing methods for locating and quantifying emissions from urban methane sources is of great interest to industries such as landfill owners, and governmental agencies. In an attempt to identify major methane source locations and emissions in the city of Indianapolis, systematic measurements of CH4 concentrations and meteorology data were made at street level using multiple vehicles equipped with cavity ring-down spectrometers. A number of discrete sources were detected at methane molar ratios in excess of 15 times background levels. The street level data is analyzed with plume inversion models including Weather Research and Forecasting (WRF) software, Fire Dynamics Simulator (FDS) and backward Lagrangian Simulations (bLS) to identify source location and emission rates. The methodology for analyzing the street level data and our estimates of CH4 emissions from various sources in the city of Indianapolis will be presented.

  1. 49 new T dwarfs identified using methane imaging

    NASA Astrophysics Data System (ADS)

    Cardoso, C. V.; Burningham, B.; Smart, R. L.; van Spaandonk, L.; Baker, D.; Smith, L. C.; Zhang, Z. H.; Andrei, A. H.; Bucciarelli, B.; Dhital, S.; Jones, H. R. A.; Lattanzi, M. G.; Magazzú, A.; Pinfield, D. J.; Tinney, C. G.

    2015-07-01

    We present the discovery of 49 new photometrically classified T dwarfs from the combination of large infrared and optical surveys combined with follow-up Telescopio Nazionale Galileo photometry. We used multiband infrared and optical photometry from the United Kingdom Infrared Telescope and Sloan Digital Sky Surveys to identify possible brown dwarf candidates, which were then confirmed using methane filter photometry. We have defined a new photometric conversion between CH4s - CH4l colour and spectral type for T4-T8 brown dwarfs based on a part of the sample that has been followed up using methane photometry and spectroscopy. Using methane differential photometry as a proxy for spectral type for T dwarfs has proved to be a very efficient technique. Of a subset of 45 methane selected brown dwarfs that were observed spectroscopically, 100 per cent were confirmed as T dwarfs. Future deep imaging surveys will produce large samples of faint brown dwarf candidates, for which spectroscopy will not be feasible. When broad wavelength coverage is unavailable, methane imaging offers a means to efficiently classify candidates from such surveys using just a pair of near-infrared images.

  2. SWANA/NREL/DOE landfill methane model development project

    SciTech Connect

    Augenstein, D.; Vogt, W.G.; Demers, S.T.

    1996-11-01

    Landfill methane models are widely used to project landfill methane (gas) generation and recovery, as well as landfill emissions to the atmosphere. While several models are used in the landfill gas industry and elsewhere, their {open_quotes}validation{close_quotes} is still, at best, limited. Validation is, simply, adjusting model parameters so that models best project methane recovery field data, or else, demonstrating that models project methane recovery actually experienced. Limited data have been used to develop most models. In addition, models have generally validated methane recovery against projections over relatively short intervals or at only single {open_quotes}points in time{close_quotes} whereas comparisons over longer terms would be desirable. Thus, confidence limits to be assigned to model projections are in large part unknown. In addition, failures of models have been (if anecdotally) reported. In some cases, energy equipment has been installed and left idle reportedly because landfill gas has been less than expected. In light of this situation, this project`s purpose has been to verify and validate models based on data from a greater number of landfills in the past, using gas recovery data over longer terms (several years when possible). Another objective is to use these data to develop a better estimate of key parameters, yield and kinetic coefficients, and associated confidence limits which may be assigned to model projections.

  3. Russian boreal peatlands dominate the natural European methane budget

    NASA Astrophysics Data System (ADS)

    Schneider, Julia; Jungkunst, Hermann F.; Wolf, Ulrike; Schreiber, Peter; Gažovič, Michal; Miglovets, Mikhail; Mikhaylov, Oleg; Grunwald, Dennis; Erasmi, Stefan; Wilmking, Martin; Kutzbach, Lars

    2016-01-01

    About 60% of the European wetlands are located in the European part of Russia. Nevertheless, data on methane emissions from wetlands of that area are absent. Here we present results of methane emission measurements for two climatically different years from a boreal peatland complex in European Russia. Winter fluxes were well within the range of what has been reported for the peatlands of other boreal regions before, but summer fluxes greatly exceeded the average range of 5-80 mg CH4 m-2 d-1 for the circumpolar boreal zone. Half of the measured fluxes ranged between 150 and 450 mg CH4 m-2 d-1. Extrapolation of our data to the whole boreal zone of European Russia shows that theses emissions could amount to up to 2.7 ± 1.1 Tg CH4 a-1, corresponding to 69% of the annual emissions from European wetlands or 33% of the total annual natural European methane emission. In 2008, climatic conditions corresponded to the long term mean, whereas the summer of 2011 was warmer and noticeably drier. Counterintuitively, these conditions led to even higher CH4 emissions, with peaks up to two times higher than the values measured in 2008. As Russian peatlands dominate the areal extend of wetlands in Europe and are characterized by very high methane fluxes to the atmosphere, it is evident, that sound European methane budgeting will only be achieved with more insight into Russian peatlands.

  4. Investigation of the Methane Hydrate Formation by Cavitation Jet

    NASA Astrophysics Data System (ADS)

    Morita, H.; Nagao, J.

    2015-12-01

    Methane hydrate (hereafter called "MH") is crystalline solid compound consisting of hydrogen-bonded water molecules forming cages and methane gas molecules enclosed in the cage. When using MH as an energy resource, MH is dissociated to methane gas and water and collect only the methane gas. The optimum MH production method was the "depressurization method". Here, the production of MH means dissociating MH in the geologic layers and collecting the resultant methane gas by production systems. In the production of MH by depressurization method, MH regeneration was consider to important problem for the flow assurance of MH production system. Therefore, it is necessary to clarify the effect of flow phenomena in the pipeline on hydrate regeneration. Cavitation is one of the flow phenomena which was considered a cause of MH regeneration. Large quantity of microbubbles are produced by cavitation in a moment, therefore, it is considered to promote MH formation. In order to verify the possible of MH regeneration by cavitation, it is necessary to detailed understanding the condition of MH formation by cavitation. As a part of a Japanese National hydrate research program (MH21, funded by METI), we performed a study on MH formation using by cavitation. The primary objective of this study is to demonstrate the formation MH by using cavitation in the various temperature and pressure condition, and to clarify the condition of MH formation by using observation results.

  5. Is methane a new therapeutic gas?

    PubMed Central

    2012-01-01

    Background Methane is an attractive fuel. Biologically, methanogens in the colon can use carbon dioxide and hydrogen to produce methane as a by-product. It was previously considered that methane is not utilized by humans. However, in a recent study, results demonstrated that methane could exert anti-inflammatory effects in a dog small intestinal ischemia-reperfusion model. Point of view Actually, the bioactivity of methane has been investigated in gastrointestinal diseases, but the exact mechanism underlying the anti-inflammatory effects is required to be further elucidated. Methane can cross the membrane and is easy to collect due to its abundance in natural gas. Although methane is flammable, saline rich in methane can be prepared for clinical use. These seem to be good news in application of methane as a therapeutic gas. Conclusion Several problems should be resolved before its wide application in clinical practice. PMID:23009320

  6. IUPAC-NIST Solubility Data Series. 100. Rare Earth Metal Fluorides in Water and Aqueous Systems. Part 3. Heavy Lanthanides (Gd–Lu)

    SciTech Connect

    Mioduski, Tomasz; Gumiński, Cezary; Zeng, Dewen

    2015-06-15

    This is the third part of the volume devoted to solubility data for the rare earth metal (REM) fluorides in water and in aqueous ternary and multicomponent systems. It covers experimental results of trivalent fluorides of Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu (so-called heavy lanthanides), since no quantitative data on solubilities of TbF{sub 4} and YbF{sub 2} (the most stable compounds at these valencies) are available. The related literature has been covered through the end of 2014. Compilations of all available papers with the solubility data are introduced for each REM fluoride with a corresponding critical evaluation. Every such assessment contains a collection of all solubility results in aqueous solution, a selection of suggested solubility data, a solubility equation, and a brief discussion of the multicomponent systems. Only simple fluorides (no complexes or double salts) are treated as the input substances in this report. General features of the systems, such as nature of the equilibrium solid phases, solubility as a function of temperature, influence of ionic strength, solution pH, mixed solvent medium on the solubility, quality of the solubility results, and the solubility as a function of REM atomic number, have already been presented in Part 1 of the volume.

  7. IUPAC-NIST Solubility Data Series. 100. Rare Earth Metal Fluorides in Water and Aqueous Systems. Part 3. Heavy Lanthanides (Gd-Lu)

    NASA Astrophysics Data System (ADS)

    Mioduski, Tomasz; Gumiński, Cezary; Zeng, Dewen

    2015-06-01

    This is the third part of the volume devoted to solubility data for the rare earth metal (REM) fluorides in water and in aqueous ternary and multicomponent systems. It covers experimental results of trivalent fluorides of Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu (so-called heavy lanthanides), since no quantitative data on solubilities of TbF4 and YbF2 (the most stable compounds at these valencies) are available. The related literature has been covered through the end of 2014. Compilations of all available papers with the solubility data are introduced for each REM fluoride with a corresponding critical evaluation. Every such assessment contains a collection of all solubility results in aqueous solution, a selection of suggested solubility data, a solubility equation, and a brief discussion of the multicomponent systems. Only simple fluorides (no complexes or double salts) are treated as the input substances in this report. General features of the systems, such as nature of the equilibrium solid phases, solubility as a function of temperature, influence of ionic strength, solution pH, mixed solvent medium on the solubility, quality of the solubility results, and the solubility as a function of REM atomic number, have already been presented in Part 1 of the volume.

  8. Legends Lecture Series III

    NASA Image and Video Library

    2011-07-27

    Marina Benigno (far right) at Stennis Space Center, welcomes former administrative assistants and secretaries to the third Legends Lecture Series session. Lecture participants spoke about their work experiences with Stennis directors and deputy directors. Panel participants included Janet Austill (l to r), Mary Lou Matthews, Helen Paul, Wanda Howard, Ann Westendorf and Mary Gene Dick. The Legends Lecture Series is part of a yearlong celebration of the 50th anniversary of Stennis Space Center.

  9. Methane and radioactive isotopes in submarine hydrothermal systems

    SciTech Connect

    Kim, K.R.

    1983-01-01

    This thesis consists of two parts: 1) methane and 2) radioactive isotopes, especially radon, in submarine hydrothermal systems. Both parts deal with the use of these gases as tracers for mapping hydrothermal vents at sea, and with their relationships to other sensitive tracers such as helium, manganese, and temperature. Hydrothermal methane was used as a real-time tracer for locating new submarine hydrothermal systems along spreading axes, discovering new hydrothermal systems at two locations in Pacific Ocean: 1) 20/sup 0/S on East Pacific Rise, and 2) Mariana Trough Back-arc Basin. Methane shows good correlations with helium-3 and temperature with similar ratios in various hydrothermal systems, 3 to 42 x 10/sup 6/ for the methane to helium-3 ratio, and 3 to 19 ..mu.. cc/kg/sup 0/C for the methane to temperature anomaly. These similar ratios from different areas provide evidence for chemical homogeneity of submarine hydrothermal waters. A good correlation between methane and manganese appears to be associated only with high-temperature hydrothermal systems. Radioisotopes in the vent waters of 21/sup 0/N high-temperature hydrothermal system have end-member concentrations of 7.5 to 40 dpm/kg for Ra-226, 360 dpm/kg for Rn 222, 62 dpm/kg for Pb-210, and 19 dpm/kg for Po-210. The radon activity for this system is one order of magnitude lower, and the Pb-210 activity is one order or magnitude higher, than those a the low temperature Galapagos system. All these observations suggest that the high radon, and low Pb-210 activity observed in Galapagos system may originate from the extensive subsurface mixing and water-rock interaction in this system (direct injection of radon and scavenging of Pb-210).

  10. The significance of methane ebullition

    NASA Astrophysics Data System (ADS)

    Walter, K.; Draluk, D. A.; Zimov, S. A.; Chapin, T.

    2003-12-01

    Ebullition is often the dominant pathway of methane release from aquatic ecosystems, yet it has seldom been carefully measured, due to heterogeneity in the spatial distribution and episodic release of gas bubbles. This likely results in an underestimation of total methane emission. We took advantage of ice formation over lake surfaces in NE Siberia to map patterns of ebullition. As ice forms in autumn, bubbles released from lake sediments are continually trapped under the ice at the water surface resulting in stacks of bubbles separated by thin films of ice called `koshkas'. Mapping the distribution of koshkas enabled us to identify `background' patterns of ebullition. In addition, we located `hot-spot' ebullition sites that remain permanently open throughout winter due to exceptionally high rates of methane bubbling. We used random and selective placement of underwater/ under-ice chambers to measure `background' and `hot-spot' fluxes annually. The combination of mapping and chamber measurements among different types of lakes and along lake margins varying in intensity of thermokarst erosion or aquatic plant growth enabled us to 1) improve estimates of total methane emissions from NE Siberian lakes, and to 2) identify landscape processes (thermokarst erosion vs. wetland mat formation) that enhance methane production and emission. Ignoring the contribution from hotspots, background ebullition comprised more than 75% of total methane emissions from lakes. From hotspot sites we measured up to 10-L m-2 of methane per day in early summer. Although hotspots comprised roughly 0.05% of the area along thermokarst margins, where they were most common, ebullition from hotspots contributed approximately 69% of the total ebullition flux. Including the flux from hotspots could increase estimates of CH4 ebullition from thermokarst margins 300%! Thermokarst lakes in Russia comprise a large proportion of the world's high latitude lakes; yet they are understudied. North Siberian

  11. Virtual Breakthrough Series, Part 1: Preventing Catheter-Associated Urinary Tract Infection and Hospital-Acquired Pressure Ulcers in the Veterans Health Administration.

    PubMed

    Zubkoff, Lisa; Neily, Julia; King, Beth J; Dellefield, Mary Ellen; Krein, Sarah; Young-Xu, Yinong; Boar, Shoshana; Mills, Peter D

    2016-11-01

    In 2014 the Veterans Health Administration (VHA) of the Department of Veterans Affairs (VA) implemented a Virtual Breakthrough Series (VBTS) collaborative to help VHA facilities prevent hospital-acquired conditions: catheter-associated urinary tract infection (CAUTI) and hospital-acquired pressure ulcers (HAPUs). During the prework phase, participating facilities assembled a multidisciplinary team, assessed their current system for CAUTI or HAPU prevention, and examined baseline data to set improvement aims. The action phase consisted of educational conference calls, coaching, and monthly team reports. Learning was conducted via phone, web-based options, and e-mail. The CAUTI bundle focused on four key principles: (1) avoidance of indwelling urinary catheters, (2) proper insertion technique, (3) proper catheter maintenance, and (4) timely removal of the indwelling catheter. The HAPU bundle focused on assessment and inspection, pressure-relieving surfaces, turning and repositioning, incontinence management, and nutrition/hydration assessment and intervention. For the 18 participating units, the mean aggregated CAUTI rate decreased from 2.37 during the prework phase to 1.06 per 1,000 catheter-days during the action (implementation) phase (p < 0.001); the rate did not change for CAUTI nonparticipating sites. HAPU data were available only for 21 of the 31 participating units, whose mean aggregated HAPU rate decreased from 1.80 to 0.99 from prework to continuous improvement (p < 0.001). Staff education and documentation improvement were the most frequently implemented changes. This project helped improve CAUTI and HAPU rates in the VHA and presents a promising model for implementing a virtual model for improvement. Copyright 2016 The Joint Commission.

  12. Effects of monovalent anions of the hofmeister series on DPPC lipid bilayers Part II: modeling the perpendicular and lateral equation-of-state.

    PubMed

    Leontidis, E; Aroti, A; Belloni, L; Dubois, M; Zemb, T

    2007-09-01

    The effects of Hofmeister anions on the perpendicular and lateral equation-of-state (EOS) of the dipalmitoylphosphatidylcholine lamellar phase discussed in the companion article are here examined using appropriate free energy models for the intra- and interbilayer interactions. Minimizing the free energy with respect to the two basic geometrical parameters of the lamellar phase, which are the interbilayer water thickness, d(w), and the lipid headgroup area, a(L), provides the perpendicular (osmotic pressure balance) and lateral EOS. Standard models were used for the hydration, undulation, and Van der Waals attractive force between the bilayers in the presence of electrolytes whereas two alternative treatments of electrostatic interactions were used to obtain "binding" or "partitioning" constants of anions to the lipid bilayers both in the absence and in the presence of sodium binding. The computed binding constants depend on anion type and follow the Hofmeister series, but were found to increase with electrolyte concentration, implying that the local binding approximation cannot fit bilayer repulsion data. The partitioning model was also found inadequate at high electrolyte concentrations. The fitting attempts revealed two additional features worthy of future investigation. First, at maximum swelling in the presence of electrolytes the osmotic pressure of the bilayer system cannot be set equal to zero. Second, at high salt concentrations an additional repulsion appears to come into effect in the presence of strongly adsorbing anions such as I(-) or SCN(-). Both these phenomena may reflect an inconsistent treatment of the ion-surface interactions, which have an impact on the osmotic pressure. Alternatively, they may arise from bulk solution nonidealities that cannot be handled by the classical Poisson-Boltzmann formalism. The inability of current models to explain the "lateral" EOS by fitting the area per lipid headgroup as a function of salt type and concentration

  13. Effects of Monovalent Anions of the Hofmeister Series on DPPC Lipid Bilayers Part II: Modeling the Perpendicular and Lateral Equation-of-State

    PubMed Central

    Leontidis, E.; Aroti, A.; Belloni, L.; Dubois, M.; Zemb, T.

    2007-01-01

    The effects of Hofmeister anions on the perpendicular and lateral equation-of-state (EOS) of the dipalmitoylphosphatidylcholine lamellar phase discussed in the companion article are here examined using appropriate free energy models for the intra- and interbilayer interactions. Minimizing the free energy with respect to the two basic geometrical parameters of the lamellar phase, which are the interbilayer water thickness, dw, and the lipid headgroup area, aL, provides the perpendicular (osmotic pressure balance) and lateral EOS. Standard models were used for the hydration, undulation, and Van der Waals attractive force between the bilayers in the presence of electrolytes whereas two alternative treatments of electrostatic interactions were used to obtain “binding” or “partitioning” constants of anions to the lipid bilayers both in the absence and in the presence of sodium binding. The computed binding constants depend on anion type and follow the Hofmeister series, but were found to increase with electrolyte concentration, implying that the local binding approximation cannot fit bilayer repulsion data. The partitioning model was also found inadequate at high electrolyte concentrations. The fitting attempts revealed two additional features worthy of future investigation. First, at maximum swelling in the presence of electrolytes the osmotic pressure of the bilayer system cannot be set equal to zero. Second, at high salt concentrations an additional repulsion appears to come into effect in the presence of strongly adsorbing anions such as I− or SCN−. Both these phenomena may reflect an inconsistent treatment of the ion-surface interactions, which have an impact on the osmotic pressure. Alternatively, they may arise from bulk solution nonidealities that cannot be handled by the classical Poisson-Boltzmann formalism. The inability of current models to explain the “lateral” EOS by fitting the area per lipid headgroup as a function of salt type and

  14. Methane gas concentration in soils and ground water, Carbon and Emery Counties, Utah, 1995-2003

    USGS Publications Warehouse

    Stolp, B.J.; Burr, A.L.; Johnson, K.K.

    2006-01-01

    The release of methane gas from coal beds creates the potential for it to move into near-surface environments through natural and human-made pathways. To help ensure the safety of communities and determine the potential effects of development of coal-bed resources, methane gas concentrations in soils and ground water in Carbon and Emery Counties, Utah, were monitored from 1995 to 2003. A total of 420 samples were collected, which contained an average methane concentration of 2,740 parts per million by volume (ppmv) and a median concentration of less than 10 ppmv. On the basis of spatial and temporal methane concentration data collected during the monitoring period, there does not appear to be an obvious, widespread, or consistent migration of methane gas to the near-surface environment.

  15. Monitoring for methane gas in Carbon and Emery Counties, Utah, 1995-2003

    USGS Publications Warehouse

    Burr, Andrew L.; Stolp, Bernard J.; Johnson, Kevin K.; Hunt, Gilbert L.

    2006-01-01

    The release of methane gas from coal beds creates the potential for it to move into near-surface environments through natural and human-made pathways. To help ensure the safety of communities and determine the potential effects of development of coal-bed resources, methane gas concentrations in soils and ground water in Carbon and Emery Counties, Utah, were monitored from 1995 to 2003. A total of 420 samples were collected, which contained an average methane concentration of 2,740 parts per million by volume (ppmv) and a median concentration of less than 10 ppmv. On the basis of spatial and temporal methane concentration data collected during the monitoring period, there does not appear to be an obvious, widespread, or consistent migration of methane gas to the near-surface environment.

  16. Making methane visible

    NASA Astrophysics Data System (ADS)

    Gålfalk, Magnus; Olofsson, Göran; Crill, Patrick; Bastviken, David

    2016-04-01

    Methane (CH4) is one of the most important greenhouse gases, and an important energy carrier in biogas and natural gas. Its large-scale emission patterns have been unpredictable and the source and sink distributions are poorly constrained. Remote assessment of CH4 with high sensitivity at a m2 spatial resolution would allow detailed mapping of the near-ground distribution and anthropogenic sources in landscapes but has hitherto not been possible. Here we show that CH4 gradients can be imaged on the

  17. In situ Investigation of Methane Dry Reforming on M-CeO2(111) {M= Co, Ni, Cu} Surfaces: Metal-Support Interactions and the activation of C-H bonds at Low Temperature

    DOE PAGES

    Rodriguez, Jose A.; Liu, Zongyuan; Lustemberg, Pablo; ...

    2017-08-16

    Studies with a series of M-CeO2(111) {M= Co, Ni, Cu} surfaces indicate that metal-oxide interactions can play a very important role for the activation of methane and its reforming with CO2 at relatively low temperatures (600-700 K). Among the systems examined, Co-CeO2(111) exhibits the best performance and Cu-CeO2(111) has negligible activity. Experiments using ambient pressure XPS indicate that methane dissociates on Co-CeO2(111), at temperatures as low as 300 K, generating CHx and COx species on the catalyst surface. The results of density-functional calculations show a reduction in the methane activation barrier from 1.07 eV on Co(0001) to 0.87 eV onmore » Co2+/CeO2(111), and to only 0.05 eV on Co0/CeO2-x(111). At 700 K, under methane dry reforming conditions, CO2 dissociates on the oxide surface and a catalytic cycle is established without coke deposition. In conclusion, a significant part of the CHx formed on the Co0/CeO2-x (111) catalyst recombines to yield ethane or ethylene.« less

  18. Modeling Modern Methane Emissions from Natural Wetlands. 2; Interannual Variations 1982-1993

    NASA Technical Reports Server (NTRS)

    Walter, Bernadette P.; Heimann, Martin; Mattews, Elaine; Hansen, James E. (Technical Monitor)

    2001-01-01

    A global run of a process-based methane model [Walter et al., this issue] is performed using high-frequency atmospheric forcing fields from ECMWF reanalyses of the period from 1982 to 1993. We calculate global annual methane emissions to be 260 Tg/ yr. 25% of methane emissions originate from wetlands north of 30 deg. N. Only 60% of the produced methane is emitted, while the rest is re-oxidized. A comparison of zonal integrals of simulated global wetland emissions and results obtained by an inverse modeling approach shows good agreement. In a test with data from two wetlands, the seasonality of simulated and observed methane emissions agrees well. The effects of sub-grid scale variations in model parameters and input data are examined. Modeled methane emissions show high regional, seasonal and interannual variability. Seasonal cycles of methane emissions are dominated by temperature in high latitude wetlands, and by changes in the water table in tropical wetlands. Sensitivity tests show that +/- 1 C changes in temperature lead to +/- 20 % changes in methane emissions from wetlands. Uniform changes of +/- 20% in precipitation alter methane emissions by about +/- 18%. Limitations in the model are analyzed. Simulated interannual variations in methane emissions from wetlands are compared to observed atmospheric growth rate anomalies. Our model simulation results suggest that contributions from other sources than wetlands and/or the sinks are more important in the tropics than north-of 30 deg. N. In higher northern latitudes, it seems that a large part, of the observed interannual variations can be explained by variations in wetland emissions. Our results also suggest that reduced wetland emissions played an important role in the observed negative methane growth rate anomaly in 1992.

  19. Methane Emission from Tropical Rivers

    NASA Astrophysics Data System (ADS)

    Sawakuchi, H. O.; Rasera, M. F. F. L.; Krusche, A. V.; Ballester, M. V. R.

    2012-04-01

    Inland water is already known as an important source of methane to atmosphere. Methane is produced in anaerobic environments usually find in lakes and floodplain bottom sediment. It is the main reason that almost all information regarding methane flux come from this environments. However, while floodplain dries during low water season reducing methanogenesis, rivers keep the capacity to emit methane throughout the year. Here we present preliminary results of CH4 flux measurements done in 6 large tropical rivers within the Amazon basin. We measured 17 areas using floating chamber during dry (low water) season, between September and November of 2011, in Amazon river mainstem, Araguaia, Xingu, Tapajós, Madeira, and Negro Rivers. Measured fluxes of all rivers ranged from 59.3 to 2974.4 mmol m-2 yr-1. Geomorphologic structure of channels is one important factor that contributes to this high heterogeneity due to development of low flow velocity depositional settings allowing formation of anoxic zones in rivers. Hydraulic and sediment barriers in the confluence of river channels promote the generation of natural dams which function as a trap for the suspension load favoring the deposition of organic rich muds. This kind of environment is very different from common river channels and has a stronger potential of methane emission. Average values of our flux measurements for this two river environments show that depositional areas can have much higher fluxes than the main channel, 1089.6 and 163.1 mmol m-2 yr-1, respectively. Hence, CH4 flux from these depositional zones is similar to some tropical floodplain lakes and reservoirs. Although the low flux from channel, the area covered by water is very large resulting in a significant contribution to the regional methane emission to the atmosphere. Moreover, mapping the area of these depositional river zones will give us a better idea of the magnitude of methane flux from tropical rivers.

  20. An overview of herb and dietary supplement efficacy, safety and government regulations in the United States with suggested improvements. Part 1 of 5 series.

    PubMed

    Brown, Amy Christine

    2017-09-01

    series to forewarn consumers, clinicians, corporations, and governments of possible serious adverse events. They may also quicken the response rate during Phase IV post-marketing surveillance, in which governments could then exercise their regulatory powers. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Unusually high stable carbon isotopic values of methane from low organic carbon Mars analog hypersaline environments

    NASA Astrophysics Data System (ADS)

    Kelley, C. A.; Poole, J. A.; Tazaz, A.; Chanton, J.; Bebout, B.

    2010-12-01

    Motivated by the Mars rovers’ findings of past hypersaline environments and the discovery of methane in the atmosphere of Mars, we examined methanogenesis in hypersaline ponds in Baja California Sur and in the Don Edwards National Wildlife Refuge in northern California. Methane-rich bubbles were observed to be released from below gypsum/halite crusts in these environments. The stable carbon isotopic composition of these bubbles ranged from about -30 to -40 ‰. Methane with these relatively high isotopic values would typically be considered non-biogenic, however incubations of crust and sediments samples over time resulted in the production of methane. We therefore undertook a series of measurements aimed at understanding the isotopic composition of methane in these environments. The concentrations and isotopic composition of the particulate organic carbon (POC) in these environments were measured. POC content was low (relative to most methane-producing sedimentary environments), generally less than 1%, and always less than 2% of the total mass. The isotopic composition of the POC ranged from -13 to -22 ‰. To determine the substrates used by the methanogens, 13C-labeled trimethylamine (TMA), monomethylamine, methanol, acetate and bicarbonate were added to incubation vials and the methane produced was monitored for 13C content. The main substrates used by the methanogens in these hypersaline environments were the non-competitive substrates, the methylamines and methanol. When unlabeled, but isotopically known, TMA was added to incubation vials in varying concentrations, the isotopic composition of the methane produced also varied. Little, if any, difference in the isotopic composition between the TMA and methane occurred at the lowest TMA concentration (10 µM final concentration). The lowest methane δ13C values (and so greatest fractionation between methane and TMA) occurred when the most TMA was added (1000 µM final concentration). This change in the

  2. Transport of Methane in Trees

    NASA Astrophysics Data System (ADS)

    Kutschera, E.; Khalil, A. K.; Shearer, M. J.; Rosenstiel, T.; Rice, A. L.

    2011-12-01

    Although overall methane (CH4) emissions for croplands, wetlands, and forests have been measured, the exact dynamics of CH4 transport through trees is not well understood. What roles transport mechanisms play in emission rates has been thoroughly investigated for rice, but is fairly unknown for trees. Better defined plant transport mechanisms yield more accurate determination of greenhouse gas flux and its variations, contributing to a comprehensive theory quantifying greenhouse gas emissions globally. CH4 emissions from the common wetland tree species black cottonwood (Populus trichocarpa) native to the Pacific Northwest have been measured under hydroponic conditions in order to separate plant transport processes from the influence of soil processes. Canopy emissions of CH4 have been measured via canopy enclosure. Measurements of CH4 flux from each of 16 trees have indicated that emissions are normally constant over the half-hour sampling period. Samples for stable carbon isotope composition have been taken during these experiments and measured on a mass spectrometer. Compared to the isotopic composition of root water CH4, canopy CH4 is depleted in 13C; this indicates that CH4 moving through the tree is not following a bulk flow pathway (where no depletion would occur), but instead moves either diffusively or through other cell or tissue barriers. No correlation was found to exist between leaf area and CH4 emission; this is vital to upscaling tree-level emissions to the global scale since leaf area index (LAI) cannot be treated as an appropriate parameter to upscale flux. Correctly informing global-scale CH4 fluxes from plants requires an association between the role plant physiology plays in the production and transport of CH4 and magnitudes of flux. This research was supported by the Office of Science (BER), U. S. Department of Energy, Grant No. DE-FG02-08ER64515. Supported in part through NASA / Oregon Space Grant Consortium, grant NNG05GJ85H.

  3. Optimizing immunosuppressive drug dosing in pediatric renal transplantation. Part of a special series on Paediatric Pharmacology, guest edited by Gianvincenzo Zuccotti, Emilio Clementi, and Massimo Molteni.

    PubMed

    Cattaneo, Dario; Vinks, Alexander A

    2012-02-01

    Kidney transplantation in pediatric patients has become a successful and routine procedure, with overall 1-year patient and graft survival rates exceeding 95%. These success rates, however, are not maintained in the long-term, as reported 10-year graft survival rates are in the 50-60% range. Further improvement of long-term allograft survival in pediatric transplantation requires specific focus on long term complications such as increased cardiovascular risk and over-immunosuppression, two linked conditions. One approach to avoid inadequate immunosuppression is to more aggressively tailor immunosuppressive treatment based on individual patient needs. This strategy is currently pursued in the pediatric transplant setting by implementation of individualized therapeutic management of drug concentrations and total exposure. In addition, there is increasing evidence that pharmacogenetic testing may equally benefit individualized immunosuppressive therapy through the identification of SNPs and haplotypes predictive of encoding of proteins involved in drug transport, metabolism and response (efficacy/toxicity). The next challenge will be to provide real time web-based access to all patient information including pharmacokinetic, pharmacodynamic and genotyping data as part of a dosing algorithm or decision support tool with the ultimate goal to adaptively predict and control immunosuppressant exposure and response in individual patients to improve long-term outcomes after kidney transplantation.

  4. High Time Resolution Measurements of Methane Fluxes From Enteric Fermentation in Cattle Rumen

    NASA Astrophysics Data System (ADS)

    Floerchinger, C. R.; Herndon, S.; Fortner, E.; Roscioli, J. R.; Kolb, C. E.; Knighton, W. B.; Molina, L. T.; Zavala, M.; Castelán, O.; Ku Vera, J.; Castillo, E.

    2013-12-01

    Methane accounts for roughly 20% of the global radiative climate forcing in the last two and a half centuries. Methane emissions arise from a number of anthropogenic and biogenic sources. In some areas enteric fermentation in livestock produces over 90% of agricultural methane. In the spring of 2013, as a part of the Short Lived Climate Forcer-Mexico field campaign, the Aerodyne Mobile Laboratory in partnership with the Molina Center for the Environment studied methane production associated with enteric fermentation in the rumen of cattle. A variety of different breeds and stocks being raised in two agricultural and veterinary research facilities located in different areas of Mexico were examined. Methane fluxes were quantified using two methods: 1) an atmospherically stable gaseous tracer release was collocated with small herds in a pasture, allowing tracer ratio flux measurements; 2) respiratory CO2 was measured in tandem with methane in the breath of individual animals allowing methane production to be related to metabolism. The use of an extensive suite of very high time response instruments allows for differentiation of individual methane producing rumination events and respiratory CO2 from possible background interferences. The results of these studies will be presented and compared to data from traditional chamber experiments.

  5. Aerobic and anaerobic methane oxidation in terrestrial mud volcanoes in the Northern Apennines

    NASA Astrophysics Data System (ADS)

    Wrede, C.; Brady, S.; Rockstroh, S.; Dreier, A.; Kokoschka, S.; Heinzelmann, S. M.; Heller, C.; Reitner, J.; Taviani, M.; Daniel, R.; Hoppert, M.

    2012-07-01

    Methane oxidizing prokaryotes are ubiquitous in oxic and anoxic habitats wherever C1-compounds are present. Thus, methane saturated mud volcano fluids should be a preferred habitat of methane consuming prokaryotes, using the readily available electron donors. In order to understand the relevance of methane as a carbon and energy source in mud volcano communities, we investigate the diversity of prokaryotic organisms involved in oxidation of methane in fluid samples from the Salse di Nirano mud volcano field situated in the Northern Apennines. Cell counts were at approximately 0.7 × 106 microbial cells/ml. A fraction of the microbial biomass was identified as ANME (anaerobic methanotroph) archaea by fluorescence in situ hybridization (FISH) analysis. They are associated in densely colonized flakes, of some tens of μm in diameter, embedded in a hyaline matrix. Diversity analysis based on the 16S rDNA genes, retrieved from amplified and cloned environmental DNA, revealed a high proportion of archaea, involved in anaerobic oxidation of methane (AOM). Aerobic methane-oxidizing proteobacteria could be highly enriched from mud volcano fluids, indicating the presence of aerobic methanotrophic bacteria, which may contribute to methane oxidation, whenever oxygen is readily available. The results imply that biofilms, dominated by ANME archaea, colonize parts of the mud volcano venting system.

  6. Iron-mediated anaerobic oxidation of methane in brackish coastal sediments.

    PubMed

    Egger, Matthias; Rasigraf, Olivia; Sapart, Célia J; Jilbert, Tom; Jetten, Mike S M; Röckmann, Thomas; van der Veen, Carina; Bândă, Narcisa; Kartal, Boran; Ettwig, Katharina F; Slomp, Caroline P

    2015-01-06

    Methane is a powerful greenhouse gas and its biological conversion in marine sediments, largely controlled by anaerobic oxidation of methane (AOM), is a crucial part of the global carbon cycle. However, little is known about the role of iron oxides as an oxidant for AOM. Here we provide the first field evidence for iron-dependent AOM in brackish coastal surface sediments and show that methane produced in Bothnian Sea sediments is oxidized in distinct zones of iron- and sulfate-dependent AOM. At our study site, anthropogenic eutrophication over recent decades has led to an upward migration of the sulfate/methane transition zone in the sediment. Abundant iron oxides and high dissolved ferrous iron indicate iron reduction in the methanogenic sediments below the newly established sulfate/methane transition. Laboratory incubation studies of these sediments strongly suggest that the in situ microbial community is capable of linking methane oxidation to iron oxide reduction. Eutrophication of coastal environments may therefore create geochemical conditions favorable for iron-mediated AOM and thus increase the relevance of iron-dependent methane oxidation in the future. Besides its role in mitigating methane emissions, iron-dependent AOM strongly impacts sedimentary iron cycling and related biogeochemical processes through the reduction of large quantities of iron oxides.

  7. Isotopic constraints on sources of methane in Los Angeles, California, USA (Invited)

    NASA Astrophysics Data System (ADS)

    Townsend-Small, A.; Tyler, S. C.; Christensen, L.; Xu, X.; Pataki, D. E.

    2009-12-01

    Methane is a powerful greenhouse gas and an important contributor to global warming. Recent studies have suggested that methane emissions in large cities are underestimated with several models even indicating that substantial emissions attributed to cities are in part from regional and/or encroaching agricultural sources rather than from urban fossil fuel sources. We have found that stable isotopes (13-C and D) and radiocarbon (C-14) are excellent tracers of various sources of methane in Los Angeles, California. Measurements of the d13C and dD of methane from discrete sources show excellent separation between urban sources, such as vehicle emissions, power plants, oil refineries, landfills, and sewage treatment plants and agricultural sources like cows, biogas, and cattle feedlots. In addition, radiocarbon is an excellent tracer of modern versus fossil fuel contributions to methane emissions in the region. Preliminary measurements of background air in Los Angeles indicate that the major source of excess methane is vehicle emissions with most additional CH4 likely contributed from among other fossil fuel sources such as oil refining or power plants. We are currently confirming these results with broader field campaigns and additional measurements, including continuous measurements of atmospheric methane concentration using tunable laser spectroscopy. The combination of high-resolution tunable laser concentration measurements and precise isotope measurements using mass spectrometry is a very promising and powerful tool for methane source monitoring.

  8. Spatio-Temporal Variations in Methane Fluxes in Los Angeles Basin in 2015-2016

    NASA Astrophysics Data System (ADS)

    Yadav, V.; Mueller, K.; Duren, R. M.; Miller, C. E.; Verhulst, K. R.; Nehrkorn, T.

    2016-12-01

    South California air coast basin (SOCAB; i.e. Los Angeles) is an important source of urban Methane emissions in California. Even though annual methane fluxes from SOCAB have been reported earlier, variations in these fluxes at fine spatio-temporal resolution have not been studied. In this research, we utilize a network of in-situ atmospheric measurement sites to investigate weekly variations in methane flux of SOCAB in 2015 and early part of 2016. The sensitivity of the network to identify point sources of methane in the basin is assessed by utilizing Weather Research Forecasting and Stochastic Time Inverted Lagrangian Model. Fluxes of methane, are computed using atmospheric inversions at three km spatial resolution at weekly intervals. The impact of the covariance structure, background estimates of methane, transport model and measurement error, in atmospheric inversions, is assessed within a pseudo data framework. Our findings indicate that atmospheric inversions can identify primary sources of methane emissions during relatively calm atmospheric conditions, fluxes similar to previous studies are only seen during summer months and large variations in methane fluxes are observed at weekly temporal resolution.

  9. Methane clathrate stability zone variations and gas transport in the Martian subsurface

    NASA Astrophysics Data System (ADS)

    Karatekin, O.; Gloesener, E.; Dehant, V. M. A.; Temel, O.

    2016-12-01

    During the last years, several detections of methane in the atmosphere of Mars were reported from Earth-based and Mars orbit instruments with abundances ranging to tens of parts-per-billion by volume (ppbv). Recently, the Curiosity rover detected methane with background levels of 0.7 ppbv and episodic releases of 7 ppbv. Although the methane sources are still unknown, this gas may have been stored in reservoirs of clathrate hydrate in the Martian subsurface where thermodynamics conditions are favourable to their presence. Clathrate hydrates are crystalline compounds constituted by cages formed by hydrogen-bonded water molecules inside of which guest gas molecules are trapped. In this study, methane clathrate stability in the Martian subsurface are investigated and their temporal and spatial variations are studied. Present-day maps of methane clathrate stability zone are produced by coupling the stability conditions of methane clathrate with a subsurface model using the available observations such as the the thermal inertia derived from TES MGS data. Then, a gas transport model has been used to study the methane flux at the surface due to the diffusion of different plausible methane volumes released by clathrate hydrates at variable depths under the Martian surface.

  10. Methane adsorption on the surface of a model of shale: A density functional theory study

    NASA Astrophysics Data System (ADS)

    Zhu, Yuan-qiang; Su, Hong; Jing, Ya; Guo, Jianchun; Tang, Junlei

    2016-11-01

    As a model of shale, one part of polycyclic aromatic ring was used to represent the kerogen surface with the structural heterogeneity. The adsorption mechanisms of methane on the surface of the kerogen were investigated by M06-2× functional with D3 dispersion correction. Nine stable adsorption sites and the orientations of methane (CH4) on the surface of the kerogen were systematically considered. Information from different methods lead to the same conclusion that methane prefers to be adsorbed on the sites directly above the carbon atoms of the kerogen rather than above the center of the six-membered rings. The interactions between methane and the surface of the kerogen are the van der Waals interactions. The interaction energies with the basis set superposition error (BSSE) corrections are around 14 kJ mol-1 at the M06-2×-D3/Jun-cc-pVDZ level. The RDG scatter graphs and the RDG gradient isosurface further illustrate that the interactions between methane and the surface of the kerogen belong to the van der Waals interactions. The weak interactions indicate that the adsorption of methane on the surface of the kerogen is physical adsorption and it slightly depends upon the adsorption sites on kerogen as well as the orientations of methane. These results are helpful for the understanding of the microcosmic mechanism of methane-shale interactions and for the exploitation of shale gas.

  11. Clathrate hydrates as possible source of episodic methane releases on Mars

    NASA Astrophysics Data System (ADS)

    Karatekin, Özgür; Gloesener, Elodie; Temel, Orkun

    2017-04-01

    Methane has been shown to vary with location and time in the Martian atmosphere, with abundances of up to tens of parts-per-billion by volume (ppbv). Since methane is short-lived on geological time scales, its presence implies the existence of an active, current source of methane that is yet to be understood. In this study we investigate the destabilization of subsurface reservoirs of clathrate hydrates as a possible geological source of methane. Clathrate hydrates are crystalline compounds constituted by cages of hydrogen-bonded water molecules, inside of which guest gas molecules are trapped. We show the present-day maps of methane clathrate stability zones, in particular in the vicinity of Gale Crater where the Sample Analysis at Mars (SAM) suite on the Curiosity rover has made in situ measurements of atmospheric methane, during more than 3 years. Curiosity has observed spikes of elevated methane levels of 7 ppbv on four sequential observations over a 2-month period. The possibility of episodic releases consistent with curiosity observations from a subsurface clathrate source, is investigated using a gas transport through porous Martian regolith considering different depths of reservoirs. Transport of the released methane spike into the atmosphere is simulated using the PlanetWRF model.

  12. Internal methane transport through Juncus effusus: experimental manipulation of morphological barriers to test above- and below-ground diffusion limitation.

    PubMed

    Henneberg, Anders; Sorrell, Brian K; Brix, Hans

    2012-11-01

    Aerenchymatous plants can transport methane (CH(4) ) from the root zone to the atmosphere, bypassing the surface-oxidizing layers of the soil, yet morphological and anatomical factors that govern the transport of methane have rarely been critically tested in manipulative experiments. Here, we investigated the methane transport capacity of hydroponically grown Juncus effusus, in experiments with roots submerged in nutrient solutions sparged with methane (1.16 mmol CH(4) l(-1)). Through a range of manipulations of the above- and below-ground plant parts, we tested the contradictory claims in the literature regarding which sites provide the greatest resistance to gas transport. Root manipulations had the greatest effect on methane transport. Removing root material reduced methane transport significantly, and especially the lateral roots and the root tips were important. Cutting of the shoots, with or without subsequent sealing, did not alter methane transport significantly. We confirm modelling predictions that the limiting factor for methane transport in the tussock forming wetland graminoid, J. effusus, is the amount of permeable root surface, estimated using the proxy measurement of root length. The aerial tissues do not provide any significant resistance to methane transport, and the methane is emitted from the lower 50 mm of the shoots.

  13. Revised methane emissions factors and spatially distributed annual carbon fluxes for global livestock.

    PubMed

    Wolf, Julie; Asrar, Ghassem R; West, Tristram O

    2017-09-29

    Livestock play an important role in carbon cycling through consumption of biomass and emissions of methane. Recent research suggests that existing bottom-up inventories of livestock methane emissions in the US, such as those made using 2006 IPCC Tier 1 livestock emissions factors, are too low. This may be due to outdated information used to develop these emissions factors. In this study, we update information for cattle and swine by region, based on reported recent changes in animal body mass, feed quality and quantity, milk productivity, and management of animals and manure. We then use this updated information to calculate new livestock methane emissions factors for enteric fermentation in cattle, and for manure management in cattle and swine. Using the new emissions factors, we estimate global livestock emissions of 119.1 ± 18.2 Tg methane in 2011; this quantity is 11% greater than that obtained using the IPCC 2006 emissions factors, encompassing an 8.4% increase in enteric fermentation methane, a 36.7% increase in manure management methane, and notable variability among regions and sources. For example, revised manure management methane emissions for 2011 in the US increased by 71.8%. For years through 2013, we present (a) annual livestock methane emissions, (b) complete annual livestock carbon budgets, including carbon dioxide emissions, and (c) spatial distributions of livestock methane and other carbon fluxes, downscaled to 0.05 × 0.05 degree resolution. Our revised bottom-up estimates of global livestock methane emissions are comparable to recently reported top-down global estimates for recent years, and account for a significant part of the increase in annual methane emissions since 2007. Our results suggest that livestock methane emissions, while not the dominant overall source of global methane emissions, may be a major contributor to the observed annual emissions increases over the 2000s to 2010s. Differences at regional and local scales may help

  14. Rhythms of Methane Emission: Long-term Observations on Mud-volcano Eruptions

    NASA Astrophysics Data System (ADS)

    de Beer, D.; Boetius, A.; German, C. R.; Olu, K.; Feseker, T.

    2016-02-01

    Submarine mud volcanoes are important sources of methane to the water column. It has been estimated that the submarine volcanos emit 27 Million tons of methane, which is about 5% of the global emission. However, these numbers are uncertain as the temporal variability of their mud and methane emissions is unknown. Methane emissions were previously proposed to result from a dynamic equilibrium between upward migration and consumption at the seabed by methane-consuming microbes. Here we show non-steady state situations of vigorous mud movement that are revealed through variations in fluid flow, seabed temperature and seafloor bathymetry. Time series data for pressure, temperature, pH and seafloor photography were collected over 431 days using a benthic observatory at the active Håkon Mosby Mud Volcano. We documented 25 pulses of hot subsurface fluids, accompanied by eruptions that changed the landscape of the mud volcano. Four major events triggered rapid sediment uplift of more than a meter in height, substantial lateral flow of muds at average velocities of 0.4 m day-1, and significant emissions of methane and CO2 from the seafloor. We calculated that to drive these eruptions at least 10 times more gas is emitted that previously assumed. The contribution of submarine mud volcanoes to the global methane budget may thus strongly underestimated.

  15. The Potential for Methane Isotopologue Channels in GOSAT-2

    NASA Astrophysics Data System (ADS)

    Malina, Edward; Yoshida, Yukio; Matsunaga, Tsuneo; Muller, Jan-Peter

    2017-04-01

    ) appropriate for isotopologues have been defined previously, we therefore test a number VCMs in order to explore the constraints on retrieving independent information in the total column based on the IC analysis. This analysis and VCM variations also provide the opportunity to explore the potential errors associated with retrievals of isotopologues. Based on this study we will comment on the feasibility of Methane isotopologues retrieval with GOSAT-2 under a range of atmospheric conditions, instrument geometry and VCM setups, as well as the errors associated with these conditions. References: Etiope, G. (2009) 'Natural emissions of methane from geological seepage in Europe', Atmospheric Environment, 43(7), pp. 1430-1443. doi: 10.1016/j.atmosenv.2008.03.014. Heimann, M. (2011) 'Atmospheric science: Enigma of the recent methane budget', Nature, 476(7359), pp. 157-158. doi: 10.1038/476157a. IPCC. Climate Change 2014: Impacts, Adaptation, and Vulnerability. Part A: Global and Sectoral Aspects. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Available online: https://ipcc-wg2.gov/AR5/report/ Rodgers, C.D. (2000) Inverse methods for atmospheric sounding: Theory and practice. Singapore, Singapore: World Scientific Publishing Company.

  16. A large increase in U.S. methane emissions over the past decade inferred from satellite data and surface observations

    NASA Astrophysics Data System (ADS)

    Turner, A. J.; Jacob, D. J.; Benmergui, J.; Wofsy, S. C.; Maasakkers, J. D.; Butz, A.; Hasekamp, O.; Biraud, S. C.

    2016-03-01

    The global burden of atmospheric methane has been increasing over the past decade, but the causes are not well understood. National inventory estimates from the U.S. Environmental Protection Agency indicate no significant trend in U.S. anthropogenic methane emissions from 2002 to present. Here we use satellite retrievals and surface observations of atmospheric methane to suggest that U.S. methane emissions have increased by more than 30% over the 2002-2014 period. The trend is largest in the central part of the country, but we cannot readily attribute it to any specific source type. This large increase in U.S. methane emissions could account for 30-60% of the global growth of atmospheric methane seen in the past decade.

  17. River methane hot-spots: Continuous methane ebullition measurements over an annual cycle linked to river sediment production

    NASA Astrophysics Data System (ADS)

    Wilkinson, Jeremy; Maeck, Andreas; Ashboul, Zeyad; Lorke, Andreas

    2015-04-01

    Hot spot methane ebullition from impounded river reaches matches high rates observed around the globe. Ebullition dominates total methane flux in the Saar River (Germany) and is largely determined by sediment deposition rate. Using automated bubble traps developed in-house, and deployed over a year at four sites, we collected high resolution data showing that hydrodynamic disturbances from shipping, lock operations and hydrograph events trigger ebullition episodes. Reverse smoothing was used to integrate the observed ebullition back in time, and helped in visualizing the data, and provides a time-series closer to methane accumulation in the sediments, whereas ebullition shows the triggering and release of the accumulated gas. One major hydrological disturbance of shallow-water sediment released around 13% of the total annual ebullition at that site, and ebullition generally followed the seasonal sediment temperature variations. The same event damped ebullition from deeper water sites. Total annual ebullition values ranged from 200 to 500 gCH4 m-2 yr-1. Ebullition from shallow water sediments in winter ceased for extended periods, but continued un-broken from deeper sites. With on-going measurements we believe these findings will help to improve estimates and the modelling of methane emissions from impounded river systems.

  18. Evaluation of Biogeochemical Processes and Rock-Water Interactions in the Black Warrior Basin Coalbed Methane Reservoir (Alabama, USA) Via Isotopic Characterization of Formation Water Samples

    NASA Astrophysics Data System (ADS)

    Quan, T. M.; Vinson, D. S.; Prock, A.; Darrah, T.; McIntyre-Redden, M. R.; Pashin, J. C.

    2016-12-01

    Isotopic analysis of formation waters from coalbed methane reservoirs can provide critical information regarding carbon cycling, methanogenesis, generation and biodegradation of organic compounds, and rock-water interactions. As part of a larger study characterizing the biogeochemical processes within the Black Warrior Basin coalbed methane reservoir (Alabama, USA), a series of isotopic analyses were performed on formation water samples collected in the summer of 2015, including δ13CDIC, δDH2O, δ18OH2O, and δ13CDOC. High measured δ13CDIC values indicate predominant microbial methane generation, which is supported by δ13CCH4 values. Preliminary sample values for δ18OH2O and δDH2O do not correlate with salinity or dissolved inorganic carbon concentrations, which suggests interesting implications for recharge patterns and potential rock-water interactions. Preliminary δ13CDOC data suggests that dissolved organic carbon in these samples has a biogenic, not a thermogenic source. Accordingly, our data indicates that methanogenic microbes appear to have utilized more labile biogenic organic compounds in formation water rather than the highly polymerized vitreous carbon from host coal seams.

  19. Measurements of the methane relaxation times for application to the infrared emission models of the upper atmospheres of outer planets and Titan

    NASA Technical Reports Server (NTRS)

    Halthore, Rangasayi N.; Caldwell, John J.; Allen, John E., Jr.; Burt, Jim A.; Yang, Kuanghua; Delaney, Paul

    1990-01-01

    The 7.8 micrometer emission from the nu(sub 4) band of methane (CH4) is a regularly observed feature in the stratosphere of all the giant planets and Titan. On Jupiter, enhancements in this emission are associated with the infrared hot spots in the auroral zone. Attempts to model this phenomenon in particular, and to understand the role of methane in general, have been hampered in part by a lack of adequate laboratory measurements of the collisional relaxation times for the nu(sub 3) and nu(sub 4) levels over the appropriate temperature range. To provide this needed data, a series of laboratory experiments were initiated. In the experimental arrangement the nu(sub3) band of methane is pumped at 3.3 micrometers using a pulsed infrared source (Nd:YAG/dye laser system equipped with a wave-length extender). The radiative lifetime of the nu(sub 3) level (approximately 37 ms) is much shorter than the nu(sub 4) lifetime (approximately 390 ms); however, a rapid V-V energy transfer rate ensures that the nu(sub 4) level is substantially populated. The photoacoustic technique is used to acquire relaxation rate information. The experiments are performed using a low-temperature, low-pressure cell. Experimental apparatus and technique are described. In addition some of the experimental difficulties associated with making these measurements are discussed and some preliminary results are presented.

  20. Effects of the methane-inhibitors nitrate, nitroethane, lauric acid, Lauricidin**R and the Hawaiian marine algae, Chaetoceros, on ruminal fermentation in vitro

    USDA-ARS?s Scientific Manuscript database

    The effects of several methane-inhibitors on rumen fermentation were compared during three 24 h consecutive batch cultures of ruminal microbes in the presence of nonlimiting amounts of hydrogen. After the initial incubation series, methane production was reduced greater than 92% from that of nontre...