Sample records for control nitrogen oxide

  1. 40 CFR 52.278 - Oxides of nitrogen control.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Oxides of nitrogen control. 52.278... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.278 Oxides of nitrogen control. (a) The following regulations are disapproved because they relax the control of nitrogen oxides...

  2. 40 CFR 52.278 - Oxides of nitrogen control.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 3 2012-07-01 2012-07-01 false Oxides of nitrogen control. 52.278... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.278 Oxides of nitrogen control. (a) The following regulations are disapproved because they relax the control of nitrogen oxides...

  3. 40 CFR 52.278 - Oxides of nitrogen control.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Oxides of nitrogen control. 52.278... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.278 Oxides of nitrogen control. (a) The following regulations are disapproved because they relax the control of nitrogen oxides...

  4. 40 CFR 52.278 - Oxides of nitrogen control.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Oxides of nitrogen control. 52.278... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.278 Oxides of nitrogen control. (a) The following regulations are disapproved because they relax the control of nitrogen oxides...

  5. 40 CFR Appendix B to Part 76 - Procedures and Methods for Estimating Costs of Nitrogen Oxides Controls Applied to Group 1, Boilers

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Costs of Nitrogen Oxides Controls Applied to Group 1, Boilers B Appendix B to Part 76 Protection of... of Nitrogen Oxides Controls Applied to Group 1, Boilers 1. Purpose and Applicability This technical...; and which is comparable to the costs of nitrogen oxides controls set pursuant to subsection (b)(1) (of...

  6. 40 CFR Appendix B to Part 76 - Procedures and Methods for Estimating Costs of Nitrogen Oxides Controls Applied to Group 1, Boilers

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Costs of Nitrogen Oxides Controls Applied to Group 1, Boilers B Appendix B to Part 76 Protection of... of Nitrogen Oxides Controls Applied to Group 1, Boilers 1. Purpose and Applicability This technical...; and which is comparable to the costs of nitrogen oxides controls set pursuant to subsection (b)(1) (of...

  7. 40 CFR Appendix B to Part 76 - Procedures and Methods for Estimating Costs of Nitrogen Oxides Controls Applied to Group 1, Boilers

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Costs of Nitrogen Oxides Controls Applied to Group 1, Boilers B Appendix B to Part 76 Protection of... of Nitrogen Oxides Controls Applied to Group 1, Boilers 1. Purpose and Applicability This technical...; and which is comparable to the costs of nitrogen oxides controls set pursuant to subsection (b)(1) (of...

  8. 40 CFR Appendix B to Part 76 - Procedures and Methods for Estimating Costs of Nitrogen Oxides Controls Applied to Group 1, Boilers

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Costs of Nitrogen Oxides Controls Applied to Group 1, Boilers B Appendix B to Part 76 Protection of... of Nitrogen Oxides Controls Applied to Group 1, Boilers 1. Purpose and Applicability This technical...; and which is comparable to the costs of nitrogen oxides controls set pursuant to subsection (b)(1) (of...

  9. 40 CFR Appendix B to Part 76 - Procedures and Methods for Estimating Costs of Nitrogen Oxides Controls Applied to Group 1, Boilers

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Costs of Nitrogen Oxides Controls Applied to Group 1, Boilers B Appendix B to Part 76 Protection of... of Nitrogen Oxides Controls Applied to Group 1, Boilers 1. Purpose and Applicability This technical...; and which is comparable to the costs of nitrogen oxides controls set pursuant to subsection (b)(1) (of...

  10. 40 CFR 52.278 - Oxides of nitrogen control.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Oxides of nitrogen control. 52.278 Section 52.278 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.278 Oxides of nitrogen control...

  11. 40 CFR 52.1876 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 4 2013-07-01 2013-07-01 false Control strategy: Nitrogen dioxide. 52...: Nitrogen dioxide. (a) The condition to EPA's approval of the oxides of nitrogen State Implementation Plan... change to the flow control date in the oxides of nitrogen budget trading SIP. (b) [Reserved] [69 FR 13234...

  12. 40 CFR 52.1876 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 4 2014-07-01 2014-07-01 false Control strategy: Nitrogen dioxide. 52...: Nitrogen dioxide. (a) The condition to EPA's approval of the oxides of nitrogen State Implementation Plan... change to the flow control date in the oxides of nitrogen budget trading SIP. (b) [Reserved] [69 FR 13234...

  13. 40 CFR 52.1876 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Control strategy: Nitrogen dioxide. 52...: Nitrogen dioxide. (a) The condition to EPA's approval of the oxides of nitrogen State Implementation Plan... change to the flow control date in the oxides of nitrogen budget trading SIP. (b) [Reserved] [69 FR 13234...

  14. 40 CFR 52.1876 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 4 2012-07-01 2012-07-01 false Control strategy: Nitrogen dioxide. 52...: Nitrogen dioxide. (a) The condition to EPA's approval of the oxides of nitrogen State Implementation Plan... change to the flow control date in the oxides of nitrogen budget trading SIP. (b) [Reserved] [69 FR 13234...

  15. 40 CFR 52.1876 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...: Nitrogen dioxide. (a) The condition to EPA's approval of the oxides of nitrogen State Implementation Plan... change to the flow control date in the oxides of nitrogen budget trading SIP. (b) [Reserved] [69 FR 13234...

  16. 40 CFR 52.65 - Control Strategy: Nitrogen oxides.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Control Strategy: Nitrogen oxides. 52... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Alabama § 52.65 Control Strategy: Nitrogen... using to implement provisions of the Prevention of Significant Deterioration regulations for nitrogen...

  17. 40 CFR 52.65 - Control Strategy: Nitrogen oxides.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 3 2012-07-01 2012-07-01 false Control Strategy: Nitrogen oxides. 52... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Alabama § 52.65 Control Strategy: Nitrogen... using to implement provisions of the Prevention of Significant Deterioration regulations for nitrogen...

  18. 40 CFR 52.65 - Control Strategy: Nitrogen oxides.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Control Strategy: Nitrogen oxides. 52... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Alabama § 52.65 Control Strategy: Nitrogen... using to implement provisions of the Prevention of Significant Deterioration regulations for nitrogen...

  19. 40 CFR 52.65 - Control Strategy: Nitrogen oxides.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Control Strategy: Nitrogen oxides. 52... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Alabama § 52.65 Control Strategy: Nitrogen... using to implement provisions of the Prevention of Significant Deterioration regulations for nitrogen...

  20. Nox control for high nitric oxide concentration flows through combustion-driven reduction

    DOEpatents

    Yeh, James T.; Ekmann, James M.; Pennline, Henry W.; Drummond, Charles J.

    1989-01-01

    An improved method for removing nitrogen oxides from concentrated waste gas streams, in which nitrogen oxides are ignited with a carbonaceous material in the presence of substoichiometric quantities of a primary oxidant, such as air. Additionally, reductants may be ignited along with the nitrogen oxides, carbonaceous material and primary oxidant to achieve greater reduction of nitrogen oxides. A scrubber and regeneration system may also be included to generate a concentrated stream of nitrogen oxides from flue gases for reduction using this method.

  1. Interactions between nitrogen cycling and methane oxidation in the pelagic waters of the Gulf of Mexico.

    NASA Astrophysics Data System (ADS)

    Joye, S. B.; Weber, S.; Battles, J.; Montoya, J. P.

    2014-12-01

    Methane is an important greenhouse gas that plays a critical role in climate variation. Although a variety of marine methane sources and sinks have been identified, key aspects of the fate of methane in the ocean remain poorly constrained. At cold seeps in the Gulf of Mexico and elsewhere, methane is introduced into the overlying water column via fluid escape from the seabed. We quantified the fate of methane in the water column overlying seafloor cold seeps, in a brine basin, and at several control sites. Our goals were to determine the factors that regulated methane consumption and assimilation and to explore how these controlling factors varied among and between sites. In particular, we examined the impact of nitrogen availability on methane oxidation and studied the ability of methane oxidizing bacteria to fix molecular nitrogen. Methane oxidation rates were highest in the methane rich bottom waters of natural hydrocabron seeps. At these sites, inorganic nitrogen addition stimulated methane oxidation in laboratory experiments. In vitro shipboard experiments revealed that rates of methane oxidation and nitrogen fixation were correlated strongly, suggesting that nitrogen fixation may have been mediated by methanotrophic bacteria. The highest rates of methane oxidation and nitrogen fixation were observed in the deepwater above at natural hydrocarbon seeps. Rates of methane oxidation were substantial along the chemocline of a brine basin but in these ammonium-rich brines, addition of inorganic nitrogen had little impact on methane oxidation suggesting that methanotrophy in these waters were not nitrogen limited. Control sites exhibited the lowest methane concentrations and methane oxidation rates but even these waters exhibited substantial potential for methane oxidation when methane and inorganic nitrogen concentrations were increased. Together, these data suggest that the availability of inorganic nitrogen plays a critical role in regulating methane oxidation in pelagic ocean waters. Some methanotrophs may obtain a competitive advantage in nitrogen-limited oceanic environments by fixing molecular nitrogen. The importance of such "methano-diazotrophy" on a global scale warrants further investigation.

  2. 40 CFR 52.65 - Control Strategy: Nitrogen oxides.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control Strategy: Nitrogen oxides. 52.65 Section 52.65 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Alabama § 52.65 Control Strategy: Nitrogen...

  3. 40 CFR 52.770 - Identification of plan.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 11/30/2004, 69 FR 69531. Article 10. Nitrogen Oxides Rules 10-1 Nitrogen Oxides Control in Clark and Floyd Counties 6/12/1996 6/3/1997, 62 FR 30253. 10-3 Nitrogen Oxide Reduction Program for Specific Source Categories 02/25/2007 11/29/2010, 75 FR 72956 Sec. 1. 10-4 Nitrogen Oxides Budget Trading Program...

  4. 75 FR 31711 - Approval and Promulgation of Air Quality Implementation Plans; Delaware; Control of Nitrogen...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-04

    ... Boilers and Process Heaters at Petroleum Refineries AGENCY: Environmental Protection Agency (EPA). ACTION... controlling nitrogen oxide (NOx) emissions from industrial boilers. This action is being taken under the Clean...--Control of Nitrogen Oxide Emissions from Industrial Boilers and Process Heaters at Petroleum Refineries in...

  5. Controls for maintaining low nitrogen oxides content in internal combustion engine exhaust gases

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Siebke, H.; Moro, B.; Schoenborn, M.

    1976-08-10

    A control system and apparatus for measuring and monitoring the nitrogen oxides content of internal combustion engine exhaust gases is described. The exhaust gases are contacted with the reducing electrode of a sensor cell having a predetermined potential established between the cell electrodes so that the reducing electrode is able to reduce both the nitrogen oxides and oxygen content of the exhaust gas. The current flowing through the sensor cell is measured to determine whether the nitrogen oxides content of the exhaust gas is sufficiently low.

  6. 76 FR 34021 - Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Control of Nitrogen...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-10

    ... Promulgation of Air Quality Implementation Plans; Pennsylvania; Control of Nitrogen Oxides Emissions From Glass... Pennsylvania. This revision pertains to the control of nitrogen oxide (NO X ) emissions from glass melting... Plan for the control of NO X from glass melting furnaces. I. Background The SIP revision consists of a...

  7. 76 FR 52283 - Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Control of Nitrogen...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-22

    ... Promulgation of Air Quality Implementation Plans; Pennsylvania; Control of Nitrogen Oxides Emissions From Glass... revisions pertain to the control of nitrogen oxide (NO X ) emissions from glass melting furnaces. EPA is approving these revisions to reduce NO X emissions from glass melting furnaces in accordance with the...

  8. 40 CFR 52.235 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Control strategy for ozone: Oxides of... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the Monterey Bay Unified Air Pollution Control District on April 26, 1994 for the Monterey Bay ozone nonattainment area...

  9. 40 CFR 52.235 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Control strategy for ozone: Oxides of... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the Monterey Bay Unified Air Pollution Control District on April 26, 1994 for the Monterey Bay ozone nonattainment area...

  10. 40 CFR 52.235 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Control strategy for ozone: Oxides of... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the Monterey Bay Unified Air Pollution Control District on April 26, 1994 for the Monterey Bay ozone nonattainment area...

  11. 40 CFR 52.235 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy for ozone: Oxides of... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the Monterey Bay Unified Air Pollution Control District on April 26, 1994 for the Monterey Bay ozone nonattainment area...

  12. 40 CFR 52.235 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 3 2012-07-01 2012-07-01 false Control strategy for ozone: Oxides of... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the Monterey Bay Unified Air Pollution Control District on April 26, 1994 for the Monterey Bay ozone nonattainment area...

  13. 78 FR 46552 - Approval and Promulgation of Air Quality Implementation Plans; Massachusetts; Regulations...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-01

    ... Volatile Organic Compounds and Nitrogen Oxides AGENCY: Environmental Protection Agency (EPA). ACTION... requirements for stationary sources of volatile organic compounds (VOCs) and nitrogen oxides (NO X ). This... to 310 CMR 7.19, Reasonably Available Control Technology (RACT) for Sources of Oxides of Nitrogen (NO...

  14. 40 CFR 52.136 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 3 2012-07-01 2012-07-01 false Control strategy for ozone: Oxides of... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the State of Arizona on April 13, 1994 for the Maricopa County ozone nonattainment area from the NOX RACT requirements...

  15. 40 CFR 52.136 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy for ozone: Oxides of... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the State of Arizona on April 13, 1994 for the Maricopa County ozone nonattainment area from the NOX RACT requirements...

  16. 40 CFR 52.136 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Control strategy for ozone: Oxides of... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the State of Arizona on April 13, 1994 for the Maricopa County ozone nonattainment area from the NOX RACT requirements...

  17. 40 CFR 52.136 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Control strategy for ozone: Oxides of... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the State of Arizona on April 13, 1994 for the Maricopa County ozone nonattainment area from the NOX RACT requirements...

  18. 40 CFR 52.136 - Control strategy for ozone: Oxides of nitrogen.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Control strategy for ozone: Oxides of... for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the State of Arizona on April 13, 1994 for the Maricopa County ozone nonattainment area from the NOX RACT requirements...

  19. 40 CFR 62.9350 - Identification of plan.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... plan was officially submitted as follows: (1) Control of fluoride emissions from phosphate fertilizer... August 9, 1982. (4) Control of metals, acid gases, organic compounds and nitrogen oxide emissions from..., organic compounds, particulates and nitrogen oxide emissions from existing Hospital/Medical/Infectious...

  20. 78 FR 49701 - Approval and Promulgation of Implementation Plans; Connecticut; Control of Visible Emissions...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-15

    ... power plants and other large stationary sources of air pollution''), 22a-174-22 (``Control of Nitrogen Oxide Emissions''), and 22a-174-22c (``The Clean Air Interstate Rule (CAIR) Nitrogen Oxides (NO X...

  1. 40 CFR 52.770 - Identification of plan.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    .../1980 11/5/1981, 46 FR 54943. 1-2-88 “Vapor balance system″ defined 9/26/1980 11/5/1981, 46 FR 54943. 1... Specific testing procedures; particulate matter; PM10; PM2.5; sulfur dioxide; nitrogen oxides; volatile.../2002 11/30/2004, 69 FR 69531. Article 10. Nitrogen Oxides Rules 10-1 Nitrogen Oxides Control in Clark...

  2. A case study of the relative effects of power plant nitrogen oxides and sulfur dioxide emission reductions on atmospheric nitrogen deposition.

    PubMed

    Vijayaraghavan, Krish; Seigneur, Christian; Bronson, Rochelle; Chen, Shu-Yun; Karamchandani, Prakash; Walters, Justin T; Jansen, John J; Brandmeyer, Jo Ellen; Knipping, Eladio M

    2010-03-01

    The contrasting effects of point source nitrogen oxides (NOx) and sulfur dioxide (SO2) air emission reductions on regional atmospheric nitrogen deposition are analyzed for the case study of a coal-fired power plant in the southeastern United States. The effect of potential emission reductions at the plant on nitrogen deposition to Escambia Bay and its watershed on the Florida-Alabama border is simulated using the three-dimensional Eulerian Community Multiscale Air Quality (CMAQ) model. A method to quantify the relative and individual effects of NOx versus SO2 controls on nitrogen deposition using air quality modeling results obtained from the simultaneous application of NOx and SO2 emission controls is presented and discussed using the results from CMAQ simulations conducted with NOx-only and SO2-only emission reductions; the method applies only to cases in which ambient inorganic nitrate is present mostly in the gas phase; that is, in the form of gaseous nitric acid (HNO3). In such instances, the individual effects of NOx and SO2 controls on nitrogen deposition can be approximated by the effects of combined NOx + SO2 controls on the deposition of NOy, (the sum of oxidized nitrogen species) and reduced nitrogen species (NHx), respectively. The benefit of controls at the plant in terms of the decrease in nitrogen deposition to Escambia Bay and watershed is less than 6% of the overall benefit due to regional Clean Air Interstate Rule (CAIR) controls.

  3. Rapid cycling of reactive nitrogen in the marine boundary layer.

    PubMed

    Ye, Chunxiang; Zhou, Xianliang; Pu, Dennis; Stutz, Jochen; Festa, James; Spolaor, Max; Tsai, Catalina; Cantrell, Christopher; Mauldin, Roy L; Campos, Teresa; Weinheimer, Andrew; Hornbrook, Rebecca S; Apel, Eric C; Guenther, Alex; Kaser, Lisa; Yuan, Bin; Karl, Thomas; Haggerty, Julie; Hall, Samuel; Ullmann, Kirk; Smith, James N; Ortega, John; Knote, Christoph

    2016-04-28

    Nitrogen oxides are essential for the formation of secondary atmospheric aerosols and of atmospheric oxidants such as ozone and the hydroxyl radical, which controls the self-cleansing capacity of the atmosphere. Nitric acid, a major oxidation product of nitrogen oxides, has traditionally been considered to be a permanent sink of nitrogen oxides. However, model studies predict higher ratios of nitric acid to nitrogen oxides in the troposphere than are observed. A 'renoxification' process that recycles nitric acid into nitrogen oxides has been proposed to reconcile observations with model studies, but the mechanisms responsible for this process remain uncertain. Here we present data from an aircraft measurement campaign over the North Atlantic Ocean and find evidence for rapid recycling of nitric acid to nitrous acid and nitrogen oxides in the clean marine boundary layer via particulate nitrate photolysis. Laboratory experiments further demonstrate the photolysis of particulate nitrate collected on filters at a rate more than two orders of magnitude greater than that of gaseous nitric acid, with nitrous acid as the main product. Box model calculations based on the Master Chemical Mechanism suggest that particulate nitrate photolysis mainly sustains the observed levels of nitrous acid and nitrogen oxides at midday under typical marine boundary layer conditions. Given that oceans account for more than 70 per cent of Earth's surface, we propose that particulate nitrate photolysis could be a substantial tropospheric nitrogen oxide source. Recycling of nitrogen oxides in remote oceanic regions with minimal direct nitrogen oxide emissions could increase the formation of tropospheric oxidants and secondary atmospheric aerosols on a global scale.

  4. 75 FR 48566 - Approval and Promulgation of Air Quality Implementation Plans; Delaware; Administrative and Non...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-11

    ...''; Regulation 12 ``Control of Nitrogen Oxide Emissions''; Regulation 1113* ``Open Burning''; Regulation 14... of General Federal Actions to the State Implementation Plans''; Regulation 39 ``Nitrogen Oxides (NO X..., Intergovernmental relations, Nitrogen dioxide, Ozone, Particulate matter, Reporting and recordkeeping requirements...

  5. TECHNOLOGY INNOVATIONS AND EXPERIENCE CURVES FOR NITROGEN OXIDES CONTROL TECHNOLOGIES

    EPA Science Inventory

    This paper reviews the regulatory history for nitrogen oxides (NOX) pollutant emissions from stationary sources, primarily in coal-fired power plants. Nitrogen dioxide (NO2) is one of the six criteria pollutants regulated by the 1970 Clean Air Act where Nati...

  6. COMBUSTION MODIFICATION CONTROL OF NITROGEN OXIDES (EPA/600/F-95/012)

    EPA Science Inventory

    EPA's efforts in research and development of nitrogen oxide (NOx) control technologies by
    means of modifying the combustion process have played a major role in reducing stationary
    source NOx emissions by over 3 million tons (2.73 x 10^6 tonnes) annually, and have led to at<...

  7. 75 FR 64951 - Approval and Promulgation of Implementation Plans; Illinois; Voluntary Nitrogen Oxides Controls

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-21

    ... for regulations governing Nitrogen Oxides (NO X ) emission allowances granted for implementation of voluntary control of NO X emissions from sources other than those covered by other Illinois NO X emission..., which would have incorporated a rule governing NO X emission allowances (estimation and crediting of NO...

  8. 40 CFR 52.1781 - Control strategy: Sulfur oxides and particulate matter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 4 2013-07-01 2013-07-01 false Control strategy: Sulfur oxides and... Carolina § 52.1781 Control strategy: Sulfur oxides and particulate matter. (a) The plan's control strategy... State expects the resulting emission reductions of nitrogen oxides and sulfur dioxide from this control...

  9. 40 CFR 52.1781 - Control strategy: Sulfur oxides and particulate matter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 4 2014-07-01 2014-07-01 false Control strategy: Sulfur oxides and... Carolina § 52.1781 Control strategy: Sulfur oxides and particulate matter. (a) The plan's control strategy... State expects the resulting emission reductions of nitrogen oxides and sulfur dioxide from this control...

  10. 40 CFR 52.1781 - Control strategy: Sulfur oxides and particulate matter.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 4 2012-07-01 2012-07-01 false Control strategy: Sulfur oxides and... Carolina § 52.1781 Control strategy: Sulfur oxides and particulate matter. (a) The plan's control strategy... State expects the resulting emission reductions of nitrogen oxides and sulfur dioxide from this control...

  11. 75 FR 14116 - Approval of Implementation Plans of Wisconsin: Nitrogen Oxides Reasonably Available Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-24

    ... Annealing Furnace. Asphalt Plants =>65 mmBtu/hr... Gaseous fuel, 0.15 lbs/mmBtu. Distillate oil, 0.20 lbs/mm... relations, Nitrogen oxides, Ozone, Particulate matter, Reporting and recordkeeping requirements, Sulfur...

  12. Analysis of alternative pathways for reducing nitrogen oxide emissions

    EPA Science Inventory

    Strategies for reducing tropospheric ozone typically include modifying combustion processes to reduce the formation of nitrogen oxides (NOx) and applying control devices that remove NOx from the exhaust gases of power plants, industrial sources and vehicles. For portions of the ...

  13. 40 CFR 52.1676 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 4 2012-07-01 2012-07-01 false Control strategy: Nitrogen dioxide. 52...: Nitrogen dioxide. (a) The requirements of § 52.14(c)(3) of this chapter as of May 8, 1974 (39 FR 16347), are not met since the plans do not provide for the degree of nitrogen oxides emission reduction...

  14. 40 CFR 52.1676 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 4 2013-07-01 2013-07-01 false Control strategy: Nitrogen dioxide. 52...: Nitrogen dioxide. (a) The requirements of § 52.14(c)(3) of this chapter as of May 8, 1974 (39 FR 16347), are not met since the plans do not provide for the degree of nitrogen oxides emission reduction...

  15. 40 CFR 52.1676 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 4 2014-07-01 2014-07-01 false Control strategy: Nitrogen dioxide. 52...: Nitrogen dioxide. (a) The requirements of § 52.14(c)(3) of this chapter as of May 8, 1974 (39 FR 16347), are not met since the plans do not provide for the degree of nitrogen oxides emission reduction...

  16. 40 CFR 52.1676 - Control strategy: Nitrogen dioxide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Control strategy: Nitrogen dioxide. 52...: Nitrogen dioxide. (a) The requirements of § 52.14(c)(3) of this chapter as of May 8, 1974 (39 FR 16347), are not met since the plans do not provide for the degree of nitrogen oxides emission reduction...

  17. CONTROLLING NITROGEN OXIDES

    EPA Science Inventory

    Recent research indicates that nitrogen oxides (NOx) could be one of the most troublesome air pollutants of the 1980's. More than 20 million metric tons of NOx are annually polluting our air as a result of the widespread combustion of fossil fuels in power plants, industrial boil...

  18. Flume experiments elucidate relationships between microbial genetics, nitrogen species and hydraulics in controlling nitrous oxide production in the hyporheic zone

    NASA Astrophysics Data System (ADS)

    Quick, A. M.; Farrell, T. B.; Reeder, W. J.; Feris, K. P.; Tonina, D.; Benner, S. G.

    2014-12-01

    The hyporheic zone is a potentially important producer of nitrous oxide, a powerful greenhouse gas. The location and magnitude of nitrous oxide generation within the hyporheic zone involves complex interactions between multiple nitrogen species, redox conditions, microbial communities, and hydraulics. To better understand nitrous oxide generation and emissions from streams, we conducted large-scale flume experiments in which we monitored pore waters along hyporheic flow paths within stream dune structures. Measured dissolved oxygen, ammonia, nitrate, nitrite, and dissolved nitrous oxide showed distinct spatial relationships reflecting redox changes along flow paths. Denitrifying genes (nosZ, nirS, and nirK), determined using qPCR, were spatially associated with abundances of nitrogen species. Using residence times along a flow path, clear trends in oxygen conditions, genes encoding for microbial catalysis, and nitrogen species were observed. Hotspots of targeted genes correlated with hotspots for conversion of nitrogen species, including nitrous oxide production and conversion to dinitrogen. Trends were apparent regardless of dune size, allowing for the possibility to apply observed relationships to multiple streambed morphologies. Relating streambed morphology and loading of nitrogen species allows for prediction of nitrous oxide production in the hyporheic zone.

  19. Community Composition of Nitrous Oxide-Related Genes in Salt Marsh Sediments Exposed to Nitrogen Enrichment.

    PubMed

    Angell, John H; Peng, Xuefeng; Ji, Qixing; Craick, Ian; Jayakumar, Amal; Kearns, Patrick J; Ward, Bess B; Bowen, Jennifer L

    2018-01-01

    Salt marshes provide many key ecosystem services that have tremendous ecological and economic value. One critical service is the removal of fixed nitrogen from coastal waters, which limits the negative effects of eutrophication resulting from increased nutrient supply. Nutrient enrichment of salt marsh sediments results in higher rates of nitrogen cycling and, commonly, a concurrent increase in the flux of nitrous oxide, an important greenhouse gas. Little is known, however, regarding controls on the microbial communities that contribute to nitrous oxide fluxes in marsh sediments. To address this disconnect, we generated profiles of microbial communities and communities of micro-organisms containing specific nitrogen cycling genes that encode several enzymes ( amoA, norB, nosZ) related to nitrous oxide flux from salt marsh sediments. We hypothesized that communities of microbes responsible for nitrogen transformations will be structured by nitrogen availability. Taxa that respond positively to high nitrogen inputs may be responsible for the elevated rates of nitrogen cycling processes measured in fertilized sediments. Our data show that, with the exception of ammonia-oxidizing archaea, the community composition of organisms involved in the production and consumption of nitrous oxide was altered under nutrient enrichment. These results suggest that previously measured rates of nitrous oxide production and consumption are likely the result of changes in community structure, not simply changes in microbial activity.

  20. AIR POLLUTION CONTROL TECHNOLOGIES

    EPA Science Inventory

    This is a chapter for John Wiley & Son's Mechanical Engineers' Handbook, and covers issues involving air pollution control. Various technologies for controlling sulfur oxides is considered including fuel desulfurization. It also considers control of nitrogen oxides including post...

  1. [Anoxic bioremediation of urban polluted river water with biofilm].

    PubMed

    Zhang, Yong-Ming; Hu, Yi-Zhen; Yan, Rong; Liu, Fang

    2009-07-15

    Reactor like oxidation ditch was used for anaerobic bioremediation of urban river water, in which biofilm formed on ceramic honeycomb carrier was used instated of activated sludge. The dissolved oxygen in the wastewater was controlled under 0.5 mg/L for anoxic oxidation, and ammonia nitrogen was removed 40 to 60 percent, and total nitrogen removed 40 to 45 percent, that is ammonia nitrogen and total nitrogen were removed at the same time, also, nitrite was not any accumulated during the process. The biofilm was taken into flask to culture under anoxic oxidation condition in order to prove if anaerobic ammonium oxidation (ANAMMOX) occurred in the process, and ammonia and nitrite nitrogen were also removed at the same time in the experiment, which suggested that nitrification-denitrification and ANAMMOX occurred in bioremediation of urban surface water with low ratio of carbon and nitrogen at the same time. The anammox bacteria were existed in the biofilm according to molecular biological analysis. The experiment will be significant for bioremediation of eutrophication water body.

  2. Metabolism of Nitrogen Oxides in Ammonia-Oxidizing Bacteria

    NASA Astrophysics Data System (ADS)

    Kozlowski, J.; Stein, L. Y.

    2014-12-01

    Ammonia-oxidizing bacteria (AOB) are key microorganisms in the transformation of nitrogen intermediates in most all environments. Until recently there was very little work done to elucidate the physiology of ammonia-oxidizing bacteria cultivated from variable trophic state environments. With a greater variety of ammonia-oxidizers now in pure culture the importance of comparative physiological and genomic analysis is crucial. Nearly all known physiology of ammonia-oxidizing bacteria lies within the Nitrosomonas genus with Nitrosomonas europaea strain ATCC 19718 as the model. To more broadly characterize and understand the nature of obligate ammonia chemolithotrophy and the contribution of AOB to production of nitrogen oxides, Nitrosomonas spp. and Nitrosospira spp. isolated from variable trophic states and with sequenced genomes, were utilized. Instantaneous ammonia- and hydroxylamine-oxidation kinetics as a function of oxygen and substrate concentration were measured using an oxygen micro-sensor. The pathway intermediates nitric oxide and nitrous oxide were measured in real time using substrate-specific micro-sensors to elucidate whether production of these molecules is stoichiometric with rates of substrate oxidation. Genomic inventory was compared among the strains to identify specific pathways and modules to explain physiological differences in kinetic rates and production of N-oxide intermediates as a condition of their adaptation to different ammonium concentrations. This work provides knowledge of how nitrogen metabolism is differentially controlled in AOB that are adapted to different concentrations of ammonium. Overall, this work will provide further insight into the control of ammonia oxidizing chemolithotrophy across representatives of the Nitrosomonas and Nitrosospira genus, which can then be applied to examine additional genome-sequenced AOB isolates.

  3. 75 FR 64155 - Approval of Implementation Plans of Wisconsin: Nitrogen Oxides Reasonably Available Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-19

    ..., 2009. These revisions incorporate provisions related to the implementation of nitrogen oxides (NO X... ozone nonattainment areas. EPA is approving SIP revisions that address the NO X RACT requirements found in the Clean Air Act (CAA). EPA is also approving other miscellaneous rule changes that affect NO X...

  4. Soil nitrogen cycling and nitrous oxide flux in a Rocky Mountain Douglas-fir forest - Effects of fertilization, irrigation and carbon addition

    NASA Technical Reports Server (NTRS)

    Matson, Pamela A.; Gower, Stith T.; Volkmann, Carol; Billow, Christine; Grier, Charles C.

    1992-01-01

    Nitrous oxide fluxes and soil nitrogen transformations were measured in experimentally-treated high elevation Douglas-fir forests in northwestern New Mexico, USA. On an annual basis, forests that were fertilized with 200 kg N/ha emitted an average of 0.66 kg/ha of N2O-N, with highest fluxes occurring in July and August when soils were both warm and wet. Control, irrigated, and woodchip treated plots did not differ, and annual average fluxes ranged from 0.03 to 0.23 kg/ha. Annual net nitrogen mineralization and nitrate production were estimated in soil and forest floor using in situ incubations; fertilized soil mineralized 277 kg/ha/y in contrast to 18 kg/ha/y in control plots. Relative recovery of 15NH4-N applied to soil in laboratory incubations was principally in the form of NO3-N in the fertilized soils, while recovery was mostly in microbial biomass-N in the other treatments. Fertilization apparently added nitrogen that exceeded the heterotrophic microbial demand, resulting in higher rates of nitrate production and higher nitrous oxide fluxes. Despite the elevated nitrous oxide emission resulting from fertilization, we estimate that global inputs of nitrogen into forests are not currently contributing significantly to the increasing concentrations of nitrous oxide in the atmosphere.

  5. Evaluation of a novel oxidation ditch system for biological nitrogen and phosphorus removal from domestic sewage.

    PubMed

    Chen, X; Fujiwara, T; Ohtoshi, K; Inamori, S; Nakamachi, K; Tsuno, H

    2010-01-01

    A novel oxidation ditch system using anaerobic tanks and innovative dual dissolved oxygen (DO) control technology is proposed for biological nitrogen and phosphorus removal from domestic sewage. A continuous bench-scale experiment running for more than 300 days was performed to evaluate the system. Monitoring and controlling the airflow and recirculation flow rate independently using DO values at two points along the ditch permitted maintenance of aerobic and anoxic zone ratios of around 0.30 and 0.50, respectively. The ability to optimize aerobic and anoxic zone ratios using the dual DO control technology meant that a total nitrogen removal efficiency of 83.2-92.9% could be maintained. This remarkable nitrogen removal performance minimized the nitrate recycle to anaerobic tanks inhibiting the phosphorus release. Hence, the total phosphorus removal efficiency was also improved and ranged within 72.6-88.0%. These results demonstrated that stabilization of the aerobic and anoxic zone ratio by dual DO control technology not only resulted in a marked improvement of nitrogen removal, but it also enhanced phosphorus removal.

  6. EVALUATION OF TIRE-DERIVED FUEL FOR USE IN NITROGEN OXIDE REDUCTION BY REBURNING

    EPA Science Inventory

    Tire-derived fuel (TDF) was tested in a small-scale (44 kW or 150,000 Btu/hr) combustor to determine its feasibility as a fuel for use in reburning for control of nitrogen oxide (NO). TDF was gravity-fed into upward flowing combustion gases from a primary natural gas flame doped ...

  7. 76 FR 24372 - Approval and Promulgation of Air Quality Implementation Plans; Delaware; Update to Materials...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-02

    ... Emissions From Industrial Process Operations New Castle County.'' 12. Regulation 1112 ``Control of Nitrogen... the State Implementation Plans.'' 25. Regulation 1139 ``Nitrogen Oxides (NO X ) Budget Trading Program... by reference, Intergovernmental relations, Lead, Nitrogen dioxide, Ozone, Particulate matter...

  8. Soil nitrogen cycling and nitrous oxide flux in a Rocky Mountain Douglas-fir forest - Effects of fertilization, irrigation and carbon addition

    NASA Technical Reports Server (NTRS)

    Matson, Pamela A.; Gower, Stith T.; Volkmann, Carol; Billow, Christine; Grier, Charles C.

    1992-01-01

    Nitrous oxide fluxes and soil nitrogen transformations were measured in experimentally-treated high elevation Douglas-fir forests in northwestern New Mexico. On an annual basis, forests that were fertilized with 200 kg N/ha emitted an average of 0.66 kg/ha of N2O-N, with highest fluxes occurring in July and August when soils were both warm and wet. Control, irrigated, and woodchip treated plots were not different from each other, and annual average fluxes ranged from 0.03 to 0.23 kg/ha. Fertilized soil mineralized 277 kg/ha per year in contrast to 18 kg/ha per year in control plots. Relative recovery of (N-15)H4-N applied to soil in laboratory incubations was principally in the form of NO3-N in the fertilized soils, while recovery was mostly in microbial biomass-N in the other treatments. Fertilization apparently added nitrogen that exceeded the heterotrophic microbial demand, resulting in higher rates of nitrate production and higher nitrous oxide fluxes. Global inputs of nitrogen into forests are not currently contributing significantly to the increasing concentrations of nitrous oxide in the atmosphere.

  9. Cold blast furnace syndrome: a new source of toxic inhalation by nitrogen oxides.

    PubMed

    Tague, I; Llewellin, P; Burton, K; Buchan, R; Yates, D H

    2004-05-01

    To describe a new toxic inhalation syndrome in blast furnace workers. Fourteen workers developed acute respiratory symptoms shortly after exposure to "air blast" from blast furnace tuyeres. These included chest tightness, dyspnoea, rigors, and diaphoresis. Chest radiographs showed pulmonary infiltrates, and lung function a restrictive abnormality. This report includes a description of clinical features of the affected workers and elucidation of the probable cause of the outbreak. Clinical features and occupational hygiene measurements suggested the most likely cause was inhalation of nitrogen oxides at high pressure and temperature. While the task could not be eliminated, engineering controls were implemented to control the hazard. No further cases have occurred. "Cold blast furnace syndrome" represents a previously undescribed hazard of blast furnace work, probably due to inhalation of nitrogen oxides. It should be considered in the differential diagnosis of acute toxic inhalational injuries in blast furnace workers.

  10. Cold blast furnace syndrome: a new source of toxic inhalation by nitrogen oxides

    PubMed Central

    Tague, I; Llewellin, P; Burton, K; Buchan, R; Yates, D

    2004-01-01

    Methods: Fourteen workers developed acute respiratory symptoms shortly after exposure to "air blast" from blast furnace tuyeres. These included chest tightness, dyspnoea, rigors, and diaphoresis. Chest radiographs showed pulmonary infiltrates, and lung function a restrictive abnormality. This report includes a description of clinical features of the affected workers and elucidation of the probable cause of the outbreak. Results: Clinical features and occupational hygiene measurements suggested the most likely cause was inhalation of nitrogen oxides at high pressure and temperature. While the task could not be eliminated, engineering controls were implemented to control the hazard. No further cases have occurred. Conclusions: "Cold blast furnace syndrome" represents a previously undescribed hazard of blast furnace work, probably due to inhalation of nitrogen oxides. It should be considered in the differential diagnosis of acute toxic inhalational injuries in blast furnace workers. PMID:15090669

  11. Controlling sludge settleability in the oxidation ditch process.

    PubMed

    Hartley, K J

    2008-03-01

    This paper describes an investigation aimed at developing an operating technique for controlling sludge settleability in the oxidation ditch form of the nitrification denitrification activated sludge process. It was hypothesized that specific sludge volume index (SSVI) is lowest at an optimum process anoxic fraction and increases at higher and lower fractions. Using effluent ammonia:nitrate ratio as a surrogate for anoxic fraction, it was found that a simple empirical model based on a three solids retention time moving average nitrogen ratio was able to replicate the long-term SSVI variations in two independent oxidation ditches at a full-scale plant. Operating data from a second oxidation ditch plant during periods when a prefermenter was on- or off-line showed that SSVI also varies with RBCOD, greater RBCOD giving lower SSVI. It was concluded that best settleability occurs at about the same anoxic fraction as lowest effluent total nitrogen concentration, with an ammonia:nitrate ratio of about 1. An operating rule of thumb is to use dissolved oxygen control to maintain effluent ammonia and nitrate nitrogen concentrations about equal. A third oxidation ditch plant deliberately operated in this manner achieved 15-month median operating values for SSVI of 60mL/g and for effluent ammonia, nitrate and total N, respectively, of 0.2, 0.3 and 2.0mgN/L.

  12. An atmosphere protection subsystem in the thermal power station automated process control system

    NASA Astrophysics Data System (ADS)

    Parchevskii, V. M.; Kislov, E. A.

    2014-03-01

    Matters concerned with development of methodical and mathematical support for an atmosphere protection subsystem in the thermal power station automated process control system are considered taking as an example the problem of controlling nitrogen oxide emissions at a gas-and-oil-fired thermal power station. The combined environmental-and-economic characteristics of boilers, which correlate the costs for suppressing emissions with the boiler steam load and mass discharge of nitrogen oxides in analytic form, are used as the main tool for optimal control. A procedure for constructing and applying environmental-and-economic characteristics on the basis of technical facilities available in modern instrumentation and control systems is presented.

  13. Control of interfacial properties of Pr-oxide/Ge gate stack structure by introduction of nitrogen

    NASA Astrophysics Data System (ADS)

    Kato, Kimihiko; Kondo, Hiroki; Sakashita, Mitsuo; Nakatsuka, Osamu; Zaima, Shigeaki

    2011-06-01

    We have demonstrated the control of interfacial properties of Pr-oxide/Ge gate stack structure by the introduction of nitrogen. From C- V characteristics of Al/Pr-oxide/Ge 3N 4/Ge MOS capacitors, the interface state density decreases without the change of the accumulation capacitance after annealing. The TEM and TED measurements reveal that the crystallization of Pr-oxide is enhanced with annealing and the columnar structure of cubic-Pr 2O 3 is formed after annealing. From the depth profiles measured using XPS with Ar sputtering for the Pr-oxide/Ge 3N 4/Ge stack structure, the increase in the Ge component is not observed in a Pr-oxide film and near the interface between a Pr-oxide film and a Ge substrate. In addition, the N component segregates near the interface region, amorphous Pr-oxynitride (PrON) is formed at the interface. As a result, Pr-oxide/PrON/Ge stacked structure without the Ge-oxynitride interlayer is formed.

  14. Analysis of nitrification in agricultural soil and improvement of nitrogen circulation with autotrophic ammonia-oxidizing bacteria.

    PubMed

    Matsuno, Toshihide; Horii, Sachie; Sato, Takanobu; Matsumiya, Yoshiki; Kubo, Motoki

    2013-02-01

    Accumulations of inorganic nitrogen (NH₄⁺, NO₂⁻, and NO₃⁻) were analyzed to evaluate the nitrogen circulation activity in 76 agricultural soils. Accumulation of NH₄⁺ was observed, and the reaction of NH₄⁺→ NO₂⁻ appeared to be slower than that of NO₂⁻ → NO₃⁻ in agricultural soil. Two autotrophic and five heterotrophic ammonia-oxidizing bacteria (AOB) were isolated and identified from the soils, and the ammonia-oxidizing activities of the autotrophic AOB were 1.0 × 10³-1.0 × 10⁶ times higher than those of heterotrophic AOB. The relationship between AOB number, soil bacterial number, and ammonia-oxidizing activity was investigated with 30 agricultural soils. The ratio of autotrophic AOB number was 0.00032-0.26% of the total soil bacterial number. The soil samples rich in autotrophic AOB (>1.0 × 10⁴ cells/g soil) had a high nitrogen circulation activity, and additionally, the nitrogen circulation in the agricultural soil was improved by controlling the autotrophic AOBs.

  15. Removal of nitrogen oxides from gas streams by biofiltration

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Barrett, K.B.; Barnes, J.M.; Apel, W.A.

    1994-12-31

    Nitrogen oxides (NO{sub x}) are primary air pollutants and, as such, there is considerable interest in the development of efficient, cost effective technologies to remediate NO{sub x} containing emissions. Biofiltration involves the venting of contaminated gas streams through biologically active material such as soil or compost. This technology has been used successfully to control odors as well as volatile organic compounds from a variety of industrial and public sources. The purpose of this study was to evaluate the feasibility of using biofiltration to convert NO{sub x} to nitrogen gas.

  16. 40 CFR 52.770 - Identification of plan.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... “Underfire″ defined 9/26/1980 11/5/1981, 46 FR 54943. 1-2-88 “Vapor balance system″ defined 9/26/1980 11/5... Emission Rules 9-1 Carbon Monoxide Emission Limits 12/15/2002 11/30/2004, 69 FR 69531. Article 10. Nitrogen Oxides Rules 10-1 Nitrogen Oxides Control in Clark and Floyd Counties 6/12/1996 6/3/1997, 62 FR 30253. 10...

  17. 40 CFR 52.770 - Identification of plan.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... “Underfire″ defined 9/26/1980 11/5/1981, 46 FR 54943. 1-2-88 “Vapor balance system″ defined 9/26/1980 11/5...-1 Carbon Monoxide Emission Limits 12/15/2002 11/30/2004, 69 FR 69531. Article 10. Nitrogen Oxides Rules 10-1 Nitrogen Oxides Control in Clark and Floyd Counties 6/12/1996 6/3/1997, 62 FR 30253. 10-3...

  18. 78 FR 78315 - Revision to the Idaho State Implementation Plan; Approval of Fine Particulate Matter Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-26

    ... ), nitrogen oxides (NO X ), volatile organic compounds (VOC), and ammonia. An analysis of the baseline year... Idaho Transportation Department agreed to use straight salt and liquid salt brine throughout Franklin.... List of Subjects in 40 CFR Part 52 Environmental protection, Air pollution control, Nitrogen dioxide...

  19. High growth potential and nitrogen removal performance of marine anammox bacteria in shrimp-aquaculture sediment.

    PubMed

    Van Duc, Luong; Song, Bongkeun; Ito, Hiroaki; Hama, Takehide; Otani, Masashi; Kawagoshi, Yasunori

    2018-04-01

    Anaerobic ammonium oxidation (anammox) bacteria were enriched in continuous packed-bed columns with marine sediment. One column (SB-C) was packed with only marine sediment collected from a shrimp-aquaculture pond, and another column (SB-AMX) was inoculated with marine anammox bacteria (MAB) as a control. These columns were continuously fed with natural or artificial seawater including ammonium (NH 4 + ) and nitrite (NO 2 - ). The SB-AMX showed anammox activities from the beginning and continued for over 200 days. However, the SB-C had no nitrogen removal performance for over 170 days. After adding a bicarbonate solution (KHCO 3 ) to the sediment-only packed column, anammox activity was observed within 13 days. The column exhibited a nitrogen removal efficiency (NRE) of 88% at a nitrogen loading rate (NLR) of 1.0 kg-N·m -3 ·day -1 , which was comparable to the control one. A next-generation sequencing analysis revealed the predominance of MAB related to "Candidatus Scalindua spp.". In addition, the co-occurrence of sulfur-oxidizing denitrifiers was observed, which suggests their symbiotic relationship. This study suggests the applicability of MAB for in-situ bioremediation of nitrogen-contaminated marine sediments and reveals a potential microbial interaction between anammox and sulfur-oxidizing communities responsible for nitrogen and sulfur cycling in marine aquaculture systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Nitrogen Oxide Emission, Economic Growth and Urbanization in China: a Spatial Econometric Analysis

    NASA Astrophysics Data System (ADS)

    Zhou, Zhimin; Zhou, Yanli; Ge, Xiangyu

    2018-01-01

    This research studies the nexus of nitrogen oxide emissions and economic development/urbanization. Under the environmental Kuznets curve (EKC) hypothesis, we apply the analysis technique of spatial panel data in the STIRPAT framework, and thus obtain the estimated impacts of income/urbanization on nitrogen oxide emission systematically. The empirical findings suggest that spatial dependence on nitrogen oxide emission distribution exist at provincial level, and the inverse N-shape EKC describes both income-nitrogen oxide and urbanization-nitrogen oxide nexuses. In addition, some well-directed policy advices are made to reduce the nitrogen oxide emission in future.

  1. Implications of a More Comprehensive Nitrogen Cycle in a Global Biogeochemical Ocean Model

    NASA Astrophysics Data System (ADS)

    Six, K. D.; Ilyina, T.

    2016-02-01

    Nitrogen plays a crucial role for nearly all living organisms in the Earth system. Changes in the marine nitrogen cycle not only alter the marine biota, but will also have an impact on the marine carbon cycle and, in turn, on climate due to the close coupling of the carbon-nitrogen cycle. The understanding of processes and controls of the marine nitrogen cycle is therefore a prerequisite to reduce uncertainties in the prediction of future climate. Nevertheless, most ocean biogeochemical components of modern Earth system models have a rather simplistic representation of marine N-cycle mainly focusing on nitrate. Here we present results of the HAMburg Ocean Carbon Cycle model (HAMOCC) as part of the MPI-ESM which was extended by a prognostic representation of ammonium and nitrite to resolve important processes of the marine N-cycle such as nitrification and anaerobic ammonium oxidation (anammox). Additionally, we updated the production of nitrous oxide, an important greenhouse gas, allowing for two sources from oxidation of ammonium (nitrification) and from reduction of nitrite (nitrifier-denitrification) at low oxygen concentrations. Besides an extended model data comparison we discuss the following aspects of the N-cycle by model means: (1) contribution of anammox to the loss of fixed nitrogen, and (2) production and emission of marine nitrous oxide.

  2. 40 CFR 86.318-79 - Oxides of nitrogen analyzer specifications.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 19 2013-07-01 2013-07-01 false Oxides of nitrogen analyzer... Procedures § 86.318-79 Oxides of nitrogen analyzer specifications. (a) Oxides of nitrogen are to be measured....327. (b) Option. The oxides of nitrogen may be measured with an NDIR analyzer system that meets the...

  3. 40 CFR 86.318-79 - Oxides of nitrogen analyzer specifications.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Oxides of nitrogen analyzer... Procedures § 86.318-79 Oxides of nitrogen analyzer specifications. (a) Oxides of nitrogen are to be measured....327. (b) Option. The oxides of nitrogen may be measured with an NDIR analyzer system that meets the...

  4. 40 CFR 86.318-79 - Oxides of nitrogen analyzer specifications.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Oxides of nitrogen analyzer... Procedures § 86.318-79 Oxides of nitrogen analyzer specifications. (a) Oxides of nitrogen are to be measured....327. (b) Option. The oxides of nitrogen may be measured with an NDIR analyzer system that meets the...

  5. Procedures of laboratory nitric oxide fumigation for pest control

    USDA-ARS?s Scientific Manuscript database

    Nitric oxide (NO) is a newly discovered fumigant and has the potential to be a safe and effective alternative for postharvest pest control. As NO reacts with oxygen spontaneously to produce nitrogen dioxide, NO fumigation must be conducted under ultralow oxygen (ULO) atmosphere and therefore has com...

  6. The position of gas turbine power plants with respect to the emission of nitrogen oxides by fossil-fueled energy installations

    NASA Technical Reports Server (NTRS)

    Kaiser, E.

    1977-01-01

    The amount of nitrogen oxides introduced into the atmosphere by gas turbines is very significant in relation to the total amount of nitrogen oxide emissions produced by chemical installations and combustion engines. Turbine manufacturers are therefore working to develop combustion chambers with sufficiently low nitrogen oxide emission concentrations. Attention is given to aspects of nitrogen oxide formation in gas turbines, the parameters which determine this formation, and suitable approaches to reducing nitrogen oxide emissions.

  7. 40 CFR 50.11 - National primary and secondary ambient air quality standards for oxides of nitrogen (with...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... air quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). 50.11 Section... quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). (a) The level of the national primary annual ambient air quality standard for oxides of nitrogen is 53 parts per billion (ppb...

  8. 40 CFR 50.11 - National primary and secondary ambient air quality standards for oxides of nitrogen (with...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... air quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). 50.11 Section... quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). (a) The level of the national primary annual ambient air quality standard for oxides of nitrogen is 53 parts per billion (ppb...

  9. 40 CFR 50.11 - National primary and secondary ambient air quality standards for oxides of nitrogen (with...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... air quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). 50.11 Section... quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). (a) The level of the national primary annual ambient air quality standard for oxides of nitrogen is 53 parts per billion (ppb...

  10. Enhancing nitrogen removal in an Orbal oxidation ditch by optimization of oxygen supply: practice in a full-scale municipal wastewater treatment plant.

    PubMed

    Zhou, Xin; Guo, Xuesong; Han, Yunping; Liu, Junxin; Ren, Jincheng; Wang, Yu; Guo, Yantao

    2012-09-01

    Seven different aeration modes, in which oxygen supply was changed by adjusting the number of aerators, were designed and applied in a full-scale municipal wastewater treatment plant with Orbal oxidation ditch to investigate the influence of dissolved oxygen (DO) on nitrogen removal performance. The full-scale experiment results of 574 days showed that nitrogen removal efficiency depended on the degree of nitrification and denitrification in the outer channel, which was the largest contributor for TN removal in the Orbal oxidation ditch. Appropriate aeration control in the outer channel was essential to balance nitrification and denitrification in the Orbal oxidation ditch. When DO was as low as about 0.2 mg/L in the outer channel, the highest TN removal efficiency of 75% was obtained. Microbial analysis confirmed that aerobic and anaerobic bacteria coexisted in the outer channel. The greater species diversity and more intensive activities of these bacteria in aeration Mode V may be responsible for the higher TN removal efficiency compared with Mode III. These results suggest that different aerated conditions in the Orbal oxidation ditch might have a significant effect on microbial community characteristics and nitrogen removal efficiencies.

  11. Position Paper: NO equals x Measurement

    ERIC Educational Resources Information Center

    Hauser, Thomas R.; Shy, Carl M.

    1972-01-01

    Doubts about the accuracy of measured concentrations of nitrogen dioxide (NO 2) in ambient air have led the Environmental Protection Agency to reassess both the analytical technique and the extent to which nitrogen oxides (NO equals x) control will need to satisfy federal laws. (BL)

  12. Effects of biochar addition to soil on nitrogen fluxes in a winter wheat lysimeter experiment

    NASA Astrophysics Data System (ADS)

    Hüppi, Roman; Leifeld, Jens; Neftel, Albrecht; Conen, Franz; Six, Johan

    2014-05-01

    Biochar is a carbon-rich, porous residue from pyrolysis of biomass that potentially increases crop yields by reducing losses of nitrogen from soils and/or enhancing the uptake of applied fertiliser by the crops. Previous research is scarce about biochar's ability to increase wheat yields in temperate soils or how it changes nitrogen dynamics in the field. In a lysimeter system with two different soils (sandy/silt loam) nitrogen fluxes were traced by isotopic 15N enriched fertiliser to identify changes in nitrous oxide emissions, leaching and plant uptake after biochar addition. 20t/ha woodchip-waste biochar (pH=13) was applied to these soils in four lysimeters per soil type; the same number of lysimeters served as a control. The soils were cropped with winter wheat during the season 2012/2013. 170 kg-N/ha ammonium nitrate fertiliser with 10% 15N was applied in 3 events during the growing season and 15N concentrations where measured at different points in time in plant, soil, leachate and emitted nitrous oxide. After one year the lysimeter system showed no difference between biochar and control treatment in grain- and straw yield or nitrogen uptake. However biochar did reduce nitrous oxide emissions in the silt loam and losses of nitrate leaching in sandy loam. This study indicates potential reduction of nitrogen loss from cropland soil by biochar application but could not confirm increased yields in an intensive wheat production system.

  13. Nitrogen and Oxygen Isotope Effects of Ammonia Oxidation by Thermophilic Thaumarchaeota from a Geothermal Water Stream

    PubMed Central

    Sakai, Sanae; Konno, Uta; Nakahara, Nozomi; Takaki, Yoshihiro; Saito, Yumi; Imachi, Hiroyuki; Tasumi, Eiji; Makabe, Akiko; Koba, Keisuke; Takai, Ken

    2016-01-01

    ABSTRACT Ammonia oxidation regulates the balance of reduced and oxidized nitrogen pools in nature. Although ammonia-oxidizing archaea have been recently recognized to often outnumber ammonia-oxidizing bacteria in various environments, the contribution of ammonia-oxidizing archaea is still uncertain due to difficulties in the in situ quantification of ammonia oxidation activity. Nitrogen and oxygen isotope ratios of nitrite (δ15NNO2− and δ18ONO2−, respectively) are geochemical tracers for evaluating the sources and the in situ rate of nitrite turnover determined from the activities of nitrification and denitrification; however, the isotope ratios of nitrite from archaeal ammonia oxidation have been characterized only for a few marine species. We first report the isotope effects of ammonia oxidation at 70°C by thermophilic Thaumarchaeota populations composed almost entirely of “Candidatus Nitrosocaldus.” The nitrogen isotope effect of ammonia oxidation varied with ambient pH (25‰ to 32‰) and strongly suggests the oxidation of ammonia, not ammonium. The δ18O value of nitrite produced from ammonia oxidation varied with the δ18O value of water in the medium but was lower than the isotopic equilibrium value in water. Because experiments have shown that the half-life of abiotic oxygen isotope exchange between nitrite and water is longer than 33 h at 70°C and pH ≥6.6, the rate of ammonia oxidation by thermophilic Thaumarchaeota could be estimated using δ18ONO2− in geothermal environments, where the biological nitrite turnover is likely faster than 33 h. This study extended the range of application of nitrite isotopes as a geochemical clock of the ammonia oxidation activity to high-temperature environments. IMPORTANCE Because ammonia oxidation is generally the rate-limiting step in nitrification that regulates the balance of reduced and oxidized nitrogen pools in nature, it is important to understand the biological and environmental factors underlying the regulation of the rate of ammonia oxidation. The discovery of ammonia-oxidizing archaea (AOA) in marine and terrestrial environments has transformed the concept that ammonia oxidation is operated only by bacterial species, suggesting that AOA play a significant role in the global nitrogen cycle. However, the archaeal contribution to ammonia oxidation in the global biosphere is not yet completely understood. This study successfully identified key factors controlling nitrogen and oxygen isotopic ratios of nitrite produced from thermophilic Thaumarchaeota and elucidated the applicability and its limit of nitrite isotopes as a geochemical clock of ammonia oxidation rate in nature. Oxygen isotope analysis in this study also provided new biochemical information on archaeal ammonia oxidation. PMID:27208107

  14. Nitrogen and Oxygen Isotope Effects of Ammonia Oxidation by Thermophilic Thaumarchaeota from a Geothermal Water Stream.

    PubMed

    Nishizawa, Manabu; Sakai, Sanae; Konno, Uta; Nakahara, Nozomi; Takaki, Yoshihiro; Saito, Yumi; Imachi, Hiroyuki; Tasumi, Eiji; Makabe, Akiko; Koba, Keisuke; Takai, Ken

    2016-08-01

    Ammonia oxidation regulates the balance of reduced and oxidized nitrogen pools in nature. Although ammonia-oxidizing archaea have been recently recognized to often outnumber ammonia-oxidizing bacteria in various environments, the contribution of ammonia-oxidizing archaea is still uncertain due to difficulties in the in situ quantification of ammonia oxidation activity. Nitrogen and oxygen isotope ratios of nitrite (δ(15)NNO2- and δ(18)ONO2-, respectively) are geochemical tracers for evaluating the sources and the in situ rate of nitrite turnover determined from the activities of nitrification and denitrification; however, the isotope ratios of nitrite from archaeal ammonia oxidation have been characterized only for a few marine species. We first report the isotope effects of ammonia oxidation at 70°C by thermophilic Thaumarchaeota populations composed almost entirely of "Candidatus Nitrosocaldus." The nitrogen isotope effect of ammonia oxidation varied with ambient pH (25‰ to 32‰) and strongly suggests the oxidation of ammonia, not ammonium. The δ(18)O value of nitrite produced from ammonia oxidation varied with the δ(18)O value of water in the medium but was lower than the isotopic equilibrium value in water. Because experiments have shown that the half-life of abiotic oxygen isotope exchange between nitrite and water is longer than 33 h at 70°C and pH ≥6.6, the rate of ammonia oxidation by thermophilic Thaumarchaeota could be estimated using δ(18)ONO2- in geothermal environments, where the biological nitrite turnover is likely faster than 33 h. This study extended the range of application of nitrite isotopes as a geochemical clock of the ammonia oxidation activity to high-temperature environments. Because ammonia oxidation is generally the rate-limiting step in nitrification that regulates the balance of reduced and oxidized nitrogen pools in nature, it is important to understand the biological and environmental factors underlying the regulation of the rate of ammonia oxidation. The discovery of ammonia-oxidizing archaea (AOA) in marine and terrestrial environments has transformed the concept that ammonia oxidation is operated only by bacterial species, suggesting that AOA play a significant role in the global nitrogen cycle. However, the archaeal contribution to ammonia oxidation in the global biosphere is not yet completely understood. This study successfully identified key factors controlling nitrogen and oxygen isotopic ratios of nitrite produced from thermophilic Thaumarchaeota and elucidated the applicability and its limit of nitrite isotopes as a geochemical clock of ammonia oxidation rate in nature. Oxygen isotope analysis in this study also provided new biochemical information on archaeal ammonia oxidation. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  15. Polypyrrole-derived nitrogen and oxygen co-doped mesoporous carbons as efficient metal-free electrocatalyst for hydrazine oxidation.

    PubMed

    Meng, Yuying; Zou, Xiaoxin; Huang, Xiaoxi; Goswami, Anandarup; Liu, Zhongwu; Asefa, Tewodros

    2014-10-08

    We demonstrate that polypyrrole-derived nitrogen and oxygen co-doped mesoporous carbons can serve as efficient, metal-free electrocatalysts for hydrazine oxidation reaction, with low overpotential and high current density. The materials' structures and the nature and type of their included dopants, which can be controlled by varying the synthetic conditions, can affect the electrocatalytic properties of the materials. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. NO-assisted molecular-beam epitaxial growth of nitrogen substituted EuO

    NASA Astrophysics Data System (ADS)

    Wicks, R.; Altendorf, S. G.; Caspers, C.; Kierspel, H.; Sutarto, R.; Tjeng, L. H.; Damascelli, A.

    2012-04-01

    We have investigated a method for substituting oxygen with nitrogen in EuO thin films, which is based on molecular beam epitaxy distillation with NO gas as the oxidizer. By varying the NO gas pressure, we produce crystalline, epitaxial EuO1 -xNx films with good control over the films' nitrogen concentration. In situ x-ray photoemission spectroscopy reveals that nitrogen substitution is connected to the formation Eu3+4f6 and a corresponding decrease in the number of Eu2+4f7, indicating that nitrogen is being incorporated in its 3- oxidation state. While small amounts of Eu3+ in over-oxidized Eu1-δO thin films lead to a drastic suppression of the ferromagnetism, the formation of Eu3+ in EuO1-xNx still allows the ferromagnetic phase to exist with an unaffected Tc, thus providing an ideal model system to study the interplay between the magnetic f7 (J = 7/2) and the non-magnetic f6 (J = 0) states close to the Fermi level.

  17. 40 CFR 86.523-78 - Oxides of nitrogen analyzer calibration.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 19 2013-07-01 2013-07-01 false Oxides of nitrogen analyzer... Emission Regulations for 1978 and Later New Motorcycles; Test Procedures § 86.523-78 Oxides of nitrogen... nitrogen are measured, the chemiluminescent oxides of nitrogen analyzer must be checked for NO2 to NO...

  18. 40 CFR 86.523-78 - Oxides of nitrogen analyzer calibration.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Oxides of nitrogen analyzer... Emission Regulations for 1978 and Later New Motorcycles; Test Procedures § 86.523-78 Oxides of nitrogen... nitrogen are measured, the chemiluminescent oxides of nitrogen analyzer must be checked for NO2 to NO...

  19. Minimizing nitrous oxide in biological nutrient removal from municipal wastewater by controlling copper ion concentrations.

    PubMed

    Zhu, Xiaoyu; Chen, Yinguang; Chen, Hong; Li, Xiang; Peng, Yongzhen; Wang, Shuying

    2013-02-01

    In this study, nitrous oxide (N(2)O) production during biological nutrient removal (BNR) from municipal wastewater was reported to be remarkably reduced by controlling copper ion (Cu(2+)) concentration. Firstly, it was observed that the addition of Cu(2+) (10-100 μg/L) reduced N(2)O generation by 54.5-73.2 % and improved total nitrogen removal when synthetic wastewater was treated in an anaerobic-aerobic (with low dissolved oxygen) BNR process. Then, the roles of Cu(2+) were investigated. The activities of nitrite and nitrous oxide reductases were increased by Cu(2+) addition, which accelerated the bio-reductions of both nitrite to nitric oxide (NO (2) (-)  → NO) and nitrous oxide to nitrogen gas (N(2)O → N(2)). The quantitative real-time polymerase chain reaction assay indicated that Cu(2+) addition increased the number of N(2)O reducing denitrifiers. Further investigation showed that more polyhydoxyalkanoates were utilized in the Cu(2+)-added system for denitrification. Finally, the feasibility of reducing N(2)O generation by controlling Cu(2+) was examined in two other BNR processes treating real municipal wastewater. As the Cu(2+) in municipal wastewater is usually below 10 μg/L, according to this study, the supplement of influent Cu(2+) to a concentration of 10-100 μg/L is beneficial to reduce N(2)O emission and improve nitrogen removal when sludge concentration in the BNR system is around 3,200 mg/L.

  20. Effect of radiation, heat, and aging on in vitro wear resistance of polyethylene.

    PubMed

    Muratoglu, Orhun K; Merrill, Edward W; Bragdon, Charles R; O'Connor, Daniel; Hoeffel, Daniel; Burroughs, Brian; Jasty, Murali; Harris, William H

    2003-12-01

    Radiation cross-linking increases the wear resistance of polyethylene used in total hip replacement. Radiation also generates residual free radicals, which are detrimental to long-term properties of polyethylene. Two approaches are used to stabilize the residual free radicals and terminally sterilize the components. One is postirradiation annealing with gas sterilization and the other is postirradiation melting with gamma sterilization in nitrogen. The hypothesis of the current study is that postirradiation annealing followed by gamma sterilization in nitrogen will result in more free radicals in polyethylene than gamma sterilization either in air or in nitrogen alone. To test this hypothesis, concentration of residual free radicals was quantified in polyethylene that was annealed and gamma sterilized in nitrogen and control polyethylenes gamma sterilized in air versus in nitrogen. Three crosslinked polyethylenes that were melted and gas sterilized also were included in the study. The effects of residual free radicals were studied by accelerated aging. Oxidation levels and weight loss in bidirectional pin-on-disk tests were determined before and after aging. Polyethylene that was subjected to postirradiation annealing and gamma sterilization resulted in 58% more residual free radicals than control polyethylenes. Weight loss of the annealed polyethylene increased by 16-fold on accelerated aging and had three times higher oxidation levels than that measured in control polyethylenes after aging. In contrast, polyethylenes that were stabilized with postirradiation melting and terminally gas sterilized showed no detectable residual free radicals. Accelerated aging did not affect the weight loss and oxidation levels of melted polyethylenes.

  1. Nitrification in a completely stirred tank reactor treating the liquid phase of digestate: The way towards rational use of nitrogen.

    PubMed

    Svehla, Pavel; Radechovska, Helena; Pacek, Lukas; Michal, Pavel; Hanc, Ales; Tlustos, Pavel

    2017-06-01

    The nitrification of the liquid phase of digestate (LPD) was conducted using a 5L completely stirred tank reactor (CSTR) in two independent periods (P1 - without pH control; P2 - with pH control). The possibility of minimizing nitrogen losses during the application of LPD to the soil as well as during long-term storage or thermal thickening of LPD using nitrification was discussed. Moreover, the feasibility of applying the nitrification of LPD to the production of electron acceptors for biological desulfurization of biogas was assessed. Despite an extremely high average concentration of ammonia and COD in LPD reaching 2470 and 9080mg/L, respectively, nitrification was confirmed immediately after the start-up of the CSTR. N-NO 3 - concentration reached 250mg/L only two days after the start of P1. On the other hand, P1 demonstrated that working without pH control is a risk because of the free nitrous acid (FNA) inhibition towards nitrite oxidizing bacteria (NOB) resulting in massive nitrite accumulation. Up to 30.9mg/L of FNA was present in the reactor during P1, where the NOB started to be inhibited even at 0.15mg/L of FNA. During P2, the control of pH at 7.0 resulted in nitrogen oxidation efficiency reaching 98.3±1.5% and the presence of N-NO 3 - among oxidized nitrogen 99.6±0.4%. The representation of volatile free ammonia within total nitrogen was reduced more than 1000 times comparing with raw LPD under these conditions. Thus, optimum characteristics of the tested system from the point of view of minimizing the nitrogen losses as well as production of electron acceptors for the desulfurization of biogas were gained in this phase of reactor operation. Based on the results of the experiments, potential improvements and modifications of the tested system were suggested. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Analysis of microbial community and nitrogen transition with enriched nitrifying soil microbes for organic hydroponics.

    PubMed

    Saijai, Sakuntala; Ando, Akinori; Inukai, Ryuya; Shinohara, Makoto; Ogawa, Jun

    2016-06-27

    Nitrifying microbial consortia were enriched from bark compost in a water system by regulating the amounts of organic nitrogen compounds and by controlling the aeration conditions with addition of CaCO 3 for maintaining suitable pH. Repeated enrichment showed reproducible mineralization of organic nitrogen via the conversion of ammonium ions ([Formula: see text]) and nitrite ions ([Formula: see text]) into nitrate ions ([Formula: see text]). The change in microbial composition during the enrichment was investigated by PCR-DGGE analysis with a focus on prokaryote, ammonia-oxidizing bacteria, nitrite-oxidizing bacteria, and eukaryote cell types. The microbial transition had a simple profile and showed clear relation to nitrogen ions transition. Nitrosomonas and Nitrobacter were mainly detected during [Formula: see text] and [Formula: see text] oxidation, respectively. These results revealing representative microorganisms acting in each ammonification and nitrification stages will be valuable for the development of artificial simple microbial consortia for organic hydroponics that consisted of identified heterotrophs and autotrophic nitrifying bacteria.

  3. Silicon oxynitride films deposited by reactive high power impulse magnetron sputtering using nitrous oxide as a single-source precursor

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hänninen, Tuomas, E-mail: tuoha@ifm.liu.se; Schmidt, Susann; Jensen, Jens

    2015-09-15

    Silicon oxynitride thin films were synthesized by reactive high power impulse magnetron sputtering of silicon in argon/nitrous oxide plasmas. Nitrous oxide was employed as a single-source precursor supplying oxygen and nitrogen for the film growth. The films were characterized by elastic recoil detection analysis, x-ray photoelectron spectroscopy, x-ray diffraction, x-ray reflectivity, scanning electron microscopy, and spectroscopic ellipsometry. Results show that the films are silicon rich, amorphous, and exhibit a random chemical bonding structure. The optical properties with the refractive index and the extinction coefficient correlate with the film elemental composition, showing decreasing values with increasing film oxygen and nitrogen content.more » The total percentage of oxygen and nitrogen in the films is controlled by adjusting the gas flow ratio in the deposition processes. Furthermore, it is shown that the film oxygen-to-nitrogen ratio can be tailored by the high power impulse magnetron sputtering-specific parameters pulse frequency and energy per pulse.« less

  4. 75 FR 12168 - Approval and Promulgation of Air Quality Implementation Plans; Delaware; Control of Nitrogen...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-15

    ... Boilers and Process Heaters at Petroleum Refineries AGENCY: Environmental Protection Agency (EPA). ACTION... from Industrial Boilers and Process Heaters at Petroleum Refineries to Delaware's Regulation No. 1142... Nitrogen Oxide Emissions from Industrial Boilers and Process Heaters at Petroleum Refineries. The...

  5. Design and evaluation of combustors for reducing aircraft engine pollution

    NASA Technical Reports Server (NTRS)

    Jones, R. E.; Grobman, J.

    1973-01-01

    Various techniques and test results are briefly described and referenced for detail. The effort arises from the increasing concern for the measurement and control of emissions from gas turbine engines. The greater part of this research is focused on reducing the oxides of nitrogen formed during takeoff and cruise in both advanced CTOL, high pressure ratio engines, and advanced supersonic aircraft engines. The experimental approaches taken to reduce oxides of nitrogen emissions include the use of: multizone combustors incorporating reduced dwell time, fuel-air premixing, air atomization, fuel prevaporization, water injection, and gaseous fuels. In the experiments conducted to date, some of these techniques were more successful than others in reducing oxides of nitrogen emissions. Tests are being conducted on full-annular combustors at pressures up to 6 atmospheres and on combustor segments at pressures up to 30 atmospheres.

  6. System and method for controlling ammonia levels in a selective catalytic reduction catalyst using a nitrogen oxide sensor

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    None

    A system according to the principles of the present disclosure includes an air/fuel ratio determination module and an emission level determination module. The air/fuel ratio determination module determines an air/fuel ratio based on input from an air/fuel ratio sensor positioned downstream from a three-way catalyst that is positioned upstream from a selective catalytic reduction (SCR) catalyst. The emission level determination module selects one of a predetermined value and an input based on the air/fuel ratio. The input is received from a nitrogen oxide sensor positioned downstream from the three-way catalyst. The emission level determination module determines an ammonia level basedmore » on the one of the predetermined value and the input received from the nitrogen oxide sensor.« less

  7. Substrate and nutrient limitation of ammonia-oxidizing bacteria and archaea in temperate forest soil

    Treesearch

    J.S. Norman; J.E. Barrett

    2014-01-01

    Ammonia-oxidizing microbes control the rate-limiting step of nitrification, a critical ecosystem process, which affects retention and mobility of nitrogen in soil ecosystems. This study investigated substrate (NH4þ) and nutrient (K and P) limitation of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) in temperate forest soils at Coweeta Hydrologic...

  8. Regulation of nitrogen metabolism by GATA zinc finger transcription factors in Yarrowia lipolytica

    DOE PAGES

    Pomraning, Kyle R.; Bredeweg, Erin L.; Baker, Scott E.; ...

    2017-02-15

    Here, fungi accumulate lipids in a manner dependent on the quantity and quality of the nitrogen source on which they are growing. In the oleaginous yeast Yarrowia lipolytica, growth on a complex source of nitrogen enables rapid growth and limited accumulation of neutral lipids, while growth on a simple nitrogen source promotes lipid accumulation in large lipid droplets. Here we examined the roles of nitrogen catabolite repression and its regulation by GATA zinc finger transcription factors on lipid metabolism in Y. lipolytica. Deletion of the GATA transcription factor genes gzf3 and gzf2 resulted in nitrogen source-specific growth defects and greatermore » accumulation of lipids when the cells were growing on a simple nitrogen source. Deletion of gzf1, which is most similar to activators of genes repressed by nitrogen catabolite repression in filamentous ascomycetes, did not affect growth on the nitrogen sources tested. We examined gene expression of wild-type and GATA transcription factor mutants on simple and complex nitrogen sources and found that expression of enzymes involved in malate metabolism, beta-oxidation, and ammonia utilization are strongly upregulated on a simple nitrogen source. Deletion of gzf3 results in overexpression of genes with GATAA sites in their promoters, suggesting that it acts as a repressor, while gzf2 is required for expression of ammonia utilization genes but does not grossly affect the transcription level of genes predicted to be controlled by nitrogen catabolite repression. Both GATA transcription factor mutants exhibit decreased expression of genes controlled by carbon catabolite repression via the repressor mig1, including genes for beta-oxidation, highlighting the complex interplay between regulation of carbon, nitrogen, and lipid metabolism.« less

  9. Regulation of nitrogen metabolism by GATA zinc finger transcription factors in Yarrowia lipolytica

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pomraning, Kyle R.; Bredeweg, Erin L.; Baker, Scott E.

    Here, fungi accumulate lipids in a manner dependent on the quantity and quality of the nitrogen source on which they are growing. In the oleaginous yeast Yarrowia lipolytica, growth on a complex source of nitrogen enables rapid growth and limited accumulation of neutral lipids, while growth on a simple nitrogen source promotes lipid accumulation in large lipid droplets. Here we examined the roles of nitrogen catabolite repression and its regulation by GATA zinc finger transcription factors on lipid metabolism in Y. lipolytica. Deletion of the GATA transcription factor genes gzf3 and gzf2 resulted in nitrogen source-specific growth defects and greatermore » accumulation of lipids when the cells were growing on a simple nitrogen source. Deletion of gzf1, which is most similar to activators of genes repressed by nitrogen catabolite repression in filamentous ascomycetes, did not affect growth on the nitrogen sources tested. We examined gene expression of wild-type and GATA transcription factor mutants on simple and complex nitrogen sources and found that expression of enzymes involved in malate metabolism, beta-oxidation, and ammonia utilization are strongly upregulated on a simple nitrogen source. Deletion of gzf3 results in overexpression of genes with GATAA sites in their promoters, suggesting that it acts as a repressor, while gzf2 is required for expression of ammonia utilization genes but does not grossly affect the transcription level of genes predicted to be controlled by nitrogen catabolite repression. Both GATA transcription factor mutants exhibit decreased expression of genes controlled by carbon catabolite repression via the repressor mig1, including genes for beta-oxidation, highlighting the complex interplay between regulation of carbon, nitrogen, and lipid metabolism.« less

  10. Nitrogen oxides from burning forest fuels examined by thermogravimetry and evolved gas analysis

    Treesearch

    H.B. Clements; Charles K. McMahon

    1980-01-01

    Abstract. Twelve forest fuels that varied widely in nitrogen content were burned in a thermogravimetric system, and nitrogen oxide production was analyzed by chemiluminescence. The effects of fuel nitrogen concentration, available oxygen, flow rate, and heating rate on nitrogen oxide production were examined.Results show that fuel nitrogen is an...

  11. 75 FR 56 - Approval and Promulgation of Implementation Plans and Designation of Areas for Air Quality...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-04

    ..., from the State of Tennessee, through the Tennessee Department of Environment and Conservation (TDEC..., 2009, 2017, and 2021 motor vehicle emission budgets (MVEBs) for nitrogen oxides (NO X ) and volatile... protection, Air pollution control, Intergovernmental relations, Incorporation by reference, Nitrogen dioxide...

  12. 75 FR 47218 - Approval and Promulgation of Implementation Plans and Designation of Areas for Air Quality...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-05

    ... Kentucky, through the Kentucky Energy and Environment Cabinet, Division for Air Quality (DAQ), to... (MVEBs) for nitrogen oxides (NO X ) and volatile organic compounds (VOC) for Northern Kentucky. This... control, Incorporation by reference, Nitrogen dioxide, Ozone, Intergovernmental relations, and Volatile...

  13. Proceedings of the NASA/Florida Institute of Technology Environmental Engineering Conference on Nitrogen Tetroxide. [with emphasis on space shuttle

    NASA Technical Reports Server (NTRS)

    Rhodes, E. L.

    1978-01-01

    Methods of reducing the user hazards of nitrogen tetroxide, a hypergolic oxidizer are discussed. Kennedy Space Center developments in N2O4 control for the space shuttle are featured. Other areas covered are life support equipment and transportation.

  14. Regulation of Nitrogen Metabolism by GATA Zinc Finger Transcription Factors in Yarrowia lipolytica

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pomraning, Kyle R.; Bredeweg, Erin L.; Baker, Scott E.

    ABSTRACT Fungi accumulate lipids in a manner dependent on the quantity and quality of the nitrogen source on which they are growing. In the oleaginous yeastYarrowia lipolytica, growth on a complex source of nitrogen enables rapid growth and limited accumulation of neutral lipids, while growth on a simple nitrogen source promotes lipid accumulation in large lipid droplets. Here we examined the roles of nitrogen catabolite repression and its regulation by GATA zinc finger transcription factors on lipid metabolism inY. lipolytica. Deletion of the GATA transcription factor genesgzf3andgzf2resulted in nitrogen source-specific growth defects and greater accumulation of lipids when the cells weremore » growing on a simple nitrogen source. Deletion ofgzf1, which is most similar to activators of genes repressed by nitrogen catabolite repression in filamentous ascomycetes, did not affect growth on the nitrogen sources tested. We examined gene expression of wild-type and GATA transcription factor mutants on simple and complex nitrogen sources and found that expression of enzymes involved in malate metabolism, beta-oxidation, and ammonia utilization are strongly upregulated on a simple nitrogen source. Deletion ofgzf3results in overexpression of genes with GATAA sites in their promoters, suggesting that it acts as a repressor, whilegzf2is required for expression of ammonia utilization genes but does not grossly affect the transcription level of genes predicted to be controlled by nitrogen catabolite repression. Both GATA transcription factor mutants exhibit decreased expression of genes controlled by carbon catabolite repression via the repressormig1, including genes for beta-oxidation, highlighting the complex interplay between regulation of carbon, nitrogen, and lipid metabolism. IMPORTANCENitrogen source is commonly used to control lipid production in industrial fungi. Here we identified regulators of nitrogen catabolite repression in the oleaginous yeastY. lipolyticato determine how the nitrogen source regulates lipid metabolism. We show that disruption of both activators and repressors of nitrogen catabolite repression leads to increased lipid accumulation via activation of carbon catabolite repression through an as yet uncharacterized method.« less

  15. Nitrogen Doped Graphene Supported Pt Nanoflowers as Electrocatalysts for Oxidation of Formaldehyde.

    PubMed

    Xie, Aijuan; Zhou, Wenting; Luo, Shiping; Chen, Yu; Zhou, Xiaoqing; Chao, Yao

    2017-02-01

    A facile Pt nanoflowers/nitrogen-doped graphene (PtNFs/NG) electrocatalyst was prepared via depositing Pt nanoflowers (PtNFs) onto the nitrogen-doped graphene (NG) matrix with urea as the nitrogen source and PtNFs/NG modified glassy carbon electrode (GCE) was prepared by electro-chemical method. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman spectroscope, X-ray photoelectron spectroscopy (XPS) and Scanning electron microscope (SEM) were used to characterize the resulting composites. Also oxidation of formaldehyde on the resulting PtNFs/NG modified electrode was investigated. The influence of deposition time, electrodeposition potential and formaldehyde concentration on electrooxidation of formaldehyde was detected, the experimental results indicate the high performance of PtNFs/NG catalyst for formaldehyde oxidation is at electrodeposition time of 300 s with the applied potential of −0.3 V. Electrochemical process, electrocatalytic stability and chronoamperometry were also inspected, it was indicated that formalde-hyde oxidation reaction on the PtNFs/NG electrode is diffusion-controlled and PtNFs/NG exhibits a high catalytic activity, stability as well as excellent poisoning-tolerance towards formaldehyde oxidation, which is attributed to the synergistic effect of PtNFs and NG. It turns out that PtNFs/NG can be used in direct liquid-feed fuel cells as a promising alternative catalyst.

  16. 40 CFR 86.1323-2007 - Oxides of nitrogen analyzer calibration.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 19 2011-07-01 2011-07-01 false Oxides of nitrogen analyzer... Exhaust Test Procedures § 86.1323-2007 Oxides of nitrogen analyzer calibration. This section describes the initial and periodic calibration of the chemiluminescent oxides of nitrogen analyzer. (a) Prior to...

  17. 40 CFR 86.1323-2007 - Oxides of nitrogen analyzer calibration.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Oxides of nitrogen analyzer... Exhaust Test Procedures § 86.1323-2007 Oxides of nitrogen analyzer calibration. This section describes the initial and periodic calibration of the chemiluminescent oxides of nitrogen analyzer. (a) Prior to...

  18. 40 CFR 86.1323-2007 - Oxides of nitrogen analyzer calibration.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 20 2013-07-01 2013-07-01 false Oxides of nitrogen analyzer... Exhaust Test Procedures § 86.1323-2007 Oxides of nitrogen analyzer calibration. This section describes the initial and periodic calibration of the chemiluminescent oxides of nitrogen analyzer. (a) Prior to...

  19. 40 CFR 86.1323-2007 - Oxides of nitrogen analyzer calibration.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 20 2012-07-01 2012-07-01 false Oxides of nitrogen analyzer... Exhaust Test Procedures § 86.1323-2007 Oxides of nitrogen analyzer calibration. This section describes the initial and periodic calibration of the chemiluminescent oxides of nitrogen analyzer. (a) Prior to...

  20. 40 CFR 89.112 - Oxides of nitrogen, carbon monoxide, hydrocarbon, and particulate matter exhaust emission standards.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Oxides of nitrogen, carbon monoxide....112 Oxides of nitrogen, carbon monoxide, hydrocarbon, and particulate matter exhaust emission... emissions of oxides of nitrogen, carbon monoxide, hydrocarbon, and nonmethane hydrocarbon are measured using...

  1. 40 CFR 89.112 - Oxides of nitrogen, carbon monoxide, hydrocarbon, and particulate matter exhaust emission standards.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Oxides of nitrogen, carbon monoxide....112 Oxides of nitrogen, carbon monoxide, hydrocarbon, and particulate matter exhaust emission... emissions of oxides of nitrogen, carbon monoxide, hydrocarbon, and nonmethane hydrocarbon are measured using...

  2. 40 CFR 89.112 - Oxides of nitrogen, carbon monoxide, hydrocarbon, and particulate matter exhaust emission standards.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Oxides of nitrogen, carbon monoxide....112 Oxides of nitrogen, carbon monoxide, hydrocarbon, and particulate matter exhaust emission... emissions of oxides of nitrogen, carbon monoxide, hydrocarbon, and nonmethane hydrocarbon are measured using...

  3. Correlation of black smoke and nitrogen oxides emissions through field testing of in-use diesel vehicles.

    PubMed

    Lin, Cherng-Yuan; Chen, Lih-Wei; Wang, Li-Ting

    2006-05-01

    Diesel vehicles are one of the major forms of transportation, especially in metropolitan regions. However, air pollution released from diesel vehicles causes serious damage to both human health and the environment, and as a result is of great public concern. Nitrogen oxides and black smoke are two significant emissions from diesel engines. Understanding the correlation between these two emissions is an important step toward developing the technology for an appropriate strategy to control or eliminate them. This study field-tested 185 diesel vehicles at an engine dynamometer station for their black smoke reflectivity and nitrogen oxides concentration to explore the correlation between these two pollutants. The test results revealed that most of the tested diesel vehicles emitted black smoke with low reflectivity and produced low nitrogen oxides concentration. The age of the tested vehicles has a significant influence on the NOx emission. The older the tested vehicles, the higher the NOx concentrations emitted, however, there was no obvious correlation between the age of the tested diesel vehicles and the black smoke reflectivity. In addition, if the make and engine displacement volume of the tested diesel vehicles are not taken into consideration, then the correlation between the black smoke reflectivity and nitrogen oxides emission weakens. However, when the tested vehicles were classified into various groups based on their makes and engine displacement volumes, then the make of a tested vehicle became a dominant factor for both the quantity and the trend of the black smoke reflectivity, as well as the NOx emission. Higher emission indices of black smoke reflectivity and nitrogen oxides were observed if the diesel vehicles were operated at low engine speed and full engine load conditions. Moreover, the larger the displacement volume of the engine of the tested vehicle, the lower the emission indices of both black smoke reflectivity and nitrogen oxides emitted. The emission indices of black smokes reflectivity and nitrogen oxides emission of the tested diesel vehicles were also influenced by the make of the vehicle. It was observed that the emission indices of black smoke reflectivity decreased nearly linearly with the increase of the emission indices of NOx for the tested vehicles belonging to the same group of make and engine displacement volume.

  4. [Physiocochemical properties of blood serum proteins of coal miners].

    PubMed

    Nandakova, V N; Zemliakova, L F; Sukhanov, V V; Min'ko, L A

    1979-01-01

    Using disk electrophoresis in the polyacrylamide gel, blood serum proteins were studied in miners working under conditions of the combine (the control group) and drilling-and-blasting (the contact with carbon oxide, nitrogen oxides) driving technique under normal temperature conditions. 26--27 protein fractions characterized by mobility, thermolability under definite conditions of the experiment and the contitative content were obtained. It is shown that the contact with carbon oxide and nitrogen oxides causes changes in the rpoperties of certain proteins (II3, globulins--2 alpha 1, 3 alpha 1, 2 beta, 2 alpha 2, 5 alpha 2, 6 alpha 2, 7 alpha 2) of miners blood serum. Some of these proteins are supposed to participate in the adaptation reactions of the organism.

  5. Structural aspects of denitrifying enzymes.

    PubMed

    Moura, I; Moura, J J

    2001-04-01

    The reduction of nitrate to nitrogen gas via nitrite, nitric oxide and nitrous oxide is the metabolic pathway usually known as denitrification, a key step in the nitrogen cycle. As observed for other elemental cycles, a battery of enzymes are utilized, namely the reductases for nitrate, nitrite, nitric oxide and nitrous oxide, as well as multiple electron donors that interact with these enzymes, in order to carry out the stepwise reactions that involve key intermediates. Because of the importance of this pathway (of parallel importance to the nitrogen-fixation pathway), efforts are underway to understand the structures of the participating enzymes and to uncover mechanistic aspects. Three-dimensional structures have been solved for the majority of these enzymes in the past few years, revealing the architecture of the active metal sites as well as global structural aspects, and possible mechanistic aspects. In addition, the recognition of specific electron-transfer partners raises important questions regarding specific electron-transfer pathways, partner recognition and control of metabolism.

  6. Three Dimensional Nitrogen-Doped and Nitrogen, Sulfur-Codoped Graphene Hydrogels for Electrode Materials in Supercapacitors.

    PubMed

    Yuan, Zhao; Qiao, Fei; Wang, Guiqiang; Zhou, Jin; Cui, Hongyou; Zhuo, Shuping; Xing, Ling-Bao

    2018-08-01

    In present work, reduced graphene oxide hydrogels (RGOHs) with three-dimensional (3D) porous structure are prepared through chemical reduction method by using aminourea (NRGOHs) and aminothiourea (NSRGOHs) as reductants. The as-prepared RGOHs are considered not only as promising electrode materials for supercapacitors, but also the doping of nitrogen (aminourea, NRGOHs) or nitrogen/sulfur (aminothiourea, NSRGOHs) can improve electrochemical performance through faradaic pseudocapacitance. The optimized samples have been prepared by controlling the mass ratios of graphene oxide (GO) to aminourea or aminothiourea to be 1:1, 1:2 and 1:5, respectively. With adding different amounts of aminourea or aminothiourea, the obtained RGOHs exhibited different electrochemical performance in supercapacitors. With increasing the dosage of the reductants, the RGOHs revealed better specific capacitances. Moreover, NSRGOHs with nitrogen, sulfur-codoping exhibited better capacitance performance than that of NRGOHs with only nitrogen-doping. NSRGOHs showed excellent capacitive performance with a very high specific capacitance up to 232.2, 323.3 and 345.6 F g-1 at 0.2 A g-1, while NRGOHs showed capacitive performance with specific capacitance up to 220.6, 306.5 and 332.7 F g-1 at 0.2 A g-1. This provides a strategy to improve the capacitive properties of RGOHs significantly by controlling different doping the materials.

  7. 40 CFR 62.2350 - Identification of plan.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... sulfuric acid production units, submitted on December 14, 1978. (2) Control of total reduced sulfur (TRS... is June 1, 1990. (5) Control of metals, acid gases, organic compounds and nitrogen oxide emissions...

  8. Technology innovations and experience curves for nitrogen oxides control technologies.

    PubMed

    Yeh, Sonia; Rubin, Edward S; Taylor, Margaret R; Hounshell, David A

    2005-12-01

    This paper reviews the regulatory history for nitrogen oxides (NOx) pollutant emissions from stationary sources, primarily in coal-fired power plants. Nitrogen dioxide (NO2) is one of the six criteria pollutants regulated by the 1970 Clean Air Act where National Ambient Air Quality Standards were established to protect public health and welfare. We use patent data to show that in the cases of Japan, Germany, and the United States, innovations in NOx control technologies did not occur until stringent government regulations were in place, thus "forcing" innovation. We also demonstrate that reductions in the capital and operation and maintenance (O&M) costs of new generations of high-efficiency NOx control technologies, selective catalytic reduction (SCR), are consistently associated with the increasing adoption of the control technology: the so-called learning-by-doing phenomena. The results show that as cumulative world coal-fired SCR capacity doubles, capital costs decline to approximately 86% and O&M costs to 58% of their original values. The observed changes in SCR technology reflect the impact of technological advance as well as other factors, such as market competition and economies of scale.

  9. 40 CFR 86.332-79 - Oxides of nitrogen analyzer calibration.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 19 2013-07-01 2013-07-01 false Oxides of nitrogen analyzer... Procedures § 86.332-79 Oxides of nitrogen analyzer calibration. (a) At least monthly during testing, perform.... (2) Zero the oxides of nitrogen analyzer. (3) Connect the outlet of the NOX generator (see Figure D79...

  10. 40 CFR 92.121 - Oxides of nitrogen analyzer calibration and check.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Oxides of nitrogen analyzer... Procedures § 92.121 Oxides of nitrogen analyzer calibration and check. (a) Quench checks; NO X analyzer. (1... performed in step in paragraph (a)(3)(i) this section. (b) Oxides of nitrogen analyzer calibration. (1...

  11. 40 CFR 92.121 - Oxides of nitrogen analyzer calibration and check.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Oxides of nitrogen analyzer calibration... Procedures § 92.121 Oxides of nitrogen analyzer calibration and check. (a) Quench checks; NO X analyzer. (1... performed in step in paragraph (a)(3)(i) this section. (b) Oxides of nitrogen analyzer calibration. (1...

  12. 40 CFR 86.332-79 - Oxides of nitrogen analyzer calibration.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Oxides of nitrogen analyzer... Procedures § 86.332-79 Oxides of nitrogen analyzer calibration. (a) At least monthly during testing, perform.... (2) Zero the oxides of nitrogen analyzer. (3) Connect the outlet of the NOX generator (see Figure D79...

  13. 40 CFR 92.121 - Oxides of nitrogen analyzer calibration and check.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Oxides of nitrogen analyzer... Procedures § 92.121 Oxides of nitrogen analyzer calibration and check. (a) Quench checks; NO X analyzer. (1... performed in step in paragraph (a)(3)(i) this section. (b) Oxides of nitrogen analyzer calibration. (1...

  14. 40 CFR 92.121 - Oxides of nitrogen analyzer calibration and check.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Oxides of nitrogen analyzer... Procedures § 92.121 Oxides of nitrogen analyzer calibration and check. (a) Quench checks; NO X analyzer. (1... performed in step in paragraph (a)(3)(i) this section. (b) Oxides of nitrogen analyzer calibration. (1...

  15. 40 CFR 52.1890 - Removed control measures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... trading program, etc.) affecting large fossil-fueled utility and industrial boilers. OAC 3745-23-06, Control of nitrogen oxide emissions from stationary sources, also known as AP-7-06 in its original form...

  16. 40 CFR 52.1890 - Removed control measures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... trading program, etc.) affecting large fossil-fueled utility and industrial boilers. OAC 3745-23-06, Control of nitrogen oxide emissions from stationary sources, also known as AP-7-06 in its original form...

  17. 40 CFR 52.1890 - Removed control measures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... trading program, etc.) affecting large fossil-fueled utility and industrial boilers. OAC 3745-23-06, Control of nitrogen oxide emissions from stationary sources, also known as AP-7-06 in its original form...

  18. 40 CFR 52.1890 - Removed control measures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... trading program, etc.) affecting large fossil-fueled utility and industrial boilers. OAC 3745-23-06, Control of nitrogen oxide emissions from stationary sources, also known as AP-7-06 in its original form...

  19. 40 CFR 52.1890 - Removed control measures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... trading program, etc.) affecting large fossil-fueled utility and industrial boilers. OAC 3745-23-06, Control of nitrogen oxide emissions from stationary sources, also known as AP-7-06 in its original form...

  20. Abrupt recent trend changes in atmospheric nitrogen dioxide over the Middle East

    PubMed Central

    Lelieveld, Jos; Beirle, Steffen; Hörmann, Christoph; Stenchikov, Georgiy; Wagner, Thomas

    2015-01-01

    Nitrogen oxides, released from fossil fuel use and other combustion processes, affect air quality and climate. From the mid-1990s onward, nitrogen dioxide (NO2) has been monitored from space, and since 2004 with relatively high spatial resolution by the Ozone Monitoring Instrument. Strong upward NO2 trends have been observed over South and East Asia and the Middle East, in particular over major cities. We show, however, that a combination of air quality control and political factors, including economical crisis and armed conflict, has drastically altered the emission landscape of nitrogen oxides in the Middle East. Large changes, including trend reversals, have occurred since about 2010 that could not have been predicted and therefore are at odds with emission scenarios used in projections of air pollution and climate change in the early 21st century. PMID:26601240

  1. MULTIPOLLUTANT EMISSION CONTROL TECHNOLOGY OPTIONS FOR COAL-FIRED POWER PLANTS

    EPA Science Inventory

    The report presents and analyzes various existing and novel control technologies designed to achieve multipollutant [sulfur dioxide (SO2), nitrogen oxide (NOX), and mercury (Hg)] emission reductions. Summary descriptions are included of 23 multipollutant control technologies that...

  2. ENVIRONMENTAL TECHNOLOGY VERIFICATION: ADD-ON NOX CONTROLS

    EPA Science Inventory

    The paper discusses the environmental technology verification (ETV) of add-on nitrogen oxide (NOx) controls. Research Triangle Institute (RTI) is EPA's cooperating partner for the Air Pollution Control Technology (APCT) Program, one of a dozen ETV pilot programs. Verification of ...

  3. Effect of oxygen plasma and thermal oxidation on shallow nitrogen-vacancy centers in diamond

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kim, M.; Rugar, D., E-mail: rugar@us.ibm.com; Center for Probing the Nanoscale, Stanford University, Stanford, California 94305

    2014-07-28

    We investigate the effect of two different surface treatments on shallow nitrogen-vacancy (NV) centers in diamond. Short duration oxygen plasma exposure is found to damage near-surface NV centers, resulting in their disappearance in fluorescence images. Subsequent annealing creates large numbers of new NV centers, attributed to plasma-induced vacancy creation. By tracking individual NV centers during thermal oxidation, we show that oxidation at 550 °C results in modest improvement of spin coherence. Higher temperature oxidations correlate with gradual decline in spin coherence and eventual instability of NV centers before ultimate disappearance. This is indicative of a reduction of the NV-to-surface distance duemore » to oxidative etching. Thermal oxidation can offer controlled access to near-surface NV spins at the nanometer scale, an important requirement for many applications of NV-based nanomagnetometry.« less

  4. The development and application of SCR denitrification technology in power plant

    NASA Astrophysics Data System (ADS)

    Wu, Junnan

    2017-12-01

    In recent decades, the emission of the nitrogen oxides (NOX) has been increasing with the years of the thermal power plant. The environment pollution caused by the emission of quantities of nitrogen oxides became more and more serious, so people now put more emphasis on the control of the emission of the nitrogen oxides. Especially, our country and the society are paying much more attention to the environment protection and the environment problems cannot be neglected. In this paper, we introduced the related research background of the technology of SCR denitrification which was as the symbol of the technology of the catalytic denitrification and discussed the reaction principles of the SCR denitrification and frequently used catalysts, the process of the technology, and the configuration. In the end, we pointed the way of the future research of the technology of the SCR denitrification.

  5. Biofilter for removal of nitrogen oxides from contaminated gases under aerobic conditions

    DOEpatents

    Apel, William A.

    1998-01-01

    A biofilter for reducing concentrations of gaseous nitrogen oxides in a polluted gas comprises a porous organic filter bed medium disposed in a housing, the filter bed medium including a mixed culture of naturally occurring denitrifying bacteria for converting the nitrogen oxides to nitrogen gas, carbon dioxide, and water. A method of reducing concentrations of nitrogen oxides in polluted gas comprises conducting the polluted gas through the biofilter so that the denitrifying bacteria can degrade the nitrogen oxides. A preferred filter medium is wood compost, however composts of other organic materials are functional. Regulation of pH, moisture content, exogenous carbon sources, and temperature are described.

  6. ROLE OF NITROGEN OXIDES IN NONURBAN OZONE FORMATION IN THE PLANETARY BOUNDARY LAYER OVER N (NORTH) AMERICA, W (WESTERN) EUROPE AND ADJACENT AREAS OF OCEAN

    EPA Science Inventory

    The status of knowledge on photochemical ozone formation and the effects of nitrogen oxides and peroxyacyl nitrates on such formation has been evaluated. The literature is reviewed on nonurban ozone and nitrogen oxide concentration distributions, ozone lifetimes, nitrogen oxide l...

  7. 40 CFR 60.55a - Standard for nitrogen oxides.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standard for nitrogen oxides. 60.55a... § 60.55a Standard for nitrogen oxides. On and after the date on which the initial compliance test is... gases that contain nitrogen oxides in excess of 180 parts per million by volume, corrected to 7 percent...

  8. 40 CFR Table 2 to Subpart Fff of... - Nitrogen Oxides Requirements for Affected Facilities

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 8 2011-07-01 2011-07-01 false Nitrogen Oxides Requirements for... Before September 20, 1994 Pt. 62, Subpt. FFF, Table 2 Table 2 to Subpart FFF of Part 62—Nitrogen Oxides Requirements for Affected Facilities Municipal waste combustor technology Nitrogen oxides emission limit (parts...

  9. 40 CFR Table 1 to Subpart Cb of... - Nitrogen Oxides Guidelines for Designated Facilities

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Nitrogen Oxides Guidelines for... September 20, 1994 Pt. 60, Subpt. Cb, Table 1 Table 1 to Subpart Cb of part 60—Nitrogen Oxides Guidelines for Designated Facilities Municipal waste combustor technology Before April 28, 2009,nitrogen oxides...

  10. 40 CFR 60.52b - Standards for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... metals, acid gases, organics, and nitrogen oxides. 60.52b Section 60.52b Protection of Environment... § 60.52b Standards for municipal waste combustor metals, acid gases, organics, and nitrogen oxides. (a... (total mass), corrected to 7 percent oxygen. (d) The limits for nitrogen oxides are specified in...

  11. 40 CFR Table 2 to Subpart Fff of... - Nitrogen Oxides Requirements for Affected Facilities

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 9 2014-07-01 2014-07-01 false Nitrogen Oxides Requirements for... Before September 20, 1994 Pt. 62, Subpt. FFF, Table 2 Table 2 to Subpart FFF of Part 62—Nitrogen Oxides Requirements for Affected Facilities Municipal waste combustor technology Nitrogen oxides emission limit (parts...

  12. 40 CFR 60.52b - Standards for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... metals, acid gases, organics, and nitrogen oxides. 60.52b Section 60.52b Protection of Environment... § 60.52b Standards for municipal waste combustor metals, acid gases, organics, and nitrogen oxides. (a... (total mass), corrected to 7 percent oxygen. (d) The limits for nitrogen oxides are specified in...

  13. 40 CFR 60.52b - Standards for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... metals, acid gases, organics, and nitrogen oxides. 60.52b Section 60.52b Protection of Environment... § 60.52b Standards for municipal waste combustor metals, acid gases, organics, and nitrogen oxides. (a... (total mass), corrected to 7 percent oxygen. (d) The limits for nitrogen oxides are specified in...

  14. 40 CFR 60.55a - Standard for nitrogen oxides.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standard for nitrogen oxides. 60.55a... § 60.55a Standard for nitrogen oxides. On and after the date on which the initial compliance test is... gases that contain nitrogen oxides in excess of 180 parts per million by volume, corrected to 7 percent...

  15. 40 CFR 60.52b - Standards for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... metals, acid gases, organics, and nitrogen oxides. 60.52b Section 60.52b Protection of Environment... § 60.52b Standards for municipal waste combustor metals, acid gases, organics, and nitrogen oxides. (a... (total mass), corrected to 7 percent oxygen. (d) The limits for nitrogen oxides are specified in...

  16. 40 CFR Table 2 to Subpart Fff of... - Nitrogen Oxides Requirements for Affected Facilities

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 9 2012-07-01 2012-07-01 false Nitrogen Oxides Requirements for... Before September 20, 1994 Pt. 62, Subpt. FFF, Table 2 Table 2 to Subpart FFF of Part 62—Nitrogen Oxides Requirements for Affected Facilities Municipal waste combustor technology Nitrogen oxides emission limit (parts...

  17. 40 CFR Table 2 to Subpart Fff of... - Nitrogen Oxides Requirements for Affected Facilities

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 9 2013-07-01 2013-07-01 false Nitrogen Oxides Requirements for... Before September 20, 1994 Pt. 62, Subpt. FFF, Table 2 Table 2 to Subpart FFF of Part 62—Nitrogen Oxides Requirements for Affected Facilities Municipal waste combustor technology Nitrogen oxides emission limit (parts...

  18. 40 CFR 60.55a - Standard for nitrogen oxides.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standard for nitrogen oxides. 60.55a... § 60.55a Standard for nitrogen oxides. On and after the date on which the initial compliance test is... gases that contain nitrogen oxides in excess of 180 parts per million by volume, corrected to 7 percent...

  19. 40 CFR Table 1 to Subpart Cb of... - Nitrogen Oxides Guidelines for Designated Facilities

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Nitrogen Oxides Guidelines for... September 20, 1994 Pt. 60, Subpt. Cb, Table 1 Table 1 to Subpart Cb of Part 60—Nitrogen Oxides Guidelines for Designated Facilities Municipal waste combustor technology Before April 28, 2009,nitrogen oxides...

  20. 40 CFR 60.55a - Standard for nitrogen oxides.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standard for nitrogen oxides. 60.55a... § 60.55a Standard for nitrogen oxides. On and after the date on which the initial compliance test is... gases that contain nitrogen oxides in excess of 180 parts per million by volume, corrected to 7 percent...

  1. Proteome analysis of yeast response to various nutrient limitations

    PubMed Central

    Kolkman, Annemieke; Daran-Lapujade, Pascale; Fullaondo, Asier; Olsthoorn, Maurien M A; Pronk, Jack T; Slijper, Monique; Heck, Albert J R

    2006-01-01

    We compared the response of Saccharomyces cerevisiae to carbon (glucose) and nitrogen (ammonia) limitation in chemostat cultivation at the proteome level. Protein levels were differentially quantified using unlabeled and 15N metabolically labeled yeast cultures. A total of 928 proteins covering a wide range of isoelectric points, molecular weights and subcellular localizations were identified. Stringent statistical analysis identified 51 proteins upregulated in response to glucose limitation and 51 upregulated in response to ammonia limitation. Under glucose limitation, typical glucose-repressed genes encoding proteins involved in alternative carbon source utilization, fatty acids β-oxidation and oxidative phosphorylation displayed an increased protein level. Proteins upregulated in response to nitrogen limitation were mostly involved in scavenging of alternative nitrogen sources and protein degradation. Comparison of transcript and protein levels clearly showed that upregulation in response to glucose limitation was mainly transcriptionally controlled, whereas upregulation in response to nitrogen limitation was essentially controlled at the post-transcriptional level by increased translational efficiency and/or decreased protein degradation. These observations underline the need for multilevel analysis in yeast systems biology. PMID:16738570

  2. NATURAL EMISSIONS OF NON-METHANE VOLATILE ORGANIC COMPOUNDS, CARBON MONOXIDE, AND OXIDES OF NITROGEN FROM NORTH AMERICA

    EPA Science Inventory

    The magnitudes, distributions, controlling processes and uncertainties associated with North American natural emissions of oxidant precursors are reviewed. Natural emissions are repsonsible for a major portion of the compounds, including non-methane volatile organic compounds (N...

  3. Denitrification of combustion gases. [Patent application

    DOEpatents

    Yang, R.T.

    1980-10-09

    A method for treating waste combustion gas to remove the nitrogen oxygen gases therefrom is disclosed wherein the waste gas is first contacted with calcium oxide which absorbs and chemically reacts with the nitrogen oxide gases therein at a temperature from about 100/sup 0/ to 430/sup 0/C. The thus reacted calcium oxide (now calcium nitrate) is then heated at a temperature range between about 430/sup 0/ and 900/sup 0/C, resulting in regeneration of the calcium oxide and production of the decomposition gas composed of nitrogen and nitrogen oxide gas. The decomposition gases can be recycled to the calcium oxide contacting step to minimize the amount of nitrogen oxide gases in the final product gas.

  4. Modeling reactive nitrogen in North America: recent ...

    EPA Pesticide Factsheets

    Nitrogen is an essential building block of all proteins and thus an essential nutrient for all life. The bulk of nitrogen in the environment is tightly bound as non-reactive N2. Reactive nitrogen, which is naturally produced via enzymatic reactions, forest fires and lightning, is continually recycled and cascades through air, water, and soil media (Galloway et al., 2003). Human activity has perturbed this cycle through the combustion of fossil fuels and synthesis of fertilizers. The anthropogenic contribution to this cycle is now larger than natural sources in the United States and globally (Galloway et al., 2004). Reactive nitrogen enters the biosphere primarily from emissions of oxidized nitrogen to the atmosphere from combustion sources, as inorganic fertilizer applied to crops as reduced nitrogen fixed from atmospheric N2 through the Haber-Bosch process, as organic fertilizers such as manure, and through the cultivation of nitrogen fixing crops (Canfield et al., 2010). Both the United States (US) Clean Air Act and the Canadian Environmental Protection Act (CEPA) have substantially reduced the emissions of oxidized nitrogen in North America through NOx controls on smokestacks and exhaust pipes (Sickles and Shadwick, 2015; AQA, 2015). However, reduced nitrogen emissions have remained constant during the last few decades of emission reductions. The National Exposure Research Laboratory’s Atmospheric Modeling Division (AMAD) c

  5. Nano-scale investigation of the association of microbial nitrogen residues with iron (hydr)oxides in a forest soil O-horizon

    Treesearch

    M. Keiluweit; J.J. Bougoure; L. Zeglin; D.D. Myrold; P.K. Weber; J. Pett-Ridge; M. Kleber; P.S. Nico

    2012-01-01

    Amino sugars in fungal cell walls (such as chitin) represent an important source of nitrogen (N) in many forest soil ecosystems. Despite the importance of this material in soil nitrogen cycling, comparatively little is known about abiotic and biotic controls on and the timescale of its turnover. Part of the reason for this lack of information is the inaccessibility of...

  6. 40 CFR 50.11 - National primary and secondary ambient air quality standards for oxides of nitrogen (with...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 2 2011-07-01 2011-07-01 false National primary and secondary ambient air quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). 50.11 Section... quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). (a) The level of the...

  7. 40 CFR 50.11 - National primary and secondary ambient air quality standards for oxides of nitrogen (with...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 2 2010-07-01 2010-07-01 false National primary and secondary ambient air quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). 50.11 Section... quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). (a) The level of the...

  8. 40 CFR 60.72 - Standard for nitrogen oxides.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for nitrogen oxides. 60.72... Plants § 60.72 Standard for nitrogen oxides. (a) On and after the date on which the performance test...) Contain nitrogen oxides, expressed as NO2, in excess of 1.5 kg per metric ton of acid produced (3.0 lb per...

  9. 40 CFR 60.72 - Standard for nitrogen oxides.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standard for nitrogen oxides. 60.72... Plants § 60.72 Standard for nitrogen oxides. (a) On and after the date on which the performance test...) Contain nitrogen oxides, expressed as NO2, in excess of 1.5 kg per metric ton of acid produced (3.0 lb per...

  10. 40 CFR 60.33b - Emission guidelines for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... combustor metals, acid gases, organics, and nitrogen oxides. 60.33b Section 60.33b Protection of Environment..., acid gases, organics, and nitrogen oxides. (a) The emission limits for municipal waste combustor metals... oxygen. (d) For approval, a State plan shall include emission limits for nitrogen oxides at least as...

  11. 40 CFR 60.33b - Emission guidelines for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... combustor metals, acid gases, organics, and nitrogen oxides. 60.33b Section 60.33b Protection of Environment..., acid gases, organics, and nitrogen oxides. (a) The emission limits for municipal waste combustor metals... oxygen. (d) For approval, a State plan shall include emission limits for nitrogen oxides at least as...

  12. 40 CFR 60.72 - Standard for nitrogen oxides.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standard for nitrogen oxides. 60.72... Plants § 60.72 Standard for nitrogen oxides. (a) On and after the date on which the performance test...) Contain nitrogen oxides, expressed as NO2, in excess of 1.5 kg per metric ton of acid produced (3.0 lb per...

  13. 40 CFR 60.72 - Standard for nitrogen oxides.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standard for nitrogen oxides. 60.72... Plants § 60.72 Standard for nitrogen oxides. (a) On and after the date on which the performance test...) Contain nitrogen oxides, expressed as NO2, in excess of 1.5 kg per metric ton of acid produced (3.0 lb per...

  14. 40 CFR 60.33b - Emission guidelines for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... combustor metals, acid gases, organics, and nitrogen oxides. 60.33b Section 60.33b Protection of Environment..., acid gases, organics, and nitrogen oxides. (a) The emission limits for municipal waste combustor metals... oxygen. (d) For approval, a State plan shall include emission limits for nitrogen oxides at least as...

  15. 40 CFR 60.33b - Emission guidelines for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... combustor metals, acid gases, organics, and nitrogen oxides. 60.33b Section 60.33b Protection of Environment..., acid gases, organics, and nitrogen oxides. (a) The emission limits for municipal waste combustor metals... oxygen. (d) For approval, a State plan shall include emission limits for nitrogen oxides at least as...

  16. A Spatial Panel Data Analysis of Economic Growth, Urbanization, and NOx Emissions in China

    PubMed Central

    Ge, Xiangyu; Zhou, Yanli; Liu, Songlin

    2018-01-01

    Is nitrogen oxides emissions spatially correlated in a Chinese context? What is the relationship between nitrogen oxides emission levels and fast-growing economy/urbanization? More importantly, what environmental preservation and economic developing policies should China’s central and local governments take to mitigate the overall nitrogen oxides emissions and prevent severe air pollution at the provincial level in specific locations and their neighboring areas? The present study aims to tackle these issues. This is the first research that simultaneously studies the nexus between nitrogen oxides emissions and economic development/urbanization, with the application of a spatial panel data technique. Our empirical findings suggest that spatial dependence of nitrogen oxides emissions distribution exists at the provincial level. Through the investigation of the existence of an environmental Kuznets curve (EKC) embedded within the Stochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) framework, we conclude something interesting: an inverse N-shaped EKC describes both the income-nitrogen oxides nexus and the urbanization-nitrogen oxides nexus. Some well-directed policy advice is provided to reduce nitrogen oxides in the future. Moreover, these results contribute to the literature on development and pollution. PMID:29641500

  17. A Spatial Panel Data Analysis of Economic Growth, Urbanization, and NOx Emissions in China.

    PubMed

    Ge, Xiangyu; Zhou, Zhimin; Zhou, Yanli; Ye, Xinyue; Liu, Songlin

    2018-04-11

    Abstract : Is nitrogen oxides emissions spatially correlated in a Chinese context? What is the relationship between nitrogen oxides emission levels and fast-growing economy/urbanization? More importantly, what environmental preservation and economic developing policies should China's central and local governments take to mitigate the overall nitrogen oxides emissions and prevent severe air pollution at the provincial level in specific locations and their neighboring areas? The present study aims to tackle these issues. This is the first research that simultaneously studies the nexus between nitrogen oxides emissions and economic development/urbanization, with the application of a spatial panel data technique. Our empirical findings suggest that spatial dependence of nitrogen oxides emissions distribution exists at the provincial level. Through the investigation of the existence of an environmental Kuznets curve (EKC) embedded within the Stochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) framework, we conclude something interesting: an inverse N-shaped EKC describes both the income-nitrogen oxides nexus and the urbanization-nitrogen oxides nexus. Some well-directed policy advice is provided to reduce nitrogen oxides in the future. Moreover, these results contribute to the literature on development and pollution.

  18. Air Quality Criteria for Oxides of Nitrogen (Final Report, 1993)

    EPA Science Inventory

    This criteria document focuses on a review and assessment of the effects on human health and welfare of the nitrogen oxides, nitric oxide (NO) and nitrogen dioxide (NO2), and the related compounds, nitrites, nitrates, nitrogenous acids, and nitrosamines. Although the emphasis is ...

  19. Biofilter for removal of nitrogen oxides from contaminated gases under aerobic conditions

    DOEpatents

    Apel, W.A.

    1998-08-18

    A biofilter is described for reducing concentrations of gaseous nitrogen oxides in a polluted gas comprises a porous organic filter bed medium disposed in a housing, the filter bed medium including a mixed culture of naturally occurring denitrifying bacteria for converting the nitrogen oxides to nitrogen gas, carbon dioxide, and water. A method is described of reducing concentrations of nitrogen oxides in polluted gas comprises conducting the polluted gas through the biofilter so that the denitrifying bacteria can degrade the nitrogen oxides. A preferred filter medium is wood compost, however composts of other organic materials are functional. Regulation of pH, moisture content, exogenous carbon sources, and temperature are described. 6 figs.

  20. Apollo 16 Mission: Oxidizer Deservicing Tank Failure. No. 1; Anomaly Report

    NASA Technical Reports Server (NTRS)

    1972-01-01

    An explosive failure of a ground support equipment decontamination unit tank occurred during the postflight deactivation of the oxidizer (nitrogen tetroxide) portion of the Apollo 16 command module reaction control system. A discussion of the significant aspects of the incident and conclusions are included.

  1. The Pkn22 Ser/Thr kinase in Nostoc PCC 7120: role of FurA and NtcA regulators and transcript profiling under nitrogen starvation and oxidative stress.

    PubMed

    Yingping, Fan; Lemeille, Sylvain; González, Andrés; Risoul, Véronique; Denis, Yann; Richaud, Pierre; Lamrabet, Otmane; Fillat, Maria F; Zhang, Cheng-Cai; Latifi, Amel

    2015-07-29

    The filamentous cyanobacterium Nostoc sp. strain PCC 7120 can fix N2 when combined nitrogen is not available. Furthermore, it has to cope with reactive oxygen species generated as byproducts of photosynthesis and respiration. We have previously demonstrated the synthesis of Ser/Thr kinase Pkn22 as an important survival response of Nostoc to oxidative damage. In this study we wished to investigate the possible involvement of this kinase in signalling peroxide stress and nitrogen deprivation. Quantitative RT-PCR experiments revealed that the pkn22 gene is induced in response to peroxide stress and to combined nitrogen starvation. Electrophoretic motility assays indicated that the pkn22 promoter is recognized by the global transcriptional regulators FurA and NtcA. Transcriptomic analysis comparing a pkn22-insertion mutant and the wild type strain indicated that this kinase regulates genes involved in important cellular functions such as photosynthesis, carbon metabolism and iron acquisition. Since metabolic changes may lead to oxidative stress, we investigated whether this is the case with nitrogen starvation. Our results rather invalidate this hypothesis thereby suggesting that the function of Pkn22 under nitrogen starvation is independent of its role in response to peroxide stress. Our analyses have permitted a more complete functional description of Ser/Thr kinase in Nostoc. We have decrypted the transcriptional regulation of the pkn22 gene, and analysed the whole set of genes under the control of this kinase in response to the two environmental changes often encountered by cyanobacteria in their natural habitat: oxidative stress and nitrogen deprivation.

  2. Air Quality and Stationary Source Emission Control; Committee on Public Works, Senate, Ninety-Fourth Congress, First Session. [Committee Print.

    ERIC Educational Resources Information Center

    National Academy of Sciences - National Research Council, Washington, DC.

    This report reviews the problems of sulfur oxide emissions and nitrogen oxide emissions from stationary sources. The first part of the report discusses the adverse consequences to health from combustion of sulfur-containing fossil fuels. The health problem is discussed by relating sulfur oxide levels and respirable particulate matter with…

  3. Explosive Ordnance Disposal Proficiency Range and Multi-Purpose Contingency Training Area

    DTIC Science & Technology

    2007-04-01

    1,3,5-trimethylene-2,4,6-trinitramine (RDX), cyclo-1,3,5,7- tetramethylene-2,4,6,8-tetra-nitramine [HMX], tetryl, and picric acid ; inorganic compounds...nitrogen oxides, which cause acid rain. Ir. addition, nitrogen oxide emissions contribute to the problem of global warming and also r;ombine with...of sUlfur oxide and nitrogen oxides, which cause acid ram. Ji:, addition, nitrogen oxide emis~ions contribute to the probl!llll of global warming

  4. DIESEL NOX CONTROL APPLICATION

    EPA Science Inventory

    The paper gives results of a project to design, develop, and demonstrate a diesel engine nitrogen oxide (NOx) and particulate matter (PM) control package that will meet the U.S. Navy's emission control requirements. (NOTE: In 1994, EPA issued a Notice for Proposed Rule Making (NP...

  5. TECHNOLOGICAL OPTIONS FOR ACID RAIN CONTROL

    EPA Science Inventory

    The paper discusses technological options for acid rain control. Compliance with Title IV of the Clean Air Act Amendments of 1990 will require careful scrutiny of a number of issues before selecting control options to reduce sulfur dioxide (SO2) and nitrogen oxide (NOx) emissions...

  6. 40 CFR Table 2 to Subpart Cb of... - Nitrogen Oxides Limits for Existing Designated Facilities Included in an Emissions Averaging Plan...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Nitrogen Oxides Limits for Existing.... 60, Subpt. Cb, Table 2 Table 2 to Subpart Cb of Part 60—Nitrogen Oxides Limits for Existing... by volume) b On and after April 28, 2009, nitrogen oxides emission limit (parts permillion by volume...

  7. 40 CFR Table 2 to Subpart Cb of... - Nitrogen Oxides Limits for Existing Designated Facilities Included in an Emissions Averaging Plan...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Nitrogen Oxides Limits for Existing.... 60, Subpt. Cb, Table 2 Table 2 to Subpart Cb of Part 60—Nitrogen Oxides Limits for Existing... by volume) b On and after April 28, 2009, nitrogen oxides emission limit (parts permillion by volume...

  8. 40 CFR Table 2 to Subpart Cb of... - Nitrogen Oxides Limits for Existing Designated Facilities Included in an Emissions Averaging Plan...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Nitrogen Oxides Limits for Existing.... 60, Subpt. Cb, Table 2 Table 2 to Subpart Cb of Part 60—Nitrogen Oxides Limits for Existing... by volume) b On and after April 28, 2009, nitrogen oxides emission limit (parts permillion by volume...

  9. 40 CFR Table 2 to Subpart Cb of... - Nitrogen Oxides Limits for Existing Designated Facilities Included in an Emissions Averaging Plan...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Nitrogen Oxides Limits for Existing.... 60, Subpt. Cb, Table 2 Table 2 to Subpart Cb of Part 60—Nitrogen Oxides Limits for Existing... by volume) b On and after April 28, 2009, nitrogen oxides emission limit (parts permillion by volume...

  10. 40 CFR Table 2 to Subpart Cb of... - Nitrogen Oxides Limits for Existing Designated Facilities Included in an Emissions Averaging Plan...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Nitrogen Oxides Limits for Existing.... 60, Subpt. Cb, Table 2 Table 2 to Subpart Cb of Part 60—Nitrogen Oxides Limits for Existing... by volume) b On and after April 28, 2009, nitrogen oxides emission limit (parts permillion by volume...

  11. SOURCEBOOK: NOX CONTROL TECHNOLOGY DATA

    EPA Science Inventory

    The report, a compilation of available information on the control of nitrogen oxide (NOx) emissions from stationary sources, is provided to assist new source permitting activities by regulatory agencies. he sources covered are combustion turbines, internal combustion engines, non...

  12. CONTROL OF NOX EMISSIONS FROM U.S. COAL-FIRED ELECTRIC UTILITY BOILERS

    EPA Science Inventory

    The paper discusses the control of nitrogen oxide (NOx) emissions from U.S. coal-fired electric utility boilers. (NOTE: In general, NOx control technologies are categorized as being either primary or secondary control technologies. Primary technologies reduce the amount of NOx pr...

  13. ENGINEERING AND ECONOMIC FACTORS AFFECTING THE INSTALLATION OF CONTROL TECHNOLOGIES FOR MULTIPOLLUTANT STRATEGIES

    EPA Science Inventory

    The report evaluates the engineering and economic factors associated with installing air pollution control technologies to meet the requirements of strategies to control sulfur dioxide (SO2), oxides of nitrogen (NOX), and mercury under the Clear Skies Act multipollutant control s...

  14. Phase formation polycrystalline vanadium oxide via thermal annealing process under controlled nitrogen pressure

    NASA Astrophysics Data System (ADS)

    Jessadaluk, S.; Khemasiri, N.; Rahong, S.; Rangkasikorn, A.; Kayunkid, N.; Wirunchit, S.; Horprathum, M.; Chananonnawathron, C.; Klamchuen, A.; Nukeaw, J.

    2017-09-01

    This article provides an approach to improve and control crystal phases of the sputtering vanadium oxide (VxOy) thin films by post-thermal annealing process. Usually, as-deposited VxOy thin films at room temperature are amorphous phase: post-thermal annealing processes (400 °C, 2 hrs) under the various nitrogen (N2) pressures are applied to improve and control the crystal phase of VxOy thin films. The crystallinity of VxOy thin films changes from amorphous to α-V2O5 phase or V9O17 polycrystalline, which depend on the pressure of N2 carrier during annealing process. Moreover, the electrical resistivity of the VxOy thin films decrease from 105 Ω cm (amorphous) to 6×10-1 Ω cm (V9O17). Base on the results, our study show a simply method to improve and control phase formation of VxOy thin films.

  15. Application of a Chemiluminescence Detector for the Measurement of Total Oxides of Nitrogen and Ammonia in the Atmosphere

    NASA Technical Reports Server (NTRS)

    Hodgeson, J. A.; Bell, J. P.; Rehme, K. A.; Krost, K. J.; Stevens, R. K.

    1971-01-01

    By means of the thermal conversion of nitrogen dioxide to the nitric oxide, the chemiluminescent nitric oxide monitor, based on the nitric oxide plus ozone reaction, may be used for monitoring nitrogen dioxide plus nitric oxide (NO(x)). Under conditions previously described, ammonia is also converted to nitric oxide and therefore interferes. A metal surface, gold wool or stainless steel, operated at two different temperatures has been used to convert only nitrogen dioxide or nitrogen dioxide plus ammonia. Quantitative conversion of nitrogen dioxide to nitric oxide has been obtained at temperatures as low as 200 C. Conversion of ammonia is effected at temperatures of 300 C or higher. By the addition of a converter the basic nitric oxide monitor may be used for measuring NO(x) or NO(x) plus ammonia. As an alternate mode, for a fixed high temperature, a specific scrubber is described for removing NH3 without affecting NO2 concentrations.

  16. Phenylbutyrate improves nitrogen disposal via alternative pathway without eliciting an increase in protein breakdown and catabolism in control and ornithine transcarbamylace-deficient patients

    USDA-ARS?s Scientific Manuscript database

    Phenylbutyrate (PB) is a drug used in urea cycle disorder patients to elicit alternative pathways for nitrogen disposal. However, PB decreases plasma branched chain amino acid (BCAA) concentrations and prior research suggests that PB may increase leucine oxidation, indicating increased protein degra...

  17. 40 CFR 86.005-10 - Emission standards for 2005 and later model year Otto-cycle heavy-duty engines and vehicles.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... megajoule). (B) Oxides of Nitrogen plus Non-methane Hydrocarbon Equivalent (NO X + NMHCE) for engines fueled... Nitrogen plus Non-methane Hydrocarbon Equivalent (NO X + NMHCE) for engines fueled with methanol. 1.5 grams... Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW...

  18. Nitrogen-doped graphene: effect of graphite oxide precursors and nitrogen content on the electrochemical sensing properties.

    PubMed

    Megawati, Monica; Chua, Chun Kiang; Sofer, Zdenek; Klímová, Kateřina; Pumera, Martin

    2017-06-21

    Graphene, produced via chemical methods, has been widely applied for electrochemical sensing due to its structural and electrochemical properties as well as its ease of production in large quantity. While nitrogen-doped graphenes are widely studied materials, the literature showing an effect of graphene oxide preparation methods on nitrogen quantity and chemical states as well as on defects and, in turn, on electrochemical sensing is non-existent. In this study, the properties of nitrogen-doped graphene materials, prepared via hydrothermal synthesis using graphite oxide produced by various classical methods using permanganate or chlorate oxidants Staudenmaier, Hummers, Hofmann and Brodie oxidation methods, were studied; the resulting nitrogen-doped graphene oxides were labeled as ST-GO, HU-GO, HO-GO and BR-GO, respectively. The electrochemical oxidation of biomolecules, such as ascorbic acid, uric acid, dopamine, nicotinamide adenine nucleotide and DNA free bases, was carried out using cyclic voltammetry and differential pulse voltammetry techniques. The nitrogen content in doped graphene oxides increased in the order ST-GO < BR-GO < HO-GO < HU-GO. In the same way, the pyridinic form of nitrogen increased and the electrocatalytic effect of N-doped graphene followed this trend, as shown in the cyclic voltammograms. This is a very important finding that provides insight into the electrocatalytic effect of N-doped graphene. The nitrogen-doped graphene materials exhibited improved sensitivity over bare glassy carbon for ascorbic acid, uric acid and dopamine detection. These studies will enhance our understanding of the effects of graphite oxide precursors on the electrochemical sensing properties of nitrogen-doped graphene materials.

  19. 40 CFR 86.223-94 - Oxides of nitrogen analyzer calibration.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.223-94 Oxides of...

  20. Regional-scale controls on dissolved nitrous oxide in the Upper Mississippi River

    USDA-ARS?s Scientific Manuscript database

    Bottom-up estimates of riverine nitrous oxide (N2O) emissions developed by the Intergovernmental Panel on Climate Change (IPCC) assume a constant emission factor (EF5r) that predicts N2O production from anthropogenic nitrogen inputs. This relation ignores any direct stream water biochemical charact...

  1. NATURAL EMISSIONS OF NON-METHANE VOLATILE ORGANIC COMPOUNDS, CARBON MONOXIDE, AND OXIDES OF NITROGEN FROM NORTH AMERICA. (R825259)

    EPA Science Inventory

    Abstract

    The magnitudes, distributions, controlling processes and uncertainties associated with North American natural emissions of oxidant precursors are reviewed. Natural emissions are responsible for a major portion of the compounds, including non-methane volatile o...

  2. Chemical Characterization and Reactivity of Fuel-Oxidizer Reaction Product

    NASA Technical Reports Server (NTRS)

    David, Dennis D.; Dee, Louis A.; Beeson, Harold D.

    1997-01-01

    Fuel-oxidizer reaction product (FORP), the product of incomplete reaction of monomethylhydrazine and nitrogen tetroxide propellants prepared under laboratory conditions and from firings of Shuttle Reaction Control System thrusters, has been characterized by chemical and thermal analysis. The composition of FORP is variable but falls within a limited range of compositions that depend on three factors: the fuel-oxidizer ratio at the time of formation; whether the composition of the post-formation atmosphere is reducing or oxidizing; and the reaction or post-reaction temperature. A typical composition contains methylhydrazinium nitrate, ammonium nitrate, methylammonium nitrate, and trace amounts of hydrazinium nitrate and 1,1-dimethylhydrazinium nitrate. Thermal decomposition reactions of the FORP compositions used in this study were unremarkable. Neither the various compositions of FORP, the pure major components of FORP, nor mixtures of FORP with propellant system corrosion products showed any unusual thermal activity when decomposed under laboratory conditions. Off-limit thruster operations were simulated by rapid mixing of liquid monomethylhydrazine and liquid nitrogen tetroxide in a confined space. These tests demonstrated that monomethylhydrazine, methylhydrazinium nitrate, ammonium nitrate, or Inconel corrosion products can induce a mixture of monomethylhydrazine and nitrogen tetroxide to produce component-damaging energies. Damaging events required FORP or metal salts to be present at the initial mixing of monomethylhydrazine and nitrogen tetroxide.

  3. Sustainable synthesis of aldehydes, ketones or acids from neat alcohols using nitrogen dioxide gas, and related reactions.

    PubMed

    Naimi-Jamal, M Reza; Hamzeali, Hamideh; Mokhtari, Javad; Boy, Jürgen; Kaupp, Gerd

    2009-01-01

    Benzylic alcohols are quantitatively oxidized by gaseous nitrogen dioxide to give pure aromatic aldehydes. The reaction gas mixtures are transformed to nitric acid, which renders the processes free of waste. The exothermic gas-liquid or gas-solid reactions profit from the solubility of nitrogen dioxide in the neat benzylic alcohols. The acid formed impedes further oxidation of the benzaldehydes. The neat isolated benzaldehydes and nitrogen dioxide quantitatively give the benzoic acids. Solid long-chain primary alcohols are directly and quantitatively oxidized with nitrogen dioxide gas to give the fatty acids in the solid state. The oxidations with ubiquitous nitrogen dioxide are extended to solid heterocyclic thioamides, which gives disulfides, and to diphenylamine, which gives tetraphenylhydrazine. These sustainable (green) specific oxidation procedures produce no dangerous residues from the oxidizing agent or from auxiliaries.

  4. Controllable embedding of sulfur in high surface area nitrogen doped three dimensional reduced graphene oxide by solution drop impregnation method for high performance lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Zegeye, Tilahun Awoke; Tsai, Meng-Che; Cheng, Ju-Hsiang; Lin, Ming-Hsien; Chen, Hung-Ming; Rick, John; Su, Wei-Nien; Kuo, Chung-Feng Jeffrey; Hwang, Bing-Joe

    2017-06-01

    High capacity lithium-sulfur batteries with stable cycle performance and sulfur loadings greater than 70 wt% are regarded as promising candidates for energy storage devices. However, it has been challenged to achieving practical application of sulfur cathode because of low loading of active sulfur and poor cycle performance. Herein, we design novel nanocomposite cathode materials consist of sulfur (80 wt%) embedded within nitrogen doped three-dimensional reduced graphene oxide (N-3D-rGO) by controllable sulfur-impregnation method. Nitrogen doping helps increase the surface area by ten times from pristine graphene, and pore volume by seven times. These structural features allow the cathode to hold more sulfur. It also adsorbs polysulfides and prevents their detachment from the host materials; thereby achieving stable cycle performance. The solution drop sulfur-impregnation method provides uniform distribution of nano-sulfur in controlled manner. The material delivers a high initial discharge capacity of 1042 mAhg-1 and 916 mAhg-1 with excellent capacity retention of 94.8% and 81.9% at 0.2 C and 0.5 C respectively after 100 cycles. Thus, the combination of solution drop and nitrogen doping opens a new chapter for resolving capacity fading as well as long cycling problems and creates a new strategy to increase sulfur loading in controlled mechanism.

  5. Ammonium and nitrite oxidation at nanomolar oxygen concentrations in oxygen minimum zone waters

    PubMed Central

    Bristow, Laura A.; Dalsgaard, Tage; Tiano, Laura; Mills, Daniel B.; Bertagnolli, Anthony D.; Wright, Jody J.; Hallam, Steven J.; Ulloa, Osvaldo; Canfield, Donald E.; Revsbech, Niels Peter; Thamdrup, Bo

    2016-01-01

    A major percentage of fixed nitrogen (N) loss in the oceans occurs within nitrite-rich oxygen minimum zones (OMZs) via denitrification and anammox. It remains unclear to what extent ammonium and nitrite oxidation co-occur, either supplying or competing for substrates involved in nitrogen loss in the OMZ core. Assessment of the oxygen (O2) sensitivity of these processes down to the O2 concentrations present in the OMZ core (<10 nmol⋅L−1) is therefore essential for understanding and modeling nitrogen loss in OMZs. We determined rates of ammonium and nitrite oxidation in the seasonal OMZ off Concepcion, Chile at manipulated O2 levels between 5 nmol⋅L−1 and 20 μmol⋅L−1. Rates of both processes were detectable in the low nanomolar range (5–33 nmol⋅L−1 O2), but demonstrated a strong dependence on O2 concentrations with apparent half-saturation constants (Kms) of 333 ± 130 nmol⋅L−1 O2 for ammonium oxidation and 778 ± 168 nmol⋅L−1 O2 for nitrite oxidation assuming one-component Michaelis–Menten kinetics. Nitrite oxidation rates, however, were better described with a two-component Michaelis–Menten model, indicating a high-affinity component with a Km of just a few nanomolar. As the communities of ammonium and nitrite oxidizers were similar to other OMZs, these kinetics should apply across OMZ systems. The high O2 affinities imply that ammonium and nitrite oxidation can occur within the OMZ core whenever O2 is supplied, for example, by episodic intrusions. These processes therefore compete with anammox and denitrification for ammonium and nitrite, thereby exerting an important control over nitrogen loss. PMID:27601665

  6. Study on a discrete-time dynamic control model to enhance nitrogen removal with fluctuation of influent in oxidation ditches.

    PubMed

    Liu, Yanchen; Shi, Hanchang; Shi, Huiming; Wang, Zhiqiang

    2010-10-01

    The aim of study was proposed a new control model feasible on-line implemented by Programmable Logic Controller (PLC) to enhance nitrogen removal against the fluctuation of influent in Carrousel oxidation ditch. The discrete-time control model was established by confirmation model of operational conditions based on a expert access, which was obtained by a simulation using Activated Sludge Model 2-D (ASM2-D) and Computation Fluid Dynamics (CFD), and discrete-time control model to switch between different operational stages. A full-scale example is provided to demonstrate the feasibility of the proposed operation and the procedure of the control design. The effluent quality was substantially improved, to the extent that it met the new wastewater discharge standards of NH(3)-N<5mg/L and TN<15 mg/L enacted in China throughout a one-day period with fluctuation of influent. Copyright © 2010 Elsevier Ltd. All rights reserved.

  7. 40 CFR 52.34 - Action on petitions submitted under section 126 relating to emissions of nitrogen oxides.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... section 126 relating to emissions of nitrogen oxides. 52.34 Section 52.34 Protection of Environment... of nitrogen oxides. (a) Definitions. For purposes of this section, the following definitions apply... of nitrogen. (6) OTAG means the Ozone Transport Assessment Group (active 1995-1997), a national work...

  8. 40 CFR 52.34 - Action on petitions submitted under section 126 relating to emissions of nitrogen oxides.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... section 126 relating to emissions of nitrogen oxides. 52.34 Section 52.34 Protection of Environment... of nitrogen oxides. (a) Definitions. For purposes of this section, the following definitions apply... of nitrogen. (6) OTAG means the Ozone Transport Assessment Group (active 1995-1997), a national work...

  9. 40 CFR 52.34 - Action on petitions submitted under section 126 relating to emissions of nitrogen oxides.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... section 126 relating to emissions of nitrogen oxides. 52.34 Section 52.34 Protection of Environment... of nitrogen oxides. (a) Definitions. For purposes of this section, the following definitions apply... of nitrogen. (6) OTAG means the Ozone Transport Assessment Group (active 1995-1997), a national work...

  10. 40 CFR 86.523-78 - Oxides of nitrogen analyzer calibration.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... analyzer to optimize performance. (2) Zero the oxides of nitrogen analyzer with zero grade air or zero... samples. Proceed as follows: (1) Adjust analyzer to optimize performance. (2) Zero the oxides of nitrogen analyzer with zero grade air or zero grade nitrogen. (3) Calibrate on each normally used operating range...

  11. Nitrous Oxide Production at a Fully Covered Wastewater Treatment Plant: Results of a Long-Term Online Monitoring Campaign.

    PubMed

    Kosonen, Heta; Heinonen, Mari; Mikola, Anna; Haimi, Henri; Mulas, Michela; Corona, Francesco; Vahala, Riku

    2016-06-07

    The nitrous oxide emissions of the Viikinmäki wastewater treatment plant were measured in a 12 month online monitoring campaign. The measurements, which were conducted with a continuous gas analyzer, covered all of the unit operations of the advanced wastewater-treatment process. The relation between the nitrous oxide emissions and certain process parameters, such as the wastewater temperature, influent biological oxygen demand, and ammonium nitrogen load, was investigated by applying online data obtained from the process-control system at 1 min intervals. Although seasonal variations in the measured nitrous oxide emissions were remarkable, the measurement data indicated no clear relationship between these emissions and seasonal changes in the wastewater temperature. The diurnal variations of the nitrous oxide emissions did, however, strongly correlate with the alternation of the influent biological oxygen demand and ammonium nitrogen load to the aerated zones of the activated sludge process. Overall, the annual nitrous oxide emissions of 168 g/PE/year and the emission factor of 1.9% of the influent nitrogen load are in the high range of values reported in the literature but in very good agreement with the results of other long-term online monitoring campaigns implemented at full-scale wastewater-treatment plants.

  12. Simultaneous removal of nitrogen oxides and sulfur oxides from combustion gases

    DOEpatents

    Clay, David T.; Lynn, Scott

    1976-10-19

    A process for the simultaneous removal of sulfur oxides and nitrogen oxides from power plant stack gases comprising contacting the stack gases with a supported iron oxide catalyst/absorbent in the presence of sufficient reducing agent selected from the group consisting of carbon monoxide, hydrogen, and mixtures thereof, to provide a net reducing atmosphere in the SO.sub.x /NO.sub.x removal zone. The sulfur oxides are removed by absorption substantially as iron sulfide, and nitrogen oxides are removed by catalytic reduction to nitrogen and ammonia. The spent iron oxide catalyst/absorbent is regenerated by oxidation and is recycled to the contacting zone. Sulfur dioxide is also produced during regeneration and can be utilized in the production of sulfuric acid and/or sulfur.

  13. KSC00pp0511

    NASA Image and Video Library

    2000-04-07

    KENNEDY SPACE CENTER, FLA. -- Clyde Parrish, a NASA/KSC engineer, explains how the fertilizer scrubber control panel (center) works to turn nitrogen tetroxide vapor into fertilizer, potassium hydroxide. Parrish developed the system, which uses a "scrubber," to capture nitrogen tetroxide vapor that develops as a by-product when it is transferred from ground storage tanks into the Shuttle storage tanks. Nitrogen tetroxide is used as the oxidizer for the hypergolic propellant in the Shuttle's on-orbit reaction control system. The scrubber then uses hydrogen peroxide to produce nitric acid, which, after adding potassium hydroxide, converts to potassium nitrate. The resulting fertilizer will be used on the orange groves that KSC leases to outside companies

  14. KSC-00pp0511

    NASA Image and Video Library

    2000-04-07

    KENNEDY SPACE CENTER, FLA. -- Clyde Parrish, a NASA/KSC engineer, explains how the fertilizer scrubber control panel (center) works to turn nitrogen tetroxide vapor into fertilizer, potassium hydroxide. Parrish developed the system, which uses a "scrubber," to capture nitrogen tetroxide vapor that develops as a by-product when it is transferred from ground storage tanks into the Shuttle storage tanks. Nitrogen tetroxide is used as the oxidizer for the hypergolic propellant in the Shuttle's on-orbit reaction control system. The scrubber then uses hydrogen peroxide to produce nitric acid, which, after adding potassium hydroxide, converts to potassium nitrate. The resulting fertilizer will be used on the orange groves that KSC leases to outside companies

  15. Nitrogen Dioxide's Impact on Indoor Air Quality

    EPA Pesticide Factsheets

    The two most prevalent oxides of nitrogen are nitrogen dioxide (NO2) and nitric oxide (NO). Both are toxic gases with NO2 being a highly reactive oxidant and corrosive. The primary sources indoors are combustion processes.

  16. Mobile sources critical review: 1998 NARSTO assessment

    NASA Astrophysics Data System (ADS)

    Sawyer, R. F.; Harley, R. A.; Cadle, S. H.; Norbeck, J. M.; Slott, R.; Bravo, H. A.

    Mobile sources of air pollutants encompass a range of vehicle, engine, and fuel combinations. They emit both of the photochemical ozone precursors, hydrocarbons and oxides of nitrogen. The most important source of hydrocarbons and oxides of nitrogen are light- and heavy-duty on-road vehicles and heavy-duty off-road vehicles, utilizing spark and compression ignition engines burning gasoline and diesel respectively. Fuel consumption data provide a convenient starting point for assessing current and future emissions. Modern light-duty, gasoline vehicles when new have very low emissions. The in-use fleet, due largely to emissions from a small "high emitter" fraction, has significantly larger emissions. Hydrocarbons and carbon monoxide are higher than reported in current inventories. Other gasoline powered mobile sources (motorcycles, recreational vehicles, lawn, garden, and utility equipment, and light aircraft) have high emissions on a per quantity of fuel consumed basis, but their contribution to total emissions is small. Additional uncertainties in spatial and temporal distribution of emissions exist. Heavy-duty diesel vehicles are becoming the dominant mobile source of oxides of nitrogen. Oxides of nitrogen emissions may be greater than reported in current inventories, but the evidence for this is mixed. Oxides of nitrogen emissions on a fuel-consumed basis are much greater from diesel mobile sources than from gasoline mobile sources. This is largely the result of stringent control of gasoline vehicle emissions and a lesser (heavy-duty trucks) or no control (construction equipment, locomotives, ships) of heavy-duty mobile sources. The use of alternative fuels, natural gas, propane, alcohols, and oxygenates in motor vehicles is increasing but remains small. Vehicles utilizing these fuels can be but are not necessarily cleaner than their gasoline or diesel counterparts. Historical vehicle kilometers traveled growth rates of about 2% annually in both the United States and Canada will slow somewhat to about 1.5%. Mexican growth rates are expected to be greater. Fuel consumption growth in recent years of about 1.4% annually is projected to continue as slowing gains in fuel economy from fleet turnover are more than offset by growth and the increasing number of Sport Utility Vehicles. This growth also will erode the emissions reductions resulting from cleaner new vehicles and fuels. Uncertainties in these projections are high and affected by economic activity, demographics, and the effectiveness of emissions control programs — especially those for reducing in-use emissions.

  17. Oxidized Nitrogen in Precipitation, Throughfall, and Streamfall from a Forested Watershed in Oklahoma

    USGS Publications Warehouse

    Lawrence, Stephen J.; Wigington, Parker J.

    1987-01-01

    Oxidized nitrogen (nitrite plus nitrate N) concentrations were measured from bulk precipitation, bulk throughfall, and screamflow in a 7. 86 hectare forested watershed in southeastern Oklahoma during the wet season from March through June 1983. Oxidized nitrogen inputs comparable to results of other studies were recorded during the 19 rainstorms sampled. Oxidized nitrogen concentrations appeared to increase after rainfall interacted with the pine and hardwood canopies and were inversely related to both rainfall and throughfall depth. Oxidized N concentrations in streamflow were greatest during the rising limb of storm flow with subsequent decreases during the falling limb of storm hydrographs and lowest during base flow. The oxidized N inputs from bulk precipitation were considerably greater than outputs from streamflow resulting in a net retention of oxidized nitrogen within the watershed during the study period.

  18. Removal of sulfur and nitrogen containing pollutants from discharge gases

    DOEpatents

    Joubert, James I.

    1986-01-01

    Oxides of sulfur and of nitrogen are removed from waste gases by reaction with an unsupported copper oxide powder to form copper sulfate. The resulting copper sulfate is dissolved in water to effect separation from insoluble mineral ash and dried to form solid copper sulfate pentahydrate. This solid sulfate is thermally decomposed to finely divided copper oxide powder with high specific surface area. The copper oxide powder is recycled into contact with the waste gases requiring cleanup. A reducing gas can be introduced to convert the oxide of nitrogen pollutants to nitrogen.

  19. Effect of fuel nitrogen and hydrogen content on emissions in hydrocarbon combustion

    NASA Technical Reports Server (NTRS)

    Bittker, D. A.; Wolfbrandt, G.

    1981-01-01

    How the emissions of nitrogen oxides and carbon monoxide are affected by: (1) the decreased hydrogen content and (2) the increased organic nitrogen content of coal derived fuels is investigated. Previous CRT experimental work in a two stage flame tube has shown the effectiveness of rich lean two stage combustion in reducing fuel nitrogen conversion to nitrogen oxides. Previous theoretical work gave preliminary indications that emissions trends from the flame tube experiment could be predicted by a two stage, well stirred reactor combustor model using a detailed chemical mechanism for propane oxidation and nitrogen oxide formation. Additional computations are reported and comparisons with experimental results for two additional fuels and a wide range of operating conditions are given. Fuels used in the modeling are pure propane, a propane toluene mixture and pure toluene. These give hydrogen contents 18, 11 and 9 percent by weight, respectively. Fuel bound nitrogen contents of 0.5 and 1.0 percent were used. Results are presented for oxides of nitrogen and also carbon monoxide concentrations as a function of primary equivalence ratio, hydrogen content and fuel bound nitrogen content.

  20. The Kinematic and Microphysical Control of Storm Integrated Lightning Flash Extent

    NASA Technical Reports Server (NTRS)

    Carey, Lawrence D.; Koshak, William J.; Peterson, Harold S.; Shultz, Elise; Matthee, Retha; Shultz, Christopher J.; Petersen, Walter A.; Bain, Lamont

    2013-01-01

    To investigate the kinematic and microphysical control of lightning properties, particularly those that may govern the production of nitrogen oxides (NO(x)) in thunderstorms, such as flash rate, type (intracloud (IC) vs. cloud-to-ground (CG)) and extent.

  1. Application of microwave energy in the control of DPM, oxides of nitrogen and VOC emissions

    NASA Astrophysics Data System (ADS)

    Pallavkar, Sameer M.

    The emissions of DPM (diesel particulate matter), NOx (oxides of nitrogen), and toxic VOCs (volatile organic compounds) from diesel engine exhaust gases and other sources such as chemical process industry and manufacturing industry have been a great environmental and health concern. Most control technologies for these emissions require elevated temperatures. The use of microwave energy as a source of heat energy, however, has not been fully explored. In this study, the microwave energy was used as the energy source in three separate emission control processes, namely, the regeneration of diesel particulate filter (DPF) for DPM control, the NOx reduction using a platinum catalyst, and the VOC destruction involving a ceramic based material. The study has demonstrated that microwave heating is an effective method in providing heat for the studied processes. The control efficiencies associated with the microwave-assisted processes have been observed to be high and acceptable. Further research, however, is required for the commercial use of these technologies.

  2. 500 MW demonstration of advanced wall-fired combustion techniques for the reduction of nitrogen oxide emissions from coal-fired boilers

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sorge, J.N.; Larrimore, C.L.; Slatsky, M.D.

    1997-12-31

    This paper discusses the technical progress of a US Department of Energy Innovative Clean Coal Technology project demonstrating advanced wall-fired combustion techniques for the reduction of nitrogen oxide (NOx) emissions from coal-fired boilers. The primary objectives of the demonstration is to determine the long-term NOx reduction performance of advanced overfire air (AOFA), low NOx burners (LNB), and advanced digital control optimization methodologies applied in a stepwise fashion to a 500 MW boiler. The focus of this paper is to report (1) on the installation of three on-line carbon-in-ash monitors and (2) the design and results to date from the advancedmore » digital control/optimization phase of the project.« less

  3. The effect of emission from coal combustion in nonindustrial sources on deposition of sulfur and oxidized nitrogen in Poland.

    PubMed

    Kryza, Maciej; Werner, Małgorzata; Błaś, Marek; Dore, Anthony J; Sobik, Mieczysław

    2010-07-01

    Poland has one of the largest sulfur and nitrogen emissions in Europe. This is mainly because coal is a main fuel in industrial and nonindustrial combustion. The aim of this paper is to assess the amount of sulfur and nitrogen deposited from SNAP sector 02 (nonindustrial sources) coal combustion. To assess this issue, the Fine Resolution Atmospheric Multipollutant Exchange (FRAME) model was used. The results suggest that industrial combustion has the largest impact on deposition of oxidized sulfur, whereas the oxidized nitrogen national deposition budget is dominated by transboundary transport. The total mass of pollutants deposited in Poland, originating from nonindustrial coal combustion, is 45 Gg of sulfur and 2.5 Gg of nitrogen, which is over 18% of oxidized sulfur and nearly 2% of oxidized nitrogen deposited. SNAP 02 is responsible for up to 80% of dry-deposited sulfur and 11% of nitrogen. The contribution to wet deposition is largest in central Poland in the case of sulfur and in some areas can exceed 11%. For oxidized nitrogen, nonindustrial emissions contribute less than 1% over the whole area of Poland. The switch from coal to gas fuel in this sector will result in benefits in sulfur and nitrogen deposition reduction.

  4. Air Pollution Control, Part I.

    ERIC Educational Resources Information Center

    Strauss, Werner, Ed.

    Authoritative reviews in seven areas of current importance in air pollution control are supplied in this volume, the first of a two-part set. Titles contained in this book are: "Dispersion of Pollutants Emitted into the Atmosphere,""The Formation and Control of Oxides of Nitrogen in Air Pollution,""The Control of Sulfur Emissions from Combustion…

  5. 78 FR 38587 - Approval and Promulgation of Air Quality Implementation Plans; Connecticut; Reasonably Available...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-27

    ... reasonably available control technology (RACT) for oxides of nitrogen (NO X ) and volatile organic compounds.... I. Background and Purpose II. Connecticut's Reasonably Available Control Technology Certification... controlling volatile organic compound emissions that Connecticut submitted to EPA on July 20, 2007. \\1\\ The...

  6. Plasma-chemical processes accompanying discharge in air excited by a microwave beam

    NASA Astrophysics Data System (ADS)

    Askar'ian, G. A.; Batanov, G. M.; Gritsinin, S. I.; Kossyi, I. A.; Kostinskii, A. Iu.

    1990-11-01

    Experimental results are presented on plasma-chemical processes of nitrogen oxidation and ozone production accompanying microwave discharge in dry air and in nitrogen-oxygen mixtures. The degree of nitrogen oxidation and the energy expenditure toward the formation of oxides as a function of discharge conditions are established. The experimental results can be explained by assuming oxidation reactions of electron-excited metastable nitrogen molecules by oxygen atoms. Low ozone concentrations in the discharge indicate a significant energy input into the gas.

  7. Electrochemical wastewater treatment: influence of the type of carbon and of nitrogen on the organic load removal.

    PubMed

    Fernandes, Annabel; Coelho, João; Ciríaco, Lurdes; Pacheco, Maria José; Lopes, Ana

    2016-12-01

    Boron-doped diamond (BDD) and Ti/Pt/PbO 2 anodes were utilized to perform the electrodegradation of synthetic samples containing humic acid in the presence of different organic and inorganic carbon-containing and nitrogen-containing compounds. The influence of the chloride ion in the degradation process of the different synthetic samples was also assessed. The results showed that the anodic oxidation process can efficiently degrade recalcitrant compounds such as humic acid. The presence of carbonate in solution enhances the nitrogen removal, whereas it hinders the oxidation of the organic compounds. When organic nitrogen is present, it is converted to NH 4 + , which in turn is oxidized to nitrate and to volatile nitrogen compounds. Hydroxyl radicals are more prone to oxidize the organic nitrogen than the ammonium nitrogen. The presence of chloride enhances the organic matter and nitrogen removal rates, BDD being the anode material that yields the highest removals.

  8. POLLUTANT CONTROL TECHNIQUES FOR PACKAGE BOILERS: HARDWARE MODIFICATIONS AND ALTERNATE FUELS

    EPA Science Inventory

    The report gives results of investigations of four ways to control nitrogen oxide (NOx) emissions from package boilers (both field operating boilers and boiler simulators): (1) variations in combustor operating procedure; (2) combustion modification (flue gas recirculation and st...

  9. Simulation of Liquid Injection Thrust Vector Control for Mars Ascent Vehicle

    NASA Technical Reports Server (NTRS)

    Gudenkauf, Jared

    2017-01-01

    The Jet Propulsion Laboratory is currently in the initial design phase for a potential Mars Ascent Vehicle; which will be landed on Mars, stay on the surface for period of time, collect samples from the Mars 2020 rover, and then lift these samples into orbit around Mars. The engineers at JPL have down selected to a hybrid wax-based fuel rocket using a liquid oxidizer based on nitrogen tetroxide, or a Mixed Oxide of Nitrogen. To lower the gross lift-off mass of the vehicle the thrust vector control system will use liquid injection of the oxidizer to deflect the thrust of the main nozzle instead of using a gimbaled nozzle. The disadvantage of going with the liquid injection system is the low technology readiness level with a hybrid rocket. Presented in this paper is an effort to simulate the Mars Ascent Vehicle hybrid rocket nozzle and liquid injection thrust vector control system using the computational fluid dynamic flow solver Loci/Chem. This effort also includes determining the sensitivity of the thrust vector control system to a number of different design variables for the injection ports; including axial location, number of adjacent ports, injection angle, and distance between the ports.

  10. 76 FR 11082 - Approval and Promulgation of Air Quality Implementation Plans; Ohio; Oxides of Nitrogen Budget...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-01

    ... Promulgation of Air Quality Implementation Plans; Ohio; Oxides of Nitrogen Budget Trading Program; Technical... concerning 240 allowances under the Nitrogen Oxides Budget Trading Program added to the SIP by EPA rulemaking... EPA approve rule revisions [[Page 11083

  11. Treatment of power utilities exhaust

    DOEpatents

    Koermer, Gerald [Basking Ridge, NJ

    2012-05-15

    Provided is a process for treating nitrogen oxide-containing exhaust produced by a stationary combustion source by the catalytic reduction of nitrogen oxide in the presence of a reductant comprising hydrogen, followed by ammonia selective catalytic reduction to further reduce the nitrogen oxide level in the exhaust.

  12. Microbiological Diversity Demonstrates the Potential which Collaboratively Metabolize Nitrogen Oxides ( NOx) under Smog Environmental Stress

    NASA Astrophysics Data System (ADS)

    Chen, X. Z.; Zhao, X. H.; Chen, X. P.

    2018-03-01

    Recently, smoggy weather has become a daily in large part of China because of rapidly economic growth and accelerative urbanization. Stressed on the smoggy situation and economic growth, the green and environment-friendly technology is necessary to reduce or eliminate the smog and promote the sustainable development of economy. Previous studies had confirmed that nitrogen oxides ( NOx ) is one of crucial factors which forms smog. Microorganisms have the advantages of quickly growth and reproduction and metabolic diversity which can collaboratively Metabolize various NOx. This study will design a kind of bacteria & algae cultivation system which can metabolize collaboratively nitrogen oxides in air and intervene in the local nitrogen cycle. Furthermore, the nitrogen oxides can be transformed into nitrogen gas or assembled in protein in microorganism cell by regulating the microorganism types and quantities and metabolic pathways in the system. Finally, the smog will be alleviated or eliminated because of reduction of nitrogen oxides emission. This study will produce the green developmental methodology.

  13. 40 CFR 60.46b - Compliance and performance test methods and procedures for particulate matter and nitrogen oxides.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... and procedures for particulate matter and nitrogen oxides. 60.46b Section 60.46b Protection of... nitrogen oxides. (a) The PM emission standards and opacity limits under § 60.43b apply at all times except... oil having a nitrogen content greater than 0.30 weight percent shall determine compliance with the NOX...

  14. 40 CFR 60.46b - Compliance and performance test methods and procedures for particulate matter and nitrogen oxides.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... and procedures for particulate matter and nitrogen oxides. 60.46b Section 60.46b Protection of... nitrogen oxides. (a) The PM emission standards and opacity limits under § 60.43b apply at all times except... oil having a nitrogen content greater than 0.30 weight percent shall determine compliance with the NOX...

  15. Numerical modelling of emissions of nitrogen oxides in solid fuel combustion.

    PubMed

    Bešenić, Tibor; Mikulčić, Hrvoje; Vujanović, Milan; Duić, Neven

    2018-06-01

    Among the combustion products, nitrogen oxides are one of the main contributors to a negative impact on the environment, participating in harmful processes such as tropospheric ozone and acid rains production. The main source of emissions of nitrogen oxides is the human combustion of fossil fuels. Their formation models are investigated and implemented with the goal of obtaining a tool for studying the nitrogen-containing pollutant production. In this work, numerical simulation of solid fuel combustion was carried out on a three-dimensional model of a drop tube furnace by using the commercial software FIRE. It was used for simulating turbulent fluid flow and temperature field, concentrations of the reactants and products, as well as the fluid-particles interaction by numerically solving the integro-differential equations describing these processes. Chemical reactions mechanisms for the formation of nitrogen oxides were implemented by the user functions. To achieve reasonable calculation times for running the simulations, as well as efficient coupling with the turbulent mixing process, the nitrogen scheme is limited to sufficiently few homogeneous reactions and species. Turbulent fluctuations that affect the reaction rates of nitrogen oxides' concentration are modelled by probability density function approach. Results of the implemented model for nitrogen oxides' formation from coal and biomass are compared to the experimental data. Temperature, burnout and nitrogen oxides' concentration profiles are compared, showing satisfactory agreement. The new model allows the simulation of pollutant formation in the real-world applications. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Multi-stage catalyst systems and uses thereof

    DOEpatents

    Ozkan, Umit S [Worthington, OH; Holmgreen, Erik M [Columbus, OH; Yung, Matthew M [Columbus, OH

    2009-02-10

    Catalyst systems and methods provide benefits in reducing the content of nitrogen oxides in a gaseous stream containing nitric oxide (NO), hydrocarbons, carbon monoxide (CO), and oxygen (O.sub.2). The catalyst system comprises an oxidation catalyst comprising a first metal supported on a first inorganic oxide for catalyzing the oxidation of NO to nitrogen dioxide (NO.sub.2), and a reduction catalyst comprising a second metal supported on a second inorganic oxide for catalyzing the reduction of NO.sub.2 to nitrogen (N.sub.2).

  17. 40 CFR 52.420 - Identification of plan.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 8/11/10, 75 FR 48566 Section 6.0 Ozone 9/11/08 8/11/10, 75 FR 48566 Section 8.0 Nitrogen Dioxide 9... 9/11/08 8/11/10, 75 FR 48566 1112Control of Nitrogen Oxide Emissions Section 1.0 Applicability 9/11... Length of Rolling Period for Liquid/Liquid Material Balance 9/11/08 8/11/10, 75 FR 48566 Appendix K...

  18. 40 CFR 52.420 - Identification of plan.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Ozone 9/11/08 8/11/10, 75 FR 48566 Section 8.0 Nitrogen Dioxide 9/11/08 8/11/10, 75 FR 48566 Section 10... 9/11/08 8/11/10, 75 FR 48566 1112Control of Nitrogen Oxide Emissions Section 1.0 Applicability 9/11... Length of Rolling Period for Liquid/Liquid Material Balance 9/11/08 8/11/10, 75 FR 48566 Appendix K...

  19. A KSC engineer describes the new fertilizer-producing facility near Launch Pad 39A

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Clyde Parrish, a NASA/KSC engineer, explains how the fertilizer scrubber control panel (center) works to turn nitrogen tetroxide vapor into fertilizer, potassium hydroxide. Parrish developed the system, which uses a 'scrubber,' to capture nitrogen tetroxide vapor that develops as a by-product when it is transferred from ground storage tanks into the Shuttle storage tanks. Nitrogen tetroxide is used as the oxidizer for the hypergolic propellant in the Shuttle's on-orbit reaction control system. The scrubber then uses hydrogen peroxide to produce nitric acid, which, after adding potassium hydroxide, converts to potassium nitrate. The resulting fertilizer will be used on the orange groves that KSC leases to outside companies.

  20. 40 CFR 52.2171 - Classification of regions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... quality control region Pollutant Particulate matter Sulfur oxides Nitrogen dioxide Carbon monoxide... Falls Interstate II III III III III Black Hills—Rapid City Intrastate III III III III III South Dakota...

  1. 40 CFR 52.2171 - Classification of regions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... quality control region Pollutant Particulate matter Sulfur oxides Nitrogen dioxide Carbon monoxide... Falls Interstate II III III III III Black Hills—Rapid City Intrastate III III III III III South Dakota...

  2. 40 CFR 52.2171 - Classification of regions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... quality control region Pollutant Particulate matter Sulfur oxides Nitrogen dioxide Carbon monoxide... Falls Interstate II III III III III Black Hills—Rapid City Intrastate III III III III III South Dakota...

  3. 40 CFR 52.2299 - Original identification of plan section.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    .../hydrocarbons in Texas designated regions 7 and 10; regulation VII; and control strategy for nitrogen oxides in... printing; rotogravure printing; surface coating processes; transfer efficiency; and vapor balance system...

  4. 40 CFR 52.2299 - Original identification of plan section.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    .../hydrocarbons in Texas designated regions 7 and 10; regulation VII; and control strategy for nitrogen oxides in... printing; rotogravure printing; surface coating processes; transfer efficiency; and vapor balance system...

  5. An aeration control strategy for oxidation ditch processes based on online oxygen requirement estimation.

    PubMed

    Zhan, J X; Ikehata, M; Mayuzumi, M; Koizumi, E; Kawaguchi, Y; Hashimoto, T

    2013-01-01

    A feedforward-feedback aeration control strategy based on online oxygen requirements (OR) estimation is proposed for oxidation ditch (OD) processes, and it is further developed for intermittent aeration OD processes, which are the most popular type in Japan. For calculating OR, concentrations of influent biochemical oxygen demand (BOD) and total Kjeldahl nitrogen (TKN) are estimated online by the measurement of suspended solids (SS) and sometimes TKN is estimated by NH4-N. Mixed liquor suspended solids (MLSS) and temperature are used to estimate the required oxygen for endogenous respiration. A straightforward parameter named aeration coefficient, Ka, is introduced as the only parameter that can be tuned automatically by feedback control or manually by the operators. Simulation with an activated sludge model was performed in comparison to fixed-interval aeration and satisfying result of OR control strategy was obtained. The OR control strategy has been implemented at seven full-scale OD plants and improvements in nitrogen removal are obtained in all these plants. Among them, the results obtained in Yumoto wastewater treatment plant were presented, in which continuous aeration was applied previously. After implementing intermittent OR control, the total nitrogen concentration was reduced from more than 5 mg/L to under 2 mg/L, and the electricity consumption was reduced by 61.2% for aeration or 21.5% for the whole plant.

  6. S-nitrosothiols regulate nitric oxide production and storage in plants through the nitrogen assimilation pathway

    PubMed Central

    Frungillo, Lucas; Skelly, Michael J.; Loake, Gary J.; Spoel, Steven H.; Salgado, Ione

    2014-01-01

    Nitrogen assimilation plays a vital role in plant metabolism. Assimilation of nitrate, the primary source of nitrogen in soil, is linked to generation of the redox signal nitric oxide (NO). An important mechanism by which NO regulates plant development and stress responses is through S-nitrosylation, i.e. covalent attachment of NO to cysteines to form S-nitrosothiols (SNO). Despite the importance of nitrogen assimilation and NO signalling, it remains largely unknown how these pathways are interconnected. Here we show that SNO signalling suppresses both nitrate uptake and reduction by transporters and reductases, respectively, to fine-tune nitrate homeostasis. Moreover, NO derived from nitrate assimilation suppresses the redox enzyme S-nitrosoglutathione Reductase 1 (GSNOR1) by S-nitrosylation, preventing scavenging of S-nitrosoglutathione, a major cellular bio-reservoir of NO. Hence, our data demonstrates that (S)NO controls its own generation and scavenging by modulating nitrate assimilation and GSNOR1 activity. PMID:25384398

  7. Effect of Nitrogen Source on Growth and Trichloroethylene Degradation by Methane-Oxidizing Bacteria

    PubMed Central

    Chu, Kung-Hui; Alvarez-Cohen, Lisa

    1998-01-01

    The effect of nitrogen source on methane-oxidizing bacteria with respect to cellular growth and trichloroethylene (TCE) degradation ability were examined. One mixed chemostat culture and two pure type II methane-oxidizing strains, Methylosinus trichosporium OB3b and strain CAC-2, which was isolated from the chemostat culture, were used in this study. All cultures were able to grow with each of three different nitrogen sources: ammonia, nitrate, and molecular nitrogen. Both M. trichosporium OB3b and strain CAC-2 showed slightly lower net cellular growth rates and cell yields but exhibited higher methane uptake rates, levels of poly-β-hydroxybutyrate (PHB) production, and naphthalene oxidation rates when grown under nitrogen-fixing conditions. The TCE-degrading ability of each culture was measured in terms of initial TCE oxidation rates and TCE transformation capacities (mass of TCE degraded/biomass inactivated), measured both with and without external energy sources. Higher initial TCE oxidation rates and TCE transformation capacities were observed in nitrogen-fixing mixed, M. trichosporium OB3b, and CAC-2 cultures than in nitrate- or ammonia-supplied cells. TCE transformation capacities were found to correlate with cellular PHB content in all three cultures. The results of this study suggest that the nitrogen-fixing capabilities of methane-oxidizing bacteria can be used to select for high-activity TCE degraders for the enhancement of bioremediation in fixed-nitrogen-limited environments. PMID:9726896

  8. 40 CFR 52.992 - Area-wide nitrogen oxides exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Area-wide nitrogen oxides exemptions. 52.992 Section 52.992 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... nitrogen oxides exemptions. (a) The Louisiana Department of Environmental Quality submitted to the EPA on...

  9. 40 CFR 52.2308 - Area-wide nitrogen oxides (NOX) exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 5 2014-07-01 2014-07-01 false Area-wide nitrogen oxides (NOX) exemptions. 52.2308 Section 52.2308 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR...-wide nitrogen oxides (NOX) exemptions. (a) The Texas Natural Resource Conservation Commission (TNRCC...

  10. 40 CFR 52.992 - Area-wide nitrogen oxides exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Area-wide nitrogen oxides exemptions. 52.992 Section 52.992 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... nitrogen oxides exemptions. (a) The Louisiana Department of Environmental Quality submitted to the EPA on...

  11. 40 CFR 52.2308 - Area-wide nitrogen oxides (NOX) exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 5 2013-07-01 2013-07-01 false Area-wide nitrogen oxides (NOX) exemptions. 52.2308 Section 52.2308 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR...-wide nitrogen oxides (NOX) exemptions. (a) The Texas Natural Resource Conservation Commission (TNRCC...

  12. 40 CFR 52.992 - Area-wide nitrogen oxides exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 3 2012-07-01 2012-07-01 false Area-wide nitrogen oxides exemptions. 52.992 Section 52.992 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... nitrogen oxides exemptions. (a) The Louisiana Department of Environmental Quality submitted to the EPA on...

  13. 40 CFR 52.992 - Area-wide nitrogen oxides exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Area-wide nitrogen oxides exemptions. 52.992 Section 52.992 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... nitrogen oxides exemptions. (a) The Louisiana Department of Environmental Quality submitted to the EPA on...

  14. 40 CFR 52.2308 - Area-wide nitrogen oxides (NOX) exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 5 2012-07-01 2012-07-01 false Area-wide nitrogen oxides (NOX) exemptions. 52.2308 Section 52.2308 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR...-wide nitrogen oxides (NOX) exemptions. (a) The Texas Natural Resource Conservation Commission (TNRCC...

  15. 40 CFR 52.277 - Oxides of nitrogen, combustion gas concentration limitations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Oxides of nitrogen, combustion gas concentration limitations. 52.277 Section 52.277 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Oxides of nitrogen, combustion gas concentration limitations. (a) The following rules are being retained...

  16. 40 CFR 52.277 - Oxides of nitrogen, combustion gas concentration limitations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Oxides of nitrogen, combustion gas concentration limitations. 52.277 Section 52.277 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Oxides of nitrogen, combustion gas concentration limitations. (a) The following rules are being retained...

  17. 40 CFR 52.277 - Oxides of nitrogen, combustion gas concentration limitations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Oxides of nitrogen, combustion gas concentration limitations. 52.277 Section 52.277 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Oxides of nitrogen, combustion gas concentration limitations. (a) The following rules are being retained...

  18. 40 CFR 52.277 - Oxides of nitrogen, combustion gas concentration limitations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 3 2012-07-01 2012-07-01 false Oxides of nitrogen, combustion gas concentration limitations. 52.277 Section 52.277 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Oxides of nitrogen, combustion gas concentration limitations. (a) The following rules are being retained...

  19. 40 CFR 52.277 - Oxides of nitrogen, combustion gas concentration limitations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Oxides of nitrogen, combustion gas concentration limitations. 52.277 Section 52.277 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Oxides of nitrogen, combustion gas concentration limitations. (a) The following rules are being retained...

  20. The Role of Vitamins and Minerals in the Alleviation of Asthma Symptoms

    ERIC Educational Resources Information Center

    Oberholzer, H. M.; Pretorius, E.

    2010-01-01

    The primary focus in managing asthma is the control of inflammation, as asthma is an inflammatory disease. Because of this chronic airway inflammation, the lungs of asthmatic patients are exposed to oxidative stress due to the generation of reactive oxygen- and nitrogen species (ROS and NOS). Oxidative stress therefore plays an important role in…

  1. Simultaneous removal of nitrogen oxide/nitrogen dioxide/sulfur dioxide from gas streams by combined plasma scrubbing technology.

    PubMed

    Chang, Moo Been; Lee, How Ming; Wu, Feeling; Lai, Chi Ren

    2004-08-01

    Oxides of nitrogen (NOx) [nitrogen oxide (NO) + nitrogen dioxide (NO2)] and sulfur dioxide (SO2) are removed individually in traditional air pollution control technologies. This study proposes a combined plasma scrubbing (CPS) system for simultaneous removal of SO2 and NOx. CPS consists of a dielectric barrier discharge (DBD) and wet scrubbing in series. DBD is used to generate nonthermal plasmas for converting NO to NO2. The water-soluble NO2 then can be removed by wet scrubbing accompanied with SO2 removal. In this work, CPS was tested with simulated exhausts in the laboratory and with diesel-generator exhausts in the field. Experimental results indicate that DBD is very efficient in converting NO to NO2. More than 90% removal of NO, NOx, and SO2 can be simultaneously achieved with CPS. Both sodium sulfide (Na2S) and sodium sulfite (Na2SO3) scrubbing solutions are good for NO2 and SO2 absorption. Energy efficiencies for NOx and SO2 removal are 17 and 18 g/kWh, respectively. The technical feasibility of CPS for simultaneous removal of NO, NO2, and SO2 from gas streams is successfully demonstrated in this study. However, production of carbon monoxide as a side-product (approximately 100 ppm) is found and should be considered.

  2. COST OF SELECTIVE CATALYTIC REDUCTION (SCR) APPLICATION FOR NOX CONTROL ON COAL-FIRED BOILERS

    EPA Science Inventory

    The report provides a methodology for estimating budgetary costs associated with retrofit applications of selective catalytic reduction (SCR) technology on coal-fired boilers. SCR is a postcombustion nitrogen oxides (NOx) control technology capable of providing NOx reductions >90...

  3. Assessment of Control Techniques for Reducing Emissions from Locomotive Engines

    DOT National Transportation Integrated Search

    1973-04-01

    The primary objective of this study was to determine the most effective method of reducing emissions of oxides of nitrogen from a two-cylinder version of an EMD series 567C locomotive engine. The NOx control techniques selected for use in this study ...

  4. 76 FR 70352 - Approval and Promulgation of Implementation Plans; Reasonably Available Control Technology for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-14

    ... controlling oxides of nitrogen from the stationary reciprocating, diesel fuel fired, internal combustion... County. The facility contains two stationary reciprocating, diesel fuel fired, internal combustion... Conditions of Approval specify the NO X emissions limits, combustion process adjustments mentioned above...

  5. EPA Research Highlights: Minimizing SO3 Emissions from Coal-Fired Power Plants

    EPA Science Inventory

    There have been substantial reductions in emissions of particulate matter, nitrogen oxides, and sulfur dioxide through the application of control technologies and strategies. The installation of control technologies has added to the complexity of coal-fired boilers and their ope...

  6. 40 CFR 62.4845 - Identification of plan.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Existing Plants (Section 111(d) Plan). (b) The plan was officially submitted as follows: (1) Control of.... (4) Control of metals, acid gases, organic compounds and nitrogen oxide emissions from existing... (LVHC) systems, steam strippers, and waste water treatment plants. Changes have also been made to...

  7. 40 CFR 62.4845 - Identification of plan.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Existing Plants (Section 111(d) Plan). (b) The plan was officially submitted as follows: (1) Control of.... (4) Control of metals, acid gases, organic compounds and nitrogen oxide emissions from existing... (LVHC) systems, steam strippers, and waste water treatment plants. Changes have also been made to...

  8. 40 CFR 62.4845 - Identification of plan.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Existing Plants (Section 111(d) Plan). (b) The plan was officially submitted as follows: (1) Control of.... (4) Control of metals, acid gases, organic compounds and nitrogen oxide emissions from existing... (LVHC) systems, steam strippers, and waste water treatment plants. Changes have also been made to...

  9. [Effects of biochar application on the abundance and structure of ammonia-oxidizer communities in coal-mining area.

    PubMed

    Liu, Yuan; Zhu, Ji Rong; Wu, Yu Chen; Shu, Liang Zuo

    2017-10-01

    As a new type of soil amendment, biochar can effectively improve soil fertility, structure and soil nitrogen transformation. We studied the effects of biochar application on soil properties, abundance and community structure of ammonia oxidizer in coal-mining area. The results showed that the biochar application significantly increased contents of soil NH4+-N, total nitrogen, available phosphorus and potassium. Compared with the control, no change in the abundance of ammonia-oxidizing archaea (AOA) was found under biochar treatment, but there was a significant increase in the abundance of ammonia-oxidizing bacteria (AOB). The analysis of T-RFLP profiles showed that biochar significantly increased the diversity indexes of AOA and AOB, and altered the community structure of both AOA and AOB. Improved soil nutrients as well as increased abundance and diversity of ammonia-oxidizing community to some extent indicated the potential of biochar application in reclamation of coal-mining area soil.

  10. Reduction of nitrogen oxides with catalytic acid resistant aluminosilicate molecular sieves and ammonia

    DOEpatents

    Pence, Dallas T.; Thomas, Thomas R.

    1980-01-01

    Noxious nitrogen oxides in a waste gas stream such as the stack gas from a fossil-fuel-fired power generation plant or other industrial plant off-gas stream is catalytically reduced to elemental nitrogen and/or innocuous nitrogen oxides employing ammonia as reductant in the presence of a zeolite catalyst in the hydrogen or sodium form having pore openings of about 3 to 10 A.

  11. 40 CFR 52.2351 - Area-wide nitrogen oxides (NOX) exemption.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 5 2012-07-01 2012-07-01 false Area-wide nitrogen oxides (NOX) exemption. 52.2351 Section 52.2351 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... nitrogen oxides (NOX) exemption. On May 2, 1997, Ursula Trueman, Director, Division of Air Quality, Utah...

  12. 40 CFR 52.2351 - Area-wide nitrogen oxides (NOX) exemption.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Area-wide nitrogen oxides (NOX) exemption. 52.2351 Section 52.2351 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... nitrogen oxides (NOX) exemption. On May 2, 1997, Ursula Trueman, Director, Division of Air Quality, Utah...

  13. 40 CFR 52.2351 - Area-wide nitrogen oxides (NOX) exemption.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 5 2013-07-01 2013-07-01 false Area-wide nitrogen oxides (NOX) exemption. 52.2351 Section 52.2351 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... nitrogen oxides (NOX) exemption. On May 2, 1997, Ursula Trueman, Director, Division of Air Quality, Utah...

  14. 40 CFR 52.2351 - Area-wide nitrogen oxides (NOX) exemption.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 5 2014-07-01 2014-07-01 false Area-wide nitrogen oxides (NOX) exemption. 52.2351 Section 52.2351 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... nitrogen oxides (NOX) exemption. On May 2, 1997, Ursula Trueman, Director, Division of Air Quality, Utah...

  15. 40 CFR 52.2351 - Area-wide nitrogen oxides (NOX) exemption.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Area-wide nitrogen oxides (NOX) exemption. 52.2351 Section 52.2351 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... nitrogen oxides (NOX) exemption. On May 2, 1997, Ursula Trueman, Director, Division of Air Quality, Utah...

  16. 40 CFR 60.72 - Standard for nitrogen oxides.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standard for nitrogen oxides. 60.72 Section 60.72 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Plants § 60.72 Standard for nitrogen oxides. (a) On and after the date on which the performance test...

  17. 40 CFR 89.112 - Oxides of nitrogen, carbon monoxide, hydrocarbon, and particulate matter exhaust emission standards.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., hydrocarbon, and particulate matter exhaust emission standards. 89.112 Section 89.112 Protection of....112 Oxides of nitrogen, carbon monoxide, hydrocarbon, and particulate matter exhaust emission... emissions of oxides of nitrogen, carbon monoxide, hydrocarbon, and nonmethane hydrocarbon are measured using...

  18. 40 CFR 89.112 - Oxides of nitrogen, carbon monoxide, hydrocarbon, and particulate matter exhaust emission standards.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., hydrocarbon, and particulate matter exhaust emission standards. 89.112 Section 89.112 Protection of....112 Oxides of nitrogen, carbon monoxide, hydrocarbon, and particulate matter exhaust emission... emissions of oxides of nitrogen, carbon monoxide, hydrocarbon, and nonmethane hydrocarbon are measured using...

  19. Catalysts for lean burn engine exhaust abatement

    DOEpatents

    Ott, Kevin C.; Clark, Noline C.; Paffett, Mark T.

    2006-08-01

    The present invention provides a process for catalytically reducing nitrogen oxides in an exhaust gas stream containing nitrogen oxides and a reductant material by contacting the gas stream under conditions effective to catalytically reduce the nitrogen oxides with a catalyst comprising a aluminum-silicate type material and a minor amount of a metal, the catalyst characterized as having sufficient catalytic activity so as to reduce the nitrogen oxides by at least 60 percent under temperatures within the range of from about 200.degree. C. to about 400.degree. C.

  20. Catalysts For Lean Burn Engine Exhaust Abatement

    DOEpatents

    Ott, Kevin C.; Clark, Noline C.; Paffett, Mark T.

    2004-04-06

    The present invention provides a process for catalytically reducing nitrogen oxides in an exhaust gas stream containing nitrogen oxides and a reductant material by contacting the gas stream under conditions effective to catalytically reduce the nitrogen oxides with a catalyst comprising a aluminum-silicate type material and a minor amount of a metal, the catalyst characterized as having sufficient catalytic activity so as to reduce the nitrogen oxides by at least 60 percent under temperatures within the range of from about 200.degree. C. to about 400.degree. C.

  1. Catalysts for lean burn engine exhaust abatement

    DOEpatents

    Ott, Kevin C.; Clark, Noline C.; Paffett, Mark T.

    2003-01-01

    The present invention provides a process for catalytically reducing nitrogen oxides in an exhaust gas stream containing nitrogen oxides and a reductant material by contacting the gas stream under conditions effective to catalytically reduce the nitrogen oxides with a catalyst comprising a aluminum-silicate type material and a minor amount of a metal, the catalyst characterized as having sufficient catalytic activity so as to reduce the nitrogen oxides by at least 60 percent under temperatures within the range of from about 200.degree. C. to about 400.degree. C.

  2. Atmospheric Ionization by Solar Particles Detected by Nitrate Measurements in Antarctic Snow. FY91 AASERT

    NASA Technical Reports Server (NTRS)

    Vitt, Francis M.; Jackman, Charles H.

    1995-01-01

    The odd nitrogen source strengths associated with Solar Proton Events (SPEs), Galactic Cosmic Rays (GCRs), and the oxidation of nitrous oxide in the Earth's middle atmosphere from 1974 through 1993 have been compared globally, at middle and lower latitudes (less than 50 deg), and polar regions (greater than 50 deg) with a two-dimensional (2-D) photochemical transport model. As discovered previously, the oxidation of nitrous oxide dominates the global odd nitrogen source while GCRs and SPEs are significant at polar latitudes. The horizontal transport of odd nitrogen, produced by the oxidation of nitrous oxide at latitudes < 50 deg, was found to be the dominant source of odd nitrogen in the polar regions with GCRs contributing substantially during the entire solar cycle. The source of odd nitrogen from SPEs was more sporadic; however, contributions during several years (mostly near solar maximum) were significant in the polar middle atmosphere.

  3. Regulatory Drivers of Multimedia Reactive Nitrogen Research (Invited)

    NASA Astrophysics Data System (ADS)

    Shaw, S. L.; Knipping, E.; Kumar, N.

    2010-12-01

    The presence of nitrogenous compounds can impact biogeochemical processes in the atmosphere, oceans and freshwater, and land surfaces. As a result, a number of regulations exist that are intended to control the amount and forms of nitrogen present in the environment. These range from the newly proposed Transport Rule, both the primary and secondary National Ambient Air Quality Standards (NAAQS) for nitrogen oxide targeted at ozone and particulate matter formation and nitrogen deposition, and waterbody requirements such as the Total Maximum Daily Load. This talk will cover a subset of research activities at EPRI that inform environmental nitrogen concerns. A multimedia modeling framework has facilitated effect studies of atmospheric loadings on ecosystems. Improvements in emissions estimates, such as for mobile sources, suggest large current underestimates that will substantially impact air quality modeling of nitrogen oxides. Analyses of wintertime nitrate formation in the northern U.S. are demonstrating the roles of NH3 and NOx in particle formation there. Novel measurements of power plant stack emissions suggest operating configurations can influence the isotopic composition of emitted NOx. Novel instruments for ambient measurements of nitrogen, and suggestions for improved deposition estimates, are being developed. EPRI results suggest that multimedia solutions across multiple economic sectors, such as electrification of a wide variety of engines and water quality treatment and trading, have the potential to improve environmental quality effectively.

  4. Method for combined removal of mercury and nitrogen oxides from off-gas streams

    DOEpatents

    Mendelsohn, Marshall H [Downers Grove, IL; Livengood, C David [Lockport, IL

    2006-10-10

    A method for removing elemental Hg and nitric oxide simultaneously from a gas stream is provided whereby the gas stream is reacted with gaseous chlorinated compound to convert the elemental mercury to soluble mercury compounds and the nitric oxide to nitrogen dioxide. The method works to remove either mercury or nitrogen oxide in the absence or presence of each other.

  5. 77 FR 71117 - Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Allegheny County...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-29

    ... Pennsylvania's Control of NO X Emissions From Glass Melting Furnaces AGENCY: Environmental Protection Agency... Environmental Protection (PADEP). The SIP revision adds a regulation to control nitrogen oxides (NO X... controlling NO X emissions from glass melting furnaces. The SIP revision is a regulation that will reduce...

  6. Nitrogen spark denoxer

    DOEpatents

    Ng, Henry K.; Novick, Vincent J.; Sekar, Ramanujam R.

    1997-01-01

    A NO.sub.X control system for an internal combustion engine includes an oxygen enrichment device that produces oxygen and nitrogen enriched air. The nitrogen enriched air contains molecular nitrogen that is provided to a spark plug that is mounted in an exhaust outlet of an internal combustion engine. As the nitrogen enriched air is expelled at the spark gap of the spark plug, the nitrogen enriched air is exposed to a pulsating spark that is generated across the spark gap of the spark plug. The spark gap is elongated so that a sufficient amount of atomic nitrogen is produced and is injected into the exhaust of the internal combustion engine. The injection of the atomic nitrogen into the exhaust of the internal combustion engine causes the oxides of nitrogen to be reduced into nitrogen and oxygen such that the emissions from the engine will have acceptable levels of NO.sub.X. The oxygen enrichment device that produces both the oxygen and nitrogen enriched air can include a selectively permeable membrane.

  7. Thermal oxidation and nitridation of Si nanowalls prepared by metal assisted chemical etching

    NASA Astrophysics Data System (ADS)

    Behera, Anil K.; Viswanath, R. N.; Lakshmanan, C.; Polaki, S. R.; Sarguna, R. M.; Mathews, Tom

    2018-04-01

    Silicon nanowalls with controlled orientation have been prepared using metal assisted chemical etching process. Thermal oxidation and nitridation processes have been carried out on the prepared silicon nanowalls under a control flow of oxygen/nitrogen gases independently at 1050°C for 900s. The morphology and structural properties of the as-prepared, oxidized and nitridated silicon nanowalls have been studied using the scanning electron microscopy and the Grazing incident X-ray diffraction techniques. The results obtained from the analysis of X-ray diffraction patterns and the microscopy images are discussed.

  8. 40 CFR 63.6675 - What definitions apply to this subpart?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... nitrogen oxides (NOX) control device for rich burn engines that, in a two-step reaction, promotes the... reciprocating internal combustion engine which uses reciprocating motion to convert heat energy into mechanical...

  9. The Kinematic and Microphysical Control of Storm Integrated Lightning Flash Extent

    NASA Technical Reports Server (NTRS)

    Carey, Lawrence D.; Peterson, Harold S.; Schultz, Elise V.; Matthee, Retha; Schultz, Christopher J.; Petersen, Walter A,; Bain, Lamont

    2012-01-01

    Objective: To investigate the kinematic and microphysical control of lightning properties, particularly those that may govern the production of nitrogen oxides (NOx) in thunderstorms, such as flash rate, type (intracloud [IC] vs. cloud-to-ground [CG] ) and extent. Data and Methodology: a) NASA MSFC Lightning Nitrogen Oxides Model (LNOM) is applied to North Alabama Lightning Mapping Array (NALMA) and Vaisala National Lightning Detection Network(TradeMark) (NLDN) observations following ordinary convective cells through their lifecycle. b) LNOM provides estimates of flash type, channel length distributions, lightning segment altitude distributions (SADs) and lightning NOx production profiles (Koshak et al. 2012). c) LNOM lightning characteristics are compared to the evolution of updraft and precipitation properties inferred from dual-Doppler (DD) and polarimetric radar analyses of UAHuntsville Advanced Radar for Meteorological and Operational Research (ARMOR, Cband, polarimetric) and KHTX (S-band, Doppler).

  10. Simulation of the impact of thunderstorm activity on atmospheric gas composition

    NASA Astrophysics Data System (ADS)

    Smyshlyaev, S. P.; Mareev, E. A.; Galin, V. Ya.

    2010-08-01

    A chemistry-climate model of the lower and middle atmosphere has been used to estimate the sensitivity of the atmospheric gas composition to the rate of thunderstorm production of nitrogen oxides at upper tropospheric and lower stratospheric altitudes. The impact that nitrogen oxides produced by lightning have on the atmospheric gas composition is treated as a subgrid-scale process and included in the model parametrically. The natural uncertainty in the global production rate of nitrogen oxides in lightning flashes was specified within limits from 2 to 20 Tg N/year. Results of the model experiments have shown that, due to the variability of thunderstorm-produced nitrogen oxides, their concentration in the upper troposphere and lower stratosphere can vary by a factor of 2 or 3, which, given the influence of nitrogen oxides on ozone and other gases, creates the potential for a strong perturbation of the atmospheric gas composition and thermal regime. Model calculations have shown the strong sensitivity of ozone and the OH hydroxyl to the amount of lightning nitrogen oxides at different atmospheric altitudes. These calculations demonstrate the importance of nitrogen oxides of thunderstorm origin for the balance of atmospheric odd ozone and gases linked to it, such as ozone and hydroxyl radicals. Our results demonstrate that one important task is to raise the accuracy of estimates of the rate of nitrogen oxide production by lightning discharges and to use physical parametrizations that take into account the local lightning effects and feedbacks arising in this case rather than climatological data in models of the gas composition and general circulation of the atmosphere.

  11. NATURAL GAS REBURNING FOR NOX CONTROL ON A CYCLONE-FIRED BOILER

    EPA Science Inventory

    The paper discusses natural gas reburning (fuel staging) for nitrogen oxide (NOx) control on a cyclone-fired boiler. eburning is an in-furnace NOx combustion modification technology that has been shown to reduce NOx by 50-60%. eburning is accomplished by injecting fuel downstream...

  12. The Sources of Air Pollution and Their Control.

    ERIC Educational Resources Information Center

    National Air Pollution Control Administration (DHEW), Arlington, VA.

    The problems of air pollution and its control are discussed. Major consideration is given the sources of pollution - motor vehicles, industry, power plants, space heating, and refuse disposal. Annual emission levels of five principle pollutants - carbon monoxide, sulfur dioxide, nitrogen oxides, hydrocarbons, and particulate matter - are listed…

  13. COST OF SELECTIVE CATALYTIC REDUCTION (SCR) APPLICATION FOR NOX CONTROL ON COAL-FIRED BOILERS

    EPA Science Inventory

    The report provides a methodology for estimating budgetary costs associ-ated with retrofit applications of selec-tive catalytic reduction (SCR) technology on coal-fired boilers. SCR is a post-combustion nitrogen oxides (NOX) con-trol technology capable of providing NOX reductions...

  14. 40 CFR 60.55a - Standard for nitrogen oxides.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for nitrogen oxides. 60.55a Section 60.55a Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... § 60.55a Standard for nitrogen oxides. On and after the date on which the initial compliance test is...

  15. 78 FR 54813 - Approval and Promulgation of Air Quality Implementation Plans; Maine; Oxides of Nitrogen...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-06

    ... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Parts 52 [EPA-R01-OAR-2012-0895; FRL- 9900-85-Region1] Approval and Promulgation of Air Quality Implementation Plans; Maine; Oxides of Nitrogen Exemption and... proposed Approval and Promulgation of Air Quality Implementation Plans; Maine; Oxides of Nitrogen Exemption...

  16. 40 CFR 77.6 - Penalties for excess emissions of sulfur dioxide and nitrogen oxides.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... sulfur dioxide and nitrogen oxides. 77.6 Section 77.6 Protection of Environment ENVIRONMENTAL PROTECTION... sulfur dioxide and nitrogen oxides. (a)(1) If excess emissions of sulfur dioxide occur at the affected... under paragraph (a)(1) of this section for any increase in excess emissions of sulfur dioxide determined...

  17. 40 CFR 77.6 - Penalties for excess emissions of sulfur dioxide and nitrogen oxides.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... sulfur dioxide and nitrogen oxides. 77.6 Section 77.6 Protection of Environment ENVIRONMENTAL PROTECTION... sulfur dioxide and nitrogen oxides. (a)(1) If excess emissions of sulfur dioxide occur at the affected... under paragraph (a)(1) of this section for any increase in excess emissions of sulfur dioxide determined...

  18. 40 CFR 77.6 - Penalties for excess emissions of sulfur dioxide and nitrogen oxides.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... sulfur dioxide and nitrogen oxides. 77.6 Section 77.6 Protection of Environment ENVIRONMENTAL PROTECTION... sulfur dioxide and nitrogen oxides. (a)(1) If excess emissions of sulfur dioxide occur at the affected... under paragraph (a)(1) of this section for any increase in excess emissions of sulfur dioxide determined...

  19. 40 CFR 77.6 - Penalties for excess emissions of sulfur dioxide and nitrogen oxides.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... sulfur dioxide and nitrogen oxides. 77.6 Section 77.6 Protection of Environment ENVIRONMENTAL PROTECTION... sulfur dioxide and nitrogen oxides. (a)(1) If excess emissions of sulfur dioxide occur at the affected... under paragraph (a)(1) of this section for any increase in excess emissions of sulfur dioxide determined...

  20. 40 CFR 60.332 - Standard for nitrogen oxides.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... from paragraph (a) of this section. (f) Stationary gas turbines using water or steam injection for... Turbines § 60.332 Standard for nitrogen oxides. (a) On and after the date on which the performance test... stationary gas turbine, any gases which contain nitrogen oxides in excess of: EC16NO91.020 where: STD...

  1. 40 CFR 60.332 - Standard for nitrogen oxides.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... from paragraph (a) of this section. (f) Stationary gas turbines using water or steam injection for... Turbines § 60.332 Standard for nitrogen oxides. (a) On and after the date on which the performance test... stationary gas turbine, any gases which contain nitrogen oxides in excess of: EC16NO91.020 where: STD...

  2. 40 CFR 60.332 - Standard for nitrogen oxides.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... from paragraph (a) of this section. (f) Stationary gas turbines using water or steam injection for... Turbines § 60.332 Standard for nitrogen oxides. (a) On and after the date on which the performance test... stationary gas turbine, any gases which contain nitrogen oxides in excess of: EC16NO91.020 where: STD...

  3. 40 CFR 60.332 - Standard for nitrogen oxides.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... from paragraph (a) of this section. (f) Stationary gas turbines using water or steam injection for... Turbines § 60.332 Standard for nitrogen oxides. (a) On and after the date on which the performance test... stationary gas turbine, any gases which contain nitrogen oxides in excess of: EC16NO91.020 where: STD...

  4. 40 CFR 60.332 - Standard for nitrogen oxides.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... from paragraph (a) of this section. (f) Stationary gas turbines using water or steam injection for... Turbines § 60.332 Standard for nitrogen oxides. (a) On and after the date on which the performance test... stationary gas turbine, any gases which contain nitrogen oxides in excess of: EC16NO91.020 where: STD...

  5. Catalyst for Decomposition of Nitrogen Oxides

    NASA Technical Reports Server (NTRS)

    Schryer, David R. (Inventor); Akyurtlu, Ates (Inventor); Jordan, Jeffrey D. (Inventor); Akyurtlu, Jale (Inventor)

    2015-01-01

    This invention relates generally to a platinized tin oxide-based catalyst. It relates particularly to an improved platinized tin oxide-based catalyst able to decompose nitric oxide to nitrogen and oxygen without the necessity of a reducing gas.

  6. Nitric Oxide Decreases Acute Kidney Injury and Stage 3 Chronic Kidney Disease after Cardiac Surgery.

    PubMed

    Lei, Chong; Berra, Lorenzo; Rezoagli, Emanuele; Yu, Binglan; Dong, Hailong; Yu, Shiqiang; Hou, Lihong; Chen, Min; Chen, Wensheng; Wang, Hongbing; Zheng, Qijun; Shen, Jie; Jin, Zhenxiao; Chen, Tao; Zhao, Rong; Christie, Emily; Sabbisetti, Venkata S; Nordio, Francesco; Bonventre, Joseph V; Xiong, Lize; Zapol, Warren M

    2018-06-22

    No medical intervention has been identified that decreases acute kidney injury and improves renal outcome at 1-year after cardiac surgery. To determine whether administration of nitric oxide reduces the incidence of post-operative acute kidney injury and improves long-term kidney outcomes after multiple cardiac valve replacement requiring prolonged cardiopulmonary bypass. 244 Patients undergoing elective, multiple valve replacement surgery mostly due to rheumatic fever were randomized to receive either nitric oxide (treatment) or nitrogen (control). Nitric oxide and nitrogen were administered via the gas exchanger during cardiopulmonary bypass and by inhalation for 24h post-operatively. Primary outcome: Oxidation of ferrous plasma oxyhemoglobin to ferric methemoglobin was associated to a reduced post-operative acute kidney injury from 64% (control group) to 50% (nitric oxide) (RR, 95% CI; 0.78, 0.62-0.97;P=0.014). At 90-days, transition to stage 3 chronic kidney disease was reduced from 33% in the controls to 21% in the treatment group (RR, 95%CI; 0.64, 0.41 - 0.99;P=0.024); and at 1-year, from 31% to 18% (RR, 95% CI; 0.59, 0.36 - 0.96;P=0.017). Nitric oxide treatment reduced the overall major adverse kidney events at 30-days (RR, 95% CI; 0.40, 0.18 - 0.92;P=0.016, 90-days (RR, 95% CI; 0.40, 0.17 - 0.92;P=0.015 and 1-year (RR, 95% CI; 0.47, 0.20-1.10;P=0.041). In patients undergoing multiple valve replacement and prolonged cardiopulmonary bypass, administration of nitric oxide decreased the incidence of acute kidney injury, transition to stage 3 chronic kidney disease and major adverse kidney events at 30-days, 90-days, and 1-year. Clinical trial registered with ClinicalTrials.gov (NCT01802619).

  7. U.S. nitrogen science plan focuses collaborative efforts

    NASA Astrophysics Data System (ADS)

    Holland, E. A.; Guenther, A.; Lee-Taylor, J.; Bertman, S. B.; Carroll, M. A.; Shepson, P. B.; Sparks, J. P.

    Nitrogen is a major nutrient in terrestrial ecosystems and an important catalyst in tropospheric photochemistry. Over the last century human activities have dramatically increased inputs of reactive nitrogen (Nr, the combination of oxidized, reduced, and organically bound nitrogen) to the Earth system (Figure 1). Nitrogen cycle perturbations have compromised air quality and human health, acidified ecosystems, and degraded and eutrophied lakes and coastal estuaries [Vitousek et al., 1997a, 1997b; Rabalais, 2002; Howarth et al., 2003; Townsend et al., 2003; Galloway et al., 2004].Increased Nr affects global climate. Use of agricultural fertilizers such as ammonium nitrate leads to increased soil production of nitrous oxide (N2O), which has 320 times the global warming potential of carbon dioxide (CO2). Emission of nitrogen oxides (NOx = nitric oxide, NO + nitrogen dioxide, NO2) from fossil fuel burning leads to increases in tropospheric ozone, another greenhouse gas. Ozone is phytotoxic, and may reduce terrestrial CO2 sequestration. To predict the effects of nitrogen cycling changes under changing climatic conditions, there needs to be a better understanding of the global nitrogen budget.

  8. Electrochemical process for the preparation of nitrogen fertilizers

    DOEpatents

    Jiang, Junhua; Aulich, Ted R; Ignatchenko, Alexey V

    2015-04-14

    Methods and apparatus for the preparation of nitrogen fertilizers including ammonium nitrate, urea, urea-ammonium nitrate, and/or ammonia are disclosed. Embodiments include (1) ammonium nitrate produced via the reduction of a nitrogen source at the cathode and the oxidation of a nitrogen source at the anode; (2) urea or its isomers produced via the simultaneous cathodic reduction of a carbon source and a nitrogen source: (3) ammonia produced via the reduction of nitrogen source at the cathode and the oxidation of a hydrogen source or a hydrogen equivalent such as carbon monoxide or a mixture of carbon monoxide and hydrogen at the anode; and (4) urea-ammonium nitrate produced via the simultaneous cathodic reduction of a carbon source and a nitrogen source, and anodic oxidation of a nitrogen source.

  9. Manganese oxide nanowires wrapped with nitrogen doped carbon layers for high performance supercapacitors.

    PubMed

    Li, Ying; Mei, Yuan; Zhang, Lin-Qun; Wang, Jian-Hai; Liu, An-Ran; Zhang, Yuan-Jian; Liu, Song-Qin

    2015-10-01

    In this study, manganese oxide nanowires wrapped by nitrogen-doped carbon layers (MnO(x)@NCs) were prepared by carbonization of poly(o-phenylenediamine) layer coated onto MnO2 nanowires for high performance supercapacitors. The component and structure of the MnO(x)@NCs were controlled through carbonization procedure under different temperatures. Results demonstrated that this composite combined the high conductivity and high specific surface area of nitrogen-doped carbon layers with the high pseudo-capacitance of manganese oxide nanowires. The as-prepared MnO(x)@NCs exhibited superior capacitive properties in 1 M Na2SO4 aqueous solution, such as high conductivity (4.167×10(-3) S cm(-1)), high specific capacitance (269 F g(-1) at 10 mV s(-1)) and long cycle life (134 F g(-1) after 1200 cycles at a scan rate of 50 mV s(-1)). It is reckoned that the present novel hybrid nanowires can serve as a promising electrode material for supercapacitors and other electrochemical devices. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. A microbial biogeochemistry network for soil carbon and nitrogen cycling and methane flux: model structure and application to Asia

    NASA Astrophysics Data System (ADS)

    Xu, X.; Song, C.; Wang, Y.; Ricciuto, D. M.; Lipson, D.; Shi, X.; Zona, D.; Song, X.; Yuan, F.; Oechel, W. C.; Thornton, P. E.

    2017-12-01

    A microbial model is introduced for simulating microbial mechanisms controlling soil carbon and nitrogen biogeochemical cycling and methane fluxes. The model is built within the CN (carbon-nitrogen) framework of Community Land Model 4.5, named as CLM-Microbe to emphasize its explicit representation of microbial mechanisms to biogeochemistry. Based on the CLM4.5, three new pools were added: bacteria, fungi, and dissolved organic matter. It has 11 pools and 34 transitional processes, compared with 8 pools and 9 transitional flow in the CLM4.5. The dissolve organic carbon was linked with a new microbial functional group based methane module to explicitly simulate methane production, oxidation, transport and their microbial controls. Comparing with CLM4.5-CN, the CLM-Microbe model has a number of new features, (1) microbial control on carbon and nitrogen flows between soil carbon/nitrogen pools; (2) an implicit representation of microbial community structure as bacteria and fungi; (3) a microbial functional-group based methane module. The model sensitivity analysis suggests the importance of microbial carbon allocation parameters on soil biogeochemistry and microbial controls on methane dynamics. Preliminary simulations validate the model's capability for simulating carbon and nitrogen dynamics and methane at a number of sites across the globe. The regional application to Asia has verified the model in simulating microbial mechanisms in controlling methane dynamics at multiple scales.

  11. 40 CFR 62.5340 - Identification of Plan.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... from Existing Plants (Section 111(d) Plan). (b) The plan was officially submitted as follows: (1) Control of metals, acid gases, organic compounds and nitrogen oxide emissions from existing municipal... Emissions From Phosphate Fertilizer Plants ...

  12. 40 CFR 62.5340 - Identification of Plan.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... from Existing Plants (Section 111(d) Plan). (b) The plan was officially submitted as follows: (1) Control of metals, acid gases, organic compounds and nitrogen oxide emissions from existing municipal... Emissions From Phosphate Fertilizer Plants ...

  13. 40 CFR 62.5340 - Identification of Plan.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... from Existing Plants (Section 111(d) Plan). (b) The plan was officially submitted as follows: (1) Control of metals, acid gases, organic compounds and nitrogen oxide emissions from existing municipal... Emissions From Phosphate Fertilizer Plants ...

  14. 40 CFR 62.5340 - Identification of Plan.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... from Existing Plants (Section 111(d) Plan). (b) The plan was officially submitted as follows: (1) Control of metals, acid gases, organic compounds and nitrogen oxide emissions from existing municipal... Emissions From Phosphate Fertilizer Plants ...

  15. 40 CFR 62.5340 - Identification of Plan.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... from Existing Plants (Section 111(d) Plan). (b) The plan was officially submitted as follows: (1) Control of metals, acid gases, organic compounds and nitrogen oxide emissions from existing municipal... Emissions From Phosphate Fertilizer Plants ...

  16. Stable and null current hysteresis perovskite solar cells based nitrogen doped graphene oxide nanoribbons hole transport layer

    PubMed Central

    Kim, Jeongmo; Mat Teridi, Mohd Asri; Mohd Yusoff, Abd. Rashid bin; Jang, Jin

    2016-01-01

    Perovskite solar cells are becoming one of the leading technologies to reduce our dependency on traditional power sources. However, the frequently used component poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) has several shortcomings, such as an easily corroded indium-tin-oxide (ITO) interface at elevated temperatures and induced electrical inhomogeneity. Herein, we propose solution-processed nitrogen-doped graphene oxide nanoribbons (NGONRs) as a hole transport layer (HTL) in perovskite solar cells, replacing the conducting polymer PEDOT:PSS. The conversion efficiency of NGONR-based perovskite solar cells has outperformed a control device constructed using PEDOT:PSS. Moreover, our proposed NGONR-based devices also demonstrate a negligible current hysteresis along with improved stability. This work provides an effective route for substituting PEDOT:PSS as the effective HTL. PMID:27277388

  17. VERIFICATION OF SIMPLIFIED PROCEDURES FOR SITE- SPECIFIC SO2 AND NOX CONTROL COST ESTIMATES

    EPA Science Inventory

    The report documents results of an evaluation to verify the accuracy of simplified procedures for estimating sulfur dioxide (S02) and nitrogen oxides (NOx) retrofit control costs and performance for 200 502-emitting coal-fired power plants in the 31-state eastern region. nitially...

  18. 77 FR 41278 - Approval and Promulgation of Air Quality Implementation Plans; Maryland; Reasonably Available...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-13

    ... Promulgation of Air Quality Implementation Plans; Maryland; Reasonably Available Control Technology for the... control technology (RACT) for oxides of nitrogen (NO X ) and volatile organic compounds (VOCs) for the... business information (CBI) or other information whose disclosure is restricted by statute. Certain other...

  19. Final Rule for Control of Emissions From New Marine Compression-Ignition Engines at or Above 2.5 Liters Per Cylinder

    EPA Pesticide Factsheets

    The near-term, Tier 1 standards in this rule are equivalent to the internationally negotiated emission limits for oxides of nitrogen (NOx). These standards will go into effect in 2004 and are based on readily available emission-control technology.

  20. TEST DESIGN FOR ENVIRONMENTAL TECHNOLOGY VERIFICATION (ETV) OF ADD-ON NOX CONTROL UTILIZING OZONE INJECTION

    EPA Science Inventory

    The paper discusses the test design for environmental technology verification (ETV) of add-0n nitrogen oxides (NOx) control utilizing ozone injection. (NOTE: ETV is an EPA-established program to enhance domestic and international market acceptance of new or improved commercially...

  1. INVESTIGATION OF SELECTIVE CATALYTIC REDUCTION IMPACT ON MERCURY SPECIATION UNDER SIMULATED NOX EMISSION CONTROL CONDITIONS

    EPA Science Inventory

    Selective catalytic reduction (SCR) technology is being increasingly applied for controlling emissions of nitrogen oxides (NOx) from coal-fired boilers. Some recent field and pilot studies suggest that the operation of SCR could affect the chemical form of mercury in the coal com...

  2. 40 CFR 62.9350 - Identification of plan.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... plants, submitted by the Oregon State Department of Environmental Quality on June 1, 1977. (2) Control of... reduction plants, submitted by the Oregon State Department of Environmental Quality on January 13, 1981 and August 9, 1982. (4) Control of metals, acid gases, organic compounds and nitrogen oxide emissions from...

  3. 40 CFR 62.9350 - Identification of plan.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... plants, submitted by the Oregon State Department of Environmental Quality on June 1, 1977. (2) Control of... reduction plants, submitted by the Oregon State Department of Environmental Quality on January 13, 1981 and August 9, 1982. (4) Control of metals, acid gases, organic compounds and nitrogen oxide emissions from...

  4. 40 CFR 62.9350 - Identification of plan.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... plants, submitted by the Oregon State Department of Environmental Quality on June 1, 1977. (2) Control of... reduction plants, submitted by the Oregon State Department of Environmental Quality on January 13, 1981 and August 9, 1982. (4) Control of metals, acid gases, organic compounds and nitrogen oxide emissions from...

  5. 40 CFR 62.9350 - Identification of plan.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... plants, submitted by the Oregon State Department of Environmental Quality on June 1, 1977. (2) Control of... reduction plants, submitted by the Oregon State Department of Environmental Quality on January 13, 1981 and August 9, 1982. (4) Control of metals, acid gases, organic compounds and nitrogen oxide emissions from...

  6. Environmental Assessment: Construction and Operation of New Security Forces Facility at Hill Air Force Base, Utah

    DTIC Science & Technology

    2008-10-01

    Quality Standards NEPA National Environmental Policy Act of 1969 NOx Nitrogen Oxides OO-ALC Ogden Air Logistics Center OSHA Occupational Safety...current NAAQS. These standards regulate six common pollutants: carbon monoxide, lead, nitrogen oxides, sulfur oxides, ozone, and particulate matter...with the state plan. The conformity threshold emission level for ozone in maintenance areas is 100 tons per year for nitrogen oxide (NOx) and volatile

  7. 40 CFR 62.14103 - Emission limits for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... combustor metals, acid gases, organics, and nitrogen oxides. 62.14103 Section 62.14103 Protection of... combustor metals, acid gases, organics, and nitrogen oxides. (a) The emission limits for municipal waste combustor metals are specified in paragraphs (a)(1) through (a)(3) of this section. (1) The owner or...

  8. 40 CFR Table 2 to Subpart Fff of... - Nitrogen Oxides Requirements for Affected Facilities

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Nitrogen Oxides Requirements for Affected Facilities 2 Table 2 to Subpart FFF of Part 62 Protection of Environment ENVIRONMENTAL PROTECTION... Before September 20, 1994 Pt. 62, Subpt. FFF, Table 2 Table 2 to Subpart FFF of Part 62—Nitrogen Oxides...

  9. 40 CFR 60.4320 - What emission limits must I meet for nitrogen oxides (NOX)?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false What emission limits must I meet for nitrogen oxides (NOX)? 60.4320 Section 60.4320 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... nitrogen oxides (NOX)? (a) You must meet the emission limits for NOX specified in Table 1 to this subpart...

  10. The Oxides of Nitrogen in Air Pollution.

    ERIC Educational Resources Information Center

    California State Air Resources Board, Sacramento.

    Research on the health effects of oxides of nitrogen and on the role of oxides of nitrogen in producing photochemical smog effects is presented in this report. Prepared by the California State Department of Public Health at the request of the State Legislature, it gives a comprehensive review of available information, as well as the need for air…

  11. 40 CFR 60.4320 - What emission limits must I meet for nitrogen oxides (NOX)?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 6 2011-07-01 2011-07-01 false What emission limits must I meet for nitrogen oxides (NOX)? 60.4320 Section 60.4320 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... nitrogen oxides (NOX)? (a) You must meet the emission limits for NOX specified in Table 1 to this subpart...

  12. 40 CFR 60.4320 - What emission limits must I meet for nitrogen oxides (NOX)?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false What emission limits must I meet for nitrogen oxides (NOX)? 60.4320 Section 60.4320 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... nitrogen oxides (NOX)? (a) You must meet the emission limits for NOX specified in Table 1 to this subpart...

  13. 40 CFR 60.4320 - What emission limits must I meet for nitrogen oxides (NOX)?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false What emission limits must I meet for nitrogen oxides (NOX)? 60.4320 Section 60.4320 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... nitrogen oxides (NOX)? (a) You must meet the emission limits for NOX specified in Table 1 to this subpart...

  14. 40 CFR 60.4320 - What emission limits must I meet for nitrogen oxides (NOX)?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false What emission limits must I meet for nitrogen oxides (NOX)? 60.4320 Section 60.4320 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... nitrogen oxides (NOX)? (a) You must meet the emission limits for NOX specified in Table 1 to this subpart...

  15. 40 CFR 60.46b - Compliance and performance test methods and procedures for particulate matter and nitrogen oxides.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... and procedures for particulate matter and nitrogen oxides. 60.46b Section 60.46b Protection of... NEW STATIONARY SOURCES Standards of Performance for Industrial-Commercial-Institutional Steam... nitrogen oxides. (a) The PM emission standards and opacity limits under § 60.43b apply at all times except...

  16. Prenatal exposure to traffic-related air pollution and risk of early childhood cancers.

    PubMed

    Ghosh, Jo Kay C; Heck, Julia E; Cockburn, Myles; Su, Jason; Jerrett, Michael; Ritz, Beate

    2013-10-15

    Exposure to air pollution during pregnancy has been linked to the risk of childhood cancer, but the evidence remains inconclusive. In the present study, we used land use regression modeling to estimate prenatal exposures to traffic exhaust and evaluate the associations with cancer risk in very young children. Participants in the Air Pollution and Childhood Cancers Study who were 5 years of age or younger and diagnosed with cancer between 1988 and 2008 were had their records linked to California birth certificates, and controls were selected from birth certificates. Land use regression-based estimates of exposures to nitric oxide, nitrogen dioxide, and nitrogen oxides were assigned based on birthplace residence and temporally adjusted using routine monitoring station data to evaluate air pollution exposures during specific pregnancy periods. Logistic regression models were adjusted for maternal age, race/ethnicity, educational level, parity, insurance type, and Census-based socioeconomic status, as well as child's sex and birth year. The odds of acute lymphoblastic leukemia increased by 9%, 23%, and 8% for each 25-ppb increase in average nitric oxide, nitrogen dioxide, and nitrogen oxide levels, respectively, over the entire pregnancy. Second- and third-trimester exposures increased the odds of bilateral retinoblastoma. No associations were found for annual average exposures without temporal components or for any other cancer type. These results lend support to a link between prenatal exposure to traffic exhaust and the risk of acute lymphoblastic leukemia and bilateral retinoblastoma.

  17. Electrochemical process for the preparation of nitrogen fertilizers

    DOEpatents

    Aulich, Ted R.; Olson, Edwin S.; Jiang, Junhua

    2013-03-19

    The present invention provides methods and apparatus for the preparation of nitrogen fertilizers including ammonium nitrate, urea, urea-ammonium nitrate, and/or ammonia utilizing a source of carbon, a source of nitrogen, and/or a source of hydrogen. Implementing an electrolyte serving as ionic charge carrier, (1) ammonium nitrate is produced via the reduction of a nitrogen source at the cathode and the oxidation of a nitrogen source at the anode; (2) urea or its isomers are produced via the simultaneous cathodic reduction of a carbon source and a nitrogen source; (3) ammonia is produced via the reduction of nitrogen source at the cathode and the oxidation of a hydrogen source at the anode; and (4) urea-ammonium nitrate is produced via the simultaneous cathodic reduction of a carbon source and a nitrogen source, and anodic oxidation of a nitrogen source. The electrolyte can be solid.

  18. Method For Selective Catalytic Reduction Of Nitrogen Oxides

    DOEpatents

    Mowery-Evans, Deborah L.; Gardner, Timothy J.; McLaughlin, Linda I.

    2005-02-15

    A method for catalytically reducing nitrogen oxide compounds (NO.sub.x, defined as nitric oxide, NO, +nitrogen dioxide, NO.sub.2) in a gas by a material comprising a base metal consisting essentially of CuO and Mn, and oxides of Mn, on an activated metal hydrous metal oxide support, such as HMO:Si. A promoter, such as tungsten oxide or molybdenum oxide, can be added and has been shown to increase conversion efficiency. This method provides good conversion of NO.sub.x to N.sub.2, good selectivity, good durability, resistance to SO.sub.2 aging and low toxicity compared with methods utilizing vanadia-based catalysts.

  19. Method for selective catalytic reduction of nitrogen oxides

    DOEpatents

    Mowery-Evans, Deborah L [Broomfield, CO; Gardner, Timothy J [Albuquerque, NM; McLaughlin, Linda I [Albuquerque, NM

    2005-02-15

    A method for catalytically reducing nitrogen oxide compounds (NO.sub.x, defined as nitric oxide, NO, +nitrogen dioxide, NO.sub.2) in a gas by a material comprising a base metal consisting essentially of CuO and Mn, and oxides of Mn, on an activated metal hydrous metal oxide support, such as HMO:Si. A promoter, such as tungsten oxide or molybdenum oxide, can be added and has been shown to increase conversion efficiency. This method provides good conversion of NO.sub.x to N.sub.2, good selectivity, good durability, resistance to SO.sub.2 aging and low toxicity compared with methods utilizing vanadia-based catalysts.

  20. Study Uncovers Dirty Little Secret: Soil Emissions are Much-Bigger-than-Expected Component of Air Pollution

    NASA Technical Reports Server (NTRS)

    Stricherz, Vince

    2005-01-01

    Nitrogen oxides produced by huge fires and fossil fuel combustion are a major component of air pollution. They are the primary ingredients in ground-level ozone, a pollutant harmful to human health and vegetation. But new research led by a University of Washington atmospheric scientist shows that, in some regions, nitrogen oxides emitted by the soil are much greater than expected and could play a substantially larger role in seasonal air pollution than previously believed. Nitrogen oxide emissions total more than 40 million metric tons worldwide each year, with 64 percent coming from fossil fuel combustion, 14 percent from burning and a surprising 22 percent from soil, said Lyatt Jaegle, a UW assistant professor of atmospheric sciences. The new research shows that the component from soil is about 70 percent greater than scientists expected. Instead of relying on scattered ground-based measurements of burning and combustion and then extrapolating a global total for nitrogen oxide emissions, the new work used actual observations recorded in 2000 by the Global Ozone Monitoring Experiment aboard the European Space Agency's European Remote Sensing 2 satellite. Nitrogen oxide emissions from fossil fuel combustion are most closely linked to major population centers and show up in the satellite's ozone-monitoring measurements of nitrogen dioxide, part of the nitrogen oxides family.

  1. Cross-system comparisons of soil nitrogen transformations and nitrous oxide flux in tropical forest ecosystems

    NASA Technical Reports Server (NTRS)

    Matson, Pamela A.; Vitousek, Peter M.

    1987-01-01

    Soil nitrogen transformations and nitrous oxide flux across the soil-air interface have been measured in a variety of tropical forest sites and correlated with patterns of nitrogen circulation. Nitrogen mineralizaton and nitrification potentials were found to be high in the relatively fertile Costa Rica sites and the Amazonian oxisol/ultisols, intermediate in Amazonian white sand soils, and low in the Hawaiian montane sites. Nitrous oxide fluxes ranged from 0 to 6.2 ng/sq cm per h, and the mean flux per site was shown to be highly correlated with mean nitrogen mineralization.

  2. Environmental Assessment for Infrastructure Improvements in the Base Developed Area at Eielson Air Force Base, Alaska

    DTIC Science & Technology

    2011-03-01

    utilizing aqueous ammonia used to control nitrogen oxide and dry flue gas desulfurization used to control sulfur dioxide) will be included as part of...blowers; boiler combustion air and forced draft fans; boiler flue gas ; induced draft fans and stacks; as well as extensions of the plant control

  3. Environmental Assessment for Infrastructure Improvements in the Base Developed Area at Eielson Air Force Base, Alaska

    DTIC Science & Technology

    2011-03-01

    aqueous ammonia used to control nitrogen oxide and dry flue gas desulfurization used to control sulfur dioxide) will be included as part of the...boiler combustion air and forced draft fans; boiler flue gas ; induced draft fans and stacks; as well as extensions of the plant control; electrical

  4. Bacterial gene abundances as indicators of greenhouse gas emission in soils.

    PubMed

    Morales, Sergio E; Cosart, Theodore; Holben, William E

    2010-06-01

    Nitrogen fixing and denitrifying bacteria, respectively, control bulk inputs and outputs of nitrogen in soils, thereby mediating nitrogen-based greenhouse gas emissions in an ecosystem. Molecular techniques were used to evaluate the relative abundances of nitrogen fixing, denitrifying and two numerically dominant ribotypes (based on the > or =97% sequence similarity at the 16S rRNA gene) of bacteria in plots representing 10 agricultural and other land-use practices at the Kellogg biological station long-term ecological research site. Quantification of nitrogen-related functional genes (nitrite reductase, nirS; nitrous oxide reductase, nosZ; and nitrogenase, nifH) as well as two dominant 16S ribotypes (belonging to the phyla Acidobacteria, Thermomicrobia) allowed us to evaluate the hypothesis that microbial community differences are linked to greenhouse gas emissions under different land management practices. Our results suggest that the successional stages of the ecosystem are strongly linked to bacterial functional group abundance, and that the legacy of agricultural practices can be sustained over decades. We also link greenhouse gas emissions with specific compositional responses in the soil bacterial community and assess the use of denitrifying gene abundances as proxies for determining nitrous oxide emissions from soils.

  5. Effects of NOx control and plume mixing on nighttime chemical processing of plumes from coal-fired power plants

    NASA Astrophysics Data System (ADS)

    Brown, Steven S.; Dubé, William P.; Karamchandani, Prakash; Yarwood, Greg; Peischl, Jeff; Ryerson, Thomas B.; Neuman, J. Andrew; Nowak, John B.; Holloway, John S.; Washenfelder, Rebecca A.; Brock, Charles A.; Frost, Gregory J.; Trainer, Michael; Parrish, David D.; Fehsenfeld, Frederick C.; Ravishankara, A. R.

    2012-04-01

    Coal-fired electric power plants produce a large fraction of total U.S. NOx emissions, but NOx from this sector has been declining in the last decade owing to installation of control technology. Nighttime aircraft intercepts of plumes from two different Texas power plants (Oklaunion near Wichita Falls and W. A. Parish near Houston) with different control technologies demonstrate the effect of these reductions on nighttime NOxoxidation rates. The analysis shows that the spatial extent of nighttime-emitted plumes to be quite limited and that mixing of highly concentrated plume NOx with ambient ozone is a determining factor for its nighttime oxidation. The plume from the uncontrolled plant had full titration of ozone through 74 km/2.4 h of downwind transport that suppressed nighttime oxidation of NO2 to higher oxides of nitrogen across the majority of the plume. The plume from the controlled plant did not have sufficient NOx to titrate background ozone, which led to rapid nighttime oxidation of NO2 during downwind transport. A plume model that includes horizontal mixing and nighttime chemistry reproduces the observed structures of the nitrogen species in the plumes from the two plants. The model shows that NOx controls not only reduce the emissions directly but also lead to an additional overnight NOx loss of 36-44% on average. The maximum reduction for 12 h of transport in darkness was 73%. The results imply that power plant NOxemissions controls may produce a larger than linear reduction in next-day, downwind ozone production following nighttime transport.

  6. Method of removing oxides of sulfur and oxides of nitrogen from exhaust gases

    DOEpatents

    Walker, Richard J.

    1986-01-01

    A continuous method is presented for removing both oxides of sulfur and oxides of nitrogen from combustion or exhaust gases with the regeneration of the absorbent. Exhaust gas is cleaned of particulates and HCl by a water scrub prior to contact with a liquid absorbent that includes an aqueous solution of bisulfite and sulfite ions along with a metal chelate, such as, an iron or zinc aminopolycarboxylic acid. Following contact with the combustion gases the spent absorbent is subjected to electrodialysis to transfer bisulfite ions into a sulfuric acid solution while splitting water with hydroxide and hydrogen ion migration to equalize electrical charge. The electrodialysis stack includes alternate layers of anion selective and bipolar membranes. Oxides of nitrogen are removed from the liquid absorbent by air stripping at an elevated temperature and the regenerated liquid absorbent is returned to contact with exhaust gases for removal of sulfur oxides and nitrogen oxides.

  7. Nitrogen-Doped Carbon Nanotube-Supported Pd Catalyst for Improved Electrocatalytic Performance toward Ethanol Electrooxidation

    NASA Astrophysics Data System (ADS)

    Wei, Ying; Zhang, Xinyuan; Luo, Zhiyong; Tang, Dian; Chen, Changxin; Zhang, Teng; Xie, Zailai

    2017-07-01

    In this study, hydrothermal carbonization (HTC) was applied for surface functionalization of carbon nanotubes (CNTs) in the presence of glucose and urea. The HTC process allowed the deposition of thin nitrogen-doped carbon layers on the surface of the CNTs. By controlling the ratio of glucose to urea, nitrogen contents of up to 1.7 wt% were achieved. The nitrogen-doped carbon nanotube-supported Pd catalysts exhibited superior electrochemical activity for ethanol oxidation relative to the pristine CNTs. Importantly, a 1.5-fold increase in the specific activity was observed for the Pd/HTC-N1.67%CNTs relative to the catalyst without nitrogen doping (Pd/HTC-CNTs). Further experiments indicated that the introduction of nitrogen species on the surface of the CNTs improved the Pd(0) loading and increased the binding energy.

  8. ATMOSPHERIC NITROGEN FIXATION BY METHANE-OXIDIZING BACTERIA

    PubMed Central

    Davis, J. B.; Coty, V. F.; Stanley, J. P.

    1964-01-01

    Davis, J. B. (Socony Mobil Oil Co., Inc., Dallas, Tex.), V. F. Coty, and J. P. Stanley. Atmospheric nitrogen fixation by methane-oxidizing bacteria. J. Bacteriol. 88:468–472. 1964.—Methane-oxidizing bacteria capable of fixing atmospheric nitrogen were isolated from garden soil, pond mud, oil field soil, and soil exposed to natural gas, indicating a rather wide prevalence in nature. This may explain the high concentration of organic nitrogen commonly found in soils exposed to gas leakage from pipelines or natural-gas seeps. Added molybdenum was a requirement for growth in a nitrogen-free mineral salts medium. All nitrogen-fixing, methane-oxidizing bacteria isolated were gram-negative, nonsporeforming, usually motile rods. Colonies were light yellow, yellow, or white. The most common isolate, which formed light-yellow colonies, is referred to as Pseudomonas methanitrificans sp. n., and is distinguished from Pseudomonas (Methanomonas) methanica by nitrogen-fixing ability and a preponderance of poly-β-hydroxybutyrate in the cellular lipid fraction. Images PMID:14203365

  9. Nitrapyrin addition mitigates nitrous oxide emissions and raises nitrogen use efficiency in plastic-film-mulched drip-fertigated cotton field.

    PubMed

    Liu, Tao; Liang, Yongchao; Chu, Guixin

    2017-01-01

    Nitrification inhibitors (NIs) have been used extensively to reduce nitrogen losses and increase crop nitrogen nutrition. However, information is still scant regarding the influence of NIs on nitrogen transformation, nitrous oxide (N2O) emission and nitrogen utilization in plastic-film-mulched calcareous soil under high frequency drip-fertigated condition. Therefore, a field trial was conducted to evaluate the effect of nitrapyrin (2-chloro-6-(trichloromethyl)-pyridine) on soil mineral nitrogen (N) transformation, N2O emission and nitrogen use efficiency (NUE) in a drip-fertigated cotton-growing calcareous field. Three treatments were established: control (no N fertilizer), urea (225 kg N ha-1) and urea+nitrapyrin (225 kg N ha-1+2.25 kg nitrapyrin ha-1). Compared with urea alone, urea plus nitrapyrin decreased the average N2O emission fluxes by 6.6-21.8% in June, July and August significantly in a drip-fertigation cycle. Urea application increased the seasonal cumulative N2O emission by 2.4 kg N ha-1 compared with control, and nitrapyrin addition significantly mitigated the seasonal N2O emission by 14.3% compared with urea only. During the main growing season, the average soil ammonium nitrogen (NH4+-N) concentration was 28.0% greater and soil nitrate nitrogen (NO3--N) concentration was 13.8% less in the urea+nitrapyrin treatment than in the urea treatment. Soil NO3--N and water-filled pore space (WFPS) were more closely correlated than soil NH4+-N with soil N2O fluxes under drip-fertigated condition (P<0.001). Compared with urea alone, urea plus nitrapyrin reduced the seasonal N2O emission factor (EF) by 32.4% while increasing nitrogen use efficiency by 10.7%. The results demonstrated that nitrapyrin addition significantly inhibited soil nitrification and maintained more NH4+-N in soil, mitigated N2O losses and improved nitrogen use efficiency in plastic-film-mulched calcareous soil under high frequency drip-fertigated condition.

  10. Nitrapyrin addition mitigates nitrous oxide emissions and raises nitrogen use efficiency in plastic-film-mulched drip-fertigated cotton field

    PubMed Central

    Liu, Tao; Chu, Guixin

    2017-01-01

    Nitrification inhibitors (NIs) have been used extensively to reduce nitrogen losses and increase crop nitrogen nutrition. However, information is still scant regarding the influence of NIs on nitrogen transformation, nitrous oxide (N2O) emission and nitrogen utilization in plastic-film-mulched calcareous soil under high frequency drip-fertigated condition. Therefore, a field trial was conducted to evaluate the effect of nitrapyrin (2-chloro-6-(trichloromethyl)-pyridine) on soil mineral nitrogen (N) transformation, N2O emission and nitrogen use efficiency (NUE) in a drip-fertigated cotton-growing calcareous field. Three treatments were established: control (no N fertilizer), urea (225 kg N ha-1) and urea+nitrapyrin (225 kg N ha-1+2.25 kg nitrapyrin ha-1). Compared with urea alone, urea plus nitrapyrin decreased the average N2O emission fluxes by 6.6–21.8% in June, July and August significantly in a drip-fertigation cycle. Urea application increased the seasonal cumulative N2O emission by 2.4 kg N ha-1 compared with control, and nitrapyrin addition significantly mitigated the seasonal N2O emission by 14.3% compared with urea only. During the main growing season, the average soil ammonium nitrogen (NH4+-N) concentration was 28.0% greater and soil nitrate nitrogen (NO3--N) concentration was 13.8% less in the urea+nitrapyrin treatment than in the urea treatment. Soil NO3--N and water-filled pore space (WFPS) were more closely correlated than soil NH4+-N with soil N2O fluxes under drip-fertigated condition (P<0.001). Compared with urea alone, urea plus nitrapyrin reduced the seasonal N2O emission factor (EF) by 32.4% while increasing nitrogen use efficiency by 10.7%. The results demonstrated that nitrapyrin addition significantly inhibited soil nitrification and maintained more NH4+-N in soil, mitigated N2O losses and improved nitrogen use efficiency in plastic-film-mulched calcareous soil under high frequency drip-fertigated condition. PMID:28481923

  11. Observations of Nitrogen Oxides Diurnal Variations and Eddy Covariance Fluxes above a Mixed Hardwood Forest during the 2016 PROPHET-AMOS Campaign

    NASA Astrophysics Data System (ADS)

    Shi, Q.; Kavassalis, S.; Moravek, A.; Steiner, A.; Murphy, J. G.

    2017-12-01

    Nitrogen oxides (NOx = NO + NO2) are important constituents in the atmosphere because they can control ozone production and undergo oxidation reactions with other species. Deposition and emission of NOx can impact the ecosystem by influencing the nitrogen cycle, vegetation health and forest carbon storage. Exchange of NOx between the atmosphere and biosphere is poorly understood due to a lack of direct observations. Here, we present results of nitrogen oxides observations and eddy covariance fluxes above a forest from the 2016 PROPHET-AMOS summer field campaign using a custom built AQD NOxy instrument. This field site is in a mixed deciduous and coniferous forest located in northern Michigan, with a research tower available for above-canopy measurements. Observations made at 29 m show the mixing ratio of NO and NO2 ranges from 0 to 640 ppt and 68 to 3600 ppt respectively. The night-time NO mixing ratio is close to zero, while NO2 builds up to a median of around 700 ppt. A maximum mixing ratio of NO resulting from photolysis of NO2 is frequently observed in the early morning. Median midday NO and NO2 mixing ratios are 50 ppt and 500 ppt. Fluxes calculated by eddy covariance showed an upward flux of NO2 and a downward flux of NO, which is an example of chemical flux divergence due to fast chemistry and diminished solar radiation below the canopy. Daytime fluxes of NO and NO2 peak at similar times in the morning, resulting in a net downward NOx flux with a maximum around 2.5 ppt m/s. To better explain NOx flux observations in this forest, results are compared to previous measurements of the total deposition budget of reactive nitrogen oxides, as well as results from 1-D canopy model FORCAsT.

  12. 40 CFR 52.38 - What are the requirements of the Federal Implementation Plans (FIPs) under the Transport Rule (TR...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Federal Implementation Plans (FIPs) under the Transport Rule (TR) relating to emissions of nitrogen oxides... emissions of nitrogen oxides? (a)(1) The TR NOX Annual Trading Program provisions set forth in subpart AAAAA... annual emissions of nitrogen oxides (NOX). (2) The provisions of subpart AAAAA of part 97 of this chapter...

  13. 40 CFR 52.35 - What are the requirements of the Federal Implementation Plans (FIPs) for the Clean Air Interstate...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... nitrogen oxides? 52.35 Section 52.35 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... (CAIR) relating to emissions of nitrogen oxides? (a)(1) The Federal CAIR NOX Annual Trading Program... provisions that relate to annual emissions of nitrogen oxides (NOX). Each State that is described in § 51.123...

  14. 40 CFR 52.38 - What are the requirements of the Federal Implementation Plans (FIPs) under the Transport Rule (TR...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Federal Implementation Plans (FIPs) under the Transport Rule (TR) relating to emissions of nitrogen oxides... emissions of nitrogen oxides? (a)(1) The TR NOX Annual Trading Program provisions set forth in subpart AAAAA... annual emissions of nitrogen oxides (NOX). (2) The provisions of subpart AAAAA of part 97 of this chapter...

  15. 40 CFR 52.35 - What are the requirements of the Federal Implementation Plans (FIPs) for the Clean Air Interstate...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... nitrogen oxides? 52.35 Section 52.35 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... (CAIR) relating to emissions of nitrogen oxides? (a)(1) The Federal CAIR NOX Annual Trading Program... provisions that relate to annual emissions of nitrogen oxides (NOX). Each State that is described in § 51.123...

  16. 40 CFR 52.35 - What are the requirements of the Federal Implementation Plans (FIPs) for the Clean Air Interstate...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... nitrogen oxides? 52.35 Section 52.35 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... (CAIR) relating to emissions of nitrogen oxides? (a)(1) The Federal CAIR NOX Annual Trading Program... provisions that relate to annual emissions of nitrogen oxides (NOX). Each State that is described in § 51.123...

  17. 40 CFR 52.35 - What are the requirements of the Federal Implementation Plans (FIPs) for the Clean Air Interstate...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... nitrogen oxides? 52.35 Section 52.35 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... (CAIR) relating to emissions of nitrogen oxides? (a)(1) The Federal CAIR NOX Annual Trading Program... provisions that relate to annual emissions of nitrogen oxides (NOX). Each State that is described in § 51.123...

  18. 40 CFR 52.38 - What are the requirements of the Federal Implementation Plans (FIPs) under the Transport Rule (TR...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Federal Implementation Plans (FIPs) under the Transport Rule (TR) relating to emissions of nitrogen oxides... emissions of nitrogen oxides? (a)(1) The TR NOX Annual Trading Program provisions set forth in subpart AAAAA... annual emissions of nitrogen oxides (NOX). (2) The provisions of subpart AAAAA of part 97 of this chapter...

  19. 40 CFR 52.35 - What are the requirements of the Federal Implementation Plans (FIPs) for the Clean Air Interstate...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... nitrogen oxides? 52.35 Section 52.35 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... (CAIR) relating to emissions of nitrogen oxides? (a)(1) The Federal CAIR NOX Annual Trading Program... provisions that relate to annual emissions of nitrogen oxides (NOX). Each State that is described in § 51.123...

  20. Arginase Inhibitor in the Pharmacological Correction of Endothelial Dysfunction

    PubMed Central

    Pokrovskiy, Mihail V.; Korokin, Mihail V.; Tsepeleva, Svetlana A.; Pokrovskaya, Tatyana G.; Gureev, Vladimir V.; Konovalova, Elena A.; Gudyrev, Oleg S.; Kochkarov, Vladimir I.; Korokina, Liliya V.; Dudina, Eleonora N.; Babko, Anna V.; Terehova, Elena G.

    2011-01-01

    This paper is about a way of correction of endothelial dysfunction with the inhibitor of arginase: L-norvaline. There is an imbalance between vasoconstriction and vasodilatation factors of endothelium on the basis of endothelial dysfunction. Among vasodilatation agents, nitrogen oxide plays the basic role. Amino acid L-arginine serves as a source of molecules of nitrogen oxide in an organism. Because of the high activity of arginase enzyme which catalyzes the hydrolysis of L-arginine into ornithine and urea, the bioavailability of nitrogen oxide decreases. The inhibitors of arginase suppress the activity of the given enzyme, raising and production of nitrogen oxide, preventing the development of endothelial dysfunction. PMID:21747978

  1. Defect pair formation in fluorine and nitrogen codoped TiO2

    NASA Astrophysics Data System (ADS)

    Kordatos, A.; Kelaidis, N.; Chroneos, A.

    2018-04-01

    Titanium oxide is extensively investigated because of its high chemical stability and its photocatalytic properties; nevertheless, the large band gap limits its activity to a small portion of the solar spectrum. Nitrogen and fluorine codoping is an efficient defect engineering strategy to increase the photocatalytic activity of titanium oxide. In the present study, we apply density functional theory to investigate the interaction of nitrogen with fluorine and the formation of defect pairs. We show that in fluorine and nitrogen codoped titanium oxide, the FiNi, FONi, and FiNTi defects can form. Their impact on the electronic structure of titanium oxide is discussed.

  2. NOX CONTROL TECHNOLOGIES APPLICABLE TO MUNICIPAL WASTE COMBUSTION

    EPA Science Inventory

    The report documents the key design and operating parameters, commercial status, demonstrated performance, and cost of three technologies available for reducing nitrogen oxide (NOx) emissions from municipal waste combustors (MWCs), and identifies technology research and developme...

  3. Influence of edaphic and management factors on the diversity and abundance of ammonia-oxidizing thaumarchaeota and bacteria in soils of bioenergy crop cultivars.

    PubMed

    Bertagnolli, Anthony D; Meinhardt, Kelley A; Pannu, Manmeet; Brown, Sally; Strand, Stuart; Fransen, Steven C; Stahl, David A

    2015-04-01

    Ammonia-oxidizing thaumarcheota (AOA) and ammonia-oxidizing bacteria (AOB) differentially influence soil and atmospheric chemistry, but soil properties that control their distributions are poorly understood. In this study, the ammonia monooxygenase gene (amoA) was used to identify and quantify presumptive AOA and AOB and relate their distributions to soil properties in two experimental fields planted with different varieties of switchgrass (Panicum virgatum), a potential bioenergy feedstock. Differences in ammonia oxidizer diversity were associated primarily with soil properties of the two field sites, with pH displaying significant correlations with both AOA and AOB population structure. Percent nitrogen (%N), carbon to nitrogen ratios (C : N), and pH were also correlated with shifts nitrifier population structure. Nitrosotalea-like and Nitrosospira cluster II populations were more highly represented in acidic soils, whereas populations affiliated with Nitrososphaera and Nitrosospira cluster 3A.1 were relatively more abundant in alkaline soils. AOA were the dominant functional group in all plots based on quantitative polymerase chain reaction and high-throughput sequencing analyses. These data suggest that AOA contribute significantly to nitrification rates in carbon and nitrogen rich soils influenced by perennial grasses. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  4. Influence of dissolved gases and heat treatments on the oxidative degradation of polyunsaturated fatty acids enriched dairy beverage.

    PubMed

    Giroux, Hélène J; Acteau, Geneviève; Sabik, Hassan; Britten, Michel

    2008-07-23

    The combined effect of dissolved gas composition and heat treatment on the oxidative degradation of a dairy beverage enriched with 2% linseed oil was studied. The dairy beverage was saturated with air, nitrogen, or a nitrogen/hydrogen mixture (4% hydrogen) before pasteurization or sterilization. Saturation with either nitrogen or a nitrogen/hydrogen mixture decreased the dissolved oxygen concentration in dairy beverages (Delta = 7.7 ppm), and the presence of hydrogen significantly reduced the redox potential (Delta = 287 mV). Heat treatments also reduced the oxygen content and redox potential, sterilization being more effective than pasteurization. Both pasteurization and sterilization induced the oxidative degradation of the beverages. On average, the propanal concentration increased by a factor of 2.3 after pasteurization and by a factor of 6.2 after sterilization. However, during storage, sterilized beverages resisted light-induced oxidation better than unheated or pasteurized beverages. Furthermore, saturation with nitrogen or a nitrogen/hydrogen mixture significantly reduced oxidative degradation and provided some protection against color changes during storage.

  5. Microbial Nitrogen Cycling Associated with the Early Diagenesis of Organic Matter in Subseafloor Sediments

    NASA Astrophysics Data System (ADS)

    Zhao, R.

    2015-12-01

    The early diagenesis of organic matter is the major energy source of marine sedimentary biosphere and thus controls its population size; however, the vertical distribution of any functional groups along with the diagenesis of organic matter is remained unclear, especially for those microbes involved in nitrogen transformation which serve as a major control on the nitrogen flux between reservoirs. Here we investigated the vertical distributions of various functional groups in five sediment cores retrieved from Arctic Mid-Ocean Ridge (AMOR), with emphasis on the nitrifiers, denitrifiers and anaerobic ammonium oxidizing bacteria (anammox). We observed the clear geochemical zonation associated with organic matter diagenesis in the sediments based on the pore water profiles of oxygen, nitrate, ammonium, manganese and sulfate, with distinct geochemical transition zones at the boundaries of geochemical zones, including oxic-anoxic transition zone (OATZ) and nitrate-manganese reduction zone (NMTZ). Nitrate was produced in surface oxygenated sediments and nitrate consumption mainly took place at the NMTZ, splitted between re-oxidation of ammonium and manganese (II). Abundances of ammonia oxidizers, nitrite oxidizers, and denitrifiers, estimated through quantitative PCR targeting their respective functional genes, generally decrease with depth, but constantly elevated around the OATZ, NMTZ, and manganese-reduction zone as well. Anammox bacteria were only detected around the NMTZ where both nitrate/nitrite and ammonium are available. These depth profiles of functional groups were also confirmed by the community structure profiling by prokaryotic 16S rRNA gene tag pyrosequencing. Cell-specific rates of nitrification and denitrification, calculated from the bulk net reaction rates divided by functional group abundances, were similar to those values from oligotrophic sediments like North Pond and thus suggested that nitrifiers and denitirifiers populations were in maintenance state. This study illustrated the microbial nitrogen transformation accompanying the early diagenesis of organic matter in marine sediments, which scenario might be occurring in a wide range of stratified environments on Earth.

  6. NITROGEN DIOXIDE, PULMONARY FUNCTION, AND RESPIRATORY DISEASE

    EPA Science Inventory

    Concern as to the toxicity of the oxides of nitrogen has been frequently expressed in clinical and toxicological literature. Oxides of nitrogen are highly reactive compounds and suggest toxic effects on biological systems. The earliest evidence for potential damage to man occurre...

  7. Bioturbation determines the response of benthic ammonia-oxidizing microorganisms to ocean acidification

    PubMed Central

    Laverock, B.; Kitidis, V.; Tait, K.; Gilbert, J. A.; Osborn, A. M.; Widdicombe, S.

    2013-01-01

    Ocean acidification (OA), caused by the dissolution of increasing concentrations of atmospheric carbon dioxide (CO2) in seawater, is projected to cause significant changes to marine ecology and biogeochemistry. Potential impacts on the microbially driven cycling of nitrogen are of particular concern. Specifically, under seawater pH levels approximating future OA scenarios, rates of ammonia oxidation (the rate-limiting first step of the nitrification pathway) have been shown to dramatically decrease in seawater, but not in underlying sediments. However, no prior study has considered the interactive effects of microbial ammonia oxidation and macrofaunal bioturbation activity, which can enhance nitrogen transformation rates. Using experimental mesocosms, we investigated the responses to OA of ammonia oxidizing microorganisms inhabiting surface sediments and sediments within burrow walls of the mud shrimp Upogebia deltaura. Seawater was acidified to one of four target pH values (pHT 7.90, 7.70, 7.35 and 6.80) in comparison with a control (pHT 8.10). At pHT 8.10, ammonia oxidation rates in burrow wall sediments were, on average, fivefold greater than in surface sediments. However, at all acidified pH values (pH ≤ 7.90), ammonia oxidation rates in burrow sediments were significantly inhibited (by 79–97%; p < 0.01), whereas rates in surface sediments were unaffected. Both bacterial and archaeal abundances increased significantly as pHT declined; by contrast, relative abundances of bacterial and archaeal ammonia oxidation (amoA) genes did not vary. This research suggests that OA could cause substantial reductions in total benthic ammonia oxidation rates in coastal bioturbated sediments, leading to corresponding changes in coupled nitrogen cycling between the benthic and pelagic realms. PMID:23980243

  8. The Determination of Total Nitrogen Oxides in Stack Gases. Phenoldisulfonic Acid Method.

    ERIC Educational Resources Information Center

    Thorpe, Charles J. D.

    The well known Saltzman method for oxides of nitrogen is intended for the determination of these constituents in the ambient atmosphere in the range of a few parts per billion to about 5ppm. However, when sulfur dioxide is present in the gas to be sampled and/or the concentration range of the oxides of nitrogen is from five to several thousand…

  9. Reduced-graphene-oxide supported tantalum-based electrocatalysts: Controlled nitrogen doping and oxygen reduction reaction

    NASA Astrophysics Data System (ADS)

    Yang, Xiaoyun; Mo, Qijie; Guo, Yulin; Chen, Nana; Gao, Qingsheng

    2018-03-01

    Controlled N-doping is feasible to engineer the surface stoichiometry and the electronic configuration of metal-oxide electrocatalysts toward efficient oxygen reduction reactions (ORR). Taking reduced graphene oxide supported tantalum-oxides (TaOx/RGO) for example, this work illustrated the controlled N-doping in both metal-oxides and carbon supports, and the contribution to the improved ORR activity. The active N-doped TaOx/RGO electrocatalysts were fabricated via SiO2-assisted pyrolysis, in which the amount and kind of N-doping were tailored toward efficient electrocatalysis. The optimal nanocomposites showed a quite positive half-wave potential (0.80 V vs. RHE), the excellent long-term stability, and the outstanding tolerance to methanol crossing. The improvement in ORR was reasonably attributed to the synergy between N-doped TaOx and N-doped RGO. Elucidating the importance of controlled N-doping for electrocatalysis, this work will open up new opportunities to explore noble-metal-free materials for renewable energy applications.

  10. LOW-CONCENTRATION NOX EMISSIONS MEASUREMENT

    EPA Science Inventory

    The paper gives results of a recent series of low-concentration nitrogen oxides (NOx) emission measurements, made by Midwest Research Institute (MRI) during U.S. EPA-sponsored Environmental Technology Verification (ETV) test of a NOx control system called Xonon (TM) Cool Combust...

  11. INSIDE EPA RESEARCH

    EPA Science Inventory

    The article discusses air pollution research at the U.S. EPA, and particularly AEERL's role in that research which, in some areas, predates the Agency's. EPA's engineering research programs are shifting from an initial focus on sulfur dioxide and nitrogen oxide pollution control ...

  12. EVALUATION OF SIMULTANEOUS SO2/NOX CONTROL TECHNOLOGY

    EPA Science Inventory

    The report gives results of work concentrating on characterizing three process operational parameters of a technology that combines sorbent injection and selective non-catalytic reduction for simultaneous sulfur dioxide/nitrogen oxide (SO2/NOx) removal from coal-fired industrial ...

  13. 76 FR 29680 - Approval and Disapproval and Promulgation of State Implementation Plan Revisions; Infrastructure...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-23

    ... 10, Nitrogen oxides, approved by EPA May 31, 1972 (37 FR 10842). WAQSR, Section 4, Sulfur oxides..., approved by EPA on May 31, 1972 (37 FR 10842). WAQSR, Section 4, Sulfur oxides, approved by EPA June 10... standards for nitrogen oxides; Section 4, Emission standard for sulfur oxides; Section 5, Emission standards...

  14. Biological nitric oxide signalling: chemistry and terminology

    PubMed Central

    Heinrich, Tassiele A; da Silva, Roberto S; Miranda, Katrina M; Switzer, Christopher H; Wink, David A; Fukuto, Jon M

    2013-01-01

    Biological nitrogen oxide signalling and stress is an area of extreme clinical, pharmacological, toxicological, biochemical and chemical research interest. The utility of nitric oxide and derived species as signalling agents is due to their novel and vast chemical interactions with a variety of biological targets. Herein, the chemistry associated with the interaction of the biologically relevant nitrogen oxide species with fundamental biochemical targets is discussed. Specifically, the chemical interactions of nitrogen oxides with nucleophiles (e.g. thiols), metals (e.g. hemeproteins) and paramagnetic species (e.g. dioxygen and superoxide) are addressed. Importantly, the terms associated with the mechanisms by which NO (and derived species) react with their respective biological targets have been defined by numerous past chemical studies. Thus, in order to assist researchers in referring to chemical processes associated with nitrogen oxide biology, the vernacular associated with these chemical interactions is addressed. PMID:23617570

  15. Denitrifying SUP05 Require Exogenous Nitrogen

    NASA Astrophysics Data System (ADS)

    Shah, V.; Chang, B. X.; Morris, R. M.

    2016-02-01

    Members of the SUP05 clade of gamma-proteobacteria are among the most abundant chemoautotrophs in the ocean. Environmental sequencing studies suggest that they have critical roles in mediating carbon fixation, denitrification, and sulfur oxidation in oxygen minimum zones (OMZs). They have evaded cultivation and little is known about the specific growth requirements or substrate ranges that determine their abundance, distribution and impact on marine biogeochemical cycles. We evaluated the genetic potential of an isolate from the SUP05 clade "Ca. Thioglobus autotrophica strain EF1" to fix carbon, reduce nitrogen and oxidize sulfur under anaerobic growth conditions. Growth experiments support genomic predictions, indicating that strain EF1 is a facultatively anaerobic sulfur-oxidizing chemolithoautotroph that reduces nitrate to nitrite and nitric oxide to nitrous oxide. These experiments also revealed that strain EF1 is limited for growth by ammonium, which indicates that it requires an exogenous source of nitrogen for biosynthesis. Evidence that SUP05 cells produce nitrite and nitrous oxide and require exogenous nitrogen suggests that they have important roles in nitrogen cycling and that their growth is ultimately limited by the degradation of sinking organic matter.

  16. Nitrous oxide emissions from yellow brown soil as affected by incorporation of crop residues with different carbon-to-nitrogen ratios: a case study in central China.

    PubMed

    Lin, Shan; Iqbal, Javed; Hu, Ronggui; Shaaban, Muhammad; Cai, Jianbo; Chen, Xi

    2013-08-01

    To investigate the influence of crop residues decomposition on nitrous oxide (N2O) emission, a field study was performed with application of crop residues with different C:N ratios in a bare yellow brown soil at the experimental station of Zhangjiachong at Zigui, China. We set up six experimental treatments: no crop residue (CK), rapeseed cake (RC), potato stalk (PS), rice straw (RS), wheat straw (WS), and corn straw (CS). The carbon (C) to nitrogen (N) ratios of these crop residues were 7.5, 32.9, 40.4, 65.7, and 90.9, respectively. Nitrous oxide fluxes were measured using a static closed chamber method. N2O emissions were significantly enhanced by incorporation of crop residues. Cumulative N2O emissions negatively correlated with C:N ratio (R (2) = 0.9821) of the crop residue, but they were positively correlated with average concentrations of dissolved organic carbon and microbial biomass carbon. Nitrogen emission fraction, calculated as N2O-N emissions originated from the crop residues N, positively correlated with C:N ratio of the residues (P < 0.05). Soil temperature did, whereas soil moisture did not, control the residue's induced N2O emissions because a significant correlation (P < 0.01) existed between soil temperature and N2O emissions in all treatments except the control. In contrast, a significant relationship between soil moisture and N2O emissions was found in the control only. Furthermore, N2O emission significantly correlated (P < 0.05) with NO3 (-)-N, and NH4 (+)-N contents from all residue treatments. These results indicate that (1) crop residues with distinct carbon and nitrogen contents can significantly alter soil N2O flux rates; and (2) soil biotic as well as abiotic variables are critical in determining soil-atmospheric N2O emissions after crop residue incorporation into soil.

  17. Deciphering the metabolic response of M ycobacterium tuberculosis to nitrogen stress

    PubMed Central

    Williams, Kerstin J.; Jenkins, Victoria A.; Barton, Geraint R.; Bryant, William A.; Krishnan, Nitya

    2015-01-01

    Summary A key component to the success of M ycobacterium tuberculosis as a pathogen is the ability to sense and adapt metabolically to the diverse range of conditions encountered in vivo, such as oxygen tension, environmental pH and nutrient availability. Although nitrogen is an essential nutrient for every organism, little is known about the genes and pathways responsible for nitrogen assimilation in M . tuberculosis. In this study we have used transcriptomics and chromatin immunoprecipitation and high‐throughput sequencing to address this. In response to nitrogen starvation, a total of 185 genes were significantly differentially expressed (96 up‐regulated and 89 down regulated; 5% genome) highlighting several significant areas of metabolic change during nitrogen limitation such as nitrate/nitrite metabolism, aspartate metabolism and changes in cell wall biosynthesis. We identify GlnR as a regulator involved in the nitrogen response, controlling the expression of at least 33 genes in response to nitrogen limitation. We identify a consensus GlnR binding site and relate its location to known transcriptional start sites. We also show that the GlnR response regulator plays a very different role in M . tuberculosis to that in non‐pathogenic mycobacteria, controlling genes involved in nitric oxide detoxification and intracellular survival instead of genes involved in nitrogen scavenging. PMID:26077160

  18. The contribution of anaerobic ammonium oxidation to nitrogen loss in two temperate eutrophic estuaries

    NASA Astrophysics Data System (ADS)

    Teixeira, Catarina; Magalhães, Catarina; Joye, Samantha B.; Bordalo, Adriano A.

    2014-04-01

    Studies of anaerobic ammonium oxidation (anammox) continue to show the significance of this metabolic pathway for the removal of nitrogen (N) in several natural environments, including estuaries. However, the seasonal dynamics of the anammox process and related environmental controls within estuarine systems remains poorly explored. We evaluated the seasonal anammox activity along a salinity gradient in two temperate Atlantic estuaries, the Ave and the Douro (NW Portugal). Anammox potential rates were measured in anaerobic sediment slurries using 15N-labeled NO3- and NH4+ amendments. Production of 29N2 and 30N2 in the slurries was quantified using membrane inlet mass spectrometry (MIMS). Environmental characteristics of the sediment and water column were also monitored. Anammox potentials in the Ave and Douro estuarine sediments varied between 0.8-8.4, and 0-2.9 nmol cm-3 wet sediment h-1, respectively, with high seasonal and spatial fluctuations. Inorganic nitrogen availability emerged as the primary environmental control of anammox activity, while water temperature appeared to modulate seasonal variations. The contribution of anammox to overall N2 production averaged over 20%, suggesting that the role of anammox in removing fixed N from these two systems cannot be neglected.

  19. Evaluations of catalysts for wet oxidation waste management in CELSS

    NASA Astrophysics Data System (ADS)

    Oguchi, Mitsuo; Nitta, Keiji

    1992-11-01

    A wet oxidation method is considered to be one of the most effective methods of waste processing and recycling in CELSS (Controlled Ecological Life Support System). The first test using rabbit waste as raw material was conducted under a decomposition temperature of 280 °C for 30 minutes and an initial pure oxygen pressure of 4.9 MPa (50 kgf/cm2) before heating, and the following results were obtained. The value of COD (Chemical Oxygen Demand) was reduced 82.5 % by the wet oxidation. And also the Kjeldahl nitrogen concentration was decreased 98.8%. However, the organic carbon compound in the residual solution was almost acetic acid and ammonia was produced. In order to activate the oxidation more strongly, the second tests using catalysts such as Pd, Ru and Ru+Rh were conducted. As the results of these tests, the effectiveness of catalysts for oxidizing raw material ws shown as follows: COD and the Kjeldahl nitrogen values were drastically decreased 99.65 % and 99.88 %, respectively. Furthermore, the quantity of acetic acid and ammonia were reduced considerably. On the other hand, nitrate was showed a value 30 times as much as without catalytic oxidation.

  20. High temperature decomposition of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2005-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  1. High Temperature Decomposition of Hydrogen Peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2004-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydropemxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  2. OXIDATION AND DEVOLATILIZATION OF NITROGEN IN COAL CHAR

    EPA Science Inventory

    The reactions of organically-bound nitrogen in coal char during combustion have been studied in a laboratory furnace using size-graded char particles prepared by the pyrolysis of a Montana lignite. The time-resolved variations of nitrogen-to-carbon ratio during char oxidation hav...

  3. An analytical study of nitrogen oxides and carbon monoxide emissions in hydrocarbon combustion with added nitrogen, preliminary results

    NASA Technical Reports Server (NTRS)

    Bittker, D. A.

    1979-01-01

    The effect of combustor operating conditions on the conversion of fuel-bound nitrogen (FBN) to nitrogen oxides NO sub x was analytically determined. The effect of FBN and of operating conditions on carbon monoxide (CO) formation was also studied. For these computations, the combustor was assumed to be a two stage, adiabatic, perfectly-stirred reactor. Propane-air was used as the combustible mixture and fuel-bound nitrogen was simulated by adding nitrogen atoms to the mixture. The oxidation of propane and formation of NO sub x and CO were modeled by a fifty-seven reaction chemical mechanism. The results for NO sub x and CO formation are given as functions of primary and secondary stage equivalence ratios and residence times.

  4. Spatial and temporal variability of nitrate and nitrous oxide concentrations in the unsaturated zone at a corn field in the US Midwest

    NASA Astrophysics Data System (ADS)

    Gopalakrishnan, G.; Negri, C.

    2011-12-01

    There has been a significant increase in reactive nitrogen in the environment as a result of human activity. Reactive nitrogen of anthropogenic origin now equals that derived from natural terrestrial nitrogen fixation and is expected to exceed it by the end of the decade. Nitrogen is applied to crops as fertilizer and impacts the environment through water quality impairments (mostly as nitrate) and as greenhouse gas emissions (as nitrous oxide). Research on environmental impacts resulting from nitrogen application in the form of fertilizers has focused disproportionately on the degradation of water quality from agricultural non-point sources. The impacts of this degradation are registered both locally, with runoff and percolation of agrochemicals into local surface water and groundwater, and on a larger scale, such as the increase in the anoxic zone in the Gulf of Mexico attributed to nitrate from the Mississippi River. Impacts to the global climate from increased production of nitrous oxide as a result of increased fertilization are equally significant. Nitrous oxide is a greenhouse gas with a warming potential that is approximately 300 times greater than carbon dioxide. Direct emissions of nitrous oxide from the soil have been expressed as 1% of the applied nitrogen. Indirect emissions due to runoff, leaching and volatilization of the nitrogen from the field have been expressed as 0.75% of the applied nitrogen. Many studies have focused on processes governing nitrogen fluxes in the soil, surface water and groundwater systems. However, research on the biogeochemical processes regulating nitrogen fluxes in the unsaturated zone and consequent impacts on nitrate and nitrous oxide concentrations in groundwater are lacking. Our study explores the spatial and temporal variability of nitrate and nitrous oxide concentrations in the vadose zone at a 15 acre corn field in the US Midwest and links it to the concentrations found in the groundwater at the field site. Results indicated that nitrate concentrations in the vadose zone were an order of magnitude greater than in the groundwater. Nitrous oxide concentrations were significantly less in the vadose zone, suggesting that conditions for microbial degradation of the nitrate were not optimal. There was significant short-term variability in the nitrate concentrations as well as spatial variability over the field site. While the processes governing the linkage between nitrogen concentrations in the unsaturated and saturated zones are still unclear, our research suggests that current models may overestimate the indirect emissions of nitrous oxide produced in agricultural systems.

  5. Effect of nitrogen addition on the structural, electrical, and optical properties of In-Sn-Zn oxide thin films

    NASA Astrophysics Data System (ADS)

    Jia, Junjun; Torigoshi, Yoshifumi; Suko, Ayaka; Nakamura, Shin-ichi; Kawashima, Emi; Utsuno, Futoshi; Shigesato, Yuzo

    2017-02-01

    Indium-tin-zinc oxide (ITZO) films were deposited at various nitrogen flow ratios using magnetron sputtering. At a nitrogen flow ratio of 40%, the structure of ITZO film changed from amorphous, with a short-range-ordered In2O3 phase, to a c-axis oriented InN polycrystalline phase, where InN starts to nucleate from an amorphous In2O3 matrix. Whereas, nitrogen addition had no obvious effect on the structure of indium-gallium-zinc oxide (IGZO) films even at a nitrogen flow ratio of 100%. Nitrogen addition also suppressed the formation of oxygen-related vacancies in ITZO films when the nitrogen flow ratio was less than 20%, and higher nitrogen addition led to an increase in carrier density. Moreover, a red-shift in the optical band edge was observed as the nitrogen flow ratio increased, which could be attributed to the generation of InN crystallites. We anticipate that the present findings demonstrating nitrogen-addition induced structural changes can help to understand the environment-dependent instability in amorphous IGZO or ITZO based thin-film transistors (TFTs).

  6. Nitric oxide synthesis in patients with advanced HIV infection.

    PubMed Central

    Evans, T G; Rasmussen, K; Wiebke, G; Hibbs, J B

    1994-01-01

    The discovery that humans produce nitric oxide and that this molecule plays an important role in cell communication, host resistance to infection, and perhaps in host defence to neoplastic disease, has created much interest in further research on its function in the body. A cytokine-inducible high output L-arginine/nitric oxide pathway was recently detected in patients with advanced malignancy treated with IL-2. The production of nitric oxide was thus examined in patients with advanced HIV infection and in intensive care unit control patients. Extrinsic nitrate and nitrite consumption were carefully controlled in the diet or through the use of total parenteral nutrition. Seven of eight HIV+ patients were placed into positive nitrogen balance. Nitric oxide synthesis was found to be within the normal human range. In contrast, nitric oxide synthesis in extremely ill intensive care unit patients was low normal to depressed. PMID:8033424

  7. 40 CFR 52.1174 - Control strategy: Ozone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... oxides of nitrogen requirements for conformity and new source review. Theses are required by sections 176... architectural, industrial, and maintenance coatings rule; auto body refinisher self-certification audit program... architectural, industrial, and maintenance coatings rule; auto body refinisher self-certification audit program...

  8. 40 CFR 52.1174 - Control strategy: Ozone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... oxides of nitrogen requirements for conformity and new source review. Theses are required by sections 176... architectural, industrial, and maintenance coatings rule; auto body refinisher self-certification audit program... architectural, industrial, and maintenance coatings rule; auto body refinisher self-certification audit program...

  9. 40 CFR 52.1174 - Control strategy: Ozone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... oxides of nitrogen requirements for conformity and new source review. Theses are required by sections 176... architectural, industrial, and maintenance coatings rule; auto body refinisher self-certification audit program... architectural, industrial, and maintenance coatings rule; auto body refinisher self-certification audit program...

  10. 40 CFR 52.1174 - Control strategy: Ozone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... oxides of nitrogen requirements for conformity and new source review. Theses are required by sections 176... architectural, industrial, and maintenance coatings rule; auto body refinisher self-certification audit program... architectural, industrial, and maintenance coatings rule; auto body refinisher self-certification audit program...

  11. 40 CFR 52.1174 - Control strategy: Ozone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... oxides of nitrogen requirements for conformity and new source review. Theses are required by sections 176... architectural, industrial, and maintenance coatings rule; auto body refinisher self-certification audit program... architectural, industrial, and maintenance coatings rule; auto body refinisher self-certification audit program...

  12. The Automobile and Air Pollution: A Chemical Review of the Problem

    ERIC Educational Resources Information Center

    Wildeman, Thomas R.

    1974-01-01

    Summarizes chemical principles underlying the operation of automobiles and the cause of air pollution, including concentrations of carbon monoxide, unburned hydrocarbons, and oxides of nitrogen. Comments and opinions are made concerning present and future pollution control devices. (CC)

  13. INTERNATIONAL APPROACHES TO DEVELOPING STANDARDS FOR NONCRITERIA POLLUTANTS

    EPA Science Inventory

    Much of the initial interest in the control of pollutants, both in the United States and abroad, focused on such "traditional" pollutants as sulfur dioxide, particulate matter, Total Suspended Particulate (TSP) and particulate matter, nitrogen oxides, carbon monoxide, ozone, and ...

  14. “Transference Ratios” to Predict Total Oxidized Sulfur and Nitrogen Deposition – Part I, Monitoring Results

    EPA Science Inventory

    Use of model-predicted “transference ratios” is currently under consideration by the US EPA in the formulation of a Secondary National Ambient Air Quality Standard for oxidized nitrogen and oxidized sulfur. This term is an empirical parameter defined for oxidized sulfur (TS)as th...

  15. Effect of feed-gas humidity on nitrogen atmospheric-pressure plasma jet for biological applications.

    PubMed

    Stephan, Karl D; McLean, Robert J C; DeLeon, Gian; Melnikov, Vadim

    2016-11-14

    We investigate the effect of feed-gas humidity on the oxidative properties of an atmospheric-pressure plasma jet using nitrogen gas. Plasma jets operating at atmospheric pressure are finding uses in medical and biological settings for sterilization and other applications involving oxidative stress applied to organisms. Most jets use noble gases, but some researchers use less expensive nitrogen gas. The feed-gas water content (humidity) has been found to influence the performance of noble-gas plasma jets, but has not yet been systematically investigated for jets using nitrogen gas. Low-humidity and high-humidity feed gases were used in a nitrogen plasma jet, and the oxidation effect of the jet was measured quantitatively using a chemical dosimeter known as FBX (ferrous sulfate-benzoic acid-xylenol orange). The plasma jet using high humidity was found to have about ten times the oxidation effect of the low-humidity jet, as measured by comparison with the addition of measured amounts of hydrogen peroxide to the FBX dosimeter. Atmospheric-pressure plasma jets using nitrogen as a feed gas have a greater oxidizing effect with a high level of humidity added to the feed gas.

  16. Evaluation of Toxic Effects of Aeration and Trichloroethylene Oxidation on Methanotrophic Bacteria Grown with Different Nitrogen Sources

    PubMed Central

    Chu, Kung-Hui; Alvarez-Cohen, Lisa

    1999-01-01

    In this study we evaluated specific and nonspecific toxic effects of aeration and trichloroethylene (TCE) oxidation on methanotrophic bacteria grown with different nitrogen sources (nitrate, ammonia, and molecular nitrogen). The specific toxic effects, exerted directly on soluble methane monooxygenase (sMMO), were evaluated by comparing changes in methane uptake rates and naphthalene oxidation rates following aeration and/or TCE oxidation. Nonspecific toxic effects, defined as general cellular damage, were examined by using a combination of epifluorescent cellular stains to measure viable cell numbers based on respiratory activity and measuring formate oxidation activities following aeration and TCE transformation. Our results suggest that aeration damages predominantly sMMO rather than other general cellular components, whereas TCE oxidation exerts a broad range of toxic effects that damage both specific and nonspecific cellular functions. TCE oxidation caused sMMO-catalyzed activity and respiratory activity to decrease linearly with the amount of substrate degraded. Severe TCE oxidation toxicity resulted in total cessation of the methane, naphthalene, and formate oxidation activities and a 95% decrease in the respiratory activity of methanotrophs. The failure of cells to recover even after 7 days of incubation with methane suggests that cellular recovery following severe TCE product toxicity is not always possible. Our evidence suggests that generation of greater amounts of sMMO per cell due to nitrogen fixation may be responsible for enhanced TCE oxidation activities of nitrogen-fixing methanotrophs rather than enzymatic protection mechanisms associated with the nitrogenase enzymes. PMID:9925614

  17. Rational design of metal nitride redox materials for solar-driven ammonia synthesis.

    PubMed

    Michalsky, Ronald; Pfromm, Peter H; Steinfeld, Aldo

    2015-06-06

    Fixed nitrogen is an essential chemical building block for plant and animal protein, which makes ammonia (NH3) a central component of synthetic fertilizer for the global production of food and biofuels. A global project on artificial photosynthesis may foster the development of production technologies for renewable NH3 fertilizer, hydrogen carrier and combustion fuel. This article presents an alternative path for the production of NH3 from nitrogen, water and solar energy. The process is based on a thermochemical redox cycle driven by concentrated solar process heat at 700-1200°C that yields NH3 via the oxidation of a metal nitride with water. The metal nitride is recycled via solar-driven reduction of the oxidized redox material with nitrogen at atmospheric pressure. We employ electronic structure theory for the rational high-throughput design of novel metal nitride redox materials and to show how transition-metal doping controls the formation and consumption of nitrogen vacancies in metal nitrides. We confirm experimentally that iron doping of manganese nitride increases the concentration of nitrogen vacancies compared with no doping. The experiments are rationalized through the average energy of the dopant d-states, a descriptor for the theory-based design of advanced metal nitride redox materials to produce sustainable solar thermochemical ammonia.

  18. Rational design of metal nitride redox materials for solar-driven ammonia synthesis

    PubMed Central

    Michalsky, Ronald; Pfromm, Peter H.; Steinfeld, Aldo

    2015-01-01

    Fixed nitrogen is an essential chemical building block for plant and animal protein, which makes ammonia (NH3) a central component of synthetic fertilizer for the global production of food and biofuels. A global project on artificial photosynthesis may foster the development of production technologies for renewable NH3 fertilizer, hydrogen carrier and combustion fuel. This article presents an alternative path for the production of NH3 from nitrogen, water and solar energy. The process is based on a thermochemical redox cycle driven by concentrated solar process heat at 700–1200°C that yields NH3 via the oxidation of a metal nitride with water. The metal nitride is recycled via solar-driven reduction of the oxidized redox material with nitrogen at atmospheric pressure. We employ electronic structure theory for the rational high-throughput design of novel metal nitride redox materials and to show how transition-metal doping controls the formation and consumption of nitrogen vacancies in metal nitrides. We confirm experimentally that iron doping of manganese nitride increases the concentration of nitrogen vacancies compared with no doping. The experiments are rationalized through the average energy of the dopant d-states, a descriptor for the theory-based design of advanced metal nitride redox materials to produce sustainable solar thermochemical ammonia. PMID:26052421

  19. Altered nitrogen balance and decreased urea excretion in male rats fed cafeteria diet are related to arginine availability.

    PubMed

    Sabater, David; Agnelli, Silvia; Arriarán, Sofía; Fernández-López, José-Antonio; Romero, María del Mar; Alemany, Marià; Remesar, Xavier

    2014-01-01

    Hyperlipidic diets limit glucose oxidation and favor amino acid preservation, hampering the elimination of excess dietary nitrogen and the catabolic utilization of amino acids. We analyzed whether reduced urea excretion was a consequence of higher NO x ; (nitrite, nitrate, and other derivatives) availability caused by increased nitric oxide production in metabolic syndrome. Rats fed a cafeteria diet for 30 days had a higher intake and accumulation of amino acid nitrogen and lower urea excretion. There were no differences in plasma nitrate or nitrite. NO(x) and creatinine excretion accounted for only a small part of total nitrogen excretion. Rats fed a cafeteria diet had higher plasma levels of glutamine, serine, threonine, glycine, and ornithine when compared with controls, whereas arginine was lower. Liver carbamoyl-phosphate synthetase I activity was higher in cafeteria diet-fed rats, but arginase I was lower. The high carbamoyl-phosphate synthetase activity and ornithine levels suggest activation of the urea cycle in cafeteria diet-fed rats, but low arginine levels point to a block in the urea cycle between ornithine and arginine, thereby preventing the elimination of excess nitrogen as urea. The ultimate consequence of this paradoxical block in the urea cycle seems to be the limitation of arginine production and/or availability.

  20. Altered Nitrogen Balance and Decreased Urea Excretion in Male Rats Fed Cafeteria Diet Are Related to Arginine Availability

    PubMed Central

    Sabater, David; Arriarán, Sofía; Fernández-López, José-Antonio; Romero, María del Mar; Remesar, Xavier

    2014-01-01

    Hyperlipidic diets limit glucose oxidation and favor amino acid preservation, hampering the elimination of excess dietary nitrogen and the catabolic utilization of amino acids. We analyzed whether reduced urea excretion was a consequence of higher NOx; (nitrite, nitrate, and other derivatives) availability caused by increased nitric oxide production in metabolic syndrome. Rats fed a cafeteria diet for 30 days had a higher intake and accumulation of amino acid nitrogen and lower urea excretion. There were no differences in plasma nitrate or nitrite. NOx and creatinine excretion accounted for only a small part of total nitrogen excretion. Rats fed a cafeteria diet had higher plasma levels of glutamine, serine, threonine, glycine, and ornithine when compared with controls, whereas arginine was lower. Liver carbamoyl-phosphate synthetase I activity was higher in cafeteria diet-fed rats, but arginase I was lower. The high carbamoyl-phosphate synthetase activity and ornithine levels suggest activation of the urea cycle in cafeteria diet-fed rats, but low arginine levels point to a block in the urea cycle between ornithine and arginine, thereby preventing the elimination of excess nitrogen as urea. The ultimate consequence of this paradoxical block in the urea cycle seems to be the limitation of arginine production and/or availability. PMID:24707502

  1. Multi-omics analysis reveals regulators of the response to nitrogen limitation in Yarrowia lipolytica.

    PubMed

    Pomraning, Kyle R; Kim, Young-Mo; Nicora, Carrie D; Chu, Rosalie K; Bredeweg, Erin L; Purvine, Samuel O; Hu, Dehong; Metz, Thomas O; Baker, Scott E

    2016-02-25

    Yarrowia lipolytica is an oleaginous ascomycete yeast that stores lipids in response to limitation of nitrogen. While the enzymatic pathways responsible for neutral lipid accumulation in Y. lipolytica are well characterized, regulation of these pathways has received little attention. We therefore sought to characterize the response to nitrogen limitation at system-wide levels, including the proteome, phosphoproteome and metabolome, to better understand how this organism regulates and controls lipid metabolism and to identify targets that may be manipulated to improve lipid yield. We found that ribosome structural genes are down-regulated under nitrogen limitation, during which nitrogen containing compounds (alanine, putrescine, spermidine and urea) are depleted and sugar alcohols and TCA cycle intermediates accumulate (citrate, fumarate and malate). We identified 1219 novel phosphorylation sites in Y. lipolytica, 133 of which change in their abundance during nitrogen limitation. Regulatory proteins, including kinases and DNA binding proteins, are particularly enriched for phosphorylation. Within lipid synthesis pathways, we found that ATP-citrate lyase, acetyl-CoA carboxylase and lecithin cholesterol acyl transferase are phosphorylated during nitrogen limitation while many of the proteins involved in β-oxidation are down-regulated, suggesting that storage lipid accumulation may be regulated by phosphorylation of key enzymes. Further, we identified short DNA elements that associate specific transcription factor families with up- and down-regulated genes. Integration of metabolome, proteome and phosphoproteome data identifies lipid accumulation in response to nitrogen limitation as a two-fold result of increased production of acetyl-CoA from excess citrate and decreased capacity for β-oxidation.

  2. High temperature decomposition of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2004-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO.sub.2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  3. High temperature decomposition of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2011-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO.sub.2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  4. Decomposition of nitric oxide in a hot nitrogen stream to synthesize air for hypersonic wind tunnel combustion testing

    NASA Technical Reports Server (NTRS)

    Zumdieck, J. F.; Zlatarich, S. A.

    1974-01-01

    A clean source of high enthalpy air was obtained from the exothermic decomposition of nitric oxide in the presence of strongly heated nitrogen. A nitric oxide jet was introduced into a confined coaxial nitrogen stream. Measurements were made of the extent of mixing and reaction. Experimental results are compared with one- and two-dimensional chemical kinetics computations. Both analyses predict much lower reactivity than was observed experimentally. Inlet nitrogen temperatures above 2400 K were sufficient to produce experimentally a completely reacted gas stream of synthetic air.

  5. Nitrogen Oxide Fluxes and Nitrogen Cycling during Postagricultural Succession and Forest Fertilization in the Humid Tropics.

    Treesearch

    Heather Erickson; Michael Keller; Eric Davidson

    2001-01-01

    The effects of changes in tropical land use on soil emissions of nitrous oxide (N2O) and nitric oxide (NO) are not well understood. We examined emissions of N2O and NO and their relationships to land use and forest composition, litterfall, soil nitrogen (N) pools and turnover, soil moisture, and patterns of carbon (C) cycling in a lower montane, subtropical wet region...

  6. Kinetics of the formation of ozone and nitrogen oxides due to a pulsed microwave discharge in air

    NASA Astrophysics Data System (ADS)

    Larin, V. F.; Rumiantsev, S. A.

    1989-03-01

    The paper presents results of a numerical simulation of the kinetics of plasma-chemical processes induced by a single microwave pulse in the stratosphere. It is shown that the gas temperature is one of the main factors influencing the concentration ratio of ozone and nitrogen oxides formed under the effect of a microwave pulse. Long pulses, producing considerable gas heating, favor the formation of nitrogen oxides.

  7. 77 FR 60904 - Air Quality Implementation Plans; Alabama; Attainment Plan for the Alabama Portion of the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-05

    ... available control technology (RACT) and reasonably available control measures (RACM); reasonable further... determination for PM 2.5 and nitrogen oxides (NO X ) for the mobile source contribution to ambient PM 2.5 levels..., an RFP plan, contingency measures, and an insignificance determination for mobile direct PM 2.5 and...

  8. 77 FR 67322 - Revisions to the California State Implementation Plan, Placer County Air Pollution Control District

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-09

    ... Implementation Plan (SIP). These revisions concern oxides of nitrogen (NOx) emissions from biomass boilers. We... PCAPCD 233 Biomass Boilers 06/14/12 09/21/12 On October 11, 2012, EPA determined that the submittal for... that control NO X emissions. Rule 233 limits NO X emissions from biomass boilers. EPA's technical...

  9. Regime Shift and Microbial Dynamics in a Sequencing Batch Reactor for Nitrification and Anammox Treatment of Urine ▿†

    PubMed Central

    Bürgmann, Helmut; Jenni, Sarina; Vazquez, Francisco; Udert, Kai M.

    2011-01-01

    The microbial population and physicochemical process parameters of a sequencing batch reactor for nitrogen removal from urine were monitored over a 1.5-year period. Microbial community fingerprinting (automated ribosomal intergenic spacer analysis), 16S rRNA gene sequencing, and quantitative PCR on nitrogen cycle functional groups were used to characterize the microbial population. The reactor combined nitrification (ammonium oxidation)/anammox with organoheterotrophic denitrification. The nitrogen elimination rate initially increased by 400%, followed by an extended period of performance degradation. This phase was characterized by accumulation of nitrite and nitrous oxide, reduced anammox activity, and a different but stable microbial community. Outwashing of anammox bacteria or their inhibition by oxygen or nitrite was insufficient to explain reactor behavior. Multiple lines of evidence, e.g., regime-shift analysis of chemical and physical parameters and cluster and ordination analysis of the microbial community, indicated that the system had experienced a rapid transition to a new stable state that led to the observed inferior process rates. The events in the reactor can thus be interpreted to be an ecological regime shift. Constrained ordination indicated that the pH set point controlling cycle duration, temperature, airflow rate, and the release of nitric and nitrous oxides controlled the primarily heterotrophic microbial community. We show that by combining chemical and physical measurements, microbial community analysis and ecological theory allowed extraction of useful information about the causes and dynamics of the observed process instability. PMID:21724875

  10. Electrochemistry and spectroelectrochemistry of bioactive hydroxyquinolines: a mechanistic study.

    PubMed

    Sokolová, Romana; Nycz, Jacek E; Ramešová, Šárka; Fiedler, Jan; Degano, Ilaria; Szala, Marcin; Kolivoška, Viliam; Gál, Miroslav

    2015-05-21

    The oxidation mechanism of selected hydroxyquinoline carboxylic acids such as 8-hydroxyquinoline-7-carboxylic acid (1), the two positional isomers 2-methyl-8-hydroxyquinoline-7-carboxylic acid (3) and 2-methyl-5-hydroxyquinoline-6-carboxylic acid (4), as well as other hydroxyquinolines were studied in aprotic environment using cyclic voltammetry, controlled potential electrolysis, in situ UV-vis and IR spectroelectrochemistry, and HPLC-MS/MS techniques. IR spectroelectrochemistry showed that oxidation unexpectedly proceeds together with protonation of the starting compound. We proved that the nitrogen atom in the heterocycle of hydroxyquinolines is protonated during the apparent 0.7 electron oxidation process. This was rationalized by the autodeprotonation reaction by another two starting molecules of hydroxyquinoline, so that the overall oxidation mechanism involves two electrons and three starting molecules. Both the electrochemical and spectroelectrochemical results showed that the oxidation mechanism is not influenced by the presence of the carboxylic group in the chemical structure of hydroxyquinolines, as results from oxidation of 2,7-dimethyl-5-hydroxyquinoline (6). In the presence of a strong proton acceptor such as pyridine, the oxidation ECEC process involves two electrons and two protons per one molecule of the hydroxyquinoline derivative. The electron transfer efficiency of hydroxyquinolines in biosystems may be related to protonation of biocompounds containing nitrogen bases. Molecular orbital calculations support the experimental findings.

  11. 40 CFR 52.326 - Area-wide nitrogen oxides (NOX) exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Area-wide nitrogen oxides (NOX) exemptions. 52.326 Section 52.326 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Colorado § 52.326 Area-wide nitrogen...

  12. 40 CFR 52.326 - Area-wide nitrogen oxides (NOX) exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Area-wide nitrogen oxides (NOX) exemptions. 52.326 Section 52.326 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Colorado § 52.326 Area-wide nitrogen...

  13. 40 CFR 52.326 - Area-wide nitrogen oxides (NOX) exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 3 2012-07-01 2012-07-01 false Area-wide nitrogen oxides (NOX) exemptions. 52.326 Section 52.326 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Colorado § 52.326 Area-wide nitrogen...

  14. 40 CFR 52.326 - Area-wide nitrogen oxides (NOX) exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Area-wide nitrogen oxides (NOX) exemptions. 52.326 Section 52.326 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Colorado § 52.326 Area-wide nitrogen...

  15. 40 CFR 52.326 - Area-wide nitrogen oxides (NOX) exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Area-wide nitrogen oxides (NOX) exemptions. 52.326 Section 52.326 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Colorado § 52.326 Area-wide nitrogen...

  16. 40 CFR 86.223-94 - Oxides of nitrogen analyzer calibration.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Oxides of nitrogen analyzer calibration. 86.223-94 Section 86.223-94 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... nitrogen analyzer calibration. The provisions of § 86.123-78 apply to this subpart if NOX measurements are...

  17. 40 CFR 86.223-94 - Oxides of nitrogen analyzer calibration.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Oxides of nitrogen analyzer calibration. 86.223-94 Section 86.223-94 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... nitrogen analyzer calibration. The provisions of § 86.123-78 apply to this subpart if NOX measurements are...

  18. 40 CFR 86.223-94 - Oxides of nitrogen analyzer calibration.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 19 2013-07-01 2013-07-01 false Oxides of nitrogen analyzer calibration. 86.223-94 Section 86.223-94 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... nitrogen analyzer calibration. The provisions of § 86.123-78 apply to this subpart if NOX measurements are...

  19. Draft Plan for Development of the Integrated Science Assessment for Nitrogen Oxides - Health Criteria

    EPA Science Inventory

    EPA has announced a draft development plan for the next Integrated Science Assessment (ISA) for the health effects of nitrogen oxides (NOX) which will serve as the scientific basis for review of the primary (health-based) National Ambient Air Quality Standard for nitrogen dioxide...

  20. Robust p-type doping of copper oxide using nitrogen implantation

    NASA Astrophysics Data System (ADS)

    Jorge, Marina; Polyakov, Stanislav M.; Cooil, Simon; Schenk, Alex K.; Edmonds, Mark; Thomsen, Lars; Mazzola, Federico; Wells, Justin W.

    2017-07-01

    We demonstrate robust p-type doping of Cu2O using low/medium energy ion implantation. Samples are made by controlled oxidation of annealed Cu metal foils, which results in Cu2O with levels of doping close to intrinsic. Samples are then implanted with nitrogen ions using a kinetic energy in the few keV range. Using this method, we are able to produce very high levels of doping, as evidenced by a 350 meV shift in the Fermi level towards the VB maximum. The robustness of the nitrogen implanted samples are tested by exposing them to atmospheric contaminants, and elevated temperatures. The samples are found to survive an increase in temperature of many hundreds of degrees. The robustness of the samples, combined with the fact that the materials used are safe, abundant and non-toxic and that the methods used for the growth of Cu2O and N+ implantation are simple and cheap to implement industrially, underlines the potential of Cu2O:N for affordable intermediate band photovoltaics.

  1. Synergistic Effect of Nitrogen and Refractory Material on TiN Formation and Equiaxed Grain Structure of Ferritic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Lee, Mun Hyung; Park, Joo Hyun

    2018-06-01

    The effect of nitrogen content on the formation of an equiaxed solidification structure of Fe-16Cr steel was investigated. Moreover, two different kinds of refractory materials, i.e., alumina and magnesia, were employed to control the type of oxide inclusion. The characteristics of TiN(-oxide) inclusions were quantitatively analyzed in both molten steel and solidified samples. When the melting was carried out in the alumina refractory, the grain size continuously decreased with increasing nitrogen content. However, a minimum grain size was observed at a specific nitrogen content (approx. 150 ppm) when the steel was melted in the magnesia refractory. Most of the single TiN particles had a cuboidal shape and fine irregularly shaped particles were located along the grain boundary due to the microsegregation of Ti at the grain boundary during solidification. The type of TiN-oxide hybrid inclusion was strongly affected by the refractory material where Al2O3-TiN and MgAl2O4-TiN hybrid-type inclusions were obtained in the alumina and magnesia refractory experiments, respectively. The formation of oxide inclusions was well predicted by thermochemical computations and it was commonly found that oxide particles were initially formed, followed by the nucleation and growth of TiN. When the nitrogen content increased, the number density of TiN linearly increased in the alumina refractory experiments. However, the number of TiN exhibits a maximum at about [N] = 150 ppm, at which a minimum grain size was obtained in the magnesia refractory experiments. Therefore, the larger the number density of TiN, the smaller the primary grain size after solidification. The number density of TiN in the steel melted in the magnesia refractory was greater than that in the steel melted in the alumina refractory at given Ti and N contents, which was due to the lower planar lattice disregistry of MgAl2O4-TiN interface rather than that of Al2O3-TiN interface. When Δ T TiN (= difference between the TiN precipitation temperature and the liquidus of the steel) was 20 K to 40 K, the number density of effective TiN was maximized and thus, the grain size was minimized after solidification. Finally, although most of the TiN particles were smaller than 1 μm in the molten steel samples irrespective of the nitrogen content, TiN particles larger than 10 μm were observed in the solidified samples when the nitrogen content was greater than 150 ppm. The growth of TiN particles during melting and solidification was well predicted by the combinatorial simulation of the `Ostwald ripening model' based on the Lifshitz-Slyozov-Wagner theory in conjunction with the `Diffusion controlled model' using Ohnaka's microsegregation equation.

  2. Synergistic Effect of Nitrogen and Refractory Material on TiN Formation and Equiaxed Grain Structure of Ferritic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Lee, Mun Hyung; Park, Joo Hyun

    2018-03-01

    The effect of nitrogen content on the formation of an equiaxed solidification structure of Fe-16Cr steel was investigated. Moreover, two different kinds of refractory materials, i.e., alumina and magnesia, were employed to control the type of oxide inclusion. The characteristics of TiN(-oxide) inclusions were quantitatively analyzed in both molten steel and solidified samples. When the melting was carried out in the alumina refractory, the grain size continuously decreased with increasing nitrogen content. However, a minimum grain size was observed at a specific nitrogen content (approx. 150 ppm) when the steel was melted in the magnesia refractory. Most of the single TiN particles had a cuboidal shape and fine irregularly shaped particles were located along the grain boundary due to the microsegregation of Ti at the grain boundary during solidification. The type of TiN-oxide hybrid inclusion was strongly affected by the refractory material where Al2O3-TiN and MgAl2O4-TiN hybrid-type inclusions were obtained in the alumina and magnesia refractory experiments, respectively. The formation of oxide inclusions was well predicted by thermochemical computations and it was commonly found that oxide particles were initially formed, followed by the nucleation and growth of TiN. When the nitrogen content increased, the number density of TiN linearly increased in the alumina refractory experiments. However, the number of TiN exhibits a maximum at about [N] = 150 ppm, at which a minimum grain size was obtained in the magnesia refractory experiments. Therefore, the larger the number density of TiN, the smaller the primary grain size after solidification. The number density of TiN in the steel melted in the magnesia refractory was greater than that in the steel melted in the alumina refractory at given Ti and N contents, which was due to the lower planar lattice disregistry of MgAl2O4-TiN interface rather than that of Al2O3-TiN interface. When ΔT TiN (= difference between the TiN precipitation temperature and the liquidus of the steel) was 20 K to 40 K, the number density of effective TiN was maximized and thus, the grain size was minimized after solidification. Finally, although most of the TiN particles were smaller than 1 μm in the molten steel samples irrespective of the nitrogen content, TiN particles larger than 10 μm were observed in the solidified samples when the nitrogen content was greater than 150 ppm. The growth of TiN particles during melting and solidification was well predicted by the combinatorial simulation of the `Ostwald ripening model' based on the Lifshitz-Slyozov-Wagner theory in conjunction with the `Diffusion controlled model' using Ohnaka's microsegregation equation.

  3. Reactive nitrogen deposition to South East Asian rainforest

    NASA Astrophysics Data System (ADS)

    di Marco, Chiara F.; Phillips, Gavin J.; Thomas, Rick; Tang, Sim; Nemitz, Eiko; Sutton, Mark A.; Fowler, David; Lim, Sei F.

    2010-05-01

    The supply of reactive nitrogen (N) to global terrestrial ecosystems has doubled since the 1960s as a consequence of human activities, such as fertilizer application and production of nitrogen oxides by fossil-fuel burning. The deposition of atmospheric N species constitutes a major nutrient input to the biosphere. Tropical forests have been undergoing a radical land use change by increasing cultivation of sugar cane and oil palms and the remaining forests are increasingly affected by anthropogenic activities. Yet, quantifications of atmospheric nitrogen deposition to tropical forests, and nitrogen cycling under near-pristine and polluted conditions are rare. The OP3 project ("Oxidant and Particle Photochemical Processes above a Southeast Asian Tropical Rainforest") was conceived to study how emissions of reactive trace gases from a tropical rain forest mediate the regional scale production and processing of oxidants and particles, and to better understand the impact of these processes on local, regional and global scale atmospheric composition, chemistry and climate. As part of this study we have measured reactive, nitrogen containing trace gas (ammonia, nitric acid) and the associated aerosol components (ammonium, nitrate) at monthly time resolution using a simple filter / denuder for 16 months. These measurements were made at the Bukit Atur Global Atmospheric Watch tower near Danum Valley in the Malaysian state of Sabah, Borneo. In addition, the same compounds were measured at hourly time-resolution during an intensive measurement period, with a combination of a wet-chemistry system based on denuders and steam jet aerosol collectors and an aerosol mass spectrometer (HR-ToF-AMS), providing additional information on the temporal controls. During this period, concentrations and fluxes of NO, NO2 and N2O were also measured. The measurements are used for inferential dry deposition modelling and combined with wet deposition data from the South East Asian Acid Deposition Network to estimate the total annual atmospheric reactive nitrogen deposition to this tropical forest ecosystem and to quantify the relative contribution of the different chemical compounds.

  4. [Achievement of Sulfate-Reducing Anaerobic Ammonium Oxidation Reactor Started with Nitrate-Reducting Anaerobic Ammonium Oxidation].

    PubMed

    Liu, Zheng-chuan; Yuan, Lin-jiang; Zhou, Guo-biao; Li, Jing

    2015-09-01

    The transformation of nitrite-reducing anaerobic ammonium oxidation to sulfate-reducing anaerobic ammonium oxidation in an UASB was performed and the changes in microbial community were studied. The result showed that the sulfate reducing anaerobic ammonium oxidation process was successfully accomplished after 177 days' operation. The removal rate of ammonium nitrogen and sulfate were up to 58. 9% and 15. 7%, the removing load of ammonium nitrogen and sulfate were 74. 3 mg.(L.d)-1 and 77. 5 mg.(L.d)-1 while concentration of ammonium nitrogen and sulfate of influent were 130 mg.(L.d)-1 and 500 mg.(L.d)-1, respectively. The lost nitrogen and sulphur was around 2 in molar ratio. The pH value of the effluent was lower than that of the influent. Instead of Candidatus brocadia in nitrite reducing anaerobic ammonium oxidation granular sludge, Bacillus benzoevorans became the dominant species in sulfate reducing anaerobic ammonium oxidation sludge. The dominant bacterium in the two kinds of anaerobic ammonium oxidation process is different. Our results imply that the two anaerobic ammonium oxidation processes are carried out by different kind of bacterium.

  5. Process for Nitrogen Oxide Waste Conversion to Fertilizer

    NASA Technical Reports Server (NTRS)

    Lueck, Dale E. (Inventor); Parrish, Clyde F. (Inventor)

    2003-01-01

    The present invention describes a process for converting vapor streams from sources containing at least one nitrogen-containing oxidizing agent therein to a liquid fertilizer composition comprising the steps of: a) directing a vapor stream containing at least one nitrogen-containing oxidizing agent to a first contact zone; b) contacting said vapor stream with water to form nitrogen oxide(s) from said at least one nitrogen-containing oxidizing agent; c) directing said acid(s) as a second stream to a second contact zone; d) exposing said second stream to hydrogen peroxide which is present within said second contact zone in a relative amount of at least 0.1% by weight of said second stream within said second contact zone to convert at least some of any nitrogen oxide species or ions other than in the nitrate form present within said second stream to nitrate ion; e) sampling said stream within said second contact zone to determine the relative amount of hydrogen peroxide within said second contact zone; f) adding hydrogen peroxide to said second contact zone when a level of hydrogen peroxide less than 0.1 % by weight in said second stream is determined by said sampling; g) adding a solution comprising potassium hydroxide to said second stream to maintain a pH between 6.0 and 11.0 within said second stream within said second contact zone to form a solution of potassium nitrate; and h) removing said solution of potassium nitrate from said second contact zone.

  6. Process and Equipment for Nitrogen Oxide Waste Conversion to Fertilizer

    NASA Technical Reports Server (NTRS)

    Lueck, Dale E. (Inventor); Parrish, Clyde F. (Inventor)

    2000-01-01

    The present invention describes a process for converting vapor streams from sources containing at least one nitrogen-containing oxidizing agent therein to a liquid fertilizer composition comprising the steps of: (1) directing a vapor stream containing at least nitrogen-containing oxidizing agent to a first contact zone; (2) contacting said vapor stream with water to form nitrogen oxide(s) from said at least one nitrogen- containing oxidizing agent; (3) directing said acid(s) as a second stream to a second contact zone; (4) exposing said second stream to hydrogen peroxide which is present within said second contact zone in a relative amount of at least 0.1% by weight of said second stream within said second contact zone to convert at least some of any nitrogen oxide species or ions other than in the nitrite form present within said second stream to nitrate ion; (5) sampling said stream within said second contact zone to determine the relative amount of hydrogen peroxide within said second contact zone; (6) adding hydrogen peroxide to said second contact zone when a level on hydrogen peroxide less than 0.1% by weight in said second stream is determined by said sampling; (7) adding a solution comprising potassium hydroxide to said second stream to maintain a pH between 6.0 and 11.0 within said second stream within said second contact zone to form a solution of potassium nitrate; and (8) removing sais solution of potassium nitrate from said second contact zone.

  7. 40 CFR 52.1621 - Classification of regions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) New Mexico § 52.1621 Classification of regions. The New Mexico plan was evaluated on the basis of the following classifications: Air quality control region Pollutant Particulate matter Sulfur oxides Nitrogen dioxide Carbon monoxide Ozone...

  8. 40 CFR 52.1621 - Classification of regions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) New Mexico § 52.1621 Classification of regions. The New Mexico plan was evaluated on the basis of the following classifications: Air quality control region Pollutant Particulate matter Sulfur oxides Nitrogen dioxide Carbon monoxide Ozone...

  9. A series of inorganic solid nitrogen sources for the synthesis of metal nitride clusterfullerenes: the dependence of production yield on the oxidation state of nitrogen and counter ion.

    PubMed

    Liu, Fupin; Guan, Jian; Wei, Tao; Wang, Song; Jiao, Mingzhi; Yang, Shangfeng

    2013-04-01

    A series of nitrogen-containing inorganic solid compounds with variable oxidation states of nitrogen and counter ions have been successfully applied as new inorganic solid nitrogen sources toward the synthesis of Sc-based metal nitride clusterfullerenes (Sc-NCFs), including ammonium salts [(NH4)xH(3-x)PO4 (x = 0-2), (NH4)2SO4, (NH4)2CO3, NH4X (X = F, Cl), NH4SCN], thiocyanate (KSCN), nitrates (Cu(NO3)2, NaNO3), and nitrite (NaNO2). Among them, ammonium phosphates ((NH4)xH(3-x)PO4, x = 1-3) and ammonium thiocyanate (NH4SCN) are revealed to behave as better nitrogen sources than others, and the highest yield of Sc-NCFs is achieved when NH4SCN was used as a nitrogen source. The optimum molar ratio of Sc2O3:(NH4)3PO4·3H2O:C and Sc2O3:NH4SCN:C has been determined to be 1:2:15 and 1:3:15, respectively. The thermal decomposition products of these 12 inorganic compounds have been discussed in order to understand their different performances toward the synthesis of Sc-NCFs, and accordingly the dependence of the production yield of Sc-NCFs on the oxidation state of nitrogen and counter ion is interpreted. The yield of Sc3N@C80 (I(h) + D(5h)) per gram Sc2O3 by using the N2-based group of nitrogen sources (thiocyanate, nitrates, and nitrite) is overall much lower than those by using gaseous N2 and NH4SCN, indicating the strong dependence of the yield of Sc-NCFs on the oxidation state of nitrogen, which is attributed to the "in-situ" redox reaction taking place for the N2-based group of nitrogen sources during discharging. For NH3-based group of nitrogen sources (ammonium salts) which exhibits a (-3) oxidation states of nitrogen, their performance as nitrogen sources is found to be sensitively dependent on the anion, and this is understood by considering their difference on the thermal stability and/or decomposition rate. Contrarily, for the N2-based group of nitrogen sources, the formation of Sc-NCFs is independent to both the oxidation state of nitrogen (+3 or +5) and the cation.

  10. Register of specialized sources for information on selected fuels and oxidizers. [rocket propellants, bibliographies

    NASA Technical Reports Server (NTRS)

    Ludtke, P. R.

    1975-01-01

    Thirty-eight (38) organizations are listed and described that catalog and file information in their data systems on fuel and oxidizers. The fuels include hydrogen, methane and hydrazine-type fuels; the oxidizers include oxygen, fluorine, flox, nitrogen tetroxide and ozone. The type of available information covers thermophysical properties, propellant systems, propellant fires-control-extinguishment, propellant explosions, propellant combustion, propellant safety, and fluorine chemistry. These organizations have assembled and collated their information so that it will be useful in the solution of engineering problems.

  11. On-road, in-use gaseous emission measurements by remote sensing of school buses equipped with diesel oxidation catalysts and diesel particulate filters.

    PubMed

    Burgard, Daniel A; Provinsal, Melissa N

    2009-12-01

    A remote sensing device was used to obtain on-road and in-use gaseous emission measurements from three fleets of schools buses at two locations in Washington State. This paper reports each fleet's carbon monoxide (CO), hydrocarbon (HC), nitric oxide (NO), and nitrogen dioxide (NO2) mean data. The fleets represent current emission retrofit technologies, such as diesel particulate filters and diesel oxidation catalysts, and a control fleet. This study shows that CO and HC emissions decrease with the use of either retrofit technology when compared with control buses of the same initial emission standards. The CO and HC emission reductions are consistent with published U.S. Environmental Protection Agency verified values. The total oxides of nitrogen (NOx), NO, and the NO2/NOx ratio all increase with each retrofit technology when compared with control buses. As was expected, the diesel particulate filters emitted significantly higher levels of NO2 than the control fleet because of the intentional conversion of NO to NO2 by these systems. Most prior research suggests that NOx emissions are unaffected by the retrofits; however, these previous studies have not included measurements from retrofit devices on-road and after nearly 5 yr of use. Two 2006 model-year buses were also measured. These vehicles did not have retrofit devices but were built to more stringent new engine standards. Reductions in HCs and NOx were observed for these 2006 vehicles in comparison to other non-retrofit earlier model-year vehicles.

  12. Electrochemical process for the preparation of nitrogen fertilizers

    DOEpatents

    Aulich, Ted R [Grand Forks, ND; Olson, Edwin S [Grand Forks, ND; Jiang, Junhua [Grand Forks, ND

    2012-04-10

    The present invention provides methods and apparatus for the preparation of nitrogen fertilizers including ammonium nitrate, urea, urea-ammonium nitrate, and/or ammonia, at low temperature and pressure, preferably at ambient temperature and pressure, utilizing a source of carbon, a source of nitrogen, and/or a source of hydrogen or hydrogen equivalent. Implementing an electrolyte serving as ionic charge carrier, (1) ammonium nitrate is produced via the reduction of a nitrogen source at the cathode and the oxidation of a nitrogen source at the anode; (2) urea or its isomers are produced via the simultaneous cathodic reduction of a carbon source and a nitrogen source; (3) ammonia is produced via the reduction of nitrogen source at the cathode and the oxidation of a hydrogen source or a hydrogen equivalent such as carbon monoxide or a mixture of carbon monoxide and hydrogen at the anode; and (4) urea-ammonium nitrate is produced via the simultaneous cathodic reduction of a carbon source and a nitrogen source, and anodic oxidation of a nitrogen source. The electrolyte can be aqueous, non-aqueous, or solid.

  13. Review of the Secondary National Ambient Air Quality Standard for Nitrogen Oxides, Sulfur Oxides and Particulate Matter: Risk and Exposure Assessment Planning Document

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) is conducting a review of the air quality criteria and the secondary (welfare-based) national ambient air quality standards (NAAQS) for nitrogen oxides (NOx), sulfur oxides (SOx), and particulate matter (PM). The major phases of the ...

  14. A Continuous Flow System for the Measurement of Ambient Nitrogen Oxides [NO + NO2] Using Rhodamine B Hydrazide as a Chemosensor.

    PubMed

    Malingappa, Pandurangappa; Yarradoddappa, Venkataramanappa

    2014-01-01

    A new chemosensor has been used to monitor atmospheric nitrogen oxides [NO + NO2] at parts per billion (ppb) level. It is based on the catalytic reaction of nitrogen oxides with rhodamine B hydrazide (RBH) to produce a colored compound through the hydrolysis of the amide bond of the molecule. A simple colorimeter has been used to monitor atmospheric nitrogen dioxide at ppb level. The air samples were purged through a sampling cuvette containing RBH solution using peristaltic pump. The proposed method has been successfully applied to monitor the ambient nitrogen dioxide levels at traffic junction points within the city limits and the results obtained are compared with the standard Griess-Ilosvay method.

  15. Factors Driving Potential Ammonia Oxidation in Canadian Arctic Ecosystems: Does Spatial Scale Matter?

    PubMed Central

    Banerjee, Samiran

    2012-01-01

    Ammonia oxidation is a major process in nitrogen cycling, and it plays a key role in nitrogen limited soil ecosystems such as those in the arctic. Although mm-scale spatial dependency of ammonia oxidizers has been investigated, little is known about the field-scale spatial dependency of aerobic ammonia oxidation processes and ammonia-oxidizing archaeal and bacterial communities, particularly in arctic soils. The purpose of this study was to explore the drivers of ammonia oxidation at the field scale in cryosols (soils with permafrost within 1 m of the surface). We measured aerobic ammonia oxidation potential (both autotrophic and heterotrophic) and functional gene abundance (bacterial amoA and archaeal amoA) in 279 soil samples collected from three arctic ecosystems. The variability associated with quantifying genes was substantially less than the spatial variability observed in these soils, suggesting that molecular methods can be used reliably evaluate spatial dependency in arctic ecosystems. Ammonia-oxidizing archaeal and bacterial communities and aerobic ammonia oxidation were spatially autocorrelated. Gene abundances were spatially structured within 4 m, whereas biochemical processes were structured within 40 m. Ammonia oxidation was driven at small scales (<1m) by moisture and total organic carbon, whereas gene abundance and other edaphic factors drove ammonia oxidation at medium (1 to 10 m) and large (10 to 100 m) scales. In these arctic soils heterotrophs contributed between 29 and 47% of total ammonia oxidation potential. The spatial scale for aerobic ammonia oxidation genes differed from potential ammonia oxidation, suggesting that in arctic ecosystems edaphic, rather than genetic, factors are an important control on ammonia oxidation. PMID:22081570

  16. Reactive nitrogen oxides in the southeast United States national parks: source identification, origin, and process budget

    NASA Astrophysics Data System (ADS)

    Tong, Daniel Quansong; Kang, Daiwen; Aneja, Viney P.; Ray, John D.

    2005-01-01

    We present in this study both measurement-based and modeling analyses for elucidation of source attribution, influence areas, and process budget of reactive nitrogen oxides at two rural southeast United States sites (Great Smoky Mountains national park (GRSM) and Mammoth Cave national park (MACA)). Availability of nitrogen oxides is considered as the limiting factor to ozone production in these areas and the relative source contribution of reactive nitrogen oxides from point or mobile sources is important in understanding why these areas have high ozone. Using two independent observation-based techniques, multiple linear regression analysis and emission inventory analysis, we demonstrate that point sources contribute a minimum of 23% of total NOy at GRSM and 27% at MACA. The influence areas for these two sites, or origins of nitrogen oxides, are investigated using trajectory-cluster analysis. The result shows that air masses from the West and Southwest sweep over GRSM most frequently, while pollutants transported from the eastern half (i.e., East, Northeast, and Southeast) have limited influence (<10% out of all air masses) on air quality at GRSM. The processes responsible for formation and removal of reactive nitrogen oxides are investigated using a comprehensive 3-D air quality model (Multiscale Air Quality SImulation Platform (MAQSIP)). The NOy contribution associated with chemical transformations to NOz and O3, based on process budget analysis, is as follows: 32% and 84% for NOz, and 26% and 80% for O3 at GRSM and MACA, respectively. The similarity between NOz and O3 process budgets suggests a close association between nitrogen oxides and effective O3 production at these rural locations.

  17. Thermal NF3 fluorination/oxidation of cobalt, yttrium, zirconium, and selected lanthanide oxides

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Scheele, Randall D.; McNamara, Bruce K.; Casella, Andrew M.

    2013-02-01

    This paper presents results of our continuing investigation on the use of nitrogen trifluoride as a fluorination or fluorination/oxidation agent for separating valuable constituents from used nuclear fuels by exploiting the different volatilities of the constituent fission product and actinide fluorides. This article focuses on fission products that do not have volatile fluorides or oxyfluorides at expected operations temperatures. Our thermodynamic calculations show that nitrogen trifluoride has the potential to completely fluorinate fission product oxides to their fluorides. Simultaneous thermogravimetric and differential thermal analyses show that the oxides of cobalt, zirconium, and the lanthanides are fluorinated but do not formmore » volatile fluorides when treated with nitrogen trifluoride at temperatures up to 550°C. Our studies of gadolinium-doped commercial nuclear fuel indicate that nitrogen trifluoride can extract uranium from the non-volatile gadolinium.« less

  18. [Ammonia-oxidizing archaea and their important roles in nitrogen biogeochemical cycling: a review].

    PubMed

    Liu, Jing-Jing; Wu, Wei-Xiang; Ding, Ying; Shi, De-Zhi; Chen, Ying-Xu

    2010-08-01

    As the first step of nitrification, ammonia oxidation is the key process in global nitrogen biogeochemical cycling. So far, the autotrophic ammonia-oxidizing bacteria (AOB) in the beta- and gamma-subgroups of proteobacteria have been considered as the most important contributors to ammonia oxidation, but the recent researches indicated that ammonia-oxidizing archaea (AOA) are widely distributed in various kinds of ecosystems and quantitatively predominant, playing important roles in the global nitrogen biogeochemical cycling. This paper reviewed the morphological, physiological, and ecological characteristics and the molecular phylogenies of AOA, and compared and analyzed the differences and similarities of the ammonia monooxygenase (AMO) and its encoding genes between AOA and AOB. In addition, the potential significant roles of AOA in nitrogen biogeochemical cycling in aquatic and terrestrial ecosystems were summarized, and the future research directions of AOA in applied ecology and environmental protection were put forward.

  19. Lightning NOx and Impacts on Air Quality

    NASA Technical Reports Server (NTRS)

    Murray, Lee T.

    2016-01-01

    Lightning generates relatively large but uncertain quantities of nitrogen oxides, critical precursors for ozone and hydroxyl radical (OH), the primary tropospheric oxidants. Lightning nitrogen oxide strongly influences background ozone and OH due to high ozone production efficiencies in the free troposphere, effecting small but non-negligible contributions to surface pollutant concentrations. Lightning globally contributes 3-4 ppbv of simulated annual-mean policy-relevant background (PRB) surface ozone, comprised of local, regional, and hemispheric components, and up to 18 ppbv during individual events. Feedbacks via methane may counter some of these effects on decadal time scales. Lightning contributes approximately 1 percent to annual-mean surface particulate matter, as a direct precursor and by promoting faster oxidation of other precursors. Lightning also ignites wildfires and contributes to nitrogen deposition. Urban pollution influences lightning itself, with implications for regional lightning-nitrogen oxide production and feedbacks on downwind surface pollution. How lightning emissions will change in a warming world remains uncertain.

  20. Controlled electrochemical doping of graphene-based 3D nanoarchitecture electrodes for supercapacitors and capacitive deionisation.

    PubMed

    Abdelkader, A M; Fray, D J

    2017-10-05

    Chemically-doped graphenes are promising electrode materials for energy storage and electrosorption applications. Here, an affordable electrochemical green process is introduced to dope graphene with nitrogen. The process is based on reversing the polarity of two identical graphene oxide (GO) electrodes in molten KCl-LiCl-Li 3 N. During the cathodic step, the oxygen functional groups on the GO surface are removed through direct electro-deoxidation reactions or a reaction with the deposited lithium. In the anodic step, nitrogen is adsorbed onto the surface of graphene and subsequently reacts to form nitrogen-doped graphene. The doping process is controllable, and graphene with up to 7.4 at% nitrogen can be produced. The electrochemically treated electrodes show a specific capacitance of 320 F g -1 in an aqueous KOH electrolyte and maintain 96% of this value after 10 000 cycles. The electrodes also display excellent electrosorption performance in capacitive deionisation devices with the salt removal efficiency reaching up to 18.6 mg g -1 .

  1. Nitrous oxide production by lithotrophic ammonia-oxidizing bacteria and implications for engineered nitrogen-removal systems.

    PubMed

    Chandran, Kartik; Stein, Lisa Y; Klotz, Martin G; van Loosdrecht, Mark C M

    2011-12-01

    Chemolithoautotrophic AOB (ammonia-oxidizing bacteria) form a crucial component in microbial nitrogen cycling in both natural and engineered systems. Under specific conditions, including transitions from anoxic to oxic conditions and/or excessive ammonia loading, and the presence of high nitrite (NO₂⁻) concentrations, these bacteria are also documented to produce nitric oxide (NO) and nitrous oxide (N₂O) gases. Essentially, ammonia oxidation in the presence of non-limiting substrate concentrations (ammonia and O₂) is associated with N₂O production. An exceptional scenario that leads to such conditions is the periodical switch between anoxic and oxic conditions, which is rather common in engineered nitrogen-removal systems. In particular, the recovery from, rather than imposition of, anoxic conditions has been demonstrated to result in N₂O production. However, applied engineering perspectives, so far, have largely ignored the contribution of nitrification to N₂O emissions in greenhouse gas inventories from wastewater-treatment plants. Recent field-scale measurements have revealed that nitrification-related N₂O emissions are generally far higher than emissions assigned to heterotrophic denitrification. In the present paper, the metabolic pathways, which could potentially contribute to NO and N₂O production by AOB have been conceptually reconstructed under conditions especially relevant to engineered nitrogen-removal systems. Taken together, the reconstructed pathways, field- and laboratory-scale results suggest that engineering designs that achieve low effluent aqueous nitrogen concentrations also minimize gaseous nitrogen emissions.

  2. Environmental and economic evaluation of selective non-catalytic reduction of nitrogen oxides

    NASA Astrophysics Data System (ADS)

    Parchevskii, V. M.; Shchederkina, T. E.; Proshina, A. O.

    2017-11-01

    There are two groups of atmosphere protecting measures: technology (primary) and treatment (secondary). When burning high-calorie low-volatile brands of coals in the furnaces with liquid slag removal to achieve emission standards required joint use of these two methods, for example, staged combustion and selective non-catalytic reduction recovery (SNCR). For the economically intelligent combination of these two methods it is necessary to have information not only about the environmental performance of each method, but also the operating costs per unit of reduced emission. The authors of this report are made an environmental-economic analysis of SNCR on boiler Π-50P Kashirskaya power station. The obtained results about the dependence of costs from the load of the boiler and the mass emissions of nitrogen oxides then approximates into empirical formulas, is named as environmental and economic characteristics, which is suitable for downloading into controllers and other control devices for subsequent implementation of optimal control of emissions to ensure compliance with environmental regulations at the lowest cost at any load of the boiler.

  3. Liquid Phase Plasma Synthesis of Iron Oxide Nanoparticles on Nitrogen-Doped Activated Carbon Resulting in Nanocomposite for Supercapacitor Applications.

    PubMed

    Lee, Heon; Lee, Won-June; Park, Young-Kwon; Ki, Seo Jin; Kim, Byung-Joo; Jung, Sang-Chul

    2018-03-25

    Iron oxide nanoparticles supported on nitrogen-doped activated carbon powder were synthesized using an innovative plasma-in-liquid method, called the liquid phase plasma (LPP) method. Nitrogen-doped carbon (NC) was prepared by a primary LPP reaction using an ammonium chloride reactant solution, and an iron oxide/NC composite (IONCC) was prepared by a secondary LPP reaction using an iron chloride reactant solution. The nitrogen component at 3.77 at. % formed uniformly over the activated carbon (AC) surface after a 1 h LPP reaction. Iron oxide nanoparticles, 40~100 nm in size, were impregnated homogeneously over the NC surface after the LPP reaction, and were identified as Fe₃O₄ by X-ray photoelectron spectroscopy and X-ray diffraction. NC and IONCCs exhibited pseudo-capacitive characteristics, and their specific capacitance and cycling stability were superior to those of bare AC. The nitrogen content on the NC surface increased the compatibility and charge transfer rate, and the composites containing iron oxide exhibited a lower equivalent series resistance.

  4. Relationship between peroxyacetyl nitrate and nitrogen oxides in the clean troposphere

    NASA Technical Reports Server (NTRS)

    Singh, H. B.; Salas, L. J.; Ridley, B. A.; Shetter, J. D.; Donahue, N. M.

    1985-01-01

    The first study is presented in which the mixing ratios of peroxyactyl nitrate (PAN) and nitrogen oxides, as well as those of peroxypropionyl nitrate and O3 and relevant meteorological parameters, were measured concurrently at a location that receives clean, continental air. The results show that, in clean conditions, nitrogen oxides present in the form of PAN can be as much or more abundant than the inorganic form. In addition, PAN can be an important source of peroxyacetyl radicals which may be important to oxidation processes in the gas as well as liquid phases.

  5. Wet Oxidation as a Waste Treatment Method in Closed Systems

    NASA Technical Reports Server (NTRS)

    Onisko, B. L.; Wydeven, T.

    1982-01-01

    The chemistry of the wet oxidation process was investigated in relation to production of plant nutrients from plant and human waste materials as required for a closed life support system. Hydroponically grown lettuce plants were used as a model plant waste, and oxygen gas was used as an oxidant. Organic nitrogen content was decreased 88-100%, depending on feed material. Production of ammonia and nitrogen gas accounted for all of the observed decrease in organic nitrogen content. No nitrous oxide (N2O) was detected. The implications of these results for closed life support systems are discussed.

  6. Wet oxidation as a waste treatment in closed systems

    NASA Technical Reports Server (NTRS)

    Onisko, B. L.; Wydeven, T.

    1981-01-01

    The chemistry of the wet oxidation process has been investigated in relation to production of plant nutrients from plant and human waste materials as required for a closed life-support system. Hydroponically grown lettuce plants were used as a model plant waste and oxygen gas was used as oxidant. Organic nitrogen content was decreased 88-100% depending on feed material. Production of ammonia and nitrogen gas account for all of the observed decrease in organic nitrogen content. No nitrous oxide (N2O) was detected. The implications of these results for closed life-support systems are discussed.

  7. Niche differentiation in nitrogen metabolism among methanotrophs within an operational taxonomic unit

    PubMed Central

    2014-01-01

    Background The currently accepted thesis on nitrogenous fertilizer additions on methane oxidation activity assumes niche partitioning among methanotrophic species, with activity responses to changes in nitrogen content being dependent on the in situ methanotrophic community structure Unfortunately, widely applied tools for microbial community assessment only have a limited phylogenetic resolution mostly restricted to genus level diversity, and not to species level as often mistakenly assumed. As a consequence, intragenus or intraspecies metabolic versatility in nitrogen metabolism was never evaluated nor considered among methanotrophic bacteria as a source of differential responses of methane oxidation to nitrogen amendments. Results We demonstrated that fourteen genotypically different Methylomonas strains, thus distinct below the level at which most techniques assign operational taxonomic units (OTU), show a versatile physiology in their nitrogen metabolism. Differential responses, even among strains with identical 16S rRNA or pmoA gene sequences, were observed for production of nitrite and nitrous oxide from nitrate or ammonium, nitrogen fixation and tolerance to high levels of ammonium, nitrate, and hydroxylamine. Overall, reduction of nitrate to nitrite, nitrogen fixation, higher tolerance to ammonium than nitrate and tolerance and assimilation of nitrite were general features. Conclusions Differential responses among closely related methanotrophic strains to overcome inhibition and toxicity from high nitrogen loads and assimilation of various nitrogen sources yield competitive fitness advantages to individual methane-oxidizing bacteria. Our observations proved that community structure at the deepest phylogenetic resolution potentially influences in situ functioning. PMID:24708438

  8. Niche differentiation in nitrogen metabolism among methanotrophs within an operational taxonomic unit.

    PubMed

    Hoefman, Sven; van der Ha, David; Boon, Nico; Vandamme, Peter; De Vos, Paul; Heylen, Kim

    2014-04-04

    The currently accepted thesis on nitrogenous fertilizer additions on methane oxidation activity assumes niche partitioning among methanotrophic species, with activity responses to changes in nitrogen content being dependent on the in situ methanotrophic community structure Unfortunately, widely applied tools for microbial community assessment only have a limited phylogenetic resolution mostly restricted to genus level diversity, and not to species level as often mistakenly assumed. As a consequence, intragenus or intraspecies metabolic versatility in nitrogen metabolism was never evaluated nor considered among methanotrophic bacteria as a source of differential responses of methane oxidation to nitrogen amendments. We demonstrated that fourteen genotypically different Methylomonas strains, thus distinct below the level at which most techniques assign operational taxonomic units (OTU), show a versatile physiology in their nitrogen metabolism. Differential responses, even among strains with identical 16S rRNA or pmoA gene sequences, were observed for production of nitrite and nitrous oxide from nitrate or ammonium, nitrogen fixation and tolerance to high levels of ammonium, nitrate, and hydroxylamine. Overall, reduction of nitrate to nitrite, nitrogen fixation, higher tolerance to ammonium than nitrate and tolerance and assimilation of nitrite were general features. Differential responses among closely related methanotrophic strains to overcome inhibition and toxicity from high nitrogen loads and assimilation of various nitrogen sources yield competitive fitness advantages to individual methane-oxidizing bacteria. Our observations proved that community structure at the deepest phylogenetic resolution potentially influences in situ functioning.

  9. Ambient Ammonium Contribution to total Nitrogen Deposition ...

    EPA Pesticide Factsheets

    There has been a wealth of evidence over the last decade illustrating the rising importance of reduced inorganic nitrogen (NHx = ammonia gas, NH3, plus particulate ammonium, p-NH4) in the overall atmospheric mass balance and deposition of nitrogen as emissions of oxidized nitrogen have decreased throughout a period of stable or increasing NH3 emissions. In addition, the fraction of ambient ammonia relative to p-NH4 generally has risen as a result of decreases in both oxides of nitrogen and sulfur emissions. EPA plans to consider ecological effects related to deposition of nitrogen, of which NHx is a contributing component, in the review of secondary National Ambient Air Quality Standards (NAAQS) for oxides of nitrogen and sulfur (NOx/SOx standard). Although these ecological effects are associated with total nitrogen deposition, it will be important to understand the emissions sources contributing to the total nitrogen deposition and to understand how much of the total nitrogen deposition is from deposition of NHx versus other nitrogen species. Because p-NH4 contributes to nitrogen deposition and can also be a significant component of particulate matter, there is a potential overlap in addressing nitrogen based deposition effects in the secondary PM and NOx/SOx NAAQS. Consequently, there is a policy interest in quantifying the contribution of p-NH4 to total nitrogen deposition. While dry deposition of p-NH4 is calculated through a variety of modeling app

  10. Exterior view of north wall of LongTerm Oxidizer Silo (T28B) ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Exterior view of north wall of Long-Term Oxidizer Silo (T-28B) and Oxidizer Conditioning Structure (T-28D) behind and to its immediate left, looking south. A nitrogen line, used to prepare the Titan II's nitrogen-tetroxide oxidizer, is in the right foreground - Air Force Plant PJKS, Systems Integration Laboratory, Long-Term Oxidizer Silo, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

  11. Impacts of Human Alteration of the Nitrogen Cycle in the U.S. on Radiative Forcing

    EPA Science Inventory

    Nitrogen cycling processes affect radiative forcing directly through emissions of nitrous oxide (N2O) and indirectly because emissions of nitrogen oxide (NO x ) and ammonia (NH3) affect atmospheric concentrations of methane (CH4), carbon dioxide (CO2), water vapor (H2O), ozone (O...

  12. NO news is no new news

    USGS Publications Warehouse

    Fotheringham, C.J.; Keeley, J.E.

    2005-01-01

    In the paper 'NO News', Preston et al. (2004) make a number of erroneous assumptions regarding nitrogen oxide chemistry. These authors also present some very significant misinterpretations of previous research into the effects of various nitrogen oxides on germination of post-fire followers. Methodological differences between the study by Preston et al. (2004) and previous work are also problematic, such as using NO-donors in solution versus the use of direct application of various nitrogen oxides in the gaseous phase. A closer review of these studies, with the proper understanding of nitrogen oxide chemistry, and interpretations of the available literature, would lead to the conclusion that, contrary to the authors' assertions, the Preston et al. (2004) study supports, rather than refutes, earlier findings by Keeley and Fotheringham (1997, 1998a, b, 2000). ?? CAB International 2005.

  13. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Henson, L.C.

    To examine the mechanism of nitrogen sparing in obese subjects on very low calorie diets (VLC-PS), effects of total fasting (TF) and VLC-PS (380 Kcal/day) supplying protein without carbohydrate on metabolites, hormones, urea nitrogen excretion, and plasma (3-/sup 3/H)glucose turnover, (U-/sup 14/C)lysine flux, and (1-/sup 14/C)leucine flux and oxidation were compared. Subjects with a wide range of relative obesity were studied during a control period and after one week of TF. Urea excretion and lysine flux decreased in all subjects, while 3-methylhistidine excretion was unchanged. Glucagon:insulin ratio and cortisol increased, while triiodothyronine (T/sub 3/) decreased and would be expected tomore » be nitrogen-sparing. In a separate study, groups of obese women were studied during a control period and during 14 days of TF or VLC-PS supplying either 80 g (80G) or 40 g (40G) high-quality protein. Increases in branched chain amino acids, ..beta..-hydroxybutyrate, and glucagon:insulin ratio and decrease in T/sub 3/ did not differ among groups. Glucose production decreased to the same extent in all groups. Serum and urinary urea nitrogen were maintained at control values throughout the diet in 80G but decreased to the same extent in TF and 40G. Nitrogen balance estimated from urea nitrogen appearance was negative in all groups.« less

  14. Reduction Expansion Synthesis as Strategy to Control Nitrogen Doping Level and Surface Area in Graphene

    PubMed Central

    Canty, Russell; Gonzalez, Edwin; MacDonald, Caleb; Osswald, Sebastian; Zea, Hugo; Luhrs, Claudia C.

    2015-01-01

    Graphene sheets doped with nitrogen were produced by the reduction-expansion (RES) method utilizing graphite oxide (GO) and urea as precursor materials. The simultaneous graphene generation and nitrogen insertion reactions are based on the fact that urea decomposes upon heating to release reducing gases. The volatile byproducts perform two primary functions: (i) promoting the reduction of the GO and (ii) providing the nitrogen to be inserted in situ as the graphene structure is created. Samples with diverse urea/GO mass ratios were treated at 800 °C in inert atmosphere to generate graphene with diverse microstructural characteristics and levels of nitrogen doping. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to study the microstructural features of the products. The effects of doping on the samples structure and surface area were studied by X-ray diffraction (XRD), Raman Spectroscopy, and Brunauer Emmet Teller (BET). The GO and urea decomposition-reduction process as well as nitrogen-doped graphene stability were studied by thermogravimetric analysis (TGA) coupled with mass spectroscopy (MS) analysis of the evolved gases. Results show that the proposed method offers a high level of control over the amount of nitrogen inserted in the graphene and may be used alternatively to control its surface area. To demonstrate the practical relevance of these findings, as-produced samples were used as electrodes in supercapacitor and battery devices and compared with conventional, thermally exfoliated graphene. PMID:28793618

  15. NOx control techniques for the CPI

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lambert, D.; McGowan, T.F.

    1996-06-01

    After years of air pollution control innovation, the control of emissions of nitrogen oxide compounds stands out as an area where much work remains to be performed in the chemical process industries (CPI). Federal regulations, ozone non-attainment areas, acid rain provisions of the US Clean Air Act, and corporate goals for emission reductions are all motivators. Primary CPI sources are high-temperature combustion systems, including fired heaters, boilers and Kilns. Nitrogen-based processes such as nitric acid manufacture also contribute. The paper discusses the regulations which define the problem and some solutions. These include fuel switching, low-excess air burners, fluegas recirculation, stagedmore » combustion, out of service burners, and wet scrubbing of flue gas. The paper briefly discusses costs of these options.« less

  16. Effect of fuel vapor concentrations on combustor emissions and performance

    NASA Technical Reports Server (NTRS)

    Norgren, C. T.; Ingebo, R. D.

    1973-01-01

    Effects of fuel vaporization on the exhaust emission levels of oxides of nitrogen, carbon monoxide, total hydrocarbons, and smoke number were obtained in an experimental turbojet combustor segment. Two different fuel injectors were used in which liquid ASTM A-1 jet fuel and vapor propane fuel were independently controlled to simulate varying degrees of vaporization. Tests were conducted over a range of inlet-air temperatures from 478 to 700 K, pressures from 4 to 20 atm, and combustor reference velocities from 15.3 to 27.4 m/sec. Converting from liquid to complete vapor fuel resulted in oxides of nitrogen reductions of as much as 22 percent and smoke number reductions up to 51 percent. Supplement data are also presented on flame emissivity, flame temperature, and primary-zone liner wall temperatures.

  17. Methodology for Determination of Grade Crossing Resource-Allocation Guidelines

    DOT National Transportation Integrated Search

    1975-04-01

    The primary objective of this study was to determine the most effective method of reducing emissions of oxides of nitrogen from a two-cylinder version of an EMD series 567C locomotive engine. The NOx control techniques selected for use in this study ...

  18. Universal trace pollutant detector for aircraft monitoring of the ozone layer and industrial areas

    NASA Technical Reports Server (NTRS)

    Filiouguine, I. V.; Kostiouchenko, S. V.; Koudriavtsev, N. N.

    1994-01-01

    A method of monitoring the trace impurities of nitrogen oxides based on controlling of luminescence of NO molecules excited by nanosecond gas discharge have been developed having pptv-ppbv sensitivity and temporal resolution less than 0.01 s.

  19. Final Rule for Control of Air Pollution from Aircraft and Aircraft Engines: Emission Standards and Test Procedures

    EPA Pesticide Factsheets

    EPA is amending the existing emission standards for oxides of nitrogen (NOx) for new commercial aircraft engines. These standards are equivalent to the NOx emission standards of the United Nations International Civil Aviation Organization (ICAO).

  20. Pulsation-based method for reduction of nitrogen oxides content in torch combustion products

    NASA Astrophysics Data System (ADS)

    Berg, I. A.; Porshnev, S. V.; Oshchepkova, V. Y.; Kit, M.

    2018-01-01

    Out of all ways to fuel bum the torch combustion systems is used most often. Even though the processes in the steam boiler are stochastic, the system can be controlled rather easily by changing the flowrate of the air pumped into it and - in case of balanced flue units - exhausters load. Advantages offered by torch-based combustion systems are offset by a disadvantage resulted in oxidation of nitrogen contained in the air. This paper provides rationale for an NOx content reduction method that employs pulsation mode of fuel combustion; it also describes combustion control and monitoring system employed for implementation of this method. Described methodology can be used not only for pulsation combustion studies but also for studies of torches formed by conventional burning systems. The outcome of the experimental study supports the assumption that it is possible to create conditions for NOx content reduction in flue gases by means of cycling the fuel supply on/off valve at the rate of 6 Hz.

  1. Current-biased potentiometric NOx sensor for vehicle emissions

    DOEpatents

    Martin, Louis Peter [Castro Valley, CA; Pham, Ai Quoc [San Jose, CA

    2006-12-26

    A nitrogen oxide sensor system for measuring the amount of nitrogen oxide in a gas. A first electrode is exposed to the gas. An electrolyte is positioned in contact with the first electrode. A second electrode is positioned in contact with the electrolyte. A means for applying a fixed current between the first electrode and the second electrode and monitoring the voltage required to maintain the fixed current provides a measurement of the amount of nitrogen oxide in the gas.

  2. Method for removal of nitrogen oxides from stationary combustion sources

    NASA Technical Reports Server (NTRS)

    Cooper, Charles D. (Inventor); Collins, Michelle M. (Inventor); Clausen, III, Christian A. (Inventor)

    2004-01-01

    A method for removing NO.sub.X from gas streams emanating from stationary combustion sources and manufacturing plants utilizes the injection of hydrogen peroxide into the gas stream for rapid gas-phase oxidation of NO to NO.sub.2 and water-soluble nitrogen acids HNO.sub.2 and HNO.sub.3. The nitrogen acids may be removed from the oxidized gas stream by wet scrubbing or by contact with a particulate alkaline material to form a nitrite/nitrate salt.

  3. The applicability of the catalytic wet-oxidation to CELSS

    NASA Technical Reports Server (NTRS)

    Takahashi, Y.; Nitta, K.; Ohya, H.; Oguchi, M.

    1987-01-01

    The wet oxidation catalysis of Au, Pd, Pt, Rh or Ru on a ceramic honeycomb carrier was traced in detail by 16 to 20 repetitive batch tests each. As a result, Pt or Pd on a honeycomb carrier was shown to catalyze complete nitrogen gasification as N2. Though the catalysts which realize both complete nitrogen gasification and complete oxidation could not be found, the Ru+Rh catalyst was found to be most promising. Ru honeycomb catalyzed both nitrification and nitrogen gasification.

  4. Odd nitrogen production by meteoroids

    NASA Technical Reports Server (NTRS)

    Park, C.; Menees, G. P.

    1978-01-01

    The process by which odd nitrogen species (atomic nitrogen and nitric oxide) are formed during atmospheric entry of meteoroids is analyzed theoretically. An ablating meteoroid is assumed to be a point source of mass with a continuum regime evolving in its wake. The amounts of odd nitrogen species, produced by high-temperature reactions of air in the continuum wake, are calculated by numerical integration of chemical rate equations. Flow properties are assumed to be uniform across the wake, and 29 reactions involving five neutral species and five singly ionized species are considered, as well as vibrational and electron temperature nonequilibrium phenomena. The results, when they are summed over the observed mass, velocity, and entry-angle distribution of meteoroids, provide odd-nitrogen-species annual global production rates as functions of altitude. The peak production of nitric oxide is found to occur at an altitude of about 85 km; atomic nitrogen production peaks at about 95 km. The total annual rate for nitric oxide is 40 million kg; for atomic nitrogen it is 170 million kg.

  5. An Overview of Modeling Middle Atmospheric Odd Nitrogen

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.; Kawa, S. Randolph; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Odd nitrogen (N, NO, NO2, NO3, N2O5, HNO3, HO2NO2, ClONO2, and BrONO2) constituents are important components in the control of middle atmospheric ozone. Several processes lead to the production of odd nitrogen (NO(sub y)) in the middle atmosphere (stratosphere and mesosphere) including the oxidation of nitrous oxide (N2O), lightning, downflux from the thermosphere, and energetic charged particles (e.g., galactic cosmic rays, solar proton events, and energetic electron precipitation). The dominant production mechanism of NO(sub y) in the stratosphere is N2O oxidation, although other processes contribute. Mesospheric NO(sub y) is influenced by N2O oxidation, downflux from the thermosphere, and energetic charged particles. NO(sub y) is destroyed in the middle atmosphere primarily via two processes: 1) dissociation of NO to form N and O followed by N + NO yielding N2 + O to reform even nitrogen; and 2) transport to the troposphere where HNO3 can be rapidly scavenged in water droplets and rained out of the atmosphere. There are fairly significant differences among global models that predict NO(sub y). NO(sub y) has a fairly long lifetime in the stratosphere (months to years), thus disparate transport in the models probably contributes to many of these differences. Satellite and aircraft measurement provide modeling tests of the various components of NO(sub y). Although some recent reaction rate measurements have led to improvements in model/measurement agreement, significant differences do remain. This presentation will provide an overview of several proposed sources and sinks of NO(sub y) and their regions of importance. Multi-dimensional modeling results for NO(sub y) and its components with comparisons to observations will also be presented.

  6. Interactions between Thaumarchaea, Nitrospira and methanotrophs modulate autotrophic nitrification in volcanic grassland soil

    PubMed Central

    Daebeler, Anne; Bodelier, Paul LE; Yan, Zheng; Hefting, Mariet M; Jia, Zhongjun; Laanbroek, Hendrikus J

    2014-01-01

    Ammonium/ammonia is the sole energy substrate of ammonia oxidizers, and is also an essential nitrogen source for other microorganisms. Ammonia oxidizers therefore must compete with other soil microorganisms such as methane-oxidizing bacteria (MOB) in terrestrial ecosystems when ammonium concentrations are limiting. Here we report on the interactions between nitrifying communities dominated by ammonia-oxidizing archaea (AOA) and Nitrospira-like nitrite-oxidizing bacteria (NOB), and communities of MOB in controlled microcosm experiments with two levels of ammonium and methane availability. We observed strong stimulatory effects of elevated ammonium concentration on the processes of nitrification and methane oxidation as well as on the abundances of autotrophically growing nitrifiers. However, the key players in nitrification and methane oxidation, identified by stable-isotope labeling using 13CO2 and 13CH4, were the same under both ammonium levels, namely type 1.1a AOA, sublineage I and II Nitrospira-like NOB and Methylomicrobium-/Methylosarcina-like MOB, respectively. Ammonia-oxidizing bacteria were nearly absent, and ammonia oxidation could almost exclusively be attributed to AOA. Interestingly, although AOA functional gene abundance increased 10-fold during incubation, there was very limited evidence of autotrophic growth, suggesting a partly mixotrophic lifestyle. Furthermore, autotrophic growth of AOA and NOB was inhibited by active MOB at both ammonium levels. Our results suggest the existence of a previously overlooked competition for nitrogen between nitrifiers and methane oxidizers in soil, thus linking two of the most important biogeochemical cycles in nature. PMID:24858784

  7. Cellular Metabolic and Autophagic Pathways: Traffic Control by Redox Signaling

    PubMed Central

    Dodson, Matthew; Darley-Usmar, Victor; Zhang, Jianhua

    2013-01-01

    It has been established that the key metabolic pathways of glycolysis and oxidative phosphorylation are intimately related to redox biology through control of cell signaling. Under physiological conditions glucose metabolism is linked to control of the NADH/NAD redox couple, as well as providing the major reductant, NADPH, for thiol-dependent antioxidant defenses. Retrograde signaling from the mitochondrion to the nucleus or cytosol controls cell growth and differentiation. Under pathological conditions mitochondria are targets for reactive oxygen and nitrogen species and are critical in controlling apoptotic cell death. At the interface of these metabolic pathways, the autophagy-lysosomal pathway functions to maintain mitochondrial quality, and generally serves an important cytoprotective function. In this review we will discuss the autophagic response to reactive oxygen and nitrogen species that are generated from perturbations of cellular glucose metabolism and bioenergetic function. PMID:23702245

  8. Cathode degradation and erosion in high pressure arc discharges

    NASA Technical Reports Server (NTRS)

    Hardy, T. L.; Nakanishi, S.

    1984-01-01

    The various processes which control cathode erosion and degradation were identified and evaluated. A direct current arc discharge was established between electrodes in a pressure-controlled gas flow environment. The cathode holder was designed for easy testing of various cathode materials. The anode was a water cooled copper collector electrode. The arc was powered by a dc power supply with current and voltage regulated cross-over control. Nitrogen and argon were used as propellants and the materials used were two percent thoriated tungsten, barium oxide impregnated porous tungsten, pure tungsten and lanthanum hexaboride. The configurations used were cylindrical solid rods, wire bundles supported by hollow molybdenum tubes, cylindrical hollow tubes, and hollow cathodes of the type used in ion thrusters. The results of the mass loss tests in nitrogen indicated that pure tungsten eroded at a rate more than 10 times faster than the rates of the impregnated tungsten materials. It was found that oxygen impurities of less than 0.5 percent in the nitrogen increased the mass loss rate by a factor of 4 over high purity nitrogen. At power levels less than 1 kW, cathode size and current level did not significantly affect the mass loss rate. The hollow cathode was found to be operable in argon and in nitrogen only at pressures below 400 and 200 torr, respectively.

  9. Experimental identification of nitrogen-vacancy complexes in nitrogen implanted silicon

    NASA Astrophysics Data System (ADS)

    Adam, Lahir Shaik; Law, Mark E.; Szpala, Stanislaw; Simpson, P. J.; Lawther, Derek; Dokumaci, Omer; Hegde, Suri

    2001-07-01

    Nitrogen implantation is commonly used in multigate oxide thickness processing for mixed signal complementary metal-oxide-semiconductor and System on a Chip technologies. Current experiments and diffusion models indicate that upon annealing, implanted nitrogen diffuses towards the surface. The mechanism proposed for nitrogen diffusion is the formation of nitrogen-vacancy complexes in silicon, as indicated by ab initio studies by J. S. Nelson, P. A. Schultz, and A. F. Wright [Appl. Phys. Lett. 73, 247 (1998)]. However, to date, there does not exist any experimental evidence of nitrogen-vacancy formation in silicon. This letter provides experimental evidence through positron annihilation spectroscopy that nitrogen-vacancy complexes indeed form in nitrogen implanted silicon, and compares the experimental results to the ab initio studies, providing qualitative support for the same.

  10. Separate Nitrite, Nitric Oxide, and Nitrous Oxide Reducing Fractions from Pseudomonas perfectomarinus

    PubMed Central

    Payne, W. J.; Riley, P. S.; Cox, C. D.

    1971-01-01

    Pseudomonas perfectomarinus was found to grow anaerobically at the expense of nitrate, nitrite, or nitrous oxide but not chlorate or nitric oxide. In several repetitive experiments, anaerobic incubation in culture media containing nitrate revealed that an average of 82% of the cells in aerobically grown populations were converted to the capacity for respiration of nitrate. Although they did not form colonies under these conditions, the bacteria synthesized the denitrifying enzymes within 3 hr in the absence of oxygen or another acceptable inorganic oxidant. This was demonstrated by the ability, after anaerobic incubation, of cells and of extracts to reduce nitrite, nitric oxide, and nitrous oxide to nitrogen. From crude extracts of cells grown on nitrate, nitrite, or nitrous oxide, separate complex fractions were obtained that utilized reduced nicotinamide adenine dinucleotide as the source of electrons for the reduction of (i) nitrite to nitric oxide, (ii) nitric oxide to nitrous oxide, and (iii) nitrous oxide to nitrogen. Gas chromatographic analyses revealed that each of these fractions reduced only one of the nitrogenous oxides. PMID:4324803

  11. Nitrogen oxides at the UTLS: Combining observations from research aircraft and in-service aircraft

    NASA Astrophysics Data System (ADS)

    Ziereis, Helmut; Stratmann, Greta; Schlager, Hans; Gottschaldt, Klaus-Dirk; Rauthe-Schöch, Armin; Zahn, Andreas; Hoor, Peter; van, Peter

    2016-04-01

    Nitrogen oxides have a decisive influence on the chemistry of the upper troposphere and lower stratosphere. They are key constituents of several reaction chains influencing the production of ozone. They also play an essential role in the cycling of hydroxyl radicals and therefore influence the lifetime of methane. Due to their short lifetime and their variety of sources there is still a high uncertainty about the abundance of nitrogen oxides in the UTLS. Dedicated aircraft campaigns aim to study specific atmospheric questions like lightning, long range transport or aircraft emissions. Usually, within a short time period comprehensive measurements are performed within a more or less restricted region. Therefore, especially trace constituents like nitrogen oxides with short lifetime and a variety of different sources are not represented adequately. On the other hand, routine measurements from in-service aircraft allow observations over longer time periods and larger regions. However, it is nearly impossible to influence the scheduling of in-service aircraft and thereby time and space of the observations. Therefore, the combination of dedicated aircraft campaigns and routine observations might supplement each other. For this study we combine nitrogen oxides data sets obtained with the IAGOS-CARIBIC (Civil Aircraft for the Regular Investigation of the Atmosphere Based on an Instrument Container) flying laboratory and with the German research aircraft HALO (High altitude and long range research aircraft). Data have been acquired within the IAGOS-CARIBIC project on a monthly base using a Lufthansa Airbus A340-600 since December 2004. About four flights are performed each month covering predominantly northern mid-latitudes. Additional flights have been conducted to destinations in South America and South Africa. Since 2012 HALO has been operational. Nitrogen oxides measurements have been performed during six missions covering mid latitudes, tropical as well as Polar Regions. With HALO data can also be obtained at altitudes above the flight levels of commercial airliners. First results combining the nitrogen oxides data sets of both platforms are shown, analysing the temporal and regional distribution of nitrogen oxides at the UTLS.

  12. A Continuous Flow System for the Measurement of Ambient Nitrogen Oxides [NO + NO2] Using Rhodamine B Hydrazide as a Chemosensor

    PubMed Central

    Malingappa, Pandurangappa; Yarradoddappa, Venkataramanappa

    2014-01-01

    A new chemosensor has been used to monitor atmospheric nitrogen oxides [NO + NO2] at parts per billion (ppb) level. It is based on the catalytic reaction of nitrogen oxides with rhodamine B hydrazide (RBH) to produce a colored compound through the hydrolysis of the amide bond of the molecule. A simple colorimeter has been used to monitor atmospheric nitrogen dioxide at ppb level. The air samples were purged through a sampling cuvette containing RBH solution using peristaltic pump. The proposed method has been successfully applied to monitor the ambient nitrogen dioxide levels at traffic junction points within the city limits and the results obtained are compared with the standard Griess-Ilosvay method. PMID:25210422

  13. [Preservation of bread and pastry products in a controlled atmosphere].

    PubMed

    Manchon, P

    1978-01-01

    Industrial soft pastries and the various breads are cereals products containing a humidity which is favorable to the development of mouldiness. Different or various methods of conservation has been attempted. One interesting approach to the problem is packaging in controlled atmosphere. It requires adequate machinery and suitable conditioning materials. Jardry-Buquet and Hayssen's machines are rapidly described as well as some of the packing film used for making air-tight bags. Bad results were observed with nitrogen, argon and a mixture of nitrogen-carbon dioxide. The satisfactory results obtained with the nitrous oxide for cakes (especially fruit-cakes) and for the bread with a mixture of ethylene oxide-carbon dioxide are: a good conservation for a period of 4 to 6 months in both cases. Organoleptic qualities of the products are not significantly diminished after eight weeks of preservation. The gases contained on the bags are analysed at different periods and the progressive disappearance of the nitrous oxide as well as the athylene dioxide was measured. The compounds derivated from these gases were researched on different extracts. No derivatives of the nitrous oxide were observed. From the ethylene oxide, the derivatives found in the bread are diethylene glycol and 2-chloroethanol; their concentrations are respectively 100 and 300 ppm in the case of 85 : 15 mixture, but decrease to a mere trace and 45 ppm in the case of 98 : 2 mixture. The measure of humidity, of peroxides and of the staleness of crumb are favourable for a good conservation.

  14. Increasing importance of deposition of reduced nitrogen in the United States

    PubMed Central

    Li, Yi; Schichtel, Bret A.; Walker, John T.; Schwede, Donna B.; Chen, Xi; Lehmann, Christopher M. B.; Puchalski, Melissa A.; Gay, David A.; Collett, Jeffrey L.

    2016-01-01

    Rapid development of agriculture and fossil fuel combustion greatly increased US reactive nitrogen emissions to the atmosphere in the second half of the 20th century, resulting in excess nitrogen deposition to natural ecosystems. Recent efforts to lower nitrogen oxides emissions have substantially decreased nitrate wet deposition. Levels of wet ammonium deposition, by contrast, have increased in many regions. Together these changes have altered the balance between oxidized and reduced nitrogen deposition. Across most of the United States, wet deposition has transitioned from being nitrate-dominated in the 1980s to ammonium-dominated in recent years. Ammonia has historically not been routinely measured because there are no specific regulatory requirements for its measurement. Recent expansion in ammonia observations, however, along with ongoing measurements of nitric acid and fine particle ammonium and nitrate, permit new insight into the balance of oxidized and reduced nitrogen in the total (wet + dry) US nitrogen deposition budget. Observations from 37 sites reveal that reduced nitrogen contributes, on average, ∼65% of the total inorganic nitrogen deposition budget. Dry deposition of ammonia plays an especially key role in nitrogen deposition, contributing from 19% to 65% in different regions. Future progress toward reducing US nitrogen deposition will be increasingly difficult without a reduction in ammonia emissions. PMID:27162336

  15. Nitrogen oxides emissions from the MILD combustion with the conditions of recirculation gas.

    PubMed

    Park, Min; Shim, Sung Hoon; Jeong, Sang Hyun; Oh, Kwang-Joong; Lee, Sang-Sup

    2017-04-01

    The nitrogen oxides (NO x ) reduction technology by combustion modification which has economic benefits as a method of controlling NO x emitted in the combustion process, has recently been receiving a lot of attention. Especially, the moderate or intense low oxygen dilution (MILD) combustion which applied high temperature flue gas recirculation has been confirmed for its effectiveness with regard to solid fuel as well. MILD combustion is affected by the flue gas recirculation ratio and the composition of recirculation gas, so its NO x reduction efficiency is determined by them. In order to investigate the influence of factors which determine the reduction efficiency of NO x in MILD coal combustion, this study changed the flow rate and concentration of nitrogen (N 2 ), carbon dioxide (CO 2 ) and steam (H 2 O) which simulate the recirculation gas during the MILD coal combustion using our lab-scale drop tube furnace and performed the combustion experiment. As a result, its influence by the composition of recirculation gas was insignificant and it was shown that flue gas recirculation ratio influences the change of NO x concentration greatly. We investigated the influence of factors determining the nitrogen oxides (NO x ) reduction efficiency in MILD coal combustion, which applied high-temperature flue gas recirculation. Using a lab-scale drop tube furnace and simulated recirculation gas, we conducted combustion testing changing the recirculation gas conditions. We found that the flue gas recirculation ratio influences the reduction of NO x emissions the most.

  16. Nickel supported on nitrogen-doped carbon nanotubes as hydrogen oxidation reaction catalyst in alkaline electrolyte

    DOE PAGES

    Zhuang, Zhongbin; Giles, Stephen A.; Zheng, Jie; ...

    2016-01-14

    The development of a low-cost, high-performance platinum-group-metal-free hydroxide exchange membrane fuel cell is hindered by the lack of a hydrogen oxidation reaction catalyst at the anode. Here we report that a composite catalyst, nickel nanoparticles supported on nitrogen-doped carbon nanotubes, has hydrogen oxidation activity similar to platinum-group metals in alkaline electrolyte. Although nitrogen-doped carbon nanotubes are a very poor hydrogen oxidation catalyst, as a support, it increases the catalytic performance of nickel nanoparticles by a factor of 33 (mass activity) or 21 (exchange current density) relative to unsupported nickel nanoparticles. Density functional theory calculations indicate that the nitrogen-doped support stabilizesmore » the nanoparticle against reconstruction, while nitrogen located at the edge of the nanoparticle tunes local adsorption sites by affecting the d-orbitals of nickel. Here, owing to its high activity and low cost, our catalyst shows significant potential for use in low-cost, high-performance fuel cells.« less

  17. Nickel supported on nitrogen-doped carbon nanotubes as hydrogen oxidation reaction catalyst in alkaline electrolyte

    PubMed Central

    Zhuang, Zhongbin; Giles, Stephen A.; Zheng, Jie; Jenness, Glen R.; Caratzoulas, Stavros; Vlachos, Dionisios G.; Yan, Yushan

    2016-01-01

    The development of a low-cost, high-performance platinum-group-metal-free hydroxide exchange membrane fuel cell is hindered by the lack of a hydrogen oxidation reaction catalyst at the anode. Here we report that a composite catalyst, nickel nanoparticles supported on nitrogen-doped carbon nanotubes, has hydrogen oxidation activity similar to platinum-group metals in alkaline electrolyte. Although nitrogen-doped carbon nanotubes are a very poor hydrogen oxidation catalyst, as a support, it increases the catalytic performance of nickel nanoparticles by a factor of 33 (mass activity) or 21 (exchange current density) relative to unsupported nickel nanoparticles. Density functional theory calculations indicate that the nitrogen-doped support stabilizes the nanoparticle against reconstruction, while nitrogen located at the edge of the nanoparticle tunes local adsorption sites by affecting the d-orbitals of nickel. Owing to its high activity and low cost, our catalyst shows significant potential for use in low-cost, high-performance fuel cells. PMID:26762466

  18. On the use of thermal NF3 as the fluorination and oxidation agent in treatment of used nuclear fuels

    NASA Astrophysics Data System (ADS)

    Scheele, Randall; McNamara, Bruce; Casella, Andrew M.; Kozelisky, Anne

    2012-05-01

    This paper presents results of our investigation on the use of nitrogen trifluoride as a fluorination or fluorination/oxidation agent for separating valuable constituents from used nuclear fuels by exploiting the different volatilities of the constituent fission product and actinide fluorides. Our thermodynamic calculations show that nitrogen trifluoride has the potential to produce volatile fission product and actinide fluorides from oxides and metals that can form volatile fluorides. Simultaneous thermogravimetric and differential thermal analyses show that the oxides of lanthanum, cerium, rhodium, and plutonium are fluorinated but do not form volatile fluorides when treated with nitrogen trifluoride at temperatures up to 550 °C. However, depending on temperature, volatile fluorides or oxyfluorides can form from nitrogen trifluoride treatment of the oxides of niobium, molybdenum, ruthenium, tellurium, uranium, and neptunium. Thermoanalytical studies demonstrate near-quantitative separation of uranium from plutonium in a mixed 80% uranium and 20% plutonium oxide. Our studies of neat oxides and metals suggest that the reactivity of nitrogen trifluoride may be adjusted by temperature to selectively separate the major volatile fuel constituent uranium from minor volatile constituents, such as Mo, Tc, Ru and from the non-volatile fuel constituents based on differences in their reaction temperatures and kinetic behaviors. This reactivity is novel with respect to that reported for other fluorinating reagents F2, BrF5, ClF3.

  19. Chlorine activation indoors and outdoors via surface-mediated reactions of nitrogen oxides with hydrogen chloride

    PubMed Central

    Raff, Jonathan D.; Njegic, Bosiljka; Chang, Wayne L.; Gordon, Mark S.; Dabdub, Donald; Gerber, R. Benny; Finlayson-Pitts, Barbara J.

    2009-01-01

    Gaseous HCl generated from a variety of sources is ubiquitous in both outdoor and indoor air. Oxides of nitrogen (NOy) are also globally distributed, because NO formed in combustion processes is oxidized to NO2, HNO3, N2O5 and a variety of other nitrogen oxides during transport. Deposition of HCl and NOy onto surfaces is commonly regarded as providing permanent removal mechanisms. However, we show here a new surface-mediated coupling of nitrogen oxide and halogen activation cycles in which uptake of gaseous NO2 or N2O5 on solid substrates generates adsorbed intermediates that react with HCl to generate gaseous nitrosyl chloride (ClNO) and nitryl chloride (ClNO2), respectively. These are potentially harmful gases that photolyze to form highly reactive chlorine atoms. The reactions are shown both experimentally and theoretically to be enhanced by water, a surprising result given the availability of competing hydrolysis reaction pathways. Airshed modeling incorporating HCl generated from sea salt shows that in coastal urban regions, this heterogeneous chemistry increases surface-level ozone, a criteria air pollutant, greenhouse gas and source of atmospheric oxidants. In addition, it may contribute to recently measured high levels of ClNO2 in the polluted coastal marine boundary layer. This work also suggests the potential for chlorine atom chemistry to occur indoors where significant concentrations of oxides of nitrogen and HCl coexist. PMID:19620710

  20. 40 CFR Appendix A to Part 55 - Listing of State and Local Requirements Incorporated by Reference Into Part 55, by State

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Prohibitions (Revised 12/6/76) Rule 405 Nitrogen Oxides Emission Standards, Limitations and Prohibitions... (Adopted 7/12/94) Rule 427 Marine Tanker Loading (Adopted 4/26/95) Rule 429 Oxides of Nitrogen and Carbon... Nitrogen from Industrial, Institutional, Commercial Boilers, Steam Generators, and Process Heaters (Adopted...

  1. 40 CFR 89.3 - Acronyms and abbreviations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... National Technical Information Service NO Nitric oxide NO2 Nitrogen dioxide NOX Oxides of nitrogen O2... Selective Enforcement Auditing SI Spark-ignition THC Total hydrocarbon U.S.C. United States Code VOC...

  2. 40 CFR 89.3 - Acronyms and abbreviations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... National Technical Information Service NO Nitric oxide NO2 Nitrogen dioxide NOX Oxides of nitrogen O2... Selective Enforcement Auditing SI Spark-ignition THC Total hydrocarbon U.S.C. United States Code VOC...

  3. 40 CFR 89.3 - Acronyms and abbreviations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... National Technical Information Service NO Nitric oxide NO2 Nitrogen dioxide NOX Oxides of nitrogen O2... Selective Enforcement Auditing SI Spark-ignition THC Total hydrocarbon U.S.C. United States Code VOC...

  4. Field application of nitrogen and phenylacetylene to mitigate greenhouse gas emissions from landfill cover soils: effects on microbial community structure.

    PubMed

    Im, Jeongdae; Lee, Sung-Woo; Bodrossy, Levente; Barcelona, Michael J; Semrau, Jeremy D

    2011-01-01

    Landfills are large sources of CH(4), but a considerable amount of CH(4) can be removed in situ by methanotrophs if their activity can be stimulated through the addition of nitrogen. Nitrogen can, however, lead to increased N(2)O production. To examine the effects of nitrogen and a selective inhibitor on CH(4) oxidation and N(2)O production in situ, 0.5 M of NH(4)Cl and 0.25 M of KNO(3), with and without 0.01% (w/v) phenylacetylene, were applied to test plots at a landfill in Kalamazoo, MI from 2007 November to 2009 July. Nitrogen amendments stimulated N(2)O production but had no effect on CH(4) oxidation. The addition of phenylacetylene stimulated CH(4) oxidation while reducing N(2)O production. Methanotrophs possessing particulate methane monooxygenase and archaeal ammonia-oxidizers (AOAs) were abundant. The addition of nitrogen reduced methanotrophic diversity, particularly for type I methanotrophs. The simultaneous addition of phenylacetylene increased methanotrophic diversity and the presence of type I methanotrophs. Clone libraries of the archaeal amoA gene showed that the addition of nitrogen increased AOAs affiliated with Crenarchaeal group 1.1b, while they decreased with the simultaneous addition of phenylacetylene. These results suggest that the addition of phenylacetylene with nitrogen reduces N(2)O production by selectively inhibiting AOAs and/or type II methanotrophs.

  5. 78 FR 14591 - Notice of Lodging of Proposed Consent Decree Under the Clean Air Act

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-06

    ... pollution control technologies to reduce emissions of nitrogen oxides, sulfur dioxide, and particulate... comment on the consent decree. Comments should be addressed to the Assistant Attorney General, Environment... Section Chief, Environmental Enforcement Section, Environment and Natural Resources Division. [FR Doc...

  6. Fluidized-bed combustion reduces atmospheric pollutants

    NASA Technical Reports Server (NTRS)

    Jonke, A. A.

    1972-01-01

    Method of reducing sulfur and nitrogen oxides released during combustion of fossil fuels is described. Fuel is burned in fluidized bed of solids with simultaneous feeding of crushed or pulverized limestone to control emission. Process also offers high heat transfer rates and efficient contacting for gas-solid reactions.

  7. Woody Debris: Denitrification Hotspots and N2O Production in Fluvial Systems

    EPA Science Inventory

    The maintenance and restoration of forested riparian cover is important for watershed nitrogen (N) cycling. Forested riparian zones provide woody debris to streams that may stimulate in-stream denitrification and control nitrous oxide (N2O) production. We examined the effects of ...

  8. 40 CFR 52.2771 - Classification of regions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Classification of regions. The U.S. Virgin Islands plan was evaluated on the basis of the following classifications: Air quality control region Pollutant Particulate matter Sulfur oxides Nitrogen dioxide Carbon... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Classification of regions. 52.2771...

  9. 40 CFR 52.2771 - Classification of regions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Classification of regions. The U.S. Virgin Islands plan was evaluated on the basis of the following classifications: Air quality control region Pollutant Particulate matter Sulfur oxides Nitrogen dioxide Carbon... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Classification of regions. 52.2771...

  10. Low-temperature conversion of ammonia to nitrogen in water with ozone over composite metal oxide catalyst.

    PubMed

    Chen, Yunnen; Wu, Ye; Liu, Chen; Guo, Lin; Nie, Jinxia; Chen, Yu; Qiu, Tingsheng

    2018-04-01

    As one of the most important water pollutants, ammonia nitrogen emissions have increased year by year, which has attracted people's attention. Catalytic ozonation technology, which involves production of ·OH radical with strong oxidation ability, is widely used in the treatment of organic-containing wastewater. In this work, MgO-Co 3 O 4 composite metal oxide catalysts prepared with different fabrication conditions have been systematically evaluated and compared in the catalytic ozonation of ammonia (50mg/L) in water. In terms of high catalytic activity in ammonia decomposition and high selectivity for gaseous nitrogen, the catalyst with MgO-Co 3 O 4 molar ratio 8:2, calcined at 500°C for 3hr, was the best one among the catalysts we tested, with an ammonia nitrogen removal rate of 85.2% and gaseous nitrogen selectivity of 44.8%. In addition, the reaction mechanism of ozonation oxidative decomposition of ammonia nitrogen in water with the metal oxide catalysts was discussed. Moreover, the effect of coexisting anions on the degradation of ammonia was studied, finding that SO 4 2- and HCO 3 - could inhibit the catalytic activity while CO 3 2- and Br - could promote it. The presence of coexisting cations had very little effect on the catalytic ozonation of ammonia nitrogen. After five successive reuses, the catalyst remained stable in the catalytic ozonation of ammonia. Copyright © 2017. Published by Elsevier B.V.

  11. Tracking agricultural soil nitric oxide emission variations with novel isotopic measurements

    NASA Astrophysics Data System (ADS)

    Miller, D. J.; Chai, J.; Guo, F.; Overby, S.; Dell, C. J.; Karsten, H.; Hastings, M. G.

    2016-12-01

    Agricultural production systems impact the reactive nitrogen cycle via atmospheric nitrogen emissions including nitric oxide, denoted as total nitrogen oxides (NOx). NOx serve as precursors to ozone and nitrate aerosols, influencing air quality, radiative forcing, and ecosystem health. With recent declines in fuel combustion sources, soil emissions are an increasing contributor to NOx budgets. However, spatially heterogeneous, episodic soil NOx pulses are challenging to constrain and remain highly uncertain. Using a novel hourly resolution soil flux chamber-based NOx collection method, we investigate fertilizer management and climatic controls on cropland soil NOx flux and nitrogen isotopic composition (δ15N-NOx) natural abundance variations with field-based and laboratory measurements. No-till, rain-fed corn plots were sampled daily (triplicate isotope samples per treatment per day) following broadcast and shallow-disk injected dairy manure applications as part of a sustainable dairy cropping study in State College, PA (Penn State University; USDA-ARS). Injected manure plots exhibited median fluxes two times higher with larger spatial variations than that for broadcast manure. Soil emission δ15N-NOx signatures of -45 to -20 ‰ were correlated with flux magnitudes across both treatments. Median δ15N-NOx signatures for injected manure were lower with larger spatial variations (-32 ± 9 ‰) than that for broadcast manure (-24 ± 1.5 ‰). These differences are likely linked with higher NH4+ availability for nitrification with injected manure in contrast with higher NH3 volatilization and higher soil δ15N-NH4+ for broadcast manure. Although NOx fluxes were suppressed 1-2 days after heavy rainfall (>35 % water-filled pore space), δ15N-NOx remained consistent. Controlled laboratory incubation studies will also be presented quantifying links with inorganic substrate and fertilizer δ15N. Our observations suggest that agricultural soil δ15N-NOx signatures are linked with fertilizer δ15N and soil NH4+ availability and could serve as an observational tracer of regional fertilizer management gradients. Our results have significant implications for field-scale validations of soil NOx emission inventories and predictions of soil NOx influences on atmospheric oxidation chemistry.

  12. Post-anoxic denitrification via nitrite driven by PHB in feast-famine sequencing batch reactor.

    PubMed

    Chen, Hong-Bo; Yang, Qi; Li, Xiao-Ming; Wang, Yan; Luo, Kun; Zeng, Guang-Ming

    2013-08-01

    Recently, it was found that excess phosphorus removal could be induced by aerobic/extended-idle regime. In this study, an anoxic period was introduced after the aeration to realize simultaneous nitrogen and phosphorus removal. The results demonstrated that stable partial nitrification could be achieved by controlling the aeration duration at 2.5h because it could not only obtain a desirable ammonia oxidation to nitrite but also avoid the extensive aeration converting nitrite to nitrate, and moreover, the accumulated poly-3-hydroxybutyrate still remain in a relative sufficient concentration (1.5mmolCg(-1) VSS), which could subsequently served as internal carbon source for post-anoxic denitrification. The nitrite accumulation ratio was observed to have relatively high correlation with biological nutrient removal. Over stages with stable high-level nitrite accumulation, the process achieved desirable and stable nitrogen and phosphorus removal efficiencies averaging 95% and 99% respectively. Fluorescence in situ hybridization analysis showed that the faster growth rate of the ammonia oxidizing bacteria than the nitrite oxidizing bacteria was the main reason for achieving nitrite accumulation. In addition, the secondary phosphorus release was negligible and the process maintained excellent nutrient removal under low influent ammonia nitrogen. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Evaluating the impacts of triclosan on wastewater treatment performance during startup and acclimation.

    PubMed

    Holzem, R M; Gardner, C M; Gunsch, C K

    2018-01-01

    Triclosan (TCS) is a broad range antimicrobial agent used in many personal care products, which is commonly discharged to wastewater treatment facilities (WWTFs). This study examined the impact of TCS on wastewater treatment performance using laboratory bench-scale sequencing batch reactors (SBRs) coupled with anaerobic digesters. The SBRs were continuously fed synthetic wastewater amended with or without 0.68 μM TCS, with the aim of determining the effect of chronic TCS exposure as opposed to a pulse TCS addition as previously studied. Overall, the present study suggests inhibition of nitrogen removal during reactor startup. However, NH 4 + removal fully rebounded after 63 days, suggesting acclimation of the associated microbial communities to TCS. An initial decrease in microbial community diversity was observed in the SBRs fed TCS as compared to the control SBRs, followed by an increase in community diversity, which coincided with the increase in NH 4 + removal. Elevated levels of NO 3 - and NO 2 - were found in the reactor effluent after day 58, however, suggesting ammonia oxidizing bacteria rebounding more rapidly than nitrogen oxidizing bacteria. Similar effects on treatment efficiencies at actual WWTFs have not been widely observed, suggesting that continuous addition of TCS in their influent may have selected for TCS-resistant nitrogen oxidizing bacteria.

  14. Interference of oxygen, carbon dioxide, and water vapor on the analysis for oxides of nitrogen by chemiluminescence

    NASA Technical Reports Server (NTRS)

    Maahs, H. G.

    1975-01-01

    The interference of small concentrations (less than 4 percent by volume) of oxygen, carbon dioxide, and water vapor on the analysis for oxides of nitrogen by chemiluminescence was measured. The sample gas consisted primarily of nitrogen, with less than 100 parts per million concentration of nitric oxide, and with small concentrations of oxygen, carbon dioxide, and water vapor added. Results obtained under these conditions indicate that although oxygen does not measurably affect the analysis for nitric oxide, the presence of carbon dioxide and water vapor causes the indicated nitric oxide concentration to be too low. An interference factor - defined as the percentage change in indicated nitric oxide concentration (relative to the true nitric oxide concentration) divided by the percent interfering gas present - was determined for carbon dioxide to be -0.60 + or - 0.04 and for water vapor to be -2.1 + or - 0.3.

  15. Treatment of Ammonia Nitrogen Wastewater in Low Concentration by Two-Stage Ozonization.

    PubMed

    Luo, Xianping; Yan, Qun; Wang, Chunying; Luo, Caigui; Zhou, Nana; Jian, Chensheng

    2015-09-23

    Ammonia nitrogen wastewater (about 100 mg/L) was treated by two-stage ozone oxidation method. The effects of ozone flow rate and initial pH on ammonia removal were studied, and the mechanism of ammonia nitrogen removal by ozone oxidation was discussed. After the primary stage of ozone oxidation, the ammonia removal efficiency reached 59.32% and pH decreased to 6.63 under conditions of 1 L/min ozone flow rate and initial pH 11. Then, the removal efficiency could be over 85% (the left ammonia concentration was lower than 15 mg/L) after the second stage, which means the wastewater could have met the national discharge standards of China. Besides, the mechanism of ammonia removal by ozone oxidation was proposed by detecting the products of the oxidation: ozone oxidation directly and ·OH oxidation; ammonia was mainly transformed into NO₃(-)-N, less into NO₂(-)-N, not into N₂.

  16. Zinc oxide nanoparticles affect carbon and nitrogen mineralization of Phoenix dactylifera leaf litter in a sandy soil.

    PubMed

    Rashid, Muhammad Imtiaz; Shahzad, Tanvir; Shahid, Muhammad; Ismail, Iqbal M I; Shah, Ghulam Mustafa; Almeelbi, Talal

    2017-02-15

    We investigated the impact of zinc oxide nanoparticles (ZnO NPs; 1000mgkg -1 soil) on soil microbes and their associated soil functions such as date palm (Phoenix dactylifera) leaf litter (5gkg -1 soil) carbon and nitrogen mineralization in mesocosms containing sandy soil. Nanoparticles application in litter-amended soil significantly decreased the cultivable heterotrophic bacterial and fungal colony forming units (cfu) compared to only litter-amended soil. The decrease in cfu could be related to lower microbial biomass carbon in nanoparticles-litter amended soil. Likewise, ZnO NPs also reduced CO 2 emission by 10% in aforementioned treatment but this was higher than control (soil only). Labile Zn was only detected in the microbial biomass of nanoparticles-litter applied soil indicating that microorganisms consumed this element from freely available nutrients in the soil. In this treatment, dissolved organic carbon and mineral nitrogen were 25 and 34% lower respectively compared to litter-amended soil. Such toxic effects of nanoparticles on litter decomposition resulted in 130 and 122% lower carbon and nitrogen mineralization efficiency respectively. Hence, our results entail that ZnO NPs are toxic to soil microbes and affect their function i.e., carbon and nitrogen mineralization of applied litter thus confirming their toxicity to microbial associated soil functions. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. “Transference Ratios” to Predict Total Oxidized Sulfur and Nitrogen Deposition – Part II, Modeling Results

    EPA Science Inventory

    The current study examines predictions of transference ratios and related modeled parameters for oxidized sulfur and oxidized nitrogen using five years (2002-2006) of 12-km grid cell-specific annual estimates from EPA’s Community Air Quality Model (CMAQ) for five selected sub-re...

  18. 40 CFR 60.49b - Reporting and recordkeeping requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... into the oxidation zone. (2) Standard for nitrogen oxides. (i) When fossil fuel alone is combusted, the NOX emission limit for fossil fuel in § 60.44b(a) applies. (ii) When natural gas and chemical by... back into the combustion air. (2) Standard for nitrogen oxides. (i) When fossil fuel alone is combusted...

  19. 40 CFR 60.49b - Reporting and recordkeeping requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... into the oxidation zone. (2) Standard for nitrogen oxides. (i) When fossil fuel alone is combusted, the NOX emission limit for fossil fuel in § 60.44b(a) applies. (ii) When natural gas and chemical by... back into the combustion air. (2) Standard for nitrogen oxides. (i) When fossil fuel alone is combusted...

  20. 40 CFR 60.49b - Reporting and recordkeeping requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... into the oxidation zone. (2) Standard for nitrogen oxides. (i) When fossil fuel alone is combusted, the NOX emission limit for fossil fuel in § 60.44b(a) applies. (ii) When natural gas and chemical by... back into the combustion air. (2) Standard for nitrogen oxides. (i) When fossil fuel alone is combusted...

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