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Sample records for ammonia fluxes obtained

  1. Fluxes of ammonia in the coastal marine boundary layer

    DEFF Research Database (Denmark)

    Sørensen, L.L.; Hertel, O.; Skjøth, C.A.

    2003-01-01

    Concentrations of ammonia in air and ammonium in surface water were measured from a platform in the Southern North Sea close to the Dutch coast. Fluxes were derived from the measurements applying Monin-Obukhov similarity theory and exchange velocities calculated. The fluxes and air concentrations...... and that the calculated overall ammonia dry deposition may be overestimated by a factor two or more in the coastal region. A more detailed study is needed in order to quantify how this may influence overall deposition to given marine waters. In some cases the deposition may solely be redistributed whereas the total...... deposition is only marginally influenced. (C) 2003 Elsevier Science Ltd. All rights reserved....

  2. The obtaining of iron acetate from processed iron comprising catalyst of ammonia synthesis

    International Nuclear Information System (INIS)

    Mansurov, M.M.; Lugovenko, A.N.; Mirzoeva, M.M.

    1993-01-01

    Present article is devoted to obtaining of iron acetate from processed iron comprising catalyst of ammonia synthesis. The method of synthesis of iron acetate from processed iron comprising catalyst of ammonia synthesis was elaborated. The structure of complex was determined.

  3. Vertical distribution and fluxes of ammonia at Great Dun Fell

    Science.gov (United States)

    Sutton, M. A.; Perthue, E.; Fowler, D.; Storeton-West, R. L.; Cape, J. N.; Arends, B. G.; Möls, J. J.

    As part of the study of the ammonia budget over Great Dun Fell, measurements of fluxes of gaseous ammonia (NH 3) with the hill surface (grass moorland and blanket bog) were made using micrometeorological techniques, to provide information on NH 3 removal by the hill surface and on vertical concentration gradients. Measurements of vertical concentration, χ, profiles of NH 3 concentration were coupled with turbulent diffusivities to determine fluxes, Fg deposition velocities, and canopy resistances, Rc to uptake by the ground. Consistent with published measurements for this site, NH 3 was generally found to deposit efficiently to the vegetation canopy, with mean Rc of 5 and 27 s m - for example days shown. However, short periods of NH 3 emission from the moorland were also observed at small χ (cloud processing: depletion of χ by in-cloud reaction would be expected to favour NH 3 emission from down-wind agricultural land and moorland, though emission from the hill itself during immersion in cloud is unlikely. Comparison of two measurement techniques to determine air concentrations (batch wet rotating denuder, inlet 0.5 m height; continuous wet denuder, inlets 0.3, 2 m heights) showed acceptable agreement, although because vertical concentration gradients were large (small Rc) the height of sampling had a substantial effect. Vertical gradients are also relevant to the use of the measured concentrations as estimates of NH 3 in the air mass passing over the hill, for modelling atmospheric budgets. Where NH 3 deposition occurs at the maximum rate, concentrations measured at 1 m require a 35% correction in neutral conditions when scaling to a reference height of 10 m.

  4. Obtaining evapotranspiration and surface energy fluxes with ...

    African Journals Online (AJOL)

    In this study, SEBAL (Surface Energy Balance Algorithm for Land), a remote sensing based evapotranspiration model, has been applied with Landsat ETM+ sensor for the estimation of actual ... The land uses in this study area consists of irrigated agriculture, rain-fed agriculture and livestock grazing. The obtained results ...

  5. MEASUREMENT OF BI-DIRECTIONAL AMMONIA FLUXES OVER SOYBEAN USING MODIFIED BOWEN-RATIO TECHNIQUE

    Science.gov (United States)

    Measurements of bi-directional ammonia exchange over a fertilized soybean canopy are presented for an 8-week period during the summer of 2002. The modified Bowne-ratio approach was used to determine fluxes from vertical NH3 and temperature gradients in combination with eddy covar...

  6. Background concentrations and fluxes of atmospheric ammonia overa deciduous forest

    DEFF Research Database (Denmark)

    Hansen, Kristina; Pryor, Sara C.; Bøgh, Eva

    2015-01-01

    to quantify the phase-partitioning and diagnose possible causes of upward NH3 fluxes. Data from 2013 combined with previous NH3 studies at this site indicate a seasonal background NH3 concentration of spring: 0.92 ± 0.95, summer: 0.30 ± 0.39, autumn: 0.20 ± 0.26, and winter: 0.26 ± 0.1 μg NH3-N m−3. Air mass...... back trajectories from the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model did not indicate any directional bias in the measured NH3 concentration confirming the absence of strong local sources of NH3. The NH3 fluxes were mainly upward (emission) and had a magnitude of up to 0...

  7. Aqua ammonia 15 N obtaining and application with vainness for sugar-cane fertilization

    International Nuclear Information System (INIS)

    Vitti, Andre Cesar; Trivellin, Paulo Cesar O.; Oliveira, Claudineia R. de; Bendassoli, Jose A.

    2000-01-01

    Nitrogen compounds marked with the isotope 15 N are continuously being used in agronomic studies and, when associated to the isotopic dilution technique, they constitute an important tool in clarifying the N cycle. At the Centro de Energia Nuclear na Agricultura (CENA/USP), it was obtained ( 15 NH 4 ) 2 SO 4 enhanced at 3,5% of 15 N atoms, by means of the ionic exchange chromatography technique, which made possible to produce aqua ammonia ( 15 NH 3 aq). Four repetitions were taken to the aqua ammonia production process to use the nitrogen compound in the field experiment. In each process 150g of ammonium sulfate enhanced at 3,5% of 15 N atoms was used, obtaining 31,0 ± 1,6 g of aqua ammonia on the average (80% yield), with the same enhancement. The incidence of isotopic dilution has not been observed during the procedure, what made the use of such methodology possible. After obtaining the aqua ammonia 15 N through this procedure, it was added to the vinasse (an equivalent to 50 m 3 ha -1 ) in doses that corresponded to 70 kg ha -1 of N-NH 3 aq. The mixture was applied to the sugar-cane straw on the soil's surface, aimed to the crop's fertilization. The compound's isotopic composition was analyzed by means of a spectrometer of masses ANCA-SL Europe Scientific, while the total-N volatilized, by the micro-Kjeldahl. Method. In accordance to the low NH 3 (6,4 ± 1,9 kg ha -1 ) volatilization results, it could be concluded that the application of vinasse and aqua ammonia mixture to the straw on the soil's surface was efficient, due to the vinasse's acid character, which allowed the NH 3 , in presence of the ion H + , to stay in the NH 4 + form in solution. (author)

  8. Flux balance analysis of ammonia assimilation network in E. coli predicts preferred regulation point.

    Directory of Open Access Journals (Sweden)

    Lu Wang

    Full Text Available Nitrogen assimilation is a critical biological process for the synthesis of biomolecules in Escherichia coli. The central ammonium assimilation network in E. coli converts carbon skeleton α-ketoglutarate and ammonium into glutamate and glutamine, which further serve as nitrogen donors for nitrogen metabolism in the cell. This reaction network involves three enzymes: glutamate dehydrogenase (GDH, glutamine synthetase (GS and glutamate synthase (GOGAT. In minimal media, E. coli tries to maintain an optimal growth rate by regulating the activity of the enzymes to match the availability of the external ammonia. The molecular mechanism and the strategy of the regulation in this network have been the research topics for many investigators. In this paper, we develop a flux balance model for the nitrogen metabolism, taking into account of the cellular composition and biosynthetic requirements for nitrogen. The model agrees well with known experimental results. Specifically, it reproduces all the (15N isotope labeling experiments in the wild type and the two mutant (ΔGDH and ΔGOGAT strains of E. coli. Furthermore, the predicted catalytic activities of GDH, GS and GOGAT in different ammonium concentrations and growth rates for the wild type, ΔGDH and ΔGOGAT strains agree well with the enzyme concentrations obtained from western blots. Based on this flux balance model, we show that GS is the preferred regulation point among the three enzymes in the nitrogen assimilation network. Our analysis reveals the pattern of regulation in this central and highly regulated network, thus providing insights into the regulation strategy adopted by the bacteria. Our model and methods may also be useful in future investigations in this and other networks.

  9. What can we learn about ammonia fluxes from open-path eddy covariance measurements?

    Science.gov (United States)

    Pan, D.; Zondlo, M. A.; Benedict, K. B.; Schichtel, B. A.; Ham, J. M.; Shonkwiler, K. B.; Collett, J. L., Jr.

    2016-12-01

    Ammonia (NH3) is an important component of bio-atmospheric N cycle with implications of regional air quality, human and ecosystem health degradation, and global climate change. NH3 fluxes have high spatiotemporal variability controlled by several factors, such as atmospheric NH3 concentration, meteorological conditions, and compensation point of underlying surfaces. Quantifying NH3 fluxes is further complicated by severe measurement challenges including adsorption to instrument surfaces, low mole fractions, and gas-particle phase partitioning. To overcome these challenges, we have developed an open-path, eddy covariance NH3 instrument that minimizes these sampling issues. Eddy covariance measurements in 2015 and 2016 in the Rocky Mountain National Park (RMNP), Colorado showed the capabilities of the system to measure fluxes in clean and moderate-polluted regions. Interesting patterns of NH3 fluxes and NH3 concentration variations were observed, such as deposition of NH3 associated plumes from urban and agricultural areas and reemission of a similar magnitude when clean free-tropospheric air passing the site. Observed downward fluxes during midnight and upward fluxes in early morning also indicated NH3 fluxes related to dew formation and evaporation events. More details about these patterns and their relationships with ambient temperature, relative humidity, and other fluxes will be presented. These measurements also provided an opportunity to evaluate our current understanding of transport and deposition of NH3. Micrometeorological method, backward trajectory model, and bidirectional NH3 flux model were used to analyze observed variability of NH3 concentrations and fluxes. Implications of these results and how eddy covariance measurements combined with other measurements may provide insights to better quantify NH3 fluxes will be discussed.

  10. Sources of atmospheric ammonia

    International Nuclear Information System (INIS)

    Harriss, R.C.; Michaels, J.T.

    1982-01-01

    The information available on factors that influence emissions from the principal societal sources of ammonia to the atmosphere, namely combustion processes, volatilization of farm animal wastes, and volatilization of fertilizers, is reviewed. Emission factors are established for each major source of atmospheric ammonia. The factors are then multiplied by appropriate source characterization descriptors to obtain calculated fluxes of ammonia to the atmosphere on a state-by-state basis for the United States

  11. Inter-comparison of Flux-Gradient and Relaxed Eddy Accumulation Methods for Measuring Ammonia Flux Above a Corn Canopy in Central Illinois, USA

    Science.gov (United States)

    Nelson, A. J.; Koloutsou-Vakakis, S.; Rood, M. J.; Lichiheb, N.; Heuer, M.; Myles, L.

    2017-12-01

    Ammonia (NH3) is a precursor to fine particulate matter (PM) in the ambient atmosphere. Agricultural activities represent over 80% of anthropogenic emissions of NH3 in the United States. The use of nitrogen-based fertilizers contribute > 50% of total NH3 emissions in central Illinois. The U.S. EPA Science Advisory Board has called for improved methods to measure, model, and report atmospheric NH3 concentrations and emissions from agriculture. High uncertainties in the temporal and spatial distribution of NH3 emissions contribute to poor performance of air quality models in predicting ambient PM concentrations. This study reports and compares NH­3 flux measurements of differing temporal resolution obtained with two methods: relaxed eddy accumulation (REA) and flux-gradient (FG). REA and FG systems were operated concurrently above a corn canopy at the University of Illinois at Urbana-Champaign (UIUC) Energy Biosciences Institute (EBI) Energy Farm during the 2014 corn-growing season. The REA system operated during daytime, providing average fluxes over four-hour sampling intervals, where time resolution was limited by detection limit of denuders. The FG system employed a cavity ring-down spectrometer, and was operated continuously, reporting 30 min flux averages. A flux-footprint evaluation was used for quality control, resulting in 1,178 qualified FG measurements, 82 of which were coincident with REA measurements. Similar emission trends were observed with both systems, with peak NH3 emission observed one week after fertilization. For all coincident samples, mean NH3 flux was 205 ± 300 ng-N-m2s-1 and 110 ± 256 ng-N-m2s-1 as measured with REA and FG, respectively, where positive flux indicates emission. This is the first reported inter-comparison of REA and FG methods as used for quantifying NH3 fluxes from cropland. Preliminary analysis indicates the improved temporal resolution and continuous sampling enabled by FG allow for the identification of emission pulses

  12. Ammonia synthesis over multi-promoted iron catalysts obtained by high-energy ball-milling

    DEFF Research Database (Denmark)

    Jacobsen, C.J.H.; Jiang, Jianzhong; Mørup, Steen

    1999-01-01

    The feasibility of producing ammonia synthesis catalysts from high-energy ball-milling of a simple mixture of the constituent oxides has been investigated. The effect of ball-milling the fused oxidic precursor of the industrial KM1 ammonia synthesis catalyst has also been studied. The results show...

  13. Ph, Ammonia Flux, and Total Nitrogen in Duck Litter with Chemical Blends - A Field Study

    Directory of Open Access Journals (Sweden)

    TH Chung

    Full Text Available ABSTRACT This study was designed to evaluate the effects of chemical blend additives to duck litter on pH, ammonia (NH3 fluxes, total nitrogen (TN under a small pen trial. One hundred twenty 1-day-old duck (pekin were randomly assigned to 6 pens in a completely randomized design during 6 weeks. Control received no litter treatment whereas top-dressed treatment at rates of 50 g aluminum sulfate + 50 aluminum chloride/kg duck litter were mixed into the upper 1 cm of duck litter. Duck litter pH at 2 weeks through 5 weeks was significantly affected (p0.05 between treatments at 0 and 1 week. Reductions of NH3 fluxes at 3, 4, 5 and 6 weeks were 31, 16, 29 and 24%, respectively. Chemical blend treatments as a function of time resulted in increase in TN contents compared with control. There were no significant differences (p>0.05 in TN between treatments at 2 and 3 weeks, except for 4, 5 and 6 weeks. Chemical blend decreases NH3 fluxes and increases TN positively by reducing duck litter pH.

  14. Measurement and modeling of atmospheric flux of ammonia from dairy milking cow housing

    Science.gov (United States)

    Rumburg, Brian; Mount, George H.; Filipy, Jenny; Lamb, Brian; Westberg, Hal; Yonge, David; Kincaid, Ron; Johnson, Kristen

    Atmospheric ammonia (NH3) measurements are needed to better understand the impacts of NH3 emissions on aerosol formation and concentrations and anthropogenic changes to the N cycle. This paper describes concentration measurements of NH3 using differential optical absorption spectroscopy (DOAS), tracer ratio flux experiments, and development of a NH3 emissions model from a dairy milking cow free stall house with concrete floors. An area source tracer gas ratio method was used to determine NH3 fluxes which involved releasing SF6 as the tracer gas from the upwind edge of the stalls and measuring the tracer concentration downwind along with the DOAS NH3 measurements. The flux is calculated from the ratio of the NH3 and SF6 concentrations and the SF6 release rate and taking into account the differences in area and dispersion. The measured stall flux for the summers averaged 29±19gNH3cow-1h-1 at an average temperature of 18±5C. The emissions model calculated liquid NH3 concentrations in urine puddles, NH3 volatilization, theoretical and empirical mass transfer to the bulk atmosphere, and NH3 transport. The predicted concentrations were within ±30% using an empirical mass transfer coefficient and within ±41% using a theoretical mass transfer coefficient. Total annual NH3 emissions for the dairy of 185 milking cows was 7400 kg or 40kgNH3cow-1year-1, estimated total N excretions are 180kgcow-1year-1. This agrees with a N mass balance of the dairy. The model was very sensitive to urine puddle pH and also showed that emissions are temperature dependent.

  15. Measurements of ammonia concentrations, fluxes and dry deposition velocities to a spruce forest 1991-1995

    DEFF Research Database (Denmark)

    Andersen, H.V.; Hovmand, M.F.; Hummelshøj, P.

    1999-01-01

    and different meteorological situations. Different deposition characteristics were observed, depending on the ammonia concentration and the relative humidity. At conditions with westerly winds, the wind brings air masses from the North Sea with low concentration levels of ammonia to the site, while......, i.e. an ammonia concentration below which the trees and/or the surface emit ammonia due to an equilibrium with the ammonia inside the needles or on the surface. Emission of ammonia was also observed at relatively high ammonia concentration levels (above 2 mu g NH3-N m(-3)), mainly during one...... measuring period characterized by easterly winds with dry conditions and high ammonia concentrations, and the emissions might relate to evaporation from ammonia saturated surfaces or emission from mineralization in the forest soil. In general, relatively high net deposition velocities were observed during...

  16. Eddy covariance flux measurements of ammonia by high temperature chemical ionisation mass spectrometry

    Directory of Open Access Journals (Sweden)

    J. Sintermann

    2011-03-01

    Full Text Available A system for fast ammonia (NH3 measurements with chemical ionisation mass spectrometry (CIMS based on a commercial Proton Transfer Reaction-Mass Spectrometer (PTR-MS is presented. It uses electron transfer reaction as ionisation pathway and features a drift tube of polyetheretherketone (PEEK and silica-coated steel. Heating the instrumental inlet and the drift tube to 180 °C enabled an effective time resolution of ~1 s and made it possible to apply the instrument for eddy covariance (EC measurements. EC fluxes of NH3 were measured over two agricultural fields in Oensingen, Switzerland, following fertilisations with cattle slurry. Air was aspirated close to a sonic anemometer at a flow of 100 STP L min−1 and was directed through a 23 m long 1/2" PFA tube heated to 150 °C to an air-conditioned trailer where the gas was sub-sampled from the large bypass stream. This setup minimised damping of fast NH3 concentration changes between the sampling point and the actual measurement. High-frequency attenuation loss of the NH3 fluxes of 20 to 40% was quantified and corrected for using an empirical ogive method. The instrumental NH3 background signal showed a minor interference with H2O which was characterised in the laboratory. The resulting correction of the NH3 flux after slurry spreading was less than 1‰. The flux detection limit of the EC system was about 5 ng m−2 s−1 while the accuracy of individual flux measurements was estimated 16% for the high-flux regime during these experiments. The NH3 emissions after broad spreading of the slurry showed an initial maximum of 150 μg m−2 s−1 with a fast decline in the following hours.

  17. Measurements of ammonia concentrations, fluxes and dry deposition velocities to a spruce forest 1991-1995

    DEFF Research Database (Denmark)

    Andersen, H.V.; Hovmand, M.F.; Hummelshøj, P.

    1999-01-01

    measuring period characterized by easterly winds with dry conditions and high ammonia concentrations, and the emissions might relate to evaporation from ammonia saturated surfaces or emission from mineralization in the forest soil. In general, relatively high net deposition velocities were observed during...... at conditions with easterly winds, the air have passed central Jutland with large emission areas. Some of the relatively low deposition velocities or emissions were observed during conditions with low ammonia concentration and westerly winds. These observations might relate to a compensation point of the forest......, i.e. an ammonia concentration below which the trees and/or the surface emit ammonia due to an equilibrium with the ammonia inside the needles or on the surface. Emission of ammonia was also observed at relatively high ammonia concentration levels (above 2 mu g NH3-N m(-3)), mainly during one...

  18. Obtaining and Characterization of Flux-Based Products

    Directory of Open Access Journals (Sweden)

    Cosmina Maria Bogăţean

    2015-11-01

    Full Text Available The purpose of creating this assortment was to remind the public of a long forgotten sugar based product, with a high energy value and which can be easily associated both with plain or mineral water consumption. Also we have taken into consideration the well-known '' home-made'' and ''vintage'' concepts. The purpose of this scientific research is to obtain a laboratory created product, as well as obtaining both the cocoa and the lemon sorbet. In the technological process this type of products can be redefined under a new form. The great advantage comes with the fact that it dosen't currently exit on the market and so it can be considered as being a brand new product. The anbalyses both on the raw materials and on the final deliverable product were done in the Faculty's laboratories and it was proven to meet the standars.

  19. The annual ammonia budget of fertilised cut grassland – Part 1: Micrometeorological flux measurements and emissions after slurry application

    Directory of Open Access Journals (Sweden)

    C. Spirig

    2010-02-01

    Full Text Available Two commercial ammonia (NH3 analysers were customised to allow continuous measurements of vertical concentration gradients. The gradients were used to derive ammonia exchange fluxes above a managed grassland site at Oensingen (Switzerland by application of the aerodynamic gradient method. The measurements from July 2006 to October 2007 covered five complete growth-cut cycles and included six applications of liquid cattle slurry. The average accuracy of the flux measurements during unstable and near-neutral conditions was 20% and the detection limit was 10 ng NH3 m−2 s−1. Hence the flux measurements are considered sufficiently accurate for studying typical NH3 deposition rates over growing vegetation. Quantifying the overall emissions after slurry applications required the application of elaborate interpolations because of difficulties capturing the initial emissions during broadspreading of liquid manure. The emissions were also calculated with a mass balance method yielding similar fluxes. NH3 losses after slurry application expressed as percentage of emitted nitrogen versus applied total ammoniacal nitrogen (TAN varied between 4 and 19%, which is roughly a factor of three lower than the values for broadspreading of liquid manure in emission inventories. The comparatively low emission factors appear to be a consequence of the low dry matter content of the applied slurry and soil properties favouring ammonium adsorption.

  20. Metabolic flux rearrangement in the amino acid metabolism reduces ammonia stress in the α1-antitrypsin producing human AGE1.HN cell line.

    Science.gov (United States)

    Priesnitz, Christian; Niklas, Jens; Rose, Thomas; Sandig, Volker; Heinzle, Elmar

    2012-03-01

    This study focused on metabolic changes in the neuronal human cell line AGE1.HN upon increased ammonia stress. Batch cultivations of α(1)-antitrypsin (A1AT) producing AGE1.HN cells were carried out in media with initial ammonia concentrations ranging from 0mM to 5mM. Growth, A1AT production, metabolite dynamics and finally metabolic fluxes calculated by metabolite balancing were compared. Growth and A1AT production decreased with increasing ammonia concentration. The maximum A1AT concentration decreased from 0.63g/l to 0.51g/l. Central energy metabolism remained relatively unaffected exhibiting only slightly increased glycolytic flux at high initial ammonia concentration in the medium. However, the amino acid metabolism was significantly changed. Fluxes through transaminases involved in amino acid degradation were reduced concurrently with a reduced uptake of amino acids. On the other hand fluxes through transaminases working in the direction of amino acid synthesis, i.e., alanine and phosphoserine, were increased leading to increased storage of excess nitrogen in extracellular alanine and serine. Glutamate dehydrogenase flux was reversed increasingly fixing free ammonia with increasing ammonia concentration. Urea production additionally observed was associated with arginine uptake by the cells and did not increase at high ammonia stress. It was therefore not used as nitrogen sink to remove excess ammonia. The results indicate that the AGE1.HN cell line can adapt to ammonia concentrations usually present during the cultivation process to a large extent by changing metabolism but with slightly reduced A1AT production and growth. Copyright © 2012 Elsevier Inc. All rights reserved.

  1. Influence of gas-particle partitioning on ammonia and nitric acid fluxes above a deciduous forest in the Midwestern USA

    DEFF Research Database (Denmark)

    Hansen, Kristina; Sørensen, Lise Lotte; Hornsby, Karen E.

    diffusion denuders with detection by florescence and half-hourly flux measurements are calculated. HNO3 REA system is based on gas capture on sodium chloride (NaCl) coated denuders with subsequent analysis by ion-chromatography, and the resulting fluxes have a resolution of 3-4 hours. CO2 fluxes...... are measured by eddy covariance using a closed-path Licor LI-7500, while two MSP MOUDI-110 impactors are used to measure the 24-hourly average inorganic and 48 hourly averaged organic ion concentrations in 11 size bins, respectively, just above the canopy level (28 m). The results of this field campaign......Quantifying the atmosphere-biosphere exchange of reactive nitrogen gasses (including ammonia (NH3) and nitric acid (HNO3)) is crucial to assessing the impact of anthropogenic activities on natural and semi-natural ecosystems. However, measuring the deposition of reactive nitrogen is challenging due...

  2. The Effects of Manure Handling and Dietary Protein on Ammonia Fluxes from a Flush Dairy

    OpenAIRE

    Sparks, Jeffrey Allen

    2008-01-01

    Atmospheric ammonia (NH3(g)) poses an environmental concern mainly due its ability to form fine particulate matter (PM2.5 with a diameter smaller than 2.5 micrometers) in the form of ammonium nitrate (NH4NO3) and ammonium sulfate ([NH4]2SO4). These forms of PM2.5 may reduce visibility, contribute to eutrophication through deposition, and be detrimental to human health through inhalation. A more complete understanding of ammonia emissions may bring significant PM2.5 reductions within grasp. ...

  3. Improved passive flux samplers for measuring ammonia emissions from animal houses, part 1: Basic principles

    NARCIS (Netherlands)

    Scholtens, R.; Hol, J.M.G.; Wagemans, M.J.M.; Phillips, V.R.

    2003-01-01

    At present, precise, expensive and laborious methods with a high resolution in time are needed, to determine ammonia emission rates from animal houses. The high costs for equipment, maintenance and labour limit the number of sites that can be measured. This study examines a new, simpler concept for

  4. Ammonia flux above fertilized corn in central Illinois, USA, using relaxed eddy accumulation

    Science.gov (United States)

    The objective of this research is to quantify NH3 flux above an intensively managed cornfield in the Midwestern United States to improve understanding of NH3 emissions and evaluations of new and existing emission models. A relaxed eddy accumulation (REA) system was deployed above a corn canopy in ce...

  5. A Numerical Method for Obtaining Monoenergetic Neutron Flux Distributions and Transmissions in Multiple-Region Slabs

    Science.gov (United States)

    Schneider, Harold

    1959-01-01

    This method is investigated for semi-infinite multiple-slab configurations of arbitrary width, composition, and source distribution. Isotropic scattering in the laboratory system is assumed. Isotropic scattering implies that the fraction of neutrons scattered in the i(sup th) volume element or subregion that will make their next collision in the j(sup th) volume element or subregion is the same for all collisions. These so-called "transfer probabilities" between subregions are calculated and used to obtain successive-collision densities from which the flux and transmission probabilities directly follow. For a thick slab with little or no absorption, a successive-collisions technique proves impractical because an unreasonably large number of collisions must be followed in order to obtain the flux. Here the appropriate integral equation is converted into a set of linear simultaneous algebraic equations that are solved for the average total flux in each subregion. When ordinary diffusion theory applies with satisfactory precision in a portion of the multiple-slab configuration, the problem is solved by ordinary diffusion theory, but the flux is plotted only in the region of validity. The angular distribution of neutrons entering the remaining portion is determined from the known diffusion flux and the remaining region is solved by higher order theory. Several procedures for applying the numerical method are presented and discussed. To illustrate the calculational procedure, a symmetrical slab ia vacuum is worked by the numerical, Monte Carlo, and P(sub 3) spherical harmonics methods. In addition, an unsymmetrical double-slab problem is solved by the numerical and Monte Carlo methods. The numerical approach proved faster and more accurate in these examples. Adaptation of the method to anisotropic scattering in slabs is indicated, although no example is included in this paper.

  6. Obtaining GPR images of improved quality in karst as a result of an optimized processing flux

    Science.gov (United States)

    Oliveira, J. G. D., Jr.; Medeiros, W. E.; de Santana, F. L., Sr.; Bezerra, F. H.; Cazarin, C. L.

    2017-12-01

    Karst is a difficult environment for GPR imaging due to the strong effects of energy scattering caused by discontinuities and dissolution structures. In addition, conductive soil covers and adsorbed water in the geologic materials filling the dissolution voids can cause severe attenuation and dispersion. As a result of both effects, the GPR signal is strongly attenuated and dispersed as it propagates in the subsurface, so that the quality of images is usually very poor. We show that an adequate processing flux can result in images presenting improved quality. The key point of the processing approach is trying to recover the frequency content of the emitted GPR signal but keeping amplitude relationships along the traces. The processing flux is basically composed by seven steps: 1) static correction in order to obtain zero-offset traces, 2) Dewow to mitigate relatively very low frequency content, 3) spherical divergence correction, 4) spectral balancing, 5) migration, 6) bandpass frequency filtering, and finally 7) amplitude volume enhancement based on Hilbert transform. The resulting GPR images allow to identify sedimentary primary structures, including complex patterns as those ones associated to bioturbation, discontinuities as fractures and faults, dissolution structures, besides the infilling materials of these structures.

  7. Non-Uniqueness of the Geometry of Interplanetary Magnetic Flux Ropes Obtained from Model-Fitting

    Science.gov (United States)

    Marubashi, K.; Cho, K.-S.

    2015-12-01

    Since the early recognition of the important role of interplanetary magnetic flux ropes (IPFRs) to carry the southward magnetic fields to the Earth, many attempts have been made to determine the structure of the IPFRs by model-fitting analyses to the interplanetary magnetic field variations. This paper describes the results of fitting analyses for three selected solar wind structures in the latter half of 2014. In the fitting analysis a special attention was paid to identification of all the possible models or geometries that can reproduce the observed magnetic field variation. As a result, three or four geometries have been found for each of the three cases. The non-uniqueness of the fitted results include (1) the different geometries naturally stemming from the difference in the models used for fitting, and (2) an unexpected result that either of magnetic field chirality, left-handed and right-handed, can reproduce the observation in some cases. Thus we conclude that the model-fitting cannot always give us a unique geometry of the observed magnetic flux rope. In addition, we have found that the magnetic field chirality of a flux rope cannot be uniquely inferred from the sense of field vector rotation observed in the plane normal to the Earth-Sun line; the sense of rotation changes depending on the direction of the flux rope axis. These findings exert an important impact on the studies aimed at the geometrical relationships between the flux ropes and the magnetic field structures in the solar corona where the flux ropes were produced, such studies being an important step toward predicting geomagnetic storms based on observations of solar eruption phenomena.

  8. Obtaining absolute spatial flux measurements with a time-resolved pinhole camera

    International Nuclear Information System (INIS)

    Baker, K.L.; Porter, J.L.; Ruggles, L.E.; Fehl, D.L.; Chandler, G.A.; Vargas, M.; Mix, L.P.; Simpson, W.W.; Deeney, C.; Chrien, R.E.; Idzorek, G.C.

    1999-01-01

    A technique is described to determine the spatial x-ray flux emitted from a hohlraum wall and subsequently transmitted through a diagnostic hole. This technique uses x-ray diodes, bolometers, and a time-resolved pinhole camera to determine the spatial flux of x rays emitted through a hohlraum close-quote s diagnostic hole. The primary motivation for this analysis was the relatively long duration, nearly 100 ns, of the x-ray drive present in z-pinch driven hohlraums. This radiation causes plasma to ablate from the hohlraum walls surrounding the diagnostic hole and results in a partial obscuration that reduces the effective area over which diagnostics view the radiation. The effective change in area leads to an underestimation of the wall temperature when nonimaging diagnostics such as x-ray diodes and bolometers are used to determine power and later to infer a wall temperature. An analysis similar to the one described below is then necessary to understand the radiation environment present in x-ray driven hohlraums when these diagnostics are used and hole closure is important. copyright 1999 American Institute of Physics

  9. Measurements of nitric oxide and ammonia soil fluxes from a wet savanna ecosystem site in West Africa during the DACCIWA field campaign

    Science.gov (United States)

    Pacifico, Federica; Delon, Claire; Jambert, Corinne; Durand, Pierre; Morris, Eleanor; Evans, Mat J.; Lohou, Fabienne; Derrien, Solène; Donnou, Venance H. E.; Houeto, Arnaud V.; Reinares Martinez, Irene; Brilouet, Pierre-Etienne

    2018-03-01

    It is important to correctly simulate biogenic fluxes from soil in atmospheric chemistry models at a local and regional scale to study air pollution and climate in an area of the world, West Africa, that has been subject to a strong increase in anthropogenic emissions due to a massive growth in population and urbanization. Anthropogenic pollutants are transported inland and northward from the mega cities located on the coast, where the reaction with biogenic emissions may lead to enhanced ozone production outside urban areas, as well as secondary organic aerosols formation, with detrimental effects on humans, animals, natural vegetation and crops. Here we present field measurements of soil fluxes of nitric oxide (NO) and ammonia (NH3) observed over four different land cover types, i.e. bare soil, grassland, maize field and forest, at an inland rural site in Benin, West Africa, during the DACCIWA field campaign in June and July 2016. We observe NO fluxes up to 48.05 ngN m-2 s-1. NO fluxes averaged over all land cover types are 4.79 ± 5.59 ngN m-2 s-1, maximum soil emissions of NO are recorded over bare soil. NH3 is dominated by deposition for all land cover types. NH3 fluxes range between -6.59 and 4.96 ngN m-2 s-1. NH3 fluxes averaged over all land cover types are -0.91 ± 1.27 ngN m-2 s-1 and maximum NH3 deposition is measured over bare soil. The observations show high spatial variability even for the same soil type, same day and same meteorological conditions. We compare point daily average measurements of NO emissions recorded during the field campaign with those simulated by GEOS-Chem (Goddard Earth Observing System Chemistry Model) for the same site and find good agreement. In an attempt to quantify NO emissions at the regional and national scale, we also provide a tentative estimate of total NO emissions for the entire country of Benin for the month of July using two distinct methods: upscaling point measurements and using the

  10. Simple model for the prediction of ammonia volatilization from water basin: effect of water temperature and pH

    Directory of Open Access Journals (Sweden)

    Intamanee, J.

    2004-03-01

    Full Text Available Ammonia is a primary chemical used for preserving rubber latex. Consequently, the wastewater from concentrated rubber latex processing contains high ammonia concentration. The volatilization of ammonia from such wastewater may cause an air pollution problem such as the formation of an acid rain or an aerosol of ammonium nitrate and ammonium sulfate, which can seriously affect environment and human being. To assess the air pollution problem regarding atmospheric ammonia volatized from wastewater, the model for the prediction of ammonia volatilization rate and flux is therefore desirable. The purposes of this study were to investigate the effects of water temperature and pH on ammonia volatilization process and to develop a model to describe ammonia volatilization rate and flux including such effects.Ammonia volatilization from water was studied by using a volatilization tank (surface area = 780 cm2, volume = 7 L placed in a water bath in order to control the water temperature. The temperature and pH in the range of 25 to 50ºC and 5 to 11 were respectively investigated. The overall mass transfer coefficients of ammonia were measured as a function of temperature and pH. The quadratic multiple regression technique was used to obtain the model for mass transfer coefficient from experimental data. The model suggests that the overall mass transfer coefficient of ammonia increases with increasing water temperature and pH while the temperature-pH interaction retards the increasing characteristic of mass transfer coefficient. Thus the increasing in mass transfer coefficient at higher temperature and pH was slower than that at the lower one. The simple model for the prediction of ammonia volatilization rate and flux was developed based on mass transfer theory and mass transfer coefficient model obtained from this study. This simple ammonia emission model can be used to predict ammonia volatilization rate and flux at any pH, water temperature and

  11. Rejection of seamless pipe noise in magnetic flux leakage data obtained from gas pipeline inspection

    Science.gov (United States)

    Afzal, Muhammad; Udpa, Satish; Udpa, Lalita; Lord, William

    2000-05-01

    Natural gas is traditionally transmitted from production facilities to customer locations through a vast pipeline network. A major segment of this network employs seamless pipes. This is especially true for smaller diameter transmission and distribution lines. Manufacturing process associated with the production of seamless pipes contribute to a helical variation in the pipe along the axis. The deformation introduces an artifact in the data obtained from MFL inspection of these pipelines. This seamless pipe noise is usually correlated with signals generated by defects and other elements (joints, tees, etc.) in pipelines, and can therefore, mask their indications in MFL data. This warrants the need for methods to improve signal-to-noise ratio (SNR) in MFL data from seamless pipes. This paper presents a technique for detecting signals in MFL data from seamless pipes. The approach processes the data in various steps. First, a wavelet based denoising technique is applied to reduce the noise due to instrumentation and other sources. An adaptive filtering approach is then applied to reject seamless noise in the data. Since the inspection of pipelines typically generates vast amounts of data, it is imperative that the algorithm be computationally efficient. The processing method has to be robust in that it should be data independent. The approach described in this paper meet these criteria. Results from application of the approach to data from field tests are presented.

  12. Investigating sources of measured forest-atmosphere ammonia fluxes using two-layer bi-directional modelling

    DEFF Research Database (Denmark)

    Hansen, K.; Personne, E.; Skjøth, C.A.

    2017-01-01

    of the forest ecosystems, a period with full developed canopy (MMSF) and a senescent period for the DK-Sor site, with leaf fall and leaf litter build-up. Both datasets indicate emissions of NH3 from the forest to the atmosphere. The two-layer NH3 compensation point model SURFATM-NH3 was used in combination...... layer NH3 emission potential (Гg) was successfully applied using the plant area index (PAI) to represent the build-up of a litter layer in the leaf fall period. For a closed green forest canopy (MMSF), unaffected by agricultural NH3 sources, NH3 was emitted with daytime fluxes up to 50ng NH3-N m−2s−1...... and nighttime fluxes up to 30ng NH3-N m−2s−1. For a senescing forest (DK-Sor), located in an agricultural region, deposition rates of 250ng NH3-N m−2s−1 were measured prior to leaf fall, and emission rates up to 670ng NH3-N m−2s−1 were measured following leaf fall. For MMSF, simulated stomatal NH3 emissions...

  13. Flux

    DEFF Research Database (Denmark)

    Ravn, Ib

    . FLUX betegner en flyden eller strømmen, dvs. dynamik. Forstår man livet som proces og udvikling i stedet for som ting og mekanik, får man et andet billede af det gode liv end det, som den velkendte vestlige mekanicisme lægger op til. Dynamisk forstået indebærer det gode liv den bedst mulige...... kanalisering af den flux eller energi, der strømmer igennem os og giver sig til kende i vore daglige aktiviteter. Skal vores tanker, handlinger, arbejde, samvær og politiske liv organiseres efter stramme og faste regelsæt, uden slinger i valsen? Eller skal de tværtimod forløbe ganske uhindret af regler og bånd...

  14. Visualization of Crust in Metallic Piping Through Real-Time Neutron Radiography Obtained with Low Intensity Thermal Neutron Flux

    Directory of Open Access Journals (Sweden)

    Leandro C. Luiz

    2017-06-01

    Full Text Available The presence of crust on the inner walls of metallic ducts impairs transportation because crust completely or partially hinders the passage of fluid to the processing unit and causes damage to equipment connected to the production line. Its localization is crucial. With the development of the electronic imaging system installed at the Argonauta/Nuclear Engineering Institute (IEN/National Nuclear Energy Commission (CNEN reactor, it became possible to visualize crust in the interior of metallic piping of small diameter using real-time neutron radiography images obtained with a low neutron flux. The obtained images showed the resistance offered by crust on the passage of water inside the pipe. No discrepancy of the flow profile at the bottom of the pipe, before the crust region, was registered. However, after the passage of liquid through the pipe, images of the disturbances of the flow were clear and discrepancies in the flow profile were steep. This shows that this technique added the assembled apparatus was efficient for the visualization of the crust and of the two-phase flows.

  15. Visualization of crust in metallic piping through real-time neutron radiography obtained with low intensity thermal neutron flux

    Energy Technology Data Exchange (ETDEWEB)

    Luiz, Leandro C.; Crispim, Verginia R. [Nuclear Engineering Program, Federal University of Rio de Janeiro, Rio de Janeiro (Brazil); Ferreira, Francisco J. O. [National Nuclear Energy Commission, CNEN/IEN, Division Reactors, Rio de Janeiro (Brazil)

    2017-06-15

    The presence of crust on the inner walls of metallic ducts impairs transportation because crust completely or partially hinders the passage of fluid to the processing unit and causes damage to equipment connected to the production line. Its localization is crucial. With the development of the electronic imaging system installed at the Argonauta/Nuclear Engineering Institute (IEN)/National Nuclear Energy Commission (CNEN) reactor, it became possible to visualize crust in the interior of metallic piping of small diameter using real-time neutron radiography images obtained with a low neutron flux. The obtained images showed the resistance offered by crust on the passage of water inside the pipe. No discrepancy of the flow profile at the bottom of the pipe, before the crust region, was registered. However, after the passage of liquid through the pipe, images of the disturbances of the flow were clear and discrepancies in the flow profile were steep. This shows that this technique added the assembled apparatus was efficient for the visualization of the crust and of the two-phase flows.

  16. Visualization of crust in metallic piping through real-time neutron radiography obtained with low intensity thermal neutron flux

    International Nuclear Information System (INIS)

    Luiz, Leandro C.; Crispim, Verginia R.; Ferreira, Francisco J. O.

    2017-01-01

    The presence of crust on the inner walls of metallic ducts impairs transportation because crust completely or partially hinders the passage of fluid to the processing unit and causes damage to equipment connected to the production line. Its localization is crucial. With the development of the electronic imaging system installed at the Argonauta/Nuclear Engineering Institute (IEN)/National Nuclear Energy Commission (CNEN) reactor, it became possible to visualize crust in the interior of metallic piping of small diameter using real-time neutron radiography images obtained with a low neutron flux. The obtained images showed the resistance offered by crust on the passage of water inside the pipe. No discrepancy of the flow profile at the bottom of the pipe, before the crust region, was registered. However, after the passage of liquid through the pipe, images of the disturbances of the flow were clear and discrepancies in the flow profile were steep. This shows that this technique added the assembled apparatus was efficient for the visualization of the crust and of the two-phase flows

  17. Ammonia production from amino acid-based biomass-like sources by engineered Escherichia coli.

    Science.gov (United States)

    Mikami, Yosuke; Yoneda, Hisanari; Tatsukami, Yohei; Aoki, Wataru; Ueda, Mitsuyoshi

    2017-12-01

    The demand for ammonia is expected to increase in the future because of its importance in agriculture, industry, and hydrogen transportation. Although the Haber-Bosch process is known as an effective way to produce ammonia, the process is energy-intensive. Thus, an environmentally friendly ammonia production process is desired. In this study, we aimed to produce ammonia from amino acids and amino acid-based biomass-like resources by modifying the metabolism of Escherichia coli. By engineering metabolic flux to promote ammonia production using the overexpression of the ketoisovalerate decarboxylase gene (kivd), derived from Lactococcus lactis, ammonia production from amino acids was 351 mg/L (36.6% yield). Furthermore, we deleted the glnA gene, responsible for ammonia assimilation. Using yeast extract as the sole source of carbon and nitrogen, the resultant strain produced 458 mg/L of ammonia (47.8% yield) from an amino acid-based biomass-like material. The ammonia production yields obtained are the highest reported to date. This study suggests that it will be possible to produce ammonia from waste biomass in an environmentally friendly process.

  18. Ammonia intoxication

    International Nuclear Information System (INIS)

    Bessman, S.P.; Pal, N.

    1982-01-01

    Data is presented which shows that there is a relation between ammonia concentration in the blood and state of consciousness. The concentrations of GTP and ATP also relate both to the ammonia concentration in blood and the state of consciousness. The rate of protein synthesis in the brain as measured by the percent of intracellular counts that are incorporated into protein is also related to ammonia concentration. These findings of energy depletion and depressed synthesis resulting from energy depletion suggest that the primary lesion in ammonia intoxication involves the Krebs cycle. The greater effect of ammonia on GTP than on ATP metabolism supports the view that the primary site of action of ammonia is at the glutamate dehydrogenase-ketoglutarate reduction step - and is consistent with previous work on this subject. (H.K.)

  19. Ammonia Monitor

    Science.gov (United States)

    Sauer, Richard L. (Inventor); Akse, James R. (Inventor); Thompson, John O. (Inventor); Atwater, James E. (Inventor)

    1999-01-01

    Ammonia monitor and method of use are disclosed. A continuous, real-time determination of the concentration of ammonia in an aqueous process stream is possible over a wide dynamic range of concentrations. No reagents are required because pH is controlled by an in-line solid-phase base. Ammonia is selectively transported across a membrane from the process stream to an analytical stream to an analytical stream under pH control. The specific electrical conductance of the analytical stream is measured and used to determine the concentration of ammonia.

  20. Detailed study of the plasma-activated catalytic generation of ammonia in N2-H2 plasmas

    Science.gov (United States)

    van Helden, J. H.; Wagemans, W.; Yagci, G.; Zijlmans, R. A. B.; Schram, D. C.; Engeln, R.; Lombardi, G.; Stancu, G. D.; Röpcke, J.

    2007-02-01

    We investigated the efficiency and formation mechanism of ammonia generation in recombining plasmas generated from mixtures of N2 and H2 under various plasma conditions. In contrast to the Haber-Bosch process, in which the molecules are dissociated on a catalytic surface, under these plasma conditions the precursor molecules, N2 and H2, are already dissociated in the gas phase. Surfaces are thus exposed to large fluxes of atomic N and H radicals. The ammonia production turns out to be strongly dependent on the fluxes of atomic N and H radicals to the surface. By optimizing the atomic N and H fluxes to the surface using an atomic nitrogen and hydrogen source ammonia can be formed efficiently, i.e., more than 10% of the total background pressure is measured to be ammonia. The results obtained show a strong similarity with results reported in literature, which were explained by the production of ammonia at the surface by stepwise addition reactions between adsorbed nitrogen and hydrogen containing radicals at the surface and incoming N and H containing radicals. Furthermore, our results indicate that the ammonia production is independent of wall material. The high fluxes of N and H radicals in our experiments result in a passivated surface, and the actual chemistry, leading to the formation of ammonia, takes place in an additional layer on top of this passivated surface.

  1. Ammonia blood test

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003506.htm Ammonia blood test To use the sharing features on this page, ... Encephalopathy - ammonia; Cirrhosis - ammonia; Liver failure - ammonia Images Blood test References Chernecky CC, Berger BJ. Ammonia (NH3) - blood ...

  2. Comparison of neutron fluxes obtained by 2-D and 3-D geometry with different shielding libraries in biological shield of the TRIGA MARK II reactor

    International Nuclear Information System (INIS)

    Bozic, M.; Zagar, T.; Ravnik, M.

    2003-01-01

    Neutron fluxes in different spatial locations in biological shield are obtained with TORT code (TORT-Three Dimensional Oak Ridge Discrete Ordinates Neutron/Photon Transport Code). Libraries used with TORT code were BUGLE-96 library (coupled library with 47 neutron groups and 20 gamma groups) and VITAMIN-B6 library (coupled library with 199 neutron groups and 42 gamma groups). BUGLE-96 library is derived from VITAMIN-B6 library. 2-D and 3-D models for homogeneous type of problem (without inserted beam port 4) and problem with asymmetry (non-homogeneous problem; inserted beam port 4, filled with different materials) were of interest for neutron flux calculation. The main purpose is to verify the possibility for using 2-D approximation model instead of large 3-D model in some calculations. Another purpose of this paper was to compare neutron spectral constants obtained from neutron fluxes (3-D model) determined with smaller BUGLE-96 library with new constants obtained from fluxes calculated with bigger VITAMIN-B6 library. These neutron spectral constants are used in isotopic calculation with SCALE code package (ORIGEN-S). In past only neutron spectral constants determined by neutron fluxes from BUGLE-96 library were used. Experimental results used for isotopic composition comparison are available from irradiation experiment with selected type of concrete and other materials in beam port 4 (irradiation channel 4) in TRIGA Mark II reactor. These experimental results were used as a benchmark in this paper. (author)

  3. Modeling the effect of heat fluxes on ammonia and nitrous oxide emissions from an anaerobic swine waste treatment lagoon using artificial neural network

    Science.gov (United States)

    Understanding factors that affect ammonia and nitrous emissions from anaerobic swine waste treatment lagoons or any animal waste receptacles is a necessary first step in deploying potential remediation options. In this study, we examined the various meteorological factors (i.e., air temperatures, s...

  4. The final power calibration of the IPEN/MB-01 nuclear reactor for various configurations obtained from the measurements of the absolute average neutron flux

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Alexandre Fonseca Povoa da, E-mail: alexandre.povoa@mar.mil.br [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), Sao Paulo, SP (Brazil); Bitelli, Ulysses d' Utra; Mura, Luiz Ernesto Credidio; Lima, Ana Cecilia de Souza; Betti, Flavio; Santos, Diogo Feliciano dos, E-mail: ubitelli@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    The use of neutron activation foils is a widely spread technique applied to obtain nuclear parameters then comparing the results with those calculated using specific methodologies and available nuclear data. By irradiation of activation foils and subsequent measurement of its induced activity, it is possible to determine the neutron flux at the position of irradiation. The power level during operation of the reactor is a parameter which is directly proportional to the average neutron flux throughout the core. The objective of this work is to gather data from irradiation of gold foils symmetrically placed along a cylindrically configured core which presents only a small excess reactivity in order to derive the power generated throughout the spatial thermal and epithermal neutron flux distribution over the core of the IPEN/MB-01 Nuclear Reactor, eventually lending to a proper calibration of its nuclear channels. The foils are fixed in a Lucite plate then irradiated with and without cadmium sheaths so as to obtain the absolute thermal and epithermal neutron flux. The correlation between the average power neutron flux resulting from the gold foils irradiation, and the average power digitally indicated by the nuclear channel number 6, allows for the calibration of the nuclear channels of the reactor. The reactor power level obtained by thermal neutron flux mapping was (74.65 ± 2.45) watts to a mean counting per seconds of 37881 cps to nuclear channel number 10 a pulse detector, and 0.719.10{sup -5} ampere to nuclear linear channel number 6 (a non-compensated ionization chamber). (author)

  5. Shigella reroutes host cell central metabolism to obtain high-flux nutrient supply for vigorous intracellular growth

    Science.gov (United States)

    Kentner, David; Martano, Giuseppe; Callon, Morgane; Chiquet, Petra; Brodmann, Maj; Burton, Olga; Wahlander, Asa; Nanni, Paolo; Delmotte, Nathanaël; Grossmann, Jonas; Limenitakis, Julien; Schlapbach, Ralph; Kiefer, Patrick; Vorholt, Julia A.; Hiller, Sebastian; Bumann, Dirk

    2014-01-01

    Shigella flexneri proliferate in infected human epithelial cells at exceptionally high rates. This vigorous growth has important consequences for rapid progression to life-threatening bloody diarrhea, but the underlying metabolic mechanisms remain poorly understood. Here, we used metabolomics, proteomics, and genetic experiments to determine host and Shigella metabolism during infection in a cell culture model. The data suggest that infected host cells maintain largely normal fluxes through glycolytic pathways, but the entire output of these pathways is captured by Shigella, most likely in the form of pyruvate. This striking strategy provides Shigella with an abundant favorable energy source, while preserving host cell ATP generation, energy charge maintenance, and survival, despite ongoing vigorous exploitation. Shigella uses a simple three-step pathway to metabolize pyruvate at high rates with acetate as an excreted waste product. The crucial role of this pathway for Shigella intracellular growth suggests targets for antimicrobial chemotherapy of this devastating disease. PMID:24958876

  6. Shigella reroutes host cell central metabolism to obtain high-flux nutrient supply for vigorous intracellular growth.

    Science.gov (United States)

    Kentner, David; Martano, Giuseppe; Callon, Morgane; Chiquet, Petra; Brodmann, Maj; Burton, Olga; Wahlander, Asa; Nanni, Paolo; Delmotte, Nathanaël; Grossmann, Jonas; Limenitakis, Julien; Schlapbach, Ralph; Kiefer, Patrick; Vorholt, Julia A; Hiller, Sebastian; Bumann, Dirk

    2014-07-08

    Shigella flexneri proliferate in infected human epithelial cells at exceptionally high rates. This vigorous growth has important consequences for rapid progression to life-threatening bloody diarrhea, but the underlying metabolic mechanisms remain poorly understood. Here, we used metabolomics, proteomics, and genetic experiments to determine host and Shigella metabolism during infection in a cell culture model. The data suggest that infected host cells maintain largely normal fluxes through glycolytic pathways, but the entire output of these pathways is captured by Shigella, most likely in the form of pyruvate. This striking strategy provides Shigella with an abundant favorable energy source, while preserving host cell ATP generation, energy charge maintenance, and survival, despite ongoing vigorous exploitation. Shigella uses a simple three-step pathway to metabolize pyruvate at high rates with acetate as an excreted waste product. The crucial role of this pathway for Shigella intracellular growth suggests targets for antimicrobial chemotherapy of this devastating disease.

  7. Synthesis of ammonia with microwave plasma

    International Nuclear Information System (INIS)

    Xu Wenguo; Yu Aimin; Liu Jun; Jin Qinhan

    1991-01-01

    THe synthesis of ammonia absorbed on 13X zeolite with the aid of microwave plasma is described. The ammonia molecule absorbed on 13X zeolite as ammonium ions were detected by IR spectroscopy. The results obtained show that the ammonia synthesis is facilitated by the surface reactions of NH x (x = 1, 2) radicals adsorbed on zeolite with hydrogen atoms

  8. Haber Process for Ammonia Synthesis

    Indian Academy of Sciences (India)

    C in order to obtain even a small percentage of ammonia. For this temperature range, however, no catalyst was available. By increasing the pressure to 75 bar the equilibrium conditions improved, but even at this pressure, and an operating.

  9. First In-Core Simultaneous Measurements of Nuclear Heating and Thermal Neutron Flux Obtained With the Innovative Mobile Calorimeter CALMOS Inside the OSIRIS Reactor

    Science.gov (United States)

    Carcreff, Hubert; Salmon, Laurent; Bubendorff, Jacques; Lepeltier, Valérie

    2016-10-01

    Nuclear heating inside a MTR reactor has to be known in order to design and run irradiation experiments which have to fulfill target temperature constraints. This measurement is usually carried out by calorimetry. The innovative calorimetric system, CALMOS, has been studied and built in 2011 for the 70MWth OSIRIS reactor operated by CEA. Thanks to a new type of calorimetric probe, associated to a specific displacement system, it provides measurements along the fissile height and above the core. Calorimeter working modes, measurement procedures, main modeling and experimental results and expected advantages of this new technique have been already presented in previous papers. However, these first in-core measurements were not performed beyond 6 W · g-1, due to an inside temperature limitation imposed by a safety authority requirement. In this paper, we present the first in-core simultaneous measurements of nuclear heating and conventional thermal neutron flux obtained by the CALMOS device at 70 MW nominal reactor power. For the first time, this experimental system was operated in nominal in-core conditions, with nominal neutron flux up to 2.7 1014 n · cm-2 · s-1 and nuclear heating up to 12 W · g-1. After a brief reminder of the calorimetric cell configuration and displacement system specificities, first nuclear heating distributions at nominal power are presented and discussed. In order to reinforce the heating evaluation, a comparison is made between results obtained by the probe calibration coefficient and the zero methods. Thermal neutron flux evaluation from SPND signal processing required a specific TRIPOLI-4 Monte Carlo calculation which has been performed with the precise CALMOS cell geometry. In addition, the Finite Element model for temperatures map prediction inside the calorimetric cell has been upgraded with recent experimental data obtained up to 12 W · g-1. Finally, the experience feedback led us to improvement perspectives. A second device is

  10. New findings on cerebral ammonia uptake in HE using functional (13)N-ammonia PET.

    Science.gov (United States)

    Sørensen, Michael; Keiding, Susanne

    2007-12-01

    PET is a functional imaging technique suitable for studies of brain ammonia metabolism. Dynamic (13)N-ammonia PET yields time-courses of radioactivity concentrations in brain (PET camera) and blood (samples). Ahl et al. (Hepatology 40:73-79, 2004) and Keiding et al. (Hepatology 43:42-50, 2006) analysed such data in patients with HE by a kinetic model accounting for transfer of (13)N-ammonia across the blood-brain barrier (BBB) and intracellular formation of (13)N-glutamine. Initial unidirectional (13)N-ammonia transfer across BBB was characterized by the permeability-surface area product PS(BBB) (ml blood min(-1) ml(-1) tissue). There was a tendency to lower PS(BBB) values in patients with cirrhosis and HE than in patients with cirrhosis without HE and healthy controls but the differences were not statistically significant. Keiding et al. (Hepatology 43:42-50, 2006) also calculated PS(met) (ml blood min(-1) ml(-1) tissue) as a measure of the combined transfer of (13)N-ammonia across BBB and subsequent intracellular metabolism of (13)N-ammonia; neither did this PS-value show significant difference between the groups of subjects. Net flux of ammonia from blood into intracellular metabolites was linearly correlated to arterial ammonia. In conclusion, basic brain ammonia kinetics was not changed significantly in patients with cirrhosis +/- HE compared to healthy controls. Blood ammonia seems to be the more important factor for increased brain ammonia uptake in HE.

  11. Ammonia abundances in comets

    Science.gov (United States)

    Wyckoff, S.; Tegler, S.; Engel, L.

    The emission band strengths of the NH2 bands of Comets Halley, Hartley-Good, Thiele, and Borrelly were measured to determine the NH2 column densities for the comets. Production rates obtained using the Haser and vectorial models are in agreement within the observational errors, suggesting that a simple two-step decay model may be used to approximate the NH2 distribution in a comet's coma. Ammonia-to-water abundance ratios from 0.01 to 0.4 percent were found for the four comets. The ratio in Comet Halley is found to be Q(NH3)/Q(H2O) = 0.002 + or - 0.001. No significant difference in the ammonia abundance was found before or after perihelion in Comet Halley.

  12. Acidification of pig slurry effects on ammonia and nitrous oxide emissions, nitrate leaching, and perennial ryegrass regrowth as estimated by N-urea flux

    Directory of Open Access Journals (Sweden)

    Sang Hyun Park

    2018-03-01

    Full Text Available Objective The present study aimed to assess the nitrogen (N use efficiency of acidified pig slurry for regrowth yield and its environmental impacts on perennial ryegrass swards. Methods The pH of digested pig slurry was adjusted to 5.0 or 7.0 by the addition of sulfuric acid and untreated as a control. The pig slurry urea of each treatment was labeled with 15N urea and applied at a rate of 200 kg N/ha immediately after cutting. Soil and herbage samples were collected at 7, 14, and 56 d of regrowth. The flux of pig slurry-N to regrowth yield and soil N mineralization were analyzed, and N losses via NH3, N2O emission and NO3− leaching were also estimated. Results The pH level of the applied slurry did not have a significant effect on herbage yield or N content of herbage at the end of regrowth, whereas the amount of N derived from pig slurry urea (NdfSU was higher in both herbage and soils in pH-controlled plots. The NH4+-N content and the amount of N derived from slurry urea into soil NH4+ fraction (NdfSU-NH4+ was significantly higher in in the pH 5 plot, whereas NO3− and NdfSU-NO3− were lower than in control plots over the entire regrowth period. Nitrification of NH4+-N was delayed in soil amended with acidified slurry. Compared to non-pH-controlled pig slurry (i.e. control plots, application of acidified slurry reduced NH3 emissions by 78.1%, N2O emissions by 78.9% and NO3− leaching by 17.81% over the course of the experiment. Conclusion Our results suggest that pig slurry acidification may represent an effective means of minimizing hazardous environmental impacts without depressing regrowth yield.

  13. A new method to obtain minute interval mass fluxes of H2O and CO2 using scintillometry and scalar turbulence measurements

    NARCIS (Netherlands)

    Kesteren, van A.J.H.; Hartogensis, O.K.; Dinther, van D.; Moene, A.F.; Graf, A.

    2012-01-01

    The goal of this study is to test an alternative method for determining turbulent H2O and CO2 fluxes, which has a faster statistical convergence than the classical eddy-covariance method. This enables determining turbulent fluxes during strongly non-stationary conditions, e.g. in the intermittent

  14. Calibration of the nuclear power channels for the cylindrical configuration of the IPEN/MB-01 reactor obtained from the measurements of the spatial neutron flux distribution in the reactor core through the irradiation of gold foils

    Energy Technology Data Exchange (ETDEWEB)

    Bitelli, Ulysses d' Utra; Silva, Alexandre F. Povoa da; Mura, Luiz Ernesto Credidio; Aredes, Vitor Ottoni Garcia; Santos, Diogo Feliciano dos, E-mail: ubitelli@ipen.br, E-mail: alexpovoa@yahoo.com.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    The activation foil is one of the most used techniques to obtain and compare nuclear parameters from the nuclear data libraries, given by a gamma spectrometry system. Through the measurements of activity induced in the foils, it is possible to determine the neutron flux profile exactly where it has been irradiated. The power level operation of the reactor is a parameter directly proportional to the average neutron flux in the core. The objective of this work is to obtain, for a cylindrical configuration, the power generation through a spatial thermal neutron flux distribution in the core of IPEN/MB-01 Reactor, by irradiating gold foils positioned symmetrically into the core. They are put in a Lucite plate which will not interfere in the analysis of the neutron flux, because of its low microscopic absorption cross section for the analyzed neutrons. The foils are irradiated with and without cadmium covered small plates, to obtain the thermal and epithermal neutron flux, through specific equations. The correlation between the average power neutron flux, as a result of the foil's irradiation, and the average power digital neutron flux of the nuclear power channels, allows the calibration of the nuclear channels of the reactor. This same correlation was done in 2008 with the reactor in a rectangular configuration, which resulted in a specific calibration of the power level operation. This calibration cannot be used in the cylindrical configuration, because the nuclear parameters could change, which may lead to a different neutron profile. Furthermore, the precise knowledge of the power neutron flux in the core also validates the mathematics used to calculate the power neutron flux. (author)

  15. Measurement of atmospheric ammonia at a dairy using differential optical absorption spectroscopy in the mid-ultraviolet

    Science.gov (United States)

    Mount, George H.; Rumburg, Brian; Havig, Jeff; Lamb, Brian; Westberg, Hal; Yonge, David; Johnson, Kristen; Kincaid, Ronald

    Ammonia is the most abundant basic gas in the atmosphere, and after N 2 and N 2O is the most abundant nitrogen-containing specie (Seinfeld and Pandis, 1998. Atmospheric Chemistry and Physics: from air pollution to climate changes. Wiley, New York). Typical concentrations of ammonia in the boundary layer range from environmental concern. In the US, ≈85% of ammonia emissions come from livestock operations (EPA Trends, 1998. www.epa.gov/ttn/chief/trends98/chapter2.pdf). Dairy farms constitute a large fraction of the livestock inventory. Current estimates of ammonia emissions to the atmosphere are characterized by a high degree of uncertainty, and so it is very important to obtain better estimates of ammonia emissions. We are working at the Washington State University research dairy to quantify ammonia emissions and investigate the effects of various mitigation strategies on those emissions. We describe here a new instrument utilizing the differential optical absorption spectroscopy (DOAS) technique to measure ammonia in the mid-ultraviolet with a detectability limit of about 1 ppb. DOAS avoids many of the problems that have thwarted past ammonia concentration measurements. Initial results show concentrations in the barn/concrete yard areas in the tens of parts per million range, over the slurry lagoons of hundreds of parts per billion to low parts per million, and low parts per million levels after initial slurry applications onto pastureland. Future papers will report on emission fluxes from the various parts of the dairy and the results of mitigation strategies; we show here initial data results. For a recent review of ammonia volatilization from dairy farms, see Bussink and Oenema (Nutrient Cycling in Agroecosystems 51(1998) 19).

  16. Aquatic Life Criteria - Ammonia

    Science.gov (United States)

    Documents related to EPA's final 2013 Aquatic Life Ambient Water Quality Criteria for Ammonia (Freshwater). These documents pertain to the safe levels of Ammonia in water that should protect to the majority of species.

  17. Ammonia transformation in a biotrickling air filter

    DEFF Research Database (Denmark)

    Nielsen, Lars Peter; Nielsen, Marie Louise; Andersen, Mathias

    2007-01-01

    A simple, tubular biotrickling filter was designed for optimal removal of ammonia and odour in ventilation air from a pig house. The removal and transformation of ammonia was studied in detail by analysis and modelling of chemical gradients through the filter. Good correspondence between...... measurements and model was obtained by using conventional substrate and inhibition kinetics of ammonium and nitrite oxidizing bacteria. Highest rates of ammonia removal were observed in the central section of the filter. Near the air outlet and water inlet the process was ammonia limited, while high nitrous...... acid concentrations almost excluded any biological activity near the air inlet and water outlet. Nitrous acid inhibition also stabilized pH at 6.5-7 all through the filter. Being sensitive to both ammonia and nitrous acid the nitrite oxidation process occurred mainly in the filter sections near the air...

  18. Contents and implications of ammonia human and canine bile.

    Science.gov (United States)

    Alderete, J S; Gaines, E L; Hudson, N L

    1978-08-01

    The quantification and physiological significance of ammonia in human and canine bile has not been clearly documented or analyzed previously. Bile from the gallbladder, common hepatic duct, and from T-tubes obtained from patients undergoing cholecystectomy and choledochotomy. Similar samples were obtained in 6 dogs by cannulation of their hepatic duct and various blood vessels. Simultaneous blood and bile samples were obtained at 15-min intervals before during, and after an exogenous load of ammonia, given intravenously. Ammonia levels were measured in all samples. Ammonia was measurable by conventional methods in human and canine bile. In both species the gallbladder bile contained at least twice as much ammonia as bile from the common hepatic duct. After an exogenous ammonia load, the levels of ammonia in canine bile increased in similar patterns, but in lesser magnitude than the ammonia levels measured at several sites in the circulation. The findings document that the bile contains ammonia in different quantities and suggest that bile could be an additional pathway for the removal of ammonia by the liver, in addition to the urea cycle. The loss of the biliary pathway for ammonia excretion could contribute to the pathophysiology of the signs and symptoms attributed to hyperammoniemia occurring in human beings and dogs with decreased hepatic function.

  19. Calibration of the nuclear power channels of the IPEN/MB-01 reactor obtained from the measurements of the spatial thermal neutron flux distribution in the reactor core through the irradiation of infinitely diluted gold foils

    International Nuclear Information System (INIS)

    Goncalves, Lucas Batista

    2008-01-01

    Several nuclear parameters are obtained through the gamma spectrometry of targets irradiated in a research reactor core and this is the case of the activation foils which make possible, through the measurements of the activity induced, to determine the neutron flux in the place where they had been irradiated. The power level operation of the reactor is a parameter directly proportional to the average neutron flux in the core. This work aims to get the power operation of the reactor through of spatial neutron flux distribution in the core of IPEN/MB-01 reactor by the irradiation of infinitely diluted gold foils and prudently located in its interior. These foils were made in the form of metallic alloy in concentration levels such that the phenomena of flux disturbance, as the self-shielding factors to neutrons become worthless. These activation foils has only 1% of dispersed gold atoms in an aluminium matrix content of 99% of this element. The irradiations of foils have been carried through with and without cadmium plate. The total correlation between the average thermal neutron flux obtained by irradiation of infinitely diluted activation foils and the average digital value of current of the nuclear power channels 5 and 6 (non-compensated ionization chambers - CINC), allow the calibration of the nuclear channels of the IPEN/MB-01 reactor. (author)

  20. Strong Evidence of Variable Micro-meteor Flux from Apollo 17 Samples Obtained at Shorty Crater and on the Light Mantle Avalanche at Taurus-Littrow

    Science.gov (United States)

    Schmitt, H. H.; Petro, N. E.

    2017-12-01

    Light-gray regolith overlying the orange and black pyroclastic ash (Schmitt, 2017) at Shorty Crater protected the ash from incorporation into surrounding basaltic regolith for 3.5 billion years (Tera and Wasserburg, 1976; Saito and Alexander, 1979). Inspection of LROC images indicate this regolith probably came from a 350 m diameter, degraded impact crater (Fitzgibbon Crater), about 1 km NNE of Shorty. This regolith was derived largely from basalt and spread over the ash deposit about 24 Myr (Eugster, et al., 1979, corrected for post-Shorty exposure) after the last ash eruption. Maturity indexes for light gray regolith samples 74441 and 74461 are about 8 (Morris, 1978) and agglutinate concentrations are 8% and 7.7% (Heiken and McKay, 1974), respectively. These values are inconsistent with the exposure and cycling of the light-gray regolith during 3.5 billion years in the lunar surface impact environment (i.e., the time between ash deposition and the light mantle avalanche). If agglutinate content and Is/FeO indexes largely reflect the cumulative effect of micro-meteor impacts, as generally concluded, the light-gray regolith formed in an environment with significantly less micro-meteor flux than that which has prevailed more recently. 14-18% of fragile, ropy glass in the light-gray regolith, as compared with meteor flux during development. The high recent micro-meteor flux appears to have existed for at least for the last 75 million years (Schmitt, et al., 2017), the estimated time using LROC-based crater frequency analysis (van der Bogert, et al., 2012) since the light mantle avalanche of South Massif regolith covered the light-gray regolith. New regolith on the light mantle appears to be developing a higher concentration of agglutinates and a higher maturity index relative to regolith in deeper portions of the unit. Light mantle avalanche samples 73141 (subsurface) and 73121 (near surface), have agglutinates at 32% and 42% and Is/FeO indexes of 48 and 78

  1. Power-to-ammonia: rethinking the role of ammonia – from a value product to a flexible energy carrier (FlexNH3)

    NARCIS (Netherlands)

    Yasmina Bennani; Anish Patil; Christian E.J. van Someren; András Perl; Leo J.M. Heijne

    2016-01-01

    This report focuses on the feasibility of the power-to-ammonia concept. Power-to-ammonia uses produced excess renewable electricity to electrolyze water, and then to react the obtained hydrogen with nitrogen, which is obtained through air separation, to produce ammonia. This process may be used as a

  2. Catalyst for Ammonia Oxidation

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a bimetallic catalyst for ammonia oxidation, a method for producing a bimetallic catalyst for ammonia oxidation and a method for tuning the catalytic activity of a transition metal. By depositing an overlayer of less catalytic active metal onto a more catalytic...

  3. Method for forming ammonia

    Science.gov (United States)

    Kong, Peter C.; Pink, Robert J.; Zuck, Larry D.

    2008-08-19

    A method for forming ammonia is disclosed and which includes the steps of forming a plasma; providing a source of metal particles, and supplying the metal particles to the plasma to form metal nitride particles; and providing a substance, and reacting the metal nitride particles with the substance to produce ammonia, and an oxide byproduct.

  4. Use of refractory chromites for obtaining fluxes amassed employed in submerged arc welding (SAW); Empleo de cromitas refractarias par la obtencion de fundentes aglomerados utilizados en la soldadura automatica por arco sumegido (SAW)

    Energy Technology Data Exchange (ETDEWEB)

    Perdomo-Gonzalez, L.; Quintana-Puchol, R.; Cruz-Crespo, A.; Castellanos-Estupinan, J.; Garcia-Sanchez, L. L.; Formoso-Prego, A.; Cores-Sanchez, A.

    2003-07-01

    In the present work high carbon ferrochrome (load ferrochrome) and slags are obtained, starting from the metallurgic reductive processing of refractory chromites. The obtaining of alloys and slags is studied using an experiment design based in the relationships among components. The chemical compositions of alloys and slags guarantee their application for the conformation of alloys loads and matrix fluxes amassed for the superficial filling by means of submerged arc welding (SAW). The melting-reduction process is carried out in an electric arc furnace. (Author) 16 refs.

  5. Ammonia at Blodgett Forest, Sierra Nevada, USA

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Marc L.; Littlejohn, David

    2007-11-06

    Ammonia is a reactive trace gas that is emitted in large quantities by animal agriculture and other sources in California, which subsequently forms aerosol particulate matter, potentially affecting visibility, climate, and human health. We performed initial measurements of NH{sub 3} at the Blodgett Forest Research Station (BFRS) during a two week study in June, 2006. The site is used for ongoing air quality research and is a relatively low-background site in the foothills of the Sierra Nevada. Measured NH{sub 3} mixing ratios were quite low (< 1 to {approx} 2 ppb), contrasting with typical conditions in many parts of the Central Valley. Eddy covariance measurements showed NH{sub 3} fluxes that scaled with measured NH{sub 3} mixing ratio and calculated aerodynamic deposition velocity, suggesting dry deposition is a significant loss mechanism for atmospheric NH{sub 3} at BFRS. A simple model of NH{sub 3} transport to the site supports the hypothesis that NH{sub 3} is transported from the Valley to BFRS, but deposits on vegetation during the summer. Further work is necessary to determine whether the results obtained in this study can be generalized to other seasons.

  6. Measurements of Ammonia at Blodgett Forest

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Marc L.; Littlejohn, David

    2007-04-01

    Ammonia is a reactive trace gas that is emitted in large quantities by animal agriculture and other sources in California, which subsequently forms aerosol particulate matter, potentially affecting visibility, climate, and human health. We performed initial measurements of NH{sub 3} at the Blodgett Forest Research Station (BFRS) during a 3 week study in June, 2006. The site is used for ongoing air quality research and is a relatively low-background site in the foothills of the Sierra Nevada. Measured NH{sub 3} mixing ratios were quite low (< 1 to {approx}2 ppb), contrasting with typical conditions in many parts of the Central Valley. Eddy covariance measurements showed NH{sub 3} fluxes that scaled with measured NH{sub 3} mixing ratio and calculated aerodynamic deposition velocity, suggesting dry deposition is a significant loss mechanism for atmospheric NH{sub 3} at BFRS. A simple model of NH{sub 3} transport to the site supports the hypothesis that NH{sub 3} is transported from the Valley to BFRS, but deposits on vegetation during the summer. Further work is necessary to determine whether the results obtained in this study can be generalized to other seasons.

  7. Radon flux measurement methodologies

    International Nuclear Information System (INIS)

    Nielson, K.K.; Rogers, V.C.

    1984-01-01

    Five methods for measuring radon fluxes are evaluated: the accumulator can, a small charcoal sampler, a large-area charcoal sampler, the ''Big Louie'' charcoal sampler, and the charcoal tent sampler. An experimental comparison of the five flux measurement techniques was also conducted. Excellent agreement was obtained between the measured radon fluxes and fluxes predicted from radium and emanation measurements

  8. Ammonia Induces Autophagy through Dopamine Receptor D3 and MTOR

    Science.gov (United States)

    Li, Zhiyuan; Ji, Xinmiao; Wang, Wenchao; Liu, Juanjuan; Liang, Xiaofei; Wu, Hong; Liu, Jing; Eggert, Ulrike S.; Liu, Qingsong

    2016-01-01

    Hyperammonemia is frequently seen in tumor microenvironments as well as in liver diseases where it can lead to severe brain damage or death. Ammonia induces autophagy, a mechanism that tumor cells may use to protect themselves from external stresses. However, how cells sense ammonia has been unclear. Here we show that culture medium alone containing Glutamine can generate milimolar of ammonia at 37 degrees in the absence of cells. In addition, we reveal that ammonia acts through the G protein-coupled receptor DRD3 (Dopamine receptor D3) to induce autophagy. At the same time, ammonia induces DRD3 degradation, which involves PIK3C3/VPS34-dependent pathways. Ammonia inhibits MTOR (mechanistic target of Rapamycin) activity and localization in cells, which is mediated by DRD3. Therefore, ammonia has dual roles in autophagy: one to induce autophagy through DRD3 and MTOR, the other to increase autophagosomal pH to inhibit autophagic flux. Our study not only adds a new sensing and output pathway for DRD3 that bridges ammonia sensing and autophagy induction, but also provides potential mechanisms for the clinical consequences of hyperammonemia in brain damage, neurodegenerative diseases and tumors. PMID:27077655

  9. Ammonia Release on ISS

    Science.gov (United States)

    Macatangay, Ariel

    2009-01-01

    Crew: Approximately 53% metabolic load Product of protein metabolism Limit production of ammonia by external regulation NOT possbile Payloads Potential source Scientific experiments Thorough safety review ensures sufficient levels of containment

  10. Reactor for removing ammonia

    Science.gov (United States)

    Luo, Weifang [Livermore, CA; Stewart, Kenneth D [Valley Springs, CA

    2009-11-17

    Disclosed is a device for removing trace amounts of ammonia from a stream of gas, particularly hydrogen gas, prepared by a reformation apparatus. The apparatus is used to prevent PEM "poisoning" in a fuel cell receiving the incoming hydrogen stream.

  11. Excretory nitrogen metabolism and defence against ammonia toxicity in air-breathing fishes.

    Science.gov (United States)

    Chew, S F; Ip, Y K

    2014-03-01

    With the development of air-breathing capabilities, some fishes can emerge from water, make excursions onto land or even burrow into mud during droughts. Air-breathing fishes have modified gill morphology and morphometry and accessory breathing organs, which would tend to reduce branchial ammonia excretion. As ammonia is toxic, air-breathing fishes, especially amphibious ones, are equipped with various strategies to ameliorate ammonia toxicity during emersion or ammonia exposure. These strategies can be categorized into (1) enhancement of ammonia excretion and reduction of ammonia entry, (2) conversion of ammonia to a less toxic product for accumulation and subsequent excretion, (3) reduction of ammonia production and avoidance of ammonia accumulation and (4) tolerance of ammonia at cellular and tissue levels. Active ammonia excretion, operating in conjunction with lowering of ambient pH and reduction in branchial and cutaneous NH₃ permeability, is theoretically the most effective strategy to maintain low internal ammonia concentrations. NH₃ volatilization involves the alkalization of certain epithelial surfaces and requires mechanisms to prevent NH₃ back flux. Urea synthesis is an energy-intensive process and hence uncommon among air-breathing teleosts. Aestivating African lungfishes detoxify ammonia to urea and the accumulated urea is excreted following arousal. Reduction in ammonia production is achieved in some air-breathing fishes through suppression of amino acid catabolism and proteolysis, or through partial amino acid catabolism leading to alanine formation. Others can slow down ammonia accumulation through increased glutamine synthesis in the liver and muscle. Yet, some others develop high tolerance of ammonia at cellular and tissue levels, including tissues in the brain. In summary, the responses of air-breathing fishes to ameliorate ammonia toxicity are many and varied, determined by the behaviour of the species and the nature of the environment in

  12. Titan's Ammonia Feature

    Science.gov (United States)

    Smythe, W.; Nelson, R.; Boryta, M.; Choukroun, M.

    2011-01-01

    NH3 has long been considered an important component in the formation and evolution of the outer planet satellites. NH3 is particularly important for Titan, since it may serve as the reservoir for atmospheric nitrogen. A brightening seen on Titan starting in 2004 may arise from a transient low-lying fog or surface coating of ammonia. The spectral shape suggests the ammonia is anhydrous, a molecule that hydrates quickly in the presence of water.

  13. Ammonia in the environment: From ancient times to the present

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, M.A.; Erisman, J.W.; Dentener, F.; Moller, D. [Centre for Ecology and Hydrology, Penicuik (United Kingdom). Edinburgh Research Station

    2008-12-15

    Recent research on atmospheric ammonia has made good progress in quantifying sources/sinks and environmental impacts. This paper reviews the achievements and places them in their historical context. It considers the role of ammonia in the development of agricultural science and air chemistry, showing how these arose out of foundations in 18th century chemistry and medieval alchemy, and then identifies the original environmental sources from which the ancients obtained ammonia. Ammonia is revealed as a compound of key human interest through the centuries, with a central role played by sal ammoniac in alchemy and the emergence of modern science. The review highlights how recent environmental research has emphasized volatilization sources of ammonia. Conversely, the historical records emphasize the role of high-temperature sources, including dung burning, coal burning, naturally burning coal seams and volcanoes. Present estimates of ammonia emissions from these sources are based on few measurements, which should be a future priority.

  14. Ammonia in the environment: from ancient times to the present.

    Science.gov (United States)

    Sutton, Mark A; Erisman, Jan Willem; Dentener, Frank; Möller, Detlev

    2008-12-01

    Recent research on atmospheric ammonia has made good progress in quantifying sources/sinks and environmental impacts. This paper reviews the achievements and places them in their historical context. It considers the role of ammonia in the development of agricultural science and air chemistry, showing how these arose out of foundations in 18th century chemistry and medieval alchemy, and then identifies the original environmental sources from which the ancients obtained ammonia. Ammonia is revealed as a compound of key human interest through the centuries, with a central role played by sal ammoniac in alchemy and the emergence of modern science. The review highlights how recent environmental research has emphasized volatilization sources of ammonia. Conversely, the historical records emphasize the role of high-temperature sources, including dung burning, coal burning, naturally burning coal seams and volcanoes. Present estimates of ammonia emissions from these sources are based on few measurements, which should be a future priority.

  15. Ammonia diffusion through Nalophan™ bags.

    Science.gov (United States)

    Sironi, Selena; Eusebio, Lidia; Dentoni, Licinia; Capelli, Laura; Del Rosso, Renato

    2014-01-01

    The aim of the work is to verify the diffusion rate of ammonia through the Nalophan™ film that constitutes the sampling bag, considering storage times ranging from 1 to 26 h. The ammonia decay over time was evaluated using gas-chromatography for the quantification of ammonia concentration inside the bag. The research assesses the roles of both of ammonia and water concentration gradients at the polymeric film interface on the diffusion process. The results show that both the ammonia concentration gradient and, in a less pronounced way, the water concentration gradient are the main 'engines' of ammonia diffusion. Double bags seem to represent a simple solution for preventing ammonia losses during storage. Another interesting result concerns the role of the bag surface on the ammonia diffusion rate: the higher the surface/volume (S/V) ratio, the higher the ammonia diffusion rate through the polymeric film.

  16. Radiation Chemistry in Ammonia-Water Ices

    Science.gov (United States)

    Loeffler, M. J.; Raut, U.; Baragiola, R. A.

    2010-01-01

    We studied the effects of 100 keV proton irradiation on films of ammonia-water mixtures between 20 and 120 K. Irradiation destroys ammonia, leading to the formation and trapping of H2, N2 NO, and N2O, the formation of cavities containing radiolytic gases, and ejection of molecules by sputtering. Using infrared spectroscopy, we show that at all temperatures the destruction of ammonia is substantial, but at higher temperatures (120 K), it is nearly complete (approximately 97% destroyed) after a fluence of 10(exp 16) ions per square centimeter. Using mass spectroscopy and microbalance gravimetry, we measure the sputtering yield of our sample and the main components of the sputtered flux. We find that the sputtering yield depends on fluence. At low temperatures, the yield is very low initially and increases quadratically with fluence, while at 120 K the yield is constant and higher initially. The increase in the sputtering yield with fluence is explained by the formation and trapping of the ammonia decay products, N2 and H2 which are seen to be ejected from the ice at all temperatures.

  17. Ammonia emissions of a rotational grazing system

    Science.gov (United States)

    Voglmeier, Karl; Häni, Christoph; Jocher, Markus; Ammann, Christof

    2017-04-01

    Intensive agricultural livestock production is the main source of air pollution by ammonia (NH3). Grazing is considered to reduce emissions significantly. However, ammonia emissions measurements on pastures are very rare and most emission models base their emissions factors for grazing on studies from the 1990s, which report a large emission range from 2.7% to 13.6% of the applied total ammonia nitrogen (TAN). We present first results of the Posieux pasture experiment in 2016 where NH3 concentration and fluxes were measured during the grazing season. The applied methods include an eddy covariance system with a two channel reactive nitrogen (Nr) converter measuring in parallel the sum of oxidized Nr species and the sum of the total Nr species. The difference of the two channels corresponds to the sum of reduced Nr species. Furthermore four MiniDOAS instruments for line integrated concentration measurements without an inlet system were used. The fluxes were estimated by applying a backward Lagrangian stochastic model (bLS) to the concentration difference of paired MiniDOAS up- and downwind of a sub-plot of the field. Monitoring of dung (visual survey) and urine patch locations (with soil electrical conductivity sensor) was carried out after each grazing rotation on selected sub-plots. It helped to compute statistics of the dung/urine patch distribution on the pasture. The experimental setup and the environmental conditions resulted in high temporal and spatial dynamics of NH3 concentrations and fluxes. The calculated fluxes were used to estimate the total net emission during the grazing period. Based on the average dung/urine patch distribution on the field an emission factor for the pasture was computed and compared to results from the literature. We discuss the applicability and limitations of the two measurement systems, reconsider the main emission drivers and explain differences in the results.

  18. Tritiated ammonia formation

    International Nuclear Information System (INIS)

    Heung, L.K.

    1995-01-01

    When nitrogen was selected as the glovebox atmosphere for the Replacement Tritium Facility (RTF) at the Savannah River Site (SRS), a concern was raised as to the possibility of tritiated ammonia formation in the gloveboxes. Experimental data were produced to study the tritiated ammonia formation rate in a tritium and nitrogen mixture. A rate equation that closely simulates the experimental data was developed. This rate equation can be used to calculate the formation of tritiated ammonia from different concentrations of tritium and nitrogen. The reaction of T 2 and N 2 to form NT 3 is a slow process, particularly when the tritium concentration is low. The reaction requires weeks or months to reach radiochemical equilibrium dependent on the concentrations of the reactants. 4 refs., 6 figs., 1 tab

  19. Respiratory ammonia output and blood ammonia concentration during incremental exercise

    NARCIS (Netherlands)

    Ament, W; Huizenga, [No Value; Kort, E; van der Mark, TW; Grevink, RG; Verkerke, GJ

    The aim of this study was to investigate whether the increase of ammonia concentration and lactate concentration in blood was accompanied by an increased expiration of ammonia during graded exercise. Eleven healthy subjects performed an incremental cycle ergometer test. Blood ammonia, blood lactate

  20. Liquid ammonia injury.

    Science.gov (United States)

    George, A; Bang, R L; Lari, A R; Gang, R K; Kanjoor, J R

    2000-06-01

    The toxic effects of a gas depend on the time of exposure, concentration and its chemical nature. Pressurized liquids and gases exert an additional cold thermal injury and this may complicate the clinical picture. A patient who had an accidental exposure to liquid ammonia over a prolonged period, manifesting in cutaneous, respiratory and ocular damage in addition to a severe cold thermal injury (frostbite) with a fatal outcome is presented. The patient had flaccid quadriparesis and episodes of bradycardia, which has not been reported previously. These manifestations raise the possibility of the systemic toxicity in patients with prolonged exposure to ammonia.

  1. Ammonia emissions in Europe

    DEFF Research Database (Denmark)

    Jacobsen, Brian H.

    2012-01-01

    The NEC (National Emission Ceiling) directive has set targets for the 2010 ammonia emissions from a number of European countries. The target will be reached by most EU-countries and the total emission for EU-27 has been reduced by 22% from 1990 to 2007. Denmark is one of the countries with the la......The NEC (National Emission Ceiling) directive has set targets for the 2010 ammonia emissions from a number of European countries. The target will be reached by most EU-countries and the total emission for EU-27 has been reduced by 22% from 1990 to 2007. Denmark is one of the countries...

  2. Effects of end-stage renal disease and dialysis modalities on blood ammonia level.

    Science.gov (United States)

    Vaziri, Nosratola D; Khazaeli, Mahyar; Nunes, Ane C F; Harley, Kevin T; Said, Hyder; Alipour, Omeed; Lau, Wei Ling; Pahl, Madeleine V

    2017-07-01

    Uremia results in a characteristic breath odor (uremic fetor) which is largely due to its high ammonia content. Earlier studies have shown a strong correlation between breath ammonia and blood urea levels and a 10-fold reduction in breath ammonia after hemodialysis in patients with chronic kidney disease. Potential sources of breath ammonia include: (i) local ammonia production from hydrolysis of urea in the oropharyngeal and respiratory tracts by bacterial flora, and (ii) release of circulating blood ammonia by the lungs. While the effects of uremia and hemodialysis on breath ammonia are well known their effects on blood ammonia are unknown and were explored here. Blood samples were obtained from 23 hemodialysis patients (immediately before and after dialysis), 14 peritoneal dialysis patients, and 10 healthy controls. Blood levels of ammonia, creatinine, urea, and electrolytes were measured. No significant difference was found in baseline blood ammonia between hemodialysis, peritoneal dialysis and control groups. Hemodialysis procedure led to a significant reduction in urea concentration (P ammonia level in 10 of the 23 patients studied. Change in blood ammonia pre- and post-hemodialysis correlated with change in serum bicarbonate levels (r = 0.61, P ammonia levels after dialysis, there was a strong correlation with drop in mean arterial pressure (r = 0.88, P ammonia compared to the patients who manifested a fall in blood ammonia (124 ± 8 vs. 136 ± 6 mmHg respectively, P = 0.27). Fall in blood urea following hemodialysis in ESRD patients was paradoxically accompanied by a modest rise in blood ammonia levels in 43% of the patients studied, contrasting prior reported effects of hemodialysis on breath ammonia. In this subgroup of patients, changes in blood ammonia during hemodialysis correlated with rise in blood bicarbonate and fall in mean arterial blood pressure. © 2016 International Society for Hemodialysis.

  3. The Ammonia-Soda Process.

    Science.gov (United States)

    Tingle, M.

    1979-01-01

    This article is a condensed version of a commentary written to accompany a set of slides which describes the ammonia-soda process used by the ammonia-soda plant at Northwich of the United Kingdom. (HM)

  4. Liberation of ammonia by cyanobacteria

    Energy Technology Data Exchange (ETDEWEB)

    Newton, J.W.

    1986-04-01

    Photoheterotrophic nitrogen-fixing cyanobacteria release ammonia when treated with methionine sulfoximine (MSX) to inhibit nitrogen incorporation into protein. This released ammonia can be derived from recently fixed nitrogen (nitrogen atmosphere) or endogenous reserves (argon atmosphere). Anaerobic ammonia release requires light and is stimulated by the photosystem II herbicides DCMU and Atrazine, regardless of the source of ammonia. As much as one quarter of the total cellular nitrogen can be released as ammonia by cyanbacteria treated with MSX and DCMU under argon in light. Chromatography of cell extracts indicates that virtually all cellular proteins are degraded. DCMU and Atrazine, at very low concentration, inhibit sustained uptake of the ammonia analog /sup 14/C methylamine. These data indicate that the herbicides interrupt ammonia uptake and retention by the cells, and support a role for photosystem II in ammonia metabolism.

  5. Spatial and temporal variations in ammonia emissions

    DEFF Research Database (Denmark)

    Skjøth, Carsten Ambelas; Geels, Camilla; Berge, H

    2011-01-01

    Deriving a parameterisation of ammonia emissions for use in chemistry-transport models (CTMs) is a complex problem as the emission varies locally as a result of local climate and local agricultural management. In current CTMs such factors are generally not taken into account. This paper demonstra......Deriving a parameterisation of ammonia emissions for use in chemistry-transport models (CTMs) is a complex problem as the emission varies locally as a result of local climate and local agricultural management. In current CTMs such factors are generally not taken into account. This paper...... demonstrates how local climate and local management can be accounted for in CTMs by applying a modular approach for deriving data as input to a dynamic ammonia emission model for Europe. Default data are obtained from information in the RAINS system, and it is demonstrated how this dynamic emission model based...

  6. Treatment of biomass to obtain ethanol

    Science.gov (United States)

    Dunson, Jr., James B.; Elander, Richard T [Evergreen, CO; Tucker, III, Melvin P.; Hennessey, Susan Marie [Avondale, PA

    2011-08-16

    Ethanol was produced using biocatalysts that are able to ferment sugars derived from treated biomass. Sugars were obtained by pretreating biomass under conditions of high solids and low ammonia concentration, followed by saccharification.

  7. Hydroaminomethylation in supercritical ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Martin, A.; Kant, M. [Leibniz-Institute for Catalysis, Berlin (Germany); Klein, H.; Jackstell, R.; Beller, M. [Leibniz-Institute for Catalysis, Rostock (Germany)

    2006-07-01

    Thermodynamic measurements were carried in the reaction system of hydroaminomethylation of olefins. Mixtures of ammonia, olefins, co-solvents, syngas and products such as nonylamine used as model and water were studied. In dependence on the reaction conditions and the mixtures selected opalescence points in a region from 92-290 bar and 120-172 C were found. (orig.)

  8. Effect of ammonia-generating diet on ovine serum and follicular fluid ammonia and urea levels, serum oestrogen and progesterone concentrations and granulosa cell functions.

    Science.gov (United States)

    Nandi, S; Mondal, S; Pal, D T; Gupta, P S P

    2016-04-01

    This study was undertaken to elucidate the effect of ammonia-generating diet on serum and follicular fluid ammonia and urea levels, serum oestrogen and progesterone concentrations and granulosa cell growth and secretion parameters in ewes (Ovis aries). Ewes were fed with 14% CP diet (control) or ammonia-generating diet or ammonia-generating diet plus soluble sugar. The serum and follicular fluid ammonia and urea level, serum oestrogen and progesterone levels and granulosa cell (obtained from ovaries of slaughtered ewes) growth parameters and secretory activities were estimated. Ammonia-generating diet (high-protein diet) increased the serum ammonia and urea concentration. Supplementation of soluble sugar significantly reduced the ammonia concentration in serum with comparable levels as in control group; however, the urea level in the same group was higher than that observed in control group. Supplementation of soluble sugar significantly reduced the follicular fluid ammonia concentration; however, the level was significantly higher compared to control group. Supplementation of soluble sugar brought down the follicular fluid urea level comparable to that observed in control group. Oestrogen and progesterone levels remained unchanged in ewes fed with different types of diet. Oestrogen and progesterone secretion were significantly lowered from granulosa cells recovered from ewes fed with high ammonia-generating diet. Low metabolic activity and high incidence of apoptosis were observed in granulosa cells obtained from ovaries of ewes fed with ammonia-generating diet. Journal of Animal Physiology and Animal Nutrition © 2015 Blackwell Verlag GmbH.

  9. Methods of ammonia removal in anaerobic digestion: a review.

    Science.gov (United States)

    Krakat, Niclas; Demirel, Burak; Anjum, Reshma; Dietz, Donna

    2017-10-01

    The anaerobic digestion of substrates with high ammonia content has always been a bottleneck in the methanisation process of biomasses. Since microbial communities in anaerobic digesters are sensitive to free ammonia at certain conditions, the digestion of nitrogen-rich substrates such as livestock wastes may result in inhibition/toxicity eventually leading to process failures, unless appropriate engineering precautions are taken. There are many different options reported in literature to remove ammonia from anaerobic digesters to achieve a safe and stable process so that along with high methane yields, a good quality of effluents can also be obtained. Conventional techniques to remove ammonia include physical/chemical methods, immobilization and adaptation of microorganisms, while novel methods include ultrasonication, microwave, hollow fiber membranes and microbial fuel cell applications. This paper discusses conventional and novel methods of ammonia removal from anaerobic digesters using nitrogen-rich substrates, with particular focus on recent literature available about this topic.

  10. Disinfection kinetics of pathogens in physicochemical sludge treated with ammonia.

    Science.gov (United States)

    Mendez, J M; Jimenez, B; Maya, C

    2004-01-01

    Ammonia is a disinfectant which can diffuse through the membrane of highly resistant structures like helminth ova. Thus, it can be considered an alternative disinfectant of wastewater sludge with high pathogenic content. In this study, the kinetic parameters of the Hom model were used to describe the inactivation with ammonia of faecal coliforms, Salmonella spp. and viable helminth ova. These were obtained in processes considering the addition of ammonia alone as well as for ammonia combined with an increase in temperature. The sludge was sampled from a municipal wastewater treatment plant using an APT (Advanced Primary Treatment) or CEP (Chemical Enhanced Primary) process. With 20% w/w of ammonia, 7 logs of faecal coliforms, 6 logs of Salmonella spp., and 83% of viable helminth ova were reduced in 2 hours contact time. To eliminate 100% of the helminth ova from samples having 88-132 ova/g TS it was needed to combine 20% of ammonia with 50 degrees C. The analysis of parameters k, n and m indicate higher resistance to inactivation of helminth ova compared to bacteria and a better performance of the ammonia process than lime stabilization to inactivate microorganisms. In addition, ammonia increased the agricultural value of the biosolids produced.

  11. Treatment of ammonia in liquid hospital waste using activated carbon

    Science.gov (United States)

    Riyanto, Hayati, Lena

    2017-12-01

    In this research study of the treatment of ammonia in liquid hospitals waste using activated carbon. This study aims to the effect of activated carbon weight and precipitation time to the treatment of ammonia in liquid hospitals waste. Hospital liquid waste has been taken from Jogja International Hospital (JIH) Yogyakarta, Indonesia. Hospital liquid waste 100 mL is mixed with activated carbon with the varied weight that is 15, 30 and 60 g. After added with activated carbon then stirred with a magnetic stirrer for 15 minutes and a precipitation time of 0.5, 1.0 and 2.0 hours. The next step is the filtrate analyzed ammonia concentrations before and after treatment using UV-Vis Spectrophotometer. The results showed that activated carbon can reduce ammonia concentration in hospital liquid waste. The amount of the active carbon and the time of stirring, the greater the ammonia concentration decreases in hospital liquid waste. The best condition for the decrease of the ammonia concentration was obtained with active carbon and precipitation time is 60 g and 1.0 hours, respectively with ammonia decrease of 95.93%. The conclusion is that activated carbon can reduce ammonia concentration in hospital liquid waste.

  12. The re-assimilation of ammonia produced by photorespiration and the nitrogen economy of C3 higher plants.

    Science.gov (United States)

    Keys, Alfred J

    2006-02-01

    Photorespiration involves the conversion of glycine to serine with the release of ammonia and CO(2). In C(3) terrestrial higher plants the flux through glycine and serine is so large that it results in the production of ammonia at a rate far exceeding that from reduction of new nitrogen entering the plant. The photorespiratory nitrogen cycle re-assimilates this ammonia using the enzymes glutamine synthetase and glutamine:2-oxoglutarateaminotransferase.

  13. Comparative study of ZnSe thin films deposited from modified chemical bath solutions with ammonia-containing and ammonia-free precursors

    International Nuclear Information System (INIS)

    Chen Liangyan; Zhang Daoli; Zhai Guangmei; Zhang Jianbing

    2010-01-01

    Ammonia is one of the complexing agents which are the most commonly used in the precursors of ZnSe thin films by chemical bath deposition, but its high volatility may be harmful to human beings and environments. In our experiments, ZnSe films were obtained from modified chemical solutions with ammonia-containing and ammonia-free precursors. X-ray diffraction, field-emission scanning electron microscope (FSEM), and absorption spectrum were applied to investigate the microstructure, morphology and optical properties of the samples obtained from both growth conditions, which were investigated in this work. The ammonia-free chemical bath deposited ZnSe films showed comparable properties with the ammonia-containing ones, indicating that ZnSe films from ammonia-free chemical solution may be preferred buffer layer in thin film solar cells with less environmental contamination.

  14. Ammonia Partitioning into the Condensed Phase in Winter Time Conditions

    Science.gov (United States)

    Green, J. R.; Bililign, S.; Fiddler, M. N.; Leen, J. B.; Holloway, J. S.; Fibiger, D. L.; McDuffie, E. E.; Thornton, J. A.; Brown, S. S.

    2015-12-01

    Secondary aerosol (SOA) formation has been linked to health problems and environmental damage in regions impacted by the emission of gaseous NH3 and SO2. SOA formation, (NH4)2SO4 and NH4NO3, in the presence of NO NO2, is favored under high relative humidity and low temperature and low temperature conditions. In the East and Mid Atlantic regions of the United States humidity is low in wintertime. Utilizing ambient concentration data of gaseous NO, NO2, SO2 and NH3 collected aboard a survey aircraft we examined the partitioning of gaseous NH3 towards aerosol products. The calculated mixing ratio of gaseous SO2/NH3 correlated with relative humidity will give an indication of the potential SOA formation when the mixing ratio of other reactants is small in the region of interest. The data obtained originates from a series of night and day survey flights on a C-130 aircraft that occurred from February 3 to March 13, 2015 over the Eastern coastal region of the United States extending from New York to Florida. NOx was obtained from the Airborne Ring-down Nitrogen Oxide Laser Detector (ARNOLD) instrument (NOAA) and Thermal Dissociation-Laser Induced Fluorescence (TD-LIF) (UC Berkley). SO2 measurements were done using the TECO 43C SO2 analyzer and for NH3 measurements the an Ammonia Analyzer - Trace (NH3) (Los Gatos Research). Estimates of aerosol dry deposition fluxes are presented.

  15. Ammonia in the environment: From ancient times to the present

    International Nuclear Information System (INIS)

    Sutton, Mark A.; Erisman, Jan Willem; Dentener, Frank; Moeller, Detlev

    2008-01-01

    Recent research on atmospheric ammonia has made good progress in quantifying sources/sinks and environmental impacts. This paper reviews the achievements and places them in their historical context. It considers the role of ammonia in the development of agricultural science and air chemistry, showing how these arose out of foundations in 18th century chemistry and medieval alchemy, and then identifies the original environmental sources from which the ancients obtained ammonia. Ammonia is revealed as a compound of key human interest through the centuries, with a central role played by sal ammoniac in alchemy and the emergence of modern science. The review highlights how recent environmental research has emphasized volatilization sources of ammonia. Conversely, the historical records emphasize the role of high-temperature sources, including dung burning, coal burning, naturally burning coal seams and volcanoes. Present estimates of ammonia emissions from these sources are based on few measurements, which should be a future priority. - Past ammonia applications reveal new emphases in biospheric transformations

  16. Potential for Ammonia Recapture by Farm Woodlands: Design and Application of a New Experimental Facility

    Directory of Open Access Journals (Sweden)

    Mark R. Theobald

    2001-01-01

    Full Text Available There has been increasing pressure on farmers in Europe to reduce the emissions of ammonia from their land. Due to the current financial climate in which farmers have to operate, it is important to identify ammonia control measures that can be adopted with minimum cost. The planting of trees around farmland and buildings has been identified as a potentially effective and low-cost measure to enhance ammonia recapture at a farm level and reduce long-range atmospheric transport. This work assesses experimentally what fraction of ammonia farm woodlands could potentially remove from the atmosphere. We constructed an experimental facility in southern Scotland to simulate a woodland shelterbelt planted in proximity to a small poultry unit. By measuring horizontal and vertical ammonia concentration profiles within the woodland, and comparing this to the concentration of an inert tracer (SF6 we estimate the depletion of ammonia due to dry deposition to the woodland canopy. Together with measurements of mean ammonia concentrations and throughfall fluxes of nitrogen, this information is used to provide a first estimate of the fraction of emitted ammonia that is recaptured by the woodland canopy. Analysis of these data give a lower limit of recapture of emitted ammonia, at the experimental facility, of 3%. By careful design of shelterbelt woodlands this figure could be significantly higher.

  17. SIRT5 regulation of ammonia-induced autophagy and mitophagy

    Science.gov (United States)

    Polletta, Lucia; Vernucci, Enza; Carnevale, Ilaria; Arcangeli, Tania; Rotili, Dante; Palmerio, Silvia; Steegborn, Clemens; Nowak, Theresa; Schutkowski, Mike; Pellegrini, Laura; Sansone, Luigi; Villanova, Lidia; Runci, Alessandra; Pucci, Bruna; Morgante, Emanuela; Fini, Massimo; Mai, Antonello; Russo, Matteo A; Tafani, Marco

    2015-01-01

    In liver the mitochondrial sirtuin, SIRT5, controls ammonia detoxification by regulating CPS1, the first enzyme of the urea cycle. However, while SIRT5 is ubiquitously expressed, urea cycle and CPS1 are only present in the liver and, to a minor extent, in the kidney. To address the possibility that SIRT5 is involved in ammonia production also in nonliver cells, clones of human breast cancer cell lines MDA-MB-231 and mouse myoblast C2C12, overexpressing or silenced for SIRT5 were produced. Our results show that ammonia production increased in SIRT5-silenced and decreased in SIRT5-overexpressing cells. We also obtained the same ammonia increase when using a new specific inhibitor of SIRT5 called MC3482. SIRT5 regulates ammonia production by controlling glutamine metabolism. In fact, in the mitochondria, glutamine is transformed in glutamate by the enzyme glutaminase, a reaction producing ammonia. We found that SIRT5 and glutaminase coimmunoprecipitated and that SIRT5 inhibition resulted in an increased succinylation of glutaminase. We next determined that autophagy and mitophagy were increased by ammonia by measuring autophagic proteolysis of long-lived proteins, increase of autophagy markers MAP1LC3B, GABARAP, and GABARAPL2, mitophagy markers BNIP3 and the PINK1-PARK2 system as well as mitochondrial morphology and dynamics. We observed that autophagy and mitophagy increased in SIRT5-silenced cells and in WT cells treated with MC3482 and decreased in SIRT5-overexpressing cells. Moreover, glutaminase inhibition or glutamine withdrawal completely prevented autophagy. In conclusion we propose that the role of SIRT5 in nonliver cells is to regulate ammonia production and ammonia-induced autophagy by regulating glutamine metabolism. PMID:25700560

  18. Field intercomparison of ammonia passive samplers: results and lessons learned.

    Science.gov (United States)

    Stephens, Amy; Leeson, Sarah; Jones, Matthew; van Dijk, Netty; Kentisbeer, John; Twigg, Marsailidh; Simmons, Ivan; Braban, Christine; Martin, Nick; Poskitt, Janet; Ferm, Martin; Seitler, Eva; Sacco, Paolo; Gates, Linda; Stolk, Ariën; Stoll, Jean-Marc; Tang, Sim

    2017-04-01

    Ammonia pollution contributes significantly to eutrophication and acidification of ecosystems with resultant losses of biodiversity and ecosystem changes. Monitoring of ambient ammonia over a wide spatial and long temporal scales is primarily done with low-cost diffusive samplers. Less frequently, surface flux measurements of ammonia can be made using passive samplers at plot scale. This paper will present a field intercomparison conducted within the MetNH3 project to assess the performance of passive samplers for ambient measurements of ammonia. Eight different designs of commercial passive samplers housed in shelters provided by the manufacturer/laboratory were exposed over an 8-week period at the Whim experimental field site in Scotland between August and October 2016. Whim Bog has a facility in place for controlled releases of ammonia (http://www.whimbog.ceh.ac.uk/). Automated conditional release from the line source occurs when the wind direction in the preceding minute is from the northeast (wind sector 180-215°) and wind speed is > 5 m s-1. The passive samplers were exposed at different distances from the release source (16, 32 and 60 m) and also at a background location. Most were exposed for 2 x 4-week long periods and some for 4 x 2-week long periods. At the 32 m position, an active denuder method, the CEH DELTA sampler and a continuous high temporal resolution wet chemistry ammonia instrument (AiRRmonia, Mechatronics, NL.) were also deployed alongside the passive samplers to provide reference measurements of ammonia. Results are presented within the context of the MetNH3 CATFAC controlled laboratory exposure assessments. The results are discussed in terms of typical deployments of passive samplers and quality control. Measurement for policy evidence for both local and regional studies using passive samplers are discussed.

  19. Marine, freshwater and aerially acclimated mangrove rivulus (Kryptolebias marmoratus) use different strategies for cutaneous ammonia excretion

    Science.gov (United States)

    Cooper, Christopher A.; Wilson, Jonathan M.

    2013-01-01

    Rhesus (Rh) glycoproteins are ammonia gas (NH3) channels known to be involved in ammonia transport in animals. Because of the different osmoregulatory and ionoregulatory challenges faced by teleost fishes in marine and freshwater (FW) environments, we hypothesized that ammonia excretion strategies would differ between environments. Also, we hypothesized that cutaneous NH3 volatilization in air-acclimated fish is facilitated by base secretion. To test these hypotheses, we used the skin of the euryhaline amphibious mangrove rivulus (Kryptolebias marmoratus). The skin excretes ammonia and expresses Rh glycoproteins. Serosal-to-mucosal cutaneous ammonia flux was saturable (0–16 mmol/l ammonia, Km of 6.42 mmol/l). In FW, ammonia excretion increased in response to low mucosal pH but decreased with pharmacological inhibition of Na+/H+ exchangers (NHE) and H+ ATPase. Conversely, in brackish water (BW), lowering the mucosal pH significantly decreased ammonia excretion. Inhibitors of NHE also decreased ammonia excretion in BW fish. Immunofluorescence microscopy demonstrated that both the Rh isoform, Rhcg1, and NHE3 proteins colocalized in Na+/K+ ATPase expressing mitochondrion-rich cells in the gills, kidney, and skin. We propose that the mechanisms of cutaneous ammonia excretion in FW K. marmoratus are consistent with the model for branchial ammonia excretion in FW teleost fish. NH4+ excretion appeared to play a stronger role in BW. NH4+ excretion in BW may be facilitated by apical NHE and/or diffuse through paracellular pathways. In aerially acclimated fish, inhibition of NHE and H+ ATPase, but not the Cl−/HCO3− exchanger, significantly affected cutaneous surface pH, suggesting that direct base excretion is not critical for NH3 volatilization. Overall, K. marmoratus use different strategies for excreting ammonia in three different environments, FW, BW, and air, and Rh glycoproteins and NHE are integral to all. PMID:23389109

  20. Renal Ammonia Metabolism and Transport

    Science.gov (United States)

    Weiner, I. David; Verlander, Jill W.

    2015-01-01

    Renal ammonia metabolism and transport mediates a central role in acid-base homeostasis. In contrast to most renal solutes, the majority of renal ammonia excretion derives from intrarenal production, not from glomerular filtration. Renal ammoniagenesis predominantly results from glutamine metabolism, which produces 2 NH4+ and 2 HCO3− for each glutamine metabolized. The proximal tubule is the primary site for ammoniagenesis, but there is evidence for ammoniagenesis by most renal epithelial cells. Ammonia produced in the kidney is either excreted into the urine or returned to the systemic circulation through the renal veins. Ammonia excreted in the urine promotes acid excretion; ammonia returned to the systemic circulation is metabolized in the liver in a HCO3−-consuming process, resulting in no net benefit to acid-base homeostasis. Highly regulated ammonia transport by renal epithelial cells determines the proportion of ammonia excreted in the urine versus returned to the systemic circulation. The traditional paradigm of ammonia transport involving passive NH3 diffusion, protonation in the lumen and NH4+ trapping due to an inability to cross plasma membranes is being replaced by the recognition of limited plasma membrane NH3 permeability in combination with the presence of specific NH3-transporting and NH4+-transporting proteins in specific renal epithelial cells. Ammonia production and transport are regulated by a variety of factors, including extracellular pH and K+, and by several hormones, such as mineralocorticoids, glucocorticoids and angiotensin II. This coordinated process of regulated ammonia production and transport is critical for the effective maintenance of acid-base homeostasis. PMID:23720285

  1. Hydrogen Production from Ammonia Using a Plasma Membrane Reactor

    Directory of Open Access Journals (Sweden)

    Shinji Kambara

    2016-06-01

    Full Text Available In this study, an efficient method for using pulsed plasma to produce hydrogen from ammonia was developed. An original pulsed plasma reactor with a hydrogen separation membrane was developed for efficient hydrogen production, and its hydrogen production performance was investigated. Hydrogen production in the plasma was affected by the applied voltage and flow rate of ammonia gas. The maximum hydrogen production flow rate of a typical plasma reactor was 8.7 L/h, whereas that of the plasma membrane reactor was 21.0 L/h. We found that ammonia recombination reactions in the plasma controlled hydrogen production in the plasma reactor. In the plasma membrane reactor, a significant increase in hydrogen production was obtained because ammonia recombination reactions were inhibited by the permeation of hydrogen radicals generated in the plasma through a palladium alloy membrane. The energy efficiency was 4.42 mol-H2/kWh depending on the discharge power.

  2. Review of Options for Ammonia/Ammonium Management

    Energy Technology Data Exchange (ETDEWEB)

    Nash, C. A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-05-06

    This report is a review of literature supporting practical ammonia/ammonium destruction processes. Melter research supporting Hanford Low Activity Waste (LAW) glass production has shown that significant amounts of ammonia will be in the melter offgas condensate. Further work with secondary waste forms indicates the potential need to remove the ammonia, perhaps by an oxidative process. This review finds likely practical chemical methods to oxidize ammonia in aqueous solution at moderate temperatures and atmospheric pressure, using easily obtained reagents. Leading candidates include nitrite oxidation to produce nitrogen gas, various peroxide oxidative processes, and air stripping. This work reviews many other processes and provides reasoning to not consider those processes further for this application.

  3. Experimental study of mixed additive of Ni(II) and piperazine on ammonia escape in CO2 capture using ammonia solution

    International Nuclear Information System (INIS)

    Ma, Shuangchen; Chen, Gongda; Zhu, Sijie; Wen, Jiaqi; Gao, Ran; Ma, Lan; Chai, Jin

    2016-01-01

    Highlights: • Compound additive was used to obtain high CO 2 absorption efficiency and low NH 3 escape. • Both organic material and metal ion were applied as compound additive. • Influences of additives on CO 2 absorption and NH 3 escape were investigated. • Possible mechanism and products were analyzed by XRD and UV–visible spectrophotometer. - Abstract: In order to obtain high CO 2 absorption efficiency and low ammonia escape rate, mixed additives of piperazine and Ni(II) were used as absorbent in bubbling reactor. The effects of mixed additive on CO 2 absorption efficiency and ammonia escape rate were investigated; the performances of mixed additive in removal process were compared with that of pure ammonia solution. The proposed mechanism was analyzed by XRD and UV–visible spectrophotometer. The mixed additive has well effect on CO 2 absorption efficiency and ammonia escape reduction. The CO 2 absorption efficiency was 72% when 2 wt% ammonia solution mixed with 0.025 mol/L piperazine and 0.05 mol/L Ni(II), higher than that achieved by 3 wt% ammonia solution without additive, and the amount of ammonia loss was nearly 1/3 compared with 3 wt% pure ammonia solution. This paper provided one feasible method which is beneficial to the balance between CO 2 absorption and ammonia escape in CO 2 capture process.

  4. CADDIS Volume 2. Sources, Stressors and Responses: Ammonia

    Science.gov (United States)

    Introduction to the ammonia module, when to list ammonia as a candidate cause, ways to measure ammonia, simple and detailed conceptual diagrams for ammonia, literature reviews and references for the ammonia module.

  5. Anhydrous Ammonia Frost on Titan

    Science.gov (United States)

    Smythe, W. D.; Nelson, R.; Boryta, M. D.

    2009-12-01

    Ammonia has been suggested as a probable source for sustaining Titan's thick nitrogen-dominated atmosphere. Ammonia is believed to be important to maintaining nitrogen in Titan's atmosphere. Ammonia is seen in clouds in the atmospheres of Jupiter and Saturn, but has yet to be detected on any of the satellites. This may be because all forms of NH3 are unstable in the ambient conditions of the satellites surfaces or that its spectral features are altered by other components of the surface, and have not been identified. It has recently been demonstrated[1] that brightening occurs in Titan’s atmosphere that is transient on the time-scale of months. The spectral shape of the brightening is more consistent with that of the transient apparition of a pure ammonia frost than of an ammonia monohydrate or ammonia dihydrate frost. However, the phase behavior of the ammonia water system has peritectics at compositions of 1:1 and 1:2. These hydrate forms would be expected to dominate if the frost, or the reservoir from which the frost was derived had any water present. Physical mechanisms for producing measurable quanitities of anhydrous ammonia can include chemical dehydration or dehydration of the vapor phase - but it is challenging to store significant quantities of the anhydrous material because of the phase behavior in the solid state. [1] Nelson, R.M., et al. Saturn’s Titan: Surface Change, Ammonia, and Implications for Atmospheric and Tectonic Activity., Icarus, 199, pp. 429-441, 2009 This work was performed at JPL under contract to NASA

  6. Ammonia emissions from deciduous forest after leaf fall

    DEFF Research Database (Denmark)

    Hansen, Kristina; Sørensen, Lise Lotte; Hertel, Ole

    2013-01-01

    The understanding of biochemical feedback mechanisms in the climate system is lacking knowledge in relation to bi-directional ammonia (NH3) exchange between natural ecosystems and the atmosphere. We therefore study the atmospheric NH3 fluxes during a 25-day period during autumn 2010 (21 October...... leaf fall, the magnitude and temporal structure of the measured NH3 emission fluxes could be adequately reproduced with the bi-directional resistance model; it suggested the forest ground layer (soil and litter) to be the main contributing component to the NH3 emissions. The modelled concentration from...

  7. Ammonia-based quantum computer

    International Nuclear Information System (INIS)

    Ferguson, Andrew J.; Cain, Paul A.; Williams, David A.; Briggs, G. Andrew D.

    2002-01-01

    We propose a scheme for quantum computation using two eigenstates of ammonia or similar molecules. Individual ammonia molecules are confined inside fullerenes and used as two-level qubit systems. Interaction between these ammonia qubits takes place via the electric dipole moments, and in particular we show how a controlled-NOT gate could be implemented. After computation the qubit is measured with a single-electron electrometer sensitive enough to differentiate between the dipole moments of different states. We also discuss a possible implementation based on a quantum cellular automaton

  8. The importance of the ammonia purification process in ammonia-water absorption systems

    International Nuclear Information System (INIS)

    Fernandez-Seara, Jose; Sieres, Jaime

    2006-01-01

    Practical experience in working with ammonia-water absorption systems shows that the ammonia purification process is a crucial issue in order to obtain an efficient and reliable system. In this paper, the detrimental effects of the residual water content in the vapour refrigerant are described and quantified based on the system design variables that determine the effectiveness of the purification process. The study has been performed considering a single stage system with a distillation column with complete condensation. The ammonia purification effectiveness of the column is analysed in terms of the efficiencies in the stripping and rectifying sections and the reflux ratio. By varying the efficiencies from 0 to 1, systems with neither the rectifying nor stripping section, with either the rectifying or stripping section, or with both sections can be considered. The impact of the ammonia purification process on the absorption system performance is studied based on the column efficiencies and reflux ratio; and its effects on refrigerant concentration, system COP, system pressures and main system mass flow rates and concentrations are analysed. When the highest efficiency rectifying sections are used a combination of generation temperature and reflux ratio which leads to optimum COP values is found. The analysis covers different operating conditions with air and water cooled systems from refrigeration to air conditioning applications by changing the evaporation temperature. The importance of rectification in each kind of application is evaluated

  9. Wastewater Treatment with Ammonia Recovery System

    OpenAIRE

    M. Örvös; T. Balázs; K. F. Both

    2008-01-01

    From environmental aspect purification of ammonia containing wastewater is expected. High efficiency ammonia desorption can be done from the water by air on proper temperature. After the desorption process, ammonia can be recovered and used in another technology. The calculation method described below give some methods to find either the minimum column height or ammonia rich solution of the effluent.

  10. Anaerobic digestion of swine manure: Inhibition by ammonia

    DEFF Research Database (Denmark)

    Hansen, Kaare Hvid; Angelidaki, Irini; Ahring, Birgitte Kiær

    1998-01-01

    A stable anaerobic degradation of swine manure with ammonia concentration of 6 g-N/litre was obtained in continuously stirred tank reactors with a hydraulic retention time of 15 days, at Four different temperatures. Methane yields of 188, 141, 67 and 22 ml-CH4/g-VS were obtained at 37, 45, 55...

  11. Study of ammonia synthesis over uranium catalysts

    International Nuclear Information System (INIS)

    Spitsyn, V.I.; Erofeev, B.V.; Mikhajlenko, I.E.; Gorelkin, I.I.; Ivanov, L.S.

    1980-01-01

    The effect of induced radiactivity and chemical composition of uranium catalysts on their catalytic activity in the ammonia synthesis reaction has been studied. The catalyst samples comprise pieces of metal uranium and chip irradiated in nuclear reactor by the 4.3x10 16 n/cm 2 integral flux of slow neutrons. Studies of catalytic activity was carried out at 1 atm and 340-510 deg C when stoichiometric nitrogen-hydrogen mixture passed through the following installation. At different temperatures uranium nitrides of different composition are shown to be formed. Uranium nitrides with the composition close to UN 2 are the samples with the highest catalYtic activity. The reduction of catalytic activity of uranium catalysts with the increased temperature of their formation above 400 deg C is explained by low catalytic activity of forming UNsub(1.7) in comparison with UN 2 . Catalytic properties of irradiated and nonirradiated samples do not differ from one another

  12. Coupling Solid Oxide Electrolyser (SOE) and ammonia production plant

    International Nuclear Information System (INIS)

    Cinti, Giovanni; Frattini, Domenico; Jannelli, Elio; Desideri, Umberto; Bidini, Gianni

    2017-01-01

    Highlights: • An innovative NH 3 production plant was designed. • CO 2 emissions and energy consumption are studied in three different designs. • High temperature electrolysis allows to achieve high efficiency and heat recovery. • The coupling permits storage of electricity into a liquid carbon free chemical. - Abstract: Ammonia is one of the most produced chemicals worldwide and is currently synthesized using nitrogen separated from air and hydrogen from natural gas reforming with consequent high consumption of fossil fuel and high emission of CO 2 . A renewable path for ammonia production is desirable considering the potential development of ammonia as energy carrier. This study reports design and analysis of an innovative system for the production of green ammonia using electricity from renewable energy sources. This concept couples Solid Oxide Electrolysis (SOE), for the production of hydrogen, with an improved Haber Bosch Reactor (HBR), for ammonia synthesis. An air separator is also introduced to supply pure nitrogen. SOE operates with extremely high efficiency recovering high temperature heat from the Haber-Bosch reactor. Aspen was used to develop a model to study the performance of the plant. Both the SOE and the HBR operate at 650 °C. Ammonia production with zero emission of CO 2 can be obtained with a reduction of 40% of power input compared to equivalent plants.

  13. A highly flexible polymerization technique to prepare fluorescent nanospheres for trace ammonia detection

    International Nuclear Information System (INIS)

    Waich, K.; Sandholzer, M.; Mayr, T.; Slugovc, C.; Klimant, I.

    2010-01-01

    The preparation of pH-sensitive nanospheres by emulsion polymerization for the detection of trace levels of ammonia is described. A fluorescent, polymerizable xanthene dye was copolymerized with styrene, crosslinkers and further copolymers aimed at enhancing the sensitivity to obtain materials for sensing of ammonia. A half-seeded technique was used to obtain stable emulsions of the monomers which were cured to obtain nanospheres with covalently attached active components. The nanospheres were embedded in a silicon matrix and the sensor films obtained were investigated regarding their response to ammonia at concentrations between 25 and 1,000 ppb. Sensors containing polystyrene nanospheres crosslinked with divinylbenzene showed the best performance in ammonia measurements exhibiting detection limits (LODs) of less than 25 ppb ammonia.

  14. Analysis of ammonia separation from purge gases in microporous hollow fiber membrane contactors.

    Science.gov (United States)

    Karami, M R; Keshavarz, P; Khorram, M; Mehdipour, M

    2013-09-15

    In this study, a mathematical model was developed to analyze the separation of ammonia from the purge gas of ammonia plants using microporous hollow fiber membrane contactors. A numerical procedure was proposed to solve the simultaneous linear and non linear partial differential equations in the liquid, membrane and gas phases for non-wetted or partially wetted conditions. An equation of state was applied in the model instead of Henry's law because of high solubility of ammonia in water. The experimental data of CO₂-water system in the literature was used to validate the model due to the lack of data for ammonia-water system. The model showed that the membrane contactor can separate ammonia very effectively and with recoveries higher than 99%. SEM images demonstrated that ammonia caused some micro-cracks on the surfaces of polypropylene fibers, which could be an indication of partial wetting of membrane in long term applications. However, the model results revealed that the membrane wetting did not have significant effect on the absorption of ammonia because of very high solubility of ammonia in water. It was also found that the effect of gas velocity on the absorption flux was much more than the effect of liquid velocity. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Ammonia Synthesis at Low Pressure.

    Science.gov (United States)

    Cussler, Edward; McCormick, Alon; Reese, Michael; Malmali, Mahdi

    2017-08-23

    Ammonia can be synthesized at low pressure by the use of an ammonia selective absorbent. The process can be driven with wind energy, available locally in areas requiring ammonia for synthetic fertilizer. Such wind energy is often called "stranded," because it is only available far from population centers where it can be directly used. In the proposed low pressure process, nitrogen is made from air using pressure swing absorption, and hydrogen is produced by electrolysis of water. While these gases can react at approximately 400 °C in the presence of a promoted conventional catalyst, the conversion is often limited by the reverse reaction, which makes this reaction only feasible at high pressures. This limitation can be removed by absorption on an ammine-like calcium or magnesium chloride. Such alkaline metal halides can effectively remove ammonia, thus suppressing the equilibrium constraints of the reaction. In the proposed absorption-enhanced ammonia synthesis process, the rate of reaction may then be controlled not by the chemical kinetics nor the absorption rates, but by the rate of the recycle of unreacted gases. The results compare favorably with ammonia made from a conventional small scale Haber-Bosch process.

  16. Effect of competing ions and causticization on the ammonia adsorption by a novel poly ligand exchanger (PLE) ammonia adsorption reagent.

    Science.gov (United States)

    Chen, Quanzhou; Zhou, Kanggen; Hu, Yuanjuan; Liu, Fang; Wang, Aihe

    2017-03-01

    In this paper, a poly ligand exchanger, Cu(II)-loaded chelating resin named ammonia adsorption reagent (AMAR), bearing the functional group of weak iminodiacetate acid, was prepared to efficiently remove ammonia from solutions. Batch adsorption equilibrium experiments were conducted under a range of conditions. The effects of pH on the removal of ammonia by AMAR were investigated at 25 °C. The copper loaded on the resin forms a complex with NH 3 in solution under alkaline condition. The effect of alkaline dosage (AD) on the ammonia adsorption was investigated. The maximum breakthrough bed volumes were obtained when the AD was set as 0.75 mmol OH - /mL. The higher AD did not guarantee the better ammonia removal efficiency due to the forming of Cu(OH) 2 precipitate between OH - in solutions and Cu(II) on the resin. The effect of competing ions on the adsorption breakthrough curve of virgin AMAR and causticized AMAR was also investigated. The results demonstrated that the existence of competing ions had a negative impact on the adsorption capacity for both virgin AMAR and causticized AMAR. After causticization, the AMAR was more resistant to the competing ions comparing with virgin AMAR. The bivalent Ca 2+ affects the ammonia adsorption more than does the monovalent Na + .

  17. Mass transfer of ammonia escape and CO2 absorption in CO2 capture using ammonia solution in bubbling reactor

    International Nuclear Information System (INIS)

    Ma, Shuangchen; Chen, Gongda; Zhu, Sijie; Han, Tingting; Yu, Weijing

    2016-01-01

    Highlights: • Mass transfer coefficient models of ammonia escape were built. • Influences of temperature, inlet CO 2 and ammonia concentration were studied. • Mass transfer coefficients of ammonia escape and CO 2 absorption were obtained. • Studies can provide the basic data as a reference guideline for process application. - Abstract: The mass transfer of CO 2 capture using ammonia solution in the bubbling reactor was studied; according to double film theory, the mass transfer coefficient models and interface area model were built. Through our experiments, the overall volumetric mass transfer coefficients were obtained, while the interface areas in unit volume were estimated. The volumetric mass transfer coefficients of ammonia escaping during the experiment were 1.39 × 10 −5 –4.34 × 10 −5 mol/(m 3 s Pa), and the volumetric mass transfer coefficients of CO 2 absorption were 2.86 × 10 −5 –17.9 × 10 −5 mol/(m 3 s Pa). The estimated interface area of unit volume in the bubbling reactor ranged from 75.19 to 256.41 m 2 /m 3 , making the bubbling reactor a viable choice to obtain higher mass transfer performance than the packed tower or spraying tower.

  18. Measurement and Modelling of Ammonia Emissions at Waste Treatment Lagoon-Atmospheric Interface

    International Nuclear Information System (INIS)

    Aneja, Viney P.; Malik, Brahm P.; Tong Quansong; Kang Daiwen; Overton, John H.

    2001-01-01

    Global emissions of ammonia are approximately 75 Tg N/yr (1 Tg =10 12 g). The major global source is excreta from domestic animals (∼ 32 Tg N -1 yr -1 ). Waste storage and treatment lagoons are used to treat the excreta of hogs in North Carolina (NC). Proteins and nitrogen rich compounds in the lagoon are converted to ammonia, through a series of biological and chemical transformations. The process of ammonia emission has been investigated using two different model approaches: (1) CoupledMass Transfer with Chemical Reaction Model (Model I), and (2)Mass Transport without Chemical Reaction Model (Model II). A sensitivity analysis is performed with the models, and the model results are compared with ammonia emission experiments at a swine waste storage and treatment lagoon in NC using a dynamic emission flux chamber. Results of model predictions of emission flux indicate an exponential increase in ammonia flux with increasing lagoon temperature and pH, a linear increase with increasing lagoon total ammoniacal nitrogen (TAN), and a secondary degree increase with the increasing wind speed. In addition, the fluxes predicted by Model I are consistently larger than fluxes predicted by Model II. Experimental values of flux agreed well with model predictions, with the experimental values lying in different positions between the two model predictions under different physical and chemical conditions. Further, when compared to diurnal and seasonal experimental flux values, Model I corroborates the results in calm meteorological conditions (windspeed U10 = 1.5 m s -1 ). However, the observed results are better predicted by Model II during unstable conditions, when wind speeds are higher than 2.0 m s -1 and physical transfer process functions dominate

  19. Measurement and Modelling of Ammonia Emissions at Waste Treatment Lagoon-Atmospheric Interface

    Energy Technology Data Exchange (ETDEWEB)

    Aneja, Viney P.; Malik, Brahm P.; Tong Quansong; Kang Daiwen [North Carolina State University, Department of Marine, Earth, and Atmospheric Sciences (United States); Overton, John H

    2001-09-15

    Global emissions of ammonia are approximately 75 Tg N/yr (1 Tg =10{sup 12}g). The major global source is excreta from domestic animals ({approx} 32 Tg N {sup -1}yr{sup -1}). Waste storage and treatment lagoons are used to treat the excreta of hogs in North Carolina (NC). Proteins and nitrogen rich compounds in the lagoon are converted to ammonia, through a series of biological and chemical transformations. The process of ammonia emission has been investigated using two different model approaches: (1) CoupledMass Transfer with Chemical Reaction Model (Model I), and (2)Mass Transport without Chemical Reaction Model (Model II). A sensitivity analysis is performed with the models, and the model results are compared with ammonia emission experiments at a swine waste storage and treatment lagoon in NC using a dynamic emission flux chamber. Results of model predictions of emission flux indicate an exponential increase in ammonia flux with increasing lagoon temperature and pH, a linear increase with increasing lagoon total ammoniacal nitrogen (TAN), and a secondary degree increase with the increasing wind speed. In addition, the fluxes predicted by Model I are consistently larger than fluxes predicted by Model II. Experimental values of flux agreed well with model predictions, with the experimental values lying in different positions between the two model predictions under different physical and chemical conditions. Further, when compared to diurnal and seasonal experimental flux values, Model I corroborates the results in calm meteorological conditions (windspeed U10 = 1.5 m s{sup -1}). However, the observed results are better predicted by Model II during unstable conditions, when wind speeds are higher than 2.0 m s{sup -1} and physical transfer process functions dominate.

  20. Ammonia lowering reverses sarcopenia of cirrhosis by restoring skeletal muscle proteostasis.

    Science.gov (United States)

    Kumar, Avinash; Davuluri, Gangarao; Silva, Rafaella Nascimento E; Engelen, Marielle P K J; Ten Have, Gabrie A M; Prayson, Richard; Deutz, Nicolaas E P; Dasarathy, Srinivasan

    2017-06-01

    Sarcopenia or skeletal muscle loss is a frequent, potentially reversible complication in cirrhosis that adversely affects clinical outcomes. Hyperammonemia is a consistent abnormality in cirrhosis that results in impaired skeletal muscle protein synthesis and breakdown (proteostasis). Despite the availability of effective ammonia-lowering therapies, whether lowering ammonia restores proteostasis and increases muscle mass is unknown. Myotube diameter, protein synthesis, and molecular responses in C2C12 murine myotubes to withdrawal of ammonium acetate following 24-hour exposure to 10 mM ammonium acetate were complemented by in vivo studies in the hyperammonemic portacaval anastomosis rat and sham-operated, pair-fed Sprague-Dawley rats treated with ammonia-lowering therapy by l-ornithine l-aspartate and rifaximin orally for 4 weeks. We observed reduced myotube diameter, impaired protein synthesis, and increased autophagy flux in response to hyperammonemia, which were partially reversed following 24-hour and 48-hour withdrawal of ammonium acetate. Consistently, 4 weeks of ammonia-lowering therapy resulted in significant lowering of blood and skeletal muscle ammonia, increase in lean body mass, improved grip strength, higher skeletal muscle mass and diameter, and an increase in type 2 fibers in treated compared to untreated portacaval anastomosis rats. The increased skeletal muscle myostatin expression, reduced mammalian target of rapamycin complex 1 function, and hyperammonemic stress response including autophagy markers normally found in portacaval anastomosis rats were reversed by treatment with ammonia-lowering therapy. Despite significant improvement, molecular and functional readouts were not completely reversed by ammonia-lowering measures. Ammonia-lowering therapy results in improvement in skeletal muscle phenotype and function and molecular perturbations of hyperammonemia; these preclinical studies complement previous studies on ammonia-induced skeletal muscle

  1. Treatment of biomass to obtain a target chemical

    Science.gov (United States)

    Dunson, Jr., James B.; Tucker, III, Melvin P.; Elander, Richard T.; Hennessey, Susan Marie

    2010-08-24

    Target chemicals were produced using biocatalysts that are able to ferment sugars derived from treated biomass. Sugars were obtained by pretreating biomass under conditions of high solids and low ammonia concentration, followed by saccharification.

  2. Improving ammonia emissions in air quality modelling for France

    Science.gov (United States)

    Hamaoui-Laguel, Lynda; Meleux, Frédérik; Beekmann, Matthias; Bessagnet, Bertrand; Génermont, Sophie; Cellier, Pierre; Létinois, Laurent

    2014-08-01

    We have implemented a new module to improve the representation of ammonia emissions from agricultural activities in France with the objective to evaluate the impact of such emissions on the formation of particulate matter modelled with the air quality model CHIMERE. A novel method has been set up for the part of ammonia emissions originating from mineral fertilizer spreading. They are calculated using the one dimensional 1D mechanistic model “VOLT'AIR” which has been coupled with data on agricultural practices, meteorology and soil properties obtained at high spatial resolution (cantonal level). These emissions display high spatiotemporal variations depending on soil pH, rates and dates of fertilization and meteorological variables, especially soil temperature. The emissions from other agricultural sources (animal housing, manure storage and organic manure spreading) are calculated using the national spatialised inventory (INS) recently developed in France. The comparison of the total ammonia emissions estimated with the new approach VOLT'AIR_INS with the standard emissions provided by EMEP (European Monitoring and Evaluation Programme) used currently in the CHIMERE model shows significant differences in the spatiotemporal distributions. The implementation of new ammonia emissions in the CHIMERE model has a limited impact on ammonium nitrate aerosol concentrations which only increase at most by 10% on the average for the considered spring period but this impact can be more significant for specific pollution episodes. The comparison of modelled PM10 (particulate matter with aerodynamic diameter smaller than 10 μm) and ammonium nitrate aerosol with observations shows that the use of the new ammonia emission method slightly improves the spatiotemporal correlation in certain regions and reduces the negative bias on average by 1 μg m-3. The formation of ammonium nitrate aerosol depends not only on ammonia concentrations but also on nitric acid availability, which

  3. 15N-enrichments of ammonia and glutamine in blood after infusion of 15N-ammonia in chickens fed low or high protein diet

    International Nuclear Information System (INIS)

    Karasawa, Yutaka; Koh, Katsuki

    1985-01-01

    In this experment, the blood ammonia and glutamine amide came from infused ammonia were determined when N-15 labeled ammonium acetate was intraportally infused into the chickens fed 5 or 20 % protein diet. The data obtained indicated that the infused ammonia was taken into blood glutamine amide, and also accumulated in blood as it is, in both dietary groups. 10 to 12 months old White Leghorn male birds were used. The experimental diet was fed once a day for 5 days to the birds weighting about 1.2 kg by 35 g per kg body weight. The experimental diet was consumed within 40 min in all cases. Cardiac and portal catheterization were performed for blood collection and ammonia infusion, respectively. After finishing the infusion, blood samples were taken to analyze the ammonia and glutamine contents and their N-15 enrichment. Statistical difference was not observed in the appearance of N-15 in ammonia and glutamine amide between two dietary groups. The N-15 enrichment in blood ammonia and the amide of plasma glutamine, and the calculated exogenous nitrogen in the ammonia and glutamine amide tended to be more in the 5 % protein diet group than the other. (Kako, I.)

  4. Phenol recovery with liquid ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Heilman

    1943-08-03

    This report covers the results of a phenol recovery plant at Ludwigshafen which had recently suffered a severe explosion. From a Gelsenberg hydrogenation middle oil with 18 percent phenol, an 86 to 96 percent phenol fraction was recovered. Because the occurring neutral oil was phenol-free and because with the process a phenol loss was impossible, it was assumed that the yield was quantitative. With regard to the working process, the middle oil was fed into the upper section of a column four feet high, in which liquid ammonia from below climbed upward. The ammonia thereby absorbed the phenol quantitatively, and the ammonium phenolate solution absorbed a certain amount of neutral oil. The loaded ammonia went over the top of the column while at the foot of the column the phenol-free neutral oil collected and was drawn off. The ammonium phenolate solution was then washed with light gasoline in a second column. For this, the ammonia was fed into the upper, the light gasoline into the lower part of the column. The light gasoline absorbed almost quantitatively the neutral oil which was molecularly or actually colloidally dissolved in the ammonium phenolate solution, and even a small amount of the phenol and ammonia. Thickening in concentration, the light gasoline was fed into a storage tank where it was freed of its dissolved components by atmospheric distillation and recycled into the process. The ammonium phenolate solution which before the gasoline wash left behind a vaporization residue with about 40 percent phenol afterwards produced a raw phenol of 86 to 96 percent pure phenol. Because of technical difficulties, the concentration of the washed ammonium phenolate solution could not be determined. It was gathered at the bottom of the second column and fed into a storage tank where the phenol was freed by pressure distillation. The ammonia was then recycled into the process.

  5. Ammonia abatement by slurry acidification

    DEFF Research Database (Denmark)

    Petersen, Søren O.; Hutchings, Nicholas J.; Hafner, Sasha D.

    2016-01-01

    Livestock production systems can be major sources of trace gases including ammonia (NH3), the greenhouse gases methane (CH4) and nitrous oxide (N2O), and odorous compounds such as hydrogen sulphide (H2S). Short-term campaigns have indicated that acidification of livestock slurry during in...... sections with 30-32 pigs with or without daily adjustment of slurry pH to below 6. Ammonia losses from reference sections with untreated slurry were between 9.5 and 12.4% of N excreted, and from sections with acidified slurry between 3.1 and 6.2%. Acidification reduced total emissions of NH3 by 66 and 71...

  6. Catalytic Organometallic Reactions of Ammonia

    Science.gov (United States)

    Klinkenberg, Jessica L.

    2012-01-01

    Until recently, ammonia had rarely succumbed to catalytic transformations with homogeneous catalysts, and the development of such reactions that are selective for the formation of single products under mild conditions has encountered numerous challenges. However, recently developed catalysts have allowed several classes of reactions to create products with nitrogen-containing functional groups from ammonia. These reactions include hydroaminomethylation, reductive amination, alkylation, allylic substitution, hydroamination, and cross-coupling. This Minireview describes examples of these processes and the factors that control catalyst activity and selectivity. PMID:20857466

  7. Ammonia synthesis at low temperatures

    DEFF Research Database (Denmark)

    Rod, Thomas Holm; Logadottir, Ashildur; Nørskov, Jens Kehlet

    2000-01-01

    Density functional theory (DFT) calculations of reaction paths and energies for the industrial and the biological catalytic ammonia synthesis processes are compared. The industrial catalyst is modeled by a ruthenium surface, while the active part of the enzyme is modeled by a MoFe6S9 complex...... have been carried out to evaluate its feasibility. The calculations suggest that it might be possible to catalytically produce ammonia from molecular nitrogen at low temperatures and pressures, in particular if energy is fed into the process electrochemically. (C) 2000 American Institute of Physics....

  8. Ammonia-water Rankine cycle

    International Nuclear Information System (INIS)

    Bo Hanliang; Ma Changwen; Wu Shaorong

    1997-01-01

    On characteristics of heating source and cooling source in nuclear heating reactor cooperation, the authors advance a new kind of power cycle in which a multicomponent mixture as the work fluid, ammonia-water Rankine cycle, describe its running principle, and compare it with steam Rankine cycle in the same situation. The result is that: the new kind of power cycle, ammonia-water Rankine cycle has higher electricity efficiency; it suits for the situation of heating source and cooling source which offered by nuclear heating reactor cooperation. For low temperature heating source, it maybe has a widely application

  9. The influence of nitrate and ammonia nitrogen on the photosynthetic ...

    African Journals Online (AJOL)

    A study has been made on the influence of nitrate and ammonia nitrogen on the carbon dioxide compensation point (T), carboxylating enzymes and growth of highveld grasses found at the primary, secondary and climax successional stages. The results obtained are discussed in relation to the influence of nitrogen on ...

  10. RESULTS OF INITIAL AMMONIA OXIDATION TESTING

    Energy Technology Data Exchange (ETDEWEB)

    Nash, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Fowley, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-12-30

    This memo presents an experimental survey of aqueous phase chemical processes to remove aqueous ammonia from waste process streams. Ammonia is generated in both the current Hanford waste flowsheet and in future waste processing. Much ammonia will be generated in the Low Activity Waste (LAW) melters.i Testing with simulants in glass melters at Catholic University has demonstrated the significant ammonia production.ii The primary reaction there is the reducing action of sugar on nitrate in the melter cold cap. Ammonia has been found to be a problem in secondary waste stabilization. Ammonia vapors are noxious and destruction of ammonia could reduce hazards to waste treatment process personnel. It is easily evolved especially when ammonia-bearing solutions are adjusted to high pH.

  11. Energy efficient ammonia heat pump. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Madsen, Claus; Pijnenburg, B.; Schumann Grindorf, H. [Danish Technological Institute, Aarhus (Denmark); Christensen, Rolf [Alfa Laval, Lund (Sweden); Rasmussen, Bjarne D. [Grundfos, Bjerringbro (Denmark); Gram, S.; Fredborg Jakobsen, D. [Svedan Industri Koeleanlaeg, Greve (Denmark)

    2013-09-15

    The report describes the development of a highly effective ammonia heat pump. Heat pumps play an increasingly important role in the search for more effective use of energy in our society. Highly efficient heat pumps can contribute to reduced energy consumption and improved economy of the systems which they are a part of. An ammonia heat pump with high pressure reciprocating compressor and a novel split condenser was developed to prove potential for efficiency optimization. The split of the condenser in two parts can be utilized to obtain smaller temperature approaches and, thereby, improved heat pump efficiency at an equal heat exchanger area, when compared to the traditional solution with separate condenser and de-superheater. The split condenser design can also be exploited for heating a significant share of the total heating capacity to a temperature far above the condensing temperature. Furthermore, the prototype heat pump was equipped with a plate type evaporator combined with a U-turn separator with a minimum liquid height and a liquid pump with the purpose of creating optimum liquid circulation ratio for the highest possible heat transfer coefficients at the lowest possible pressure drop. The test results successfully confirmed the highest possible efficiency; a COP of 4.3 was obtained when heating water from 40 deg. C to 80 deg. C while operating with evaporating/condensing temperatures of +20 deg C/+73 deg C. (Author)

  12. Recycling of Ammonia Wastewater During Vanadium Extraction from Shale

    Science.gov (United States)

    Shi, Qihua; Zhang, Yimin; Liu, Tao; Huang, Jing

    2018-03-01

    In the vanadium metallurgical industry, massive amounts of ammonia hydroxide or ammonia salt are added during the precipitation process to obtain V2O5; therefore, wastewater containing a high level of NH4 + is generated, which poses a serious threat to environmental and hydrologic safety. In this article, a novel process was developed to recycle ammonia wastewater based on a combination of ammonia wastewater leaching and crystallization during vanadium extraction from shale. The effects of the NH4 + concentration, temperature, time and liquid-to-solid ratio on the leaching efficiencies of vanadium, aluminum and potassium were investigated, and the results showed that 93.2% of vanadium, 86.3% of aluminum and 96.8% of potassium can be leached from sulfation-roasted shale. Subsequently, 80.6% of NH4 + was separated from the leaching solution via cooling crystallization. Vanadium was recovered via a combined method of solvent extraction, precipitation and calcination. Therefore, ammonia wastewater was successfully recycled during vanadium extraction from shale.

  13. AMMONIA INHIBITION IN THERMOPHILIC ANAEROBIC DIGESTION OF DAIRY CATTLE MANURE

    Directory of Open Access Journals (Sweden)

    S. Sutaryo

    2015-04-01

    Full Text Available This study investigated the effect of five different concentrations of total ammonia nitrogen (TANand free ammonia (FA on the methane yield and digester performance under thermophilic conditions(50°C. Five identical continuously fed digesters were used. The experiment was run for four timeshydraulic retention time (HRT. Data were statitically analysed using the data Analysis Tool Packavailable with the Microsoft Excel program. Different ammonia levels were obtained by pulsing urea toobtain the target level of TAN and FA, and to subsequently maintaining the concentration of ammonialevels by daily urea additions. The result showed a strong negative correlation between both TAN andFA concentrations and methane yield. The methane yield was reduced by 24, 30, 52 and 66% indigesters that had TAN levels of 2.9, 3.6, 4.4 and 5.1 g/L, respectively, corresponding to 0.7, 1.1,1.5 and1.8 g/L FA. Total volatile fatty acid and especially isovaleric and isobutyric acid concentrations wereelevated during ammonia inhibition. Concentration of TAN in the biogas digester exceeding 3 g/Lindicating that very often the full biogas potential is not achieved due to ammonia inhibition and thatlonger HRT should be used to compensate or a lower process temperature should be chosen.

  14. Clinical utility of breath ammonia for evaluation of ammonia physiology in healthy and cirrhotic adults

    OpenAIRE

    Spacek, Lisa A; Mudalel, Matthew; Tittel, Frank; Risby, Terence H; Solga, Steven F

    2015-01-01

    Blood ammonia is routinely used in clinical settings to assess systemic ammonia in hepatic encephalopathy and urea cycle disorders. Despite its drawbacks, blood measurement is often used as a comparator in breath studies because it is a standard clinical test. We sought to evaluate sources of measurement error and potential clinical utility of breath ammonia compared to blood ammonia.

  15. Determination of ammonia in ear-lobe capillary blood is an alternative to arterial blood ammonia

    NARCIS (Netherlands)

    Huizenga, J. R.; Gips, C. H.; Conn, H. O.; Jansen, P. L.

    1995-01-01

    Blood ammonia determination is a laboratory test to diagnose hepatic encephalopathy. Arterial blood is superior to peripheral venous blood ammonia because of ammonia metabolism in muscle. We have compared capillary with arterial whole blood ammonia as capillary sampling is an attractive alternative.

  16. DETERMINATION OF AMMONIA IN EAR-LOBE CAPILLARY BLOOD IS AN ALTERNATIVE TO ARTERIAL BLOOD AMMONIA

    NARCIS (Netherlands)

    HUIZENGA, [No Value; GIPS, CH; CONN, HO; JANSEN, PLM

    1995-01-01

    Blood ammonia determination is a laboratory test to diagnose hepatic encephalopathy. Arterial blood is superior to peripheral venous blood ammonia because of ammonia metabolism in muscle. We have compared capillary with arterial whole blood ammonia as capillary sampling is an attractive alternative.

  17. 46 CFR 154.1760 - Liquid ammonia.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Liquid ammonia. 154.1760 Section 154.1760 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR....1760 Liquid ammonia. The master shall ensure that no person sprays liquid ammonia into a cargo tank...

  18. 27 CFR 21.96 - Ammonia, aqueous.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Ammonia, aqueous. 21.96 Section 21.96 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT... Ammonia, aqueous. (a) Alkalinity. Strongly alkaline to litmus. (b) Ammonia content. 27 to 30 percent by...

  19. Preparation and characterization of polysulfone/zeolite mixed matrix membranes for removal of low-concentration ammonia from aquaculture wastewater.

    Science.gov (United States)

    Moradihamedani, Pourya; Abdullah, Abdul Halim

    2018-01-01

    Removal of low-concentration ammonia (1-10 ppm) from aquaculture wastewater was investigated via polysulfone (PSf)/zeolite mixed matrix membrane. PSf/zeolite mixed matrix membranes with different weight ratios (90/10, 80/20, 70/30 and 60/40 wt.%) were prepared and characterized. Results indicate that PSf/zeolite (80/20) was the most efficient membrane for removal of low-concentration ammonia. The ammonia elimination by PSf/zeolite (80/20) from aqueous solution for 10, 7, 5, 3 and 1 ppm of ammonia was 100%, 99%, 98.8%, 96% and 95% respectively. The recorded results revealed that pure water flux declined in higher loading of zeolite in the membrane matrix due to surface pore blockage caused by zeolite particles. On the other hand, ammonia elimination from water was decreased in higher contents of zeolite because of formation of cavities and macrovoids in the membrane substructure.

  20. Ammonia concentrations in canine whole blood, EDTA-anticoagulated whole blood, and plasma measured by use of a point-of-care ammonia meter.

    Science.gov (United States)

    Odunayo, Adesola; Tobias, Karen M; Okafor, Chika C; Flatland, Bente

    2017-11-01

    OBJECTIVE To investigate the use of canine whole blood (WB) for measurement of ammonia concentration by use of a point-of-care ammonia meter and to compare results of measuring ammonia concentrations in WB, EDTA-anticoagulated WB, and plasma. ANIMALS 40 client-owned dogs. PROCEDURES A blood sample (2 mL) was obtained from each dog. One drop of WB was immediately applied to a test strip for evaluation with an ammonia meter. The remainder of the blood sample was placed in an EDTA-containing tube, and 1 drop of EDTA-anticoagulated WB was applied to a test strip. The remaining EDTA-anticoagulated WB sample was centrifuged, and the plasma was harvested and placed on ice. One drop of plasma was applied to a test strip; the remainder of the plasma sample was transported on ice and used for ammonia measurement with a reference laboratory instrument. All samples were tested within 1 hour after sample collection. Results were evaluated to detect significant differences in ammonia concentration. RESULTS Ammonia concentrations did not differ significantly between WB and EDTA-anticoagulated WB and between plasma samples measured with the meter and reference laboratory instrument. However, median ammonia concentration was significantly higher in plasma than in WB or EDTA-anti-coagulated WB. CONCLUSIONS AND CLINICAL RELEVANCE Anticoagulant-free WB was a valid sample for measurement by use of the ammonia meter. Plasma samples had higher ammonia concentrations than did WB samples. Results for each sample type should be interpreted by use of specimen- and method-specific reference intervals.

  1. Hydrogen production using ammonia borane

    Science.gov (United States)

    Hamilton, Charles W; Baker, R. Thomas; Semelsberger, Troy A; Shrestha, Roshan P

    2013-12-24

    Hydrogen ("H.sub.2") is produced when ammonia borane reacts with a catalyst complex of the formula L.sub.nM-X wherein M is a base metal such as iron, X is an anionic nitrogen- or phosphorus-based ligand or hydride, and L is a neutral ancillary ligand that is a neutral monodentate or polydentate ligand.

  2. Reducing ammonia emissions in Europe

    DEFF Research Database (Denmark)

    Jacobsen, Brian H.

    2011-01-01

    The NEC directive has set targets for the 2010 ammonia emissions from a number of European countries. The target will be reached by most EU-countries and the total emission for EU-27 has been reduced by 22% from 1990 to 2007. Denmark is one of the countries with the largest reductions since 1990...

  3. by thiocyanates in liquid ammonia

    African Journals Online (AJOL)

    ABSTRACT. Infrared and Raman spectroscopy techniques have been used to study the ionic interactions of strontium(II) and barium(II) with thiocyanate ion in liquid ammonia. A number of bands were observed in both ν(CN) and ν(CS) regions of infrared and Raman spectra and these were assigned to 1:1 contact ion pair, ...

  4. Haber Process for Ammonia Synthesis

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 16; Issue 12. Haber Process for Ammonia Synthesis. Jayant M Modak. Volume 16 Issue 12 December 2011 pp 1159-1167. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/016/12/1159-1167. Keywords.

  5. Haber Process for Ammonia Synthesis

    Indian Academy of Sciences (India)

    Before synthetic nitrogen fixation, wastes and manures of various types or their decomposition products, and ammonium sulfate, which is a by-product from the coking of coal, were the primary sources of agricultural nitrogen. Chilean saltpetre, saltpetre from hu- man and animal urine, and later ammonia recovered from coke.

  6. Use of flux welding slag of the Mn-O-SiO{sub 2} system for the obtaining of a new alloyed agglomerated flux; Empleo de escorias de soldadura del sistema MnO-SiO{sub 2} para la obtencion de un nuevo fundente aglomerado aleado

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, A.; Quintana, R.; Garcia, L. L.; Perdomo, L.; Jimenez, G.; Gomez, C. R.; Alguacil, F. J.; Cores, A.

    2005-07-01

    This paper deals with the use of welding slags of the MnO-SiO{sub 2} system fluxes, coming from the recovering by means of the submerged arc welding in the manufacturing of agglomerated fluxes for surfacing with the same propose. the composition of the matrix is studied by means of an experimental design in a restricted area of the Mc Lean Anderson kind, the technological behaviour of the different mixtures is checked, and the results of the best types that have alloy charges included are analysed by a characterization of the weld. (Author) 20 refs.

  7. Transcriptional Response of the Archaeal Ammonia Oxidizer Nitrosopumilus maritimus to Low and Environmentally Relevant Ammonia Concentrations

    OpenAIRE

    Nakagawa, Tatsunori; Stahl, David A.

    2013-01-01

    The ability of chemoautotrophic ammonia-oxidizing archaea to compete for ammonia among marine microorganisms at low ambient concentrations has been in part attributed to their extremely high affinity for ammonia, but as yet there is no mechanistic understanding of supporting metabolism. We examined transcription of selected genes for anabolic functions (CO2 fixation, ammonia transport, and cell wall synthesis) and a central catabolic function (ammonia oxidation) in the thaumarchaeon Nitrosopu...

  8. Transcriptional Response of the Archaeal Ammonia Oxidizer Nitrosopumilus maritimus to Low and Environmentally Relevant Ammonia Concentrations

    Science.gov (United States)

    Stahl, David A.

    2013-01-01

    The ability of chemoautotrophic ammonia-oxidizing archaea to compete for ammonia among marine microorganisms at low ambient concentrations has been in part attributed to their extremely high affinity for ammonia, but as yet there is no mechanistic understanding of supporting metabolism. We examined transcription of selected genes for anabolic functions (CO2 fixation, ammonia transport, and cell wall synthesis) and a central catabolic function (ammonia oxidation) in the thaumarchaeon Nitrosopumilus maritimus SCM1 growing at two ammonia concentrations, as measured by combined ammonia and ammonium, one well above the Km for ammonia oxidation (∼500 μM) and the other well below the Km (ammonia-replete to ammonia-limiting conditions. Transcript levels for ammonia oxidation, CO2 fixation, and one of the ammonia transport genes were approximately the same at high and low ammonia availability. Transcripts for all analyzed genes decreased with time in the complete absence of ammonia, but with various rates of decay. The new steady-state mRNA levels established are presumably more reflective of the natural physiological state of ammonia-oxidizing archaea and offer a reference for interpreting message abundance patterns in the natural environment. PMID:23995944

  9. Coal gas desulfurization by the ammonia method. Odsiarczanie gazu koksowniczego metoda amoniakalna

    Energy Technology Data Exchange (ETDEWEB)

    Gwiner, H. (Instytut Chemii Przerobki Wegla (Poland))

    1988-01-01

    Reviews principles of gas desulfurization by the ammonia method and the various processes used: the methods of Still, Koppers, DIAMOX, DESULF, Zyklopur (of Kohletechnik). Further processing of NH{sub 3} and H{sub 2}S obtained in the ammonia process is considered, i.e. production of ammonium sulphates, sulfuric acid, ammonia and elemental sulfur. Advantages of the ammonia method are described: no foreign chemicals used, low cost, no need for gas heating or open cooling towers and a high degree of desulfurization. Hydrogen sulfide content as low as 0.7-1 g/m{sup 3} is gained. Additional cleaning by gaseous ammonia or soda lye permits the hydrogen sulfide content to be reduced down to 0.2-0.5 g/m{sup 3}. 65 refs.

  10. Indoor concentrations of ammonia and the potential contribution of humans to atmospheric budgets

    Science.gov (United States)

    Atkins, D. H. F.; Lee, David S.

    Simple passive diffusion tube samplers were used for the determination of ammonia concentrations in homes. The gas was collected by molecular diffusion on sulphuric-acid-impregnated glass-fibre discs and subsequently determined spectrophotometrically. In a survey of 10 homes, ammonia levels were found to average 39, 37 and 32 μg m -3 (NH 3 as N), respectively, in kietchens living rooms and bedrooms. The maximum concentration found was 85 μg m -3 in a kitchen and a minimum of 13 μg m -3 in a kitchen and a living room. These values were obtained with sampling periods of at least 1 week. The relative constancy of ammonia levels throughout the houses surveyed may be explained on the basis that the occupants themselves are the main source of the gas. The potential human contribution to atmospheric ammonia is discussed along with its implications for ammonia budgets in the atmosphere.

  11. [Spectroscopic study on the high voltage fast pulsed discharge of nitrogen, ammonia or their mixture].

    Science.gov (United States)

    Liu, Z P; Wang, P N; Yang, W D; Zheng, J B; Li, F M

    2001-10-01

    The emission spectra from the pulsed discharge plasma of nitrogen, ammonia or their mixture were measured. In the discharge of pure nitrogen gas, as the pressure increased, the discharge volume decreased and more dissociation of nitrogen molecules occurred due to the higher energy density. In the discharge of ammonia, N,N+ and NH+ were observed, but no NH2 and NH3 were detected, indicating that ammonia, which has the lower dissociation and ionization energies as compared to nitrogen, was highly dissociated. The discharge of the mixture of N2 and NH3 was also studied. The dependence of the dissociation of nitrogen on the ratio of nitrogen to ammonia was investigated by emission spectra. The optimal ratio for nitrogen dissociation was obtained. The advantage of using the mixture of nitrogen and ammonia in the synthesis of nitrides was discussed.

  12. Preparation of a Ammonia-Treated Lac Dye and Structure Elucidation of Its Main Component.

    Science.gov (United States)

    Nishizaki, Yuzo; Ishizuki, Kyoko; Akiyama, Hiroshi; Tada, Atsuko; Sugimoto, Naoki; Sato, Kyoko

    2016-01-01

    Lac dye and cochineal extract contain laccaic acids and carminic acid as the main pigments, respectively. Both laccaic acids and carminic acid are anthraquinone derivatives. 4-Aminocarminic acid (acid-stable carmine), an illegal colorant, has been detected in several processed foods. 4-Aminocarminic acid is obtained by heating cochineal extract (carminic acid) in ammonia solution. We attempted to prepare ammonia-treated lac dye and to identify the structures of the main pigment components. Ammonia-treated lac dye showed acid stability similar to that of 4-aminocarminic acid. The structures of the main pigments in ammonia-treated lac dye were analyzed using LC/MS. One of the main pigments was isolated and identified as 4-aminolaccaic acid C using various NMR techniques, including 2D-INADEQUATE. These results indicated that ammonia-treatment of lac dye results in the generation of 4-aminolaccaic acids.

  13. Purification of ammonia-containing trap waters from atomic power plant by ozone treatment

    International Nuclear Information System (INIS)

    Grachok, M.A.; Prokudina, S.A.; Shulyat'ev, M.I.

    1990-01-01

    The aim of research was to study the process of ozonation of ammonia-containing trap waters from the Kursk Atomic Power Plant both on the model solutions and on real ones. Different factors (pH of the medium, temperature, concentration of the initial substances) have been studied for their effect on ozonation of aqueous ammonia solutions, model solutions of trap waters from the Kursk Atomic Power Plant as well as ammonia-containing trap waters and liquid radioactive wastes delivered to special water treatment at the Kursk Atomic Power Plant. It is shown that in all the cases the highest rate of ammonia oxidation by ozone is observed in the alkaline medium (pH 1.4-11.0) and at 55 deg C. The obtained results have shown that a method of ozonation followed by evaporation of water to be purified can be used to treat ammonia-containing waters from atomic power plant

  14. Accuracy of cuticular resistance parameterizations in ammonia dry deposition models

    Science.gov (United States)

    Schrader, Frederik; Brümmer, Christian; Richter, Undine; Fléchard, Chris; Wichink Kruit, Roy; Erisman, Jan Willem

    2016-04-01

    Accurate representation of total reactive nitrogen (Nr) exchange between ecosystems and the atmosphere is a crucial part of modern air quality models. However, bi-directional exchange of ammonia (NH3), the dominant Nr species in agricultural landscapes, still poses a major source of uncertainty in these models, where especially the treatment of non-stomatal pathways (e.g. exchange with wet leaf surfaces or the ground layer) can be challenging. While complex dynamic leaf surface chemistry models have been shown to successfully reproduce measured ammonia fluxes on the field scale, computational restraints and the lack of necessary input data have so far limited their application in larger scale simulations. A variety of different approaches to modelling dry deposition to leaf surfaces with simplified steady-state parameterizations have therefore arisen in the recent literature. We present a performance assessment of selected cuticular resistance parameterizations by comparing them with ammonia deposition measurements by means of eddy covariance (EC) and the aerodynamic gradient method (AGM) at a number of semi-natural and grassland sites in Europe. First results indicate that using a state-of-the-art uni-directional approach tends to overestimate and using a bi-directional cuticular compensation point approach tends to underestimate cuticular resistance in some cases, consequently leading to systematic errors in the resulting flux estimates. Using the uni-directional model, situations where low ratios of total atmospheric acids to NH3 concentration occur lead to fairly high minimum cuticular resistances, limiting predicted downward fluxes in conditions usually favouring deposition. On the other hand, the bi-directional model used here features a seasonal cycle of external leaf surface emission potentials that can lead to comparably low effective resistance estimates under warm and wet conditions, when in practice an expected increase in the compensation point due to

  15. Simultaneous and multi-point measurement of ammonia emanating from human skin surface for the estimation of whole body dermal emission rate.

    Science.gov (United States)

    Furukawa, Shota; Sekine, Yoshika; Kimura, Keita; Umezawa, Kazuo; Asai, Satomi; Miyachi, Hayato

    2017-05-15

    Ammonia is one of the members of odor gases and a possible source of odor in indoor environment. However, little has been known on the actual emission rate of ammonia from the human skin surface. Then, this study aimed to estimate the whole-body dermal emission rate of ammonia by simultaneous and multi-point measurement of emission fluxes of ammonia employing a passive flux sampler - ion chromatography system. Firstly, the emission fluxes of ammonia were non-invasively measured for ten volunteers at 13 sampling positions set in 13 anatomical regions classified by Kurazumi et al. The measured emission fluxes were then converted to partial emission rates using the surface body areas estimated by weights and heights of volunteers and partial rates of 13 body regions. Subsequent summation of the partial emission rates provided the whole body dermal emission rate of ammonia. The results ranged from 2.9 to 12mgh -1 with an average of 5.9±3.2mgh -1 per person for the ten healthy young volunteers. The values were much greater than those from human breath, and thus the dermal emission of ammonia was found more significant odor source than the breath exhalation in indoor environment. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Data Acquisition and Flux Calculations

    DEFF Research Database (Denmark)

    Rebmann, C.; Kolle, O; Heinesch, B

    2012-01-01

    In this chapter, the basic theory and the procedures used to obtain turbulent fluxes of energy, mass, and momentum with the eddy covariance technique will be detailed. This includes a description of data acquisition, pretreatment of high-frequency data and flux calculation.......In this chapter, the basic theory and the procedures used to obtain turbulent fluxes of energy, mass, and momentum with the eddy covariance technique will be detailed. This includes a description of data acquisition, pretreatment of high-frequency data and flux calculation....

  17. Ammonia toxicity: from head to toe?

    Science.gov (United States)

    Dasarathy, Srinivasan; Mookerjee, Rajeshwar P; Rackayova, Veronika; Rangroo Thrane, Vinita; Vairappan, Balasubramaniyan; Ott, Peter; Rose, Christopher F

    2017-04-01

    Ammonia is diffused and transported across all plasma membranes. This entails that hyperammonemia leads to an increase in ammonia in all organs and tissues. It is known that the toxic ramifications of ammonia primarily touch the brain and cause neurological impairment. However, the deleterious effects of ammonia are not specific to the brain, as the direct effect of increased ammonia (change in pH, membrane potential, metabolism) can occur in any type of cell. Therefore, in the setting of chronic liver disease where multi-organ dysfunction is common, the role of ammonia, only as neurotoxin, is challenged. This review provides insights and evidence that increased ammonia can disturb many organ and cell types and hence lead to dysfunction.

  18. Ammonia for hydrogen storage: challenges and opportunities

    DEFF Research Database (Denmark)

    Klerke, Asbjørn; Christensen, Claus H.; Nørskov, Jens Kehlet

    2008-01-01

    The possibility of using ammonia as a hydrogen carrier is discussed. Compared to other hydrogen storage materials, ammonia has the advantages of a high hydrogen density, a well-developed technology for synthesis and distribution, and easy catalytic decomposition. Compared to hydrocarbons...... and alcohols, it has the advantage that there is no CO2 emission at the end user. The drawbacks are mainly the toxicity of liquid ammonia and the problems related to trace amounts of ammonia in the hydrogen after decomposition. Storage of ammonia in metal ammine salts is discussed, and it is shown...... that this maintains the high volumetric hydrogen density while alleviating the problems of handling the ammonia. Some of the remaining challenges for research in ammonia as a hydrogen carrier are outlined....

  19. Control of ammonia air pollution through the management of thermal processes in cowsheds.

    Science.gov (United States)

    Bleizgys, Rolandas; Bagdoniene, Indre

    2016-10-15

    Experimental researches performed in manufacturing cowsheds have demonstrated a variation of ammonia concentration and the factors influencing this most during different periods of the year. The process of ammonia evaporation from manure is influenced by many varying and interrelated factors with temperature and the intensity of air ventilation being the most critical ones. The influence of these factors on the process of ammonia evaporation was established by laboratory researches. An increase in temperature results in an exponential increase in ammonia emission, whereas the dependence of the emission on the air velocity is best expressed by a second degree polynomial. The results obtained may be used as a forecast of the ammonia emissions from cowsheds during different periods of the year. Intensive ventilation is required for the removal of excess moisture from the housing, and this limits the possibilities to reduce ammonia emissions by controlling the intensity of ventilation. A reduction in the amount of ventilation is only recommended if the air quality indices meet the requirements applied to the housing. Better opportunities to reduce ammonia emissions are provided through management of the thermal processes in a cowshed. If the average annual air temperature (11.3°C) is reduced by one degree in a cubicle housing cowshed, the ammonia emissions will decrease by 10%. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. A STUDY OF THE EFFECTS OF POST-COMBUSTION AMMONIA INJECTION ON FLY ASH QUALITY: CHARACTERIZATION OF AMMONIA RELEASE FROM CONCRETE AND MORTARS CONTAINING FLY ASH AS A POZZOLANIC ADMIXTURE

    Energy Technology Data Exchange (ETDEWEB)

    Robert F. Rathbone; Thomas L. Robl

    2001-04-11

    Work completed in this reporting period focused on finalization of the Work and Management Plan, sample acquisition and analysis, evaluation of ammonia measurement methods, and measurement of ammonia loss from mortar. All fly ash samples have been acquired and analyzed for chemical composition and particle fineness. Three non-ammoniated fly ash samples were obtained from power plants that do not inject ammonia for NOx or particulate control, while three ammoniated fly ashes originate from plants that inject ammonia into the flue gas. The fly ash sources were selected based on their marketability as concrete admixtures and ammonia content. Coarse and fine aggregates for mortar and concrete testing have also been secured and have been thoroughly characterized using ASTM methods. Methodologies for the measurement of ammonia in the gaseous and aqueous phase have been carefully considered in the context of their suitability for use in this project. These include ammonia detection tubes, carbon impregnated with sulfuric acid (CISA) tubes, titration, and electrochemical methods. It was concluded that each of these methods is potentially useful for different aspects of the project, depending on the phase and concentration of ammonia to be measured. Preparation of fly ash-containing mortars both with and without ammonia indicated that the ammonia has no significant influence on compressive strength. Finally, measurement of ammonia loss from mortar has begun and the results of several of these experiments are included herein. It has been found that, under the laboratory curing conditions devised, ammonia release from mortar occurs at a relatively rapid rate in the first 24 hours, proceeded by a much slower, essentially linear rate. Furthermore, at the end of the three-week experiments, it was calculated that greater than 80% of the initial ammonia concentration remained within the mortar.

  1. Kinetics and thermodynamics of Si(111) surface nitridation in ammonia

    Science.gov (United States)

    Mansurov, Vladimir G.; Malin, Timur V.; Galitsyn, Yurij G.; Shklyaev, Alexander A.; Zhuravlev, Konstantin S.

    2016-05-01

    Kinetics and thermodynamics of Si(111) surface nitridation under an ammonia flux at different substrate temperatures are investigated by reflection high-energy electron diffraction. Two different stages of the nitridation process were revealed. The initial stage is the fast (within few seconds) formation of ordered two-dimensional SiN phase, occuring due to the topmost active surface Si atom (Sisurf) interaction with ammonia molecules. It is followed by the late stage consisting in the slow (within few minutes) amorphous Si3N4 phase formation as a result of the interaction of Si atoms in the lattice site (Siinc) with chemisorbed ammonia molecules. It was found that the ordered SiN phase formation rate decreases, as the temperature increases. The kinetic model of the initial stage was developed, in which the ordered SiN phase formation is the two-dimensional phase transition in the lattice gas with SiN cells. The enthalpy of the active surface Si atom generation on the clean Si(111) surface was estimated to be about 1.5 eV. In contrast, the amorphous Si3N4 phase formation is the normal (thermally activated) chemical process with the first-order kinetics, whose activation energy and pre-exponential factor are 2.4 eV and 108 1/s, respectively.

  2. A low-temperature process for the denitration of Hanford single-shell tank, nitrate-based waste utilizing the nitrate to ammonia and ceramic (NAC) or nitrate to ammonia and glass (NAG) process: Phase 2 report

    International Nuclear Information System (INIS)

    Mattus, A.J.; Walker, J.F. Jr.; Youngblood, E.L.; Farr, L.L.; Lee, D.D.; Dillow, T.A.; Tiegs, T.N.

    1994-12-01

    Continuing benchtop studies using Hanford single-shell tank (SST) simulants and actual Oak Ridge National Laboratory (ORNL) low-level waste (LLW), employing a new denitration process for converting nitrate to ammonia and ceramic (NAC), have conclusively shown that between 85 and 99% of the nitrate can be readily converted to gaseous ammonia. In this process, aluminum powders can be used to convert alkaline, nitrate-based supernate to ammonia and an aluminum oxide-sodium aluminate-based solid. The process may be able to use contaminated aluminum scrap metal from DOE sites to effect the conversion. The final, nitrate-free ceramic product can be pressed and sintered like other ceramics or silica and/or fluxing agents can be added to form a glassy ceramic or a flowable glass product. Based upon the starting volumes of 6.2 and 3.1 M sodium nitrate solution, volume reductions of 50 to 70% were obtained for the waste form produced. Sintered pellets produced from supernate from Melton Valley Storage Tanks (MVSTs) have been leached in accordance with the 16.1 leach test for the radioelements 85 Sr and 137 Cs. Despite lengthy counting times, 85 Sr could not be detected in the leachates. 137 Cs was only slightly above background and corresponded to a leach index of 12.2 to 13.7 after 8 months of leaching. Leach testing of unsintered and sintered reactor product spiked with hazardous metals proved that both sintered and unsintered product passed the Toxicity Characteristic Leaching Procedure (TCLP) test. Design of the equipment and flowsheet for a pilot demonstration-scale system to prove the nitrate destruction portion of the NAC process and product formation is under way

  3. Operation experience with elevated ammonia

    International Nuclear Information System (INIS)

    Vankova, Katerina; Kysela, Jan; Malac, Miroslav; Petrecky, Igor; Svarc, Vladimir

    2011-01-01

    The 10 VVER units in the Czech and Slovak Republics are all in very good water chemistry and radiation condition, yet questions have arisen regarding the optimization of cycle chemistry and improved operation in these units. To address these issues, a comprehensive experimental program for different water chemistries of the primary circuit was carried out at the Rez Nuclear Research Institute, Czech Republic, with the goal of judging the influence of various water chemistries on radiation build-up. Four types of water chemistries were compared: standard VVER water chemistry (in common use), direct hydrogen dosing without ammonia, standard VVER water chemistry with elevated ammonia levels, and zinc dosing to standard VVER water chemistry. The test results showed that the types of water chemistry other than the common one have benefits for the operation of the nuclear power plant (NPP) primary circuit. Operation experience with elevated ammonia at NPP Dukovany Units 3 and 4 is presented which validates the experimental results, demonstrating improved corrosion product volume activity. (orig.)

  4. Planar waveguide sensor of ammonia

    Science.gov (United States)

    Rogoziński, Roman; Tyszkiewicz, Cuma; Karasiński, Paweł; Izydorczyk, Weronika

    2015-12-01

    The paper presents the concept of forming ammonia sensor based on a planar waveguide structure. It is an amplitude sensor produced on the basis of the multimode waveguide. The technological base for this kind of structure is the ion exchange method and the sol-gel method. The planar multimode waveguide of channel type is produced in glass substrate (soda-lime glass of Menzel-Glaser company) by the selective Ag+↔Na+ ion exchange. On the surface of the glass substrate a porous (~40%) silica layer is produced by the sol-gel method. This layer is sensitized to the presence of ammonia in the surrounding atmosphere by impregnation with Bromocresol Purple (BCP) dye. Therefore it constitutes a sensor layer. Spectrophotometric tests carried out showed about 50% reduction of cross-transmission changes of such sensor layer for a wave λ=593 nm caused by the presence of 25% ammonia water vapor in its ambience. The radiation source used in this type of sensor structure is a light emitting diode LED. The gradient channel waveguide is designed for frontal connection (optical glue) with a standard multimode telecommunications waveguide 62.5/125μm.

  5. Neutron flux monitor

    International Nuclear Information System (INIS)

    Oda, Naotaka.

    1993-01-01

    The device of the present invention greatly saves an analog processing section such as an analog filter and an analog processing circuit. That is, the device of the present invention comprises (1) a neutron flux detection means for detecting neutron fluxed in the reactor, (2) a digital filter means for dividing signals corresponding to the detected neutron fluxes into predetermined frequency band regions, (3) a calculation processing means for applying a calculation processing corresponding to the frequency band regions to the neutron flux detection signals divided by the digital filter means. With such a constitution, since the neutron detection signals are processed by the digital filter means, the accuracy is improved and the change for the property of the filter is facilitated. Further, when a neutron flux level is obtained, a calculation processing corresponding to the frequency band region can be conducted without the analog processing circuit. Accordingly, maintenance and accuracy are improved by greatly decreasing the number of parts. Further, since problems inherent to the analog circuit are solved, neutron fluxes are monitored at high reliability. (I.S.)

  6. Exergy analysis of industrial ammonia synthesis

    International Nuclear Information System (INIS)

    Kirova-Yordanova, Zornitza

    2004-01-01

    Exergy consumption of ammonia production plants depends strongly on the ammonia synthesis loop design. Due to the thermodynamically limited low degree of conversion of hydrogen-nitrogen mixture to ammonia, industrial ammonia synthesis is implemented as recycle process (so-called 'ammonia synthesis loop'). Significant quantities of reactants are recycled back to reactor, after the removal of ammonia at low temperatures. Modern ammonia synthesis plants use well-developed heat- and cold recovery to improve the reaction heat utilisation and to reduce the refrigeration costs. In this work, the exergy method is applied to estimate the effect of the most important process parameters on the exergy efficiency of industrial ammonia synthesis. A specific approach, including suitable definitions of the system boundaries and process parameters, is proposed. Exergy efficiency indexes are discussed in order to make the results applicable to ammonia synthesis loops of various designs. The dependence of the exergy losses on properly selected independent process parameters is studied. Some results from detailed exergy analysis of the most commonly used ammonia synthesis loop design configurations at a wide range of selected parameters values are shown

  7. Effect of ascorbic acid on the properties of ammonia caramel colorant additives and acrylamide formation.

    Science.gov (United States)

    Chen, Hongxing; Gu, Zhengbiao

    2014-09-01

    Ammonia caramels are among the most widely used colorant additives in the food industry. They are commonly prepared through the Maillard reaction and caramelization of mixtures of reducing sugars with ammonia or ammonium salts. Antioxidants are known to inhibit acrylamide formation during the Maillard reaction, and they may affect the properties of the ammonia caramel products. Thus, the objective of this study was to investigate the effect of the antioxidant ascorbic acid on the properties of ammonia caramel. A mixture of glucose and ammonia was allowed to react at 120 °C for 60 min in the presence of ascorbic acid at final concentrations of 0 to 0.08 M. The ammonia caramels obtained from these reactions were all positively charged. As the concentration of ascorbic acid increased, the color intensity of the ammonia caramel showed a decreasing trend, while the intensity of the fluorescence and total amount of pyrazines in the volatiles showed a tendency to increase. The addition of ascorbic acid did not result in obvious changes in the UV-visible spectra of the ammonia caramels and the types of pyrazines in the volatiles were also unchanged. It is noteworthy that the addition of 0.02 to 0.08 M ascorbic acid did reduce the formation of the by-product acrylamide, a harmful substance in food. When the concentration of ascorbic acid added reached 0.04 M, the content of acrylamide in the ammonia caramel was 20.53 μg/L, which was approximately 44% lower than that without ascorbic acid. As a result, ascorbic acid can be considered to improve the quality and safety of ammonia caramels. © 2014 Institute of Food Technologists®

  8. Contribution of ammonia-oxidizing archaea and ammonia-oxidizing bacteria to ammonia oxidation in two nitrifying reactors.

    Science.gov (United States)

    Srithep, Papitchaya; Pornkulwat, Preeyaporn; Limpiyakorn, Tawan

    2018-03-01

    In this study, two laboratory nitrifying reactors (NRI and NRII), which were seeded by sludge from different sources and operated under different operating conditions, were found to possess distinct dominant ammonia-oxidizing microorganisms. Ammonia-oxidizing archaeal (AOA) amoA genes outnumbered ammonia-oxidizing bacterial (AOB) amoA genes in reactor NRI, while only AOB amoA genes were detectable in reactor NRII. The AOA amoA gene sequences retrieved from NRI were characterized within the Nitrososphaera sister cluster of the group 1.1b Thaumarchaeota. Two inhibitors for ammonia oxidation, allylthiourea (ATU) and 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO), were applied individually and as a mixture to observe the ammonia-oxidizing activity of both microorganisms in the reactors' sludge. The results indicated that AOA and AOB jointly oxidized ammonia in NRI, while AOB played the main role in ammonia oxidation in NRII. DNA-stable isotope probing with labeled 13 C-HCO 3 - was performed on NRI sludge. Incorporation of 13 C into AOA and AOB implied that both microorganisms may perform autotrophy during ammonia oxidation. Taken together, the results from this study provide direct evidence demonstrating the contribution of AOA and AOB to ammonia oxidation in the nitrifying reactors.

  9. Electronic factors in catalysis: the volcano curve and the effect of promotion in catalytic ammonia synthesis

    DEFF Research Database (Denmark)

    Dahl, Søren; Logadottir, Ashildur; Jacobsen, C.J.H.

    2001-01-01

    to calculate how these two factors affect the energies of the intermediates and transition states in the ammonia synthesis reaction. We show that a linear relationship exists between the activation energy for N-2 dissociation and the binding energy of adsorbed nitrogen. The ammonia synthesis activity under...... promoted transition metals. We conclude that promotion is most effective for the best non-promoted catalysts and that promotion will always be essential for obtaining an optimal ammonia synthesis catalyst. Analysis of the micro-kinetic model show that the best catalysts are those with the lowest apparent...

  10. Ammonia Process by Pressure Swing Adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Dr Felix Jegede

    2010-12-27

    The overall objective of the project is to design, develop and demonstrate a technically feasible and commercially viable system to produce ammonia along with recovery of the products by adsorption separation methods and significantly decrease the energy requirement in ammonia production. This is achieved through a significantly more efficient ammonia psa recovery system. The new ammonia recovery system receives the reactor effluents and achieves complete ammonia recovery, (which completely eliminates the energy intensive refrigeration and condensation system currently used in ammonia production). It also recovers the unused reactants and recycles them back to the reactor, free of potential reactor contaminants, and without the need for re-compression and re-heat of recycle stream thereby further saving more energy. The result is a significantly lower energy consumption, along with capital cost savings.

  11. REGENERATION OF AMMONIA SOLUTION FOR CO2 CAPTURE IN POSTCOMBUSTION

    Directory of Open Access Journals (Sweden)

    CAROL TORO

    2014-01-01

    Full Text Available This study investigated enthalpy of solutions and solubility for a NH3/CO2 system. Measurements were performed in a thermoregulated Lewis-type cell reactor, temperatures ranging from 278 to 303 K and mass concentrations from 2 wt% to 5 wt%. Enthalpies of solution of CO2 and solubility have been obtained as function of loading, α (moles CO2/mol NH3. Results show that ammonia solutions concentrations of 3 and 5 wt% promote the formation of ammonium bicarbonate. Beside, ammonia concentration of 2 wt% promotes the formation of ammonium carbonate. Therefore, to use ammonia concentrations of 3 and 5 wt% need less energy that a concentration of 2 wt% to reverse the reaction. Regeneration system was simulated using Aspen plus™ software for a pulverised coal fired power plant (CF in a post-combustion process. Model analysis established that NH3 heat duty is lower than MEA and MDEA ones. The energy consumption reaches 2.83 GJ•t-1 CO2. Regarding heat duty and ammonia losses, 3 wt% NH3 is the suitable concentration to capture CO2.

  12. Ultra-clean hydrogen production by ammonia decomposition

    Directory of Open Access Journals (Sweden)

    M.E.E. Abashar

    2018-01-01

    Full Text Available A rigorous heterogeneous mathematical model is used to simulate a cascade of multi-stage fixed bed membrane reactors (MSFBMR with inter-stage heating and fresh sweep gas for the decomposition of ammonia to produce high purity hydrogen suitable for the PEM fuel cells. Different reactor configurations are compared. The comparison between a single fixed bed reactor (FBR and a single fixed bed membrane reactor (FBMR shows that the FBMR is superior to the FBR and gives 60.48% ammonia conversion higher than the FBR. However, 20.91% exit ammonia conversion obtained by the FBMR is considered to be poor. The FBMR is limited by the kinetics at low temperatures. The numerical results show that the MSFBMR of four beds achieve 100.0% ammonia conversion. It was found that the membrane plays the prime role in the displacement of the thermodynamic equilibrium. The results also show that, a linear relationship exists between the number of beds and the feed temperature and a correlation has been developed. A critical point for an effective hydrogen permeation zone has been identified. It is observed that the diffusion limitation is confined to a slim region at the entrance of the reactor. It is also observed that the heat load assumes a maximum inflection point and explanations offered. The results show that the multi-stage configuration has a promising potential to be applied successfully on-site for ultra-clean hydrogen production.

  13. Growth at low ammonium concentrations and starvation response as potential factors involved in niche differentiation among ammonia-oxidizing bacteria

    NARCIS (Netherlands)

    Bollmann, A.; Bär-Gilissen, M.J.; Laanbroek, H.J.

    2002-01-01

    In nature, ammonia-oxidizing bacteria have to compete with heterotrophic bacteria and plants for limiting amounts of ammonium. Previous laboratory experiments conducted with Nitrosomonas europaea suggested that ammonia-oxidizing bacteria are weak competitors for ammonium. To obtain a better

  14. Growth at low ammonium concentrations and starvation response as potential factors involved in niche differentiation among ammonia-oxidizing bacteria

    NARCIS (Netherlands)

    Bollmann, A.; Bär-Gilissen, M.J.; Laanbroek, H.J.

    2002-01-01

    In nature, ammonia-oxidizing bacteria have to compete with heterotrophic bacteria and plants for limiting amounts of ammonium. Previous laboratory experiments conducted with Nitrosomonas europaea suggested that ammonia-oxidizing bacteria are weak competitors for ammonium. To obtain a better insight

  15. Ammonia emission from crop residues : quantification of ammonia volatilization based on crop residue properties

    NARCIS (Netherlands)

    Ruijter, de F.J.; Huijsmans, J.F.M.

    2012-01-01

    This paper gives an overview of available literature data on ammonia volatilization from crop residues. From these data, a relation is derived for the ammonia emission depending on the N-content of crop residue.

  16. New findings on cerebral ammonia uptake in HE using functional (13)N-ammonia PET

    DEFF Research Database (Denmark)

    Sørensen, Michael; Keiding, Susanne

    2007-01-01

    ) analysed such data in patients with HE by a kinetic model accounting for transfer of (13)N-ammonia across the blood-brain barrier (BBB) and intracellular formation of (13)N-glutamine. Initial unidirectional (13)N-ammonia transfer across BBB was characterized by the permeability-surface area product PS...... metabolites was linearly correlated to arterial ammonia. In conclusion, basic brain ammonia kinetics was not changed significantly in patients with cirrhosis +/- HE compared to healthy controls. Blood ammonia seems to be the more important factor for increased brain ammonia uptake in HE. Udgivelsesdato: 2007......PET is a functional imaging technique suitable for studies of brain ammonia metabolism. Dynamic (13)N-ammonia PET yields time-courses of radioactivity concentrations in brain (PET camera) and blood (samples). Ahl et al. (Hepatology 40:73-79, 2004) and Keiding et al. (Hepatology 43:42-50, 2006...

  17. 21 CFR 862.1065 - Ammonia test system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ammonia test system. 862.1065 Section 862.1065....1065 Ammonia test system. (a) Identification. An ammonia test system is a device intended to measure ammonia levels in blood, serum, and plasma, Ammonia measurements are used in the diagnosis and treatment...

  18. Synthesis of ammonia using sodium melt

    OpenAIRE

    Kawamura, Fumio; Taniguchi, Takashi

    2017-01-01

    Research into inexpensive ammonia synthesis has increased recently because ammonia can be used as a hydrogen carrier or as a next generation fuel which does not emit CO2. Furthermore, improving the efficiency of ammonia synthesis is necessary, because current synthesis methods emit significant amounts of CO2. To achieve these goals, catalysts that can effectively reduce the synthesis temperature and pressure, relative to those required in the Haber-Bosch process, are required. Although severa...

  19. Polyaniline-based optical ammonia detector

    Science.gov (United States)

    Duan, Yixiang; Jin, Zhe; Su, Yongxuan

    2002-01-01

    Electronic absorption spectroscopy of a polyaniline film deposited on a polyethylene surface by chemical oxidation of aniline monomer at room temperature was used to quantitatively detect ammonia gas. The present optical ammonia gas detector was found to have a response time of less than 15 s, a regeneration time of less than 2 min. at room temperature, and a detection limit of 1 ppm (v/v) for ammonia, with a linear dynamic range from 180 ppm to 18,000 ppm.

  20. Carboxymethylguargum-silver nanocomposite: green synthesis, characterization and an optical sensor for ammonia detection

    International Nuclear Information System (INIS)

    Gupta, Anek Pal; Verma, Devendra Kumar

    2014-01-01

    This work describes the preparation of new carboxymethyl guar gum-silver nanocomposite (CMGG/Ag NC) by green synthesis method. For this carboxymethyl guar gum was used as a reducing agent as well as stabilizer. The silver nanoparticles obtained were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), UV–vis spectroscopy, Fourier transform infrared (FTIR) and energy dispersive x-ray analysis (EDX). The average size of the silver nanoparticles was found of ∼6 nm. Thus, the obtained CMGG/AgNPs NC was examined for optical sensing property for detection of ammonia in aqueous medium. The response time and the detection limit of ammonia in aqueous solution were detected at room temperature. It was concluded that in the future, at this room temperature optical ammonia sensor may be used for medical diagnosis and clinically for detecting low ammonia level (up to 1 ppm) in biological samples for various biomedical applications. (paper)

  1. Ammonia separation in novel bio filters

    Directory of Open Access Journals (Sweden)

    Jochen Hahne

    2017-04-01

    Full Text Available Currently used bio filters are suited for odor reduction in livestock keeping but not for ammonia separation. Therefore it was the objective to develop a novel bio filter system which was able to ensure a high and long-lasting ammonia separation. This novel bio filter, which is equipped with a pH control in a water swamp beneath the filter layer and a conductivity control for water discharge, was investigated in terms of ammonia separation and nitrogen disposition over several months under practical conditions. The results show a stable ammonia separation of more than 88 % if certain consecutively described operating conditions are kept.

  2. Sizing of an Ammonia Discharge Tank

    Directory of Open Access Journals (Sweden)

    Tuliagenda Beckfords

    2011-01-01

    Full Text Available Phosphate companies use well-stirred tanks to regulate the concentration of ammonia they discharge via their wastewater, preventing ammonia spikes from exceeding the cap set by the Environmental Protection Agency. This report discusses the methods used to determine the minimum possible volume of the tank required to regulate wastewater discharge. With this information, it was determined that the use of a stirring tank is an efficient and cost effective way to regulate ammonia discharge. Based on these results many other companies may use this method to decrease the negative effects of ammonia on the environment.

  3. Synthesis of ammonia using sodium melt.

    Science.gov (United States)

    Kawamura, Fumio; Taniguchi, Takashi

    2017-09-14

    Research into inexpensive ammonia synthesis has increased recently because ammonia can be used as a hydrogen carrier or as a next generation fuel which does not emit CO 2 . Furthermore, improving the efficiency of ammonia synthesis is necessary, because current synthesis methods emit significant amounts of CO 2 . To achieve these goals, catalysts that can effectively reduce the synthesis temperature and pressure, relative to those required in the Haber-Bosch process, are required. Although several catalysts and novel ammonia synthesis methods have been developed previously, expensive materials or low conversion efficiency have prevented the displacement of the Haber-Bosch process. Herein, we present novel ammonia synthesis route using a Na-melt as a catalyst. Using this route, ammonia can be synthesized using a simple process in which H 2 -N 2 mixed gas passes through the Na-melt at 500-590 °C under atmospheric pressure. Nitrogen molecules dissociated by reaction with sodium then react with hydrogen, resulting in the formation of ammonia. Because of the high catalytic efficiency and low-cost of this molten-Na catalyst, it provides new opportunities for the inexpensive synthesis of ammonia and the utilization of ammonia as an energy carrier and next generation fuel.

  4. Ammonia-methane combustion in tangential swirl burners for gas turbine power generation

    OpenAIRE

    Valera Medina, Agustin; Marsh, Richard; Runyon, Jon; Pugh, Daniel; Beasley, Paul; Hughes, Timothy Richard; Bowen, Philip John

    2017-01-01

    Ammonia has been proposed as a potential energy storage medium in the transition towards a low-carbon economy. This paper details experimental results and numerical calculations obtained to progress towards optimisation of fuel injection and fluidic stabilisation in swirl burners with ammonia as the primary fuel. A generic tangential swirl burner has been employed to determine flame stability and emissions produced at different equivalence ratios using ammonia–methane blends. Experiments were...

  5. Modeling combustion of ammonia/hydrogen fuel blends under gas turbine conditions

    OpenAIRE

    Xiao, Hua; Valera Medina, Agustin; Bowen, Philip J.

    2017-01-01

    To utilize ammonia as an alternative fuel for future power generation, it is essential to develop combustion chemical kinetic mechanisms which can describe in some detail the reaction characteristics and combustion properties. In the present study, a detailed chemical-kinetics mechanism is developed to validate premixed combustion characteristics of ammonia and hydrogen fuel blends comprehensively. In order to obtain a useful model for gas turbine applications, the proposed kinetic mechanism ...

  6. Moisture and temperature controls on nitrification differ among ammonia oxidizer communities from three alpine soil habitats

    Science.gov (United States)

    Osborne, Brooke B.; Baron, Jill S.; Wallenstein, Matthew D.

    2016-01-01

    Climate change is altering the timing and magnitude of biogeochemical fluxes in many high elevation ecosystems. The consequent changes in alpine nitrification rates have the potential to influence ecosystem scale responses. In order to better understand how changing temperature and moisture conditions may influence ammonia oxidizers and nitrification activity, we conducted laboratory incubations on soils collected in a Colorado watershed from three alpine habitats (glacial outwash, talus, and meadow). We found that bacteria, not archaea, dominated all ammonia oxidizer communities. Nitrification increased with moisture in all soils and under all temperature treatments. However, temperature was not correlated with nitrification rates in all soils. Site-specific temperature trends suggest the development of generalist ammonia oxidizer communities in soils with greater in situ temperature fluctuations and specialists in soils with more steady temperature regimes. Rapidly increasing temperatures and changing soil moisture conditions could explain recent observations of increased nitrate production in some alpine soils.

  7. Determinants of [13N]ammonia kinetics in hepatic PET experiments: a minimal recirculatory model

    International Nuclear Information System (INIS)

    Weiss, Michael; Roelsgaard, Klaus; Bender, Dirk; Keiding, Susanne

    2002-01-01

    The aim of this study was the development of a modelling approach for the analysis of the systemic kinetics of the tracer nitrogen-13 ammonia administered for dynamic liver scanning. The radioactive half-life of this tracer is 9.8 min, which limits the time span in which data are available in a positron emission tomography experimental setting. A circulatory pharmacokinetic model was applied to the metabolism of ammonia in anaesthetised pigs, which incorporated data from serial measurements of [ 13 N]ammonia and [ 13 N]metabolite activity in arterial and portal venous blood together with blood flow rates through the portal vein and through the hepatic artery obtained over 20 min after intravenous injection of [ 13 N]ammonia. Model analysis showed that up to 20 min after injection the time course of [ 13 N]ammonia concentration in arterial blood is primarily determined by distribution kinetics (steady-state volume of distribution 1,856±531 ml kg -1 ). Simultaneous fitting of arterial ammonia and metabolite blood concentrations allowed for estimation of the hepatic [ 13 N]ammonia clearance (10.25±1.84 ml min -1 kg -1 ), which accounted for the formation of the circulating metabolites. (orig.)

  8. Determinants of [13N]ammonia kinetics in hepatic PET experiments: a minimal recirculatory model.

    Science.gov (United States)

    Weiss, Michael; Roelsgaard, Klaus; Bender, Dirk; Keiding, Susanne

    2002-12-01

    The aim of this study was the development of a modelling approach for the analysis of the systemic kinetics of the tracer nitrogen-13 ammonia administered for dynamic liver scanning. The radioactive half-life of this tracer is 9.8 min, which limits the time span in which data are available in a positron emission tomography experimental setting. A circulatory pharmacokinetic model was applied to the metabolism of ammonia in anaesthetised pigs, which incorporated data from serial measurements of [(13)N]ammonia and [(13)N]metabolite activity in arterial and portal venous blood together with blood flow rates through the portal vein and through the hepatic artery obtained over 20 min after intravenous injection of [(13)N]ammonia. Model analysis showed that up to 20 min after injection the time course of [(13)N]ammonia concentration in arterial blood is primarily determined by distribution kinetics (steady-state volume of distribution 1,856+/-531 ml kg(-1)). Simultaneous fitting of arterial ammonia and metabolite blood concentrations allowed for estimation of the hepatic [(13)N]ammonia clearance (10.25+/-1.84 ml min(-1) kg(-1)), which accounted for the formation of the circulating metabolites.

  9. Evaluating the impact of ammonia fiber expansion (AFEX) pretreatment conditions on the cost of ethanol production.

    Science.gov (United States)

    Bals, Bryan; Wedding, Chris; Balan, Venkatesh; Sendich, Elizabeth; Dale, Bruce

    2011-01-01

    Ammonia fiber expansion (AFEX) pretreatment is an ammonia-based process for improving the susceptibility of lignocellulosic biomass to enzymatic attack. Four parameters--ammonia loading, water loading, reaction temperature, and residence time--can be varied in order to optimize AFEX pretreatment. The effect of these parameters on process economics of ethanol production was studied using a leading biorefinery model. Ammonia loading and residence time had the greatest impact on the economics of ethanol production, primarily due to processing costs for the chilled water condenser and the capital cost of the AFEX reactor. Water loading and reaction temperature had only modest impact on process economics. In addition, the impact of pretreatment conditions on makeup ammonia requirements was explored experimentally, which ranged from 15 to 25 g ammonia/kg biomass. Overall, pretreatment conditions can change the costs of ethanol production by up to 35 cents per gallon ethanol in an 850 ton/day refinery. By linking the results obtained from this Aspen model to experimental results for ethanol production and makeup ammonia recovery, this study can be used to create an economic optimum for AFEX pretreatment in contrast with simply maximizing fermentable sugar production. Copyright © 2010 Elsevier Ltd. All rights reserved.

  10. Nitrogen-13-labeled ammonia for myocardial imaging

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, W.F.; Fill, H.R.; Harper, P.V.

    1977-01-01

    Cyclotron-produced nitrogen-13 (half-life 10 min), as labeled ammonia (/sup 13/NH/sub 4//sup +/), has been evaluated as a myocardial perfusion imaging agent. The regional myocardial uptake of /sup 13/NH/sub 4//sup +/ has been shown to be proportional to regional tissue perfusion in animal studies. Intravenously administered /sup 13/NH/sub 4//sup +/ is rapidly cleared from the circulation, being extracted by the liver (15 percent), lungs, myocardium (2 percent--4 percent), brain, kidney, and bladder. Myocardial ammonia is metabolized mainly to glutamine via the glutamine synthetase pathway. Pulmonary uptake is substantial, but usually transient, except in smokers where clearance may be delayed. The positron annihilation irradiation (511 keV) of /sup 13/N may be imaged with a scintillation camera, using either a specially designed tungsten collimator or a pinhole collimator. After early technical problems with collimation and the production method of /sup 13/NH/sub 4//sup +/ were overcome, reproducible high quality myocardial images were consistently obtained. The normal myocardial image was established to be of a homogeneous ''doughnut'' configuration. Imaging studies performed in patients with varying manifestations of ischemic and valvular heart disease showed a high incidence of localized perfusion defects, especially in patients with acute myocardial infarction. Sequential studies at short intervals in patients with acute infarction showed correlation between alterations in regional perfusion and the clinical course of the patient. It is concluded that myocardial imaging with /sup 13/NH/sub 4//sup +/ and a scintillation camera provides a valid and noninvasive means of assessing regional myocardial perfusion. This method is especially suitable for sequential studies of acute cardiac patients at short intervals. Coincidence imaging of the 511 keV annihilation irradiation provides a tomographic and potentially quantitative assessment of the

  11. The influence of trace NO(2) on the kinetics of ammonia oxidation and the characteristics of nitrogen removal from wastewater.

    Science.gov (United States)

    Zhang, Daijun; Cai, Qing; Zu, Bo; Bai, Cui; Zhang, Ping

    2010-01-01

    Ammonia oxidizing bacteria-enriched sludge was obtained in a sequencing batch reactor with synthetic wastewater. Batch tests of ammonia oxidation were carried out with the sludge, in the presence of only trace NO(2) and in the presence of O(2) and trace NO(2), respectively. The Andrews model is used to describe NO(2)-dependent ammonia oxidation. The maximum ammonia oxidation rate of 139.11 mg N.(g sludge COD h)(-1), occurred in the presence of 21% O(2) and 100 ppm NO(2), which was 3 times higher than the aerobic ammonia oxidation rate without NO(2). The kinetic model of ammonia oxidation in the presence of O(2) and trace NO(2) is developed, and the function of NO(2) apparently enhancing ammonia oxidation is suggested. The maximal nitrogen removel of 34.19% occurred at the 21% O(2) and 100 ppm NO(2) in the mixed gases. Nitrogen removal principally depended on the denitrification activity and NO(2)-dependent ammonia oxidation activity of ammonia-oxidizing bacteria (AOB).

  12. Mathematical Modeling of Ammonia Electro-Oxidation on Polycrystalline Pt Deposited Electrodes

    Science.gov (United States)

    Diaz Aldana, Luis A.

    The ammonia electrolysis process has been proposed as a feasible way for electrochemical generation of fuel grade hydrogen (H2). Ammonia is identified as one of the most suitable energy carriers due to its high hydrogen density, and its safe and efficient distribution chain. Moreover, the fact that this process can be applied even at low ammonia concentration feedstock opens its application to wastewater treatment along with H 2 co-generation. In the ammonia electrolysis process, ammonia is electro-oxidized in the anode side to produce N2 while H2 is evolved from water reduction in the cathode. A thermodynamic energy requirement of just five percent of the energy used in hydrogen production from water electrolysis is expected from ammonia electrolysis. However, the absence of a complete understanding of the reaction mechanism and kinetics involved in the ammonia electro-oxidation has not yet allowed the full commercialization of this process. For that reason, a kinetic model that can be trusted in the design and scale up of the ammonia electrolyzer needs to be developed. This research focused on the elucidation of the reaction mechanism and kinetic parameters for the ammonia electro-oxidation. The definition of the most relevant elementary reactions steps was obtained through the parallel analysis of experimental data and the development of a mathematical model of the ammonia electro-oxidation in a well defined hydrodynamic system, such as the rotating disk electrode (RDE). Ammonia electro-oxidation to N 2 as final product was concluded to be a slow surface confined process where parallel reactions leading to the deactivation of the catalyst are present. Through the development of this work it was possible to define a reaction mechanism and values for the kinetic parameters for ammonia electro-oxidation that allow an accurate representation of the experimental observations on a RDE system. Additionally, the validity of the reaction mechanism and kinetic parameters

  13. Surface Flux Modeling for Air Quality Applications

    Directory of Open Access Journals (Sweden)

    Limei Ran

    2011-08-01

    Full Text Available For many gasses and aerosols, dry deposition is an important sink of atmospheric mass. Dry deposition fluxes are also important sources of pollutants to terrestrial and aquatic ecosystems. The surface fluxes of some gases, such as ammonia, mercury, and certain volatile organic compounds, can be upward into the air as well as downward to the surface and therefore should be modeled as bi-directional fluxes. Model parameterizations of dry deposition in air quality models have been represented by simple electrical resistance analogs for almost 30 years. Uncertainties in surface flux modeling in global to mesoscale models are being slowly reduced as more field measurements provide constraints on parameterizations. However, at the same time, more chemical species are being added to surface flux models as air quality models are expanded to include more complex chemistry and are being applied to a wider array of environmental issues. Since surface flux measurements of many of these chemicals are still lacking, resistances are usually parameterized using simple scaling by water or lipid solubility and reactivity. Advances in recent years have included bi-directional flux algorithms that require a shift from pre-computation of deposition velocities to fully integrated surface flux calculations within air quality models. Improved modeling of the stomatal component of chemical surface fluxes has resulted from improved evapotranspiration modeling in land surface models and closer integration between meteorology and air quality models. Satellite-derived land use characterization and vegetation products and indices are improving model representation of spatial and temporal variations in surface flux processes. This review describes the current state of chemical dry deposition modeling, recent progress in bi-directional flux modeling, synergistic model development research with field measurements, and coupling with meteorological land surface models.

  14. Measuring fluxes of mineral nutrients and toxicants in plants with radioactive tracers.

    Science.gov (United States)

    Coskun, Devrim; Britto, Dev T; Hamam, Ahmed M; Kronzucker, Herbert J

    2014-08-22

    Unidirectional influx and efflux of nutrients and toxicants, and their resultant net fluxes, are central to the nutrition and toxicology of plants. Radioisotope tracing is a major technique used to measure such fluxes, both within plants, and between plants and their environments. Flux data obtained with radiotracer protocols can help elucidate the capacity, mechanism, regulation, and energetics of transport systems for specific mineral nutrients or toxicants, and can provide insight into compartmentation and turnover rates of subcellular mineral and metabolite pools. Here, we describe two major radioisotope protocols used in plant biology: direct influx (DI) and compartmental analysis by tracer efflux (CATE). We focus on flux measurement of potassium (K(+)) as a nutrient, and ammonia/ammonium (NH3/NH4(+)) as a toxicant, in intact seedlings of the model species barley (Hordeum vulgare L.). These protocols can be readily adapted to other experimental systems (e.g., different species, excised plant material, and other nutrients/toxicants). Advantages and limitations of these protocols are discussed.

  15. Method for releasing hydrogen from ammonia borane

    Science.gov (United States)

    Varma, Arvind; Diwan, Moiz; Shafirovich, Evgeny; Hwang, Hyun-Tae; Al-Kukhun, Ahmad

    2013-02-19

    A method of releasing hydrogen from ammonia borane is disclosed. The method comprises heating an aqueous ammonia borane solution to between about 80-135.degree. C. at between about 14.7 and 200 pounds per square inch absolute (psia) to release hydrogen by hydrothermolysis.

  16. Chilled ammonia process for CO2 capture

    DEFF Research Database (Denmark)

    Darde, Victor Camille Alfred; Thomsen, Kaj; van Well, Willy J. M

    2009-01-01

    The chilled ammonia process absorbs the CO2 at low temperature (2-10 degrees C). The heat of absorption of carbon dioxide by ammonia is significantly lower than for amines. In addition, degradation problems can be avoided and a high carbon dioxide capacity is achieved. Hence, this process shows...

  17. Regeneration of ammonia borane from polyborazylene

    Science.gov (United States)

    Sutton, Andrew; Gordon, John C; Ott, Kevin C; Burrell, Anthony K

    2013-02-05

    Method of producing ammonia borane, comprising providing a reagent comprising a dehydrogenated material in a suitable solvent; and combining the reagent with a reducing agent comprising hydrazine, a hydrazine derivative, or combinations thereof, in a reaction which produces a mixture comprising ammonia borane.

  18. Chilled Ammonia Process for CO2 Capture

    DEFF Research Database (Denmark)

    Darde, Victor Camille Alfred; Thomsen, Kaj; Well, Willy J.M. van

    2010-01-01

    The chilled ammonia process absorbs the CO2 at low temperature (2–10°C). The heat of absorption of carbon dioxide by ammonia is significantly lower than for amines. In addition, degradation problems can be avoided and a high carbon dioxide capacity is achieved. Hence, this process shows good...

  19. Atmospheric behaviour of ammonia and ammonium

    NARCIS (Netherlands)

    Asman, W.A.H.

    1987-01-01

    1.4.1 Scope of this thesis

    A few models for ammonia and ammonium exist. Russell et al. (1983) made a multi-layer Lagrangian transport model describing the transport and formation of ammonium nitrate aerosol for California. They did not take reactions of ammonia and sulphuric acid

  20. Reducing ammonia volatilization from compound fertilizers ...

    African Journals Online (AJOL)

    Ammonia volatilization is a direct loss of available nitrogen in agriculture. The objective of this study was to determine the effect of amending NPK fertilizer with different rates of clinoptilolite zeolite on ammonia volatilization, soil exchangeable ammonium, and available nitrate. Seven treatments evaluated were: 250 g soil ...

  1. Ammonia Sensor Using Wavelength Modulation Spectroscopy

    KAUST Repository

    Farooq, Aamir

    2015-09-01

    An ammonia sensor can include a laser detector configured to provide stable sample readings. The sensor can implement a method including processing the recorded intensity of the laser beam to determine a first harmonic component and a second harmonic component and the amount of ammonia in the sample.

  2. Ammonia Solubility in High Concentration Salt Solutions

    International Nuclear Information System (INIS)

    HEDENGREN, D.C.

    2000-01-01

    Solubility data for ammonia in water and various dilute solutions are abundant in the literature. However, there is a noticeable lack of ammonia solubility data for high salt, basic solutions of various mixtures of salts including those found in many of the Hanford Washington underground waste tanks. As a result, models based on solubility data for dilute salt solutions have been used to extrapolate to high salt solutions. These significant extrapolations need to be checked against actual laboratory data. Some indirect vapor measurements have been made. A more direct approach is to determine the ratio of solubility of ammonia in water to its solubility in high salt solutions. In various experiments, pairs of solutions, one of which is water and the other a high salt solution, are allowed to come to equilibrium with a common ammonia vapor pressure. The ratio of concentrations of ammonia in the two solutions is equal to the ratio of the respective ammonia solubilities (Henry's Law constants) at a given temperature. This information can then be used to refine the models that predict vapor space compositions of ammonia. Ammonia at Hanford is of concern because of its toxicity in the environment and its contribution to the flammability of vapor space gas mixtures in waste tanks

  3. Ammonia Concentrations in Different Aquaculture Holding Tanks ...

    African Journals Online (AJOL)

    High unionized ammonia recorded in the collapsible and concrete ponds was from excretion of high protein rich feed, decomposition of uneaten feed, high stocking density, low water exchange rates, water source and the alkaline medium of the systems. Low unionized ammonia in earthen pond and natural pond was ...

  4. Measuring ammonia emissions from manured fields

    NARCIS (Netherlands)

    Berkhout, A.J.C.; Hoff, G.R.; Bergwerff, J.B.; Swart, D.P.J.; Hensen, A.; Kraai, A.; Bleeker, A.; Huijsmans, J.F.M.; Mosquera Losada, J.; Pul, van W.A.J.

    2008-01-01

    In this report, 2 novel instruments are described that are able to measure the ammonia emissions of manured fields. The 1st instrument, developed and operated by ECN, is a tuneable diode laser spectrometer (TDL), mounted in a van. It is used to measure the ammonia concentration patterns downwind

  5. Enrichment of ammonia concentration from aqua-ammonia vapors by using 3A molecular sieve

    International Nuclear Information System (INIS)

    Chiou, J.S.; Lin, T.M.; She, K.Y.; Chen, W.M.

    2009-01-01

    In aqua-ammonia refrigeration systems, the ammonia is the refrigerant and the water is the absorbent, the vapor produced in the generator always contains a small fraction of water. The removed of this residual water is a crucial issue in order to guarantee a reliable and efficient operation of these systems. Currently, the thermal distillation methods (via a rectifier and/or an analyzer) are used to further separate the water from aqua-ammonia mixtures. In this study, a molecular sieve module is used for ammonia purification. A thermal system with a 3A molecular sieve module was set up, and the conditions of working fluid entering into the sieve module is similar to that entering into the rectifier tower of a typical aqua-ammonia absorption system. Results from ammonia enrichment tests indicate the concentration of ammonia can be raised from about 80% up to about 99% if siever installation was properly arranged.

  6. Solid solution barium–strontium chlorides with tunable ammonia desorption properties and superior storage capacity

    International Nuclear Information System (INIS)

    Bialy, Agata; Jensen, Peter B.; Blanchard, Didier; Vegge, Tejs; Quaade, Ulrich J.

    2015-01-01

    Metal halide ammines are very attractive materials for ammonia absorption and storage—applications where the practically accessible or usable gravimetric and volumetric storage densities are of critical importance. Here we present, that by combining advanced computational materials prediction with spray drying and in situ thermogravimetric and structural characterization, we synthesize a range of new, stable barium-strontium chloride solid solutions with superior ammonia storage densities. By tuning the barium/strontium ratio, different crystallographic phases and compositions can be obtained with different ammonia ab- and desorption properties. In particular it is shown, that in the molar range of 35–50% barium and 65–50% strontium, stable materials can be produced with a practically usable ammonia density (both volumetric and gravimetric) that is higher than any of the pure metal halides, and with a practically accessible volumetric ammonia densities in excess of 99% of liquid ammonia. - Graphical abstract: Thermal desorption curves of ammonia from Ba x Sr (1−x) Cl 2 mixtures with x equal to 0.125, 0.25 and 0.5 and atomic structure of Sr(NH 3 ) 8 Cl 2 . - Highlights: • Solid solutions of strontium and barium chloride were synthesized by spray drying. • Adjusting molar ratios led to different crystallographic phases and compositions. • Different molar ratios led to different ammonia ab-/desorption properties. • 35–50 mol% BaCl 2 in SrCl 2 yields higher ammonia density than any other metal halide. • DFT calculations can be used to predict properties of the mixtures

  7. Surface-atmosphere exchange of ammonia over peatland using QCL-based eddy-covariance measurements and inferential modeling

    DEFF Research Database (Denmark)

    Zöll, Undine; Brümmer, Christian; Schrader, Frederik

    2016-01-01

    Recent advances in laser spectrometry offer new opportunities to investigate ecosystem-atmosphere exchange of environmentally relevant trace gases. In this study, we demonstrate the applicability of a quantum cascade laser (QCL) absorption spectrometer to continuously measure ammonia concentrations...... at high time resolution and thus to quantify the net exchange between a seminatural peatland ecosystem and the atmosphere based on the eddy-covariance approach. Changing diurnal patterns of both ammonia concentration and fluxes were found during different periods of the campaign. We observed a clear......, and surface wetness were identified to partially regulate ammonia exchange at the site, the seasonal concentration pattern was clearly dominated by agricultural practices in the surrounding area. Comparing the results of a compensation point model with our measurement-based flux estimates showed considerable...

  8. Critical flux determination by flux-stepping

    DEFF Research Database (Denmark)

    Beier, Søren; Jonsson, Gunnar Eigil

    2010-01-01

    In membrane filtration related scientific literature, often step-by-step determined critical fluxes are reported. Using a dynamic microfiltration device, it is shown that critical fluxes determined from two different flux-stepping methods are dependent upon operational parameters such as step......, such values are more or less useless in itself as critical flux predictors, and constant flux verification experiments have to be conducted to check if the determined critical fluxes call predict sustainable flux regimes. However, it is shown that using the step-by-step predicted critical fluxes as start...

  9. Ammonia and urea permeability of mammalian aquaporins

    DEFF Research Database (Denmark)

    Litman, Thomas; Søgaard, Rikke; Zeuthen, Thomas

    2009-01-01

    and 9 are found together with Rh proteins in cells exposed to portal blood coming from the intestine. In the kidney, AQP3 might participate in the excretion of NH(4) (+) in the collecting duct. The interplay between the ammonia-permeable aquaporins and the other types of ammonia- and urea......The human aquaporins,AQP3,AQP7, AQP8,AQP9, and possibly AQP10, are permeable to ammonia, and AQP7, AQP9, and possibly AQP3, are permeable to urea. In humans, these aquaporins supplement the ammonia transport of the Rhesus (Rh) proteins and the urea transporters (UTs). The mechanism by which...... ammonium is transported by aquaporins is not fully resolved. A comparison of transport equations, models, and experimental data shows that ammonia is transported in its neutral form, NH(3). In the presence of NH(3), the aquaporin stimulates H(+) transport. Consequently, this transport of H(+) is only...

  10. Clinical utility of breath ammonia for evaluation of ammonia physiology in healthy and cirrhotic adults

    Science.gov (United States)

    Spacek, Lisa A; Mudalel, Matthew; Tittel, Frank; Risby, Terence H; Solga, Steven F

    2016-01-01

    Blood ammonia is routinely used in clinical settings to assess systemic ammonia in hepatic encephalopathy and urea cycle disorders. Despite its drawbacks, blood measurement is often used as a comparator in breath studies because it is a standard clinical test. We sought to evaluate sources of measurement error and potential clinical utility of breath ammonia compared to blood ammonia. We measured breath ammonia in real time by quartz enhanced photoacoustic spectrometry and blood ammonia in 10 healthy and 10 cirrhotic participants. Each participant contributed 5 breath samples and blood for ammonia measurement within 1 h. We calculated the coefficient of variation (CV) for 5 breath ammonia values, reported medians of healthy and cirrhotic participants, and used scatterplots to display breath and blood ammonia. For healthy participants, mean age was 22 years (±4), 70% were men, and body mass index (BMI) was 27 (±5). For cirrhotic participants, mean age was 61 years (±8), 60% were men, and BMI was 31 (±7). Median blood ammonia for healthy participants was within normal range, 10 μmol L−1 (interquartile range (IQR), 3–18) versus 46 μmol L−1 (IQR, 23–66) for cirrhotic participants. Median breath ammonia was 379 pmol mL−1 CO2 (IQR, 265–765) for healthy versus 350 pmol mL−1 CO2 (IQR, 180–1013) for cirrhotic participants. CV was 17 ± 6%. There remains an important unmet need in the evaluation of systemic ammonia, and breath measurement continues to demonstrate promise to fulfill this need. Given the many differences between breath and blood ammonia measurement, we examined biological explanations for our findings in healthy and cirrhotic participants. We conclude that based upon these preliminary data breath may offer clinically important information this is not provided by blood ammonia. PMID:26658550

  11. Biogas upgrading by chemical absorption using ammonia rich absorbents derived from wastewater.

    Science.gov (United States)

    McLeod, Andrew; Jefferson, Bruce; McAdam, Ewan J

    2014-12-15

    The use of ammonia (NH3) rich wastewaters as an ecological chemical absorption solvent for the selective extraction of carbon dioxide (CO2) during biogas upgrading to 'biomethane' has been studied. Aqueous ammonia absorbents of up to 10,000 gNH3 m(-3) demonstrated CO2 absorption rates higher than recorded in the literature for packed columns using 20,000-80,000 g NH3 m(-3) which can be ascribed to the process intensification provided by the hollow fibre membrane contactor used in this study to support absorption. Centrifuge return liquors (2325 g m(-3) ionised ammonium, NH4(+)) and a regenerant (477 gNH4(+) m(-3)) produced from a cationic ion exchanger used to harvest NH4(+) from crude wastewater were also tested. Carbon dioxide fluxes measured for both wastewaters compared reasonably with analogue ammonia absorption solvents of equivalent NH3 concentration. Importantly, this demonstrates that ammonia rich wastewaters can facilitate chemically enhanced CO2 separation which eliminates the need for costly exogenic chemicals or complex chemical handling which are critical barriers to implementation of chemical absorption. When testing NH3 analogues, the potential to recover the reaction product ammonium bicarbonate (NH4HCO3) in crystalline form was also illustrated. This is significant as it suggests a new pathway for ammonia separation which avoids biological nitrification and produces ammonia stabilised into a commercially viable fertiliser (NH4HCO3). However, in real ammonia rich wastewaters, sodium bicarbonate and calcium carbonate were preferentially formed over NH4HCO3 although it is proposed that NH4HCO3 can be preferentially formed by manipulating both ion exchange and absorbent chemistry. Copyright © 2014. Published by Elsevier Ltd.

  12. Vertical Distribution and Flux of Nutrients in the Sediments of the Mangrove Reclamation Region of Muara Angke Kapuk, Jakarta

    Directory of Open Access Journals (Sweden)

    Anna Ida Sunaryo Purwiyanto

    2012-12-01

    Full Text Available The reclaimed mangrove estuary in Muara Angke Kapuk is a reclaimed area that has not evaded the impacted of pollution and waste in the areas surrounding Cengkareng, Jakarta. This is apparent from the fact that almost all sediments under the mangrove trees are buried under heaps of plastic trash. However, the reclaimed region still has variety of organism, which indicating that the region still has an internal carrying capacity, especially nutrients from sediment. The purpose of this research was to examine the condition of sediment nutrients in this mangrove reclamation region. The research was conducted by taking water samples using a modification of the stratified cup at a sediment depth of 0-15 cm with depth intervals of 2.5 cm, and taking sediment samples using the sediment ring. Pore water samples were measured for dissolved oxygen (DO and concentrations of ammonia, nitrite, nitrate, and phosphate. Sediment samples were used to obtain porosity values. The data obtained is used to make vertical concentration profiles and analysis of vertical nutrient flux. Vertical nutrient flux analysis was performed with the aid of QUAL2K software version 2.11. The results showed different vertical distributions and flux of nutrients, where influx for ammonia and phosphate and an increase in line with increasing sediment depth, while nitrate efflux and a decreased concentration. The flux calculation of nitrite as transitory nutrient was not done, but the concentration decreased after a depth of 2.5 cm. This indicates that the high contamination on the surface does not prevent the natural chemical processes so the reclaimed region can still provide nutritional support for its organism.

  13. An optrode for photometric detection of ammonia in air

    Science.gov (United States)

    Buzanovskii, V. A.

    2017-10-01

    A scheme of constructing an LED optrode for photometric detection of ammonia in air is considered. The components of the device are (1) a glass plate coated with a film of polydimethylsiloxane with an ion-coupled cation of brilliant-green dye, (2) an LED emitting at a wavelength of 655 nm, and (3) a metal housing. The nominal static conversion function, sensitivity, and relative measurement error of the device are analyzed on the basis of mathematical modeling. The obtained results allow one to design an LED optrode capable of carrying out control for automated technological processes, solving problems in the area of security, etc. The device provides the ability to create photometric gas analyzers of ammonia with small overall dimensions, power consumption, and cost.

  14. AMMONOX-Ammonia for enhancing biogas yield & reducing NOx

    DEFF Research Database (Denmark)

    Gavala, Hariklia N.; Kristensen, P.G.; Paamand, K.

    2013-01-01

    The continuously increasing demand for renewable energy sources renders anaerobic digestion to one of the most promising technologies for renewable energy production. Due to the animal production intensification, manure is being used as the primary feedstock for most of the biogas plants. However......, biogas plants digesting liquid manure alone are not economically viable due to the relatively low organic content of the manure, usually 3-5%.Thus, their economical profitable operation relies partly on increasing the methane yield from manure, and especially of its solid fraction, usually called...... of innovative ammonia recovery technology and c) the coupling of the excess ammonia obtained from manure with the catalytic elimination of NOx emissions when the biogas is used for subsequent electricity generation with gas engines....

  15. Vapor Phase Catalytic Ammonia Reduction

    Science.gov (United States)

    Flynn, Michael T.; Harper, Lynn D. (Technical Monitor)

    1994-01-01

    This paper discusses the development of a Vapor Phase Catalytic Ammonia Reduction (VPCAR) teststand and the results of an experimental program designed to evaluate the potential of the technology as a water purification process. In the experimental program the technology is evaluated based upon product water purity, water recovery rate, and power consumption. The experimental work demonstrates that the technology produces high purity product water and attains high water recovery rates at a relatively high specific power consumption. The experimental program was conducted in 3 phases. In phase I an Igepon(TM) soap and water mixture was used to evaluate the performance of an innovative Wiped-Film Rotating-Disk evaporator and associated demister. In phase II a phenol-water solution was used to evaluate the performance of the high temperature catalytic oxidation reactor. In phase III a urine analog was used to evaluate the performance of the combined distillation/oxidation functions of the processor.

  16. A rigorous calculation of the critical point from the fundamental equation of state for the water + ammonia mixture

    Energy Technology Data Exchange (ETDEWEB)

    Akasaka, Ryo [Faculty of Humanities, Kyushu Lutheran College, 3-12-16 Kurokami, Kumamoto 860-8520 (Japan)

    2009-01-15

    The critical point of the water + ammonia mixture was calculated directly from the Helmholtz free energy formulation. The calculation was performed according to the critical point criteria expressed in terms of the derivatives of the Helmholtz free energy with respect to mole numbers. Smooth critical locus linking between the critical points of pure water and ammonia was obtained. The critical locus showed a good agreement with the most reliable experimental data. Simple correlations for the critical temperature, pressure, and molar volume for a given composition were developed. The information obtained in this study is helpful for design and simulation of the cycles using the water + ammonia mixture as working fluid. (author)

  17. IRIS Toxicological Review of Ammonia (Revised External ...

    Science.gov (United States)

    In August 2013, EPA submitted a revised draft IRIS assessment of ammonia to the agency's Science Advisory Board (SAB) and posted this draft on the IRIS website. EPA had previously released a draft of the assessment for public comment, held a public meeting about the draft, and then revised it based on the comments received. The SAB CAAC-Ammonia panel will review this draft assessment. Details about the meeting dates, times, and location are available via the Federal Register Notice posted on March 25, 2014. The SAB provided information on how the public can participate in the external peer review meetings, as well as instructions about how to provide comments to the SAB in the notice. Additional information on the SAB review of ammonia is on the SAB website. Report Information: The Toxicological Review of Ammonia was originally released for a 60-day public comment period on June 8, 2012. [Federal Register Notice Jun 8, 2012] EPA revised the toxicological review in response to the public comments received. EPA has released the revised external review draft ammonia assessment and the SAB CAAC is conducting a peer review of the scientific basis supporting the assessment that will appear in the Integrated Risk Information System (IRIS) database. Information regarding the peer review can be found at the SAB review of ammonia website. EPA is undertaking an Integrated Risk Information System (IRIS) health assessment for ammonia. IRIS is an EPA database cont

  18. Resveratrol Prevents Ammonia Toxicity in Astroglial Cells

    Science.gov (United States)

    Guerra, Maria Cristina; Leite, Marina Concli; Souza, Diogo Onofre; Gonçalves, Carlos-Alberto; Gottfried, Carmem

    2012-01-01

    Ammonia is implicated as a neurotoxin in brain metabolic disorders associated with hyperammonemia. Acute ammonia toxicity can be mediated by an excitotoxic mechanism, oxidative stress and nitric oxide (NO) production. Astrocytes interact with neurons, providing metabolic support and protecting against oxidative stress and excitotoxicity. Astrocytes also convert excess ammonia and glutamate into glutamine via glutamine synthetase (GS). Resveratrol, a polyphenol found in grapes and red wines, exhibits antioxidant and anti-inflammatory properties and modulates glial functions, such as glutamate metabolism. We investigated the effect of resveratrol on the production of reactive oxygen species (ROS), GS activity, S100B secretion, TNF-α, IL-1β and IL-6 levels in astroglial cells exposed to ammonia. Ammonia induced oxidative stress, decreased GS activity and increased cytokines release, probably by a mechanism dependent on protein kinase A (PKA) and extracellular signal-regulated kinase (ERK) pathways. Resveratrol prevented ammonia toxicity by modulating oxidative stress, glial and inflammatory responses. The ERK and nuclear factor-κB (NF-κB) are involved in the protective effect of resveratrol on cytokines proinflammatory release. In contrast, other antioxidants (e.g., ascorbic acid and trolox) were not effective against hyperammonemia. Thus, resveratrol could be used to protect against ammonia-induced neurotoxicity. PMID:23284918

  19. Resveratrol prevents ammonia toxicity in astroglial cells.

    Directory of Open Access Journals (Sweden)

    Larissa Daniele Bobermin

    Full Text Available Ammonia is implicated as a neurotoxin in brain metabolic disorders associated with hyperammonemia. Acute ammonia toxicity can be mediated by an excitotoxic mechanism, oxidative stress and nitric oxide (NO production. Astrocytes interact with neurons, providing metabolic support and protecting against oxidative stress and excitotoxicity. Astrocytes also convert excess ammonia and glutamate into glutamine via glutamine synthetase (GS. Resveratrol, a polyphenol found in grapes and red wines, exhibits antioxidant and anti-inflammatory properties and modulates glial functions, such as glutamate metabolism. We investigated the effect of resveratrol on the production of reactive oxygen species (ROS, GS activity, S100B secretion, TNF-α, IL-1β and IL-6 levels in astroglial cells exposed to ammonia. Ammonia induced oxidative stress, decreased GS activity and increased cytokines release, probably by a mechanism dependent on protein kinase A (PKA and extracellular signal-regulated kinase (ERK pathways. Resveratrol prevented ammonia toxicity by modulating oxidative stress, glial and inflammatory responses. The ERK and nuclear factor-κB (NF-κB are involved in the protective effect of resveratrol on cytokines proinflammatory release. In contrast, other antioxidants (e.g., ascorbic acid and trolox were not effective against hyperammonemia. Thus, resveratrol could be used to protect against ammonia-induced neurotoxicity.

  20. Measured and simulated nitrogen fluxes after field application of food-processing and municipal organic wastes.

    Science.gov (United States)

    Parnaudeau, V; Génermont, S; Hénault, C; Farrugia, A; Robert, P; Nicolardot, B

    2009-01-01

    The aims of this study were to (i) assess N fluxes (mineralization, volatilization, denitrification, leaching) caused by spreading various organic wastes from food-processing industries during a field experiment, and (ii) to identify the main factors affecting N transformation processes after field spreading. Experimental treatments including the spreading of six types of waste and a control soil were set up in August 2000 and studied for 22 mo under bare soil conditions. Ammonia and nitrous oxide emissions, and nitrogen mineralization were measured in experimental devices and extrapolated to field conditions or computed in calculation models. The ammonia emissions varied from 80 to 580 g kg(-1) NH4+-N applied, representing 0 to 90 g N kg(-1) total N applied. Under these meteorologically favorable conditions (dry and warm weather), waste pH was the main factor affecting volatilization rates. Cumulated N2O-N fluxes were estimated at 2 to 5 g kg(-1) total N applied, which was quite low due to the low soil water content during the experimental period; water-filled pore space (WFPS) was confirmed as the main factor affecting N2O fluxes. Nitrogen mineralization from wastes represented 126 to 723 g N kg(-1) organic N added from the incorporation date to 14 May 2001 and was not related to the organic C to organic N ratio of wastes. Nitrogen lost by leaching during the equivalent period ranged from 30 to 890 g kg(-1) total N applied. The highest values were obtained for wastes having the highest inorganic N content and mineralization rates.

  1. Transformation of ammonia i biological airfilters

    DEFF Research Database (Denmark)

    Nielsen, Lars Peter; Sørensen, Karen; Andersen, Mathias

    2007-01-01

    Ammonia is a major compound in ventilation air from animal houses. In biological filters it is with varying efficiency transformed by physical, biological, and chemical processes and ends up as ammonium, nitrate, and nitrite dissolved in water and as dinitrogen, nitrous oxide and nitric oxide...... nitrite oxidation only appeared in locations with minimal ammonia and nitrite levels. Nitrous oxide emission depended on anoxic microsites, and nitric oxide production was associated with nitrite accumulation. Water and biomass management appear to be the important tools for optimization of ammonia...

  2. Electrochemical monitoring of ammonia during anaerobic digestion

    DEFF Research Database (Denmark)

    Zhao, Nannan; Angelidaki, Irini; Zhang, Yifeng

    Ammonia is known as key inhibitor to methanogens in anaerobic digestion (AD) process. It’s of importance to develop efficient tool for ammonia monitoring. In this study, an electrolysis cell (EC) coupled with a complete nitrification reactor was developed as sensor for real time and online......-rich digesters. It was observed that the initial transient currents (0 min) were linearly corresponding to the ammonia levels (from 0 to 95.75 mg/L NH4+-N, R2 = 0.9673). Finally, this new sensor was tested with real AD effluent and the results showed no significant difference with that measured by conventional...

  3. Ammonia complexes of metals in aqueous solutions with high concentrations of ammonia

    International Nuclear Information System (INIS)

    Padar, T.G.; Novikov, L.K.; Stupko, T.V.; Isaev, I.D.; Pashkov, G.L.; Mironov, V.E.

    1991-01-01

    Potentiometric method, glass electrodes and Bierrum function were used to study the formation of ammonia complexes of magnesium, calcium, cadmium, zinc, copper(2) and silver in 2.0 mol/dm 3 aqueous solutions of ammonia nitrate with 0-18 mol/dm 3 ammonia concentrations at 25.0 deg C. Step constants of stability of studied complexes were calculated and their compositions were determined with account of nonideal character of aqueous-salt solutions with ammonia concentrations above 1.0 mol/dm 3 . Values of correction effects on salting out ammonia action for Bierrum function in solutions with 1.0-18 mol/dm 3 ammonia concentrations were found

  4. Ammonia/Hydrogen Mixtures in an SI-Engine

    DEFF Research Database (Denmark)

    Mørch, Christian Sandersen; Bjerre, Andreas; Gøttrup, Morten Piil

    2011-01-01

    In recent years there has been increasing focus on using metal ammine complexes for ammonia storage. In this paper a fuel system for ammonia fuelled internal combustion engines using metal ammine complexes as ammonia storage is analyzed. The use of ammonia/hydrogen mixtures as an SI-engine fuel...

  5. Ammonia as a Suitable Fuel for Fuel Cells

    International Nuclear Information System (INIS)

    Lan, Rong; Tao, Shanwen

    2014-01-01

    Ammonia, an important basic chemical, is produced at a scale of 150 million tons per year. Half of hydrogen produced in chemical industry is used for ammonia production. Ammonia containing 17.5 wt% hydrogen is an ideal carbon-free fuel for fuel cells. Compared to hydrogen, ammonia has many advantages. In this mini-review, the suitability of ammonia as fuel for fuel cells, the development of different types of fuel cells using ammonia as the fuel and the potential applications of ammonia fuel cells are briefly reviewed.

  6. Ammonia as a Suitable Fuel for Fuel Cells

    OpenAIRE

    Lan, Rong; Tao, Shanwen

    2014-01-01

    Ammonia, an important basic chemical, is produced at a scale of 150 million tons per year. Half of hydrogen produced in chemical industry is used for ammonia production. Ammonia containing 17.5 wt% hydrogen is an ideal carbon-free fuel for fuel cells. Compared to hydrogen, ammonia has many advantages. In this mini-review, the suitability of ammonia as fuel for fuel cells, the development of different types of fuel cells using ammonia as the fuel and the potential applications of ammonia fuel ...

  7. Ammonia as a suitable fuel for fuel cells

    Directory of Open Access Journals (Sweden)

    Rong eLan

    2014-08-01

    Full Text Available Ammonia, an important basic chemical, is produced at a scale of 150 million tons per year. Half of hydrogen produced in chemical industry is used for ammonia production. Ammonia containing 17.5wt% hydrogen is an ideal carbon-free fuel for fuel cells. Compared to hydrogen, ammonia has many advantages. In this mini-review, the suitability of ammonia as fuel for fuel cells, the development of different types of fuel cells using ammonia as the fuel and the potential applications of ammonia fuel cells are briefly reviewed.

  8. Electrochemical Synthesis of Ammonia in Solid Electrolyte Cells

    Directory of Open Access Journals (Sweden)

    Ioannis eGaragounis

    2014-01-01

    Full Text Available Developed in the early 1900's, the Haber-Bosch synthesis is the dominant NH3 synthesis process. Parallel to catalyst optimization, current research efforts are also focused on the investigation of new methods for ammonia synthesis, including the electrochemical synthesis with the use of solid electrolyte cells. Since the first report on Solid State Ammonia Synthesis (SSAS, more than 30 solid electrolyte materials were tested and at least 15 catalysts were used as working electrodes. Thus far, the highest rate of ammonia formation reported is 1.13×10−8 mol s−1 cm−2, obtained at 80°C with a Nafion solid electrolyte and a mixed oxide, SmFe0.7Cu0.1Ni0.2O3, cathode. At high temperatures (>500oC the maximum rate was 9.5*10-9 mol s−1 cm−2 using Ce0.8Y0.2O2-δ -[Ca3(PO42 -K3PO4] as electrolyte and Ag-Pd as cathode. In this paper, the advantages and the disadvantages of SSAS vs the conventional process and the requirements that must be met in order to promote the electrochemical process into an industrial level, are discussed.

  9. Gas desorption properties of ammonia borane and metal hydride composites

    International Nuclear Information System (INIS)

    Matin, M.R.

    2009-01-01

    'Full text': Ammonia borane (NH 3 BH 3 ) has been of great interest owing to its ideal combination of low molecular weight and high H 2 storage capacity of 19.6 mass %, which exceeds the current capacity of gasoline. DOE's year 2015 targets involve gravimetric as well as volumetric energy densities. In this work, we have investigated thermal decomposition of ammonia borane and calcium hydride composites at different molar ratio. The samples were prepared by planetary ball milling under hydrogen gas atmosphere pressure of 1Mpa at room temperature for 2, and 10 hours. The gas desorption properties were examined by thermal desorption mass spectroscopy (TDMS). The identification of phases was carried out by X-ray diffraction. The results obtain were shown in fig (a),(b),and (c). Hydrogen desorption properties were observed at all molar ratios, but the desorption temperature is significantly lower at around 70 o C at molar ratio 1:1 as shown in fig (c), and unwanted gas (ammonia) emissions were remarkably suppressed by mixing with the calcium hydride. (author)

  10. Electrochemical Synthesis of Ammonia in Solid Electrolyte Cells

    International Nuclear Information System (INIS)

    Garagounis, Ioannis; Kyriakou, Vasileios; Skodra, Aglaia; Vasileiou, Eirini; Stoukides, Michael

    2014-01-01

    Developed in the early 1900s, the “Haber–Bosch” synthesis is the dominant NH 3 synthesis process. Parallel to catalyst optimization, current research efforts are also focused on the investigation of new methods for ammonia synthesis, including the electrochemical synthesis with the use of solid electrolyte cells. Since the first report on Solid State Ammonia Synthesis (SSAS), more than 30 solid electrolyte materials were tested and at least 15 catalysts were used as working electrodes. Thus far, the highest rate of ammonia formation reported is 1.13 × 10 -8 mol s -1 cm -2 , obtained at 80°C with a Nafion solid electrolyte and a mixed oxide, SmFe 0.7 Cu 0.1 Ni 0.2 O 3 , cathode. At high temperatures (>500°C), the maximum rate was 9.5 × 10 −9 mol s -1 cm -2 using Ce 0.8 Y 0.2 O 2-δ –[Ca 3 (PO 4 ) 2 –K 3 PO 4 ] as electrolyte and Ag–Pd as cathode. In this paper, the advantages and the disadvantages of SSAS vs. the conventional process and the requirements that must be met in order to promote the electrochemical process into an industrial level are discussed.

  11. Positron emission tomography of hepatic first-pass metabolism of ammonia in pig

    International Nuclear Information System (INIS)

    Keiding, S.; Munk, O.L.; Roelsgaard, K.; Bender, D.; Bass, L.

    2001-01-01

    Hepatic first-pass metabolism plays a key role in metabolic regulation and drug metabolism. Metabolic processes can be quantified in vivo by positron emission tomography scanning (PET). We wished to develop a PET technique to measure hepatic first-pass metabolism of ammonia. Seven anaesthetised pigs were given positron-labelled ammonia, 13 NH 3 , into the portal vein and into the vena cava as successive 2-min infusions followed by 22-min dynamic liver scanning. Vena cava infusion data were used to account for recirculation of tracer and metabolites following the portal vein infusion. The scan data were analysed by a model of sinusoidal zonation of ammonia metabolism with periportal urea formation and perivenous formation of glutamine. The hepatic extraction fraction of 13 NH 3 was 0.73±0.16 (mean±SD, n=7 pigs). Values of clearance of ammonia to urea and to glutamine were obtained, as were rate constants for washout of these two metabolites. Overall, the modelling showed half of the ammonia uptake to be converted to urea and half to glutamine. The washout rate constant for glutamine was about one-tenth of that for urea. We conclude that hepatic first-pass metabolism of ammonia was successfully assessed by PET. (orig.)

  12. Emergent macrophytes modify the abundance and community composition of ammonia oxidizers in their rhizosphere sediments.

    Science.gov (United States)

    Zhao, Dayong; He, Xiaowei; Huang, Rui; Yan, Wenming; Yu, Zhongbo

    2017-07-01

    Ammonia oxidation is a crucial process in global nitrogen cycling, which is catalyzed by the ammonia oxidizers. Emergent plants play important roles in the freshwater ecosystem. Therefore, it is meaningful to investigate the effects of emergent macrophytes on the abundance and community composition of ammonia oxidizers. In the present study, two commonly found emergent macrophytes (Zizania caduciflora and Phragmitas communis) were obtained from freshwater lakes and the abundance and community composition of the ammonia-oxidizing prokaryotes in the rhizosphere sediments of these emergent macrophytes were investigated. The abundance of the bacterial amoA gene was higher in the rhizosphere sediments of the emergent macrophytes than those of bulk sediments. Significant positive correlation was found between the potential nitrification rates (PNRs) and the abundance of bacterial amoA gene, suggesting that ammonia-oxidizing bacteria (AOB) might play an important role in the nitrification process of the rhizosphere sediments of emergent macrophytes. The Nitrosotalea cluster is the dominant ammonia-oxidizing archaea (AOA) group in all the sediment samples. Analysis of AOB group showed that the N. europaeal cluster dominated the rhizosphere sediments of Z. caduciflora and the bulk sediments, whereas the Nitrosospira cluster was the dominant AOB group in the rhizosphere sediments of P. communis. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Treating electrolytic manganese residue with alkaline additives for stabilizing manganese and removing ammonia

    International Nuclear Information System (INIS)

    Zhou, Changbo; Wang, Jiwei; Wang, Nanfang

    2013-01-01

    Electrolytic manganese residue (EMR) from the electrolytic manganese industry is a solid waste containing mainly calcium sulfate dihydrate and quartzite. It is impossible to directly use the EMR as a building material due to some contaminants such as soluble manganese, ammonia nitrogen and other toxic substances. To immobilize the contaminants and reduce their release into the environment, treating EMR using alkaline additives for stabilizing manganese and removing ammonia was investigated. The physical and chemical characteristics of the original EMR were characterized by XRFS, XRD, and SEM. Leaching test of the original EMR shows that the risks to the environment are the high content of soluble manganese and ammonia nitrogen. The influence of various alkaline additives, solidifying reaction time, and other solidifying reaction conditions such as outdoor ventilation and sunlight, and rain flow on the efficiencies of Mn 2+ solidification and ammonia nitrogen removal was investigated. The results show that with mass ratio of CaO to residue 1 : 8, when the solidifying reaction was carried out indoors for 4 h with no rain flow, the highest efficiencies of Mn 2+ solidification and ammonia nitrogen removal (99.98% and 99.21%) are obtained. Leaching test shows that the concentration and emission of manganese and ammonia nitrogen of the treated EMR meets the requirements of the Chinese government legislation (GB8978-1996)

  14. Modified Ammonia Removal Model Based on Equilibrium and Mass Transfer Principles

    International Nuclear Information System (INIS)

    Shanableh, A.; Imteaz, M.

    2010-01-01

    Yoon et al. 1 presented an approximate mathematical model to describe ammonia removal from an experimental batch reactor system with gaseous headspace. The development of the model was initially based on assuming instantaneous equilibrium between ammonia in the aqueous and gas phases. In the model, a 'saturation factor, β' was defined as a constant and used to check whether the equilibrium assumption was appropriate. The authors used the trends established by the estimated β values to conclude that the equilibrium assumption was not valid. The authors presented valuable experimental results obtained using a carefully designed system and the model used to analyze the results accounted for the following effects: speciation of ammonia between NH 3 and NH 4 + as a function of pH: temperature dependence of the reactions constants; and air flow rate. In this article, an alternative model based on the exact solution of the governing mass-balance differential equations was developed and used to describe ammonia removal without relying on the use of the saturation factor. The modified model was also extended to mathematically describe the pH dependence of the ammonia removal rate, in addition to accounting for the speciation of ammonia, temperature dependence of reactions constants, and air flow rate. The modified model was used to extend the analysis of the original experimental data presented by Yoon et al. 1 and the results matched the theory in an excellent manner

  15. Fabrication of interdigitated electrodes by inkjet printing technology for apllication in ammonia sensing

    International Nuclear Information System (INIS)

    Le, Duy Dam; Nguyen, Thi Ngoc Nhien; Doan, Duc Chanh Tin; Dang, Thi My Dung; Dang, Mau Chien

    2016-01-01

    In this paper interdigitated electrodes for gas sensors were fabricated by inkjet printing technology. Silver electrodes were inkjet printed on Si/SiO 2 substrates instead of traditional photolithography method. The inkjet printing parameters to obtain desired dimensions, thickness of the electrodes and distance between the interdigitated electrodes were optimized in this study. The fabricated interdigitated silver electrodes were tested for application in ammonia gas sensors. Conductive polyaniline (PANI) layer was coated on the silver interdigitated electrodes by drop-coating. Ammonia detection of the PANI-coated chips was characterized with a gas measurement system in which humidity and ammonia concentrations were well-controlled. The electrical conductivity of the PANI films coated on the electrodes was measured when the PANI films were exposed to nitrogen and ammonia. The conductivity of the PANI films decreased significantly due to the deprotonation process of PANI upon ammonia expodure. The recovery time was about 15 min by heating up the polymer chip at 60 °C. The results showed that the silver electrodes fabricated by inkjet printing technique could be used as a sensor platform for ammonia detection. (paper)

  16. Mono-fermentation of chicken manure: ammonia inhibition and recirculation of the digestate.

    Science.gov (United States)

    Nie, Hong; Jacobi, H Fabian; Strach, Katrin; Xu, Chunming; Zhou, Hongjun; Liebetrau, Jan

    2015-02-01

    The effects of ammonia concentration on the performance and stability of mono-fermentation of chicken manure were investigated in a lab-scale continuous stirred tank reactor at 40 °C. Technical stripping was performed to remove ammonia from the liquid fraction of digestate, and the entire product was recycled to the fermenter to control ammonia concentration in the fermenter. Organic loading rate (OLR) of 5.3 gVS/(L d) was achieved with an average free ammonia nitrogen (FAN) concentration of 0.77 g/L and a specific gas yield of 0.39 L/gVS. When OLR was increased to 6.0 gVS/(L d), stable operation could be obtained with an average FAN concentration of 0.86 g/L and a specific gas yield of 0.27 L/gVS. Mono-fermentation of chicken manure was successfully carried out at high ammonia concentrations. Controlled recirculation of treated liquid fraction of digestate could be a solution in large-scale application for both: to avoid ammonia inhibition and minimize digestate. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Aqueous-ammonia delignification of miscanthus followed by enzymatic hydrolysis to sugars.

    Science.gov (United States)

    Liu, Zhongguo; Padmanabhan, Sasisanker; Cheng, Kun; Schwyter, Philippe; Pauly, Markus; Bell, Alexis T; Prausnitz, John M

    2013-05-01

    This work concerns the effect of aqueous ammonia pretreatment at four temperatures and at 10, 20 or 30 wt.% ammonia. After 1h, more than 65% delignification is achieved at 150 or 180 °C for high and for low concentrations of ammonia. When the delignified miscanthus is enzymatically hydrolyzed for 96 h using cellulases and beta-glucosidase, conversion of the recovered solid to glucose is 53.4% and to xylose 70.0%. Additional glucose and xylose can be obtained from the ammonia-containing aqueous phase. Increased ammonia concentration leads to better conversion. Fourier-transform infrared and Two-dimensional (13)C-(1)H Heteronuclear Single Quantum Coherence (HSQC) Nuclear Magnetic Resonance spectroscopy provide data for the composition of the pretreated miscanthus and for that of the liquid extract. These spectra indicate that pretreatment with ammonia leads to de-acetylation of the xylan-backbone. The β-O-4' linked aryl ether remains the most abundant linkage in the pretreated miscanthus. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Aqueous Ammonia soaking of digested manure fibers

    DEFF Research Database (Denmark)

    Mirtsou-Xanthopoulou, Chrysoula; Jurado, Esperanza; Skiadas, Ioannis

    2012-01-01

    , their economical profitable operation relies on increasing the methane yield from manure, and especially of its solid fraction which is not so easily degradable. In the present study, Aqueous Ammonia Soaking was successfully applied on digested fibers separated from the effluent of a manure-fed, full......-scale anaerobic digester to enhance their methane productivity. Soaking in six different reagent concentrations in ammonia (5%, 10%, 15%, 20%, 25%, 32%) was applied for 3 days at 22°C. An overall methane yield increase from 85% to 110% was achieved compared to controls (digested manure fibers where AAS...... was not applied). The difference in reagent concentration at the range of 5-25% w/w in ammonia did not affect that much the overall methane yield resulting to an increase of 104-110% compared to the non AAS-treated fibers. Thus, an ammonia concentration as low as 5% is adequate for achieving the same increase...

  19. Ammonia Affects Astroglial Proliferation in Culture.

    Directory of Open Access Journals (Sweden)

    Guillermo Bodega

    Full Text Available Primary cultures of rat astroglial cells were exposed to 1, 3 and 5 mM NH4Cl for up to 10 days. Dose- and time-dependent reductions in cell numbers were seen, plus an increase in the proportion of cells in the S phase. The DNA content was reduced in the treated cells, and BrdU incorporation diminished. However, neither ammonia nor ammonia plus glutamine had any effect on DNA polymerase activity. iTRAQ analysis showed that exposure to ammonia induced a significant reduction in histone and heterochromatin protein 1 expression. A reduction in cell viability was also noted. The ammonia-induced reduction of proliferative activity in these cultured astroglial cells seems to be due to a delay in the completion of the S phase provoked by the inhibition of chromatin protein synthesis.

  20. Ammonia Affects Astroglial Proliferation in Culture

    Science.gov (United States)

    Bodega, Guillermo; Segura, Berta; Ciordia, Sergio; Mena, María del Carmen; López-Fernández, Luis Andrés; García, María Isabel; Trabado, Isabel; Suárez, Isabel

    2015-01-01

    Primary cultures of rat astroglial cells were exposed to 1, 3 and 5 mM NH4Cl for up to 10 days. Dose- and time-dependent reductions in cell numbers were seen, plus an increase in the proportion of cells in the S phase. The DNA content was reduced in the treated cells, and BrdU incorporation diminished. However, neither ammonia nor ammonia plus glutamine had any effect on DNA polymerase activity. iTRAQ analysis showed that exposure to ammonia induced a significant reduction in histone and heterochromatin protein 1 expression. A reduction in cell viability was also noted. The ammonia-induced reduction of proliferative activity in these cultured astroglial cells seems to be due to a delay in the completion of the S phase provoked by the inhibition of chromatin protein synthesis. PMID:26421615

  1. DIRECT AMMONIA-AIR FUEL CELL.

    Science.gov (United States)

    A new type of direct oxidation ammonia fuel cell was investigated. This cell is based on the use of a non-aqueous fused hydroxide electrolyte matrix...EMF’s of 0.5 to 0.6 volts. At practical levels of current density the direct ammonia fuel cell has an overall efficiency of about 60% compared to 30-35% for the indirect-type fuel cell . (Author)

  2. Nitrocarburizing in ammonia-hydrocarbon gas mixtures

    DEFF Research Database (Denmark)

    Pedersen, Hanne; Christiansen, Thomas; Somers, Marcel A. J.

    2011-01-01

    The present work investigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammonia-propene-hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere...... microscopy and X-ray diffraction analysis. It is shown that the use of unsaturated hydrocarbon gas in nitrocarburising processes is a viable alternative to traditional nitrocarburising methods....

  3. Study of the acceleration of ammonia generation process from poultry residues aiming at hydrogen production

    International Nuclear Information System (INIS)

    Egute, Nayara dos Santos

    2010-01-01

    The hydrogen, utilized in fuel cells, can be produced from a variety of intermediate chemicals, between them, the ammonia. The ammonia gas as a raw material for the hydrogen production has been used due to its high energetic content, facility of decomposition, high availability, low prices, low storage pressure and its by-products are environmentally correct. One of the sources of ammonia is poultry and egg production systems. In these systems the ammonia is produced from the decomposition of uric acid present in the excreta of birds. The residue from the poultry-rearing farms is the broiler litter and from the egg production system is the excreta without any substrate. The characterization of these residues was performed using the Wavelength-Dispersive X-Ray Fluorescence (WDXRF), Elementary Analysis (CHN), Thermogravimetry and GC/MS - Gas chromatography/ Mass spectrometry. The studied factors which influence the ammonia volatilization were: nitrogen content, raising period, urease enzyme, temperature, pH and moisture content. The experiment results with poultry litter and excreta allow to conclude that the manipulation of the following parameters increased the ammonia emission: pH, nitrogen content, raising period, age of birds and excreta accumulation, urease enzyme and the temperature. The addition of different amounts of sand in the excreta and different volumes of water in the poultry litter inhibited the emission of ammonia. The variation of the quantity of material (broiler litter or excreta) and the volume of the flask used as incubator chamber showed no significant alterations to be chosen as a variable. The excreta was considered more appropriate than poultry litter for the objectives of this work due to the higher ammonia concentrations determined in this material. Due to the large amount of poultry litter and excreta from the production processes, the reuse of poultry residues to obtain ammonia is necessary to improve the quality of the local

  4. A process-based model for ammonia emission from urine patches, GAG (Generation of Ammonia from Grazing): description and sensitivity analysis

    DEFF Research Database (Denmark)

    Móring, Andrea; Vieno, Massimo; M. Doherty, Ruth

    2016-01-01

    In this paper a new process-based, weather-driven model for ammonia (NH3) emission from a urine patch has been developed and its sensitivity to various factors assessed. The GAG model (Generation of Ammonia from Grazing) is capable of simulating the TAN (total ammoniacal nitrogen) and the water...... and may depend on interactions with other nitrogen cycling processes. In addition, we found that wind speed and relative humidity are also significant influencing factors. Considering that all the input parameters can be obtained for larger scales, GAG is potentially suitable for field and regional scale...

  5. Corrosion inhibitor for aqueous ammonia absorption system

    Science.gov (United States)

    Phillips, B.A.; Whitlow, E.P.

    1998-09-22

    A method is described for inhibiting corrosion and the formation of hydrogen and thus improving absorption in an ammonia/water absorption refrigeration, air conditioning or heat pump system by maintaining the hydroxyl ion concentration of the aqueous ammonia working fluid within a selected range under anaerobic conditions at temperatures up to 425 F. This hydroxyl ion concentration is maintained by introducing to the aqueous ammonia working fluid an inhibitor in an amount effective to produce a hydroxyl ion concentration corresponding to a normality of the inhibitor relative to the water content ranging from about 0.015 N to about 0.2 N at 25 C. Also, working fluids for inhibiting the corrosion of carbon steel and resulting hydrogen formation and improving absorption in an ammonia/water absorption system under anaerobic conditions at up to 425 F. The working fluids may be aqueous solutions of ammonia and a strong base or aqueous solutions of ammonia, a strong base, and a specified buffer. 5 figs.

  6. Determination of Energy Fluxes Over Agricultural Surfaces

    Directory of Open Access Journals (Sweden)

    Josefina Argete

    1994-12-01

    Full Text Available An energy budget was conducted over two kinds if surfaces: grass and corn canopy. The net radiative flux and the soil heat flux were directly measured while the latent and sensible heat flux were calculated from the vertical profiles if wet and dry-bulb temperature and wind speed. The crop storage flux was also estimated. Using the gradient or aerodynamic equations, the calculated fluxes when compared to the measured fluxes in the context of an energy budget gave an SEE = 63 Wm-2 over grass and SEE = 81 Wm-2 over corn canopy. The calculated fluxes compared reasonably well with those obtained using the Penman equations.For an energy budget research with limited instrumentation, the aerodynamic method performed satisfactorily in estimating the daytime fluxes, when atmospheric conditions are fully convective, but failed when conditions were stably stratified as during nighttime.

  7. Ammonia removal in the carbon contactor of a hybrid membrane process.

    Science.gov (United States)

    Stoquart, Céline; Servais, Pierre; Barbeau, Benoit

    2014-12-15

    The hybrid membrane process (HMP) coupling powdered activated carbon (PAC) and low-pressure membrane filtration is emerging as a promising new option to remove dissolved contaminants from drinking water. Yet, defining optimal HMP operating conditions has not been confirmed. In this study, ammonia removal occurring in the PAC contactor of an HMP was simulated at lab-scale. Kinetics were monitored using three PAC concentrations (1-5-10 g L(-1)), three PAC ages (0-10-60 days), two temperatures (7-22 °C), in ambient influent condition (100 μg N-NH4 L(-1)) as well as with a simulated peak pollution scenario (1000 μg N-NH4L(-1)). The following conclusions were drawn: i) Using a colonized PAC in the HMP is essential to reach complete ammonia removal, ii) an older PAC offers a higher resilience to temperature decrease as well as lower operating costs; ii) PAC concentration inside the HMP reactor is not a key operating parameter as under the conditions tested, PAC colonization was not limited by the available surface; iii) ammonia flux limited biomass growth and iv) hydraulic retention time was a critical parameter. In the case of a peak pollution, the process was most probably phosphate-limited but a mixed adsorption/nitrification still allowed reaching a 50% ammonia removal. Finally, a kinetic model based on these experiments is proposed to predict ammonia removal occurring in the PAC reactor of the HMP. The model determines the relative importance of the adsorption and biological oxidation of ammonia on colonized PAC, and demonstrates the combined role of nitrification and residual adsorption capacity of colonized PAC. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Impact of Anaerobic Digestion of Liquid Dairy Manure on Ammonia Volatilization Process

    Science.gov (United States)

    Koirala, K.

    2013-12-01

    The goal of this study was to determine the effect of anaerobic digestion (AD) on the mechanism of ammonia volatilization from liquid dairy manure, in storage or treatment lagoon, prior to land application. Physical-chemical properties of liquid dairy manure, which may affect ammonia volatilization process, were determined before and after AD. The properties of interest included: particle size distribution (PSD), total solids (TS), volatile solids (VS), viscosity, pH, total ammoniacal nitrogen (TAN), and ionic strength (IS). The overall mass transfer coefficient of ammonia (KoL) and the NH3 fraction of TAN (β) for the undigested (UD) and AD manures were then experimentally determined in a laboratory convective emission chamber (CEC) at a constant wind speed of 1.5 m s-1 and fixed air temperature of 25 °C at liquid manure temperatures of 15, 25, and 35 °C. The PSD indicated non-normal left skewed distribution for both AD and UD manures particles, suggestive of heavier concentrations of particles towards the lower particle size range. The volume median diameters (VMD) for solids from UD and AD were not significantly different (p= 0.65), but the geometric standard deviations (GSD) were significantly different (p = 0.001), indicating slightly larger particles but more widely distributed solids in UD than AD manure. Results also indicated significantly higher pH, TAN, ionic strength (IS) and viscosity in AD manure. The KoL and β for AD manure determined under identical conditions (air temperature, liquid temperature, and airflow) were significantly higher (p > 0.05) than for UD manure. Overall, these findings suggest that AD of dairy manure significantly increased initial ammonia volatilization potential from liquid dairy manure; with the largest increase (~62%) emanating from increased ammonium dissociation. The initial flux of ammonia, during the experiment period, was ~84% more from AD than in UD dairy manure. Keywords. Process based models, mass transfer

  9. Effects of chronic ammonia exposure on ammonia metabolism and excretion in marine medaka Oryzias melastigma.

    Science.gov (United States)

    Gao, Na; Zhu, Limei; Guo, Zhiqiang; Yi, Meisheng; Zhang, Li

    2017-06-01

    Ammonia is highly toxic to aquatic organisms, but whether ammonia excretion or ammonia metabolism to less toxic compounds is the major strategy for detoxification in marine fish against chronic ammonia exposure is unclear to date. In this study, we investigated the metabolism and excretion of ammonia in marine medaka Oryzias melastigma during chronic ammonia exposure. The fish were exposed to 0, 0.1, 0.3, 0.6, and 1.1 mmol l -1  NH 4 Cl spiked seawater for 8 weeks. Exposure of 0.3-1.1 mmol l -1  NH 4 Cl had deleterious effects on the fish, including significant reductions in growth, feed intake, and total protein content. However, the fish could take strategies to detoxify ammonia. The tissue ammonia (T Amm ) in the 0.3-1.1 mmol l -1  NH 4 Cl treatments was significantly higher than those in the 0 and 0.1 mmol l -1  NH 4 Cl treatments after 2 weeks of exposure, but it recovered with prolonged exposure time, ultimately reaching the control level after 8 weeks. The amino acid catabolic rate decreased to reduce the gross ammonia production with the increasing ambient ammonia concentration. The concentrations of most metabolites remained constant in the 0-0.6 mmol l -1  NH 4 Cl treatments, whereas 5 amino acids and 3 energy metabolism-related metabolites decreased in the 1.1 mmol l -1  NH 4 Cl treatment. J Amm steadily increased in ambient ammonia from 0 to 0.6 mmol l -1 and slightly decreased when the ambient ammonia concentration increased to 1.1 mmol l -1 . Overall, marine medaka cope with sublethal ammonia environment by regulating the tissue T Amm via reducing the ammonia production and increasing ammonia excretion. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Intestinal ammonia transport in freshwater and seawater acclimated rainbow trout (Oncorhynchus mykiss): evidence for a Na+ coupled uptake mechanism.

    Science.gov (United States)

    Rubino, Julian G; Zimmer, Alex M; Wood, Chris M

    2015-05-01

    In vitro gut sac experiments were performed on freshwater and 60% seawater acclimated trout (Oncorhynchus mykiss) under treatments designed to discern possible mechanisms of intestinal ammonia transport. Seawater acclimation increased ammonia flux rate into the serosal saline (Jsamm) in the anterior intestine, however it did not alter Jsamm in the mid- or posterior intestine suggesting similar mechanisms of ammonia handling in freshwater and seawater fish. Both fluid transport rate (FTR) and Jsamm were inhibited in response to basolateral ouabain treatment, suggesting a linkage of ammonia uptake to active transport, possibly coupled to fluid transport processes via solvent drag. Furthermore, decreases in FTR and Jsamm caused by low Na(+) treatment indicated a Na(+) linked transport mechanism. Mucosal bumetanide (10(-4) M) had no impact on FTR, yet decreased Jsamm in the anterior and mid-intestine, suggesting NH4(+) substitution for K(+) on an apical NKCC, and at least a partial uncoupling of ammonia transport from fluid transport. Additional treatments (amiloride, 5-(N-ethyl-N-isopropyl)amiloride (EIPA), phenamil, bafilomycin, 4',6-diamidino-2-phenylindole (DAPI), high sodium) intended to disrupt alternative routes of Na(+) uptake yielded no change in FTR or Jsamm, suggesting the absence of direct competition between Na(+) and ammonia for transport. Finally, [(14)C]methylamine permeability (PMA) measurements indicated the likely presence of an intestinal Rh-mediated ammonia transport system, as increasing NH4Cl (0, 1, 5 mmol l(-1)) concentrations reduced PMA, suggesting competition for transport through Rh proteins. Overall, the data presented in this paper provide some of the first insights into mechanisms of teleost intestinal ammonia transport. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Fluorescence Excitation Models of Ammonia and Amidogen Radical (NH2) in Comets: Application to Comet C/2004 Q2 (Machholz)

    Science.gov (United States)

    Kawakita, Hideyo; Mumma, Michael J.

    2011-01-01

    Ammonia is a major reservoir of nitrogen atoms in cometary materials. However, detections of ammonia in comets are rare, with several achieved at radio wavelengths. A few more detections were obtained through near-infrared observations (around the 3 m wavelength region), but moderate relative velocity shifts are required to separate emission lines of cometary ammonia from telluric absorption lines in the 3 micron wavelength region. On the other hand, the amidogen radical (NH2 -- a photodissociation product of ammonia in the coma) also shows rovibrational emission lines in the 3 micron wavelength region. Thus, gas production rates for ammonia can be determined from the rovibrational emission lines of ammonia (directly) and amidogen radical (indirectly) simultaneously in the near-infrared. In this article, we present new fluorescence excitation models for cometary ammonia and amidogen radical in the near-infrared, and we apply these models to the near-infrared high-dispersion spectra of comet C/2004 Q2 (Machholz) to determine the mixing ratio of ammonia to water in the comet. Based on direct detection of NH3 lines, the mixing ratio of NH3/H2O is 0.46% +/- 0.03% in C/2004 Q2 (Machholz), in agreement with other results. The mixing ratio of ammonia determined from the NH2 observations (0.31% -- 0.79%) is consistent but has relatively larger error, owing to uncertainty in the photodissociation rates of ammonia. At the present level of accuracy, we confirm that NH3 could be the sole parent of NH2 in this comet.

  12. FLUORESCENCE EXCITATION MODELS OF AMMONIA AND AMIDOGEN RADICAL (NH2) IN COMETS: APPLICATION TO COMET C/2004 Q2 (MACHHOLZ)

    International Nuclear Information System (INIS)

    Kawakita, Hideyo; Mumma, Michael J.

    2011-01-01

    Ammonia is a major reservoir of nitrogen atoms in cometary materials. However, detections of ammonia in comets are rare, with several achieved at radio wavelengths. A few more detections were obtained through near-infrared observations (around the 3 μm wavelength region), but moderate relative velocity shifts are required to separate emission lines of cometary ammonia from telluric absorption lines in the 3 μm wavelength region. On the other hand, the amidogen radical (NH 2 -a photodissociation product of ammonia in the coma) also shows rovibrational emission lines in the 3 μm wavelength region. Thus, gas production rates for ammonia can be determined from the rovibrational emission lines of ammonia (directly) and amidogen radical (indirectly) simultaneously in the near-infrared. In this article, we present new fluorescence excitation models for cometary ammonia and amidogen radical in the near-infrared, and we apply these models to the near-infrared high-dispersion spectra of comet C/2004 Q2 (Machholz) to determine the mixing ratio of ammonia to water in the comet. Based on direct detection of NH 3 lines, the mixing ratio of NH 3 /H 2 O is 0.46% ± 0.03% in C/2004 Q2 (Machholz), in agreement with other results. The mixing ratio of ammonia determined from the NH 2 observations (0.31%-0.79%) is consistent but has relatively larger error, owing to uncertainty in the photodissociation rates of ammonia. At the present level of accuracy, we confirm that NH 3 could be the sole parent of NH 2 in this comet.

  13. The story of the ammonia molecule: Ten years of investigation of molecular inversion

    Science.gov (United States)

    Papoušek, Dušan

    1983-07-01

    The application of the Hougen-Bunker-Johns (HBJ) Hamiltonian to quasiplanar molecules is discussed with special emphasis on ammonia. The double-minimum potential functions of ammonia obtained in the approximation of the rigid invertor, "harmonic" nonrigid invertor, and "anharmonic" nonrigid invertor are compared from the point of view of their isotopic invariancy. The HBJ Hamiltonian can also be applied with advantage to the quantitative analysis of the transition frequencies obtained by high and very high resolution spectroscopy, as well as to the interpretation of the anomalous inversional dependence of the dipole moment function, quadrupole coupling or of the g-tensor function. The newly determined "true" barrier height for ammonia inversion by fitting the experimental data on vibration-inversion-rotation transitions is 1834 cm -1.

  14. Surface–atmosphere exchange of ammonia over peatland using QCL-based eddy-covariance measurements and inferential modeling

    Directory of Open Access Journals (Sweden)

    U. Zöll

    2016-09-01

    Full Text Available Recent advances in laser spectrometry offer new opportunities to investigate ecosystem–atmosphere exchange of environmentally relevant trace gases. In this study, we demonstrate the applicability of a quantum cascade laser (QCL absorption spectrometer to continuously measure ammonia concentrations at high time resolution and thus to quantify the net exchange between a seminatural peatland ecosystem and the atmosphere based on the eddy-covariance approach. Changing diurnal patterns of both ammonia concentration and fluxes were found during different periods of the campaign. We observed a clear tipping point in early spring with decreasing ammonia deposition velocities and increasingly bidirectional fluxes that occurred after the switch from dormant vegetation to CO2 uptake but was triggered by a significant weather change. While several biophysical parameters such as temperature, radiation, and surface wetness were identified to partially regulate ammonia exchange at the site, the seasonal concentration pattern was clearly dominated by agricultural practices in the surrounding area. Comparing the results of a compensation point model with our measurement-based flux estimates showed considerable differences in some periods of the campaign due to overestimation of non-stomatal resistances caused by low acid ratios. The total cumulative campaign exchange of ammonia after 9 weeks, however, differed only in a 6 % deviation with 911 and 857 g NH3-N ha−1 deposition being found by measurements and modeling, respectively. Extrapolating our findings to an entire year, ammonia deposition was lower than reported by Hurkuck et al. (2014 for the same site in previous years using denuder systems. This was likely due to a better representation of the emission component in the net signal of eddy-covariance fluxes as well as better adapted site-specific parameters in the model. Our study not only stresses the importance of high-quality measurements

  15. Is there in vivo evidence for amino acid shuttles carrying ammonia from neurons to astrocytes?

    Science.gov (United States)

    Rothman, Douglas L; De Feyter, Henk M; Maciejewski, Paul K; Behar, Kevin L

    2012-11-01

    The high in vivo flux of the glutamate/glutamine cycle puts a strong demand on the return of ammonia released by phosphate activated glutaminase from the neurons to the astrocytes in order to maintain nitrogen balance. In this paper we review several amino acid shuttles that have been proposed for balancing the nitrogen flows between neurons and astrocytes in the glutamate/glutamine cycle. All of these cycles depend on the directionality of glutamate dehydrogenase, catalyzing reductive glutamate synthesis (forward reaction) in the neuron in order to capture the ammonia released by phosphate activated glutaminase, while catalyzing oxidative deamination of glutamate (reverse reaction) in the astrocytes to release ammonia for glutamine synthesis. Reanalysis of results from in vivo experiments using (13)N and (15)N labeled ammonia and (15)N leucine in rats suggests that the maximum flux of the alanine/lactate or branched chain amino acid/branched chain amino acid transaminase shuttles between neurons and astrocytes are approximately 3-5 times lower than would be required to account for the ammonia transfer from neurons to astrocytes needed for glutamine synthesis (amide nitrogen) to sustain the glutamate/glutamine cycle. However, in the rat brain both the total ammonia fixation rate by glutamate dehydrogenase and the total branched chain amino acid transaminase activity are sufficient to support a branched chain amino acid/branched chain keto acid shuttle, as proposed by Hutson and coworkers, which would support the de novo synthesis of glutamine in the astrocyte to replace the ~20 % of neurotransmitter glutamate that is oxidized. A higher fraction of the nitrogen needs of total glutamate neurotransmitter cycling could be supported by hybrid cycles in which glutamate and tricarboxylic acid cycle intermediates act as a nitrogen shuttle. A limitation of all in vivo studies in animals conducted to date is that none have shown transfer of nitrogen for glutamine amide

  16. Carbonation of residual brines produced by ammonia-soda process

    Science.gov (United States)

    Filippova, I. V.; Piriou, P.; Filippov, L. O.; Yvon, J.; Grandjean, M.

    2013-03-01

    This work deals with the carbonation of residual brines produced during the manufacture of soda ash to avoid the unsuitable phase transformation during the land storage. The study resulted in a demonstration pilot, which showed the feasibility of such an approach and the possibility of his extension to an industrial scale. Carbonation of the residual brines is a promising process as it entirely transforms Ca(OH)2, "CaOHCl" and CSH into calcite, avoids the further phase evolution, allows to obtain a neutral pH which considerably reduce the land storage impact on environment and shorten by around 10 % the global CO2 emission of the ammonia-soda process.

  17. Ammonia tolerant enriched methanogenic cultures as bioaugmentation inocula to alleviate ammonia inhibition in continuous anaerobic reactors

    DEFF Research Database (Denmark)

    Fotidis, Ioannis; Wang, Han; Angelidaki, Irini

    Ammonia is the most common inhibitor of anaerobic digestion (AD) process, resulting in suboptimal exploitation of the biogas potential of the feedstocks, causing significant economic losses to the biogas plants. Ammonia is mainly inhibiting the aceticlastic methanogens, while the hydrogenotrophic...... methanogens are more robust to ammonia toxicity effect. It has been shown that bioaugmentation of a pure strain of a hydrogenotrophic methanogen (i.e. Methanoculleus bourgensis) in an ammonia inhibited continuous anaerobic reactor can improve methane production more than 30%. Nevertheless, cultivation...... of a pure culture, to be used as bioaugmentation inoculum, poses technical difficulties due to the required sterile conditions and the special growing media. On the contrary acclimatized enrichment methanogenic cultures have lower requirements to sterility. In the present study, we used an enriched ammonia...

  18. Phase behaviour and thermoelastic properties of ammonia hydrate and ice polymorphs from 0 - 2 GPa

    Science.gov (United States)

    Fortes, A. D.; Wood, I. G.; Vocadlo, L.

    2008-12-01

    growth kinetics of the high-pressure ammonia dihydrate, ammonia monohydrate and ice polymorphs obtained from our data.

  19. Ammonia stripping of biologically treated liquid manure.

    Science.gov (United States)

    Alitalo, Anni; Kyrö, Aleksis; Aura, Erkki

    2012-01-01

    A prerequisite for efficient ammonia removal in air stripping is that the pH of the liquid to be stripped is sufficiently high. Swine manure pH is usually around 7. At pH 7 (at 20°C), only 0.4% of ammonium is in ammonia form, and it is necessary to raise the pH of swine slurry to achieve efficient ammonia removal. Because manure has a very high buffering capacity, large amounts of chemicals are needed to change the slurry pH. The present study showed that efficient air stripping of manure can be achieved with a small amount of chemicals and without strong bases like NaOH. Slurry was subjected to aerobic biological treatment to raise pH before stripping. This facilitated 8 to 32% ammonia removal without chemical treatment. The slurry was further subjected to repeated cycles of stripping with MgO and Ca(OH)(2) additions after the first and second strippings, respectively, to raise slurry pH in between the stripping cycles. After three consecutive stripping cycles, 59 to 86% of the original ammonium had been removed. It was shown that the reduction in buffer capacity of the slurry was due to ammonia and carbonate removal during the stripping cycles. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  20. Study of Ammonia Emissions in a Ventilated Pig Pen

    DEFF Research Database (Denmark)

    Rong, Li

    Pig productions cause a wide emission of odors, such as ammonia (NH3), hydrogen sulfide (H2S), and methane (CH4). Ammonia is one of the most important emissions for evaluating the air quality either in animal buildings or atmospheric environment. In studies of ammonia emission from animal buildings...... reported in literature, little effort has been made to investigate the accuracy of current Henry’s law constant for modeling ammonia mass transfer process and study ammonia emissions in a full scale pig pen from fluid dynamics by CFD simulations. This will be the main objectives of this study. The ammonia...

  1. Nitrifying Community Analysis in a Single Submerged Attached-Growth Bioreactor for Treatment of High-Ammonia Waste Stream

    DEFF Research Database (Denmark)

    Gu, April Z.; Pedros, Philip B; Kristiansen, Anja

    2007-01-01

    addition (methanol). With influent ammonia and total Kjeldahl nitrogen ranging from 537 to 968 mg/L and 643 to1510 mg/L, respectively, 85% nitrogen removal was obtained, and effluent was dominated by nitrite (NO2 −/NOx >0.95). Nitrifying community analysis using fluorescence in situ hybridization (FISH...... in this study is applicable for high-ammonia-strength wastewater treatment, such as centrate or industrial wastes. Udgivelsesdato: December 2007...

  2. Effect of dietary protein restriction on renal ammonia metabolism

    Science.gov (United States)

    Lee, Hyun-Wook; Osis, Gunars; Handlogten, Mary E.; Guo, Hui; Verlander, Jill W.

    2015-01-01

    Dietary protein restriction has multiple benefits in kidney disease. Because protein intake is a major determinant of endogenous acid production, it is important that net acid excretion change in parallel during protein restriction. Ammonia is the primary component of net acid excretion, and inappropriate ammonia excretion can lead to negative nitrogen balance. Accordingly, we examined ammonia excretion in response to protein restriction and then we determined the molecular mechanism of the changes observed. Wild-type C57Bl/6 mice fed a 20% protein diet and then changed to 6% protein developed an 85% reduction in ammonia excretion within 2 days, which persisted during a 10-day study. The expression of multiple proteins involved in renal ammonia metabolism was altered, including the ammonia-generating enzymes phosphate-dependent glutaminase (PDG) and phosphoenolpyruvate carboxykinase (PEPCK) and the ammonia-metabolizing enzyme glutamine synthetase. Rhbg, an ammonia transporter, increased in expression in the inner stripe of outer medullary collecting duct intercalated cell (OMCDis-IC). However, collecting duct-specific Rhbg deletion did not alter the response to protein restriction. Rhcg deletion did not alter ammonia excretion in response to dietary protein restriction. These results indicate 1) dietary protein restriction decreases renal ammonia excretion through coordinated regulation of multiple components of ammonia metabolism; 2) increased Rhbg expression in the OMCDis-IC may indicate a biological role in addition to ammonia transport; and 3) Rhcg expression is not necessary to decrease ammonia excretion during dietary protein restriction. PMID:25925252

  3. Enrichment of high ammonia tolerant methanogenic culture

    DEFF Research Database (Denmark)

    Fotidis, Ioannis; Karakashev, Dimitar Borisov; Proietti, Nicolas

    Ammonia is the major toxicant in full scale anaerobic digesters of animal wastes which are rich in proteins and/or urea, such as pig or poultry wastes. Ammonia inhibition decreases methane production rates, increases volatile fatty acids concentration and leads to economic losses for the biogas...... was derived from a full scale biogas reactor (Hashøj, Denmark), fed with 75% animal manure and 25% food industries organic waste. Basal anaerobic medium was used for the enrichment along with sodium acetate (1 g HAc L-1) as a carbon source. Fluorescence insitu hybridization (FISH) was used to determine...... microbial community composition. The outcome of the enrichment process was a mesophilic aceticlastic methanogenic enriched culture able to withstand high ammonia loads and utilize acetate and form methane stoichiometrically. FISH analysis showed that the methanogens of the enriched culture belonged...

  4. Nitrogen removal from digested slurries using a simplified ammonia stripping technique.

    Science.gov (United States)

    Provolo, Giorgio; Perazzolo, Francesca; Mattachini, Gabriele; Finzi, Alberto; Naldi, Ezio; Riva, Elisabetta

    2017-11-01

    This study assessed a novel technique for removing nitrogen from digested organic waste based on a slow release of ammonia that was promoted by continuous mixing of the digestate and delivering a continuous air stream across the surface of the liquid. Three 10-day experiments were conducted using two 50-L reactors. In the first two, nitrogen removal efficiencies were evaluated from identical digestates maintained at different temperatures (30°C and 40°C). At the start of the first experiment, the digestates were adjusted to pH 9 using sodium hydroxide, while in the second experiment pH was not adjusted. The highest ammonia removal efficiency (87%) was obtained at 40°C with pH adjustment. However at 40°C without pH adjustment, removal efficiencies of 69% for ammonia and 47% for total nitrogen were obtained. In the third experiment two different digestates were tested at 50°C without pH adjustment. Although the initial chemical characteristics of the digestates were different in this experiment, the ammonia removal efficiencies were very similar (approximately 85%). Despite ammonia removal, the pH increased in all experiments, most likely due to carbon dioxide stripping that was promoted by temperature and mixing. The technique proved to be suitable for removing nitrogen following anaerobic digestion of livestock manure because effective removal was obtained at natural pH (≈8) and 40°C, common operating conditions at typical biogas plants that process manure. Furthermore, the electrical energy requirement to operate the process is limited (estimated to be 3.8kWhm -3 digestate). Further improvements may increase the efficiency and reduce the processing time of this treatment technique. Even without these advances slow-rate air stripping of ammonia is a viable option for reducing the environmental impact associated with animal manure management. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Ammonia emission time profiles based on manure transport data improve ammonia modelling across north western Europe

    Science.gov (United States)

    Hendriks, C.; Kranenburg, R.; Kuenen, J. J. P.; Van den Bril, B.; Verguts, V.; Schaap, M.

    2016-04-01

    Accurate modelling of mitigation measures for nitrogen deposition and secondary inorganic aerosol (SIA) episodes requires a detailed representation of emission patterns from agriculture. In this study the meteorological influence on the temporal variability of ammonia emissions from livestock housing and application of manure and fertilizer are included in the chemistry transport model LOTOS-EUROS. For manure application, manure transport data from Flanders (Belgium) were used as a proxy to derive the emission variability. Using improved ammonia emission variability strongly improves model performance for ammonia, mainly by a better representation of the spring maximum. The impact on model performance for SIA was negligible as explained by the limited, ammonia rich region in which the emission variability was updated. The contribution of Flemish agriculture to modelled annual mean ammonia and SIA concentrations in Flanders were quantified at respectively 7-8 and 1-2 μg/m3. A scenario study was performed to investigate the effects of reducing ammonia emissions from manure application during PM episodes by 75%, yielding a maximum reduction in modelled SIA levels of 1-3 μg/m3 during episodes. Year-to-year emission variability and a soil module to explicitly model the emission process from manure and fertilizer application are needed to further improve the modelling of the ammonia budget.

  6. Simulation Of Aqua-Ammonia Refrigeration System Using The Cape-Open To Cape-Open COCO Simulator

    Directory of Open Access Journals (Sweden)

    Janavi Gohil

    2017-03-01

    Full Text Available In this paper we have simulated a flow sheet of aqua ammonia refrigeration system using Cape Open simulator. The main aim of writing this paper is to compare the results obtained from thermodynamic simulation of aqua ammonia refrigeration system and the results obtained from the flow sheet simulation in Cape-Open to Cape-Open COCO simulator. The corresponding COP values obtained from both the sources are calculated and compared. With the error being very minute the calculations using simulator prove to be more efficient and timesaving when compared to the results obtained by calculations done using tedious thermodynamic simulations and constant mass balance for different process conditions.

  7. Implementação computacional do modelo carga-fluxo de carga-fluxo de dipolo para cálculo e interpretação das intensidades do espectro infravermelho Computational implementation of the model charge-charge flux-dipole flux for calculation and analysis of infrared intensities

    Directory of Open Access Journals (Sweden)

    Thiago C. F. Gomes

    2008-01-01

    Full Text Available The first computational implementation that automates the procedures involved in the calculation of infrared intensities using the charge-charge flux-dipole flux model is presented. The atomic charges and dipoles from the Quantum Theory of Atoms in Molecules (QTAIM model was programmed for Morphy98, Gaussian98 and Gaussian03 programs outputs, but for the ChelpG parameters only the Gaussian programs are supported. Results of illustrative but new calculations for the water, ammonia and methane molecules at the MP2/6-311++G(3d,3p theoretical level, using the ChelpG and QTAIM/Morphy charges and dipoles are presented. These results showed excellent agreement with analytical results obtained directly at the MP2/6-311++G(3d,3p level of theory.

  8. Modelling of Ammonia Heat Pump Desuperheaters

    DEFF Research Database (Denmark)

    Christensen, Stefan Wuust; Elmegaard, Brian; Markussen, Wiebke Brix

    2015-01-01

    This paper presents a study of modelling desuperheating in ammonia heat pumps. Focus is on the temperature profile of the superheated refrigerant. Typically, the surface area of a heat exchanger is estimated using the Log Mean Temperature Difference (LMTD) method. The assumption of this method...... is that the specific heat is constant throughout the temperature glide of the refrigerant in the heat exchanger. However, considering ammonia as refrigerant, the LMTD method does not give accurate results due to significant variations of the specific heat. By comparing the actual temperature profiles from a one...

  9. Biochemistry of Ammonia Monoxygenase from Nitrosomonas

    Energy Technology Data Exchange (ETDEWEB)

    Alan Hooper

    2009-07-15

    Major results. 1. CytochromecM552, a protein in the electron transfer chain to ammonia monooxygenase. Purification, modeling of protein structure based on primary structure, characterization of 4 hemes by magnetic spectroscopy, potentiometry, ligand binding and turnover. Kim, H. J., ,Zatsman, et al. 2008). 2. Characterization of proteins which thought to be involved in the AMO reaction or to protect AMO from toxic nitrogenous intermediates such as NO. Nitrosocyanin is a protein present only in bacteria which catalyze the ammonia monoxygenase reaction (1). Cytochrome c P460 beta and cytochrome c’ beta.

  10. Electrochemical ammonia production on molybdenum nitride nanoclusters

    DEFF Research Database (Denmark)

    Howalt, Jakob Geelmuyden; Vegge, Tejs

    2013-01-01

    Theoretical investigations of electrochemical production of ammonia at ambient temperature and pressure on nitrogen covered molybdenum nanoparticles are presented. Density functional theory calculations are used in combination with the computational hydrogen electrode approach to calculate the free...... energy profile for electrochemical protonation of N2 and N adatoms on cuboctahedral Mo13 nanoparticles. Pathways for electrochemical ammonia production via direct protonation of N adatoms and N2 admolecules with an onset potential as low as -0.5 V and generally lower than -0.8 V on both a nitrogen...

  11. Recovery of ammonia and sulfate from waste streams and bioenergy production via bipolar bioelectrodialysis

    DEFF Research Database (Denmark)

    Zhang, Yifeng; Angelidaki, Irini

    2015-01-01

    Ammonia and sulfate, which are prevalent pollutants in agricultural and industrial wastewaters, can cause serious inhibition in several biological treatment processes, such as anaerobic digestion. In this study, a novel bioelectrochemical approach termed bipolar bioelectrodialysis was developed...... to recover ammonia and sulfate from waste streams and thereby counteracting their toxicity during anaerobic digestion. Furthermore, hydrogen production and wastewater treatment were also accomplished. At an applied voltage of 1.2 V, nitrogen and sulfate fluxes of 5.1 g View the MathML sourceNH4+-N/m2/d...... bioelectrodialysis was successfully demonstrated with cattle manure. The results provide new possibilities for development of cost-effective technologies, capable of waste resources recovery and renewable energy production....

  12. Solid solution barium–strontium chlorides with tunable ammonia desorption properties and superior storage capacity

    DEFF Research Database (Denmark)

    Bialy, Agata; Jensen, Peter Bjerre; Blanchard, Didier

    2015-01-01

    with spray drying and in situ thermogravimetric and structural characterization, we synthesize a range of new, stable barium-strontium chloride solid solutions with superior ammonia storage densities. By tuning the barium/strontium ratio, different crystallographic phases and compositions can be obtained...

  13. Kinetic Resolution and Stereoselective Synthesis of 3-Substituted Aspartic Acids by Using Engineered Methylaspartate Ammonia Lyases

    NARCIS (Netherlands)

    Raj, Hans; Szymanski, Wiktor; Villiers, Jandré de; Puthan Veetil, Vinod; Quax, Wim J.; Shimamoto, Keiko; Janssen, Dick B.; Feringa, Ben L.; Poelarends, Gerrit J.

    2013-01-01

    Kinetic resolution and asymmetric synthesis of various valuable 3-substituted aspartic acids, which were obtained in fair to good yields with diastereomeric ratio values of up to >98:2 and enantiomeric excess values of up to >99 %, by using engineered methylaspartate ammonia lyases are described.

  14. Determination of ammonia in beers by pervaporation flow injection analysis and spectrophotometric detection.

    Science.gov (United States)

    Wang, Lijuan; Cardwell, Terence J; Cattrall, Robert W; Luque de Castro, Maria D; Kolev, Spas D

    2003-08-29

    A pervaporation flow injection (PFI) method is described for the determination of ammonia in beers. After injecting the sample into a NaOH donor solution, ammonia and other volatiles are transferred in the pervaporation unit from the donor stream to an acceptor stream containing sodium salicylate and nitroprusside, which subsequently mixes with alkaline sodium dichloroisocyanurate to allow the classical Berthelot reaction to take place. The blue-coloured complex formed is monitored spectrophotometrically at 655 nm. A linear calibration curve with a range of 0.1-40 mg l(-1) was obtained. The method has a detection limit of 0.05 mg l(-1) and is capable of a sampling frequency of 11 h(-1) at 4 mg l(-1) ammonia. It was applied successfully to the determination of ammonia in synthetic samples and unfiltered lager beers. The advantages of the present method over the ammonia ion-selective electrode method and the PFI system based on mixed indicator detection are discussed.

  15. CR-100 synthetic zeolite adsorption characteristics toward Northern Banat groundwater ammonia.

    Science.gov (United States)

    Tomić, Željko; Kukučka, Miroslav; Stojanović, Nikoleta Kukučka; Kukučka, Andrej; Jokić, Aleksandar

    2016-10-14

    The adsorption characteristics of synthetic zeolite CR-100 in a fixed-bed system using continuous flow of groundwater containing elevated ammonia concentration were examined. The possibilities for adsorbent mass calculation throughout mass transfer zone using novel mathematical approach as well as zeolite adsorption capacity at every sampling point in time or effluent volume were determined. The investigated adsorption process consisted of three clearly separated steps indicated to sorption kinetics. The first step was characterized by decrease and small changes in effluent ammonia concentration vs. experiment time and quantity of adsorbed ammonia per mass unit of zeolite. The consequences of this phenomenon were showed in the plots of the Freundlich and the Langmuir isotherm models through a better linear correlation according as graphical points contingent to the first step were not accounted. The Temkin and the Dubinin-Radushkevich isotherm models showed the opposite tendency with better fitting for overall measurements. According to the obtained isotherms parameter data, the investigated process was found to be multilayer physicochemical adsorption, and also that synthetic zeolite CR-100 is a promising material for removal of ammonia from Northern Banat groundwater with an ammonia removal efficiency of 90%.

  16. Delignification of miscanthus using ethylenediamine (EDA) with or without ammonia and subsequent enzymatic hydrolysis to sugars.

    Science.gov (United States)

    Padmanabhan, Sasisanker; Schwyter, Philippe; Liu, Zhongguo; Poon, Geoffrey; Bell, Alexis T; Prausnitz, John M

    2016-06-01

    Pretreatment of miscanthus is essential for efficient enzymatic production of cellulosic ethanol. This study reports a possible pretreatment method for miscanthus using aqueous ethylenediamine (EDA) for 30 min at 180 °C with or without ammonia. The mass ratio of miscanthus to EDA was varied from 1:3, 1:1, and 1:0.5, keeping the mass ratio of miscanthus to liquid (EDA + Water) constant at 1:8. The ammonia-to-miscanthus ratio was 1:0.25. After pretreatment with a ratio of 1:3 miscanthus to EDA, about 75 % of the lignin was removed from the raw miscanthus with 90 % retention of cellulose and 50 % of hemicellulose in the recovered solid. Enzymatic hydrolysis of the recovered solid miscanthus gave 63 % glucose and 62 % xylose conversion after 72 h. EDA provides an effective pretreatment for miscanthus, achieving good delignification and enhanced sugar yield by enzyme hydrolysis. Results using aqueous EDA with or without ammonia are much better than those using hot water and compare favorably with those using aqueous ammonia. The delignification efficiency of EDA pretreatment is high compared to that for hot-water pretreatment and is nearly as efficient as that obtained for aqueous-ammonia pretreatment.

  17. [Redistribution of gastrointestinal ammonia into blood in alcohol coma rat: the role in lethal outcome].

    Science.gov (United States)

    Ivnitskiĭ, Iu Iu; Shefer, T V; Reĭniuk, V L

    2010-01-01

    At 3 h after the intragastral administration of ethanol (446 mmol/kg) the blood ammonia concentration in v. portae increased 1.4 times, in v. cava inf. caudally of vv. renales inflow - 2.2 times, cranially of vv. hepaticae - 2.5 times, and in blood obtained by decapitation - by 65%7. The rate of ammonia accumulation in 'avage medium injected intraperitoneally was triple as that in intact rats. The exposure to atmospheric ammoniac (0.84-1.07 mg/l) for 3 h resuited in increasing blood ammonia concentration 2.4 times compared with the isolated ethanol action. The ammonia inhalation promoted the lethal action of ethanol with a dose alteration factor of 0.81 and suppressed gas-exchange. The promotion of the ethanol lethal action by the non-lethal ammonium acetate dosage has been observed. These data suggest that in rat, the coma-inducing ethanol ingestion promotes the translocation of intestinal ammonia into the common bloodstream, which has a detrimental effect on the outcome of alcohol coma.

  18. Flame Spray Synthesis and Ammonia Sensing Properties of Pure α-MoO3 Nanosheets

    Directory of Open Access Journals (Sweden)

    Gagan Jodhani

    2016-01-01

    Full Text Available This paper highlights the flame spray synthesis of α-MoO3 using ammonium molybdate as precursor. The as-synthesized particles obtained were found to be ammonium molybdenum oxide and belonged to the triclinic crystal system. The particles crystallized to α-MoO3 upon thermal treatment at 500°C. Sensors were prepared by drop coating the powders onto alumina substrates coated with platinum electrodes and sensing tests were conducted evaluating the detection of ammonia concentrations down to ppb level concentration in air. The flame synthesized α-MoO3 based sensors show high sensitivity towards ammonia and may potentially be used in breath ammonia gas diagnostics.

  19. Measurements of the horizontal gradient of ammonia over a conifer forest in Denmark

    DEFF Research Database (Denmark)

    Hovmand, M.F.; Andersen, H.V.; Løfstrøm, P.

    1998-01-01

    Horizontal gradients of ammonia have been measured in order to determine the spatial variation of the concentration above a forest as a function of distance from ammonia emitting areas. Measurements were carried out in June 1994 during conditions with winds from north and west. Concentration leve...... concentration gradients, although calculated concentration levels may be higher than measured due to the use of yearly average emissions as input to the model calculations. (C) 1998 Elsevier Science Ltd. All rights reserved....... in the forest; in general the percentage decreases were lower during northerly winds (16%) than those obtained during westerly winds (67%). This is probably due to the larger extension of emitting areas towards north than towards the west. Model calculations are comparable with the measured ammonia...

  20. Non-intrusive, fast and sensitive ammonia detection by laser photothermal deflection

    International Nuclear Information System (INIS)

    Vries, H.S.M. de; Harren, F.J.M.; Wyers, G.P.; Otjes, R.P.; Slanina, J.; Reuss, J.

    1995-01-01

    A recently developed non-intrusive photothermal deflection (PTD) instrument allows sensitive, rapid and quantitative detection of local ammonia concentrations in the air. Ammonia is vibrationally excited by an infrared CO 2 laser in an intracavity configuration. A HeNe beam passing over the CO 2 laser beam (multipass arrangement) is deflected by the induced refractive index gradient. The detection limit for ammonia in ambient air is 0.5 ppbv with a spatial resolution of a few mm 3 . The time resolution is 0.1 s (single line) or 15 s (multi line). The system is fully automated and suited for non-stop measuring periods of at least one week. Results were compared to those obtained with a continuous-flow denuder (CFD). (author)

  1. Experimental particle formation rates spanning tropospheric sulfuric acid and ammonia abundances, ion production rates, and temperatures

    CERN Document Server

    Kürten, Andreas; Almeida, Joao; Kupiainen-Määttä, Oona; Dunne, Eimear M.; Duplissy, Jonathan; Williamson, Christina; Barmet, Peter; Breitenlechner, Martin; Dommen, Josef; Donahue, Neil M.; Flagan, Richard C.; Franchin, Alessandro; Gordon, Hamish; Hakala, Jani; Hansel, Armin; Heinritzi, Martin; Ickes, Luisa; Jokinen, Tuija; Kangasluoma, Juha; Kim, Jaeseok; Kirkby, Jasper; Kupc, Agnieszka; Lehtipalo, Katrianne; Leiminger, Markus; Makhmutov, Vladimir; Onnela, Antti; Ortega, Ismael K.; Petäjä, Tuukka; Praplan, Arnaud P.; Riccobono, Francesco; Rissanen, Matti P.; Rondo, Linda; Schnitzhofer, Ralf; Schobesberger, Siegfried; Smith, James N.; Steiner, Gerhard; Stozhkov, Yuri; Tomé, António; Tröstl, Jasmin; Tsagkogeorgas, Georgios; Wagner, Paul E.; Wimmer, Daniela; Ye, Penglin; Baltensperger, Urs; Carslaw, Ken; Kulmala, Markku; Curtius, Joachim

    2016-01-01

    Binary nucleation of sulfuric acid and water as well as ternary nucleation involving ammonia arethought to be the dominant processes responsible for new particle formation (NPF) in the cold temperaturesof the middle and upper troposphere. Ions are also thought to be important for particle nucleation inthese regions. However, global models presently lack experimentally measured NPF rates under controlledlaboratory conditions and so at present must rely on theoretical or empirical parameterizations. Here withdata obtained in the European Organization for Nuclear Research CLOUD (Cosmics Leaving OUtdoor Droplets)chamber, we present the first experimental survey of NPF rates spanning free tropospheric conditions. Theconditions during nucleation cover a temperature range from 208 to 298 K, sulfuric acid concentrationsbet ween 5 × 105and 1 × 109cm3, and ammonia mixing ratios from zero added ammonia, i.e., nominally purebinary, to a maximum of ~1400 parts per trillion by volume (pptv). We performed nucleation s...

  2. Apparent deposition velocity and compensation point of ammonia inferred from gradient measurements above and through alfalfa

    Science.gov (United States)

    Dabney, Seth M.; Bouldin, David R.

    Understanding the cycling of ammonia between croplands and the atmosphere is of importance to agriculturalists and atmospheric scientists. Flux densities of gaseous ammonia (NH 3), particulate ammonium (NH 4+), and total ammoniacal nitrogen (AN) were measured using an aerodynamic method above an alfalfa ( Medicago sativa, L.) canopy between April and July 1981 at a rural location in central New York State. In air not influenced by local sources, NH 3 and NH 4+ averaged 1.5 and 3.0 ppb, respectively, at 1 m above the crop. Ambient NH 4+ varied consistently with synoptic air masses, being lowest (2.3 ppb) for NW and highest (6.4 ppb) for SW flows. Concentrations and gradients of both species were higher during periods of hay harvest. Gradients of NH 3 were much steeper than those of NH 4+ within the alfalfa canopy, but NH 4+ contributed appreciably (36% on average) to above-canopy AN gradients. Alfalfa's NH 3 compensation point was estimated by combining concentration and gradient data with transport resistances. Gaseous gradients indicated a compensation point of 2 ppb, lower than previously published estimates. Conversion of NH 3 to NH 4+ within the canopy air could have reduced NH 3 gradients and caused a low estimate of the compensation point. Acidic aerosols, by keeping NH 3 levels low, may compete with plants for NH 3. Future studies of ammonia exchange should distinguish between NH 3 and NH 4+ if flux densities are to be related to ambient conditions. Total AN level is a poor predictor of soil-plant-atmosphere ammonia exchange since high AN was frequently associated with low NH 3, and NH 3 is more surface reactive than NH 4+.

  3. An Intelligent Ammonia Sensor for Livestock Breeding Monitoring

    OpenAIRE

    Wang, Yang; Fu, Zetian; Zhang, Lingxian; Li, Xinxing; Xu, Dan; Zeng, Lihua; Ma, Juncheng; Peng, Fa

    2013-01-01

    International audience; Ammonia concentration is the major parameter to evaluate livestock breeding farms atmosphere quality and it also is regarded as the key indicator to describe the production of livestock breeding farms. Based on the oxidation characteristics of ammonia, this paper presented a new intelligent detecting instrument, the intelligent ammonia sensor, for the measurement of ammonia concentration, which used the microcontroller STM8L152 as the key control module. However, the T...

  4. Ammonia production, excretion, toxicity, and defense in fish: A Review

    Directory of Open Access Journals (Sweden)

    Alex Y K Ip

    2010-10-01

    Full Text Available Many fishes are ammonotelic but some species can detoxify ammonia to glutamine or urea. Certain fish species can accumulate high levels of ammonia in the brain or defense against ammonia toxicity by enhancing the effectiveness of ammonia excretion through active NH4+ transport, manipulation of ambient pH, or reduction in ammonia permeability through the branchial and cutaneous epithelia. Recent reports on ammonia toxicity in mammalian brain reveal the importance of permeation of ammonia through the blood-brain barrier and passages of ammonia and water through transporters in the plasmalemma of brain cells. Additionally, brain ammonia toxicity could be related to the passage of glutamine through the mitochondrial membranes into the mitochondrial matrix. On the other hand, recent reports on ammonia excretion in fish confirm the involvement of Rhesus glycoproteins in the branchial and cutaneous epithelia. Therefore, this review focuses on both the earlier literature and the up-to-date information on the problems and mechanisms concerning the permeation of ammonia, as NH3, NH4+ or proton-neutral nitrogenous compounds, across mitochondrial membranes, the blood-brain barrier, the plasmalemma of neurons, and the branchial and cutaneous epithelia of fish. It also addresses how certain fishes with high ammonia tolerance defend against ammonia toxicity through the regulation of the permeation of ammonia and related nitrogenous compounds through various types of membranes. It is hoped that this review would revive the interests in investigations on the passage of ammonia through the mitochondrial membranes and the blood-brain barrier of ammonotelic fishes and fishes with high brain ammonia-tolerance, respectively.

  5. Optimal flux patterns in cellular metabolic networks

    Energy Technology Data Exchange (ETDEWEB)

    Almaas, E

    2007-01-20

    The availability of whole-cell level metabolic networks of high quality has made it possible to develop a predictive understanding of bacterial metabolism. Using the optimization framework of flux balance analysis, I investigate metabolic response and activity patterns to variations in the availability of nutrient and chemical factors such as oxygen and ammonia by simulating 30,000 random cellular environments. The distribution of reaction fluxes is heavy-tailed for the bacteria H. pylori and E. coli, and the eukaryote S. cerevisiae. While the majority of flux balance investigations have relied on implementations of the simplex method, it is necessary to use interior-point optimization algorithms to adequately characterize the full range of activity patterns on metabolic networks. The interior-point activity pattern is bimodal for E. coli and S. cerevisiae, suggesting that most metabolic reaction are either in frequent use or are rarely active. The trimodal activity pattern of H. pylori indicates that a group of its metabolic reactions (20%) are active in approximately half of the simulated environments. Constructing the high-flux backbone of the network for every environment, there is a clear trend that the more frequently a reaction is active, the more likely it is a part of the backbone. Finally, I briefly discuss the predicted activity patterns of the central-carbon metabolic pathways for the sample of random environments.

  6. 46 CFR 151.50-32 - Ammonia, anhydrous.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Ammonia, anhydrous. 151.50-32 Section 151.50-32 Shipping... BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-32 Ammonia, anhydrous. (a) The anhydrous ammonia tanks may be installed in the bulk liquid cargo tanks provided the liquid surrounding the...

  7. Nitrite as a stimulus for ammonia-starved Nitrosomonas europaea

    NARCIS (Netherlands)

    Laanbroek, H.J.; Bär-Gilissen, M.J.; Hoogveld, H.L.

    2002-01-01

    Ammonia-starved cells of Nitrosomonas europaea are able to preserve a high level of ammonia-oxidizing activity in the absence of ammonium. However, when the nitrite-oxidizing cells that form part of the natural nitrifying community do not keep pace with the ammonia-oxidizing cells, nitrite

  8. The dominant acetate degradation pathway/methanogenic composition in full-scale anaerobic digesters operating under different ammonia levels

    DEFF Research Database (Denmark)

    Fotidis, Ioannis; Karakashev, Dimitar Borisov; Angelidaki, Irini

    2014-01-01

    Ammonia is a major environmental factor influencing biomethanation in full-scale anaerobic digesters. In this study, the effect of different ammonia levels on methanogenic pathways and methanogenic community composition of full-scale biogas plants was investigated. Eight full-scale digesters...... operating under different ammonia levels were sampled, and the residual biogas production was followed in fed-batch reactors. Acetate, labelled in the methyl group, was used to determine the methanogenic pathway by following the 14CH4 and 14CO2 production. Fluorescence in situ hybridisation was used...... to determine the methanogenic communities’ composition. Results obtained clearly demonstrated that syntrophic acetate oxidation coupled with hydrogenotrophic methanogenesis was the dominant pathway in all digesters with high ammonia levels (2.8–4.57 g NH4 +-N L−1), while acetoclastic methanogenic pathway...

  9. Secondary emission from a CuBe target due to bombardment with parent and fragment ions of ammonia and phosphine

    International Nuclear Information System (INIS)

    Maerk, T.D.

    1977-01-01

    The secondary electron emission of the first dynode of a CuBe alloy sixteen dynode electron multiplier has been studied in the course of electron impact ionization studies of ammonia and phosphine. Relative secondary electron emission coefficients have been obtained for the singly and doubly charged parent and fragment ions of ammonia, ammonia-d 3 , phosphine and phosphine-d 3 for kinetic energies of 5,25 and 10,5 keV. It has been found, that in general deuterated ions have smaller γ coefficients, that ammonia ions have larger γ coefficients than corresponding phosphine ions, and that the γ coefficients increase with the complexity of the ion under study. (Auth.)

  10. Community Structure of Ammonia-Oxidizing Archaea and Ammonia-Oxidizing Bacteria in Soil Treated with the Insecticide Imidacloprid

    Directory of Open Access Journals (Sweden)

    Mariusz Cycoń

    2015-01-01

    Full Text Available The purpose of this experiment was to assess the effect of imidacloprid on the community structure of ammonia-oxidizing archaea (AOA and ammonia-oxidizing bacteria (AOB in soil using the denaturing gradient gel electrophoresis (DGGE approach. Analysis showed that AOA and AOB community members were affected by the insecticide treatment. However, the calculation of the richness (S and the Shannon-Wiener index (H values for soil treated with the field rate (FR dosage of imidacloprid (1 mg/kg soil showed no changes in measured indices for the AOA and AOB community members. In turn, the 10*FR dosage of insecticide (10 mg/kg soil negatively affected the AOA community, which was confirmed by the decrease of the S and H values in comparison with the values obtained for the control soil. In the case of AOB community, an initial decline followed by the increase of the S and H values was obtained. Imidacloprid decreased the nitrification rate while the ammonification process was stimulated by the addition of imidacloprid. Changes in the community structure of AOA and AOB could be due to an increase in the concentration of N-NH4+, known as the most important factor which determines the contribution of these microorganisms to soil nitrification.

  11. Ammonia emission time profiles based on manure transport data improve ammonia modelling across north western Europe

    NARCIS (Netherlands)

    Hendriks, C.; Kranenburg, R.; Kuenen, J.J.P.; Bril, B. van den; Verguts, V.; Schaap, M.

    2016-01-01

    Accurate modelling of mitigation measures for nitrogen deposition and secondary inorganic aerosol (SIA) episodes requires a detailed representation of emission patterns from agriculture. In this study the meteorological influence on the temporal variability of ammonia emissions from livestock

  12. Chemical Safety Alert: Hazards of Ammonia Releases at Ammonia Refrigeration Facilities

    Science.gov (United States)

    Anhydrous ammonia is used as a refrigerant in mechanical compression systems, often liquefied under pressure which increases exposure risk due to potential for rapid release into the air as a toxic gas.

  13. Planar optical waveguide sensor of ammonia

    Science.gov (United States)

    Sarkisov, Sergey S.; Curley, Michael J.; Boykin, Courtney; Diggs, Darnell E.; Grote, James G.; Hopkins, Frank K.

    2004-12-01

    We describe a novel sensor of ammonia based on a planar optical waveguide made of a thin film of polymer polyimide doped with indicator dye bromocresol purple. The film of dye-doped polyimide demonstrated reversible increase of absorption with a peak near 600 nm in response to presence of ammonia in ambient air. Coupling of input and output optic fibers with the waveguide was done by means of coupling prisms or coupling grooves. The latter configuration has the advantage of low cost, less sensitivity to temperature variation, and the possibility of coupling from both sides of the waveguide. Special experimental setup was built to test the sensor. It included test gas chamber with sealed optic fiber feed-throughs, gas filling line, laser source, photodetector, and signal processing hardware and software. The sensor was capable of detecting 100 ppm of ammonia in air within 8 seconds. Further increase of sensitivity can be achieved by adding more dye dopant to the polymer, increase of the length of the waveguide, and suppression of noise. Overexposure of the sensor to more than 5000 ppm of ammonia led to the saturation of the polymer film and, as a result, significant decrease of sensitivity and increase of the response time. The sensor can be used as low cost component of a distributed optical network of chemical sensors for monitoring presence of hazardous industrial pollutants in air.

  14. Effect of ammonia on Swiss albino mice

    Science.gov (United States)

    Hilado, C. J.; Casey, C. J.; Furst, A.

    1977-01-01

    Times to incapacitation and death and LC /50/ values were determined for Swiss albino male mice exposed to different concentrations of ammonia in a 4.2 liter hemispherical chamber. The LC/50/ for a 30 minute exposure was 21,430 ppm.

  15. The synthesis of ammonia from its elements

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 9. The Synthesis of Ammonia from its Elements. Fritz Haber. Classics Volume 7 Issue 9 September 2002 pp 86-94. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/007/09/0086-0094 ...

  16. USDA-EPA Collaborative Ammonia Research

    Science.gov (United States)

    In 2014, a work group was formed between USDA and EPA to facilitate information exchange on ammonia emissions from agriculture, air quality impacts and emission mitigation options and to identify opportunities for collaboration. This document provides background on the work grou...

  17. Adsorption of Ammonia on Regenerable Carbon Sorbents

    Science.gov (United States)

    Wójtowicz, Marek A.; Cosgrove, Jesph E.; Serio, Michael A..; Wilburn, Monique

    2015-01-01

    Results are presented on the development of reversible sorbents for the combined carbon dioxide, moisture, and trace-contaminant (TC) removal for use in Extravehicular Activities (EVAs), and more specifically in the Primary Life Support System (PLSS). The currently available life support systems use separate units for carbon dioxide, trace contaminants, and moisture control, and the long-term objective is to replace the above three modules with a single one. Data on sorption and desorption of ammonia, which is a major TC of concern, are presented in this paper. The current TC-control technology involves the use of a packed bed of acid-impregnated granular charcoal, which is non-regenerable, and the carbon-based sorbent under development in this project can be regenerated by exposure to vacuum at room temperature. In this study, several carbon sorbents were fabricated and tested for ammonia sorption. Ammonia-sorption capacity was related to carbon pore structure characteristics, and the temperature of oxidative carbon-surface treatment was optimized for enhanced ammonia-sorption performance.

  18. Footprints on Ammonia Concentrations from Environmental Regulations

    DEFF Research Database (Denmark)

    Skjøth, Carsten Ambelas; Ellermann, Thomas; Hertel, Ole

    2008-01-01

    Releases of ammonia (NH3) to the atmosphere contribute significantly to the desposition of nitrogen to both terrestrial and aquatic ecosystems. This is the background for the national NH3 emission ceilings in Europe. However, in some countries the national legislation aims not only to meet theese...

  19. Reducing ammonia volatilization from compound fertilizers ...

    African Journals Online (AJOL)

    Paul

    2012-09-13

    Sep 13, 2012 ... formulated fertilizer + 18.92 g zeolite (T5), 22.30 g 10:10:10 formulated fertilizer + 4.06 g zeolite (T6), and ... compound fertilizer could minimize ammonia loss. ..... North China Plan. Nutr. Cycl. Agroecosyst.63:187-195. Cottenie A (1980). Soil testing and plant testing as a basis of fertilizer recommendation.

  20. 1 Ammonia Concentrations in Different Aquaculture 2

    African Journals Online (AJOL)

    Administrator

    density, low water exchange rates, water source and the alkaline medium of the systems. Low unionized ammonia in earthen pond and natural pond was attributed to the presence of phytoplankton, high water exchanges, feeding system, low acidity and relatively low temperature. Remediating measures such as the use of ...

  1. Ammonia synthesis from first principles calculations

    DEFF Research Database (Denmark)

    Honkala, Johanna Karoliina; Hellman, Anders; Remediakis, Ioannis

    2005-01-01

    The rate of ammonia synthesis over a nanoparticle ruthenium catalyst can be calculated directly on the basis of a quantum chemical treatment of the problem using density functional theory. We compared the results to measured rates over a ruthenium catalyst supported on magnesium aluminum spinet...

  2. Physiological plasticity of the thermophilic ammonia oxidizing archaeon Nitrosocaldus yellowstonii in response to a changing environment

    Science.gov (United States)

    Jewell, T.; Johnson, A.; Gelsinger, D.; de la Torre, J. R.

    2012-12-01

    consumed NH3 from NH4Cl when both substrates were provided in equal molar concentrations. However, the urease alpha subunit ureC was expressed in both the presence and absence of urea. One consequence of urea hydrolysis is consumption of intracellular protons during the reaction. As ammonia oxidation produces H+, leading to a decrease in pH, the hydrolysis of urea prior to ammonia oxidation may help alleviate metabolism-driven pH change in HL72. A survey of archaeal ureC sequences from metagenomic data covering a range of hydrothermal features revealed that ureolytic potential is common to many Nitrosocaldus-like organisms and is geographically widespread. Measurements of urea from siliceous circumneutral springs indicate that the concentrations are generally low, below 10 μM. One possible explanation for low steady state urea concentrations is high consumption rates by ureolytic organisms. This, combined with abiotic thermal degradation, may mask high fluxes of urea in microbial hot spring communities.

  3. Orion Ammonia Boiler System Preflight Test Preparations

    Science.gov (United States)

    Levitt, Julia L.

    2017-01-01

    The Environmental Controls and Life Support Systems (ECLSS) branch at Kennedy Space Center (KSC) is currently undergoing preparations for ground testing of the Orion Multi-Purpose Crew Vehicle (MPCV) to prepare its subsystems for EM-1 (Exploration Mission-1). EM-1, Orions second unmanned flight, is a three-week long lunar mission during which the vehicle will complete a 6-day retrograde lunar orbit before returning to Earth. This paper focuses on the work done during the authors 16-week internship with the Mechanical Engineering Branch of KSCs Engineering Directorate. The authors project involved assisting with the preparations for testing the Orion MPCVs ammonia boiler system. The purpose of the ammonia boiler system is to keep the spacecraft sufficiently cool during the reentry portion of its mission, from service module (SM) separation to post-landing. This system is critical for keeping both the spacecraft (avionics and electronics) and crew alive during reentry, thus a successful test of the system is essential to the success of EM-1. XXXX The author was able to draft a detailed outline of the procedure for the ammonia system functional test. More work will need to be done on the vehicle power-up and power-down portions of the procedure, but the ammonia system testing portion of the procedure is thorough and includes vehicle test configurations, vehicle commands, and GSE. The author was able to compile a substantial list of questions regarding the ammonia system functional test with the help of her mentors. A significant number of these questions were answered in the teleconferences with Lockheed Martin.

  4. Ammonia and ammonium hydroxide sensors for ammonia/water absorption machines: Literature review and data compilation

    Science.gov (United States)

    Anheier, N. C., Jr.; McDonald, C. E.; Cuta, J. M.; Cuta, F. M.; Olsen, K. B.

    1995-05-01

    This report describes an evaluation of various sensing techniques for determining the ammonia concentration in the working fluid of ammonia/water absorption cycle systems. The purpose was to determine if any existing sensor technology or instrumentation could provide an accurate, reliable, and cost-effective continuous measure of ammonia concentration in water. The resulting information will be used for design optimization and cycle control in an ammonia-absorption heat pump. Pacific Northwest Laboratory (PNL) researchers evaluated each sensing technology against a set of general requirements characterizing the potential operating conditions within the absorption cycle. The criteria included the physical constraints for in situ operation, sensor characteristics, and sensor application. PNL performed an extensive literature search, which uncovered several promising sensing technologies that might be applicable to this problem. Sixty-two references were investigated, and 33 commercial vendors were identified as having ammonia sensors. The technologies for ammonia sensing are acoustic wave, refractive index, electrode, thermal, ion-selective field-effect transistor (ISFET), electrical conductivity, pH/colormetric, and optical absorption. Based on information acquired in the literature search, PNL recommends that follow-on activities focus on ISFET devices and a fiber optic evanescent sensor with a colormetric indicator. The ISFET and fiber optic evanescent sensor are inherently microminiature and capable of in situ measurements. Further, both techniques have been demonstrated selective to the ammonium ion (NH4(+)). The primary issue remaining is how to make the sensors sufficiently corrosion-resistant to be useful in practice.

  5. Rectal administration of 13N-ammonia in the study of ammonia metabolism

    International Nuclear Information System (INIS)

    Koen, Hirofumi

    1980-01-01

    13 N-ammonia produced by the cyclotron was instilled intrarectally in patients with liver diseases for the study of the turnover of rectally absorbed 13 N-ammonia. A positron camera connected to an on-line computer system was used for imaging of the liver and heart; 13 N-activity over the head was also recorded. Sequential changes of 13 N-activity in blood was measured, and chromatographic analysis of 13 N-labeled substances in blood was carried out using a Dowex 50W x 8 column. In the control, 13 N-ammonia was absorbed quickly into blood visualizing the liver shortly after administration, and hepatic uptake of 13 N-ammonia reached a plateau in 10 -- 15 min, whereas in patients with cirrhosis, the lung and heart were visualized in 5 min when the liver image was still faint. 13 N-activity over the head was apparently higher in the cirrhotic group. It was suggested that a large proportion of absorbed 13 N-ammonia bypassed liver cells and reached peripheral tissues. The heart/liver ratio of 13 N and 13 N over the head were closely correlated with various indices of portal hypertension. The relative proportion of 13 N-metabolites in blood was lower at 5 min and 15 min after administration in cirrhosis, suggesting a reduced capacity of the liver to remove and metabolize ammonia. (author)

  6. Ammonia and ammonium hydroxide sensors for ammonia/water absorption machines: Literature review and data compilation

    Energy Technology Data Exchange (ETDEWEB)

    Anheier, N.C. Jr.; McDonald, C.E.; Cuta, J.M.; Cuta, F.M.; Olsen, K.B.

    1995-05-01

    This report describes an evaluation of various sensing techniques for determining the ammonia concentration in the working fluid of ammonia/water absorption cycle systems. The purpose of this work was to determine if any existing sensor technology or instrumentation could provide an accurate, reliable, and cost-effective continuous measure of ammonia concentration in water. The resulting information will be used for design optimization and cycle control in an ammonia-absorption heat pump. PNL researchers evaluated each sensing technology against a set of general requirements characterizing the potential operating conditions within the absorption cycle. The criteria included the physical constraints for in situ operation, sensor characteristics, and sensor application. PNL performed an extensive literature search, which uncovered several promising sensing technologies that might be applicable to this problem. Sixty-two references were investigated, and 33 commercial vendors were identified as having ammonia sensors. The technologies for ammonia sensing are acoustic wave, refractive index, electrode, thermal, ion-selective field-effect transistor (ISFET), electrical conductivity, pH/colormetric, and optical absorption. Based on information acquired in the literature search, PNL recommends that follow-on activities focus on ISFET devices and a fiber optic evanescent sensor with a colormetric indicator. The ISFET and fiber optic evanescent sensor are inherently microminiature and capable of in situ measurements. Further, both techniques have been demonstrated selective to the ammonium ion (NH{sub 4}{sup +}). The primary issue remaining is how to make the sensors sufficiently corrosion-resistant to be useful in practice.

  7. Prediction of ammonia emission from dairy cattle manure based on milk urea nitrogen: relation of milk urea nitrogen to ammonia emissions.

    Science.gov (United States)

    Burgos, S A; Embertson, N M; Zhao, Y; Mitloehner, F M; DePeters, E J; Fadel, J G

    2010-06-01

    The main objectives of this study were to assess the relationship between ammonia emissions from dairy cattle manure and milk urea N (MUN; mg/dL) and to test whether the relationship was affected by stage of lactation and the dietary crude protein (CP) concentration. Twelve lactating multiparous Holstein cows were randomly selected and blocked into 3 groups of 4 cows intended to represent early [123+/-26 d in milk (DIM)], mid (175+/-3 DIM), and late (221+/-12 DIM) lactation stages. Cows within each stage of lactation were randomly assigned to a treatment sequence within a split-plot Latin square design balanced for carryover effects. Stage of lactation formed the main plots (squares) and dietary CP levels (15, 17, 19, and 21% of diet dry matter) formed the subplots. The experimental periods lasted 7 d, with d 1 to 6 used for adjustment to diets and d 7 used for total collection of feces and urine as well as milk sample collection. The feces and urine from each cow were mixed in the proportions in which they were excreted to make slurry that was used to measure ammonia emissions at 22.5 degrees C over 24 h using flux chambers. Samples of manure slurry were taken before and after ammonia emission measurements. The amount of slurry increased by 22% as dietary CP concentration increased from 15 to 21%, largely because of a greater urine volume (25.3 to 37.1 kg/d). Initial urea N concentration increased linearly with dietary CP from 153.5 to 465.2 mg/dL in manure slurries from cows fed 15 to 21% CP diets. Despite the large initial differences, the final concentration of urea N in manure slurries was less than 10.86 mg/dL for all dietary treatments. The final total ammoniacal N concentration in manure slurries increased linearly from 228.2 to 508.7 mg/dL as dietary CP content increased from 15 to 21%. Ammonia emissions from manure slurries ranged between 57 and 149 g of N/d per cow and increased linearly with dietary CP content, but were unaffected by stage of lactation

  8. Obtaining of inulin acetate

    OpenAIRE

    Khusenov, Arslonnazar; Rakhmanberdiev, Gappar; Rakhimov, Dilshod; Khalikov, Muzaffar

    2014-01-01

    In the article first obtained inulin ester inulin acetate, by etherification of inulin with acetic anhydride has been exposed. Obtained product has been studied using elementary analysis and IR spectroscopy.

  9. Ammonia emission inventory for the state of Wyoming

    Energy Technology Data Exchange (ETDEWEB)

    Kirchstetter, Thomas W.; Maser, Colette R.; Brown, Nancy J.

    2003-12-17

    Ammonia (NH{sub 3}) is the only significant gaseous base in the atmosphere and it has a variety of impacts as an atmospheric pollutant, including the formation of secondary aerosol particles: ammonium sulfate and ammonium nitrate. NH{sub 3} preferentially forms ammonium sulfate; consequently ammonium nitrate aerosol formation may be limited by the availability of NH{sub 3}. Understanding the impact of emissions of oxides of sulfur and nitrogen on visibility, therefore, requires accurately determined ammonia emission inventories for use in air quality models, upon which regulatory and policy decisions increasingly depend. This report presents an emission inventory of NH{sub 3} for the state of Wyoming. The inventory is temporally and spatially resolved at the monthly and county level, and is comprised of emissions from individual sources in ten categories: livestock, fertilizer, domestic animals, wild animals, wildfires, soil, industry, mobile sources, humans, and publicly owned treatment works. The Wyoming NH{sub 3} inventory was developed using the Carnegie Mellon University (CMU) Ammonia Model as framework. Current Wyoming-specific activity data and emissions factors obtained from state agencies and published literature were assessed and used as inputs to the CMU Ammonia Model. Biogenic emissions from soils comprise about three-quarters of the Wyoming NH{sub 3} inventory, though emission factors from soils are highly uncertain. Published emission factors are scarce and based on limited measurements. In Wyoming, agricultural land, rangeland, and forests comprise 96% of the land area and essentially all of the estimated emissions from soils. Future research on emission rates of NH{sub 3} for these land categories may lead to a substantial change in the magnitude of soil emissions, a different inventory composition, and reduced uncertainty in the inventory. While many NH{sub 3} inventories include annual emissions, air quality modeling studies require finer temporal

  10. Cerebral ammonia uptake and accumulation during prolonged exercise in humans

    DEFF Research Database (Denmark)

    Nybo, Lars; Dalsgaard, Mads K.; Steensberg, Adam

    2005-01-01

    We evaluated whether peripheral ammonia production during prolonged exercise enhances the uptake and subsequent accumulation of ammonia within the brain. Two studies determined the cerebral uptake of ammonia (arterial and jugular venous blood sampling combined with Kety-Schmidt-determined cerebral...... blood flow; n = 5) and the ammonia concentration in the cerebrospinal fluid (CSF; n = 8) at rest and immediately following prolonged exercise either with or without glucose supplementation. There was a net balance of ammonia across the brain at rest and at 30 min of exercise, whereas 3 h of exercise...... exercise with glucose, and further to 16.1 ± 3.3 µM after the placebo trial (P

  11. Seasonal variation in communities of ammonia-oxidizing bacteria based on polymerase chain reaction - denaturing gradient gel electrophoresis in a biofilm reactor for drinking water pretreatment.

    Science.gov (United States)

    Zhang, Xiao-Wen; Qin, Ying-Ying; Ren, Hong-Qiang; Li, Dao-Tang; Yang, Hong

    2008-05-01

    The diversity and variation of total and active ammonia-oxidizing bacteria in a full-scale aerated submerged biofilm reactor for drinking water pretreatment were characterized by clone libraries and denaturing gradient gel electrophoresis (DGGE) analysis of 16S rRNA and its gene during a whole year. Sequences obtained from clone libraries affiliated with the Nitrosomonas oligotropha lineage and the Nitrosomonas communis lineage. An uncultured subgroup of Nitrosomonas communis lineage was also detected. Seasonal variations in both total and active ammonia-oxidizing bacteria communities were observed in the DGGE profiles, but an RNA-based analysis reflected more obvious dynamic changes in ammonia-oxidizer community than a DNA-based approach. Statistical study based on canonical correspondence analysis showed that a community shift of active ammonia oxidizers was significantly influenced by temperature and pH, but no significant correlation was found between environmental variables and total ammonia-oxidizer community shift.

  12. Ammonia and Carbon Dioxide Concentrations in a Layer House

    Directory of Open Access Journals (Sweden)

    Ilker Kilic

    2014-08-01

    Full Text Available Higher concentrations of ammonia (NH3 and carbon dioxide (CO2 in animal barns can negatively affect production and health of animals and workers. This paper focuses on measurements of summer concentrations of ammonia (NH3 and carbon dioxide (CO2 in a naturally ventilated laying henhouse located at an egg production facility in Bursa region, western Turkey. Also, indoor and ambient environmental conditions such as temperature and relative humidity were measured simultaneously with pollutant gas concentrations. The average NH3 concentrations during summer of 2013 was 8.05 ppm for exhaust and 5.42 ppm for inlet while average CO2 concentration was 732 ppm for exhaust and 625 ppm for inlet throughout summer. The overall minimum, average and maximum values and humidity were obtained as 16.8°C, 24.72°C, and 34.71°C for indoor temperature and 33.64%, 63.71%, and 86.18% for relative humidity. The lowest exhaust concentrations for NH3 and CO2 were 6.98 ppm and 609 ppm, respectively. They were measured in early morning at the maximum diurnal ventilation rate in July 2013 and August 2013. The highest concentrations were 10.58 ppm for NH3 and 904 ppm for CO2 recorded in the afternoon when the ventilation rate was the lowest in June 2013.

  13. Time delay for aerial ammonia concentration measurements in livestock buildings.

    Science.gov (United States)

    Rom, Hans Benny; Zhang, Guo-Qiang

    2010-01-01

    Correct measurements of ammonia concentration in air still present considerable challenges. The high water solubility and polarity can cause it to adsorb on surfaces in the entire sampling system, including sampling lines, filters, valves, pumps and instruments, causing substantial measuring errors and time delays. To estimate time delay characteristics of a Photo Acoustic Multi Gas Monitor 1312 and a Multi Point Sampler continuous measurement of aerial ammonia concentrations at different levels was performed. In order to obtain reproducible data, a wind tunnel was used to generate selected concentrations inside and a background concentration representing the air inlet of the tunnel. Four different concentration levels (0.8 ppm, 6.2 ppm, 9.7 ppm and 13.7 ppm) were used in the experiments, with an additional outdoor concentration level as background. The results indicated a substantial time delay when switching between the measuring positions with high and low concentration and vice versa. These properties may course serious errors for estimation of e.g. gas emissions whenever more than one measuring channel is applied. To reduce the measurement errors, some suggestions regarding design of the measurement setup and measuring strategies were presented.

  14. Time Delay for Aerial Ammonia Concentration Measurements in Livestock Buildings

    Directory of Open Access Journals (Sweden)

    Hans Benny Rom

    2010-05-01

    Full Text Available Correct measurements of ammonia concentration in air still present considerable challenges. The high water solubility and polarity can cause it to adsorb on surfaces in the entire sampling system, including sampling lines, filters, valves, pumps and instruments, causing substantial measuring errors and time delays. To estimate time delay characteristics of a Photo Acoustic Multi Gas Monitor 1312 and a Multi Point Sampler continuous measurement of aerial ammonia concentrations at different levels was performed. In order to obtain reproducible data, a wind tunnel was used to generate selected concentrations inside and a background concentration representing the air inlet of the tunnel. Four different concentration levels (0.8 ppm, 6.2 ppm, 9.7 ppm and 13.7 ppm were used in the experiments, with an additional outdoor concentration level as background. The results indicated a substantial time delay when switching between the measuring positions with high and low concentration and vice versa. These properties may course serious errors for estimation of e.g. gas emissions whenever more than one measuring channel is applied. To reduce the measurement errors, some suggestions regarding design of the measurement setup and measuring strategies were presented.

  15. Ammonia sensor and antibacterial activities of green zinc oxide nanoparticles

    Directory of Open Access Journals (Sweden)

    S. Khaleel Basha

    2016-09-01

    Full Text Available Zinc oxide nanoparticles was synthesized by alginate (A through a rapid and a facile step in the aqueous solution condition at room temperature. Fabrication of zinc oxide nanoparticles was characterized by ATR-FTIR, TEM and XRD. ATR-FTIR analysis confirmed that the A/ZnO NPs were encapsulated by the polymerized alginate. Their shape, structure and composition were assessed by SEM. TEM and XRD analysis indicated that the A/ZnO NPs give evidence of the crystalline nature of ZnO and hybrid NPs structure, which is suitable for ammonia gas sensor development. The controlled size of the A/ZnO NPs obtained using this innovative synthesis strategy minimizes the response time of 2–3 s to sense the ammonia gas significantly with a detection limit of 1 ppm were found at room temperature. The antibacterial tests revealed that the A/ZnO NPs exhibits a potent activity against gram positive and gram negative bacteria.

  16. Airborne ammonia and ammonium within the Northern Adriatic area, Croatia.

    Science.gov (United States)

    Alebic-Juretic, Ana

    2008-08-01

    Determination of airborne ammonia started in the early 1980s, as a part of air pollution monitoring of industrial plants. Due to high emissions, the city of Rijeka was one of the most polluted in Croatia in the mid-1980s. Considerable reductions in SO2 and NO(x) emissions led to lower airborne levels of these pollutants in the mid 1990s. In spite of the coke plant closure in 1994, there was only a weak decline in airborne ammonia over the period 1980--2005, with annual means in the range of 12-20 microg m(-3) at urban Site 1 and 6-28 microg m(-3) at suburban Site 2. Similar behaviour has been observed with ammonium in bulk rainwater samples since 1996. Higher and approximately equal deposition of nitrogen as ammonium (N-NH4+) were obtained for the urban Site 1 and the mountainous Site 4, but with different causative facts. Ammonium's contribution to total nitrogen (NO3(-)+NH4+) deposition is approximately two thirds, even for a remote Site 3.

  17. Observations of atmospheric ammonia from TANSO-FTS/GOSAT

    Science.gov (United States)

    Someya, Yu; Imasu, Ryoichi; Saitoh, Naoko; Shiomi, Kei

    2017-04-01

    Atmospheric ammonia has large impacts on the nitrogen cycles or atmospheric environment such as nucleation of PM2.5 particles. It is reported that ammonia in the atmosphere has been increasing rapidly with the growth of population globally and this trend must continue in the future. Satellite observation is an effective approach to get to know the global perspectives of the gas. Atmospheric ammonia is observable using the thermal infrared (TIR) spectra, and IASI, TES and CrIS had been revealed those distributions. GOSAT also has TIR band including the ammonia absorption bands. GOSAT has the shorter revisit cycle than that of the other hyper-spectral TIR sounders mentioned above, therefore, the shorter time-scale events can be represented. In addition to the importance of the impacts of ammonia itself, the concentration ratio between ammonia and the other trace gases such as CO which is one of the main targets of the GOSAT-2 project is useful as the indicator of their emission sources. In this study, we introduce an algorithm to retrieve the column amount of atmospheric ammonia based on non-linear optimal estimation (Rogers, 2000) from GOSAT spectra in the ammonia absorption band between 960 - 970 cm-1. Temperature and water vapor profiles are estimated in advance of the ammonia retrieval. The preliminary results showed significant high concentrations of ammonia in the Northern India and the Eastern China as pointed out in the previous researches. We will discuss the global distribution of ammonia in the presentation.

  18. Clustering of Emerging Flux

    Science.gov (United States)

    Ruzmaikin, A.

    1997-01-01

    Observations show that newly emerging flux tends to appear on the Solar surface at sites where there is flux already. This results in clustering of solar activity. Standard dynamo theories do not predict this effect.

  19. Pretreatment of Biomass by Aqueous Ammonia for Bioethanol Production

    Science.gov (United States)

    Kim, Tae Hyun; Gupta, Rajesh; Lee, Y. Y.

    The methods of pretreatment of lignocellulosic biomass using aqueous ammonia are described. The main effect of ammonia treatment of biomass is delignification without significantly affecting the carbohydrate contents. It is a very effective pretreatment method especially for substrates that have low lignin contents such as agricultural residues and herbaceous feedstock. The ammonia-based pretreatment is well suited for simultaneous saccharification and co-fermentation (SSCF) because the treated biomass retains cellulose as well as hemicellulose. It has been demonstrated that overall ethanol yield above 75% of the theoretical maximum on the basis of total carbohydrate is achievable from corn stover pretreated with aqueous ammonia by way of SSCF. There are two different types of pretreatment methods based on aqueous ammonia: (1) high severity, low contact time process (ammonia recycle percolation; ARP), (2) low severity, high treatment time process (soaking in aqueous ammonia; SAA). Both of these methods are described and discussed for their features and effectiveness.

  20. Burnout in a channel with non-uniform circumferential heat flux

    International Nuclear Information System (INIS)

    Lee, D.H.

    1966-03-01

    Burnout experiments are reported for uniform flux and circumferential flux tilt (maximum/average flux about 1.25) with tubes and annuli, all the experiments having uniform axial heating. These show similar results, the burnout power with flux tilt being within 10% of that with uniform flux. For the same mean exit steam quality, the local maximum flux is higher than the predicted burnout value and generally a better prediction is obtained using the average flux. (author)

  1. Kinetics of hydrogen release from dissolutions of ammonia borane in different ionic liquids

    International Nuclear Information System (INIS)

    Valero-Pedraza, María José; Martín-Cortés, Alexandra; Navarrete, Alexander; Bermejo, María Dolores; Martín, Ángel

    2015-01-01

    Ammonia borane is a promising hydrogen storage material that liberates hydrogen by thermolysis at moderate temperatures, but it also presents major limitations for practical applications including a long induction time before the initiation of hydrogen release and a difficult regeneration. Previous works have demonstrated that by dissolution of ammonia borane into several ionic liquids, and particularly in 1-butyl-3-methylimidazolium chloride bmimCl, the induction period at the beginning of the thermolysis is eliminated, but some problems persist, including foaming and the formation of a residue after thermolysis that is insoluble in the ionic liquid. In this work, the release of hydrogen from ammonia borane dissolved in different ionic liquids has been analyzed, measuring the kinetics of hydrogen release, visually following the evolution of the sample during the process using pressure glass tube reactors, and analyzing the residue by spectroscopic techniques. While dissolutions of ammonia borane in most ionic liquids analyzed show similar properties as dissolutions in bmimCl, using ionic liquids with bis(trifluoromethylsulfanyl)imide Tf 2 N anion the foaming problem is reduced, and in some cases the residue remains dissolved in the ionic liquid, while with ionic liquids with choline anion higher hydrogen yields are achieved that indicate that the decomposition of ammonia borane proceeds through a different path. - Highlights: • Hydrogen release from ammonia borane dissolved in 13 ionic liquids has been studied. • Induction time is shortened and hydrogen release rate is accelerated in all cases. • The best results are obtained using ionic liquids with Tf 2 N anion. • Ch cation ionic liquids enable higher H 2 yield, but cyclotriborazane is produced.

  2. THE STRIPPING OF AMMONIA FROM LANDFILL LEACHATE IN PLUG FLOW REACTORS

    Directory of Open Access Journals (Sweden)

    Danuza Costa Campos

    2010-10-01

    Full Text Available The leachate is a highly liquid polluting, considering, besides high concentrations of ammonia nitrogen. Treating leachate is a very difficult task once its composition is very complex. A king of treatment that is being developed is the stripping of ammonia where this chemical will be removed from the leachate by mass transfer of the liquid phase to gas. Therefore, this paper addressed to study the ammonia stripping process in leachates liquids using plug-flow reactors in series. In order to accomplish the experimental part four plugflow reactors in series were build, with an average height of 50 centimeters, without forced air supplier and without leachate pH adjustment. The leachate sample used was from the metropolitan landfill of Joao Pessoa city, which was collected and transported to the EXTRABES laboratory and made the physicochemical characterization. The experimental monitoring system consisted of four distinct phases, with applied superficial loads of 450, 500, 600 and 700 kg NH4+ ha-1 day-1, hydraulic detention time equal to 65, 60, 50 and 38 days, and it was obtained an average efficiency of ammonia nitrogen removal around 96.1%, 99.7%, 99.5% and 98.5% respectively. It was found that the removal efficiency of NH3 was satisfactory in all phases, however, the kinetic study showed that the higher the surface charge applied to the reactors, the higher the rate constant for removal of NH3 stripping process. Thus we can conclude that the process of stripping ammonia from landfill leachate may be done in plug-flow reactors in series, with an average depth of 50 cm, due to provide high removal efficiency of ammonia nitrogen, with low operating costs.

  3. Submersible microbial desalination cell for simultaneous ammonia recovery and electricity production from anaerobic reactors containing high levels of ammonia

    DEFF Research Database (Denmark)

    Zhang, Yifeng; Angelidaki, Irini

    2015-01-01

    High ammonia concentration in anaerobic reactors can seriously inhibit the anaerobic digestion process. In this study, a submersible microbial desalination cell (SMDC) was developed as an innovative method to lower the ammonia level in a continuous stirred tank reactor (CSTR) by in situ ammonia...... and free NH3 diffusion were identified as the mechanisms responsible for the ammonia transportation. With an increase in initial ammonia concentration and a decrease in external resistance, the SMDC performance was enhanced. In addition, the coexistence of other cations in CSTR or cathode had no negative...

  4. Electrospun V2O5 composite fibers: Synthesis, characterization and ammonia sensing properties

    International Nuclear Information System (INIS)

    Modafferi, V.; Trocino, S.; Donato, A.; Panzera, G.; Neri, G.

    2013-01-01

    In the present work, vanadium oxide (V 2 O 5 ) fibers have been investigated for monitoring ammonia (NH 3 ) at ppb levels in air. A simple sol gel-based electrospinning process has been applied for the synthesis of vanadium oxide/polyvinyl acetate (PVAc) and vanadium oxide/polyvinylpyrrolidone (PVP) composite fibers. Composite fibers doped with platinum (Pt) have been also prepared. The pure and Pt-doped metal oxide phase has been subsequently obtained by removing the polymer binder at high temperature in air. The samples have been widely studied to characterize their morphological and microstructural properties by X-Ray Diffraction, Fourier Transform InfraRed spectroscopy, X-ray Photoelectron Spectroscopy, and Scanning Electron Microscopy investigations. The application of the produced fibers in highly sensitive ammonia resistive sensors has been demonstrated. The influence of the nature of polymer binder and platinum addition on the sensing performances of the V 2 O 5 fibers has been investigated and discussed.V 2 O 5 fibers produced by using PVP as a polymer binder have shown higher sensitivity toward ammonia at ppb concentrations than fibers obtained with PVAc. Pt-doped samples have shown a lower response compared to un-doped samples. - Highlights: • Synthesis of vanadium oxide composite fibers by electrospinning • Physical and chemical characterization of prepared samples • Investigation of the sensing properties to ppb concentrations of ammonia in air

  5. Ammonia observations of the molecular clouds near S68, S140, OMC2 and S106

    International Nuclear Information System (INIS)

    Little, L.T.; Brown, A.T.; Macdonald, G.H.; Riley, P.W.; Matheson, D.N.

    1980-01-01

    The J=1, K=1 and J=2, K=2 transitions of interstellar ammonia have been observed in the molecular clouds near S68, S140, OMC2 and S106. Maps of the ammonia emission obtained with a 2.2-arcmin beam are presented and compared with observations of other interstellar molecules, in particular carbon monoxide and formaldehyde. The distribution of the ammonia emission in OMC2 and S140 resembles more closely that of 2-mm formaldehyde than 13 CO, which is generally more extended. On the other hand, the densities of hydrogen molecules derived from the ammonia observations on the basis of a simple uniform-density model for the source are much lower than those obtained from 2-mm formaldehyde observations. This discrepancy may be resolved either by assuming a 'core-halo' or a 'clumped' structure for the source. The limits to 'halo' emission are used to suggest that the latter possibility is more probable, in which case the medium is well modelled as many clumps of density approximately 10 6 cm -3 and size -2 pc, immersed in a more tenuous medium of density approximately 10sup(3 to 4)cm -3 . (author)

  6. Temperature structure and emergent flux of the Jovian planets

    International Nuclear Information System (INIS)

    Silvaggio, P.; Sagan, C.

    1978-10-01

    Long path, low temperature, moderate resolution spectra of methane and ammonia, broadened by hydrogen and helium, are used to calculate non-gray model atmospheres for the four Jovian planets. The fundamental and first overtone of hydrogen contributes enough absorption to create a thermal inversion for each of the planets. The suite of emergent spectral fluxes and representative limb darkenings and brightenings are calculated for comparison with the Voyager infrared spectra. The temperature differences between Jovian belts and zones corresponds to a difference in the ammonia cirrus particle radii (1 to 3 micron in zones; 10 micron in belts). The Jovian tropopause is approximately at the 0.1 bar level. A thin ammonia cirrus haze should be distributed throughout the Saturnian troposphere; and NH3 gas must be slightly supersaturated or ammonia ice particles are carried upwards convectively in the upper troposphere of Saturn. Substantial methane clouds exist on both Uranus and Neptune. There is some evidence for almost isothermal structures in the deep atmospheres of these two planets

  7. Ammonia in London: is it increasing and what is the relevance of urban ammonia for air quality impacts?

    Science.gov (United States)

    Braban, Christine; Tang, Sim; Poskitt, Janet; Van Dijk, Netty; Leeson, Sarah; Dragosits, Ulli; Hutchings, Torben; Twigg, Marsailidh; Di Marco, Chiara; Langford, Ben; Tremper, Anja; Nemitz, Eiko; Sutton, Mark

    2017-04-01

    Emissions of ammonia affect both rural and urban air quality primarily via reaction of ammonia in the atmosphere forming secondary ammonium salts in particulate matter (PM). Urban ammonia emissions come from a variety of sources including biological decomposition, human waste, industrial processes and combustion engines. In the UK, the only long-term urban ammonia measurement is a UK National Ammonia Monitoring Network site at London Cromwell Road, recording monthly average concentrations. Short term measurements have also been made in the past decade at Marylebone Road, North Kensington and on the BT Tower. Cromwell Road is a kerbside site operational since 1999. The Cromwell Road data indicates that ammonia concentrations may be increasing since 2010-2012 after a long period of decreasing. Data from the National Atmospheric Emissions Inventory indicates ammonia emissions from diesel fleet exhausts increasing over this time period but an overall net decrease in ammonia emissions. With changes in engine and exhaust technology to minimise pollutant emissions and the importance of ammonia as a precursor gas for secondary PM, there is a challenge to understand urban ammonia concentrations and subsequent impacts on urban air quality. In this paper the long term measurements are assessed in conjunction with the short-term measurements.The challenges to assess the relative importance of local versus long range ammonia emission are discussed.

  8. Reversible intercalation of ammonia molecules into a layered double hydroxide structure without exchanging nitrate counter-ions

    International Nuclear Information System (INIS)

    Carbajal Arizaga, Gregorio Guadalupe; Wypych, Fernando; Castillon Barraza, Felipe; Contreras Lopez, Oscar Edel

    2010-01-01

    A zinc/aluminum LDH was precipitated with recycled ammonia from a chemical vapor deposition reaction. The LDH presented a crystalline phase with basal distance of 8.9 A, typical for nitrate-containing LDHs, and another phase with a basal distance of 13.9 A. Thermal treatment at 150 o C eliminated the phase with the bigger basal distance leaving only the anhydrous nitrate-intercalated LDH structure with 8.9 A. Intense N-H stretching modes in the FTIR spectra suggested that the expansion was due to intercalation of ammonia in the form of [NH 4 (NH 3 ) n ] + species. When additional samples were precipitated with pure ammonia, the conventional LDH nitrate structure was obtained (8.9 A basal distance) at pH=7, as well as a pure crystalline phase with 13.9 A basal distance at pH=10 due to ammonia intercalation that can be removed by heating at 150 o C or by stirring in acetone, confirming a unusual sensu stricto intercalation process into a LDH without exchanging nitrate ions. - Graphical abstract: LDH-nitrate precipitated with ammonia expands the interlayer space if ammonia is bubbled up to pH 10. The basal distance decreased when the compound was heated at 150 o C or stirred in acetone. Nitrate ions are not exchanged.

  9. Ammonia Synthesis using Ti and Nb Nitride Nano-particles Prepared by Mesoporous Graphitic C3N4

    KAUST Repository

    Kumagai, Hiromu

    2015-01-22

    TiN and NbN nanoparticles were synthesized from mesoporous graphitic C3N4 (mpg-C3N4) as a reactive template and used as the catalyst for ammonia synthesis. The obtained TiN and NbN nanoparticles possess high surface areas of 299 and 275 m2 g-1, respectively, making them attractive in the use of catalysis and support. Although most of the TiN and NbN particles show no measurable activity for ammonia formation, the nanoparticles enabled an ammonia synthesis rate of 31 μmol h-1 g-cat-1 at 673 K and 0.1 MPa of synthesis gas (N2 + 3H2) for both TiN and NbN catalysts. It is evident that the formation of nanoparticles with high nitride surface area is essential for the materials to function as catalysts in ammonia synthesis. The addition of Fe to TiN enhanced the ammonia synthesis activity, whereas it had detrimental effects on the catalytic activity of NbN. The properties of these catalysts in ammonia synthesis are discussed.

  10. Innovative bioelectrochemical-anaerobic-digestion integrated system for ammonia recovery and bioenergy production from ammonia-rich residues

    DEFF Research Database (Denmark)

    Zhang, Yifeng; Angelidaki, Irini

    2015-01-01

    Ammonia (NH4+/NH3) inhibition during anaerobic digestion process is one of the most frequent problems existing in biogas plants, resulting in unstable process and reduced biogas production. In this study, we developed a novel hybrid system, consisted of a submersed microbial resource recovery cell...... (SMRC) and a continuous stirred tank reactor (CSTR), to prevent ammonia toxicity during anaerobic digestion by in-situ ammonia recovery and electricity production (Figure 1). In batch experiment, the ammonia concentration in the CSTR decreased from 6 to 0.7 g-N/L with an average recovery rate of 0.18 g...... of ammonia recovery on the microbial community composition in the integrated system. Results clearly indicate the great potential of the SMRC-CSTR-coupled system for efficient and cost-effective ammonia recovery, energy production and treatment of ammonia-rich residues....

  11. Growth at low ammonium concentrations and starvation response as potential factors involved in niche differentiation among ammonia-oxidizing bacteria.

    Science.gov (United States)

    Bollmann, Annette; Bär-Gilissen, Marie-José; Laanbroek, Hendrikus J

    2002-10-01

    In nature, ammonia-oxidizing bacteria have to compete with heterotrophic bacteria and plants for limiting amounts of ammonium. Previous laboratory experiments conducted with Nitrosomonas europaea suggested that ammonia-oxidizing bacteria are weak competitors for ammonium. To obtain a better insight into possible methods of niche differentiation among ammonia-oxidizing bacteria, we carried out a growth experiment at low ammonium concentrations with N. europaea and the ammonia oxidizer G5-7, a close relative of Nitrosomonas oligotropha belonging to Nitrosomonas cluster 6a, enriched from a freshwater sediment. Additionally, we compared the starvation behavior of the newly enriched ammonia oxidizer G5-7 to that of N. europaea. The growth experiment at low ammonium concentrations showed that strain G5-7 was able to outcompete N. europaea at growth-limiting substrate concentrations of about 10 micro M ammonium, suggesting better growth abilities of the ammonia oxidizer G5-7 at low ammonium concentrations. However, N. europaea displayed a more favorable starvation response. After 1 to 10 weeks of ammonium deprivation, N. europaea became almost immediately active after the addition of fresh ammonium and converted the added ammonium within 48 to 96 h. In contrast, the regeneration time of the ammonia oxidizer G5-7 increased with increasing starvation time. Taken together, these results provide insight into possible mechanisms of niche differentiation for the ammonia-oxidizing bacteria studied. The Nitrosomonas cluster 6a member, G5-7, is able to grow at ammonium concentrations at which the growth of N. europaea, belonging to Nitrosomonas cluster 7, has already ceased, providing an advantage in habitats with continuously low ammonium concentrations. On the other hand, the ability of N. europaea to become active again after longer periods of starvation for ammonium may allow better exploitation of irregular pulses of ammonium in the environment.

  12. EFFECTIVE HYPERFINE-STRUCTURE FUNCTIONS OF AMMONIA

    International Nuclear Information System (INIS)

    Augustovičová, L.; Soldán, P.; Špirko, V.

    2016-01-01

    The hyperfine structure of the rotation-inversion ( v 2 = 0 + , 0 − , 1 + , 1 − ) states of the 14 NH 3 and 15 NH 3 ammonia isotopomers is rationalized in terms of effective (ro-inversional) hyperfine-structure (hfs) functions. These are determined by fitting to available experimental data using the Hougen’s effective hyperfine-structure Hamiltonian within the framework of the non-rigid inverter theory. Involving only a moderate number of mass independent fitting parameters, the fitted hfs functions provide a fairly close reproduction of a large majority of available experimental data, thus evidencing adequacy of these functions for reliable prediction. In future experiments, this may help us derive spectroscopic constants of observed inversion and rotation-inversion transitions deperturbed from hyperfine effects. The deperturbed band centers of ammonia come to the forefront of fundamental physics especially as the probes of a variable proton-to-electron mass ratio.

  13. Computational Search for Improved Ammonia Storage Materials

    DEFF Research Database (Denmark)

    Jensen, Peter Bjerre; Lysgaard, Steen; Vegge, Tejs

    , bromide or iodide, and mixtures thereof. In total the search space consists of thousands of combinations, which makes a GA ideal, to reduce the number of necessary calculations. We are screening for a one step release from either a hexa or octa ammine, and we have found promising candidates, which......Metal halide ammines, e.g. Mg(NH3)6Cl2 and Sr(NH3)8Cl2, can reversibly store ammonia, with high volumetric hydrogen storage capacities. The storage in the halide ammines is very safe, and the salts are therefore highly relevant as a carbon-free energy carrier in future transportation infrastructure....... In this project we are searching for improved mixed materials with optimal desorption temperatures and kinetics, optimally releasing all ammonia in one step. We apply Density Functional Theory, DFT, calculations on mixed compounds selected by a Genetic Algorithm (GA), relying on biological principles of natural...

  14. Experimental and numerical study of ammonia combustion

    OpenAIRE

    Duynslaegher, Catherine

    2011-01-01

    The problems of oil resources and CO2 emissions becoming increasingly alarming, the search for alternatives to fossil fuels is an important concern of our society. Even though hydrogen has been recognized as a promising fuel, implementing a global hydrogen-based economy is at present a non-feasible approach unless a suitable storage medium could be found. To bypass such difficulties, the use of ammonia in a modified spark ignition engine has been suggested. Since hydrogen must still be produc...

  15. Diverse microbial species survive high ammonia concentrations

    Science.gov (United States)

    Kelly, Laura C.; Cockell, Charles S.; Summers, Stephen

    2012-04-01

    Planetary protection regulations are in place to control the contamination of planets and moons with terrestrial micro-organisms in order to avoid jeopardizing future scientific investigations relating to the search for life. One environmental chemical factor of relevance in extraterrestrial environments, specifically in the moons of the outer solar system, is ammonia (NH3). Ammonia is known to be highly toxic to micro-organisms and may disrupt proton motive force, interfere with cellular redox reactions or cause an increase of cell pH. To test the survival potential of terrestrial micro-organisms exposed to such cold, ammonia-rich environments, and to judge whether current planetary protection regulations are sufficient, soil samples were exposed to concentrations of NH3 from 5 to 35% (v/v) at -80°C and room temperature for periods up to 11 months. Following exposure to 35% NH3, diverse spore-forming taxa survived, including representatives of the Firmicutes (Bacillus, Sporosarcina, Viridibacillus, Paenibacillus, Staphylococcus and Brevibacillus) and Actinobacteria (Streptomyces). Non-spore forming organisms also survived, including Proteobacteria (Pseudomonas) and Actinobacteria (Arthrobacter) that are known to have environmentally resistant resting states. Clostridium spp. were isolated from the exposed soil under anaerobic culture. High NH3 was shown to cause a reduction in viability of spores over time, but spore morphology was not visibly altered. In addition to its implications for planetary protection, these data show that a large number of bacteria, potentially including spore-forming pathogens, but also environmentally resistant non-spore-formers, can survive high ammonia concentrations.

  16. Ammonia volatilization from sows on grassland

    Science.gov (United States)

    Sommer, S. G.; Søgaard, H. T.; Møller, H. B.; Morsing, S.

    According to regulations, sows with piglets on organic farms must graze on pastures. Volatilization of ammonia (NH 3) from urine patches may represent a significant source of nitrogen (N) loss from these farms. Inputs of N are low on organic farms and losses may reduce crop production. This study examined spatial variations in NH 3 volatilization using a movable dynamic chamber, and the pH and total ammoniacal nitrogen (TAN) content in the topsoil of pastures with grazing sows was measured during five periods between June 1998 and May 1999. Gross NH 3 volatilization from the pastures was also measured with an atmospheric mass balance technique during seven periods from September 1997 until June 1999. The dynamic chamber study showed a high variation in NH 3 volatilization because of the distribution of urine; losses were between 0 and 2.8 g NH 3-N m -2 day -1. Volatilization was highest near the feeding area and the huts, where the sows tended to urinate. Ammonia volatilization rate was linearly related to the product of NH 3 concentration in the boundary layer and wind speed. The NH 3 in the boundary layer was in equilibrium with NH 3 in soil solution. Gross NH 3 volatilization was in the range 0.07-2.1 kg NH 3-N ha -1 day -1 from a pasture with 24 sows ha -1. Ammonia volatilization was related to the amount of feed given to the sows, incident solar radiation and air temperature during measuring periods, and also to temperature, incident solar radiation and rain 1-2 days before measurements. Annual ammonia loss was 4.8 kg NH 3-N sow -1.

  17. Nitrocarburising in ammonia-hydrocarbon gas mixtures

    DEFF Research Database (Denmark)

    Pedersen, Hanne; Christiansen, Thomas; Somers, Marcel A. J.

    2010-01-01

    The present work investigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammoniapropene- hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere...... microscopy and X-ray diffraction analysis. It is shown that the use of unsaturated hydrocarbon gas in nitrocarburising processes is a viable alternative to traditional nitrocarburising methods....

  18. Ammonia Signaling in Yeast Colony Formation

    Czech Academy of Sciences Publication Activity Database

    Palková, Z.; Váchová, Libuše

    2003-01-01

    Roč. 225, - (2003), s. 229-272 ISSN 0074-7696 R&D Projects: GA ČR GA204/02/0650 Grant - others:GA of Charles University(CZ) 141/2001/B-BIO/PrF and EMBO YIP for ZP Institutional research plan: CEZ:MSM 113100003 Keywords : yeast colonies * ammonia * ammonium Subject RIV: EE - Microbiology, Virology Impact factor: 4.286, year: 2003

  19. Ammonia biofiltration and community analysis of ammonia-oxidizing bacteria in biofilters.

    Science.gov (United States)

    Jun, Yin; Wenfeng, Xu

    2009-09-01

    Biological removal of ammonia was investigated using compost and sludge as packing materials in laboratory-scale biofilters. The aim of this study is to characterize the composition of ammonia-oxidizing bacteria (AOB) in two biofilters designed to remove ammonia. Experimental tests and measurements included analysis of removal efficiency and metabolic products. The inlet concentration of ammonia applied was 20-100 mg m(-3). Removal efficiencies of BFC and BFS were in the range of 97-99% and 95-99%, respectively. Periodic analysis of the biofilter packing materials showed ammonia was removed from air stream by nitrification and by the improved absorption of NH(3) in the resultant acidity. Nitrate was the dominant product of NH(3) transformation. Changes in the composition of AOB were examined by using nested PCR, denaturing gradient gel electrophoresis (DGGE) and sequencing of DGGE bands. DGGE analysis of biofilter samples revealed that shifts in the community structure of AOB were observed in the experiment; however, the idle phase did not cause the structural shift of AOB. Phylogenetic analysis revealed the population of AOB showed Nitrosospira sp. remains the predominant population in BFC, while Nitrosomonas sp. is the predominant population in BFS.

  20. Development, characterization, and validation of an optical transfer standard for ammonia in air

    Science.gov (United States)

    Lüttschwager, Nils; Balslev-Harder, David; Leuenberger, Daiana; Pogány, Andrea; Werhahn, Olav; Ebert, Volker

    2017-04-01

    OTS from 1 ppb to 200 ppb. We found the results obtained with the OTS to be concordant to reference gas mixtures yielding amount fraction results with standard uncertainties of less than 3 %, for which an uncertainty budget is provided. Acknowledgement: This work was supported by the European Metrology Research Programme (EMRP). The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union. References 1. A. Pogány, O. Werhahn, and V. Ebert, High-Accuracy Ammonia Line Intensity Measurements at 1.5 µm, in Imaging and Applied Optics 2016, OSA Technical Digest (online) (Optical Society of America, 2016), paper JT3A.15, DOI: 10.1364/3D.2016.JT3A.15

  1. Peripheral Ammonia as a Mediator of Methamphetamine Neurotoxicity

    Science.gov (United States)

    Halpin, Laura E.; Yamamoto, Bryan K.

    2012-01-01

    Ammonia is metabolized by the liver and has established neurological effects. The current study examined the possibility that ammonia contributes to the neurotoxic effects of methamphetamine (METH). The results show that a binge dosing regimen of METH to the rat increased plasma and brain ammonia concentrations that were paralleled by evidence of hepatotoxicity. The role of peripheral ammonia in the neurotoxic effects of METH was further substantiated by the demonstration that the enhancement of peripheral ammonia excretion blocked the increases in brain and plasma ammonia and attenuated the long term depletions of dopamine and serotonin typically produced by METH. Conversely, the localized perfusion of ammonia in combination with METH, but not METH alone or ammonia alone, into the striatum recapitulated the neuronal damage produced by the systemic administration of METH. Furthermore, this damage produced by the local administration of ammonia and METH was blocked by the GYKI 52466, an AMPA receptor antagonist. These findings highlight the importance of ammonia derived from the periphery as a small molecule mediator of METH neurotoxicity and more broadly emphasize the importance of peripheral organ damage as a possible mechanism that mediates the neuropathology produced by drugs of abuse and other neuroactive molecules. PMID:22993432

  2. Ammonia recovery from anaerobically digested cattle manure by steam stripping.

    Science.gov (United States)

    Zeng, L; Mangan, C; Li, X

    2006-01-01

    Ammonia recovery from anaerobically digested cattle manure effluents through steam stripping was studied at a stripping tower temperature of 98-99 degrees C and a steam-water ratio approximately 56-72 g/L. The digested manure effluents were first treated by microfiltration and then the permeate was used as feed in steam stripping. The stripping performance was evaluated under different feed pH values, ammonia concentrations and temperatures. The increase of the initial feed pH does not significantly improve ammonia stripping efficiency due to the fact that the stripped effluent pH is increased during steam stripping. This suggests that steam stripping of anaerobically digested manure effluents for ammonia recovery may not need pre-raised pH. In contrast, the pH value of the synthetic ammonia wastewater containing NH4Cl dramatically decreases after steam stripping. Increasing the feed temperature slightly improves ammonia stripping efficiency, but reduces the concentration of the recovered ammonia in the condensate due to an increased condensate volume at a higher feed temperature. Therefore, the feed temperature should be controlled at an optimum point that can compromise the condensate ammonia concentration and the ammonia stripping efficiency. Experimental results indicate that recovery of ammonia from anaerobically digested cattle manure effluents as NH4OH is technically feasible.

  3. Dynamics of the Ammonia Laser

    Science.gov (United States)

    White, Jonathon David

    An experimental and theoretical study of the dynamics of NH_3 lasers is presented. The significant achievements of this work are summarized below. In initial experiments, a pulsed transversely -excited CO_2 laser operating on the 9R(30) transition is used to optically pump mixtures of NH_3 in buffer gas. A simple oscillator/amplifier system allows the performance of the NH_3 amplifier in the 11 μm region to be characterized. Small-signal gain coefficients of >10%/cm are measured on the aQ(3,3) transition at 10.8 mum, while pump conversion efficiencies of ~ 50% are shown to occur under saturation conditions. The NH_3 laser system is described by a rate-equation model, which is validated by comparison with experiment over a wide range of operating conditions. Measurements are made for NH_3 concentrations ranging from 0.05 to 0.2%, for Ar, N_2 and He buffer gas pressures from 170 to 700 Torr, and for gas temperatures from 200 to 300 K. Optically pumped NH _3 is shown to be a versatile and efficient system for the amplification of mid-infrared radiation. The rate-equation model is used to aid in the design of a simple and efficient NH_3 laser. This laser is tuned over more than 70 vibrational band transitions between 10.08 and 14.14 mu m. Output energies greater than 1 J per pulse are achieved on several of the strongest lines. In a non-selective cavity an energy conversion efficiency of greater than 35% is obtained with a maximum output energy of 4.6 J. Optically pumped NH_3 is shown to be a flexible and efficient system for the downconversion of CO _2 radiation to the 10-14 mu m region. In other experiments, it is shown that optically pumped high pressure mixtures of NH_3 in N_2 are efficient, broadband amplifiers of pulsed CO_2 radiation. In a dilute NH_3 mixture at 6 atmospheres and 200 K, a single pass gain of 150 (21.8 dB) is measured for the 10P(34) CO_2 transition. Gain is observed in NH_3 at pressures as high as 10 atmospheres. Experimental measurements are

  4. On the analysis of para-ammonia observations

    Science.gov (United States)

    Kuiper, T. B. H.

    1994-01-01

    The intensities and optical depths of the (1, 1), (2, 2), and (2, 1) inversion transitions of ammonia can be calculated quite accurately without solving the equations of statistical equilibrium. A two-temperature partition function suffices. The excitation of the K-ladders can be approximated by using a temperature obtained from a two-level model with the (2, 1) and (1, 1) levels. Distribution of populations between the ladders is described with the kinetic temperature. This enables one to compute the (1, 1) and (2, 1) inversion transition excitation temperatures and optical depths. To compute the (2, 2) brightness temperatures, the fractional population of the (2, 2) doublet is computed from the population of the (1, 1) doublet using the 'true rotation temperature,' which is calculated using a three-level model with the (2, 1), (2, 2), and (1, 1) levels. In spite of some iterative steps, the calculation is quite fast.

  5. Automated region definition for cardiac nitrogen-13-ammonia PET imaging.

    Science.gov (United States)

    Muzik, O; Beanlands, R; Wolfe, E; Hutchins, G D; Schwaiger, M

    1993-02-01

    In combination with PET, the tracer 13N-ammonia can be employed for the noninvasive quantification of myocardial perfusion at rest and after pharmacological stress. The purpose of this study was to develop an analysis method for the quantification of regional myocardial blood flow in the clinical setting. The algorithm includes correction for patient motion, an automated definition of multiple regions and display of absolute flows in polar map format. The effects of partial volume and blood to tissue cross-contamination were accounted for by optimizing the radial position of regions to meet fundamental assumptions of the kinetic model. In order to correct for motion artifacts, the myocardial displacement was manually determined based on edge-enhanced images. The obtained results exhibit the capability of the presented algorithm to noninvasively assess regional myocardial perfusion in the clinical environment.

  6. An alternative method for the measurement of neutron flux

    Indian Academy of Sciences (India)

    Here, the neutron flux inferred from the neutron count rate obtained with R-12 SDD shows an excellent agreement with the flux inferred from the neutron dose rate in a non-dissipative medium. Keywords. Neutron dose; neutron flux; superheated droplet detector; bubble nucleation. PACS Nos 29.40.Rg; 29.40.–n; 29.25.Dz. 1.

  7. Dis-aggregation of airborne flux measurements using footprint analysis

    NARCIS (Netherlands)

    Hutjes, R.W.A.; Vellinga, O.S.; Gioli, B.; Miglietta, F.

    2010-01-01

    Aircraft measurements of turbulent fluxes are generally being made with the objective to obtain an estimate of regional exchanges between land surface and atmosphere, to investigate the spatial variability of these fluxes, but also to learn something about the fluxes from some or all of the land

  8. An alternative method for the measurement of neutron flux

    Indian Academy of Sciences (India)

    Abstract. A simple and easy method for measuring the neutron flux is presented. This paper deals with the experimental verification of neutron dose rate–flux relationship for a non-dissipative medium. Though the neutron flux cannot be obtained from the dose rate in a dissipative medium, experimental result shows that for ...

  9. An alternative method for the measurement of neutron flux

    Indian Academy of Sciences (India)

    A simple and easy method for measuring the neutron flux is presented. This paper deals with the experimental verification of neutron dose rate–flux relationship for a non-dissipative medium. Though the neutron flux cannot be obtained from the dose rate in a dissipative medium, experimental result shows that for ...

  10. Properties of Flux Tubes and the Relation with Solar Irradiance ...

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... At the solar surface the magnetic field is bundled into discrete elements of concentrated flux, often referred to as magnetic flux tubes, which cover only a small fraction of the solar surface. Flux tubes span a whole spectrum of sizes, ranging from sunspots to features well below the best currently obtainable ...

  11. Ammonia determination in a roadway tunnel of the metropolitan area of Sao Paulo, Brazil

    Science.gov (United States)

    Vieira da Silva Filho, M.; Fornaro, A.; Pedrotti, J.; Ito, D.; Prado, Y.; Coelho, L. H. G.

    2012-04-01

    The degradation in air quality has been one of the most serious health problems afflicting the more than 19 million inhabitants of the metropolitan area of Sao Paulo (MASP). There are more than 7.5 million vehicles being 40% running with ethanol as fuel, 80% using a 3-way catalyst, and 15% being flex-fuel. This vehicular fleet is the main responsible for the air pollution problems, highlighting the aerosol. The different evaluations of the ionic composition of the aerosol and rainwater samples of the MASP showed the importance of the ammonium, from ammonia gas phase incorporated in liquid or solid atmospheric phase. Ammonia is the third most abundant nitrogen compound in the atmosphere, and whose global emissions are mainly from biogenic sources. Despite its short residence time it has a significant role influencing the acidity of cloud water and the formation of secondary aerosols. The purpose of this work is to evaluate the ammonia in urban area and in a roadway tunnel, with intense light vehicles traffic. The air sampling was carried out inside and outside the Janio Quadros roadway tunnel in MASP between 5 and 10 May, 2011 by using a simplified impinger system with 1.0 mmol L-1 H2SO4 solution, 1 L min-1 flux during 1 h. The ammonium measurements were carried out by a flow injection system using gas-diffusion and coupled contactless conductivity detection. The results point out that the number and the velocity of the vehicles influence on the ammonia concentration in both site sampling. The ammonia concentrations were twice higher inside the roadway tunnel, reaching the maximum value of 98 ?g m-3, with mean value of 48.1 (?15.4) ?g m-3. These data suggest that atmospheric ammonia is not only restricted to biogenic emissions, but also by vehicles in the MASP. Consequently, more regional assistance should be given to the sources of this compound, considering the increase of the megacities in the world and their effects on the global emissions.

  12. Effects of salt pond restoration on benthic flux: Sediment as a source of nutrients to the water column

    Science.gov (United States)

    Topping, Brent R.; Kuwabara, James S.; Carter, James L.; Garrettt, Krista K.; Mruz, Eric; Piotter, Sarah; Takekawa, John Y.

    2016-01-01

    Understanding nutrient flux between the benthos and the overlying water (benthic flux) is critical to restoration of water quality and biological resources because it can represent a major source of nutrients to the water column. Extensive water management commenced in the San Francisco Bay, Beginning around 1850, San Francisco Bay wetlands were converted to salt ponds and mined extensively for more than a century. Long-term (decadal) salt pond restoration efforts began in 2003. A patented device for sampling porewater at varying depths, to calculate the gradient, was employed between 2010 and 2012. Within the former ponds, the benthic flux of soluble reactive phosphorus and that of dissolved ammonia were consistently positive (i.e., moving out of the sediment into the water column). The lack of measurable nitrate or nitrite concentration gradients across the sediment-water interface suggested negligible fluxes for dissolved nitrate and nitrite. The dominance of ammonia in the porewater indicated anoxic sediment conditions, even at only 1 cm depth, which is consistent with the observed, elevated sediment oxygen demand. Nearby openestuary sediments showed much lower benthic flux values for nutrients than the salt ponds under resortation. Allochthonous solute transport provides a nutrient advective flux for comparison to benthic flux. For ammonia, averaged for all sites and dates, benthic flux was about 80,000 kg/year, well above the advective flux range of −50 to 1500 kg/year, with much of the variability depending on the tidal cycle. By contrast, the average benthic flux of soluble reactive phosphorus was about 12,000 kg/year, of significant magnitude, but less than the advective flux range of 21,500 to 30,000 kg/year. These benthic flux estimates, based on solute diffusion across the sediment-water interface, reveal a significant nutrient source to the water column of the pond which stimulates algal blooms (often autotrophic). This benthic source may be

  13. Kinetic model of ammonia synthesis in the solar nebula

    Science.gov (United States)

    Norris, T. L.

    1980-03-01

    Kinetic model of ammonia formation by iron catalysis in the primordial solar nebula is developed. The maximum time to reach equilibrium concentration is determined for various temperatures between 1000 and 200 K on the basis of reaction rates derived from industrial data on iron catalysts for ammonia. Application of the method for calculating the equilibrium time to an arbitrary nebula cooling model which maximizes the time available for ammonia synthesis results in an upper limit of 3% of the equilibrium value to the proportion of nitrogen in the form of ammonia at the time of planetary accretion, with ammonia abundance decreasing with distance from the sun. It is concluded that kinetic rather than equilibrium considerations control the abundance of ammonia in the solar nebula, and implications of the dominance of nitrogen for the evolution of the atmospheres of the terrestrial and Jovian planets and the composition of comets are indicated.

  14. Converting Wind Energy to Ammonia at Lower Pressure

    International Nuclear Information System (INIS)

    Malmali, Mahdi; Reese, Michael; McCormick, Alon V.; Cussler, E. L.

    2017-01-01

    Renewable wind energy can be used to make ammonia. However, wind-generated ammonia costs about twice that made from a traditional fossil-fuel driven process. To reduce the production cost, we replace the conventional ammonia condensation with a selective absorber containing metal halides, e.g., calcium chloride, operating at near synthesis temperatures. With this reaction-absorption process, ammonia can be synthesized at 20 bar from air, water, and wind-generated electricity, with rates comparable to the conventional process running at 150–300 bar. In our reaction-absorption process, the rate of ammonia synthesis is now controlled not by the chemical reaction but largely by the pump used to recycle the unreacted gases. The results suggest an alternative route to distributed ammonia manufacture which can locally supply nitrogen fertilizer and also a method to capture stranded wind energy as a carbon-neutral liquid fuel.

  15. Gas sensors for ammonia detection based on polyaniline-coated multi-wall carbon nanotubes

    International Nuclear Information System (INIS)

    He Lifang; Jia Yong; Meng Fanli; Li Minqiang; Liu Jinhuai

    2009-01-01

    Polyaniline-coated multi-wall carbon nanotubes (PANI-coated MWNTs) were prepared by in situ polymerization method. Field emission scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and thermogravimetric analysis were used to characterize the as-prepared PANI-coated MWNTs. Obtained results indicated that PANI was uniformly coated on MWNTs, and the thickness of the coatings can be controlled by changing the weight ratios of aniline monomer and MWNTs in the polymerization process. Sensors were fabricated by spin-coating onto pre-patterned electrodes, and ammonia gas sensing properties of the as-prepared PANI-coated MWNTs were studied. The results showed a good response and reproducibility towards ammonia at room temperature. In addition, PANI-coated MWNTs exhibited a linear response to ammonia in the range of 0.2-15 ppm. The effects of the thickness of PANI coatings on the gas sensing properties were also investigated in detail. The results suggest a potential application of PANI-coated MWNTs in gas sensor for detecting ammonia.

  16. Modeling of ammonia emission in the USA and EU countries using an artificial neural network approach.

    Science.gov (United States)

    Stamenković, Lidija J; Antanasijević, Davor Z; Ristić, Mirjana Đ; Perić-Grujić, Aleksandra A; Pocajt, Viktor V

    2015-12-01

    Ammonia emissions at the national level are frequently estimated by applying the emission inventory approach, which includes the use of emission factors, which are difficult and expensive to determine. Emission factors are therefore the subject of estimation, and as such they contribute to inherent uncertainties in the estimation of ammonia emissions. This paper presents an alternative approach for the prediction of ammonia emissions at the national level based on artificial neural networks and broadly available sustainability and economical/agricultural indicators as model inputs. The Multilayer Perceptron (MLP) architecture was optimized using a trial-and-error procedure, including the number of hidden neurons, activation function, and a back-propagation algorithm. Principal component analysis (PCA) was applied to reduce mutual correlation between the inputs. The obtained results demonstrate that the MLP model created using the PCA transformed inputs (PCA-MLP) provides a more accurate prediction than the MLP model based on the original inputs. In the validation stage, the MLP and PCA-MLP models were tested for ammonia emission predictions for up to 2 years and compared with a principal component regression model. Among the three models, the PCA-MLP demonstrated the best performance, providing predictions for the USA and the majority of EU countries with a relative error of less than 20%.

  17. Process model for ammonia volatilization from anaerobic swine lagoons incorporating varying wind speeds and biogas bubbling

    Science.gov (United States)

    Ammonia volatilization from treatment lagoons varies widely with the total ammonia concentration, pH, temperature, suspended solids, atmospheric ammonia concentration above the water surface, and wind speed. Ammonia emissions were estimated with a process-based mechanistic model integrating ammonia ...

  18. Calculation notes in support of ammonia releases from waste tank ventilation systems

    International Nuclear Information System (INIS)

    Wojdac, L.F.

    1996-01-01

    Ammonia is generated in waste tanks via the degradation of nitrogen compounds. The ammonia is released from the liquids by a mechanism which is dependent on temperature, pH, ionic strength and ammonia concentration. The release of ammonia to the environment occurs via diffusion of ammonia through a stagnant air mass and into the ventilation system

  19. 46 CFR 98.25-5 - How anhydrous ammonia may be carried.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false How anhydrous ammonia may be carried. 98.25-5 Section 98... Anhydrous Ammonia in Bulk § 98.25-5 How anhydrous ammonia may be carried. (a) Anhydrous ammonia shall be..., except as otherwise provided in paragraph (b) of this section. (b) When anhydrous ammonia is to be...

  20. Upwind impacts of ammonia from an intensive poultry unit

    International Nuclear Information System (INIS)

    Jones, L.; Nizam, M.S.; Reynolds, B.; Bareham, S.; Oxley, E.R.B.

    2013-01-01

    This study investigated potential ammonia impacts on a sand dune nature reserve 600 m upwind of an intensive poultry unit. Ammonia concentrations and total nitrogen deposition were measured over a calendar year. A series of ammonia and nitrogen exposure experiments using dune grassland species were conducted in controlled manipulations and in the field. Ammonia emissions from the intensive poultry unit were detected up to 2.8 km upwind, contributing to exceedance of critical levels of ammonia 800 m upwind and exceedance of critical loads of nitrogen 2.8 km upwind. Emissions contributed 30% of the total N load in parts of the upwind conservation site. In the nitrogen exposure experiments, plants showed elevated tissue nitrogen contents, and responded to ammonia concentrations and nitrogen deposition loads observed in the conservation site by increasing biomass. Estimated long-term impacts suggest an increase in the soil carbon pool of 9% over a 50-year timescale. -- Highlights: •Ammonia from a poultry unit can be detected 2.8 km upwind. •Ammonia caused exceedance of critical levels 800 m and critical loads 2.8 km upwind. •Dune grassland species utilised ammonia as a nutrient source. •Plant biomass increased at low levels of ammonia and total nitrogen deposition. •Soil C pools are predicted to increase by 9% over 50 years due to the excess ammonia. -- Ammonia from a poultry unit has upwind impacts, exceeding critical levels 800 m and critical loads 2.8 km upwind, and increasing biomass and tissue N of dune grassland species

  1. Procedures for the synthesis of ethylenediamine bisborane and ammonia borane

    Science.gov (United States)

    Ramachandran, Padi Veeraraghavan; Gagare, Pravin D.; Mistry, Hitesh; Biswas, Bidyut

    2017-01-03

    A method for synthesizing ammonia borane includes (a) preparing a reaction mixture in one or more solvents, the reaction mixture containing sodium borohydride, at least one ammonium salt, and ammonia; and (b) incubating the reaction mixture at temperatures between about 0.degree. C. to about room temperature in an ambient air environment under conditions sufficient to form ammonia borane. Methods for synthesizing ethylenediamine bisborane, and methods for dehydrogenation of ethylenediamine bisborane are also described.

  2. Effect of chamber enclosure time on soil respiration flux: A comparison of linear and non-linear flux calculation methods

    DEFF Research Database (Denmark)

    Kandel, Tanka P; Lærke, Poul Erik; Elsgaard, Lars

    2016-01-01

    -deployment fluxes by linear regression techniques. Thus, usually the cumulative flux curve becomes downward concave due to the decreased gas diffusion rate. Non-linear models based on biophysical theory usually fit to such curvatures and may reduce the underestimation of fluxes. In this study, we examined...... the effect of increasing chamber enclosure time on SR flux rates calculated using a linear, an exponential and a revised Hutchinson and Mosier model (HMR). Soil respiration rates were measured with a closed chamber in combination with an infrared gas analyzer. During SR flux measurements the chamber......) to obtain a range of fluxes with different shapes of flux curves. The linear method provided more stable flux results during short enclosure times (few min) but underestimated initial fluxes by 15–300% after 45 min deployment time. Non-linear models reduced the underestimation as average underestimation...

  3. Heat Flux Distribution of Antarctica Unveiled

    Science.gov (United States)

    Martos, Yasmina M.; Catalán, Manuel; Jordan, Tom A.; Golynsky, Alexander; Golynsky, Dmitry; Eagles, Graeme; Vaughan, David G.

    2017-11-01

    Antarctica is the largest reservoir of ice on Earth. Understanding its ice sheet dynamics is crucial to unraveling past global climate change and making robust climatic and sea level predictions. Of the basic parameters that shape and control ice flow, the most poorly known is geothermal heat flux. Direct observations of heat flux are difficult to obtain in Antarctica, and until now continent-wide heat flux maps have only been derived from low-resolution satellite magnetic and seismological data. We present a high-resolution heat flux map and associated uncertainty derived from spectral analysis of the most advanced continental compilation of airborne magnetic data. Small-scale spatial variability and features consistent with known geology are better reproduced than in previous models, between 36% and 50%. Our high-resolution heat flux map and its uncertainty distribution provide an important new boundary condition to be used in studies on future subglacial hydrology, ice sheet dynamics, and sea level change.

  4. Fast in situ airborne measurement of ammonia using a mid-infrared off-axis ICOS spectrometer.

    Science.gov (United States)

    Leen, J Brian; Yu, Xiao-Ying; Gupta, Manish; Baer, Douglas S; Hubbe, John M; Kluzek, Celine D; Tomlinson, Jason M; Hubbell, Mike R

    2013-09-17

    A new ammonia (NH3) analyzer was developed based on off-axis integrated cavity output spectroscopy. Its feasibility was demonstrated by making tropospheric measurements in flights aboard the Department of Energy Gulfstream-1 aircraft. The ammonia analyzer consists of an optical cell, quantum-cascade laser, gas sampling system, control and data acquisition electronics, and analysis software. The NH3 mixing ratio is determined from high-resolution absorption spectra obtained by tuning the laser wavelength over the NH3 fundamental vibration band near 9.67 μm. Excellent linearity is obtained over a wide dynamic range (0-101 ppbv) with a response rate (1/e) of 2 Hz and a precision of ±90 pptv (1σ in 1 s). Two research flights were conducted over the Yakima Valley in Washington State. In the first flight, the ammonia analyzer was used to identify signatures of livestock from local dairy farms with high vertical and spatial resolution under low wind and calm atmospheric conditions. In the second flight, the analyzer captured livestock emission signals under windy conditions. Our results demonstrate that this new ammonia spectrometer is capable of providing fast, precise, and accurate in situ observations of ammonia aboard airborne platforms to advance our understanding of atmospheric compositions and aerosol formation.

  5. FIRST DETECTION OF AMMONIA IN THE LARGE MAGELLANIC CLOUD: THE KINETIC TEMPERATURE OF DENSE MOLECULAR CORES IN N 159 W

    International Nuclear Information System (INIS)

    Ott, Juergen; Henkel, Christian; Weiss, Axel; Staveley-Smith, Lister

    2010-01-01

    The first detection of ammonia (NH 3 ) is reported from the Magellanic Clouds. Using the Australia Telescope Compact Array, we present a targeted search for the (J, K) = (1,1) and (2,2) inversion lines toward seven prominent star-forming regions in the Large Magellanic Cloud (LMC). Both lines are detected in the massive star-forming region N 159 W, which is located in the peculiar molecular ridge south of 30 Doradus, a site of extreme star formation strongly influenced by an interaction with the Milky Way halo. Using the ammonia lines, we derive a kinetic temperature of ∼16 K, which is 2-3 times below the previously derived dust temperature. The ammonia column density, averaged over ∼17'', is ∼6 x 10 12 cm -2 ( 13 cm -2 over 9'' in the other six sources) and we derive an ammonia abundance of ∼4 x 10 -10 with respect to molecular hydrogen. This fractional abundance is 1.5-5 orders of magnitude below those observed in Galactic star-forming regions. The nitrogen abundance in the LMC (∼10% solar) and the high UV flux, which can photo-dissociate the particularly fragile NH 3 molecule, both must contribute to the low fractional NH 3 abundance, and we likely only see the molecule in an ensemble of the densest, best shielded cores of the LMC.

  6. Effect of atmospheric ammonia on laying hen performance

    Energy Technology Data Exchange (ETDEWEB)

    Deaton, J.W.; Reece, F.N.; Lott, B.D.

    1982-09-01

    In periods of extremely cold weather, energy conservation in a pit-type laying house usually results in a restricted ventilation rate and an increase in air pollutants particularly ammonia. Results show that 200 ppm ammonia for 17 days causes a significant loss in percent egg production and the hens lose a significant amount of weight with a reduced feed intake. Although not satisfactory, it appears that lesser amounts of ammonia (100 ppm) can be tolerated for short periods without an immediate drastic loss in laying performance if a choice has to be made between frozen waterers and cold stress versus atmospheric ammonia in the laying house.

  7. Ammonia transport in the kidney by Rhesus glycoproteins

    Science.gov (United States)

    Verlander, Jill W.

    2014-01-01

    Renal ammonia metabolism is a fundamental element of acid-base homeostasis, comprising a major component of both basal and physiologically altered renal net acid excretion. Over the past several years, a fundamental change in our understanding of the mechanisms of renal epithelial cell ammonia transport has occurred, replacing the previous model which was based upon diffusion equilibrium for NH3 and trapping of NH4+ with a new model in which specific and regulated transport of both NH3 and NH4+ across renal epithelial cell membranes via specific membrane proteins is required for normal ammonia metabolism. A major advance has been the recognition that members of a recently recognized transporter family, the Rhesus glycoprotein family, mediate critical roles in renal and extrarenal ammonia transport. The erythroid-specific Rhesus glycoprotein, Rh A Glycoprotein (Rhag), was the first Rhesus glycoprotein recognized as an ammonia-specific transporter. Subsequently, the nonerythroid Rh glycoproteins, Rh B Glycoprotein (Rhbg) and Rh C Glycoprotein (Rhcg), were cloned and identified as ammonia transporters. They are expressed in specific cell populations and membrane domains in distal renal epithelial cells, where they facilitate ammonia secretion. In this review, we discuss the distribution of Rhbg and Rhcg in the kidney, the regulation of their expression and activity in physiological disturbances, the effects of genetic deletion on renal ammonia metabolism, and the molecular mechanisms of Rh glycoprotein-mediated ammonia transport. PMID:24647713

  8. Release of ammonia from HAN-type PHA

    International Nuclear Information System (INIS)

    Zamecnik, J.R.

    1992-01-01

    A preliminary design basis for ammonia scrubbers in the DWPF has been issued. This design basis is based on a theoretical model of ammonia evolution from the SRAT, SME and RCT. It is desirable to acquire actual process data on ammonia evolution prior to performing detailed design of scrubbers for DWPF. The evolution of ammonia from the SRAT and SME in the Integrated DWPF Melter System (IDMS) was investigated during the HM4 run. In this run, Precipitate Hydrolysis Aqueous (PHA), which was made in the Precipitate Hydrolysis Experimental Facility (PHEF) using the HAN (hydroxylamine nitrate) process was used, thus resulting in PHA with a high concentration of ammonium ion

  9. Procedure for the in vitro determination of ammonia in blood

    International Nuclear Information System (INIS)

    Jung, K.; Faust, H.

    1985-01-01

    The invention has been aimed at a procedure for the in vitro determination of ammonia in blood based on microdiffusion and isotope dilution analysis. A definite quantity of blood serum has been mixed with a definite quantity of ammonium chloride labelled with the stable isotope 15 N. The mixture has been subjected to the microdiffusion (K 2 CO 3 additives and absorption of released ammonia in sulphuric acid). The ammonia bound in sulphuric acid has been devoted to a isotope analysis and the ammonia concentration of blood has been determined according to the isotope dilution analysis equation

  10. Ammonia pollution characteristics of centralized drinking water sources in China.

    Science.gov (United States)

    Fu, Qing; Zheng, Binghui; Zhao, Xingru; Wang, Lijing; Liu, Changming

    2012-01-01

    The characteristics of ammonia in drinking water sources in China were evaluated during 2005-2009. The spatial distribution and seasonal changes of ammonia in different types of drinking water sources of 22 provinces, 5 autonomous regions and 4 municipalities were investigated. The levels of ammonia in drinking water sources follow the order of river > lake/reservoir > groundwater. The levels of ammonia concentration in river sources gradually decreased from 2005 to 2008, while no obvious change was observed in the lakes/reservoirs and groundwater drinking water sources. The proportion of the type of drinking water sources is different in different regions. In river drinking water sources, the ammonia level was varied in different regions and changed seasonally. The highest value and wide range of annual ammonia was found in South East region, while the lowest value was found in Southwest region. In lake/reservoir drinking water sources, the ammonia levels were not varied obviously in different regions. In underground drinking water sources, the ammonia levels were varied obviously in different regions due to the geological permeability and the natural features of regions. In the drinking water sources with higher ammonia levels, there are enterprises and wastewater drainages in the protected areas of the drinking water sources.

  11. Ammonia - Did it have a role in chemical evolution. [abiogenesis

    Science.gov (United States)

    Ferris, J. P.; Nicodem, D. E.

    1974-01-01

    The significance of ammonia in the chemical evolution related to the origin of life is evaluated. A computer program was employed to calculate the time needed for the decomposition of ammonia by means of a photochemical reaction. Various possible protection mechanisms for ammonia are discussed, giving attention to hydrogen sulfide, hydrogen, ozone, and CO. It is concluded that in the absence of a sufficiently high pressure of hydrogen, any ammonia present in the primitive atmosphere would have been decomposed by photolysis in a million years.

  12. Compact neutron flux monitor

    International Nuclear Information System (INIS)

    Madhavi, V.; Phatak, P.R.; Bahadur, C.; Bayala, A.K.; Jakati, R.K.; Sathian, V.

    2003-01-01

    Full text: A compact size neutron flux monitor has been developed incorporating standard boards developed for smart radiation monitors. The sensitivity of the monitors is 0.4cps/nV. It has been tested up to 2075 nV flux with standard neutron sources. It shows convincing results even in high flux areas like 6m away from the accelerator in RMC (Parel) for 106/107 nV. These monitors have a focal and remote display, alarm function with potential free contacts for centralized control and additional provision of connectivity via RS485/Ethernet. This paper describes the construction, working and results of the above flux monitor

  13. Production of activated carbon by using pyrolysis process in an ammonia atmosphere

    Science.gov (United States)

    Indayaningsih, N.; Destyorini, F.; Purawiardi, R. I.; Insiyanda, D. R.; Widodo, H.

    2017-04-01

    Activated carbon is materials that have wide applications, including supercapacitor materials, absorbent in chemical industry, and absorbent material in the chemical industry. This study has carried out for the manufacturing of activated carbon from inexpensive materials through efficient processes. Carbon material was made from coconut fibers through pyrolysis process at temperature of 650, 700, 750 and 800°C. Aim of this study was to obtain carbon material that has a large surface area. Pyrolysis process is carried out in an inert atmosphere (N2 gas) at a temperature of 450°C for 30 minutes, followed by pyrolysis process in an ammonia atmosphere at 800°C for 2 hours. The pyrolysis results showed that the etching process in ammonia is occurred; as it obtained some greater surface area when compared with the pyrolisis process in an atmosphere by inert gas only. The resulted activated carbon also showed to have good properties in surface area and total pore volume.

  14. Flexible, all-organic ammonia sensor based on dodecylbenzene sulfonic acid-doped polyaniline films

    Energy Technology Data Exchange (ETDEWEB)

    Rizzo, G. [Dipartimento di Chimica Industriale e Ingegneria dei Materiali, Universita degli Studi di Messina (Italy); Arena, A.; Donato, N.; Latino, M.; Saitta, G. [Dipartimento di Fisica della Materia e Ingegneria Elettronica, Universita degli Studi di Messina (Italy); Bonavita, A. [Dipartimento di Chimica Industriale e Ingegneria dei Materiali, Universita degli Studi di Messina (Italy); Neri, G., E-mail: neri@ingegneria.unime.i [Dipartimento di Chimica Industriale e Ingegneria dei Materiali, Universita degli Studi di Messina (Italy)

    2010-09-30

    A stable chlorobenzene dispersion of conducting polyaniline (PANI) has been obtained by doping emeraldine base with dodecylbenzene sulfonic acid (DBSA) and studied by spectrophotometric measurements in the UV-vis-IR range. The electrical properties of PANI: DBSA films obtained from the above dispersion have been investigated under different temperature and relative humidity conditions. All-organic chemoresistive devices have been developed by spin-coating the PANI: DBSA dispersion on flexible substrates, and then by depositing electrodes on the top, from a carbon nanotube conducting ink. Sensing tests performed under exposition to calibrated amounts of ammonia reveal that these simple and inexpensive sensors are able to detect ammonia at room temperature in a reliable way, with a sensitivity linearly related to concentration in the range between 5 ppm and 70 ppm.

  15. Ammonia-induced robust photocatalytic hydrogen evolution of graphitic carbon nitride

    Science.gov (United States)

    Yang, Pengju; Zhao, Jianghong; Qiao, Wei; Li, Li; Zhu, Zhenping

    2015-11-01

    We report a new and effective method to prepare high activity graphitic carbon nitride (g-C3N4) by a simple ammonia etching treatment. The obtained g-C3N4 displays a high BET surface area and enhanced electron/hole separation efficiency. The hydrogen evolution rates improved from 52 μmol h-1 to 316.7 μmol h-1 under visible light.We report a new and effective method to prepare high activity graphitic carbon nitride (g-C3N4) by a simple ammonia etching treatment. The obtained g-C3N4 displays a high BET surface area and enhanced electron/hole separation efficiency. The hydrogen evolution rates improved from 52 μmol h-1 to 316.7 μmol h-1 under visible light. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr05570a

  16. Ammonia-dimethylchloramine system: kinetic approach in an aqueous medium and comparison with the mechanism involving in liquid ammonia

    OpenAIRE

    Stephan, Juliette; Pasquet, Véronique; Elkhatib, Mazen; Goutelle, Véronique; Delalu, Henri

    2008-01-01

    International audience; After an exhaustive study of the system ammonia-dimethylchloramine in liquid ammonia, it was interesting to compare the reactivity of this system in liquid ammonia with the same systeme in an aqueous medium. Dimethylchloramine prepared in a pure state, undergoes dehydrohalogenation in an alkaline medium: the principal products formed are N-methylmethanimine, 1,3,5-trimethylhexahydrotriazine, formaldehyde and methylamine. The kinetics of this reaction was studied by UV,...

  17. [Ammonia oxidation kinetics of ammonia oxidizer mixed culture under the conditions of O2 and trace NO2 mixed gasses].

    Science.gov (United States)

    Zhang, Dai-Jun; Zu, Bo; Ren, Hong-Yang; Zhang, Ping; Cong, Li-Ying; Yan, Qing

    2008-01-01

    The kinetics of the NO2-dependent ammonia oxidation was developed for ammonia oxidizer mixed culture when there was no molecular oxygen in the batch tests. The kinetics parameters were determined, where the half saturate coefficient of NO2 was 0.821 micromol x L(-1), inhibition coefficient of NO2 concentration was 1.721 micromol x L(-1), and the maximum ammonia oxidation rate were 0.144 mg x (mg x h)(-1). After adding the volume fraction of O2 was 2% to trace NO2, the ammonia oxidation rates increased obviously. The maximum ammonia oxidation rate, 0.198 mg x (mg x h)(-1) occurred under the condition of the mixed gasses containing the volume fraction of O2 was 2% and 50 x 10(-6) NO2. Under the condition of mixed gasses containing the volume fraction of O2 was 21% to trace NO2, the ammonia oxidation rates further increased greatly. The maximum ammonia oxidation rate, 0.477 mg x (mg x h)(-1) occurred when the volume fraction of O2 was 21% and 100 x 10(-6) NO2 in the mixed gas, which is 3 times higher than the general aerobic ammonia oxidation rate. The function for NO2 apparently to enhance ammonia oxidation was suggested. The kinetics model of ammonia oxidation under the conditions of O2 and trace NO2 mixed gasses was developed. The model was validated by the results of ammonia oxidation experiments under the conditions of the mixed gasses containing 2% O2 and trace NO2. The mechanism for NO2 to enhance ammonia oxidation under the conditions of O2 and trace NO2 mixed gasses was discussed.

  18. AMMONIA-FREE NOx CONTROL SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Song Wu; Zhen Fan; Andrew H. Seltzer; Richard G. Herman

    2006-06-01

    This report describes a novel NOx control system that has the potential to drastically reduce cost, and enhance performance, operation and safety of power plant NOx control. The new system optimizes the burner and the furnace to achieve very low NOx levels and to provide an adequate amount of CO, and uses the CO for reducing NO both in-furnace and over a downstream AFSCR (ammonia-free selective catalytic reduction) reactor. The AF-SCR combines the advantages of the highly successful SCR technology for power plants and the TWC (three-way catalytic converter) widely used on automobiles. Like the SCR, it works in oxidizing environment of combustion flue gas and uses only base metal catalysts. Like the TWC, the AF-SCR removes NO and excess CO simultaneously without using any external reagent, such as ammonia. This new process has been studied in a development program jointed funded by the US Department of Energy and Foster Wheeler. The report outlines the experimental catalyst work performed on a bench-scale reactor, including test procedure, operating conditions, and results of various catalyst formulations. Several candidate catalysts, prepared with readily available transition metal oxides and common substrate materials, have shown over 80-90% removal for both NO and CO in oxidizing gas mixtures and at elevated temperatures. A detailed combustion study of a 400 MWe coal-fired boiler, applying computational fluid dynamics techniques to model boiler and burner design, has been carried out to investigate ways to optimize the combustion process for the lowest NOx formation and optimum CO/NO ratios. Results of this boiler and burner optimization work are reported. The paper further discusses catalyst scale-up considerations and the conceptual design of a 400 MWe size AF-SCR reactor, as well as economics analysis indicating large cost savings of the ammonia-free NOx control process over the current SCR technology.

  19. Exposure of lambs to atmospheric ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Drummond, J.G.; Curtis, S.E.; Lewis, J.M.; Hinds, F.C.; Simon, J.

    1976-01-01

    Two trials were conducted to determine the effects of chronic exposure to atmospheric ammonia at a concentration of 75 ppm on weight gain and efficiency of feed conversion by lambs. Lambs were weighed and then randomly allotted to four dynamic air-pollutant exposure chambers. Initial weights (mean +/- SE) of lambs were 22.1 +/- .46 kg and 27.5 +/- 1.54 kg for trials 1 and 2, respectively (n=12 in both trials). Lambs in two chambers (controls) were maintained in an atmosphere of filtered room air. Lambs in the other two chambers (NH/sub 3/ -exposed) were exposed to an atmosphere of filtered air plus atmospheric ammonia at a concentration of 75 ppm. Exposure period was 28 days in both trials. Feed and water were available at all times. Lamb weight gain and feed disappearance were determined weekly. Upon termination of each trial, one lamb was randomly selected from each chamber, sacrificed, and gross and histopathologic structural changes noted. Weight gain and efficiency of feed conversion data for the two trials were combined for statistical analysis. Control lambs gained on the average .09 kg/day (.28 vs .19) more (P<.01) and consumed on the average .68 kg of feed (4.53 vs 5.21) less per kilogram of weight gain (P<.10) than did NH/sub 3/-exposed lambs. Ammonia-exposed lambs in both trials showed profuse lacrimation, severe coughing and sneezing, and profuse nasal discharge, which was bloody in some instances. Gross and histopathologic findings appeared to be qualitatively similar between treatments, but more pronounced in NH/sub 3/-exposed lambs.

  20. TES ammonia retrieval strategy and global observations of the spatial and seasonal variability of ammonia (journal)

    Science.gov (United States)

    Presently only limited sets of tropospheric ammonia (NH3) measurements in the Earth's atmosphere have been reported from satellite and surface station measurements, despite the well-documented negative impact of NH3 on the environment and human health. Presented here is a detaile...

  1. Video Meteor Fluxes

    Science.gov (United States)

    Campbell-Brown, M. D.; Braid, D.

    2011-01-01

    The flux of meteoroids, or number of meteoroids per unit area per unit time, is critical for calibrating models of meteoroid stream formation and for estimating the hazard to spacecraft from shower and sporadic meteors. Although observations of meteors in the millimetre to centimetre size range are common, flux measurements (particularly for sporadic meteors, which make up the majority of meteoroid flux) are less so. It is necessary to know the collecting area and collection time for a given set of observations, and to correct for observing biases and the sensitivity of the system. Previous measurements of sporadic fluxes are summarized in Figure 1; the values are given as a total number of meteoroids striking the earth in one year to a given limiting mass. The Gr n et al. (1985) flux model is included in the figure for reference. Fluxes for sporadic meteoroids impacting the Earth have been calculated for objects in the centimeter size range using Super-Schmidt observations (Hawkins & Upton, 1958); this study used about 300 meteors, and used only the physical area of overlap of the cameras at 90 km to calculate the flux, corrected for angular speed of meteors, since a large angular speed reduces the maximum brightness of the meteor on the film, and radiant elevation, which takes into account the geometric reduction in flux when the meteors are not perpendicular to the horizontal. They bring up corrections for both partial trails (which tends to increase the collecting area) and incomplete overlap at heights other than 90 km (which tends to decrease it) as effects that will affect the flux, but estimated that the two effects cancelled one another. Halliday et al. (1984) calculated the flux of meteorite-dropping fireballs with fragment masses greater than 50 g, over the physical area of sky accessible to the MORP fireball cameras, counting only observations in clear weather. In the micron size range, LDEF measurements of small craters on spacecraft have been used to

  2. Ammonia-Free NOx Control System

    Energy Technology Data Exchange (ETDEWEB)

    Song Wu; Zhen Fan; Andrew H. Seltzer; Richard G. Herman

    2005-03-31

    Research is being conducted under United States Department of Energy (DOE) Contract DE-FC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia.

  3. Ammonia-Free NOx Control System

    Energy Technology Data Exchange (ETDEWEB)

    Song Wu; Zhen Fan; Andrew H. Seltzer

    2005-06-30

    Research is being conducted under United States Department of Energy (DOE) Contract DEFC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia.

  4. Nonadiabatic transitions in electrostatically trapped ammonia molecules

    International Nuclear Information System (INIS)

    Kirste, Moritz; Schnell, Melanie; Meijer, Gerard; Sartakov, Boris G.

    2009-01-01

    Nonadiabatic transitions are known to be major loss channels for atoms in magnetic traps but have thus far not been experimentally reported upon for trapped molecules. We have observed and quantified losses due to nonadiabatic transitions for three isotopologues of ammonia in electrostatic traps by comparing the trapping times in traps with a zero and a nonzero electric field at the center. Nonadiabatic transitions are seen to dominate the overall loss rate even for the present samples that are at relatively high temperatures of 30 mK. It is anticipated that losses due to nonadiabatic transitions in electric fields are omnipresent in ongoing experiments on cold molecules.

  5. Modeling and simulation of ammonia removal from purge gases of ammonia plants using a catalytic Pd-Ag membrane reactor

    International Nuclear Information System (INIS)

    Rahimpour, M.R.; Asgari, A.

    2008-01-01

    In this work, the removal of ammonia from synthesis purge gas of an ammonia plant has been investigated. Since the ammonia decomposition is thermodynamically limited, a membrane reactor is used for complete decomposition. A double pipe catalytic membrane reactor is used to remove ammonia from purge gas. The purge gas is flowing in the reaction side and is converted to hydrogen and nitrogen over nickel-alumina catalyst. The hydrogen is transferred through the Pd-Ag membrane of tube side to the shell side. A mathematical model including conservation of mass in the tube and shell side of reactor is proposed. The proposed model was solved numerically and the effects of different parameters on the rector performance were investigated. The effects of pressure, temperature, flow rate (sweep ratio), membrane thickness and reactor diameter have been investigated in the present study. Increasing ammonia conversion was observed by raising the temperature, sweep ratio and reducing membrane thickness. When the pressure increases, the decomposition is gone toward completion but, at low pressure the ammonia conversion in the outset of reactor is higher than other pressures, but complete destruction of the ammonia cannot be achieved. The proposed model can be used for design of an industrial catalytic membrane reactor for removal of ammonia from ammonia plant and reducing NO x emissions

  6. Eddy Correlation Flux Measurement System (ECOR) Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Cook, DR

    2011-01-31

    The eddy correlation (ECOR) flux measurement system provides in situ, half-hour measurements of the surface turbulent fluxes of momentum, sensible heat, latent heat, and carbon dioxide (CO2) (and methane at one Southern Great Plains extended facility (SGP EF) and the North Slope of Alaska Central Facility (NSA CF). The fluxes are obtained with the eddy covariance technique, which involves correlation of the vertical wind component with the horizontal wind component, the air temperature, the water vapor density, and the CO2 concentration.

  7. Magnetic refrigeration using flux compression in superconductors

    International Nuclear Information System (INIS)

    Israelsson, U.E.; Strayer, D.M.; Jackson, H.W.; Petrac, D.

    1990-01-01

    The feasibility of using flux compression in high-temperature superconductors to produce the large time-varying magnetic fields required in a field cycled magnetic refrigerator operating between 20 K and 4 K is presently investigated. This paper describes the refrigerator concept and lists limitations and advantages in comparison with conventional refrigeration techniques. The maximum fields obtainable by flux compression in high-temperature superconductor materials, as presently prepared, are too low to serve in such a refrigerator. However, reports exist of critical current values that are near usable levels for flux pumps in refrigerator applications. 9 refs

  8. Reaction between carbonyl compound and ammonia on the bimetallic catalyst the Eu, Yb system; Eu, Yb kei baimetarikku shokubaijo deno karuboniru kagobutsu to anmonia tono hanno

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-09-01

    Ln-Cu/Al{sub 2}O{sub 3}, Ln-Fe/SiO{sub 2}, Ln-Ni/SiO{sub 2}, Ln-Co/SiO{sub 2} bimetallic catalyst are obtained Cu/Al{sub 2}O{sub 3}, Fe/SiO{sub 2} and Ni/SiO{sub 2} and Co/SiO{sub 2}, when it reacted with the rare metal which dissolved in the liquid ammonia. Using it, the reaction between carbonyl compound and ammonia was examined at 473-523K reaction temperature. In the reaction between carbonyl compound and ammonia, these bimetallic catalysts can be developed to amination and reductive alkylation, those relation reactions and in order to show the activity for hydrogenation, dehydrogenation and conversion hydrogenation, which made the ammonia to be the hydrogen source. The catalysis greatly changed with the rare earth metal composition in the catalyst. Especially, the Ln-Cu/Al{sub 2}O{sub 3} catalyst showed the activity for the reaction between methyl acetate and ammonia. By adding the rare earth metal at Cu/Al{sub 2}O{sub 3}, the Eu-Cu/Al{sub 2}O{sub 3} catalyst was more activated, and the acetonitrile was given. Eu-Cu /Al{sub 2}O{sub 3}, since it has the high activity for the conversion hydrogenation from the ammonia, the reductive amination progressed acetone ammonia hydrogen, and isopropylamine was formed. (translated by NEDO)

  9. Steel corrosion in ammonia solutions studied by Moessbauer spectrometry

    International Nuclear Information System (INIS)

    Bibicu, I.; Samide, A.; Preda, M.

    2002-01-01

    The corrosive action of diluted ammonia solutions has been thoroughly studied until 90s. A particular interest towards studying it after this time arisen from problems relating to environment protection. We have initiated a programme which involves the study of steel samples in ammoniac solutions. The steel samples were obtained from industrial Fe-C steel with C of low concentration. The surface of the samples was diamond polished, subsequently degreased and desiccated. The corrosion process of the samples was performed in an electrolytic cell with diluted ammonia solutions of concentration ranging within 10 -1 - 10 -4 N. Moessbauer measurements were performed at room temperature in the transmission (TMS) and conversion electron spectroscopy (CEMS) using a conventional constant-acceleration spectrometer with a 57 Co-Rh source. The TMS spectrum shows the presence of a single sextet: α-iron. The best fit of the CEMS spectra uses an addition wide line to the sextet. The parameters of the wide line correspond to a non-stoichiometric oxide with (probably) small particles. Also the line parameters prove that we have studied the early stage of the corrosion process. All CEMS spectra show that on the surface the directions of the γ-ray and the magnetic moments are nearly perpendicular. There is a magnetic anisotropy on the surface of the samples, which remains even in the corroded samples. In contrast TMS spectrum shows that in the interior of the sample the magnetic moments are in a random arrangement. The result of the corrosion is the layer appearance (non-stoichiometric iron oxide) on the sample surface. The layer thickness increases with the change of the NH 3 concentration from 10 -1 to 10 -4 N. (authors)

  10. Kinetics of Chlorination of Benzophenone-3 in the Presence of Bromide and Ammonia.

    Science.gov (United States)

    Abdallah, Pamela; Deborde, Marie; Dossier Berne, Florence; Karpel Vel Leitner, Nathalie

    2015-12-15

    The aim of this study was to assess the impact of chlorination on the degradation of one of the most commonly used UV filters (benzophenone-3 (BP-3)) and the effects of bromide and ammonia on the kinetics of BP-3 elimination. Bromide and ammonia are rapidly converted to bromine and chloramines during chlorination. At first, the rate constants of chlorine, bromine and monochloramine with BP-3 were determined at various pH levels. BP-3 was found to react rapidly with chlorine and bromine, with values of apparent second order rate constants equal to 1.25(±0.14) × 10(3) M(-1)·s(-1) and 4.04(±0.54) × 10(6) M(-1)·s(-1) at pH 8.5 for kChlorine/BP-3 and kBromine/BP-3, respectively, whereas low monochloramine reactivity was observed (kNH2Cl/BP-3 = 0.112 M(-1)·s(-1)). To assess the impact of the inorganic content of water on BP-3 degradation, chlorination experiments with different added concentrations of bromide and/or ammonia were conducted. Under these conditions, BP-3 degradation was found to be enhanced in the presence of bromide due to the formation of bromine, whereas it was inhibited in the presence of ammonia. However, the results obtained were pH dependent. Finally, a kinetic model considering 18 reactions was developed using Copasi to estimate BP-3 degradation during chlorination in the presence of bromide and ammonia.

  11. Nitrogen potential recovery and concentration of ammonia from swine manure using electrodialysis coupled with air stripping.

    Science.gov (United States)

    Ippersiel, D; Mondor, M; Lamarche, F; Tremblay, F; Dubreuil, J; Masse, L

    2012-03-01

    The practice of intensive animal production in certain areas has resulted in excessive manure production for the available regional land base. Consequently, there is a need to develop treatment technologies to recover the valuable nutrients that manure contains so that the resulting product can be transported and used as fertilizer on agricultural land. The project presented here used electrodialysis in a dilution/concentration configuration to transfer the manure ammonia in the diluate solution by electromigration to an adjacent solution separated by an ion-exchange membrane under the driving force of an electrical potential. Then, air stripping from the electrodialysis-obtained concentrate solution without pH modification was used to isolate the ammonia in an acidic solution. An optimal process operating voltage of 17.5 V was first determined on the basis of current efficiency and total energy consumption. During the process, the swine manure pH varied from 8.5 to 8.2, values favourable for NH(4)(+) electromigration. Total ammonia nitrogen reached 21,352 mg/L in the concentrate solution, representing approximately seven times the concentration in the swine manure. Further increases in concentration were limited by water transfer from the diluate solution due to electroosmosis and osmosis. Applying vacuum to the concentrate reservoir was found to be more efficient than direct concentrate solution aeration for NH(3) recuperation in the acid trap, given that the ammonia recuperated under vacuum represented 14.5% of the theoretical value of the NH(3) present in the concentrate solution as compared to 6.2% for aeration. However, an excessively low concentrate solution pH (8.6-8.3) limited NH(3)volatilization toward the acid trap. These results suggest that the concentrate solution pH needs to be raised to promote the volatile NH(3) form of total ammonia nitrogen. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

  12. Improving The Efficiency Of Ammonia Electrolysis For Hydrogen Production

    Science.gov (United States)

    Palaniappan, Ramasamy

    Given the abundance of ammonia in domestic and industrial wastes, ammonia electrolysis is a promising technology for remediation and distributed power generation in a clean and safe manner. Efficiency has been identified as one of the key issues that require improvement in order for the technology to enter the market phase. Therefore, this research was performed with the aim of improving the efficiency of hydrogen production by finding alternative materials for the cathode and electrolyte. 1. In the presence of ammonia the activity for hydrogen evolution reaction (HER) followed the trend Rh>Pt>Ru>Ni. The addition of ammonia resulted in lower rates for HER for Pt, Ru, and Ni, which have been attributed to competition from the ammonia adsorption reaction. 2. The addition of ammonia offers insight into the role of metal-hydrogen underpotential deposition (M-Hupd) on HER kinetics. In addition to offering competition via ammonia adsorption it resulted in fewer and weaker M-Hupd bonds for all metals. This finding substantiates the theory that M-Hupd bonds favor HER on Pt electrocatalyst. However, for Rh results suggest that M-Hupd bond may hinder the HER. In addition, the presence of unpaired valence shell electrons is suggested to provide higher activity for HER in the presence of ammonia. 3. Bimetals PtxM1-x (M = Ir, Ru, Rh, and Ni) offered lower overpotentials for HER compared to the unalloyed metals in the presence of ammonia. The activity of HER in the presence of ammonia follows the trend Pt-Ir>Pt-Rh>Pt-Ru>Pt-Ni. The higher activity of HER is attributed to the synergistic effect of the alloy, where ammonia adsorbs onto the more electropositive alloying metal leaving Pt available for Hupd formation and HER to take place. Additionally, this supports the theory that the presence of a higher number of unpaired electrons favors the HER in the presence of ammonia. 4. Potassium polyacrylate (PAA-K) was successfully used as a substitute for aqueous KOH for ammonia

  13. Staging properties of potassium-ammonia ternary graphite intercalation compounds at high ammonia pressure

    Science.gov (United States)

    Qian, X. W.; Solin, S. A.

    1989-04-01

    The pressure dependence of the (00l) x-ray diffraction patterns of the ternary graphite intercalation compound K(NH3)xC24 has been studied in the range 0.5-11 kbar (for which x~4.5) using a diamond anvil cell. A special apparatus for loading the cell with liquid ammonia at room temperature has been constructed and is briefly described. In these experiments, the pressure-transmitting fluid was also an intercalant, namely ammonia. Therefore, the chemical potential of this species was linearly coupled to the applied pressure in contrast to the usual case where the pressure-transmitting fluid is chemically passive. The pressure dependences of the basal spacings and of the relative intensities of key reflections have been measured, as have the compressibilities of the stage-1 and stage-2 components of the two-phase system. Basal-spacing anomalies and anomalies in the relative intensities occur at pressures of ~3.5 and 8.0 kbar and are tentatively attributed to in-plane coordination changes in the potassium-ammonia ratio. Using thermodynamic arguments and Le Chatelier's principle we show quantitatively that a staging phase transition from pure stage-1 phase to an admixture of stage-1 and stage-2 is expected with increased pressure above 10 bar in agreement with experiment. The saturation ammonia compositions (x values) of the admixed stages are found to be 4.5 and 5.4 for the stage-1 and -2 components, respectively. This result is interpreted as evidence that the composition is not sterically limited but is determined by the binding energy of ammonia for potassium and by the perturbation to this energy from the guest-host interaction.

  14. Solar Magnetic Flux Ropes

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... The most probable initial magnetic configuration of a CME is a flux rope consisting of twisted field lines which fill the whole volume of a dark coronal cavity. The flux ropes can be in stable equilibrium in the coronal magnetic field for weeks and even months, but suddenly they lose their stability and erupt with ...

  15. Growth of N-polar GaN by ammonia molecular beam epitaxy

    Science.gov (United States)

    Fireman, M. N.; Li, Haoran; Keller, Stacia; Mishra, Umesh K.; Speck, James S.

    2018-01-01

    The homoepitaxial growth of N-polar GaN was investigated by ammonia molecular beam epitaxy. Systematic growth studies varying the V/III flux ratio and the growth temperature indicated that the strongest factor in realizing morphologically smooth films was the growth temperature; N-face films needed to be grown approximately 100 °C or greater than Ga-face films provided the same metal flux. Smooth N-face films could also be grown at temperatures only 50 °C greater than Ga-face films, albeit under reduced metal flux. Too high a growth temperature and too low a metal flux resulted in dislocation mediated pitting of the surface. The unintentional impurity incorporation of such films was also studied by secondary mass ion spectroscopy and most importantly revealed an oxygen content in the mid 1017 to the mid 1018 cm-3 range. Hall measurements confirmed that this oxygen impurity resulted in n-type films, with carrier concentrations and mobilities comparable to those of intentionally silicon doped GaN.

  16. PRETREATMENT AND FRACTIONATION OF CORN STOVER BY AMMONIA RECYCLE PERCOLATION PROCESS. (R831645)

    Science.gov (United States)

    Corn stover was pretreated with aqueous ammonia in a flow-through column reactor,a process termed as Ammonia Recycle Percolation (ARP). The aqueous ammonia causesswelling and efficient delignification of biomass at high temperatures. The ARPprocess solubilizes abou...

  17. Thermodynamic analysis and optimization of an ammonia-water power system with LNG (liquefied natural gas) as its heat sink

    International Nuclear Information System (INIS)

    Wang, Jiangfeng; Yan, Zhequan; Wang, Man; Dai, Yiping

    2013-01-01

    Due to a good behavior of ammonia-water during the two-phase heat addition process and the liquefied natural gas with great cold energy, an ammonia-water power system with LNG as its heat sink is proposed to utilize the low grade waste heat. Based on the thermodynamic mathematical models, the effects of key thermodynamic design parameters, including turbine inlet pressure, turbine inlet temperature, ammonia mass fraction, pinch temperature difference and approach temperature difference in the heat recovery vapor generator, on the system performance are examined from the view of both thermodynamics and economics. To obtain the optimum performance, multi-objective optimization is conducted to find the best thermodynamic design parameters from both thermodynamic and economic aspects using NSGA-II (Non-dominated sorting genetic algorithm-II). The exergy efficiency, total heat transfer capability and turbine size parameter are selected as three objective functions to maximize the exergy efficiency, and minimize the total heat transfer capability and turbine size parameter under the given waste heat conditions. The results show that turbine inlet pressure, turbine inlet temperature, ammonia mass fraction, pinch temperature difference and approach temperature difference have significant effects on the system performance. By multi-objective optimization, the Pareto frontier solution for the ammonia-water power system is obtained. - Highlights: ► An ammonia-water power system with LNG as its heat sink is proposed. ► The effects of key parameters on the system performance are examined. ► Multi-objective optimization is conducted to obtain optimum system performance

  18. Flavour mixings in flux compactifications

    International Nuclear Information System (INIS)

    Buchmuller, Wilfried; Schweizer, Julian

    2017-01-01

    A multiplicity of quark-lepton families can naturally arise as zero-modes in flux compactifications. The flavour structure of quark and lepton mass matrices is then determined by the wave function profiles of the zero-modes. We consider a supersymmetric SO(10) x U(1) model in six dimensions compactified on the orbifold T 2 =Z 2 with Abelian magnetic flux. A bulk 16-plet charged under the U(1) provides the quark-lepton generations whereas two uncharged 10-plets yield two Higgs doublets. Bulk anomaly cancellation requires the presence of additional 16- and 10-plets. The corresponding zero-modes form vectorlike split multiplets that are needed to obtain a successful flavour phenomenology. We analyze the pattern of flavour mixings for the two heaviest families of the Standard Model and discuss possible generalizations to three and more generations.

  19. Atmospheric cycles of nitrogen oxides and ammonia

    International Nuclear Information System (INIS)

    Bottger, A.; Ehhalt, D.H.; Gravenhorst, G.

    1981-12-01

    The atmospheric cycles of nitrogenous trace compounds for the Northern and Southern Hemispheres are discussed. Source strengths and destruction rates for the nitrogen oxides: NO, NO 2 and HNO 3 -(NOx) and ammonia (NH 3 ) are given as a function of latitude over continents and oceans. The global amounts of NOx-N and NH 3 -N produced annually in the period 1950 to 1975 (34 + 5 x one trillion g NOx-N/yr and 29 + or - 6 x one trillion g NH3-N/yr) are much less than previously assumed. Globally, natural and anthropogenic emissions are of similar magnitude. The NOx emission from anthropogenic sources is 1.5 times that from natural processes in the Northern Hemisphere, whereas in the Southern Hemisphere, it is a factor of 3 or 4 less. More than 80% of atmospheric ammonia seems to be derived from excrements of domestic animals, mostly by bulk deposition: 24 + or - 9 x one trillion g NO 3 -N/yr and 21 + or - 9 x one trillion g NH 4 +-N/yr. Another fraction may be removed by absorption on vegetation and soils

  20. Method of production of ammonia synthesis gas

    Energy Technology Data Exchange (ETDEWEB)

    1943-09-10

    In the catalytic synthesis of complicated hydrocarbons from carbon monoxide and hydrogen at normal or slightly increased pressures by the Fischer--Tropsch process, or carried out at higher pressures in some other proposals, the synthesis gas was incompletely transformed. After the conclusion of the synthesis, the residual gas, upon the separation of the liquid constituents, contained, in addition to the unreacted carbon moxoxide and hydrogen, also considerable amounts of methane, carbon dioxide, and nitrogen from the original synthesis gas. This residual gas had been used as fuel. It was, however, pure and contained no sulfur or other catalyst poisons and burning it was considered uneconomical. It was proposed to make better use of it by using it as fuel. It was, however, pure and contained no sulfur or other catalyst poisons and burning it was considered uneconomical. It was proposed to make better use of it by using it as a raw material for the production of synthesis gas by decomposing the methane present in it with steam according to the equation CH/sub 4/ + H/sub 2/O = CO + 3H/sub 2/. This conversion was to be brought about either by a return to the producers or else in special splitting units. Also, it had been found that the residual gas, possibly even in the presence of oxygen compounds, could be conveniently used for the synthesis of ammonia. Several examples of ammonia synthesis were discussed.

  1. Study of ammonia synthesis using technetium catalysts

    International Nuclear Information System (INIS)

    Spitsyn, V.I.; Mikhajlenko, I.E.; Pokrovskaya, O.V.

    1982-01-01

    A study was made on catalytic properties of technetium in ammonia synthesis reaction. The preparation of technetium catalysts on ν-Al 2 O 3 , BaTiO 3 , BaO-ν-Al 2 O 3 substrates is described. The investigation of catalytic activity of catalysts was carried out at a pressure of 1 atm. in vertical reactor with volume rate of 15000 h - 1 in the temperature range of 350-425 deg. The amount of catalyst was 0.5-1 g, the volume- 0.5 ml, the size of granules- 2-3 mm. Rate constants of ammonia synthesis reaction were calculated. Seeming activation energies of the process have meanings wihtin the limits of 40-50 kcal/mol. It was shown that with increase in concentration of Tc on BaTiO 3 the catalytic activity rises in comparison with pure Tc. The reduction of catalytic activity with increase of metal content on Al 2 O 3 begins in the limits of 3.5-6.7% Tc/ν-Al 2 O 3 . The catalyst of 5.3% Tc/4.1% Ba/ν -Al 2 O 3 compound has the maximum activity. Technetium catalysts possess the stable catalytic activity and don't requre its reduction during several months

  2. Ammonia-Oxidizing Archaea and Bacteria Differentially Contribute to Ammonia Oxidation in Sediments from Adjacent Waters of Rushan Bay, China

    Directory of Open Access Journals (Sweden)

    Hui He

    2018-02-01

    Full Text Available Ammonia oxidation plays a significant role in the nitrogen cycle in marine sediments. Ammonia-oxidizing archaea (AOA and bacteria (AOB are the key contributors to ammonia oxidation, and their relative contribution to this process is one of the most important issues related to the nitrogen cycle in the ocean. In this study, the differential contributions of AOA and AOB to ammonia oxidation in surface sediments from adjacent waters of Rushan Bay were studied based on the ammonia monooxygenase (amoA gene. Molecular biology techniques were used to analyze ammonia oxidizers’ community characteristics, and potential nitrification incubation was applied to understand the ammonia oxidizers’ community activity. The objective was to determine the community structure and activity of AOA and AOB in surface sediments from adjacent waters of Rushan Bay and to discuss the different contributions of AOA and AOB to ammonia oxidation during summer and winter seasons in the studied area. Pyrosequencing analysis revealed that the diversity of AOA was higher than that of AOB. The majority of AOA and AOB clustered into Nitrosopumilus and Nitrosospira, respectively, indicating that the Nitrosopumilus group and Nitrosospira groups may be more adaptable in studied sediments. The AOA community was closely correlated to temperature, salinity and ammonium concentration, whereas the AOB community showed a stronger correlation with temperature, chlorophyll-a content (chla and nitrite concentration. qPCR results showed that both the abundance and the transcript abundance of AOA was consistently greater than that of AOB. AOA and AOB differentially contributed to ammonia oxidation in different seasons. AOB occupied the dominant position in mediating ammonia oxidation during summer, while AOA might play a dominant role in ammonia oxidation during winter.

  3. Experimental and Numerical Study on Effects of Airflow and Aqueous Ammonium Temperature on Ammonia Mass Transfer Coefficient

    DEFF Research Database (Denmark)

    Rong, Li; Nielsen, Peter V.; Zhang, Guoqiang

    2010-01-01

    transfer are investigated by using computational fluid dynamics (CFD) modeling and by a mechanism modeling using dissociation constant and Henry's constant models based on the parameters measured in the experiments performed in a wind tunnel. The validated CFD model by experimental data is used......This paper reports the results of an investigation, based on fundamental fluid dynamics and mass transfer theory, carried out to obtain a general understanding of ammonia mass transfer from an emission surface. The effects of airflow and aqueous ammonium solution temperature on ammonia mass...

  4. An infrared spectroscopy method to detect ammonia in gastric juice.

    Science.gov (United States)

    Giovannozzi, Andrea M; Pennecchi, Francesca; Muller, Paul; Balma Tivola, Paolo; Roncari, Silvia; Rossi, Andrea M

    2015-11-01

    Ammonia in gastric juice is considered a potential biomarker for Helicobacter pylori infection and as a factor contributing to gastric mucosal injury. High ammonia concentrations are also found in patients with chronic renal failure, peptic ulcer disease, and chronic gastritis. Rapid and specific methods for ammonia detection are urgently required by the medical community. Here we present a method to detect ammonia directly in gastric juice based on Fourier transform infrared spectroscopy. The ammonia dissolved in biological liquid samples as ammonium ion was released in air as a gas by the shifting of the pH equilibrium of the ammonium/ammonia reaction and was detected in line by a Fourier transform infrared spectroscopy system equipped with a gas cell for the quantification. The method developed provided high sensitivity and selectivity in ammonia detection both in pure standard solutions and in a simulated gastric juice matrix over the range of diagnostic concentrations tested. Preliminary analyses were also performed on real gastric juice samples from patients with gastric mucosal injury and with symptoms of H. pylori infection, and the results were in agreement with the clinicopathology information. The whole analysis, performed in less than 10 min, can be directly applied on the sample without extraction procedures and it ensures high specificity of detection because of the ammonia fingerprint absorption bands in the infrared spectrum. This method could be easily used with endoscopy instrumentation to provide information in real time and would enable the endoscopist to improve and integrate gastroscopic examinations.

  5. Modelling of ammonia emissions from dairy cow houses

    NARCIS (Netherlands)

    Monteny, G.J.

    2000-01-01

    Dairy cow husbandry contributes to environmental acidification through the emission of ammonia. In-depth knowledge on the processes and variable factors that play a role in the emission of ammonia from dairy cow houses benefits the production of emission data, the development of low

  6. Niche differentiation between ammonia-oxidizing bacteria in aquatic environments

    NARCIS (Netherlands)

    Coci, M.

    2007-01-01

    The aim of the studies presented in this thesis was the search for niche differentiation between the ammonia-oxidizing bacteria in aquatic environments. Ammonia-oxidizing bacteria are chemolitho-autotrophic microorganisms responsible for the first, mostly rate-limiting step of the nitrification

  7. Electro Decomposition of Ammonia into Hydrogen for Fuel Cell Use

    Science.gov (United States)

    2012-01-01

    400 million gallon per day (MGD). Currently, wastewater treatment solutions for ammonia ( biological and chemical treatments) consume a significant...of the catalytic and inhibition mechanisms of urease. Journal of Biological Inorganic Chemistry. 6(3):300-314. National Research Council (NRC) and...electrodes for urea oxidation (Talk) Denitrification of wastewater through ammonia electrolysis (Talk) Journal publicationsg Daramola, Damilola A

  8. Ammonia loss, ammonium and nitrate accumulation from mixing ...

    African Journals Online (AJOL)

    user

    2011-04-25

    Apr 25, 2011 ... Ammonia loss from urea significantly hinders efficient use of urea in agriculture. In order to reduce ammonia loss and, at the same time, improve beneficial accumulation of soil exchangeable ammonium and nitrate for efficient utilization by plants, this laboratory study was conducted to determine the effect.

  9. Electrolytic synthesis of ammonia in molten salts under atmospheric pressure.

    Science.gov (United States)

    Murakami, Tsuyoshi; Nishikiori, Tokujiro; Nohira, Toshiyuki; Ito, Yasuhiko

    2003-01-15

    Ammonia was successfully synthesized by using a new electrochemical reaction with high current efficiency at atmospheric pressure and at lower temperatures than the Haber-Bosch process. In this method, nitride ion (N3-), which is produced by the reduction from nitrogen gas at the cathode, is anodically oxidized and reacts with hydrogen to produce ammonia at the anode.

  10. Ammonia role in WWER primary circuit water chemistry optimization

    International Nuclear Information System (INIS)

    Kritskij, V.G.; Stjagkin, P.S.; Chvedova, M.N.; Slobodov, A.A.

    1999-01-01

    Ammonia influence on iron crud's solubility at 300 deg. C and different relations of boric acid and alkaline cation sum are considered. Reduction of dose rate on WWER-440 steam generators at average ammonia concentration increasing is empirically explained. Practical recommendations on optimization of WWER primary circuit water chemistry are given. (author)

  11. AMINA-chip : a miniaturized measurement system for ambient ammonia

    NARCIS (Netherlands)

    Timmer, Björn Herman

    2004-01-01

    The development of a miniaturized and integrated measurement system for gaseous ammonia is described in this thesis. The measuring principle, ¿AMINA¿, is an indirect method for selectively measuring ammonia that makes use of pH-transitions, electrolyte conductivity detection and phaseseparating

  12. Kinetics of absorption of carbon dioxide in aqueous ammonia solutions

    NARCIS (Netherlands)

    Derks, P. W. J.; Versteeg, G. F.

    2009-01-01

    In the present work the absorption of carbon dioxide into aqueous ammonia solutions has been studied in a stirred cell reactor, at low temperatures and ammonia concentrations ranging from 0.1 to about 7 kmol m-3. The absorption experiments were carried out at conditions where the so-called pseudo

  13. Ammonia treated Mo/AC catalysts for CO hydrogenation with ...

    Indian Academy of Sciences (India)

    A series of ammonia treated Mo/Activated Carbon (AC) catalysts were synthesized by wet impregnation method by nominal incorporation of 5, 10 and 15 wt% of molybdenum. The calcined catalysts (500◦C, 4 h, N₂ flow) were subjected to a stepwise ammonia treatment at temperatures from 25 up to 700◦C. This work ...

  14. Ammonia loss, ammonium and nitrate accumulation from mixing ...

    African Journals Online (AJOL)

    Ammonia loss from urea significantly hinders efficient use of urea in agriculture. In order to reduce ammonia loss and, at the same time, improve beneficial accumulation of soil exchangeable ammonium and nitrate for efficient utilization by plants, this laboratory study was conducted to determine the effect of mixing urea with ...

  15. Consumption of ammonia-nitrogen by aob in immobilized batch ...

    African Journals Online (AJOL)

    This study investigated the performance of bio-filters immobilized nitrifying bacteria, ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB). In particular, it was to assess the consumption of ammonia-nitrogen (NH3-N) by the AOB. The experiment was conducted in a one litre reactor.The reactor consisted of ...

  16. Lignin solubilisation and gentle fractionation in liquid ammonia

    NARCIS (Netherlands)

    Strassberger, Z.; Prinsen, P.; Klis, van der F.; Es, van D.S.; Tanase, S.; Rothenberg, G.

    2015-01-01

    We present a simple method for solubilising lignin using liquid ammonia. Unlike water, which requires harsh conditions, ammonia can solubilise technical lignins, in particular kraft lignin. A commercial pine wood Kraft lignin (Indulin AT) was solubilized instantaneously at room temperature and 7–11

  17. Thermodynamic Model for the Ammonia-Water System

    DEFF Research Database (Denmark)

    Thomsen, Kaj; Rasmussen, Peter

    2000-01-01

    The ammonia-water system is described by the Extended UNIQUAC model, which is an electrolyte model, formed by combining the original UNIQUAC model, the Debye-Hückel law and the Soave-Redlich-Kwong equation of state. The model is limited to temperatures below the critical temperature of ammonia. V...

  18. Association between the blood concentrations of ammonia and carnitine/amino acid of schizophrenic patients treated with valproic acid.

    Science.gov (United States)

    Ando, Masazumi; Amayasu, Hideaki; Itai, Takahiro; Yoshida, Hisahiro

    2017-01-01

    Administration of valproic acid (VPA) is complicated with approximately 0.9% of patients developing hyperammonemia, but the pathogenesis of this adverse effect remains to be clarified. The aim of the present study was to search for mechanisms associated with VPA-induced hyperammonemia in the light of changes in serum amino acids concentrations associated with the urea cycle of schizophrenic patients. Blood samples (10 mL) were obtained from 37 schizophrenic patients receiving VPA for the prevention of violent behaviors in the morning after overnight fast. Blood concentrations of ammonia, VPA, free carnitine, acyl-carnitine, and 40 amino acids including glutamate and citrulline were measured for each patient. Univariate and multivariate regression analyses were performed to identify amino acids or concomitantly administered drugs that were associated with variability in the blood concentrations of ammonia. The blood ammonia level was positively correlated with the serum glutamate concentration ( r  = 0.44, p  blonanserin ( p  < 0.01) was positively associated with the elevation of the blood ammonia level. We hypothisized that VPA would elevate the blood ammonia level of schizophrenic patients. The observed changes in serum amino acids are compatible with urea cycle dysfunction, possibly due to reduced carbamoyl-phosphate synthase 1 (CPS1) activity. We conclude that VPA should be prudently prescribed to schizophrenic patients, particularly those receiving mood stabilizers or certain antipsychotics.

  19. Shifts in the pelagic ammonia-oxidizing microbial communities along the eutrophic estuary of Yong River in Ningbo City, China

    Directory of Open Access Journals (Sweden)

    Qiufang eZhang

    2015-10-01

    Full Text Available Aerobic ammonia oxidation plays a key role in the nitrogen cycle, and the responsible microorganisms diversities are regulated by environmental factors. Abundance and composition of ammonia-oxidizing archaea (AOA and ammonia-oxidizing bacteria (AOB were investigated in the surface waters along an environmental gradient of Yong River in Ningbo, China. Water samples were collected from three zones: freshwaters in urban canals, brackish waters in the downstream Yong River, and coastal water of Hangzhou Bay. Shifts in activity and diversity of the ammonia oxidizers occurred with changes in salinity, ammonium and oxygen. The AOA abundance was always higher than that of AOB and related to the ammonia oxidation activity. The ratios of AOA/AOB in the brackish and marine waters were significantly higher than those found in freshwaters. Both AOA and AOB showed similar community compositions in brackish and marine waters, but only 31 and 35% similarity, respectively, between these waters and the urban inland freshwaters. Most of AOA-amoA sequences from freshwater were affiliated with sequences obtained from terrestrial environments and those collected from brackish and coastal areas were ubiquitous in marine, coastal, and terrestrial ecosystems. All AOB from freshwaters belonged to Nitrosomonas, and those from brackish and marine waters mainly belonged to Nitrosospira.

  20. Evaluation of pH, alkalinity and temperature during air stripping process for ammonia removal from landfill leachate.

    Science.gov (United States)

    Campos, Juacyara Carbonelli; Moura, Denise; Costa, Ana Paula; Yokoyama, Lidia; Araujo, Fabiana Valeria da Fonseca; Cammarota, Magali Christe; Cardillo, Luigi

    2013-01-01

    The objective of this research was to evaluate the air stripping technology for the removal of ammonia from landfill leachates. In this process, pH, temperature, airflow rate and operation time were investigated. Furthermore, the relationship between the leachate alkalinity and the ammonia removal efficiency during the process was studied. The leachate used in the tests was generated in the Gramacho Municipal Solid Waste Landfill (Rio de Janeiro State, Brazil). The best results were obtained with a temperature of 60(o)C, and they were independent of the pH value for 7 h of operation (the ammonia nitrogen removal was greater than 95%). A strong influence of the leachate alkalinity on the ammonia nitrogen removal was observed; as the alkalinity decreased, the ammonia concentration also decreased because of prior CO2 removal, which increased the pH and consequently favored the NH3 stripping. The air flow rate, in the values evaluated (73, 96 and 120 L air.h(-1).L(-1) of leachate), did not influence the results.

  1. Physisorption of ammonia on AISI 304L stainless steel at different surface temperature under high vacuum conditions

    Directory of Open Access Journals (Sweden)

    A. de Castro

    2016-12-01

    Full Text Available The physisorption of ammonia molecules (sticking on the walls of a stainless steel pipe (AISI 304L has been studied at different wall temperatures (323-473K. The total amount of ammonia that is retained on the walls, once equilibrium is reached, has been measured by differentially-pumped mass spectrometry in gas exposure laboratory experiments. The results show ammonia retentions in the range of μg/cm2 resulting in a multilayer adsorption with lower amounts of stuck ammonia at higher temperatures of the stainless steel surface. The sticking coefficient follows an exponential decay evolution with time. The activation energy of the process has been estimated by an Arrhenius fit, assuming that the characteristic time for this decay is inversely proportional to the kinetic adsorption constant. A value of 0.15eV per ammonia molecule has been obtained, being in agreement with nominal values for the physisorption of small molecules or atoms (CO, N2, Ar… that can be found in the specialized literature. The implication of these results in the possible extrapolation to the ITER vacuum system under nitrogen seeded plasma operation is also addressed.

  2. The excretion of isotope in urea and ammonia for estimating protein turnover in man with [15N]glycine

    International Nuclear Information System (INIS)

    Fern, E.B.; Garlick, P.J.; McNurlan, M.A.; Waterlow, J.C.

    1981-01-01

    Four normal adults were given [ 15 N]-glycine in a single dose either orally or intravenously. Rates of whole-body protein turnover were estimated from the excretion of 15 N in ammonia and in urea during the following 9 h. The rate derived from urea took account of the [ 15 N]urea retained in body water. In postabsorptive subjects the rates of protein synthesis given by ammonia were equal to those from urea, when the isotope was given orally, but lower when an intravenous dose was given. In subjects receiving equal portions of food every 2 h rates of synthesis calculated from ammonia were much lower than those from urea whether an oral or intravenous isotope was given. Comparison of rates obtained during the postabsorptive and absorptive periods indicated regulation by food intake primarily of synthesis when measurements were made on urea, but regulation primarily of breakdown when measurements were made on ammonia. These inconsistencies suggest that changes in protein metabolism might be assessed better by correlating results given by different end-products, and it is suggested that the mean value given by urea and ammonia will be useful for this purpose. (author)

  3. The Optical Properties of Ammonia Treated TiO2 Nano structure Prepared by Liquid Phase Deposition Method

    International Nuclear Information System (INIS)

    Siti Khadijah Mohd Saad; Akrajas Ali Umar; Mohd Yusri Abdul Rahman; Muhammad Mat Salleh

    2011-01-01

    TiO 2 was known for its potential in solar cell application. However the usage of anatase TiO 2 in solar cell application has its own disadvantage as TiO 2 spectrum was limited to ultraviolet (UV) light limiting its application. It was found that the broader optical absorption of TiO 2 can be obtained by nitrogen doping. This paper report the optical properties study of ammonia treated TiO 2 nano structures with various percentage concentration of ammonia. The TiO 2 nano structures was prepared by liquid phase deposition (LPD) method using on ITO substrate and annealed at 450 degree Celsius for 1h. The TiO 2 nano structures were characterized with rod-like morphology with length and diameter of ca. 100 nm and ca. 100 nm respectively that vertically oriented on the surface. The optical properties of the samples exhibit strong band near the UV region. The optical properties drastically changed if the samples treated with ammonia, of which exhibit the present of broader absorption band in the visible region. This might be due to the effective nitridization of TiO 2 by the ammonia of which agreed with the previously reported technique [1]. The TiO 2 treated ammonia should be find used in photoelectrochemical (PEC) solar cell application. (author)

  4. Alkaline Ammonia Electrolysis on Electrodeposited Platinum for Controllable Hydrogen Production.

    Science.gov (United States)

    Gwak, Jieun; Choun, Myounghoon; Lee, Jaeyoung

    2016-02-19

    Ammonia is beginning to attract a great deal of attention as an alternative energy source carrier, because clean hydrogen can be produced through electrolytic processes without the emission of COx . In this study, we deposited various shapes of Pt catalysts under potentiostatic mode; the electrocatalytic oxidation behavior of ammonia using these catalysts was studied in alkaline media. The electrodeposited Pt was characterized by both qualitative and quantitative analysis. To discover the optimal structure and the effect of ammonia concentration, the bulk pH value, reaction temperature, and applied current of ammonia oxidation were investigated using potential sweep and galvanostatic methods. Finally, ammonia electrolysis was conducted using a zero-gap cell, producing highly pure hydrogen with an energy efficiency over 80 %. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Ammonia effect on hydrogenotrophic methanogens and syntrophic acetate oxidizing bacteria

    DEFF Research Database (Denmark)

    Wang, Han; Fotidis, Ioannis; Angelidaki, Irini

    2015-01-01

    Ammonia-rich substrates can cause inhibition on anaerobic digestion process. Syntrophic acetate oxidizing bacteria (SAOB) and hydrogenotrophic methanogens are important for the ammonia inhibitory mechanism on anaerobic digestion. The roles and interactions of SAOB and hydrogenotrophic methanogens...... to ammonia inhibition effect are still unclear. The aim of the current study was to determine the ammonia toxicity levels of various pure strains of SAOB and hydrogenotrophic methanogens. Moreover, ammonia toxicity on the syntrophic cultivated strains of SAOB and hydrogenotrophic methanogens was tested. Thus......, four hydrogenotrophic methanogens (i.e. Methanoculleus bourgensis, Methanobacterium congolense, Methanoculleus thermophilus and Methanothermobacter thermautotrophicus), two SAOB (i.e. Tepidanaerobacter acetatoxydans and Thermacetogenium phaeum) and their syntrophic cultivation, were assessed under 0...

  6. Safety assessment of ammonia as a transport fuel

    DEFF Research Database (Denmark)

    Duijm, N.J.; Markert, Frank; Paulsen, Jette Lundtang

    2005-01-01

    of transport of ammonia to the refuelling stations and safety of the activities at the refuelling station (unloading and refuelling). Comparisons are made between the safety of using ammonia and the safety of otherexisting or alternative fuels. The conclusion is that the hazards in relation to ammonia need...... to be controlled by a combination of technical and regulatory measures. The most important requirements are: - Advanced safety systems in the vehicle -Additional technical measures and regulations are required to avoid releases in maintenance workshops and unauthorised maintenance on the fuel system. - Road...... transport of ammonia to refuelling stations in refrigerated form - Sufficient safety zonesbetween refuelling stations and residential or otherwise public areas. When these measures are applied, the use of ammonia as a transport fuel wouldn’t cause more risks than currently used fuels (using current practice)....

  7. Optimization of biomethanation focusing on high ammonia loaded processes

    DEFF Research Database (Denmark)

    Wang, Han

    The toxicity effect of high ammonia is one of the most common problems, which cause imbalance and low biogas production rate in biogas plants. When protein-rich substrates (e.g. pig manure and mink manure, food waste, etc.) are used in biogas plants, lead to suboptimal utilization of the biogas...... potential and unstable biogas process. However, up to now, the solutions for alleviating ammonia toxicity effect have been proven either too expensive or time consuming for the full-scale biogas plants. Thus, sustainable and practical solutions to overcome the problem of ammonia inhibition efficiently...... and subsequently been converted together with carbon dioxide to methane by hydrogenotrophic methanogens, could potentially be more tolerant to ammonia toxicity. Therefore, the effect of different ammonia levels on this hydrogen assisted biogas upgrading process under different hydrogen partial pressure (0, 0.25, 0...

  8. Formulation of coarse mesh finite difference to calculate mathematical adjoint flux

    International Nuclear Information System (INIS)

    Pereira, Valmir; Martinez, Aquilino Senra; Silva, Fernando Carvalho da

    2002-01-01

    The objective of this work is the obtention of the mathematical adjoint flux, having as its support the nodal expansion method (NEM) for coarse mesh problems. Since there are difficulties to evaluate this flux by using NEM. directly, a coarse mesh finite difference program was developed to obtain this adjoint flux. The coarse mesh finite difference formulation (DFMG) adopted uses results of the direct calculation (node average flux and node face averaged currents) obtained by NEM. These quantities (flux and currents) are used to obtain the correction factors which modify the classical finite differences formulation . Since the DFMG formulation is also capable of calculating the direct flux it was also tested to obtain this flux and it was verified that it was able to reproduce with good accuracy both the flux and the currents obtained via NEM. In this way, only matrix transposition is needed to calculate the mathematical adjoint flux. (author)

  9. Crystal growth of emerald by flux method

    International Nuclear Information System (INIS)

    Inoue, Mikio; Narita, Eiichi; Okabe, Taijiro; Morishita, Toshihiko.

    1979-01-01

    Emerald crystals have been formed in two binary fluxes of Li 2 O-MoO 2 and Li 2 O-V 2 O 5 using the slow cooling method and the temperature gradient method under various conditions. In the flux of Li 2 O-MoO 3 carried out in the range of 2 -- 5 of molar ratios (MoO 3 /Li 2 O), emerald was crystallized in the temperature range from 750 to 950 0 C, and the suitable crystallization conditions were found to be the molar ratio of 3 -- 4 and the temperature about 900 0 C. In the flux of Li 2 O-V 2 O 5 carried out in the range of 1.7 -- 5 of molar ratios (V 2 O 5 /Li 2 O), emerald was crystallized in the temperature range from 900 to 1150 0 . The suitable crystals were obtained at the molar ratio of 3 and the temperature range of 1000 -- 1100 0 C. The crystallization temperature rised with an increase in the molar ratio of the both fluxes. The emeralds grown in two binary fluxes were transparent green, having the density of 2.68, the refractive index of 1.56, and the two distinct bands in the visible spectrum at 430 and 600nm. The emerald grown in Li 2 O-V 2 O 5 flux was more bluish green than that grown in Li 2 O-MoO 3 flux. The size of the spontaneously nucleated emerald grown in the former flux was larger than the latter, when crystallized by the slow cooling method. As for the solubility of beryl in the two fluxes, Li 2 O-V 2 O 5 flux was superior to Li 2 O-MoO 3 flux whose small solubility of SiO 2 caused an experimental problem to the temperature gradient method. The suitability of the two fluxes for the crystal growth of emerald by the flux method was discussed from the view point of various properties of above-mentioned two fluxes. (author)

  10. Modelling of Cavitation of Wash-Out Water, Ammonia Water, Ammonia Water with Increased Content Ammonia and Hydrogen Sulphide, Tar Condensate

    Directory of Open Access Journals (Sweden)

    Josef DOBEŠ

    2013-12-01

    Full Text Available The aim is to design and implement a procedure of numerical modelling of cavitation of working mixtures: wash-out water, ammonia water, ammonia water with an increased content of hydrogen sulphide and ammonia, tar condensate. The numeric modelling is designed in the program Ansys Fluent using Schnerr-Sauer cavitation model. The issue of these liquids modelling can be solved by the cavitation simulation of water admixtures. Working fluids contain the following main ingredients: water, ammonia, carbon dioxide and hydrogen sulphide. Subsequently, a comparison of the amount of water vapor (reference liquid and given fluid vapor is executed. The Schnerr-Sauer model is chosen because of good results in previous simulations for water cavitation. As a geometry is selected Laval nozzle. Modelled liquid mixtures are used in the petrochemical industry, as a filling for fluid circuits where cavitation may occur and therefore the research is needed.

  11. Directed flux motor

    Science.gov (United States)

    Wilson, Andrew (Inventor); Punnoose, Andrew (Inventor); Strausser, Katherine (Inventor); Parikh, Neil (Inventor)

    2011-01-01

    A directed flux motor described utilizes the directed magnetic flux of at least one magnet through ferrous material to drive different planetary gear sets to achieve capabilities in six actuated shafts that are grouped three to a side of the motor. The flux motor also utilizes an interwoven magnet configuration which reduces the overall size of the motor. The motor allows for simple changes to modify the torque to speed ratio of the gearing contained within the motor as well as simple configurations for any number of output shafts up to six. The changes allow for improved manufacturability and reliability within the design.

  12. Ammonia emissions in agriculture: Proceedings of the First international ammonia conference 19-21 March 2007, Ede, The Netherlands

    NARCIS (Netherlands)

    Monteny, G.J.; Hartung, J.

    2007-01-01

    Ammonia emissions is an important topic in many countries with animal production, since it contributes to environmental and health problems. Strategies and measures to reduce ammonia emission are getting increasing attention in national and international legislation. The focus of this publication is

  13. Arterial ammonia with Blood Ammonia Checker II and with indophenol reaction to assess presence of hepatic encephalopathy

    NARCIS (Netherlands)

    Huizenga, [No Value; vanDam, GM; Gips, CH

    1996-01-01

    Hepatic encephalopathy (HE) is associated with elevated arterial ammonia levels. The relationship is variable, in part due to ammonia methodology. One method, based on the indophenol reaction (IPh), is interfered with a number of amino acids including all aromatic amino acids. We have determined

  14. Doppler spectroscopy of hydrogen Balmer lines in a hollow cathode glow discharge in ammonia and argon-ammonia mixture

    International Nuclear Information System (INIS)

    Sisovic, N. M.; Konjevic, N.

    2008-01-01

    The results of Doppler spectroscopy of hydrogen Balmer lines from a stainless steel (SS) and copper (Cu) hollow cathode (HC) glow discharge in ammonia and argon-ammonia mixture are reported. The experimental profiles in ammonia discharge are fitted well by superposing three Gaussian profiles. The half widths, in energy units, of narrow and medium Gaussians are in the ranges 0.3-0.4 eV and 3-4 eV, respectively, for both hollow cathodes what is expected on the basis of earlier electron beam→NH 3 experiments. The half widths of the largest Gaussian in ammonia are 46 and 55 eV for SS and Cu HC, respectively. In argon-ammonia discharge, three Gaussians are also required to fit experimental profiles. While half widths of narrow and medium Gaussians are similar to those in ammonia, the half widths of the largest Gaussians are 35 and 42 eV for SS and Cu HC, respectively. The half widths of the largest Gaussians in ammonia and in argon-ammonia mixture indicate the presence of excessive Doppler broadening.

  15. Asymmetric flux generation and its relaxation in reversed field pinch

    International Nuclear Information System (INIS)

    Arimoto, H.; Masamune, S.; Nagata, A.

    1985-02-01

    The toroidally asymmetric flux enhancement [''dynamo effect''] and the axisymmetrization of the enhanced fluxes that follows in the setting up phase of Reversed Field Pinch are investigated on the STP-3[M] device. A rapid increase in the toroidal flux generated by the dynamo effect is first observed near the poloidal and toroidal current feeders. Then, this inhomogeneity of the flux propagates toroidally towards the plasma current. The axisymmetrization of the flux is attained just after the maximum of plasma current. The MHD activities decrease significantly after this axisymmetrization and the quiescent period is obtained. (author)

  16. Neutron flux enhancement in the NRAD reactor

    International Nuclear Information System (INIS)

    Weeks, A.A.; Heidel, C.C.; Imel, G.R.

    1988-01-01

    In 1987 a series of experiments were conducted at the NRAD reactor facility at Argonne National Laboratory - West (ANL-W) to investigate the possibility of increasing the thermal neutron content at the end of the reactor's east beam tube through the use of hydrogenous flux traps. It was desired to increase the thermal flux for a series of experiments to be performed in the east radiography cell, in which the enhanced flux was required in a relatively small volume. Hence, it was feasible to attempt to focus the cross section of the beam to a smaller area. Two flux traps were constructed from unborated polypropylene and tested to determine their effectiveness. Both traps were open to the entire cross-sectional area of the neutron beam (as it emerges from the wall and enters the beam room). The sides then converged such that at the end of the trap the beam would be 'focused' to a greater intensity. The differences in the two flux traps were primarily in length, and hence angle to the beam as the inlet and outlet cross-sectional areas were held constant. The experiments have contributed to the design of a flux trap in which a thermal flux of nearly 10 9 was obtained, with an enhancement of 6.61

  17. Study of conversion of ammonia from urea water solution droplets using CFD

    Science.gov (United States)

    Jyothis, K.; Vikas, R.

    2017-09-01

    This paper deals with the numerical analysis of the spray behaviour of urea water solution (UWS) droplets used in Selective catalytic reduction (SCR) process. The study uses the ANSYS-Fluent-14 as a basic framework for numerical simulations. The evaporation modelling is based on multi-component droplet evaporation approach along with the consideration of Stefan flow. The urea decomposition treated as direct thermolysis approach, where the modelling is based on the single kinetic rate approach by the proper fitting of pre-exponent. This developed model was used for spray simulation of UWS droplet evaporation to determine the urea to ammonia conversion efficiency. The obtained spray simulation results were compared with the available experimental data. The comparison shows the pre-exponent developed in the study is suitable for direct thermolysis approach to get promising results in determining the ammonia conversion efficiency.

  18. Enhanced and selective ammonia sensing of reduced graphene oxide based chemo resistive sensor at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Ramesh, E-mail: rameshphysicsdu@gmail.com; Kaur, Amarjeet, E-mail: amarkaur@physics.du.ac.in [Department of Physics and Astrophysics, University of Delhi, Delhi-110007 (India)

    2016-05-06

    The reduced graphene oxide thin films were fabricated by using the spin coating method. The reduced graphene oxide samples were characterised by Raman studies to obtain corresponding D and G bands at 1360 and 1590 cm{sup −1} respectively. Fourier transform infra-red (FTIR) spectra consists of peak corresponds to sp{sup 2} hybridisation of carbon atoms at 1560 cm{sup −1}. The reduced graphene oxide based chemoresistive sensor exhibited a p-type semiconductor behaviour in ambient conditions and showed good sensitivity to different concentration of ammonia from 25 ppm to 500 ppm and excellent selectivity at room temperature. The sensor displays selectivity to several hazardous vapours such as methanol, ethanol, acetone and hydrazine hydrate. The sensor demonstrated a sensitivity of 9.8 at 25 ppm concentration of ammonia with response time of 163 seconds.

  19. N-carbamylglutamate augments ureagenesis and reduces ammonia and glutamine levels in patients with propionic acidemia

    Science.gov (United States)

    Mew, Nicholas Ah; McCarter, Robert; Daikhin, Yevgeny; Nissim, Itzhak; Yudkoff, Marc; Tuchman, Mendel

    2012-01-01

    Objective To determine whether N-carbamylglutamate reduces plasma levels of ammonia and glutamine and increases ureagenesis rate in patients with propionic acidemia Patients and Methods Identical four-hour studies were performed before and immediately after a 3-day trial of oral N-carbamylglutamate in 7 patients with propionic acidemia. An oral bolus of [13C]-sodium acetate was administered at the start of each study, and sequential blood samples were obtained to measure [13C]-urea, ammonia, urea and amino acids. Results With longitudinal mixed effects linear regression, peak [13C]urea increased following treatment with N-carbamylglutamate (from 2.2 μM to 3.8 μM; p propionic acidemia. The drug may serve as an important therapeutic adjunct in the treatment of acute hyperammonemia in this disorder. PMID:20566609

  20. Statistical modelling of variability in sediment-water nutrient and oxygen fluxes

    Science.gov (United States)

    Serpetti, Natalia; Witte, Ursula; Heath, Michael

    2016-06-01

    Organic detritus entering, or produced, in the marine environment is re-mineralised to inorganic nutrient in the seafloor sediments. The flux of dissolved inorganic nutrient between the sediment and overlying water column is a key process in the marine ecosystem, which binds the biogeochemical sub-system to the living food web. These fluxes are potentially affected by a wide range of physical and biological factors and disentangling these is a significant challenge. Here we develop a set of General Additive Models (GAM) of nitrate, nitrite, ammonia, phosphate, silicate and oxygen fluxes, based on a year-long campaign of field measurements off the north-east coast of Scotland. We show that sediment grain size, turbidity due to sediment re-suspension, temperature, and biogenic matter content were the key factors affecting oxygen consumption, ammonia and silicate fluxes. However, phosphate fluxes were only related to suspended sediment concentrations, whilst nitrate fluxes showed no clear relationship to any of the expected drivers of change, probably due to the effects of denitrification. Our analyses show that the stoichiometry of nutrient regeneration in the ecosystem is not necessarily constant and may be affected by combinations of processes. We anticipate that our statistical modelling results will form the basis for testing the functionality of process-based mathematical models of whole-sediment biogeochemistry.

  1. Neutron flux control systems validation

    International Nuclear Information System (INIS)

    Hascik, R.

    2003-01-01

    In nuclear installations main requirement is to obtain corresponding nuclear safety in all operation conditions. From the nuclear safety point of view is commissioning and start-up after reactor refuelling appropriate period for safety systems verification. In this paper, methodology, performance and results of neutron flux measurements systems validation is presented. Standard neutron flux measuring chains incorporated into the reactor protection and control system are used. Standard neutron flux measuring chain contains detector, preamplifier, wiring to data acquisition unit, data acquisition unit, wiring to display at control room and display at control room. During reactor outage only data acquisition unit and wiring and displaying at reactor control room is verified. It is impossible to verify detector, preamplifier and wiring to data acquisition recording unit during reactor refuelling according to low power. Adjustment and accurate functionality of these chains is confirmed by start-up rate (SUR) measurement during start-up tests after refuelling of the reactors. This measurement has direct impact to nuclear safety and increase operational nuclear safety level. Briefly description of each measuring system is given. Results are illustrated on measurements performed at Bohunice NPP during reactor start-up tests. Main failures and their elimination are described (Authors)

  2. Aeronet Solar Flux

    Data.gov (United States)

    National Aeronautics and Space Administration — SolRad-Net (Solar Radiation Network) is an established network of ground-based sensors providing high-frequency solar flux measurements in quasi-realtime to the...

  3. Flux in Tallinn

    Index Scriptorium Estoniae

    2004-01-01

    Rahvusvahelise elektroonilise kunsti sümpoosioni ISEA2004 klubiõhtu "Flux in Tallinn" klubis Bon Bon. Eestit esindasid Ropotator, Ars Intel Inc., Urmas Puhkan, Joel Tammik, Taavi Tulev (pseud. Wochtzchee). Klubiõhtu koordinaator Andres Lõo

  4. Determining Reactor Neutrino Flux

    OpenAIRE

    Cao, Jun

    2011-01-01

    Flux is an important source of uncertainties for a reactor neutrino experiment. It is determined from thermal power measurements, reactor core simulation, and knowledge of neutrino spectra of fuel isotopes. Past reactor neutrino experiments have determined the flux to (2-3)% precision. Precision measurements of mixing angle $\\theta_{13}$ by reactor neutrino experiments in the coming years will use near-far detector configurations. Most uncertainties from reactor will be canceled out. Understa...

  5. Theoretical magnetic flux emergence

    OpenAIRE

    MacTaggart, David

    2011-01-01

    Magnetic flux emergence is the subject of how magnetic fields from the solar interior can rise and expand into the atmosphere to produce active regions. It is the link that joins dynamics in the convection zone with dynamics in the atmosphere. In this thesis, we study many aspects of magnetic flux emergence through mathematical modelling and computer simulations. Our primary aim is to understand the key physical processes that lie behind emergence. The first chapter intro...

  6. Flux Emergence (Theory)

    Science.gov (United States)

    Cheung, Mark C. M.; Isobe, Hiroaki

    2014-07-01

    Magnetic flux emergence from the solar convection zone into the overlying atmosphere is the driver of a diverse range of phenomena associated with solar activity. In this article, we introduce theoretical concepts central to the study of flux emergence and discuss how the inclusion of different physical effects (e.g., magnetic buoyancy, magnetoconvection, reconnection, magnetic twist, interaction with ambient field) in models impact the evolution of the emerging field and plasma.

  7. Ammonia-Free NOx Control System

    Energy Technology Data Exchange (ETDEWEB)

    Song Wu; Zhen Fan; Andrew H. Seltzer; Richard G. Herman

    2004-09-30

    Research is being conducted under United States Department of Energy (DOE) Contract DEFC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia. This report describes the work performed during the July 1 to September 30, 2004 time period.

  8. Ammonia-Free NOx Control System

    Energy Technology Data Exchange (ETDEWEB)

    Song Wu; Zhen Fan; Andrew H. Seltzer

    2005-09-30

    Research is being conducted under United States Department of Energy (DOE) Contract DEFC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia. This report describes the work performed during the July 1 to September 30, 2005 time period.

  9. Ammonia-Free NOx Control System

    Energy Technology Data Exchange (ETDEWEB)

    Song Wu; Zhen Fan; Richard G. Herman

    2004-12-31

    Research is being conducted under United States Department of Energy (DOE) Contract DEFC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia. This report describes the work performed during the October 1 to December 30, 2004 time period.

  10. Towards an ammonia-mediated hydrogen economy?

    DEFF Research Database (Denmark)

    Christensen, Claus H.; Johannessen, Tue; Sørensen, Rasmus Zink

    2006-01-01

    . Recently, metal ammine salts were proposed as safe, reversible. high-density and low-cost hydrogen carriers. Here, we discuss how this development could provide a platform for using ammonia as a fuel for the hydrogen economy, We do that by comparing various possible hydrogen carriers with respect to energy......Materialization of a hydrogen economy could provide a solution to significant global challenges, In particular. the possibility of improving the efficiency and simultaneously minimizing the environmental impact of energy conversion processes, together with the opportunity to reduce the dependency...... of fossil fuels, are main drivers for the currently increasing research and development efforts. However. significant technological breakthroughs are necessary for making a hydrogen economy feasible. In particular, it is necessary to develop appropriate hydrogen storage and transportation technologies...

  11. Syntrophy of aerobic and anaerobic ammonia oxidisers.

    Science.gov (United States)

    Wett, B; Hell, M; Nyhuis, G; Puempel, T; Takacs, I; Murthy, S

    2010-01-01

    Deammonification is known as an efficient and resource saving sidestream process option to remove the nitrogen load from sludge liquors. The transfer of the intermediate product nitrite between both syntrophic groups of organisms - aerobic and anaerobic ammonia oxidizers (AOB) - appears very sensitive to process conditions such as temperature, dissolved oxygen (DO) and operating nitrite level. Growth kinetics for aerobic and anaerobic AOBs differ by one order of magnitude and require an adequate selection of sludge retention time. This paper provides measurement- and model-based results on how selected sludge wasting impacts population dynamics in a suspended growth deammonification system. Anammox enrichment up to a doubled portion in mixed liquor solids can substantially improve process stability in difficult conditions. A case-study on low temperature operations outlines two possible strategies to balance syntrophic consumption of ammonium and nitrite.

  12. Long-term ammonia removal in a coconut fiber-packed biofilter: analysis of N fractionation and reactor performance under steady-state and transient conditions.

    Science.gov (United States)

    Baquerizo, Guillermo; Maestre, Juan P; Machado, Vinicius C; Gamisans, Xavier; Gabriel, David

    2009-05-01

    A comprehensive study of long-term ammonia removal in a biofilter packed with coconut fiber is presented under both steady-state and transient conditions. Low and high ammonia loads were applied to the reactor by varying the inlet ammonia concentration from 90 to 260 ppm(v) and gas contact times ranging from 20 to 36 s. Gas samples and leachate measurements were periodically analyzed and used for characterizing biofilter performance in terms of removal efficiency (RE) and elimination capacity (EC). Also, N fractions in the leachate were quantified to both identify the experimental rates of nitritation and nitratation and to determine the N leachate distribution. Results showed stratification in the biofilter activity and, thus, most of the NH(3) removal was performed in the lower part of the reactor. An average EC of 0.5 kg N-NH(3)m(-3)d(-1) was obtained for the whole reactor with a maximum local average EC of 1.7 kg N-NH(3)m(-3)d(-1). Leachate analyses showed that a ratio of 1:1 of ammonium and nitrate ions in the leachate was obtained throughout steady-state operation at low ammonia loads with similar values for nitritation and nitratation rates. Low nitratation rates during high ammonia load periods occurred because large amounts of ammonium and nitrite accumulated in the packed bed, thus causing inhibition episodes on nitrite-oxidizing bacteria due to free ammonia accumulation. Mass balances showed that 50% of the ammonia fed to the reactor was oxidized to either nitrite or nitrate and the rest was recovered as ammonium indicating that sorption processes play a fundamental role in the treatment of ammonia by biofiltration.

  13. Neutron flux monitoring device

    International Nuclear Information System (INIS)

    Shimazu, Yoichiro.

    1995-01-01

    In a neutron flux monitoring device, there are disposed a neutron flux measuring means for outputting signals in accordance with the intensity of neutron fluxes, a calculation means for calculating a self power density spectrum at a frequency band suitable to an object to be measured based on the output of the neutron flux measuring means, an alarm set value generation means for outputting an alarm set value as a comparative reference, and an alarm judging means for comparing the alarm set value with the outputted value of the calculation means to judge requirement of generating an alarm and generate an alarm in accordance with the result of the judgement. Namely, the time-series of neutron flux signals is put to fourier transformation for a predetermined period of time by the calculation means, and from each of square sums for real number component and imaginary number component for each of the frequencies, a self power density spectrum in the frequency band suitable to the object to be measured is calculated. Then, when the set reference value is exceeded, an alarm is generated. This can reliably prevent generation of erroneous alarm due to neutron flux noises and can accurately generate an alarm at an appropriate time. (N.H.)

  14. Evaluation of mitigation strategies to reduce ammonia losses from slurry fertilisation on arable lands

    Energy Technology Data Exchange (ETDEWEB)

    Carozzi, M., E-mail: marco.carozzi@unimi.it [University of Milan, Department of Agricultural and Environmental Sciences, via Celoria 2, 20133 Milan (Italy); Ferrara, R.M.; Rana, G. [Consiglio per la Ricerca e sperimentazione in Agricoltura, Research Unit for Cropping Systems in Dry Environments, via C. Ulpiani, 5 – 70125 Bari (Italy); Acutis, M. [University of Milan, Department of Agricultural and Environmental Sciences, via Celoria 2, 20133 Milan (Italy)

    2013-04-01

    To evaluate the best practices in reducing ammonia (NH{sub 3}) losses from fertilised arable lands, six field trials were carried out in three different locations in northern Italy. NH{sub 3} emissions from cattle slurry were estimated considering the spreading techniques and the field incorporation procedures. The measurements were performed using long term exposure samplers associated to the determination of the atmospheric turbulence and the use of the backward Lagrangian stochastic (bLS) model WindTrax. The results obtained indicate that the NH{sub 3} emission process was exhausted in the first 24–48 h after slurry spreading. The slurry incorporation technique was able to reduce the NH{sub 3} losses with respect to the surface spreading, where a contextual incorporation led to reductions up to 87%. However, the best abatement strategy for NH{sub 3} losses from slurry applications has proved to be the direct injection into the soil, with a reduction of about 95% with respect to the surface spreading. The results obtained highlight the strong dependence of the volatilisation phenomenon by soil and weather conditions. - Highlights: ► Ammonia emissions from land-application of slurry were quantified. ► We examined and compared six different agronomic treatments in three locations. ► The faster was the soil-incorporation of slurry, the lower was the ammonia loss. ► The direct injection of slurry was found to be the best abatement strategy. ► The environmental factors were able to strongly influence the ammonia emission.

  15. Nitrogen metabolism and kinetics of ammonia-oxidizing archaea.

    Science.gov (United States)

    Martens-Habbena, Willm; Stahl, David A

    2011-01-01

    The discovery of ammonia-oxidizing mesophilic and thermophilic Group I archaea changed the century-old paradigm that aerobic ammonia oxidation is solely mediated by two small clades of Beta- and Gammaproteobacteria. Group I archaea are extremely diverse and ubiquitous in marine and terrestrial environments, accounting for 20-30% of the microbial plankton in the global oceans. Recent studies indicated that many of these organisms carry putative ammonia monooxygenase genes and are more abundant than ammonia-oxidizing bacteria in most natural environments suggesting a potentially significant role in the nitrogen cycle. The isolation of Nitrosopumilus maritimus strain SCM1 provided the first direct evidence that Group I archaea indeed gain energy from ammonia oxidation. To characterize the physiology of this archaeal nitrifier, we developed a respirometry setup particularly suited for activity measurements in dilute microbial cultures with extremely low oxygen uptake rates. Here, we describe the setup and review the kinetic experiments conducted with N. maritimus and other nitrifying microorganisms. These experiments demonstrated that N. maritimus is adapted to grow on ammonia concentrations found in oligotrophic open ocean environments, far below the survival threshold of ammonia-oxidizing bacteria. The described setup and experimental procedures should facilitate physiological studies on other nitrifying archaea and oligotrophic microorganisms in general. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. Ammonia recovery from landfill leachate using hydrophobic membrane contactors.

    Science.gov (United States)

    Amaral, Míriam C S; Magalhães, Nátalie C; Moravia, Wagner G; Ferreira, Carolina D

    2016-11-01

    This article aims to evaluate membrane contactors capability to remove and recover ammonia from landfill leachate (LFL). A hydrophobic hollow fiber membrane module was used to achieve such purpose. A sulfuric acid diluted solution was used as extraction solution to speed up ammonia content removal. Several factors that have influence on ammonia removal and recovery capability such as ammonia solution pH, concentration of sulfuric acid solutions and flow rate of liquid phases have been examined. Microfiltration was the method used as pretreatment. The results have shown that membrane contactor operated with LFL (pH 10), 0.1 M acid solution and liquid flow rate up to 0.5 L min -1 achieved 99.9% of ammonia removal, which corresponds to 79.1% of ammonia recovery from the extraction solution, and it is capable to produce highly purified ammonium sulfate solutions (41.2%, wt wt -1 ) to be used as fertilizer. The concentration of total ammonia nitrogen (TAN) in the residual LFL complies with Brazilian law requirements of 20.0 mg L -1 of TAN, regarding the disposal of effluents.

  17. Investigations of blood ammonia analysis: Test matrices, storage, and stability.

    Science.gov (United States)

    Goldstein, Brittany N; Wesler, Jordan; Nowacki, Amy S; Reineks, Edmunds; Natowicz, Marvin R

    2017-06-01

    An assessment of blood ammonia concentration is common medical practice in the evaluation of an individual with an unexplained mental status change or coma. The determination of a blood ammonia level is most commonly done using a glutamate dehydrogenase (GLDH)-based assay, although there are many potential sources of artifact and the literature is inconsistent regarding key preanalytic issues. Using a GLDH-based assay, we first investigated matrix effects using three anticoagulants: heparin, EDTA and oxalate. Heparin-anticoagulated plasma was substantially less precise than EDTA- and oxalate-anticoagulated plasma. Oxalate-anticoagulated plasma showed a greater baseline of apparent ammonia than either heparin- or EDTA-derived plasma, presumably due to interferants. We then evaluated the stability of EDTA-anticoagulated plasma for assessment of ammonia when stored at 4°C,-14°C or -70°C. There was a linear increase of ammonia with storage at both 4°C and -14°C. Plasma kept at -70°C for up to three weeks showed no change in measured ammonia relative to the baseline determination. This work clarifies preanalytic conditions for which a precise determination of ammonia can be accomplished using a GLDH-based assay. Copyright © 2017 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  18. Ammonia removal in electrochemical oxidation: Mechanism and pseudo-kinetics

    International Nuclear Information System (INIS)

    Li Liang; Liu Yan

    2009-01-01

    This paper investigated the mechanism and pseudo-kinetics for removal of ammonia by electrochemical oxidation with RuO 2 /Ti anode using batch tests. The results show that the ammonia oxidation rates resulted from direct oxidation at electrode-liquid interfaces of the anode by stepwise dehydrogenation, and from indirect oxidation by hydroxyl radicals were so slow that their contribution to ammonia removal was negligible under the condition with Cl - . The oxidation rates of ammonia ranged from 1.0 to 12.3 mg N L -1 h -1 and efficiency reached nearly 100%, primarily due to the indirect oxidation of HOCl, and followed pseudo zero-order kinetics in electrochemical oxidation with Cl - . About 88% ammonia was removed from the solution. The removed one was subsequently found in the form of N 2 in the produced gas. The rate at which Cl - lost electrons at the anode was a major factor in the overall ammonia oxidation. Current density and Cl - concentration affected the constant of the pseudo zero-order kinetics, expressed by k = 0.0024[Cl - ] x j. The ammonia was reduced to less than 0.5 mg N L -1 after 2 h of electrochemical oxidation for the effluent from aerobic or anaerobic reactors which treated municipal wastewater. This result was in line with the strict discharge requirements

  19. Arterial ammonia levels in the management of fulminant liver failure

    Directory of Open Access Journals (Sweden)

    Curry S

    2011-06-01

    Full Text Available Previous studies have suggested that an arterial ammonia level greater than 150 mmol/L is highly sensitive for predicting subsequent development of cerebral edema in patients with fulminant liver failure. We performed a prospective cohort study to confirm this relationship. We enrolled 22 consecutive patients who presented to our transplant hepatology service with grade 3-4 encephalopathy associated with fulminant liver failure. All patients underwent placement of an intraparenchymal ICP monitor, and every 12 hourly arterial ammonia levels. The prevalence of intracranial hypertension (IHTN in our population was 95% (21/22 patients, with 82 discrete episodes recorded. The sensitivity of arterial ammonia levels to predict the onset of IHTN was 62% (95% CI: 40.8 to 79.3 at a cut point of 150 mmol/L. Arterial ammonia levels preceding the first intracranial hypertension event were less than 150 mmol/L in 8 of 21 patients (39%. Fifty nine of 82 episodes of IHTN (73% occurred when arterial ammonia levels were less than 150 mmol/L. We conclude that the arterial ammonia level is not useful in making decisions regarding management related to cerebral edema in patients with fulminant liver failure. In fact, since almost all our study patients with grade III or IV encephalopathy secondary to fulminant liver failure went on to develop intracranial hypertension, our study supports the contention that all such patients might benefit from ICP monitoring regardless of arterial ammonia levels.

  20. Safety assessment of ammonia as a transport fuel

    Energy Technology Data Exchange (ETDEWEB)

    Duijm, N.J.; Markert, F.; Lundtang paulsen, Jette

    2005-02-01

    This report describes the safety study performed as part of the EU supported project 'Ammonia Cracking for Clean Electric Power Technology' The study addresses the following activities: safety of operation of the ammonia-powered vehicle under normal and accident (collision) conditions, safety of transport of ammonia to the refuelling stations and safety of the activities at the refuelling station (unloading and refuelling). Comparisons are made between the safety of using ammonia and the safety of other existing or alternative fuels. The conclusion is that the hazards in relation to ammonia need to be controlled by a combination of technical and regulatory measures. The most important requirements are: - Advanced safety systems in the vehicle - Additional technical measures and regulations are required to avoid releases in maintenance workshops and unauthorised maintenance on the fuel system - Road transport of ammonia to refuelling stations in refrigerated form - Sufficient safety zones between refuelling stations and residential or otherwise public areas. When these measures are applied, the use of ammonia as a transport fuel wouldnt cause more risks than currently used fuels (using current practice). (au)

  1. Mathematical Model of Ammonia Handling in the Rat Renal Medulla

    Science.gov (United States)

    Noiret, Lorette; Baigent, Stephen; Jalan, Rajiv; Thomas, S. Randall

    2015-01-01

    The kidney is one of the main organs that produces ammonia and release it into the circulation. Under normal conditions, between 30 and 50% of the ammonia produced in the kidney is excreted in the urine, the rest being absorbed into the systemic circulation via the renal vein. In acidosis and in some pathological conditions, the proportion of urinary excretion can increase to 70% of the ammonia produced in the kidney. Mechanisms regulating the balance between urinary excretion and renal vein release are not fully understood. We developed a mathematical model that reflects current thinking about renal ammonia handling in order to investigate the role of each tubular segment and identify some of the components which might control this balance. The model treats the movements of water, sodium chloride, urea, NH3 and NH4+, and non-reabsorbable solute in an idealized renal medulla of the rat at steady state. A parameter study was performed to identify the transport parameters and microenvironmental conditions that most affect the rate of urinary ammonia excretion. Our results suggest that urinary ammonia excretion is mainly determined by those parameters that affect ammonia recycling in the loops of Henle. In particular, our results suggest a critical role for interstitial pH in the outer medulla and for luminal pH along the inner medullary collecting ducts. PMID:26280830

  2. Dietary adipic acid reduces ammonia emission from swine excreta.

    Science.gov (United States)

    van Kempen, T A

    2001-09-01

    Adipic acid is only partially catabolized when it is fed to animals, and a portion of it is excreted in urine. The excreted portion may lower urinary pH and, as a result, ammonia emission. The present study tested this hypothesis. In Exp. 1, nursery pigs (n = 14) were fed (for a period of 7 d) either a standard nursery diet or the same diet supplemented with 1% adipic acid to assess effects on urinary pH (collected on d 5 or 6) and in vitro ammonia emission from the collected urine samples that were mixed with control feces. In Exp. 2, grower pigs housed 10 each in one of two chambers were fed a control diet or the same diet supplemented with 1% adipic acid. Ventilated air was quantified and analyzed for ammonia using Fourier transform infrared spectroscopy to determine the effects of feeding 1% adipic acid on ammonia emission. The results from Exp. 1 showed that adipic acid strongly reduced urinary pH (from 7.7 to 5.5, P < 0.05). In vitro ammonia emission from these urine samples was significantly reduced at all the time points evaluated (1, 3, 18, and 46 h with reductions of 94, 93, 70, and 39%, respectively, P < 0.05). Experiment 2 showed that adipic acid supplementation reduced ammonia emission by 25% (P < 0.05), which corresponded to the predicted reduction in ammonia emission based on the reduction in manure pH observed. In conclusion, feeding adipic acid lowers urinary pH and reduces ammonia emission. The reduction in ammonia emission, though, does not correspond to the reduction in urinary pH but corresponds to the reduction in fecal pH as a result of mixing the urine and feces, in which feces act as a strong buffer.

  3. Dry anaerobic ammonia-methane production from chicken manure.

    Science.gov (United States)

    Abouelenien, Fatma; Kitamura, Yoshiaki; Nishio, Naomichi; Nakashimada, Yutaka

    2009-03-01

    The effect of temperature on production of ammonia during dry anaerobic fermentation of chicken manure (CM), inoculated with thermophilic methanogenic sludge, was investigated in a batch condition for 8 days. Incubation temperature did not have a significant effect on the production of ammonia. Almost complete inhibition of production of methane occurred at 55 and 65 degrees C while quite low yields of 8.45 and 6.34 ml g(-1) VS (volatile solids) were observed at 35 and 45 degrees C due to a higher accumulation of ammonia. In order to improve the production of methane during dry anaerobic digestion of CM, stripping of ammonia was performed firstly on the CM previously fermented at 65 degrees C for 8 days: the stripping for 1 day at 85 degrees C and pH 10 removed 85.5% of ammonia. The first-batch fermentation of methane for 75 days was conducted next, using the ammonia-stripped CM inoculated with methanogenic sludge at different ratios, (CM: thermophilic sludge) of 1:2, 1:1, and 2:1 on volume per volume basis at both 35 and 55 degrees C. Production of methane improved and was higher than that of the control (without stripping of ammonia) but the yield of 20.4 ml g(-1) VS was still low, so second stripping of ammonia was conducted, which resulted in 74.7% removal of ammonia. A great improvement in the production of methane of 103.5 ml g(-1) VS was achieved during the second batch for 55 days.

  4. Effect of nitrogen fertilization and residue management practices on ammonia emissions from subtropical sugarcane production

    Science.gov (United States)

    mudi, Sanku Datta; Wang, Jim J.; Dodla, Syam Kumar; Arceneaux, Allen; Viator, H. P.

    2016-08-01

    Ammonia (NH3) emission from soil is a loss of nitrogen (N) nutrient for plant production as well as an issue of air quality, due to the fact that it is an active precursor of airborne particulate matters. Ammonia also acts as a secondary source of nitrous oxide (N2O) emission when present in the soil. In this study, the impacts of different sources of N fertilizers and harvest residue management schemes on NH3 emissions from sugarcane production were evaluated based on an active chamber method. The field experiment plots consisting of two sources of N fertilizer (urea and urea ammonium nitrate (UAN)) and two common residue management practices, namely residue retained (RR) and residue burned (RB), were established on a Commerce silt loam. The NH3 volatilized following N fertilizer application was collected in an impinger containing diluted citric acid and was subsequently analyzed using ion chromatography. The NH3 loss was primarily found within 3-4 weeks after N application. Average seasonal soil NH3 flux was significantly greater in urea plots with NH3-N emission factor (EF) twice or more than in UAN plots (2.4-5.6% vs. 1.2-1.7%). The RR residue management scheme had much higher NH3 volatilization than the RB treatment regardless of N fertilizer sources, corresponding to generally higher soil moisture levels in the former. Ammonia-N emissions in N fertilizer-treated sugarcane fields increased with increasing soil water-filled pore space (WFPS) up to 45-55% observed in the field. Both N fertilizer sources and residue management approaches significantly affected NH3 emissions.

  5. Liquid ammonia as a dipolar aprotic solvent for aliphatic nucleophilic substitution reactions.

    Science.gov (United States)

    Ji, Pengju; Atherton, John; Page, Michael I

    2011-03-04

    The rate constants for the reactions of a variety of nucleophiles reacting with substituted benzyl chlorides in liquid ammonia (LNH(3)) have been determined. To fully interpret the associated linear free-energy relationships, the ionization constants of phenols ions in liquid ammonia were obtained using UV spectra. These equilibrium constants are the product of those for ion-pair formation and dissociation to the free ions, which can be separated by evaluating the effect of added ammonium ions. There is a linear relationship between the pK(a) of phenols in liquid ammonia and those in water of slope 1.68. Aminium ions exist in their unprotonated free base form in liquid ammonia and their ionization constants could not be determined by NMR. The rates of solvolysis of substituted benzyl chlorides in liquid ammonia at 25 °C show a Hammett ρ of zero, having little or no dependence upon ring substituents, which is in stark contrast with the hydrolysis rates of substituted benzyl halides in water, which vary 10(7) fold. The rate of substitution of benzyl chloride by substituted phenoxide ions is first order in the concentration of the nucleophile indicative of a S(N)2 process, and the dependence of the rate constants on the pK(a) of the phenol in liquid ammonia generates a Brønsted β(nuc) = 0.40. Contrary to the solvolysis reaction, the reaction of phenoxide ion with 4-substituted benzyl chlorides gives a Hammett ρ = 1.1, excluding the 4-methoxy derivative, which shows the normal positive deviation. The second order rate constants for the substitution of benzyl chlorides by neutral and anionic amines show a single Brønsted β(nuc) = 0.21 (based on the aqueous pK(a) of amine), but their dependence on the substituent in substituted benzyl chlorides varies with a Hammett ρ of 0 for neutral amines, similar to that seen for solvolysis, whereas that for amine anions is 0.93, similar to that seen for phenoxide ion.

  6. The Open Flux Problem

    International Nuclear Information System (INIS)

    Linker, J. A.; Caplan, R. M.; Downs, C.; Riley, P.; Mikic, Z.; Lionello, R.; Henney, C. J.; Arge, C. N.; Liu, Y.; Derosa, M. L.; Yeates, A.; Owens, M. J.

    2017-01-01

    The heliospheric magnetic field is of pivotal importance in solar and space physics. The field is rooted in the Sun’s photosphere, where it has been observed for many years. Global maps of the solar magnetic field based on full-disk magnetograms are commonly used as boundary conditions for coronal and solar wind models. Two primary observational constraints on the models are (1) the open field regions in the model should approximately correspond to coronal holes (CHs) observed in emission and (2) the magnitude of the open magnetic flux in the model should match that inferred from in situ spacecraft measurements. In this study, we calculate both magnetohydrodynamic and potential field source surface solutions using 14 different magnetic maps produced from five different types of observatory magnetograms, for the time period surrounding 2010 July. We have found that for all of the model/map combinations, models that have CH areas close to observations underestimate the interplanetary magnetic flux, or, conversely, for models to match the interplanetary flux, the modeled open field regions are larger than CHs observed in EUV emission. In an alternative approach, we estimate the open magnetic flux entirely from solar observations by combining automatically detected CHs for Carrington rotation 2098 with observatory synoptic magnetic maps. This approach also underestimates the interplanetary magnetic flux. Our results imply that either typical observatory maps underestimate the Sun’s magnetic flux, or a significant portion of the open magnetic flux is not rooted in regions that are obviously dark in EUV and X-ray emission.

  7. The effect of gaseous ammonia on cobalt perrhenate

    International Nuclear Information System (INIS)

    Maslov, L.P.; Men'shikov, O.D.; Borisov, V.V.; Sorokin, S.I.; Krutovertsev, S.A.; Kharkevich, S.I.; Ivanova, O.M.

    1994-01-01

    The influence of humid air ammonia mixture on crystal pentahydrate of cobalt(2) perrhenate has been studied by the methods of PES, IR spectroscopy thermal analysis and electrophysical measurements. It is shown that with an increase in ammonia content in gaseous phase cobalt perrhenate successively transforms into diaquodiammine-, tetrammine- and μ-dioxo-bis-(tetrammine) derivatives of cobalt. Reversibility of dioxocomplex formation and a correlation between the change in electrophysical properties of crystal sample and change in ammonia content in gaseous phase are pointed out. 16 refs.; 4 figs.; 1 tab

  8. Erbium Doped Fiber Sensor for Ammonia Detection into Water

    International Nuclear Information System (INIS)

    Pérez-Sánchez, G G; Pinzón-Escobar, E F; Sandoval-Romero, G E; Chávez, J A Álvarez

    2015-01-01

    The water pollution is a health problem around the world. One of the most common pollutants in water is the Ammonia. Some sensors have been developed for Ammoniac detection even though most of them are not in real time and could be expensive. In this work an Erbium-doped fibre-sensor for Ammonia detection with a mechanical long period fibre grating and a taper in cascade for improving the sensitivity; the detection bandwidth is in the 1550 nm region from 1460 nm to 1640 nm. Output optical spectrum for Ammonia concentrations from 1ml to 5 ml is shown

  9. The Sugar Model: Autocatalytic Activity of the Triose Ammonia Reaction

    Science.gov (United States)

    Weber, Arthur L.

    2007-04-01

    Reaction of triose sugars with ammonia under anaerobic conditions yielded autocatalytic products. The autocatalytic behavior of the products was examined by measuring the effect of the crude triose ammonia reaction product on the kinetics of a second identical triose ammonia reaction. The reaction product showed autocatalytic activity by increasing both the rate of disappearance of triose and the rate of formation of pyruvaldehyde, the product of triose dehydration. This synthetic process is considered a reasonable model of origin-of-life chemistry because it uses plausible prebiotic substrates, and resembles modern biosynthesis by employing the energized carbon groups of sugars to drive the synthesis of autocatalytic molecules.

  10. Catalytic synthesis of ammonia using vibrationally excited nitrogen

    DEFF Research Database (Denmark)

    Henriksen, Niels Engholm; Billing, Gert D.; Hansen, Flemming Yssing

    1992-01-01

    In a previous study we have considered the catalytic synthesis of ammonia in the presence of vibrationally excited nitrogen. The distribution over vibrational states was assumed to be maintained during the reaction, and it was shown that the yield of ammonia increased considerably compared...... to that from conventional synthesis. In the present study the nitrogen molecules are only excited at the inlet of a plug flow reactor, and the importance of vibrational relaxation is investigated. We show that vibrational excitation can give an enhanced yield of ammonia also in the situation where vibrational...

  11. Treatment of biomass to obtain fermentable sugars

    Science.gov (United States)

    Dunson, Jr., James B.; Tucker, Melvin [Lakewood, CO; Elander, Richard [Evergreen, CO; Hennessey, Susan M [Avondale, PA

    2011-04-26

    Biomass is pretreated using a low concentration of aqueous ammonia at high biomass concentration. Pretreated biomass is further hydrolyzed with a saccharification enzyme consortium. Fermentable sugars released by saccharification may be utilized for the production of target chemicals by fermentation.

  12. Submersible microbial desalination cell for simultaneous ammonia recovery and electricity production from anaerobic reactors containing high levels of ammonia.

    Science.gov (United States)

    Zhang, Yifeng; Angelidaki, Irini

    2015-02-01

    High ammonia concentration in anaerobic reactors can seriously inhibit the anaerobic digestion process. In this study, a submersible microbial desalination cell (SMDC) was developed as an innovative method to lower the ammonia level in a continuous stirred tank reactor (CSTR) by in situ ammonia recovery and electricity production. In batch experiment, the ammonia concentration in the CSTR decreased from 6 to 0.7 g-N/L during 30 days, resulting in an average recovery rate of 80 g-N/m(2)/d. Meanwhile, a maximum power density of 0.71±0.5 W/m(2) was generated at 2.85 A/m(2). Both current driven NH4(+) migration and free NH3 diffusion were identified as the mechanisms responsible for the ammonia transportation. With an increase in initial ammonia concentration and a decrease in external resistance, the SMDC performance was enhanced. In addition, the coexistence of other cations in CSTR or cathode had no negative effect on the ammonia transportation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Biomass production and nutrient assimilation by a novel microalga, Monoraphidium spp. SDEC-17, cultivated in a high-ammonia wastewater

    International Nuclear Information System (INIS)

    Jiang, Liqun; Pei, Haiyan; Hu, Wenrong; Hou, Qingjie; Han, Fei; Nie, Changliang

    2016-01-01

    Highlights: • The algae Monoraphidium SDEC-17 was identified as a suitable feedstock for biofuel. • SDEC-17 has been domesticated to survive in high-ammonia wastewater (CW). • SDEC-17 exhibited robust growth and nutrient assimilation in CW. • CW improved protein accumulation of SDEC-17. - Abstract: To obtain suitable microalgae species for successful algal biomass production from low-cost wastewater, four axenic algae strains were isolated from a local lake. Through acclimation with the high-ammonia complex wastewater (CW) of a gourmet powder factory, one algae species showed good ability to yield biomass and endure high-ammonia conditions (>170 mg L −1 ) in CW. This was verified as a Monoraphidium spp. by molecular identification, and named as SDEC-17. The algae were 27–60 μm in length and 4–10 μm in width, with relatively low specific surface area for withstanding ammonia ingress through the cell membrane. The final biomass densities of SDEC-17 in CW (1.29 ± 0.09 g L −1 ) and BG11 medium (1.31 ± 0.08 g L −1 ) did not show a statistically significant difference (p > 0.05). Moreover, protein content was stimulated to 44% by CW, compared to 35% in BG11. Lipid accumulation of SDEC-17 was not significantly influenced by CW, and fatty acid profiles resembled those of palm oil. The algae would utilize ammonia first under conditions with various nitrogen sources present, and absorb large amounts of phosphorus from the wastewater. Thus, phosphorus and ammonia were removed with efficiencies of nearly 100%, satisfying the discharge standard of pollutants for municipal wastewater treatment plants. These results suggested that Monoraphidium spp. SDEC-17 is a promising candidate for algae biomass production and possibly chemical energy recovery from the complex wastewater.

  14. Ammonia removal from an aqueous solution and method for the production of a fertilizer material

    NARCIS (Netherlands)

    Kelder, E.M.; Ursem, W.N.J.; Roos, R.A.; Marijnissen, J.C.M.

    2011-01-01

    The invention provides method for the removal of ammonia from air and converting the ammonia in a fertilizer material, comprising (a) contacting at least part of the air with an aqueous liquid, wherein the aqueous liquid is a solvent for ammonia, to provide an ammonia containing aqueous

  15. 46 CFR 111.105-32 - Bulk liquefied flammable gas and ammonia carriers.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Bulk liquefied flammable gas and ammonia carriers. 111... gas and ammonia carriers. (a) Each vessel that carries bulk liquefied flammable gases or ammonia as a.... (2) The term “gas-dangerous” does not include the weather deck of an ammonia carrier. (c) Each...

  16. New efficient catalyst for ammonia synthesis: barium-promoted cobalt on carbon

    DEFF Research Database (Denmark)

    Hagen, Stefan; Barfod, Rasmus; Fehrmann, Rasmus

    2002-01-01

    Barium-promoted cobalt catalysts supported on carbon exhibit higher ammonia activities at synthesis temperatures than the commercial, multipromoted iron catalyst and also a lower ammonia......Barium-promoted cobalt catalysts supported on carbon exhibit higher ammonia activities at synthesis temperatures than the commercial, multipromoted iron catalyst and also a lower ammonia...

  17. Chromophores from photolyzed ammonia reacting with acetylene: Application to Jupiters Great Red Spot

    Science.gov (United States)

    Carlson, Robert W.; Baines, Kevin H.; Anderson, M. S.; Filacchione, G.; Simon, A. A.

    2016-01-01

    The high altitude of Jupiter's Great Red Spot (GRS) may enhance the upward flux of gaseous ammonia (NH3 ) into the high troposphere, where NH3 molecules can be photodissociated and initiate a chain of chemical reactions with downwelling acetylene molecules (C2H2 ). These reactions, experimentally studied earlier by (Ferris and Ishikawa [1987] Nature 326, 777-778) and (Ferris and Ishikawa [1988] J. Amer. Chem. Soc. 110, 4306-4312), produce chromophores that absorb in the visible and ultraviolet regions. In this work we photolyzed mixtures of NH3 and C2H2 using ultraviolet radiation with a wavelength of 214 nm and measured the spectral transmission of the deposited films in the visible region (400-740 nm). From these transmission data we estimated the imaginary indices of refraction. Assuming that ammonia grains at the top of the GRS clouds are coated with this material, we performed layered sphere and radiative transfer calculations to predict GRS reflection spectra. Comparison of those results with observed and previously unreported Cassini visible spectra and with true-color images of the GRS show that the unknown GRS chromophore is spectrally consistent with the coupled NH3-C2H2 photochemical products produced in our laboratory experiments. Using high-resolution mass spectrometry and infrared spectroscopy we infer that the chromophore-containing residue is composed of aliphatic azine, azo, and diazo compounds.

  18. Obtaining graphene nanoplatelets from various graphite intercalation compounds

    Science.gov (United States)

    Melezhyk, A.; Galunin, E.; Memetov, N.

    2015-11-01

    The work compares the exfoliation ability of different graphite materials (expanded graphite intercalation compound, thermally expanded and oxidatively intercalated graphites) and describes the properties of graphene nanoplatelets (GNPs) obtained dependently on intercalation/deintercalation conditions and reagents. Among the studied materials, the graphite intercalated with ammonium persulfate in sulfuric acid and expanded at 40 °C possesses the maximum ability for ultrasonic exfoliation in the presence of a surfactant. The exfoliation efficiency strongly depends on the content of water in sulfuric acid during the intercalation. The highest efficiency was achieved for the expanded graphite intercalation compound (EGIC) prepared in sulfuric acid containing diluted oleum, which may be explained by increased acidity of the medium and, correspondingly, redox potential of the persulfate compound. This is also related to increased amounts of oxygen groups in the GNPs obtained from the EGIC synthesized in 100% sulfuric acid and diluted oleum. Besides, the nature of surface groups on the GNPs strongly depends on the nature of a deintercalating reagent. Thus, the treatment of the EGIC with different nucleophilic molecules (such as water, ammonia, carbamide, hexamethylenetetramine, organic amines, etc.) can yield GNPs with various surface groups. The interaction between the EGIC and nucleophilic molecules does not only include the substitution of sulfate groups, but also redox reactions with participation of graphene layers. Depending on the nature of the nucleophile, those reactions can lead to the formation of different groups attached to the graphene surface. GNPs with almost pure surface were obtained when using ammonia and carbamide.

  19. Ammonia stress under high environmental ammonia induces Hsp70 and Hsp90 in the mud eel, Monopterus cuchia.

    Science.gov (United States)

    Hangzo, Hnunlalliani; Banerjee, Bodhisattwa; Saha, Shrabani; Saha, Nirmalendu

    2017-02-01

    The obligatory air-breathing mud eel (Monopterus cuchia) is frequently being challenged with high environmental ammonia (HEA) exposure in its natural habitats. The present study investigated the possible induction of heat shock protein 70 and 90 (hsp70, hsc70, hsp90α and hsp90β) genes and more expression of Hsp70 and Hsp90 proteins under ammonia stress in different tissues of the mud eel after exposure to HEA (50 mM NH 4 Cl) for 14 days. HEA resulted in significant accumulation of toxic ammonia in different body tissues and plasma, which was accompanied with the stimulation of oxidative stress in the mud eel as evidenced by more accumulation of malondialdehyde (MDA) and hydrogen peroxide (H 2 O 2 ) during exposure to HEA. Further, hyper-ammonia stress led to significant increase in the levels of mRNA transcripts for inducible hsp70 and hsp90α genes and also their translated proteins in different tissues probably as a consequence of induction of hsp70 and hsp90α genes in the mud eel. However, hyper-ammonia stress was neither associated with any significant alterations in the levels of mRNA transcripts for constitutive hsc70 and hsp90β genes nor their translated proteins in any of the tissues studied. More abundance of Hsp70 and Hsp90α proteins might be one of the strategies adopted by the mud eel to defend itself from the ammonia-induced cellular damages under ammonia stress. Further, this is the first report of ammonia-induced induction of hsp70 and hsp90α genes under hyper-ammonia stress in any freshwater air-breathing teleost.

  20. MHD energy fluxes for late type dwarfs

    Science.gov (United States)

    Rosner, R.; Musielak, Z. E.

    1987-01-01

    The efficiency of MHD wave generation by turbulent motions in stratified stellar atmospheres with embedded uniform magnetic fields is calculated. In contradiction with previous results, it is shown that there is no significant increase in the efficiency of wave generation because of the presence of magnetic fields, at least within the theory's limits of applicability. It is shown that MHD energy fluxes for late-type stars are less than those obtained for acoustic waves in a magnetic-field-free atmosphere, and do not vary enough for a given spectral type in order to explain observed UV and X-ray fluxes. Thus, the results show that MHD energy fluxes obtained if stellar surface magnetic fields are uniform cannot explain the observed stellar coronal emissions.

  1. Process for reprocessing and regenerating wash water containing ammonia. Verfahren zur Aufarbeitung und Regenerierung ammoniakhaltiger Waschwaesser

    Energy Technology Data Exchange (ETDEWEB)

    Krug, G.; Lahr, H.

    1978-10-05

    In order to produce nuclear fuels, an oxide hydrate gel is precipitated by hydrolysis from nitrate solutions of uranium, plutonium and thorium, which contains the rest of the precipitation chemicals and by-products of the reaction, which have to be removed before further processing. Apart from ammonium salts, the 2-3% solution of ammonia in water used as wash water contains small quantities of heavy metal salts after being used several times. The waste water containing ammonia is evaporated to a concentration of about 1000 g/litre and the vapour produced is washed with hot (above 100/sup 0/C) 30% caustic soda solution before condensation, in order to prevent dissolving of oxide particles by wash water containing carbonate. The regenerate obtained in this way, which is now free of carbonate, can be used to wash the oxide hydrate gel out, after adding the ammonia. The soda solution produced in this washing out or the soda produced by drying is the only waste product of the process, apart from filter material.

  2. Diversity of aerobic and anaerobic ammonia-oxidizing bacteria in marine sponges.

    Science.gov (United States)

    Mohamed, Naglaa M; Saito, Keiko; Tal, Yossi; Hill, Russell T

    2010-01-01

    Aerobic ammonia-oxidizing bacteria (AAOB) are known to have an important function in the marine nitrogen cycle. Anaerobic ammonium oxidation (anammox) carried out by some members of Planctomycetales is also an important process in marine ecosystems. Ammonia-monooxygenase gene (amoA) fragments were amplified to investigate the potential for nitrification and the diversity of the AAOB in two marine sponges Ircinia strobilina and Mycale laxissima. All of the AmoA sequences obtained from the two sponges clustered with the AmoA sequences of the Betaproteobacteria Nitrosospira spp. To investigate the anaerobic ammonia-oxidizing bacteria (AnAOB) in sponges, 16S rRNA gene fragments of Planctomycetales and anammox bacteria were also amplified with specific primers, and clone libraries were constructed. The Planctomycetales diversity detected in the two sponges was different. The Planctomycetales community in M. laxissima was affiliated with Pirellula, Planctomyces and anammox bacteria, while all of the I. strobilina Planctomycetales clones were solely affiliated with the candidate phylum 'Poribacteria'. Interestingly, sequences related to anammox genera were recovered only from M. laxissima. This is the first report of anammox bacteria in marine sponges. It is intriguing to find AAOB and AnAOB in M. laxissima, but the nature of their interaction with the sponge host and with each other remains unclear. This work further supports the potential of sponge-associated microorganisms for nitrification and sheds light on anammox as a new aspect of the nitrogen cycle in marine sponges.

  3. Biomass production from electricity using ammonia as an electron carrier in a reverse microbial fuel cell.

    Directory of Open Access Journals (Sweden)

    Wendell O Khunjar

    Full Text Available The storage of renewable electrical energy within chemical bonds of biofuels and other chemicals is a route to decreasing petroleum usage. A critical challenge is the efficient transfer of electrons into a biological host that can covert this energy into high energy organic compounds. In this paper, we describe an approach whereby biomass is grown using energy obtained from a soluble mediator that is regenerated electrochemically. The net result is a separate-stage reverse microbial fuel cell (rMFC that fixes CO₂ into biomass using electrical energy. We selected ammonia as a low cost, abundant, safe, and soluble redox mediator that facilitated energy transfer to biomass. Nitrosomonas europaea, a chemolithoautotroph, was used as the biocatalyst due to its inherent capability to utilize ammonia as its sole energy source for growth. An electrochemical reactor was designed for the regeneration of ammonia from nitrite, and current efficiencies of 100% were achieved. Calculations indicated that overall bioproduction efficiency could approach 2.7±0.2% under optimal electrolysis conditions. The application of chemolithoautotrophy for industrial bioproduction has been largely unexplored, and results suggest that this and related rMFC platforms may enable biofuel and related biochemical production.

  4. Biomass production from electricity using ammonia as an electron carrier in a reverse microbial fuel cell.

    Science.gov (United States)

    Khunjar, Wendell O; Sahin, Asli; West, Alan C; Chandran, Kartik; Banta, Scott

    2012-01-01

    The storage of renewable electrical energy within chemical bonds of biofuels and other chemicals is a route to decreasing petroleum usage. A critical challenge is the efficient transfer of electrons into a biological host that can covert this energy into high energy organic compounds. In this paper, we describe an approach whereby biomass is grown using energy obtained from a soluble mediator that is regenerated electrochemically. The net result is a separate-stage reverse microbial fuel cell (rMFC) that fixes CO₂ into biomass using electrical energy. We selected ammonia as a low cost, abundant, safe, and soluble redox mediator that facilitated energy transfer to biomass. Nitrosomonas europaea, a chemolithoautotroph, was used as the biocatalyst due to its inherent capability to utilize ammonia as its sole energy source for growth. An electrochemical reactor was designed for the regeneration of ammonia from nitrite, and current efficiencies of 100% were achieved. Calculations indicated that overall bioproduction efficiency could approach 2.7±0.2% under optimal electrolysis conditions. The application of chemolithoautotrophy for industrial bioproduction has been largely unexplored, and results suggest that this and related rMFC platforms may enable biofuel and related biochemical production.

  5. Production of Diamino propionic acid ammonia lyase by a new strain of Salmonella typhimurium PU011

    Directory of Open Access Journals (Sweden)

    Shiva Kumar Vasanth V

    2002-03-01

    Full Text Available Abstract Background Seeds of the legume plant Lathyrus sativus, which is grown in arid and semi arid tropical regions, contain Diamino Propionic acid (DAP. DAP is a neurotoxin, which, when consumed, causes a disease called Lathyrism. Lathryrism may manifest as Neurolathyrism or Osteolathyrism, in which the nervous system, and bone formation respectively, are affected. DAP ammonia lyase is produced by a few microorganisms such as Salmonella typhi, Salmonella typhimurium and Pseudomonas, and is capable of detoxifying DAP. Results S. typhimurium PU011, a non-virulent bacterial strain isolated in our lab, was found to produce DAP ammonia lyase enzyme when grown in minimal medium containing DAP. There was a direct correlation between biomass yield and enzyme activity, until 16 h post inoculation in minimal medium containing DAP. Following ammonium sulphate precipitation and passing through Sephadex G100, CM-Sephadex and DEAE-Sephacel for crude enzyme extract preparation, about 68-fold enzyme purity was obtained. The purified enzyme gave maximum activity at pH 8.0 and was stable up to 45 degrees C. The Km value for the substrate was found to be 0.685mM, calculated from a Line Weaver Burk plot. Conclusion A new bacterial strain, S.typhimurium PU 011, which is capable of producing DAP ammonia lyase, was isolated.

  6. Room Temperature Ammonia Gas Sensing Using Mixed Conductor based TEMPOS Structures

    Directory of Open Access Journals (Sweden)

    Amita Chandra

    2008-10-01

    Full Text Available The current/voltage characteristics of mixed (ion+electron conductor-based ‘TEMPOS’ (Tunable Electronic Material with Pores in Oxide on Silicon structures are reported. TEMPOS are novel electronic MOS-like structures having etched swift heavy ion tracks (i.e., nanopores in the dielectric layer filled with some conducting material. The three contacts (two on top and one on the bottom, which resemble the classical bipolar or field effect transistor arrangements are, in principle, interchangeable when the overall electrical resistance along the tracks and on the surface are similar. Consequently, three configurations are obtained by interchanging the top contacts with the base contact in electronic circuits. The current/voltage characteristics show a diode like behaviour. Impedance measurements have been made for TEMPOS structures with tracks filled with ion conductors and also mixed conductors to study the ammonia sensing behaviour. The impedance has been found to be a function of frequency and magnitude of the applied signal and concentration of the ammonia solution. This is attributed to the large number of charge carriers (here protons available for conduction on exposure to ammonia and also to the large surface to volume ratio of the polymer composites embedded in the ion tracks. The measurement of both, the real and imaginary parts of impedance allows one to enhance the detection sensitivity greatly.

  7. Room Temperature Ammonia Gas Sensing Using Mixed Conductor based TEMPOS Structures.

    Science.gov (United States)

    Saroch, Mamta; Srivastava, Sunita; Fink, Dietmar; Chandra, Amita

    2008-10-14

    The current/voltage characteristics of mixed (ion+electron) conductor-based 'TEMPOS' (Tunable Electronic Material with Pores in Oxide on Silicon) structures are reported. TEMPOS are novel electronic MOS-like structures having etched swift heavy ion tracks (i.e., nanopores) in the dielectric layer filled with some conducting material. The three contacts (two on top and one on the bottom), which resemble the classical bipolar or field effect transistor arrangements are, in principle, interchangeable when the overall electrical resistance along the tracks and on the surface are similar. Consequently, three configurations are obtained by interchanging the top contacts with the base contact in electronic circuits. The current/voltage characteristics show a diode like behaviour. Impedance measurements have been made for TEMPOS structures with tracks filled with ion conductors and also mixed conductors to study the ammonia sensing behaviour. The impedance has been found to be a function of frequency and magnitude of the applied signal and concentration of the ammonia solution. This is attributed to the large number of charge carriers (here protons) available for conduction on exposure to ammonia and also to the large surface to volume ratio of the polymer composites embedded in the ion tracks. The measurement of both, the real and imaginary parts of impedance allows one to enhance the detection sensitivity greatly.

  8. Promotion of Nb2O5 on the wustite-based iron catalyst for ammonia synthesis

    International Nuclear Information System (INIS)

    Han, Wenfeng; Huang, Shiliang; Cheng, Tianhong; Tang, Haodong; Li, Ying; Liu, Huazhang

    2015-01-01

    Highlights: • Niobium enhances the reduction of wustite-based ammonia synthesis catalyst significantly. • Nb 2 O 5 inhibits the segregation or formation of solid solutions on the catalyst surface. • Nb 2 O 5 doping enhances the growth rates of [2 1 1] and [2 0 0] planes rather than their amounts. - Abstract: Niobium was selected and investigated as a potential promoter for wustite-based catalyst (WBC) for ammonia synthesis. Experiments on reduction performance, activity test and H 2 -TGA, in situ XRD as well as XPS were carried out to obtain the promotion effect and mechanism involved. Niobium as a promoter was confirmed to enhance the reduction of WBC significantly. This behavior is highly desired for industry in terms of catalyst regeneration and lesser pretreatment time for fabrication regardless the unimproved catalytic performance for Nb 2 O 5 -doped wustite-based catalyst (Nb-WBC). Possible reasons for these phenomena are discussed. It is suggested that Nb 2 O 5 is not favorable for the segregation or formation of solid solutions on the catalyst surface, which are difficult to be reduced. However, it seems that niobium does not promote the growth of [2 1 1] plane, which is active for ammonia synthesis.

  9. Vaporization reduction characteristics of aqueous ammonia solutions by the addition of ethylene glycol, glycerol and glycine to the CO2 absorption process.

    Science.gov (United States)

    Seo, Jong-Beom; Jeon, Soo-Bin; Kim, Je-Young; Lee, Gang-Woo; Jung, Jong-Hyeon; Oh, Kwang-Joong

    2012-01-01

    Aqueous ammonia (NH3) solution can be used as an alternative absorption for the control of CO2 emitted from flue gases due to its high absorption capacity, fast absorption rate and low corrosion problem. The emission of CO2 from iron and steel plants requires much attention, as they are higher than those emitted from power plants at a single point source. In the present work, low concentration ammonia liquor, 9 wt.%, was used with various additives to obtain the kinetic properties using the blast furnace gas model. Although a solution with a high ammonia concentration enables high CO2 absorption efficiency, ammonium ions are lost as ammonia vapor, resulting in reduced CO2 absorption due to the lower concentration of the ammonia absorbent. To decrease the vaporization of ammonia, ethylene glycol, glycerol and glycine, which contain more than one hydroxyl radical, were chosen. The experiments were conducted at 313 K similar to the CO2 absorption conditions for the blast furnace gas model.

  10. Applying an Inverse Model to Estimate Ammonia Emissions at Cattle Feedlots Using Three Different Observation-Based Approaches

    Science.gov (United States)

    Shonkwiler, K. B.; Ham, J. M.; Nash, C.

    2014-12-01

    Accurately quantifying emissions of ammonia (NH3) from confined animal feeding operations (CAFOs) is vital not only to the livestock industry, but essential to understanding nitrogen cycling along the Front Range of Colorado, USA, where intensive agriculture, urban sprawl, and pristine ecosystems (e.g., Rocky Mtn Nat'l Park) lie within 100-km of each other. Most observation-based techniques for estimating NH3 emissions can be expensive and highly technical. Many methods rely on concentration observations on location, which implicitly depends on weather conditions. A system for sampling NH3 using on-site weather data was developed to allow remote measurement of NH3 in a simple, cost-effective way. These systems use passive diffusive cartridges (Radiello, Sigma-Aldrich) that provide time-averaged concentrations representative of a typical two-week deployment. Cartridge exposure is robotically managed so they are only visible when winds are 1.4 m/s or greater from the direction of the CAFO. These concentration data can be coupled with stability parameters (measured on-site) in a simple inverse model to estimate emissions (FIDES, UMR Environnement et Grandes Cultures). Few studies have directly compared emissions estimates of NH3 using concentration data obtained from multiple measurement systems at different temporal and spatial scales. Therefore, in the summer and autumn of 2014, several conditional sampler systems were deployed at a 25,000-head cattle feedlot concomitant with an open-path infrared laser (GasFinder2, Boreal Laser Inc.) and a Cavity Ring Down Spectrometer (CRDS) (G1103, Picarro Inc.) which each measured instantaneous NH3 concentrations. This study will test the sampler technology by first comparing concentration data from the three different methods. In livestock research, it is common to estimate NH3 emissions by using such instantaneous data in a backward Lagrangian stochastic (bLs) model (WindTrax, Thunder Beach Sci.) Considering this, NH3 fluxes

  11. Eddy Correlation Flux Measurement System Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Cook, D. R. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-01-01

    The eddy correlation (ECOR) flux measurement system provides in situ, half-hour measurements of the surface turbulent fluxes of momentum, sensible heat, latent heat, and carbon dioxide (CO2) (and methane at one Southern Great Plains extended facility (SGP EF) and the North Slope of Alaska Central Facility (NSA CF). The fluxes are obtained with the eddy covariance technique, which involves correlation of the vertical wind component with the horizontal wind component, the air temperature, the water vapor density, and the CO2 concentration. The instruments used are: • a fast-response, three-dimensional (3D) wind sensor (sonic anemometer) to obtain the orthogonal wind components and the speed of sound (SOS) (used to derive the air temperature) • an open-path infrared gas analyzer (IRGA) to obtain the water vapor density and the CO2 concentration, and • an open-path infrared gas analyzer (IRGA) to obtain methane density and methane flux at one SGP EF and at the NSA CF. The ECOR systems are deployed at the locations where other methods for surface flux measurements (e.g., energy balance Bowen ratio [EBBR] systems) are difficult to employ, primarily at the north edge of a field of crops. A Surface Energy Balance System (SEBS) has been installed collocated with each deployed ECOR system in SGP, NSA, Tropical Western Pacific (TWP), ARM Mobile Facility 1 (AMF1), and ARM Mobile Facility 2 (AMF2). The surface energy balance system consists of upwelling and downwelling solar and infrared radiometers within one net radiometer, a wetness sensor, and soil measurements. The SEBS measurements allow the comparison of ECOR sensible and latent heat fluxes with the energy balance determined from the SEBS and provide information on wetting of the sensors for data quality purposes. The SEBS at one SGP and one NSA site also support upwelling and downwelling PAR measurements to qualify those two locations as Ameriflux sites.

  12. Cultivation and Genomic Analysis of “Candidatus Nitrosocaldus islandicus,” an Obligately Thermophilic, Ammonia-Oxidizing Thaumarchaeon from a Hot Spring Biofilm in Graendalur Valley, Iceland

    Directory of Open Access Journals (Sweden)

    Anne Daebeler

    2018-02-01

    Full Text Available Ammonia-oxidizing archaea (AOA within the phylum Thaumarchaeota are the only known aerobic ammonia oxidizers in geothermal environments. Although molecular data indicate the presence of phylogenetically diverse AOA from the Nitrosocaldus clade, group 1.1b and group 1.1a Thaumarchaeota in terrestrial high-temperature habitats, only one§ enrichment culture of an AOA thriving above 50°C has been reported and functionally analyzed. In this study, we physiologically and genomically characterized a newly discovered thaumarchaeon from the deep-branching Nitrosocaldaceae family of which we have obtained a high (∼85% enrichment from biofilm of an Icelandic hot spring (73°C. This AOA, which we provisionally refer to as “Candidatus Nitrosocaldus islandicus,” is an obligately thermophilic, aerobic chemolithoautotrophic ammonia oxidizer, which stoichiometrically converts ammonia to nitrite at temperatures between 50 and 70°C. “Ca. N. islandicus” encodes the expected repertoire of enzymes proposed to be required for archaeal ammonia oxidation, but unexpectedly lacks a nirK gene and also possesses no identifiable other enzyme for nitric oxide (NO generation§. Nevertheless, ammonia oxidation by this AOA appears to be NO-dependent as “Ca. N. islandicus” is, like all other tested AOA, inhibited by the addition of an NO scavenger. Furthermore, comparative genomics revealed that “Ca. N. islandicus” has the potential for aromatic amino acid fermentation as its genome encodes an indolepyruvate oxidoreductase (iorAB as well as a type 3b hydrogenase, which are not present in any other sequenced AOA. A further surprising genomic feature of this thermophilic ammonia oxidizer is the absence of DNA polymerase D genes§ – one of the predominant replicative DNA polymerases in all other ammonia-oxidizing Thaumarchaeota. Collectively, our findings suggest that metabolic versatility and DNA replication might differ substantially between obligately

  13. Cultivation and Genomic Analysis of "Candidatus Nitrosocaldus islandicus," an Obligately Thermophilic, Ammonia-Oxidizing Thaumarchaeon from a Hot Spring Biofilm in Graendalur Valley, Iceland.

    Science.gov (United States)

    Daebeler, Anne; Herbold, Craig W; Vierheilig, Julia; Sedlacek, Christopher J; Pjevac, Petra; Albertsen, Mads; Kirkegaard, Rasmus H; de la Torre, José R; Daims, Holger; Wagner, Michael

    2018-01-01

    Ammonia-oxidizing archaea (AOA) within the phylum Thaumarchaeota are the only known aerobic ammonia oxidizers in geothermal environments. Although molecular data indicate the presence of phylogenetically diverse AOA from the Nitrosocaldus clade, group 1.1b and group 1.1a Thaumarchaeota in terrestrial high-temperature habitats, only one enrichment culture of an AOA thriving above 50°C has been reported and functionally analyzed. In this study, we physiologically and genomically characterized a newly discovered thaumarchaeon from the deep-branching Nitrosocaldaceae family of which we have obtained a high (∼85%) enrichment from biofilm of an Icelandic hot spring (73°C). This AOA, which we provisionally refer to as " Candidatus Nitrosocaldus islandicus," is an obligately thermophilic, aerobic chemolithoautotrophic ammonia oxidizer, which stoichiometrically converts ammonia to nitrite at temperatures between 50 and 70°C. " Ca. N. islandicus" encodes the expected repertoire of enzymes proposed to be required for archaeal ammonia oxidation, but unexpectedly lacks a nirK gene and also possesses no identifiable other enzyme for nitric oxide (NO) generation. Nevertheless, ammonia oxidation by this AOA appears to be NO-dependent as " Ca. N. islandicus" is, like all other tested AOA, inhibited by the addition of an NO scavenger. Furthermore, comparative genomics revealed that " Ca. N. islandicus" has the potential for aromatic amino acid fermentation as its genome encodes an indolepyruvate oxidoreductase ( iorAB ) as well as a type 3b hydrogenase, which are not present in any other sequenced AOA. A further surprising genomic feature of this thermophilic ammonia oxidizer is the absence of DNA polymerase D genes - one of the predominant replicative DNA polymerases in all other ammonia-oxidizing Thaumarchaeota. Collectively, our findings suggest that metabolic versatility and DNA replication might differ substantially between obligately thermophilic and other AOA.

  14. Cultivation and Genomic Analysis of “Candidatus Nitrosocaldus islandicus,” an Obligately Thermophilic, Ammonia-Oxidizing Thaumarchaeon from a Hot Spring Biofilm in Graendalur Valley, Iceland

    Science.gov (United States)

    Daebeler, Anne; Herbold, Craig W.; Vierheilig, Julia; Sedlacek, Christopher J.; Pjevac, Petra; Albertsen, Mads; Kirkegaard, Rasmus H.; de la Torre, José R.; Daims, Holger; Wagner, Michael

    2018-01-01

    Ammonia-oxidizing archaea (AOA) within the phylum Thaumarchaeota are the only known aerobic ammonia oxidizers in geothermal environments. Although molecular data indicate the presence of phylogenetically diverse AOA from the Nitrosocaldus clade, group 1.1b and group 1.1a Thaumarchaeota in terrestrial high-temperature habitats, only one§ enrichment culture of an AOA thriving above 50°C has been reported and functionally analyzed. In this study, we physiologically and genomically characterized a newly discovered thaumarchaeon from the deep-branching Nitrosocaldaceae family of which we have obtained a high (∼85%) enrichment from biofilm of an Icelandic hot spring (73°C). This AOA, which we provisionally refer to as “Candidatus Nitrosocaldus islandicus,” is an obligately thermophilic, aerobic chemolithoautotrophic ammonia oxidizer, which stoichiometrically converts ammonia to nitrite at temperatures between 50 and 70°C. “Ca. N. islandicus” encodes the expected repertoire of enzymes proposed to be required for archaeal ammonia oxidation, but unexpectedly lacks a nirK gene and also possesses no identifiable other enzyme for nitric oxide (NO) generation§. Nevertheless, ammonia oxidation by this AOA appears to be NO-dependent as “Ca. N. islandicus” is, like all other tested AOA, inhibited by the addition of an NO scavenger. Furthermore, comparative genomics revealed that “Ca. N. islandicus” has the potential for aromatic amino acid fermentation as its genome encodes an indolepyruvate oxidoreductase (iorAB) as well as a type 3b hydrogenase, which are not present in any other sequenced AOA. A further surprising genomic feature of this thermophilic ammonia oxidizer is the absence of DNA polymerase D genes§ – one of the predominant replicative DNA polymerases in all other ammonia-oxidizing Thaumarchaeota. Collectively, our findings suggest that metabolic versatility and DNA replication might differ substantially between obligately thermophilic and

  15. Risk analysis and emergency management of ammonia installations

    NARCIS (Netherlands)

    Ham, J.M.; Gansevoort, J.

    1992-01-01

    The use of Quantitative Risk Assessment has been increasing for evaluating the risk of handling hazardous materials and land-use planning. This article reports on several studies carried out on the risk of handling, storage and transport of ammonia.

  16. Development of High-Performance Ammonia Borane Based Rocket Propellants

    Data.gov (United States)

    National Aeronautics and Space Administration — Ammonia borane based fuels for use in hybrid rocket systems have the potential to be high performing while at the same time mitigating many of the issues associated...

  17. Different cultivation methods to acclimatise ammonia-tolerant methanogenic consortia

    DEFF Research Database (Denmark)

    Tian, Hailin; Fotidis, Ioannis; Mancini, Enrico

    2017-01-01

    Bioaugmentation with ammonia tolerant-methanogenic consortia was proposed as a solution to overcome ammonia inhibition during anaerobic digestion process recently. However, appropriate technology to generate ammonia tolerant methanogenic consortia is still lacking. In this study, three basic...... reactors (i.e. batch, fed-batch and continuous stirred-tank reactors (CSTR)) operated at mesophilic (37°C) and thermophilic (55°C) conditions were assessed, based on methane production efficiency, incubation time, TAN/FAN (total ammonium nitrogen/free ammonia nitrogen) levels and maximum methanogenic...... activity. Overall, fed-batch cultivation was clearly the most efficient method compared to batch and CSTR. Specifically, by saving incubation time up to 150%, fed-batch reactors were acclimatised to nearly 2-fold higher FAN levels with a 37%-153% methanogenic activity improvement, compared to batch method...

  18. Ammonia effect on hydrogenotrophic methanogens and syntrophic acetate oxidizing bacteria

    DEFF Research Database (Denmark)

    Wang, Han; Fotidis, Ioannis; Angelidaki, Irini

    methanogens. Two pure strains of hydrogenotrophic methanogens (i.e: Methanoculleus bourgensis and Methanoculleus thermophiles) and two pure strains of SAO bacteria (i.e: Tepidanaerobacter acetatoxydans and Thermacetogenium phaeum) were inoculated under four different ammonia (0.26, 3, 5 and 7g NH4+-N....../L) and free ammonia levels (Mesophilic: 3.31, 38.2, 63.68 and 89.15 g NH3-N/L. Thermophilic: 8.48, 97.82, 163.03 and 228.24 g NH3-N/L). The results indicated that both T. acetatoxydans and T. phaeum were more sensitive to high ammonia levels compared to the hydrogenotrophic methanogens tested. Additionally......, the total incubation periods of hydrogenotrophic methanogens were significantly shorter compared to the SAO bacteria incubation periods. Thus, it seems that hydrogenotrophic methanogens could be equally, if not more, tolerant to high ammonia levels compared to SAO bacteria....

  19. Computation of Equilibrium Partial Vapor Pressures of Aqueous Ammonia Solutions

    National Research Council Canada - National Science Library

    Field, Paul

    2000-01-01

    This report evaluates all available vapor-liquid equilibria (VLE) data from low-to-moderate pressures over the normal liquid water temperature range for the highly non-ideal aqueous ammonia solutions spanning nearly a century...

  20. The production of ammonia by multiheme cytochromes C.

    Science.gov (United States)

    Simon, Jörg; Kroneck, Peter M H

    2014-01-01

    The global biogeochemical nitrogen cycle is essential for life on Earth. Many of the underlying biotic reactions are catalyzed by a multitude of prokaryotic and eukaryotic life forms whereas others are exclusively carried out by microorganisms. The last century has seen the rise of a dramatic imbalance in the global nitrogen cycle due to human behavior that was mainly caused by the invention of the Haber-Bosch process. Its main product, ammonia, is a chemically reactive and biotically favorable form of bound nitrogen. The anthropogenic supply of reduced nitrogen to the biosphere in the form of ammonia, for example during environmental fertilization, livestock farming, and industrial processes, is mandatory in feeding an increasing world population. In this chapter, environmental ammonia pollution is linked to the activity of microbial metalloenzymes involved in respiratory energy metabolism and bioenergetics. Ammonia-producing multiheme cytochromes c are discussed as paradigm enzymes.